CN115290520A - Mobile fine particle online calibration method - Google Patents
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Abstract
The embodiment of the invention provides a mobile fine particulate matter online calibration method, which comprises the following steps: moving the mobile fine particulate matter monitor online calibration system to a working place where the calibrated fine particulate matter monitor is located; placing a vehicle-mounted gravimetric method standard device and a calibrated fine particle monitoring instrument at a close spatial position in a vehicle-mounted mobile platform; the method comprises the following steps that an aerosol generator is connected to emit an ambient air sample outwards in the form of emitting aerosol, wherein one path of aerosol enters a vehicle-mounted gravimetric method standard device, and the other path of aerosol enters a calibrated fine particulate matter monitoring instrument; recording the mass concentration value of the fine particulate matter of the vehicle-mounted gravimetric method standard device as a first concentration value; recording the mass concentration value of the fine particles of the calibrated fine particle monitoring instrument in the same sampling measurement time as a second concentration value; and comparing the first concentration value with the second concentration value to realize comparison and calibration of the fine particle monitoring instrument. The on-line calibration of the automatic monitor is realized.
Description
Technical Field
The invention relates to the field of fine particle detection instrument calibration, in particular to a mobile fine particle online calibration method.
Background
Fine particulate matter such as PM 2.5 Is a ubiquitous and very complex air pollutant and is the focus of the research on the atmospheric environment particulate matters. Because of its large amount and surface area, it affects the visibility of the atmosphere, produces photochemical smog in the atmosphere, and exacerbates the greenhouse effect. Except visibility and climate influence, especially aerosol particles have serious influence and harm on human health. When PM 2.5 At an annual average concentration of 35 micrograms per cubic meter, the risk of death in humans increases by about 15% over the case of 10 micrograms per cubic meter. PM (particulate matter) 2.5 Can also be used as a carrier of viruses and bacteria, and isThe spread of respiratory infectious diseases is promoted. Therefore, increasing emphasis is placed on PM 2.5 The study of (1).
To ensure PM 2.5 The measuring instrument is accurate and reliable, and the instrument must be measured, calibrated or compared regularly. PM currently used in environmental monitoring 2.5 The concentration measuring instruments are in ten thousand, and only about 1700 instruments of the national control site of the department of ecological environment are in ten thousand. Most of the instruments are installed on an outdoor monitoring site, the instruments are used on line, have large volume and are difficult to send, correct and compare, and the instruments are difficult to move for a long time in order to ensure the continuity of measured data; therefore, the laboratory calibration method is difficult to completely meet the calibration comparison requirements of the instruments due to poor mobility, low timeliness, small coverage and the like.
Disclosure of Invention
The embodiment of the invention provides a mobile fine particulate matter online calibration method, which comprises the steps of moving a mobile fine particulate matter online calibration system to a working site of a fine particulate matter monitor through a vehicle-mounted mobile platform, measuring the concentration of fine particulate matters in the atmosphere under the same condition through a vehicle-mounted gravimetric method standard device, and comparing the measured concentration of the fine particulate matters in the atmosphere with the measured concentration of the fine particulate matters in the atmosphere measured by an automatic monitoring instrument to realize online calibration of the automatic monitor.
In order to achieve the above object, an embodiment of the present invention provides a mobile fine particulate matter online calibration method, which is implemented by using an online calibration system of a mobile fine particulate matter monitor, where the online calibration system of the mobile fine particulate matter monitor includes: the system comprises a vehicle-mounted mobile platform, a vehicle-mounted gravimetric method standard device and an aerosol generator, wherein the vehicle-mounted gravimetric method standard device and the aerosol generator are arranged on the vehicle-mounted mobile platform; and calibrating the fine particle monitoring instrument on line by using the mobile fine particle monitoring instrument on-line calibration system. The mobile fine particulate matter online calibration method comprises the following steps:
moving the mobile fine particle monitor online calibration system to a working place where the calibrated fine particle monitor is located; placing a vehicle-mounted gravimetric method standard device and a fine particulate matter monitoring instrument at a near space position in a vehicle-mounted mobile platform; setting relevant parameters of a vehicle-mounted gravimetric method standard device, setting relevant parameters of a fine particulate matter monitoring instrument, and starting the vehicle-mounted gravimetric method standard device and the calibrated fine particulate matter monitoring instrument at the same time; an aerosol generator is used for dividing an ambient air sample into two paths in an aerosol form and emitting the two paths outwards at the same constant flow rate, the first path of aerosol is emitted to a vehicle-mounted gravimetric method standard device, and the second path of aerosol is emitted to a fine particulate matter monitoring instrument; the vehicle-mounted gravimetric method standard device receives the first path of aerosol through the first blank filter membrane to obtain a first dust film, calculates the mass concentration of fine particles in the ambient air sample according to the first dust film, and records the mass concentration as a first concentration value; the fine particle monitor receives the second path of aerosol through the second blank filter membrane to obtain a second dust film, and calculates a fine particle mass concentration value in the ambient air sample according to the second dust film, and records the fine particle mass concentration value as a second concentration value; wherein, the sampling and measuring time of the aerosol by the vehicle-mounted gravimetric method standard device and the fine particulate matter monitoring instrument is the same; and comparing the first concentration value with the second concentration value, carrying out online calibration on the fine particulate matter monitoring instrument according to a comparison result, and calibrating the detection precision of the fine particulate matter monitoring instrument on the fine particulate matter to be within a preset range.
The technical scheme has the following beneficial effects: the on-line calibration system for the mobile fine particulate matters is moved to the working site of the fine particulate matter monitor through the vehicle-mounted mobile platform, the concentration of the fine particulate matters in the atmosphere under the same condition is measured through the vehicle-mounted weight method standard device, and the concentration of the fine particulate matters in the atmosphere measured by the automatic monitoring instrument is compared, so that the on-line calibration of the automatic monitoring instrument is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of an embodiment of the present invention for on-line calibration of fine particulate matter; FIG. 2 is a top view block diagram of a vehicle fine particulate calibration platform according to an embodiment of the present invention; FIG. 3 is a vehicle platform temperature change (summer) for an embodiment of the present invention; FIG. 4 is a graph of the humidity change (summer) of the vehicle platform of an embodiment of the present invention; FIG. 5 is a vehicle platform temperature change (winter) for an embodiment of the present invention; FIG. 6 is an illustration of the humidity change (winter) of the vehicle platform of an embodiment of the present invention; FIG. 7 is a schematic diagram of an on-board fine particulate matter gravimetric method standard apparatus of an embodiment of the present invention; FIG. 8 is a schematic structural diagram of a vehicle-mounted fine particulate matter standard measurement system according to an embodiment of the invention; FIG. 9 is a schematic diagram of temperature and humidity control of an environmental control unit according to an embodiment of the present invention; fig. 10 is a structural layout diagram of an automatic sample balance measurement system according to an embodiment of the present invention; FIG. 11 is a schematic diagram of an electronic control system of an embodiment of the present invention; FIG. 12 is a block diagram of a cooling and dehumidifying module according to an embodiment of the present invention; FIG. 13 is an effect diagram of an auto-sample _ balance _ measurement system according to an embodiment of the present invention; FIG. 14 is a schematic diagram of the operation of a sampling module of an embodiment of the present invention; FIG. 15 is a flow chart of blank filter membrane equilibration according to an embodiment of the present invention; FIG. 16 is a schematic flow chart illustrating the weighing of a single dust film according to an embodiment of the present invention; FIG. 17 is a control flow diagram of an embodiment of the present invention; FIG. 18 is a front view of an apparatus according to an embodiment of the invention; FIG. 19 is a right side view of an apparatus of an embodiment of the present invention; FIG. 20 is a graph showing the temperature change of the constant temperature and humidity chamber according to the embodiment of the present invention; FIG. 21 is a graph showing the humidity change in the constant temperature and humidity chamber according to the embodiment of the present invention; FIG. 22 is a zero point stability test of an embodiment of the present invention; FIG. 23 is a PEFT filter weighing stability test according to an embodiment of the invention; FIG. 24 is a sample flow stability test of an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1-24, the present invention is a mobile fine particle online calibration system and method, and aims to solve the technical problems: the existing fine particulate matter calibration method is implemented by sending calibrated instruments to units qualified for calibration, the calibrated instruments are fixedly installed, and if the calibrated instruments do not move, online use is needed, data continuity is needed, and the implementation is difficult. And the existing calibration devices are too bulky.
A mobile fine particulate matter online calibration method is implemented by adopting a mobile fine particulate matter monitor online calibration system, and the mobile fine particulate matter monitor online calibration system comprises: the system comprises a vehicle-mounted mobile platform, a vehicle-mounted gravimetric method standard device and an aerosol generator, wherein the vehicle-mounted gravimetric method standard device and the aerosol generator are arranged on the vehicle-mounted mobile platform; and calibrating the fine particle monitoring instrument on line by using the mobile fine particle monitoring instrument on-line calibration system. Moving the mobile fine particle monitor online calibration system to a working place where the calibrated fine particle monitor is located; placing a vehicle-mounted gravimetric method standard device (fixedly placed) and a fine particle monitoring instrument at a position close to a desktop cabinet part in a vehicle-mounted mobile platform; setting relevant parameters of a vehicle-mounted gravimetric method standard device, setting relevant parameters of a fine particulate matter monitoring instrument, and starting the gravimetric method standard device and the calibrated fine particulate matter monitoring instrument at the same time; an aerosol generator is used for dividing an ambient air sample into two paths in an aerosol form and emitting the two paths outwards at the same constant flow rate, the first path of aerosol is emitted to a vehicle-mounted gravimetric method standard device, and the second path of aerosol is emitted to a fine particulate matter monitoring instrument; the vehicle-mounted gravimetric method standard device receives the first path of aerosol through the first blank filter membrane to obtain a first dust film, calculates the mass concentration of fine particles in the ambient air sample according to the first dust film, and records the mass concentration as a first concentration value; the fine particle monitor receives the second path of aerosol through the second blank filter membrane to obtain a second dust film, and calculates the mass concentration value of fine particles in the environmental air sample according to the second dust film, and records the mass concentration value as a second concentration value; wherein, the sampling and measuring time of the aerosol by the vehicle-mounted gravimetric method standard device and the fine particulate matter monitoring instrument is the same; and comparing the first concentration value with the second concentration value, carrying out online calibration on the fine particulate matter monitoring instrument according to a comparison result, and calibrating the detection precision of the fine particulate matter monitoring instrument on the fine particulate matter to be within a preset range.
The system provides a moving carrier meeting environmental requirements for a gravimetric method standard device, realizes the moving function of a gravimetric method calibration device, and realizes the online calibration movement, temperature and humidity control of a fine particulate matter detection instrument; all the work of laboratory environment calibration is realized, atmospheric aerosol under the test field environment can be directly used as a calibration dust source according to the relevant environmental protection standards, and the comparison and calibration of a standard instrument and a calibrated instrument are realized. The calibration working principle is as follows: the on-line fine particle monitor calibrating device (system) is moved to the working site of the calibrated instrument (monitoring station, etc.), and the on-line fine particle monitor calibrating device and the calibrated fine particle monitor are placed at the same spatial position as much as possible (refer to HJ653 ambient air Particulate Matter (PM) 10 And PM 2.5 ) Technical specification of a continuous automatic monitoring system), setting relevant parameters of a calibrating device and a calibrated particulate monitor, starting up for measurement at the same time, recording the mass concentration values of fine particles in the same sampling and measuring time respectively, comparing the mass concentration values to serve as a standard instrument and a quantity value transmission standard, realizing online calibration of the fine particle monitor by a comparison method, and realizing comparison and calibration of the calibrated instrument, as shown in figure 1. The vehicle-mounted mobile device realizes on-site calibration and comparison, is flexible, can save a large amount of manpower and time cost, and is easier to popularize and promote. An effective detection and supervision means is provided for the protection blue sky engineering in various places in the dust monitoring field.
Vehicle platform car body outside special facilities: 1. retractable shock absorption spring columns are arranged on the periphery of the vehicle body; 2. the tail of the vehicle is provided with a simple ladder climbing to the top of the vehicle; 3. the retractable fence is arranged around the roof and is 100-200 mm high; 4.4 roof holes with the diameter of 10cm are drilled, extend out of the straight pipe and are provided with rain covers; 5. the bridge plate can be put down at the tail of the vehicle, so that the equipment can be moved out of the carriage conveniently; 5. the load of the anti-skid floor with the thickness of 5mm in the vehicle is 5 to 7 tons; 6. two 220V power sockets are arranged on the left side and the right side of the carriage respectively; 7. the carriage is insulated by 60mm, and the total thickness is 70mm.
The vehicle-mounted fine particulate matter standard measurement platform shown in FIG. 7 comprises: the system comprises an environment control subsystem, an automatic sampling _ balance _ measurement system, an electric control system and a vibration reduction system. Adopt upper and lower split type design, when improving the vibration isolation performance, be convenient for dismouting, transportation and maintenance. The electric control system comprises an electric control panel, a touch display screen, a switch control button, a mobile workstation and the like, and is designed and arranged according to the principle of man-machine engineering to realize convenient and efficient man-machine interaction. The electric control system also comprises a control unit of the automatic sampling _ balance _ measuring system and the environment control system, and an operation and alarm light control unit. The electric control system is used for the sampling unit, the measuring unit, the motion control unit, the environment monitoring unit and the data processing unit. The motion control unit is divided into filter membrane transfer and failure alarm, and the control flow chart is shown in figure 17. The core component of the PLC is a microprocessor, the functions of controlling the machine and the like are realized through editing programs, and the mechanical manufacturing process of each link can be controlled by changing an input/output mode.
Preferably, the sampling position, the balance position, the measuring position and the mechanical arm are uniformly distributed on the table top of the working cabin, can be observed in real time through the observation window, and can realize isolation of the internal environment and the external environment.
The vehicle-mounted gravimetric method standard device comprises a sampling module, a balancing module, a measuring module and a manipulator module; the full-automatic sampling, balancing and accurate measuring functions are realized; the structural schematic diagram of the vehicle-mounted fine particulate matter standard measurement system is shown in FIG. 8. The sampling module comprises sampling cutting head, temperature sensor, pressure sensor, mass Flow Controller (MFC), negative pressure air supply (this design adopts the vacuum pump) (wherein sampling cutting head and sensor all arrange the automobile body in outward).
The vehicle-mounted gravimetric method standard device receives a first path of aerosol through a first blank filter membrane, calculates the mass concentration of fine particles in an ambient air sample according to a first dust membrane, and records the mass concentration as a first concentration value, and specifically comprises:
the sampling module flow control system comprises a pressure sensor, a temperature sensor, a sampling cutter, a filter membrane, a mass flow controller, a vacuum pump, a control unit and the like. During gas sampling, an ambient air sample sequentially passes through the cutter, the filter membrane, the pipeline filter, the mass flow controller and the vacuum pump at a constant flow rate. The working principle diagram of the sampling module is shown in figure 14.
The first path of aerosol enters a sampling module of a vehicle-mounted gravimetric method standard device at a constant flow, and reaches a first blank filter membrane after passing through a cutter and a pipeline in the sampling module in sequence; classifying the fine particles of the environmental air sample according to the diameter size by a cutter, and passing through a corresponding first blank filter membrane while classifying; the first blank filter membrane acquires fine particles of corresponding levels to finish sampling of an ambient air sample; meanwhile, the vacuum pump adopts a gas balance compensation method to avoid sampling flow fluctuation; wherein the grade of the fine particles obtained by the first blank filter membrane is the same as the grade of the fine particles obtained by the fine particle detection instrument;
the sampling pipeline device can reduce the flow due to the increase of the resistance of the filter membrane along with the advance of time in the process of sampling the environmental air sample, the flow sensor, the proportional valve and the flow control panel form a closed loop system, the mass flow sensor is used for collecting the instantaneous flow of the environmental air sample at the filter membrane, the PID circuit is used for controlling the electromagnetic proportional valve to adjust the instantaneous flow of the first air inlet according to the instantaneous flow based on the fuzzy PID control algorithm of the BP neural network, the flow change caused by the increase of the resistance of the filter membrane is corrected in real time, and the constant flow in the sampling pipeline device is ensured; the MFC mass flow controller controls the sampling flow, and can accurately control the mass flow of the air flow in a large measuring range in an online real-time manner. The gas mass flow is measured by a method that the gas flow flows through a stainless steel capillary tube to change the temperature distribution of the capillary tube and cause the temperature difference between the upstream and the downstream; different from the types of flow meters such as a pressure measurement method and a volume measurement method, the flow precision of the flow meter is not influenced by gas pressure and ambient temperature. The upstream and downstream temperature difference measuring circuit signals feed back the instantaneous flow of the airflow in real time, and the flow is accurately controlled by controlling the electromagnetic proportional valve in real time through the PID circuit, so the method is particularly suitable for online real-time accurate measurement and control of the gas flow in the process.
The volume of the gas changes along with the change of the environmental temperature and the pressure, air pressure sensors are arranged in front of and behind the filter membrane in the flow direction of the environmental air sample, and the air pressure sensors are used for monitoring the filter membrane pressure before and after sampling in real time; the temperature and the humidity of the gas in the space where the vehicle-mounted gravimetric method standard device is located are collected in real time through a temperature and humidity sensor, and compensation calculation of the pressure, the temperature and the humidity is carried out on the gas in the space where the vehicle-mounted gravimetric method standard device is located according to an ideal gas state calculation formula, so that the purpose of accurately controlling the flow in the sampling pipeline to be constant is achieved; and the sampling quality is ensured. Various data generated during the on-line calibration process are viewed through the flow control panel. The position of the temperature and humidity sensor is as follows: the side on which a computer is hung outside is left, the other side is right, and the front side of the computer is provided with a door which can be opened in the platform.
Preferably, the method further comprises the following steps: before the environmental air sample is emitted outwards in an aerosol form at the same constant flow rate in two paths by the aerosol generator, weighing a first blank filter membrane required by the vehicle-mounted gravimetric method standard device and a second blank filter membrane required by the fine particulate matter monitor respectively; weighing the first dust film after the first dust film is obtained to obtain the weight of the first dust film, and taking the difference between the weight of the first dust film and the weight of the first blank filter membrane as the first weight of fine particles attached to the first blank dust film; and weighing the second dust film after the second dust film is obtained to obtain the weight of the second dust film, and taking the difference between the weight of the second dust film and the weight of the second blank filter membrane as the second weight of the fine particles attached to the second blank dust film.
Wherein, weighing blank filter membrane specifically includes:
as shown in fig. 10, the core is a manipulator module, the structure line is a manipulator motion track, the track covers the sampling position, the measuring position and the balance position, the sampling position, the balance position and the measuring position are connected in series, and the manipulator realizes the transfer of the blank film and the dust film among three target positions. In the filter membrane balancing process, the filter membrane storage rack needs to meet storage positions of storage quantity (8 filter membranes); the blank filter membrane is convenient to observe and operate when being distributed and placed. The blank filter equilibration flow chart is shown in FIG. 15. The filter membrane balance comprises the balance of a blank filter membrane and a dust membrane, the flow is basically consistent, as shown in fig. 15, the equipment is opened, and the internal environment of the upper cabinet is purified (about 30 min). Filter membrane storage rack for putting blank filter membrane into manipulatorBalancing the blank filter membrane for a first preset time period (24 hours can be set), and then, the first constant weight of the blank filter membrane is reached; the blank filter membrane is moved into a high-precision balance from the balance position through a manipulator, and the blank filter membrane is weighed through the high-precision balance to obtain the weight m 1 (ii) a The manipulator is a cylindrical coordinate type robot, has certain advantages for plane positioning, does not have an X-axis track and has a Z axis with preset strength compared with a three-coordinate type robot, and the operation track of the cylindrical coordinate type robot is sector motion and lifting motion rotating around the circle center; the total volume is little, the structure is succinct compact, intensity and stability are better. The sliding along the track is changed into the rotation around the circle center, so that the radial movement of the Z-axis track is reduced, the manipulator only does fan-shaped movement and lifting movement, the positioning is more accurate, the repeated positioning precision is higher, and the like. The effect diagram of the automatic sampling balance measuring system is shown in fig. 13.
Moving the blank filter membrane back to the balance position of the filter membrane storage rack, balancing the blank filter membrane for a second preset time period, and then reaching the second constant weight of the blank filter membrane; displacing the blank filter membrane from the balance position to a high-precision balance by a manipulator, and weighing the blank filter membrane again by the high-precision balance to obtain the weight m 2 (ii) a The second preset time period is less than the first preset time period; after the mechanical handle filter membrane is transmitted to the high-precision balance, the system automatically acquires the mass data of the sample through R232 communication.
Calculate m for blank Filter 1 And m 2 M of the blank filter membrane is judged 1 And m 2 Is less than a predetermined threshold value, if m of the blank filter membrane 1 And m 2 Is not more than a preset threshold (e.g. 40 ug), the weighing of the blank filter is completed, the weight of the blank filter is m 1 And m 2 Average value of (a); if m of blank filter 1 And m 2 If the difference value is larger than the preset threshold value, the blank filter membrane is repeatedly moved back to the balance position of the filter membrane storage rack for balance preset time, and then the balance displacement is moved into the high-precision balance position for weighing m again 3 Up to m 1 And m 3 Is not greater than the preset threshold value, the process is finishedWeighing the blank filter membrane 1 And m 3 The average value of (a) is taken as the weight of the blank filter; the manipulator can be waited to move into the sampling position for sampling process. The blank filter was equilibrated for the purpose of removing water, with the equilibration time specified by relevant environmental standards.
The mechanical arm automatically operates and transfers the filter membrane, and the filter membrane on the balancing stand is correctly transmitted to the balance or the sampling position according to the requirement. The manipulator is controlled by the stepping motor driver, the manipulator is communicated with the balance through the RS232 interface and the environment control unit through a TCP/IP Modbus protocol, various control instructions are completed, data are obtained, and report output is formed. The electric control system schematic is shown in fig. 11. During or before and after the transfer of the filter membrane, the mechanical arm cannot transmit the filter membrane to a designated station according to the requirement to initiate a fault alarm and stop the action of the mechanical arm. The alarm mode includes: the alarm mode can be set and selected by a user in a single or multiple combination mode of sound alarm, luminous flashing alarm, short message alarm and the like.
The weighing of the dust film specifically comprises: the dust film is placed in a balance position of the filter film storage rack through a manipulator, the dust film is balanced for a third preset time period, and the first constant weight of the dust film is achieved at the moment; the dust film is moved into the high-precision balance from the balance position through the mechanical arm, and the dust film is weighed through the high-precision balance to obtain the weight M 1 (ii) a Moving the dust film back to a balance position of the filter film storage rack, balancing the dust film for a fourth preset time period, and then achieving the second constant weight of the dust film; the dust film is moved into the high-precision balance from the balance position through the mechanical arm, and the dust film is weighed again through the high-precision balance to obtain the weight M 2 (ii) a Wherein the fourth preset time period is less than the third preset time period; calculating M of dust film 1 And M 2 Is determined as the difference of (A), M of the dust film is determined 1 And M 2 If the difference is less than the preset threshold, if M of the dust film 1 And M 2 The difference value of the weight difference is not more than a preset threshold value, the weighing of the dust film is finished, and the weight of the dust film is M 1 And M 2 Average value of (d); m if dust film 1 And M 2 If the difference value is larger than the preset threshold value, the dust film is repeatedly moved back to the filterAfter the balance position of the film storage frame is balanced for preset time, the film storage frame is self-balanced and moved into the high-precision balance position for weighing M again 3 Up to M 1 And M 3 The difference value of M is not more than a preset threshold value, the dust film is weighed, and M is added 1 And M 3 As the weight of the dust film; in the process of transferring the blank filter membrane or the dust membrane, when the manipulator cannot convey the blank filter membrane or the dust membrane to a specified station according to requirements, initiating a fault alarm and stopping the action of the manipulator; the alarm mode comprises at least one of the following modes: sound alarm, light flashing alarm and short message alarm.
Preferably, the method further comprises the following steps: and (3) carrying out ion wind static removal on the first dust film after the sampling is finished through the ion wind static removal device, and using the filter membrane subjected to static removal for constant weight and weighing.
Preferably, the vehicle-mounted mobile platform further comprises an upper cabinet and a lower cabinet, the lower cabinet is arranged on the vehicle-mounted mobile platform, and the upper cabinet is arranged on the lower cabinet; the upper cabinet and the lower cabinet are fixedly connected through the steel wire rope damping module, so that impact damage of road surface vibration to system precision parts and interference of micro vibration to measurement in the transportation and transition processes are effectively isolated, the transmission of vibration of the lower cabinet and a vehicle bottom plate is isolated, the flexibility of system installation and movement is improved, and the stability of the device is kept; the lower cabinet is directly fixed on the vehicle bottom plate and the side wall by adopting a vibration-damping rubber pad, and the upper cabinet is connected with the lower cabinet by a vibration damper to isolate the vibration transmission between the environment control system and the automatic sampling _ balance _ measurement system. The damping module comprises a primary damping module, a secondary damping module and a tertiary damping module which are sequentially connected from bottom to top; adopting a three-level vibration reduction module scheme: the primary vibration damping module is a lower cabinet rubber vibration damping pad; the secondary vibration reduction module adopts a steel wire rope vibration absorber to effectively reduce the severe impact on the upper cabinet in the transfer process; the three-level vibration reduction module adopts a miniature silica gel vibration reducer to isolate the influence of micro vibration on the automatic weighing and measuring process. The vibration reduction module is used for isolating vibration out of the upper cabinet; wherein the vibration comprises vehicle body, foundation vibration and vibration caused by gas sampling. A20 mm heat insulation layer polyurethane rigid foam board is adhered on the basis of the main structures of the upper cabinet and the lower cabinet, see table 1, the novel synthetic material with heat insulation and waterproof functions has the heat conductivity coefficient of only 0.022-0.033W/(m × K) and the lowest heat conductivity coefficient.
TABLE 1 polyurethane insulation board Performance parameters
Integrating a mechanical arm and a pipeline device of the sampling module into the upper cabinet; an electric control system and an automatic sampling _ balance _ measurement system (wherein a sampling module only comprises a sampling execution mechanism) are integrated into an upper cabinet, and an environment control module, a negative pressure air source (vacuum pump) of the sampling module and an MFC mass flow controller are integrated into a lower cabinet. And a Beck VT4.4 vacuum pump is adopted, so that the noise is low, the vibration is low, and the influence of the environment is very little. The structure is simple, the maintenance and the repair are simple due to the air cooling mode, and the oil mist separator and other consumables are not required to be replaced for a long time when the lubricating oil is replaced. The sampling position, the balance position, the measurement position and the mechanical arm are observed through an observation window arranged on the side wall of the cabinet body of the upper cabinet. When the road surface is not flat, the vehicle is kept to run normally and stably through the automatic balance adjusting subsystem of the vehicle body; when the driving is stopped, the balance and the stability of the vehicle-mounted mobile platform are kept through adjustment; the automatic balance adjusting subsystem of the vehicle body has a horizontal adjusting function and ensures that a high-precision balance arranged in an instrument in the carriage can be accurately adjusted by 0.
The mobile fine particulate matter online calibration method further comprises the following steps: the environmental control system includes: the temperature and humidity and the air cleanliness of the measuring area are accurately controlled by the electric control unit, the temperature control module, the humidity control module, the air cleaning module and the heat insulation box body; the controlled environment includes: temperature, humidity, cleanliness, wind speed and other parameters. The electric control unit is integrated into the electric control system, and accurate environment control is achieved through touch screen display and operation. The air cleaning module is integrated into the air duct system, and the high cleanliness of the measuring environment is realized by adopting a multi-layer filtering technology. The heat preservation box body adopts an aluminum profile frame, is externally coated with an aluminum plastic plate, and is internally pasted with an aluminum film polyurethane foaming plate to achieve the purpose of isolating the internal and external environments (integrated in the upper cabinet). And partial components of the environment control module and the sampling module are integrated in the lower cabinet. Before the environmental air sample is emitted outwards in two paths in an aerosol mode through the aerosol generator, the internal environment of the upper cabinet is purified for a certain time through the air cleaning module, the concentration of various particles in the internal environment of the upper cabinet is reduced to be below a preset concentration range, and the influence of the particles in the internal environment on a measurement result is reduced. In the online calibration process, the upper cabinet is muted through the static pressure box arranged in the upper cabinet.
The environment monitoring unit is divided into temperature and humidity monitoring. The constant temperature and humidity system 3000W has the functions of dehumidification, humidification, heating and refrigeration. The temperature control firstly reduces the temperature and dehumidifies, and then accurately controls the heating and humidifying to realize the accurate temperature and humidity control in a large temperature and humidity range. The temperature and humidity control device comprises an electric control system, an air duct, a refrigeration/dehumidification unit, a humidification unit and a heating unit. The basic principle is ventilation internal circulation and PID control for temperature and humidity adjustment. Under the condition that the refrigerating/dehumidifying unit continuously works, the electric control system compares the collected temperature/humidity signal in the upper cabinet box with a set value, and the obtained deviation signal is subjected to PID operation to output an adjusting signal and automatically control the output power of the heater and the humidifier, so that the temperature and the humidity in the upper cabinet box are dynamically balanced. The temperature and humidity control schematic diagram of the environment control unit is shown in fig. 9. The temperature control module adopts the refrigeration unit to cool and dehumidify the high-temperature damp and hot air firstly, and then enters the constant-temperature control unit to heat and humidify the high-temperature damp and hot air, so that the performance of the temperature control system is greatly improved. The air heating mode is a high-quality nichrome electric heater; air cooling/dehumidifying manner: a hydrophilic membrane fin tube heat exchanger; in order to ensure that the air speed in the upper cabinet is less than 0.2m/s, the fan is an adjustable air volume fan, and a filter is arranged on an air channel to realize hundred-grade cleanliness of the upper cabinet. A humidifying mode: electric heating type steam humidification; a dehumidification mode: freezing and dehumidifying, and a light pipe surface type dehumidifier. The temperature reduction and dehumidification module is shown in a composition diagram in figure 12. Temperature control range is 15-30 deg.C, temperature control accuracy is + -0.2 deg.C, humidity control range is 40-70%, and humidity is + -2% RH. The temperature is set at 25 deg.C and humidity is set at 50% RH, the instrument is operated for 30min, and the temperature and humidity parameter data is collected every 30min, the temperature change curve of 24h is shown in FIG. 20, and the humidity change curve is shown in FIG. 21. Or within 24h, the average value of temperature control is 24.9 ℃, the temperature change is within the range of +/-1 ℃, and the requirement of the temperature control precision within 24h +/-1 ℃ is met; the average value of the relative humidity control was 49.8%, and the variation was within a range of ± 2.5%. Alternatively, the internal temperature at mooring may be controlled at 25. + -. 3 ℃ and the humidity may be controlled at 50. + -. 15% RH internal environment requirements. The specific operation is as follows: and starting the vehicle-mounted air conditioner, respectively observing temperature and humidity changes within 24 hours in typical environments in 2 seasons of summer and winter, and recording data at intervals of 1 h. The average outdoor temperature in summer is 36.1 ℃, the relative humidity is 79.6%, and the environmental change data in the vehicle-mounted platform are shown in figures 3 and 4. The average outdoor temperature in winter is 9.6 ℃, the relative humidity is 29.6%, and the environment change in the vehicle-mounted platform is shown in figures 5 and 6. The method specifically comprises the following steps: a. a dehumidification system: when the humidity of the air to be regulated is larger than the required value, the compressor is started to refrigerate, and the moisture in the air is separated out to achieve the aim of dehumidification. b. A humidifying system: when the relative humidity of the air to be conditioned is lower than the required value, the constant humidity computer controller enables the electrode type humidifier to work, and the water is heated and boiled into steam which is sent to a room through the fan. c. A heating system: when the temperature of the air to be conditioned is lower than the required temperature, the constant temperature computer controller is connected with the electric heater and is sent to the room to be conditioned through the fan to achieve the purpose of heating. d. A refrigeration system: the compressor compresses the gaseous Freon into high-temperature high-pressure gaseous Freon, and then the gaseous Freon is sent to a condenser (outdoor unit) to be cooled into normal-temperature high-pressure liquid Freon air; the fan of the indoor unit blows the indoor air from the evaporator to lower the indoor temperature. Specifically, the method comprises the following steps: the internal temperature of the upper cabinet is controlled through a temperature control module arranged on the vehicle-mounted mobile platform, the average value of the temperature is controlled within a preset temperature range, and the temperature change is within a range of +/-1 ℃; and controlling the internal humidity of the upper cabinet through a humidity control module arranged on the vehicle-mounted mobile platform, wherein the change of the humidity is within a range of +/-2.5% in a preset average value of relative humidity control. Controlling the environmental temperature and humidity in the platform carriage; the temperature, the humidity and other test environments of the mobile platform can be controlled.
A clean gas source 1 (can be removed) is 80-90L, 980W, and the size of the filter and water removal (molecular sieve or a dryer) is as follows: 520 × 230 × 580mm; the air supply of the environment control unit passes through a flow equalizing pore plate arranged on the side wall of the upper cabinet body, so that the air supply (from a clean air source) of the environment control unit can uniformly flow through the upper cabinet body at a low speed. The structure of the vehicle-mounted fine particle calibration system is schematically shown in figure 2, and the system is light in weight, small in size, modular, standardized and intelligent; portability of transportation and installation of vehicle-mounted equipment; the structure size is small, and the occupied volume in the vehicle is small; grouping the functional units into modules; and (3) standardization: a common device is selected, and the device maintenance and replacement period is shortened; intelligentization: and a perfect operation and protection mechanism prompts operators to intervene and dispose in time when the automatic operation fails. FIG. 18 is a front view, functional in Table 2; controlling the computer to automatically start the system to perform a series of operations; when the motion control system breaks down, pressing down an 'emergency stop' button to immediately stop the motion of the mechanical arm; alarming when various faults occur in the system; when the system starts the temperature and the humidity, bright blue light is generated; the power supply is controlled to be turned on or off and is pressed to be green light. Fig. 19 is a right side view, and the function is shown in table 3. The interface of the water level sensor of the water tank needs to be connected into the system, or the water level sensor cannot operate; the overflow pipe connected with the water tank is far higher than the liquid level.
TABLE 2
| Serial number | Name (R) | Description of the |
| 1 | Control computer | Main human-computer interaction tool of |
| 2 | Damping spring | For supporting upper and lower cabinets and reducing vibration |
| 3 | Emergency stop button | Pressing down in emergency, stopping movement of manipulator |
| 4 | Alarm lamp | Failure of acousto-optic prompt system |
| 5 | Temperature and humidity operating lamp | Bright blue light in humiture operation |
| 6 | Power switch | Controlling the on-off of the main power supply of the equipment |
TABLE 3
| Serial number | Name(s) | Description of the invention |
| 7 | Water filling nozzle | Connecting water injection pipe |
| 8 | Water tank level sensor interface | Please access to monitor the liquid level of the water tank |
| 9 | Overflow gap | Connecting |
| 10 | Water tank | For containing or collecting water entering the apparatus |
Providing a generator and lighting equipment; the arrangement of the roof platform and the rear ladder facilitates the installation and operation of instruments; a fixing device is arranged in the carriage, so that the related instruments and equipment can be conveniently placed and installed. All power was supplied by a generator (removable) with power parameters of 10KW, 220V and dimensions 730 x 610 x 700mm.
The whole framework of the cabinet is built by industrial aluminum profiles, the working cabin is provided with a heat insulation structure, heat conduction of the enclosure structure is reduced, and system power is reduced. The internal size of the vehicle box body is 3X 2.4X 2m (length, width and height), and the rear door is 1000-1200 mm and 2000mm. The box body is made of glass fiber reinforced plastics and engineering plastics. The mobile platform is produced according to the load requirement of the shelter in a customized mode, and the load is 5-7 tons; and accommodates power source accessories such as a suction pump. Examples of internally placed devices are as follows: 1.1 set of gravimetric weighing device: the full power is 1800W, and the full power is 800W when in use; 220V AC/50Hz, size: 860 x 600 x 1680mm, a detection door at the lower left, a rotary operation screen at the upper left, a fixed leveling and vibration reduction function and an outlet at the top of the carriage. 2. Placing 1 BAM1020 type beta ray automatic monitor: the size is 480 x 400 x 400mm 250W 220V, the fixed support is 800-900 mm high (an aluminum alloy section bar frame), and an outlet is arranged on the top of the carriage; 3. place PQ200 particulate matter sampler 1 stage (movable): dimension 470 x 490 x 550mm. 4. Placing the particles to generate uniform mixingDevice 1 set (2 outlets 16.7L,10-10000 ug/m) 3 Static electricity removal and dust generation in the vehicle).
Preferably, the method further comprises the following steps: the gravimetric method standard device is a core component of the fine particulate matter online calibration system and takes PM 2.5 Particulate matter example: drawing a fixed volume of air at a constant rate through the filter with PM 2.5 The sampler of the cutting device can trap atmospheric particles with the kinetic diameter less than 2.5 mu m on the filter membrane with constant weight. And calculating the concentration of atmospheric particulates with kinetic diameters less than or equal to 2.5 μm according to the mass difference of the front and rear filter membranes of the sampler and the sampling volume. The difference between the front and back weighed masses of the blank filter membrane should be much smaller than the particulate matter loading on the sampling filter membrane. The on-line calibration sampling process and the weighing process are integrated, the whole process is unattended, efficient and high-precision, and in the weighing process and the sampling process, the weighing, the flow and the time of collected particles are three major factors influencing the results of the weighing, the flow and the time. First PM 2.5 The reliability and the precision of the weighing result of the particulate matters are main influence factors, and are particularly reflected in the dependence of semi-volatile matters on temperature, the influence of moisture on the weight of the particulate matters, the zero drift of a balance, the influence of static electricity on measurement, the influence of pollutants on a filter membrane in a test and the like; secondly, influencing factors on the sampling flow comprise the influence of temperature and pressure on the flowmeter, the influence of factors such as flow conversion caused by system air leakage and the like; including temporal variations with seasons and the effect of synchronicity of samplers and digital system time on time parameters.
(1) PM 2.5 The weight method ensures that the following steps are carried out: (1) consistency of constant weight of filter membrane and weighing environment: taking the mass difference between the dust film and the blank filter film as PM 2.5 The weighing of the filter membrane comprises the constant weight and the weighing of a blank filter membrane and the constant weight and the weighing of a dust film, so that the influence of factors such as temperature, humidity, atmospheric pressure and the like on the weighing is avoided, and the constant weight and the weighing environment are kept consistent. The blank filter membrane and the dust membrane are both positioned in the constant temperature and humidity system for constant weight, so that the error caused by the environmental difference to the measurement is reduced to the maximum extent. (2) high precision and stability during measurement: the weighing accuracy depends on the accuracy of the balance itself and the stability of the measurement process. The balance loading is automatically completed in the whole process at a stable and slow speed by controlling the mechanical armUnloading and weighing, reducing the influence of vibration and human factors, improving the weighing precision, calibrating the inside of the balance before each measurement, and eliminating the zero drift of the balance to the maximum extent under the condition of ensuring constant temperature and humidity environment. The vehicle-mounted vibration damping device has stable vibration damping design and can also ensure high precision and stability of weighing the blank filter membrane and the dust membrane. The influence of the electrical parameters refers to the influence of the instantaneous pulse voltage or voltage fluctuation change on the balance in the process of operating other electrical components. (3) influence of static electricity on the filter membrane measurements: the filter membrane carries static by friction, humidity low grade factor filter membrane in the sampling, sets up ionic wind and removes electrostatic devices, and the filter membrane sampling finishes and carries out ionic wind through removing electrostatic devices department and remove static, eliminates the influence that static was weighed to the filter membrane. (4) influence of contaminants on the filter membrane: all mechanisms are completely sealed in a constant temperature and humidity system and operated by a full-automatic mechanical arm, so that the fouling of a filter membrane caused by human factors, air convection and the like is eliminated, and the measurement precision is improved. (5) influence of the filter membrane trapping efficiency on the measurement results: the collection efficiency of the filter membrane is one of the important indexes of the filter membrane quality, aiming at PM 2.5 Sampling particulate matters, wherein a filter membrane of the particulate matters sampling device is required to ensure that the filter membrane has the trapping efficiency of more than 99.7 percent for the particulate matters with the particle size of 0.3 mu m. (6) tightness of the sampling system: the processing precision of devices such as the gas circuit and the filter membrane installation is improved, the gas leakage at the gas circuit joint is ensured, the system tightness is reliable, and the measurement accuracy is not influenced. (7) system flow accuracy and stability: the mass flowmeter in a standard state is adopted, so that the precision is high and the stability is good; and air pressure sensors are arranged before and after the filter membrane is sampled to monitor the flow of the membrane pressure before and after the sampling. And a gas balance compensation method is adopted for the vacuum pump at the later stage to avoid sampling flow fluctuation. (8) sampling timing accuracy: the time synchronization and the accurate timing between the system and each component are kept, and the time synchronization requirement of a high-precision timing meter and the accurate calculation of the volume of the sampled gas are met. (9) constant temperature and humidity: water drops can be formed on the wall of the sampling pipe when the humidity of the sampling gas is too high, and the humidity of the sampling gas is removed to ensure that the humidity of the sampling gas does not influence the measurement precision within a required range.
(II) measuring by adopting a vehicle-mounted gravimetric method standard device: guarantee that fine particles gravimetric method standard device operation is reliable, the performance accords with the design index, realizes fine particles gravimetric method automatic measure on predetermineeing the precision.
(1) Balance weighing range: the device adopts a Mettler TOLEDO XP6 high-precision balance (high precision one millionth), the measuring range is 0.001 mg-6.1 g, and the minimum weighing value is 1 mug. In the weighing process, the mass of the weighed object is controlled to be between 0.001g and 0.5g of the balance range, so that the error is reduced.
(2) Balance stability: the high-precision balance is positioned in a constant temperature and humidity box depending on the change of parameters such as static electricity, vibration, airflow disturbance, temperature, humidity and the like, and the temperature and the humidity are kept in a constant range, so the weighing influence of the balance is basically ignored. According to the design characteristics of a base of the instrument and the stability of the device, the vibration damping system can keep the stability of the device, the indication value of the instrument balance is always stabilized at a zero point without contacting or shaking in sampling, and the vibration has no influence on the stability of the balance.
The electric devices operated in the instrument belong to low-power devices, the balance and other parts of the instrument adopt two sets of independent power supply designs for power supply, and the balance has strong voltage stabilization and electric isolation functions. The balance indication value is always stable at zero point and is not influenced by electricity. And the experimental protocol was verified for stability of the balance as follows: the change of the balance zero point is recorded every 1h within 24h as shown in figure 22; placing a balanced PEFT filter membrane on a balance within 24h, and recording the change of the mass of the PEFT filter membrane every 1 h; the data are shown in FIG. 23. From fig. 22 and 23, it can be seen that the device is stable in the range of 0.001g to 0.5g of the usual range of the balance.
(3) The selection and performance of the sampling filters are shown in table 4:
TABLE 4 PM 2.5 Analysis of common Filter Membrane Properties
TeFlon filters are suitable for weighing measurements. The maximum pressure drop of a blank filter (i.e., a clean filter) is one of the main performance parameters of the blank filter, and PM is carried out 2.5 The maximum pressure drop across the blank filter was tested prior to particulate sampling. The pressure drop should be less than 3kPa at a clean air flow rate of 0.45 m/s. Or PM 2.5 The maximum pressure drop of a clean filter of the TeFlon filter was 30cmH at a flow rate of 16.67L/min of clean air 2 The O column is 3kPa. PM (particulate matter) 10 Cutting device and PM 2.5 The cutting device has cutting efficiency, the gas flow passing through the cutter is 16.67L/min, and the maximum pressure drop of the blank filter membrane is not more than 30cmH under the condition that the maximum pressure drop of the blank filter membrane is tested to be 16.67L/min of clean air flow 2 The O column is 3kPa. The measurement device adopted by the maximum pressure drop test of the blank filter membrane under the flow rate of 16.67L/min consists of three parts: filter membrane anchor clamps, flow detection device and pressure measurement. The filter membrane, the filter membrane support and the filter membrane support are combined and installed in the filter membrane clamp, clean and dry air is introduced, and under the condition that the monitoring flow is 16.67L/min, the difference value of the pressure before the membrane and the pressure after the membrane is observed to judge whether the maximum pressure drop of the blank filter membrane meets the standard that the pressure is less than or equal to 3kPa. The blank filter membrane was continuously tested at a flow rate of 16.67L/min for 1min, the average value of the test data was taken as the test result, and the membrane pressure of the blank filter membrane is shown in Table 5.
TABLE 5 Membrane pressure test of TeFlon filters
And (4) carrying out a test by using a related method of the metrological verification regulation of the reference gas sampler for checking the air tightness of the sampling system. And the gas circuit tightness debugging is carried out by adopting a special solid filter membrane component for detecting gas leakage. The solid filter membrane component for detecting air leakage is pressed up to a sampling station under the drive of a manipulator, then a vacuum pump is started to pump air for 10-20 s, when the pressure in front of a flowmeter reaches a certain value, a flow value displayed on an interface is observed, and if the flow is less than 0.5L/min, the air passage of the instrument is normal, the vacuum pump is stopped immediately; and the long-time damage to the gas circuit is avoided, if the flow is more than 0.5L/min, the gas circuit element, the gas pipeline, the vacuum pump and the like are checked to determine the gas leakage reason, wherein the gas leakage condition of the gas circuit of the instrument is indicated. According to the steps above for PM 2.5 The gravimetric standard device adopts a solid filter membrane component, when the vacuum pump pumps air for 10 s-20 s, the pressure before the flowmeter reaches 7.42kPa within 20s, and observation is carried outThe flow of the flowmeter is 0.00L/min, the pressure before the flowmeter is kept unchanged, and the system is proved to have no air leakage and good air tightness.
PM 2.5 PM in sampling process 2.5 The cutter can ensure the cutting efficiency of particles with the kinetic diameter of 2.5 mu m only when the flow rate is 16.67L/min, and the stability of the sampling flow rate is ensured. The sample flow stability test is shown in figure 24. The process is carried out for 24h, data are collected every 20min, the sampling flow control stability is strong, the precision is high, and a test data curve is shown in figure 24.
When measuring aerosol, the automatic mode test is adopted, the automatic program is controlled by a mechanical arm, and 10 mu g/m is measured 3 The test data and calculation process for the left and right aerosols are shown in table 6. The process is as follows: placing the blank filter membrane in a feeding mechanism, and keeping the temperature and humidity constant (25 ℃, 50 percent RH); sampling the flow rate of 16.67L/min, conveying the dust film to a constant weight position, weighing the dust film for the first time after the constant weight, and then weighing the dust film for the second time; respectively calculating the sampled PM according to the average values of the two times of weighing of the blank filter membrane and the sampled dust membrane 2.5 The amount of Particulate Matter (PM) was calculated from the volume of the sampled gas at a flow rate of 16.67L/min 2.5 Concentration values.
TABLE 6 test data
Air buoyancy correction must be performed during the weighing process of the filter membrane to obtain accurate particulate matter mass. And the measuring module is responsible for the management of the electronic balance and the acquisition of weighing data. The balance, the balance frame and the manipulator are interacted to realize full-automatic constant weight and measurement of one batch in the automatic mode, the specific filter membrane needs to be weighed through a software interface in the manual mode, and the weighing flow schematic diagram of the single-dust membrane is shown in figure 16. The electronic balance is corrected and zeroed before weighing. The balance also has an external calibration function when the balance internal calibration sends a balance internal calibration instruction to calibrate the balance under the operation of a user, and the number of external calibration weights is not less than 2; and sending a balance zero setting instruction to automatically zero the balance. The weighing mode (single-sheet and batch weighing) is selected according to actual requirements. Single sheet weighing mode: and selecting the station number of the weighed filter membrane through the window, and automatically conveying the filter membrane of the station number to an electronic balance for weighing. Batch weighing mode: and selecting the station number range of the filter membrane to be weighed through the window, and automatically weighing the filter membrane in the station number range by the system and displaying the time required for weighing the batch of samples.
In the process of weighing the first blank filter membrane and the first dust membrane adopted by the vehicle-mounted gravimetric method standard device, the air buoyancy collected by the high-precision balance is corrected and calibrated by estimating the air density with low precision, and the weight of the blank filter membrane or the dust membrane is obtained according to the corrected and calibrated air buoyancy.
The air buoyancy collected by the high-precision balance is corrected and calibrated, and the weight of a blank filter membrane or dust film is obtained according to the corrected and calibrated air buoyancy, and the method specifically comprises the following steps:
in the weighing measurement of comparing the quality standard, firstly, the air density at the measuring location is obtained, the precision of a thermometer, the precision of an barometer and the precision of a humidity meter which participate in the calculation of the air density determine the precision of the air buoyancy correction, the air density is estimated at low precision by the formula (1), and the air density calibrated by a balance at the measuring location is measured as follows:
wherein: ρ is a unit of a gradient a Air density in g/cm representing balance calibration 3 (ii) a Sufficient significant digits are retained to ensure that the rounding error of the calculated digits is negligible relative to the measurement process. P represents atmospheric pressure in mmHg; reserving effective digits of a preset digit; u represents% relative humidity, and the carry is an integer; reserving effective digits of a preset digit; t represents temperature in units of; reserving effective digits of a preset digit; e.g. of a cylinder s Is 1.3146X 10 9 ×e -5315.56/(t+273.15) 。
For example: the measured values for temperature, humidity and atmospheric pressure were 24.9 c respectively for the vicinity of the high precision balance,49% and 102.3kPa, the calculation results retain 7 significant digits, which can be obtained by the above calculation: ρ =1.189237 × 10 -3 g/cm 3 。
XP6 of METTLER TOLEDO is full-scale electronically controlled, with electronic gain adjusted by known internal standard masses as part of calibration. For example, if the range of electronic control is 100g, a standard weight of 100g is electronically adjusted to produce an indicated accuracy of 100 g. This process effectively embeds an apparent mass inside the balance. The reference density of the apparent mass scale is the density of the standard mass used for calibration, and the reference air density is also the air density at the time of calibration. Then correcting the balance weighing according to the air density calibrated by the balance, and weighing the mass M of the unknown object by the balance x The buoyancy correction formula of (c) is:
M x represents the corrected weight in μ g; m R Represents the balance reading in μ g; rho a Air Density representing balance calibration in g/cm 3 ；ρ c The standard density for calibrating the balance is expressed in g/cm 3 ；ρ x Density in g/cm representing unknown weighed mass 3 。
The high-precision balance comprises an electronic control system and a built-in mass, wherein the balance weight is made of non-magnetic special alloy components and has the density of 8.0g/cm 3 . In the weighing process, the mass (weight) of the blank filter membrane and the weight of the sampled dust membrane need to be weighed, the weight difference is used as the weight of the amount of the particles attached to the sampled filter membrane, aiming at the measurement result of the automatic sampling program shown in the table 6, the weights of the filter membrane before and after sampling are respectively 0.164413g and 0.164652g, and the collected PM is weighed 2.5 The amount of the particulate matter was 239. Mu.g. The balance was internally calibrated at the same temperature, humidity and atmospheric pressure before each weighing. Density of atmospheric particulates the density value of air particulates used herein was 2.25g/cm 3 In this case, the calculation is performed according to: rho a ＝1.189237×10 -3 g/cm 3 ，ρ c ＝8.0g/cm 3 ，M R ＝239μg，ρ x ＝2.25g/cm 3 (ii) a Obtaining: m R =239.09 μ g. The concentration change amount of the buoyancy-corrected water-based fuel is about 0.03% compared with the concentration before and after buoyancy correction. And (3) analyzing according to the formula (2), wherein the larger the difference between the mass density to be measured and the standard density of the calibration balance is, the larger the buoyancy correction data is, and the data is related to the changes of factors such as temperature, humidity and atmospheric pressure.
Preferably, the method further comprises the following steps: calculating the concentration content of the fine particle substances, which specifically comprises the following steps: for the concentration content of the fine particulate matter, the formula (3) is adopted:
wherein: ρ represents the concentration of fine particles in μ g/m 3 ；w 2 Represents the weight of the first dust film in mg; w is a 1 Represents the weight of the blank filter in mg; v represents the standard volume of the ambient air sample, the volume of the ambient air sample entering the vehicle-mounted gravimetric standard device at 0 ℃ and 1 standard atmosphere is m 3 。
The relationship (4) between the constant flow rate Q of the ambient air sample, the sampling time t, and the standard volume V at which the sampled ambient air sample is obtained is shown:
wherein: q, the unit is L/min; t, unit is s.
Substituting the formula (4) into the formula (3) to obtain the concentration formula (5) of the fine particulate matter:
w 1 represents the weight of the blank filter membrane before sampling; w is a 2 The weight of the first filter is indicated.
Preferably, the method further comprises calculating an uncertainty in a concentration measurement of the fine particulate matter as intercepted by a vehicle gravimetric standard; the calculating of the uncertainty of the concentration measurement of the fine particulate matter specifically includes:
the component of uncertainty of concentration measurement of the fine particulate matterThe method comprises the following steps: weighing the introduced uncertainty u (delta), the uncertainty u (Q) introduced by the sampling flow Q of the mass flowmeter, the uncertainty u (t) introduced by the sampling time t and the synthetic uncertainty u (delta) of the concentration measurement value by a high-precision balance c (ρ), the propagation uncertainty U of the concentration measurement, the relative propagation uncertainty U of the concentration measurement rel . The weight of the blank filter is passed through w 1 Denotes the weight of the first dust film passes through w 2 Is shown due to w 1 、w 2 Weighing using the same balance, thus w 1 、w 2 There is a correlation; and (3) obtaining an uncertainty synthetic formula (7) of the fine particle concentration by combining the components of the uncertainty of the measured concentration value of the fine particle substance by using an uncertainty propagation law according to the formula (5):
according to the uncertainty synthesis formula (7), the factors for obtaining the uncertainty related to the weighing of the precision balance comprise: weight measurement w of blank filter membrane before sampling 1 Introduced uncertainty u (w) 1 ) The weight measurement value w of the first dust film after sampling 2 Introduced uncertainty u (w) 2 ) And an input amount w 1 And w 2 Estimate u (w) of covariance 1 ,w 2 )；
Because blank filter membrane and the dust film after the sampling weigh the adoption be same high accuracy balance, establish that measuring high accuracy balance itself has composite error delta, and standard uncertainty is u (delta), then exists: u (w) 1 )＝u(w 2 ) = u (Δ). According to two masses w measured by the same high-precision balance 1 ,w 2 Having a correlation, let w 1 = F (Δ) = a + Δ; wherein A is the weight measurement w of the blank filter 1 The values of (a) are regarded as constants. w is a 2 = G (Δ) = B + Δ; wherein B is a measurement w 2 The values of (a) are regarded as constants. Then the input quantity w 1 ,w 2 The covariance estimate of (a) is:
therefore, u in equation (7) 2 (w 1 )+u 2 (w 2 )+2u(w 1 ,w 2 )＝u 2 (Δ)+u 2 (Δ)+2u 2 (Δ)＝4u 2 (Δ), u (Δ) is the precision balance introduced uncertainty.
Preferably, the uncertainty associated with the high-precision balance weighing comprises the following certainty: uncertainty u introduced by maximum allowable error measured by high-precision balance 1 (Delta) uncertainty u introduced by high-precision balance measurement repeatability 2 (Delta) uncertainty u introduced by high-precision balance measurement value estimation reading 3 (Delta), uncertainty u introduced by buoyancy correction 4 (Delta), uncertainty u introduced by temperature and humidity effects 5 (Delta); wherein:
measuring the maximum allowable error induced uncertainty u for said balance 1 The calculation of (Δ) specifically includes: according to the maximum allowable error in the range of 0.001g-0.5g allowed by the high-precision balance, the uncertainty introduced by the maximum allowable error is calculated according to uniform distribution:
measuring the repeatedly introduced uncertainty u of the high-precision balance 2 The calculation of (Δ) specifically includes: setting the sampling time of a blank filter membrane as 0 by using a fixed blank filter membrane, and circularly repeating blank filter membrane balancing, blank filter membrane weighing, sampling, blank filter membrane balancing and blank filter membrane weighing for 6 times to obtain a standard deviation s; uncertainty u introduced by calculating measurement repeatability of balance 2 (Δ)。
Uncertainty u introduced by estimating and reading measured indication value of the high-precision balance 3 The calculation of (Δ) specifically includes: the high-precision balance is one millionth and one day flat, the minimum division value is 0.001mg, the estimation error is 1/2 division value, and the reliability is 25 percent according to uniform distribution:
uncertainty u introduced when high-precision balance measurement indication is estimated and read 3 (Delta) is far smaller than the uncertainty u introduced by the measurement repeatability of the high-precision balance 2 (Δ), when calculating uncertainty u 3 (Δ) ignoring: u. of 3 (Δ)＝0。
The air buoyancy corrects the introduced uncertainty u 4 The calculation of (Δ) specifically includes: when the fine particulate matter is PM 2.5 Particle, calculating uncertainty introduced by air buoyancy correction 4 (delta) and the uncertainty introduced by the air buoyancy correction is far less than the measurement accuracy requirement, the uncertainty introduced by the air buoyancy correction is u 4 (Δ) ignoring: u. of 4 (Δ)＝0。
Uncertainty u introduced by temperature and humidity influence 5 The calculation of (Δ) specifically includes: the method comprises the steps of calibrating the high-precision balance before the high-precision balance is weighed, weighing the high-precision balance in a short time according with the current temperature reading and humidity conditions, and keeping the high-precision balance in a constant-temperature and constant-humidity environment with the requirement of the environment condition for weighing the high-precision balance all the time in the weighing process, so that the uncertainty u caused by the temperature and the humidity 5 (Δ) is relatively small, ignoring the uncertainty introduced by temperature and humidity: u. u 5 (Δ)＝0。
Measuring the uncertainty u introduced by the maximum allowable error according to a high-precision balance 1 (Delta) measurement of repeatability-induced uncertainty u by high-precision balance 2 (Delta), high precision balance measurement indication estimation induced uncertainty u 3 (Delta), uncertainty u introduced by buoyancy correction 4 (Delta), uncertainty u introduced by temperature and humidity effects 5 (Δ), calculating the uncertainty u (Δ) introduced by the high precision balance as:
preferably, the calculating of the uncertainty u (Q) introduced by the sampling flow rate Q of the mass flowmeter specifically includes:
(1) Maximum allowable induced uncertainty u of flowmeter 1 (Q) introducing according to the maximum flow set by the certificate of certification: u. of 1 (Q) = flow maximum × 0.45%.
(2) Uncertainty u introduced by flow repeatability 2 (Q): the uncertainty introduced by flow repeatability belongs to uncertainty A class evaluation, and an ambient air sample is sampled for 10 times at a constant flow rate of 16.67L/min, wherein the average value of the flow rates of 10 times is
The mean square error of the flow rates for 10 times is s; calculating uncertainty introduced by flow repeatability
(3) Reading-induced uncertainty u is estimated from an indication 3 (Q): uncertainty u introduced by indicating value estimation reading 3 (Q) belongs to uncertainty B type evaluation, according to the minimum division value and the estimated error of the mass flowmeter being 1/2 division value, the reliability is 25% according to uniform distribution:
the uncertainty u (Q) introduced by the sampling flow Q of the mass flowmeter is as follows:
the sampling time adopts accurate synchronous standard time, the error of 24h is less than 1s, and the uncertainty u (t) introduced by the sampling time t is ignored: u (t) =0.
The synthetic uncertainty u of the fine particle concentration measurement c The calculation of (ρ) specifically includes:
according to w 1 ,w 2 Q, t, the synthetic uncertainty u of the concentration measurement is calculated by equation (7) c (ρ)：
The calculation of the extended uncertainty U of the fine particulate matter concentration measurement value specifically includes: standard uncertainty: u = u c (ρ); if k =2, the spread uncertainty of the fine particle concentration measurement is U = U c (ρ)×k。
The relative spread uncertainty U of the fine particle concentration measurements rel The calculation specifically includes: the relative standard uncertainty is: (u) c (ρ)/ρ) × 100%; relative spread uncertainty of concentration measurements
Examples are respectively 10. Mu.g/m 3 、80μg/m 3 、10000μg/m 3 And about three typical concentrations of aerosol.
(1)10μg/m 3 Analysis and calculation of uncertainty of measurement of nearby concentration points
PM 2.5 The concentration content is calculated according to the formula (3):
where ρ represents PM 2.5 Concentration,. Mu.g/m 3 ；w 2 Represents the mass of the filter membrane after sampling, mg; w is a 1 Represents the mass of the filter membrane before sampling, mg; v denotes the sample volume in the standard case, m 3 。
In actual sampling, standard volume V (m) of sampling gas is obtained by controlling standard condition flow Q (L/min) and sampling time t(s) of a mass flowmeter 3 ) The relationship between the three is shown in equation (4):
the formula (4) is substituted into the formula (3) to obtain PM 2.5 The concentration formula is shown as formula (5):
PM 2.5 concentration rho and mass w of filter membrane before and after sampling 1 、w 2 The working condition flow Q, the sampling time t and four variables are related, and the uncertainty propagation law is utilized to carry out the calculation of y = f (x) 1 ,x 2 ,...x i ..x j Account), if x i Only with x j If the other input quantities are not related, the combined uncertainty of the output quantity y and the input quantity x are obtained 1 ,x 2 ,...x i ..x j The standard uncertainty model equation of the intersection is shown as equation (6):
for PM according to equation (6) 2.5 The concentration calculation equation (5) performs an indeterminate analysis due to w 1 、w 2 And (3) weighing by using the same balance, so that correlation exists, and obtaining the uncertainty synthesis formula (7):
synthetic PM is synthesized according to equation (7) 2.5 The main components of the uncertainty of the concentration measurements were analyzed as follows:
1.1 precision balance weighing the incoming uncertainty u (Delta)
According to the uncertainty synthesis formula (7), the uncertainty related to balance weighing mainly comprises three parts which are respectively the measured value w of the blank filter membrane mass before sampling 1 Introduced uncertainty u (w) 1 ) The measured value w of the quality of the filter membrane after sampling 2 Introduced uncertainty u (w) 2 ) And an input amount w 1 And w 2 Estimate u (w) of the covariance 1 ,w 2 ) Because blank filter membrane and the dust film after the sampling weigh the adoption be same balance, establish that there is comprehensive error delta in the precision balance of measurement itself, standard uncertainty is u (delta), then exists: u (w) 1 )＝u(w 2 )＝u(Δ)；
Because the two masses w are measured by adopting the unified balance 1 ,w 2 Generating a correlation, let w 1 = F (Δ) = A + Δ, A is the measurement w 1 Is taken as a constant, w 1 = G (Δ) = B + Δ, B is the measurement w 2 If the indication value of (b) is regarded as a constant, two masses w are measured 1 ,w 2 The covariance estimate of (a) is:
therefore, in equation (7): u. of 2 (w 1 )+u 2 (w 2 )+2u(w 1 ,w 2 )＝u 2 (Δ)+u 2 (Δ)+2u 2 (Δ)＝4u 2 (Δ)。
And (4) analyzing the introduced uncertainty u (delta) of the precision balance according to the result of the precision balance certificate adopted by the measurement.
Firstly, the uncertainty u introduced by the maximum allowable error measured by the balance 1 (Δ)
According to the certificate of balance verification, the maximum allowable error of the balance in the range of 0.001g-0.5g is +/-0.001 mg, the calculation is carried out according to uniform distribution, and the introduced uncertainty is as follows:
secondly, the balance measures the repeatedly introduced uncertainty u 2 (Δ)
In balance repeatability tests, the filter membrane balance-weighing-sampling-balance-weighing test (setting the filter membrane sampling time to 0, i.e. not actually sampled) is repeated 6 times with a fixed membrane to obtain the standard deviation s. Calculating uncertainty u introduced by balance measurement repeatability 2 (Δ)。
The method comprises the following specific steps: and (5) waiting for the experiment after the temperature and the humidity are stable. After the primary balance is finished, the filter membrane is conveyed to the position below the ion fan by the manipulator, the ion wind is continuously blown for 10s, the balance is set to be zero, the filter membrane is conveyed to the balance by the manipulator and then is withdrawn, and the balance door is closed to wait for the balance to be stable. Then the mechanical arm takes out the filter membrane and puts back the filter membrane frame for balancing again. After the balance is finished, the mechanical arm grabs the filter membrane and sends the filter membrane to the position below the ion fan, the ion wind is continuously blown for 10s, then the balance is set to zero, the mechanical arm sends the filter membrane into the balance and then quits, and the balance door is closed to wait for the balance to be stable. And taking out the filter membrane by a mechanical arm, putting the filter membrane into a sampling position, and sampling. After sampling, the mechanical arm takes back the filter membrane, and the filter membrane is placed in a filter membrane frame to wait for primary balance after sampling. After the primary balance is completed, the mechanical arm sends the filter membrane to the position below the ion fan, the ion wind is continuously blown for 10s, then the balance is set to be zero, the mechanical arm sends the filter membrane to the balance and then quits, and the balance door is closed to wait for the balance to be stable to obtain first data after sampling. Then the mechanical arm takes out the filter membrane and puts back the filter membrane frame for balancing again. After the balance is completed again, the mechanical arm grabs the filter membrane and sends the filter membrane to the position below the ion fan, the ion wind is continuously blown for 10s, then the balance is set to zero, the mechanical arm sends the filter membrane to the balance and then withdraws, the balance door is closed for waiting for the balance to be stable, and the second data after sampling is obtained, and the average value m1 of the first data and the second data after sampling is recorded at the moment and is used as the first data of the repeated experiment. The filter membrane was removed and returned to the filter membrane rack, which was then cycled 6 times. The test data and results are shown in Table 7.
TABLE 7 record of the repeatability tests
Thirdly, the uncertainty u introduced by the scale measurement indicating value estimation reading 3 (Δ): the precision balance is one millionth and one day flat, the minimum division value is 0.001mg, the estimation error is 1/2 division value, and the precision balance is uniformly distributed with the reliability of 25 percent:
reading-induced uncertainty u is estimated from an indication 3 (Delta) is far less than the uncertainty u introduced by the balance measurement repeatability 2 (Δ), so u 3 (Δ) can be ignored in the calculation.
Fourthly, uncertainty u introduced by buoyancy correction 4 (Δ): air buoyancy correction is for PM that weighs 2.5 Of particulate matter, buoyancy-corrected induced uncertainty relative to measurement processThe accuracy is negligible: u. of 4 (Δ)＝0。
Fifthly, uncertainty u introduced by temperature and humidity influence 5 (Δ): before the balance is weighed, at first carry out inside calibration, carry out the short time to weighing under the temperature, the humidity situation of measurement calibration under the current situation and weigh to in the balance is in constant temperature and humidity environment all the time, the control condition of humiture requires rigorously, accords with the environmental condition requirement that precision balance weighed, so the uncertainty that is brought by the humiture is smaller, can ignore: u. of 5 (Δ) =0. According to the above analysis, the uncertainty u (Δ) introduced by the precision balance is:
1.2 uncertainty u (Q) introduced by sampling flow Q of mass flowmeter
First, the maximum allowable induced uncertainty u of the flow meter 1 (Q): according to the verification certificate, the uncertainty of the verification result of the flowmeter is introduced according to the maximum value: u. of 1 (Q)＝16.67L/min×0.45％＝0.075L/min。
Second, uncertainty u introduced by flow repeatability 2 (Q): the method belongs to the uncertainty A-type evaluation, and the flow of a sampling point is tested for 10 times according to 16.67L/min, and the measured flow value is as follows, and the unit is L/min;
the average value is:
the mean square error is: s =0.0082L/min;
third, the reading of the indication value is introducedUncertainty u 3 (Q): and the method belongs to uncertainty B evaluation: the minimum division value of the mass flowmeter is 0.01L/min, the estimation error is 1/2 division value, the measurement error is uniformly distributed, and the reliability is 25%:
therefore, the number of the first and second electrodes is increased,
1.3 uncertainty introduced by sampling time t u (t): the sampling time adopts accurate synchronous standard time, the error of 24h is less than 1s, and the uncertainty introduced by the sampling time can be ignored: u (t) =0.
1.4 PM 2.5 Synthetic uncertainty u of concentration measurements c (ρ)
For a set of test data, the data for the automatic measurement process is shown in Table 8, where w 1 ,w 2 And taking the measured mean value of Q and t, and calculating the introduced uncertainty.
TABLE 8 PM 2.5 Measurement data
| Measurement item | w 1 (mg) | w 2 (mg) | Q(L/min) | t(s) |
| Mean value of measured values | 0.164413 | 0.164652 | 16.67 | 86400 |
The concentration measured at this time was ρ =9.956 μ g/m 3 ；u(Δ)＝0.0055mg，u(Q)＝0.075L/min
The uncertainty of the concentration is obtained according to equation (7):
1.4 PM 2.5 extended uncertainty U of concentration measurement
Standard uncertainty: u = 0.46. Mu.g/m 3 (ii) a If k =2, the expansion uncertainty is U =0.92 μ g/m 3 。
1.6 PM 2.5 Uncertainty U of relative spread of concentration measurements rel
Therefore in the primary PM 2.5 In a typical measurement procedure, the relative standard uncertainty: (046. Mu.g/m) 3 /9.956μg/m 3 ) X 100% =4.7%; relative expansion uncertainty:
(2)80μg/m 3 near concentration point measurement uncertainty analysis
Precision balance weighing the incoming uncertainty u (Δ): u (Δ) =0.0055mg; uncertainty u (Q) introduced by mass flowmeter sampling flow Q: u (Q) =0.075L/min; uncertainty introduced by sampling time t u (t): u (t) =0;
PM 2.5 synthetic uncertainty u of concentration measurements c (ρ) the following is the data for the measurement procedure for a set of test data, table 9, where w 1 ,w 2 And Q, t, taking the measured mean value, and calculating the introduced uncertainty.
TABLE 9 PM 2.5 Measurement data
| Measuring item | w 1 (mg) | w 2 (mg) | Q(L/min) | t(s) |
| Mean value of measured values | 0.163937 | 0.165859 | 16.67 | 86400 |
The concentration measured at this time was ρ =80.07 μ g/m 3 ；u(Δ)＝0.0055mg，u(Q)＝0.075L/min
The uncertainty of the concentration is obtained according to equation (7):
PM 2.5 extended uncertainty U of concentration measurements, wherein standard uncertainty: u = 0.59. Mu.g/m 3 (ii) a If k =2, the expansion uncertainty is U =1.18 μ g/m 3 ；
PM 2.5 Uncertainty U of relative spread of concentration measurements rel (ii) a Relative standard uncertainty: (0.59. Mu.g/m) 3 /80.07μg/m 3 ) X 100% =0.74%; relative expansion uncertainty:
(3)10000μg/m 3 near concentration point measurement uncertainty analysis precision balance weighing the incoming uncertainty u (Δ): u (Δ) =0.0055mg;
uncertainty u (Q) introduced by mass flowmeter sampling flow Q: u (Q) =0.075L/min; uncertainty introduced by sampling time t u (t): u (t) =0;
PM 2.5 synthetic uncertainty u of concentration measurements c (ρ) for a set of test data, the data for the measurement process is shown in Table 10, where w 1 ,w 2 Q, t is taken as the mean value, at which the measured concentration is ρ = 10021.04. Mu.g/m 3 (ii) a u (Δ) =0.0055mg, u (Q) =0.075L/min, the introduced uncertainty is calculated.
TABLE 10 PM 2.5 Measurement data
| Measurement item | w 1 (mg) | w 2 (mg) | Q(L/min) | t(s) |
| Mean value of measured values | 0.164179 | 0.404732 | 16.67 | 86400 |
The uncertainty of the concentration is obtained according to equation (7):
PM 2.5 spread uncertainty of concentration measurement U: standard uncertainty: u = 45.09. Mu.g/m 3 (ii) a If k =2, the expansion uncertainty is U =90.18 μ g/m 3 ；
PM 2.5 Uncertainty U of relative spread of concentration measurements rel Relative standard uncertainty: (45.09. Mu.g/m) 3 /10021.04μg/m 3 ) X 100% =0.5%; relative expansion uncertainty:
k＝2。
to sum up, on-vehicle fine particles online calibration device, gas collection colloidal sol particle generator, on-vehicle moving platform and on-vehicle weight method standard device in an organic whole. Aerosol mass concentration generation range (10-10000) mu g/m 3 The device is suitable for the research work of the particulate matter measuring device; a plurality of technical standards for atmospheric fine particle concentration gravimetric method measurement at home and abroad are taken, the strictest control parameters are taken, an upper and lower split type structure is adopted for a fine particle concentration gravimetric method standard device, an electric control system and an automatic sampling _ balance _ measurement system (wherein a sampling module only comprises a sampling execution mechanism) are integrated into an upper cabinet, an environment control module, a sampling module negative pressure air source and an MFC (mass flow controller) are integrated into a lower cabinet, the upper cabinet and the lower cabinet are connected and fixed through a steel wire rope shock absorber, the vibration transmission of the lower cabinet and a vehicle bottom plate is effectively isolated, meanwhile, the flexibility of system installation and movement is improved, intercommunication and ventilation are realized, compared with the traditional gravimetric method (manual detection method), the vehicle-mounted gravimetric method standard device integrates a plurality of functions such as a precision weighing balance, a constant temperature and humidity control system and an automatic detection device, constant weight and weighing are directly carried out after the sampling of a filter membrane, links such as filter membrane transfer and independent room establishment can be automatically realized, and fine particle concentration gravimetric method-based on the gravimetric method can be realizedThe whole process of concentration measurement can be unattended in the whole process, errors caused by filter membrane transfer, human factors and the like are reduced, the measurement precision is improved, the measurement time is saved, and the efficiency is improved. And the stability and high accuracy of the measuring process are ensured. The measurement range of the fine particle online calibration device is as follows: (10-10000) mu g/m 3 The relative standard uncertainty of the measurement result is (4.7-0.5)%, k =2, the requirement is met, and the PM is met 2.5 The on-site online calibration comparison requirements of the measuring instrument have profound significance for promoting national science and technology, economic and social development and high-tech application.
It should be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented. In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. To those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or". The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The on-line calibration method of the mobile fine particulate matter is characterized in that the on-line calibration system of the mobile fine particulate matter monitor is adopted for implementation, and the on-line calibration system of the mobile fine particulate matter monitor comprises the following steps: the system comprises a vehicle-mounted mobile platform, a vehicle-mounted gravimetric method standard device and an aerosol generator, wherein the vehicle-mounted gravimetric method standard device and the aerosol generator are arranged on the vehicle-mounted mobile platform; calibrating the fine particle monitoring instrument on line by using the mobile fine particle monitoring instrument on-line calibration system;
the mobile fine particulate matter online calibration method comprises the following steps:
moving the mobile fine particulate matter monitor online calibration system to a working place where the calibrated fine particulate matter monitor is located;
placing a vehicle-mounted gravimetric method standard device and a fine particle monitoring instrument at a close space position in a vehicle-mounted mobile platform;
setting relevant parameters of a vehicle-mounted gravimetric method standard device, setting relevant parameters of a fine particulate matter monitoring instrument, and starting the gravimetric method standard device and the calibrated fine particulate matter monitoring instrument at the same time;
an aerosol generator is used for dividing an ambient air sample into two paths in an aerosol form and emitting the two paths outwards at the same constant flow rate, the first path of aerosol is emitted to a vehicle-mounted gravimetric method standard device, and the second path of aerosol is emitted to a fine particulate matter monitoring instrument;
the vehicle-mounted gravimetric method standard device receives the first path of aerosol through the first blank filter membrane to obtain a first dust film, calculates the mass concentration of fine particles in an ambient air sample according to the first dust film, and records the mass concentration as a first concentration value;
the fine particle monitor receives the second path of aerosol through the second blank filter membrane to obtain a second dust film, and calculates a fine particle mass concentration value in the ambient air sample according to the second dust film, and records the fine particle mass concentration value as a second concentration value; wherein, the sampling and measuring time of the aerosol by the vehicle-mounted gravimetric method standard device and the fine particulate matter monitoring instrument is the same;
and comparing the first concentration value with the second concentration value, carrying out online calibration on the fine particulate matter monitoring instrument according to a comparison result, and calibrating the detection precision of the fine particulate matter monitoring instrument on the fine particulate matter to be within a preset range.
2. The on-line calibration method for moving fine particulate matters according to claim 1, wherein the vehicle-mounted gravimetric standard device comprises a sampling module, a balancing module and a measuring module;
the vehicle-mounted gravimetric method standard device receives a first path of aerosol through a first blank filter membrane, calculates the mass concentration of fine particles in an ambient air sample according to a first dust membrane, and records the mass concentration as a first concentration value, and specifically comprises:
the first path of aerosol firstly enters a sampling module of a vehicle-mounted gravimetric method standard device at a constant flow, and reaches a first blank filter membrane after sequentially passing through a cutter and a pipeline device in the sampling module; classifying the fine particles of the environmental air sample according to the diameter size by a cutter, and passing through a corresponding first blank filter membrane while classifying; the first blank filter membrane acquires fine particles of corresponding levels to finish sampling of an ambient air sample; meanwhile, the vacuum pump adopts a gas balance compensation method to avoid sampling flow fluctuation; wherein the grade of the fine particles obtained by the first blank filter membrane is the same as the grade of the fine particles obtained by the fine particle detection instrument;
the flow of the sampling pipeline is reduced due to the increase of the resistance of the filter membrane along with the advance of time in the process of sampling the ambient air sample, the instantaneous flow of the ambient air sample at the filter membrane is collected through the mass flow sensor, the electromagnetic proportional valve is controlled through the PID circuit according to the instantaneous flow based on the fuzzy PID control algorithm of the BP neural network to adjust the instantaneous flow of the first air inlet, the flow change caused by the increase of the resistance of the filter membrane is corrected in real time, and the constant flow in the sampling pipeline is ensured; or alternatively
Installing air pressure sensors in front of and behind the filter membrane in the flow direction of the ambient air sample, and monitoring the filter membrane pressure before and after sampling in real time through the air pressure sensors; the temperature and the humidity of the gas in the space where the vehicle-mounted gravimetric method standard device is located are collected in real time through a temperature and humidity sensor, and compensation calculation of the pressure, the temperature and the humidity is carried out on the gas in the space where the vehicle-mounted gravimetric method standard device is located according to an ideal gas state calculation formula, so that the purpose of accurately controlling the flow in the sampling pipeline to be constant is achieved;
various data generated during the on-line calibration process are viewed through the flow control panel.
3. The on-line calibration method for moving fine particulate matter according to claim 2, further comprising:
before the environmental air sample is emitted outwards in the aerosol form at the same constant flow rate in two paths through the aerosol generator, weighing a first blank filter membrane required by the vehicle-mounted gravimetric method standard device and a second blank filter membrane required by the fine particulate matter monitor respectively;
weighing the first dust film after the first dust film is obtained to obtain the weight of the first dust film, and taking the difference between the weight of the first dust film and the weight of the first blank filter membrane as the first weight of fine particles attached to the first blank dust film;
weighing the second dust film after the second dust film is obtained to obtain the weight of the second dust film, and taking the difference between the weight of the second dust film and the weight of the second blank filter film as the second weight of the fine particles attached to the second blank dust film;
wherein, weighing blank filter membrane specifically includes:
putting the blank filter membrane into a balance position of a filter membrane storage rack through a manipulator, balancing the blank filter membrane for a first preset time period, and then achieving the first constant weight of the blank filter membrane; the blank filter membrane is moved into a high-precision balance from the balance position through a manipulator, and the blank filter membrane is weighed through the high-precision balance to obtain the weight m 1 (ii) a The manipulator is a cylindrical coordinate type robot, the cylindrical coordinate type robot does not have an X-axis track and has a Z axis with preset intensity, and the operation track of the cylindrical coordinate type robot is in fan-shaped motion and lifting motion rotating around the circle center;
moving the blank filter membrane back to the balance position of the filter membrane storage rack, balancing the blank filter membrane for a second preset time period, and then reaching the second constant weight of the blank filter membrane; the blank filter membrane is moved into the high-precision balance from the balance position through the manipulator, and the blank filter membrane is weighed again through the high-precision balance to obtain the weight m 2 (ii) a Wherein the second preset time period is less than the first preset time period;
calculate m for blank Filter 1 And m 2 M of the blank filter membrane is judged 1 And m 2 Is less than a predetermined threshold value, if m of the blank filter membrane is less than m 1 And m 2 The difference value of (A) is not more than a preset threshold value, the weighing of the blank filter membrane is completed, and the weight of the blank filter membrane is m 1 And m 2 Average value of (d); if m of blank filter 1 And m 2 If the difference value is larger than the preset threshold value, the blank filter membrane is repeatedly moved back to the balance position of the filter membrane storage rack for balance preset time, and then the balance displacement is moved into the high-precision balance position for weighing m again 3 Up to m 1 And m 3 Difference of (2)Not more than a preset threshold value, finishing weighing the blank filter membrane, and mixing m 1 And m 3 The average value of (a) is taken as the weight of the blank filter;
the weighing of the dust film specifically comprises:
the dust film is placed in a balance position of the filter film storage rack through a manipulator, the dust film is balanced for a third preset time period, and the first constant weight of the dust film is achieved at the moment; the dust film is moved into the high-precision balance from the balance position through the mechanical arm, and the dust film is weighed through the high-precision balance to obtain the weight M 1 ；
Moving the dust film back to a balance position of the filter film storage rack, balancing the dust film for a fourth preset time period, and then achieving the second constant weight of the dust film; the dust film is moved into the high-precision balance from the balance position through the mechanical arm, and the dust film is weighed again through the high-precision balance to obtain the weight M 2 (ii) a Wherein the fourth preset time period is less than the third preset time period;
calculating M of dust film 1 And M 2 Is determined as the difference of (A), M of the dust film is determined 1 And M 2 If the difference is less than the preset threshold value, if M of the dust film 1 And M 2 The difference value of the weight difference is not more than a preset threshold value, the weighing of the dust film is finished, and the weight of the dust film is M 1 And M 2 Average value of (d); m if dust film 1 And M 2 If the difference value is larger than the preset threshold value, the dust film is repeatedly moved back to the balance position of the filter membrane storage rack for balance preset time, and then the self-balance displacement is moved to the high-precision balance position for weighing M again 3 Up to M 1 And M 3 The difference value of M is not more than a preset threshold value, the dust film is weighed, and M is added 1 And M 3 As the weight of the dust film;
in the process of transferring the blank filter membrane or the dust membrane, when the manipulator cannot convey the blank filter membrane or the dust membrane to a specified station according to requirements, initiating a fault alarm and stopping the action of the manipulator; the alarm mode comprises at least one of the following modes: sound alarm, light flashing alarm and short message alarm.
4. The method for on-line calibration of mobile fine particulate matter of claim 3, further comprising:
and (3) carrying out ion wind static removal on the first dust film after the sampling is finished through the ion wind static removal device, and using the filter membrane subjected to static removal for constant weight and weighing.
5. The on-line calibration method for mobile fine particulate matter according to claim 2, wherein the vehicle-mounted mobile platform further comprises an upper cabinet and a lower cabinet, the lower cabinet is placed on the vehicle-mounted mobile platform, and the upper cabinet is placed on the lower cabinet; the upper cabinet and the lower cabinet are fixedly connected through a damping module; the damping module comprises a primary damping module, a secondary damping module and a tertiary damping module which are sequentially connected from bottom to top; the vibration reduction module is used for isolating vibration out of the upper cabinet; wherein the vibration comprises vehicle body, foundation vibration and vibration caused during gas sampling;
integrating a mechanical arm and a pipeline device of the sampling module into the upper cabinet; integrating a vacuum pump and a mass flow controller of a sampling module into a lower cabinet;
observing each sampling position, each balance position, each measuring position and each manipulator through an observation window arranged on the side wall of the upper cabinet body;
when the road surface is not flat, the vehicle is kept to run normally and stably through the automatic balance adjusting subsystem of the vehicle body; when the driving is stopped, the balance and the stability of the vehicle-mounted mobile platform are kept through adjustment;
the mobile fine particulate matter online calibration method further comprises the following steps:
before the environmental air sample is emitted outwards in two paths in an aerosol mode through the aerosol generator, the internal environment of the upper cabinet is purified for a certain time through the air cleaning module, the concentration of various particulate matters in the internal environment of the upper cabinet is reduced to be below a preset concentration range, and the influence of the particulate matters in the internal environment on a measurement result is reduced;
in the online calibration process, muting the upper cabinet through a static pressure box arranged in the upper cabinet; and
the internal temperature of the upper cabinet is controlled through a temperature control module arranged on the vehicle-mounted mobile platform, the average value of the temperature is controlled within a preset temperature range, and the temperature change is within a range of +/-1 ℃; and
the internal humidity of the upper cabinet is controlled through a humidity control module arranged on the vehicle-mounted mobile platform, and the change of the humidity is within the range of +/-2.5% within a preset average value of the relative humidity control;
the air supply of the environment control unit passes through a flow equalizing pore plate arranged on the side wall of the upper cabinet body, so that the condition that the air supply of the environment control unit flows through the upper cabinet body at a low speed is ensured.
6. The on-line calibration method for moving fine particulate matter according to claim 3, further comprising:
in the process of weighing a first blank filter membrane and a first dust membrane adopted by a vehicle-mounted gravimetric method standard device, correcting and calibrating the air buoyancy collected by a high-precision balance by estimating the air density with low precision, and obtaining the weight of the blank filter membrane or the dust membrane according to the corrected air buoyancy;
the air buoyancy collected by the high-precision balance is corrected and calibrated, and the weight of a blank filter membrane or a dust membrane is obtained according to the corrected and calibrated air buoyancy, and the method specifically comprises the following steps:
firstly, obtaining the air density at the measuring location, determining the precision of air buoyancy correction according to the precision of a thermometer, the precision of an barometer and the precision of a hygrometer participating in air density calculation, and estimating the air density at low precision according to formula (1), wherein the air density calibrated by a balance at the measuring location is as follows:
wherein:
ρ a air density in g/cm representing balance calibration 3 ；
P represents atmospheric pressure in mmHg; reserving effective digits of preset digits;
u represents% relative humidity, and the carry is an integer; reserving effective digits of preset digits;
t represents temperature in units of; reserving effective digits of preset digits;
e s is 1.3146 × 10 9 ×e -5315.56/(t+273.15) ；
Then correcting the balance weighing according to the air density calibrated by the balance, and weighing the mass M of the unknown object by the balance x The buoyancy correction equation is:
wherein:
M x represents the corrected weight in μ g;
M R represents the balance reading in μ g;
ρ a air Density, expressed in g/cm, for balance calibration 3 ；
ρ c The standard density for calibrating the balance is expressed in g/cm 3 ；
ρ x Density in g/cm representing unknown weighed mass 3 。
7. The on-line calibration method for moving fine particulate matter according to claim 1, further comprising: calculating the concentration content of the fine particulate matter; the calculating of the concentration content of the fine particulate matter specifically includes:
regarding the concentration content of the fine particulate matter, the formula (3) is adopted:
wherein:
ρ represents the concentration of fine particles in μ g/m 3 ；
w 2 Represents the weight of the first dust filmThe bit is mg;
w 1 represents the weight of the blank filter in mg;
v represents the standard volume of the ambient air sample, the volume of the ambient air sample entering the vehicle-mounted gravimetric standard device at 0 ℃ and 1 standard atmosphere, and the unit is m 3 ；
The relationship (4) between the constant flow rate Q of the ambient air sample, the sampling time t, and the standard volume V at which the sampled ambient air sample is obtained is shown:
wherein:
q, the unit is L/min;
t, in units of s;
the concentration of the fine particulate matter is obtained by substituting equation (4) into equation (3) and is expressed by equation (5):
wherein:
w 1 represents the weight of the blank filter membrane before sampling;
w 2 the weight of the first filter after sampling is indicated.
8. The method for on-line calibration of mobile fine particulate matter of claim 7, further comprising:
calculating the uncertainty of the concentration measurement value of the fine particulate matter intercepted by a vehicle-mounted gravimetric method standard device; the calculating of the uncertainty of the concentration measurement of the fine particulate matter specifically includes:
the factors that contribute to the uncertainty of the concentration measurement of the fine particulate matter include: weighing the introduced uncertainty u (delta), the uncertainty u (Q) introduced by the sampling flow Q of the mass flowmeter, the uncertainty u (t) introduced by the sampling time t and the concentration measured value by a high-precision balanceSynthetic uncertainty u of c (ρ), the propagation uncertainty U of the concentration measurement, the relative propagation uncertainty U of the concentration measurement rel ；
The weight of the blank filter is passed through w 1 Denotes the weight of the first dust film passes through w 2 Is shown due to w 1 、w 2 Weighing using the same balance, thus w 1 、w 2 There is a correlation; and (3) according to the concentration formula (5) of the fine particle substances, combining the components of the uncertainty of the concentration measurement value of the fine particle substances by using an uncertainty propagation law, and obtaining an uncertainty synthetic formula (7) of the concentration of the fine particles:
according to the uncertainty synthesis formula (7), the factors for obtaining the uncertainty related to the weighing of the precision balance comprise: weight measurement w of blank filter membrane before sampling 1 Introduced uncertainty u (w) 1 ) And the weight measurement value w of the first dust film after sampling 2 Introduced uncertainty u (w) 2 ) And an input amount w 1 And w 2 Estimate u (w) of covariance 1 ,w 2 )；
Because blank filter membrane and the dust film after the sampling weigh the adoption be same high accuracy balance, establish that measuring high accuracy balance itself has composite error delta, and standard uncertainty is u (delta), then exists: u (w) 1 )＝u(w 2 )＝u(Δ)；
According to two masses w measured by the same high-precision balance 1 ,w 2 Having a correlation, let w 1 F (Δ) = a + Δ; wherein A is the weight measurement w of the blank filter 1 Is regarded as a constant;
w 2 g (Δ) = B + Δ; wherein B is a measure of w 2 Is regarded as a constant;
then the input quantity w 1 ,w 2 The covariance estimate of (a) is:
therefore, u in equation (7) 2 (w 1 )+u 2 (w 2 )+2u(w 1 ,w 2 )＝u 2 (Δ)+u 2 (Δ)+2u 2 (Δ)＝4u 2 (Δ)
u (Δ) is the uncertainty introduced by the precision balance.
9. The method for on-line calibration of mobile fine particulate matter of claim 8, wherein the uncertainty associated with the high precision balance weighing comprises the following determinations: uncertainty u introduced by maximum allowable error measured by high-precision balance 1 (Delta) uncertainty u introduced by high-precision balance measurement repeatability 2 (Delta), high precision balance measurement indication estimation induced uncertainty u 3 (Delta), uncertainty u introduced by buoyancy correction 4 (Delta), uncertainty u introduced by temperature and humidity effects 5 (Delta); wherein:
measuring the maximum allowable error-induced uncertainty u for said balance 1 The calculation of (Δ) specifically includes:
according to the maximum allowable error in the range of 0.001g-0.5g allowed by the high-precision balance, the uncertainty introduced by the maximum allowable error is calculated according to uniform distribution:
repeatedly introduced uncertainty u for the measurement of the high-precision balance 2 The calculation of (Δ) specifically includes:
setting the sampling time of a blank filter membrane to be 0 by using a fixed blank filter membrane, and circularly repeating blank filter membrane balancing, blank filter membrane weighing, sampling, blank filter membrane balancing and blank filter membrane weighing for 6 times to obtain a standard deviation s; calculating uncertainty u introduced by balance measurement repeatability 2 (Δ)；
Estimating and reading the measured indication value of the high-precision balanceUncertainty u of entry 3 The calculation of (Δ) specifically includes:
the high-precision balance is one millionth and one day flat, the minimum division value is 0.001mg, the estimation error is 1/2 division value, and the reliability is 25 percent according to uniform distribution:
uncertainty u introduced when high-precision balance measurement indication is estimated and read 3 (Delta) is far smaller than the uncertainty u introduced by the measurement repeatability of the high-precision balance 2 (Δ), when calculating uncertainty u 3 (Δ) ignoring:
u 3 (Δ)＝0
the air buoyancy corrects for the introduced uncertainty u 4 The calculation of (Δ) specifically includes:
when the fine particulate matter is PM 2.5 Particle, calculating uncertainty u introduced by air buoyancy correction 4 (delta) and the uncertainty introduced by the air buoyancy correction is far smaller than the measurement accuracy requirement, the uncertainty introduced by the air buoyancy correction is u 4 (Δ) ignoring:
u 4 (Δ)＝0
uncertainty u introduced by temperature and humidity influence 5 The calculation of (Δ) specifically includes:
the method comprises the steps of calibrating the high-precision balance before the high-precision balance is weighed, weighing the high-precision balance in a short time according with the current temperature reading and humidity conditions, and keeping the high-precision balance in a constant-temperature and constant-humidity environment with the requirement of the environment condition for weighing the high-precision balance all the time in the weighing process, so that the uncertainty u caused by the temperature and the humidity 5 (Δ) is relatively small, ignoring the uncertainty introduced by temperature and humidity:
u 5 (Δ)＝0
measuring the uncertainty u introduced by the maximum allowable error according to a high-precision balance 1 (Delta) measurement of repeatability-induced uncertainty u by high-precision balance 2 (Delta), high precision balance measurement indication estimation induced uncertainty u 3 (Delta) buoyancy correctionIntroduced uncertainty u 4 (Delta), uncertainty u introduced by temperature and humidity effects 5 (Δ), calculating the uncertainty u (Δ) introduced by the high precision balance as:
10. the method for on-line calibration of moving fine particulate matter according to claim 8, wherein the calculating of the uncertainty u (Q) introduced by the sampling flow Q of the mass flow meter specifically comprises:
(1) Maximum allowable induced uncertainty u of flowmeter 1 (Q) introducing according to the maximum flow set by the certificate of certification: u. of 1 (Q) = flow max × 0.45%
(2) Uncertainty u introduced by flow repeatability 2 (Q)
The uncertainty introduced by flow repeatability belongs to uncertainty A class evaluation, and an ambient air sample is sampled for 10 times at a constant flow rate of 16.67L/min, wherein the average value of the flow rates of 10 times is
The mean square error of the flow rates for 10 times is s; calculating uncertainty u introduced by flow repeatability 2 (Q)：
(3) Reading-induced uncertainty u is estimated from an indication 3 (Q)
Uncertainty u introduced by indicating value estimation reading 3 (Q) belongs to uncertainty B type evaluation, according to the minimum division value and the estimated error of the mass flowmeter being 1/2 division value, the reliability is 25% according to uniform distribution:
the uncertainty u (Q) introduced by the sampling flow Q of the mass flowmeter is as follows:
the sampling time adopts accurate synchronous standard time, the error of 24h is less than 1s, and the uncertainty u (t) introduced by the sampling time t is ignored: u (t) =0;
the synthetic uncertainty u of the fine particle concentration measurement c The calculation of (ρ) specifically includes:
according to w 1 ,w 2 Q, t, the respective means, the resultant uncertainty u of the concentration measurement is calculated by equation (7) c (ρ)：
The calculation of the expansion uncertainty U of the fine particulate matter concentration measurement specifically includes:
standard uncertainty: u = u c (ρ); if k =2, the propagation uncertainty of the fine particle concentration measurement is:
U＝u c (ρ)×k
the relative expansion uncertainty U of the fine particle concentration measurement rel The calculation specifically includes:
the relative standard uncertainty is: (u) c (ρ)/ρ)×100％
Uncertainty U of relative spread of concentration measurements rel ：
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116879121A (en) * | 2023-09-08 | 2023-10-13 | 深圳市潼芯传感科技有限公司 | Air particulate matter concentration real-time monitoring system based on optical fiber sensing technology |
| CN117054305A (en) * | 2023-10-11 | 2023-11-14 | 广东盈峰科技有限公司 | Monitor, calibration method and device thereof and storage medium |
| CN117647300A (en) * | 2024-01-30 | 2024-03-05 | 浙江大学 | CVD online in-situ weighing system and method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116879121A (en) * | 2023-09-08 | 2023-10-13 | 深圳市潼芯传感科技有限公司 | Air particulate matter concentration real-time monitoring system based on optical fiber sensing technology |
| CN116879121B (en) * | 2023-09-08 | 2023-11-10 | 深圳市潼芯传感科技有限公司 | Air particulate matter concentration real-time monitoring system based on optical fiber sensing technology |
| CN117054305A (en) * | 2023-10-11 | 2023-11-14 | 广东盈峰科技有限公司 | Monitor, calibration method and device thereof and storage medium |
| CN117054305B (en) * | 2023-10-11 | 2023-12-22 | 广东盈峰科技有限公司 | Monitor, calibration method and device thereof and storage medium |
| CN117647300A (en) * | 2024-01-30 | 2024-03-05 | 浙江大学 | CVD online in-situ weighing system and method |
| CN117647300B (en) * | 2024-01-30 | 2024-04-23 | 浙江大学 | CVD online in-situ weighing system and method |
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