CN102980941A - Method and device for detecting ultrasound gas relative humidity through utilizing sound speed variations - Google Patents
Method and device for detecting ultrasound gas relative humidity through utilizing sound speed variations Download PDFInfo
- Publication number
- CN102980941A CN102980941A CN2012104880641A CN201210488064A CN102980941A CN 102980941 A CN102980941 A CN 102980941A CN 2012104880641 A CN2012104880641 A CN 2012104880641A CN 201210488064 A CN201210488064 A CN 201210488064A CN 102980941 A CN102980941 A CN 102980941A
- Authority
- CN
- China
- Prior art keywords
- humidity
- ultrasonic
- velocity
- module
- cavity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Abstract
The invention discloses a method and a device for detecting the ultrasound gas relative humidity through utilizing sound speed variations. According to the detection method, the relative humidity factor of the current monitoring environment is obtained through measuring the propagation speeds of the sound wave under 100% humidity, 0% humidity and current humidity condition. The detection device comprises a control display module and a measuring cavity, wherein the control display module comprises a DSP (digital signal processor) control module, a display module and a power supply module; the DSP control module is used for generating a fixed-frequency ultrasonic wave signal so as to be transmitted by an ultrasonic transmitter, and controlling the movement of a supersonic receiver so as to carry out operation treatment; a nixie tube display module is mainly used for displaying the result operated by the DSP control module on the display module; and the power supply module is in charge for electric power supply of the whole device. The method and device provided by the invention have the advantages that the measuring environmental requirement is low, the instrument price is low, the measurement is convenient and rapid, the measurement result is exact and reliable, and the like; and the method and the device have important practical application value.
Description
Technical field
The present invention relates to the technical field that ultrasonic propagation velocity is measured, be specifically related to a kind ofly realize detection method and device to gas relative humidity by measuring ultrasonic propagation velocity.
Background technology
What gas humidity reflected is the content of moisture in the gas, is important parameter index in the environmental monitoring.
The departments such as industrial and agricultural production, meteorology, environmental protection, national defence, scientific research, space flight all need often the humidity of environment to be measured and controlled; In daily life, air humidity also has important impact to people's health, and the measurement of humidity can be made measurement to human comfort, thereby improves people's comfort level, improves human living environment.As seen, all become one of commonplace technical requirement to the control of ambient humidity and to the detection of industrial materials moisture content value with analyzing.
But in the environmental parameter of routine, humidity is a parameter of difficult Measurement accuracy.It is more more complex than parameters such as measurement temperature to measure humidity.This be since temperature be one independently measured, and humidity is subject to the impact of the factors such as atmospheric pressure, temperature, and the calibration of humidity also is a difficult problem.
The method of measuring at present humidity has a lot.Manually-operated have hair hygrometer, psychrometer, dew point method etc.Front two kinds of methods generally exist hysteresis and the not high inherent defect of precision; The cost of dew point method is high, and needs the operating personnel of specialty, and responsive to pollutant.01812581.6), " humiture measurement mechanism " (patent No. 200920106276.2) etc. electronic surveying is modal to be to utilize capacitance type humidity sensor to measure, such as " being used for determining the apparatus and method of gas humidity " of utilizing capacitance type humidity sensor to measure (number of patent application:.It is non-linear that the capacitance type sensor shortcoming is that output has, and the impact of stray capacitance often reduces the sensitivity of sensor, causes measuring accuracy to reduce.And present humidity measuring instrument all must handle assembly be positioned over, and certain time can obtain comparatively accurate result in the gas to be measured.
Defective for present existing gas humidity detection method and device, the present invention proposes a kind of brand-new, based on the device of the measurement gas humidity of acoustics, and replace the traditional method of placement measurement mechanism in sample to be tested by extracting the form that sample to be tested detects.Detection method of the present invention is novel, and device construction is simple, and it is convenient to measure, and cost is also lower, and usable range is wide.
Summary of the invention
The object of the invention is to overcome the prior art above shortcomings, a kind of ultrasonic gas relative humidity detection method and device that utilizes sonic velocity change is provided.
A kind of ultrasonic gas relative humidity detection method of utilizing sonic velocity change, it obtains the relative humidity index of current institute monitoring of environmental by measuring the velocity of propagation of sound wave under 100% humidity, 0% humidity and current damp condition:
Wherein, x represents the relative humidity of environment to be measured, c
TBe illustrated in the acoustic velocity that records in the environment to be measured, c
0Acoustic velocity when expression humidity is 0%, c
100Acoustic velocity when expression humidity is 100%.
Further, in the described detection method, the wavelength X when the sinusoidal sound wave of measuring setpoint frequency f by standing wave method is propagated in gas, and then calculate the velocity of propagation of sound wave.
Further, in the described detection method, produce sinusoidal signal by the DSP signal generator, be converted to sound wave and launch to ultrasonic receiver S2 by ultrasonic transmitter S1, ultrasonic receiver S2 converts the ultrasound wave that receives to voltage signal, ultrasonic receiver S2 receive hyperacoustic simultaneously also can the antireflection part ultrasound wave, and the ultrasound wave that sends with ultrasonic transmitter S1 produces localization and interferes, interference theory according to ripple, when distance L between S1 and the S2 is the integral multiple of half-wavelength just, namely
Form standing wave resonance, between any two adjacent resonance state, the displacement of S2 is
By measuring to such an extent that the change of distance Δ L:(between S1 and the S2 can be read by sensor), at last by velocity of sound formula:
c=λ·f （6）
Try to achieve three kinds of velocities of sound in the situation respectively:
1) velocity of sound under 100% humidity
c
100=f·λ
100 （7）
2) velocity of sound under 0% humidity
c
0=f·λ
0 （8）
3) treat the velocity of sound under the measuring moisture
c
T=f·λ
T （9）
And then obtain the humidity of current environment
The present invention also provides the device of realizing above-mentioned detection method, its bag control display module and measurement chamber, and wherein, the control display module comprises DSP control module, display module and power module; Described DSP control module is connected with display module with power module, the DSP control module also with measure the chamber in ultrasonic transmitter be connected with ultrasonic receiver, described DSP control module is launched for ultrasonic transmitter for generation of the fixed frequency ultrasonic signal, the movement of control ultrasonic receiver, the row operation of going forward side by side is processed; The charactron display module mainly is that the result of DSP control module computing is presented on the display module; Power module is responsible for the electric power of whole device and is supplied with.
Further, described device also comprises the USB output module that is connected with the DSP control module, and the USB output module is responsible for the data importing that measures in the equipment such as computing machine.
Further, described measurement chamber comprises cavity, and cavity one end is provided with the piston apparatus A for sample drawn gas, and piston apparatus A medial surface is surveyed and established ultrasonic transmitter B, also is provided with slidably ultrasonic receiver C in the cavity, and the other end of cavity is sealed by lid D.
Further, also be provided with a ultrasonic humidifier E in the described cavity, be used for guaranteeing that humidity reaches 100% in the cavity.
Further, also be included in the ventilated membrane F that is used for guaranteeing inside cavity gas bone dry under 0% damp condition in the described cavity, ventilated membrane F is placed on cavity outlet.
Compared with prior art, the present invention has following advantage and beneficial effect:
It is low that ultrasonic moisture measurement of the present invention has pair measurement environment to require with respect to traditional measuring method, and the instrument low price is measured convenient and swiftly, and the advantage such as measurement result is accurate, reliable has important actual application value.The present invention utilizes under uniform temp, and the relation of gas humidity size and acoustic wave propagation velocity has proposed a kind of ultrasonic measurement air humidity device, and this device is simple and practical, and is easy to detect quick, can be widely used in daily life environment measurement field.Ultrasound wave has the strong characteristic of direction of propagation property, and energy is easy to concentrate, so that instrument detects ultrasonic signal easily; In addition, hyperacoustic frequency is higher than human audibility range, can not affect human normal work and rest when detecting.
Description of drawings
Fig. 1 is under the identical temperature, the funtcional relationship between relative humidity and the gas velocity of sound.
Fig. 2 is the measurement chamber synoptic diagram of hygrometric measurement device wave length of sound.
Fig. 3 is the structural representation of present embodiment ultrasonic gas relative humidity pick-up unit.
Fig. 4 a, Fig. 4 b, Fig. 4 c be 100% humidity in the embodiment, treat to measure under measuring moisture and 0% humidity diagrammatic cross-section in chamber.
Fig. 5 is the performing step process flow diagram of the ultrasonic hygrometric of the present invention.
Fig. 6 is the DSP module process flow diagram in the ultrasonic hygrometric device of the present invention.
Embodiment
Below in conjunction with example enforcement of the present invention is described further, but enforcement of the present invention and protection are not limited to this.
The principle that the present invention utilizes: the speed that sound wave is propagated in the air of different humidity is different, and this difference is apparent in view.In the situation of same temperature, relative air humidity is higher, and the propagation rate of sound wave is lower.
The character of the velocity of sound and sound source is irrelevant, and is only relevant with elasticity, density and the temperature of medium.According to the communication theory of sound wave, the speed that sound wave is propagated in gas is:
In the following formula, K is bulk modulus; ρ is the density of gas.Because the gas that contains the gauge water steam is less than the density of dry gas, and steam-laden gas compares with dry gas, and K is larger, so under uniform temp, in the higher gas of humidity ratio, the velocity of sound is larger.
Simultaneously, a large amount of studies show that, under identical temperature, relative humidity is larger, and the velocity of sound is higher, and linear (such as Fig. 1).
Can show with formula:
In the following formula, x represents the relative humidity of environment to be measured, c
TBe illustrated in the acoustic velocity that records in the environment to be measured, c
0Acoustic velocity when expression humidity is 0%, c
100Acoustic velocity when expression humidity is 100%.
Therefore, draw the relative humidity index that obtains fast current institute monitoring of environmental by measuring the velocity of propagation of sound wave under 100% humidity, 0% humidity and current damp condition
Present embodiment adopts the stationary wave characteristic of sound wave to measure the velocity of propagation of sound wave.According to wave theory, drawn following relation:
c=f·λ （4）
In the following formula (4), c represents the velocity of propagation of sound wave, and f represents the frequency of sound wave, and λ represents the wavelength of sound wave.
Wavelength X when the sound wave that therefore only needs to measure characteristic frequency f is propagated in gas just can calculate the velocity of propagation of sound wave.By standing wave method, can accurately measure the wavelength of sinusoidal sound wave.
Measure the measurement chamber of wavelength as shown in Figure 2.The DSP signal generator produces sinusoidal signal, is converted to sound wave and to ultrasonic receiver S2 emission, ultrasonic receiver can convert the ultrasound wave that receives to voltage signal by ultrasonic transmitter S1.S2 receive hyperacoustic simultaneously also can the antireflection part ultrasound wave, and produce localization with ultrasound wave that S1 sends and interfere.According to the interference theory of ripple, when distance L between S1 and the S2 is the integral multiple of half-wavelength just, namely
Form standing wave resonance.Between any two adjacent resonance state, the displacement of S2 is
Therefore, when the distance L between S1 and the S2 continuously changed, each time cyclical variation of the signal amplitude on the receiver had changed λ/2 with regard to the distance that is equivalent between S1 and the S2.
And the change of distance between S1 and the S2 is easy to record, as reading by sensor.At last by velocity of sound formula:
v=λ·f （6）
Try to achieve three kinds of velocities of sound in the situation respectively:
1) velocity of sound under 100% humidity
c
100=f·λ
100 （7）
2) velocity of sound under 0% humidity
c
0=f·λ
0 （8）
3) treat the velocity of sound under the measuring moisture
c
T=f·λ
T （9）
Formula (7), formula (8) and formula (9) are brought into the humidity that formula (3) had both obtained current environment.
As shown in Figure 3, be the structural representation of present embodiment ultrasonic gas relative humidity pick-up unit, mainly be divided into two parts: control display module section and measurement cavity segment.
Wherein, the control display module has comprised DSP control module, charactron display module and power module.The DSP control module is controlled the movement of ultrasonic reception baffle plate for generation of fixed frequency signal, and the row operation of going forward side by side is processed; The charactron display module mainly is that the result's (namely treating measuring moisture) computing is presented on the charactron; The USB output module is responsible for the data importing that measures in the equipment such as computing machine; Power module then is that the electric power of being responsible for whole device is supplied with.
Fig. 4 a, Fig. 4 b, Fig. 4 c be 100% humidity in the embodiment, treat to measure under measuring moisture and 0% humidity diagrammatic cross-section in chamber.
Three identical parts of cavity are, all be useful on sample drawn gas piston 201, ultrasonic transmitter 202, can before and after the ultrasonic receiver 203 of slip activity and the lid 204 of closed cavity.For the different requirements of the environment that will measure, in the cavity of 100% humidity, be provided with a ultrasonic humidifier 401(such as Fig. 4 b), to guarantee that humidity reaches 100% in the cavity; The cavity outlet of 0% humidity is placed ventilated membrane 402(such as Fig. 4 c of a built-in drying agent), to guarantee inside cavity gas bone dry.
In this example, the DSP module is selected ARM framework chip; Measure cavity material and select stainless steel; Humidifier is selected φ 16mm piezoelectric ceramics oscillating-atomizing sheet; Drying agent is selected Mg (ClO
4)
2(magnesium perchlorate) can dry and reuse; Ultrasonic transmitter and receiver are selected the TCT40-10 model, 10MM/40KHz split ultrasonic sensor (emission T, it is a pair of to receive R), and charactron is selected three 8 sections digital green pipes.
Measuring method and step are carried out according to shown in Figure 5.
Step 1: use piston, first the air in three cavitys is extruded that (the present invention also can adopt a cavity, under different test conditions, adjust and get final product, as the ventilated membrane F that determines whether to use ultrasonic humidifier or be used for guaranteeing inside cavity gas bone dry), then twitching piston extracts gas to be measured and enters in three cavitys close the cover.Simultaneously, gas carries out drying by drying agent in the 0% humidity cavity.
Step 2: 100% humidity cavity is added wet practice.
Step 3: according to the flow process of Fig. 6, ultrasonic transmitter transmission frequency in three cavitys is the ultrasound wave of f, uses standing wave method that the ultrasound wave in three pipelines is carried out acoustic velocity measutement, obtains respectively humidity 100% velocity of sound C
100, humidity 0% velocity of sound c
0, and treat measuring moisture velocity of sound c
T
Step 3: according to the gained velocity of sound, obtain the humidity of environment to be measured according to formula (3), and on charactron the display measurement result.
Above-described embodiment is the better embodiment of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under Spirit Essence of the present invention and the principle, substitutes, combination, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.
Claims (8)
1. ultrasonic gas relative humidity detection method of utilizing sonic velocity change is characterized in that obtaining by measuring the velocity of propagation of sound wave under 100% humidity, 0% humidity and current damp condition the relative humidity index of current institute monitoring of environmental:
Wherein, x represents the relative humidity of environment to be measured, c
TBe illustrated in the acoustic velocity that records in the environment to be measured, c
0Acoustic velocity when expression humidity is 0%, c
100Acoustic velocity when expression humidity is 100%.
2. the ultrasonic gas relative humidity detection method of utilizing sonic velocity change according to claim 1 is characterized in that the wavelength X when propagating in gas by the sinusoidal sound wave that standing wave method is measured setpoint frequency f, and then calculates the velocity of propagation of sound wave.
3. the ultrasonic gas relative humidity detection method of utilizing sonic velocity change according to claim 1, it is characterized in that producing sinusoidal signal by the DSP signal generator, be converted to sound wave and launch to ultrasonic receiver S2 by ultrasonic transmitter S1, ultrasonic receiver S2 converts the ultrasound wave that receives to voltage signal, ultrasonic receiver S2 receive hyperacoustic simultaneously also can the antireflection part ultrasound wave, and the ultrasound wave that sends with ultrasonic transmitter S1 produces localization and interferes, interference theory according to ripple, when distance L between S1 and the S2 is the integral multiple of half-wavelength just, namely
Form standing wave resonance, between any two adjacent resonance state, the displacement of S2 is
By measuring to get the change of distance Δ L between S1 and the S2:, at last by velocity of sound formula:
v=λ·f （6）
Try to achieve three kinds of velocities of sound in the situation respectively:
1) velocity of sound under 100% humidity
c
100=f·λ
100 （7）
2) velocity of sound under 0% humidity
c
0=f·λ
0 （8）
3) treat the velocity of sound under the measuring moisture
c
T=f·λ
T （9）
And then obtain the humidity of current environment
4. realize the device of each described detection method of claim 1～3, it is characterized in that wrapping the control display module and measure the chamber that wherein, the control display module comprises DSP control module, display module and power module; Described DSP control module is connected with display module with power module, the DSP control module also with measure the chamber in ultrasonic transmitter be connected with ultrasonic receiver, described DSP control module is launched for ultrasonic transmitter for generation of the fixed frequency ultrasonic signal, the movement of control ultrasonic receiver, the row operation of going forward side by side is processed; The charactron display module mainly is that the result of DSP control module computing is presented on the display module; Power module is responsible for the electric power of whole device and is supplied with.
5. device according to claim 4 characterized by further comprising the USB output module that is connected with the DSP control module, and the USB output module is responsible for the data importing that measures in the equipment such as computing machine.
6. device according to claim 4, it is characterized in that measuring the chamber and comprise cavity, cavity one end is provided with the piston for sample drawn gas, and the piston medial surface is surveyed and established ultrasonic transmitter, also be provided with slidably ultrasonic receiver in the cavity, the other end of cavity is by sealing of lid.
7. device according to claim 4 is characterized in that also being provided with in the described cavity ultrasonic humidifier E, is used for guaranteeing that humidity reaches 100% in the cavity.
8. device according to claim 4 is characterized in that also being included in the described cavity ventilated membrane F that is used for guaranteeing inside cavity gas bone dry under 0% damp condition, and ventilated membrane F is placed on cavity outlet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210488064.1A CN102980941B (en) | 2012-11-26 | 2012-11-26 | A kind of ultrasonic gas relative humidity detection method and device utilizing sonic velocity change |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210488064.1A CN102980941B (en) | 2012-11-26 | 2012-11-26 | A kind of ultrasonic gas relative humidity detection method and device utilizing sonic velocity change |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102980941A true CN102980941A (en) | 2013-03-20 |
| CN102980941B CN102980941B (en) | 2015-12-02 |
Family
ID=47855159
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210488064.1A Expired - Fee Related CN102980941B (en) | 2012-11-26 | 2012-11-26 | A kind of ultrasonic gas relative humidity detection method and device utilizing sonic velocity change |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102980941B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103336052A (en) * | 2013-06-24 | 2013-10-02 | 华北电力大学 | Indoor relative humidity on-line monitoring system and humidity calculation method |
| CN105829882A (en) * | 2013-10-02 | 2016-08-03 | 雅马哈精密科技株式会社 | Filter element |
| CN107917956A (en) * | 2016-10-05 | 2018-04-17 | 福特环球技术公司 | The system and method determined for humidity and its use |
| CN109870449A (en) * | 2019-02-25 | 2019-06-11 | 京东方科技集团股份有限公司 | A kind of gas monitoring apparatus, system and method and cabinet |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4876889A (en) * | 1988-07-05 | 1989-10-31 | Parthasarathy Shakkottai | Acoustic humidity sensor |
| JPH04204251A (en) * | 1990-11-30 | 1992-07-24 | Nippon Denso Kogyo Kk | Moisture detecting sensor |
| US5387254A (en) * | 1992-03-06 | 1995-02-07 | Matsushita Electric Industrial Co., Ltd. | Humidity measuring device and a heat cooker employing the device |
| JP2000214140A (en) * | 1999-01-20 | 2000-08-04 | Kubota Corp | Sensor |
| US20030188580A1 (en) * | 2002-04-09 | 2003-10-09 | Erik Cardelius | Acoustic gas monitor |
| EP1477798A2 (en) * | 2003-04-28 | 2004-11-17 | Maquet Critical Care AB | Acoustic determination of moisture content of a gas mixture |
| CN102317769A (en) * | 2009-02-19 | 2012-01-11 | 伊莱克斯家用产品股份有限公司 | An apparatus and a method for estimating the air humidity within an oven cavity |
-
2012
- 2012-11-26 CN CN201210488064.1A patent/CN102980941B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4876889A (en) * | 1988-07-05 | 1989-10-31 | Parthasarathy Shakkottai | Acoustic humidity sensor |
| JPH04204251A (en) * | 1990-11-30 | 1992-07-24 | Nippon Denso Kogyo Kk | Moisture detecting sensor |
| US5387254A (en) * | 1992-03-06 | 1995-02-07 | Matsushita Electric Industrial Co., Ltd. | Humidity measuring device and a heat cooker employing the device |
| JP2000214140A (en) * | 1999-01-20 | 2000-08-04 | Kubota Corp | Sensor |
| US20030188580A1 (en) * | 2002-04-09 | 2003-10-09 | Erik Cardelius | Acoustic gas monitor |
| EP1477798A2 (en) * | 2003-04-28 | 2004-11-17 | Maquet Critical Care AB | Acoustic determination of moisture content of a gas mixture |
| CN102317769A (en) * | 2009-02-19 | 2012-01-11 | 伊莱克斯家用产品股份有限公司 | An apparatus and a method for estimating the air humidity within an oven cavity |
Non-Patent Citations (3)
| Title |
|---|
| C. M. HARRIS: "Effects of Humidity on the Velocity of Sound in Air", 《THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA》, vol. 49, no. 3, 31 December 1971 (1971-12-31), pages 890 - 893, XP001331290 * |
| W. VAN SCHALK ET AL.: "High Accuracy Acoustic Relative Humidity Measurement in Duct Flow with Air", 《SENSORS》, vol. 10, 9 August 2010 (2010-08-09), pages 7421 - 7433 * |
| 王华等: "高频有机聚合物SAW湿度传感器的研究", 《压电与声光》, vol. 29, no. 06, 31 December 2007 (2007-12-31), pages 625 - 627 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103336052A (en) * | 2013-06-24 | 2013-10-02 | 华北电力大学 | Indoor relative humidity on-line monitoring system and humidity calculation method |
| CN103336052B (en) * | 2013-06-24 | 2015-12-23 | 华北电力大学 | A kind of indoor relative humidity on-line monitoring system and humidity computing method |
| CN105829882A (en) * | 2013-10-02 | 2016-08-03 | 雅马哈精密科技株式会社 | Filter element |
| CN105829882B (en) * | 2013-10-02 | 2019-06-21 | 雅马哈精密科技株式会社 | The check device and inspection method of sealed package product |
| CN107917956A (en) * | 2016-10-05 | 2018-04-17 | 福特环球技术公司 | The system and method determined for humidity and its use |
| CN109870449A (en) * | 2019-02-25 | 2019-06-11 | 京东方科技集团股份有限公司 | A kind of gas monitoring apparatus, system and method and cabinet |
| CN109870449B (en) * | 2019-02-25 | 2021-11-26 | 京东方科技集团股份有限公司 | Gas monitoring device, system and method and cabinet |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102980941B (en) | 2015-12-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103278561B (en) | Universal ultrasonic liquid concentration detection apparatus | |
| CN108663296B (en) | Dust concentration detection system and detection method based on double-frequency ultrasound | |
| CN104833610B (en) | A kind of liquid character measuring method based on piezoelectric sound wave resonant transducer | |
| CN101819032B (en) | System and method for detecting thickness of industrial boiler scale based on SH (Shear) wave | |
| CN102980941B (en) | A kind of ultrasonic gas relative humidity detection method and device utilizing sonic velocity change | |
| ATE527534T1 (en) | METHOD AND DEVICE FOR MEASURING THE DENSITY OF AN AGRICULTURAL PROPERTY | |
| CN102520019B (en) | Resonant dew point measurement method | |
| CN104764803A (en) | Material stress detection technology based on changes of wavelength of supersonic waves | |
| CN108535158A (en) | A kind of sound-electric compound dust concentration detecting system and detection method | |
| CN105300856A (en) | Method for measuring particle concentration and sizes on basis of ultraphonic impedance spectrum | |
| CN107917768B (en) | Air temperature measuring device and method based on low-frequency sound waves | |
| CN102435287A (en) | Air buoyancy correcting device used in mass measurement of counterbalance | |
| CN110296913B (en) | Detection system and detection method for combustible dust diffusion dynamic concentration | |
| CN106706752A (en) | Method for two frequency point sound measurement of heat capacity of ideal gas | |
| CN102670252B (en) | Intracranial pressure non-invasive measuring method and system | |
| CN204214816U (en) | A kind of device utilizing ultrasound examination vermicular cast iron nodulizing rate | |
| Young | Wireless sensor system for measurement of violin bowing parameters | |
| CN201583657U (en) | Ultrasonic ranging device with temperature and humidity compensation | |
| CN104457967B (en) | Underwater sound sensor sound pressure sensitivity method of testing and device based on inverse piezoelectric effect | |
| CN203164156U (en) | Ultrasonic gas relative humidity detecting device capable of utilizing sound velocity change | |
| Kerdtongmee et al. | Quantifying dry rubber content in latex solution using an ultrasonic pulse | |
| CN110568074B (en) | Wind turbine blade crack positioning method based on non-contact multipoint vibration measurement and Hilbert conversion | |
| CN112051328A (en) | Method for measuring gas acoustic relaxation absorption coefficient | |
| CN203224419U (en) | Liquid density instrument | |
| CN201600312U (en) | Grain bulk density detecting device by utilizing mechanical wave propagation process in grain bulk |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20151202 Termination date: 20211126 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |