CN118130374A - System and method for measuring concentration of solution based on refractive index - Google Patents
System and method for measuring concentration of solution based on refractive index Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000006243 chemical reaction Methods 0.000 claims abstract description 40
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 13
- 239000007788 liquid Substances 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 4
- 238000010801 machine learning Methods 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 29
- 238000012512 characterization method Methods 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 85
- 238000006073 displacement reaction Methods 0.000 description 24
- 238000011161 development Methods 0.000 description 8
- 238000009529 body temperature measurement Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
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- 238000004364 calculation method Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
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- 238000012545 processing Methods 0.000 description 1
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- 239000012086 standard solution Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Abstract
The invention relates to the technical field of solution concentration measurement and discloses a system and a method for measuring solution concentration based on refractive index, wherein the system comprises a light beam source, a container for containing a solution to be measured, a photoelectric detector and terminal equipment; the light beam source emits light beams, the incident light rays are emitted into the container according to the optimal incident angle, and emergent light rays are obtained through the container; the optimal incidence angle characterization minimizes the angle between the incident light and the outgoing light; when the photoelectric detector is placed according to a set inclination angle, sensing emergent light rays to obtain target photoelectric conversion data; in addition, the system may further include a temperature sensor for detecting a solution temperature of the solution to be measured, and the terminal device measures a concentration of the solution to be measured based on the target photoelectric conversion data or based on the target photoelectric conversion data and the solution temperature. The invention has the advantages of high resolution, simple structure, high system stability and the like.
Description
Technical Field
The invention relates to the technical field of solution concentration measurement, in particular to a system and a method for measuring solution concentration based on refractive index.
Background
Since an increase in the concentration of the solution generally results in an increase in the refractive index of the solution, which in turn causes a deflection of the outgoing light, the concentration of the solution can be measured by measuring and calibrating the deflection displacement of the outgoing light. The common Abbe refractometer and total reflection refractometer measure the concentration of a solution based on the principle. However, when the change of the refractive index of the solution along with the concentration is not obvious, the deflection displacement of the emergent light is obviously reduced, the measurement resolution is reduced, and then the concentration measurement error is increased. The conventional solution is to increase the propagation distance of the outgoing light, thereby increasing the deflection displacement of the outgoing light. But this tends to increase the volume of the measurement system and reduce the stability of the measurement system.
The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.
Disclosure of Invention
Aiming at the defects of smaller refraction deflection displacement and lower measurement resolution under the condition that the propagation distance of emergent light rays is unchanged in the background art, the invention provides a system and a method for measuring solution concentration based on refractive index.
In a first aspect, the present invention provides a system for measuring a concentration of a solution based on a refractive index, the system comprising a light beam source, a container, a photodetector and a terminal device, the terminal device being connected to the photodetector, the container carrying a solution to be measured;
The light beam source is used for emitting light beams, the light beams are used as incident light rays to be emitted to the container, so that the incident light rays are emitted to the container according to an optimal incident angle I 0 m, and emergent light rays are obtained through the container;
Wherein the optimal incident angle I 0 m is characterized in that an included angle delta between the incident light ray and the emergent light ray is minimized;
The photoelectric detector is used for sensing the emergent light to obtain target photoelectric conversion data when the photoelectric detector is placed according to a set inclination angle theta;
the terminal device is used for acquiring the target photoelectric conversion data and measuring the concentration of the solution to be measured based on the target photoelectric conversion data. The measuring system can realize the concentration measurement of the amplified deflection displacement without increasing the deflection displacement of the emergent light, can obviously improve the resolution of concentration measurement and reduce the measurement error of the concentration of the solution, and has the advantages of high resolution, simple structure, high system stability and the like.
In one example, the system further comprises a temperature sensor for detecting a solution temperature of the solution to be tested; the terminal equipment is provided with a preset regression model, and the preset regression model is obtained through machine learning based on standard alcohol solution concentration and target photoelectric conversion data at different solution temperatures;
And the terminal equipment is used for calling the preset regression model and measuring the concentration of the solution to be measured based on the current solution temperature and target photoelectric conversion data corresponding to the current solution temperature.
The temperature drift is eliminated by the measuring system through monitoring the temperature of the solution and adopting a data fitting mode, so that the problem that the temperature drift is brought during measurement due to the influence of temperature change on the refractive index of the solution can be solved, and the temperature drift measuring system has a wider temperature application range.
In an example, the container is a triangular prism container, wherein the triangular prism container is deflected and lifted according to a set deflection angle by taking a lower vertex angle of the triangular prism container as a deflection axis, so that the incident light rays are incident into the triangular prism container according to an optimal incident angle I 0 m, and the emergent light rays are obtained after being refracted through two non-parallel liquid interfaces of the triangular prism container.
The set deflection angle is related to an upper apex angle of the triangular prism-shaped container, the lower apex angle, and a lowest refractive index of the solution to be measured.
The liquid to be measured of the measuring system is held in the triangular prism-shaped container, the light velocity is refracted through two non-parallel liquid interfaces of the triangular prism-shaped container, and the deviation angle difference delta of the light beam passing through the solutions to be measured with different refractive indexes is larger; furthermore, by tilting the photodetector at a set tilt angle, the deflection displacement of the outgoing light beam is further amplified, which results in a higher measurement resolution of the present invention.
In a second aspect, the present invention provides a method of measuring a concentration of a solution based on a refractive index, the method comprising:
Starting a light beam light source to emit a light beam, so that the light beam is used as an incident light ray to irradiate a container for holding a solution to be measured, wherein the incident light ray is irradiated into the container according to an optimal incident angle I 0 m, an emergent light ray is obtained through the container, and the optimal incident angle I 0 m represents that an included angle delta between the incident light ray and the emergent light ray is minimum;
The photoelectric detector is arranged according to a set inclination angle theta to sense the emergent light so as to obtain target photoelectric conversion data;
Acquiring the target photoelectric conversion data through terminal equipment connected with the photoelectric detector;
and measuring the concentration of the solution to be measured based on the target photoelectric conversion data by the terminal equipment.
The measuring method can realize the concentration measurement of the amplified deflection displacement without increasing the deflection displacement of the emergent light, can obviously improve the resolution of concentration measurement and reduce the measuring error of the concentration of the solution, and has the advantages of high resolution, simple structure, high system stability and the like.
In an example, the method further comprises:
detecting the current solution temperature of the solution to be detected through a temperature sensor, and acquiring the current solution temperature through the terminal equipment;
the measuring, by the terminal device, the concentration of the solution to be measured based on the target photoelectric conversion data includes:
And measuring the concentration of the solution to be measured by the terminal equipment based on the target photoelectric conversion data and the current solution temperature.
In an example, a preset regression model is deployed on the terminal equipment, and the preset regression model is obtained through data fitting based on standard alcohol solution concentration and target photoelectric conversion data at different solution temperatures;
the measuring, by the terminal device, the concentration of the solution to be measured based on the target photoelectric conversion data and the current solution temperature, including:
And calling the preset regression model by the terminal equipment, and inputting the current solution temperature and the target photoelectric conversion data of the current solution temperature as independent variables into the preset regression model so as to measure the concentration of the solution to be measured.
The measuring method of the invention eliminates the temperature drift by monitoring the temperature of the solution and adopting a data fitting mode, thereby solving the problem that the temperature drift is brought during the measurement because the refractive index of the solution is affected by the temperature change, and leading the invention to have wider temperature application range.
In an example, the container is a triangular-cylindrical container, the method further comprising:
Determining an upper vertex angle alpha and a lower vertex angle psi of the triangular prism-shaped container; obtaining the lowest refractive index n 2 of the solution to be detected; obtaining an optimal incident angle I 0 m according to an upper vertex angle alpha, a lower vertex angle phi and the lowest refractive index n 2 of the triangular prism-shaped container;
Determining a set deflection angle of the triangular prism-shaped container according to the optimal incidence angle I 0 m;
the triangular column-shaped container is deflected and lifted according to the set deflection angle by taking the lower vertex angle of the triangular column-shaped container as a deflection shaft;
correspondingly, the starting beam light source emits a light beam, so that the light beam is used as incident light to be emitted to a container containing the solution to be measured, and the starting beam light source comprises:
And starting a light beam source to emit light beams, so that the incident light rays are emitted into the triangular prism-shaped container according to the optimal incident angle I 0 m, and the emergent light rays are obtained after the incident light rays are refracted through two non-parallel liquid interfaces of the triangular prism-shaped container.
Wherein, in one example, the optimal angle of incidence is obtained by the following formula:
Wherein I 0 represents an incident angle of the light beam entering the container, α represents an upper vertex angle of the triangular prism-shaped container, n 2 represents a lowest refractive index of the solution to be measured, n 0 represents an air refractive index, and δ represents an included angle between the incident light and the outgoing light;
And calculating a minimum value point I 0 m of the included angle delta relative to the incident angle I 0, and taking the minimum value point I 0 m as the optimal incident angle.
According to the invention, the optimal incident angle I 0 m is obtained according to the vertex angle alpha of the triangular prism-shaped container and the lowest refractive index n 2, so that the transverse offset of emergent light which is ineffective for measurement is reduced, the width of a measurement system is further reduced, and the width of a light path system is further reduced.
In an example, the set inclination angle θ is determined according to at least a length L of a deflection system, a refractive index variation range of the solution to be measured, and an effective detection length of the photodetector;
wherein the length L of the deflection system characterizes the distance between the beam light source and the photodetector.
According to the measuring method, the photoelectric detector is inclined according to the calculated set inclination angle theta, so that deflection displacement of an emergent light beam is further accurately amplified, and the measuring resolution is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a system for measuring solution concentration based on refractive index according to the present application;
FIG. 2 is a schematic view of a refractive path of a light beam entering a triangular prism container according to an embodiment of the present application;
FIG. 3 is a schematic graph of the angle of incidence as a function of deflection angle provided by an embodiment of the present application;
FIG. 4 is a schematic diagram of an embodiment of the present application for amplifying deflection displacement of an outgoing beam;
FIG. 5 is a schematic diagram of a system for measuring solution concentration based on refractive index according to an embodiment of the present application;
FIG. 6 is a flow chart of a method for measuring solution concentration based on refractive index according to an embodiment of the present application;
fig. 7 is a schematic diagram of a measurement effect of a preset regression model according to an embodiment of the application.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
Furthermore, the terms "first," "second," "third," and the like in the description of the present specification and in the appended claims, are used for distinguishing between descriptions and not necessarily for indicating or implying a relative importance.
Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.
Referring to fig. 1, the system comprises a light beam source 01, a container 02, a photoelectric detector 03 and terminal equipment, wherein the photoelectric detector 03 is in signal connection with the terminal equipment, and the container 02 is loaded with a solution to be measured;
The light beam source 01 is mainly used for emitting light beams, and the light beams are used as incident light rays to be emitted to the container, so that the incident light rays are emitted to the container according to an optimal incident angle I 0 m, and emergent light rays are obtained through the container; wherein the optimal incident angle I 0 m is characterized in that an included angle delta between the incident light ray and the emergent light ray is minimized;
The photodetector 03 is further configured to sense the outgoing light to obtain target photoelectric conversion data when the photodetector 03 is placed according to a set inclination angle θ;
The terminal equipment is mainly used for acquiring the target photoelectric conversion data and measuring the concentration of the solution to be measured based on the target photoelectric conversion data.
In a specific implementation, the light beam emitted by the light beam source 01 is a collimated beamlet light source, such as a semiconductor laser light source; the container 02 preferably uses a triangular cylindrical container, such as a triangular cuvette; the photodetector 03 preferably uses a linear array photodetector such as a linear array Charge-coupled Device (CCD). The terminal device may be a type having a control unit and a display unit, and the terminal device may be manufactured based on an embedded development board (Embedded development board).
For the construction of the system for measuring the concentration of the solution based on the refractive index, the following method is needed to be matched: firstly, the horizontal collimation of the light beam emitted by the light beam source 01 is regulated, and then the set deflection angle of the container 02 is determinedAs shown in fig. 1, the deflection angle/>, is setThe included angle between the bottom edge and the horizontal line is the angle required to deflect the triangular prism-shaped container 02, and finally the set inclination angle theta of the photodetector 03 is determined.
For "determining the set angle of deflection of the container 02The method comprises the following steps:
A1, determining an upper vertex angle alpha and a lower vertex angle psi of the triangular prism-shaped container; obtaining the lowest refractive index n 2 of the solution to be detected; obtaining an optimal incident angle I 0 m according to an upper vertex angle alpha, a lower vertex angle phi and the lowest refractive index n 2 of the triangular prism-shaped container;
the optimal incident angle I 0 m can minimize the deflection angle δ (the angle between the outgoing light and the incoming light), and then reduce the width of the optical path system.
As shown in fig. 2, light is incident on a triangular prism-shaped container containing a solution to be measured, and sequentially passes through the refraction of four refraction interface surfaces, and according to the symbol rule of engineering optics, the refractive angle relationship in the four interfaces can be expressed by the following formula:
n0sinI0＝n1sinI1 (1)
n1sinI1＝n2sinI′1 (2)
α＝I′1-I2 (3)
n2sinI2＝n1sinI′2 (4)
n1sinI′2＝ n0sinI3 (5)
δ＝I0-I3-α (6)
Where n 0 denotes the refractive index of air, n 1 is the refractive index of glass, n 2 is the lowest refractive index of the solution to be measured, α is the upper apex angle of the triangular prism container, ψ is the lower apex angle of the triangular prism container, The angle between the bottom side and the horizontal line is the angle that the triangular prism container needs to deflect, δ is the angle between the outgoing light and the incoming light (this embodiment is called the deflection angle, not shown in fig. 2, see fig. 1), I 0,I1 is the angle of incidence and the angle of refraction of the first air-glass interface, I 1,I′1 is the angle of incidence and the angle of refraction of the first glass-solution interface, I 2,I′2 is the angle of incidence and the angle of refraction of the second solution-glass interface, and I' 2,I3 is the angle of incidence and the angle of refraction of the second glass-air interface, respectively:
the formula (7) is derived from the formulas (1) (2) (3) (4) (5) (6):
In the formula (7), I' 1,I1,I2,I′2 is a calculated intermediate variable used for determining the optimal incident angle I 0, and it is known from the formula (7) that the deflection angle δ is a function of the incident angle I 0, the upper apex angle α of the triangular prism container, the lower apex angle ψ of the triangular prism container, the lowest refractive index n 2 of the solution to be measured and the air refractive index n 0, and that the air refractive index n 0 can be regarded as a constant under general application conditions.
The minimum point I 0 m of the deflection angle δ with respect to I 0 can be found by numerical calculation (as shown in fig. 3);
A2, determining the set deflection angle of the triangular prism-shaped container according to the optimal incidence angle I 0 m And the lower vertex angle of the triangular prism-shaped container is taken as a deflection axis according to a set deflection angle/>Deflection and elevation;
to reduce the lateral offset of the outgoing light beam which is ineffective for measurement, and thus the width of the measurement system, the set deflection angle of the triangular prism-shaped container Should be around I 0 m.
For step "determine the set tilt angle θ of the photodetector 03", the method steps include:
The exit point of the exit ray at the second glass-air interface is approximately at the same point, Δδ is the change in exit ray deflection angle due to the increase in refractive index, as shown in fig. 4, L is the length of the deflection system L, which characterizes the distance between the beam source and the photodetector. y 1 is the deflection displacement of the outgoing light on the photodetector 03 placed vertically, y 2 is the deflection displacement of the outgoing light on the photodetector 03 placed under the condition of being placed according to the inclination angle θ, and y 2 represents the target photoelectric conversion data.
y1＝Ltan(δ+Δδ)-Ltan(δ) (8)
When the photodetector 03 is vertically placed, the deflection displacement y 1 of the outgoing beam on the photodetector 03 is shown in formula (8). Next, the case where the photodetector 03 is placed at the inclination angle θ is deduced:
β＝π-γ-Δδ (11)
Wherein b in the formula (9) is an auxiliary parameter (parameter not belonging to the system) calculated by formula deduction, and is obtained by deduction from formulas (9) (10) (11) (12), when the array photoelectric detector is placed at an inclined angle theta, the deflection displacement y 2 of the emergent beam on the detector is shown as formula (13).
Therefore, without increasing the length L of the deflection system, the photodetectors 03 are arranged at a set inclination angle θ so as to increase the deflection displacement of the outgoing light beam on the photodetectors 03 by a times as much as the original one, see formula (14):
It is understood that y 1 is a reference quantity, and the calculation of equation (8) is to exactly calculate the magnitude of the effective displacement y 2 (i.e. the target photoelectric conversion data) after the photodetector 03 is deflected according to the set tilt angle θ. And demonstrate by calculating 'a' that the invention improves in measurement accuracy over conventional schemes. For example, in the embodiment, taking the setting of the inclination angle θ=60 degrees as an example, after the photodetector 03 deflects 60 degrees, the measurement accuracy of the system is improved by 500%;
Therefore, the appropriate inclination angle of the linear array photoelectric detector is selected as the set inclination angle theta by considering the length L of the deflection system, the refractive index change range of the solution to be detected, the effective detection length of the photoelectric detector and other factors; the refractive index change range of the solution to be measured is determined by the type of the solution to be measured, and belongs to a known quantity; the effective detection length of the photodetector is determined by the hardware properties of the photodetector and is also a known quantity.
The embodiment of the invention has the beneficial effects that: aiming at the technical problem that the measurement resolution is low under a test scene with unchanged propagation distance of emergent light and smaller refraction deflection displacement in the field of solution measurement, the concentration measurement scheme for amplifying the refraction deflection displacement under the condition that the deflection displacement of the emergent light is not increased is provided, and the resolution of concentration measurement can be remarkably improved.
The liquid to be measured in the embodiment is held in a triangular column-shaped container, and is refracted through two non-parallel liquid interfaces, so that the deviation angle difference delta of the collimated beamlets passing through the solutions to be measured with different refractive indexes is larger; furthermore, the deflection displacement of the outgoing light beam is further amplified by tilting the photodetector, which results in a higher measurement resolution of the invention.
Further, the system for measuring the concentration of the solution based on the refractive index according to the embodiment further comprises a temperature sensor for detecting the solution temperature of the solution to be measured;
it is understood that the refractive index of the solution will generally vary significantly with temperature, which will lead to a temperature drift. The temperature sensor is used for monitoring the temperature of the solution to be detected in real time, and the temperature and the displacement of the emergent light beam are used as a variable fitting model, so that the temperature drift effect is further eliminated. The invention has wider temperature application range.
As shown in fig. 5, the temperature sensor of the present embodiment may be a non-contact temperature measurement module, such as an infrared temperature measurement module, which is in signal connection with an embedded development board (terminal device) in a specific implementation.
Specifically, the method for measuring the concentration of a solution based on refractive index of the present invention (in combination with fig. 6) is performed and mainly comprises the steps of:
s10: starting a light beam source to emit a light beam, so that the light beam is used as incident light to irradiate a container containing the solution to be measured;
in a specific implementation, the beam of the beam source is adjusted to the level of collimation of the exiting laser. According to the triangular prism container (using cuvette, right isosceles triangle) with upper and lower vertex angles of 45 deg. and water refractive index of 1.3333 at 20 deg. so that the incident angle I 0m with minimum deflection angle delta is about 30 deg., the right triangle cuvette is deflected by 15 deg. (i.e. set deflection angle) 15 Deg.). The temperature sensor (infrared temperature measuring module) is arranged on the cuvette cover. And mapping the 80% vol ethanol deflected exit beam at the position of the photodetector at about 140mm from the second glass-air interface exit point, i.e., l=140 mm.
S20: the photoelectric detector is arranged according to a set inclination angle theta to sense the emergent light so as to obtain target photoelectric conversion data;
In a specific implementation, a light beam light source (a semiconductor laser) and a terminal device (an embedded development board) are connected to a power supply, a temperature sensor (an infrared temperature measurement module is installed), and a photoelectric detector is connected to the terminal device (the embedded development board), and the photoelectric detector is placed according to a set inclination angle (for example, θ=60°), so that the photoelectric detector senses emergent light to obtain target photoelectric conversion data.
It should be noted that, the execution bodies of steps S10 and S20 in this embodiment are both operators, that is, the operators manually adjust the beam emission of the beam light source and manually adjust the deflection angle of the photodetector. Or in calculating the inclination angle of the photodetector 03 and the deflection angle of the container 02After two angles, corresponding clamps are manufactured, and fine adjustment is performed. For example, in the present embodiment, the set inclination angle θ and the set deflection angle/>, are calculatedAfter these two angles, a support for a triangular cuvette (as container 02) and a line CCD (as photodetector 03) was fabricated using 3D printing techniques according to the calculated set angle, and the optical path was trimmed.
S30: detecting the current solution temperature of the solution to be detected through a temperature sensor, and acquiring the current solution temperature through the terminal equipment; the terminal equipment is further provided with a preset regression model in advance, and the preset regression model is obtained through data fitting based on standard alcohol solution concentration and target photoelectric conversion data at different solution temperatures;
In a specific implementation, experimental calibration data needs to be collected: an AR-120ET alcohol density tester is used for preparing an alcohol solution with standard concentration, the temperature of the standard solution is changed, an infrared temperature measurement module is used for collecting temperature data, and a linear array CCD is used for collecting photoelectric conversion data. The concentration of the standard alcohol solution is changed, and the steps are repeated.
Fitting to the model for data processing: and extracting the spot center point coordinates (namely target photoelectric conversion data) of the emergent light beam projected on the linear array CCD by means of mean value filtering, gaussian fitting and the like. And determining the current solution temperature acquired by the infrared temperature sensor by a mean value solving method. Taking the spot center point coordinate and the current solution temperature as independent variables (characteristics), taking the standard alcohol concentration as a dependent variable (label), and obtaining a preset regression model through machine learning fitting; polynomial fitting regression was used in this example, and the regression model effect is shown in fig. 7.
In the embodiment, the Linux embedded development board is used for developing the terminal equipment, and the preset regression model is deployed on the embedded development board, so that model deployment work can be completed.
S40: and calling the preset regression model by the terminal equipment, and inputting the current solution temperature and target photoelectric conversion data corresponding to the current solution temperature as independent variables into the preset regression model so as to measure the concentration of the solution to be measured.
In the specific implementation, an operator can add alcohol with unknown concentration into the triangular cuvette, and the embedded development board can measure the alcohol concentration by calling a regression model through the acquired temperature and the central point coordinates of the light spots.
The embodiment of the invention provides the concentration measuring method for amplifying deflection displacement without increasing deflection displacement of emergent light, which can obviously improve the resolution of concentration measurement and has the advantages of simple structure, high system stability and wide temperature application range.
In addition, the embodiment of the invention can be used for precise refractive index measurement after being calibrated by using standard refractive index liquid.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (10)
1. A system for measuring solution concentration based on refractive index, which is characterized by comprising a light beam source, a container, a photoelectric detector and terminal equipment, wherein the terminal equipment is in signal connection with the photoelectric detector, and the container is loaded with a solution to be measured;
the light beam source is used for emitting light beams, and the light beams are used as incident light rays to be emitted to the container, so that the incident light rays are emitted to the container according to the optimal incident angle, and emergent light rays are obtained through the container;
Wherein the optimal angle of incidence characterizes a minimum angle of incidence between the incident light and the exiting light;
the photoelectric detector is used for sensing the emergent light to obtain target photoelectric conversion data when the photoelectric detector is placed according to a set inclination angle;
The terminal device is used for acquiring the target photoelectric conversion data and measuring the concentration of the solution to be measured based on the target photoelectric conversion data.
2. The system of claim 1, further comprising a temperature sensor for detecting a solution temperature of the solution to be tested; the terminal equipment is provided with a preset regression model, and the preset regression model is obtained through machine learning based on standard alcohol solution concentration and target photoelectric conversion data at different solution temperatures;
And the terminal equipment is used for calling the preset regression model and measuring the concentration of the solution to be measured based on the current solution temperature and target photoelectric conversion data corresponding to the current solution temperature.
3. The system according to claim 1 or 2, wherein the container is a triangular prism container, wherein the triangular prism container is deflected and lifted according to a set deflection angle by taking a lower vertex angle of the triangular prism container as a deflection axis, so that the incident light rays enter the triangular prism container according to an optimal incidence angle, and the emergent light rays are obtained after being refracted through two non-parallel liquid interfaces of the triangular prism container.
4. The system of claim 1 or 2, wherein the light beam is a collimated beamlet.
5. A method of measuring a concentration of a solution based on a refractive index, the method comprising:
Starting a light beam light source to emit a light beam, so that the light beam is used as an incident light ray to irradiate a container for holding a solution to be measured, wherein the incident light ray is irradiated into the container according to an optimal incident angle, and an emergent light ray is obtained through the container, and the optimal incident angle represents that the included angle between the incident light ray and the emergent light ray is minimum;
The photoelectric detector is arranged according to a set inclination angle to sense the emergent light so as to obtain target photoelectric conversion data;
Acquiring the target photoelectric conversion data through terminal equipment connected with the photoelectric detector;
and measuring the concentration of the solution to be measured based on the target photoelectric conversion data by the terminal equipment.
6. The method of claim 5, wherein the method further comprises:
detecting the current solution temperature of the solution to be detected through a temperature sensor, and acquiring the current solution temperature through the terminal equipment;
the measuring, by the terminal device, the concentration of the solution to be measured based on the target photoelectric conversion data includes:
And measuring the concentration of the solution to be measured by the terminal equipment based on the target photoelectric conversion data and the current solution temperature.
7. The method of claim 6, wherein a preset regression model is deployed on the terminal device, and the preset regression model is obtained by data fitting based on standard alcohol solution concentration and target photoelectric conversion data at different solution temperatures;
the step of measuring, by the terminal device, the concentration of the solution to be measured based on the target photoelectric conversion data and the current solution temperature, further includes:
And calling the preset regression model by the terminal equipment, and inputting the current solution temperature and the target photoelectric conversion data of the current solution temperature as independent variables into the preset regression model so as to measure the concentration of the solution to be measured.
8. The method of claim 6 or 7, wherein the container is a triangular-cylindrical container, the method further comprising:
Determining an upper top angle and a lower top angle of the triangular prism-shaped container; obtaining the lowest refractive index of the solution to be measured; obtaining an optimal incident angle according to the upper vertex angle, the lower vertex angle and the lowest refractive index of the triangular prism-shaped container;
Determining a set deflection angle of the triangular prism container according to the optimal incidence angle;
the triangular column-shaped container is deflected and lifted according to the set deflection angle by taking the lower vertex angle of the triangular column-shaped container as a deflection shaft;
correspondingly, the starting beam light source emits a light beam, so that the light beam is used as incident light to be emitted to a container containing the solution to be measured, and the starting beam light source comprises:
and starting a light beam light source to emit light beams, so that the incident light rays are incident into the triangular prism-shaped container according to the optimal incident angle, and the emergent light rays are obtained after the incident light rays are refracted through two non-parallel liquid interfaces of the triangular prism-shaped container.
9. The method of claim 8, wherein the optimal angle of incidence is obtained by the following equation:
Wherein I 0 represents an incident angle of the light beam entering the container, α represents an upper vertex angle of the triangular prism-shaped container, n 2 represents a lowest refractive index of the solution to be measured, n 0 represents an air refractive index, and δ represents an included angle between the incident light and the outgoing light;
And calculating a minimum value point I 0 m of the included angle delta relative to the incident angle I 0, and taking the minimum value point I 0 m as the optimal incident angle.
10. The method of claim 8, wherein,
The set inclination angle is determined at least according to the length of a deflection system, the refractive index change range of the solution to be detected and the effective detection length of the photoelectric detector;
wherein the length of the deflection system characterizes the distance between the beam light source and the photodetector.
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