Experimental device for measuring moisture absorption capacity of liquid based on laser real-time interference method

Abstract

The utility model discloses an experimental device for measuring moisture absorption capacity of liquid based on a laser real-time interference method, which relates to the technical field of moisture absorption measurement of liquid and comprises a collimation laser source, a first beam splitter prism, a second beam splitter prism, a first plane mirror, a second plane mirror, an absorption cell, an image acquisition camera and a computer, the absorption cell is fixedly arranged between the collimation laser source and the image acquisition camera, and the first beam splitter prism is arranged between the collimation laser source and the absorption cell; the first plane mirror is arranged between the absorption cell and the image acquisition camera, the second beam splitter prism is arranged between the first plane mirror and the image acquisition camera, and the second plane mirror is arranged between the first beam splitter prism and the second beam splitter prism; the first laser and the second laser are converged in the second beam splitter prism and then irradiate into the image acquisition camera, and the computer is in communication connection with the image acquisition camera; according to the utility model, the real-time change condition of the concentration of the experimental solution along with the position and the like in the whole absorption process can be obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of measuring the hygroscopicity of liquid, in particular to an experimental device for measuring the hygroscopicity of liquid based on a laser real-time interference method. Background Art

[0002] As the largest greenhouse gas, water vapor is widely present in the air, which can cause items to become damp and moldy. When the humidity is high, the reproduction and spread of viruses and molds will expand. Even when the humidity is too high, the sweat on the surface of human skin cannot evaporate and can only gather on the skin, causing the body temperature to continue to rise and causing harm to the human body. The ash layer in the air is affected by moisture and will accumulate together to form atmospheric particulate matter, which will cause harm to the body if inhaled. In addition, water has a great impact on the transportation and use of many items, because some substances will cause their physical and chemical properties to change after absorbing moisture, such as ionic liquids. Ionic liquids have the advantages of high stability and low melting point. They are widely used in the development of new energy batteries and the preparation of new materials. The characteristics of ionic liquids are required to be high, but it cannot be ensured that there will be no water in the process of transportation and storage. The entry of water will further affect the viscosity, conductivity and other properties of ionic liquids. Therefore, exploring the hygroscopicity of liquids has great application value.

[0003] At present, the commonly used methods for measuring the amount of greenhouse gases absorbed by liquids are mainly: centrifugation method (Liu Min, Han Heping, Chang Wenhua, etc. Research on the water absorption of silicon dioxide for toothpaste [J]. Oral Care Products Industry, 2022, 32(04): 16-18; Tuo Wenxi, Lin Yingguang, Li Lifeng. Determination of the water absorption of silicon dioxide for toothpaste by centrifugation [J]. Oral Care Products Industry, 2016, 26(05): 34-36), desiccant method, direct weighing method on balance (NAVEA JG, RICHMOND E, Stortini T, et al. Water Adsorption Isotherms on Fly Ash from Several Sources [J]. Langmuir, 2017, 33: 10161-10171.), physical adsorption analyzer (Ma Qingxin. Heterogeneous reaction on the surface of mineral particles and its influence on hygroscopicity [D]. University of Chinese Academy of Sciences, 2010.), infrared spectroscopy technology (IBRAHIM S, ROMANIAS MN, ALLEMAN LY, et al. Water Interaction with Mineral Dust Aerosol: Particle Size and Hygroscopic Properties of Dust [J]. ACS Earth and Space Chemistry, 2018, 2: 376-386.), optical suspension (Cai Chen. Spectroscopic observation of the physical and chemical process of organic-inorganic hybrid single particles suspended by optical tweezers [D]. Beijing Institute of Technology, 2016.) and other methods. However, most of these methods are used to measure the hygroscopicity of solids, or can only obtain the final absorption result of the liquid, and cannot explore the real-time changes of liquid concentration with position during the entire absorption process. The change of liquid concentration has a high reference significance for pharmaceuticals, batteries and crystal growth. Utility Model Content

[0004] The utility model aims to provide an experimental device for measuring the moisture absorption of liquid based on the real-time laser interferometry method, so as to solve the problems existing in the above-mentioned prior art and obtain the real-time changes of the concentration of the experimental solution with the position etc. occurring in the whole absorption process.

[0005] To achieve the above purpose, the utility model provides the following solutions:

[0006] The utility model provides an experimental device for measuring the moisture absorption of liquid based on a laser real-time interference method, comprising: a collimated laser source, a first beam splitter prism, a second beam splitter prism, a first plane mirror, a second plane mirror, an absorption cell, an image acquisition camera and a computer, wherein the collimated laser source can emit collimated laser light, the absorption cell is used to contain an experimental solution, the absorption cell is fixedly arranged between the collimated laser source and the image acquisition camera, the first beam splitter prism is arranged between the collimated laser source and the absorption cell, the first beam splitter prism can disperse the collimated laser light into two laser beams, which are respectively a first laser and a second laser, and the first laser light can be irradiated into the absorption cell to contain the experimental solution. The first plane mirror is placed between the absorption cell and the image acquisition camera, the second beam splitter prism is placed between the first plane mirror and the image acquisition camera, and the second plane mirror is placed between the first beam splitter prism and the second beam splitter prism; the first plane mirror can reflect the first laser from the experimental solution contained in the absorption cell into the second beam splitter prism, and the second plane mirror can reflect the second laser into the second beam splitter prism; the first laser and the second laser are combined at the second beam splitter prism and irradiated into the image acquisition camera, and the computer is communicatively connected to the image acquisition camera.

[0007] Preferably, the collimated laser source comprises a laser and a spatial filter, the laser can emit laser light, and the spatial filter can expand and collimate the laser light emitted by the laser.

[0008] Preferably, the spatial filter comprises a microscope objective, a pinhole filter and a spherical lens, the microscope objective is placed between the laser and the spherical lens, the pinhole filter is placed between the microscope objective and the spherical lens, and the pinhole filter is placed at the focus of the microscope objective.

[0009] Preferably, the microscope objective lens is a 40x microscope objective lens, and the pinhole filter is provided with a small hole with a diameter of 15 μm.

[0010] Preferably, the laser is a semiconductor laser with a wavelength of 589 nm.

[0011] Preferably, the image acquisition camera is a CMOS camera.

[0012] Preferably, the internal dimensions of the absorption cell are 20 mm in length×10 mm in width×45 mm in height.

[0013] Preferably, a blocking cover is further included, and the top end of the absorption tank is open, and the blocking cover can block the top end opening of the absorption tank.

[0014] Compared with the prior art, the utility model has achieved the following technical effects:

[0015] The utility model provides an experimental device for measuring the moisture absorption amount of liquid based on the laser real-time interference method. An absorption pool is arranged to contain an experimental solution. A collimated laser source emits collimated laser. The collimated laser is dispersed into two laser beams, a first laser and a second laser, by a first beam splitter prism. The first laser is irradiated into the experimental solution contained in the absorption pool. The first plane mirror reflects the first laser coming out of the experimental solution contained in the absorption pool to the second beam splitter prism. Finally, the first laser and the second laser are combined by the second beam splitter prism and irradiated into an image acquisition camera. The whole water vapor absorption and diffusion process is observed in real time. A computer can perform image processing and calculation. The change amount of the concentration of the experimental solution is calculated in real time according to the first laser and the second laser images collected by the image acquisition camera. The real-time change of the concentration of the experimental solution with the position etc. in the whole absorption process is obtained. The water vapor absorption amount is calculated, and the time required for the experiment is greatly reduced, so as to realize rapid measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of an experimental device for measuring liquid moisture absorption based on a laser real-time interferometry method provided by the utility model;

[0018] Figure 2 is a schematic diagram of stripe offset;

[0019] Figure 3 Preprocess the original image for hygroscopic streaks;

[0020] Figure 4 Preprocess the grayscale image for hygroscopic streaks;

[0021] Figure 5 It is the median filter image of the preprocessing of hygroscopic stripes;

[0022] Figure 6 Preprocess the binary image for moisture absorption streaks;

[0023] Figure 7 is the image after thinning processing;

[0024] Figure 8 The image after deburring is refined;

[0025] In the figure: 1-laser, 2-microscope objective lens, 3-pinhole filter, 4-spherical lens, 5-first beam splitter prism, 6-absorption cell, 7-first plane mirror, 8-second beam splitter prism, 9-image acquisition camera, 10-computer, 11-second plane mirror. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] The utility model aims to provide an experimental device for measuring the moisture absorption of liquid based on the real-time laser interferometry method, so as to solve the problems existing in the above-mentioned prior art and obtain the real-time changes of the concentration of the experimental solution with the position etc. occurring during the whole absorption process.

[0028] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] like Figure 1 As shown, the utility model provides an experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method, comprising: a collimated laser source, a first beam splitter prism 5, a second beam splitter prism 8, a first plane mirror 7, a second plane mirror 11, an absorption cell 6, an image acquisition camera 9 and a computer 10, the collimated laser source can emit collimated laser, the absorption cell 6 is used to contain the experimental solution, the absorption cell 6 is fixedly arranged between the collimated laser source and the image acquisition camera 9, the first beam splitter prism 5 is arranged between the collimated laser source and the absorption cell 6, the first beam splitter prism 5 can disperse the collimated laser into two laser beams, which are respectively the first laser and the second laser, and the first laser can The first plane mirror 7 is placed between the absorption cell 6 and the image acquisition camera 9, the second beam splitter prism 8 is placed between the first plane mirror 7 and the image acquisition camera 9, and the second plane mirror 11 is placed between the first beam splitter prism 5 and the second beam splitter prism 8; the first plane mirror 7 can reflect the first laser light coming out of the experimental solution contained in the absorption cell 6 into the second beam splitter prism 8, and the second plane mirror 11 can reflect the second laser light into the second beam splitter prism 8; the first laser light and the second laser light are combined in the second beam splitter prism 8 and then irradiated into the image acquisition camera 9, and the computer 10 is connected to the image acquisition camera 9 for communication.

[0030] The utility model provides an experimental device for measuring the moisture absorption of liquid based on the laser real-time interference method. An absorption pool 6 is arranged to contain an experimental solution. A collimated laser source emits collimated laser. The collimated laser is dispersed into two laser beams, a first laser and a second laser, by a first beam splitter prism 5. The first laser is irradiated into the experimental solution contained in the absorption pool 6. A first plane mirror 7 reflects the first laser from the experimental solution contained in the absorption pool 6 to a second beam splitter prism 8. Finally, the first laser and the second laser are combined at the second beam splitter prism 8 and irradiated into an image acquisition camera 9 to observe the entire water vapor absorption and diffusion process in real time. A computer 10 can perform image processing and calculation. The change in the concentration of the experimental solution is calculated in real time according to the first laser and the second laser images collected by the image acquisition camera 9. The real-time change of the concentration of the experimental solution with the position etc. in the entire absorption process is obtained. The water vapor absorption amount is calculated, and the time required for the experiment is greatly reduced to achieve rapid measurement.

[0031] Furthermore, the collimated laser source includes a laser 1 and a spatial filter. The laser 1 can emit laser light, and the spatial filter can expand and collimate the laser light emitted by the laser 1 so as to obtain an ideal collimated light beam.

[0032] Furthermore, the spatial filter comprises a microscope objective lens 2, a pinhole filter 3 and a spherical lens 4. The microscope objective lens 2 is placed between the laser 1 and the spherical lens 4, the pinhole filter 3 is placed between the microscope objective lens 2 and the spherical lens 4, the pinhole filter 3 is placed at the focus of the microscope objective lens 2, and the spatial filter uses a Kepler collimation system to collimate the laser. The microscope objective lens 2 is a 40x microscope objective lens 2, and the pinhole filter 3 is provided with a small hole with a diameter of 15 μm. The assembled spatial filter has the following advantages: first, the microscope objective lens 2 is a 40x microscope objective lens 2, and the pinhole filter 3 is provided with a small hole with a diameter of 15 μm. The objective lens 2 expands the parallel light output by the laser 1 and converts the plane wave into a spherical wave. At the same time, it isolates information such as stray light and prevents the stray light from entering the pinhole filter 3 and the spherical lens 4 to reduce the impact on the irradiation of the experimental solution. The pinhole filter 3 is placed at the focus of the microscope objective lens 2, so that the light passing through the small hole becomes a spherical wave output in the form of a point light source. The spherical lens 4 is then used for collimation to convert the spherical wave converted by the microscope objective lens 2 into a plane wave, thereby obtaining an ideal collimated light.

[0033] As a more preferred implementation of this embodiment, the laser 1 is a semiconductor laser 1 with a wavelength of 589nm. In general experiments, the refractive index of sodium yellow light (589nm) is usually used to indicate the characteristics of the medium, so this embodiment preferably uses a semiconductor laser 1 with a wavelength of 589nm as the light source.

[0034] As a more preferred implementation of this embodiment, the image acquisition camera 9 is a CMOS camera, which is relatively low in price, high in cost performance, and saves use cost. The image size is 3384×2710, and the size of each pixel is 3.69 μm.

[0035] As a more preferred implementation of this embodiment, the internal dimensions of the absorption cell 6 are 20 mm in length×10 mm in width×45 mm in height, which can not only observe the entire diffusion range but also avoid not meeting the boundary conditions during the experiment.

[0036] Furthermore, the experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method provided by the utility model also includes a blocking cover, and the top end of the absorption tank 6 is open, and the blocking cover can block the top end opening of the absorption tank 6.

[0037] The experimental process of the experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry provided by the utility model comprises the following steps:

[0038] Step 1: Prepare the experimental solution;

[0039] Step 2: Inject the same volume of experimental solution into the two same absorption cells 6, seal the top opening of the absorption cell 6 with a sealing cap to isolate the inside of the absorption cell 6 from the outside air, adjust the first beam splitter prism 5 so that the interference fringes are perpendicular to the interface, and when absorption begins, the concentration of the experimental solution also begins to change, and the interference fringes move accordingly, such as Figure 2 As shown, due to the principle of interference fringes, the phase on the same interference fringe is the same. Assume that point A (x0, y0) does not change, and point B (x, y) is any position in the changing area. Only the concentration changes in the x direction and is uniform in the y direction, that is, the concentration of the same layer has the same refractive index, so the phases of points A and B on the same fringe are equal.

[0040] The phase of the interference fringes after the concentration of the experimental solution changes can be written as:

[0041] Formula 1:

[0042]

[0043] Formula 2:

[0044] L(x,y)=∫n(x,y)dz

[0045] L is the optical path difference after the light passes through the diffusion cell;

[0046] From step 2, we can know that:

[0047] Formula 3:

[0048] L(x,y)=L(x)

[0049] Formula 4:

[0050] φ(x,y)=φ(x0,y0)

[0051] Formula 5:

[0052]

[0053] s represents the fringe spacing when the concentration does not change;

[0054] Because point A does not change, Δn(x0,y0)=0, and Formula 5 can be transformed into Formula 6:

[0055]

[0056] n(x) is the refractive index at x, and n0 is the refractive index when it does not change;

[0057] Then, the upper seal is opened at the same time to allow the hygroscopic liquid to be naturally exposed to air with a certain relative humidity, which is recorded as time t=0;

[0058] Step 3: The concentration of the experimental solution changes after it continuously absorbs moisture in the air, causing the refractive index of the experimental solution to change. The image received by the image acquisition camera 9 is no longer a stripe of equal width perpendicular to the interface, but an image with a certain offset, i.e., a moisture absorption image;

[0059] Step 4: Take the laser real-time interference moisture absorption image at time t, such as Figure 2 As shown;

[0060] Step 5: Use MATLAB to preprocess the image obtained in step 4. First, crop the image, select the appropriate position, and then perform grayscale, median filtering and binarization processing, such as Figure 3-Figure 6 As shown;

[0061] Step 6: Thin and remove burrs on the processed image, and compare the obtained ossification image with the original image. Figure 7 As shown, this can get a relatively accurate concentration change area, because this is an important factor affecting the accuracy of the results;

[0062] Step 7: After obtaining the concentration change position, the absorption amount can be obtained using Formula 8; according to the moisture absorption images at different times, the spatial distribution of water in the experimental solution at that time can be intuitively obtained, and the moisture absorption process can be seen;

[0063] In the process of absorption and diffusion, if we know the amount of absorption at a certain position, and then add up the absorption within the range of concentration change, this amount is the total absorption from the beginning to this moment; assuming that we know the concentration at Z, select a height, the absorption at this height can be expressed as:

[0064] Formula 7:

[0065] dm z =M*C(Z)*S*dZ

[0066] M is the molar mass of the substance, S is the corresponding cross-sectional area, and dZ corresponds to the height of a pixel, so its total absorption is expressed as:

[0067] Formula 8:

[0068]

[0069] Z0 represents the position when the image density just changes.

[0070] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An experimental device for measuring the moisture absorption of liquid based on real-time laser interferometry, characterized in that: include: A collimated laser source, a first beam splitter prism, a second beam splitter prism, a first plane mirror, a second plane mirror, an absorption cell, an image acquisition camera, and a computer. The collimated laser source can emit collimated laser light. The absorption cell is used to contain an experimental solution. The absorption cell is fixedly disposed between the collimated laser source and the image acquisition camera. The first beam splitter prism is disposed between the collimated laser source and the absorption cell. The first beam splitter prism can disperse the collimated laser light into two laser beams, namely a first laser and a second laser. The first laser light can be irradiated into the experimental solution contained in the absorption cell. The first plane mirror is placed between the absorption cell and the image acquisition camera, the second beam splitter prism is placed between the first plane mirror and the image acquisition camera, and the second plane mirror is placed between the first beam splitter prism and the second beam splitter prism; the first plane mirror can reflect the first laser light coming out of the experimental solution contained in the absorption cell into the second beam splitter prism, and the second plane mirror can reflect the second laser light into the second beam splitter prism; The first laser and the second laser are combined by the second beam splitter prism and then irradiated into the image acquisition camera. The computer is in communication connection with the image acquisition camera.

2. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 1, characterized in that: The collimated laser source comprises a laser and a spatial filter. The laser can emit laser light, and the spatial filter can expand and collimate the laser light emitted by the laser.

3. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 2, characterized in that: The spatial filter comprises a microscope objective lens, a pinhole filter and a spherical lens, wherein the microscope objective lens is placed between the laser and the spherical lens, the pinhole filter is placed between the microscope objective lens and the spherical lens, and the pinhole filter is placed at the focus of the microscope objective lens.

4. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 3, characterized in that: The microscope objective lens is a 40-fold microscope objective lens, and the pinhole filter is provided with a small hole with a diameter of 15 μm.

5. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 2, characterized in that: The laser is a semiconductor laser with a wavelength of 589 nm.

6. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 1, characterized in that: The image acquisition camera is a CMOS camera.

7. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 1, characterized in that: The internal dimensions of the absorption cell are 20 mm long×10 mm wide×45 mm high.

8. The experimental device for measuring the moisture absorption of liquid based on the laser real-time interferometry method according to claim 1, characterized in that: It also includes a blocking cover, the top end of the absorption tank is open, and the blocking cover can block the top end opening of the absorption tank.

Images