CN116295827A - Characterization method of ultraviolet intelligent vision sensor and ultraviolet radiation quantity - Google Patents

Abstract

The present invention relates to the technical field of sensors, in particular to an ultraviolet intelligent visual sensor and a method for characterizing ultraviolet radiation. The ultraviolet intelligent visual sensor comprises a composite solution using _MoO as a solute, water and N-methylpyrrolidone as a solvent, and visual recognition system. When the composite solution of the present invention is irradiated with ultraviolet light, after the MoO ₃ extranuclear electrons in the composite solution receive photon energy, they transition from the ground state to the excited state, and the escaped electrons cause H ₂ O to ionize and become H ⁺ and O ₂ , while MoO ₃ is in the Under the action of hydrogen ions and electrons, it is converted into H _x MoO _3‑x (0<x<1), and the structure of the substance changes, resulting in photochromism of the sample. Because all reactions are between atoms and electrons, the reaction distance is extremely short, and electrons and atoms move at sub-light speed, so the reaction is almost instantaneous and due to the structural characteristics of MoO ₃ and the wave-particle duality of light, a small amount of ultraviolet radiation is also can cause a sample reaction.

Description

A kind of ultraviolet intelligent vision sensor, the characterization method of ultraviolet radiation

technical field

The invention relates to the technical field of sensors, in particular to an ultraviolet intelligent vision sensor and a characterization method for ultraviolet radiation.

Background technique

At present, the demand for ultraviolet detection is divided into two categories, monitoring categories: such as the amount of ultraviolet radiation in a certain area at a certain time period, the monitoring of the integrity of the atmospheric ozone layer, flame monitoring, fire monitoring, corona monitoring, solar ultraviolet effects, etc.; Control category: control of ultraviolet disinfection time, control of ultraviolet curing and polymerization machine irradiation time, control of ultraviolet phototherapy measurement, ultraviolet surface treatment, etc.

At this stage, many devices in ultraviolet monitoring have obvious defects. In the measurement of long-term ultraviolet radiation in the environment, most of the instruments have extremely high requirements on the working environment and cannot work continuously in the natural environment. It is necessary to spend money on the construction of monitoring stations and carry out regular repairs and maintenance. Secondly, its algorithm for calculating the amount of long-term ultraviolet radiation is limited by the principle of instrument measurement, and cannot solve the problem of non-continuity. The current algorithm is the accumulation method, that is, a time period is divided into several moments, and then the sum of the radiation measured at each moment is taken as the total time period radiation. However, time is a continuous variable, and ultraviolet rays are irradiated all the time; therefore, the radiation measured by this method is somewhat different from the real value and cannot be accurately measured. In the instantaneous monitoring of fire, flame, corona, etc., there are also defects in the equipment at this stage. The signs of dangerous events such as fire, flame, and corona are weak before they occur. Once they occur, they develop extremely rapidly and will cause a series of chain disasters. The sensitivity of monitoring equipment and the length of response time are extremely demanding.

However, at this stage, it is basically impossible to directly detect the instantaneous weak ultraviolet rays with equipment at this stage, and to amplify the instantaneous weak ultraviolet rays through other equipment and then detect them cannot meet the requirement of low response time.

Therefore, the prior art still needs to be improved and developed.

Contents of the invention

In view of the above deficiencies in the prior art, the purpose of the present invention is to provide an ultraviolet intelligent visual sensor and a characterization method for ultraviolet radiation, aiming at solving the problem that the existing equipment cannot monitor instantaneous weak ultraviolet rays with low response time.

Technical scheme of the present invention is as follows:

An ultraviolet intelligent visual sensor, comprising: a composite solution using _MoO3 as a solute, water and N-methylpyrrolidone as a solvent, and a visual recognition system;

The composite solution is used to characterize the degree of color depth according to the amount of absorbed ultraviolet radiation; the visual recognition system is used to analyze the degree of color depth to determine the amount of ultraviolet radiation.

Described ultraviolet intelligent vision sensor, wherein, the volume ratio of described water and described N-methylpyrrolidone is (1-2):1.

The ultraviolet intelligent visual sensor, wherein the visual recognition system is implemented based on Python's OpenCV.

A method for characterizing the amount of ultraviolet radiation based on an ultraviolet intelligent vision sensor, comprising steps:

A composite solution is provided, wherein the composite solution uses _MoO as a solute, and water and N-methylpyrrolidone as a solvent;

Using a visual recognition system to construct the functional relationship between the ultraviolet absorption of the composite solution and the discoloration degree of the composite solution;

Using an image device to record the color change of the composite solution to obtain a characterization image;

Using the visual recognition system to process the characterization image to obtain the discoloration degree of the composite solution;

Corresponding the discoloration degree and the functional relationship, the characterization of the ultraviolet radiation amount is realized. The characterization method of the amount of ultraviolet radiation, wherein, the preparation method of the composite solution, comprises the steps:

Adding α- _MoO3 into a mixed solvent of water and N-methylpyrrolidone to obtain a mixed solution;

The mixed solution is placed in an ultrasonic cleaning machine for circulating cooling and ultrasonic treatment to obtain a turbid solution;

The turbid liquid is transferred to a hydrothermal reaction kettle, and a transparent liquid is obtained after the hydrothermal reaction;

The transparent liquid is centrifuged, and the supernatant is stored away from light to obtain the composite solution.

The characterization method of the amount of ultraviolet radiation, wherein the volume ratio of the water to the N-methylpyrrolidone is 1:1.

The method for characterizing the amount of ultraviolet radiation, wherein the temperature of the circulating cooling ultrasonic treatment is 18-22°C.

The method for characterizing the amount of ultraviolet radiation, wherein, the reaction temperature of the hydrothermal reaction is 115-125°C, and the reaction time of the hydrothermal reaction is 2.5-3.5h.

The characterization method of the amount of ultraviolet radiation, wherein, the step of processing the characterization image by using a visual recognition system to obtain the degree of discoloration of the composite solution includes:

After the characterization image is entered into the visual recognition system, the visual recognition system converts the RGB color mode into a hexagonal pyramid model in the color space and performs modeling, and then uses a binarization function to process the color saturation to obtain The degree of discoloration of the complex solution.

Beneficial effects: the present invention provides an ultraviolet intelligent visual sensor and a method for characterizing ultraviolet radiation. The ultraviolet intelligent visual sensor includes a composite solution using _MoO3 as a solute, water and N-methylpyrrolidone as a solvent, and a visual recognition system The composite solution is used to characterize the degree of color depth according to the amount of absorbed ultraviolet radiation; the visual recognition system is used to analyze the degree of color depth to determine the amount of ultraviolet radiation. In the present invention, after the composite solution receives ultraviolet radiation, the change is completed within femtosecond level; when the ultraviolet radiation is applied, the MoO ₃ extranuclear electrons in the composite solution transition from the ground state to the excited state after receiving photon energy, and the escaped electrons cause H ₂ O to generate Ionized to become H ⁺ and O ₂ , while MoO ₃ is transformed into H _x MoO _3-x (0<x<1) under the action of hydrogen ions and electrons, and the material structure changes, resulting in photochromism of the sample. Because all reactions are between atoms and electrons, the reaction distance is extremely short, and electrons and atoms move at sub-light speed, so the reaction is almost instantaneous and due to the structural characteristics of MoO ₃ and the wave-particle duality of light, a small amount of ultraviolet radiation is also can cause a sample reaction. In addition, the ultraviolet intelligent vision sensor adopts diversified construction, combined with the visual recognition system, reduces the response time, simplifies the analysis steps, and improves the measurement accuracy, so that the sensor can be applied to the instantaneous micro-ultraviolet monitoring environment.

Description of drawings

Fig. 1 is a kind of technical roadmap of the characterization method of the ultraviolet radiation amount based on the ultraviolet intelligent vision sensor of the present invention;

Figure 2 is a characterization diagram of the composite solution before and after receiving ultraviolet radiation and after different treatments through the visual recognition system;

Figure 3 is a schematic diagram of visual recognition analysis after long-term ultraviolet radiation in a simulated natural environment;

Fig. 4 is a function diagram of ultraviolet radiation and saturation obtained by the visual recognition system analyzing and simulating the long-term ultraviolet irradiation composite solution in the natural environment.

Detailed ways

The present invention provides an ultraviolet intelligent visual sensor and a characterization method of ultraviolet radiation. In order to make the purpose, technical scheme and effect of the present invention clearer and clearer, the present invention will be further described in detail below. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention belongs. It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have meanings consistent with their meaning in the context of the prior art, and unless specifically defined as herein, are not intended to be idealized or overly Formal meaning to explain.

Ultraviolet rays are produced by the excitation of the outer electrons of atoms. After the British physicist Herschel discovered invisible infrared rays in 1800, the German physicist and chemist John William Ritter insisted on physics "things have The idea of "two-level symmetry" was discovered in 1801 by ultraviolet light.

The earliest UV sensors were based on pure silicon, but according to the National Institute of Standards and Technology, simple silicon diodes also respond to visible light, creating an electrical signal that would otherwise not be needed, resulting in poor accuracy.

More than ten years ago, Japan's Nichia Corporation launched GaN-based crystals, becoming the pioneer of GaN-based crystals, and thus opened up the GaN-based market, which also produced GaN-based ultraviolet sensors, whose accuracy is much higher than The precision of single crystal silicon makes it the most commonly used material for UV sensors.

The core of the GaN-based ultraviolet sensor is gallium nitride (GaN), which is also the third-generation wide-bandgap semiconductor material. Strong response, causing problems with unwanted electrical signals affecting accuracy.

However, at this stage, it is basically impossible to directly detect the instantaneous weak ultraviolet rays with equipment, and the detection of instantaneous weak ultraviolet rays after amplification by other equipment cannot meet the requirement of low response time. Therefore, the market for ultraviolet detection equipment is vast, and there is a lack of core technology for independent research and development.

Based on this, the present invention provides a kind of ultraviolet intelligent visual sensor, comprising: take _MoO3 as solute, water and N-methylpyrrolidone as the composite solution of solvent, and visual identification system; To characterize the depth of color; the visual recognition system is used to analyze the depth of color to determine the amount of ultraviolet radiation.

MoO _x (2<x<3) is a natural and non-toxic n-type semiconductor material. As a traditional transition metal oxide, it has a wide range of applications in energy storage, photocatalysis, color-changing materials, photovoltaic devices, and gas detection. application. The resistance of MoO _x is mainly caused by different bandgap states and ion intercalation, and its bandgap is tunable in the range of 2.8v-3.6v due to the difference of x. This shows that it can be used as a sensor or photovoltaic cell material. The insertion of ions or hydrogen is regarded as an electron attached to the acceptor or donor, so it has various optical and other electrical effects. The application has shown great development potential.

In this embodiment, MoO ₃ , water, and N-methylpyrrolidone are made into a composite solution, which can characterize different phenomena (color depth) according to the amount of absorbed ultraviolet radiation, and then use the visual recognition system to analyze the The ultraviolet radiation amount can be obtained by characterizing the composite solution.

Specifically, when using the ultraviolet intelligent visual sensor to measure the ultraviolet radiation for a long time, it is only necessary to record the initial characterization phenomenon and the end characterization phenomenon of the composite solution, and then use the visual recognition system to analyze the composite solution characterization phenomenon to obtain the ultraviolet ray The amount of radiation; that is, after the composite solution receives ultraviolet radiation, the change is completed within femtoseconds; when the ultraviolet radiation is applied, the electrons outside the nucleus of MoO ₃ in the composite solution transition from the ground state to the excited state after receiving photon energy, and the escaped electrons make H ₂ O Ionization occurs to become H ⁺ and O ₂ , while MoO ₃ is transformed into H _x MoO _3-x (0<x<1) under the action of hydrogen ions and electrons, and the material structure changes, resulting in photochromicity of the sample. Because all reactions are between atoms and electrons, the reaction distance is extremely short, and electrons and atoms move at sub-light speed, so the reaction is almost instantaneous and due to the structural characteristics of MoO ₃ and the wave-particle duality of light, a small amount of ultraviolet radiation is also can cause a sample reaction. Therefore, the ultraviolet intelligent vision sensor of the present invention can be applied to the instantaneous micro-ultraviolet monitoring environment.

Further, the discoloration principle of the composite solution is as follows:

After the ultraviolet photochromic nano system (the composite solution) is irradiated with ultraviolet rays, the _MoO therein becomes an excited state after absorbing ultraviolet rays, and simultaneously generates electrons and holes, the process of which is shown in formula (1):

MoO ₃ +hv→MoO ^* +h ⁺ +e ^- (1)

Then, H ₂ O becomes H ⁺ under the action of holes, and the process is shown in formula (2):

MoO ₃ is converted into H _x MoO _3-x (0<x<1) under the action of hydrogen atoms and electrons, and the process is as follows:

MoO ₃ +xH ⁺ +xe ^- →H _x MoO _3-x

During the whole process, _H2O provided the source of hydrogen ions, while NMP (N-methylpyrrolidone) played the role of a hole-trapping acceptor, which could facilitate the separation of electrons and holes, thus speeding up the reaction process. MoO ₃ is transformed into H _x MoO _3-x (0<x<1), and the structure of the substance changes, making the composite solution photochromic. And the more ultraviolet rays absorbed by the composite solution, the more substances undergoing structural changes, and the deeper the discoloration degree will be.

In some embodiments, the volume ratio of the water to the N-methylpyrrolidone is (1-2):1, at this ratio, sufficient hydrogen ions can be provided for the composite solution, and preferably Use of the role of NMP as a hole-trapping acceptor.

In some implementations, the visual recognition system is implemented based on Python's OpenCV. Specifically, the visual recognition system is written based on Python, using the cross-platform computer vision library OpenCV issued based on BSD license (open source). The recognition principle is that after the visual recognition system enters the characterization image of the composite solution, the RGB color mode is converted into a hexagonal pyramid model in the color space and modeled, and then the binarization function is used to process the color saturation to obtain the result.

Further, the composite solution uses _MoO3 as a solute, water and N-methylpyrrolidone as a solvent, when the composite solution receives ultraviolet radiation and stands still for a period of time, the electrons in the excited state lose energy and return to the ground state, so that The structure of the sample changed again, returning to the color before UV radiation. Therefore, within a certain limit, the composite solution is reusable, easy to obtain materials for production, and harmless to the environment, which is beneficial to the protection and treatment of the environment, and at the same time reduces the cost of use.

In addition, the present invention also provides a method for characterizing the amount of ultraviolet radiation based on the ultraviolet intelligent visual sensor, comprising steps:

Step S10: providing a composite solution, the composite solution uses _MoO3 as a solute, and water and N-methylpyrrolidone as a solvent;

Step S20: using a visual recognition system to construct a functional relationship between the ultraviolet absorption of the composite solution and the discoloration degree of the composite solution;

Step S30: Using imaging equipment to record the color change of the composite solution to obtain a characterization image;

Step S40: using the visual recognition system to process the representative image to obtain the discoloration degree of the composite solution;

Step S50: Corresponding the degree of discoloration with the functional relationship to realize the characterization of the amount of ultraviolet radiation.

In this embodiment, at first, collect data through previous experiments, establish the functional relationship between the degree of discoloration of the composite solution and the amount of ultraviolet absorption, and this process is completed by the visual recognition system; the visual recognition system is written based on Python, and uses a license based on BSD (open source) The cross-platform computer vision library OpenCV released. The recognition principle is that after the visual recognition system enters the sample representation image, the RGB color mode is converted into a hexagonal cone model in the color space and modeled, and then the binarization function is used to process the color saturation to obtain the result. Then according to the established functional relationship and the degree of discoloration of the sample, the amount of ultraviolet radiation is inversely deduced. After inspection and testing, the physical and chemical properties of the composite solution are stable, and the measurement accuracy is not affected by environmental factors. It can work in a relatively harsh natural environment, and the maintenance is simple. There is no need to establish auxiliary facilities such as monitoring stations; moreover, the sensor adopts multiple structures , combined with the visual recognition system, reduces the response time, simplifies the analysis steps, and improves the measurement accuracy at the same time.

Specifically, as shown in Figure 1, the composite solution is irradiated by an ultraviolet light source with a wavelength of 330nm-400nm, the composite solution absorbs ultraviolet rays and a characteristic phenomenon occurs, and then the visual recognition system is used to identify the characteristic phenomenon of the composite solution and analyze the The characterization phenomenon of the composite solution finally obtains the degree of discoloration of the composite solution; and then compares it with the pre-built functional relationship to reversely deduce the amount of ultraviolet radiation.

In some embodiments, the preparation method of the complex solution comprises the steps of:

Step S100: adding α-MoO ₃ into a mixed solvent of water and N-methylpyrrolidone to obtain a mixed solution;

Step S200: placing the mixed solution in an ultrasonic cleaning machine for circulating cooling and ultrasonic treatment to obtain a turbid solution; the turbid solution is milky white;

Step S300: transfer the turbid liquid to a hydrothermal reaction kettle, and obtain a transparent liquid after the hydrothermal reaction; the transparent liquid is light yellow;

Step S400: Centrifuge the transparent liquid, take the supernatant and store it away from light to obtain the composite solution, namely the NMP/water solution of MoO ₃ .

Specifically, in this embodiment, the mixed solvent system of NMP/water is used to provide the driving force for the reaction at a relatively high temperature (about 120°C), and the effective exfoliation of large-sized bulk molybdenum oxide materials is achieved, and the size is several nanometers to Nano-molybdenum oxide materials of tens of nanometers are then excited by ultraviolet light, and hydrogen ions in water are intercalated into the crystal structure of molybdenum oxide, which changes the crystal configuration and transforms the whole into an amorphous structure. At the same time, the molybdenum element in molybdenum oxide The valence state changes from 6+ to 5+, and MoO ₃ becomes MoO _x (2<x<3).

In some embodiments, in the step S100, the volume ratio of the water to the N-methylpyrrolidone is 1:1.

In some embodiments, in the step S200, the temperature of the circulating cooling ultrasonic treatment is 18-22°C.

In a preferred embodiment, the temperature of the circulating cooling ultrasonic treatment is 20°C.

In some embodiments, in the step S300, the reaction temperature of the hydrothermal reaction is 115-125°C, and the reaction time of the hydrothermal reaction is 2.5-3.5h.

In some embodiments, the reaction temperature of the hydrothermal reaction is 120° C., and the reaction time of the hydrothermal reaction is 3 hours.

In some embodiments, in the step S400, the centrifuging the transparent liquid specifically includes: cooling the obtained transparent liquid and transferring it to a centrifuge tube, and centrifuging in a centrifuge at a speed of 12000 rpm.

In some embodiments, in the step S40, the step of using the visual recognition system to process the characteristic image to obtain the discoloration degree of the compound solution includes: after the characteristic image is recorded into the visual recognition system , the visual recognition system converts the RGB color mode into a hexagonal pyramid model in the color space and performs modeling, and then uses a binarization function to process the color saturation to obtain the discoloration degree of the composite solution.

In order to better understand the characterization method of the ultraviolet intelligent visual sensor and ultraviolet radiation amount of the present invention, the following will illustrate:

When the composite solution absorbs ultraviolet rays, due to the different intensity and wavelength of ultraviolet radiation, the doses that trigger the reaction of special substances in the composite solution are also different, and then cause the composite solution to produce different color changes. As shown in Figure 2, it can be seen that the ratio of the composite solution before receiving ultraviolet radiation (A left in Figure 2) to the composite solution after absorbing ultraviolet radiation (A right in Figure 2), and then the samples are captured by a color area array industrial camera The color before and after the change, (A in Figure 2 is the picture captured by the rear camera of the mobile phone), and uploaded to the central processing unit, and the central processing unit applies the visual recognition system (E in Figure 2 is the visual recognition system program module general analysis methods and algorithms). Analyze the different characterizations of the color-changing substances before and after the color-changing of the composite solution. B, C, and D in Figure 2 are the various characterizations after the color-changing substances are peeled off after different processing of the image through the visual recognition system, which is convenient for analysis. The ultraviolet absorption of the composite solution is finally obtained by calculating the function of the change of different characterizations of the color-changing substances in the composite solution and the ultraviolet absorption.

Among them, the working process of the visual recognition analysis system is shown in Figure 3, and Figure 3 is a schematic diagram of the visual recognition analysis after long-term ultraviolet radiation in a simulated natural environment. In this embodiment, the discolored portion of the composite solution is intercepted for analysis, and its saturation value is displayed in real time.

The visual recognition system analyzes and simulates the long-term ultraviolet irradiation compound solution in the natural environment, and obtains the function image of ultraviolet radiation and saturation as shown in Figure 4.

Further, the present invention uses the combination of different characterization phenomena of the composite solution and the visual recognition system to reduce the response time and realize multiple combinations; and the visual recognition system realizes simple, efficient and accurate judgment of the effect of ultraviolet rays on the composite solution. radiation dose.

In summary, the present invention provides a kind of ultraviolet intelligent visual sensor, the characterization method of ultraviolet radiation amount, described ultraviolet intelligent visual sensor comprises _MoO3 as solute, water and N-methylpyrrolidone as the composite solution of solvent, and A visual recognition system; the composite solution is used to characterize the degree of color depth according to the amount of absorbed ultraviolet radiation; the visual recognition system is used to analyze the degree of color depth to determine the amount of ultraviolet radiation. In the present invention, after the composite solution receives ultraviolet radiation, the change is completed within femtosecond level; when the ultraviolet radiation is applied, the MoO ₃ extranuclear electrons in the composite solution transition from the ground state to the excited state after receiving photon energy, and the escaped electrons cause H ₂ O to generate Ionized to become H ⁺ and O ₂ , while MoO ₃ is transformed into H _x MoO _3-x (0<x<1) under the action of hydrogen ions and electrons, and the material structure changes, resulting in photochromism of the sample. Because all reactions are between atoms and electrons, the reaction distance is extremely short, and electrons and atoms move at sub-light speed, so the reaction is almost instantaneous and due to the structural characteristics of MoO ₃ and the wave-particle duality of light, a small amount of ultraviolet radiation is also can cause a sample reaction. In addition, the ultraviolet intelligent vision sensor adopts diversified construction, combined with the visual recognition system, reduces the response time, simplifies the analysis steps, and improves the measurement accuracy, so that the sensor can be applied to the instantaneous micro-ultraviolet monitoring environment.

It should be understood that the application of the present invention is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above descriptions, and all these improvements and changes should belong to the scope of protection of the appended claims of the present invention.

Claims (9)

1. An ultraviolet intelligent vision sensor, characterized by comprising: in MoO ₃ A composite solution which is solute, water and N-methyl pyrrolidone as solvents, and a visual recognition system;

the compound solution is used for representing the degree of color depth according to the ultraviolet radiation absorption; the visual recognition system is used for analyzing the color shade degree to determine the ultraviolet radiation amount.

2. The ultraviolet intelligent vision sensor according to claim 1, wherein the volume ratio of the water to the N-methyl pyrrolidone is (1-2): 1.

3. The ultraviolet intelligent vision sensor of claim 1, wherein the vision recognition system is based on an OpenCV implementation of Python.

4. A method of characterizing the amount of uv radiation based on the uv intelligent vision sensor of any one of claims 1-3, comprising the steps of:

providing a composite solution in MoO ₃ As solute, water and N-methyl pyrrolidone are used as solvent;

constructing a functional relationship between the ultraviolet absorption amount of the composite solution and the color change degree of the composite solution by using a visual recognition system;

recording the color change of the composite solution by using an imaging device to obtain a representation image;

processing the characterization image by using the visual recognition system to obtain the color change degree of the composite solution;

and the color change degree is corresponding to the functional relation, so that the characterization of the ultraviolet radiation quantity is realized.

5. The method for characterizing ultraviolet radiation according to claim 4, wherein the method for preparing the composite solution comprises the steps of:

alpha-MoO ₃ Adding the mixture into a mixed solvent of water and N-methylpyrrolidone to obtain a mixed solution;

placing the mixed solution in an ultrasonic cleaning machine for circulating cooling ultrasonic treatment to obtain turbid liquid;

transferring the turbid liquid into a hydrothermal reaction kettle, and obtaining transparent liquid after hydrothermal reaction;

and centrifuging the transparent liquid, and taking supernatant to store in a dark place to obtain the composite solution.

6. The method of claim 5, wherein the volume ratio of water to N-methylpyrrolidone is 1:1.

7. The method of claim 5, wherein the temperature of the recirculated cooling ultrasonic treatment is 18-22 ℃.

8. The method for characterizing ultraviolet radiation according to claim 5, wherein the reaction temperature of the hydrothermal reaction is 115-125 ℃ and the reaction time of the hydrothermal reaction is 2.5-3.5h.

9. The method of claim 4, wherein the step of processing the characterization image with a visual recognition system to obtain the degree of discoloration of the composite solution comprises:

after the characterization image is input into the visual recognition system, the visual recognition system converts an RGB color mode into a hexagonal pyramid model in a color space and models the hexagonal pyramid model, and then a binarization function is used for processing color saturation to obtain the color change degree of the composite solution.

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