A method of determining the evaporation rate of a droplet

Abstract

The application provides a method for accurately analyzing and measuring the evaporation rate of liquid drops by using a contact angle measuring instrument and image software, which comprises the following steps: firstly, a calculation formula of the volume of an ellipsoid is established by investigating the relationship between the volume of the ellipsoid and the vertical sectional area and the width-height ratio of the ellipsoid; then, the volume pixel value of a single liquid drop with a fixed volume of a series of the liquid to be measured is measured and calculated by using the contact angle measuring instrument and the PHOTOSHOP software, and a regression relationship equation between the volume pixel value and the physical volume value of the single liquid drop is established; further, the volume pixel value of the single liquid drop of the liquid to be measured at different time points within 1 minute is measured, and the physical volume is calculated according to the regression relationship equation between the volume pixel value and the physical volume value; finally, the evaporation rate of the liquid to be measured is calculated by establishing a linear regression equation between the physical volume of the single liquid drop of the liquid to be measured and time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crop disease and pest control, and is a method for detecting the anti-evaporation performance of pesticide liquid and aerial spraying aid diluent, specifically a method for determining the evaporation rate of liquid droplets by using a contact angle measuring instrument and graphic software analysis. BACKGROUND

[0002] Plant protection unmanned aerial vehicle aerial spraying has gradually become one of the main technical measures for crop disease and pest control in China's agricultural production, and the annual prevention and control area has reached more than 1.6 billion mu. Due to the limited payload of plant protection unmanned aerial vehicles, and in order to improve the operation efficiency, the amount of liquid per mu is low, the liquid concentration is high, and the droplet size is fine. In the process of spraying, the evaporation of the liquid can easily lead to the reduction of pesticide utilization rate and unstable prevention and control effect. At the same time, most of the pesticides used by the current plant protection unmanned aerial vehicle aerial spraying are still conventional pesticides suitable for large water volume spraying. In order to further improve the application of conventional pesticides and the effect of plant protection unmanned aerial vehicle aerial spraying, plant protection unmanned aerial vehicle aerial spraying aid products with improved droplet wetting and spreading performance, anti-evaporation and anti-drift performance have been widely developed and applied. Therefore, it is necessary to establish a reliable and operable liquid anti-evaporation performance detection method to evaluate the anti-evaporation performance of the liquid, and then monitor and guide the selection and application of plant protection unmanned aerial vehicle aerial spraying pesticides and aerial spraying aids.

[0003] There are many methods for determining the evaporation rate of liquid, and the main method for determining the evaporation rate of droplets in the process of pesticide spraying is the single droplet evaporation rate determination method using a contact angle measuring instrument and a pendant droplet method. Since the shape of the single droplet suspended during the determination process is an irregular ellipsoid, it is difficult to accurately determine the volume of the droplet, and the droplet volume simulation calculation software provided by the contact angle measuring instrument has limited accuracy in estimating the volume of the droplet. Therefore, it is necessary to establish an accurate single droplet volume determination method to determine the evaporation rate of single droplets, which is used to evaluate the anti-evaporation performance of aerial spraying pesticides and aerial spraying aid diluents, and has great significance in guiding the selection of plant protection unmanned aerial vehicle aerial spraying pesticides and aids, improving the utilization rate of pesticides, and improving the prevention and control effect, and has a wide application prospect. SUMMARY

[0004] In view of the above defects and improvement needs of the prior art, the purpose of the present application is to provide a method for accurately analyzing and determining the evaporation rate of liquid droplets by using a contact angle measuring instrument and image software. First, the calculation formula of the volume of an ellipsoid is established by investigating the relationship between the volume of the ellipsoid and its vertical cross-sectional area and the width-height ratio. Then, the volume pixel value of a single liquid droplet of a series of fixed volumes of the liquid to be measured is determined and calculated by using a contact angle measuring instrument and PHOTOSHOP software, and a regression relationship equation between the volume pixel value and the physical volume value of the single liquid droplet is established. Further, the volume pixel values of the single liquid droplet of the liquid to be measured at different time points within 1 minute are determined, and the physical volume is calculated according to the regression equation between the volume pixel value and the physical volume value. Finally, the evaporation rate of the liquid to be measured is calculated by establishing a linear regression equation between the physical volume of the single liquid droplet of the liquid to be measured and time.

[0005] According to the purpose of the present application, the present application provides a method for determining the evaporation rate of liquid droplets, comprising the following steps:

[0006] S1. Based on the method for calculating the volume pixel value of liquid in a single droplet, the volume pixel value of a series of liquid droplets with known physical volume values is determined, and a standard curve is drawn with the measured physical volume value as the ordinate and the corresponding volume pixel value as the abscissa, and a regression relationship equation between the physical volume value and the volume pixel value of the liquid to be measured in a single droplet of the liquid to be measured is established;

[0007] S2. A predetermined volume of the liquid to be measured is taken with a microsyringe, the microsyringe is fixed in the syringe fixing groove of the contact angle measuring instrument, and the needle tube of the microsyringe is stretched into the micro temperature and humidity control oven, the temperature and relative humidity in the control oven are recorded, the industrial camera photographing function of the contact angle measuring instrument is started, the photograph of the syringe needle tube is taken and saved, then the liquid droplet is hung by pressing the microsyringe plunger, the industrial camera photographing function of the contact angle measuring instrument is immediately started, and the droplet morphology is recorded by taking photographs at a plurality of time points (T1, T2, T3, T4, T5, T6, T 7， , preferably 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds) after the formation of the liquid droplet;

[0008] S3. Based on the histogram function of the image processing software, the length pixel value L T0 , the width pixel value W T0 of the needle tube in the photograph of the needle tube, and the height pixel value H Ti , the width pixel value D Ti , the area pixel value S Ti , and the length pixel value L Ti of the liquid droplet in the photograph of the liquid droplet are determined;

[0009] S4. According to the method for determining and calculating the volume pixel value of the liquid to be measured in the liquid droplet, the calculation formula V Ti =(4 / 3)×π -1 / 2 ×STi 3 / 2 ×(D Ti / H Ti ) 1 / 2 -π×(W0 / 2) 2 ×(L T0 -L Ti ), measuring and calculating the pixel value of the volume of the test liquid in the droplet at the corresponding time point, and calculating the physical volume of the test liquid in the droplet at the corresponding time point according to the regression relationship equation between the physical volume of the test liquid in the droplet and the pixel volume established in S1;

[0010] S5. Using the physical volume of the test liquid in the droplet at different time points measured in S4, establish a linear regression equation between the physical volume of the test liquid in a single droplet and time, with the physical volume as the ordinate and the corresponding time point as the abscissa. The slope of the line is the evaporation rate of the test liquid.

[0011] Furthermore, the preparation method of a single liquid droplet is as follows: use a 10-μl flat-tip microsyringe to accurately draw a certain volume of the liquid to be tested, place the microsyringe in the syringe fixing groove of the contact angle meter, press the microsyringe core rod, and completely squeeze out the liquid to be tested in the syringe to form a hanging single droplet at the lower end of the syringe needle.

[0012] Furthermore, the method for calculating the volume of an ellipsoid based on its longitudinal cross-sectional area and aspect ratio in step S1 includes: by examining the relationship between the ellipsoid volume (V) and the ellipsoid aspect ratio (D / H) under the condition that the ellipsoid's longitudinal cross-sectional area (S) is constant, establishing a regression equation between the two: V=C×(D / H) 1 / 2 Then, we examine the relationship between the constant C and the vertical cross-sectional area of ​​the ellipsoid (S) and the volume formula of the ellipsoid, and establish the regression relationship equation between the two: C=(4 / 3)×π -1 / 2 ×S 3 / 2 The calculation formula of the ellipsoid volume based on the vertical cross-sectional area and the aspect ratio of the ellipsoid is V=(4 / 3)×π -1 / 2 ×S 3 / 2 × (D / H) 1 / 2 .

[0013] Furthermore, the method for measuring and calculating the liquid volume pixel value in step S4 includes: using a contact angle meter and image processing software to measure the area pixel value, width pixel value, height pixel value, needle tube width pixel value and needle tube length pixel value of the droplet, and calculating the volume of the ellipsoid using the formula V=(4 / 3)×π -1 / 2 ×S 3 / 2 × (D / H) 1 / 2The volume pixel value of a single droplet is calculated, and then the cylinder volume formula is used to calculate the needle tube pixel volume in the droplet. The difference between the two is the liquid volume pixel value in the droplet.

[0014] Furthermore, the contact angle meter is equipped with a control system, a sample injection system, a camera system, a stage, and a light source system. The industrial camera is an industrial camera equipped with the contact angle meter; the micro temperature and humidity control box is composed of a heating wire, a temperature control system, a humidifying device, and a temperature and humidity meter.

[0015] In addition, the method is used to measure the evaporation rate of droplets of pesticide solution or aerial spraying adjuvant dilution and evaluate the anti-evaporation performance of the pesticide solution or aerial spraying adjuvant dilution.

[0016] Compared with the existing technology, the present invention can achieve more accurate and efficient measurement, and the beneficial effects of the present invention are as follows:

[0017] (1) When using the hanging drop method to measure the evaporation rate of a droplet, the droplet's morphology does not change significantly after evaporation in a short period of time. The main parameters of the droplet morphology, such as the height and width of the droplet, change little. The traditional ellipsoid volume calculation formula cannot sensitively reflect the volume change of the droplet. To address the above problem, the present invention examines the relationship between the ellipsoid volume, its longitudinal cross-sectional area, and its aspect ratio, and establishes a formula for calculating the ellipsoid volume based on the longitudinal cross-sectional area and the aspect ratio of the ellipsoid: V = (4 / 3) × π -1 / 2 ×S 3 / 2 × (D / H) 1 / 2 , which can react to the change of droplet volume more sensitively and with high accuracy.

[0018] (2) When measuring droplet evaporation rate using the hanging drop method, the droplet morphology is not a standard ellipsoid. Since the width and height of the droplet morphology do not change significantly during the measurement, the calculation of the ellipsoidal longitudinal cross-sectional area using these indicators cannot accurately reflect the change in droplet morphology. To address this issue, the present invention utilizes the histogram function of Photoshop software to directly calculate the longitudinal cross-sectional area of ​​the droplet, which can more directly and accurately reflect the change in droplet morphology, and thus reflect the change in droplet volume.

[0019] (3) When using the hanging drop method to measure the droplet evaporation rate, the syringe needle is usually treated with an extremely low surface energy material during the measurement process to reduce the occurrence of the droplet containing the needle. However, due to the close contact between the droplet and the needle, a certain length of the needle is always contained in the droplet. The present invention specifically proposes a method for calculating the volume of the test liquid in the droplet as the difference between the volume of the droplet and the volume of the needle contained in the droplet. This method can more accurately calculate the actual volume of the liquid during the droplet evaporation rate process, while avoiding the traditional operation of treating the syringe needle with a low surface energy material, thereby preventing the influence of the low surface energy material on the evaporation of the test liquid droplet.

[0020] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or can be learned by practice of the application. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the purpose and technical solutions of the present application, the present application will be further introduced and described below in combination with the drawings of the embodiments of the present application. Obviously, the following described embodiments are only some of the embodiments of the present application, not all the embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative labor should belong to the protection scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in any way without conflict.

[0022] The method for measuring the evaporation rate of a droplet provided by the embodiments of the present application includes a method for preparing a liquid single droplet, a method for calculating the volume of an ellipsoid based on the longitudinal cross-sectional area and the width-height ratio of the ellipsoid, a method for calculating the liquid volume pixels in a single droplet based on image processing software, and a method and steps for measuring the evaporation rate of a droplet.

[0023] First, a method for calculating the volume of an ellipsoid based on the longitudinal cross-sectional area and the width-height ratio of the ellipsoid is established.

[0024] Based on the morphological structure characteristics of a droplet, the cross-sectional shape is a circle, given the ellipsoid morphological index values a, b, c (a, b, c are the half-axis lengths of the ellipsoid along the x, y, and z axes, and a=b among them), the relationship between the ellipsoid volume (V) and the ellipsoid width-height ratio (D / H) is investigated under the condition that the vertical cross-sectional area (S) of the ellipsoid is constant, and a regression relationship equation V=C×(D / H) between the two is established. 1 / 2 (the square value of the correlation coefficient of the regression equation R 2 =1, R 2 represents the reliability of the equation, and the closer to 1 indicates that the correlation is high), where C is a constant related to the vertical cross-sectional area of the ellipsoid.

[0025] The relationship between the constant C in the regression relationship equation of the ellipsoid volume (V) and the ellipsoid width-height ratio (D / H) and the vertical cross-sectional area (S) of the ellipsoid is investigated, and a regression relationship equation C=(4 / 3)×π -1 / 2 ×S 3 / 2 (R 2 =1) between the two is established in combination with the ellipsoid volume calculation formula V=4 / 3×π×a×b×c.

[0026] The calculation formula of the ellipsoid volume (V) based on the vertical cross-sectional area (S) of the ellipsoid and the width-height ratio (D / H) of the ellipsoid is obtained by combining the above regression relationship equations: V=(4 / 3)×π -1 / 2 ×S 3 / 2× (D / H) 1 / 2 .

[0027] Secondly, the pixel value calculation formula of the volume of the liquid to be measured in the single droplet of the liquid to be measured is established:

[0028] A micropipette with a predetermined volume (for example, 10 microliters) is selected, and a certain volume of the liquid to be measured is accurately sucked, the micropipette is placed in the fixed groove of the contact angle measuring instrument, the industrial camera photographing function of the contact angle measuring instrument is turned on, a picture N of the micropipette is taken and saved, the micropipette rod is pressed, the liquid to be measured in the micropipette is completely squeezed out, a hanging droplet is formed at the lower end of the micropipette, the industrial camera photographing function of the contact angle measuring instrument is immediately turned on, a picture C of the droplet shape is taken and saved.

[0029] The pixel value L of the length of the micropipette in the picture N of the micropipette, the pixel value W of the width of the micropipette, the pixel value L of the length of the micropipette in the picture C of the droplet shape, the pixel value H of the height of the droplet, the pixel value D of the width of the droplet, and the pixel value S of the area of the droplet are respectively measured and recorded by using an image processing software (for example, PHOTOSHOP software) and based on the histogram function of the software. N N C C C C .

[0030] Since the droplet hanging at the lower end of the micropipette is in close contact with the micropipette, the droplet contains part of the micropipette, the pixel value (L) of the length of the micropipette contained in the droplet is the difference between the pixel value (L N ) of the length of the micropipette in the picture N of the micropipette and the pixel value (L C ) of the length of the micropipette in the picture C of the droplet shape, that is, L = L N -L C . Meanwhile, according to the volume calculation formula V = π × r 2 × h (r is the radius of the bottom of the cylinder, and h is the length of the cylinder), the pixel value (V1) of the volume of the micropipette contained in the droplet is V1 = π × (W N / 2) 2 × (L N -L C ), W N / 2 is the radius r of the cylinder, and L Ni -L Ci is the height h of the cylinder.

[0031] According to the volume calculation formula V = (4 / 3) × π -1 / 2 × S 3 / 2 × (D / H) 1 / 2 of the ellipsoid established in the application, V2 = 0.7524 × S C ​​​​​3 / 2 ×(D C / H C ) 1 / 2 The pixel value of the volume of the single droplet suspended at the lower end of the lower part of the needle tube of the microinjector is calculated; the pixel value of the volume of the droplet is calculated according to the formula V Ci = V2-V1, that is, the difference between the pixel value (V2) of the volume of the single droplet suspended at the lower end of the lower part of the needle tube of the microinjector and the pixel value (V1) of the volume of the droplet. The calculation formula of V1 and V2 is substituted into the formula V Ci = V2-V1, to establish the calculation formula of the volume of the droplet: V C =(4 / 3)×π -1 / 2 ×S C 3 / 2 ×(D C / H C ) 1 / 2 -π×(W N / 2) 2 ×(L N -L C )。

[0032] The present application also verifies the volume calculation formula of the ellipsoid based on the longitudinal cross-sectional area and the width-height ratio as follows: based on the morphological characteristics of the droplet, 20 sets of width (D i ) and height (H i ) index values of the ellipsoid with a circular cross section are randomly given, the longitudinal cross-sectional area (S i ) of the ellipsoid is calculated according to the formula S i =π×(D i / 2)×(H i / 2), and the volume of the ellipsoid is calculated according to the formula V1=(4 / 3)×π×(D i / 2) 2 ×(H i / 2) and the formula V2=(4 / 3)×π -1 / 2 ×S i 3 / 2 ×(D i / H i ) 1 / 2 respectively, and the results are shown in Table 1. As can be seen from Table 1, V I =V2, indicating that the ellipsoid volume calculation formula established by the present application can accurately calculate the volume of the ellipsoid.

[0033] Table 1 Comparison of the volumes of the ellipsoids calculated by two kinds of ellipsoid volume calculation methods

[0034] ;

[0035] Meanwhile, the present application also verifies the accuracy of the estimation of the volume of the droplet by using the ellipsoid volume calculation formula based on the longitudinal cross-sectional area and the width-height ratio as follows:

[0036] Prepare 19 kinds of different component emulsions, respectively using the single droplet volume pixel value determination method provided by the present application and the traditional ellipsoid volume calculation formula V=(4 / 3)×π×(D i / 2) 2 ×H i Determine the single droplet volume pixel value (V1) and (V2) of 19 kinds of different component emulsions and water with a volume of 3.0 microliters. The morphological index values of the droplets, longitudinal section area (S i ), droplet width (D i ), droplet height (H i ), microsyringe initial needle length (L N ), droplet outer needle length (L i ), needle width (W N ) index values, the droplet volume pixel value (V1) determined by the method provided by the present application, and the droplet volume pixel value (V2) calculated by the traditional ellipsoid volume calculation formula, see Table 2.

[0037] Table 2 Morphological index values and volume pixel values of single droplets of different component emulsions and water

[0038] ;

[0039] The basic parameter estimation module of the DPS analysis software is used to estimate the basic parameters of the droplet volume pixel values V1 and V2 calculated by the two calculation methods, and the results are shown in Table 3. As can be seen from Table 3, the range, standard deviation, standard error and coefficient of variation of the volume pixel values of the 20 single droplets determined by the determination and calculation method provided by the present application are 337361.57, 102299.39, 22874.84 and 0.0048, respectively, while the range, standard deviation, standard error and coefficient of variation of the volume pixel values of the 20 single droplets calculated by the traditional volume calculation formula are 680189.35, 198353.09, 44353.10 and 0.0094, respectively. It can be seen that the determination of the droplet volume pixel value by the single droplet volume pixel value determination method provided by the present application is more accurate, and the accuracy of the method for calculating the ellipsoid volume pixel value by the traditional ellipsoid volume calculation formula is improved by about 1 times.

[0040] Table 3 Basic parameter estimation table of single droplet volume pixel values of 19 kinds of different component emulsions and pure water

[0041] ;

[0042] In combination with the verification results, further, the method for determining the droplet evaporation rate provided by the present application comprises the following steps.

[0043] S1. Establishing a regression relationship equation between the physical value of the volume of the test liquid in the single droplet of the test liquid and the volume pixel value of the test liquid

[0044] According to the method for measuring and calculating the volume pixel value of the test liquid in the single droplet of the test liquid provided by the present application, the volume pixel value of the test liquid in the single droplet of the test liquid is measured and calculated according to the formula V Ci =(4 / 3)×π -1 / 2 ×S Ci 3 / 2 ×(D Ci / H Ci ) 1 / 2 -π×(W Ni / 2) 2 ×(L Ni -L Ci ), wherein i=1, 2, 3, 4, 5, respectively corresponding to treatment 1, treatment 2, treatment 3, treatment 4 and treatment 5. The standard curve is drawn with the measured physical value of the volume as the ordinate and the volume pixel value of the test liquid in the single droplet of the test liquid as the abscissa, and a regression relationship equation between the physical value of the volume of the test liquid in the single droplet of the test liquid and the volume pixel value of the test liquid is established.

[0045] S2. Photographing and saving the morphologies of the microsyringe needle tube and the single droplet of the test liquid at different time points

[0046] A predetermined volume (for example, 3 microliters) of the test liquid is accurately sucked by the microsyringe, the microsyringe is fixed in the syringe fixing groove of the contact angle measuring instrument, and the microsyringe needle tube is stretched into the micro temperature and humidity control oven, the temperature and relative humidity in the control oven are recorded, the industrial camera photographing function of the contact angle measuring instrument is turned on, and the syringe needle tube photo T0 is photographed and saved; the microsyringe plunger is pressed to completely squeeze out the test liquid in the syringe, so that a hanging droplet with a volume of 3.0 microliters is formed at the lower end of the syringe needle tube, the industrial camera photographing function of the contact angle measuring instrument is immediately turned on, the droplet morphology is photographed and recorded at 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds and 60 seconds after the droplet is formed, and saved as photos T1, T2, T3, T4, T5, T6 and T7.

[0047] S3. Measuring the pixel values of the vertical cross-sectional area, height, width of the single droplet, and the length and width of the needle tube

[0048] The image processing software is used to measure the pixel values of the height H Ti , the width D Ti and the area S of the droplet in the photos T1, T2, T3, T4, T5, T6 and T7, respectively, based on the histogram function of the image processing softwareTi , the length pixel value L of the microinjector needle tube outside the droplet Ti , the length pixel value L of the microinjector needle tube outside the droplet in the photograph T0 is measured simultaneously T0 and the width pixel value W T0 , the subscript T i corresponds to the photographs T1, T2, T3, T4, T5, T6, and T7, respectively.

[0049] S4. Calculate the volume pixel value and the volume physical value of the test liquid in the single droplet of the test liquid at different time points.

[0050] According to the method for measuring and calculating the volume pixel value of the test liquid in the single droplet of the test liquid provided by the present application, the volume pixel value V Ti of the test liquid in the single droplet of the test liquid is calculated according to the formula V -1 / 2 = (4 / 3) × π Ti × S 3 / 2 × (D Ti / H Ti ) 1 / 2 - π × (W T0 / 2) 2 × (L T0 -L Ti ) (which can be approximated as V Ti = 0.7524 × S Ti 3 / 2 × (D Ti / H Ti ) 1 / 2 - π × (W T0 / 2) 2 × (L T0 -L Ti )), wherein i = 1, 2, 3, 4, 5, 6, and 7, respectively, correspond to the droplet shape photographs T1, T2, T3, T4, T5, T6, and T7. According to the regression relationship equation between the physical volume and the pixel volume of the test liquid in the droplet established in S1, the physical volume of the test liquid in the single droplet of the test liquid at 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and 60 seconds is calculated.

[0051] S5. Calculate the evaporation rate of the test liquid.

[0052] Using the physical volume of the test liquid in the single droplet of the test liquid at 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and 60 seconds measured in S4, the physical volume is taken as the ordinate, and the corresponding time is taken as the abscissa, a linear regression equation of the physical volume of the test liquid in the single droplet of the test liquid and time is established, and the slope of the straight line is the evaporation rate of the test liquid.

[0053] Preferably, the method for determining and calculating the volume pixel value of the liquid to be detected in the single droplet of the liquid to be detected provided by the present application is determined and calculated according to the formula V Ci =(4 / 3) x π -1 / 2 x S Ci 3 / 2 x (D Ci / H Ci ) 1 / 2 - π x (W Ni / 2) 2 x (L Ni -L Ci ), the volume pixel value (V Ci ) of water in the photos of the water droplets of 2.4 microliters (treatment 1), 2.6 microliters (treatment 2), 2.8 microliters (treatment 3), 3.0 microliters (treatment 4), and 3.2 microliters (treatment 5) is determined and calculated. The morphological index values of the droplets are the longitudinal cross-sectional area (S Ci ), the droplet width (D Ci ), the droplet height (H Ci ), the initial needle length (L Ni ) of the microsyringe, the outer needle length (L Ci ) of the droplet, the needle width (W Ni ), and the volume pixel value (V Ci ) of water in the water droplets are shown in Table 4 (the pixel value of each 1 millimeter length in the photo is 106.67). The standard curve is drawn with the volume physical value of the water droplets as the vertical coordinate and the corresponding volume pixel value of water in the water droplets as the horizontal coordinate, and the regression relationship equation between the volume physical value and the volume pixel value of water in the water droplets is y = 0.1006x / 100000 + 0.41776, R 2 = 0.9983.

[0054] Table 4 Morphological index values and volume pixel values of water droplets of different volumes

[0055] ;

[0056] According to the method for determining the evaporation rate of the droplet provided by the present application, a 3-microliter water droplet is prepared in a temperature-controlled box at a temperature of 34°C and a relative humidity of 36.5% using a microsyringe equipped with a contact angle measuring instrument, and the morphological photos T1, T2, T3, T4, T5, T6, and T7 at 0 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, and 60 seconds after the formation of the droplet, and the original photo T0 of the needle of the microsyringe before the formation of the droplet are taken. The pixel value H Ti of the droplet height, the pixel value D Ti of the droplet width, and the pixel value STi , the length pixel value L of the microsyringe needle outside the droplet Ti , and at the same time measure the length pixel value L of the microinjection needle outside the droplet in photo T0 T0 and width pixel value W T0 , and calculate the volume pixel value of water in the droplets of photos T1, T2, T3, T4, T5, T6, and T7 (V Ti ), and then calculate the physical volume of water in the corresponding water droplet (V according to the regression relationship equation between the volume physical value of water and the volume pixel value: y = 0.1006x / 100000 + 0.41776 i The measured and calculated data are shown in Table 5. Using the calculated physical volume of water in the droplet as the ordinate and the corresponding time as the abscissa, a linear regression equation y = -0.0048x + 2.8993 (R² = 0.9881) was established for the physical value of the water volume in the droplet versus time. The slope of the line is the evaporation rate of the test liquid, 0.0048 μL / s, which translates to an evaporation volume of 0.288 μL per minute.

[0057] Table 5 Water drop evaporation rate measurement data

[0058] ;

[0059] The present invention also provides various types of programmable processors (FPGA, ASIC or other integrated circuits), which are used to run programs, wherein the steps in the above embodiments are executed when the programs are run.

[0060] The present invention also provides a corresponding computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the memory implements the steps in the above-mentioned embodiment when executing the program.

[0061] Although the embodiments disclosed in the present invention are as described above, the contents described are merely embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art in the field to which the present invention belongs may make any modifications and changes, equivalent substitutions, etc. in the form and details of implementation without departing from the spirit and principles disclosed in the present invention, and these shall fall within the scope of protection of the present invention. Therefore, the scope of patent protection of the present invention shall still be subject to the scope defined by the attached claims.

Claims

1. A method of determining the evaporation rate of a droplet, characterized by, The method comprises the following steps: S1. Determining the volume pixel value of a series of droplets with known volume physical values based on a single-droplet liquid volume pixel value calculation method, and drawing a standard curve with the measured volume physical value as the ordinate and the corresponding volume pixel value as the abscissa to establish a regression relationship equation between the volume physical value and the volume pixel value of the test liquid in a single-droplet test liquid; S2. Using a microsyringe to suck a predetermined volume of test liquid, fixing the microsyringe in the syringe fixing groove of the contact angle measuring instrument, and making the microsyringe needle pipe extend into the micro temperature and humidity control box, recording the temperature and relative humidity in the control box, starting the industrial camera photographing function of the contact angle measuring instrument, taking and saving the syringe needle pipe photos, then pressing the microsyringe plunger to hang the droplet, immediately starting the industrial camera photographing function of the contact angle measuring instrument, and taking photos to record the droplet shape at several time points after the droplet is formed; S3. Based on the histogram function of the image processing software, the length pixel value L of the needle tube in the needle tube photo was determined T0 , the width pixel value W of the needle tube T0 , and the height pixel value H of the droplet in the droplet morphology photo Ti , the width pixel value D of the droplet Ti , the area pixel value S of the droplet Ti , and the length pixel value L of the outer needle tube of the droplet Ti ; S4. According to the pixel value determination and calculation method of the volume of the to-be-tested liquid in the droplet, the pixel value V of the volume of the to-be-tested liquid in the droplet at the corresponding time point is determined and calculated according to the calculation formula V Ti =(4 / 3)×π -1 / 2 ×S Ti 3 / 2 ×(D Ti / H Ti ) 1 / 2 -π×(W T0 / 2) 2 ×(L T0 -L Ti ) Ti , and the physical volume of the to-be-tested liquid in the single droplet of the to-be-tested liquid at the corresponding time point is calculated according to the regression relationship equation between the physical volume and the pixel volume of the to-be-tested liquid in the droplet established in S1. S5. Using the physical volume of the test liquid in the droplet determined in S4 at different time points as the ordinate and the corresponding time points as the abscissa to establish a linear regression equation between the physical volume and the time of the test liquid in a single-droplet test liquid, and the slope of the straight line is the evaporation rate of the test liquid. The volume calculation method of the ellipsoid in the step S1 is based on the longitudinal sectional area and the aspect ratio, comprising: by investigating the relationship between the ellipsoid volume V and the aspect ratio D / H of the ellipsoid under the condition that the vertical sectional area S of the ellipsoid is constant, a regression relationship equation V=C×(D / H) of the two is established 1 / 2 , and then the relationship between the constant C and the vertical sectional area S of the ellipsoid and the volume formula of the ellipsoid are investigated, a regression relationship equation C=(4 / 3)×π -1 / 2 ×S 3 / 2 of the two is established, and a calculation formula V=(4 / 3)×π -1 / 2 ×S 3 / 2 ×(D / H) 1 / 2 of the ellipsoid volume based on the vertical sectional area of the ellipsoid and the aspect ratio of the ellipsoid is obtained.

2. The method of claim 1, wherein, The preparation method of the liquid single droplet is as follows: using a 10-microliter flat needle microsyringe to accurately suck a certain volume of test liquid, placing the microsyringe in the syringe fixing groove of the contact angle measuring instrument, pressing the microsyringe plunger, and completely extruding the test liquid in the syringe to form a single-droplet hanging at the lower end of the syringe needle.

3. The method of claim 1, wherein, The liquid volume pixel value measurement and calculation method in the step S4 comprises: using a contact angle measuring instrument and image processing software to measure the area pixel value, width pixel value, height pixel value, needle tube width pixel value and needle tube length pixel value in the droplet, and calculating the volume of the ellipsoid by the formula V=(4 / 3)×π -1 / 2 ×S 3 / 2 ×(D / H) 1 / 2 The volume pixel value of the single droplet is calculated, then the pixel volume of the needle tube in the droplet is calculated by the formula of the volume of the cylinder, and the difference between the two is the liquid volume pixel value in the droplet.

4. The method of claim 1, wherein, The contact angle measuring instrument is equipped with a control system, a sample injection system, a camera system, a stage, and a light source system.

5. The method according to any one of claims 1 to 4, characterized in that, The method is used for determining the evaporation rate of pesticide liquid or aerial spraying aid diluent droplets and evaluating the anti-evaporation performance of the pesticide liquid or aerial spraying aid diluent.

6. A computer processor, comprising: The processor is used to run a program, wherein the program performs the method of any one of claims 1-4 when running.

7. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor performs the method of any one of claims 1-4 when running the program.