Device for measuring liquid absorption coefficient under condition of external electric field

[0038] Example 1

[0039] Use as figure 2 Device for measurement. Due to the large surface tension of the liquid, if the measuring cylinder is used for measurement, part of the liquid will remain in the measuring cylinder, which will affect the accurate measurement of the thickness of the liquid. Therefore, in this embodiment, a syringe is used to measure a certain amount of the liquid to be measured and put it into the quartz sample cell 20 in. After the liquid is evenly spread in the sample cell 20, the positive and negative electrodes of the DC power supply are respectively connected to the platinum wires on the sample cell 20, and the DC power supply voltage is set to 0V. In order to improve the accuracy of the test results, it is necessary to ensure that no bubbles exist in the light-transmitting range of the middle area of ​​the sample cell 20 during the test. If bubbles exist in the liquid, they can be pierced with a needle. Put the quartz sample cell 20 into the spectrometer. If the sample chamber itself is not in a horizontal position, a gasket should be placed on one end of the sample cell as needed. The thickness and placement angle of the gasket are calculated according to the sample cell size, so that the sample cell 20 is The sample chamber is placed horizontally. After everything is ready, start measuring the liquid transmittance according to the experimental operating steps of the spectrometer. In order to ensure the accuracy of the measurement, the voltage gradually rises from 0V and cannot be adjusted back during the boost process. Before each measurement, run stably at the same voltage for 3 minutes before starting the measurement, starting from low to high. When it is found that the voltage exceeds a certain value, the liquid to be tested changes color or overflows with odor, the measurement ends. If the above phenomenon has not occurred, the measurement ends when the electric field strength increases to 60V/m. Record the transmittance of the liquid at different voltages as a function of wavelength.

[0040] After using a spectrometer to measure the change curve of transmittance with spectrum, the absorption coefficient is obtained by inversion according to Bougel's law. Since the incident light is close to the vertical incidence, the reflection effect of the glass and liquid interface is not considered.

[0041] Before carrying out the experiment, measure the absorption coefficient of the empty sample cell as a control. Since the thickness of the sample cell glass is uniform, the radiation intensity I after the incident light passes through the sample cell 1 Satisfying formula 1, the spectral transmittance ρ of incident light after passing through the empty sample cell 1 Satisfy formula 2, according to formula 1 and formula 2, the absorption coefficient k of the glass can be calculated 1λ.

[0042] I 1 = I 0 ·Exp(-k 1λ L) Formula 1

[0043] Where I 0 Is the radiation intensity of the incident light, L is the distance between the two parallel sides of the sample cell in the direction of the incident light, k 1λ Is the absorption coefficient of glass.

[0044] ρ 1 = I 1 I 0 Formula 2

[0045] When the sample cell is filled with liquid, the radiation intensity of incident light after passing through the liquid I 2 Satisfy formula 3, the spectral transmittance of liquid ρ 2 If formula 4 is satisfied, the absorption coefficient of the liquid can be obtained according to formula 4.

[0046] I 2 = I 1 ·Exp(-k 2λ L 2 ) Formula 3

[0047] ρ 2 = I 2 I 0 = I 1 · exp ( - k 2 λ L 2 ) I 0 = ρ 1 · exp ( - k 2 λ L 2 ) Formula 4

[0048] Where k 2λ Is the absorption coefficient of the liquid; L 2 Is the thickness of the liquid in the direction of the incident light, L 2 It can be directly measured with a vernier caliper, or obtained by measuring the volume of liquid.

[0049] Figure 4 It is the spectral transmittance curve of incident light passing through the empty sample cell when the applied voltage is 1V in this embodiment, Figure 5 It is the spectral transmittance curve of the liquid when the applied voltage is 1V in this embodiment. It can be seen from the smoothness and Rayleigh property of the curve that the test result is accurate and the test accuracy is good.