CN110596476A - Method for rapidly measuring surface bound charge density - Google Patents
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Abstract
The invention discloses a method for rapidly measuring the density of surface bound charges, which comprises the steps of respectively arranging a lower electrode layer and an upper electrode on the upper surface and the lower surface of a bound charge film layer to be measured, grounding the lower electrode layer, electrically connecting the upper electrode layer with the lower electrode layer, serially connecting a load between the upper electrode layer and the lower electrode layer, arranging a conductive liquid drop on the upper surface of the bound charge film layer to be measured, wherein the conductive liquid drop is spread on the upper surface of the bound charge film layer to be measured and generates a current loop when contacting with the upper electrode; and then measuring the current in the current loop when the conductive liquid drop contacts the upper electrode, and further calculating the surface bound charge density of the bound charge film layer to be measured through a pre-constructed calculation model. Through the mode, the method can realize the rapid measurement of the surface bound charge density, and has the advantages of simple required equipment and specific operation, no need of applying external voltage and low cost.
Description
Technical Field
The invention relates to the technical field of surface charge density measurement, in particular to a method for rapidly measuring surface bound charge density.
Background
In some cases (e.g. after contact with an aqueous solution), the surface of the hydrophobic insulating material film layer may spontaneously or by human handling generate a long-standing bound (trapped) charge, which in turn may cause the material film layer to develop a surface potential. The existence of the surface bound charges has great influence on the application of the hydrophobic insulating material in various technical fields, and the function of the hydrophobic insulating material has advantages and disadvantages. On the one hand, in the electrowetting field, surface charges (especially stably existing surface bound charges) can cause a device to generate a surface potential spontaneously under the condition that an applied electric field is zero, so that the controllability of the applied electric field on the function of the device is influenced, and the device is failed. For example, in an electrowetting display, if bound charges are generated on the surface of the hydrophobic insulating layer, the problem that the ink in the pixel cells cannot flow back or the flow back is incomplete is caused. On the other hand, stable surface charges can be effectively utilized in many fields such as micro-nano fluids, bio-protein surface adsorption, water energy collection, and the like. Therefore, the measurement of the bound charges on the surface of the hydrophobic insulating film and the surface potential caused by the bound charges are of great significance in various related fields.
The current measurement of bound charges on the surface of a hydrophobic insulating film can be quantified by measuring the asymmetry of the electrowetting response. Such as the Banpurkar, Arun g., et al, "plasma electric selection of fluorine-water interfaces by electric selection," radar dis-cussions 199(2017):29-47. the value of the voltage at the minimum of the contact angle, i.e., the surface binding potential (Trapping) can be measured by measuring the response of the contact angle of a droplet of liquid on the surface of the film to an applied voltage. The value of the surface charge can be calculated by calculation based on models of Prins and Verheijen (Verheijen, H.J.J., and M.W.J.Prins. "Receplolelecetropicting and applying of charge: model and experiments." Langmuir 15.20(1999): 6616-. The advantages of this method are: the magnitude of the surface binding potential at the contact angle minimum can be visualized by the trend of the contact angle as a function of applied voltage. The disadvantages are that: 1) measurement needs to be performed by applying an external voltage of a triangular wave; 2) the measurement time is longer.
Another commonly used method of measuring surface potential is kelvin probe force microscopy. The Kelvin probe force microscope technology is a method for measuring surface potential through electrostatic force between a probe and a sample, and is characterized in that direct-current bias voltage is applied to a feedback loop to offset the potential on the surface of the sample, and the force applied to the probe is monitored to realize the measurement of the potential value and the distribution on the surface of the sample. The advantages of this test method are: the surface scanning of the surface potential can be realized, and the scanning resolution and the scanning precision are high. The disadvantages are that: 1) the test needs to use an atomic force microscope, the equipment is complex, and the counterfeiting is expensive; 2) the measurement range of the surface potential is limited by the bias voltage range available in the instrument, the bias voltage range available by the current atomic force microscope is +/-10V, and if the surface potential exceeds the bias voltage range, the test result cannot be obtained due to overranging. Therefore, a method which is convenient to operate, low in cost and capable of rapidly measuring the surface bound charges is urgently needed.
Disclosure of Invention
In order to achieve the above object, the present invention provides a method for rapidly measuring the density of surface bound charges.
The technical scheme adopted by the invention is as follows: a method for rapidly measuring surface bound charge density, comprising the steps of:
s1, arranging a lower electrode layer on the lower surface of the bound charge film layer to be detected, and arranging an upper electrode on the upper surface of the bound charge film layer to be detected;
s2, grounding the lower electrode layer, electrically connecting the upper electrode with the lower electrode layer, and connecting a load in series between the upper electrode and the lower electrode layer;
s3, arranging a conductive liquid drop on the upper surface of the to-be-tested bound charge film layer close to the upper electrode, wherein the conductive liquid drop is spread on the upper surface of the to-be-tested bound charge film layer and is in contact with the upper electrode to generate a current loop; measuring the current in a current loop when the conductive liquid drop contacts the upper electrode;
s4, calculating the surface bound charge density of the bound charge film layer to be detected through a pre-constructed calculation model;
the calculation model is as follows:wherein σTIs the surface bound charge density; i.e. i0The current in the current loop is measured when the conductive liquid drop contacts the upper electrode; r is the resistance of the load; cDielThe capacitor is a capacitor of a dielectric layer which comprises the bound charge film layer to be detected and is arranged between a solid-liquid interface of the conductive liquid drop on the surface of the bound charge film layer to be detected and the lower electrode layer; a is the solid-liquid interface area of the conductive liquid drop on the surface of the bound charge film layer to be detected.
The magnitude of the resistance of the load in the circuit directly affects the test current signal. Due to surface bound potential UT＝i0X R, wherein i0Obtaining a current peak value (namely the measured current in a current loop) for a current signal generated when the conductive liquid drop contacts the upper electrode, wherein R is the resistance of the load; theoretically the smaller R, i0Indicated UTThe more accurate. However, the load must not be chosen too small, since the response time of the current is well knownIf R is too small, the response time will be very short, and the existing current testing equipment may not capture the corresponding peak value i of the current0(ii) a In addition, the circuit itself has an internal resistance, i.e. the actual resistance is the sum of the internal resistance of the circuit and the load resistance, and since the internal resistance of the circuit is small and unknown, the resistance of the load generally used is much larger than the internal resistance of the current loop (i.e. R>>RInternal resistance of) Further neglecting the internal resistance of the current loop; the resistance of the load may specifically be greater than or equal to 20 times the internal resistance of the current loop. Of course,if the internal resistance of the current loop is known, this restriction is not present.
Preferably, the conductive liquid droplets are ultrapure water, an aqueous solution, an ionic liquid, or a liquid metal. The aqueous solution may be sodium chloride solution, potassium chloride solution, etc. Preferably, conductive droplets having a conductivity higher than 100. mu.S/cm are used. In the existing surface bound charge density measuring method, the surface bound charge of a hydrophobic insulating film is measured by measuring the asymmetry of electrowetting response for quantification, the test process needs to be carried out in an oil environment, and the surface of the material is oleophilic, so that the material is polluted by oil materials after the test and cannot be used again; this application accessible adopts above electrically conductive liquid drop to measure, avoids placing the constraint charge rete that awaits measuring in oily environment test and lead to the rete pollution.
Preferably, in step S3, the conductive droplet has a volume of 3 μ L to 10 mL.
Preferably, in step S3, a distance D between the installation position of the conductive droplet and the upper electrode is smaller than a solid-liquid contact surface radius r of the conductive droplet after spreading on the bound charge film layer to be tested, and D > r/2.
Preferably, in step S1, the bound charge film layer to be tested is a hydrophobic insulating material layer.
Preferably, the film layer to be tested is a fluoropolymer material film layer. Further preferably, the material of the charge membrane layer to be detected is at least one of PDMS, Teflon AF, Cytop, and Hyflon.
Preferably, in step S1, the thickness of the bound charge film layer to be tested is 10nm to 5 mm.
In step S1, the bottom electrode layer may be any conductive film or plate, and the material thereof may be metal, Indium Tin Oxide (ITO), or two-dimensional conductive material such as graphene; the surface of the electrode layer needs to be flat. And arranging an upper electrode on the upper surface of the bound charge film layer to be detected, wherein the upper electrode cannot cover the whole upper surface of the bound charge film layer to be detected. The upper electrode can be directly attached to the upper surface of the bound charge film layer to be detected or arranged above the upper surface of the bound charge film layer to be detected, and a certain gap is formed between the upper electrode and the bound charge film layer to be detected, but the height of the gap is not higher than that of the conductive liquid drop. The material of the upper electrode can be metal, two-dimensional conductive material, indium tin oxide or heavily doped semiconductor, etc.
Preferably, in step S4, the surface potential of the bound charge film layer to be measured may be further calculated by using a calculation model of the surface potential, where the calculation model of the surface potential is UT＝i0X R, wherein i0The magnitude of the current in the current loop measured when the conductive droplet contacts the upper electrode, R is the resistance of the load.
The beneficial technical effects of the invention are as follows: the invention provides a method for rapidly measuring the density of surface bound charges, which comprises the steps of respectively arranging a lower electrode layer and an upper electrode on the upper surface and the lower surface of a bound charge film layer to be measured, grounding the lower electrode layer, electrically connecting the upper electrode layer with the lower electrode layer, serially connecting a load between the upper electrode layer and the lower electrode layer, arranging a conductive liquid drop at the position, close to the upper electrode, of the upper surface of the bound charge film layer to be measured, wherein when the conductive liquid drop is not in contact with the upper electrode, counter charges caused by the bound charges are all in the lower electrode layer, and when the conductive liquid drop is spread on the upper surface of the bound charge film layer to be measured and is in contact with the upper electrode, the counter charges move from the lower electrode layer to the upper electrode, so that a current; the surface bound charge density of the bound charge film layer to be detected can be calculated through a pre-constructed calculation model by measuring the current in a current loop when the conductive liquid drop contacts the upper electrode. The method can realize the rapid measurement of the surface bound charge density, and has the advantages of simple required equipment and specific operation, no need of applying external voltage and low cost; the problems that in the existing measuring method, the external voltage of a triangular wave needs to be applied and the measuring time is long when the electrowetting asymmetric response method is used for measuring, and the problems that the Kelvin probe force microscope technical equipment is complex and expensive and the measuring range is limited by the internal bias range of the instrument can be solved.
Drawings
In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below.
FIG. 1 is a schematic diagram of the method for rapid measurement of surface bound charge density according to example 1;
FIG. 2 is a partial photograph and equivalent circuit diagram of the conductive liquid drop of FIG. 1 before and after contacting the upper electrode;
FIG. 3 is an equivalent circuit diagram of a calculation model for constructing a surface bound charge density when a conductive liquid droplet contacts an upper electrode in example 1;
FIG. 4 is a graph showing the results of fitting the current model in example 1;
FIG. 5 is a graph showing the results of measuring current signals obtained from samples of different surface bound charge densities in example 2 using the measurement method of example 1 and using a 1.67 M.OMEGA.load with 0.6mol/L NaCl solution as the conductive droplet;
FIG. 6 is a graph showing the results of measuring current signals obtained from samples of different surface bound charge densities in example 2 using the measurement method of example 1 and using a 6.5 M.OMEGA.load with 0.6mol/L NaCl solution as a conductive droplet;
FIG. 7 is a graph of the minimum value of the contact angle of a liquid drop on the surface of a sample measured by the electrowetting asymmetric response method in example 2 as a function of an applied voltage;
FIG. 8 is a graph comparing the results of measuring the binding potential of the sample surface in example 2 using the method of example 1 and the prior art electrowetting asymmetric response method.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
The embodiment provides a method for rapidly measuring the density of surface bound charges, which comprises the following steps:
s1, arranging a lower electrode layer on the lower surface of the bound charge film layer to be detected, and arranging an upper electrode on the upper surface of the bound charge film layer to be detected;
s2, grounding the lower electrode, electrically connecting the upper electrode with the lower electrode layer through a conductive material, and connecting a load resistor in series between the upper electrode and the lower electrode layer;
s3, arranging a conductive liquid drop on the upper surface of the bound charge film layer to be detected, wherein the position is close to the upper electrode; then the conductive liquid drop gradually spreads and deforms on the upper surface of the bound charge film layer to be detected, and contacts with the upper electrode to generate a current loop; at the moment, the current of the current loop is measured when the conductive liquid drop contacts the upper electrode;
s4, calculating the surface bound charge density of the bound charge film layer to be measured through a pre-constructed calculation model;
the calculation model isWherein σTIs the surface bound charge density; i.e. i0The current in the current loop is measured when the conductive liquid drop contacts the upper electrode; r is the resistance of the load; cDielThe capacitor is a capacitor of a dielectric layer which comprises the bound charge film layer to be detected and is arranged between a solid-liquid interface of the conductive liquid drop on the surface of the bound charge film layer to be detected and the lower electrode layer; a is the solid-liquid interface area of the conductive liquid drop on the surface of the bound charge film layer to be detected.
The specific principle of the above measurement method is shown in fig. 1 and 2. Fig. 1 (a) is a schematic diagram of a conductive droplet disposed on a bound charge film layer to be measured, and the conductive droplet is not in contact with an upper electrode, and (b) is a schematic diagram of the conductive droplet in contact with the upper electrode. Fig. 2 (a) is a partial photograph taken from directly above when the conductive liquid droplet in fig. 1 does not contact the upper electrode (top view), and (b) is a partial photograph taken from directly above when the conductive liquid droplet in fig. 1 contacts the upper electrode (top view); (c) an equivalent circuit diagram before the conductive liquid drop contacts the upper electrode; (d) is an equivalent circuit diagram when the conductive liquid drop is contacted with the upper electrode.
As shown in fig. 1 (a) and fig. 2 (a), a lower electrode layer 2 is disposed on the lower surface of a bound charge film layer 1 to be measured, an upper electrode 3 is disposed on the upper surface, the lower electrode layer 2 is grounded, the upper electrode 3 is electrically connected with the lower electrode layer 2, a load resistor 4 and an ammeter 5 are connected in series between the upper electrode 3 and the lower electrode layer 2, and the ammeter 5 is used for measuring the current in the circuit; the conductive liquid drop 6 is arranged on the upper surface of the bound charge film layer 1 to be detected and close to the upper electrode 3. When the conductive liquid droplet 6 does not contact the upper electrode 3, as shown in fig. 1 (a) and fig. 2 (a) and (c), the antagonistic charges 8 due to the bound charges 7 are all in the lower electrode layer 2. When the conductive liquid drop 6 spreads on the upper surface of the bound charge film layer 1 to be measured and contacts with the upper electrode 3, as shown in fig. 1 (b), fig. 2(b) and (d), the counter charge 8 is transferred from the lower electrode layer 2 to the upper electrode, thereby generating a current loop and forming a current signal. At this time, the current magnitude (i.e., the current peak value) in the current loop when the conductive liquid droplet 6 contacts the upper electrode 3 can be measured by the ammeter 5, and the surface bound charge density of the bound charge film layer 1 to be measured can be calculated by the calculation model of the surface bound charge density.
For the construction of the calculation model of the surface bound charge density, please refer to fig. 3, fig. 3 is an equivalent circuit diagram of the conductive liquid drop contacting the upper electrode, which corresponds to (b) in fig. 1 and (b) and (d) in fig. 2. Wherein the content of the first and second substances,is a surface potential; sigmasIs the surface charge density; sigmaTIs the surface bound charge density; q is a surface charge; a is the solid-liquid interface area of the conductive liquid drop on the surface of the bound charge film layer to be detected;at the lower electrode layer potential, since the lower electrode layer is grounded, it isAnd R is a load resistor. Surface potentialWherein, CACapacitance per unit area, CA＝ε·ε0D (where ε is the relative permittivity of the dielectric,. epsilon.,0of vacuum dielectric constant, d being a dielectric film layerThickness); in addition, the first and second substrates are,and C is the total capacitance of the circuit. The specific derivation calculation is as follows:
because:
and:
therefore:
namely:
and because: q ═ idt;
the formula is substituted as follows:
two-sided calculus:
integration on both sides:
wherein, C1Is a constant;
namely:wherein Const is a constant;
when the conductive droplet has just contacted the upper electrode,
therefore, Const is UT/R；
Namely:
by using the above measuring method, the current model is used by changing the loadFitting was performed to verify the validity of this model. Specifically, the results of the experiments using loads having resistances of 1.65M Ω, 3.3M Ω, 6.5M Ω, 11.5M Ω, and 24M Ω, respectively, are shown in fig. 4. In fig. 4, (a) - (e) show a comparison graph of the measured current of each load with time and a current model, wherein we mainly focus on the lower peak value of the current, and it can be known that the measured current value is basically consistent with the current model value, which proves that the above model is effective, so that the model can be used for calculating the surface potential and the surface bound charge density. In fig. 4, (f) shows a change in measured current (lower peak value) at different load resistances, and the Model broken line indicates that the Model I is UTAs can be seen from fig. 4 (f), the current value changes at different load resistances all correspond to I ═ UT(ii)/R, indicating that U can be calculated by I and R in this wayT。
Because when t is equal to 0,equal to 1, so that it can be presumed that the instantaneous current when the conductive droplet contacts the upper electrode reaches the maximum value. Therefore, in the actual measurement operation process, the calculation formula of the current in the current loop when the conductive liquid drop contacts the upper electrode is as follows: i.e. i0＝UTR (equation 2).
In addition, please refer to (c) and (d) of FIG. 2, which are disposed on the bound charge film layer to be testedThe conductive liquid drops form a double-electric layer, and a dielectric layer is formed between a solid-liquid interface on the surface of the bound charge film layer to be detected and the lower electrode layer and between the solid-liquid interface and the lower electrode layer and containing the bound charge film layer to be detected; cEDLIs an electric double layer (electric double layer) capacitor, CDielThe capacitor is a capacitor of a dielectric layer which comprises the bound charge film layer to be detected and is arranged between a solid-liquid interface of the conductive liquid drop on the surface of the bound charge film layer to be detected and the lower electrode layer. C since the thickness of the electric double layer is very small compared to the dielectric layerEDLFar greater than CDiel(i.e. C)EDL>>CDiel). The total capacitance C of the circuit is 1/(1/C)EDL+1/CDiel)≈CDiel(formula 3); therefore, CEDLThe effect in the overall circuit is negligible.
Combining the formulas 1-3, the calculation model of the surface bound charge density is obtained as follows:wherein σTIs the surface bound charge density; i.e. i0The current in the current loop is measured when the conductive liquid drop contacts the upper electrode; r is the resistance of the load; cDielThe capacitor is a capacitor of a dielectric layer which comprises the bound charge film layer to be detected and is arranged between a solid-liquid interface of the conductive liquid drop on the surface of the bound charge film layer to be detected and the lower electrode layer; a is the solid-liquid interface area of the conductive liquid drop on the surface of the bound charge film layer to be detected.
Therefore, the surface bound charge density of the bound charge film layer to be measured can be obtained according to the calculation model of the surface bound charge density by measuring the current in the current loop when the conductive liquid drop contacts the upper electrode by adopting the method.
Further, the calculation model of the surface potential obtained by the above equation 2 is UT＝i0And x R, so that the surface potential of the bound charge film layer to be detected can be obtained according to a calculation model of the surface potential by measuring the current in a current loop when the conductive liquid drop contacts the upper electrode by adopting the method.
Example 2
The measurement was performed on samples having different surface bound charge densities by the method of example 1, wherein the conductive droplets were measured on each sample (samples 1 to 4) with different loads (resistances of 1.67M Ω and 6.5M Ω, respectively) using 0.6mol/L NaCl solution, and the results are shown in fig. 5 and 6, respectively. Fig. 5 (a) is a graph showing the current signal results obtained by performing a plurality of measurements on each sample using a 1.67M Ω load, and (b) is an enlarged schematic view showing the results obtained by performing the measurement on each sample; the current of the current loop is calculated as the lower peak value when the conductive liquid drop contacts the upper electrode; fig. 6 is a graph of the current signal results from multiple measurements on each sample using a 6.5M Ω load. As can be seen from fig. 5 and 6, when the measurement is performed for a plurality of times by using the above measurement method, the fluctuation of the measurement result is small, which indicates that the stability of the measurement method is good. Through the measured current magnitude, the surface bound charge density and the surface potential of each sample can be obtained according to a calculation model of the surface bound charge density and the surface potential.
In addition, the surface potentials and the surface charge densities of the samples 1-4 are measured by adopting the existing electrowetting asymmetric response method, wherein the adopted liquid drop is 1 mu L of pure water; the results are shown in FIG. 7 and Table 1.
TABLE 1 surface potential and surface charge density (average) of each sample measured by electrowetting asymmetric response method
| Sample (I) | Surface potential UT(V) | Surface charge density (mC/m)2) |
| Sample 1 | -2 | 0.03 |
| Sample 2 | -6 | 0.09 |
| Sample 3 | -18 | 0.27 |
| Sample No. 4 | -34 | 0.52 |
The results obtained by comparing the results obtained above using the measurement method of example 1 with those obtained using the electrowetting asymmetry response method are shown in FIG. 8, in which the model line represents the results obtained using example 1 (in terms of i)0＝UTcalculated/R), each point value is the result measured by the electrowetting asymmetric response method. As can be seen from fig. 8, the measurement result obtained by the electrowetting asymmetric response method is on (or near) the model line, and it can be seen that the measurement result obtained by the measurement method in example 1 is consistent with that obtained by the conventional electrowetting asymmetric response method, but the measurement method in example 1 of the present application is simpler and can be measured in a shorter time than that obtained by the conventional electrowetting asymmetric response method.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A method for rapidly measuring the density of surface bound charges is characterized by comprising the following steps:
s1, arranging a lower electrode layer on the lower surface of the bound charge film layer to be detected, and arranging an upper electrode on the upper surface of the bound charge film layer to be detected;
s2, grounding the lower electrode layer, electrically connecting the upper electrode with the lower electrode layer, and connecting a load in series between the upper electrode and the lower electrode layer;
s3, arranging a conductive liquid drop on the upper surface of the to-be-tested bound charge film layer close to the upper electrode, wherein the conductive liquid drop is spread on the upper surface of the to-be-tested bound charge film layer and is in contact with the upper electrode to generate a current loop; measuring the current in a current loop when the conductive liquid drop contacts the upper electrode;
s4, calculating the surface bound charge density of the bound charge film layer to be detected through a pre-constructed calculation model;
the calculation model isWherein σTIs the surface bound charge density; i.e. i0The current in the current loop is measured when the conductive liquid drop contacts the upper electrode; r is the resistance of the load; cDielThe capacitor is a capacitor of a dielectric layer which comprises the bound charge film layer to be detected and is arranged between a solid-liquid interface of the conductive liquid drop on the surface of the bound charge film layer to be detected and the lower electrode layer; a is the solid-liquid interface area of the conductive liquid drop on the surface of the bound charge film layer to be detected.
2. The method for rapidly measuring the density of bound charges on a surface according to claim 1, wherein the conductive liquid droplet is ultrapure water, an aqueous solution, an ionic liquid or a liquid metal.
3. The method for rapidly measuring the density of surface bound charges according to claim 2, wherein the volume of the conductive droplet is 3 μ L to 10mL in step S3.
4. The method for rapidly measuring the density of bound charges on the surface according to claim 1, wherein in step S3, the distance D between the position where the conductive liquid drop is disposed and the upper electrode is smaller than the solid-liquid contact surface radius r of the conductive liquid drop after spreading on the bound charge film layer to be measured, and D > r/2.
5. The method of claim 1, wherein the load has a resistance greater than or equal to 20 times an internal resistance of the current loop.
6. The method of claim 1, wherein in step S1, the bound charge film to be measured is a hydrophobic insulating material layer.
7. The method as claimed in claim 6, wherein the film layer to be measured is a fluoropolymer film layer.
8. The method for rapidly measuring the density of the surface bound charges according to claim 7, wherein the material of the charge film layer to be measured is at least one of PDMS, Teflon AF, Cytop and Hyflon.
9. The method of claim 1, wherein in step S1, the thickness of the bound charge film to be measured is 10nm to 5 mm.
10. The method for rapidly measuring the density of bound charges on the surface according to any one of claims 1 to 9, wherein step S4 further comprises calculating the surface potential of the bound charge film layer to be measured through a calculation model of the surface potential; the calculation model of the surface potential is UT＝i0X R, wherein i0The magnitude of the current in the current loop measured when the conductive droplet contacts the upper electrode, R is the resistance of the load.
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| CN113268878A (en) * | 2021-05-28 | 2021-08-17 | 华南师范大学 | Transient current analysis method, system, equipment and storage medium for nonpolar liquid |
| CN113406708A (en) * | 2021-06-18 | 2021-09-17 | 中国科学院地质与地球物理研究所 | Electrode range eliminating system and method for electromagnetic prospecting electric field measurement |
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| CN113268878A (en) * | 2021-05-28 | 2021-08-17 | 华南师范大学 | Transient current analysis method, system, equipment and storage medium for nonpolar liquid |
| CN113268878B (en) * | 2021-05-28 | 2022-11-08 | 华南师范大学 | Transient current analysis method, system, equipment and storage medium for nonpolar liquid |
| CN113406708A (en) * | 2021-06-18 | 2021-09-17 | 中国科学院地质与地球物理研究所 | Electrode range eliminating system and method for electromagnetic prospecting electric field measurement |
| CN113406708B (en) * | 2021-06-18 | 2022-01-04 | 中国科学院地质与地球物理研究所 | Electrode range eliminating system and method for electromagnetic prospecting electric field measurement |
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