• Journal of the Korean Applied Science and Technology
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• v.16 no.3
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• pp.193-198
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• 1999

Maxwell displacement current(MDC) measuring technique has been applied on the study of monolayers of fatty acid. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about $130{\AA}^2$. MDCs were investigated in connection with monolayer compression cycles. It was found that the current pulses were generated over the entire range of molecular area, and the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. We investigated the change in absorption spectra of the fatty acid(8A5H) monolayer LB film due to cis-trans photoisomerization. It was found that the absorption spectrum of the 8A5H LB film was induce to photoisomerization by alternate irradiation with UV and visible light irradiation.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.215-217
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• 1996

We have examined the electrical properties of arachidic acid Langmuir(L)films by using a displacement-current-measuring technique with pressure stimulation, displacement current peak appeared at a area per molecule around $90{\AA}^2$, possibly due to the orientational change in hydrophobic part of arachidic acid molecules. The displacement current is the transient current, it is generated when charged particles existing in single monolayers are displaced with the external stimulation. In this report, we mainly describe the displacement current generation from arichidic acid monolayers with pressure stimulation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.72-78
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• 2009

We have developed a current range extension method to obtain the ratio error and phase displacement of a current transformer (CT) by using absolute evaluation method and two different CTs. The method was applied to CTs under test with the current ratios in the range of 5,000 A / 1 A - 20,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Germany using the same CT under test within an expanded uncertainty (k = 2) in the overall current ratios.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.7
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• pp.339-345
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• 2000

This paper deals with the displacement estimation of magnetically suspended simple 1 DOF(degree of freedom) system without the displacement sensor. Inherently electro-magnet for control has two natural feedback loops. One is the transfer function which represents the dependance of the amount of the magnetic flux on the gap displace-ments. The other is the transfer function expressing the properties that the back electromotive force is derived from the time derivative of the magnetic flux. Through these two feedback loops, information about the gap length can be represented by the magnetic flux and the coil current. This means that the gap length can be detected from these two states variables of the electromagnet without a displacements sensor(self-sensing). The displacement can be estimated with the magnetic flux subtracted by the coil current. In this paper we use a balance beam in order to deal with the displacement sensorless estimation of the magnetic bearing system. For the stable estimation of the gap displacements by using the method of self-sensing simple PD controller is used. We first show the mathematical model of the balance beam, and then we show the effectiveness of the current and flux feedback for making stable estimation of the gap displacements for the balance beam. Simulation results show the effectiveness of the current and flux feedback for good estimation of the displacement without using displacement sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.38-42
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• 2001

To observe the Langmuir films, displacement current measuring system(Nippon Laser & Electronics), $\pi-A$ isotherms measuring device, and Brewster Angle Microscope(BAM) were used. As results, for 8A5H, big tilt angle changes of many molecules were detected before liquid expanded phase when the monolayer was compressed and expanded by barrier. Also many small and bright points were detected by BAM when the displacement current radically changed. In $\pi$-A isotherms, surface pressure of 8A5H was radically decreased between 35 and 40[mN/m] and monolayer was assumed to be collapsed in solid condensed phase, since large bright domain was observed without change of displacement current and this bright boundary was not classified part of domain in BAM image. If we observe behaviors of molecules on the water surface in these three measurement at the same time, we can get more precise informations on L films and it could be good data for fabricating LB films.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1413-1415
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• 2002

The Displacement current measurement system used in this experiment because detecting the dynamic behavior of monolayers at the air-water interface is possible. It basically consists of a film balance, a pair of electrodes connected to each other through a sensitive ammeter. Here, one electrode is suspended in air and the other electrode is placed in the water. PBLG phase transformation measured by Maxwell-displacement-current-measurement method in surface of the water. Measured (surfacc pressure, displacement current and dipole moment) of monolayers of PBLG on the water surface. We measured displacement current that occur when changed temperature(15, 20, 25$^{\circ}$ ) and the compression speed(30, 40, 50(mm/min)). From the result, it is known that curren generated in the range of high surface pressur compression velocity and temperature become faste.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.385-388
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• 1997

We hate examined the electrical properties of L-${\alpha}$-DLPC Langmuir(L) films by using a displacement current measuring technique with pressure stimulation. Displacement current was generated when the sample spread volume was about 280${\mu}\ell$, 360${\mu}\ell$ and compression velocity was about 30, 40, 50mm/min. Displacement current was generated in the range of gas state, gas/fluid state and fluid state in the course of monolayer compression. From the result, it is known that displacement current is generated in the range of high surface pressures as compression velocity become faster.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.491-494
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• 2000

Conductive Langmuir-Blodgett(LB) films have recently attracted much interest from the viewpoint of ultrathin film conductors at the molecular level. The result shows that the Maxwell-displacement-current(MDC) measuring technique is useful in the detection of phase-transition over the entire range of molecule areas. At the liquid-solid phase transition, a striking feature in the present current measurement was observed; the I-A isotherm for a DPPC monolayer has sharp bend. Dynamic behavior of monolayers in the presence of an external field was also investigated using the current-measuring technique. Dynamic behavier of DPPC monolayer was measured by displacement current when the molecules are stimulated by pressure velocity. As result, it is known that current is generated of higher current pe마 as compression velocity become faster. Also, in order to clarify the reorganization of the lipid monolayers, it is instructive to plot the relationship between I and 1/$A^2$.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2032-2033
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• 2008

We have developed an evaluation technique for phase displacement of current transformer (CT) comparator by using the precise standard capacitors and resistors. By applying this technique for equivalent circuit of CT comparator evaluation system, we can obtain the calculated and measured phase displacement in the CT comparator. Thus we can evaluate phase displacement of CT comparator by comparing the calculated and measured phase displacement. The method was applied to CT comparator under test with the phase displacement ranges of $0{\sim}{\pm}7.5$ crad. Finally we have compared the phase displacement of the CT comparator under test theoretically obtained in this method with the specification.

• Journal of Science Education
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• v.45 no.2
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• pp.219-230
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• 2021

In this study, we derived several formulas for magnetic fields and induced voltages in a parallel plate capacitor biased by DC voltages. The computer simulation based on the derived formulas reveals that the magnetic fields due to the displacement current fall within the range of 10^-10T to 10^-9T and thence the experiment for the displacement current is not possible because the magnetic field sensor used in Data Logger could measure the magnetic fields of above 10^-5T range. Contrary to this, the computer simulation confirms that the induced voltages in a toroidal coil due to the displacement current range measurable values of 0.002~0.021V. The results imply that the displacement current can be confirmed by measuring the induced voltages in a toroidal coil inserted into a parallel plate capacitor under DC biasing.