• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1994.06b
• /
• pp.19-29
• /
• 1994

Since Winslow (1) has reported an electro - theological (ER) effect which features remarkable and reversible changes in the properties of the fluid due to an imposed external electric field, numerous applications of ER fluids in mechanical devices, such as clutches, control valves, active dampers, and etc. have been proposed to improye dramatical ly their performances (2,3). When the external electric field is imposed to the ER fluid, it behaves as a Bingham fluid, displaying a field dependent yield shear stress which is widely variable. Without the electric field, the ER fluid has a reversible and constant viscosity so that it flows as a Newtonian fluid. Another salient feature of the ER fluid is that the time required for the variation is very short (< 0.001 sec) (4-6). These attractive.characteristics of the ER fluid provide the possibility of the appearance of new engineering technology , for instance, an active vibration control system. Recently, the application of the ER fluid to rotor-bearing systems has been also initiated.

• Journal of electromagnetic engineering and science
• /
• v.5 no.3
• /
• pp.105-111
• /
• 2005

This paper presents the basic characteristics of a cutoff cavity-backed aperture antenna with a feed post and a parasitic post inserted parallel to the aperture. It is shown that this type of antenna forcibly resonates the cutoff cavity by adding a single external reactance to the parasitic post. The Galerkin's method of moments is used to analyze integral equations for the unknown electric current on each post and the aperture electric field on the aperture. The value of an external reactance for forced resonance is analytically obtained by deriving a determining equation. Also the current distribution on each post, aperture electric field distributions, and the radiation patterns are discussed. The theoretical analysis is verified by the measured return loss and radiation patterns.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1374-1377
• /
• 2006

The voltage distribution of an external electrode fluorescent lamp(EEFL) having a gas pressure of 50 torr and a gas composition of Ne:Ar with a ratio of 90:10 has been estimated by varying the distance between the two external electrodes and monitoring the change of the lamp voltage. The estimated voltage gradient, which represents the electric field in the positive column of the EEFL, was very sensitive to the electrode area of EEFL and was in the range of $13\;{\sim}\;27\;V/cm$ at the electrode length of $15\;{\sim}\;31\;mm$. Changing the lamp current in the range $3\;{\sim}\;5\;mA$ did not make noticeable difference in the electric field of the positive column. Theses results may serve as basic data for the optimization of electric and optic characteristics of EEFL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.478-479
• /
• 2008

this paper describes the electric field distribution interpretation along a shield form inner vacuum interrupter(VI). The equipotential line and electric field and field vector in a VI are analysed by a finite element method at various shield form. in result, The equipotential line and electric field distribution was affected to VI shield form. The reason is as it gets distortion of equipotential line done. shield of cup type is how to electric field distribution, finally, this paper recognized whether or not affected, and proposed gap with the most suitable shield length and an external insulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.1
• /
• pp.14-18
• /
• 2007

The electric property in the $GaAs-Al_{x}Ga_{1-x}$ quantum well with the Si ${\delta}-doping$ layer in a non-central position is studied through the effect of the electric field intensity on the electron distribution. The finite difference method is used for the calculation of the subband energy level and its wavefunction. In order to account for the change of the potential energy due to the charged particles, the self consistent method is employed. As the Si ${\delta}-doping$ layer becomes closer to the heterojunction interface, the electrons less affected by Coulomb scattering are greatly increased under the external electric field. Therefore, the high speed device is suggested due to the fact that the high mobility electrons can be increased by positioning the ${\delta}-doping$ layer in the quantum well and by applying the electric field intensity.

• Journal of the Korean Mathematical Society
• /
• v.37 no.6
• /
• pp.977-989
• /
• 2000

In this paper we construct a standing solitary wave solution with prescribed total electric charge to the planer Chern-Simons gauged nonlinear Schrodinger equation with an external electromagnetic field by using a variations method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.189-189
• /
• 2009

This work was focused on the dielectrophoretic force of fullerenes dispersed in liquid crystal host medium, which are investigated in the homogeneously aligned liquid crystal (NLC) cells driven by external electric field. A fullerene of 10 wt% was doped into the LC medium and its electric field induced motion was controlled by both in-plane and vertical electric field. When the electric field was applied, the fullerene start to move in direction of applied electric field. The dark, grey and white states in the proposed device can be obtained by suitable combination of the polarity of applied electric field. The w and l are the width and distance between the electrodes. The reflectance at different l was measured and was found to be increased with increasing l. The dynamical motions of fullerene particles in LC medium suggest that fullerene can be designed for electronic-paper like displays.

• Membrane Journal
• /
• v.12 no.4
• /
• pp.216-225
• /
• 2002

Experimental study on the crossflow electro-microfi1tation of simulated oil emulsion waste water was carried out with polypropylene microfiltration membrane to evaluate the applicability of electrofiltration process in the treatment of oily waste water generated from many industries including nuclear field. The effects of electric field strength transmembrane pressure, crossflow velocity, and oil emulsion concentration on the permeate flux were investigated. In electro-microfiltration process using the external electric field, significant enhancement of permeate flux was achieved by diminishing membrane fouling and it was shown that considerable permeate flux can be maintained for long-term operation compared with conventional membrane filtration process without an electric field.

• Proceedings of the IEEK Conference
• /
• 2004.08c
• /
• pp.787-791
• /
• 2004

We investigated field-effect ion-transport devices based on carbon nanotubes by using classical molecular dynamics simulations under applied external force fields, and we present model schematics that car be applied to the nanoscale data storage devices and unipolar ionic field-effect transistors. As the applied external force field is increased, potassium ions rapidly flow through the nanochannel. Under low external force fields, ther nal fluctuations of the nanochannels affect tunneling of the potassium ions whereas the effects of thermal fluctuations are negligible under high external force fields. Since the electric current conductivity increases when potassium ions are inserted into fullerenes or carbon nanotubes, the field effect due to the gate, which can modify the position of the potassium ions, changes the tunneling current between the drain and the source.

• Journal of Magnetics
• /
• v.16 no.2
• /
• pp.161-163
• /
• 2011

We report results of first principles calculations for effects of an external electric field (E-field) on the magnetocrystalline anisotropy (MCA) in transition-metal (Fe, Co, and Ni) monolayers and at metal-insulator (Fe/MgO) interfaces by means of full-potential linearized augmented plane wave method. For the monolayers, the MCA in the Fe monolayer (but not in the Co and Ni) is modified by the E-field, and a giant modification is achieved in the $Fe_{0.75}Co_{0.25}$. For the Fe/MgO interfaces, the ideal Fe/MgO interface gives rise to a large out-of plane MCA, and a MCA modification is induced when an E-field is introduced. However, the existence of an interfacial FeO layer between the Fe layer and the MgO substrate may play a key role in demonstrating an Efield-driven MCA switching, i.e., from out-of-plane MCA to in-plane MCA.