• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.637-637
• /
• 2013

We develop single-crystal poly(3,4-ethylenedioxythiopene nanowires using liquid-bridge-mediated nanotransfer printing via vapor phase polymerization. This direct printing method can simultaneously enable the synthesis, alignment and patterning of the nanowires from molecular ink solutions. Twoor three-dimensional complex structures of various single-crystal organic nanowires were directly fabricated over a large area using many types of molecular inks. This method is capable of generating several optoelectronic devices. LB-nTM is based on the direct transfer of various materials from a mold to a substrate via a liquid bridge between them. To demonstrate its usefulness, we used LB-nTM to fabricate nanowire field-effect transistors and arrays of 6,13-bis (triisopropyl- silylethynyl) pentacene (TIPS-PEN) nanowire field-effect transistors.

• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.3-5
• /
• 1999

The 4-pole LHSM was composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. Three dimensional model of LHSM provided the equivalent reluctance and PM model for 2D FEA. From these 2D FEA models, when the motor was fed by DC and 3-phase currents, the magnetic field were calculated and compared with the results of 3D FEA.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.439-441
• /
• 2003

In this study the formula of electro magnetic fields under 3-phase power lines with vertical or horizontal line-configurations were deduced and the effect of the earth was considered in the formula. Using the formula the electric field and the magnetic flux density under distribution and transmission lines constucted currently in our country were calculated and the components of each field were investigated with horizontal distance from tower and height above the earth.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.460-463
• /
• 2003

We report the microwave reflection coefficient $S_{11}$ of copper(II)-phthalocyanine(CuPc) using a near-field microwave microscope(NSMM) in order to understand the intrinsic electromagnetic properties of organic materials. For a NSMM system, a high-quility microstip resonator coupled with a dielectric resonator was used. The reflection coefficient $S_{11}$ was changed by the preparation conditions of CuPc thin films. We compared the reflection coefficient with crystal phase, surface morphology, UV absorption spectra and x-ray diffraction results.

• KSTLE International Journal
• /
• v.8 no.2
• /
• pp.21-25
• /
• 2007

The electrorheological effect of the suspension composed of Bismark Brown chitosan succinate as the dispersed phase in silicone oil was investigated. Bismark Brown chitosan succinate suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 1.84 power on the electric field. The experimental results for the suspension correlated with the polarization model and Bismark Brown chitosan succinate suspension behaved as an anhydrous ER fluid. On the basis of the results, Bismark Brown chitosan succinate suspension showed the ER flow behavior upon application of the electric field due to the polarizability of the branched amide and amine polar groups of the Bismark brown chitosan succinate particles.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1329-1334
• /
• 2001

This paper deals with the application of a sound-ray method to the analysis of the sound field in an ultrasonic cleaner. In order to include the wave interference phenomenon, the method has been modified to consider the phase of sound rays, The improved algorithm has been implemented by developing a Visual C＋＋ program, The algorithm has been verified by comparing the analysis results of BEM reported earlier. It has been shown that the algorithm can be used to calculate ultrasonic fields in a cleaning- container with an object to be cleaned.

• Journal of Ocean Engineering and Technology
• /
• v.22 no.2
• /
• pp.7-12
• /
• 2008

A far field solution of the slowly varying force on an offshore structure by gravity ocean waves was shown as a function of the reflection and transmission of the body disturbed waves. The solution was obtained from the conservation of the momentum flux, which simply describes various wave forces, while making it unnecessary to compute complicated integration over a control surface. The solution was based on the assumption that the frequency difference of the bichromatic incident waves is small and its second order term is negligible. The final solution is expressed in term of the reflection and transmission waves, i.e. their amplitudes and phase angles. Consequently, it shows that not only the amplitudes but also the phase differences make critical contributions to the slowly varying force. In a limiting case, the slowly varying force solution gives the one of the mean drift force, which is only dependent on the reflection wave amplitude. An approximation is also suggested in a case where only the mean drift force information is available.

• Structural Engineering and Mechanics
• /
• v.74 no.3
• /
• pp.425-434
• /
• 2020

The present paper is concerned at investigating the effect of hydrostatic initial stress, gravity and magnetic field in fiber-reinforced thermoelastic solid, with variable thermal conductivity. The formulation of the problem applied in the context of the three-phase-lag model, Green-Naghdi theory with energy dissipation, as well as coupled theory. The exact expressions of the considered variables by using state-space approaches are obtained. Comparisons are performed in the absence and presence of the magnetic field as well as gravity. Also, a comparison was made in the three theories in the absence and presence of variable thermal conductivity as well as hydrostatic initial stress. The study finds applications in composite engineering, geology, seismology, control system and acoustics, exploration of valuable materials beneath the earth's surface.

• Journal of the Optical Society of Korea
• /
• v.7 no.2
• /
• pp.119-125
• /
• 2003

We demonstrate parametric resonance in a magneto-optical trap. When we modulate the intensity of the cooling laser at about twice the resonant frequency of the trap, the atoms in the trap are divided into two parts and oscillate with 180 degree phase difference with the finite length due to nonlinearity of the trap potential. These are the effects of general nonlinear dynamics, called the Hopf bifurcation, or limit cycle motion. The amplitude and the phase of the oscillations are measured and compared with the theoretical calculations based on simple Doppler cooling theory. The experimental results are in excellent agreement with the simulation results based on the simple Doppler cooling theory.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.146-149
• /
• 2003

To control the position, velocity and torque of the ultrasonic motor, a great variety of method are proposed such as the amplitude, phase difference, frequency and so on. In the case of phase difference method, it has some advantages: it can control the direction and velocity of rotation only adjusting the phase difference and it has wide control-band. During the USM driving on adjusting phase difference, its characteristic was transformed by the change of resonance-frequency of stator, which means that the resonance frequency is different according to the phase difference. Consequently, we need to set up the most suitable driving frequency according to each phase difference.