• Electrical & Electronic Materials
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• v.7 no.3
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• pp.213-219
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• 1994

Cu compensated Si doped GaAs (GaAs :Si:Cu has been chosen as the switch material. The GaAs material has been characterized by DLTS(Deep Level Transient Spectroscopy) technique and the obtained data were used in the computer simulation. Simulation studies are performed on several GaAs switch systems, composed of different densities of Cu, to investigate the influence of deep traps in the switch systems. The computed results demonstrates important aspect of the switch, the existence of two stable states and fast optical quenching. An important parameter optimum Cu density for the switch are also determined.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.389-394
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• 2017

The limitation of flow control for a bistable fluidic valve has been investigated. The physical model of the fluidic valve includes two main flow outlets and two control flow inlets. The experiments were conducted with pressure regulators, mass flow meters, and piezo sensors to analyze flow switching characteristics of the fluidic valve. The experimental data such as pressure and mass flow rate of control flows and the switching time of the main flow was obtained with various operating conditions. The operation limit of the fluidic valve is identified, and a model equation for pre-estimating the minimum control pressure to switch the direction of the main flow has been proposed.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.130-134
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• 2000

In this paper, the configuration of a reflectIve bistable tWIsted nematic (BTN) liquid crystal cell is optmnzed for high contrast and high brightness operation. We searched for the optimum opncal parameters of a reflective BTN cell by calculating its optical performances at 3 wavelengths; red, green, and blue. By studying the effect of each optical parameter on the optical performances, we found that the angle of !he polmlzer IS more important than any other opnea! parmlleters iu the deSIgn of a reflective BTN cell. We fablicated a reflective BTN cell with a wide-band retardation Him, whose measmed contrast ratio is 10.6: 1. .6: 1.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.374-374
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• 2010

Charge transfer mechanism of poly(4,4'-aminotriphenylene hexafluoroisopropylidenediphthalimide) (TP6F PI) which exhibits bistable ON and OFF switching has been studied using photoemission electron spectroscopy (PES) and near-edge x-ray absorption fine structure (NEXAFS). Here, we demonstrate novel set-up in which holes are injected by photoemission process instead of direct charge carrier injection via metal electrode. The accumulated charges on the PI surface in the OFF state abruptly flow across the PI film when the bias voltage of a back electrode reaches a specific value, indicating that the film is changed to the ON state. Core level and x-ray absorption spectra probed at charge injection region via photoemission process do not show any evidences implying structural modification of TP6F PI during the phase change. Whereas, in valence band spectra, the highest occupied molecular orbital (HOMO) is shifted toward Fermi level, responsible for improved hole-mobility of TP6F PI of ON state.

• Journal of Magnetics
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• v.10 no.3
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• pp.113-117
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• 2005

Some polycrystalline ferromagnetic mms are composed of continuously connected nanometer scale islands with random crystallite orientations. The nanometer perturbations of the mm introduce a large number of nearly degenerate local field configurations that are indistiguishable on a macroscopic scale. As a first step, this situation is modelled as a thin ferromagnetic disc coupled by exchange and dipole interactions to a homogeneous ferromagnetic plane, where the disc and plane have different easy axes. The model is solved to find the partial $N\acute{e}el$ domain walls that minimize the magnetic energy. The two solutions give a bistable configuration that, for appropriate geometries, provides an important microsopic ferromagnetic degree of freedom for the mm. These results are used to interpret recent measurements of exchange biased bilayer films.

• Structural Engineering and Mechanics
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• v.89 no.6
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• pp.571-578
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• 2024

The bistable thin cylindrical shell is developable structure with the ability to transition between its two stable configurations. This structure offers significant potential applications due to its excellent deformability. In this paper, the composite thin cylindrical shell consisting of the composite layer and the piezoelectric layer was investigated. The material and geometric parameters of the shell were found to influence its stable characteristics. The analysis model of the composite thin cylindrical shell incorporating the piezoelectric layer was developed, and the expressions for its strain energy were derived. By applying the minimum energy principle, the impact of the electric field intensity on the bi-stable behaviors of the cylindrical shell was analyzed. The results showed that the shell exhibited the bistability only under the appropriate electric field strength. And the accuracy of the theoretical prediction was verified by simulation experiments. This study provides an important reference for the application of deployable structures.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.355-355
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• 2009

• Proceedings of the Korean Nuclear Society Conference
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• 2003.10a
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• pp.227.2-227.2
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.122.1-122
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• 1998

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.8
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• pp.1-11
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• 2002

A multi-section DFB-LD shows optical bistability subject to externally injected light signal, then it has potential applications such as wavelength conversion and optical logic gates. In this paper, we have studied the optical bistability in multi-section DFB-LD using split-step time-domain model. It is confirmed that the multi-section DFB-LD, which is excited inhomogeneously, shows bistability. The optical bistable characteristics are investigated when input light is injected into a absorptive region. Simulation results show that multi-section DFB-LD works as a flip-flop depending on the set-reset optical pulse which has a few ns in switching time and a few pj in switching energy, so that it can act as a optical logic device. Besides, if we change the carrier lifetime and the differential gain coefficient, it is expected that the response time of optical output signal can be reduced.