• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.292-297
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• 2001

Twin screw extruders are the heart of the polymer processing industry. They are used at some stage in nearly all polymer processing operations. This paper is concerned with the basic elements of the extruder design. The proper design of the geometry of the extruder screw is of crucial importance to the proper functioning of the extruder. If the material transport instabilities occur as a result of improper screw geometry, even the most sophisticated computerized control system cannot solve the problem. For this purpose, a characteristic design on flights shape of the extruder screw. This paper presents cross section designs of a closely intermeshing twin screw extruder with double-flighted screw elements, and channel depth characteristics for a double flighted corotating self-wiping twin screw extruder.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.295-300
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• 1996

In this study, the dynamic instabilities of a nonlinear elastic system subjected to follower force are investigated. The two-degree-of-freedom double pendulum model with nonlinear geometry, cubic spring, and linear viscous damping is used for the study. The constant and periodic follower forces are considered. The chaotic nature of the system is identified using the standard methods, such as time histories, phase portraits, and Poincare maps, etc.. The responses are chaotic and unpredictable due to the sensitivity to initial conditions. The sensitivities to parameters, such as geometric initial imperfections, magnitude of follower force, and viscous damping, etc. is analysed. The strange attractors in Poincare map have the self-similar fractal geometry. Dynamic buckling loads are computed for various parameters, where the loads are changed drastically for the small change of parameters.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.373-377
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• 1999

HTS magnet operated at 20${\sim}$40 K was fabricated using three pieces of 100 m Bi-2223 high temperature superconductors fabricated by powder-in-tube process. It was composed of 6 double pancakes with 75 ID. and 113 OD. connected by lab splice. Coil I$_c$ of each DP.(double pancake) obtained for a 140 turn, fabricated using react and wind procedure was 6${\sim}$8 A at 77 K, self field. The maximum field was measured 0.06 T at lop = 5 A, 77 K. The joint resistance due to lap splice of HTS tapes affect badly to operate HTS magnet with persistent current mode, total effective magnet resistance included lap splice was 55 ${\mu}$ ${\omega}$ at 77 K.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.702-706
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• 1996

The King Sejong's Striking water-clock was named for its distictive day and night time announcing system. Its time announcing system generates acoustic and visual signals for the twelve double hour, and combinations of two different acoustic signals for the five night watches, The mechanism of this signal generation system is triggered by a copper ball which is mechanically digitized time keeping signal, and is generated from the water clock. The time announcing system consisted four parts: 1) the mechanical amplifier which changes small copper to heavy steel ball, 2) day time announcing system, 3) night time announcing system, 4) sounding mechanism. The time announcing system of King Seong's Striking Clepsidra is remotely related to the Arabic clock system, however, it does have world-widely distictive mechanisms of its era, such as mechanical amplifier, self-weight rachet mechanism, and resetable mechanical computer etc.

• Proceedings of the Safety Management and Science Conference
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• 2003.11a
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• pp.335-343
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• 2003

In the electrode fabrication of unit cell, it was ascertained that electrochemical characteristics were greatly increased with 90 wt.% of BP-20, 5 wt.% of Super P and 5 wt.% of mixed binder [P(VdF-co-HFP) : PVP =7 : 3] The self-discharge of unit cell showed that diffusion process was controlled by the ion concentration difference of initial electrolyte due to the characteristics of Electric Double Layer Capacitor (EDLC) charged by ion adsorption in the beginning, but this by current leakage through the double-layer at the electrode/electrolyte interface had a minor effect and voltages of curves were remained constant regardless of electrode material. The electrochemical characteristics of 2.3 V/3,000 F grade EDLC were as follows: 0.35 m of DC-ESR (100 A discharge), 0.14 mof AC-ESR (AC amplitude 100 mV), 2.80 Wh/kg (3.73 Wh/L) of energy density and 4.64 kW /kg (6.19 kW/L) of power density. Power output was compatible with electric vehicle applications, uninterrupted power supply and engine starter, in due consideration of Ragone relations.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.128-133
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• 2006

This study is focused on the skill to prevent RIB (Rigid Inflatable Boat) from sinking. For better ability to prevent sinking, single hypalon tube is replaced by double TPU (Thermoplastic Polyurethane) tube that is excellent at frictional wear strength and oil-resisting qualities. High buoyant materials are arranged in empty spaces of ship so that ship's spare buoyancy is increased. And for restoration of stable position of ship, the self-righting system is installed. Aluminium alloy is used for increasing hull strength.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.375-379
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• 2003

In this paper, a novel design of multilayer ceramic-based Transmit/Receive (T/R) switch using Low Temperature Co-fired Ceramic (LTCC) technology have been presented. Compact T/R switch has been designed by transforming quarter-wave transmission line to its lumped equivalent circuit. Especially, high-Q three dimensional inductors with double strip have been proposed and incorporated. The proposed inductor has been modeled by multi-conductor coupled lines. A measured inductor quality factor (Q) of 80 and a Self-Resonance Frequency (SRF) of 6.6 GHz have been demonstrated. The inductor library has been incorporated into the design of WCDMA T/R switch.

• Journal of architectural history
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• v.15 no.4
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• pp.87-105
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• 2006

Dok-Rak-Dang and Hyang-Dan, upper class houses of Chosun Dynasty on the early and mid 16th century, are generally known as specific style houses among traditional residences in Korea. Architectural singularities of these two residences are summarized as double facades, uncertain circulation, self-secluding construction, dilemmatic structure, and rotative circulation that are far from architectonic principle of that time. Characters of Deconstructionist Art, deconstruction of binary oppositions, double session, displacement without reversal, and paradox, are very similar to those of two residences both as a material phenomenon and as a metaphysical idea. Thus, this paper attempt to analyze architectural singularities of Dok-Rak-Dang and Hyang-Dan with the perspective of Deconstructionist Art Theory.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.1
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• pp.95-101
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• 2012

Purpose : The purpose of this study was to investigate the variations in gait parameters according to arm swing use in post stroke hemiparesis. Methods : Sixteen patients participated in this study and walked at self-selected speeds on a Rs-scan systems. The were randomly assigned conditions: self-selected arm swing, constraint arm swing, emphasis arm swing. Results : In the comparison of parameters in each trial, both affected step length, non affected step length, affected stride length, non affected stride length, affected single support time, and non affected single support time were significantly increased and double support time was significantly decrease in emphasis arm swing when compared with both self-selected arm swing and constraint arm swing(p<.05). However, Asymmetrical ratio was significantly increased in both emphasis arm swing and self-selected arm swing when compared constraint arm swing(p<.05). Conclusion : Therefore, In this study, gait rehabilitation of patients with hemiplegia depending on what you need to apply the arm swing is considered.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.6
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• pp.604-608
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• 2008

The TFT-LCD image allows non-uniform illumination variation and that is one of main difficulties of finding defect region. The SQI (self quotient image) has the HPF (high pass filter) shape and is used to reduce low frequency-lightness component. In this paper, we proposed the TFT-LCD defect-enhancement algorithm using characteristics of the SQI, that is the SQI has low-frequency flattening effect and maintains local variation. The proposed method has superior flattening effect and defect-enhancement effect compared with previous the TFT-LCD image preprocessing.