• Journal of Korean Association for Spatial Structures
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• v.7 no.2 s.24
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• pp.35-44
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• 2007

The characteristics of elasto-plastic responses of a gymnasium building which is a steel braced frame with membrane roof is discussed as a basic research on the performance based seismic design of large span structures, in this paper. Under the strong earthquake motions, the formation of plastic hinges on braces attached by the bottom frame make reduce down the stresses and displacements of upper structures, and vertical acceleration of the membrane is tend to increase but maximum response of strain and corresponding stresses are tend to be reduced.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.369-375
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• 2003

Xiaoshuan Zaizao Wan (XZW) has been used in China to improve hemiplegia, deviation of eye and mouth, and dysphasia due to cerebral thrombosis. To characterize pharmacological actions of XZW, we evaluated its effects on neuronal cell damage induced in primary cultured rat cortical cells by various oxidative insults, glutamate or N-methyl-D-aspartate (NMDA), and $\beta$-amyloid fragment ($A_{\beta(25-35)}$). XZW was found to inhibit the oxidative neuronal damage induced by $H_2O_2$, xanthine/xanthine oxidase, or $Fe^{2+}$/ascorbic acid. It also attenuated the excitotoxic damage induced by glutamate or NMDA. The NMDA-induced neurotoxicity was more effectively inhibited than the glutamate-induced toxicity. In addition, we found that XZW protected neurons against the $A_{\beta(25-35)}$-induced toxicity. Moreover; XZW exhibited dramatic inhibition of lipid peroxidation in rat brain homogenates and mild 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Taken together; these results demonstrate that XZW exerts neuroprotective effects against oxidative, excitotoxic, or $A_{\beta(25-35)}$-induced neuronal damage. These findings may provide pharmacological basis for its clinical usage treating the sequelae caused by cerebral thrombosis. Furthermore, XZW may exert beneficial effects on Alzheimer's disease and other oxidative stress-related neurodegenerative disorders.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.74-80
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• 1997

In this paper, we deal with the I -t characteristic of low voltage distribution fuse (line fuse). That fuse element has two parts;One is low temperature melting element(LTME) to put up with over current and the other is high temperature melting element (HTME) which put up with large current. Melting charateristic of fuse is determined by L TME and HTME. So we verified their properties of fuse design, mathematically, by simulating the thermal and electric characteristics of each other. We simulated the I-t characteristic of line fuse by using the numerical method;Finite Element Method(FEM). Then, we could acquire very similar result at the HTME and L TME area when compared the simlation result with experimental one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.547-550
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• 2005

This treatise studies and developed flash memory drive of ATA bus that use flash memory which is employment amount memory semiconductor to improve problem of hard-disk that is existing ATA bus. While general hard-disk is sensitive external impact or shock, but flash memory drive do save chapter as well as is strong in external impact using semiconductor memory element that disk is not low electric power, light weight possible . Practical use is expected do save chapter for embedded system or black box for vehicles, soldiers hereafter therefore.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.226-231
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• 2009

Purpose: Bilateral traumatic locked posterior dislocations of the shoulder are very rare and there has been no report on the operative treatment for this injury in the Korean medical literature. Materials and Methods: We present here a case of bilateral locked posterior dislocations of the shoulders after trauma and this was successfully treated with open reduction and lesser tuberosity transfer on the right shoulder and subscapularis tendon transfer on the left shoulder. Results and Conclusion: Twenty-four months later, the clinical and radiologic results were excellent.

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.95-100
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• 2008

In the design of ground improvement using band-shaped prefabricated vertical drains (PVD), it is required to determine a reasonable equivalent circle of PVDs. In this paper, a series of numerical analyses on soft clay ground improved by PVD were carried out in order to investigate the resonable equivalent circle of PVD considering consolidation behavior of improved soft clay ground by PVD. The applicability of numerical analyses, in which an elasto-viscoplastic three-dimensional consolidation finite element method was applied, could be confirmed comparing with consolidation behavior simulated at the laboratory. And, through the results of the numerical analyses, consolidation behaviors of soft clay ground with elapsed time were elucidated, together with the equivalent circle of PVD considering consolidation behaviors.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.877-887
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• 1994

Cu-Ni-Si-P alloys have been studied in order to develop connector material which has a favorable combination of strength, electrical conductivity, elastic limit, thermal softening resistence and bend formability. Three kinds of trial alloys with various nickel and silicon content were melted and cast, hot rolled at about $900^{\circ}C$ and cold rolled. Mechanical properties and electrical conductivities of these alloys annealed at $450^{\circ}C$, $500^{\circ}C$ and $550^{\circ}C$ were investigated. An alloy with the composition of Cu-2.7%Ni-0.53%Si-O.O29%P, which shows a favorable combination of high strength and high electrical conductivity, has been developed. Various characteristics of the alloy 1 connector material were evaluated and compared with phospher bronze(C521OR-H) and brass(C26OOR-EH) connector material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.158-158
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• 2009

기계적 에너지를 전기적 에너지로 변환하는 에너지 변환소자인 압전 세라믹스는 액추에이터, 변압기, 초음파모터 및 각종 센서로 응용되고 있으며, 그 응용분야는 크게 증가하고 있다. 최근에는 이러한 압전 소자를 앞으로 도래하는 ubiquitous, 무선 모바일 시대의 휴대용 전자제품, robotics 등의 분야에 적용하기 위하여 소형화 및 경량화를 구현하고자 다양한 연구가 진행되고 있다. 본 연구에서는 압전 특성이 우수한 PNN-PMN-PZT 삼원계 세라믹을 이용하여 압전 트랜스포머를 제작하고 전기적 특성을 평가하였다. 압전트랜스포머는 전왜-압전효과를 이용한 소전력용 고전압발생소자로서 종래의 권선형 트랜스포머에 비교해서 소형, 경량이면서 승압비가 높고 구조가 간단하므로 직류 고전압전원에 응용되고 있다. 압전트랜스의 이론적인 고찰은 Rosen 이후로 많은 연구자들에 의해서 보고되었다. 그런데 압전세라믹트랜스는 공진 시 강력한 에너지변환을 하기 때문에 재료의 물리적 특성이 매우 중요함에도 불구하고, 이러한 물리적 특성에 관한 연구는 거의 없었다. 따라서 본 연구에서는 물리적 특성과 전기적 특성의 상호 연관성을 고찰하고자 하였다. 압전트랜스용 재료는 전기기계결합계수($k_p$)와 기계적품질계수(Qm)가 높아야 한다. 전기기계결합계수를 높이기 위해서는 상경계 조성의 Pb(Zr,Ti)$O_3$[PZT]계 세라믹스가 가장 우수하다. 본 연구에서는 기계적 품질계수를 향상시키기 위해서 $Pb(Nn_{1/3}Nb_{2/3})_{0.06+x}(Mn_{1/3}Nb_{2/3})_{0.065-x}(Zr_{0.48}Ti_{0.52})_{0.875}0_3$계의 조성을 설계하여 압전특성을 평가하고 미세구조를 분석하였다. 또한 압전트랜스를 제작하여 입출력의 승압비 및 주파수 특성 등도 평가하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1614-1616
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• 2011

지중송전라인에서 전압등급의 상승은 선로손실을 줄이면서 밀집된 전력수요에 대응하거나 특별히 고전압 수요를 맞추기 위한 것으로 이것은 XLPE Cable의 제조기술이 향상되면서 지속적으로 진행되어온 초고압송전계통의 일반적 추세이다. 이러한 경향으로 해외에서는 케이블 도체의 송전용량을 증대시킬 수 있는 방법으로 케이블 도체에 에나멜 코팅을 하여 집합을 한다. 그러므로써 기존 케이블에서 발생되는 표피현상 및 근접효과에 의한 AC 저항 요소를 줄여 요구하는 전류용량을 기존 비소선절연 케이블에 비해 더 많이 송전할 수 있다. 하지만, 소선절연 케이블이 전류 용량을 증대 시킬 수 있는 장점은 있으나 접속재의 경우 도체의 에나멜 코팅을 제거해야 하는 문제점이 있다. 당사는 에나멜 코팅을 제거하는 방법을 개발 완료함으로써 본 접속재의 개발을 앞당길 수 있었다. 당사는 쿠웨이트 400kV MEW/C/3931 Project에 400kV XLPE 1C${\times}$2500SQ 소선절연 초고압송전라인을 적용하였는데 본고에서는 여기에 적용된 400kV XLPE 1C${\times}$25000SQ 소전절연 케이블 부속재의 신뢰성을 높이기 위한 설계방법, 시험 및 시공에 대하여 요약하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.113-120
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• 2002

This paper describes characteristics of transient voltage waveforms caused by human electrostatic discharges(ESDs). For purpose of achieving the statistics on the meaningful amplitude and initial slope for transient ESD voltage waveforms, transient voltages due to human ESDs in various conditions were observed. A voltage measuring system with a wide bandwidth from DC to 400[MHz] was employed. ESD voltage waveforms are approximately the same as ESD current waveforms. Also the simulated results, which are calculated by the reposed equivalent circuit, are closely similar to the measured voltage waveforms. ESD voltage waveforms are strongly dependent on the approach speed and material of intruder, a fast approach causes ESD voltage waveform with a steep rise time than for a slow approach. The voltage waveforms from dialect finger ESDs have a relatively long rise time of 10∼30[ns], but their peaks are low. On the other side ESD voltage waveforms causer by screwdriver with insulating handle have a steep slope with a very short, less than 1[ns] rise time, but their initial spikes are extremely high The obtained results in this work would be applied to solve ESD problems for low voltage and small current electronic devices.