• 한국전기전자재료학회논문지
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• 제19권2호
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• pp.158-161
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• 2006

The purpose of this research is to establish the crosstalk characteristic of mm-wave Coplanar structure. The components in mm-wave CPW are classified to transmission devices, EM devices, and quasi - TEM devices. After design of these devices, we analyzed these CPW s electromagnetically using FDTD method, and suggested the corsstalk characteristic of mm-wave CPW. In oder to realize a CPW module up to 30 GHz-100 GHz band, we research on a technology of 3-dimensional mm-wave CPW, and GaAs substrate with ohmic lossy layer. As a result this research, we suggested the optimum crosstalk characteristic of mm-wave CPW, and improved the crosstalk quality of mm-wave CPW.

• Journal of Advanced Marine Engineering and Technology
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• 제30권4호
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• pp.520-526
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• 2006

Wave Energy is a derivative of the solar energy input to the earth, which is accumulated on open water surfaces by the action of the winds Waves are disturbances in the water surface. This paper is interested primarily in progressive waves, which carry energy from one place to another Waves are irregular in size and frequency. Moreover the surface of the sea is one of the most hostile environments for engineering structures and materials. The idea of harnessing the tremendous power of the ocean's waves is not new. Hundreds of wave energy conversion techniques have been suggested over the last two centuries. Although many WECS (Wave Energy Conversion Systems) have been invented, only a few systems have been tested and evaluated. This paper describes the characteristic of WES (Wave Energy System) in terms of, devices, resource and potential, etc.. Finally, this paper provides a summary of general and specific conclusions and recommendations concerning WECS potential in Korea.

• 패션비즈니스
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• 제12권6호
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• pp.11-22
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• 2008

The goal of this study is to provide beauticians with the fundamental material to use effectively heat permanent wave in beauty industry as well as their customer's satisfaction. It carried out an experiment with damaged hair of a woman in her late twenties to investigate the change of physical and morphological characteristics by its water content when performing heat permanent wave. After spreading 0g, 1g, 2g, 3g, and 4g of water on damaged hair respectively, heat permanent wave was treated and the change of hair was observed. The change of physical characteristic was compared through permanent wave form of hair, tensile strength and elongation. The change of morphological characteristic was observed through Scanning Electron Microscope(SEM) and Transmission Electron Microscope(TEM). The result of experiment on the physical specificity revealed that permanent wave form was the most ideal when the water content was 2g, also 3g. Though the materials with much moisture content formed the results were not satisfied. The material with 0g of water content didn't make the wave. In terms of tensile strength and elongation, tensile strength was generally reduced as per the damaged degree of hair. On the contrary, elongation was increased. It observed the changes of morphological characteristic that the damage on hair cuticle was deepen, as its moisture content was decreased, and cuticle's surface was worn away. The observation of fine structure on hair section by transmission electronic microscope also certainly showed the result that damaged hair having experience with chemical treatment had got much damaged to hair cuticle as well as hair cortex. Generally chemical treatment makes hair damaged. Under consideration of this aspect, the ultimate goal of this thesis is to minimize the damage of hair caused by chemical treatment and get the satisfaction on the hair style. According to the result of experiment, the damaged hair whose moisture content was 3g showed the best permanent wave form.

• 한국전자파학회논문지
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• 제20권6호
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• pp.509-515
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• 2009

최근 급성장하고 있는 정보처리 속도의 고속화와 IC 기술의 고집적화에 따른 소형화와 모바일화는 대부분 GHz 대의 높은 주파수를 이용하며, 인접 소자 또는 배선 간의 상호 간섭, 배선을 통한 노이즈의 전도 및 방사를 유발하여 EMC(Electromagnetic Compatibility) 대책 기술의 주요 과제로 대두되고 있다. 이러한 문제점을 해결하기 위해 전파흡수체 및 차폐재의 개발이 활발히 진행 중이며, 이를 적절한 위치에 부착시킴으로써 PCB상에서의 전자파 노이즈 방사를 감소시킬 수 있다. 따라서 본 논문에서는 EMC 대책 기술 중 전파흡수체를 이용한 PCB 기판상의 불요 전자파 노이즈 억제용 전파흡수체의 특성 파악을 위하여 마이크로스트립 라인법을 이용하여 전파흡수체를 측정하여 재료 정수의 복소비 투자율의 변화에 따른 노이즈 억제 효과의 변화를 비교 분석하였다. 우선 자성 재료인 Amprphous와 Sendust를 지지재인 CPE를 이용하여 조성비별 샘플을 제작하여 측정하였다. 자성 재료의 투자율의 값은 높은 허수부의 값을 가지며, 손실 탄젠트의 값이 큰 재료일수록 우수한 노이즈 특성이 나타남을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1416_1417
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• 2009

This paper shows the characteristic of wave tail according to inductance values in 10/$350{\mu}s$ impulse circuit with crowbar switch. The PSpice was used to simulate the 10/$350{\mu}s$ current waveform and lightning current impulse generator was used to generate real current waveform. As a capacitor of condenser bank increases, a virtual front time increases and a time to half-value decreases. To get a perfect 10/$350{\mu}s$ current waveform, we should consider the combination of circuit values of the inductance, capacitance, time difference between trigger pulses and charged voltage of capacitor bank.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2632-2634
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• 2011

In the Structural Health Monitoring field, the piezoelectric elements are bonded the surface of the structures for generating the guided wave. For this reason, the structures become two-layer beam. It is very important to know precisely the dynamic characteristic of structures and also predict precisely the wave propagation in structures. Because wave propagation is very useful to analysis the dynamic characteristic of structures. In this paper, the governing equations of motion are derived from Hamilton's principle by applying the Timoshenko beam theory and Mindlin-Herrmann rod theory at the first. and then the wave propagations in a composite beams with a surface-bonded piezoelectric are examined.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2003년도 춘계공동학술대회논문집
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• pp.141-146
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• 2003

저질의 부유 현상이 일련의 쇄파라고 하는 파동 현상에 어떠한 형태로 연동하는가를 면밀히 조사하기 위하여 현지해안의 쇄파대내에 주 관측지점을 설치하고 부유사 농도와 유속, 수위변동 등의 관련 파랑 제원을 계측하였다. 분석을 위해 수위변동, 유속변동치의 부유사농도에 대한 상관관계를 조사하였으며, 상관이 탁월한 주기대에 대한 ensemble 평균 분석으로 유속 및 수위변동의 위상에 따른 부유사 농도의 변화와의 관계를 명백히 하여 다음의 결론을 얻었다. 1) 부유사의 농도 변동은 유속 및 수위변동의 에너지가 가장 큰 장주기 성분(100s)에 있서 상관이 높았으며, 2) 또한, 1차mode의 장주기중복파의 유속 성분이 해안으로 향하여 가속하는 위상 즉, 수면 경사가 상대적으로 해안선측보다 외해측이 높은 위상에서 부유사 농도가 가장 높아짐을 명백히 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.745-747
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• 2001

This paper deals with the dynamic characteristics of flat core LOA. The LOA system was represented by the voltage equation of coil and the mechanical equation of motion. Also, driving system was simply composed voltage source inverter and generates square-wave. It is measured that dynamic characteristic vary as square-wave.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1237-1240
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• 2007

Tire noise is a major noise source at high speeds. One of the noise source is controlled by pattern and structure. Pattern noise is effected by the shape of tread. And the bending stiffness of tire is influenced to the resonance of tire‘s belt. But in high frequency region, FEA is not appropriated with application. So this paper discusses about wave propagation of tire. There has been much effort to verify the flexural wave velocity with structure design specification.

• 한국전자파학회논문지
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• 제10권5호
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• pp.694-700
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• 1999

본 논문에서는 마이크로스트립 구조에서의 접지변에 식각된 패턴을 갖는 PBG(Photonic Bandgap) 구조의 S Slow-wave 특성을 이용한 전력 분배기 설계에 대해 연구하였다. 또한 제시된 PBG 구조는 전송선로의 특성 임피던스를 변화시켜 기존 구조에 비해 선로의 폭을 넓게 할 수 있고 Slow-wave 특성에 의해 소자의 크기가 감소된 Wilkinson 3 dB 전력 분배기를 설계하였다. 제시된 임의의 PBG 구조를 산란 파라미터로부터 전송선로의 특성 임피던스와 전기적 길이를 추출하여 응 용하는 방법을 제시하였고 같은 모양의 결손(defect)을 추가함으로써 그 영향을 고찰하였다. 제시된 방법으로 구현된 전력분배기의 측정 결과는 시율레이션 결과와 잘 일치함을 보였다.