• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 2nd Korea-Japan Advanceed Semiconductor Packaging Technology Seminar
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• pp.195-201
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• 2000

Current Status: Good Electrical performance for high speed device, Solder joint reliability-Passed 1600 cycles for 4M SRAM(3.27mm DNP),-Passed 400 cycles for large die(5.71 mm DNP), Future Plan: Improving Board Level Reliability for large die size, Lead free solder evaluation.

• 한국해양학회지:바다
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• 제9권3호
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• pp.130-136
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• 2004

In September 2003 wind-measuring drifters were air-deployed in front of the projected path of Hurricane Fabian from an altitude between 300 m and 400 m. Eight drifters transmitted wind, air pressure and SST data through ARGOS and three drifters were within 35 km of the hurricane center. Measurements of the air pressure in the eye of the hurricane by dropsondes, suggested the air pressure at the eye was between 939 hPa and 944 hPa. The lowest pressure measured by a Minimet was 943 hPa at 33 km from the hurricane center. Fabian cooled the SST at its center from $28.9^{\circ}C$ to $26.8^{\circ}C$. After the passage of Fabian, SST warmed to between $27.5^{\circ}C$ and $28.5^{\circ}C$ in 7 days.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.944-947
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• 2003

We report efficient white organic electroluminescent devices consisting of a blue-emitting layer of 9,10-bis[(2",7"-di-t-butyl)-9',9"-spirobifluorenyl]anthracene (TBSA) and a red-emitting layer of 4-dicyanomethylene-2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[i,j]quinolizin-8-yl)vinyl]-4H-pyran) (DCM2) doped into 4,4'bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (${\alpha}-NPD$). The device shows the CIE coordinates of (0.32, 0.37). The external quantum efficiency is about 3.4 % and the luminous efficiency is about 3.9 lm/W at luminance of 100 $cd/m^{2}$. The maximum luminance is about 45,400 $cd/m^{2}$ at 11.5 V.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2130-2132
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• 1998

With the increasing demands for clean environment, development of air cleaning systems has been received increasing attention. EP is usually used for air cleaning in the coal power plant. One of the key technology in the EP is high voltage pulse power supply, which affects the performance of the overall system. In this study, high voltage micro pulse power supply for the EP is developed for a 500MW coal power plant. The power supply has a dc source and a pulse one. The ratings of the dc and pulse source are 60kV, 800mA and 70kV, 400mA respectively.

• 소성∙가공
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• 제31권3호
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• pp.117-123
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• 2022

In this study, a commercial AZ61 magnesium alloy is extruded at 300 ℃ and 400 ℃ and the microstructures, mechanical properties, and high-cycle fatigue properties of the extruded materials are investigated. Both extruded materials have a fully recrystallized microstructure with no Mg₁₇Al₁₂ precipitates. The average grain size and maximum basal texture intensity of the extruded material increase with increasing extrusion temperature. The material extruded at 400 ℃ (AZ61-400) has higher tensile yield strength and lower compressive yield strength than the material extruded at 300 ℃ (AZ61-300) because of the stronger basal texture of the former. Because of coarser grain size, the tensile elongation of AZ61-400 is lower than that of AZ61-300. Despite the differences in microstructures and tensile/compressive properties, the two extruded materials have the same fatigue strength of 110 MPa. This is because the finer grain size of AZ61-300 causes an increase in fatigue strength, but its weaker texture causes a decrease in fatigue strength. In both extruded materials, fatigue cracks initiate at the surface of fatigue specimens at all stress amplitudes tested.

• 한국토양비료학회지
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• 제45권6호
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• pp.897-899
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• 2012

본 연구는 대구획으로 경지정리된 후 5년차인 1 ha의 논 및 4대강 주변의 리모델링 농경지 밭을 대상으로 하여 그에 따른 화학적 특성들을 조사하여 그 포장내의 공간변이를 파악하고 각 성분들간의 상호관련성을 비교하고자 수행되었다. 5년차인 1 ha의 논에서 5 m 간격으로 총 $20{\times}20=400$점의 시료를 채취하여 분석에 이용하였으며 매립적토형 인위토양은 10 m 간격으로 $6{\times}9=54$점의 시료를 채취하였다. 화학성분 중 pH, 유효인산, 유기물함량 등을 분석하여 그 결과를 해석하였다. pH는 구미지역에서 7.1로 높게 나타났으며, 유효인산 및 유기물함량의 경우 모두 변이계수가 높았으며 이는 한 포장 내에서도 상당히 불균일하다고 볼 수 있었다. 왜도(skewness)와 첨도(kurtosis) 등은 그 절대값으로 볼 때 거의 정규분포에 가까운 형태로 보이고 있다. 안성의 논에서는 유효인산 (72.8) ${\fallingdotseq}$ pH(73.8) < 유기물(159.3)의 순, 구미의 밭에서는 유기물(6.5) < 유효인산(33.5) < pH(46.6)의 순으로 Range값이 높아졌다. 이는 상대적으로 5년된 토양에서보다 0년차의 토양에서 시료채취를 많이 해야 한다는 의미로 해석할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.139-142
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• 2000

Influence of frequency and duty ratio on electro-optical characteristics are experimentally investigated in surface AC plasma display panels(AC-PDPs) by using the VDS(Versitile Driving Simulator)., in which electrode gap and width are 100 ${\mu}m$ and 260 ${\mu}m$, respectively. The filling gas is Ne-Xe gas mixture, and total pressure 400 Torr. It is found that the response time gets to be fast from 450 ns to 150 ns as pulse-off time of the sustain pulse decreases from 2 ${\mu}s$ to 0.2 ${\mu}s$. Also it is found that the IR(Infra Red) intensity and the luminous decreases as pulse-off time of the sustain pulse increases from 0.2 ${\mu}s$ to 2 ${\mu}s$.

• 한국식품영양과학회지
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• 제29권1호
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• pp.49-56
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• 2000

The 2-O-$\alpha$-D-glucopyranosyl L-ascorbic acid (AA-2G) which was enzymatically glucosylated with the cyclodextrin glucanotransferase (CGTase) [EC 2.4.1.19] from Bacillus sp. JK-43 has been reported previously. The presnet experiments examined the optimal conditons for the productio of AA-2G from AA and soluble starch, and characterized the properties of the CGTase from Bacillus sp. JK-43. The reaction mixture for the maximal production of AA-2G was followings; 12% total substrate concentration, 1,400 usits/mL of CGTase and a mixing ratio of 2 : 3(g or AA : g of soluble starch). Under this condition, 1.76mM of AA-2G, which corresponded to 2.53% yield based on AA, was produced after incubation for 24hrs at 45$^{\circ}C$ (pH 5.5). The optimum pH and temperature for the CGTase activity were 6.0 and 45$^{\circ}C$, respectively. The enzyme was stable at pH 5.5 to 9.5, and at temperature up to 5$0^{\circ}C$. The thermostability of the enzyme could be enhanced up to 6$0^{\circ}C$ by the addition of 30mM CaCl2.

• 한국산림과학회지
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• 제109권1호
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• pp.1-22
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• 2020

소백산국립공원 삼가지구 관속식물의 고도별 수직분포 및 분포변화를 파악하기 위해 삼가탐방지원센터(400 m)에서 정상(1,439 m)까지 해발 100 m 단위로 등분하여 11개 구간에 대한 식물목록을 작성하였다. 현지조사를 실시한 결과 92과 235속 332종 3아종 37변종 3품종 총 375분류군이 출현하였다. 구간별 식물 종다양성 패턴을 분석한 결과, 고도가 증가함에 따라 점차 종다양성이 감소하다가 특정구간에서 증가하는 역단봉형 패턴이 나타났다. 고도에 따른 종 분포패턴과 치환성 양이온 Ca²⁺, Mg²⁺ 와 토양 pH, 유효인산, 온량지수, 조사면적 등의 환경요인이 양의 상관관계를 보였고 경사, 토양 수분, 치환성 양이온 Na²⁺이 음의 상관관계를 보였다. DCA 분석 기법을 이용하여 구간별 식분의 분포를 분석한 결과 I, II축 상에서 2개의 그룹으로 구분되었다. 구간별 식분의 배치는 400~500 m 구간부터 1400~1500 m 구간까지 순차적으로 배열되었다. 이러한 식분의 배치에 영향을 미치는 환경요인은 토양 수분, pH, K2⁺, Na²⁺, 유효인산, 경사도 등 토양 및 지형적 요인으로 나타났다. 생물다양성 보전, 지속가능한 이용에 있어서 본 연구 결과는 중요한 기초자료로서 역할을 할 것으로 기대되며, 식물종들의 생태·환경적 특징과, 분포범위를 파악하기 위해서는 지속적인 모니터링과 함께 관련 연구들을 지속적으로 발전시켜야 할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2135-2137
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• 2005

This paper describes the features of electric and magnetic fields produced by lightning discharges. The measuring system consists of fast electric field sensor, crossed-loop magnetic field sensors, signal processing circuit, A/D converter and data acquisition equipment with a 12bit resolution and 10[MS/s] sampling rate. The frequency bandwidth and responsitivity of the electric field measuring system were 40[Hz]${\sim}$2.6 [MHz] and 2.08 (V/m/mV) and those of the magnetic field measuring system were 400[Hz]${\sim}$1[MHz] and 2.78[nT/mV], respectively. The electric and magnetic fields produced by lightning discharges were observed, and the features and parameters of the waveforms were analyzed.