• 전기의세계
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• 제30권6호
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• pp.357-365
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• 1981

When electronegative gas SF$_{6}$ is dissolved and charged with insulating oil, the effect caused in the process by electronegative characteristic is studied and also the pressure effect caused by electronegative SF$_{6}$ acting on the liquid-level is examined respectively. When inert gas Ar is used to find a pressure effect acting on the liquid-level, its effect on dielectric strength is considered in the experiment. With three kinds of impulse voltage different in the duration of wave front and wave tail, a brief experiment if carried out ot see the effects on the dielectric breakdown characteristic as the wave is changing; either if I$_{2}$ and SF$_{6}$ are added to the insulating oil, or if the oil pressure is increased by Ar the dielectric strength becomes great and the longer the duration of wave front is, the greater the increase of the breakdown voltage, because I$_{2}$ added by a small quantity brings about some hirderance in the formation of gas phase. Likewise, the greater the changed pressure is, the greater the incerase of the breakdown voltage. When SF$_{6}$ is charged, the electronegative characteristic is prevailing at the time of low balanced pressure, and the pressure effect at the time of high balanced pressure.ressure.

• 대한전기학회논문지
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• 제34권4호
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• pp.144-152
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• 1985

This paper temperature gradient thermally stimulated surface potentian (TG-TSSP) in measurements are applied to the study of the polarity of trapped and ionic carriers in cross-linked polyethylene (XLPE) filsm. In the thermally stimulated current in uniform temperature (TSC) of XLPE five peaks appear as indicated of the A B C D and E. In this paper A (at about -120$^{\circ}C$) D (at about 70$^{\circ}C$) and E (at about 110$^{\circ}C$) peaks are investigated. A peak is due to the biassing voltage and biassing temperature. Appear in to the glass transition temperature territory and caused in to the polarization of dipole. D peak is due to the depolarization of ionic space charge and E peak due to the detrapping of carriers injected from the electrodes. TG-TSSP and TSSP are measured to study the polarity of ionic carrier (D peak). In the unsatureated region of ionic space charge polarization, TG-TSSP is lower than TSSP during the initial stage of heating. Result of the experiment for E peak, TG-TSSP is higher than TSSP during the initial stage of heating and these results do not depend on the polarity of biassing voltage, and E peak is concerned with positive carriers (Holes).

• 한국자동차공학회논문집
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• 제6권6호
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• pp.210-217
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• 1998

This paper describes the method for detection of the misfired cylinder using the pressure fluctuations occurred in the exhaust system on an MPI gasoline engine. If misfire is occurred in the cylinder of the gasoline engine, the power of engine gets lost, the fuel consumption and the exhaust emission are increased and the vibration is caused by unsteady torque. Therefore early detection and correction of misfire play a very important role in the proper performance and the exhaust emission. This paper suggests method of misfire detection which affect engine performance. The method is a comparison of average pressure index during the displacement period. Experimental results showed that the method using the pressure fluctuations in the exhaust system is proven to be effective in the detection of misfire on gasoline engine regardless loads and revolutions of the engine. In addition, this method, using the pressure fluctuations in exhaust system is easier than other methods and is not a need of additional reconstruction of engine.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.58-64
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• 2006

Homogeneous charge compression ignition(HCCI) combustion is an advanced technique for reducing the hazardous nitrogen oxide(NOx) and particulate matter(PM) in a diesel engine. NOx could be reduced by achieving lean homogeneous mixture resulting in combustion temperature. PM could be also reduced by eliminating fuel-rich zones which exist in conventional diesel combustion. However previous researches have reported that power-output of HCCI engine is limited by the high intensive knock and misfiring. In an attempt to extend the upper load limit for HCCI operation, supercharging in combination with Exhaust Gas Recirculation(EGR) has been applied: supercharging to increase the power density and EGR to control the combustion phase. The test was performed in a single cylinder engine operated at 1200 rpm. Boost pressures of 1.1 and 1.2 bar were applied. High EGR rates up to 45% were supplied. Most of fuel was injected at early timing to make homogeneous mixture. Small amount of fuel injection was followed near TDC to assist ignition. Results showed increasing boost pressure resulted in much higher power-output. Optimal EGR rate influenced by longer ignition delay and charge dilution simultaneously was observed.

• 한국결정성장학회지
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• 제9권1호
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• pp.39-42
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• 1999

N-도핑된 3C-SiC (N-SiC(3C))을 화학기상증착(CVD)으로 $1250^{\circ}C$에서 Si(111) 기판 위에 tetramethylsilane(TMS)를 열분해하여 성장하였다. 수송가스는 $H_{2}$이었고, N-SiC(3C) 에피층은 CVD로 성장되는 동안 $NH_{3}$에 의하여 n-형으로 도핑되었다. N-SiC(3C)의 물리적 특성은 적외선 분광(FTIR), X-선 회절(XRD), 라만 스펙트럼(Raman spectrum), 단면 투과전자영상(XTEM), Hall 측정 및 p/n 다이오드의 전압-진압(I-V) 특성에 의하여 조사되었다. N-도핑된 SiC(3C) 에피층의 전도형은 n-형이었고, 전도형은 $NH_{3}$를 사용한 N-dopant에 의하여 저온에서 잘 조절될 수 있다.

• 한국결정성장학회지
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• 제9권2호
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• pp.212-216
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• 1999

SiC(3C) 광다이오드는 p-형 Si 위에 tetramethylsilane (TMS)를 열분해아여 화학기상증착법으로 성장된 SiC(3C) 에피층을 성장하여 제작되었다. SiC(3C)의 전기적 특성은 홀 측정(Hall measurement) 및 전류-전압(I-V) 특성으로 조사되었다. SiC(3C) 에피층의 전도형은 n-형이었다. 저항성 접촉은 마스크 (shadow-mask)를 통해서 Al을 열증착하여 형성하였다. SiC(3C)광다이오드의 광학적 이득(photovoltaic detection)를 해석하기 위하여 SiC(3C) 에피층의 Spectral response (SR)를 전기적 변수(electrical parameter) 및 광다이오드의 기하학적 구조(geometric structure)를 고려하여 계산하였다. 적절히 선정된 변수들로부터 계산된 SR의 최대값은 550 nm에서 약 0.75이었고, 파장영역 400~600 nm 사이에서 청색 및 근자외선 광검지기로서 매우 유용하다.

• 한국조명전기설비학회지:조명전기설비
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• 제11권3호
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• pp.80-87
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• 1997

Polyimide LB막 의 시료 와 {{{{Al/{Al}_{2}{O}_{3}/PI(nL)/Au}}}} 에 대해 전압의 온도특성 실험에서 상부전극과 하부전극간에 일함수차를 발견하였다. Polyimide LB\ulcorner은 Z형으로 누적하거나 , imide화하면 막에 분극이 발생하지 않았다. 또 {{{{{C}_{15} TCNQ}}}} LB 막 시료{{{{Al/{Al}_{2}{O}_{3}/{C}_{15} TCNQ(10L)/Al}}}} 은 상, 하부 전극이 같아 일차함수가 없었으며 막에 분극이 발생하였다. LB 초박막 MIM 소자를 시료로 하여 실험한 결과 수백 mV 이상의 직류가 발생하였으므로 전기.전자 및 정보통신 분야의 산업용 전원으로 이용할 수 있다고 생각한다.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.1-7
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• 2007

The effect of injector geometries including the injection angle and number of nozzle holes on homogeneous charge compression ignition (HCCI) engine combustion has been investigated in an automotive-size single-cylinder diesel engine. The HCCI engine has advantages of simultaneous reduction of PM and NOx emissions by achieving the spatially homogenous distribution of diesel fuel and air mixture, which results in no fuel-rich zones and low combustion temperature. To make homogeneous mixture in a direct-injection diesel engine, the fuel is injected at early timing. The early injection guarantees long ignition delay period resulting in long mixing period to form a homogeneous mixture. The wall-impingement of the diesel spray is a serious problem in this type of application. The impingement occurs due to the low in-cylinder density and temperature as the spray penetrates too deep into the combustion chamber. A hole-type injector (5 holes) with smaller angle ($100^{\circ}$) than the conventional one ($150^{\circ}$) was applied to resolve this problem. The multi-hole injector (14 holes) was also tested to maximize the atomization of diesel fuel. The macroscopic spray structure was visualized in a spray chamber, and the spray penetration was analyzed. Moreover, the effect of injector geometries on the power output and exhaust gases was tested in a single-cylinder diesel engine. Results showed that the small injection angle minimizes the wall-impingement of diesel fuel that results in high power output and low PM emission. The multi-hole injector could not decrease the spray penetration at low in-cylinder pressure and temperature, but still showed the advantages in atomization and premixing.

• 한국잠사곤충학회지
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• 제46권1호
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• pp.12-17
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• 2004

잠상 123호를 수원, 공주, 전주와 장성 4개 지역에서 수행한 지역적응시험 결과, 수량성이 높고 엽질 등이 우수하여 2001년 수일뽕으로 명명하여 장려품종으로 지정하였으며 그 주요 특성은 다음과 같다. 1. 청일뽕 자연교잡 실생에 콜히친 처리하여 얻어진 4개체 411호와 국상 21호를 교배하여 얻어진 3배체로 백상형 (Morus alba L.)에 속하는 암나무이다. 2. 수형은 직립성이고 개량뽕에 비하여 가지수는 큰 차이가 없으며, 평균가지 길이와 마디사이길이는 짧고 가지 굵기는 굵다. 3. 발아기는 중뽕이며, 잎의 크기는 대형으로 잎두께는 약간 두꺼우며 타원형과 3-5열엽이 섞여 존재하지만 5열엽이 많다. 3. 뽕 수량은 개량뽕보다 20% 많으며, 사료가치는 청운뽕과 같은 수준으로 비교적 우량하다. 4. 뽕나무 오갈병 저항성은 개량뽕보다 약간 약하나, 눈마름병, 줄기마름병 및 축엽세균병은 개량뽕과 비슷한 수준이다. 5. 춘추잠기 겸용 큰누에용 뽕으로 동해상습지를 제외한 전국에 재배할 수 있다.

• 보존과학회지
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• 제10권1호
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• pp.1-9
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• 2001

본 연구의 목적은 전남 고흥 능가사 대웅전과 천왕문에서 발굴된 종이와 섬유의 해부학적 특성과 미량 화학성분을 광학현미경, 화상해석, 주사전자현미경(SEM-EDS)으로 분석하는 것이다. 모든 종이는 닥나무로 식별되었다. 인피섬유에서 분리된 투명막의 존재가 특징적이었다. 대웅전 벽에 붙여 있는 종이가 가장 손상이 심하였으며 천왕문에서 발굴된 책의 종이 세포는 비교적 보존 상태가 양호하였다. 천왕문의 동방지국상 아래에서 발굴된 섬유는 매우 좁은 세포폭을 갖는 실크이었다. SEM-EDS 분석에서 높은 실리카 함량이 발견되었다. 종이 내에서 발견된 칼슘, 철, 염소, 그 밖의 미량원소 분석 결과를 연대, 생산지 및 보존처리와 관련하여 고찰하였다.