• 대한전자공학회논문지SD
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• 제42권3호
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• pp.9-16
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• 2005

[ $Si_{1-x}Ge_x$ ] 위의 Si 반전층에서의 이동도를 반전층에서의 양자현상(버금띠 에너지와 파동함수)과 완화시간어림셈을 고려하여 계산하였다. 반전층에서의 양자현상은 슈뢰딩거 방정식과 포아슨 방정식을 자체 모순없이 계산하여 얻었다 완화시간은 밸리내 산란과 밸리사이 산란을 고려하여 계산하였다. 그 결과 Ge 함량이 증가됨에 따라 이동도가 증가되는 이유는 4-폴드 밸리에 존재하는 전자의 이동도보다 2-폴드 밸리에 존재하는 전자의 이동도가 약 3배 정도 크며 대부분의 전자가 밸리의 분리에 의해 2-폴드 밸리에 존재하기 때문이라는 것을 알 수 있었다. 한편, 포논 산란만을 고려한 이동도를 실험치와 일치시키기 위하여 전체 이동도에는 반전층 계면에서의 산란과 쿨롱 산란을 포함시켰다. 계산된 전계, 온도, 그리고 Ge 함량에 의존하는 이동도는 실험치와 근접하도록 변형포텐셜을 설정하였으며 정확한 결과를 위해서는 Si 에너지띠의 비포물성을 고려해야함을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.367-368
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• 2007

To investigate the 2nO thin films which are interested in the next generation of short wavelength LEDs and Lasers and UV photodetector with p-type inversion layer, the ZnO thin films were deposited by RF sputtering system. Gas ratios and work pressure is Ar : $O_2$ = 4 : 1 and 15 mTorr, respectively, and the purity of ZnO target is 5N. The ZnO thin films were deposited at 300, 450, and $650^{\circ}C$. The current-voltage, responsivity and quantum efficiency of devices were studied and compared with each devices.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.643-646
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• 2005

The gas hydrate exploration using seismic reflection data, the detection of BSR(Bottom Simulating Reflector) on the seismic section is the most important work flow because the BSR have been interpreted as being formed at the base of a gas hydrate zone. Usually, BSR has some dominant qualitative characteristics on seismic section i.e. Wavelet phase reversal compare to sea bottom signal, Parallel layer with sea bottom, Strong amplitude, Masking phenomenon above the BSR, Cross bedding with other geological layer. Even though a BSR can be selected on seismic section with these guidance, it is not enough to conform as being true BSR. Some other available methods for verifying the BSR with reliable analysis quantitatively i.e. Interval velocity analysis, AVO(Amplitude Variation with Offset)analysis etc. Usually, AVO analysis can be divided by three main parts. The first part is AVO analysis, the second is AVO modeling and the last is AVO inversion. AVO analysis is unique method for detecting the free gas zone on seismic section directly. Therefore it can be a kind of useful analysis method for discriminating true BSR, which might arise from an Possion ratio contrast between high velocity layer, partially hydrated sediment and low velocity layer, water saturated gas sediment. During the AVO interpretation, as the AVO response can be changed depend upon the water saturation ratio, it is confused to discriminate the AVO response of gas layer from dry layer. In that case, the AVO modeling is necessary to generate synthetic seismogram comparing with real data. It can be available to make conclusions from correspondence or lack of correspondence between the two seismograms. AVO inversion process is the method for driving a geological model by iterative operation that the result ing synthetic seismogram matches to real data seismogram wi thin some tolerance level. AVO inversion is a topic of current research and for now there is no general consensus on how the process should be done or even whether is valid for standard seismic data. Unfortunately, there are no well log data acquired from gas hydrate exploration area in Korea. Instead of that data, well log data and seismic data acquired from gas sand area located nearby the gas hydrate exploration area is used to AVO analysis, As the results of AVO modeling, type III AVO anomaly confirmed on the gas sand layer. The Castagna's equation constant value for estimating the S-wave velocity are evaluated as A=0.86190, B=-3845.14431 respectively and water saturation ratio is $50\%$. To calculate the reflection coefficient of synthetic seismogram, the Zoeppritz equation is used. For AVO inversion process, the dataset provided by Hampson-Rushell CO. is used.

• 한국환경과학회지
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• 제21권7호
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• pp.815-824
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• 2012

The purpose of this study was to analyze the meteorological characteristics of wintertime high PM10 concentration episodes in Busan. $PM_{10}$ concentration has been reduced for the past four years and recorded near or exceeded 100 ${\mu}g/m^3$ (national standard of $PM_{10}$). High concentration episodes in Busan were 6 case, $PM_{2.5}/PM_{10}$ ratio was 0.36~0.39(mean 0.55). High $PM_{10}$ concentration occurred during higher air temperature, more solar radiation and sunshine, lower relative humidity, and smaller cloud amount. Synoptically, it also occurred when Busan was in the center or the edge of anticyclone and when sea breeze intruded. An analysis of upper air sounding showed that high $PM_{10}$ concentration occurred when surface inversion layer and upper subsidence inversion layer existed, and when boundary layer depth and vertical mixing coefficient were low. An analysis of backward trajectory of air mass showed that high $PM_{10}$ concentration was largely affected by long range transport considering that it occurs when air mass is intruded from China.

• 해양환경안전학회지
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• 제15권3호
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• pp.165-171
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• 2009

1999년 10월, 12월의 국립수산과학원 정선관측 자료를 이용하여 수온역전 현상이 성층변동에 미치는 영향을 분석하였다. 10월, 12월 모두 수심 25-75m 사이에서 수온역전현상이 빈번하게 발생하며, 12월에는 표층 부근에도 수온역전현상이 나타났다. 고온, 고염분수인 쓰시마난류의 수평 이류가 10월, 12월에 나타나는 수온역전현상의 주원인으로 작용하며, 12월에는 연안역에서 외양역으로 수송되는 차가운 표층수의 영향이 함께 작용한다. 10월에는 북풍이 지속적으로 불지만 남해연안수가 외해역으로 확장하는 현상이 뚜렷하지 않는 반면, 북서풍계열의 풍속이 강해지고 쓰시마난류의 세력이 약해지는 12월에는 남해연안수가 상층부를 통해 외해역으로 확장하면서 수온역전현상을 나타나게 한다. 10월과 12월 모두 수온역전현상이 발생하는 해역을 따라 성층의 변동폭이 크게 나타난다.

• 설비공학논문집
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• 제9권2호
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• pp.104-111
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• 1997

The freezing phenomenon of saturated water with the supercooled region in a horizontal circular cylinder has been studied experimentally by using the holographic real time interferometry technique. From the experiments, it was found that there were three types of freezing patterns. The first is the annular ice layer growing from the cylinder surface at a high cooling rate; the next is the asymmetric ice layer at a moderate cooling rate; and the last is the instantaneous ice layer growth over the full region at lower cooling rate. As the water was coolde from room temperature to the subfreezing point passing through the density inversion point, the freezing pattern was largely affected by the inversion phenomenon, which had much effected the free convection and was susceptible to influences from the cooling rate. When the cooling rate is high, supercooling energy is released before the water is sufficientry mixed by free convection. On the other hand, when the cooling rate is low, there is much time for the water to be mixed by free convection. This seems to be the reason why the different ice layer growths occur.

• 대한전기학회논문지
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• 제33권6호
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• pp.203-211
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• 1984

MOS silicon solar cells have been developed using the fixed (interface) charge inherent to thermally oxidized silicon to induce an n-type inversion layer in 1-10 ohm-cm p-type silicon. Higher collection efficiencies are predicted than for diffused junction cells. Without special precautions a conversion efficiency of 14.2% is obtained. A MOS silicon solar cell is described in which an inversion layer forms the active area which is then contacted by means of a MOS grid. The highest efficiency is obtained when the resistivity of the substrate is high.

• 지구물리와물리탐사
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• 제10권2호
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• pp.138-146
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• 2007

이 연구에서 복소 전기비저항을 이용한 2차원 IP 모델링 알고리듬과 이를 이용한 역산 알고리듬을 개발하였다. 복소 전기비저항을 이용한 IP 탐사기법은 크기인 전기비저항과 위상정보를 제공함으로써 지하의 수리지질학적인 특성 및 내부 공극수 종류 등 다양한 정보의 제공이 가능하여 활용성이 확대되고 있다. IP 탐사 모델링 및 역산 알고리듬은 기존의 전기비저항 모델링 및 역산 알고리듬을 복소 연산을 포함하도록 확장함으로써 개발되었다. IP 모델링은 유한요소법을 이용한 2.5차원 모델링 알고리듬을, 역산 알고리듬으로는 평활화 제한을 가한 감쇠 최소자승법을 이용하였다. 모델링의 검증에는 슐럼버저 배열에 대하여 3차원 층서모형에 수치필터링을 이용한 1차원 모델링 결과와 비교하였으며, 쌍극자 배열에 대하여 고립이상체 모형에 3차원 적분방정식 IP 모델링 알고리듬과 비교하여 그 타당성을 확인하였다. 역산의 타당성을 확인하기 위하여 전기비저항 및 위상 중 하나는 배경매질과 동일하고 다른 물성 하나만 차이를 가지는 모델에 대하여 역산 실험을 수행하였으며, 전기비저항 및 위상 이상체를 정확히 영상화하고 있음을 확인하였다. 역산의 실제 복잡한 지질모델에의 적용성을 확인하기 위해, 3차원 층서구조 내에 두 번째 층의 일부에 위상 이상체가 존재하는 모형을 설정하여 수치실험을 수행한 결과 전기비저항 단면에서는 이상체가 잘 확인되지 않으나, 위상 단면에서 그 이상체가 명확히 나타나는 것을 확인하였다.

• 대한전자공학회논문지
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• 제20권1호
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• pp.45-49
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• 1983

Metal/insulator/n epi-layer/p+구조의 CID(controlled inversion device)를 제조하였다. I-V 특성 곡선에서 ON상태와 OFF상태사이에 부성저항(negative resistance)영역이 나타났다. CID를 제조하기 위해서 행한 산화층 형성 과정에서 600℃에서 5분간 산화시킨 소자의 스위칭 및 홀딩 전압은 각각 5.0V와 2.5V였다. 그리고 입사된 광에 의해서 스위칭 전압은 감소하였으나 홀딩 전압은 변하지 않았다.

• 대기
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• 제31권4호
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• pp.395-404
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• 2021

In order to investigate downslope windstorm by using more detailed observation, we observed 6 cases at 3 sites - Inje, Yongpyeong, and Bukgangneung - during "3-D Meteorological Observation Project in Yeongdong region of Gangwon province, South Korea in 2020." The results from analysis of the project data were as follows. First, AWS data showed that a subsidence inversion layer appeared in 800~700 hPa on the windward side and 900~850 hPa on the leeward side. Second, before strong wind occurred, the inversion layer had descended to about 880~800 hPa. Third, with mountain wave breaking, downslope wind was intensified at the height of 2~3 km above sea level. After the downslope wind began to descend, the subsidence inversion layer developed. When the subsidence inversion layer got close to the ground, wind peak occurred. In general, UM (Unified Model) GDAPS (Global Data Assimilation Prediction System) have had negative bias in wind speed around peak area of Taebaek mountain range, and positive bias in that of East Sea coast area. The stronger wind blew, the larger the gap between observed and predicted wind speed by GDAPS became. GDAPS predicted strong p-velocity at 0600 LST 25 Apr 2020 (4^th case) and weak p-velocity at 2100 LST 01 Jun 2020 (6^th case) on the lee-side of Taebaek mountain range near Yangyang. As hydraulic jump theory was proved, which is known as a mechanism of downslope windstorm in Yeongdong region, it was confirmed that there is a relationship between p-velocity of lee-side and wind speed of eastern slope of Taebaek mountain range.