• 전자공학회논문지A
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• 제32A권1호
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• pp.103-110
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• 1995

Trench-Gate SOI LIGBT with improved latch-up capability has been proposed and verified by MEDICI simulation. The new SOI LIGBT exhibits 6 time larger latch-up capability of the new device is almost preserved independent of lifetime. the large latch-up capability of the new SOI LIGBT may be realized due to the fact that the hole current in the new device would bypass through the shorted cathode contact without passing the p-well region under the n+ cathode. Forward voltage drop is increased by 25% when a epi thickness is 6$\mu$m. However, the increase of the forward voltage is negligible when the epi thickness is increased to 10$\mu$m. It is found that the swithcing time of the new device is almost equal to the conventional devices. Evaluated breakdown voltage of proposed SOILIGBT is 250 V and that of the conventional SOI LIGBT is 240 V, where the thickness of the vuried oxide and n- epi is 3$\mu$m and 6$\mu$m, respectively.

• Child Health Nursing Research
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• 제17권4호
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• pp.281-287
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• 2011

Purpose: The study was done to explore growth variation in head circumference (HC) in extremely premature infants (EPI) with brain injury. Methods: A retrospective cohort study was conducted with 79 cohort samples from the archives of the catch-up growth project. Mean age of the infants was 29.2 weeks of gestation and mean HC, 27.1 cm at birth. Their HC measurements were retrieved from the archives up to 6 month of corrected age (CA) and analyzed against history of brain injury during hospitalization. Results: Overall growth retardation in HC was observed in the cohort sample compared to longer gestation premature infants. EPI with brain injury showed decreased HC compared to infants without brain injury, and resulting growth variation across 6 month of CA. Highest retardation in HC growth was observed in male infants with brain injury. Conclusion: Extreme preterm birth itself may function as a major obstacle against HC growth toward term age in EPI. Sustainability of brain injury could be observed with higher HC growth retardation after term. Evolutionary favor to female infants may exist in HC growth of EPI. Intensive education on HC monitoring is highly suggested for parents of EPI, particularly with children with brain injury.

• 한국광학회지
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• 제22권3호
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• pp.141-150
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• 2011

현재까지 더 좋은 성능의 LED 램프 패키지 구조의 개발을 위해 많은 연구가 진행되어 왔음에도 불구하고 아직 LED 램프 패키지 설계에 관한 표준화된 이론이나 지침 같은 것들이 마련되지 못한 것으로 판단된다. 이에 본 논문에서는 먼저 Monte Carlo photon simulation 기법을 이용하여 InGaN/Sapphire LED의 칩 구조 및 Epi-up 혹은 Epi-down 칩 부착 방식을 광추출효율 관점에서 분석하였다. 그리고 분석결과를 바탕으로 LED 램프 패키지 설계에 관한 기본 지침을 마련하였다. 이와 같이 마련된 설계지침은 관련 기업이나 연구기관에서, LED 램프의 구체적 응용분야에 따라 최적화된 패키지 구조를 설계하는 데에 중요하게 활용될 수 있을 것으로 기대된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.524-529
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• 2002

In this paper, we report the development of two DEM (digital elevation model) generation algorithms over urban areas from an IKONOS stereo pair. One ("EpiMatch") is originally developed for SPOT images and modified for IKONOS images. It uses epipolar geometry for accurate DEM generation. The other is based on graph-cut algorithm in 3D voxel space. This algorithm is believed to work better on height discontinuities than EpiMatch. An IKONOS image pair over Taejon city area was used for tests. Using ground control points obtained from differential GPS, camera model was set up and stereo matching applied. As a result, two DEMs over urban areas were produced. Within a DEM from EpiMatch small houses appear as small "cloudy" patches and large apartment and industrial buildings are visually identifiable. Within the DEM from graph-cut we could achieve better height information on building boundaries. The results show that both algorithms can generate DEMs from IKONOS images although more research is required on handling height discontinuities (for "EpiMatch") and on faster computation (for "Graph-cut").

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권1호
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• pp.51-55
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• 2001

This study was conducted to establish a plant cell culture system for the production of medically important secondary metabolites from Xanthium strumarium. The effects of plant growth regulators including NAA, 2,4-D, kinetin, and ABA were examined in terms of callus induction, maintenance of callus and suspension cultures. It was shown that callus was induced upon treatment with NAA while embryo was induced after treatment with 2,4-D. Callus formation was further improved by treatment with ABA and NAA. The level of callusing increased by 17-29% for the seed case, cotyledon, leaf, and hypocotyl and by 96% in the case of the root. Suspension cell lines were established using calli produced from cotyledon, hypocotyl and root and cultured at 25$\^{C}$ under light conditions. The cells grew up to 15g/L with NAA 2ppm, BA 2ppm, and ABA 1ppm treatment. Supernatants of suspension cultures of cell lines derived from coyledon and hypocotyl produced some distinctive secondary metabolites, one of which was identified as 8-epi-tomentosin, which belongs to the xanthanolides. The amounts of 8-epi-tomentosin produced by the cotyledon- and hypocotylderived cell lines were 13.4mg/L and 11.0mg/L, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.288-291
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• 2004

Due to the charge compensation effect, SOI(Silicon-On-Insulator) LIGBT with dual-epi layer have been found to exhibit both low forward voltage drop and high static breakdown voltage. In this paper, electrical characteristics of the SOI LIGBT with dual-epi structure is presented. Trenched anode structure is employed to obtain uniform current flowlines and shorted anode structure also employed to prevent the fast latch-up. Latching current density of the proposed LIGBT with $T_1=T_2=2.5{\mu}m,\;N_1=7{\times}10^{15}/cm^3,\;N_2=3{\times}10^{15}/cm^3$ is $800A/cm^2$ and breakdown voltage is 125V while latching current density and breakdown voltage of the conventional LIGBT is $700A/cm^2$ and 55V.

• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.551-554
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• 2014

This paper was showed latch up characteristics of super junction power MOSFET by parasitic thyristor according to trench etch angle. As a result of research, if trench etch angle of super junction MOSFET is larger, we obtained large latch up voltage. When trench etch angle was $90^{\circ}$, latch up voltage was more 50 V. and we got 700 V breakdown voltage. But we analyzed on resistance. if trench etch angle of super junction MOSFET is larger, we obtained high on resistance. Therefore, we need optimal point by simulation and experiment for solution of trade off.

• 환경영향평가
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• 제24권6호
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• pp.593-606
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• 2015

녹색도시지수(GCI), 환경성과지수(EPI), 도시생물다양성지수(CBI)는 환경적 측면에서 도시의 객관적 평가를 위해 국제적으로 활발히 활용되고 있다. 하지만 인구밀도나 도시규모 등 도시의 특성이 다른 국내 상황에 이들을 직접 적용하는 것은 어려움이 있다. 따라서, 본 연구는 도시의 환경개선과 생물다양성 향상을 위하여 지자체 스스로 환경문제를 진단하고 문제점을 도출하여 환경정책으로 활용 가능한 한국형 도시평가지표 개발을 목적으로 하고 있다. 이를 위하여 기존에 사용되는 국제지표들의 장단점을 분석하고, 이를 토대로 한국적 상황에 부합하는 지표를 도출하였다. 지표는 생물다양성, 생활환경, 생태계서비스, 행정 및 관리 4개 영역 20개 항목으로 구성된 한국형 '지속가능한 도시의 평가지표(ESCI)'를 개발하였으며, 도시생태현황지도가 작성된 서울, 인천, 수원, 원주, 계룡 등 5개 도시에 적용하였다. 그 결과, 제시된 한국형 지속가능한 도시의 평가지표는 대도시의 경우 거의 모든 항목을 적용할 수 있었으나 중소도시는 일부만 적용할 수 있었다. 지표 적용을 모든 도시로 확대하기 위해서는 지자체별로 통일된 도시생태 현황지도의 작성과 필요한 자료구축이 선행되어야하며, 도시규모 및 자료구축 수준에 따라 지표 항목을 점진적으로 적용하는 것이 바람직하다.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3440-3447
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• 2022

The accuracy of the photoatomic cross-section data is of great importance in the field of radiation protection, particularly in the characterization of radiation shielding materials. With the release of the latest and probably the most accurate photoatomic data library, EPDL2017, the need to re-evaluate all the existing and already established mass attenuation coefficients (MACs) of all radiation shielding materials arises. The MACs of several polymers, alloy-based, glasses, and building materials used in a nuclear medicine facility were investigated using the EPDL2017 library embedded in EpiXS software and were compared to MACs available in the literature. The relative differences between MAC_EpiXS and MACXCOM were negligible, ranging from 0.02% to 0.36% for most materials. However, for material like a glass comprising of elements Te and La evaluated near their corresponding K-edge energies, the relative differences in MACs increased up to 1.46%. On the other hand, a comparison with MACs calculated based on EPDL97 (a predecessor of EPDL2017) revealed as much as a 6.61% difference. Also, it would seem that the changes in MACs were more evident in the materials composed of high atomic number elements evaluated at x-ray energies compared to materials composed of low atomic number elements evaluated at gamma-ray energies.

• 핵의학기술
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• 제25권2호
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• pp.35-40
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• 2021

신사구체여과율(glomerular filtration rate, GFR)은 신장 질환의 진단, 치료 및 추적 관찰에 중요한 지표이며, 건강인에서도 약제사용, 신장이식 공여자의 신장 평가 등에 사용된다. GFR 검사의 표준방법은 외인성 표지자인 이눌린(inulin)을 연속 주입하여 측정하는 방법이나, 시간이 많이 소요되고 검사 방법이 복잡하기 때문에, 혈청 크레아티닌 농도로 계산한 추정사구체여과율(estimated glomerular filtration rate, eGFR)을 대신 사용한다. 그러나 크레아티닌은 연령, 성별, 근육량 등에 영향을 받는 것으로 알려져 있으며, 현재 많이 사용되는 추정사구체여과율 공식에는 성인의 경우 Cockroft-Gault 공식, Modification of Diet in Renal Disease(MDRD) 공식, Chronic kidney Disease Epidemiology Collaboration (CKD-EPI) 공식 등이 있고, 소아의 경우 Schwartz 공식을 사용하고 있다. ^99mTC diethylenetriaminepentaacetic acid(^99mTc-DTPA)를 사용한 신사구체여과율(glomerular filtration rate, GFR) 측정은 이눌린을 대체 할 수 있어 현재 사용되고 있다. 이에 ^99mTc-DTPA를 이용하여 측정한 신사구체 여과율과 CKD-EPI 공식을 이용한 추정사구체여과율을 비교하여 보았다. 서울 아산병원을 내원한 신장이식 공여자 200명(남성 96명, 여성 104명, 47.3세±12.7)을 대상으로 ^99mTc-DTPA(0.5 mCi, 18.5 MBq)를 정맥투여 하고 획득된 plasma(Two-plasma-sample-method, TPSM)를 계측하여 신사구체여과율(glomerular filtration rate, GFR)을 측정하였다. 혈청 크레아티닌 농도를 근거로 chronic kidney disease epidemiology collaboration (CKD-EPI) 공식을 이용하여, 추정사구체여과율(estimated glomerular filtration rate, eGFR)을 도출하였다. 신장이식 공여자 200명(남성 96명, 여성 104명, 47.3세±12.7)을 대상으로 ^99mTc-DTPA를 사용하여 측정된 신사구체여과율 평균값은 97.27±19.46 (GFR, ml/min/1.73m²)이고 CKD-EPI 공식을 이용한 추정사구체여과율 (estimated glomerular filtration rate, eGFR) 평균값은 96.84±17.74(CKD-EPI, ml/min/1.73m²), 혈청 크레아타닌의 농도는 0.84±0.39 (mg/dL)이다. 혈청 크레아티닌 근거 추정사구체여과율에 대한 ^99mTc-DTPA 신사구체여과율의 회귀식은 Y= 0.5073X + 48.186, 상관계수는 0.698이었다.(P<0.01)혈청 크레아티닌 근거 추정사구체여과율에 대한 ^99mTc-DTPA 신사구체여과율의 Difference(%)는 1.52±18.28 이었다. ^99mTC-DTPA를 이용해서 측정된 신사구체여과율과 혈청 크레아티닌 농도에 기반하여 도출된 추정사구체여과율에 대한 상관계수는 0.698로 중등도 정도의 상관성을 확인할 수 있었다. 이는 추정사구체여과율은 연령, 성별, 근육 양 등 신장 외적인 요소에 영향을 받고 신장질환자를 대상으로 만든 공식을 사용하는 원인에 기인하는 것으로 추정된다. 신장 질환의 진단, 치료 및 추적 관찰, 신장이식 공여자의 신장 평가 등에 사용되는 신사구체여과율 측정에 ^99mTc-DTPA를 사용함으로써 신뢰성 있는 결과를 임상에 제공할 수 있다.