SAW Self-Aligned Selectively Grown W-GAte) MOSFETs (SAW (Self-Algined Selectively Grown W-Gate) MOSFETs의 제작 및 특성 분석

황성민,노광명,정명준,허민,정하풍,서정원,박찬광,고요환,이대훈,Hwang, Seong-Min,Rho, Kwang-Myoung,Chung, Myung-Jun,Huh, Min,Jeong, Ha-Poong,Suh, Jeong-Won,Park, Chan-Kwang,Koh, Yo-Hwan,Lee, Dai-Hoon 대한전자공학회 1995 전자공학회논문지-A Vol.32 No.6

We proposed SAW (Self-Algined Selectively Grown W-Gate) MOSFET structure, and strudied electrical characteristics of the fabricated SAW MOSFETs. The threshold volgate of 0.21${\mu}$m SAW NMOSFET was 0.18 V and that of 0.24 ${\mu}$m SAW PMOSFET was -0.16 V. The subthreshold slope was 74 mV/decade for NMOSFET and 82 mV/decade for PMOSFET. The maximum transconductance of NMOSFET and PMOSFET, at V$_{GS}$=2.5 V and V$_{DS}$=1.5 V, were260 mS/mm and 122 mS/mm. The measured saturation drain current at V$_{GS}$=V$_{DS}$ =2.5 V was 0.574 mA/${\mu}$m for NMOSFET and -0.228 mA/${\mu}$m for PMOSFET. The gate resistance of SAW MOSFET was about m$\Omega$cm and the n+-p junction capacitance of SAW MOSFET was about 10% lowas than that of the conventional MOSFET's.

Improvement of Transglycosylation Efficiency using a Glycosynthase Mutant derived from Thermoplasma acidophilum ${\alpha}$-Glucosidase

황성민,서성화,박인명,최경화,김도만,차재호,Hwang, Sung-Min,Seo, Seong-Hwa,Park, In-Myoung,Choi, Kyoung-Hwa,Kim, Do-Man,Cha, Jae-Ho The Korean Society for Microbiology and Biotechnol 2012 한국미생물·생명공학회지 Vol.40 No.2

Glycosynthase는 친핵성 아미노산을 비친핵성 아미노산으로 치환하여 당전이 산물의 가수분해를 막아서 당전이 효율을 증가시킬 수 있다. 이전 연구에서 본 실험실은 열에 안정하고 산에 강한 Thermoplasma acidophilum 유래의 ${alpha}$-glucosidase (AglA)가 당전이 활성이 있음을 입증하였으나 시간이 지남에 따라 당전이 산물이 가수분해 되었다. 이러한 AglA의 당전이 효율을 개선하기 위하여 친핵성 아미노산인 아스파라긴산을 글리신으로 치환하였다. 이 치환된 glycosynthase는 니켈 친화력 크로마토그래피를 통하여 정제되었으며, 정제된 돌연변이 단백질의 배당체를 합성하는 능력이 말토오스를 공여체로 그리고 p-nitrophenyl-${alpha}$-D-glucopyranoside($pNP{\alpha}G$)를 수용체로, 그리고 $pNP{\alpha}G$가 당공여체 및 수용체로 이용될 수 있는지 검사하였다. Glycosynthase를 이용한 당전이 산물의 수율은 약 42.5%를 보였으며 시간이 지남에 따라서 가수분해되지 않았다. 박막 크로마토그래피법을 이용한 반응산물의 분석은 수용체의 높은 농도에서 기존의 효소보다 많은 양의 배당체를 합성할 수 있음을 보여주었고, 특히 중성보다 낮은 pH 영역에서 가장 높은 활성을 보여줌을 확인하였다. 이러한 결과는 glycosynthase가 산업적으로 배당체를 합성하는데 유용성이 크다는 것을 나타낸다. Glycosynthase is an active site nucleophile mutant enzyme, prepared from glycosidase, which is capable of synthesizing oligosaccharide derivatives without the hydrolysis of the product. Thermoacidophilic ${\alpha}$-glucosidase of Thermoplasma acidophilum (AglA) exhibits a transglycosylating activity yielding various glycosides. AglA was converted to glycosynthase by the substitution of the catalytic nucleophile Asp-408 residue into non-nucleophile glycine in order to increase its ability to synthesize various glycosides by transglycosylation. The glycosynthase mutant was purified by Ni-NTA chromatography and its glycoside-synthesizing activity was measured by using an external nucleophile, sodium formate buffer, providing maltose as a donor and p-nitrophenyl-${\alpha}$-D-glucopyranoside ($pNP{\alpha}G$) as an acceptor, respectively. In addition, $pNP{\alpha}G$ was examined for its feasibility to act as both a donor and an acceptor, and products were compared with those of the wildtype enzyme. The mutant enzyme was found to catalyze the formation of a specific product from $pNP{\alpha}G$ with a yield of 42.5% without further hydrolysis, while the wild-type enzyme produced two $pNP{\alpha}G$ products at low yields. The results demonstrate the possibility of satisfactory yields for the reactions in the presence of small amounts of acceptor, and demonstrate that the high activity of the mutant, at pHs below neutrality, was applicable in the transfer of glucose from the natural donor.

AHP기법을 이용한 교통상황 판단의 중요도 평가에 관한 연구

황성민(Hwang, Seong-Min),이병주,서승환,성수련,남궁문(NamGung, Mun) 대한교통학회 2010 대한교통학회 학술대회지 Vol.62 No.-

열화상 영상 잡음 제거 알고리즘 성능 비교

황성민(Seong-Min Hwang),유광현(Gwang-Hyun Yu),나지르 샤히드(Nazeer Shahid),신도성(DoSeong Sin),김진술(Jinsul Kim),김진영(Jinyoung Kim) 한국정보기술학회 2018 Proceedings of KIIT Conference Vol.2018 No.11

학술발표회 초록 ( 열역학 (Ⅰ) ) : 키토산막에서 에탄올 수용액의 투과거동에 관한 연구

황성민(Seong Min Hwang),정욱(Wook Chung),김희택(Hee Taik Kim),배성렬(Seong Youl Bae) 한국화학공학회 1993 추계학술발표회 Vol.- No.-

자기 주도적 학습이 강화된 조별 발표 물리 수업이 마이스터고 학생의 과학 관련 태도와 의사소통능력에 미치는 영향

황성민(Seong-Min Hwang),최혁준(Hyukjoon Choi) 한국교원대학교 뇌기반교육연구소 2020 Brain, Digital, & Learning Vol.10 No.4

The purpose of this study was to investigate the effects of group-led presentations with enhanced self-directed learning on science-related attitudes and communication skills of Meister high school students. Pre- and post-tests on science-related attitudes and communication skills were conducted, and surveys were conducted to determine class satisfaction. The conclusion of this study was as follows; First, the application of group presentations, which strengthened self-directed learning, positively changed students’ science-related attitudes. Second, the application of group presentations, which strengthened self-directed learning, did not give a positive result to the students communication ability.

Thermoplasma acidophilum 유래 α-glucosidase로 부터 생산된 glycosynthase 돌연변이 단백질의 개선된 당전이 효율

황성민 ( Sung Min Hwang ),서성화 ( Seong Hwa Seo ),박인명 ( In Myoung Park ),최경화 ( Kyoung Hwa Choi ),김도만 ( Do Man Kim ),차재호 ( Jae Ho Cha ) 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 2012 한국미생물·생명공학회지 Vol.40 No.2

Glycosynthase는 친핵성 아미노산을 비친핵성 아미노산으로 치환하여 당전이 산물의 가수분해를 막아서 당전이 효율을 증가시킬 수 있다. 이전 연구에서 본 실험실은 열에 안정하고 산에 강한 Thermoplasma acidophilum 유래의 α-glucosidase (AglA)가 당전이 활성이 있음을 입증하였으나 시간이 지남에 따라 당전이 산물이 가수분해 되었다. 이러한 AglA의 당전이 효율을 개선하기 위하여 친핵성 아미노산인 아스파라긴산을 글리신으로 치환하였다. 이 치환된glycosynthase는 니켈 친화력 크로마토그래피를 통하여 정제되었으며, 정제된 돌연변이 단백질의 배당체를 합성하는 능력이 말토오스를 공여체로 그리고 p-nitrophenyl-α-D-glucopyranoside(pNPαG)를 수용체로, 그리고 pNPαG가 당공여체 및 수용체로 이용될 수 있는지 검사하였다. Glycosynthase를 이용한 당전이 산물의 수율은 약 42.5%를 보였으며 시간이 지남에 따라서 가수분해되지 않았다. 박막 크로마토그래피법을 이용한 반응산물의 분석은 수용체의 높은 농도에서 기존의 효소보다 많은 양의 배당체를 합성할 수 있음을 보여주었고, 특히 중성보다 낮은 pH 영역에서 가장 높은 활성을 보여줌을 확인하였다. 이러한 결과는 glycosynthase가 산업적으로 배당체를 합성하는데 유용성이 크다는 것을 나타낸다. Glycosynthase is an active site nucleophile mutant enzyme, prepared from glycosidase, which is capable of synthesizing oligosaccharide derivatives without the hydrolysis of the product. Thermoacidophilic α-glucosidase of Thermoplasma acidophilum (AglA) exhibits a transglycosylating activity yielding various glycosides. AglA was converted to glycosynthase by the substitution of the catalytic nucleophile Asp-408 residue into non-nucleophile glycine in order to increase its ability to synthesize various glycosides by transglycosylation. The glycosynthase mutant was purified by Ni-NTA chromatography and its glycoside-synthesizing activity was measured by using an external nucleophile, sodium formate buffer, providing maltose as a donor and pnitrophenyl- α-D-glucopyranoside (pNPαG) as an acceptor, respectively. In addition, pNPαG was examined for its feasibility to act as both a donor and an acceptor, and products were compared with those of the wildtype enzyme. The mutant enzyme was found to catalyze the formation of a specific product from pNPαG with a yield of 42.5% without further hydrolysis, while the wild-type enzyme produced two pNPαG products at low yields. The results demonstrate the possibility of satisfactory yields for the reactions in the presence of small amounts of acceptor, and demonstrate that the high activity of the mutant, at pHs below neutrality, was applicable in the transfer of glucose from the natural donor.

에탄올 수용액의 Pervaporation 에서의 투과거동

배성렬,이한선,황성민,김희택,히데히로구마자와 ( Seong Youl Bae,Han Sun Lee,Seong Min Hwang,Hee Taik Kim,Hidehiro Kumazawa ) 한국공업화학회 1994 공업화학 Vol.5 No.1

CTA(cellulose triacetate) 막을 이용한 물과 에탄올의 투과증발(pervaporation) 막분리에서 수착과 투과실험으로부터 용해-확산 투과기구의 modeling 및 그 함수형과 parameters에 대한 해석을 시도하였다. 순성분들의 수착 data를 사용하여 Flory-Huggins 식으로 계산한 3 성분계(에탄올/물/CTA) 수착평형 조성을 추산하여 실측치와 비교하였다. 막 내부의 조성과 액상의 평형 조성간에 열역학적 평형 관계식을 적용하기 위해 막 내 겉보기 활동도를 Wilson식과 Van Laar식으로 상관시켰다. 투과속도식은 한 성분의 투과속도가 그 성분의 막 내 농도구배에 비례하며, 또한 확산계수의 농도 의존성이 에탄올 농도만의 지수함수라고 가정하여 물과 에탄올 투과속도를 계산하였으며 이는 실측치와 잘 일치하였다. 한성분의 투과속도와 수착량이 다른 성분에 비해 현저히 작은 경우에는 대류항을 무시할 수 없음을 알았고, 온도가 높고, 투과측 압력이 낮을수록 투과속도와 투과선택도가 증가하였다. In the process of pervaporation separation for aqueous ethanol solution through cellulose tri-acetate(CTA) membrane, the modelling on the solution-diffusion permeation mechanism was built up on the basis of sorption and permeation experimental results. Also its function type and parameter were examined. The composition of sorption equilibrium in three component system(Ethanol/Water/CTA) were compared with the calculated value by Flory-Huggins` equation using the pure component sorption data. In order to apply the thermodynamic equilibrium relationship between the membrane free composition in the membrane and the equilibrium composition in the liquid phase, the apparent activity coefficients in the membrane were correlated by Wilson and Van Laar type equations. Due to the nonideal behaviour in this system, however, the results were not satisfied. Diffusion equations were expressed with the concentration gradient considering permeate alone, and a concentration-dependent diffusion coefficient which includes a parameter was used. And this model was fitted with the measured permeation rates. If the permeation rate and the amount of sorption of one component were much larger than those of the other, the bulk flow term could not be negligible. The flux and selectivity were increased with increasing temperature, and with decreasing downstream pressure.

철도안전관리체계 국내외 사례 및 발전방안 고찰

이창민(Chang-min Lee),황성민(Seong-min Hwang),안현근(Hyun-geun An),박지훈(Ji-hoon Park),박정수(Jung-soo Park) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05

2003년 대구 지하철 화재 참사를 계기로 철도안전에 대한 인식이 변화되었으며, 2004년부터는 철도역사상 많은 변화가 발생한 시작점이다. 2004년 3월부터 개정된 철도안전법은 과거의 철도안전관리기법에서 탈피하여 새로운 안전관리체계 도입을 요구하게 되었다. 이에 국제기준과의 차이점을 찾아내어 국내는 국제기준에 부합하도록 변경검토를 하여야 한다. 본 연구에서는 첫째 2004년 이후 급격하게 변화한 철도운행 반경을 분석하고, 둘째 철도안전관리체계 정립을 위한 국내외 적용되는 다양한 기법을 소개한다. 셋째 철도사고 발생률 국제비교 및 문제점 제시를 통해 사고예방활동, 사고저감대책을 정리하고 철도안전의 미래상과 철도안전대책을 제시하고자 한다. Daegu metro fire in 2003,. The awareness of the railway safety on railway platforms since 2004, and change many changes have occurred in the starting point. The Railroad safety Act as amended in March 2004, broke away from railways safety management style of the past with new safety management system require the adoption. In noticed a difference with international standards both at the national and international standards should be required to enable change to conform to the review. In this study, the first railroad operations changed dramatically since 2004, applied at home and abroad for the safety management system for railways, and second for a radius of a variety of techniques. Here. Third rail accident rate for international Student and the Reduction Strategies of incident and railway safety, accident prevention measures through the presentation of vision problems and to provide safety measures.do.

GaN 완충층 두께가 GaN 에피층의 특성에 미치는 영향

조용석,고의관,박용주,김은규,황성민,임시종,변동진,Jo, Yong-Seok,Go, Ui-Gwan,Park, Yong-Ju,Kim, Eun-Gyu,Hwang, Seong-Min,Im, Si-Jong,Byeon, Dong-Jin 한국재료학회 2001 한국재료학회지 Vol.11 No.7

Metal organic chemical vapor deposition (MOCVB)법을 사용하여 sapphire (0001) 기판 위에 GaN 환충층을 성장하고, 그 위에 GaN 에피층을 성장하였다. GaN 완충층은 55$0^{\circ}C$에서 약 26 nm에서 130 nm까지 각각 다른 두께로 성장하였고, GaN 에피층은 110$0^{\circ}C$에서 약 4 $\mu\textrm{m}$의 두께로 성장하였다. GaN 완충층 성장 후 atomic force microscopy (AFM)으로 표면 형상을 측정하였다. GaN 완충층의 두께가 두꺼워질수록 GaN 에피층의 표면이 매끈해지는 것을 scanning electron microscopy (SEM)으로 관찰하였다. 이것으로 GaN 에피층의 표면은 완충층의 두께와 표면 거칠기와 관계가 있다는 것을 알 수 있었다. GaN 에피층의 결정학적 특성을 double crystal X-ray diffraction (DCXRD)와 Raman spectroscopy로 측정하였다. 성장된 GaN 에퍼층의 광학적 특성을 photoluminescence (PL)로 조사한 결과 두께가 두꺼운 완충층 위에 성장된 에퍼층의 결정성이 더 좋은 반면, 내부 잔류응력은 증가하는 결과를 보였다. 이러한 사실들로부터 완충층의 두께가 두꺼워짐에 따라 내부 자유에너지가 감소하여 에피층 성장시 측면성장을 도와 표면이 매끈해지고, 결정성이 좋아졌다. GaN buffer layer and epilayer have been grown on sapphire (0001) by metal organic chemical vapor deposition (MOCVD). GaN buffer layer ranging from 26 nm to 130 nm in thickness was grown at 55$0^{\circ}C$ prior to the 4 $\mu\textrm{m}$ thick GaN epitaxial deposition at 110$0^{\circ}C$. After GaN buffer layer growth, buffer layer surface was examined by atomic force microscopy (AFM). As the thickness of GaN buffer layer was increased, surface morphology of GaN epilayer was investigated by scanning electron microscopy (SEM). Double crystal X-ray diffraction (DCXRD) and Raman spectroscopy were employed to study crystallinity of GaN epilayers. Optical properties of GaN epilayers were measured by photoluminescence (PL). The epilayer grown with a thin buffer layer had rough surface, and the epilayer grown with a thick buffer layer had mirror-like surface of epilayer. Although the stress on the latter was larger than on the former, its crystallinity was much better. These results imply that the internal free energy is decreased in case of the thick buffer layer. Decrease in internal free energy promotes the lateral growth of the GaN film, which results in the smoother surface and better crystallinity.