혼합소스 HVPE 방법에 의해 성장된 육각형 Si 결정

이강석,김경화,박정현,김소윤,이하영,안형수,이재학,전영태,양민,이삼녕,전인준,조채용,김석환,Lee, Gang Seok,Kim, Kyoung Hwa,Park, Jung Hyun,Kim, So Yoon,Lee, Ha Young,Ahn, Hyung Soo,Lee, Jae Hak,Chun, Young Tea,Yang, Min,Yi, Sam Nyung,Jeon, I 한국결정성장학회 2021 韓國結晶成長學會誌 Vol.31 No.3

고체 재료인 Si, Al 그리고 Ga을 혼합하는 혼합소스 수소화물기상 방법에 의해 육각형 Si 결정을 성장하였다. 새로 고안된 상압의 혼합소스 수소화물기상 방법에서는 1200℃의 고온에서 GaCl_n, AlCl_n 그리고 SiCl_n 가스 사이의 상호작용에 의해 핵이 형성된다. 또한 Si과 HCl 가스의 급격한 반응에 의해 높은 분압을 가진 전구 기체를 발생시키는 구조로 설계 되었다. 주사 전자 현미경(FE-SEM), 에너지 분산형 X-선 분광법(EDS), 고해상도 X-선 회절(HR-XRD) 그리고 라만 스펙트럼을 통하여 육각형 Si 결정의 특성을 확인하였으며, Si 산업 분야에서 새로운 소재로서 응용성이 기대된다. Hexagonal shape Si crystals were grown by the mixed-source hydride vapor phase epitaxy (HVPE) method of mixing solid materials such as Si, Al and Ga. In the newly designed atmospheric pressure mixed-source HVPE method, nuclei are formed by the interaction between GaCl_n, AlCl_n and SiCl_n gases at a high temperature of 1200℃. In addition, it is designed to generate a precursor gas with a high partial pressure due to the rapid reaction of Si and HCl gas. The properties of hexagonal Si crystals were investigated through scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), high-resolution X-ray diffraction (HR-XRD), and Raman spectrum. From these results, it is expected to be applied as a new material in the Si industry.

공침-부선기술에 의한 수용액 시료 중 흔적량 수은 [Hg(II)]의 분리 및 농축

이강석,최희선,김선태,김영상,Lee Kang-Seok,Choi Hee-Seon,Kim Seon-Tae,Kim Young-Sang 대한화학회 1991 대한화학회지 Vol.35 No.4

수용액 시료 중 흔적량 수은[Hg(II)]을 공침-부선기술에 의하여 분리-농축하는 방법에 관하여 연구하였다. 물시료 1000ml에 0.1M Ce$^{3+}$ 용액 3.0 ml를 가하고, 1.0M NaOH 용액으로 pH를 11.0으로 되게 조절하여 Hg(II)를 Ce(OH)$_3$와 함께 공침시켰다. 0.1${\%}$ sodium oleate 용액 2.0 ml를 가하여 만든 소수성 침전을 질소기체로 bubbling하여 용액 표면으로 띄웠다. 뜬 침전을 감압 플라스크에 모으고 2.0M HNO$_3$ 5.0 ml 로 녹였다. 탈이온수로 용액을 묽혀 25.00 ml로 정확히 만들었다. Hg(II)의 함량을 냉증기-원자흡수 분광법으로 정량하였다. 정량과정에서 Ag$^+$, Br$^-$, I$^- $ 등의 간섭은 관찰되지 않았다. 고려대학교 서창캠퍼스의 폐수에서 Hg(II)의 분석결과는 1.98 ng/ml 이었고, 이 값에 대한 상대표준편차는 3.6${\%}$이었다. 또 이 폐수에 1.0과 2.0ng/ml의 Hg(II)를 첨가하여 분석한 회수율은 각각 95와 91${\%}$이었다. 이런 결과로부터 본 분석법이 물시료 중 흔적량 Hg(II)의 정량에 꽤 정확하고 재현성이 있음을 확인할 수 있었다. The separative preconcentration of trace mercury[Hg(II)] in a water sample was studied by a coprecipitation flotation technique. The trace Hg(II) was precipitated together with Ce(OH)$_3$ by adding 3.0 ml of 0.1M Ce$^{3+}$ solution to 1,000 ml of water sample and adjusting pH to 11.0 with 1.0M NaOH solution. The hydrophobic precipitate[Ce(OH)$_3$-Hg(OH)$_2$], which was formed by adding 2.0 ml of 0.1${\%}$ ethanolic sodium oleate solution, were floated on the surface with an aid of tiny nitrogen gas bubbles. The floated materials were quatitatively collected in a suction flask and dissolved with 5.0 ml of 2.0M HNO$_3$. The solution was marked to 25.00 ml with a deionized water. The content of Hg(II) was determined by cold vapor atomic absorption spectrophotometry. Any interferences of concomitants such as Ag$^+$, Br$^-$, I$^- $, etc. were not observed on the whole procedure. The analytical result showed that Hg(II) found in the wastewater of Seochang Campus, Korea University was 1.98 ng/ml with the relative standard deviation of 3.6${\%}$. And recoveries of Hg(II) in the wastewater into which 1.0 ng/ml and 2.0 ng/ml were added were 95${\%}$ and 91${\%}$, respectively. From such results, this procedure could be concluded to be tolerably accurate and reproducible for the determination of trace mercury in a water sample.

자연형 호안공법을 적용한 소하천의 수리특성 분석

이강석,박종화,연규방,Lee, Gang-Seuk,Park, Jong-Hwa,Yeon, Kyu-Bang 한국관개배수위원회 2010 한국관개배수논문집 Vol.17 No.2

Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods applicable to nature-like streams. Stream restoration projects aim to maintain or increase ecosystem goods and services while protecting downstream and coastal ecosystems. Fields environmental monitoring such as flow discharge and precipitation were conducted along the Idong stream for amount of channel zone change in 2007. This study selected three monitoring positions to measure the water level and discharge of flowing water. A stage-discharge relation is obtained from direct discharge measurements for three stations by fitting an empirical relationship to the data set. Since discharge measures are made only for low flow conditions, a curve of discharge against stage can then be built by fitting these data with a power curve. And this study used data obtained from floodmark checkup as well as HEC-RAS model to analyze the hydrodynamic characteristics of monitoring sites. Reach-averaged hydraulic parameters for the supply reach were calculated from the small area's HEC-RAS model for Idong stream, and a HEC-RAS model used to analyze hydraulics for a period in 2007, after the stream was considered bank stabilization.

새로운 HVT 성장방법을 이용한 CIGS 결정성장

이강석,전헌수,이아름,정세교,배선민,조동완,옥진은,김경화,양민,이삼녕,안형수,배종성,하홍주,Lee, Gang-Seok,Jeon, Hun-Soo,Lee, Ah-Reum,Jung, Se-Gyo,Bae, Seon-Min,Jo, Dong-Wan,Ok, Jin-Eun,Kim, Kyung-Hwa,Yang, Min,Yi, Sam-Nyeong,Ahn, Hyung-Soo 한국결정성장학회 2010 한국결정성장학회지 Vol.20 No.3

높은 광흡수 계수를$(1{\times}10^5cm^{-1})$ 가지는 CIGS는 Ga의 비율에 따라서 밴드갭을 조절할 수 있다는 장점을 지니고 있다. CIGS의 밴드갭은 Ga의 비율에 따라 $CuInSe_2$(Eg: 1.0 eV)에서 $CuGaSe_2$(Eg: 1.68 eV)까지의 범위에 존재하며, 태양전지에 서 이상적인 fill factor 모양을 가지도록 Ga의 비율을 높게 조성한다. CIGS 흡수층을 제작하는 방법에는 co-evaporator 방식이 가장 널리 사용되며 연구되고 있다. 이에 본 연구에서는 수평 형태의 hydride vapor transport (HVT)법을 고안하여 CIGS 나노 구조 및 에피성장을 시도하였다. HVT법은 $N_2$ 분위기에서 원료부의 CIGS 혼합물을 HCl과 반응시켜 염화물 기체상태로 변환 후 growth zone까지 이동하여 성장을 하는 방식이다. 성장기판은 c-$Al_2O_3$ 기판과 u-GaN을 사용하였다. 성장 후 field emission scanning electron microscopy(FE-SEM)과 energy dispersive spectrometer(EDS)를 이용하여 관찰하였다. The Cu$(In_{1-x}Ga_x)Se_2$ is the absorber material for thin film solar cell with high absorption coefficient of $1{\times}10^5cm^{-1}$. In the case of CIGS, the movable energy band gap from $CuInSe_2$ (1.00 eV) to $CuGaSe_2$ (1.68 eV) can be acquired while controlling Ga contain ratio. Generally, the co-evaporator method have used for development and fabrication of the CIGS absorption layer. However, this method should need many steps and lengthy deposition time with high temperature. For these reasons, in this paper, a new growth method of CIGS layer was attempted to hydride vapor transport (HVT) method. The CIGS mixed-source material reacted for HCl gas in the source zone was deposited on the substrate after transporting to growth zone. c-plane $Al_2O_3$ and undoped GaN were used as substrates for growth. The characteristics of grown samples were measured from SEM and EDS.

꽃게 ( Portunus trituberculatus ) Hemocyanin 의 정제 및 특성에 관하여

이강석,김상복,이정호 ( Kang Suk Lee,Sang Bog Kim,Jung Ho Lee ) 생화학분자생물학회 1985 BMB Reports Vol.18 No.2

The hemocyanin from the hemolymph of crab, Portunus trituberculatus which belong to crustacean was purified by a single step of ion-exchange column chromatography after dialysis and ultracentrifugation. The purified hemocyanin was revealed a high degree of polymorphism after analyzed it by Davis-polyacrylamide gel electrophoresis, the peroxidase activity, and copper staining method. On the other hand, the denatured hemocyanin was appeared to be homogeneous polypeptide by SDS-PAGE, and the approximate molecular weight was estimated to be 70,000. It was found that the purified hemocyanin was a glycoprotein in nature that contained 2 males of copper/l mole of hemocyanin, and it was estimated that their contents in normal body fluid were approximately 46%.

A New Discrete Size Optimization Method for Structures Using Harmony Search Heuristic Algorithm

이강석,Lee, Gang-Seok Computational Structural Engineering Institute of 2013 전산구조공학 Vol.26 No.1

MANET에서 악의적인 노드의 안전하고 효율적인 검출 방안

이강석,최종오,지종복,송주석,Lee KangSeok,Choi JongOh,Ji JongBok,Song JooSeok 한국정보처리학회 2005 정보처리학회논문지 C : 정보통신,정보보안 Vol.12 No.5

최근 MANET에서의 연구는 보안을 고려한 라우팅 서비스에 주목되어 왔으나 기존에 제시되었던 MANET에서의 악의적인 노드를 식별하는 방안들은 거짓 신고하는 악의적인 노드가 있을 때에는 이를 적절히 식별하고 제거하지 못하는 문제점이 있었다. 따라서 본 논문에서는 신고자와 혐의자 목록으로 구성되는 신고 메시지와 신고 테이블을 이용하여 경로 설정단계에서는 정상적으로 동작하지만 데이터 전달 과정에서는 데이터를 버리거나 내용을 변경시키는 행위, 또는 다른 노드를 거짓으로 신고하는 등의 악의적인 노드를 식별하는 효율적인 방안을 제안한다. 제안하는 방안은 DSR 과 AODV에 모두 적용 가능하다. 또한 성능분석을 위해 AODV와 제안된 알고리즘과 비교 분석하여 제안된 알고리즘이 평균 분실률 및 전송량 측면에서 현격한 성능차이를 있음을 보였다. Lately, the MANET research has focused on providing routing services with security and previous schemes have been proposed for detecting malicious nodes in a MANET. However, they still include some problems which malicious nodes cannot be found when they falsely report other nodes as malicious. Accordingly, we propose a novel and efficient scheme for detecting malicious nodes using report messages and a report table which is consisted of node ID both for suspecting and reporting when the malicious nodes behave normally during the route discovery, but the other hand they drop and modify packets, or falsely report other nodes as malicious during the data transmission. Our proposed scheme is applicable to not only DSR but aiso AODV. And we provide some simulation results of our proposed scheme by comparing general AODV with our proposed scheme. Simulation results show that our Proposed scheme outperforms general AODV in terms of average packet loss ratio and packet delivery ratio.

광합성 세균 Rhodobacter capsulata 에 의한 우라늄 흡착

이강석,김진규,김인규,박효국,이정호 ( Kang Suk Lee,Jin Kyu Kim,In Gyu Kim,Hyo Kook Park,Jeong Ho Lee ) 한국하천호수학회 1990 생태와 환경 Vol.23 No.4

Aqueous waste effluents from nuclear fuel processing operations may contain trace quantities of heavy metals such as uranium, Conventional treatment of waste waters may be ineffective or expensive when uranium concentrations in the waste water must be reduced down to 1 ㎍/㎖ or less. The ability of some microorganisms to uptake or adsorb dissolved heavy metals offers an alternative method for waste treatment. The adsorption of uranium by Rhodobacter capsulata DSM 1710, a strain of photosynthetic bacteria, was examined to identify factors that might affect a process for the removal of uranium from aqueous solution. The optimal pH for uranium adsorption was 4.5. Temperature had little or no effect on the process since more than 95% of dissoved uranium was adsorbed to the bacterial biomass within 10 minutes after mixing of cell biomass at 25, 30, and 40 ℃, all the same. Maximum capacity of uranium adsorption by R. capsulata DSM 1710 was equivalent to 1/4 of the dry cell mass (248 ㎍ U/㎎-dry biomass), the highest among the reported so far.

Studies on Histones from Sracoma 180 Ascites Tumor Cells. Biosynthesis and Phosphorylation

이강석,Lee, Kang-Suk 생화학분자생물학회 1971 한국생화학회지 Vol.4 No.2

1. Histone fractions, f1, f2b, f2a2, f3 and f2a1 were isolated from Sarcoma 180 ascites tumor cells and characterized by acrylamide disc electrophoresis, phosphorylation in vitro and amino acid analysis. 2. The rate of incorporation in vivo of L-Iysine-$^{14}C$ into different histone fractions isolated from tumor cells and tumor-bearing liver of mice has been determined for the study of biosynthesis. The fraction f2b from the tumor cells showed the highest incorporation rate, whereas the fraction f2a2 exhibited the lowest. No marked differences in the incorporation rate of the lysine-$^{14}C$ into the fractions f3, fl and f2a1 were observed 3. In the experiments with tumor-bearing mouse liver, the rate of lysine-$^{14}C$ into the histone fractions fl, f2a1, f2a2 and f3 was very similar to each other. On the other hand, the rate of incorporation of lysine-$^{14}C$ into the fraction f2b was approximately twice as high as that into other fractions. 4. The incorporation rate of lysine-$^{14}C$ into histone fractions isolated from the tumor cells was higher (approximately 1.5 times) than that into liver histone fractions. 5. Amino acid composition of the whole histone from the tumor cells is very similar to the published values for calf liver and kidney and rat liver. It is also similar to that for calf thymus except for the lower content of basic amino acids and lower ratio of basic residues. The whole histone fractions isolated from the tumor cells contained much less proline and methionine and much more glutamic acid, as compared with that isolated from others. Amino acid composition of the whole histone isolated from tumor-bearing liver of mice showed higher content of basic amino acids and lower content of acidic residues. 6. The relative amounts of incorporation in vitro of $^{32}P$ into different histone fractions from cells have been determined. The incorporation of $^{32}P$ into histone fractions f2b was the greatest, while almost no radioactivities were observed in the fractions f2a1 and f2a2. The incorporation of the radioisotopes into remaining fractions was variable from one fraction to another, the incorporation rate into the fraction fl being higher than that into the f3 fraction. 7. Evidence was obtained confirming the presence of phosphoserine in histone fractions f2b, f1 and f3 from cells. It was shown that a greater amount of $^{32}P$ was incorporated into the fraction f2b. being present in the form of phosphoserine in the proteins. 1. Sarcoma 180 ascites tumor cells에서 histone 분획 f1, f2b, f2a2, f3 및 f2a1을 각각 추출 정제하여 각 분획을 acrylamide disc electrophoresis. $^{32}P$를 사용하여 in vitro에서 phosphorylation 및 amino 산 조성을 관찰하여 이 물질들의 성상을 밝혔다. 2. 마우스의 복수암 세포 및 간에 lysine-$^{14}C$을 in vivo에서 incorporate 시켜 histone의 생합성을 각 분획별로 비교 관찰하였다. 복수암 세포 histone 에서는 lysine-$^{14}C$이 f2b 분획에 가장 많이 incorporate 된 반면 f2a2가 가장 적었다. 분획 f3, f1 및 f2a1에는 차이가 없이 비슷하였다. 3. 복수암이 이식된 마우스의 간 histone에 lysine-$^{14}C$의 incorporate 된 비율은 분획 f2b가 다른 분획 보다 2배 높았고 분획 f1, f2a1, f2a2 및 f3는 거의 비슷하였다. 4. Lysine-$^{14}C$의 incorporation은 복수암 histone 분획들이 간 histone 분획 보다 1.5 배나 더 많이 일어났다. 5. 복수암 세포 histone의 amino 산 조성은 이미 보고된 소의 간, 신장 및 흰쥐의 간 histone과 비슷하였다. 또 소 흉선 histone의 amino 산 조성에 비하면 염기성 amino 산 함량이 낮은 것과 산성 amino 산에 대한 염기성 amino 산의 비율이 낮은 점을 제외하고는 유사하였다. 복수암 세포의 총 histone을 기타 정상조직 histone과 비교하면 proline과 methionine이 대단히 적었고 glutamic acid의 함량이 더 많았다. 복수암을 이식한 마우스 간의 총 histone 의 amino 산 조성은 정상조직과 비교하면 염기성 amino 산 함량이 높았으며 산성 amino 산 함량이 낮었다. 6. 복수암 세포의 핵을 in vitro 에서 $^{32}P$와 함께 incubate 하고 histone 각 분획에 incorporate 되는 비율을 관찰하였다. Histone 분획 f2b에 가장 많이 $^{32}P$가 incorporate 된 반면 분획 f2a1 및 f2a2에는 거의 incorporate 가 일어나지 않았다. 기타 분획에 incorporate 되는 비율은 큰 차이를 나타냈다. 즉 분획 f1이 f3 보다 높은 방사능을 나타냈다. 7. Phosphoserine을 복수암 세포의 histone 분획 f2b, f1 및 f3에서 분리 확인하였으며 이런 점으로 미루어 분획 f2b 단백질 내에 phosphoserine의 형태로 많은 량의 $^{32}P$가 incorporate 됨을 알 수 있었다.

꽃게 (Portunus trituberculatus) Hemocyanin의 정제 및 특성에 관하여

이강석,김상복,이정호,Lee, Kang-Suk,Kim, Sang-Bog,Lee, Jung-Ho 생화학분자생물학회 1985 한국생화학회지 Vol.18 No.2

꽃게 (P. trituberculatus) hemolymph를 채취한 후 원심분리 및 DEAE-Sephadex A-50 column chromatgraphy를 행하여 hemocyanin을 정제하였다. 정제된 hemocyanin은 단일 polypeptide로 이루어져 있었으며 monomer의 분자량은 약 70,000으로 추정 되었다. 또한 꽃게 hemolymph 단백질중 hemocyanin의 함량은 46%, Cu는 단일 polypeptide 당 2 mole, 그리고 당 함량은 단백질 mg 당 $10\;{\mu}g$ 이었다. 한편 정제된 hemocyanin은 Ca등 2가 이온을 가하지 않고 pH 5.7~8.9인 상태에서 mono, di, tri, tetra, pentamer등 다양한 polymorphism을 나타내었다. The hemocyanin from the hemolymph of crab, Portunus trituberculatus which belong to crustacean was purified by a single step of ion-exchange column chromatography after dialysis and ultracentrifugation. The purified hemocyanin was revealed a high degree of polymorphism after analyzed it by Davis-polyacrylamide gel electrophoresis, the peroxidase activity, and copper staining method. On the other hand, the denatured hemocyanin was appeared to be homogeneous polypeptide by SDS-PAGE, and the approximate molecular weight was estimated to be 70,000. It was found that the purified hemocyanin was a glycoprotein in nature that contained 2 moles of copper/l mole of hemocyanin, and it was estimated that their contents in normal body fluid were approximately 46%.