Hot Wall Epitaxy 법에 의한 CdIn_2S_4 단결정 박막의 성장과 광전류 특성

이상열,홍광준,박진성 한국센서학회 2002 센서학회지 Vol.11 No.5

수평 전기로에서 Cdln_2S_4 다결정을 합성하여 HWE(Hot Wall Epitaxy)방법으로 Cdln_2S_4 단결정 박막을 반절연성 GaAs (100)기판에 성장시켰다. Cdln_2S_4 단결정 박막의 성장 조건은 증발원의 온도 630 ℃, 기판의 온도 420 ℃ 였고 성장 속도는 0.5 ㎛/hr였다. Cdln_2S_4 단결정 박막의 결정성의 조사에서 10 K에서 광발광(photoluminescence) 스펙트럼이 463.9 nm (2.6726eV)에서 exciton emission 스펙트럼이 가장 강하게 나타났으며, 또한 이중 결정 X-선 요동 곡선(DCRC)의 반폭치(FWHM)도 127 arcsec로 가장 작아 최적 성장 조건임을 알 수 있었다. Hall효과는 van der Pauw 방법에 의해 측정되었으며, 온도에 의존하는 운반자 농도와 이동도는 293K에서 각각 9.01 × 10 exp (16) /cm^3, 219 cm^2/V·s였다. Cdln_2S_4 /Sl(Semi-Insulated) GaAs(100) 단결정 박막의 광흡수와 광전류 spectra를 293K에서 10K까지 측정하였다. 광흡수 스펙트럼으로부터 band gap E_g(T)는 Varshni 공식에 따라 계산한 결과 2.7116eV - (7.74x10 exp (-4)eV/K)T^2/(T+434K)이었으며 광전류 스펙트럼으로부터 Hamilton matrix(Hopfield quasicubic mode)법으로 계산한 결과 crystal field splitting Δcr값이 0.1291 eV이며 spin-orbit Δso값은 0.0248 eV임을 확인하였다. 10K일 때 광전류 봉우리들은 n = 1일때 A_1-B_1-와 C_l-exciton 봉우리임을 알았다. A stoichiometric mixture of evaporating materials for Cdln_2S_4 single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, Cdln_2S_4 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE)system. The source and substrate temperatures were 630℃ and 420℃, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of Cdln_2S_4 single crystal thin films measured with Hall effect by van der Pauw method are 9.01×10 exp (l6) cm^-3 and 219 cm^2/V·s at 293 K, respectively. The temperature dependence of the energy band gap of the Cdln_2S_4 obtained from the absorption spectra was well described by the Varshni's relation, E_g(T) = 2.7116 eV - (7.74× 10 exp (-4)eV)T^2/(T+ 434). The crystal field and the spin-orbit splitting energies for the valence band of the Cdln_2S_4 have been estimated to be 0.1291 eV and 0.0248 eV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the Δso definitely exists in the Γ_5 states of the valence band of the AgInS_2/GaAs epilayer. The three photocurrent peaks observed at 10K areascribed to the A_l-, B_l-, and Cl-exciton peaks for n = 1.

위암종과 Epstein-Barr 바이러스와의 연관성에 대한 연구

심광용,김호영,김효열,백순구,권상옥,조미연,이창훈,이종인 건국대학교 의과학연구소 2004 건국의과학학술지 Vol.14 No.-

Objectives: Epstein-Barr virus (EBV) has been known to be linked to a spectrum of neoplastic conditions, including nasopharyngeal carcinoma, Burkitt's lymphoma, peripheral T-cell lymphoma and Hodgkin's disease. This study aims to investigate the association of EBV with gastric carcinoma in Korea. Methods: Fifty-three cases of gastric adenocarcinoma were studied for evidence of EBV infection by EBV-encoded small RNA (EBER) in situ hybridization (ISH) on the paraffin sections and amplifying the EBV genome encoding envelop glycoprotein (gp220) with polymerase chain reaction (PCR) in fresh gastric cancer specimens. Results: EBER was detected in 7 (13.2%) of 53 gastric carcinomas and all cases were male. In 6 (85.7%) of 7 EBER-positive cases, the tumors were located in the upper and middle part of the stomach. EBER ISH study showed strong positivity in all the tumor cells, but negativity in surrouning lymphocytes, stromal cells and normal gastric mucosa. DNA PCR was positive in 23 (43.4%) of 53 gastric carcinomas, including all of 7 EBER-positive cases. Conclusion: We could observe some association of EBV with gastric carcinoma, and our findings about the charateristics of EBV-positive gastric cancers involving sex, site and histological type are similar to those in Japan. However, EBV-positive rate of gastric cancer is higher than in Japan and lower than in Western countries. Further studies to elucidate oncogenic mechanism of EBV in gastric cancer should be performed.

C.V.D. 방법에 의한 Cd_0.78Zn_0.22 S박막 성장과 광전기적 특성연구

유상하,이상렬,홍광준,서상석,김혜숙,전승룡,윤은희,문종대 조선대학교 기초과학연구소 1993 自然科學硏究 Vol.16 No.1

We had grown Cd_0.78Zn_0.22S polycrystal thin films on slide substrate using chemical vapour deposition(CVD) method. We measured X-ray diffraction patterns in order to study Cd_0.78Zn_0.22S polycrystal structure. We studied its band gap using transmission curves and photocurrent and also analyzed photoluminescence using configurational coordinate model. We measured Hall effect·on this sample by Van der Pauw method and studied on carrier density and mobility depending on temperature.

B형 간염 동반 원발성 간암 환자에서의 CYP2D6와 NAT2 다형현상에 관한 연구

신동일,이광수,최연남,황기은,조율희 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.2

The CYP2D6 and N-acetyltransferase (NAT2) are polymorphic enzymes which are expressed in the hepatocyte in a genotype-determined manner. CYP2D6 and NAT2 are known to be involved in the inactivation and activation of various mutagens and carcinogens, respectively. The activities of the two enzyme systems are associated with the genetic susceptibility of many human cancers. This study was performed to determine the genotype frequencies of the two enzyme systems in primary hepatocellular carcinoma patients and healthy controls. One hundred healthy controls and 55 liver cancer patients were analyzed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). The results are as followings:1. In the healthy controls, CYP2D6 wild type allele frequency was 0.985 and CYP2D6^*4 frequency was 0.015, and no CYP2D6 poor-metabolizer was detected. No significant differences were found in hepatocellular carcinoma patient group. 2. Frequencies of F, S1, S2 and S3 alleles of NAT2 system were 0.725, 0.01, 0.14 and 0.125 in controls, respectively. The genotype frequencies were found to be 0.91 of rapid acetylator and 0.09 of slow acetylator. No significant differences were found in hepatocellular carcinoma patient group. 3. These results suggest that the distribution of CYP2D6 and NAT2 polymorphisms is very unique in Korean populations characterized by extremely low frequency of CYP2D6 poor-metabolizer and NAT2 slow acetylator. CYP2D6 and NAT2 polymorphisms seemed not to play an important role in the hepatic carcinogenesis in Korean population.

Comparative Genomic Hybridization 기법을 이용한 한국인 원발성 간세포암에서의 염색체 변화에 대한 연구

박훤겸,정풍만,이광수,조율희 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

Comparative genomic hybridization(CGH) technique is one of the screening tests for DNA sequence copy number changes(losses, deletions, gains, amplifications) in tumor genomes. DNA changes in 23 hepatocellular carcinomas(HCC) associated with hepatitis B virus(HBV) were analyzed by CGH technique. Eighteen of the 23 cases showed genetic alterations. The remaining 5 cases showed no detectagble aberration. The losses of chromosome regions 17p(74%), 4q (57%), 16p (52%), 16q (48%), 8p (43%) and 13q (43%) were detected in the order of decreasing frequency. In cases of multiple losses of chromosomes, a combination of 17p,16p,16q,4q, and 8p losses was found in 5 cases (30%). On the other hand, chromosomal gains occurred on 1q (65%), 8q (52%), 20p (48%) and 20q (43%) in the order of decreasing frequency. And the simultaneous genomic gains of these 4 chromosomes were found in 9 cases (40%). Moreover, the combination of 5 genomic losses (17p, 16p, 16q, 4q, & 8p) and 4 genomic gains (1q, 8q, 20p, & 20q) was observed in 4 case s(23%). The pattern of chromosomal gains and losses in HCC with hepatitis B in Korean patients is very complex and involves virtually every site in the genome. This indicated a high genomic instability. This could possibly be explained either as the result of random chromosomal changes during early development of tumor, or as the highly variable and random pattern of integration of HBV in the HCC. The hepatocarcinogenesis may be the result of cumulative effocts rather than those orders of occurrence of those genomic changes. The sites of cellular DNA at which HBV integrates frequently undergo rearrangements, resulting in translocations, inverted duplications, deletions, and possibly recombinational events. But, CGH only detects changes of chromosomal copy number but could not identify translocations, inversions, and other aberrations of chromosome. The chromosomal analysis of HCC with HBV in Korean patients by CGH technique confirms the presence of complex and sporadic, but nonrandom genetic changes in the chromosome. In the future, more detailed oncogenic study could be carried out on the chromosomes which showed abnormal aberrations through this study.

n-CdS_(0.46)Se_(0.54)/p-Cu_92-x)S_(0.46)Se_(0.54) 이종접합 태양전지의 제작과 그 특성에 관한 연구

유상하,최승평,이상열,홍광준,서상석,김혜숙,전승룡,윤은희,문종대,신영진,정태수,신현길,김택성,유기수 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

승화방법에 의해 CdS_0.46Se_0.54 단결정을 성장하여 결정구조를 조사하고, Van der Pauw 방법으로 Hall effect를 측정하여 carrier density의 온도 의존성과 mobility의 온도 의존성을 조사하였다. 성장된 CdS_0.46Se_0.54 단결정을 치환반응하여 n-CdS_0.46Se_0.54/p-Cu_2-xS_0.46Se_0.54 이종접합 태양전지를 제작하였다. Spectral response, 전류-전압특성 및 전력변환 효율을 조사하여 그 결과로부터 개방전압은 0.48V, 단락 전류 밀도는 21mA/㎠, fill factor와 전력변환효율은 각각 0.75와 9.5%를 얻었다. CdS_0.46Se_0.54 single crystal was grown by a sublimation method. The crystal structure and the temperature dependence of carrier density and mobility of CdS_0.46Se_0.54 single crystal were studied. Heterojunction solar cells on n-CdS_0.46Se_0.54/p-Cu_2-xS_0.46Se_0.54 were fabricated by the substitution reaction. The spectral response, the J-U characteristics and the conversion efficiency of the n-CdS_0.46Se_0.54/p-Cu_2-xS_0.46Se_0.54 heterojunction solar cells were studied. The open-cricuit voltage, short-circuit density, fill factor and conversion efficiency of n-CdS_0.46Se_0.54/p-Cu_2-xS_0.46Se_0.54 heterojunction solar cells under 80mW/㎠ illumination were found to be 0.48V, 21mA/㎠, 0.75 and 9.5%, respectively.

TGF-β-dependent Cell Growth Arrest and Apoptosis

Lee, Kwang-Youl,Bae, Suk-Chul Korean Society for Biochemistry and Molecular Biol 2002 Journal of biochemistry and molecular biology Vol.35 No.1

Overexpression, Purification and Truncation Analysis of RmlC Protein of Mycobacterium tuberculosis

Lee, Jong-Seok,Lee, Tae-Yoon,Park, Jae-Ho,Kim, Jong-Sun,Lee, Tae-Jin,Lee, Jai-Youl,Kim, Sung-Kwang The Korea Society for Microbiology 2000 大韓微生物學會誌 Vol.35 No.4

dTDP-rhamnose provides L-rhamnose to the bridge-like structure between mycolyl arabinogalactan and peptidoglycan of the mycobacterial cell wall. dTDP-rhamnose is composed of glucose-l-phosphate and dTTP by four enzymes encoded by rmlA-D. To determine the region(s) of RmlC protein essential for its dTDP-4-keto-6-deoxyglucose epimerase activity, we overexpressed both whole (202 amino acids) and three different truncated (N-terminal 106 or 150 or C-terminal 97 amino acids) RmlC proteins of Mycobacterium tuberculosis. The RmlC enzyme activity in the soluble lysates of ${\Delta}rmlC$ E. coli strain $S{\Phi}874$ (DE3 PlysS) expressing the wild type or truncated rmlC genes was initially analyzed by three sequential reactions from dTDP-glucose to dTDP-rhamnose in the presence of purified RmlB and RmlD. All three soluble lysates containing the truncated RmlC proteins showed no enzyme activity, while that containing the wild type RmlC was active. This wild type RmlC was then overexpressed and purified. The incubation of the purified RmlC enzyme so obtained with dTDP-4-keto-6-deoxyglucose resulted in the conversion of dTDP-4-keto-rhamnose. The results show that the truncated regions of the RmlC protein are important for the RmlC enzyme activity in M. tuberculosis.

Breeding of Korean Ginseng ( Panax ginseng C. A. Meyer )

Kwang Tae Choi,Woo Saeng Kwon,Sung Sik Lee,Jang Ho Lee,Youl Young Chung,Je Yong Kang,Myong Gu Lee 고려인삼학회 1998 International Symposium on Ginseng Vol.- No.-

Model Ortaisms in Development and Diseases : O-Linked N-acetylglucosamine modification regulates dauer entry in Caenorhabditis elegans

( Kwang Youl Kim ),( Jee Yong Lee ),( Ji Hyun Lee ),( Young Ki Paik ) 한국생화학분자생물학회 (구 한국생화학회) 2008 생화학분자생물학회 춘계학술발표논문집 Vol.2008 No.-