실리콘 박막 태양전지의 고효율화 기술시장 동향과 향후 전략

비매

유기 태양전지의 기술현황 및 시장동향

비매품/무

이질적 시계열 유전자 데이터의 스트레스 연관 유전자 및 스트레스 예측 기법

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 컴퓨터공학부, 2018. 8. 김 선.As gene expressions which contains data of big dimension begin to be formed, the necessity of integrated analysis of time series gene expression data is emerged. However, analyzing gene expression data is a new time series analysis problem that is not addressed in existing computer science as there are not only much time series data with few time points though it has many features but also its heterogeneous time series analysis problem in which the measurement points and experiment conditions are different with data of disorganized form, such as raw text and expression data of mixed time series. In this study, I introduce feature embedding method with such heterogeneous time series data in form of minimizing data loss, and introduce logical relevance layer which indicates stress-gene correlation weight which is learned with cross-entropy and group effect. This layer also used in stress prediction model with logical filter layer on top of this model to get output in logical probability, and this layer is learned with CMCL (Confident Multiple Choice Learning) loss to prevent parameter overfitting. This model revealed many Gene Ontology related to given stress with high stress-gene correlation weight. Also, to find out whether the genes which are only responding with specific stress are ranked higher, I compared gene rank for each stress of ordinary Fisher's method with my method, and I found many genes which has multiple GO term, which means correlated to multiple stimulus, are downranked in my method compared to combined limma p-value of each time series data using Fisher's method, which means this model gives high rank in genes which only respond to specific stress. Furthermore, this prediction model showed excellent performance compared to classical prediction methods like Random Forest and SVM. Therefore, this result suggests new method for selecting gene only responding to specific stress type and predicting stress using time series data with small amount of time points and replication.I. Introduction 1 1.1 Gene Expression Data 2 1.1.1 Microarray Data 2 1.1.2 Time-series Microarray Data 3 1.2 Motivation 3 1.2.1 Limitation of current biomarker detection methods 3 1.2.2 Difficulty of analyzing time-series data 4 II. Materials and Methods 6 2.1 Time series data 7 2.1.1 Definition 7 2.1.2 Dataset 8 2.1.3 Feature embedding 8 2.1.4 Limma and Foldchange 9 2.2 Stress-related gene detection model 11 2.2.1 Logical correlation layer 11 2.2.2 Group effect 12 2.3 Stress prediction model 13 2.3.1 Transposed logistic correlation layer 13 2.3.2 Normalizing 14 2.3.3 Logistic filter 15 2.3.4 CMCL loss function 15 2.4 Existing methods for performance comparison 16 2.4.1 Fishers method 16 2.4.2 Random Forest and SVM 17 III. Experiments and Results 20 3.1 Analysis of high stress-responsive genes 20 3.2 Gene rank comparsion with Fishers method 23 3.3 Stress type prediction 26 IV. Discussions 29 References 31 한글 초록 33Maste

Changes of 5-hydroxytryptamine release by different glucose concentrations from hippocampal slices exposed to hypoxia

의학과/석사[한글] 노의 허혈시에는 여러 중추신경 전달물질의 변동이 관찰된다. 허혈시에 유도되는 저산소 상태 및 포도당 농도의 변동 모두가 5-hydroxytrptamine(5-HT)을 포함한 아민계 신경 전달물질의 유리에 영향을 주는 인자로 작용할 수 있다. 본 연구에서는 해마의 조직 절편 에서의 5-HT 유리에 미치는 저산소 상태 및 포도당 농도 변동의 상호연관 관계를 알아보고자 하였다. 이를 위하여 여러 농도의 포도당이 처지된 영약액군(0 mM : 포도당 배제군, 1,2 및 5 mM : 저농도 포도당군, 10 mM : 정상농도 포도당군, 20mM : 고농도 포도당군으로 나눔)에서 저산소 10분 또는 20분 노출에 따라 흰쥐(Sprague-Dawley계)의 해마 절편으로부터 유리되는 [3**H] 5-HT의 유리를 관찰하였다. 실험결과를 요약하면 다음과 같다. 1. 정상농도 포도당군의 경우 전 실험기간 옛 지속적인 5-HT 유리의 감소가 나타났다. 저산소 노출시에는 이러한 5-HT 유리 감소가 더욱 심해지는 양상을 보였으나 산소 재 공급후에는 5-HT의 반동성 유리증가가 관찰되었다. 2. 저농도 포도당군에서는 포도당 농도가 낮은 영양액일수록, 대조군(저산소 비노출군) 및 10분 또는 20분 저산소 노출군 사이의 5-HT 유리감소 정도의 차이가 줄어드는 경향을 보였으나, 유리감소 양상은 정상농도 포도당군과 동일하였고, 저산소 노출시간에 따른 유리 양상의 변동에도 정상농도 포도당군과의 유의성 있는 차이는 보이지 않았다. 3. 저산소 노출에 의한 유리감소 양상은 고농도 포도당군의 경우에도 차이가 없었으며, 감소 정도는 정상농도 혹은 저농도 포도당군과 유사한 수준에 해당하였다. 4. 포도당 배제군의 경우, 실험기간동안 지속적으로 5-HT의 유리증가가 관찰되었으며 또한 이러한 유리증가는 저산소 노출기간 중에 더욱 크게 나타나 포도당 처리군의 경우와 반대의 유리 양상을 나타내었다. 이상의 실험결과로 보아 저산소 상태 및 포도당 농도 변동은 상호 독립적으로 해마조직으로부터 5-HT의 유리에 영향을 주며, 포도당 농도 변동의 의한 5-HT 유리는 포도당의 존재 유무에 따라 상이한 기전이 작용하고 있을 것으로 생각된다. [영문] Ischemic insult to the brain leads to alterations of neurotransmitter release in the central nervous system. Any of two factors, hypoxia and changes of glucose concentration can act as a modulating stressor affecting the release of amine neruotransmitters including 5-hydroxytryptamine (5-HT) in an ischemic environment, This study was performed to investigate the relationship between the effects of glucose concentration and the hypoxia on spontaneous 5-HT release from the rat hippocampal slices. Experimental groups were divided into 4 groups for this study : glucose-deprived group , low-glucose group (1,2 or 5 mM glucose), high-glucose group (20mM glucose), and normal-glucose group (10 mM glucose). In each group, the hippocampal slices were exposed to hypoxic insult for 10 or 20 min by replacint the oxygen-saturated medium with buffer saturated with 95% N^^2/5% CO^^2 gas mixture. Release of [3**H] 5-HT from the rat hippocampal slices was measured at every 10 min. The results are as follows. 1. In normal-glucose group, spontaneous release of 5-HT decreased gradually throughout the experiment. Hypoxic exposure for 10 or 20 min decreased the 5-HT release markedly from hippocampal slices. Rebound increase of 5-HT release was observed after recovery from hypoxia. 2. The low-glucose group showed the similar pattern of 5-HT release to normal-glucose group, although the degree of reduction in 5-HT release during hypoxic period tends to decrease. No significant difference in the pattern of 5-HT release according to the duration of hypoxic exposure was noted. 3. There was no difference in the decreasing pattern of 5-HT release by a hypoxic exposure in high-glucose group compared with those of low-and normal-glucose groups, and the level of decrease in 5-HT release was in the similar range to those of low-glucose groups. 4. In glucose0deprived group, the pattern of 5-HT release was opposite to the other groups. The spontaneous release of 5-HT was increased with time throughout the experiment. This increase of 5-HT release was exaggerated during hypoxic period and larger with longer duration of hypoxic exposure. These results give implications that the hypoxic stress and the hypo - or hyperglycemic one may influence on the 5-HT release from hippocampal slices independently and that in the absence of glucose, the 5-HT may be released by a mechanism different from that in the presence of glucose.restrictio

(A) Legal Study on The Governance Structure of Korean Private Equity Fund

학위논문(석사) --서울대학교 대학원 :법학과,2010.2.Maste

Field emission of carbon nanotubes fabricated on porous anodic aluminum oxide templates

Thesis(master`s)--서울대학교 대학원 :화학부 물리화학전공,2004.Maste

실리콘 박막 태양전지의 광포집 특성 강화를 위한 신규 투명 전도막과 반사방지막의 제안 및 제작

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2013. 2. 한민구.Solar cells have received a lot of attention as generating electric energy technology among various renewable energy sources. Silicon (Si) thin film solar cells are promising due to their potentials of low cost and large area manufacture. Light confinement into photoactive Si layers is one of the essential techniques to increase conversion efficiency with decreasing Si thickness. In this thesis, various approaches about transparent conductive oxide (TCO) and anti-reflection coating (ARC) was introduced in order to enhance the light trapping in the Si thin film solar cells. As for the TCO, important factors to determine texture-etching profiles of Al-doped ZnO (AZO) was investigated by controlling substrate temperature and sputter pressure. It was thought that crystallinity and compactness of AZO films significantly affect the surface morphology of textured AZO films. In order to obtain highly light scattering capability of AZO, I have focused on an improvement of the crystallinity of AZO films. Oxygen controlled seed layer and ITO buffer were employed before the bulk AZO deposition to enhance the polycrystalline growth of AZO films. The improved crystallinity by those techniques allowed for better optoelectronic properties of AZO films. Reliability of TCOs resistivity is one of the critical issues for maintaining solar cell performance. In this work, Ga- and Al- codoped ZnO (GAZO) and B- and Al- codoped ZnO (BAZO) films were suggested and they exhibited pronounced stable resistivity compared to the widely used AZO film under thermal annealing in atmospheric air and H2O vapor ambient. In a field of the ARC, optoelectronic properties of TiO2 ARC was systematically investigated and optimized. Also, novel GaN ARC was proposed at the TCO/Si interface and the promising results for replacing the TiO2/ZnO bilayer ARC by the GaN was demonstrated. In addition to those ARC, I proposed Al2O3 and MgO ARC at glass/TCO interface to further improve light trapping at front interfaces. Microcrystalline Si (µc-Si:H) solar cells employing those ARC exhibited decreased cell reflectance and improved quantum efficiency. The light trapping was maximized by employing glass texture in combination with the proposed TCO and ARC. The light trapping capability was enhanced through texture-etching of air/glass interface, which demonstrated the improvement of light absorption without sacrificing Voc and FF. Those approaches above indicates that light trapping at front interfaces can provide the promising results for improving the absorption in Si thin film solar cells.Abstract i List of Tables vii List of Figures viii Chapter 1. introduction 1 1.1 Recent trend of silicon photovoltaic 1 1.2 Dissertation organization 11 Chapter 2. Review of silicon thin film solar cells 13 2.1 Silicon thin film solar cells 13 2.2 Transparent conductive oxide for light trapping 16 2.3 Anti-reflection coating for light trapping 23 Chapter 3. Transparent Conductive Oxide (TCO) for Light trapping 26 3.1 Overview 26 3.2 Magnetron Sputtering for TCO deposition 29 3.3 Characterization of surface-textured Al-doped ZnO (AZO) for light trapping 31 3.3.1 Motivation 31 3.3.2 Surface texture of AZO: effect of deposition temperature 32 3.3.3 Surface texture of AZO: effect of deposition pressure 44 3.3.4 Conclusion 48 3.4 Buffer layer techniques for high quality AZO 49 3.4.1 Oxygen controlled bilayer AZO 49 3.4.2. ITO/AZO bilayer 67 3.4.3. Microcrystalline Si solar cells with the proposed TCO 79 Chapter 4. Advanced TCO for high electrical stability 82 4.1 Overview 82 4.2 Advanced TCO: Ga- and Al- codoped ZnO (GAZO) 84 4.2.1 Motivation 84 4.2.2 Experimental details 84 4.2.3 The structural characteristics of GAZO Films 86 4.2.4 The electrical characteristics of GAZO Films 96 4.2.5 The optical characteristics of GAZO Films 99 4.2.6 The electrical stability of GAZO Films 101 4.2.7 Conclusion 104 4.3 Advanced TCO: B- and Al- codoped ZnO (BAZO) 105 4.3.1 Motivation 105 4.3.2 Experimental details 106 4.3.3 Structural property of BAZO films 107 4.3.4 Electrical property of as-deposited BAZO films 111 4.3.5 Electrical stability of BAZO films 113 4.3.6 Conclusions 122 Chapter 5. Anti-reflection coating (ARC) for light trapping 123 5.1 Overview 123 5.2 TiO2/ZnO bilayer ARC at TCO/Si interface 126 5.2.1 Motivation 126 5.2.2 Experimental details 126 5.2.3 Effect of substrate temperature on TiO2 film properties 129 5.2.4 Effect of oxygen-diluted sputtering on TiO2 film properties 137 5.2.5 a-Si:H/a-SiGe:H tandem solar cells with TiO2 ARC 144 5.2.6 Conclusions 148 5.3 GaN ARC at TCO/Si interface 149 5.3.1 Motivation 149 5.3.2 Experimental details 150 5.3.3 Thickness simulation for ARC at TCO/Si interface 152 5.3.4 Optoelectronic properties of sputtered GaN films 154 5.3.5 Microcrystalline Si solar cells with GaN ARC 159 5.3.6 Conclusions 163 5.4 Al2O3 ARC at glass/TCO interface 164 5.4.1 Motivation 164 5.4.2 Experimental details 165 5.4.3 Simulation of Al2O3 for ARC at glass/TCO interface 168 5.4.4 Experimental characterization of Al2O3 film for ARC 170 5.4.5 Microcrystalline Si solar cells with Al2O3 ARC 173 5.4.6 Conclusions 178 5.5 MgO ARC at glass/TCO interface 179 5.5.1 Motivation 179 5.5.2 Experimental details 179 5.5.3 Simulation of MgO thin film for ARC 182 5.5.4 Structural property of MgO/AZO bilayer 184 5.5.5 Electrical and optical property of MgO/AZO film 186 5.5.6 Texture-etching property of MgO/AZO film 189 5.5.7 Microcrystalline Si solar cells with MgO/AZO film 191 5.5.8 Conclusions 193 Chapter 6. Glass texture for enhanced light trapping 194 6.1 Overview 194 6.2 Glass texture by ICP RIE etcher 197 6.2.1 Effect of sputter pressure on texture-etching of glass 198 6.2.2 Effect of self-bias power on texture-etching of glass 201 6.3 Glass texture at air/glass interface 203 6.4 Light trapping effect of the texture at air/glass interface 209 6.5 Conclusion 215 Chapter 7. Summary 216 Bibliography 220 Abstract (korean) 236Docto

Simultaneous changes of behavioral and immune parameters after repeated exposure to moderate hypoxia in mice

의학과/박사[한글] 개체가 스트레스 환경에 노출되면 적절한 적응기전을 통하여 항상성을 유지한다. 이러한 적응과정에는 행동의 변화 뿐 아니라 신경계, 내분비계, 면역계 등 여러 기능계가 관여함이 알려져 있으며 기능계들 사이에 통합적인 연관성을 가지고 반응한다는 사실이 밝혀지고 있다. 스트레스에 대한 개체의 적응과정에서 나타나는 기능계 활성 변동은 스트레스에 대한 감수성 뿐 아니라 스트레스 자극의 강도, 자극 시간, 자극이 가해지는 방법에 따라 기능 변동의 양상이 달라질 것으로 생각된다. 본 연구에서는 스트레스에 의한 행동 및 기능계 변동의 상호 연관성 및 스트레스 자극의 강도에 따른 개체의 적응 반응을 통합적 차원에서 알아보고자 하였다. 저산소 스트레스를 자극원으로 하여 마우스에서 자극의 크기를 달리한 실험군(비처치군 : 사육장에서만 사육된 군, 환경 노출군 : 20%군, 저산소 환경 노출군 : 15%군 및 10%군)에서 저산소 자극을 매일 60분씩, 주당 5일씩 8주간 반복하여 노출시킨 후 행동검사 및 면역기능 검사를 시행하였다. 운동 조화 능력을 검사하는 Rota-rod 검사, 비조건화 행동 검사인 탐색행동 검사, 조건화 행동 검사인 능동적 조건회피 학습 검사를 행하였다. 면역기능 검사로서 유세포 분석기를 이용한 비장세포의 아군 분포 검사, 간접효소면역 측정법을 이용한 항원특이항체 생성 검사, (3)**Hthymidine incorporation을 이용한 항원 감작 비장세포 증식능 및 4시간-(51)**Cr 유리법을 이용한 자연살세포 세포독성능 검사를 시행하였다. 연구결과는 아래와 같다. 1. Rota-rod 검사에서 15%군에서 회전봉에서 떨어지지 않고 머물러 있는 시간이 다른 군들보다 길었다. 2. 탐색행동에서 15%군은 다른 군들에 비하여 활동도가 감소하였다. 3. 능동적 조건회피 학습 검사에서 15%군은 20%군과 유사한 회피반응을 보였으나,10%군은 이보다 감소된 회피반응을 나타내었다. 4. 비장세포 아군 분포에서 CD3**+, CDl9**+ 세포의 경우 각 실험군들 사이의 아군 분포변화에 유의한 차이는 보이지 않았고 CD3**+ CDl6**+ CD32**+, CD3**- CDl6**+ CD32**+ 및 CD3**+ CD4**+ 표현형을 나타내는 세포아군들의 분획율도 각 실험군들 사이에 차이가 없었다. 그러나 CD**3+CD8**+ 표현형을 가진 세포아군의 분획은 10%군에서 유의하게 감소되었다. 5. 항원특이 항체 생성은 15%군에서 IgG2a 항체의 생성이 다른 실험군보다 증가되었고 IgGl 및 IgM은 각 실험군 사이의 차이가 발견되지 않았다. 6. 항원 감작 비장세포 증식능과 자연살세포의 세포독성능은 각 실험군 사이에 유의한 차이가 없었다. 이상의 결과로 보아 저산소 환경에 개체가 반복적으로 노출되었을 때 행동과 면역반응이 연관되어 변동됨을 알 수 있었다. 즉, 고자극성 저산소 환경에의 노출은 행동을 저해하고 면역기능을 감소시키나 저자극성 저산소 환경에의 노출은 오히려 일부 행동을 호전시키고 면역기능의 일부 변수들을 증가시켰다. 따라서, 적당한 강도의 스트레스에 해당하는 저산소 자극이 신체 기능의 항진을 유도할 수 있을 것으로 생각된다. [영문] When an organism is exposed to stressful environments, it keeps its living activities by adopting an appropriate adaptive mechanism. The adaptive processes are carried out by the interaction of altered activities of several functional systems, such as nervous, endocrine, and immune systems, as well as behavioral changes. The stress response of an organism seems to be differentially manifested according to the strength of a stimulus, the duration of an exposure, and the mode of stress being given to the organism, in addition to its sensitivity to the stress. The present study aimed to elucidate the relationship between the behavioral changes and the altered function of immune system induced by an exposure to the hypoxic stress, and to study the nature of differentially manifested adaptive responses of an organism according to the strength of the stress. Four experimental groups (NH: not-handled,20%: handled, 15% or 10%: exposed to 15% or 10% O^^2 with balanced nitrogen, respectively) were exposed to different levels of hypoxia in a repeated and intermittent mode for 8 weeks, and were subjected to behavioral and immune function tests. The results were as follows. 1. A longer endurance time in Rota-rod test was noted in the 15% group. 2. During 15 min exploration, low exploratory activities were observed in the 15% group. 3. In the active avoidance tests, the number of high responder of the 10% group was significantly smaller than the 15% or the 20% group. 4. In the study of splenocyte subsets, a decreased proportion of CD3**+ CD4**+ phenotype cells was observed in the 10% group. 5. Ovalbumin-stimulated IgG2a production was increased in the 15% group, while no changes were noted in the IgG1 and IgM production. 6. Exposure to hypoxic environment did not change the antigen-stimulated splenocyte pro-liferation and natural killer cell cytotoxicity. These results show that the stress responses of the behavioral and the immune systems are changed with close relationships, and the nature of the responses is related to the strength of the stress, i.e. the high level of hypoxic stress enhances, and the low level of hypoxic stress suppresses some of the behavioral and immune parameters. Accordingly, this study indicates that an optimal level of hypoxic stress could enhance the biological function of an organism.restrictio