Tetraphenylsilane기를 포함하여 용액 공정이 가능한 고효율 인광 유기전계발광소자 단분자 호스트 물질에 관한 연구

학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2012. 8. 박수영.본 논문에서는 고효율의 인광 유기전계발광소자를 목표로 하여, 테트라페닐실란 (Tetraphenylsilane) 기를 포함함으로써 용액 공정이 가능해지는 새로운 단분자 호스트 물질군을 보고하였다. 새로이 개발된 이 물질군은 TPS series 라 명명되었으며, 9-phenyl-3-(4-(triphenylsilyl)phenyl)-carbazole (TPSPCz), 9-phenyl-3,6-bis(4-(triphenylsilyl)phenyl)-carbazole (TPS2PCz), 1,2-trans-bis(3,6-bis(4-(triphenylsilyl)phenyl)-carbazol-9-yl)cyclobutane (TPS4DCz) 등 세 물질로 구성되어 있다. 카바졸의 C3, C6 위치에 수소 대신 테트라페닐실란기가 치환됨으로써 용액 공정을 통해 균일한 필름을 얻는 것이 가능해졌다. 또한 광물리적, 필름의 형태학적 특성 연구에 기초하여, 부피가 크고 상당히 뒤틀려 있는 형태의 테트라페닐실란기가 가지는 공간상 분리 효과에 의하여 동일 평면상에 위치하는 카바졸의 엑시머 형성이 효과적으로 억제된다는 것을 증명하였다. 위 호스트 물질들은 테트라페닐실란기의 수가 증가할수록 더욱 높은 열분해 온도(전체 무게 중 약 5%의 무게가 줄어드는 온도)를 갖는 현상을 보였다 (TPSPCz : 363 °C, TPS2PCz : 424 °C, TPS4DCz : 472 °C). 특히 fac-tris(2-phenylpyridine) iridium (III) (Ir(PPy)3) 가 게스트, TPS4DCz가 호스트로 쓰인 인광 유기전계발광소자의 경우, Ir(PPy)3 가 게스트, PVK 가 호스트로 쓰인 인광 유기전계발광소자와 비교하였을 때 최대 154 % 까지 향상된 소자 성능을 보여주었다.ABSTRACT i TABLE OF CONTENTS iii LIST OF FIGURES v LIST OF SCHEMES viii LIST OF TABLES ix CHAPTER I. Introduction 1 I-1. Physics of Electrophosphorescence 1 I-2. Physics of Electrophosphorescent Light-Emitting Devices 4 I-3. Recent Progress on Solution-Processable Host Materials for Electrophosphorescent Light-Emitting Devices 9 I-4. References 13 CHAPTER II. Tetraphenylsilane Containing Solution-Processable Small-Molecular Hosts for Highly Efficient Phosphorescent Organic Light-Emitting Diodes 15 II-1. Introduction 15 II-2. Results and Discussion 19 II-3. Conclusion 41 II-4. Experimental 42 II-5. References 50 ABSTRACT IN KOREAN 55 LIST OF PRESENTATIONS 57Maste

Egocentric groups characteristics of personality and adaptation aspects according to approach and avoid motivation

학위논문(석사) --서울대학교 대학원 :심리학과,2009.2.Maste

The Formation of European Security Community: The Possiblity and Its Limits

This is a study on the possibility of the formation of the so-called European Security community and its limits. The Idea of the European integration movement was advocated by Jean Monnet for European economic development and the maintaining of peace in Europe immedately after WWII. In the same logic, Western European countries have successfully integrated into Euroepan Economic Community, but military-security perspective, they have long confronted through NATO and Warsaw Treaty Organizaion. The former is the allied institution on which western European countries depended their national defense and security and the later is the socialist alliance through which the old USSR and eastern European countries had pursued their national security. Following the collapse of the old USSR and the democratization of eastern European countries, a new European international political environment and political order have emerged. First of all, Germany was reunified. CSCE has played a significant role in ending the era of the cold war which has been maintained for almost 45 years since WWII, and has emerged as the pan-European security community for the security and peace of the entire Europe. Through the conclusion of the Maastricht Treaty of 1991, the member-states of EC have agreed upon the establishment of the United States of Europe by means of economic, political, and diplomatic-defense integration. They thought such a European political union would function as a common European defense system. However, each member-states of EC has different interests and different attitudes toward the formation of a common European security community as well as the roles and functions of WEU and NATO. The Unites States considers yet NATO will be an appropriate institution, if it expands its economic and political roles rather than the military role, even in the era of the post-cold war and international peace and cooperations. Generally speaking, it is a great advantage that CSCE has encompassed all the countries of western and eastern Europe, whereas its weakness is the lack of forcible means as a collective security system. WEU may be meaningful in that it is europeanized and will function as an European. security system, but it has limits in playing the role of the entire European security system. Although NATO has a strong organization and military power, but since it is the by-product of Cold War the expansion of influence of NATO following the collapse of the old USSR and the socialist camp will be misunderstood as that of the United States. In conclusion, therefore, it is a best alternative that by encouraging the advantageous points of CSCE, WEU, and NATO and complementing each weakness of others, these organizations .pursue the cooperation in the European security and peace

Cr 첨가 과공석강 선재에서 pearlite morphology가 신선가공earlite morphology on the cold drawing limit and the mechanical properties of drawn wires for Cr added hypereutectoid steel wire rod

Maste

공유재산의 적극적 관리방안에 관한 연구

학위논문(석사)--서울대학교 환경대학원 :환경계획학과 도시및지역계획전공,1996.Maste

작은 조절 RNA와 바이러스 RNA에 작용하는 단백질 기작에 관한 단일 분자 형광 연구

학위논문(박사)--서울대학교 대학원 :자연과학대학 물리·천문학부,2015. 8. 홍성철.Andrew Fire found that a specific gene was shut down with the destruction of messenger RNA (mRNA) when tiny snippets of double-stranded RNA (dsRNA) were injected into Caenorhabditis elegans in 1998. This phenomenon was RNA interference (RNAi), a biological process in the control of global gene expression, and it became one of most momentous biomedical discoveries of the last 30 years. The application of RNAi has revolutionized the studies of eukaryotic gene function in research laboratories, and the therapeutic potential for human disease treatment was also had captured the attention of the biological and medical communities. RNAi-based therapeutics were introduced into the clinical trials just six years after the discovery. Because components of the RNAi machinery are to be regulated extensively, it became a major challenge to understand their molecular mechanisms from the biogenesis to effective pathways. MicroRNAs (miRNAs) are ~22nt nucleotide endogenous RNAs central to RNAi with small interfering RNA (siRNA). RNA transcripts are process by Microprocessors in nucleus to be precursors of miRNAs. We observed the procedure that complexes of recombinant Drosha and DiGeorge syndrome chromosomal region 8 (DGCR8) fused to fluorescence proteins bind on hairpin structured primary miRNA at single-molecule level, and showed that a Microprocessor is composed of one Drosha molecule and two DGCR8 molecules. This stoichiometry issue was remained ambiguous due to the heterogeneous behaviors of Microprocessor components in the previous biochemical studies, but it could be clarified with real-time single-molecular observation. Argonaute proteins are highly conserved central effectors of RNAi among eukaryotes. The processed miRNAs incorporate with Argonaute proteins into the RNA-induced silencing complexes (RISCs), and the RISCs search and act on targets by miRNA sequence complementary. We observed target binding procedures of core-RISCs followed by target cleavage, guide RNA unloading, and stable binding pathways at single-molecule level with recombinant human Argonuate 2 and organic dye labeled RNA substrates. The whole procedure of core-RISC reaction was described with kinetic parameters at each stage including core-RISC recycling. Furthermore, we discovered the stable binding mode of core-RISC and RNA sequence dependency on core-RISC pathway providing a clue for improving siRNA design. Some viruses store their genetic information as long double stranded RNAs (dsRNAs), and they insert the RNA molecules into normal cells for infection. The normal cells should distinguish the exogenous RNAs from their endogenous RNAs and activate an immune system to survive, and one of the strategies is to measure the length of RNA molecules. Because normal cells do not have long dsRNA molecules, viral RNA invasion can be noticed if cells can discriminate the long dsRNA (> 1 kb) molecules. Previous cell studies showed that Melanoma Differentiation-Associated protein 5 (MDA5) would be essential for the process. By observing the formation and disassembling procedure of MDA5 filament on dsRNA in real-time at single-molecule level with an organic dye labeled recombinant MDA5 and dsRNAs, we explained the mechanism how small MDA5s can determine the length of dsRNA more than 100 times longer than them.Abstract Contents List of Figures and Tables Chapter 1 Introduction 1.1. Single-Molecule Fluorescence Spectroscopy 1.2. TIRF Microscopy for Single-Molecule FRET Measurement 1.3. RNA Biology References Chapter 2 Stoichiometry of DROSHA-DGCR8 Complex 2.1. Introduction 2.2. Materials and Methods 2.3. Results and Discussion 2.4. Conclusion and Outlook References Chapter 3 Diverse Reaction pathways of Human Argonaute 2 on target RNAs 3.1. Introduction 3.2. Materials and Methods 3.3. Results and Discussion 3.4. Conclusion and Outlook References Chapter 4 RNA Length Discrimination Mechanism by MDA5 Filaments 4.1. Introduction 4.2. Materials and Methods 4.3. Results and Discussion 4.4. Conclusion and Outlook References Abstract in Korean (국문초록) Publication List Acknowledgement (감사의 글)Docto