고분자 태양전지에 사용되는 DPP 기반 고분자의 불소 치환이 광전지 성능에 미치는 효과

학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2015. 2. 조원호.Low bandgap conjugated copolymers composed of thiophene-capped diketopyrrolopyrrole and benzene with/without fluorination were synthesized to investigate the effect of fluorine substitution on their photovoltaic properties. With increasing the number of substituted fluorine atom on benzene, both HOMO and LUMO energy levels of the copolymer are lowered and its crystallinity is increased. The fibril size of copolymer:PC71BM blend becomes smaller as the number of substituted fluorine increases. As a result, the copolymer with two fluorine substitution exhibits deeper HOMO energy level (-5.30 eV), leading to higher VOC (0.72 V), and also enhanced crystallinity (polymer chain packing), leading to higher JSC (12.4 mA cm-2) as compared to mono- and non-fluorinated ones. The copolymer with two fluorine atoms shows a promising power conversion efficiency of 5.63%.Abstract .. ⅰ List of Schemes ⅳ List of Figures ⅴ List of Tables ⅷ 1. Introduction 1 2 .Experimental Section 5 2.1. Materials 5 2.2. Synthesis of monomers 5 2.3. Synthesis of polymers 10 2.4. Characterization 13 2.5. Device fabrication and measurements 14 3. Results and Discussion 17 3.1. Synthesis and characterization 17 3.2. Optical properties 27 3.3. Electrochemical properties 28 3.4. Structural properties 29 3.5. Photovoltaic properties 35 3.6. Charge transport characteristics 36 3.7. Morphology investigation 46 4. Conclusions 48 Bibliography 49 Korean Abstract 53Maste

신경성장인자 공급 임플란트를 이용한 하치조신경 손상 치료에서 신경 재생 및 골유착에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 치의과학과, 2014. 2. 이종호.목적: 임플란트 시술이 대중화되면서 하치조신경 손상에 의한 감각 이상도 급격히 증가하고 있으며 그 중요성도 점점 부각되고 있다. 본 연구에서는 하치조신경 손상 수복 부위에 신경성장인자(NGF)를 공급할 수 있도록 특별히 제작된 치과 임플란트를 이용하여 NGF를 공급했을 때 신경 재생에 대한 효과를 평가하였으며, NGF 공급과 개조된 임플란트의 디자인이 임플란트의 골유착에 미치는 영향을 검증하고자 하였다. 재료 및 방법: 18주령 성견 (beagle dog, n=9)을 전신 마취시킨 후 양측 하치조신경을 노출시키고 하악 제3소구치를 발거한 후 NGF 공급 임플란트를 즉시 식립하였다. 임플란트에 근접한 부위의 하치조신경을 절단한 후 단단 문합하고 mini osmotic pump 카테터를 임플란트에 연결하였다. 우측 하치조신경에는 2mL의 NGF 용액 (150μg/mL)이 그리고 좌측 하치조신경에는 동량의 PBS 용액이 담긴 pump를 연결하였다. 신경재생 평가를 위해 술전 및 술후 3, 6주에 needle electrode를 이용해 진폭과 잠복시간을 측정하였고 신경절단 전후 및 술후 6주에 hook electrode를 이용해 신경전도속도와 최대전압을 측정하였다. 술후 6주에 손상부를 중심으로 신경표본을 채취한 후 시편 중앙부를 횡분절 (cross section)하여 epon 포매 절편 toluidine blue로 염색 후 전체 축삭 수, 축삭밀도를 측정하고 대표 부위를 TEM표본 제작하여 축삭 수초의 두께 및 G-ratio를 측정하였다. 임상적으로는 식립된 임플란트의 염증 등 부작용을 관찰하였으며, 술후 6주째 임플란트 안정도 (ISQ)를 측정하였다. 그리고 6주 후 희생 시 임플란트를 주변 조직과 같이 채취하여 탈회, 비탈회 표본을 제작하고 이를 통해 bone-implant contact (BIC) 비율과 bone area (BA) 비율을 측정하였다. 결과: 전기신경생리측정에서 진폭과 잠복시간은 두 군 사이에 유의한 차이가 없었다. 신경전도속도에서는 6주째 NGF군의 중앙값(2.675 m/s)이 PBS군(1.892 m/s)보다 유의하게 높았으며 (p < 0.01), 최대전압도 같은 결과를 보였다 (NGF vs. PBS : 1.940 μV vs. 1.300 μV, p < 0.01). 마찬가지로 NGF군의 전체 축삭 수 및 축삭밀도 (4576.107 ± 270.413, 10707.458 ± 638.835/mm2)가 모두 PBS군 (3606.972 ± 242.876, 7899.781 ± 1063.625/mm2)에 비해 유의하게 높았지만 (p < 0.001), G-ratio는 두 군간 차이가 없었다. BIC 는 NGF군이 46.609±6.521 %, PBS군이 42.884±6.489 % 였으며, 두 군 간에 유의한 차이는 없었다. BA (NGF vs. PBS : 36.993±7.0434% vs. 33.327±6.551 %)와 6주 후 ISQ (NGF vs. PBS : 42.375±3.017 vs. 38.714±2.533)에서도 두 군간 유의한 차이가 관찰되지 않았다. NGF 공급 임플란트의 전체 생존률은 83.33% 이었으며 NGF 군은 88.89%, PBS군은 77.78%였다. 결론: 본 연구에서 NGF 공급 임플란트를 이용한 NGF 공급은 하치조신경의 재생을 도모하였으며 이러한 처치가 골유착을 저해하지 않았음을 알 수 있었다. 이러한 치료 방식은 신경재생과 골유착을 동시에 도모할 수 있기 때문에 임플란트 식립과 관련된 하치조신경 손상치료의 새로운 가능성을 제시할 수 있다고 사료되었다.Purpose: Among the various complications of dental implant procedure, sensory disturbance caused by the damage of inferior alveolar nerve (IAN) is one of the most difficult and challenging issues with continually increasing incidence. The purpose of this study was to evaluate the functional regeneration of IAN by supplying nerve growth factor (NGF) using specially designed dental implant and its effect on the osseointegration of NGF-supplying implant. Materials and Methods: Under general anesthesia with intravenous injection of the mixture of tiletamine and zolazepam, bilateral IAN of beagle dogs (n=9, 18 week-old, 10 ~ 12kg) was exposed, transected and directly repaired. NGF-supplying implants were installed just above the nerve damage site after the third premolar extraction and connected with osmotic pump by microcatheter. For experimental group (right IAN), total 300μg of NGF mixed with 2mL PBS solution was loaded in the pump and same amount of PBS for control group (left IAN). The amplitude and latency were measured with needle-type electrodes before surgery and at postoperative 3, 6 week. The conduction velocity (CV) and peak voltage (PV) were measured with custom-made hook type electrodes before transection, after nerve repair and at postoperative 6 week. At 6 week, nerve specimens were harvested and embedded to calculate axon count and density. After that, TEM analysis was done to measure the myelin thickness and G-ratio. Dental implants were observed clinically with checking the implant stability quotient (ISQ). After 6 weeks, each dental implant was prepared for the decalcified and non-decalcified sections for the measurement of bone-implant contact ratio (BIC) and the new bone area inside the thread area (BA). Results: In the amplitude and latency, there were no significant differences between two groups. The median CV of NGF group (2.675 m/s) was significantly higher than that of PBS group (1.892 m/s) at 6 week (p < 0.01) and same tendency was also observed in PV (1.940 μV in NGF group and 1.300 μV in PBS group). The axon count of NGF group (4576.107±270.413) was higher than that of PBS group (3606.972±242.876) with significance (p < 0.001) and same as axon density (NGF group : 10707.458±638.835/mm2, PBS group : 7899.781±1063.625/mm2,p < 0.001). In myelin thickness, mean of NGF group (1.670±0.555 μm) was higher than that of PBS groups (1.173±0.388 μm) with significance (p < 0.01), but no significant difference was found in G-ratio between two groups (NGF vs. PBS, 0.594±0.110 vs. 0.635±0.092). The BIC of NGF group (46.609±6.521 %) was higher than that of PBS group (42.884±6.489 %), but no significant difference was found. The same tendency was found in the BA (36.993±7.0434 % in NGF group and 33.327±6.551 % in PBS group) and ISQ (42.375±3.017 in NGF group and 38.714±2.533 in PBS group). Overall survival rate of NGF-implant was 88.89% in NGF group (88.89%), and 77.78% in PBS group. Conclusions: NGF group showed higher conduction velocity and peak voltage across the nerve repair with significance. Same tendencies were also observed in amplitude and latency of CNAP, but there were no significant differences between two groups. In histomorphometric analysis, NGF group exhibited significantly higher axon count, axon density and myelin thickness than those of PBS group, but there were no significant differecence in G-ratio, BIC and BA. Except three exfoliated implants, no significant difference was found in ISQ between NGF group and PBS group at 6 week. These results showed that NGF supplying via specially designed dental implant could promote the functional regeneration of IAN transection-repair injury. Furthermore, supplied NGF and the design of implant did not interrupt the osseointetegration of implant. This approach could be a novel technique in the treatment of IAN injury, in which nerve regeneration and prosthetic rehabilitation could be achieved simultaneously.I. Introduction --------------------------------------- 1 II. Materials and Methods ----------------------------- 5 1. Experimental design -------------------------------- 5 2. Evaluation ----------------------------------------- 7 3. Statistics ---------------------------------------- 13 III. Results ----------------------------------------- 14 1. Gross clinical observation ------------------------ 14 2. Evaluation of nerve regeneration ------------------ 14 3. Evaluation of osseointegration -------------------- 17 IV. Discussion --------------------------------------- 19 V. Conclusions --------------------------------------- 24 References ------------------------------------------- 25 Figures and legends ---------------------------------- 35 Abstract in Korean ----------------------------------- 46Docto

Extraction of Host Internal Information for External Hardware Security Monitors

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2016. 2. 백윤흥.Defending electrical devices against a variety of attacks is a daunting task. A lot of researchers have endeavored to address this issue by proposing security solutions that can attain high level of security while minimizing performance overhead introduced to the system. Among them, hardware-based security solutions have been noted for high performance compared to their software-based counterparts. However, we have witnessed that these mechanisms have rarely been accepted to the market. This phenomenon may be attributed to the fact that most solutions incur non-negligible modifications to the host architecture internals and thus would substantially increase the design time and manufacturing cost. In order to answer this problem, a hardware-based external monitoring has recently been proposed. The crux of this solution is that, being located outside the host core and connected to the host via a standard bus interface, the external monitor can efficiently conduct time-consuming monitoring tasks on behalf of the host while requiring no alteration to the host internals. However, these approaches either suffer from the incapability of handling various security problems or experience unsubtle performance overhead because, being externally placed and having no dedicated communication channels, the hardware monitor has a limited access to the information produced by the host core, and consequently, the system may be forced to use memory regions or other shared hardware resources to explicitly transfer the information from the host to the monitor hardware. In this thesis, we propose a security solution that can carry out more complicated security tasks with low performance overhead while keeping the host internal architecture intact. This can be archived by using an existing standard debug interface, readily available in numerous modern processors, to connect our security monitor to the host processor. In order to show the validity of our approach and explore the implication of using the debug interface for security monitoring, we present three security monitoring systems each of which addresses one of three well-known security issues: defending against kernel rootkits, tracking information-flow, and defense of code-reuse attacks. The experiment results show that, when implemented on a FPGA prototyping board, our monitoring solutions successfully detect the attack samples (i.e., data leakage attacks and CRAs). More importantly, our systems can attain significantly low performance overhead compared to previously proposed security monitoring solutions. The experiments also reveal that the area overhead of the hardware is acceptably small when compared to the normal sizes of today's mobile processors.Chapter 1. Introduction 1 Chapter 2. Background and RelatedWork 8 2.1 Background 8 2.1.1 Core Debug Interface 8 2.2 Related Work 9 2.2.1 Software-based Monitoring solutions 10 2.2.2 Hardware-based Monitoring with Invasive Modification 10 2.2.3 Hardware-based Monitoring with Minimal Modification 11 2.2.4 Hardware-based Kernel Integrity Monitors 12 2.2.5 Utilizing debug interface 13 Chapter 3. Monitoring the Integrity of OS Kernels with Data-Flow Information 15 3.1 Introduction 15 3.2 Motivational Example 19 3.3 Assumptions and Threat Models 20 3.4 The Baseline System 21 3.4.1 The Overall System Design 21 3.4.2 Periodic Cache Flush for Cache Resident Attacks 23 3.5 Extrax design 25 3.5.1 Address Translation Unit 26 3.5.2 Early Stage Filter 28 3.6 Experimental Results 30 3.6.1 Prototype System 30 3.6.2 Security Evaluation 32 3.6.3 Performance Analysis 34 3.6.4 Power Consumption 36 3.7 Limitation and Future Work 36 3.8 Conclusion 39 Chapter 4. Monitoring Dynamic Information Flow using Control-Flow/Data-Flow Information 41 4.1 Introduction 41 4.2 DIFT Process with an External Hardware Engine 44 4.3 Building a DIFT Engine for CDI 48 4.3.1 Components of the DIFT Engine 48 4.3.2 Tag Propagation Unit 51 4.4 Experiment 53 4.4.1 Security Evaluation 56 4.4.2 Performance Evaluation 56 4.5 Conclusion 59 Chapter 5. Monitoring ROP/JOP Attacks using Control-Flow Information 60 5.1 Introduction 60 5.2 Background and Assumptions 65 5.2.1 Background 65 5.2.2 Assumptions and Threat Model 70 5.3 Overall System Architecture 71 5.3.1 SoC Prototype Overview 71 5.3.2 CRA Detection Process 72 5.4 IMPLEMENTATION DETAILS 75 5.4.1 Binary Instrumentation 75 5.4.2 Hardware Architectures 77 5.5 EXPERIMENTAL RESULTS 82 5.6 Conclusion 86 Chapter 6. Conclusion 88 Bibliography 90 초 록 99Docto

웨어러블 전자소자를 위한 금속성과 반도체성 탄소나노튜브 섬유 제조

학위논문(박사)--서울대학교 대학원 :공과대학 재료공학부,2019. 8. 유웅열.최근 웨어러블 전자소자는 인간 활동 및 개인 건강 관리와 같은 다양한 분야의 필요로 인해 유연하고 착용 가능한 기능성 전자소자의 개발에 많은 관심이 모아지고 있다. 이러한 웨어러블 전자소자에 사용되는 재료는 유연하고, 신축성이 있어야하며, 경량이며, 기계적으로 견고하고, 인간 친화적이어야 한다. 재료 중 가장 이상적인 재료는 직물에 사용할 수 있는 기능성을 가진 전자 섬유로써 구조적으로 변형 가능하거나 본질적으로 유연하고 신축성 있는 재료이다. 그러나 개발된 전도성 섬유 중 아직 웨어러블 전자소자에 사용하기에 적합한 전기적 및 기계적 특성을 갖는 섬유는 개발되지 않았다. 또한, 단일 유형을 섬유 형태의 전자소자는 개발되어 그 성능을 입증했지만 통합 다기능 웨어러블 플랫폼에 응용 할 수 있는 형태는 갖추지 못하고 있다. 본 논문에서는 탄소나노소재 기반 전도성 섬유의 전기 전도성 및 기계적 성질을 향상시키는 방법과 해당 섬유를 사용하여 웨어러블 전자소자에 응용 가능한 하이브리드 섬유 트랜지스터와 섬유형 포도당 센서를 제조하는 방법을 제안한다. 먼저, 섬유의 고유 기능을 부여하고 전기 전도도를 높이기 위해 분산, 정제 및 분리를 포함하는 탄소나노튜브 자체의 전처리에 중점을 둔다. 탄소나노튜브를 수용액 중에 잘 분산시킬 수 있는 분산제를 합성하여 사용하면 다량의 탄소나노튜브를 분산시킬 수 있다. 또한, 탄소나노튜브는 열처리 및 산처리와 같은 정제 공정을 거치면 고순도의 탄소나노튜브를 얻을 수 있다. 탄소나노리본의 첨가는 탄소나노튜브 섬유 내에서 탄소나노튜브 사이의 접착제로 작용하여 탄소나노튜브 간의 미끄러짐을 방지하여 섬유의 기계적 강도를 증가시킨다. 전처리 된 탄소나노튜브는 전기 방사 및 습식 방사를 통해 섬유로 제조된 후 그 성능을 평가한다. 다음으로, 하이브리드 섬유 트랜지스터와 섬유형 포도당 센서를 개발하기 위해 섬유의 응용에 중점을 둔다. 섬유 트랜지스터는 전도성 섬유, 고분자 절연 층, 유기 반도체 및 이온 젤을 포함하는 하이브리드 형태로 제조한다. 플라즈마 화학기상증착은 얇은 절연 층으로 게이트 섬유 전극을 덮기 위해 사용한 공정이다. 그리고 유기 반도체를 함유하고 있는 이온 겔을 잘라 붙여 섬유 사이에 결합하여 단위 트랜지스터를 형성한다. 또한, 단일벽 탄소나노튜브의 독특한 성질인 키랄성에 따른 특성을 이용하여 키랄성에 따라 분리한 후 섬유로 제조하여 섬유 자체에 기능을 부여한다. 합성한 분산제를 사용하여 얻은 높은 함량의 탄소나노튜브가 분산된 용액을 전기 방사하면 탄소나노튜브를 많이 포함하고 잘 정렬된 높은 전기 전도성의 복합나노섬유를 제조한다. 또한, 정제한 탄소나노튜브를 사용하여 습식 방사하면 높은 전기 전도도를 보이는 섬유를 제조하며, 탄소나노리본을 혼합하여 높은 인장 강도를 보이는 섬유를 제조한다. 제조한 고 전도성 섬유는 섬유 트랜지스터의 전극으로 사용한다. 또한, 분리를 통해 제조한 반도체성 섬유는 다양한 통합 형태의 웨어러블 전자소자에서 직조를 통해 포도당 센서로 활용할 것으로 기대한다.Wearable electronic devices are required in various fields such as monitoring human activity and personal health care. Thus, in recent years, much attention has been paid to the development of flexible and wearable functional electronic devices. The materials used in these wearable electronic devices must be flexible, stretchable, light-weight, mechanically robust and human-friendly. The most ideal material among the materials is either structurally deformable or intrinsically flexible and stretchable material, e.g. textiles containing all electronic functions intrinsically embodied in the electronic fibers themselves. However, none of the developed conductive fibers have electrical and mechanical properties suitable for use in wearable electronic devices. In addition, a single type of fiber-based electronic device has been developed and demonstrated its performance, but there are still few reports on an integrated multifunctional wearable platform. This dissertation suggests improvement of the electrical conductivity and mechanical properties of conductive carbon-based fibers and separation for semiconducting carbon-based fibers, applying on the hybrid fiber transistor and the fiber-type glucose sensor that can be integrated into textile-type of wearable electronic devices. Firstly, to increase the electrical conductivity and to give the intrinsic functionality of the fiber, the pretreatments of the carbon nanotubes themselves are followed: Dispersion, purification, and separation. A large amount of carbon nanotubes were dispersed by a dispersant synthesized that enables carbon nanotubes to be dispersed well in an aqueous solution. In addition, high-purity carbon nanotubes were obtained through purification process: heat and acid treatments. The addition of the carbon nanoribbon acts as an adhesive between the carbon nanotubes due to pi-pi interaction, thereby preventing slip between the carbon nanotubes, leading to increase mechanical strength of carbon fibers. The pretreated carbon nanotubes were manufactured by electro-spinning and wet-spinning and then evaluated for their performance. Next, the applications of above fibers to develop fiber transistors and glucose sensors are followed. Fiber transistors are made in hybrid form, including conductive fibers, polymer insulating layers, organic semiconductors, and ion-gels. Plasma enhanced chemical vapor deposition was used to cover the surface of the gate fiber electrode with a thin insulating layer. Then, a cut-and-stick method was used to incorporate an ion-gels contained organic semiconductor into the fibers to form a unit transistor. Besides, the single-walled carbon nanotubes were separated depending on their chirality to give functions intrinsically to the fibers themselves. The fibers that are electro-spun with a dope solution in which high content of carbon nanotubes are dispersed through the synthesized dispersant became high conductive composite nanofibers, which contains a lot of aligned carbon nanotubes. Also, The carbon fibers wet-spun by the purified carbon nanotubes showed high electrical conductivity and by the mixture dope of carbon nanotubes and nanoribbons achieved high tensile strength. For the applications, highly conductive fibers were used as electrodes in fiber transistors. Also, the functionalized semiconducting fibers have been shown to act as glucose sensors, expecting to work as a glucose sensor through weaving in various integrated forms of wearable electronics.1 INTRODUCTION 1 1.1 Overview of Fiber-Based Wearable Electronics . . . . . . . . . . . . 1 1.1.1 Fiber Components for Wearable Electronics . . . . . . . . . . 2 1.1.2 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Overview of Carbon Materials for Wearable Electronics . . . . . . . . 6 1.2.1 Conductive Electrodes . . . . . . . . . . . . . . . . . . . . . 6 1.2.2 Electrochemical Sensors . . . . . . . . . . . . . . . . . . . . 7 1.2.3 Integrated Wearable Electronics . . . . . . . . . . . . . . . . 8 2 ELECTRO-SPUN METALLIC CNT NANOFIBERS 10 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2.1 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2.2 Preparation of Dope Solutions . . . . . . . . . . . . . . . . . 12 2.2.3 Electrospinning Conditions . . . . . . . . . . . . . . . . . . . 13 2.3 Characterizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3.1 Morphology Analysis . . . . . . . . . . . . . . . . . . . . . 13 2.3.2 Electrical Conductivity Measurements . . . . . . . . . . . . . 13 2.4 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4.1 Dispersion of CNT . . . . . . . . . . . . . . . . . . . . . . . 15 2.4.2 Morphologies of CNT Nanofibers . . . . . . . . . . . . . . . 19 2.4.3 Electrical Conductivity of CNT Nanofibers . . . . . . . . . . 19 2.4.4 CNT Concentrations of CNT Nanofibers . . . . . . . . . . . 24 2.4.5 CNT Alignment of CNT Nanofibers . . . . . . . . . . . . . . 25 2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3 WET-SPUN METALLIC CNT MICROFIBERS 28 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.2.1 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.2.2 Preparation of Dope Solutions . . . . . . . . . . . . . . . . . 31 3.2.3 Wetspinning Conditions . . . . . . . . . . . . . . . . . . . . 33 3.2.4 Plasma Deposition System . . . . . . . . . . . . . . . . . . . 33 3.2.5 Preparation of Semiconducting Channel . . . . . . . . . . . . 33 3.3 Characterizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.3.1 Purity Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.3.2 Electrical Conductivity Measurement . . . . . . . . . . . . . 38 3.3.3 Tensile Strength Measurement . . . . . . . . . . . . . . . . . 38 3.3.4 Insulating Layer . . . . . . . . . . . . . . . . . . . . . . . . 38 3.3.5 Transistor Characteristics . . . . . . . . . . . . . . . . . . . . 39 3.4 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 39 3.4.1 Characterizations of CNT . . . . . . . . . . . . . . . . . . . 39 3.4.2 Morphologies of CNT Microfibers . . . . . . . . . . . . . . . 48 3.4.3 Electrical and Mechanical Properties of CNT Microfibers . . . 48 3.4.4 Characterizations of Insulating Layer . . . . . . . . . . . . . 51 3.4.5 Performance of Fiber Transistors . . . . . . . . . . . . . . . . 56 4 WET-SPUN SEMICONDUCTING CNT MICROFIBERS 61 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 4.1.1 Semiconducting CNT . . . . . . . . . . . . . . . . . . . . . 61 4.1.2 Glucose Sensor . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.2 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 4.2.1 Separation of Semiconducting CNT . . . . . . . . . . . . . . 64 4.2.2 Enzyme Immobilization . . . . . . . . . . . . . . . . . . . . 65 4.3 Characterizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 4.3.1 Optical Characterizations . . . . . . . . . . . . . . . . . . . . 65 4.3.2 Electrochemical Characterizations . . . . . . . . . . . . . . . 65 4.3.3 Atomic Structure Characterizations . . . . . . . . . . . . . . 67 4.3.4 Amperometric Electrochemical Analysis . . . . . . . . . . . 67 4.3.5 Gate Effect Measurement . . . . . . . . . . . . . . . . . . . . 70 4.4 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 70 4.4.1 Graphitic Structures of CNT . . . . . . . . . . . . . . . . . . 70 4.4.2 Energy Levels of CNT . . . . . . . . . . . . . . . . . . . . . 74 4.4.3 Chirality of CNT . . . . . . . . . . . . . . . . . . . . . . . . 77 4.4.4 Transistor Characteristics . . . . . . . . . . . . . . . . . . . . 77 4.4.5 Fiber-Type Glucose Sensor . . . . . . . . . . . . . . . . . . . 80 5 CONCLUSION 85 Abstract (In Korean) 116Docto

Use of field observations to characterize a fractured porous aquifer system in Won-Ju, Korea

Thesis (master`s)--서울대학교 대학원 :지질과학과 지질학전공,1998.Maste

Significance of interrelationship between cardiac mcrovasculature, myuocytes, and collagen framework on the mechanisms of hypertensi

의학과/박사[한글] 당뇨병은 매우 흔한 전신질환으로서 특히 심혈관계에는 관상동맥 경화증이 없이도 심부전증을 흔히 유발시키며 고혈압의 발생빈도도 증가하고 있다. 그동안 많은 연구자들이 백서에서 당뇨병과 고혈압을 동시에 유발시켜(고혈압-당뇨성 심근증 백서, HD-CM) 심장의 여러가지 기능적, 구조적 이상을 관찰, 보고하였다. 그러나 심근을 지탱해주는 결체조직 구조의 역할에 대해서는 전혀 연구가 이루어지지 않은 실정이다. 따라서 본 실험에서는 고혈압 유발 백서, 당뇨병 유발 백서, 고혈압-당뇨성 심근증 백서에서 심장의 조직학적 변화중 결체조직 구조의 변화, 특히 심근내 교원질의 변동을 알아내고, 심근세포와 결체조직간의 상호관계 손상이 심기능에 미치는 영향과 심근 미세혈관 구조의 변화, 고혈압 및 협심증의 개선제인 diltiazem이 심근중에 미치는 영향을 알아보고자 하였다. Silver clip을 좌신동맥에 끼워 신성 고혈압을 유발하고 streptozotocin을 정맥내 주사하여 당뇨병을 유발하였으며, 이 두가지를 같이 처치하여 고혈압과 당뇨병을 동시에 유발시키고, 이들에 diltiazem을 투여하여 정상 대조군과 함께 심근의 조직병리학적 특성을 관찰하고 교원질을 측정하였으며, microfil 관류실험을 통해 미세혈관의 변화를 관찰하였다. 또, modified del Rio Hortega's silver carbonate impregnation 방법에 의해 결체조 직 구조를 관찰하였다. 체중에 대한 심장의 상대적인 무게는 전 실험군이 정상 대조군에 비해 증가되어 심비대가 일어난 것을 알 수 있었고 심근의 간질섬유화, 혈관주위 섬유화, 혈관경화, 미세혈관의 변화등은 당뇨병 단독유발군에서는 정상 대조군과 거의 차이가 없었으나 고혈압 단독 유발군과 고혈압-당뇨병 동시유발군에서는 현저하게 증가된 소견을 보였다. 대치섬유화도 고혈압-당뇨병 동시유발군에서 많이 관찰되었다. 간질섬유화의 정도는 혈관주위 섬유화의 정도와 비례하였으나 수축기 혈압, 몸무게에 대한 심장의 무게 비율, 고혈당의 정도와는 상관관계가 없었다. 심근내 비교원질성 단백질에 대한 교원질 양의 비율은 전 실험군이 정상 대조군에 비해 약간 높은 경향을 보였다. 고혈압 단독유발군에서는 세포외 결체조직 성분의 증식이 있었으나 배열및 연결 상태는 정상이었고, 당뇨병 단독유발군에서는 결체섬유의 증식은 없었으나 근세포 섬유의 연결이 끊어진 것이 관찰되었고, 고혈압-당뇨병 동시유발군에서는 결체섬유의 증식과 연결이상이 동시에 나타났다. Diltiazem을 투여한 백서에서는 비투여군에 비해 혈압이 낮았고 간질섬유화와 대치섬유화, 혈관주위 섬유화, 혈관경화등의 조직학적 이상이 적었으며 미세혈관의 변화도 역시 더 적은 것으로 관찰되었다. 이상의 결과로 보아 당뇨병과 고혈압이 같이 발생되는 경우 주로 당뇨병에 의한 것으로 생각되는 기능 저하와, 주로 고혈압의 영향인 심한 심근의 구조적 손상이 상승작용을 하여 흔히 심근증으로 발전되며, 이의 발생기전은 심장내 미세혈관의 경련으로 인한 재관류 손상에 의해 심근세포의 괴사가 발생하고 여기에 미세혈관 누출로 인한 간질부종과 섬유화에 의한 것으로 여겨진다. 또, diltiazem은 미세혈관 변화를 포함한 심장의 구조적 변화를 경감시키는 효과가 있는 것으로 보아 앞으로 더욱 규명해 볼 가치가 있는 것으로 여겨진다. [영문] Semiquantitative histopathologic changes, myocardial collagen content and intramural microvascular changes using Microfil perfusion, and morphologic change of connective tissue framework by modified del Rio Hortega's silver carnonate impregnation method were studied in hypertensive, diabetic, hypertensive-diabetic, and control rats. Diltiazem, a calcium channel blocking agent, was administered orally into half of the hypertensive-diabetic group and the myocardial protective effect of this agent was also evaluated. The observed results are summarized as follows: 1 . Blood pressures were significantly elevated in hypertensive and hypertensive-diabetic rats, and were less elevated in diltiazem-treated group compared with untreated group. 2. All the experimental groups showed higher heart weight/body weight ratio than controls. Among the hypertensive-diabetic rats, the ratio was higher in diltiazem-treated group. 3. Both hypertensive-diabetic and hypertensive groups showed significant perivascular fibrosis. Vascular sclerosis was more frequently observed in hypertensives than in hypertensive-diabetics. Diltiazem-treated group had lesser degree of perivascular fibrosis and vascular sclerosis than untreated. 4. Interstitial fibrosis was increased significantly in hypertensive-diabetic animals, while diabetic rats showed only minimal fibrotic changes as in controls. Also, diltiazem-treated rats showed lesser degree of interstitial fibrosis than untreated. 5. The degree of interstitial fibrosis was well correlated with the decree of Perivascular fibrosis, but was not correlated with systolic blood pressure, cardiac weight/body weight ratio, or blood glucose level. 6. The ratio of myocardial collagen content to noncollagenous protein was elevated in the all experimental animals compared with the controls, and it was higher in the diltiazem-untreated group among the hypertensive-diabetic animals. 7. Microvascular changes observed in Microfil perfusion study were prominent in hypertensive and hypertensive-diabetic groups which showed vascular constriction, tortuosity and microaneurysm formation. But microvascular changes of diabetic group were similar to those of controls. Diltiazem-treated rats showed significantly less microvascular changes than untreated group. 8. There was an increase in the connective tissue matrix demonstrated with the silver impregnation technique in the hypertensive and hypertensive-diabetic groups. However, the hypertensive-diabetic group revealed multiple foci of silver negative zone with torn, distorted or disconnected connective tissue fibers, in addition to increased comnective tissue matrix. This investigation with extensive comparison of five groups of rats with hypertension and/or diabetes or no disease with or without diltiazem treatment, has revealed that there are relatively severe functional changes in myocardium caused by diabetes that are reversible and not associated with significant tissue damage. Hypertension causes more moderate functional changes but more extensive morphologic damage in the myocardium with interstitial and replacement fibrosis. Stable and reversible left ventricular dysfunction may ensue, but the heart does not progress to a cardiomyopathic stage. The combination of diabetes and hypertension, however, causes both severe functional changes and significant widespread myocardial injury. There is thus a dual and additive cardiac insult: extensive myocardial cell loss contributing to systolic dysfunction and multifocal fibrosis with Possible interstitial matrix increase leading to diastolic dysfunction, and metabolically affected myocytes with decreased mechanical and electrophysiological capability also leading to systolic and diastolic dysfunction. Of the two insults, the morphologic damage is irreversible; therefore prevention of this injury may ameliorate the progression to cardiomyopathy. There is evidence that the microvasculature in these animals is abnormal, with changes suggestive of spasm and vessel wall lesions. We believe that the pathogenesis of the myocardial damage is related to the induction of reperfusion induced myocyte necrosis due to spasm, and interstitial edema and fibrosis due to microvascular leakage. It is possible that pharmacologic inhibition of the microvascular changes in hypertension and diabetes may limit the progression of the disease to cardiomyopathy. The diltiazem treatment for hypertensive-diabetic cardiomyopathy should be tested further.restrictio

백서 좌골 신경 손상부위에 제대중간엽 줄기세포와 슈반세포 이입을 이용한 말초 신경 재생

Thesis(masters) --서울대학교 대학원 :치의학과,2008.2.Maste

새로운 형태의 결합력인 양이온 - 상호작용의 근원

Maste

Nonlinear optical properties and molecular vibrations of polyene derivatives

Docto

VLIW ASIP for H.264 Integer transform and Quantization

학위논문 (석사)-- 서울대학교 대학원 : 전기. 컴퓨터공학부, 2011.2. 백윤흥.Maste