A study on the preparation of microporous polymer papers or sponges and their pore structures

학위논문 (박사)-- 서울대학교 대학원 : 재료공학부, 2015. 8. 장지영.Microporous organic polymers are of great interest due to their large surface area, physicochemical stability, and easy modification of their chemical structures. They have potential applications in gas storage, separation, and sensing. However, most porous polymers are obtained as insoluble powders, complicating their use in practical applications. In this study, various microporous polymers were prepared in the form of papers, sponges, or thin films. First, a microporous polymer paper (MPP) was prepared via the Sonogashira coupling reaction of 1,4-diiodotetrafluorobenzene and 1,3,5-triethynylbenzene. MPP was thin, flexible, and foldable, similar to classic paper. It had an interconnected network structure of hollow tubes and polymer showed superhydrophobicity with a water contact angle of 162o. Cryogenic nitrogen adsorption experiments showed that MPP has a microporous structure with a BET surface area of 715 m2g-1. The CO2 and H2 uptake amounts of MPP at 1 bar were 35.5 cm3g-1 at 273 K and 1.26 wt% at 77 K, respectively. The selectivity of CO2 over N2 at room temperature was 17.6. The measured iodine uptake of MPP was found to be 65 wt%. Secondly, compressible monolithic microporous polymer sponges were prepared via the Sonogashira coupling reaction of 1,3,5-triethynyl benzene and 1,4-diiodobenzene (MPS1) or 4,4-diiodobiphenyl (MPS2) at room temperature. SEM and TEM images of these polymers showed bundled hollow tubular microstructures. The sponges completely recovered their initial shapes after 95 % compression. Cryogenic nitrogen adsorption experiments showed that the sponges had high BET surface areas of up to 1090 m2g-1. The CO2 and H2 uptake amounts of MPS1 at 1bar were 49.9 cm3g-1 at 273 K and 1.93 wt% at 77 K, respectively. MPS1 had a high water contact angle of 150o and could remove hydrophobic solvents on water. MPS1 showed good filtration performance for small molecules such as dye molecules or VOC gases. Lastly, a hyperbranched polymer was used as a building block for the synthesis of a microporous organic polymer. Hyperbranched polyphenylenes were prepared from (3,5-dibromophenyl)boronic acid, which contained numerous unreacted bromophenyl end groups. Utilizing metal-catalyzed coupling reactions between these functional groups, cross-linked porous polymers were obtained. Although the hyperbranched polyphenylenes did not show porosity, their cross-linked polymers had highly porous structures with BET surface areas of up to 2030 m2g-1. An insoluble porous thin film was fabricated by the spin casting of a solution containing a hyperbranched polyphenylene followed by a Sonogashira cross-coupling reaction.Abstract i Contents iv List of Schemes vi List of Tables vii List of Figures viii Chapter I. Introduction 1 I-1. Introduction to Microporous Materials 2 I-2. Preparation Methods of Microporous Organic Polymers 5 I-2-1. Condensation Reaction 8 I-2-2. Metal-Catalyzed Reaction 11 I-3. Applications of Microporous Organic Polymers 16 I-3-1. Hydrogen Storage 16 I-3-2. Carbon Dioxide Sorption 19 I-3-3. Volatile Organic Compounds Removal 21 I-3-4. Gas Separation 21 I-3-5. Heterogeneous Catalysis 22 I-3-6. Explosive Material Sensor 24 I-4. Shape Control of Microporous Polymers 25 I-5. References 28 Chapter II. Preparation of Microporous Polymer Paper 37 II-1. Introduction 38 II-2. Experimental 41 II-3. Results and Discussion 44 II-3-1. Synthesis and Characterization 44 II-3-2. Gas Adsroption Properties 57 II-3-3. Iodine Uptakes 62 II-4. Conclusions 67 II-5. References 68 Chapter III. Preparation of Microporous Polymers in the Form of Monolithic Sponges 73 III-1. Introduction 74 III-2. Experimental 75 III-3. Results and Discussion 78 III-3-1. Synthesis and Characterization of Microporous Polymer Sponge 78 III-3-2. Gas Adsorption Properties 90 III-3-3. Molecules Removal Performance 96 III-4. Conclusions 102 III-5. References 103 Chapter IV. Preparation of Microporous Polymers in the Form of Particles and a Thin Film from Hyperbranched Polyphenylenes 108 IV-1. Introduction 109 IV-2. Experimental 111 IV-3. Results and Discussion 116 IV-3-1. Synthesis and Characterization of Microporous Polymer 116 IV-3-2. Gas Adsorption Properties 124 IV-3-3. Dye Uptake Properties 128 IV-3-4. Film Fabrication 130 IV-4. Conclusions 132 IV-5. References 133 국문요약 138Docto

이미지 분할 인식을 이용한 스타일 전이 학습

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 산업공학과, 2018. 2. 이재욱.Recently, there are many studies in image style transfer. Image style transfer method transfers the style to the content image. However, it has a problem that it transfers the same style in different semantics. Thus, we proposed a new method named 'Segment style transfer'. Our method is composed of 4 phases: 'Image Segmentation', 'Segment Matching', 'Segment Style Transfer', and 'Segment Merging'. Our Segment style transfer method improves the existing image style transfer in that it does not make the transferred image heterogeneous and improve the image quality.Chapter 1 Introduction 1 1.1 Contributions 2 1.2 Related Work 3 Chapter 2 Image Style Transfer 7 2.1 Chapter Overview 7 2.2 Convolutional Neural Network 8 2.2.1 Convolutional layer 8 2.2.2 Pooling layer 9 2.2.3 Backpropagation 9 2.3 Content Reconstruction 11 2.4 Style Reconstruction 12 2.5 Image Style Transfer 13 Chapter 3 SegNet 15 3.1 Chapter Overview 15 3.2 Fully Convolutional Network 16 3.3 Encoder Network 17 3.4 Decoder Network 17 Chapter 4 Segment Style Transfer 19 4.1 Image Segmentation 19 4.2 Segment Matching 21 4.3 Segment Style Transfer 23 4.4 Segment Merging 25 4.5 Experimental results 26 Chapter 5 Conclusion 31 5.1 Summary of research 31 5.2 Implication of our work 32 Appendix A 33 Bibliography 35 국문초록 39Maste

Superconductor-insulator transition in dual-gated bilayer-graphene proximity Josephson junction

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Continuous and reversible tuning of the disorder-driven superconductor–insulator transition in bilayer graphene

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