Water Motion Active Transducer for Energy Harvesting

학위논문 (박사)-- 서울대학교 대학원 : 융합과학부, 2017. 2. 김연상.As effective methods to convert mechanical motion to electrical power, various transducers, such as electromagnetic inductive transducers, piezoelectric transducers, and variable capacitive transducers have been developed. The electromagnetic inductive transducers defined by Faradays law are predominantly used for electric energy harvesting from mechanical motion. Furthermore, the piezoelectric transducers are becoming an emerging technology for self-powered portable devices. Otherwise, in spite of the potential for energy transducing by variable capacitance, it remains in an infant state for energy harvesting, because it needs additional external bias-voltage sources for the accumulation of charge at the electrodes, which requires a passive transducer, or toxic liquid metals for effective induction. Also, their sources for energy harvesting are restricted only to artificial intermittent stimulation, like pushing or vibration. To overcome the limitations, I propose a water active capacitive transducer (WMAT) as an energy harvester to effectively generate electric power from the natural motion of water without any external bias voltage sources. One of the most significant limitations in applying capacitive transducers as energy harvesters is that they need an external bias-voltage source to accumulate charge at the electrodes. In my research, two types of WMAT devices are proposed according to various applications. First, I designed the WMAT with a simple structure consisting of PVP dielectric layer, hydrophobic layer on the rigid substrate. This simple structure has considerable advantages for the process and manufacturing cost. All fabrication processes for the WMAT were solely conducted by solution processes without any vacuum or high-cost processes. Second, I introduced a fabric-based WMAT using fabric materials with flexible and stretchable for wearable electronics. In this experiment, core materials for electrification and EDL to generate the electricity are PVP and PMMA energy conversion layers. I studied an effective fabrication method using newly adopted fabric-based materials and polymer materials to find easy and simple method differ from the conventional complex process. Furthermore, I carried out spray coating and transfer process with fabric material to overcome the limitation of spin coating and lithography process of high temperature and chemical treatment. The simple and low-cost process is the most attractive of all of the advantages of the WMAT in comparison to other energy harvesters with complex structures and cumbersome processes. With variation of the overlapping areas between the water and electrodes, this energy transducer could sufficiently convert the energy from the water's mechanical motion to electric energy. From a simple structure, we successfully generated electricity enough to turn on an LED using various kinds of natural water motion. The WMAT, which has wide applicability, has good potential to be a candidate for generating sustainable electric energy.Chapter 1. Introduction 1 1.1 Introduction 1 1.2 References 5 Chapter 2. Literature Review 7 2.1 Energy Harvesting Type 7 2.1.1 Piezoelectrics 11 2.1.2 Triboelectrics 19 2.1.3 Thermoelectrics 26 2.2 Energy Harvesting Technologies Using Liquid 32 2.3 References 42 Chapter 3. Water Motion Active Transducer 57 3.1 Overview & Motivation 57 3.2 Water Motion Active Transducer Structure & Material 62 3.3 Flowing Type WMAT 66 3.4 Pushing & Dipping Type WMAT 79 3.5 Fabrication of WMAT by Solution Process 92 3.6 Performance Characterization of WMAT 95 3.7 Conclusions 96 3.8 References 98 Chapter 4. Fabric-based Water Motion Active Transducer 103 4.1 Overview 103 4.2 Structure & Material of Fabric WMAT 109 4.3 Spray-assisted Process for Fabric WMAT 111 4.4 Electrical Property & Stability 117 4.5 Conclusions 129 4.6 References 131 Chapter 5. Conclusion 136 초록(국문) 139Docto

행정소송법상 처분의 개념

학위논문(석사)--서울대학교 대학원 :법학과 행정법전공,1998.Maste

전이금속 촉매를 이용한 생물학적으로 유용한 구조의 탄소-수소결합 활성화에 관한 연구

학위논문(박사) - 한국과학기술원 : 화학과, 2016.2 ,[iii, 114 p. :]Part 1. $Rh^I$ -Catalyzed Site-Selective Decarbonylative Alkenylation and Arylation of Quinolones An efficient catalytic system for the C2 selective C？H functionalization of N-pyrimidyl-4-quinolones was developed using a decarbonylative coupling mechanism. The installation of an N-pyrimidyl group on the quinolone nitrogen atom redirected the coordination between the catalyst and the carbonyl group to promote direct C？H functionalization at the C2-position of 4-quinolones intstead of C5. In addition, the present pro-tocol was successfully applied to the C3 selective installation of a variety of aryl and vinyl groups on an iso-quinolone scaffold. Keywords : decarbonylative coupling, C-H functionalization, quinolone, isoquinolone Part 2. Pd-Catalyzed Asymmetric Decarboxylative Allylation of Morpholinones: Strategy for Chiral Morpholine and Unnatural Amino Acid Synthesis We tried to develop an enantioselective reaction to yield quaternary chiral center using palladium(0) catalyzed decarboxylative allylation. Using this asymmetric method, introducing a quaternary chiral center onto C3 position of morpholine derivatives. During this research, we were able to introduce new PHOX type ligand which modifies enantioselectivity. Keywords : decarboxylative allylation, chiral quaternary center, morpholine, morpholinone Part 3. Pd-Catalyzed One-Pot Synthesis of 6-Aryl-2-α-styrylpyridines with Triazolopyridines We developed a new strategy for Pd-catalyzed synthesis of 6-aryl-2-α-styrylpyridines from tria-zolopyridines, wherein switchable chemical transformations (C3 vs C7) is observed by differentiating sub-strates using different bases. Two separate arylation catalyses were successfully performed in a tandem se-quence, providing convenient access to 6-aryl-2-α-styrylpyridines with various triazolopyridines.한국과학기술원 :화학과