입자결합모델을 이용한 RC 라멘 구조물의 발파해체 붕괴거동 모사에 관한 연구

학위논문(석사) --서울대학교 대학원 :에너지시스템공학부,2008.2.Maste

마이크로스케일 두께의 소프트 센서 제작을 위한 금속-폴리머 박막의 열증착 공정

학위논문(박사) -- 서울대학교대학원 : 공과대학 기계공학부, 2024. 2. Yong-Lae Park.Soft sensors, taking advantage of their inherent mechanical compliance stemming from the material itself, have demonstrated excellent adaptability to the external stim- uli. Leveraging their ability to detect various types of mechanical stimuli under large deformations, soft sensors play a pivotal role in wearables, human sensing, and human- robot interaction. When integrating soft sensors into the host system for sensing ap- plications, one key consideration is that the integration of the sensor itself should not affect the original system. As a result, there is a pressing demand for soft sensors with compact form factor, with minimized mechanical interference in the host system upon integration. Despite the increasing demand for soft sensors with a compact form factor for its seamless integration onto the original system, downsizing the thickness of soft sensors into the micrometer scale while maintaining sensing performance has been a challenge. In this dissertation, we introduce metallic thin films deposited onto a soft elastomer surface to soft sensing mechanisms, enabling soft sensors with micrometer-scale thick- ness. soft sensing mechanisms including soft optical sensing, resistive sensing, and capcitive sensing mechanisms are realized by metallic thin films deposited onto soft elastomer surface through thermal evaporation process. Novel deposition methods to fabricate mechanically robust metallic thin films onto a soft silicone surface are pro- posed, including rigid metals like gold or silver, and a metal alloy of gallium and indium that remains in a liquid phase at room temperature. Deposited metal-polymer thin films are then utilized to realize ultra-slim soft sensing mechanisms that can be readily integrated into a soft robotic system or human sensing system with minimal mechanical interference to the host system. First, a novel fabrication method to deposit rigid metallic thin films onto silicone rubber surface, namely layer transfer deposition method (LTD) is proposed. The bond- ing between the metal particles and silicone surface is enhanced with cross-linking of polymer upon curing of silicone rubber. Fabricated metallic film is adopted as a re- flective layer in soft optical waveguides that can detect mechanical deformations such as bending, compression, and strain. The soft optical waveguide is seamlessly inte- grated to a soft pneumatic actuator with minimal mechanical interference, imparting proprioception and enabling closed-loop feedback control of the actuator. Second, a novel deposition method for fabricating liquid-metal thin films onto polydimethylsiloxane (PDMS) surface, namely layer-by-layer (LBL) deposition method is proposed. PDMS surface is pre-deposited with indium, followed by a sequential de- position and passivation of gallium. The gallium(III) oxide skin that develops on the gallium surface is utilized as an isolating boundary between deposited gallium layers, and multilayered liquid-metal microstructures are developed on the PDMS surface. The electrical conductivity of the fabricated film is enhanced when the film is subjected to mechanical strain, as the strain induces rupture of oxide skin that causes coalescence of liquid metals. Fabricated film showed high electrical conductivity (2.37× 106 S/m) with high robustness under repeated mechanical deformation and low gauge factor (gauge factor GF = 1). Various applications including skin-mountable circuits, energy harvesters, and soft artificial skin-like sensors are prototyped, showcasing its versatil- ity and potential as a stretchable thin-film conductor. Finally, a multimodal soft sensor with an ultra-slim form factor (thickness< 100 µm) is developed. The proposed sensor is capable of detecting in-plane strains in two or- thogonal axes, and out-of-plane contact pressure. The proposed sensor comprises two resistive sensing elements and a capacitive sensing element, all composed of highly stretchable liquid-metal thin-films fabricated by LBL deposition method. It can de- couple the three different deformation modes with three distinct output signals from each sensing components.To demonstrate its capabilities within the realm of human- robot interaction, the proposed sensor was placed on a wrist as a sensing skin for teleoperating a robotic arm. keywords: Soft Sensors, Soft Robotics, Thin Films, Thermal Evaporation, Liquid Metals, Multimodal Sensors student number: 2018-22238Abstract i Contents iv List of Tables vii List of Figures viii 1 INTRODUCTION 1 1.1 Motivation 1 1.2 Related Works 3 1.3 Contribution . 6 1.4 Thesis Outline 8 2 Optically Sensorized Elastomer Air Chamber for Proprioceptive Sensing of Soft Pneumatic Actuators 11 2.1 Background . 11 2.2 Soft Optical Waveguide . 13 2.2.1 Design 13 2.2.2 Layer Transfer Deposition . 17 2.2.3 Metal Layer Robustness Analysis 19 2.3 Sensor-Integrated Soft Actuator 21 2.3.1 Sensorized Pneumatic Chamber . 21 iv 2.3.2 Design and Fabrication 23 2.4 Experiments and Results 25 2.4.1 Experimental Setup 25 2.4.2 Characterization 25 2.4.3 System Robustness 30 2.4.4 Control Strategy and Results 33 2.5 Application . 34 2.6 Summary and Discussion 34 3 Liquid-metal micro-networks with strain-induced conductivity for soft elec- tronics and robotic skin 37 3.1 Background . 37 3.2 Formation of multilayered LM microstructures using LBL deposition 40 3.3 Transition of multilayered LM structures to LMMN films . 54 3.4 Strain-induced conductivity enhancement of LMMN films 57 3.5 Applications for skin-like devices . 62 3.6 Methods 69 3.6.1 Materials . 69 3.6.2 Preparation of Substrates 69 3.6.3 Fabrication of LMMN Films 70 3.6.4 Materials Characterization . 70 3.6.5 Electromechanical Characterization 70 3.6.6 Teleoperation of a robotic hand . 72 3.6.7 Demonstration as an energy harvester . 72 3.7 Summary and Discussion 72 4 Ultra-Thin Multi-Modal Soft Sensor Using Liquid-Metal Thin-Film De- position for Enhanced Human-Robot Interaction 76 4.1 Motivation 76 v 4.2 Design . 80 4.2.1 Resistive Sensing Layer 80 4.2.2 Capacitive Sensing Layer 81 4.2.3 Strategy for Decoupling Deformation Modes 82 4.3 Fabrication Process 83 4.4 Characterization 83 4.4.1 Single-Mode Deformation . 84 4.4.2 Multi-Mode Deformation 86 4.5 Application . 87 4.6 Summary and Discussion 90 5 Conclusion 92 5.1 Thesis Summary . 92 5.2 Future Research 94 Abstract (In Korean) 98 Acknowlegement 101 vi박

제일인산칼륨과 벤토나이트의 TNT/중금속 이동제어 작용을 이용한 운영 중 사격장 위해도 관리

학위논문 (박사)-- 서울대학교 대학원 : 건설환경공학부, 2014. 2. 남경필.however, the leachable fraction decreased to 10% of initial TNT when bentonite was also amended with MKP. When the amount of bentonite was higher than 10% of initial TNT, the increase in the amended amount of bentonite did not reduce the leachability of TNT, indicating that MKP and bentonite application at 5% and 10% of soil mass is the optimal condition for the minimizing the mobility of TNT. At last, the risk reduction for the nearby residents of Darakdae firing range through the mobility reduction of TNT and heavy metals was quantified. The nearby residents of Darakdae firing range may use the Hantan River for the extraction of potable (drinking) and showering/bathing water. For the risk evaluation, carcinogenic and noncarcinogenic risk assessments were conducted. Furthermore, because of the great migration of contaminants from the firing range in summer due to the heavy rainfall, a monthly risk evaluation was conducted. The most significant contributors to the carcinogenic risk and noncarcinogenic hazard index were hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a type of explosive, and TNT, respectively. Even MKP/bentonite application could not reduce the mobility of RDX, the carcinogenic risk was acceptable ( 1) due to the migration of TNT in February, July and August. However, it was estimated that the noncarcinogenic hazard index could be reduced less than 1 by MKP/bentonite amendment. Thus, it can be concluded that MKP/bentonite application can reduce the risk to the local residents of the firing range by reducing the mobility of contaminants, especially TNT, released from the firing range.Recently, firing range contamination has become an emerging environmental issue in Korea. The most critical aspect of firing range contamination is the migration of contaminants from firing ranges to nearby surface water and/or groundwater, which is used as a source of drinking water for local residents. The soils at the firing ranges usually contain divalent cationic heavy metals (e.g., Pb2+, Cu2+, Zn2+, and Cd2+) and explosives, released from unexploded ordnances (UXOs) and shells. Of the explosives, 2,4,6-trinitrotoluene (TNT) is a typical concern due to its high toxicity and carcinogenicity. Thus, the mobility control of TNT and the divalent cationic heavy metals is important for the environmental management of the active firing ranges. It is known that K+ and PO43- can reduce the mobility of TNT and heavy metals via the specific sorption enhancement of TNT to clay mineral surfaces and heavy metals precipitation, respectively. Therefore, theoretically, monopotassium phosphate (MKP, KH2PO4), which contains both K+ and PO43-, can reduce the mobility of both TNT and heavy metals simultaneously and this study identified whether or not MKP can reduce the mobility of both TNT and heavy metals in soils collected from an active firing range, Darakdae firing range, located in Yeoncheon-gun, Gyeonggi Province, Korea. Mobility control of heavy metals using phosphate has been widely investigated and the lab-scale and field-scale feasibility study of phosphate application has been widely conducted. On the other hand, no studies on the feasibility of potassium application for the mobility control of TNT in soil are available at the present time. The earlier studies on the sorption enhancement of TNT by K+ conducted using K+-saturated soil and have focused on the identification of the specific sorption mechanism only. For this, at first, it was identified that whether or not MKP application can enhance the specific sorption, and which specific sorption mechanism is dominant between n-π electron donor-acceptor (EDA) interaction and cation-polar interaction. In untreated soil, TNT was not specifically sorbed to soil but MKP application induced the specific sorption of TNT, which resulting in the TNT sorption enhancement. Also, it was identified that the mechanism of specific sorption was a cation-polar interaction. Then, the simultaneous mobility reduction of TNT and heavy metals in soil by MKP application was studied. The mobility reduction was identified through synthetic precipitate leaching procedure (SPLP), and the leachability of TNT and heavy metals were greatly reduced by MKP application. It seems that mobility reduction is due to the sorption enhancement of TNT and heavy metals precipitation. The MKP application increased the sorption coefficient of TNT from 6.6 mg1-n kg-1 Ln to 12.1 mg1-n kg-1 Ln, and Pb, one of the concerned heavy metals in the firing range soil, was precipitated from soil. Finally, the mobility reduction of TNT and heavy metals was further elucidated using cyclodextrin and sequential extraction test, respectively, and both tests results revealed that the extractability of TNT and heavy metals decreased greatly (i.e., mobility of TNT and heavy metals greatly decreased). This study also investigated the minimizing mobility of TNT by MKP application with bentonite by further enhancement of TNT sorption. The leachable fraction determined by SPLP was about 50% of initial TNT when only MKP was amended with 5% of soil mass (the maximum soluble amount of MKP in porewater when the soil moisture content is the maximum water holding capacity)CHAPTER 1. INTRODUCTION 1 1.1 Background 1 1.2 Objectives 5 1.3 Dissertation Structure 6 References 7 CHAPTER 2. LITERATURE REVIEW 12 2.1 Existing Technologies for TNT Treatment in Firing Range Soil 12 2.1.1 Environmental behavior of TNT in firing range soil 12 2.1.2 Existing treatment technologies of TNT in firing range soil 16 2.2 Mechanism of Sorption of TNT onto Clay Mineral Surfaces 21 2.2.1 n-π EDA complexation 21 2.2.2 Cation-polar interaction 28 2.3 Role of Phosphate Ion on the Precipitation of Divalent Cationic Heavy Metals in Soil 34 2.3.1 Formation of heavy metal phosphate 34 2.3.2 Mobility and bioavailability reduction by heavy metal phosphate formation 35 2.3.3 Identification of heavy metal phosphate 40 References 43 CHAPTER 3. SORPTION ENHANCEMENT OF TNT IN SOIL BY MKP APPLICATION 54 3.1 Introduction 54 3.2 Experimental 57 3.2.1 Materials 57 3.2.2 Identification of sorption enhancement of TNT by MKP 59 3.2.3 Sorption test of TNT varying the aqueous Ca2+ concentration 62 3.2.4 Sorption test of TNT varying the aqueous 2,4-DNT or HFB concentration 62 3.2.5 Analysis 63 3.3 Results and Discussion 63 3.3.1 Clay mineralogy of the soil 63 3.3.2 Sorption enhancement of TNT by MKP 66 3.3.3 Role of Ca2+ in TNT sorption 69 3.3.4 Competitive sorption of TNT with HFB or 2,4-DNT 70 3.4 Summary 73 References 74 CHAPTER 4. DUAL MODE EFFECT OF MKP IN TNT SORPTION ENHANCEMENT AND HEAVY METALS PRECIPITATION 80 4.1 Introduction 80 4.2 Experimental 82 4.2.1 Materials 82 4.2.2 Simultaneous TNT sorption enhancement and Pb precipitation by MKP application 83 4.2.3 Quantification of mobility reduction of both TNT and heavy metals by MKP application using leach and extraction tests 86 4.2.4 Analysis 88 4.3 Results and Discussion 89 4.3.1 Simultaneous TNT sorption enhancement and Pb precipitation by MKP application 89 4.3.2 Identification of the type of lead phosphate formed by MKP application 93 4.3.3 Mobility reduction of TNT and heavy metals by MKP application 98 4.4 Summary 107 References 108 CHAPTER 5. MINIMIZING THE MOBILITY OF TNT BY BENTONITE AMENDMENT WITH MKP 113 5.1 Introduction 113 5.2 Experimental 114 5.2.1 Materials 114 5.2.2 Sorption and desorption test of TNT 115 5.2.3 Quantification of mobility reduction of TNT by MKP/bentonite application using leach and extraction tests 116 5.2.4 Analysis 119 5.3 Results and Discussion 119 5.3.1 Sorption enhancement of TNT by MKP/bentonite application 119 5.3.2 Change in the desorptive behavior of TNT by MKP/bentonite amendment 121 5.3.3 Minimizing the mobility of TNT by bentonite amendment with MKP 128 5.4 Summary 131 References 132 CHAPTER 6. RISK EVALUATION OF MKP/BENTONITE TREATMENT SCENARIO 136 6.1 Introduction 136 6.2 Development of the Conceptual Model of the Firing Range 138 6.2.1 Site description and exposure pathway 138 6.2.2 Contaminants concentrations in the Firing Range soil 139 6.2.3 Estimation of contaminants concentrations in the river 144 6.3 Exposure Assessment 155 6.3 Toxicity Assessment 162 6.4 Risk Characterization 164 6.5 Summary 174 References 176 CHAPTER 7. CONCLUSIONS 182 ANNEX A SITE INSPECTION RESULTS OF THE FIRING RANGE 186 ANNEX B STATISTICAL INFORMATION AND DERIVED (1-α)100% UPPER CONFIDENCE LIMIT ON THE MEAN (UCL) OF CONTAMINANTS IN THE FIRING RANGE SOILS 196 ANNEX C THE METEOROLOGICAL VALUES FOR THE DETERMINATION OF THE DEPTH OF SURFACE (DSR) AND GROUNDWATER RUNOFF (DGR) USING SEVIEW SOFTWARE 200 ANNEX D PROCEDURE FOR THE DETERMINATION OF INPUT VALUES ON THE PARAMETERS FOR THE CALCULATION OF INTAKE AND DERMAL ABSORBED DOSE 203 초 록 208Docto

Field emission characteristics of AlN film synthesized by a reactive magnetron sputtering process

Maste

분산 메인 메모리 컬럼 데이터베이스에서의 K-means 알고리즘 구현

학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2013. 2. 차상균.여러 분야에서 다루는 데이터의 크기는 지속적으로 증가하는 추세이며 이런 대용량 데이터에 대해 효율적으로 데이터마이닝 기법을 적용하고자 하는 요구가 증가하고 있다. Hadoop과 같은 분산프레임웍을 이용하면 대용량 데이터를 다룰 수 있지만 인터페이스의 한계 등으로 최적의 성능을 얻기는 어렵다. 분산 메인 메모리 컬럼 데이터베이스를 이용할 경우 분산환경에서 대용량 데이터를 관리하기에 용이하고 메인 메모리 환경에서 빠른 연산이 가능하지만 분산 및 메인 메모리 환경을 제대로 활용한 데이터마이닝 구현은 제대로 제공하지 못하고 있다. 본 논문에서는 분산 메인 메모리 컬럼 데이터베이스 환경에서 대용량 데이터에 대해 효율적으로 K-means 알고리즘을 적용하는 방안을 모색하였다. 컬럼 테이블에 저장된 데이터를 효율적으로 이용하기 위해 컬럼 테이블에 적합한 K-means 알고리즘을 제안하였으며 stored procedure 및 내부 API를 이용하여 데이터 접근 및 분산환경에서의 데이터 동기화 과정을 빠르게 처리할 수 있게 구현하였다. 데이터는 partitioned 컬럼 테이블을 이용해 각 노드에 분산저장하며 내부 API를 통해 각 노드 간 데이터 동기화 과정을 효율적으로 처리하였다. 각 노드에서는 내부 API를 통해 할당된 partition에만 빠르게 접근하여 locality 정보를 살려 데이터 intensive한 계산과정을 수행하도록 하였다. 컬럼 테이블에 저장된 데이터에 대해 효율적으로 K-means를 적용하기 위해 dictionary encoding 및 inverted index를 이용해 컬럼 단위로 계산을 수행하는 알고리즘을 제안하였다. 위에서 언급한 내용을 바탕으로 데이터마이닝 알고리즘 중 잘 알려진 K-means 알고리즘(KM)과 triangle inequality를 이용한 optimized version의 K-means 알고리즘(EKM)을 분산 메인 메모리 컬럼 데이터베이스 상에서 구현하였다. 구현한 알고리즘의 scalability를 확인한 결과 데이터, 클러스터, 노드 등의 개수에 대해 linear scalability를 보였다. 분산환경에서 Hadoop과 성능을 비교한 결과 8배 정도의 성능 향상을 보였다. 또한 컬럼 테이블에 저장된 데이터를 더 효율적으로 처리할 수 있는 K-means 알고리즘(CEKM)을 구현하여 컬럼 테이블에서 효율적인 K-means 알고리즘의 적용이 가능함을 확인하였다.초록 i 목차 iii 제 1 장 서론 １ 1.1 연구 배경 １ 1.2 문제 정의 ２ 1.3 연구 목표 및 접근 방법 ３ 1.4 연구 결과 요약 ４ 1.5 논문 구성 ５ 제 2 장 배경 지식 및 관련 연구 ６ 2.1 분산 데이터베이스 및 분산 데이터마이닝 ６ 2.2 아파치 마하웃 (Apache Mahout) ７ 2.3 관련연구 ７ 제 3 장 Internal 데이터베이스 레벨에서의 K-means의 구현 ９ 3.1 접근방법 ９ 3.2 구현 １１ 3.2.1 데이터 저장 형식 １１ 3.2.2 데이터에의 접근방법 １２ 3.2.3 K-means 알고리즘의 수행 １４ 3.2.4 노드 간 데이터 통신 제어 １８ 제 4 장 컬럼 테이블 상에서의 K-means 알고리즘의 최적화 ２１ 4.1 접근방법 ２１ 4.2 구현 ２２ 4.2.1 Attribute 단위의 거리 계산 ２２ 4.2.2 Dictionary 및 inverted index를 이용한 구현 ２５ 4.2.3 삼각부등식을 이용한 거리 계산 생략 과정 ２７ 제 5 장 실험 및 결과 ３０ 5.1 C++ 및 stored procedure에서의 EKM 성능 ３０ 5.2 K-means 알고리즘의 scalability ３１ 5.3 Hadoop상에서의 구현과의 비교 ３４ 5.4 CEKM의 성능평가 ３６ 제 6 장 결론 및 향후 현구 ３８ 참고문헌 ４０ ABSTRACT ４２Maste

FOXO3a controls vascular smooth muscle cells proliferation through modulation of an angiogenic immediate early gene, CYR61

Thesis(master`s)--서울대학교 대학원 :의학과 분자유전체의학전공,2006.Maste

3D 그래픽스 응용을 위한 데이터 플로우 모델의 확장

학위논문(석사)--서울대학교 대학원 :컴퓨터공학과,2000.Maste