방사 무선전력전송을 위한 무지향성 안테나 및 전송 효율 한계에 대한 연구

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 전기·정보공학부, 2020. 8. 남상욱.본 논문에는 방사하는 전자파를 이용한 무선 전력 전송에 대해 집중적으로 연구를 진행하였다. 보다 구체적으로는, 무지향성 안테나의 분석과 설계, 자유공간과 손실매질에서의 최적 송신 전류 분포, 전송 효율의 한계에 대한 연구를 기술하였다. 추가적으로, 전자파의 인체 영향에 대한 비교 및 이론적인 최적 전류 분포의 효과적 구현에 대한 연구를 진행하였다. 본 연구에서는 방사형 무선전력전송을 전원을 공급 유무에 따라 수동형과 능동형 무선전력전송으로 구분하고, 수동형 방사 무선전력전송부터 능동형 방사 무선전력전송까지의 연구를 순차적으로 기술하였다. 먼저, 수동형 방사 무선전력전송 연구에서는 전자파 에너지 하베스팅용 안테나에 대한 분석 및 설계에 대한 연구를 진행하였다. 수동 방사 무선전력전송의 상황을 고려하여 등방성 패턴, 전기적으로 작은 크기, 높은 효율 특성을 나타내는 안테나를 제안하였다. 전기적으로 소형이면서 등방성 패턴을 방사하는 SRR이 기본 구조로 활용되었다. SRR에 대한 이론적 분석을 진행하였고, 시뮬레이션 결과와 잘 맞는 것을 확인하였다. 분석에 기초하여 FSRR 안테나를 설계하였고, 측정을 통해 제안한 아이디어를 검증하였다. 수신 파워의 크기를 향상시키기 위해, 이중 대역 및 확장된 대역에서 동작하는 FSRR 안테나를 추가로 설계하였다. 제안된 구조는 선행연구와 비교하였을 때, 상대적으로 우수한 성능을 보여주었다. 한편 수동형 방사 무선 전력전송의 경우, 주변의 낮은 전력 밀도로 인해 수신 전력이 매우 낮은 한계점이 존재한다. 따라서, 송신 타워를 이용해 모바일 안테나로 무선 전력을 전송할 수 있는 능동형 방사 무선전력전송에 대한 후속 연구를 진행하였다. 능동형 방사 무선전력전송에서는, 송신 타워를 활용하여 모바일 기기에 효과적으로 무선전력전송을 수행하는 방법에 대한 연구를 진행하였다. 본 연구에서는 방사형 무선전력전송의 효율을 최대화 하는 송신 전류분포와 주어진 면적을 활용할 때 얻을 수 있는 최대 한계 효율을 이론적으로 도출하였다. 본 연구의 결과를 통해, 기존의 방식으로는 파악할 수 없었던 중거리 무선전력전송 효율의 최대 한계치와 송신 전류분포의 최적 형태를 파악할 수 있다. 연구의 결론에 따르면, 수신하는 안테나의 송신 방사 패턴이 효율을 결정함에 있어 중요한 역할을 하였다. 제안한 이론을 실제 안테나에 적용하여 선행연구와 비교를 하였고, 선행 연구로 파악할 수 없는 이론적 한계 효율을 도출하였다. 제안한 연구를 일반적인 상황으로 확장하기 위해 손실 매질 내부에서의 무선전력전송에 대한 추가 연구를 진행하였다. 손실 매질이 있는 경우에서도 최적 전류 분포와 효율의 최대 한계치를 도출하였다. 최적 송신 전류를 활용하여, 실제 안테나 어레이를 구현하고 인체 팬텀에 미치는 영향을 파악해보았다. 마지막으로, 앞서 도출한 이론적인 전류분포를 실제 안테나로 구현하는 방법에 대해 연구를 진행하였다. 선행 연구를 참고하여, 이상적인 전류분포를 thinned 배열로 구현하는 두가지 방법을 제안하였다. 이론적인 전류 분포에 유전 알고리즘을 활용한 방법과, density tapering을 응용한 방법을 적용하였다. 두 방법 모두 동일한 개수의 균등 어레이에 비해 성능이 개선되는 결과를 보였다. 특히 density tapering을 이용하면 같은 개수 및 같은 면적의 격자구조보다 비용, 무게, 효율 등에서 장점이 있으며, 수신기의 위치가 변할 때에도 더 높은 효율로 송신이 가능하다.In this thesis, research on the radiative-wireless power transmission (R-WPT) using radiated electromagnetic(EM) fields is presented. More specifically, the analysis and design of quasi-isotropic antennas, the analytical study on the optimal transmitting current, and the efficiency bounds are described. In addition, research on the comparison of the EM effects on the human phantom, and the effective implementation of the optimal current distribution are conducted. The research is described sequentially from the passive R-WPT to active R-WPT, which indicate the absence or presence of the power supplying base station. First, research is conducted on the analysis and design of the passive R-WPT antenna. Considering the ambient environment, an antenna with quasi-isotropic pattern, electrically small size, and high efficiency is proposed. A split-ring resonator (SRR) that radiate quasi-isotropic pattern with electrically small size is used as a basic structure. The analysis on the SRR is well matched with the simulation results. Based on the analysis, folded split-ring resonator (FSRR) is proposed and designed for the passive R-WPT antennas, and verified through the measurement. A dualband and wideband FSRR that can harvest more ambient power is designed as an extended work. The proposed antennas are compared with recent studies showing superior performances. On the other hand, the receiving power of the passive R-WPT is very low due to low power density of ambient field, a study on the active R-WPT, which can transfer wireless powers from the base station to the mobile antenna, is conducted as a next step. In the active R-WPT, a study on the way to effectively transfer wireless power to the mobile devices by using a transmitting tower is described. The optimal current distribution of the transmitting surface, and maximum power transfer efficiency (PTE) bounds when the transmitting area is limited are analytically derived. Through the results, it is possible to figure out the maximum efficiency bounds for the mid-range R-WPT and the optimal shape of transmission current distribution that could not be found by the conventional method. The results indicate that the optimum current distribution on the transmitting surface and the maximum efficiency of radiative WPT depend on the radiating field pattern of the mobile antenna. To generalize the proposed theory, an additional analysis in lossy environment is carried out. The optimal transmitting current and efficiency bound in lossy media is found for a couple of examples. The results are compared with the previous works to verify the proposed theory. Based on the results in lossy media, the EM effects on the human body is investigated. Lastly, research on the effective implementation of the theoretical current distribution as practical antenna arrays is described. Based on the previous research, two techniques that can effectively realize the ideal current are proposed in designing a thinned array. An optimization using genetic algorithm, and deterministic density tapering are applied to sample the theoretical current distribution. As a results, the proposed thinned arrays show improved performance compared to the same number of densely arranged regular arrays. In particular, the use of density tapering has advantages in cost, weight, efficiency than the same number of the regular array. In addition, it is possible to transmit wireless power with better efficiency even when the position of the receiver changes.Chapter 1. Introduction 1 1.1. Classification of Wireless Power Transmission 1 1.2. Separation of Regions 3 1.3. Passive and Active Radiative-Wireless Power Transmission 6 1.4. References 14 Chapter 2. Passive: RF Energy Harvesting Antenna 18 2.1. Motivation 18 2.2. Analytical Study on RF Energy Harvesting Antenna 19 2.2.1. Previous Research 19 2.2.2. Analysis on Split-Ring Resonator 21 2.2.3. Analysis on the Symmetric Folded Split-Ring Resonator 25 2.2.4. Analysis on the Asymmetric Folded Split-Ring Resonator 30 2.3. Design of RF Energy Harvesting Antenna 34 2.3.1. Antenna Design 37 2.3.2 Results and Discussion 44 2.4. Design of RF Energy Harvesting Antenna with Dual-band Operation 45 2.4.1. Motivation 45 2.4.2 Antenna Design 45 2.4.3. Results and Discussion 48 2.5. RF Energy Harvesting Antenna with Wide-band Operation 53 2.5.1. Motivation 53 2.5.2 Antenna Design 54 2.5.3. Results and Discussion 57 2.6. Conclusion 65 2.7. References 69 Chapter 3. Active: Radiative-WPT in Lossless Medium 73 3.1. Motivation 73 3.2. Previous Research 73 3.3. Theoretical Approach 77 3.3.1. Power Transfer Efficiency 77 3.3.2. Optimum Transmitting Current 80 3.3.3. Minimizing Transmitting Area 84 3.4. Numerical Examples 86 3.3.1. Dipole Antenna 88 3.3.2. Patch Antenna 90 3.3.3. Horn Antenna 91 3.5. Results and Discussion 93 3.5. Conclusion 98 3.6. References 99 Chapter 4. Active: Radiative-WPT in Lossy Media 103 4.1. Motivation 103 4.2. Previous Research 103 4.3. Theoretical Approach 106 4.3.1. Problem Formulation 108 4.3.2. Maximum Power Transfer Efficiency 110 4.4. Practical Examples 114 4.4.1. Planar Inverted-F Antenna 116 4.4.2. Half-Mode Cavity-Backed Antenna 120 4.5. Electromagnetic Human Exposure in Radiative WPT System 125 4.5.1. Motivation 125 4.5.2. Simulation Results 126 4.6. Conclusion 132 4.7. References 134 Chapter 5. Active: Implementation of Optimal Transmitting Current Distribution 138 5.1. Motivation 138 5.2. Theoretical Approach 139 5.2.1. Radiation Pattern Matching 139 5.2.2. Optimal Excitation Coefficient 141 5.2.3. Thinning of Transmitting Array 141 5.3. Implementation of the Optimal Current Sheet 145 5.3.1. Array Thinning using Genetic Algorithm 145 5.3.2. Results and Discussions 148 5.3.3. Array Thinning using Density Tapering 151 5.3.4. Results and Discussions 154 5.4. Conclusion 158 5.5. References 159Docto

The effects of eudurance exercise on expressionof myokines and tumor tissue in colon cancer-induced mice

학위논문 (박사)-- 서울대학교 대학원 : 체육교육과, 2014. 2. 전태원.A few studies have demonstrated that exercise induces the release of cytokines from contracting muscles. These muscle-derived cytokines are collectively named myokines. Skeletal muscle is the largest organ in the human body, as an endocrine organ, muscle tissue has had a central role in orchestrating metabolism of other organs. The researchers have found a link between muscle contraction and these myokines in the form of an exercise factor. Recently accumulating evidence indicated that myokines may also play a role in cancer protection. It was shown that the contracting muscle by an acute exercise release humoral factors such as OSM, IL-10, SPARC that can inhibit cancer cell proliferation and induce cancer cell apoptosis. Base on the prevailing literature, the purpose of the present study was to investigate the impact of long-term exercise on expression of cytokines in muscle, blood and tumor tissue, thus to examine whether exercise mediates independent protective effect against cancer through the release of anti-proliferative proteins from contracting muscles according to exercise intensity. First, to identify the therapeutic effect of exercise, all mice at 6-wk old were injected AOM and were treated 3 cycles of DSS solution in drinking water to induce colon cancer. Then at 17-wk of old, mice of exercise groups performed treadmill exercise at different intensity (Low, Moderate, High) for 30 minutes, 5 days per week, during 12 weeks. Twenty-four hours after the last training session, all tissues were removed and blood samples were obtained. To analysis the effect of exercise, OSM and SPARC were evaluated in muscle, serum, and tumor tissue. Also related pro-apoptosis factor, caspase-3 in tumor tissue were analyzed. OSM was significantly overexpressed in exercise groups compare to controlsin gastrocnemius (p=.000), serum (p=.005), and tumor tissue (p=.000). Also, there was significant differences among exercise groups by exercise intensity on expression of OSM in colon-induced mice. The expression of OSM tends to increase in higher intensity in gastrocnemius (p=.000)LIE (p= .014), MIE (p=.000), HIE (p=.000), in tumor tissue (p=.000)LIE (p= .000), MIE (p=.000), HIE (p=.000), but only in serum of LIE (p=.000). The level of SPARC was significantly increased by exercise in muscle (p=.000), serum (p=.002), tumor tissue (p=.001) compare to controls. Also the expression of SPARC tends to increase in higher intensity in gastrocnemius (p=.001)LIE (p= .035), MIE (p=.001), HIE (p=.007), in tumor tissue (p=.000)MIE (p=.000), HIE (p=.000). The expression of caspase-3 increased significantly in MIE (p=.045). Secondly, to identify the preventive effect of exercise on colon cancer-induced mice, mice of exercise groups, at 6-wk of old, performed exercise at different intensity (Low, Moderate, High) for 30 minutes, 5 days per week, during 12 weeks. At 17-wk of old, all mice were injected AOM and were given 3 cycles of DSS solution in drinking water to induce colon cancer. Then they kept doing exercise for another 12 weeks. The level of OSM in muscle was significantly overexpressed in exercise groups compare to controls, however, not in blood and tumor tissue (p>.05). Also, there was significant differences among exercise groups by exercise intensity on expression of OSM in muscle. The expression of LIE (p=.001) and MIE (p=.000) were significantly increased than controls. However, the expression of OSM in blood was not increased by exercise intensity (p>.05). In the same time, the level of OSM in tumor tissue tends to increase by exercise intensity, but there was no statistical difference (p>.05). The level of SPARC was significantly increased by exercise in blood (p=.002), tumor tissue (p=.001) compare with controls, however, there was no significant difference in muscle (p>.05). However, the expression of SPARC in MIE was significantly higher than CON in gastrocnemius (p=.010). Also the expression of SPARC in tumor tissue tends to increase significantly by exercise intensityMIE (p=.001), HIE (p=.000). Even though the expression of cleaved caspase-3 in tumor tissue tends to increase by exercise intensity, there was no statistical difference (p>.05). In conclusion, this study showed that exercise induced the expression of OSM and SPARC in several tissues by exercise stimulus, which is associated with inducing apoptosis in tumor cells. And the magnitude of OSM and SPARC induction in muscle and tumor tissue was relatively higher in moderate and high intensity exercise groups than low intensity exercise group. Moreover, moderate and high intensity exercise enhanced anti-apoptotic pathway in skeletal muscle, and increased gastrocnemius muscle weight. In addition, it is observed that the number of polyp generation in moderate and high intensity exercise group was significantly decreased than controls. Thus, the results of this study possibly suggest that moderate and high intensity exercise have more protective effect for colon cancer induced mice.CONTENTS ABSTRACT i CONTENTS iv LIST OF TABLES vi LIST OF FIGURES vii LIST OF ABBREVIATIONS ix I. INTRODUCTION 1 II. LITERATURE REVIES 4 2.1. Cancer and physical activity 4 2.1.1. The incidence of cancer in Korea 4 2.1.2. Physical activity and colon cancer 5 2.2. Chronic inflammation-derived colon tumor mice 6 2.3. Myokines 8 2.3.1 Interleukin-6 9 2.3.2 Interluekin-8 10 2.3.3 Interluekin-15 11 2.4. Exercise-induced myokines in cancer cell 12 2.4.1. Oncostatin M 12 2.4.2. SPARC (Secreted protein acidic and rich in cysteine) 13 2.5. Apoptosis in colon cancer-induced mice 13 2.5.1. Mechanism of apoptosis 13 2.5.2. Caspase-3 in apoptosis 14 2.5.3. Muscle apoptosis in cancer model 15 2.5.4. Exercise effects on apoptosis in muscle 15 III. Material and Method 17 3.1. Animals and treatments 17 3.2. Experimental design 18 3.2.1. The first experiment 18 3.2.2. The second experiment 20 3.3. Exercise protocol 22 3.4. Tissue Collection 23 3.5. Polyp counts 23 3.6. Western blot 23 3.7. ELISA 24 3.8. Statistical analysis 24 IV. RESULTS 25 4.1. The first experiment 25 4.1.1. The change of body weight 25 4.1.2. Muscle weight 27 4.1.3. Colon weight 29 4.1.4. Polyp incidence 30 4.1.5. Correlation of muscle weight and polyp number 31 4.1.6. Muscle apoptosis 32 4.1.7. The expression of OSM 34 4.1.8. The expression of SPARC 38 4.1.9. The expression of caspase-3 in tumor tissue 42 4.2. The second experiment 43 4.2.1. Relative risk of premature mortality 43 4.2.2. The change of body weight 45 4.2.3. Muscle weight 46 4.2.4. Muscle apoptosis 48 4.2.5. The expression of OSM 50 4.2.6. The expression of SPARC 54 4.2.7. The expression of cleaved caspase-3 58 V. Discussion & Conclusion 59 REFERENCES 66 ABSTRACT IN KOREAN 74Docto

동축류 제트에서 부상화염의 진동 메커니즘에 관한 수치적 연구

Thesis (doctoral)--서울대학교 대학원 :기계항공공학부,2004.Docto

연료산화제의 2차원 혼합층에서 삼지화염의 전파 특성에 관한 수치해석

학위논문(석사)--서울대학교 대학원 :기계공학과,2000.Maste

막결합형 혐기성 소화시스템에서 막오염 감소를 위한 제올라이트의 응용에 관한 연구

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현대 한국사회의 입양관행으로 본 부부관계와 자녀의 의미

학위논문(석사) --서울대학교 대학원 :인류학과,2006.Maste

(The) Effect of Combined Exercise Program on Health-related Physical Fitness in Obese Middle-aged Women

학위논문(석사) --서울대학교 대학원 :체육교육과,2009.8.Maste

에이즈 캠페인에서 메시지의 설득적 효과에 영향을 미치는 요인

학위논문(석사) --서울대학교 보건대학원 :보건학과(보건정책관리학전공),2010.2.Maste