상보적인 스위치 동작을 이용한 주입 고정 위상 동기화 루프의 설계에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 전기·컴퓨터공학부, 2019. 2. 정덕균.높은 속도의 어플리케이션의 수요 증가로 인하여 좋은 성능의 높은 주파수 생성기의 요구가 증가하고 있다. 이에 따라 주입 고정 발진기를 이용한 연구가 활발히 진행되고 있다. 본 논문에서는 상보적인 스위치 동작을 이용한 주입 고정 위상 동기화 루프 (subharmonically injection-locked phase-locked loop) 의 설계에 관한 연구에 대해 논의한다. 설계의 간소화를 위하여 상보적인 스위치 동작을 이용한 주입방법 (complementary switched injection) 을 제안하고 서브샘플링 위상 검출기 (sub-sampling phase detector) 를 사용하였다. 스위치 동작을 이용한 주입방법은 펄스발생기를 대체함으로써 지연시간이 발생하지 않도록 하였고 주입 클락의 듀얼 엣지에서 주입이 가능하여 싱글 엣지 주입보다 성능이 좋아진다는 장점이 있다. 서브샘플링 위상 검출기 또한 위상 동기화 루프의 피드백 경로에서 지연시간이 발생하지 않기 때문에 추가적인 주입 타이밍 루프가 없어도 주입 경로와 위상 동기화 루프에서 위상이 조정될 때 서로간의 불일치가 발생하지 않는다. 또한, 제안된 구조의 주입 고정 위상 동기화 루프는 전압이나 온도에 덜 민감하게 설계되었다. 제안한 스위치 동작을 이용한 주입방법을 전하 이동을 기반으로 분석하였고 잘못된 타이밍에 주입이 되었을 때 레퍼런스 스퍼에 대한 성능을 비교하였다. 65-nm CMOS 공정을 이용하여 만들어진 칩은 5 GHz 에서 15.4 mW의 파워 소모와 0.06 mm2 의 면적을 가진다. 또한, 동작영역은 2.5 GHz 에서 5.6 GHz 를 가지며5 GHz 에서168 fs rms지터를 갖는다.As increasing demands for high speeds link systems and requiring design challenges in clock generation, the injection locking technique is widely used in clock multiplication. However, it is still difficult to design high performance of injection-locked clock multiplier (ILCM) because of its narrow lock-in range. In this thesis, a low-phase-noise subharmonically injection-locked sub-sampling all-digital phase-locked loop (ILPLL) is proposed using a dual-edge complementary switched injection (CSI) technique and sub-sampling bang-bang phase detector (SSBBPD) without an injection pulse generation and injection timing calibration circuitry. With the proposed IL-DCO and SSBBPD, the phase alignment mismatch between the PLL loop and injection path does not occurs and makes it possible to exhibit a simplified architecture. Because the CSI technique exploits dual-edge injection, the performance impact of dual-edge injection when inaccurate injection time occurs is analyzed. Also, the CSI technique is analyzed with base on the charge transfer and derives the realignment factor of the injection. With the CSI technique and the direct connection of the digitally controlled oscillator (DCO) clock to the SSBBPD, the timing mismatch between the PLL loop and injection path becomes less sensitive to voltage and temperature drift. The proposed ILPLL prototype is fabricated in a 65-nm CMOS process and achieves a 168-fs integrated RMS jitter over 1 kHz to 40 MHz at a 5-GHz output frequency with 156.25-MHz reference clock while consuming 15.4 mW with an active area of 0.06 mm2.ABSTRACT I CONTENTS III LIST OF FIGURES V LIST OF TABLES X CHAPTER 1 INTRODUCTION 11 1.1 MOTIVATION 11 1.2 THESIS ORGANIZATION 13 CHAPTER 2 BASIC INJECTION-LOCKED CLOCK MULTIPLIER 14 2.1 INJECTION-LOCKED OSCILLATOR (ILO) 14 2.1.1 INTRODUCTION 14 2.1.2 PHASE DOMAIN RESPONSE (PDR) ANALYSIS 21 2.1.3 NOISE FILTERING BANDWIDTH 30 2.2 INJECTION-LOCKED CLOCK MULTIPLIER 33 2.2.1 OVERVIEW 33 2.2.2 PRIOR ARTS 37 2.2.2.1 PLL-BASED ILCM 37 2.2.2.2 REPLICA-BASED ILCM 39 2.2.2.3 REAL-TIME FTL-BASED ILCM 41 2.3 CONCEPT OF THE PROPOSED ILCM 43 CHAPTER 3 DESIGN OF SUBHARMONICALLY ILPLL 44 3.1 OVERVIEW 44 3.2 PROPOSED ARCHITECTURE 45 3.2.1 OVERALL ARCHITECTURE 45 3.2.2 DUAL-EDGE COMPLEMENTARY SWITCHED INJECTION 47 3.3 ANALYSIS OF THE INJECTION-LOCKED PLL 55 3.3.1 NOISE ANALYSIS 55 3.3.2 PHASE MARGIN ANALYSIS 60 3.3.3 SPUR ANALYSIS 64 3.4 CIRCUIT IMPLEMENTATION 75 3.4.1 DIGITALLY CONTROLLED ILO 75 3.4.2 SSBBPD AND FRONT-END 76 3.4.3 FREQUENCY DETECTOR 82 CHAPTER 4 MEASUREMENT 86 CHAPTER 5 CONCLUSION 97 APPENDIX A 98 BIBLIOGRAPHY 105 초 록 113Docto

Treatment of Simple Renal Cysts by Percutaneous Aspiration and OK-432 Sclerotherapy

PURPOSE: Percutaneous aspiration with sclerotherapy has been widely used for the treatment of symptomatic or large simple renal cysts. Ethanol has been most commonly used as a sclerosing agent; however, a temporary percutaneous nephrostomy for multiple ethanol injections is necessary to achieve a low recurrence rate. Thus, we used OK-432 as a new sclerosing agent without a temporary percutaneous nephrostomy for multiple injections, and also compared our results with the results of previous studies. MATERIALS AND METHDOS: Between October 2005 and April 2006, 50 patients (63 simple renal cysts) who underwent percutaneous OK-432 sclerotherapy for simple renal cysts were evaluated. The simple renal cysts were aspirated under ultrasonography and fluoroscopy, after which OK-432 was injected into the cyst. Follow-up was performed with ultrasonography or CT scan after 3 months. Regression of the renal cyst or a >70% reduction in size with no symptoms was considered a treatment success. RESULTS: Among 63 renal cysts in 50 patients, complete regression occurred in 17(27.0%). Greater than a 90% reduction in size occurred in 8(12.7%), a 80-90% reduction in size occurred in 21(33.3%), and a 70-80% reduction in size occurred in 15(23.8%); a <70% reduction in size occurred in 2 (3%). The overall efficacies of success were 96.8%. After the procedure, there were only some minor complications, such as mild fever, local pain, and liver function test elevation that subsided with symptomatic treatment. CONCLUSIONS: Percutaneous OK-432 sclerotherapy is simple, safe, and effective and can be an alternative first-line therapy of simple renal cysts.ope

Prognostic impact of peripelvic fat invasion in pT3 renal pelvic transitional cell carcinoma

Renal pelvic transitional cell carcinoma (TCC), which invades beyond muscularis into peripelvic fat or the renal parenchyma, is diagnosed as stage pT3 despite its structural complexity. We evaluated the prognostic impact of peripelvic fat invasion in pT3 renal pelvic TCC. Between 1986 and 2004, the medical records on 128 patients who were surgically treated for renal pelvic TCC were retrospectively reviewed. Sixty patients with pT3 disease were eligible for the main analysis. The prognostic impact of various clinicopathological factors was analyzed using univariate and multivariate analyses. On univariate analysis, sex, age, concomitant bladder tumors, concomitant ureter tumors, lymphadenectomy, adjuvant chemotherapy, tumor grade, multiplicity, renal parenchymal invasion, and carcinoma in situ did not influence the disease-specific survival (p>0.05). By contrast, peripelvic fat invasion, lymph node invasion, and lymphovascular invasion were each significantly associated with disease-specific survival (p<0.05). Multivariate analysis showed that peripelvic fat invasion (p=0.012) and lymph node invasion (p=0.004) were independent prognostic factors. In conclusion, peripelvic fat invasion is a strong prognostic factor in pT3 renal pelvic TCC. Thus, systemic adjuvant therapy should be considered in the presence of peripelvic fat invasion, even if the lymph nodes are not involved.ope

(The) effect of pathologic tumor density on biochemical recurrence after radical prostatectomy

의학과/석사[한글] 연구목적: 술후 병리조직에서 계산된 전립선암 용적은 생화학적 재발의 독립적 위험인자로서 알려져 왔다. 그러나 전립선의 크기는 암의 유무와 관련없이 개인의 상태에 따라 다를 수 있다. 따라서 전립선 크기를 고려한 종양밀도가 생화학적 재발에 미치는 영향을 알아보고자 하였다. 연구방법: 1996년 5월부터 2005년 4월까지 본원에서 전립선암으로 근치적 전립선 절제술을 시행받은 환자 중 술전 호르몬 치료를 시행받거나 암의 용적이 술 후 측정되지 못한 환자를 제외한 251명을 대상으로 하였다. 전립선용적은 병리소견에서 보고된 무게를 용적으로 환산하여 이용하였으며 암의 용적은 병리조직에서 전체조직을 Stanford protocol을 이용하여 컴퓨터로 계산되었다. 생화학적 재발의 위험인자로 알려진 인자들을 포함하여 암용적과 종양밀도를 단변량 분석을 이용하여 무병생존기간에 미치는 영향을 분석하였으며 의미있게 나온 인자들로 다변량 분석을 시도하였다. 결과: 단변량 분석에서 무병생존기간에 유의한 위험인자들로는 PSA 10ng/ml이상 (p < 0.009), 암용적 5cc이상 (p < 0.010), 종양밀도 10%이상 (p < 0.007), 피막침범유무 (p = 0.009), 림프절침범유무(p = 0.008), 외과적 경계 침범유무(p = 0.000), 정낭침범 유무였다 (p = 0.032). 단변량 분석에서 유의한 위험인자들로 시행된 다변량 분석에서 외과적 경계 침범유무와 (비교위험도 = 3.066, p = 0.000) 종양밀도 10%이상이 생화학적 재발과 무병생존기간에 의미있는 위험인자로 나타났다 (비교위험도 = 1.991, p = 0.026). 이는 종양밀도를 인자로서 제외하였을 때 외과적 경계 침범유무와 (비교위험도 = 3.099, p = 0.000) 암용적 5cc이상으로 나타났을 때와 차이를 보였다 (비교위험도 = 2.032, p = 0.033). 결론: 종양밀도는 암용적 단독에 비해 상위의 생화학적 재발의 위험인자로 고려되어야 할 것으로 생각된다. [영문]Purpose: Prostate cancer volume, which is calculated from pathological tissue after the operation, has been known as an independent risk factor of biochemical recurrence. However, it is possible that the size of prostate depends on individual state regardless of the existence of cancer. Therefore, we evaluated the effect of tumor density reflecting the size of prostate on biochemical recurrence. Patients and Methods: 251 patients were selected for the study. They underwent radical prostatectomy for prostate cancer in our hospital from May, 1996 to April, 2005 and did not recieve neoadjuvant treatment before the operation. The size of the cancer in each patient was clearly measured. We calculated the size of the prostate by converting the weight reported in pathologic finding and the size of the cancer by computer using stanford protocol of whole specimen. We analyzed the effect on disease free survival time using univariate analysis of factors of tumor volume and tumor density including risk factors of biochemical recurrence. We also tried to perform the multivariate analysis of the factors which was considered critical in univariate analysis. Results: The univariate analysis showed that critical risk factors of disease free survival time were over 10ng/ml of PSA (p < 0.009), over 5cc of tumor volume (p < 0.010), over 10% in tumor density (p < 0.007), capsular invasion (p = 0.009), lymph node invasion (p = 0.008), positive surgical margin (p = 0.000), and seminal vesicle invasion (p = 0.032). positive surgical margin (relative risk = 3.066, p = 0.000) and over 10% in tumor density were also considered critical risk factors of biochemical recurrence and disease free survival time in multivariate analysis which was performed with risk factors considered in uniivariate analysis. If excluding tumor density as a risk factor for biochemical recurrence, time to biochemical recurrence was significantly shorter in patients with positive surgical margin (relative risk = 3.099, p = 0.000), and tumor volume greater than 5cc (relative risk = 2.032, p = 0.033) than in those without. Conclusion: Tumor density should be more critical risk factor of biochemical recurrence than the volume of cancer.ope

[특집] 기업에서 인적자원개발의 의미

본고에서는 21세기 경영환경 변화에 따라 기업이 추구해야 할 새로운 생존전략으로써 인재육성에 더욱 많은 노력을 하여야 하는 이유를 살펴 보고자 한다

Time-dependent Deterioration in Erectile Function and Its Relation with Penile Histologic and Molecular Changes in Streptozotocin-induced Diabetic Rats

학위논문(석사) --서울대학교 대학원 :의학과(비뇨기과학전공),2010.2.Maste

Investigation of the Effects of the Level of Glycemic Control on Erectile Function and Pathophysiological Mechanisms in Diabetic Rats

목적: 당뇨병은 단일 질환으로 발기부전의 가장 흔한 원인이며, 당뇨병성 발기부전은 표준 치료법에 잘 반응하지 않는 난치성 질환으로 알려져 있다. 지금까지 당뇨병성 발기부전의 발생에 관여하는 다양한 병태생리학적 기전들이 제시된 바 있으나 혈당 조절의 정도에 따른 발기력의 변화에 대한 연구는 전무한 실정이다. 임상적으로 발기부전의 유병률과 심한 정도는 혈당의 조절상태와 당뇨병의 유병기간과 밀접한 관련성을 지닌다. 실험적으로는 인슐린이 혈당의 조절뿐만 아니라 발기현상에 있어 핵심적인 역할을 담당하는 nitric oxide의 활성을 증가시키는 것으로 알려져 있다. 그러므로 본 연구에서는 당뇨병 유발 백서에서 인슐린을 이용하여 혈당 조절 정도를 차등화 하였을 때 나타나는 발기력의 변화를 관찰하고 이에 따른 음경해면체의 구조적, 기능적 변화를 조사하여 당뇨병성 발기부전의 병태생리학적 기전 규명에 있어 가장 핵심적인 기초 지식을 제공해 줄 것이다. 대상 및 방법: 8주령 수컷 백서 55마리를 정상 대조군과 당뇨병군으로 무작위 배정 후 당뇨병군의 백서는 streptozotocin의 복강 내 주사로 당뇨병을 유발하였다. 연구자의 선행 연구를 통하여 발기력의 뚜렷한 저하가 관찰되는 시점인 당뇨병 유발 후 10주째에 정상대조군 (1군, 10마리), 엄격한 혈당 조절군 (2군, 15마리), 불량한 혈당 조절군 (3군, 15마리), 비치료 당뇨병군 (4군, 15마리)으로 다시 무작위 배정하였다. 이후 4주 동안 인슐린 투여를 통하여 혈당 조절 목표를 달성한 이후 혈당 조절 정도에 따른 발기력의 변화를 조사하였다. 발기력의 평가는 해면체신경 전기자극에 대한 해면체내압측정술로 이루어졌으며, 측정된 해면체내압은 평균동맥압으로 보정하였다. 해면체내압측정술을 통하여 주파수-의존적 내압 변화, 해면체내압 반응곡선의 AUC (area under the curve), 최대 반응 도달 시간 등 다양한 생리학적 지표를 도출하였다. 발기반응의 생리학적 지표들은 당화혈색소 (HbA1c)의 수치로 대변되는 혈당 조절의 정도와 비교하였다. 면역화학염색을 통하여 음경해면체의 세고고사지수 (TUNEL 염색)와 해면체 평활근 분포비율 (alpha-smooth muscle actin)을 조사하고, 해면체 평활근 이완에 관여하는 nitric oxide synthase (NOS) 경로와 평활근 수축에 관여하는 RhoA/Rho-kinase 경로에서 핵심적인 역학을 담당하는 물질들 (nNOS, eNOS, Akt, MYPT1, PTEN)의 단백 발현 변화를 조사하였다. 음경해면체 평활근의 구조적, 기능적 변화 양상은 발기반응의 생리학적 지표와 연관되어 비교되었으며, 최종적으로는 혈당 조절 정도에 따라 분석되었다. 결과: 당뇨를 유발한 백서에서 유발 후 10주까지 평균 혈당에는 별다른 차이가 없었다. 10주 이후 당뇨병이 유발된 백서를 2, 3, 4군으로 무작위 배정한 후 실험군별로 인슐린 치료를 시작한 2군과 3군에서 평균 혈당은 유의하게 낮게 유지되었다. 평균 당화혈색소 수치는 1, 2, 3, 4군 각각에서 4.1 ± 0.1%, 4.8 ± 0.5%, 7.4 ± 0.5%, 9.2 ± 1.0%로 두 군별로 각각 서로 유의한 차이를 보였다. 백서의 무게는 10주째까지 1군이 다른 군에 비해 유의하게 증가하는 소견을 보였으며 10주째 인슐린 치료를 시작한 이후 2군이 3군에 비해 유의한 체중 증가를 보였다. 4군에서 10주째 이후 체중이 감소하는 소견을 보였다. 평균 남성호르몬 수치는 1, 2, 3, 4군 각각에서 1.7 ± 0.3, 0.9 ± 0.2, 1.6 ± 0.6, 1.1 ± 0.2 (nmol/L)였으며 두 군별로 각각 비교하였을 때 2, 3, 4군은 서로 유의한 차이를 보이지 않았으며 (P=0.879) 이에 비해 1군은 유의하게 높은 수치를 보였다 (P=0.041). 해면체신경 자극시 주파수에 따라 발기력이 상승하는 소견을 보였으며 해면체신경 자극전 기저 해면체내압은 별다른 차이를 보이지 않았다 (P=0.774). 1군에서 해면체내압 및 해면체내압곡선의 AUC가 가장 높았다. 2군에서 해면체 내압은 1군과 유의한 차이를 보이지 않았으며 20Hz 자극에서만 해면체내압곡선의 AUC가 1군에 비해 유의하게 저하된 소견을 보였다. 3군에서는 해면체내압과 해면체내압곡선의 AUC 모두 유의하게 감소하였으며 4군은 3군에 비해 더 낮은 해면체내압과 해면체내압곡선의 AUC값이 모두 감소하였으나 통계적으로 유의한 차이를 보이지 않았다. 세포고사지수는 혈당조절수준이 악화됨에 따라 증가하는 소견을 보였다. 1, 2, 3, 4군의 세포고사지수는 각각 8.3 ± 1.7%, 10.5 ± 2.0%, 15.7 ± 3.7%, 19.5 ± 4.0%였으며 1군과 2군은 유의한 차이를 보이지 않았다. 세포고사지수는 2군에 비해 3군에서 유의하게 증가하였고 3군에 비해 4군에서 유의한 증가를 보였다. 이와 반대로 해면체 평활근 분포비율은 1군과 2군에서 차이를 보이지 않았으며 2군에 비해 3군이 유의하게 감소하고, 3군에 비해 4군에서 유의한 감소를 보였다. 분자생물학적 결과를 살펴보면 nNOS 발현이 2, 3, 4군에서 별다른 차이를 보이지 않았으나 1군에 비해 모두 유의하게 감소한 소견을 보였다. RhoA/Rho kinase 경로의 활성화와 관련한 MYPT 전체 단백에 대한 인산화된 단백의 비율이 3, 4군에서 유의하게 증가하였으며 eNOS 경로와 관련된 eNOS와 Akt 단백이 1, 2군에 비해 3, 4군에서 유의하게 감소된 소견을 보였다. 결론: 본 연구를 통해 혈당 조절 정도에 따라 발기력이 차이를 보인다는 점을 분명히 하였으며, 발기력을 최대한 보존하기 위하여 엄격한 혈당 조절이 필요함을 확인하였다. 이는 nNOS 발현 및 남성호르몬 수치의 차이, 세포고사의 증가 및 해면체 평활근 분포비율의 감소, RhoA/Rho kinase 경로의 활성화와 eNOS 경로의 억제 기전이 관여하였다.Objectives: Poor glycemic control is associated with erectile dysfunction (ED); however, differences in ED according to the level of glycemic control have been poorly investigated. The aim of the present study is to investigate the change in erectile function according to the level of glycemic control and to clarify the pathophysiologic mechanism of diabetes-associated ED. Materials and methods: Streptozotocin was injected into fifty-five male Sprague-Dawley rats classified into four groups: control (group 1), diabetes with multiple insulin injections (group 2), diabetes with a single injection (group 3) and untreated diabetes (group 4). Daily insulin injections in groups 2 and 3 for 4 wk after 10 wk of diabetic induction. ANOVA or Kruskal-Wallis test to evaluate glycosylated hemoglobin (HbA1c), testosterone levels, the ratios of intracavernosal pressure over mean arterial pressure (ICP/MAP), area under the ICP curve over MAP (AUC/MAP), changes in cavernous tissue and protein expression related to Rho kinase and nitric oxide pathways. Results: HbA1c levels were different between pairs of groups. Group 4 showed the lowest erectile parameters and group 2 showed near normal level. No differences in erectile parameters were found between groups 1 and 2 or groups 3 and 4, except AUC/MAP for group 1 was significantly higher than that of group 2 (20 Hz stimulation). Decrease in erectile function of group 2 was related to decreased expression of nNOS or decreased testosterone level compared to group 1. Groups 2 and 3 showed significant differences in erectile parameters, which were associated with difference in apoptotic index. Groups 3 and 4 showed no differences in erectile parameters, although these groups had significant differences in apoptotic index, smooth muscle component and protein expression ratios of phosphorylated/total MYPT1, eNOS and Akt. Conclusions: Improvement in glycemic control assists recovery from diabetes-associated ED; however, only tight glycemic control can provide recovery from ED to a near normal status.Docto

구리 표면 위에서의 그래핀 합성에 대한 핵 생성 및 성장 연구

학위논문 (박사)-- 서울대학교 대학원 : 재료공학부, 2015. 2. 김기범.In this dissertation, two major issues of graphene growth and solutions for two issues were discussed. First issue is developing transfer-free graphene growth process on target substrate (chapter 3 and 4) and the other issue is study on graphene growth and obtaining high-quality and large grain size graphene via understanding nucleation and growth kinetics (chapter 5 and 6). In introductory part (chapter 1 and 2), general overview on graphene and growth methods is presented. Literature survey on previous graphene growth work and motivation for following work in this dissertation are also covered in chapter 1. In the chapter 2, review on various approaches for obtaining high-quality graphene will be covered based on its fundamental aspects of nucleation and growth. The relationships between each parameters of growing graphene and properties of as-grown graphene are discussed. In chapter 3, a rapid graphene growth method that can be carried out on any desired substrate, including insulator, thus negating the need for the transfer from metal substrate is introduced. Rapid annealing of a bilayer of a-C and metal deposited on the surface leads to the formation of graphene film, and to subsequent breaking-up of the thin metal layer underneath the film, resulting in a formation of a graphene-metal hybrid film which is both transparent and electrically conducting. In chapter 4, graphene film on silicon substrates having various orientations by simple heating in the presence of carbon source gas is discussed. We observed that a 3C-SiC (111) film would form upon carburizing silicon with carbon deposited from a carbon source because it is well lattice-matched with Si (110) (less than 2 %). Graphene grew on the buffer layer of 3C-SiC (111). The surface consists of hexagonal arrays that can act as a template for graphene growth. In chapter 5, the effect of gas transport inside a micrometre-scale jig gap on the growth of graphene on Cu foil located in the gap is reported. Due to the small size of the gap, a boundary layer is fully developed inside the gap, and the gas molecule transport is controlled by the molecular flow. First, the Cu surface is protected from the sublimation and re-deposition of Cu during pre-annealing, which results from the relatively static gas environment of the molecular gas flow. Second, suppression of the gas conductance resulted in strongly reduced overall graphene coverage with a smaller average grain size but with almost the same density as that of the graphene nuclei. Furthermore, the suppression of gas conductance leads to the formation of well-bounded graphene morphology instead of a dendritic morphology. In chapter 6, continuous graphene layer was grown on top of liquid Cu surface and grain boundaries were revealed by SEM (Scanning electron microscopy) and optical characterization via Cu oxidation. Hydrogen etch revealed the grain boundaries of graphene on liquid Cu easily. Small gaps exist between graphene islands even after few hours of growth time, thus, CH4 flux was increased at the final step of chemical vapor deposition growth in order to confirm the stitching of graphene islands. Hydrogen etch and optical characterization clearly demonstrated that graphene islands are uniform before and even after the merging of its graphene grains and tiny gaps between graphene islands were fully stitched by two-step growth method. Transmission electron microscopy images and diffraction pattern study revealed the importance of self-assembly. The resistance was measured by TLM (Transfer length measurement) pattern. Grain boundary resistance was considered to be negligible if two grains meet in the same direction without rotation of atomic lattice on liquid Cu, which has a great impact compared to typical grain boundary. In conclusion, novel graphene growth methods for direct formation on target substrate were suggested. Also, based on the fundamental understanding of nucleation and growth of graphene synthesis, two approaches are studied which are enlarging grain size and self-assembly. Graphene growth on catalytic metal surfaces is governed by heteronuclei effect, and overcoming way is self-assembly via growth on liquid catalyst according to this study.CHAPTER 1. Introduction 1.1. Graphene as a two-dimensional material 1.1.1. General overview of graphene 1.1.2. Physical properties of graphene 1.2. Alternative graphene growth methods 1.2.1. Reduction of graphene oxides 1.2.2. Epitaxial growth (sublimation of SiC) 1.2.3. Chemical vapor deposition 1.3. Understanding on graphene growth on Cu 1.3.1. Graphene synthesis on Cu vs. Ni 1.3.2. Unique aspects of graphene growth on Cu 1.3.3. Motivation for work: Transfer issue and polycrystalline nature References CHAPTER 2. Review on graphene growth on Cu 2.1. Introduction 2.2. Observation of growth kinetics 2.3. Surface treatment of Cu foil 2.4. Effect of growth temperature 2.5. Source gas feeding rate 2.6. Morphology evolution and hydrogen etching 2.7. Approaches for large single crystal graphene 2.7.1. Gas transport control 2.7.2. Seeded growth 2.7.3. Graphene growth on liquid Cu References CHAPTER 3. Direct graphene growth on target substrate: Metal-induced crystallization of a-C 3.1. Introduction 3.2. Experimental details 3.2.1. Deposition and sample preparation 3.2.2. Analysis of the film 3.3. Results and discussion 3.4. Summary and conclusions References CHAPTER 4. Direct graphene growth: Graphene formation by direct carbon source feeding on Si substrate 4.1. Introduction 4.2. Experimental details 4.3. Results and discussion 4.4. Summary and conclusions References CHAPTER 5. Gas transport control in graphene growth: Micro-meter scale gap jig effect 5.1. Introduction 5.2. Experimental details 5.3. Results and discussion 5.3.1. Jig effect on pre-annealing 5.3.2. Gas transport effect on graphene growth 5.3.3. Morphology evolution of graphene grains 5.4. Summary and conclusions References CHAPTER 6. Mesoepitaxy: Graphene growth on liquid Cu 6.1. Introduction 6.2. Experimental details 6.2.1. Graphene growth on liquid Cu and two-step growth 6.2.2. Transfer and VDP pattern fabrication 6.2.3. Liftoff and TLM patterning 6.3. Results and discussion 6.3.1. Structural study of graphene grown on liquid Cu 6.3.2. Revealing grain boundaries of graphene on liquid Cu 6.3.3. Two-step growth for continuous graphene 6.3.4. Electrical transport study 6.4. Summary and conclusions References CHAPTER 7. Summary, ConclusionsDocto

Image Haze Removal Using Single Pixel Approach Based on Dark Channel Prior with Fast Filtering

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Fast Moving Object Detection for a Dynamic Scene Using Optical Flow

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