Three dimensional finite element analysis on the minimum contact fraction of bone-implant interface

학위논문(박사)--서울대학교 대학원 :치의학과 치과보철학전공,1997.Docto

Nilpotent 리 군 위의 평 아핀 구조

Thesis (doctoral)--서울대학교 대학원 :수학과,1998.Docto

한국 4세대 저장링에서의 빔동역학 연구

Doctor본문에서 저장링 내에서의 선형 동역학과 비선형 동역학에 대한 설명을 포함하여 Korea-4GSR의 격자 구조는 기술된다. 에미턴스를 줄이기 위해서 MBA 격자 개념이 적용되고, longitudinal gradient bending magnet과 reverse bending magnet이 이용된다. 비선형 효과는 육극자석을 최적화하여 통제한다. 최적화 결과는 resonance driving term이 잘 상쇄되는 것을 보여준다. Korea-4GSR에서의 IBS 효과도 조사하였다. IBS에 의한 에미턴스 증가는 평평한 빔일 때 14 %, 둥근 빔일 때 5%이다. IBS와 연관된 Touschek lifetime은 빔 lifetime에 가장 결정적인 영향을 미치고 lifetime은 평평한 빔일 때 4.54 시간, 둥근 빔일 때 8.81 시간이다. 디자인이 현실적인지 확인하기 위해서 에러 보정 전산모사 그리고 입사 전산모사를 수행했다. 전산모사에서 에러들은 잘 보정되었고 입사 효율은 약간의 입사빔 에너지 편차가 있을 때 100 %였다. 종합해보면 Korea-4GSR 격자 디자인은 작은 자연에미턴스를 만든다. 이때, IBS 효과에 의한 에미턴스 증가는 작고 lifetime 또한 빔 운전하기에 충분히 길다. 그리고 그 디자인의 현실성은 전산모사를 통해 확인하였다.In this dissertation, we present a newly designed magnetic lattice of the Korea fourth-generation storage ring (Korea-4GSR) and results of linear and non-linear beam dynamics studies. This storage ring employs the multi-bend achromat (MBA) structure to achieve very small natural emittance of an electron beam. The designed natural emittance is 58 pm, the electron-beam energy is 4 GeV, and the ring circumference is approximately 800 m. To realize a very small emittance, longitudinal gradient bending magnets together with reverse bending magnets are introduced, both of which led the emittance reduction down to two orders of magnitude smaller than that in existing third-generation storage rings. Damping wiggler option is also studied to explore the possibility of further reduction of the emittance, and it is found that the natural emittance can be reduced to 34 pm. Harmful non-linear effects are controlled by optimizing the distribution and strength of sextupoles. Then resonance driving terms are obtained and analyzed to examine their impact on nonlinear dynamics. This study is validated by considering on- and off-momentum dynamic apertures. It is found that the resulting dynamic apertures are large compared to those in other 4GSRs. Effect of the Intrabeam scattering (IBS) on the beam emittance is investigated and it is confirmed that the chosen electronbeam energy and the natural emittance are close to optimal considering the emittance increase due to IBS. Tolerance for various magnetic errors including those that lead to closed-orbit distortion and magnetic multipole errors are investigated, and orbitcorrection scheme is also described. Finally, a method for injection into the storage ring is presented and it is confirmed that due to large dynamic aperture the conventional off-axis injection is feasible for the Korea-4GSR

Plant-wide Optimization of a TPA Process Using Simulator

Maste

Rule-based Spatial Signature Analysis for the Semiconductor Wafer map

Maste

THE EFFECT OF PREPARATION PROCEDURE ON IMPLANT-ABUTMENT JOINT STABILITY

Statement of problem: Little is known about the effect of abutment preparation procedure on do-torque values in different implant platform and the relationship of final do-torque values with different implant platform size. Purpose: This study evaluated the effect of abutment preparation procedure on do-torque values in different implant platform and the relationship of final do-torque values with different implant platform size. Material and method: Six ITI implants (2 narrow-neck implants, 2 regular-neck implants, 2 wide-neck implants) and six Branemark implants (2 narrow platforms, 2 regular platforms, 2 wide platforms) were embedded in each acrylic resin block with epoxy resin. Eighteen abutments (6 narrow-neck implant-abutments, 6 regular-neck implant-abutments, 6 wide-neck implant-abutments) and eighteen esthetic abutments (6 narrow platform-abutments, 6 regular platform-abutments, 6 wide platform-abutments) were tightened to each implant with digital torque gauge. Initial do-torque values were measured using digital torque gauge. After preparation of abutments, Final do-torque values were measured with digital torque gauge. Results and conclusion: 1. Screws loosening or abutments motion were not detected in all experimental group, but some scratches of implant-abutment joints were detected in all group 2. Reduction ratios of final do-torque values were greater than initial do-torque values in all measured group, except in narrow-neck implant-abutment group (p<0.05). 3. Reduction ratios of final do-torque values in wide-neck implant-abutment group were greater than regular-neck implant-abutment group (p<0.01). 4. The greatest standard deviation value was detected in wide platform group in both implant systems

THE EFFECT OF GROWTH FACTORS IN PLATELET-RICH PLASMA ON THE ACTIVITY OF OSTEOBLAST CELL LINE

Statement of problem: Platelet-rich plasma(PRP) is well known to be very effective method to stimulate and accelerate the healing of bone and soft tissue. However, there are few reports which deal with the mechanisms of the PRP on the activation of the osteoblasts. Purpose: This study was aimed to investigate the effect of growth factors in PRP on the activity of osteoblasts. Material and method: To evaluate the effect on human, human osteoblast cell line was cultured. PRP was extracted from the blood of a healthy volunteer. Using the recombinant growth factors of PDGF, , IGF-1, bFGF which are mainly found at bone matrix and their neutralizing antibody, the effect of PRP on the attachment and proliferation of osteoblasts was evaluated. To evaluate the autocrine and paracrine effects, conditioned media(CM) of PRP was made and compared with PRP. By the western blot analysis, the expression of growth factors in PRP, CM was examined. Cell morphology was compared by the light microscope. Results : 1) The effects of CM on osteoblast were similar to the effects of PRP. 2) PRP, CM, recombinant , bFGF, IGF-1 showed significantly higher cellular attachment than control(p<0.05) in the cell attachment assay. In the cell proliferation assay, PRP, CM, recombinant , IGF-1, bFGF, PDGF increased significantly cell proliferation(p<0.01). Among the recombinant growth factors, IGF-1 showed the highest cellular attachment and proliferation. 3) In the western blot assay, bFGF, IGF-1, PDGF weve equally expressed in PRP and CM. 4) The attachment of osteoblast cell decreased significantly after the addition of neutralizing antibody against , IGF-1(p<0.05). In the cell proliferation assay, the addition of neutralizing antibody against , bFGF, PDGF, IGF-1 decreased significantly the cellular proliferation(p<0.05). The amount of decreasing in the cell attachment and proliferation is the highest in at-lGF-1. 5) The cells in control group were flattened and elongated with a few cellular processes in the a light microscope. But, the cells appeared as spherical, plump cells with well developed cellular processes in experimental groups. The cells in PRP and CM had more prominent developed features than recombinant growth factor groups. Conclusions : These findings imply that PRP maximize the cellular activity in early healing period using the synergistic effect, autocrine, paracrine effects of growth factors and increase the rate and degree of bone formation

Informing Korea&apos;s Soft Power Strategy: Evidence from Survey Experiments on Public Perceptions of Public Diplomacy and Foreign Aid

소프트 파워의 정책 및 학문적 중요성은 근래 들어 더욱 많은 관심을 받아왔다. 이를 방증하듯, 2018년 한 해에만도 한국 정부는 소프트파워 주요 정책 수단이라 할 수 있는 공공외교에 240억 원, 공적 원조에 3조 2000억 원의 예산을 투입했다. 그러나 이와 같은 예산 및 관련 노력이 어떠한 방식으로 사용되고 어떤 효과성을 지니는지에 대한 평가는 부족한 것이 현실이다. 본 보고서는 한국의 공공외교 및 공적 원조 노력에 대한 체계적인 평가 및 분석을 목표로 한다. 먼저 본 연구는 공공 외교와 공적 원조 현황 파악을 위해 가용한 기수집된 자료를 모두 통합 분석한 이후 그 결과와 함의에 대해 논의한다. 이어 한국에 대한 외국 국민의 인식을 측정하고자 하는 기존 자료에 대한 메타 분석을 통해 그간 노력의 성취와 보완점을 서술한다. 이에 기반하여 본 연구는 16개국의 3만 2000여 명에 달하는 응답자를 대상으로 자체적인 설문 및 설문 연구 실험을 설계 및 시행한다. 이를 통해 먼저 대상국 국민은 일반적으로 공공 외교나 공적 원조에 있어 국제적인 평판이나 포용적 가치를 중요시함을 보여준다. 또한 각 국가별, 또 국가 내 개별 사회경제적 특성에 따른 각 수단 및 접근의 효과성을 평가하고, 이에 기반한 향후 맞춤형 마이크로 타겟팅 전략의 가능성을 제시한다. 또한 한국 내 배타성의 해소가 대내외적으로 포용적 가치를 증진할 수 있는 가장 효과적 방법의 하나라는 점을 인식하고, 한국 국민의 외국인 및 이주자에 대한 인식을 측정하고 관련된 정책적 접근을 테스트해볼 수 있는 설문 및 설문 실험을 설계 및 시행하였다. 그 결과 한국 국민의 외국인 및 이주자에 대한 정확한 정보 인식은 부족하지만, 인구 특성에 따라 상당한 배타성을 확인할 수 있었으며 이에 대한 구체적, 또 제도적 해결책을 제시한다. 이와 같은 결과에 기반하여 본 연구는 소프트 파워 발전에 있어 가장 효과적인 전략적 접근은 포용성과 다양성의 증진이라는 주장에 실증적 증거를 제시하고, 향후 증거기반정책 수립을 지원하기 위한 체계적인 자료 수집과 엄밀한 분석의 필요성을 제기한다. The importance of soft power has been gaining increasing attention both in the academia and policymaking. In 2018 alone, the Korean government has spent over 24 billion and 3.2 trillion KRW in public diplomacy and foreign aid - arguably the two main policy devices for extending soft power - budget. Yet we do not yet know much about the determinants, let alone the effectiveness of such resources and related effort. This report marks the first comprehensive take on a systematic evaluation of Korea’s public diplomacy and foreign aid efforts. By compiling and reviewing existing data, first, we provide a rigorous quantitative analysis of the distribution patterns and discuss the related implications. Next, we review the existing public opinion surveys and highlight their achievements and shortcomings. We then proceed to design and execute our own multi-country public opinion survey covering over 32,000 respondents in sixteen different countries with a number of survey experimental designs embedded. We find that respondents overall prefer public diplomacy or foreign aid efforts that emphasize international reputation and greater inclusionary attitudes. Yet, we also find a number of interesting within country variations that can help inform devising tailor-made micro-targeting approaches in the future. Finally, recognizing that dealing with exclusionary attitudes at home may provide one of the most effective ways to promote soft power, we also implemented an additional survey as well as experimental modules to measure and tackle exclusionary attitudes against foreign migrants in Korea. We find overall a low level of familiarity with accurate information yet divergent negative sentiments regarding migrants. We further analyze the sub-population within which such tendencies seem to be the strongest, and propose a number of targeted as well as general institutional remedies to tackle such tendencies. Taken together, the findings of this report suggest first and foremost that an effective strategy to enhance soft power will hinge upon how we can promote greater inclusiveness and diversity and highlights the critical role of collecting systematic data and conducting rigorous analysis to support evidence-based policymaking.제1장 서론 제2장 한국 공공외교와 공적개발원조의 현주소 제3장 한국의 국가 이미지 조사에 대한 메타분석(해외한류실태조사와 국가이미지조사를 중심으로) 제4장 대상국의 한국 선호에 대한 주성분 분석 (자체 설문 원자료 생산 및 분석) 제5장 소프트파워 설문 실험 연구 (자체 설문 원자료 생산 및 분석) 제6장 한국 체류 외국인에 대한 인식 제7장 결