우리나라의 통화정책과 경기변동 효과 분석

학위논문(석사) --서울대학교 대학원 :경제학부 경제학전공,2006.Maste

Effect of Temperature on the Micro-scale Adhesion Behavior of Thermoplastic Polymer Film

Adhesion tests were carried out in order to investigate the effect of temperature on the adhesion behavior between a PMMA film and a fused silica lens in the micro scale. For the tests, a microtribometer system was specially designed and constructed. The pull-off forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K and decreased to 300 K. The contact area between the PMMA film and the lens was observed during the test. The adhesion behavior was changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the pull-off force did not change with the increase of temperature. In rubbery state from 383 K to 413 K, the pull-off force increased greatly as the temperature increased. In addition, the area of contact was enlarged. In viscous state above 423 K, the fingering instability was observed in the area of contact when the PMMA film contacted with the lens. It was also found that the adhesion behavior can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off force.21세기 프론티어연구개발 사업인 나노메카트로닉스기술개발사업(08K1401-00611) 및 두뇌한국 21 사

A Study on Tribological Characteristics of Materials for MEMS/NEMS Using Chemically Modified AFM tip

Friction and adhesion tests were conducted to investigate tribological characteristics of materials for MEMS/NEMS using atomic force microscope (AFM). AFM Si tips were chemically modified with a self-assembled monolayer (SAM) derived from trichlorosilane like octadecyltrichlorosilane (OTS) and (1H,1H,2H,2H-perfluorooctyl) trichlorosilane (FOTS), and various materials, such as Si, Al, Au, Cu, Ti and PMMA films, were prepared for the tests. SAMs were coated on Si wafer by dipping method prior to AFM tip to determine a proper dipping time. The proper dipping time was determined from the measurements of contact angle, surface energy and thickness of the SAMs. AFM tips were then coated with SAMs by using the same coating condition. Friction and adhesion forces between the AFM Si tip modified with SAM and MEMS/NEMS materials were measured. These forces were compared to those when AFM tip was uncoated. According to the results, after coating OTS and FOTS, the friction and adhesion forces on all materials used in the tests decreased; however, the effect of SAM on the reduction of friction and adhesion forces could be changed according to counterpart materials. OTS was the most effective to reduce the friction and adhesion forces when counterpart material was Cu film. In case of FOTS, friction and adhesion forces decreased the most effectively on Au films.21세기 프론티어연구개발 사업인 나노메카트로닉스기술개발사업(07K1401-00911) 및 Brain Korea21 프로젝

POLYMER FILM AND METHOD FOR COATING POLYMER FILM

본 발명은 폴리머 필름 및 폴리머 필름의 코팅방법에 관한 것이다. 본 발명에 따른 폴리머 필름의 코팅방법은, 고상의 폴리머 재료에 액상의 용매제가 혼합된 폴리머 용액을 기판 상에 코팅하여 폴리머 필름을 형성하는 제1 단계; 및 상기 기판을 상기 폴리머 재료의 유리전이온도(Tg)보다 높고, 상기 용매제의 끓는점보다 낮은 온도로 소정 시간 동안 가열하는 제2 단계를 포함하고, 상기 제2 단계를 거친 상기 폴리머 재료의 무게비는 상기 폴리머 필름의 전체 무게 대비 0.01 내지 10%이다

A study on adhesion characteristics and measurement of residual layer thickness in UV-nanoimprint lithography

학위논문(박사) - 한국과학기술원 : 기계공학전공, 2012.8, [ viii, 120 p. ]한국과학기술원 : 기계공학전공

WHEELCHAIR

본 발명의 휠체어는, 시트 본체; 상기 시트 본체의 일측과 타측에 배치된 바퀴; 상기 시트 본체의 일측과 타측에 상기 시트 본체와의 연결부분이 삽입되는 시트 프레임; 상기 연결부분의 끝단에서 상기 연결부분이 삽입되는 방향에 수직으로 상기 시트 프레임을 관통하는 프레임 보강대; 및 상기 바퀴의 축에 연결되고, 상기 프레임 보강대가 삽입되는 바퀴 연결 십자축;을 포함하고, 상기 바퀴는 상기 바퀴 연결 십자축과 함께 상기 프레임 보강대를 축으로 하여 회전 가능하다