• 한국산학기술학회논문지
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• 제14권2호
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• pp.511-516
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• 2013

유리 모서리 접합은 디스플레이 및 건축, 가전 등 산업계의 다양한 분야에 활용되고 있으며, 패널 접합부의 두께 및 형상은 단열성능 및 강도 등 패널의 주요 성능에 큰 영향을 미치는 요인으로 작용한다. 이런 모서리 접합부의 단면은 수소혼합가스토치를 이용하여 모서리를 용융 접합 할 경우 공정변수에 의해 형상이 결정된다. 따라서 본 논문에서는 가스토치를 이용하여 모서리 접합 시 접합부에 영향을 미치는 공정변수를 설정하고, 접합단면의 형상변수를 설정하여 두 변수간의 상관관계를 분석하기 위한 회귀식을 도출하고자 하였다. 회귀식 도출을 위해 공정변수가 형상변수에 미치는 주효과 및 교호작용을 분석하였으며, 변수간의 교호작용을 고려한 다항회귀식을 도출하였다. 도출된 다항회귀식을 통해 각 공정변수 변화에 따라 모서리 접합 두께 예측 및 처짐량 예측이 가능하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.843-846
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• 1992

This thesis was investigated on optical-and ion-induced characteristics in positive(a-$Se_{75}Ge_{25}$) and negative (Ag/a-$Se_{75}Ge_{25}$) resists for focused-ion-beam microlithogaphy. The a-$Se_{75}Ge_{25}$ inorganic thin film shows an increase in optical absorption after exposure to$\sim$$10^{16}$ dose(ions/$cm^{2}$) of Ga ions. The observed shift in the absorption edge toward longer wavelengths is consistent with that in films exposed to band-gap photons ($\sim$$10^{20}$ photons/$cm^{2}$). But, ion induced shift is twice as much as that in film exposed to optical radiation. This result may be related with microstructural rearrangements with in the short range of SeGe network. Due to changes in the short range order, the chemical bonding may be affected, which results in increased chemical dissolution in ion-induced film. Also, this resist exhibits good thermal stability because of its high Tg(~220$^{\circ}C$). The composition of deposited film measured by AES is consistent with that of bulk.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.221-221
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• 2013

Striving to replace the well known silicon nanocrystals embedded in oxides with solution-processable charge-trapping materials has been debated because of large scale and cost effective demands. Herein, a silicon quantum dot-polystyrene nanocomposite (SiQD-PS NC) was synthesized by postfunctionalization of hydrogen-terminated silicon quantum dots (H-SiQDs) with styrene using a thermally induced surface-initiated polymerization approach. The NC contains two miscible components: PS and SiQD@PS, which respectively are polystyrene and polystyrene chains-capped SiQDs. Spin-coated films of the nanocomposite on various substrate were thermally annealed at different temperatures and subsequently used to construct metal-insulator-semiconductor (MIS) devices and thin film field effect transistors (TFTs) having a structure p-$S^{++}$/$SiO_2$/NC/pentacene/Au source-drain. C-V curves obtained from the MIS devices exhibit a well-defined counterclockwise hysteresis with negative fat band shifts, which was stable over a wide range of curing temperature ($50{\sim}250^{\circ}C$. The positive charge trapping capability of the NC originates from the spherical potential well structure of the SiQD@PS component while the strong chemical bonding between SiQDs and polystyrene chains accounts for the thermal stability of the charge trapping property. The transfer curve of the transistor was controllably shifted to the negative direction by chaining applied gate voltage. Thereby, this newly synthesized and solution processable SiQD-PS nanocomposite is applicable as charge trapping materials for TFT based memory devices.

• 에너지공학
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• 제7권2호
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• pp.163-171
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• 1998

고분자 첨가물의 퇴화는 시험용액의 고온상태에서 증가된다. 합성고분자용액의 퇴화에 대해 시간에 따른 온도와 고분자 농도의 영향을 알아보기 위해 6$0^{\circ}C$, 8$0^{\circ}C$의 온도와 100, 200, 400, 600 ppm의 다양한 고분자 농도에 따라 폐회로방식으로 실험적인 연구를 하였다. 퇴화효과는 기계적 퇴화보다 온도에 더 의존적임이 밝혀졌다. 마찰계수와 레이놀즈 수의 관계는 레이놀즈 수가 5만부터 15만까지의 범위에서 레이놀즈 수가 증가함에 따라 마찰계수가 감소하고, 저온에서 마찰은 Vi가의 최대마찰저항감소 점근선에 접근한다는 것을 보인다. 일정한 유량과 온도에 대해, 높은 고분자 농도에서 퇴화효과가 더 작게 밝혀졌다. 일정한 유량과 고분자 농도에 대해서는 퇴화율이 주로 온도에 영향받는 것으로 밝혀졌다. 8$0^{\circ}C$의 온도, 100 ppm의 고분자 농도에서 4시간후에 마찰저항 감소효과가 없어졌다. 그러나, 열적퇴화는 고분자 분자들간의 결합력을 증가시켜 주는 것으로 생각되는 계면활성제 같은 추가적인 물질을 이용하여 극복할 수 있을 것이다.

• Current Photovoltaic Research
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• 제2권4호
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• pp.168-172
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• 2014

Under concentrated illuminations, the solar cells show higher efficiencies mainly due to an increase of the open circuit voltage. In this study, InGaP/InGaAs/Ge triple-junction solar cells have been grown by a low pressure metalorganic chemical vapor deposition. Photovoltaic characteristics of the fabricated solar cells are investigated with a class A solar simulator under concentrated illuminations from 1 to 100 suns. Ideally, the open circuit voltage should increase with the current level when maintained at the same temperature. However, the fabricated solar cells show degraded open circuit voltages under high concentrations around 100 suns. This means that the heat sink design is not optimized to keep the cell temperature at $25^{\circ}C$. To demonstrate the thermal degradation, changes of the device performance are investigated with different bonding conditions and heat sink materials.

• 폴리머
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• 제25권6호
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• pp.774-781
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• 2001

폐타이어와 폐석분 재활용을 위하여, 불포화 폴리에스터 수지에 폐석분과 폐타이어 분말의 충전량을 변화시켜 폐타이어-폐석분/폴리에스터 혼성 복합재료를 제조하였다. 매트릭스 내에서 충전제의 계면결합력과 분산력을 향상시키기 위하여 실란 커플링제[${\gamma}$-methacryloxy propyl trimethoxy silane(${\gamma}$-MPS)]를 사용하여 표면처리하고 복합재를 제조한 후 구조와 물성을 확인하였다. 실란 커플링제로 충전제를 표면처리한 경우 초기 열분해온도가 상승하고 중량감소율이 감소하였다. 커플링제로 표면처리된 경우 높은 기계적 물성을 얻었으며, 실란 농도 2 wt%에서 매트릭스 및 WTC의 함량에 관계없이 최대값을 나타내었다. 유기 충전제 증가에 따라 복합재의 기공도는 증가하나 표면처리에 의해 감소시킬 수 있으며 유기 충전제의 함량에 따라 기공 크기분포도 변화한다.

• 소성∙가공
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• 제15권9호
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• pp.667-672
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• 2006

Agglutination is one of the most commonly employed reactions in clinical diagnosis. In this paper, we have designed and fabricated nickel mold insert for injection molding of a microfluidic lab-on-a-chip for the purpose of the efficient detection of agglutination. In the presented microfluidic lab-on-a-chip, two inlets for sample blood and reagent, flow guiding microchannels, improved serpentine laminating micromixer(ISLM) and reaction microwells are fully integrated. The ISLM, recently developed by our group, can highly improve mixing of the sample blood and reagent in the microchannel, thereby enhancing reaction of agglutinogens and agglutinins. The reaction microwell was designed to contain large volume of about $25{\mu}l$ of the mixture of sample blood and reagent. The result of agglutination in the reaction microwell could be determined by means of the level of the light transmission. To achieve the cost-effectiveness, the microfluidic lab-on-a-chip was realized by the injection molding of COC(cyclic olefin copolymer) and thermal bonding of two injection molded COC substrates. To define microfeatures in the microfluidic lab-on-a-chip precisely, the nickel mold inserts of lab-on-a-chip for the injection molding were fabricated by combining the UV photolithography with a negative photoresist SU-8 and the nickel electroplating process. The microfluidic lab-on-a-chip developed in this study could be applied to various clinical diagnosis based on agglutination.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.139-144
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• 2005

A rigorous research is underway in our team, for the design and development of high figure of merits (ZT= 1.5${\sim}$2.0) micro-thermoelectric coolers. This paper discusses the fabrication process that we are using for developing the $Sb_2Te_3-Bi_2Te_3$ micro-thermoelectric cooling modules. It describes how to obtain the mechanical properties of the thin film TEC elements and reports the results of an equation-based multiphysics modeling of the micro-TEC modules. In this study the thermoelectric thin films were deposited on Si substrates using co-sputtering method. The physical mechanical properties of the prepared films were measured by nanoindentation testing method while the thermal and electrical properties required for modeling were obtained from existing literature. A finite element model was developed using an equation-based multiphysics modeling by the commercial finite element code FEMLAB. The model was solved for different operating conditions. The temperature and the stress distributions in the P and N elements of the TEC as well as in the metal connector were obtained. The temperature distributions of the system obtained from simulation results showed good agreement with the analytical results existing in literature. In addition, it was found that the maximum stress in the system occurs at the bonding part of the TEC i.e. between the metal connectors and TE elements of the module.

• Korean Chemical Engineering Research
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• 제53권1호
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• pp.53-56
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• 2015

초임계 암모니아 분위기와 CuI 촉매 하에서 p-Diiodobenzene(PDIB)를 아민화 반응시켜 p-Phenylenediamine(PPD)를 합성하는 방법을 연구하였다. 본 연구에서는 여러 가지 공정변수들이 PPD 생성 수율에 미치는 영향을 알아보기 위하여 반응 온도, 암모니아 초기 주입 양에 따른 반응 압력, 촉매의 유무 및 촉매 주입량, 반응 시간 등을 변화시키면서 이에 따른 PPD 수율 변화를 GC 분석을 통하여 조사하였다. 그 결과, 무촉매 반응 시에는 PPD가 전혀 생성되지 않음을 알 수 있었으며, 반응온도, 반응 압력, 촉매 주입량 및 반응시간이 증가함에 따라 PPD 생성 수율이 증가하는 것을 확인할 수 있었다 단, 반응온도의 경우 $250^{\circ}C$ 이상에서는 열분해에 의해 PPD가 감소하여 $200^{\circ}C$가 최적의 온도임을 알 수 있었다. 또한, FT-IR과 $^1H$-NMR 분석을 통하여 아민기의 결합 특성과 PPD의 구조를 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.529-529
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• 2006

Several laboratories worldwide have demonstrated the feasibility of producing amorphous silicon thin film transistor (TFT) arrays at temperatures that are sufficiently low to be compatible with flexible foils such as stainless steel or high temperature polyester. These arrays can be used to fabricate flexible high information content display prototypes using a variety of different display technologies. However, several questions must be addressed before this technology can be used for the economic commercial production of displays. These include process optimization and scale-up to address intrinsic electrical instabilities exhibited by these kinds of transistor device, and the development of appropriate techniques for the handling of flexible substrate materials with large coefficients of thermal expansion. The Flexible Display Center at Arizona State University was established in 2004 as a collaboration among industry, a number of Universities, and US Government research laboratories to focus on these issues. The goal of the FDC is to investigate the manufacturing of flexible TFT technology in order to accelerate the commercialization of flexible displays. This presentation will give a brief outline of the FDC's organization and capabilities, and review the status of efforts to fabricate amorphous silicon TFT arrays on flexible foils using a low temperature process. Together with industrial partners, these arrays are being integrated with cholesteric liquid crystal panels, electrophoretic inks, or organic electroluminescent devices to make flexible display prototypes. In addition to an overview of device stability issues, the presentation will include a discussion of challenges peculiar to the use of flexible substrates. A technique has been developed for temporarily bonding flexible substrates to rigid carrier plates so that they may be processed using conventional flat panel display manufacturing equipment. In addition, custom photolithographic equipment has been developed which permits the dynamic compensation of substrate distortions which accumulate at various process steps.