• 센서학회지
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• 제9권4호
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• pp.297-306
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• 2000

최근 MEMS 소자의 성능향상을 위하여 수십 ${\mu}m$의 두께를 가지는 고형상비 단결정실리콘 구조물 제작에 관한 연구가 활발하게 진행되고 있다. 그러나 이러한 고형상비 단결정실리콘 구조물 제작 기술에서는 구조물의 구동 또는 전기신호의 검지를 위한 전극 사이의 전기적인 절연 방법이 주된 문제로서 대두되고 있다. 본 논문에서는 고형상비를 가지는 단결정실리콘 구조물 전극 간의 전기적 절연을 위하여 고형상비 산화막으로 구성된 빔 및 측벽을 이용한 새로운 절연 기술을 개발하였다. 개발된 절연 기술은 실리콘 구조물을 측면 또는 하부에서 산화막으로 지지하는 절연 구조를 가진다. 이러한 트렌치 산화막은 그 깊이가 수십 ${\mu}m$이므로 산화막의 잔류응력이 구조물에 미치는 영향을 반드시 고려하여야 한다. 본 논문에서는 PECVD 방법으로 증착한 TEOS 산화막으로 절연 구조들을 제작하였으며, 제작된 절연구조들의 잔류응력을 측정하고, 그 잔류응력이 구조물에 미치는 영향을 해석하였다. 또한 공진자를 이용하여 개발된 절연 기술이 고형상비 단결정실리콘 구조물에 효과적으로 쓰일 수 있음을 보였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.727-728
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.563-564
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.623-624
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• 2010

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.473-476
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• 2002

Micro turbine that is a component of micro power system refers to turbines on the scale of centimeters which can transmit power on the order of tens of Watts. Such devices can be used as propulsion or power generation devices for various potable and micro devices. An interdisciplinary team at Seoul National University has designed, fabricated and tested such a device, and this paper describes test results.

• 한국군사과학기술학회지
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• 제5권3호
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• pp.120-124
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• 2002

Microturbine refers to turbines on the scale of centimeters which can transmit power on the order of tens of Watts. Such devices can be used as propulsion or power generation devices for various military systems. An interdisciplinary team at Seoul National University has designed, and fabricated such a device, and this paper describes each phase. A commercial code has been used for design, and MEMS processes have been used for manufacturing. Finally, some preliminary test results are presented.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.381-386
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• 2001

This paper reports on the development of micro power system under way at Seoul National University. The interdisciplinary tin consists of members with various backgrounds of mechanics and materials. The need for micro power systems is explained, and a turbine under development is described. Design, and fabrication are introduced, and technical challenges in each phase are described. Furthermore, the interaction between the available fabrication methods and design is explained. Design involves use of commercially available codes to analyze flow fields, and fabrication takes advantage of the silicon wafer etching processes used to manufacture semiconductor devices.

• Design & Manufacturing
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• 제2권2호
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• pp.6-9
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• 2008

Injection molding is representative process of plastic production. Most of numerical analyses for injection molding have been based on the Hele Shaw's approximation: two-dimensional flow analysis. The present work covers numerical analyses of injection molding using three-dimensional solid elements. The accuracy of the analysis results has been verified through some numerical examples in comparison with the various conditions. In this study, moldflow software was used to analyze the cooling analysis. The results of cooling analysis and testing catapult were compared for plastic products.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.44-47
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• 2009

In this paper, limitation of rigid-plastic finite element method caused from rigid-plasticity assumption and numerical problem is investigated in detail and a useful scheme is proposed to get rid of the plastic deformation in rigid or elastic region. A typical example of a possible long bar extrusion process is given, which may be impossible to simulate without using the proposed scheme. The scheme is successfully applied to simulating the long bolt forging processes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1563-1565
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• 2008

Hydrophobic plastic plates employing nano surface features are injection molded using thermoplastic materials. A variotherm molding process is devised for filling the nano pores and releasing the molded nano features from the master. The size of the molded nano surface features are about 100nm in diameter and 200nm in height. The size of the molded plate is about 30mm x 30mm and the thickness is 1mm. As molding materials, Polypropylene, PMMA, COC and PC are employed, which are all typical commodity thermoplastic materials. The mold temperature(stamper temperature) is investigated as a major processing parameter for molding high aspect ratio nano surface features. Almost fully molded nano features are fabricated above a certain level of mold temperature depends on the employing material. The contact angles on the injection molded plates are measured to estimate the hydrophobicity and found to have higher contact angle up to 180% compared to the blank plate with no surface features.