• Proceedings of the KWS Conference
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• 2003.05a
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• pp.193-195
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• 2003

Micro-structure and shear properties with reflow conditions, reflow temperature and time, for In-48Sn solder on BGA package were examined at the temperature between 140 and 170$^{\circ}C$ for 10 to 3600sec. With increasing reflow temperature and time, the thickness of intermetallic compound formed between solder and pad increased. Shear test indicated shear force increased in the range to a critical value of reflow time, and decreased over a critical reflow time. With increasing reflow temperature and time, the crater occurred on fracture surface because of a increase of crater by voids and IMC particles precipitated in solder.

• International Journal of Air-Conditioning and Refrigeration
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• v.12 no.3
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• pp.141-147
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• 2004

Cogeneration has been widely introduced in many countries for use m industrial, commercial and residential applications. However, there have been few models with an output of less than 100kW. In the present study, a spark ignited gas engine with electric generation output of 10kW was developed for micro cogeneration package. Developed gas engine achieved following performance characteristics such as $26.7\%$ of electric generation efficiency, NOx emission less than 10 ppm at $13\%$ oxygen, 82 dB of noise level, and about 3 seconds of switching time from idling to nominal power.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.697-703
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• 2003

Cogeneration is the simultaneous generation of heat and electricity in a single unit, and is a highly energy-efficient technology compared to the independent generation of both products. Therefore, cogeneration has been widely introduced in many countries for use in industrial, commercial and residential applications. However, there have been few models with an output of less than 100 kilowatt. In the present study, a spark ignited gas engine with electric generation output of 10 kilowatts was developed for micro cogeneration package. The gas engine shows 26.7% of electric generation efficiency, NOx emission less than 10 ppm at 13% oxygen, 82 dB of Noise level, and about 3 seconds of switching time from idling to nominal power.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1051-1054
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• 2000

We developed the micro CSF (celebrospinal fluid) shunt valve with surface and bulk micromachining technology in polymer MEMS. This micro CSF shunt valve was formed with four micro check valves to have a membrane connected to the anchor with the four bridges. The up-down movement of the membrane made the CSF on & off and the valve characteristic such as open pressure was controlled by the thickness and shape of the bridge and the membrane. The membrane, anchor and bridge layer were made of the $O_2$ RIE (reactive ion etching) patterned Parylene thin film to be about 5~10 microns in thickness on the silicon wafer. The dimension of the rectangular nozzle is 0.2＊0.2 $\textrm{mm}^2$ and the membrane 0.45 mm in diameter. The bridge width is designed variously from 0.04 mm to 0.12 mm to control the valve characteristics. To protect the membrane and bridge in the CSF flow, we developed the packaging system for the CSF micro shunt valve with the deep RIE of the silicon wafer. Using this package, we can control the gap size between the membrane and the nozzle, and protect the bridge not to be broken in the flow. The total dimension of the assembled system is 2.5＊2.5 $\textrm{mm}^2$ in square, 0.8 mm in height. We could precisely control the burst pressure and low rate of the valve varing the design parameters, and develop the whole CSF shunt system using this polymer MEMS fabricated CSF shunt valve.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1142-1144
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• 1999

A 4-beam cross type silicon elastic body was fabricated for the electromagnetic type vibration micro transducer. To improve energy transfer efficiency, the structure and size of vibration transducer were optimized by the FEA simulation package. Experimental results of the fabricated transducer shows $0.5{\sim}8$ dyne of vibration force at the condition of $1{\sim}4$ mA of current source $100{\sim}7000$ Hz of frequency band width. These results presented the useful applications for micro actuators and sensors.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.845-851
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• 1986

This Paper presents micro-computer simulation programs for a pneumatic control system. The simulation programs have been written in BASIC language which is suitable for 6502CPU with 48KB memory and consist of 11 programs which describe the time response and frequency response of the pneumatic actuation system. This simulation package is stored in 51/4 inch floppy diskette. The user requires no simulation expertise on the part of designer. As the result of using this simulation programs for the pneumatic control system with stabilizing tank, it has shown that the response time of the system using air as working medium takes more time to be settled but relatively stable rather than the system using helium.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2372-2373
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• 2005

The design of a piezoelectric actuator for micro droplet ejecting system has bee studied. The actuator has been evaluated by using commercial FEM package and its displacement are measured by LDV(Laser Doppler Vibrometer). The characteristics of the actuator are evaluated with varation in a ratio of width of PZT to that of membrane and thickness ratio of PZT to membrane.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.1046-1050
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• 2005

Micro Cellular Plastics create a sensation at polymer industrial for lowering product cost & overcoming a lowering of mechanical intensity. There Is much development from injection molding pans but Extrusion parts is slow. This research is MCPs Extrusion parts, It is basis experiment for Process to make beads that is basis raw material of Package used most by shock mitigative of industry.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.76-81
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• 1998

The purpose of this study is the generation of B-spline surface by the 3D measurement data. The hardware of the system comprises PC and digitizing machine, machining center. There are three steps, (1) physical model measuring on the 3D laser digitizing machine, (2) B-spline surface modeling and Fairing, (3) CNC machining by the NC code. It is developed a software package, with which can conduct a micro CAM system in the PC without economical burden.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1990.04a
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• pp.11-21
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• 1990

본 논문에서는 시계열 자료 분석을 위한 마이크로 컴퓨터용 통계패키지인 TIMESLAB을 소개하였다. TIMESALB은 종래의 통계 분석용 패키지인 SPSS, SAS, TSP 들이 대형 컴퓨터 시스템에 맞도록 설계되어 있어 PC에 서 활용하기에는 많은 디스크 용량을 필요로 하는 등의 문제점을 모두 극복 한 PC용 시계열 자료 분석 프로그램이다. TIMESLAB은 대화용으로 설계되 어 있고 아주 적은 하드 디스크 용량만 가지고서도 쉽게 접근이 가능한 편 리한 시스템의 그 구성, 활용 및 명령어들을 제시하였고, 예제 프로그램과 그 결과를 제시하였다.