• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.183-188
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• 2003

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, the effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the Head Disk Interface (HDI) using a particle injection system. It was round that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except fer the particles of specific size and property. As a means to remove the particles of specific sire. the concept of using a stepped taper at the leading edge of the slider is proposed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.401-409
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• 2009

This paper presents a method of calculating the stress intensity factor (K) and crack propagation direction (${\theta}_0$) at the crack-tip that is associated with delamination in the large scale integration(LSI) package. To establish a reasonable strength evaluation method and life prediction, it is necessary to assess fracture parameters under various fracture conditions. Therefore, we conducted quantitative stress singularity analysis considering thermal stress simulating the changes of crack length (a), (h) and (v) in delamination using the 2-dimensional elastic boundary element method (BEM), and from these results predicted crack propagation direction and path.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.131-137
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• 1999

Package crack caused by the soldering process in the surface mounting plastic package is evaluated by applying the energy release rate criterion. The package crack formation depend on various parameters such as chip set, chip size, package thickness, package width, material properties and the moisture content etc. The effects of chip set and the other parameters were estimated during the analysis of package cracks which were located in the edge of the upper interface of the chip and the lower interlace of the die pad. From the results, it could be obtained that the more significant parameters to effect the chip set are chip width.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.946-949
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• 2002

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, The effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the head-disk interface using a particle injection system. It was found that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except for the particles of specific size and property. As a means to removed the particles of specific size, the concept of using a stepped taper at the leading edge of the slider is proposed.

• 한국IT서비스학회:학술대회논문집
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• 2003.05a
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• pp.623-628
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• 2003

제품의 개발 및 생산 과정에는 설계, 해석, 가공, 검사 등의 많은 부문이 서로 밀접하게 연계되어 있고 각 부문 간에는 각기 서로 다른 형태의 정보를 필요로 하기 때문에 이들의 유기적인 통합을 위해서는 각각의 응용 분야에서 요구되는 다양한 정보가 효과적으로 제공될 필요가 있다. 본 연구에서는 특징형상을 이용하여 설계 기능과 다른 응용 부분을 유기적으로 연계할 수 있는 알고리즘을 제시한다. ISO에서 진행 중인 STEP의 Form Feature을 기준으로 일반적인 분류를 하고 이를 기초로 특징형상을 인식하고자 하였다. 이를 위해 B-Rep 데이터로부터 Face-Edge Graph를 구성하고 다중 절점(Cut Node)을 인식하였으며, 본 연구를 바탕으로 하여 향후 몇 가지 단점을 보완하고 대상 영역을 확대시켜 감으로써 Computer-aided Design 시스템으로부터 얻어지는 3차원 형상 데이터로부터 Computer-aided Process Plan을 위해 필요한 특징형상을 컴퓨터에 의해 자동으로 추출하기 위한 발판을 구축할 수 있을 것이다.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.593-600
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• 2016

Operation properties, such as output power, beam radius, and crystal temperature rise were investigated in a diode-pumped edge-cooled monolithic Yb:YAG laser with ~ 4 W pumping level. The output power showed saturation behavior because of severe temperature rise and poor spatial overlapping between pump beam and lasing mode. Face cooling geometry by using a sapphire plate was also investigated. No apparent saturation behavior in output power was observed due to the reduced temperature rise, which could be attributed to efficient heat removal through the crystal-sapphire interface.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.473-476
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• 1987

Low temperature phosphorus-nitride CVD was newly developed for a high quality gate insulator on InP substrate. This film showed the Poole-Frenkel type conduction in high electric field with resistivity higher than $1{\times}10^{14}$ ohm-cm near the electric field of $1{\times}10^7\;volt/cm$. The C-V hysteresis width was very small as 0.17 volt. The density of interface trap states was $2{\times}10^{11}cm^{-2}ev^{-1}$ below the conduction band edge of InP substrate. Effective electron mobility was about $1200-1500\;cm^2/Vsec$ and showed the instability of PN-InP MISFETs drain current reduced less than 10 percent for the period $0.5-10^3sec$.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.5
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• pp.554-559
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• 2003

A newly developed contact angle measurement instrument by laser beam projection allows for rapid and direct determination of contact angles. The instrument may have a possibility to characterize newly developed nano-fibers. When the laser beam impinges on an edge of an interface of liquid and solid, projected beam were split across and made two straight lines on a tangent screen. From the result, it could measure the contact angle directly by reading the angle between two split beams. The purpose of this study was to prove reliability and reproducibility of the contact angle measurement instrument by laser beam projection compare to the conventional one by microscope through the comparative experiment and questionnaire. Test samples were selected by consideration of hydrophilic and hydrophobic, such as nylon 6 and polypropylene, respectively. The laser contact angle measurement has accurate, fast and convenient method to measure contact angle, and it can be a unique method to characterize nano-fibers.

• Korean Journal of Materials Research
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• v.2 no.5
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• pp.383-386
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• 1992

In deep anisotropic etching of (100)-oriented Si substrate, it could be observed that the non-uniformities existing near the etched-edge were caused by lattice defects and mechanical stress at the etching interface.

• Advances in materials Research
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• v.3 no.1
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• pp.271-281
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• 2014

The presence of cavities in the bone cement has a great importance for the transport of antibiotics, but its existence in this material can lead to its weakening by notch effect. The aim of this study allows providing a physical interpretation to the cavities interconnection by cracks observed experimentally. The most important stress of Von Mises is localized at the cement/bone interface near the free edge which is the seat of stress concentration. The presence and interaction of cavities in this site concentrate, by notch effect, stresses which tend to the tensile fracture stress of Bone cement.