• 한국결정성장학회지
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• 제25권6호
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• pp.285-289
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• 2015

프로브카드의 소형화, 고기능화. 고집화에 따라 고강도 무수축 기판에 레이저 가공 공정을 이용한 미세 홀 천공에 대한 관심이 높아지고 있다. 그린 상태에서 레이저 펀처로 미세 홀을 천공 시 테이퍼 현상이 중요한 공정 문제가 되고 있다. Entrance hole과 exit hole의 크기 차이는 홀 크기가 작을수록 커지고, 홀 크기가 커질수록 작아지는 경향을 나타내었다. 테이퍼 현상을 개선하기 위해 second hole 가공 공정을 적용하였다. 기판의 두께가 $380{\mu}m$인 기판 상에 $80{\mu}m$ 홀 천공시 최적의 second hole 크기를 찾기 위해 $70{\sim}79{\mu}m$ 홀을 천공하였을 경우 $76{\mu}m$와 $77{\mu}m$에서 테이퍼는 11.9 %로 가장 낮게 나타났다. 천공된 무수축 기판을 소결한 후에는 테이퍼가 7 %로 개선되었다. First hole 크기와 비교하였을 때 second hole 크기는 first hole 크기의 약 95~97 % 일 때 테이퍼가 가장 적었다.

• 한국정밀공학회지
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• 제21권6호
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• pp.131-138
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• 2004

The objective of this paper is to decide optimal location of a pin-hole to minimize stress concentration around the hole in a rotating disc. The focus of this investigation is to evaluate the effect of pin-hole on stress distribution around the hole using optimum design technique and finite element analysis. Design variables are the radial and the angular location of pin-hole from center of the hole and objective function is the maximum stress around hole in a rotating disc. Using first order method of optimization technique, we found that the maximum equivalent stress around the hole with optimized pin-hole could be reduced by 15.1% compared to that without pin-hole.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.574-578
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• 2003

The objective of this paper is to decide optimal location of pin-hole to minimize stress concenstation around hole in rotating disc. The focus of this investigation is to evaluate the effect of pin-hole for stress distribution around hole using optimum design technic and finite element analysis. Design variables are radial and angular location of pin-hole from center of hole, objective function is maximum stress around hole in rotating disc. We use first order method of optimization technic.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.242-242
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• 2009

Fabrication of Anodic aluminum oxide under DC vias condition has been studied. When bias and time of anodic aluminum oxide process change, the hole distance and diameter size change. Comparison of fabricated AAO between AC vias and DC vias condition has been studied in this experiment. The first and second anodization of one aluminum is done by using DC and AC power supplier. And first and second anodization of another aluminum is done by DC power supplier. The size of the aluminum is $1cm{\times}3cm$, and second anodic aluminum oxide process takes about 45min. It is found that the hexagonal shape appears on the surface of the AAO. AC power source can fabricate aao which have a nano hole array. We can see that the hole on the surface of the AC vias has a better rounded hole than DC vias AAO. we need more data so we can get characteristic about AC power generated AAO.

• Journal of Welding and Joining
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• 제8권4호
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• pp.76-82
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• 1990

Lots of research works have been done to improve the accuracy of the hole drilling method to measure residual stress by many investigators. In this study, first, size effect of specimen was analyzed based on the solution of hole in a strip under tension. If the ratio of hole diameter tothe strip width is less than 0.2, the stress distribution around hold may be given from the solution of hole in an infinite plate. Second, the residual stress above $0.6{\sigma}_y$(yield stress) may be measured less than the actual stress by 10-15 percent. Third, eccentricity of hole relative to the rosette center effects on the accuracy of residual stress measurements by 10 percent. The error due to eccentricity of hole can be corrected by the iteration method or the direct method.

• 소음진동
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• 제4권3호
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• pp.283-295
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• 1994

This work presents the experimental and finite element analysis results for the free vibration of 4 edges clamped, isotropic square plates with 2 collinear circular holes. Natural frequencies of finite element analysis are obtained for the complete square plate, the square plates with a central circular hole and the square plates with 2 collinear circulare holes. And natural frequencies are experimentally measured for the complete square plate, the square plate with a central circular hole(d = 150 mm) and the square plates with 2 collinear circular holes. Agreement between experimental and FEM results is excellent. Mode shapes in special case are presented. The conclusions of the study are as follows. There is little variation of nondimensional frequency parameters for the first six mode when the aspect ratio of circular hole is less than 1/6 in the isotropic square plates with 2 collinear circular holes. And the first nondimensional frequency parameter doesn't vary as the aspect ratio of circular hole increase.

• Structural Engineering and Mechanics
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• 제51권1호
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• pp.111-130
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• 2014

The aim of this study is to investigate the effects of the beam aspect ratio(L/h), hole diameter, hole location and stacking layer sequence ($[0/45/-45/90]_s$, $[45/0/-45/90]_s$ and $[90/45/-45/0]_s$) on natural frequencies of glass/epoxy perforated beams under room and high (40, 60, 80, and $100^{\circ}C$) temperatures for the common clamped-free boundary conditions (cantilever beam). The first three out of plane bending free vibration of symmetric laminated beams is studied by Timoshenko's first order shear deformation theory. For the numerical analyses, ANSYS 13.0 software package is utilized. The results show that the hole diameter, stacking layer sequence and hole location have important effect especially on the second and third mode natural frequency values for the short beams and the high temperatures affects the natural frequency values significantly. The results are presented in tabular and graphical form.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권1호
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• pp.45-53
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• 2013

In this paper, we analyze the failure mechanism of the washer pump to find what is the failure cause in the road environment. The statistics show the field common failure mode is inner corrosion. The failure mechanism is assumed that the inner part of washer pump is corroded due to inflow of moisture through vent hole. To prevent the failure, we can think a method that is covering the vent hole. In general, the vent hole is designed to play an important role in an automobile parts. So, we need to prove the vent hole is not necessary. The first purpose of this paper is to make sure that the vent hole does not affect the durability of washer pump using the analysis of operating condition. The second purpose is to compare the durability properties if the vent hole is covered.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제8권1호
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• pp.81-92
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• 2004

Muskhelishvili's complex variable method has been applied to derive exact and closed expressions for Gaursat's functions for the first and second fundamental problems of the infinite plate weakened by a curvilinear hole which is conformally mapped on the domain outside the unit circle by means of rational mapping function. The hole having three poles. The previous work of the authers in this domain is considered as special cases of this work.

• 전자공학회논문지A
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• 제31A권6호
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• pp.134-142
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• 1994

A kink due to the lasing of the first transverse mode in laser diodes is investigated using rate equations based on the spatial hole burning model. An analytic expression for the kink power is derived and the result agrees well with experimental results. It is also shown that the position of a kink can be identified in the electrical derivative characteristics as well as in light output vs, current characteristics.