• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.289-292
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• 2007

To prevent the damage of glass lens molds and deterioration of glass lenses using in progressive GMP process, a thermal stress and a deformation of the glass lens molds at forming temperature should be considered in the design step. In this study, as a fundamental study to develop a multi cavity mold used in an aspheric glass lens molding, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally, using analysis results, we estimated the thermal stress in a glass lens mold and predicted a modified height of guide ring that determines the forming height of a glass lens.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.229-232
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• 2008

The Central East Sea Tsunami caused huge damage to the eastern coast of the Korean Peninsula, eapecially Imwon port was damaged relatively strongly beacause of water depth variation which makes the wave concentration on this port. there are many virtual tsunami in east sea which has a possibility of happening. So, it is very important to expect the region which may be damaged by vritual tsunmis. In this study, modified dispersion-correction terms are used. The modified scheme has the advantage of using the constant spatial grid size and time step size even in real topography. Dynamic linking technique and staggered grid system are used. Using this model some cases of virtual tsunami was simulated and check the region which is occured maximum wave heights on the eastern sea of the Korean peninsula.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.93-94
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• 2005

Cu metallization using electrochemical plating(ECP) has played an important role in back end of line(BEOL) interconnect formation. In this work, we studied the optimized copper thickness using Bottom-up Gap-fill in Cu ECP, which is closely related with the pattern dependencies in Cu ECP and Cu dual damascene process at 0.13 ${\mu}m$ technology node. In order to select an optimized Cu ECP thickness, we examined Cu ECP bulge, Cu CMP dishing and electrical properties of via hole and line trench over dual damascene patterned wafers split into different ECP Cu thickness.

• Journal of Welding and Joining
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• 제31권6호
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• pp.107-111
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• 2013

The welding distortion is caused by welding heat in the structures which are widely used in shipbuilding and automotive industries, thus many researchers have proposed such methods to control the welding distortion through trials and numerical studies. The welding distortion has been the main cause of low productivity due to the structural strength degradation, apparent flaw, additional deformation caused by the process followed the current assembly step, and the increase of correction workload. The deformation of fillet welding is investigated in this study, and the influence of the rib height on the welding distortion is verified through the actual experiment. And the numerical analysis model using the FE software MSC.marc for analysis of welding distortion is proposed.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.47-52
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• 1999

Theoretical and experimental studies on burr formation and deburring in many manufacturing processes have been actively pursued. Though micro-drilling has become more important in the production of precision parts such as PCB, air bearing, camera and nozzle, most studies on drilling burr formation have focused on the conventional drilling process. This paper describes burr formation process and the effect of cutting conditions such as spindle speed, feedrate and drilling depth per one step on burr formation in drilling A6061 with drills of diameter 1.0mm and 0.6mm. Experimental results showed that burr with cap were formed at relatively low feedrates, while petal burrs with several large burr fragments were formed at high feedrates. Burr height appeared to increase at the hight feedrates and lower spindle speeds. The effect of final cutting depth on burr height was negligible.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1720-1723
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• 2000

Boron doped conducting diamond thin film were grown on Si substrate by microwave plasma chemical vapor deposition from a gaseous feed of hydrogen, acetone/methanol and solid boron. The doping level of boron was controlled from 0ppm to $10^4$ppm (B/C). The Si substrate was tilted ca. 10$^{\circ}$ to make Si substrate have different height and temperature. Experimental results show that same condition but different temperature of Si substrate by height made different crystalline of diamond thin film. There were appeared 3$\sim$4 step of different crystalline morphology of diamond. To characterize the boron-doped diamond thin film, Raman spectroscopy was used for identification of crystallinity. To survey surface morphology, microscope was used. Grain size was changed gradually by different temperature due to different height. The Raman spectrum of film exhibited a sharp peak at 1334$cm^{-1}$, which is characteristic of crystalline diamond. The lower position of diamond film position, the more non-diamond component peak appeared near 1550$cm^{-1}$.

• 교육시설
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• 제14권3호
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• pp.17-26
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• 2007

This paper reviews KSG2010(Korean Industrial Standard for Student's Desk and Chair) compared to student's body size and suggests its new design guideline. It is found that the chairs are too high to sit straight up, and it is not easy to sit at student's ease because of backbone rest bar not existed in a right place. It is also found that the desks are too high to sit at desk to accept student legs under a drawer. So student's visibility range becomes decreased and it produces a harmful posture for eye protection. This paper also found that step number of student's desks and chairs needs to expand to 12 different steps inserted 5 steps between the existing 7 steps. A reason is that there is gap between the sizes of desk and chair and human height and width. Another reasons is that it is difficult to arrange desks and chairs appropriated to student body sizes in a class room.

• 한국정보처리학회논문지
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• 제7권3호
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• pp.935-942
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• 2000

In this paper we introduce a fast simplification algorithm for terrain height fields to produce a triangulated irregular network, based on the greedy insertion algorithm in [1,4,5]. Our algorithm partitions a terrain height data into rectangular blocks with the same size ad simplifies blocks one by one with the greedy insertion algorithm. Our algorithm references only to the points and the triangles withing each current block for adding a point into the triangulation. Therefore, the algorithm runs faster than the greedy insertion algorithm, which references all input points and triangles in the terrain. Our experiment shows that partitioning method runs from 4 to more than 20 times faster, and it approximates test height fields as accurately as the greedy insertion algorithms. Most greedy insertion algorithms suffer from elongated triangles that usually appear near the boundaries. However, we insert the four corner points into each block to produce the base triangulation of the block before the point addition step begins so that elongated triangles could not appear in th simplified terrain.

• 한국광학회지
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• 제22권3호
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• pp.129-133
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• 2011

2-파장 홀로그래피에서 수정된 화인 맵을 이용하여 2-파장 홀로그래피에서 발생하는 잡음 증폭현상을 줄이는 연구를 수행하였다. 일반 적인 화인 맵은 측정체의 단차가 2-파장 홀로그래피에 사용되는 광원의 파장보다 작은 경우에는 잡음을 잘 줄일 수 있으나, 단차가 파장 보다 큰 경우에는 측정 결과에 영향을 주어 잘못 된 측정 결과를 보인다. 이러한 오차를 줄이기 위하여 수정된 화인 맵을 이용하였으며, 그 결과 측정체의 단차가 파장 보다 큰 경우에도 측정에 영향을 주지 않고 잡음을 줄일 수 있음을 확인 하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2378-2383
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• 2007

Direct Numerical Simulation was carried out to predict mass transfer in turbulent flow around a rotating stepped cylinder. This investigation is a follow-up study of Nesic et al. [Corrosion, Vol. 56, No. 10, pp. 1005 - 1014] The original motivation of this work stemmed from the efforts to design a simple device which can generate flows of high turbulence intensity at low cost for corrosion researchers. Two cases were considered; Sc=1 and 10 both at Re=335. Here, Sc and Re stand for Schmidt number and Reynolds number, respectively, based on the step height and the surface speed of the cylinder upstream the step. Main focus was placed on the correlation between turbulent fluctuation and concentration field. The spatio-temporal evolution of concentration field is discussed. The numerical results are qualitatively compared with those of the experiment conducted with the same flow configuration.