• Journal of the Korean Physical Society
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• 제73권10호
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• pp.1473-1478
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• 2018

In this study, we have developed a simple and cost-effective method to prevent edge bead formation by covering the edge of a chip-level substrate with heat-resistant tape during patterning using SU-8. Edge beads are a fundamental problem in photoresists and are particularly notable in high-viscosity fluids and thick coatings. Edge beads can give rise to an air gap between the substrate and the patterning mask during UV exposure, which results in non-uniform patterns. Furthermore, the sample may break since the edge bead is in contact with the mask. In particular, the SU-8 coating thickness of the chip-level substrates used in MEMS or BioMEMS may not be properly controlled because of the presence of edge beads. The proposed method to solve the edge bead problem can be easily and economically utilized without the need for a special device or chemicals. This method is simple and prevents edge bead formation on the sample substrate. Despite the small loss in the taping area, the uniformity of the SU-8 coating is improved from 50.9% to 5.6%.

• 한국지반공학회논문집
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• 제23권10호
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• pp.23-31
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• 2007

상대밀도는 사질토의 역학적 특성을 나타내는 중요한 요소 중의 하나이지만 아직까지도 최대 및 최소 상대밀도를 결정하는 방법이 명확하게 규정되지 않았다. 최대 및 최소상대밀도를 결정하는 방법은 많은 학자들에 의해 연구되었으나, 기존의 방법들은 시간과 노력이 많이 소요될 뿐만 아니라, 특히 최대상대밀도는 실험방법에 따라서 상당한 차이를 보여주고 있다. 이 연구에서는 기존 방법으로 구한 최대상대밀도와 큰 오차를 보이지 않으면서도 간편하고 실질적으로 이용하기 편리한 간편법을 제안하고자 한다. 실험은 타격수와 층수를 달리해 가면서 작은 몰드를 사용하여 실시하였으며, 실험결과를 Bowles 방법과 비교하였다.

• 한국도로학회논문집
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• 제14권2호
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• pp.63-72
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• 2012

가로 및 교차로에 설치된 단순입체시설의 현행 분석기법은 시설을 이용하는 주교통류를 분석대상에 포함시키지 않고 있어 불합리한 도로 및 신호운영을 유도하여 엇갈림현상, 병목현상과 같은 도로의 혼잡을 야기한다. 이러한 여건에도 불구하고 단순 입체시설을 이용하는 교통류 분석기법의 연구가 거의 수행된 바 없다. 또한 개략적으로 제시되어 있는 설정기준 역시 여러 가지 도로 및 교통조건을 반영하지 못하고 있는 실정으로, 단순입체시설이 포함된 교차로분석 시 지체도가 과소 추정되는 경향이 있다. 그러므로 본 연구는 도시내 입체시설의 효과를 파악하기 위한 선행과정으로서 대상시설의 효과를 파악할 수 있도록 입체시설의 분석기법을 개발하고 분석교차점의 적정간격을 응용하는데 그 목적이 있다. 본 연구는 다음과 같이 수행하였다. (1) 기존 분석기법의 문제점 제기, (2) 새로운 분석기법의 정립, (3) 사례지역의 적용 및 비교검정, (4) 분합류구간의 적정간격에 대한 민감도 분석을 수행한다. 연구결과, 본 연구에서 제시한 분석기법은 기존 분석기법의 모호한 부분을 명확히 하고 합리적인 결과를 추정할 수 있었다. 또한 그 분석기법을 응용하여 분합류구간에 대한 적정간격을 추정한 결과, 본선에서는 65m, 측도에서는 45m로 나타나 최소한 그 이상의 위치에 접속지점을 설치하는 것이 타당하다고 판단된다. 본 연구의 수행으로 얻어지는 가치는 다음과 같다. (1) 당해 시설에 대한 선행연구 또는 분석방법이 없었으므로 대상시설물로 인한 파급효과를 파악할 수 있다. (2) 본 연구의 분석기법은 기존 교차로의 분석방법을 차용함으로써 새로운 분석방법을 숙지하지 않아도 용이한 분석이 가능하다. (3) 본 연구에서 제시한 분석기법에 의하면 기존에 제외된 통과교통량을 포함시켜 분석할 수 있다. 이러한 방법을 통해 교차로 및 가로분석 시에 현황과 동떨어질 수 있는 결과에 대한 오류를 최소화할 수 있다. (4) 새로운 분석기법을 이용하면 신설 또는 기존 시설물에 대한 문제점을 도출하여 도로운영 및 신호운영 등의 개선방안을 제시할 수 있다.

• 소음진동
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• 제9권5호
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• pp.914-921
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• 1999

There are many theoretical investigations to analyze higher order mode of reactive type single expansion chambers with offset inlet/outlet locations. But the conventional method has the restriction that the ratio between the area of inlet(or outlet) pipe and that of chamber must be natural number. In the paper, a new method was suggested to apply the Kim's method to silencer with circular cross-section. Not only the offset location but also the magnitude of cross-section area of inlet/outlet pipe can be considered by the suggested method. The predictions by this new method also compared with those by the finite element method and Munjal's method in order to verify the accuracy of the suggested method presented here.

• Earthquakes and Structures
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• 제16권2호
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• pp.129-139
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• 2019

This paper develops a new method for estimating the elastic-plastic buckling strength of the truss structures under the static and seismic loads. Firstly, a new method for estimating the buckling strength of the truss structures was derived based on the buckling strength of the representative member considering the parameters, such as the structure configurations, boundary conditions, etc. Secondly, the new method was verified through the buckling strength estimation and the finite element method (FEM) analysis of the single member models, portal frame models and simple truss models. Finally, the method was applied to evaluate the buckling strength of a simple truss structure under seismic load, and the failure loads between the proposed method and the FEM were analyzed reasonably. The results show that the new method is feasible and reliable for structure engineers to estimate the buckling strengths of the truss structures under the static loads and seismic loads.

• 한국생산제조학회지
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• 제9권2호
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• pp.112-118
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• 2000

This paper deals with the application of sensitivity method to the parameter estimation for the dynamic analysis of gener-al mechanical system. In this procedure we take the derivatives of the given system with respect to a certain parameter and use this information to implement the steepest descent method. This paper will give two examples of this technique applied to simple vehicle models. This paper will give two examples of this technique applied to simple vehicle models. Simulation results show excellent convergence and accuracy of parameter estimates.

• 한국자동차공학회논문집
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• 제3권1호
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• pp.129-135
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• 1995

This study aims to compare the heat release calculated using the ensemble average of pressure data with the heat release calculated using the least squares method for pressure data. This paper propose a heat release computation method that can analyze the most correct, straight and simple method to analyse combustion phenomenon. In conclusion, we found that the least squares method of third-order was the best computational method for heat release calculation.

• Journal of Oral Medicine and Pain
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• 제20권2호
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• pp.515-528
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• 1995

The human genomic deoxyribonucleic acid(DNA) was extracted from the pulp, dentin of 22 teeth by clelex, phenol methods. Samples of the tooth-derived DNA were amplified by polymerase chain reaction(PCR), electrophosed for sex determination by detection of X-Y homologus amelogenin gene and D1S80 locus detection The following results have been achieved. 1. Chelex and phenol method are effective to sex determination in the pulp and dentin 2. Chelex method is not suitable for detection of D1S80 locus. 3. Concentration and purity of DNA for teeth using chelex method is lower than using phenol method. From the above investigation, chelex method is simple, rapid for sex determination, but it is not suitable for detection of VNTRs.

• 소성∙가공
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• 제6권3호
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• pp.233-238
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• 1997

The estimation of the forming force required for metal forming process is unavoidable for selecting suitable machine and dimensioning die and punch parts. For this purpose the upper-bound method turns out to be very practical in simple two-dimensional cases under well-known boundary conditions. However, the application of this method for complicated two-or three-dimentional cases is very limited or practically impossible. The modified application of FEM in a manner of applying the upper bound method(the so-called Upper-bound Finite Element Simulation Method) fortunately provides the posibility of getting important information about the forming process in a simple and quick way before realizing the process on the machine. It is expected to function successfully even in three-dimentional cases. The application procedure has been explained for two-dimensional cases and its usefulness shown.

• 소음진동
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• 제10권6호
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• pp.998-1008
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• 2000

The continuous circular cylindrical shells are widely used for the high performance structures of aircraft, spacecraft, missile, nuclear fuel rod shell etc.. In this paper, a method for the free vibration analysis of the continuous circular cylindrical shells with the multiple simple supports is developed by using the receptance method. With this method, the vibrational characteristics of the continuous system is analyzed by considering as a combined structure. The system receptance is also derided by the application of the equilibrium of forces and the continuity of displacements at the support points. The natural frequencies and mode shapes are calculated numerically and they are compared with the FEM results to improve the reliability of analytical solution. Numerical results on the 4-equal-span continuous circular cylindrical shell are presented in this paper.