• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.120-125
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• 1996

영광 3,4호기 시운전시 저출력에서 증기발생기 수위 자동 조절이 어려웠던점을 바탕으로 급수 조절밸브의 용량을 검토하여 급수조절밸브의 최적 용량 계산을 하였다. 급수조절밸브의 성능을 모사하기 위해 계통성능해석 전산코드인 LTC 코드를 이용하였다. 급수조절밸브의 최적 용량 계산 결과 기존의 경우보다 용량이 증가되었으며 LTC 코드로 성능을 모사하여 분석한 결과 기존의 저출력 운전시 발생하였던 문제점들이 해결될 수 있을 것으로 판단되었다.

• Journal of the Korean Society of Visualization
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• v.2 no.2
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• pp.20-24
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• 2004

Recent advances in CFD technique along with a rapid growth of computer resources provide valuable opportunities for developing an accurate way of visualizing turbulent structures. Not only this visualization technique made it possible to check the validity of many of theoretical achievements of the past but also it pushes the current turbulence research to a new paradigm. A brief history of visualization study will be summarized and discussed.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.82-94
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• 2017

본 연구에서는 고분자의 해밀토니안을 Q-state Potts-Model로 근사하여, 2, 3차원 형태의 선형 고분자 시스템을 모사하고자 한다. 고분자 외부에서 힘이 작용하고 있는 경우와 아닌 경우에 대하여 전산모사 결과를 바탕으로 고분자의 크기의 경향성을 확인하였다. 그 결과, 흔히 사용되는 Flory's Theory와 달리 고분자의 대표적인 특성인 지수(exponent)에 대하여 더 유동적인 관계식을 얻어낼 수가 있었다. 이를 바탕으로, 고분자에서 흔히 사용되고 있는 scaling argument가 잘 적용되는지를 확인해보았으며, 그 결과 일부의 경우에서만 성립함을 확인할 수 있었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.859-864
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• 1995

중수형발전로의 가동에 따라 중수는 삼중수소로 오염된다 오염된 중수의 정화에 적합한 공정으로 평가되는 기액촉매교환과 초저온증류공정으로 이루어진 촉매복합공정에 대하여 탑내의 유속비 및 이론단수의 변화에 따른 촉매탑과 증류탑에서의 삼중수소 제거율 및 농축률 그리고 탑내의 수소동위원소의 농도분포변화를 Newton-Raphson 방법을 사용하여 전산모사를 수행하여 구하였다. 이러한 해석은 본격적 최적화 설계의 기초입력자료로 활용될 것이다.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.615-619
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• 2009

(+)-$Tr{\ddot{o}}ger$'s base in $Tr{\ddot{o}}ger$'s base racemates that inhibits thromboxane A2($T{\times}A2$) synthase has been used to treat arteriosclerosis. Separation of (+)-$Tr{\ddot{o}}ger$'s base by chromatography has become a major concern. However separation experiments of (+)-$Tr{\ddot{o}}ger$'s base need time and consumables so that simulation with Aspen Chromatography could save time and costs by predicting the efficiency of separation. Injection amount and eluent flow rate were varied to compare the resolutions and yields of TB(-) and TB(+). Highest resolution and yield were attained at the eluent rate of 0.25 mL/min. Isotherms representing the relationship between mobile phase concentration and stationary phase concentration were changed to get the best separation with Ideal Adsorbed Solution(IAS) Statistical Lanmuir isotherms.

• Journal of the Korean Vacuum Society
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• v.18 no.6
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• pp.426-434
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• 2009

A global simulation of $SiH_4/H_2$ discharge is conducted in a planar-type inductively coupled plasma (ICP) discharge. We numerically solve a set of spatially averaged fluid equations for electrons, positive ions, negative ions, neutrals, and radicals. Absorbed power by electrons is determined by an analytic electron heating theory including the anomalous skin effect. Also, we investigate functional dependence of various discharge quantities such as the densities of various species and the temperature of electron on external controllable parameters such as ratio between $SiH_4$ and $H_2$, power and pressure.

• Journal of the Korean Vacuum Society
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• v.21 no.1
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• pp.55-61
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• 2012

We fabricated a-Si:H thin-film solar cell using the two-dimensional (2D) periodic patterned glass substrate. The use of a 3D periodic texture rather than a randomly texture at surface of TCO can result in higher short circuit current densities ($J_{sc}$). In order to analyze the optical effect of patterning glasses, ray-tracing simulations were performed. Also, p-i-n cells were deposited on patterned glasses as substrate by PECVD. UV-Vis spectroscopy, light I-V measurement were carried out for the optoelectronic characterization. The anti-reflective and light-trapping performance of patterning glass substrate was investigated by a comparison of experimental results with numerical simulations.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.215-221
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• 2002

Epitaxial Si layers were deposited on (100) Si substrates by hot-wall chemical vapor deposition (CVD) technique using the $SiH_2Cl_2/H_2$chemistry. Thermochemical calculations of the Si-H-Cl system were carried out to predict the window of actual Si deposition process and to investigate the effects of process variables (i.e., deposition temperature, reactor pressure, and input gas molar ratio ($H_2/SiH_2Cl_2$)) on the epitaxial growth. The calculated results were in good agreement with the experiment. Optimum process conditions were found to be the deposition temperature of 850~$950^{\circ}C$, the reactor pressure of 2~5 Torr, and the input gas molar ratio ($H_2/SiH_2Cl_2$) of 30~70, providing device-quality epitaxial layers.

• KSBB Journal
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• v.14 no.3
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• pp.371-376
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• 1999

Simulation of preparative protein chromatography becomes necessary for separation as well as optimal operation. A mathematical model describing the behavior of elution peaks in preparative protein chromatography for single and binary component separation was solved numerically using a PDEsolver Macsyma$^{\circledR}$(Macsyma Inc., Arlington, MA, U.S.A.). Band profiles were calculated with the equilibrium-dispersive model of chromatography. The effects of the sample volume, concentrations of solutes in the sample, flow velocity and column length on the band profile of the elution peaks are discussed. The results in this paper suggest the model simulation for the binary mixture can be extended to multicomponent separations.

• Progress in Medical Physics
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• v.26 no.1
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• pp.36-41
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• 2015

The Monte Carlo based dose calculation program for stereotactic body radiotherapy was developed in this study. The Geant4 toolkit widely used in the radiotherapy was used for this study. The photon energy spectrum of the medical linac studied in the previous research was applied for the patient dose calculations. The geometry of the radiation fields defined by multi-leaf collimators were taken into account in the PrimaryGeneratorAction class of the Geant4 code. The total of 8 fields were demonstrated in the patient dose calculations, where rotation matrix as a function of gantry angle was used for the determination of the source positions. The DicomHandler class converted the binary file format of the DICOM data containing the matrix number, pixel size, endian type, HU number, bit size, padding value and high bits order to the ASCII file format. The patient phantom was constructed using the converted ASCII file. The EGSnrc code was used to compare the calculation efficiency of the material data.