• 한국진공학회지
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• 제16권1호
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• pp.40-45
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• 2007

본 연구에서는 광전자 소자에 폭넓게 사용되는 ZnCdSe 화합물 반도체의 end-point인 CdSe의 유전함수 spectrum을 Vacuum Ultra Violet spectroscopic ellipsometry(타원편광분석법) 측정하여 분석하였다. 측정 결과는 변수화 모델을 이용하여 분석하였으며 그 결과 6 eV 이상에 존재하는 전자전이점들을 확인할 수 있었고 CdSe의 Critical Point(CP) 구조를 수치화 함으로써 온도나 화합물 함량에 따른 광특성 의존성 연구 등에 활용될 수 있는 database를 확보하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2003년도 춘계공동학술대회논문집
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• pp.291-297
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• 2003

본 연구는 산업계 구조변화와 그에 따른 새로운 비즈니스 형태를 체계적으로 분류하고 해석하기 위한 이론과 개념을 수립하고 그것을 토대로 e-business를 포함한 새로운 비즈니스의 분류 프레임워크를 제안하는 것을 목적으로 한다. 제안한 모델은 비즈니스의 계층성에 주목한 비즈니스 계층(BL)의 개념, 업계를 연계하는 가치사슬(VC)의 개념, 그리고 실세계(혹은 실 주체)와 가상공간 세계(혹은 가상주체)의 개념을 상징 하는 R/V(Real/Virtual)의 개념을 기본 프레임으로 하여 구성되었며, 이러한 BL-VC-R/V의 조합을 통해 이론상 해당업게에서 존재할 수 있는 모든 비즈니스의 분류가 가능하다는 점을 보였다. 한편, 본 연구에서는 제안된 프레임워크의 개념을 토대로 e-business의 새로운 정의를 제시하였고, 산업에 본 모델을 적용하여 공간시장화에 따른 구조변화와 그에 따른 비즈니스 분류를 행하였다. 그리고, 비즈니스차원의 관점에서 최근에 거론되고 있는 e-Logistics를 새롭게 정의하였다.

• 한국항해항만학회지
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• 제27권4호
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• pp.389-395
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• 2003

본 연구는 산업계 구조변화와 그에 따른 새로운 비즈니스 형태를 체계적으로 분류하고 해석하기 위한 이론과 개념을 수립하고 그것을 토대로 e-business를 포함한 새로운 비즈니스의 분류 프레임워크를 제안하는 것을 목적으로 한다. 제안한 모델은 비즈니스의 계층성에 주목한 비즈니스 계층(BL)의 개념, 업계를 연계하는 가치사슬(VC)의 개념, 그리고 실세계(혹은 실 주체)와 가상공간 세계(혹은 가상주체)의 개념을 상징 하는 R/V(Real/Virtual)의 개념을 기본 프레임으로 하여 구성되었으며, 이러한 BL-VC-R/V의 조합을 통해 이론상 해당업계에서 존재할 수 있는 모든 비즈니스의 분류가 가능하다는 점을 보였다. 한편, 본 연구에서는 제안된 프레임워크의 개념을 토대로 e-business의 새로운 정의를 제시하였고, 산업에 본 모델을 적용하여 공간시장화에 따른 구조변화와 그에 따른 비즈니스 분류를 행하였다. 그리고, 비즈니스차원의 관점에서 최근에 거론되고 있는 e-Logistics를 새롭게 정의하였다.

• 한국세라믹학회지
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• 제53권1호
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• pp.43-49
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• 2016

This analyzed a Young's modulus (E), a thermal expansion coefficient (TEC, ${\beta}$) and a thermal conductivity (${\kappa}$) of the material with simple cubic particulate inclusion using two model structures: a parallel structure and a series structure of laminated layers. The derived ${\beta}$ equations were applied to calculate the ${\beta}$ value of the W-MgO system. The accuracy was higher for the series model structure than for the parallel model structure. Young's moduli ($E_c$) of sintered porous alumina compacts were theoretically related to the development of neck growth of grain boundary between sintered two particles and expressed as a function of porosity. The series structure model with cubic pores explained well the increased tendency of $E_c$ with neck growth rather than the parallel structure model. The thermal conductivity of the three phase system of alumina-mullite-pore was calculated by a theoretical equation developed in this research group, and compared with the experimental results. The pores in the sintered composite were treated as one phase. The measured thermal conductivity of the composite with 0.5-25% porosity (open and closed pores) was in accordance with the theoretical prediction based on the parallel structure model.

• KSTLE International Journal
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• 제6권1호
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• pp.1-7
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• 2005

Wear model for predicting the vehaviour of a depth is considered in this paper. It is deduced from the energy and volume based wear models such as the Archard equation and the workrate model. A new parameter of the equivalent depth ($D_e$= wear volume /worn area) is considered for the wear model of a depth prediction. A concenpt of a dissipated shear energy density is accommodated for in the suggested models. It is found that $D_e$ can distinguish the worn area shape. A cubic of $D_e$($D_e^3$) gives a better linear regression with the volume than that of the maximmum depth $D_{max}e$($D_{max}^3$) does. Both $D_{max}$ and $D_e$ are used for the presently suggested depth-based wear model. As a result, a wear depth profile can be simulated by a model using $D_{max}$. Wear resistance from the concern of an overall depth can be identified by the wear coefficient of the model using $D_e$.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.33-35
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• 2012

This study has been mainly motivated to numerically model the supercritical mixing and combustion processes encountered in the liquid propellant rocket engines. In the present approach, turbulence is represented by the extended k-e model. To account for the real fluid effects, the propellant mixture properties are calculated by using generalized cubic equation of state. In order to realistically represent the turbulence-chemistry interaction in the turbulent nonpremixed flames, the flamelet approach based on the real fluid flamelet library has been adopted. Based on numerical results, the detailed discussions are made for the effects of swirl number on flame structure of supercritical kerosene/LOx double swirl coaxial injector.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.81-82
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• 2013

This study has been mainly motivated to numerically model the supercritical mixing and combustion processes encountered in the liquid propellant rocket engines. In the present approach, turbulence is represented by the standard k-e model. To account for the real fluid effects, the propellant mixture properties are calculated by using generalized cubic equation of state. In order to realistically represent the turbulence-chemistry interaction in the turbulent nonpremixed flames, the flamelet approach based on the real fluid flamelet library has been adopted. Based on numerical results, the detailed discussions are made for the effects of swirl on flame structure of supercritical kerosene liquid propellant combustion.

• 한국안전학회지
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• 제13권1호
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• pp.70-76
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• 1998

The smoke filling process for the atrium space containing a fire source is simulated using two types of deterministic fire models : Zone model and Field model. The zone model used is the CFAST(version 1.6) model developed at the Building and Fire Research Laboratories, NIST in the USA. The field model is a self-developed fire field model based on Computational Fluid Dynamics(CFD) theories. This article is focused on finding out the smoke movement and temperature distribution in atrium space which is cubic in shape. A computational procedure for predicting velocity and temperature distribution in fire-induced flow is based on the solution, in finite volume method and non-staggered grid system, of 3-dimensional equations for the conservation of mass, momentum, energy, species and so forth. The fire model i. e. Zone model and Field model predicted similar results for the clear height and the smoke layer temperature.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1207-1212
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• 2004

A model for the phonon dispersion relationship for cubic zinc sulfide structure, for example SiC, is developed in terms of two unknown force constants. Born model that incorporates bond bending and bond stretching, is used for the force constants. The force constants are determined by fitting to experimental data. Using only the nearest-neighbor coupling results in $6{\times}6$ sized dynamic matrix. The eigenvalues of dynamics matrix for each wavenumber in 3-D ${\kappa}$ space correspond to frequencies, 3 for optical phonon and 3 for acoustic phonon, which is so-called dispersion relation (${\kappa}$-${\omega}$). The density of state is determined by counting the states for each frequency bin, and the properties such as specific heat and thermal conductivity can be obtained. The specific heat is estimated on this model and compared with experiment and other models, i.e. Debye model, Einstein model and combined Debye-Einstein model. In spite of the simple bond potential model, reasonable agreements are found.

• International Journal of Precision Engineering and Manufacturing
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• 제3권1호
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• pp.49-56
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• 2002

The Z-map is a special farm of discrete non-parametric representation in which the height values at grid points on the xy-plane are stored as a 2D array z[ij]. While the z-map is the simplest farm of representing sculptured surfaces and is the most versatile scheme for modeling non-parametric objects, its practical application in industry (eg, tool-path generation) has aroused much controversy over its weaknesses, namely its inaccuracy, singularity (eg, vertical wall), and some excessive storage needs. Much research or the application of the z-map can be found in various articles, however, research on the systematic analysis of sculptured surface shape representation via the z-map model is rather rare. Presented in this paper are the following: shape modeling power of the simple z-map model, exact (within tolerance) z-map representation of sculptured surfaces which have some feature-shapes such as vertical-walls and real sharp-edges by adopting some complementary z-map models, and some application examples.