• Journal of Industrial Technology
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• v.9
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• pp.119-125
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• 1989

Lennard-Jones 유체 혹은 거의 구형에 가까운 분자들의 혼합물의 열역학적 성질을 예측하기 위한 용액이론이 유도되었다. 이 이론에는 에너지와 분자직경에 대한 두 개의 변수가 존재하며, 강구(hard sphere)를 중심으로 하여 동경함수(pair distribution function)를 확장시키는 교반이론(perturbation theory)에서 1/kT에 대한 일차와 이차계수의 관계로부터 얻어지는 혼합법칙을 이용하는 HSE이론과 달리 Orstein-Zernike결과와 일치되는 분자직경 변수를 먼저 구한 다음, 일차계수와 함께 얻어진 혼합법칙이 유도되었다. 이 방법으로 위 유체들의 혼합물에 적용시켰을 때, 원래의 HSE나 vdW-1의 방법보다 좋은 결과의 열역학적 성질을 예측할 수 있었다.

• Journal of the Korean Chemical Society
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• v.12 no.1
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• pp.26-31
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• 1968

이성분 용액에 대한 천이상태 이론의 적용 방법을 재고찰하여 이론적 보충을 하여주었으며, 이 새로운 방법에 따라서 $C_6H_{12}-CCl_4$계의 열역학적 성질들을 계산하였다. 또한 전의 방법에 따라서 계산된 $C_6H_6-C_6H_{12}$ 및 $C_6H_6-CCl_4$계의 열역학적 성질들도 재계산하였다. 이 방법에 따라서 계산된 열역학적 성질들을 측정치와 대단히 잘 맞는다.

• Nuclear Engineering and Technology
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• v.14 no.1
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• pp.10-16
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• 1982

The significant structure theory of liquids has been successfully applied to liquid gallium. In this work, we have assumed that two structures exist simultaneously in liquid gallium. One is considered as loosely close packed $\beta$-Ga-like structure and the other is the remainder of solid $\alpha$-Ga or $\alpha$-Ga-like structure. This two structural model is introduced to construct the liquid partition function. Using the partition function, the thermodynamic and transport properties are calculated over a wide temperature range. The calculated results are quite satisfactory when compared with the experimental results.

• Journal of Industrial Technology
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• v.17
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• pp.51-72
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• 1997

The sound velocity measurements can permit much higher precision than that obtainable in the direct PVT experiments in addition to producing static and dynamic properties simultaneously, and thus the study on the sound velocity has been considered as another important approach to a fundamental understanding and description of the structure of fluids. This review deals with what have been done on studies of the sound velocity for evaluating thermodynamic properties with an emphasis on the development of the methods to extract the thermodynamic properties from the experimental data on sound velocity.

• Elastomers and Composites
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• v.10 no.1
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• pp.28-32
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• 1975

• ETRI Journal
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• v.13 no.4
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• pp.42-51
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• 1991

MBE 성장시 기판 표면에서의 성장과정을 운동론적 지배과정과 열역학적 지배과정으로 나누어 성장모델을 제시하였으며, 화학적 평형상태에서의 열역학이 III-V compound의 성장속도와 composition 에 미치는 영향을 기존의 보고된 결과 데이터와 비교 분석하였다. 특히 miscibility gap 내에 존재하는 III-V ternary compound의 경우 박막의 성질 및 소자의 특성에 영향을 미치는 alloy clustering은 저온 성장시 surface kinetics에 의해, 고온성장시에는 열역학적 spinodal decomposition에 의해 결정됨을 알수 있었다. 열역학적 모델에서는 기판과 layer사이의 lattice mismatch와 재료의 elastic coefficient의 함수인 additive strain Gibbs free energy, 그리고 ternary solid solution의 regular behavior를 가정하여 ternary alloy의 mixing에 기인한 excess Gibbs free energy를 고려하였다.

• Journal of the Korean Chemical Society
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• v.16 no.5
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• pp.265-270
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• 1972

The aqueous solutions of aliphatic and aromatic hydrocarbons have been studied on the basis of the significant structure theory of liquid water proposed by Jhon, et al. The thermodynamic properties such as Helmholtz free energy, internal energy entropy, and heat capacity have been calculated. The results show good agreements with the experiments in the literature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.685-690
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• 2008

In numerically evaluating the thermal performance of the heat exchanger, numerical values of thermodynamic properties such as temperature, pressure, specific volume, enthalpy and entropy are required. But the steam table or diagram itself cannot be directly used without modelling. In this study the applicability of neural networks in modelling superheated water vapor was examined. The multi-layer neural networks consist of an input layer with 2 nodes, two hidden layers with 15 and 25 nodes respectively and an output layer with 3 nodes. Quadratic spline interpolation was also applied for comparison. Neural networks model revealed smaller percentage error compared with spline interpolation. From this result, it is confirmed that the neural networks could be a powerful method in modelling the superheated water vapor.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.308-315
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• 1991

The structure and thermodynamic properties of body centered cubic structure of simple Coulombic liquids are computed from the perturbation theory for one-component plasma. A comparison of perturbation theory (PT) and Monte Carlo (MC) simulation shows excellent agreement. The hardsphere perturbation theory is applicable to a long-range attractive system, such as the one-component plasma. A comparison of the radial distribution function (g(r)) and the structure factor (S(q)) for PT data and MC data shows agreement. Thus the perturbation theory is an applicable method to explain the structure and thermodynamic properties of Coulomb liquids.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.677-680
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• 2005

In numerical analysis on the thermal performance of the heat exchanger with phase change fluids, the numerical values of thermodynamic properties are needed. But the steam table should be modeled properly as the direct use of thermodynamic properties of the steam table is impossible. In this study the function approximation characteristics of neural networks was used in modeling the saturated vapor region of refrigerant R12. The neural network consists of one input layer with one node, two hidden layers with 10 and 20 nodes each and one output layer with 7 nodes. Input can be both saturation temperature and saturation pressure and two cases were examined. The proposed model gives percentage error of ${\pm}$0.005% for enthalpy and entropy, ${\pm}$0.02% for specific volume and ${\pm}$0.02% for saturation pressure and saturation temperature except several points. From this results neural network could be a powerful method in function approximation of saturated vapor region of R12.