• 한국과학교육학회지
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• 제9권2호
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• pp.13-27
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• 1989

A curriculum for teaching materials in Science Education was studied as a model for modified experiment on fundamental courses. Conscious effort can be made to desingn experiments that require minimum apparatus: that require low-cost equipment that can be made from cheap locally available materials. Computer-aided instruction programs at high school, freshman course level have been developed. The software package was consist of five programs: The program contains explanation and problems for the calculation of resonance energy, molecular structure, mole concept. Rutherford's experiment. thermodynamic processes. Special course equipment package explanation mole concept, Rutherford's experiment, thermodynamic processes. Special course were designed in Science Education with the understanding that to a certain extent science values would be covered in all of the modified experiments and program models.

• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.841-850
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• 1997

A simple molecular theory of mixtures is formulated based on the nonrandom two-fluid lattice-hole theory of fluids. The model is applicable to mixtures over a density range from zero to liquid density. Pure fluids can be completely characterized with only two molecular parameters and an additional binary interaction energy is required for a binary mixture. The thermodynamic properties of ternary and higher order mixtures are completely defined in terms of the pure fluid parameters and the binary interaction energies. The Quantitative prediction of vapor-liquid, and solid-vapor equilibria of various mixtures are demonstrated. The model is useful, in particular, for mixtures whose molecules differ greatly in size. For real mixtures, satisfactory agreements are resulted from experiment. Also, the equation of state (EOS) is characterized well, even the liquid-liquid equilibria behaviors of organic mixtures and polymer solutions with a temperature-dependent binary interaction energy parameter.

• Bulletin of the Korean Chemical Society
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• 제6권6호
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• pp.337-343
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• 1985

A statistical mechanical approach to elucidate the solvent effects on the high polymer solutions has been carried out on the basis of the simple model of liquids improved by Pak. In our works, the partition function of the polymer solutions is formulated by the lattice model and our simple treatment of liquid structures. For the ideal polymer solutions proposed by Flory, thermodynamic functions of the polymer solutions are obtained and equations of mixing properties and partial molar quantities are derived from the presented partition function of the polymer solutions. Partial molar quantities are calculated for the rubber solutions in carbon disulfide, benzene and carbon tetrachloride. Comparisons have been made between our equations and those of Flory's original paper for partial molar properties of the rubber-benzene system. Comparing the experimental data of the osmotic pressure of polystyrene-cyclohexane system with our calculated values and those of Flory's, our values fit to the agreeable degrees better than those of Flory's.

• Molecules and Cells
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• 제45권1호
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• pp.6-15
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• 2022

Phase separation is a thermodynamic process leading to the formation of compositionally distinct phases. For the past few years, numerous works have shown that biomolecular phase separation serves as biogenesis mechanisms of diverse intracellular condensates, and aberrant phase transitions are associated with disease states such as neurodegenerative diseases and cancers. Condensates exhibit rich phase behaviors including multiphase internal structuring, noise buffering, and compositional tunability. Recent studies have begun to uncover how a network of intermolecular interactions can give rise to various biophysical features of condensates. Here, we review phase behaviors of biomolecules, particularly with regard to regular solution models of binary and ternary mixtures. We discuss how these theoretical frameworks explain many aspects of the assembly, composition, and miscibility of diverse biomolecular phases, and highlight how a model-based approach can help elucidate the detailed thermodynamic principle for multicomponent intracellular phase separation.

• Korean Chemical Engineering Research
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• 제57권5호
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• pp.679-686
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• 2019

수용액으로부터 활성탄에 대한 아닐린 블루의 흡착 평형, 동역학 및 열역학적 특성을 초기농도, 접촉시간과 온도를 흡착변수로 하여 조사하였다. 아닐린 블루의 등온흡착은 Langmuir, Freundlich, Redlich-Peterson, Temkin 및 Dubinin-Radushkevich 모델을 통해 해석하였다. Langmuir 모델이 다른 모델들 보다 등온 데이터에 더 잘 맞았다. 평가된 Langmuir 분리계수($R_L=0.036{\sim}0.068$)는 활성탄에 의한 아닐린 블루의 흡착 공정이 효과적인 처리방법이 될 수 있음을 나타냈다. 흡착속도상수는 유사일차속도 모델, 유사이차속도 모델 및 입자내 확산 모델에 적용하여 구하였다. 활성탄에 대한 아닐린 블루의 흡착속도실험 결과는 유사이차 반응속도식에 잘 따랐다. 흡착 메카니즘은 입자내 확산 모델에 의해 경막 확산과 입자내 확산의 두 단계로 평가되었다. 흡착공정에 대한 깁스 자유에너지, 엔탈피 및 엔트로피 변화와 같은 열역학 파라미터들이 평가되었다. 엔탈피 변화(48.49 kJ/mol)은 흡착공정이 물리흡착이고 흡열반응임을 알려주었다. 깁스 자유 에너지는 온도가 올라갈수록 감소하였기 때문에 흡착반응은 온도가 올라갈수록 자발성이 더 높아졌다. 등량흡착열은 흡착제 표면의 에너지 불균일성 때문에 흡착제와 흡착질 사이에 상호작용이 있음을 나타내었다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.437-443
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• 1997

DYLAM and its related applications are reviewed in detail and found to have many favorable characteristics. Concerning human factor analysis, the study demonstrates that DYLAM methodology represents an appropriate tool to study man-machine behavior provided that DYLAM is used to model machine behavior and an appropriate operator interface human factor model is included. A hybrid model which is a synthesis of the DYLAM model, a system thermodynamic simulation model and a neural network predicative model, is implemented and used to analyze dynamically the CANDU pressurizer system.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1995년도 추계학술발표회 초록집
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• pp.75-81
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• 1995

DYLAM and its related applications are reviewed in detail and found to have many favourable characteristics. Concerning human factor analysis, the study demonstrates that DYLAM methodology represents an appropriate tool to study man-machine behaviour provided that DYLAM is used to model machine behaviour and an appropriate operator interface human factor model is included. A hybrid model which is a synthesis of the DYLAM model, a system thermodynamic simulation model and a neural network predicative model, is implemented and used to analyse dynamically the CANDU pressurizer system.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.611-617
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• 2021

The mechanical properties of α-Na₃(U_0.84(2),Na_0.16(2))O₄ have been researched using the first-principles calculations combined with the quasi-harmonic Debye model. The obtained lattice parameters agree well with the published experimental data. The results of elastic constants indicate that α-Na₃(U_0.84(2),Na_0.16(2))O₄ is mechanically stable. The polycrystalline moduli are predicted. The results show that the α-Na₃(U_0.84(2),Na_0.16(2))O₄ exhibits brittleness and possesses obvious elastic anisotropy. The hardness shows that it can be considered a "soft material". Furthermore, the Debye temperature θ_D and the minimum thermal conductivity k_min are also discussed, respectively. Finally, the thermal expansion coefficient α, isobaric heat capacity C_P and isochoric heat capacity C_V are evaluated through the quasi-harmonic Debye model.

• 항공우주시스템공학회지
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• 제18권3호
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• pp.8-16
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• 2024

수소는 매우 낮은 밀도를 갖기 때문에 화석연료와 동일한 수준의 에너지량을 저장하기 위해서는 기존과 다른 저장방식이 요구된다. 수소의 밀도를 높이는 방법으로는 수소를 액화하여 저장하는 방법이 있다. 하지만, 수소의 액화온도는 -252 ℃의 극저온이기 때문에 외부 열 유입에 의해 쉽게 기화된다. 액체수소가 기화되면 탱크 내부의 압력이 증가되는 자가증압 현상을 발생하므로, 탱크 설계 시 이 상승하는 압력을 잘 예측해야 한다. 따라서, 본 논문에서는 극저온 액체수소 연료탱크의 액체수소 충전 비율에 따른 내부 압력을 예측하였다. 탱크 내부의 압력 상승을 예측하기 위하여 1차원 열역학적 모델을 적용하였다. 열전달 모델은 열 유입, 액체수소의 기화, 연료 배출에 현상이 고려되었다. 최종적으로 연료탱크 내의 액체수소의 충전 비율에 따라 압력 상승 거동과 최대 상승 압력에 큰 차이가 있음을 확인하였다.

• Structural Engineering and Mechanics
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• 제89권2호
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• pp.103-119
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• 2024

The present research investigates the thermodynamically bending behavior of FG sandwich plates, laying on the Winkler/Pasternak/Kerr foundation with various boundary conditions, subjected to harmonic thermal load varying through thickness. The supposed FG sandwich plate has three layers with a ceramic core. The constituents' volume fractions of the lower and upper faces vary gradually in the direction of the FG sandwich plate thickness. This variation is performed according to various models: a Power law, Trigonometric, Viola-Tornabene, and the Exponential model, while the core is constantly homogeneous. The displacement field considered in the current work contains integral terms and fewer unknowns than other theories in the literature. The corresponding equations of motion are derived based on Hamilton's principle. The impact of the distribution model, scheme, aspect ratio, side-to-thickness ratio, boundary conditions, and elastic foundations on thermodynamic bending are examined in this study. The deflections obtained for the sandwich plate without elastic foundations have the lowest values for all boundary conditions. In addition, the minimum deflection values are obtained for the exponential volume fraction law model. The sandwich plate's non-dimensional deflection increases as the aspect ratio increases for all distribution models.