• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2931-2936
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• 2013

This paper presents results for the calculation of transport properties of noble gases (He, Ne, Ar, Kr, and Xe) at 273.15 K and 1.00 atm using equilibrium molecular dynamics (EMD) simulations through a Lennard-Jones (LJ) intermolecular potential. We have utilized the revised Green-Kubo formulas for the stress (SAC) and the heat-flux auto-correlation (HFAC) functions to estimate the viscosities (${\eta}$) and thermal conductivities (${\lambda}$) of noble gases. The original Green-Kubo formula was employed for diffusion coefficients (D). The results for transport properties (D, ${\eta}$, and ${\lambda}$) of noble gases at 273.15 and 1.00 atm obtained from our EMD simulations are in a good agreement with the rigorous results of the kinetic theory and the experimental data. The radial distribution functions, mean square displacements, and velocity auto-correlation functions of noble gases are remarkably different from those of liquid argon at 94.4 K and 1.374 $g/cm^3$.

• Coupled systems mechanics
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• 제6권1호
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• pp.75-96
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• 2017

As electron donor/acceptor materials for organic photovoltaic cells, small-molecules donors/acceptor are attracting more and more attention. In this work, we investigated the electronic structures, electrochemical properties, and charge carrier transport properties of four recently-synthesized small-molecule donors/acceptor, namely, DPDCPB (A), DPDCTB (B), DTDCPB (A1), and DTDCTB (B1), by a series of ab initio calculations. The calculations look into the electronic structure of singly oxidized and reduced molecules, the first anodic and cathodic potentials, and the electrochemical gaps. Results of our calculations were in accord with those from experiments. Using Marcus theory, we also computed the reorganization energies of hole/electron hoppings, as well as hole/electron transfer integrals of multiple possible molecular dimer configurations. Our calculations indicated that the electron/hole transport properties are very sensitive to the relative separations/orientations between neighboring molecules. Due to high reorganization energies for electron hopping, the hole mobilities in the molecular crystals are at least an order of magnitude higher than the electron mobilities.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.67-68
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• 1997

1. Introduction : Gas transport through dense polymeric membranes is predominantly determined by the chain packing density as well as the chain flexibility. Thus, improved permeation properties can be obtained by controlling these two factors. In this work, the introduction of bulky substituents was attempted to improve permeation properties. Polysulfone, widely used material for gas separation membrane, was the starting material of this modification. Gas transport properties of resulting modified polysulfones were examined, and the improved properties were explained by probing the change of physical properties.

• 한국의류학회지
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• 제24권6호
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• pp.810-818
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• 2000

The purpose of this study was to analyze the effect of geometrical structure on the moisture transport properties of nonwoven batting materials. Two types of nonwovens were used such as single and double layered nonwovens. Steady and dynamic state water vapor transport properties were measured by absorption, evaporation and cobaltous chloride method respectively. The results of this study were as follows: 1) Geometrical structure affected water vapor evaporation, but there were no differences between single and double layered nonwovens in moisture absorption. Thickness and air permeability were influencing factor on water vapor transport rate. 2) Directionality of double layered nonwoven was observed both in steady and dynamic state moisture transport. There were differences between upper and lower layer of double layered nonwoven both in moisture absorption rate and color change by cobaltous chloride method. 3) In dynamic state of water vapor transport rate, single layered nonwoven reached more rapidly at the established relative humidity. It was confirmed that geometrical structure affected water vapor evaporation and hydrophilicity of fiber affected moisture absorption because there were much more water vapor transport rate by evaporation than absorption within the same period of time.

• 대한화학회지
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• 제58권5호
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• pp.500-503
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• 2014

• Macromolecular Research
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• 제12권2호
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• pp.145-155
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• 2004

Facilitated transport membranes for the separation of olefin/paraffin mixtures have long been of interest in separation membrane science because olefins, such as propylene and ethylene, which are important chemicals in petrochemical industries, are currently separated by energy-intensive cryogenic distillation processes. Recently, solid polymer electrolyte membranes containing silver ions have demonstrated remarkable performance in the separation of olefin/paraffin mixtures in the solid state and, thus, they can be considered as alternatives to cryogenic distillation. Here, we review recent progress, and critical issues affecting in the use of facilitated olefin transport membranes; in particular, we provide a general overview with reference to carrier properties, transport mechanisms, and separation performance.

• Korean Membrane Journal
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• 제5권1호
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• pp.61-67
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• 2003

Various characteristics of ion transport properties of a charged mosaic membrane with a parallel array of positive and negative functional charges were investigated, From the analysis of the volume flux, it was found that the salt flux based on nonequilibrium thermodynamics, preferential salt transport across the charged mosaic membrane. Transport properties of the magnesium sulfate(MgSO$_4$) and sucrose across the charged mosaic membrane were estimated. As a result, metal salts transport depended largely on the charged states and molecular weight otherwise nonelectrolyte solution was rejected under all experimental conditions. On the other hand, the reflection coefficient s indicated the negative value that suggested preferential material transport and was independent of charged mosaic thickness.

• Journal of Magnetics
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• 제19권2호
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• pp.140-145
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• 2014

The electrical transport properties of YBCO single layers thin film have been investigated using different physical techniques. For the purpose, the physical properties are probed numerically with help of simulation modelling. The physical transport properties were also estimated with temperature and magnetic fields limits using thermally-activated flux flow model with some modifications. The result of present simulation modelling indicated that the magnitude of activation energy depends on temperature and magnetic field. The simulations revealed thickness dependent physical transport properties including electrical and magnetic properties of deposited YBCO single layers thin films. Furthermore, it shows the temperature dependence of the pinning energy. In the nutshell, the result can be used to improve the Superconducting Properties ($T_c$) of the YBCO single layers thin films.

• 한국의류학회지
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• 제17권2호
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• pp.329-338
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• 1993

The purpose of this study was to design an instrument to simulate the Human-Clothing-Environment system and evaluate the water vapour transport properties of sweat absorbent PET fabrics. The instrument was composed of sweat generating part, clothing part which can simulate clothing layers, and enviromental part. As specimens, sweat absorbent PET, regular PET, cotton, nylon and acrylics fabrics were included. For the water vapour transport(WVT), relative humidities and temperatures were measured by film type humidity sensors and thermocouples, respectively. Water vapour pressures were calculated with measured RH's and temperatures. For the liquid water transport, wickability and demand wettability were measured. Results showed that there was a difference in terms of water vapour transport mechanism depending on the fiber type ; sweat absorbent PET showed higher WVT at the transient period then equilibrated, whereas other fabrics showed lower WVT at the transient period then increased continuously. These differences are expected to affect to the difference in the comfort properties of clothings. Sweat absorbent PET showed higher demand wettability and wickability than other fabrics. Wide application of the instrument was also suggested.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.69-73
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• 2000

We systematically analyze the influence of fracture junction, solute transfer characteristics on transport patterns in discrete, two-dimensional fracture network models. Regular lattices and random fracture networks with power-law length distributions are considered in conjunction with particle tracking methods. Solute transfer probabilities at fracture junctions are determined from analytical considerations and from simple complete mixing and streamline routing models. For regular fracture networks, mixing conditions at fracture junctions are always dominated by either complete mixing or streamline routing end member cases. Moreover bulk transport properties such as the spreading and the dilution of solute are highly sensitive to the mixing rule. However in power-law length networks there is no significant difference in bulk transport properties, as calculated by assuming either of the two extreme mixing rules. This apparent discrepancy between the effects of mixing properties at fracture junctions in regular and random fracture networks is explained by the statistics of the coordination number and of the flow conditions at fracture intersections. We suggest that the influence of mixing rules on bulk solute transport could be important in systematic orthogonal fracture networks but insignificant in random networks.