경주산 규조토를 이용한 비실리카겔 흡습제에 관한 연구

서숭혁,이해룡 啓明大學校 産業技術硏究所 1993 産業技術硏究所 論文報告集 Vol.16 No.2

The water-vapor adsorption capacities of desiccants were investigated over a wide range of pre-calcined temperatures, screened particle-sizes, and relative humidities. Natural porous diatomites, currently produced in Kyungju, Kyungpook area, were used as moisture sorbents. Under all relative humidities conditions employed in this work, the moisture adsorption capacities of diatomite desiccants were shown to be better than those obtained from silica-gel desiccants. The silica-gel desiccants arrived at saturated equilibrium in relatively short time less than 10 hours, while the diatomite desiccants exhibited the continous moisture adsorption even after 40 hours due to the capillary condensation effects. The amount of adsorbed moistures were increased with increasing pre-calcined temperature up to 800˚C. Above this temperature, however, the structural change to cristobalite phase significantly led to the decrement of adsorption rate.

Vectorization and Optimization of Molecular Dynamics Programs Using the Cray-2 Supercomputer

徐崇爀 계명대학교 산업기술연구소 1992 産業技術硏究所 論文報告集 Vol.15 No.2

The highly optimized and vectorized algorithm for molecular dynamics simulations recently proposed by Brode and Ahlrichs is applied to the systems interacting though the Lennard-Jones 12-6 pair potential. The Cray-2 vectorized version is shown to be efficient for the small system of less than 1,000 particles. For example, 45% reduction of the total CPU time is achieved for the system of 108 particles and 10% for 864 particles, respectively, by comparing with those obtained from the conventional vectorized codes on the same computer.

Li-X형 제올라이트에 흡착된 기체 분자의 Monte Carlo 전산 모사 연구

서숭혁,이윤태 啓明大學校 産業技術硏究所 1996 産業技術硏究所 論文報告集 Vol.19 No.1

In this paper, grand canonical ensemble Monte Carlo simulation have been carried out to investigate the adsorption and structural properties of nitrogen and oxygen molecule adsorbed in Li-X zeolite systems. The adsorption isotherm, energy distribution curves and mass density profiles are computed over a wide range of temperatures and bulk pressures. For bulk pressure conditions employed in this work, the adsorption capabilities of nitrogen is consistently greater than those of oxygen mainly due to the larger quadrupole moment on nitrogen interacted with lithium cations. Nitrogen molecules display considerable localization near the adsorption sites of lithium cations, while oxygen molecules diffuse throughout zeolite cavities. Separation factors are also calculated for the mixture compositions of N₂/O₂and the resulting values in the range 6 to 14 are found to be higher comparing with 3.0 to 3.5 for the systems of zeolite 5A or 13X.

분자 전산 모사의 van der Waals 인력 포텐셜

서숭혁 啓明大學校 産業技術硏究所 1996 産業技術硏究所 論文報告集 Vol.19 No.1

In this paper, we have shown that commonly used Lennard-Jones and Exp-6 potentials in molecular simulations failed to account for the high quality rare-gas data. It was found that a relatively simple potential based on the distance-buffered interaction accurately reproduced the rate-gas potentials over the wide range of interatomic separations. For the unlike pair potentials, the standard arithmetic and geometric mean combination rules performed poorly, and the alternative combination rule performed significantly via the cubic mean and HHG approximation for minimum energy separation R*ij and well depth ξij.

일차원적 연결 구형 세공에 관한 분자 전산 모사

서숭혁 啓明大學校 産業技術硏究所 1997 産業技術硏究所 論文報告集 Vol.20 No.-

Molecular dynamics simulations have been carried out to investigate the Knudsen diffusion properties for the non-adsorbed, collisionless molecules confined within the one-dimensional model pore system, namely, the sequentially linked spherical pore. Simulation results were used to evaluate various theoretical calculations appeared in the literature including the random walk approximation, the radiating disc method, and the molecular path tracing method. A latter theory, in comparison with simulation results, has proven to be successful to qualitatively and quantitatively predict the diffusion coefficient in the Knudsen regime over the entire ranges of the pore cross-sectional variations in such a model system.

분무형 표면 보호 피막제 특성 연구

이해룡,서숭혁 啓明大學校 産業技術硏究所 1998 産業技術硏究所 論文報告集 Vol.21 No.2

The spray-type protective coating film has been developed and applied for alumina, glass, wooden, and metal structures to extend the protection against the elements that cause structural corrosion and degradation. We describe the characteristics of selecting and testing additives as well as sensitivities to variations in selecting the start formulation. The product formulation is obtained by blending the theoretical together with the practical in solvent-based applications. From a commercial view point, this durable film method can effectively provide the first line of defense for complex structural shape as a barrier to the effects of water, oxygen, pollutants and microorganisms.

Solvation Pressure of Simple Fluids in Spherical Pores

Soong Hyuck Suh 한국화학공학회 1996 화학공업과 기술 Vol.14 No.1

N/A Computer simulations via the grand canonical ensemble Monte Carlo method been been carried out W investigate the equilibrium properties of simple fluids distributed between the external hulk phase and the pore phase. Salvation pressures and pore density profile, are computed for the system of hard-sphere fluids incide a spherical hard-wall nudel pore. For dilute concentrations, the resulting salvation pressures are approximately equal to those in the bulk phase. However, at a moderately dense concentration of n(L4) a weakly oscillatory behavior of the solvation pressure starts to emerge. the apparent maximum and minimum peaks are exhibited in the case of n_β-0.6 due to the local densiy inhmxtgeneities in the pore phase.

Graphite상 Lennard-Jones유체의 흡착 인력 에너지

Suh,Soong-Hyuck 계명대학교 산업기술연구소 1993 産業技術硏究所 論文報告集 Vol.16 No.1

An analytic expression for gas/surface interactions was developed and applied for the systems of Lennard-Jones fluids adsorbed in the graphite basal plane. The summed 10-4 power potentials, which are derivable from the model that represents the total as a pairwise sum between gas-atom and solid-atom energies, are proven to be more realistic representations of model interactions than those obtained from the structureless 0-3 power potentials.

A LONG - RANGED ELECTROSTATIC INTERACTION IN COMPUTER SIMULATIONS

Suh, Soong Hyuck,Ha, Ki Ryong,Kim, Jong Shik,Park, Chan Young,Heo, Nam Ho 한국화학공학회 1992 Korean Journal of Chemical Engineering Vol.9 No.3

Molecular dynamics simulations for the primitive model systems of 1-1 and 2-2 electrolyte solutions were carried out to investigate the influence of system size and long-ranged potentials. Both the nearest image convention and the Ewald summation method were employed to handle the effective electrostatic interactions. For the thermodynamic and structural properties of such systems, the resulting calculations obtained from both two methods do not show any measurable inaccuracy except for the system of 2-2 electrolytes at M_t=6.0. However, the nearest image results indicate lower self-diffusion coefficients compared with those given by the Ewald method. In this case, the time-dependent dynamic properties are shown to be sensitive to the treatment of long-ranged Coulombic interactions.

The Oscillation of Solvation Force in Cylindrical Micropores

SUH,Soong-Hyuck 啓明大學校 産業技術硏究所 1992 産業技術硏究所 論文報告集 Vol.15 No.1

Grand canonical ensemble Monte Carlo simulations for hard-sphere fluids and fluid mixtures confined within cylindrical micropores have been carried out for a wide range of pore size. The simulation results obtained have indicated that the partitioning and solvation force of solutions containing macromolecules of different size are subject to a selection process, In addition the non-continuum selectivity is also shown to be sensitive to the size of the macromolecules and dramatically increases as the macromolecules approach the size of the pore.