• Journal of Energy Engineering
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• v.1 no.1
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• pp.97-101
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• 1992

A mathematical model has been developed for an analytical calculation of distribution coefficient (K$_1$) in the presence of a chelating agent, The newley formulated K$\_$D/ is given as a function of the mole fraction of a free metal ion in the solution, ${\beta}$, and will serve as an alternative for the tedious individual measurements of K$\_$D/. This formulation will be used to analyze the effects of the presence of chelating agents on the adsorption capacity of geologic media such as clay minerals and soils. The present method may be a significant progess for the evaluation of the transport phenomena and separation processes of metal ions (or radionuclides) in the presence of chelating agents.

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.292-300
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• 1996

The scattering of incident ions and target atoms in the amorphous solid matters are calculated by Monte Carlo simulation method. The experimentally derived universal scattering cross-section of Kalbitzer and Oetzmann is used to describe nuclear scattering. For electronic energy loss, the Lindhard-Scharff and Bethe formula are used. Comparing the ion scattering formulas and ranges with the known results of experiment and other programs, we find our results are good agreement with others.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.187-195
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• 2003

The present article is concerned with the overview of carbonaceous materials used as anode materials for lithium ion secondary batteries. This article first classified carbonaceous materials into graphite, soft carbon and hard carbon according to their crystal structures, and then summarised the previous works on the characteristics of lithium intercalation/deintercalation into/from the carbonaceous materials. Finally this article reviewed our recent research works on the mechanism of lithium transport through graphite, soft carbon and hard carbon electrodes from the kinetic view point by the analysis of the theoretical and experimental potentiostatic current transients.

• Journal of the Korean Society of Safety
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• v.23 no.5
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• pp.49-53
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• 2008

Glow discharge has lots of attractive properties, such as lower discharge sustaining voltage, no generation of ozone, and so on. And more, ionizer was developed recently using an atmospheric pressure glow discharge. On the other hand, ionizer needs a compressed or blown air to transport ion for charged objects. This air is very useful in explosive hazardous area to prevent the explosion of flammable gas and/or vapor by ignition sources, e.g. electrical spark. In this paper, we investigated the ionizing characteristic of atmospheric pressure glow discharge by controlled air flow rate from 5 liters to 60 liters a minute, and compared with decay time between the corona discharge and glow discharge as a function of some direction and distance from discharge ion source. We confirmed that an air flow rate needs 25 liters a minute to sustain the most suitable atmospheric pressure glow discharge and to increase an ionizing efficiency.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.94-100
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• 2013

The elements B, P and As can each be implanted in silicon; for the fabrication of integrated semiconductor devices and the wells in CMOS (complementary metal oxide semiconductor). The implanted range due to different implanted species calculated using TRIM (Transport of Ions in Matter) simulation results was considered. The profiles of implanted samples could be measured using SIMS (secondary ion mass spectrometry). In the comparison between the measured and simulated data, some deviations were shown in the profiles of MeV implanted silicon. The Moliere, C-Kr, and ZBL potentials were used for the range calculations, and the results showed almost no change in the MeV energy region. However, the calculations showed remarkably improved results through the modification of the electronic stopping power. The results also matched very well with SIMS data. The calculated tolerances of $R_p$ and ${\Delta}R_p$ between the modified $S_e$ of TRIM and SIMS data were remarkably better than the tolerances between the TRIM and SIMS data.

• Journal of the Korean Vacuum Society
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• v.4 no.3
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• pp.334-341
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• 1995

IB-AI-VIB2 및 IB-AI-VIB2 :Co2+ 결정을 고순도 원소를 출발 물질로 하고 iodine을 수송 매체로 사용하여 chemical transport reaction method로 성장시켰다. 성장된 결정의 결정구조는 chalcopyrite 구조였으며, energy gap은 direct band gap으로 3.514~1.814 eV 정도로 주어졌으며, cobalt를 불순물로 첨가할 때 energy gap은 감소하였다. IB-AI-VIB2 :Co2+ 결정에서 첨가된 cobalt가 모체결정의 Td symmetry site에 Co2+ ion으로 위치하여, Co2+ ion의 energy 준위 사이의 전자전이에 기인하는 불순물 광흡수 peaks가 나타났다. 이 불순물 광흡수 peaks에 결정장 이론을 적용하여 구산 1st-order spin-orbit coupling parameter(λ)는 -183~ -189cm-1정도였고, 2nd-order spin-orbit coupling parameter(P)는 225~239 cm-1정도였으며, crystal field parameter(Dq)는 328~395cm-1, Racah parameter(B)는 531~552cm-1정도였다.

• Journal of the Korean Society of Visualization
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• v.6 no.1
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• pp.3-16
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• 2008

Controlling fluid flows in micro scales is a non-trivial issue among those who are involved in designing lab-on-chips. Pumping and mixing by using electrokinetic principles has been popular in that the method requires a few parts and it is easy to control. This paper explains the basic mechanism of the electroosmotic flows caused by AC together with presenting some numerical results. In particular, the fundamental, physical idea involved in the mechanism will be illustrated in terms of the kinematic aspect. Since the electroosmotic flows are mainly driven by the motion of ions, we also demonstrate the ion motions by using the numerical-visualization method.

• Journal of Biomedical Engineering Research
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• v.8 no.2
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• pp.123-134
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• 1987

The transport phenomena of alkali metal chlorides through poly(2 hydroxyethyl methacrylate) hydrogel membrane have been studied using electrodialysis. The hydrogel membranes were prepared by the polymerization of 2-hydroxvethyl methacrylate in the presence of 45%(V/V) H2O and ethyleneglycodimethacrylate. The initiator used in the polymerization was azobismethylisobutyrate (AMIB) prepared from azobisiobtyronitrile (AIBN) using Mortimer method. The permeability of alkali metal chlorides such LiCl, NaCl and KCI at 50 voltage was obtained. The permeability of NaCl was also observed at 30, 40, 50, and 60 voltages respectively. The concentration of solutes permeated through the membrane was measurer by flame photometry. The experimental results have been discussed with the comparison of apparent solute molecular size, the self-diffusion coefficient of solutes, the transport number of cations in aqueous solution. These indic aloes that poly(2 hydroxyethyl methacrylate) hydrogel membrane shows a specific selectivity for sodium ion.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.3-17
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• 2007

This paper provides an introduction to life-span simulation and numerical approach to support the performance design processes of reinforced concrete structures. An integrated computational system is proposed for life-span simulation of reinforced concrete. Conservation of moisture, carbon dioxide, oxygen, chloride, calcium and momentum is solved with hydration, carbonation, corrosion, ion dissolution. damage evolution and their thermodynamic/mechanical equilibrium. Coupled analysis of mass transport and damage mechanics associated with steel corrosion is presented for structural performance assessment of reinforced concrete. Multi-scale modeling of micro-pore formation and transport phenomena of moisture and ions are mutually linked for predicting the corrosion of reinforcement and volumetric changes. The interaction of crack propagation with corroded gel migration can also be simulated. Two finite element codes. multi-chemo physical simulation code (DuCOM) and nonlinear dynamic code of structural reinforced concrete (COM3) were combined together to form the integrated simulation system. This computational system was verified by the laboratory scale and large scale experiments of damaged reinforced concrete members under static loads, and has been applied to safety and serviceability assessment of existing structures. Based on the damage details predicted by the nonlinear finite element analytical system, the life-span-cost of RC structures including the original construction costs and the repairing costs for possible damage during the service life can be evaluated for design purpose.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.13-37
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• 2010

The performance of an electrodialyzer for concentrating seawater is predicted by means of a computer simulation, which includes the following five steps; Step 1 mass transport; Step 2 current density distribution; Step 3 cell voltage; Step 4 NaCl concentration in a concentrated solution and energy consumption; Step 5 limiting current density. The program is developed on the basis of the following assumption; (1) Solution leakage and electric current leakage in an electrodialyzer are negligible. (2) Direct current electric resistance of a membrane includes the electric resistance of a boundary layer formed on the desalting surface of the membrane due to concentration polarization. (3) Frequency distribution of solution velocity ratio in desalting cells is equated by the normal distribution. (4) Current density i at x distant from the inlets of desalting cells is approximated by the quadratic equation. (5) Voltage difference between the electrodes at the entrance of desalting cells is equal to the value at the exits. (6) Limiting current density of an electrodialyzer is defined as average current density applied to an electrodialyzer when current density reaches the limit of an ion exchange membrane at the outlet of a desalting cell in which linear velocity and electrolyte concentration are the least. (7) Concentrated solutions are extracted from concentrating cells to the outside of the process. The validity of the computer simulation model is demonstrated by comparing the computed results with the performance of electrodialyzers operating in salt-manufacturing plants. The model makes it possible to discuss optimum specifications and operating conditions of a practical-scale electrodialyzer.