• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.7
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• pp.708-712
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• 2004

Shallow $p^+-n$ junctions were formed by ion implantation and dual-step annealing processes. The dopant implantation was performed into the crystalline substrates using BF$_2$ ions. The annealing was performed with a rapid thermal processor and a furnace. FA+RTA annealing sequence exhibited better junction characteristics than RTA+FA thermal cycle from the viewpoint of junction depth and sheet resistance. A new simulator is designed to model boron diffusion in silicon. The model which is used in this simulator takes into account nonequilibrium diffusion, reactions of point defects, and defect-dopant pairs considering their charge states, and the dopant inactivation by introducing a boron clustering reaction. Using initial conditions and boundary conditions, coupled diffusion equations are solved successfully. The simulator reproduced experimental data successfully.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.263-270
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• 2020

In this study, the physical mechanism and diffusion effects in aluminium implanted silicon was investigated. For fabricating power semiconductor devices, an aluminum implantation can be used as an emitter and a long drift region in a power diode, transistor, and thyristor. Thermal treatment with O₂ gas exhibited to a remarkably deeper profile than inert gas with N₂ in the depth of junction structure. The redistribution of aluminum implanted through via thermal annealing exhibited oxidation-enhanced diffusion in comparison with inert gas atmosphere. To investigate doping distribution for implantation and diffusion experiments, spreading resistance and secondary ion mass spectrometer tools were used for the measurements. For the deep-junction structure of these experiments, aluminum implantation and diffusion exhibited a junction depth around 20 ㎛ for the fabrication of power silicon devices.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.05a
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• pp.126-128
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• 2002

• Proceedings of the Korean Vacuum Society Conference
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• 1993.02a
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• pp.6-6
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• 1993

With brief instroduction of fabrication methods of dia.ond fillls by plasma CVD, recent progress in diamond research mainly done in the author's laboratory at Osaka University is reviewed.especially on the following topics: "low temperature diallond fabrication", "ion implantation", "hydrogen plasma treatment of ion-implanted diaaond to remove ion-induced damage", "Oxygen diffusion into the bulk assisted by the hydrogen treatllent", and "hole-burning effect".ffect".

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.227-228
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• 2017

In this paper, electrolytic behavior of Cerium and Ce-Bi ion system was studied. The electrochemical behavior of Ce was studied in $LiCl-KCl-CeCl_3$ molten salts using electrochemical techniques Cyclic Voltammetry on tungsten electrodes at 773K. During the process of CV electrolysis, intermetallic compound were observed of Ce, Cex-Biy. Further study, in order to determine clarity of diffusion coefficient in this experiment, we will compare result of electrochemistry method and we also need to quantitative research.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.593-597
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• 2016

The effects of relative humidity, current density and temperature on the ionic conductivity were studied in PEMFC (Proton Exchange Membrane Fuel Cell). Water contents and water flux in the electrolyte membrane largely affected ion conductivity. The water flux was modelled and simulated by only electro-osmotic drag and back-diffusion of water. Ion conductivities were measured at membrane state out of cell and measured at MEA (Membrane and Electrode Assembly) state in condition of operation. The water contents in membrane increase as relative humidity increased in PEMFC, as a results of which ion conductivity increased. Current enhanced electro-osmotic drag and back diffusion and then water contents linearly increased. Enhancement of current density results in ion conductivity. Ion conductivity of about 40% increased as the temperature increased from $50^{\circ}C$ to $80^{\circ}C$.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.75-80
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• 1998

Ammonium ion is notorious for the adverse effects upon many of the important uses of water such as toxcity to fish, corrosion of metals and concrete, and concern over man's consumption. A clinoptilolite, which is a naturally occurring zeolite selective for ammonium ion exchange, has been used. Batch isotherm experiments were conducted for measuring ammonium ion exchange capacity. The ion exchange capacity was well described either by the Langmuir equation or by the Freundlich equation. As the particle size of the clinoptilolite decreased, exchange capacity was increased. The smaller particle size enhaced the exchange of ammonium ion due to the greater surface area and decreased diffusion to the exchange sites within the zeolite. Ammonium ion exchange capacity tended to decrease when the temperature increased from $20^{\circ}C$ to $35^{\circ}C$, and the temperature correction factor was found to be 0.98 in the Langmuir equation.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.429-432
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• 2000

The studies on chloride diffusion of concrete have been done so far by many researchers. However, there are few studies on the effects of other attacks, like carbonation, on chloride diffusion properties. In this study, the experiments are carried out focusing on this by varying cement type, water to cement ratio and replacement of fly ash of concrete. The results show that carbonation attacks do not affect greatly chloride diffusion properties of plain concrete, while the different tendencies are exhibited for fly ash concrete. Therefore, it is desirable to consider the effects of carbonation attacks on the chloride diffusion model to predict accurately the penetration of chloride ion fly ash is partially replaced for cement.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.157-163
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• 2006

A new technique utilizing LII signal for the measurement of flow velocities of laminar diffusion flames has been investigated. Soot particles in ethylene diffusion flames are heated by a modulated Ar-ion laser beam. LII signals and their phase angles are measured using a lock-in amplifier at the different flame heights and the axial flow velocity are obtained from the measured phase angle delay. The measured velocities are similar to those from LDV measurements under the same operating conditions. The effects of laser power, LII signal wavelength, and modulation frequency are not sensitive to the velocity measurement. However, the choice of an optical chopper blade type could affect the measurement result. The use of a 6/5 chopper blade showed the better result that is possibly due to the square shape of modulated laser beam. This study successfully demonstrated that axial flow velocities of laminar diffusion flames can be measured by a new technique utilizing LII signal, which does not need particle seeding unlikely to LDV or PIV techniques.

• Journal of the Korean Ceramic Society
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• v.36 no.5
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• pp.490-496
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• 1999

The sintering behavior of LTCC (low temperature cofired ceramics) chip couplers was investigated in relation with Ag diffusion at the interface of glass ceramic substrate-Ag electrode. Sintering temperature was in the range of 825$^{\circ}C$-975$^{\circ}C$. The commercial green sheet and silver electrode were used. Below 875$^{\circ}C$ the diffusion of the Ag ion into the substrate and the penetration of glassy phases into the electrode occurred due to an increase of fluidity. Thus the lectrode line was severely deformed and damaged. At 975$^{\circ}C$ the transformation of crystalline phases into glassy phases and the melting of the Ag electrode resulted in the diffusion of the considerable amount of Ag ions.