• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.12
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• pp.578-584
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• 2005

This paper describes development of management software for transformers based on artificial intelligent analysis technology of dissolved gases in oil. Fault interpretation using the artificial intelligent analysis is performed by the artificial neural network and a rule based on the analysis of dissolved gases. The used gases are acetylene($C_{2}H_{2}$), hydrogen($H_2$), ethylene($C_{2}H_{4}$), methane($CH_4$), ethane($C_{2}H_{6}$), carbon monoxide(CO) and carbon dioxide($CO_2$). This software is mainly composed of gases input, fault's causes, expected fault's phenomena in detail, the decision on maintenance as well as report and gas trend windows. It is indicated that this is very powerful software for the efficient management of oil-immersed transformers using data analysis of gas components.

• YAKHAK HOEJI
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• v.41 no.1
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• pp.22-29
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• 1997

Poloxamer-poly (acrylic acid) (PAA) interpenetrating polymer networks (IPNs) were prepared via matrix polymerization of acrylic acid with poloxamer prepolymer. The equilibrium s welling of poloxamer/PAA IPNs was determined in various pH medium. The swelling of poloxamer/PAA IPNs was more affected by pH difference compared with the swelling of homo PAA gel due to protonation and deprotonation of the PAA network, followed by reversible formation and dissociation of the interpolymer complex due to hydrogen bonding between acidic hydrogens and ether oxygens. Nonionic/anionic/cationic drugs were incorporated into IPN matriceds as a model drug and their release behavior was studied. Nonionic, drug revealed release patterns depending solely on pH dependent swelling kinetics. In contrast, the release of ionic drugs was significantly affected by ionic drug-polymer interaction as well as the swelling kinetics.

• Journal of Soil and Groundwater Environment
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• v.17 no.1
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• pp.22-32
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• 2012

This study suggests a method to grade groundwater quality quantitatively using statistical approaches for evaluating the quality of groundwater in wells included in the Groundwater Quality Monitoring Network (GQMN). The proposed analysis method is applied to GQMN data from 2001 to 2008 for nitrate nitrogen, chloride, trichloroethylene, potential of hydrogen (pH), and electrical conductivity. The analysis results are obtained as groundwater quality grades of the groundwater representing each of the monitoring stations. The degree of groundwater contamination is analysed for water quality parameters, district, and usage. The results show that the degree of groundwater contamination is relatively high by nitrate nitrogen, bacteria and electrical conductivity and at Seoul, Incheon, Gwangju, Gyeonggido and Jeollado. The degree of contamination by nitrate nitrogen and trichloroethylene is especially high when the groundwater is used for agricultural and industrial water, respectively. It is evaluated that potable groudnwater in GQMN is significantly vulnerable to nitrate nitrogen and bacteria contamination.

• Journal of the Korean institute of surface engineering
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• v.33 no.2
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• pp.69-76
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• 2000

The rf plasma chemical vapor deposition is a common method employed for diamond or amorphous carbon deposition. Diamond possesses the strongest bonding, as exemplified by a number of unique properties-extraordinary hardness, high thermal conductivity, and a high melting tempera tore. Therefore, it is very important to investigate the synthesis of semiconducting diamond and its use as semiconductor devices. An inductively coupled rf plasma CVD system for producing amorphous carbon films were developed. Uniform temperature and concentration profiles are requisites for the deposition of high quality large-area films. The system consists of rf matching network, deposition chamber, pumping lines for gas system. Gas mixtures with methane, and hydrogen have been used and Si (100) wafers used as a substrate. Amorphous carbon films were deposited with methane concentration of 1.5% at the process pressure of S torr~20 torr, and process temperature of about $750^{\circ}C$. The nucleation and growth of the amorphous carbon films have been characterized by several methods such as SEM and XRD.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.87-90
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• 2004

This paper describes development of power transformer maintenance system using intelligent dissolved gases in oil analysis. The used gases are acetylene(C2H2), hydrogen(H2), ethylene(C2H4), methane(CH4), ethane(C2H6), carbon monoxide(CO) and carbon dioxide(CO2). The rule and neural network based gas analysis methods are used for artificial intelligent diagnosis. It is indicated that this program is efficient for diagnosis of oil immersed transformers diagnosis from application of gas analysis data of serviced transformer which has local overheating

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.100-107
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• 1999

The purpose of the study is to investigate the effect of H$_2$ pressure on partial discharge (PD) activity and aging rate in turbine generator winding insulations. A series of field tests and laboratory tests were peformed to investigate the effect of $H_2$ pressure on PD activity. Field tests were conducted at two unit turbine generators in two conditions, in $H_2$ pressure and in air atmosphere. Obtained results are as follows ; 1) ${\Delta}tan{\delta}$ and maximum partial discharge are reduced with increase of $H_2$ pressure and partial discharge inception voltage. 2) The reduction ratio of ${\Delta}tan{\delta}$ due to $H_2$ pressure is higher than one of PD magnitude. 3) Partial discharge pulses suffer from attenuation and distortion when transmitted along windings, because of the complex L-C network between windings. From the result, partial discharge pulses are subjected to resonance phenomena in a generator winding.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.220-220
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• 2006

Rheological and electrical properties of the polycarbonate (PC) / multi-walled carbon nanotube (MWNT) were studied. The MWNT was funtoinalized by treating with the hydrogen peroxide ($H_{2}O_{2}$). The electrical conductivity showed higher value for the PC/MWNT ($H_{2}O_{2}$ treated, freeze drying) composites compared that of the PC/MWNT ($H_{2}O_{2}$ treated, thermal drying) composites. From the results of the morphological, rheological, and electrical properties of the PC/MWNT composites, it is suggested that the electrical and rheological properties of the PC/MWNT composites are affected by the MWNT-MWNT network structure which is related with the MWNT morphologies such as the degree of aggregation and aspect ratio of the MWNT.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2028-2030
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• 2012

The single-crystal structure of $CaCl_2{\cdot}2C_6H_{12}O_6{\cdot}3H_2O$ was determined with Mr=525.34, a=16.054(7) ${\AA}$, b=7.864(4) ${\AA}$, c=10.909(5) ${\AA}$, ${\beta}=127.894(8)^{\circ}$, V=1086.9(9) ${\AA}^3$, C2, Z=2 and $R$=0.0227 for 1727 observed reflections. The fructose moiety of the complex exists as a ${\beta}$-D-pyranose. The calcium ion is surrounded by eight oxygen atoms, These are arranged in symmetry-related pairs derived from four sugar and two water molecules. Three nonvicinal hydroxyl groups of fructose are involved in calcium binding. All the hydroxyl groups and water molecules are involved in forming an extensive hydrogen-bond network.

• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.352-356
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• 2013

In this work, a new cadmium complex $[Cd(L)(CH_3COO)_2].2H_2O$ (1) with the ligand L, N,N'-bis(2-pyridinecarboxalidene)-1,2-cyclohexanediamine was prepared and identified by elemental analysis, FT-IR, Raman, $^1H$ NMR spectroscopy and single-crystal X-ray diffraction. The cadmium atom in the crystal structure of 1 has distorted triangular dodecahedral geometry by coordination of the four nitrogen atoms of L and four oxygen atoms of the two acetate ions. Two water molecules are also incorporated in the crystal network. The $O-H{\cdots}O$ hydrogen bonds present in the crystal structure of 1. In this work, three structural surveys including coordination numbers of the cadmium atom, coordination modes of L and resonance in pyridine-2-ylmethanimine-based compounds are presented.

• Bulletin of the Korean Chemical Society
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• v.5 no.1
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• pp.23-26
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• 1984

The crystal structure of phthalylsulfacetamide, one of the long-acting 'sulfa' drugs, has been determined by the X-ray diffraction methods. The crystal is monoclinic with cell dimensions of a = 7.980(3), b = 12.784(2), c = 18.064(7) ${\AA}$ and ${\beta}$= $112.94(2)^{\circ}$, space group $P2_1$/c and Z = 4. The structure was solved by the direct methods and refined to R = 0.048. The sulfonylacetamide moiety is folded with respect to the central phenyl ring and the benzamide and benzoyl planes are nearly perpendicular to each other. This conformation is consistent with those of the relevant molecules containing the corresponding moieties. All of the molecules in the crystal lattice are connected by a three-dimensional hydrogen bonding network.