• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.335-344
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• 2006

In this paper a computer program was developed, which simulates the Li reduction process of PWR spent fuel, and the amount of a produced metal or chloride compound was calculated at the various amount of Li with the program. It establishes a database, which is composed of some characteristics related to a chemical reaction equation and thermodynamic data, and it calculates the transformed rate of PWR spent fuel oxide at the certain amount of Li by using the database as input data. As the results of the performance test of the program, it was validated that the transformed values of oxides, except for $Eu_2O_3$ and $Sm_2O_3$, were almost the same to within about a 6 % error with those calculated by the previous code and that the calculated amount of Li was also exactly consistent with the theoretical one, which is used for a complete reaction of each oxide in a single chemical reaction. A relationship between Li and the transformed metal of each oxide was analyzed on the basis of the quantities calculated with the verified development program. Of the results, when the amount of Li was given to be 250 mole, the 83.73 percentage of $UO_2$ was transformed into U while the remainder was still to be $UO_2$. In addition, it was appeared that the 297 mole of Li was needed to completely convert $UO_2$ into U.

• Economic and Environmental Geology
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• v.25 no.1
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• pp.27-39
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• 1992

Several pyrophyllite deposits occur around the Milyang area where Cretaceous andesitic rocks and spatially related granitic rocks are widely distributed. Pyrophyllite ores consist mainly of pyrophyllite, and quartz with small amount of sericite, pyrite, dumortierite, and diaspore. The andesitic rocks and spatially related granitic rocks in this area suggest that they could be formed from the same series of a calc-alkaline magma series. The contents of $SiO_2$, $Al_2O_3$, LOI(loss on ignition) are enriched, and $K_2O$, $Na_2O$, CaO, MgO, $Fe_2O_3$ are depleted in altered andesitic rocks and ores. Enrichment of As, Cr, Sr, V, Sb and depletion of Ba, Cs, Ni, Rb, U, Y, Co, Sc, Zn are characteristic during mineralization. The pyrophyllite ores can be discriminated from the altered-and unaltered wall-rocks by an increasing of $(La/Lu)_{cn}$ from 4.18~22.13 to 8.98~55.05. In R-mode cluster analysis, Yb-Lu-Y, La-Ce-Hf-Th-U-Zr, $TiO_2-V-Al_2O_3$, Sm-Eu, $CaO-Na_2O-MnO$, Cu-Zn-Ag, $K_2O-Rb$ are closely correlated. In the discriminant analysis of multi-element data, $P_2O_5$, As, Cr and $Fe_2O_3$, Sr are helpful to identify the ores from the unaltered-and altered wall-rocks. In the factor analysis, the factors of alteration of andesitic rocks and ore mineralization were extracted. In the change of ions per unit volume, $SiO_2$, $Al^{3+}$ and LOI are enriched and $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Mn^{2+}$ and $Fe^{3+}$ are depleted during the alteration processes. The Milyang and the Sungjin pyrophyllite deposits could be mineralized by hydrothermal alteration in a geochemical condition of low activity ratio of alkaline ions to hydrogen ion with reference to spatially related granitic rocks.

• Journal of the Korean Ceramic Society
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• v.29 no.11
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• pp.888-892
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• 1992

The chemically induced grain-boundary migration has been studied in MgAl2O4 spinel under ZnO atmosphere. MgAl2O4 compacts been prepared by sintering powder mixture of Al2O3 and MgO at 1$600^{\circ}C$ for 60 h in air. The sintered MgAl2O4 has been heat-treated at 150$0^{\circ}C$ in a ZnO atmosphere. During the heat-treatment grain boundaries have become curved or faceted, and the total area of grain boundaries have increased. In the migrated region, the ZnO content is higher by 6 wt% than that in other regions, indicating that the migration was induced by addition of ZnO. In some shrinking grains, the faceted planes of different grain boundaries for the same grain are parallel to each other. This result provide an experimental support for the coherency strain energy in diffusion layer of the shrinking grain as being the major driving force. Calculated coherency strain energy of MgAl2O4 shows the maximum at {111} planes and the minimum at {100} planes. Although the minimum surface energy is at {111} planes, the faceted moving boundaries are expected to be {100} planes because of lowest driving force for the grain-boundary migration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.418-419
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• 2006

We investigate the influence of the ambient gas during thermal annealing on the photoluminescence (PL) properties of europium-silicate thin films. The films were fabricated on substrates by using a radio-frequency magnetron sputtering method and subsequent rapid thermal annealing (RTA). The mechanism for the formation of the europium silicates during the annealing process was investigated by using X-ray diffraction (XRD) spectroscopy, Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). A series of narrow PL spectra from $Eu^{3+}$ ions was observed from the film annealed in $O_2$ ambient. Broad PL spectra associated with $Eu^{2+}$ ions, with a maximum intensity at 600 nm and a FWHM of 110 nm, were observed from the thin film annealed at $1000^{\circ}C$ in $N_2$ ambient.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.85-89
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• 1999

FDE panel was successfully fabricated through the integration of a 0.7" diagonal Si-based Mo-tip FEA with 25${\times}$25 pixels, Y2O3:Eu or ZnO:Zn phosphor screen, and vacuum sealing through an exhausting glass tube, including a getter. The panel system was driven by an external driver circuit having pulse width modulation(PWM) driving scheme. Before character imaging, it was stabilized through tip aging by slowly increasing a pulse-mode emission current and phosphor aging by a coulombic charging process. After aging, luminescent characteristics such as emission uniformity, charging and arcing phenomena were shown to be improved significantly.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.3
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• pp.127-132
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• 2010

Reactive oxygen species (ROS), which include hydrogen peroxide ($H_2O_2$), the superoxide anion (${O_2}^-{\cdot}$), and the hydroxyl radical ($OH{\cdot}$), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of $H_2O_2$ on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at -60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM $H_2O_2$ gradually potentiated mIPSCs. This potentiating effect of $H_2O_2$ was blocked by the pretreatment with either 10,000-unit/mL catalase or $300-{\mu}M$ N-acetyl-cysteine. The potentiating effect of $H_2O_2$ was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N -(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.124-129
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• 2016

Endotoxin, also known as lipopolysaccharide (LPS) produced by the cell wall of gram negative bacteria can be present in any liquid or on any biomaterial. Endotoxin in blood can cause fever and inflammation. In this study, we compared bacterial endotoxin using Escherichia coli O157:H7, Klebsiella oxytoca, Salmonella Typhi, Shigella sonnei and Morganella morganii. Bacteria were cultured for use in the experiment, and diluted to $1.5{\times}10^8CFU/mL$. A check marked sensitivity confirmatory test of the Limulus amebocyte lysate (LAL) reagent was performed to examine the validity. The end point reaction to each bacteria sample was confirmed with 10 fold dilution and then the final reaction end point was confirmed by 2 fold dilution between the dilution step and the upper dilution step. According to the results, in detection of endotoxins in more than 0.015 EU/mL, E. coli O157 was 75~37.5 CFU/mL, K. oxytoca 37.5~18.75 CFU/mL, M. morganii and S. Typhi 3.75~1.875 CFU/mL, and S. sonnei 7.5~3.75 CFU/mL. The resulting value was finally ensured by a confirmation test for the inhibitory factor. Based on this study, conduct of further research on bacterial endotoxin is encouraged.

• Journal of Plant Biotechnology
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• v.5 no.2
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• pp.131-135
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• 2003

Callus and cell suspension cultures of Eurycoma longifolia Jack were initiated from leaves of different trees. The leaf explant of tree Eu9 produced the most calli and also induced high cell biomass in the cell suspension culture. Optimum production of cell biomass could be initiated in proliferating culture medium with a pH of 5.75 prior to autoclaving. The effects of macronutrient inorganic salts of Murashige and Skoog (MS) liquid medium supplemented with X on production of cell biomass of Eurycoma longifolia were also investigated. The highest cell biomass was produced in MS medium containing macronutrients of $21\;mM\;NH_4NO_3,\;12.25\;mM\;KNO_3,\;3.00\;mM\;CaCl_2.2H_2O,\;0.575\;mM\;MgSO_4.7H_2O$, and $1.83\;mM\;KH_2PO_4$. A new medium labeled as TAM was formulated for the production of Eurycoma longifolia cell biomass in the cell suspension culture.

• Macromolecular Research
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• v.17 no.3
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• pp.174-180
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• 2009

Chemical modification of titanium/titanium oxide (Ti/$TiO_2$) substrates has recently gained a great deal of attention because of the applications of Ti/$TiO_2$-based materials to biomedical areas. The reported modification methods generally involve passive coating of Ti/$TiO_2$ substrates with protein-resistant materials, and poly(ethylene glycol) (PEG) has proven advantageous for bestowing a nonbiofouling property on the surface of Ti/$TiO_2$. However, the wider applications of Ti/$TiO_2$ based materials to biomedical areas will require the introduction of biologically active moieties onto Ti/$TiO_2$, in addition to nonbiofouling property. In this work, we therefore utilized surface-initiated polymerization to coat the Ti/$TiO_2$ substrates with polymers presenting the nonbiofouling PEG moiety and subsequently conjugated biologically active compounds to the PEG-presenting, polymeric films. Specifically, a Ti/$TiO_2$ surface was chemically modified to present an initiator for atom transfer radical polymerization, and poly(ethylene glycol) methacrylate (pEGMA) was polymerized from the surface. After activation of hydroxyl groups of poly(pEGMA) (pPEGMA) with N,N'-disuccinimidyl carbonate, biotin, a model compound, was conjugated to the pPEGMA films. The reactions were confirmed by infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle goniometry, and ellipsometry. The biospecific binding of target proteins was also utilized to generate micropatterns of proteins on the Ti/$TiO_2$ surface.

• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.149-165
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• 1996

In order to get some basic datas on environmental friendly funtion against soil and water pollution and safe vegetable production by organic farming, chemical characteristics of soils cultivated by the conventional farming, greengouse cultivation and organic farming and acumulation of NO3--N in chinese cabbage and lettuce were analysed. The highest value of NO3--N in 0-30cm subsoil of organic farming was found among the 3 different farming systems, and it was 3.6 and 6.6 times higher than those of conventional farming in chinese cabbage and lettuce respectively. P2O5 also show high accumulation in the rhizosphere of organic farming compared to convnetional farming. The accumulation of NO3--N and P2O5 in the rhizosphere of organic farming were simial to those of greenhouse cultivation. The NO3- accumulation in chinese cabbage and lettuce by organic farming reach 3224ppm in chinese cabbage and 2543ppm in lettuce and it were 4.7 and 6.4 times higher than those of convnetional farming. It is urgently necessary to introduce the basic standard of IFOAM, EU and FAO/WHO Codex on organic agriculture into korean organic agriculture for operation of environmental friendly system and production of safe vegetable in terms of NO3-.