• Journal of the Korean Society for Heat Treatment
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• v.12 no.1
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• pp.31-39
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• 1999

In the present study, oxidation behavior of 304 and 316 stainless steels was investigated. After solution treatment, specimens were polished up to $1{\mu}m$ $Al_2O_3$ grade and then subjected to oxidation treatment in dry air. The range of temperature was used for oxidation treatment at $300^{\circ}C{\sim}500^{\circ}C$ and TEM was used for analyzing the components and structure of oxide film. Also, these results were compared with the results of ESCA and TG. According to the results of TEM analysis, it was found that Cr oxide film was formed on top of the surface after room temperature oxidation but amorphous Fe oxide was formed on top of the surface and polycrystalline $(Cr,Fe)_2O_3$ was formed below the amorphous Fe oxide layer after $500^{\circ}C$ oxidation treatment. The oxidized specimens at $500^{\circ}C$ showed that 316 stainless steel resists more strongly to grain and grain boundary oxidation than 304 stainless steel. These results suggested that Mo component resolved in 316 stainless steel matrix suppressed the formation of Cr carbide which may results in local Cr deplete area.

• Korean Journal of Clinical Pharmacy
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• v.6 no.2
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• pp.7-13
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• 1996

The purposes of this study were to define the pharmacokinetic parameters of vancomycin in Korean neonates, to evaluate current neonatal vancomycin dosing guideline being used in a teaching hospital, and to develop the optimal vancomycin dosing guideline. The evaluation of 35 sets of peak and trough concentrations drawn on current dosing regimen showed that $29\%$ of peak concentrations and $46\%$ of though concentrations were within therapeutic range. Otherwise, pharmacokinetic parameters, based on 62 sets of peak and trough serum concentrations obtained from 39 neonates, showed that mean vancomycin clearance (CL), volume of distribution (Vd), and terminal elimination half-life were $0.13\pm0.08\;L/hr,\;0.94\pm0.48\;L,\;and\;5.6\pm2.13$ hours, respectively. Volume of distribution (Vd) normalized for body weight remained constant throughout PCA range, whereas the absolute CL (r=0.74) and normalized CL (r=0.36) showed high correlation with PCA. Also, the normalized CL showed a strong inverse correlation (r=-0.55) with serum creatinine concentrations (SrCr). Based on the high correlation among PCA serum creatinine concentration, CL, and the daily dosage requirements, the following dosing guideline for vancomycin in neonates was suggested: 10 mg/kg $12{\sim}18$ hourly for < 30 weeks PCA and < 0.6 mg/dl SrCr; 10 mg/kg 18 hourly for < 30 weeks PCA and $0.6{\sim}1.2$ mg/dl SrCr; 10 mg/kg 8 hourly for $30\sim44$ weeks PCA and < 0.6 mg/dl SrCr; 10 mg/kg 12 hourly for $30\sim44$ weeks PCA and $0.6{\sim}1.2$ mg/dl SrCr.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.383-390
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• 2017

Heavy metal contamination of soil might be a cause of serious concern due to the potential health impacts of consuming contaminated products. In this study, the total content of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, As, and Hg) in soils was analyzed, and the difference of heavy metal contents depending on crops, soil characteristics, and topography was compared in 169 greenhouse soils obtained from Gyeongnam Province. The concentrations of the heavy metals were $0.25mg\;kg^{-1}$ (ranged 0.01~0.44) for Cd, $28.94(0.53{\sim}72.63)mg\;kg^{-1}$ for Cr, $26.03(0.5{\sim}166.13)mg\;kg^{-1}$ for Cu, $14.91(1.27{\sim}33.22)mg\;kg^{-1}$ for Ni, $15.76(0.43{\sim}57.1)mg\;kg^{-1}$ for Pb, $119.72(6.33{\sim}239.39)mg\;kg^{-1}$ for Zn, $2.54(0.01{\sim}23.57)mg\;kg^{-1}$ for As, and $0.049(0.012{\sim}0.253)mg\;kg^{-1}$ for Hg in topsoils. The concentrations of Pb and As in topsoil were highest in green pepper and those of Cd, Cr, and Ni were highest in melon. In addition, the concentrations of Cr and Ni were highest in diluvial terrace compared with the other topographies. Higher concentrations of Cd, Cr, and Ni were found in silty clay loam and silt loam soils than sandy loam and loam soils.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.713-720
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• 2002

In order to provide the basic information on the environmental pollution of Kyungsan province, the contents of Pb, Cd, Cr, Cu, Mn and Zn in soil, stream water, aquatic sediment and groundwater were investigated, and also the values of pH, COD, $KMnO_4-C$,\;NH_3-N,\;NO_2-N,\;NO_3-N$ and $Cl^-$ of stream water and groundwater were determined. The results were as follows. The values of COD, $NH_3-N,\;NO_2-N$ and $NO_3-N$ of the stream waters were very low. The contents of Pb, Cd, Cr, Cu and Zn in the stream waters were respectively at range of $0.014~0.063 mg/{\ell},\;0.004~0.007 mg/{\ell$\mid$, 0~0.045 mg/{\ell},\;0~0.008 mg/{\ell}$\;and\;$0.001~0.175 mg/{\ell}$, and these values were much lower than those of contaminated stream water in Korea. The contents of Cd, Cr, Cu and Zn in the soils were respectively at range of 0.12~O.71 ppm, 0.88~2.65 ppm, 2.86~22.33 ppm and 3.89~26.39 ppm, and these values were much lower than those of ordinary polluted areas in Korea. The contents of Cd, Cr, Cu, As, Zn and Mn in the aquatic sediments were respectively at range of 3.05~3.81 ppm, 14.6~70.6 ppm, 13.74~61.59 ppm, 76.8~465.5 ppm, 12.56~190.83 ppm and 333.3~l188.3 ppm. The values of pH, $KMnO_4-C,\;NH_3-N$, and $NO_3-N$ of the groundwaters were respectively at range of 7.6~8.4, $0~3.95{\ell}$, 0.05~0.15 mg/{\ell}$ and 0.05~0.42 $mg/{\ell}$. The contents of Pb, Cd and Cr in the groundwaters were respectively at range of 0.015~0.061 $mg/{\ell}$, 0.O06~0.009 $mg/{\ell}$ and 0.005~0.045 $mg/{\ell}$.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.289-296
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• 2000

The purpose of this study was to investigate the relationship and lipids in healthy adults on self-selected diets. These subjects consisted of 40 female college students residing in Chungnam. Anthropometric measure-ments, diet intake measurements, and blood collection were conducted. Serum concentrations of 5 microminerals(As, Cr, Mn, Se, Ni), lipids(triglyceride, total cholesterol, HDL-cholesterol), and glucose were measured by an ICP spectrometer and biochemical analyzer. The results were as follows. The mean age of the subjects was 22.34 years and the mean weight, height, and BMI were 52.89kg, 161.29cm and 20.34, respectively. The mean serum concentrations appeared to be 14.60ug/dl(As), 1.87ug/dl(Cr), 0.18ug/dl(Mn), 23.50ug/dl(Se), 0.21ug/dl(Ni), 60.73mg/dl(triglyceride), 138.49mg/dl(total cholesterol), 65.95mg/dl(HDL-cholesterol), 60.39mg/dl(LDL-cholesterol) and 88.82mg/dl(glucose). When analyzed by Pearson’s correlation coefficient, the serum concentration of Cr was negatively correlated with Ca and vitamin B12 intake(p〈0.05, p〈0.05) respectively, Mn was negatively correlated with Na intake(p〈0.05), Ni, however, was positively correlated with K intake(p〈0.05). The serum concentration of Se was positively correlated with LDL-cholesterol(p〈0.05), Ni, however, negatively correlated with total cholesterol, HDL-cholesterol, LDL-cholesterol, and glucose, respectively(p〈0.001, p〈0.01, p〈0.05). Further studies are needed to clarify the precise micromineral intakes, nutritional assessment of microminerals, and cause-effect relation of microminerals and serum lipids.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.39-47
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• 2012

Currently, most of the frequency spectrum resources are allocated and due to the lack of frequency, low frequency band, optimal for wireless communication environment is not used. Therefore, Cognitive Radio (CR) is a critical issue to solve the spectrum scarcity and to improve frequency spectrum utilization in wireless communication. In this paper, we implement data transmission and receive in a real CR system using the USRP(Universal Software Radio Peripheral) board and GNU Radio package of an open source development kit. Concretely, we detect the Primary User by spectrum sensing, and then we send Primary User information to the database. After receiving the information, because the database already sent optimal transmit power, bandwidth and channel information to CR equipment, CR can communicate without any interference to Primary User.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.37-39
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• 1991

This paper is studies the effects of additives on the magnetic properties of Sr-ferrite. The specimens have been composed of SrO and Fe$_2$O$_3$with ratio of 1:5.9. As 1st additives, it is mixed to 0.2wt%, 0.7wt% and 1wt% of CaCo$_3$with 0.3wt% SiO$_2$. As 2nd addition, it is mixed to 0.5wt%, 1wt% of Na$_2$SiO$_3$, 0.5wt%, 1wt% of Cr$_2$O$_3$and 0.5wt%, 1wt% of Al$_2$O$_3$and sintering conditions was carried out at 1210$^{\circ}C$, 1230$^{\circ}C$ and 1250$^{\circ}C$. From experiments on the magnetic properties of specimen, the results were shown follows; (1) In case of additive SiO$_2$and CaO, it is stable magnetoplumbite structure for liquid phase grown, enhances mignetic propertics. (2) In case of basic compositions + 0.5wt% Al$_2$O$_3$, it is confirmed better properties by increasing of the coercivity than 0.5wt% Cr$_2$O$_3$additives. (3) In case of mixed additives of Cr$_2$O$_3$and Al$_2$O$_3$, magnetic propeties decrease with sintering density.

• Korean Journal of Animal Reproduction
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• v.18 no.1
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• pp.7-13
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• 1994

To verify in vivo viability of IVF-derived bovine embryos, morula and blastocysts that developed from in vitro matured and fertilized ova were transferred to the uteri of recipient cows and normal calves were produced. To produce IVF-derived bovine morula or blastocysts, ova matured and fertilized in vitro were cultured in culture medium for 7~8 days at 39$^{\circ}C$ under the humicified atmosphere of 5% CO2. Two different culture systems, a co-culture system with TCM-199 and bovine epithelial cells (BOEC) and CR1aa without somatic cell support, were compared. Cleavage rates to 2~8 cell stage and developmental rates of IVF-derived bovine embryos to blastocyst stage were not different between co-culture system (51.3 and 14.0%) and CR1aa medium (60.4 and 22.1%), respectively. Embryos were classified into three grades by embryo quality and then one or two embryos in higher quality(A and B grades) were transferred to the uterus of recipients. In this study Korean Native calf was first born after transfer of IVF-derived embryos. Total four live calves were normally developed to term from IVF-derived bovine blastocysts and one female fetus was still-born approximatedly 8 months of gestation, but there was no pregnancy after transfer of morula. Therefore, normal calves could be produced after transfer of IVF-derived bovine embryos cultured in CR1aa medium without somatic cell support. In addition, our results suggest that in transfer of IVF-derived bovine embryos blastocyst stage is better than morula.

• Earthquakes and Structures
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• v.7 no.1
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• pp.39-55
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• 2014

A modified procedure is presented for assessing the seismic response of elastic non-proportionate multistory buildings. This procedure retains the simplicity of the methodology presented by the author in earlier papers, but it presents higher accuracy in buildings composed by very dissimilar types of bents. As a result, not only frequencies and peak values of base resultant forces are determined with higher accuracy, but also the location of the first mode center of rigidity (m1-CR). The closeness of m1-CR with the axis passing through the centers of floor masses (mass axis) implies a reduced rotational response and it is demonstrated that in elastic systemsa practically translational response is obtained when this point lies on the mass axis.Besides, when common types of buildings are detailed as planar structures under a code load, this response is maintained in the inelastic phase of their response as a result of the almost concurrent yielding of all the resisting bents. This property of m1-CR can be used by the practicing engineer as a guideline to form a structural configuration which will sustain minimum rotational response, simply by allocating the resisting elements in such a way that this point lies close to the mass axis. Inelastic multistory building structures, detailed as above, may be regarded as torsionally balanced multistory systems and this is demonstrated in eight story buildings, composed by dissimilar bents, under the ground motions of Kobe 1995 (component KJM000) and Friuli 1976 (component Tolmezzo E-W).

• International Commerce and Information Review
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• v.9 no.3
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• pp.273-284
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• 2007

New retailers, especially giant retailers, so called "mart" or "discounter" which introduced around 1996, when Korea's domestic retail market was opened to the world, have brought big transitions. Consequently, new comers like discounters and CVS drove out department stores, mom & pops and traditional retailers. Literatures showed two reverse opinions for the giant retailers; rising consumers' benefit, or dropping small retailers' businesses. This study have conducted to find the situation of market concentration in retail market, and to learn the new market condition in it. According to the study, in 2005, CR3's of Korea's whole retail industry was counted 12.8%, and CR5 of that was 13.9%. CR3 of discount store business was 39%, department stores' 55%, and TV home shopping businesses' was 75%. In addition to those results, indices growing worse. So, we can say this industry already get into the oligopolistic industrial organization. Generally, under monopolistic or oligopolistic market structure, consumers' benefit may shrink and businesses' surplus profit may jump. So, it means, it's good time to turn government's policy for the retail industry in Korea to fair competition policy instead of development policy.