• Journal of Environmental Health Sciences
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• v.26 no.2
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• pp.22-29
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• 2000

This study was performed to investigate the concentrations of TSP, PM10 and heavy metals(Pb, Cd,Hg, Ni, Zn) of underground parking lots in Taegu city. The samples were collected from 3 department stores and 1 central park in the winter and the summer, 1997. The samples of 3 department stores were divided into sale period and non-sale period in the winter and the summer. The concentrations of TSP and PM10 were 109.6±1.5㎍/㎥ and 93.3±1.5㎍/㎥. In TSP, the zinc was the highest level, 287.16±1.5ng/㎥ and the cadmium was the lowest, 2.4±2.1ng/㎥ and in PM10, the zinc was the highest level, 193.6±1.5ng/㎥ and the cadmium was the lowest, 0.6±3.9ng/㎥. The correlation coefficient between the concentration of TSP and PM10 was 0.982(p<0.05). The correlation coefficients of corresponding heavy metal in TSP and PM10 were 0.863 for lead, 0.617 for mercury, 0.890 for nickel and 0.850 for zinc(p<0.05). The concentrations of TSP, PM10 and cadmium of PM10 in the winter were higher than those of the summer. However, the concentration of Hg of PM10 in the summer was higher than that of the winter. The concentrations of TSP and PM10 in sale period was higher than those of non-sale period and the concentrations of heavy metal in TSP and PM10 were not significantly different between sale and non-sale period. The proportions of PM10 to TSP were above 60% in dust, lead, nickel, and zinc and less than 40% in cadmium and mercury. The concentrations of TSP, PM10 and heavy metal in the underground parking lots were comparatively lower than those of general atmosphere. However, this kind of research to PM10 in the underground parking lots must be continued because it is very important particulate matter that affects human beng's health.

• Journal of Nutrition and Health
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• v.28 no.7
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• pp.620-628
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• 1995

This study investigated micro-mineral content in human milk along with nutritional intake of lactating women. Milk samples were collected from 33 healthy lactating women and mineral levels were analyzed. Copper, zinc, manganese and selenium were analyzed. The factors that affect the mineral levels in human milk were also investigated longitudinally from 2-5 days to 12 weeks postpartum. Concentrations of manganese and selenium didn't differ significantly within the lactation period. the levels of copper and zinc declined linearly over the first 12 weeks of lactation. Statistically significant quadratic trends were observed in zinc concentrations. There was no significant correlation between maternal age and mineral concentrations throughout the lactation period. In addition, no significant differences were found between the primipara and the multipara for mineral concentrations in human milk.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.2
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• pp.137-142
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• 1991

A method is developed for the simultaneous determination of dissolved iron, copper, and zinc in rainwater. The method involves 25-fold evaporative concentration, ion chromatographic separation and subsequent spectrophotometric detection after post-column reaction with 4-(2-pyridylazo) resorcinol. Analytical sensitivities, being defined by the slopes of calibration curves, are 0.93, 0.54, and 0.11 Abs/ $\mu$g/ml for iron, copper, zinc, respectively. Detection limits render around a few tenth of one ng/ml. Precisions evaluated by replicate analysis of real sample are better than 10% RSD. Due to the lack of certified standards for rainwater, the accuracy of the method could not be assessed directly. However, the results of this method agree well with those by inductively coupled plasma mass spectrometry. Analytical results for a suite of Seoul rainwaters are presented herein.

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.189-195
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• 1993

This study conducted to investigate the effect of school lunch prgram on the blood composition of 50 children at the age 11 to 12 years old. Concentration of serum total protein, albumin, zinc and copper were measured at the begining of school lunch program(pre-feeding group) and at the one year later taken school lunch program(post-feeding group). Serum total protein and albumin concentrations in post-feeding group were higher than those in pre-feeding group, but showed no significant difference between groups. While serum zinc and copper concentrations in post-feeding group were significantly lower than those in pre-feeding group. Results indicated that school lunch program effective for improvement of potein nutrition in school children and it is nessessary futher investigation to disease the concentrations of serum zinc and copper in this age.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.896-901
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• 2005

The microstructure and electrical properties of praseodymium-based zinc oxide varistors were investigated at various cobalt oxide contents in the range of $0.5{\~}5.0 mol\%$. The ceramic density increased in the range of $5.25{\~}5.55 g/cm^3$ with increasing cobalt oxide content. The varistor doped with cobalt oxide of $1.0 mol\%$ exhibited the highest nonlinearity, with 66.6 in nonlinear exponent and 1.2 $\mu$A in leakage current. The donor concentration, density of interface states, and tamer height were in the range of $(1.06{\~}1.69){\times}10^{18}/cm^3$, $(3.11 {\~}3.56){\times}10^{12}/cm^2$, and 0.80${\~}$1.07 eV, respectively.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.183.2-184
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• 2003

Zinc is known to have an inhibitory effect on apoptosis and an antioxidative effect scavenging reactive oxygen species (ROS) under oxidative stress. We studied the influence of zinc on cadmium-induced apoptosis especially associated with ROS in MCF-7 human breast carcinoma cell line. For the determination of appropriate experimental concentration and time, we excecuted MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay and DNA fragmentation assay. (omitted)

• Journal of Environmental Science International
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• v.17 no.9
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• pp.943-947
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• 2008

For the purpose of safety identification, the concentrations of heavy metals in seaweeds collected from Busan Gijang coastal area were investigated. The average concentration of metals had a level of as high as the order of manganese (2.76 ppm)>zinc(2.11 ppm)>copper(0.59 ppm)>arsenic (0.092 ppm)>lead(0.06 ppm)> mercury(0.03 ppm)>cadmium(0.026 ppm). The contents of manganese and zinc were highly detected from P. elliptica, copper and mercury from agar, cadmium from sea mustard and arsenic from wild sea mustard, respectively. The metal contents of seaweeds varied with kinds of samples, but high level for the safety can be found in these samples. Because P. elliptica had shown a clear selectivity for both manganese and zinc, this seaweed could be useful as a bioindicator for these two metal pollution.

• Fibers and Polymers
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• v.2 no.1
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• pp.131-134
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• 2001

Living cationic polymerization behaviors of isobutyl vinyl ehters (IBVE), initiated by iodomethyl methyl ether (IMME)/zinc iodide ($Znl_2$) have been investigated. The polymerization was carried out at 0, -15, and $-30^{\circ}C$ in toluene. It was found that the rate of polymerization increased as the IMME concentration increased and decreased as temperature decreased. 100% conversion was always achieved without exception. Furthermore, the number-average molecular weight ($M_{n}$) of polymers increased in direct proportion to monomer conversion. The molecular weights of polymers were in good agreement with the theoretical values, calculated on the basis that one polymer chain was formed by one IMME molecule and the values of polydispersity index are always less than 1.2, revealing the living nature. The living nature was also confirmed by synthesis of poly(IBVE-b-TBVE) by subsequent monomer addition of t-butyl vinyl ether (TBVE).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.277-283
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• 2009

In this paper, aluminum doped zinc oxide (ZnO:Al) thin films on plastic substrate such as poly carbonate (PC), polyethylene terephthalate (PET) were prepared by RF magnetron sputtering method for flexible solar cell applications. Effects of the sputter pressure on the structural, electrical and optical properties were investigated. The crystallinity and the degree of the (002) orientation were deteriorated with increasing the sputter pressure. When the sputter pressure was higher, the conductivity of ZnO:Al films was improved because of the high carrier concentration and the Hall mobility. High quality ZnO:Al films with resistivity as low as $1.9{\times}10^{-3}{\Omega}-cm$ and the optical transmittance over 80 % in the visible region have been obtained on PC substrate at 2 mTorr.

• Journal of the Korean institute of surface engineering
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• v.21 no.4
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• pp.168-175
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• 1988

The nickel0zinc allot depositions have been studjen in ammonium chloridw added chloride baths to fine out the effects of ultrasonic irradiation for the electrodeposition processes. The compositions of deposited alloys, the current efficiencies, corrosion resistance and brightness in various conditions of electrodeposition were investigated, in the range of ultrasonic irradiation of 50,500 and 1,000kc/s respectively. The results obtained are as follows; 1. the ratio of nikel to zinc in the deposit increased according 시 the ammonium chloride concentration in irradiated baths. 2. The current efficiencies became also higer in the irradiated bath. 3. Ammonium ions in solution seem to retard formation of zinc hydroxide. 4. The corrsion resistance and brightness of the deposits are dependent upon nickel content of deposits which ranges 10-18%(wt)nickel in the irradiated baths and 11-15%(wt)in ninirradisted baths. 5. The corrosion resistance and brightnes of the deposited are appreciably better in the irradiated baths than in non-irradiated bath with the mole ratio of 3.4(NH+4/Ni+++Zn++).