• Journal of Microbiology
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• 제33권4호
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• pp.302-306
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• 1995

E. coli was tested for their ability to uptake cadmium intracellularly, and the effect of zinc and calcium on cadmium toxicity to E. coli was observed. In addition, the effect of zinc and calcium on the uptake of cadimium was also studied. This study showed that living E. coli cells took up more cadmium than the dead cells. E. coli in the log phase uptake cadimiumm more actively than E. coli in the stationary phase. These results suggested that there may be metabolic reactions or compounds which encourage the uptake of cadimium. This study also showed that cadimium was sequestered by cell components of which molecular weight is about 30,000. Adding of zinc and calcium chloride reduced cadmium toxicity in E. coli and encouraged intracellular uptake by E coli. However adding of heavy metal solutions helped the microorganisms to adsorb more cadmium. Extremely high or low concentrations of zinc, however, did not affect cell viability.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1993년도 ACT 93
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• pp.771-775
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• 1993

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2000년도 춘계학술발표회 초록집
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• pp.24-24
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• 2000

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1873-1875
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• 2005

The effect of zinc oxide as an inhibitor for the corrosion of steel in concrete environment was studied by weight loss measurements, potential-time behaviour and anodic polarization technique. The salient features of the investigation were: in 100% OPC extracts, the passivity of steel was readily destroyed, however extracts containing various concentration of zinc oxide, the passivity of steel was maintained even in the presence of 30,000 ppm of chloride. Alkalinity of concrete was maintained by the addition of zinc oxide. The efficiency of the inhibitor was found to increase with increasing inhibitor concentration. Addition of zinc oxide in the range 3 to 4% by weight of cement was sufficient to protect the rebars.

• 대한지역사회영양학회지
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• 제5권3호
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• pp.484-492
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• 2000

In an attempt to figure out the relationship between zinc status and taste acuity of old and young women, dietary zinc intake, urinary zinc excretion, and taste acuity were determined for 118 women. Zinc intake was measured by 2-day food records and food frequency method. Urinary zinc excretion was measured from urine samples collected for twenty four hours. Body fat, lean body mass (LBM), and total body water were measured by bio-impedence. Average dietary zinc intake by food record was 4.15$\pm$1.33mg (=35% if Korean RDA) for the old women and 5.41$\pm$2.76mg (=25% of RDA) for young women. When zinc intake was measured by a frequency method, the average intakes of the old and young women were 3.5$\pm$1.7mg 4.5$\pm$1.9mg, respectively. It appears that dietary zinc intake of young women was significantly higher than that of the old women. Average urinary zinc excretion of the subjects was 0.27$\pm$0.16mg in the elderly and 0.24$\pm$0.13mg in young women, which indicated a marginal zinc status. However, zinc status was not significantly different between old and young women. Correlation analysis indicated that zinc intake and urinary zinc excretion were positively related to BMI and LBM in young women. The old women (m=49) showed significantly higher taste detection thresholds than young subjects (n=47) for both sweet and salty tastes. Recognition thresholds for sodium chloride and sucrose were not significantly different between old and young women. The lower the taste thresholds for salty taste, the higher the average dietary zinc intake. However, taste perception concentration was not related to the urinary zinc excretion level.

• 한국표면공학회지
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• 제20권3호
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• pp.118-126
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• 1987

The Zn-Al composite electroplating was studied by using chloride zinc bath containing metal hydroxides $(Zn(OH)_2,\;Al(OH)_3))$ and aluminium powder. The size of Al powder codeposited in the beaker bath with Al powder of-400 mesh was under 10${\mu}m$. The Zn-Al composite was electro-deposited at 40$^{\circ}C$ in the ranges of current density of 5-50 A/$dm^2$ in the flowing electrolyte. The content of aluminium particles codeposited increased slightly with increasing flow rate of electrolyte from 0.5 m/sec to 1.0 m/sec, and decreased with increasing current density from 5 A/$dm^2$ to 50 A/$dm^2$. The content of aluminium particles codeposited by using the electrolyte containing zinc hydroxide(0.1M) was 2~4 wt%. The Al powder was codeposited mainly near the surface layer of the electrodeposits. The dissolution rate of aluminium particles in the electrolyte containing 0.1M $Zn(OH)_2$ and Boric acid was 0.41 g/l. day in comparison with 1.5 g/l. day dissolution rate in pure chloride bath.

• 한국환경보건학회지
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• 제25권3호
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• pp.23-28
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• 1999

Phosphate removal through adsorbent, such as activated alumina, powdered aluminum oxide, flyash, blasted furnace slag and other materials, is commonly and widely practiced. The purpose of this study was to improve the removal efficiency of phosphorus in waste sludge earned at seafood processing factories. To investigate the utility and the feasibility of this sludge disposal process, experiment was carried out with a batch process. As a result, phosphate removal appears to increase with increasing adsorbent does, but shows no changes at an adsorbent does over 5g/l. With increasing ratios of initial phosphate concentration to adsorbent does, the amount of removed phosphate is increased while phosphate removal(%) is decreased. Wasted sludge, treated with zinc chloride chemically, represented a better efficiency than the untreated activated sludge and zinc chloride itself, when they reacted with phosphate solution.

• 자원환경지질
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• 제26권3호
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• pp.421-429
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• 1993

Dissolution reactions of chemical grade zinc sulfide and natural sphalerite were studied in ferric chloride solution as an oxidant. To enhance the leaching reaction, ultrasonic technique was employed in this investigation. For the reaction with pure zinc sulfide, chemical reaction was the rate limiting step in the range of low conversion irrespective of applying ultrasonic wave. And the diffusion through liquid film instead of diffusion through product layer of free sulfur was the rate determining step because ultrasonic vibration removes the product from reaction zone. In the case of sphalerite with the ultrasonic vibrator, it was found that inert mineral layer diffusion was the rate determining step, in which the elemental sulfurs formed were removed by the ultrasonic action. Experimental results showed that the ultrasonic technique proved to be the methods which can significants improve the leaching performance.

• 한국염색가공학회지
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• 제14권2호
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• pp.109-109
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• 2002

A study has been made of the dry-jet-wet spinning of PAN copolymer fibers using 60% aqueous zinc chloride solution as solvent and 25∼40% aqueous zinc chloride solution as non-solvent. The technological characteristics of this method were that small streams of dope were extruded from the die and allowed to pass through a short distance of air gap(about 10mm) before entering the spinning bath for full coagulation. This work showed the importances which coagulation condition, stretch ratio and fiber tenacity up to 10.5 g/d could be obtained with elongation of 11∼16%. Individual fibers were evaluated on the basis of density and mechanical properties such as tenacity and elongation etc.

• 한국염색가공학회지
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• 제14권2호
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• pp.33-39
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• 2002

A study has been made of the dry-jet-wet spinning of PAN copolymer fibers using 60% aqueous zinc chloride solution as solvent and 25∼40% aqueous zinc chloride solution as non-solvent. The technological characteristics of this method were that small streams of dope were extruded from the die and allowed to pass through a short distance of air gap(about 10mm) before entering the spinning bath for full coagulation. This work showed the importances which coagulation condition, stretch ratio and fiber tenacity up to 10.5 g/d could be obtained with elongation of 11∼16%. Individual fibers were evaluated on the basis of density and mechanical properties such as tenacity and elongation etc.