• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.115-120
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• 1995

Diazotization of 2-Amino-5-nitrophenol was Synthesized by the direct diazotization method. The diazonium salts are usually stabilized in the from of double salts. The double salts of zinc chloride are the Commonest, and the double salt method is Specially applicable to the yield-up of coupling. The azo dye(2-naphthol-1-(2'-diazo-5'-nitrophenol)) is Converted into a chromium Complex by heating($100^{\circ}C$) with chromic formate, and DMF. The removal of inorganic salts from dyestuffs was performed in DMF solvent. This effect was more pronounced. From these results, It was obtained to liquid dyestuffs of metal complex with High fastness and high adsorption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.882-887
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• 1996

Production of yeast diet has been carried out in batch fermenters under optimum culture conditions. The fermentation of Candida utilis on a $2\%$ complex medium resulted in 1.22 g/L/h productivity and $65\times10^8$ viable cells/ml, and the addition of $15{\mu}M$ zinc to the medium increased both the productivity and the number of viable cells just a little more. In the case of the fermentation of Kluyveromyces fragilis, the highest value of the biomass productivity, 1.94 g/L/h, was obtained on a $2.5\%$ fructose medium with $70\times10^8$ viable cells/ml, and $1\%$ peptone was found to be a growth factor in this fermentation. When $3.5\%$ NaCl was added to the given medium, both the biomass productivity and the number of viable cells decreased significantly in each fermentation, but this may be considered to preserve yeast diet long without osmotic lysis.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.17 no.1
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• pp.1-15
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• 2013

In this paper the three dimensional wave propagation in a homogeneous isotropic thermo elastic cylindrical panel embedded in an elastic medium (Winkler model) is investigated in the context of the L-S (Lord-Shulman) theory of generalized thermo elasticity. The analysis is carried out by introducing three displacement functions so that the equations of motion are uncoupled and simplified. A Bessel function solution with complex arguments is then directly used for the case of complex Eigen values. This type of study is important for design of structures in atomic reactors, steam turbines, wave loading on submarine, the impact loading due to superfast train and jets and other devices operating at elevated temperature. In order to illustrate theoretical development, numerical solutions are obtained and presented graphically for a zinc material with the support of MATLAB.

• Journal of the Semiconductor & Display Technology
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• v.4 no.4 s.13
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• pp.9-12
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• 2005

Characteristics of ZnO films grown on $Si-SiO_2$ substrates at temperatures of $200\sim400^{\circ}C$ by metalorganic chemical vapor deposition were investigated. The growth rates and mobilities of ZnO films were dependent on growth temperatures. The field-effect mobilities measured in thin-film transistor structure were $15cm^2/Vsec$.

• YAKHAK HOEJI
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• v.46 no.5
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• pp.307-312
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• 2002

The synthesis of new 6-exomethylene penams with benzothiazole ring was described. The 6,6-dibromopenam 5 was treated with $CH_3$MgBr and carbaldehyde 4 to afford the 6-bromo-6-(1-hydroxy-1-methyl)penicillanate 6, which was reacted with acetic anhydride to give acetoxy compound 7. The deacetobromination of acetoxy compound 7 with zinc and acetic acid gave 6-exomethylene penams, Z-isomer 8 and E-isomer 9, which was oxidized to sulfones 10 by m-CPBA. The p-methoxybenzyl compounds 6~10 were deprotected by AlCl$_3$ and neutralized to give the sodium salts 11~15.

• Corrosion Science and Technology
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• v.4 no.1
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• pp.15-18
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• 2005

Hydroxyapatite(HAp) was synthesized using the waste sludge from semiconductor process and used as an anticorrosive pigment. The water absorption of coating pigmented with anticorrosive pigment and the corrosion at interface between coating and substrate were monitored using AC impedance techniques. The anticorrosive performance of HAp was compared with those of red lead(RL) and zinc potassium chromate(ZPC), which have been known as representative anticorrosive pigments. The amount of absorbed water in ZPC- and HAp- pigmented coatings was much higher compared to that in RL-pigmented and unpigmented film. However, it seems that the water absorbed into HAp- or ZPC-pigmented film is beneficial to anticorrosive function. The anticorrosive performance of HAp is superior or at least comparable to those of ZPC and RL. The excellent anticorrosive properties of HAp can be explained by its passivating ability, caused by the reaction of the soluble component of HAp with Fe to form iron phosphate in the presence of water.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.714-715
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• 2006

The Application of powder metallurgy (PM) aluminum structural parts is at its early growing stage, despite of some automotive applications. The market potential for PM aluminum, however, is large. Growth is expected from the market expansion of the existing applications and new applications, including the replacements of aluminum and zinc based castings and some ferrous PM automotive parts by PM aluminum. Compared to castings, PM is an efficient mass production technology. The PM aluminum is more competitive than die casting for some automotive applications. Besides weight saving leading to performance improvement, the total cost increase for aluminum PM parts is less than 15% compared to ferrous PM automotive parts. The future is promising for PM aluminum.

• Journal of the Korean Ceramic Society
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• v.23 no.4
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• pp.69-77
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• 1986

Single crystals of zinc tungstates were grown by the Czochralski method. To obtain the seed crystals various methods were employed including 4 points platinum wirse which dipped the melt and the capillary action from the melt led the 3 differently oriented seeds such as [100], [010] and [001] directions. Optimum growing conditions were observed as neck diameter 2mm rotation speed 50-60 rpm maximum diameter 15mm and pulling rate 0-10 mm/hr. Dendrites covered on the olidified surface in a platinum crucible were turned out to be [001] direction because obviously this crystal has the strong [001] preferential growth habit. The (100) and (010) planes of single crystals showed the slip planes and the (010) plane showed the perfect cleavage surface.

• Journal of Environmental Health Sciences
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• v.15 no.1
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• pp.75-79
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• 1989

This study was carried out to investigate water quality of mineral water located in Nam san. 8 sites were pointed out by ramdom sampling and tested for 12 items in May and December 1988. The results were as follows: 1. The range of pH value in all sites was 5.4 - 6.8. 2. NH$_{3}$-N concentrations were suitable for drinking water criteria in winter season but site 1 was not for drinking water criteria. 3. NO$_{3}$-N concentrations were suitable for drinking water criteria in all samples. 4. Most of heavy metals were detected small amount, and espically zinc were detected much amount in all sites (0.01-0.32). 5. Coliform was not detected in all sites .in summer season but site 4 and 8 were detected in winter season.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.92-92
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• 2008

ZIO(Indium-doped Zinc Oxide) 박막은 고밀도, 고순도 ZIO($In_2O_3$ : 3.33, 6.50, 9.54, 12.44, 15.22 wt%) 타겟 5개를 이용하여 RF 마그네트론법으로 기판온도 RT에서 non-alkali 유리 기판위에 증착하였다. 스퍼터 가스로서는 Ar 가스를 사용하였다. $In_2O_3$ 9.54 wt%인 타겟을 이용하여 RT에서 증착한 박막이 가장 낮은 비저항 $9.13{\times}10^{-4}{\Omega}cm$를 나타내었다. ZIO 박막의 전기적 특성은 Hall 효과 측정장비, 박막의 결정구조는 X-선 회절(XRD), 광학적 특성은 UV 측정장비를 사용하여 측정하였다.