• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1337-1342
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• 1998

To investigate an effect of phase separation on precipitation characteristics of ZnS microcrystals in ma-trix glass ZnS doped borosilicate glasses for nonlinear optical applications were prepared by melting and pre-cipitation process. ZnS dopant contributed to phase separation promotion which increased the phase separa-tion of the matrix glass within immiscibility region. It was also found that ZnS as phase separation promoter showed a similar contribution for some selected glass compositions in miscibility region. The precipitation of ZnS microcrystals occurred in thephase separable glass compoitions. The radius of ZnS microcrystals in-creased with increasing the heat treatment temperature and Na2O contents of matrix glass composition. The ZnS particle sizes estimated by effective mass approximation ranged from about 30 to 80${\AA}$ It was suf-ficiently small to show quantum confinement effect.

• Journal of Life Science
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• v.8 no.2
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• pp.145-157
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• 1998

We isolated 100 Vobrio sp. from marine products and sea from July to September, 1997. We attemped on purification of hemolysin produced by Vibrio sp. The growth, hemolysin production patterns by the 100 strains of Vibrio sp. showed identical, in general. V. unlnificus ys-1 produced hemolysis as the higtest titer. The optimal culture conditions for the hemolysin production by the V. vunificus ys-1 are followings; 1. Hemolysin production was optimal dering the late exponetial phage. 2. Maximal growth, hemolysin production were in heart infusion broth. 3. Maximal yields of hemolysin was obtained when the heart infusion broth had an intial pH of 8.0, 3$0^{\circ}C$, 3% NaCL. Hemolysin was purified from culture filtrate of the strain by ammonium sulfate recipitation, ion exchange and hydrophobic interaction chromatography. The results were as follows; 1. Hemogeneity of the purified hemolysin was demonstrated by revealing single band on SDS-PAGE. The molecular weight of purified hemolysin was 45KDa. 2. The absorbance rattern in ultraviolet wsa typical of those seen with most proteinb with 280nm. 3. Purified hemolysin was atable at 5$0^{\circ}C$ but 7$0^{\circ}C$ of the acivity was lost by heating for 30 min at 6$0^{\circ}C$/ Optimal temperature of purified hemolysin was 35$^{\circ}C$. 4. Purified hemolysin was stable at the pH range of 6~9, but in the less the pH5.0. above the pH 9.0, the hemolysin activity was lost completely.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.163-169
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• 1989

Seasonal climatic factors associated with tobacco quality grade and production rate were analyzed. The degree of influence on yield distribution rate in high guality tobacco leaues was highly positive with the average temperature in early May, but negatively related to those in late May and early June. Positive correlations were noticed between the degree of influence and sunshine hours in Middle June, late June and late May in decrease order, while negative degree of influence was higher in early May than in late May, The order influenced by recipitation in a positive direction was early May, late May and middle May. Negative influence was noticed in middle and early June with a great degree.