• Journal of Plant Biology
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• v.14 no.1
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• pp.1-4
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• 1971

To determine the amylase fromation mechanism and the effect of GA. in germinating barley seeds, they were divided into embryo-less seed, isolated embryo, aleurone layer and pure endosperm etc., treated with GA, and cultured separately or in mixed lots. The result obtained are as follows. 1) The amylase of barley seed is formed in the aleurone layer under the effect of inducing materials excreted from the embryo. 2) The embryonic materials amylase formation could be substituted for by GA. Therefore it can be presumed that the substance produced by the embryo which induces amylase synthesis is probably GA or material similar to it.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.27-31
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• 1988

Biosynthesis and processing of cytoplasmic mRNA from heterogenous nuclear RNA (hn-RNA) in Aspergillus phoenicis were studied by $^{3}H$-uridine labeling and synchronous culture techniques during their life cycle. Incorporations of $^{3}H$-uridine into hn-RNA and mRNA were most rapid in vesicle-phialide fromation stage and diminished in hyphal growth stage. The processing of cytoplasmic mRNA from hn-RNA was proceeded more rapidly in hyphal growth and conidiophore formation stages than in conidia and vesicle-phialide formation stages. The specific radioactivities of hn-RNA and mRNA were very high in vesicle-phialide formation stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.265-270
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• 1995

In orthogonal cutting a new approach for modeling of burr formation process when tool exits workpiece is proposed. The approach is based on the rigid-plastic FEM combined with the ductile fracture criterion and the element kill method. The approach is applied to simulate a plane strain cutting process. The results of the FEM are compared with those of the experiment. It is shown that the fracture location and fracture angle as well as cutting force can be predicted using the proposed approach with a good correlation to experimental results.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.1-6
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• 2000

The effects of partial substitution of fluorine on physical properties were studied in Ag-sheathes tapes of $Tl_{0.8}Pb_{0.2}Sr_{1.8}Ba_{0.2} Ca_{2.2}Cu_3O_yF_x (0{\leq}x{\leq}1)$ nominal compositions. The tapes were prepared using the powder-in-tube method incorporating an in-situ reaction method. $CuF_2$ was used as a source of F. It was found that F-doping in Tl-1223 system resulted in a decrease in formation temperatire of Tl-1223 phase. and thus significantly deteriorated their superconducting properties. Such disadvantages seem to originate by the fromation of non-beneficial phases such as SrF2 in the early stage of the powder preparation process.

• Journal of the Korean Ceramic Society
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• v.27 no.4
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• pp.543-547
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• 1990

Numerous researchers have observed the bubble fromation at SiC/SiO2 interface from 130$0^{\circ}C$ to 1$700^{\circ}C$. According to thermodynamic calculation, the bubble could be formed from the microscopic impurities which result from the chemical vapor deposition of SiC. When C-impurity is present at the interface, it is calculated that the bubble is formed at 1511$^{\circ}C$ and when Si is present, the bubble is formed at 177$0^{\circ}C$. These results are very close to the prior observations, but the calculation can not explain the observation of bubble below 150$0^{\circ}C$.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.263-269
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• 1986

Membrane proteins of facultatively anaerobic Escherichia coli K12 which was logarithmically grown in aerobiosis and anaerobiosis were compared on 5 to 10% liner gradient gel electrophoresis (Na Dod $SO_4 -PAGE$). Membrane proteins were formed as different patterns between aerobiosis and anaerobiosis. Among them, 91Kdal protein (pbp1a) was not synthesized in aerobiosis and 60Kdal protein (fts cluster), in anaerobiosis. Thereby cells cultured aerobically were differenciated as diversiform cell shape, comparing cells cultured anaerobically and the latter were resistant to penicillin G. Thus it is believed that in facultative anaerobes atmospheric oxygen regulated the synthesis of membrane proteins and even the expression of equivalent genes, and moreover alleviated the resistance to an antibiotic penicillin.

• Journal of the Korean Ceramic Society
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• v.32 no.2
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• pp.239-247
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• 1995

Chalcogenide glasses with compositions of Ge10Se90-xTex(X=0~50 at.%) were prepared in order to investigate the effects of Te substitution on the transmission characteristics of Ge-Se glasses in the 8~12 ${\mu}{\textrm}{m}$ wavelength region. Absorption coefficients were observed to decrease with Te addition, indicating the improved transmission capabilities of Ge-Se-Te glasses as compared to binary Ge-Se glasses. XRD analysis of crystallized glasses suggested the formation of weaker Se-Te and/or Te-Te bonds with addition of Te substituting for Se in stronger Se-Se bonds. Incorporation of Te in excess of 20at% resulted in the formation of hexagonal Te phases when crystallized. It is speculated that the presence of Te-Te bonds with highly metallic bond character resulted in the enhanced crystallization tendencies of glasses. Fromation of Te-rich chains through gradual replacement of Se-Se with Se-Te and/or Te-Te bonds was further supported by decreases in glass transition and crystallization temperatures.

• Applied Biological Chemistry
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• v.34 no.1
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• pp.1-7
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• 1991

Optimum conditions for hydrolysis of sunflower seed by pepsin and for plastein formation by pepsin were determined. The optimum conditions for hydrolysis of sunflower seed were pH 1.5, $45^{\circ}C$, enzyme concentration 2%, substrate concentration 2%, and hydrolysis time 24hr. The optimum conditions for sunflower seed-plastein formation were 50% substrate, pH 4.5, $50^{\circ}C$, 0.25% pepsin and 18hrs reaction time. To verify plastein fromation from concentrated prptic hydrolysate of sunflower seed, thin layer chromatography was performed. The TLC pattern of concentrated peptic hydrolysate of sunflower seed was different from that of its plastein. The TLC pattern of concentrated peptic bydrolysate of sunflower seed and at of its plastein indicated that plastein was different material from the hydrolysate.

• Journal of the Korean Ceramic Society
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• v.37 no.4
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• pp.314-319
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• 2000

Microstructueral development and electrical properties in ZnO-Bi2O3-ZnAl2O4 system were investigated with ZnAl2O4 content(0.1~1.0 mol%). The shrinakge of specimens started around $700^{\circ}C$ and finished at 110$0^{\circ}C$, reaching a maximum shrinkage rate at 80$0^{\circ}C$. The shrinkage rate is strongly related to the fromation of a Bi-rich liquid. The increase of the ZnAl2O4 content inhibited the grain growth of ZnO. Most of ZnAl2O4 particles located at the grain boundaries were about 2~3${\mu}{\textrm}{m}$. ZnO grain size changed little up to 110$0^{\circ}C$, but increased markedly above 115$0^{\circ}C$, especially at lower ZnAl2O4 content. Drastic decreasing in breakdown voltage(Vb) with increasing temperature is expected to be dependent on the ZnO grain size and the distribution of the largest grains between the electrode. The nonlinear I-V characteristic was significantly influenced by the ZnAl2O4 content, which exhibited a maximum value at about 15${\mu}{\textrm}{m}$ of ZnO grain size.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.47-54
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• 1990

In order to investigate physiological characteristics of fusants by interspecific protoplast fusion of the genus Cellulomonas, protoplasts of Cellulomonas flavigena NCIB 12901 and Cellulomonas bibula NCIB 8142 were fused and cell wall regenerated. To give gene maker, C. bibula was treated with 500 ug/ml NTG for 1 hr and arginine requiring auxotrophic mutants were isolated. Protoplasts of the genus Cellulomonas were obtained by treatment with $600{\mu}{\textrm{g}}$/ml lysozyme, and 0.5M sorbitol was optimal for osmotic stabilizer on protoplast fromation. Protoplast fusion was enhanced by 40% PEG)M.W.6,000) containing 25 mM $CaCl_{2}$ at $30^{\circ}C$ for 30 min and fusion frequency between C. bibula and C. flavigena was $5\times 10^{-4}$. Processes of protoplast formation, cell wall regeneration and protoplast fusion were obsdrved by scanning electron microscope. By comparing enzyme activities of cellulase, exocellobiohydrolase, .betha.-glucosidase of the parent strains of Cellulomonas with those of thier mutants and fusants, fusants with increased enzyme activity were obtained. By the studies on nutritional requirement, antibiotic resistance, cellulolytic enzyme activities, type of peptidoglycan and motility of two mutants and fusants, fusants were proved to be recombinant of both mutant strains.