• Journal of Plant Biology
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• 제14권1호
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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.

• 미생물학회지
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• 제26권1호
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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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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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.

• 한국초전도ㆍ저온공학회논문지
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• 제2권1호
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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.

• 한국세라믹학회지
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• 제27권4호
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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$0^{\circ}C$.

• 미생물학회지
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• 제24권3호
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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.

• 한국세라믹학회지
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• 제32권2호
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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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• 제34권1호
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• pp.1-7
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• 1991

해바라기씨 단백질에서 plastein을 합성 이용하기 위해 먼저 해바라기씨를 pepsin을 이용해 가수분해하는 최적 조건과, plastein을 합성하는 최적 조건을 구하였다. 최적 가수분해 조건은 pH 1.5, $45^{\circ}C$, 2% 기질농도와 2% pepsin 농도에서 24시간 반응시키는 것이었고 plastein 합성의 최적조건은 기질농도 50%, pH 4.5, $50^{\circ}C$, 0.25% pepsin 농도에서 18시간 반응시키는 것이었다. Plastein의 생성을 확인하기 위해 thin layer chromatography를 실시한 결과 해바라기씨 농축가수분해물의 TLC pattern과 plastein의 TLC pattern이 하나의 spot를 제외하고는 다르게 나타났는데 이는 plastein과 기질이 다른 것임을 표시하는 것이었다.

• 한국세라믹학회지
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• 제37권4호
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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.

• 미생물학회지
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• 제28권1호
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• pp.47-54
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• 1990

섬유소를 분해할 수 있는 Cellutomonas flavigena NCIB 12901 과 Cellulomonas bibula NCIB 8142의 종간 원형질체 융합을 하고 그로부터 얻은 융합체의 특성을 조사하였다. C. bibuta의 원형질체는 lysozyme(600Ieιllulomoηas libula NCIB 8142의 종간 원형 섣처l 융 한응 하고:1로부터 얻은융합셰익 특성을 조사하였다 . C bibula의 원형선셰는 lysozyme $600{\mu}{\textrm{g}}$/ml)를 6시간 처리하여 얻었으며, 삼투안정제로는 O.5M sorbitol의 최저이었고 원형질체 재생률은 6.7%였다. 원형질체 융합은 25mM $CaCl_{2}$를 포함하는 40% PEG (M.W.6000)를 $30^{\circ}C$에서 30분간 처리함으로 수행하였고 C. bibuιl와 C. flavigeηa의 융합 빈도는 $5\times 10^{-4}$으로 원형질체 형성 및 합체를 얻었고, 모균주와 융합체의 영양요구성, 항생물질 내성, 효소활성, 세포벽 성분, 운동성 등을 비교하여 융합체는 모균주의 재조합체임을 밝히었다.