• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.976-980
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• 2001

In this study, P $b_{0.88}$(L $a_{a}$N $d_{l-a}$)$_{0.08}$(M $n_{1}$3/S $b_{2}$3/)$_{0.02}$ $Ti_{0.98}$ $O_3$system ceramics were manufactured for 20 MHz class resonator application. Electromechanical coupling factor, mechanical quality factor and dynamic range of 3rd overtone thickness vibration mode were measured as the variations of La and Nd molar ratio. Mechanical quality factor and dynamic range at $\alpha$=0.6 composition ceramics showed the highest value of 2, 691 and 52.37 dB, respectively. The tempearture coefficient of resonant frequency measured from -2$0^{\circ}C$ to 8$0^{\circ}C$ showed an excellent value of 5ppm/$^{\circ}C$ at $\alpha$ = 1 composition ceramics. ceramics.s.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제26권2호
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• pp.59-73
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• 2019

In this paper, a version of the boundary Schwarz Lemma for the holomorphic function belonging to $\mathcal{N}$(${\alpha}$) is investigated. For the function $f(z)=z+c_2z^2+C_3z^3+{\cdots}$ which is defined in the unit disc where $f(z){\in}\mathcal{N}({\alpha})$, we estimate the modulus of the angular derivative of the function f(z) at the boundary point b with $f(b)={\frac{1}{b}}\int\limits_0^b$ f(t)dt. The sharpness of these inequalities is also proved.

• 한국미생물·생명공학회지
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• 제33권4호
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• pp.260-266
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• 2005

본 실험에서는 MRF가 다량 존재하는 RBL-2H3 세포주에 다양한 PKC isotype별 억제제를 처리하여 in vitro상에서 Na, K-ATPase $\alpha$1L3를 이용한 pull-down assay와 RBL-2H3 세포를 이용한 membrane fractionation을 실시하였다. 그 결과 HRF는 in vitro에서 $\alpha$1L3와 결합한다는 사실을 재확인 할 수 있었고 실제 세포주 내에서 Na,K-ATPase와 결합한다는 것을 알 수 있었다. 사용한 약물로부터 PKC $\alpha,\;\beta,\;\delta$뿐 아니라 protein phosphatase 2B(PP2B)도 HRF와 $\alpha$1L3의 결합에 관여한다는 사실을 알 수 있었다. 또한 이들 PKC, PP2B에 의해 인산화된 HRF 분자는 cytosolic fraction으로 이행할 수 있으며 이러한 결과는 탈인산화된 HRF가 Na,K-ATPase와 결합하여 Na, K-ATPase의 기능을 조절한다고 추정할 수 있다. 그러나 약물자체가 histamine 분비에 영향을 미칠 수 있으며 cytosolic HRF보다 exocytosis된 HRF가 histamine를 더 분비하도록 할 수 있으므로, 약물을 전처리한 세포에 외부에서 HRF를 첨가하여 histamine이 유리되는 정도가 어떻게 변화하는지를 HRF를 가하지 않은 결과와 비교해야 할 것이다.

• 한국식품저장유통학회지
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• 제22권2호
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• pp.182-189
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• 2015

4종류의 커피 원두(CS, Colombia superimo; EY, Ethiopia yirgacheffee; IM, Indonesia mandheling; IMM, India monsooned malabar AA)를 생두(raw coffee bean)와 각각 다른 온도(200, $250^{\circ}C$)와 시간(10, 15, 20 min)으로 로스팅하였으며, 최적의 로스팅 조건을 찾기 위하여 로스팅 중에 변화되는 pyrazine을 비롯한 몇 가지 성분과 항산화, 항당뇨 효과를 조사하였다. Caffeine 함량은 로스팅 정도에 따라 크게 차이를 보이지 않았으나, 5-caffeoylquinic acid와 total phenolic compounds는 대체로 로스팅이 강해질수록 크게 감소하였다. Pyrazine 화합물은 IMM에서 가장 많이 생성되었으며, $250^{\circ}C$에서는 시간이 경과할수록 급격히 줄어들었다. DPPH 라디칼 소거활성은 같은 처리농도에서의 BHT와 ${\alpha}$-tocopherol의 활성에 비하여 대부분 80% 이상의 효과를 나타내었다. 한편 FRAP assay에서는 로스팅 정도가 강해질수록 활성이 약간 감소하였다. ${\alpha}$-Glucosidase 저해활성은 유의할 만한 수준이었으나, $250^{\circ}C$에서 20분 roasting할 경우에는 활성이 80% 이상 줄어들었으며, ${\alpha}$-amylase 저해활성도 유사한 경향이었다. 이러한 결과로 로스팅 정도에 따른 생리활성과 커피의 고소한 향과 초콜릿 향을 내는 pyrazine 화합물의 생성을 종합적으로 보았을 때, $200^{\circ}C$에서 15분정도 로스팅하는 것이 가장 최적의 조건인 것으로 판단하였다. 따라서 이러한 결과는 커피산업에서 로스팅 조건을 달리한 원두커피의 향과 생리활성이 높은 커피를 생산하는데 활용될 수 있을 것이라 기대된다.

• Journal of Nutrition and Health
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• 제31권5호
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• pp.906-913
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• 1998

This study an analyzes the effects of the P/S ratio of dietary lipids and antioxidant vitamin supplements on serum lipids level and fatty acid profile, the degree of lipid peroxidation, and the antioxidant enzyme activities in the liver of rats treated with 7,12-dimethylbenz($\alpha$) anthracene(DMBA). P/S ratio of dietary lipids was made into 0.5, 1 and 2 by mixing palm oil, soybean oil, sesame oil and perilla oil at 10%(w/w) fat level and n-6/n-3 ratio was fixed to 4. Antioxidant vitamin of $\alpha$-tocopherol or $\beta$-carotene was supplemented in addition to vitamin mixture which was given at 1 % of the standard diet. female Sprague-Dawley strain rats, about 60 days old, were divided into three groups(LP : low P/S ratio(0.5), MP : medium P/S ratio (1.0), HP , high P/S ratio(2.0)) and each group was sub-divided into three groups(S ; standard, T ; tocopherol supplemented, C : carotene supplemented): Two weeks after feeding experimental diets, all groups were treated with a single dose of DMBA(2mg/100g BW) by gastric intubation and fed experimental diet for 9 week. The results were as follows ; 1) Serum total cholesterol(TC) level was not significantly influenced by diet but tended to be lower in HP groups compared to LP and MP groups. Triglyceride level was the highest in LP groups and the lowest in $\alpha$-tocopherol supplemented groups. 2) Thiobarbituric acid reactive substance(TBARS) level, representing lipid peroxidation in hepatic microsome, tended to be increased as the unsaturation of dietary lipids increases. $\alpha$-Tocopherol supplement significantly decreased TBARS level. 3) The activities of superoxide dismutase(SOD) and glutathione peroxidase(GSHPx) in hepatic cytosol showed the tendency to be high with increasing P/S ratio of dietary lipids. SOD activity was not significantly influenced by antioxidant vitamin, but GSHPx activity was significantly increased in $\alpha$-tocopherol supplemented groups. In summary, high polyunsaturated fat diet was effective on reducing the serum level of total cholesterol and triglyceride, while it increased unsaturation and peroxidizability of serum fatty acid. With increasing P/S ratio of dietary lipids, lipid peroxidation was increased in the liver and antioxidant enzyme system was induced to inhibit lipid peroxidation against oxidative damage. $\alpha$-Tocopherol supplement was effective in lowering lipid peoxidation, but $\beta$-carotene supplement did not exhibit antioxidant effect. (Korean J Nutrition 31(5) 906~913, 1998)

• 한국수산과학회지
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• 제47권5호
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• pp.516-521
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• 2014

A bacterium producing ${\alpha}$-galactosidase (${\alpha}$-$\small{D}$-galactoside galactohydrolase, EC 3.2.1.22) was isolated. The isolate, KM-1 was identified as Bacillus coagulans based on its 16S rRNA sequence, morphology, and biochemical properties. ${\alpha}$-Galactosidase activity was detected the culture supernatant of B. coagulans KM-1. The bacterium showed the maximum activity for hydrolyzing para-nitrophenyl-${\alpha}$-$\small{D}$-galactopyranoside (pNP-${\alpha}Gal$) at pH 6.0 and $50^{\circ}C$. It hydrolyzed oligomeric substrates such as melibiose, raffinose, and stachyose liberating a galactose residue, indicating that the B. coagulans KM-1 ${\alpha}$-galactosidase hydrolyzed ${\alpha}$-1,6 linkage. The results suggest that the decreased stachyose and raffinose contents in fermented soybean meal are due to the ${\alpha}$-galactosidase activity.

• 열처리공학회지
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• 제23권5호
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• pp.233-238
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• 2010

The phase transformations and the shape memory effect in In-rich Pb alloys and In rich-Sn alloys have been studied by means of X-ray diffractometry supplemented by metallographic observations. The alloys containing 12~15 at.%Pb transform from the ${\alpha}_2$ (fct) phase to the ${\alpha}_1$ (fct) phase by way of an intermediate phase (m phase) on cooling. The results of X-ray diffraction show that the metastable intermediate phase is observed both on cooling and heating, and has a face-centered orthorhombic (fco) structure. It is concluded that the ${\alpha}_1{\rightleftarrows}{\alpha}_2$ transformation is expressed by the ${\alpha}_1{\rightleftarrows}m{\rightleftarrows}{\alpha}_2$ transformation both on usual cooling and heating with the rate more than $8{\times}10^{-3}$ K/s. The $m{\rightleftarrows}{\alpha}_2$ transformation takes place with a mechanism involving macroscopic shear and are of diffusionless (martensitic) type. The temperature hysteresis in the two transformations is 10~13 K between the heating and cooling transformations. The alloys containing 0~11 at.%Sn are -phase solid solutions with a face centered tetragonal structure (c/a > 1) at room temperature, the axial ratio increasing continuously with tin content. The In-(11~15) at.%Sn alloys are mixtures of ${\alpha}$ and ${\beta}$ phases, the ${\beta}$ phase having a f. c. tetragonal structure (c/a < 1). The alloys containing more than 15 at.%Sn are ${\beta}$-phase solid solutions. The In-(12.9~15.0) at.%Sn alloys show a shape memory effect only when quenched to the temperature of liquid nitrogen, although their effect becomes weak and finally disappears after keeping at room temperature for a long time. The ${\beta}{\rightarrow}{\alpha}^{\prime}$ phase transformation is of the diffusionless (martensitic) type, and takes place between 330 K at 12.9 at.%Sn and 150 K at 14.5 at.%Sn. The hysteresis of transformation temperatures on heating and cooling is considerably large (29~40 K), depending on the composition. Both In-Pb and In-Sn alloys showed distinct the shape memory effects.

• Applied Biological Chemistry
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• 제38권4호
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• pp.302-307
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• 1995

김치로부터 Listeria spp.를 억제하는 박테리오신을 생산하는 젖산균 4균주를 선발하여 Leuconostoc mesenteroides subsp. mesenteroides (2균주), Leuconostoc paramesenteroides 및 Pediococcus pentosaceus로 동정하였다. 실험한 모든 Listeria monocytogenes 균주들은 모든 분리 균주의 박테리오신에 의해 억제되었으나, L. denigrificans 28과 L. welchimeri 89는 Leu. paramesenteroides 분리균주에 의해 억제되지 않았다. 분리균주들 중에서 P. pentosaceus의 박테리오신이 가장 항균활성이 높았고, 항균범위도 넓었다. Leuconostoc 분리균주들의 박테리오신의 항균활성은 pronase E에 의해 완전히 불활성화 되었으나 P. pentosaceus의 것은 완전히 불활성화되지 않았다. 분리균주들의 박테리오신은 catalase, ${\alpha}$-amylase, lysozyme 및 $100^{\circ}C$ 30분의 열처리에 대해서 안정하였다.

• 접착 및 계면
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• 제2권2호
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• pp.11-19
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• 2001

트리카프릴메틸 암모니움 클로라이드를 상이동촉매로 사용하여 $Na_2S_2O_8$의 수용액과 톨루엔의 이상계에서 질소분위기하에 $60^{\circ}C$에서 스티렌의 라디칼중합을 행하였다. 중합시의 초기 중합속도는 촉매와 $Na_2S_2O_8$의 초기공급 농도보다는 수용액 상에서의 4급 암모늄양이온과 퍼록시디슬페이트 음이온의 농도로 나타낼 수 있었다. 관찰된 초기중합속도를 사용하여 분균일 액-액계에서의 순환 상이동에 의한 개시과정을 포함한 중함메카니즘을 밝힐 수 있었다. 폴리스티렌의 점도평균분자량은 $Na_2S_2O_8$의 농도에 역비례하였는데, 라디칼 중합메카니즘에 의하여 $[Q^+]([S_2O{_8}^{2-}]{\alpha}_2)^{1/2}$로 나타내어졌다.

• 폴리머
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• 제29권2호
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• pp.161-165
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• 2005

Octamethylcyclotetrasiloxane$(D_4)$과 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane$(D_3^{MePh})$을 1,1,3,3,-tetramethyl-1,3-divinylsiloxane(MVS)과 평형중합시켜 dimethylsiloxane과 methylphenylsiloxane block unit를 갖는 $\alpha,\omega-vinyl$ poly(dimethyl-methylphenyl)siloxane prepolymer(VPMPS)를 제조하였으며 또한 $D_4$와 1,3,5-trimethyl-1,3,5-trifluoropropylcyclotrisiloxane $(D_3^{M3,F3P})$을 1,1,3,3-tetramethyldisiloxane과 평형중합시켜 dimethylsiloxane과 methyltrifluoropropyl siloxane block unit를 갖는 $\alpha,\omega-hydrogen$ poly(dimethyl-methyltrifluoropropyl)siloxane prepolymer(HPDMFS)를 제조하였다. VPMPS, HPDMFS, 열전도 필터 및 촉매를 고속교반기에 가하고 $130^{\circ}C$에서 컴파운딩하여 저경도 poly(organosiloxane) rubber를 제조하였으며 이의 가교밀도는 $115^{\circ}C$에서 oscillation rheometer를 이용하여 측정하였다. 열전도성 충전제로 구상 알루미나를 Horsfield's packing model에 따라 평균입자경의 분포를 조절하여 제조한 composite TC-POXR-2의 열전도도가 1.13 W/mK, 그리고 TC-POXR-4가 1.19 W/mK였으며 이는 단일입자경을 갖는 충전제를 가하여 제조한 경우보다 높은 열전도성을 나타내었다.