• Korean Journal of Materials Research
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• v.16 no.8
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• pp.466-472
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• 2006

The electrical, dielectric properties, and its stability of ZPCCL-based varistors were investigated for different sintering temperatures in the range of $1230{\sim}1300^{\circ}C$. As the sintering temperatures increased, the varistor voltage decreased in the range of $777.9{\sim}108$ V/mm, the nonlinear coefficient decreased in the range of $77.9{\sim}7.1$, and the leakage current increased in the range of $0.3{\sim}50.6\;{\mu}A$. The stability of electrical and dielectric characteristics was obtained from sintering temperature of $1260^{\circ}C$. the varistors sintered at $1260^{\circ}C$ marked the high electrical and dielectric stability, with $%{\Delta}{V_{1mA}=+1.9%,\;%{\Delta}{\alpha}=-10.6%,\;%{\Delta}I_L=+20%\;and\;%{\Delta}tan\;{\delta}=+9.9%$ for DC accelerated aging stress state of $0.95V_{1mA}/150^{\circ}C$/24 h.

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.441-448
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• 1998

A cellobiose-utilizing recombinant yeast having $\beta$-glucosidase activity was developed for ethanol production from a mixture of glucose and cellobiose. Using $\delta$-sequences of Tyl transposon of yeast as target sites for homologous recombination, a heterologous gene of $\beta$-glucosidase was integrated into the chromosome of Saccharomyces cerevisiae. The $\delta$-integrated recombinant yeast, Saccharomyces cerevisiae L2612 (Pb-BGL), showed perfect mitotic stability even in nonselective media and showed ca. 1.5 fold higher $\beta$-glucosidase activity than the recombinant yeast harboring the $2\mu$-based plasmid vector system. A mathematical model was developed to describe the $\beta$-glucosidase formation and ethanol production from the Saccharomyces cerevisiae L2612 ($p\delta-BGL$). The model newly described that the heterologous $\beta$-glucosidase production mediated by ADH1 promoter is regulated by glucose and repressed by ethanol.

• Journal of the Korean Ceramic Society
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• v.38 no.4
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• pp.370-379
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• 2001

PLD(pulsed laser deposition) 기법을 이용하여 LaAl $O_3$(100) 기판 위에 L $a_{0.67}$ $A_{0.33}$Mn $O_{3-{\delta}}$ (A=Ca, Sr, Ba) 에피 박막을 성장하였다. 박막의 격자 상수 및 스트레인 상태는 GID(grazing incidence X-ray diffraction)법과 투과 전자 현미경 법을 이용하여 조사하였다. 박막의 <001> 방향은 기판 표면의 수직방향에 평행하게 놓였으며, 박막의 단위포는 기판과의 격자 불일치에 기인하여 a/c=0.98인 의사-정방정 페롭스카이트(pseudo-tetragonal perovskite) 구조를 가졌다. A 자리의 양이온 반경이 증가함에 따라 단위포의 체적, $\varepsilon$$^{∥}$, 그리고 $\varepsilon$$_{⊥}$이 각각 증가하였다. L $a_{0.67}$ $A_{0.33}$Mn $O_{3-{\delta}}$ (A=Ca, Sr, Ba) 박막의 온도 및 자장에 따른 전기 전도 특성 MR(%), Tc, $T_{MI}$ 들을 조사하였으며, 이 결과들을 박막의 구조적 특성과 상관하여 고찰하였다.여 고찰하였다.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.204-205
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• 2003

Nano 결정립 N $d_2$F $e_{l4}$B+F $e_3$B 복합상 자성 리본은 Extractive melt spinner의 wheel speed를 달리하여 제조하였다. 초기 조성은 N $d_4$F $e_{77.5}$ $B_{18.5}$이고, 이후 제조한 자성 리본의 자기특성은 VSM 및 AGM(Alternating gradient magnetometer)으로 측정하였다. wheel speed 1500rpm, $650^{\circ}C$에서 10분간 열처리한 자성 리본에서 $B_{r}$ = 11.73 kG, $_{i}$ $H_{c}$ = 3.082 kOe, (BH)$_{max}$ = 12.28 MGOe의 자기특성이 나타났다. 이러한 자기특성 원인 규명을 위해 $\delta$M plot과 뫼스바우어 분광학을 사용하였다. $\delta$M plot을 통해 exchange coupling은 초미세립 복합상의 잔류자속밀도에 큰 영향을 미치는 것으로 판단된다. 또한, 뫼스바우어 분광학을 통해 경자성상(N $d_2$F $e_{l4}$B)과 연자성상 F $e_3$B의 부피분율비가 7:3 정도일 때 가장 최적의 자기특성을 발현하였다. 이 경우에 초미세립 복합상의 상호작용력이 가장 크게 발현하는 것으로 판단된다.단된다..된다..된다..

• Phonetics and Speech Sciences
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• v.8 no.2
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• pp.1-9
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• 2016

This paper investigated the rhythmic features of speakers of English as a lingua franca in Asian contexts. A speech corpus of 150 conversations between speakers of English in Asia with different L1 backgrounds was collected and %V, ${\Delta}V$, VarcoV, and nPVI-V of each speaker were analyzed. It was found that L1 difference of the speakers and the speakers' daily use of English influenced %V, while the speakers' daily use of English influenced ${\Delta}V$. The gender difference of the speakers also affected the rhythm of the utterances in VarcoV. A weak correlation between the two speakers' rhythm in each conversation was also found in %V and ${\Delta}V$. No significant effects were found in nPVI-V. The results revealed that the speakers tended to accommodate the rhythm of their utterance to that of the interlocutors'. Further study on the speaking rate of the speakers is required to overcome some inconsistencies found in the results of the rhythmic metrics used in this study.

• Korean Journal of Pharmacognosy
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• v.43 no.1
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• pp.6-9
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• 2012

The $CH_2Cl_2$ soluble part of the leaves of Helianthus tuberosus L. (Compositae) exhibited a potent cytotoxic activity against the cultured human tumor cell lines including A-549, SK-OV-3, SK-MEL-2, XF498 and HCT-15 in vitro. Bioassaydirected fractionation of the $CH_2Cl_2$ soluble part of this plant led to the isolation of four cytotoxic sesquiterpene lactones having ${\alpha}$-methylene-${\gamma}$-lactone ring in the molecule. On the basis of physical and spectral evidences, their structures were characterized as ${\Delta}^{4,15}$-isoatripliciolide tiglate (1), ${\Delta}^{4,15}$-isoatripliciolide methacrylate (2), budlein A isobutylate (3) and budlein A tiglate (4). The ${\Delta}^{4,15}$-isoatripliciolide tiglate (1) showed the most potent cytotoxic activity ($0.26{\mu}M<ED_{50}<2.16{\mu}M$) against all of the cell lines tested.

• YAKHAK HOEJI
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• v.21 no.3
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• pp.167-171
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• 1977

A new assay method for delta-l-dehydrogenated-3-ketoco-rticosteroid in the presence of proteinous material or whole-cell-enzyme and 3-ketocorticosteroid has been developed. This method makes use of the linear relationship between the ratio of absorbances at 265 nm and at 242 nm and the fractional concentration of delta-1-3-ketosteroid. Theoretical values were calculated based on the absorbances of proteinous material at fixed concentrations of the 3-ketosteroid and delta-1-dehydrogenated-3-ketosteroid. The values obtained experimentally showed good agreement with the values obtained experimentally showed good agreement with the values theoretically predicted. The new assay method developed for the steroid mixtiure containing proteinous material is of some practical importance. The use of such assay method enables one to determine the enzyme activity and the rate of enzyme reaction or conversion rather quickly, easily and accurately. By the use of this assay method, the reaction kinetics of whole-cell-enzyme has also been studied. It was found that it followed the simple Michaelis-Menten type enzyme kinetics. Also the reversibility of this reaction with actively metabolizing cell was examined. It was found that delta-l-dehydrogenated-3-ketosteroid could not be hydrogenated reversibly to 3-ketosteroid by this enzyme system.

• Journal of Technologic Dentistry
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• v.37 no.4
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• pp.199-203
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• 2015

Purpose: The purpose of this in vitro study was to evaluation the effect of shade on all ceramic restoration based zirconia according to cooling rate on Firing. Methods: 10 specimens applied to the dentin porcelain were made on the zirconia. After 5 specimens of the first group were burned in the furnace, these were put out rapidly. And after 5 specimens of the second group were burned in the furnace, these were put out slowly later 15 min. All specimens were measured $L^*$, $a^*$, $b^*$ using spectrophotometer, there were calculated 10 mean(SD) of descriptive statistics with SPSS program. These data were used for ${\Delta}E^*$ with color difference equation. Independent t tests were performed between 2 groups. Results: $L^*$, $a^*$, $b^*$ of 2 groups was statistically significant respectively (p<0.001), ${\Delta}E^*$ was 4.55 value. Conclusion: This study showed effect of shade on all ceramic restoration based zirconia according to cooling rate on Firing.

• Biomedical Science Letters
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• v.23 no.1
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• pp.44-47
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• 2017

S100A8 and S100A9 are associated with myeloid cell differentiation, chemotactic activities, adhesion of neutrophils, and apoptosis. In this study, we investigated the contribution of S100A8 and S100A9 to differentiation of the human eosinophilic leukemia cell line, EoL-1. S100A8 and S100A9 increased the number of vacuole per one cell and the protein expression of EPO and MBP. Rottlerin, an inhibitor of protein kinase C delta ($PKC{\delta}$), inhibited the EoL-1 cell differentiation induced by S100A8 and S100A9. These results suggest that S100A8 and S100A9 may regulate the differentiation of eosinophilic progenitors. Moreover, these findings may shed light on elucidation of eosinophil differentiation due to S100 proteins.

• Journal of the Korean Ceramic Society
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• v.38 no.8
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• pp.693-697
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• 2001

고상반응법으로 이론 밀도의 약 92%의 소결 밀도를 갖는 입방정계의 새로운 이온전도체 L $a_{2-x}$S $r_{x}$M $o_{2-y}$C $r_{y}$ $O_{9-{\delta}}$(x=0, 0.05, y=0, 0.1)를 제조하였다. 교류 복소임피던스는 3$50^{\circ}C$~90$0^{\circ}C$의 온도범위에서 공기중에서 측정하여, EQUIVCRT 모델링 소프트웨어로 해석하였다. 상 전이온도인 58$0^{\circ}C$ 전.후로 임피던스 스펙트럼에 큰 차이가 있었으며, 전기전도도는 L $a_2$M $o_2$ $O_{9}$ 시편의 경우 7$50^{\circ}C$에서 3$\times$$10^{-2}$ S$cm^{-1}$ /로 우수하였으며, 활성화 에너지는 고온 상 영역에서는 0.89 eV, 저온 상 영역에서는 1.12 eV이었다. 순수한 L $a_2$M $o_2$ $O_{9}$과 비교하여 Cr 치환효과는 크지 않았으나, Sr 치환 시에는 상 전이온도의 감소와 전기전도도의 증가 현상을 보였으며, 전이온도 부근에서의 전기전도도 변화 폭은 작았다.다.