• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.1030-1033
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• 2003

This paper presents the deposition characterization of polycrystalline silicon films by the HWCVD(Hot-wire Chemical Vapor Deposition) method at low substrate($300^{\circ}C$). The filament temperature, pressure and $SiH_4$ concentration were determined to be a critical parameter for the deposition of poly-Si films. Series A was deposited under the conditions of $1380^{\circ}C$(Tf), 100 mTorr and $2{\sim}10%\{SiH_4/(SiH_4+H_2)\}$ for 60 min. Series B was deposited under the conditions of $1400{\sim}1450^{\circ}C$ (Tf), 30 mTorr and $2{\sim}12%$ for 60 min. The physical characteristics were measured by Raman and FTIR spectroscopy, dark and photoconductivity measurements under AM1.5 illumination.

• 한국가축번식학회지
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• 제26권4호
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• pp.361-368
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• 2002

The onset of pronucleus formation and DNA synthesis in porcine oocytes following the injection of porcine or murine sperm was determined in order to obtain insights into species-specific paternal factors that contribute to fertilization. After 44h in vitro maturation, spermatozoa was injected into the cytoplasm of oocytes. After injection, all oocytes were transferred to NCSU23 medium and cultured at 39'E under 5% CO2 in air. Similar frequencies of oocytes with female pronuclei were observed after injection with porcine sperm or with murine sperm. In contrast, male pronuclei formed 8 to 9 h following the injection of porcine sperm, and 6 to 8 h following the injection of murine sperm. After pronucleus formation maternally derived microtubules were assembled and appeared to move both male and female pronuclei to the oocyte center. A few porcine oocytes entered metaphase 22 h after the injection of murine sperm, but normal cell division was not observed. The mean time of onset of S-phase in male pronuclei was 9.7 h following porcine sperm injection and 7.4 h following mouse sperm injection. These results suggested that DNA synthesis was delayed in both pronuclei until the sperm chromatin fully decondensed, and the sperm nuclear decondensing activity and microtubule nucleation abilities of the male centrosome are cell cycle dependent.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.339-345
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• 2009

We evaluated the activity and abundance of the crude-oil-degrading bacterium Nocardia sp. H17-1 during bioremediation of oil-contaminated soil, using real-time PCR. The total petroleum hydrocarbon(TPH) degradation rate constants(k) of the soils treated with and without H17-1 were $0.103\;d^{-1}$ and $0.028\;d^{-1}$ respectively. The degradation rate constant was 3.6 times higher in the soil with H17-1 than in the soil without H17-1. In order to detect and quantify the Nocardia sp. H17-1 in soil samples, we quantified the genes encoding 16S ribosomal RNA(16S rRNA), alkane monooxygenase(alkB4), and catechol 2,3-dioxygenase(23CAT) with real-time PCR using SYBR green. The amounts of H17-1 16S rRNA and alkB4 detected increased rapidly up to 1,000-folds for the first 10 days, and then continued to increase only slightly or leveled off. However, the abundance of the 23CAT gene detected in H17-1-treated soil, where H17-1 had neither the 23CAT gene for the degradation of aromatic hydrocarbons nor the catechol 2,3-dioxygenase activity, did not differ significantly from that of the untreated soil($\alpha$=0.05,p>0.22). These results indicated that H17-1 is a potential candidate for the bioaugmentation of alkane-contaminated soil. Overall, we evaluated the abundance and metabolic activity of the bioremediation strain H17-1 using real-time PCR, independent of cultivation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.906-909
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• 2006

The secondary electron emission coefficient $({\gamma})$ of the cathode is an important factor for improving the discharge characteristics of AC-PDPs because of its close relationship to discharge voltage. In AC-PDPs, MgO is most widely used as a surface protective layer. In this experimental, we have investigated the electronic structure of the energy band structure of the MgO layer responsible for the high ${\gamma}$. The MgO layers have been deposited by electron beam evaporation method, where the $O_2$ partial pressures have been varied as 0, $5.2{\times}10^{-5}$ torr, $1.0{\times}10^{-4}$ torr, and $4.1{\times}10^{-4}$ torr, in this experiment. It is noted that work function that is energy gap between surface and first defect level of MgO layer has the lowest value for the highest O2 partial pressure of $4.1^{\ast}10^{-4}$ Torr.

• Applied Biological Chemistry
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• 제37권4호
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• pp.310-314
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• 1994

솔잎으로부터 프리 라디칼 소거 작용이 있는 물질을 분리하고, 여러 기기 분석 결과에 근거하여 4-hydroxy-5-methyl-3[2H]-furanone으로 동정하였다. 아울러 xylose와 glycine의 Maillard 반응을 통하여 이 물질을 합성하였다. 이 물질은 1,1-diphenyl-2-picrylhydrazyl(DPPH) 프리 라디칼에 대해 소거 작용을 보였으며(100 M의 DPPH의 50%를 환원 시키는데 필요한 농도, 즉 $SC_{50}=26\;{\mu}M$) 이는 구조적으로 유사한 공지의 항산화 물질인 $4-hydroxy-2,5-dimethyl-3[2H]-furanone(SC_{50}=53\;{\mu}M)$과 $3-hydroxy-2-methyl-{\gamma}-pyrone(SC_{50}=4.0\;mM)$에 비해 강력한 것이다. 4-Hydroxy-5-methyl-3[2H]-furanone은 3,4-dihydroxyphenylalanine과 linolenic acid의 자동 산화에 대해서 억제 작용을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.116-122
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• 2007

An efficient enzyme system for the synthesis of L-tyrosine was developed using a fed-batch reactor with continuous feeding of phenol, pyruvate, and ammonia. A thermo- and chemostable tyrosine phenol-lyase from Symbiobacterium toebii was employed as the biocatalyst in this work. The enzyme was produced using a constitutive expression system in Escherichia coli BL21, and prepared as a soluble extract by rapid clarification, involving treatment with 40% methanol in the presence of excess ammonium chloride. The stability of the enzyme was maintained for at least 18 h under the synthesis conditions, including 75 mM phenol at pH 8.5 and $40^{\circ}C$. The fed-batch system (working volume, 0.51) containing 1.0 kU of the enzyme preparation was continuously fed with two substrate preparations: one containing 2.2 M phenol and 2.4 M sodium pyruvate, and the other containing 0.4 mM pyridoxal-5-phosphate and 4M ammonium chloride (pH 8.5). The system produced 130g/I of L-tyrosine within 30h, mostly as precipitated particles, upon continuous feeding of the substrates for 22 h. The maximum conversion yield of L-tyrosine was 94% on the basis of the supplied phenol.

• Journal of Applied Biological Chemistry
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• 제58권3호
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• pp.287-290
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• 2015

본 연구에서는 콩의 배축(hypocotyls)에서 분리된 4종의 soyasaponin(Aa, Ab, bg, DDMP)에 대해 RBL-2H3 세포를 이용하여 항알레르기 활성을 확인하고자 하였다. RBL-2H3 세포에서 soyasaponin 화합물들의 세포독성을 확인해 본 결과, 4종 모두 세포독성이 없었고 ${\beta}$-hexosaminidase assay를 통해 비만세포의 탈과립 억제 효능을 확인해 본 결과 대조군으로 사용한 Ketotifen fumarate($IC_{50}$: 38.77mM)와 비교하여 4종 모두 ${\beta}$-hexosaminidase 억제 효능이 있는 것을 확인하였다. 또한, soyasaponin 화합물들은 RBL-2H3 세포에서 탈과립 후 유리되는 대표적인 물질인 histamine의 분비 억제에도 효능이 있음을 확인하였고 이 중 Soyasaponin DDMP가 가장 효능이 우수한 것으로 판단된다.

• Journal of Dairy Science and Biotechnology
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• 제35권4호
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• pp.266-269
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• 2017

This objectives of this study were to assess the pH and titratable acid (TA) and conduct sensory evaluation of the high-protein yogurt supplemented with Oxya chinensis sinuosa (grasshopper). High-protein yogurt containing Oxya chinensis sinuosa powder displayed TA of 0.93% to 1.1%, and a pH of 4.3 or 4.4. There were no significant differences between the control and treated groups in pH and TA. Organoleptic evaluations revealed that, except for color and texture, taste, flavor, and overall acceptability showed decreased trends in proportion to the amount of Oxya chinensis sinuosa powder. Further studies will explore the potential of Oxya chinensis sinuosa powder as a protein with health benefits for humans.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.62-62
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• 2003

Charged particles can be accelerated to relativistic high energies by high power (＞ terawatt) laser beams. We have a research project on laser and plasma-based advanced accelerators in Center for Advanced Accelerators at Korea Electrotechnology Research Institute (KERI), in which the 2 TW (1.4 J／700 fs) Ti：sapphire／Nd：glass hybrid laser system and a He plasma will be used for particle acceleration experiments. In this presentation, we introduce the ongoing research activities and the planned experiments at KERI.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2004년도 International Symposium on Powder Materials and Processing
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• pp.106-106
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• 2004