• 한국안전학회지
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• 제8권4호
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• pp.27-40
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• 1993

High temperature tensile tests, steady state creep tests, Internal stress tests and creep rupture tests using A17075 alloy( $T_{6}$ ) were performed over the temperature range of 9$0^{\circ}C$~50$0^{\circ}C$ (0.4 $T_{m}$ ~0.85 $T_{m}$ ) and stress range of 0.64~17.2(kgf/$\textrm{mm}^2$). The main results obtained in this paper were as follows. (1) The activation energies for yielding at the temperature of 0.4 $T_{m}$ ~0.75 $T_{m}$ were calculated to be 25.7~36.5kcal/mol, which were nearly equal to the activation energies for creep. (2) At around the temperature of 9$0^{\circ}C$~12$0^{\circ}C$ and under the stress level of 10~17.2(kgf/$\textrm{mm}^2$), and at around the temperature of 200~41$0^{\circ}C$ and under the stress level of 1.53~9.55(kgf/$\textrm{mm}^2$) and again at around the temperature of 470~50$0^{\circ}C$ and under the stress level of 0.62~l.02(kgf/$\textrm{mm}^2$), the applied stress dependence of steady state creep rate $n_{measu}$ measured were, respectively, 3.15, 6.62 and 1.1, which were in good agreement the calculated stress dependence $n_{ealeu}$ obtained by the difference of the applied stress dependence of the Internal stress and the ratio of the internal stress to the applied stress. (3) At the temperature range of 0.4~0.43 $T_{m}$ , and at the temperature range of 0.52~0.75 $T_{m}$ and again at the temperature range of 0.82~0.85 $T_{m}$ , the activation energies $Q_{measu}$ obtained by steady state creep rate, respective, 26. 16, 34.9, 36.2 and 36.1kcal/mol, which were in good agreement with those obtained with the activation energies under constant effective stress and the temperature dependence of Internal stress. (4) At the temperature range of the 0.52~0.73 $T_{m}$ and under the stress level of 1.53~9.55(kgf/$\textrm{mm}^2$), the stress dependence of rupture life(n’) measured was 6.3~6.6, which was in good agreement with the stress dependence of steady state creep rate(n). And at the same condition the activation energy for rupture( $Q_{f}$ ) measured was 32.0~36.9kca1/mol, which was also in good agreement with the activation energy obtained by steady state creep rate ( $Q_{c}$ ). (5) The rupture life( $t_{f}$ ) might be represented by athermal process attributed to the difference of the applied stress dependence of the internal stress and the ratio of the internal stress to the applied stress, and the thermal activated process attributied to the temperature dependence of the internal stress as $t_{f}$ = A'$\sigma$$_{a}$ ｛n(1-d $\sigma$$_{i}$ /d $\sigma$$_{a}$ )/(1-$\sigma$$_{i}$ / $\sigma$$_{a}$ )｝.exp[｛ $Q_{c}$ $^{*}$-( $n_{o}$ R $T^2$/ $E_{(T)}$) (d $E_{(T)}$/dT) - ( $n_{0}$ R $T^2$/ $\sigma$$_{a}$ - $\sigma$$_{i}$ ) (d $\sigma$$_{i}$ /dT)｝/RT]. (6) The relationship betwween Larson-Miller rupture parameter and logarithmic stress was linearly decreased, so creep rupture life of Al 7075 alloy seemed to be predicted exactly with Larson-Miller parameter.meter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.137-137
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• 2009

Thin-film transistors (TFTs) that can be prepared at low temperatures have attracted much attention due to the great potential for flexible electronics. One of the mainstreams in this field is the use of organic semiconductors such as pentacene. But device performance of the organic TFTs is still limited by low field effect mobility or rapidly degraded after exposing to air in many cases. Another approach is amorphous oxide semiconductors. Amorphous oxide semiconductors (AOSs) have exactly attracted considerable attention because AOSs were fabricated at room temperature and used lots of application such as flexible display, electronic paper, large solar cells. Among the various AOSs, a-IGZO was considerable material because it has high mobility and uniform surface and good transparent. The high mobility is attributed to the result of the overlap of spherical s-orbital of the heavy pest-transition metal cations. This study is demonstrated the effect of thickness channel layer from 30nm to 200nm. when the thickness was increased, turn on voltage and subthreshold swing were decreased. a-IGZO TFTs have used a shadow mask to deposit channel and source/drain(S/D). a-IGZO were deposited on SiO2 wafer by rf magnetron sputtering. using power is 150W, working pressure is 3m Torr, and an O2/Ar(2/28 SCCM) atmosphere at room temperature. The electrodes were formed with Electron-beam evaporated Ti(30nm) and Au(70nm) structure. Finally, Al(150nm) as a gate metal was evaporated. TFT devices were heat treated in a furnace at $250^{\circ}C$ in nitrogen atmosphere for an hour. The electrical properties of the TFTs were measured using a probe-station to measure I-V characteristic. TFT whose thickness was 150nm exhibits a good subthreshold swing(S) of 0.72 V/decade and high on-off ratio of 1E+08. Field effect mobility, saturation effect mobility, and threshold voltage were evaluated 7.2, 5.8, 8V respectively.

• Journal of Microbiology and Biotechnology
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• 제26권12호
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• pp.2171-2178
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• 2016

Polyester cloth (PC) was selected as a prospective inexpensive substitute separator material for microbial fuel cells (MFCs). PC was compared with a traditional Nafion proton exchange membrane (PEM) as an MFC separator by analyzing its physical and electrochemical properties. A single layer of PC showed higher mass transfer (e.g., for $O_2/H^+/ions$) than the Nafion PEM; in the case of oxygen mass transfer coefficient ($k_o$), a rate of $50.0{\times}10^{-5} cm{\cdot}s^{-1}$ was observed compared with a rate of $20.8{\times}10^{-5}cm/s$ in the Nafion PEM. Increased numbers of PC layers were found to reduce the oxygen mass transfer coefficient. In addition, the diffusion coefficient of oxygen ($D_O$) for PC ($2.0-3.3{\times}10^{-6}cm^2/s$) was lower than that of the Nafion PEM ($3.8{\times}10^{-6}cm^2/s$). The PC was found to have a low ohmic resistance ($0.29-0.38{\Omega}$) in the MFC, which was similar to that of Nafion PEM ($0.31{\Omega}$); this resulted in comparable maximum power density and maximum current density in MFCs with PC and those with Nafion PEMs. Moreover, a higher average current generation was observed in MFCs with PC ($104.3{\pm}15.3A/m^3$) compared with MFCs with Nafion PEM ($100.4{\pm}17.7A/m^3$), as well as showing insignificant degradation of the PC surface, during 177 days of use in swine wastewater. These results suggest that PC separators could serve as a low-cost alternative to Nafion PEMs for construction of cost-effective MFCs.

• 한국식품과학회지
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• 제27권6호
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• pp.985-990
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• 1995

Grapefruit 종자추출물(GFSE)에는 박테리아와 곰팡이류들에 대하여 항균 효과를 갖는 성분이 있다고 알려져 있다. 배나무에 병반에서 분리한 Enterobacter pyrinus도 GFSE를 가하여 준 배지에서 생육이 억제되었다. 대조군이 stationary phase로 접어든 배양 20시간까지 GFSE의 최종 농도가 0.01%를 함유한 배지에서 E. pyrinus는 전혀 성장하지 못하였다. 항균 성분을 분리하기 위하여 GFSE를 용매추출하여 친수성 분획과 소수성 분획으로 나누었을 때 억제 효과는 소수성 분획에서 관찰되었다. GFSE가 에너지 대사에 관여하는 몇가지 효소에 미치는 영향을 조사하여 본 결과, hexokinase, glucose-6-phosphate dehydrogenase, malate dehydrogenase와 succinate dehydrogenase 등에는 별다른 효과를 나타내지 않았다. 세포막에 미치는 영향을 알아보기 위하여 ${\beta}-galactosidase$의 인위적 기질인 ONPG의 분해 여부를 조사한 결과, GFSE는 세포막에 영향을 끼침을 관찰하였다. GFSE의 항균 성분을 분리 확인하기 위해서 HPLC $C_{18}$ reverse phase column chromatography를 하여 5개의 peak를 얻었으며, 이중 1개의 분획에서 강한 항균 활성을 검출하였다. 이 분획을 GC-Mass로 사용하여 분석한 결과 1-chloro-2-methyl-benzene (o-toluene), N,N-dimethyl-benzenemethaneamine, 1-[2-(2-ethylethoxy)ethoxy]-4- (1,1,3,3-tetramethyl)-bezene 이외에 분획의 대부분을 차지하는 1개의 물질을 포함하여, 확인하지 못한 3개의 물질이 있음을 알았으며, GFSE의 항균활성을 보이는 성분은 새로운 물질일 가능성을 시사하였다.

• 대한수의학회지
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• 제42권1호
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• pp.45-54
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• 2002

The study was carried out to characterize the pharmacokinetics after intravenous (iv, 20 mg/kg) and oral (p.o. 100 mg/kg) administration as oxytetracycline (OTC) and tiamulin (TIA) mixture in swine and to determine interaction between OTC and TIA against various pig pathogenic bacteria. The antibacterial effects of OTC in combination with TIA in vitro showed synergistic effect against Salmonella typhimurium 1925, Pasteurella multocida Type A, P. multocida Type D, Krebsiella Pneumoniae 2001, K. Pneumoniae 1560, K. Pneumoniae 2208, Haemophillus pleuropneumonia S 2, and H. pleuropneumonia S 5, but against additive effect E. coli K88ab and S. choleraesuis on the basis of fractional inhibitory concentration (FIC) index. On the while, after i.v. and p.o. administration of OTC and TIA mixture, each OTC and TIA concentrations in plasma were fitted to an open two-compartment model. After i.v. administration of OTC-TIA mixture, the mean distribution half-life ($T_{1/2{\alpha}}$) of OTC and TIA in plasma showed 0.29 h and 0.17 h, and the mean elimination half-life ($T_{1/2{\beta}}$) of those was 4.36 h and 6.64 h, respectively. The mean volume of distribution at steady state ($Vd_{ss}$) of OTC and TIA was $0.85{\ell}/kg$ and $2.44{\ell}/kg$, respectively. After oral administration of OTC and TIA mixture, the mean maximal absorption concentrations ($C_{max}$) of OTC and TIA were $0.60{\mu}g/m{\ell}$ at 1.07 h ($T_{max}$) and $1.68{\mu}g/m{\ell}$ at 1.85 h ($T_{max}$), respectively. The mean elimination half-life ($T_{1/2{\beta}}$) of those showed 6.84 h and 6.36 h. In conclusion, we could suggest in this study that the combination of OTC and TIA may be recommended for the antibacterial therapy against polymicrobial infections, and both OTC and TIA showed large distribution to tissues and high $C_{max}$ after p.o. administration.

• 한국건설순환자원학회논문집
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• 제12권2호
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• pp.196-205
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• 2024

본 연구에서는 노면에서 생성된 타이어 마모입자가 강우 강도에 따라 환경 구획별로 이동하는 양을 예측하고자, 도로 노면에서 타이어 마모입자의 샘플 포집과 정량화 분석 연구를 수행했다. 샘플 포집은 3일 평균 강우(0-60 mm/day) 발생 후 도로 노면이 완전히 건조된 2일 후, 도로 노면에 남아있는 타이어 마모입자의 샘플을 포집했다. 포집된 샘플은 크기와 밀도 분리를 통해 타이어 마모입자만을 분리했고, 강우가 없는 날(0 mm/day)의 타이어 마모입자 60.2 g 값을 기준으로 강우 이후 노면에 남아있는 타이어 마모입자의 함량의 차이를 산출하면, 강우 강도에 따라 0-49.4 g의 타이어 마모입자가 환경 구획으로 이동할 수 있는 것으로 확인했다. 또한, 강우 강도가 60 mm/day 일 때 5 mm/day와 비교해 타이어 마모입자의 환경 구획별 이동하는 양이 3.75배 높음을 확인했고, 선행 연구 결과를 활용하여 연간 국내 도로 환경에서 강우에 의해 환경 구획으로 이동 가능한 타이어 마모입자의 총량은 9,592 ton이며, 이 중 288 ton이 해양 미세플라스틱으로 영향을 줄 수 있다는 연구 결과를 도출했다. 단, 본 연구는 한정적 공간과 예측된 결과란 한계가 있으나, 타이어 마모입자의 저감을 위해서 국내 도로 환경과 하수 처리시스템 개선의 필요성을 언급하고자 한다. 향후 본 연구 결과의 검증을 위해 실제 환경 구획에서 샘플 포집과 타이어 마모입자의 농도 분석 연구를 수행할 계획이다.

• 한국토양비료학회지
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• 제43권3호
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• pp.260-267
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• 2010

As sloped farmland is subject to runoff and soil erosion and consequently require appropriate vegetative coverage to conserve soil and water, a field study was carried out to evaluate the impact of crop canopy coverage on soil loss and runoff from the experimental plot with three different textural types (clay loam, loam, and sandy loam). The runoff and soil loss were examined at lysimeters with 15% slope, 5 m in length, and 2 m in width for five months from May to September 2009 in Suwon ($37^{\circ}$ 16' 42.67" N, $126^{\circ}$ 59' 0.11" E). Red pepper (Capsicum annum L. cv. Daechon) seedlings were transplanted on three different dates, May 4 (RP1), 15 (RP2), and 25 (RP3) to check vegetation coverage. During the experimental period, the vegetation coverage and plant height were measured at 7 day-intervals and then the 'canopy cover subfactor' (an inverse of vegetation cover) was subsequently calculated. After each rainfall ceased, the amounts of soil loss and runoff were measured from each plot. Under rainfall events >100 mm, both soil loss and runoff ratio increased with increasing canopy cover subfactor ($R^2$=0.35, p<0.01, $R^2$=0.09, p<0.1), indicating that as vegetation cover increases, the amount of soil loss and runoff reduces. However, the soil loss and runoff were depending on the soil texture and rainfall intensity (i. e., $EI_{30}$). The red pepper canopy cover subfactor was more highly correlated with soil loss in clay loam ($R^2$=0.83, p<0.001) than in sandy loam ($R^2$=0.48, p<0.05) and loam ($R^2$=0.43, p<0.1) plots. However, the runoff ratio was effectively mitigated by the canopy coverage under the rainfall only with $EI_{30}$<1000 MJ mm $ha^{-1}hr^{-1}$ ($R^2$=0.34, p<0.05). Therefore, this result suggested that soil loss from the red pepper field could be reduced by adjusting seedling transplanting dates, but it was also affected by the various soil textures and $EI_{30}$.

• Asian-Australasian Journal of Animal Sciences
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• 제22권8호
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• pp.1107-1112
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• 2009

The separation of X and Y chromosome-bearing sperm is of use in many aspects of livestock maintenance. In this study, we sought to determine the difference in DNA content between X- and Y-bearing sperm, separate sperm into X- and Y-enriched pools, and assess the efficacy of sorting. Sperm collected from Duroc and miniature pigs were stained with 20.8 $\mu{M}$ Hoechst 33342 and analyzed using a high-speed cell sorter. Measurement of the fluorescence intensity of stained sperm nuclei revealed that the X-bearing sperm of Duroc and miniature pigs respectively contain 2.75% and 2.88% more DNA than Y-bearing sperm. In total, 50.18% of the sperm were assigned to the X-sorted sample and 49.82% was assigned to the Y-sorted sample for Duroc pigs. For miniature pigs, the Xsorted sample represented 50.19% of the population and the Y-sorted represented 49.81% of the population. Duplex PCR was used to evaluate accuracy of sorting. A fast and reliable method for porcine sexing was developed through amplification of the sex-determining region of the Y chromosome gene (SRY). Oligonucleotide primers were designed to amplify the conserved porcine SRY high motility group (HMG) box sequence motif. We found that the primer pair designed in this study was 1.46 times more specific than previously reported primers. Thus, this study shows that the present method can be applied in porcine breeding programs to facilitate manipulation of the sex ratio of offspring and to achieve precise sexing of porcine offspring by amplification of the HMG box of the SRY gene.

• 한방안이비인후피부과학회지
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• 제24권1호
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• pp.121-141
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• 2011

Objective : This Experimental study was done to investigate the Effect of Taklisodok-um and Hwangryunhaedok-tang(TH) on Atopic Dermatitis. Methods : We assessed effects of TH on the IgE, IL-4, IL-5, IL-6, IgM, IgG1, IFN-${\gamma}$ in vivo, on the IL-4, IL-5, CCR3 in the skin tissues of ear and dorsum with NC/Nga mice. And we assessed effects of TH on the COX-2, IL-$1{\beta}$, TNF-${\alpha}$, IL-6 with RAW 264.7 cell. Results and Conclusion : 1. IgE, IL-4, IL-5, IL-6, IgM, IgGl levels in the serum of TH treated NC/Nga mouse group were decreased compared to the untreated control mice. IFN-r showed a increase in the experimental group compared to the untreated control group. The spleen weight of TH treated NC/Nga mice was decreased compared to the untreated control group. 2. mRNA expression levels of IL-4, IL-5 and CCR3 in the skin tissues of TH treated NC/Nga mice were decreased, and expression levels of IL-6 in the skin tissues of TH treated NC/Nga mice were decreased compared to the untreated control group. IFN-${\gamma}$ mRNA expression levels were increased compared to the untreated control group. 3. Judged from that IL-$1{\beta}$, TNF-${\alpha}$, IL-6 express of gene, effect of inflammatory Cytokines revelation were decreased compared to the untreated control group. 4. Depend on the strength of TH, inflammatory RAW 264.7 in the serum of TH were inhibited compared to the untreated control serum that leaded a COX-2 activity model. 5. Histological observation of the ear and skin tissues showed that the extents of inflammation and infiltrated immune cells in the epidermis and dermis of TH treated NC/Nga mice were highly reduced compared to the untreated control group.

• 한국작물학회지
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• 제45권3호
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• pp.151-157
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• 2000

옥수수수염에 함유되어 있는 maysin 및 유사 flavonoid 물질의 분리 및 정제법을 확립하여 신품종 육성의 기초적인 자료를 제공하고자 본 시험을 수행하였으며 얻어진 결과를 요약하면 다음과 같다. 1. Preparative $C_{18}$ 컬럼에서 10% MeOH에 용출된 물질은 neochlorogenic acid, chlorogenic acid 및 4-caffeoylquinic acid였으며 30% MeOH로 용출된 물질은 rhamnosyl isoorientin이었고 maysin은 50%의 MeOH에서 용출되었다. 2. Silicic acid 컬럼으로 maysin 조추출물의 1차 정제시 100% ethyl acetate 500$m\ell$로 컬럼에 흡착되어 있는 maysin을 용출시켰으며, 이때 수거된 maysin의 순도는 75% 이상에 해당하였고, $C_{18}$ 컬럼($\frac{1}{2}$$\times$43")으로 maysin의 2차 정제시 maysin의 순도는 95% 이상에 달하였다. 3. FAB-MS에 의한 maysin의 분자량은 577M＋H m/z이고, fragmentation으로 보아 431M＋H m/z은 rhamnose에 해당하였고, $^1$H 및 $^{13}$C NMR에 의한 spectrum을 확인한 결과 분리한 물질이 maysin임을 확인할 수 있었다. 있었다.