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한우에 있어서 Rosette Inhibition Test 에 의한 조기 임신인자(Early Pregnancy Factor)의 검출
성환후,백광수,고응규,신기준,박용윤,신원집 한국축산학회 1997 한국축산학회지 Vol.39 No.4
Early pregnancy factor(EPF) is one of the pregnancy associated proteins, and it is detected in senun of many pregnant animals shortly after fertilization. The present study was conducted to establish a system of early pregnancy by EPF detection in Hanwoo cows. The EPF activity was measured by the rosette inhibition test on day 15 after artificial insemination or non-insemination. The rate of rosette formation between Hanwoo lymphocytes and sheep red blood cells was significantly(P$lt;0.05) higher compared to that between Hanwoo lymphocytes and goat, or rabbit red blood cells. The rosette formation between lymphocytes suspension and sheep red blood cells with anti-lymphocytes was not significantly(P$lt;0.05) changed until 5∼20 min. of culture, and then decreased dramatically by 30 min. There were significant(P$lt;0.05) differences in the rosette inhibition titer(RIT) between pregnant and non-pregnant Hanwoos on day 15 after artificial insemination. The results indicate that the expression of early pregnancy factor by the rosette inhibition test might be used to diagnosis of early pregnancy in Hanwoo.
Tunable threshold voltage in solution-processed single-walled carbon nanotube thin-film transistors
Seong, N.,Kim, T.,Kim, H.,Ha, T.J.,Hong, Y. Elsevier 2015 Current Applied Physics Vol.15 No.suppl1
We have investigated tunable threshold voltage in solution-processed single-walled carbon nanotube thin-film transistors (SWCNT TFTs) employing a simple and reproducible method of chemical encapsulation. Compared to a pristine one, SWCNT TFTs encapsulated with ammonium hydroxide (NH<SUB>4</SUB>OH) and nitric acid (HNO<SUB>3</SUB>) exhibit a negative shift and a positive shift in threshold voltage, respectively. Such results can be explained by the modification of the energy band at the interface between the source metal electrode and the SWCNT network. By using the Y-function method, we also characterized electrical properties such as field-effect mobility, threshold voltage, and contact resistance for TFTs treated with NH<SUB>4</SUB>OH or HNO<SUB>3</SUB>. The technique to favorably tune threshold voltage in solution-processed SWCNTs is significant for constituting CNT-based nanoelectronics.
Growth of Epitaxial MgB<sub>2</sub> Thick Films with Columnar Structures by Using HPCVD
Seong, W. K.,Huh, J. Y.,Kang, W. N.,Kim, J.-W.,Kwon, Y.-S.,Yang, N.-K.,Park, J.-G. Wiley - VCH 2007 CHEMICAL VAPOR DEPOSITION -WEINHEIM- Vol.13 No.12
<P>Epitaxial MgB<SUB>2</SUB> thick films are grown on Al<SUB>2</SUB>O<SUB>3</SUB> substrates at 600 °C by using the hybrid physical (HP)CVD technique. In order to obtain a high magnesium vapor pressure around the substrates, we use a special susceptor having a susceptor cap and achieve a very high growth rate of 0.17 &mgr;m min<SUP>–1</SUP>. Hexagonal-shaped columnar structures are observed by cross-sectional and planar-view transmission electron microscope (TEM) images. For the 1.7 &mgr;m thick film, the T<SUB>c</SUB> is observed to be 40.5 K with a J<SUB>c</SUB> of 1.5 × 10<SUP>6</SUP> A cm<SUP>–2</SUP> at 30 K. The vortex pinning mechanism by intercolumnar boundaries will be discussed.</P> <B>Graphic Abstract</B> <P>By using novel HPCVD technique with a special susceptor and a susceptor cap, epitaxial MgB<SUB>2</SUB> thick films with columnar structures are successfully fabricated at low temperatures (below 600 °C). The susceptor cap significantly enhances the local magnesium vapor pressure around the substrates so that a very high growth rate of 0.17 &mgr;m/min could be achieved. For the 1.7-&mgr;m-thick film, the T<SUB>c</SUB> was observed to be 40.5 K.</P>
Ranot, M.,Seong, W.K.,Jung, S.G.,Lee, N.H.,Kang, W.N.,Joo, J.H.,Zhao, Y.,Dou, S.X. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15
We report on Ag and Cu doping in MgB<SUB>2</SUB> thick films using amorphous Ag- and Cu-impurity layers with various thicknesses, 4, 8, 16, and 32nm. Firstly, Ag- and Cu-impurity layers were deposited on Al<SUB>2</SUB>O<SUB>3</SUB>(0001) substrates at room temperature by using pulsed laser deposition system. Subsequently MgB<SUB>2</SUB> films were grown on the top of Ag or Cu/Al<SUB>2</SUB>O<SUB>3</SUB> substrates at 560 and 600<SUP>o</SUP>C by using hybrid physical-chemical vapor deposition. The effect of Ag and Cu doping as well as growth temperature on the microstructure and critical current density (J<SUB>c</SUB>) of MgB<SUB>2</SUB> films were investigated. It was found that both of Ag/Cu doping and low growth temperature can significantly enhance J<SUB>c</SUB> without suppression of T<SUB>c</SUB>. The increase in J<SUB>c</SUB> results from improved grain connectivity and strong flux pinning by high density of grain boundaries and other types of defects introduced by Ag- or Cu-impurity layers.
Effect of grain-boundary flux pinning in MgB<sub>2</sub> with columnar structure
Kim, D.H.,Hwang, T.J.,Cha, Y.J.,Seong, W.K.,Kang, W.N. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15
We studied the flux pinning properties by grain boundaries in MgB<SUB>2</SUB> films prepared by using a hybrid physical chemical vapor deposition method on the c-axis oriented sapphire substrates. All the films we report here had the columnar grains with the growth direction perpendicular to the substrates and the grain sizes in the range of a few hundred nanometers. At very low magnetic fields, no discernable grain-boundary (GB) pinning effect was observed in all measuring temperatures, but above those fields, the effect of GB flux pinning was observed as enhanced critical current densities (J<SUB>c</SUB>s) and reduced resistances when an external magnetic field (B) was aligned parallel to the c-axis. We interpret the B dependence of J<SUB>c</SUB> in the terms of flux line lattice shear inside the columnar grains activated by dislocations of Frank-Read source while the flux lines pinned by GB act as anchors for dislocations. Magnetic field dependence of flux pinning force density for B parallel to the c-axis was reasonably explained by the above model.
Effects of oxide coating on the growth of single grain YBCO bulk superconductors
Park, S.D.,Jun, B.H.,Park, B.J.,Jung, S.Y.,Seong, B.S.,Kim, C.J. North-Holland 2009 Physica. C, Superconductivity Vol.469 No.15
Surface oxide coating and bottom inserting of oxide plates have been conducted to top seeded melt growth (TSMG) processed YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-y</SUB> (Y123) bulk superconductors with an aim of controlling the Y123 nucleation and growth. The coating medium for surfaces was Yb<SUB>2</SUB>O<SUB>3</SUB> solution and the bottom inserts were Yb<SUB>2</SUB>O<SUB>3</SUB>/Y<SUB>2</SUB>O<SUB>3</SUB> powder compact. Many vertical cracks were found to develop at the compact/insert interfaces when an Yb<SUB>2</SUB>O<SUB>3</SUB> insert was used, but the crack evolution was greatly reduced when a (Yb<SUB>2</SUB>O<SUB>3</SUB>+Y<SUB>2</SUB>O<SUB>3</SUB>) insert was used. The formation of the vertical cracks is ascribed to the difference in thermal expansion between the YBCO compact and bottom insert. Presence of vertical cracks was found to be crucial to the trapped magnetic field and levitation forces of single grain YBCO bulk superconductors. The Y123 nucleation and growth in TSMG-processed YBCO bulk superconductors were successfully controlled by conducting surface coating and bottom plating using a (Yb<SUB>2</SUB>O<SUB>3</SUB>+Y<SUB>2</SUB>O<SUB>3</SUB>) insert and as a result, the levitation properties were much enhanced.