http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Zi-Li Lin,Ying-Hua Li,Yong-Nan Xu,Suk Namgoong,Xiang-Shun Cui,Nam-Hyung Kim 한국동물생명공학회(구 한국동물번식학회) 2013 Reproductive & Developmental Biology(Supplement) Vol.37 No.2s
Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are members of the transforming growth factor β (TGF-β) family, and their roles in oocyte maturation and cumulus expansion are well known in the mouse and human, but not in the pig. We investigated GDF9 and BMP15 expression in porcine oocytes during in vitro maturation. A significant increase in the mRNA levels of GDF9 and BMP15 was observed at germinal vesicle breakdown, with expression levels peaking at metaphase I (MI) but decreasing at metaphase II (MII). GDF9 and BMP15 protein localized to the oocyte cytoplasm. While treatment with GDF9 and BMP15 increased cumulus expansion and the expression of genes involved in both oocyte maturation (c-mos, cyclinb1, and cdc2) and cumulus expansion (has2, ptgs2, ptx3, and tnfaip6). SB431542 (a TGFβ–GDF9 inhibitor) decreased meiotic maturation at MII. Following parthenogenetic activation, the percentage of blastocysts in SB431542 treatment was lower than in the control (74.4% and 41.3%, respectively). Treatment with GDF9 and BMP15 also increased the mRNA levels of maternal genes such as c-mos (a regulatory subunit of mitogen-activated protein kinase (MAPK)), and cyclinb1 and cdc2 (regulatory subunits of maturation/M phase promoting factor (MPF)); however, SB431-542 significantly decreased their mRNA levels. These data were supported by poly (A)-test PCR and protein activity analyses. Our results show that GDF9 and BMP15 function in cumulus expansion and that they stimulate MPF and MAPK activity in porcine oocytes during in vitro maturation.
Current situation and future prospects for beef production in China - A review
Li, Xiang Zi,Yan, Chang Guo,Zan, Lin Sen Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.7
The beef industry is an important part of livestock and meat production in China. China ranks third in the world for beef production. With the rapid development of the Chinese economy, beef consumption has grown rapidly, and beef consumption has been increasing with rising per capita gross domestic production. However, the domestic beef industry in China has not been able to keep pace with growth in consumption, making China a net importer of beef from other countries. Moreover, the volume of production has increased little despite rising demand. The slowing of growth in beef production in recent years has led to a sharp rise in beef prices. Domestic beef production and consumption is restricted by a shortage of beef cattle inventory. The Chinese beef industry is facing many technical problems including transformation of traditional practices, feeding and management systems, and genetic improvement of cattle breeds. The long-term, sustainable development of the Chinese beef industry is an important issue for China.
Properties of an AlGaN/AlN Distributed-Bragg-reflector Structure
Li-Li Zhang,Zhan-Hui Liu,Xiao-Gu Huang,Qing-Fang Li,Rong Zhang,Zi-Li Xie,Xiang-Qian Xiu 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7
An AlGaN/AlN distributed-Bragg-reflector (DBR) structure with a high Al content was grown byusing plasma-assisted molecular beam epitaxy (PA-MBE). The properties of the sample were characterizedby using the transmission electron microscopy, high-resolution X-ray diffraction, atomicforce microscopy, and reflectivity spectrum measurements. The reciprocal space mapping analysisindicated that the strain in the AlGaN layers was partially relaxed. The morphology of the DBRexhibited a surface covered by grains (average size of about 130 nm), and the surface roughness wasabout 2 nm. The spectral measurements showed that the DBR structure presented a peak reflectivityof 68.8% at the center wavelength of 247 nm, which indicated that this DBR structure couldwork in the deep solar-blind UV region with acceptable reflectivity. However, the optical propertiesof the DBR structure were deteriorated by the fluctuation of the Al composition, non-uniformity ofthe layer thickness, the blurry, rough interface in the DBR structure, and so on.
Properties of a CdZnO/ZnO Multiple Quantum-Well Light-Emitting Diode
Zhan-Hui Liu,Li-Li Zhang,Qing-Fang Li,Rong Zhang,Zi-Li Xie,Xiang-Qian Xiu,Bin Liu 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.7
A CdZnO/ZnO multiple quantum-well light-emitting diode (LED) structure was successfully grown by using plasma-assisted molecular beam epitaxy on a p-GaN template that had been grown by using metal-organic chemical-vapor deposition on a c-sapphire substrate. The properties of the sample were characterized by using high-resolution X-ray diffraction, transmission electron microscopy, and temperature-dependent photoluminescence measurements. The light output performance of the CdZnO/ZnO QW LED device was also investigated in detail by using I-V and electroluminescence spectral measurements. The characterization showed that our CdZnO/ZnO QW LED structure had good crystalline quality and weaker carrier localization. Owing to the heterojunction structure, the I-V curve indicated that the LED device had a higher turn-on voltage and series resistance. The EL measurement demonstrated that for our LED device’s optoelectronic characteristic, the carrier-screening effect played the dominant role in the emission-energy blue-shift mechanism, and the broadening of the emission energy width was mainly ascribed to the band-filling effect. Without a special heat sinking, the L-I curve exhibited slight efficiency droop after 30 mA.
Li Zhuan,Xiao Peng,Zhu Zi-bing,Xiong Xiang 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.3
Carbon fibre reinforced carbon and silicon carbide dual matrix composites (C/C-SiC) are a new type of high performance brake materials. In the present study, C/C-SiC brake composites were fabricated by the combination of chemical vapor infiltration (CVI) with liquid silicon infiltration (LSI). Results show the composite is composed of 55%C, 39% β-SiC, and 6%Si. There exist two different areas of SiC, one zone of coarse micro-β-SiC grains between 5 and 20 μm at the SiC/silicon interface, and this zone usually forms inside the porosity of the carbon fibre reinforced carbon (C/C) preform such as around the fibres and among the C/C bundles. The other zone consists of fine nano-SiC particles with dimensions of 100-800 nm at the pyrocarbon/carbon fibre interface. From these observations, reaction mechanisms governing the siliconization of porous C/C preform are proposed. After an initial reaction of carbon with liquid silicon, an initial continuous SiC layer formed on the silicon/pyrocarbon interface, and the subsequent formation of SiC is controlled by diffusion of carbon atoms and/or silicon atoms through the already formed SiC layer.
( Zi-jiang Li ),( Shilin Chen ),( Xiang-hao Yang ),( Rui Wang ),( Hee-jeong Min ),( Lei Wu ),( Chuan-ling Si ),( Young-soo Bae ) 한국목재공학회 2018 목재공학 Vol.46 No.2
Juglans mandshurica is a fast growing hard species, which is a tree in family of Juglandaceae and has a wide distribution in China, Korea and eastern Russia. Plant materials from J. mandshurica have extensively been used in folk medicines to prevent or cure gastric, esophageal, lung and cardiac cancer. As one chain of our searching for anticomplementary agents from natural sources, two epimeric ellagitannins, [2,3-O-4,4′,5,5′,6,6′,-hexahydroxydiphenoyl (HHDP))-(α,β)-D-glucose] (I) and pedunculagin (II) were purified from 70% acetone extracts of the stem barks of J. mandshurica by Thin Layer Chromatography and Sephadex LH-20 column chromatography approaches. The chemical structures of the isolated compounds were characterized by MS, NMR, and a careful comparation with published literatures. The epimeric ellagitannins I and II exhibited inhibitory properties against a classical pathway of complementary system with 50 % inhibitory concentrations (IC<sub>50</sub>) values of 65.3 and 47.7 μM, respectively, comparing with riliroside (IC<sub>50</sub>=104 μM) and rosmarinic acid (IC<sub>50</sub>=182 μM), which were used as positive controls. Thus, the work indicated both the two secondary metabolites possess excellent inhibitory activity and might be developed as potential anticomplementary chemicals.
Evaluation on Dry Sliding Wear Behavior of (TiB+TiC)/Ti- 6Al-4V Matrix Composite
Zi-Run Yang,Hai-Xiang Huan,Cui-Feng Jiang,Wen-Min Li,Xue-Ran Liu,류성기 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.8
The dry sliding wear tests were performed for 10 vol.% (TiB+TiC)/Ti-6Al-4V matrix composites at various test conditions. The morphology and phases of worn surfaces and cross-sectional surfaces were investigated by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The wear loss of composites with the increase of load, but the wear behavior got more complex when the sliding speed and ambient temperature got higher. Low wear loss was achieved at lower sliding speed with higher temperature or higher sliding speed with lower temperature. A tribo-layer was always formed on worn surface during testing. It possessed different features and thus presented different effects during sliding wear. Meanwhile, the TiB and TiC particulates strengthened the Ti-6Al- 4V matrix, which increased the thermal stability of composites and postponed the occurrence of severe plastic deformation. In the mild wear region, those particulates could directly resist wear by reducing adhesive wear. In the steady stage, fractured TiB and TiC particulates participated in forming the tribo-layer together with wear debris, which effectively hindered the plastic deformation and thermal softening of the matrix. Experiment results suggest that the existence of different characteristic tribo-layers would result in the variation of wear behavior.