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Microstructure evolution of rare earth Pr modified alumina-silicate short fiber-reinforced Al-Si metal matrix composites

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Rare Metals 2009年第2期28卷 164-168页

作者： Peng Jihua Li Wenfang Huang Fangliang Tian jun liu gang Du jun S China Univ Technol Sch Mat Sci & Engn Guangzhou 510640 Guangdong Peoples R China

Al-Si metal matrix composites (MMCs) reinforced with 20 vol.% alumina-silicate shot fibers (Al2O3-SiO2(sf)) were fabricated by an infiltration squeeze method. Pure Pr metal was added into these composites. The effect of Pr addition on the microstructure evolution of Al-Si MMCs was investigated by SEM,TEM,and EDS. Pr addition is favorable to make uniform microstructures with the modified eutectic Si crystal. PrAlSi phase with high contents of Pr and Si is observed on the interface between the fiber and the m...

关键词： metal matrix composite microstructure evolution microscope Al-Si alloys rare earth

The metastable constituent effects on size-dependent deformation behavior of nanolaminated micropillars: Cu/FeCoCrNi vs Cu/CuZr

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Journal of Materials Science & Technology 2021年第9期68卷 16-29页

作者： Yufang Zhao Jinyu Zhang YaQiang Wang Shenghua Wu Xiaoqing Liang Kai Wu gang liu jun Sun State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an710049China

Metastable high entropy alloys(HEAs) and amorphous metallic glasses(MGs), with the chemical disordered character, are intensively studied due to their excellent performance. Here, we introduce Cu to separately constrain these two metastable materials and comparatively investigate their deformation behaviors and mechanical properties of Cu/HEA Fe Co Cr Ni and Cu/MG Cu Zr nanolaminated micropillars in terms of intrinsic layer thickness h and extrinsic pillar diameter D. The metastable HEA layers, as the hard phase in Cu/HEA micropillars, are stable and dominate the deformation, while transformation(crystallization) occurs in MG which plays a minor role in deformation of Cu/MG micropillars. The h-controlled deformation mode transits from the D-independent homogenous-like deformation at large h to the Ddependent shear banding at small h in both Cu/HEA and Cu/MG micropillars. Although both Cu/HEA and Cu/MG micropillars exhibit a maximum strain hardening capability controlled by h, the former manifests much lower hardening capability compared with the latter. The intrinsic size h and extrinsic size D have a strong coupling effect on the strength of Cu/HEA and Cu/MG micropillars. The strength of strength of Cu/HEA micropillars exhibits the D-dependent transition from "smaller is stronger" to "smaller is weaker"with increasing h. By contrast, the strength of Cu/MG micropillars exhibits the transition from bulk-like D-independent behavior at large h to small volume D-dependent behavior(smaller is stronger) at small h.

关键词： High-entropy alloys Metallic glasses Nanolaminated micropillars Size effect

Asymmetric synthesis of pedamide using I_2-induced heterocyclization to construct the skeleton

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Chinese Chemical Letters 2009年第7期20卷 775-778页

作者： De gang liu Ji jun Xue Zhi Xiang Xie Li Ping Wei Hua Bing Zhang Ying Li State Key Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 PR China

An alternative approach to synthesize pedamide, a key building block of pederin was described. Iodine-induced asymmetric heterocyclization was used as the key step to construct the skeleton, a tetrahydropyran ring with three chiral centers. Brown＇s asymmetric allylation and Lewis acid-mediated allylation were investigated to introduce chains and chiral alcohols. Sharpless dihydroxylation decorated the side chain. And high optically pure target was obtained by removing the epimers formed in these reactions on column chromatography.C2009 Ji jun Xue. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All fights reserved.

关键词： Synthesis Pedamide Pederin

Identification of a Novel Gene SRG4 Expressed at Specific Stages of Mouse Spermatogenesis

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Acta Biochimica et Biophysica Sinica 2004年第5期36卷 351-359页

作者： Xiao-Wei XING, Lu-Yun LI, gang liu, jun-Jiang FU, Xiao-jun TAN, and Guang-Xiu LU* Human Reproduction and Stem Cell Engineering Institute, Central South University, Changsha 410078, China Human Reproduction and Stem Cell Engineering Institute Central South University

Spermatogenesis is a complex process. Two spermatocytes expression sequence tags (ESTs) BG101130 and BG100990 were found. Their putative amino acid sequences have high homology with rat Spag4 (sperm antigen 4). By electrical hybridization, a novel cDNA encoding polypeptide of 348 amino acid residues was identified from a mouse testis cDNA library. The new gene was designated as SRG4 (Spermatogenesis related gene 4) (GenBank accession No. AY307077). Results of Northern blot and RT- PCR revealed that SRG4 expressed specifically in mouse testis. Changes of SRG4 expression in mouse dif- ferent development stages were observed by RT-PCR. The SRG4 mRNA was hardly detected in 2 weeks postpartum, and expressed abundantly from 3 weeks later, reaching top lever at 4–5 weeks, while slightly down in aging mouse testis. Results of in situ hybridization showed that SRG4 gene expressed abundantly in spermatocytes, round spermatids. This indicated SRG4 gene may play an important role in mouse meiotic divisions of spermatocytes.

关键词： gene cloning testis tissues expression pattern in situ hybridization spermatogenesis

A Framework of Environmental Modelling and Information Sharing for Urban Air Pollution Control and Management

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Journal of China University of Mining and Technology 2007年第2期17卷 172-178页

作者： liu gang-jun FU Er-jiang WANG Yun-jia ZHANG Ke-fei HAN Bao-ping ARROWSMITH Colin School of Mathematical and Geospatial Science RMIT University Melbourne Victoria 3000 Australia School of Environment Science and Spatial Informatics China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

More effective environmental pollution control and management are needed due to the increasing environ-mental impacts from a range of human activities and the growing public demands for a better living environment. Urban air pollution is a serious environmental issue that poses adverse impacts on the health of people and the environment in most metropolitan areas. In this paper,we propose a geoinformatics augmented framework of environmental modelling and information sharing for supporting effective urban air pollution control and management. This framework is out-lined in terms of its key components and processes including: 1) an integrated,adaptive network of sensors for envi-ronmental monitoring; 2) a set of distributed,interoperable databases for data management; 3) a set of intelligent,robust algorithms and models for environmental modelling; 4) a set of flexible,efficient user interfaces for data access and in-formation sharing; and 5) a reliable,high capacity,high performance computing and communication infrastructure for integrating and supporting other framework components and processes.

关键词： environmental modelling information sharing urban air pollution geoinformatics

Land subsidence induced by groundwater extraction and building damage level assessment—a case study of Datun, China

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Journal of China University of Mining and Technology 2008年第4期18卷 556-560页

作者： FENG Qi-yan liu gang-jun MENG Lei FU Er-jiang ZHANG Hai-rong ZHANG Ke-fei Jiangsu Key Laboratory of Resources and Environmental Information Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China School of Mathematical ＆ Geospatial Sciences Royal Melbourne Institute of Technology University Melbourne 3001 Australia

As in many parts of the world, long-term excessive extraction of groundwater has caused significant land-surface sub- sidence in the residential areas of Datun coal mining district in East China. The recorded maximum level of subsidence in the area since 1976 to 2006 is 863 mm, and the area with an accumulative subsidence more than 200 mm has reached 33.1 km2 by the end of 2006. Over ten cases of building crack due to ground subsidence have already been observed. Spatial variation in ground subsi- dence often leads to a corresponding pattern of ground deformation. Buildings and underground infrastructures have been under a higher risk of damage in locations with greater differential ground deformation. Governmental guideline in China classifies build- ing damages into four different levels, based on the observable measures such as the width of wall crack, the degree of door and window deformation, the degree of wall inclination and the degree of structural destruction. Building damage level (BDL) is esti- mated by means of ground deformation analysis in terms of variations in slope gradient and curvature. Ground deformation analysis in terms of variations in slope gradient has shown that the areas of BDL III and BDL II sites account for about 0.013 km2 and 0.284 km2 respectively in 2006, and the predicted areas of BDL (define this first) III and II sites will be about 0.029 km2 and 0.423 km2 respectively by 2010. The situation is getting worse as subsidence continues. That calls for effective strategies for subsidence miti- gation and damage reduction, in terms of sustainable groundwater extraction, enhanced monitoring and the establishment of early warning systems.

关键词： land subsidence groundwater extraction ground deformation slope gradient building damage level Datun China

Molecular Characterization and Expression Pattern of Rheb Gene in Inner Mongolia Cashmere Goat(Capra hircus)

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Agricultural Sciences in China 2011年第9期10卷 1452-1458页

作者： ZHENG Xu YANG Jiao-fu WANG Xiao-jing LIANG Yan WU Man-lin SHI Jie-jun ZHANG Tao QIN Yin LI Shu-yu HAO Xi-yan WANG Zhi-gang liu Dong-jun College of Life Science lnner Mongolia University/Key Laboratory of Mammal Reproductive Biology and Biotechnology Ministry of Education Hohhot 010021 P.R.China

As one member of the Ras super family, Rheb is an upstream regulator of mTOR signaling pathway, which regulates the process of cell-growth, proliferation and differentiation. In order to study the relationship between Rheb and mTOR in Inner Mongolian Cashmere goat （Capra hircus） cells, Ras homolog enriched in brain （Rheb） gene eDNA was amplified by RT-PCR. It is 555 bp in length and includes the complete ORF encoding 184 amino acids （GenBank accession no. HM569224）. The full eDNA nucleotide sequence has a 99% identity with that of sheep, 98% with cattle and 93% with human while their amino acids sequence shares identity with 98, 97 and 97% of them, correspondingly. The bioinformatics analysis showed that Rheb has a Ras family domain, two casein kinase II phosphorylation sites, two ATP/GTP-binding sites motifA （P-loop）, a prenyl group binding site （CAAX box）. Tissue-specific expression analysis performed by semi- quantitative RT-PCR. The Rheb gene was expressed in all the tested tissues and the highest level ofmRNA accumulation was detected in brain, suggesting that Rheb played an important role in goat cells.

关键词： Inner Mongolia Cashmere goat Rheb gene expression pattern

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新时期高校体育教育改革的模式创新

成都体育学院学报 2009年第5期35卷 88-90页

作者：刘钢军内蒙古科技大学体育部内蒙古包头014010

我国高校体育教育改革关系到当代大学生的健康成长和终身体育思想的确立。文章从高校体育教育改革的理念、目标、模式等方面进行初步探索。

关键词：高校体育改革与创新终身体育素质教育

cDNA Cloning of Goat DNA Methyltransferase 1,Screening of shRNA Vectors and Influences to Development of Nuclear Transfer Embryos

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Agricultural Sciences in China 2010年第7期9卷 1035-1040页

作者： LAN Jie,SONG Yong-li,HUA Song,liu Yong-gang,liu jun,ZHANG Hai-lin and ZHANG Yong Key Laboratory of Animal Reproductive Physiology & Embryo Technology,Institution of Biotechnology,College of Veterinary Medicine,Northwest A&F University,Yangling 712100,P.R.China [a] Key Laboratory of Animal Reproductive Physiology & Embryo Technology Institution of Biotechnology College of Veterinary Medicine Northwest A&F University Yangling 712100 P.R. China

This study was designed to clone cDNA of goat DNA methyltransferase 1（DNMT1） gene,to screen an effective shRNAproducing vector targeting goat DNA methyltransferase 1 and to improve the developmental competence of goat nuclear transfer embryos by decreasing the DNMT1 expression in donor *** this study,PCR primers were designed against regions of high homology between bovine and sheep sequences and then used to amplify the larger portions of the coding ***,3 RNAi oligonucleotides were designed based on the cloned sequences and inserted into pRNAT-U6.1/Neo vector,acquiring 3 new vectors,respectively termed pRNAD1,pRNAD2 and *** the positive cells were sorted by flow cytometry after transfection and detected by real-time PCR analysis and sodium bisulfite genomic ***,the developmental rates of nuclear transfer（NT） embryos generated using donor cells with and without the effective shRNA vector respectively,as well as in vitro fertilization（IVF） embryos were observed and *** results showed that the coding regions of goat DNA methyltransferase 1 gene was successfully cloned（GenBank ***617538）.Furthermore,an effective interfering shRNA（pRNAD2） was obtained,with its interference effect being 47.88%.Finally,NT embryos with shRNA vector harbored better developmental competence during morula and blastocyst stage compared to controls（P 〈 0.05）,reaching the similar rates to IVF embryos（P 〉 0.05）.In conclusion,goat DNA methyltransferase 1 gene cDNA was cloned and sequenced,an effective shRNA vector responsible for inhibiting DNA methyltransferase 1 expression was developed and the developmental competence of goat nuclear transfer morulae and blastcysts was significantly improved,which provided a feasible pathway for improving goat nuclear transfer embryo development competence by decreasing the methylation level in donor cells through RNAi-mediated manner.

关键词： cDNA DNA methyltransferase 1 goat methylation shRNA