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Critical mechanical properties and FEA simulation for crashworthiness assessment of a coarse-grained cast AM50 alloy

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Journal of Magnesium and Alloys 2015年第3期3卷 188-196页

作者： s.xu C.H.M.simha M.Gesing J.Liang J.Lo CanmetMATERIALs Natural Resources Canada183 Longwood Rd SHamiltonOntario L8P 0A5Canada

A coarse-grained AM50 alloy was used as a model alloy for investigation of constitutive behaviour,Charpy toughness and effect of stress state on deformation and failure of cast Mg *** results provide critical mechanical properties of a cast AM50 alloy for crashworthiness assessment and development of finite element simulation *** cast Mg alloys,the effect of strain rate and temperature is larger on tensile strength than on compressive strength because twinning is more extensive in compression than in *** effect of strain rate on compressive strength is negligible because twinning activity of the cast Mg alloy is *** load *** of Charpy specimens were measured for modelling,and the effect of loading rate and temperature on load of Charpy specimens is very small because part of the specimen is in *** equivalent strain to fracture of the cylindrical round notched tension specimen decreases with increasing stress triaxiality;though for the flat-grooved plane strain specimen,the equivalent fracture strain remains constant over the range of stress triaxiality *** the two different specimen geometries give rise to different Lode angle values,the test results show that the Lode angle parameter is an important parameter for deformation and fracture of Mg *** element simulations of loading of the cylindrical notched-tension and Charpy specimens were carried out using a Lode-angle dependent von Mises model,and were found to provide a reasonable description of the load-displacement curves measured in the *** the flat-grooved plane strain specimens,the computations under-predicted the force-displacement response measured.

关键词： Effect of strain rate and temperature Tensile and compressive Crash simulation AM50

Molecular Cytogenetic Characterization and stem Rust Resistance of Five Wheat-Thinopyrum ponticum Partial Amphiploids

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Journal of Genetics and Genomics 2014年第11期41卷 591-599页

作者： Qi Zheng Zhenling Lv Zhixia Niu Bin Li Hongwei Li steven s.xu Fangpu Han Zhensheng Li state Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental BiologyChinese Academy of Sciences United states Department of Agriculture Agricultural Research ServiceCereal Crops Research Unit

Partial amphiploids created by crossing common wheat （Triticum aestivum L.） and Thinopyrum ponticum （Podp.） Barkworth ＆ D. R. Dewey are important intermediates in wheat breeding because of their resistance to major wheat diseases. In this study, we examined the chromosome compositions of five Xiaoyan-series wheat-Th, ponticum partial amphiploids （Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430, and Xiaoyan 7631） using GIsH, multicolor-GIsH, and multicolor-FIsH. We found several chromosome changes in these lines. For example, wheat chromosomes 1B and 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively, while wheat chromosome 6B was eliminated from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interspecific translocation involving chromosome 4D and some intergenomic translocations, such as A--B and A--D translocations, among wheat genomes. Analysis of the Th. ponticum chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. We also evaluated these partial amphiploids for resistance to nine races of stem rust, including TTKsK （commonly known as Ug99）. Three lines, Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430, exhibited excellent resistance to all nine races, and could therefore be valuable sources of stem rust resistance in wheat breeding.

关键词： Thinopyrum ponticum Triticum aestivum Partial amphiploid Multicolor-genomic in situ hybridization (mc-GIsH) Multicolor-fluorescent insitu hybridization (me-FIsH) stem rust

Elimination of the yellow pigment gene PsY-E2 tightly linked to the Fusarium head blight resistance gene Fhb7 from Thinopyrum ponticum

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The Crop Journal 2023年第3期11卷 957-962页

作者： xuefeng Li Dong Li Yu xuan Ziming He Lanfei Zhao Yongchao Hao Wenyang Ge shoushen xu Bingqian Hou Biao Wang Jun Guo Wenwen Liu Mingzhu Li Yi Han Cunyao Bo Yinguang Bao Zengjun Qi steven s.xu Guihua Bai Hongwei Wang Lingrang Kong state Key Laboratory of Crop Biology Shandong Key Laboratory of Crop BiologyCollege of AgronomyShandong Agricultural UniversityTai’an 271018ShandongChina state Key Laboratory of Crop Genetics and Germplasm Enhancement Nanjing Agricultural UniversityNanjing 210095JiangsuChina Department of Agronomy Kansas State University2004 Throckmorton HallManhattanKS 66506USA Crop Research Institute Shandong Academy of Agricultural SciencesJinan 250100ShandongChina Cereal Crops Research Unit Red River Valley Agricultural Research CenterUSDA-ARSFargoND 58102USA UsDA Hard Winter Wheat Genetics Research Unit4008 Throckmorton HallManhattanKS 66506USA

Fhb7 is a major gene that was transferred from Thinopyrum ponticum to chromosome 7D of wheat(Triticum aestivum)and confers resistance to both Fusarium head blight(FHB)and Fusarium crown rot(FCR).However,Fhb7 is tightly linked to the PsY-E2 gene,which causes yellow flour,limiting its application in *** break this linkage,marker K-PsY was developed for tagging PsY-E2 and used with Fhb7 markers to identify recombination between the two *** 21,000 BC1F2 backcross progeny(Chinese spring ph1bph1b*2/sDAU 2028)revealed two Fhb7^(+)wheat-Tp7el_(2)L lines,shannong 2–16and shannong 16–1,that carry a desired truncated Fhb7^(+)translocation segment without *** two lines show levels of resistance to FHB and FCR similar to those of the original translocation line sDAU 2028,but have white *** facilitate Fhb7 use in wheat breeding,sTs markers were developed and used to isolate Fhb7 on a truncated Tp7el_(2) translocation ***-isogenic lines carrying the Fhb7^(+)segment were generated in the backgrounds of three commercial cultivars,and Fhb7^(+)lines showed increased FHB and FCR resistance without yield *** breakage of the tight linkage between Fhb7 and PsY-E2 via homoeologous recombination provides genetic resources for improvement of wheat resistance to FHB and FCR and permit the large-scale deployment of Fhb7 in breeding using marker-assisted selection.

关键词： Triticum aestivum Thinopyrum ponticum Fusarium head blight Fusarium crown rot Truncated Fhb7 translocation

Excellent strength-ductility combination in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)Ti_(4)Mo_(1)multi-principal element alloys by dual-morphology B2 precipitates strengthening

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Journal of Materials science & Technology 2023年第3期134卷 60-66页

作者： X.s.Liu R.Li X.F.Fan Q.Q.Liu X.Tong A.X.Li s.xu H.Yang s.B.Yu M.H.Jiang C.Huo P.F.Yu M.T.Dove G.Li state Key Laboratory of Metastable Materials science and Technology Yanshan UniversityQinhuangdao 066004China College of Computer science Sichuan UniversityChengdu 610065China school of Physical and Chemical sciences Queen Mary University of LondonMile End RoadLondon E14NSUnited Kingdom school of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China

Precipitation strengthening provides one of the most widely-used mechanisms for strengthen-ing multi-principal-element alloys(MPEAs).Here,we report dual-morphology B2 precipitates in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)Ti_(4)Mo_(1)MPEA obtained by thermo-mechanical *** microscopy charac-terization reveals that the dual-morphology B2 precipitates are either recrystallized B2 particles formed at the grain boundaries or triple junctions with recrystallization process,or rod-like within the non-recrystallized FCC *** dual-morphology B2 precipitates enhance the yield strength and ultimate tensile strength up to 1120 MPa and 1480 MPa,*** work suggests the mechanical proper-ties of the alloy can be optimized by B2 precipitation strengthening to meet the needs of engineering applications.

关键词： Multi-principal element alloys B2 precipitates Heterogeneous nucleation Precipitation strengthening

Variation in Chromosome Constitution of the Xiaoyan series Partial Amphiploids and Its Relationship to stripe Rust and stem Rust Resistance

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Journal of Genetics and Genomics 2015年第11期42卷 657-660页

作者： Qi Zheng Qiaoling Luo Zhixia Niu Hongwei Li Bin Li steven s.xu Zhensheng Li state Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental BiologyChinese Academy of Science Department of Plant sciences North Dakota State University

The wild relatives of wheat （Triticum aestivum L.） contain tremendous amounts of potentially useful genes and represent a promising source of genetic diversity for wheat improvement （Bommineni and Jauhar, 1997）. Thinopyrum ponticum （Popd.） Barkworth and D. R. Dewey [syn. Agropyron elongatum （Host） P. Beauv., Elytrigia pontica （Podp.） Holub, Lophopy- rum ponticum （Podp.） A. L6ve] （2n = 10x = 70）, has high crossability with various Triticum species. Numerous studies have shown that Th. ponticum carries many potentially valu- able resistance genes against biotic and abiotic stresses （shannon, 1978; Cox, 1991; Zheng et al., 2014a,b）. Transferring the useful genes from Th. ponticum to common wheat through chromosome engineering had been a successful way to enhance the resistance of wheat to pests and diseases （sharma et al., 1989; McIntosh, 1991）.

关键词： Th Variation in Chromosome Constitution of the Xiaoyan series Partial Amphiploids and Its Relationship to stripe Rust and stem Rust Resistance FIsH GIsH IT

Dependence of flow strength and deformation mechanisms in common wrought and die cast magnesium alloys on orientation,strain rate and temperature

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Journal of Magnesium and Alloys 2013年第4期1卷 275-282页

作者： s.xu W.R.Tyson R.Eagleson R.Zavadil Z.Liu P.-L.Mao C.-Y.Wang s.I.Hill A.A.Luo CanmetMATERIALs Natural Resources Canada183 Longwood Road SouthHamiltonON L8P 0A1Canada school of Material science and Engineering Shenyang University of Technology111 Shenliao West RoadShenyang 110870PR China University of Dayton Research Institute 300 College ParkDaytonOH 45469-0133USA General Motors Research&Development Center WarrenMI 48090USA

The controlling plastic deformation mechanisms(*** or twinning)and the structural crash performance of Mg alloys are strongly influenced by loading mode,texture and *** paper summarizes the main results from an experimental program to assess these effects for commercial Mg alloy extrusions(AM30 and AZ31),sheet(AZ31),and high pressure die castings(HPDC,AM50 and AM60).Uniaxial tensile and compressive tests were performed over a wide range of strain rate and temperature(i.e.0.00075–2800 s^(−1) and 100℃ to−150℃)using conventional servo-hydraulic and high-strain-rate universal test machines and a split-Hopkinson-bar(sHB)*** primarily-slip-dominant deformation,the true stress–strain curves showed approximate power-law behavior,and the effects of strain rate and temperature on yield strength could be approximately described by constitutive equations linearly dependent on the rate parameter,Tln(5.3×10^(7)/ɛ˙)where T is test temperature in Kelvin andɛ˙is strain rate in s^(−1).In primarily-twin-dominant deformation,the effects of strain rate and temperature on yield and initial flow stress were negligible or small from quasi-static to 2800 s^(−1) owing to the athermal characteristics of mechanical twinning;the effects may become more pronounced with exhaustion of twinning and increasing proportion of slip.

关键词： Constitutive equation Effects of strain rate and temperature Effects of orientation Crashworthiness Magnesium alloy

偃麦草属植物的染色体倍性变异及秆锈病抗性分析

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偃麦草属植物的染色体倍性变异及秆锈病抗性分析

AlN/s i(100)上CVD siC薄膜的光致发光谱

第六届全国小麦基因组学及分子育种大会

作者：郑琪 Daryl L.Klindworth 李振声 steven s.xu 中国科学院遗传与发育生物学研究所 United states Department of Agriculture Agricultural Research ServiceCereal Crops Research Unit

偃麦草属植物携带许多抗病基因,是小麦抗秆锈病的重要来源。同时,它的染色体倍性水平变异广泛,类型十分丰富。为了鉴定偃麦草属植物的倍性水平,开发新的抗秆锈病基因,我们对207个来源于5个不同种的偃麦草属品系进行了染色体数目检测及... 详细信息

偃麦草属植物携带许多抗病基因,是小麦抗秆锈病的重要来源。同时,它的染色体倍性水平变异广泛,类型十分丰富。为了鉴定偃麦草属植物的倍性水平,开发新的抗秆锈病基因,我们对207个来源于5个不同种的偃麦草属品系进行了染色体数目检测及苗期抗病性鉴定。结果表明中间偃麦草的倍性单一,153个品系中只检测到六倍体类型,而其余4个种的染色体倍性变化范围很广。尤其在二倍体长穗偃麦草中,倍性的变异最为丰富,出现了包括六倍体、八倍体、九倍体、十倍体和混合倍性在内的5种类型。此外,一部分多倍体材料的染色体数目固定不变,说明这些品系由稳定的整倍体单株组成。然而,有相当一部分的多倍体品系既含有整倍体单株又含有非整倍体单株,从而形成了染色体数目在一定范围内变动的混合群体。通过比较染色体组倍性与苗期抗秆锈病性的关系,我们发现倍性水平越高,其苗期抗秆锈病能力越强。例如,十倍体品系对秆锈病菌表现为免疫或高抗,而多数二倍体、四倍体、六倍体品系对秆锈病菌表现为中抗。我们推测十倍体品系可能携带多个抗秆锈病基因,不同抗病基因的加性效应或同一抗病基因的剂量效应使得十倍体品系对秆锈病表现出高抗特性。

关键词：偃麦草属倍性水平小麦秆锈病

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人工晶体学报 2005年第6期34卷 1126-1131页

作者：秦臻韩平韩甜甜鄢波李志兵谢自力朱顺明符凯刘成祥王荣华李云菲 s.xu N.Jiang 顾书林张荣郑有炓南京大学物理系江苏省光电信息功能材料重点实验室 Plasma sources and Applications Centre NIENanyang Technological UniversitySingapore 637616

本工作用化学气相淀积方法在A lN/s i(100)复合衬底上生长s iC薄膜。外延生长过程中,采用C4H4和s iH4作为反应气源,H2作为载气。样品的X-射线衍射谱和拉曼散射谱显示,所得到的外延层为六角对称的s iC薄膜。俄歇电子能谱及X-射线光电子... 详细信息

本工作用化学气相淀积方法在A lN/s i(100)复合衬底上生长s iC薄膜。外延生长过程中,采用C4H4和s iH4作为反应气源,H2作为载气。样品的X-射线衍射谱和拉曼散射谱显示,所得到的外延层为六角对称的s iC薄膜。俄歇电子能谱及X-射线光电子能谱的测量结果表明,在外延膜中存在来自衬底的A l和N元素。样品的光致发光测量显示,所有的样品均可在室温下观察到位于3.03 eV和3.17 eV处的发光峰,这分别相应于4H-s iC能带中电子从导带到A l受主能级之间的辐射跃迁和电子从N施主能级到价带之间的辐射跃迁,从而表明所得的外延薄膜的多形体为4H-s iC。

关键词： CVD 4H—siC 光致发光

前列腺癌:多参数MR成像与数字组织病理学的相关性研究

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国际医学放射学杂志 2017年第6期 723-724页

作者： J.T.Kwak s.sankineni s.xu B.Turkbey P.L.Choyke P.A.Pinto 仲津漫 Center for Interventional Oncology National Institutes of Health

摘要目的探究前列腺多参数MR成像和定量数字组织病理学分析(DHA)的相关性。材料与方法本回顾性研究符合HIPAA,并获得当地机构伦理委员会批准。纳入40例病

关键词： MR DHA 多参数组织病理学