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Microstructure and performance of AZ80D magnesium alloy by purification of chloride flux containing Er

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Rare Metals 2014年第5期33卷 541-546页

作者： Zhong-Jun Wang Guan-Qiao Su Wei-Ping Jia qing-xiang yang School of Material and Metallurgy University of Science and Technology Liaoning Key Laboratory of Materials Forming and Microstructure and Properties Control Education Department in Liaoning Province State Key Laboratory of Metastable Materials Science and Technology College of Materials Science and EngineeringYanshan University

The purification effects of Er addition in chloride flux during smelting on microstructure, tensile properties, and corrosion resistance of as-cast AZ80 D magnesium alloy were carried out. The results show that Er addition in the flux can eliminate the MgO inclusions and improve the tensile properties and corrosion resistance of the alloy. Using chloride flux mixed with 8.0 wt% Er, σb and δ of the as-cast AZ80 D magnesium alloy can be improved from 150 MPa and 2.1 % to the maximum value of 230 MPa and 4.8 %, respectively. Meanwhile, the corrosion rate decreases from 1.10 to 0.12 mg·（cm^2·d）^-1 in 5 wt% NaCl solution. However, with increasing Er content in chloride flux further, φ-（Al7ErMn5） and τ-（Al66.7Mg23.3Er10） phase are formed, and the morphology of γ-（Mg17Al12） phase is modified. The coarse φ-（Al7ErMn5）phase along dendrite boundaries decreases cohesion force between dendrites, which results in the worse of tensile properties.

关键词： Er Chloride flux AZ80D Microstructure Magnesium alloy

3D stress simulation and parameter design during twin-roll casting of 304 stainless steel based on the Anand model

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 666-673页

作者： Jing Guo Yuan-yuan Liu Li-gang Liu Yue Zhang qing-xiang yang State Key Laboratory of Metastable Materials Science & Technology Yanshan University Nanjing Iron & Steel Co. School of Material Science and Engineering University of Science and Technology Beijing

This study first investigated cracks on the surface of an actual steel strip. Formulating the Anand model in ANSYS software, we then simulated the stress field in the molten pool of type 304 stainless steel during the twin-roll casting process. Parameters affecting the stress distribution in the molten pool were analyzed in detail and optimized. After twin-roll casting, a large number of transgranular and intergranular cracks resided on the surface of the thin steel strip, and followed a tortuous path. In the molten pool, stress was enhanced at the exit and at the roller contact positions. The stress at the exit decreased with increasing casting speed and pouring temperature. To ensure high quality of the fabricated strips, the casting speed and pouring temperature should be controlled above 0.7 m/s and 1520℃, respectively.

关键词： stainless steel strip metal roll casting stress surface cracks numerical analysis

Hot deformation behavior of a Cr-containing low carbon steel in the ferrite range

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International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 549-553页

作者： Hai-feng Dong Da-yong Cai qing-xiang yang Yue Zhang Bo Liao State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

A low carbon steel with Cr addition of 0.46wt% combined with trace elements of Mn and Ti was studied. The apparent activation energy of deformation and the hot deformation equation of the steel in the ferritic range were determined by means of single hot compression tests. The hot-rolled strip of 3 mm in thickness rolled in the ferritic range was obtained using a laboratory hot rolling mill. The mechanical properties show that the values of yield strength and ultimate tensile strength are 230 and 330 MPa, respectively, and the elongation is 33%. The average r-value is 1.1. Large polygonal ferrite recrystallization grains with about 40 grn in size and the strong { 111 } recrystallization texture can be obtained in the hot-rolled strip.

关键词： low carbon steel hot deformation ferritie rolling mechanical properties texture

Solid Solute Regularity of La Atom inα-Fe Supercell by First-principles

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Journal of Iron and Steel Research International 2016年第11期23卷 1213-1218页

作者： Cai-xia WANG Jian yang Sha LIU Xiao-lei XING Ji-bo WANG Xue-jun REN qing-xiang yang State Key Laboratory of Metastable Materials Science and Technology Yanshan University School of Materials Science and Engineering University of Science and Technology Beijing School of Engineering Liverpool John Moores University

The structure stability, elastic property and electronic structure of a-Fe supercell with La atom were inves- tigated by first-principles, in which, generalized gradient approximation （GGA） with the Perdew Burke Ernzerhof （PBE） was used as exchange-correlation functional, a-Fe supercells with La atom include a-Fe supercell with La atom in octahedral interstitial solid solute （La-OISS）, that with La atom in tetrahedral interstitial solid solute （La-TISS） and that with La atom in substitutional solid solute （La-SSS）. The results show that the La-SSS a-Fe supercell is more stable than La-OISS one. The resistance to volume change, reversible deformation and stiffness of La-OISS a-Fe supercell are stronger than those of La-SSS one. Moreover, the degrees of anisotropy and ionization in La-SSS a-Fe supercell are both stronger than those in La-OISS one. The bonding strength between La atom and Fe atom in La-SSS a-Fe supercell is larger than that in La-OISS one.

关键词： La atom a-Fe supercell solid solution first-principles bonding strength

Study on stable and meta-stable carbides in a high speed steel for rollers during tempering processes

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International Journal of Minerals,Metallurgy and Materials 2013年第2期20卷 146-151页

作者： Jing Guo Hong-wei Qu Li-gang Liu Yan-liang Sun Yue Zhang qing-xiang yang State Key Laboratory of Meta-stable Materials Science and Technology Yanshan University School of Material Science and Engineering University of Science and Technology Beijing

A high speed steel （HSS） was studied for rollers in this work. The steel was quenched at 1150℃ and tempered at 520℃. The phase structures of the steel were determined by X-ray diffraction （XRD）, and the hardness of specimens was measured. The volume fraction of carbides was counted by Image-Pro Plus software. The typical microstructures were observed by field emission scanning electron microscope （FESEM）. Stable and meta-stable carbides were deduced by removing the existing phases one by one in the Fe-C equilibrium calculation. It is found that the precipitated carbides are bulk-like MC, long stripe-like M2C, fishbone-like M6C, and daisy-like M7C3 during the tempering process. The stable carbides are MC and M6C, but the meta-stable ones are M2C, M7C3, and M3C.

关键词： high speed steel phase diagrams tempering carbides

Numerical simulation of the temperature fields of stainless steel with different roller parameters during twin-roll strip casting

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 304-308页

作者： Yuan Fang Zhen-min Wang qing-xiang yang Yun-kun Zhang Li-gang Liu Hong-yan Hu Yue Zhang School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Key Laboratory of Metastable Materials Science ＆ Technology College of Materials Science and Engineering Yanshan University Qinhuangdao 066004 China

The temperature field of stainless steel during twin-roll strip casting was simulated by experiment and a finite element （FE） model. By comparing the measured result with the simulated values, it is found that they fit close to each other, which indicates this FE model is effective. Based on this model, the effects of roll gap （t） and roll radius （R） on solidification were simulated. The simulated results give the relationship between t or R and the position of the freezing point. The larger the t is and the smaller the R is, the closer the position of the freezing point is to the exit.

关键词： twin-roll strip casting temperature field roll gap roll radius numerical simulation

川西北民族地区保护区建设与生态移民问题研究

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长江流域资源与环境 2006年第6期15卷 691-697页

作者：卿向阳西南科技大学四川绵阳621000

四川省西北部地区是以藏羌民族集居为主的民族地区,也是四川省的生态资源中心。区域内自然保护区数量多、密度大,民族文化浓郁,经济发展落后,居民城市化率低。由于早期建立保护区指导思想的制约,现已建立的多数保护区的规划缺乏系统科学... 详细信息

四川省西北部地区是以藏羌民族集居为主的民族地区,也是四川省的生态资源中心。区域内自然保护区数量多、密度大,民族文化浓郁,经济发展落后,居民城市化率低。由于早期建立保护区指导思想的制约,现已建立的多数保护区的规划缺乏系统科学性,依然存在来自区域内部居民和外部经济活动对其的破坏。研究认为,要实现为区域社会经济可持续发展创造条件的保护区设立终极目的,必须对现有的保护区管理系统实施调整与完善,建立具有政府管理职能的资源保护特区,选择以城镇化为主要方式的保护区内就近生态移民,构建科学的自然保护区层次,形成政府(资源保护特区)与民族居民的资源保护利益共同体。

关键词：民族地区生态移民城镇化生态资源特区

企业组织虚拟化——中国民营企业规模化发展的有效途径

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商业研究 2006年第9期 72-77页

作者：卿向阳西南科技大学管理学院四川锦阳621000

民营企业是我国改革开放的产物。经过20多年的变革,民营企业在我国社会经济发展中的地位与作用已为国内外所公认。我国民营企业发展多数都具有组织、聚合能力差的先天缺陷,导致后天经营规模小、持续发展弱。在我国全面实现小康社会阶段... 详细信息

民营企业是我国改革开放的产物。经过20多年的变革,民营企业在我国社会经济发展中的地位与作用已为国内外所公认。我国民营企业发展多数都具有组织、聚合能力差的先天缺陷,导致后天经营规模小、持续发展弱。在我国全面实现小康社会阶段,众多的中小民营企业面临着再发展的机遇与资源聚合能力差而再发展艰难的挑战。选择以企业组织方式为突破口,走企业组织虚拟化的道路以充分地发挥企业的核心能力,采用虚拟生产组织、建立虚拟共生作业中心、形成虚拟显性能力矩阵是民营企业克服先天不足,提高资本效率以产生资源博弈效益,实现民营企业的再次发展的有效途径之一。

关键词：企业组织虚拟化民营企业规模化途径

A Study on Bilirubin Radical Cation Generated by One-Electron Oxidation

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Chemical Research in Chinese Universities 1992年第3期8卷 301-304页

作者： GUO qing-xiang, yang Li, LIU Bo and LIU You-cheng(National Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, 730000)

Introduction Bilirubin (BR) is generally regarded as a toxic compound when accumulated at an abnormally high concentration in biological tissues, and in fact a normal adult man produces about 300 mg of BR a day. However, it was proposed that the bile pigments BR and biliverdin(BV), which is the precursor of BR, may protect vitamin A and linoleie acid from oxidative destruction in the intestinal tract Further stud

关键词： Bilirubin Electron transfer Radical cation