材料期刊网

NUMERICAL SIMULATION OF ROUND TO OVAL ROLLING PROCESS

Y. W. Wang , Y. L. King , D. H. Yuan , S. G. Liu and Z. Y. Yu 1 ) University of Science and Technology Beijing , Beijing 100083 , China 2) Daye Special Steel Co. , Huangshi 435001 , China

金属学报(英文版)

Three dimensional thermal-mechanical coupled elasto-plastic FEM has been used for simulation of round to oval single pass rolling. The analysis was conducted using MARC/AUTOFORCE1. 2 code. The material is assumed to be elasto-plastic and it obey the Von Mises yield criterion and Prandtl- Reuss rule. Deformation of the workpiece is simulated in a step-by-step manner,updating the coordinates of material points and the property after each step, so that both nonsteady-state and stendy-state deformation can be simulated. The heat transfter between the workpiece, the rolls, and enviroment and the heat generation due to plastic work and friction force, are considered in the analys- is.Predicted the deformation shape of the workpiece, distributions of strains, stresses, strain rates and temperatures, roll-separating force and roll torque are presented.

关键词: bar rolling , null , null , null

Fe2+对嗜铁钩端螺旋菌L. ferriphilum生长活性的影响

高健 , 康健 , 吴学玲 , 徐競 , 李邦梅 , 邱冠周

中国有色金属学报

以分离于江西某铜矿的嗜铁钩端螺旋菌(L. ferriphilum YSK)菌株为研究对象,报道不同Fe2+浓度对 L. ferriphilum生长活性的影响.结果表明,YSK菌株生长最适宜的Fe2+浓度约为0.1 mol/L.当初始Fe2+浓度为0.4 mol/L时,进入对数生长期前很明显需要一个较长的延迟期,表明该Fe2+浓度对细胞的生长产生较强的抑制作用;当初始Fe2+浓度为0.6 mol/L时,YSK菌株的生长完全受到抑制.尽管高浓度的Fe2+抑制细胞的生长,但受到抑制而不生长繁殖的YSK细胞仍然具有氧化Fe2+的能力.

关键词: L.ferriphilum YSK菌株 , Fe2+ , 生长活性

Distribution, Transportation and Cytolocalization of Neodymium in Oilseed Rape (Brassica napus L.)

魏幼璋

稀土学报(英文版)

关键词:

Distribution, Transportation and Cytolocalization of Neodymium in Oilseed Rape (Brassica napus L.)

魏幼璋

稀土学报(英文版)

关键词:

Distribution, Transportation and Cytolocalization of Neodymium in Oilseed Rape (Brassica napus L.)

魏幼璋

稀土学报(英文版)

关键词:

Distribution, Transportation and Cytolocalization of Neodymium in Oilseed Rape (Brassica napus L.)

魏幼璋

稀土学报(英文版)

关键词:

Distribution, Transportation and Cytolocalization of Neodymium in Oilseed Rape (Brassica napus L.)

魏幼璋

稀土学报(英文版)

关键词:

Distribution, Transportation and Cytolocalization of Neodymium in Oilseed Rape (Brassica napus L.)

魏幼璋

稀土学报(英文版)

关键词:

Sm对Mg-l0Y合金组织的细化作用

张清 , 李全安 , 井晓天 , 张兴渊

材料工程 doi:10.3969/j.issn.1001-4381.2011.03.016

Mg24Y5相的细化是进一步提高Mg-l0Y合金力学性能的关键.研究了稀土元素sm对Mg-l0Y合金中的Mg24Y5相及其基体组织的细化作用,结果表明:sm的加人,改善了Mg24Y5相的形貌,促进了细小弥散分布的Mg24Y5颗粒相的形成;同时,Sm的加人,通过固溶作用,进一步细化了基体组织;显微组织的改善导致了合金高温下力学性能的提高.

关键词: Sm , Mg-10Y合金 , 组织细化 , 力学性能

L1(2)- and L1(0)-like cation-ordered structures in ZrO2-Y2O3 ceramics

Journal of Materials Research

Y0.25Zr0.75O2-x and Y0.5Zr0.5O2-y phases, with L1(2-) and L1(0-) like cation-ordered structures, respectively, have been found in ZrO2-Y2O3 ceramics in both the sintered and annealed states. High-resolution electron microscopy, energy-dispersive x-ray spectroscopy and computer simulation have been used to reveal the presence of the phases. The formation of Y0.25Zr0.75O2-x, and Y0.5Zr0.5O2-y phases was initiated during the sintering procedure and developed with the increase in annealing temperature and time. Segregation of yttrium, which was prevalent in different regions even within one grain, induced the formation of Y0.25Zr0.75O2-x and Y0.5Zr0.5O2-y phases.

关键词: yttria-stabilized zirconia;percent y2o3 alloy;x-ray-diffraction;solid-solutions;electron-diffraction;neutron-diffraction;modulated;structure;diffuse-scattering;average structure;tetragonal phase