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SURFACE STATE AND CATALYTIC ACTIVITY OF ACTIVATED AMORPHOUS Fe_(80)Zr_(12)B_8 ALLOY

WANG Xike SHEN Ningfu CHEN Haisong Zhengzhou Institute of Technology , Zhengzhou , ChinaZHANG Haifeng Luoyang Research Institute for Ship Materials , Luoyang , ChinaGU Haicheng Xi'an Jiaotong University , Xi'an , China Professor , Research Centre for Materials , Zhengzhou Institute of Technology , Zhengzhou 450002 , China

金属学报(英文版)

The depth profile of composition,chemical state of elements and morphology of as- received and activated amorphous Fe_(80)Zr_(12)B_8 alloy ribbons have been studied by means of Auger electron spectroscopy,X-ray photoelectron spectroscopy and scanning Auger microprobe combined with Ar ion bombardment.Both dull and free sides of the as- received ribbons were covered with an iron oxide layer.While a pronounced surface segregation and oxidation of B and precipitation of microcrystalline α-Fe particles were observed on both sides of activated ribbons,B and Zr were oxidized selectively in subsurface layer.On both sides of ribbons,a porous surface structure formed. The BET surface area was measured to be increasing from 0.11 to 2.68 m~2/g.The principal mechanism of in situ activation has been discussed.

关键词: amorphous Fe_(80)Zr_(12)B8 alloy , null , null , null

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

Chen系统的状态变量周期性反馈控制

李开明 , 李亚洲 , 冯维贵 , 林长

量子电子学报 doi:10.3969/j.issn.1007-5461.2007.05.014

采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.

关键词: 混沌 , Chen系统 , 不动点 , Lyapunov指数 , 反馈控制

Titanium technology in the USA - an overview

D.Eylon , S.R.Seagle

材料科学技术(英文)

The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of "information-age" tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.

关键词:

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

Journal of Materials Research

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

关键词: room-temperature

Development and application of universal formability technology

Yanwu Xu

材料科学技术(英文)

Using mathematical plasticity theories, universal formability (UF) technology has been developed and applied in the automotive stamping engineering and production. As a formability analysis tool, this technology is the major methodology for the development of stamping expert system (solution provider) for (a) product design and feasibility analysis, (b) material automatic selection using nomograms, (c) draw die design using pre-models, and (d) UF and robustness analysis of die performance in finite element analysis (FEA) environment.

关键词:

Residual Stresses in Coating Technology

G.Montay , A.Cherouat , A.Nussair , J.Lu

材料科学技术(英文)

Residual stress in coatings is the result of individual particle stress. Their effects may be either beneficial or detrimental, depending upon the magnitude, sign and distribution of the stresses with respect to the external load. Tensile stress which exceeds the elastic limit causes cracking in surface coatings or at the interface between the substrate and the coat. Compressive stress, in general, has a beneficial effect on the fatigue life, crack propagation, coating adhesion and on the durability of the top coat during service. Compressive residual stresses can increase the number of cycles before crack initiation begins through a mean stress effect. Temperature gradients which occur during solidification and subsequent cooling are the principal mode of internal stresses generation. Some parameters influence the residual stress field of both the coating and the substrate. Substrate nature, spraying temperature, thickness of the coat layer, substrate preparation (grit blasting conditions), and velocity of the splats are in the relation with the quality of the coating. In this work, we will describe the role playing by the ceramics coating elaboration on the residual stress gradient in depth of the component. The incremental hole drilling technique has been developed to determine the residual stress gradient in depth of the coat and substrate which must be used with particularly conditions. This new technology has been employed on zirconia, alumina and tungsten carbide plasma sprayed coating.

关键词: Coating , null , null , null

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