Liping ZHENG Xiqing XIA Mingyao LI Shanghai Institute of Nuclear Research
,
Academia Sinca
,
Shanghai
,
201800
,
ChinaRisheng LI Lab.of Atomic Imaging of Solids
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
Correlations between surface composition changes and ion bombardment fluences were studied for multicomponent materials by using a dynamic Monte Carlo program,including the preferential sputtering and bombardment-induced Gibbsian segregation (BIGS) processes.For the case of 1 keV KR-~(10)B_(0.02)~(11)B_(0.08) (the most simple multicomponent material system),it is found that the ~(10)B composition enriches at the surface at low fluences but depletes at the surface at high fluences.For the case of 1 keV Ar-Pt_(0.5)Cu_(0.5).it is found that the Cu composition at the topmost surface is always under the bulk composition between zero and high fluences,but the evident composition gradient of Cu(the segregation species) exists in the surface at low fluences.The effects of the preferential sputtering and BIGS processes on above two surface composition profiles are also discussed.
关键词:
implantation
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null
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null
Chinese Physics Letters
Using nuclear magnetic resonance techniques with a solution of cytosine molecules, we show an implementation of certain quantum logic gates (including NOT gate, square-root of NOT gate and controlled-NOT gate), which have central importance in quantum computing. In addition, experimental results show that nuclear magnetic resonance spectroscopy can efficiently measure the result of quantum computing without attendant wave-functions collapse.
关键词:
computation;universal;computer
MA Zongyi YAO Zhongkai Harbin Institute of Technology
,
Harbin
,
China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
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null
,
null
,
null
Z. Yang
,
J.P. Li
,
J.X. Zhang
,
G.W.Lorimer
,
J. Robson
,
null
,
null
,
null
,
null
金属学报(英文版)
The current research and development of magnesium alloys is summarized. Several aspects of magnesium alloys are described: cast Mg alloy, wrought Mg alloy, and novel processing. The subjects are discussed individually and recommendations for further study are listed in the final section.
关键词:
Magnesium alloys
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null
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null
Journal of Nuclear Materials
Based on the measured stress-strain curves under different temperatures and strain rates, a series of flow stress constitutive equations for SA508-3 steel were firstly established through the classical theories on work hardening and softening. The comparison between the experimental and modeling results has confirmed that the established constitutive equations can correctly describe the mechanical responses and microstructural evolutions of the steel under various hot deformation conditions. We further represented a successful industrial application of this model to simulate a forging process for a large conical shell used in a nuclear steam generator, which evidences its practical and promising perspective of our model with an aim of widely promoting the hot plasticity processing for heavy nuclear components of fission reactors. (c) 2011 Elsevier B.V. All rights reserved.
关键词:
low-alloy steels;low-carbon steel;hot deformation;mechanical-properties;fracture-toughness;temperature;austenite;working
