YU Fanghua YANG Guohua Shanghai Institute of Nuclear Research
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Academia Sinica
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Shanghai
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ChinaHAN Rongdian WENG Huimin University of Science and Technology of China
,
Hefei
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ChinaSHEN Jianian Corrosion Science Laboratory
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Institute of Corrosion and Protection of Metals Academia Sinica
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Shenvang
,
China
金属学报(英文版)
The effects of small amount(≥0.05%)of active elements Y and Ce in Fe-25Cr-40Ni al- loy have been investigated on the kinetics of early stage of high temperature oxidation as well as composition and microsructure of oxide film by ion backscattering and slow positron beam.The results show that Y and Ce can reduce evidently the high tem- perature oxidation rate of FeCrNi alloy at early stage and can effectively enhance the Cr_2O_3 formation and retard the oxide formation of Fe and Ni in the surface layer thus the microstructure of the oxide film is improved.Y and Ce enter the oxide film and concentrate within several tens nanometres from surface of the outer layer.The mech- anism of oxidation resistance for Ce is different from Y.Ce can decrease the density of vacancy defects in oxide layer,so the cations are restrained from diffusion outward through vacancies.While Y can control the outward diffusion of cations through va- cancies at the early statge of oxidation(shorter than 12 min),aften that restrained the cations from diffusion outward along grain boundaries up to 60 min oxidation.
关键词:
ion backscattering
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null
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null
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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
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null
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null
Z. Yang
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J.P. Li
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J.X. Zhang
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G.W.Lorimer
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J. Robson
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null
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null
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null
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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
