材料期刊网

Characterization of Failure Mechanisms of Duplex and Graded Thermal Barrier Coatings Exposed to Thermal Shock Test

A.F.Waheed and H.M.Soliman(Dept. of Metallurgy , Nuclear Research Center , Atomic Energy Authority , Cairo , Egypt)

材料科学技术（英文）

The beginning of failure of a (ZrO2-7%Y2O3)/(Ni-22%Co-17%Cr-12.5%Al-0.6%Y) duplex andgraded coating systems on lnconel 617 and IN738LC in burner rig tests has been characterized.The test conditions are 40 s heating up to 75O℃ substrate temperature followed by 80 s aircooling. Failure is considered at the appearance of the first bright spot during heating period.Stresses due to thermal expansion mismatch strains on cooling are the probable cause of life-limiting in this conditions of testing.

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Studies on the EPR parameters for the rhombic Co2+ center in magnesium acetate

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The electron paramagnetic resonance (EPR) g factors g(i) (i = x,y,z) and the hyperfine structure constants A(i) for the rhombic Co2+ center in magnesium acetate are theoretically studied from the perturbation formulas of these parameters for a 3d(7) ion under rhombic symmetry. In these formulas, the contributions from the admixture among different states, covalency effect and rhombic crystal-fields are taken into account. The related crystal-field parameters are determined from the superposition model and the local geometrical relationship of the impurity center. The calculated results show reasonable agreement with the observed values. In addition, the nuclear quadrupole interaction constant is analyzed, and its negative sign is verified theoretically.

关键词: electron paramagnetic resonance (EPR);crystal- and ligand-fields;Co2+;magnesium acetate;atomic screening constants;paramagnetic-resonance;superposition model;aqueous-solutions;scf functions;g-tensor;crystal;fields;sites;liyf4

Implementation of quantum logic gates by nuclear magnetic resonance spectroscopy

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

Theoretical studies of the EPR parameters and the local structure of the tetragonal Fe+ center in KTaO3

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The EPR parameters (zero-field splitting D and g factors g(parallel to) and g(perpendicular to)) and the local structure for the tetragonal Fe+ center in KTaO3 are theoretically studied by using the perturbation formulas of the EPR parameters for a 3d(7) ion in tetragonally distorted dodecahedra. Based on these studies, we find that the impurity Fe+ may not locate on the regular dodecahedral K+ site but suffer a large off-center displacement Delta Z (approximate to 0.43 angstrom) along one of the < 100 > (or C-4) axes, which is responsible for the large tetragonal distortion of the impurity center. The displacement Delta Z obtained in this work is comparable with that (approximate to 0.46 angstrom) of a similar monovalent Li+ on K+ site of KTaO3 obtained from the nuclear quadrupole shift and can be regarded as reasonable. The calculated g factors, particularly the anisotropy Delta g (= g(perpendicular to) - g(parallel to)) based on the above displacement, agree with the observed values.

关键词: defect structures;electron paramagnetic resonance (EPR);crystal- and;ligand-fields;Fe+;KTaO3;electron-paramagnetic-resonance;atomic screening constants;nominally;pure ktao3;scf functions;dipole glass;ions;impurities;scattering;crystal;sites

Geometric matrix research for nuclear waste drum tomographic gamma scanning transmission image reconstruction

ZHANG Jin-Zhao , TUO Xian-Guo

中国物理C doi:10.1088/1674-1137/39/6/068202

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Review On Research And Development Of Magnesium Alloys

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 , null , null

Modeling flow stress constitutive behavior of SA508-3 steel for nuclear reactor pressure vessels

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

Opening Ceremony of Sichuan Rare-Earth Research Center & Ruisi Rare-Earth Company Holding in Sichuan University

稀土学报(英文版)

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Opening Ceremony of Sichuan Rare-Earth Research Center & Ruisi Rare-Earth Company Holding in Sichuan University

稀土学报(英文版)

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Opening Ceremony of Sichuan Rare-Earth Research Center & Ruisi Rare-Earth Company Holding in Sichuan University

稀土学报(英文版)

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