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THE ACCURATE MOLECULAR FORMULA OF "Ti_(11)Ni_(14)" PHASE

C.L. Chu , G.J. Shen , S.D. Wang , B. Li , S.G. Zhang and Z.D. Yin(BOX 433 , School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , China)(Analysis and Testing Center , Southeast University , Nanjing 210018 , China)(Research Institute of Electric Light Source Materials , Ministry of Light Industry , Nanjing 210015 , China)

金属学报(英文版)

From the orientation relationship between "Ti11Ni14" phase and matrix phase (B2),the accurate molecular formula of "Ti11N14" phase has been derived in this paper. The results also show that the rhombohedral unit cell of the "Ti11Ni14" phase includes six Ti atoms, seven Ni atoms and one vacancy, belonging to space group R3.

关键词: TiNi , null , null

Failure analysis of corrosion cracking and simulated testing for a fluid catalytic cracking unit

Journal of University of Science and Technology Beijing

The failure of a fluid catalysis and cracking unit (FCCU) in a Chinese refinery was investigated by using nondestructive detection methods, fracture surface examination, hardness measurement, chemical composition and corrosion products analysis. The results showed that the failure was caused by the dew point nitrate stress corrosion cracking. For a long operation period, the wall temperature of the regenerator in the FCCU was below the fume dew point. As a result, an acid fume NOx-SOx-H2O medium presented on the surface, resulting in stress corrosion cracking of the component with high residual stress. In order to confirm the relative conclusion, simulated testing was conducted in laboratory, and the results showed similar cracking characteristics. Finally, some suggestions have been made to prevent the stress corrosion cracking of an FCCU from re-occurring in the future.

关键词: stress corrosion cracking;fluid catalytic cracking unit;dew point;failure

Analysis of Ground-State Zero-Field Splitting for Mn(2+) in ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O)

Chinese Physics Letters

The electron paramagnetic resonance spectra of trigonal Mn(2+) centers in ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O) crystals are studied on the basis of the complete energy matrices for a d(5) configuration ion in a trigonal ligand field. It is demonstrated that the local lattice structure around a trigonal Mn(2+) center has an elongation distortion along the crystalline c(3) axis, and when Mn(2+) is doped in the ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O) crystals, there is a similar local distortion. From the EPR calculation, the local lattice structure parameters for trigonal Mn(2+) centers in ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O) are determined.

关键词: phase-transition;ions;complexes;crystals;spectra;fe-3+;epr

EPR parameters and superposition model analysis for trigonal Dy3+-O2- center in CaF2 crystal

Physica B-Condensed Matter

On the basis of the defect model of trigonal Dy3+-O2- center in CaF2, the EPR parameters (g factors and hyperfine structure constants) for this trigonal center are calculated from the perturbation formulas. In the formulas, the contributions to EPR parameters due to the J-mixing among H-6(J) (J = 15/2, 13/2 and 11/2) states, the mixtures among the states with the same J-value and those between the lowest Kramers doublet Gamma(gamma) and other Kramers doublets Gamma(X) are included. In the calculation, the crystal field parameters are estimated from the superposition model. From the calculation, the EPR g factors g(\\), g(perpendicular to) are reasonably explained and the superposition model intrinsic parameters (A) over bar (2)(F-) and (A) over bar (2) (O2-) with R = 2.366 Angstrom are obtained. (C) 2003 Elsevier B.V. All rights reserved.

关键词: EPR parameters;crystal-field theory;superposition model;Dy3+;CaF2;electron-paramagnetic-resonance;field parameters;single-crystals;ions

Comparative analysis of the difference of local structure between EPR theory and X-ray diffraction experiment for NiSiF(6)center dot 6H(2)O crystal

Journal of Alloys and Compounds

The local structure for NiSiF(6)center dot 6H(2)O crystal has been investigated by diagonalizing the complete energy matrices, By simulating the EPR and optical spectra, the local structure parameter theta(0) = 54.8901 is determined at room temperature and is different from theta(0)' = 55.0899 obtained by X-ray diffraction experiment, suggesting that: (i) the H(+) ions lead to a deviation of the equivalent position of effective charge of H(2)O molecule from O(2) ion, (ii) the neighboring [siF(6)](2) octahedral clusters lead to a deflection of the H(2)O molecules towards them. The deviation angle Delta theta(0) = -0.1999 is reported for file first time. Furthermore, the local structure NiSiF(6)center dot 6H(2)O crystal has been determined it 4.2 and 77 K. (c) 2007 Elsevier B.V. All rights reserved.

关键词: Local structure;Complete energy matrices;EPR theory;X-ray diffraction;experiment;NiSiF(6)center dot 6H(2)O crystal;electron-paramagnetic-resonance;nickel fluosilicate;magnetic-resonance;optical absorption;field;pressure;cobalt;fe-3+;zinc;ion

A CHALLENGE FOR BIAXIAL AND TRIAXIAL CREEP TESTING

M. Sakane (Department of Mechanical Engineering , Faculty of Science and Engineering , Ritsumeikan University , 1-1-1Nojihigashi Kusatsu-shi Shiga , 525-8577 , Japan)S. Mukai (Power Reactor and Nuclear Fuel Development Corporation , 4002 Narita-cho Oarai-cho Ibaragibun Ibaragi , 311-13 , Japan)

金属学报(英文版)

This paper describes new methods for biaxial and triaxial creep testing. Biaxial tension and triaxial tension creep testers were developed. The performance of the machines was described and some test results were discussed. Stress biaxiality had almost no effect on the creep deformation and Mises potential was suitable for describing the creep deformation under biaxial and triaxial stress states. Stress biaxiality had a small influence on prolonging creep rupture time under the constant Mises stress condition.A new triaxial tension creep testing method was discussed together with the shape of the triaxial creep specimen.

关键词: creep , null , null , null , null

Microsample tensile testing of nanocrystalline copper

Scripta Materialia

The tensile properties of nanocrystalline copper with grain sizes <100 nm produced by surface mechanical attrition treatment have been characterized using a microsample testing technique. The nanocrystalline copper exhibits a yield strength as high as 760 MPa, with a small elongation to failure. Factors leading to the high strength and low ductility are discussed. (C) 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

关键词: nanocrystalline materials;strength;ductility;fracture;copper;mechanical-behavior;metals;microstructure;ductility;strength;fatigue;alloy;cu

Development of rapidly quenched soft magnetic materials in China

Shaoxiong ZHOU

材料科学技术(英文)

The discovery of the first Fe-based ferromagnetic amorphous alloy in 1966 had made an impact on conventional magnetic materials because of its unique properties. Since then, a number of amorphous magnetic materials have been successfully developed and used in a wide variety of applications. A brief review of R & D activities on amorphous soft magnetic materials in China is given from the beginning to the present in a somewhat chronological order, followed by a brief introduction to their applications on electric and electronic industries. An analysis and a prospect of Chinese market of such amorphous materials are also presented.

关键词:

Evaluation of Young's Modulus and Residual Stress of NiFe Film by Microbridge Testing

Zhimin ZHOU , Yong ZHOU , Mingjun WANG , Chunsheng YANG , Ji'an CHEN , Wen DING , Xiaoyu GAO , Taihua ZHANG

材料科学技术(英文)

Microbridge testing was used to measure the Young's modulus and residual stress of metallic films. Samples of freestanding NiFe film microbridge were fabricated by microelectromechanical systems. Special ceramic shaft structure was designed to solve the problem of getting the load-deflection curve of NiFe film microbridge by the Nanoindenter XP system with normal Berkovich probe. Theoretical analysis of load-deflection curves of the microbridges was proposed to evaluate the Young's modulus and residual stress of the films simultaneously. The calculated results based on experimental measurements show that the average Young's modulus and residual stress for the electroplated NiFe films are 203.2 GPa and 333.0 MPa, respectively, while the Young's modulus measured by the Nano-hardness method is 209.6±11.8 GPa for the thick NiFe film with silicon substrate.

关键词: Mechanical properties , 金属薄膜 , 纳米压痕

Introduction to atmospheric corrosion research in China

Science and Technology of Advanced Materials

In this paper, we introduce the research on atmospheric corrosion in China. We describe the climate characteristics and the classification of atmospheric corrosivity across the whole country. We also describe the rusting evolution under simulated wet/dry cyclic conditions. (C) 2007 NIMS and Elsevier Ltd. All rights reserved.

关键词: atmospheric corrosion;corrosivity;rusting evolution;weathering steels;rust;mechanism;so2;o-3;no2

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