材料期刊网

STUDY OF THE MICROSTRUCTURE AND PROPERTIES OF SIMULATED HEAT AFFECTED ZONE IN LASER WELDING OF ULCB 600 STEEL

Q. F. Wang , J. H. Liu , Z. Y. Li , P. H. Li , G. F. Zhou and X. Chen( 1) Huazhong University of Sci. & Tech. , Wuhan 430074 , China 2) Technology Center of WISCO , Wuhan 430080 , China)

金属学报(英文版)

The microstructure and properties of stmulated heat affected zone (HAZ) of laser welded ULCB600 steel were investigate by applying the simulation technique with gleeble - 2000 dynamic thermal - me - chanical simulator.The influence of the preheat condition on the microstructure and properties of simu- lated HAZ of laser welded plate was also studied in order to evaluate the feasibility of reducing arisk that the ductility and toedness of HAZ may be poor by using preheat treatment.The results indicate that the grain size of laser - welded HAZ simulated is very small no matter if there is preheat, the toughness of simulated HAZ is therefore improved comparing to the base metal,and there is no obvious brittle - ductile transition in the range from - 80℃ to 20℃. The TEM analyses of sub -microstruc- ture also discover that microstructure constituent of both simulated HAZ is dominative lath martensite. However, the shaf of martensite is relatively coarse,and the dislocation density is relatively high for simulated HAZ with 200℃ preheat because of slower cooling rate. Combination of these tow factors is responsible for farer bardness and better toughness of simulated HAZ with preheat condition.

关键词: physical simulation laser beam welding , null , null

Recent Advances of Laser Coating Technology in China

LIANG Yong LI Ruiguo Institute of Metal Research , Academia Sinica , Shenyang 110015 , ChinaInstitute of Corrosion and Protection of Metals , Aademia Sinica , Shenyang , 110015 , China

材料科学技术（英文）

Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.

关键词: laser , null , null , null , null

Defect model for a tetragonal Co2+ impurity center in AgCl crystal

Materials Science and Engineering B-Solid State Materials for Advanced Technology

The EPR g-factors g(parallel to), g(perpendicular to) and hyperfine structure constants A(parallel to), A(perpendicular to) for a tetragonal Co2+ impurity center (i.e. Co2+ (II) center) in AgCl crystal are calculated by using the perturbation formulas of EPR parameters for the 3d(7) ion in tetragonal symmetry obtained from the cluster approach. Based on the calculations, the defect model for the center is suggested as a substitutional Co2+ ion associated with a nearest neighbour O2- ion. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词: defect model;electron paramagnetic resonance;crystal-field theory;ligand-field theory;Co2+;AgCl;transition

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 paramaters and defect structure of the trigonal Ti2+ center in ZnS

Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy

The axial Ti2+ center in a nearly wholly cubic ZnS crystal is assigned to the Ti2+ ion on the hexagonal site of wurtzite structure caused by stacking faults. On the ground of the assignment, the EPR parameters (zero-field splitting D, g factor g(parallel to) and g-anisotropy Delta g = g(parallel to) - g(perpendicular to)) of the axial Ti2+ center are calculated from the high-order perturbation formulas based on the cluster approach for the EPR parameters of 3d(2) ion in trigonal symmetry. From the calculations, the local atom-position parameter u(loc) (which is different from the corresponding parameter u in the host wurtzite structure) and hence the defect structure of the Ti" center are estimated. The results (the calculated EPR parameters and the defect structure) are discussed. (c) 2004 Elsevier B.V. All rights reserved.

关键词: electron paramagnetic resonance (EPR);local lattice distortion;crystal- and ligand-field;Ti2+;ZnS;electron-spin resonance;superposition model;zinc-sulfide;crystals;absorption;ions;fe3+;site

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

EPR investigation of the structure of a rhombic Co2+ center in an NaF crystal

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The local structure of the rhombic Co2+ center in NaF crystal is investigated by using the perturbation formulas of electron paramagnetic resonance (EPR) g factors g(i) (i - x,y,z) and hyperfine constants A(i) for a 3d(7) (Co2+) ion in rhombic octahedral symmetry based on a cluster approach. In these formulas, the contributions from the admixture among different states, covalency effect as well as rhombic crystal field are included. By studying the EPR data of the rhombic Co2+ center, one can reasonably obtain the local structural (or rhombic distortion) parameters DeltaR(c)(approximate to 0.268 Angstrom) for the central Co2+ and DeltaR(p)(approximate to 0. 181 Angstrom) for the two F- ions along [100] and [010] axes closest to the Na+ vacancy V-Na. The reasonableness of the results is also discussed.

关键词: local geometry;electron paramagnetic resonance (EPR);crystal- and;ligand field theory;NaF;Co2+;atomic screening constants;superposition model;scf functions;parameters;electrons;resonance;ions;cr3+

Defect structure of Co2+ center in rhombohedral BaTiO3

Optical Materials

The spin-Hamiltonian parameters (g factor g(parallel to), gi(perpendicular to) and hyperfine structure constants A(parallel to), A(perpendicular to)) of Co2+ ion in rhombohedral BaTiO3 crystal are calculated from the perturbation formulas based on the cluster approach for the spin-Hamiltonian parameters of 3d(7) ion in trigonal octahedral site. The calculations are related to the trigonal field parameters and hence to the defect structure of Co2+ center. From the calculations, it is found that in order to reach a good fit between calculations and experiments, the off-center displacement of Co2+ ion in oxygen octahedron of BaTiO3 is much smaller than that of the host Ti4+ ion it replaces. This point is similar to the case of Fe3+ ion in BaTiO3 obtained in the previous studies by analyzing EPR zero-field splitting from the superposition model. (c) 2005 Elsevier B.V. All rights reserved.

关键词: defect structure;electron paramagnetic resonance;crystal and ligand;field;photorefractive material;Co2+;BaTiO3;electron-paramagnetic-resonance;atomic screening constants;photorefractive properties;superposition model;scf functions;dependence;position;distance;fields;sites

Treatment of Reused Comprehensive Wastewater in Iron and Steel Industry With Electrosorption Technology

ZHANG Yunhua , GAN Fuxing , LI Meng , WANG Dihua , HUANG Zhongmai , GAO Yunpeng

钢铁研究学报(英文版)

Electrosorption technology was used to treat the reused comprehensive wastewater from iron and steel industry. A problem of relatively high conductivity of wastewater which greatly affects the reuse was examined, and industrial test was conducted for the reused water advanced deionization and purification in a comprehensive wastewater treatment plant of WISCO [Wuhan Iron and Steel (Group) Corporation]. The results of the onsite industrial test showed a satisfactory treatment performance for the reused water even at a flow rate of 1000 L/h in a standard 500 L/h unit. The average conductivity decreased by about 70%, from 580-780 μS/cm to 100-350 μS/cm. The average removal efficiency of Cl- and Ca2+ was about 75% and 68%, respectively, and CODCr of the treated water was also reduced in some degree while the pH value was almost unchanged. The energy consumption was as low as 06 kWh/t, which was remarkably superior to the conventional technologies. Therefore, it is entirely feasible that the novel electrosorption technology can be used in enhanced desalination and purification treatment of reused comprehensive wastewater in iron and steel industry.

关键词: electrosorption , desalination , purification , conductivity , industrial reused water

Defect structure of the tetragonal Cu2+ center in PbTiO3 : Cu2+ crystal

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

defect structure of the tetragonal Cu2+ center in PbTiO3: Cu2+ crystal is studied by analyzing the EPR g factors and hyperfine structure constants. From the study, we suggest that an oxygen vacancy occurs in the nearest-neighbors site of Cu2+ due to charge compensation, and that the off center displacement of Cu2+ is smaller than that of the replaced host ion Ti4+. The reasonableness of the defect structure is discussed.

关键词: defect structure;electron paramagnetic resonance;crystal-field theory;Cu2+;PbTiO3;electron-paramagnetic-resonance;superposition model;single-crystals;batio3;ions;ni