材料期刊网

Study on Grey Forecasting Model of Copper Extraction Rate with Bioleaching of Primary Sulfide Ore

A.X. Wu , Y. Xi , B.H. Yang , X.S. Chen , H.C. Jiang , null , null , null , null , null

金属学报(英文版)

A model GM (grey model) (1,1) for forecasting the rate of copper extraction during the bioleaching of primary sulphide ore was established on the basis of the mathematical theory and the modeling process of grey system theory. It was used for forecasting the rate of copper extraction from the primary sulfide ore during a laboratory microbial column leaching experiment. The precision of the forecasted results were examined and modified via "posterior variance examination". The results show that the forecasted values coincide with the experimental values. GM (1,1) model has high forecast accuracy; and it is suitable for simulation control and prediction analysis of the original data series of the processes that have grey characteristics, such as mining, metallurgical and mineral processing, etc. The leaching rate of such copper sulphide ore is low. The grey forecasting result indicates that the rate of copper extraction is approximately 20% even after leaching for six months.

关键词: primary copper sulfide ore , null , null

On the EPR parameters of divalent cobalt in ZnX (X = S, Se, Te) and CdTe

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The electron paramagnetic resonance (EPR) parameters g and the hyperfine structure constants A of CO2+ in ZnX (X = S, Se, Te) and CdTe are studied, using the perturbation formulas of the EPR parameters for a 3d(7) ion in tetrahedra based on two mechanism models. In these formulas, both the contributions from the conventional crystal-field (CF) mechanism and those from the charge-transfer (CT) mechanism are taken into account. According to the investigations, the sign of the g-shift DeltagCT from the CT mechanism is the same as DeltagCF from the CF mechanism, whereas the contributions to the A value from the CF and CT mechanisms have opposite signs. Particularly, the contributions to the EPR parameters from the CT mechanism increase rapidly with increase of the spin-orbit coupling coefficient of the ligand and the covalency effect of the systems, i.e. S2- < Se2- < Te2-.

关键词: crystal-fields and Spin Hamiltonians;EPR;Co2+;ZnX (X = S, Se, Te);CdTe;atomic screening constants;scf functions;field theory;cr2+ ion;spectra;znse;complexes;crystal;liyf4;znte

PbX(X=S,Se)纳米结构材料的制备方法

危兆玲 , 李天保 , 赵君芙 , 梁建 , 马淑芳 , 许并社

材料导报

PbX(X=S,Se)纳米结构材料因其良好的光电性能,在太阳能电池等方面有着较好的应用前景,目前已成为半导体领域的研究热点.概括和总结了几种制备PbX纳米材料的经典和新型方法,其中包括水热法、溶剂热法、化学气相沉积法、中孔材料模板法、熔盐籽晶法、纳米晶的取向附属物法和微波法等,并分析和讨论了各方法的特点及对应产物的特征.

关键词: PbS , PbSe , 制备方法 , 纳米结构

Chen系统的状态变量周期性反馈控制

李开明 , 李亚洲 , 冯维贵 , 林长

量子电子学报 doi:10.3969/j.issn.1007-5461.2007.05.014

采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.

关键词: 混沌 , Chen系统 , 不动点 , Lyapunov指数 , 反馈控制

Theoretical investigation of the spin Hamiltonian parameters and local structure and their concentration dependences for Cd(1-x)Mn(x)S quantum dots

Physica Scripta

The spin Hamiltonian parameters (zero-field splitting D, g factors and hyperfine structure constants) and local structure as well as their concentration dependences for Cd(1-x)Mn(x)S quantum dots are theoretically investigated from the perturbation formulae of these parameters for a 3d(5) ion under trigonally distorted tetrahedra. The impurity Mn(2+) is found not to occupy exactly the host Cd(2+) site in the CdS quantum dots but to experience an inward displacement 0.041 angstrom towards the ligand triangle along the C(3)-axis because of the size mismatching substitution and the internal stress. As compared with bulk CdS : Mn(2+), the larger impurity displacement and stronger Mn(2+) 3d-3s orbital admixture in the Cd(1-x)Mn(x)S quantum dots suitably account for the higher zero-field splitting and hyperfine structure constant, respectively. The impurity axial displacement and the Mn(2+) 3d-3s orbital admixture in the Cd(1-x)Mn(x)S quantum dots may exhibit an approximately cubic increase with increasing the Mn concentration x from 0.001 to 0.15.

关键词: electron-paramagnetic-resonance;transition-metal impurities;atomic;screening constants;optical-properties;defect structures;scf;functions;crystals;ions;nanocrystals;semiconductor

SIF expressions for center cracked strip loaded by uniformly distributed stress acting on central portion of crack - Corrections of Chen's results - Response

International Journal of Fracture

关键词:

显微组织对X65～X70管线钢抗H2S性能的影响

张雁 , 蔡庆伍 , 谢广宇

腐蚀学报（英文）

通过扫描电镜（SEM）、透射电镜（TEM）等方法，研究了X65～X70级别管线钢在饱和H2S溶液中的氢致开裂行为，及不同显微组织、位错与析出对氢致开裂（HIC）的作用.结果表明：组织均匀的珠光体/铁素体型X65管线钢和铁素体/针状铁素体型X70管线钢均具有良好的抗H2S腐蚀性能；带状组织是裂纹萌生和扩展的主要途径；合金元素的弥散析出作用可以提高管线钢的抗硫化氢腐蚀性能.

关键词: 管线钢 , null , null

显微组织对X65～X70管线钢抗H2S性能的影响

张雁 , 蔡庆伍 , 谢广宇

腐蚀学报（英文） doi:10.3969/j.issn.1002-6495.2007.06.004

通过扫描电镜(SEM)、透射电镜(TEM)等方法,研究了X65～X70级别管线钢在饱和H2S溶液中的氢致开裂行为,及不同显微组织、位错与析出对氢致开裂(HIC)的作用.结果表明:组织均匀的珠光体/铁素体型X65管线钢和铁素体/针状铁素体型X70管线钢均具有良好的抗H2S腐蚀性能;带状组织是裂纹萌生和扩展的主要途径;合金元素的弥散析出作用可以提高管线钢的抗硫化氢腐蚀性能.

关键词: 管线钢 , 显微组织 , 带状组织 , 氢致开裂(HIC) , 硫化氢(H2S)

THEORETICAL STUDIES ON THE GYROMAGNETIC FACTORS FOR Fe(3+) IN ZnX (X = O, S, Se, Te)

Modern Physics Letters B

The gyromagnetic factors for Fe(3+) in ZnX (X = O, S, Se, Te) are theoretically studied from the perturbation formula of the g-factor for a 3d(5) ion in tetrahedra based on inclusion of both the crystal-field and the charge-transfer contributions. The related model parameters in the calculations are determined from the cluster approach in a uniform way. The g-shift Delta g (-g - g(s), where g(s) approximate to 2.0023 is the spin-only value) from the charge-transfer contributions is opposite (positive) in sign and much larger in magnitude as compared with that from the crystal-field ones. The importance of the charge-transfer contributions increases rapidly with increasing the covalency and the spin-orbit coupling coefficient of the ligand and thus exhibits the order of O(2-) < S(2-)

关键词: Crystal-fields and spin Hamiltonians;electron paramagnetic resonance;(EPR);Fe(3+);ZnX (X = O, S, Se, Te);spin-hamiltonian parameters;atomic screening constants;magnetic;semiconductor;paramagnetic resonance;electronic states;optical;spectra;local-structure;scf functions;ferromagnetism;impurities

国产X80管线钢的H2S应力腐蚀开裂行为

奚运涛 , 刘道新 , 蔡杭平 , 樊明峰 , 鲜宁

腐蚀学报（英文）

采用三点弯曲加载法，研究了国产X80管线钢及其焊接接头的抗H2S环境应力腐蚀开裂（SSCC）行为.结果表明，热影响区（HAZ）对应力腐蚀开裂最为敏感，主要是HAZ组织不均匀、晶粒粗大、硬度大，易引起局部腐蚀，从而导致该区SSCC敏感性高。母材的纵向和横向取样对H2S应力腐蚀不敏感，薄壁管材较厚壁管材有更好的H2S环境应力腐蚀抗力. 

关键词: X80钢 , null , null