李国平
钢铁
253MA是在21Cr-11Ni不锈钢的基础上,通过N合金化和添加稀土元素Ce开发的耐热纯奥氏体不锈钢.由于该钢种的熔点与碳钢相比偏低,钢液的流动性差,因此如何解决氮气合金化、稀土添加等问题,是冶炼过程中的工艺难点.通过对不同稀土加入方式、过程脱氧、夹杂物控制以及精确控N模型等的相关参数的研究,成功完成了253MA的冶炼连铸,为生产板材创造了良好的条件.
关键词:
稀土加入工艺
,
氮合金化
,
不锈钢
李国平
钢铁
253MA是在21Cr11Ni不锈钢的基础上，通过N合金化和添加稀土元素Ce开发的耐热纯奥氏体不锈钢。由于该钢种的熔点与碳钢相比偏低，钢液的流动性差，因此如何解决氮气合金化、稀土添加等问题，是冶炼过程中的工艺难点。通过对不同稀土加入方式、过程脱氧、夹杂物控制以及精确控N模型等的相关参数的研究，成功完成了253MA的冶炼连铸，为生产板材创造了良好的条件。
关键词:
稀土加入工艺;氮合金化;不锈钢
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
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
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
Physics and Chemistry of Liquids
In earlier work, Ma [S.K. MA, Phys. Rev. Lett., 29, 1311 (1972)] has studied the critical exponents and for charged and neutral Bose gases. Here we use the result of Ma, valid for general dimensionality d but only to O(m-1), where m is the number of components of the Bose field, to write a relation between (d) and (d) to O(m-1). This then motivates, but now for the Ising model, a relationship between the critical exponents and , via the dimensionality d. We finally demonstrate a connection between the two renormalisation group eigenvalues yt and yh, via the critical exponent with a dimensional dependence.
关键词:
critical exponents;Ising model;dimensionality
车玮玮
,
苏希玉
,
王梅
低温物理学报
对比研究了Minimum模型中d-波配对和扩展s-波配对的基本性质.结果表明,超导序参量按类BCS关系随温度变化,重整化参数t对超导有抑制作用,当t足够大时,超导消失,系统进入正常金属相.此外,讨论了超导序参量随不同参量的变化关系.对于d波,系统有稳定态;而对于扩展s波,系统则没有稳定态.
关键词:
Minimum模型
,
d-波
,
扩展s-波
,
铁基超导体
