材料期刊网

Rheological Behavior of Semi-Solid AZ91D Alloy

Weimin MAO , Zisheng ZHEN , Shijian YAN , Xueyou ZHONG

材料科学技术（英文）

The rheological behavior and microstructure of semi-solid AZ91D was studied using a Couette type viscometer. The results show that the apparent viscosity of semi-solid AZ91D increases with the cooling rate increasing when it is continuously cooled and mechanically stirred and the empiric relation of the apparent viscosity with the cooling rate and solid fraction at shearing rate 93.7 s-1 is expressed as η=[0.66-0.63e(-ε3.01)]e (fs/0.14), and with the shearing rate and solid fraction at cooling rate 4ºC/min is shown as η=0.55e(fs/0.11- /87.59), as well as the cooling rate and shearing rate have an important effect on the microstructure of the semi-solid AZ91D alloy slurry, and decreasing the cooling rate and increasing the shearing rate are favorable to the nondendritic evolution of the primary grains.

关键词: Rheological behavior , null , null

Cu-Zr/ZrN薄膜体系的电阻率和纳米压入研究

白宣羽 , 汪渊 , 徐可为

稀有金属材料与工程

采用磁控溅射方法在Si(111)基片上沉积Cu-Zr/ZrN薄膜体系作为扩散阻挡层.通过比较Cu-Zr/ZrN薄膜体系和三元非晶(Mo,Ta,W)-Si-N的电阻率,同时比较Cu-Zr/ZrN薄膜体系和Ta,YaN的硬度,说明作为扩散阻挡层的材料的选取,应从整体性能上考虑,而不能仅仅考虑热稳定性等单一指标.

关键词: 非晶 , 电阻率 , 纳米压入 , 硬度

Studies of the g factors and the local structure for Ni3+in LaAl0.9Ni0.1O3, La0.75Y0.25Al0.99Ni0.01O3 and YAl0.9Ni0.1O3

Radiation Effects and Defects in Solids

The electron paramagnetic resonance g factors and the local structure for Ni3+ in LaAl0.9Ni0.1O3 (LAN), La0.75Y0.25Al0.99Ni0.01O3 (LYAN) and YAl0.9Ni0.1O3 (YAN) are theoretically studied from the perturbation formulas of the g factors for a 3d7 ion of low spin (S = 1/2) in tetragonally elongated octahedra. In these formulas, the contributions to the g factors from the tetragonal distortion, characterized by the tetragonal field parameters Ds and Dt are taken into account. According to the calculations, the ligand octahedra around Ni3+ are suggested to suffer 2% relative elongation along the [001] (or C4) axis due to the Jahn-Teller effect.

关键词: defect structures;electron paramagnetic resonance;crystal-fields and;spin Hamiltonians;Ni3+;LaAlO3;LaYAlO3;YAlO3;atomic screening constants;optical-spectra;paramagnetic-resonance;superconducting tapes;lattice-distortions;superposition model;scf;functions;cr3+ ions;crystals;epr

非微扰QCD和核遮蔽效应对K因子的影响

智海素 , 侯召宇

原子核物理评论 doi:10.3969/j.issn.1007-4627.2006.01.002

考虑非微扰量子色动力学物理真空夸克凝聚效应,计算了碳核与碳核在质心系能量分别为630和200 GeV时碰撞Drell-Yan过程的K因子,以及加入核遮蔽因子后非微扰效应对K因子的影响,并把计算结果与没有考虑夸克凝聚非微扰效应的K值进行了对比.结果表明,非微扰效应和核遮蔽效应对K因子影响很小.

关键词: K因子 , Drell-Yan过程 , 夸克凝聚 , 非微扰量子色动力学 , 核遮蔽效应