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工艺因素对319铝合金热分析特征值的影响

佟媛媛 , 华勤

上海金属 doi:10.3969/j.issn.1001-7208.2010.03.011

运用热分析技术研究了冷却曲线特征值与319铝合金中化学成分之间的关系,并进行回归分析.结果表明,在不考虑工艺因素的情况下,试样的硅含量与α-Al枝晶生长回升温度TαDENG之间的相关性最大,相关系数r为-0.65,以硅含量可预测α-Al枝晶生长回升温度.在浇注过程中,冷却速度与α-Al枝晶生长回升温度TαDENG密切相关,相关系数为r=-0.72.在相同的冷却条件下,铝合金的浇注温度和浇注量对冷却速度有明显的影响,因此,可以通过调整浇注温度和浇注量,控制铝合金的冷却速度,进而也可预测铝合金中α-Al枝晶生长回升温度TαDENG.

关键词: 319铝合金 , 热分析 , 特征值 , 浇注工艺

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

Bulk and surface half-metallicity: Metastable zinc-blende TiSb

Journal of Applied Physics

Motivated by the recent experimental fabrication of half-metallic MnSb and CrSb thin films with metastable zinc-blende structure [Aldous et al. Phys. Rev. B 85, 060403(R) (2012); Deng et al. J. Appl. Phys. 99, 093902 (2006)], we investigate the structural, electronic, and magnetic properties of TiSb in both ground-state NiAs and metastable zinc-blende phases by using the first-principles calculations. It is shown that the ground-state NiAs phase is metallic and nonmagnetic, but the metastable zinc-blende phase exhibits half-metallic ferromagnetism with a magnetic moment of 1.00 mu(B) per formula unit. We also reveal that the half-metallicity in bulk ZB TiSb is lost at the Sb-terminated (001) surface due to the appearance of surface states within the gap of the minority-spin channel, but the Ti-terminated (001) surface retains the bulk half-metallicity, which makes ZB TiSb a promising candidate for the possible epitaxial growth of half-metallic thin films or multilayers on semiconductor substrates for spintronic applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739744]

关键词: room-temperature ferromagnetism;molecular-beam epitaxy;crsb;cras;spintronics;state;mnas

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