材料期刊网

Hot Working Characteristics of CorrosionResistant Alloys G3 and 825

YU Man , LI Jingshe , TANG Haiyan , BAO Yaozong

钢铁研究学报(英文版)

The G3 and 825 alloys, with excellent combination of mechanical properties and corrosion resistance, can be used in hot, and acid environments. Thermal simulation tests were conducted on the alloys G3 and 825 in the THERMECMASTORZ simulator, at temperature between 1030 and 1300 ℃, with strain rate from 1 to 50 s-1 and strain ε=08. The variations of flow stress with deformation temperature and strain rate were presented. Change of alloy structure with hot deformation and effect of strain rate on alloy dynamic recrystallization have been studied through microstructure observation by OM, SEM and TEM. Moreover, hot plasticity characteristics of alloy were analyzed by temperaturereduction of area curves. The results showed that available hot working temperature for G3, G3Z and 825 was 1100 to 1240 ℃, 1130 to 1220 ℃ and 1050 to 1240 ℃, respectively. The reliable information on hot working in the alloy pilot production in steelwork is given.

关键词: corrosionresistant alloy; G3; 825; stressstrain curve; hot plasticity

Improved Nonlinear Equation Method for Numerical Prediction of Jominy EndQuench Curves

SONG Yuepeng , LIU Guoquan , LIU Shengxin , LIU Jiantao , FENG Chengming

钢铁研究学报(英文版)

Without considering the effects of alloying interaction on the Jominy endquench curves, the prediction results obtained by YU Baihai′s nonlinear equation method for multialloying steels were different from those experimental ones reported in literature. Some alloying elements have marked influence on Jominy endquench curves of steels. An improved mathematical model for simulating the Jominy endquench curves is proposed by introducing a parameter named alloying interactions equivalent (Le). With the improved model, the Jominy endquench curves of steels so obtained agree very well with the experimental ones.

关键词: Jominy endquench curve;nonlinear equation method;alloying interaction parameter;computer simulation

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

Molecular dynamics studies on vacancy-interstitial annihilation in silicon

Acta Physica Sinica

Molecular dynamics (MD) simulation is performed to study the vacancy-interstitial annihilation in crystalline silicon. We choose the Stillinger-Weber potential, which is commonly used for silicon, to describe the interaction between atoms. The system is relaxed under 300K and 1400K respectively. We have found that < 111 > is the preferred recombination direction and propose the presence of an energy barrier in the < 110 > direction. From the calculated value of energy barrier along < 110 > we give a reasonable explanation for the difference between Tang's and Zawadzki's data.

关键词: molecular dynamics;vacancy and interstitial;diffusion;point-defects;diffusion;mechanisms

ELECTRONIC-PROPERTIES OF ONE-DIMENSIONAL QUASI-LATTICES

Zeitschrift Fur Physik B-Condensed Matter

we study the on-site model of a new class of one-dimensional quasiperiodic lattices, for which the substitution rules are B --> BA, and A --> BAB. By means of the renormalization-group approach, a interesting multifractal spectral behavior has been found, which has been confirmed by numerical simulation. A Cantor-like energy spectra is obtained by using the Kohmoto-Kadanaff-Tang (KKT) renormalization-group method. Three kinds of wave-function behavior (extended, localized, and intermediate states) are definitely found.

关键词: energy-spectrum;quasiperiodic lattices;localization problem;trace;maps;fibonacci;quasicrystal;systems;tilings

不同烷基酰亚胺的合成及对镥的萃取

刘峙嵘 , 周利民 , 李传茂 , 江小昌

稀有金属 doi:10.3969/j.issn.0258-7076.2006.03.021

合成了7种同一系列新型酰亚胺类萃取剂,并运用元素分析、核磁共振、红外光谱、紫外光谱等测试手段对其物化指标进行了表征.萃取性能表明,烷基酰亚胺萃取稀土镥的能力与骨架空间结构有关.直链烷基酰亚胺萃取镥的能力大于相应的支链烷基酰亚胺,而且随链长的增长萃取能力不断增强.利用斜率法,采取直线线性回归求得镥(Ⅲ)与萃取剂基本上以1:2交换.相同条件下,7种酰亚胺类萃取剂分配比的大小顺序为DOI＞DDI＞DHI＞HAI＞HIBI＞DBI＞BIBI.

关键词: 烷基酰亚胺 , 合成 , 镥 , 萃取

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

铜催化炔丙醇酯与β-羰基膦酸酯的不对称[3+2]环加成反应合成手性膦酰化2,3-二氢呋喃

陈修帅 , 侯传金 , 李晴 , 刘彦军 , 杨瑞丰 , 胡向平

催化学报 doi:10.1016/S1872-2067(16)62488-9

手性2,3-二氢呋喃衍生物是一类重要的杂环化合物,广泛存在于天然产物和生物活性分子中.它们也经常被用于手性四氢呋喃化合物的不对称合成.因此,人们发展了很多合成手性2,3-二氢呋喃化合物的方法,如有机小分子催化的多米诺迈克尔-烷基化反应、“中断的”Feist-Bénary反应或改进的 Feist-Bénary反应.此外,过渡金属催化的手性2,3-二氢呋喃的不对称合成在近些年引起了人们的极大关注. Ozawa等通过 Pd-催化2,3-二氢呋喃的动力拆分方法获得了手性2-芳基-2,3-二氢呋喃. Evans发展了一种 Sc-催化联烯硅和乙醛酸乙酯的[3+2]环加成反应合成手性2,3-二氢呋喃的方法.最近, Fu和 Tang等发展了 Cu催化烯酮和重氮化合物的[4+1]环加成反应合成手性2,3-二氢呋喃的方法.在 Nishibayashi和 van Maarseveen的开创性工作之后, Cu催化的不对称炔丙基转化反应取得了很大的进展.最近,我们发展了一类新的三齿手性 P,N,N-配体,在 Cu催化不对称炔丙基取代、脱羧炔丙基取代、[3+2]、[3+3]和[4+2]环加成反应中表现出优秀的对映和非对映选择性.其中,我们发现采用 Cu催化炔丙醇酯和β-酮酯的[3+2]环加成反应,能高对映选择性地获得手性2,3-二氢呋喃.我们设想,采用β-羰基膦酸酯代替β-酮酯,通过这种 Cu催化[3+2]环加成反应,将可以合成一类具有重要生物活性的手性膦酰化2,3-二氢呋喃化合物.基于这种设想,本文使用手性 P,N,N-配体,通过 Cu催化炔丙醇酯与β-羰基膦酸酯的不对称[3+2]环加成反应,以很好的收率和最高92% ee的对映选择性获得了一系列光学活性的膦酰化2,3-二氢呋喃化合物.我们以炔丙醇酯1a与β-羰基膦酸酯2a为标准底物,优化了反应条件,考察了配体、Cu盐、碱和反应温度等对反应收率和对映选择性的影响.我们确定了最佳的反应条件：以4b为配体,以 Cu(OTf)2为铜盐,以t-BuOK为碱,以 MeOH为溶剂,–20oC反应24 h.在此条件下,我们对β-羰基磷酸酯2的适用范围进行了考察.结果表明,各种苯基取代的β-羰膦磷酸酯均能得到很好的收率和对映选择性.苯环上取代基的空间效应对反应的对映选择性影响不大,但对反应收率影响较大,与相应3-取代或4-取代底物相比较,2-取代的底物获得的收率较低.苯环对位取代基的电子效应对反应的影响不大,给电子基或吸电子基的底物,均得到了较好的收率和对映选择性.杂环取代的底物同样适用于该反应,以90%的收率和89% ee的对映选择性获得了相应的[3+2]环加成产物.对于烷基底物,虽然反应的产率略低,但是得到了高达92% ee的产物.此外,我们对炔丙醇酯底物的适用范围也进行了考察.结果表明,该体系对于各种取代的炔丙醇酯底物均可以获得较高的收率和良好的对映选择性.总之,本文发展了一种铜催化炔丙醇酯与β-羰基膦酸酯的不对称[3+2]环加成反应的方法,成功合成了手性膦酰化2,3-二氢呋喃化合物.通过使用一个结构刚性的酮亚胺三齿 P,N,N-配体,以很好的收率和最高92% ee的对映选择性获得了一系列光学活性的膦酰化2,3-二氢呋喃化合物.

关键词: 铜 , 不对称合成 , 3+2环加成 , β-羰基膦酸酯 , 膦酰化 2,3-二氢呋喃