材料期刊网

ON THE BURN RESISTANCE OF Ti-35V-15Cr-0.05C TITANIUM ALLOY

G.P. Li , D. Li , Y. Y. Liu , Q.J. Wang , S.X. Guan , and Q.C. Li (Institute of Metal Research , The Chinese Academy of Sciences , Shenyang 110015 , China)(School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , China)

金属学报(英文版)

The Ti-35V-15Cr-0.05C (wt% is a new nonburning titanium alloy. The test for alloy combustibility was carried out by using CO2 laser. A 430 watt and 6mm diameter laser spot impinges directly on the sample within normal atmospheric pressure and temperature. The results show that the ignition time of the nonburning titanium alloy is the longest in the eight examined titanium alloys, and is 3.5 times that of TC4 alloy. The ignition tempeerature of the nonburning alloy is 2991° C, and is higher than that of TC4 alloy by 1976°C. On the condition of high tempeerature and rich oxygen,the surface of alloy forms a melting layer which plays roles of oxygen insulation, heat insulation and burning products insulation. This is the mechanism of combustion resistance.

关键词: Ti-35V-15Cr-0.05C (wt%) nonburning titanium alloy , null

大爆炸核合成相关的8Li(d, p)9Li反应截面测量

李志宏 , 柳卫平 , 白希祥 , 郭冰 , 连钢 , 颜胜权 , 王宝祥 , 陆昀 , 曾晟 , 苏俊

原子核物理评论 doi:10.3969/j.issn.1007-4627.2005.01.006

利用8Li次级束测量了质心系能量7.8 MeV 2H(8Li, 9Li)1H反应的角分布, 导出了8Li(d, p)9Li反应的天体物理S因子及9Li→8Li+n虚衰变的渐近归一化系数.

关键词: 8Li(d,p)9Li反应 , 角分布 , 天体物理S因子 , 渐近归一化系数

HIGH-RESOLUTION ELECTRON-MICROSCOPY STUDY OF DEFECTS IN AN FCC PHASE FORMED BY INGOT CASTING IN AL-LI-CU-MG ALLOYS

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

An fc.c. phase designated Y has been studied by means of high resolution electron microscopy (HREM) and transmission electron microscopy in Al-Li-Cu-Mg alloys. HREM observation and electron diffraction patterns show the intergrowth of another Franker-Kasper domain (designated D) with the Y phase. The D domain can grow on both the (001) and the (111) planes of the Y phase. The orientation relationships between the D domain and the Y phase are [110]Y//[100]D, (111BAR)Y//(001)D and [110]Y//[100]D, (001)Y//(010)D.

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Proposed relationship between the exponents gamma and eta at liquid-vapour critical point via the dimensionality d

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

Corrosion resistance of Mg-8.8Li alloy compared with AZ91

Corrosion Engineering Science and Technology

The superlight Mg-Li alloys exhibit good formability but poor corrosion resistance due to the alloying of lithium. In this paper, the corrosion behaviour of Mg-8.8Li alloy was investigated by electrochemical measurements, corrosion morphology observations and weight loss determination. The results indicate that Mg-8.8Li alloy displays worse corrosion resistance than AZ91D alloy in the early stages of corrosion. However, the corrosion resistance of AZ91D alloy declines and becomes worse than Mg-8.8Li alloy with increasing exposure time. In addition, it is found that a 250 degrees C annealing treatment has a detrimental effect on the corrosion resistance of Mg-8.8Li alloy.

关键词: Corrosion;Magnesium alloy;Mg-Li;AZ91D;Annealing treatment;mg-3nd-0.2zn-0.4zr wt.percent alloy;magnesium alloy;mechanical-properties;behavior;microstructures

YNLL新型干法水泥2500 t/d生产线的热工检测与分析

赵国华 , 齐砚勇 , 潘玉峰

硅酸盐通报

对YNLL水泥厂2500 t/d生产线进行热工标定并分析,系统烧成热耗为3889 kJ/kg.cl,高于全国平均水平.高温风机拉风偏大,一级筒出口温度为370℃,偏高.篦式冷却机效果欠佳,AQC抽风量偏高,直接影响了熟料质量和余热发电量,热回收效率偏低.经过改进和优化,熟料产能提高为2600 t/d.该生产线系统还有比较大的潜力,熟料产量还有可能进一步提高,热耗及电耗均可能明显下降.

关键词: 热工标定 , 新型干法水泥 , 篦冷机

Studies of EPR parameters for Mn5+-doped Li3PO4 and Li3VO4 crystals

Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy

The EPR parameters (zero-field splitting D and g factors g(vertical bar vertical bar), g(perpendicular to)) of Mn5+-doped Li3PO4 and Li3VO4 crystals are calculated from the complete high-order perturbation formulas based on a molecular orbital scheme for a 3d(2) ion in tetragonal MX4 clusters. These formulas include not only the contribution coming from crystal-field excitations, but also that arising from charge-transfer excitations (which is discarded in crystal field theory). The calculated results are in reasonable agreement with the observed values. The contributions to EPR parameters coming from the charge-transfer excitations are comparable with those arising from the crystal-field excitations. It appears that for a high valence state 3d(n) ion in crystals, the reasonable explanations of EPR parameters should take the contributions due to both crystal-field and charge-transfer excitations into account. (c) 2006 Elsevier B.V. All rights reserved.

关键词: electron paramagnetic resonance (EPR);crystal;and ligand-field theory;charge transfer mechanism;Mn5+;Li3PO4;Li3VO4;atomic screening constants;oxo coordination;phase-transition;scf;functions;laser action;complexes;pressure;forsterite;covalency;ions

LNZL水泥厂2500t/d生产线的热工检测与分析

曹华夏 , 毕金栋 , 李昌勇

硅酸盐通报

对LNZL水泥厂2500 t/d生产线进行热工标定并分析,该厂熟料产量超过设计产量28.96％,达到3224.1t/d.系统烧成热耗为3302.6kJ/kg熟料,低于全国平均水平,一级筒出口温度为334℃,稍有些偏高;系统的分离效率为91.49％,出预热器飞灰量偏高,还有明显的改善空间.篦式冷却机效果欠佳,直接影响了熟料质量和余热发电量,热回收效率也偏低.该生产线系统还有比较大的潜力,如经过改进和优化,熟料产能还有可能进一步提高,热耗及电耗均可明显下降.

关键词: 热工检测 , 水泥生产线 , 运行情况

Energy levels of the d*(8) electron and d*(2) hole system

Physical Review B

In the investigation of the optical and magnetic properties of the semiconductors containing transition-metal ions, the one-electron orbital cannot be treated with a pure d orbital because of a strong covalence. This paper presents the energy matrix of the d*(8) and d*(2) (d* means a modified d function) system, in which the covalence is described by two covalent factors. The differences between the matrix diagonal elements of the t(2)(m)e(n) term of the d*(8) system and the t(2)(6-m)e(4-n) term of the d*(2) system vary with m and n. The d(N) electron system can be explained with the d(10-N) hole system because the difference between the energy matrix of the d(N) and d(10-N) systems has a fixed value. However, this kind of simple relation does not exist for the d*(N) and d*(10-N) systems when the covalence is considered. A numerical calculation shows that the variation of the energy levels with the covalence for Ni2+ in the d*(8) electron system is larger than that in the d*(2) hole system. The calculated energy levels obtained from the d*(8) matrix are in good agreement with the experimental data of the Ni2+ ion for ZnS:Ni and ZnSe:Ni. This suggests that the d*(8) electron system instead of the d*(2) hole system should be used in the investigation of optical and magnetic properties of semiconductor containing Ni2+ ions.

关键词: zns-ni;absorption;vanadium;impurities;spectra;ions

Investigation of the local structure of the tetragonal Ni2+-V-Li center in LiCl:Ni2+ crystal from epr parameters

Radiation Effects and Defects in Solids

The zero-field splitting D and the g factor g(parallel to), Delta g (= g(parallel to) - g(perpendicular to)) of the tetragonal Ni2+-V-Li center in LiCl:Ni2+ crystal have been studied from the high-order perturbation formulas of these EPR parameters for d(8) ions in tetragonal symmetry. On the basis of this, the local structure of this tetragonal center is determined and the negative sign of the zero-field splitting D of the crystal is obtained.

关键词: electron paramagnetic resonance;local structure;crystal-field theory;Ni2+;LiCl;spin-hamiltonian parameters;superposition-model;ni(ii) compounds;ground-state;ions;symmetry;halides;cr3+