材料期刊网

Effect of CuO Addition on the Sintering Behavior and Electrical Conductivity of 3Y-TZP

Ahmed A.Hassan , Omar Abdelal A.

材料科学技术（英文）

Yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) doped with CuO was prepared, to get two compositions, 0.3 and 1 mole fraction CuO, respectively. The dilatometric study of the samples showed sintering to be improved for the samples doped with 0.3 mole fraction CuO, and to be deteriorated for the samples doped with 1 mole fraction CuO. The 1 mole fraction CuO doped 3Y-TZP showed higher tetragonal/monoclinic phase transformation which was accompanied by grain growth. The electrical conductivity decreased with the addition of CuO.

关键词: Y2O3 , D. , Sintering , aids , C.electrical , co

新型镍基高温合金在模拟燃煤锅炉环境中的腐蚀

赵双群 , 谢锡善 , Gaylord , D. , Smith

金属学报

在人工合成的煤灰/烟气环境中研究了一种新型镍基高温合金550℃和700℃的腐蚀行为和腐蚀机理．结果表明, 合金在550℃发生了不均匀的点蚀, 表面形成了一层很薄的Cr2O3膜, 腐蚀按照硫化机制发展．合金在700℃腐蚀时, 初期发生了氧化和硫化腐蚀, 表面生成了保护性的氧化膜, 并有内硫化物析出．由于合金表面生成CoO并在表面形成熔融态硫酸盐而逐渐进入加速腐蚀阶段, 使合金遭受严重的低温热腐蚀．腐蚀产物外层为疏松的混合尖晶石化合物, 内层为致密的氧化物层, 在腐蚀层、腐蚀层与基体界面和Cr元素贫化区内分布着硫化物．合金耐腐蚀性能的迅速退化是合金表面Co及其氧化物在混合熔盐中的溶解所致.

关键词: 镍基高温合金 , coal ash-flue gas , low temperature hot corrosion

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

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

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

Influence of phytic acid concentration on performance of phytic acid conversion coatings on the AZ91D magnesium alloy

Materials Chemistry and Physics

In this study, the phytic acid conversion coating, a new environmentally friendly chemical protective coating for magnesium alloys, was prepared. The influences of phytic acid concentration on the formation process, microstructure, chemical state and corrosion resistance of the conversion coatings on AZ91 D magnesium alloy were investigated by means of weight gain measurement, field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS), respectively. And the depth profile of all elements in the optimal conversion coatings was analyzed by auger electron spectroscopy (AES). The results show that the growth, microstructure, chemical state and corrosion resistance of the conversion coatings are all obviously affected by the phytic acid concentration. The concentration of 5gl(-1) corresponds to the maximum weight gain. The main elements of the coating are Mg, Al, O, P, and C, which are distributed gradually in depth. The functional groups of conversion coatings formed in higher concentration phytic acid solution are closer to the constituent of phytic acid than those formed in lower concentration phytic acid solution. The coatings formed in 1-5 gl(-1) are integrated and uniform. However, those formed in 20-50 gl(-1) have some micro-cracks on the (x phase. The coating formed in 5 gl(-1) has the best corrosion resistance, whose open circuit current density decreases about six orders than that of the untreated sample, although the coatings deposited in 1-20 gl(-1) can all improve the corrosion resistance of AZ91 D. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

关键词: concentration;magnesium alloys;phytic acid;conversion coatings;corrosion-resistance;chromatography;behavior;copper;mg

液晶材料与3D显示

张兴 , 郑成武 , 李宁 , 周兴丹 , 李正强 , 华瑞茂

液晶与显示 doi:10.3788/YJYXS20122704.0448

介绍了3D显示的基本原理,重点介绍了目前3D显示的主流技术类型,包含了眼镜式3D技术以及裸眼式3D技术,其中眼镜式3D技术包含色差式3D技术、偏光式3D技术和主动快门式3D技术;裸眼式3D技术包含视差屏障式3D技术、柱状透镜式3D技术、指向光源式3D技术和多层显示式3D技术.阐述了各种3D显示技术的基本实现原理和应用领域、并对涉及液晶显示的几种3D技术的优缺点进行了对比.结合液晶材料的特点与3D液晶显示的实际要求,阐述了3D液晶面板对液晶材料快速响应方面的要求,以及液晶透镜对液晶材料光学各向异性参数的要求.

关键词: 3D显示 , 眼镜式3D显示 , 裸眼式3D显示 , 液晶材料

COMPARISON OF FATIGUE AND CREEP BEHAVIOR BETWEEN 2D AND 3D-C／SiC COMPOSITES

D.Han , S.R.Qiao , M.Li , J.T.Hou , X.J.Wu

金属学报(英文版)

The differences of tension-tension fatigue and tensile creep characters of 2D-C/SiC and 3D-C/SiC composites have been scrutinized to meet the engineering needs. Experiments of tension-tension fatigue and tensile creep are carried out under vacuum high temperature condition. All of the high temperature fatigue curves are flat; the fatigue curves of the 2D-C/SiC are flatter and even parallel to the horizontal axis. While the tension-tension fatigue limit of the 3D-C/SiC is higher than that of the 2D-C/SiC, the fiber pullout length of the fatigue fracture surface of the 3D-C/SiC is longer than that of the 2D-C/SiC, and fracture morphology of the 3D-C/SiC is rougher, and pullout length of the fiber tows is longer. At the same time the 3D-C/SiC has higher tensile creep resistance. The tensile curve and the tensile creep curve of both materials consist of a series of flat step. These phenomena can be explained by the non-continuity of the damage.

关键词: 2D-C/SiC , null , null

Surface properties of 3d transition metals

Philosophical Magazine

Using the projector augmented wave method within density functional theory, we present a systematic study of the layer relaxation, surface energy and surface stress of 3d transition metals. Comparing the calculated trends for the surface energy and stress with those obtained for 4d and 5d metals we find that magnetism has a significant effect on the surface properties. Enhanced surface magnetic moments decrease the size of the surface relaxation, lower the surface energy and surface stress, leading to compressive stress in Cr and Mn.

关键词: surface relaxation;surface energy;surface stress;magnetic transition;metals;density functional theory;full charge-density;initio molecular-dynamics;total-energy;calculations;augmented-wave method;ab-initio;electronic-structure;atomic volume;work function;basis-set;relaxation