热处理方法改善CdZnTe晶体性能研究

对电阻率为10^3-6Ω·cm的In掺杂Cd0．9Zn0．1Te晶片在Te气氛和Cd／Zn平衡蒸汽压下进行了热处理，对电阻率为10^8-9Q·cm的非掺杂晶片则在In气氛和Cd／Zn平衡蒸汽压下进行了热处理。结果表明，In掺杂Cd0．9Zn0．1Te晶片经处理后电阻率可提高3个数量级。非掺杂晶片在In气氛中热处理可很容易地改变导电类型，在热处理温度700℃，In分压6．1×10^-4Pa，退火时间达48h后，电阻率可以提高到2．6×10^9Ω·cm。     

利用可控In气氛下热处理工艺制备Cd0．9Zn0．1Te：In

利用控制In气氛下的热处理工艺成功地制备了CdZnTe：In。不同In压下（Cd，Zn分压保持在平衡分压）的热处理实验结果表明：热处理后样品的电阻率可从6．75×10^5Ω·cm提高到10^8～10^1010Ω·cm；并且随着In压的增加，导电类型逐渐由p型转变为n型。热处理后样品的电阻率变化特征可以由In的扩散和施主缺陷InCd、受主缺陷VCd之间的补偿作用来很好地解释。利用扩散理论建立了CdZnTe：In的电阻率物理模型。利用热处理后样品的电阻率数据，计算了在873，973和1073K时In原子在CZT晶体中的有效扩散系数DIn，分别为3．455×10^-11，2．625×10^-10和5．17×10^-9cm^2／s。将扩散数据经过拟合后得到了DIn的表达式：1．35exp（-1．85eV／kT）cm^2／s（873～1073K）。     

益仁堂进入稀土高新区建20kt／a高纯铝项目

内蒙古益仁堂集团从2008年5月起至2012年5月为止的这段时间内,将在包头稀土高新区内建设产业链完整的高纯铝项目．总投资22亿元．占地约64×10^4m^2：20kt／a高纯铝项目,占地面积10×10^4m2;30kt／a电子光箔项目,占地面积16．7×10^4m^2：6．3kt／a腐蚀化成箔项目,占地面积37．3×10^4m^2。     

汨罗龙舟铝业公司引进高技术均匀化炉

汨罗龙舟铝业有限公司从美国塞科沃克（Seco／Warwick）公司引进1台高技术硬合金圆锭均匀化处理炉,该炉是由塞科沃克（天津）工业炉公司（Seco／Warwick（Tianjin）Industrial Fumace Co．Ltd．）制造的。龙舟铝业公司是一家以废铝为原料生产可热处理强化的2×××,6×××系及7×××系硬铝合金挤压圆锭的企业,     

铝塑复合板2008年产量可达2.6亿m^2

铝塑复合板是一种公认的良好建筑材料,集铝材与塑料的优点于一体,既洁净卫生,又经久耐用。中国是全球最大的铝塑复合板生产国、消费国和出口国。截止到2007年年末全国约有铝塑复合板生产企业210多家．总生产能力约5×10^8m^2,2007年的产量达到2．2×10^8m^8,2008年的产量有望达到2．6×10^8m^2。     

钛在航空领域的用量将得到提升

有色金属行业分析师认为,商用飞机的用钛量将以平均每年9．1％的速度增长,至2018年达到7．87×10^-4t,飞机机身用钛量会超过发动机用钛量。总部位于克利夫兰的Northcoast Research Holdings公司的Lloyd O’Carroll分析师,最近在一份报告中指出：2014年世界商用飞机用钛量为5．56×10^4t（1．225×10^8磅）,到2018年,用钛量将增长到7．87×10^4t（1．736×10^8磅）;这期间机身用钛量的复合年增长率为11％,而发动机用钛量的复合年增长率为6．7％;从波音787及空客A350的生产中可以发现,机身用钛量的增长速度高于发动机。     

12CAO·7Al2O3和γ-2CaO·SiO2混合物相的合成和溶出性能研究

本文研究了CaO的加入量、合成温度、保温时间和出炉温度对合成产物物相的影响,结果发现：当CaO2Al2O3：SiO2为2．38：1：0．77,合成温度1500℃,保温时间30min和出炉温度100℃时可获得只含有12CAO·7Al2O3和γ-2CaO·SiO2且氧化铝溶出性能较好的物料。采用二次回归正交试验法对读物料进行了溶出性能的研究,详细考察了其受碳钠浓度、氧化铝浓度、溶出温度、溶出时间和液固比的影响规律,得到的回归方程在0．01水平上高度显著,且方程回归值与试验值的相对误差不超过3％,回归方程的教学表迭式为：氧化铝溶出率Y=-3．094×100Nc^2-4．049×10^-5fT＋5．853×10^-3Nc＋3．192×10^-3t＋4．888×10^-3T＋5．183×10^-2L／S-5．99×10^-3．     

钇离子注入AZ31镁合金的氧化行为

研究了AZ31镁合金在钇离子剂量为5×10^16，1×10^17及5×10^17ions／cm^2注入条件下的氧化性能。纯氧气氛、500℃下的氧化实验结果表明，钇离子注入能提高AZ31镁合金的抗氧化性能，而且随着注入剂量的增大，合金表面抗氧化性能提高越大。俄歇电子能谱（AES）和X光电子能谱（XPS）分析表明：钇离子注入以后，在镁合金表面形成了具有双层结构的氧化层，外层主要由MgO组成，而内层主要由Y2O3，MgO构成。这一新形成的氧化层有利于提高AZ31镁合金的抗氧化性能。     

SPS法制备的赝二元合金（Ga2Te3）x-（Bi0．5Sb1．5Te3）1-x（x=0～0．2）电学性能

采用放电等离子烧结（SPS）方法制备了赝二元合金（Ga2Te3）（Bi0.5Sb1.5Te3）1-x（x=0—0．2），并研究其电学性能。结果表明，在318K时（Ga2Te3）x-（Bi0.5Sb1.5Te3）1-x（x=0．1）合金的电导率为3．7×10^4Ω^-1·m^-1，是三元合金Bi0.5Sb1.5Te3的2倍，而Seebeck系数没有明显下降。从所测得的a和σ值可知，赝二元（Ga2Te3）x-（Bi0.5Sb1.5Te3）1-x（x=0．1）合金的功率因子最大，为2．1×10^-3（W·K^-2·m^-1），是三元Bi0.5Sb1.5Te3合金的1．5倍。     

真空熔炼AZ91镁合金过程中Mg元素的蒸发行为

在真空Ar气氛中熔炼AZ91镁合金，测定了不同精炼温度下Mg元素的蒸发速率。结果表明，随着精炼温度的升高，Mg元素的蒸发量增大。通过计算可知，Mg的蒸气压是Al的10^9倍，是Zn的46倍，因此主要是Mg的蒸发而导致合金其他元素含量升高。XRD分析表明，蒸发物是Mg元素。结合Mg元素的蒸发机制，在该试验条件下推导出Mg元素蒸发率的计算公式以及Mg元素的表观传质系数、蒸发率与精炼温度的关系，计算得出Mg元素蒸发率为0．86×10^-3-1．35×10^3g／cm^2·s，Mg元素的表观传质系数在2×10^-5-24×10^-5cm／s范围内。     

单晶体Cd1-xMnxTe中的法拉第旋转

室温下测量了本实验室生长的Cd0.8Mn0.2Te和Cd0.9Mn0.1Te单晶体的法拉第旋转谱.通过提高布里渊区中心L点的能隙值(E1)改进了法拉第旋转的多振子模型.用改进的模型拟合实验结果,得到Cd0.8Mn0.2Te和Cd0.9Mn0.1Te单晶体布里渊区中心F点的能隙值(E0)分别为1.804 eV和1.667 eV.该E0值比以往任何研究都更接近于计算值.     

Photocatalytic activity of cation(Mn) and anion(N) substitution in LaCoO_3 nanoperovskite under visible light

LaCoO₃ compound and novel photocatalysts of LaCo_0.8Mn_0.2O₃ and N-doped LaCoO₃ were synthesized by sol-gel method.The structure,morphology,size of particles and optical properties of the obtained powders were characterized by X-ray diffractometer(XRD),scanning electron microscopy(SEM) and ultraviolet-visible(UV-Vis)(DRS mode) spectroscopy.The perovskite structure obtained for all the prepared samples and doping Mn and N do not change the pero...     

Gamma Irradiation Effects in InBi_(0.8) Te_(0.2) Crystals Grown by Horizontal Directional Freezing

The high-energy gamma-ray irradiation treatment using Co-60 isotope offers the possibility of engineering mechanical and optoelectronic properties of In Bi0.8Te0.2crystals. Tellurium-doped indium bismuthide(In Bi) crystals were prepared by horizontal directional freezing technique. Dose-dependent modifications in structure, composition and surface topographical features have been analyzed by X-ray powder diffraction, X-ray energy-dispersive analysis, transmission electron and atomic force microscopy, respectively. Dielectric constant and dielectric loss were found to increase with the cumulative dose of radiation, and a shift in the ferroelectric transition temperature(Tc) from 405 to 410 K was observed for25 k Gy. Upon irradiation, there is an enhancement in microhardness(HV), yield stress(ry) and stiffness constant(C11).The optical transmittance was decreased by 12.45%, resulting in a reduction in the optical band gap from 0.210 e V to0.198 e V. These results indicate the suitability of In Bi0.8Sb0.2crystals for low-wavelength infrared applications.     

Effects of Ce~(3+) doping on the structure and magnetic properties of Mn-Zn ferrite fibers

Ce3+-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition,structure,and magnetic properties of these ferrite fibers were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and vibrating sample magnetometer (VSM). The results show that Mn0.2Zn0.8Fe2-xCexO4 (x = 0-0.04) fibers are featured with an average grain size of 11.6-12.7 nm,with diameters ranging between 1.0 to 3.5 μm and a high ...     

Photoluminescence analysis of Cd0.8Mn0.2Te single crystal grown by the vertical Bridgman method

In this paper, the photoluminescence (PL) spectra were detected to characterize Cd_0.8Mn_0.2Te crystals grown by the vertical Bridgman method. Several monocrystalline (1 1 1) face plates with dimension of 30 × 40 × 2 mm³ were sliced from the as-grown Cd_0.8Mn_0.2Te ingot, where the PL analysis was conducted. The PL spectra revealed the neutral acceptor bound exciton (A⁰, X) peaks and the donor-acceptor pair (DAP) peaks. The activation energies derived from the temperature-dependent PL quenching of the (A⁰, X) peak was estimated to be 5.3 meV and 45.8 meV, which suggested the binding energy of excitons to acceptors at lower temperatures and the Auger recombination at higher temperatures. A relationship for the bandgap energy of Cd_0.8Mn_0.2Te as a function of temperature ranging from 10 K to 300 K was obtained. The composition uniformity of the (1 1 1) face Cd_0.8Mn_0.2Te plates were analyzed with PL spectra, which shown that the variation of Mn concentration is within 0.012 mole fraction.     

Doping and annealing effects on ZnO:Cd thin films by sol-gel method

In this article, ZnO:Cd films were successfully deposited on glass substrates by a sol-gel technique. The influence of doping concentration and annealing temperature effects was carefully investigated. All films exhibited c-axis preferential orientation and optical transparency with visible transmittance >80%. The minimum room temperature resistivity of 0.0341 Ω cm was obtained with 10 at.% Cd doping under 600 °C annealing temperature. The optical band gap of ZnO:Cd film was reduced as Cd doping concentration increased, while the band gap increased with the increase of annealing temperature.     

Influence of indium doping on the properties of spray deposited CdS0.2Se0.8 thin films

Polycrystalline indium doped CdS_0.2Se_0.8 thin films with varying concentrations of indium have been prepared by spray pyrolysis at 300 °C. The as deposited films have been characterized by XRD, AFM, EDAX, optical and electrical resistivity measurement techniques. The XRD patterns show that the films are polycrystalline with hexagonal crystal structure irrespective of indium doping concentration. AFM studies reveal that the RMS surface roughness of film decreases from 34.68 to 17.76 with increase in indium doping concentration up to 0.15 mol% in CdS_0.2Se_0.8 thin films and further it increases for higher indium doping concentrations. Traces of indium in CdS_0.2Se_0.8 thin films have been observed from EDAX studies. The optical band gap energy of CdS_0.2Se_0.8 thin film is found to decrease from 1.91 eV to 1.67 eV with indium doping up to 0.15 mol% and increase after 0.15 mol%. The electrical resistivity measurement shows that the films are semiconducting with minimum resistivity of 3.71 × 10⁴ Ω cm observed at 0.15 mol% indium doping. Thermoelectric power measurements show that films exhibit n-type conductivity.     

高振实密度球形LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2粉末的合成及性能

以共沉淀法制备的球形Ni_(0.5)Co_(0.3)Mn_(0.2)CO_3粉末为前驱体,按一定的比例将碳酸锂与前驱体混合,然后采用高温固相法合成高振实密度球形LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2正极材料.该材料的振实密度达到2.60 g/cm~3,与商品化LiCoO_2的密度相当.SEM分析表明, LiNi_(0.5)Co_(0.3)Mn_(0.2)O_2正极材料与前驱体形貌有良好的继承性,均为理想的球形.XRD物相分析表明,在不同合成温度下的Li Ni_(0.5)Co_(0.3) Mn_(0.2)O_2产物均为具有α-NaFeO_2层状结构的纯相物质,在较高合成温度下所得材料的结晶度较高.电化学性能研究表明,在2.7～4.3 V的电压范围内,电池的放电比容量在0.2C倍率下为168.1 mA-h/g,在1C倍率下为157.6 mA-h/g;经50次循环后,两种放电条件下的电池容量保持率分别为95.1%和97.2%,显示出良好的电化学性能.     

Synthesis and Properties of Monodisperse Superparamagnetic Mg_（0.8）Mn_（0.2）Fe_2O_4 Nanoparticles Using Polyol Reflux Method

Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol(DEG) used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction(XRD) and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.