Enthalpies of formation of Cd–Pr intermetallic compounds and thermodynamic assessment of the Cd–Pr system

In the present study standard enthalpies of formation were measured by reaction and solution calorimetry at stoichiometric compositions of Cd₂Pr, Cd₃Pr, Cd₅₈Pr₁₃ and Cd₆Pr. The corresponding values were determined to be −46.0, −38.8, −35.2 and −24.7 kJ/mol(at), respectively. These data together with thermodynamic data and phase diagram information from literature served as input data for a CALPHAD-type optimization of the Cd–Pr phase diagram. The complete composition range could be described precisely with the present models, both with respect to phase equilibria as well as to thermodynamic input data. The thermodynamic parameters of all intermetallic compounds were modelled following Neumann–Kopp rule. Temperature dependent contributions to the individual Gibbs energies were used for all compounds. Extended solid solubilities are well described for the low- and high-temperature modifications of Pr and also for the intermetallic compound CdPr. A quite good agreement with all viable data available from literature was found and is presented.     

基于ADAMS轴承转运机械手运动学分析仿真

利用UG建模软件对四自由度轴承转运机械手进行实体建模。采用笛卡尔坐标系,通过齐次坐标变换对四自由度轴承转运机械手建立运动学模型,并对轴承转运机械手进行正运动学和逆运动学求解。将机械手模型导入ADAMS中转化为虚拟样机进行运动学仿真,分析了四自由度轴承转运机械手仿真结果的运动规律曲线。仿真结果验证了四自由度轴承转运机械手运动学方程的正确性,并获得了机械手运动时施加在滚动滑车和悬臂横梁的作用力。     

In掺杂对Cd_(0.8)Mn_(0.2)Te巨法拉第效应的影响

常温下测量了Cd0.8Mn0.2Te晶片和多个掺In浓度不同的Cd0.8Mn0.2Te（以下简称Cd0.8Mn0.2Te：In）晶片的法拉第旋转谱和吸收边附近的透射光谱。结果表明,随着入射光子能量的增大,Cd0.8Mn0.2Te和Cd0.8Mn0.2Te：In的Verdet常数随之增大。掺In晶片的Verdet常数的变化与掺杂浓度有关：当光子能量在1．63～1．72eV范围内逐渐增加时,未掺In的测量值的变化范围是710～1820（°）／cm·T;当In浓度为8．96×10^16 atoms／cm^3时,Verdet常数增大到720-1960（°）／cm·T：当In浓度n分别为2．39×10^17,4．48×10^18 atoms／cm^3时,Verdet常数分别减小到660～1630,490-1090（°）／cm·T;当In浓度达到2．99×10^19 atoms／cm^3时,在1．63～1．70eV的光子能量范围内,Verdet常数减小到460～740（°）／cm·T。低掺In条件下,Verdet常数的增大是由于价带电子数增多,价带类P电子与Mn^2＋离子3d电子交换相互作用增强引起的;在高掺In量下,由于导带类s电子与Mn^2＋离子3d电子交换相互作用增强,导带能级分裂进一步减小,导致Cd0.8Mn0.2Te：In的Verdet常数减小。     

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。     

Synthesis of nanoscale multilayered ZrN/W2N multilayered coatings by magnetron sputtering

ZrN/W₂N multilayered coatings with nanoscale modulation period in an ultra-high vacuum rf magnetron sputter chamber. XRD, SEM, Nano Indenter and profiler were employed to investigate the influence of modulation periods and working pressures on structural and mechanical properties of the coatings. The low-angle XRD pattern and cross-sectional SEM indicated a well-defined composition modulation and layer structure of the multilayered coating. All multilayered coatings revealed higher hardness than the rule-of-mixtures value of monolithic ZrN and W₂N coatings at different working pressures. The maximum hardness was up to 34 GPa. The multilayers obtained mixed polycrystalline textures of ZrN(111), W₂N(111), W₂N(200) and W₂N(311). 0.8 Pa was an optimum working pressure for mechanical property enhancement.     

熔块法硒镉红釉的研制

论述了熔块法硒镉红釉的原理和工艺要点,给出了熔块组成及红釉实验配方。     

微波消解-ICP-MS测定蜂胶软胶囊中砷铅镉

采用微波消解法对蜂胶软胶囊样品进行处理,研究了微波消解和ICP-MS的测定条件,建立了微波消解-电感耦合等离子体质谱法测定蜂胶软胶囊中砷、铅,镉的方法。砷、铅、镉测定下限分别为0．08、0．02和0．02μg／g,RSD均小于3％,加标回收在99％～102％之间,方法用于实际样品分析。     

Controllable Synthesis of Single-Crystalline CdO and Cd(OH)<Subscript>2</Subscript>Nanowires by a Simple Hydrothermal Approach

Single-crystalline Cd(OH)₂ or CdO nanowires can be selectively synthesized at 150 °C by a simple hydrothermal method using aqueous Cd(NO₃)₂ as precursor. The method is biosafe, and compared to the conventional oil-water surfactant approach, more environmental-benign. As revealed by the XRD results, CdO or Cd(OH)₂ nanowires can be generated in high purity by varying the time of synthesis. The results of FESEM and HRTEM analysis show that the CdO nanowires are formed in bundles. Over the CdO-nanowire bundles, photoluminescence at ~517 nm attributable to near band-edge emission of CdO was recorded. Based on the experimental results, a possible growth mechanism of the products is proposed.     

锌镍合金镀层和镉镀层对30CrMnSiA结构钢疲劳性能影响的对比

采用电镀工艺在30CrMnSiA结构钢光滑与缺口试样上制备了锌镍合金镀层,采用升降法得到了锌镍合金镀层试样的疲劳极限,采用S-N曲线研究了锌镍合金镀层试样的疲劳性能,并与镉镀层试样的疲劳性能进行了对比。结果表明:不同循环周次下,锌镍合金镀层试样的疲劳极限与镉镀层试样的基本相同,不同应力水平下两种镀层试样的疲劳寿命也基本相当;从对基体材料疲劳性能的影响考虑,锌镍合金镀层可以替代镉镀层。     

Study on the Si penetration into Fe sheets using PVD method and its application in the fabrication of Fe-6.5 wt.% Si alloys

FeSi (12 wt.% Si) and Si were alternatively deposited on pure iron (Fe) substrates by direct current magnetron sputtering. Subsequent annealing in vacuum at 1150-1190 °C results in penetration of Si into the substrate. Cross-sectional microstructure and Si concentration were investigated by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The penetration mechanism is found to depend greatly on Si amount in the as-deposited films. When FeSi/Si/FeSi/Si/FeSi was deposited on the Fe substrate, the Si penetration is controlled by phase-boundary migration, while a diffusion-controlling penetration is observed in FeSi/Si/FeSi deposited samples. Fe-6.5 wt.% Si sheet with thickness of 0.35 mm is obtained through the deposition of FeSi/Si multilayer on a Fe-3 wt.% Si sheet together with subsequent annealing at 1180 °C for 2 h.