Thermodynamic assessments of the Cu–Th and Mo–Th systems

The thermodynamic assessments of the Cu–Th and Mo–Th binary systems were carried out by using Calculation of Phase Diagrams (CALPHAD) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, and fcc phases are described by the subregular solution model with the Redlich–Kister equation and those of the four intermetallic compounds Cu₆Th, Cu_3.6Th, Cu₂Th and CuTh₂ in the Cu–Th binary system were described by the sublattice model. A set of self-consistent thermodynamic parameters are obtained, and the calculated phase diagrams and thermodynamic properties are presented and compared with the experimental data from literatures. The calculated thermodynamic properties as well as phase diagrams are in good agreement with the experimental data.     

中子活化分析研究长期摄入氯化镧对大鼠脑中部分常量和微量元素含量的影响

利用中子活化分析技术,初步研究了长期从饮水中摄入不同剂量的稀土元素镧对大鼠脑中12种常量和微量元素含量的影响。结果发现,镧的剂量越高,实验大鼠脑组织中含量发生变化的元素种类越多。1000mg/L组大鼠脑组织中有5种元素的含量与对照组相比发生了明显改变,而且这些元素都与脑功能密切相关。因此,镧的摄入可能会对脑的功能产生不利影响。     

Effect of components on the microstructures and properties of rare-earth zirconate ceramics prepared by ultrafast high-throughput sintering

Rare-earth zirconate ceramics are conventionally sintered at high temperatures for long durations to achieve a full density. Herein, we synthesized and densified five lanthanide-group rare-earth zirconates (Ln₂Zr₂O₇, Ln = La, Nd, Sm, Eu, Gd) containing different numbers of Ln cations in a high-throughput mode using a novel ultrafast high-temperature sintering technique within a cycle of 5 min, and investigated the effects of components on the structure and properties of the resultant ceramics. Under the high-throughput mode, the same sintering conditions make the analysis and comparison of the results more reasonable. The average grain size decreased while hardness and Young’s modulus increased with an increase in the number of the Ln components in the zirconate ceramics. The mechanisms were ascribed to the sluggish diffusion and lattice distortion effect caused by the increase in entropy.     

中国NdFeB磁体产业的10周年

中国NdFeB磁体的研制始于1983年,此后全国如此众多的大学和研究所均介入NdFeB磁体的研究与开发。与此同时,NdFeB磁体的生产也迅速增长。今天中国NdFeB磁体的产量仅次于日本,位居世界第二。本文评述中国NdFeB磁体产业的发展现状和前景,以作为我国NdFeB磁体产业10年历程的纪念。     

Synthesis and optical properties of Yb0.6Y1.4O3 transparent ceramics

Transparent yttrium oxide ceramics doped with 30 at.% ytterbium were successfully produced by a combination of pre-sintering and hot isostatic pressing. The influence on the final transparency of different densification states and porosity configurations obtained by varying pre-sintering conditions were investigated by optical and electron microscopy. Our results show that densification prior to the final stage of sintering is necessary to limit final porosity. Samples showing open porosity were found to lead to pore entrapment because of the diffusion of argon inside the glass capsule during hot isostatic pressing. Transmittance measurements showed that the valence charge of the ytterbium ions was 3+ at the end of the process, indicating no effect of reduction when pre-sintering in vacuum was employed.     

稀土催化反应器净化柴油机排气微粒的实验研究

癌旁粘膜无论在形态和组织化学上都常与正常粘膜有差异。曾有人认为癌旁粘膜处于癌前病变状态。我们用聚合酶链式反应－－限制性片段长度多态性（ＰＣＲ－ＲＦＬＰ）分析方法检测了１３例结直肠癌及其相邻粘膜中ｋｉ－ｒａｓ基因的空变情况。结果发现癌组织和癌旁粘膜都有ｋｉ－ｒａｓ突变２例，仅癌组织有突变的２例，仅癌旁粘膜有突变有１例。该结果说明部分癌旁粘膜已经发生了ｋｉ－ｒａｓ基因的突变，并进一步证实ｋｉ－ｒａｓ     

稀土有机化合物做酸酐/环氧树脂体系潜伏性促进剂的研究

本文应用DSC、旋转粘度计和凝胶化时间测定仪等分析技术对一种稀土有机金属化合物／酸酐／环氧树脂体系的潜伏性、固化反应动力学和固化物的性能进行了研究，且与叔胺／酸酐／环氧树脂体系进行了对比。     

稀土永磁材料微观结构与技术磁性关系的现状和研究设想

本文阐明了永磁材料的微观结构和技术磁性的内涵和意义。根据反磁化过程中反向畴壁形成和运动的具体特点,综述了稀土永磁材料微观结构和技术磁性关系的研究现状,提出了引入数值计算方法进一步研究其结构-性能关系的某些设想。     

Effects of europium concentration on luminescent and scintillation performance of Cs0.2Rb0.8Ca1-xEuxBr3(0≤x≤0.08)crystals

A series of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃(0≤x≤0.08)crystals doped with different concentrations of Eu²⁺were grown using the Bridgman-Stockbarger method.The work describes the influence of Eu²⁺concentration on the luminescent and kinetic properties of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃ crystals,as well as on their scintillation performance.The maximum in the radioluminescence spectra of these crystals shifts from 439 to446 nm with increasing europium concentration.The scintillation decay times of Cs_0.2Rb_0.8Ca_1-xEu_xBr₃ lengthen with the Eu²⁺content.The best light output of 33600photons/MeV is obtained for Cs_0.2Rb_0.8Ca_0.93Eu_0.07Br₃,and the best energy resolution of 6.9%is found for Cs_0.2Rb_0.8Ca_0.94Eu_0.06Br₃.