稀土材料新进展

叙述了稀土材料的新种类以及应用前景，并对国内稀土工业的现状及其存在的问题、国外稀土市场概况进行了综述，同时，展望了我国稀土材料的发展方向。     

Critical State of Granular Materials Based on the Sliding-Rolling Theory

By representing the assembly by a simplified column model, a constitutive theory was recently developed for a two-dimensional assembly of rods. This theory, referred to as the sliding-rolling theory, is extended in this paper to represent the triaxial stress-strain behavior of granular materials. The sliding-rolling theory provides a dilatancy rule and an expression for the slope of the line of zero dilatancy in the stress space. These rules are then combined with triaxial observations to provide a microstructural interpretation of the critical state of granular materials. According to the theory, the slope of the critical state line in the stress space depends on the interparticle friction angle and the degree of contact normal anisotropy. To verify the basic ideas of the sliding-rolling theory, numerical experiments are conducted using the discrete-element method on three-dimensional assemblies of spheres.     

液态金属实验回路(LMEL)的总体设计和运行

液态金属实验回路（ＬＭＥＬ）是国内唯一用于聚变堆磁流体动力学（ＭＨＤ）效应和材料相容性研究的大型实验装置。与国外同类先进的装置相比，回路流程和运行方式均有重大改进，使其更先进、安全并具有多功能。回路运行分为两个阶段：第一阶段以钠－钾低共熔合金（２２Ｎａ７８Ｋ）为工质，研究ＭＨＤ效应，ＬＭＥＬ的最大哈特曼（Ｈａｒｔｍａｎｎ）数Ｍ和相互作用参数Ｎ分别为０．７５×１０４和２．５×１０４；第二阶段以液态锂为工质，研究结构材料与锂的相容性，最高温度和流速分别为５２０℃和１．３８ｍ／ｓ。     

二维三氧化钨纳米结构的合成及其在光电探测器中的应用

三氧化钨（WO₃）是制造晶体管和光电探测器的理想材料,虽然在WO₃纳米结构的生长方面已经完成了一些工作,但是制造足够长的理想型纳米线仍然是一个挑战。在众多的合成方法中,作者选择了化学气相沉积（CVD）方法合成WO₃纳米线,并对其在光电传感器中的应用进行了研究。影响WO₃纳米线成品率的主要因素是前体材料温度、基片位置、载气流速和生长持续时间。在合适的生长条件下生长的纳米线长度最长约为100 μm。这些WO₃纳米线可用来制造高性能的光电探测器,WO₃光电探测器具有灵敏度高、响应速度快、模块微型化等优良的器件性能,表明二维WO₃纳米线在光电探测器的制造中具有很大的优势。      

Preparation and structure of fluorinated/non-fluorinated polyacrylate gradient emulsion blend film

The emulsion blend method, which is environmentally friendly and energy saving, was used to prepare a compositional gradient film of fluorinated/non-fluorinated polyacrylate in this paper. The size and glass-transition temperature (T_g) of the emulsion particles were designed to enhance the driving force of their selective congregation and promote the formation of gradient structure. The structures and surface properties of the obtained films were characterized. The results showed that when the fluorinated components have much smaller particle size and higher T_g than those of fluorine-free polyacrylate components, the gradient structures formed in the direction across the film thickness of the films. The concentration of the fluorinated component increased gradually from film-glass interface to film-air interface in the blend film, making the surface free energies of the two sides of the gradient film distinctively different.     

Metal‐containing Polymers via Electropolymerization

Electropolymerization represents a suitable and well‐established approach for the assembly of polymer structures, in particular with regard to the formation of thin, insoluble films. Utilization of monomers that are functionalized with metal complex units allows the combination of structural and functional benefits of polymers and metal moieties. Since a broad range of both electropolymerizable monomers and metal complexes are available, various structures and, thus, applications are possible. Recent developments in the field of synthesis and potential applications of metal‐functionalized polymers obtained via electropolymerization are presented, highlighting the significant advances in this field of research.     

Correlation between structural and optical properties of 30 nm and 60 nm lead sulfide nanowires

PbS nanowires with 30 nm and 60 nm diameter fabricated under the same condition of electrochemical deposition with sulfuric and oxalic anodic alumina membranes (AAM), respectively, have been successfully prepared in order to study their optical properties in relation to their size. Scanning electron microscopy indicates that the 60 nm PbS nanowire arrays have the same shape with the 30 nm. X-ray diffraction result shows that 60 nm PbS nanowires are crystalline and have a highly (200) preferential orientation like 30 nm ones. UV spectrum considers the nanowire size decrease as the absorption peak shifts to the blue. The quantum confinement effects compared between 30 nm and 60 nm PbS nanowire arrays were observed by the measurements of ultraviolet-visible absorption spectroscopy (UV-vis).     

纳米WO3材料的制备、应用及研究趋势

结合近年来国内外相关文献，综述了纳米WO3材料的研究现状与进展，重点概述了超细WO3粉体和纳米WO3薄膜的各种制备方法及各自优缺点，并介绍了纳米WO3薄膜的稀有金属掺杂研究等；分析了纳米WO3材料的研究意义，介绍了纳米WO3材料在变色及催化等方面的应用。最后分析了纳米WO3材料应用的发展趋势。     

Hydrogen plasma treatment of very thin p-type nanocrystalline Si films grown by RF-PECVD in the presence of B(CH3)3

Abstract

We have characterized the structure and electrical properties of p-type nanocrystalline silicon films prepared by radio-frequency plasma-enhanced chemical vapor deposition and explored optimization methods of such layers for potential applications in thin-film solar cells. Particular attention was paid to the characterization of very thin (～20 nm) films. The cross-sectional morphology of the layers was studied by fitting the ellipsometry spectra using a multilayer model. The results suggest that the crystallization process in a high-pressure growth regime is mostly realized through a subsurface mechanism in the absence of the incubation layer at the substrate-film interface. Hydrogen plasma treatment of a 22-nm-thick film improved its electrical properties (conductivity increased more than ten times) owing to hydrogen insertion and Si structure rearrangements throughout the entire thickness of the film.     

脲醛树脂基高分子材料改性研究

本文简要介绍了脲醛树脂基高分子材料的基本生产工艺流程,探索玻璃纤维、纳米蒙脱土、丁腈橡胶粉以及玉米淀粉种类和用量对脲醛树脂基高分子材料耐电击穿性能的影响。实验结果表明,选用玻璃纤维作为增强剂对脲醛树脂基高分子材料的耐电击穿强度影响最为明显,纳米蒙脱土次之,玉米淀粉的加入对脲醛树脂基高分子材料的耐电击穿强度影响不明显,而丁腈橡胶的加入对脲醛树脂基高分子材料的耐电击穿强度有明显的下降趋势,改性后的脲醛树脂基高分子材料的耐电击穿强度能超过17KV/mm,最佳耐压时间在100s以上。