Single-crystal growth and anisotropic electrical properties of (La1?xCax)2CaCu2O6

Large single crystals of (La_1–x Ca _x )₂CaCu₂O₆ were synthesized by the travelling solvent floating zone (TSFZ) technique. The dimension of the grown boules was typically 4 mm×30 mm long with thec-axis perpendicular to the growth direction. After oxygen loading at 1080°C in 400 atm of O₂, they became superconductive with a sharp transition at around 50 K. The resistivity was metallic both along thec-axis and within theab-plane, with an anisotropy ratio of ²( _c/ _ab ) 50 which is almost independent of temperature. Details of the crystal growth, heat treatment procedures, and the results of electrical and magnetic property measurements are presented.     

La1-xNdxB6单晶的制备及热电子发射性能

以LaB_6和NdB_6粉末为原料,采用区域熔炼法成功制备了大尺寸、高质量的多元稀土六硼化物La_(1-x)Nd_xB_6(x=0.1~0.3)单晶,并测试了该系列单晶(100)晶面的热电子发射性能。本实验制备的单晶长度大于40mm,直径大于4mm。单晶衍射、劳埃照片、晶面摇摆曲线、单晶断口扫描等检测结果表明单晶质量较高,热发射测试结果表明在1 873K、4 000V下,单晶零场电流发射密度随着Nd含量增加从6.01A/cm~2降为4.83A/cm~2,有效逸出功从2.88eV增大到2.95eV。     

Production of perovskite-like La1−xCaxMnO3+δ ferromagnetic thin films by electrochemical reduction

Ferromagnetic and perovskite-like thin films (<1m) of La1–xCaxMnO3+ have been routinely prepared by heat treatment of an amorphous La–Ca–Mn precursor. The precursor was electrodeposited cathodically in the absence of oxygen and water onto polished silver substrates from a nonaqueous solution of the components' nitrates. Analysis by X-ray diffraction and SQUID magnetometry shows these materials exhibit the appropriate structural and magnetic phases indicative of colossal magnetoresistance.     

Paint Mesh Cutting

We present a novel progressive painting‐based mesh cut out tool, called Paint Mesh Cutting, for interactive mesh segmentation. Different from the previous user interfaces, the user only needs to draw a single stroke on the foreground region and then obtains the desired cutting part at an interactive rate. Moreover, the user progressively paints the region of interest using a brush and has the instant feedback on cutting results as he/she drags the mouse. This is achieved by efficient local graph‐cut based optimizations based on the Gaussian mixture models (GMM) on the shape diameter function (SDF) metric of the shape. We demonstrate a number of various examples to illustrate the flexibility and applicability of our system and present a user study that supports the advantages of our user interface.     

Fe掺杂LSCCF对中低温固体氧化物燃料电池ITSOFC短期输出性能的影响

柠檬酸盐法制备La0.7Sr0.15Ca0.15Co1-xFexO3-δ(x=0.2、0.4、0.6、0.8)阴极材料。该前驱体在900℃处理2h后,XRD证实已经形成完整的钙钛矿结构衍射峰。随Fe掺杂量增加,XRD谱图衍射峰的位置向小角度发生偏移,粉体的晶粒尺寸逐渐变大。SEM观察La0.7Sr0.15Ca0.15Co1-xFexO3-δ粉体其表面活性较高并出现了一定的团聚现象,颗粒尺寸约为5μm。以La0.7Sr0.15Ca0.15Co1-xFexO3-δ为阴极,在氢气/空气中研究了模压法制备的单电池性能,Fe掺杂量对开路电压的高低不起决定性作用,而最高功率密度随Fe掺杂量增加而降低,在650℃最高功率密度由x=0.2时的351.7mW/cm2降为x=0.8时的231.1mW/cm2。     

新型La2Mo2O9基氧离子导体的研究进展

自2000年Lacorre等人报道La2Mo2O9具有较高的氧离子电导率以来，La2Mo2O9基氧离子导体由于具有优异的性能而受到人们的关注．本文综述了新型氧离子导体La2Mo2O9的研究现状．重点介绍了纯La2Mo2O9及其掺杂体系的结构与相变、氧离子电导率、氧空位扩散机理、化学稳定性和热膨胀系数等性能．已有的研究结果表明，基于La2Mo2O9的氧离子导体可望在固体氧化物燃料电池、氧传感器、透氧膜等方面得到应用．     

La2O3对钼烧结坯力学性能的影响

本文研究了La2O3对钼烧结坯力学性能的影响。将纯钼及不同La2O3含量的ODS钼合金在1500℃和2050℃真空退火后，测试其力学性能。结果表明，添加La2O3后，无论是轧制状态还是高温退火后，材料的抗拉强度均显著高于相同加工状态的纯钼。La2O3强化钼合金的再结晶温度显著提高，因此具有优异的高温性能，从而改善了材料从高温加热回复至室温的低温脆性。     

掺La对钼粉还原过程及粉体颗粒的影响

通过各种检测手段对不同La2O3含量及不同掺杂方式中，钼粉还原过程及粉体进行了系统的研究。结果表明：掺杂方式对La分布均匀性有显著影响，以二氧化钼为掺杂母体的La分布均匀性较以纯钼粉为母体时的均匀性高；La2O3在还原过程中起到细化粉末的作用。     

降低碳铵沉淀法生产氧化镧中氯离子含量的研究

为降低碳铵沉淀法生产氧化镧中氯离子含量，在不变换体系的情况下，通过改进沉淀工艺，选择多种洗涤剂进行比较及筛选试验，有效地解决了氧化镧中氯离子含量高的问题，将其应用于镧热还原一炉渣（即镧渣）回收氧化镧产品的生产实践中．获得了理想的效果。     

Effects of La(NO_3)_3 Treatment on Photocattalytic Activity of TiO_2 Films Prepared by Micro-Arc Oxidation

Effects of La(NO_3)_3 Treatment on Photocattalytic Activity of TiO_2 Films Prepared by Micro-Arc Oxidation