也谈运输问题"悖论"产生的条件

本文分析、归纳了关于运输问题“悖论”的若干讨论；提出产生悖论的一个充要条件；由于该充要条件对于退化情形也适用，从而改进了以往的结果。     

Y掺杂Ba0.90 Sr0.08 Ca0.02 TiO3固溶体纳米晶粒尺寸对其晶体结构的影响

随着电子陶瓷材料向精细、微型、多功能化的方向发展，陶瓷用的粉体晶粒尺寸对物性影响的研究显得越来越重要。钡系钙钛矿结构铁电材料是应用极为广泛的电子陶瓷材料，其铁电性与晶粒尺寸密切相关，尤其是达到纳米级时，可使材料性质发生奇异变化。迄今人们仅对纯ＢａＴｉＯ３超微细粒子的晶粒尺寸对铁电相变的影响进行了研究［１～３］，对稀土钇掺杂Ｂａ（１－ｘ－ｙ）ＳｒｘＣａｙＴｉＯ３固溶体纳米晶的相关研究报道尚少，而铁电尺寸效应对这类电子功能材料的研究、开发起着关键作用。因此，开展这方面的研究具有重要的学术价值和实际意…     

竞争紫外-可见光谱法研究β-环糊精与链状饱和一元醇的包合作用

以酚酞作为光谱探针,采用竞争紫外-可见光谱法研究了β-环糊精与链状饱和一元醇的包合作用。通过测定包合物的稳定常数和热力学参数发现,β-环糊精对饱和一元醇的包合作用随醇的碳原子数的增加而增加,且对支链醇的包合稳定性要高于相同碳原子数的直链醇。β-环糊精与链状饱和一元醇分子间的疏水相互作用和空间匹配效应可能是影响包合作用的关键因素。     

三联吡啶钌电致化学发光法测定苯磺酸顺阿曲库铵

基于硼砂溶液中Ru(bpy)32+的弱电化学发光信号可被苯磺酸顺阿曲库铵增敏,建立了测定苯磺酸顺阿曲库铵的电化学发光(ECL)新方法。在最佳条件下,苯磺酸顺阿曲库铵浓度在2.0×10-6～3.2×10-5mol/L范围内与其相对发光强度呈线性关系(r2=0.9999),检出限为4.0×10-8mol/L(S/N=3)。重复测定高、低浓度(2.4×10-5mol/L,3.2×10-6mol/L)的苯磺酸顺阿曲库铵溶液9次,其RSD均为3.2%,方法具有较好的重现性。方法已用于注射用苯磺酸顺阿曲库铵的测定。     

The Preparation and Characterization of La Doped TiO2 Nanotubes and Their Photocatalytic Activity

La-doped TiO₂ nanotubes (La/TiO₂ NTs) were prepared by the combination of sol-gel process with hydrothermal treatment. The prepared samples were characterized by using transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectra, and ultraviolet-visible spectra. The photocatalytic performance of La/TiO₂ NTs was studied by testing the degradation rate of methyl orange under ultraviolet (UV) irradiation. The results indicated La/TiO₂ NTs calcined at 300°C consisted of anatase as the unique phase. The absorption spectra of the La/TiO₂ NTs showed a stronger absorption in the UV range and a slight red shift in the band gap transition than that of pure TiO₂ nanotubes. The photocatalytic performance of TiO₂ NTs could be improved by the doping of lanthanum ions, which is ascribed to several beneficial effects the formation of Ti-O-La bond and charge imbalance, existing of oxygen defects and Ti³⁺ species, stronger absorption in the UV range and a slight red shift in the band gap transition, as well as higher equilibrium dark adsorption of methyl orange. 0.75 wt% La/TiO₂ NTs had the best catalytic activity.     

INTERFACE FORMATION OF Ge/ZnSe(100) AND Ge/ZnS(111) HETEROJUNCTIONS STUDIED BY SYNCHROTRON RADIATION PHOTOEMISSION

The microscopic evolution of interface formation between Ge and Ⅱ-Ⅵ compounds such as ZnSe and ZnS single crystals has been studied by synchrotron radiation photoemission spectroscopy and low energy electron diffraction. Core level intensity measurements from the substrate as well as from the overlayer show a nearly ideal two-dimensional growth mode for the deposition of Ge on ZnSe(100) surface. How-ever, there is a certain deviation from the ideal two-dimensional mode in the case of Ge/ZnS(111) due to the diffusion of substrate atoms into Ge overlayer. Surface semi-tire core level spectra indicate that the reaction of Ge with S atoms at Ge/ZnS(111) interfaces is much stronger than that of Ge with Se atoms at Ge/ZnSe(100) interfaces.     

遗传算法在冲击隔振中的应用研究

借助泰勒级数给出了钢丝绳隔振器的一阶近似非线性数学模型, 选用遗传算法对系统固有频 率进行二进制编码; 然后建立了相应的冲击仿真模型, 并对冲击载荷作用下装有钢丝绳隔振 器的移动硬盘进行仿真实验. 理论分析与仿真结果表明, 采用遗传算法的仿真模型能够适应 脉冲宽度的多变性, 克服隔振效果与最大允许变形之间的矛盾, 良好地反演出钢丝绳隔振系 统的固有频率.     

大粘度复合纳米材料面投影微立体光刻系统的分辨率研究

 基于数字微反射镜的动态掩膜面投影微立体光刻技术是一种基于快速原型制造思想的新型微细结构加工手段,其系统中常用树脂槽和涂覆装置使得其无法适用于粘度大的固化材料。为实现粘度大的复合纳米材料的固化制造,构建了新型的基于数字微反射镜技术的动态掩膜微立体光刻系统,该系统的加工横向分辨率由系统的光学分辨率与树脂特性共同决定。当单层树脂固化厚度超过临界值时,系统的横向分辨率将降低。根据实验中测量光学系统的分辨率以及树脂的工作曲线,得到本系统的最高横向分辨率可以达到14 μm。     

烟酸诺氟沙星和乳酸诺氟沙星的荧光特性及应用

研究了烟酸诺氟沙星和乳酸诺氟沙星在不同介质中的荧光特性。采用荧光分光光度法测定了烟酸诺氟沙星和乳酸诺氟沙星的含量。烟酸诺氟沙星和乳酸诺氟沙星分别在0.025—2.5μg/mL和0.01—2μg/mL范围内,其荧光强度与浓度线性关系良好。