聚丙烯催化合金结构表征

用IR、DSC、NMR分析了聚丙烯催化合金中乙丙共聚物的微结构 ,发现在一定条件下合成的乙丙共聚物主要由两部分组成 :无规乙丙共聚物和各种不同序列长度的乙丙嵌段物组成 .加上丙烯均聚物 ,聚丙烯催化合金是一种具有多分散性结构的混合物 .这种特殊的结构是聚丙烯催化合金具有高抗冲性的主要原因     

超声马达摩擦学及其摩擦材料研究进展

超声马达是一种新型原动机，与普通电磁马达不同，这是一种摩擦驱动马达．为了促进超声马达的发展，对其研究中关于定子与转子界面接触驱动特性和摩擦磨损特性，超声波振动对定子和转子接触界面摩擦学特性的影响，转子摩擦材料的选择及其寿命预测等，从摩擦学角度对国内外的研究进展进行了综合归纳与评述，并且针对超声马达摩擦驱动的特点，提出了当前值得重视的一些研究内容．     

奇异二阶微分系统正周期解的存在性

通过研究一类带周期边界条件的二阶线性算子的性质,运用Schauder不动点定理在较弱的条件下获得奇异二阶系统（1．1）正周期解的存在性,所得结论推广和改进了已有工作的相关结果．     

Three radially symmetric k-admissible solutions for k-Hessian equation

We show the existence of three radially symmetric k-admissible solutions for k-Hessian equation with 0-Dirichlet boundary condition under suitable conditions on the nonlinearity. Proofs are mainly based on the bifurcation technique.     

基于尺寸效应的FG-SMA微梁非线性自由振动特性研究

形状记忆合金具有相变温度低、输出应力高、能耗小、驱动电压低、可恢复应变大、生物相容性好等特性.随着形状记忆合金制备技术的进一步发展,有学者提出将功能梯度形状记忆合金材料用于微机电系统等智能微结构,将使其具有更优良的特性.因此开展机电多场耦合功能梯度形状记忆合金微结构的非线性自由振动特性研究具有重要研究价值.论文基于冯卡门几何非线性理论,综合考虑静电力和分子间作用力的影响,考虑尺寸效应,基于修正偶应力理论,建立两端固定的功能梯度形状记忆合金微梁模型,对功能梯度形状记忆合金微梁相变前后的机电耦合非线性自由振动问题进行深入研究,分析了尺寸效应参数、几何结构参数和相变参数等对功能梯度形状记忆合金微梁自由振动特性的影响.     

Preparation and quantification of the total phenolic products in Citrus fruit using solid‐phase extraction coupled with high‐performance liquid chromatography with diode array and UV detection

Citrus fruit is an important health‐promoting food that is rich in dietary phenolic metabolites. Traditional Chinese medicines, such as Zhishi and Zhiqiao, come from young and immature fruits of Citrus cultivars. The preparation of diversified bioactive phenolic products and establishment of the corresponding quality control methodology are challenging and necessary. In the current study, four types of solid‐phase extraction sorbents for the enrichment and clean‐up of the phenolic matrix were evaluated. A solid‐phase extraction column coated with Strata‐X was finally used in the procedure. Twenty phenolic compounds were selected to evaluate the extraction performances of the sorbents using high‐performance liquid chromatography analysis. Under the optimized conditions, good linearities were obtained with R² more than 0.9996 for all analytes with LODs of 0.04–1.012 μg/g. Intra‐ and interday relative standard deviation values were less than 3%, and the recovery was equal to or higher than 90.02%. Compared to non‐solid‐phase extraction process, the content of total phenolic products was elevated 35.55–68.48% with solid‐phase extraction. Finally, the developed and validated method was successfully applied to the discrimination of Zhishi samples from different species as well as Zhishi and Zhiqiao samples in different development stages.     

Nucleation and growth of Ge nanoclusters on the Si(111)‐(7 × 7) surface studied by scanning tunneling microscopy

Nucleation and growth of two‐dimensional Ge nanoclusters on the Si(111)‐(7 × 7) surface at elevated substrate temperatures have been studied using scanning tunneling microscopy. The uniformity of the Ge nanoclusters is improved with the increase of substrate temperature, and ordered Ge nanoclusters are formed on the faulted and unfaulted halves of (7 × 7) unit cell at substrate temperature of 200 °C. It is proposed that the Ge nanoclusters consist of six Ge atoms with three on top of the center adatoms and others on the rest atoms within one half of a unit cell. Copyright © 2014 John Wiley & Sons, Ltd.     

Spatio-Temporally Reporting Dose-Dependent Chemotherapy via Uniting Dual-Modal MRI/NIR Imaging

Unpredictable in vivo therapeutic feedback of hydroxyl radical (^.OH) efficiency is the major bottleneck of chemodynamic therapy. Herein, we describe novel Fenton-based nanotheranostics NQ-Cy@Fe&GOD for spatio-temporally reporting intratumor ^.OH-mediated treatment, which innovatively unites dual-channel near-infrared (NIR) fluorescence and magnetic resonance imaging (MRI) signals. Specifically, MRI signal traces the dose distribution of Fenton-based iron oxide nanoparticles (IONPs) with high-spatial resolution, meanwhile timely fluorescence signal quantifies ^.OH-mediated therapeutic response with high spatio-temporal resolution. NQ-Cy@Fe&GOD can successfully monitor the intracellular release of IONPs and ^.OH-induced NQO1 enzyme in living cells and tumor-bearing mice, which makes a breakthrough in conquering the inherent unpredictable obstacles on spatio-temporally reporting chemodynamic therapy, so as to manipulate dose-dependent therapeutic process.     

Ultrathin Au-Ag bimetallic nanowires with Coulomb blockade effects

Ultrathin Au/Ag bimetallic nanowires with remarkable Coulomb blockade effects were synthesized using octadecylamine as both a solvent and a surfactant. It is believed that the growth mechanism of the Au/Ag bimetallic ultrathin nanowires includes the noble-metal-induced reduction, the oriented attachment and the wire-wire fusion.     

Photocaged prodrug under NIR light-triggering with dual-channel fluorescence: <Emphasis Type="Italic">in vivo</Emphasis> real-time tracking for precise drug delivery

Light-triggered drug delivery system is an effective strategy for precise diagnosis and therapy in cancer treatment. However, it suffers from difficultly balancing the dosimetry of drug with light dose and a lack of in vivo models for validating their clinical benefits. Here we report an unprecedented near-infrared (NIR) light photocaged cyanine-based prodrug Cy-CPT-Biotin with dual-channel fluorescence mode, enabling NIR light to precisely regulate where, when and how the intact and active prodrugs are delivered. The synergy of photochemical reaction and modulation in π-conjugated polyene backbone of cyanine can fully perform distinct dual-channel fluorescence changes in a NIR light-mediated manner. The prodrug has striking characteristics of excellent tumor-targeting ability, real-time monitoring of the in vivo behaviors by dual-channel mode and NIR-light triggering, especially for achieving fine regulation and on-demand drug release in the precise dosimetry of drug with light dose in living animals. This optical orthogonality strategy that conjuncts with NIR light-triggered and dual-channel fluorescence in vivo imaging provides a powerful tool for in vivo real-time tracking and finely tuning the prodrug release for precise drug delivery.