On a Discrete Fractional Boundary Value Problem with Nonlocal Fractional Boundary Conditions

In this paper, we investigate the nonlinear fractional difference equation with nonlocal fractional boundary conditions. We derive the Green＇s function for this problem and show that it satisfies certain properties. Some existence results are obtained by means of nonlinear alternative of Leray-Schauder type theorem and Krasnosel-skii＇s fixed point theorem.     

Molecule motion at polymer brush interfaces from single‐molecule experimental perspectives

Polymer brushes have been widely used as functional surface coatings for broad applications including antifouling, energy storage, and lubrications. Understanding the molecule dynamics at polymer brush interfaces is important in unraveling the structure–property relationships in these materials and establishing a new materials design paradigm of novel functional polymer thin films with efficient interfacial transport. By applying modern fluorescence‐based single‐molecule spectroscopic and microscopic techniques, molecule dynamics at varied polymer brush interfaces have been experimentally investigated in recent years. New insights are given to the understandings of some unique and unusual materials properties of polymer brush thin films. This review summarizes some recent studies of molecular diffusion at polymer brush interfaces, highlights some new understandings of the interfacial properties of polymer brushes, and discusses future research opportunities in this field. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014 , 52, 85–103     

Preparation and Characterization of Chitosan-Blended Multiwalled Carbon Nanotubes

Composites comprised of chitosan (CS) and multiwalled carbon nanotubes (MWCNTs) were fabricated by milling and ultrasonication dispersion methods. Scanning electron microscopy images showed homogeneous dispersion of MWCNTs throughout the CS matrix for samples prepared by either ultrasonication or milling methods. Further, the crystallinity of the CS component was found to decrease with the addition of MWCNTs, although the decomposition temperature and the storage modulus (E′) of the samples were improved. The decomposition temperature for the composite prepared by milling was 7°C higher than that by the ultrasonication. Meanwhile, the E′ decreased relatively slowly with temperature in the dynamic mechanical analysis measurements. In addition, IR analysis implied an interaction between CS and MWCNTs, which likely originated from hydrogen bonds between the amino, hydroxyl, and carboxyl groups of the two components. Compared with the ultrasonication, milling was more effective to promote the formation of the hydrogen bonds between CS and the MWCNTs and thus enhance the thermal stability of CS.     

两种测定果汁中钾磷含量方法的比较与分析

采用微波消解-等离子体发射光谱法同时测定果汁中K、P含量,优化了实验所需的各种条件。与国家标准方法湿法消解-分光光度法的测定结果作了实验比较,结果表明本实验方法更简单、高效,节省了样品的前处理时间,减小了最终结果的误差。该法灵敏度高、线性范围宽、加标回收率高,结果令人满意。     

HL-2M 真空室保温层设计及安装

基于 HL-2M 真空室烘烤保温要求，通过有限元分析和原型件实验确定采用陶瓷纤维与纳米级微孔材 料组合作为 HL-2M 真空室保温材料。在 30℃时，保温层的导热系数小于 0.027W⋅m⁻¹·℃⁻¹；300℃时，导热系数 小于 0.038W⋅m⁻¹·℃⁻¹。在保温层厚度 25mm、热面温度 300℃且达到稳态时，冷面可控制在 85℃以下，线圈侧的 温度低于 60℃，整体热损失小于 12kW，满足 HL-2M 真空室烘烤需求。      

新型川芎嗪衍生物的合成

以川芎嗪为原料，经氧化、Boekelheide重排、水解和氧化反应合成了中间体3,5,6-三甲基吡嗪-2-甲醛（4）; 4与取代N-4-哌啶酮发生缩合反应合成了9个新型的川芎嗪衍生物，其结构经¹H NMR, ¹³C NMR和MS（ESI）表征。     

Natural convection heat transfer at reduced pressures

This paper experimentally studies the natural convection heat transfer characteristics on horizontal and vertical plates at pressures lower than atmospheric value. Eight different pressures ranging from 10Pa to 101.325kPa, and three heating loads were used in the experiments. It is found that natural convection heat transfer characteristics at reduced pressures are independent of the plate arrangements and present different behaviors in two pressure ranges, 10Pa < p < 1000Pa and p > 1000Pa. The experimental heat transfer results are correlated into a non-dimensional equation to help the thermal design of stratosphere aircrafts and airborne equipment.     

Upgrading Pectin Production from Apple Pomace by Acetic Acid Extraction

Applied Biochemistry and Biotechnology - Pectin, as one of the most widely used functional polysaccharide, can be abundantly extracted from apple pomace which is the main by-product of apple juice...