A facile and convenient synthesis of disarmed glycosyl fluorides using in situ-generated iodine monofluoride (see Ref. , , , , , and )

A facile and convenient synthesis of disarmed glycosyl fluorides using in situ-generated iodine monofluoride is reported. The method is tolerant to most of the popularly used protecting groups and gives exclusively the α-anomeric product in very good yields.     

中国原子光谱发展近况概述

原子光谱技术作为现代分析检测技术中的一个重要组成部分,在分析领域中占据着举足轻重的地位,而其发展也反映了分析技术的不断改革与创新。综述了中国原子光谱技术近15年来(2000年—2014年)的研究与应用进展。内容涉及原子光谱的多个分支领域,包括原子发射光谱(atomic emission spectrometry,AES),原子吸收光谱(atomic absorption spectrometry,AAS),原子荧光光谱(atomic fluorescence spectrometry,AFS),X射线荧光光谱(X-ray fluorescence spectrometry, XRF)以及原子质谱(atomic mass spectrometry,AMS)五种原子光谱技术,重点关注各技术在检测方法上的创新及其在环境样品、生物样品、食品饮料以及地质材料等相关领域中的应用,并对原子光谱分析中利用到的各种联用技术进行了简要介绍。最后展望了今后我国原子光谱技术的发展方向。     

Organisation of carbon nanotubes and semiconductor nanowires using lateral alumina templates

Carbon nanotubes and semiconductor nanowires have been thoroughly studied for the future replacement of silicon-based complementary metal oxide semiconductor (CMOS) devices and circuits. However, the organisation of these nanomaterials in dense transistor arrays, where each device is capable of delivering drive currents comparable with those of their silicon counterparts is still a big challenge. Here, we present a novel approach to the organisation of carbon nanotubes and semiconductor nanowires, based on the use of porous lateral alumina templates obtained by the controlled anodic oxidation of aluminium thin films. We discuss the growth of nanomaterials inside the pores of such templates and show the feasibility of our approach. Our first results point to further work on controlling the synthesis of catalyst nanoparticles at the bottom of the pores, these particles being necessary to nucleate and sustain the growth of carbon nanotubes or semiconductor nanowires. To cite this article: D. Pribat et al., C. R. Physique 10 (2009).     

生物可降解及生物材料的电场纺丝及应用

电场纺丝是制备生物可降解及生物材料纳米纤维非织造布的简单工艺,由于纳米纤维具有较大的比表面积,具有多孔结构,使其在生物医学领域,如：组织工程、药物缓释及医用纱布等领域有潜在的应用前景。本文综述了生物降解材料及生物材料的电场纺丝及其应用。     

Quantitative Robust Uncertainty Principles and Optimally Sparse Decompositions

In this paper we develop a robust uncertainty principle for finite signals in which states that, for nearly all choices such that

Dispersion of Titanium（Ⅳ） Oxide Nanoparticles in Mixed Matrix Membrane Using Octaisobutyl Polyhedral Oligomeric Silsesquioxane for Enhanced CO2/CH4 Separation Performance

Titanium(IV) oxide (TiO2) nanoparticles have been incorporated into mixed matrix membranes (MMMs) to improve gas separation performance. However, TiO2 nanoparticles tend to agglomerate due to high surface energy and van der Waals forces. This leads to precipitation which causes the formation of non-homogeneous MMM morphology. In this study, the effect of octaisobutyl polyhedral oligomeric silsesquioxane (POSS) addition on TiO2/polysulfone MMM was investigated. The aims are to enhance gas separation performance whilst preventing agglomeration of TiO2 nanoparticles. The results demonstrated that inclusion of POSS as dispersant increases MMMs’ CO2/CH4 selectivity and permeance, possibly due to less void formation and more evenly distributed pore structure. For example, synergistic addition of 5 wt% TiO2 and 5 wt% POSS increased the CO2/CH4 selectivity up to 390% compared to MMM without POSS. This is supported by elemental mapping of titanium which revealed that POSS successfully dispersed TiO2 nanoparticles and prevented aggregation. TiO2-POSS/PSf MMMs also retained their favorable thermal stability.     

超声复合振动系统中的“局部共振”现象──20年来的应用和机理分析情况

本文作者及当时合作者在《应用声学》的创刊号中报道了超声振动系统中“局部共振”现象的发现及其一项应用。20年来,国内一些作者或者分别介绍了本现象在不同场合的应用,或者分别分析了这个现象的机理。值此《应用声学》庆祝创刊20周年之际,西文回顾了这些前期工作,提出了自己的一种关于机理的观点,并对“局部共振”现象的实用意义作了新的评价,希望能进一步促进这个现象的应用和对它的讨论。     

Copper sulfides and their composites for high-performance rechargeable batteries

Copper sulfides (Cu_xS) are widely used as the promising electrode materials for secondary batteries because of the rich abundance, low cost, excellent capacity (～337/560 mA h/g for Cu₂S/CuS) as well as favorable electrical conductivity (10^?3 S/cm). Moreover, nanostructure designing and compounding with other conductive materials can enhance the electrochemical performance of Cu_xS. In this review, the up-to-date progress in the synthesis method as well as the application for secondary batteries (lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, magnesium-ion batteries, and so on) of Cu_xS and their relevant composites have been discussed detailly. In the end, the challenges, feasible strategies, and application prospects for the Cu_xS are also summarized.