Ionic liquids as electrolytes

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors.     

轧机开卷卷取直流电机工作电流分析

对直流驱动开卷卷取机工作过程进行分析,按照励磁磁通饱和,和励磁弱磁两种工况分别考虑,计算出张力转矩和动态补偿转矩与料卷卷径的关系,从而求出在一道次轧制过程中的电机最大电流     

Food4Me study: Validity and reliability of Food Choice Questionnaire in 9 European countries

This analysis has been conducted to explore the validity and reliability of the Food Choice Questionnaire (FCQ) across 9 European countries. Variation in the factor structure and the perceived importance of food choice motives have been compared cross-nationally. Volunteers (N = 9381) were recruited from an existing panel of a social research agency to take part in the Food4Me survey in Germany, Greece, Ireland, Poland, Portugal, Spain, the Netherlands, the UK and Norway. The survey was administered on-line. Configural, metric and scalar invariance fell within acceptable limits and were consistent across the 9 countries. All reliability parameters were above acceptable levels. Factor analysis confirmed that all items loaded onto the same 9 factors established by Steptoe and Pollard (1995). There was highly significant agreement in the relative importance of food choice factors between countries. Price was ranked as most important food choice factor in five countries (Spain, Greece, Ireland, Portugal and the Netherlands), sensory appeal was ranked first for three countries (Norway, Germany and the UK) while natural content was ranked as the most important factor in Poland. Familiarity and ethical concern were consistently ranked as least important in all countries. These data suggest that the FCQ is a suitable tool for exploring food choice motives across different European populations. Differences in relative importance of factors within countries may need to be taken into account in dietary health intervention and food product development.     

Effect of alloying element on microstructure,mechanical property,and oxidation resistance of Zr─Me─C (Me═Si/Y) coatings

Accident-tolerant fuels (ATFs) are proposed to provide improved safety response to a loss of coolant accident (LOCA) scenario while maintaining good operational characteristics under normal conditions. In this work, Zr─Me─C (Me═Si or Y) was proposed as candidate coatings for ATF applications. The influence of Si and Y with varied concentration on microstructural evolution, mechanical property, and oxidation resistance of Zr─Me─C coatings were investigated. Based on combined results of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, it was found that Si or Y doped ZrC_0.55 coatings presented tunable composition and microstructure. Improved air oxidation and spallation resistance were achieved with the incorporation of Me atoms, attributing to the formation of SiO₂ and ZrSiO₄ and/or the stabilization of zirconia. Under a simulated LOCA condition, decreased weight gains of 13.6 at.% Si and 22.5 at.% Y coated Zry-4 alloys were achieved. nc-ZrSiC/nc-ZrSi (13.6 at.% Si) coating exhibited enhanced mechanical property and oxidation resistance in both high-temperature air and LOCA conditions, which could be regarded as potential candidate for the applications in ATFs.     

基于Linux的Beowulf集群的实现

中国科学院等离子体物理研究所是国内从事核聚变研究和托卡马克(Tokamak)实验的主要基地,由于实验研究的需要,有必要建立自己的大型并行计算机系统,进行托卡马克实验的数值模拟等研究课题。文章介绍了在普通PC机上利用Linux操作系统实现基于分布存储结构的Beowul集群系统的方法,同时也介绍了基于消息传递模型(Message Passing Interface,MPI)的并行程序设计方法。     

Synthesis, Characterization and Thermal Decomposition of Ln (Me2dtc)3(phen) (Ln=La, Pr, Nd, Sm)

Four solid complexes of Ln(Me2dtc)3(phen) (Ln=La, Pr, Nd, Sm) were synthesized in anhydrous ethanol by the reaction of lanthanide chloride low hydrate with the mixed ligand of sodium dimethyldithiocarbamate and 1, 10-phenanthroline·H2O (phen·H2O), and characterized by elemental analysis, IR spectroscopy, TG-DTG, and X-ray diffraction analysis. TG-DTG with X-ray powder diffraction showed that these compounds could decompose to lanthanide sulfides at relatively lower temperature, which indicated that the title complexes could be favorable precursors to prepare lanthanide sulfides.     

Studies on Me/Al-layered double hydroxides (Me = Ni and Co) as electrode materials for electrochemical capacitors

Me/Al-layered double hydroxides (Me=Ni and Co) prepared by the chemical co-precipitation method have been shown to be outstanding novel materials for electrochemical capacitors. The crystalline structure and the electrochemical properties of the electrodes have been studied by considering the effect of the mole ratio of nickel/cobalt. X-ray diffraction analysis shows that the materials belong to hexagonal system with layered structure. Cyclic voltammetric measurements indicate that Me/Al-layered double hydroxides with the Ni/Co mole ratio of 4:6 exhibit excellent capacitive properties within the potential range of 0.0-0.6 V versus Hg/HgO in 6 mol/L KOH electrolyte. Charge/discharge behaviors have been observed with the highest specific capacitance values of 960 F/g at the current density of 400 mA/g. Impedance studies show that the enhanced electrical properties and high frequency response are attributed to the presence of Co oxides.     

含油MC尼龙的摩擦磨损特性及应用

本文对黑龙江省尼龙厂研制的含油MC尼龙的摩擦磨损性能进行了测试,并与英国尼拉卡斯特有限公司生产的含油MC尼龙进行了比较。结果表明国产含油尼龙的性能基本达到或超过进口材料,比普通MC尼龙和固体润滑剂改性MC尼龙的耐磨减摩自润滑性有明显改善。最后对含油MC尼龙在造纸和橡胶工业上的成功应用做了介绍。     

以人为本,营造最佳人居环境--居住区绿化建设与管理浅析

居住区绿化是城市园林绿化系统的重要组成部分，是伴随现代化城市建设而产生的一种新型绿地，它最贴近生活、贴近居民，也是最能体现“以人为本”的现代理念。文章在指出存在问题的同时，提出了以人为本，营造最佳人居环境的多项措施，并指出需要处理好的几个关系。