In situ impedance study of the Y-Ni thin film under electrochemical hydrogenation

A thin film of yttrium Y (150 nm) protected by a 6 nm coating of nickel Ni on a glass substrate was completely hydrogenated in a 1 M NaOH electrolyte at a constant negative current until the transparent Y tri-hydride phase was achieved and hydrogen gas evolution from the electrode began. A series of impedance measurements were performed in situ during the electrochemical experiment to study the properties of the system as dependent on hydrogenation degree and time of relaxation. The equivalent electrical circuit (EEC) simulations were performed with a Randles-like scheme R₀[R₁CPE₁], where R₀ is the thin film electrode resistance, R₁ the charge transfer resistance and CPE₁ is the capacitive constant phase element. The behavior of all the components of the EEC undergoes a clear transition when the hydrogenation degree of the electrode is approximated to its maximum value (H to Y ratio 2.7) and electrochemical process changes from hydrogen uptake to hydrogen evolution.     

The hydrogenation of toluene over nickel loaded Y zeolites

The catalytic activities of a range of hydrogen reduced nickel Y zeolites for the hydrogenation of toluene were measured and correlated with the following catalytic parameters: reaction temperature; reaction time; coke deposition. The role of the alkali metal co-cation (Li⁺, Na⁺, K⁺, Rb⁺ or Cs⁺) in influencing the overall hydrogenation activity of the supported nickel metal was probed. The effect of poisoning the surface Bronsted acidity by the adsorption of ammonia is discussed. For comparative purposes, data on the hydrogenation of benzene over the same catalysts are included.     

Gender,culture and determinants of behavioural intents to adopt mobile commerce among the Y Generation in transition economies: evidence from Kazakhstan

This study investigates perceived risk and trust in relationship to the Diffusion of Innovation Theory [Rogers, E.M., 1962. Diffusion of innovations. Glencoe, IL: The Free Press; 1983. Diffusion of innovations. 3rd ed. New York: The Free Press] from a cultural perspective to understand the determinants of behavioural intent to adopt mobile commerce among the Y Generation in Kazakhstan. Surveys from 345 university-level students and subsequent structural equation modelling revealed perceived risk, trustworthiness and Rogers’ five innovation characteristics are important determinants. Perceived risk and trustworthiness are important determinants because of the high uncertainty avoidance characteristics of the Kazakh society. This study advances theory regarding culture- and generation-based characteristics to transition economies by verifying theoretical proposition regarding the behavioural intent towards mobile commerce adoption, resulting in a greater understanding of mobile commerce adoption among the Y Generation in transition economies. Marketing implications are discussed.     

DNA recognition by a {beta}-sheet

DNA recognition by a ß-sheet is discussed in the lightof crystal structures of the MetJ and Arc repressors. The DNAbinding geometry of a ß-sheet can be understood interms of (i) close fitting of the two surfaces and (ii) matchingof residue and base positions. A ß-sheet is not entirelyflat but has a curvature. A ß-sheet of the Met-Arcfamily faces the DNA major groove with its convex surface; thelocal DNA major groove is deepest at the centre. The ß-sheetfollows 6 bp; every two residues face the DNA and the firstand fifth residues, which are separated by 13.2 Å, bind,respectively, to the third and sixth bases, which are separatedby 13.5 Å, on the same DNA strand.     

“A+一+X,B+一+Y”构式的分类及释义模板

该文以现代汉语中的“A+一+X,B+一+Y”格式为例,介绍了构建《现代汉语构式知识库》的初步工作。“A+一+X,B+一+Y”格式可根据其表义功能不同分为三个大类,十个小类。该文重点阐释了该构式表达“因果倚变义、事物交错义、状态交替义、动作行为交替义、周遍大量义、让步小量义”等6种意义的判定条件及相应的释义模板。     

Comments on the use of buckminsterfullerene encapsulated in zeolite Y as a potential catalyst

Buckminsterfullerene encapsulated within zeolite Y is found not to be a reactive radical initiator for the formation of dimethoxyethane from dimethyl ether below 200° C. Above this temperature the expected acid catalysed conversion of dimethyl ether to hydrocarbons is observed. Dimethoxyethane formation is observed when bibenzoyl peroxide is used as a radical initiator. These studies indicate that any radical formed by the encapsulated buckminsterfullerene is relatively unreactive.     

电化学沉积法制备稀土掺杂氧化钇荧光薄膜的发光性能

通过改变氧化钇薄膜中掺杂稀土元素的种类,来控制发光薄膜的荧光发射波长.利用电化学沉积法制备稀土掺杂氧化钇荧光薄膜.电化学沉积法制备的薄膜结晶效果好,掺杂离子分布较均匀,且不需要高温高压或者真空条件,成本很低.所制备的Y2O3:Ln荧光发光薄膜经XRD分析具有立方晶体结构;不同稀土掺杂的氧化钇呈现出不同的表面形貌;掺杂的Ln离子均匀地分布在薄膜中,经测试所有的Y2O3:Ln荧光发光薄膜都显示出较强的发射强度,且发光波长随着掺杂离子的不同而不同:Y2O3:Er3+发绿光,Y2O3:Ce3+发黄绿光,Y2 O3:Sm3+发蓝光,Y2O3:Pr3+发橙光.因此,电化学沉积法可用于制备具有不同发光波长的氧化钇荧光薄膜.     

频率响应法研究噻吩在CeY分子筛上的吸附行为

以NaY、液相Ce离子交换改性的Y型分子筛(L-CeY)为研究对象,运用N2吸附、XRD、NH3-TPD和Py-FTIR等实验方法表征两种Y型分子筛的物化性能。采用频率响应技术(FR)和智能重量分析仪(IGA)研究噻吩在两种分子筛上的吸附行为,并考察噻吩在稀土离子改性Y型分子筛上的不同吸附作用模式。结果表明,频率响应技术能够有效识别分子筛孔道内发生的不同传质过程。噻吩在NaY分子筛上的吸附行为较为简单,存在孔道吸附和π电子相互作用两种吸附过程;而在L-CeY分子筛上吸附行为较为复杂,同时存在孔道吸附和"S-M"吸附等多种吸附过程,另外,在高温条件下,还存在复杂的催化反应过程。     

交叉形和Y形耗能支撑钢框架滞回性能分析

为避免Y型耗能支撑钢框架在地震作用下由于耗能梁段对钢梁及楼层产生的不利影响,提出了一种改进的交叉形耗能支撑钢框架结构.采用ABAQUS6.11有限元分析软件对交形耗能支撑钢框架结构进行了滞回性能分析,并与传统Y形耗能支撑钢框架结构从水平承载力、抗侧刚度和耗能能力三方面进行了对比分析.研究表明：在设计合理的情况下,交叉形耗能支撑钢框架具有较大的抗侧刚度和良好的耗能能力,并且其强度、刚度、耗能能力均优于传统Y形耗能支撑钢框架结构.     

Preparation of Y2O3：Eu^3＋ phosphor by molten salt assisted method

A kind of fine and quasi-spherical Y2O3：Eu^3＋ phosphor was prepared by firing a preparative precursor at 1 200 ℃ for 2 h with the molten salts of Na2CO3, S and NaCl. The precursor was obtained by homogeneous precipitation of yttrium and europium with oxalic acid when using EDTA, citric acid or starch as complexant. The structure and morphology of the phosphors were characterized by XRD and SEM, respectively. The influence of complexing environment, firing temperature and molten salts on formation of the phosphor Y2O3：Eu^3＋ was discussed. The result show that the prepared Y2O3：Eu^3＋ phosphor is of quasi-spherical structure with size of 2-3 μm. Its luminescent intensity is 30% higher than that of the same phosphor prepared by the same procedure but without molten salts, and is 5% higher than that of commercial Y2O3：Eu^3＋ red phosphor.