SYNTHESIS AND PROPERTIES OF SULFONATED POLY（ARYLENE ETHER） CONTAINING TRIPHENYL METHANE MOIETIES FROM ISOCYNATE MASKED BISPHENOL

A novel sulfonated poly（arylene ether） containing triphenylmethane moieties was synthesized by the sulfonation of a designed parent polymer using chlorosulfonic acid as sulfonation agent. The sulfonation took place at the para position of the pendant phenyl rings because of the specially designed parent polymer. The position and degree of sulfonation were characterized by ^1H-NMR and elemental analysis. The sulfonated polymers are highly soluble in common organic solvents, such as dimethylsulfoxide, N,N＇-dimethylacetamide, dimethylformamide, ethylene glycol monomethyl ether, and can be readily cast into tough and smooth films from solutions. The films showed good thermal and hydrolysis stabilities. Moreover, Fenton＇s reagent test revealed that the films exhibited superior stability to oxidation. The proton conductivities of the films were comparable with Nation 117 under same conditions. The membrane electrode assembly （MEA） prepared with the asmade film （706 EW, 100 μm dry thickness） shows better cell performance than Nation 115-MEA in the whole current density range.     

Sample capacity in open tubular and micro-packed columns for GC

Equations have been derived from which the maximum sample size which may be loaded on a column without significantly affecting the performance may be calculated. It is shown that micro-packed columns can handle a sample which is as much as forty times larger than that which can be loaded onto wall-coated open tubular columns with comparable conditions.     

On the equivalence of the BLUEs under a general linear model and its restricted and stochastically restricted models

Necessary and sufficient conditions are derived for the equalities of the best linear unbiased estimators (BLUEs) of parametric functions under a general linear model and its restricted and stochastically restricted models to hold.     

Existence of almost periodic solutions to some stochastic differential equations

The article introduces and studies the concept of p-mean almost periodicity for stochastic processes. Our abstract results are, subsequently, applied to studying the existence of square-mean almost periodic solutions to some semilinear stochastic equations.     

一类随机微分方程的稳定性

本文用Rn中一类半线性椭圆方程正解结果讨论了随机微分方程的随机稳定性.     

Positive solution and its asymptotic behaviour of stochastic functional Kolmogorov-type system

In general, population systems are often subject to environmental noise. This paper considers the stochastic functional Kolmogorov-type system

     

Ge掺杂β-Ga2O3晶体的发光性能研究

采用浮区法(FZ)生长Ge掺杂β-Ga2O3晶体,利用XRD和Raman光谱研究了掺杂对晶体结构的影响.透射光谱测试表明,随着Ge离子掺杂浓度增加,Ge∶ β-Ga2O3晶体光学带隙增大.在4.67 eV紫外光激发下,Ge∶ β-Ga2O3晶体的发光强度与β-Ga2O3晶体相当,发光衰减时间比β-Ga2O3晶体更快.     

Preface: Current research progress on mechanics of high speed rail

The construction and operation of high-speed rail（HSR）grid within the past two decades in China,in terms of the scale,may be possibly comparable to any national-wide construction in the history of China,even the Great Wall.By counting railways with commercial train service at the speed of200 km/h,China has the world’s longest HSR network with over 19 369.8 km of track in service today and this number     

Determination of alcohols in gasoline blends using a multi-dimensional switching system

Methanol, 2-Me-propanol-2, propanol-2, benzene, toluene and xylenes in gasoline blends were determined using a valveless multi-dimensional switching system (MDSS) with two packed columns and temperature programming. Compounds of interest, interfering with paraffins and naphthenes, were in a sequence of four heart cuts transferred onto the second column. The resulting baseline separation enabled precise quantitative measurement within a short analysis time. Instrument settings, times of switching and integration parameters were stored in an instrument memory file (user table) and thus high precision in the measurements was achieved.