液晶分子附着能和盒间隙对响应时间的影响

通过理论分析和实验研究液晶分子附着能和液晶盒间隙对响应时间(τ0)的影响。用液晶盒有效间隙法和表面动力学方程法两种方法推出分析公式,由这两种方法推出的结果是一致的。实验数据与简化方程τ0-dx基本拟合(其中d是液晶盒的间隙,x是指数)。在两种极端的(极大或极小)附着能极限下,指数x分别接近2和1。这个结论有助于优化液晶显示器件的应用。     

Preparation,thermal properties,and flame retardance of epoxy–silica hybrid resins

A novel epoxy system was developed through the in situ curing of bisphenol A type epoxy and 4,4′‐diaminodiphenylmethane with the sol–gel reaction of a phosphorus‐containing trimethoxysilane (DOPO–GPTMS), which was prepared from the reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) with 3‐glycidoxypropyltrimethoxysilane (GPTMS). The preparation of DOPO–GPTMS was confirmed with Fourier transform infrared, ¹H and ³¹P NMR, and elemental analysis. The resulting organic–inorganic hybrid epoxy resins exhibited a high glass‐transition temperature (167 °C), good thermal stability over 320 °C, and a high limited oxygen index of 28.5. The synergism of phosphorus and silicon on flame retardance was observed. Moreover, the kinetics of the thermal oxidative degradation of the hybrid epoxy resins were studied. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2354–2367, 2003     

An algorithm for three-way data analysis that alternatively minimizes coupled vector (COV) resolution error and PARAFAC error.

A novel algorithm, alternatively minimizing coupled vector (COV) resolution error and PARAFAC error algorithm, is proposed in this paper. This algorithm can overcome the problem of slow convergence and is insensitive to the estimation of component number, such problems are unavoidable while using the traditional parallel factors analysis (PARAFAC) algorithm. In other words, this algorithm is capable of improving the computing speed and providing accurate resolutions provided that the number of factors used in the computation is no less than that of the actual underlying ones. The characteristic performances were demonstrated with a novel fluorescence data array.     

New multifunction filter using an inverting CCII and a voltagefollower

A new multifunction filter using minimum components is presented. This filter which possesses single input and four outputs can simultaneously generate second-order highpass, bandpass, and lowpass filtering functions at individual output terminals. The filter has the following merits; it uses only two grounded capacitors which makes it suitable for integrated circuit implementation, no matching condition is required, offering multifunction outputs and has low passive and active sensitivities. Experimental results agree very well with the theoretical result     

Erratum: Preparation of size‐controlled In2O3 nanoparticles

The article referenced above was first published online on 7 August 2007 with incorrect pagination; the pagination has now been corrected online and in print. Copyright © 2007 John Wiley & Sons, Ltd.     

The relations of impregnated cathode properties to the tungsten matrix structure

Some data of emission and evaporation properties related to tungsten matrix structures of the impregnated cathodes are analyzed. The results indicate that the particle size of tungsten powder and the pore size in the porous matrix determine the total inside surface area of all pores, the diffusion length of barium atoms over tungsten grain surfaces, and the diameter and length of the path through which barium atoms are transported. These factors all relate to the properties and operation mechanism of an impregnated cathode; therefore, it would not be strictly correct to use only the matrix porosity for characterizing the cathode properties. Finally, the preferred structures of porous tungsten matrix depending on different applications of impregnated, cathodes are proposed.     

Plant tissue-based chemiluminescence biosensor for ethanol.

A plant tissue-based chemiluminescence biosensor for ethanol based on using mushroom (Agaricus bisporus) tissue as the recognition element is proposed in this paper. The principle for ethanol sensing relies on the luminol-potassium hexacyanoferrate(III)-hydrogen peroxide transducer reaction, in which hydrogen peroxide is produced from the ethanol enzymatic catalytic oxidation by oxygen under the catalysis of alcohol oxidase in the tissue column. Under optimum conditions, the method allowed the measurement of ethanol in the range of 0.001 - 2 mmol/l with a detection limit (3 sigma) of 0.2 micromol/l. The relative standard deviation (RSD) was 4.14% (n = 11) for 0.05 mmol/l ethanol. The proposed method has been applied to the determination of ethanol in biological fluids and beverages with satisfactory results.     

Synthesis and application as polymer electrolyte of hyperbranched polyether made by cationic ring‐opening polymerization of 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxymethyl}‐3′‐methyl‐oxetane

A novel cyclic ether monomer 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy‐methyl}‐3′‐methyloxetane (HEMO) was prepared from the reaction of 3‐hydroxymethyl‐3′‐methyloxetane tosylate with triethylene glycol. The corresponding hyperbranched polyether (PHEMO) was synthesized using BF₃·Et₂O as initiator through cationic ring‐opening polymerization. The evidence from ¹H and ¹³C NMR analyses revealed that the hyperbranched structure is constructed by the competition between two chain propagation mechanisms, i.e. active chain end and activated monomer mechanism. The terminal structure of PHEMO with a cyclic fragment was definitely detected by MALDI‐TOF measurement. A DSC test implied that the resulting polyether has excellent segment motion performance potentially beneficial for the ion transport of polymer electrolytes. Moreover, a TGA assay showed that this hyperbranched polymer possesses high thermostability as compared to its liquid counterpart. The ion conductivity was measured to reach 5.6 × 10^?5 S/cm at room temperature and 6.3 × 10^?4 S/cm at 80 °C after doped with LiTFSI at a ratio of Li:O = 0.05, presenting the promise to meet the practical requirement of lithium ion batteries for polymer electrolytes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3650–3665, 2006     

Synthesis,characterization, and electrical properties of polypyrrole/multiwalled carbon nanotube composites

Size‐controllable polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT) composites have been synthesized by in situ chemical oxidation polymerization directed by various concentrations of cationic surfactant cetyltrimethylammonium bromide (CTAB). Raman spectra, FTIR, SEM, and TEM were used to characterize their structure and morphology. These results showed that the composites are core (MWCNT)–shell (PPy) tubular structures with the thickness of the PPy layer in the range of 20–40 nm, depending on the concentration of CTAB. Raman and FTIR spectra of the composites are almost identical to those of PPy alone. The electrical conductivities of these composites are 1–2 orders of magnitude higher than those of PPy without MWCNTs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6449–6457, 2006