Antimicrobial finishing of regular and modified polyethylene terephthalate fabrics

An effective two-stage method has been developed for imparting antimicrobial properties to regular polyethylene terephthalate (R-PET), polyethylene glycol modified polyethylene terephthalate (PEG-M-PET), R-PET/Cotton blend (R-PET/C) and PEG-M-PET/Cotton blend (PEG-M-PET/C) fabrics. The method consists of partial hydrolysis of the fabrics to create carboxylic groups in PET macromolecules followed by subsequent reaction with dimethylalkylbenzyl ammonium chloride (DMABAC) under alkaline conditions. The reaction conditions such as pH, reaction temperature and time, carboxylic content, and DMABAC concentration were studied. Characterization of the finished fabrics was carried out through scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). All the modified PET fabrics showed excellent antibacterial activity towards Gram-positive (Bacillus mycoides), Gram-negative (Escherichia coli), and nonfilamentous fungus (Candida albicans). The achieved antimicrobial functions on the PET fabrics are durable in repeated laundering processes. Even after laundering 10 times the fabrics could still provide more than 85% of its antimicrobial activity against B. mycoides, E. coli, and C. albicans. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Functional copolymer of geraniol and acrylonitrile: Synthesis and characterization

The radical copolymerization of acyclic terpene namely geraniol [GER] with acrylonitrile [AN] in DMF at (70 ± 0.1)°C for 1 h, using benzoylperoxide (BPO) as an initiator has been carried out under inert atmosphere of nitrogen. The kinetic expression for reaction is R_p ∝ [BPO]^0.5 [AN]^1.0 [GER]^1.0. The IR spectrum of the copolymer shows bands at 3432 and at 2244 cm^?1 due to ? OH group of GER and ? CN group of AN, respectively. The ¹³C‐NMR spectrum shows peaks at 73–75 δ ppm and 116–120 δ ppm due to ? OH group of GER and ? CN group of AN, respectively. The thermogravimetric analysis and differential scanning calorimetry study shows that copolymer is thermally stable up to 407°C and has glass transition temperatures (T_g) 56°C. The reactivity ratios r₁ (AN) and r₂ (GER) have been calculated as 0.05 and 0.005, respectively. The Alfrey‐Price Q‐e parameter for GER has been calculated as 0.094 and ?2.0, respectively. The molecular weights of the copolymers have been evaluated by gel‐permeation chromatography. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Time and temperature effect on the linear–nonlinear viscoelastic transition threshold of a polymeric system

In the present study, the transition of a polymeric material from the linear to the nonlinear viscoelastic behavior and the determination of the nonlinearity stress threshold variation with time and temperature are investigated. For this purpose a systematic experimental program consisted of thermal and mechanical characterization of certain polymeric material followed by isothermal creep tests at different stress levels and temperatures was conducted. Through isochronal curves that occurred from creep tests, the nonlinearity threshold dependence on both time and temperature is presented. The reported results provide information that is critical for the design and development of polymer structures and components. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

新区采油速度与稳产时间、递减率变化关系研究

针对新区稳产时间以及递减期递减余率大小难以确定等问题,通过对中原油田61个独立小区块进行分析对比,得出采油速度与稳产时间,不同采油速度下无因次采油速度与时间关系曲线,对于新区开发预测稳产时间以及预测递减期产量变化有着重要意义.     

一种T形高压输电线路故障测距新方法

对T形线路的故障测距，现有方法都是先判断故障支路，再将3端线路等效成2端线路进行测距。但在 T节点附近短路，尤其是经高阻短路时，现有的测距方法由于无法正确判别故障支路而存在一定范围的测距死区。针对上述缺陷，分别假设故障发生在某一支路，由假定正常的2段支路端的电压、电流推算求得 T节点电压和注入假定故障支路的电流，从而分别求得3个故障距离。经证明，求得的3个故障距离有且仅有1个在0和对应支路总长度之间，该距离就是真实的故障距离，故障发生在对应支路上。该方法无需事先判别故障支路即可测距，在 T节点附近经高阻故障时无测距死区。其测距精度理论上不受过渡电阻和故障类型影响，无需故障前数据，且对滤波无高要求。EMTP仿真结果表明该方法正确、有效，测距精度高。     

Effect of composition on gelation kinetics of unfilled and nanoapatite-filled poly(lactide-ethylene oxide-fumarate) hydrogels

Oscillatory shear rheometry at small strains was used to investigate the effects of composition (concentration of macromer, crosslinker, initiator/accelerator, and filler) on the gel point and ultimate storage modulus of poly(l-lactide-co-ethylene oxide-co-fumarate) (PLEOF) hydrogels. PLEOF in situ polymerizing hydrogels can be used as biodegradable scaffolds for cell encapsulation and tissue regeneration. The time evolution of the viscoelastic properties of the polymerizing mixture during the sol-gel transition was monitored using mechanical rheometry. According to the results, while the ultimate storage modulus linearly increased with the concentration of methylene bisacrylamide (BISAM) crosslinker, the values of the storage and loss moduli at the gel point were insensitive to the concentration of BISAM. Similar behavior was observed for PLEOF hydrogels reinforced with hydroxyapatite nanoparticles.     

A Standard Model-Theoretic Approach to Operational Semantics of Recursive Programs

In this paper we try to introduce a new approach to operational semantics of recursive programsby using ideas in the“priority method”which is a fundamental tool in Recursion Theory.In lieu ofmodelling partial functions by introducing undefined values in a traditional approach,we shall define apriority derivation tree for every term,and by respecting the rule“attacking the subterm of thehighest priority first”we define transition relations,computation sequences etc.directly based on astandard interpretation which includes no undefined value in its domain.Finally,we prove that ournew approach generates the same operational semantics as the traditional one.It is also pointed outthat we can use our strategy to refute a claim of Loeckx and Sieber that the opperational semanticsof recursive programs cannot be built based on predicate logic.     

我国金矿床氧化带的地质地球化学特征

根据氧化矿石的主要化学成分，应用ＦＡＳ图解进行氧化矿石的化学成分分类；通过对氧化带分带及发育型式的研究，建立了我国金矿氧化带形成的地质地球化学模式；对影响氧化带发育的因素进行了初步探讨。     

Effet de la pression sur la transition ruisselant-pulsé dans les réacteurs catalytiques à lit fixe arrosé

The effect of pressure on transition displacement between trickle and pulsed regimes (TPR: trickle-pulsed transition) in catalytic trickle bed reactors (CTBR) is not properly predicted by existing theoretical models and empirical correlations. Based on high pressure TPR data available to date, a modified Charpentier diagram is proposed to quantify directly the effect of pressure in non-foaming systems.