Grafting of PNIPAAm on PVDF submicroscopic tracks induced by the active sites remainders of the etching process

The present work is part of a systematic study that involves different polymeric substrates and monomers with the purpose to induce grafting on etched tracks. The residual active sites produced by heavy ion beams, remaining after the etching process, were used to start the grafting process. In order to produce tracks on foils of poly(vinylidene fluoride) (PVDF) they were irradiated with ²⁰⁸Pb of 25.62 MeV/n or with 115 MeV Cl ions. Then, they were etched and grafted with N-isopropylacrylamide (NIPAAm) monomers. Experimental curves of grafting yield as a function of fluence with the etching time as a parameter were measured. Also, the grafting yield as a function of the grafting and etching time was obtained. The replica method allowed the observation of the shape of the grafted tracks using transmission electron microscopy (TEM). In addition NIPAAm grafted foils were analyzed using Fourier transform infrared spectroscopy (FTIR).     

Microsomal cytochrome P450-3A4 (CYP3A4) nanobiosensor for the determination of 2,4-dichlorophenol—An endocrine disruptor compound

Cytochrome P450-3A4 (CYP3A4) is a monooxygenase enzyme that plays a major role in the detoxification of bioactive compounds and hydrophobic xenobiotics (e.g. medicines, drugs, environmental pollutants, food supplements and steroids). Physiologically the monooxygenation reactions of this class II, microsomal, b-type heme enzyme, usually requires cytochrome P450 reductase, NADPH. A novel CYP3A4 biosensor system that essentially simplified the enzymatic redox processes by allowing electron transfer between the electrode and the enzyme redox centre to occur, without any need for the physiological redox partners, was developed for the detection of 2,4-dichlorophenol (2,4-DCP), a priority environmental pollutant and an endocrine disruptor. The biosensor, GC/Naf-Co(Sep)³⁺/CYP3A4/Naf, was constructed by encapsulating CYP3A4 in a Nafion-cobalt (III) sepulchrate (Naf-Co(Sep)³⁺) composite film on a glassy carbon (GC) electrode. The responses of the biosensor to 2,4-dichlorophenol, erythromycin (CYP3A4 native substrate) and ketoconazole (CYP 3A4 natural inhibitor) were studied by cyclic and square wave voltammetric techniques. The detection limit (DL) of the biosensor for 2,4-dichlorophenol was 0.043 μg L⁻¹, which is by an order of magnitude lower than the EU limit (0.3 μg L⁻¹) for any pesticide compound in ground water. The biosensor's DL is lower than the U.S. Environmental Protection Agency's drinking water equivalent level (DWEL) value for 2,4-DCP, which is 2 μg L⁻¹.     

分布式非结构化P2P网络中的搜索技术优化

研究介绍一种可选择的Gnutella的搜索算法和数据复制策略。它是一种多次随机漫步(multiple random walks)搜索算法,跟洪泛的搜索算法一样快,但是减少了网络的负载量。     

SEM in-situ Fatigue Observation on Crack Initiation and Growth from Inclusion in P/M Rene95 Superalloy

A special designed experiment was conducted for observing crack initiation and growth in P/M Rene9S superalloy under ten- sion-tension loading by self-made SEM in-situ fatigue loading stag. Several alumina inclusion particles exposed at the specimen surface were observed carefully. During fatigue test inclusions led to cracks initiation. The cracks can be formed by two mechanisms. Generally, the cracks nucleated at the interface between inclusion and matrix. Sometimes, cracks were also formed inside the inclusion. As the in- crease of cycles, some cracks at the interface between inclusion and matrix broadened and propagated along the direction about 45° to the loading axis. On the other hand, the cracks inside the inclusion propagated in the inclusion and towards matrix.     

P2P下载技术在嵌入式设备中的应用

嵌入式系统作为一种低功耗,微内核设备以及本身的硬件限制等各种特点,开发在一种具有下载功能的嵌入式设备很具有商业意义。传统的下载方式是节点和服务器之间交换信息,而P2P技术与传统的C/S方式有很大不同,它允许节点之间直接交换信息,很适合嵌入式系统之中。下本文通过对amule了进行移植,分析了交叉编译环境的搭建,嵌入式调试中的调试技术以及交叉编译过程中遇到的各种问题,成功实现了MIPS平台下的P2P文件共享技术,此外本文还用简洁的语言给出了一个完整的嵌入式开发流程。     

Characterizations of some classes of spiking neural P systems

We look at the recently introduced neural-like systems, called SN P systems. These systems incorporate the ideas of spiking neurons into membrane computing. We study various classes and characterize their computing power and complexity. In particular, we analyze asynchronous and sequential SN P systems and present some conditions under which they become (non-)universal. The non-universal variants are characterized by monotonic counter machines and partially blind counter machines and, hence, have many decidable properties. We also investigate the language-generating capability of SN P systems.     

国外钻井技术发展现状

美国及西欧一些发达国家一直处于钻井技术的前列，了解国外钻井技术现状，利于我国们在战略上决策钻井科技发展的方向，本文首先概述了国外比较成熟的大位移井钻井、欠平衡钻井、小井眼钻井、超深井钻井、老井重钻等技术，对国外正在研究和开发的钻井技术，如分枝井钻井技术、连续管技术、旋转导向钻井系统、套管钻井工艺、三维可视化技术等也作了一定介绍，对促进我国钻井技术的发展具有一定的借鉴意义。     

用等离子体处理后硅橡胶的表面氧化

用不同功率和作用时间的等离子体处理户外绝缘用硅橡胶。用ＸＰＳ技术分析了处理后硅橡胶表面成分的变化。结果表明，等离子体处理后的硅橡胶表面“有机硅”含量降低，“无机硅”含量增加，导致硅橡胶表面的Ｃ含量降低，Ｏ、Ｓｉ含量增加，探讨了硅橡胶的老化机理。