Pa-239 may influence astrophysics study

The estimation method of the universe age using the nuclear cosmochronology by the heavy chronometers is essentialized. The influence of the novel long half-life of Pa-239 on the universe age estimation is simply mentioned.

Properties of ethylene-propylene copolymer/PA-1010 blends using ethylene-propylene copolymer-graft-acrylic acid as a compatibilizing agent

The modification of ethylene-propylene copolymer (EP) has been accomplished by radical EP-graft-acrylic acid (EP-g-AA) has been used to obtain ternary PA/EP/EP-g-AA blends by melt mixing. Different blend morphologies were observed by scanning electron microscopy; the domain size of the EP-dispersed phase in the polyamide 1010 matrix of compatibilized blends decreased compared with that of uncompatibilized blends. It is found that EP-g-AA used as the third component has a profound effect on the mechanical properties of the resulting blends. This behavior has been attributed to serious chemical interactions taking place between the two components. Thermal analysis shows that some thermal properties of PA in compatibilized PA/EP/EP-g-AA changed because of chemical reactions taken place during the blending process. Wide angle x-ray diffraction measurements also confirmed this result. (C) 1996 John Wiley & Sons, Inc.

辐射交联型PA－66机械物理性能研究

本文讨论了进口与国产ＰＡ—６６经钴源辐射交联后，对机械物理性能产生的影响。发现适量经辐射的ＰＡ—６６球压硬度、拉伸强度、Ｉｚｏｄ冲击强度都有较大幅度提高，并在１００，０００Ｇｙ剂量对达最大值，而断裂伸长率在１００，０００Ｇｙ剂量以下变化不大。国产ＰＡ—６６辐射后在乙二醇中，在２５０℃时，２小时不起层，性能变化不大，可替代进口材料。

SYNTHESIS AND CHARACTERIZATION OF HIGH-PERFORMANCE PA FILM

I. INTRODUCTIONIn last decade, considerable attention was focused on polyacetylene. However, its practical application was affected considerably because of its poor strength and stability. Recently, Narrmann et al. reported that they could synthesize PA film with improved properties using modified Ziegler-Natta catalyst. However, no detailed

Recombinant expression of rt-PA gene (encoding Reteplase) in gametophytes of the seaweed Laminaria japonica (Laminariales, Phaeophyta)

The life cycle of seaweed Laminaria japonica involves a generation alternation between diploid sporophyte and haploid gametophte. The expression of foreign genes in sporophte has been proved. In this research, the recombinant expression in gametophyte was investigated by particle bombardment with the rt-PA gene encoding the recombinant human tissue-type plasminogen activator (Reteplase), which is a thrombolytic agent for acute myocardial infarction (AMI). Transgenic gametophytes were selected by their resistance to herbicide phosphiothricin (PPT), and proliferated in an established bubble column photo-bioreactor. According to the results from quantitative ELISA, Southern blotting, and fibrin agarose plate assay (FAPA) for bioactivity, it was showed that the rt-PA gene had been integrated into the genome of gametophytes of L. japonica, and the expression product showed the expected bioactivity, implying the proper post-transcript modification in haploid gametophyte.

第十四章 WIA-PA:用于过程自动化的工业无线网络系统结构与通信规范

概要介绍工业无线网络的标准化进程,详细介绍了用于过程自动化的工业无线网络WIA规范的网络构成、拓扑结构、协议体系和关键技术,并将WIA-PA与WirelessHART、ISASP100两大工业无线标准进行了比较分析。

PROFIBUS PA通信协议软件开发

随着控制技术、计算机技术、通信技术的飞速发展，现场总线技术正逐渐取代集散控制技术。PROFIBUS现场总线技术作为应用最为广泛的现场总线技术之一，截止至2008年8月，其安装节点已经超过2500万个，市场份额超过20%。 本文首先深入研究了现场总线国际标准IEC61158-Type3(PROFIBUS标准)，分析了PFOFIBUS 现场总线的层次结构模型、各层功能及层间通信关系，然后介绍了PROFIBUS PA的功能块模型，包括块的构成、分类、参数详解，以及把功能块模型映射到模块化DP从站设备的规则等。然后本文采用uC/OS-II嵌入式实时操作系统作为软件平台，应用瑞萨公司M16C/62P系列MCU与中科院沈阳自动化研究所自主研发的FBC0409现场总线通信控制器作为硬件平台，开发了支持PROFIBUS DPV0和DP V1的通信协议栈，并根据PA应用行规(V3.01)编写了相应的功能块程序，并且进行了验证。 本文给出了PROFIBUS DPV0、DPV1实现过程中的主要数据和功能定义，介绍了各层任务的创建初始化，处理过程，绘制了相关的软件流程图。本文给出了编写物理块、功能块、变换块和设备管理的参数定义和读写函数的方法。