几种无机纤维的性能对比

介绍了玄武岩纤维、玻璃纤维、碳纤维及其性能,主要目的是对这些纤维性能进行测试与对比,并对测试结果进行比较。     

高g值加速度冲击试验技术研究

摘 要：根据弹体高速侵彻硬目标过程中加速度测试的特点,研制了高g值冲击试验装置。它由一级空气炮、加速度存储测试装置、炮弹、反射式激光测速仪和激光多普勒测速仪等组成,并在该冲击试验装置上进行了弹载加速度存储测试装置的高g值冲击试验。采用泡沫铝缓冲件对记录电路模块进行缓冲保护,利用光栅作为合作目标,由两套激光多普勒测速仪同时记录冲击过程中测试装置外壳和电路模块的激光频移信号, 处理可得到二者的加速度——时间曲线,比较了泡沫铝的高g值缓冲效果。     

中间包镁质涂抹料和定径水口快换技术的应用

介绍了连铸中间包镁质涂料和定径水口快换技术及快换的原理在长钢的应用情况和效果。     

面向Oracle 11g的语义查询集成平台

在VOEditor本体可视化编辑器的基础上,结合本体的相关知识,采用Oracle 11g和其他推理引擎的语义技术,开发一个基于语义的信息查询集成平台原型系统,介绍其体系结构、主要查询机制、实现技术及初步使用情况。结果表明,该系统能对知识库进行不同程度的推理查询,并能支持大型的语义应用。     

A Novel Topological Index F and Its Correlation With Standard Formaton Enthalpies of AB_n(g) Molecules

The topological index F* is defined and obtained by the method of a non-dimensional unit calculation in which three matrices multiply with each other. These matrices represent the connective cases of atoms in a molecule, the structural features of atoms on top and the bonded cases of the adjacent atoms respectively. The standard formation enthalpies of ABn(g) molecules were correlated with F'* (A = C, Al, Si, Ti, Zr, B = F, Cl, Br, I, H, n=1 -4) and these correlation coefficients are all more than 0.96. Some molecules (e.g CH4, SiH4,etc. )can be preferably handled by F* but can not be dealt with by other topological indices. By contrast to traditional hydrogen suppressed graph, the contribution of hydrogen atoms to structures and properties of molecules is considered.     

一种基于OFDM的新型低功耗RF收发器设计

为实现低功耗信号传输,提出一种基于OFDM的IEEE 802.15.4g低功耗无线电频率（RF）收发器。该新型RF收发器电路由Tx BBA（基带模拟）、片上RF开关前端、Rx BBA及锁相环（PLL）构成,采用0.18?m CMOS技术制作,满足了IEEE 802.15.4g OFDM系统低功耗信号传输的需要。实际测试结果显示,相比传统的RF收发器,提出的RF收发器具有较低的功耗和良好的灵敏度,当电源电压为1.8 V时,Tx模式下会消耗14.7mA,Rx模式下会消耗15.7mA。     

基于并行干扰抵消的5G通信信道传输控制系统设计

为解决5G通信信号的连接超时问题,使其在单帧、多帧、连续帧情况下,均能呈现出较为流畅的传输状态,设计基于并行干扰抵消的5G通信信道传输控制系统;联合主电源模块与通信信号采集模块,并将输出控制结构、数据处理结构接入电源平台的既定控制节点之中,完成5G通信信道传输控制系统的功能方案设计;在此基础上,分析5G通信信道内的信号传输环境,通过设置并行干扰抵消检测器的方式,得到残余多址信息的表达结果,完成基于并行干扰抵消的5G通信信道配置;根据干扰方差计算表达式,确定5G通信信号的传输误码率水平,实现对系统控制指令的分析与研究,结合相关硬件设备结构,完成基于并行干扰抵消的5G通信信道传输控制系统设计;实验结果显示,与动态无线控制系统相比,在并行干扰抵消算法作用下,5G通信信号在单帧、多帧、连续帧情况下的连接时长均能得到较好控制,这对于信号参量的流畅传输能够起到一定的促进性影响作用。     

鄂尔多斯盆地地层水的配伍性研究

通过对中国图书馆分类法和中国科学院图书馆图书分类法及测绘学叙词表等相关资料的分析,确定本体中的类和定义类的语义关系,基于Protégé工具构建测绘学科信息公共本体、测绘学科分类—中图法本体及测绘学科分类—科图法本体,在构建的本体基础上基于Oracle 11g语义技术构建测绘学科分类本体库,为进一步语义检索提供基础.     

Relation between microstructure and glass transition temperature of poly[(methyl methacrylate)‐co‐(ethyl acrylate)]

The glass transition temperature of a series of samples of the poly[(methyl methacrylate)‐gt;cogt;‐(ethyl acrylate)] copolymer, synthesized at low conversion, were calculated theoretically using the equations of Barton and Johnston. The values obtained are more precise when the probabilities of the compositional diads are derived from the gt;13gt;C NMR data instead of the classical method utilizing reactivity ratios. This can be observed more clearly when the copolymer samples are synthesized at high conversion. Introduction of configuration (tacticity) at the diad level confirms the above observations and slightly improves the calculated values of gt;Tgt;gt;ggt; compared to the initial formulae which were only taking into account the compositional sequences of the copolymer. © 2001 Society of Chemical Industry     

Urinary mercury in people living near point sources of mercury emissions

As part of the European Mercury Emissions from Chlor Alkali Plants (EMECAP) project, we tested the hypothesis that contamination of ambient air with mercury around chlor alkali plants using mercury cells would increase the internal dose of mercury in people living close to the plants. Mercury in urine (U-Hg) was determined in 225 individuals living near a Swedish or an Italian chlor alkali plant, and in 256 age- and sex-matched individuals from two reference areas. Other factors possibly affecting mercury exposure were examined. Emissions and concentrations of total gaseous mercury (TGM) around the plants were measured and modeled. No increase in U-Hg could be demonstrated in the populations living close to the plants. This was the case also when the comparison was restricted to subjects with no dental amalgam and low fish consumption. The emissions of mercury to air doubled the background level, but contributed only about 2 ng/m(3) to long-term averages in the residential areas. The median U-Hg levels in subjects with dental amalgam were 1.2 microg/g creatinine (micro/gC) in Italy and 0.6 microg/gC in Sweden. In individuals without dental amalgam, the medians were 0.9 microg/gC and 0.2 microg/gC, respectively. The number of amalgam fillings, as well as chewing, fish consumption, and female sex were associated with higher U-Hg. The difference between the countries is probably due to higher fish consumption in Italy, demethylated methyl mercury (MeHg) being partly excreted in urine. Post hoc power calculations showed that if the background mercury exposure is low it may be possible to demonstrate an increase in U-Hg of as little as about 10 ng/m(3) as a contribution to ambient mercury from a point source.