Structure and Properties of Self-reinforced Material Made from Ultra-high Molecular Weight Polyethylene-montmorillonite Nanocomposite

High-strength and high-modulus ultra-high molecular weight polyethylene (UHMWPE), named self-re-inforced material, was obtained by the elongation of UHMWPE-montmorillonite nanocomposite at melting temperature. According to the scanning electron microscope (SEM) analysis, a great deal of fibrillar texture formed in the direction of elongation, and the tensile fractured surface was similar to that of highly oriented fiber. The transmission electron microscope (TEM) and selective area electron diffraction (SAED) analyses reveal that the reinforced phase of the self-reinforced material is an extended chain crystal and its size is about 50--200 nm wide and several microns long, and the montmorillonite layers are broken up to pieces in the size from 100 to 10 nm. The broken layers which have a huge surface area interacting strongly with macro-molecules reduces the entanglement density of UHMWPE and induces the chain orientation in flow field. It is supposed that the astriction of montmorillonite layers to polyethylene chains is not only end-tethered but also side-tethered. The differential scan calorimetry(DSC) analysis shows that there are two endothermal peaks for the self-reinforced material, of which the peak at a higher temperature(136.4℃) is ascribed to the melt-ing of the reinforced phase.     

Pretreatment of Polymer-Supported Pd-Co and Its Catalytic Activity

l/or if llctcrogclleous catalyst, it is c('lllllloll that dillbrcnt 1llcthods of preparation result ina dillbrcllcc ill tile catalytic activity, altllotlgll its composition is the same. For atriltlitiotlill if')lllogctlcolls catalyst witll ljxc(l c(f)lllpositioll, its catalytic activity usuallydt)es hot cllallgc Witll tile llletllod elf l,l'cl,arutioll. I'olylller-supported catalysts are calledtile lletcrogcllizc(1 llolllogcllcolls catalysts that colllbille the nlcrits of h()1llogcncous andllc…     

7-表-γ-桉叶油醇的不对称全合成

桉烷型倍半萜类化合物广泛分布于自然界中, 普遍具有昆虫拒食、植物生长调节、细胞生长抑制等生物活性[1～3], 因此, 近年来越来越受到有机化学家的重视. 最近, 法国学者Ramanoelina等[4]从传统药用植物Laggera alata var. Alata Sch. Bip. Ex oliv.中分离得到的两个新的此类化合物: 7-表-γ-桉叶油醇(1)和7-表-β-桉叶油醇(2), 它们的合成均未见报道, 其结构如下式.     

电子探针图像的实用处理软件

基于Ｗｉｎｄｏｗｓ９５操作平台,用ＶｉｓｕａｌＣ＾＋＋５．０语言开发了电子探针图像实用处理软件,可对数字电子探针图像进行颜色转换、图像合成、内插放大、三维视图、直方图、灰度级切片、灰度级反转、灰度级平移、灰度级映射、平滑和锐化等自理灵活地运用这些处理技术,能够有效地突出数字电子探针图像中任何感兴趣信息、改善图像质量、增强视觉效果,其中,合成图像是一种表达矿物组分信息的新方法。     

N-含硒壳聚糖衍生物的合成、表征及其生物活性

通过壳聚糖分子上的－ＮＨ２基与三种有机硒化合物邻甲硒基苯甲硒基苯甲酸对硝基苯酚酯、２－（４－苯甲酸甲酯基）－１,２－苯并异硒唑－３（２Ｈ）酮和硒代二乙酸反应,使有机硒分子片接枝到高分子壳聚糖上,合成了三种新的Ｎ－含硒壳聚糖衍生物。经元素分析,ＩＲ和ＵＶ分析表征了其结构。实验结果表明,Ｎ－含硒壳聚糖衍生物与预期结构相符。初步动物实验表明其具有一定的生物活性;抗脂质活性和抗肿瘤活性。     

弱视儿童血铅测定情况分析

探讨了血铅水平与儿童弱视的关系。分别检测了弱视儿童42例及正常对照儿童30例的血铅水平。结果表明,弱视组铅中毒人数明显高于正常组,差异有显著性。提示铅中毒儿童具有视觉发育障碍的高风险性,应重视患和的眼科随访工作,防治弱视。     

光纤电压传感器温度特性的研究

以半波电压较高的石英晶体为敏感材料,分析了光纤电压传感器全量程的温度特性,发现其与传感器所测电压值要关;随着待测电压的从小往大增加,其输出温度变化的灵敏度逐渐由小变大。为了实现电压传感器全量程的温度补偿,必须获取两个关键的参数：一为电压传感器在无外加电压作用下的温度输出响应参数;二是敏感材料在电压作用下的温度应参数。     

Mechanism for the Correlated Swinging of Photoluminescence Intensity and Peak Energy Shift with Sizes of Nanoscale Si Particles

Based on the quantum confinement-luminescence center model, we focus on the relationship between the photoluminescence (PL) spectra and sizes of nanoscale silicon particles.We find that when there are two kinds of luminescence centers (LC) in the oxide layer surrounding the silicon particles, both the integrated PL intensity and the spectral peak position swing with reducing the sizes of silicon particles, which is different from the monotonous blueshift of peak position predicted by quantum confinement model. By changing the concentrations of LC we find the correlation between the spectral peak position and the integrated PL intensity when the size of silicon particles is reduced. The effects of other parameters such as the half width of size distribution and the position of photon emission levels of LC are also found to be important.     

DVB传输流捕获系统的实现

研究了DVB传输流实时捕获系统的结构及其实现方法．该系统的硬件利用复杂可编程逻辑器件和总线接口芯片,实现了传输流与PcI总线之间的接口,软件利用设备驱动程序将硬件采集的数据流传入计算机．同时保证了高速的数据交换速率,可以对捕获的数据流进行实时的处理,该系统在DvB的分析、测试、存储、编辑和复用中都有着广阔的应用前景．     

光纤同轴电缆混合网技术

阐述了光纤同轴电缆混合网 (HFC)网络的主要工作原理 ,给出了 HFC网络的基本结构模型 .对 HFC网络媒体存取控制 (MAC)层中的 3个重要问题 ,即上行通道访问模式、同步问题、碰撞解决方案及其解决方案进行了讨论 ,并对 HFC技术中存在的噪声干扰问题以及解决办法进行了初步的探讨 .