交联聚四氟乙烯的耐磨性能研究

采用电子束高温辐照制备交联聚四氟乙烯（XPTFE）,利用环-环立式万能摩擦磨损试验机在干摩擦条件下研究了PTFE和XPTFE的摩擦磨损性能变化规律。结果表明：与PTFE的摩擦系数相比,XPTFE的摩擦系数随剂量的增加而增加。随剂量的增加,XPTFE的耐磨性增大,当吸收剂量为150 kGy时,XPTFE耐磨性提高了近1 000倍。PTFE磨损表面光滑,磨屑为波浪形带状物;XPTFE的磨损表面形成摩擦棱,磨屑为粉状颗粒。XPTFE的三维网状交联结构导致其耐磨性能明显提高。     

Tailoring of chiroptical properties of substituted polyanilines by controlling steric hindrance

Optically active polyorthoanisidine, polyorthotoluidine, polyorthoethylaniline and polyorthochloroaniline were synthesized with chemical polymerization of corresponding monomers in aqueous medium by using d- or l-camphorsulfonic acid (d- or l-CSA) as chiral dopant, ammonium persulfate as oxidant, and diaminodiphenylamine as initiator. By circular dichroism spectroscopic measurements, it was found that PANI exhibited generally a reversed chirality in comparison with the used chiral dopant, but the substituted PANIs had the same one as the chiral dopant. This revealed that the substituent at ortho position caused helical inversion of conformation in comparison with the parent PANI. Such effect was further confirmed by the influence of the copolymerization of aniline and its derivatives on the chirality of the copolymers. The effect of the substituent on the chirality of the copolymers was increased with the increase of the steric hindrance of the ortho substituent. A mechanism was proposed to explain the effects of steric hindrance on the chirality of PANIs. The clarified relationship between the steric hindrance and the chirality of the polymer can enable us to tailor the chiroptical properties of functional polymer materials for future application.     

SiC反射镜表面改性研究进展

采用SiC陶瓷作反射镜是目前国际上的一个研究热点。但是SiC陶瓷用作反射镜时存在各种类型的缺点,必须对SiC反射镜表面进行改性。本文综述了各种表面改性方法、制备机理以及优缺点,最后展望了未来SiC反射镜的发展方向：即低成本化和大型化。     

Preparation of Ni/Mn compounds/ordered mesoporous carbon composite for use in an electrochemical supercapacitor

The electrochemical behavior of a series of composites synthesized by a combination of incipient wetness impregnation and hydrothermal method for the first time is systematically compared (using cyclic voltammetric and electrochemical impedance spectroscopic analyses). Structural and morphological characterizations of the composites were undertaken using power X-ray diffraction (XRD), N₂ adsorption/desorption isotherms and transmission electron microscopy (TEM). The results indicated that the binary nickel/manganese compounds of the Ni–Mn/ordered mesoporous carbon (OMC) composite had a synergistic effect of both components.     

壳聚糖絮凝剂在水处理中的应用研究进展

介绍了壳聚糖及其衍生物作为水处理絮凝剂的优势,探讨了其絮凝机理,并总结了壳聚糖及其衍生物作为絮凝剂在饮用水、城市污水、工业废水以及污泥处理中的应用研究现状.在此基础上,为壳聚糖及其衍生物作为絮凝剂的进一步研究提出了意见和建议.     

金属离子印迹改性壳聚糖对水中Ni2+的去除研究

利用金属Ni2+印迹法,通过交联和胺化反应自制Ni2+印迹改性壳聚糖吸附剂小球(P-C-CTS(Ni)),通过比较中间产品的含水率、吸附容量及FT-IR谱,分析壳聚糖在改性过程中的反应机理,验证吸附剂P-C-CTS( Ni)合成路线的正确性,并证明交联前对壳聚糖分子中的活性氨基进行保护的必要性.低浓度Ni2+(CNi=0.852 mmol·L-1)条件,考察不同酸度下吸附容量的变化和酸度对水中低浓度Ni2+去除率的影响规律.结果表明,酸度对P-C-CTS(Ni)去除重金属Ni2+效率的影响显著,酸度对Ni2+去除率的影响规律与对吸附容量的影响基本一致,并对吸附机理进行深入分析.P-C-CTS(Ni)在经过“吸附-脱附-再生”8次循环,颜色与外观等基本不变,重复使用性能稳定.     

GIS-model based estimation of nitrogen leaching from croplands of China

Nitrogen (N) is the most widely used fertilizer nutrient, and its application has increased substantially in recent decades in China. N loss through leaching has been recognized as one of the most common agricultural sources of groundwater contamination. Thus, prediction of N leaching from cropland is crucial for preventing groundwater pollution. This paper quantifies nitrogen leaching from China’s croplands, identifies its spatial distribution under current cropping systems at national scale, and finally puts forward some policies or strategies to reduce rates of N leaching. A computer process simulation model of carbon and nitrogen biogeochemistry in agro-ecosystems (DNDC) was applied to predict nitrogen leaching in the soil layer of agricultural ecosystems at national scale. Data on climate, soil properties, cropping systems, acreage, and management practices at county scale were collected from various sources and integrated into a spatial GIS database to run the model. The total amount of N-leaching was predicted at 4.57 million t N/year, which is equivalent to 48 kg N per ha cropland in 1998. The spatial distribution of N leaching in China showed a sharp discrepancy between the northern and southern counties due to the differences in climatic conditions, soil properties, as well as farm management practices. The study also suggests that applying management alternatives, such as proper fertilizer, crop, water and soil management, could be efficient means for decreasing N leaching rates.     

天津滨海新区工业园区水环境问题概述

天津滨海新区近年来发展迅猛,该地区广泛分布着以化工、冶金为主的各个工业园区,其污水排放与当地水资源环境的矛盾日益突出,逐渐对地区经济发展起到了阻碍的作用。为加大滨海新区工业园区废水治理力度,首要工作是对地区工业污水排放现状的数据和资料做摸底调查及收集分析。文章对滨海新区工业污水排放现状进行了阐述,对该地区水环境问题进行了解析,为下一步具体科研实践提出了建议方向。     

基于多媒体软件的化学化工专业英语教学模式及软件开发

结合化学化工专业英语的特点和教学经验,采用Authorware制作了化学专业多媒体教学软件,设计多个多媒体辅助教学的模块,涉及词汇记忆和发音,课文阅读,听力培养等,充分发挥软件的生动性和交互性优势,达到延伸课堂教学内容和提高教学效果的目的。     

反相气相色谱法表征HDPE的表面性质

采用反相气相色谱技术,分别测定不同分子探针在不同温度下通过高密度聚乙烯(H DPE)的保留时间,计算HDPE表面色散自由能与表面Lewis酸碱常数.HDPE表面色散自由能随温度的升高呈线性降低,且为弱碱性的Lewis两性聚合物材料.