废轮胎回转窑中试热解炭的重金属离子吸附特性

对废轮胎回转窑中试热解炭的重金属离子Pb2＋、Cr3＋和Cr6＋吸附特性进行了研究，分析了溶液pH值、接触时间、吸附剂用量以及溶液初始浓度对重金属去除率的影响。结果表明，溶液pH值对热解炭的重金属去除率有显著影响，阳离子Pb2＋、Cr3＋的去除率随pH的增加而增大，在弱酸和中性环境中去除率接近100％；Cr6＋在强酸性溶液中被还原成为Cr3＋，经二次吸附，总Cr去除率可达99％以上；Pb2＋和Cr3＋的去除率随热解炭用量和吸附时间的增大而增加，热解炭用量和吸附时间有一个最佳值。Pb2＋和Cr3＋的吸附为单分子层吸附，可用Langnuir和两段Freundlich等温吸附式描述，Freundlich拟合指数表明，热解炭具有较好的吸附性能。经酸洗后的热解炭对Pb2＋的去除率变低。     

Effects of microcracks on the poroelastic behaviors of a single osteon

It has been suggested that microcracks do play a key role in the triggering of the bone remodeling process. In order to evaluate the influence of microcracks on the poroelastic behaviors of an osteon, a finite element model is established and investigated by using the Comsol Multiphysics software. The findings show that the presence of a microcrack in the osteon wall strongly modifies (enlarges) its local fluid pressure and velocity. Especially, the pressure and velocity amplitudes produced in the microcracked region are larger than those of the non-cracked region. Thus, this study can also be used for proposing a likely mechanism that bone can sense the changes of surrounding mechanical environments.     

Near-field infrared response of graphene on copper substrate

The electronic properties of graphene are very sensitive to its dielectric environment. The coupling to a metal substrate can give rise to many novel quantum effects in graphene, such as band renormalization and plasmons with unusual properties, which are of high technological interest. Infrared nanoimaging are very suitable for exploring these effects considering their energy and length scales. Here, we report near-field infrared nanoimaging studies of graphene on copper synthesized by chemical vapor deposition. Remarkably, our measurements reveal three different types of near-field optical responses of graphene, which are very distinct from the near-field edge fringes observed in the substrate. These results can be understood from the modification of optical conductivity of graphene due to its coupling with the substrate. Our work provides a framework for identifying the near-field response of graphene in graphene/metal systems and paves the way for studying their novel physics and potential applications.     

Sensitive detection of H(2)O(2) and H(2)O(2)-related reactant with Ru(bipy)(2)(7,8-dimethyl-dipyridophenazine)(2+) and oligodeoxyribonucleotide

A sensor for H(2)O(2) and H(2)O(2)-related reactant was constructed with oligonucleotides and Ru(bipy)(2)dppx(2+) (bipy = 2,2'-bipyridine, dppx = 7,8-dimethyl-dipyridophenazine), which was performed by converting the H(2)O(2)-induced DNA cleavage into the change of luminescence. The 'DNA light switch' Ru(bipy)(2)dppx(2+) could emit strong luminescence in the presence of dsDNA. DNA cleavage occurred upon addition of H(2)O(2) due to the Fenton reaction, which resulted in the decrease of the luminescence of Ru(bipy)(2)dppx(2+). Therefore, the luminescence intensity depended on the concentration of H(2)O(2) and H(2)O(2)-related reactants, and the detection limits for H(2)O(2), uric acid and cholesterol were 0.20 μM, 0.46 μM and 1.25 μM, respectively. The recovery varied between 94.0% and 105.0% when the assay was applied to the determination of uric acid and cholesterol in biological samples, which demonstrated the good practicability of the assay.     

Conductivity exponent in three-dimensional percolation by diffusion based on molecular trajectory algorithm and blind-ant rules

Diffusion on random systems above and at their percolation threshold in three dimensions is carried out by a molecular trajectory method and a simple lattice random walk method, respectively. The classical regimes of diffusion on percolation near the threshold are observed in our simulations by both methods. Our Monte Carlo simulations by the simple lattice random walk method give the conductivity exponent μ/ν=2.32±0.02 for diffusion on the incipient infinite clusters and μ/ν=2.21±0.03 for diffusion on a percolating lattice above the threshold. However, while diffusion is performed by the molecular trajectory algorithm either on the incipient infinite clusters or on a percolating lattice above the threshold, the result is found to be μ/ν=2.26±0.02. In addition, it takes less time step for diffusion based on the molecular trajectory algorithm to reach the asymptotic limit comparing with the simple lattice random walk.     

藏药珠西的化学成分与结构分析

采用X射线荧光(XRF)、电感耦合等离子体发射光谱(ICP-OES)和X射线衍射(XRD)对不同来源藏药珠西中的元素成分和结构组成进行测定,以期揭示其药理作用的物质基础。XRF和ICP-OES分析结果表明,藏药珠西中主要元素为Fe,S和O,及少量的Si,Na,Mg,Al,K,Ni,Ca,Ti等元素。XRD分析表明,藏药珠西中主要存在立方晶系FeS2,此外还含有少量的斜方晶系Fe+3O(OH)等。通过XRF,ICP-OES和XRD分析,获得了藏药珠西的化学成分和结构组成基本数据,为其药理作用物质基础的揭示和质量标准的制定提供了科学依据。     

关于部分偏振光能量传递和偏振态的光线椭圆分析方法

部分偏振光传播时的光强和偏振态变化情况比较复杂, 尤其是当大数值孔径成像时, 光束的偏振态还会影响成像质量. 本文提出一种用于分析部分偏振光能量传递和偏振态的光线椭圆方法, 采用光线椭圆叠加的办法来分析光束在各向同性的均匀介质中传输时能量和偏振态的变化情况, 同时直观性好, 计算量小. 论文最后, 对大数值孔径、 高像质的齐明透镜系统讨论了入射无偏振光的能量、 偏振态变化, 以及偏振效应问题. 结果表明, 大数值孔径使成像光束中TM偏振光强度相对增加, 影响成像对比度; 提高像方介质的折射率, 会改善此种偏振效应问题.     

弹塑性结构安定下限分析的无网格局部Petrov-Galerkin法

将基于Voronoi结构的无网格局部Petrov-Galerkin法与减缩基技术相结合,建立了一种安定下限分析的新方法.为了克服移动最小二乘近似难以准确施加本质边界条件的缺点,采用了自然邻近插值构造试函数.通过引入基准载荷域上载荷角点的概念,消除了安定下限分析中由时间参数所引起的求解困难.利用减缩基技术,将安定分析问题化为一系列未知变量较少的非线性规划子问题.在每个非线性规划子问题中,自平衡应力场由一组带有待定系数的自平衡应力场基矢量的线性组合进行模拟,而这些自平衡应力场基矢量可应用弹塑性增鼍分析中的平衡迭代结果得到.算例结果汪明了提出的分析方法的有效性.     

海藻多糖的组成及结构光谱分析

海藻多糖具有抗凝血等多种生物活性,其活性与多糖的组成结构有关。本文对近年来红藻、褐藻及少量绿藻多糖的单糖组成及含量研究以及FT-IR和12^C NMR两种主要光谱手段对多糖结构研究的结果进行了介绍。     

煤在燃烧过程中表面灰层内气体扩散传质特性的研究

煤在燃烧过程中表面灰层内气体扩散传质特性的研究严建华，倪明江，张宏焘，岑可法（浙江大学能源工程系杭州３１００２７）关键词：灰层扩散，煤燃烧，孔隙率一、引言就流化床燃烧锅炉通常燃用的较大粒度的煤而言，其焦碳的燃尽时间占了煤粒燃尽所需时间的绝大部分，粗略...