Fabrication and catalytic property of an Ag@poly(3,4-ethylenedioxythiophene) yolk/shell structure

Poly(3,4-ethylenedioxythiophene) (PEDOT) hollow spheres with the size ranged from 210 to 850 nm and a conductivity of 6 × 10^?2 S cm^?1 have been prepared via electrochemical polymerization of 3,4-ethylenedioxythiophene in the presence of poly(vinyl pyrrolidone) as a soft template. Then, a novel Ag@PEDOT yolk/shell structure has been prepared simply and directly by a penetration and reduction approach. The morphology, formation, and the catalytic activity of the as-prepared Ag@PEDOT yolk/shell structure have been investigated. The experimental result shows that the as-prepared Ag@PEDOT yolk/shell structure exhibits excellent catalytic activity on reduction of p-nitrophenol. The employed approach may shed some light on preparing other noble metal@conductive polymer core/shell structure.     

Polypyrrole nanofibers synthesized via reactive template approach and their NH3 gas sensitivity

The synthesis of polypyrrole (PPy) nanofibers has been achieved via a simple reactive template approach. The reactive template of FeCl₃ and methyl orange (MO) leads to the formation of uniform PPy nanofibers. Moreover, the fabrication of PPy nanofibers with high yield is realized, suggesting that this methodology is appropriate for the large-scale production of the corresponding nanomaterials. In contrast to the NH₃ gas sensor based on bulk PPy, the gas sensor based on the as-prepared PPy nanofibers exhibits greatly improved performances.     

Preparation and electrochemical performances of graphite oxide/polypyrrole composites

Graphite oxide/polypyrrole composites (GPys) were prepared by in situ polymerization and reduced by NaBH₄ to prepare reduced graphite oxide/polypyrrole composites (R-GPys). On the basis of the morphological and structural characterization of the composites by Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests, the electrochemical performances of the composites were investigated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance techniques. The experimental results showed that the specific capacitances of the composites before and after reduction (197 and 180 F/g) were highly improved compared with that of pristine graphite oxide (11 F/g) and polypyrrole (112 F/g), respectively. The capacitance retention of about 73% for R-GPys compared with 12% for PPy and 47% for GPys after 1200 cycles indicated the high cycle stability of the R-GPys and its potential as an electrode material for supercapacitor applications.     

High frequency complex permeability of flake-shaped Fe_(74)Cr_2Mo_2Sn_2P_(10)Si_4B_4C_2 particle composite material

A composite consisting of flake-shaped Fe74Cr2Mo2Sn2P10Si4B4C2 particles was prepared.The flake-shaped particles included in the composite were prepared by planetary ball milling.The complex permeability of the composite material was measured at frequency range from 10 MHz to 8.5 GHz.The permeability of the composite containing flake-shaped particles was much higher than that of the spherical particles.The permeability of particles was improved by means of heat-treatment.In contrast to the random-spatial-di...     

An approach for generating a tasks schedule model in web-based virtual manufacturing system of screw threads

In this paper, several web-based interfaces for user interaction and a task-oriented decision approach are proposed to build a tasks schedule model and then display the manufacturing process in a virtual environment, which is created by a geometric virtual-reality-based visualization technology for screw threads generation. The proposed tasks schedule model consists of four types of objects: virtual component, state manager, transfer operator, and flow controller. The virtual component has a geometric model with kinematics and their attributes. To control the geometric model, a component controller which models the logical aspects of a component is used. The component controller should be able to implement component-level orders by operating the geometric model. For the fidelity of the tasks schedule model, a transfer operator has a set of component-level command imitating the physical mechanism of a transfer. As a result, more accurate simulation results can be expected. The flow controller makes decisions on friable transfers based on decision parameters, which are maintained by the state manager. To have better structure and easier implementation, a virtual manufacturing platform can be modeled in a hierarchical and modular manner as an integrated system consisting of a product design suite, a web interface module, and a visualization module. Meanwhile, it provides a solution of learning of manufacturing sequences, cost effective, platform independent, and sharing visualized information over the internet for virtual manufacturing. Finally, the tasks schedule model has been implemented with an example in screw threads generation.     

石墨工件上钻孔的新方法

分析了常规石墨工件加工工艺的缺陷,提出了改进措施。采用新方法可提高生产率、节约成本、延长钻模使用寿命。     

Method and device of Rubber tire simulation ＆ vulcanization

近日,全国橡塑机械信息中心主任一行走访了内蒙古宏立达橡塑机械有限责任公司.董事长王绁宏先生介绍,公司前身是成立于1954年的呼和浩特橡塑机械总厂,近些年公司稳抓稳打、步步为营,逐步完善了公司的改制及各项业务,形成了国内挤出机生产规格最齐全、形式最多样、工控技术先进的有利局面,并将公司发展目标设计定为2015年挤入国内橡机行业综合实力前列。     

太阳能热水系统在广西农村住宅中的应用

从广西农村住宅和能源使用实际出发,介绍太阳能热水系统在农村住宅分户应用的流程、特点和经济性,并提出太阳能热水系统在农村推广应用的建议。     

结构加固技术在保护性历史建筑中的运用

结合工程实践,针对历史性保护建筑的结构现状,通过具体分析不同承重结构的特点和难点,制定了相应的不同加固方案,提高了建筑物的承载力和安全性。