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所属行业:化学原料和化学制品制造业

  • 21791.氧化锌纳米线:合成方法和电学性能

    [电气机械和器材制造业,化学原料和化学制品制造业] [2015-09-02]

    In the present chapter we aim to overview the synthesis techniques and growth mechanism of zinc oxide (ZnO) nanowires and their related properties. In particular, here we review both wet and dry synthesis techniques reported in the literature, such as hydrothermal and sol-gel routes, template-assisted growth, electrodeposition process, chemical vapor deposition (CVD), pulsed laser deposition and RF magnetron sputtering. According to each synthesis technique, the chapter reports not only the detailed procedure, but also the advantages and disadvantages, analyzing in particular the properties of ZnO nanowires related to their microstructural and morphological features. The functional properties of ZnO nanostructures are also overviewed with a particular attention to their electrical properties and the related potential applications, exploiting either the semiconductive and piezoelectric behavior of ZnO nanowires. A comprehensive review is here focused on their use as field effect transistor, energy nanogenerators, pH and gas sensors, as well as the use of ZnO nanowires for energy conversion, like photovoltaic cells and water splitting photoelectrochemical cells.
    关键词:电池材料;电解质材料;电学性能
  • 21792.二氧化钛纳米颗粒和纳米结构的光催化应用

    [科学研究和技术服务业,化学原料和化学制品制造业,电气机械和器材制造业] [2015-09-02]

    Titanium dioxide (TiO_2) is the most intensely investigated photocatalyst and until today the only one that has already been commercialized and that is involved in many applications such as self-cleaning materials, dye-sensitized solar cells, as well as water and air purification. Consequently, an exponential growth of research activities concerning the nanoscience and nanotechnology of TiO_2 has been observed during the last decades. These raising research activities have recently lead to the synthesis of nanosized TiO_2 nanoparticles and nanostructures with different shapes, morphologies and phase compositions. Thus, the present chapter focuses mainly on the synthesis of these nanomaterials. The thermodynamic stability, the transition between different TiO_2 polymorphs and the surface properties of these polymorphs are presented with the aim to utilize this information for a better understanding of the mechanism of the formation of TiO_2 nanomaterials. The photocatalytic applications of these TiO_2 nanomaterials are also discussed.
    关键词:电池材料;光催化剂;纳米材料
  • 21793.平面固态氧化物燃料电池的研究和开发

    [化学原料和化学制品制造业,电气机械和器材制造业] [2015-09-02]

    Numerical simulation capabilities to perform flowfield analysis and sensitivity analysis of solid oxide fuel cells (SOFCs) have been developed. A three-dimensional, implicit, multi-species fuel cell solver is modified to analyze cell geometries supplied by NexTech Materials (NexTech). Four different NexTech cell configurations of varying complexities have been analyzed in this study. A capability to perform thermo-mechanical analysis of NexTech cells is developed by coupling the fuel cell code with the structures code. The capability was initially developed for a simplified cell that also included sensitivity analysis of thermo-mechanical variables. Sensitivity derivatives are computed using the direct differentiation method in the fuel cell and structures codes.
    关键词:燃料电池;氧化物;平面结构
  • 21794.碱性阴离子交换膜的碳酸盐、碳酸氢盐离子运输

    [化学原料和化学制品制造业] [2015-09-02]

    The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggesstions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA, 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any oenalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
    关键词:碱性阴离子交换膜;阴离子交换;燃料电池系统
  • 21795.燃料电池技术的单原子铂催化剂非传统角色:理论表面科学的方法

    [电力、热力、燃气及水生产和供应业,化学原料和化学制品制造业] [2015-09-02]

    As a first step towards a microscopic understanding of single-Pt atom-dispersed catalysts on non-conventional TiN supports, we present density- functional theory (DFT) calculations to investigate the adsorption properties of Pt atoms on the pristine TiN(100) surface, as well as the dominant influence of surface defects on the thermodynamic stability of platinized TiN. Optimized atomic geometries, energetics, and analysis of the electronic structure of the Pt/TiN system are reported for various surface coverages of Pt. We find that atomic Pt does not bind preferably to the clean TiN surface, but under typical PEM fuel cell operating conditions, i.e. strongly oxidizing conditions, TiN surface vacancies play a crucial role in anchoring the Pt atom for its catalytic function. Whilst considering the energetic stability of the Pt/TiN structures under varying N conditions, embedding Pt at the surface N-vacancy site is found to be the most favorable under N-lean conditions. Thus, the system of embedding Pt at the surface N-vacancy site on TiN(100) surface could be a promising catalyst for PEM fuel cells.
    关键词:燃料电池;原子吸附;计算缺陷
  • 21796.聚醚醚酮(PEEK)的移植聚合物电解质膜类型:燃料电池应用的相对湿度依赖

    [电气机械和器材制造业,化学原料和化学制品制造业] [2015-09-02]

    A pre-irradiation grafting method is a fascinating technique for direct introduction of new functional graft polymers (grafts) into polymer substrates without any damages. The radiation technique has been widely applied to the preparation of high performance fuel cell polymer electrolyte membranes (PEMs) for mobile electricities, vehicles, and domestic co-generation systems. The PEMs of aromatic hydrocarbon polymers, so-called "super engineering plastics" including poly (ether ether ketone) (PEEK), have useful characteristics such as high mechanical strength, gas barrier property, and radiation resistance. Thus, in this work, we investigated the humidity dependence of proton conductivity and mechanical strength at 80 ℃ and relative humidity (RH) from 30 to 95%, which are the most important characteristics for power generation efficiency and durability under real operating conditions in fuel cell systems.
    关键词:燃料电池;电解质材料;聚合物
  • 21797.聚电解质:科学和应用

    [电力、热力、燃气及水生产和供应业,化学原料和化学制品制造业] [2015-09-02]

    Polyelectrolytes, which are a macromolecule dissolved in water or polar solvent, have gained a wide attention among scientists and engineers for their wide application areas. Their different properties have allowed them to be used in many areas such as soap, body lotions, electrochromic devices, solid-state reference electrode systems, fuel cell exchange membranes, water treatment, waste treatment, paper production, corrosion protection, fuel cells, electrodialysis, contact lenses, membrane-based separations, drug delivery, and genetic science. Biocompatible polyelectrolytes are also utilized in biosensors and biomolecular recognition systems. Layer-by-layer (LbL) technique can be used to produce polyelectrolyte multilayer. Severe substrate such as gold, quartz, silicon, glass, plastic, stainless steel can be used in LbL technique. LbL technique is reproducible, cost-effective, and environmentally-friendly method. The characteristic properties of polyelectrolyte depend on the interaction between electrostatic forces. The degree of polymer charge can modify the electrostatic interactions. We examine the scaling theory according to Gennes et al. and Beurle and Nogovitsin in this chapter. After having discussed the scaling theory, we provide a basic introduction to properties of the neutron scattering and dynamic light scattering. In the end, we analyzed biopolymers and ionomers briefly. Polyelectrolytes (PEs) are generally denned as macromolecules, which when dissolved in water, dissociate to give highly charged polymeric molecules. As another definition, polyelectrolytes are polymers carrying either positively or negatively charged ionizable groups. These groups dissociate under appropriate conditions, and leaving ions on the chain and counter ions in the solution Examples of polyelectrolytes include polystyrene sulfonate, polyacrylic and polymethacrylic acids and their salts. DNA, proteins, nucleic acids, polysaccha-rides and other poly acids are given example to the natural polyelectrolytes. Polyelectrolytes are well known to play a vital role in nature and technology. PEs finds widespread use as solubilizing agents, phase separation agents, and rheo-logical property modifiers in daily life and technological applications. However, despite of their fundamental and practice importance, PEs systems still remain only poorly understood. This relates to the fact that their chemistry and physics are influenced by many controlling parameters, such as molecular weight, salt concentration, pH of the solution, etc.
    关键词:电池磁极;聚电解质;化学反应
  • 21798.化学氢生成和操作设备存储的原型系统

    [电气机械和器材制造业,化学原料和化学制品制造业] [2015-09-02]

    This research project sought to develop a prototype hydrogen-based fuel cell system for ITS devices. The project investigated hydrogen storage capacities of the various candidate chemical hydride analogs; selected the most efficient of the candidates for energy storage based on volume, mass, and cost; developed a prototype system; and estimated the capital and operating cost for such a system. A hydrogen fuel cell combines hydrogen and oxygen to produce electricity, providing a clean, high-efficiency energy source that circumvents the problems associated with conventional batteries. A major drawback that limits its utility, however, is the use of heavy and bulky compressed metal cylinders as the source of hydrogen. The chemical-based hydrogen generation used in this project can provide a compact, atmospheric-pressure storage option for the controlled release of hydrogen. Many ITS-based applications can be envisaged with hydrogen-based fuel cells, such as alternating-traffic signs, directional signals, speed-limit signs, blinkers in series, warning blinkers, and backup power sources at traffic signals during power outages. This system is particularly attractive because many remote traffic signals on northern Minnesota roads lack access to a power grid, requiring the use of batteries that must be changed often, thus incurring maintenance costs.
    关键词:电动电池;燃料电池;智能交通系统(ITS)
  • 21799.来源于氯化聚(丙烯)胺化与支链聚(乙烯亚胺)的碱性阴离子交换膜的制备和表征

    [化学原料和化学制品制造业,电气机械和器材制造业] [2015-09-02]

    A new randomly crosslinked polymer is investigated for use as an ion- exchange membrane. The polymer was produced through amination of chlorinated poly(propylene) (PP) with poly(ethyleneimine) (PEI) and quaternized with iodoethane. The synthesis of the new polymer is confirmed by FTIR 1H and 13C NMR. The microstructure of the polymer consists of aggregates on the order of 1 micrometer. Environmentally controlled small and wide angle X-ray analysis showed a relatively featureless amorphous morphology over length scales less than 105 nm through a full range of humidity environments. Little physical swelling of the films were observed, but very high internal water uptake was observed with lamba = 50. The highest in-plane ionic conductivity with chloride as the counter ion observed was 0.29 mS cm 1 at 90 deg C and 95% relative humidity. Infrared spectroscopy was used to monitor the relatively rapid rate of counter-ion reaction of hydroxide with ambient CO2 to form a mixture of carbonate and bicarbonate when exposed to air.
    关键词:离子交换;膜;聚合物;碳酸氢盐;氯化物
  • 21800.二次锂金属电池离子液体电解质的溶解气体的作用

    [电气机械和器材制造业,化学原料和化学制品制造业] [2015-09-02]

    The effect of dissolved gas on the reversibility of a Li/Li+ electrode in an ionic liquid electrolyte was investigated. Lithium metal is a potential anode in lithium batteries. The ionic liquid electrolyte was saturated with argon, nitrogen, oxygen, air.
    关键词:锂电池;液体电解质;二次电池
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