BaZrO3 hollow nanostructure with Fe (III) doping for photocatalytic hydrogen evolution under visible light

Visible-light-responded BaZrO₃ hollow nanostructure with Fe (III) doping was prepared through facile solvothermal reaction using ethanediamine (EDA) as solvent. Fe doping in BaZrO₃ as an efficient way of reducing its wide band gap (～4.96 eV) is realized in order to achieve visible light response. The corresponding trapping center introduced by Fe³⁺ doping contributes to the lower recombination of photo-induced holes and electrons. Meanwhile, the special hollow structure with larger specific area is also a key factor to increase optical absorption, charge carrier migration rate and redox reaction sites. Hence, the participation of Fe and hollow nanostructure are responsible for the visible-light-driven photocatalytic hydrogen evolution.     

TiO2/CdS composite hollow spheres with controlled synthesis of platinum on the internal wall for the efficient hydrogen evolution

Solar driven semiconductor photocatalytic water splitting to produce hydrogen is an extremely charming process by storing photon energy in chemical bonds. In the present study, composite semiconductor TiO₂/CdS was structured into uniform and porous double-shelled hollow sphere with cocatalyst platinum selectively loaded onto the internal wall. The SEM, TEM, STEM, XRD, BET and EDS elemental distribution etc. were employed to evidence the formation of the targeted photocatalyst. It was demonstrated that the material has a high efficiency of visible-light-driven hydrogen evolution (296 μmol·h⁻¹/10 mg) with an apparent quantum efficiency (QE) of 14.5% at wavelength of 420 nm. Comparative experiment analysis and time-resolved infrared absorption study suggested that the high photocatalytic activity of the catalyst is attributed to the vectorial electron transfer (CdS → TiO₂ → Pt) and the spatial separation of reduction and oxidation active surfaces achieved by the special morphology.     

低密度BMC复合材料性能的研究

研究了四种不同种类的空心玻璃微珠的加入对团状模塑料(BMC)密度及性能的影响,观察空心玻璃微珠在BMC中的分散及破损情况以及空心玻璃微珠S38含量的变化对BMC密度及性能的影响。结果表明,随着微珠含量的增加密度及拉伸强度逐渐下降;微珠含量为5%时弯曲及冲击强度达到最大值。研究微珠的表面处理对BMC性能的影响,结果表明,微珠的表面处理能有效提高BMC的力学性能。     

Preparation of platinum-doped hollow spheres and their electrocatalytic activity in water electrolysis

Pure TiO₂ hollow spheres were prepared by using poly(styrene-methacrylic acid) latex particles as template; thereafter, titania hollow spheres were coated by platinum with an appropriate amount of choloroplatinic acid solution to obtain Pt/TiO₂ catalysts. The morphology and structure of nonstructural Pt/TiO₂ hollow spheres were characterized by BET, XRD, TGA, SEM and TEM analysis. In the samples, a remarkably uniform layer of Pt consisting of particles from 5 to 70 nm in size was formed over TiO₂ hollow spheres. We found the electrocatalytic nature of the samples by cyclic voltammetric experiment in acidic solution. The anodic peak current density of 20 wt% Pt-loaded TiO₂ hollow particles was observed 2.5 times higher than that of 5 wt% Pt/TiO₂ in the same experimental condition. Also, the anodic current density of 20 wt% Pt/TiO₂ hollow spheres calcined at various temperatures followed the order: 400 °C≈500 °C>600 °C. The electrocatalytic activity of the Pt-loaded TiO₂ hollow spheres depends on the amount of atomic platinum present in the sample; a higher concentration of platinum results in a larger current density value in anodic sweep, resulting in more oxygen production during electrolysis. Pt/TiO₂ hollow sphere catalysts have also shown long term electrocatalytic stability in acidic media.     

基于并行工程的中空吹塑模集成系统研究

针对采用传统的串行模式进行中空吹塑模具设计和制造中存在的问题,提出基于并行工程的中空吹塑模集成系统流程,使其贯穿于中空吹塑成型的共性机理研究、制品设计、模具设计与制造和试模的全过程,并讨论制品设计与模具CAD/CAE/CAM的并行设计、中空吹塑产品的特征建模、中空吹塑模CAD/CAE/CAM知识和规则处理机制等关键技术。     

芯板厚度对超塑成形的影响

根据超塑成形的工艺要求,利用ANSYS/LS-DYNA有限元软件对空心风扇叶片成形过程进行数值模拟分析,以此研究不同的芯板厚度对超塑成形结果的影响.分析的结果表明:选取的三种厚度的芯板里,当厚度为0.8mm时,塑性变形最均匀,成形效果最好.     

TC4合金空心可调叶片的钎焊工艺研究

某机压气机的空心可调节叶片组件是由钛合金材料TC4合金通过钎焊制成的,每个叶片都是由叶片主体和2个叶形板组成,叶片主体与叶形板之间采用钎焊连接。本文针对空心叶片组件的结构特点和使用要求开展了真空钎焊工艺研究,进行了钎料钎焊接头力学性能测试,同时,就钎焊热循环对TC4合金性能的影响、钎焊工艺路线程序、叶片焊后变形校正等工艺问题进行了深入研究,所确定的真空钎焊工艺程序可以钎焊出合格的可调叶片组件,钎焊质量稳定。     

局部加载下中空夹层钢管混凝土的试验研究

对局部受压下的中空夹层钢管混凝土进行试验研究。分别对含内外两层钢管的14个圆形构件和15个方形试件进行试验,试验参数包含:空心率、顶端板厚度、局压面积比。结果表明:局部受压下中空夹层钢管混凝土呈现延性。各试验参数对局部受压中空夹层钢管混凝土短柱的性能和破坏模型有很大影响。最后,提出分析局部受压下中空夹层钢管混凝土承载力的简化计算模型。     

无帽口钢锭的推广应用

分析了常规钢锭与无帽口钢锭制作筒类锻件的特点。明确指出无帽口钢锭锻件的优势:提高了钢锭利用率和锻件合格率,有效降低了冶炼和锻造成本,生产效率显著提高。     

空心结构ZnSn(OH)6立方体制备及其可见光催化性能研究

以乙酸锌、锡酸钠、氟化铵为原料,利用NH₄F刻蚀,采用水热法制备了尺寸250 nm的空心结构ZnSn(OH)₆立方体,通过X射线衍射(XRD)、红外光谱(FTIR)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)、荧光光谱(PL)等来表征ZnSn(OH)₆的晶体结构、形貌和光学性能,研究水热时间对ZnSn(OH)₆形貌的影响,通过降解亚甲基蓝(MB)来探索不同形貌的ZnSn(OH)₆的光催化性能。结果表明,水热2 h制备的ZnSn(OH)₆具有完整的空心结构,且对亚甲基蓝(MB)在可见光下降解效率最优,在降解过程中·O^2-起主要作用,其稳定性良好。说明空心ZnSn(OH)₆立方体光催化材料是一种具有广阔应用前景的可见光催化降解材料。