Enhanced photocatalytic properties of N–P co-doped TiO<Subscript>2</Subscript> nanosheets with {001} facets

Nitrogen (N) and phosphorus (P) co-doped anatase TiO₂ nanosheets were realized by low-temperature self-doping N–TiO₂ followed by high-temperature P doping with foreign precursor. It is found that P doping process can maintain good TiO₂ nanosheets morphology with exposed {001} facets. Chemical state of dopants indicates that N and P atoms replace O on O sites in TiO₂ lattice. Compared with pure TiO₂ and N-doped TiO₂, N–P co-doped TiO₂ nanosheets exhibits stronger optical absorption and higher degradation rate of dye molecules in visible light regime. The enhanced photocatalytic properties are attributed to two factors. On one hand, N–P co-doping can effectively reduce band gap of TiO₂ from 3.20 to 2.48 eV, leading to an enhancement of the absorption in visible light regime. On the other hand, the presence of exposed {001} facets of TiO₂ nanosheets can induce the effective separation of photogenerated electrons and holes in reaction.     

集输管道绝缘接头强度评价方法研究

绝缘接头作为阴极保护系统的关键组件,其安全性与可靠性的研究在不断深入。由于集输系统高温、高压的特点,绝缘接头必然承受由于内压和热胀等导致的弯矩,加之其结构特点,可能会引起泄漏。为此,有必要综合考虑工况条件,研究绝缘接头可承受的安全弯矩值,并形成基于强度的评价方法。根据规范要求,结合管道强度理论,推导了绝缘接头承受弯矩范围的计算公式,提出了对应的绝缘接头强度校核与设计弯矩值选取方法;研究成果为绝缘接头安全设计与强度校核提供了参考与借鉴。     

Forecasting complex group behavior via multiple plan recognition

Group behavior forecasting is an emergent research and application field in social computing. Most of the existing group behavior forecasting methods have heavily relied on structured data which is usually hard to obtain. To ease the heavy reliance on structured data, in this paper, we propose a computational approach based on the recognition of multiple plans/intentions underlying group behavior.We further conduct human experiment to empirically evaluate the effectiveness of our proposed approach.     

The geochemistry of trace elements in marine oil shales and their combustion residues: Occurrence and environmental aspects

With the aim of better understanding geochemistry of trace elements in marine oil shale and its combustion residues, 23 raw samples, 17 oil shale combustion residues, and 18 selected minerals from Bilong Co oil shale are studied. Potentially hazardous trace elements in raw samples include As, B, Cd, Mo, and Se, while Se, Mo, Cd, As, Bi, and U are potentially hazardous trace elements in combustion residues. As is controlled mainly by Fe-bearing minerals. B occurs mainly in clay minerals. Cd is enriched mainly in calcite. Mo is controlled mainly by organic matter. Se is mainly controlled by P-bearing minerals.     

制备工艺对钯粉粒径的影响

探讨了利用液相还原法,以水合肼为还原剂,制备大颗粒钯粉,应用单变量对比试验的方法讨论了Pd2+浓度、温度、pH值对钯颗粒形核和生长过程的影响,这些因素的影响决定了钯颗粒粒度大小和服役性能。经分析和讨论,得出参数Pd2+浓度为0.1 mol·L-1,pH值为12,温度为50℃是最佳工艺参数的结论,并在此参数下制备出较大粒径的钯粉,且利用SEM,XRD,马尔文激光粒度仪、氮吸附等对其进行表面微观形貌、成分、粒度分布和比表面积等性能进行了分析,较有力地说明这种钯粉具有纯度高、比表面积大等优点,能够满足现排代服役条件的要求,对实际工业生产具有一定的指导意义。     

Electric field analysis of spinneret design for multihole electrospinning system

Electric field plays a key role in producing required nanofibers in electrospinning. This study aims to improve the electric field distribution of the multijet spinning system by designing the spinneret configuration. A novel 19-hole multistep electrospinning configuration is presented. The simulation results show that the electric field strength at the central position is intensified due to the protuberant step on the spinneret, and therefore more uniform electric field is obtained compared with the 19-hole flat spinneret. We demonstrate that the multistep spinneret configuration produces finer fibers and more continuous fiber mats compared with the flat spinneret configuration because of the improved electric field distribution. Jet repulsion in the multijet electrospinning process is studied. It is found that the electric field line distribution, which is determined by the spinneret configuration, plays a dominant role in influencing jet repulsion. Applied voltage is the main factor responsible for jet repulsion for a given spinneret configuration.     

亚硝基异戊酯催化的环境友好氧化脱肟反应

亚硝基异戊酯在分子氧存在下,可以有效的催化醛肟和酮肟为相应的醛和酮。结果表明催化体系的溶剂效应和苯环的取代基电子效应对反应影响很大。芳香酮肟可实现完全转化,醛肟和脂肪族肟也能获得良好的产率,所用催化体系反应条件温和,清洁高效。     

Two-step continuous synthesis of tetraethylthiuram disulfide in microstructured reactors

We present two-step continuous synthesis of tetraethyl thiuram disulfide using microstructured reactors, starting with the formation of N, N-diethyldithiocarbamic acid from carbon disulfide and diethylamine in the first mi- crostructured reactor, and the oxidation of N, N-diethyldithiocarbamic acid by hydrogen peroxide in the second one. We studied the effects of reaction temperature, LHSV and total flow rate on the yield of the product. In the first microstructured reactor assembled with an HPIMM micromixer and a stainless steel capillary as the delay loop, the yield of N, N-diethyldithiocarbamic acid reached 96.3% in the 40 wt% diethylamine ethanol solution under reaction conditions of the CS₂/(C₂H₅)₂NH molar ratio of 1.1: 1, total flow rate of 4 mL/min, LHSV of 42.4 h⁻¹, and reaction temperature of 25 °C. Consequently, the obtained N, N-diethyldithiocarbamic acid solution was reacted with H₂O₂ solution in another microstructured reactor assembled with SIMM-V2 and a PTFE capillary as the delay loop, the yield of the high purity tetraethylthiuram disulfide reached 89.3% under the optimized reaction conditions.     

如何做好屋面防水工程施工质量的控制

要想做好屋面防水工程施工，在进行屋面防水工程施工时应严格按照国家规定的要求进行，采用符合标准的防水材料进行。若在设计、建设和维护的任何一个环节中出现漏洞，那么屋面防水工程施工质量也会受到影响。     

《爱丽丝梦游仙境》制作技术与技巧探讨

《爱丽丝梦游仙境》采用了多种拍摄和制作技术,并且这些技术与技巧结合得非常好,给观众带来了一场非常完美的视听盛宴。本文主要介绍该片制作方案的确定、摄影器材的选择、为合成所作的准备、绿幕前拍摄和布光技巧、形象化预审视以及前后期如何完美结合实现2D转3D等制作技术与技巧等,并简要探讨现代电影制作中摄影师的职责和变化。