Syntheses and Structural Characterization of Triorganotin Derivatives of Bis(carboxymethyl)trithiocarbonate: X-ray Crystal Structures of 2D Network Polymers

Six triorganotin(IV) complexes of the type {(R₃Sn)₂[C₃S₃(COO)₂]}_n (R = C₆H₅ 1; n-Bu 2; PhCH₂ 4; p-F-PhCH₂ 5; o-F-PhCH₂ 6) and {(R₃Sn)₂[C₃S₃(COO)₂]}_n·[EtOH] (R = Me 3) have been synthesized by the reaction of bis(carboxymethyl)trithiocarbonate with triorganotin(IV) chloride in the presence of sodium ethoxide. All complexes were characterized by elemental analysis IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy. Except for 4–6, all complexes were also characterized by X-ray crystallography. The X-ray date revealed that complexes 1–3 show two-dimensional network polymeric structure in which the geometries of tin atoms are trigonal bipyramid with the axial positions occupied by carboxylic oxygen atoms.     

Hydrothermal Synthesis of Magnesium Aluminate Platelets

Magnesium aluminate (MgAl₂O₄) platelets were first synthesized by hydrothermal treatment of γ-AlO(OH) in a magnesium nitrate aqueous solution at 400°C. The platelets are 100–200 nm in width and 25 nm in thickness. The influence of temperature, the anions of the magnesium salt, the amount of magnesium salt, and precursor pH on the formation of such structure was investigated. The experimental results indicated that the anions of the magnesium salt and precursor pH could have a significant influence on the growth of MgAl₂O₄. MgAl₂O₄ formation followed the in situ transformation mechanism, which was the reason why the MgAl₂O₄ crystallites had a platelet morphology.     

基于MapInfo的西气东输管线地理信息系统的研究

讨论了西气东输管线空间数据库的建立过程，并以该空间数据库为后台利用MapInfo公司的GIS组件MapX进行二次开发，实现了全数字化的输气管道信息的存储与查询，使输气管线信息化管理更加现代化。     

灌区参与式管理存在的问题与对策

参与式灌溉管理是我国正在推广应用的灌区管理模式，本文通过对我国目前已实行参与式灌溉管理灌区的运行情况的调查，简单阐述了这种管理模式的绩效，着重分析了管理运行过程中存在的问题，并提出了解决这些问题的措施和建议。     

LonWorks总线在锅炉模糊控制系统中的应用

采用LonWorks总线技术可以提高锅炉控制系统燃烧效率及可靠性、保证环保要求、降低成本、优化网络的热量分配。尤其多台锅炉通过LON总线联网运行能够合理分配负荷,从而达到提高工作效率的目的。     

七里河市区段河道整治工程规划设计的实践与思考

我国有不少城市有河流穿过，市区段河道整治工程有防洪和美化城市双重功能，鉴于朔州市七里河河道整治工程的实践，笔者认为，市区段河道整治工程规划必须与城市总体规划布局相适应，工程设计在坚固耐用的同时应突出美观新颖，如果兴建水库，应在河道上游设置报汛机构，确保水库正常运行，还可以发挥市区土地价格高的优势，裁弯取直，回填土方，新增土地，筹措建设资金，体现以人为本、可持续发展、构建和谐社会的水利建设要求，将影响市容市貌的弯曲扭折的河道，变为城市中一道亮丽的风景线。     

排气管偏置对PV型旋风分离器性能影响的研究

以Ф300mm、标准PV型旋风分离器为基准模型进行冷态对比实验，研究了排气管与筒体轴线偏心布置对PV型旋风分离器分离性能的影响。结果表明，排气管偏置是进一步提高PV型旋风分离器性能的有效措施之一。在适当的偏心矩和偏置方位下，不仅能降低压降，还可以显著提高分离效率。     

GPS定位精度的提高及其应用

本文简明介绍了美国全球定位系统(GPS)的工作原理和误差来源,通过了解误差来源阐述了较准准确的定位技术DGPS的原理和应用。     

有关地下公共娱乐场所防排烟设计的探讨

根据地下公共娱乐场所的结构特点和火灾特点,结合某地下娱乐场所的防排烟设计,探讨如何进行防排烟设计。