船坞泵站泵装置模型优化试验研究

对船坞泵站泵装置进行了模型试验,讨论了水泵参数换算、试验结果及误差分析等问题,研究了导流方案与悬空高度对泵装置性能的影响．为提高泵装置性能,将原出水管道虹吸下降段及出口管径设计成渐扩管．试验结果表明,在悬空高度hp=0．76D0时,各种工况下进水流态平顺,流道内无涡带发生,水泵运行平稳,装置效率可提高0．5％-1．5％．     

Less Is More: Three‐Coordinate C,N‐Chelated Distannynes and Digermynes

We report here the synthesis of new C,N‐chelated chlorostannylenes and germylenes L³MCl (M=Sn( 1 ), Ge ( 2 )) and L⁴MCl (M=Sn( 3 ), Ge ( 4 )) containing sterically demanding C,N‐chelating ligands L^{3, 4} (L³=[2,4‐di‐tBu‐6‐(Et₂NCH₂)C₆H₂]^?_; L⁴=[2,4‐di‐tBu‐6‐{(C₆H₃‐2′,6′‐iPr₂)N=CH}C₆H₂]^?). Reductions of 1 – 4 yielded three‐coordinate C,N‐chelated distannynes and digermynes [L^{3, 4}M ]₂ for the first time ( 5 : L³, M=Sn, 6 : L³, M=Ge, 7 : L⁴, M=Sn, 8 : L⁴, M=Ge). For comparison, the four‐coordinate distannyne [L⁵Sn]₂ ( 10 ) stabilized by N,C,N‐chelate L⁵ (L⁵=[2,6‐{(C₆H₃‐2′,6′‐Me₂)N?CH}₂C₆H₃]^?) was prepared by the reduction of chlorostannylene L⁵SnCl ( 9 ). Hence, we highlight the role of donor‐driven stabilization of tetrynes. Compounds 1 – 10 were characterized by means of elemental analysis, NMR spectroscopy, and in the case of 1 , 2 , 5 – 7 , and 10 , also by single‐crystal X‐ray diffraction analysis. The bonding situation in either three‐ or four‐coordinate distannynes 5 , 7 , and 10 was evaluated by DFT calculations. DFT calculations were also used to compare the nature of the metal–metal bond in three‐coordinate C,N‐chelating distannyne [L³Sn]₂ ( 5 ) and related digermyme [L³Ge]₂ ( 6 ).     

基于GIS矢量数据结构的公交数据模型的实现

为了给乘坐公交出行的人们提供准确且有效率的最优乘车路线，在GIS矢量数据结构的基础之上，对公交数据的模型从其公交网空间位置以及关系网方面进行了分析和研究。对常用的公交规划软件的公交模型数据库进行分析，并对基于GIS矢量数据结构的公交数据模型空间数据采集方式进行了改进，以达到最小换乘次数和最小途经站数。该模型能够实现公交模型数据库的快速创建，且维护效率高，为我国公交网络系统模块的反馈机制提供了多种规划方案和技术支持。     

影响系统主因素综合筛选技术研究

系统影响因素过多不仅会增加系统建模难度,而且会增加系统模型的不确定性和数据收集工作量,因此提出一种影响系统的主因素综合筛选技术.技术将综合灰色关联度、普通相关技术、逐步回归方法、DEMATEL法以及系统动力学等方法的优点和缺点,通过彼此互补和相互融合技术,使得该技术能够有效地筛选出影响系统的主因素.通过在筛选影响船舶柴油机寿命周期费用主因素的应用,和其他方法的比较和分析,验证了本技术的可行性、有效性和先进性.     

课堂教学关系圆的构筑与实践

在分析课堂教学主要关系的基础上,结合环境类基础课程的课堂教学,兼顾知识内容、方法程序和应用探索等环节,探讨了提高课堂教学有效性的综合策略,提出了构筑课堂教学关系圆的理念,将课堂教学诸多关系构筑一个多边形,多边形的边越多,意味着课堂关系分析和处理得细致均衡,就会越接近圆形,也就越容易前行,越有利于促进师生共同发展和教育的进步。     

地方本科院校公共计算机教育改革的探讨

针对地方本科院校公共计算机教学中存在的问题,依据学生生源地域性和所学专业性的特点,从教材的选定到因材施教,进行教学改革。同时不断提高师资队伍素质,采用"双主型"教学模式,提高学生创新动手能力。总结了一条地方本科院校公共计算机教育可行的方案。     

Recent Advances in the Field of Main‐Group Mono‐ and Diatomic “Allotropes” Stabilised by Neutral Ligands

The study of ligand stabilised mono‐ and diatomic zero oxidation state complexes is a young and fascinating topic. This area merges the fields of low‐oxidation‐state main‐group chemistry, homoatomic multiple bonding and fundamental coordination chemistry. As with a great deal of recent coordination chemistry within the d‐block, carbene ligands are clearly the star of the show, highlighting their importance within the p‐block as well. This Minireview focuses on the significant developments of the past two years.     

Pluripotent Features of Doubly Thiophene-Fused Benzodiphospholes as Organic Functional Materials

Linear ladder-type π-conjugated molecules have attracted much interest because of their intriguing physicochemical properties. To modulate their electronic structures, an effective strategy is to incorporate main-group elements into ladder-type π-conjugated molecules. In line with this strategy, a variety of ladder-type π-conjugated molecules with main-group elements have been synthesized to explore their potential utility as organic functional materials. In this context, phosphole-based π-conjugated molecules are highly attractive, owing to their unique optical and electrochemical properties, which arise from the phosphorus atom. Herein, the synthesis and physicochemical properties of doubly thiophene-fused benzodiphospholes, as a new class of phosphole-based ladder-type π-conjugated molecule, are reported. Systematic investigations into the physicochemical properties of doubly thiophene-fused benzodiphospholes revealed their pluripotent features: intense near-infrared fluorescence, excellent two-photon absorption property, and remarkably high electron-transporting ability. This study demonstrates the potential utility of doubly thiophene-fused benzodiphospholes as organic functional materials for biological imaging, nonlinear optics, organic transistors, and organic photovoltaics.     

A partition checkpoint strategy based on data segment priority

A partition checkpoint strategy based on data segment priority is presented to meet the timing constraints of the data and the transaction in embedded real-time main memory database systems(ERTMMDBS) as well as to reduce the number of the transactions missing their deadlines and the recovery time.The partition checkpoint strategy takes into account the characteristics of the data and the transactions associated with it;moreover,it partitions the database according to the data segment priority and sets the corresponding checkpoint frequency to each partition for independent checkpoint operation.The simulation results show that the partition checkpoint strategy decreases the ratio of trans-actions missing their deadlines.     

任职教育教学模式运用中的教学主体呈现

深化任职教育教学改革，要在正确理解教学模式内涵的基础上，把握好教学主体呈现要素，增强课程教学设计能力，提高任职教育教学效果。