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.     

Pulsating Jet Impingement Heat Transfer Enhancement

This article presents results from a numerical study of pulsating jet impingement heat transfer. The motivation is to seek conditions offering a significant enhancement compared to steady flow impingement drying. The CFD software package FLUENT was used for simulating slot-type pulsating jet impingement flows with confinement. The parameter study included velocity amplitude ratio, mean jet velocity, and pulsation frequency. The distance from nozzle exit to surface was three times the hydraulic diameter of the nozzle. The Reynolds number based on the nozzle hydraulic diameter and jet temperature was 2,460 with a mean jet velocity of 30 m/s, which is the base case of the numerical experiments. Results showed that time-averaged surface heat transfer increased with increasing velocity amplitude for the same mean jet velocity. Large velocity amplitudes helped enhance heat transfer by two mechanisms: high jet velocity during the positive cycle and strong recirculating flows during the negative cycle. For the cases with different mean jet velocities but the same maximum velocity, time-averaged surface heat flux decreased with decreasing mean jet velocity. As for the effects of pulsation frequency, with high-velocity amplitude ratio, time-averaged surface heat fluxes were at the same level regardless of frequency. However, at low-velocity amplitude ratio, high frequency caused stronger recirculating flows resulting in greater heat transfer compared to the cases with a lower frequency.     

罗坡坝水电站泄水建筑物设计及试验研究

罗坡坝水电站拱坝设置有三个溢流表孔,中间孔高程低于两侧的孔,三个泄水孔设有差动式挑坎。通过模型试验表明,不发生危及岸坡稳定的泄流雾化问题,此外,适当控制泄流水舌射程可以减少坝下冲坑深度,消能效果良好。     

面向智能计算的记忆结构理论综述

本文从智能计算角度出发，对记忆的总体结构、信息表征及记忆模型等方面的理论作一综述。并在分析、比较了这些理论与ＡＩ中的相关理论差异的基础上，对面向智能计算的记忆理论研究方法与方向作了扼要讨论。     

威远构造与震旦系油气勘探

本文扼要地论述了威远构造从30年代到60年代震旦系最古老气藏发现的漫长历史,以及直到90年代初震旦系天然气勘探重新获得突破的曲折过程。这一历史过程,也是四川盆地复杂碳酸盐岩裂缝性气藏勘探的剪影。     

关系数据库在专家系统中的应用

在传统的专家系统中，对推理机工作过程的控制是程序实现的。本文介绍了一个用数据库技术引导推理过程的专家系统－精神分裂症诊断专家系统（ＥＳＳＤ）的推理控制策略。在这个专家系统中，作者将有关推理过程的控制信息用关系数据库技术进行存储和管理，达到了将控制策略数据化的目的。将数据库技术引入到专家系统的推进控制机制中可以使控制策略比较容易调整，且而可以大大压缩程序篇幅，显著提高系统运行效率，为专家系统的结构设     

MOS结构准静态测试中的异常C—V曲线

本文报导了MOS结构在准静态测试中的异常电容-电压曲线。讨论了它们产生的原因。     

带化学反应的膛口温度场方程分歧解

提出膛口系统是一种准耗散结构，并分析了符合耗散结构的条件，在分析分歧解线性稳定性的基础上，使用高维定态投影解定态分歧解，分歧解与实验结果吻合较好。     

光纤智能复合材料

对光纤型智能复合材料的工作原理，性能特点和应用前景作了介绍，并讨论了制造成型的技术问题。