液晶中间体对溴正戊苯的合成

以溴苯、正戊酰氯和水合肼为原料 ,经Friedel Crafts酰基化反应和Wolff Kishn er 黄鸣龙还原反应合成对溴正戊苯。研究表明 ,酰基化反应较佳的条件是 ,n(正戊酰氯 )∶n(溴苯 )∶n(三氯化铝 ) =1∶2∶1 4,反应温度 30～ 35℃ ,反应时间 5h ;还原反应较佳的条件是 :n(对溴苯戊酮 )∶n(水合肼 )∶n(氢氧化钾 ) =1∶1 1∶0 2 ,反应温度 1 80～ 1 90℃ ,反应时间 3h。产品总产率约为 40 % ,纯度为 99 3%     

沟槽面在湍流减阻中的应用

对近些年来的沟槽面湍流减阻技术的工业应用方向 ,沟槽的几何形状和尺度、流场压力梯度、沟槽面放置方式对于沟槽减阻效能的影响 ,沟槽面对于湍流边界层流动特性的影响 ,沟槽面的湍流减阻机理几方面研究进展进行了综述。从湍流拟序结构理论出发提出 :具有减阻效应的沟槽面不但能通过控制低速制条带间距来降低湍流“猝发”频率 ,而且在“猝发”后的高速“下扫”过程中因其几何结构使藏在槽内的安静流体避免或部分避免因高速“下扫”而“诱导”出较大速度剪切层 ,从而实现减阻。同时指出需要利用先进的实验技术如PIV等图像处理手段并结合直接数值模拟对湍流边界层的瞬时流场进行研究 ,以其找出湍流边界层的流动结构及其运动规律。     

合金化提高铂在PEMFC氧还原反应中的催化活性

用液相沉积-高温合金化法制备了铂基合金催化剂,用能量散射光谱(EDS)、X射线衍射(XRD)技术对催化剂的结构进行了研究,并测试了使用此催化剂的质子交换膜燃料电池(PEMFC)性能,结果表明铂基合金具有面心立方的结构,铂与过渡金属的原子比接近3∶1;制备的催化剂性能优越,具有比纯铂更强的电催化能力,催化剂活性由高到低的顺序是Pt-Cr/C→Pt-Co/C→Pt-Ni/C→Pt/C。讨论了合金元素对催化剂活性的强化作用,认为合金元素的引入减小了Pt-Pt原子间距,降低了Pt的d电子轨道占有率,提高了催化剂的性能。     

高层悬挂结构体系的减震研究

论述了高层悬挂结构体系利用悬挂楼层减小结构地震反应的原理及其减震性能，给出了体系的力学模型和振动方程．通过具体算例，利用数值分析方法对结构体系进行时程分析，探讨了在保持结构楼层总质量不变的情况下，悬挂楼层的质量大小对结构减震效果的影响．计算结果表明，减震效果随悬挂质量的增加而增加，但当悬挂质量占结构总质量的2／3以上时，减震效果增加缓慢．悬挂质量的大小应根据工程的实际情况而定．为获得最佳的减震效果，建议悬挂部分的质量取结构总质量的1／2—2／3。     

回顾与展望再创节能降耗新水平

回顾了“九五”以来武钢节能降耗所取得的成效及基本经验，通过与宝钢能耗指标的对照剖析，找到节能潜力和有效途径，展望“十五”，持续发展，创节能降耗新水平。     

Control of Variation by Reward Probability.

Two bar-press experiments with rats tested the rule that reducing expectation of reward increases the variation from which reward selects. Experiment 1 used a discrete-trial random-interval schedule, with trials signaled by light or sound. One signal always ended with reward; the other signal ended with reward less often. The 2 signals were randomly mixed. Bar-press duration (how long the bar was held down) varied more during the signal with the lower probability of reward. Experiment 2 closely resembled Experiment 1 but used a random-ratio schedule rather than a random-interval schedule. Again, bar-press duration varied more during the signal with the lower probability of reward. The results support the rule--the first well-controlled comparisons to do so. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Study of the Effect of Aluminium on the Mechanochemical Reduction of Hematite by Graphite

The effect of addition of small amounts of aluminium on mechano‐chemical reduction of hematite by graphite was studied. Various amounts of aluminium (0 to 10%) were added to a hematite‐graphite mixture, in which C/O ratio was 1:1. The hematite‐graphite‐aluminium mixtures were then subjected to ball milling followed by heating up reduction. The heating up reduction was carried out in Ar atmosphere, using TG‐DTA device. In TG‐DTA experiments, samples were heated by a constant heating rate of 10 °C/min from room temperature up to 1100 °C and maintained for 30 minutes at this temperature. To clarify the reactions which took place during milling and heating up reduction, the samples were subjected to XRD examinations. It was found that the heat generated during exothermic reaction of aluminothermic reduction of hematite promoted the endothermic reaction of carbothermic reduction. In the course of heating up reduction, the carbothermic reaction occurred just after aluminothermic reaction. Increasing of aluminum content from 0 to 10% in 2 hours ball milled samples decreased the temperature of carbothermic reaction from 1020 °C to about 860 °C. The further ball milling of the samples up to 5 and 10 hours, for the samples containing 10 and 5% aluminium respectively, caused the decrease of the temperature of aluminothermic and carbothermic reactions to around the melting point of aluminium.     

基于粗糙集理论的分层递阶约简算法􀀂

粗糙集理论的分层递阶约简算法是根据属性的获取方式、采集成本和实时性要求等对属性进行分类,使信息系统或者决策系统中的所有属性在单层次和单粒度上的知识表示变为部分属性所构成的知识在多种层次和多种粒度上的表示,从而可以逐层对信息系统进行约简.分层递阶约简算法在某水泥窑炉控制决策获取中的应用证实其有效性.     

Influence of V2O5 Addition on Reduction of NO by C3H6 over Pt/V2O5/Al2O3 Monolithic Catalyst

Pt/V2O5/Al2O3 and Pt/Al2O3 monolithic catalysts were prepared by wet impregnation method, and the influence of V2 O5 addition on the catalytic activity for NO reduction by C3 H6 under lean burn condition was investigated in detail.The results show that Pt/V2O5/Al2O3 has better activity of NO reduction than Pt/Al2O3 , adding V2O5 to Pt catalyst makes the temperature window of NO reduction shift further to a lower temperature region.The activity of NO reduction decreases and there is a similar degree of deactivation over the two catalysts in the presence of SO2 in feed gas.Moreover, adding V2 O5 to Pt catalyst resulted in improvement of resistance to SO2 oxidation, which decreases the emission of sulfate particulate.Thermal aging treatment counteractes the promoting effect of V2O5 on NO reduction.     

基于变精度容差粗集的鲁棒分类器

该文基于目标识别中出现的不确定问题,提出了一种改进的粗集模型:变精度容差粗集模型。利用粗集中信息容量的定义,对不确定系统进行属性约减,并利用约减后的结果进行目标识别,仿真试验表明,利用该粗集模型进行目标识别时,具有较高的识别率和较高的鲁棒性。