Effects of nanosized metallic palladium loading and calcination on characteristics of composite silica

1　INTRODUCTIONThemotivationfortheresearchoncolloidalmet alparticlesstemmedfromtheiruniqueelectro opticalandelectrochemicalproperties[13] .Duringthe pastfew years,aflurryofactivityhasbeendirectedto wardsthepreparationofnanosizedmetallicparticlesduetolargeenhancementinthephysicalpropertiesofnanostructuredcompositescomparedtothebulk[4 6 ] .Therefore ,size dependentchangesinband gapener gy ,excited stateelectronicbehaviorandopticalspec traaregenerateddrasticallyfromthoseknownforthemolecularan…     

基于双启发动态规划的预分解窑控制器设计

针对水泥预分解窑熟料煅烧过程多变量、多扰动、非线性,难以建立精确的数学模型,实际生产中对工人的生产经验依赖性较强等问题,提出采用误差反向传播(BP)神经网络建立烧成系统数学模型,设计预分解窑双启发动态规划(DHP)控制器。DHP评价网络输出代价函数J关于状态量的偏导数,获得最优或者次优的控制信号,然后由动作网络输出控制信号,使系统得到期望的控制轨迹。仿真结果表明控制器响应时间较快,各参量超调量均不大,有助于实际系统的稳定运行。     

Mg-Al-Eu三元层状化合物的结构和荧光记忆效应

研究了Mg-Al-Eu三元层状氢氧化物（TLH）分别在无CO2的去离子纯水（pH=7）、苯丙氨酸水溶液（pH=5）以及苯丙氨酸钠水溶液（pH =8,9,11）体系中的结构和荧光记忆效应.X射线衍射（XRD）测试结果发现：400℃煅烧后的TLH在这不同的体系中都能很好地重构成原始的TLH结构.荧光光谱（FL）研究结果表明：400℃煅烧后的TLH在一定时间内也能较好地恢复其原始的荧光性质;但超过一定时间后,其荧光性质将发生变化,这种荧光的变化可能与其重构产物在不同溶液体系中的浸泡时间和体系的pH有关;此外,还发现重构产物的结晶度和粒子尺寸与溶液体系的pH以及浸泡时间有关.     

煅烧煤矸石的火山灰活性

经ＸＲＤ证实永城煤矸石是砂质泥岩。其主要粘土矿物是高岭石，但加热相变有别于纯净的高岭石。当煅烧温度９００℃，活性来自偏高岭石的生成。当煅烧温度约１１００℃，生成相当数量的莫来石的同时存在较多的玻璃体，以致也具有良好的活性。     

炭素煅烧自动控制系统的设计与实现

针对目前回转窑炭素煅烧存在的工况不稳定和石油焦回收率低等问题,在分析了煅烧工艺中煅烧温度场对煅后焦质量的影响后,分别对温度场影响最大的给料量和窑尾负压进行了恒料恒压控制系统的设计。该系统利用自校正控制技术和PID技术分别实现了给料量和负压的恒定,同时根据现场需要完成了煅烧过程重要参数的监视、故障的在线诊断和控制方式间无扰切换等功能。实际运行表明系统可靠性高,实用性好。     

Calcination of Slags for Electroslag Remelting

The hydrides in industrial lime,alumina,magnesia,and calcium fluoride were investigated through differential thermal analysis and X-ray diffraction,and their mass losses during heating up were studied by thermogravimetric analysis method.The results indicate that the industrial alumina,lime,and magnesia,which have more moisture or hydride and mainly include γ-Al2O3,Ca(OH)2,and Mg(OH)2,lose more mass during thermogravimetric analysis process.However,the mass of premelted slag consisting of lime,fluorite,alum...     

Effects of Technical Conditions on Structure, Morphology and Crystalline Size of Nanocrystalline Nd-Doped Ceria Powders

Nanocrystalline solid solution CeO2-Nd2O3 powders were prepared by low temperature combustion process.Special attention was paid to the influence of the glycine/metal ratio and calcination temperature on the powders phase structure, morphology and particle size.TG-DSC curves and XRD peaks of different glycine/metal ratio show that smaller particle size can be obtained with a slightly fuel-deficient ratio.XRD results indicate that the as-prepared powders are crystallized in a single fluorite structure.The crystalline size ranges from 9 to 24 nm, which increases with the increase of calcination temperature.The lower SEM images were characterized by the spongy and form-like microstructure of the powders.Organic agent may be gradually eliminated by high temperature calcination process.     

煅烧条件对模拟高放废液煅烧产物物理化学性质的影响

模拟高放废液在回转煅烧过程中容易粘壁,影响其及时输送。为了实现转形工艺和固化工艺的顺利衔接,需要通过改变工艺条件来使煅烧产物顺利出料。同时煅烧条件的变化会导致煅烧产物物理化学性质发生变化。采用动力堆燃耗45 GWd/t(以U计)乏燃料后处理产生的模拟高放废液,研究了不同温度、不同转速条件下煅烧产物的粒径分布、含水量、振实密度、脱硝率等物理化学性质,研究结果显示:升高煅烧温度可以使煅烧产物粒径更加均匀,当煅烧温度在600～700℃、转速在15～20 r/min时,煅烧产物的含水率小于2%,振实密度在1.7 g/cm³左右,脱硝率能达到99%以上,煅烧过程中的粘壁现象较少,能实现煅烧过程中的顺利出料。