A comparative study on optimised and non‐optimised axial flow,spherical reactors in naphtha reforming process

In this study, the operating conditions of an axial flow spherical reactor have been optimised using a reliable optimisation technique and the results are compared with the results of non‐optimised conditions. The dynamic behaviour of the reactor has been considered in the optimisation process and orthogonal collocation method has been used in order to solve the obtained equations from mathematical modelling of the process. The goal of this study is to maximise the aromatics and hydrogen production rate. Therefore, the objective function is the combination of two terms which include the production rate of the mentioned components. The catalyst distribution for each reactor, the inlet pressure of the system, Length per radius for each reactor, the naphtha feed molar flow rate and the hydrogen mole fraction in the recycle stream as well as the inlet temperature of each reactor have been optimised in this study. © 2011 Canadian Society for Chemical Engineering     

球型支座转动探讨

介绍了桥梁球型支座的竖向转动性能,研究了支座承受水平载荷后的转动机构,并对三种改进后的支座结构的优缺点进行了归纳总结,指出在实际工程中应通过支座所承受的不同水平载荷选择不同的支座结构,以确保球型支座转动性能的稳定。     

Steady-state thermal heat conductivity in rotor of ball asynchronous motor

The problem of how to develop a mathematical model of the heat processes that take place in the rotor of a spherical asynchronous motor under the influence of internal heat sources is considered. An analytic model of the process is suggested that makes it possible to solve the problems of determination of the extreme thermal modes of a motor and is well suitable for the searching procedures of the construction optimization problems.     

Visualization of Knoop Indentation Damage of Silicon Nitride by Plasma Etching

A visualizing technique for indentation damage of ceramics was developed. Plasma etching was used to enhance the view of cracks and the subsurface microcracking crush zone following Knoop indentation of hot pressed Si₃N₄. The microcracking zone was readily identified from the surface view of the indented surface as a grain-falling-off region (GFOR), defined as a region in which grains were removed by preferential etching using CF₄ gas, followed by ultrasonic cleaning. A fissure-like opening corresponding to the indentation cracks was also observed. It is inferred that the formation of the GFOR region and the fissure-like opening were caused by the etching/cleaning treatment. Meanwhile, the etching on a section which included diagonals of the impression provided a section view of the microcracking zone.     

超音速火焰喷涂NiTi合金涂层的形状记忆效应

采用超音速火焰喷涂制备超致密NiTi合金涂层,通过后续热处理获得优化相变结构,并通过压痕法分析涂层的形状记忆效应。光学显微镜及扫描电镜对NiTi合金涂层微观结构表征显示,喷涂制备态涂层由内部岛状-链状界面叠片组成,涂层致密孔隙率约为0.82%。X射线衍射分析显示,NiTi涂层制备态为全奥氏体,经时效处理析出Ni₄Ti₃相。压痕法分析表明,在制备态及时效态涂层中均获得了一定的单程及双程形状记忆效应。X射线物相分析及差示扫描量热仪对比分析揭示,时效析出的第二相粒子显著增加形状记忆效应。     

Li[Li_(0.2)Ni_(0.2)Mn_(0.6)]O_2富锂正极材料的制备及性能研究

通过液相法制得了球形Ni(OH)2,再与Mn(NO3)2、CH3COOLi通过固相法制备了富锂正极材料Li[Li0.2Ni0.2Mn0.6]O2。通过X射线衍射光谱法(XRD)、扫描电子显微镜法(SEM)、粒度分析仪、循环伏安、交流阻抗以及充放电测试对样品的结构、形貌和电化学性能进行了表征。结果表明,合成温度为900℃时,材料结晶度高,阳离子混排程度低,颗粒表面光滑均一;在20 m A/g时,首次放电比容量为174.02 m Ah/g,在60 m A/g的高倍率放电条件下比容量仍可达到80.56m Ah/g。     

球形四氧化三锰合成锰酸锂的性能

分别以湿法沉淀的球形四氧化三锰(Mn3O4)和商业电解二氧化锰(EMD)为锰源合成锰酸锂(Li Mn2O4)。通过杂质含量分析、XRD、SEM和充放电测试等,研究锰源对产物性能的影响。以粒度为10μm的球形Mn3O4为原料合成的Li Mn2O4保留了锰源的物化特征,以1.0 C在3.00~4.35 V充放电,首次放电比容量为117.2 m Ah/g,常温、55℃高温循环100次的容量保持率分别为94.6%和91.0%,高于以EMD为原料合成的Li Mn2O4(分别为87.9%和72.9%)。循环性能的提高,与球形Li Mn2O4的粒度分布集中、比表面积小及杂质含量低有关。     

面向球面虚拟实景底部空洞的快速修补算法

本文提出一种针对球面虚拟实景底部空洞的快速修复算法,首先获取球面全景与球面虚拟实景间映射关系,并基于不同时刻球面虚拟实景间的空间位置关系建立位置映射模型,然后通过求解得到不同时刻球面全景之间的对应关系并实现缺失部分的修补,最后通过对修补区域亮度的调整及边缘融合,对修补结果进行优化.理论分析和实验结果均表明,该方法利用底部空洞位置固定这一特点建立复杂度仅为O(n)的修补算法,能够快速有效的实现球面实景底部空洞的修复.     

某球形雷体结构的毁伤特性数值研究

为合理设计反水雷武器的尺寸及重量、提高作战效率,对某球形雷体结构的毁伤特性数值进行研究。运用LS-DYNA软件开展水下静爆仿真,采用3维模型求解;分析裸药柱与某球形雷的作用距离、裸药柱装药量对雷体壳体毁伤的影响特性。结果表明：当裸药柱外端面与雷体壳体外缘的距离从210 mm增加到400 mm时,壳体变形量从3.9%降低到2.2%;裸药柱装药量从0.5 kg增加至2.5 kg,壳体变形量从0.58%降到3.4%;增大裸药柱装药量更能使雷体壳体结构加大塑性变形;确定造成雷体壳体毁伤的临界装药量为3 kg,临界距离为20 mm。