单级单开关不连续导电模式功率因数校正电路新方案

分析了几种单级单开关不连续导电、带输出电压隔离的功率因数校正电路，分别讨论了其优缺点，并提出了一种新的功率因数校正电路。     

回转窑窑壁非稳态传热模型及窑皮厚度优化

烟气、料床、窑壁是回转窑传热过程的三要素,在确定这三要素之间传热量的基础上,建立了回转窑窑壁非稳态传热数学模型。对中铝河南分公司2号窑窑壁的非稳态传热过程进行了数值计算。结果表明:窑体旋转一周,烧成带窑壁内表面温度将在1 232~1 334℃变化,这易导致窑壁热疲劳破坏;窑皮越厚,窑壁的径向温度梯度越小,热应力越低;将烧成带窑皮厚度控制在252 mm,可使烧成带窑壁外表面温度维持在200℃。     

La0.6Sr0.4Co1-yFeyO3钙钛矿复合氧化物的结构与电学性能

采用固相反应法合成出La0.6Sr0.4Co1-yFeyO3体系复合氧化物样品，XRD分析结果证实不同Co／Fe比例的样品中均形成菱形六面体钙钛矿结构，采用固相烧结法制备出致密的La0.6Sr0.4Co1-yFeyO3体系陶瓷。研究结果表明，在室温到900℃温度范围内La0.4Sr0.4CoO3(y=0)的电导率随温度的增加而单调降低，其它Co／Fe比例样品的电导率随着温度的增加出现最大值，电导率达到最大值的温度随Co／Fe比例的降低而提高。在低温段，La0.6Sr0.4Co1-yFeyO3体系的导电行为符合小极子导电机制，导电活化能随Co／Fe比例的降低而增加。     

石油钻采阀门内壁热丝TIG堆焊

石油钻采专用阀门的使用有耐强腐蚀性要求，制造时需在内壁表层堆焊耐腐蚀材料。此类阀门具有质量大、形状特殊、焊接可达性差，焊接质量要求严格等特点；重点介绍了Fronius热丝TIG焊工艺和ETR全自动堆焊设备在阀门堆焊制造上的应用。     

高层住宅结构设计

主要介绍长沙梦泽园高层住宅从基础到上部楼层各部位的结构设计,以及在设计、施工过程中所考虑的一些问题及处理方法。     

Electrodiffusion diagnostics of the flow and mass transfer inside a network of crossing minichannels

The global mass transfer and the local flow structure inside a set of crossing minichannels were characterized using the electrodiffusion method. The individual square-cross channel sections (a = 1.5 mm in sides) intersect at right-angles in order to form the flow cell. An array of 39 circular platinum electrodes (0.25 mm in diameter) was flush-mounted into the wall of the flow cell to investigate the wall shear rate at different locations. This array of small sensors allowed characterization of longitudinal and lateral variations in wall shear rate across the flow cell, flow distribution at the inlet and outlet sections, transition between laminar and turbulent flow regimes, and flow behaviour at the channel crossings. The results of global wall mass transfer measurements demonstrated that, from a mass transfer point of view, the flow cell exhibits similar behaviour to a porous medium.     

Structural and transport effects of doping perfluorosulfonic acid polymers with the heteropoly acids, H3PW12O40 or H4SiW12O40

A perfluorosulfonic acid (PFSA) polymer with pendant side chain -O(CF₂)₄SO₃H was doped with the heteropoly acids (HPAs), H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀. Infrared spectroscopy revealed a strong interaction between the HPA and the PFSA ionomer. Modes associated with the peripheral bonds of the HPA were shifted to lower wave numbers when doped into PFSA membranes. Small-angle X-ray scattering (SAXS) measurements showed the presence of large crystallites of HPA in the membrane with d spacings of ca. 10 Å, close to the lattice spacing observed in bulk HPA crystals. Under wet conditions the HPA was more dispersed and constrained the size of the sulfonic acid clusters to 20 Å at a 5 wt% HPA doping level, the same as in the vacuum treated ionomer samples. Under conditions of minimum hydration the HPA decreased the E_a for the self-diffusion of water from 27 to 15 kJ mol⁻¹. The reverse trend was seen under 100% RH conditions. Proton conductivity measurements showed improved proton conductivity of the HPA doped PFSAs at a constant dew point of 80 °C for all temperatures up to 120 °C and at all relative hummidities up to 80%. The activation energy for proton conduction generally was lower than for the undoped materials at RH ≤80%. Significantly the E_a was 1/2 that of the undoped material at RHs of 40 and 60%. A practical proton conductivity of 113 mS cm⁻¹ was observed at 100 °C and 80% RH.     

POWER CONSUMPTION WITH ANCHOR MIXERS EFFECT OF BOTTOM CLEARANCE

The effect of bottom clearance on power draw for anchors is investigated. The results suggest that power input decreases as the bottom clearance ratio b/D increases. A new correlation is proposed in which both bottom and wall clearance effects on power input are considered. The dependence of power input on these effects is additive rather than multiplicative. Thus, the total power consumption is the sum of the power inputs generated by the wall and bottom clearance. Power results from 3D-CFD numerical simulations are also presented. These results confirm fairly well the experimental points.     

金属闪光外墙乳胶漆的研制及性能研究

以丙烯酸酯及有机硅单体为原料合成了核-壳型硅丙乳液,用自制分散剂将闪光铝粉分散成水性闪光铝粉浆,并成功分散于硅丙乳液中,加入进口助剂,配制成水性金属闪光外墙乳胶漆.讨论了基料的玻璃化温度、单体的加入方式、引发剂、乳化剂、反应温度、聚合工艺和pH等对乳胶漆性能的影响.     

垂直管内弹状气泡上升中壁面传递的实验研究

垂直管内弹状流壁面传递是诸多工业应用中需研究的重要问题之一。今用极限扩散电流技术,对弹状气泡上升时瞬时壁面剪应力和传质系数进行了测定,结果显示:当基于表观气速的Froude数FrG < 0.74时,壁面剪应力随弹状气泡和液塞的到来呈现方向相反的交替变化,壁面传质系数亦相应变化;而当FrG > 0.74时,剪应力方向一直向下,说明液膜向下流动,且弹状气泡和液塞的到来对壁面传质系数的影响很小。这说明下落液膜射流穿透了液塞段,控制了整个壁面传递过程。研究还对下落液膜区、尾迹区及液塞段的不同传递特征及机理进行了分析, 并结合气泡塔熔融结晶器中弹状气泡上升时的传热,对结晶操作条件的合理选择进行了讨论。