POSS基低介电常数多孔薄膜的制备与性能研究

通过4，4’-二（4-烯丙氧基苯甲酸）苯酯与POSS分子的硅氢化反应，合成了POSS交联聚合物。用FTIR、XRD对聚合物结构进行了表征，利用椭偏仪测量了薄膜的折射率和介电常数。通过改变单体与POSS投料摩尔比，可制备出k＜2.5的低介电常数薄膜。     

A rapid forming method and simulation on controllable-porosity coating

A new method was introduced to fabricate porous coating and control its porosity by changing spray parameters. Two models were constructed to simulate the deformation of droplet and the deposition process of splats on substrate. Considering the gap-pore, step-pore and shield-pore in the presented models, the influence of spray angle on the porosity of coating was mainly investigated. The simulation and experimental results show that the presented method is suitable for fabricating controllable-porosity coating. The porosity of coating can reach 49%. When the spray angle is lower than 30°, the porosity of coating rapidly increases because of shielding effect. Moreover, powder size and impact velocity also influence the porosity. Besides, a new forming method of graded porous coating was simulated by continuously changing the spray angle.     

薄层底水油藏部分打开直井试井解释方法研究

底水油藏在我国较为常见,建立了薄层底水油藏瞬时点源扩散方程,利用Lord Kelvin点源解、叠加原理、镜像反应等获得了该类油藏渗流微分方程的基本解,利用Poisson叠加公式简化表达式,结合点源函数的思想求解了薄层底水油藏直井压力响应函数,计算得到了无因次压力和压力导数双对数理论图版,并在此基础上分析了薄层底水油藏直井渗流特征及其影响因素,编制了试井解释软件.     

玉米多孔淀粉吸附性能研究

研究玉米多孔淀粉对次甲基蓝的吸附特性,借助于全自动气体吸附仪和分光光度计等仪器研究多孔淀粉的孔结构参数和对次甲基蓝色素的的吸附动力学特征,并建立多孔淀粉的等温吸附方程及其吸附速率方程.在柱吸附过程中,多孔淀粉吸附次甲基蓝的最佳吸附浓度为6×10-5mol/L,多孔淀粉对次甲基蓝的饱和吸附量为1.41 mg/g,且270 min达到饱和吸附量.结果表明,与原淀粉相比,多孔淀粉的比表面积、比孔容、孔径大小均增大,这说明多孔淀粉是良好的吸附载体,能够吸附更多功能性目的物质.     

周期性多孔低介电常数材料机械特性的表面波测量模型

研究了纳米通孔的分布对于表面波方法测量多孔低介电常数薄膜机械特性的影响,提出了用横观各向同性表征周期性多孔介质材料结构特性的表面波传播理论模型,给出了表面波在low-k薄膜/Si基底分层结构中的传播方程.通过数值算例揭示出表面波在不同传播方向的频散特性,以及low-k薄膜的弹性常数即杨氏模量E,E'和剪切模量G'对频散特性的影响.结果表明E'和G'在垂直于通孔的传播方向不能被测出.     

Effect of eggshell powder as nucleating agent on the structure,morphology and functional properties of normal corn starch foams

Corn starch and eggshell powder (with particle sizes of 4–5µm and 8–10µm) composite foams were prepared by extrusion. Effects of eggshell on the structure, morphology, physical properties (unit density and expansion ratio), mechanical properties (spring index and compressibility) and thermal behaviour (thermal transition and stability) of the foams were investigated. Foam cell size decreased and cell population increased with addition of eggshell into starch matrix. The foam unit density, expansion ratio and compressibility decreased significantly (p < 0.05), while the spring index increased significantly (p < 0.05) as the eggshell content increased from 0 to 6wt%. Further increasing eggshell content to 10wt% increased the unit density and compressibility and decreased the expansion ratio and spring index. The thermal transition and stability increased with the addition of eggshell. The optimum eggshell content was 6wt% and the smaller‐sized eggshell powder had a favourable effect on the functional properties of the foams. Copyright © 2006 John Wiley & Sons, Ltd.     

Controlled synthesis of porous spinel cobalt manganese oxides as efficient oxygen reduction reaction electrocatalysts

In this article, we report a facile precursor pyrolysis method to prepare porous spinel-type cobalt manganese oxides (Co _x Mn_3-x O₄) with controllable morphologies and crystalline structures. The capping agent in the reaction was found to be crucial on the formation of the porous spinel cobalt manganese oxides from cubic Co₂MnO₄ nanorods to tetragonal Co₂Mn₄ microspheres and tetragonal Co₂Mn₄ cubes, respectively. All of the prepared spinel materials exhibit brilliant oxygen reduction reaction (ORR) electrocatalysis along with high stability. In particular, the cubic Co₂MnO₄ nanorods show the best performance with an onset potential of 0.9 V and a half-wave potential of 0.72 V which are very close to the commercial Pt/C. Meanwhile, the cubic Co₂MnO₄ nanorods present superior stability with negligible degradation of their electrocatalytic activity after a continuous operation time of 10,000 seconds, which is much better than the commercial Pt/C electrocatalyst.

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