聚酰亚胺/二氧化硅杂化膜的制备与介电性能的研究

采用溶胶-凝胶法制备了BTDA-ODA聚酰亚胺/SiO2杂化膜,利用红外分光光度计（FTIR）、热重分析仪（TGA）和透射电镜（TEM）研究了杂化膜的微观结构和热性能,并对杂化膜的介电常数（e）和介电损耗（tand）随SiO2粒子含量和电场频率的变化进行了分析和讨论。结果表明：杂化膜的介电常数和介电损耗随SiO2粒子含量的增加而增大,随电场频率的升高而逐渐降低,用考虑到粒子的形状因素和两相间相互作用的EMT模型可以预测聚酰亚胺/SiO2杂化膜的介电常数。     

一体化复合式膜生物反应器除磷研究

本文通过对比实验，研究了不同工艺组合条件下一体化复合式膜生物反应器（HCMBR）的除磷效果，研究表明，在无厌氧段的情况下，反应器内保持好氧状态的同时，填料内部存在厌氧环境，TP的去除率为22％，在有厌氧段（A／O）的情况下，TP的去除率可达70％，采用化学方法时，TP去除率可达82．1％，但过高的n(Al^3 )/n(TP)值将会影响污泥的活性，并且HCMBR对NH3－N，CODCr,TN等污染物有十分良好的去除效果。     

有机杂化阻尼材料动态力学性能的影响因素探讨

高分子阻尼材料作为一类环保功能材料,将向高性能、宽温域的方向发展。传统的阻尼改性方法(如共混、共聚、无机杂化等)及近年来发展起来的互穿聚合物网络和添加压电陶瓷等研究手段都存在一定的局限性。新近开发的利用有机小分子与极性高聚物形成杂化体的方法所得到的阻尼材料的性能非常突出,是一种很有前途的阻尼改性新方法。本文在对现有的二元、三元杂化体系进行分析对比的基础上,对影响有机杂化阻尼材料动态力学性能的因素进行了探讨,为今后该领域的研究工作提供参考。     

NCO含量对聚氨酯-丙烯酸酯复合乳液性能的影响

以甲苯二异氰酸酯(TDI-80)、聚醚二元醇(N210)、二羟甲基丙酸(DMPA)和甲基丙烯酸甲酯(MMA)为主要原料，采用原位乳液聚合法，合成聚氨酯-丙烯酸酯(PUA)复合乳液。在保证DMPA含量、中和度等不变的情况下，研究了NCO／OH物质的量之比对乳液的性能及外观的影响。     

Quadratic control of stochastic hybrid systems with renewal transitions

We study the quadratic control of a class of stochastic hybrid systems with linear continuous dynamics for which the lengths of time that the system stays in each mode are independent random variables with given probability distribution functions. We derive a condition for finding the optimal feedback policy that minimizes a discounted infinite horizon cost. We show that the optimal cost is the solution to a set of differential equations with unknown boundary conditions. Furthermore, we provide a recursive algorithm for computing the optimal cost and the optimal feedback policy. The applicability of our result is illustrated through a numerical example, motivated by stochastic gene regulation in biology.     

小型无人机C／G复合材料尾撑杆的研制

本文介绍了复合材料管件（无人机尾撑杆）的结构与铺层设计、基体树脂选择和成型工艺以及性能测试等内容。     

Delay time compensation based on coefficient of restitution for collision hybrid motion simulator

A hybrid motion simulator embeds a hardware experiment in a numerical simulation loop. However, it is often subjected to the inherent problem of an energy increase in the collision of two pieces of hardware in a loop because of the delay time. This paper proposes a delay time compensation method based on contact dynamics model for a collision hybrid motion simulator under delay time and establishes a compensation method for coupled translational and rotational motion. The model developed in this paper describes linear uniform motion of a floating object during the period of the delay time until the force and torque are observed and non-linear motion according to environmental stiffness after the initial delay time period in contact. By using the above model, compensation parameters are designed based on desired coefficient of restitution with iterative calculation. The proposed method achieves accurate delay time compensation and simultaneously realizes a variable desired coefficient of restitution over a wide range of frequencies. Furthermore, the compensation method for multi-dimensional motion is established under the assumption that the friction effect is very small. The efficiency of the proposed method is verified through collision experiments for the coupled motion in two dimensions.     

THROO: a Tracked Hybrid Rover to Overpass Obstacles

In this paper, the design, simulation and experimental tests are presented for THROO: a Tracked Hybrid Rover, which has been developed to Overpass Obstacles. The proposed mobile robot has 3-DOFs and it is capable of straight motion, turning ability and two operations, namely rover-like motion with tracks on flat terrain and walking-like motion with track and legs to overpass obstacles to move on uneven terrain. The leg mechanism is composed of a four-bar linkage, which has been synthesized according to the desired features. In particular, the Burmester problem, which aims at finding the geometric parameters of a four-bar linkage required for a prescribed set of finitely separated poses are solved for the case understudy. Dynamic simulations have been carried out and a prototype has been built. The proposed results show the hybrid rover ability to overpass obstacles, for which size is comparable or greater than the track high.     

Characterization of poly(vinyl pyrrolidone‐co‐isobutylstyryl polyhedral oligomeric silsesquioxane) nanocomposites

Poly(vinyl pyrrolidone‐co‐isobutyl styryl polyhedral oligomeric silsesquioxane)s (PVP–POSS) were synthesized by one‐step polymerization and characterized using FTIR, high‐resolution ¹H‐NMR, solid‐state ¹³C‐NMR, ²⁹Si‐NMR, GPC, and DSC. The POSS content can be controlled by varying the POSS feed ratio. The T_g of the PVP–POSS hybrid is influenced by three main factors: (1) a diluent role of the POSS in reducing the self‐association of the PVP; (2) a strong interaction between the POSS siloxane and the PVP carbonyl, and (3) physical aggregation of nanosized POSS. At a relatively low POSS content, the role as diluent dominates, resulting in a decrease in T_g. At a relatively high POSS content, the last two factors dominate and result in T_g increase of the PVP–POSS hybrid. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2208–2215, 2004