一种激光测厚装置

介绍一种新型激光测厚装置 ,描述了它的结构框架及工作过程     

Elastic solutions of a cylindrical rod containing periodically distributed inclusions with axisymmetric eigenstrains

Summary. In this paper, we give the elastic solution for a special type of microstructure – a circular cylindrical rod containing periodically distributed inclusions along its axial direction. Each inclusion has the same uniform axisymmetric transformation strain (eigenstrain). Analytical elastic solutions are obtained for the displacements, stresses and elastic strain energy of the rod. The effects of microstructure and its evolution (growth of inclusions) on the elastic stress and strain fields as well as the strain energy of the rod are quantitatively demonstrated. As a result of such microstructure evolution nominal stress-strain relation with strain softening is derived for a rod under uniaxial tension.     

Courtesy piggybacking: supporting differentiated services in multihop mobile ad hoc networks

Due to the salient characteristics such as the time-varying and error-prone wireless links, the dynamic and limited bandwidth, the time-varying traffic pattern and user locations, and the energy constraints, it is a challenging task to efficiently support heterogeneous traffic with different quality of service (CoS) requirements in multihop mobile ad hoc networks. In the last few years, many channel-dependent mechanisms are proposed to address this issue based on the cross-layer design philosophy. However, a lot of problems remain before more efficient solutions are found. One of the problems is how to alleviate the conflict between throughput and fairness for different prioritized traffic, especially how to avoid the bandwidth starvation problem for low-priority traffic when the high-priority traffic load is very high. In this paper, we propose a novel scheme named Courtesy Piggybacking to address this problem. With the recognition of interlayer coupling, our Courtesy Piggybacking scheme exploits the channel dynamics and stochastic traffic features to alleviate the conflict. The basic idea is to let the high-priority traffic help the low-priority traffic by sharing unused residual bandwidth with courtesy. Another noteworthy feature of the proposed scheme is its implementation simplicity: The scheme is easy to implement and is applicable in networks using either reservation-based or contention-based MAC protocols.     

甲基丙烯酸三氟乙酰氧乙酯的聚合

对甲基丙烯酸三氟乙酰氧乙酯(TFAOEMA)的阴离子聚合及原予转移自由基聚合进行了研究。常用的阴离于引发剂如丁基锂、1，1-二苯基已基锂等很难引发TFAOEMA的阴离子聚合，而碱性较弱的引发剂如三乙基铝却容易引发，且产率较高。以氯化亚铜、五甲基二乙基三胺、溴代丙酸乙酯为引发体系的TFAOEMA的本体原子转移自由基聚合符合活性聚合特征。但在四氢呋喃为溶剂的原子转移自由基聚合中却存在活性中心失活现象。以末端含卤素的聚甲基丙烯酸甲酯为大分子引发剂，引发TFAOEMA的原子转移自由基聚合，得到了含氟双嵌段聚合物。     

PMMA tacticity and alumina powder dispersion stability

Summary Sedimentation experiments and X-ray photoelectron spectroscopy (XPS or ESCA) analyses have been used to study the effect of poly(methylmethacrylate) (PMMA) tacticity on aluminum oxide powder dispersion stability in a common solvent medium. The relative trends from sedimentation densities, and from surface analyses after solvent washing show that (PMMA) adsorption is greatest with isotactic polymer, where isotactic>atactic>syndiotactic adsorption. These results suggest that surface adsorption and hence dispersion stability can be influenced by polymer chain configuration as well as by chain conformation.     

火电厂实施废水零排放的可行性探讨

对合肥发电厂的用排水现状进行了介绍，并提出了实施废水零排放的可行性方案。     

Dynamic Bending Strains in Planar Trusses with Pinned or Rigid Joints

The method of reverberation ray matrix is applied to analyze the dynamic behavior of structural members in trusses with pinned joints subjected to suddenly applied force. The results are compared with those in planar trusses with rigid joints. Detailed calculations are made with two types of trusses, a small laboratory model made of slender aluminum bars, and a hypothetical real size Pratt truss made of structural steel. It is found that the maximum dynamic bending strains in the members of both types of trusses are very large, comparable with the dynamic axial strains in the same member. The magnitudes of bending strains in the pinned truss differs little from those in the truss with rigid joints for both types of trusses. Such a large dynamic bending strain in a structure member, which is contradictory to the static behavior of the same truss, could be caused by the inertial force of the mass in structural members of the truss.     

Low cycle fatigue and creep behavior of recrystallized Molybdenum near room termperature

The deformation behavior of pure recrystallized molybdenum under cyclic and static loads was investigated in the temperature range between 30°C and 10O°C, for stress amplitudes between 100 MPa and 250 MPa and for static loads up to 200 MPa. The results show that in spite of the low test temperatures and stress levels the Mo material exhibits considerable plastic strains which depend sensitively on frequenez and small changes in temperature.The activation energy deduced for the static and dynamic deformation is less than 0.98 eV which indicates thermally activated processes, to be explained by a dislocation kink model as described in the literature. The low-temperature fatigue behavior appears strongly influenced by creep-fatigue interaction phenomena.     

单晶高温合金DD3亚结构超细化定向凝固工艺研究EI

利用ＺＭ定向凝固装置研究了镍基单晶高温合金ＤＤ３在高温度梯度（７００～１２００Ｋ／ｃｍ）定向凝固条件下的微观组织演化特征及其对工艺参数的响应函数，结果表明：该合金在高界面温度梯度条件下，柱晶生长速度范围向高速区扩展，从而使单晶亚结构细化成为可能。所得单晶棒中亚结构一次间距可比传统ＨＲＳ法定向凝固籽晶中相应尺度减小５～１０倍。本文还对其组织演化机制进行了分析。