An immune orthogonal learning particle swarm optimisation algorithm for routing recovery of wireless sensor networks with mobile sink

The growth of mobile handheld devices promotes sink mobility in an increasing number of wireless sensor networks (WSNs) applications. The movement of the sink may lead to the breakage of existing routes of WSNs, thus the routing recovery problem is a critical challenge. In order to maintain the available route from each source node to the sink, we propose an immune orthogonal learning particle swarm optimisation algorithm (IOLPSOA) to provide fast routing recovery from path failure due to the sink movement, and construct the efficient alternative path to repair the route. Due to its efficient bio-heuristic routing recovery mechanism in the algorithm, the orthogonal learning strategy can guide particles to fly on better directions by constructing a much promising and efficient exemplar, and the immune mechanism can maintain the diversity of the particles. We discuss the implementation of the IOLPSOA-based routing protocol and present the performance evaluation through several simulation experiments. The results demonstrate that the IOLPSOA-based protocol outperforms the other three protocols, which can efficiently repair the routing topology changed by the sink movement, reduce the communication overhead and prolong the lifetime of WSNs with mobile sink.     

Profit optimisation of the multiple-vacation machine repair problem using particle swarm optimisation

This paper investigates a multiple-vacation M/M/1 warm-standby machine repair problem with an unreliable repairman. We first apply a matrix-analytic method to obtain the steady-state probabilities. Next, we construct the total expected profit per unit time and formulate an optimisation problem to find the maximum profit. The particle swarm optimisation (PSO) algorithm is implemented to determine the optimal number of warm standbys S* and the service rate μ* as well as vacation rate ν* simultaneously at the optimal maximum profit. We compare the searching results of the PSO algorithm with those of exhaustive search method to ensure the searching quality of the PSO algorithm. Sensitivity analysis with numerical illustrations is also provided.     

无载体Fe／Zn超细粒子催化剂的磁学性质

根据铁的磁性特点，借助磁性测试方法，研究了ＦＴ合成Ｆｅ／Ｚｎ超细粒子催化剂的磁学性质，并考察了样品还原后磁学性质的变化，利用程序升温热磁还原法（ＴＰＲＭ）对样品在程序升温还原过程中磁性的变化进行了跟踪，发现锌对铁的还原行为有显著影响，锌对铁的还原有抑制作用，并能够稳定二价铁，使其不易被进一步还原到零价态，针对样品的超细粒子的特点，观察了其超顺磁现象。     

逆凝聚包覆法制备硫黄调节型粉末氯丁橡胶 Ⅰ.粒径分布

采用逆凝聚包覆法制备硫黄调节型粉末氯丁橡胶(PCR)并考察加料方式、搅拌转速和胶乳加人流速对产物粒径分布的影响。建立氯丁胶乳的逆凝聚粉末化模型并采用均匀试验设计的方法对该模型进行了验证。验证结果表明，该模型可以有效地模拟PCR的逆凝聚包覆氯丁胶乳的粉末化过程。PCR产物中粒径1～3mm的中等粒子的质量分数仅与搅拌转速有关，表明湍流爆裂是产生中等粒子的主要原因，而带状拉伸则是产生较粗颗粒和细小粒子的主要原因。扫描电子显微镜观察发现，采用逆凝聚包覆法制备的PCR粒子为单颗连续粒子，即产物粒子由单颗胶乳液滴凝聚而成。     

旋风分离器两相流研究综述

综述了旋风分离器内部流场、颗粒运动和数值计算模型的理论研究发展历程。     

Assessing the predictive capability of two‐phase models for the mechanical behavior of alumina/epoxy nanocomposites

A review of analytical modeling of particulate reinforcement is made as a prelude to the problem of microstructural inhomogeneity in nanocomposite materials. Noting the inevitability of dispersion nonuniformity, and variations in agglomerate morphology and filler‐matrix interaction, the need to question the application of such models to novel materials arises. Employing the mechanical properties of alumina/epoxy nanocomposites, with known dispersion characteristics, an evaluation of the predictive capability of various models for Young's modulus, strength, and failure strain is made. Comparison between models is accompanied by a discussion of the parameters used in the fitting of macroscopic behavior to microstructural features. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 869–879, 2005     

两步法合成大粒径丁苯胶乳

研究了聚甲基丙烯酸甲酯（MMA）对丁苯（BS）胶乳的附聚作用以增大丁苯胶乳粒径；探讨了无机盐、体系pH值及体系中MMA胶乳与BS胶乳的固含量比（R值）对附聚后丁苯胶乳的粒径及稳定性的影响。结果表明：适当添加无机盐可以稳定胶乳体系，最佳用量（质量分数）为0．1％～0．2％；适当增大体系pH值，可增大胶乳粒径；在附聚过程中，当R值在两个附聚峰附近时，可增大丁苯胶乳的粒径。     

致孔剂溶胀法制备多孔结构的乳胶粒

以苯乙烯、二乙烯基苯为单体 ,在传统乳液聚合阶段引入甲苯和庚烷作为单体的混合溶剂 (致孔剂 ) ,使溶剂在聚合中进入乳胶粒子内部 ,聚合完成后 ,通过水蒸气蒸馏的方法将致孔剂带出 ,以形成多孔结构乳胶粒。本文考察了单体和致孔剂比例、致孔剂中甲苯和庚烷的比例对反应速率、单体转化率及多孔结构乳胶粒的影响 ,结果表明 :单体和致孔剂比例为 2∶1、致孔剂中甲苯和庚烷的比例为 2∶1时 ,能够得到清晰结构多孔乳胶粒。     

沙棘柔性坝拦沙效应的试验研究

在野外试验基地进行了沙棘柔性坝拦沙效应试验。基于试验数据,分析了不同含沙水流条件下沙棘柔性坝对沿程含沙量及出入口悬沙粒径分布的影响,并探讨了沙棘柔性坝的阻力特性。结果表明,沙棘柔性坝对不同含沙水流的拦沙效果显著不同,对原型沙B的拦截效果最好,其次为原型沙A,最后为模型沙。对250~1 000μm粒径范围内的原型沙拦截效果最佳,且原型沙含沙量与中值粒径之间呈现正相关关系,对100~1 000μm粒径范围内的模型沙的拦截效果较好。各不同含沙水流条件下的沿程含沙量主要受沙棘柔性坝阻力的影响。本研究有助于深入理解沙棘柔性坝的拦沙效应,并对沙棘植物柔性坝这一生态工程在砒砂岩区沟道的推广应用提供理论依据。     

Role of anionic and nonionic surfactants on the control of particle size and latex colloidal stability in the seeded emulsion polymerization of butyl methacrylate

The evolution of the main colloidal parameters in the seeded starved‐feed semi‐continuous emulsion polymerization of butyl methacrylate (BMA) was investigated, with the main purpose of assessing the effectiveness of the semi‐empirical relationship S = K · S_S · ΔA/A_S as a tool to define the surfactant/monomer feed ratio (∝ K) best suited to achieve a target particle size. In particular, the effect of the type and amount of surfactant [i.e., anionic, sodium dodecyl sulfate (SDS), or nonionic, Brij 58P] added during the semi‐continuous stage was considered. Coagulum formation was never observed under the adopted experimental conditions. To detect the occurrence of secondary nucleation or particle aggregation, or both, the particle size and number of particles, the surface tension and the particle surface coverage ratio were correlated. The best results were obtained with SDS and 0.8 ≤ K ≤ 3. In fact, under the selected experimental conditions, only with SDS did the number of particles remain nearly constant throughout the polymerization at the value defined by the seed latex; the particle size distribution was highly monodisperse, and the final particle diameter closely matched the calculated one (～ 120 nm). The above semi‐empirical relationship based on the adjustable parameter K was validated by running test polymerizations aimed at lattices with well‐defined particle size. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3083–3094, 2006