Preparation and properties of magnetorheological elastomers based on silicon rubber/polystyrene blend matrix

Magnetorheological (MR) elastomers, which are mainly composed of magnetic particles and elastic polymer, are a new kind of smart materials whose modulus can be controlled by changing the strength of magnetic fields. In this article, MR elastomers based on immiscible silicon rubber/polystyrene (SR/PS) blend matrix were fabricated successfully via cosolvent method and the MR effect, electric and mechanical properties, and the microstructures of the corresponding materials were studied. SEM studies showed that the dispersion of iron particles in blend matrix were different from that in single polymer, which could be further proved by the different electric conductivity. The MR effect of MR elastomers based on blend matrix varied with the different ratios of SR and PS, which was discussed in detail from the special dispersion of iron particles and of zero‐modulus of MR elastomers. In addition, the MR elastomers based on SR/PS blend matrix had enhanced mechanical properties, which made them more hopeful to be applied in practice. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3143–3149, 2007     

发酵法生产医药用透明质酸

山东临朐华元生物工程有限公司通过对菌株的筛选培育、发酵原料配方和工艺的改进、提纯工艺和设备的优化、制粉工艺和设备的改进、生产环境的改造,利用生物工程技术发酵法研制生产出医药用透明质酸,并形成1.5t/a的生产规模。产品应用于眼科手术、滴眼液、手术防粘连等方面,改变了国内医药用透明质酸依赖进口或动物器官提取法微量生产自用的局面,为国内以透明质酸为基质的制剂产品发展打下了基础。     

Modèles Hydrodynamiques pour la Séparation des Courants dans un Décanteur Pilote

Despite of its general use in industry, particle sedimentation is still a not well understood unit operation. Hydrodynamics is complex in essence, mainly because the possible volumes are depending on the operating conditions, which in turn has consequences on the stability of the equipment in unsteady state conditions.     

齐鲁文化精神对中国传统体育文化的影响

本文主要论述了齐鲁文化所表现出来的和合精神、人道主义精神、厚德仁民精神、大公无私精神、自强不息精神等,对中国传统体育文化产生的重要影响。     

Dielectric and pyroelectric characteristics of the infrared sensitive (Pb1?xSrx)TiO3 ceramics

PST ferroelectric ceramics were fabricated successfully by a two-step method, i e first, PbTiO₃ and SrTiO₃ were sintered respectively, then mixed and sintered together. The process and characteristics of PST ferroelectric ceramics were introduced and researched. Their dielectric and pyroelectric characteristics are as follows dielectric constant 10⁴ order, low dielectric loss (lower than 3.0% in the working frequency range of 1–1 000 kHz), saturation polarization intensity 10⁻¹ C/m² order, and pyroelectric coefficient 10⁻³ C/m²·K order.     

最大Lyapunov指数实现局域网流量的预测

由于网络中存在复杂的非线性动力学特性,基于混沌理论,采用最大Lyapunov指数对局域网络流量序列进行预测分析,能够实现较早地预测出网络流量的突变特性.首先,采用相空间重构理论,并结合C-C算法将实际测试的流量时间序列投影到重构的相空间中.然后,计算其最大Lyapunov指数并对最大可预测时间进行了分析,同时对预测算法进行了研究.最后,对实际测试的局域网流量序列分别采用点预测和区间预测方法进行了分析.仿真结果显示,采用点预测方法对流量突变可以进行有效预测,突变越剧烈预测越准确;而采用区间预测可以有效预测流量的变化趋势,但不适用于广域网环境.进一步表明此方法能有效地利用所有数据信息进行预测,预测效果准确、可靠,可广泛的用于网络拥塞和网络攻击中.     

Preparation and electrochemical characterization of activated carbons by chemical-physical activation

A process was proposed based on the combination of chemical and physical activation for the production of activated carbons used as the electrode material for electric double layer capacitor (EDLC). By material characterization and electrochemical methods, the influences of the activitation process on the specific surface area, pore structure and electrochemical properties of the activated carbons were investigated. The results show that specific surface area, the mesopore volume, and the specific capacitance increase with the increase of the mass ratio of KOH to char (m(KOH)/m(char)) and the activation time, respectively. When m(KOH)/m(char) is 4.0, the specific surface area and the mesopore volume reach the maximum values, i.e. 1 960 m²/g and 0.308 4 cm³/g, and the specific capacitance is 120.7 F/g synchronously. Compared with the chemical activation, the activated carbons prepared by chemical-physical activation show a larger mesopore volume, a higher ratio of mesopore and a larger specific capacitance. Foundation item: Project(2007BAE12B01) supported by the National Key Technology Research and Development Program of China     

基于GHM多小波与自适应颜色迁移的信息隐藏算法研究

文章利用GHM多小波一阶变换后最低分辨率子图的4个分量能量分布特性以及自适应颜色迁移理论中lαβ域对颜色的控制力和自适应颜色迁移公式对象素的修改能力,提出基于GHM多小波变换和自适应颜色迁移理论的信息隐藏算法。算法在LL2中嵌入鲁棒参数,以RAID4方式在LH2和HL2中嵌入隐藏信息,在HH2中嵌入脆弱性标识。算法应用Chebyshev混沌映射和遗传算法改变嵌入信息顺序,提高了信息与载体一致性。实验表明,算法的不可见性平均提高24.43%,鲁棒性提高19.25%以上,且感知篡改能力敏锐。     

基于multi-agents的网络防卫体系中预警定位系统的研究与实现

传统的网络安全措施,如加密认证、防火墙和入侵检测系统等,虽然在保护信息的保密性、完整性、可用性和控制访问方面有一定的效果,但在协同和预警方面依然存在不足.文章提出了1个基于multi-agents的网络安全防卫系统,该系统由协同预警定位系统、协同审计系统、安全隔离系统、事故恢复系统等多个模块构成,模块之间由多个多级分层agents来负责通信任务.系统控制中心的agent server负责控制和协调整个安全体系,制定全网统一的安全控制策略.在该系统中,整个网络被划分成不同级别的分区,建立不同级别的协同预警定位系统,各分区既相互协作,又能够独立自治,通过协作的方式共同维护着整个网络的安全.在IPv6环境下测试的结果表明,该系统可以高效进行预警,IDS的捕获率约为95%、漏报率小于6%、误报率小于7%.     

基于小波分析和遗传神经网络的模拟电路故障诊断方法*

针对BP网络极易收敛于局部极小点与过拟合等缺点,在构建小波神经网络的基础上,提出用遗传算法优化BP神经网络的模拟电路故障诊断方法.该方法使用小波作为预处理工具,经PCA分析和归一化后提取输出信号的能量信息作为特征向量,用遗传BP神经网络作为故障识别器,对模拟电路故障进行诊断.与传统BP神经网络相比较,结果表明,该方法可明显改善神经网络结构、提高故障诊断的精度和速度.