结构振动状态输出的灰色预测主动反馈控制

针对主动即时控制中的时滞问题,提出了对结构振动状态（即输出）向量实施灰色预测即时主动控制,设计了结构的即时预测控制方案,推导了灰色预测方程,并用Mauab编程进行了仿真分析．将该方案应用于某房屋的抗震控制中,并将计算结果与理想的即时控制、不控制等工况的控制效果进行了比较,仿真结果显示采用灰色预测控制能有效减小时滞影响,控制效果较为理想．     

镁合金AM60表面改性及其在Hank's溶液中的腐蚀

采用等离子喷涂TiO2对镁合金AM60进行表面改性,利用扫描电子显微镜和能谱发现分别观察了涂层结构,分析了其化学成分,通过表面纳米划痕实验研究了涂层的力学性能,用动电位电化学方法测量镁合金及其涂层的腐蚀性能.研究表明:AM60镁合金表面等离子热喷涂TiO2涂层具有多孔的陶瓷结构,存在鳞片状和菜花状/珊瑚状2种形貌,涂层鳞片状部位氧含量要高于菜花状部位的氧含量,涂层的显微硬度的平均值为886 HV,划痕实验表明涂层与基体结合良好,封闭后的涂层明显地提高了镁合金在Hank's溶液中的耐蚀性能.     

需求信息更新下短生命周期产品的订货模型

短生命周期产品供应链的管理的核心问题，是零售商如何根据制造商提供的订货条件进行合理订货。根据一个产品生命周期市场需求信息更新，以及零售商和供应商如何制定有利于双方的第二次订货时间，和考虑库存成本的零售商在两次订货中怎样采用最优订货方式，对开始时刻和市场需求信息更新后的系统进行了建模和研究讨论，得到了两次订货条件下零售商应该采取的最佳订货量。     

网络词语的结构类型与构造方式

网络语言是使用于网络交际领域的一种颇具特色的语言形式。网络词语是网络语言的重要构成成分,其结构类型主要是复合法,如联合式,动宾式和偏正式。其构词方式主要有谐音、重叠、比喻、借代、字母缩写、音译借词和别解构词等。     

充液管道系统振动能量流研究

通过综述、归纳能量流的研究现状,从能量流的定义中分析影响和制约能量流的相关因数,说明了充液管道振动的原因,探讨了能量流的研究方法,指出了能量流研究的发展趋势.     

Effect of low temperature aging on microstructure and mechanical properties of super-high strength aluminum alloy

The effects of heat treatment on the microstructure and mechanical properties of two alloys, namely Al- 12.2%Zn-2.48%Cu-2.0%Mg-0.15%Zr-0. 166%Ag（alloy 1）, and Al-9.99%Zn-1.72%Cu-2.5%Mg-0.13%Zr（alloy 2） were investigated. The results show that low temperature aging after promotive solution treatment can increase elongation without the loss of strength for the studied alloys. The optimum aging treatment （T6） for alloy 1 and alloy 2 is 100 ℃/80 h and 100 ℃/48 h, respectively. Compared with other heat treatment alloys, alloy 1 and alloy 2 show super-high tensile strength up to 753 MPa and 788 MPa, remaining 9.3% and 9.7% elongation under T6 condition, respectively. During aging, trace addition of Ag enhances the formations of GP zone and metastable phase, and stabilizes GP zone and metastable phase to a higher temperature. Trace addition of Ag prolongs the aging time of reaching the peak strength and delays over-aging condition of the alloy. However, trace addition of Ag promotes the formation of coarse constituent in the alloy and consumes hardening alloying elements of Zn and Mg. Moreover, the addition of the transition element Zr in 7000 series super-high alloy forms incoherent Al3 Zr dispersoid which can serve as nucleation sites for nonuniform precipitation of η phase during aging process. The higher the aging temperature, the greater the tendency for nonuniform precipitation of η phase.     

Optimization of extraction and determination of emodin from Polygonum cuspidatum Sieb. et Zucc. products by HPLC-DAD

A uniform experimental design procedure was used to investigate the effects of some operating parameters on the extraction of emodin from Polygonum cuspidatum Sieb. et Zucc. products. Variables tested were volume ratio of material to solvent, size of material, extraction time and temperature and composition of extraction solvent （mixtures of acetone-water）. Each variable was tested at seven levels; 7 experiments were performed in random order. Analyses of the extracts were performed by high-performance liquid chromatography with diode array detection（HPLC-DAD）. Analytical responses were processed by using a forward regression analysis, in order to find polynomial function describing the relationship between variables and responses. For all the analytes the experimental conditions for providing the highest extraction yield inside the experimental domain considered were found. Finally, a simple, rapid and accurate analytical method was developed for the determination of emodin by high performance liquid chromatography. The separation is achieved within 25 rain on an ODS column using methanol and water as gradient mobiles. Emodin can be quantified by using external standard method detecting at 436 nm. Good linearity is obtained with correlation coefficient exceeding 0.9986 and the detection limit and the quantification limit are 1.53 and 3.23 mg/L respectively. This method shows good reproducibility for the quantification of the emodin with intra-day and inter-day relative standard deviation less than 2.3% and 5.6% respectively. Under optimized extraction conditions, the recovery of the standard is 96.5%. The validated method is successfully applied to quantify the emodin in seven Polygonum cuspidatum sieb. Et zucc. products, which provided an idea for the pre-treatment of determination of active compounds in traditional Chinese medicines.     

Preparation and characterization of polyimide/silica hybrid films

Polyimide (PI) thatserves as a typical kind of en-gineering polymer material has been used widely in aer-ial, nuclear and microelectronic industries because ofits outstanding characteristics, such as excellent ther-mal stability, relatively high tensile strength and modu-lus and, especially, preeminentelectrical properties in-cluding low dielectric constant[1]. But the pure poly-imide also has many disadvantages, such as high wetta-bility, thermal expansivity and poor corona-resistance.Moreove…     

发达国家职业技术教育理念的启示

职业技术教育在发达国家很受重视。从发达国家职业技术教育理念中我们得到的启示是:将人文素质教育贯穿职业技术教育的始终,使受教育者增强社会交往和与他人沟通、合作的能力,注重创新能力的培养,注重培养学生的实践能力和个性特长;以就业为导向;受教育者的需求被作为职业技术教育的主导内容。应借鉴国外先进经验,积极发展我国职业技术教育,尽快使我国职业技术教育纳入国际化轨道。     

现代温室的单片机控制系统

开发了一套与我国温室生产现状相适应的温室自动控制系统.系统下位机软件用汇编语言编程,采用结构化的编程方法,主要由数据采集模块,信号处理模块,输出控制模块,串口通讯模块组成.系统功能独立,其中下位机既可单独运行控制,也可通过串口由PC机进行监控.