基于进化算法的多目标优化方法

进化算法在解决多目标优化问题中有其特有的优势.首先对多目标优化问题进行了描述;然后结合研究现状讨论了目前几种主要的基于进化算法的多目标优化方法,以及它们的优缺点;最后给出了多目标进化优化算法的一些应用,以及进化多目标优化算法的未来发展方向.     

无线局域网的安全性与改进方法研究

论文介绍了无线局域网安全协议的基本原理,分析了主要安全协议存在的缺陷并在此基础上提出了几种增强WLAN安全的方案。     

互质因子摄动系统最优l1鲁棒控制:连续性与自适应控制

针对具有互质因子摄动和未知干扰的离散时间系统研究了一种自适应鲁棒控制策略. 本文的主要工作包括三个方面.首先建立了互质因子摄动系统最优l1鲁棒控制设计的连续性. 然后,提出了一种带变死区的参数鲁棒估计投影算法.最后,结合所提出的参数估计算法和最优 l1鲁棒控制,利用确定性等价原理提出了互质因子摄动系统的一种新的自适应鲁棒控制方法.基 于本文建立的l1优化设计的连续性,证明了自适应鲁棒控制的全局稳定性,给出了自适应控制系 统稳定性的后验可计算条件.     

Unix上基于事务的中间件(VP)的时钟管理方案

详细地阐述了VP的时钟管理方案的原理和具体实现，从算法的时间和空间的开销角度对该时钟管理方案进行了分析，从而表明该方案能够较好地解决VP的时钟管理问题。该时钟管理方案的突出特点是：巧妙地将物理时钟算法和向量逻辑时钟算法融合在一起，相辅相成，而且采用HOT—STANDBY设计思想提高了时钟管理的系统可靠性。     

异步起动钕铁硼永磁同步电动机的设计研究

在讨论了异步起动钕铁硼永磁同步电动机设计特点基础上，编制了该种电机设计软件，设计与试制了Nd-FeB永磁同步电动机，同时也提出了该种电机的合理应用场合。     

基于PLC和变频器串行通讯的变频恒压供水系统

介绍了一种基于PLC和变频器采用串行总线方式通讯的变频恒压供水系统的构成和工作原理。系统采用变频调速方式自动调节水泵电机转速，保持供水压力的恒定，在用水低谷时投入小流量泵，降低电能损耗。变频器故障时仍能自动运行．保证不间断供水，同时故障消除后能自启动，实现无人值守全自动运行。     

在役电站锅炉导汽管组织状态评估与剩余寿命预测

对某热电厂已运行108835h的锅炉导汽管组织状态和力学性能进行了试验分析。金相分析表明，在役的导汽管材料组织中，珠光体已经完全球化，但材料的常温力学性能仍符合标准。通过对持久温度试验数据的线性拟合与平行外推，预测其剩余寿命至少仍有70000h。     

SiO2平面光波导工艺中的反应离子刻蚀研究

利用反应离子刻蚀工艺实现硅基SiO2平面光波导的刻蚀,研究了不同刻蚀条件对刻蚀速率、刻蚀选择比、刻蚀侧壁光洁度等刻蚀结果的影响,并首次研究了分别以无定形硅与多晶硅作为SiO2波导刻蚀掩膜对刻蚀垂直度的影响.利用改进的SiO2反应离子刻蚀工艺,得到了传输损耗极低的SiO2光波导.     

In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds

To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissue engineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, I.e. Solvent casting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behavior of the porous scaffold, e.g. Weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP, the particle size ofβ-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporated into the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold were determined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Results show that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strength needed for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility and osteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation and osteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It is expected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.     

Determination of Myricetin in Medicinal Plants by High-Performance Liquid Chromatography

The concentrations of myricetin in medicinal plants such as <i>Rosa canina</i> L. (rosa hip), <i>Terebinthina chica</i> L. (terebinth), <i>Urtica dioica</i> L. (nettle), and <i>Portuca oleracea</i> L. (purslane) were determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The aglycones of myricetin were extracted using methanol–ascorbic acid– hydrochloric acid, methanol–hydrochloric acid, and methanol, separated within 5 min, and individually quantitated in the positive ionization mode using optimized conditions for HPLC-MS. Methanol–ascorbic acid–hydrochloric acid was the optimum extraction solvent. The myricetin concentration in the plants were between 3 and 58 mg kg<sup>?1</sup>, with a limit of quantification equal to 0.1 mg L<sup>?1.</sup>