DSP技术在声强测试系统中的应用

根据声强测试过程中对数据处理系统的需求,提出了以数字信号处理器(DSP)TMS320C5409与A/D转换器芯片MAX125为核心构建高速多通道声强数据采集处理系统的方案,并结合它们的特点对该方案进行了论证.同时,详细介绍了TMS320C5409与MAX125之间的硬件接口电路的设计和软件编程的方法.实验表明,该数据采集处理系统具有速度快、可靠性高、结构简单等特点,满足声强测试过程的技术要求.     

Tb3+,Mn2+作为激活剂的PDP绿色荧光粉的研究

分别介绍了以Mn^2＋和Tb^3＋作为激活中心的PDP用硅酸盐体系、铝酸盐体系、硼酸盐体系和磷酸盐等体系绿色荧光粉的研究现状。在以Mn^2＋作为发光中心的绿粉中，目前研究主要集中在通过调整Mn^2＋的离子浓度、添加其他杂质，探索使用新的基质材料，或是使用不同的合成技术等方法来改进其余辉时间过长、易时效劣化以及形貌上的不足。在以Tb^3＋作为激活中心的绿粉中，为了获取在真空紫外激发条件下高的发光效率，则主要围绕寻找在VUV区域内有强吸收的基质和能够有效进行能量传递的稀土敏化剂，以及利用量子剪裁效应来使得荧光粉发光量子效率大于1等方面进行。     

Time dependent crystal-smectic transformation in perylene-containing polyimides

The crystalline conformations of perylene polyimides (PPIs), with alkyl spacers varying in length from C₃ to C₁₂ are discussed. Although modeling of single chains would suggest the possibility that those with odd number of CH₂ groups adopt a flat helical shape, X-ray diffraction suggests that the chains with odd and even spacers have the same conformation, due to the necessity to pack the perylene units. Upon annealing, the UV-vis absorption maximum red-shifts by about 10 nm, indicating enhanced π-stacking between the perylenes. Several changes in the spectra are seen with an increase in annealing time, at a given temperature. With an increase in annealing time, X-ray diffraction patterns show changes in the number of reflections, indicative of a crystal to mesogenic transition. The time required for this transition increases with a decrease in the spacer length, and annealing temperature, suggesting that the dynamics of this transition is very slow.     

Synthesis of TiO<Subscript>2</Subscript> Hybrid Molecular Imprinted Polymer for Ethofumesate Linked by Silane Coupling Agent

TiO₂ hybrid molecular imprinted polymer (MIP) for ethofumesate using methacrylic acid (MAA) as the functional monomer and silane coupling agent 3-(trimethoxysilyl) propylmethacrylate (KH570) as organic–inorganic connective bridge was synthesized via photo-excitation method. Hydrogen bond was proved to act between MAA and ethofumesate for pre- and post-polymerization binding properties as testified by UV spectrometric method. KH570 modified TiO₂ nanoparticles were prepared via sonochemical reaction, which can accelerate hydrolysis, increase collision chance for the reactive system and improve the dispersion of the nanoparticles. Scanning electron microscope (SEM), transmission electron microscope (TEM), binding and the adsorption kinetics experiments as well as thermogravimetric analysis (TGA) were employed for characterization. The results indicated that the hybrid MIP revealed a larger surface area and more ordered imprinting cavities with improved thermal stability compared to organic-only MIP. Furthermore, faster adsorption kinetics and enhancive adsorption capacity were achieved, which made it promising in chemical sensor applications.     

Behaviors of concrete-filled steel tubular members subjected to combined loading

The present study is an investigation on the behaviors of concrete-filled thin-walled steel tubular members subjected to combined loading, such as compression and torsion, bending and torsion, compression, bending and torsion. ABAQUS software is used in this paper for the finite element analysis (FEA). A comparison of results calculated using this modeling shows generally good agreement with test results. The FEA modeling is then used to investigate the influence of important parameters that determine the ultimate strength of the composite members under combined loading, such as compression and torsion, bending and torsion, compression, bending and torsion. The parametric studies provide information for the development of formulae for calculating the ultimate strength of the composite members subjected to combined loading.     

海底管道系统失效故障树的建立及定性分析

受自然环境、管道腐蚀、第三方破坏及管理不善等因素的影响,海底管道系统在铺设及运行过程中常常会失效。文中以海底管道穿孔、凝管、断裂和设备故障等主要失效形式为顶事件建立了海底管道系统失效故障树,通过系统的定性分析得到了海底管道系统失效故障树的37个一阶最小割集,进而确定了影响海底管道系统失效的4项主要因素,并针对这些主要因素提出了相应的解决问题的措施。     

One-to-Many and Many-to-One Optical Chaos Communications Using Semiconductor Lasers

A theoretical construction of one-to-many (OTM) and many-to-one (MTO) chaos synchronization communications using semiconductor lasers is presented. One center laser provides strong injections (strong link) to other side lasers, and the side lasers also provide weak injections (weak link) to the center one. Simulation results show that the side lasers synchronize with the center laser through injection-locking. In addition, messages transmitted via the strong links or the weak links experience strong chaos pass filtering, enabling us to realize OTM and MTO communications.     

聚合物基金属梯度复合材料的制备与结构研究

本文通过石墨阴极溶液涂膜法制得甲基丙烯酸-丙烯酸共聚物[P(MMA-co-MAA)]与环氧乙烷(PEO)的共混聚合物,并以其为基质制备了聚合物基铜金属复合膜(CPCFs).在这一过程中,对所得溶胀阴极膜(SCF)进行半干燥处理后,用电化学方法使其还原以得最终产物.实验研究表明:(1)低P(MMA-co-MAA)含量会增强SCF的离子电导率;(2)还原反应中酸性环境会增强电导性;(3)水-乙醇共溶剂有助于增强电导率.偏光显微镜测试显示:poly(MMA-co-MAA)会影响PEO的结晶.X-射线衍射实验也证实了还原铜金属单质的存在.