Eu3+和Tb3+的2,3-吡啶二甲酸配合物的发光研究

合成了一系列Eu3+和Tb3+与 2 ,3-吡啶二甲酸 (简称H2 QUI)的单核、同多核及它们分别与非荧光性稀土离子La3+,Gd3+,Y3+的异多核配合物 ,并对单核配合物分别引入含氮配体 1,10-邻菲咯啉 (简称 phen)和 2 ,2’ -联吡啶 (简称 2 ,2’ -bipy)生成三元配合物。对这些配合物进行了红外     

拉伸载荷下混凝土体分形内聚模型

在综合考虑混凝土试件损伤面分形分布及损伤面分形演化基础上,论文提出了体分形内聚模型,用于描述混凝土试件在准静态拉伸载荷作用下的破坏行为.数值计算结果与现有实验数据吻合较好.此外,采用该模型分析了混凝土骨料级配对材料软化性质的影响.结果表明,在拉伸载荷作用下,混凝土骨料级配越均匀,材料的软化特征越明显.     

次级声源优化布放的局部空间有源降噪

针对区域有源降噪问题,为获得更优降噪效果,根据实际次级通路传递函数,提出次级声源优化布放的有源控制系统并详细比较了两种次级声源优化布放算法与次级声源均匀布放的实际降噪效果。应用的第一种次级声源优化算法是l₂范数约束的约束匹配追踪算法,第二种次级声源优化算法是l₁范数约束的稀疏正则化方法。在全消声室中利用扬声器线阵进行多通道有源降噪实验研究,实验结果表明,在200～1000 Hz,次级声源优化布放的控制系统的平均降噪量比次级声源均匀布放的控制系统的平均降噪量多5 dB左右;在1100～1900 Hz,次级声源优化布放的控制系统的平均降噪量比次级声源均匀布放的控制系统的平均降噪量多11～13 dB左右,次级声源优化布放的控制系统的降噪量分布更加均匀且次级声源输出能量更小。此外,两种优化算法中,稀疏正则化方法的降噪效果更佳。     

球形粒子在聚焦拉盖尔-高斯光束中的散射特性研究

研究了球形粒子在聚焦拉盖尔-高斯光束中的散射特性. 根据广义Mie理论, 推导出球形粒子在聚焦拉盖尔-高斯光束中散射系数的解析公式. 针对光束的电场分布及粒子散射强度进行了数值仿真, 讨论了散射强度随散射角、散射球粒子半径和拓扑荷的变化特性, 并通过散射系数解释了散射强度分布的振荡现象. 结果表明, 在聚焦拉盖尔-高斯光束照射下, 球形粒子的后向散射强度随着粒子半径的增大而逐渐增大; 后向散射强度开始增大时对应的粒子半径与拓扑荷有关. 通过与高斯光束的对比, 可以看出球形粒子在聚焦拉盖尔-高斯光束中散射特性的差异, 使其在粒径测量、光通信和大气后向散射探测等方面具有潜在应用价值.     

振荡吸积盘的光变研究

理论研究指出随机振荡吸积盘可能引起活动天体的光变,然而观测数据分析表明光变中除了含有随机噪声外还存在混沌因素.将混沌因素引入到随机振荡吸积盘中,构成"混沌+随机"振荡吸积盘模型.通过分析扰动的相图,直观再现了混沌吸引子的状态.研究结果表明:在随机因素占主导时,光变混乱无序;随机因素与混沌因素相当时,光变上下起伏类似于心电图;混沌因素占主导时,光变具有一定有序性.模拟光变曲线的关联维与观测数据的关联维一致,表明模拟光变曲线与观测结果之间存在内在联系.     

Er3+:YAlO3/Fe或Co掺杂ZnO包覆物的制备及光催化活性研究

主要对ZnO半导体材料进行改性,分别通过溶胶凝胶、超声分散和溶液沸腾的方法合成了Er3+:YAlO3/Fe或Co掺杂ZnO复合物光催化剂,并且采用XRD和SEM进行表征,研究了各种因素在太阳光照射下降解酸性红B的催化活性,也考察了Er3+:YAlO3包覆量、Er3+:YA-lO3/Fe或Co掺杂ZnO、太阳光照射时间、处理温度和处理时间对降解率的影响,并通过HPLC进一步验证偶氮品红的降解程度。实验结果表明,加入上转换发光剂(Er3+:YAlO3占催化剂总量25%最好)之后降解率大幅度增加,改性后的光催化剂能有效地降解染料废水。     

A REDUCED FE FORMULATION BASED ON POD METHOD FOR HYPERBOLIC EQUATIONS

A proper orthogonal decomposition(POD) method was successfully used in the reduced-order modeling of complex systems.In this paper,we extend the applications of POD method,namely,apply POD method to a classical finite element(FE) formulation for second-order hyperbolic equations with real practical applied background,establish a reduced FE formulation with lower dimensions and high enough accuracy,and provide the error estimates between the reduced FE solutions and the classical FE solutions and the implementation of algorithm for solving reduced FE formulation so as to provide scientific theoretic basis for service applications.Some numerical examples illustrate the fact that the results of numerical computation are consistent with theoretical conclusions.Moreover,it is shown that the reduced FE formulation based on POD method is feasible and efficient for solving FE formulation for second-order hyperbolic equations.     

Performance of a two-state quantum engine improved by the superposition effect

The performance of a two-state quantum engine under different conditions is analyzed.It is shown that the efficiency of the quantum engine can be enhanced by superposing the eigenstates at the beginning of the cycle.By employing the finite-time movement of the potential wall,the power output of the quantum engine as well as the efficiency at the maximum power output(EMP) can be obtained.A generalized potential is adopted to describe a class of two-level quantum engines in a unified way.The results obtained show clearly that the performances of these engines depend on the external potential,the geometric configuration of the quantum engines,and the superposition effect.Moreover,it is found that the superposition effect will enlarge the optimally operating region of quantum engines.     

Periodic and subharmonic solutions for a class of non-autonomous Hamiltonian systems

Some existence theorems are obtained for periodic and subharmonic solutions of a class of non-autonomous Hamiltonian systems. Our technical approach is based on a version of the Local Linking Theorem, and the Generalized Mountain Pass Theorem.