由大学多媒体教学实践所引发的深入思考

多媒体技术是物理教学良好的辅助工具，多媒体技术的应用为大学物理教学开辟了一片广阔天地。它能大大增加物理教学的信息量，图形形象直观、生动活泼，有着传统教学无法比拟的优势，但是，多媒体技术使用不当也会给物理教学带来一些负面影响。     

A Convenient Synthetic Method of Metal Dendritic Porphyrins

Metal porphyrins are natural antioxidant reagent1-3. However, due to the characteristics of structures, they are only soluble in inorganic acids and part of polar organic solvents. Thus, it is limited to be used as effective pharmaceutical preparations. T…     

High longitudinal selectivity of shifting multiplexing in volume holograms

High longitudinal selectivity of the shifting multiplexing with spherical reference wave is proposed and demonstrated. A simplified method based on wave optics is used for calculating the selectivity, and the result fits well the experimental measurement. Under the paraxial condition, a simple formula for the longitudinal selectivity is introduced. With use of an object lens with effective NA=0.817, we obtain that an FWHM of selectivity is as small as 1 μm.     

机械式光开关市场定位及需求

简述了传统机械式光开关的现状 ,并从工作原理、结构及加工工艺等方面给出了其性能、零部件外型体积及光学指标 ;分析了传统机械式光开关的市场定位、市场需求以及它在当前光网络中的应用。     

最有效的相容剂是两嵌段还是多嵌段聚合物？

采用Monte Carlo模拟方法研究了多嵌段聚合物在A／B／嵌段聚合物三组份体系作为相容剂使用的有效性．占总体积19％的A组份在体系中为分散相．模拟结果显示了两嵌段和多嵌段聚合物在界面上的聚集行为,以及如何影响这个不相容体系的相形为．两嵌段聚合物趋于直立在相界面上,而多嵌段聚合物更容易横跨在相界面上并占据较大的界面积．从而导致多嵌段聚合物更有效的阻止体系相分离的发生．     

ATM网络中CBR业务连接允许控制机制

该文提出了一种基于有限容量缓冲区下CBR业务信元丢失率和最小速率替换的线性近似连接允许控制机制，与原有的CAC机制相比，该文的CAC机制存在两个方面的改进：一方面，使用更合理、精确的CLR表达式，从而能够作出更为准确的连接允许判断：另一方面，能够提供服务质量服务。     

现场拉曼光谱研究乙腈在金电极上的解离吸附行为

利用共焦显微拉曼系统、结合合适的电极表面粗糙方法研究了非水体系 0 1mol/LLiClO4 /CH3CN溶液中 ,乙腈分子在金表面的吸附和解离行为。结果表明非水体系中乙腈可在金表面发生还原反应 ,产物CN- 离子与电极表面作用形成的表面配合物可在较宽的电位区间吸附于电极表面。溶液中的微量水、激光照射以及电极电位均对该反应有较大的影响。通过拉曼谱图的比较得出乙腈分子解离出的CN- 在金电极表面比在银电极表面有更强的吸附作用。     

A Lower Bound for {a+b:aA, bB, and P(a,b)≠0}

Let A and B be two finite subsets of a field . In this paper, we provide a non-trivial lower bound for {a+b:aA, bB, and P(a,b)≠0} where P(x,y) [x,y].     

垂直腔激光器中弛豫振荡频率的优化控制

从垂直腔面发射的半导体激光器（VCSELs）的结构出发，利用增益与载流子密度的广义对数关系，借助小信号分析法，推出了直接调制情形下驰豫振荡频率的严格解析关系。分析指出，量子阱器件的光子寿命并非越短越好，欲提高VCSELs的驰豫振荡频率，除了增加注入电流，提高微分增益等基本途径外，控制器件的结构参数可使驰豫振荡频率达到极大值。同时，自发辐射因子的可控性，以及降低稳态载流子密度，也都是提高VCSELs驰豫振荡频率和拓宽调制带宽的有效措施。     

Acoustic vector sensor signal processing

Acoustic vector sensor simultaneously, colocately and directly measures orthogonal components of particle velocity as well as pressure at single point in acoustic field so that is possible to improve performance of traditional underwater acoustic measurement devices or detection systems and extends new ideas for solving practical underwater acoustic engineering problems. Although acoustic vector sensor history of appearing in underwater acoustic area is no long, but with huge and potential military demands, acoustic vector sensor has strong development trend in last decade, it is evolving into a one of important underwater acoustic technology. Under this background, we try to review recent progress in study on acoustic vector sensor signal processing, such as signal detection, DOA estimation, beamforming, and so on.