Particle Transport with Asymmetric Unbiased Forces and Entropic Barrier

Transport of a Brownian particle moving along the axis of a three-dimensional （313） symmetric and periodic tube is investigated in the presence of asymmetric unbiased forces. It is found that in the presence of entropic barrier, the asymmetry of the unbiased forces is a way of inducing a net particle current. The particle current is a peaked function of temperature, which indicates that the thermal noise may facilitate the transport even in the presence of entropic barrier. There exists an optimized radius at the bottleneck at which the particle current takes its maximum value. The current can be influenced by the slope of tube walls and there exists an optimized slope for which the particle current takes its maximum value.     

Polymer White-Light-Emitting Diodes with High Work Function Cathode Based on a Novel Phosphorescent Chelating Copolymer

Polymer white-light-emitting diodes are fabricated based on the blend of poly[9,9-di-（2-ethylhexyl）-fluorenyl-2, 7- diyl]-end capped with polysilsesquioxane （PFO） and a chelating copolymer of poly[（9,9-bis（3′-（N,N-dimethylamino） propyl）-2, 7-fluorene-alt-2, 7-（9,9-dioctylfluorene） ）-co- [2, 7-（9,9-dioctlyfluorene）-alt-5,5-bis（2-（4-methyl-l-naphtha- lene） pyridine-C^2,N） iridium （III） acethylacetonate]] （PFN-NaIr）. The device with the sole aluminium cathode is able to produce a comparably white electroluminescence efficiency of 1.31 cd/A to that of the device using low work function cathodes （such as Ba, Ca, etc.）. The CIE coordinates of the white light emission consisting of red, green and blue three components are nearly at （0.34, 0.35）. The mechanism of the white light emission from the device with the AI cathode is investigated, which is related to the efficient injection of electrons through the interface of PFN-Nalr/AI.     

电容器放电的演示

这个演示可以说明电容器的几个基本性能,使得这些性能有趣和可信。应该特别指出电容器本来就是一个把电介质放在金属板间做成的。以静电场形式储存能量的系统。     

緃波演示实驗的改进

高中物理課本第二册第24頁图15及师范学校物理学(試用本)第一册第182頁图8—20,都載有关于纵波的演示装置图,同时都指出用手推拉弹簧的一端,会看到密部和疏部沿弹簧向另一端移动。这个实驗实际做起来有困难,效果也不好。在实践中我們曾改进了它,現将改进后的装置和做法介紹出来,以供参考。用直径d为0.65毫米的铁絲,繞成直径D約为5厘米、螺距/約为0.4厘米、长L約为60厘米的弹簧(繞制时,可先繞在一个腊紙筒上,然后取下,再在弹簧某端的一环中交連上三条鉄絲)。繞妥后用棉綫把弹簧悬掛在一根横杆上,大約每隔6厘米掛一根綫,全部装置如图所     

铵光卤石气固反应法制备无水氯化镁

铵光卤石气固反应法制备无水氯化镁;ouig     

Comments on Three-point explicit compact difference scheme with arbitrary order of accuracy and its application in CFD

The explicit compact difference scheme,proposed in Three-point explicit compact difference scheme with arbitrary order of accuracy and its application in CFD by Lin et al.,published in Applied Mathematics and Mechanics (English Edition),2007,28(7),943-953,has the same performance as the conventional finite difference schemes.It is just another expression of the conventional finite difference schemes. The proposed expression does not have the advantages of a compact difference scheme. Nonetheless,we can more easily obtain and implement compared with the conventional expression in which the coefficients can only be obtained by solving equations,especially for higher accurate schemes.     

改进的假高稀技术合成聚苯胺三聚体和四聚体及其紫外光 …

提出了一条合成还原态的苯基封端聚苯胺齐聚物的新方法：即苯胺二聚体的Ｓｃｈｉｆｆ碱或苯胺三聚体的Ｓｃｈｉｆｆ碱的酸性溶液中缓慢水解,形成聚苯胺二聚体和三聚体的盐酸盐,这些盐酸与二苯胺或Ｎ－苯基－对苯二胺反应,经苯肼还原,生成还原态的苯基封 聚苯胺三聚体和四聚体。用红外、核磁、元素分析和基底辅助激光解吸质谱对其进行了表征,并用紫外光谱对还原态的三聚体和四聚体化学氧化过程进行敢跟踪研究。     

基于严格耦合波理论的蝴蝶鳞翅分级结构光学特性研究

Morpho蝴蝶的颜色效应是由蝴蝶鳞翅上特殊的分级微纳结构与光发生干涉、衍射和散射等作用引起的,是一种典型的结构色.以严格耦合波理论(RCWA)为基础,借助光学衍射结构综合设计工具,建立了仿蝴蝶鳞翅分级结构的二维模型,系统分析了底层电介质单元横向周期占空比、纵向相邻电介质单元宽度差值、介质层纵向周期占空比以及脊柱与基底...     

高地应力条件下隧洞开挖动态卸荷的破坏机理初探

分析了高地应力条件下静水压力场中圆形隧洞钻爆开挖时开挖边界上初始应力场动态卸荷效应及破坏机理，并计算了其破坏范围。初始应力动态卸荷时，动应力在隧洞径向表现为卸荷回弹，而在切向出现动应力集中，表现为加载。动态卸荷时间对径向应力的影响较对切向应力大，卸荷时间越短，扰动的幅度越大；初始应力动态卸荷在岩体中所造成的破坏范围较准静态卸荷情况大，卸荷时间越短，破坏范围越大。