等比数列一个“性质”的修正

《中学生数学》2001年第11(月上)期“等比数列的性质及其应用”一文,列举了等比数列的10个性质,其中的性质5是这样的:若{an}是等比数列,公比为q,则sum fromi=1 to k ai,sum fromi=k 1 to 2k ai,sum from i=2k 1 to 3k ai,…仍成等比数列,其公比为qk. 其实,这个“性质”是有问题的,因为sum fromi=1 to k ai,sum fromi=k 1 to 2k ai,sum from i=2k 1 to 3k ai,…是否成等比数列,与q和k的取值情况有关. 显然,当q=-1,且k为正偶数时,sum fromi=1 to k ai     

用自适应脉冲微扰引导混沌系统到周期解

用自适应脉冲微扰方法控制的系统的某个系统变量作为驱动,设计了一种自适应控制器方法对两个或多个响应混沌系统进行脉冲微扰,引导这些系统从混沌运动到低周期运动,实现同时控制多个混沌系统到不同的周期态. 当选择相同的自适应控制器输入变量实施脉冲微扰时,还可控制两个或多个混沌系统达到不同的周期态同步. 通过对R?ssler混沌系统的仿真研究证实了方法的有效性. 关键词： 混沌控制 系统参量 自适应控制器 脉冲微扰 周期态同步     

高纯度烟草过氧化物酶(TOPⅠ)光谱特性研究

采用交换吸附脱色及柱层析新技术,成功地从烟叶中分离和纯化了一种烟草过氧化物酶同工酶(TOPⅠ),并对其进行了一系列光谱特性研究.基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)测得TOPⅠ分子量为21 888.5,等电点pI为3.5;氨基酸组成分析表明TOPⅠ为一含血红素的酸性蛋白酶.光谱学分析揭示,在402 nm处有一典型的Soret带,在498和636 nm处有特征吸收峰(α,β带),酸度和变性剂对TOPI在紫外可见区的特征吸收峰均产生一定的影响,TOP Ⅰ的荧光光谱测定结果说明TOPⅠ分子中含有Trp残基和Tyr残基以及其自身的独特的光谱学特性.     

OADM环网的实验研究

研究了光分插复用器(OADM)的关键技术,重点分析了相关的实现技术,完成了利用OADM构建全光环网的实验研究,给出了重要的实验数据,包括眼图、光谱图、光信噪比、保护与恢复等,并对这些实验数据进行了分析,为光传送网的设计与构建提供了重要的参考依据.     

Generation of UV laser light by stimulated Raman scattering in D2, D2/Ar and D2/He using a pulsed Nd:YAG laser at 355nm

A pulsed Nd:YAG laser at 355nm is used to pump Raman cell filled with D_2, D_2/Ar and D_2/He. With adequately adjusted parameters, the maximum photon conversion efficiency of the first-order Stokes light (S_1, 396.796nm) reaches 33.33% in D_2/Ar and the stability of S_1 in pure D_2 is fairly high, the energy drift being less than 10% when the pump energy drifts in the range of 5%. The conversion efficiency and stability, which are functions of the composition and pressure of the Raman medium and the energy of pump laser, are investigated. The result has been used to optimize the laser transmitter system for a differential absorption lidar system to measure NO_2 concentration profiles.     

合作联盟资源集成计划一种新方法

合作联盟里，资源集成计划往往是联盟成员群体谈判博弈的结果。本以两人博弈为例，对联盟的资源集成计划给出一个谈判博弈模型，能够较好地模仿和反映合作联盟资源整合计划的制订过程。     

MgB2交流响应teff的电流效应

本文并从磁通守恒方程出发,详细求导了Slab样品(厚度为d)交流磁化率的测量方程,并以MgB2为例,测量了在不同外场H和交流信号的频率γ交流磁化率,求得Ueff和J的关系实际上是满足Zeldov关系,实验结果和理论假设完全自洽.     

Gain Spectrum in an Asymmetric Double Quantum Well

We propose a scheme for light amplification in an asymmetric double quantum well, where two excited states are coupled by resonant tunnelling through a thin barrier in a three-level system of electronic subbands. By applying a single driving laser, the steady state gain can be obtained. The calculated gain spectrum for an asymmetric GaAs/AlGaAs double quantum well structure was presented.     

一种新型的二元光学器件——多位相光束分束器的制作

本文报道了用于多光束分束器的反射式16位相值二元光学器件的制作。该二元光学器件把一束光束分成5×5光束阵列。测量的衍射效率为76.16%,接近理论设计值79.68%。该二元光学器件的有效孔径为10mm×10mm。     

Quantum State Transfer between Two Distant Atoms by Connecting Two Cavities via Optical Fibres

A scheme is proposed to unconditionally implement state transfer between two distant atoms by sending the atoms across two distant cavities connected via an optical fibre, respectively. The field state, which preserves the information about the first atom, is transmitted from one cavity to the other along the fibre. A Faraday rotator integrated in the fibre can be designed to completely stop the fields reflected from the second cavity, thus after the field interacts with the second atom for a defined time, the state transfer can be accomplished with unit efficiency.