Effects of E2 and El-E2 Interference on Coulomb Dissociation of 19C

We investigate the effects of higher order multipole transitions, in particular electric quadrupole （E2） and El-E2 interference, on the Coulomb dissociation of 19 C within the framework of the first order eikonal approximation. The sensitivity of the total Coulomb breakup cross section and the longitudinal momentum distribution of the core fragment to these effects are checked. The breakup occurs predominately through the dipole transition and the contribution of E2 transition to the total cross section is found to be within the range from 1 to 3% of that of El. It is further observed that the El-E2 interference term contributes nothing to the integrated cross section. On the other hand, the longitudinal momentum distribution is observed to be insensitive to the E2 transition while the El-E2 interference introduces a small asymmetry in its shape.     

Information-Disturbance Tradeoff in Estimating the Unknown Three-Qubit GHZ State

In a recent paper, Sacchi （Phys. Rev. Lett. 96 （2006） 220502） studied the information-disturbance tradeoff in estimating an unknown two-qubit maximally entangled state. In this study, we explore the tradeoff in estimating 13 an unknown three-qubit GHZ state. The optimal estimation process supplies a fidelity of 13/54 and the tradeoff interpolates smoothly between non-informative measurement and optimal estimation process.     

光电信息技术与信息化战争第九讲信息战的局限性(续)

信息时代的战争是信息化的战争，使用现代信息技术和装备进行的旨在夺取制信息权的信息战已成为信息化战争的一个重要作战样式。现在，任何战争都离不开信息战的加盟。按动侦察与干扰装置的开关就如同以往传统战争中抠动步枪和火炮的扳机一样那么自然和平常。     

数学选择题求解中的功亏一篑

虽然高考的改革在深入地进行,各科试卷的题型也在变化,但数学选择题以其"短、快、灵"的特点,仍然占据重要的一席之地.具有举足轻重的作用,尤其是命题者为了提高试题的区分度,常会在选择题上下功夫,这是因为数学选择题的选择支可以说是一把"双刃剑",一方面它具有一定的提示作用,另一方面它也具有干扰作用,它能导致数学素养低的学生解题中发生"为山九仞,功亏一篑"的现象,这也常令考生扼腕叹息,懊恼不己,这是怎么回事呢?本文试举例说明.……     

恒等式助你成功

<正>1.引入如果ax~2+bz+c=0是关于x的恒等式,求证:a=b=c.分析所谓ax~2+bz+c=0是关于x的恒等式,就是说对于任意实数x,这个等式总成     

椭圆的第一定义及标准方程复习

<正>我们在数学学习过程中,要注意对基本概念、常用基础知识点理解、概括与总结,进而能够熟练的运用,本文以椭圆的第一定义及标准方程为例作一小结,以期对同学们的学习有所帮助。     

构造常数列求解通项问题

<正>用递推关系式求数列的通项公式,是高中学生们的一个难点,也是高中阶段的一个重点内容.运用转化的思想,把所求数列的递推关系式转化为我们所熟悉的"等差数列"型或"等比数列"型,然后用相应的方法求出其通项公式.常见的方法有"累加法"(知道差式)和"累乘法"(知道商式)等等.这里我选用一教师教案中的三个例题,向同学们介绍一条新的思考途径——构常数列求通项公式.为对比起见,先写出该教师在那节课对三例所讲解的方法.     

THE GENERALIZED RIEMANN PROBLEM FOR A SCALAR COMBUSTION MODEL --THE PERTURBATION ON INITIAL BINDING ENERGY

In this paper, we study the generalized Riemann problem for a scalar Chapman-Jouguet combustion model in a neighborhood of the origin on upper half of the （x, t）plane. We focus our attention on the perturbation on initial binding energy. Under the entropy conditions, the solutions are obtained constructively. It shows that the perturbed Riemann solutions possess the structural stability except the case that the corresponding Riemann solutions contain CJDT, for which CJDT may transform into SDT after perturbation on initial binding energy in the neighborhood of the origin.     

一类带有Holling Ⅱ类功能性反应和相互干扰及脉冲效应的捕食系统

A kind of predator-prey system of Holling typeⅡand interaction perturbation with impulsive effect is presented.By using Floquet theory and small amplitude perturbations skills,the locally asymptotical stability of prey-eradication periodic solution and the permanence of the system are discussed and the corresponding threshold conditions are given respectively.Finally,the existence of positive periodic solution is investigated by the bifurcation theory.