Physical mechanism of the chaotic detection of the unknown frequency of weak harmonic signal and effects of damping ratio on the detection results

In the zero-order approximation, we use the perturbation method of parameter with small magnitude to prove that the harmonic frequency in the solution of the equation is close to that of the driving force when the chaotic system from Duffing－Holmes equation stays in the stable periodic state, which is the physical mechanism of the detection of the unknown frequency of weak harmonic signal using the chaotic theory. The result of the simulation experiment shows that the method proposed in this paper, by which one can determine the frequency of the stable system from the number of circulation change of the phase state directionally across a fixed phase state point (x,\dot{x}) in fixed simulation time period, is successful. Analyzing the effects of the damping ratio on the chaotic detection result, one can see that for different frequency ranges it is necessary to carefully choose corresponding damping ratio α.     

Synchronization between two different noise-perturbed chaotic systems with unknown parameters

In this paper, a general method of synchronizing noise-perturbed chaotic systems with unknown parameters is proposed. Based on the LaSalle-type invariance principle for stochastic differential equations and by employing a combination of feedback control and adaptive control, some sufficient conditions of chaos synchronization between these noise-perturbed systems with unknown parameters are established. The model used in the research is the chaotic system, but the method is also applicable to the hyperchaotic systems. Unified system and noise-perturbed RSssler system, hyperchaotic Chen system and nolse-perturbed hyperchaotic RSssler system are taken for illustrative examples to demonstrate this technique.[第一段]     

如何用Excel管理《化学教育》参考资料

本文介绍如何将资料输入Excel,以及如何利用Excel进行资料的查找。     

Quantum Standard Teleportation Based on the Generic Measurement Bases

We study the quantum standard teleportation based on the generic measurement bases. It is shown that the quantum standard teleportation does not depend on the explicit expression of the measurement bases. We have given the correspondence relation between the measurement performed by Alice and the unitary transformation performed by Bob. We also prove that the single particle unknown states and the two-particle unknown cat-like states can be exactly transmitted by means of the generic measurement bases and the correspondence unitary transformations.     

微机械加速度计自动测试系统

为了精确、高效地测量微机械加速度计的各项性能指标,并尽可能地降低地线干扰,系统采用DAQ-2213数据采集卡采集加速度计输出电压,使用多个独立电源及差模接法来降低地线干扰;温度敏感元件采用Pt100,电阻到电压变换电路采用三线制接法,选择PCI-(A)9114数据采集卡采集变换电路输出的电压值;采用Labview7.0接口函数实时显示加速度计输出电压和温度值,并输出有图表的Word文档.系统经过标定,输出电压精度为40 μV,温度精度为0.277℃.实验表明,系统能实时测量微机械加速度计的输出电压和温度值,而采用独立电源和差模输入可有效减少各路信号之间的干扰.     

Faithful Controlled Teleportation of an Arbitrary Unknown Two-Atom State via Special W-States and QED Cavity

A scheme is proposed for the controlled teleportation of an arbitrary two-atom state via special W-type entangled states and QED cavity. The scheme does not involve the direct joint Bell-state-measurement （BSM）. We show that the quantum information is split into two parts~ thus the original atomic state cannot be perfectly restored by the receiver without the other agent＇s collaboration and classical communication. In addition, the physical realization of this scheme is not difficult.     

未知纬度的捷联惯导系统晃动基座自对准方法

传统捷联惯导系统晃动基座对准方法中,一般要求提供当地准确的地理纬度信息,如果给定的纬度存在误差,会对初始对准精度造成影响.针对纬度未知情况下的晃动基座对准问题,提出了利用三个不同时刻的重力视运动向量的运算进行对准的方法,推导了三矢量定姿对准的基本原理.针对含有随机噪声的加速度计测量值构造的重力视运动向量会导致向量运算时出现共线向量的问题,设计了一种基于平均权重系数的自适应卡尔曼滤波器,能在未知动态环境下有效去除加速度计随机噪声,提高对准精度.仿真和试验结果表明,该方法可在纬度未知条件下完成捷联惯导系统晃动基座下的自对准并估计出纬度值,对准精度可达惯性器件误差所决定的对准极限精度.     

基于激光雷达观测的大气边界层自动识别局部最优点算法

大气边界层高度是影响近地面大气物理运动的主要因素,同时也是影响地面污染物浓度的一个重要因素。地基激光雷达可以对大气气溶胶的垂直分布进行连续稳定的监测,应用激光雷达技术对大气边界层进行连续观测可以为环境监测与预报提供指导性的动态信息。针对存在残留层以及外来污染物输入情况时边界层高度变化检测的可靠性及计算效率问题,结合梯度法的物理意义与激光雷达时序图的图形图像学特征,提出了一种基于时空邻近度的边界层局部最优点识别算法。以江苏省无锡市新区偏振米散射激光雷达太湖观测站点的气溶胶垂直观测数据为例,通过对2012年底两次污染事件进行观测分析,分别使用梯度法和局部最优点法进行大气边界层高度的自动识别。实验结果表明,在静稳状态和污染混入后的情况下,梯度法与局部最优点识别法的结果较为接近,但梯度法在处理污染混入状态以及存在残留层的情况下误判率较高。基于时空邻近度的局部最优点算法通过对垂直特征值以及水平相关性的控制,有效地消除了在弱信号、噪声信号、低云以及存在残留层和外来污染等情况下导致的计算机误判现象,在减小算法时间复杂度的同时在计算机自动识别结果具有更高的稳定性,弥补了梯度法在自动化运行中的识别精度与计算效率的不足。     

基于DEA改进前沿面的输入拥塞分析

输入拥塞分析为投入产出分析提供了另一种视角，即通过减少冗余输入以增加输出。当前，对生产单位进行输入拥塞分析的主要方法是基于数据包络分析(DEA)模型的BCSW模型。BCSW模型的基本思想是将被评价单位与DEA前沿面上的有效率单位进行比较从而得出输入拥塞的值。但该方法忽略了DEA前沿面的数据敏感性问题，即前沿面上单位发生极小变动会导致评价结果的巨大改变，导致分析结果缺乏稳健性。本文提出了一种启发式方法，从改进DEA前沿面的角度出发，通过在误差范围内找到最佳前沿面，使输入拥塞分析结果更加合理。方法的提出从DEA前沿面的数据敏感性问题的原因出发，利用最小二乘法基本思想确定DEA最佳前沿面所需具备的性质。之后在该性质下，利用超效率DEA模型的思想和方法，解决DEA前沿面存在的问题，确定了该启发式方法。最后，本文在该方法所确定的最佳前沿面的基础上，利用BCSW模型进行输入拥塞分析，在实例数据上取得了相对于原始BCSW模型更合理也更具解释性的结果，证实了利用输入拥塞分析时，DEA前沿面确实存在的问题以及解决该问题对输入拥塞分析方法的改进作用。     

测三级管特性的改进电路

指出了电子线路基础实施教材中所给出的测三级管特性的电路所存在的问题，提出了合理的.