一枝一叶总关情     

邹伟宏 《小雪花(小学生成长指南)》2011,(3):4-6

华章溢彩 紫藤萝瀑布（节选） 宗璞 但是我没有摘。我没有摘花的习惯。我只是伫立凝望,觉得这一条紫藤萝瀑布不只在我眼前,也在我心上缓缓流过。流着流着,它带走了这些时一直压在我心上的焦虑和悲痛,那是关于生死谜、手足情的。  相似文献   

WPT-based modal control on distributed structures with MRF-04K damper     

林伟  李忠献  张根明  黄鹏云 《天津大学学报(英文版)》2011,17(6):397-403

The magnetorheological (MR) fluid damper-based semiactive control systems have received considerable attention for protecting structures against natural hazards such as strong earthquakes and high winds. In this paper, a novel modal controller using wavelet packet transform (WPT) is proposed for the vibration control of distributed structures. In the proposed control system, the WPT method is utilized to decompose the acceleration measurement and select the modes containing most of the WPT energy component as the dominant modes. Then, a modal controller is designed to control the dominant modes and the optimal active control force is solved. Finally, Clipped-optimal con- trol law is adopted to determine the voltage applied to each MR damper. A Kalman-filter observer, which estimates the full controlled modal states from local accelerometer feedbacks, is designed for rendering the controller to be more applicable to distributed structures with a large number of degrees of freedom. A numerical example of a stadium roof structure installed with MRF-04K damper is presented. The effectiveness of the controller is evaluated under both Tianjin and El Centro earthquake excitations. The superior performance and adaptability of the controller for versatile loading conditions are demonstrated through the comparison with traditional truncated modal controller.  相似文献   

基于谱减的双元指向传声器阵列语音增强     

廖逢钗  卢昌荆 《南平师专学报》2011,30(2):73-76

设计了一种结构简单的用于语音增强的双元指向性传声器阵列,利用阵列中不同方位阵元对目标信号和干扰信号的增益不同的特点,有效估计噪声信号的功率谱,再利用传统谱减算法的思想,实现语音增强。实验结果表明提出的算法是有效的,与经典的谱减算法相比具有更佳的语音增强效果。  相似文献   

一类广义积分的计算方法     

黄朝军 《凯里学院学报》2006,24(3):1-2

对于广义积分integral from n=0 to ∞ dm/dx~m(1/1 x~2)d~n/dx~n(1/1 x~2)dx和integral from n=0 to ∞ d~m/dx~m(sin x/x)d~n/dx~n(sin x/x)dx(m,n为非负整数),采用Fourier变换及级数计算出它们的值,并指出在区间(-∞, ∞)上可积的函数f(x),亦可仿此计算广义积分integral from n=0 to ∞ f~(m)(x)f~(n)(x)dx.  相似文献   

论同科电子P2组态的光谱项及光谱支项     

高文启  王英杰 《沈阳教育学院学报》2001,3(1):101-103

根据电子排布法按保里原理的要求，将给定的组态的电子分别排布在各可能的轨道上，然后在可能的电子排布的微观状态中找出M5的最大值（M5)max,以及与之相适应的（ML）max,根据这两个值找出S和L值，得出光谱项，再将ML和MS偶合，得到光谱支项。  相似文献   

力的相对论变换     

刘燕 《云南教育学院学报》1997,13(2):51-53

本文由四维力矢量的变换关系推出了力的相对论变换关系，并澄清了变换式中的γ因子的速度取向问题，指出教材的不足。  相似文献   

一个三维孤立子方程的Bcklund变换     

张海清  黄迅成 《扬州职业大学学报》2006,(1)

研究了一个三维的孤立子方程的Backlund变换(BT)和非线性叠加公式,证明了文[3,4]中的三维的Backlund变换可以分解成三个二维的Backlund变换,并讨论了一些与N维Liouville方程有关的问题。  相似文献   

联合变换相关识别三维物体     

王海霞  张星 《洛阳师范学院学报》2008,27(5)

将一正弦条纹分别投影到参考物体和待测物体表面,得到参考物体的变形条纹图像和待识别物体的变形条纹图像。以此变形条纹作为联合变化相关的输入图像,通过联合变换相关,得到自相关和互相关输出,最后根据输出的相关峰大小即可判别不同的物体。用Matlab软件编程实现三维物体联合变换相关识别,并且验证了联合变换相关识别物体具有平移不变性。  相似文献   

平面射影几何基本定理的一个等价命题     

肖辉成 《宜宾学院学报》1996,(2)

本文证明了平面射影几何基本定理的一个等价命题:即由不共线三对对应点及不过此三点的一对对应直线确定一个平面射影变换.  相似文献   

Computation of the Simplest Normal Forms for Resonant Double Hopf Bifurcations System Based on Lie Transform     

张琪昌何学军  郝淑英 《天津大学学报(英文版)》2006,12(3):180-185

The simplest normal form of resonant double Hopf bifurcation was studied based on Lie operator. The coefficients of the simplest normal forms of resonant double Hopf bifurcation and the nonlinear transformations in terms of the original system coefficients were given explicitly. The nonlinear transformations were used for reducing the lower- and higher-order normal forms, and the rank of system matrix was used to determine the coefficient of normal form which could be reduced. These make the gained normal form simpler than the traditional one. A general program was compiled with Mathematica. This program can compute the simplest normal form of resonant double Hopf bifurcation and the non-resonant form up to the 7th order.  相似文献