查询词典 periodic function

In order to develop this local property,this paper presents a method,which uses Fourier Series to approximate the boundary shapes of the shafts with periodic boundary of cross section,and uses the conformal mapping in Theory of Function of a Complex Variable to make the complicated boundary shapes of the shafts map a unit circle.Thus elastic theory can analyze...

本文提出一种方法，其实质是：采用富里埃级数来逼近横截面呈周期性变化边界的轴类零件的边界形状；并应用复变函数论中保角映射原理，将零件复杂的边界形状映像成单位圆，从而使弹性理论可以分析和计算复杂边界轴类零件的应力场；再通过留数的求解实现保角映射的反变换。

In this dissertation, digital lock-in detection techniques under integer period sampling and non-integer period sampling are separately investigated (1) Under integer period sampling, digital signal sequence is acquired through sampling the measured signal, but digital reference sequence is acquired through mathematical operation, then digital lock-in detection can be realized by calculating crosscorrelation function of digital signal sequence and digital reference sequence Harmonic measure is also analyzed, and a method of measuring harmonic of a periodic signal under aliasing is put forward.

本文对使用采样ADC把模拟信号转换为数字信号并通过计算数字信号的相关函数来实现锁定检测的技术进行了研究，在此基础上设计了一个多功能的数字LIA并在一些科学实验中进行了应用。本文对整周期采样和非整周期采样时的数字锁定检测技术分别进行了研究。(1)在整周期采样时，对被测信号进行采样得到信号序列，而参考序列由数学运算得到，通过计算信号序列和参考序列的互相关函数就可实现锁定检测。

One important feature ofHamiltonian systems is that it has energy(its energic function is Hamiltonian func-tion),then,its solutions on 2-dimensional plane are some contour lines,the points onstable manifold emanating from hyperbolic equilibrium point have the same energyas that on unstable manifold,then,one can guess that they form a closed curve,i.e.homoclinic orbits under certain conditions,and the contour lines in the innerpart of homoclinic orbit are periodic orbits.

哈氏系统的一个重要特征是它有能量存在(以Hamiltonian函数作为它的能量)，那么在二维平面上，它的解表现为一些等值线，从双曲平衡点发出的稳定流形和不稳定流形上的点具有相同的能量，那么可以猜测，在一定条件下它们构成一条封闭的曲线，即同宿轨，而且其内部的等值线都是周期轨道。

In this paper,some aufficient conditions of existence of periodic orbits of the typeBC* L￣∞in unimodal function s with kneading sequences BC are given.

本文给出了捏制序列为BC的单峰函数具有BC＊L￣∞型周期轨道的几个充分条件。

In this paper,the periodic solutions of a class of monlinear systems are studied by using the method of Liapunov function.

本文运用Liapuunov函数方法，研究了一类非线性系统的周期解，得到了存在唯一渐近稳定的周期解的充分条件。

In this paper,we study the existence.uniqueness and asymptotic stability of the periodic solutions for a class of nonautonomous systems by using the method of Liapunov Function.

利用Liapunov函数方法，研究了一类非自治系统周期解的存在唯一性及渐近稳定性，得到了存在唯一渐近稳定的周期解的充分条件。

In this papper, the methods of decomposition of large-scale system and Liapunov function are used in studying the existence of stationary oscillation of periodic interval system and some new results are obtained.

应用大系统的分解和Liapunov函数的方法研究了周期区间系统的平稳振荡的存在性问题，得到了一些新的结果。

By constructing a Liapunov function, we obtain some sufficient conditions which ensure the persistence of the first system, and the existence of periodic solutions of the second system which is established by using coincidence degree theory.

另外，我们也利用重合度理论得到了第二个系统正周期解存在的充分条件。

By using Mawhin\'s continuous theorem and liapunov function, sufficient conditions for the existence and globally asymptotic stability of positive periodic solutions of three systems are derived, respectively.

我们还利用Mawhin连续性定理分别建立了两个系统正周期解存在的充分条件。

Sufficient conditions for existence of positive periodic solutions of these systems are established and we investigate a stochastic Lotka-Volterra ecosystem, by use of the mixed quasi-monotone theory and Liapunov function method, some new results are obtained.

最后，我们研究了n种群随机Lotka-Volterra生态模型，利用混合单调流理论和It〓型随机微分方程知识，得到了其解过程的均方渐近稳定性和强生态稳定性的结果。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了