离散谱

词组短语

discrete spectrum · point spectrum

与离散谱相关的网络例句 [注：此内容来源于网络，仅供参考]

This result can best be viewed as a quantum black hole version of the third law of thermodynamics. As a result of this area spectrum, the spectrum of M is discrete, bounded below, and can be made positive. Prom the physical point of view, the semiboundedness and positivity of the spectrum are very satisfying results: The semi-boundedness of the spectrum implies that one cannot extract an infinite amount of energy from the system, whereas the positivity of the spectrum is in agreement with the well-known positive-energy theorems of general relativity.

同时根据EMDA黑洞动力学，存在与面积谱对应的大于零且有下界的质量离散谱，从物理上来看，质量谱的半有界性意味着不可能从系统吸取无限的能量，而正定性则与广义相对论中的正能定理一致，也就说稳态轴对称EMDA时空的ADM能量总是大于零。

Spectral element methods for partial differencial equation is introduced in this study from viewpoint of the collocation approximation of Chebyshev polynomial. Wave Equation and its space discretization are deduced. Two time integral methods, central difference method and implicit Newmark method, are introduced, and their stability and applicability are also discussed in some details. The significance of absorbing boundary conditions in spectral element methods for Aeroacoustics is explained, and Clayton-Engquist-Majda absorbing boundary conditions is emphasized and introduced, then the discrete scheme of this boundary conditions is deduced and applied to spectral element methods for wave equation.

本文从Chebyshev多项式逼近理论出发，详细介绍了谱元方法求解偏微分方程的过程；推导了流体中的声波动方程并在空间上对其进行了谱元离散；详细讨论了两种时间积分方法──中心差分法和Newmark方法，分析了它们的稳定性条件，并从理论上对比了两种方法的优缺点和适用范围；将吸收边界条件推广应用于谱元方法求解气动声学问题中，重点介绍了Clayton-Engquist-Majda吸收边界条件的原理和公式，推导了该吸收边界条件的变分形式，并将其引入波动方程的离散形式中。

In Chapter three, we mainly discuss the numerical method of the one dimensional nonlinear Schr〓dinger equation

在第二章中，主要结果是讨论了一维非线性薛定谔方程的保结构离散化方法，采用谱方法给出了此方程的全离散计算格式。

In Chapter two, we discuss structure preserving discretization method for the one dimensional nonlinear Schr〓dinger equation with periodic boundary value condition by means of spectral method.

在第二章中，主要结果是讨论了一维非线性薛定谔方程的保结构离散化方法，采用谱方法给出了此方程的全离散计算格式。

After a particular parameter k,we introduce a gauge transformation which is arotation around the 2-axis.

因此在所得到的反散射方程中的离散谱部分有2N个极点的贡献。

Firstly,by using the estimating methodfor the compact embedding operators(from weighted Sobolev space to the weighted〓space),we obtain a necessary and sufficient condition for the discreteness of thespectrum of certain differential operators.Secondly,based on the property of thespectrum of difinitizable operators on the Krein space,we consider the left definitedifferential equations with middle deficiency indices,and give a completecharacterization for self-adjoint(J-self-adjoint)differential operators in theindefinite inner product space 〓.Especially,we prove that all the J-self-adjoint differential operators are definitizable.

我们首先运用加权Sobolev空间到加权〓空间嵌入算子紧性的判别方法，证明一类加权自伴微分算子具有离散谱的充要条件；然后，基于Krein空间上可定化算子谱的性质，对于具中间亏指数的左定型微分方程，建立其相应的微分算式在不定度规空间〓上所生成自伴算子的完备性刻画（特别证明了J-自伴微分算子具有可定化性）。

Taking advantage of retractility and time-delay characteristics of wavelet, this paper solves the problems of fixed resolving power and large redundance of the information caused by traditional sonogram analysis by choosing the scale of wavelet correctly.

本文将离散小波变换应用于蝙蝠回声定位叫声的分析中，利用小波的伸缩和时移特性，通过对小波尺度的适当离散，解决了传统语谱分析的分辨率固定、信息冗余量大的问题。

Due to existing signal processing technology's shortage such aslow measurement, narrow measurement range precision and other poor performance, we introduced a high-precise signal processing technology:firstly,to get power spectrum with Hanning windowed Welch modified periodogram, search its peak value frequency;secondly, to apply zooming analysis via Goertzel algorithm;at last,to get a highly precise doppler frequency with energy centrobaric rectifying algorithm.

针对存在的缺点，本文提出了一种应用于激光多普勒测速的高精度信号处理技术，即首先利用加Hanning窗的Welch修正周期图算法得到信号功率谱，搜索其谱峰值频率，接着利用Goertzel频谱细化算法对搜索的谱峰进行细化分析，再引入能量重心频谱校正算法对细化后的谱峰进行校正分析，从而将离散频谱分析算法、频谱细化算法和频谱校正算法三者有机结合起来，充分发挥各自的优点：通过加Hanning窗的Welch修正周期图算法快速得到功率谱及峰值频率，通过Goertzel算法获得分析频带的高分辨率频谱，然后通过能量重心校正算法对细化后的频谱进行高精度校正，这样不仅保证了算法的高效性，而且大大提高了分析的精度。

Insection 4.3, semi-discrete and fully discrete Fourier spectral and pseudo-spectral schemes are constructed. The convergence and stability for the schemes are proved, and the error estimates are obtained.Chapter 5, consider the damped coupled generalized nonlinear wave equations. In section 5.2, by coupled a priori estimates and Galerkin method, prove the existence and uniqueness of the global smooth solution for the periodic initial value problem and obtain the existence of global attractors.

第四章，考虑一类具耗散的广义KdV方程组的周期初值问题，在第二节中证明了整体光滑解的存在性和唯一性，得到整体吸引子；在第三节中构造了半离散和全离散的Fourier谱格式和拟谱格式，在整体光滑解存在的条件下，证明了这些格式解的收敛性，并得到了误差估计。

In the first part, first of all, we have a priori estimate for solution of the reaction-diffusion equation with initial condition and Dirichret boundary conditions. Then, we construct a semidiscrete Legendre pseudospectral scheme, and have a priori estimate for approximate solution. We discuss the asymptotic stability of approximate solution. At last, we get a error estimation on large time for solution of the semidiscrete system.

首先，对此类方程初边值问题的解进行了先验估计；然后建立方程半离散的Legendre拟谱格式，并对近似解进行了先验估计，讨论了近似解的渐近稳定性；最后，得到了半离散系统解的长时间误差估计。

与离散谱相关的网络解释 [注：此内容来源于网络，仅供参考]

discrete set：离散集

discrete series 离散序列 | discrete set 离散集 | discrete spectrum 离散谱

discrete spectrum：离散谱

discrete source 离散信源 | discrete spectrum 离散谱 | discrete state 离散状态

purely discrete spectrum：纯离散谱

pure surd 纯不尽根 | purely discrete spectrum 纯离散谱 | purely imaginary number 虚数

quasi discrete spectrum：拟离散谱

quasi discrete space 拟离散空间 | quasi discrete spectrum 拟离散谱 | quasi distance 拟距离

discrete mode spectrum：离散模谱

discrete message 离散信息 | discrete mode spectrum 离散模谱 | discrete picture 离散图像

discrete state：离散状态

discrete spectrum 离散谱 | discrete state 离散状态 | discrete stochastic process 离散随机过程

discrete state：不连续态,不连续状态,离散状态,分离状态

discrete spectrum 不连续谱 | discrete state 不连续态,不连续状态,离散状态,分离状态 | discrete stochastic process 离散随机过程

point spectrum：点谱,离散谱

point source radiator 点源辐射器 | point spectrum 点谱,离散谱 | point spread function 点扩散函数

pure point spectrum：纯离散谱

pure mathematics 抽象数学 | pure point spectrum 纯离散谱 | pure predicate calculus of first order 一阶纯谓词演算

quasi discrete space：拟离散空间

quasi directed set 拟有向集 | quasi discrete space 拟离散空间 | quasi discrete spectrum 拟离散谱