查询词典 spectral analysis

School of Electronic and Information Engineering,Dalian University of Technology,Dalian,Liaoning 116024,ChinaStable processes can better model the impulsive random signals and noises in physical observation.This paper briefly describes its spectral representation,proposes a new different spectral density from power spectrum density of second order processes,thus can get a new concept of stable white noise based on covariation spectrum,and a method of identification of nonlinear PAR system based on least p-norm.

描述了稳定分布的谱表示，提出了共变谱密度的概念，得到一种基于自共变序列与共变谱的稳定分布白噪声与有色噪声的概念及其判断标准，对传统意义上的白噪声进行了广义化，依据多项式自回归系统模型，对基于稳定白噪声输入的系统输出非线性稳定有色噪声建立其非线性PAR模型，提出基于最小P范数的EIRLP算法对非线性PAR系统进行辨识。

The Cholesky decomposition of cross spectral density matrix was approximated and reduced, and then the modified spectral representation method is efficient and requires less computer memory, which is suitable for simulating spatial wind fields of long span bridges.

针对现有Deodatis方法模拟大跨度桥梁空间脉动风场中存在的计算量问题，通过对谱分解矩阵引入插值近似，减少谱分解的次数，从而提高该谐波合成法的计算效率，并节省内存花费，实现了对三维空间脉动风场的有效模拟。

PSD method for identifying cross power spectral density of distributed excitation force is discussed by calculating cross power spectral density of measured response.

功率谱密度函数识别法则是以系统反应之交叉功率谱密度函数识别外力之交叉功率谱密度函数。

In order to construct the spectral decomposition of the Frobenius-Perron operator for a general Chebyshev maps We define a suitable dual pairs or rigged Hilbert space, which provides mathematical meaning for the spectral decomposition.

为了构建广义Chebyshev映射在Frobenius-Perron算子下的一种谱分解。

For Dryden power spectral density function, using the rational spectral theory to set up the linear state-space model.

针对Dryden频谱函数，通过有理谱成形理论，建立了阵风的线性化模型。

According to spectral characteristics of the HCVAW arc in a body, energy factor which value equals to the ratio of two spectral lines' intensity, was defined.When τ's value was less than 0.1, the HCVAW arc was exhibitive of diffusedshape with lower energy density instinct; and when τ's value was higher than 0.5,the arc was a fine-constricted arc with higher energy density.

从积聚态电弧的谱线空间分布来看，阳极材料为水冷铜板时，自空心阴极端面到阳极工件，氩原子谱线相对辐射强度具有比氩一次离子谱线相对辐射强度更快的减弱趋势，最大辐射强度均出现在距空心阴极端面2mm左右的位置。

A efficient LU decomposition method is spectral factorization. That is, after the minimum phase correlative function of each array of matrix had be given by a spectral factorization method, all of the functions are arranged in a position according to its former location to get a lower triangular matrix.

谱法LU分解的优点是在对大量具有相同非零结构的矩阵分解时，通过建立包含所有具有不同非零元素的列对应的自相关函数的分解表，使得随后的所有矩阵分解只需通过查表实现。

The intensity of grating diffraction spectrum is obtained by the Fourier series expansion of the transmissivity function. Finally, the design feasibility is analyzed by comparing the minimum signal spectral intensity with the maximal spectral intensity of the background light and the noise intensity.

通过对透射率函数的傅立叶级数展开，得到光栅衍射谱线的强度，对信号光谱线的最小强度、背景光谱线的最大强度和噪声强度的比较，得到设计的可行性。

One of the important tasks in my dissertation is to investigate Fraunhofer diffraction pattern of a polychromatic, spatially coherent wave diffracted by an annular aperture. The phenomena of spectral anomalies in the vicinity of the Airy rings in Fraunhofer diffraction pattern are investigated in detail. The effect of the parameters of the annular aperture on the spectral changes is studied particularly.

本学位论文的一部分内容进一步研究了在夫琅和费衍射模型下，多色空间相干光经过环形光阑衍射后的光谱变化情况，详细讨论了在该模型下振幅为零的点附近的光谱奇异现象，着重研究了改变环形光阑参数等对光谱变化的影响。

Further, with the help of Riccati equations, an infinite number of conservation laws for the solton hierarchy are deduced. For the sake of simplicity, taking the general TD hierarchy as an illustrative example, we prove that its 2×2 Lenard pair of operators forms a Hamiltonian pair. Thus the isospectral evolution TD hierarchy is the general Hamiltonian system and possesses the Bi-Hamiltonian structures and Multi-Hamiltonian structures. By using the method of derivation of functional under some constraint condition, a complete one-to-one correspondence between the Hamiltonian functions of the hierarchy and its conservation density functions can be built. These results can also be applied to the isospectral evolution soliton hierarchy of this paper. Finally, there's a gauge transformation between the spectral problem of this paper and the AKNS system. Moreover, the potentials in these spectral problems satisfy the general Miura transformation, the corresponding relationship between the two soliton hierarchies is also given.

进一步本文还通过特征函数的组合关系所满足的Riccati方程，得到了该等谱方程族的无穷多个守恒律；为简便起见，本文以广义TD族为例，由它的2×2 Lenard算子对的性质证明了此算子对为Hamilton算子对，这说明广义TD族是广义Hamilton系统且具有Bi-Hamilton结构和Multi-Hamilton结构；进而利用它的依赖于谱参数的一般守恒密度的积分在约束条件下求泛函导数的方法，得到了广义TD族的Hamilton函数与守恒密度之间的对应关系，这些性质对于由本文提出的2×2谱问题所导出的等谱孤子族仍成立；另外此谱问题与AKNS系统存在着规范变换，位势之间有广义Miura变换，而孤子方程之间也满足一定的等价关系。

Salt is good, but if the salt becomes flat and tasteless, with what do you season it?

14：33 盐本是好的，盐若失了味，可用什么叫它再咸呢？

He reiterated that the PLA is an army of the people under the leadership of the Communist Party of China.

他重申，人民解放军是在中国共产党领导下的人民军队。