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BANDWIDTH　SELECTION　IN　NONPARAMETRIC　spectral　density　ESTIMATION　OF　THE　STATIONARY　GAUSSIAN　PROCESS

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Acta Mathematicae Applicatae Sinica 1996年第4期12卷 363-370页

作者：于丹 Institute of Systems Science the Chinese Academy of Sciences Beijing China

We propose a method for estimating mean squared error and bandwidth in the windowedspectral density estimation of a stationary Gaussian process, and also provide a method forestimating the second order derivative of t... 详细信息

关键词： Stationary Gaussian process spectral density periodogram windowed spectral estimate bandwidth spectral window mean squared error

The dynamics of one-dimensional random quantum XY system with Dzyaloshinskii-Moriya interaction

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Chinese Physics B 2013年第3期22卷 481-486页

作者：李银芳孔祥木 Shandong Provincial Key Laboratory of Laser Polarization and Information Technology Department of PhysicsQufu Normal University

In this paper,the effects of random variables on the dynamics of the s = 1/2 XY model with the Dzyaloshinskii-Moriya interaction are *** means of the recurrence relation method in the high-temperature limit,we calculate the spin autocorrelation functions as well as the corresponding spectral densities for the cases that the exchange couplings between spins or external magnetic fields satisfy the double-Gaussian *** is found that when the standard deviation of random exchange coupling δJ（or the standard deviation of random external field δB） is small,the dynamics of the system undergoes a crossover from a collective-mode behavior to a central-peak ***,when δJ（or δB） is large,the crossover vanishes,and the system shows a central-peak behavior or the most disordered *** also analyze the cases in which the exchange couplings or the external fields satisfy the bimodal and the Gaussian *** results show that for all the cases considered,the dynamics of the above system is similar to that of the one-dimensional random XY model.

关键词： correlation function spectral density Dzyaloshinskii-Moriya interaction recurrence relation method

Cross-spectral recognition method of bridge deck aerodynamic admittance function

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Earthquake Engineering and Engineering Vibration 2015年第4期14卷 595-609页

作者： Zhao Lin Ge Yaojun State Key Lab for Disaster Reduction in Civil Engineering Tongji University

This study proposes a new identification algorithm about the admittance function, which can estimate the full set of six aerodynamic admittance functions considering cross power spectral density functions about the forces and the turbulence components. The method was first numerically validated through Monte Carlo simulations, and then adopted to estimate the aerodynamic admittance of a streamlined bridge deck. The identification method was further validated through a comparison between the numerical calculation and wind tunnel tests on a moving bridge section. © 2015, Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag Berlin Heidelberg.

关键词： Algorithms Bridge decks Intelligent systems Monte Carlo methods Numerical methods Power spectral density spectral density Wind stress Wind tunnels

The spin dynamics of the random transverse Ising chain with a double-Gaussian disorder

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Chinese Physics B 2014年第8期23卷 527-536页

作者：刘中强姜素蓉孔祥木 College of Physics and Engineering Qufu Normal University

The dynamical properties of one-dimensional random transverse Ising model （RTIM） with a double-Gaussian disorder is investigated by the recursion method. Based on the first twelve recurrences derived analytically, the spin autocorrelation function （SAF） and associated spectral density at high temperature were obtained numerically. Our results indicate that when the standard deviation σg （or OrB） of the exchange couplings Ji （or the random transverse fields Bi） is small, no long-time tail appears in the SAE The spin system undergoes a crossover from a central-peak behavior to a collectivemode behavior, which is the dynamical characteristics of RTIM with the bimodal disorder. However, when σJ （or σB） is large enough, the system exhibits similar dynamics behaviors to those of the RTIM with the Gaussian disorder, i.e., the system exhibits an enhanced central-peak behavior for large σJ or a disordered behavior for large σB. In this instance, SAFs exhibit a similar long-time tail, i.e., C（t） ~ t ^-2 for large t. Similar properties are obtained when Ji （or Bi） satisfy the double-exponential distribution or the double-uniform distribution. Besides, when both the standard deviations and the mean values of the exchange couplings are small, the effects of the Gaussian random bonds may drive the system undergo two crossovers from a triplet state to a doublet state, and then to a collective-mode state.

关键词： random transverse Ising model spin autocorrelation function spectral density long-time tail

Method of evaluation of a mirror surface figure based on frequency domain and its application for the Giant Steerable Science Mirror of the Thirty Meter Telescope

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Chinese Optics Letters 2015年第4期13卷 31-36页

作者：杨飞刘国军安其昌张学军 State Key Laboratory of High Power Semiconductor Lasers Changchun University of Science and Technology Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences

We propose a sub-aperture stitching algorithm based on a frequency domain that can be denoted as a power spectral density （PSD）. Our algorithm is verified by the experimental data obtained from measuring a epl.23 m mirror at the Changchun Institute of Optics, Fine Mechanics and Physics. Then, we apply it to the Great Steer- ing Science Mirror （GSSM） of the Thirty Meter Telescope （TMT） with the simulated data before the preliminary design phase, and obtain a more objective result on the frequency domain aberrations. Therefore, the sub-aperture stitching-based PSD is expected to be useful for specifying a large aperture mirror surface for mirror vendors.

关键词： Algorithms Frequency domain analysis Optical telescopes Power spectral density spectral density Telescopes

Scattering of scalar light wave from a Gaussian—Schell model medium

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Chinese Physics B 2010年第8期19卷 391-394页

作者：王涛赵道木 Department of Physics Zhejiang University

The scattering of scalar light wave from a random medium with a correlation function of Gaussian-Schell model distribution is studied. It is shown that the properties of the scattered field, i.e., the spectral density and the spectral degree of coherence of the scattered field, are closely related to the properties of the scattering medium, including the scaled effective radius and the scaled correlation length of the correlation function.

关键词： scattering Gaussian-Schell model medium spectral density coherence

spectral characterisation of colour printer based on a novel grey component replacement method

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Chinese Optics Letters 2011年第7期9卷 94-97页

作者：郭晋一徐海松 M.Ronnier Luo 王彬宇 State Key Laboratory of Modern Optical Instrumentation Zhejiang University Department of Colour Science University of Leeds

Conventional printer characterisation models are generally based on the assumption that the densities of primary colours are additive. However, additivity failure frequently occurs in practice. We propose a novel grey component replacement （GCR） method based on the spectral density sub-additivity equations in this letter for spectral characterisation of a 4-ink colour printer. The method effectively correct the error caused by additivity failure. Real high-quality hardcopy samples are produced as evidence of the feasibility of the proposed method and to evaluate the model performance. Finally, the GCR model for characterising colour printer with high spectral and colorimetric Drediction accuracv is established.

关键词： Color Color printing spectral density

Optically trapping Rayleigh particles by using focused partially coherent multi-rotating elliptical Gaussian beams

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Chinese Optics Letters 2016年第1期14卷 65-69页

作者：彭喜陈迟到陈波彭玉莲周美玲杨相波邓冬梅 Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices South China Normal University CAS Key Laboratory of Geospace Environment University of Science & Technology of ChinaChinese Academy of Sciences

By investigating the cross-spectral density of partially coherent multi-rotating elliptical Gaussian beams （REGBs） that propagate through a focusing optical system, we obtain the radiation force on a Rayleigh particle. The radiation force distribution is studied under different beam indexes, coherence widths, and elliptical ratios of the partially coherent multi REGBs. The transverse and the longitudinal trapping ranges can increase at the focal plane by increasing the beam index or decreasing the coherence width. The range of the trapped particle radii increases as the elliptical ratio increases. Furthermore, we analyze the trapping stability.

关键词： Optical systems spectral density

Propagation Properties of Multi-Hyperbolic Sine-Correlated Beams in Oceanic Turbulence

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Optics and Photonics Journal 2022年第4期12卷 64-77页

作者： Chaoran Hu College of Science University of Shanghai for Science and Technology Shanghai China

As a new partially coherent beam, the propagation properties of the multi-hyperbolic sine-correlated (MHSC) beams in turbulent atmospheres have been studied. But as another important medium, the propagation properties of MHSC beams in oceanic turbulence. This paper has studied these questions in detail. The analytical formulas of spectral density and degree of coherence for the propagation are derived and the numerical simulations are represented. It is found that the intensity patterns of MHSC beams will evolve from dark-hollow profiles into Gaussian profiles caused by oceanic turbulence and will degenerate more rapidly with stronger oceanic turbulence. In addition, the coherence region becomes larger with decreasing in the dissipation rate of turbulence kinetic energy in unit mass liquid or increasing in the relative intensity of temperature and salinity fluctuations, mean square temperature dissipation rate. We also find that the degree of coherence of MHSC beams with a higher-order N will decrease more slowly than those of hyperbolic sine-correlated (HSC) beams.

关键词： Multi-Hyperbolic Sine-Correlated Beams Oceanic Turbulence spectral density Degree of Coherence Propagate