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121.
122.
Émeline Schmisser 《Stochastic Processes and their Applications》2019,129(12):5364-5405
In this article, we consider a jump diffusion process , with drift function , diffusion coefficient and jump coefficient . This process is observed at discrete times . The sampling interval tends to 0 and the time interval tends to infinity. We assume that is ergodic, strictly stationary and exponentially -mixing. We use a penalized least-square approach to compute adaptive estimators of the functions and . We provide bounds for the risks of the two estimators. 相似文献
123.
This paper addresses a previously unexplored regime of three-dimensional dissipative chaotic flows in which all but one of the nonlinearities are quadratic. The simplest such systems are determined, and their equilibria and stability are described. These systems often have one or more infinite lines of equilibrium points and sometimes have stable equilibria that coexist with the strange attractors, which are sometimes hidden. Furthermore, the coefficient of the single nonquadratic term provides a simple means for scaling the amplitude and frequency of the system. 相似文献
124.
WANG QianXin & XU TianHe School of Information Physics Geomatics Engineering Central South University Changsha China Geodesy Department Xi'an Research Institute of Surveying Mapping Xi'an 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
The truncation error and propagation error are analyzed for velocity determination through differential GPS carrier phase observations,and an approach for the choice of the best number of points for the central difference method is developed.In order to overcome the disadvantages of existing GPS velocity determination methods,a new velocity determination algorithm is presented,based on combining carrier phase and Doppler observations.The basic idea is that two types of observation are combined by adding the... 相似文献
125.
A laser coherent detection system of 1550 nm wavelength was presented, and experimental research on detecting micro-Doppler effect in a dynamic target was developed. In this paper, the return signal in the time domain is decomposed into a set of components in different wavelet-scales by multi-resolution analysis, and the components are associated with the vibrational motions in a target. The micro-Doppler signatures are extracted by applying the reconstruction (inverse wavelet transform). During the course of the final data processing frequency analysis and time–frequency analysis are applied to analyze the vibrational signals and estimate the motion parameters successfully. The experimental results indicate that the micro-Doppler information in a moving can be effectively detected, and tiny vibrational signatures also can be acquired effectively by wavelet multi-resolution analysis and time–frequency analysis. 相似文献
126.
Hua‐Wei Li Sabyasachi Kar Pinghui Jiang 《International journal of quantum chemistry》2013,113(10):1493-1497
The effects of Debye plasma on the frequency‐dependent polarizabilities of Li and Na atoms are investigated using symplectic algorithm within the framework of the pseudostate summation technique. Dynamic dipole polarizabilities of Li (2s 2S) and Na(3s 2S) as functions of scaled number density of the plasma electrons for arbitrary plasma temperature are presented. Screening effects on the resonance frequencies are also presented. In free‐atomic cases, our calculated results are comparable with the reported theoretical and experimental predictions. © 2012 Wiley Periodicals, Inc. 相似文献
127.
Binary dual-frequency nematic liquid crystals synthesised at the Military University of Technology were measured by dielectric means. All the investigated materials exhibit low crossover frequency. They were composed of only two molecules with longitudinal and transverse dipole moments. The main difference is the molecular weight of the molecules. Results of relaxation parameters of detected mode and crossover frequency are shown. The influence of structure on ion conductivity is discussed. The broad phase transition from an isotropic phase to a nematic one was observed. 相似文献
128.
129.
通过钌的络合物前驱体和硝酸钡的共浸渍制备的Ru Ba K/AC催化剂氨合成转化效率高,其氨合成转化频率在0.87~1.30 s-1之间,与氯化钌制备的Ru/AC催化剂相比,其转化频率提高幅度在26%~88%。共浸渍法制备的催化剂氨合成转化效率高,其主要原因可能是共浸渍法制备的催化剂钌粒子粒径分布区间较窄,易形成更多的活性位;钌表面氢的吸附受到抑制,氮更易活化,因而催化效率更高。 相似文献
130.
Pei Dang 《Mathematical Methods in the Applied Sciences》2015,38(2):365-379
In this study, we propose some new uncertainty principles for periodic signals with sharper lower bounds than those in the existing ones. The improved lower bounds, in particular, are related to the frequency of the signal. Three examples are employed to demonstrate sharpness of the new uncertainty principles. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献