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941.
Xiaojun Duan Jubo Zhu Zhengming Wang 《International Journal of Infrared and Millimeter Waves》2001,22(1):133-140
Linear filter may hide simple nonlinearity of chaotic dynamics, which would decrease the accuracy of parameter estimation, and reduce the effect of signal processing. Based on theoretical and experimental analysis, this paper provides a method to recover the dynamics. An example of radar data proves that the dynamics hidden in observed data can be found by inverse filter of chaos. It is also pointed out that inverse filter of chaos can be applied to mine inner regulation of some time series and estimate parameters of nonlinear models in data processing for radar. And the method is significant to clutter modeling. 相似文献
942.
The eigenstates and eigenspectrum of a charged particle in a one-dimensional semiconductor superlattice with an impurity under the action of a dc electric field are investigated employing the single-band tight-binding model. We find that the system undergoes a series of avoided crossings, at which resonant oscillations between the impurity and its nearest neighbour occur if appropriate conditions are met, suggesting an effective two-level approximation. This phenomenon shows that introducing an impurity in a perfect lattice provides a promising structure for the observation of terahertz radiation. 相似文献
943.
Dynamical properties of two-band superlattices with strong interband coupling in real space under the action of ac and dc-ac fields 下载免费PDF全文
Within a two-band tight-binding model driven by ac and dc-ac electric fields, using numerical methods, we investigate the dynamics of electrons and the quasi-energy spectrum of the system with strong interband coupling in real space. We find that when the bandwidth is suppressed to a value much smaller than the field frequency, the dynamical localization can exist in the system. The corresponding regions are found for the occurrence of dynamical localization in the parameter space. 相似文献
944.
The effects of dust temperature and the dust charge variation in a dusty plasma with vortex—like ion distribution 下载免费PDF全文
By considering both the dust temperature and the dust charge variation in dusty plasma with vortex-like ion distribution, we obtained a modified Korteweg-de Vries equation. It indicates that the effect of dust charge variation can cause the one-dimensional soliton amplitude to become larger, and the dust temperature can cause the soliton amplitude to become larger as well. Moreover, as the dust temperature increases, the soliton amplitude will increase. 相似文献
945.
采用流变学法系统地考察了部分水解聚丙烯酰胺(HPAM)/Cr(III)交联体系的 反应动力学。HPAM溶液的粘性模量G”大于弹性模量G’,且其数值随时间不发生变 化,体系为粘性溶液。而HPAM/Cr(III)体系的G’和G”的数值都随时间变化,G” 在反应开始阶段大于G’,当反应进行一段时间后,G’超过G”占据主要地位,体 系成为弹性体系。交联过程可分为三个阶段:第一上升阶段,平缓上升阶段和第二 上升阶段。利用G’~ t曲线可以推测反应机理。实验发现成胶速率随反应物HPAM 和Cr(III)的浓度的增加而增加,而成胶时间缩短。在羧基浓度过量的情况下,交 联反应对Cr(III)浓度的反应级数是1。凝胶的有效弹性交联密度随聚合物浓度的增 加而增,且随凝胶反应的进行而增加。凝胶的交联点间的平均分子量随Cr(III)浓 度的增加和交联反应的进行而下降。 相似文献
946.
Spectroscopic analysis of asymmetric top free radicals 总被引:1,自引:0,他引:1
Yuyan Liu Xiaoyong Liu Hongping Liu Yuanqing Guo Guangming Huang Jieli Lin Hui Gao Chuanxi Duan 《中国科学B辑(英文版)》2001,44(1):7-16
Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the
representation and basis vector, identification of energy levels, the selection rules, the relative intensity, and Zeeman
tuning rate, were elucidated systematically. Introducing the high-order centrifugal distortion terms into the effective Hamiltonian,
the precision for calculation has been improved substantially, which allows us to analyze the high-lying rotational transitions.
A global analysis of all available spectra of14N16O2 in the ground vibronic state has been made to obtain a set of molecular constants of14N16O2 in the ground vibronic state which is the most precise and extensive so far. Using the improved parameters, some FIR LMR
lines left unassigned hitherto have been identified successfully. 相似文献
947.
Ren Xiaoming Duan Chunying Zhu Huizhen Meng Qingjin Hu Chuanjiang Lu Changsheng Liu Yongjiang 《Transition Metal Chemistry》2001,26(3):295-299
Interesting complexes containing a mnt2– bridge, based on the reaction of [M(mnt)2]2– [M = Ni or Cu] with [Cu(LH)]+, have been prepared and characterized by e.s.m.s., i.r and u.v–vis. spectroscopic techniques and by electrochemistry. The complexes show weak antiferromagnetic interactions between magnetic centers. The X-ray analysis of the molecular structure of [Cu(LH)]2[Ni(mnt)2] has been completed. It structurally features the CN group of mnt2– which can act as a bridging ligand between two transition metals. 相似文献
948.
949.
The problem of a Griffith crack in an unbounded orthotropic functionally graded material subjected to antipole shear impact was studied. The shear moduli in two directions of the functionally graded material were assumed to vary proportionately as definite gradient. By using integral transforms and dual integral equations, the local dynamic stress field was obtained. The results of dynamic stress intensity factor show that increasing shear moduli’s gradient of FGM or increasing the shear modulus in direction perpendicular to crack surface can restrain the magnitude of dynamic stress intensity factor. 相似文献
950.
4th-order spline wavelets on a bounded interval 总被引:1,自引:0,他引:1
IntroductionWaveletanalysishasexperiencedanenormousdevelopmentinrecentyears.Oneoftheimportantfieldsisthenumericalanalysisofdifferentialequations.Theadvantageofadoptingwaveletshasbeenreported[1~ 4].Classicalapproachestowaveletconstructiondealwithmultireso… 相似文献