CHARACTERISTICS OF TECTONIC MIXTITE ZONE IN THE LANCANG RIVER,WESTERN YUNNAN     

Liu Dengzhong  Wang Guozhi  Tao Xiaofeng  Zhui Lidong  Li Youguo  Xu XinhuangWT  ”BX 《地学前缘》2000,(Z1)

CHARACTERISTICS OF TECTONIC MIXTITE ZONE IN THE LANCANG RIVER,WESTERN YUNNAN  相似文献   

Ricker子波视主频的变化对混沌振子检测效果的影响   总被引：2，自引：2，他引：0       下载免费PDF全文

袁野  罗正玮  李月 《地球物理学进展》2006,21(1):70-73

针对地震勘探资料中存在加性强随机噪声干扰,已经提出用混沌振子系统处理的方法技术.为完善该方法,需要研究诸如地震勘探同相轴完整程度、组成同相轴的地震子波变化等对系统检测效果的影响.本文以Ricker子波模拟地震子波,研究Ricker子波视主频变化的相应检测效果.研究结果：随着Ricker子波视主频的升高,检测SNR逐渐变差,在高频部分SNR的变化明显比低频部分缓慢;在通常地震勘探频率范围内,混沌振子系统检测SNR有可能部分补偿由于地震波传播引起的幅度降低;为检测由畸变子波构成的同相轴提供一定的可能.  相似文献   

The origin of chaotic behaviour in the Miranda-Umbriel 3 : 1 resonances     

Jacques Henrard  Massae Sato 《Celestial Mechanics and Dynamical Astronomy》1989,47(4):391-417

We have investigated the pericentric resonances through which Miranda and Umbriel are believed to have passed when, due to tidal evolution, their orbital mean motions reached a 3 : 1 commensurability. Our investigation is based upon a perturbative treatment. The predictions of this theory are in good agreement with the results of numerical integrations concerning both the extend of the chaotic layers generated by the separatrices of the primary resonances and the location of the secondary resonances. The effect of tidal evolution is discussed on the bases of the adiatatic invariant theory and its extension to separatrix crossing. We recover qualitatively the mean features of the numerical experiments of Tittermore and Wisdom (1988–1989), Dermott et al (1988) and Malhotra and Dermott (1989).  相似文献   

Complexity Theory of Natural Disasters; Boundaries of Self-Structured Domains     

Scheidegger  A. E. 《Natural Hazards》1997,16(2-3):103-112

Disasters are often represented as complete breakdowns of quasi-stationary states in a landscape, but may also be part of the normal evolution of such states. A landscape is, in fact, an open, nonlinear, dynamic system where the tectonic uplift and the seismic activity represent the input, the mass wastage and the relief degradation the output. The apparent 'stability' is due to the fact that open, nonlinear dynamic systems tend to develop into relatively stable, self-organized ordered states 'at the edge of chaos', with a fractal attractor. Short of complete breakdown, such systems re-establish order in steps of various magnitudes which have a power-law distribution. Because of the fractal structure of the basic attractor, all subsets follow a power law which accounts for the distribution of the steps of recovery. As the domains of quasi-stationarity at the edge of chaos are represented by finite windows, the power-law does not cover all magnitudes. The stationarity windows are not only limited in range, but also in space and time. This should be taken into account in the assessment of hazards. Examples are given from seismology (earthquake frequency), volcanology (eruption frequency), river hydrology (flood frequency) and geomorphology (landslides).  相似文献   

Regular and Chaotic Solutions of the Sitnikov Problem near the 3/2 Commensurability     

M. A. Jalali  S. H. Pourtakdoust 《Celestial Mechanics and Dynamical Astronomy》1997,68(2):151-162

Regular solutions at the 3/2 commensurability are investigated forSitnikovs problem. Utilizing a rotating coordinate system and theaveraging method, approximate analytical equations are obtained for thePoincare sections by means of Jacobian elliptic functions and 3periodicsolutions are generated explicitly. It is revealed that the system exhibitsheteroclinic orbits to saddle points. It is also shown that chaotic regionemerging from the destroyed invariant tori, can easily be seen for certaineccentricities. The procedure of the current study provides reliable answersfor the long-time behavior of the system near resonances.  相似文献   

矢量地图数据的加密算法   总被引：2，自引：0，他引：2  

闵连权 《海洋测绘》2005,25(2):55-57

加密技术是保障数据安全的最主要的手段，结合矢量地图数据的特点，设计了一种基于混沌序列的数据加密算法。实验证明，该算法加密效率高，保密性好。  相似文献   

遗传算法改进的BP神经网络在混沌径流时间序列预测中的应用     

刘媛媛  练继建  朱云 《水文》2007,27(2):45-48

区别于传统的提取混沌时间序列饱和嵌入维数的方法,本文利用人工神经网络成功地对水库混沌径流时间序列的饱和嵌入维数进行了提取,计算了该时间序列里的最大Lyapunov指数,两种方法结果都证明了该时间序列的混沌性。并用遗传算法对BP神经网络进行了改进,利用该模型对三门峡水库混沌径流时间序列进行了预测。实例计算表明该方法解决了BP神经网络收敛速度慢和易于陷入极小值的问题,大大提高了BP神经网络的计算精度和收敛速度。无论在计算精度上还是在收敛次数上都优于没有改进的BP神经网络。  相似文献   

Experimental and theoretical simulations of seismic poundings between two adjacent structures     

K. T. Chau  X. X. Wei  X. Guo  C. Y. Shen 《地震工程与结构动力学》2003,32(4):537-554

Shaking table tests have been carried out to investigate the pounding phenomenon between two steel towers of different natural frequencies and damping ratios, subject to different combinations of stand‐off distance and seismic excitations. Both harmonic waves and ground motions of the 1940 El Centro earthquake are used as input. Subjected to sinusoidal excitations, poundings between the two towers could appear as either periodic or chaotic. For periodic poundings, impact normally occurs once within each excitation cycle or within every other excitation cycle. A type of periodic group poundings was also observed for the first time (i.e. a group of non‐periodic poundings repeating themselves periodically). Chaotic motions develop when the difference of the natural frequency of the two towers become larger. Under sinusoidal excitations, the maximum relative impact velocity always develops at an excitation frequency between the natural frequencies of the two towers. Both analytical and numerical predictions of the relative impact velocity, the maximum stand‐off distance, and the excitation frequency range for pounding occurrences were made and found to be comparable with the experimental observations in most of the cases. The stand‐off distance attains a maximum when the excitation frequency is close to that of the more flexible tower. Pounding appears to amplify the response of the stiffer structure but suppress that of the more flexible structure; and this agrees qualitatively with previous shaking table tests and theoretical studies. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

COMPLEXITY AND CHAOTIC DYNAMICS OF ROCK FAULTING   总被引：1，自引：0，他引：1  

TANKaixuan XIEYanshi CHENGuanghao HUANGXiaonai 《大地构造与成矿学(英文版)》2003,27(1):104-111

Fault is a complex dynamic system controlled by the coupling of rock texture, reaction, fluid flow, stress, and rock deformation mechanism. A coupled reaction-transport- mechanical dynamic model for fault system is established and described in this paper. An example is presented for the Shuikoushan deposit, Hunan. The results of dynamic simulation indicate that the evolution and magnitude of fracture permeability of different rocks are different, and that faulting can enhance the spatial heterogeneity of rock permeability and facilitate fluid flow and mineralization in local fault zone. The pressure for a fault usually shows a variation mode of aperiodic oscillation with time, which reflects the chaotic behavior of the evolution of a fault.  相似文献   

An Analytic Model of Three-Body Mean Motion Resonances     

D. Nesvorný  A. Morbidelli 《Celestial Mechanics and Dynamical Astronomy》1998,71(4):243-271

It has been recently shown that the resonances among the mean motions of an asteroid, Jupiter and Saturn are very important for the origin of chaos in the asteroid belt. We develop an analytic model for these three-body resonances which allows quantitative predictions on their amplitude and libration timescale. We also discuss why these resonances are chaotic. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献