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991.
992.
993.
Scaling behavior of earthquakes’ inter-events time series 总被引:1,自引:0,他引:1
Shahriar Shadkhoo Fakhteh Ghanbarnejad Gholam R. Jafari Mohammad R. R. Tabar 《Central European Journal of Physics》2009,7(3):620-623
In this paper, we investigate the statistical and scaling properties of the California earthquakes’ inter-events over a period
of the recent 40 years. To detect long-term correlations behavior, we apply detrended fluctuation analysis (DFA), which can
systematically detect and overcome nonstationarities in the data set at all time scales. We calculate for various earthquakes
with magnitudes larger than a given M. The results indicate that the Hurst exponent decreases with increasing M; characterized
by a Hurst exponent, which is given by, H = 0:34 + 1:53/M, indicating that for events with very large magnitudes M, the Hurst exponent decreases to 0:50, which is for independent
events.
相似文献
994.
Nicola Pizzolato Davide Valenti Dominique Persano Adorno Bernardo Spagnolo 《Central European Journal of Physics》2009,7(3):541-548
The evolutionary dynamics of a system of cancerous cells in a model of chronic myeloid leukemia (CML) is investigated by a
statistical approach. Cancer progression is explored by applying a Monte Carlo method to simulate the stochastic behavior
of cell reproduction and death in a population of blood cells which can experience genetic mutations. In CML front line therapy
is represented by the tyrosine kinase inhibitor imatinib which strongly affects the reproduction of leukemic cells only. In
this work, we analyze the effects of a targeted therapy on the evolutionary dynamics of normal, first-mutant and cancerous
cell populations. Several scenarios of the evolutionary dynamics of imatinib-treated leukemic cells are described as a consequence
of the efficacy of the different modelled therapies. We show how the patient response to the therapy changes when a high value
of the mutation rate from healthy to cancerous cells is present. Our results are in agreement with clinical observations.
Unfortunately, development of resistance to imatinib is observed in a fraction of patients, whose blood cells are characterized
by an increasing number of genetic alterations. We find that the occurrence of resistance to the therapy can be related to
a progressive increase of deleterious mutations.
相似文献
995.
The stochastic resonance (SR) phenomenon induced by a multiplicative periodic signal in a logistic growth model with correlated
noises is studied by using the theory of signal-to-noise ratio (SNR) in the adiabatic limit. The expressions of the SNR are obtained. The effects of multiplicative noise intensity α and additive noise intensity D, and correlated intensity λ on the SNR are discussed respectively. It is found that the existence of a maximum in the SNR is the identifying characteristic of the SR phenomena. In comparison with the SR induced by additive periodic signal, some
new features are found: (1) When SNR as a function of λ for fixed ratio of α and D, the varying of α can induce a stochastic multi-resonance, and can induce a re-entrant transition of the peaks in SNR vs λ; (2) There exhibits a doubly critical phenomenon for SNR vs D and λ, i.e., the increasing of D (or λ) can induce the critical phenomenon for SNR with respect to λ (or D); (3) The doubly stochastic resonance effect appears when α and D are simultaneously varying in SNR, i.e., the increment of one noise intensity can help the SR on another noise intensity come forth.
相似文献
996.
利用磁控溅射方法在100℃的MgO单晶基片上制备了[FePt/Au]10多层膜,并研究了采用FePt/Au多层膜结构对FePt薄膜的有序化温度、矫顽力(HC)、垂直磁各向异性、晶粒尺寸以及颗粒间磁交换耦合作用的影响.磁性测试结果表明:FePt/Au多层膜在退火后具有较高的HC、良好的垂直磁各向异性、较小的晶粒尺寸且无磁交换耦合作用.截面高分辨电镜分析表明:Au可以缓解MgO和FePt之间较大的晶格错配,从而促进薄
关键词:
0-FePt薄膜')" href="#">L10-FePt薄膜
有序化温度
垂直磁各向异性
磁交换耦合作用 相似文献
997.
通过数值模拟方法, 研究了在具有稳定次阈值振荡特性的二维映射神经元体系中, 噪声对体系非线性动力学的调控作用. 通过计算发现了噪声诱导的动作电位和随机共振现象. 另外,还研究了体系的控制参数及输入信号的频率对体系动力学的影响, 发现了该体系中频率依赖的随机共振现象.
关键词:
二维映射神经元模型
次阈值振荡
高斯白噪声
随机共振 相似文献
998.
999.
In this paper, two-mode displaced excited squeezed vacuum states (TDESVS) are constructed and their normalization and completeness are investigated. Using the entangled state representation and Weyl ordering form of the Wigner operator, the Wigner functions of TDESVS are obtained and the variations of Wigner functions with the parameters m, n and r are investigated. Besides, two marginal distributions of Wigner functions of TDESVS are obtained, which exhibit some entangled properties of the two-particle's system in TDESVS. 相似文献
1000.
S. Sankarrajan S. Aravindan R. Yuvakkumar K. Sakthipandi V. Rajendran 《Journal of magnetism and magnetic materials》2009,321(21):3611-3620
Nd1−xSrxMnO3 perovskite manganite material with different compositions (x=0.31, 0.35, 0.37, 0.39 and 0.41) have been prepared employing solid-state reaction technique. The ultrasonic velocities and attenuation of the above samples have been measured employing through transmission method operated at a fundamental frequency of 5 MHz over wide range of temperatures. The temperature dependence of ultrasonic velocities, attenuation, relative percentage variation in velocities and elastic constants show an interesting anomaly in all compositions. The observed anomalies in ultrasonic parameters at Tc in all compositions have been revealed in terms of existence of ferromagnetic (FM) state. Similarly, the anomalies at Tco show the transition from FM to charge-ordered antiferromagnetic (AFM) state. The observed results have been used to explore the competitions between FM and AFM. 相似文献