17 resultados para recurrence

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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In order to study the earthquake recurrence and the characteristics of earthquake series, rupture tests of rock samples and plexiglass samples were made. On rock samples, a number of acoustic emission (AE) and strain measuring points were deployed; the load was one side direct shear. The variation characteristics of AE and strain at different detecting points around the extra large fracture were observed and studied. On plexiglass samples, a series of inclined cracks were prefabricated by a small-scale compressive testing machine. The samples were then loaded on a shockproof platen, when the samples were loaded, the stress intensity factor (SIF) was determined by the laser interferometric technique and shadow optical method of caustics. The fracture conditions such as material toughness around the extra large fracture were also studied. From those experimental results and the theory of fracture mechanics, the earthquake recurrence period and the trend of post-seismic development were studied.

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Recurrence plot technique of DNA sequences is established on metric representation and employed to analyze correlation structure of nucleotide strings. It is found that, in the transference of nucleotide strings, a human DNA fragment has a major correlation distance, but a yeast chromosome's correlation distance has a constant increasing. (C) 2004 Elsevier B.V All rights reserved.

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The divergence of properties from one location to another within a soil mass is termed spatial variability, which traditionally includes three parameters the mean, the standard deviation, and the scale of fluctuation, in order to stochastically describe a soil property. Among them, determining the scale of fluctuation in the evaluation of spatial variability of soil profiles is not easy due to soil condition complexity. A simplified procedure is presented in the paper to determine the scale of fluctuation combined recurrence averaging and weighted linear regression. The alternative approach utilizes widely usable spreadsheet to solve the problem more directly and efficiently.

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Recurrence is a key characteristic in the development of epilepsy. It remains unclear whether seizure recurrence is sensitive to postseizure stress. Here, tonic-clonic seizures were induced with a convulsive dose of pentylenetetrazole (PTZ), and acute seizure recurrence was evoked with a subconvulsive dose of the drug. We found that stress inhibited seizure recurrence when applied 30 minutes or 2 hours, but not 4 hours, after the tonic-clonic seizure. The time-dependent anti-recurrence effect of stress was mimicked by the stress hormone corticosterone and blocked by co-administration of mineralocorticoid and glucocorticoid receptor antagonists. Furthermore, in a PTZ-induced epileptic kindling model, corticosterone administered 30 minutes after each seizure decreased the extent of seizures both during the kindling establishment and in the following challenge test. These results provide novel insights into both the mechanisms of and therapeutic strategies for epilepsy. (C) 2010 Elsevier Inc. All rights reserved.

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The generalized Shmuely Difference Algorithm (GSDA) is presented here to analyze the dynamic fracture performance of orthogonal-anisotropic composite materials, such as glass fibre reinforced phenolplast. The difference recurrence Formulae and boundary condition difference extrapolation formulae are derived and programmed. The dynamic stress intensity factors (DSIF) of the isotropic and anisotropic centrally cracked plates are computed respectively using GSDA and compared with that published previously. GSDA is proved effective and reliable. Copyright (C) 1996 Elsevier Science Ltd.

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Detailed analysis of some difficult aspects has been made from modeling the platemovement. A new method of using differential density of material (instead of differentialtemperature) has been developed in the experiments. The effect of convection of mantleon the plate movement has been studied using a centrifugal technique, and a patternshowing the recurrence of the plate movement has been successfully obtained. In this paper, a criterion De=Dm is presented for the similarity of the model to thecounterpart of the original mantle. According to the criterion, what happens in the modelin a span of ten minutes suggests a process of the "original model" going on in geologi-cal time of three million years.

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A repeat-until-success (RUS) measurement-based scheme for the implementation of the distributed quantum computation by using single-photon interference at a 50:50 beam splitter is proposed. It is shown that the 50:50 beam splitter can naturally project a suitably encoded matter-photon state to either a desired entangling gate-operated state of the matter qubits or to their initial state when the photon is detected. The recurrence of the initial state permits us to implement the desired entangling gate in a RUS way. To implement a distributed quantum computation we suggest an encoding method by means of the effect of dipole-induced transparency proposed recently [E. Waks and J. Vuckovic, Phys. Rev. Lett. 96, 153601 (2006)]. The effects of the unfavorable factors on our scheme are also discussed.

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The coupled differential recurrence equations for the corrections to the paraxial approximation solutions in transversely nonuniform refractive-index media are established in terms of the perturbation method. All the corrections (including the longitudinal field corrections) to the paraxial approximation solutions are presented in the weak-guidance approximation. As a concrete application, the first-order longitudinal field correction and the second-order transverse field correction to the paraxial approximation of a Gaussian beam propagating in a transversely quadratic refractive index medium are analytically investigated. (C) 1999 Optical Society of America [S0740-3232(99)00310-5].

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采用Berreman特征矩阵方法,通过数值计算研究了双折射薄膜的反射、透射等光谱响应特性。依据电磁场理论的电场分量、磁场分量的界面连续条件,推导了光波在各向异性双轴薄膜中的Berreman转移矩阵,用以分析含有各向异性介质层的复杂薄膜系统的光学性质。这些矩阵递推关系包含了界面处的多点反射,适用于一般的各向异性的多层膜系统,包括入射媒质或基底为各向异性的情况。在文中给出了各向同性入射媒质双轴各向异性膜层一各向同性基底薄膜系统的计算结果,验证了该计算方法的可行性,以此作为进一步研究各向异性薄膜和相关光学薄膜器

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0-1背包问题是经典的组合优化问题与NP完全问题,具有重要的应用价值与理论意义.本文使用PAR(Partition and Recurrence)方法形式化推导了0-1背包问题的高效动态规划算法程序.通过类比分析,该问题的若干变形问题的算法也可推导得到,算法通过PAR平台的自动生成系统转换成可执行语言程序并运行通过,保证了该类0-1背包问题算法的正确性和可靠性.本文主要的贡献是将PAR方法推广到能处理带约束条件的组合优化类问题,大大扩展了PAR方法的应用范围,为形式化开发高效高可信组合优化类算法开辟了一条新途径.

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Global transposable characteristics in the complete DNA sequence of the Saccharomyces cevevisiae yeast is determined by using the metric representation and recurrence plot methods. On the basis of the correlation distance of nucleotide strings, 16 chromosome sequences of the yeast, which are divided into 5 groups, display 4 kinds of the fundamental transposable characteristics: a short increasing period, a long increasing quasi-period, a long major value and hardly relevant.

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The effects of the transition dipole moment function (TDMF) on the dynamics Of O-3 photodissociation in the Hartley band have been exploited by means of exact 3D time-dependent wavepacket method using the SW potential energy surface [J. Chem. Phys. 78 (1983) 7191]. The calculations show that the explicit inclusion of the TDMF results in slight uniform reductions for the intensities of recurrence peaks of the autocorrelation function and a slight broadening of the absorption spectrum, in comparison with the result where the TDMF is assumed to be constant. The pattern of recurrence structures of the autocorrelation function is essentially unaffected. (C) 2001 Elsevier Science B.V. All rights reserved.