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1.
In this paper, a novel multidimensional scaling (MDS) based on information measures method is proposed to analyze financial stock markets. In order to examine the effectiveness of this method, we applied it to the classification of two types of artificial series, the logistic map model and the cubic map model, as well as stock time series. Moreover, the traditional MDS using Euclidean dissimilarity is also provided as a reference for comparisons. The results show that the MDS based on information measures can give us more detailed, exact and clearer information on the classification of simulation series and stock time series than the MDS using Euclidean dissimilarity. In addition, the proposed graphical method may also assist in the construction of multivariate econometric models. 相似文献
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Annealing polyethylene terephthalate (PET)/polycarbonate (PC) blends enhance the transesterification reaction and increase the amount of copolymer at the interface of both polymers. The copolymer enhances the compatibility of PET with PC, because it contains both PET and PC blocks, which causes the interface between PET and PC to become fuzzy. When the PET/PC undergoes batch physical foaming with CO2, the copolymer significantly changes the resulting cell morphology, that is, the annealing time. Before annealing or in the absence of the copolymer, bubble nucleation occurs and dominates growth at the interface. When the PET/PC blends are annealed, the interface impedes bubble nucleation and growth. The polymer is stretched at the interface by bubble growth, forming fibril‐like structures connecting two polymer domains at the interface. Increased annealing time causes the interface to become more homogeneous and makes heterogeneous bubble nucleation difficult. At higher copolymer concentrations, the interface of PET and PC becomes fuzzy and the cell morphology becomes like those of foamed homogeneous polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 相似文献
3.
Pengjian Zuo Tao Wang Guangyu Cheng Chunyu Du Yulin Ma Xinqun Cheng Geping Yin 《Journal of Solid State Electrochemistry》2013,17(7):1955-1959
Li2FeSiO4/C cathode materials have been prepared using the conventional solid-state method by varying the sintering temperature (650 °C, 700 °C and 750 °C), and the structure and electrochemical performance of Li2FeSiO4/C materials are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge–discharge tests, respectively. The results show that Li2FeSiO4 nano-crystals with a diameter of about 6–8 nm are inbedded in the amorphous carbon, and the Li2FeSiO4/C material obtained at 700 °C exhibits an initial discharge capacity of 195 mA?h g?1 at 1/16 C in the potential range of 1.5–4.8 V. The excellent electrochemical performance of Li2FeSiO4/C attributes to the improvement of conductivity and reduction of impurity by the optimization of the sintering temperature. 相似文献
4.
In this paper, we applied multifractal modeling techniques to analyze the traffic data collected from the Beijing Yuquanying. The results indicated that multifractal characteristics obviously exist in the traffic system; the degree of fractality of these traffic data tends to increase as the traffic system becomes congested; the Hölder exponent that measures the local rate of fractality may be used as indicators to predict the presence of the traffic congestion. 相似文献
5.
Geng Tianfeng Du Chunyu Cheng Xinqun Xu Xing Jian Jiyuan He Xiaoshu Zuo Pengjian Yin Geping 《Journal of Solid State Electrochemistry》2019,23(1):101-108
Journal of Solid State Electrochemistry - Li-rich layered oxide (LrLO) cathode has attracted much attention for Li-ion batteries in recent years due to its superior capacity of exceeding... 相似文献
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In this paper, based on the Hirota bilinear method, a kind of lump solutions and two classes of interaction solutions are discussed to the \((2+1)\)-dimensional generalized KdV equation with the aid of symbolic computation system Mathematica. Analyticity is naturally guaranteed by taking special choices of the involved parameters to achieve a positive constant term. Particularly, these solutions with special values of the included parameters are plotted, as illustrative example. 相似文献
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Seismic wave control is very important both in civil and mechanical engineering. Common passive methods for isolating a building or a device include base isolators and tuned mass dampers. In the present paper, a time-varying controllable spring is considered as a vibration isolator for a linear mechanical system. The controller works as follows: When the seismic movement is active, the velocity of the moving mass is monitored as the reference velocity. When such reference velocity is positive, the stiffness is reduced; when it is negative, the stiffness is increased. Numerical investigations show that the controller is capable of filtering seismic excitation close to the natural frequency of the controlled system and reducing the total seismic energy transfer up to 5 times. The role played by the gravity in the active vibration filtering is pointed out by showing that no filtering action can be observed in gravity-free simulations. Moreover, control effectiveness has been proven for a measured seismic signal, showing its robustness in presence of noise. 相似文献
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In this paper, the Detrended Fluctuation Analysis (DFA) and Detrended Cross-Correlation Analysis (DCCA) are used to investigate
the stock markets. The DFA method is a widely-used method for the determination and detection of long-range correlations in
stock time series. DCCA is a recently developed method to quantify the cross-correlations of two non-stationary time series.
We report the results of correlation and cross-correlation behaviors in US and Chinese stock markets by using the DFA and
DCCA methods, respectively. The DCCA shows that there exists some crossovers in the cross-correlation fluctuation function
versus time scale of stock absolute returns. The cross-correlations in Chinese stock markets are stronger than those between
Chinese and US stock markets. After documenting the equal-time cross-correlations using DCCA method, we study the dynamics
of cross-correlations of stock series based on a time-delay. The time-dependence of the underlying cross-correlations is monitored
using a time window by step of 1 day. An interesting finding is that the cross-correlation exponents and crossovers demonstrate
periodical uncertainty changing with the time-delay. 相似文献
10.
The Bonhoeffer?Cvan der Pol (BVP) oscillator has widely application in the modeling of biological processes, and it also has rich nonlinear behavior including different topological properties between the continuous-time BVP oscillator and the discrete one. Multifractal Detrended Cross-Correlation Analysis (MF-DCCA) has proved useful in describing the correlations and detecting the scaling exponent of time series. We investigate the autocorrelations and cross-correlations of the time series in BVP model by using the MF-DCCA method. Our results show that there exist long range autocorrelations and cross-correlations in the BVP model time series, and that multifractal features are significant in the analyzed BVP model. 相似文献