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101.
Synchronization performance in time-delayed random networks induced by diversity in system parameter 下载免费PDF全文
Synchronization rhythm and oscillating in biological systems can give clues to understanding the cooperation and competition between cells under appropriate biological and physical conditions. As a result, the network setting is appreciated to detect the stability and transition of collective behaviors in a network with different connection types. In this paper, the synchronization performance in time-delayed excitable homogeneous random networks(EHRNs) induced by diversity in system parameters is investigated by calculating the synchronization parameter and plotting the spatiotemporal evolution pattern, and distinct impacts induced by parameter-diversity are detected by setting different time delays. It is found that diversity has no distinct effect on the synchronization performance in EHRNs with small time delay being considered. When time delay is increased greatly, the synchronization performance of EHRN degenerates remarkably as diversity is increased. Surprisingly, by setting a moderate time delay, appropriate parameter-diversity can promote the synchronization performance in EHRNs, and can induce the synchronization transition from the asynchronous state to the weak synchronization. Moreover, the bistability phenomenon, which contains the states of asynchronous state and weak synchronization,is observed. Particularly, it is confirmed that the parameter-diversity promoted synchronization performance in time-delayed EHRN is manifested in the enhancement of the synchronization performance of individual oscillation and the increase of the number of synchronization transitions from the asynchronous state to the weak synchronization. Finally, we have revealed that this kind of parameter-diversity promoted synchronization performance is a robust phenomenon. 相似文献
102.
In this paper, the evolution of the pattern transition induced by the vortical electric field (VEF) is investigated. Firstly, a scheme is suggested to generate the VEF by changing the spatial magnetic field. Secondly, the VEF is imposed on the whole medium, and the evolutions of the spiral wave and the spatiotemporal chaos are investigated by using the numerical simulation. The result confirms that the drift and the breakup of the spiral wave and the new net-like pattern are observed when different polarized fields are imposed on the whole medium respectively. Finally, the pattern transition induced by the polarized field is discussed theoretically. 相似文献
103.
The effect of change in concentration of messenger molecule inositol
1,4,5-trisphosphate (IPspiral wave, Ca$^{2 + }$,
IPspiral wave, Ca$^{2 + }$,
IP$_{3}$ Project supported by the National
Natural Science Foundation of China (Grant Nos 10575041 and
10747005) 0545 The effect of change in concentration of messenger molecule inositol
1,4,5-trisphosphate (IP$_{3})$ on intracellular Ca$^{2 + }$spiral
pattern evolution is studied numerically. The results indicate that
when the IP$_{3}$ concentration decreases from 0.27\,$\mu $M, a
physiologically reasonable value, to different values, the spiral
centre drifts to the edge of the medium and disappears for a small
enough IP$_{3}$ concentration. The instability of spiral pattern can
be understood in terms of excitability-change controlled by the
IP$_{3}$ concentration. On the other hand, when the IP$_{3}$
concentration increases from 0.27\,$\mu $M, a homogeneous area with
a high Ca$^{2 + }$ concentration emerges and competes with the
spiral pattern. A high enough IP$_{3}$ concentration can lead the
homogeneous area to occupy the whole medium. The instability of
spiral pattern is ascribed to the change in stability of a
stationary state with a high Ca$^{2 + }$ concentration. 相似文献
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108.
石墨负载Pt催化剂的制备、表征及活性研究 总被引:1,自引:0,他引:1
Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The preparation parameters, including the reduction temperature, Pt loading and pyrolysis were studied. The optimal preparation conditions were 350 ℃ with Pt loading of 1.0%. Results show that the loading of Pt can significantly enhance catalytic activity of graphite and that Pt/graphite catalytic ozonation can effectively remove oxalic acid in aqueous solution. The BET surface area of graphite is much smaller than that of activated carbon, however, the catalytic activity of Pt/graphite towards oxalic acid degradation is higher than that of Pt/AC. The XPS results indicate that the active phase at catalyst surface is in the form of Pt0. Compared with that of reduction process in hydrogen, the activity of Pt/graphite catalyst decreases when it is prepared by pyrolysis in air due to the lower Pt dispersion on graphite surface. 相似文献
109.
燃料电池作为一种清洁高效的能量转换装置,被认为是构建未来社会可再生能源结构的关键一环。不同于质子交换膜燃料电池(PEMFC),碱性聚合物电解质燃料电池(APEFC)的出现使非贵金属催化剂的使用成为可能,因而受到了日益广泛的关注和研究。APEFC的关键结构是膜电极,主要由聚合物电解质膜和阴阳极(含催化层、气体扩散层)组成,膜电极是电化学反应发生的场所,其优劣直接决定着电池性能的好坏。因此,基于现有的碱性聚合物电解质及催化剂体系,如何构筑更加优化的膜电极结构,使APEFC发挥出更高的电池性能是亟待开展的研究。本文首先通过模板法在碱性聚合物电解质膜的表面构建出有序的锥形阵列,再将具有阵列结构的一侧作为阴极来构筑膜电极,同时,作为对比,制备了由无阵列结构的聚合物电解质膜构筑而成的膜电极,最后对基于两种不同膜电极的APEFC的电化学性能进行了对比研究。实验结果表明,锥形阵列结构可以将APEFC的峰值功率密度由1.04 W·cm-2显著提高到1.48 W·cm-2,这主要归因于在APEFC的阴极侧具有锥形阵列结构的聚合物电解质膜的亲水性的提升和催化剂电化学活性面积的增加。本工作为碱性聚合物电解质燃... 相似文献
110.