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21.
Experiments on an array of 64 globally coupled chaotic electrochemical oscillators were carried out. The array is heterogeneous due to small variations in the properties of the electrodes and there is also a small amount of noise. Over some ranges of the coupling parameter, dynamical clustering was observed. The precision-dependent cluster configuration is analyzed using hierarchical cluster trees. The cluster configurations varied with time: spontaneous changes of number of clusters and their configurations were detected. Simple transitions occurred with the switch of a single element or groups of elements. During more complicated transitions subclusters were exchanged among clusters but original cluster configurations were revisited. At weaker coupling the system itinerated among lower-dimensional quasistationary chaotic two-cluster states and higher-dimensional states with many clusters. In this region the transitions showed characteristics of on-off intermittency. 相似文献
22.
The effects of noise on phase synchronization (PS) of coupled chaotic oscillators are explored. In contrast to coupled periodic oscillators, noise is found to enhance phase synchronization significantly below the threshold of PS. This constructive role of noise has been verified experimentally with chaotic electrochemical oscillators of the electrodissolution of Ni in sulfuric acid solution. 相似文献
23.
24.
B. C. Sawyer B. K. Stuhl B. L. Lev J. Ye E. R. Hudson 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(2):197-209
The transverse motion inside a Stark decelerator plays a large role in the total efficiency of deceleration. We differentiate
between two separate regimes of molecule loss during the slowing process. The first mechanism involves distributed loss due
to coupling of transverse and longitudinal motion, while the second is a result of the rapid decrease of the molecular velocity
within the final few stages. In this work, we describe these effects and present means for overcoming them. Solutions based
on modified switching time sequences with the existing decelerator geometry lead to a large gain of stable molecules in the
intermediate velocity regime, but fail to address the loss at very low final velocities. We propose a new decelerator design,
the quadrupole-guiding decelerator, which eliminates distributed loss due to transverse/longitudinal couplings throughout
the slowing process and also exhibits gain over normal deceleration to the lowest velocities. 相似文献
25.
P. Beazley Cohen T. M. W. Eyre R. L. Hudson 《International Journal of Theoretical Physics》1995,34(8):1481-1486
A simple combinatorial formula is found for the product of two iterated quantum stochastic integrals, and used to find conditions that such an integral represent a unitary-valued or*-algebra homomorphism-valued process. 相似文献
26.
Serhiy Z. Malynych Alexander Tokarev Stephen Hudson John Ballato Konstantin G. Kornev 《Journal of magnetism and magnetic materials》2010,322(14):1894-1897
Imaging of micro- and nanofluidics is a challenge since the size of the channels is so small that the installment of additional optical and mechanical switches is very difficult. The size of the device and associated increase in viscous dissipation constitute another constraint. In response to these limitations, this work proposes and demonstrates the manipulation of light by adding a functional lens to control the light on demand. In the present work, this lens is realized by filling a hollow fiber with a colloid of superparamagnetic Fe3O4 nanoparticles. When the propagation of light is perpendicular to the magnetic field, this lens stretches the circular beam into a ribbon yielding a larger visible area. Potentially, one can apply a rotating magnetic field thus illuminating a larger spot size or creating other beam geometries. Such composite fibers might also be of value for Faraday isolation and other magneto-optic effects in optical fibers. 相似文献
27.
Stochastic temporal and spatiotemporal models of metastable pitting on a metal surface are presented. A stochastic reaction-diffusion model accounts for the effects of local changes in concentration, potential drop, and oxide film damage on the nucleation of subsequent events. The cooperative interactions among events can lead to the formation of clusters of metastable pits and to an explosive growth in the total number of pits. Recent progress in the studies of such phenomena is reviewed. New results based on a mean-field analysis of the model and numerical simulations on critical nucleation effects are reported. 相似文献
28.
Charles Brown Robert F. Hudson Gary A. Wartew H. Coates 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):481-488
Abstract The reaction between finely divided white phosphorus and several alkoxide ions in the presence of tetrachloromethane and excess of alcohol has been investigated under a variety of conditions. High yields of trialkylphosphite are obtained when two equivalents of alkoxide are used. With one equivalent of alkoxide, dialkylphosphonate is formed in comparable yield. Maximum yields of triester are obtained within 1–3 h at room temperature. Prolonged treatment results in the conversion of trialkylphosphite to phosphate by reaction with tetrachloromethane. Phenolate ions are unreactive under the same experimental conditions. The mechanism of the reaction is discussed. 相似文献
29.
Harry R. Hudson Rosalind J. Lee 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):1149-1155
AbstractReports on the anticancer activity of representative α-aminophosphonic acid derivatives are briefly reviewed, with comments where possible on modes of action. Preliminary in vitro screening results are also presented for selected dialkyl α-aryl (or heteroaryl)-α-(diphenylmethylamino)methanephosphonates against the National Cancer Institute (NCI) 60-cell line panel of human tumor cells, which showed average response parameters for active compounds of GI50 between 4.81 × 10?6 and 2.40 × 10?5 M, TGI between 1.88 and 6.28 × 10?5 M, and LC50 between 5.71 and 9.37 × 10?5 M. The highest activity was shown by the α-phenyl compound for which GI50 10?7 M was recorded against leukemia cell line MOLT-4. 相似文献
30.
We demonstrate a mode-locked, erbium-doped fiber laser with its repetition frequency synchronized to a second fiber laser via an intracavity electro-optic modulator (EOM). With servo control from the EOM (bandwidth approximately 230 kHz) and a slower speed intracavity piezoelectric transducer (resonance at approximately 20 kHz), we demonstrate stabilization of the repetition frequency with an in-loop rms timing jitter of 10 fs, integrated over a bandwidth from 1 Hz to 100 kHz. This represents what is to our knowledge the first time an EOM has been introduced inside a mode-locked laser cavity for fast servo action and the lowest timing jitter reported for a mode-locked fiber laser. 相似文献