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1.
In this Letter, the effects of random shortcuts in an array of coupled nonlinear chaotic pendulums and their ability to control the dynamical behavior of the system are investigated. We show that random shortcuts can induce periodic synchronized spatiotemporal motions, even though all oscillators are chaotic when uncoupled. This process exhibits a nonmonotonic dependence on the density of shortcuts. Specifically, there is an optimal amount of random shortcuts, which can induce the most ordered motion characterized by the largest order parameter that is introduced to measure the spatiotemporal order. Our results imply that topological randomness can tame spatiotemporal chaos. 相似文献
2.
We have investigated the length scale dependence of the transient evolution of surface roughness during homoepitaxial growth on GaAs(100), patterning the surface lithographically with an array of cylindrical pits of systematically varied sizes and spacings. Our atomic force microscopy measurements show that the amplitude of the surface corrugation has nonmonotonic behavior in both the length scale dependence and time evolution. This behavior allows us to rule out a number of existing continuum models of growth. 相似文献
3.
A two-dimensional periodic array of quantum dots with two laterally coupled leads in a magnetic field is considered.The model of electron transport through the system based on the theory of self-adjoint extensions of symmetric operators is suggested.We obtain the formula for the transmission coefficient and investigate its dependence on the magnetic field. 相似文献
4.
The grain-size dependence of certain mechanical properties of commercially pure titanium under deformation at room temperature is examined. A decrease in the grain size is found to provide a continuous improvement in strength, lower work hardening, and nonmonotonic dependence of the length of the uniform deformation stage. Furthermore, localized deformation in the neck and total plasticity before fracture exhibit a low sensitivity to the grain size. A yield tooth and plateau occur in the flow curve as the structure is reduced down to a certain grain size. The grain-size dependence of the mechanical behavior of the material and its relation to the dislocation redistribution are discussed. 相似文献
5.
We have used numerical calculations based on Mie theory to analyze the near field distribution patterns for 4–150 nm spherical
silver nanoparticles (nanospheres). We have shown that as the nanoparticle sizes increase, the region where “hot spots” are
concentrated is shifted to the forward hemisphere. We have observed a nonmonotonic dependence of the maximum attainable local
field enhancement factor on the size of the silver nanospheres. We have determined a correlation between the optimal nanosphere
size for the maximum attainable local field enhancement factor and the optical absorption efficiency factor. We have established
a nonmonotonic dependence of the optimal size of the nanoparticles and the maximum attainable local field enhancement factor
on the refractive index of the surrounding medium.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 6, pp. 831–837, November–December, 2008. 相似文献
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G. I. Tselikov S. G. Dorofeev O. A. Shalygina V. Yu. Timoshenko 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(12):1726-1728
The photoluminescence properties of colloidal CdSe quantum dots with a mean size of 3 nm were studied. The experimental results
revealed the nonmonotonic dependence of the photoluminescence peak’s position as a function of the excitation photon energy
being varied from 2.41 to 3.68 eV. This effect can be explained by the size distribution of the nanocrystals and the spectral
dependence of their absorption coefficients. 相似文献
8.
This paper reports on the results of investigations into the influence of Schottky regions formed in the vicinity of crystallite boundaries in polycrystalline ferroelectrics on their permittivity. The dependence of the dielectric properties of the Schottky regions on the orientation of the spontaneous polarization in the adjacent region of the crystallite is taken into consideration. It is demonstrated that nonmonotonic dependences of the permittivity and its relative change on the crystallite size under uniaxial compression are associated with the presence of the domain structure in polycrystalline ferroelectrics. 相似文献
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A. M. Vorobei O. I. Pokrovskiy K. B. Ustinovich L. I. Krotova O. O. Parenago V. V. Lunin 《Russian Journal of Physical Chemistry B, Focus on Physics》2016,10(7):1072-1077
The capability of arbidol microparticle preparation by supercritical antisolvent (SAS) precipitation was demonstrated. A nonmonotonic dependence of the average particle size on the concentration was found, while the position of the minimum is dependent on the type of solvent used. It is possible to prepare Arbidol particles of various morphology and size from several microns to several hundred microns depending on the conditions. 相似文献
11.
Light absorption and scattering by weakly absorbing layers of close-packed fine-grained silver halide particles was studied. Absorption characteristics of an elementary volume and a photolayer were found to have a nonlinear and nonmonotonic dependence on the concentration. Qualitative specific features of this dependence in the range of medium values of volume concentrations from 0.4 to 0.8 were expressed by an empirical formula. The average cosine of the depth brightness diagram and the probability of photon survival Λ in a concentrated photolayer were calculated. The analysis of changes in Λ in a close-packed medium in a more general case, irrespective of the size and the degree of absorption of particles, was carried out. A conclusion was made concerning the character of changes in the scattering indicatrix of a photolayer caused by an increase of its density. 相似文献
12.
A. A. Dobretsova Z. D. Kvon L. S. Braginskii M. V. Entin N. N. Mikhailov 《JETP Letters》2016,104(6):388-391
The mobility of Dirac electrons (DEs) in HgTe quantum wells with the thickness close to the critical value corresponding to the transition from the direct to inverted spectrum has been studied experimentally and theoretically. The nonmonotonic dependence of this mobility on the electron density is found experimentally. The theory of DE scattering on impurities and fluctuations of the thickness of a well caused by its roughnesses is elaborated. This theory is in good agreement with experiment and explains the observed nonmonotonicity by the decrease in the ratio of the de Broglie wavelength of DEs to the characteristic size of the roughness with the increase in their concentration. 相似文献
13.
Energy relaxation is studied in the spin-polarized disordered electron systems in the diffusive regime. We derive a quantum kinetic equation in which the kernel of the electron-electron collision integral explicitly depends on the electron magnetization. As a consequence, the inelastic scattering rate has a nonmonotonic dependence on the spin polarization of the system. 相似文献
14.
研究了不同周期信号调制下非对称双稳耦合网络系统的尺度随机共振问题. 针对该网络系统, 首先运用高斯近似和役使原理对其进行了降维, 推导了其简化模型. 在绝热近似条件下, 利用Fokker-Planck方程分别得到了余弦信号和矩形信号调制下信噪比的解析表达式. 在此基础上, 研究了系统的尺度随机共振行为, 并讨论了非对称性、噪声强度、周期信号的振幅和耦合系数对系统尺度随机共振的影响. 结果表明, 两种情形下信噪比均是系统尺度的非单调函数, 说明在此网络系统中产生了共振现象.
关键词:
尺度随机共振
非对称双稳耦合网络系统
余弦信号
矩形信号 相似文献
15.
The Hall effect in heterostructures with a two-dimensional array of tunneling-coupled Ge quantum dots grown by molecular-beam epitaxy on Si is investigated. The conductivity of these structures in zero magnetic field at 4.2 K varies in the range of 10?12?10?4 Ω?1, which includes both the diffusive transport under weak localization conditions and hopping conduction. It is shown that the Hall effect can be discerned against the magnetoresistance-related background in both high- and low-conductivity structures. The Hall coefficient in the hopping regime exhibits a nonmonotonic dependence on the occupancy of quantum dots by holes. This behavior correlates with that of the localization length of the hole wavefunctions. 相似文献
16.
Zaccarelli E Mayer C Asteriadi A Likos CN Sciortino F Roovers J Iatrou H Hadjichristidis N Tartaglia P Löwen H Vlassopoulos D 《Physical review letters》2005,95(26):268301
We examine the vitrification and melting of asymmetric star polymer mixtures by combining rheological measurements with mode coupling theory. We identify two types of glassy states, a single glass, in which the small component is fluid in the glassy matrix of the big one, and a double glass, in which both components are vitrified. Addition of small-star polymers leads to melting of both glasses, and the melting curve has a nonmonotonic dependence on the star-star size ratio. The phenomenon opens new ways for externally steering the rheological behavior of soft matter systems. 相似文献
17.
We find that the potential energy distribution of atoms in clusters can consistently explain many important phenomena related to the phase changes of clusters, such as the nonmonotonic variation of melting temperature with size, the dependence of melting, boiling, and sublimation temperatures on the interatomic potentials, the existence of a surface-melted phase, and the absence of a premelting peak in heat capacity curves. We also find a new type of premelting mechanism in double icosahedral Pd19 clusters, where one of the two internal atoms escapes to the surface at the premelting temperature. 相似文献
18.
We consider the propagation of super-Gaussian monochromatic laser beams in a three-dimensional array of quantum dots coupled
by the tunneling effect along one axis. The electron energy spectrum of the system corresponds to the Hubbard model, where
the Coulomb interaction of electrons in quantum dots is taken into account. The field of the laser beam is described by the
Maxwell equations, from which a nonhomogeneous wave equation for the vector potential is obtained. In the approximation of
slowly varying amplitudes and phases, the wave equation is reduced to a phenomenological equation describing the electromagnetic
field in an array of chains of quantum dots. We study the influence of the system parameters and the frequency of the laser-beam
field on the propagation in the medium by solving numerically the phenomenological equation. We obtain the dependence of the
factor characterizing the diffraction blooming of the beam in an array of chains of quantum dots on the parameters of the
system’s electron energy spectrum. 相似文献
19.
Synchronization in an array of mutually coupled systems with a finite time delay in coupling is studied using the Josephson junction as a model system. The sum of the transverse Lyapunov exponents is evaluated as a function of the parameters by linearizing the equation about the synchronization manifold. The dependence of synchronization on damping parameter, coupling constant,and time delay is studied numerically. The change in the dynamics of the system due to time delay and phase difference between the applied fields is studied. The case where a small frequency detuning between the applied fields is also discussed. 相似文献
20.
We consider the patterns manifested during the formation of the spatial intensity distribution of an acoustic field excited by a vertical array in a deep-water oceanic waveguide with an underwater sound channel open to the surface and an acoustically transparent bottom. The study focuses on the dependence of the spatial divergence of multimode beams on the angle of compensation of an array emitting a tone signal. It is established that if the size of the array aperture significantly exceeds the optimal size, then at a certain angle of compensation appreciably differing from zero, a multimode beam forms with minimal diffraction divergence even in the absence of bending points and smooth extrema of the dependence of the length of the ray cycle on the ray parameter. 相似文献