Nonlinear energy harvesting with dual resonant zones based on rotating system

An electromagnetic nonlinear energy harvester(NEH)based on a rotating system is proposed,of which the host system rotates at a constant speed and vibrates harmonically in the vertical direction.This kind of device exhibits several resonant phenomena due to the combinations of the rotating and the vibration frequencies of the host system as well as the cubic nonlinearity of the NEH.The governing equation of motion for the NEH is derived,and the dynamic responses and output power are investigated with the multiple scale method under the 1:1 primary and 2:1 superharmonic resonant conditions.The effects of system parameters including the nondimensional external frequency,the rotating speed,and the nonlinear stiffness on the responses of free vibration for the system are studied.The results of the primary resonance show that the responses exhibit not only the resonant characteristics but also the nonlinear dynamic characteristics such as the saddle-node(SN)bifurcation.The coexistence of multiple solutions and the varying trends of responses are verified with the direct numerical simulation.Moreover,the effects of system parameters on the average output power are investigated.The results of the analyses on the two resonant conditions indicate that the large power can be harvested in two resonant frequency bands.The effect of resonance on the output power is dominant for the 2:1 superharmonic resonance.Moreover,the results also show that introducing the nonlinearity can increase the value of the output power in large frequency bands and induce the occurence of new frequency bands to harvest the large power.The efficiency of the harvested power could be improved by the combined effects of the resonance as well as the nonlinearity of the NEH device.Suitable parameter conditions could help optimize the power harvesting in design.

EXISTENCE OF GLOBAL L~∞ SOLUTIONS TO A GENERALIZED n × n HYPERBOLIC SYSTEM OF LEROUX TYPE

In this article, we give the existence of global L∞bounded entropy solutions to the Cauchy problem of a generalized n × n hyperbolic system of Le Roux type. The main difficulty lies in establishing some compactness estimates of the viscosity solutions because the system has been generalized from 2×2 to n×n and more linearly degenerate characteristic fields emerged, and the emergence of singularity in the region {v1= 0} is another difficulty.We obtain the existence of the global weak solutions using the compensated compactness method coupled with the construction of entropy-entropy flux and BV estimates on viscous solutions.

Fast and hydrosensitive switching of plasmonic nanocavities via photothermal effect

Metallic nanoplasmonics,due to its extremely small size and ultrafast speed,has been one of the key components for next-generation information technology.It is vital that the highly tunable nanoplasmonic system in the solid state can be achieved for optoelectronic devices,which,still remains elusive for the visible region.Here we sandwich vanadyl oxalate(VOC_(2)O_(4))thin films in-between gold nanoparticles and gold film to establish thermo-responsive nanoantennas.The thickness of the VOC_(2)O_(4) composite films remains almost unchanged within the temperature cycles between 15℃ and 80℃,while the refractive index of the films decreases with the increase of temperature due to the dehydration,which results in blueshift of the plasmon peak up to 60 nm.The plasmon resonances can be fully recovered when the temperature cools down again.This process is reversible within the temperature range of 15℃–80℃,which can be optically modulated with photothermal effect.Such thermo-responsive plasmonic nanoantenna works in the solid state with hundreds of kilohertz switching speed,which is highly compatible with traditional optoelectronic devices.It can be envisioned that this thermo-responsive optical thin film can be a promising candidate for integrated nanoplasmonic and optoelectronic devices.

Description of rotational properties of the superheavy nucleus ^(256,258,260)Rf by projected shell model

Band structure of the Z=104 nucleus256Rf has been a recent research focus in nuclear physics.We performed projected shell model calculations for this and some other neighboring Rf isotopes.Specifically,we studied rotational properties of these nuclei and showed that variations in dynamic moment of inertia were sensitive to single-particle structures,which may be useful information for locating the anticipated island of stability.Electromagnetic transition properties were also calculated,and measurable quantities were predicted for further experimental test.