Electromagnetic tunneling through conjugated single-negative metamaterial pairs and double-positive layer with high-magnetic fields

We show that resonant tunneling of electromagnetic （EM） fields can occur through a six-layer structure con- sisting of two pairs of bilayer slabs： one＇being an epsilon-negative layer and the other being a mu-negative layer with a double-positive （DPS） medium and air. This type of tunneling is accompanied by high-magnetic field. The Poynting vector distributions and the material dissipation are studied. Our results demonstrate that the EM field in the structure is controlled flexibly by single-negative media and DPS slab. Therefore, this structure has potential applications in wireless energy transfer.     

An adiabatic quantum optimization for exact cover 3 problem

A perturbation method is applied to study the structure of the ground state of the adiabatic quantum optimization for the exact cover 3 problem. It is found that the instantaneous ground state near the end of the evolution is mainly composed of the eigenstates of the problem Hamiltonian, which are Hamming close to the solution state. And the instantaneous ground state immediately after the starting is mainly formed of low energy eigenstates of the problem Hamiltonian. These results are then applied to estimate the minimum gap for a special case.     

Hybrid device for acoustic noise reduction and energy harvesting based on a silicon micro-perforated panel structure

A kind of hybrid device for acoustic noise reduction and vibration energy harvesting based on the silicon micro- perforated panel （MPP） resonant structure is investigated in the article. The critical parts of the device include MPP and energy harvesting membranes. They are all fabricated by means of silicon micro-electro-mechanical systems （MEMS） tech- nology. The silicon MPP has dense and accurate micro-holes. This noise reduction structure has the advantages of wide band and higher absorption coefficients. The vibration energy harvesting part is formed by square piezoelectric membranes arranged in rows. ZnO material is used as it has a good compatibility with the fabrication process. The MPP, piezo- electric membranes, and metal bracket are assembled into a hybrid device with multifunctions. The device exhibits good performances of acoustic noise absorption and acoustic-electric conversion. Its maximum open circuit voltage achieves 69.41 mV.     

The interaction between zonal flow and Rossby waves with scalar nonlinearity

The nonlinear interactions between zonal flow and Rossby waves are studied by numerical simulations with focus on the effects of scalar nonlinearity. The numerical results show that the scalar nonlinearity has an appreciable influence on the Rossby dipole evolution and can reduce the threshold of the disturbance energy increase.     

Second-order Born calculation of coplanar symmetric(e, 2e) process on Mg

The second-order distorted wave Born aPl6roximation （DWBA） method is employed to investigate the triple differen- tial cross sections （TDCS） of coplanar doubly symmetric （e, 2e） collisions for magnesium at excess energies of 6 eV-20 eV. Comparing with the standard first-order DWBA calculations, the inclusion of the second-order Born term in the scattering amplitude improves the degree of agreement with experiments, especially for backward scattering region of TDCS. This indicates that the present second-order Born term is capable to give a reasonable correction to DWBA model in studying coplanar symmetric （e, 2e） problems of two-valence-electron target in low energy range.     

Broadband energy harvesting via magnetic coupling between two movable magnets

Harvesting energy from ambient mechanical vibrations by the piezoelectric effect has been proposed for powering microelectromechanical systems and replacing batteries that have a finite life span. A conventional piezoelectric energy harvester （PEH） is usually designed as a linear resonator, and suffers from a narrow operating bandwidth. To achieve broadband energy harvesting, in this paper we introduce a concept and describe the realization of a novel nonlinear PEH. The proposed PEH consists of a primary piezoelectric cantilever beam coupled to an auxiliary piezoelectric cantilever beam through two movable magnets. For predicting the nonlinear response from the proposed PEH, lumped parameter models are established for the two beams. Both simulation and experiment reveal that for the primary beam, the introduction of magnetic coupling can expand the operating bandwidth as well as improve the output voltage. For the auxiliary beam, the magnitude of the output voltage is slightly reduced, but additional output is observed at off-resonance frequencies. Therefore, broadband energy harvesting can be obtained from both the primary beam and the auxiliary beam.     

Relativistic symmetries of Deng Fan and Eckart potentials with Coulomb-like and Yukawa-like tensor interactions

Relativistic symmetries of the Dirac equation under spin and pseudo-spin symmetries are investigated and a combina- tion of Deng-Fan and Eckart potentials with Coulomb-like and Yukawa-like tensor interaction terms are considered. The energy equation is obtained by using the Nikiforov-Uvarov method and the corresponding wave functions are expressed in terms of the hypergeometric functions. The effects of the Coulomb and Yukawa tensor interactions are numerically discussed as well.     

Intersubband transitions in InxAl（l-x）N/InyGa（l-y）N quantum well operating at 1.55 μm

In this paper, we theoretically study the effects of doping concentration ND and an external electric field on the intersubband transitions in InxAl（l-x）N/InyGa（l-y）N single quantum well by solving the Schrodinger and Poisson equations self-consistently. Obtained results including transition energies, the band structure, and the optical absorption have been discussed. The lowest three intersubband transitions （E2 -El）, （E3 -El）, and （E3 -E2） are calculated as functions of doping concentration ND. By increasing the doping concentration ND, the depletion effect can be reduced, and the ionized electrons will compensate the internal electric field which results from the spontaneous polarization. Our results show that an optimum concentration ND exists for which the transition 0.8 eV （1.55 μm） is carried out. Finally, the dependence of the optical absorption α13（ω） on the external electric field and doping concentration is studied. The maximum of the optical absorption can be red-shifted or blue-shifted through varying the doping concentration and the external electric field. The obtained results can be used for designing optical fiber telecommunications operating at 1.55 μm.     

A high order energy preserving scheme for the strongly coupled nonlinear Schrōdinger system

A high order energy preserving scheme for a strongly coupled nonlinear Schrōdinger system is roposed by using the average vector field method. The high order energy preserving scheme is applied to simulate the soliton evolution of the strongly coupled Schrōdinger system. Numerical results show that the high order energy preserving scheme can well simulate the soliton evolution, moreover, it preserves the discrete energy of the strongly coupled nonlinear Schrōdinger system exactly.     

Raman spectrum study of graphite irradiated by swift heavy ions

Highly oriented pyrolytic graphites are irradiated with 40.5-Me V and 67.7-Me V ^112Sn-ions in a wide range of fluences： 1×10^11 ions/cm^2–1×10^14ions/cm^2. Raman spectra in the region between 1200 cm^-1 and 3500cm^-1 show that the disorder induced by Sn-ions increases with ion fluence increasing. However, for the same fluence, the amount of disorder is greater for 40.5-Me V Sn-ions than that observed for 67.7-Me V Sn-ions, even though the latter has a slightly higher value for electronic energy loss. This is explained by the ion velocity effect. Importantly, ～ 3-cm^-1frequency shift toward lower wavenumber for the D band and ～ 6-cm^-1 shift toward lower wavenumber for the 2D band are observed at a fluence of 1×10^14 ions/cm^2, which is consistent with the scenario of radiation-induced strain. The strain formation is interpreted in the context of inelastic thermal spike model, and the change of the 2D band shape at high ion fluence is explained by the accumulation of stacking faults of the graphene layers activated by radiation-induced strain around ion tracks. Moreover,the hexagonal structure around the ion tracks is observed by scanning tunneling microscopy, which confirms that the strains near the ion tracks locally cause electronic decoupling of neighboring graphene layers.