mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
An ultrathin wide-band planar metamaterial absorber based on a fractal frequency selective surface and resistive film

We propose an ultrathin wide-band metamaterial absorber(MA) based on a Minkowski(MIK) fractal frequency selective surface and resistive film.This absorber consists of a periodic arrangement of dielectric substrates sandwiched with an MIK fractal loop structure electric resonator and a resistive film.The finite element method is used to simulate and analyze the absorption of the MA.Compared with the MA-backed copper film,the designed MA-backed resistive film exhibits an absorption of 90% at a frequency region of 2 GHz-20 GHz.The power loss density distribution of the MA is further illustrated to explain the mechanism of the proposed MA.Simulated absorptions at different incidence cases indicate that this absorber is polarization-insensitive and wide-angled.Finally,further simulated results indicate that the surface resistance of the resistive film and the dielectric constant of the substrate can affect the absorbing property of the MA.This absorber may be used in many military fields
A first-principles study of the structural and elastic properties of orthorhombic and tetragonal Ca_3Mn_2O_7

The structural and elastic properties of multiferroic Ca_3Mn_2O_7 with ferroelectric orthorhombic(O-phase) and paraelectric tetragonal structures(T-phase) have been studied by first-principles calculations within the generalized gradient approximation(GGA) and the GGA plus Hubbard U approaches(GGA+U).The calculated theoretical structures are in good agreement with the experimental values.The T-phase is found to be antiferromagnetic(AFM) and the AFM O-phase is more stable than the T-phase,which also agree with the experiments.On these bases,the single-crystal elastic constants(C_(ij) s) and elastic properties of polycrystalline aggregates are investigated for the two phases.Our elasticity calculations indicate Ca_3Mn_2O_7 is mechanically stable against volume expansions.The AFM O-phase is found to be a ductile material,while the AFM T-phase shows brittle nature and tends to be elastically isotropic.We also investigate the influence of strong correlation effects on the elastic properties,qualitatively consistent results are obtained in a reasonable range of values of U.Finally,the ionicity is discussed by Bader analysis.Our work provides useful guidance for the experimental elasticity measurements of Ca_3Mn_2O_7,and makes the strain energy calculation in multiferroic Ca_3Mn_2O_7 thin films possible
Relativistic symmetries with the trigonometric Poschl-Teller potential plus Coulomb-like tensor interaction

The Dirac equation is solved to obtain its approximate bound states for a spin-1/2 particle in the presence of trigonometric Poschl-Teller(tPT) potential including a Coulomb-like tensor interaction with arbitrary spin-orbit quantum number κ using an approximation scheme to substitute the centrifugal terms κ(κ± 1)r~(-2).In view of spin and pseudo-spin(p-spin) symmetries,the relativistic energy eigenvalues and the corresponding two-component wave functions of a particle moving in the field of attractive and repulsive tPT potentials are obtained using the asymptotic iteration method(AIM).We present numerical results in the absence and presence of tensor coupling A and for various values of spin and p-spin constants and quantum numbers n and κ.The non-relativistic limit is also obtained
New operator identities with regard to the two-variable Hermite polynomial by virtue of entangled state representation

By virtue of the entangled state representation we concisely derive some new operator identities with regard to the two-variable Hermite polynomial(TVHP).By them and the technique of integration within an ordered product(IWOP) of operators we further derive new generating function formulas of the TVHP.They are useful in quantum optical theoretical calculations.It is seen from this work that by combining the IWOP technique and quantum mechanical representations one can derive some new integration formulas even without really performing the integration
First-principles study of electronic properties of interfacial atoms in metal-metal contact electrification

The mechanism of contact electrification between metals was studied using the first-principles method, taking the Ag-Fe contact as an example. Charge population, charge density difference, the orbitals and densities of states (DOS) were calculated to study the electronic properties of the contacting interfacial atoms. Based on the calculation, the amount of contact charge was obtained. The investigation revealed that the electrons near Fermi levels with higher energies transfer between the outermost orbitals (s orbitals for Ag and d orbitals for Fe). Meanwhile, polarized covalent bonds form between the d electrons in the deep energy states. These two effects together lead to an increase of charge magnitude at the interface. Also, the electrons responsible for electrification can be determined by their energies and orbitals
Feedback control of wave segments in an excitable medium

Depending on the excitability of the medium, a propagating wave segment will either contract or expand to fill the medium with spiral waves. This paper aims to introduce a simple mechanism of feedback control to stabilize such an expansion or contraction. To do this, we lay out a feedback control system in a block diagram and reduce it into a bare, universal formula. Analytical and experimental findings are compared through a series of numerical simulations of the Barkley model
Superposition solitons in two-component Bose-Einstein condensates

We develop the Hirota bilinear method and obtain the exact one and two superposition soliton solutions for two-component Bose-Einstein condensates. The conversion of three kinds of solitons including the superposition solitons, bright-bright solitons, and dark-bright solitons is discussed. With the energy analysis, we find that the superposition soliton state is an excitation state for this system. Moreover, the collision of two superposition solitons is found to be elastic
Dual-gate lateral double-diffused metal—oxide semiconductor with ultra-low specific on-resistance

A new high voltage trench lateral double-diffused metal-oxide semiconductor (LDMOS) with ultra-low specific onresistance (R_(on,sp) ) is proposed. The structure features a dual gate (DG LDMOS): a planar gate and a trench gate inset in the oxide trench. Firstly, the dual gate can provide a dual conduction channel and reduce R_(on,sp) dramatically. Secondly, the oxide trench in the drift region modulates the electric field distribution and reduces the cell pitch but still can maintain comparable breakdown voltage (BV). Simulation results show that the cell pitch of the DG LDMOS can be reduced by 50% in comparison with that of conventional LDMOS at the equivalent BV; furthermore, R_(on,sp) of the DG LDMOS can be reduced by 67% due to the smaller cell pitch and the dual gate
Backstepping-based lag synchronization of a complex permanent magnet synchronous motor system

Through introducing the concept of complex current and resetting cross-coupling term, this paper proposes a novel complex permanent magnet synchronous motor system and analyzes its properties. Based on a complex permanent magnet synchronous motor system, we design controllers and achieve lag synchronizations both in real part and imaginary part with backstepping method. In our study, we take complex current, time delay, and structure of complex system into consideration. Numerical simulation results demonstrate the validity of controllers
Engineering of electronic and optical properties of ZnO thin films via Cu doping

ZnO thin films doped with different Cu concentrations are fabricated by reactive magnetron sputtering technique. XRD analysis indicates that the crystal quality of the ZnO:Cu film can be enhanced by a moderate level of Cu-doping in the sputtering process. The results of XPS spectra of zinc, oxygen, and copper elements show that Cu-doping has an evident and complicated effect on the chemical state of oxygen, but little effect on those of zinc and copper. Interestingly, further investigation of the optical properties of ZnO:Cu samples shows that the transmittance spectra exhibit both red shift and blue shift with the increase of Cu doping, in contrast to the simple monotonic behavior of the Burstein–Moss effect. Analysis reveals that this is due to the competition between oxygen vacancies and intrinsic and surface states of oxygen in the sample. Our result may suggest an effective way of tuning the bandgap of ZnO samples
Influence of Schottky drain contacts on the strained AlGaN barrier layer of AlGaN/AlN/GaN heterostructure field-effect transistors

Rectangular Schottky drain AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with different gate contact areas and conventional AlGaN/AlN/GaN HFETs as control were both fabricated with same size. It was found there is a significant difference between Schottky drain AlGaN/AlN/GaN HFETs and the control group both in drain series resistance and in two-dimensional electron gas (2DEG) electron mobility in the gate-drain channel. We attribute this to the different influence of Ohmic drain contacts and Schottky drain contacts on the strained AlGaN barrier layer. For conventional AlGaN/AlN/GaN HFETs, annealing drain Ohmic contacts gives rise to a strain variation in the AlGaN barrier layer between the gate contacts and the drain contacts, and results in strong polarization Coulomb field scattering in this region. In Schottky drain AlGaN/AlN/GaN HFETs, the strain in the AlGaN barrier layer is distributed more regularly
Structural changes concurrent with ferromagnetic transition

Ferromagnetic transition has generally been considered to involve only an ordering of magnetic moment with no change in the host crystal structure or symmetry, as evidenced by a wealth of crystal structure data from conventional X-ray diffractometry (XRD). However, the existence of magnetostriction in all known ferromagnetic systems indicates that the magnetic moment is coupled to the crystal lattice; hence there is a possibility that magnetic ordering may cause a change in crystal structure. With the development of high-resolution synchrotron XRD, more and more magnetic transitions have been found to be accompanied by simultaneous structural changes. In this article, we review our recent progress in understand- ing the structural change at a ferromagnetic transition, including synchrotron XRD evidence of structural changes at the ferromagnetic transition, a phenomenological theory of crystal structure changes accompanying ferromagnetic transitions, new insight into magnetic morphotropic phase boundaries (MPB) and so on. Two intriguing implications of non-centric symmetry in the ferromagnetic phase and the first-order nature of ferromagnetic transition are also discussed here. In short, this review is intended to give a self-consistent and logical account of structural change occurring simultaneously with a ferromagnetic transition, which may provide new insight for developing highly magneto-responsive materials
Efficient generation of two-dimensional cluster states in a cavity QED

We propose a scheme to achieve a kind of nontrivial multipartite pair-wise controlled phase operation in a cavity QED setup. The operation implemented is of geometrical nature and is not sensitive to the thermal state of the cavity. In particular, we have managed to avoid the conventional dispersive coupling so that high speed gate operation is achieved which is very important in view of decoherence. We show that this multipartite pair-wise controlled phase operation makes the generation of two-dimensional cluster states very efficient
Enhanced optical absorption by Ag nanoparticles in a thin film Si solar cell

Thin film solar cells have the potential to significantly reduce the cost of photovoltaics. Light trapping is crucial to such a thin film silicon solar cell because of a low absorption coefficient due to its indirect band gap. In this paper, we investigate the suitability of surface plasmon resonance Ag nanoparticles for enhancing optical absorption in the thin film solar cell. For evaluating the transmittance capability of Ag nanoparticles and the conventional antireflection film, an enhanced transmittance factor is introduced. We find that under the solar spectrum AM1.5, the transmittance of Ag nanoparticles with radius over 160 nm is equivalent to that of conventional textured antireflection film, and its effect is better than that of the planar antireflection film. The influence of the surrounding medium is also discussed
Controlled remote implementation of quantum operations with high-dimensional systems

We present two protocols for the controlled remote implementation of quantum operations between three-party high-dimensional systems. Firstly, the controlled teleportation of an arbitrary unitary operation by bidirectional quantum state teleportaion (BQST) with high-dimensional systems is considered. Then, instead of using the BQST method, a protocol for controlled remote implementation of partially unknown operations belonging to some restricted sets in high-dimensional systems is proposed. It is shown that, in these protocols, if and only if the controller would like to help the sender with the remote operations, the controlled remote implementation of quantum operations for high-dimensional systems can be completed
A theoretical and experimental study on all-normal-dispersion Yb-doped mode-locked fiber lasers

We report on a theoretical and experimental study of an all-normal-dispersion (ANDi) Yb-doped mode-locked fiber laser, in which nonlinear polarization rotation (NPR) is used to realize mode-locking without any dispersion compensation. Based on the coupled nonlinear Schrodinger (CNLS) equation, a model simulating the mode-locked process of an allnormal-dispersion ring fiber laser is developed, which shows that the achievement of stable mode-locking depends on the alignment of the polarization controller (PC) along the fast-polarization axis of the fiber, the birefringence intensity, and the net cavity dispersion. According to the theoretical analysis, stable mode-locked pulses with pulse duration 300 ps and average output power 33.9mW at repetition rate 36MHz are obtained
Effect of microstructure on the thermoelectric properties of CSD-grown Bi_2Sr_2Co_2O_y thin films

Three Bi_2Sr_2Co_2O_y thin films with different microstructures have been prepared by chemical solution deposition on LaAlO_3(001) through varying the annealing temperature.With the decrease in the annealing temperature,both the size and c-axis alignment degree of grains in the film decrease as well,leading to an increase in the film resistivity.In addition,the decrease in the annealing temperature also results in a slight increase in the Seebeck coefficient due to the enhanced energy filtering effect of the small-grain film.The nanostructured Bi_2Sr_2Co_2O_y film with an average grain size of about 100 nm shows a power factor comparable to that of films with larger grains.Since the thermal conductivity of the nanostructured films can be depressed due to the enhanced phonon scattering by grain boundary,a higher figure of merit is expected in Bi_2Sr_2Co_2O_y thin film with grains in nanometer size
The effective ionization coefficients and electron drift velocities in gas mixtures of CF_3I with N_2 and CO_2 obtained from Boltzmann equation analysis

The electron swarm parameters including the density-normalized effective ionization coefficients(α-η)/N and the electron drift velocities V e are calculated for a gas mixture of CF_3I with N_2 and CO_2 by solving the Boltzmann equation in the condition of a steady-state Townsend(SST) experiment.The overall density-reduced electric field strength is from 100 Td to 1000 Td(1 Td = 10~(-17)V?cm~2),while the CF_3I content k in the gas mixture can be varied over the range from 0% to 100%.From the variation of(αη)/N with the CF_3I mixture ratio k,the limiting field strength(E/N)_( lim) for each CF_3I concentration is derived.It is found that for the mixtures with 70% CF_3I,the values of(E/N)_( lim) are essentially the same as that for pure SF_6.Additionally,the global warming potential(GWP) and the liquefaction temperature of the gas mixtures are also taken into account to evaluate the possibility of application in the gas insulation of power equipment
Induced modification of the geometric phase of a qubit coupled to an XY spin chain by Dzyaloshinsky-Moriya interaction

We consider a qubit symmetrically and transversely coupled to an XY spin chain with Dzyaloshinsky-Moriya(DM) interaction in the presence of a transverse magnetic field.An analytical expression for the geometric phase of the qubit is obtained in the weak coupling limit.We find that the modification of the geometrical phase induced by the spin chain environment is greatly enhanced by DM interaction in the weak coupling limit around the quantum phase transition point of the spin chain
Discussion of the metric in characterizing the single-event effect induced by heavy ions

The single-event effect(SEE) is the most serious problem in space environment.The modern semiconductor technology is concerned with the feasibility of the linear energy transfer(LET) as metric in characterizing SEE induced by heavy ions.In this paper,we calibrate the detailed static random access memory(SRAM) cell structure model of an advanced field programmable gate array(FPGA) device using the computer-aided design tool,and calculate the heavy ion energy loss in multi-layer metal utilizing Geant4.Based on the heavy ion accelerator experiment and numerical simulation,it is proved that the metric of LET at the device surface,ignoring the top metal material in the advanced semiconductor device,would underestimate the SEE.In the SEE evaluation in space radiation environment the top-layers on the semiconductor device must be taken into consideration
Hydrothermal synthesis of hexagonal-phase NaYF_4:Er,Yb with different shapes for application as photovoltaic up-converters

Hexagonal β-NaYF_4 co-doped with Yb~(3+) and Er~(3+) is directly synthesized under mild conditions using a hydrothermal method.The variation of the ratio of Ln~(3+) to F-and ethylenediaminetetraacetic acid(EDTA) causes the shape of the microcrystal to change from microplate to microcolumn.The NaYF_4 powder is mixed with polydimethylsiloxane(PDMS) to create an up-converter for thin film amorphous silicon solar cells so as to evaluate the effectiveness of the synthesized material as an up-converter.In order to overcome the difficulty in measuring the effectiveness of up-conversion material,a new method of using near infrared illumination to measure the short circuit current densities of solar cells both with and without up-converters is developed.An up-converter with pure hexagonal NaYF_4:Yb~(3+)/Er~(3+) microcrystal produces a high current output.Emission intensity data obtained by photoluminescence suggest that pure hexagonal NaYF_4:Yb~(3+)/Er~(3+) microcrystals are more efficient than nanocrystals when used as up-converting phosphors
Transport through artificial single-molecule magnets:Spin-pair state sequential tunneling and Kondo effects

The transport properties of an artificial single-molecule magnet based on a CdTe quantum dot doped with a single Mn~(+2) ion(S=5/2) are investigated by the non-equilibrium Green function method.We consider a minimal model where the Mn-hole exchange coupling is strongly anisotropic so that spin-flip is suppressed and the impurity spin S and a hole spin s entering the quantum dot are coupled into spin pair states with(2S+1) sublevels.In the sequential tunneling regime,the differential conductance exhibits(2S+1) possible peaks,corresponding to resonance tunneling via(2S+1) sublevels.At low temperature,Kondo physics dominates transport and(2S+1) Kondo peaks occur in the local density of states and conductance.These peaks originate from the spin-singlet state formed by the holes in the leads and on the dot via higher-order processes and are related to the parallel and antiparallel spin pair states
Total cross sections for electron scattering from sulfur compounds

The original additivity rule method cannot give good results for electron scattering from SO,SO_2,SO_2Cl_2,SO_2ClF,and SO_2F_2 molecules at low energy,because the electron-molecule scattering is simply reduced to electron-atom scattering.Considering the difference between the bound atom in a molecule and the corresponding free atom,the original additivity rule is revised.With the revised additivity rule,the total cross sections for electron scattering from these molecules are calculated over a wide energy range below 3000 eV and compared with the available experimental and theoretical data.A better agreement between them is obtained
Structured mirror array for two-dimensional collimation of a chromium beam in atom lithography

Direct-write atom lithography,one of the potential nanofabrication techniques,is restricted by some difficulties in producing optical masks for the deposition of complex structures.In order to make further progress,a structured mirror array is developed to transversely collimate the chromium atomic beam in two dimensions.The best collimation is obtained when the laser red detunes by natural line-width of transition ~7S_3 → ~7P_4~0 of the chromium atom.The collimation ratio is 0.45 vertically(in x axis),and it is 0.55 horizontally(in y axis).The theoretical model is also simulated,and success of our structured mirror array is achieved
Asymptotic dynamics of the alternate degrees of freedom for a two-mode system:An analytically solvable model

The composite systems can be non-uniquely decomposed into parts(subsystems).Not all decompositions(structures) of a composite system are equally physically relevant.In this paper we answer on theoretical ground why it may be so.We consider a pair of mutually un-coupled modes in the phase space representation that are subjected to the independent quantum amplitude damping channels.By investigating asymptotic dynamics of the degrees of freedom,we find that the environment is responsible for the structures non-equivalence.Only one structure is distinguished by both locality of the environmental influence on its subsystems and a classical-like description
A cellular automata traffic flow modeling of desired speed variability

The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maximal velocity. However, the behavior of the satisfaction rate as a function of the coefficient of variance is independent of the maximal velocity. This is in good agreement with empirical results obtained by Lipshtat [Phys. Rev. E 79 066110 (2009)]. Furthermore, our numerical result demonstrates that at low density the satisfaction rate takes higher values, whereas the coefficient of variance is close to zero. The coefficient of variance increases with increasing density, while the satisfaction rate decreases to zero. Moreover, we have also shown that, at low density the coefficient variance depends strongly on the probability of overtaking