Ranking important nodes in complex networks by simulated annealing
Enhanced electron-positron pair production by frequency chirping in one- and two-color laser pulse fields
Optimal multi-photon entanglement concentration with the photonic Faraday rotation
Round-robin differential quadrature phase-shift quantum key distribution
Probabilistic direct counterfactual quantum communication
Creating nitrogen–vacancy ensembles in diamond for coupling with flux qubit
Pattern dynamics of network-organized system with cross-diffusion
Magnetic phase diagrams of Fe-Mn-Al alloy on the Bethe lattice
Spurious symmetry-broken phase in a bidirectional two-lane ASEP with narrow entrances
As one of the paradigmatic models of non-equilibrium systems, the asymmetric simple exclusion process (ASEP) has been widely used to study many physical, chemical, and biological systems. The ASEP shows a range of nontrivial macroscopic phenomena, among which, the spontaneous symmetry breaking has gained a great deal of attention. Nevertheless, as a basic problem, it has been controversial whether there exist one or two symmetry-broken phases in the ASEP. Based on the mean field analysis and current minimization principle, this paper demonstrates that one of the broken-symmetry phases does not exist in a bidirectional two-lane ASEP with narrow entrances. Moreover, an exponential decay feature is observed, which has been used to predict the phase boundary in the thermodynamic limit. Our findings might be generalized to other ASEP models and thus deepen the understanding of the spontaneous symmetry breaking in non-equilibrium systems.
An image encryption scheme based on three-dimensional Brownian motion and chaotic system
Room temperature NO2-sensing properties of hexagonal tungsten oxide nanorods
Effect of P impurity on NiAlΣ5 grain boundary from first-principles study
Dirac R-matrix calculations of photoionization cross sections of Ni XII and atomic structure data of Ni XIII
The inelastic electron tunneling spectroscopy of edge-modified graphene nanoribbon-based molecular devices
The inelastic electron tunneling spectroscopy (IETS) of four edge-modified finite-size grapheme nanoribbon (GNR)-based molecular devices has been studied by using the density functional theory and Green's function method. The effects of atomic structures and connection types on inelastic transport properties of the junctions have been studied. The IETS is sensitive to the electrode connection types and modification types. Comparing with the pure hydrogen edge passivation systems, we conclude that the IETS for the lower energy region increases obviously when using donor-acceptor functional groups as the edge modification types of the central scattering area. When using donor-acceptor as the electrode connection groups, the intensity of IETS increases several orders of magnitude than that of the pure ones. The effects of temperature on the inelastic electron tunneling spectroscopy also have been discussed. The IETS curves show significant fine structures at lower temperatures. With the increasing of temperature, peak broadening covers many fine structures of the IETS curves. The changes of IETS in the low-frequency region are caused by the introduction of the donor-acceptor groups and the population distribution of thermal particles. The effect of Fermi distribution on the tunneling current is persistent.
Uncertainty evaluation of the isotope shift factors for 2s2p3,1P1o-2s21S0 transitions in B II
Accurate isotope shift factors of the 2s2p 3,1P1-2s21S0 transitions in B II, obtained with the multi-configuration Dirac-Hartree-Fock and the relativistic configuration interaction methods, are reported. We found a linear correlation relation between the mass shift factors and the energies for the transitions concerned, considering all-order electron correlations. This relation is important for estimating the uncertainty in the calculation of isotope shift factors. These atomic data can be used to extract the nuclear mean-square charge radii of the boron isotopes with halo structures or to resolve the high precise spectroscopy of B II in astronomical observation.
MRCI+Q study of the low-lying electronic states of CdF including spin—orbit coupling
Parameter analysis for a nuclear magnetic resonance gyroscope based on bf133Cs-129Xe/131Xe
We theoretically investigate several parameters for the nuclear magnetic resonance gyroscope based on 133Cs-129Xe/131Xe. For a cell containing a mixture of 133Cs at saturated pressure, we investigate the optimal quenching gas (N2) pressure and the corresponding pump laser intensity to achieve 30% 133Cs polarization at the center of the cell when the static magnetic field B0 is 5 μT with different 129Xe/131Xe pressure. The effective field produced by spin-exchange polarized 129Xe or 131Xe sensed by 133Cs can also be discussed in different 129Xe/131Xe pressure conditions. Furthermore, the relationship between the detected signal and the probe laser frequency is researched. We obtain the optimum probe laser detuning from the D2 (62S1/2→62P3/2) resonance with different 129Xe/131Xe pressure owing to the pressure broadening.
Equivalent electron correlations in nonsequential double ionization of noble atoms
Ionization in an intense field considering Coulomb correction
Theoretical study on non-sequential double ionization of carbon disulfide with different bond lengths in linearly polarized laser fields
Controllable optical activity of non-spherical Ag and Co SERS substrate with different magnetic field
Optical potential approach for positron scattering by metastable 23S state of helium
The momentum space coupled channels optical (CCO) method for positron scattering has been extended to study the scattering of positrons by metastable helium for impact energies in the range from the positronium threshold up to high energies. Both the positronium formation and ionization continuum channels are included in the calculations via a complex equivalent local potential. The positronium formation, ionization, elastic and 23S-23P excitation, and total scattering cross sections are all presented and compared with the available information.
Electromagnetic coupling reduction in dual-band microstrip antenna array using ultra-compact single-negative electric metamaterials for MIMO application
Metamaterial beam scanning leaky-wave antenna based on quarter mode substrate integrated waveguide structure
Propagation factor of electromagnetic concentric rings Schell-model beams in non-Kolmogorov turbulence
We derive an analytical expression for the propagation factor (known as M2-factor) of electromagnetic concentric rings Schell-model (EM CRSM) beams in non-Kolmogorov turbulence by utilizing the extended Huygens-Fresnel diffraction integral formula and the second-order moments of the Wigner distribution function (WDF). Our results show that the EM CRSM beam has advantage over the scalar CRSM beam for reducing the turbulence-induced degradation under suitable conditions. The EM CRSM beam with multi-rings far-fields in free space is less affected by the turbulence than the one with dark-hollow far-fields or the electromagnetic Gaussian Schell-model (EGSM) beam. The dependence of the M2-factor on the beam parameters and the turbulence are investigated in detail.
Theoretical investigation of hierarchical sub-wavelength photonic structures fabricated using high-order waveguide-mode interference lithograph
Sub-Rayleigh imaging via undersampling scanning based on sparsity constraints
Probe gain via four-wave mixing based on spontaneously generated coherence
Tunable Nd, La: SrF2 laser and passively Q-switched operation based on gold nanobipyramids saturable absorber
Efficient Nd: YVO4 laser in-band pumped by wavelength-locked 913.9-nm laser diode and Q-switch operation
The influence of stimulated temperature-dependent emission cross section on intracavity optical parametric oscillator
Band gaps structure and semi-Dirac point of two-dimensional function photonic crystals
Tunable optical filter using second-order micro-ring resonator
Degree of polarization based on the three-component pBRDF model for metallic materials
Simplified modeling of frequency behavior in photonic crystal vertical cavity surface emitting laser with tunnel injection quantum dot in active region
Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique
Hot-embossing fabrication of chalcogenide glasses rib waveguide for mid-infrared molecular sensing
Study on shock wave-induced cavitation bubbles dissolution process
This study investigated dissolution processes of cavitation bubbles generated during in vivo shock wave (SW)-induced treatments. Both active cavitation detection (ACD) and the B-mode imaging technique were applied to measure the dissolution procedure of biSpheres contrast agent bubbles by in vitro experiments. Besides, the simulation of SW-induced cavitation bubbles dissolution behaviors detected by the B-mode imaging system during in vivo SW treatments, including extracorporeal shock wave lithotripsy (ESWL) and extracorporeal shock wave therapy (ESWT), were carried out based on calculating the integrated scattering cross-section of dissolving gas bubbles with employing gas bubble dissolution equations and Gaussian bubble size distribution. The results showed that (i) B-mode imaging technology is an effective tool to monitor the temporal evolution of cavitation bubbles dissolution procedures after the SW pulses ceased, which is important for evaluation and controlling the cavitation activity generated during subsequent SW treatments within a treatment period; (ii) the characteristics of the bubbles, such as the bubble size distribution and gas diffusion, can be estimated by simulating the experimental data properly.
Ultra-broadband asymmetric acoustic transmission with single transmitted beam
We report both experimentally and numerically that ultra-broadband asymmetric acoustic transmission is realized by a brass plate and a right triangle reflector immersed in water. This exotic phenomenon arises from the asymmetric excitation of the leaky asymmetric zero-order Lamb mode in the brass plate induced by the incident angle of external bulk waves. The results show that the bandwidth of the asymmetric acoustic transmission could reach 2000 kHz, and the positive transmitted wave is only a single acoustic beam. The device has the advantages of ultra-broadband, single transmitted beam, and simpler structure, which has great potential applications in ultrasonic devices.
Numerical investigation of the interaction of the turbulent dual-jet and acoustic propagation
Effect of electrical discharge in water on concentration of nitrate solution
Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime
Production of a large area diffuse arc plasma with multiple cathode
Lower order three-dimensional Burgers equation having non-Maxwellian ions in dusty plasmas
Detailed calibration of the PI-LCX: 1300 high performance single photon counting hard x-ray CCD camera
High sampling-rate measurement of turbulence velocity fluctuations in Mach 1.8 Laval jet using interferometric Rayleigh scattering
New progress on beam availability and reliability of PKU high intensity CW proton ECR ion source Hot!
The stability and reliability of an ion source and its beam availability are extremely significant for any accelerator, especially for those high current long term CW operation ones like ADS. Although the first high quality 306-hours continuous wave (CW) operating curve at 50 mA@35 keV has been successfully obtained with a standard compact 2.45 GHz ECR ion source at Peking University (PKU), but the uncertainties that caused beam trips before are unacceptable during an accelerator real operation and should be eliminated. Meanwhile, no permission will be given when the beam power is upgraded from 50 mA@35 keV to 50 mA@50 keV. To improve the PKU CW proton source quality, several upgrades were done recently. After those improvements, a new long term CW proton beam experiment at 50 mA@50 keV was carried out in June 2016. The total running time is 300.5 hours, including near 6 hours ion source preparation and 294 hours non-disturb continuous operation. Within the continuous 13 days operation, no beam-off happened, no spark was observed, no beam drop appeared, no interrupting action was needed, and only a few beam fluctuations caused by the air conditional failure occurred. Beam availability and reliability within the 294 hours is 100%. The root-mean-square (RMS) emittance of this 50 mA@50 keV CW proton beam is about 0.186 π.mm.mrad. A careful inspection of the ion source was done after this long term operation and no obvious damage was found. The restart experimental results obtained after the ion source inspection prove the high repeatability of PKU PMECRIS. In addition, a 130-mA H+ beam was obtained at 50 kV with duty factor of 10% (100 Hz/1 ms) with this source. Details will be presented in this paper.
Microwave absorption properties of Ag naowires/carbon black composites
Local microstructural analysis for Y2O3/Eu3+/Mg2+ nanorods by Raman and photoluminescence spectra under high pressure
Irradiation-induced void evolution in iron: A phase-field approach with atomistic derived parameters
Anomalous low-temperature heat capacity in antiperovskite compounds
The low-temperature heat capacities are studied for antiperovskite compounds AXM3 (A=Al, Ga, Cu, Ag, Sn, X=C, N, M=Mn, Fe, Co). A large peak in (C-γT)/T3 versus T is observed for each of a total of 18 compounds investigated, indicating an existence of low-energy phonon mode unexpected by Debye T3 law. Such a peak is insensitive to the external magnetic field up to 80 kOe (1 Oe=79.5775 A·m-1). For compounds with smaller lattice constant, the peak shifts towards higher temperatures with a reduction of peak height. This abnormal peak in (C-γT)/T3 versus T of antiperovskite compound may result from the strongly dispersive acoustic branch due to the heavier A atoms and the optical-like mode from the dynamic rotation of XM6 octahedron. Such a low-energy phonon mode may not contribute negatively to the normal thermal expansion in AXM3 compounds, while it is usually concomitant with negative thermal expansion in open-structure material (e.g., ZrW2O8, ScF3).
Orbital electronic heat capacity of hydrogenated monolayer and bilayer graphene
Novel high-K with low specific on-resistance high voltage lateral double-diffused MOSFET
Structural, electronic, optical, and magnetic properties of Co-doped Cu2O
Structural, electronic, and magnetic properties of vanadium atom-adsorbed MoSe2 monolayer
Using the first-principles calculations, we study the structural, electronic, and magnetic properties of vanadium adsorbed MoSe2 monolayer, and the magnetic couplings between the V adatoms at different adsorption concentrations. The calculations show that the V atom is chemically adsorbed on the MoSe2 monolayer and prefers the location on the top of an Mo atom surrounded by three nearest-neighbor Se atoms. The interatomic electron transfer from the V to the nearest-neighbor Se results in the polarized covalent bond with weak covalency, associated with the hybridizations of V with Se and Mo. The V adatom induces local impurity states in the middle of the band gap of pristine MoSe2, and the peak of density of states right below the Fermi energy is associated with the V-dz2 orbital. A single V adatom induces a magnetic moment of 5 μB that mainly distributes on the V-3d and Mo-4d orbitals. The V adatom is in high-spin state, and its local magnetic moment is associated with the mid-gap impurity states that are mainly from the V-3d orbitals. In addition, the crystal field squashes a part of the V-4s electrons into the V-3d orbitals, which enhances the local magnetic moment. The magnetic ground states at different adsorption concentrations are calculated by generalized gradient approximations (GGA) and GGA+U with enhanced electron localization. In addition, the exchange integrals between the nearest-neighbor V adatoms at different adsorption concentrations are calculated by fitting the first-principle total energies of ferromagnetic (FM) and antiferromagnetic (AFM) states to the Heisenberg model. The calculations with GGA show that there is a transition from ferromagnetic to antiferromagnetic ground state with increasing the distance between the V adatoms. We propose an exchange mechanism based on the on-site exchange on Mo and the hybridization between Mo and V, to explain the strong ferromagnetic coupling at a short distance between the V adatoms. However, the ferromagnetic exchange mechanism is sensitive to both the increased inter-adatom distance at low concentration and the enhanced electron localization by GGA+U, which leads to antiferromagnetic ground state, where the antiferromagnetic superexchange is dominant.
Temperature and hydrogen-like impurity effects on the excited state of the strong coupling bound polaron in a CsI quantum pseudodot
With hydrogen-like impurity (HLI) located in the center of CsI quantum pseudodot (QPD) and by using the variational method of Pekar type (VMPT), we investigate the first-excited state energy (FESE), excitation energy and transition frequency of the strongly-coupled bound polaron in the present paper. Temperature effects on bound polaron properties are calculated by employing the quantum statistical theory (QST). According to the present work's numerical results, the FESE, excitation energy and transition frequency decay (amplify) with raising temperature in the regime of lower (higher) temperature. They are decreasing functions of Coulomb impurity potential strength.
On the reverse leakage current of Schottky contacts on free-standing GaN at high reverse biases
Photon-assisted and spin-dependent shot noise in magnetic-field tunable ZnSe/Zn1-xMnxSe structures
Effect of metal catalyst on the mechanism of hydrogen spillover in three-dimensional covalent-organic frameworks
Impact of coupling geometry on thermoelectric properties of oligophenyl-base transistor
Enhancement of subgap conductance in a graphene superconductor junction by valley polarization
Ballistic transport and quantum interference in InSb nanowire devices Hot!
An experimental realization of a ballistic superconductor proximitized semiconductor nanowire device is a necessary step towards engineering topological quantum electronics. Here, we report on ballistic transport in InSb nanowires grown by molecular-beam epitaxy contacted by superconductor electrodes. At an elevated temperature, clear conductance plateaus are observed at zero magnetic field and in agreement with calculations based on the Landauer formula. At lower temperature, we have observed characteristic Fabry-Pérot patterns which confirm the ballistic nature of charge transport. Furthermore, the magnetoconductance measurements in the ballistic regime reveal a periodic variation related to the Fabry-Pérot oscillations. The result can be reasonably explained by taking into account the impact of magnetic field on the phase of ballistic electron's wave function, which is further verified by our simulation. Our results pave the way for better understanding of the quantum interference effects on the transport properties of InSb nanowires in the ballistic regime as well as developing of novel device for topological quantum computations.
Thermal stability and electrical transport properties of Ge/Sn-codoped single crystalline β-Zn4Sb3 prepared by the Sn-flux method
This study prepares a group of single crystalline β-Zn4Sb3 with Ge and Sn codoped by the Sn-flux method according to the nominal stoichiometric ratios of Zn4.4Sb3GexSn3 (x=0-0.15). The prepared samples possess a metallic luster surface with perfect appearance and large crystal sizes. The microscopic cracks or defects are invisible in the samples from the back-scattered electron image. Except for the heavily Ge-doped sample of x=0.15, all the samples are single phase with space group R3c. The thermal analysis results show that the samples doped with Ge exhibit an excellent thermal stability. Compared with the polycrystalline Ge-substituted β-Zn4Sb3, the present single crystals have higher carrier mobility, and hence the electrical conductivity is improved, which reaches 7.48×104 S·m-1 at room temperature for the x=0.1 sample. The change of Ge and Sn contents does not improve the Seebeck coefficient significantly. Benefiting from the increased electrical conductivity, the sample with x=0.075 gets the highest power factor of 1.45×10-3 W·m-1·K-2 at 543 K.
Electronic structures and magnetic properties of Zn- and Cd-doped AlN nanosheets: A first-principles study
Study of magnetic and optical properties of Zn1-xTMxTe (TM=Mn, Fe, Co, Ni) diluted magnetic semiconductors: First principle approach
Crystallization behaviors of ultrathin Al-doped HfO2 amorphous films grown by atomic layer deposition
In this work, ultrathin pure HfO2 and Al-doped HfO2 films (about 4-nm thick) are prepared by atomic layer deposition and the crystallinities of these films before and after annealing at temperatures ranging from 550℃ to 750℃ are analyzed by grazing incidence x-ray diffraction. The as-deposited pure HfO2 and Al-doped HfO2 films are both amorphous. After 550-℃ annealing, a multiphase consisting of a few orthorhombic, monoclinic and tetragonal phases can be observed in the pure HfO2 film while the Al-doped HfO2 film remains amorphous. After annealing at 650℃ and above, a great number of HfO2 tetragonal phases, a high-temperature phase with higher dielectric constant, can be stabilized in the Al-doped HfO2 film. As a result, the dielectric constant is enhanced up to about 35. The physical mechanism of the phase transition behavior is discussed from the viewpoint of thermodynamics and kinetics.
Semipolar (1122) and polar (0001) InGaN grown on sapphire substrate by using pulsed metal organic chemical vapor deposition
The magnetic properties and magnetocaloric effects in binary R-T (R=Pr, Gd, Tb, Dy, Ho, Er, Tm; T=Ga, Ni, Co, Cu) intermetallic compounds
In this paper, we review the magnetic properties and magnetocaloric effects (MCE) of binary R-T (R=Pr, Gd, Tb, Dy, Ho, Er, Tm; T=Ga, Ni, Co, Cu) intermetallic compounds (including RGa series, RNi series, R12Co7 series, R3Co series and RCu2 series), which have been investigated in detail in the past several years. The R-T compounds are studied by means of magnetic measurements, heat capacity measurements, magnetoresistance measurements and neutron powder diffraction measurements. The R-T compounds show complex magnetic transitions and interesting magnetic properties. The types of magnetic transitions are investigated and confirmed in detail by multiple approaches. Especially, most of the R-T compounds undergo more than one magnetic transition, which has significant impact on the magnetocaloric effect of R-T compounds. The MCE of R-T compounds are calculated by different ways and the special shapes of MCE peaks for different compounds are investigated and discussed in detail. To improve the MCE performance of R-T compounds, atoms with large spin (S) and atoms with large total angular momentum (J) are introduced to substitute the related rare earth atoms. With the atom substitution, the maximum of magnetic entropy change (Δ SM), refrigerant temperature width (Twidth) or refrigerant capacity (RC) is enlarged for some R-T compounds. In the low temperature range, binary R-T (R=Pr, Gd, Tb, Dy, Ho, Er, Tm; T=Ga, Ni, Co, Cu) intermetallic compounds (including RGa series, RNi series, R12Co7 series, R3Co series and RCu2 series) show excellent performance of MCE, indicating the potential application for gas liquefaction in the future.
Photoconductive multi-layer graphene photodetectors fabricated on etched silicon-on-insulator substrates
Electrical and dielectric characterization of Au/ZnO/n—Si device depending frequency and voltage
Geometrically induced π-band splitting in graphene superlattices
Investigation on latch-up susceptibility induced by high-power microwave in complementary metal-oxide-semiconductor inverter
Improvement of the carrier distribution with GaN/InGaN/AlGaN/InGaN/GaN composition-graded barrier for InGaN-based blue light-emitting diode
Spin transfer torque in the semiconductor/ferromagnetic structure in the presence of Rashba effect
Shifting curves based on the detector integration effect for x-ray phase contrast imaging
Highly conductive and transparent carbon nanotube-based electrodes for ultrathin and stretchable organic solar cells Hot!
In this work, we have presented a freestanding and flexible CNT-based film with sheet resistance of 60 Ω/□ and transmittance of 82% treated by nitric acid and chloroauric acid in sequence. Based on modified CNT film as a transparent electrode, we have demonstrated an ultrathin, flexible organic solar cell (OSC) fabricated on 2.5-μm PET substrate. The efficiency of OSC, combined with a composite film of poly (3-hexylthiophene) (P3HT) and phenyl-C61 butyric acid methyl ester (PCBM) as an active layer and with a thin layer of methanol soluble biuret inserted between the photoactive layer and the cathode, can be up to 2.74% which is approximate to that of the reference solar cell fabricated with ITO-coated glass (2.93%). Incorporating the as-fabricated ITO-free OSC with pre-stretched elastomer, 50% compressive deformation can apply to the solar cells. The results show that the as-prepared CNT-based hybrid film with outstanding electrical and optical properties could serve as a promising transparent electrode for low cost, flexible and stretchable OSCs, which will broaden the applications of OSC and generate more solar power than it now does.
Performance improvement of continuous carbon nanotube fibers by acid treatment
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h, based on an improved chemical vapor deposition method. As-prepared fibers are further post-treated by acid. According to the SEM images and Raman spectra, the acid treatment results in the compaction and surface modification of the CNTs in fibers, which are beneficial for the electron and load transfer. Compared to the HNO3 treatment, HClSO3 or H2SO4 treatment is more effective for the improvement of the fibers' properties. After HClSO3 treatment for 2 h, the fibers' strength and electrical conductivity reach up to ~2 GPa and ~4.3 MS/m, which are promoted by ~200% and almost one order of magnitude than those without acid treatment, respectively. The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G' band and the strain transfer factor of the fibers under tension. The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength. With the HClSO3 treatment, the strain transfer factor is enhanced from ~3.9% to ~53.6%.
Simulation design of P-I-N-type all-perovskite solar cells with high efficiency
According to the good charge transporting property of perovskite, we design and simulate a p-i-n-type all-perovskite solar cell by using one-dimensional device simulator. The perovskite charge transporting layers and the perovskite absorber constitute the all-perovskite cell. By modulating the cell parameters, such as layer thickness values, doping concentrations and energy bands of n-, i-, and p-type perovskite layers, the all-perovskite solar cell obtains a high power conversion efficiency of 25.84%. The band matched cell shows appreciably improved performance with widen absorption spectrum and lowered recombination rate, so weobtain a high Jsc of 32.47 mA/cm2. The small series resistance of the all-perovskite solar cell also benefits the high Jsc. The simulation provides a novel thought of designing perovskite solar cells with simple producing process, low production cost and high efficient structure to solve the energy problem.
Scaling of weighted spectral distribution in weighted small-world networks
Effect of air breakdown on microwave pulse energy transmission