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The coercivity and grain size of equiatomic FePt alloy films annealed at 500 and 600 °C with different magnetic fields of 0–70 kOe have been investigated. It is found that applying a magnetic field with appropriate strength during postdeposition annealing not only enhances the coercivity but also reduces the grain size of the FePt films. Measurements of the microstructure and magnetic properties of the FePt films reveal that the coercivity is affected by both the ordered volume fraction and a microstructure factor that is related to the ordered volume fraction. The high coercivity in FePt films annealed with an appropriate strength of magnetic field is due to an increasing density of magnetic domain wall pinning sites concurrent with an increasing fraction of the ordered phase. [ABSTRACT FROM AUTHOR]

Currently, the focus of stochastic resonance (SR) research is primarily on bistable systems, and classical bistable SR systems have the problems of low dimension, inconvenient parameter adjustment, and high threshold for SR effects. In this paper, based on the classic bistable system, a class of multi-dimensional single potential well SR systems without transition threshold is proposed and applied to signal processing. Firstly, the mechanism of double potential well SR and single potential well SR is studied. On this basis, a kind of multi-dimensional single potential well SR system is defined and its theoretical conditions are analyzed. Then a specific four-dimensional single potential well SR system is constructed, and the dynamics of the system is analyzed. The gain range and the approximate relationship between the system input and the four-dimensional output are derived. Finally, the four-dimensional single potential well SR system is applied to the processing of various signals. The experimental results show that the constructed system has good noise reduction and feature amplification effects on noisy signals through the advantages of multi-dimensional output, and can be used to highlight the fault feature frequency in bearing fault signals. [ABSTRACT FROM AUTHOR]

We demonstrate that by spatially modulating the Bessel optical lattice where a Bose-Einstein condensate is loaded, we get tunable rotary orbits of nonlinear lattice modes. We show that the radially expanding or shrinking Bessel lattice can drag the nonlinear localized modes to orbits of either larger or smaller radii and the rotary velocity of nonlinear modes can be changed accordingly. The localized modes can even be transferred to the Bessel lattice core when the localized modes' rotations are stopped. Effects beyond the quasi-particle approximation such as destruction of the nonlinear modes by nonadiabatic dragging are also explored. [ABSTRACT FROM AUTHOR]

The aim of this work is to propose a novel magneto-rheological (MR) braking system (MRBS) using a magneto-rheological brake (MRB) and evaluate its anti-lock braking performance by theoretical analysis, numerical simulation and experimental verification. Firstly, the linear control mathematical model of the MRB is derived by the operation principle of the MR effect and the structure size of the MRB. Secondly, four different anti-lock braking controllers are designed for the MRBS to analyse the control performance under various road conditions. Subsequently, a flywheel type 1/4 vehicle antilock braking system test bench is established for investigates the antilock braking performance of the MRBS. The simulation results demonstrate that the road recognition based fuzzy proportional integral derivative (RRBF-PID) controller can maximize the utilization of the road adhesion coefficient. Furthermore, the RRBF-PID controller can shorten the braking time and distance, as well as maintain the stability of the braking direction during the braking process. In this work, the MRBS exhibits a satisfactory antilock braking performance under different road conditions and the research results could provide a reliable theoretical and experimental basis for the MRBS. [ABSTRACT FROM AUTHOR]

We investigate the voltage-controlled magnetism effect of HfZrO/CoFeB hybrid film and a Hall device with perpendicular magnetic anisotropy. The magnetization versus magnetic field experiments and anomalous Hall experiments before and after applying voltage are performed. The results exhibit that the coercive field of samples remain unchanged while the saturation magnetization shows a permanent increase (more than 60%), which is regardless of the direction of applied voltage. Different from conventional voltage-controlled magnetic anisotropy, in our work, only the saturation magnetization is enhanced by the applied voltage without trading off other magnetic parameters of CoFeB. Thus, such a finding proposes a more efficient voltage-controlled method to achieve a magnetic memory device with high thermal stability, high tunnel magnetoresistance and low switching current for magneto-resistive random-access memory under scaling beyond 2X nm. [ABSTRACT FROM AUTHOR]

Single Event Gate Rupture (SEGR) is one of the most severe problems that SiC MOSFETs experience in the space radiation environment. The influence of drain bias (V DS) and gate bias (V GS) on SEGR was explored in this work using the fluctuation of leakage current when the device was irradiated at various biases. The source of leakage current is isolated and determined through testing, and the influence mechanisms of V GS and V DS effects on SEGR are further explored using TCAD simulation. The investigation demonstrates that while the drain bias can indirectly enhance the potential of SiC-side oxide, the gate bias can directly alter the potential of metal-side oxide during heavy ion irradiation. When gate bias and drain bias are combined, a strong electric field is generated in the gate oxide, resulting in SEGR in SiC MOSFETs. In addition to single event burnout, the SEGR effect is a significant issue for SiC MOSFETs due to their high susceptibility to heavy ion irradiation. [ABSTRACT FROM AUTHOR]

ZnO quantum dots sensitized SnO2 porous nanowires were fabricated and designed for UV excitation gas sensor. The ZnO/SnO2 composite (SZQ1%) with the molar proportion of 1:100 exhibits excellent sensing properties to NO2 gas under UV irradiation at 40 °C. The limits of detection of the SZQ1% sensor is 100 ppb. The humidity stability of SZQ1% was also measured and discussed by DC reversed circuit and complex impedance curves. The gas sensing mechanism is well discussed and illustrated to the ZnO quantum dots sensitized and the increased photo-generated carriers under UV irradiation. [ABSTRACT FROM AUTHOR]

Recently, metallic 1T MoS2 has been investigated due to its excellent performance in electrocatalysts, photocatalysts, supercapacitors and secondary batteries. However, there are only a few fabrication methods to synthesize stable 1T MoS2. In this work, exfoliated MoS2 is employed as seed crystals for the nucleation and growth of a stable 1T MoS2 grains by an epitaxial growth strategy. The 1T MoS2 displays a large interlayer spacing around 0.95 nm, excellent hydrophilia and more electrochemically active sites along the basal plane, which contribute an efficient ion/electron transport pathway and structural stability. When employed as the anode material for sodium ion batteries, the 1T MoS2 electrodes can survive 500 full charge/discharge cycles with a minimum capacity loss of 0.40 mAh gâˆ'1 cycleâˆ'1 tested at a current density of 1.0 A gâˆ'1, and the capacity degradation is as low as 0.39 mAh gâˆ'1 cycleâˆ'1 at a current density of 2.0 A gâˆ'1. [ABSTRACT FROM AUTHOR]

Widespread concern has been attached to the frequent occurrence of pollution by oil slicks and water-soluble pollutants in recent years. The semiconductor photocatalysis is applied to sewage treatment owing to the advantages of energy-conserving and environmental protection. However, its application is limited by the defects of not solving oil slicks and the hard recyclability. In this paper, the high specific surface area and rod-shaped CdS were prepared using template and alkali-treated methods. Next, the alkylated SiO2 and alkali-treated CdS were deposited on pure fabric by physical deposition to prepare the multifunctional superhydrophobic fabric. The specific surface area and morphology of alkali-treated CdS were tested by BET specific surface area test and field emission scanning electron microscope. Besides, oil/water separation, water contact angle, and stability test experiments were performed to determine the superhydrophobic performance. Photocatalysis degradation efficiency and cycle degradation stability of multifunctional fabric were characterized by photocatalysis degradation Rh B experiment. Consequently, the alkali-treated CdS displays a high specific surface up to 343 m2 g−1. The multifunctional fabric presents excellent superhydrophobic performance with the water contact angle up to 155°. Meanwhile, the water contact angle of multifunctional fabric is always over 150° under various circumstances (acid-base corrosion, soaking time at 100 °C and frictional numbers), indicating that the multifunctional fabric has excellent superhydrophobic stability. Moreover, the fabric also exhibits outstanding photocatalysis performance (the degradation efficiency is 94% after 3 cycles). Our work provides a feasible method for addressing oil slicks on water surface and degrading water-soluble pollutants with extensive application prospects in water resource remediation. [ABSTRACT FROM AUTHOR]

To deal with the invalidation of commonly employed series model and parallel model in capacitance–voltage (C–V) characterization of organic thin films when current injection is significant, a three-element equivalent circuit model is proposed. On this basis, the expression of real capacitance in consideration of current injection is theoretically derived by small-signal analysis method. The validity of the proposed equivalent circuit and theoretical expression are verified by a simulating circuit consisting of a capacitor, a diode, and a resistor. Moreover, the accurate C–V characteristic of an organic thin film device is obtained via theoretical correction of the experimental measuring result, and the real capacitance is 35.7% higher than the directly measured capacitance at 5-V bias in the parallel mode. This work strongly demonstrates the necessity to consider current injection in C–V measurement and provides a strategy for accurate C–V characterization experimentally. [ABSTRACT FROM AUTHOR]

The design of highly efficient and stable electrocatalysts for oxygen reduction reaction (ORR) is still a great challenge. Herein, we prepared Co,N-codoped carbon nanocomposites (Co@NC-ZM) with entangled carbon nanotubes. The large Brunauer–Emmett–Teller surface area (604.7 m2 g−1), rich mesoporous feature, Co,N doping and synergetic effect between various species of Co@NC-ZM can expose more active sites and facilitate conductivity and mass transport. Benefiting from the above unique advantages, Co@NC-ZM exhibits excellent ORR performance with more positive onset potential (0.96 V) and half-wave potential (0.83 V) than those of commercial Pt/C (0.96 and 0.81 V, correspondingly). This work provides a new strategy for further exploring efficient non-precious-metal-based catalysts for ORR. [ABSTRACT FROM AUTHOR]

The epoch of reionization (EoR) marks the end of the Cosmic Dawn and the beginning of large-scale structure formation in the universe. The impulsive ionization fronts (I-fronts) heat and ionize the gas within the reionization bubbles in the intergalactic medium (IGM). The temperature during this process is a key yet uncertain ingredient in current models. Typically, reionization simulations assume that all baryonic species are in instantaneous thermal equilibrium with each other during the passage of an I-front. Here we present a new model of the temperature evolution for the ionization front by studying nonequilibrium effects. In particular, we include the energy transfer between major baryon species (e−, H i , H ii , He i , and He ii) and investigate their impacts on the post-ionization front temperature Tre. For a better step-size control when solving the stiff equations, we implement an implicit method and construct an energy transfer rate matrix. We find that the assumption of equilibration is valid for a nonrelativistic ionization front (speed less than), but deviations from equilibrium occur for faster fronts. The post-front temperature Tre is lower by up to 19.7% (at s−1) or 30.8% (at 1010 cm s−1) relative to the equilibrium case. [ABSTRACT FROM AUTHOR]

Owing to their large specific areas, high thermal stability and chemical inertness, two-dimensional boron carbon nitride nanosheets (BCNNs) have captured much attention in recent years in the field of adsorption of pollutants. The formation of BCNNs via incorporating carbon into boron nitride (BN) can effectively improve the photoelectric and adsorption properties of the latter. In this work, carbon-doped BN (BCN) nanosheets were prepared at 1100 °C via a molten salt route using boric acid, melamine and glucose as the main starting materials. The effects of molten salt type and carbon doping level on the formation of BCN were investigated, and their isothermal adsorption properties in a methylene blue (MB) aqueous solution were evaluated based on the Langmuir and Freundlich models. The results indicated that using molten LiCl-KCl as a liquid medium was more favorable than NaCl-KCl to the formation of BCNNs. As-prepared BC0.4N sample possessed a sheet-like structure of about 10 nm thick and a specific surface area as high as 484 m2 g−1. Moreover, the adsorption test of MB demonstrated a high adsorption capacity of 249.04 mg g−1, which was about 14 times higher than that in the case of the pristine BN, and the kinetic rate constant value in the case of using BC0.4N is about ten times as high as that of BN following a pseudo-second-order model, suggesting that the as-formed BC0.4N nanosheets could be potentially used as a value-added effective adsorbent for future wastewater remediation. [ABSTRACT FROM AUTHOR]

We present an experimental technique that can accurately measure the high-order photon correlations of various light fields based on double Hanbury Brown–Twiss scheme. The system consists of four conventional binary response single-photon counting modules which are non-photon-number-resolving detectors. We theoretically analyze the effects of the experimental conditions on the high-order photon correlations of coherent, chaotic thermal, Fock and squeezed vacuum states with considering the overall efficiency and background noise. In experiment, we determine the proper resolution time from 29 = 512 ns to 211 = 2048 ns and counting rate from 10 kc s−1 to 100 kc s−1 for characterizing the exact second-, third- and fourth-order photon correlations of chaotic thermal state. At complete time delays, we also observe the third- and fourth-order photon correlations of chaotic thermal state, with the maximum high-order correlation values of 5.99 ± 0.02 and 23.9 ± 0.2 respectively, which are in good agreement with the theoretical values of 6 and 24. The demonstrated experimental technique with high accuracy is a promising tool for investigating quantum optical coherence and ghost imaging. [ABSTRACT FROM AUTHOR]

The dissolution of transition metal (TM) cations from oxide cathodes and the subsequent migration and deposition on the anode lead to the deconstruction of cathode materials and uncontrollable growth of solid electrode interphase (SEI). The above issues have been considered as main causes for the performance degradation of lithium-ion batteries (LIBs). In this work, we reported that the solid oxide electrolyte Li1.5Al0.5Ti1.5(PO4)3 (LATP) coating on polyethylene (PE) polymer separator can largely block the TM dissolution and deposition in LIBs. Scanning electron microscopy (SEM), second ion mass spectroscopy (SIMS), and Raman spectroscopy characterizations reveal that the granular surface of the LATP coating layer is converted to a dense morphology due to the reduction of LATP at discharge process. The as-formed dense surface layer can effectively hinder the TM deposition on the anode electrode and inhibit the TM dissolution from the cathode electrode. As a result, both the LiCoO2/SiO-graphite and LiMn2O4/SiO-graphite cells using LATP coated PE separator show substantially enhanced cycle performances compared with those cells with Al2O3 coated PE separator. [ABSTRACT FROM AUTHOR]

Reconciliation is a necessary step in postprocessing of continuous-variable quantum key distribution (CV-QKD) system. We use globally coupled low-density parity-check (GC-LDPC) codes in reconciliation to extract a precise secret key from the raw keys over the authenticated classical public channel between two users. GC-LDPC codes have excellent performance over both the additive Gaussian white noise and binary-erasure channels. The reconciliation based on GC-LDPC codes can improve the reconciliation efficiency to 95.42% and reduce the frame error rate to 3.25 × 10–3. Using distillation, the decoding speed can achieve 23.8 Mbits/s and decrease the cost of memory. Given decoding speed and low memory usage, this makes the proposed reconciliation method viable approach for high-speed CV-QKD system. [ABSTRACT FROM AUTHOR]

We have demonstrated a novel method to enhance TiO2 photocatalysis by adopting a new ultrathin tetrahedral-amorphous-carbon (ta-C) film coating on Ag nanoparticles to create strong plasmonic near-field enhancement. The result shows that the decomposition rate of methylene blue on the Ag/10 Å ta-C/TiO2 composite photocatalyst is ten times faster than that on a TiO2 photocatalyst and three times faster than that on a Ag/TiO2 photocatalyst. This can be ascribed to the simultaneous realization of two competitive processes: one that excites the surface plasmons (SPs) of the ta-C-film/Ag-nanoparticle hybrid and provides a higher electric field near the ta-C/TiO2 interface compared to Ag nanoparticles alone, while the other takes advantage of the dense diamond-like ta-C layer to help reduce the transfer of photogenerated electrons from the conduction band of TiO2 to the metallic surface, since any electron transfer will suppress the excitation of SP modes in the metal nanoparticles. [ABSTRACT FROM AUTHOR]

The characteristics of the emission spectra of coaxial KrBr* excilamps driven by sinusoidal, rectangular and pulsed electronic control gear (ECGs) are investigated, based on the dielectric barrier discharge (DBD) with an annular gap of 10.5 mm. The radiant power of intense narrow band ultraviolet radiation at 207 nm is derived from the irradiance according to the Keitz formula, while the input power is computed from the integral of the product of voltage and current. The radiant characteristics of the 207 nm spectral line have been studied with regard to total pressure and bromine percentage, demonstrating an optimum pressure at 300–350 mbar as well as an optimum bromine percentage 0.1–0.3%, resulting in (3–4%) ± (0.3–0.5%) radiant efficiency at the optimum lamp power density of 360–540 W m−1. Of the three ECGs, results indicate that the pulsed waveform produces a higher efficiency than rectangular and sinusoidal waveforms. [ABSTRACT FROM AUTHOR]

Here we present a systematic study of the effects of pressure on the superconducting and spin/charge density wave (SDW/CDW) transitions of Ba1−xNaxTi2Sb2O (x = 0, 0.10, and 0.15) by means of resistivity measurements. For x = 0 and 0.10, external pressure results in a decease of the SDW/CDW transition temperature Tc; however, no measurable change is observed for the x = 0.15. The pressure effect on the superconducting transition temperature is different for all three samples. For BaTi2Sb2O (x = 0), Tc increases significantly from 1.2 K at zero pressure to ∼2.9 K at 16.1 kbar. The 10% Na-doped sample shows an initial Tc increase up to 4.2 K with pressure which saturates at higher pressure values. For higher Na concentrations (x = 0.15), Tc continuously decreases with increasing pressure. [ABSTRACT FROM AUTHOR]

We investigate the stability of helical superfluid phase in a spin–orbit coupled Fermi gas loaded in a bilayer optical lattice. The phase diagram of the system is constructed in the mean-field framework. We investigate the topological properties of the superfluid phases by a nontrivial application of the Fermi surface topological invariant to our time-reversal invariant system with degeneracies on the Fermi surface. We find that there is a first-order phase boundary in the phase diagram of half-filling case and the superfluid phases are all topological trivial. The superfluid phase is topological nontrivial when the filling fraction deviates from the half-filling. In the topological nontrivial superfluid phase, a full pairing gap exists in the bulk and gapless helical Majorana edge states exist at the boundary. [ABSTRACT FROM AUTHOR]

A transparent cosputtered ITO–ZnO film was used as an ohmic contact electrode to the n-type ZnO layer. The contact resistance of the ITO–ZnO/n-ZnO contact system was optimized by a rapid thermal annealing (RTA) treatment. Through x-ray diffraction and Auger electron spectroscopy depth profile measurements, the achievement on the ohmic contact of the ITO–ZnO/n-ZnO contact system was attributed to the outdiffusion of the oxygen atoms at the n-type ZnO layer surface, which was favourable for the increase of the electron carriers. By contrast, the mechanism responsible for the degradation of the contact resistance was due to the significant outdiffusion of the zinc atoms at the n-type ZnO layer surface, which also resulted in the marked peak shift of the Zn2In2O5 phase. The resulting n-ZnO/p-GaN heterojunction light-emitting diode fabrication, which used the transparent ITO–ZnO/n-ZnO ohmic contact system, exhibited rectifying behaviour and emitted a near-ultraviolet radiation at approximately 410 nm. [ABSTRACT FROM AUTHOR]