In this study, high-voltage pulses are used to drive dielectric barrier discharge plasma actuators (DBDAs) for flow control purposes. The rising/falling edges of the pulse are kept nearly constant in nanosecond timescale, while the pulse width is varied from nanosecond to microsecond timescale. The impact of pulse width on the characteristics of the DBDA is investigated experimentally with a high-speed

We have fabricated and investigated CTSe:Ge bi-layer devices by modulus spectroscopy combined with impedance spectroscopy to understand the electrical properties of hetero- and back-contact junctions. The equivalent circuit model is developed to decouple the properties of each junction at different frequency ranges. Modeling and numerical simulations with the in-house MATLAB modeling suites connected

Plasma decay was experimentally studied in the afterglow of a repetitively pulsed nanosecond discharge in a stoichiometric H2:O2 mixture. An additional bias DC electric field was applied to heat electrons during the discharge afterglow between the high-voltage pulses. The energy input per pulse was so small that the changes in both chemical composition and gas temperature were negligible. Using the

In this paper, a new kind of spoof surface plasmon polariton (SSPP) beam splitter integrated with band-rejection filtering functions is presented. Firstly, the mechanism of single-band rejection phenomena of the SSPP transmission lines (TLs) with and without T-shaped decorations are revealed through dispersion analyses. Based on the single-band rejection filter, multi-band rejection filters are further

Recently, all-inorganic cesium lead bromide (CsPbBr3) perovskite has attracted tremendous interest due to its promise for green light photonic and optoelectronic devices. The growth of high-quality planar micro-/nano-structures of CsPbBr3 on the technologically important silicon substrate is an important issue for these applications, which has not yet been well explored. Herein we fabricate millimeter-scale

Durability tests of thermal protection system (TPS) materials for space vehicles is of paramount importance in developing TPS materials. The limits of the presently used techniques and the need for higher accuracy and precision demand new reliable and more sensitive measurement methods. In this paper we present the validation of a new on-line and non intrusive technique to estimate the TPS material

Time-of-flight (ToF) neutron imaging offers complementary attenuation contrast to x-ray computed tomography, coupled with the ability to extract additional information from the variation in attenuation as a function of neutron energy (ToF) at every point (voxel) in the image. In particular, Bragg edge positions provide crystallographic information and therefore enable the identification of crystalline

The existence of a recast layer of film cooling holes on turbine blades imposes a crucial problem that affects the quality of fast electrical discharge machining (EDM) drilling. This paper focuses on an evolution process from molten material generation to recast layer formation. Single pulse discharge observation experiments with a high speed camera and a self-built observation platform were carried

The enhancement of the electric field in a hollow metallic cylinder is optimized as a function of the angular frequency of incident light. A resonant enhancement occurs by exciting azimuthal surface plasmon (SP) and the enhancement is uniform inside the cylinder which is useful for spectroscopy. The enhancement of the electric field is numerically calculated by solving the Helmholtz equation as a function

Plasma technology has emerged as an efficient, simple, and eco-friendly method for activating seed germination processes. Most studies on this subject have focused on the morphological and wetting effects on the surface state of seeds and attributed the improvement in germination occasionally found to the induced hydrophilicity and a higher water imbibition rate. Recently, the involvement of reactive

A dual-polarized photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) was proposed for measuring the refractive indexes (RIs) of liquids. A gold film and a liquid analyte were successively wrapped around the outer surface of the PCF to stimulate the external SPR effect, which greatly reduced the manufacturing difficulties, compared to depositing the gold film and filling the

Patterning a wide range of colloidal plasmonic nanoparticles into prescribed spatial arrangements, analogous to the formation of natural materials, enables the fabrication of functionalized structures with novel optical properties, such as Fano resonance, magneto-optical Kerr effect, negative refraction, etc. Currently, capillarity-assisted particle assembly is always utilized to place colloidal particles

Complex viscoelastic materials exhibit power law (PL) relaxations, as opposed to simple materials described by exponential decays. Other interesting materials, like living cells, hold a universal double PL behavior whose exponents depend on the health and type of the cells. Usually, only dynamic assays are considered capable to study such viscoelastic relaxation mechanisms. In this work, we propose

We compute the thermal conductivity, κ, of five representative III–V ternary alloys—namely In x Ga1 − x As, GaAs1 − x P x , InAs1 − x Sb x , GaAs1 − x N x , and GaP1 − x N x —in the whole range of compositions, and in zincblende and wurtzite crystal phases, using a first-principles approach and solving the phonon Boltzmann transport equation beyond the relaxation time approximation. We discuss the

Acoustic metamaterials possess fire-new capacities to manipulate the reflected, refracted and diffracted wave wavefronts effectively and flexibly through designing special artificial structures. In this paper, a transmission-type phase gradient metamaterials with high efficiency transmission and variations phase shift covering a full range of 2π was reported. Capacities of manipulating transmission

An integrated device of GaN-based micro-LED and detector was developed for multifunctional applications in visible light communication (VLC). The size of the current spreading layer was used to define the micro-LED size for high-bandwidth transmitter. The device can also be used as high-sensitivity photodetector (PD). In this scenario, the light receiving area is not restricted by the size of the current

Studies of the deep energy levels and nonradiative carrier capture induced by sulfur doping in silicon were initiated 60 years ago; however, the defect configurations, their deep energy levels, and the carrier capture cross sections are still not well understood. In this study, we focus on SSi substitution, and perform a first-principles study of its defect configurations and the deep energy levels

An ultra wide-angle and broad-band magneto-electric dipole like metamaterial absorber (MEDMA) was proposed. The trapezoidal resistance films on the top layer and the upright resistance films in the middle are both equivalent to electric dipoles. The metal back plate together with the resistance films on the top layer are equivalent to magnetic dipoles. The radiation characteristics of magnetic dipole

The light extraction efficiency (LEE), external quantum efficiency (EQE), and current–voltage characteristics of deep ultraviolet light emitting diodes (DUV-LEDs) with different aluminum mole fractions in the p-AlGaN layers have been investigated. Optimizing the p-AlGaN layer composition requires a tradeoff between reducing the absorption losses and limiting the increases in the p-contact resistance

A novel quad-polarization reconfigurable holographic artificial impedance surface that exploits the tunable dielectric permittivity of nematic liquid crystal is proposed. The arc-shaped strip is introduced and serves as the fundamental element, and further combined with holographic modulation, electromagnetic radiation at the terahertz band is realized. By partitioning the circular surface into several

Dielectric barrier discharge (DBD) plasma technology is a promising method for producing methanol from CO2 hydrogenation as the reaction can be run at atmospheric pressure and temperatures below 100 C. The choice of the catalyst is crucial and has to be made not only according to its activity and selectivity towards the desired product, but its effect on plasma properties. In this work, the influence

We investigate changes in optical coherence tomography (OCT) images in response to evoked neural activity in the sciatic nerve of rats in vitro. M-scans were obtained on peripheral nerves of rats using a swept source polarisation sensitive OCT system, while a nerve cuff acquired electrical neural recordings. From a total of 10 subjects: three had no stimulation (controls), three had paw stimulation

Mixed cation perovskite solar cells (PSCs) have shown high stability over 1000 h under outdoor conditions. In this paper, we simulated fluorine-doped tin oxide/TiO2/(FAPbI3)0.85(MAPbBr3)0.15/ Spiro-OMeTAD solar cell as the base structure by SCAPS-1D software. We then studied the effects of E V position of hole transport layer (HTL) and E C position of electron transport layer (ETL) and carrier density

In this study, we synthesized gold spheroidized particles with sub-micrometer diameters via atmospheric-pressure plasma-assisted processing with inkjet droplets. Microdroplets of chloroauric acid (HAuCl4) solution were generated by an inkjet device with high reproducibility and exposed to radio frequency plasma. The synthesized sub-micrometer gold particles have a very narrow size distribution (3%–9%

Catalytic materials play important roles in chemical, energy, and environmental fields. The exhaustion of fossil fuels and the resulting deteriorative environment have become worldwide problems to be solved urgently. Therefore, treatment of catalytic materials by a green process is required for a sustainable future, and the atom efficiency of the catalytic materials should be improved at the same time

The thermodynamic stability of germanium tin alloys is investigated across the composition range by applying density functional theory together with the cluster expansion formalism (CE). It is known that GeSn alloys are immiscible and that non-equilibrium growth techniques are required to produce metastable films and nanostructures. Insight into the driving forces behind component segregation is gained

An inhomogeneity into a conductive matrix deforms the flow pattern of an applied electric current. A usual current cloak can be defined as a permanent modification of the matrix properties around the inhomogeneity guaranteeing that the current flow pattern is similar before and after passing by the modified zone, so it implies the ‘electrical invisibility’ of the inhomogeneous region. Here we introduce

In recent years, the thermal and chemical non-equilibrium properties of arc plasmas have been among the most critical topics in the modeling of welding arcs. Non-equilibrium phenomena can be observed in the near-electrode regions, where the characteristics of the arc are determined. Although non-equilibrium modeling should contribute to a deeper understanding of the gas–metal arc-welding (GMAW) process

This study is to investigate the role of O3 on NO and NO2 oxidations to selective formations of NO2 − and NO3 − in plasma-treated water. Two plasma reactors, a surface dielectric-barrier discharge (DBD) and a coaxial DBD jet, are employed to water treatment with a working gas primarily consisting of N2 and O2. Results of surface DBD show that O3 first is increased with plasma treatment time, reaching

Ultrafast carrier response of perovskite/MoO3/graphene heterostructure was investigated by optical-pump terahertz (THz) probe spectroscopy. The high work function of MoO3 changes the tunable graphene Fermi level via hole doping. Compared with monolayer graphene, it generates a more negative photoconductivity and enables ultra-fast THz functional manipulation. The subsequent THz signal decrease is related

In the presence of the Hubbard interaction, graphene zigzag nanoribbons have spontaneous edge magnetism with anti-parallel configuration, whose amplitude can be tuned by a transversal electric field. As the electric field increases or decreases across a critical value, the edges are demagnetized or re-magnetized, respectively. A magnetic field at each edge determines the orientation of the re-magnetization

We have investigated the spin pumping phenomenon in Fe80Co20/Ta bilayers of different thicknesses in which the ferromagnet grows epitaxially on MgO substrates. We have obtained a Gilbert damping constant for Fe80Co20 as low as α = 1.3(1) 10−3, which is smaller than values generally reported in metallic ferromagnets. From the dependence of α with the Fe80Co20 thickness, we extracted the value of the

We investigate the magnetic coupling across the antiferromagnetic–antiferromagnetic (AFM–AFM) interface for the prototypical CoO-NiO bilayer system where the bulk Nel temperature (T N ) of NiO is higher than that of CoO. Using the temperature-dependent exchange-scattered electron intensities from the surface AFM lattice, the surface T N of CoO was estimated as a function of the CoO/NiO film thicknesses

Various formulations of Co, Ni and K modified MoS2-based catalysts were synthesized hydrothermally and compared in their catalytic performance in CO2 hydrogenation at 21 bar and 220 C–330 C. The products were CO, CH4 and methanol. The addition of K reduced the selectivity to CH4 and moved the maximum of the methanol formation rate to a higher temperature. The materials were characterized by N2 physisorption

Pd takes various chemical forms according to the types of catalysts and even its pristine chemical state is often subject to change in operation. To understand the mechanism how Pd-based catalysts activate reactions, it is important to have a capability to identify the surface chemical state of Pd-based catalysts in contact with reactants. In this study, we conducted in situ near ambient pressure-x-ray

Understanding how the brain functions is one of the grand challenges in modern scientific research. Similar to a computer, a functional brain is composed of hardware and software. The major bottleneck lies in the difficulty to directly observe the brain ‘software’, i.e. the rule and operating information used by the brain that might emerge from pan-neuron/synapse connectome. A recognized strategy for

First Townsend ionization coefficient α in gas mixture of He with N2 is relevant for modeling of the development and chemical activity of atmospheric pressure plasma jets. This study determined α from measurements of current versus electrode separation in a steady-state non-self-sustaining Townsend discharge set-up. The measurements were carried out in absolute pressure range of 10–800 Torr and reduced

The electron dynamics in a stable and non-filamentary Argon plasma jet, generated using AC excitation at kHz frequencies and interacting with a liquid surface either at floating potential or electrically grounded were examined using laser Thomson scattering. In the case of a floating liquid, two discharge events were observed during each half-cycle of the applied sinusoidal voltage. In the grounded

We theoretically investigate the microwave third-harmonic generation (THG) produced by free carriers in the conduction band of electrostatically doped phosphorene. It is assumed that a plane polarized microwave of frequency ω is incident normally on the phosphorene layer deposited on a dielectric substrate. Using an extremely simple model for the phosphorene’s anisotropic electronic structure, we calculate

The unusually high lattice thermal conductivity of semiconducting cubic boron arsenide (BAs) has motivated studies of the bulk electronic band structure of BAs for its potential use as an active layer material in electronic devices. However, the surface electronic structure of BAs remains to be investigated. Scanning tunneling spectroscopy (STS) is employed here to probe the electronic structure of

Antimony (Sb) and its oxides, as promising electrode materials, have attracted much attention because of their low cost, environmental friendliness, and high theoretical capacity. Herein, boron doped flower-cluster-like Sb/SbO2@reduced graphene oxide (rGO) composites are synthesized for use as sodium-ion battery anode materials using a solvothermal strategy. The contents of Sb and antimony oxide (SbO2)

We theoretically, numerically and experimentally report the localization of an acoustic wave at the interface between two one-dimensional hyperuniform materials of different geometrical representations. These materials suppress the acoustic scattering in the long wavelength regime, being rather disordered and degenerate, while possessing a wide band gap. In this work, these hyperuniform materials are

In this study, the effect of the burst ratio (BR) on flow separation control using an alternating-current dielectric barrier discharge plasma actuator (DBDPA) was investigated. The effects of BR on the lift force on the NACA0015 airfoil were quantitatively evaluated by force measurements, and those on the flow field were measured by particle image velocimetry (PIV) and Schlieren visualisation. The

In this paper, we demonstrate a new heterojunction ultraviolet (UV) photodetector in a superstrate configuration, i.e. glass/FTO/ZnO NRs/rGO/Au, constructed via the dip-coated method to form reduced graphene oxide (rGO) layer on the surface of ZnO nanorod arrays (NRs). The rGO compensates for surface oxygen vacancies by the oxygen-containing groups and improves the crystal properties of ZnO NRs after

High-performance anisotropic bonded magnets need a high volumetric filling fraction of magnetic powder in a polymer binder and good alignment while possessing adequate mechanical properties. The correlation between the degree of alignment (DOA) and the volumetric filling fraction of magnetic powder, the type of binder and the processing parameters have been studied using Nd–Fe–B anisotropic bonded

Photovoltaic (PV) cell technology has made great progress over the past few decades, bringing the PV energy cost down to a point where it is competitive to conventional electricity prices. While monofacial panels have historically dominated the market, recent developments in the manufacturing of bifacial panels (collecting light from both faces) have made them accessible for commercial applications

In this study, a two-dimensional simulation of atmospheric-pressure streamer discharge with a dielectric on the cathode was conducted to investigate the effects of relative permittivity on primary and secondary streamer characteristics. An electrode configuration with an air gap of 0.1 mm was employed. The input parameters of the simulations were the relative permittivity, dielectric thickness, and

From the viewpoint of interface quality within the gate stack, it is crucial to accurately evaluate the device performance of ferroelectric field-effect transistors (FeFETs). In this article, a measurement scheme composed of pulse configurations is designed to avoid dynamic changes in the threshold voltage of the FeFET during charge pumping (CP) measurements. Three types of control devices experiencing

Low-operating-voltage (<2 V) organic thin-film transistors (OTFTs) and P-channel metal-oxide-semiconductor (PMOS) inverter circuits are fabricated on a 125 m-thick flexible polyethylene naphthalate substrate using a blend of 2,7-dihexyl-dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene and polystyrene as an active p-type organic semiconducting material. All three electrodes (gate, source, and

The understanding of the ro-vibrational dynamics in molecular (near)-atmospheric pressure plasmas is essential to investigate the influence of vibrational excited molecules on the discharge properties. In a companion paper Kuhfeld et al (2021 J. Phys. D: Appl. Phys. 54 305204), results of ro-vibrational coherent anti-Stokes Raman scattering (CARS) measurements for a nanosecond pulsed plasma jet consisting

The non-equilibrium ro-vibrational distribution functions of molecules in a plasma can heavily influence the discharge operation and the plasma-chemistry. A convenient method for measuring the distribution function is coherent anti-Stokes Raman scattering (CARS). CARS spectra are measured in a ns-pulsed plasma between two parallel, 1 mm spaced molybdenum electrodes in nitrogen at 200 mbar with pulse

This study compares the impact of different plasma environments on the damage formation dynamics of polycrystalline monolayer graphene films on SiO2/Si substrates and investigates the combined effects often observed in low-pressure argon plasmas. After careful characterization of the discharge properties by Langmuir probes and optical absorption spectroscopy, three operating conditions were selected

Solution-processed organic/inorganic hybrid halide perovskites are a class of very promising photovoltaic materials because of their extraordinary optoelectronic properties. However, numerous intrinsic defects within perovskite films limit the performance enhancement of perovskite solar cells (PSCs). Herein, we introduce three different alkali metal fluoride additives into the perovskite precursor

The non-Arrhenius behaviour of Ge2Sb2Te5 conductivity is attributed to the non-linear temperature dependence of the Fermi level, assuming extended state conduction by free holes. The temperature-dependent Fermi level is shown to alter values of activation energy and prefactor for conductivity so that their exact determination becomes impossible using the conductivity data alone. However, if one assumes

In this study, microstructural variation of hydroxyapatite (HAp) ceramics upon thermal treatment in air at different temperatures was investigated by x-ray diffraction patterns, Raman and x-ray photoelectron spectroscopies. The results revealed a significant dependence of the microstructure of nonstoichiometric HAp on temperature, because of the competition between hydroxylation and different kinds

The van der Waals bonded transition metal phosphorous trichalcogenides FePS3, NiPS3 and MnPS3 have recently attracted renewed attention due to the possibility of exfoliating them into their monolayers. Although the three compounds have similar electronic structure, the magnetic structure differs due to subtle differences in exchange and magnetic anisotropy and the materials thus comprise a unique playground

Photocatalysts are expected to contribute to the sustainable development of human society due to their ability of converting solar energy to chemical fuel and removing environmental contamination. In principle, photocatalytic efficiency is intimately related to the availability of sunlight, and thus it is vital to extend the light absorption range to the low-energy near-infrared (NIR) region. A great

The contact area between solid insulations, namely solid–solid interfaces, affect the dielectric characteristics of an entire insulation system. With the theoretical and experimental studies covered in this paper, we intend to investigate the effects of the elastic modulus, interface contact pressure, and surface smoothness/roughness on the tangential alternating current (AC) breakdown strength of

The correlation between the optimal performance of indoor photovoltaics (IPVs) and spectral characteristics of white light-emitting diode (LED) sources has been investigated theoretically. We calculated the Schockley–Queisser limit of IPVs under multi-color white LEDs with different correlated color temperature (CCT), color rendering index (CRI) and luminous efficacy of radiation (LER). It is found

The elimination of vinasse contaminant generated by the tequila industry and other alcoholic beverages is of current interest because millions of liters are produced every year and it cannot be released in the environment due to its low pH and high content of organic material. As an effort to reuse/recycle such a contaminant, we report the use of a mixture of vinasse-contaminant + H3PO4 as the electrolyte