Fraction Of Ions Research Articles

Formation of robust CEI film on high voltage LiNi0.6Co0.2Mn0.2O2 cathode enabled by functional [PIVM][TFSA] ionic liquid additive

• A novel multifunctional ionic liquid was designed and synthesized using a two-step method. • Physicochemical properties of the new ionic liquid with DMC and EMC were investigated. • The cycle performance and rate properties were enhanced by adding an ionic liquid additive. • The mechanisms were determined by CV, SEM and XPS analysis techniques. The ionic liquid 1-(3-amino-3-oxopropyl)-3-vinylimidazolium bis(trifluoromethylsulfonyl)amide ([PIVM][TFSA]) was synthesized and applied in the electrolyte of Li/LiNi 0.6 Co 0.2 Mn 0.2 O 2 lithium ion batteries. The thermostability of this pure ionic liquid was investigated to provide a wide liquid range from -50 ℃ to 200 ℃. The physicochemical properties of binary mixtures of this ionic liquid with DMC and EMC were measured at different temperatures and with different ionic liquid mole fractions. [PIVM][TFSA] widens the electrochemical window of the electrolyte. The ionic liquid inhibits the increasing of water and HF content in the electrolyte. A comparison of charge and discharge performances in different electrolytes with various content of ionic liquid is reported. The electrolyte with the concentration of 1.0 wt % [PIVM][TFSA] has the best electrochemical properties. It enhances the initial capacity, the capacity retention and the high current rate performance of the cells. The surface film on the electrodes was confirmed by SEM and XPS that the ionic liquid [PIVM][TFSA] participated in membrane formation and played an active role.

Chromospheric extension of the MURaM code

Context. Detailed numerical models of the chromosphere and corona are required to understand the heating of the solar atmosphere. An accurate treatment of the solar chromosphere is complicated by the effects arising from non-local thermodynamic equilibrium (NLTE) radiative transfer. A small number of strong, highly scattering lines dominate the cooling and heating in the chromosphere. Additionally, the recombination times of ionised hydrogen are longer than the dynamical timescales, requiring a non-equilibrium (NE) treatment of hydrogen ionisation. Aims. We describe a set of necessary additions to the MURaM code that allow it to handle some of the important NLTE effects. We investigate the impact on solar chromosphere models caused by NLTE and NE effects in radiation magnetohydrodynamic simulations of the solar atmosphere. Methods. The MURaM code was extended to include the physical process required for an accurate simulation of the solar chromosphere, as implemented in the Bifrost code. This includes a time-dependent treatment of hydrogen ionisation, a scattering multi-group radiation transfer scheme, and approximations for NLTE radiative cooling. Results. The inclusion of NE and NLTE physics has a large impact on the structure of the chromosphere; the NE treatment of hydrogen ionisation leads to a higher ionisation fraction and enhanced populations in the first excited state throughout cold inter-shock regions of the chromosphere. Additionally, this prevents hydrogen ionisation from buffering energy fluctuations, leading to hotter shocks and cooler inter-shock regions. The hydrogen populations in the ground and first excited state are enhanced by 102–103 in the upper chromosphere and by up to 109 near the transition region. Conclusions. Including the necessary NLTE physics leads to significant differences in chromospheric structure and dynamics. The thermodynamics and hydrogen populations calculated using the extended version of the MURaM code are consistent with previous non-equilibrium simulations. The electron number and temperature calculated using the non-equilibrium treatment of the chromosphere are required to accurately synthesise chromospheric spectral lines.

Structural evolution and microwave dielectric properties of CaTiO3–La(Mg2/3Nb1/3)O3 ceramics

Abstract(1 − x)CaTiO3–xLa(Mg2/3Nb1/3)O3 (CT–LMN; x = 0–1.0) solid solutions were prepared by a solid‐state reaction method. A phase transition from a disordered orthorhombic (Pbnm) structure to a 1:1 ordered monoclinic (P21/n) structure was observed when x increased from 0.5 to 0.6. Some new parameters, such as ionic polarizability in a polyhedron and ionic packing fraction in a polyhedron, were defined to explain the structure–property relationships of CT–LMN ceramics based on the Rietveld refinement results. The measured dielectric constant (εr‐mea) decreased monotonically with B‐site ionic polarizability in the [BO6] octahedron () when the x value increased from 0 to 1.0. The quality factor (Qf) was dominated by the packing fraction of B‐site cations in the [BO6] octahedron (PF[B]), and both presented an increasing trend. The temperature coefficient of resonant frequency (τf) decreased from +588.5 to −79.7 ppm/°C, and it was highly correlated to the tolerance factor (t), and PF[B]. The highest Qf value is obtained at x = 1.0 when sintered at 1600°C for 10 h with εr = 23.65 ± 0.2, Qf = 33517 ± 2000 GHz (@7.8 GHz), and τf = −79.7 ± 2.0 ppm/°C. Moreover, a near‐zero τf value was achieved at x = 0.4 with εr = 43.52 ± 0.2, Qf = 17239 ± 2000 GHz (@5.2 GHz), and τf = −10.2 ± 2.0 ppm/°C.

Investigating star-formation activity towards the southern H ii region RCW 42

ABSTRACT The star-forming activity in the H ii region RCW 42 is investigated using multiple wavebands, from near-infrared to radio wavelengths. Located at a distance of 5.8 kpc, this southern region has a bolometric luminosity of 1.8 × 106 L⊙. The ionized gas emission has been imaged at low radio frequencies of 610 and 1280 MHz using the Giant Metrewave Radio Telescope, India, and shows a large expanse of the H ii region, spanning 20 × 15 pc2. The average electron number density in the region is estimated to be ∼70 cm−3, which suggests an average ionization fraction of the cloud to be 11 % . An extended green object EGO G274.0649-01.1460 and several young stellar objects have been identified in the region using data from the 2MASS and Spitzer surveys. The dust emission from the associated molecular cloud is probed using Herschel Space Telescope, which reveals the presence of five clumps, C1-C5, in this region. Two millimetre emission cores of masses 380 and 390 M⊙ towards the radio emission peak have been identified towards C1 from the ALMA map at 1.4 mm. The clumps are investigated for their evolutionary stages based on association with various star-formation tracers, and we find that all the clumps are in active/evolved stage.

Characterization of beam ion loss in high poloidal beta regime on EAST

A critical issue for achieving the integrated operation of steady-state long-pulse high-confinement (H-mode) plasmas on experimental advanced superconducting tokamak (EAST) is to improve beam ion population confinement during neutral beam injection (NBI). To study the characterization of beam ion loss and improve beam ion confinement, the steady-state long pulse scenario discharges were conducted on EAST (β p ⩾ 2.0, β N ⩾ 1.7, q 95 ⩾ 6.7 and H 98y2 ⩾ 1.1) with NBI heating. Based on neutron yield, the beam voltage and line-averaged electron density were adjusted from 50 kV to 60 kV and 4.4 × 1019 m−3 to 5.0 × 1019 m−3, respectively. The results show that the dominant mechanisms of beam ion loss are shine-through loss, prompt loss, and stochastic ripple loss. The shine-through loss fraction is determined by initial velocity, flight time and entire beam path. The change in prompt loss fraction is caused by the change in the deposition of beam ions. The change in stochastic ripple loss fraction is caused by the change in the initial fraction of trapped-confined ions. Detailed physics shows that the prompt loss fraction during counter-Ip injections (∼45%) is far larger than during co-Ip injections (∼5%) due to the finite orbit width. The lost ions are mainly deposited on the lower divertor or below the midplane since the direction of magnetic drift is vertical down. The orbit types of prompt loss during counter-Ip injections are mainly trapped-lost and ctr-passing lost. To minimize the prompt loss fraction during counter-Ip injections, a reversed Ip configuration (rev-Ip) discharge #94758 was conducted. The result suggests that the beam ion wall load fraction during counter-Ip tangential injection (∼3%) is far lower than that in normal Ip configuration (nor-Ip) discharge #94820. It is also found that the confinement of beam ion population in the counter-Ip injection #94758 was greatly improved when compared to #94820. This study can provide unique support for the improvement of beam ion population confinement and for the performance evaluation of the NBI system on EAST and future tokamaks.

Galaxy cluster photons alter the ionization state of the nearby warm–hot intergalactic medium

ABSTRACT The physical properties of the faint and extremely tenuous plasma in the far outskirts of galaxy clusters, the circumgalactic media of normal galaxies, and filaments of the cosmic web remain one of the biggest unknowns in our story of large-scale structure evolution. Modelling the spectral features due to emission and absorption from this very diffuse plasma poses a challenge, as both collisional and photoionization processes must be accounted for. In this paper, we study the ionization by photons emitted by the intracluster medium in addition to the photoionization by the cosmic ultraviolet/X-ray background on gas in the vicinity of galaxy clusters. For near-massive clusters such as A2029, the ionization parameter can no longer describe the ionization balance uniquely. The ionization fractions (in particular of C iv, C v, C vi, N vii, O vi, O vii, O viii, Ne viii, Ne ix, and Fe xvii) obtained by taking into account the photoionization by the cosmic background are either an upper or lower limit to the ionization fraction calculated as a function of distance from the emission from the cluster. Using a toy model of a cosmic web filament, we predict how the cluster illumination changes the column densities for two different orientations of the line of sight. For lines of sight passing close to the cluster outskirts, O vi can be suppressed by a factor of up to 4.5, O vii by a factor of 2.2, C v by a factor of 3, and Ne viii can be boosted by a factor of 2, for low-density gas.

The role of sulfur valency on thermoelectric properties of sulfur ion implanted copper iodide

Copper iodide (CuI) is a promising semiconductor with many potential applications in the fields of opto-electronics, solar cells, photodetectors and thermoelectric for energy harvesting. 30 keV 32S+ ions were implanted with fluences between 5.0 × 1014 and 1.1 × 1016 ions cm−2 which results in 0.3–5.5 at% peak sulfur concentration at an average depth of ~ 30 nm. Sulfur implantation increased electrical conductivity by up to 100 % (42.3 Ω−1 cm−1) for film implanted with the highest fluence (1.1 × 1016 ions cm−2), which was due to an increase in hole density of one order of magnitude. The thermoelectric power factor increased by over 300 % for low-fluence (≤1.0 × 1015 ions cm−2) implanted CuI films which is attributed to a simultaneous 22 % increase in electrical conductivity (25.9 Ω−1 cm−1) and a 95 % increase in the Seebeck coefficient (498.6 µVK−1), which overcomes the typical trade-off. XPS results showed that doped sulfur ions are in S2- states for low-concentration doped films, whereas for high-fluence (≥ 2.5 × 1015 ions cm−2) implanted films, a fraction of the sulfur ions are also present in an elemental state. Sulfur solubility impacts its valency which alters the defect chemistry and thermoelectric properties of the sulfur implanted CuI films. Sulfur doping by ion implantation is a promising strategy to improve the electrical conductivity and power factor in wide bandgap thermoelectric materials.

Effects of gas pressure and bias potential on electron beam nitriding of titanium

We have studied the effects of gas pressure and bias potential on ion-plasma nitriding of titanium in an electron beam-produced plasma generated in the forevacuum pressure range. We present the results of scanning electron microscopy, x-ray analysis, and tribological studies of the modified layers of nitrided samples. The results of measurements are given, and the correlation between parameters (ion mass-to-charge composition, plasma density, electron temperature) of the beam-plasma and of the nitrided surface is found. Increased working gas pressure leads to an increase in the fraction of atomic nitrogen ions in the plasma, which results in increased surface layer hardness, depth of penetration of nitrogen atoms into the sample, and wear resistance. Higher absolute values of sample bias potential contribute to increased plasma density near the sample surface and a corresponding increase of hardness and wear resistance of the sample.

Rheological Characterization of Mixed Aqueous Solutions of Enzymatic Hydrolysis Lignin and Ionic Liquid

AbstractHere we present a rheological study of enzymatic hydrolysis lignin (EH lignin) in 1‐butyl‐3‐methylimidazolium chloride ([C4min]Cl) aqueous solutions. The effects of ionic liquid mass fraction, shear rate and temperature on the viscosity and macromolecular chain configuration of EH lignin / C4min] Cl aqueous solution were studied. The results showed that the viscosity of the aqueous solutions increased with the increase of lignin content. The mass percentages of overlapping and winding, responding to divisions of lignin macromolecules existence state, were varied with changing in the temperature and mass percentages of ionic liquid. Increasing the mass of ionic liquid will significantly change the viscosity of lignin solution. Most of the lignin solutions had shear thinning behavior, suggesting that macromolecular chains of lignin moved with orientation to the fluid, and disentangled under the shear force. The viscosity of lignin solution decreased with the increase of temperature, and the viscosity activation energy increased with the increase of lignin or ionic liquid mass fraction.

Influence of water of negative oxidation-reduction potential with hydrogen saturation on kidney function in rats

Objective. To study the effect of water load of negative redox potential with hydrogen saturation on renal function in comparison with induced diuresis with water of negative redox potential without hydrogen saturation.Material and methods. In experiments on 60 male white-nonlinear rats weighing 0.16-0.18 kg, the effect of loading with ordinary tap water (redox potential 90.4 ± 1.45 mV), water of negative redox potential without saturation with hydrogen (redox potential - 304.5 ± 4.79 mV) and water of negative redox potential with hydrogen saturation 1.0 - 1.2 ppm and redox potential -297.3 ± 5.27 mV. Used: experimental, physiological, biochemical, chemical, physicochemical, statistical research methods.Results. Under water load of negative redox potential with hydrogen saturation in comparison with induced diuresis of negative redox potential with the use of microhydrin, there was no inhibition of glomerular filtration, filtration fraction and proximal reabsorption of sodium ions, change restorative potential of urine. These changes are explained by the lack of activation of the dysregulatory mechanism of basal vascular tone of the renal cortex under conditions of water load of negative redox potential with hydrogen saturation.Conclusion. Water loading of negative redox potential with hydrogen saturation in comparison with induced diuresis of negative redox potential without hydrogen saturation causes recovery of glomerular filtration rate, filtration fraction and proximal reabsorption of sodium ions, due to the lack of activation of the mechanism of basal vascular tone of the renal cortical substance, due to the high permeability of molecular hydrogen and uniform delivery of electrons to all organs and tissues.

A Smart Molecule Showing Spin Crossover Responsive Aggregation-Induced Emission

A Smart Molecule Showing Spin Crossover Responsive Aggregation-Induced Emission

Damping of Alfvén Waves in MHD Turbulence and Implications for Cosmic Ray Streaming Instability and Galactic Winds

Alfvénic component of MHD turbulence damps Alfvénic waves. The consequences of this effect are important for many processes, from cosmic ray (CR) propagation to launching outflows and winds in galaxies and other magnetized systems. We discuss the differences in the damping of the streaming instability by turbulence and the damping of a plane parallel wave. The former takes place in the system of reference aligned with the local direction of magnetic field along which CRs stream. The latter is in the reference frame of the mean magnetic field and traditionally considered in plasma studies. We also compare the turbulent damping of streaming instability with ion-neutral collisional damping, which becomes the dominant damping effect at a sufficiently low ionization fraction. Numerical testing and astrophysical implications are also discussed.

Radio spectra of protostellar jets: Thermal and non-thermal emission

ABSTRACT Protostellar jets and outflows are pointers of star-formation and serve as important sources of momentum and energy transfer to the interstellar medium. Radio emission from ionized jets have been detected towards a number of protostellar objects. In few cases, negative spectral indices and polarized emission have also been observed suggesting the presence of synchrotron emission from relativistic electrons. In this work, we develop a numerical model that incorporates both thermal free–free and non-thermal synchrotron emission mechanisms in the jet geometry. The flux densities include contribution from an inner thermal jet, and a combination of emission from thermal and non-thermal distributions along the edges and extremities, where the jet interacts with the interstellar medium. We also include the effect of varying ionization fraction laterally across the jet. An investigation of radio emission and spectra along the jet shows the dependence of the emission process and optical depth along the line of sight. We explore the effect of various parameters on the turnover frequencies and the radio spectral indices (between 10 MHz and 300 GHz) associated with them.

An approximate recipe of chromospheric radiative losses for solar flares

Context. Radiative losses in the chromosphere are very important for the energy balance of the Sun. There have been efforts to make simple lookup tables for chromospheric radiative losses in the quiet Sun. During solar flares, the atmospheric conditions are quite different, and the currently available recipe is constructed from semi-empirical models. How these recipes work in flare conditions remains to be evaluated. Aims. We aim to construct an approximate recipe of chromospheric radiative losses for solar flares. Methods. We tabulate the optically thin radiative loss, escape probability, and ionization fraction using a grid of flare models from radiative hydrodynamic simulations as our dataset. Results. We provide new lookup tables to calculate chromospheric radiative losses for flares. Compared with previous recipes, our recipe provides a better approximation of the detailed radiative losses for flares.

Linking Characteristics of the Polycyclic Aromatic Hydrocarbon Population with Galaxy Properties: A Quantitative Approach Using the NASA Ames PAH IR Spectroscopic Database

Utilizing the data and tools provided through the NASA Ames PAH IR Spectroscopic Database (PAHdb), we study the PAH component of over 900 Spitzer-IRS galaxy spectra. Employing a database-fitting approach, the average PAH size, the PAH size distribution, and PAH ionization fraction are deduced. In turn, we examine their connection with the properties of the host galaxy. We found that PAH population within galaxies consists of middle-sized PAHs with an average number of carbon atoms of = 55, and a charge state distribution of ∼40% ionized—60% neutral. We describe a correlation between the 6.2/11.2 μm PAH ratio with the ionization parameter (), a moderate correlation between the 8.6/11.2 μm PAH ratio and specific star formation rate, and a weak anticorrelation between γ and M *. From the PAHdb decomposition, we provide estimates for the 3.3 μm PAH band, not covered by Spitzer observations, and establish a correlation between the 3.3/11.2 μm PAH ratio with N C. We further deliver a library of mid-IR PAH template spectra parameterized on PAH size and ionization fraction, which can be used in galaxy spectral energy distribution fitting codes for the modeling of the mid-IR PAH emission component in galaxies.

Tuning the optical and electrical properties of HiPIMS-ITO films by variation of annealing temperature

High power impuls magnetron sputtering (HiPIMS) deposits high quality films due to high ionization fraction. In this work, Indium tin oxide (ITO) films are deposited by HiPIMS methord. The effects of annealing temperature under nitrogen environment on the crystal structure, optical properties and electrical properties of ITO films were investigated. The properties of the films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Hall measurement system (Hall), and UV-Vis spectrophotometer. The results showed that the average visible transmittance of the annealed ITO film reached 83.5%. The XRD results show that the ITO film grain size slightly increased after annealing. The mobility increases after annealing. This study proves that HiPIMS deposited ITO thin film is very superior to low temperature processing, and the grown thin film can be used in LEDs and solar cells.

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere.

We investigate the impact of conjugate photoelectrons (CPEs) on the topside (∼600 km altitude) ionosphere at low and midlatitudes using measurements of the ion temperature, density, and composition from the first Republic of China satellite during a period of the high to moderate solar activity (March 1999 to June 2004). Elevated ion temperatures and densities are observed in the dark Northern American‐Atlantic sector during the December solstice and in the Australian sector during the June solstice. The oxygen ion fraction and density are also elevated at these locations. These observations indicate that photoelectrons from the conjugate hemisphere heat the local ionospheric plasma. The morphology of the ion temperature in the winter hemisphere is well represented by the solar zenith angle in the sunlit conjugate hemisphere. The CPE hypothesis for the observed ionospheric heating is confirmed by coincident nighttime enhancements of the far ultraviolet airglow measured by the Global Ultraviolet Imager onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite.

Influence of the magnetic field on the formation of protostellar disks

Abstract We numerically model the collapse of magnetic rotating protostellar clouds with mass of 10 M ⊙ {M}_{\odot } . The simulations are carried out with the help of 2D MHD code Enlil. The structure of the cloud at the isothermal stage of the collapse is investigated for the cases of weak, moderate, and strong initial magnetic field. Simulations reveal the universal hierarchical structure of collapsing protostellar clouds, consisting of the flattened envelope with the qausi-magnetostatc disk inside and the first core in its center. The size of the primary disk increases with the initial magnetic energy of the cloud. The magnetic braking efficiently transports the angular momentum from the primary disk into the envelope in the case, when the initial magnetic energy of the cloud is more than 20% of its gravitational energy. The intensity of the outflows launched from the region near the boundary of the first core increases with initial magnetic energy. The “dead” zone with small ionization fraction, x < 1 0 − 11 x\lt 1{0}^{-11} , forms inside the first hydrostatic core and at the base of the outflow. Ohmic dissipation and ambipolar diffusion determine conditions for further formation of the protostellar disk in this region.

A CRASH simulation of the contribution of binary stars to the epoch of reionization

ABSTRACT We use a set of three-dimensional (3D) radiative transfer simulations to study the effect that a large fraction of binary stars in galaxies during the epoch of reionization has on the physical properties of the intergalactic medium (i.e. the gas temperature and the ionization state of hydrogen and helium), on the topology of the ionized bubbles and on the 21 cm power spectra. Consistently to previous literature, we find that the inclusion of binary stars can speed up the reionization process of H i and He i, while He ii reionization is still dominated by more energetic sources, especially accreting black holes. The earlier ionization attained with binary stars allows for more time for cooling and recombination so that gas fully ionized by binary stars is typically colder than gas ionized by single stars at any given redshift. With the same volume averaged ionization fraction, the inclusion of binary stars results in fewer small ionized bubbles and more large ones, with visible effects also on the large scales of the 21 cm power spectrum.

Stripping features of 2-MeV/u sulfur-ion beams penetrating carbon foils

The dynamics of charge-state fractions of sulfur-ion beams stripped by carbon foils at 2.0 MeV/u is investigated as a function of the initial-ion charge state q0 of the incident beam using experimental data and theoretical calculations. Experimental dependencies of the ion fractions, mean charges and equilibrium foil thicknesses on q0 are explained using the BREIT code, based on the analytical solution of the balance rate equations, as well as the ETACHA code. Experimental equilibrium charge-state distribution is qualitatively reproduced by both codes, demonstrating the capability of their approaches to the density effect. It is shown experimentally and theoretically that the non-equilibrium charge-state fractions and equilibrium foil thicknesses strongly depend on the initial ion charge q0.