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Ruby is a mineral in the corundum (Al2O3) family and it is remarkably valuable as a gemstone. From the physics point of view, the ruby coloration depends on the balance of trace or chromophore impurities and defect complexes in the Al2O3 lattice. Shifting this balance into right direction is of paramount importance for the ruby value as the gemstone and ion implantation can be applied for this purpose. Thus, in the present study, we explored the influence of high dose oxygen ion implants on the natural ruby coloration. By performing quantitative colorimetry analysis, we detected prominent coloration changes unambiguously attributed to the effect of the implants, even though the implanted oxygen profile was located at the near surface region of the sample. Moreover, applying near surface sensitive cathodoluminescence measurements we observed spectacular changes in the spectra correlated with the implants. Importantly, the trends observed in the colorimetry and cathodoluminescence as a function of the implantation parameters were consistent. As such, the present paper provides both the scientific perspective and quantitative interpretations potentially paving the way for the ion beams applications in the gemstone industry.

Efficient activation of CO2 at low temperature was achieved by reverse water–gas shift via chemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu–In structured oxide, even at lower temperatures. Results show that a novel Cu–In2O3 structured oxide can show a remarkably higher CO2 splitting rate than ever reported. Various analyses revealed that RWGS-CL on Cu–In2O3 is derived from redox between Cu–In2O3 and Cu–In alloy. Key factors for high CO2 splitting rate were fast migration of oxide ions in the alloy and the preferential oxidation of the interface of alloy–In2O3 in the bulk of the particles. The findings reported herein can open up new avenues to achieve effective CO2 conversion at lower temperatures., Efficient activation of CO2 at low temperature was achieved by reverse water–gas shift via chemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu–In structured oxide, even at lower temperatures.

High oxygen ion conductivity of solid electrolytes is a crucial prerequisite for the efficiency of electrochemical devices such as solid oxide fuel cells and rechargeable oxide batteries. Lanthanum...

In this work we present an analysis of the dynamics of suprathermal ions of different masses (H+, He+, O+) during prolonged dipolarizations in the near-Earth magnetotail (X>-17RE) according to Cluster/RAPID observations in 2001–2005. All dipolarizations from our database were associated with fast flow braking and consisted of multiple dipolarization fronts (DFs). We found statistically that fluxes of suprathermal ions started to increase ∼1 min before the dipolarization onset and continued to grow for ∼1 min after the onset. The start of flux growth coincided with the beginning of a decrease in the spectral index γ. The decrease in γ was observed for protons for ∼1 min after the dipolarization onset, and for He+ and O+ ions for ∼3 and ∼5 min after the onset respectively. The negative variations of γ for O+ ions were ∼2.5 times larger than for light ions. This demonstrates more efficient acceleration for heavy ions. The strong negative variations of γ were observed in finite energy ranges for all ion components. This indicates the possibility of nonadiabatic resonant acceleration of ions in the course of their interaction with multiple DFs during dipolarizations. Our analysis showed that some fraction of light ions can be accelerated up to energies ≥600 keV and some fraction of oxygen ions can be accelerated up to ∼1.2 MeV. Such strong energy gains cannot be explained by acceleration at a single propagating DF and suggest the possibility of multistage ion acceleration in the course of their interaction with multiple DFs during the prolonged dipolarizations.

Wedig et al.’s recent experiment (Wedig, A.; Nature Nanotech. 2016, 11, 67.) revealed that the diffusion of both metal (M) and O ions occurs in MOx-based resistance switches. However, the diffusion...

In this paper, we investigated retention failure behavior in analog RRAM devices. The retention failure time was found to be longer in TiW/ Al 2 O 3 /Ta 2 O 5 /Ta device than that of TiW/HfO 2 /Ta 2 O 5 /Ta device. Higher diffusion barrier for oxygen ions/vacancies causes retention time to be longer in a TiW/Al 2 O 3 /Ta 2 O 5 /Ta device. Multiple memory states were observed and found to be stable for at least 104 s at room temperature and this failure time is defined as the time for the resistance variation to remain within 10%.

Oxygen ion implantation has been applied to improve the color quality of the ruby corundum gemstone. Specifically, the color enhancement of the ruby considered in this study was to bring out more redness of the gemstone. Surprisingly, the redness enhancement could be done indirectly by increasing the yellowness while decreasing the blueness of the ruby. However, not all rubies can be improved equally through the oxygen ion implantation technique and each implantation procedure usually takes at least 6 hours. It was of a great need to know the characterization of the rubies that would response well to the oxygen ion implantation. This paper proposed an input-output mathematical model that could predict the levels of color enhancement of rubies via an oxygen ion-implantation. The proposed model described the relationship between two critical chemical compositions, the traced levels of iron and chromium before the treatment as the model inputs and the positive increment in the b* axis (the increment toward yellowness in the yellow-blue axis) being the model output. The model structure was explored using the first, the second and the third order polynomial equations. The parameters were estimated based on the least square method, and the leave-one-out cross validation was used for dealing with a limitation of data points. The prediction performance of three chosen models were measured against the observed data. It was found that the third order model yielded the lowest error while satisfying prediction performance could be observed from the second order models as well.

This study demonstrates the tunability of optical properties of porous silicon (PSi) based optical microcavities by energetic oxygen (O) ion irradiation. The PSi microcavities were irradiated with ion beams of energies: 20 keV and 1 MeV with different ion fluences. The dominant resonant cavity peak exhibits significant redshift up to ∼ 20 nm with irradiation and considerable change in the optical properties. The implanted O ions modulate the surface with Si–Si and Si–O bonds by controlled oxidation of individual PSi layers. These are responsible for the modification in the refractive index and thereby the optical characteristics of the microcavity. The experimental results are supported by ion propagation and transfer-matrix model (TMM) simulations. This study establishes that the energetic O ions can produce controlled tunability to the photonic structures suitable for optoelectronic applications.

Polyethylene terephthalate (PET) films of 50 μm thickness were exposed to swift-heavy 50 MeV copper and 84 MeV oxygen ions, with fluence varying from 1 × 1011 to 1 × 1013 ions cm−2. Differential sc...

The theoretical analysis of oxygen-ion conductivity in double perovskite type oxides was performed. The model of ion transport was developed by considering two energetically non-equivalent oxygen positions for ion jumps in the crystalline structure. The temperature variations of oxygen ion conductivity were shown to depend on thermodynamic parameters of the intrinsic oxygen disordering process. The model proposed was verified by experimental data for perovskite-like non-stoichiometric PrBaCo2O6–δ, Sr3Fe2O7–δ and its titanium-doped derivative.

Carbon and oxygen ions were accelerated simultaneously to estimate the effect of irradiation of living cells with the two different ions. This mixed ion beam was used to irradiate the CHO-K1 cells, and a survival test was performed. The type of the effect of the mixed ion beam on the cells was determined with the isobologram method, whereby survival curves for irradiations with individual ion beams were also used. An additive effect of irradiation with the two ions was found.

International audience; Time of flight secondary ion mass spectrometry (ToF-SIMS) is a well-adapted analytical method for the chemical characterization of concentration profiles in layered or multilayered materials. However, under ion beam bombardment, initially smooth material surface becomes morphologically unstable. This leads to abnormal secondary ion yields and depth profile distortions. In this contribution, we explore the surface topography and roughening evolution induced by O-2(+) ion bombardment on GaSb/InAs multilayers. We demonstrate the formation of nanodots and ripples patterning according to the ion beam energy. Since the latter are undesirable for ToF-SIMS analysis, we managed to totally stop their growth by using simultaneously sample rotation and oxygen flooding. This unprecedented coupling between these two latter mechanisms leads to a significant enhancement in depth profiles resolution.

The novel Cl−-doped compound based on oxygen deficient double perovskite Ba2CaNbO5.5 was synthesized Ba2CaNbO5.48Cl0.05 and its structure, thermal properties, hydration behavior and electrical properties have been investigated. It was found that introduction of Cl− ions leads to the increasing of oxygen ion and proton conductivities. The appearance of donor defect Clo (or Fo ) decreases the activation energy for oxygen ion transport and increases the mobility of oxygen vacancies due to electrostatic repulsion between the positive charged defects Vo and Clo (Fo ). It was shown that Cl−-doping decreases proton concentration but enhances proton conductivity due to significant increase in proton mobility.

Quantitative analysis methods of multi-element alloy films were compared. The atomic fractions of Si 1-x Ge x alloy films were measured by depth profiling analysis with secondary ion mass spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS). Intensity-to-composition conversion factor (ICF) was used as a mean to convert the intensities to compositions instead of the relative sensitivity factors. The ICFs were determined from a reference Si 1-x Ge x alloy film by the conventional method, average intensity (AI) method and total number counting (TNC) method. In the case of SIMS, although the atomic fractions measured by oxygen ion beams were not quantitative due to severe matrix effect, the results by cesium ion beam were very quantitative. The quantitative analysis results by SIMS using MCs 2 + ions are comparable to the results by XPS. In the case of XPS, the measurement uncertainty was highly improved by the AI method and TNC method.

Study of the defect states in the luminescent host materials has always been a significant point in improving the light emitting devices performances. To afford candidate luminescence host materials, defect states in Sr3MgSi2O[Formula: see text]F[Formula: see text] induced by substitution of fluorine ions (F[Formula: see text] substituting for oxygen ions (O[Formula: see text] have been studied through first principles calculation and the related results are presented in this work. First, chemical formulas have been confirmed to be Sr3MgSi2O[Formula: see text]F[Formula: see text] through calculations of the possible crystal structures with increasing F[Formula: see text] substituting for O[Formula: see text] concentrations while band gap values decrease from 5.889 eV to 5.328 eV. When the fluorine ion substituting concentration [Formula: see text] reached 0.5, a new defect state near 3.002 eV in the band gap appeared and it can be concluded that the defect state originates from the two fluorine ions bonding to the same Si–O–F2 group. In addition, there arose a new absorption band in the visible region and it can also be attributed to the introduced color [Formula: see text] center in Sr3MgSi2O[Formula: see text]F. The aforementioned results show that tiny doping amounts of fluorine ions could make Sr3MgSi2O[Formula: see text]F[Formula: see text] suitable for luminescence host materials.

La2Hf2O7 and La2Mo2O9 as potential electrolytes for solid oxide fuel cells (SOFCs) have been investigated through first-principles calculations to understand the mechanism of ion motion. In La2Hf2O7, three unique types of positions that can form anion-Frenkel (a-Fr) pairs have been screened out and a reasonable continuous diffusion path constructed by these migration sites has also been suggested as the dominant cause of ion conduction. On the other side, excellent ion conductivity in La2Mo2O9 is more based on the short-range disorder induced by mobile structure. The thermodynamic properties comparison of La2Mo2O9 and La2Hf2O7 shows that the formation of a-Fr pairs in La2Mo2O9 will start at lower temperature because of higher degree of structural disorder and less constraints on oxygen ions.

UO2 transforms into a superionic conductor at temperatures in excess of 2000 K with oxygen ions becoming mobile and exhibiting collective diffusive dynamics. While the response of UO2 to irradiation is of current interest, the possible impact of superionic characteristics on defect dynamics and recovery following radiation has not been explored yet. In the current work, we use atomistic simulations to elucidate the short-time dynamical response of stoichiometric UO2 subjected to low energy radiation knocks. We observe that the oxygen ions exhibit a collective behavior that is characterized by frequent hopping across their native lattice sites and forming quasi-one-dimensional string-like structures, which are typical of the superionic state. Approximately, a quarter of the displaced oxygen ions dynamically recover through concerted string-like displacements. Our simulations thus suggest a plausible correlation between defect recovery of irradiated UO2 and the characteristic superionic hopping mechanism among the oxygen ions.

The electron paramagnetic resonance (EPR) spectra of Gd3+ impurity centers in CaMoO4 single crystals have been investigated at temperatures T = 1.8, 4.2, and 99–300 K. The temperature dependences of the spin Hamiltonian parameters bn m(T) (n = 2, 4, m = 0, 4) have been determined, and their analysis has been carried out. The temperature contributions from the static lattice, b 2(L) and b 4m(L), to the spin Hamiltonian parameters b n m(T) have been separated. For this purpose, the changes of the static lattice contributions b 2(L) and b 4m(L) have been determined taking into account the temperature shifts of the oxygen ions nearest to the Gd3+ ions in CaMoO4 single crystals. The differences b nm(F) = bn m–b nm(L) have been attributed to the spin–phonon contribution. The analysis of the results obtained has demonstrated that the parameters b 20(F) and b 4m(F) are positive, and the dependence of b 20(F) on the temperature T is well described in the model of local vibrations (G. Pfister). However, the temperature behavior of the parameter b 4m(F) could not be described in the framework of the well-known models of the spin–phonon interaction.

The reactive performance of negative ions evolved in air and O2 atmospheres through a gas-phase chemiluminescence (CL) method was investigated, and was attributed to the reaction between negative oxygen ions (O2−) to evolve emissive singlet oxygen (1O2) species, and a novel CL system was established.

In this work, we report the tunable emission properties of Ce3+ in an apatite-type LiY9(SiO4)6O2 compound via adjusting the doping concentration or temperature. The occupancies of Ce3+ ions at two different sites (Wyckoff 6h and 4f sites) in LiY9(SiO4)6O2 have been determined by Rietveld refinements. Two kinds of Ce3+ f–d transitions have been studied in detail and then assigned to certain sites. The effects of temperature and doping concentration on Ce3+ luminescence properties have been systematically investigated. It is found that the Ce3+ ions prefer occupying Wyckoff 6h sites and the energy transfer between Ce3+ at two sites becomes more efficient with an increase in doping concentration. In addition, the charge-transfer vibronic exciton (CTVE) induced by the existence of free oxygen ion plays an important role in the thermal quenching of Ce3+ at 6h sites. Because of the tunable emissions from cyan to blue with increasing temperature, the phosphors LiY9(SiO4)6O2:Ce3+ are endowed with possible thermom...

In this paper, using data obtained by Cluster 4 satellite from 2001 to 2012, we statistically investigate the spatial distributions of H + and O + in the magnetotail plasmasheet and their relation with geomagnetic indices. Our work outlines the existence of two regions with enhanced O + concentration in the tail plasmasheet, one is located in the mid-tail plasmasheet at R > 17 R E , and the other is located near the inner boundary of plasmasheet at R R E . The existence of the depletion region of O + between 10 R E R R E indicates that the O + ions in the mid-tail plasmasheet, which come from polar cap, are not likely to be able to make important contribution to the formation of ring current. Both the distributions of density and temperature of O + ions have a dawn–dusk asymmetry. The number density of O + during geomagnetic active time ( Dst AE > 200 nT/ Kp ⩾ 3) is much larger than that during non-storm time ( Dst > −20 nT/ AE Kp + varying with geomagnetic activity apply for both regions ( R R E and R > 17 R E ) of O + . Therefore both substorm and enhanced convection provide a large number of O + ions to the plasmasheet, which makes favorable condition for the growth of the ring current.

The X-ray production cross sections induced by oxygen ions with projectile energies from 12.8 to 25.6 MeV for the elements from Al to Bi were measured. The applied approach is based on calculation of X-ray production cross sections through the cross section of Rutherford backscattering, which can be calculated with high accuracy using the Rutherford formula. The experimental results are compared to the predictions of ECPSSR and PWBA theories calculated with the ISICS code.

Indium–tin–oxide (ITO) is investigated as the top electrode material in HfO2-based resistive random access memory cells. Experimental results show that in contrast to a metal (Pt) electrode, an ITO electrode provides for self-limiting current flow during the forming and SET processes, so that no compliance limit is necessary. This provides for low-power consumption, high endurance ( $> 10^{7}$ cycles), and short SET/RESET transition times ( $\sim 50$ ns). We propose that this is because ITO is an oxygen-vacancy-rich material, providing bulk storage for oxygen ions rather than surface storage as a metal electrode.

Oxygen-rich polycrystalline NiOx films were prepared by means of magnetron sputtering. Thickness-dependent bipolar resistive switching behaviors revealed that the 20 nm-thick NiOx film presented a clockwise current-voltage loop, while the 60 nm-thick NiOx film achieved an anti-clockwise current-voltage loop. Redox reactions between penetrated Ag ions and drifted oxygen ions in the whole 20 nm-thick NiOx films resulted in the clockwise current-voltage loops. Filamentary conducting paths composed by oxygen vacancies were responsible for the anti-clockwise resistive switching loops of the 60 nm-thick NiOx film.

Thermoluminescence (TL) of X-rayed LuPO4:Eu sintered materials was investigated as a function of the processing parameters and Eu concentration. Sinterability of the powders precipitated from a water solution was found to be much better than that previously reported for hydrothermally made precursors. The mechanism of the TL process was tracked by means of TL and EPR techniques. It was shown that TL efficacy was greatly dependent upon the processing temperature becoming most potent for pellets sintered at 1700 °C. The most potent TL was obtained for materials containing 2% Eu and sintered in vacuum. The high-temperature treatment appeared to be needed to generate defect states able to participate in energy storage by immobilization of excited carriers. With increasing concentration of the activator ions from 0.1% to 5%, the mechanism of TL in LuPO4:Eu had a continuously more localized character. EPR spectroscopy revealed that Eu3+ attracts excited electrons to the conduction band and gets converted to Eu2+, while a hole is postulated to be trapped on oxygen ions surrounding a vacant Lu site.

Normally, the Martian ionosphere displays a dusk enhancement due to continuous depletion of plasma via recombination during day-to-night transport. Using the extensive measurements made by the Neutral Gas and Ion Mass Spectrometer on board the Mars Atmosphere and Volatile Evolution spacecraft, we show that several species, including , OH+, H2O+, and NH+, present instead an abnormal dawn enhancement above the exobase where they are mainly produced by ion-neutral reactions involving H2. Such a peculiarity is indicative of a dawn bulge of H2 present in the Martian upper atmosphere and corona, which is driven by subsidence in regions of horizontal wind convergence and the subsequent buildup of minor atmospheric species with large vertical scale heights. A similar dynamical process is also known to occur in the upper atmospheres of other solar system bodies such as the Earth, Venus, and Titan. Interestingly, despite that the diurnal variations of O and N are subject to the same dynamical effect, a dawn enhancement is not seen for O+ and N+, possibly due to the nonthermal production of their parent atoms in the ambient atmosphere via processes such as photodissociation and dissociative recombination. The H2 distribution inferred in this study is important for a thorough understanding of hydrogen escape and climate evolution on Mars.

The properties of secondary particles for sputtering silicon with primary low-energy oxygen ions were investigated with dependence on the primary ion energy Eion and geometric parameters (ion incidence angle, polar emission angle, and scattering angle). The mass and energy distributions of the secondary particles were measured by energy-selective mass spectrometry. The experimental results were compared with simulations using the Monte Carlo code sdtrimsp and with calculations based on a simple elastic binary collision model. The main secondary ion species were found to be O+, O2+, Si+, and SiO+. Their energy distribution functions depend on the primary ion energy Eion and the scattering angle γ. For O+, Si+, and SiO+ ions, a decreasing scattering angle γ or an increasing primary ion energy Eion leads to a pronounced feature in the high-energy part of the distributions. The energy distributions of the secondary O2+ ions show hardly any changes with regard to the primary ion energy or the scattering angle γ. In the case of the O+ ions, the energy distribution appears to reflect several direct scattering channels, which could be associated with the primary ion energy Eion, and half of the ion energy Eion/2. The present experimental results are compared with previous investigations for the sputtering of Si with the noble gas ions, such as Ne+, Ar+, and Xe+.

Using the multiband $d\text{\ensuremath{-}}p$ model and unrestricted Hartree-Fock approximation we investigate the electronic structure and spin-orbital order in a three-dimensional ${\mathrm{VO}}_{3}$ lattice. The main aim of this paper is testing if a simple $d\text{\ensuremath{-}}p$ model with partly filled $3d$ orbitals (in vanadium ions) and $2p$ orbitals (in oxygen ions) is capable of reproducing correctly nontrivial coexisting spin-orbital order observed in the vanadium perovskites. We point out that the multiband $d\text{\ensuremath{-}}p$ model has to include partly filled ${e}_{g}$ orbitals in vanadium ions. The results suggest weak self-doping as an important correction beyond the ionic model and reproduce the possible ground states with broken spin-orbital symmetry in vanadium ions: either $C$-type alternating orbital order accompanied by $G$-type antiferromagnetic spin order or $G$-type alternating orbital order accompanied by $C$-type antiferromagnetic spin order. Both states are experimentally observed and compete with each other in ${\mathrm{YVO}}_{3}$ whereas only the latter was observed in ${\mathrm{LaVO}}_{3}$. Orbital order is induced and stabilized by particular patterns of oxygen distortions arising from the Jahn-Teller effect. In contrast to time-consuming ab initio calculations, the computations using the $d\text{\ensuremath{-}}p$ model are very quick and should be regarded as very useful in solid-state physics, provided the parameters are selected carefully.

In this paper, there are presented the studies’ results of the structures and magnetic properties of the (1 − x)BiFeO3–xPbFeO3 solid solutions with x = 0.05; 0.10; 0.15; 0.20; 0.25; 0.30; 0.50. It has been established that at room temperature in the compositions x = 0.05 and x = 0.10, there is a rhombohedral phase of R3c, in the compositions with x = 0.15–0.30 there exists a pseudocubic phase of Pm-3m and there is a rhombohedral phase of R-3c in the composition with x = 0.50. Using the γ-resonance method, it has been established that the Fe3+ ions are present in all the compositions, which corresponds to the non-stoichiometry of the oxygen ions.

Ion bombardment is a key physical process in the ion implantation and irradiation of graphene, with important implications for tuning graphene’s electronic properties and for understanding the material’s behavior in irradiative environment. Using molecular dynamics with a reactive force field, this work systematically investigates the influence of the incident angle on the generation of defects and vacancies during the bombardment process. It is found that larger incident angles (between the incident line and the surface of graphene) ranging from 70° to 90° are desired for substitution and single vacancy, whereas smaller incident angles ranging from 30° to 50° are favored for forming double vacancies, multiple vacancies, and in-plane disorder. Oxygen ions with the incident angle of 70° produce the highest probability of ion substitution, and the ions at 40–60 eV and 70° yield the highest quality of doping with minimum other defects. These results demonstrate that bombarding graphene along oblique directio...

Pattern formation on surfaces of III–V compound semiconductors GaAs, GaSb, and InSb by O 2 + ion sputtering was studied. For GaAs, a ripple pattern was observed under a 2-keV primary beam energy for two ion fluences, i.e., 3.1×1018 ions/cm2 and 5.4×1018 ions/cm2. The pattern wavelengths were 175 nm and 200.2 nm. A bubble-like structure was observed on the GaSb surface bombarded with 1-keV and 2-keV oxygen ions. In the case of InSb, several pyramidal structures with sub-micrometer dimensions were observed when the ion energy was 1 keV. When the ion energy was increased to 2 keV, the pyramidal structures acquired micrometer dimensions and a ripple pattern with a wavelength of 246 nm was observed in the surrounding area.

The effect of the negative oxygen ions in direct current magnetron sputtering on the thin film deposition is investigated with a two-dimensional particle-in-cell simulation with the variation of argon gas pressure ranging from 1.33 to 6.67 Pa (10 to 50 mTorr). While the plasma density increases with the increase of gas pressure, the total amount of the negative oxygen ions emitted from the target surface does not change significantly with respect to the gas pressure. The amount of high energy O − ions having small incident angles on the substrate decreases with increasing gas pressure especially at the target erosion region. On the contrary, the amount of low energy O − ions having large incident angles on the substrate increases with increasing gas pressure especially at the center region. The tendency for the change of spatial resistivity of ZnO thin films with respect to gas pressure can be explained with the simulation results.

We report here the results of Molecular Dynamics simulations of the drift mobility of negative oxygen ions in very dense neon gas in the supercritical phase. The simulations relatively well reproduce the trend of the experimental data. The rationalization of the mobility behavior as a function of the gas density is given in terms of the number of atoms correlated in the first solvation shell around the ion.

The work reports the effect of 80MeV 6+ Oxygen ion irradiation on the performance of DSSCs. TiO2 coated FTO were subjected to ion irradiation of fluences 1 × 1012 to 1 × 1014 ions/cm2. TiO2 coated FTOs were characterized with XRD for structural analysis and have shown anatase phase. Irradiated films were used as electrodes for DSSCs. We have observed that the irradiated light conversion efficiency of the cells was highest for fluence of 1 × 1013ions/cm2 and at the same fluence the cell parameters showed to be the best. The reason may be due to the surface modification of the TiO2 coated films due to irradiation. However lower fluences than 1 × 1013 ions/cm2 show less effect while higher fluence shown degrading effect on the cell performance which may be due to the worsening of contact between electrode and dyes.

The abnormal interface artifact with two intense spikes was observed in secondary ion mass spectrometry depth profiling analysis of Si/Ge multilayer films by oxygen ion beam at the sputtering conditions where the Si surface is partially oxidized. The detailed step-by-step variations of the secondary ion intensities were investigated from the interface locations determined by the compositional depth profiles. Selective accumulation of the oxygen ions in the reactive Si layer and the implantation depth was suggested as the origin of the two-step interface artifact. The distances between the interfaces and the second spikes were well correlated with the implantation depth of the projected ions. Copyright © 2014 John Wiley & Sons, Ltd.

Purpose: The main advantages of charged particle radiotherapy compared to conventional X-ray external beam radiotherapy are a better tumor conformality coupled with the capability of treating deep-seated radio-resistant tumors. This work investigates the possibility to use oxygen beams for hadron therapy, as an alternative to carbon ions. Materials and Methods: Oxygen ions have the advantage of a higher relative biological effectiveness (RBE) and better conformality to the tumor target. This work describes the mixed radiation field produced by an oxygen beam in water and compares it to the one produced by a therapeutic carbon ion beam. The study has been performed using Geant4 simulations. The dose is calculated for incident carbon ions with energies of 162 MeV/u and 290 MeV/u, and oxygen ions with energies of 192 MeV/u and 245 MeV/u, and hence that the range of the primary oxygen ions projectiles in water was located at the same depth as the carbon ions. Results: The results show that the benefits of oxygen ions are more pronounced when using lower energies because of a slightly higher peak-to-entrance ratio, which allows either providing higher dose in tumor target or reducing it in the surrounding healthy tissues. It is observed that, per incident particle, oxygen ions deliver higher doses than carbon ions. Conclusions: This result coupled with the higher RBE shows that it may be possible to use a lower fluence of oxygen ions to achieve the same therapeutic dose in the patient as that obtained with carbon ion therapy.

Ceramic Fuel Cells Ceramic ion conductors can be used as electrolytes in fuel cells using natural gas. One drawback of such solid-oxide fuel cells that conduct oxygen ions is their high operating temperatures (at least 600°C). Duan et al. have made a proton-conducting ceramic fuel cell with a modified cathode material that exhibits high performance on methane fuel at 500°C (see the Perspective by Gorte). Science , this issue p. [1321][1]; see also p. [1290][2] [1]: /lookup/doi/10.1126/science.aab3987 [2]: /lookup/doi/10.1126/science.aad0432

The relationship between the optical phonon parameters and the oxygen ion conductivities were investigated for AlYb co-doped zirconia ceramics. Intrinsic intragrain ion conductivity, σdc, decreased with increasing Al loading into ytterbia-stabilized zirconia, while the damping parameter of the lattice vibration, γ1TO, increased. This phenomenon agreed with findings of our previous study, which revealed a relationship between the σdc and the γ1TO for zirconia-based ion conductors.

In this paper, the polyester chips were crystallized, dried up, grinded into power, mixed with dispersant and anionic powder whose surface has been modified. The conventional properties and capacity of releasing anion for the anionic functional PET fiber were studied. It was found that, as adopted the compound dispersant A+B, the intrinsic viscosity of the PET chips is about 0.72, the dispersibility and the spinnability is good, and the activity of the anionic powder is higher. The breaking strength of the anionic PET fiber decreases from 3.2cN/dtex to 2.6cN/dtex when the content of the anionic functional filler increases from 2 to 4 wt%. However, with increasing the anionic functional filler content, the capacity of releasing anion for the functional PET fiber increases and the number of the negative oxygen ion is 1430 / cm3, which is about two times when the content of anionic functional filler increases from 2 wt% to 4wt%.

The yellow color of beryl has been related to charge-transfer between Fe 3+ ions substituting for octahedral Al 3+ ions in the crystal and the surrounding oxygen ions. This assumption is contradicted by results from Electron Paramagnetic Resonance (EPR) measurements. A strong EPR signal from octahedral Fe 3+ ions can be found in beryl of all colors and in colorless beryl. An EPR signal unique to yellow beryl comes from Fe 3+ ions at a tetrahedral site. I propose that the yellow color of beryl comes from charge-transfer of tetrahedral Fe 3+ ions. A simple model involving electrons trapped in the crystal structure explains the creation and the decay of the yellow color. The absence of trapped electrons in dark red beryl can explain the high temperature stability of its color. There is no evidence that iron ions are located in the channels of the beryl structure, which has often been assumed.

Transmission of O 6+ ions through a tapered glass capillary with a diameter of 0.2 mm at the exit has been investigated, in which high incident current with a magnitude of several nA/mm 2 was employed. The majority of ions passing through the capillary deviated from their incident directions, but kept their charge state and energy even when the capillary was tilted with an angle less than the opening angle. The present results indicate that the focusing effect can also be obtained in the transmission of medium energy ions through a tapered glass macrocapillary and show a rough linear relationship between the transmission probability and the ions perpendicular energy.

In order to study the influence of factors on the released anion concentration, the factors include the fiber content of negative oxygen ions, warp and weft density, organizational structure and friction time. Fabrics for A and B series were blended with modified polyester negative oxygen ions fiber and viscose fiber in different blending ratio. The released anion concentration were tested and analyzed. From the test results, following conclusions can be gotten. 1) In the same circumstance of other process conditions, with increasing of negative oxygen ions fiber content, the released anion concentration increased; 2) The honeycomb weave fabric B5 released the highest anion concentration in the other same process conditions, while plain weave fabric B1 released the least concentration; 3) More negative oxygen ions were produced when the warp and weft density were greater; 4) As the time of friction increased, the released anion concentration of fabric was increased until it reached a stable value; 5) Organizational structure had a great effect on releasing anion concentration through friction between woven fabric of negative oxygen ions and other knitted fabric. When the organization structure had bumpy effect, it was more conducive to release negative oxygen ions.

A structurally-based viscosity model (using a few optimized parameters) is proposed to represent viscosity as functions of both temperature and composition for the CaO–MgO–Al2O3–SiO2. The model represents the slag structure through the different types of oxygen ions formed in the melt. Approximate methods for calculating the concentrations of these different types of oxygen ions are proposed and are then used to describe the effect of melt structure on viscosity. The model provides a good description of the viscosity behavior varied with composition and temperature within the CaO–MgO–Al2O3–SiO2 system. This includes pure systems: Al2O3 and SiO2; binary systems: CaO–SiO2, MgO–SiO2, Al2O3–SiO2 and CaO–Al2O3; ternary systems: CaO–MgO–SiO2, CaO–Al2O3–SiO2 and MgO–Al2O3–SiO2; quaternary system: CaO–MgO–Al2O3–SiO2. The different roles of CaO and MgO on viscosity are also discussed; these tend to differ in melts with or without Al2O3. In the absence of Al2O3, CaO reduces the viscosity more than MgO. In contrast, when Al2O3 is present, the Ca2+ ions take priority over Mg2+ ions in the charge-compensation of Al3+ ions which leads to the formation of more stable Ca–AlO45– tetrahedral structures, which, in turn, results in an increase in viscosity. However, when there is enough basic oxide (CaO or MgO) present to generate non-bridging oxygens, CaO reduces the viscosity more effectively than MgO.

Single crystalline langatate (LTG, La 3 Ta 0.5 Ga 5.5 O 14 ) has been widely used as a sensor material in high temperature applications because of its thermally stable piezoelectric properties. In this research, to elucidate the relationship between piezoelectric tensors and local ionic configurations, first-principles calculations based on density functional perturbation theory (DFPT) were performed on various local ionic structures. The results indicate that two independent relaxed-ion piezoelectric coefficients, e 11 and e 14 , increased with increases in La ( 3e ) –O and Ta ( 1a ) –O distances or decreases in Ga ( 3f , 2d ) –O distances. Thus, to obtain high piezoelectric constants in this crystal, ions larger than La 3+ should be incorporated at 3e sites to open the distance between 3e ions and oxygen ions, and ions smaller than Ga 3+ should be introduced at 2d and 3f sites to reduce the distance between Ga and O ions. Finally, from this design rule, a new crystal, BTAS (Ba 3 TaAl 3 Si 2 O 14 ), which belongs to the same P321 group, is proposed. The calculated relaxed-ion piezoelectric coefficient e 11 of BTAS was 17.7% higher than the coefficient of a LTG crystal. This significant increase confirms BTAS as a useful new piezo-material, especially in applications where there is also a need to reduce the use of more expensive elements.

Fe-25wt%Cr alloys were fabricated by combining Powder Metallurgy (PM) with hot-forging treatment, and their oxidation behavior at 1100°C in air was investigated systematically by using XRD, SEM and EDS, respectively. The results showed that a composite oxidation scale containing both Cr2O3and FeCr2O4formed on the surface of as-forged Fe-25wt%Cr alloys after oxidation at 1100°C in air for 100 hours. The oxidation process of Fe-Cr alloys could be obviously divided into two different stages, and the kinetics of two-stage oxidation agreed well with the parabolic law. The first could be corresponding to the formation of protective Cr2O3layer, while the second could be thought as the growth of FeCr2O4and the further oxidation of the inner Cr2O3oxidation scale. The faster oxidation rate in the second stage could be attributed to both the diffusion of iron ions rapider than that of Cr in the Cr2O3layer and the fast transport velocity of oxygen ions along the cracks.

A semi-empirical effective interionic potential model has been parameterized to investigate UO 2 by molecular dynamics simulation technique. The simulations were performed in the constant pressure–temperature ensemble between 300 K–3200 K at 100 K intervals. The pair distribution functions and coordination numbers signal the onset of structural changes at temperatures in accord with the Bredig transition and melting. The oxygen ion diffusion coefficients calculated from the mean square displacements markedly increase the liquid like value at T > 2100 K . The transition to the superionic state and melting are well reproduced within the limitations of a rigid ion potential.

The possibility of minimizing matrix effects during the SIMS depth profiling of multilayer metal structures is investigated, based on the use of cluster secondary ions that include a combination of the element to be analyzed and sputtering cesium or oxygen ions. For Pd/B4C, Ni/C, and Cr/Sc structures, the use of cluster secondary ions enabled us to substantially enhance depth resolution up to 1–2 nm.