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A comprehensive analysis is presented for the diffusivity of oxygen defects and oxygen self-diffusion in ThO$-2$. The migration energy and diffusivity of oxygen defects with nominal charges have been investigated using density functional theory and phonon simulations. The pathway for the lowest migration energy barrier of oxygen vacancies was found to be along the $\langle 100 \rangle$ direction. Neutral and non-neutral oxygen interstitials exhibited direct (interstitial) and indirect (interstitialcy) migration, respectively. The vacancy migration barrier was found to be lowest for the highest charge, while for interstitials, it is lowest when the charge is lowest. The attempt frequencies of defects were calculated using the Eyring and Vineyard theories. These frequencies displayed a similar dependence on the defect charge as the activation barriers. The charge-averaged diffusivity of vacancies and interstitials were also computed. Across all temperatures, the average vacancy diffusivity was found to be greater than that of interstitial, indicating that oxygen vacancies are more mobile than interstitials. Oxygen self- and chemical diffusion coefficients were analyzed by combining t

JD$.$com, one of the world's largest e-commerce platforms, serves over 700 million active users and millions of merchants, with a catalog of tens of billions of SKUs. At this scale, high-quality, structured item knowledge underpins a better consumer experience, lower management costs, and higher operational efficiency-yet producing and serving it poses three industrial-scale challenges: fast-emerging concepts, high-quality knowledge production for massive SKUs, and diverse downstream requirements. To address these challenges, we present the JD Oxygen AI Item Center (Oxygen AIIC), an industrial-scale platform built on LLMs/VLMs for item-knowledge production and service. Oxygen AIIC is built around four core pillars: (i) ontology engineering driven by efficient human-AI collaboration, which supports the dynamic evolution and agile expansion of an ontology with millions of entries; (ii) a "Semantic Search then Discrimination"(S2D) knowledge identification architecture that, combined with throughput improvement strategies, enables scalable, extensible, and high-throughput AI Item Library production for tens of billions of SKUs; (iii) self-evolving item-understanding LLMs/VLMs that impr

Amorphous oxide semiconductors allow scalable electronics, yet high-mobility p-type counterparts remain rare because O-$2p$ valence bands are typically deep and spatially localized. Motivated by recent reports of unusually high hole mobilities in oxygen-deficient \ce{Se}-doped amorphous tellurium oxides ($a$-\ce{TeO$_x$}), we investigated $a$-\ce{TeO$_x$} with and without \ce{Se} doping using machine-learning-accelerated ab initio molecular dynamics with hybrid-functional defect calculations. We find that oxygen depletion drives nanoscale segregation into interpenetrating $a$-Te and $a$-TeO$_2$ domains with distinct roles: Te vacancies in oxide-like/interfacial environments supply holes, while transport is mediated by percolating Te-$5p$ pathways within the $a$-Te subnetwork. Upon doping, we theoretically verify that Se preferentially incorporates into the $a$-Te domains enhancing connectivity. This preference is nontrivial without explicit modeling given that \ce{Se} shares similar electronic structure with both Te and O. We further find that reducing the oxygen content can likewise enhance hole conductivity. Finally, using amorphous SeO$_x$, we show that domain segregation persis

We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centers of the most luminous galaxies, we have constructed the luminosity - central metallicity diagram for spiral galaxies, based on a large compilation of existing data on oxygen abundances of HII regions in spiral galaxies. We found that this diagram shows a plateau at high luminosities (-22.3 < M_B < -20.3), with a constant maximum value of the gas-phase oxygen abundance 12+log(O/H) ~ 8.87. This provides strong evidence that the oxygen abundance in the centers of the most luminous metal-rich galaxies reaches the maximum attainable value of oxygen abundance. Since some fraction of the oxygen (about 0.08 dex) is expected to be locked into dust grains, the maximum value of the true gas+dust oxygen abundance in spiral galaxies is 12+log(O/H) ~ 8.95. This value is a factor of ~ 2 higher than the recently estimated solar value. Based on the derived maximum oxygen abundance in galaxies, we found the oxygen yield to be about 0.0035, depending on the fraction of oxygen incorporated into dust grains.

Oxygen is the most abundant "metal" element in stars and in the cosmos. But determining oxygen abundances in stars has proven challenging, because of the shortage of detectable atomic oxygen lines in their optical spectra as well as observational and theoretical complications with these lines (e.g., blends, 3D, non-LTE). Nonetheless, Ting et al. (2017) were recently able to demonstrate that oxygen abundances can be determined from low-resolution (R$\simeq$2000) optical spectra. Here we investigate the physical processes that enable such a measurement for cool stars, such as K-giants. We show that the strongest spectral diagnostics of oxygen come from the CNO atomic-molecular network, but are manifested in spectral features that do not involve oxygen. In the outer atmosphere layers most of the carbon is locked up in CO, and changes to the oxygen abundance directly affect the abundances of all other carbon-bearing molecules, thereby changing the strength of CH, CN, and C$_2$ features across the optical spectrum. In deeper atmosphere layers most of the carbon is in atomic form, and any change in the oxygen abundance has little effect on the other carbon-bearing molecules. The key phys

The presence of oxygen vacancy, as well as ordering of vacancies plays an important role in determining the electronic, ionic and thermal transport properties of many transition metal oxide materials. Controlling the concentration of oxygen vacancies as well as the structures or domains of ordered oxygen vacancies has been the subject of many experimental and theoretical studies. In epitaxial thin films, the concentration of oxygen vacancies as well as the type of ordering depends on the structure of the support as well as the lattice mismatch between the thin films and the support. The role of temperature induced structural phase transitions on the oxygen vacancy ordering has remained largely unexplored. Here, we use aberration-corrected scanning transmission electron microscopy (STEM) combined with an in-situ cooling experiments to characterize the atomic/electronic structures of oxygen-deficient $La_{0.5}$$Sr_{0.5}$Co$O_{3-δ}$ thin films grown on SrTi$O_{3}$ across the anti-ferrodistortive phase transition of SrTi$O_{3}$ at 105 K. We demonstrate that atomic-resolution imaging and electron energy-loss spectroscopy (EELS) can be used to examine variations in the local density of s

Oxygen abundances in the spiral galaxies expected to be richest in oxygen are estimated. The new abundance determinations are based on the recently discovered ff-relation between auroral and nebular oxygen line fluxes in HII regions. We find that the maximum gas-phase oxygen abundance in the central regions of spiral galaxies is 12+log(O/H)~8.75. This value is significantly lower than the previously accepted value. The central oxygen abundance in the Milky Way is similar to that in other large spirals.

There are views prevalent in the noncovalent chemistry literature that i) the O atom in molecules cannot form a chalcogen bond, and ii) if formed, this bond is very weak. We have shown in this study that these views are not necessarily true since the attractive energy between the oxygen atom of some molecules and several electron rich anionic bases examined in a series of 34 ion-molecule complexes varied from the weak (ca -2.30 kcal/mol) to the ultrastrong (-90.10 kcal/mol). The [MP2/aug-cc-pVTZ] binding energies for several of these complexes were found to be comparable to or significantly larger than that of the well-known hydrogen bond complex [FH...F]- (roughly -40 kcal/mol). The nature of the intermolecular interactions was examined using the quantum theory of atoms in molecules, second order natural bond orbital and symmetric adaptive perturbation theory energy decomposition analyses. It was found that many of these interactions comprise mixed bonding character (ionic and covalent), especially manifest in the moderate to strongly bound complexes. All these can be explained by a bonding to an anti-bonding orbital type donor acceptor charge transfer delocalization. This study,

We present a systematic study of both nuclear radii and binding energies in (even) oxygen isotopes from the valley of stability to the neutron drip line. Both charge and matter radii are compared to state-of-the-art {\it ab initio} calculations along with binding energy systematics. Experimental matter radii are obtained through a complete evaluation of the available elastic proton scattering data of oxygen isotopes. We show that, in spite of a good reproduction of binding energies, {\it ab initio} calculations with conventional nuclear interactions derived within chiral effective field theory fail to provide a realistic description of charge and matter radii. A novel version of two- and three-nucleon forces leads to considerable improvement of the simultaneous description of the three observables for stable isotopes, but shows deficiencies for the most neutron-rich systems. Thus, crucial challenges related to the development of nuclear interactions remain.

Calculations, performed in Thomas-Fermi approximation, show that the energy of a condensed phase of molecular metallic oxygen is lower by 496 kJ/mol than that of an insulator oxygen phase. The insulator phase is separated from a metallic one by energetic barrier of 1165 kJ/mol. This barrier could be overcome by means of electromagnetic irradiation with quantum energy of 12.071 eV or a bit higher. During such a transition the amount of energy equal to 496 kJ/mol is released. It should be extracted from a sample to secure the existence of a metallic phase.

In this article I explain in detail a method for making small amounts of liquid oxygen in the classroom if there is no access to a cylinder of compressed oxygen gas. I also discuss two methods for identifying the fact that it is liquid oxygen as opposed to liquid nitrogen.

We have studied the effects of oxygen on hydrogenated amorphous/crystalline silicon films in terms of their structural and optical properties. Different hydrogenated silicon oxide (SiO:H) and silicon (Si:H) films are fabricated between microcrystalline and amorphous transition region. X-ray diffraction, Raman, FTIR and UV-Vis emission spectrometry have been used to characterize different films. A comparison of the results with those of different types of films like hydrogenated amorphous silicon oxide (a-SiO:H), hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon ($μ$c-Si:H) films reveal their superiority as an excellent substance for solar cell. X-ray diffraction, FTIR and Raman spectral analysis show that difference of the H dilution effect has a major effect on the structure of the film and the optical properties. Photoluminescence analysis of amorphous silicon-oxygen and silicon-hydride alloy films has established their efficient application appropriate as Si based light emitting devices. A large optical band gap of 1.83 eV and appearance of strong photo luminescence at 2.0 eV validates the applicability of a-SiO:H film as a better alternative for the solar cel

We investigate the effect of enhancing gravity on saturated nucleate pool boiling of oxygen for effective gravities of 1g, 6.0g, and 16g (g=9.8 m/s^2) at a saturation pressure of 760 torr and for heat fluxes of 10 ~ 3000 W/m^2. The effective gravity on the oxygen is increased by applying a magnetic body force generated by a superconducting solenoid. We measure the heater temperature (expressed as a reduced superheat) as a function of heat flux and fit this data to a piecewise power-law/linear boiling curve. At low heat flux (<400 W/m^2) the superheat is proportional to the cube root of the heat flux. At higher heat fluxes, the superheat is a linear function of the heat flux. To within statistical uncertainties, which are limited by variations among experimental runs, we find no variation of the boiling curve over our applied gravity range.

We present an astonishingly simple and elegant proof of the celebrated Basel problem.

In this work we present new data that sets strong constraints on the solar oxygen abundance. Our approach, based on the analysis of spectro-polarimetric observations, is almost model-independent and therefore extremely robust. The asymmetry of the Stokes V profile of the 6300 A [OI] and NiI blend is used as an indicator of the relative abundances of these two elements. The peculiar shape of the profile requires a value of EO = 730+/-100 ppm (parts per million), or logEO = 8.86+/-0.07 in the logarithmic scale commonly used in Astrophysics. The uncertainty range includes the model dependence as well as uncertainties in the oscillator strengths of the lines. We emphasize that the very low degree of model dependence in our analysis makes it very reliable compared to traditional determinations.

Blood oxygen saturation (SpO$_2$) is an essential indicator of respiratory functionality and is receiving increasing attention during the COVID-19 pandemic. Clinical findings show that it is possible for COVID-19 patients to have significantly low SpO$_2$ before any obvious symptoms. The prevalence of cameras has motivated researchers to investigate methods for monitoring SpO$_2$ using videos. Most prior schemes involving smartphones are contact-based: They require a fingertip to cover the phone's camera and the nearby light source to capture re-emitted light from the illuminated tissue. In this paper, we propose the first convolutional neural network based noncontact SpO$_2$ estimation scheme using smartphone cameras. The scheme analyzes the videos of a participant's hand for physiological sensing, which is convenient and comfortable, and can protect their privacy and allow for keeping face masks on. We design our neural network architectures inspired by the optophysiological models for SpO$_2$ measurement and demonstrate the explainability by visualizing the weights for channel combination. Our proposed models outperform the state-of-the-art model that is designed for contact-bas

Usually microscopic electrostatic field around ions is neglected when the ionization energy is concerned. The ionization energy is considered to be equal to that of a separate atom (molecule). Here the energy of the electrostatic field around ions is taken into account. It is shown that the energy of this field contributes to decrease in the effective ionization energy. The effective ionization energy may turn to zero at some critical concentration of delocalized electrons. This leads to a complete ionization of the atoms (molecules). Concrete calculations were performed for oxygen molecular gas.

We investigated theoretically electronic and magnetic properties of the perovskite material SrCoO$_{3-δ}$ with $δ\leq 0.15$ using a projector-augmented plane-wave method and a Green's function method. This material is known from various experiments to be ferromagnetic with a Curie temperature of 260$\,$K to 305$\,$K and a magnetic moment of 1.5${\,μ_\text{B}}$ to 3.0${\,μ_\text{B}}$. Applying the magnetic force theorem as it is formulated within Green's function method, we calculated for SrCoO$_{3-δ}$ the magnetic exchange parameters and estimated the Curie temperature. Including correlation effects by an effective $U$ parameter within the GGA$+U$ approach and verifying this by hybrid functional calculations, we obtained the Curie temperatures in dependence of the oxygen deficiency close to the experimental values.

Using spatially resolved, deprojected ROSAT PSPC spectra of 10 of the brightest cooling flow galaxies and groups with low Galactic column densities we have detected intrinsic absorption over energies ~0.4-0.8 keV in half of the sample. Since no intrinsic absorption is indicated for energies below ~0.4 keV, the most reasonable model for the absorber is collisionally ionized gas at temperatures T=10^{5-6} K with most of the absorption arising from ionized states of oxygen but with a significant contribution from carbon and nitrogen. The soft X-ray emission of this warm gas can explain the sub-Galactic column densities of cold gas inferred within the central regions of most of the systems. Attributing the absorption to ionized gas reconciles the large columns of cold H and He inferred from EINSTEIN and ASCA with the lack of such columns inferred from ROSAT. Within the central ~10-20 kpc, where the constraints are most secure, the estimated mass of the ionized absorber is consistent with most (perhaps all) of the matter deposited by a cooling flow over the lifetime of the flow. Since the warm absorber produces no significant H or He absorption the large absorber masses are consistent w