Atomistic Modeling of Natural Gas Desulfurization Process Using Task-Specific Deep Eutectic Solvents Supported by Graphene Oxide.

This study employs Density Functional Theory (DFT) calculations and traditional all-atom Molecular Dynamics (MD) simulations to reveal atomistic insights into a task-specific Deep Eutectic Solvent (DES) supported by graphene oxide with the aim of mimicking its application in the natural gas desulfurization process. The DES, composed of N,N,N',N'-tetramthyl-1,6-hexane diamine acetate (TMHDAAc) and methyldiethanolamine (MDEA) supported by graphene oxide, demonstrates improved efficiency in removing hydrogen sulfide from methane. Optimized structure and HOMO-LUMO orbital analyses reveal the distinct spatial arrangements and interactions between hydrogen sulfide, methane, and DES components, highlighting the efficacy of the DES in facilitating the separation of hydrogen sulfide from methane through DFT calculations.

Color Centers in BaFBr Crystals: Experimental Study and Theoretical Modeling.

This study presents theoretical and experimental investigations into the electron and hole color centers in BaFBr crystals, characterizing their electronic and optical properties. Stoichiometric BaFBr crystals grown by the Steber method were used in the experiments. Radiation defects in BaFBr crystals were created by irradiation with 147 MeV Kr ions with up to fluences of 10-10 ions/cm.

Electronic Structure of Mg-, Si-, and Zn-Doped SnO Nanowires: Predictions from First Principles.

We investigated the electronic structure of Mg-, Si-, and Zn-doped four-faceted [001]- and [110]-oriented SnO nanowires using first-principles calculations based on the linear combination of atomic orbitals (LCAO) method. This approach, employing atomic-centered Gaussian-type functions as a basis set, was combined with hybrid density functional theory (DFT). Our results show qualitative agreement in predicting the formation of stable point defects due to atom substitutions on the surface of the SnO nanowire.

Density functional theory for doped TiO: current research strategies and advancements.

Since the inception of the density functional theory (DFT) by Hohenberg and Kohn in 1964, it rapidly became an indispensable theoretical tool across various disciplines, such as chemistry, biology, and materials science, among others. This theory has ushered in a new era of computational research, paving the way for substantial advancements in fundamental understanding. Today, DFT is routinely employed for a diverse range of applications, such as probing new material properties and providing a profound understanding of the mechanisms underlying physical, chemical, and biological processes.

Electronic, Optical, and Vibrational Properties of an AgAlS Crystal in a High-Pressure Phase.

The aim of this study is to comprehensively examine the structural composition and properties of the AgAlS crystal during its high-pressure phase. This analysis delves into the second coordination environment of the crystal structure and elucidates the distinct transformations it undergoes during the phase transition. The band energy structure was calculated, and the origin of electronic levels was clarified.

Electron Beam-Assisted Synthesis of YAG:Ce Ceramics.

In this work, we present the results of the structure and luminescence properties of YAG:Ce (YAlO doped with Ce ions) ceramic samples. Their synthesis was carried out by sintering samples from the initial oxide powders under the powerful action of a high-energy electron beam with an energy of 1.4 MeV and a power density of 22-25 kW/cm.

Ir impurities in [Formula: see text]- and [Formula: see text]-[Formula: see text] and their detrimental effect on p-type conductivity.

Recently gallium oxide ([Formula: see text]) has become one of the most actively studied materials due to its competitive electronic properties such as wide bandgap, high breakdown field, simple control of carrier concentration, and high thermal stability. These properties make gallium oxide a promising candidate for potential applications in high-power electronic devices. [Formula: see text]-[Formula: see text] crystals are commonly grown by the Czochralski method in an iridium (Ir) crucible.

Electronic and Optical Properties of Rocksalt MgZnO and Wurtzite ZnMgO with Varied Concentrations of Magnesium and Zinc.

The structural, electronic and optical properties of rocksalt Mg1-xZnxO and wurtzite Zn1-xMgxO with the concentration of Zn and Mg varying from 0.125 to 0.875 were investigated using density functional theory (DFT), DFT+U, linear response theory and the Bethe-Salpeter equation.

Influence of Stress on Electronic and Optical Properties of Rocksalt and Wurtzite MgO-ZnO Nanocomposites with Varying Concentrations of Magnesium and Zinc.

The structural, electronic and optical properties of stressed MgO-ZnO nanocomposite alloys with concentrations of Zn and Mg varying from 0.125 to 0.875 were studied using ab initio simulations.

Positron Annihilation Lifetime Spectroscopy Insight on Free Volume Conversion of Nanostructured MgAlO Ceramics.

Herein we demonstrate the specifics of using the positron annihilation lifetime spectroscopy (PALS) method for the study of free volume changes in functional ceramic materials. Choosing technological modification of nanostructured MgAlO spinel as an example, we show that for ceramics with well-developed porosity positron annihilation is revealed through two channels: positron trapping channel and ortho-positronium decay. Positron trapping in free-volume defects is described by the second component of spectra and ortho-positronium decay process by single or multiple components, depending on how well porosity is developed and on the experimental configuration.

Time-Dependent Density Functional Theory Calculations of N- and S-Doped TiO Nanotube for Water-Splitting Applications.

On the basis of time-dependent density functional theory (TD-DFT) we performed first-principle calculations to predict optical properties and transition states of pristine, N- and S-doped, and N+S-codoped anatase TiO2 nanotubes of 1 nm-diameter. The host O atoms of the pristine TiO2 nanotube were substituted by N and S atoms to evaluate the influence of dopants on the photocatalytic properties of hollow titania nanostructures. The charge transition mechanism promoted by dopants positioned in the nanotube wall clearly demonstrates the constructive and destructive contributions to photoabsorption by means of calculated transition contribution maps.

First Principles Calculations of Atomic and Electronic Structure of TiAl3+- and TiAl2+-Doped YAlO.

In this paper, the density functional theory accompanied with linear combination of atomic orbitals (LCAO) method is applied to study the atomic and electronic structure of the Ti and Ti ions substituted for the host Al atom in orthorhombic bulk YAlO crystals. The disordered crystalline structure of YAlO was modelled in a large supercell containing 160 atoms, allowing simulation of a substitutional dopant with a concentration of about 3%. In the case of the Ti-doped YAlO, compensated -center (oxygen vacancy with two trapped electrons) is inserted close to the Ti to make the unit cell neutral.

2D Slab Models of Nanotubes Based on Tetragonal TiO Structures: Validation over a Diameter Range.

One-dimensional nanomaterials receive much attention thanks to their advantageous properties compared to simple, bulk materials. A particular application of 1D nanomaterials is photocatalytic hydrogen generation from water. Such materials are studied not only experimentally, but also computationally.

First-Principles Evaluation of the Morphology of WS Nanotubes for Application as Visible-Light-Driven Water-Splitting Photocatalysts.

One-dimensional tungsten disulfide (WS) single-walled nanotubes (NTs) with either achiral, i.e., armchair (, ) and zigzag-type (, 0), or chiral (2, ) configuration with diameters > 1.

Electronic and optical properties of pristine, N- and S-doped water-covered TiO nanotube surfaces.

For rational design and improvement of electronic and optical properties of water-splitting photocatalysts, the ability to control the band edge positions relative to the water redox potentials and the photoresponse as a function of environmental conditions is essential. We combine ab initio molecular dynamics simulations with ab initio many-body theoretical calculations to predict the bandgap and band edge energies, as well as the absorption spectrum of pristine and N- and S-doped TiO nanotubes using the DFT+U and GW approaches. Both levels of theory show similar trends, and N+S-codoping appears to be the optimal system for photocatalytic water splitting both in dry and humid conditions.

Fast-Response Single-Nanowire Photodetector Based on ZnO/WS Core/Shell Heterostructures.

The surface plays an exceptionally important role in nanoscale materials, exerting a strong influence on their properties. Consequently, even a very thin coating can greatly improve the optoelectronic properties of nanostructures by modifying the light absorption and spatial distribution of charge carriers. To use these advantages, 1D/1D heterostructures of ZnO/WS core/shell nanowires with a-few-layers-thick WS shell were fabricated.

Water Adsorption on Clean and Defective Anatase TiO (001) Nanotube Surfaces: A Surface Science Approach.

We use ab initio molecular dynamics simulations to study the adsorption of thin water films with 1 and 2 ML coverage on anatase TiO (001) nanotubes. The nanotubes are modeled as 2D slabs, which consist of partially constrained and partially relaxed structural motifs from nanotubes. The effect of anion doping on the adsorption is investigated by substituting O atoms with N and S impurities on the nanotube slab surface.

First-principles calculations on Fe-Pt nanoclusters of various morphologies.

Bimetallic FePt nanoparticles with L1 structure are attracting a lot of attention due to their high magnetocrystalline anisotropy and high coercivity what makes them potential material for storage of ultra-high density magnetic data. FePt nanoclusters are considered also as nanocatalysts for growth of carbon nanotubes of different chiralities. Using the DFT-LCAO CRYSTAL14 code, we have performed large-scale spin-polarized calculations on 19 different polyhedral structures of FePt nanoparticles in order to estimate which icosahedral or hcp-structured morphology is the energetically more preferable.

[Clinical and roentgenological manifestations of the silent sinus syndrome].

Analysis of the results of the examination and treatment of four patients presenting with the silent sinus syndrome provided materials for the generalized characteristic of clinical and roentgenological manifestations of this condition.

[Peculiarities of surgical interventions for the treatment of inflammatory and traumatic lesions in the frontal sinus].

This paper summarizes the experience with the treatment of 275 patients presenting with inflammatory diseases and traumatic lesions of the frontal sinus. Based on the results of the present study, recommendations have been developed designed to optimize surgical interventions for the enhancement of treatment efficiency and the prevention of relapses.

[New data on nasal morphology and morphological structure of paranasal sinuses].

The authors summarize the results of investigations of specific anatomical features of paranasal sinuses in more than 12,000 subjects. The patients with suspected cerebral pathology and lesions in the paranasal sinuses were examined using computed tomography. Structural variants of ethmoid bone and ethmoidal labyrinth, nasal septum, maxillary, frontal, and sphenoidal sinuses are described.

The electronic properties of an oxygen vacancy at ZrO(2)-terminated (001) surfaces of a cubic PbZrO(3): computer simulations from the first principles.

Combining B3PW hybrid exchange-correlation functional within the density functional theory (DFT) and a supercell model, we calculated from the first principles the electronic structure of both ideal PbZrO(3) (001) surface (with ZrO(2)- and PbO-terminations) and a neutral oxygen vacancy also called the F center. The atomic relaxation and electronic density redistributions are discussed. Thermodynamic analysis of pure surfaces indicates that ZrO(2) termination is energetically more favorable than PbO-termination.

[Effects of the size and position of the anastomoses on pathological process in the paranasal sinuses].

In small anastomoses of the paranasal sinuses blocking in inflammation we observe acute pyo-exudative inflammation; in large anastomoses--chronic productive form with development of the cysts and polyps. By the authors' experience, 8-10% of the population have no maxillary anastomosis in the crescentic fissure. It locates in the posterior part of its medial wall.