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It is shown that the classical theory of phase transitions is inapplicable for the accurate description of melting processes in nanocrystals. In the paper, the theory of non-classical vacancies is used for this description. In particular, the energy of a nanocrystal containing such defects is evaluated. It is found that the nanocrystal lattice loses its mechanical stability at a certain temperature, T F. This loss of stability is associated with the melting process, and the temperature, T F , is considered as the nanocrystal melting point. At some conditions (for some range of nanocrystal sizes), this temperature may increase with the decrease of the nanocrystal size that agrees with the results of recent experimental studies. [ABSTRACT FROM AUTHOR]

Defect states in nitrogen‐containing float‐zone silicon are investigated in both n‐ and p‐type materials using both deep‐level transient spectroscopy (DLTS) and minority‐carrier transient spectroscopy (MCTS). This enables a mapping of the defect landscape in the entire electronic bandgap and an investigation of whether the properties of the defects depend on the semiconductor type. Two defects, the E1/E2 pair and the E4/E6 pair, are investigated, and no evidence is found for the defect properties to depend on the semiconductor type. [ABSTRACT FROM AUTHOR]

To selectively control the electrical resistance, thin films of TiO2 were irradiated with a YVO4 third‐harmonic generation pulse laser in various power conditions. It was observed that when the laser power was less than 0.26 W, the electrical resistance of thin films decreased with the increase in laser power, whereas when the laser power was more than 0.26 W, the electrical resistance increased as the laser power increases. The minimum electrical resistance of the irradiated thin film was found to be four orders of magnitude lower than that of the unirradiated thin film. X‐ray absorption fine structure analysis revealed that the valence of Ti ions in the thin films was reduced after laser irradiation, indicating the formation of oxygen vacancies with electron doping. The cross‐sectional observation by a scanning electron microscope revealed that high laser power irradiation caused the thin films to become porous, and the percolation theory explains the origin of the increase in electrical resistance with developing porous structure. We propose a phase diagram to completely explain the relationship between electrical resistance and laser power, which supply a guideline on laser modification in TiO2 electrical resistance. [ABSTRACT FROM AUTHOR]

Supreme Court vacancies are now characterized by great partisan efforts to confirm—or impede—the nomination. Amid a politicized vacancy before the 2020 election, there was cause to question the conclusion that these vacancies do not harm the judiciary in the public's eyes. We utilize panel data collected before and after Justice Ginsburg's death to investigate the effects of the vacancy and partisan posturing to fill it. We find that the battle over the vacancy yielded decreases in diffuse support among Democrats, particularly among those who read a story about Senate Republicans' willingness to fill an election-year vacancy after refusing to in 2016. Support for federal judicial elections decreased across survey waves, but only among certain subsets of respondents. Finally, belief that one's preferred 2020 candidate would nominate the next justice significantly influenced support for curbing. Elected branch politics appear capable of influencing the mass public's level of support for the Court. [ABSTRACT FROM AUTHOR]

This investigation studies the influences of Lu substitution for Gd on the structure, vacancy defects, and magnetic properties in GdMnO3 ceramics synthesized using solid state reaction method. The structure measurements indicate that all of the Gd1-xLuxMnO3 ceramics show single-phase structure, the introduction of Lu3+ ions induces structure distortion. All samples with irregular grain shape have relatively dense microstructure, and the Lu3+ ions substitution promotes the grain growth. Positron annihilation experimental results indicate that Lu3+ ions substitution can influence the vacancies size and concentration, and the vacancies concentration increases with the increase of Lu3+ concentration. The evolution of the temperature and magnetic field–dependent magnetization curves presents that Lu3+ ions substitution could obviously affect the magnetic state of GdMnO3, improve the magnetic transition temperature, and magnetization of Gd1-xLuxMnO3. It is found that the enhanced magnetization of Gd1-xLuxMnO3 has a close relationship with vacancies concentration. [ABSTRACT FROM AUTHOR]

Preaging (PA) is an industrial routine that suppresses the deleterious effect of natural aging and enhances the final paint‐bake hardening of 6XXX aluminum alloys. In view of the different advantages of PA at high and low temperatures, the effects of performing PA in two steps at different temperatures, namely, 80 and 160 °C, are explored. Various two‐step PA combinations are investigated, involving both the temperature orders and various aging times at both temperatures, while aiming at the same hardness after all PA treatments. These results are interpreted on the basis of cluster formation and vacancy evolution during two‐step PA. In particular, the first PA step is found to play a more important role than suggested by the durations of the two PA steps as the clusters formed in the first step can strongly influence the subsequent evolution of both clusters and vacancies in the second step. It is found that two‐step PA results in a compromise between the effects of one‐step PA at both temperatures, that is, the enhancement of natural secondary aging stability is accompanied by a reduced paint‐bake hardening or vice versa. [ABSTRACT FROM AUTHOR]

Topological insulators (TI) are a class of materials characterized by metallic edge states protected by time reversal symmetry from local perturbations such as defects while having a bulk insulating gap. Since the topological surface states are exposed to the environment, gas sensing applications could benefit from the higher carrier mobility of the topological surface states. In this work, we study the resistance response of Sb 2 Te 2 Se towards NO 2 and the effects of vacancies introduced by annealing. We found that the vacancies greatly enhance the response and inferred the significant role the vacancies play in the mechanism of NO 2 adsorption in Sb 2 Te 2 Se. • Significant enhancement of resistance response to NO 2 adsorption in Sb 2 Te 2 Se. • Clarification of the mechanism of NO 2 adsorption in Sb 2 Te 2 Se. • Confirmation of the presence of vacancies using Ultraviolet Photoelectron Spectroscopy. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper shows that there is superlinear scaling of vacancies with employment size. That is, there are disproportionally more vacancies relative to employment in urban areas, not just for overall employment, but also for occupational and educational classes. Hence vacancies are more strongly concentrated than the jobs to which they refer. Moreover, we find that, compared to all employment, the concentration of labour demand increases with required skill levels. We show that the stronger growth of jobs in cities is unable to explain this finding and propose an alternative explanation based on vacancy chains in spatially related labour markets. The results suggest that on-the-job searchers have better possibilities in cities to improve their position. This helps explain the higher mobility of especially younger workers in cities and the superior quality of job-worker matches in large labour markets. [ABSTRACT FROM AUTHOR]

Understanding irradiation damage involves a multi-scale and multi-physics approach, integrating data from experiments, simulations and phenomenological models. This paper focuses on its early stages, specifically neutron-induced collision cascades in zirconium, as nuclear-grade zirconium alloys are widely used in fuel assemblies. We have gathered and analysed a significant sample of results from high-fidelity, large-scale molecular dynamics (MD) simulations, employing existing interatomic potentials and the two-temperature model to account for electron–phonon coupling. Our data can be directly applied to higher-scale methods. Furthermore, we carried out a comprehensive statistical analysis of the features associated with the defect production, including the number of defects, their distribution and size of the affected area. As a result, we developed a generative model of collision cascades that is parametric, hierarchical and stochastic, i.e. it takes into account a statistical nature of the phenomenon, is interpretable and shareable. This model has been developed with three primary objectives: to provide a sufficient descriptor of a cascade, to interpolate data obtained from high-fidelity simulations, and to demonstrate that the statistical model can produce representative distributions of primary irradiation defects. The results can be used to generate synthetic inputs for models at longer length and time scales, to provide fast approximations that take into account the morphology of introduced defects, and in general to serve as a powerful analytical tool. [ABSTRACT FROM AUTHOR]

In the presented work, the mechanism of evolution of defects in the crystalline structure after irradiation with 1500 kGy and 3000 kGy absorption dose at room temperature in a 60Co gamma source was studied, using 43 nm sized ZrB 2 crystals. The crystals were characterized by a purity of 99.9%, a powder density of 0.23 g/cm3, a specific surface area of 80 to 120 m2/g, and a hexagonal P6/mmm spatial structure. The dose rate applied was 6.05 Gy/s, with 1.17 and 1.37 MeV energy lines. The effect of particles resulting from the decay of 22Naradioactive isotope β+ with an activity of 10.5 μCi, as well as gamma quanta with an energy of 1.27 MeV, on the core and valence electrons and vacancies in the crystal structure was studied using Positron Annihilation Lifetime Spectroscopy (PALS) and Doppler broadening analysis methods. Additionally, the changes in the S and W parameters, which characterize the distribution of defects within the volume of the ZrB 2 crystal, were studied using the Doppler broadening method. For unannealed material, the positron lifetime τ 1 component varied between 174±2 ps and 181±1 ps. After annealing, the positron lifetime component τ 2 was decreased from 290±3 ps to 226±3 ps, and the intensity component I 2 increased from 17.49% to 40% depending on the radiation dose. The calculated values of the positron lifetime τ for one boron vacancy from ABINIT and MIKA packages were found to be 172 ps and 145 ps, respectively. The material was observed to satisfy the necessary functional conditions at gamma doses not exceeding 3000 kGy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of 5% Ni/SBA-15 with varying contents of CeLa10Cu promoter. • CeLa10Cu promoter enhanced the reducibility and basicity of the catalyst. • 29Si NMR revealed interactions between promoter & support via Ce–O–Si bond. • Raman analysis indicated the enhancement in Ov sites with distinct promoter loading. • CeLa10Cu with 30% content improve stability and resistance to coke formation. This work reports on the catalytic performance of 5 wt% Ni/SBA-15 catalysts promoted with different contents of CeLa10Cu metal-oxide (X = 0%, 10%, 20%, 30%, 40%) towards dry reforming of methane (DRM). The high surface area of SBA-15 allows the confinement of the Ni in its channels and improved its dispersion. The specific surface area of catalysts was found to be in the 182–307 m2/g range. Structural analysis (X-ray diffraction and Raman) of the catalysts showed that ceria-related cubic fluorite phase is only observed at the onset of 20% CeLa10Cu content and higher. Additionally, the Raman studies alongside with 29Si solid state NMR demonstrated the promoter-support interactions through the formation of Ce–O–Si bond (Raman bands at 806 cm−1 and 1065 cm−1). The addition of CeLa10Cu promoter improved the reducibility and basicity of the catalyst, which was reflected in the time-on-stream (stability) tests performed on the reference catalyst (5% Ni/SBA-15) as well as on the 5% Ni/ 30% CeLa10Cu-SBA-15 (i.e. the best performing catalyst of this study). The latter catalyst demonstrated superior coke resistance in the long test runs (100 h). HR-TEM and XPS studies confirmed the formation of NiCu bimetallic alloy where Ni and Cu originating from the active metal and support, respectively; the latter affected the electronic structure and stabilized the catalyst during DRM reaction severe conditions. The CeLa10Cu promotion decreased carbon was formation (TGA analysis). The TGA analysis and Raman spectra of the spent catalysts showed that the 30% CeLa10Cu promotion exhibited the least carbon formation and of amorphous nature during the 100 h DRM. The low angle XRD showed some deterioration in the SBA-15 structure after 100 h DRM, whereas the SBA-15 structure was maintained after 12 h DRM. [ABSTRACT FROM AUTHOR]

• The electrochemical and photochemical NRR mechanism is illustrated deeply and comprehensively. • The research progress of metal-based and nonmetallic NRR catalysts are extensively reviewed. • Interaction and synergistic effects of components in NRR heterojunction catalysts are demonstrated. • Advanced improvement methods of NRR catalysts are summarized. As zero-carbon artificial ammonia synthesis technologies for nitrogen fixation, eNRR (electrocatalytic nitrogen reduction reaction) and pNRR (photocatalytic nitrogen reduction reaction) are receiving more and more attention, in which NRR catalysts play a crucial role with significant potential. Herein, The NRR mechanism including nitrogen adsorption, activation, electron migration, and hydrogenation, eNRR & pNRR experiment system, and the basic properties, structure-performance relationship and advanced improvement design of NRR catalysts are reviewed. Metal-based catalysts including Fe, Mo, Bi, Ti, Ru, Au, Ag, Ce, Zn, Sn and so on, have an advantage in nitrogen adsorption, nitrogen activation and ammonia selectivity. In addition to being catalyst support, non-metallic materials can also have certain NRR activity, such as g-C 3 N 4 and graphene, especially with vacancy design and modification. Besides, the photoelectric and catalytic performance can be further improved by synthesize composite catalysts to produce heterojunction structure. This review aims to assist academia to understand the research progress of NRR technology and catalyst and provide ideas for innovating more promising and high-performance NRR catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phonon properties of pristine, V N 1 + and V N 3 + structures for AlN and GaN calculated. • Discontinuity, splitting, in-gap state, blurry branches appear in phonon bands of. V N q • V N 3 + exhibit larger disturbances in phonon bands/density of states than. V N 1 + • Blueshifts of IR modes appear nearly in all V N q cases. Understanding the effects of defects on the phonon-related properties of III-nitride semiconductors is important for device applications. However, the effect of the charge-state difference on the phonon-related properties of defects has not been studied. This study calculated the phonon bands of AlN and GaN for pristine crystals and crystals with +1 or +3 nitrogen vacancies (V N 1 + or V N 3 + ). Our results revealed distinct differences in the phonon bands, density of states (DOS), and infrared (IR) spectra between pristine and defective crystals, particularly between V N 1 + and V N 3 + . The V N 3 + exhibited a larger disturbance in the phonon bands than V N 1 + . The V N 3 + exhibited more peaks and larger peak intensities in the DOS than V N 1 + . The IR spectrum intensity of A 1 (TO) was larger than that of E 1 (TO) in the V N 3 + , which was different from the pristine and V N 1 + cases. In the IR spectrum of V N 3 + in GaN, a small peak appeared to represent a defect. These results imply that the effects of vacancies on the phonon-related properties depend not only on the concentration but also on the charge state. This study can serve as a guide for future in-depth research on the effect of defects on thermal properties. [ABSTRACT FROM AUTHOR]

Low-energy nuclear reactions are known to be extremely dependent on the local crystal structure and crystal defects of the deuterated samples. This has a strong influence on both hydrogen diffusion and the effective electron mass. The latter determines the strength of the local electron-screening effect and can change the deuteron–deuteron reaction rates at very low energies by many orders of magnitude. In the present study, zirconium samples were exposed to various conditions and energies of deuteron beams using the unique accelerator system with ultra-high vacuum, installed in the eLBRUS laboratory at the University of Szczecin. Irradiated and virgin samples were investigated by means of the X-ray diffraction (XRD) and positron annihilation spectroscopy (PAS). While the first method delivers information about changes of crystal lattice parameters and possible production of hydrides accompanying the formation of dislocations that are produced during irradiation of the samples, the second one can determine the depth distribution of crystal defects, being especially sensitive to vacancies. The studied Zr samples were also implanted by carbon and oxygen ions in order to simulate the real situation taking place in nuclear reaction experiments and to investigate their influence on the kinetic of produced vacancies. The observed enhancement of the electron-screening effect in the deuteron fusion reaction at very low energies could be explained by formation of a high number of vacancies during the deuteron irradiation of samples. Possible carbon and oxygen impurities can affect this process in various ways by changing the depth distribution of vacancies and their diffusion, but they play only a minor role in the strength of the electron-screening effect.

Digital skills play an important role in the digital economy. In many ways, the presence and level of digital skills in the country’s population depends on their demand in the labor market. Despite significant differentiation in the digital economy development in Russian regions, regional differences in the demand for digital skills have not yet been studied. The aim of the study is to determine the main trends in the dynamics of demand for digital skills in Russian regions based on the analysis of employers’ requirements indicated in vacancies. To conduct the analysis, we used vacancies posted by Russian employers on the Unified Digital Platform “Work in Russia” in 2018–2022. The data on the demand for digital skills were obtained on the basis of automated processing of employers’ requirements specified in vacancies. The analysis of the dynamics of demand in the regional context was carried out by three groups of digital skills including basic, advanced and professional. The results of the analysis indicate that there is a slight decrease in the differentiation of Russian regions in the demand for digital skills, but at the same time it remains very significant. The most significant differentiation was found for advanced digital skills, while the smallest was found for basic ones. We also found that in some regions with the beginning of the Covid-19 pandemic the requirements for digital skills have increased significantly. In our opinion, this is due to the varying degree of severity of the restrictive measures taken in the regions of Russia. The novelty of the obtained results is that, in contrast to previous studies on the demand for digital skills, this paper focuses on regional differences. The practical significance of the obtained results is that data on the dynamics and level of demand for digital skills in individual regions can be used to determine priority regions in which appropriate educational and professional development programs can be implemented. Based on the obtained results, in our opinion, a more detailed investigation of the period of the coronavirus pandemic in order to study the impact of crisis phenomena on the labor market is a promising direction for further research.

Abstract The traditional methods of introducing defects into alloy catalysts, such as dealloying, quenching, and doping, usually require complicated processes, rendering less controllability to the products and performances. Herein, a simple fabrication method for vacancy‐rich IrCo alloy nanoparticles supported on N‐doped carbon sheets (denoted as D‐IrCo/NC) is applied by post‐annealing the single atom (Ir and Co) dispersed precursors. The mobile single atoms and the coalescences of metallic clusters are directly observed via in situ transmission electron microscopy. Compared to the alloy catalysts obtained by direct calcination or other traditional methods, the D‐IrCo4.9/NC catalyst is enriched with vacancy defects and only demands an overpotential of 14 mV at j = 10 mA/cm2 for HER. Density functional theory (DFT) calculations reveal that the under‐coordinated Ir sites possess the lowest hydrogen adsorption energy. This novel preparation method is universal, and this work also provides a facile strategy to fabricate highly defective alloy catalysts evolved from single atom precursors.

This investigation highlights the significant influences of alkaline earth ion substitution for Gd on the structure, vacancy defects, magnetic and dielectric properties in GdMnO 3 (GMO) ceramics synthesized using the solid-state reaction method. The structure measurements indicate that all of the Gd 0.90 A 0.10 MnO 3 (A = Ca, Sr, Ba) samples show a single phase structure, and the introduction of A 2+ ion induces structure distortion. A 2+ ions substitution increases the Mn4+ ion concentration in GMOs, but has no significant effect on the oxygen vacancy concentration. All samples with irregular grain shapes have dense microstructures, and A 2+ ion substitution inhibits grain growth. Positron annihilation experimental results indicate that A 2+ ion substitution can increase the vacancy size and concentration, while the vacancy concentration increases first and then decreases with increasing A 2+ ion radius. The evolution of the temperature- and magnetic field-dependent magnetization curves shows that A 2+ ion substitution could obviously affect the magnetic state of GMOs, and improve the magnetic transition temperature and magnetization of Gd 0.90 A 0.10 MnO 3. The dielectric measurements reveal that the A 2+ ion substituted samples exhibit giant dielectric constant characteristics over a broad frequency range. It is found that the enhanced magnetization of Gd 0.90 A 0.10 MnO 3 has a close relationship with the vacancy concentration, and the giant dielectric constant behaviors in Gd 0.90 A 0.10 MnO 3 ceramics can be associated with the mixed-valent structure of Mn3+/Mn4+. [ABSTRACT FROM AUTHOR]

It is commonly believed that the spontaneous p‐doping in Sn‐based perovskites is caused by Sn vacancies. By performing rigorous first‐principles calculations for a prototypical Sn‐based perovskite CsSnI3, we reveal that, in fact, the defects dominating p‐doping are Cs vacancies. The reason that adding extra Sn2+ could reduce p‐doping is that Cs and Sn present the same changing trend in terms of chemical potentials, and thus inhibiting the formation of Sn vacancies will also limit the formation of Cs vacancies. Moreover, we show that I vacancies are the dominant nonradiative recombination centers, and can result in sizable nonradiative losses, which explains why the experimentally measured carrier lifetime is only a few nanoseconds even if p‐doping is suppressed. This work provides new insights into the origins of p‐doping and nonradiative recombination in CsSnI3, and suggests that minimizing the formation of Cs and I vacancies is critical to realizing the best device performance. [ABSTRACT FROM AUTHOR]

It is commonly believed that the spontaneous p‐doping in Sn‐based perovskites is caused by Sn vacancies. By performing rigorous first‐principles calculations for a prototypical Sn‐based perovskite CsSnI3, we reveal that, in fact, the defects dominating p‐doping are Cs vacancies. The reason that adding extra Sn2+ could reduce p‐doping is that Cs and Sn present the same changing trend in terms of chemical potentials, and thus inhibiting the formation of Sn vacancies will also limit the formation of Cs vacancies. Moreover, we show that I vacancies are the dominant nonradiative recombination centers, and can result in sizable nonradiative losses, which explains why the experimentally measured carrier lifetime is only a few nanoseconds even if p‐doping is suppressed. This work provides new insights into the origins of p‐doping and nonradiative recombination in CsSnI3, and suggests that minimizing the formation of Cs and I vacancies is critical to realizing the best device performance. [ABSTRACT FROM AUTHOR]

It is commonly believed that the spontaneous p‐doping in Sn‐based perovskites is caused by Sn vacancies. By performing rigorous first‐principles calculations for a prototypical Sn‐based perovskite CsSnI3, we reveal that, in fact, the defects dominating p‐doping are Cs vacancies. The reason that adding extra Sn2+ could reduce p‐doping is that Cs and Sn present the same changing trend in terms of chemical potentials, and thus inhibiting the formation of Sn vacancies will also limit the formation of Cs vacancies. Moreover, we show that I vacancies are the dominant nonradiative recombination centers, and can result in sizable nonradiative losses, which explains why the experimentally measured carrier lifetime is only a few nanoseconds even if p‐doping is suppressed. This work provides new insights into the origins of p‐doping and nonradiative recombination in CsSnI3, and suggests that minimizing the formation of Cs and I vacancies is critical to realizing the best device performance. [ABSTRACT FROM AUTHOR]

It is commonly believed that the spontaneous p‐doping in Sn‐based perovskites is caused by Sn vacancies. By performing rigorous first‐principles calculations for a prototypical Sn‐based perovskite CsSnI3, we reveal that, in fact, the defects dominating p‐doping are Cs vacancies. The reason that adding extra Sn2+ could reduce p‐doping is that Cs and Sn present the same changing trend in terms of chemical potentials, and thus inhibiting the formation of Sn vacancies will also limit the formation of Cs vacancies. Moreover, we show that I vacancies are the dominant nonradiative recombination centers, and can result in sizable nonradiative losses, which explains why the experimentally measured carrier lifetime is only a few nanoseconds even if p‐doping is suppressed. This work provides new insights into the origins of p‐doping and nonradiative recombination in CsSnI3, and suggests that minimizing the formation of Cs and I vacancies is critical to realizing the best device performance. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) diffusion in gallium nitride (GaN) is assessed using various Mg dosages and annealing durations at 1300 °C under nitrogen at 500 MPa. Low Mg dosages of 3 × 1013 cm−2 result in diffusion based on Fick's law and a diffusion coefficient of 1.36 × 10−14 cm2 s−1. Ambient hydrogen atoms are also introduced into the specimens during annealing. Hydrogen has a larger diffusion coefficient than Mg but the hydrogen concentration is limited by the surface Mg concentration. After hydrogen atoms reach the Mg diffusion front, they enhance Mg diffusion by forming the Mg–hydrogen complexes. The more rapid Mg diffusion at higher Mg dosages above 1014 cm−2 can be explained by diffusive species involving vacancies and hydrogen. [ABSTRACT FROM AUTHOR]

Defect engineering has been considered as a feasible approach to improve the photocatalytic activity in nitrogen fixation. However, as the main determinants of photocatalytic properties, the type of vacancy and controllable preparation methods remain elusive. Herein, a controllable method for defect fabrication on BiOBr is achieved by ultraviolet (UV) light illumination. With extending the UV light illumination time, the type of defects is switched from oxygen vacancies to triple‐vacancy associates (VBi‴VO••VBi‴). Notably, VBi‴VO••VBi‴ is much more stable compared with oxygen vacancies on the surfaces of BiOBr, resulting in higher photocatalytic activity in nitrogen fixation. The reaction mechanism of photocatalytic reduction of N2 to ammonia in different defects‐modified BiOBr is also proposed along with the testing results. Herein, a controllable method to fabricate vacancies on BiOBr induced by UV light is provided, and the reaction pathways of photocatalytic fixation of N2 on different defects‐modified BiOBr are demonstrated. [ABSTRACT FROM AUTHOR]

Herein, the annealing behaviors of defects in ion‐implanted GaN are studied by positron annihilation, cathodoluminescence, scanning transmission electron microscopy, and atom probe tomography. Si or Mg ions are implanted into GaN to obtain 300 nm deep box profiles of the impurities. The samples are annealed up to 1480 °C under a N2 pressure of 1 GPa. For as‐implanted GaN, the major defect species is identified as Ga‐vacancy‐type defects. After annealing above 1000 °C, vacancy clusters are introduced, and they remain even after 1480 °C annealing. For Mg‐implanted GaN with the Mg concentration ([Mg]) ≤ 1018 cm−3, no large change in the depth distribution of Mg is observed before and after annealing at 1400 °C. For the sample with [Mg] = 1019 cm−3, however, Mg diffuses into the bulk, which is attributed to the over‐doping of Mg and their vacancy‐assisted diffusion. The Mg diffusion is suppressed, and the donor–acceptor pair emission is enhanced by sequential N‐implantation, which is attributed to the reaction between Mg and vacancies under a N‐rich condition. For the samples annealed at 1480 °C, an accumulation of Mg around dislocation loops and Mg clustering are enhanced by the N‐implantation [ABSTRACT FROM AUTHOR]

Lanthanum (La) doping is considered as a promising route to overcome reliability issues of switchable ferroelectric HfO2‐based devices. This study links the local chemistry at the La lattice sites with local and collective electronic properties of the La:HfO2 matrix using hard X‐ray photoelectron spectroscopy. The satellite structure of the La 3d core level, the plasmonic excitation energies, and core‐level rigid binding energy shifts are investigated for La:HfO2 samples with a wide range of La doping, ranging from 3.5% to 33%, i.e., from the doping to dilution level. The emerging chemical phases and electronic properties are discussed as a function of La content. From the evolution of the plasmon excitation energies and rigid binding energy shifts, it is concluded that electronic charge compensation by oxygen vacancies occurs for increasing La content. [ABSTRACT FROM AUTHOR]

The crystal structure of the NbO compound can be described as a vacancy-ordered derivative of the NaCl (B1) structure type with a concentration of structural vacancies of 25 at.% simultaneously in two sublattices. It was previously supposed that as the pressure increased, the vacancy-free NbO crystal with the B1 structure stabilized. In this work, effects of the pressure and the concentration of vacancies on the NbO structure are investigated by density functional theory methods. A new vacancy-free NbO phase with the rhombohedral crystal structure is found, its thermodynamic stability is evaluated, and the electronic structure is analyzed. It is demonstrated that with an increase in the pressure, rhombohedral NbO must be enthalpically stabilized rather than the vacancy-free NbO phase with the B1 structure. [ABSTRACT FROM AUTHOR]

Designing the core-shell structure and controlling defect engineering are desirable for improving the performance and stability of semiconductor photocatalysts. Herein, CdS nanorods covered with ultra-thin ZnIn 2 S 4 nanosheets, named as CdS@ZnIn 2 S 4 -S V (CdS@ZIS-S V), was synthesized through the strategy of constructing core-shell structure and regulating vacancies. The core-shell structure can confine Cd2+ and S2− locally around CdS instead of rapidly diffusing into the solution, thereby inhibiting photo-corrosion. The abundant S vacancies can capture photogenerated electrons and promote the separation of electron-hole pairs, thereby preventing the oxidation of S2− by the holes. In addition, Z-Scheme heterojunction structure helps the effective separation of electron-hole pairs. Notably, the hydrogen production rate of CdS@ZIS-S V reached 18.06 mmol g−1 h−1, which was 16.9 and 19.6 times than pristine CdS (1.16 mmol g−1 h−1) and ZIS (0.92 mmol g−1 h−1), respectively. Photoelectric Characterization (PEC), Scanning Kelvin Probe (SKP), UV–vis diffuse reflectance spectra (UV–Vis DRS), Finite-Difference Time-Domain (FDTD) explain the electron transfer mechanism and the reason for the enhanced photocatalytic activity. This work has guiding significance for the preparation of photo-catalysts with high activity and inhibiting photo-corrosion by adjusting S vacancies. CdS nanorods covered with ultra-thin ZnIn 2 S 4 nanosheets has been synthesized through the strategy of constructing core-shell structure and regulating vacancies to form the heterojunction of CdS@ZIS with S Vacancies. CdS@ZIS-S V has high photocatalytic activity and excellent stability. UV–Vis, SKP, FDTD simulation and PEC explored the photocatalytic mechanism. [Display omitted] • Synthesis of CdS@ZIS core-shell structures containing S vacancies by hydrothermal method. • The core-shell structure and S vacancies can inhibit the photocorrosion of CdS and ZIS, respectively. • The charge carrier transfer between CdS and ZIS follows the Z-scheme route. • CdS@ZIS-Sv exhibits excellent photocatalytic activity and cycling stability. [ABSTRACT FROM AUTHOR]

Lanthanum (La) doping is considered as a promising route to overcome reliability issues of switchable ferroelectric HfO2‐based devices. This study links the local chemistry at the La lattice sites with local and collective electronic properties of the La:HfO2 matrix using hard X‐ray photoelectron spectroscopy. The satellite structure of the La 3d core level, the plasmonic excitation energies, and core‐level rigid binding energy shifts are investigated for La:HfO2 samples with a wide range of La doping, ranging from 3.5% to 33%, i.e., from the doping to dilution level. The emerging chemical phases and electronic properties are discussed as a function of La content. From the evolution of the plasmon excitation energies and rigid binding energy shifts, it is concluded that electronic charge compensation by oxygen vacancies occurs for increasing La content. [ABSTRACT FROM AUTHOR]

The conditions of vacancies'-concentration ordered-distribution formation inside the two-dimensional rectangular plate are considered. Corresponding equation for the stationary case is analysed. The interaction between vacancies is described by the function S(x, y); in the work, evident expression for S(x, y) is found. As shown, for the constant temperature on a surface plate, self-organization (ordered-distribution formation) can take place only inside the very little plate. It is possible the onset of complicated dependence of vacancies' density on the co-ordinates within the big plate, if there is a functional dependence of temperature on the plate co-ordinates. [ABSTRACT FROM AUTHOR]

High‐voltage manganese‐based materials are considered as promising cathode materials for aqueous zinc‐ion batteries (AZIBs). Herein, oxygen vacancy‐rich K0.5Mn2O4 sheets were anchored uniformly onto honeycomb‐like interconnected carbon nanoflakes (CNF@K0.5Mn2O4) for AZIB cathode applications. In the composite, the CNFs provided excellent intergranular electron transport capability, while the oxygen vacancies enhanced the electron transport efficiency inside crystals, and the embedded K ions expanded the interlayer spacing and stabilized the layered crystal structure. A reversible specific capacity of 241 mAh g−1 could be maintained by the composite at 0.5 A g−1 for 400 cycles. A combination of ex‐situ analytical methods and density functional theory calculations was carried out to elucidate the electrochemical mechanism of reversible zinc storage. In addition, flexible quasi‐solid‐state batteries of Zn//CNF@K0.5Mn2O4 were constructed by substituting the traditional aqueous electrolyte for a quasi‐solid‐state gel electrolyte, which worked efficiently and exhibited high bending durability. [ABSTRACT FROM AUTHOR]

Hydrogen is an energy carrier that can be a sustainable solution for alternative energy with zero greenhouse gas emissions. Hydrogen storage is a key point for hydrogen energy. Metals provide an access for safe, controlled and reversible hydrogen storage and release. Magnesium, due to its outstanding hydrogen storage capacity, high natural abundance, low cost and non-toxicity is one of the most attractive materials for hydrogen storage. The economic efficiency of Mg as a hydrogen accumulator is limited by its sluggish hydrogen sorption kinetics and high stability of its hydride MgH2. Many attempts have been made to overcome these shortcomings. On a microscopic level, hydrogen absorption by metal is a complex multistep process that is impossible to survey experimentally. Theoretical studies help to elucidate this process and focus experimental efforts on the design of new effective Mg-based materials for hydrogen storage. This review reports on the results obtained within a density functional theory approach to studying hydrogen interactions with magnesium surfaces, diffusion on Mg surfaces, into and in bulk Mg, as well as hydrogen induced phase transformations in MgHx and hydrogen desorption from MgH2 surfaces. [ABSTRACT FROM AUTHOR]

Monte Carlo simulations are used to investigate the main effects related to the hysteresis loops of magnetite and maghemite spinel nanoparticles. In particular, the influence of the finite size of the nanoparticles, the measurement temperature, the roughness of the surface, and the anisotropy are examined. The classical spin model with Heisenberg-type interactions was used with the dominant term of super-exchange interaction in spinel structure. The simulated hysteresis loops are carried out on nanoparticles with perfect or disordered surface and dilution of octahedral sublattice. The simulated hysteresis loops change significantly due to the competition between magnetic anisotropy mainly at the surface of the nanoparticle and the presence of super-exchange interaction. We show the existence of a net magnetization at the surface which is at the origin for the variation of the hysteresis loops shape. [ABSTRACT FROM AUTHOR]

Detection of defective crystal structures can help in refute such defective structures to decrease industrial defects. In our research, we are concerned with Silicon nitride crystals. There are four types of crystal structure classes, namely no-defect structures, pristine crystal structures, defective random displacement crystal structures, and defective 25% vacancies crystal structures. This paper proposes a deep learning model to detect the four types of crystal structures with high accuracy and precision. The proposed model consists of both classification and regression models with a new loss function definition. After training both models, the features extracted are fused and utilized as an input to a perceptron classifier to identify the four types of crystal structures. A novel dense neural network (DNN) is proposed with a multitasking tactic. The developed multitask tactic is validated using a dataset of 16,000 crystal structures, with 30% highly defective crystals. Crystal structure images are captured under cobalt blue light. The multitask DNN model achieves an accuracy and precision of 97% and 96% respectively. Also, the average area under the curve (AUC) is 0.96 on average, which outperforms existing detection methods for crystal structures. The experiments depict the computational time comparison of a single training epoch of our model versus state-of-the-art models. the training computational time is performed using crystal structures diffraction image database of twelve image batches. It can be realized that the prediction computational time of our multitasking model is the least time of 21 s. [ABSTRACT FROM AUTHOR]

Recently, layered double hydroxides (LDH) have shown great potential in photoreduction of CO 2 owing to its flexible structural adjustability. In this study, the mild acidic property of tannic acid (TA) is exploited to etch the bimetal LDH to create abundant vacancies to gain the coordination unsaturated active centers. Based on the different chelating abilities of TA to various metal ions, the active metals are remained by selective chelation while the inert metals are removed during the etching process of bimetal LDH. Furthermore, selective chelating with metal ions not only increases the percentage of highly active metals but also compensates for the structural damage caused by the etch, which achieves a scalpel-like selective construction of vacancies. The NiAl-LDH etched and functionalized by TA for 3 h exhibits superior photo-reduction of CO 2 performance without co-catalysts and photo-sensitizers, which is 14 times that of the pristine NiAl-LDH. The fact that many bimetal LDHs can be functionalized by TA and exhibit significantly improved photocatalytic efficiency is confirmed, suggesting this strategy is generalized to functionalize double- or multi-metal LDH. The method provided in this work opens the door for polyphenol-functionalized LDHs to enhance their ability for light-driven chemical transformations., (© 2024 Wiley‐VCH GmbH.)

In this study, a 304 stainless steel (304 SS)/20 carbon steel (20 CS) bimetal was prepared by vacuum diffusion bonding, with 20 CS as the substrate and 304 SS as the cladding layer, and the interfacial microstructure and bonding strength before and after solution treatment were studied. The 304 SS and The 20 CS formed a strong metallurgical bond after being held at 1380 °C for 60 min without defects such as unbonded regions. Diffusion of Cr and Ni atoms from the 304 SS to the 20 CS occurred, and the C atoms diffused from the 20 CS to the 304 SS, forming a carburized region. A pearlitic region with an average width of approximately 20 μm was formed on the 20 CS side. After solution treatment, austenitization was formed in the carburized region, which was accompanied by the formation of twin crystals. The interfacial bonding strength of the bimetal was measured to be 485 MPa, which increased to 547 MPa after the solution treatment.

The directed electron transport channel design in semiconductors, which could promote charge utilization, is attractive but rarely reported. Hierarchical branched titanium dioxide (HB-TiO 2 ), possessing a charge cascade transfer channel, was constructed by assembling titanium-defected TiO 2 nanobranches on oxygen-defected TiO 2 nanobelts. The interfacial Ti/O vacancies have been detected by X-ray photoelectron and electron paramagnetic resonance spectroscopies, and the vacancies act as the "bridge" of photogenerated carrier transport. This structure maintained high photoactivity in H 2 production in different mass fractions of NaCl solutions. The photocurrent density of the HB-TiO 2 photoanode in natural seawater is 3.9, 2.1, and 2.6 times that of oxygen-defected TiO 2 nanobelts, titanium-defected TiO 2 nanobranches, and their mixture, respectively. Besides, the charge transport mechanism from the inner lattice to the TiO 2 surface is proposed.

The article presents the results of an analysis of the demand for labor of personnel management specialists in Moscow according to the state as of July 2021. It provides a brief overview of the leading world and Russian employment sites. The correctness of using the HeadHunter website (hh.ru) for analysing the demand for HR specialists in the Moscow labor market has been substantiated. Based on the results of a preliminary analysis of positions offered to HR specialists in Moscow, a sample of 250 vacancies has been formed, on which the requirements of employers to applicants have been assessed. The analysis has been carried out for three large groups: for managers (directors) for personnel, chief (leading) specialists and specialists (assistants). A Box Plot diagram has been constructed and analysed based on the salary proposals.

Abstract Even though the recession in Switzerland triggered by COVID-19 ultimately remained without consequences for the apprenticeship market, significantly fewer apprenticeship contracts had been signed in the months of the first shutdown in 2020 than in the same months of the previous year. Using daily search queries on the national administrative platform for apprenticeship vacancies from February 2020 until April 2021 as a proxy for the supply of potential apprentices, we find a temporal pattern that coincides perfectly with the development of signed apprenticeship contracts. Furthermore, the analyses show that the initially very strong relationship between the intensity of the politically imposed restrictions to fight the COVID-19 pandemic and the daily search queries diminished over time, leading to a search intensity in March 2021 that was back at pre-pandemic level.