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We report on a laboratory experiment testing the predictions of the Diamond–Mortensen–Pissarides (DMP) search-and-matching model, which is a workhorse, decentralized model of unemployment and the labor market. We focus on the job vacancy posting problem that firms face in the DMP model. We explore the model's comparative statics predictions concerning variations in the separation rate, the vacancy posting cost, and the firm's surplus earned per employee. Across all treatments, we find strong evidence for an inverse relationship between vacancies and unemployment, consistent with the Beveridge curve. We also find that the results of our various comparative statics exercises are in-line with the predictions of the theory.

Composites consisting of two nano-or molecular-scale components tend to exhibit newer properties or characterizations compared to the matrix material. However, they are extremely limited in thermoelectricity due to the difficulty of achieving an extremely homogeneous distribution of the material on such a small scale. In this paper, we successfully prepared a series of composite thermoelectric materials of Sr 0.9 La 0.1 Ti 0.85 Nb 0.15 O 3 /carbon nanotubes (CNTs, with contents of 0.5, 1.5, 2.5, and 5.0 wt%). Highly homogeneous dispersion of CNTs was observed in the strontium titanate oxide (SrTiO 3) matrix prepared via high-temperature and high-pressure (HPHT) synthesis due to the interaction between SrTiO 3 and multi-walled CNTs. The experimental results showed that CNTs were uniformly dispersed in the composite powders synthesized using the HPHT method. Meanwhile, the electrical conductivity increased linearly with the increase in the CNTs content. The power factor reached 684 μWm−1K−2 at 973K with 2.5 wt% CNTs composite concentration. This considerable enhancement is attributed to the increase in the charge carrier concentration as well as the higher electron mobility. In addition, the lattice thermal conductivity was suppressed due to enhanced Umklapp scattering. This ultimately leads to a thermoelectric figure of merit, zT , of 0.33 at 973 K. This work opens a new window on the thermoelectric properties of nanocomposite SrTiO 3 -based thermoelectric materials. [ABSTRACT FROM AUTHOR]

Performance breakthrough of energy‐storage electrodes under commercial‐level mass loading (≥10 mg cm−2) are highly pursued but restricted by sluggish mass/charge transfer rates and kinetically unfavorable reaction sites. In response, through electrochemical microenvironment reconstitution, these limitations are broken by engineering synergy between vacancies and oxyanions in the active matrix (Rec‐NiCoExch), which showcases a record‐level areal capacitance of 10.9 C cm−2 with a high mass loading of 20 mg cm−2 and a retention of 72% at 100‐fold current density. Such a design further endows the hybrid supercapacitor with an areal capacity of 20.9 C cm−2 and an energy density of 4.6 mWh cm−2, outperforming most of the benchmark results. Theoretical calculation reveals that in situ evolved oxyanions not only act as the effective adsorption sites but also secure the oxygen vacancies, enabling the potential synergy toward improved electronic conductivity and enhanced reactivity of Ni sites. As a proof‐of‐concept, the as‐assembled quasi‐solid‐state micro‐supercapacitor deliveries an ultrahigh energy density of 111.5 µWh cm−2 and presents great potential in intermittent energy storage by the solar panel‐supercapacitor‐LED system. This work offers insights for constructing commercial‐level energy‐storage electrodes by mastering surface/interface engineering for practical applications. [ABSTRACT FROM AUTHOR]

The vacancies and nitrogen dopants significantly alter the interfacial bonding and electrical properties at the graphene/metal interface. The graphene/copper system, characterized by coherent and immiscible interfaces, serves as a suitable benchmark to elucidate the intrinsic interactions between carbon and metal atoms. Herein, the individual effects of vacancies and nitrogen dopants, as well as their combined effects, are systematically investigated. The bonding energies show that the interfacial bonding is the strongest at the monovacancy (MV) graphene/copper interface, indicating that the introduction of nitrogen in defective graphene/copper interfaces weakens the interfacial bonding. Furthermore, the band structures indicate that both vacancies and nitrogen dopants contribute to the formation of a bandgap. Among them, both MV and graphitic nitrogen doping significantly enhance interfacial bonding while maintaining relatively intact interfacial and band structures. [ABSTRACT FROM AUTHOR]

The creation of vacancies and/or pores into two‐dimensional materials, like graphene and MXenes, has shown to increase their performance for sustainable applications. However, a simple and affordable method with controlled and tailorable vacancy concentration and/or pores size remains challenging. Herein, a simple and reproducible method is presented for controlled synthesis of Mo1.74CTz MXene with randomly distributed vacancies and pores, obtained from selective etching of both Ga and Cr in the Cr‐alloyed MAX‐phase like precursor Mo1.74Cr0.26Ga2C. Structural and compositional analysis of the 3D alloy show ≈13% Cr on the metal site, homogeneously distributed between different particles and within the atomic structure. After etching, it translates to Mo1.74CTz MXene, exhibiting defect‐rich sheets. Notably, the incorporation of Cr facilitates a shorter etching time with an improved yield compared to Mo2CTz. The Mo1.74CTz MXene displays excellent electrochemical properties, almost doubling the capacitance values (1152 F cm−3 and 297 F g−1 at 2 mV s−1 scan rate), compared to its pristine counterpart Mo2CTz. The presented method and obtained results suggest defect engineering of MXenes through precursor alloying as a pathway that can be generalized to other phases, to further improve their properties for various applications. [ABSTRACT FROM AUTHOR]

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This paper systematically reviews the progress on the HgCdTe (MCT) material deposition via molecular-beam epitaxy (MBE) and previously reported atomistic approaches used to model the MCT epitaxy. The structure design and fabrication of the infrared (IR) detection systems require highly crystalline MCT films. The state-of-the-art of the MBE growth processes of Hg1−xCdxTe films over Si, GaAs, GaSb, and CdZnTe substrates are reported here from an atomistic simulation perspective. The most advanced in-house-developed kinetic Monte Carlo (kMC) technique, coupled with the geometry of the MBE reactor (implemented in the TNL-EpiGrowTM simulator) is exploited to reproduce real-time MBE experiments. The ability to track each atom involved in the adsorption, diffusion, and desorption processes over the lattice provides deeper insights. The ability to map various defects quantitatively and qualitatively during the growth process in a layer-by-layer and island mode helps to provide a proper understanding of their formation. The TNL-EpiGrowTM simulator provides an innovative and cost-effective solution for the epitaxial growth processes associated with MBE, CVD, and MOCVD reactors for most semiconductors. The types of defects, their position over the lattice, layer-by-layer strain, surface roughness, lattice parameters are easily extractable and provide an unmatched solution. However, it is very difficult to realize similar solutions through sophisticated instruments. Si, GaAs, GaSb, and CdZnTe substrates have been used to reproduce the MBE process of Hg1−xCdxTe (x ≈ 0.55). The vacancies and dislocation densities are reported here to characterize the cases of MCT epitaxy on the four different substrates. The growth rates of CdTe and MCT have been benchmarked against the experimental data (Pacuski et al. in Cryst Growth Des 17(6):2987, 2017; Wijewamauriya et al. in Appl Phys Lett 51(24):2025, 1987). The output results revealed that CdZnTe is the most attractive substrate choice but, due to its technological challenges, GaSb can replace it and is the most suitable option for the growth of Hg1−xCdxTe as compared to Si and GaAs substrates under similar conditions. The results reported here also support the experimental findings (Gu et al. in J Cryst Growth 468:216, 2017). The dislocations and vacancies generated in the GaSb substrate are comparable to those in the CdZnTe substrate. [ABSTRACT FROM AUTHOR]

[Display omitted] Nonaqueous Li − O 2 battery (LOB) is considered one of the most promising energy storage system due to its ultrahigh theoretical specific capacity (3500 Wh kg−1). Introducing vacancies in CoMn 2 O 4 catalysts is regarded as an effective strategy to enhance the electrochemical performances of LOB. However, the relation between vacancy types in CoMn 2 O 4 and catalytic performances in the LOB remains ambiguous. Herein, ordered porous CoMn 2 O 4 with oxygen and metal vacancies is obtained via solvothermal reaction followed by temperature-controlled calcination using polystyrene spheres as templates. The increase in treatment temperature reduces the content of oxygen vacancies while increasing that of the metal vacancies. Notably, experimental results and theoretical calculations show that oxygen vacancies in CoMn 2 O 4 have a greater influence than metal vacancies in modulating the LiO 2 adsorption during the reaction processes and reducing the overpotential. CoMn 2 O 4 synthesized at 500 ℃ (CoMnO-500) with higher oxygen vacancies exhibits stronger adsorption onto the LiO 2 , facilitating the formation of film-like Li 2 O 2. Therefore, an LOB with the CoMnO-500 catalyst presents the lowest overpotential of 1.2 V and longest cycle lifespan of 286 cycles at a current density of 200 mA g−1. This study offers insights into the effect of CoMn 2 O 4 vacancies on the formation pathway of Li 2 O 2 discharge products. [ABSTRACT FROM AUTHOR]

AbstractProblem, research strategy, and findingsTakeaway for practiceThough demand for living near urban amenities has grown over the past two decades, retail vacancies continue to plague many urban areas. Are cities overzoning for retail? Can this overzoning explain the proliferation of urban retail vacancies in the past two decades? We first leveraged longitudinal data on retail leases to depict patterns of retail market activity in a sample of seven moderate to large U.S. cities. Second, we used property-level data on land use regulation to investigate whether institutional context, specifically zoning, has played a role in patterns of urban retail vacancy in the past two decades. We drilled down in New York City (NY) and Los Angeles (CA) to compare trends in retail leases with changes in regulated retail land use between 2006 and 2022. We show that in this period retail rents remained flat or declined and that the average retail space did not grow and may have shrunk. Our New York and Los Angeles microdata document that, during roughly this same period, the amount of land zoned for retail increased and that the building square footage zoned for retail grew even more rapidly. Indeed, during the same decades when retail leasing slowed and rents declined, the total amount of land and square footage regulated for retail use increased. Thus, our research indicates that, in addition to market forces, land use decisions have driven the current oversupply of retail space. This also suggests an important role for planning in solving the problem of vacancies.If macroeconomic factors drive the obsolescence of certain commercial uses, local zoning and comprehensive planning should respond accordingly. As cities emerge from the pandemic and adjust to new work–live patterns, planning for the volume and spatial distribution of retail will remain an important task for urban planners and managers. [ABSTRACT FROM AUTHOR]

The magnetic properties of van der Waals materials are profoundly influenced by structural defects. The layered antiferromagnet MnPS3 offers a unique opportunity to explore defect‐related magnetism, as Mn2+ vacancies can be generated by the intercalation of specific guest molecules. However, the effectiveness of this process in atomically thin flakes and the extent of the magnetic tunability remain unclear. Here, it is shown that the magnetic properties of MnPS3 can be tailored through the intercalation of different guest molecules. Notably, the insertion of four alkylammonium ions introduces different populations of Mn2+ vacancies, leading to a transition from the pristine antiferromagnetic state to more complex magnetic textures, including a ferrimagnetic state displaying a magnetic saturation of 1 µB per atom. Moreover, it is shown that the intercalation of few‐nm‐thick flakes also leads to the emergence of a ferrimagnetic response. This in‐flake intercalation, which can be monitored in real time using optical microscopy, can be interrupted before completion, generating lateral heterostructures between pristine and intercalated areas. This approach opens the way to the use of partial intercalation to define regions with distinct magnetic properties within a single flake. [ABSTRACT FROM AUTHOR]

In monolayer transition metal dichalcogenides, defects, such as chalcogen vacancies, play an important role in determining their properties. Herein, monolayer MoSe2 with varying Se vacancy concentrations is successfully prepared by adjusting the amount of the precursors during the chemical vapor deposition synthesis. The Raman and low‐temperature photoluminescence spectra are systematically studied at varying defect concentrations. Furthermore, it is found that Se vacancies introduce in‐gap electronic states, leading to distinct localized exciton emissions, which can be engineered by controlling the concentration of Se vacancies. Density functional theory calculations indicate that the observed variations in localized exciton emission are attributed to the change of defect level with increasing defect concentration. The results provide insights into the influence of varying Se vacancy concentrations on defect‐induced Raman and PL spectroscopy in MoSe2. [ABSTRACT FROM AUTHOR]

In monolayer transition metal dichalcogenides, defects, such as chalcogen vacancies, play an important role in determining their properties. Herein, monolayer MoSe2 with varying Se vacancy concentrations is successfully prepared by adjusting the amount of the precursors during the chemical vapor deposition synthesis. The Raman and low‐temperature photoluminescence spectra are systematically studied at varying defect concentrations. Furthermore, it is found that Se vacancies introduce in‐gap electronic states, leading to distinct localized exciton emissions, which can be engineered by controlling the concentration of Se vacancies. Density functional theory calculations indicate that the observed variations in localized exciton emission are attributed to the change of defect level with increasing defect concentration. The results provide insights into the influence of varying Se vacancy concentrations on defect‐induced Raman and PL spectroscopy in MoSe2. [ABSTRACT FROM AUTHOR]

The novel potassium sulfido cobaltate, K2[Co3S4] is introduced, with 25% vacancies of the cobalt positions within a layered anionic sublattice. The impedance and dielectric investigations indicate a remarkable ionic conductivity of 21.4 mS cm−1 at room temperature, which is in the range of highest ever reported values for potassium‐ions, as well as a high electrical permittivity of 2650 at 1 kHz, respectively. Magnetometry results indicate an antiferromagnetic structure with giant intrinsic exchange bias fields of 0.432 and 0.161 T at 3 and 20 K respectively, potentially induced by a combination of the interfacial effect of combined magnetic anionic and nonmagnetic cationic sublattices, as well as partial spin canting. The stability of the exchange bias behavior is confirmed by a training effect of less than 18% upon 10 hysteresis cycles. The semiconductivity of the material is determined, both experimentally and theoretically, with a bandgap energy of 1.68 eV. The findings render this material as a promising candidate for both, active electrode material in potassium‐ion batteries, and for spintronic applications. [ABSTRACT FROM AUTHOR]

We find that job vacancies in local government appear to be a widespread and significant problem for the public sector affecting a wide range of occupations across wage levels and educational requirements. We offer suggested policy solutions raised by subject matter experts and other reports and analyses on job vacancy challenges in local government.

In this study, the influence of foreign and native point defects in magnesium oxide on the sintering process is examined. We have introduced dopants into magnesium oxide, with cations that share similar sizes but possess varying charges to minimize the direct impact of strain. The selected foreign cations were as follows: (1) Li1+, an acceptor that enhances the concentration of oxygen vacancies; (2) Sc3+, a donor that enhances the concentration of magnesium (metal) vacancies; and (3) Zn2+, an isovalent dopant. The results reveal that oxygen vacancies introduced by lithium doping greatly decrease the sintering temperature of magnesium oxide compared to the magnesium vacancies' effect (scandium doping). Zinc doping was found to increase the surface oxygen vacancies with only a minor effect on the sintering temperature. Enhancing the oxygen vacancy concentration by lithium doping creates an additional mechanism for sintering because the anion sublattice is the backbone of the material, and oxygen ion diffusion is the rate‐limiting step. Scandium doping also has a sintering–promoting effect, yet a minor one. The doping factor analysis is considered and implies that aliovalent dopants do not affect the concentration of the fast‐diffusing species, which are native vacancy associates. [ABSTRACT FROM AUTHOR]

The inefficiency of electrocatalysts for water splitting in neutral media stems from a comprehensive impact of poor intrinsic activity, a limited number of active sites, and inadequate mass transport. Herein, hierarchical ultrathin NiCo2Se4 nanosheets are synthesized by the selenization of NiCo2O4 porous nanoneedles. Theoretical and experimental investigations reveal that the intrinsic hydrogen evolution reaction (HER) activity primarily originate from the NiCo2Se4, whereas the high oxygen evolution reaction (OER) performance is related to the NiCoOOH due to the structural reconstruction. The abundant Se and O vacancies introduced by atomically thin nanostructure modulate the electronic structure of NiCo2Se4 and NiCoOOH, thereby improving the intrinsic HER and OER activities, respectively. COMSOL simulation demonstrate the edges of extended nanosheets from the main body significantly promote the charge aggregation, boosting the reduction and oxidation current during HER/OER process. This charge aggregation effect notably exceeds the tip effect for the nanoneedle, highlighting the unique advantage of the hierarchical nanosheet structure. Benefiting from abundant vacancies and unique nanostructure, the hierarchical ultrathin nanosheet simultaneously improve the thermodynamics and kinetics of the electrocatalyst. The optimized samples display an overpotential of 92 mV for HER and 214 mV for OER at 100 mA cm−2, significantly surpassing the performance of currently reported HER/OER catalysts in neutral media. [ABSTRACT FROM AUTHOR]

Limited by sluggish reaction kinetics, insufficient electrode utilization and severe volume deformation, designing nickel‐based materials with high capacity and rate capability is still a challenge. Herein, a carbon nanotubes threaded NiSe2/Co3Se4 quantum dots embedded in carbon nanospheres with rich Se vacancies both in NiSe2 and Co3Se4 is elaborately designed via MOF template method. The formation mechanism of the Se vacancies is elucidated for the first time, which is ascribed to the release of gas during the decomposition of organic ligand inhibits the ordered arrangement of atoms. The CNT‐V‐NiCoSe possesses many significant superiorities, such as sufficiently exposed active sites, high electrode utilization, favorable charge‐carrier migration, and relaxed structure deformation. Consequently, the CNT‐V‐NiCoSe electrode shows top‐level specific capacity (384 mAh g−1 at 1 A g−1), ultrahigh rate capability (209 mAh g−1 at 150 A g−1) and remarkable cycling durability. The CNT‐V‐NiCoSe//Zn battery achieves maximum energy density of 615.6 Wh kg−1 and maximum power density of 81.7 kW kg−1. Density functional theory calculations elucidate the Se vacancies improve the density of states at Fermi level, facilitates internal charge transfer, and enhances OH− adsorption ability. This study provides guidance for the preparation of high‐performance electrode materials with rich vacancies by template method. [ABSTRACT FROM AUTHOR]

Prussian blue analogs (PBAs) featuring with 3D open framework are recognized as promising cathode candidates for Zinc‐ion batteries (ZIBs). However, challenges such as unsatisfactory active site utilization, low conductivity, and abundant structural vacancies have impeded fulfillment of their potential. In this work, a conductive in‐plane porous MXene is for the first time adopted as a multifunctional host material to enhance cobalt hexacyanoferrate (CoHCF) growth and crystallinity. Particularly, the uniform surface charges on MXene are identified to induce anisotropic and highly crystalline CoHCF, which are critical to alleviating the practical drawbacks associated with the PBAs family. Empowered by the targeted modification, the CoHCF nanotube/MXene composite realizes high surface area and low defectiveness, resulting in an impressive capacity of 197 mAh g−1 at 0.1 A g−1 and capacity retention of 95.3% over 3000 cycles at 2.0 A g−1. X‐ray spectroscopy and density functional theory (DFT) reveal that Co─C bonds in the heterostructure facilitate rapid electron/Zn‐ion transfer, enhancing Zn storage kinetics. To validate practical applicability, pouch cells incorporating Zn|CoHCF/MXene are further examined. This composition strategy, utilizing MXene as a multifunctional template, enhances the surface area, conductivity, and crystallinity of PBAs as cathodes for ZIBs, showcasing the significant potential for large‐scale energy storage applications. [ABSTRACT FROM AUTHOR]

Experimentally it is shown that without any oxygen manipulation for TiO2, a strong room temperature ferromagnetism could be expected only in ultra-thin films, with the ideal thickness below 100 nm. Both bulks and nano-powders of TiO2 are diamagnetic, indicating that the surface and its nano-sublayers play very important roles in tailoring the magnetic properties in this type of compound. To shed a new light on the defect-related magnetism in the typical case of anatase TiO2 surfaces, we have performed a series of quantum-mechanical calculations for TiO2 slabs containing Ti or O vacancies in different distances from the (001) surface. The lowest formation energies were obtained for the Ti vacancies in the first sub-surface layer and the O vacancies within the surface. The computed magnetic states reflect complicated structural relaxations of atoms influenced by both the surface and vacant atomic positions. O atoms cannot contribute much to magnetic moment when Ti vacancies are isolated and far from the surface. Ti vacancies in TiO2 are only metastable. The formation energy of Ti interstitials is lower than for Ti vacancies since high-temperature annealing, especially with a lot of O2 available that would fill up O-related defects, and as a result, eliminate most of Ti vacancies. Lower temperatures, less O2, and shorter exposure times may enable not only partial elimination of Ti vacancies but also can facilitate their diffusion into different states of aggregations. In the ferromagnetic films (i.e. thin films below 100 nm), it looks like that the O atoms are located closer to the Ti vacancies. [ABSTRACT FROM AUTHOR]

Surface structure and relevant oxygen vacancy play an important role in the application of RE2Si2O7 for environmental barrier coatings, in which the oxygen vacancies in RE2Si2O7 may influence their thermal and optical properties. In this work, the structure and thermodynamics of (0 0 1) and (1 1 0) surfaces of RE2Si2O7 (RE = Yb, Lu) are studied via first‐principles calculations to reveal the underlying mechanism of the surface formation and the associated oxygen vacancy behavior. The (1 1 0) surface is preferred energetically, being in good agreement with the experiential results. It is uncovered that the weak chemical bond broken dominates the decrease of the surface energy, together with the contribution from the polyhedral distortion. Furthermore, the [O3Si–O–SiO3] site is found to be the preferred site for oxygen vacancies on (1 1 0) surface. The formation energies of oxygen vacancies on the (1 1 0) surfaces are lower than those in the bulk, suggesting their segregation on the surfaces. These findings provide essential insights into the surface excitation and oxygen vacancy behaviors of RE2Si2O7, which could shield light on the experimental improvement of the thermal, mechanical, and corrosion properties for RE2Si2O7‐based environmental barrier coating materials. [ABSTRACT FROM AUTHOR]

Single‐atom and vacancy‐engineered photocatalysts have shown their remarkable strengths in improving carrier transfer dynamics, yet constructing the integration of single atoms and vacancies as the active site is still challenging. Herein, an icing‐assisted photochemical strategy has been employed to anchor Pd single atoms in Zn vacancies on CdxZn1−xS nanorods to form a Pd–S4 tetrahedron coordination structure, enabling exceptional photocatalytic water splitting performance in the absence of any sacrificial agents. Under visible light irradiation, the H2 evolution rate of Pd/Cd0.1Zn0.9S reaches 608.2 μmol g−1 h−1, which is around 229, 6.7, 6.1, and 2 times to that of ZnS, Cd0.1Zn0.9S, Pd/ZnS, and Pd NPs/Cd0.1Zn0.9S, respectively. Detailed experimental and theoretical analyses confirm that Pd–S hybridized electronic states and Pd single atoms are beneficial for enhancing the charge separation/transfer, accelerating the formation of H* and the release of H2. [ABSTRACT FROM AUTHOR]

The article proposes a method of temperature activation–relaxation of the permittivity for determining the activation energy of defects in ferroelectrics using lead zirconate–titanate Pb(Zr,Ti)O3 samples as an example. This method is based on the analysis of relaxation of the permittivity after thermal annealing and the analysis of the temperature activation of the permittivity of the Pb(Zr,Ti)O3 ferroelectric. The equality of the activation energy corresponding to the process of migration of oxygen vacancies and the thermal energy of the decay of the domain structure was established, which was confirmed by studying the surface of the samples by scanning electron microscopy. When this temperature was reached, the surface of the domain walls was detached from oxygen vacancies, which are pinning centers. This manifested itself in photographs of the microstructure as a change in the ordering of the domains emerging on the surface of the sample, which led to an irreversible decrease in the permittivity of the sample. For the obtained activation energies, the physical process of domain wall motion activation is established, which is determined by their pinning on structural defects (oxygen vacancies). It is assumed that the irreversible decay of the domain structure occurs when the domain walls are displaced by distances exceeding the elementary lattice parameter of the ferroelectric. The proposed method can be part of a comprehensive study that includes electrophysical, microscopic and X-ray diffraction measurements to determine the defective structure of a ferroelectric material. [ABSTRACT FROM AUTHOR]

Vacancies are missing atoms in a crystalline material, and occur both at equilibrium (varying with temperature) and out of equilibrium such as when crystalline materials are damaged with radiation or corrosion. While we know of their importance, particularly regarding diffusive mechanisms, it is not straightforward to experimentally measure their concentration or to visualize them directly. Traditionally, measurements such as positron annihilation spectroscopy and to some degree X-ray diffraction can measure average concentrations, but generally lack the ability to visualize or quantify a heterogenous concentration of vacancies that can occur at the level of individual defects and microstructural features. Here, we present a method to map vacancy concentrations and their distribution using local lattice parameter measurements with a high-resolution electron microscope. Our method utilizes a Au thin film as a model to demonstrate the method via four-dimensional scanning transmission electron microscopy (4D-STEM) by correlating the differences between changes in lattice parameter and the volumetric thermal expansion during in situ heating experiments. The vacancy mapping methodology is also applied to non-equilibrium defects accumulated in pure Al via knock-on electron beam irradiation. Our method demonstrates the ability to map point defect concentrations in heterogeneous systems in situ with nanometer spatial resolution. The result is a technique that can provide direct measurements of vacancy concentrations at the level of individual defects in studies of materials in and out of equilibrium.

In recent years, extensive research on dynamic precipitation has led to a growing interest in exploring how deformation affects microstructure and mechanical properties. In this study, the response of microstructure and performance to cold pre-strain and the early aging stage in the Al–Zn–Mg–Cu alloy was investigated using a combination of modelling and experimental approaches. A Kampmann-Wagner based numerical framework was developed and applied to the Al–Zn–Mg–Cu alloy. The deformation or quenching induced dislocations and vacancies, their dynamics and acceleration on the diffusivities of solute atoms, and the competition between homogeneous and heterogeneous nucleation were considered in the framework. The effect of the different pre-strain levels (0%–10%) on the evolution of vacancies, dislocations, precipitation kinetics and hardening are given in detail. The results suggest that the acceleration of precipitation kinetics and hardening during the aging process following pre-strain is primarily attributed to the overall increase in diffusivity resulting from deformation-induced dislocations, rather than vacancies. The simulation framework developed in the current work effectively captures the evolution of microstructure and mechanical properties, which has significant practical implications for materials manufacturing.

The COVID-19 pandemic produced a significant decline in international immigration to the USA between 2020 and 2021. This paper documents the timing, characteristics, and heterogeneity of the change in immigration across states and economic sectors. Additionally, we describe the trends in internal native mobility in the USA prior to and after the pandemic, investigating whether natives responded to the decrease in immigration by relocating either geographically or across sectors. Despite the substantial drop in international migration, we do not observe any significant changes in native internal mobility. Employing a panel regression and a shift-share IV, we study the effect of foreign immigration, the emergence of remote-work, and changes in labor demand on cross-state native mobility. Our results indicate that the decline in immigration following COVID-19 and the differential availability of remote-work opportunities across sectors and states did not drive changes in natives’ cross- state or cross-sector mobility.

SrTiO 3 (STO) is considered a promising high-temperature N-type thermoelectric material. However, its intrinsic insulating properties and high thermal conductivity limit the dimensionless quality factor (zT) due to its simple crystal structure and the existence of light elements. Along these lines, in this work, the optimization of the thermoelectric properties of STO-based materials was achieved by using the high temperature and high pressure (HPHT) method and adjusting the doping ratios of the La and Nb heavy elements. To enhance the doping effect, oxygen vacancies need to be formed within the sample. For this reason, titanium powder was added to the sample. Due to the confined environment induced by the high pressure, which can be attributed to the application of the HPHT method and the strong oxygen trapping ability of Ti at high temperatures, a reducing environment was attained for the samples, the latter, promoted the formation of oxygen vacancies in the synthesized samples, and semiconducting properties were achieved. The thermoelectric properties and microscopic morphology of the synthesized samples with different doping ratios of La and Nb were also thoroughly investigated. Finally, the maximum zT value obtained for the samples was 0.28@973 K. A fast, simple, and effective method for the preparation of oxygen-deficient packet-crystalline oxide materials was developed in this work, which paves the way for significantly improving their thermoelectric properties. [ABSTRACT FROM AUTHOR]

SrTiO 3 (STO)-based perovskite oxide is regarded as a promising high-temperature n-type thermoelectric material. However, its intrinsic high thermal conductivity leads to poor thermoelectric properties. Using entropy engineering, lower thermal conductivity can be obtained. However, the high configuration entropy can also lead to poor carrier mobility, which inhibits electron transport and consequently reduces the electrical conductivity. Along these lines, in this work, an ultra-low thermal conductivity was obtained, which is significantly lower than the majority of the values reported in the literature, and the concept of phononic glass electronic crystal was attained at the same time. The enhanced effective scattering of phonons through the multi-scale defects gives rise to a low thermal conductivity of 1.8 W m−1 K−1 at 973K. Optimization of electrical properties due to in situ reduction at high temperature and pressure，the high-entropy ceramics possess the maximum power factor of 7.03 μW cm−1 K−2 at 973K. The application of high pressure is considered an important approach for the development of new materials with special properties. A new strategy for the composition design and in-situ reduction of oxide thermoelectric materials was provided in this work, which paves the way for the optimization and application of both the electrical and thermal properties of perovskite-based materials. [ABSTRACT FROM AUTHOR]

The article deals with the problem of human resources in Ukraine in connection with the migration of a significant part of the working population abroad. It is proved that an enterprise that can re-profile its employees will always have human capital since the ability to teach and retrain people is becoming key in the issue of labor shortage. The article examines the relevance of the issue of personnel outflow abroad on the example of the activities of the Husiatyn furniture factory «Elegant». In order to overcome the staff shortage, the author proposes long-term and short-term models of staffing. The conditions of cooperation with the Husiatyn Vocational College of Ternopil National Technical University named after Ivan Puluj on the conclusion of an agreement on joint training of personnel in two specialties «Carpenter» and «Seamstress» were studied. It was concluded that to immediately overcome the shortage of staff in blue-collar occupations, the management of the «Elegant» furniture factory should resort to the development and application of a short-term staffing strategy through a short-term training model. First of all, sewing was chosen to implement the plan. The budget of the short-term vocational training model is calculated. It has been substantiated that the implementation of this project on time will increase the efficiency of the sewing unit by 20% due to the process of staffing with sewing personnel. This will lead to an increase in the production of furniture products and an increase in sales. The link between long-term and short-term staffing models was established. Thus, for the public confidence of the employee, after a short-term vocational training at the furniture factory «Elegant», the management of the enterprise will offer the best personnel to enter the Husiatyn Professional College in this specialty at the expense of the factory. The condition for financing training at the educational institution will be the employee's obligation to work at the furniture factory for a period equal to the training period. It is established that it is advisable for Ukrainian manufacturers to develop a competitive economic strategy aimed at increasing labor potential. Proposals from business entities should be attractive and convincing to workers and act as a guarantee of staffing. [ABSTRACT FROM AUTHOR]

The induced ferromagnetic behaviour and defect analysis of the undoped, Ni doped SrSnO 3 nanostructures are examined. The undoped and Ni doped SrSnO 3 (SSO) nanostructures crystallized in the orthorhombic perovskite structure, and show local structural disorders on vibrational spectroscopic analysis. The electron micrographs are witnessed rod type morphology for pure SrSnO 3 and corals for Ni doped compounds. The oxidation states of elements and presence of oxygen vacancies are identified. The sharp optical absorption behaviour resulted in reduction of optical band gap. Positron annihilation spectroscopy (PAS) studies reveal the presence of site-specific intrinsic defects of considerable concentration and their consequential effect on doping. PAS significantly showed that Schottky-type V Sn and V Sr-XO complexes in undoped SSO. The addition of Ni2+ results in the reduction of V Sr – O and the formation of Ni2+-V O -Ni2+ defect complexes. The EPR spectra show the signal with g value of 2.2432. The appearance of RT ferromagnetism could be attributed to the defects, F -center exchange (FCE) interactions in Ni-doped SSO nanostructures. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrocatalytic hydrogenation (ECH) reduction provides an environment-friendly alternative to conventional method for the upgrade of furfural to furfuryl alcohol. At present, exploring superior catalysts with high activity and selectivity, figuring out the reduction mechanism in aqueous alkaline environment are urgent. In this work, zinc cobalt bimetallic oxide (ZnMn 2 O 4) with surface-derived Zn2+ vacancies supported by carbon nanofibers (d- ZnMn 2 O 4 -C) was fabricated. The d- ZnMn 2 O 4 -C exhibited excellent performance in electrocatalytic reduction of furfural, high furfuryl alcohol yield (49461.1 ± 228 µmol g−1) and Faradaic efficiency (95.5 ± 0.5 %) was obtained. In-depth research suggested that carbon nanofiber may strongly promoted the production of adsorbed hydrogen (H ads), and Zn2+ vacancies may significantly lowered the energy barrier of furfural reduction to furfuryl alcohol, the synergistic effect between carbon nanofiber and d- ZnMn 2 O 4 probably facilitated the reaction between H ads and furfuryl alcohol radical, thereby promoting the formation of furfuryl alcohol. Furthermore, the reaction mechanism was clarified by inhibitor coating and isotope experiments, the results of which revealed that the conversion of furfural to furfuryl alcohol on d- ZnMn 2 O 4 -C followed both ECH and direct electroreduction mechanism. [ABSTRACT FROM AUTHOR]

The coefficient of thermal expansion mismatch (CTEM) strengthening is presumed to be among the main strengthening factors in metal matrix composites reinforced with micro- and nano-sized particulates. It is assumed that the CTEM-generated dislocations obstruct the movement of those generated, when the composite is under external load, thus strengthening the composite. An experimental study, which was carried out on as-produced aluminum-based composite, reinforced with 5 and 10 wt.% nano-sized TiCN particulates (volume fraction of TiCN, fv = 0.0306 and 0.0625), failed to detect the predicted by the theory CTEM-generated dislocations. Moreover, it was found that the reinforcement-matrix adhesion forces become weaker with the increase in the reinforcement size. An analysis of the experimental results, intended to investigate the contradiction between the experiment and the postulates of the CTEM strengthening theory, was carried out. The analysis, that implements the dislocation nucleation (Cottrell) and vacancy "drift-diffusion" (Einstein–Smoluchowski) theories, revealed that the classical CTEM strengthening mechanism is active only above a certain, critical size, of the reinforcement. It was found that below that critical size, the composite strength is controlled by the adhesion forces between the reinforcement and the matrix. The theories above predicted that the composite strength (i) would improve as the size of the reinforcement tends to the nano-scale sizes, and (ii) is at its lowest when the size of the reinforcement is commensurate with the aforementioned critical size. [ABSTRACT FROM AUTHOR]

The development of ozone-decomposition catalysts with high efficiency and exceptional resistance to humidity is a significant challenge, as ozone is a primary air pollutant. This study successfully synthesized a series of MnxFe3–xO4 catalysts with varying crystal structures by adjusting the Mn/Fe molar ratios through a coprecipitation method with inorganic salt precursors. Compared to crystalline Mn3O4 and Fe2O3, the obtained amorphous MnFe2O4(MnFe-1) nanocatalyst exhibited an optimal ozone conversion rate of 99.9% for 50 ppm O3 with a space velocity (SV) of 600 L g–1 h–1 in dry gas and 77.4% for 50 ppm O3 with a SV of 600 L g–1 h–1 under a relative humidity (RH) of 60%. The superior performance of the amorphous sample can be attributed not only to its smaller size and larger surface area but also to the presence of Mn3+ as the active site, a higher number of oxygen vacancies and acid sites, and the synergistic effect between iron and manganese. This research offers a universally applicable preparation method for nanosized spinel oxides and provides an in-depth exploration of the ozone-decomposition mechanism. [ABSTRACT FROM AUTHOR]

Implantation of heavy ions into metal matrices leads to the creation of a high concentration of radiation defects. X-ray diffraction studies of Mo and Ta foils implanted with 57Fe ions have been carried out. It is shown that the implantation of Fe ions does not significantly affect the lattice parameters. It has been established that irradiation leads to the broadening of diffraction lines and a decrease in the size of crystal grains. The Mo and Ta foils are found to be highly textured, with {100} orientation in the foil plane. Irradiation with Fe ions has no noticeable effect on the texture. However, subsequent annealing at a temperature of 700°С weakens the texture on the irradiated side for Mo and Ta foils without affecting the texture of the nonirradiated side. [ABSTRACT FROM AUTHOR]

The aging dynamics of materials used to build the active part of optoelectronic devices is a topic of current interest. We studied epitaxial samples of GaAs doped with Ge and Sn up to 1 × 10 19 cm−3, which were stored in a dry and dark environment for 26 years. Photoluminescence spectra were taken in three periods: 1995, 2001 and 2021. In the last year, time-resolved photoluminescence, Raman, and X-ray measurements were also performed to study the evolution of defects formed by the action of O2 in the samples and its correlation with the doping with Ge and Sn impurities. We found that oxygen formed oxides that gave off Ga and As atoms, leaving vacancies mainly of As. These vacancies formed complexes with the dopant impurities. The concentration of vacancies over the 26 years could be as large as 1 × 10 18 cm−3. [ABSTRACT FROM AUTHOR]

Cold spray (CS) is a rapid additive manufacturing method for deposition of metallic materials at rates significantly exceeding the laser-based methods, while retaining high deposit quality and low process cost. The mechanisms of the high-rate, extensive deformation of the materials in the CS process were recently intensively studied on macro- and meso-levels. In this paper, we introduce positron annihilation spectroscopy as a viable and reliable analytical method to study lattice defects created in the cold sprayed materials on the atomic-scale level. For the first demonstration, four different base metals were selected (Al, Cu, Ni, and Ti). A high density of dislocations was observed in all four deposits. In addition, deposits of fcc metals (Al, Cu, and Ni) also contain a considerable concentration of vacancy clusters. The results show that the extremely fast deformation in cold spray deposition process prevents recovery of vacancies which tend to agglomerate into clusters. [ABSTRACT FROM AUTHOR]

Beryllium (Be) intermetallic compounds (beryllides) are promising materials for neutron multiplication in fusion reactors. In particular, titanium beryllide (Be12Ti) exhibits low swelling and good corrosion resistance compared to other beryllides. Herein, the defects in neutron‐irradiated Be12Ti are investigated using positron annihilation spectroscopy, and the results are analyzed based on positron annihilation calculations. Calculation results indicate that the positron lifetime in a perfect Be12Ti crystal is 134.2 ps, while that of a Be monovacancy is found to be within the 177.3–195.0 ps range, depending on the configuration of the monovacancy. On the other hand, the positron lifetime of the Ti monovacancy is 222.7 ps. In addition, the lifetimes of the Be and Ti vacancy clusters increase with an increase in the number of vacancies. Finally, the positron lifetimes of the antisite defects in different configurations are found to be within the 137.9–141.7 ps range. In contrast to the calculated results, the positron lifetime of unirradiated Be12Ti is 141.1 ps. Furthermore, in the neutron‐irradiated Be12Ti, no vacancies are detected and only Be dislocation loop formation occur based on the calculation results. Although the irradiation dose of Be12Ti is low, its irradiation resistance is satisfactory. [ABSTRACT FROM AUTHOR]

Abstract The inefficiency of electrocatalysts for water splitting in neutral media stems from a comprehensive impact of poor intrinsic activity, a limited number of active sites, and inadequate mass transport. Herein, hierarchical ultrathin NiCo2Se4 nanosheets are synthesized by the selenization of NiCo2O4 porous nanoneedles. Theoretical and experimental investigations reveal that the intrinsic hydrogen evolution reaction (HER) activity primarily originate from the NiCo2Se4, whereas the high oxygen evolution reaction (OER) performance is related to the NiCoOOH due to the structural reconstruction. The abundant Se and O vacancies introduced by atomically thin nanostructure modulate the electronic structure of NiCo2Se4 and NiCoOOH, thereby improving the intrinsic HER and OER activities, respectively. COMSOL simulation demonstrate the edges of extended nanosheets from the main body significantly promote the charge aggregation, boosting the reduction and oxidation current during HER/OER process. This charge aggregation effect notably exceeds the tip effect for the nanoneedle, highlighting the unique advantage of the hierarchical nanosheet structure. Benefiting from abundant vacancies and unique nanostructure, the hierarchical ultrathin nanosheet simultaneously improve the thermodynamics and kinetics of the electrocatalyst. The optimized samples display an overpotential of 92 mV for HER and 214 mV for OER at 100 mA cm−2, significantly surpassing the performance of currently reported HER/OER catalysts in neutral media.

In nanocrystalline metals, there are grain boundaries that, under the influence of shear stresses applied along them, move along the normal. Such boundaries combine two types of the grain boundary deformation – mutual grain slippage along the boundary and its migration. This relationship is easily explained in the model of intercrystalline boundaries with mating crystallographic planes. By solving the differential equation under the action of alternating voltage, the functional dependence of the boundary displacement on the coordinate and time is found. Based on this, the value of the energy dissipated during the oscillation period and the expression for the internal friction caused by the contribution of such boundaries are found. It has the character of a Debye peak. The activation energy of the process is equal to the activation energy of the grain boundary self-diffusion. An atomic mechanism of the boundary motion is proposed, which is based on diffusion processes between extended steps of atomic scale in the boundary.

The National Development Plan (NDP) (2030) refers to the professionalisation of public service in South Africa. In support of the NDP, the National Framework towards Professionalisation of Public Sector was developed to address the current challenges of unethical, incompetence and unprofessionalism of public servants as it hinders service delivery and the effectiveness of South Africa as a developmental state. For South Africa to achieve its developmental goal, it is necessary to professionalise the public service sector. This article explores the inconsistency of academic qualifications, years of experience, and positions for forensic investigations careers in South Africa's public sector. The article focuses on successful candidates to be appointed as forensic/ fraud investigators and to check if the normal recruitment process has been followed. The study adopted a qualitative research approach to gather and analyse data. The researcher utilised various job adverts from different government institutions related to forensic investigations and anti-corruption vacancies in this study. The study established that as part of the government's effort to professionalise public service, an advert with preferred requirements for the post will be published, followed by a shortlist of qualified applicants and interviews with the candidates. The study found inconsistencies regarding academic qualifications and years of experience required when positions of forensic investigations are advertised in South Africa's public sector.

FeNi oxides/hydroxides are the best performing catalysts for oxidizing water at basic pH. Consequently, their improvement is the cornerstone to develop more efficient artificial photosynthetic systems. During the last 5 years different reports have demonstrated an enhancement of their activity by engineering their structures via: (1) modulation of the number of oxygen, iron and nickel vacancies; (2) single atoms (SAs) doping with metals such as Au, Ir, Ru and Pt; and (3) modification of their surface using organic ligands. All these strategies have led to more active and stable electrocatalysts for oxygen evolution rection (OER). In this Concept, we critically analyze these strategies using the most relevant examples. [ABSTRACT FROM AUTHOR]

How and why the reliability of ferroelectric HfO2‐ and HZO (Hf0.5Zr0.5O2)‐based memory devices strongly depends on the choice of electrode materials is currently under intense discussion. Interface conditions such as band alignment, defect formation, and doping are recognized as decisive and interrelated parameters, but a unified picture of the physical mechanisms is still missing. Here, two opposite scenarios of band alignment are found in TiN/HZO/TiN and IrO2/HZO/IrO2 using hard X‐ray photoelectron spectroscopy, revealing on the one hand the conditions for a stable device performance, and the origin of their degradation on the other. As a key difference, TiN electrodes scavenge oxygen from the HZO, while IrO2 electrodes supply it. Considering the electronic doping limit of HfO2, a key condition for the stability of ferroelectric devices can be identified: The alignment of the charge neutrality levelwith respect to the metallic Fermi level, which is pinned by the doping limit. Stable device performance can only be achieved for oxygen‐deficient HfO2‐based interfaces, where the Fermi level of the metal electrode is close to the conduction band of the ferroelectric insulator. This empirical model explains the fatigue behavior of HfO2‐based capacitors using either oxygen‐scavenging TiN or oxygen‐supplying IrO2 electrodes. [ABSTRACT FROM AUTHOR]

Yttria‐stabilized zirconia (YSZ), although well known for a lot of excellent engineering applications, has limited footprints in the field of adsorption/dye removal. Through this work, we demonstrate the remarkable efficacy (adsorption capacity ∼550 mg/g) of 8 mol.% YSZ nano‐adsorbents for toxic azo‐dye (e.g., Congo red) removal. The consistency of our adsorption experiments was validated with the help of a series of tests, such as regeneration (via thermal and chemical routes), in real‐life river water, with mixed ion solution, and under varied pH (3–11). Noteworthy is also that the commercial trademark composition (with the same dopant concentration) showed little/no adsorption. Our success of the adsorption experiments is credited to the multitude of factors, namely, size refinement ∼6 nm, retainment of phase‐pure cubicity, and enhanced surface area (155 m2/g), which eventually led to the generation of massive oxygen vacancies on our synthesized doped‐zirconia surfaces. [ABSTRACT FROM AUTHOR]

Nanocrystalline metals possessing excellent mechanical strength have great potential to replace traditional metal materials as structural materials, but their poor resistance to creep deformation seriously restricts their engineering applications at high temperatures. The high-temperature creep behavior of nanocrystalline Ni with different volume fractions of initial vacancies ranging from 0% to 10% was studied systematically by molecular dynamics simulation in this study. The results showed that the steady-state creep displacement first increased and then decreased with increasing initial vacancy concentration, reaching the maximum when the initial vacancy concentration was 6%. The microstructural characteristics, such as quantity increment and distribution of the vacancies, the number and types of dislocations, and shear strain distribution during creeping, were analyzed in detail. The deformation-induced vacancies formed at the grain boundary (GB) in the initial creep stage, and their variation trend with the initial vacancy concentration was consistent with that of the creep displacement, indicating that the initial vacancy-dependent high-temperature creep behavior of nanocrystalline Ni was mainly determined by the rapidly increasing number of vacancies at the GB in the initial creep stage. Afterwards, the deformation-induced, vacancy-assisted 1/6{112} Shockley partial dislocation activities dominated the creep deformation of nanocrystalline Ni in the steady-state creep stage. The results can provide theoretical support for expanding the application of nanocrystalline metals from the perspective of crystal defect engineering. [ABSTRACT FROM AUTHOR]

The effect of pulsed electron beam (PEB) irradiation modes on the structure and defect formation and the mechanical strength in the near-surface layer of a Zr–1 wt % Nb alloy with a hydrogen content of 0.0016 and 0.21 wt % (hereinafter, Zr–1Nb and Zr–1Nb–0.21H alloys, respectively) has been studied. By using optical and electron microscopy, as well as X-ray diffraction analysis, it was established that irradiation of the Zr–1Nb and Zr–1Nb–0.21H alloys in the mode without surface melting did not change the morphology and phase composition of their structure. After irradiation with a PEB in the surface melting mode, the dissolution of particles of the β-Nb phase and the formation of a lamellar structure were observed in the near-surface layer of the alloys regardless of the hydrogen concentration. It was shown by positron annihilation that irradiation in the mode without surface melting led to the formation of dislocations and vacancies in the near-surface layer. In the near-surface layer of the alloys irradiated with a PEB in the surface melting mode, in addition to dislocations and vacancies, defects of the "vacancy-impurity" type were formed. The presence of hydrogen in the alloy contributed to the formation of complex hydrogen-vacancy complexes in the surface layer during irradiation with a PEB. The mechanical strength of the near-surface layer of the alloys was determined depending on the mode of irradiation with a PEB. It is shown that the formation of a lamellar structure in the near-surface layer led to an increase in the strength characteristics of the Zr–1Nb and Zr–1Nb–0.21H alloys under tension in the temperature range of 293–673 K by 25–10%. [ABSTRACT FROM AUTHOR]

The mechanism of structure transformation in Cr/4H–SiC UV photo detectors, which is responsi-ble for the cyclic gettering of radiation defects, under repeated proton irradiation, is proposed in this work. [ABSTRACT FROM AUTHOR]

Despite the fast growth in the Estonian economy, unemployment has remained high for extended periods of time. This paper analyses and quantifies the mismatch between registered unemployment and vacancies and how it has contributed to unemployment in the Estonian labour market at the (county) regional, occupational, and industrial levels for the time span 2011-2021. We apply the search and matching theory and the mismatch index framework, and our findings show that around 4–5 per cent of potential hires have been lost in the Estonian labour market because of mismatch. The contribution of mismatch to the level of unemployment is roughly 5–8 per cent, meaning that if the match between unemployed individuals and vacancies was efficient, unemployment would have been 5–8 per cent lower. Mismatch has the smallest impact at the regional level and the largest at the industrial level. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental study of the structure of the Zr–1Nb alloy after modification by a high-current pulsed electron beam. The defective and phase structures were studied by the X-ray diffraction, positron lifetime spectroscopy, and Doppler broadening methods. The surface layer modification under electron-beam treatment was caused by the formation of a liquid phase and its subsequent congelation at the end of the pulse. It is shown that after the modification considerable changes of the annihilation parameters related to the change of the defect structure on the surface and in the volume of the material took place. Depending on the irradiation regime, the redistribution of positron annihilation probability between the two types of defects was observed. The pulsed electron beam irradiation of the Zr–1Nb alloy significantly changed the surface and structure of defects to a depth of up to 100 µm. It is shown that after the alloy modification by a pulsed electron beam, dislocation loops and vacancy-type defects prevailed. [ABSTRACT FROM AUTHOR]

We provide insights on how job search changed in the Covid-19-crisis by analysing data from the LinkedIn professional network for Germany. We find that competition among workers for jobs strongly increased – which is due to additional job seekers rather than higher search intensity. Furthermore, the LinkedIn data show that people from industries particularly affected by the crisis applied much more frequently and there had been a substantial shift in the target industries for applications. Finally, we find that at the onset of the Covid-19-crises applications were made significantly more often below and significantly less often above a person's level of seniority. [ABSTRACT FROM AUTHOR]