Search

The relative errors of virtual cathodes calculated by using the one-dimensional virtual cathode theory are analyzed and discussed. The studies of the error analysis show that the cathode temperature is the major factor affecting the calculated results of virtual cathodes, especially for calculations of the virtual cathode width. The smaller the virtual cathode produced by a hot cathode, the more significant the relative error of the virtual cathode caused by the uncertainties of electron emission parameters. Using the accurate cathode temperature, the potential barrier and the spatial width of virtual cathodes generated by a tungsten filament are calculated with experimental and theoretical electron emission parameters. The calculated results show that there is a strong linear correlation between the potential barrier of the virtual cathode and the heating current of the tungsten filament, which is independent of the electron collection current. With the increase in the heating current, the variation of the virtual cathode width is very sensitive to the relation between the electron collection current and the heating current. [ABSTRACT FROM AUTHOR]

We conduct molecular dynamics simulations of helium in tungsten to study the interaction of helium with grain boundaries. Model systems with grain boundary planes perpendicular to the surface and parallel to the surface are considered. The net attraction of mobile helium to the grain boundary results in a "depleted region" within approximately 3.5 nm of the grain boundary plane at low fluence, and once on the plane of the grain boundary, helium transport slows considerably. Helium retention is also strongly affected by the grain boundaries and their density: grain boundary planes approximately 6 nm beneath the plasma-facing surface and parallel to the surface tend to reduce the maximum bubble size due to the attraction of mobile clusters to the grain boundary plane, which lowers the concentration of helium near the surface (where it is being implanted); grain boundaries perpendicular to the surface tend to increase retention due to retention on the grain boundary plane. For grain boundaries parallel to the surface, the strong gettering effect of the grain boundaries on helium results in essentially no helium penetration through the grain boundary during the first 1.5 μs of plasma exposure at a flux of 1.6 × 10 25 m − 2 s − 1 , corresponding to fluences on the order of 10 20 m − 2 . Coarse-grained simulations capable of capturing the long-term dynamics of helium aggregation near grain boundaries would be required to determine whether these effects would have any measurable impact on phenomena, such as tungsten fuzz growth. [ABSTRACT FROM AUTHOR]

A gradient nano-grained (GNG) structure demonstrates satisfactory surface strength. However, the underlying mechanism responsible for its strengthening lacks sufficient research. To explain how gradient nano-grained structures improve surface strength in detail, large-scale parallel molecular dynamics simulations are utilized in this study to investigate the mechanical deformation behavior of BCC tungsten with varying grain sizes during spherical nanoindentation. The findings suggest that a well-designed gradient structure can promote rational plasticity and an appropriate distribution of internal atomic stress. The critical point of maximum stress and hardness is observed when the initial grain size is 4.5 nm, with an average grain size of 7.1 nm. The interaction between grain boundary slip and migration in small grains, along with the enhanced activity of grain boundary dislocations in large grains, collectively contributes to the enhancement of the strength and hardness of the GNG structure. Compared with a homogeneous nano-grained structure, the gradient nano-grained structure exhibits a more rational distribution of dislocations and stress relaxation effects to enhance strength. The present work utilizes the molecular dynamics nanoindentation method to study GNG materials, providing a methodology for investigating the surface strengthening effects of GNG structures at the atomic scale and effectively revealing potential mechanisms for resisting surface deformation in GNG structures. [ABSTRACT FROM AUTHOR]

In this work, the distribution and segregation behaviors of helium (He) and the effect of yttrium (Y) on these behaviors in the symmetrical tilt tungsten (W) Σ5(310)/[001] grain boundary (GB) region were studied using first-principles calculations. The results revealed that the GB has a significant impact on the behaviors of He in W. The solution and segregation energies of He in the W Σ5(310)/[001] GB region increase with increasing the distance from He to the GB and are inversely proportional to the effective electrons of He. The density of states analysis showed that the GB can suppress partial hybridization between He and W atoms. In addition, we find that the strengthening element Y facilitates the dissolution of He in the W GB region. [ABSTRACT FROM AUTHOR]

The intriguing network of antibody–antigen (Ab–Ag) interactions is highly governed by environmental perturbations and the nature of biomolecular interaction. Protein–protein interactions (PPIs) have potential applications in developing protein-adsorption-based sensors and nano-scale materials. Therefore, characterizing PPIs in the presence of a nanomaterial at the molecular level becomes imperative. The present work involves the investigation of antiferritin–ferritin (Ab–Ag) protein interactions under the influence of tungsten disulfide quantum dots (WS2 QDs). Isothermal calorimetry and contact angle measurements validated the strong influence of WS2 QDs on Ab–Ag interactions. The interfacial signatures of nano–bio-interactions were evaluated using sum frequency generation vibration spectroscopy (SFG-VS) at the air–water interface. Our SFG results reveal a variation in the tilt angle of methyl groups by ∼12° ± 2° for the Ab–Ag system in the presence of WS2 QDs. The results illustrated an enhanced ordering of water molecules in the presence of QDs, which underpins the active role of interfacial water molecules during nano–bio-interactions. We have also witnessed a differential impact of QDs on Ab–Ag by raising the concentration of the Ab–Ag combination, which showcased an increased inter-molecular interaction among the Ab and Ag molecules and a minimal influence on the methyl tilt angle. These findings suggest the formation of stronger and ordered Ab–Ag complexes upon introducing WS2 QDs in the aqueous medium and signify the potentiality of WS2 QDs relevant to protein-based sensing assays. [ABSTRACT FROM AUTHOR]

Understanding the behavior of intrinsic defects and helium (He) in tungsten oxides is useful for the application of tungsten (W) in a fusion environment because of the oxidation of W surfaces. The formation and diffusion energies of intrinsic defects and He in monoclinic γ-WO3 have been investigated using first-principles density functional theory calculations. The formation energy and diffusion activation energy of O defects are lower than W defects. O vacancy prefers to diffuse along the ⟨ 001 ⟩ direction, then followed by ⟨ 010 ⟩ and ⟨ 100 ⟩ directions; however, the W vacancy is immobile at temperatures lower than 2000 K. The stability of Schottky defects (SDs) is sensitive to their geometry and orientation. W interstitials prefer to move along the [100] direction, while O interstitials jump around W atoms rather than through the W quasi-cubic centers. He interstitial atoms are predicted to have a high solubility and an anisotropic diffusion mechanism in γ-WO3. In addition, the effect of biaxial strain on the solubility and diffusivity of He interstitials was investigated. He interstitials prefer to reside at individual sites rather than clusters. He atoms are weakly trapped by single vacancies or SDs. Vacancies assist the local migration of nearby He. Correspondingly, He self-clustering and bubble formation are less likely to form in γ-WO3 relative to bcc W. The energetics obtained in this work can be used to predict the microstructure evolution of the WO3 layer on a W substrate exposed to He plasmas at different temperatures. [ABSTRACT FROM AUTHOR]

Utilization of metal tungsten (W) as the structural material or pressure scale requires accurate knowledge of the equation of state (EOS), which is far beyond the available experimental measurements. In the present work, a direct integral approach (DIA) with ultrahigh efficiency was applied to calculate the EOS of W up to 500 GPa and 3000 K with ab initio calculations. Compared with previous static compression experiments up to 150 GPa under room temperature and 35 GPa at high temperatures up to 1673 K, all the deviations of the calculated pressure are within or comparable to the uncertainty of experiments. Predictions for higher-temperature and simultaneously higher-pressure EOS up to 300 GPa and 3000 K differ slightly from the comprehensive analysis by Litasov et al. [J. Appl. Phys. 113, 133505 (2013)] via fitting available experimental data with the empirical equation. These results indicate that the EOS of crystal W obtained from DIA should be convincible, and DIA without any empirical or artificial parameters may find its wide applications for predicting thermodynamic properties of condensed matter in the future. [ABSTRACT FROM AUTHOR]

We demonstrate a high electron conductivity (>102 S/cm and up to 103 S/cm) of tungsten suboxide W18O52.4−52.9 (or equivalently WO2.91−2.94) nanotubes (2–3 nm in diameter, ∼μm long). The conductivity is measured in the temperature range of 120–300 K by a four-probe scanning tunneling microscope in ultrahigh vacuum. The nanotubes are synthesized by a low-temperature and low-cost solvothermal method. They self-assemble in bundles of hundreds of nanotubes forming nanowires (∼μm long, few tens nm wide). We observe a large anisotropy of the conductivity with a ratio (longitudinal conductivity/perpendicular conductivity) of ∼105. A large fraction of them (∼65%–95%) shows a metallic-like, thermal activation-less electron transport behavior. Few of them, with a lower conductivity from 10 to 102 S/cm, display a variable range hopping behavior. In this latter case, a hopping barrier energy of ∼0.24 eV is inferred in agreement with the calculated energy level of the oxygen vacancy below the conduction band. This result is in agreement with a relative average concentration of oxygen vacancies of ∼3%, for which a semiconductor-to-metal transition was theoretically predicted. These tungsten suboxide nanostructures are prone to a wide range of applications in nanoelectronics. [ABSTRACT FROM AUTHOR]

In this study, tungsten oxide nanosheets loaded with nitrogen-doped graphene oxide quantum dots (NGQDs/WO3 NSs) were fabricated as SERS substrates. The promoted photo-induced charge transfer (PICT) and the strong π–π stacking effect resulting from the unique structure of the NGQDs contributed to the enhanced SERS signal. [ABSTRACT FROM AUTHOR]

Nano tungsten carbide (WC) was synthesized using loose yellow tungsten oxide (WO3) rods, which were derived from violet tungsten oxide (WO2.72) through calcination in dry oxygen. The WO3 rods were then subjected to ball milling with carbon black, followed by carbothermal reduction and carbonization. Unlike conventional methods such as hydrogen reduction or carbothermal reduction, this technique avoids the formation of hydrated tungsten oxides and addresses challenges related to precise carbon control and matching. This streamlined procedure produces nanoscale tungsten carbide particles approximately 150 nm in size, showing great potential for future industrial applications. [ABSTRACT FROM AUTHOR]

The pressure limit of the conventional cubic press is normally below 6 GPa, and the suitable pressure calibrant of the fixed-point method is scarce. In this study, we developed a new method for pressure determination using an acoustic travel time approach. Based on the reported ultrasonic travel times of polycrystalline molybdenum under high pressure in literature, an acoustic gauge of polycrystalline molybdenum was derived. The shear wave travel times of molybdenum were measured at high pressures and utilized for the pressure calibration in a cubic press. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point method. Subsequent compressional and shear wave velocities of polycrystalline tungsten were measured up to about 5 GPa at room temperature to further verify this method. This travel time method for pressure calibration is valuable for the sound velocity measurement of other materials in an offline laboratory. [ABSTRACT FROM AUTHOR]

Leak proof tube-to-tube sheet joints are mandatory for the optimal operation and longevity of the shell and tube heat exchanger. Tube-to-tube sheet joints play a crucial role as fluid barriers, ensuring effective separation between the tube and shell side fluids within shell and tube heat exchangers. Nonconventional friction stir welding, known for imparting less residual stresses, is not commercially used for the fabrication of tube-to-tube sheet joints due to complex joint configuration and geometrical limitations. An extensive study on friction stir welding considering the geometrical parameters of tube-to-tube sheet arrangement is highly demanded. This research examined the mutual influence of radial clearance ranging from 0 mm to 0.5 mm and tube projection lying from 1 mm to 2 mm in friction stir welding of tube to tube sheet configuration on the pull-out strength, extension and, hardness at the stirring and fusion zones. Optimum radial clearance and tube projection for achieving high mechanical weld properties was estimated using multi-objective integrated Taguchi-PCA-GRA optimization. The result proves that the friction stir welded joint is capable of achieving joint strength close to the tungsten inert gas welded joint. The optimum parameters are 2 mm for tube projection and 0 mm for radial clearance to achieve maximum strength and weld penetration, while minimizing hardness at both stir zone and fusion zone. The findings of this research proved the adaptability of friction stir welding for the fabrication of tube-to-tube sheet joints with the right choice of tube projection and radial clearance. [ABSTRACT FROM AUTHOR]

In this paper, a perfect absorber (PA) based on tungsten is proposed to include hexagonal‐shaped metasurface absorbers with varying hole sizes ranging from quadrangular to circular, allowing them to cover a wide wavelength spectrum. The study investigates the effects of various parameters, including the number of sides of the inner hole, on the absorber's performance and identifies the most suitable absorber by introducing an equivalent circuit. The outcomes of full‐wave numerical simulations primarily based on the finite element method (FEM) highly correspond to the final results of the circuit model. Additionally, the circuit model significantly reduces computation time and requires less storage compared with full‐wave simulations. The results show that the hexagonal‐square metasurface absorber achieves exceptional absorption rates, with an average of 99.9% in the 431 to 532 nm wavelength range and over 90% in the 300 to 915 nm range. The hexagonal‐hexagonal metasurface absorber also exhibits high absorption rates, with an average of over 99% in the 431 to 518 nm and 700 to 780 nm ranges, and over 90% in the 300 to 940 nm range. The absorption performance of the proposed hexagonal‐circle metasurface absorber is also remarkable, with an absorption value of over 99% in the 670 to 771 nm range and above 90% in the 365 to 991 nm range. These models can be utilized to design and simulate other subwavelength absorbers in a broad frequency range, including terahertz and visible light, making them suitable for various applications. [ABSTRACT FROM AUTHOR]

Ambient-condition acetylene hydrogenation to ethylene (AC-AHE) is a promising process for ethylene production with minimal additional energy input, yet remains a great challenge due to the difficulty in the coactivation of acetylene and H2 at room temperature. Herein, we report a highly efficient AC-AHE process over robust sulfur-confined atomic Pd species on tungsten sulfide surface. The catalyst exhibits over 99% acetylene conversion with a high ethylene selectivity of 70% at 25 oC, and a record space-time yield of ethylene of 1123 molC2H4 molPd−1 h−1 under ambient conditions, which is nearly four times that of the typical Pd1Ag3/Al2O3 catalyst, and exhibiting superior stability of over 500 h. We demonstrate that the confinement of Pd-S coordination induces positively-charged atomic Pdδ+, which not only facilitates C2H2 hydrogenation but also promotes C2H4 desorption, thereby enabling a high conversion of C2H2 to C2H4 at room temperature while suppressing over-hydrogenation to C2H6. Ambient-condition acetylene hydrogenation to ethylene (AC-AHE) is a promising process for ethylene production yet remains a challenge. Here the authors report a highly efficient AC-AHE process over robust sulfur-confined atomic Pd species on tungsten sulfide surface, achieving over 99% conversion and 70% selectivity, with a record-breaking ethylene yield and excellent stability exceeding 500 h at 25 °C. [ABSTRACT FROM AUTHOR]

In this study, the WIEN2k code, utilizing the full potential linearized augmented plane wave (FPLAPW) approach within the framework of density functional theory (DFT), explicitly employing the PBEsol approximation, is employed to investigate the fundamental properties of W-doped and (Mo, W) co-doped cubic CeO2. Herein, lattice constants, bulk modulus and cell volumes were evaluated for structural properties. The total density of states (TDOS) for various doped and co-doped CeO2 systems was used to explain the origin of magnetic behavior. The band structure (BS) calculations show that the doped and co-doped materials exhibit semiconductor behavior with a direct bandgap in both spin channels. The calculated total spin magnetic moments of W/CeO2 and (Mo, W)/CeO2 alloys are 2.002 μ B and 4.007 μ B , respectively. Furthermore, the optical absorption shows absorption peaks in the visible range and a redshift. As a result, adding molybdenum and tungsten additives improves the electro-optical properties of previous materials. [ABSTRACT FROM AUTHOR]

Current additive manufacturing (AM) techniques for tungsten, such as powder bed fusion and directed energy deposition, often generate parts with rough surfaces. Vat photopolymerization presents a promising alternative for fabricating tungsten structures with high shape fidelity and low surface roughness. However, existing vat photopolymerization approaches suffer from surface defects and low final density, leading to compromised mechanical properties. Therefore, achieving high‐density tungsten structures using vat photopolymerization remains a crucial challenge. This work presents a straightforward and reliable method for fabricating complex, micro‐architected tungsten structures with superior density and hardness. The approach utilizes a water‐based photoresin with exceptional tungsten ion loading capacity. The photoresin is then patterned using digital light processing (DLP) to create tungsten‐laden precursors. A three‐step debinding and sintering process subsequently achieves 3D tungsten structures with dense surface morphology and minimal internal defects. The microstructures achieve a minimum feature size of 35 µm, a low surface roughness of 2.86 µm, and demonstrate exceptional mechanical properties. This new method for structuring tungsten opens doors to a broad range of applications, including micromachining, collimators, detectors, and metamaterials. [ABSTRACT FROM AUTHOR]

In this study, the influence of the thickness of the channel layer on the electrical properties and stability of tungsten-doped indium oxide (IWO) thin-film transistors (TFTs) was investigated. Although oxide-semiconductor TFTs, particularly indium gallium zinc oxide, are promising, problems related to oxygen vacancies have led to their instability. In contrast, IWO has proven to be a compelling alternative because of its robust resistance to oxygen vacancies. IWO TFTs with varying channel thicknesses (10, 20, and 30 nm) were fabricated, and the device parameters, such as threshold voltage (Vth), subthreshold swing (SS), field-effect mobility (μFE), and on/off current ratio (Ion/Ioff), were analyzed. It was found that as the channel thickness increased, Vth exhibited a negative shift and SS increased, indicating an increase in carrier concentration. This phenomenon is attributed to the bulk trap density, in particular to oxygen vacancies. Negative bias stress tests confirmed the influence of the oxygen vacancies, with thicker channels showing more pronounced shifts. Low-frequency noise measurements were consistent with the carrier number fluctuation model, indicating that defects within the channel region contribute to the observed noise. The study concludes that identifying an optimal channel thickness during device manufacturing is crucial for improved TFT performance, with 20 nm devices characterized by high μFE and comparable trap density to 10 nm. This study provides valuable insight into the nuanced relationship between the channel thickness, trap density, and electrical performance of IWO TFTs. [ABSTRACT FROM AUTHOR]

In light of the extensive use of tungsten (W) in fusion experimental devices and the importance of hydrogen isotopes permeation, based on the first principle approaches we study the effects of W doping on the formation energies of intrinsic point defects, hydrogen interactions with such defects, and hydrogen diffusion in bulk of α-Al 2 O 3. Our investigation demonstrated that W doping enhances the formation of oxygen and aluminum vacancies (Vo and V Al) in α-Al 2 O 3. In W doping α-Al 2 O 3 , hydrogen primarily exists in the form of Ho− (hydrogenation of the bulk V O 3−) and Hi− (H interstitial) defects, while it hardly occupies V Al. Hydrogen is firmly trapped by Vo with a formation energy −3.35eV, and Hi− diffusion become extremely challenging because W doping significantly raises the Hi− diffusion barrier to 4.44 eV. Our findings indicate that W doping is beneficial for hydrogen permeation resistance in α-Al 2 O 3. • W doping in α-Al 2 O 3 promotes oxygen and aluminum vacancies (Vo and V Al). • Hydrogen is firmly trapped by Vo (formation energy: −3.35eV) and rarely occupies V Al. • Hydrogen exists as Hi− (H interstitial) and Ho− (hydrogenation of bulk V O 3−). • W doping increases the migration barrier for Hi− to 4.44 eV, significantly limiting hydrogen permeation in α-Al 2 O 3. [ABSTRACT FROM AUTHOR]

Tungsten-doped TiO2 thin films were prepared by sol–gel method on fluorine-doped tin oxide-coated substrates as working electrodes of dye-sensitized solar cells. The influences of different W doping (0, 2, 4, 6, and 8 at%) on the microstructure, optical, and photovoltaic properties of the W-TiO2 thin-film DSSCs were studied by the measurement of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, and electrochemical impedance spectroscopy (EIS). An optimal DSSCs performance was observed with a 6 at% W-doped TiO2 thin film, resulting in a Voc of 0.68 V, a Jsc of 20.2 mA/cm2, an FF of 68.6%, and an efficiency (η) of 9.42%. The efficiency of DSSCs with 6 at% W-doped TiO2 photoanode improved by 75%. This is because the 6 at% W-doped TiO2 thin film increases the specific surface area and electron transfer rate. [ABSTRACT FROM AUTHOR]

Tungsten is a crucial strategic metal that plays a significant role in various fields, such as the defense industry, fine chemicals, and the preparation of new materials. During the practice of numerous tungsten smelting processes, a large amount of acidic wastewater containing low concentrations of WO3 is generated. The adsorption method, known for its simplicity, effectiveness, and ease of operation, represents the most promising approach for tungsten recovery and is vital for the sustainable development of the tungsten industry. In this study, D318 macroporous resin was used as an adsorbent to investigate its effectiveness in adsorbing WO3 from acidic solutions. Static adsorption experiments revealed that the adsorption capacity of D318 resin for WO3 was 683 mg·g−1. Kinetic analysis indicated that the controlling step for the adsorption of WO3 from acidic solutions by D318 resin was intraparticle diffusion. Thermodynamic analysis demonstrated that the adsorption process was endothermic and could occur spontaneously. By fitting the isothermal adsorption equation, it was found that the Langmuir model was more suitable for describing the adsorption process of WO3 on D318 resin in acidic solutions. The results of dynamic adsorption experiments showed that under optimized conditions, the dynamic adsorption capacity for WO3 was 529 mg·g−1; when using NaOH as the desorbent for cyclic desorption, the desorption rate for WO3 was 98.21%. XPS and SEM-EDS testing and analysis confirmed that D318 macroporous resin exhibited excellent adsorption performance for tungsten in acidic solutions. [ABSTRACT FROM AUTHOR]

Exposure to metals, a newly recognized risk factor for cardiovascular disease (CVD), could be related to atherosclerosis progression. The authors hypothesized that higher urinary levels of nonessential (cadmium, tungsten, uranium) and essential (cobalt, copper, zinc) metals previously associated with CVD would be associated with baseline and rate of change of coronary artery calcium (CAC) progression, a subclinical marker of CVD in MESA (Multi-Ethnic Study of Atherosclerosis). We analyzed data from 6,418 MESA participants with spot urinary metal levels at baseline (2000-2002) and 1 to 4 repeated, continuous measures of CAC over a 10-year period. We used linear mixed-effect models to assess the association of baseline urinary metal levels with baseline CAC and cumulative change in CAC over a 10-year period. Urinary metals (μg/g creatinine) and CAC were log transformed. Models were adjusted for baseline sociodemographic factors, estimated glomerular filtration rate, lifestyle factors, and clinical factors. At baseline, the median CAC was 6.3 (Q1-Q3: 0.7-58.2). Comparing the highest to lowest quartile of urinary cadmium, CAC levels were 51% (95% CI: 32%, 74%) higher at baseline and 75% (95% CI: 47%, 107%) higher over the 10-year period. For urinary tungsten, uranium, and cobalt, the corresponding CAC levels over the 10-year period were 45% (95% CI: 23%, 71%), 39% (95% CI: 17%, 64%), and 47% (95% CI: 25%, 74%) higher, respectively, with no difference for models with and without adjustment for clinical factors. For copper and zinc, the corresponding estimates dropped from 55% to 33% and from 85% to 57%, respectively, after adjustment for clinical factors. The associations of metals with CAC were comparable in magnitude to those for classical CVD risk factors. Exposure to metals was generally associated with extent of coronary calcification at baseline and follow-up. These findings support that metals are associated with the progression of atherosclerosis, potentially providing a novel strategy for the prevention and treatment of atherosclerosis progression. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of tungsten powder reduction furnace tube are investigated in this work. After service, the lamellar and skeleton-shape primary carbides of FeCr26Ni36Co15W5 alloy coarsened and formed a continuous network, much fine secondary carbide precipitated in the dendrite interior. The tensile strength and ductility of FeCr26Ni36Co15W5 alloy decreased. And, the creep strength of FeCr26Ni36Co15W5 alloy has reached the end of the service life. Meanwhile, the corrosion products were studied by XRD and XRF. It was found that the corrosion products were Na2WO4·2 h2O, Na2CO3·H2O and Cr4Ni15W，and the evaporation of catalyst (Na2CO3) results in a large amount of Na2CO3·H2O in the corrosion products. The hot corrosion mechanism of the reduction furnace tube is Type I hot corrosion. [ABSTRACT FROM AUTHOR]

A distinguishing feature of MAX phases and their MXene derivatives is their remarkable chemical diversity. This diversity, coupled with the 2D nature of MXenes, positions them as outstanding candidates for a wide range of electrochemical applications. Chemical disorder introduced by a solid solution can improve electrochemical behavior. Up to now, adding considerable amount of tungsten (W) in MAX phase and MXenes solid solutions, which can enhance electrochemical performance, proved challenging. In this study, the synthesis of M site Ti1‐xWx solid solution MAX phases are reported. The 211‐type (Ti1‐xWx)2AlC exhibits a disordered solid solution, whereas the 312‐type (Ti1‐xWx)3AlC2 displays a near‐ordered structure, resembling o‐MAX, with W atoms preferentially occupying the outer planes. Solid‐solution MXenes, Ti2.4W0.6C2Tz, and Ti1.6W0.4CTz, are synthesized via selective etching of high‐purity MAX powder precursors containing 20% W. These MXenes are evaluated as sodium‐ion battery anodes, with Ti1.6W0.4CTz showing exceptional capacity, outperforming existing multilayer MXene chemistries. This work not only demonstrates the successful integration of W in meaningful quantities into a double transition metal solid solution MAX phase, but also paves the way for the development of cost‐effective MXenes containing W. Such advancements significantly widen their application spectrum by fine‐tuning their physical, electronic, mechanical, electrochemical, and catalytic properties. [ABSTRACT FROM AUTHOR]

Trace metals are required as cofactors in metalloproteins that are essential in microbial metabolism and growth. The microbial requirements of diverse metals and the capabilities of prokaryotic taxa to acquire these metals remain poorly understood. We present here results from metagenomic observations over an entire productive season in the region off Kerguelen Island (Indian Sector of the Southern Ocean). We observed seasonal patterns in the abundance of prokaryotic transporters of seven trace elements (zinc [Zn], manganese [Mn], nickel [Ni], molybdenum [Mo], tungsten [W], copper [Cu] and cobalt [Co]) and the consecutive spring and summer phytoplankton blooms were strong drivers of these temporal trends. Taxonomic affiliation of the functional genes revealed that Rhodobacteraceae had a broad repertoire of trace metal transporters (Mn, Zn, Ni, W and Mo) and a more restricted set was observed for other prokaryotic groups, such as Flavobacteriaceae (Zn), Nitrincolaceae (Ni and W) and Thioglobaceae (Mo). The prevalence of trace metal transporters within a prokaryotic group, as determined on the family level, was overall confirmed in representative metagenome‐assembled genomes. We discuss the potential involvement of prokaryotic groups in processes related to organic matter utilisation that require these metals and the consequences on carbon and trace metal cycling in surface waters of the Southern Ocean. [ABSTRACT FROM AUTHOR]

In this study, molecular dynamics (MD) simulations were used to investigate how alloying tungsten (W) with molybdenum (Mo) and local strain affect the primary defect formation and interstitial dislocation loops (IDLs) in W–Mo alloys. While the number of Frenkel pairs (FPs) in the W–Mo alloy is similar to pure W, it is half that of pure Mo. The W–20% Mo alloy, chosen for further analysis, showed minimal FP variance after collision cascades induced by primary knock-on atoms (PKAs) at 10 to 80 keV. The research examined hydrostatic strains from −1.4% to 1.6%, finding that higher strains correlated with increased FP counts and cluster formation, including IDLs. The following two types of IDLs were identified: majority ½ <111> loops as well as <100> IDLs that formed within the initial picoseconds of the simulations under higher tensile strain (1.6%) and larger PKA energies (80 keV). The strain effects also correlated with changes in threshold displacement energy (TDE), with higher FP formation under tensile strain. This study highlights the impact of strain and alloying on radiation damage, particularly in low-temperature, high-energy environments. [ABSTRACT FROM AUTHOR]

The Shepherd and Murphy Mine in northwestern Tasmania was a tin, tungsten, and bismuth mine that operated from 1892 to 1957. Despite challenges such as poor transport infrastructure and complex ores, the mine achieved longevity through adaptation to wartime demands for tungsten. The village of Moina, where the mine was located, was a company town with streets named after mining company directors. The mine experienced periods of decline and closure but was briefly revived during the Korean War. Today, the area has been explored for other resources but no viable deposits have been found, and the village of Moina is now home to hobby farmers and commuters. The mine's history and its connection to the battlefields of Europe and the Korean Peninsula have been largely overlooked. [Extracted from the article]

This paper presents new isotopic, geochemical, and geochronological data on granitoids of the southeastern Voznesenka terrane of the Khanka block of the Amur paleocontinent. These granitoids are assumed to be a source of gold and tungsten mineralization in the host Late Paleozoic and Early Mesozoic strata and were initially considered to be of Late Cretaceous age. However, according to U-Pb isotopic data on zircons, their age is Middle Permian (~267 ± 3 Ma), which contradicts the idea of them being an ore-generating system that triggered the formation of mineralized zones in the associated younger volcanosedimentary and terrigenous formations of the Middle–Late Permian and Triassic age, respectively. [ABSTRACT FROM AUTHOR]

Minor amounts of tungsten (W) are well known to improve Ni‐rich layered oxide‐based cathode active materials (CAMs) for Li ion batteries. Herein, W impacts are validated and compared for varied concentrations and incorporation routes in aqueous media for LiNi0.90Co0.06Mn0.04O2 (NCM90‐6‐4), either via modification of a precursor NixCoyMnz(OH)2 (pCAM) within a sol–gel reaction or directly during synthesis, i.e., either via an W‐based educt or during co‐precipitation in a continuously operated Couette–Taylor reactor. In particular, the sol–gel modification is shown to be beneficial and reveals >500 cycles for ≈80% state‐of‐health NCM90‐6‐4||graphite cells. It can be related to homogeneously W‐modified surface as well as smaller and elongated primary particles, whereas the latter are suggested to better compensate anisotropic lattice stress and decrease amount of microcracks, consequently minimizing further rise in surface area and the accompanied failure cascades (e.g., phase changes, metal dissolution, and crosstalk). Moreover, the different incorporation routes are shown to reveal different outcomes and demonstrate the complexity and sensitivity of W incorporation. [ABSTRACT FROM AUTHOR]

Glow discharges are known to be limited for running at high current densities (typically below 0.1 A ⋅ c m − 2 ). Magnetically enhanced plasmas overcome this limitation, reaching up to two orders of magnitude higher current densities. However, the highest reported discharge current density hardly reaches 10 A ⋅ c m − 2 even in high power impulse magnetron sputtering (HiPIMS). Here, we report on the long (∼1 ms) pulsed operation of the magnetron in helium with an over-dense current (∼30 A ⋅ c m − 2 , usual for arcs) while preserving the glow mode. This regime defying the arcs was called hyper power impulse magnetron (HyPIM) because the power injected per pulse is several times higher than in HiPIMS for the same average power and pulse duration. HyPIM operation mode is distinguished from HiPIMS by the limited pulse voltage and is unsuitable for thin film deposition but may interest plasma switches. These huge currents were obtained for two cathode materials, molybdenum (Mo) and tungsten (W). Different experimental diagnostics bring insights into the physical phenomena governing the HyPIM plasma. A discussion on the role played by the metal atoms on the current unveils the origin of such exceptional glow current all along the pulse and the key role of the helium metastable atoms. A schematic of the kinetic steps of the HyPIM discharge is proposed. [ABSTRACT FROM AUTHOR]

The study is devoted to enhanced CeO2 evaporation in the temperature range between 2130 and 2650 K from refractory crucibles made of different materials: molybdenum, tantalum, and tungsten. The composition datum of vapor and films deposited on collectors receiving evaporation products were obtained by quadrupole mass spectroscopy and by energy-dispersive X-ray spectroscopy. One of approximation coefficients of the temperature dependence of CeO2 vapor in the range between 2150 and 2220 K was measured. The study is of interest for a variety of technologies utilizing refractory oxide evaporation with high productivity, including the plasma mass separation methods. [ABSTRACT FROM AUTHOR]

The configurations, electronic attributes and dipole magnitudes of the TMWn–1O3n (TM = Mn, Fe and Co, n = 2 ~ 6) clusters have been calculated by using first–principles. The TM substitution significantly reduces the thermodynamic stability of tungsten oxide clusters. The position of tungsten atom substituted for the MnW4O15 clusters is different from those for the TMW4O15 (TM = Fe and Co) clusters. The MnW3O12, MnW5O18, FeWO6 and FeW5O18 clusters exhibit more kinetically stable than their neighbors. The charge transfer amounts (1.066 |e|, 1.104 |e|, 1.094 |e|, 1.138 |e| and 1.137 |e|) of the MnWn–1O3n clusters are more than those of the TMWn–1O3n (TM = F e and Co) clusters. Dipole magnitudes (1.6972 Debye, 1.342 Debye and 1.5261 Debye) of the MnW4O15, FeW3O12 and CoW3O12 clusters are larger than neighboring TMWn–1O3n clusters. [ABSTRACT FROM AUTHOR]

In this paper, experimental analysis was performed during micro-electrical discharge machining (micro-EDM) of titanium alloy Ti–6Al–4V (grade 5) using three types of tools viz. copper (Cu) tool, tungsten carbide (WC) tool, and synthetic graphite (Gr) grade three tool. The main process parameters were taken as (a) pulse on time ( T on ), (b) pulse off time ( T off ), (c) voltage (V), and (d) capacitance (C). The output responses were taken as the material removal rate (MRR) and tool wear rate (TWR). Taguchi method coupled with grey relational analysis (GRA) (L 1 6 orthogonal array) technique was applied to optimize the input process parameters for both the responses. Scanning electron microscopy (SEM) analysis of the workpiece and tool was also performed to investigate the morphology of the machined surface and tool surface. Energy-dispersive spectroscopy (EDS) analysis was performed to investigate the elemental composition of the machined surface. The experimental finding reveals that tungsten carbide is the most suitable tool material for machining the chosen workpiece for obtaining optimal MRR and TWR. The optimum condition for the copper tool was found as 180 V, 1000 pf, 10 μ s ( T on ), and 10 μ s ( T off ). Meanwhile, the optimum parametric condition for tungsten carbide and graphite tools was found to be the same as 240 V, 100 pf, 20 μ s ( T on ), and 5 μ s ( T off ). [ABSTRACT FROM AUTHOR]

A novel integrated strategy is proposed to construct the LiNi 0.9 Co 0.09 W 0.01 O 2 with simultaneous spinel phase and Li 2 TiO 3 conductive network, which can enhance the lithium-ion migration kinetics and structural stability of ultrahigh-Ni cathode materials. [Display omitted] The tungsten with high oxidation states (W6+) had been proved to effectively improve the electrochemical performance of ultrahigh-nickel (Ni ≥ 90 %) cathode materials due to the unique microstructures. However, the exat location and underlying action mechanism of tungsten are still not well-understood, and there have been no reports on in-situ modification from bulk to surface simultaneously for these novel cathode materials. Here, a novel integrated strategy is proposed for in-situ modification of LiNi 0.9 Co 0.09 W 0.01 O 2 (NCW). Innovatively, the introduction of nano spinel phase and titanium pinned into the lattice further suppresses the anisotropic variation of unit cell and promotes the lithium-ion migration kinetics within the bulk. Additionally, the Li 2 TiO 3 conductive network enhances migration kinetics across interface and protects the active material against electrolyte erosion. Furthermore, the combination of in-situ analysis and DFT calculation reveals the ordered distribution of tungsten and the suppression effects of titanium on phase transition and cobalt redox. Consequently, the titanium-modified NCW exhibits significantly improved electrochemical performance, such as capacity retention of 93.0 % at 1C after 500 cycles in pouch-type full-cell, along with stable lattice oxygen during operation. [ABSTRACT FROM AUTHOR]

First - principles calculations were conducted to investigate the changes in mechanical and thermal properties of tungsten/graphene/tungsten composites, and the performance attenuation under plasma irradiation was evaluated via simulated irradiation damage by helium - vacancy associative defect. The calculation results show that the bulk modulus, Young's modulus and shear modulus of the tungsten/graphene/tungsten composites decrease to a certain extent, but the ductility is improved. The tungsten/graphene/tungsten composites increase thermal expansion coefficient at high temperatures compared with pure tungsten, but have a higher minimum thermal conductivity. The unique mechanism by the graphene interface layer can absorb impurities and defects in the matrix, which can result in tungsten/graphene/tungsten composite has smaller attenuation in mechanics, thermal expansion coefficient and minimum thermal conductivity. This shows the potential of tungsten/graphene/ tungsten composites in radiation resistance. [ABSTRACT FROM AUTHOR]

The evaluation of the impact of plasma-facing units (PFUs) damage on subsequent plasma operation is an important issue for ITER. This is one of the topic addressed by the operation of dedicated PFUs in WEST. From the start of WEST in 2017, few ITER grade divertor PFUs were tested in the lower divertor for short plasma exposure (experimental campaigns C1–C5). A PFU is an assembly of tungsten blocks on CuCrZr tube via pure copper interlayer. Since 2022, WEST operates with a lower divertor fully equipped with ITER grade PFUs (experimental campaign C6–C7) with long duration plasma exposure capabilities. To test the ageing of the ITER-grade PFUs on an accelerated basis, well controlled damage was implemented on purpose with electron beam loading on the plasma facing surface of two different PFUs (pre-damage#1 and #2 featuring different level of damage). Damage tackled in this study is induced by the loading with numerous transient heat loading events to mimic the ELM impact on the ITER grade PFU. This paper presents the damage before and after WEST plasma exposure and shows the tungsten sources and temperature of the block measured during the operation. On damaged area, surface roughening is heterogeneous. With WEST campaigns (C3, C4 and C7) respectively ended in (2018, 2019 and 2023) a global smoothing of the pre-damaged surfaces, in particular those located in the high loaded erosion area, is observed. No evolution of the crack is observed in the electron beam loaded area, while new cracking are observed on non pre-damaged area on the tungsten top surfaces in highly loaded areas (outer strike point) after significant plasma duration and cumulated energy (first observation in C4 and tends to be confirmed with preliminary observations after the C7 campaign). Smoothing is less pronounced after the 2018 campaign, which may be due to the related short plasma duration. The surface smoothing of blocks also depends on their poloidal position. For PFU which has no shaping, toroidal positioning within a block has no influence on the surface smoothing. After 2019 and 2023 campaigns, equivalent relative smoothing is obtained (between 19 and 32%). For the explored plasma conditions, damage has no influence on the maximum brightness of W. [ABSTRACT FROM AUTHOR]

New data are presented on the formation conditions and ages of the reduced intrusion-related Au mineralization of the Vetrenskaya area in the Central Kolyma region. The mineralization is predominantly confined to intersections of Late Jurassic minor intrusive bodies and NE-trending fracture systems and is represented by zones of thin quartz veinlets with sericite–quartz halos. The major ore mineral is gold-bearing arsenopyrite (up to 10%), while minor minerals are represented by lellingite, pyrite, chalcopyrite, and pyrrhotite. Microscopic native gold of a low fineness is paragenetically associated with bismuth minerals (bismuthine, native bismuth, and tellurides of Bi and Au), forming microinclusions (1–10 μm) in the arsenopyrite. The isochronous Re–Os age of the goldbearing arsenopyrite is 137–117 Ma, which suggests the mineralization was formed significantly later than the hosting granitoids (147–153 Ma). The reduced intrusion-related Au ore deposit was formed at shallower depths than orogenic Au deposits were and at lower temperatures in comparison with rare-metal (W, Mo) ore deposits. [ABSTRACT FROM AUTHOR]

New materials for oxygen evolution reaction (OER) electrocatalysts in alkaline conditions have been highly investigated in recent years for the advancement of water splitting. However, questions such as the lack of stability and the use of noble metals as electrocatalysts still need to be addressed. In this study, we report the synthesis and electrocatalytic properties of a series of wolframite tungsten‐based materials (MWO4, M=Fe, Mn, Ni, Co) towards OER in basic conditions. Our results showed that Ni0.5Mn0.5WO4 is a promising electrocatalyst, exhibiting ease of preparation, stability over the course of our experiments, and OER activity comparable to the standard iridium oxide. This study highlights the potential of wolframite tungsten‐based materials as a new class of electrocatalysts for OER in alkaline conditions. [ABSTRACT FROM AUTHOR]

Because of the complex composition of tungsten tailings and low tin content in the tailings, the traditional titration analysis method and colorimetric analysis method are easily interfered by tungsten, copper and other elements, resulting in unsatisfactory results. In this paper, sodium peroxide was used to melt tungsten tailings sample, water leaching, hydroxide precipitation separation of most of the interference elements, supernatant liquid acidification, atomic fluorescence spectrometry was used for determination, which solved the problem of insufficient sensitivity, eliminated the influence of coexisting tungsten, copper and other elements on the determination of tin, and established the accurate determination of tin in tungsten tailings by atonic fluorescence spectrometry. At the same time, the influences of sample treatment method, determination of solution acidity, thiourea-ascorbic acid mixed reducing agent and potassium borohydride concentration on the determination of tin by atonic fluorescence spectrometry were investigated, and the determination parameters of atomic fluorescence spectrometry were optimized. The relative standard deviation (RSD, n = 7) of the determination of tin was less than 5%. The tungsten ore composition analysis standard substance with tungsten content similar to that in tungsten tailings was used for method verification. The absolute value of the relative error was LESS than 5%, and the recovery rate was 94.5%-108%. This method for determining in in tungsten tailings has the advantages of simple operation, high sensitivity, less interference, high accuracy and low cost. [ABSTRACT FROM AUTHOR]

Address to poor adaptability of traditional smelting methods to raw materials like bismuth concentrate, especially unsuitable for low-grade bismuth concentrate, low comprehensive recovery rate of valuable metals, difficult treatment of low concentration SO2 produced by pyrometallurgy, and high cost, a new process for separating molybdenum, tungsten, sulfur and bismuth by pressure oxidation alkaline leaching was proposed using low grade bismuth polymetallic concentrate of Shizhuyuan as raw material. The effects of alkali dosage, time, temperature, total pressure and liquid-solid ratio on the leaching rate of molybdenum, tungsten, sulfur and bismuth were studied. Under the optimum conditions, the leaching rate of molybdenum, tungsten and sulfur is 99.73%, 90.81% and 97.69% respectively, while bismuth remains un-leached and is enriched in the slag, which realizes the efficient separation of molybdenum, tungsten, sulfur and bismuth in low-grade bismuth polymetallic concentrates. [ABSTRACT FROM AUTHOR]

Tungsten (W) and tungsten alloys are being considered as leading candidates for structural and functional materials in future fusion energy devices. The most attractive properties of tungsten for the design of magnetic and inertial fusion energy reactors are its high melting point, high thermal conductivity, low sputtering yield, and low long-term disposal radioactive footprint. Despite these relevant features, there is a lack of understanding of how the structural and mechanical properties of W-based alloys are affected by the temperature in fusion power plants. In this work, we present a study on the thermo-mechanical properties of five W-based plasma-facing materials. First-principles density functional theory (DFT) calculations are combined with the quasi-harmonic approximation (QHA) theory to investigate the electronic, structural, mechanical, and thermal properties of these W-based alloys as a function of temperature. The coefficient of thermal expansion, temperature-dependent elastic constants, and several elastic parameters, including bulk and Young's modulus, are calculated. Our work advances the understanding of the structural and thermo-mechanical behavior of W-based materials, thus providing insights into the design and selection of candidate plasma-facing materials in fusion energy devices. [ABSTRACT FROM AUTHOR]

Tungsten-based scandate dispenser cathodes are promising next-generation thermionic electron sources for vacuum electron devices, due to their excellent emission performance at temperatures lower than those required for conventional cathodes. There has been a significant recent effort to understand scandate cathode performance and to characterize the tungsten and other materials on the emitting surface, primarily via the study of cathodes before and after emission testing. Moreover, these scandate cathodes have typically been characterized at room temperature only. In situ observations of scandate cathodes is challenging, as these devices are thermionic emitters that operate in a high-vacuum environment, and because the sizes of relevant material features range from the micron (2.0 µm) to the nanometer (<50 nm diameter) length scales. In the current study, a series of in situ heating experiments was conducted on un-activated impregnated scandate cathode fragments, utilizing a micro-electro-mechanical system-based heater chip in a scanning electron microscope, enabling the real-time observation of cathode material evolution at elevated temperature (up to 1200 °C) under a pressure of 10−6 to 10−7 mbar. This study revealed how impregnant materials grow and migrate within the cathode matrix at elevated temperatures, and these observations are key to a thorough understanding of the behavior of scandate cathode materials. It also enabled direct observation of the incipient faceting of tungsten surfaces at high temperature while surrounded by impregnant materials. These are the first in situ observations of scandate cathode material evolution in relevant environmental conditions and at sufficiently high resolution to provide insights into the morphological and phase changes that occur in the near-surface regions of scandate cathodes. [ABSTRACT FROM AUTHOR]

In this study, dynamic mechanical response and the corresponding atomic mechanisms of single-crystal tungsten under extreme strain rates (109 s−1) are investigated using molecular dynamics simulations. The results show that crystal orientation plays an important role in the stress–strain relationship. The critical stresses for the beginning of plastic deformation are 59.4, 48.0, and 25.2 GPa for quasi-isentropic tensile loading along [111], [110], and [100] crystal orientations, respectively. The atomic behavior during plastic deformation suggests that [100] and [110] experience stress relaxation through phase transitions, while not in the [111] tensile direction. During spallation, sub-grain boundaries formed at twin junction in the [100] and [110] directions serve as nucleation sites for voids. The void grows in a planar way (along the twin) after generation, while stops growing at another misoriented twin junction. In the [111] tensile test, spallation occurs in the stress-concentration area, and finishes in a very short time interval with huge void coalescence. Our findings not only provide atomic insights into the anisotropic mechanical behaviors during spallation of tungsten under high strain rates, but also shed lights on the colorful plastic deformation behaviors from laser-shock experimental observation. [ABSTRACT FROM AUTHOR]

Introduction: The utilization of metal shields in intensity-modulated brachytherapy (IMBT) enables the modulation of the dose, resulting in improved conformance to the tumor while simultaneously reducing the doses to organs at risk (OARs). Utilizing higher-energy sources like 60Co in IMBT for cervical and vaginal cancers has consistently posed challenges. This study evaluates the dosimetric aspects of modified applicators designed for IMBT using 60Co and 192Ir sources. Materials and Methods: GATE, a Geant4-based simulation code, was utilized to model and simulate four distinct applicators. The clinical applicators were redesigned to place the structure of the source tube and the shield while keeping the general characteristics unchanged. These shields were evaluated by calculating transmission factors (TFs) and the dose homogeneities were also determined. Result: Transmission factors for the IMBT technique in redesigned intrauterine applicators and tungsten shields for iridium and cobalt sources were at least 12.8 and 65.4%, and these values were obtained for the intravaginal applicator at 0.2 and 7.0%, respectively. The dose homogeneities for all combinations of radionuclide-shield were within a 15% range of the non-IMBT applicators. Conclusion: This study has quantitatively evaluated the dosimetric effect of tungsten shields in the IMBT technique for cervical and vaginal cancer using cobalt sources. 192Ir compared to 60Co resulted in higher effectiveness for the designed intrauterine and intravaginal shields. while implementing tungsten shields in the redesigned applicators against the 60Co source may not offer complete protection, it does show promising results in reducing the dose to organs at risk. [ABSTRACT FROM AUTHOR]

Complex oxides Eu2MeO6 (Me–Mo, W), Eu2W2O9 were obtained by a solid‐phase reaction between binary oxides. The thermodynamic and kinetic mechanisms of the reaction processes were established using a variety of physical‐chemical methods. All compounds obtained in this work crystallize in the low‐symmetry monoclinic system, forming complex framework structures, which determine a set of very valuable physical‐chemical properties. Comparison of experimental Kubelka‐Munk functions and DFT‐ calculated absorption spectra shows adequate agreement and reveals the origin of the fundamental absorption. In addition, the deficiency in DFT calculations in the part of mutual contribution of CTBs of Mo−O and W−O, from one side, and Eu−O contributions, from the other side, is reported. Calculations of absorption spectra are shown to be superior to band structure analysis in the determination of optical band gaps. Additionally, luminescent properties of Eu2MeO6 and Eu2W2O9 compounds were investigated. These studies provide a better understanding of the electronic and optical properties of the compounds Eu2MeO6 and Eu2W2O9, along with their potential applications in various areas. [ABSTRACT FROM AUTHOR]

Dual-band electrochromic windows have emerged as a promising approach to reduce building energy consumption. However, developing facile and effective method for preparing single-component dual-band electrochromic material remains a challenge. Herein, an in situ carbothermal reduction strategy was utilized to fabricate monoclinic oxygen-deficient tungsten oxide (WO 3-x) for high-performance dual-band electrochromism. Polyvinylpyrrolidone (PVP–K90) underwent transformation into amorphous carbon at high temperature, serving as the reducing agent embedded in the tungsten oxide film, and in situ inducing the formation of oxygen vacancies during annealing treatment. Lastly, the amorphous carbon was gasified without weakening the transmittance of WO 3-x film. The content of oxygen vacancies in WO 3-x could be modulated by controlling the added amount of PVP-K90. The intrinsic generation of oxygen vacancies not only obtained a strong local surface plasmon resonance (LSPR) absorption in near-infrared (NIR) range, but also improved lithium ion (Li+) diffusion in WO 3-x film. The WO 3-x electrochromic film exhibited excellent dual-band electrochromic performance in optical modulation, switching time, coloring efficiency, bistability, and cycle stability. Furthermore, the WO 3-x film was applied to electrochromic window to verify its available regulation in solar illumination and heat, indicating that the designed modification strategy has potential for developing a single-component dual-band electrochromic window with outstanding performance. [ABSTRACT FROM AUTHOR]

The paper presents the results of studying the structure and phase state of tungsten and tungsten-copper alloy after pulsed action of compression plasma flows and irradiation with helium ions. The compression plasma flows were used to modify the surface layer of tungsten, as well as to create an alloy based on tungsten and copper. Using scanning electron microscopy and X-ray structural analysis, the formation of radiation defects on the tungsten surface was detected in the form of local areas of exfoliation and destruction, which begin to form at helium ion irradiation doses of 2 × 1017 cm−2. It is shown that preliminary plasma treatment of the surface in the melting mode leads to the complete disappearance of surface radiation defects up to a dose of 2 × 1017 cm−2, which may be associated with the formation of a fine-crystalline grain structure, the intergranular boundaries of which serve as effective sinks for primary radiation defects. [ABSTRACT FROM AUTHOR]

Herein, a new heterojunction photovoltaic (PV) device is designed by incorporating molybdenum trioxide (MoO3) as a hole transport layer (HTL), tin sulfide (SnS) as an absorber, and tungsten disulfide (WS2) as an electron transport layer (ETL). The PV outputs of the proposed thin‐film solar cell (TFSC) of Ni/MoO3/SnS/WS2/FTO/Al are investigated using the widely used solar cell simulator (SCAPS‐1D). It is found that the SnS TFSC with suitable band alignments at both the SnS/WS2 and MoO3/SnS interfaces gives better photoconversion efficiency than the conventional one. To optimize the material properties, the performance parameters, including open‐circuit voltage (Voc), short‐circuit current density (Jsc), fill factor (FF), and efficiency, have been calculated by varying the influences of the material's thickness, doping concentration, bulk and interface defect densities, operational temperature, and work function of back‐contact. At optimized thicknesses of 0.1 μm for MoO3 HTL and 1.0 μm for SnS absorber, the efficiency is estimated to be 30.42% with Voc of 1.02 V, Jsc of 34.38 mA cm−2, and FF of 87.04% for the suggested TFSC. These outcomes imply that the nontoxic MoO3 and WS2 materials can be applied as HTL and ETL into the inexpensive, highly efficient, and environmentally friendly SnS‐based PV cell. [ABSTRACT FROM AUTHOR]

Tungsten phosphide (WP) nanoparticles supported on nitrogen and phosphorus co-doped carbon nanosheets (WP@NPC) provide outstanding performance as a multifunctional separator in lithium-sulfur batteries, enabling higher sulfur utilization and exceptional rate capability. Its excellent performance is associated with the abundance of lithium polysulfide (LiPS) adsorption and catalytic conversion sites and swift ion transport within the separator. Key to these features is the sulfophilic character of W and the lithiophilicity of nitrogen and phosphorus, as well as the capability of WP to regulate the LiPS catalytic conversion, accelerating the Li-S redox kinetics. [Display omitted] Lithium-sulfur batteries (LSBs) hold great potential as future energy storage technology, but their widespread application is hampered by the slow polysulfide conversion kinetics and the sulfur loss during cycling. In this study, we detail a one-step approach to growing tungsten phosphide (WP) nanoparticles on the surface of nitrogen and phosphorus co-doped carbon nanosheets (WP@NPC). We further demonstrate that this material provides outstanding performance as a multifunctional separator in LSBs, enabling higher sulfur utilization and exceptional rate performance. These excellent properties are associated with the abundance of lithium polysulfide (LiPS) adsorption and catalytic conversion sites and rapid ion transport capabilities. Experimental data and density functional theory calculations demonstrate tungsten to have a sulfophilic character while nitrogen and phosphorus provide lithiophilic sites that prevent the loss of LiPSs. Furthermore, WP regulates the LiPS catalytic conversion, accelerating the Li-S redox kinetics. As a result, LSBs containing a polypropylene separator coated with a WP@NPC layer show capacities close to 1500 mAh/g at 0.1C and coulombic efficiencies above 99.5 % at 3C. Batteries with high sulfur loading, 4.9 mg cm−2, are further produced to validate their superior cycling stability. Overall, this work demonstrates the use of multifunctional separators as an effective strategy to promote LSB performance. [ABSTRACT FROM AUTHOR]

The reaction of N‐(4‐methyl‐2‐pyridinyl)‐P,P‐diphenylphosphinous amide ligand 4‐Me‐C5H3N‐2‐NH(PPh2) (1) with M(CO)6 (M=Cr, Mo, W) in refluxing toluene afforded a mononuclear group VIB metal tetracarbonyls [M(CO)4{1‐κ2P,N}] (M=Cr(2), Mo(3), W(4)). Complexes 2–4 were characterized by multinuclear NMR (1H, 13C and 31P NMR) and IR spectroscopy, and their structures were also determined by single crystal X‐ray diffraction. 2 and 4 represent the first examples of structurally characterized complexes of such ligands with group 6B metal carbonyls. [ABSTRACT FROM AUTHOR]

The atmospheric pressure plasma source HelixJet has been used to generate tungsten nanocrystals with narrow size distributions, well defined size control and with a considerably good particle yield. Tungsten particles are produced as the result of an evaporation process of a tungsten wire inserted on the middle axis of the jet after the wire is heated by interaction with the plasma. Temperature measurements using a thermocouple and by optical emission spectroscopy showed that, while the overall temperature of the wire is very high, it is not in the range of the melting temperature of tungsten; however, it can reach values needed for sublimation. Additionally, the wire is heated selectively while the temperature of the jet components reaches only a few hundred degrees Celsius. The particles cluster into agglomerates and their formation has been analyzed in relation to the reliability of a commercial scanning mobility particle sizer spectrometer. The dependence of the particle morphology and crystal structure on the plasma parameters such as power and gas flow was studied via transmission electron microscopy and the average size of the tungsten nanocrystals could be tuned between 12 and 25 nm. [ABSTRACT FROM AUTHOR]