Series new Ba(4)RETiNb(9)O(30) (RE = La, Pr, Nd, Sm, Eu, Gd) compounds and ceramics were prepared by solid state reaction method respectively. The phase structure, microstructure, dielectric and ...ferroelectric properties of obtained ceramics were systematically investigated. The XRD results show that all ceramics have been determined as pure tungsten bronze phase. The dielectric characterization indicates that the former four ceramics are relaxors with strong diffuse phase transition and frequency dispersion, while the latter two ceramics show diffuse phase transition. Phase transition temperatures and tetragonality of tungsten bronze structure increase with the decrease of the radii of rare earth. All ceramics have ferroelectricity, among them Ba(4)GdTiNb(9)O(30) has the highest remnant polarization (2P(r)) of 5.12 muC/cm(2).
Structural and compositional changes of Cs‐doped hexagonal tungsten bronzes (HTB) with respect to variations in oxygen deficiency and alkali content have been investigated in detail through x‐ray ...diffraction Rietveld analysis, x‐ray photoelectron spectroscopy, and Raman spectroscopy. Cs‐HTB crystallized in a reductive atmosphere is evidenced to generally contain plenty of oxygen defects, and a general formula, CsxWO3−y (0.20 ≤ x ≤ 0.32, 0 < y ≤ 0.46), is proposed. Lattice parameters of Cs‐HTB are observed to vary according to the relation, c (Å) = −3.436a (Å) + 33.062. The coordinated modification of W–O octahedral dimensions suggests the origin of the structural change with increasing x and y to be a destabilization of the pseudo Jahn‐Teller distortion due to donated electrons. The dimensional change of lattice due to electrons emitted from oxygen defects is appraised only 1/18 as that due to electrons from doped alkali ions, suggesting that most electrons from oxygen defects should be localized in Cs‐HTB.
Specimens cut from a rolled tin bronze sheet were annealed at 400–800°C for 1h and evolution of their microstructures was then characterized in details by electron channeling contrast imaging and ...electron backscatter diffraction techniques. Particularly, statistics on special boundaries (SBs) with Σ≤29 and network connectivity of random high angle boundaries (HABs) in the annealed specimens were examined to probe optimization potentials of grain boundary character distribution (GBCD) for this material. Results show that the deformed microstructure in the as-received material begins to be recrystallized when the annealing temperature increase to 500°C and average grain sizes surge with further increasing temperatures. As a result of the recrystallization, a large number of annealing twins (with Σ3 misorientation) are produced, leading to remarkably increased fractions of SBs (fSBs). Thanks to preexisting dense low angle boundaries, the majority of SBs in the 500°C specimen with only partial recrystallization are Σ3ic (incoherent) boundaries, which effectively disrupt connectivity of random HABs network. Although the fSBs can be further increased (up to 72.5%) in specimens with full recrystallization (at higher temperatures), the Σ3ic boundaries would be replaced to some extent by Σ3c (coherent) boundaries which do not contribute directly to optimizing the GBCD. This work should be able to provide clear suggestions on applying the concept of grain boundary engineering to tin bronze alloys.
•The rolled tin bronze begins to be recrystallized as temperature increases to 500°C.•A lot of SBs are produced after recrystallization and the highest fSBs is 72.5%.•Partially recrystallized specimen has the optimum GBCD due to more Σ3ic boundaries.•The Σ3ic boundaries are replaced by Σ3c boundaries after full recrystallization.
In his pioneering study, Men in Metal, Sven Saaler examines Japanese public statuary as a central site of historical memory from its beginnings in the Meiji period through the twenty-first century. ...Saaler shows how the elites of the modern Japanese nation-state went about constructing an iconography of national heroes to serve their agenda of instilling national (and nationalist) thinking into the masses. Based on a wide range of hitherto untapped primary sources, Saaler combines data-driven quantitative analysis and in-depth case studies to identify the categories and historical figures that dominated public space. Men in Metal also explores the agents behind this visualized form of the politics of memory and introduces historiographical controversies surrounding statue-building in modern Japan.
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•Protectiveness of organosilane coating (PropS-SH) on patinated bronze was assessed.•Patina of cuprous oxide and sulphide does not protect the bronze against corrosion.•Both sprayed ...PropS-SH and Incralac® offer a good protection to patinated bronze.•PropS-SH shows excellent performance under UV light and simulated outdoor exposure.•Higher wettability of PropS-SH favours its penetration in porous patina structure.
A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by “liver of sulphur”, was investigated as a non-toxic alternative to Incralac®, usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and accelerated corrosion test simulating unsheltered exposure to rainwater was also carried out. The exposed samples were characterised by FEG-SEM coupled with EDS on FIB cross-sections and XPS on free surfaces. The black patina without protective coating was scarcely protective against bronze corrosion and easily transformed into cuprous oxide. PropS-SH coating fully preserved the black patina microstructure and phase constituents (cuprous oxide and cuprous sulphide). The PropS-SH coating also resulted more protective than Incralac® when aged under run-off conditions. Selective dissolution of copper from the silicon bronze alloy was observed on both uncoated and Incralac®-coated bronze, leading to the formation of an internal Si-rich corrosion layer.
From an energy-saving perspective, solar heat shielding materials for architectural or automobile glass have become more and more important for sustainable development, which has attracted global ...attention. The solar heat shielding materials need to meet the requirements of high visible transmittance, strong near infrared absorption, low cost and easy process. Nanostructured rare-earth hexaborides and tungsten bronzes are new kinds of promising heat shielding materials with excellent properties. This review presents a brief introduction on the recent progress in these two kinds of materials. Systematic work including the synthesis, characterization and optical response of nanocrystalline rare-earth hexaborides and tungsten bronzes are summarized. Especially the theoretical explanations of the mechanism of optical properties, tunable characteristic of optical properties, influence of particle size and shape on its optical response are reviewed in this document. Finally, we offer some suggestions for further investigation on these nanostructures, including efficient preparation methods considering environmental and economic costs for obtain morphology and size controllable samples; preventing agglomeration of the final products; some problems to be solved for commercial application. The review can provide a quick reference and overview for heat shielding materials and smart window industry.
Aluminium bronzes are widely used in various industries because of their unique properties, a combination of high strength, wear resistance, and corrosion resistance in aggressive environments, ...including seawater. In this study, the subject of comprehensive experimental research was Cu-10Al-5Fe iron-aluminium bronze (IAB) with β-transformation, received in the form of hot-rolled bars. The effects of different heat treatments (HT) and severe surface plastic deformation (SPD), conducted by diamond burnishing (DB) on the microstructure, surface integrity (SI), mechanical properties, low- and mega-cycle fatigue strength, and dry sliding wear resistance, were determined. Based on quantitative indicators, the applied heat treatments in combination with severe SPD were compared. Thus, the integral efficiency of the heat treatments was evaluated, and the heat treatments were correlated with the resulting properties and operational behaviour of Cu-10Al-5Fe IAB. For example, if the component is designed for rotational bending conditions, the combination of quenching at 920 °C in water, subsequent tempering at 300 °C for three hours, and DB provides maximum fatigue strength in both low-cycle and mega-cycle fatigue applications.
Ultrasound (US)‐mediated sonodynamic therapy (SDT) has the advantages of non‐invasiveness and deep tissue penetration. Nanosystems are prominently used in sonosensitization; however, most ...nano‐sonosensitizers have a low reactive oxygen species (ROS) yield, thus restraining the application of SDT. Sodium molybdenum bronze nanoparticles (SMB NPs) with rich oxygen vacancies are developed and interlayer gaps of molybdenum trioxide nanobelts are expanded. Owing to the increased oxygen vacancy density and wide interlayer gap‐induced narrower band gap of SMB NPs, the electrons (e–) and holes (h+) generated by US are separated more rapidly, and oxygen vacancies prevent electrons–holes recombination under US irradiation. SMB NPs exhibit a second near‐infrared (NIR‐II) photothermal effect to promote the generation of ROS by the sonosensitizer. The SMB NPs system is successfully realized to eliminate Staphylococcus aureus (S. aureus) and dissipate biofilm. Therefore, multimodal therapy using SMB NPs serves as an effective and promising regimen for deep‐seated bacterial infections. The newly developed Mo‐based sonosensitizer is presented for the first time to demonstrate excellent antimicrobial activity through hyperthermia‐promoting SDT therapeutics. This work proposes a novel strategy in the field of NIR‐II photo‐amplified SDT with Mo‐based materials for bacterial eradication and other important biomedical applications.
The newly developed Mo‐based sonosensitizer is presented for the first time to demonstrate excellent eradicate bacteria in deep‐seated infected tissues in vivo through photothermal‐amplified sonodynamic therapy (SDT) to accelerate abscess healing, which can open a new window in the field of NIR‐II photo‐amplified SDT with Mo‐based materials for bacterial eradication and other biomedical applications.
A surface process electropulsing-assisted ultrasonic surface rolling process (EP-USRP) has been used to treat nickel aluminum bronzes (NAB). Surface quality, hardness and corrosion resistance were ...evaluated to analyze the surface resistance to cavitation corrosion. The surface roughness was reduced from turning Ra 0.733 μm to EP-USRP Ra 0.050 μm, eliminating the surface turning furrow and improving the surface quality. The surface hardness of the sample treated by EP-USRP at 15 V was increased from 160 HV to 267 HV, and a hardness gradient layer of more than 1000 μm was obtained, thereby improving the surface strength. As the electric pulse which promotes the proliferation and movement of dislocations, the surface strength increased first and then decreased. EP-USRP acts on the surface layer of the lamellar phases to deflect and shred, and tend to be parallel to the surface, which will change the crack propagation path, so that the cracks tend to expand parallel to the surface. Moreover, the samples treated by EP-USRP showed superior corrosion resistance than untreated ones. The surface weight loss of the samples after EP-USRP was greatly reduced compared with the turning surface. The EP-USRP makes NAB the greater surface quality, the stronger surface layer, the higher corrosion resistance and the deflection of lamellar phases is the main reason for the improvement of the surface cavitation corrosion resistance.
•Electropulsing improved cavitation corrosion resistance effectively.•Surface quality, corrosion resistance and mechanical property were enhanced.•Electropulsing bring different surface hardness under different parameters.•Cavitation corrosion cracks propagation parallel to surface.
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