Tungsten has been considered as one of suitable candidate as plasma-facing material for the first wall of fusion devices. However, the application of tungsten in fusion reactions presents risk ...because of the brittleness, high ductile–brittle transition temperature, and other defects of tungsten materials. Studies have shown that ultrafine-grained/nanostructured tungsten materials can improve these problems. In its first part this article describes the powder metallurgy techniques for the preparation of ultrafine-grained/nanostructured tungsten. And the second part of this article reviews bulk processes for the preparation. The possibility of preparing ultrafine-grained/nanostructured tungsten and referenceable process parameters are described. By describing the mechanical properties and irradiation performance of ultrafine-grained/nanostructured tungsten, the research prospects and development directions of tungsten materials for fusion reactors are indicated.
•Formation mechanism of the ultrafine-grained/nanostructured arrangements and their effects on the properties are reviewed.•Adding Ti played a positive role in improving the oxidation resistance of the alloy.•WCrY alloy has more excellent oxidation resistance than WCrTi ternary alloy.•WCrY alloy after annealing has better oxidation resistance.
We report a simple fabrication, great performance and cost-effective triboelectric nanogenerator (TENG), which is based on the cycled contact-separation between a polydimethylsiloxane (PDMS) film and ...a polyethylene terephthalate (PET) film, for effectively harvesting footfall energy. The elastic sponge is first used as the spacer in the TENG, where the size and the thickness of the spacers have a significant effect on the output performance of the TENG. By using the optimized device, a TENG-based shoe insole is used to harvest human walking energy, where the maximum output voltage and current density reached up to 220V and 40µA, respectively. We also demonstrate that the fabricated shoe insole using a single layer of TENG can be directly used to light up 30 white light-emitting diodes (LEDs) in serial connection. By taking the merits of this simple fabrication, outstanding performance, robust characteristic and low-cost technology, we believe that TENG can open up great opportunities not only for powering small electronics, but also can contribute to large-scale energy harvesting through engineering design.
By using the optimized device, a TENG-based shoe insole is used to harvest human walking energy, where the maximum output voltage and current density reached up to 220V and 40µA, respectively. We also demonstrate that the fabricated shoe insole using a single layer of TENG can be directly used to light up 30 white light-emitting diodes (LEDs) in serial connection. By taking the merits of this simple fabrication, outstanding performance, robust characteristic and low-cost technology, we believe that TENG can open up great opportunities not only for powering small electronics, but also can contribute to large-scale energy harvesting through engineering design. Display omitted
•We have fabricated a TENG, including a PDMS film and a PET film, based on the triboelectric effect.•Through optimization, a TENG with 4.5×4.5cm2 in size can generate up to 0.8μA/cm2 and 135V, respectively.•We demonstrate that the TENG-based shoe insole can instantly light up 30 LEDs simply with human stepping force.
A
bstract
We explored the gravity dual of a rotating quark-gluon plasma by transforming the boundary coordinates of the large black hole limit of Schwarchild-AdS
5
metric. The Euler-Lagrange equation ...of the Nambu-Goto action and its solution become more complex than those without rotation. For small angular velocity, we obtained an analytical form of the drag force acting on a quark moving in the direction of the rotation axis and found it stronger than that without rotation. We also calculated the heavy quark potential under the same approximation. For the quarkonium symmetric with respect to the rotation axis, the depth of the potential is reduced by the rotation. For the quarkonium oriented in parallel to the rotation axis, the binding force is weakened and the force range becomes longer. We also compared our holographic formulation with others in the literature.
Carbon dots inducing petal‐like rutile TiO2 wrapped by ultrathin graphene‐rich layers are proposed to fabricate superior anodes for sodium‐ion batteries, featuring high‐rate capabilities and ...long‐term cyclelife, benefiting from promoted electron transport and a shortened Na+ diffusion length. High capacities of 144.4 mA h g−1 (at 837.5 mA g−1) after 1100 cycles and 74.6 mA h g−1 (at 3350 mA g−1) after 4000 cycles are delivered outstandingly.
Interconnected carbon nanofibers networks (ICNNs) prepared through the carbonization of polypyrrole (PPy) precursor are utilized as conductive pathways and buffer to improve the Na storage ...performance of antimony (Sb) as anode for sodium-ion batteries (SIBs). The as-obtained Sb/ICNNs composite exhibits excellent cycle stability. The reversible capacity can remain 542.5 mAh g−1 with a high capacity retention of 96.7% after 100 cycles at a current density of 100 mA g−1. And the superior rate performance is also observed, the reversible capacity can still reach 325 mAh g−1 at a high current density of 3200 mA g−1. These great electrochemical performances observed above suggest that this type of composite can be a nice option for advanced SIBs anode materials and may be extended to other active materials/ICNNs composite electrode.
Interconnected carbon nanofibers networks (ICNNs) prepared through the carbonization of polypyrrole (PPy) precursor are employed to anchor Sb nanoparticles. The as-obtained Sb/ICNNs composite is applied as anode material for sodium-ion batteries (SIBs), delivering excellent cycle stability and rate performance. Display omitted
•Sb/interconnected carbon nanofibers networks composite is prepared.•The composite is firstly applied as anode material for sodium-ion battery.•The composite exhibits superior cycle stability and rate capacity.•This type of composite can be extended to other electrode materials.
The prevalence and outcomes of patients who had re-activation of coronavirus disease 2019 (COVID-19) after discharge remain poorly understood. We included 126 consecutively confirmed cases of ...COVID-19 with 2-month follow-up data after discharge in this retrospective study. The upper respiratory specimen using a reverse-transcription polymerase chain reaction test of three patients (71 years 60–76) were positive within 11–20 days after their discharge, with an event rate of 19.8 (95%CI 2.60–42.1) per 1,000,000 patient-days. Moreover, all re-positive patients were asymptomatic. Our findings suggest that few recovered patients may still be virus carriers even after reaching the discharge criteria.
•Phytic acid was used to modify hydrotalcite films by adsorption or ion exchange way.•The corrosion resistance of hydrotalcite films is improved by modification using phytic acid.•Phytic acid ...modification provides a self-healing effect to hydrotalcite film.
An environmentally friendly corrosion inhibitor phytic acid (PA) has been successfully added to modify the hydrotalcite (HT) film by adsorption and ion exchange approaches. In alkali PA solution, PO43- cannot substitute CO32- in the HT, but adsorb to the external surface; H2PO4-/HPO42- can insert into the HT after decarbonation under acidic condition. Partial decomposition occurs under both conditions. The PA/pH 11-HT film shows superior stability and lasting protective efficiency, and also can provide self-healing effect associated with the P adsorption in the filament. The worse resistance of the PA/pH 6.5-HT film may be related to the micro-cracks.
► It is the first time that a Mg–Al hydrotalcite film is prepared on the Mg alloys of low Al content. ► The environmentally friendly two-step in situ growth method can shorten the formation time to 2
...h. ► This film is very compact and uniform, which can provide effective protection to the AZ31 alloy. ► The film formation mechanism was also proposed based on the
OCP measurement and surface analysis.
In situ growth of Mg–Al hydrotalcite conversion film on AZ31 alloy has been developed by a two-step method. The characteristics of the films were investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electronic microscope (SEM) observation, electrochemical and immersion tests. The film formation process was proposed based on the open circuit potential (
OCP) measurements and surface analysis. A precursor film with network cracks is first formed and then this film is transformed into a compact and uniform hydrotalcite (Mg
6Al
2(OH)
16CO
3·4H
2O) film after the post treatment. This dense Mg–Al hydrotalcite film can provide effective protection to the AZ31 alloy.
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