The heat input during laser welding process has significant influence on microstructure and properties of the joints, whereas there is currently limited research concerning the influence of heat ...input during laser welding process of β titanium alloys. The microstructure and tensile properties of laser welded Ti–3Al–6Mo–2Fe–2Zr (wt.%) joints under different heat inputs were investigated in this paper. Numerical simulation process was used to explain the microstructure evolution in HAZ and fusion zone. The microstructure of HAZ is divided into three different regions from fusion line to base metal. In near-HAZ, mid-HAZ, and far-HAZ, the microstructures are composed of single β phase, β + αp, and β + αp + retained αs, respectively. In fusion zone, the microstructure consists of single β phase because of the fast cooling rate and high content of β stabilizing elements. The ultimate tensile strength (UTS) of laser welded specimens is lower than that of base metal due to the lack of strengthening phase and the coarsening of β grains. Higher heat input further exacerbates the coarsening of β grains in the fusion zone and HAZ, which consequently results in the decrement of UTS of the joints.
Programming 2D sheets to form 3D shapes is significant for flexible electronics, soft robots, and biomedical devices. Stress regulation is one of the most used methods, during which external force is ...usually needed to keep the stress, leading to complex processing setups. Here, by introducing dynamic diselenide bonds into shape‐memory materials, unconstrained shape programming with light is achieved. The material could hold and release internal stress by themselves through the shape‐memory effect, simplifying programming setups. The fixed stress could be relaxed by light to form stress gradients, leading to out‐of‐plane deformations through asymmetric contractions. Benefiting from the variability of light irradiation, complex 3D configurations can be obtained conveniently from 2D polymer sheets. Besides, remotely controlled “4D assembly” and actuation, including object transportation and self‐lifting, can be achieved by sequential deformation. Taking advantage of the high spatial resolution of light, this material can also produce 3D microscopic patterns. The light‐induced stress gradients significantly simplify 3D shape programming procedures with improved resolution and complexity and have great potential in soft robots, smart actuators, and anti‐counterfeiting techniques.
Through introducing light‐responsive diselenide bonds into polymer films, homogeneous stress fixed by shape‐memory effect can be relaxed to form a stress gradient. Once the stress gradient is activated, various deformations, including bending, folding, twisting, and helix, can be realized through the asymmetric contraction, which can be further combined for 3D shape programming, sequential deformation, and microscopic optical patterning.
Degradable polymers offer a promising solution to mitigate global plastic pollution, but the degraded products often suffer from diminished value. Upcycling is a more sustainable approach to upgrade ...polymer waste into value‐added products. Herein, we report a β‐selenocarbonyl‐containing polyurethane (SePU), which can be directly degraded under mild conditions into valuable selenium fertilizers for selenium‐rich vegetable cultivation globally, enabling both plastic degradation and waste upcycling. Under oxidation condition, this polymer can be easily and selectively degraded via selenoxide elimination reaction from mixed plastic waste. The degraded product can serve as effective selenium fertilizers to increase selenium content in radish and pak choi. The SePU exhibits excellent mechanical properties. Additionally, we observed the formation of spherulites‐like selenium particles within the materials during degradation for the first time. Our research offers a successful application of selenoxide elimination reaction in the field of plastic degradation for the first time, endowing plastics with both degradability and high reusable value. This strategy provides a promising solution to reduce pollution and improve economy and sustainability of plastics.
The selenium‐containing polyurethane materials are degraded into selenium fertilizers for selenium‐rich plant cultivation and further improvement of selenium‐deficiency within humans via selenoxide elimination reaction, achieving both the degradation and upcycling of plastic waste, offering a more sustainable plastic economy.
Significant progresses have been made in tellurium-containing polymers over the past decades. Just like other heteroatom-containing polymers, tellurium-containing polymers exhibit several unique ...properties and promising applications. However, unlike elements such as boron, silicon, sulfur and so on, tellurium in polymers remains a fresh perspective for many researchers. In this review, we shall illustrate the diversification of tellurium-containing polymers and their respective synthetic methods. Besides, the properties of tellurium-containing polymers including redox-responsiveness, coordination properties, optoelectronic properties and so on will be discussed in detail. Furthermore, the performances of tellurium-containing polymers in biomedicine, optoelectronic materials and some recent advanced fields will be demonstrated. Overall, by reviewing the recent developments and trends of tellurium-containing polymers, we wish to popularize the concepts and it is anticipated that this review could function as an easy-to-read and comprehensive handbook to provide some inspirations and possible scientific supports for researchers in the field of chemistry and materials.
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Two-dimensional (2D) ferroelectric materials, which possess electrically switchable spontaneous polarization and can be easily integrated with semiconductor technologies, is of utmost importance in ...the advancement of high-integration low-power nanoelectronics. Despite the experimental discovery of certain 2D ferroelectric materials such as CuInP
2
S
6
and In
2
Se
3
, achieving stable ferroelectricity at room temperature in these materials continues to present a significant challenge. Herein, stable ferroelectric order at room temperature in the 2D limit is demonstrated in van der Waals SnP
2
S
6
atom layers, which can be fabricated via mechanical exfoliation of bulk SnP
2
S
6
crystals. Switchable polarization is observed in thin SnP
2
S
6
of ∼7 nm. Importantly, a van der Waals ferroelectric field-effect transistor (Fe-FET) with ferroelectric SnP
2
S
6
as top-gate insulator and p-type WTe
0.6
Se
1.4
as the channel was designed and fabricated successfully, which exhibits a clear clockwise hysteresis loop in transfer characteristics, demonstrating ferroelectric properties of SnP
2
S
6
atomic layers. In addition, a multilayer graphene/SnP
2
S
6
/multilayer graphene van der Waals vertical heterostructure phototransistor was also fabricated successfully, exhibiting improved optoelectronic performances with a responsivity (
R
) of 2.9 A/W and a detectivity (
D
) of 1.4 × 10
12
Jones. Our results show that SnP
2
S
6
is a promising 2D ferroelectric material for ferroelectric-integrated low-power 2D devices.
In hierarchical cognitive radio networks, edge or cloud servers utilize the data collected by edge devices for modulation classification, which, however, is faced with problems of the computation ...load, transmission overhead, and data privacy. In this article, an edge learning (EL) based framework jointly mobilizing the edge device and the edge server for intelligent co-inference is proposed to realize the collaborative automatic modulation classification (C-AMC) between them. A spectrum semantic compression neural network is designed for the edge device to compress the collected raw data into a compact semantic embedding that is then sent to the edge server via the wireless channel. On the edge server side, a modulation classification neural network combining the bidirectional long-short term memory and attention structures is elaborated to determine the modulation type from the noisy semantic embedding. The C-AMC framework decently balances the computation resources of both sides while avoiding the high transmission overhead and data privacy leakage. Both the offline and online training procedures of the C-AMC framework are elaborated. The compression strategy of the C-AMC framework is also developed to further facilitate the deployment, especially for the resource-constrained edge device. Simulation results show the superiority of the EL-based C-AMC framework in terms of the classification accuracy, computational complexity, and the data compression rate as well as reveal useful insights paving the practical implementation.
Modern Olympics have increasingly benefited from the advancement of materials science. From February 4 to March 13, 2022, the whole world has witnessed spectacular Olympic Winter Games and Winter ...Paralympic Games held in Beijing, during which nanotechnologies are extensively applied and play indispensable roles in many aspects. Although these nanotechnologies appear in a very small length scale, they have provided tremendous support to all athletes with the pursuit of “faster, higher, stronger”. In this Article, we highlight several representative nanotechnologies applied in the Olympic and Paralympic Winter Games including nanoscience in ice skating, wearable monitoring devices, skiing sports equipment, winter protection, and Olympic printing and discuss their physicochemical principles, unique significance for athletes and sports.
Zn metal has been extensively utilized as an anode in aqueous zinc-ion batteries attributed to its affordable cost and superior theoretical capacity. Nevertheless, the presence of dendrites and ...undesirable side reactions poses challenges to its widespread commercialization. To address these issues, herein, a surface coating composed of hydroxyapatite (HAP) was developed on the Zn anode to create an artificial solid electrolyte interphase. After the application of a hydroxyapatite layer, dendrites and corrosion of the Zn anode are sufficiently inhibited. Furthermore, the hydroxyapatite interphase with a low ionic diffusion barrier enables fast anodic redox kinetics. Consequently, the Zn@HAP symmetric cell possesses a durable lifespan over 2000 h at 1 mA cm–2, while maintaining minimal polarization. Moreover, the practical feasibilities of the Zn@HAP anode are also manifested in full batteries combined with MnO2 cathodes, exhibiting exceptional cycling performance up to 500 cycles at 1 A g–1 and excellent rate capability with a retention of 109 mAh g–1 at 5 A g–1.
Rampant dendrites and parasitic reactions have been seriously hampering the application of Zn metal anode. The construction of artificial interface layer is considered to be an effective strategy to ...solve these problems. Herein, we designed an organic-inorganic hybrid interface coating to regulate zinc deposition behavior. The chitin-rich outer layer with abundant polar groups exhibits good zincophilicity, as well as the good trapping ability to SO42- and H2O molecule, thereby promoting the rapid desolvation of Zn2+ and inhibiting the parasitic reactions. The vermiculite-rich inner layer promotes the multi-site nucleation and leads to the uniform deposition of Zn2+, which also works as a tough physical parclose to inhibit dendrite growth. Moreover, according to the experimental results and theoretical calculation, the chitin-vermiculite interface supplies a fast diffusion path with low energy barriers, enabling fast zinc deposition kinetics. As a result, the hybrid coating protected Zn anode (denoted as Zn@VMCT) exhibits high electrochemical reversibility of average CE up to 99.6% in Zn||Cu battery, long plating/stripping lifespan of 2800 h under 1 mA cm−2/1 mAh cm−2 and exceeding 400 h under 10 mA cm−2/10 mAh cm−2 in symmetrical battery. Impressively, when paired with MnO2 cathode, the Zn@VMCT||MnO2 full battery delivers 201.0 mAh g−1 at 1 A g−1 and maintains 92.9% after 800 cycles.
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•An organic-inorganic hybrid interface coating was constructed on Zn anode.•The hybrid coating shows good electrolyte sieve ability and dendrite resistance.•The hybrid coating shows a low diffusion battier for Zn2+ ions.•The hybrid coating enables the long-term and high-capacity Zn deposition.
The non-uniformity and transient nature of laser-produced plasma are critical factors that affect the analysis of the extreme ultraviolet spectra of highly charged ions and the diagnosis of plasma ...states. This paper systematically investigates the characteristics of extreme ultraviolet radiation and the hydrodynamic evolution of laser-produced nickel plasmas from two perspectives: high-spatio-temporal-resolution extreme-ultraviolet spectroscopic measurement and radiation hydrodynamics simulation. The consistency between the four-band experimental spectra and their theoretically simulated spectra confirms the accuracy of the atomic structure parameters and plasma state parameters. We also analyze the significant contribution of the 3 d -4 f double-excited state radiation to the spectral profile and discuss the influence of the self-absorption caused by plasma opacity on the characteristics of extreme ultraviolet radiation. The findings are crucial for accurately understanding the characteristics of extreme ultraviolet radiation, the hydrodynamic evolution, and the application of medium- and high-Z laser-produced plasma as a pulsed short-wavelength light source.
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