The development of flexible and wearable devices is mainly required for tactile sensing;as such devices can adapt to complicated nonuniform surfaces,they can be applied to the human ***,it remains necessary to simulta...
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The development of flexible and wearable devices is mainly required for tactile sensing;as such devices can adapt to complicated nonuniform surfaces,they can be applied to the human ***,it remains necessary to simultaneously achieve small-scale,portable,and stable developments in such ***,this work aims at fabricating a novel,lightweight,ultra-flexible,and fiber-shaped coaxial structure with a diameter of 0.51 mm using polydimethylsiloxane/graphene/nylon material,based on piezoresistive and triboelectric *** piezoresistive-based robotic-hand-controlled sensor thus realized exhibits a response time of 120 ms and a fast recovery time of 55 ***,the piezoresistive-based sensors effectively feature whisker/joystick-guided behaviors and also sense the human finger *** to the triboelectric-based selfpowered nanogenerator behavior,the resulting sensor can convert mechanical motion into electrical energy,without adversely affecting human ***,this triboelectric-based human finger sensor can be operated under different bending modes at specific ***,this multifunctional sensor is cost-effective and suitable for various applications,including robotichand-controlled operations in medical surgery,whisker/joystick motions in lightweight drone technology,and navigation with highsensitivity components.
The critical challenges of the energy crisis and environmental degradation promote innovative approaches for energy ***-based photocatalytic technology,which transforms solar energy into chemical energy,emerges as a p...
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The critical challenges of the energy crisis and environmental degradation promote innovative approaches for energy ***-based photocatalytic technology,which transforms solar energy into chemical energy,emerges as a promising ***,the practical application of this technology faces several challenges,such as the rapid recombination of photogenerated electrons and holes,significantly limiting photocatalytic *** this review,we provide a detailed discussion,an insightful perspective,and a critical evaluation of recent advances,challenges,and opportunities in the field of photocatalysis using polar *** present a comprehensive examination of the photocatalytic mechanisms,activity,and diverse applications of photocatalysts based on polar *** also briefly discuss the engineering design of polar photocatalysis in experiments and its scalability in the *** review outlines future trends and potential breakthroughs in the photocatalytic field using polar materials,projecting their transformative impact on environmental chemistry and energy engineering.
Wire arc-directed energy deposition(WADED)has shown great advantages and potential in fabricating large-scale aluminum(Al)alloy ***,WADED Al alloys typically exhibit low strength and reliability due to pore defects an...
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Wire arc-directed energy deposition(WADED)has shown great advantages and potential in fabricating large-scale aluminum(Al)alloy ***,WADED Al alloys typically exhibit low strength and reliability due to pore defects and lack of work hardening or precipitation *** study utilized a combination of laser shock peening(LSP)and annealing to regulate the microstructure of WADED Al-Mg4.5Mn alloy and enhance mechanical *** effects of LSP and annealing on phase composition,pore distribution,and microstructures at multiple scales were systematically investigated to reveal the mechanical property improving *** results demonstrated that LSP-induced plastic deformation formed a defect-free zone by closing near-surface pore *** created the hardened layer with gradient mechanical properties by inducing gradient changes in grain size,the number of low-angle grain boundaries(LAGBs),and dislocation density along the depth *** annealing process promoted grain coarsening and reduced excessive dislocations and LAGBs,weakening the work harden-ing effect caused by ***,the high-density dislocations and high stored energy generated by LSP accelerated the recrystallization,facilitating growth of near-surface *** defect-free zone,dislocation strengthening,and LAGBs strengthening were responsible for the increase in strength,while the synergistic deformation between hardened layers and soft core facilitated maintaining excellent *** strength and elongation of WADED Al alloy can be synergistically improved by balancing the effects of LSP and heat treatment.
The ground state electron density—obtainable using Kohn-Sham Density Functional Theory(KSDFT)simulations—contains a wealth of material information,making its prediction via machine learning(ML)models ***,the computa...
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The ground state electron density—obtainable using Kohn-Sham Density Functional Theory(KSDFT)simulations—contains a wealth of material information,making its prediction via machine learning(ML)models ***,the computational expense of KS-DFT scales cubically with system size which tends to stymie training data generation,making it difficult to develop quantifiably accurate ML models that are applicable across many scales and system ***,we address this fundamental challenge by employing transfer learning to leverage the multi-scale nature of the training data,while comprehensively sampling systemconfigurations using *** ML models are less reliant on heuristics,and being based on Bayesian neural networks,enable uncertainty *** show that our models incur significantly lower data generation costs while allowing confident—and when verifiable,accurate—predictions for a wide variety of bulk systems well beyond training,including systems with defects,different alloy compositions,and at multi-million-atom ***,such predictions can be carried out using only modest computational resources.
Green hydrogen production is crucial for a sustainable future,but current catalysts for the oxygen evolution reaction(OER)suffer from slow kinetics,despite many efforts to produce optimal designs,particularly through ...
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Green hydrogen production is crucial for a sustainable future,but current catalysts for the oxygen evolution reaction(OER)suffer from slow kinetics,despite many efforts to produce optimal designs,particularly through the calculation of descriptors for *** this study,we develop a dataset of density functional theory calculations of bulk and surface perovskite oxides,and adsorption energies of OER intermediates,which includes compositions up to quaternary and facets up to(555).We demonstrate that per-site properties of perovskite oxides such as Bader charge or band center can be tuned through element substitution and faceting,and develop a machine learning model that accurately predicts these properties directly from the local chemical *** leverage these per-site properties to identify promising perovskites with high theoretical OER *** identified design principles and promising materials provide a roadmap for closing the gap between current artificial catalysts and biological enzymes such as photosystem II.
The electron microscope provides numerous insights into physics, from demonstrations of fundamental quantummechanical principles to the physics of imaging and materials. It reveals the atomic and electronic structure ...
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The electron microscope provides numerous insights into physics, from demonstrations of fundamental quantummechanical principles to the physics of imaging and materials. It reveals the atomic and electronic structure of key regionssuch as defects and interfaces. We can learn the underlying physics governing properties, and gain insight into how tosynthesize new materials with improved properties. Some recent advances and possible future directions are discussed.
The switching characteristics of ferroelectrics and multiferroics are influenced by the interaction of topological defects with domain *** report on the pinning of polarization due to antiphase boundaries in thin film...
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The switching characteristics of ferroelectrics and multiferroics are influenced by the interaction of topological defects with domain *** report on the pinning of polarization due to antiphase boundaries in thin films of the multiferroic hexagonal YbFeO_(3).We have directly resolved the atomic structure of a sharp antiphase boundary(APB)in YbFeO_(3) thin films using a combination of aberration-corrected scanning transmission electron microscopy(STEM)and total energy calculations based on density-functional theory(DFT).We find the presence of a layer of FeO_(6) octahedra at the APB that bridges the adjacent *** imaging shows a reversal in the direction of polarization on moving across the APB,which DFT calculations confirm is structural in nature as the polarization reversal reduces the distortion of the FeO_(6) octahedral layer at the *** APBs in hexagonal perovskites are expected to serve as domain-wall pinning sites and hinder ferroelectric switching of the domains.
Niobium(Nb)is sensitive to even minute quantities of silicon(Si)solutes,which are known to induce pronounced ***,the underlying mechanism for hardening remains elusive since the ef-fect of Si solutes on dislocation be...
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Niobium(Nb)is sensitive to even minute quantities of silicon(Si)solutes,which are known to induce pronounced ***,the underlying mechanism for hardening remains elusive since the ef-fect of Si solutes on dislocation behavior is ***,using tensile testing,in-situ microscopy and nanomechanical testing,the behavior of dislocations in dilute Nb-Si alloys,containing from 0 at.%to 0.8 at.%Si,is *** show that the hardness,strength and strain hardening rate increase from two to four times,while the uniform elongation in tension only reduces 50%as the Si content *** evolve from complex entangled patterns in Nb to parallel long-straight screw dislocation-dominated structures in Nb-Si ***-situ indentation reveals that the origins of the marked harden-ing in Nb-Si alloy are the reduction of dislocation mobility and cross-slip *** densities of dislocation debris-superjogs and loops introduced throughout the sample during warm rolling and an-nealing are found to provide active internal dislocation sources,which explain the minimal ductility loss seen in these Nb-Si *** findings can help guide the alloy design of high-performance refractory materials for extreme temperature applications.
In perovskite EuTiO_(3),the magnetic characteristics and magnetocaloric effect(MCE) can be flexibly regulated by converting the magnetism from antiferromagnetic to *** the present work,a series of Eu(Ti,Nb,Mn)O_(3) co...
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In perovskite EuTiO_(3),the magnetic characteristics and magnetocaloric effect(MCE) can be flexibly regulated by converting the magnetism from antiferromagnetic to *** the present work,a series of Eu(Ti,Nb,Mn)O_(3) compounds,abbreviated as ETNMO for convenience of description,was fabricated and their crystallography,magnetism together with cryogenic magnetocaloric effects were systematically *** crystallographic results demonstrate the cubic perovskite structure for all the compounds,with the space group of *** magnetic phase transitions are observed in these second-order phase transition(SOPT) *** joint substitution of elements Mn and Nb can considerably manipulate the magnetic phase transition process and magnetocaloric performance of the ETNMO *** the Mn content increases,gradually widened-ΔS_(M)-T curves are obtained,and two peaks with a broad shoulder are observed in the-ΔS_(M)-T curves for Δμ_(0)H≤0-1 *** a field change of 0-5 T,the values of maximum magnetic entropy change(-ΔS_(M)^(max)) and refrigeration capacity(RC) are evaluated to be 34.7 J/(kg·K) and 364.9 J/kg for EuTi_(0.8625)Nb_(0.0625)Mn_(0.075)O_(3), 27.8 J/(kg·K) and367.6 J/kg for EuTi_(0.8375)Nb_(0.0625)Mn_(0.1)O_(3),23.2 J/(kg·K) and 369.2 J/kg for EuTi_(0.8125)Nb_(0.0625)Mn_(0.125)O_(3),17.1 J/(kg·K) and 357.6 J/kg for EuTi_(0.7875)Nb_(0.0625)Mn_(0.15)O_(3),*** co nsiderable MCE parameters make the ETNMO compounds potential candidates for cryogenic magnetic refrigeration.
Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected...
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Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.
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