Silicon monoxide(SiOx) has garnered considerable attention as an anode material owing to its high ***, its commercial viability is hampered by the low conductivity and inadequate cycling stability. In this study, a ...
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Silicon monoxide(SiOx) has garnered considerable attention as an anode material owing to its high ***, its commercial viability is hampered by the low conductivity and inadequate cycling stability. In this study, a micrometer-scale silicon oxide/carbon composite(1000-SiOx/NC) was developed based on the porous and high electrical conductivity of pyrolyzed polydopamine(PDA) and the high-temperature disproportionation of SiOx. Electrochemical impedance spectroscopy(EIS) and X-ray photoelectron spectroscopy(XPS)analyses confirmed that the pyrolysis of polydopamine(PDA) not only improves electrode conductivity but also contributes to the formation of a stable solid electrolyte interface(SEI). Additionally, SiOxundergoes disproportionation reactions during the pyrolysis of PDA, further the improves the cyclic stability of the ***, the 1000-SiOx/NC composite electrode exhibited an impressive specific capacity of 783.4 mAh·g-1after 500 cycles at 1 A g-1, maintaining 80.1 % of its initial capacity. Additionally, at a high rate of 3 C, its capacity reached 607.3 mAh·g-1The synthesis approach is both straightforward and economical, offering a fresh avenue for the widespread commercial deployment of SiOx.
Selective oxidation of propane to acetone(AC)with H_(2) and O_(2) provides a direct route to convert low-cost propane into valueadded ***,the catalytic activity of conventional Au/Ti-based catalysts is constrained by ...
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Selective oxidation of propane to acetone(AC)with H_(2) and O_(2) provides a direct route to convert low-cost propane into valueadded ***,the catalytic activity of conventional Au/Ti-based catalysts is constrained by the high energy barrier for H_(2) ***,uncalcined TS-1 supported Au-Pd bimetallic catalysts were prepared,and the relationship between the active-site structure and corresponding performance in the selective oxidation of propane with H_(2) and O_(2) in the gas phase was systematically *** contrast to the liquid-phase reaction,trace Pd alloyed with Au triggered an increase in both catalytic activity and selectivity,in which Au_(20)-Pd_(1)/TS-1-B catalyst exhibited excellent activity(170 gAC·h^(−1)·kgcat^(−1))and AC selectivity(90.6%),much higher than those of the Au/TS-1-B catalyst(AC formation rate of 100 gAC·h^(−1)·kgcat^(−1)and AC selectivity of 86.3%).It was found that Pd was gradually isolated into monomers with the increase of Au/Pd molar ratio,and the synergy between Pd single atoms and Au improved the catalytic performance via enhancing hydrogen dissociation and modulating the electronic structure of ***,the reaction conditions were optimized based on the kinetics studies and the Au_(20)-Pd_(1)/TS-1-B catalyst exhibited enhanced H_(2) selectivity(45%)and long-term stability(over 130 h).The insights gained here can offer valuable guidance for the design of Au-Pd catalysts applicable to other gas-phase oxidation reactions.
Compared to 2D imaging data,the 4D light field(LF)data retains richer scene’s structure information,which can significantly improve the computer’s perception capability,including depth estimation,semantic segmentati...
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Compared to 2D imaging data,the 4D light field(LF)data retains richer scene’s structure information,which can significantly improve the computer’s perception capability,including depth estimation,semantic segmentation,and LF ***,there is a contradiction between spatial and angular resolution during the LF image acquisition *** overcome the above problem,researchers have gradually focused on the light field super-resolution(LFSR).In the traditional solutions,researchers achieved the LFSR based on various optimization frameworks,such as Bayesian and Gaussian *** learning-based methods are more popular than conventional methods because they have better performance and more robust generalization *** this paper,the present approach can mainly divided into conventional methods and deep learning-based *** discuss these two branches in light field spatial super-resolution(LFSSR),light field angular super-resolution(LFASR),and light field spatial and angular super-resolution(LFSASR),***,this paper also introduces the primary public datasets and analyzes the performance of the prevalent approaches on these ***,we discuss the potential innovations of the LFSR to propose the progress of our research field.
Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chain...
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Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains. In this work, crosslinked polyimide fibers(CPI fibers) were produced by intrinsic carboxyl decarboxylation for the first time. The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers) was studied, and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃. The PIC fibers were hotdrawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature. The CPI fibers had high tensile strengths(0.72-1.46 GPa) and compressive strengths(401-604 MPa). The oriented macromolecules and chemically crosslinked structure improved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance. The CPI-50 fiber did not dissolve in a 0.5 wt% NaOH solution during heating at 90 ℃ for 10 h, and the tensile strength retention reached 87% when treated in 0.5 wt% NaOH solutions at 90 ℃ for 1 h, providing a guarantee for its application in alkaline corrosive environments.
The concentric internally heat-integrated distillation column(HIDi C) has advantages of low energy consumption and high thermodynamic efficiency. However, its drawbacks of limited heat transfer area,complex internal s...
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The concentric internally heat-integrated distillation column(HIDi C) has advantages of low energy consumption and high thermodynamic efficiency. However, its drawbacks of limited heat transfer area,complex internal structure, and large number of control parameters hinder its widespread industrial applications. To solve these challenges, in this work a novel sleeve-like concentric heat-integrated separation column, namely temperature-controlled phase change column(TCPC), was developed to separate liquid mixtures in a more effective and energy-saving way with reflux section being moved and trays being replaced with spiral corrugation blades. The comprehensive performances of TCPC in ethanol-water system was firstly evaluated by experiments. The results showed that TCPC performs well in ethanol-water separation due to the internal spiral corrugation significantly reducing the vapor-liquid contact in separation section. Meanwhile, compared to the concentric HIDi C, TCPC has a higher total heat transfer coefficient due to the larger heat transfer area. Computational fluid dynamics simulation reveals the internal design of TCPC inducing secondary vortices of the vapor, enhancing condensation heat transfer and separation efficiency. Further, increasing the mass flow rate within a certain range would enhance the comprehensive performance factor and lead to more effective separation.
The development of a durable metallic coating on diverse substrates is both intriguing and challenging,particularly in the research of metal-conductive materials for applications such as batteries,soft electronics,and...
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The development of a durable metallic coating on diverse substrates is both intriguing and challenging,particularly in the research of metal-conductive materials for applications such as batteries,soft electronics,and ***,by learning from the pencil-writing process,a facile solid-ink rubbing technology(SIR-tech)is invented to address the above *** solid-ink is exampled by rational combination of liquid metal and graphite *** harnessing the synergistic effects between rubbing and adhesion,controllable metallic skin is successfully formed onto metals,woods,ceramics,and plastics without limitation in size and ***,outperforming pure liquid-metal coating,the composite metallic skin by SIR-tech is very robust due to the self-lamination of graphite nanoplate exfoliated by liquid-metal *** critical factors controlling the structures-properties of the composite metallic skin have been systematically investigated as *** applications,the SIR-tech is demonstrated to fabricate high-performance composite current collectors for next-generation batteries without traditional metal ***,advanced skin-electrodes are further demonstrated for stable triboelectricity generation even under temperature fluctuation from-196 to 120℃.This facile and highly-flexible SIR-tech may work as a powerful platform for the studies on functional coatings by liquid metals and beyond.
The quest for scalable integration of monolayer graphene into functional composites confronts the bottleneck of high-fidelity transfer onto substrates,crucial for unlocking graphene’s full potential in advanced *** t...
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The quest for scalable integration of monolayer graphene into functional composites confronts the bottleneck of high-fidelity transfer onto substrates,crucial for unlocking graphene’s full potential in advanced *** this,our research introduces the camphor-assisted transfer(CAT)method,a novel approach that surmounts common issues of residue and structural deformation endemic to existing *** in the sublimation dynamics of camphor,the CAT method achieves a clean,contiguous transfer of centimeter-scale monolayer graphene onto an array of polymer films,including ultra-thin polyethylene *** resultant ultrathin graphene-polyethylene(gPE)films,characterized by their exceptional transparency and conductivity,reveal the CAT method’s unique ability to preserve the pristine quality of graphene,underscoring its practicality for preparing flexible transparent electrodes by monolayer ***-depth mechanism investigation into the camphor sublimation during CAT has led to a pivotal realization:the porosity of the target polymer substrate is a determinant in achieving high-quality graphene *** that camphor sublimates initially from the polymer side is crucial to prevent the formation of wrinkles or delamination of *** extensive examination of CAT on a spectrum of commonly used polymer films,including PE,PP,PTFE,PI and PET,we have confirmed this important *** discovery offers crucial guidance for fabricating monolayer graphene-polymer composite films using methods akin to CAT,underscoring the significance of substrate selection in the transfer process.
Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research *** dielectric permittivity of the grafted surface is typically significantly different from that of solution,which r...
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Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research *** dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric *** is thus important to study how SP alters the PEB’s structure and *** this work,the SP effects on PEB structure was studied using a statistical thermodynamic *** free energy functional to describe SP effect was constructed by using the image-charge ***,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into *** the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent *** the presence of SP,the collapse became a jump-like *** energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of *** theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.
Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. Th...
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Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. This structural feature causes chain slippage in PP under stress,significantly constraining its service lifetime. In this study, thermally reduced graphene oxide(TrGO) nanosheets were incorporated into the PP matrix, yielding a nanocomposite with exceptional creep resistance performance. Results demonstrated that at a stress of 25 MPa, a 2.0 wt% TrGO content could enhance the creep failure lifetime of PP by 21.5 times compared to neat PP. Rheology, transmission electron microscopy(TEM),and scanning electron microscopy(SEM) characterization techniques were employed to analyze the mechanism of TrGO's influence on PP's creep behavior. It was observed that when TrGO content exceeded 1.0 wt%, an effective particle network structure formed within the PP matrix. This homogeneously dispersed TrGO-formed particle network structure restricted the migration and rearrangement of PP molecular chains, enabling prolonged stress resistance without structural failure. By combining the time-strain superposition method with the critical failure strain as a criterion, generalized creep compliance curves for PP and its composites were established, facilitating the prediction of material creep failure lifetimes, with a strong agreement between experimental and predicted lifetime values. This research proposes a novel strategy aimed at developing polypropylene materials and products with enhanced long-term stability and durability, thus extending service life, reducing failure risk, and broadening their potential across various application domains.
The primary dendrite spacing(PDS) and segregation of directionally solidified single crystal(SC) superalloy under the longitudinal magnetic field(LMF) were investigated based on the analysis of the whole cross-section...
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The primary dendrite spacing(PDS) and segregation of directionally solidified single crystal(SC) superalloy under the longitudinal magnetic field(LMF) were investigated based on the analysis of the whole cross-sectional microstructure at different solidification distances. The results show that the PDS under the LMF remains basically unchanged at different solidification distances, and it is greater than that under no LMF. With the increase of magnetic field intensity, the PDS increases and the macrosegregation decreases. The increasing PDS and reducing segregation under the LMF can be attributed to the increase of solute boundary layer, which expands the non-equilibrium freezing temperature range and brings the effective partition coefficient closer to 1. The increase of the solute enrichment layer thickness could be caused by the downward secondary circulation generated by the thermoelectric magnetic convection(TEMC) near the interface, which drives the migration of solutes towards the interdendritic region. This work not only clarifies the mechanism of LMF controlling PDS and reducing segregation by TEMC, but also provides theoretical guidance for producing high-quality SC superalloys using magnetic fields.
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