Bilayer MoS2 is a promising channel candidate for extending Moore’s law,owing to its optimal channel thickness and improved suppression of extrinsic scattering compared to monolayers.However,its intrinsic phonon-limi...Bilayer MoS2 is a promising channel candidate for extending Moore’s law,owing to its optimal channel thickness and improved suppression of extrinsic scattering compared to monolayers.However,its intrinsic phonon-limited electron mobility is severely limited by enhanced K–Q intervalley scattering arising from the multivalley conduction band feature inherent to the bilayer structure.To overcome this bottleneck,we propose a“valley separation engineering”strategy that combines a twist angle near 30°with applied stress.Our first-principles calculations demonstrate that although valley separation can be continuously increased using this strategy,the electron mobility saturates at∼200 cm^(2)⋅V^(−1)⋅s^(−1).The saturation is attributed to the competition between the reduced effective mass and enhanced intravalley scattering induced by phonon softening once the detrimental intervalley scattering is effectively suppressed by sufficient valley separation.This study establishes a theoretical upper limit for the intrinsic electron transport of bilayer MoS2 masked by severe intervalley scattering.展开更多
Metal-organic frameworks(MOFs)have been widely applied in the field of electromagnetic wave absorption(EMWA)on account of unique morphology,simple fabrication,and ultra-high porosity.Nevertheless,the facile method of ...Metal-organic frameworks(MOFs)have been widely applied in the field of electromagnetic wave absorption(EMWA)on account of unique morphology,simple fabrication,and ultra-high porosity.Nevertheless,the facile method of protecting its structure from being destroyed remains challenging.Herein,we proposed a hydrothermal method combined with a carbonization strategy to construct the 0D/1D/2D Fe_(3)C@NC@Mo_(2)C/Fe_(3)C composites.Owing to the incorporation of polydopamine(PDA),the carbon shell formed during high-temperature carbonization effectively protected the original MIL-88A rod-like structure,and the 2D Mo_(2)C nano-sheets and 1D Fe_(3)C nanoparticles were coated on the surface of 1D Fe_(3)C nanorods.With the increase in carbonization temperature,the EMWA properties of the composites presented a trend of first increasing and then decreasing.Impressively,the composites(at 750℃)exhibited praiseworthy EMWA performances with a minimum reflection loss value of−43.70 dB at 8.00 GHz,alongside a maximum effective absorption bandwidth of 6.08 GHz(11.20-17.28 GHz).Density functional theory calculations confirmed the distinctive charge distribution resulting from the heterointerface,which is beneficial to the polarization loss and conductive loss.As a result,the outstanding EMWA performance was credited to the distinctive hierarchical structure,appropriate impedance matching,numerous heterogeneous interfaces,and magnetic loss.Moreover,Radar cross-section calculations indicated that the composites have tremendous potential for practical application.Thus,this work may pave new avenues for designing high-performance and structure-controllable absorbing materials.展开更多
This research conducted a systematic study on the processes of migration of energy-related pollutants caused by nanoparticles in marine sediments,as well as their impacts on the durability of offshore infrastructure.W...This research conducted a systematic study on the processes of migration of energy-related pollutants caused by nanoparticles in marine sediments,as well as their impacts on the durability of offshore infrastructure.While focused on representative nanoparticles(nano-TiO_(2),nano-Fe_(3)O_(4),and carbon nanotubes)and select energy pollutants,experimental data showed these materials greatly enhanced the movement of pollutants,increasing migration distances from 1.6 to 2.9 times.The carbon nanotubes possessed the greatest carrying effect,increasing the phenanthrene migration distance by 286 percent.The study determined surface properties of nanoparticles,pH of the liquid environment,ionic concentration,and organic matter level as major elements impacting pollutant mobility.Laboratory simulations,while controlled and reproducible,necessarily simplified the complex dynamics of real marine environments.Nanoparticle-sorbate systems were found to be effective in enhancing the deterioration rate of materials used in offshore constructions,with CNTPAHs composites causing carbon steel to corrode by 183% more than if PAHs were used without the composites.This change in corrosion behaviour was shown in other tests to be caused by a change in dynamics of the corrosion products'structural constituents and the various electrochemical properties present on the surface of the material.Samples of concrete showed a spend of 90 days in the composite system resulted in a 26.8% decrease in compressive strength compared to control conditions which had only a 15.3%.Therefore,taking into account the results,strategies were formulated to ensure durability for offshore infrastructure including surface modified anticorrosion coatings,surveillance and alert systems,and integrated protective systems.Future field validation studies are needed to verify these laboratory findings under actual marine conditions.This study helps to comprehend the behaviour of nanoparticles in intricate marine ecosystems,providing support for the sustainable advancement of offshore infrastructure and the protection of the marine environment.展开更多
Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study eva...Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study evaluates polyvinyl acetate(PVAc),a thermoplastic polymer,as a selective flocculant to enhance reverse flot ation separation of chalcopyrite from ultrafine talc.Flotation tests showed that at a PVAc dosage of 40 mg/L,talc can be effectively and selectively removed,enabling efficient separation.Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation,while chalcopyrite lacks suitable binding sites.PVAc adsorption also enhances talc hydrophobicity.Furthermore,particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles,shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment.This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective,while expanding the potential of ester-based polymers for ultrafine mineral recovery.展开更多
Currently,carbon materials derived from biomass are widely sought after as electromagnetic absorbing(EMWA)materials owing to the unique structure,as well as the wide range of natural acquisition pathways,economic viab...Currently,carbon materials derived from biomass are widely sought after as electromagnetic absorbing(EMWA)materials owing to the unique structure,as well as the wide range of natural acquisition pathways,economic viability,and simple processing.However,due to the high dielectric properties,mismatched impedance and single attenuation mechanism,they cannot achieve efficient EMWA performance.Herein,the biomass carbon/Co/porous carbon magnetic composites with a layered gradient structure were fabricated by in-situ deposition of ZIF-67 on the lotus leaf base and then pyrolysis at high temperature.By adjusting the pyrolysis temperature,the sample obtained at 650℃ achieved a minimum reflection value(RLmin)of-34.2dB at a matching thickness of 2.6mm,and a maximum effective absorption bandwidth(EAB)of 7.12GHz.The results indicate that this magnetic composite with a multi-sized layered gradient porous structure has a good electron transport network,a large number of heterogeneous interfaces,and dipole polarization centers,which are conducive to multiple reflection and scattering of microwaves,conduction loss,interface loss,magnetic loss,and impedance matching of materials.Therefore,this work provided a reference for optimizing the EMWA performance of carbon materials and designing a layered gradient porous magnetic composite with multi-sized structure.展开更多
Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-...Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-relevant systems.In this study,we present a model system to study two-dimensional(2D)water layers under ambient conditions by using self-assembled monolayers(SAMs)supporting the physisorp-tion of the Cytochrome C(Cyt C)protein layer.We observed that the 2D island-like water layers were uniformly distributed on the SAMs as characterized by atomic force microscopy,and their composition was confirmed by nano-atomic force microscopy-infrared spectroscopy and Raman spectroscopy.In addition,these 2D flakes could grow under high-humidity conditions or melt upon the introduction of a heat source.The formation of these flakes is attributed to the activation energy for water desorption from the Cyt C being nearly twofold high than that from the SAMs.Our results provide a new and effective method for further understanding the water–protein interactions.展开更多
High-mobility semiconductor nanotubes have demonstrated great potential for applications in high-speed transistors,single-charge detection,and memory devices.Here we systematically investigated the electronic properti...High-mobility semiconductor nanotubes have demonstrated great potential for applications in high-speed transistors,single-charge detection,and memory devices.Here we systematically investigated the electronic properties of single-walled boron antimonide(BSb)nanotubes using first-principles calculations.We observed that rolling the hexagonal boron antimonide monolayer into armchair(ANT)and zigzag(ZNT)nanotubes induces compression and wrinkling effects,significantly modifying the band structures and carrier mobilities through band folding andπ^(*)-σ^(*)hybridization.As the chiral index increases,the band gap and carrier mobility of ANTs decrease monotonically,where electron mobility consistently exceeds hole mobility.In contrast,ZNTs exhibit a more complex trend:the band gap first increases and then decreases,and the carrier mobility displays oscillatory behavior.In particular,both ANTs and ZNTs could exhibit significantly higher carrier mobilities compared to hexagonal monolayer and zinc-blende BSb,reaching 10^(-3)-10^(-7) cm^(-2)·V^(-1)·s^(-1).Our findings highlight strong curvature-induced modifications in the electronic properties of single-walled BSb nanotubes,demonstrating the latter as a promising candidate for high-performance electronic devices.展开更多
Flexible electronic skin(E-skin)sensors offer innovative solutions for detecting human body signals,enabling human-machine interactions and advancing the development of intelligent robotics.Electrospun nanofibers are ...Flexible electronic skin(E-skin)sensors offer innovative solutions for detecting human body signals,enabling human-machine interactions and advancing the development of intelligent robotics.Electrospun nanofibers are particularly wellsuited for E-skin applications due to their exceptional mechanical properties,tunable breathability,and lightweight nature.Nanofiber-based composite materials consist of three-dimensional structures that integrate one-dimensional polymer nanofibers with other functional materials,enabling efficient signal conversion and positioning them as an ideal platform for next-generation intelligent electronics.Here,this review begins with an overview of electrospinning technology,including far-field electrospinning,near-field electrospinning,and melt electrospinning.It also discusses the diverse morphologies of electrospun nanofibers,such as core-shell,porous,hollow,bead,Janus,and ribbon structure,as well as strategies for incorporating functional materials to enhance nanofiber performance.Following this,the article provides a detailed introduction to electrospun nanofiber-based composite materials(i.e.,nanofiber/hydrogel,nanofiber/aerogel,nanofiber/metal),emphasizing their recent advancements in monitoring physical,physiological,body fluid,and multi-signal in human signal detection.Meanwhile,the review explores the development of multimodal sensors capable of responding to diverse stimuli,focusing on innovative strategies for decoupling multiple signals and their state-of-the-art advancements.Finally,current challenges are analyzed,while future prospects for electrospun nanofiber-based composite sensors are outlined.This review aims to advance the design and application of next-generation flexible electronics,fostering breakthroughs in multifunctional sensing and health monitoring technologies.展开更多
The task of detecting fraud in credit card transactions is crucial to ensure the security and stability of a financial system,as well as to enforce customer confidence in digital payment systems.Historically,credit ca...The task of detecting fraud in credit card transactions is crucial to ensure the security and stability of a financial system,as well as to enforce customer confidence in digital payment systems.Historically,credit card companies have used rulebased approaches to detect fraudulent transactions,but these have proven inadequate due to the complexity of fraud strategies and have been replaced by much more powerful solutions based on machine learning or deep learning algorithms.Despite significant progress,the current approaches to fraud detection suffer from a number of limitations:for example,it is unclear whether some transaction features are more effective than others in discriminating fraudulent transactions,and they often neglect possible correlations among transactions,even though they could reveal illicit behaviour.In this paper,we propose a novel credit card fraud detection(CCFD)method based on a transaction behaviour-based hierarchical gated network.First,we introduce a feature-oriented extraction module capable of identifying key features from original transactions,and such analysis is effective in revealing the behavioural characteristics of fraudsters.Second,we design a transaction-oriented extraction module capable of capturing the correlation between users’historical and current transactional behaviour.Such information is crucial for revealing users’sequential behaviour patterns.Our approach,called transactional-behaviour-based hierarchical gated network model(TbHGN),extracts two types of new transactional features,which are then combined in a feature interaction module to learn the final transactional representations used for CCFD.We have conducted extensive experiments on a real-world credit card transaction dataset with an increase in average F1 between 1.42%and 6.53%and an improvement in average AUC between 0.63%and 2.78%over the state of the art.展开更多
NiMn-MOF was prepared via one-step hydrothermal method,and then Ni/MnO/C composites were synthesized by high-temperature pyrolysis.The findings indicate that the sample acquired at the pyrolysis temperature of 700℃ d...NiMn-MOF was prepared via one-step hydrothermal method,and then Ni/MnO/C composites were synthesized by high-temperature pyrolysis.The findings indicate that the sample acquired at the pyrolysis temperature of 700℃ demonstrate superior microwave absorption capabilities.The minimum reflection value achieves-19.2 dB at a thickness of 1.4mm,and the effective absorption bandwidth extends to 5.04 GHz at a mere 1.6mm.The exceptional microwave absorption proficiency can be ascribed to the multiple reflections and scattering generated by the material’s unique porous spherical structure,optimized impedance matching,suitable conduction loss,rich interfacial and dipole polarization,and magnetic loss.This study presents a straightforward procedural technique for the fabrication of effective composite absorbers.展开更多
The asymmetric molecular design strategy,with advantages in modulating the molecular dipole moment and intermolecular interactions and achieving more favorable molecular packing and orientation,has been an effective a...The asymmetric molecular design strategy,with advantages in modulating the molecular dipole moment and intermolecular interactions and achieving more favorable molecular packing and orientation,has been an effective approach for designing high-performance nonfullerene acceptors(NFAs).Herein,two asymmetric NFAs,Y-CN-2F and Y-CN-2Cl,were designed and synthesized by introducing a linear alkyl chain terminated with the 4-cyanobiphenyl group,a well-known mesogenic unit,at one of the inner pyrrole positions instead of the normal 2-butyloctyl branched alkyl chain.The difference between Y-CN-2F and Y-CN-2Cl is the terminated IC-groups,which was modified with F and Cl halogens,respectively.Both NFAs displayed strong absorption in the near-infrared to visible-light range,which is complementary to that of typical medium-bandgap donor polymers.After optimization with D18 donor in organic solar cells(OSCs),Y-CN-2F and Y-CN-2Cl provided comparable power conversion efficiencies(PCEs)of 15.33%and 15.88%.While the D18:Y-CN-2F based devices displayed higher fill factors(FFs),those based on D18:Y-CN-2Cl exhibited higher current densities and open-circuit voltages.The Y-CN-2Cl film showed longer light absorption than YCN-2F,which is beneficial for more light harvesting.Moreover,D18:Y-CN-2Cl displayed a lower fluorescence lifetime and faster carrier transfer processes,which could be attributed to its higher mobility.For the D18:Y-CN-2F blended film,a more pronounced fiber network structure and balanced carrier mobility were observed,which contributed to the higher FFs values.This work presents new efforts to develop more asymmetric NFAs with specific functional segments for efficient organic electronics.展开更多
The prediction of new fluorooxoborates as ultraviolet(UV)/deep ultraviolet(DUV)opto-electronic functional materials from a largely unexplored chemical space is a challenging task.It has been suggested that the anionic...The prediction of new fluorooxoborates as ultraviolet(UV)/deep ultraviolet(DUV)opto-electronic functional materials from a largely unexplored chemical space is a challenging task.It has been suggested that the anionic frameworks formed by B–O and B–O–F units significantly determine the physical properties of fluorooxoborates.Therefore,the rational design of anionic frameworks could facilitate the materials discovery process.Herein,we propose that a candidate anionic framework can be efficiently derived from an existing one by slightly altering its oxygen content.Following this idea,we hypothesized the existence of a 1D[B_(3)O_(5)F]_(∞)chain from the wellknown 2D[B_(6)O_(9)F_(2_)]_(∞)layer.Accordingly,seven CaB_(3)O_(5)F structures with the expected anionic framework were successfully predicted.First-principles calculations show that all these structures have potential in the UV/DUV birefringent or nonlinear optical(NLO)material field,indicating that the 1D[B_(3)O_(5)F]_(∞)chain is indeed a promising anionic framework for achieving UV/DUV birefringent and NLO performance.展开更多
Glass is the precious material evidence of the trade of the early Silk Road. The ancient glass was easily affected by the environmental impact and weathering, and the change of composition ratios affected the correct ...Glass is the precious material evidence of the trade of the early Silk Road. The ancient glass was easily affected by the environmental impact and weathering, and the change of composition ratios affected the correct judgment of its category. In this paper, mathematical models and methods such as Chi-square test, weighted average method, principal component analysis, cluster analysis, binary classification model and grey correlation analysis were used comprehensively to analyze the data of sample glass products combined with their categories. The results showed that the weathered high-potassium glass could be divided into 12, 9, 10 and 27, 7, 22 and so on.展开更多
基金supported by the National Key R&D Program of China (Grant No.2022YFA1402503)the High Performance Computing Center of Jilin University,China。
文摘Bilayer MoS2 is a promising channel candidate for extending Moore’s law,owing to its optimal channel thickness and improved suppression of extrinsic scattering compared to monolayers.However,its intrinsic phonon-limited electron mobility is severely limited by enhanced K–Q intervalley scattering arising from the multivalley conduction band feature inherent to the bilayer structure.To overcome this bottleneck,we propose a“valley separation engineering”strategy that combines a twist angle near 30°with applied stress.Our first-principles calculations demonstrate that although valley separation can be continuously increased using this strategy,the electron mobility saturates at∼200 cm^(2)⋅V^(−1)⋅s^(−1).The saturation is attributed to the competition between the reduced effective mass and enhanced intravalley scattering induced by phonon softening once the detrimental intervalley scattering is effectively suppressed by sufficient valley separation.This study establishes a theoretical upper limit for the intrinsic electron transport of bilayer MoS2 masked by severe intervalley scattering.
基金financially supported by the National Natu-ral Science Foundation of China(Nos.52173267,21667019,and 22066017)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.22KJB430043).
文摘Metal-organic frameworks(MOFs)have been widely applied in the field of electromagnetic wave absorption(EMWA)on account of unique morphology,simple fabrication,and ultra-high porosity.Nevertheless,the facile method of protecting its structure from being destroyed remains challenging.Herein,we proposed a hydrothermal method combined with a carbonization strategy to construct the 0D/1D/2D Fe_(3)C@NC@Mo_(2)C/Fe_(3)C composites.Owing to the incorporation of polydopamine(PDA),the carbon shell formed during high-temperature carbonization effectively protected the original MIL-88A rod-like structure,and the 2D Mo_(2)C nano-sheets and 1D Fe_(3)C nanoparticles were coated on the surface of 1D Fe_(3)C nanorods.With the increase in carbonization temperature,the EMWA properties of the composites presented a trend of first increasing and then decreasing.Impressively,the composites(at 750℃)exhibited praiseworthy EMWA performances with a minimum reflection loss value of−43.70 dB at 8.00 GHz,alongside a maximum effective absorption bandwidth of 6.08 GHz(11.20-17.28 GHz).Density functional theory calculations confirmed the distinctive charge distribution resulting from the heterointerface,which is beneficial to the polarization loss and conductive loss.As a result,the outstanding EMWA performance was credited to the distinctive hierarchical structure,appropriate impedance matching,numerous heterogeneous interfaces,and magnetic loss.Moreover,Radar cross-section calculations indicated that the composites have tremendous potential for practical application.Thus,this work may pave new avenues for designing high-performance and structure-controllable absorbing materials.
文摘This research conducted a systematic study on the processes of migration of energy-related pollutants caused by nanoparticles in marine sediments,as well as their impacts on the durability of offshore infrastructure.While focused on representative nanoparticles(nano-TiO_(2),nano-Fe_(3)O_(4),and carbon nanotubes)and select energy pollutants,experimental data showed these materials greatly enhanced the movement of pollutants,increasing migration distances from 1.6 to 2.9 times.The carbon nanotubes possessed the greatest carrying effect,increasing the phenanthrene migration distance by 286 percent.The study determined surface properties of nanoparticles,pH of the liquid environment,ionic concentration,and organic matter level as major elements impacting pollutant mobility.Laboratory simulations,while controlled and reproducible,necessarily simplified the complex dynamics of real marine environments.Nanoparticle-sorbate systems were found to be effective in enhancing the deterioration rate of materials used in offshore constructions,with CNTPAHs composites causing carbon steel to corrode by 183% more than if PAHs were used without the composites.This change in corrosion behaviour was shown in other tests to be caused by a change in dynamics of the corrosion products'structural constituents and the various electrochemical properties present on the surface of the material.Samples of concrete showed a spend of 90 days in the composite system resulted in a 26.8% decrease in compressive strength compared to control conditions which had only a 15.3%.Therefore,taking into account the results,strategies were formulated to ensure durability for offshore infrastructure including surface modified anticorrosion coatings,surveillance and alert systems,and integrated protective systems.Future field validation studies are needed to verify these laboratory findings under actual marine conditions.This study helps to comprehend the behaviour of nanoparticles in intricate marine ecosystems,providing support for the sustainable advancement of offshore infrastructure and the protection of the marine environment.
基金supported by the National Natural Science Foundation of China(Nos.52174239 and 52374259)the Program of China Scholarship Council(No.202406080114)Natural Sciences and Engineering Research Council of Canada(No.NSERC RGPIN 2024-04570).
文摘Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study evaluates polyvinyl acetate(PVAc),a thermoplastic polymer,as a selective flocculant to enhance reverse flot ation separation of chalcopyrite from ultrafine talc.Flotation tests showed that at a PVAc dosage of 40 mg/L,talc can be effectively and selectively removed,enabling efficient separation.Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation,while chalcopyrite lacks suitable binding sites.PVAc adsorption also enhances talc hydrophobicity.Furthermore,particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles,shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment.This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective,while expanding the potential of ester-based polymers for ultrafine mineral recovery.
基金supported by the National Natural Science Foundation of China(Nos.21667019,22066017,and 52173267)the Aviation Science Foundation of China(No.2017ZF56020).
文摘Currently,carbon materials derived from biomass are widely sought after as electromagnetic absorbing(EMWA)materials owing to the unique structure,as well as the wide range of natural acquisition pathways,economic viability,and simple processing.However,due to the high dielectric properties,mismatched impedance and single attenuation mechanism,they cannot achieve efficient EMWA performance.Herein,the biomass carbon/Co/porous carbon magnetic composites with a layered gradient structure were fabricated by in-situ deposition of ZIF-67 on the lotus leaf base and then pyrolysis at high temperature.By adjusting the pyrolysis temperature,the sample obtained at 650℃ achieved a minimum reflection value(RLmin)of-34.2dB at a matching thickness of 2.6mm,and a maximum effective absorption bandwidth(EAB)of 7.12GHz.The results indicate that this magnetic composite with a multi-sized layered gradient porous structure has a good electron transport network,a large number of heterogeneous interfaces,and dipole polarization centers,which are conducive to multiple reflection and scattering of microwaves,conduction loss,interface loss,magnetic loss,and impedance matching of materials.Therefore,this work provided a reference for optimizing the EMWA performance of carbon materials and designing a layered gradient porous magnetic composite with multi-sized structure.
基金supported by the National Natural Science Foundation of China(22273045,52488101 and 22472043)Ningbo Youth Science and Technology Innovation Leading Talent(2023QL041)Tsinghua University Independent Scientific Research Plan for Young Investigator,Tsinghua University Dushi Program,and Initiative Scientific Research Program。
文摘Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-relevant systems.In this study,we present a model system to study two-dimensional(2D)water layers under ambient conditions by using self-assembled monolayers(SAMs)supporting the physisorp-tion of the Cytochrome C(Cyt C)protein layer.We observed that the 2D island-like water layers were uniformly distributed on the SAMs as characterized by atomic force microscopy,and their composition was confirmed by nano-atomic force microscopy-infrared spectroscopy and Raman spectroscopy.In addition,these 2D flakes could grow under high-humidity conditions or melt upon the introduction of a heat source.The formation of these flakes is attributed to the activation energy for water desorption from the Cyt C being nearly twofold high than that from the SAMs.Our results provide a new and effective method for further understanding the water–protein interactions.
基金Project supported by the National Key R&D Program of China(Grant Nos.2022YFA1402503,2023YFA1406200,2023YFB3003001)the National Natural Science Foundation of China(Grant Nos.12074138 and 12047530)+2 种基金the Interdisciplinary Integration and Innovation Project of JLUFundamental Research Funds for the Central Universitiesthe Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)。
文摘High-mobility semiconductor nanotubes have demonstrated great potential for applications in high-speed transistors,single-charge detection,and memory devices.Here we systematically investigated the electronic properties of single-walled boron antimonide(BSb)nanotubes using first-principles calculations.We observed that rolling the hexagonal boron antimonide monolayer into armchair(ANT)and zigzag(ZNT)nanotubes induces compression and wrinkling effects,significantly modifying the band structures and carrier mobilities through band folding andπ^(*)-σ^(*)hybridization.As the chiral index increases,the band gap and carrier mobility of ANTs decrease monotonically,where electron mobility consistently exceeds hole mobility.In contrast,ZNTs exhibit a more complex trend:the band gap first increases and then decreases,and the carrier mobility displays oscillatory behavior.In particular,both ANTs and ZNTs could exhibit significantly higher carrier mobilities compared to hexagonal monolayer and zinc-blende BSb,reaching 10^(-3)-10^(-7) cm^(-2)·V^(-1)·s^(-1).Our findings highlight strong curvature-induced modifications in the electronic properties of single-walled BSb nanotubes,demonstrating the latter as a promising candidate for high-performance electronic devices.
基金supported by the National Natural Science Foundation of China(22302110,22375047,22378068)National Key Research and Development Program of China(2022YFB3804905)+1 种基金the Open Project Foundation of Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University(No.KJS2210)High-level Talent Initiative Project at Anhui Agricultural University(rc362401)。
文摘Flexible electronic skin(E-skin)sensors offer innovative solutions for detecting human body signals,enabling human-machine interactions and advancing the development of intelligent robotics.Electrospun nanofibers are particularly wellsuited for E-skin applications due to their exceptional mechanical properties,tunable breathability,and lightweight nature.Nanofiber-based composite materials consist of three-dimensional structures that integrate one-dimensional polymer nanofibers with other functional materials,enabling efficient signal conversion and positioning them as an ideal platform for next-generation intelligent electronics.Here,this review begins with an overview of electrospinning technology,including far-field electrospinning,near-field electrospinning,and melt electrospinning.It also discusses the diverse morphologies of electrospun nanofibers,such as core-shell,porous,hollow,bead,Janus,and ribbon structure,as well as strategies for incorporating functional materials to enhance nanofiber performance.Following this,the article provides a detailed introduction to electrospun nanofiber-based composite materials(i.e.,nanofiber/hydrogel,nanofiber/aerogel,nanofiber/metal),emphasizing their recent advancements in monitoring physical,physiological,body fluid,and multi-signal in human signal detection.Meanwhile,the review explores the development of multimodal sensors capable of responding to diverse stimuli,focusing on innovative strategies for decoupling multiple signals and their state-of-the-art advancements.Finally,current challenges are analyzed,while future prospects for electrospun nanofiber-based composite sensors are outlined.This review aims to advance the design and application of next-generation flexible electronics,fostering breakthroughs in multifunctional sensing and health monitoring technologies.
基金supported in part by the National Natural Science Foundation of China(61972241)the Natural Science Foundation of Shanghai(24ZR1427500,22ZR1427100)+1 种基金the Key Projects of Natural Science Research in Anhui Higher Education Institutions(2022AH051909)Bengbu University 2021 High-Level Scientific Research and Cultivation Project(2021pyxm04).
文摘The task of detecting fraud in credit card transactions is crucial to ensure the security and stability of a financial system,as well as to enforce customer confidence in digital payment systems.Historically,credit card companies have used rulebased approaches to detect fraudulent transactions,but these have proven inadequate due to the complexity of fraud strategies and have been replaced by much more powerful solutions based on machine learning or deep learning algorithms.Despite significant progress,the current approaches to fraud detection suffer from a number of limitations:for example,it is unclear whether some transaction features are more effective than others in discriminating fraudulent transactions,and they often neglect possible correlations among transactions,even though they could reveal illicit behaviour.In this paper,we propose a novel credit card fraud detection(CCFD)method based on a transaction behaviour-based hierarchical gated network.First,we introduce a feature-oriented extraction module capable of identifying key features from original transactions,and such analysis is effective in revealing the behavioural characteristics of fraudsters.Second,we design a transaction-oriented extraction module capable of capturing the correlation between users’historical and current transactional behaviour.Such information is crucial for revealing users’sequential behaviour patterns.Our approach,called transactional-behaviour-based hierarchical gated network model(TbHGN),extracts two types of new transactional features,which are then combined in a feature interaction module to learn the final transactional representations used for CCFD.We have conducted extensive experiments on a real-world credit card transaction dataset with an increase in average F1 between 1.42%and 6.53%and an improvement in average AUC between 0.63%and 2.78%over the state of the art.
基金financially supported by the National Natural Science Foundation of China(Nos.20904019,51273089,52173267)the Aviation Science Foundation of China(No.2017ZF56020)the First Training-class High-end Talents Projects of Science and Technology Innovation in Jiangxi Province(No.CK202002473).
文摘NiMn-MOF was prepared via one-step hydrothermal method,and then Ni/MnO/C composites were synthesized by high-temperature pyrolysis.The findings indicate that the sample acquired at the pyrolysis temperature of 700℃ demonstrate superior microwave absorption capabilities.The minimum reflection value achieves-19.2 dB at a thickness of 1.4mm,and the effective absorption bandwidth extends to 5.04 GHz at a mere 1.6mm.The exceptional microwave absorption proficiency can be ascribed to the multiple reflections and scattering generated by the material’s unique porous spherical structure,optimized impedance matching,suitable conduction loss,rich interfacial and dipole polarization,and magnetic loss.This study presents a straightforward procedural technique for the fabrication of effective composite absorbers.
基金financially supported by the National Natural Science Foundation of China(Nos.22465018,52163018 and 22405107)of ChinaJiangxi Provincial Department of Science and Technology(Nos.20232BBE50026,jxsq2023102153,20232BAB21302 and 2024SSY05132)Jiangxi Academy of Sciences(Nos.2023YYB07,2022YSBG22031,2022YJC2019,2022YJC2017,2023YSBG21017,2022YYB10,2022YRCS002,2023YJC1001,and 2023YSBG22025)。
文摘The asymmetric molecular design strategy,with advantages in modulating the molecular dipole moment and intermolecular interactions and achieving more favorable molecular packing and orientation,has been an effective approach for designing high-performance nonfullerene acceptors(NFAs).Herein,two asymmetric NFAs,Y-CN-2F and Y-CN-2Cl,were designed and synthesized by introducing a linear alkyl chain terminated with the 4-cyanobiphenyl group,a well-known mesogenic unit,at one of the inner pyrrole positions instead of the normal 2-butyloctyl branched alkyl chain.The difference between Y-CN-2F and Y-CN-2Cl is the terminated IC-groups,which was modified with F and Cl halogens,respectively.Both NFAs displayed strong absorption in the near-infrared to visible-light range,which is complementary to that of typical medium-bandgap donor polymers.After optimization with D18 donor in organic solar cells(OSCs),Y-CN-2F and Y-CN-2Cl provided comparable power conversion efficiencies(PCEs)of 15.33%and 15.88%.While the D18:Y-CN-2F based devices displayed higher fill factors(FFs),those based on D18:Y-CN-2Cl exhibited higher current densities and open-circuit voltages.The Y-CN-2Cl film showed longer light absorption than YCN-2F,which is beneficial for more light harvesting.Moreover,D18:Y-CN-2Cl displayed a lower fluorescence lifetime and faster carrier transfer processes,which could be attributed to its higher mobility.For the D18:Y-CN-2F blended film,a more pronounced fiber network structure and balanced carrier mobility were observed,which contributed to the higher FFs values.This work presents new efforts to develop more asymmetric NFAs with specific functional segments for efficient organic electronics.
基金supported by the National Natural Science Foundation of China(Grant No.52403305)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0880000)+1 种基金Tianchi Talent Program of Xinjiang Uygur Autonomous Region(Grant No.2024000068)Postdoctoral Fellow-ship Program(Grade C)(Grant No.GZC20232959)。
文摘The prediction of new fluorooxoborates as ultraviolet(UV)/deep ultraviolet(DUV)opto-electronic functional materials from a largely unexplored chemical space is a challenging task.It has been suggested that the anionic frameworks formed by B–O and B–O–F units significantly determine the physical properties of fluorooxoborates.Therefore,the rational design of anionic frameworks could facilitate the materials discovery process.Herein,we propose that a candidate anionic framework can be efficiently derived from an existing one by slightly altering its oxygen content.Following this idea,we hypothesized the existence of a 1D[B_(3)O_(5)F]_(∞)chain from the wellknown 2D[B_(6)O_(9)F_(2_)]_(∞)layer.Accordingly,seven CaB_(3)O_(5)F structures with the expected anionic framework were successfully predicted.First-principles calculations show that all these structures have potential in the UV/DUV birefringent or nonlinear optical(NLO)material field,indicating that the 1D[B_(3)O_(5)F]_(∞)chain is indeed a promising anionic framework for achieving UV/DUV birefringent and NLO performance.
文摘Glass is the precious material evidence of the trade of the early Silk Road. The ancient glass was easily affected by the environmental impact and weathering, and the change of composition ratios affected the correct judgment of its category. In this paper, mathematical models and methods such as Chi-square test, weighted average method, principal component analysis, cluster analysis, binary classification model and grey correlation analysis were used comprehensively to analyze the data of sample glass products combined with their categories. The results showed that the weathered high-potassium glass could be divided into 12, 9, 10 and 27, 7, 22 and so on.
