Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of a...Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.展开更多
As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and el...As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.展开更多
A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface...A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property.展开更多
This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This m...This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem.展开更多
Owing to their rolling friction,two-dimensional piston pumps are highly suitable as power components for electro-hydrostatic actuators(EHAs).These pumps are particularly advantageous for applications requiring high ef...Owing to their rolling friction,two-dimensional piston pumps are highly suitable as power components for electro-hydrostatic actuators(EHAs).These pumps are particularly advantageous for applications requiring high efficiency and reliability.However,the ambiguity surrounding the output flow characteristics of individual two-dimensional pumps poses a significant challenge in achieving precise closed-loop control of the EHA positions.To address this issue,this study established a comprehensive numerical model that included gap leakage to analyze the impact of leakage on the output flow characteristics of a two-dimensional piston pump.The validity of the numerical analysis was indirectly confirmed through meticulous measurements of the leakage and volumetric efficiency,ensuring robust results.The research findings indicated that,at lower pump speeds,leakage significantly affected the output flow rate,leading to potential inefficiencies in the system.Conversely,at higher rotational speeds,the impact of leakage was less pronounced,implying that the influence of leakage on the pump outlet flow must be carefully considered and managed for EHAs to perform position servo control.Additionally,the research demonstrates that two-dimensional motion does not have a unique or additional effect on pump leakage,thus simplifying the design considerations.Finally,the study concluded that maintaining an oil-filled leakage environment is beneficial because it helps reduce the impact of leakage and enhances the overall volumetric efficiency of the pump system.展开更多
The pursuit of sustainable hydrogen production has positioned water electrolysis as a cornerstone technology for global carbon neutrality.However,sluggish kinetics,catalyst scarcity,and system integration challenges h...The pursuit of sustainable hydrogen production has positioned water electrolysis as a cornerstone technology for global carbon neutrality.However,sluggish kinetics,catalyst scarcity,and system integration challenges hinder its widespread deployment.Ultrathin two-dimensional(2D)materials,with their atomically exposed surfaces,tunable electronic structures,and defect-engineering capabilities,present unique opportunities for next-generation electrocatalysts.This review provides an integrated overview of ultrathin 2D electrocatalysts,discussing their structural diversity,synthetic routes,structure-activity relationships,and mechanistic understanding in water electrolysis processes.Special focus is placed on the translation of 2D materials from laboratory research to practical device implementation,emphasizing challenges such as scalable fabrication,interfacial engineering,and operational durability in realistic electrolyzer environments.The role of advanced characterization techniques in capturing dynamic structural changes and active site evolution is discussed.Finally,we outline future research directions,emphasizing the synergy of machine learning-driven materials discovery,advanced operando characterization,and scalable system integration to accelerate the industrial translation of 2D electrocatalysts for green hydrogen production.展开更多
Vehicle electrification,an important method for reducing carbon emissions from road transport,has been promoted globally.In this study,we analyze how individuals adapt to this transition in transportation and its subs...Vehicle electrification,an important method for reducing carbon emissions from road transport,has been promoted globally.In this study,we analyze how individuals adapt to this transition in transportation and its subsequent impact on urban structure.Considering the varying travel costs associated with electric and fuel vehicles,we analyze the dynamic choices of households concerning house locations and vehicle types in a two-dimensional monocentric city.A spatial equilibrium is developed to model the interactions between urban density,vehicle age and vehicle type.An agent-based microeconomic residential choice model dynamically coupled with a house rent market is developed to analyze household choices of home locations and vehicle energy types,considering vehicle ages and competition for public charging piles.Key findings from our proposed models show that the proportion of electric vehicles(EVs)peaks at over 50%by the end of the first scrappage period,accompanied by more than a 40%increase in commuting distance and time compared to the scenario with only fuel vehicles.Simulation experiments on a theoretical grid indicate that heterogeneity-induced residential segregation can lead to urban sprawl and congestion.Furthermore,households with EVs tend to be located farther from the city center,and an increase in EV ownership contributes to urban expansion.Our study provides insights into how individuals adapt to EV transitions and the resulting impacts on home locations and land use changes.It offers a novel perspective on the dynamic interactions between EV adoption and urban development.展开更多
The diffusion trajectory of a Brownian particle passing over the saddle point of a two-dimensional quadratic potential energy surface is tracked in detail according to the deep learning strategies.Generative adversari...The diffusion trajectory of a Brownian particle passing over the saddle point of a two-dimensional quadratic potential energy surface is tracked in detail according to the deep learning strategies.Generative adversarial networks(GANs)emanating in the category of machine learning(ML)frameworks are used to generate and assess the rationality of the data.While their optimization is based on the long short-term memory(LSTM)strategies.In addition to drawing a heat map,the optimal path of two-dimensional(2D)diffusion is simultaneously demonstrated in a stereoscopic space.The results of our simulation are completely consistent with the previous theoretical predictions.展开更多
Two-dimensional(2D)semiconductors have emerged as an ideal platform for fundamental research and a promising candidate beyond silicon materials in future transistors due to their ultrathin thickness and excellent elec...Two-dimensional(2D)semiconductors have emerged as an ideal platform for fundamental research and a promising candidate beyond silicon materials in future transistors due to their ultrathin thickness and excellent electrical properties.However,the practical application of 2D semiconductors still faces significant challenges.The excellent interface quality of traditional silicon-based semiconductor devices is crucial for their outstanding performance,whereas the interface issues in 2D semiconductor/dielectric systems remain unresolved,resulting in device performance far below expectations.Therefore,further study of the interface in 2D semiconductor/dielectric systems and finding appropriate methods to quantify interface quality,as well as interface optimization strategies,are critical for driving the practical application of 2D semiconductors.In this review,we discuss the issues existing at the 2D semiconductor/dielectric interface,quantitative characterization methods and optimization strategies for interface quality.This includes comparing the advantages and disadvantages of traditional characterization methods for silicon-based semiconductors when applied to 2D semiconductors,as well as the development of strategies to improve interface quality and enhance the performance of 2D devices.Finally,in the outlook,we outline the development directions for improving the interface quality of 2D semiconductor/dielectric systems.展开更多
Moiré superlattices have revolutionized the study of two-dimensional materials, enabling unprecedented control over their electronic, magnetic, optical, and mechanical properties. This review provides a comprehen...Moiré superlattices have revolutionized the study of two-dimensional materials, enabling unprecedented control over their electronic, magnetic, optical, and mechanical properties. This review provides a comprehensive analysis of the latest advancements in moiré physics, focusing on the formation of moiré superlattices due to rotational misalignment or lattice mismatch in two-dimensional materials. These superlattices induce flat band structures and strong correlation effects,leading to the emergence of exotic quantum phases, such as unconventional superconductivity, correlated insulating states,and fractional quantum anomalous Hall effects. The review also explores the underlying mechanisms of these phenomena and discusses the potential technological applications of moiré physics, offering insights into future research directions in this rapidly evolving field.展开更多
Hydrogen evolution reaction(HER)plays a crucial role in developing clean and renewable hydrogen energy technologies.However,conventional HER catalysts rely on expensive and scarce noble metals,which is a significant c...Hydrogen evolution reaction(HER)plays a crucial role in developing clean and renewable hydrogen energy technologies.However,conventional HER catalysts rely on expensive and scarce noble metals,which is a significant challenge for practical application.Recently,twodimensional transition metal dichalcogenides(2D-TMDs)have emerged as attractive and cost-effective alternatives for efficient electrocatalysis in the HER.Substantial efforts have been dedicated to advancing the synthesis and application of 2D-TMDs.This review highlights the design and synthesis of high-performance 2D-TMDs-based HER electrocatalysts by combining theoretical calculations with experimental methods.Subsequently,recent advances in synthesizing different types of 2D TMDs with enhanced HER activity are summarized.Finally,the conclusion and perspectives of the 2D TMDs-based HER electrocatalysts are discussed.We expect that this review will provide new insights into the design and development of highly efficient 2D TMDs-based HER electrocatalysts for industrial applications.展开更多
Organic magnetic semiconductors have aroused much attention for spintronic applications. However, it remains challenging to achieve organic semiconductors with strong room-temperature ferromagnetism. Here, we report a...Organic magnetic semiconductors have aroused much attention for spintronic applications. However, it remains challenging to achieve organic semiconductors with strong room-temperature ferromagnetism. Here, we report a two-dimensional (2D) tetragonal organic-inorganic ferrimagnetic (FIM) semiconductor of Fe_(14)Se_(16)(peha)_(0.7) (peha = pentaethylenehexamine) with excellent thermal stability and a Curie temperature (T_(C)) higher than 519 K. Magnetic and Mössbauer measurements reveal a long-range magnetic ordering in single crystalline Fe_(14)Se_(16)(peha)0.7 nanosheets. The saturation magnetization and coercivity are 5.9 emu g^(−1) and 0.42 kOe at 5 K, which slightly reduces to 4.6 emu g^(−1) and ∼0 Oe at 300 K. A direct optical bandgap of 2.22 eV is obtained by tuning electronic structure of β-Fe3Se4 host layers through spacer layers consisting of Fe^(3+) and peha. Electrical and Seebeck coefficient data indicate that the n-type semiconductor follows the thermally-activated conduction mechanism (lnρ ∝ T^(−1)) in a range of 130–300 K with an activation energy (Ea) of 62.69 meV. Thermal conductivity is 2.5 W m^(−1) K^(−1) at 300 K, while the Wiedemann–Franz law is strongly violated according to electrical-thermal transport data due to weak incorporation of organic spacer layers and host layers. This study sets the stage for exploiting new room-temperature organic magnetic semiconductor systems for spintronic materials.展开更多
Excessive nitrogen emission caused by human activities has significantly disrupted the global nitrogen cycle,adversely affecting ecosystems and human health.Electrocatalytic nitrate reduction to valuable ammonia(eNRA)...Excessive nitrogen emission caused by human activities has significantly disrupted the global nitrogen cycle,adversely affecting ecosystems and human health.Electrocatalytic nitrate reduction to valuable ammonia(eNRA)presents an encouraging alternative marked by mild reaction conditions,rapid reaction rates,and minimal byproduct pollution,successfully overcoming the challenges of the energy-intensive Haber-Bosch process.Recent innovations in two-dimensional(2D)electrocatalysts have emerged as a promising approach to enhance the efficiency and selectivity of this transformation.This review systematically examines the latest advancements in2D materials,including metals,metal compounds,nonmetallic elements,and organic frameworks,highlighting their unique electronic properties and high surface area that facilitate the electrocatalytic reactions.We explore strategies to optimize these catalysts,such as doping,heterostructure,and surface functionalization,which have shown significant improvements in catalytic performance.Furthermore,the role of in situ/operando characterization techniques in understanding the reaction mechanisms is highlighted,aiming to provide both theoretical and practical insights for the research and development of 2D nanoelectrocatalysts during eNRA.Additionally,future perspectives and ongoing challenges are discussed to offer insights for transitioning from experimental investigations to real-world applications.展开更多
Polarization-induced two-dimensional hole gases(2DHG)in GaN/AlGaN/GaN heterostructures offer a promising pathway for advancing p-channel transistors.This work investigates the impact of p-GaN thickness on hole distrib...Polarization-induced two-dimensional hole gases(2DHG)in GaN/AlGaN/GaN heterostructures offer a promising pathway for advancing p-channel transistors.This work investigates the impact of p-GaN thickness on hole distribution and transport through temperature-dependent Hall measurements and TCAD simulations.It is demonstrated that the p-channel is composed of holes both in the p-GaN layer and in the 2DHG at the GaN/AlGaN heterointerface at 300 K,whereas at 77 K,the p-channel conduction is dominated solely by the 2DHG at the GaN/AlGaN heterointerface.The results also reveal the formation of a polarization-induced 2DHG at the GaN/AlGaN interface,exhibiting a high sheet density of 2.2×10^(13)cm^(-2)and a mobility of 16.2 cm^(2)·V^(-1)·s^(-1)at 300 K.The 2DHG sheet density remains nearly independent of p-GaN thickness when the p-GaN layer exceeds 30 nm.However,for p-GaN layers thinner than 30 nm,the 2DHG sheet density strongly depends on the p-GaN thickness,which is attributed to the gradual extension of the depletion region toward the GaN/AlGaN interface under the influence of surface trap states.展开更多
This study explores the significance of using two-dimensional shear wave elastography(2D-SWE)to assess liver stiffness(LS)and spleen area(SPA)for predicting post-hepatectomy liver failure(PHLF).By providing a non-inva...This study explores the significance of using two-dimensional shear wave elastography(2D-SWE)to assess liver stiffness(LS)and spleen area(SPA)for predicting post-hepatectomy liver failure(PHLF).By providing a non-invasive method to measure LS,which correlates with the degree of liver fibrosis,and SPA,an indicator of portal hypertension,2D-SWE offers a comprehensive evaluation of a patient’s hepatic status.These advancements are particularly crucial in hepatic surgery,where accurate preoperative assessments are essential for optimizing surgical outcomes and minimizing complications.This letter highlights the prac-tical implications of integrating 2D-SWE into clinical practice,emphasizing its potential to improve patient safety and surgical precision by enhancing the ability to predict PHLF and tailor surgical approaches accordingly.展开更多
A recombinant inbred population (RI) was constructed from a cross between B5, an introgression. line from the wild rice Oryza officinalis Wall. ex Watt, and susceptible cultivar Minghui 63 ( O. sativa L.). The brown p...A recombinant inbred population (RI) was constructed from a cross between B5, an introgression. line from the wild rice Oryza officinalis Wall. ex Watt, and susceptible cultivar Minghui 63 ( O. sativa L.). The brown planthopper ( BPH) resistances of RI lines were evaluated. Based on bulked segregant analysis (BSA), two protein bulks were made by extracting proteins from equally mixed seedlings of extremely resistant and susceptible plants selected from the RI population, respectively. Two-dimensional electrophoresis was used to detect the changes of polypeptide pattern. Results showed that a protein P40 ( pI 6.3, Mw 40 kD) was significantly reduced or vanished after BPH infestation for 48 h in the susceptible bulk, while it remained uninfluenced in the resistant bulk. In connection with the physiological changes of the resistant and susceptible lines subjected to BPH sucking, we suppose that the protein P40 is related to the interaction responses of lice plants to BPH infestation.展开更多
[Objective] The research aimed to establish the two-dimensional electrophoresis（2-DE）technology which was suitable for the rapeseed proteome research.[Method] Xiangyou 17 was as the material.The sample preparation m...[Objective] The research aimed to establish the two-dimensional electrophoresis（2-DE）technology which was suitable for the rapeseed proteome research.[Method] Xiangyou 17 was as the material.The sample preparation method,gel concentration and loading amount,etc.in 2-DE technology were optimized.[Result] The best extraction method of total protein of rapeseed was TCA-acetone method,and the protein spots on 2-DE map were the most.When IPG strip（pH 3-10）and 12% gel were used,and the loading amount was 250 μg,the two-dimensional electrophoresis map with the clear background,good repeatability and high protein spot resolution was obtained.[Conclusion] The research laid the foundation for carrying out the rapeseed proteomics research.展开更多
As a new structure of solid matter quasicrystal brings profound new ideas to the traditional condensed matter physics, its elastic equations are more complicated than that of traditional crystal. A contact problem of ...As a new structure of solid matter quasicrystal brings profound new ideas to the traditional condensed matter physics, its elastic equations are more complicated than that of traditional crystal. A contact problem of decagonal two? dimensional quasicrystal material under the action of a rigid flat die is solved satisfactorily by introducing displacement function and using Fourier analysis and dual integral equations theory, and the analytical expressions of stress and displacement fields of the contact problem are achieved. The results show that if the contact displacement is a constant in the contact zone, the vertical contact stress has order -1/2 singularity on the edge of contact zone, which provides the important mechanics parameter for contact deformation of the quasicrystal.展开更多
To consider the reliability and performance of electronic devices based on polyimide derivatives, dynamic water sorption and diffusion behavior in a polyimide derivative： poly（4＇4 oxydiphenylene pyromellitimide） ...To consider the reliability and performance of electronic devices based on polyimide derivatives, dynamic water sorption and diffusion behavior in a polyimide derivative： poly（4＇4 oxydiphenylene pyromellitimide） （PMDA-ODA）/silica nanocomposite was investigated by two-dimensional ATR-FTIR spectroscopy, by which three states of water molecules owning different H-bonding strength were distinguished. The amounts and strength of H-bonding also played a significant role in determining the diffusion rate of the different states of water molecules. The type of aggregated water molecules which also formed H-bonding with silicic acid （residues） or polyimide system was the last one diffusing to the polymer side in contact with the ATR crystal element because the polymeric matrix blocked their diffusion to a great extent. The diffusion coefficient was also estimated to gain the information of the dynamic diffusion behavior.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(WUT:2024IVA052 and Grant No.104972025KFYjc0089)。
文摘Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051,ZR2025QB50)+6 种基金Guangdong Basic and Applied Basic Research Foundation(2025A1515011191)the Shanghai Sailing Program(23YF1402200,23YF1402400)funded by Basic Research Program of Jiangsu(BK20240424)Open Research Fund of State Key Laboratory of Crystal Materials(KF2406)Taishan Scholar Foundation of Shandong Province(tsqn202408006,tsqn202507058)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University。
文摘As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.
文摘A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property.
基金supported by the Shihezi University High-Level Talents Research Startup Project(Project No.RCZK202521)the National Natural Science Foundation of China(Grant Nos.12271066,11871121,12171405)+1 种基金the Chongqing Natural Science Foundation Joint Fund for Innovation and Development Project(Project No.CSTB2024NSCQLZX0085)the Chongqing Normal University Foundation(Grant No.23XLB018).
文摘This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem.
基金Supported by National Natural Science Foundation of China(Grant No.52205072).
文摘Owing to their rolling friction,two-dimensional piston pumps are highly suitable as power components for electro-hydrostatic actuators(EHAs).These pumps are particularly advantageous for applications requiring high efficiency and reliability.However,the ambiguity surrounding the output flow characteristics of individual two-dimensional pumps poses a significant challenge in achieving precise closed-loop control of the EHA positions.To address this issue,this study established a comprehensive numerical model that included gap leakage to analyze the impact of leakage on the output flow characteristics of a two-dimensional piston pump.The validity of the numerical analysis was indirectly confirmed through meticulous measurements of the leakage and volumetric efficiency,ensuring robust results.The research findings indicated that,at lower pump speeds,leakage significantly affected the output flow rate,leading to potential inefficiencies in the system.Conversely,at higher rotational speeds,the impact of leakage was less pronounced,implying that the influence of leakage on the pump outlet flow must be carefully considered and managed for EHAs to perform position servo control.Additionally,the research demonstrates that two-dimensional motion does not have a unique or additional effect on pump leakage,thus simplifying the design considerations.Finally,the study concluded that maintaining an oil-filled leakage environment is beneficial because it helps reduce the impact of leakage and enhances the overall volumetric efficiency of the pump system.
文摘The pursuit of sustainable hydrogen production has positioned water electrolysis as a cornerstone technology for global carbon neutrality.However,sluggish kinetics,catalyst scarcity,and system integration challenges hinder its widespread deployment.Ultrathin two-dimensional(2D)materials,with their atomically exposed surfaces,tunable electronic structures,and defect-engineering capabilities,present unique opportunities for next-generation electrocatalysts.This review provides an integrated overview of ultrathin 2D electrocatalysts,discussing their structural diversity,synthetic routes,structure-activity relationships,and mechanistic understanding in water electrolysis processes.Special focus is placed on the translation of 2D materials from laboratory research to practical device implementation,emphasizing challenges such as scalable fabrication,interfacial engineering,and operational durability in realistic electrolyzer environments.The role of advanced characterization techniques in capturing dynamic structural changes and active site evolution is discussed.Finally,we outline future research directions,emphasizing the synergy of machine learning-driven materials discovery,advanced operando characterization,and scalable system integration to accelerate the industrial translation of 2D electrocatalysts for green hydrogen production.
基金supported by National Natural Science Foundation of China(72288101,72361137002,and 72101018)the Dutch Research Council(NWO Grant 482.22.01).
文摘Vehicle electrification,an important method for reducing carbon emissions from road transport,has been promoted globally.In this study,we analyze how individuals adapt to this transition in transportation and its subsequent impact on urban structure.Considering the varying travel costs associated with electric and fuel vehicles,we analyze the dynamic choices of households concerning house locations and vehicle types in a two-dimensional monocentric city.A spatial equilibrium is developed to model the interactions between urban density,vehicle age and vehicle type.An agent-based microeconomic residential choice model dynamically coupled with a house rent market is developed to analyze household choices of home locations and vehicle energy types,considering vehicle ages and competition for public charging piles.Key findings from our proposed models show that the proportion of electric vehicles(EVs)peaks at over 50%by the end of the first scrappage period,accompanied by more than a 40%increase in commuting distance and time compared to the scenario with only fuel vehicles.Simulation experiments on a theoretical grid indicate that heterogeneity-induced residential segregation can lead to urban sprawl and congestion.Furthermore,households with EVs tend to be located farther from the city center,and an increase in EV ownership contributes to urban expansion.Our study provides insights into how individuals adapt to EV transitions and the resulting impacts on home locations and land use changes.It offers a novel perspective on the dynamic interactions between EV adoption and urban development.
基金supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2020MA092)the Innovation Project for Graduate Students of Ludong University(Grant No.IPGS2024-048).
文摘The diffusion trajectory of a Brownian particle passing over the saddle point of a two-dimensional quadratic potential energy surface is tracked in detail according to the deep learning strategies.Generative adversarial networks(GANs)emanating in the category of machine learning(ML)frameworks are used to generate and assess the rationality of the data.While their optimization is based on the long short-term memory(LSTM)strategies.In addition to drawing a heat map,the optimal path of two-dimensional(2D)diffusion is simultaneously demonstrated in a stereoscopic space.The results of our simulation are completely consistent with the previous theoretical predictions.
基金financially supported by the National Key R&D Program of China(No.2023YFE0210800)the National Natural Science Foundation of China(Nos.52202171,22350003,and U21A2069)+2 种基金the Hubei Provincial Natural Science Foundation of China(No.2024AFA012)the Shenzhen Science and Technology Program(Nos.JCYJ20240813153403005 and JCYJ20220818102215033)the Guangdong Basic and Applied Basic Research Foundation(No.2023B1515120041).
文摘Two-dimensional(2D)semiconductors have emerged as an ideal platform for fundamental research and a promising candidate beyond silicon materials in future transistors due to their ultrathin thickness and excellent electrical properties.However,the practical application of 2D semiconductors still faces significant challenges.The excellent interface quality of traditional silicon-based semiconductor devices is crucial for their outstanding performance,whereas the interface issues in 2D semiconductor/dielectric systems remain unresolved,resulting in device performance far below expectations.Therefore,further study of the interface in 2D semiconductor/dielectric systems and finding appropriate methods to quantify interface quality,as well as interface optimization strategies,are critical for driving the practical application of 2D semiconductors.In this review,we discuss the issues existing at the 2D semiconductor/dielectric interface,quantitative characterization methods and optimization strategies for interface quality.This includes comparing the advantages and disadvantages of traditional characterization methods for silicon-based semiconductors when applied to 2D semiconductors,as well as the development of strategies to improve interface quality and enhance the performance of 2D devices.Finally,in the outlook,we outline the development directions for improving the interface quality of 2D semiconductor/dielectric systems.
基金Project supported by the National Key R&D Program of China (Grant No. 2019YFA0307800)the National Natural Science Foundation of China (Grant No. 12074377)+2 种基金Fundamental Research Funds for the Central Universities,the International Partnership Program of Chinese Academy of Sciences (Grant No. 211211KYSB20210007)the China Postdoctoral Science Foundation (Grant No. 2024M753465)the Postdoctoral Fellowship Program (Grade C) of China Postdoctoral Science Foundation (Grant No. GZC20241893)。
文摘Moiré superlattices have revolutionized the study of two-dimensional materials, enabling unprecedented control over their electronic, magnetic, optical, and mechanical properties. This review provides a comprehensive analysis of the latest advancements in moiré physics, focusing on the formation of moiré superlattices due to rotational misalignment or lattice mismatch in two-dimensional materials. These superlattices induce flat band structures and strong correlation effects,leading to the emergence of exotic quantum phases, such as unconventional superconductivity, correlated insulating states,and fractional quantum anomalous Hall effects. The review also explores the underlying mechanisms of these phenomena and discusses the potential technological applications of moiré physics, offering insights into future research directions in this rapidly evolving field.
基金supported by the National Key Projects for Fundamental Research and Development of China(2021YFA1500803)the National Natural Science Foundation of China(51825205,52120105002,22088102,22279150,22209186)+1 种基金the Beijing Natural Science Foundation(2222080)the Youth Innovation Promotion Association of the CAS(Y2021011)。
文摘Hydrogen evolution reaction(HER)plays a crucial role in developing clean and renewable hydrogen energy technologies.However,conventional HER catalysts rely on expensive and scarce noble metals,which is a significant challenge for practical application.Recently,twodimensional transition metal dichalcogenides(2D-TMDs)have emerged as attractive and cost-effective alternatives for efficient electrocatalysis in the HER.Substantial efforts have been dedicated to advancing the synthesis and application of 2D-TMDs.This review highlights the design and synthesis of high-performance 2D-TMDs-based HER electrocatalysts by combining theoretical calculations with experimental methods.Subsequently,recent advances in synthesizing different types of 2D TMDs with enhanced HER activity are summarized.Finally,the conclusion and perspectives of the 2D TMDs-based HER electrocatalysts are discussed.We expect that this review will provide new insights into the design and development of highly efficient 2D TMDs-based HER electrocatalysts for industrial applications.
基金supported by the National Natural Science Foundation of China(Nos.52371203,51971221 and 52031014).
文摘Organic magnetic semiconductors have aroused much attention for spintronic applications. However, it remains challenging to achieve organic semiconductors with strong room-temperature ferromagnetism. Here, we report a two-dimensional (2D) tetragonal organic-inorganic ferrimagnetic (FIM) semiconductor of Fe_(14)Se_(16)(peha)_(0.7) (peha = pentaethylenehexamine) with excellent thermal stability and a Curie temperature (T_(C)) higher than 519 K. Magnetic and Mössbauer measurements reveal a long-range magnetic ordering in single crystalline Fe_(14)Se_(16)(peha)0.7 nanosheets. The saturation magnetization and coercivity are 5.9 emu g^(−1) and 0.42 kOe at 5 K, which slightly reduces to 4.6 emu g^(−1) and ∼0 Oe at 300 K. A direct optical bandgap of 2.22 eV is obtained by tuning electronic structure of β-Fe3Se4 host layers through spacer layers consisting of Fe^(3+) and peha. Electrical and Seebeck coefficient data indicate that the n-type semiconductor follows the thermally-activated conduction mechanism (lnρ ∝ T^(−1)) in a range of 130–300 K with an activation energy (Ea) of 62.69 meV. Thermal conductivity is 2.5 W m^(−1) K^(−1) at 300 K, while the Wiedemann–Franz law is strongly violated according to electrical-thermal transport data due to weak incorporation of organic spacer layers and host layers. This study sets the stage for exploiting new room-temperature organic magnetic semiconductor systems for spintronic materials.
基金supported by the National Natural Science Foundation of China(Nos.52172291,52122312,and 52473294)'Shuguang Program'supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.22SG31)the State Key Laboratory for Advanced Fiber Materials,Donghua University
文摘Excessive nitrogen emission caused by human activities has significantly disrupted the global nitrogen cycle,adversely affecting ecosystems and human health.Electrocatalytic nitrate reduction to valuable ammonia(eNRA)presents an encouraging alternative marked by mild reaction conditions,rapid reaction rates,and minimal byproduct pollution,successfully overcoming the challenges of the energy-intensive Haber-Bosch process.Recent innovations in two-dimensional(2D)electrocatalysts have emerged as a promising approach to enhance the efficiency and selectivity of this transformation.This review systematically examines the latest advancements in2D materials,including metals,metal compounds,nonmetallic elements,and organic frameworks,highlighting their unique electronic properties and high surface area that facilitate the electrocatalytic reactions.We explore strategies to optimize these catalysts,such as doping,heterostructure,and surface functionalization,which have shown significant improvements in catalytic performance.Furthermore,the role of in situ/operando characterization techniques in understanding the reaction mechanisms is highlighted,aiming to provide both theoretical and practical insights for the research and development of 2D nanoelectrocatalysts during eNRA.Additionally,future perspectives and ongoing challenges are discussed to offer insights for transitioning from experimental investigations to real-world applications.
基金supported by the National Key Research and Development Program of China(Grant No.2024YFE0205000)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20243037)+2 种基金the National Natural Science Foundation of China(Grant Nos.62074077 and 61921005)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20231098)the Collab-orative Innovation Center of Solid State Lighting and Energy-Saving Electronics.
文摘Polarization-induced two-dimensional hole gases(2DHG)in GaN/AlGaN/GaN heterostructures offer a promising pathway for advancing p-channel transistors.This work investigates the impact of p-GaN thickness on hole distribution and transport through temperature-dependent Hall measurements and TCAD simulations.It is demonstrated that the p-channel is composed of holes both in the p-GaN layer and in the 2DHG at the GaN/AlGaN heterointerface at 300 K,whereas at 77 K,the p-channel conduction is dominated solely by the 2DHG at the GaN/AlGaN heterointerface.The results also reveal the formation of a polarization-induced 2DHG at the GaN/AlGaN interface,exhibiting a high sheet density of 2.2×10^(13)cm^(-2)and a mobility of 16.2 cm^(2)·V^(-1)·s^(-1)at 300 K.The 2DHG sheet density remains nearly independent of p-GaN thickness when the p-GaN layer exceeds 30 nm.However,for p-GaN layers thinner than 30 nm,the 2DHG sheet density strongly depends on the p-GaN thickness,which is attributed to the gradual extension of the depletion region toward the GaN/AlGaN interface under the influence of surface trap states.
基金Supported by Guangdong Medical Science and Technology Research Fund Project,No.A2024475.
文摘This study explores the significance of using two-dimensional shear wave elastography(2D-SWE)to assess liver stiffness(LS)and spleen area(SPA)for predicting post-hepatectomy liver failure(PHLF).By providing a non-invasive method to measure LS,which correlates with the degree of liver fibrosis,and SPA,an indicator of portal hypertension,2D-SWE offers a comprehensive evaluation of a patient’s hepatic status.These advancements are particularly crucial in hepatic surgery,where accurate preoperative assessments are essential for optimizing surgical outcomes and minimizing complications.This letter highlights the prac-tical implications of integrating 2D-SWE into clinical practice,emphasizing its potential to improve patient safety and surgical precision by enhancing the ability to predict PHLF and tailor surgical approaches accordingly.
文摘A recombinant inbred population (RI) was constructed from a cross between B5, an introgression. line from the wild rice Oryza officinalis Wall. ex Watt, and susceptible cultivar Minghui 63 ( O. sativa L.). The brown planthopper ( BPH) resistances of RI lines were evaluated. Based on bulked segregant analysis (BSA), two protein bulks were made by extracting proteins from equally mixed seedlings of extremely resistant and susceptible plants selected from the RI population, respectively. Two-dimensional electrophoresis was used to detect the changes of polypeptide pattern. Results showed that a protein P40 ( pI 6.3, Mw 40 kD) was significantly reduced or vanished after BPH infestation for 48 h in the susceptible bulk, while it remained uninfluenced in the resistant bulk. In connection with the physiological changes of the resistant and susceptible lines subjected to BPH sucking, we suppose that the protein P40 is related to the interaction responses of lice plants to BPH infestation.
基金Supported by National 863 Project(2010AA101503)National Science and Technology Support Planning Item(2006BAD05A12)Student Innovation Fund Item of Hefei University of Technology(XS2010100)~~
文摘[Objective] The research aimed to establish the two-dimensional electrophoresis（2-DE）technology which was suitable for the rapeseed proteome research.[Method] Xiangyou 17 was as the material.The sample preparation method,gel concentration and loading amount,etc.in 2-DE technology were optimized.[Result] The best extraction method of total protein of rapeseed was TCA-acetone method,and the protein spots on 2-DE map were the most.When IPG strip（pH 3-10）and 12% gel were used,and the loading amount was 250 μg,the two-dimensional electrophoresis map with the clear background,good repeatability and high protein spot resolution was obtained.[Conclusion] The research laid the foundation for carrying out the rapeseed proteomics research.
文摘As a new structure of solid matter quasicrystal brings profound new ideas to the traditional condensed matter physics, its elastic equations are more complicated than that of traditional crystal. A contact problem of decagonal two? dimensional quasicrystal material under the action of a rigid flat die is solved satisfactorily by introducing displacement function and using Fourier analysis and dual integral equations theory, and the analytical expressions of stress and displacement fields of the contact problem are achieved. The results show that if the contact displacement is a constant in the contact zone, the vertical contact stress has order -1/2 singularity on the edge of contact zone, which provides the important mechanics parameter for contact deformation of the quasicrystal.
基金supported by the National Natural Science Foundation of China(No.20573022,No.20425415)the National Basic Research Pro-gram of China(2005CB623800),the PHD Program of M0E(20050246010)the"Qimingxing"Project(No.04QM1402)of Shanghai Municipal Science and Technology Commission,and the"Shuguang"Project(No.01SG05)of the Shanghai Municipal Education Commission and Shanghai Education Development Foundation.
文摘To consider the reliability and performance of electronic devices based on polyimide derivatives, dynamic water sorption and diffusion behavior in a polyimide derivative： poly（4＇4 oxydiphenylene pyromellitimide） （PMDA-ODA）/silica nanocomposite was investigated by two-dimensional ATR-FTIR spectroscopy, by which three states of water molecules owning different H-bonding strength were distinguished. The amounts and strength of H-bonding also played a significant role in determining the diffusion rate of the different states of water molecules. The type of aggregated water molecules which also formed H-bonding with silicic acid （residues） or polyimide system was the last one diffusing to the polymer side in contact with the ATR crystal element because the polymeric matrix blocked their diffusion to a great extent. The diffusion coefficient was also estimated to gain the information of the dynamic diffusion behavior.
