Flooding is the most famous technique for locating contents in unstructured P2P networks. Recently traditional flooding has been replaced by more efficient dynamic query （DQ） and different variants of such algorithm...Flooding is the most famous technique for locating contents in unstructured P2P networks. Recently traditional flooding has been replaced by more efficient dynamic query （DQ） and different variants of such algorithms. Dynamic query is a new flooding technique which could estimate a proper time-to-live （TTL） value for a query flooding by estimating the popularity of the searched files, and retrieve sufficient results under controlled flooding range for reducing network traffic. However, all DQ-like search algorithms are ＂blind＂ so that a large amount of redundant messages are caused. In this paper, we proposed a new search scheme, called Immune Search Scheme （ISS）, to cope with this problem. In ISS, an immune systems inspired concept of similarity-governed clone proliferation and mutation for query message movement is applied. Some assistant strategies, that is, shortcuts creation and peer traveling are incorporated into ISS to develop ＂immune memory＂ for improving search performance, which can make ISS not be blind but heuristic.展开更多
Passive worms can passively propagate through embedding themselves into some sharing files, which can result in significant damage to unstructured P2P networks. To study the passive worm behaviors, this paper firstly ...Passive worms can passively propagate through embedding themselves into some sharing files, which can result in significant damage to unstructured P2P networks. To study the passive worm behaviors, this paper firstly analyzes and obtains the average delay for all peers in the whole transmitting process due to the limitation of network throughput, and then proposes a mathematical model for the propagation of passive worms over the unstructured P2P networks. The model mainly takes the effect of the network throughput into account, and applies a new healthy files dissemination-based defense strategy according to the file popularity which follows the Zipf distribution. The simulation results show that the propagation of passive worms is mainly governed by the number of hops, initially infected files and uninfected files. The larger the number of hops, the more rapidly the passive worms propagate. If the number of the initially infected files is increased by the attackers, the propagation speed of passive worms increases obviously. A larger size of the uninfected file results in a better attack performance. However, the number of files generated by passive worms is not an important factor governing the propagation of passive worms. The effectiveness of healthy files dissemination strategy is verified. This model can provide a guideline in the control of unstructured P2P networks as well as passive worm defense.展开更多
Although anonymizing Peer-to-Peer （P2P） networks often means extra cost in terms of transfer efficiency, many systems try to mask the identities of their users for privacy consideration. By comparison and analysis o...Although anonymizing Peer-to-Peer （P2P） networks often means extra cost in terms of transfer efficiency, many systems try to mask the identities of their users for privacy consideration. By comparison and analysis of existing approaches, we investigate the properties of unstructured P2P anonymity, and summarize current attack models on these designs. Most of these approaches are path-based, which require peers to pre-construct anonymous paths before transmission, thus suffering significant overhead and poor reliability. We also discuss the open problems in this field and propose several future research directions.展开更多
It is universally acknowledged by network security experts that proactive peer-to-peer (P2P) worms may soon en-gender serious threats to the Internet infrastructures. These latent threats stimulate activities of model...It is universally acknowledged by network security experts that proactive peer-to-peer (P2P) worms may soon en-gender serious threats to the Internet infrastructures. These latent threats stimulate activities of modeling and analysis of the proactive P2P worm propagation. Based on the classical two-factor model,in this paper,we propose a novel proactive worm propagation model in unstructured P2P networks (called the four-factor model) by considering four factors:(1) network topology,(2) countermeasures taken by Internet service providers (ISPs) and users,(3) configuration diversity of nodes in the P2P network,and (4) attack and defense strategies. Simulations and experiments show that proactive P2P worms can be slowed down by two ways:improvement of the configuration diversity of the P2P network and using powerful rules to reinforce the most connected nodes from being compromised. The four-factor model provides a better description and prediction of the proactive P2P worm propagation.展开更多
Distributed network architecture and dynamic change of nodes makes the operation of structured peer-to-peer networks unpredictable. This article aims to present a research on the running rule of structured peer-to-pee...Distributed network architecture and dynamic change of nodes makes the operation of structured peer-to-peer networks unpredictable. This article aims to present a research on the running rule of structured peer-to-peer networks through a mathematical model. The proposed model provides a low-complexity means to estimate the performance of a structured peer-to-peer network from two aspects： the average existent time of a node and probability of returning to a temporarily steady state of network. On the basis of the results, it can be concluded that the proposed structured peer-to-peer network is suitable for those conditions where the frequency of node change is under limited value, and this value mainly depends on the initializing time of the node. Otherwise, structured peer-to-peer network can be abstracted as a network queuing system, which is composed of many node queuing systems in a meshy way and the relation between the throughput of the node system and network system is analyzed.展开更多
The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-...The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.展开更多
The surge of distributed renewable energy resources has given rise to the emergence of prosumers,facilitating the low-carbon transition of distribution networks.However,flexible prosumers introduce bidirectional power...The surge of distributed renewable energy resources has given rise to the emergence of prosumers,facilitating the low-carbon transition of distribution networks.However,flexible prosumers introduce bidirectional power and carbon interaction,increasing the complexity of practical decision-making in distribution networks.To address these challenges,this paper presents a carbon-coupled network charge-guided bi-level interactive optimization method between the distribution system operator and prosumers.In the upper level,a carbon-emission responsibility settlement method that incorporates the impact of peer-to-peer(P2P)trading is proposed,based on a carbon-emission flow model and optimal power flow model,leading to the formulation of carbon-coupled network charges.In the lower level,a decentralized P2P trading mechanism is developed to achieve the clearing of energy and carbon-emission rights.Furthermore,an alternating direction method of multipliers with an adaptive penalty factor is introduced to address the equilibrium of the P2P electricity–carbon coupled market,and an improved bisection method is employed to ensure the convergence of the bi-level interaction.A case study on the modified IEEE 33-bus system demonstrates the effectiveness of the proposed model and methodology.展开更多
Enterprise applications utilize relational databases and structured business processes, requiring slow and expensive conversion of inputs and outputs, from business documents such as invoices, purchase orders, and rec...Enterprise applications utilize relational databases and structured business processes, requiring slow and expensive conversion of inputs and outputs, from business documents such as invoices, purchase orders, and receipts, into known templates and schemas before processing. We propose a new LLM Agent-based intelligent data extraction, transformation, and load (IntelligentETL) pipeline that not only ingests PDFs and detects inputs within it but also addresses the extraction of structured and unstructured data by developing tools that most efficiently and securely deal with respective data types. We study the efficiency of our proposed pipeline and compare it with enterprise solutions that also utilize LLMs. We establish the supremacy in timely and accurate data extraction and transformation capabilities of our approach for analyzing the data from varied sources based on nested and/or interlinked input constraints.展开更多
Addressing the kinetic limitations of oxygen evolution reaction(OER)is paramount for advancing rechargeable Zn-air batteries,thus it is extremely urgent to drive the development of effective and affordable electrocata...Addressing the kinetic limitations of oxygen evolution reaction(OER)is paramount for advancing rechargeable Zn-air batteries,thus it is extremely urgent to drive the development of effective and affordable electrocatalysts.This work constructs the interfacial structure of cobalt-iron alloys@phosphates(denoted as CoFe/CoFePO)as OER catalyst through a two-step approach using water-bath and hydrothermal methods,which demonstrated significant OER activity in alkaline media,requiring a low overpotential of 271 mV to achieve 10 mA cm^(−2) and exhibiting a competitive Tafel slope of 65 mV dec^(-1),alongside sustained operational stability.The enhanced performance can be attributed to the improved electrical conductivity due to the participation of CoFe alloys and the increased number of active sites through partial phosphorylation,which synergistically enhances charge transfer processes and accelerates OER kinetics.Moreover,dynamic structural evolution during OER process was thoroughly probed,and the results show that alloys@phosphates gradually evolve into phosphate radicalmodified CoFe hydroxyoxides that act as the actual active phase.Highlighting its practical applicability,the integration of prepared catalyst into zinc-air batteries leads to markedly improved performance,thereby offering promising new strategic directions for the development of next-generation OER electrocatalysts.展开更多
In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalabilit...In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalability through modular design.However,traditional manufacturing processes are limited by mold dependence,organic solvent toxicity,and insufficient molding capability for complex structures,resulting in difficulty achieving precise regulation of cross-scale pores.Additive manufacturing(AM)technology employs a digital layered molding strategy to achieve the cross-scale structural regulation of catalysts from macroscopic flow channels to mesopores and micropores.This paper summarizes recent advances in the structural design of monolithic catalysts enabled by AM technologies and highlights their emerging applications in catalytic processes.Structurally,AM-fabricated monoliths have been effectively employed in key chemical reactions such as fuel reforming,CO_(2)conversion,biofuel synthesis.Strategies such as geometrical topology optimization,multi-scale pore synergy,biomimetic structural design,and functional gradient integration have been utilized to enhance heat and mass transport,reduce pressure drops,and improve overall catalytic performance.By overcoming the limitations of traditional catalysts,AM technologies create a new paradigm for addressing the longstanding challenge of coupling mass transfer with reaction kinetics.This approach provides a feasible pathway for driving both theoretical innovation and practical implementation of high-efficiency catalytic systems.展开更多
One-dimensional nanomaterials with hollow structures could provide large space for ion storage and charge accumulation.Herein,TiO_(2)/MoSe_(2)-Carbon nanotube composite(NT)materials were designed and fabricated by the...One-dimensional nanomaterials with hollow structures could provide large space for ion storage and charge accumulation.Herein,TiO_(2)/MoSe_(2)-Carbon nanotube composite(NT)materials were designed and fabricated by the template method and the chelation coordination reaction.The stability and conductivity were improved by the presence of titanium and hollow tubular-architecture carbon in the whole structure.As a result,the as-prepared TiO_(2)/MoSe_(2)-Carbon hybrid achieved a high-rate performance of 760.0 mAh·g^(−1) at a current density of 0.1 A·g^(−1),while still obtaining stability after 300 charge/discharge cycles.The enhancement of the lithium storage capacity mainly contributed to the acceleration of the electron conductivity and the storage kinetics.Moreover,the hollow structure reduced the volume strain and stress caused by the rapid insertion and removal of lithium ions,which ensured the favorable stability of lithium storage.The experiment shows that the kinetic of the TiO_(2)/MoSe_(2)-carbon hybrid during the lithium storage process is dominated by the pseudocapacitance mechanism.This work provides a new idea and scheme for the design and preparation of hierarchical nanotube composite electrode materials.展开更多
With the rapid development of flexible equipment,high-energy/-power requirements have been proposed for energy storage devices.Nevertheless,the poor conductivities of metallic oxides and their low levels of transmissi...With the rapid development of flexible equipment,high-energy/-power requirements have been proposed for energy storage devices.Nevertheless,the poor conductivities of metallic oxides and their low levels of transmission of electrons/ions hinder their widespread application.Here,a sandwich-structured Co_(3)O_(4)-Fe_(3)O_(4)(CFO) composite with binder-free was synthesized on a carbon cloth substrate via co-precipitation and partial ion exchange.The appropriate substitution of Co_(3)O_(4)with Fe_(3)O_(4)is favorable in promoting the rapid transfer of electrolyte ions and alleviating changes in volume during the electrochemical studies.When the duration of the substitution reaction is 20 min,the obtained electrode delivers a maximum specific capacitance of 1196.2 Fg^(-1)at a current density of 1 A g^(-1)and a superior capacity retention of~71%when the current density varies from 1to 30 Ag^(-1).Furthermore,the fabricated CFO//activated carbon flexible all-solid-state supercapacitor exhibits arespective maximum energy and power density of 68.7Wh kg^(-1)and 16,000 W kg^(-1)and excellent flexibility.It also displays a specific capacity retention of 81.3%under four continuous bending states at a current density of 6A g^(-1)over 10,000 cycles.These remarkable electrochemical char ac teristics suggest that the sandwich-structured CFO composite displays considerable potential for application in flexible high-energy/-power supercapacitors.展开更多
Endowing stimuli-responsive materials with micro-nano structures is an intriguing strategy for the fabrication of superwetting surfaces;however,its application is limited by poor chemical/mechanical stability.Herein,a...Endowing stimuli-responsive materials with micro-nano structures is an intriguing strategy for the fabrication of superwetting surfaces;however,its application is limited by poor chemical/mechanical stability.Herein,a simple and versatile strategy was developed to fabricate durable polymeric superwetting surfaces with photoswitchable wettability on hierarchically structured metallic substrates.Inspired by nature,a novel functional terpolymer incorporating mussel-inspired catechol groups,photoresponsive azobenzene groups,and low-surface-energy fluorine-containing groups was synthesized via solution radical polymerization.The azobenzene-containing terpolymer possesses outstanding photoresponsiveness in both the solution and film states because of the trans-cis isomerization of the azobenzene moieties.After dip-coating with the mussel-inspired azo-copolymer,the as-prepared smart surfaces exhibited a photo-triggered change in wettability between high hydrophobicity and superhydrophilicity.More importantly,these superwetting surfaces with enhanced adhesion properties can tolerate harsh environmental conditions and repeated abrasion tests,thereby demonstrating excellent chemical robustness and mechanical durability.This study paves a new avenue for the convenient and large-scale fabrication of robust smart surfaces that could find widespread potential applications in microfluidic devices,water treatment,and functional coatings.展开更多
The novel generation of clean energy has captured substantial public interest as the ecological environment deteriorates and fossil energy sources become depleted,with electrochemical catalysis deemed essential to the...The novel generation of clean energy has captured substantial public interest as the ecological environment deteriorates and fossil energy sources become depleted,with electrochemical catalysis deemed essential to the progress of clean energy technologies.Core-shell nanocomposite materials exhibit excellent chemical erosion resistance and effectively mitigate issues such as nanoparticle aggregation and sintering.Therefore,core-shell electrocatalysts demonstrate considerable advantages,such as enhanced activity and stability,making them widely applicable in electrocatalysis.This review offers an extensive summary of the latest advances,techniques,and applications of core-shell noble metal-based catalysts in electrocatalysis,encompassing a diverse range of synthesis techniques and strategies designed to fine-tune electrocatalytic performance.The article presents techniques such as seed-mediated growth,electrodeposition,template synthesis,and self-assembly and further delves into control strategies for enhancing electrocatalytic performance via case studies,examining electronic and geometric effects,with the former broken down into strain and ligand effects.Next,the article focuses on the remarkable progress achieved by noble metal-based core-shell structures in enhancing the efficiency of key electrocatalytic reactions,such as the hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and carbon dioxide reduction reaction(CO_(2)RR).Finally,the primary challenges and future prospects in this field are discussed,offering insight that will inform further research and development efforts.The primary objective of this review is to illuminate the design and construction of novel core-shell noble metal-based catalysts for energy storage and conversion technologies.展开更多
The accuracy of center height detection for corrugated beam guardrails is significantly affected by robot posture in the mobile highway guardrail detection systems based on structured light vision.To address the probl...The accuracy of center height detection for corrugated beam guardrails is significantly affected by robot posture in the mobile highway guardrail detection systems based on structured light vision.To address the problem,this paper proposes an integrated calibration method for structured light vision sensors.In the proposed system,the sensor is mounted on a crawler-type mobile robot,which scans and measures the center height of guardrails while in motion.However,due to external disturbances such as uneven road surfaces and vehicle vibrations,the posture of the robot may deviate,causing displacement of the sensor platform and resulting in spatial 3D measurement errors.To overcome this issue,the system integrates inertial measurement unit(IMU)data into the sensor calibration process,enabling realtime correction of posture deviations through sensor fusion.This approach achieves a unified calibration of the structured light vision system,effectively compensates for posture-induced errors,and enhances detection accuracy.A prototype was developed and tested in both laboratory and real highway environments.Experimental results demonstrate that the proposed method enables accurate center height detection of guardrails under complex road conditions,significantly reduces posture-related measurement errors,and greatly improves the efficiency and reliability of traditional detection methods.展开更多
Maintaining the s-polarization state of laser beams is important to achieve high modulation depth in a laser-interference-based super-resolution structured illumination microscope(SR-SIM).However,the imperfect optical...Maintaining the s-polarization state of laser beams is important to achieve high modulation depth in a laser-interference-based super-resolution structured illumination microscope(SR-SIM).However,the imperfect optical components can depolarize the laser beams hence degenerating the modulation depth.Here,we first presented a direct measurement method designed to estimate the modulation depth more precisely by shifting illumination patterns with equal phase steps.This measurement method greatly reduces the dependence of modulation depths on the samples,and then developed a polarization optimization method to achieve high modulation depth at all orientations by actively and quantitatively compensating for the additional phase difference using a combination of waveplate and a liquid crystal variable retarder(LCVR).Experimental results demonstrate that our method can achieve illumination patterns with modulation depth higher than 0.94 at three orientations with only one LCVR voltage,which enables isotropic resolution improvement.展开更多
Materials engineering plays a key role in the field of electrochemical energy storage,and considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using ...Materials engineering plays a key role in the field of electrochemical energy storage,and considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using novel functional electrode materials.Materials with hollow structures are of particular interests due to their low density,large specific surface area and high porosity,making them promising candidates for energy conversion and storage.The Kirkendall effect has been widely applied for the synthesis of nanoscale hollow structures,which involves an unbalanced counter diffusion through a reaction interface.Herein,the recent progress on the use of the nanoscale Kirkendall effect to synthesize hollow nanostructures,including nanoparticles,one-dimensional(1-D),two-dimensional(2-D),and three-dimensional(3-D)nanostructures,and their potential applications in energy storage devices are summarized and discussed.And prospects is made for the future development of this research field.展开更多
Quantum entanglement, a fundamental concept in quantum mechanics, lies at the heart of many current and futurequantum technologies. A pivotal task is the generation and control of diverse quantum entangled states in a...Quantum entanglement, a fundamental concept in quantum mechanics, lies at the heart of many current and futurequantum technologies. A pivotal task is the generation and control of diverse quantum entangled states in a more compactand flexible manner. Here, we introduce an approach to achieve diverse path entanglement by exploiting the interactionbetween noncommutative metasurfaces and entangled photons. Different from other path entanglements, ourquantum path entanglement is evolution path entanglement of photons on Poincaré sphere. Due to quantum entanglementbetween idler photons and structured signal photons, evolution path of idler photons on the fundamental Poincarésphere can be nonlocally mirrored by structured signal photons on any higher-order Poincaré sphere, resulting in quantumpath entanglement. Benefiting from noncommutative metasurfaces, diverse quantum path entanglement can beswitched across different higher-order Poincaré spheres using distinct combination sequences of metasurfaces. Ourmethod allows for the tuning of diverse quantum path entanglement across a broad spectrum of quantum states, offeringa significant advancement in the manipulation of quantum entanglement.展开更多
Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems.Herein,we report a novel solution-processed core-shell structured poly-imide(PI)nanoc...Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems.Herein,we report a novel solution-processed core-shell structured poly-imide(PI)nanocomposite with moderate dielectric constant HfO_(2)core and wide-bandgap Al_(2)O_(3)shell,ef-fectively addressing the typical trade-off between dielectric constant and breakdown strength in dielectric nanocomposites predominant at elevated temperatures.The formation of improved dielectrically match-ing interfaces by the rationally designed dielectric constant gradient from core-shell-matrix remarkably mitigates the distortion of the electric field around the interfaces,resulting in a high breakdown strength.Wide band gap Al_(2)O_(3)shell also introduces deeper traps to impede the conduction loss.The validity of Al_(2)O_(3)shell has been proved via experiments and simulations.Accordingly,HfO_(2)@Al_(2)O_(3)/PI nanocompos-ite exhibits an excellent charge-discharge efficiency of 91.7%at 300 MV/m and a maximum discharged energy density of 2.94 J/cm^(3)at 150℃,demonstrating its potential for high-temperature energy storage.展开更多
Hydrogen production coupled with small molecule oxidation derived by renewable energy power has been widely studied as an effective method to reduce energy consumption and prepare added value production.Here,the coppe...Hydrogen production coupled with small molecule oxidation derived by renewable energy power has been widely studied as an effective method to reduce energy consumption and prepare added value production.Here,the copper-cobalt phosphide with a multilevel structure has been designed based on the hard and soft acids and bases theory.The nanocone composed of lamellas presented a sharp tip,which a positive effect on the mass transfer enhanced by a local electric field,and the nanolamellas contain CoP/Cu_(3)P interface provide the highly selective active site for the gluconic acid(GNA)synthesis and hydrogen evolution.The catalyst can drive hydrogen evolution at 5 A·cm^(-2)up to 437 h without active decay,and the electrocatalytic glucose oxidation at anode presents high efficiency due to Cu(I)introduction and the synergetic effect between interfaces.Density functional theory(DFT)calculation shows that water splitting more readily occurs at the CoP,which provides adsorbed H and-OH for hydrogen evolution and glucose oxidation,respectively,and glucose adsorption more readily occurs at the Cu_(3)P,which presents lower conversion energy for high value-added GNA.Efficient hydrogen evolution and glucose conversion indicate its high intrinsic activity and synergetic effect.This work provides a special interface construction strategy for the catalytic conversion of hydrogen and small molecules.展开更多
基金Supported by the National Natural Science Foundation of China (90604012)
文摘Flooding is the most famous technique for locating contents in unstructured P2P networks. Recently traditional flooding has been replaced by more efficient dynamic query （DQ） and different variants of such algorithms. Dynamic query is a new flooding technique which could estimate a proper time-to-live （TTL） value for a query flooding by estimating the popularity of the searched files, and retrieve sufficient results under controlled flooding range for reducing network traffic. However, all DQ-like search algorithms are ＂blind＂ so that a large amount of redundant messages are caused. In this paper, we proposed a new search scheme, called Immune Search Scheme （ISS）, to cope with this problem. In ISS, an immune systems inspired concept of similarity-governed clone proliferation and mutation for query message movement is applied. Some assistant strategies, that is, shortcuts creation and peer traveling are incorporated into ISS to develop ＂immune memory＂ for improving search performance, which can make ISS not be blind but heuristic.
基金National Natural Science Foundation of China (No.60633020 and No. 90204012)Natural Science Foundation of Hebei Province (No. F2006000177)
文摘Passive worms can passively propagate through embedding themselves into some sharing files, which can result in significant damage to unstructured P2P networks. To study the passive worm behaviors, this paper firstly analyzes and obtains the average delay for all peers in the whole transmitting process due to the limitation of network throughput, and then proposes a mathematical model for the propagation of passive worms over the unstructured P2P networks. The model mainly takes the effect of the network throughput into account, and applies a new healthy files dissemination-based defense strategy according to the file popularity which follows the Zipf distribution. The simulation results show that the propagation of passive worms is mainly governed by the number of hops, initially infected files and uninfected files. The larger the number of hops, the more rapidly the passive worms propagate. If the number of the initially infected files is increased by the attackers, the propagation speed of passive worms increases obviously. A larger size of the uninfected file results in a better attack performance. However, the number of files generated by passive worms is not an important factor governing the propagation of passive worms. The effectiveness of healthy files dissemination strategy is verified. This model can provide a guideline in the control of unstructured P2P networks as well as passive worm defense.
文摘Although anonymizing Peer-to-Peer （P2P） networks often means extra cost in terms of transfer efficiency, many systems try to mask the identities of their users for privacy consideration. By comparison and analysis of existing approaches, we investigate the properties of unstructured P2P anonymity, and summarize current attack models on these designs. Most of these approaches are path-based, which require peers to pre-construct anonymous paths before transmission, thus suffering significant overhead and poor reliability. We also discuss the open problems in this field and propose several future research directions.
基金Project (No. 09511501600) partially supported by the Science and Technology Commission of Shanghai Municipality, China
文摘It is universally acknowledged by network security experts that proactive peer-to-peer (P2P) worms may soon en-gender serious threats to the Internet infrastructures. These latent threats stimulate activities of modeling and analysis of the proactive P2P worm propagation. Based on the classical two-factor model,in this paper,we propose a novel proactive worm propagation model in unstructured P2P networks (called the four-factor model) by considering four factors:(1) network topology,(2) countermeasures taken by Internet service providers (ISPs) and users,(3) configuration diversity of nodes in the P2P network,and (4) attack and defense strategies. Simulations and experiments show that proactive P2P worms can be slowed down by two ways:improvement of the configuration diversity of the P2P network and using powerful rules to reinforce the most connected nodes from being compromised. The four-factor model provides a better description and prediction of the proactive P2P worm propagation.
文摘Distributed network architecture and dynamic change of nodes makes the operation of structured peer-to-peer networks unpredictable. This article aims to present a research on the running rule of structured peer-to-peer networks through a mathematical model. The proposed model provides a low-complexity means to estimate the performance of a structured peer-to-peer network from two aspects： the average existent time of a node and probability of returning to a temporarily steady state of network. On the basis of the results, it can be concluded that the proposed structured peer-to-peer network is suitable for those conditions where the frequency of node change is under limited value, and this value mainly depends on the initializing time of the node. Otherwise, structured peer-to-peer network can be abstracted as a network queuing system, which is composed of many node queuing systems in a meshy way and the relation between the throughput of the node system and network system is analyzed.
基金sponsored by the National Natural Science Foundation of China(Nos.5210125 and 52375422)the Science Research Project of Hebei Education Department(No.BJK2023058)the Natural Science Foundation of Hebei Province(Nos.E2020208069,B2020208083 and E202320801).
文摘The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.
基金supported by Institutional Research Fund from Sichuan University(0-1 Innovation Research Project,2023SCUH0002)the Sichuan Science and Technology Program(2024YFHZ0312)+1 种基金the Chengdu Science and Technology Program(2024YF0600012HZ)the National Natural Science Foundation of China(U2166211 and 52177103).
文摘The surge of distributed renewable energy resources has given rise to the emergence of prosumers,facilitating the low-carbon transition of distribution networks.However,flexible prosumers introduce bidirectional power and carbon interaction,increasing the complexity of practical decision-making in distribution networks.To address these challenges,this paper presents a carbon-coupled network charge-guided bi-level interactive optimization method between the distribution system operator and prosumers.In the upper level,a carbon-emission responsibility settlement method that incorporates the impact of peer-to-peer(P2P)trading is proposed,based on a carbon-emission flow model and optimal power flow model,leading to the formulation of carbon-coupled network charges.In the lower level,a decentralized P2P trading mechanism is developed to achieve the clearing of energy and carbon-emission rights.Furthermore,an alternating direction method of multipliers with an adaptive penalty factor is introduced to address the equilibrium of the P2P electricity–carbon coupled market,and an improved bisection method is employed to ensure the convergence of the bi-level interaction.A case study on the modified IEEE 33-bus system demonstrates the effectiveness of the proposed model and methodology.
文摘Enterprise applications utilize relational databases and structured business processes, requiring slow and expensive conversion of inputs and outputs, from business documents such as invoices, purchase orders, and receipts, into known templates and schemas before processing. We propose a new LLM Agent-based intelligent data extraction, transformation, and load (IntelligentETL) pipeline that not only ingests PDFs and detects inputs within it but also addresses the extraction of structured and unstructured data by developing tools that most efficiently and securely deal with respective data types. We study the efficiency of our proposed pipeline and compare it with enterprise solutions that also utilize LLMs. We establish the supremacy in timely and accurate data extraction and transformation capabilities of our approach for analyzing the data from varied sources based on nested and/or interlinked input constraints.
基金supported by the National Natural Science Foundation of China(No.52002122).
文摘Addressing the kinetic limitations of oxygen evolution reaction(OER)is paramount for advancing rechargeable Zn-air batteries,thus it is extremely urgent to drive the development of effective and affordable electrocatalysts.This work constructs the interfacial structure of cobalt-iron alloys@phosphates(denoted as CoFe/CoFePO)as OER catalyst through a two-step approach using water-bath and hydrothermal methods,which demonstrated significant OER activity in alkaline media,requiring a low overpotential of 271 mV to achieve 10 mA cm^(−2) and exhibiting a competitive Tafel slope of 65 mV dec^(-1),alongside sustained operational stability.The enhanced performance can be attributed to the improved electrical conductivity due to the participation of CoFe alloys and the increased number of active sites through partial phosphorylation,which synergistically enhances charge transfer processes and accelerates OER kinetics.Moreover,dynamic structural evolution during OER process was thoroughly probed,and the results show that alloys@phosphates gradually evolve into phosphate radicalmodified CoFe hydroxyoxides that act as the actual active phase.Highlighting its practical applicability,the integration of prepared catalyst into zinc-air batteries leads to markedly improved performance,thereby offering promising new strategic directions for the development of next-generation OER electrocatalysts.
基金supported by the National Natural Science Foundation of China(Grant No.52405414)the China Postdoctoral Science Foundation(Grant No.2024M762580)+1 种基金Young Talent Fund of Xi'an Association for Science and Technology(Grant No.0959202513033)the Youth Innovation Team of Shaanxi Universities,and the Fundamental Research Funds for Central Universities.The authors gratefully acknowledge the support by the Instrumental Analysis Center of Xi’an Jiaotong University for sample characterization.
文摘In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalability through modular design.However,traditional manufacturing processes are limited by mold dependence,organic solvent toxicity,and insufficient molding capability for complex structures,resulting in difficulty achieving precise regulation of cross-scale pores.Additive manufacturing(AM)technology employs a digital layered molding strategy to achieve the cross-scale structural regulation of catalysts from macroscopic flow channels to mesopores and micropores.This paper summarizes recent advances in the structural design of monolithic catalysts enabled by AM technologies and highlights their emerging applications in catalytic processes.Structurally,AM-fabricated monoliths have been effectively employed in key chemical reactions such as fuel reforming,CO_(2)conversion,biofuel synthesis.Strategies such as geometrical topology optimization,multi-scale pore synergy,biomimetic structural design,and functional gradient integration have been utilized to enhance heat and mass transport,reduce pressure drops,and improve overall catalytic performance.By overcoming the limitations of traditional catalysts,AM technologies create a new paradigm for addressing the longstanding challenge of coupling mass transfer with reaction kinetics.This approach provides a feasible pathway for driving both theoretical innovation and practical implementation of high-efficiency catalytic systems.
基金supported by the Research Fund of the State Key Laboratory of Solidification Processing(NPU)China(No.2022-QZ-03)+2 种基金the Open Research Fund of National Key Laboratory of Special Vehicle Design,Manufacturing Integration Technology(No.GZ2022KF001).Shenzhen Science and Technology Program(No.JCYJ20210324142805014)Shaanxi Province Youth Science,Technology New Star(No.2022KJXX-20)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2022-4-05).
文摘One-dimensional nanomaterials with hollow structures could provide large space for ion storage and charge accumulation.Herein,TiO_(2)/MoSe_(2)-Carbon nanotube composite(NT)materials were designed and fabricated by the template method and the chelation coordination reaction.The stability and conductivity were improved by the presence of titanium and hollow tubular-architecture carbon in the whole structure.As a result,the as-prepared TiO_(2)/MoSe_(2)-Carbon hybrid achieved a high-rate performance of 760.0 mAh·g^(−1) at a current density of 0.1 A·g^(−1),while still obtaining stability after 300 charge/discharge cycles.The enhancement of the lithium storage capacity mainly contributed to the acceleration of the electron conductivity and the storage kinetics.Moreover,the hollow structure reduced the volume strain and stress caused by the rapid insertion and removal of lithium ions,which ensured the favorable stability of lithium storage.The experiment shows that the kinetic of the TiO_(2)/MoSe_(2)-carbon hybrid during the lithium storage process is dominated by the pseudocapacitance mechanism.This work provides a new idea and scheme for the design and preparation of hierarchical nanotube composite electrode materials.
基金financially supported by the Fundamental Research Funds for the Central Universities,North Minzu University(No.2020KYQD18)the Key Research and Development Program(Talents Introduction Project)of Ningxia(No.2021BEB04027)+1 种基金the Fundamental Research Funds for the Central Universities,North Minzu University(No.2021KJCX04)the Natural Science Foundation of Ningxia Province(No.2022AAC05033)
文摘With the rapid development of flexible equipment,high-energy/-power requirements have been proposed for energy storage devices.Nevertheless,the poor conductivities of metallic oxides and their low levels of transmission of electrons/ions hinder their widespread application.Here,a sandwich-structured Co_(3)O_(4)-Fe_(3)O_(4)(CFO) composite with binder-free was synthesized on a carbon cloth substrate via co-precipitation and partial ion exchange.The appropriate substitution of Co_(3)O_(4)with Fe_(3)O_(4)is favorable in promoting the rapid transfer of electrolyte ions and alleviating changes in volume during the electrochemical studies.When the duration of the substitution reaction is 20 min,the obtained electrode delivers a maximum specific capacitance of 1196.2 Fg^(-1)at a current density of 1 A g^(-1)and a superior capacity retention of~71%when the current density varies from 1to 30 Ag^(-1).Furthermore,the fabricated CFO//activated carbon flexible all-solid-state supercapacitor exhibits arespective maximum energy and power density of 68.7Wh kg^(-1)and 16,000 W kg^(-1)and excellent flexibility.It also displays a specific capacity retention of 81.3%under four continuous bending states at a current density of 6A g^(-1)over 10,000 cycles.These remarkable electrochemical char ac teristics suggest that the sandwich-structured CFO composite displays considerable potential for application in flexible high-energy/-power supercapacitors.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2022MB034)the Development Program Project of the Young Innovation Team of Institutions of Higher Learning in Shandong Province。
文摘Endowing stimuli-responsive materials with micro-nano structures is an intriguing strategy for the fabrication of superwetting surfaces;however,its application is limited by poor chemical/mechanical stability.Herein,a simple and versatile strategy was developed to fabricate durable polymeric superwetting surfaces with photoswitchable wettability on hierarchically structured metallic substrates.Inspired by nature,a novel functional terpolymer incorporating mussel-inspired catechol groups,photoresponsive azobenzene groups,and low-surface-energy fluorine-containing groups was synthesized via solution radical polymerization.The azobenzene-containing terpolymer possesses outstanding photoresponsiveness in both the solution and film states because of the trans-cis isomerization of the azobenzene moieties.After dip-coating with the mussel-inspired azo-copolymer,the as-prepared smart surfaces exhibited a photo-triggered change in wettability between high hydrophobicity and superhydrophilicity.More importantly,these superwetting surfaces with enhanced adhesion properties can tolerate harsh environmental conditions and repeated abrasion tests,thereby demonstrating excellent chemical robustness and mechanical durability.This study paves a new avenue for the convenient and large-scale fabrication of robust smart surfaces that could find widespread potential applications in microfluidic devices,water treatment,and functional coatings.
基金financially supported by the National Natural Science Foundation of China(Nos.52001136,52171179 and 82371913)the Youth Innovation Team of Higher Education Institutions in Shandong Province(No.2023KJ105)Collaborative Innovation Center of Yellow River Basin Pharmaceutical Green Manufacturing and Engineering Equipment,University of Jinan,Jinan 250022,China,Jinan City University Integration Development Strategy Project(No.JNSX2023021).
文摘The novel generation of clean energy has captured substantial public interest as the ecological environment deteriorates and fossil energy sources become depleted,with electrochemical catalysis deemed essential to the progress of clean energy technologies.Core-shell nanocomposite materials exhibit excellent chemical erosion resistance and effectively mitigate issues such as nanoparticle aggregation and sintering.Therefore,core-shell electrocatalysts demonstrate considerable advantages,such as enhanced activity and stability,making them widely applicable in electrocatalysis.This review offers an extensive summary of the latest advances,techniques,and applications of core-shell noble metal-based catalysts in electrocatalysis,encompassing a diverse range of synthesis techniques and strategies designed to fine-tune electrocatalytic performance.The article presents techniques such as seed-mediated growth,electrodeposition,template synthesis,and self-assembly and further delves into control strategies for enhancing electrocatalytic performance via case studies,examining electronic and geometric effects,with the former broken down into strain and ligand effects.Next,the article focuses on the remarkable progress achieved by noble metal-based core-shell structures in enhancing the efficiency of key electrocatalytic reactions,such as the hydrogen evolution reaction(HER),oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and carbon dioxide reduction reaction(CO_(2)RR).Finally,the primary challenges and future prospects in this field are discussed,offering insight that will inform further research and development efforts.The primary objective of this review is to illuminate the design and construction of novel core-shell noble metal-based catalysts for energy storage and conversion technologies.
基金Supported by the Special Fund for Basic Scientific Research of Central-Level Public Welfare Scientific Research Institutes(2024-9007)。
文摘The accuracy of center height detection for corrugated beam guardrails is significantly affected by robot posture in the mobile highway guardrail detection systems based on structured light vision.To address the problem,this paper proposes an integrated calibration method for structured light vision sensors.In the proposed system,the sensor is mounted on a crawler-type mobile robot,which scans and measures the center height of guardrails while in motion.However,due to external disturbances such as uneven road surfaces and vehicle vibrations,the posture of the robot may deviate,causing displacement of the sensor platform and resulting in spatial 3D measurement errors.To overcome this issue,the system integrates inertial measurement unit(IMU)data into the sensor calibration process,enabling realtime correction of posture deviations through sensor fusion.This approach achieves a unified calibration of the structured light vision system,effectively compensates for posture-induced errors,and enhances detection accuracy.A prototype was developed and tested in both laboratory and real highway environments.Experimental results demonstrate that the proposed method enables accurate center height detection of guardrails under complex road conditions,significantly reduces posture-related measurement errors,and greatly improves the efficiency and reliability of traditional detection methods.
基金supported by the National Natural Science Foundation of China[Grant Nos.62205367 and 62141506]the Suzhou Basic Research Pilot Project[Grant Nos.SSD2023006 and SJC2021013]the National Key Research and Development Program of China[Grant No.2023YFF1205700].
文摘Maintaining the s-polarization state of laser beams is important to achieve high modulation depth in a laser-interference-based super-resolution structured illumination microscope(SR-SIM).However,the imperfect optical components can depolarize the laser beams hence degenerating the modulation depth.Here,we first presented a direct measurement method designed to estimate the modulation depth more precisely by shifting illumination patterns with equal phase steps.This measurement method greatly reduces the dependence of modulation depths on the samples,and then developed a polarization optimization method to achieve high modulation depth at all orientations by actively and quantitatively compensating for the additional phase difference using a combination of waveplate and a liquid crystal variable retarder(LCVR).Experimental results demonstrate that our method can achieve illumination patterns with modulation depth higher than 0.94 at three orientations with only one LCVR voltage,which enables isotropic resolution improvement.
文摘Materials engineering plays a key role in the field of electrochemical energy storage,and considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using novel functional electrode materials.Materials with hollow structures are of particular interests due to their low density,large specific surface area and high porosity,making them promising candidates for energy conversion and storage.The Kirkendall effect has been widely applied for the synthesis of nanoscale hollow structures,which involves an unbalanced counter diffusion through a reaction interface.Herein,the recent progress on the use of the nanoscale Kirkendall effect to synthesize hollow nanostructures,including nanoparticles,one-dimensional(1-D),two-dimensional(2-D),and three-dimensional(3-D)nanostructures,and their potential applications in energy storage devices are summarized and discussed.And prospects is made for the future development of this research field.
基金supports from National Natural Science Foundation of China(Grant No.12174097).
文摘Quantum entanglement, a fundamental concept in quantum mechanics, lies at the heart of many current and futurequantum technologies. A pivotal task is the generation and control of diverse quantum entangled states in a more compactand flexible manner. Here, we introduce an approach to achieve diverse path entanglement by exploiting the interactionbetween noncommutative metasurfaces and entangled photons. Different from other path entanglements, ourquantum path entanglement is evolution path entanglement of photons on Poincaré sphere. Due to quantum entanglementbetween idler photons and structured signal photons, evolution path of idler photons on the fundamental Poincarésphere can be nonlocally mirrored by structured signal photons on any higher-order Poincaré sphere, resulting in quantumpath entanglement. Benefiting from noncommutative metasurfaces, diverse quantum path entanglement can beswitched across different higher-order Poincaré spheres using distinct combination sequences of metasurfaces. Ourmethod allows for the tuning of diverse quantum path entanglement across a broad spectrum of quantum states, offeringa significant advancement in the manipulation of quantum entanglement.
基金supported by the National Natu-ral Science Foundation of China(Nos.52107232 and 52377026)China Postdoctoral Science Foundation(No.2021M702563)+2 种基金State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE22312)Taishan Scholars and Young Experts Program of Shan-dong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)and Fundamental Research Funds for the Central Universities(No.xzy012024004).
文摘Polymer dielectrics are required to maintain high energy density at elevated temperatures for advanced power and electronic systems.Herein,we report a novel solution-processed core-shell structured poly-imide(PI)nanocomposite with moderate dielectric constant HfO_(2)core and wide-bandgap Al_(2)O_(3)shell,ef-fectively addressing the typical trade-off between dielectric constant and breakdown strength in dielectric nanocomposites predominant at elevated temperatures.The formation of improved dielectrically match-ing interfaces by the rationally designed dielectric constant gradient from core-shell-matrix remarkably mitigates the distortion of the electric field around the interfaces,resulting in a high breakdown strength.Wide band gap Al_(2)O_(3)shell also introduces deeper traps to impede the conduction loss.The validity of Al_(2)O_(3)shell has been proved via experiments and simulations.Accordingly,HfO_(2)@Al_(2)O_(3)/PI nanocompos-ite exhibits an excellent charge-discharge efficiency of 91.7%at 300 MV/m and a maximum discharged energy density of 2.94 J/cm^(3)at 150℃,demonstrating its potential for high-temperature energy storage.
基金supported by the National Nature Science Foundation of China(No.22269021)Tianshan Talent Project of Xinjiang Uygur Autonomous Region(No.2023TSYCQNTJ0039)the Open project of Key Laboratory in Xinjiang Uygur Autonomous Region of China(No.2023D04027).
文摘Hydrogen production coupled with small molecule oxidation derived by renewable energy power has been widely studied as an effective method to reduce energy consumption and prepare added value production.Here,the copper-cobalt phosphide with a multilevel structure has been designed based on the hard and soft acids and bases theory.The nanocone composed of lamellas presented a sharp tip,which a positive effect on the mass transfer enhanced by a local electric field,and the nanolamellas contain CoP/Cu_(3)P interface provide the highly selective active site for the gluconic acid(GNA)synthesis and hydrogen evolution.The catalyst can drive hydrogen evolution at 5 A·cm^(-2)up to 437 h without active decay,and the electrocatalytic glucose oxidation at anode presents high efficiency due to Cu(I)introduction and the synergetic effect between interfaces.Density functional theory(DFT)calculation shows that water splitting more readily occurs at the CoP,which provides adsorbed H and-OH for hydrogen evolution and glucose oxidation,respectively,and glucose adsorption more readily occurs at the Cu_(3)P,which presents lower conversion energy for high value-added GNA.Efficient hydrogen evolution and glucose conversion indicate its high intrinsic activity and synergetic effect.This work provides a special interface construction strategy for the catalytic conversion of hydrogen and small molecules.
