The rapid growth in available network bandwidth has directly contributed to an exponential increase in mobile data traffic,creating significant challenges for network energy consumption.Also,with the extraordinary gro...The rapid growth in available network bandwidth has directly contributed to an exponential increase in mobile data traffic,creating significant challenges for network energy consumption.Also,with the extraordinary growth of mobile communications,the data traffic has dramatically expanded,which has led to massive grid power consumption and incurred high operating expenditure(OPEX).However,the majority of current network designs struggle to efficientlymanage a massive amount of data using little power,which degrades energy efficiency performance.Thereby,it is necessary to have an efficient mechanism to reduce power consumption when processing large amounts of data in network data centers.Utilizing renewable energy sources to power the Cloud Radio Access Network(C-RAN)greatly reduces the need to purchase energy from the utility grid.In this paper,we propose a bandwidth-aware hybrid energypowered C-RAN that focuses on throughput and energy efficiency(EE)by lowering grid usage,aiming to enhance the EE.This paper examines the energy efficiency,spectral efficiency(SE),and average on-grid energy consumption,dealing with the major challenges of the temporal and spatial nature of traffic and renewable energy generation across various network setups.To assess the effectiveness of the suggested network by changing the transmission bandwidth,a comprehensive simulation has been conducted.The numerical findings support the efficacy of the suggested approach.展开更多
Octopuses,due to their flexible arms,marvelous adaptability,and powerful suckers,are able to effortlessly grasp and disengage various objects in the marine surrounding without causing devastation.However,manipulating ...Octopuses,due to their flexible arms,marvelous adaptability,and powerful suckers,are able to effortlessly grasp and disengage various objects in the marine surrounding without causing devastation.However,manipulating delicate objects such as soft and fragile foods underwater require gentle contact and stable adhesion,which poses a serious challenge to now available soft grippers.Inspired by the sucker infundibulum structure and flexible tentacles of octopus,herein we developed a hydraulically actuated hydrogel soft gripper with adaptive maneuverability by coupling multiple hydrogen bond-mediated supramolecular hydrogels and vat polymerization three-dimensional printing,in which hydrogel bionic sucker is composed of a tunable curvature membrane,a negative pressure cavity,and a pneumatic chamber.The design of the sucker structure with the alterable curvature membrane is conducive to realize the reliable and gentle switchable adhesion of the hydrogel soft gripper.As a proof-of-concept,the adaptive hydrogel soft gripper is capable of implement diversified underwater tasks,including gingerly grasping fragile foods like egg yolks and tofu,as well as underwater robots and vehicles that station-keeping and crawling based on switchable adhesion.This study therefore provides a transformative strategy for the design of novel soft grippers that will render promising utilities for underwater exploration soft robotics.展开更多
Through studying several kinds of chaotic mappings' distributions of orbital points, we analyze the capabilityof the chaotic mutations based on these mappings. Nunerical experiments support our conclusions very we...Through studying several kinds of chaotic mappings' distributions of orbital points, we analyze the capabilityof the chaotic mutations based on these mappings. Nunerical experiments support our conclusions very well. Thecapability analysis also led to a self-adaptive mechanism of chaotic mutation. The introducing of the self-adaptivechaotic mutation can improve the performance of genetic algorithm very prominently.展开更多
Credit risk is the core issue of supply chain finance. In the supply chain, problems happened in different enterprises can influent the whole to different degrees through transferring, thus statuses of all enterprises...Credit risk is the core issue of supply chain finance. In the supply chain, problems happened in different enterprises can influent the whole to different degrees through transferring, thus statuses of all enterprises and their different influences should be considered when evaluating the supply chain’s credit risk. We examine the characters of supply chain network and complex network, use the local growing complex network to simulate the real supply chain, use cluster analysis to classify the company into several levels;Introducing each level’s self-adaption weight formula according to the company’s quantity and degrees of this level and use the weight to improve the credit evaluation method. The research results indicate that complex network can be used to simulate the supply chain. The credit risk evaluation (CRE) of an enterprise level with bigger note degrees has a greater weight in the supply chain system’s CRE, thus has greater effect on the whole chain. Considering different influences of different enterprise levels can improve credit risk evaluation method’s sensitivity.展开更多
Low-order Duffing and high-order Rossler chaotic oscillator are connected together and new self-adaption frequency detection method is presented. The frequency difference control between unknown signal and the periodi...Low-order Duffing and high-order Rossler chaotic oscillator are connected together and new self-adaption frequency detection method is presented. The frequency difference control between unknown signal and the periodic driving force is realized in this paper and the self-adaption is obtained. Thus, the detection precision and speed are promoted. The limitation that there are too many chaotic oscillators in Duffing system is broken. Meanwhile the disadvantage that the detection speed is lower in R ssler chaotic control is overcome. The self-adaption choice of frequency difference control is realized using the Duffing and Rssler different chaotic oscillators to obtain unknown signal frequency. The simulation results show that the presented method is feasible and effective.展开更多
Solid lubricating coatings play a crucial role in preventing friction and wear failure of the hot-end sliding components in aviation engines.In this study,VAlN/Ag multi-layer coatings with excellent interfacial matchi...Solid lubricating coatings play a crucial role in preventing friction and wear failure of the hot-end sliding components in aviation engines.In this study,VAlN/Ag multi-layer coatings with excellent interfacial matching were fabricated using a hybrid magnetron sputtering technique.The type and energy of discharge plasmas were analyzed to comprehend their effects on depositing coatings.The coatings exhibit self-adaptive lubrication properties during the designed consecutive friction with stepwise heating from 25℃to 650℃.The microstructure evolution during early friction facilitates sufficient tribo-chemical reaction at 650℃,leading to the formation of a distinctive"ball-on-rail"structure that significantly reduces friction coefficient.Based on the first-principles calculations,it was found that the bond energy of Ag-O is lower than that of V-O in both AgVO_(3)and Ag_(3)VO_(4),which promotes slipping along the(110)crystal plane and contributes to exceptional tribological properties.The fatigue wear failure mechanism of hard coatings under the thermal-force coupling effects has been elucidated,alongside an exploration of consecutive tribology mechanism at atomic scales over a wide temperature range.展开更多
Global warming and energy crisis are two major challenges in the new-century.Wearable materials that enable all-seasonal self-adapting thermal comfort without additional energy-input attract significant attention as a...Global warming and energy crisis are two major challenges in the new-century.Wearable materials that enable all-seasonal self-adapting thermal comfort without additional energy-input attract significant attention as a solution to the increasing severity of extreme climate-change.Inspired by autologous temperature-regulation and multidimensional-sensing origins of nature-skin composed of nature collagen fibers,this study engineered a nanoscale wearable natural fibers-derived thermochromic material(TMEH-skin)for robust all-season self-adapting thermal management by tactically integrating traditional immersion and spraying methods with layer-by-layer stacking-strategy.Because of the on-demand multi-functional layer-structure design,TMEH-skin achieves spontaneous~38.16%visible lightmodulation and~95.1%infrared-emission,demonstrating outstanding double-self-switching thermal management origins by simple color-changing without additional energy-input.Moreover,TMEH-skin has gratifying tensile strength of 13.18 MPa,water vapor permeability,electrical-conductivity,and hydrophobicity,further broadening the application potential and scenarios as wearable materials.In applications for military-missions or reconnaissance behind enemy-lines,TMEH-skin robustly integrates the multi-functionalities of wearing-comfort,physiological signal-response capability for accurate transmission of Morse-code,and thermal management performances under special circumstances,indicating its tremendous potential for smart military-applications.Simulation results show that TMEH-skin has prominent energy-saving efficiency in cities with different climate zones.This study provides a new reference to the booming innovation of natural-derived wearable materials for all-seasonal self-adapting thermal management.展开更多
Gecko-inspired van der Waals force-based adhesion technology demonstrates significant potential for robotic operations.While superior adhesion is achieved under parallel contact during testing,engineering operations o...Gecko-inspired van der Waals force-based adhesion technology demonstrates significant potential for robotic operations.While superior adhesion is achieved under parallel contact during testing,engineering operations often involve non-parallel contact,weakening adhesion,and compromising task stability and efficiency.Stable attachment under such non-parallel contacts remains challenging.Inspired by the soft muscle and rigid bone in the gecko’s sole,this study proposes a self-adaptive core-shell dry adhesive by embedding a thin,rigid piece into a soft,thick elastomer comprising a top adhesion tip with a mushroom-like geometry for interfacial adhesion based on the van der Waals force and a bottom core-shell configuration for interface stress regulation.Unlike traditional core-shell structures with a fixed“dead core,”the proposed“live core”rotates within the soft shell,mimicking skeletal joints.This enables stress equalization at the interface and facilitates adaptive contact to macroscopic interfacial angle errors.This innovative core-shell configuration demonstrates an adhesion strength 100 times higher than conventional homogeneous structures under non-parallel contact and offers anti-overturning ability by mitigating torsional effects.The proposed strategy can advance the development of gecko-inspired adhesion-based devices and systems.展开更多
Time Division Multiplexing-Passive Optical Networks(TDM-PONs)play a vital role in Fiberto-the-Home(FTTH)deployments.To improve the service quality of home networks,FTTH is expanding to the Fiber-to-the-Room(FTTR)scena...Time Division Multiplexing-Passive Optical Networks(TDM-PONs)play a vital role in Fiberto-the-Home(FTTH)deployments.To improve the service quality of home networks,FTTH is expanding to the Fiber-to-the-Room(FTTR)scenario,where fibers are deployed to connect individual rooms(i.e.,Fiber In-premises Network(FIN)in the ITU-T G.9940 standard).In this scenario,a point-to-multipoint(P2MP)fiber network is deployed as FTTR FIN to offer gigabit access to each room,which forms a two-tier cascaded network together with the FTTH segment.To optimize the capacity utilization of the cascaded network and reduce the overall system cost,a centralized architecture,known as Centralized Fixed Access Network(C-FAN),has been introduced.C-FAN centralizes the medium access control(MAC)modules of both the FTTH and FTTR networks at the FTTH’s Optical Line Terminal(OLT)for unified control and management of the cascaded network.We develop a unified bandwidth scheduling protocol by extending the ITU-T PON standard for both the upstream and downstream directions of C-FAN.We also propose a unified dynamic bandwidth allocation(UDBA)algorithm for efficient bandwidth allocation for multiple traffic flows in the two-tier cascaded network.Simulations are conducted to evaluate the performance of the proposed control protocol and the UDBA algorithm.The results show that,in comparison to the conventional DBA algorithm,the UDBA algorithm can utilize upstream bandwidth more efficiently to reduce packet delay and loss,without adversely impacting downstream transmission performance.展开更多
The intrinsic volume changes(about 300%)of Si anode during the lithiation/delithiation leads to the serious degradation of battery performance despite of theoretical capacity of 3579 mAh g^(-1) of Si.Herein,a three-di...The intrinsic volume changes(about 300%)of Si anode during the lithiation/delithiation leads to the serious degradation of battery performance despite of theoretical capacity of 3579 mAh g^(-1) of Si.Herein,a three-dimensional(3D)conductive polymer binder with adjustable crosslinking density has been designed by employing citric acid(CA)as a crosslinker between the carboxymethyl cellulose(CMC)and the poly(3,4-ethylenedioxythiophene)poly-(styrene-4-sulfonate)(PEDOT:PSS)to stabilize Si anode.By adjusting the crosslinking density,the binder can achieve a balance between rigidity and flexibility to adapt the volume expansion upon lithiation and reversible volume recovery after delithiation of Si.Therefore,Si/CMC-CA-PEDOT:PSS(Si/CCP)electrode demonstrates an excellent performance with high capacities of 2792.3 mAh g^(-1) at 0.5 A g^(-1) and a high area capacity above 2.6 mAh cm^(-2) under Si loading of 1.38 mg cm^(-2).The full cell Si/CCP paired with Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2) cathode discharges a capacity of 199.0 mAh g^(-1) with 84.3%ICE at 0.1 C and the capacity retention of 95.6%after 100 cycles.This work validates the effectiveness of 3D polymer binder and provides new insights to boost the performance of Si anode.展开更多
Terahertz(THz)switches are essential components of THz communication systems.THz switches based on conventional waveguides and photonic crystal structures are sensitive to manufacturing defects and sharp bending,resul...Terahertz(THz)switches are essential components of THz communication systems.THz switches based on conventional waveguides and photonic crystal structures are sensitive to manufacturing defects and sharp bending,resulting in high scattering losses.In addition,THz switches with tunable working bandwidths have not yet been demonstrated.Here,we design THz switches based on a topological valley photonic crystal(VPC)structure using magnetic materials,which can achieve high forward transmittance based on the unique spin–valley locking effect.The broad working bandwidth allows selective turning on and off at a designed wavelength region by controlling the applied magnetic field.The designed THz switch can achieve an extinction ratio of up to 31.66 dB with an insertion loss of less than 0.13 dB.The 3-dB bandwidth is up to 49 GHz.This tunable THz switch can be experimentally fabricated by current fabrication techniques and thus can find broad applications in THz communication systems.展开更多
Maximize the resource utilization efficiency and guarantee the quality of service(QoS)of users by selecting the network are the key issues for heterogeneous network operators,but the resources occupied by users in dif...Maximize the resource utilization efficiency and guarantee the quality of service(QoS)of users by selecting the network are the key issues for heterogeneous network operators,but the resources occupied by users in different networks cannot be compared directly.This paper proposes a network selection algorithm for heterogeneous network.Firstly,the concept of equivalent bandwidth is proposed,through which the actual resources occupied by users with certain QoS requirements in different networks can be compared directly.Then the concept of network applicability is defined to express the abilities of networks to support different services.The proposed network selection algorithm first evaluates whether the network has enough equivalent bandwidth required by the user and then prioritizes network with poor applicability to avoid the situation that there are still residual resources in entire network,but advanced services can not be admitted.The simulation results show that the proposed algorithm obtained better performance than the baselines in terms of reducing call blocking probability and improving network resource utilization efficiency.展开更多
In recent years,two-dimensional layered transition metal dichalcogenides-based multicomponent com-posites(MCCs)acting as electromagnetic wave(EMW)materials have received intensive investiga-tions.However,the vulcanica...In recent years,two-dimensional layered transition metal dichalcogenides-based multicomponent com-posites(MCCs)acting as electromagnetic wave(EMW)materials have received intensive investiga-tions.However,the vulcanication of metal greatly hindered their enhancement of EMW absorption per-formances(EMWAPs).Herein,a combined metal-organic frameworks-derived and hydrothermal strat-egy was presented to produce yolk-shell structure(YSS)CoNi@Air@C@MoS_(2) MCCs.The results showed that the thermal and hydrothermal treatments resulted in the generation of YSS and two-dimensional MoS_(2) nanosheets,which maintained the original morphology of CoNi Prussian blue analogues.The pro-tection of thick C layer well inhibited the vulcanization of inner CoNi alloy.The formed sheet-like MoS_(2) further optimized impedance matching characteristics,which led to the satisfactory EMWAPs of CoNi@Air@C@MoS_(2) MCCs.Furthermore,the EMWAPs could be further improved by optimizing the Ni:Co atom ratios CoNi@Air@C@MoS_(2) MCCs,which stemmed from their boosted impedance matching perfor-mances,EMW attention and polarization loss abilities.The absorption bandwidth and reflection loss val-ues for YSS CoNi@Air@C@MoS_(2) MCCs are 8 GHz and−60.83 dB,which covered almost all C-Ku bands.In general,our research work provided a valid strategy to produce YSS magnetic CoNi@Air@C@MoS_(2) MCCs with high efficiency,which well avoided the vulcanization of metal nanoparticles,made best of hollow engineering and atomic ratio optimization strategy to boost the comprehensive EMWAPs.展开更多
Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion.However,the photo-corrosion and unsuitable energy band positions still hinder their pract...Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion.However,the photo-corrosion and unsuitable energy band positions still hinder their practical application for hydrogen production from water in photoelectrochemical systems.Here,an in-situ photo-oxidation method is proposed for achieving self-adapting activation of BiVO_(4)-based photoanodes with surface-encapsulated CuGaS_(2)particles by the ZnO layer.The self-adapting activation demotes the energy band positions of CuGaS_(2),establishing an S-scheme structure with BiVO_(4),resulting in an efficient p-n junction photoanode.The optimal sample exhibits enhanced photocurrent and an onset potential cathodically shifted by~300 mV compared with BiVO_(4),which is attributed to significantly enhanced charge transport and transfer efficiencies.As expected,it attains the highest photocurrent value of 5.87 mA·cm^(-2),aided by a hole scavenger at 1.23 V versus a reversible hydrogen electrode,which significantly surpasses that of BiVO_(4)(4.32 mA·cm^(-2)).展开更多
Ultra-narrow bandwidth mode-locked lasers with tunable pulse duration can be versatile light sources for diverse applications.However,the spectral-temporal control of a narrow bandwidth mode-locked laser is challengin...Ultra-narrow bandwidth mode-locked lasers with tunable pulse duration can be versatile light sources for diverse applications.However,the spectral-temporal control of a narrow bandwidth mode-locked laser is challenging due to limited gain and nonlinearity,hindering practical applications of such lasers.We demonstrate a pulse duration widely tunable mode-locked ultra-narrow bandwidth laser using a composite filtering mechanism and a single-wall carbon nanotube.The laser pulse duration can be adjusted from 481 ps to 1.38 ns,which is the widest tuning range achieved in narrow-bandwidth passively mode-locked lasers.When the pulse duration is 1.38 ns,the corresponding spectral width reaches 4 pm(502 MHz).Numerical simulations support the experimental results and show that the evolution of long pulses in the laser cavity behaves similarly to a quasi-continuous wave with a low breathing ratio.We have not only designed a simple and flexible tunable scheme for the dilemma of spectral-temporal control in narrow-bandwidth mode-locked fiber lasers but also provided a unique and idealized light source for various applications that takes into account robust output.展开更多
Following publication of the original article[1],the authors found that they pasted the same data when drawing XRD for sample NCO-1 and NCO-2 in Fig.2a,however,the XRD of all four samples in the manuscript was tested,...Following publication of the original article[1],the authors found that they pasted the same data when drawing XRD for sample NCO-1 and NCO-2 in Fig.2a,however,the XRD of all four samples in the manuscript was tested,and XRD raw data were kept and can be offered.The correct Fig.2 has been provided in this Correction.展开更多
With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to...With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to ensure closed-loop stability when employing a time-varying bandwidth,as well as the supporting mathematical foundations,remain insufficiently studied.This paper investigates the stability condition for active disturbance rejection control(ADRC)with a time-varying bandwidth extended state observer(ESO).A new stability condition is derived,which means that the upper bound of rate of change for ESO bandwidth should be restricted.Moreover,under the proposed condition,the closed-loop stability of ADRC with a time-varying bandwidth observer is rigorously proved for nonlinear uncertainties.In simulations,the necessity of the proposed condition is illustrated,demonstrating that the rate of change of ESO bandwidth is crucial for closed-loop stability.展开更多
The explosive growth of data traffic and heterogeneous service requirements of 5G networks—covering Enhanced Mobile Broadband(eMBB),Ultra-Reliable Low Latency Communication(URLLC),and Massive Machine Type Communicati...The explosive growth of data traffic and heterogeneous service requirements of 5G networks—covering Enhanced Mobile Broadband(eMBB),Ultra-Reliable Low Latency Communication(URLLC),and Massive Machine Type Communication(mMTC)—present tremendous challenges to conventional methods of bandwidth allocation.A new deep reinforcement learning-based(DRL-based)bandwidth allocation system for real-time,dynamic management of 5G radio access networks is proposed in this paper.Unlike rule-based and static strategies,the proposed system dynamically updates itself according to shifting network conditions such as traffic load and channel conditions to maximize the achievable throughput,fairness,and compliance with QoS requirements.By using extensive simulations mimicking real-world 5G scenarios,the proposed DRL model outperforms current baselines like Long Short-Term Memory(LSTM),linear regression,round-robin,and greedy algorithms.It attains 90%–95%of the maximum theoretical achievable throughput and nearly twice the conventional equal allocation.It is also shown to react well under delay and reliability constraints,outperforming round-robin(hindered by excessive delay and packet loss)and proving to be more efficient than greedy approaches.In conclusion,the efficiency of DRL in optimizing the allocation of bandwidth is highlighted,and its potential to realize self-optimizing,Artificial Intelligence-assisted(AI-assisted)resource management in 5G as well as upcoming 6G networks is revealed.展开更多
文摘The rapid growth in available network bandwidth has directly contributed to an exponential increase in mobile data traffic,creating significant challenges for network energy consumption.Also,with the extraordinary growth of mobile communications,the data traffic has dramatically expanded,which has led to massive grid power consumption and incurred high operating expenditure(OPEX).However,the majority of current network designs struggle to efficientlymanage a massive amount of data using little power,which degrades energy efficiency performance.Thereby,it is necessary to have an efficient mechanism to reduce power consumption when processing large amounts of data in network data centers.Utilizing renewable energy sources to power the Cloud Radio Access Network(C-RAN)greatly reduces the need to purchase energy from the utility grid.In this paper,we propose a bandwidth-aware hybrid energypowered C-RAN that focuses on throughput and energy efficiency(EE)by lowering grid usage,aiming to enhance the EE.This paper examines the energy efficiency,spectral efficiency(SE),and average on-grid energy consumption,dealing with the major challenges of the temporal and spatial nature of traffic and renewable energy generation across various network setups.To assess the effectiveness of the suggested network by changing the transmission bandwidth,a comprehensive simulation has been conducted.The numerical findings support the efficacy of the suggested approach.
基金the financial support from the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB0470303)the National Key Research and Development Program of China (2022YFB4600101)+5 种基金the National Natural Science Foundation of China (52175201)the Research Program of Science and Technology Department of Gansu Province (24JRRA059, 24JRRA044, and 24YFFA014)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai (AMGM2024F12)the Major Program (ZYFZFX-2) of the Lanzhou Institute of Chemical Physics, CASthe Special Research Assistant Project of the Chinese Academy of Sciencesthe Oasis Scholar of Shihezi University
文摘Octopuses,due to their flexible arms,marvelous adaptability,and powerful suckers,are able to effortlessly grasp and disengage various objects in the marine surrounding without causing devastation.However,manipulating delicate objects such as soft and fragile foods underwater require gentle contact and stable adhesion,which poses a serious challenge to now available soft grippers.Inspired by the sucker infundibulum structure and flexible tentacles of octopus,herein we developed a hydraulically actuated hydrogel soft gripper with adaptive maneuverability by coupling multiple hydrogen bond-mediated supramolecular hydrogels and vat polymerization three-dimensional printing,in which hydrogel bionic sucker is composed of a tunable curvature membrane,a negative pressure cavity,and a pneumatic chamber.The design of the sucker structure with the alterable curvature membrane is conducive to realize the reliable and gentle switchable adhesion of the hydrogel soft gripper.As a proof-of-concept,the adaptive hydrogel soft gripper is capable of implement diversified underwater tasks,including gingerly grasping fragile foods like egg yolks and tofu,as well as underwater robots and vehicles that station-keeping and crawling based on switchable adhesion.This study therefore provides a transformative strategy for the design of novel soft grippers that will render promising utilities for underwater exploration soft robotics.
基金The project supported by National Natural Science Foundation of China under Grant No. 60074020
文摘Through studying several kinds of chaotic mappings' distributions of orbital points, we analyze the capabilityof the chaotic mutations based on these mappings. Nunerical experiments support our conclusions very well. Thecapability analysis also led to a self-adaptive mechanism of chaotic mutation. The introducing of the self-adaptivechaotic mutation can improve the performance of genetic algorithm very prominently.
文摘Credit risk is the core issue of supply chain finance. In the supply chain, problems happened in different enterprises can influent the whole to different degrees through transferring, thus statuses of all enterprises and their different influences should be considered when evaluating the supply chain’s credit risk. We examine the characters of supply chain network and complex network, use the local growing complex network to simulate the real supply chain, use cluster analysis to classify the company into several levels;Introducing each level’s self-adaption weight formula according to the company’s quantity and degrees of this level and use the weight to improve the credit evaluation method. The research results indicate that complex network can be used to simulate the supply chain. The credit risk evaluation (CRE) of an enterprise level with bigger note degrees has a greater weight in the supply chain system’s CRE, thus has greater effect on the whole chain. Considering different influences of different enterprise levels can improve credit risk evaluation method’s sensitivity.
基金supported by the Talent Scientific Research Foundation of China Three Gorges University(Grant No.KJ2013B079)
文摘Low-order Duffing and high-order Rossler chaotic oscillator are connected together and new self-adaption frequency detection method is presented. The frequency difference control between unknown signal and the periodic driving force is realized in this paper and the self-adaption is obtained. Thus, the detection precision and speed are promoted. The limitation that there are too many chaotic oscillators in Duffing system is broken. Meanwhile the disadvantage that the detection speed is lower in R ssler chaotic control is overcome. The self-adaption choice of frequency difference control is realized using the Duffing and Rssler different chaotic oscillators to obtain unknown signal frequency. The simulation results show that the presented method is feasible and effective.
基金supported by the National Natural Science Foundation of China(No.52025014)Natural Science Foundation of Zhejiang Province(No.LQ23E010002)+1 种基金Natural Science Foundation of Ningbo(No.2023QL049)Major Special Project of Ningbo(No.2023Z022).
文摘Solid lubricating coatings play a crucial role in preventing friction and wear failure of the hot-end sliding components in aviation engines.In this study,VAlN/Ag multi-layer coatings with excellent interfacial matching were fabricated using a hybrid magnetron sputtering technique.The type and energy of discharge plasmas were analyzed to comprehend their effects on depositing coatings.The coatings exhibit self-adaptive lubrication properties during the designed consecutive friction with stepwise heating from 25℃to 650℃.The microstructure evolution during early friction facilitates sufficient tribo-chemical reaction at 650℃,leading to the formation of a distinctive"ball-on-rail"structure that significantly reduces friction coefficient.Based on the first-principles calculations,it was found that the bond energy of Ag-O is lower than that of V-O in both AgVO_(3)and Ag_(3)VO_(4),which promotes slipping along the(110)crystal plane and contributes to exceptional tribological properties.The fatigue wear failure mechanism of hard coatings under the thermal-force coupling effects has been elucidated,alongside an exploration of consecutive tribology mechanism at atomic scales over a wide temperature range.
基金the Institute of Biomass&Functional Materials of Shaanxi University of Science and Technology for funding this research workfinancially supported by the National Natural Science Foundation of China(2207081675,22278257,22308209)+1 种基金the Key R&D Program of Shaanxi Province(2024SF-YBXM-586)the Project of Innovation Capability Support Program in Shaanxi Province(2024ZC-KJXX-005)。
文摘Global warming and energy crisis are two major challenges in the new-century.Wearable materials that enable all-seasonal self-adapting thermal comfort without additional energy-input attract significant attention as a solution to the increasing severity of extreme climate-change.Inspired by autologous temperature-regulation and multidimensional-sensing origins of nature-skin composed of nature collagen fibers,this study engineered a nanoscale wearable natural fibers-derived thermochromic material(TMEH-skin)for robust all-season self-adapting thermal management by tactically integrating traditional immersion and spraying methods with layer-by-layer stacking-strategy.Because of the on-demand multi-functional layer-structure design,TMEH-skin achieves spontaneous~38.16%visible lightmodulation and~95.1%infrared-emission,demonstrating outstanding double-self-switching thermal management origins by simple color-changing without additional energy-input.Moreover,TMEH-skin has gratifying tensile strength of 13.18 MPa,water vapor permeability,electrical-conductivity,and hydrophobicity,further broadening the application potential and scenarios as wearable materials.In applications for military-missions or reconnaissance behind enemy-lines,TMEH-skin robustly integrates the multi-functionalities of wearing-comfort,physiological signal-response capability for accurate transmission of Morse-code,and thermal management performances under special circumstances,indicating its tremendous potential for smart military-applications.Simulation results show that TMEH-skin has prominent energy-saving efficiency in cities with different climate zones.This study provides a new reference to the booming innovation of natural-derived wearable materials for all-seasonal self-adapting thermal management.
基金supported by the National Natural Science Foundation(52025055,52175546,and 52405624)the Shaanxi University Youth Innovation Team.
文摘Gecko-inspired van der Waals force-based adhesion technology demonstrates significant potential for robotic operations.While superior adhesion is achieved under parallel contact during testing,engineering operations often involve non-parallel contact,weakening adhesion,and compromising task stability and efficiency.Stable attachment under such non-parallel contacts remains challenging.Inspired by the soft muscle and rigid bone in the gecko’s sole,this study proposes a self-adaptive core-shell dry adhesive by embedding a thin,rigid piece into a soft,thick elastomer comprising a top adhesion tip with a mushroom-like geometry for interfacial adhesion based on the van der Waals force and a bottom core-shell configuration for interface stress regulation.Unlike traditional core-shell structures with a fixed“dead core,”the proposed“live core”rotates within the soft shell,mimicking skeletal joints.This enables stress equalization at the interface and facilitates adaptive contact to macroscopic interfacial angle errors.This innovative core-shell configuration demonstrates an adhesion strength 100 times higher than conventional homogeneous structures under non-parallel contact and offers anti-overturning ability by mitigating torsional effects.The proposed strategy can advance the development of gecko-inspired adhesion-based devices and systems.
基金supported by National Nature Science Founding of China(62101372)Open Fund of IPOC(BUPT,IPOC2022A07)+1 种基金State Key Laboratory of Advanced Optical Communication Systems and Networks(2023GZKF11)Leading Youth Talents of Innovation and Entrepreneurship of Gusu(ZXL2023162).
文摘Time Division Multiplexing-Passive Optical Networks(TDM-PONs)play a vital role in Fiberto-the-Home(FTTH)deployments.To improve the service quality of home networks,FTTH is expanding to the Fiber-to-the-Room(FTTR)scenario,where fibers are deployed to connect individual rooms(i.e.,Fiber In-premises Network(FIN)in the ITU-T G.9940 standard).In this scenario,a point-to-multipoint(P2MP)fiber network is deployed as FTTR FIN to offer gigabit access to each room,which forms a two-tier cascaded network together with the FTTH segment.To optimize the capacity utilization of the cascaded network and reduce the overall system cost,a centralized architecture,known as Centralized Fixed Access Network(C-FAN),has been introduced.C-FAN centralizes the medium access control(MAC)modules of both the FTTH and FTTR networks at the FTTH’s Optical Line Terminal(OLT)for unified control and management of the cascaded network.We develop a unified bandwidth scheduling protocol by extending the ITU-T PON standard for both the upstream and downstream directions of C-FAN.We also propose a unified dynamic bandwidth allocation(UDBA)algorithm for efficient bandwidth allocation for multiple traffic flows in the two-tier cascaded network.Simulations are conducted to evaluate the performance of the proposed control protocol and the UDBA algorithm.The results show that,in comparison to the conventional DBA algorithm,the UDBA algorithm can utilize upstream bandwidth more efficiently to reduce packet delay and loss,without adversely impacting downstream transmission performance.
基金Financial support by the NSFC no. 52371224, 51972156, and 51872131
文摘The intrinsic volume changes(about 300%)of Si anode during the lithiation/delithiation leads to the serious degradation of battery performance despite of theoretical capacity of 3579 mAh g^(-1) of Si.Herein,a three-dimensional(3D)conductive polymer binder with adjustable crosslinking density has been designed by employing citric acid(CA)as a crosslinker between the carboxymethyl cellulose(CMC)and the poly(3,4-ethylenedioxythiophene)poly-(styrene-4-sulfonate)(PEDOT:PSS)to stabilize Si anode.By adjusting the crosslinking density,the binder can achieve a balance between rigidity and flexibility to adapt the volume expansion upon lithiation and reversible volume recovery after delithiation of Si.Therefore,Si/CMC-CA-PEDOT:PSS(Si/CCP)electrode demonstrates an excellent performance with high capacities of 2792.3 mAh g^(-1) at 0.5 A g^(-1) and a high area capacity above 2.6 mAh cm^(-2) under Si loading of 1.38 mg cm^(-2).The full cell Si/CCP paired with Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2) cathode discharges a capacity of 199.0 mAh g^(-1) with 84.3%ICE at 0.1 C and the capacity retention of 95.6%after 100 cycles.This work validates the effectiveness of 3D polymer binder and provides new insights to boost the performance of Si anode.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1404201)Australia Research Council(Grant Nos.DP220100603 and FT220100559)+7 种基金the National Natural Science Foundation of China(Grant No.U23A20375)the Natural Science Foundation of Shanxi Province(Grant No.202403021211011)Research Project Supported by Shanxi Scholarship Council of China(Grant No.2024-032)Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(Grant No.20240006)the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices(Grant No.KF202402)Basic Scientific Research Conditions and Major Scientific Instrument and Equipment Development of Anhui Science and Technology Department(Grant No.2023YFF0715700)Key Research Project of Shanxi Province(Grant No.202302150101001)Linkage Project Scheme(Grant Nos.LP210200345 and LP210100467).
文摘Terahertz(THz)switches are essential components of THz communication systems.THz switches based on conventional waveguides and photonic crystal structures are sensitive to manufacturing defects and sharp bending,resulting in high scattering losses.In addition,THz switches with tunable working bandwidths have not yet been demonstrated.Here,we design THz switches based on a topological valley photonic crystal(VPC)structure using magnetic materials,which can achieve high forward transmittance based on the unique spin–valley locking effect.The broad working bandwidth allows selective turning on and off at a designed wavelength region by controlling the applied magnetic field.The designed THz switch can achieve an extinction ratio of up to 31.66 dB with an insertion loss of less than 0.13 dB.The 3-dB bandwidth is up to 49 GHz.This tunable THz switch can be experimentally fabricated by current fabrication techniques and thus can find broad applications in THz communication systems.
文摘Maximize the resource utilization efficiency and guarantee the quality of service(QoS)of users by selecting the network are the key issues for heterogeneous network operators,but the resources occupied by users in different networks cannot be compared directly.This paper proposes a network selection algorithm for heterogeneous network.Firstly,the concept of equivalent bandwidth is proposed,through which the actual resources occupied by users with certain QoS requirements in different networks can be compared directly.Then the concept of network applicability is defined to express the abilities of networks to support different services.The proposed network selection algorithm first evaluates whether the network has enough equivalent bandwidth required by the user and then prioritizes network with poor applicability to avoid the situation that there are still residual resources in entire network,but advanced services can not be admitted.The simulation results show that the proposed algorithm obtained better performance than the baselines in terms of reducing call blocking probability and improving network resource utilization efficiency.
基金supported by the Guizhou Provincial Science and Technology Projects for Platform and Talent Team Plan(No.GCC[2023]007)the Innovation Group of Guizhou University(No.[2024]08)+1 种基金Fok Ying Tung Education Foundation(No.171095)the National Natural Science Foundation of China(No.11964006).
文摘In recent years,two-dimensional layered transition metal dichalcogenides-based multicomponent com-posites(MCCs)acting as electromagnetic wave(EMW)materials have received intensive investiga-tions.However,the vulcanication of metal greatly hindered their enhancement of EMW absorption per-formances(EMWAPs).Herein,a combined metal-organic frameworks-derived and hydrothermal strat-egy was presented to produce yolk-shell structure(YSS)CoNi@Air@C@MoS_(2) MCCs.The results showed that the thermal and hydrothermal treatments resulted in the generation of YSS and two-dimensional MoS_(2) nanosheets,which maintained the original morphology of CoNi Prussian blue analogues.The pro-tection of thick C layer well inhibited the vulcanization of inner CoNi alloy.The formed sheet-like MoS_(2) further optimized impedance matching characteristics,which led to the satisfactory EMWAPs of CoNi@Air@C@MoS_(2) MCCs.Furthermore,the EMWAPs could be further improved by optimizing the Ni:Co atom ratios CoNi@Air@C@MoS_(2) MCCs,which stemmed from their boosted impedance matching perfor-mances,EMW attention and polarization loss abilities.The absorption bandwidth and reflection loss val-ues for YSS CoNi@Air@C@MoS_(2) MCCs are 8 GHz and−60.83 dB,which covered almost all C-Ku bands.In general,our research work provided a valid strategy to produce YSS magnetic CoNi@Air@C@MoS_(2) MCCs with high efficiency,which well avoided the vulcanization of metal nanoparticles,made best of hollow engineering and atomic ratio optimization strategy to boost the comprehensive EMWAPs.
基金supported by the open fund from Key Lab of Eco-restoration of Regional Contaminated Environment(Shenyang University),Ministry of Education(No.KF-22-08)the National Natural Science Foundation of China(Nos.22003074 and 42177406)+1 种基金the Youth Innovation Promotion Association CAS,Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011410)S.Liu gratefully acknowledges the financial support by the National Natural Science Foundation of China(No.52302223).
文摘Typical p-n junctions have emerged as a promising strategy for contending with charge carrier recombination in solar conversion.However,the photo-corrosion and unsuitable energy band positions still hinder their practical application for hydrogen production from water in photoelectrochemical systems.Here,an in-situ photo-oxidation method is proposed for achieving self-adapting activation of BiVO_(4)-based photoanodes with surface-encapsulated CuGaS_(2)particles by the ZnO layer.The self-adapting activation demotes the energy band positions of CuGaS_(2),establishing an S-scheme structure with BiVO_(4),resulting in an efficient p-n junction photoanode.The optimal sample exhibits enhanced photocurrent and an onset potential cathodically shifted by~300 mV compared with BiVO_(4),which is attributed to significantly enhanced charge transport and transfer efficiencies.As expected,it attains the highest photocurrent value of 5.87 mA·cm^(-2),aided by a hole scavenger at 1.23 V versus a reversible hydrogen electrode,which significantly surpasses that of BiVO_(4)(4.32 mA·cm^(-2)).
基金supported by the National Natural Science Foundation of China(Grant No.61975107)the Natural Science Foundation of Shanghai(Grant Nos.24ZR1422000 and 20ZR1471500),and the“111”Project(Grant No.D20031).
文摘Ultra-narrow bandwidth mode-locked lasers with tunable pulse duration can be versatile light sources for diverse applications.However,the spectral-temporal control of a narrow bandwidth mode-locked laser is challenging due to limited gain and nonlinearity,hindering practical applications of such lasers.We demonstrate a pulse duration widely tunable mode-locked ultra-narrow bandwidth laser using a composite filtering mechanism and a single-wall carbon nanotube.The laser pulse duration can be adjusted from 481 ps to 1.38 ns,which is the widest tuning range achieved in narrow-bandwidth passively mode-locked lasers.When the pulse duration is 1.38 ns,the corresponding spectral width reaches 4 pm(502 MHz).Numerical simulations support the experimental results and show that the evolution of long pulses in the laser cavity behaves similarly to a quasi-continuous wave with a low breathing ratio.We have not only designed a simple and flexible tunable scheme for the dilemma of spectral-temporal control in narrow-bandwidth mode-locked fiber lasers but also provided a unique and idealized light source for various applications that takes into account robust output.
文摘Following publication of the original article[1],the authors found that they pasted the same data when drawing XRD for sample NCO-1 and NCO-2 in Fig.2a,however,the XRD of all four samples in the manuscript was tested,and XRD raw data were kept and can be offered.The correct Fig.2 has been provided in this Correction.
基金supported partially by the National Natural Science Foundation(No.62473344)the T-Flight Laboratory in ShanXi Provincial(No.GSFC2024NBKY05)+1 种基金the Natural Science Basic Research Program of Shaanxi(No.2025JC-YBQN-035)the National Natural Science Foundation of China(Grant No.92471204).
文摘With the growing adoption of artificial intelligence algorithms and neural networks,online learning and adaptive methods for updating the bandwidth have become increasingly prevalent.However,the conditions required to ensure closed-loop stability when employing a time-varying bandwidth,as well as the supporting mathematical foundations,remain insufficiently studied.This paper investigates the stability condition for active disturbance rejection control(ADRC)with a time-varying bandwidth extended state observer(ESO).A new stability condition is derived,which means that the upper bound of rate of change for ESO bandwidth should be restricted.Moreover,under the proposed condition,the closed-loop stability of ADRC with a time-varying bandwidth observer is rigorously proved for nonlinear uncertainties.In simulations,the necessity of the proposed condition is illustrated,demonstrating that the rate of change of ESO bandwidth is crucial for closed-loop stability.
文摘The explosive growth of data traffic and heterogeneous service requirements of 5G networks—covering Enhanced Mobile Broadband(eMBB),Ultra-Reliable Low Latency Communication(URLLC),and Massive Machine Type Communication(mMTC)—present tremendous challenges to conventional methods of bandwidth allocation.A new deep reinforcement learning-based(DRL-based)bandwidth allocation system for real-time,dynamic management of 5G radio access networks is proposed in this paper.Unlike rule-based and static strategies,the proposed system dynamically updates itself according to shifting network conditions such as traffic load and channel conditions to maximize the achievable throughput,fairness,and compliance with QoS requirements.By using extensive simulations mimicking real-world 5G scenarios,the proposed DRL model outperforms current baselines like Long Short-Term Memory(LSTM),linear regression,round-robin,and greedy algorithms.It attains 90%–95%of the maximum theoretical achievable throughput and nearly twice the conventional equal allocation.It is also shown to react well under delay and reliability constraints,outperforming round-robin(hindered by excessive delay and packet loss)and proving to be more efficient than greedy approaches.In conclusion,the efficiency of DRL in optimizing the allocation of bandwidth is highlighted,and its potential to realize self-optimizing,Artificial Intelligence-assisted(AI-assisted)resource management in 5G as well as upcoming 6G networks is revealed.
