A least squares version of the recently proposed weighted twin support vector machine with local information(WLTSVM) for binary classification is formulated. This formulation leads to an extremely simple and fast algo...A least squares version of the recently proposed weighted twin support vector machine with local information(WLTSVM) for binary classification is formulated. This formulation leads to an extremely simple and fast algorithm, called least squares weighted twin support vector machine with local information(LSWLTSVM), for generating binary classifiers based on two non-parallel hyperplanes. Two modified primal problems of WLTSVM are attempted to solve, instead of two dual problems usually solved. The solution of the two modified problems reduces to solving just two systems of linear equations as opposed to solving two quadratic programming problems along with two systems of linear equations in WLTSVM. Moreover, two extra modifications were proposed in LSWLTSVM to improve the generalization capability. One is that a hot kernel function, not the simple-minded definition in WLTSVM, is used to define the weight matrix of adjacency graph, which ensures that the underlying similarity information between any pair of data points in the same class can be fully reflected. The other is that the weight for each point in the contrary class is considered in constructing equality constraints, which makes LSWLTSVM less sensitive to noise points than WLTSVM. Experimental results indicate that LSWLTSVM has comparable classification accuracy to that of WLTSVM but with remarkably less computational time.展开更多
Experimental teaching plays a crucial role in the trainings of students＇ abilities to analyze and solve problems. Therefore, it is very necessary to continuously carry out experiment teaching reform, improve experime...Experimental teaching plays a crucial role in the trainings of students＇ abilities to analyze and solve problems. Therefore, it is very necessary to continuously carry out experiment teaching reform, improve experiment teaching methods and means, and comprehensively open laboratories so as to provide students with more opportunities of doing experiments. To improve the teaching effect of electronic information experimental courses, a network interactive virtual experimental platform is developed. This platform allows students to finish the construction of all kinds of circuit structures and test virtual instruments in a simulation environment, upload experimental data and also interactively communicate with teachers through the lnternet. The platform can be applied to the teaching activities of related electronic information experimental courses, and also can be used as an aid teaching method for theory teachers. Therefore, it possesses a very good interactivity, and makes up the disadvantages of the experimental teaching in hardware environment, so that a feasible solution is provided for the opening of laboratories.展开更多
Previous studies have shown that deep learning is very effective in detecting known attacks.However,when facing unknown attacks,models such as Deep Neural Networks(DNN)combined with Long Short-Term Memory(LSTM),Convol...Previous studies have shown that deep learning is very effective in detecting known attacks.However,when facing unknown attacks,models such as Deep Neural Networks(DNN)combined with Long Short-Term Memory(LSTM),Convolutional Neural Networks(CNN)combined with LSTM,and so on are built by simple stacking,which has the problems of feature loss,low efficiency,and low accuracy.Therefore,this paper proposes an autonomous detectionmodel for Distributed Denial of Service attacks,Multi-Scale Convolutional Neural Network-Bidirectional Gated Recurrent Units-Single Headed Attention(MSCNN-BiGRU-SHA),which is based on a Multistrategy Integrated Zebra Optimization Algorithm(MI-ZOA).The model undergoes training and testing with the CICDDoS2019 dataset,and its performance is evaluated on a new GINKS2023 dataset.The hyperparameters for Conv_filter and GRU_unit are optimized using the Multi-strategy Integrated Zebra Optimization Algorithm(MIZOA).The experimental results show that the test accuracy of the MSCNN-BiGRU-SHA model based on the MIZOA proposed in this paper is as high as 0.9971 in the CICDDoS 2019 dataset.The evaluation accuracy of the new dataset GINKS2023 created in this paper is 0.9386.Compared to the MSCNN-BiGRU-SHA model based on the Zebra Optimization Algorithm(ZOA),the detection accuracy on the GINKS2023 dataset has improved by 5.81%,precisionhas increasedby 1.35%,the recallhas improvedby 9%,and theF1scorehas increasedby 5.55%.Compared to the MSCNN-BiGRU-SHA models developed using Grid Search,Random Search,and Bayesian Optimization,the MSCNN-BiGRU-SHA model optimized with the MI-ZOA exhibits better performance in terms of accuracy,precision,recall,and F1 score.展开更多
Multispectral imaging plays a crucial role in simultaneously capturing detailed spatial and spectral information,which is fundamental for understanding complex phenomena across various domains.Traditional systems face...Multispectral imaging plays a crucial role in simultaneously capturing detailed spatial and spectral information,which is fundamental for understanding complex phenomena across various domains.Traditional systems face significant challenges,such as large volume,static function,and limited wavelength selectivity.Here,we propose an innovative dynamic reflective multispectral imaging system via a thermally responsive cholesteric liquid crystal based planar lens.By employing advanced photoalignment technology,the phase distribution of a lens is imprinted to the liquid crystal director.The reflection band is reversibly tuned from 450 nm to 750 nm by thermally controlling the helical pitch of the cholesteric liquid crystal,allowing selectively capturing images in different colors.This capability increases imaging versatility,showing great potential in precision agriculture for assessing crop health,noninvasive diagnostics in healthcare,and advanced remote sensing for environmental monitoring.展开更多
Sodium metal has been widely studied in the field of batteries due to its high theoretical specific capacity(~1,166 m Ah/g),low redox potential(-2.71 V compared to standard hydrogen electrode),and lowcost advantages.H...Sodium metal has been widely studied in the field of batteries due to its high theoretical specific capacity(~1,166 m Ah/g),low redox potential(-2.71 V compared to standard hydrogen electrode),and lowcost advantages.However,problems such as unstable solid electrolyte interface(SEI),uncontrolled dendrite growth,and side reactions between solid-liquid interfaces have hindered the practical application of sodium metal anodes(SMAs).Currently,lots of strategies have been developed to achieve stabilized sodium metal anodes.Among these strategies,modified metal current collectors(MCCs)stand out due to their unique role in accommodating volumetric fluctuations with superior structure,lowering the energy barrier for sodium nucleation,and providing guided uniform sodium deposition.In this review,we first introduced three common metal-based current collectors applied to SMAs.Then,we summarized strategies to improve sodium deposition behavior by optimally engineering the surface of MCCs,including surface loading,surface structural design,and surface engineering for functional modification.We have followed the latest research progress and summarized surface optimization cases on different MCCs and their applications in battery systems.展开更多
High-performance and low-cost anode materials are critical for superior sodium-ion batteries(SIBs).Herein,high-yield porous carbon nanofiber(CNF)anode materials(named CNFs@Cu–Ni)are prepared by chemical vapor deposit...High-performance and low-cost anode materials are critical for superior sodium-ion batteries(SIBs).Herein,high-yield porous carbon nanofiber(CNF)anode materials(named CNFs@Cu–Ni)are prepared by chemical vapor deposition using a specialized nanoporous Cu–Ni alloy catalyst.Density functional theory calculations indicate that Ni incorporation results in a shift of the d-band center of the catalyst from−2.34157 to−1.93682 eV.This phenomenon elucidates the remarkable adsorption capacity of the Cu–Ni catalyst toward C2H2,thereby facilitating the catalytic growth of high-performance CNFs.With this approach,a superior yield of 258.6%for deposited carbon is reached after growth for 1 h.The CNFs@Cu–Ni anode presents an outstanding discharge capacity of 193.6 mAh·g^(−1) at 1.0 A·g^(−1)over 1000 cycles and an exceptional rate capability by maintaining a capacity of 158.9 mAh·g^(−1)even at 5.0 A·g^(−1)in an ether-based electrolyte.It also exhibits excellent performance in the CNFs@Cu–Ni//NVP full battery attributed to the presence of abundant Na+adsorption sites on its surface.This study presents a new concept for the advancement of high-performance carbonaceous electrodes for SIBs.展开更多
Two-dimensional(2D)metal oxides(2DMOs),such as MoO_(2),have made impressive strides in recent years,and their applicability in a number of fields such as electronic devices,optoelectronic devices and lasers has been d...Two-dimensional(2D)metal oxides(2DMOs),such as MoO_(2),have made impressive strides in recent years,and their applicability in a number of fields such as electronic devices,optoelectronic devices and lasers has been demonstrated.However,2DMOs present challenges in their synthesis using conventional methods due to their non-van der Waals nature.We report that KCl acts as a flux to prepare large-area 2DMOs with sub-millimeter scale.We systematically investigate the effects of temperature,homogeneous time and cooling rate on the products in the flux method,demonstrating that in this reaction a saturated homogenous solution is obtained upon the melting of the salt and precursor.Afterward,the cooling rate was adjusted to regulate the thickness of the target crystals,leading to the precipitation of 2D non-layered material from the supersaturated solution;by applying this method,the highly crystalline non-layered 2D MoO_(2)flakes with so far the largest lateral size of up to sub-millimeter scale(~464μm)were yielded.Electrical studies have revealed that the 2D MoO_(2)features metallic properties,with an excellent sheet resistance as low as 99Ω·square^(-1 )at room temperature,and exhibits a property of charge density wave in the measurement of resistivity as a function of temperature.展开更多
Data assimilation in agricultural remote sensing research is of great significance to integrate with remote sensing observations and model simulations for parameters estimation. The present investigation not only desi...Data assimilation in agricultural remote sensing research is of great significance to integrate with remote sensing observations and model simulations for parameters estimation. The present investigation not only designed and realized the Ensemble Kalman Filtering algorithm （EnKF） assimilation by combing the crop growth model （CERES-Wheat） with remote sensing data, but also optimized and updated the key parameters （LAI） of winter wheat by using remote sensing data. Results showed that the assimilation LAI and the observation ones agreed with each other, and the R2 reached 0.8315. So assimilation remote sensing and crop model could provide reference data for the agricultural production.展开更多
In order to improve the prediction accuracy of compressive strength of concrete,103 groups of concrete data were collected as the samples.We selected seven kinds of ingredients from the concrete samples, using Grid-SV...In order to improve the prediction accuracy of compressive strength of concrete,103 groups of concrete data were collected as the samples.We selected seven kinds of ingredients from the concrete samples, using Grid-SVM, PSO-SVM, and GA-SVM models to establish the prediction model of cubic meter compressive strength of concrete.The experimental results show that SVM model based on Grid optimization algorithm,SVM model based on Particle swarm optimization algorithm,SVM model based on Genetic optimization algorithm mean square error respectively are 0.001, 0.489 8, and 0.304 2, correlation coefficients are 0.994 8, 0.994 6, and 0.993 0. It is shown that cubic meter compressive strength prediction method based on Grid-SVM model is the best optimization algorithm.展开更多
The Boolean functions in an affine equivalence class are of the same algebraicdegree and nonlinearity, but may satisfy different order of correlation immunity and propa-gation criterion. A method is presented in this ...The Boolean functions in an affine equivalence class are of the same algebraicdegree and nonlinearity, but may satisfy different order of correlation immunity and propa-gation criterion. A method is presented in this paper to find Boolean functions with higherorder correlation immunity or satisfying higher order propagation criterion in an affine equiv-alence class. 8 AES s-box functions are not better Boolean functions in their affine equiva-lence class.展开更多
Due to the highly porous structure,large specific surface area,and 3 D interconnected metal conductive network,nanoporous metal foams have attracted a lot of attention in the field of energy conversion and storage,esp...Due to the highly porous structure,large specific surface area,and 3 D interconnected metal conductive network,nanoporous metal foams have attracted a lot of attention in the field of energy conversion and storage,especially lithium-ion batteries,which are ideal for current collectors.In this work,we develop a facile approach to fabricate core-shell Ni3Se2/Ni nanofoams composites.The Ni3Se2/Ni composites make full use of both the advantages of metal conductive network and core-shell structure,resulting in a high capacity and superior rate performance.In addition,the composites can be directly converted into electrode by a simple mechanical compression,which is more convenient than traditional casting method.What’s more,this material and its structure can be extended to other devices in the field of energy conversion and storage.展开更多
Incorporating four cations into a single-phase oxide is beneficial for maintaining structural stability during Li+insertion/desertion because of the produced entropy-dominated phase stabilization effects. However,medi...Incorporating four cations into a single-phase oxide is beneficial for maintaining structural stability during Li+insertion/desertion because of the produced entropy-dominated phase stabilization effects. However,medium-entropy oxides exhibit inherently poor electron and ion conductivity. As such, in this work, a single-phase medium-entropy oxide of Ni_(x)Cu_(y)CozMn_(1-x-y-z)O(named as NCCM@oxides(H_(2))) is prepared by modified-NiCuCoMn alloy through the epitaxial-growing-based self-combustion and hydrogen reduction. During hydrogen reduction, some Cu ions are reduced to elemental Cu(defined as Cu^(0)),which is distributed among the metal oxides, while generating extensive oxygen vacancies around Cu. The synergetic effect between nanoporous metal-core oxide-shell structure and enriched oxygen/Cu^(0) vacancies greatly enhances the electronic/ionic conductivity. In addition, the lattice of single-phase quaternary metal oxides has the configuration entropy stability, which enables the rock-salt structure to remain stable during repeated conversion reactions. Benefiting from the above-mentioned merits, the anodeforLi-ionbatterieswithentropy-stabled NCCM@oxides(H_(2)) composite shows a high specific capacity of 699 mAh·g^(-1) at 0.1 A·g^(-1) and ultra-stable cycling stability, which maintains 618 and 489 mAh·g^(-1) at 0.1 and 1.0 A·g^(-1) after 200 cycles, respectively. This is the first use of this novel and simple strategy for modifying medium-entropy oxides, which paves the way for the development of high-entropy oxides as high-performance electrodes.展开更多
Recently, many image encryption algorithms based on chaos have been proposed. Most of the previous algorithms encrypt components R, G, and B of color images independently and neglect the high correlation between them....Recently, many image encryption algorithms based on chaos have been proposed. Most of the previous algorithms encrypt components R, G, and B of color images independently and neglect the high correlation between them. In the paper, a novel color image encryption algorithm is introduced. The 24 bit planes of components R, G, and B of the color plain image are obtained and recombined into 4 compound bit planes, and this can make the three components affect each other. A four-dimensional(4D) memristive hyperchaotic system generates the pseudorandom key streams and its initial values come from the SHA 256 hash value of the color plain image. The compound bit planes and key streams are confused according to the principles of genetic recombination, then confusion and diffusion as a union are applied to the bit planes,and the color cipher image is obtained. Experimental results and security analyses demonstrate that the proposed algorithm is secure and effective so that it may be adopted for secure communication.展开更多
In computer vision fields,3D object recognition is one of the most important tasks for many real-world applications.Three-dimensional convolutional neural networks(CNNs)have demonstrated their advantages in 3D object ...In computer vision fields,3D object recognition is one of the most important tasks for many real-world applications.Three-dimensional convolutional neural networks(CNNs)have demonstrated their advantages in 3D object recognition.In this paper,we propose to use the principal curvature directions of 3D objects(using a CAD model)to represent the geometric features as inputs for the 3D CNN.Our framework,namely CurveNet,learns perceptually relevant salient features and predicts object class labels.Curvature directions incorporate complex surface information of a 3D object,which helps our framework to produce more precise and discriminative features for object recognition.Multitask learning is inspired by sharing features between two related tasks,where we consider pose classification as an auxiliary task to enable our CurveNet to better generalize object label classification.Experimental results show that our proposed framework using curvature vectors performs better than voxels as an input for 3D object classification.We further improved the performance of CurveNet by combining two networks with both curvature direction and voxels of a 3D object as the inputs.A Cross-Stitch module was adopted to learn effective shared features across multiple representations.We evaluated our methods using three publicly available datasets and achieved competitive performance in the 3D object recognition task.展开更多
Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Th...Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Things microdevice.However,the volatility in high vacuum and intrinsic sluggish kinetics of S hinder researchers from empirically integrating it into allsolid-state thin-film batteries,leading to inexperience in fabricating all-solid-state thin-film Li-S batteries(TFLSBs).Herein,for the first time,TFLSBs have been successfully constructed by stacking vertical graphene nanosheets-Li2S(VGsLi2S)composite thin-film cathode,lithium-phosphorous-oxynitride(LiPON)thin-film solid electrolyte,and Li metal anode.Fundamentally eliminating Lipolysulfide shuttle effect and maintaining a stable VGs-Li2S/LiPON interface upon prolonged cycles have been well identified by employing the solid-state Li-S system with an“unlimited Li”reservoir,which exhibits excellent longterm cycling stability with a capacity retention of 81%for 3,000 cycles,and an exceptional high temperature tolerance up to 60℃.More impressively,VGs-Li2S-based TFLSBs with evaporated-Li thin-film anode also demonstrate outstanding cycling performance over 500 cycles with a high Coulombic efficiency of 99.71%.Collectively,this study presents a new development strategy for secure and high-performance rechargeable all-solid-state thin-film batteries.展开更多
In this paper,the model predictive control based on the state estimation for a constrained system isinvestigated.By modifying the constraints for the predictive state,the control sequence becomes feasiblefor the real ...In this paper,the model predictive control based on the state estimation for a constrained system isinvestigated.By modifying the constraints for the predictive state,the control sequence becomes feasiblefor the real system,i.e.,the system state is guaranteed to be in the constraint domain.It s also provedthat the close-loop system is asymptotically stable and the system state converges to the origin.The conclusionis verified through simulation.展开更多
In cone-beam computed tomography （CBCT）, there are often cases where the size of the specimen is larger than the field of view （FOV） （referred to as over FOV-sized （OFS））. To acquire the complete projection da...In cone-beam computed tomography （CBCT）, there are often cases where the size of the specimen is larger than the field of view （FOV） （referred to as over FOV-sized （OFS））. To acquire the complete projection data for OFS objects, some scan modes have been developed for long objects and short but over-wide objects. However, these modes still cannot meet the requirements for both longitudinally long and transversely wide objects. In this paper, we propose a multiple helical scan mode and a corresponding reconstruction algorithm for both longitudinally long and transversely wide objects. The simulation results show that our model can deal with the problem and that the results are acceptable, while the OFS object is twice as long compared with the FOV in the same latitude.展开更多
The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to...The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to passivate defects in CZTSSe films.Herein,we investigate Li doping effects by applying Li OH into CZTSSe precursor solutions,and verify that carrier transport is enhanced in the CZTSSe solar cells.Systematic characterizations demonstrate that Li doping can effectively passivate non-radiative recombination centers and reduce band tailings of the CZTSSe films,leading to the decrease in total defect density and the increase in separation distance between donor and acceptor.Fewer free carriers are trapped in the band tail states,which speeds up carrier transport and reduces the probability of deep-level defects capturing carriers.The charge recombination lifetime is about twice as long as that of the undoped CZTSSe device,implying the heterojunction interface recombination is also inhibited.Besides,Li doping can increase carrier concentration and enhance build-in voltage,leading to a better carrier collection.By adjusting the Li/(Li+Cu)ratio to 18%,the solar cell efficiency is increased significantly to 9.68%with the fill factor(FF)of 65.94%,which is the highest FF reported so far for the flexible CZTSSe solar cells.The increased efficiency is mainly attributed to the reduction of V_(oc)deficit and the improved CZTSSe/Cd S junction quality.These results open up a simple route to passivate non-radiative states and reduce the band tailings of the CZTSSe films and improve the efficiency of the flexible CZTSSe solar cells.展开更多
Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the ele...Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene(Gr)heterostructure using first-principles calculation.We find that four types of defective structures,N-in,N-out,Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air.Moreover,vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure.Finally,the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts.Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures.展开更多
Reducing the Schottky barrier height(SBH)and even achieving the transition from Schottky contacts to Ohmic contacts are key challenges of achieving high energy efficiency and high-performance power devices.In this pap...Reducing the Schottky barrier height(SBH)and even achieving the transition from Schottky contacts to Ohmic contacts are key challenges of achieving high energy efficiency and high-performance power devices.In this paper,the modulation effects of biaxial strain on the electronic properties and Schottky barrier of Mo Si_(2)N_(4)(MSN)/graphene and WSi_(2)N_(4)(WSN)/graphene heterojunctions are examined by using first principles calculations.After the construction of heterojunctions,the electronic structures of MSN,WSN,and graphene are well preserved.Herein,we show that by applying suitable external strain to a heterojunction stacked by MSN or WSN—an emerging two-dimensional(2D)semiconductor family with excellent mechanical properties—and graphene,the heterojunction can be transformed from Schottky ptype contacts into n-type contacts,even highly efficient Ohmic contacts,making it of critical importance to unleash the tremendous potentials of graphene-based van der Waals(vd W)heterojunctions.Not only are these findings invaluable for designing high-performance graphene-based electronic devices,but also they provide an effective route to realizing dynamic switching either between n-type and p-type Schottky contacts,or between Schottky contacts and Ohmic contacts.展开更多
基金Project(61105057)supported by the National Natural Science Foundation of ChinaProject(13KJB520024)supported by the Natural Science Foundation of Jiangsu Higher Education Institutes of ChinaProject supported by Jiangsu Province Qing Lan Project,China
文摘A least squares version of the recently proposed weighted twin support vector machine with local information(WLTSVM) for binary classification is formulated. This formulation leads to an extremely simple and fast algorithm, called least squares weighted twin support vector machine with local information(LSWLTSVM), for generating binary classifiers based on two non-parallel hyperplanes. Two modified primal problems of WLTSVM are attempted to solve, instead of two dual problems usually solved. The solution of the two modified problems reduces to solving just two systems of linear equations as opposed to solving two quadratic programming problems along with two systems of linear equations in WLTSVM. Moreover, two extra modifications were proposed in LSWLTSVM to improve the generalization capability. One is that a hot kernel function, not the simple-minded definition in WLTSVM, is used to define the weight matrix of adjacency graph, which ensures that the underlying similarity information between any pair of data points in the same class can be fully reflected. The other is that the weight for each point in the contrary class is considered in constructing equality constraints, which makes LSWLTSVM less sensitive to noise points than WLTSVM. Experimental results indicate that LSWLTSVM has comparable classification accuracy to that of WLTSVM but with remarkably less computational time.
文摘Experimental teaching plays a crucial role in the trainings of students＇ abilities to analyze and solve problems. Therefore, it is very necessary to continuously carry out experiment teaching reform, improve experiment teaching methods and means, and comprehensively open laboratories so as to provide students with more opportunities of doing experiments. To improve the teaching effect of electronic information experimental courses, a network interactive virtual experimental platform is developed. This platform allows students to finish the construction of all kinds of circuit structures and test virtual instruments in a simulation environment, upload experimental data and also interactively communicate with teachers through the lnternet. The platform can be applied to the teaching activities of related electronic information experimental courses, and also can be used as an aid teaching method for theory teachers. Therefore, it possesses a very good interactivity, and makes up the disadvantages of the experimental teaching in hardware environment, so that a feasible solution is provided for the opening of laboratories.
基金supported by Science and Technology Innovation Programfor Postgraduate Students in IDP Subsidized by Fundamental Research Funds for the Central Universities(Project No.ZY20240335)support of the Research Project of the Key Technology of Malicious Code Detection Based on Data Mining in APT Attack(Project No.2022IT173)the Research Project of the Big Data Sensitive Information Supervision Technology Based on Convolutional Neural Network(Project No.2022011033).
文摘Previous studies have shown that deep learning is very effective in detecting known attacks.However,when facing unknown attacks,models such as Deep Neural Networks(DNN)combined with Long Short-Term Memory(LSTM),Convolutional Neural Networks(CNN)combined with LSTM,and so on are built by simple stacking,which has the problems of feature loss,low efficiency,and low accuracy.Therefore,this paper proposes an autonomous detectionmodel for Distributed Denial of Service attacks,Multi-Scale Convolutional Neural Network-Bidirectional Gated Recurrent Units-Single Headed Attention(MSCNN-BiGRU-SHA),which is based on a Multistrategy Integrated Zebra Optimization Algorithm(MI-ZOA).The model undergoes training and testing with the CICDDoS2019 dataset,and its performance is evaluated on a new GINKS2023 dataset.The hyperparameters for Conv_filter and GRU_unit are optimized using the Multi-strategy Integrated Zebra Optimization Algorithm(MIZOA).The experimental results show that the test accuracy of the MSCNN-BiGRU-SHA model based on the MIZOA proposed in this paper is as high as 0.9971 in the CICDDoS 2019 dataset.The evaluation accuracy of the new dataset GINKS2023 created in this paper is 0.9386.Compared to the MSCNN-BiGRU-SHA model based on the Zebra Optimization Algorithm(ZOA),the detection accuracy on the GINKS2023 dataset has improved by 5.81%,precisionhas increasedby 1.35%,the recallhas improvedby 9%,and theF1scorehas increasedby 5.55%.Compared to the MSCNN-BiGRU-SHA models developed using Grid Search,Random Search,and Bayesian Optimization,the MSCNN-BiGRU-SHA model optimized with the MI-ZOA exhibits better performance in terms of accuracy,precision,recall,and F1 score.
基金supported by the National Key Research and Development Program of China(No.2022YFA1203700)the National Natural Science Foundation of China(NSFC)(Nos.62405129 and 62035008)+1 种基金the University Research Project of Guangzhou Education Bureau(No.202235053)the Natural Science Foundation of Jiangsu Province(No.BK20241197).
文摘Multispectral imaging plays a crucial role in simultaneously capturing detailed spatial and spectral information,which is fundamental for understanding complex phenomena across various domains.Traditional systems face significant challenges,such as large volume,static function,and limited wavelength selectivity.Here,we propose an innovative dynamic reflective multispectral imaging system via a thermally responsive cholesteric liquid crystal based planar lens.By employing advanced photoalignment technology,the phase distribution of a lens is imprinted to the liquid crystal director.The reflection band is reversibly tuned from 450 nm to 750 nm by thermally controlling the helical pitch of the cholesteric liquid crystal,allowing selectively capturing images in different colors.This capability increases imaging versatility,showing great potential in precision agriculture for assessing crop health,noninvasive diagnostics in healthcare,and advanced remote sensing for environmental monitoring.
基金supported by the National Natural Science Foundation of China(Nos.52102291,52271011,and 51701142)supported by a grant from the Cangzhou Institute of Tiangong University(No.TGCYY-F-0201)。
文摘Sodium metal has been widely studied in the field of batteries due to its high theoretical specific capacity(~1,166 m Ah/g),low redox potential(-2.71 V compared to standard hydrogen electrode),and lowcost advantages.However,problems such as unstable solid electrolyte interface(SEI),uncontrolled dendrite growth,and side reactions between solid-liquid interfaces have hindered the practical application of sodium metal anodes(SMAs).Currently,lots of strategies have been developed to achieve stabilized sodium metal anodes.Among these strategies,modified metal current collectors(MCCs)stand out due to their unique role in accommodating volumetric fluctuations with superior structure,lowering the energy barrier for sodium nucleation,and providing guided uniform sodium deposition.In this review,we first introduced three common metal-based current collectors applied to SMAs.Then,we summarized strategies to improve sodium deposition behavior by optimally engineering the surface of MCCs,including surface loading,surface structural design,and surface engineering for functional modification.We have followed the latest research progress and summarized surface optimization cases on different MCCs and their applications in battery systems.
基金financially supported by the National Natural Science Foundation of China(Nos.52271011 and 52102291)the Structure Design and Mass Preparation of High Stability and Low Cost PEM Hydroelectrolysis Non-Iridium Catalyst,China(No.KC22453)
文摘High-performance and low-cost anode materials are critical for superior sodium-ion batteries(SIBs).Herein,high-yield porous carbon nanofiber(CNF)anode materials(named CNFs@Cu–Ni)are prepared by chemical vapor deposition using a specialized nanoporous Cu–Ni alloy catalyst.Density functional theory calculations indicate that Ni incorporation results in a shift of the d-band center of the catalyst from−2.34157 to−1.93682 eV.This phenomenon elucidates the remarkable adsorption capacity of the Cu–Ni catalyst toward C2H2,thereby facilitating the catalytic growth of high-performance CNFs.With this approach,a superior yield of 258.6%for deposited carbon is reached after growth for 1 h.The CNFs@Cu–Ni anode presents an outstanding discharge capacity of 193.6 mAh·g^(−1) at 1.0 A·g^(−1)over 1000 cycles and an exceptional rate capability by maintaining a capacity of 158.9 mAh·g^(−1)even at 5.0 A·g^(−1)in an ether-based electrolyte.It also exhibits excellent performance in the CNFs@Cu–Ni//NVP full battery attributed to the presence of abundant Na+adsorption sites on its surface.This study presents a new concept for the advancement of high-performance carbonaceous electrodes for SIBs.
基金supported by the National Key Research and Development Program of China(Nos.2023YFB3608703 and 2023YFB3608700)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(Nos.2021ZZ122 and 2020ZZ110)Fujian provincial projects(Nos.2021HZ0114 and 2021J01583).
文摘Two-dimensional(2D)metal oxides(2DMOs),such as MoO_(2),have made impressive strides in recent years,and their applicability in a number of fields such as electronic devices,optoelectronic devices and lasers has been demonstrated.However,2DMOs present challenges in their synthesis using conventional methods due to their non-van der Waals nature.We report that KCl acts as a flux to prepare large-area 2DMOs with sub-millimeter scale.We systematically investigate the effects of temperature,homogeneous time and cooling rate on the products in the flux method,demonstrating that in this reaction a saturated homogenous solution is obtained upon the melting of the salt and precursor.Afterward,the cooling rate was adjusted to regulate the thickness of the target crystals,leading to the precipitation of 2D non-layered material from the supersaturated solution;by applying this method,the highly crystalline non-layered 2D MoO_(2)flakes with so far the largest lateral size of up to sub-millimeter scale(~464μm)were yielded.Electrical studies have revealed that the 2D MoO_(2)features metallic properties,with an excellent sheet resistance as low as 99Ω·square^(-1 )at room temperature,and exhibits a property of charge density wave in the measurement of resistivity as a function of temperature.
基金supported by the National Natural Science Foundation of China (40701120)the Beijing Natural Science Foundation, China (4092016)the Beijing Nova, China (2008B33)
文摘Data assimilation in agricultural remote sensing research is of great significance to integrate with remote sensing observations and model simulations for parameters estimation. The present investigation not only designed and realized the Ensemble Kalman Filtering algorithm （EnKF） assimilation by combing the crop growth model （CERES-Wheat） with remote sensing data, but also optimized and updated the key parameters （LAI） of winter wheat by using remote sensing data. Results showed that the assimilation LAI and the observation ones agreed with each other, and the R2 reached 0.8315. So assimilation remote sensing and crop model could provide reference data for the agricultural production.
基金Funded by Natioanl Natural Science Foundation of Chin a(Nos.2012BAJ11B00,41301588,41471339,41571514)the Center for Materials Research and Analysis,Wuhan University of Technology
文摘In order to improve the prediction accuracy of compressive strength of concrete,103 groups of concrete data were collected as the samples.We selected seven kinds of ingredients from the concrete samples, using Grid-SVM, PSO-SVM, and GA-SVM models to establish the prediction model of cubic meter compressive strength of concrete.The experimental results show that SVM model based on Grid optimization algorithm,SVM model based on Particle swarm optimization algorithm,SVM model based on Genetic optimization algorithm mean square error respectively are 0.001, 0.489 8, and 0.304 2, correlation coefficients are 0.994 8, 0.994 6, and 0.993 0. It is shown that cubic meter compressive strength prediction method based on Grid-SVM model is the best optimization algorithm.
文摘The Boolean functions in an affine equivalence class are of the same algebraicdegree and nonlinearity, but may satisfy different order of correlation immunity and propa-gation criterion. A method is presented in this paper to find Boolean functions with higherorder correlation immunity or satisfying higher order propagation criterion in an affine equiv-alence class. 8 AES s-box functions are not better Boolean functions in their affine equiva-lence class.
基金financially supported by the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University(ZQN-PY608)the Fujian Provincial Natural Science Foundation of China(No.2017J05008)the National Natural Science Foundation of China(No.11704071).
文摘Due to the highly porous structure,large specific surface area,and 3 D interconnected metal conductive network,nanoporous metal foams have attracted a lot of attention in the field of energy conversion and storage,especially lithium-ion batteries,which are ideal for current collectors.In this work,we develop a facile approach to fabricate core-shell Ni3Se2/Ni nanofoams composites.The Ni3Se2/Ni composites make full use of both the advantages of metal conductive network and core-shell structure,resulting in a high capacity and superior rate performance.In addition,the composites can be directly converted into electrode by a simple mechanical compression,which is more convenient than traditional casting method.What’s more,this material and its structure can be extended to other devices in the field of energy conversion and storage.
基金financially supported by the National Natural Science Foundation of China (Nos. 52271011, 52102291 and 51701142)。
文摘Incorporating four cations into a single-phase oxide is beneficial for maintaining structural stability during Li+insertion/desertion because of the produced entropy-dominated phase stabilization effects. However,medium-entropy oxides exhibit inherently poor electron and ion conductivity. As such, in this work, a single-phase medium-entropy oxide of Ni_(x)Cu_(y)CozMn_(1-x-y-z)O(named as NCCM@oxides(H_(2))) is prepared by modified-NiCuCoMn alloy through the epitaxial-growing-based self-combustion and hydrogen reduction. During hydrogen reduction, some Cu ions are reduced to elemental Cu(defined as Cu^(0)),which is distributed among the metal oxides, while generating extensive oxygen vacancies around Cu. The synergetic effect between nanoporous metal-core oxide-shell structure and enriched oxygen/Cu^(0) vacancies greatly enhances the electronic/ionic conductivity. In addition, the lattice of single-phase quaternary metal oxides has the configuration entropy stability, which enables the rock-salt structure to remain stable during repeated conversion reactions. Benefiting from the above-mentioned merits, the anodeforLi-ionbatterieswithentropy-stabled NCCM@oxides(H_(2)) composite shows a high specific capacity of 699 mAh·g^(-1) at 0.1 A·g^(-1) and ultra-stable cycling stability, which maintains 618 and 489 mAh·g^(-1) at 0.1 and 1.0 A·g^(-1) after 200 cycles, respectively. This is the first use of this novel and simple strategy for modifying medium-entropy oxides, which paves the way for the development of high-entropy oxides as high-performance electrodes.
基金supported by the National Natural Science Foundation of China(Grant Nos.61203094 and 61305042)the Natural Science Foundation of the United States(Grant Nos.CNS-1253424 and ECCS-1202225)+3 种基金the Science and Technology Foundation of Henan Province,China(Grant No.152102210048)the Foundation and Frontier Project of Henan Province,China(Grant No.162300410196)the Natural Science Foundation of Educational Committee of Henan Province,China(Grant No.14A413015)the Research Foundation of Henan University,China(Grant No.xxjc20140006)
文摘Recently, many image encryption algorithms based on chaos have been proposed. Most of the previous algorithms encrypt components R, G, and B of color images independently and neglect the high correlation between them. In the paper, a novel color image encryption algorithm is introduced. The 24 bit planes of components R, G, and B of the color plain image are obtained and recombined into 4 compound bit planes, and this can make the three components affect each other. A four-dimensional(4D) memristive hyperchaotic system generates the pseudorandom key streams and its initial values come from the SHA 256 hash value of the color plain image. The compound bit planes and key streams are confused according to the principles of genetic recombination, then confusion and diffusion as a union are applied to the bit planes,and the color cipher image is obtained. Experimental results and security analyses demonstrate that the proposed algorithm is secure and effective so that it may be adopted for secure communication.
基金This paper was partially supported by a project of the Shanghai Science and Technology Committee(18510760300)Anhui Natural Science Foundation(1908085MF178)Anhui Excellent Young Talents Support Program Project(gxyqZD2019069).
文摘In computer vision fields,3D object recognition is one of the most important tasks for many real-world applications.Three-dimensional convolutional neural networks(CNNs)have demonstrated their advantages in 3D object recognition.In this paper,we propose to use the principal curvature directions of 3D objects(using a CAD model)to represent the geometric features as inputs for the 3D CNN.Our framework,namely CurveNet,learns perceptually relevant salient features and predicts object class labels.Curvature directions incorporate complex surface information of a 3D object,which helps our framework to produce more precise and discriminative features for object recognition.Multitask learning is inspired by sharing features between two related tasks,where we consider pose classification as an auxiliary task to enable our CurveNet to better generalize object label classification.Experimental results show that our proposed framework using curvature vectors performs better than voxels as an input for 3D object classification.We further improved the performance of CurveNet by combining two networks with both curvature direction and voxels of a 3D object as the inputs.A Cross-Stitch module was adopted to learn effective shared features across multiple representations.We evaluated our methods using three publicly available datasets and achieved competitive performance in the 3D object recognition task.
基金supported by National Natural Science Foundation of China(No.U22A20118)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR146,2021ZZ122)Award Program for Fujian Minjiang Scholar Professorship。
文摘Lithium-sulfur(Li-S)system coupled with thin-film solid electrolyte as a novel high-energy micro-battery has enormous potential for complementing embedded energy harvesters to enable the autonomy of the Internet of Things microdevice.However,the volatility in high vacuum and intrinsic sluggish kinetics of S hinder researchers from empirically integrating it into allsolid-state thin-film batteries,leading to inexperience in fabricating all-solid-state thin-film Li-S batteries(TFLSBs).Herein,for the first time,TFLSBs have been successfully constructed by stacking vertical graphene nanosheets-Li2S(VGsLi2S)composite thin-film cathode,lithium-phosphorous-oxynitride(LiPON)thin-film solid electrolyte,and Li metal anode.Fundamentally eliminating Lipolysulfide shuttle effect and maintaining a stable VGs-Li2S/LiPON interface upon prolonged cycles have been well identified by employing the solid-state Li-S system with an“unlimited Li”reservoir,which exhibits excellent longterm cycling stability with a capacity retention of 81%for 3,000 cycles,and an exceptional high temperature tolerance up to 60℃.More impressively,VGs-Li2S-based TFLSBs with evaporated-Li thin-film anode also demonstrate outstanding cycling performance over 500 cycles with a high Coulombic efficiency of 99.71%.Collectively,this study presents a new development strategy for secure and high-performance rechargeable all-solid-state thin-film batteries.
基金Supported by the National Natural Science Foundation of China (No. 60604017)
文摘In this paper,the model predictive control based on the state estimation for a constrained system isinvestigated.By modifying the constraints for the predictive state,the control sequence becomes feasiblefor the real system,i.e.,the system state is guaranteed to be in the constraint domain.It s also provedthat the close-loop system is asymptotically stable and the system state converges to the origin.The conclusionis verified through simulation.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB707701)the National High Technology Research and Development Program of China (Grant No. 2009AA012200)the National Nature Science Foundation of China(Grant No. 30970722)
文摘In cone-beam computed tomography （CBCT）, there are often cases where the size of the specimen is larger than the field of view （FOV） （referred to as over FOV-sized （OFS））. To acquire the complete projection data for OFS objects, some scan modes have been developed for long objects and short but over-wide objects. However, these modes still cannot meet the requirements for both longitudinally long and transversely wide objects. In this paper, we propose a multiple helical scan mode and a corresponding reconstruction algorithm for both longitudinally long and transversely wide objects. The simulation results show that our model can deal with the problem and that the results are acceptable, while the OFS object is twice as long compared with the FOV in the same latitude.
基金supported by the National Natural Science Foundation of China(62074037,52002073)the Science and Technology Department of Fujian Province(2020I0006)+3 种基金the Natural Science Foundation of Fujian Province(2019J01218)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ124)the Education and Scientific Research Project of Fujian Province(JAT200372)the Scientific Research Project of Fujian Jiangxia University(JXZ2019006)。
文摘The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to passivate defects in CZTSSe films.Herein,we investigate Li doping effects by applying Li OH into CZTSSe precursor solutions,and verify that carrier transport is enhanced in the CZTSSe solar cells.Systematic characterizations demonstrate that Li doping can effectively passivate non-radiative recombination centers and reduce band tailings of the CZTSSe films,leading to the decrease in total defect density and the increase in separation distance between donor and acceptor.Fewer free carriers are trapped in the band tail states,which speeds up carrier transport and reduces the probability of deep-level defects capturing carriers.The charge recombination lifetime is about twice as long as that of the undoped CZTSSe device,implying the heterojunction interface recombination is also inhibited.Besides,Li doping can increase carrier concentration and enhance build-in voltage,leading to a better carrier collection.By adjusting the Li/(Li+Cu)ratio to 18%,the solar cell efficiency is increased significantly to 9.68%with the fill factor(FF)of 65.94%,which is the highest FF reported so far for the flexible CZTSSe solar cells.The increased efficiency is mainly attributed to the reduction of V_(oc)deficit and the improved CZTSSe/Cd S junction quality.These results open up a simple route to passivate non-radiative states and reduce the band tailings of the CZTSSe films and improve the efficiency of the flexible CZTSSe solar cells.
基金Project supported by the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University(Grant No.2020-520000-83-01-324061)the National Natural Science Foundation of China(Grant No.61264004)the High-level Creative Talent Training Program in Guizhou Province of China(Grant No.[2015]4015).
文摘Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene(Gr)heterostructure using first-principles calculation.We find that four types of defective structures,N-in,N-out,Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air.Moreover,vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure.Finally,the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts.Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures.
基金Project supported by the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University,China(Grant No.2020-52000083-01-324061)the National Natural Science Foundation of China(Grant No.61264004)the High-level Creative Talent Training Program in Guizhou Province,China(Grant No.[2015]4015)。
文摘Reducing the Schottky barrier height(SBH)and even achieving the transition from Schottky contacts to Ohmic contacts are key challenges of achieving high energy efficiency and high-performance power devices.In this paper,the modulation effects of biaxial strain on the electronic properties and Schottky barrier of Mo Si_(2)N_(4)(MSN)/graphene and WSi_(2)N_(4)(WSN)/graphene heterojunctions are examined by using first principles calculations.After the construction of heterojunctions,the electronic structures of MSN,WSN,and graphene are well preserved.Herein,we show that by applying suitable external strain to a heterojunction stacked by MSN or WSN—an emerging two-dimensional(2D)semiconductor family with excellent mechanical properties—and graphene,the heterojunction can be transformed from Schottky ptype contacts into n-type contacts,even highly efficient Ohmic contacts,making it of critical importance to unleash the tremendous potentials of graphene-based van der Waals(vd W)heterojunctions.Not only are these findings invaluable for designing high-performance graphene-based electronic devices,but also they provide an effective route to realizing dynamic switching either between n-type and p-type Schottky contacts,or between Schottky contacts and Ohmic contacts.
