The increasing popularity of the Internet and the widespread use of information technology have led to a rise in the number and sophistication of network attacks and security threats.Intrusion detection systems are cr...The increasing popularity of the Internet and the widespread use of information technology have led to a rise in the number and sophistication of network attacks and security threats.Intrusion detection systems are crucial to network security,playing a pivotal role in safeguarding networks from potential threats.However,in the context of an evolving landscape of sophisticated and elusive attacks,existing intrusion detection methodologies often overlook critical aspects such as changes in network topology over time and interactions between hosts.To address these issues,this paper proposes a real-time network intrusion detection method based on graph neural networks.The proposedmethod leverages the advantages of graph neural networks and employs a straightforward graph construction method to represent network traffic as dynamic graph-structured data.Additionally,a graph convolution operation with a multi-head attention mechanism is utilized to enhance the model’s ability to capture the intricate relationships within the graph structure comprehensively.Furthermore,it uses an integrated graph neural network to address dynamic graphs’structural and topological changes at different time points and the challenges of edge embedding in intrusion detection data.The edge classification problem is effectively transformed into node classification by employing a line graph data representation,which facilitates fine-grained intrusion detection tasks on dynamic graph node feature representations.The efficacy of the proposed method is evaluated using two commonly used intrusion detection datasets,UNSW-NB15 and NF-ToN-IoT-v2,and results are compared with previous studies in this field.The experimental results demonstrate that our proposed method achieves 99.3%and 99.96%accuracy on the two datasets,respectively,and outperforms the benchmark model in several evaluation metrics.展开更多
Carbon has been widely utilized as electrode in electrochemical energy storage,relying on the interaction between ions and electrode.The performance of a carbon electrode is determined by a variety of factors includin...Carbon has been widely utilized as electrode in electrochemical energy storage,relying on the interaction between ions and electrode.The performance of a carbon electrode is determined by a variety of factors including the structural features of carbon material and the behavior of ions adsorbed on the carbon surface in the specific environment.As the fundamental unit of graphitic carbons,graphene has been employed as a model to understand the energy storage mechanism of carbon materials through various experimental and computational methods,ex‐situ or in‐situ.In this article,we provide a succinct overview of the state‐of‐the‐art proceedings on the ion storage mechanism on graphene.Topics include the structure engineering of carbons,electric gating effect of ions,ion dynamics on the interface or in the confined space,and specifically lithium‐ion storage/reaction on graphene.Our aim is to facilitate the understanding of electrochemistry on carbon electrodes.展开更多
As one of the most important micro energy storage devices(MESDs),graphene-based micro-supercapacitors(G-MSCs)possess the advantages of excellent flexibility,long cycle life,affordability and high reliability.In most c...As one of the most important micro energy storage devices(MESDs),graphene-based micro-supercapacitors(G-MSCs)possess the advantages of excellent flexibility,long cycle life,affordability and high reliability.In most cases,constructing three-dimensional(3D)graphene networks is widely utilized to promote the permeation of electrolyte and enhance the utilization of active materials.In this work,conventional freeze-drying process is utilized in the fabrication of G-MSCs to constitute 3D interconnected networks micro-electrodes,and further by regulating the composition of inks,carbon spheres(CSs)at different mass loadings are introduced into the graphene scaffolds to further increase the active sites of the micro-electrodes.The fabricated all carbon-based MSC with the optimal mass loading of CSs(0.406 mg cm^(-2))exhibits a high specific areal capacitance of 17.01mF cm^(-2)at the scan rate of 10mV s^(-1)and a capacitance retention of 93.14%after 10000 cycles at the scan rate of 500 mV s^(-1).The proposed microfabrication process is facile and fully compatible with modern microtechnologies and will be highly suitable for large-scale production and integration.展开更多
Surface modification of graphene oxide(GO)is a powerful strategy to develop its energy density for electrochemical energy storage.However,pre-modified GO always exhibits unsatisfactory hydrophilia and its ink-relevant...Surface modification of graphene oxide(GO)is a powerful strategy to develop its energy density for electrochemical energy storage.However,pre-modified GO always exhibits unsatisfactory hydrophilia and its ink-relevant utilization is extremely limited.Although GO ink is widely utilized in fabricating micro energy storage devices via extrusion-based 3D-printing,simultaneously obtaining satisfactory hydrophilia and high energy density still remains a challenge.In this work,an in-situ surface engineering strategy was employed to enhance the performance of GO micro-supercapacitor chips.Three dimensionally printed GO micro-supercapacitor chips were treated with pyrrole monomer to achieve selective and spontaneous anchoring of polypyrrole on the microelectrodes without affecting interspaces between the finger electrodes.The interface-reinforced graphene scaffolds were edge-welded and exhibited a considerably improved specific capacitance,from 13.6 to 128.4 mF·cm^(-2).These results are expected to provide a new method for improving the performance of micro-supercapacitors derived from GO inks and further strengthen the practicability of 3D printing techniques in fabricating energy storage devices.展开更多
Hydroxylamine(NH_(2)OH),a vital but unstable industrial feedstock,is presently prepared under harsh conditions that cause environmental and energy concerns.Here,we report an electrochemical method to prepare oximes,wh...Hydroxylamine(NH_(2)OH),a vital but unstable industrial feedstock,is presently prepared under harsh conditions that cause environmental and energy concerns.Here,we report an electrochemical method to prepare oximes,which serve as precursors for NH_(2)OH after facile hydrolysis.The carbon-supported amorphous Mn electrocatalyst delivers a current density of~100 mA cm^(-2) with a Faradaic efficiency of 40.92%and a yield rate of 0.251 mmol cm^(-2)h^(-1) for formaldoxime(CH_(2)NOH)generation by using nitrate and formaldehyde as reactants.Formaldoxime can be easily released to produce NH_(2)OH via hydrolysis.Impressively,this method exhibits an economic advantage over conventional manufacturing based on techno-economic analysis.A series of control experiments,in situ characterizations,and theoretical simulations unveil the reaction mechanism via the spontaneous reaction between an aldehyde and*NH_(2)OH intermediate derived from nitrate electroreduction.The high activity of Mn originates from its inhibitory effects on the further reduction of key*NH_(2)OH intermediate.This strategy opens a sustainable and green way for NH_(2)OH synthesis under mild conditions using renewable energy.展开更多
文摘The increasing popularity of the Internet and the widespread use of information technology have led to a rise in the number and sophistication of network attacks and security threats.Intrusion detection systems are crucial to network security,playing a pivotal role in safeguarding networks from potential threats.However,in the context of an evolving landscape of sophisticated and elusive attacks,existing intrusion detection methodologies often overlook critical aspects such as changes in network topology over time and interactions between hosts.To address these issues,this paper proposes a real-time network intrusion detection method based on graph neural networks.The proposedmethod leverages the advantages of graph neural networks and employs a straightforward graph construction method to represent network traffic as dynamic graph-structured data.Additionally,a graph convolution operation with a multi-head attention mechanism is utilized to enhance the model’s ability to capture the intricate relationships within the graph structure comprehensively.Furthermore,it uses an integrated graph neural network to address dynamic graphs’structural and topological changes at different time points and the challenges of edge embedding in intrusion detection data.The edge classification problem is effectively transformed into node classification by employing a line graph data representation,which facilitates fine-grained intrusion detection tasks on dynamic graph node feature representations.The efficacy of the proposed method is evaluated using two commonly used intrusion detection datasets,UNSW-NB15 and NF-ToN-IoT-v2,and results are compared with previous studies in this field.The experimental results demonstrate that our proposed method achieves 99.3%and 99.96%accuracy on the two datasets,respectively,and outperforms the benchmark model in several evaluation metrics.
基金National Key Research and Development Program of China,Grant/Award Number:2020YFA0711502National Natural Science Foundation of China,Grant/Award Numbers:52273234,52273239,52325202。
文摘Carbon has been widely utilized as electrode in electrochemical energy storage,relying on the interaction between ions and electrode.The performance of a carbon electrode is determined by a variety of factors including the structural features of carbon material and the behavior of ions adsorbed on the carbon surface in the specific environment.As the fundamental unit of graphitic carbons,graphene has been employed as a model to understand the energy storage mechanism of carbon materials through various experimental and computational methods,ex‐situ or in‐situ.In this article,we provide a succinct overview of the state‐of‐the‐art proceedings on the ion storage mechanism on graphene.Topics include the structure engineering of carbons,electric gating effect of ions,ion dynamics on the interface or in the confined space,and specifically lithium‐ion storage/reaction on graphene.Our aim is to facilitate the understanding of electrochemistry on carbon electrodes.
基金This work was supported by the National Natural Science Fund for Distinguished Young Scholars(51425204)the National Natural Science Foundation of China(51521001,51502227,51579198,51802239)+6 种基金the National Key Research and Development Program of China(2016YFA0202603,2016YFA0202604)the Programme of Introducing Talents of Discipline to Universities(B17034)the China Postdoctoral Science Foundation(2015T80845)the Yellow Crane Talent(Science&Technology)Program of Wuhan Citythe Wuhan Morning Light Plan of Youth Science and Technology(No.2017050304010316)the Fundamental Research Funds for the Central Universities(WUT:2017III005,2017III009,2018IVA091)the Students innovation and entrepreneurship training program(WUT:20171049701005).
文摘As one of the most important micro energy storage devices(MESDs),graphene-based micro-supercapacitors(G-MSCs)possess the advantages of excellent flexibility,long cycle life,affordability and high reliability.In most cases,constructing three-dimensional(3D)graphene networks is widely utilized to promote the permeation of electrolyte and enhance the utilization of active materials.In this work,conventional freeze-drying process is utilized in the fabrication of G-MSCs to constitute 3D interconnected networks micro-electrodes,and further by regulating the composition of inks,carbon spheres(CSs)at different mass loadings are introduced into the graphene scaffolds to further increase the active sites of the micro-electrodes.The fabricated all carbon-based MSC with the optimal mass loading of CSs(0.406 mg cm^(-2))exhibits a high specific areal capacitance of 17.01mF cm^(-2)at the scan rate of 10mV s^(-1)and a capacitance retention of 93.14%after 10000 cycles at the scan rate of 500 mV s^(-1).The proposed microfabrication process is facile and fully compatible with modern microtechnologies and will be highly suitable for large-scale production and integration.
基金supported by the National Key Research and Development Program of China(No.2020YFA715000)the National Natural Science Foundation of China(No.51802239)+3 种基金the National Key Research and Development Program of China(No.2019YFA0704902)Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(Nos.XHT2020-005 and XHT2020-003)the Natural Science Foundation of Hubei Province(No.2019CFA001)the Fundamental Research Funds for the Central Universities(Nos.2020III011GX,2020IVB057,2019IVB054,2019III062JL,and 2019-YB-008).
文摘Surface modification of graphene oxide(GO)is a powerful strategy to develop its energy density for electrochemical energy storage.However,pre-modified GO always exhibits unsatisfactory hydrophilia and its ink-relevant utilization is extremely limited.Although GO ink is widely utilized in fabricating micro energy storage devices via extrusion-based 3D-printing,simultaneously obtaining satisfactory hydrophilia and high energy density still remains a challenge.In this work,an in-situ surface engineering strategy was employed to enhance the performance of GO micro-supercapacitor chips.Three dimensionally printed GO micro-supercapacitor chips were treated with pyrrole monomer to achieve selective and spontaneous anchoring of polypyrrole on the microelectrodes without affecting interspaces between the finger electrodes.The interface-reinforced graphene scaffolds were edge-welded and exhibited a considerably improved specific capacitance,from 13.6 to 128.4 mF·cm^(-2).These results are expected to provide a new method for improving the performance of micro-supercapacitors derived from GO inks and further strengthen the practicability of 3D printing techniques in fabricating energy storage devices.
基金supported by the National Natural Science Foundation of China(22271213(B.Z.)and 22071173(Y.Y.))the Haihe Laboratory of Sustainable Chemical Transformationsthe National Postdoctoral Science Foundation of China(2022M722357(Y.W.))。
文摘Hydroxylamine(NH_(2)OH),a vital but unstable industrial feedstock,is presently prepared under harsh conditions that cause environmental and energy concerns.Here,we report an electrochemical method to prepare oximes,which serve as precursors for NH_(2)OH after facile hydrolysis.The carbon-supported amorphous Mn electrocatalyst delivers a current density of~100 mA cm^(-2) with a Faradaic efficiency of 40.92%and a yield rate of 0.251 mmol cm^(-2)h^(-1) for formaldoxime(CH_(2)NOH)generation by using nitrate and formaldehyde as reactants.Formaldoxime can be easily released to produce NH_(2)OH via hydrolysis.Impressively,this method exhibits an economic advantage over conventional manufacturing based on techno-economic analysis.A series of control experiments,in situ characterizations,and theoretical simulations unveil the reaction mechanism via the spontaneous reaction between an aldehyde and*NH_(2)OH intermediate derived from nitrate electroreduction.The high activity of Mn originates from its inhibitory effects on the further reduction of key*NH_(2)OH intermediate.This strategy opens a sustainable and green way for NH_(2)OH synthesis under mild conditions using renewable energy.
