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Petrophysical interpretations of subsurface stratigraphic correlations,Baram Delta,Sarawak,Malaysia 被引量:2
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作者 Hisham Ben Mahmud Muhammad Hilmi Bin Muhammad Hisham +2 位作者 Walid Mohamed Mahmud Van Hong Leong Mian Umer Shafiq 《Energy Geoscience》 2020年第3期100-114,共15页
Petrophysical well log data help to predict hydrocarbon reserves before field development which involves huge financial commitment.In this study,reservoir characterization was performed with a view to obtain informati... Petrophysical well log data help to predict hydrocarbon reserves before field development which involves huge financial commitment.In this study,reservoir characterization was performed with a view to obtain information on the geological formation type and petrophysical parameters.Wireline log data obtained from five wells were used to develop a 3D model of X-field in the Baram Delta which was in turn evaluated using the PETREL software.Suites of gamma ray,sonic,density,resistivity and neutron logs aided the delineation and correlation of the sandstone formation.Fourteen hydrocarbon-bearing sands were defined from well log data and divided into two-reservoir zones,shallow and deep.Well correlation assisted in the delineation of the reservoir sands across the wells.The quality of the reservoir formation was evaluated from average petrophysical properties:with an average thickness of 62 m,an average porosity of 0.19,an average net-to-gross ratio of 0.068,an average V-shale of 0.45,and an average water saturation of 0.95.A rollover anticline structure was identified across the field using the fault as a description tool.Variation of petrophysical parameters and uncertainty in the reservoir properties were included to predict the effect on the volume of oil in place.This study revealed that the discovered hydrocarbon reserve resource accumulations in the Field X for the fourteen-mapped reservoir sands have a total proven reserve resource estimate of 740MMSTB at P90,655MMSTB at P50 and 593MMSTB at P10.Reservoirs A and B are the only intervals with the highest recoverable oil,a volume of 256MMSTB at P90,215MMSTB at P50 and 181MMSTB at P10,respectively.These analyses facilitated an improved reservoir description of shaly sandstone,which contributes to better planning of hydrocarbon re-development and future recovery,and thereby improving the energy supply security of the regions. 展开更多
关键词 Oil reserve Well logging Effective porosity Shale volume Water saturation Oil saturation
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Enhancing MXene-based supercapacitors:Role of synthesis and 3D architectures
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作者 Wen Siong Poh Wen Jie Yiang +2 位作者 Wee-Jun Ong Pau Loke Show Chuan Yi Foo 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期1-26,共26页
MXene has been the limelight for studies on electrode active materials,aiming at developing supercapacitors with boosted energy density to meet the emerging influx of wearable and portable electronic devices.Despite i... MXene has been the limelight for studies on electrode active materials,aiming at developing supercapacitors with boosted energy density to meet the emerging influx of wearable and portable electronic devices.Despite its various desirable properties including intrinsic flexibility,high specific surface area,excellent metallic conductivity and unique abundance of surface functionalities,its full potential for electrochemical performance is hindered by the notorious restacking phenomenon of MXene nanosheets.Ascribed to its two-dimensional(2D)nature and surface functional groups,inevitable Van der Waals interactions drive the agglomeration of nanosheets,ultimately reducing the exposure of electrochemically active sites to the electrolyte,as well as severely lengthening electrolyte ion transport pathways.As a result,energy and power density deteriorate,limiting the application versatility of MXene-based supercapacitors.Constructing 3D architectures using 2D nanosheets presents as a straightforward yet ingenious approach to mitigate the fatal flaws of MXene.However,the sheer number of distinct methodologies reported,thus far,calls for a systematic review that unravels the rationale behind such 3D MXene structural designs.Herein,this review aims to serve this purpose while also scrutinizing the structure–property relationship to correlate such structural modifications to their ensuing electrochemical performance enhancements.Besides,the physicochemical properties of MXene play fundamental roles in determining the effective charge storage capabilities of 3D MXene-based electrodes.This largely depends on different MXene synthesis techniques and synthesis condition variations,hence,elucidated in this review as well.Lastly,the challenges and perspectives for achieving viable commercialization of MXene-based supercapacitor electrodes are highlighted. 展开更多
关键词 MXene 3D architectures Synthesis design SUPERCAPACITOR Energy storage
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Synergistic dance of digital economy and green finance on carbon emissions:Insights from China
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作者 Ruiqi Wang Wenqi Zhao 《Chinese Journal of Population,Resources and Environment》 2024年第3期213-229,共17页
China has recently implemented a dual-carbon strategy to combat climate change and other environmental issues and is committed to modernizing it sustainably.This paper supports these goals and explores how the digital... China has recently implemented a dual-carbon strategy to combat climate change and other environmental issues and is committed to modernizing it sustainably.This paper supports these goals and explores how the digital economy and green finance intersect and impact carbon emissions.Using panel data from 30 Chinese provinces over the period 2011-2021,this paper finds that the digital economy and green finance can together reduce carbon emissions,and conducts several robustness tests supporting this conclusion.A heterogeneity analysis shows that these synergistic effects are more important in regions with low levels of social consumption Meanwhile,in the spatial dimension,the synergistic effect of the local digital economy and green finance adversely impacts the level of carbon emissions in surrounding areas.The findings of this paper provide insights for policymakers in guiding capital flow and implementing carbon-reduction policies while fostering the growth of China’s digital economy and environmental sustainability. 展开更多
关键词 Digital economy Green finance Carbon emission Dynamic spatial Durbin model Spatial spillover effect
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Stable Cycling of All-Solid-State Lithium Batteries Enabled by Cyano-Molecular Diamond Improved Polymer Electrolytes
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作者 Yang Dai Mengbing Zhuang +5 位作者 Yi-Xiao Deng Yuan Liao Jian Gu Tinglu Song Hao Yan Jin-Cheng Zheng 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第10期561-575,共15页
The interfacial instability of the poly(ethylene oxide)(PEO)-based electrolytes impedes the long-term cycling and further application of all-solid-state lithium metal batter-ies.In this work,we have shown an effective... The interfacial instability of the poly(ethylene oxide)(PEO)-based electrolytes impedes the long-term cycling and further application of all-solid-state lithium metal batter-ies.In this work,we have shown an effective additive 1-adaman-tanecarbonitrile,which con-tributes to the excellent per-formance of the poly(ethylene oxide)-based electrolytes.Owing to the strong interaction of the 1-Adamantanecarboni-trile to the polymer matrix and anions,the coordination of the Li^(+)-EO is weakened,and the binding effect of anions is strengthened,thereby improving the Li^(+)conductivity and the electrochemical stability.The diamond building block on the surface of the lithium anode can sup-press the growth of lithium dendrites.Importantly,the 1-Adamantanecarbonitrile also regulates the formation of LiF in the solid electrolyte interface and cathode electrolyte interface,which contributes to the interfacial stability(especially at high voltages)and protects the electrodes,enabling all-solid-state batteries to cycle at high voltages for long periods of time.Therefore,the Li/Li symmetric cell undergoes long-term lithium plating/stripping for more than 2000 h.1-Adamantanecarbonitrile-poly(ethylene oxide)-based LFP/Li and 4.3 V Ni_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li all-solid-state batteries achieved stable cycles for 1000 times,with capacity retention rates reaching 85%and 80%,respectively. 展开更多
关键词 1-Adamantanecarbonitrile(ADCN) Poly(ethylene oxide) All-solid-state batteries Interfacial stability High voltage
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Origin and evolution of a new tetraploid mangrove species in an intertidal zone
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作者 Hui Feng Achyut Kumar Banerjee +9 位作者 Wuxia Guo Yang Yuan Fuyuan Duan Wei Lun Ng Xuming Zhao Yuting Liu Chunmei Li Ying Liu Linfeng Li Yelin Huang 《Plant Diversity》 SCIE CAS CSCD 2024年第4期476-490,共15页
Polyploidy is a major factor in the evolution of plants,yet we know little about the origin and evolution of polyploidy in intertidal species.This study aimed to identify the evolutionary transitions in three truemang... Polyploidy is a major factor in the evolution of plants,yet we know little about the origin and evolution of polyploidy in intertidal species.This study aimed to identify the evolutionary transitions in three truemangrove species of the genus Acanthus distributed in the Indo-West Pacific region.For this purpose,we took an integrative approach that combined data on morphology,cytology,climatic niche,phylogeny,and biogeography of 493 samples from 42 geographic sites.Our results show that the Acanthus ilicifolius lineage distributed east of the Thai-Malay Peninsula possesses a tetraploid karyotype,which is morphologically distinct from that of the lineage on the west side.The haplotype networks and phylogenetic trees for the chloroplast genome and eight nuclear genes reveal that the tetraploid species has two sub-genomes,one each from A.ilicifolius and A.ebracteatus,the paternal and maternal parents,respectively.Population structure analysis also supports the hybrid speciation history of the new tetraploid species.The two sub-genomes of the tetraploid species diverged from their diploid progenitors during the Pleistocene.Environmental niche models revealed that the tetraploid species not only occupied the near-entire niche space of the diploids,but also expanded into novel environments.Our findings suggest that A.ilicifolius species distributed on the east side of the Thai-Malay Peninsula should be regarded as a new species,A.tetraploideus,which originated from hybridization between A.ilicifolius and A.ebracteatus,followed by chromosome doubling.This is the first report of a true-mangrove allopolyploid species that can reproduce sexually and clonally reproduction,which explains the long-term adaptive potential of the species. 展开更多
关键词 Acanthus ALLOPOLYPLOID BIOGEOGRAPHY EVOLUTION HYBRIDIZATION POLYPLOIDY
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Influence of shale reservoir properties on shale oil mobility and its mechanism
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作者 Jijun Li Hang You +6 位作者 Xinwen Zhang Suping Zhao Fujie Jiang Guoqi Feng Yue Su Yinwu Zhang Jiaheng Xue 《Energy Geoscience》 EI 2024年第4期212-223,共12页
Given the tremendous potential for continental shale oil in China,many oilfields in the central and eastern parts of the country are involved in the exploration and development of shale oil resources.Besides engineeri... Given the tremendous potential for continental shale oil in China,many oilfields in the central and eastern parts of the country are involved in the exploration and development of shale oil resources.Besides engineering factors,shale oil mobility is the key to determining its commercial viability.This study explores the Hetaoyuan Formation in the Biyang Depression as an example to determine the influence of reservoir properties on the movable oil volume and its mechanisms.Multiple techniques were used,including displacement nuclear magnetic resonance(NMR),low-temperature nitrogen adsorption(LTNA),X-ray diffraction(XRD)bulk mineral analysis,and scanning electron microscopy(SEM),and the results suggest that large average pore diameter,high throat to pore ratio,single pore morphology,and small specific surface area can weaken the boundary layer effect and reduce the amount of adsorbed oil.Our observations reveal that compared to the dissolution pores and intergranular pores in brittle minerals,the intercrystalline pores in terrigenous clastic clay minerals are more affected by compaction.Furthermore,authigenic clay minerals notably block the intergranular pores in the interbedded sandstones.Clay minerals are identified as the main contributor to the specific surface area,with high clay mineral content enhancing the pore heterogeneity of the reservoir.Thus,positive shale oil mobility occurs in shale with a weak boundary layer effect,which is attributed to the high brittle mineral content,large average pore diameter,small specific surface area,single pore morphology,and reservoir homogeneity. 展开更多
关键词 Biyang depression Hetaoyuan formation Shale oil MOBILITY Nuclear magnetic resonance
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先进光催化剂设计与制备 被引量:5
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作者 余家国 李鑫 +1 位作者 王伟俊 张留洋 《物理化学学报》 SCIE CAS CSCD 北大核心 2021年第6期1-2,共2页
光催化材料和技术在能源^(1,2)、环境、健康^(3,4)、生态建筑材料等领域具有广阔的应用前景,先进光催化剂的设计与制备是光催化领域的研究热点5。当前,光催化材料面临的最大挑战是低的光催化效率和快的光生电子和空穴复合。传统Ⅱ型异... 光催化材料和技术在能源^(1,2)、环境、健康^(3,4)、生态建筑材料等领域具有广阔的应用前景,先进光催化剂的设计与制备是光催化领域的研究热点5。当前,光催化材料面临的最大挑战是低的光催化效率和快的光生电子和空穴复合。传统Ⅱ型异质结光生载流子的还原氧化能力被极大削弱,热力学上并不利于光催化反应的进行。 展开更多
关键词 光催化材料 光生载流子 光催化剂 光催化反应 生态建筑材料 还原氧化 光催化效率 异质结
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氧化物钙钛矿的光催化研究进展:CO_(2)还原、水裂解、固氮 被引量:10
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作者 王则鉴 洪佳佳 +4 位作者 Sue-Faye Ng 刘雯 黄俊杰 陈鹏飞 Wee-Jun Ong 《物理化学学报》 SCIE CAS CSCD 北大核心 2021年第6期76-106,共31页
在寻求可再生能源供应及解决环境问题的迫切需求下,光电、光催化、电催化等领域中多种技术被开发以解决这一迫切问题。其中,光催化技术因其可将清洁太阳能转化为化学燃料的优越能力而备受关注。在层出不穷的光催化材料中,具有阳离子可... 在寻求可再生能源供应及解决环境问题的迫切需求下,光电、光催化、电催化等领域中多种技术被开发以解决这一迫切问题。其中,光催化技术因其可将清洁太阳能转化为化学燃料的优越能力而备受关注。在层出不穷的光催化材料中,具有阳离子可替代性的钙钛矿氧化物(ABO_3)在电子信息、太阳能电池和光催化等领域具有极大的潜力。由于这类材料具有活性高、成本低、稳定性好、结构易调控等独特性能,钙钛矿氧化物光催化剂在水分解、二氧化碳还原转化、固氮等方面取得了广泛的应用。本文综述了光催化的结构与合成方法,重点介绍了光催化的应用,最后展望了光催化的未来发展前景。 展开更多
关键词 氧化物钙钛矿 光催化 二氧化碳还原 水裂解 固氮
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Interfacial engineering of graphitic carbon nitride(g-C_3N_4)-based metal sulfide heterojunction photocatalysts for energy conversion: A review 被引量:37
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作者 Yijie Ren Deqian Zeng Wee-Jun Ong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第3期289-319,共31页
As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemic... As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future. 展开更多
关键词 Graphitic carbon nitride Metal sulfide PHOTOCATALYSIS Energy transformation Water splitting Reduction of carbon dioxide Pollutant degradation Nitrogen fixation
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Point-to-face contact heterojunctions:Interfacial design of 0D nanomaterials on 2D g-C_(3)N_(4)towards photocatalytic energy applications 被引量:12
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作者 Xin-Quan Tan Sue-Faye Ng +1 位作者 Abdul Rahman Mohamed Wee-Jun Ong 《Carbon Energy》 SCIE CAS 2022年第5期665-730,共66页
Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality.Photocatalysis,a process that trans... Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality.Photocatalysis,a process that transforms solar energy into clean fuels through a photocatalyst,represents a felicitous direction toward sustainability.Eco-rich metal-free graphitic carbon nitride(g-C_(3)N_(4))is profiled as an attractive photocatalyst due to its fascinating properties,including excellent chemical and thermal stability,moderate band gap,visible light-active nature,and ease of fabrication.Nonetheless,the shortcomings of g-C_(3)N_(4)include fast charge recombination and limited surface-active sites,which adversely affect photocatalytic reactions.Among the modification strategies,point-to-face contact engineering of 2D g-C_(3)N_(4)with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area,short effective charge-transfer pathways,and quantum confinement effects.This review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g-C_(3)N_(4)in the construction of point-to-face heterojunction interfaces.Notably,0D materials such as metals,metal oxides,metal sulfides,metal selenides,metal phosphides,and nonmetals on g-C_(3)N_(4)with different charge-transfer mechanisms are systematically discussed along with controllable synthesis strategies.The applications of 0D/2D g-C_(3)N_(4)-based photocatalysts are focused on solar-to-energy conversion via the hydrogen evolution reaction,the CO_(2)reduction reaction,and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction pathways.Finally,future perspectives for developing high-efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes,large-scale production,machine learning integration,and multidisciplinary advances for technological breakthroughs. 展开更多
关键词 0D/2D heterojunction charge-transfer mechanisms g-C_(3)N_(4)nanosheets heterojunction interface photocatalysis solar-to-energy conversion
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Insights into electrochemical nitrogen reduction reaction mechanisms:Combined effect of single transition-metal and boron atom 被引量:5
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作者 Xingzhu Chen Wee-Jun Ong +2 位作者 Xiujian Zhao Peng Zhang Neng Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第7期577-585,共9页
Developing single-atom catalysts(SACs) for electrochemical devices is a frontier in energy conversion.The comparison of stability,activity and selectivity between various single atoms is one of the main research focus... Developing single-atom catalysts(SACs) for electrochemical devices is a frontier in energy conversion.The comparison of stability,activity and selectivity between various single atoms is one of the main research focuses in SACs.However,the in-depth understanding of the role that the coordination atoms of single atom play in the catalytic process is lacking.Herein,we proposed a graphene-like boroncarbon-nitride(BCN) monolayer as the support of single metal atom.The electrocatalytic nitrogen reduction reaction(eNRR) performances of 3 d,4 d transition metal(TM) atoms embedded in defective BCN were systematically investigated by means of density functional theory(DFT) computations.Our study shows that the TM-to-N and B-to-N π-back bonding can contribute to the activation of N_(2).Importantly,a combined effect is revealed between single TM atom and boron atom on eNRR:TM atom enhances the nitrogen reduction process especially in facilitating the N_(2) adsorption and the NH3 desorption,while boron atom modulates the bonding strength of key intermediates by balancing the charged species.Furthermore,Nb@BN3 possesses the highest electrocata lytic activity with limiting potential of-0.49 V,and exhibits a high selectivity for nitrogen reduction reaction(NRR) to ammonia compared with hydrogen evolution reaction(HER).As such,this work can stimulate a research doorway for designing multi-active sites of the anchored single atoms and the innate atoms of substrate based on the mechanistic insights to guide future eNRR research. 展开更多
关键词 Boron-carbon–nitrogen(BCN) Single-atom catalysts Electrocatalytic nitrogen reduction reaction Density functional theory Combined effect
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Enhancement of thermal rectification by asymmetry engineering of thermal conductivity and geometric structure for multi-segment thermal rectifier 被引量:1
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作者 杜甫烨 张望 +1 位作者 王惠琼 郑金成 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期34-43,共10页
Thermal rectification is an exotic thermal transport phenomenon,an analog to electrical rectification,in which heat flux along one direction is larger than that in the other direction and is of significant interest in... Thermal rectification is an exotic thermal transport phenomenon,an analog to electrical rectification,in which heat flux along one direction is larger than that in the other direction and is of significant interest in electronic device applications.However,achieving high thermal rectification efficiency or rectification ratio is still a scientific challenge.In this work,we performed a systematic simulation of thermal rectification by considering both efforts of thermal conductivity asymmetry and geometrical asymmetry in a multi-segment thermal rectifier.It is found that the high asymmetry of thermal conductivity and the asymmetry of the geometric structure of multi-segment thermal rectifiers can significantly enhance the thermal rectification,and the combination of both thermal conductivity asymmetry and geometrical asymmetry can further improve thermal rectification efficiency.This work suggests a possible way for improving thermal rectification devices by asymmetry engineering. 展开更多
关键词 thermal conductivity SIMULATION thermal rectification multi-segment thermal rectifier
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An Efficient Internet Traffic Classification System Using Deep Learning for IoT 被引量:2
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作者 Muhammad Basit Umair Zeshan Iqbal +3 位作者 Muhammad Bilal Jamel Nebhen Tarik Adnan Almohamad Raja Majid Mehmood 《Computers, Materials & Continua》 SCIE EI 2022年第4期407-422,共16页
Internet of Things(IoT)defines a network of devices connected to the internet and sharing a massive amount of data between each other and a central location.These IoT devices are connected to a network therefore prone... Internet of Things(IoT)defines a network of devices connected to the internet and sharing a massive amount of data between each other and a central location.These IoT devices are connected to a network therefore prone to attacks.Various management tasks and network operations such as security,intrusion detection,Quality-of-Service provisioning,performance monitoring,resource provisioning,and traffic engineering require traffic classification.Due to the ineffectiveness of traditional classification schemes,such as port-based and payload-based methods,researchers proposed machine learning-based traffic classification systems based on shallow neural networks.Furthermore,machine learning-based models incline to misclassify internet traffic due to improper feature selection.In this research,an efficient multilayer deep learning based classification system is presented to overcome these challenges that can classify internet traffic.To examine the performance of the proposed technique,Moore-dataset is used for training the classifier.The proposed scheme takes the pre-processed data and extracts the flow features using a deep neural network(DNN).In particular,the maximum entropy classifier is used to classify the internet traffic.The experimental results show that the proposed hybrid deep learning algorithm is effective and achieved high accuracy for internet traffic classification,i.e.,99.23%.Furthermore,the proposed algorithm achieved the highest accuracy compared to the support vector machine(SVM)based classification technique and k-nearest neighbours(KNNs)based classification technique. 展开更多
关键词 Deep learning internet traffic classification network traffic management QoS aware application classification
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Unusual thermal properties of graphene origami crease:A molecular dynamics study 被引量:2
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作者 Ning Wei Yang Chen +5 位作者 Kun Cai Yingyan Zhang Qingxiang Pei Jin-Cheng Zheng Yiu-Wing Mai Junhua Zhao 《Green Energy & Environment》 SCIE EI CSCD 2022年第1期86-94,共9页
Graphene is a two-dimensional material that can be folded into diverse and yet interesting nanostructures like macro-scale paper origami.Folding of graphene not only makes different morphological configurations but al... Graphene is a two-dimensional material that can be folded into diverse and yet interesting nanostructures like macro-scale paper origami.Folding of graphene not only makes different morphological configurations but also modifies their mechanical and thermal properties.Inspired by paper origami,herein we studied systemically the effects of creases,where sp^(2)to sp^(3)bond transformation occurs,on the thermal properties of graphene origami using molecular dynamics(MD)simulations.Our MD simulation results show that tensile strain reduces(not increases)the interfacial thermal resistance owing to the presence of the crease.This unusual phenomenon is explained by the micro-heat flux migration and stress distribution.Our findings on the graphene origami enable the design of the next-generation thermal management devices and flexible electronics with tuneable properties. 展开更多
关键词 GRAPHENE ORIGAMI Bond transformation Interfacial thermal resistance Molecular dynamics
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Electronic and thermal properties of Ag-doped single crystal zinc oxide via laser-induced technique 被引量:1
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作者 邢欢 王惠琼 +5 位作者 宋廷鲁 李纯莉 戴扬 傅耿明 康俊勇 郑金成 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期44-51,共8页
The doping of ZnO has attracted lots of attention because it is an important way to tune the properties of ZnO.Postdoping after growth is one of the efficient strategies.Here,we report a unique approach to successfull... The doping of ZnO has attracted lots of attention because it is an important way to tune the properties of ZnO.Postdoping after growth is one of the efficient strategies.Here,we report a unique approach to successfully dope the single crystalline ZnO with Ag by the laser-induced method,which can effectively further post-treat grown samples.Magnetron sputtering was used to coat the Ag film with a thickness of about 50 nm on the single crystalline ZnO.Neodymium-doped yttrium aluminum garnet(Nd:YAG)laser was chosen to irradiate the Ag-capped ZnO samples,followed by annealing at700℃for two hours to form ZnO:Ag.The three-dimensional(3D)information of the elemental distribution of Ag in ZnO was obtained through time-of-flight secondary ion mass spectrometry(TOF-SIMS).TOF-SIMS and core-level x-ray photoelectron spectroscopy(XPS)demonstrated that the Ag impurities could be effectively doped into single crystalline ZnO samples as deep as several hundred nanometers.Obvious broadening of core level XPS profiles of Ag from the surface to depths of hundred nms was observed,indicating the variance of chemical state changes in laser-induced Ag-doped ZnO.Interesting features of electronic mixing states were detected in the valence band XPS of ZnO:Ag,suggesting the strong coupling or interaction of Ag and ZnO in the sample rather than their simple mixture.The Ag-doped ZnO also showed a narrower bandgap and a decrease in thermal diffusion coefficient compared to the pure ZnO,which would be beneficial to thermoelectric performance. 展开更多
关键词 zinc oxide Ag-doping laser-induced technique XPS SIMS thermal diffusivity
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Geographical inhomogeneity and temporal variability of mixing property and driving mechanism in the Arctic Ocean 被引量:1
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作者 Jia YOU Zhenhua XU +2 位作者 Robin ROBERTSON Qun LI Baoshu YIN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第3期846-869,共24页
Upper ocean mixing plays a key role in the atmosphere-ocean heat transfer and sea ice extent and thickness via modulating the upper ocean temperatures in the Arctic Ocean.Observations of diffusivities in the Arctic th... Upper ocean mixing plays a key role in the atmosphere-ocean heat transfer and sea ice extent and thickness via modulating the upper ocean temperatures in the Arctic Ocean.Observations of diffusivities in the Arctic that directly indicate the ocean mixing properties are sparse.Therefore,the spatiotemporal pattern and magnitude of diapycnal diffusivities and kinetic energy dissipation rates in the upper Arctic Ocean are important for atmosphere-ocean heat transfers and sea ice changes.These were first estimated from the Ice-Tethered Profilers dataset(2005–2019)using a strain-based fine-scale parameterization.The resultant mixing properties showed signifi cant geographical inhomogeneity and temporal variability.Diapycnal diff usivities and dissipation rates in the Atlantic sector of the Arctic Ocean were stronger than those on the Pacific side.Mixing in the Atlantic sector increased significantly during the observation period;whereas in the Pacific sector,it weakened before 2011 and then strengthened.Potential impact factors include wind,sea ice,near inertial waves,and stratifi cation,while their relative contributions vary between the two sectors of the Arctic Ocean.In the Atlantic sector,turbulent mixing dominated,while in the Pacific sector,turbulent mixing was inhibited by strong stratification prior to 2011,and is able to overcome the stratifi cation gradually after 2014.The vertical turbulent heat fl ux constantly increased in the Atlantic sector year by year,while it decreased in the Pacific sector post 2010.The estimated heat flux variability induced by enhanced turbulent mixing is expected to continue to diminish sea ice in the near future. 展开更多
关键词 MIXING the Arctic Ocean near-inertial waves STRATIFICATION heat flux
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Functionalized graphene oxide-reinforced electrospun carbon nanofibers as ultrathin supercapacitor electrode 被引量:2
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作者 W.K.Chee H.N.Lim +6 位作者 Y.Andou Z.Zainal A.A.B.Hamra I.Harrison M.Altarawneh Z.T.Jiang N.M.Huang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2017年第4期790-798,共9页
Graphene oxide has been used widely as a starting precursor for applications that cater to the needs of tunable graphene. However, the hydrophilic characteristic limits their application, especially in a hydrophobic c... Graphene oxide has been used widely as a starting precursor for applications that cater to the needs of tunable graphene. However, the hydrophilic characteristic limits their application, especially in a hydrophobic condition. Herein, a novel non-covalent surface modification approach towards graphene oxide was conducted via a UV-induced photo-polymerization technique that involves two major routes; a UV-sensitive initiator embedded via pi-pi interactions on the graphene planar rings, and the polymerization of hydrophobic polymeric chains along the surface. The functionalized graphene oxide successfully achieved the desired hydrophobicity as it displayed the characteristic of being readily dissolved in organic solvent. Upon its addition into a polymeric solution and subjected to an electrospinning process,non-woven random nanofibers embedded with graphene oxide sheets were obtained. The prepared polymeric nanofibers were subjected to two-step thermal treatments that eventually converted the polymeric chains into a carbon-rich conductive structure. A unique morphology was observed upon the addition of the functionalized graphene oxide, whereby the sheets were embedded and intercalated within the carbon nanofibers and formed a continuous structure. This reinforcement effectively enhanced the electrochemical performance of the carbon nanofibers by recording a specific capacitance of up to 140.10 F/g at the current density of 1 A/g, which was approximately three folds more than that of pristine nanofibers.It also retained the capacitance up to 96.2% after 1000 vigorous charge/discharge cycles. This functionalization technique opens up a new pathway in tuning the solubility nature of graphene oxide towards the synthesis of a graphene oxide-reinforced polymeric structure. 展开更多
关键词 Non-covalent functionalization Functionalized graphene oxide Electrospinning Carbon nanofiber Supercapacitor electrode
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Influence of nitrogen and magnesium doping on the properties of ZnO films 被引量:1
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作者 李东华 王惠琼 +10 位作者 周华 李亚平 黄政 郑金成 王嘉鸥 钱海杰 奎热西 陈晓航 詹华瀚 周颖慧 康俊勇 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第7期331-335,共5页
Undoped ZnO and doped ZnO films were deposited on the MgO(111) substrates using oxygen plasma-assisted molecular beam expitaxy. The orientations of the grown ZnO thin film were investigated by in situ reflection hig... Undoped ZnO and doped ZnO films were deposited on the MgO(111) substrates using oxygen plasma-assisted molecular beam expitaxy. The orientations of the grown ZnO thin film were investigated by in situ reflection high-energy electron diffraction and ex situ x-ray diffraction(XRD). The film roughness was measured by atomic force microscopy, which was correlated with the grain sizes determined by XRD. Synchrotron-based x-ray absorption spectroscopy was performed to study the doping effect on the electronic properties of the ZnO films, compared with density functional theory calculations.It is found that, nitrogen doping would hinder the growth of thin film, and generate the NOdefect, while magnesium doping promotes the quality of nitrogen-doped ZnO films, inhibiting(N_2)Oproduction and increasing nitrogen content. 展开更多
关键词 ZnO nitrogen magnesium x-ray absorption spectra
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Interleukin-33 exerts pleiotropic immunoregulatory effects in response to Plasmodium berghei ANKA(PbA)infection in mice 被引量:1
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作者 Mohammad Faruq Abd Rachman Isnadi Rusliza Basir +7 位作者 Ramatu Bello Omenesa Roslaini Abd Majid Maizaton Atmadini Abdullah Che Norma Mat Taib Sivan Padma Priya Yong Yean Kong Chin Voon Kin Gambo Lawal Mukhtar 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2023年第12期521-531,I0004,I0005,共13页
Objective:To determine the involvement and the modulatory effects of IL-33 during Plasmodium berghei ANKA(PbA)infection.Methods:PbA infection in male ICR mice was utilized as a model of malaria.Systemically circulatin... Objective:To determine the involvement and the modulatory effects of IL-33 during Plasmodium berghei ANKA(PbA)infection.Methods:PbA infection in male ICR mice was utilized as a model of malaria.Systemically circulating IL-33 levels were determined in blood plasma by enzyme-linked immunosorbent assay(ELISA).After 24 hours post-inoculation of PbA,recombinant IL-33 and ST2,and antibodies against IL-33 and IgG treatments were administered daily for 3 days.Tissue expression and localization of IL-33 were assessed in organs generally affected by malaria via immunohistochemistry.Moreover,histopathological examination was performed to assess the effects of the treatments.Results:The levels of systemic IL-33 were elevated at the critical phase of PbA infection.Likewise,immunohistochemical analysis revealed a significant upregulation of IL-33 expression at the critical phase in the brain,lungs,and spleen of PbA-infected mice as compared to healthy controls.Treatment with IL-33 protected against experimental cerebral malaria development and reduced pathological features in the brain and lungs of the PbA-infected mice.Conclusions:A potential critical role and involvement of IL-33 in PbA infection may hint at the resolution of immunopathological sequelae associated with malaria. 展开更多
关键词 Plasmodium berghei ANKA Malaria IL-33 IMMUNOLOGY Immunotherapy
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Long range electromagnetic field nature of nerve signal propagation in myelinated axons
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作者 Qing-Wei Zhai Kelvin J A Ooi +1 位作者 Sheng-Yong Xu C K Ong 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期619-623,共5页
The nature of saltatory conduction in myelinated axon described by equivalent circuit and circuit theory is still contentious. Recent experimental observations of action potentials transmitting through disjointed nerv... The nature of saltatory conduction in myelinated axon described by equivalent circuit and circuit theory is still contentious. Recent experimental observations of action potentials transmitting through disjointed nerve fibers strongly suggest an electromagnetic wave propagation mechanism of the nerve signals. In this paper, we employ the electromagnetic wave model of the myelinated axon to describe action potential signal propagation. We use the experimental frequency-dependent conductivity and permittivity values of the nerve tissues in order to reliably calculate the electromagnetic modes by using electromagnetic mode solvers. We find that the electromagnetic waves above 10 kHz can be well confined in extracellular fluid–myelin sheath–intracellular fluid waveguide and propagate a distance of 7 mm without much attenuation. Our study may serve as one of the fundamental researches for the better understanding of the nervous system. 展开更多
关键词 action potential propagation and axons neuronal wave propagation NEUROSCIENCE electrodynamics in the nervous system
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