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Nano Research 2021年第5期14卷 1450-1456页

作者： Petra S.Pálvölgyi Daniel Sebők Imre Szenti Eva Bozo Henri Ervasti Olli Pitkänen Jari Hannu Heli Jantunen Marko E.Leinonen sami myllymäki Akos Kukovecz Krisztian Kordas Microelectronics Research Unit Faculty of Information and Electrical EngineeringUniversity of OuluP.O.Box 4500FI-90570OuluFinland Interdisciplinary Excellence Centre Department of Applied and Environmental ChemistryUniversity of SzegedRerrich Béla tér 1H-6720SzegedHungary Centre for Wireless Communications University of OuluP.O.Box 4500FI-90570OuluFinland

In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm3), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10−4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band.

关键词： low-permittivity materials low-loss dielectrics templated sol-gel synthesis silica foams 6G telecommunication

DeBERTa-GRU: Sentiment Analysis for Large Language Model

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Computers, Materials & Continua 2024年第6期79卷 4219-4236页

作者： Adel Assiri Abdu Gumaei Faisal Mehmood Touqeer Abbas sami Ullah Department of Informatics for Business College of BusinessKing Khalid UniversityAbha61421Saudi Arabia Department of Computer Science College of Computer Engineering and SciencesPrince Sattam bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia School of Electrical and Information Engineering Zhengzhou UniversityZhengzhou450001China Department of Computer Science and Technology Beijing University of Chemical TechnologyBeijing100029China Department of Computer Science Government College University FaisalabadFaisalabadPunjab38000Pakistan

Modern technological advancements have made social media an essential component of daily *** media allow individuals to share thoughts,emotions,and *** analysis plays the function of evaluating whether the sentiment of the text is positive,negative,neutral,or any other personal emotion to understand the sentiment context of the *** analysis is essential in business and society because it impacts strategic *** analysis involves challenges due to lexical variation,an unlabeled dataset,and text distance *** execution time increases due to the sequential processing of the sequence ***,the calculation times for the Transformer models are reduced because of the parallel *** study uses a hybrid deep learning strategy to combine the strengths of the Transformer and Sequence models while ignoring their *** particular,the proposed model integrates the Decoding-enhanced with Bidirectional Encoder Representations from Transformers(BERT)attention(DeBERTa)and the Gated Recurrent Unit(GRU)for sentiment *** the Decoding-enhanced BERT technique,the words are mapped into a compact,semantic word embedding space,and the Gated Recurrent Unit model can capture the distance contextual semantics *** proposed hybrid model achieves F1-scores of 97%on the Twitter Large Language Model(LLM)dataset,which is much higher than the performance of new techniques.

关键词： DeBERTa GRU Naive Bayes LSTM sentiment analysis large language model

Insight into the dynamics of non-Newtonian Carreau fluid when viscous dissipation,entropy generation,convective heating and diffusion are significant

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 34-46页

作者： ZHOU Shuang-shuang Muhammad Ijaz Khan sami Ullah Khan Sumaira Qayyum School of Science Hunan City UniversityYiyang 413000China Department of Mechanical Engineering Prince Mohammad Bin Fahd UniversityP.O.Box1664Al-Khobar 31952Kingdom of Saudi Arabia Department of Mathematics Namal UniversityMianwali 42250Pakistan Department of Mathematics Quaid-I-Azam University 45320Islamabad 44000Pakistan

The investigation endorsed the convective flow of Carreau nanofluid over a stretched surface in presence of entropy generation *** novel dynamic of viscous dissipation is utilized to analyze the thermal mechanism of magnetized *** convective boundary assumptions are directed in order to examine the heat and mass transportation of *** thermal concept of thermophoresis and Brownian movements has been re-called with the help of Buongiorno *** problem formulated in dimensionless form is solved by NDSolve *** graphical analysis for parameters governed by the problem is performed with physical *** affiliation of entropy generation and Bejan number for different parameters is inspected in *** numerical data for illustrating skin friction,heat and mass transfer rate is also *** motion of the fluid is highest for the viscosity ratio *** temperature of the fluid rises via thermal Biot *** generation rises for greater Brinkman number and diffusion parameter.

关键词： heat generation surface reaction CNTs based nano uid stretching/shrinking sheet thermal radiation

Towards Blockchain-Based Secure BGP Routing,Challenges and Future Research Directions

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Computers, Materials & Continua 2024年第5期79卷 2035-2062页

作者： Qiong Yang Li Ma Shanshan Tu sami Ullah MuhammadWaqas Hisham Alasmary Faculty of Information Technology Beijing University of TechnologyBeijing100124China School of Information Science and Technology North China University of TechnologyBeijing100144China Department of Computer Science Shaheed Benazir Bhutto UniversitySheringal18050Pakistan School of Computing and Mathematical Science Faculty of Engineering and ScienceUniversity of GreenwichLondonSE109LSUK School of Engineering Edith Cowan UniversityPerth6027Australia Department of Computer Science King Khalid UniversityAbha61421Saudi Arabia

Border Gateway Protocol(BGP)is a standard inter-domain routing protocol for the Internet that conveys network layer reachability information and establishes routes to different *** BGP protocol exhibits security design defects,such as an unconditional trust mechanism and the default acceptance of BGP route announcements from peers by BGP neighboring nodes,easily triggering prefix hijacking,path forgery,route leakage,and other BGP security ***,the traditional BGP security mechanism,relying on a public key infrastructure,faces issues like a single point of failure and a single point of *** decentralization,anti-tampering,and traceability advantages of blockchain offer new solution ideas for constructing secure and trusted inter-domain routing *** this paper,we summarize the characteristics of BGP protocol in detail,sort out the BGP security threats and their ***,we analyze the shortcomings of the traditional BGP security mechanism and comprehensively evaluate existing blockchain-based solutions to address the above problems and validate the reliability and effectiveness of blockchain-based BGP security methods in mitigating BGP security ***,we discuss the challenges posed by BGP security problems and outline prospects for future research.

关键词： BGP security blockchain prefix hijacking trust model secure routing

The Impact of Network Topologies and Radio Duty Cycle Mechanisms on the RPL Routing Protocol Power Consumption

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Computers, Materials & Continua 2024年第5期79卷 1835-1854页

作者： Amal Hkiri Hamzah Faraj Omar Ben Bahri Mouna Karmani sami Alqurashi Mohsen Machhout Physic Department Electronics and Micro-Electronics LaboratoryFaculty of Sciences of MonastirMonastir5000Tunisia Department of Science and Technology College of RanyahTaif UniversityP.O.Box 11099Taif21944Saudi Arabia

The Internet of Things(IoT)has witnessed a significant surge in adoption,particularly through the utilization of Wireless Sensor Networks(WSNs),which comprise small internet-connected *** deployments span various environments and offer a multitude of ***,the widespread use of battery-powered devices introduces challenges due to their limited hardware resources and communication *** response to this,the Internet Engineering Task Force(IETF)has developed the IPv6 Routing Protocol for Low-power and Lossy Networks(RPL)to address the unique requirements of such *** the critical role of RPL in maintaining high performance,this paper proposes a novel approach to optimizing power ***,it introduces a developed sensor motes topology integrated with a Radio Duty Cycling(RDC)mechanism aimed at minimizing power *** rigorous analysis,the paper evaluates the power efficiency of this approach through several simulations conducted across different network topologies,including random,linear,tree,and elliptical ***,three distinct RDC mechanisms—CXMAC,ContikiMAC,and NullRDC—are investigated to assess their impact on power *** findings of the study,based on a comprehensive and deep analysis of the simulated results,highlight the efficiency of ContikiMAC in power *** research contributes valuable insights into enhancing the energy efficiency of RPL-based IoT networks,ultimately facilitating their widespread deployment and usability in diverse environments.

关键词： WSN IoT radio duty cycles topologies

Enhancement of mechanical and tribological performance of Ti-6Al-4V alloy by laser surface alloying with Inconel 625 and SiC precursor materials

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Friction 2024年第9期12卷 2089-2107页

作者： Hao-Ran CHENG ki-Hoon SHIN Hong Seok kiM Department of Mechanical Engineering Graduate School of Seoul National University of Science and TechnologySeoul 01811Republic of Korea Department of Mechanical and Automotive Engineering Seoul National University of Science and TechnologySeoul 01811Republic of Korea

This study focused on producing metal matrix composite(MMC)coatings on Ti–6Al–4V alloy through laser surface alloying using a novel combination of Inconel 625 and SiC precursor *** ratios of alloying powders were examined to evaluate surface properties such as microhardness,wear resistance,and friction coefficient,along with analyzing the phase composition and microstructure of the *** in situ synthesized MMC coatings exhibited the presence ofα-Ti,NiTi,NiTi_(2),and TiC ***,Ti_(5)Si_(3)andα-Ti/Ti_(5)Si_(3)eutectic structures were observed when the SiC content exceeded 20%.In comparison to the titanium substrate,the MMC coating significantly enhanced microhardness by over threefold and reduced wear by 95%.However,it was crucial to carefully select the appropriate combination of alloying powders to avoid a substantial decrease in friction performance and excessive formation of *** a comparative analysis of experimental results,the optimal precursor material composition was identified as 85%Inconel 625 and 15%*** study demonstrated the effective utilization of Inconel 625 and SiC alloying materials to enhance the surface properties of titanium alloys,thereby expanding their application in challenging environments.

关键词： titanium alloy Inconel 625 SiC ceramic laser surface alloying metal matrix composite(MMC)

Enhancing Energy Efficiency with a Dynamic Trust Measurement Scheme in Power Distribution Network

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Computers, Materials & Continua 2024年第3期78卷 3909-3927页

作者： Yilei Wang Xin Sun Guiping Zheng Ahmar Rashid sami Ullah Hisham Alasmary Muhammad Waqas Zhejiang Electric-Power Corporation Research Institute Zhejiang310014China Faculty of Information Technology Beijing University of TechnologyBeijing100124China Beijing Trusty Cloud Technology Co. Ltd.Beijing100022China Department of Computer Science and Engineering Ghulam Ishaq Khan Institute of Engineering Sciences and EngineeringTopi23640Pakistan Department of Computer Science Shaheed Benazir Bhutto UniversitySheringalUpper Dir18050Pakistan Department of Computer Science College of Computer ScienceKing Khalid UniversityAbha61421Saudi Arabia School of Computing and Mathematical Science Faculty of Engineering and ScienceUniversity of GreenwichLondonSE109LSUK School of Engineering Edith Cowan UniversityPerth6027Australia

The application of Intelligent Internet of Things(IIoT)in constructing distribution station areas strongly supports platform transformation,upgrade,and intelligent *** sensing layer of IIoT comprises the edge convergence layer and the end sensing layer,with the former using intelligent fusion terminals for real-time data collection and ***,the influx of multiple low-voltage in the smart grid raises higher demands for the performance,energy efficiency,and response speed of the substation fusion ***,it brings significant security risks to the entire distribution substation,posing a major challenge to the smart *** response to these challenges,a proposed dynamic and energy-efficient trust measurement scheme for smart grids aims to address these *** scheme begins by establishing a hierarchical trust measurement model,elucidating the trust relationships among smart IoT *** then incorporates multidimensional measurement factors,encompassing static environmental factors,dynamic behaviors,and energy *** comprehensive approach reduces the impact of subjective factors on trust ***,the scheme incorporates a detection process designed for identifying malicious low-voltage end sensing units,ensuring the prompt identification and elimination of any malicious ***,in turn,enhances the security and reliability of the smart grid *** effectiveness of the proposed scheme in pinpointing malicious nodes has been demonstrated through simulation ***,the scheme outperforms established trust metric models in terms of energy efficiency,showcasing its significant contribution to the field.

关键词： IIoT trusted measure energy efficient

Regional economic assessment of a novel place-based model for sustainable food systems

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Geography and Sustainability 2024年第2期5卷 220-229页

作者： Susanna Kujala Kari Koppelmäki University of Helsinki Ruralia InstituteKampusranta 9 C 60320SeinäjokiFinland University of Helsinki Ruralia InstituteLönnrotinkatu 750100MikkeliFinland Wageningen University&Research Farming Systems Ecology GroupDroevendaalsesteeg 16708PBWageningenThe Netherlands

Several actions from both the environmental and human viewpoints have already been made to meet the sustainability goals targeted at food ***,new place-based ideas to improve sustainability are *** symbiosis(AES),a novel food system model,is an example of a suggested system-level change to attain sustainability targets;it is a symbiosis of food production and processing using renewable energy that uses its own *** has already been found advantageous from the ecological and biophysical viewpoints,but a regional economic evaluation of the model is still ***,the aim of our paper is to assess the regional economic impact of a possible systemic change in the food system using the network of agroecological symbiosis(NAES)as an *** applied scenarios representing different ways of moving towards envisioned NAES models in Mäntsälä,Finland,and a computable general equilibrium model to evaluate the regional economic *** to our results,both regional economy and employment would increase,and the regional production base would diversify with NAES implementation applied to the region,but the extent of the benefits varies between *** scenario that includes change in both public and private food demand,production of bioenergy and utilization of by-products would cause the largest ***,realizing NAES requires investments that may influence the actual implementation of such ***,a change towards NAES can promote an economically and spatially just transition to sustainability,as NAES seems to be economically most beneficial for rural areas.

关键词： Sustainability Regional economy Localized food system Renewable energy Circularity

Modification strategies improving the electrochemical and structural stability of high-Ni cathode materials

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Journal of Energy Chemistry 2024年第9期96卷 185-205页

作者： Yoon Bo Sim Hami Lee Junyoung Mun ki Jae kim Department of Energy Science Sungkyunkwan UniversitySuwon 16419Republic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwon 16419Republic of Korea

With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving ***,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)***,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization *** direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode ***,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk *** this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode *** also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.

关键词： High energy density High-Ni cathode materials Degradation Structural stability Lithium-ion battery

Inclusion of CoTiO_(3) to ameliorate the re/dehydrogenation properties of the Mg–Na–Al system

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Journal of Magnesium and Alloys 2024年第3期12卷 1215-1226页

作者： N.A.Ali N.Y.Yusnizam N.A.Sazelee sami-ullah Rather Haizhen Liu M.Ismail Energy Storage Research Group Faculty of Ocean Engineering TechnologyUniversiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Department of Chemical and Materials Engineering King Abdulaziz UniversityP.O.Box80204Jeddah 21589Saudi Arabia Guangxi Novel Battery Materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures Nanning 530004China

For the first time,the MgH_(2)–NaAlH_(4)(ratio 4:1)destabilized system with CoTiO_(3) addition has been *** CoTiO_(3)-doped MgH_(2)–NaAlH_(4) sample begins to dehydrogenate at 130℃,which is declined by 40℃ compared to the undoped MgH_(2)–NaAlH_(4).Moreover,the de/rehydrogenation kinetics characteristics of the CoTiO_(3)-doped MgH_(2)–NaAlH_(4) were greatly *** the inclusion of CoTiO_(3),the MgH_(2)–NaAlH_(4) composite absorbed 5.2 wt.%H_(2),higher than undoped MgH_(2)–NaAlH_(4).In the context of dehydrogenation,the CoTiO_(3)-doped MgH_(2)–NaAlH_(4) sample desorbed 2.6 wt.%H_(2),almost doubled compared to the amount of hydrogen desorbed from the undoped MgH_(2)–NaAlH_(4) *** activation energy obtained by the kissinger analysis for MgH_(2) decomposition was significantly lower by 35.9 kJ/mol than the undoped MgH_(2)–NaAlH_(4) *** reaction mechanism demonstrated that new phases of MgCo and AlTi_(3) were generated in situ during the heating process and are likely to play a substantial catalytic function and be useful in ameliorating the de/rehydrogenation properties of the destabilized MgH_(2)–NaAlH_(4) system with the inclusion of CoTiO_(3).

关键词： Destabilize system Magnesium hydride Sodium alanate Hydrogen storage Additive.