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Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： Y.H.Zhang H.Li Z.W.Yang X.Liu Q.f.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of High-Performance Precision forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

Evasive attacks against autoencoder-based cyberattack detection systems in power systems

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Energy and AI

Energy and AI 2024年第3期17卷 126-135页

作者： Yew Meng Khaw Amir Abiri Jahromi Mohammadreza f.M.Arani Deepa Kundur Department of Electrical and Computer Engineering University of TorontoTorontoON M5S 3G4Canada School of Electronic and Electrical Engineering University of LeedsLeedsLS29JTUnited Kingdom Department of Electrical Computer&Biomedical EngineeringToronto Metropolitan University(formerly Ryerson University)TorontoON M5B 2K3Canada

The digital transformation process of power systems towards smart grids is resulting in improved reliability, efficiency and situational awareness at the expense of increased cybersecurity vulnerabilities. Given the availability of large volumes of smart grid data, machine learning-based methods are considered an effective way to improve cybersecurity posture. Despite the unquestionable merits of machine learning approaches for cybersecurity enhancement, they represent a component of the cyberattack surface that is vulnerable, in particular, to adversarial attacks. In this paper, we examine the robustness of autoencoder-based cyberattack detection systems in smart grids to adversarial attacks. A novel iterative-based method is first proposed to craft adversarial attack samples. Then, it is demonstrated that an attacker with white-box access to the autoencoder-based cyberattack detection systems can successfully craft evasive samples using the proposed method. The results indicate that naive initial adversarial seeds cannot be employed to craft successful adversarial attacks shedding insight on the complexity of designing adversarial attacks against autoencoder-based cyberattack detection systems in smart grids.

关键词： Cybersecurity Adversarial attacks Anomaly detection Iterative-based methods Substati on automati on

Estimation of monthly global solar radiation over twelve major cities of Libya

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Energy and Built Environment 2024年第1期5卷 46-57页

作者： Alhassan Ali Teyabeen Najeya B.Elhatmi Akram A.Essnid f.Mohamed Libyan Center for Solar Energy Research and Studies TripoliLibya Libyan Authority of Scientific Research TripoliLibya

This study aims to estimate monthly averaged daily horizontal global solar *** climatological data collected at twelve major cities located across Libya’s map were used to establish 7 different empirical *** empirical coefficients of the models were calculated using the least square *** accuracy of the models was evaluated using different statistical criteria such as Taylor diagram,mean absolute percentage error,MAPE,and root mean square error,*** results indicated that the sunshine duration-based models are more accurate than air temperature-based models,and the best performance was obtained by the quadratic regression model for all twelve Libyan ***,this regression model can be used for the prediction of monthly mean horizontal global solar radiation at a specific site across Libya’s regions with minimum ***,the results of the global solar irradiance produced by this method can be used for designing solar systems applications.

关键词： Monthly global solar radiation Clearness index Empirical models Performance evaluation Taylor diagram Libya

The asymptotic behavior for a binary alloy in energy and material science:The unified method and its applications

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Journal of Ocean Engineering and Science 2024年第4期9卷 373-378页

作者： M.Adel K.Aldwoah f.Alahmadi M.S.Osman Department of Mathematics Faculty of ScienceIslamic University of MadinahMedinaSaudi Arabia Department of Mathematics Faculty of ScienceCairo UniversityGiza 12613Egypt

The Cahn-Hilliard system was proposed to the first time by Chan and Hilliard in *** model(or system of equations)has intrinsic participation energy and materials sciences and depicts significant characteristics of two phase systems relating to the procedures of phase separation when the temperature is *** instance,it can be noticed when a binary alloy(“Aluminum+Zinc”or“Iron+Chromium”)is cooled down *** this case,partially or totally nucleation(nucleation means the appearance of nuclides in the material)is observed:the homogeneous material in the initial state gradually turns into inhomogeneous,giving rise to a very accurate dispersive ***,when the time scale is slower the microstructure becomes *** this work,to the first time,the unified method is presented to investigate some physical interpretations for the solutions of the Cahn-Hilliard system when its coefficients varying with time,and to show how phase separation of one or two components and their concentrations occurs dynamically in the ***,2D and 3D plots are introduced to add more comprehensive study which help to understand the physical phenomena of this *** technique applied in this analysis is powerful and efficient,as evidenced by the computational work and *** technique can also solve a large number of higher-order evolution equations.

关键词： Cahn-Hilliard system Traveling wave solutions The unified method Variable coefficients

RPLP0/TBP are the most stable reference genes for human dental pulp stem cells under osteogenic differentiation

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World Journal of Stem Cells 2024年第6期16卷 656-669页

作者： Daniel B ferreira Leticia M Gasparoni Cristiane f Bronzeri Katiucia B S Paiva Laboratory of Extracellular Matrix Biology and Cellular Interaction Department of AnatomyInstitute of Biomedical SciencesUniversity of São PauloSão Paulo 05508-000São PauloBrazil

BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data ***,in an unreliable way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitable for such experimental conditions or the reason for choosing such ***,such studies use only one gene when Minimum Information for Publication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more *** impacts the credibility of these studies and causes dis-tortions in the gene expression *** tissue engineering,the accuracy of gene expression drives the best experimental or therapeutical *** cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,both for 35 *** evaluated the gene expression of 10 candidates for RGs[ribosomal protein,large,P0(RPLP0),TATA-binding protein(TBP),GAPDH,actin beta(ACTB),tubulin(TUB),aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(Ef1a),succinate dehydrogenase complex,subunit A,flavoprotein(SDHA),and beta-2-micro-globulin(B2M)]every 7 d(1,7,14,21,28,and 35 d)by *** data were analysed by the four main algorithms,ΔCt method,geNorm,Normfinder,and BestKeeper and ranked by the Reffinder *** subdivided the samples into eight *** All of the data sets from clonogenic and osteogenic samples were analysed using the Reffinder *** final ranking showed RPLP0/TBP as the two most stable RGs and TUB/B2M as the two least stable *** theΔCt method or Normfinder analysis showed TBP/RPLP0 as the two most stable ***,geNorm analysis showed RPLP0/Ef1αin the first *** algorithms’two least stab

关键词： Dental pulp stem cells Reference gene Housekeeping gene Endogenous gene Osteogenic differentiation Reffinder

MicroRNAs in hepatocellular carcinoma treatment:Charting the path forward

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World Journal of Gastroenterology 2024年第11期30卷 1470-1474页

作者： Hong T Lin Antonio f Alvarez Castaneda Somashekar G Krishna Khalid Mumtaz Division of Gastroenterology Hepatology and NutritionDepartment of MedicineThe Ohio State University Wexner Medical CenterColumbusOH 43210United States

MicroRNAs(miRNAs)are recognized for their involvement in the regulation of gene expression and exhibit significant potential in both the prognostic assessment and treatment of hepatocellular carcinoma(HCC).HCC,like other tumors,seldom occurs in isolation;instead,it evolves within a microenvironment featuring oncogenic and tumor-suppressive *** combined with suitable delivery vehicles,miRNA technology provides the capability to directly engage with these elements,thereby hindering tumor formation and *** research in this domain holds the promise of enabling a more efficacious and multi-modal treatment approach for HCC in the near future.

关键词： Hepatocellular carcinoma Tumor microenvironment MicroRNA Mesenchymal stem cell Exosome

Localized-states quantum confinement induced by roughness in CdMnTe/CdTe heterostructures grown on Si(111) substrates

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Journal of Semiconductors 2024年第9期45卷 28-35页

作者： Leonarde N.Rodrigues Wesley f.Inoch Marcos L.f.Gomes Odilon D.D.Couto Jr. Bráulio S.Archanjo Sukarno O.ferreira Physics Department Federal University of ViçosaViçosa36570-900Minas GeraisBrazil Instituto de física Gleb Wataghin Universidade Estadual de CampinasCampinas13083-859São PauloBrazil National Institute of Metrology Quality and Technology(Inmetro) Materials Metrology Division(DIMAT)Xerém2525-020Rio de JaneiroBrazil

This work shows that despite a lattice mismatch of almost 20%, CdMnTe/CdTe/CdMnTe heterostructures grown directly on Si(111) have surprisingly good optical emission properties. The investigated structures were grown by molecular beam epitaxy and characterized by scanning transmission electron microscopy, macro-and micro-photoluminescence. Low temperature macro-photoluminescence experiments indicate three emission bands which depend on the CdTe layer thickness and have different confinement characteristics. Temperature measurements reveal that the lower energy emission band (at 1.48 eV)is associated to defects and bound exciton states, while the main emission at 1.61 eV has a weak 2D character and the higher energy one at 1.71 eV has a well-defined (zero-dimensional, 0D) 0D nature. Micro-photoluminescence measurements show the existence of sharp and strongly circularly polarized (up to 40%) emission lines which can be related to the presence of Mn in the heterostructure. This result opens the possibility of producing photon sources with the typical spin control of the diluted magnetic semiconductors using the low-cost silicon technology.

关键词： CdMnTe/CdTe/CdMnTe heterostructure CdTe/CdMnTe quantum emitters quantum dot-like emission silicon(111)substrate

Modelling dynamic pantograph loads with combined numerical analysis

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Railway Engineering Science 2024年第1期32卷 81-94页

作者： f.f.Jackson R.Mishra J.M.Rebelo J.Santos P.Antunes J.Pombo H.Magalhaes L.Wills M.Askill School of Computing and Engineering University of HuddersfieldHuddersfieldUK School of Computing and Engineering Institute of Railway ResearchUniversity of HuddersfieldHuddersfieldUK IDMEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal ISEL Instituto Politecnico de LisboaLisbonPortugal Hitachi Rail Newton AycliffeUK Wabtec/Brecknell Willis ChardUK

Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric *** heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile,and thus aerodynamic load changes significantly with operational *** research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations,such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact ***,computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting,such as that of the recessed cavity on a Class 800 *** an aerodynamic perspective,this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing,although the difference between the two is found to reduce with increasing pantograph *** the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph *** results obtained show how considering aerodynamic forces enhance the realism of the models,leading to behaviour of the pantograph-catenary contact forces closely matching that seen in experimental tests.

关键词： Pantograph-catenary interaction Pantograph aerodynamics Computational fluid dynamics Pantograph loads Current collection performance

Specific *** valorem taxation and social welfare in mixed duopoly with foreign ownership

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Economic and Political Studies 2024年第2期12卷 207-219页

作者： Ming Sun Leonard f.S.Wang Qidi Zhang School of Economics and Management Chang’an UniversityXi’anChina Wenlan School of Business Zhongnan University of Economics and LawWuhanChina

In this paper,we set up a mixed duopoly competition model between state-owned and private firms in order to compare specific and ad valorem *** that the total output under specific and ad valorem taxation remains unchanged,we find that if the public firm is completely privatised,the output of the private firm under the two tax schemes will be the *** the public firm is not completely privatised,the output of the the private firm under specific taxation will be greater than that under ad valorem *** the private firm is a pure local one,the social benefits will be the same under the two tax ***,if the private firm is a joint venture that involves domestic and foreign entities,social welfare under ad valorem taxation will be greater than that under specific taxation.

关键词： Specific taxation ad valorem taxation mixed duopoly imperfect competition privatisation foreign ownership