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Truly optimal semi-active damping to control free vibration of a single degree of freedom system

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Th.oretical & Applied Mech.nics Letters 2024年第2期14卷 142-145页

作者： Viet Duc la Ngoc Tuan Nguyen Institute of Mech.nics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Graduate University of Science and Tech.ology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

Th.s paper studies a single degree of freedom system under free vibration and controlled by a general semiactive damping.A general integral of squared error is considered as th. performance index.A one-time switch.ng damping controller is proposed and *** pontryagin maximum principle is used to prove th.t no oth.r form of semi-active damping can provide th. better performance th.n th. proposed one-time switch.ng damping.

关键词： Analytical optimization Quadratic integral Lyapunov equation Pontryagin maximum principle

A convolutional neural network to detect possible h.dden data in spatial domain images

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Cybersecurity 2024年第1期7卷 37-52页

作者： Jean De la Croix Ntivuguruzwa Toh.ri Ah.ad Department of Informatics Institut Teknologi Sepuluh Nopember(ITS)Kampus ITS Keputih SukoliloSurabaya60111Indonesia African Center of Excellence in th. Internet of Th.ngs College of Science and TechnologyUniversity of Rwanda3900KigaliRwanda

h.ding secret data in digital multimedia h.s been essential to protect th. ***,attackers with.a steganalysis tech.ique may break *** steganalysis meth.ds h.ve good results with.conventional Mach.ne Learning(ML)tech.iques;h.wever,th. introduction of Convolutional Neural Network(CNN),a deep learning paradigm,ach.eved better performance over th. previously proposed ML-based *** th. existing CNN-based approach.s yield good results,th.y present performance issues in classification accuracy and stability in th. network training *** research.proposes a new meth.d with.a CNN arch.tecture to improve th. h.dden data detection accuracy and th. training ph.se stability in spatial domain *** proposed meth.d comprises th.ee ph.ses:pre-processing,feature extraction,and ***,in th. pre-processing ph.se,we use spatial rich.model filters to enh.nce th. noise with.n images altered by data h.ding;secondly,in th. feature extraction ph.se,we use two-dimensional depth.ise separable convolutions to improve th. signal-to-noise and regular convolutions to model local features;and finally,in th. classification,we use multi-scale average pooling for local features aggregation and representability enh.ncement regardless of th. input size variation,followed by th.ee fully connected layers to form th. final feature maps th.t we transform into class probabilities using th. softmax *** results identify an improvement in th. accuracy of th. considered recent sch.me ranging between 4.6 and 10.2%with.reduced training time up to 30.81%.

关键词： Information security Spatial domain steganalysis Deep learning Convolutional neural network Infrastructure

ENSO impacts on litter stocks and water h.lding capacity in secondary forests in eastern Amazonia

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Journal of Forestry Research 2024年第1期35卷 83-89页

作者： Julia Isabella de Matos rodrigues Walmer Bruno Roch. Martins Victor Pereira de Oliveira Myriam Suelen da Silva Wanzerley h.lio Brito dos Santos Júnior Francisco de Assis Oliveira Graduate Program in Forestry Sciences Av.Presidente Tancredo Neves2501BelémPará66077-530Brazil Federal Rural University of Amazonia Av.Presidente Tancredo Neves2501BelémPará66077-530Brazil Federal Rural University of Amazonia Tv.Pau-AmareloCapitão PoçoPará68650-000Brazil National Institute of Amazonia Research Av.Constelação Cruzeiro do SulManausAmazonas 69060-062Brazil

Among th. impacts of climate ch.nge,th.re is th. intensification of ph.nomena such.as th. El Niño South.ern Oscillation(ENSO)responsible for El Niño and la Niñ***,understanding th.ir effects on th. functional pro-cesses of forests is ***,th.s study evaluated th. effects of ENSO on litter stock and water h.lding capac-ity(Wh.)in a successional forest in eastern *** occurred in periods with.th. most rainfall in El Niño(2019)and least in la Niña(2021)*** permanent plots were used to sample *** effects were evident for Wh.,h.gh.r during El Niñ***,th.s influence was not clear for litter,as only in th. rainy season effects were *** was a positive correlation of Wh. with.precipitation and h.midity,wh.le litter stocks were negatively correlated with.temperature and wind *** th. subject of th.s study requires long-term assessments,preliminary results suggests th.t,depending on th. intensity of ENSO,forest functional processes can be strongly impacted and *** conclusion reinforces warnings by th. scientific community about th. impacts of climate ch.nge on th. maintenance of litter stocks,decomposition and,consequently,th. biogeoch.mical cycle and essential ecosystem services for th. maintenance of Amazonia *** need to develop long-term research.to understand th. effects of climatic ch.nge on litter stocks and water h.lding capacity is h.gh.igh.ed,especially in Amazonia.

关键词： Seasonality Climate ch.nge Succession ecosystem Biogeoch.mical cycle Amazonia biodiversity

ZnSb/Ti_(3)C_(2)T_(x)MXene van der Waals h.terojunction for flexible near-infrared ph.todetector arrays

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Journal of Semiconductors 2024年第5期45卷 99-105页

作者： Ch.qiao h. Ruiqing Ch.i Zh.ngming Wei la Li Guozh.n Sh.n State Key laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronic Engineering University of Chinese Academy of SciencesBeijing 100049China Sch.ol of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China

Two-dimension(2D)van der Waals h.terojunction h.lds essential promise in ach.eving h.gh.performance flexible near-infrared(NIR)***,we report th. successful fabrication of ZnSb/Ti_(3)C_(2)T_(x)MXene based flexible NIR ph.todetector array via a facile ph.tolith.graph. *** single ZnSb/Ti_(3)C_(2)T_(x)ph.todetector exh.bited a h.gh.ligh.-to-dark current ratio of 4.98,fast response/recovery time(2.5/1.3 s)and excellent stability due to th. tigh. connection between 2D ZnSb nanoplates and 2D Ti_(3)C_(2)T_(x)MXene nanoflakes,and th. formed 2D van der Waals *** polyeth.lene tereph.h.late(PET)substrate enables th. ZnSb/Ti_(3)C_(2)T_(x)ph.todetector with.tand bending such.th.t stable ph.toelectrical properties with.non-obvious ch.nge were maintained over 5000 bending ***,th. ZnSb/Ti_(3)C_(2)T_(x)ph.todetectors were integrated into a 26×5 device array,realizing a NIR image sensing application.

关键词： ZnSb nanoplates Ti_(3)C_(2)T_(x)MXene van der Waals h.terojunction flexible ph.todetector image sensing

h.gh.Seebeck Coefficient Th.rmally Ch.rgeable Supercapacitor with.Synergistic Effect of Multich.nnel Ionogel Electrolyte and Ti3C2Tx MXene-Based Composite Electrode

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 367-377页

作者： Ch.n, Zh.ngming Du, Zh.jian Li, la Jiang, Kai Ch.n, Di Sh.n, Guozh.n Univ Sci & Tech.ol Beijing Sch Math & Phys Beijing 100083 Peoples R China Beijing Inst Tech.ol Sch Integrated Circuits & Elect Beijing 100081 Peoples R China Ch.nese Pla Chinese PLA Gen Hosp Inst Hepatobiliary Surg Chinese PLA Fac Hepatopancreato Biliary Surg Beijing 100853 Peoples R China Ch.nese Pla Key Lab Digital Hepetobiliary Surg Beijing 100853 Peoples R China

Th.rmally ch.rgeable supercapacitors can collect low-grade h.at generated by th. h.man body and convert it into electricity as a power supply unit for wearable electronics. h.wever, th. low Seebeck coefficient and h.at-to-electricity conversion efficiency h.nder furth.r application. In th.s paper, we designed a h.gh.performance th.rmally ch.rgeable supercapacitor device composed of ZnMn2O4@Ti3C2Tx MXene composites (ZMO@Ti3C2Tx MXene) electrode and UIO-66 metal-organic framework doped multich.nnel polyvinylidene fluorideh.xafluoro-propylene ionogel electrolyte, wh.ch.realized th. th.rmoelectric conversion and electrical energy storage at th. same time. Th.s th.rmally ch.rgeable supercapacitor device exh.bited a h.gh.Seebeck coefficient of 55.4 mV K-1, th.rmal voltage of 243 mV, and outstanding h.at-to-electricity conversion efficiency of up to 6.48% at th. temperature difference of 4.4 K. In addition, th.s device sh.wed excellent ch.rge-disch.rge cycling stability at h.gh.temperature differences (3 K) and low-temperature differences (1 K), respectively. Connecting two th.rmally ch.rgeable supercapacitor units in series, th. generated output voltage of 500 mV furth.r confirmed th. stability of devices. Wh.n a single device was worn on th. arm, a th.rmal voltage of 208.3 mV was obtained indicating th. possibility of application in wearable electronics.

关键词： ionogel electrode Soret effect th.rmally ch.rgeable supercapacitor Ti3C2Tx MXene UIO-66 MOF GELS

Th. Influence of Significant Public h.alth.Events on Offline Consumption and Its Path.ays

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Journal of Systems Science and Systems Engineering 2024年第5期33卷 627-648页

作者： Baile Lu Kewei Zh.u Sh.ai h.o la Ta h.ngyan Dai Weih.a Zh.u College of Systems Engineering National University of Defense TechnologyChangsha 410073China Business Sch.ol Central University of Finance and EconomicsBeijing 100081China Department of Marketing and Operations Management College of BusinessSouthern University of Science and TechnologyShenzhen 518055China Sch.ol of Management Zhejiang UniversityHangzhou 310058China

In th. face of a significant public h.alth.event,consumers may eith.r increase th.ir panic buying or decrease th.ir willingness to make *** study focuses on th. impact of a significant public h.alth.event on offline store sales and consumer consumption,utilizing data from ch.in convenience stores in h.fei and Wuh. during early 2019 and early 2020 in *** a difference-in-differences model,th. study investigates th. effect of th. significant public h.alth.event outbreak on weekly store sales,order numbers,and consumer consumption in terms of product quantities,transaction amount,average amount per order,and transaction *** from prior literature th.t finds h.arding beh.vior of consumers online,th. findings of th.s paper indicate a significant reduction in stores’offline weekly sales and order numbers,as well as consumers’offline weekly consumption across th. four dimensions,as a result of th. significant public h.alth.event ***,employing a mediation model,th. study explores th. path.ay of population mobility th.ough.wh.ch.th. significant public h.alth.event adversely affects offline ***,subset analysis is conducted for stores located in different areas and consumers with.varying ch.racteristics,revealing th.t th. aforementioned conclusions predominantly apply to stores situated in office areas and residential areas,as well as consumers with.eith.r no apparent preference for different product categories or a noticeable preference for food.

关键词： Significant public h.alth.event offline consumption population mobility mediating effect

DNA metabarcoding reveals seasonal ch.nges in diet composition across four arth.opod-eating lizard species(Ph.ynosomatidae:Sceloporus)

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Integrative Zoology 2024年第3期19卷 480-495页

作者： Mauricio h.RNÁNDEZ Steph.nie h.REIRA-PACh.CO Antton ALBERDI Aníbal h.DÍAZ DE la VEGA-PÉREZ Arturo ESTRADA-TORRES Sergio ANCONA Yendi E.NAVARRO-NOYA Doctorado en Ciencias Biológicas Centro Tlaxcala de Biología de la ConductaUniversidad Autónoma de TlaxcalaTlaxcalaMexico Estación Científica la Malinch. Centro Tlaxcala de Biología de la ConductaUniversidad Autónoma de TlaxcalaTlaxcalaMexico Center for Evolutionary h.logenomics The Globe InstituteUniversity of CopenhagenCopenhagenDenmark Consejo Nacional de Ciencia y Tecnología-Centro Tlaxcala de Biología de la Conducta Universidad Autónoma de TlaxcalaTlaxcalaMexico Departamento de Ecología Evolutiva Instituto de EcologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico laboratorio de Interacciones Bióticas Centro de Investigación en Ciencias BiológicasUniversidad Autónoma de TlaxcalaSan Felipe IxtacuixtlaTlaxcalaMexico

Diet composition and its ecological drivers are rarely investigated in coexisting closely related *** used a molecular approach.to ch.racterize th. seasonal variation in diet composition in four spiny lizard species inh.biting a mountainous *** metabarcoding revealed th.t th. lizards Sceloporus aeneus,***,***,and *** mostly consumed arth.opods of th. orders h.miptera,Araneae,h.menoptera,and *** terrestrial lizards *** and *** mostly predated ants and spiders,wh.reas th. arboreal–saxicolous *** and saxicolous *** largely consumed grassh.ppers and *** taxonomic and ph.logenetic diversity of th. prey was h.gh.r during th. dry season th.n th. rainy season,likely because reduced prey availability in th. dry season forced lizards to diversify th.ir diets to meet th.ir nutritional *** and ph.logenetic composition varied seasonally depending on th. species,but only dietary composition varied with.*** dietary turnover was greater in *** th.n in ***,suggesting site-specific seasonal variability in prey availability;no oth.r differences among species were ***,wh.ch.lives at th. h.gh.st altitude in our study site,displayed interseasonal variation in diet *** differences were correlated with.th. species’feeding strategies and elevational distribution,wh.ch.likely contributed to th. coexistence of th.se lizard species in th. studied geograph.c area and beyond.

关键词： arth.opod-eating lizards diet breadth environmental barcoding mountainous ecosystem seasonal dietary sh.fts

Polarization Study of Swift J151857.0–572147 with.IXPE Observation

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Research.in Astronomy and Astroph.sics 2024年第9期24卷 60-65页

作者： Yu-Sh.n Ling Fei Xie Ming-Yu Ge Fabio la Monaca Guangxi Key laboratory for Relativistic Astroph.sics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Key laboratory of Particle Astroph.sics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China INAF Istituto di Astrofisica e Planetologia Spaziali Via del Fosso del Cavaliere 10000133 RomaItaly Dipartimento di Fisica Universitàdegli Studi di Roma“Tor Vergata”Via della Ricerca Scientifica 100133 RomaItaly Dipartimento di Fisica Universitàdegli Studi di Roma“La Sapienza”Piazzale Aldo Moro 500185 RomaItaly

We present an analysis of th. Imaging X-ray Polarimetry Explorer observation from a newly discovered transient source:Swift *** obtained polarization degree(PD)and angle are 0.3%±0.3% and -24°±26°respectively in 2-8 keV with.n 68%confidence level errors,and polarization results are below MDP99in all energy bins,with.th. upper limit on PD of 0.8% in th. 2-8 keV energy *** quasi-periodic oscillations(QPOs)are detected in th.s *** polarization and QPO analyses support th. h.poth.sis th.t th. source was in th. h.gh.soft state,and th. results are consistent with.predictions for a th.n accretion disk model.

关键词： stars:black h.les polarization X-rays:bursts

Ch.llenges and pitfalls of youth.onset type 2 diabetes

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World Journal of Diabetes 2024年第5期15卷 876-885页

作者： lavinia la Grasta Sabolic Sanda Marusic Maja Cigrovski Berkovic Department of Pediatric Endocrinology and Diabetology University Hospital Centre Sestre MilosrdniceZagreb 10000Croatia Sch.ol of Medicine Catholic University of CroatiaZagreb 10000Croatia Department for Sport and Exercise Medicine University of Zagreb Faculty of KinesiologyZagreb 10000Croatia

Th. incidence and prevalence of youth.onset type 2 diabetes mellitus(T2DM)are *** rise in frequency and severity of ch.ldh.od obesity,inclination to sedentary lifestyle,and epigenetic risks related to prenatal h.perglycemia exposure are important drivers of th. youth.onset T2DM epidemic and migh. as well be responsible for th. early onset of diabetes ***,youth.onset T2DM h.s a more extreme metabolic ph.notype th.n adult-onset T2DM,with.greater insulin resistance and more rapid deterioration of beta cell ***,intermediate complications such.as microalbuminuria develop in late ch.ldh.od or early adulth.od,wh.le end-stage complications develop in *** to th. lack of efficacy and safety data,several drugs available for th. treatment of adults with.T2DM h.ve not been approved in youth.reducing th. ph.rmacological treatment *** th.s mini review,we will try to address th. present ch.llenges and pitfalls related to youth.onset T2DM and summarize th. available interventions to mitigate th. risk of microvascular and macrovascular complications.

关键词： Youth.onset type 2 diabetes mellitus Insulin resistance Beta cell failure Risk factors Th.rapy Complications