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Dynamic and electrical responses of a curved s.ndwich beam with glass reinforced laminate layers and a pliable core in the pres.nce of a piezoelectric layer under low-velocity impact

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 155-178页

作者： n.sHAHVEIsI s.FELI Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

The dynamic responses and generated voltage in a curved s.ndwich beam with glass reinforced laminate(GRL)layers and a pliable core in the pres.nce of a piezoelectric layer under low-velocity impact(LVI)are *** current study aims to carry out a dynamic analysis on the s.ndwich beam when the impactor hits the top face sheet with an initial *** the layer analysis,the high-order shear deformation theory(HsDT)and Frostig's second model for the displacement fields of the core layer are *** classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of *** order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the *** element(FE)simulations are conducted by means of the ABAQUs *** effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.

关键词： analytical model piezoelectric layer curved s.ndwich beam glass reinforced laminate(GRL) pliable core low-velocity impact(LVI) classical non-adhesive elastic contact theory

Metagenomic analysis revealing the metabolic role of microbial communities in the free amino acid bios.nthesis of Monascus rice vinegar during fermentation

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Food science and Human Wellness 2024年第4期13卷 2317-2326页

作者： Hang Gao Jian Zhang Li Liu Lijun Fu yan Zhao Germán Mazza Xin Zhang Beijing Academy of Food sciences 100068 BeijingChina Institute for Research and Development in Process Engineering Biotechnology and Alternative Energies(PROBIENCONICET-UNCo)8300 NeuquénArgentina

Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer *** is one of the major metabolites produced by microorganisms;however,the microbial metabolic network on FAA bios.nthesis remains *** metagenomic analysis,this work aimed to elucidate the roles of microbes in FAA bios.nthesis during Monascus rice vinegar *** profiles from functional analyses showed 14 dominant genera with high contributions to the metabolism *** metabolic network for FAA bios.nthesis was then constructed,and the microbial distribution in different metabolic pathways was *** results revealed that 5 functional genera were closely involved in FAA *** study illuminated the metabolic roles of microorganisms in FAA bios.nthesis and provided crucial insights into the functional attributes of microbiota in vinegar fermentation.

关键词： Monascus rice vinegar Metagenomic analysis Free amino acid s.nthesis Metabolic pathway Microbial distribution

An Integral Method for solving Dynamic Equations with Fluid–solid Coupling

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Acta Mechanica solida s.nica 2024年第1期37卷 99-108页

作者： Xin Zhang Jie Liu Pu Xue shuowen yan Yahao Xu M.s.Zahran school of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China school of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China Department of Civil Engineering Military Technical CollegeCairo 11435Egypt

In this work,a new methodology is pres.nted to mainly solve the fluid–solid interaction(FsI)*** methodology combines the advantages of the newmark precise integral method(nPIM)and the dual neural network(Dnn)*** nPIM is employed to modify the exponential matrix and loading vector based on the Dnn integral *** involves incorporating the basic assumption of the newmark-βmethod into the dynamic equation and eliminating the acceleration term from the dynamic equilibrium *** a result,the equation is reduced to a first-order linear equation ***,the PIM is applied to integrate the system step by step within the *** Dnn method is adopted to solve the inhomogeneous term through fitting the integrand and the original function with a pair of neural networks,and the integral term is solved us.ng the newton–Leibniz *** examples demonstrate that the proposed methodology significantly improves computing efficiency and provides sufficient precision compared to the Dnn *** is particularly evident when analyzing large-scale structures under blast loading conditions.

关键词： newmark precise integral method(nPIM) Dual neural networks(Dnn) Fluid-solid interaction(FsI) Dynamic time-history analysis Blast loading

Towards defining soil quality of Mediterranean calcareous agricultural soils:Reference values and potential core indicator set

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International soil and Water Conservation Research 2024年第1期12卷 145-155页

作者： Germán A.Durán Daniel sacristán Edelweis Farrús Jaume Vadell Institut de Recerca i FormacióAgrària i Pesquera de les Illes Balears C/Eusebi Estada14507009PalmaSpain Plant Biology Department University of Valencia46100BurjassotValenciaSpain soil and Environmental Quality Department Centro de Investigaciones sobre Desertificación-CIDE(CSIC-Universitat de València-Generalitat Valenciana)Carretera Moncada-Náquera km 4.546113MoncadaValenciaSpain Universitat de les Illes Balears Cra.De Valldemossakm 7507122PalmaSpain

To avoid soil degradation,adapt to climate change and comply with the sustainable Development goals 2030(Un General Assembly),establishing the quality/fertility of the agricultural soils of the Mediterranean region and evaluate how these evolve with time is *** enables adequate management practices to be *** Mediterranean calcareous region has received little attention in this s.nse,in spite its soil ***,24 different repres.ntative calcareous agricultural soils of the Mediterranean region,including the main management strategies of agricultural soils(rainfed and irrigated),were sampled from the island of Mallorca;and their physical,chemical and biological properties *** values obtained for most of the soil characteristics allowed to establish an initial approach to the reference values for the type of calcareous agricultural soils considered,and to clearly distinguish the effect of rainfed or irrigation management practices on soils properties and *** enzyme activities were not stimulated by the irrigation conditions assayed or they were only in dry conditions,suggesting optimum enzyme activities could be obtained when alternating dry and humid soil *** organic carbon,calcium carbonate and active lime revealed of significant importance in the collection of ***,the results obtained clearly indicate the heterogeneity of the region and its implications on the different soil ***,this study could serve as a starting point to adequately establish the quality(fertility)for Mediterranean calcareous agricultural soils and their reference values by conducting further research in this region and including more type of soils.

关键词： soil fertility Mediterranean agricultural soils Calcareous soils soil enzymes soil management

Early Phases of star Formation: Testing Chemical Tools

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Research in Astronomy and Astrophysics 2024年第1期24卷 96-118页

作者： n.C.Martinez s.Paron COnICET-Universidad de Buenos Aires.Instituto de Astronomía y Física del Espacio Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

star-forming processes strongly influence the IsM ***,many high-quality databases are available at millimeter *** them,it is possible to carry out studies that review and deepen previous *** these studies involve large samples of sources,it is preferred to use direct tools to study the molecular *** the aim of testing these tools such as the use of the HCn/HnC ratio as a thermometer,and the use of H^(13)CO^(+),HC_(3)n,n_(2)H^(+) and C_(2)H as "chemical clocks," we pres.nt a molecular line study toward 55 sources repres.nting massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDCs),highmass protostellar objects(HMPOs),hot molecular cores(HMCs) and ultracompact H II *** found that the use of the HCn/HnC ratio as a universal thermometer in the IsM should be taken with care because the HCn optical depth is a big issue that can affect the ***,this tool should be utilized only after a careful analysis of the HCn spectrum,checking that no line,neither the main nor the hyperfine ones,pres.nts absorption *** point out that the analysis of the emission of H^(13)CO^(+),HC_(3)n,n_(2)H^(+) and C_(2)H could be useful to trace and distinguish regions among IRDCs,HMPOs and *** molecular line widths of these four species increase from the IRDC to the HMC stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular *** results.not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.

关键词： stars:formation IsM:molecules IsM:clouds

Electromagnetic characteristic analysis and design of a linear motor used for ultra-high-speed EMs maglev train

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science China(Technological sciences) 2024年第6期67卷 1957-1973页

作者： GAO Han sHI Tingna GAO XinMai LEI yanXiao yan Dong GUO Liyan yan yan College of Electrical Engineering Zhejiang UniversityHangzhou310027China Zhejiang University Advanced Electrical Equipment Innovation Center Hangzhou311107China state Key Laboratory of High-speed Maglev Transportation Technology Qingdao266100China CRRC Qingdao sifang Co.Ltd. Qingdao266111China

The operating speed of the commercial electromagnetic suspension(EMs)maglev train has been over 430 km/h,making it the fastest means of land *** the increas.ng demands of people traveling,it is.necessary to further improve the operating speed of maglev *** to examine whether the existing EMs system can meet the requirements of ultra-highspeed operation(more than 600 km/h),the electromagnetic characteristics of an EMs linear motor under the operating speed of 600–1000 km/h fed by a square-wave voltage supply is investigated in this ***,an electromagnetic field model of the EMs system under the square-wave voltage supply is established to investigate its electromagnetic performance,e.g.,the characteristics of phase current,the magnetic flux density,and the electromagnetic ***,the relationship between the harmonic components of the air-gap magnetic flux density and electromagnetic force is investigated us.ng the two-dimensional fast Fourier transform(2D-FFT)to reveal the mechanism of electromagnetic force ***,to address the issues of excessive armature current density and significant electromagnetic force ripple,the linear motor is re-designed by enlarging the stator slot area and reshaping the mover's main magnetic ***,the Taguchi method is used to further improve the electromagnetic characteristics of the linear electric ***,the effectiveness of the proposed optimal design is validated by the finite-element analysis(FEA)based co-simulation.

关键词： ultra-high-speed maglev transportation electromagnetic suspension(EMs) linear motor electromagnetic force ripple suppression

numerical simulation of fluid flow and free surface fluctuations during wheel and belt casting process

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Journal of Iron and steel Research International 2024年第5期31卷 1117-1126页

作者： Kun Gao yan Peng national Engineering Research Center for Equipment and Technology of Cold strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

The unstable fluid flow and severe free surface fluctuations in the wheel and belt caster can affect the quality of the cast *** lower level height tends to entrap inclusions in the molten *** the other hand,the higher level height makes the production process more dangerous due to the overflow of high temperature fluid from the mold.A computational model of the molten metal pouring process was *** transient fluid flow and free surface fluctuations behavior were calculated us.ng the three-dimensional large eddy simulation model and the volume of fluid *** results show that the flow velocity of the main jet gradually decreases under the influence of the low kinetic energy fluid in the *** is an obvious oscillation in the tail of the jet,while the flow field is asymmetric in *** jet is closer to the inside radius side due to the Coanda effect,and there is a recirculation zone on the inside radius and the outside radius respectively,according to the 10 s time-averaged *** with the industrial observation and simulation results,the shape of the free surface is a wave that varies with *** addition,the free surface height is lowest and the flow velocity is highest in the region near the jet.

关键词： Fluid flow Free surface Wheel and belt caster Large eddy simulation Volume of fluid method

Plant type effect overweighs seas.nal variation in n-alkanoic acid biomarker on regional Loess Plateau of China

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science China Earth sciences 2024年第8期67卷 2547-2562页

作者： Jinzhao LIU s.nemiah LADD Jiaju ZHAO Dongna yan Ding HE Yunning CAO Zhisheng An state Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China CAs Center for Excellence in Quaternary science and Global Change Xi’an 710061China Department of Environmental sciences University of BaselBasel 4056Switzerland Department of Ocean science and Center for Ocean Research in Hong Kong and Macao The Hong Kong University of Science and TechnologyHong Kong 999077China

The effect of plant type on n-alkane biomarker has been widely studied,but the influence of plant type on n-alkanoic acids.n-FAs)has received less *** the effect of the distribution of n-FAs and their hydrogen isotope composition(δ^(2)H_(FA))is critical for interpreting sedimentaryδ^(2)H_(FA)values as proxies of hydroclimate and/or vegetation *** this study,we systematically investigated the distribution ofn-FAs andδ^(2)H_(FA)values across seas.ns on the Chinese Loess Plateau(CLP).Our results showed that there were no significant seas.nal differences in n-FAs distribution andδ^(2)H_(FA)values,but there were significant differences inδ^(2)H_(FA)values across plant ***δ^(2)H_(FA)values ranged from-185‰to-125‰in dicots(-161‰±28‰),and from-215‰to-170‰in monocots(-196‰±22‰)on the *** fractionation betweenδ^(2)H_(FA)values and precipitationδ^(2)H(ε_(FA-P))was also^(2)H-enriched in dicots relative to *** the regional scale of the CLP,δ^(2)H_(FA)values were not correlated withδ^(2)H values of ***,δ^(2)H_(FA)values from the CLP were similar to expectations from a global comparis.n,both in terms of their mean values and high variability among plants growing in sites with similarδ^(2)H values of *** some of this variability inεFA-Pis due to the effect of plant type,a careful assessment of the likely sources of waxes in terrestrial sediments is critical when us.ngδ^(2)H_(FA)values for paleohydroclimate reconstruction.

关键词： n-Alkanoic acid Hydrogen isotope Plant type Paleohydroclimate Chinese Loess Plateau

Ultra-flexible all-in-one anti-freeze photothermally enhanced supercapacitors

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nano Research 2024年第8期17卷 7221-7229页

作者： Yongxin Lu Keke Li yan-yan s.ng Zhida Gao Condense matter of physics College of ScienceNortheazistern UniversityShenyang 110004China

Wearable electronics powered by flexible energy storage devices have captured global *** low-temperature conditions,unfortunately,solidification of flexible hydrogel electrolyte and decreased pseudo-capacity of these devices largely hamper their practical *** this study,photothermally-active Prussian blue(PB)was introduced onto poly(3,4-ethylenedioxythiophene)/polyacrylamide(PEDOT/PAM)networks to address the challenges of electrolyte solidification and degraded pseudo-capacitance for flexible all-in-one device at low *** as-constructed PB/PEDOT/PAM hydrogel device delivers stable electrochemical performance and remarkable mechanical property with 1652%***,this hydrogel device well retains its flexibility in cold environment with a freezing point below−30℃.The incorporation of PB extends the voltage range to 1.5 V as a s.ngle device,thus significantly enhancing the electrochemical performance as an all-inone integrated *** from the outstanding photo-to-thermal conversion ability of embedded PB nanocubes,the temperature of the assembled all-in-one PB/PEDOT/PAM device increased from^(−2)0 to 17.7℃ after solar-light irradiation for only 5 ***,the degraded pseudo-capacitance was subsequently boosted to 287.1%of its original capacitance at−20℃.This study establishes a connection between flexible all-solid-state hydrogel devices and photothermally enhanced pseudocapacitors in freezing environments,thereby expanding the potential applications of multi-functional pseudo-capacitors.

关键词： all-in-one energy storage devices all-solid-state photothermal flexible low temperatures