检索结果-南通市图书馆

Structural Ultrafine Grained Steels Obtained by Advanced Controlled Rolling

在线全文

学校读者我要写书评

暂无评论

journal of iron and Steel Research(international) 2013年第1期20卷 62-70页

作者： R González j O García M A Barbés M j Quintana L F verdeja j i verdeja School of Engineering Panamerican UniversityMexico City 03920Mexico E T S i M O Oviedo UniversityOviedo 33004Spain

Steels with ultrafine grains （lower than 5 μm）, which usually known as ultrafine ferrite or ultrafine grained materials, are presently the object of intense research, because of the improvement in resistance and fracture toughness they may reach compared to conventional steels （with grain sizes above this value）. it is shown that the forenamed steels designated in the Euronorm EN 10149-2, which are manufactured by advanced techniques of controlled rolling and mainly used in automotive industry, have an ultrafine grain size in the range of 2.5 to 3.5 μm, and with elastic yield stresses higher than 400 MPa. Based on the Morrison-Miller criterion, it is shown that values of the strain-hardening coefficient lower than 0.08 would make the industrial application of these steels unfeasible.

关键词： ultrafine grained steel mechanical property manufacturability strain-hardening

AN OPTiMAL CONTROL PROBLEM FOR A LOTKA-VOLTERRA COMPETiTiON MODEL WiTH CHEMO-REPULSiON

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2024年第2期44卷 721-751页

作者： Diana i.HERNÁNDEZ Diego A.RUEDA-GOMEZ Élder j.ViLLAMiZAR-ROA Universidad industrial de Santander Escuela de MatemáticasA.A.678BucaramangaColombia

in this paper we study a bilinear optimal control problem for a diffusive Lotka-Volterra competition model with chemo-repulsion in a bounded domain of ℝ^(ℕ),N=2,*** model describes the competition of two species in which one of them avoid encounters with rivals through a chemo-repulsion *** prove the existence and uniqueness of weak-strong solutions,and then we analyze the existence of a global optimal solution for a related bilinear optimal control problem,where the control is acting on the chemical ***,we derive first-order optimality conditions for local optimal solutions using the Lagrange multipliers ***,we propose a discrete approximation scheme of the optimality system based on the gradient method,which is validated with some computational experiments.

关键词： Lotka-Volterra chemo-repulsion optimal control optimality conditions

Constrained re-calibration of two-equation Reynolds-averaged Navier–Stokes models

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2024年第2期14卷 82-89页

作者： Yuanwei Bin Xiaohan Hu jiaqi Li Samuel j.Grauer Xiang i.A.Yang Department of Mechanical Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing 100871China College of Engineering Peking UniversityBeijing 100871China

Machine-learned augmentations to turbulence models can be advantageous for flows within the training dataset but can often cause harm *** lack of generalizability arises because the constants(as well as the functions)in a Reynolds-averaged Navier–Stokes(RANS)model are coupled,and un-constrained re-calibration of these constants(and functions)can disrupt the calibrations of the baseline model,the preservation of which is critical to the model's *** safeguard the behaviors of the baseline model beyond the training dataset,machine learning must be constrained such that basic calibrations like the law of the wall are kept *** letter aims to identify such constraints in two-equation RANS models so that future machine learning work can be performed without violating these *** demonstrate that the identified constraints are not ***,they help preserve the generalizability of the baseline model.

关键词： Machine learning Turbulence modeling Reynolds-averaged Navier-Stokes

Generalized time-dependent generator coordinate method for induced fission dynamics

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第4期19卷 1-12页

作者： B.Li D.Vretenar T.Nikšić j.Zhao P.W.Zhao j.Meng State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Physics Department Faculty of ScienceUniversity of Zagreb10000 ZagrebCroatia Center for Circuits and Systems Peng Cheng LaboratoryShenzhen 518055China

The generalized time-dependent generator coordinate method(TD-GCM)is extended to include pairing *** correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weight *** particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional,while pairing is treated dynamically in the standard BCS approximation with time-dependent pairing tensor and single-particle occupation *** the inclusion of pairing correlations,various time-dependent phenomena in open-shell nuclei can be described more *** model is applied to the description of saddle-to-scission dynamics of induced *** generalized TD-GCM charge yields and total kinetic energy distribution for the fission of 240Pu,are compared to those obtained using the standard time-dependent density functional theory(TD-DFT)approach,and with available data.

关键词： nuclear density functional theory generator coordinate method fission dynamics

Dominance of transposable element‑related satDNAs results in great complexity of“satDNA library”and invokes the extension towards“repetitive DNA library”

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Marine Life Science & Technology 2024年第2期6卷 236-251页

作者： Monika Tunjić‑Cvitanić Daniel García‑Souto juan j.Pasantes EvaŠatović‑Vukšić Division of Molecular Biology Ruđer BoškovićInstitute10000 ZagrebCroatia Genomes and Disease Centre for Research in Molecular Medicine and Chronic Diseases(CIMUS)Universidade de Santiago de Compostela15706 Santiago de CompostelaSpain Department of Zoology Genetics and Physical AnthropologyUniversidade de Santiago de Compostela15706 Santiago de CompostelaSpain Centro de investigación Mariña Dpto de BioquímicaXenética e InmunoloxíaUniversidade de Vigo36310 VigoSpain

Research on bivalves is fast-growing,including genome-wide analyses and genome *** characteristics qualify oysters as a valuable model to explore repetitive DNA sequences and their genome *** we char-acterize the satellitomes of five species in the family Ostreidae(Crassostrea angulata,***,***,***,Ostrea edulis),revealing a substantial number of satellite DNAs(satDNAs)per genome(ranging between 33 and 61)and peculiarities in the composition of their *** satDNAs were either associated to or derived from transposable elements,displaying a scarcity of transposable element-unrelated satDNAs in these *** to the non-conventional satellitome constitution and dominance of Helitron-associated satDNAs,comparative satellitomics demanded more in-depth analyses than standardly *** analyses(including ***,the first bivalve species with a defined satellitome)revealed that 13 satDNAs occur in all six oyster genomes,with Cg170/Hindiii satDNA being the most abundant in all of *** the“satDNA library model”highlighted the necessity to adjust this term when studying tandem repeat evolution in organisms with such *** repetitive sequences with potential variation in the organizational form and repeat-type affiliation are examined across related species,the introduction of the terms“TE library”and“repetitive DNA library”becomes essential.

关键词： Satellitome Comparative satellitomics Helitron Bivalves “Dark matter of the genome”

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Materials Science 2024年第2期6卷 193-200页

作者： M.i.ikim G.N.Gerasimov V.F.Gromov O.j.ilegbusi L.i.Trakhtenberg N.N.Semenov Federal Research Center for Chemical Physics of RAS MoscowRussia University of Central Florida OrlandoFLUSA Moscow institute of Physics and Technology(State University) DolgoprudnyMoscow RegionRussia Lomonosov Moscow State University MoscowRussia

The hydrothermal synthesis of in_(2)O_(3)and CeO_(2)–in_(2)O_(3)is investigated as well as the properties of sensor layers based on these *** the synthesis of in_(2)O_(3),intermediate products in(OH)_(3)and inOOH are formed,which are the precursors of stable cubic(c-in_(2)O_(3))and metastable rhombohedral(rh-in_(2)O_(3))phases,respectively.A transition from c-in_(2)O_(3)to rh-in_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-in_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-in_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-in_(2)O_(3).The reverse situation is observed in composites based on c-in_(2)O_(3).Compared to in_(2)O_(3)and CeO_(2)–in_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between in_(2)O_(3)and CeO_(2).

关键词： Cerium oxide indium oxide Nanocomposite Hydrothermal method Cubic phase Rhombohedral phase Sensor response Conductivity Hydrogen Response/recovery time

Physical activity volume,frequency,and intensity:Associations with hypertension and obesity over 21 years in Australian women

在线全文

学校读者我要写书评

暂无评论

journal of Sport and Health Science 2024年第5期13卷 631-641页

作者： Gregore i.Mielke Ding Ding Shelley E.Keating Bruno P.Nunes Ruth Brady Wendy j.Brown School of Public Health The University of QueenslandBrisbaneQLD 4006Australia Sydney School of Public Health Faculty of Medicine and HealthThe University of SydneySydneyNSW 2006Australia The Charles Perkins Centre The University of SydneySydneyNSW 2006Australia School of Human Movement and Nutrition Sciences The University of QueenslandBrisbaneQLD 4072Australia School of Nursing Federal University of PelotasPelotasRio Grande do Sul 96010-610Brazil Faculty of Health Sciences and Medicine Bond UniversityGold CoastQLD 4226Australia

Background:Optimal patterns of accrual of recommended levels of physical activity(PA)for prevention of hypertension and obesity are not *** overall aim of this study was to investigate whether different patterns of accumulation of PA are differentially associated with hypertension and obesity in Australian women over 21 ***,we investigated whether,for the same weekly volume of PA,the number of sessions(frequency)and vigorousness of PA(intensity)were associated with a reduction in the occurrence of hypertension and obesity in ***:Data from the 1973-1978 and 1946-1951 cohorts of the Australian Longitudinal Study on Women's Health were analyzed(n=20,588;12%-16%with a Bachelor's or higher degree).Self-reported PA,hypertension,height,and weight were collected using mail surveys every 3 years from 1998/2000 to 2019/*** Estimating Equation models with a 3-year lag model were used to investigate the association of PA volume(metabolic equivalent min/week)(none;33-499;500-999;≥1000,weekly frequency(none;1-2 times;3-4times;5-7 times;≥8 times),and the proportion of vigorous PA to total volume of PA(none;0%;1%-33%;34%-66%;67%-100%)with odds of hypertension and obesity from 2000 to ***:The cumulative incidence of hypertension was 6%in the 1973-1978 and 23%in the 1946-1951 cohort;27%of women in the 1973-1978;and 15%in the 1946-1951 cohort developed obesity over the ***,a higher volume of PA was associated with reduced odds of hypertension and *** the volume of PA was considered,the odds of hypertension did not vary according to the frequency or intensity of ***,increased proportion of vigorous PA to the total volume of PA was associated with a small additional reduction in the risk of obe ***:PA volume appears to be more important than the pattern of accumulation for the prevention of hypertension and *** more sessions,particularly of vigorous-intensity PA,may provide extr

关键词： Physical activity Frequency intensity incidences Epidemiology Women

Experimental test of a building thermal system for preventive maintenance based on thermoeconomic analysis

在线全文

学校读者我要写书评

暂无评论

Energy Storage and Saving 2024年第1期3卷 42-51页

作者： i.Prol-Godoy A.Picallo-Perez j.M.Sala-Lizarraga j.Rey-Martínez Research group ENEDi Department of Thermal EngineeringUniversity of the Basque Country(UPV/EHU)Bilbao48013Spain Research Group Termotecnia University of ValladolidValladolid47002Spain

An analysis of the sectorial structure of energy consumption shows that residential and tertiary sector buildings are the third-highest consumers,responsible for 29.5%of a city’s final energy *** Building Quality Control Laboratory of the Basque Government aims to promote quality,innovation,and sustainability in *** accomplish this goal,it has constructed an experimental facility with different energy generation technologies and a very versatile control system for testing different energy systems and operation *** this study,we tested a facility for supplying domestic hot water and heating for a multi-family house by means of a condensing boiler and an aerothermal heat pump(together with the corresponding control).This installation could reproduce the thermal demands required to be satisfied by the generation equipment through a programmed operation of the installation based on real ***,this installation was analyzed using thermoeconomics(TE)to solve problems unable to be solved using traditional energy analyses based on the First Law of *** problems include:(1)Determining the costs of the products of the installation based on physical criteria,(2)detecting the places where losses actually occur,evaluating their costs,and proposing cost-effective improvements,and(3)diagnosing issues in the *** a result,this paper suggests a solution to the preventive maintenance problems confronting the technical maintenance personnel for thermal installations in buildings by applying TE knowledge and using real data collected from sensors.

关键词： Experimental essay Energy savings in thermal systems Thermoeconomics Thermoeconomic costs Diagnosis

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2024年第3期7卷 277-291页

作者： i.A.O.Beeren G.Dos Santos P.j.Dijkstra C.Mota j.Bauer H.Ferreira Rui L.Reis N.Neves S.Camarero-Espinosa M.B.Baker L.Moroni Department of Complex Tissue Regeneration MERLN Institute for Technology-Inspired Regenerative MedicineMaastricht University6229 ER MaastrichtThe Netherlands 3B’s Research Group I3Bs–Research Institute on BiomaterialsBiodegradables and BiomimeticsHeadquarters of the European Institute of Excellence on Tissue Engineering and Regenerative MedicineUniversity of MinhoAveParkZona Industrial da Gandra4805-017 BarcoGuimarãesPortugal iCVS/3B’s-PT Government Associate Laboratory 4806-909 Braga/GuimarãesPortugal POLYMAT University of the Basque Country UPV/EHU20018 Donostia/San SebastiánSpain iKERBASQUE Basque Foundation for Science48009 BilbaoSpain

Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering ***,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell *** of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface ***,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different *** porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL *** a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was *** two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor ii(BMPRii)on films with the conjugated *** addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface *** together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material ***,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(m

关键词： Additive manufacturing Blending Surface functionalization Surface density Click chemistry Human