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In-situ study of the microstructure evolution during tension of a mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

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Journal of magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián máthis p.ter Nagy p.ter Jenei Zoltán Hegedus Andrea Farkas Jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito Kawamura Department of materials physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of physics of materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRC)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(CALs)and nanoplates(CANaps),or complete long period stacking ordered(LpSO)*** order to reveal the deformation mechanisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and CANaps/LpSO plates.

关键词： mg-Zn-Y-Al alloy Long period stacking ordered(LpSO)phase Cluster arranged nanoplates(CANaps) Annealing Tension Dislocation density Hardening

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Niche differentiation among facultative filter feeders: Insights from invasive ponto-Caspian mysids

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Current Zoology 2024年第4期70卷 513-521页

作者： p.ter Borza Varsha Rani Csaba F.Vada Institute of Aquatic Ecology Centre for Ecological ResearchKarolina ut 29.1113 BudapestHungary Doctoral School of Biology Institute of BiologyEotvos Lorand UniversityPazmany Péter sétany 1/C1117 BudapestHungary

The degree of dietary specialization has a fundamental impact on the ecological function and interactions of suspension *** niche differentiation by food particle size is common among obligate suspension feeders,its role is not evident in facultative *** this study,we aimed at providing new insights on the matter by focusing on sympatric mysid *** mysids use different mechanisms for raptorial and filter-feeding,they represent a more adequate model system than for example,the more extensively studied *** made morpholog-ical measurements on the 4 coexisting invasive ponto-Caspian mysid species to determine the areas and mesh sizes of their *** also quantified their clearance rates on the microalga Cryptomonas *** a laboratory experiment to reveal how morphological differences manifest in their overall filtering *** found relatively small but consistent differences in the primary filter area among the species,indicating that morphological constraints due to the enclosed position of the setae might limit the possibility for *** primary filter mesh sizes were small in all 4 species(0.69-2.73μm)with moderate but consistent intraspecific differences,suggesting that the benefit of being able to capture small particles might outweigh the pressure for *** observed clearance rates were in accordance with the morphological characteristics of the species,highlighting that auxiliary filters(present in one of the species,Limnomysis benedeni)are needed to increase filtering capacity *** study confirmed that food particle size can contribute to the niche differentiation of facultative filter feeders,but also indicated that they can tolerate a higher overlap than obligate *** observed differences were related to the habitat preferences and predatory potentials of the species,suggesting that complementarity among the different niche axes might further facilitate theircoexistence.

关键词： clearance rate coexistence filter area filtermesh size.

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Selection of digital fabrication technique in the construction industry--A multi-criteria decision-making approach

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 977-997页

作者： m.p.SALAImANImAGUDAm J.JAYApRAKASH Department of Structural and Geotechnical Engineering School of Civil EngineeringVellore Institute of TechnologyVellore 632014India

Digital fabrication techniques,in recent decades,have provided the basis of a sustainable revolution in the construction ***,selecting the digital fabrication method in terms of manufacturability and functionality requirements is a complex *** paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the multi-criteria decision-making *** alternatives considered in the study are concrete three-dimensional(3D)printing,shotcrete,smart dynamic casting,material intrusion,mesh molding,injection concrete 3D printing,and thin forming *** criteria include formwork utilization,reinforcement incorporation,geometrical complexity,material enhancement,assembly complexity,surface finish,and build *** demonstrates different multi-criteria decision-making techniques,with both subjective and objective weighting *** given ranking is based on the current condition of digital fabrication in the construction *** study reveals that in the selection of digital fabrication techniques,the criteria including reinforcement incorporation,build area,and geometrical complexity play a pivotal role,collectively accounting for nearly 70% of the overall *** the evaluated techniques,concrete 3D printing emerged as the best performer,however the shotcrete and mesh molding techniques in the second and third positions.

关键词： digital fabrication multicriteria decision-making concrete 3D printing

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Seismic response of deep circular tunnels subjected to S-waves:Axial bending

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Underground Space 2024年第4期17卷 267-279页

作者： Chatuphat Savigamin Antonio Bobet Osvaldo p.m.Vitali HR Engineering Services Inc.MedleyFL 33166United States Lyles School of Civil Engineering Purdue UniversityWest LafayetteIN 47907United States Department of Civil Environmentaland Construction EngineeringUniversity of Hawaii at ManoaHonoluluHI 96822United States

Ovaling deformation of circular tunnels has received great interest from the tunneling community because this mode of seismicinduced deformation is considered the most ***,there is growing evidence that other deformation modes can also be important and thus need to be considered in *** study presents a new analytical solution to estimate axial bending(snaking),a mode of deformation caused by S-waves impinging on a tunnel parallel to the tunnel *** solution is developed using the soilstructure interaction approach with the assumption that the interface between the ground and the tunnel lining is frictionless(fullslip).Full dynamic numerical simulations are conducted to verify the new full-slip solution,together with the existing no-slip *** of dynamic amplification are also explored for both full-slip and no-slip interface conditions by changing the wavelength(or frequency)of the seismic input motions.

关键词： Seismic response of tunnels Analytical solutions Soil-structure interaction Axial bending Snaking S-waves

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Intertype superconductivity evoked by the interplay of disorder and multiple bands

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Frontiers of physics 2024年第4期19卷 81-89页

作者： p.m.marychev A.A.Shanenko A.V.Vagov HSE University 101000 MoscowRussia Center for Advanced mesoscience and Nanotechnology MIPTDolgoprudny141700Russia

Nonmagnetic impurity scattering is known to shift up the Ginzburg-Landau parameter k of a *** this case,when the system is initially in type I,it can change its magnetic response,crossing the intertype domain with k~1 between the two standard superconductivity types and arriving at type *** the present work we demonstrate that the impact of disorder can be much more profound in the presence of the multiband structure of the charge carrier *** particular,when the band diffusivities differ from each other,the intertype domain tends to expand significantly,including points with k>>1 that belong to deep type-Ⅱ in conventional single-band *** finding sheds light on the nontrivial disorder effect and significantly complements earlier results on the enlargement of the intertype domain in clean multiband superconductors.

关键词： superconductivity disorder intertype superconductivity twoband model

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Development of an active-site titrant for SARS-CoV-2 main protease as an indispensable tool for evaluating enzyme kinetics

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Acta pharmaceutica Sinica B 2024年第5期14卷 2349-2357页

作者： Rabea Voget Julian Breidenbach Tobias Claff Alexandra Hingst Katharina Sylvester Christian Steinebach Lan phuong Vu Renato H.Weiße Ulrike Bartz Norbert Sträter Christa E.müller michael Gütschow pharmaceutical Institute Pharmaceutical&Medicinal ChemistryUniversity of BonnBonn 53121Germany Institute of Bioanalytical Chemistry Center for Biotechnology and BiomedicineLeipzig UniversityLeipzig 04103Germany Department of Natural Sciences University of Applied Sciences Bonn-Rhein-SiegRheinbach 53359Germany

A titrant for the SARS-CoV-2 main protease(m^(pro))was developed that enables,for the first time,the exact determination of the concentration of the enzymatically active m^(pro) by active-site *** covalent binding mode of the tetrapeptidic titrant was elucidated by the determination of the crystal structure of the enzyme–titrant *** fluorogenic substrates of m^(pro),including a prototypical,internally quenched Dabcyl-EDANS peptide,were compared in terms of solubility under typical assay *** exploiting the new titrant,key kinetic parameters for the m^(pro)-catalyzed cleavage of these substrates were determined.

关键词： COVID-19 SARS-CoV-2 main protease peptide nitriles Fluorogenic substrates Active-site titration X-ray crystallography Inner filter effect

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mechanisms behind the environmental sensitivity of carbon fiber reinforced polytetrafluoroethylene(pTFE)

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Friction 2024年第5期12卷 997-1015页

作者： pontus JOHANSSON p.mARKLUND m.BJORLING Y.SHI Division of machine Element LuleåUniversity of TechnologyLuleåSE-97187Sweden

Carbon fiber reinforced polytetrafluoroethylene (CF/pTFE) composites are known for their exceptional tribological performance when sliding against steel or cast iron in inert gas environments. Compared to experiments in humid air, about an order of magnitude lower wear rate and several times lower coefficient of friction have been reported for tests conducted in dry nitrogen and hydrogen. moreover, trace moisture has been shown to affect the friction and wear significantly of this tribosystem, although a possible effect of oxygen cannot be ruled out due to uncertainties regarding the oxygen concentrations. While several studies have pointed out the environmental sensitivity of CF/pTFE, the understanding of the underlying mechanisms are very limited. The objective of this research is to investigate the individual and combined effect of oxygen and moisture on the tribological behavior of CF/pTFE sliding against steel. Additionally, this study aims to elucidate the underlying mechanisms that govern the environmental sensitivity of the system. Climate-controlled three-pin-on-disc experiments were conducted in nitrogen atmospheres at various concentrations of oxygen and moisture. The tribological results clearly demonstrate that both moisture and oxygen contribute to increased friction and wear. However, the adverse effect was much more pronounced for oxygen than moisture. A qualitative method was developed to estimate the tribofilm coverage on the CF/pTFE surface. Results showed strong correlation between high coverage of strongly adhered tribofilm and low wear rate. moreover, a loosely adhered tribofilm was observed on top of the CF/pTFE surface in presence of moisture. FTIR analysis indicated that the loosely adhered tribofilm found in the moisture-enriched environment contained a significant amount of adsorbed water, which may explain the lower coefficient of friction in presence of moisture compared to oxygen. The adsorbed water in the loosely adhered tribofilm coul

关键词： polymer composite tribofilm tribochemistry atmosphere

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Drought events influence nutrient canopy exchanges and green leaf partitioning during senescence in a deciduous forest

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Forest Ecosystems 2024年第1期11卷 110-119页

作者： J.Touche C.Calvaruso p.De Donato m.-p.Turpault INRAE BEFF-54000NancyFrance UmR 7359 GeoRessourcesFaculte des Sciences-Campus des Aiguillettes54506Vandoeuvre Les NancyFrance EcoSustain Environmental Engineering OfficeResearch and DevelopmentKanfen57330France

The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in *** possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced ***,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly *** experiment in a beech forest in meuse(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence *** aim was to identify potential nutritional consequences of droughts for *** nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(K)partitioning to resorption(*** efficiency),thus reducing the K reserve in trees for the next growing *** result suggests that with the increased drought frequency and intensity expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study *** foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(p)were also *** addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree *** calcium(Ca)negative resorption decreased,with no apparent consequence in our study *** results show that nutrient exchanges in the canopy and the partitioning of the green leaf

关键词： Natural drought Beech forest Canopy Resorption Foliar leaching Senesced leaves Nutrition

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Development of an ultrathin liquid sheet target for laser ion acceleration at high repetition rates in the kilohertz range

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High power Laser Science and Engineering 2024年第3期12卷 134-145页

作者： m.Füle A.p.Kovács T.Gilinger m.Karnok p.Gaál S.Figul G.marowsky K.Osvay National Laser-Initiated Transmutation Laboratory University of SzegedSzegedHungary Department of Experimental physics University of SzegedSzegedHungary ELI ALpS ELI-HU Non-Profit Ltd.SzegedHungary Department of Optics and Quantum Electronics University of SzegedSzegedHungary Advanced microfluidic Systems GmbH GöttingenGermany

A colliding microjet liquid sheet target system was developed and tested for pairs of round nozzles of 10,11 and 18μm in *** sheet's position stability was found to be better than a few *** interaction with 50 mJ laser pulses,the 18μm jet has a resonance amplitude of 16μm at a repetition rate of 33 Hz,while towards 100 Hz it converges to 10μm for all nozzles.A white-light interferometric system was developed to measure the liquid sheet thickness in the target chamber both in air and in vacuum,with a measurement range of 182 nm±1μm and an accuracy of±3%.The overall shape and 3D shape of the sheet follow the Hasson±peck model in *** vacuum versus air,the sheet gradually loses 10%of its thickness,so the thinnest sheet achieved was below 200 nm at a vacuum level of 10±4mbar,and remained stable for several hours of operation.

关键词： diagnostics laser ion acceleration nanometric liquid sheet targets vacuum test

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Tensile deformation of fine-grained mg at 4K,78K and 298K

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Journal of magnesium and Alloys 2024年第6期12卷 2534-2556页

作者： m.Walag A.Kula p.Noga T.Tokarski G.Cios m.Niewczas AGH University of Krakow Faculty of Non-Ferrous MetalsKrakowPoland AGH University of Krakow Academic Centre for Materials and NanotechnologyKrakowPoland materials Science and Engineering McMaster UniversityHamiltonCanada

The impact of grain size, ranging from 0.9 μm to 9 μm, on the mechanical properties of commercially pure mg is investigated at temperatures of 4K, 78K, and 298K. The mechanisms governing plastic flow are influenced by both grain size and temperature. At 4K and 78K, dominant deformation modes in mg involve dislocation glide and extension twinning, regardless of grain size. The interactions between basal and non-basal dislocations and dislocations with grain boundaries promote an unusually high rate of work hardening in the plastic regime, leading to premature failure. The yield stress follows the Hall-petch relationship σy~ k/√d, with the slope k increasing with decreasing temperature. At 298K, in addition to dislocation glide and twinning, grain boundary sliding(GBS) becomes significant in samples with grain sizes below 3 μm, considerably enhancing the material's deformability. GBS activation provides an additional recovery mechanism for dislocations accumulating at grain boundaries, facilitating their absorption during sliding and rotation. Analysis of σ Θ relationship suggests that the basal slip is the dominant dislocation mode in mg at 298K. Decreasing grain size suppresses dislocation activity and twinning and increases GBS, resulting in lower Θ and σ Θ values. Suppressing conventional deformation modes coupled with enhanced GBS yields stress softening, breaking down the Hall-petch relationship in mg below 3 μm grain size, leading to an inverse Hall-petch behaviour. The work reports new data on the strength, ductility, work hardening and fracture behaviour, and their variations with mg grain size across different temperature regimes.

关键词： polycrystalline mg mechanical properties Deformation mechanisms Work-hardening Texture evolution Cryogenic temperatures Hall-petch relationship

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