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superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong s.w.Lee w.J.Kim Department of Materials science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 K.The microstructural refinement of this alloy was achieved by employing high-ratio differential speed rolling.The best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were obtained.During the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 K.Therefore,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and mechanisms.In the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation mechanism.It was concluded that solute drag creep is unlikely to occur.During the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain hardening.Deformation mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy superplasticity severe plastic deformation Grain size Grain growth

Pervasive Attentive Neural Network for Intelligent Image Classification Based on N-CDE’s

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Computers, Materials & Continua 2024年第4期79卷 1137-1156页

作者： Anas w.Abulfaraj Department of Information systems Faculty of Computing and Information TechnologyKing Abdulaziz UniversityRabigh21911Saudi Arabia

The utilization of visual attention enhances the performance of image classification tasks.Previous attentionbased models have demonstrated notable performance,but many of these models exhibit reduced accuracy when confronted with inter-class and intra-class similarities and differences.Neural-Controlled Differential Equations(N-CDE’s)and Neural Ordinary Differential Equations(NODE’s)are extensively utilized within this context.NCDE’s possesses the capacity to effectively illustrate both inter-class and intra-class similarities and differences with enhanced clarity.To this end,an attentive neural network has been proposed to generate attention maps,which uses two different types of N-CDE’s,one for adopting hidden layers and the other to generate attention values.Two distinct attention techniques are implemented including time-wise attention,also referred to as bottom N-CDE’s;and element-wise attention,called topN-CDE’s.Additionally,a trainingmethodology is proposed to guarantee that the training problem is sufficiently presented.Two classification tasks including fine-grained visual classification andmulti-label classification,are utilized to evaluate the proposedmodel.The proposedmethodology is employed on five publicly available datasets,including CUB-200-2011,ImageNet-1K,PAsCAL VOC 2007,PAsCAL VOC 2012,and Ms COCO.The obtained visualizations have demonstrated that N-CDE’s are better appropriate for attention-based activities in comparison to conventional NODE’s.

关键词： Differential equations neural-controlled DE image classification attention maps N-CDE’s

The CCD instrument background of the sMILE sXI

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Earth and Planetary Physics 2024年第1期8卷 15-24页

作者： M.w.J.Hubbard O.Hetherington D.J.Hall T.w.Buggey s.Parsons T.Arnold A.Holland C.Pagani s.sembay Centre for Electronic Imaging The Open UniversityMilton KeynesMK76AAUK X-ray and Observational Astronomy Group Department of Physics&AstronomyUniversity of LeicesterLE17RHUK

The EsA and CAs sMILE mission orbit is highly elliptical and will pass through multiple radiation environments.The soft X-ray Imager(sXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is high.The shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen Belts.Therefore,two radiation environments can be approximated based on the shutter door position:open and closed.The instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the sXI were evaluated for the two environments.Due to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two extremes.The results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar maxima.This is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.

关键词： instrument background X-ray astronomy space radiation

Detection and clearance in Alzheimer’s disease: leading with illusive chemical, structural and morphological features of the targets

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Neural Regeneration Research 2024年第3期19卷 497-498页

作者： Luís Gales i3s−Instituto de Investigação e Inovação em saúde Rua Alfredo AllenPortoPortugal(Gales L)IBMC−Instituto de Biologia Molecular e CelularUniversidade do PortoRua Alfredo AllenPortoPortugal ICBAs−Instituto de Ciências Biomédicas Abel salazar Rua de Jorge Viterbo FerreiraPortoPortugal

Highly specific interactions between biomolecules,such as antigen-antibody,protein-ligand,or nucleic acid base pair complementary are on the basis of the organization of complex organisms.The same principles may be tentatively used in molecular medicine for diagnosis and therapeutics.A molecule can be designed to selectively bind a protease and thereby inhibit the production of a peptide that forms toxic aggregates in the brain or an antibody may be produced to bind specifically to that peptide for detection or clearance purposes.Unfortunately,interference in biological systems is not that simple.For a start there is the inhibition of the physiological role of the protease;moreover,several cleavage fragments may be produced,which may continue to diverge due to putative post-translational modification and self-assembly processes,hiding the toxic target in a“soup”of peptide species varying in size,structure and chemical composition.A perspective of the current status and challenges in targeting peptide species for diagnosis and treatment in the context of Alzheimer’s disease is given.

关键词： Alzheimer diagnosis thereby

Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adjusting Y addition

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Journal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： J.A.Liu s.J.Liu B.wang w.B.sun X.J.Liu Z.w.Han College of Materials science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of Bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China weihai Institute for Bionics-Jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption characteristics.several characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second phase.Compressive tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous Mg-Zn-Y.The experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second phase.when the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),w-phase(Mg_(3)Zn_(3)Y_(2)),and LPsO phase(Mg_(12)ZnY).when the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 MJ/m^(3)to 10.97 MJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second phase.However,the average energy absorption efficiency is independent of the Y content.In addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered by the testing temperature.The compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the struts.The deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

sMILE soft X-ray Imager flight model CCD370 pre-flight device characterisation

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Earth and Planetary Physics 2024年第1期8卷 25-38页

作者： s.Parsons D.J.Hall O.Hetherington T.w.Buggey T.Arnold M.w.J.Hubbard A.Holland Centre for Electronic Imaging the Open UniversityMilton KeynesMK76AAUK

Throughout the sMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance level.Three CCDs have been characterised,the two flight devices and the flight spa re.This has been carried out at the Open University in a bespo ke cleanroom measure ment facility.The results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe rature.However at the nominal ope rating tempe rature(-120℃) it is within the procure ment specifications.Overall,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science mode.The se rial charge transfer inefficiency degrades with temperature in full frame mode.However any charge losses are recovered when binning/frame transfer is implemented.

关键词： CCD soft X-ray imager characterisation sMILE

Effect of Eu^(3+),Bi^(3+),and Li^(+) doping on luminescent property of GdNbO_(4)

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Journal of Rare Earths 2024年第1期42卷 66-75,I0003页

作者： s.w.wi Y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil UniversitySeoul06978Republic of Korea

we investigated the emission properties of Eu^(3+)-doped GdNbO_(4)-based oxide phosphors,aiming at improving the Eu^(3+)emission by codoping of Bi^(3+)and Li^(+).Eu^(3+)singly doped,Eu^(3+)and Bi^(3+)doubly doped,and Eu^(3+),Bi^(3+),and Li^(+)triply doped GdNbO_(4)were prepared using a high-temperature solid-state reaction method.The red-orange emissions from Eu^(3+)in the singly doped samples are significantly improved by the codoping of Bi^(3+),mainly due to the energy transfer from Bi^(3+)to Eu^(3+).The additional codoping of Li^(+)is found to increase the Eu^(3+)emission significantly.This improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu^(3+)in GdNbO_(4)does not change significantly with the codoping of Bi^(3+)and Li^(+).Our results indicate that Li^(+)doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO_(4)phosphors.

关键词： Eu^(3+) GdNbO_(4) Codoping of Li^(+) Photoluminescence sensitizer Rare earths

seasonal changes in Hermit Thrush (Catharus guttatus) song syntax

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Avian Research 2024年第2期15卷 172-179页

作者： sean P.Roach Luke C.McLean Jeff w.MacLeod Leslie s.Phillmore Psychology Department University of New Brunswick Saint John100 Tucker Park RoadSaint JohnNBCanada Department of Psychology and Neuroscience Dalhousie University1355 Oxford StHalifaxNSB3H 4J1Canada

In many songbird species,birdsong features phonological syntax,meaning that the units within their vocal se-quences are ordered in a non-random way that adheres to a rule.while such syntactical patterns have been richly described in many species,comparatively little is known about how those patterns contribute to song achieving its important functions.For each of song’s main functions,territorial defense and mate attraction,evidence of a role for syntax is limited.One species for which syntax has been thoroughly described is the Hermit Thrush(Catharus guttatus),which presents song types from their repertoires in a semi-predictable order and,in doing so,rapidly cycle up and down the frequency spectrum.The objective of the present study was to explore the importance of song syntax in the Hermit Thrush through a within-subject examination of how measures of syntax,such as the predictability of song type order within song sequences,shift over the breeding season.we hypothesized that,if such syntactical characteristics are important to breeding behaviour,they would be most prominent at the start of the breeding season when activity associated with territory establishment and mate attraction is most intense.Analysis revealed that,as predicted,the rigidness of song type ordering within se-quences was highest at the start of the season and declined thereafter.That song type sequences were most predictable at the vitally important early part of the breeding season fit our hypothesis that this aspect of song syntax is important to song’s functions related to territory establishment and/or mate attraction.Future work will clarify whether that role relates to one of song’s two main functions or serves song transmission in some broader way.

关键词： Birdsong Hermit Thrush seasonal change stereotypy syntax

It’s not all in your feet: Improving penalty kick performance with humanavatar interaction and machine learning

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The Innovation 2024年第2期5卷 115-121页

作者： Jean-Luc Bloechle Julien Audiffren Thibaut Le Naour Andrea Alli Dylan simoni Gabriel wüthrich Jean-Pierre Bresciani Control and Perception Laboratory University of FribourgBd Perolles 901700 FribourgSwitzerland Motion-up Le PrismePlace Albert Einstein56000 VannesFrance FC Basel 1893 Birsstrasse 320A4002 BaselSwitzerland

Penalty kicks are increasingly decisive in major international football competitions.Yet,over 30%of shootout kicks are missed.The outcome of the kick often relies on the ability of the penalty taker to exploit anticipatory movements of the goalkeeper to redirect the kick toward the open side of the goal.Unfortunately,this ability is difficult to train using classical methods.we used an augmented reality simulator displaying an holographic goalkeeper to test and train penalty kick performance with 13 young elite players.Machine learning algorithms were used to optimize the learning rate by maintaining an optimal level of training difficulty.Ten training sessions of 20 kicks reduced the redirection threshold by 120 ms,which constituted a 28%reduction with respect to the baseline threshold.Importantly,redirection threshold reduction was observed for all trained players,and all things being equal,it corresponded to an estimated 35%improvement of the success rate.

关键词： kick penalty learning