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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 0.9μm to 9μm,on the mechanical properties of commercially pure mg is investigated at temperatures of 4K,78K,and *** mechanisms governing plastic flow are influenced by both grain size and *** 4K and 78K,dominant deformation modes in mg involve dislocation glide and extension twinning,regardless of grain *** 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 *** yield stress follows the Hall-Petch relationshipσ_(y)∼k/√d,with the slope k increasing with decreasing *** 298K,in addition to dislocation glide and twinning,grain boundary sliding(GBS)becomes significant in samples with grain sizes below 3μm,considerably enhancing the material’s *** activation provides an additional recovery mechanism for dislocations accumulating at grain boundaries,facilitating their absorption during sliding and *** ofσrelationship suggests that the basal slip is the dominant dislocation mode in mg at *** grain size suppresses dislocation activity and twinning and increases GBS,resulting in lowerandσ*** conventional deformation modes coupled with enhanced GBS yields stress softening,breaking down the Hall-Petch relationship in mg below 3μm grain size,leading to an inverse Hall-Petch *** 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

Adaptation in brain structure and respiratory and olfactory structures across environmental gradients in African and North American muroid rodents

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Integrative Zoology 2024年第1期19卷 165-181页

作者： Peter J.TAYLOR Aluwani NENGOVHELA Christiane dENYS Graham R.SCOTT Catherine m.IVY department of Zoology School of Natural and Mathematical SciencesUniversity of VendaThohoyandouSouth Africa Afromontane Unit Department of Zoology and EntomologyUniversity of the Free StatePhuthaditjhabaSouth Africa department of mammalogy National MuseumBloemfonteinSouth Africa Institut de Systématique EvolutionBiodiversité(ISYEB)Muséum National d’Histoire NaturelleCNRSSorbonne UniversitéEPHEUniversitéDes AntillesParisFrance department of Biology McMaster UniversityHamiltonOntarioCanada Guglielmo and Shoemaker Labs Advanced Facility for Avian ResearchUniversity of Western OntarioLondonOntarioCanada

morphometric studies of 3d micro CT-scanned images can provide insights into the evolution of the brain and sensory structures but such data are still scarce for the most diverse mammalian order of *** reviewed and new data,we tested for convergence to extreme aridity and high elevation in the sensory and brain morphology of rodents,from morphometric data from micro-CT X-ray scans of 174 crania of 16 species of three distantly re-lated African murid(soft-furred mice,Praomyini,laminate-toothed rats,Otomyini,and gerbils,Gerbillinae)clades and one North American cricetid(deer mice and white-footed mice,Peromyscus)*** studies demon-strated convergent evolution acting on the oval window area of the cochlea(enlarged in extremely arid-adapted species of Otomyini and Gerbillinae)and on endocranial volume(reduced in high elevation taxa of Otomyini and Peromyscus).However,contrary to our predictions,we did notfind evidence of convergence in brain struc-ture to aridity,or in the olfactory/respiratory system(turbinate bones)to high *** structure differed,particularly in the petrosal lobules of the cerebellum and the olfactory bulbs,between Otomyini and Gerbillinae,with extreme arid-adapted species in each clade being highly divergent(not convergent)from other species in the same *** observed greater“packing”of the maxillary turbinate bones,which have important respiratory functions,in Peromyscus mice from high and low elevations compared to the high-elevation African Praomyini,but more complex patterns within Peromyscus,probably related to trade-offs in respiratory physiology and heat exchange in the nasal epithelium associated with high-elevation adaptation.

关键词： 3d morphometrics Africa brain size North America Rodentia sensory evolution

Comparison of methods for deriving phenotypes from incomplete observation data with an application to age at puberty in dairy cattle

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Journal of Animal Science and Biotechnology 2024年第2期15卷 535-545页

作者： melissa A.Stephen Chris R.Burke Jennie E.Pryce Nicole m.Steele Peter R.Amer Susanne meier Claire V.C.Phyn dorian J.Garrick dairyNZ Ltd 605 Ruakura RoadHamilton 3240New Zealand AL Rae Centre for Genetics and Breeding-massey University RuakuraHamilton 3214New Zealand Agriculture Victoria Research AgriBioCentre for AgriBioscienceBundooraVictoria 3083Australia School of Applied Systems Biology La Trobe UniversityBundooraVictoria 3083Australia AbacusBio DunedinNew Zealand

Background many phenotypes in animal breeding are derived from incomplete measures,especially if they are challenging or expensive to measure *** include time-dependent traits such as reproductive status,or *** measures for these traits result in phenotypes that are subject to left-,interval-and rightcensoring,where phenotypes are only known to fall below an upper bound,between a lower and upper bound,or above a lower bound *** we compare three methods for deriving phenotypes from incomplete data using age at first elevation(>1 ng/mL)in blood plasma progesterone(AGEP4),which generally coincides with onset of puberty,as an example *** We produced AGEP4 phenotypes from three blood samples collected at about 30-day intervals from approximately 5,000 Holstein–Friesian or Holstein–Friesian×Jersey cross-bred dairy heifers managed in 54 seasonal-calving,pasture-based herds in New *** used these actual data to simulate 7 different visit scenarios,increasing the extent of censoring by disregarding data from one or two of the three *** methods for deriving phenotypes from these data were explored:1)ordinal categorical variables which were analysed using categorical threshold analysis;2)continuous variables,with a penalty of 31 d assigned to right-censored phenotypes;and 3)continuous variables,sampled from within a lower and upper bound using a data augmentation *** Credibility intervals for heritability estimations overlapped across all methods and visit scenarios,but estimated heritabilities tended to be higher when left censoring was *** sires with at least 5 daughters,the correlations between estimated breeding values(EBVs)from our three-visit scenario and each reduced data scenario varied by method,ranging from 0.65 to *** estimated breed effects also varied by method,but breed differences were smaller as phenotype censoring *** Our results indicate that using

关键词： Cattle Gibbs sampler markov-chain monte Carlo(mCmC) Puberty

Alcohol metabolites and lipopolysaccharide: Roles in the development and/or progression of alcoholic liver disease

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World Journal of Gastroenterology 2009年第10期15卷 1209-1218页

作者： Courtney S Schaffert michael J duryee Carlos d Hunter Bartlett C hamilton 3rd Amy L deVeney mary m Huerter Lynell W Klassen Geoffrey m Thiele department of Internal medicine University of Nebraska Medical Center 986350 Nebraska Medical Center Omaha NE 68198-6350 United States Veterans Administration Alcohol Research Center Omaha Veterans Administration Medical Center 4101 Woolworth Avenue Omaha NE 68105 United States department of Pathology and microbiology University of Nebraska Medical Center 986495 Nebraska Medical Center Omaha NE 68198-6495 United States

The onset of alcoholic liver disease (ALd) is initiated by different cell types in the liver and a number of different factors including: products derived from ethanol-induced inflammation, ethanol metabolites, and the indirect reactions from those metabolites. Ethanol oxidation results in the production of metabolites that have been shown to bind and form protein adducts, and to increase inflammatory, fibrotic and cirrhotic responses. Lipopolysaccharide (LPS) has many deleterious effects and plays a significant role in a number of disease processes by increasing inflammatory cytokine release. In ALd, LPS is thought to be derived from a breakdown in the intestinal wall enabling LPS from resident gut bacterial cell walls to leak into the blood stream. The ability of adducts and LPS to independently stimulate the various cells of the liver provides for a two-hit mechanism by which various biological responses are induced and result in liver injury. Therefore, the purpose of this article is to evaluate the effects of a two-hit combination of ethanol metabolites and LPS on the cells of the liver to increase inflamma-tion and fi brosis, and play a role in the development and/or progression of ALd.

关键词：酒精性肝病代谢物脂多糖细胞因子释放肝脏炎症生物反应代谢产物蛋白质结合

The strain rate sensitive and anisotropic behavior of rare-earth magnesium alloy ZEK100 sheet

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Journal of magnesium and Alloys 2023年第3期11卷 882-891页

作者： H.Wang X.Sun S.Kurukuri m.J.Worswick d.Y.Li Y.H.Peng P.d.Wu State Key Laboratory of mechanical Systems and Vibration Shanghai Jiao Tong UniversityShanghai 200240China materials Genome Initiative Center Shanghai Jiao Tong UniversityShanghai 200240China department of mechanical and mechatronics Engineering University of WaterlooWaterlooOntario N2L 3G1Canada department of mechanical Engineering Mc Master UniversityHamiltonOntario L8S 4L7Canada

To overcome the limitation in formability at room temperature,manufacturers have developed magnesium alloys with remarkable properties by adding rare-earth *** rare-earth magnesium alloys behave differently from the conventional alloys,especially with respect to their coupled anisotropic and strain rate sensitive *** the current work,such behavior of the rare-earth mg alloy ZEK100 sheet at room temperature is investigated with the aid of the elastic viscoplastic self-consistent polycrystal plasticity *** strain rate sensitivities(SRSs)for various deformation modes are employed by the model to simulate the strain rate sensitive behaviors under different loading directions and loading *** agreement between the experiments and simulations reveals the importance and necessity of using different SRSs for each deformation mode in hexagonal close-packed ***,the relative activities of each deformation mode and the texture evolution during different loadings are *** anisotropic and strain rate sensitive behavior is ascribed to the various operating deformation modes with different SRSs during loading along different directions.

关键词： Rare-earth magnesium alloy Strain rate sensitivity Twinning Crystal plasticity

developing targets for radiation transport experiments at the Omega laser facility

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High Power Laser Science and Engineering 2017年第3期5卷 1-4页

作者： d.Capelli C.A.Charsley-Groffman R.B.Randolph d.W.Schmidt T.Cardenas F.Fierro G.Rivera C.hamilton J.d.Hager H.m.Johns N.E.Lanier J.L.Kline Los Alamos National Laboratory

Targets have been developed to measure supersonic radiation transport in aerogel foams using absorption *** target consists of an aerogel foam uniformly doped with either titanium or scandium inserted into an undoped aerogel foam package. This creates a localized doped foam region to provide spatial resolution for the *** and characterization of the foams is a key challenge in addition to machining and assembling the two foams so they mate without gaps. The foam package is inserted into a beryllium sleeve and mounted on a gold *** target is mounted to a holder created using additive manufacturing and mounted on a stalk. The manufacturing of the components, along with assembly and metrology of the target are described here.

关键词： absorption spectroscopy doped foams radiation transport

Apparent redox potential discontinuity(aRPd) depth as a relative measure of sediment oxygen content and habitat quality

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International Journal of Sediment Research 2015年第1期30卷 74-80页

作者： Travis G.GERWING Alyssa m.ALLEN GERWING diana J.hamilton myriam A.BARBEAU department of Biology University of New Brunswick department of Biology Mount Allison University

As hypoxic conditions spread in our oceans,indices that quickly and efficiently assess oxygen content in sediment pore water,and habitat quality are increasingly becoming *** to the apparent redox potential discontinuity(aRPd) in sediment is one such index;however,the relationship between aRPd depth and oxygen content is still *** quantified oxygen content in sediment pore water with a dissolved oxygen(dO) probe,utilizing luminescent technology,to determine how dO concentration varies with depth in the sediment,and with position relative to the aRPd(above versus below) on an intertidal mudflat in the Bay of Fundy,*** on generalized linear regression models,we found that depth in the sediment was a poor predictor of pore water dO concentration,while position in the sediment relative to the aRPd was a good ***,sediment above the aRPd had higher dO content than sediment *** maintain that aRPd depth is a good measure of relative oxygen content in sediment pore water,as well as habitat ***,we recommend caution as the factors that influence aRPd depth arc numerous and variable;therefore,the relationship between aRPd depth and dO content should be experimentally confirmed in any system of interest before aRPd depth is used as an indicator.

关键词： Anoxia Apparent redox potential discontinuity(aRPd) dissolved oxygen Habitat quality Hypoxia Intertidal marine benthos Sediment pore water.

Vibration and Buckling Analyses of Sandwich Plates Containing Functionally Graded metal Foam Core

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Acta mechanica Solida Sinica 2022年第4期35卷 587-602页

作者： A.Garg H.d.Chalak L.Li m.-O.Belarbi R.Sahoo T.mukhopadhyay department of Civil Engineering National Institute of TechnologyKurukshetraHaryana136119India department of Aerospace Engineering Indian Institute of TechnologyKanpurUttar Pradesh208016India State Key Lab of digital manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Laboratoire de Génie Energétique et matériaux LGEMFacultéde la science et de lo TechnologieUniversitéde BiskraB.P.145R.P.07000BiskraAlgeria department of Civil Engineering Indian Institute of TechnologyBanaras Hindu UniversityVaranasiUttar Pradesh221005India

In the present work,free vibration and buckling analyses of sandwich plates with various functionally graded foam cores are carried *** cores are assumed to be made of metal,and three different configurations of the porous distribution in the core layer are taken into *** carry out a comparative study between the distributions of pores in the core foam,the mass of foam in all three cases is kept the *** vibration and buckling behaviors of skew plates are also analyzed as a part of the current *** principle of minimization of potential energy and.hamilton’s principle are used for the derivation of the governing equations,while a C-0 finite element-based higher-order zigzag formulation is developed to solve the free vibration and buckling *** influences of gradation laws,boundary conditions,skew angle and geometry of plates are studied in detail for the dynamic and stability *** is found that both the non-dimensional natural frequency and buckling load decrease with the increase in the thickness of the metal foam cores,while they show an increasing trend as the skew angle of the plate increases.

关键词： Sandwich plate metal foam core Functionally graded core Finite element Skew plate

An Iterative Relaxation Approach to the Solution of the hamilton-Jacobi-Bellman-Isaacs Equation in Nonlinear Optimal Control

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 360-366页

作者： m.d.S.Aliyu department of Electrical Engineering King Faisal University Al-Ahsa 31982 Saudi Arabia IEEE

In this paper, we propose an iterative relaxation method for solving the hamilton-Jacobi-Bellman-Isaacs equation(HJBIE) arising in deterministic optimal control of affine nonlinear systems. Local convergence of the method is established under fairly mild assumptions, and examples are solved to demonstrate the effectiveness of the method. An extension of the approach to Lyapunov equations is also discussed. The preliminary results presented are promising, and it is hoped that the approach will ultimately develop into an efficient computational tool for solving the HJBIEs.

关键词： Affine nonlinear system bounded continuous function convergence hamilton-Jacobi-Bellman-Isaacs equation Lyapunov equation relaxation method Riccati equation