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Study on the early surface films formed on Mg-Y molten alloy in different atmospheres

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journal of Magnesium and Alloys 2015年第3期3卷 173-179页

作者： A.R.Mirak C.j.Davidson j.A.taylor CAST CRC School of Mechanical and Mining EngineeringThe University of QueenslandBrisbaneQLD 4072Australia CAST CRC CSIRO Materials Science and EngineeringP.O.Box 883KenmoreQLD 4069Australia

In the present study,the non-isothermal early stages of surface oxidation of liquid Mg-1%Y alloy during casting were studied under UPH argon,dry air,and air mixed with protective fluorine-bearing *** chemistry and morphology of the surface films were characterized by SeM and eDX *** results indicate a layer of smooth and tightly coherent oxidation film composed of MgO and Y_(2)O_(3) formed on the molten Mg-Y alloy surface with 40-60 nm thickness under dry air.A dendritic/cellular microstructure is clearly visible with Y-rich second phases gathered in surface of the melt and precipitated along the grain/cell boundaries under all gas *** fluorine-bearing gas mixtures,the surface film was a mixed oxide and fluoride and more even;a flat and folded morphology can be seen under SF6 with oxide as dominated phase and under 1,1,1,2-tetra-fluoroethane,a smooth and compact surface film uniformly covering the inner surface of the bubble with equal oxide and fluoride thickness,which results in a film without any major ***_(2) phase appears to be the key characteristic of a good protective film.

关键词： Mg-Y alloy SeM eDX early surface film Oxidation Fluoridation

Impact of rewilding,species introductions and climate change on the structure and function of the Yukon boreal forest ecosystem

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Integrative Zoology 2018年第2期13卷 123-138页

作者： Rudy BOONSTRA Stan BOUTIN Thomas S.jUNG Charles j.KReBS Shawn taylor Department of Biological Sciences University of Toronto ScarboroughTorontoOntarioCanada Department of Biological Sciences University of AlbertaEdmontonAlbertaCanada Department of environment Government of YukonWhitehorseYukonCanada Department of Zoology University of British ColumbiaVancouverBritish ColumbiaCanada

Community and ecosystem changes are happening in the pristine boreal forest ecosystem of the Yukon for 2 ***,climate change is affecting the abiotic environment(temperature,rainfall and growing season)and driving changes in plant productivity and predator-prey ***,simultaneously change is occurring because of mammal species reintroductions and *** key ecological question is the impact these faunal changes will have on trophic *** productivity in the boreal forest is increasing because of climatic warming,but plant species composition is unlikely to change significantly during the next 50-100 *** 9-10-year population cycle of snowshoe hares will persist but could be reduced in amplitude if winter weather increases predator hunting *** rodents have increased in abundance because of increased vegetation *** ground squirrels have disappeared from the forest because of increased predator hunting efficiency associated with shrub *** have occurred for 2 reasons:human reintroductions of large ungulates and natural recolonization of mammals and birds extending their geographic *** deliberate rewilding of wood bison(Bison bison)and elk(Cervus canadensis)has changed the trophic structure of this boreal ecosystem very *** natural range expansion of mountain lions(Puma concolor),mule deer(Odocoileus hemionus)and American marten(Martes americana)should have few ecosystem *** potential changes will require long-term monitoring studies and experiments on a scale we rarely deem *** affected by climate change,species reintroductions and human alteration of habitats cannot remain stable and changes will be critically dependent on food web interactions.

关键词： community stability introduced species population cycles trophic dynamics

Behavioral and neural auditory thresholds in a frog

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Current Zoology 2019年第3期65卷 333-341页

作者： Ryan C.taylor Karin AKRe Walter WILCZYNSKI Michael j.RYAN Department of Integrative Biology University of Texas at Austin Austin TX USA Department of Biological Sciences Salisbury University Salisbury MD USA Smithsonian Tropical Research Institute Balboa Republic of Panama Neuroscience Institute and Center for Behavioral Neuroscience Georgia State University Atlanta GA USA

Vocalizations play a critical role in mate recognition and mate choice in a number of taxa, especially, but not limited to, orthopterans, frogs, and birds. But receivers can only recognize and prefer sounds that they can hear. Thus a fundamental question linking neurobiology and sexual selection asks-what is the threshold for detecting acoustic sexual displays? In this study, we use 3 methods to assess such thresholds in tdngara frogs: behavioral responses, auditory brainstem responsesz and multi unit electrophysiological recordi ngs from the *** show that thresholds are lowest for multiunit recordings (ca. 45 dB SPL), and then for behavioral responses (ca. 61 dB SPL), with auditory brainstem responses exhibiting the highest thresholds (ca. 71 dB SPL). We discuss why these estimates differ and why, as with other studies, it is unlikely that they should be the same. Although all of these studies estimate thresholds they are not measuring the same thresholds;behavioral thresholds are based on signal salienee whereas the 2 neural assays estimate physiological thresholds. All 3 estimates, however, make it clear that to have an appreciation for detection and salienee of acoustic signals we must listen to those signals through the ears of the receivers.

关键词： anurans auditory brainstem responses auditory thresholds mate choice Physalaemus pustulosus signal recog nition thresholds sexual selection tungara frogs vocalizations

Continuous flow synthesis of plasmonic gold patches and nearly-complete nanoshells on polystyrene core particles

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Particuology 2023年第4期75卷 137-150页

作者： Thomas Meincke Robin N.Klupp taylor Institute of Particle Technology Friedrich-Alexander University Erlangen-NürnbergCauerstrasse 491058ErlangenGermany Collaborative Research Center 1411-Design of Particulate Products Friedrich-Alexander University erlangen-Nürnberg Cauerstrasse 391058 Erlangen Germany

We describe the development of a T-mixer based continuous flow process for the coating of 86-500 nm diameter spherical polystyrene particles with thin gold patches by heterogeneous nucleation and *** establishing a suitable flow rate for good mixing and sufficiently uniform product morphology we systematically investigate the main reaction *** reveals a considerable tunability of the patch morphology and,by virtue of the localized surface plasmon resonance of gold,the optical properties of the product *** order to further widen the range of nanostructures accessible by our process,a second T-mixer was *** introduced new gold precursor,leading to further growth of the patches that were formed after the first *** this approach,nearly-complete gold nanoshells could be produced in high yield on both small and large core particles,without the unwanted production of free-standing gold *** to the pronounced optical properties of nearly-complete gold nanoshells on small core particles,we could estimate from electrodynamic sim-ulations the equivalent shell thickness to be as low as 8.6 *** is significantly thinner than can be routinely achieved using the standard seeded growth approach to synthesise gold *** results are therefore highly promising for the gram-scale synthesis of plasmon resonant nanostructures with designed optical properties.

关键词： Continuous flow Core-shell particles Patchy particles Nucleation Diffusion limited growth

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(english edition) 2025年第1期46卷 37-62页

作者： R.A.jAFARI-TALOOKOLAeI H.GHANDVAR e.jUMAeV S.KHATIR T.CUONG-Le School of Mechanical engineering Babol Noshirvani University of Technology Department of Mechanical engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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Decomposing the drivers of residential space cooling energy consumption in eU-28 countries using a panel data approach

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energy and Built environment 2020年第4期1卷 432-442页

作者： Andreas Andreou john Barrett Peter G.taylor Paul e.Brockway Zia Wadud Sustainability Research Institute School of Earth and EnvironmentUniversity of LeedsLeedsLS29JTUK Low Carbon energy Research Group School of Chemical and Process EngineeringUniversity of LeedsLeedsLS29JTUK Spatial Modelling and Dynamics Research Group Institute for Transport StudiesUniversity of LeedsLeedsLS29JTUK

While space cooling currently represents less than 1%of final energy use in the residential sector of the euro-pean Union(eU-28),it was the fastest growing end-use during the 2000-15 period with a mean annual growth rate of 6%per ***,little is known about factors which have driven regional air-conditioning(AC)energy consumption over time,since the literature is limited to cross-sectional studies that lack differentiation between climatic and non-climatic *** projections for the eU’s electricity sector may therefore neglect the potential implications of rapidly growing AC *** develop a novel decomposition framework,which breaks down residential space cooling energy consumption in eU-28 countries into the effect of different components from 2000 to *** is extended to panel data models identifying specific drivers of space cooling’s climate-sensitive ***,we explore scenarios of residential AC energy consumption up to 2050 and evaluate their impact on summer time peak *** diffusion was found to be the key driver of space cooling energy consumption,but this effect was partly counterbalanced by efficiency *** weather influences AC equipment ownership rate in eU-28 households,personal income has a larger marginal *** baseline scenarios,AC diffusion saturates by 2050,while modestly increasing sectoral final energy ***,our range of scenario values for space cooling energy consumption in 2050 exceed the majority of those originat-ing from recently published *** a future renewables-driven electricity system,energy security risks may emerge from a scenario of fast AC up-take in new and renovated buildings,especially for colder european countries where modelled peak cooling electricity demand is shown to outgrow the projected expansion of solar *** findings have important implications for the eU’s strategy to decarbonise energy supply.

关键词： Space cooling AC diffusion Decomposition analysis Panel data model Peak demand

Stress waves propagation in solids under high-speed liquid impact

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Science China(Physics,Mechanics & Astronomy) 2004年第6期47卷 752-766页

作者： j.e.Field Cavendish Laboratory Cambridge UniversityMadingly RoadCambridge CB3 0HEUK

An experiment of impact between 450 m/s water jets and polymethylme- thacrylate (PMMA) materials with complex surface geometry was conducted. The testing surfaces were a corner, step change, surface-breaking notch, inclined surface, etc. Stress waves propagation in the solid such as reflection, interference and diffraction was observed using polarized optics and an Imacon high speed camera (operating at both of 106 and 5×105 framing rates per second, fps). A damage test by the impact of the side jetting of an 850 m/s water jet was also carried out. It was found that stress waves propagation in solids depends not only on the surface geometry but also on the contact situation between liquid and solid. It was shown that the side jetting has sufficient damage potential although its head may consist of finer droplets. The results of this paper are useful to further analyze the dynamic stress state of solids under high-speed liquid impact.

关键词： high-speed liquid/solid impact, stress waves, mechanical property of solid, high-speed photography.

Faulty evidence for superconductivity in ac magnetic susceptibility of sulfur hydride under pressure

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National Science Review 2022年第6期9卷 43-44页

作者： j.e.Hirsch Department of Physics University of California

Sulfur hydride was reported to become superconducting at high pressure and temperature [1]. Posteriorly, Huang and coworkers measured its ac magnetic susceptibility [2], reportedly confirming that finding. According to Semenok and Oganov [3], their work ‘sets a new standard for experimental studies of superconductivity at high pressure’.Instead I argue here that the ac susceptibility measurements of Huang et al.

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examining the“revisability”benefit of hip resurfacing arthroplasty

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World journal of Orthopedics 2024年第6期15卷 554-559页

作者： jose George Adam j taylor Thomas P Schmalzried Department of Orthopedics Harbor UCLA Medical CenterTorranceCA 90509United States

BACKGROUND Hip resurfacing arthroplasty(HRA)is an alternative to total hip arthroplasty(THA)that is typically reserved for young active patients because it preserves ***,the benefits of HRA only hold true if conversion THA after failed HRA provides acceptable *** To compare patient reported outcomes for conversion THA after HRA failure to primary *** A retrospective review of 36 patients(37 hips)that underwent conversion THA for failed HRA between October 2006 and May 2019 by a single surgeon was *** reported outcomes[modified Harris Hip Score(mHHS),University of California Los Angeles(UCLA)activity score]were obtained via an email-based responder-anonymous *** were compared to normative data of a primary THA cohort with similar *** analysis was performed comparing outcomes of conversion THA for adverse local tissue reaction(ALTR)vs all other causes for *** The study group had a lower mHHS than the control group(81.7±13.8 vs 90.2±11.6,Pever,both groups had similar UCLA activity levels(7.5±2.3 vs 7.2±1.6,P=0.51).Patients that underwent conversion for non-ATLR causes had similar mHHS(85.2±11.5 vs 90.2±11.6,P=0.11)and higher UCLA activity levels(8.5±1.8 vs 7.2±1.6,Ped to the control *** that underwent conversion for ATLR had worse mHHS(77.1±14.5 vs 90.2±11.6,Pevels(6.1±2.3 vs 7.2±1.6,P=0.05)when compared to the control *** Patient outcomes equivalent to primary THA can be achieved following HRA conversion to ***,inferior outcomes were demonstrated for ALTR-related HRA *** selection and perhaps further studies examining alternative HRA bearing surfaces should be considered.

关键词： Total hip arthroplasty Hip resurfacing arthroplasty Conversion total hip arthroplasty Adverse local tissue reaction Patient reported outcome measures