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Examining the effect of the aging state on strength and plasticity of wrought aluminum alloys

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journal of Materials Science & Technology 2022年第27期122卷 54-67页

作者： Z.Qu Z.j.Zhang j.X.Yan P.Zhang B.S.Gong S.L.Lu Z.F.Zhang T.G.Langdon Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Department of Mechanical Engineering University of SouthamptonSouthampton SO171BJUnited Kingdom

A general rule of strength and plasticity was proposed for three typical wrought Al alloys(2xxx,6xxx,and 7xxx)subjected to different aging *** of the work-hardening processes and dislocation configurations in tensile and compressive testing reveal that this general rule arises because there is a common mechanism for these three kinds of wrought alloys whereby the tendency for cross-slip increases monotonously with aging *** analyzing the strain hardening exponent and the stacking fault energy,it is demonstrated that the change in the dislocation slip mode is attributed mainly to the formation of second phases rather than to the matrix ***,a new work-hardening model was proposed for wrought Al alloys containing second phases and this explains the interaction between dislocations and second phases and other relevant experimental *** work is therefore beneficial for quantitatively investigating and optimizing the strength and plasticity of wrought aluminum alloys.

关键词： Wrought aluminum alloy Strength and plasticity Work hardening Dislocation slip mode Second phase

Mechanically durable,super-repellent 3D printed microcell/nanoparticle surfaces

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Nano Research 2022年第6期15卷 5678-5686页

作者： Sajad Haghanifar Anthony j Galante Mehdi Zarei jun Chen Susheng Tan Paul W Leu Department of Industrial Engineering University of PittsburghPittsburghPA 15261USA Department of Mechanical Engineering and Materials Science University of PittsburghPittsburghPA 15261USA Department of Electrical and Computer Engineering and Peterson Institute of NanoScience and Engineering University of PittsburghPittsburghPA 15261USA Department of Chemical Engineering University of PittsburghPittsburghPA 15261USA

Three-dimensional(3D)printed re-entrant micropillars have demonstrated high static contact angles for an unprecedented variety of liquids,but have yet to achieve this with low contact angle hysteresis and excellent abrasion *** report on the demonstration of 3D printed microcell/nanoparticle structures that exhibit high static contact angle,low contact angle hysteresis,and high mechanical *** and microcells both exhibit high static contact angles with water and ethylene glycol(EG),but suffer from high contact angle hysteresis,indicative of rose petal *** modeling results indicate that micropillars are able to achieve higher static contact angle and breakthrough pressure simultaneously compared with ***,simulations also indicate that micropillars have higher maximum equivalent stress at their bases,so that they are more prone to mechanical *** address contact angle hysteresis and mechanical durability issues by the creation of 3D printed microcell/nanoparticle arrays that demonstrate super-repellency and retain their super-repellency after 100 cycles of mechanical abrasion with a Scotch-Brite abrasive pad under a pressure of 1.2 *** use of interconnected microcell structures as opposed to micropillars addresses mechanical durability *** contact angle hysteresis is realized by coating 3D printed structures with low surface energy nanoparticles,which lowers the solid–liquid contact area *** results demonstrate new 3D printed structures with mechanical durability and super-repellency through the use of microcell structures integrated with fluorinated nanoparticles.

关键词： superomniphobicity three-dimensional(3D)printing surface evolver mechanical durability microcell re-entrant micropillar

Visualising the heart of chaos

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Light(Science & Applications) 2021年第12期10卷 2256-2257页

作者： Nicholas j.Lambert Harald G.L.Schwefel Department of Physics University of OtagoDunedinNew Zealand The Dodd-Walls Centre for Photonic and Quantum Technologies DunedinNew Zealand

The intra-cavity electro-magnetic field distribution in a microdisk resonator can be visualised by inducing a phase shift via a scanning probe beam.

关键词： resonator chaos Visual

A good gut feeling on Sarm1-mediated axon degeneration

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Protein & Cell 2021年第8期12卷 596-598页

作者： Victoria E.von Saucken David j.Simon Department of Biochemistry Weill Cornell Medical College Tri-Institutional MD-Ph D Program Weill Cornell Medicine Rockefeller University Memorial Sloan Kettering Cancer Center

Axons,the cable-l ike projections of neurons,experience a wide range of stressors throughout their *** result of any one of these challenges can be catastrophic,promoting degeneration of the *** degeneration is an active signaling process observed in traumatic brain injury,chemotherapy-induced peripheral neuropathies,and neurodegen erative disease (Simon and Watkins,2018;Coleman and Hoeke,2020).As a result,tremendous efforts have been made to identify biological targets that can be harnessed to block axon degeneration to treat these *** promising candidate is Sarm1 (sterile alpha and TIR motif containing protein 1),a member of the Myd88 immune adaptor protein family that itself has no clear role in innate immunity.

关键词： SARM1 ACTIVATION TRIGGERS DEATH

Qualifying the suitability of living donor livers for pediatric liver transplantation:are we doing the right thing?

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Hepatobiliary Surgery and Nutrition 2023年第3期12卷 462-464页

作者： Henkjan j.Verkade Frans C.j.Cuperus Aad P.van den Berg Division of Pediatric Gastroenterology and Hepatology Department of PediatricsUniversity of GroningenBeatrix Children’s HospitalUniversity Medical Center GroningenGroningenThe Netherlands Department of Gastroenterology and Hepatology University of GroningenUniversity Medical Center GroningenGroningenThe Netherlands

Over the last decades,liver transplantation has become the standard care for many forms of end-stage liver disease,both in adults and in *** prognosis after pediatric liver transplantation(pLT)has steadily increased up to a patient survival at 5 years of 85%and an estimated graft half life of 31 years(1,2).In the early days of pLT,the transplanted organ originated from deceased *** 1990,adult-to-child living donor liver transplantation(LDLT)programs have developed,which rapidly gained popularity,particularly in Europe and Asia(2,3).A major stimulus for LDLT has been the limited availability of deceased *** indications for liver transplantation have expanded,particularly for adult patients,at a higher rate than the availability of donor ***,the quality of donor organs has steadily declined,resulting in a decreased utilization of livers from deceased donors for transplantation(4).The limited availability of qualified deceased donor livers has further stimulated LDLT:in Europe,for example,the percentage of living donor organs used for pLT increased from 7%before 2000 to 40%since 2010(1).

关键词： Steatosis graft survival pediatric liver transplantation(pLT) patient survival

Carbon deficiency introduced plasticity of rock-salt-structured transition metal carbides

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journal of Materials Science & Technology 2023年第33期164卷 205-214页

作者： Buhao Zhang Youwei Wang jie Yin Yichen Wang Hangfeng Zhang Tamás Csanádi ján Dusza Michael j.Reece Nan Lin Xiao Yang Xuejian Liu Zhengren Huang Dongliang jiang State Key Laboratory of High-Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Faculty of Engineering University of NottinghamNottinghamNG7 2RDUnited Kingdom School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon E1 4NSUK Institute of Materials Research Slovak Academy of SciencesWatsonova 4704353KošiceSlovak Republic College of Materials Science and Engineering Hunan UniversityChangsha410082China

High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection ***,the intrinsic brittleness of TMC ceramics impedes their performance in aerodynamically harsh *** this work,a promising strategy is proposed to introduce plasticity in TaC–HfC solid solutions by manipulating carbon *** approach combines density-functional theory(DFT)with experiments and takes Pugh's ratio(k)as the *** of carbon atoms in TaC–HfC solid solutions results in the de-localizing of valence electrons,deviation of spatial modulus along different crystal plane directions,and leading to significant elastic *** carbon deficient Ta_(0.8)Hf_(0.2)C_(0.8) is predicted to be a‘softer phase’with reduced modulus and Pugh's ratio(k=0.58).A series of Ta1–xHfxCy(x=0.2 and 0.8,y=0.8,0.9,and 1.0)bulk ceramics are experimentally fabricated by an excessive metal alloying *** and hexagonal close-packed structured carbides are derived when the carbon deficiency y decreased to *** indentation modulus drops from 641.8±14.8 GPa for Ta_(0.8)Hf_(0.2)C_(1.0) to 555.8±9.9 GPa for *** specific stoichiometric composition of Ta_(0.8)Hf_(0.2)C_(0.8) is experimentally verified to possess both plasticity(k=0.41)and ultra-high nanohardness(41.3±1.3 GPa).

关键词： Brittle Plasticity Transitional metal carbides Pugh's ratio Carbon deficiency

Endoscopic Management of Pediatric Cholesteatoma

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journal of Otology 2020年第1期15卷 17-26页

作者： Peter j.Ryan Nirmal P.Patel Department of Otolaryngology and Head and Neck Surgery Royal North Shore HospitalSt LeonardsNSWAustralia Kolling Deafness Research Centre Macquarie University and University of SydneyNSWAustralia

Pediatric cholesteatoma occurs in one of two forms:congenital cholesteatoma,developing from embryonic epidermal cell rests or acquired cholesteatoma,associated with a focal defect in the tympanic *** disease has been traditionally managed with the operating microscope,often requiring mastoidectomy for adequate visualization of and access to the middle ear and mastoid ***,advances in endoscopic equipment have enabled otologists to manage most cases of pediatric cholesteatoma via a minimally-invasive,transcanal endoscopic *** review discusses the current literature relating to the etiopathogenesis,assessment and endoscopic management of pediatric *** outcomes of endoscopic treatment,emerging trends and technologies are also reviewed.

关键词： Cholesteatoma Pediatric Endoscopic Minimally-invasive Middle ear Mastoid

Effects of mechanical vibration on the physical,metallurgical and mechanical properties of cast A308(LM21)aluminum alloy

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International journal of Minerals,Metallurgy and Materials 2022年第6期29卷 1206-1215页

作者： Siddharth Yadav S.P.Tewari j.K.Singh S.C.Ram Department of Mechanical Engineering Indian Institute of Technology(BHU)Varanasi 221005India Department of Metallurgical Engineering Indian Institute of Technology(BHU)Varanasi 221005India

This study investigated the microstructure,physical,and mechanical properties of die-cast A308 alloy subjected to mechanical vibration during *** frequencies(0,20,30,40,and 50 Hz)at constant amplitude(31μm)were employed using a power amplifier as the power input device.X-ray diffraction,optical microscopy,and scanning electron microscopy were used to examine the morphological changes in the cast samples under stationary and vibratory *** features of the castings were evaluated using Image j *** average values of metallurgical features,including primaryα-Al grain size,dendrite arm spacing,average area of eutectic silicon,aspect ratio,and percentage porosity,reduced by 34%,59%,56%,22%,and 62%,respectively,at 30 Hz frequency compared with stationary *** tests of the cast samples showed that the yield strength(YS),ultimate tensile strength(UTS),percentage elongation(%EL),and microhardness(HV)increased by 8%,13%,17%,and 16%,respectively,at 30 Hz frequency compared with stationary *** fractured surface of the tensile specimens exhibited mixed-mode fracture behavior because of brittle facets,cleavage facets,ductile tearing,and dimple *** presence of small dimples showed that plastic deformation occurred before fracture.

关键词： mechanical vibration microstructures microhardness tensile strength fractography

Localized space-tim e method of fundamental solutions for three-dimensional transient diffusion problem

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Acta Mechanica Sinica 2020年第5期36卷 1051-1057,I0002页

作者： L.Qiu j.Lin Q.-H.Qin W.Chen International Center for Simulation Software in Engineering and Sciences College of Mechanics and MaterialsHohai UniversityNanjing 210098China College of Engineering and Computer Science Australian National UniversityCanberraACT 2601Australia State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Acoustic Institute of AcousticsChinese Academy of SciencesBeijing 100190China

A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this *** interval segmentation in temporal direction is developed for the accurate simulation of long-time-dependent diffusion *** the LSTMFS,the whole space-time domain with nodes arranged i divided into a series of overlapping subdomains with a simple *** each subdomain,the conventional method of fundamental solutions is utilized and the coefficients associated with the considered domain can be explicitly *** calculating a combined sparse matrix system,the value at any node inside the space-time domain can be *** experi-ments demonstrate that high accuracy and efficiency can be simultaneously achieved via the LSTMFS,even for the problems defined on a long-time and quite complex computational domain.

关键词： Localized spacetime method of fundamental solutions Meshless method Long-time evolution Transient diffusion