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Crystallization and impact history of a meteoritic sample of early lunar crust(NWA 3163)refined by atom probe geochronology

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Geoscience Frontiers 2019年第5期10卷 1841-1848页

作者： l.F. White D.E. Moser K.T. Tait B. langelier i. Barker j.R. Darling Centre for Applied Planetary Mineralogy Department of Natural HistoryRoyal Ontario MuseumTorontoOntarioM5S 2C6Canada Department of Earth Sciences University of TorontoTorontoOntarioM5S 3B1Canada Department of Earth Sciences University of Western OntarioLondonN6A 5B7Canada Canadian Centre for Electron Microscopy McMaster UniversityHamiltonOntarioCanada School of Earth and Environmental Science University of PortsmouthPortsmouthUK

Granulitic lunar meteorites offer rare insights into the timing and nature of igneous,metamorphic and impact processes in the lunar *** dating the different events recorded by these materials is very challenging,however,due to low trace element abundances (***,Nd,lu,Hf),rare micrometerscale U-Th-bearing accessory minerals,and disturbed Ar-Ar systematics following a multi-stage history of shock and thermal *** we report on micro-baddeleyite grains in granulitic mafic breccia NWA 3163 for the first time and show that targeted microstructural analysis (electron backscatter diffraction) and nanoscale geochronology (atom probe tomography) can overcome these barriers to lunar chronology.A twinned (-90°/) baddeleyite domain yields a 232Th/208Pb age of 4328 ± 309 Ma,which overlaps with a robust secondary ion mass spectrometry (SiMS) 207Pb/206Pb age of 4308± 18.6 Ma and is interpreted here as the crystallization age for the igneous protolith of NWA 3163.A second microstructural domain,in width,contains patchy overprinting baddeleyite and yields a Th-Pb age of 2175± 143 Ma,interpreted as dating the last substantial impact event to affect the *** finding demonstrates the potential of combining microstructural characterization with nanoscale geochronology when resolving complex P-T-t histories in planetary materials,here yielding the oldest measured crystallization age for components of lunar granulite NWA 3163 and placing further constraints on the formation and evolution of lunar crust.

关键词： Baddeleyite U-Th-Pb isotopes EBSD Atom probe tomography Geochronology Northwest Africa 3163

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Boundary discontinuous Fourier analysis of thick beams with clamped and simply supported edges via CUF

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Chinese journal of Aeronautics 2017年第5期30卷 1708-1718页

作者： F.G.CANAlES j.l.MANTARi Faculty of Mechanical Engineering Universidad de Ingenieriay Tecnologia ( UTEC) Lima 15063 Peru Department of Mechanical Engineering University of New Mexieo Albuquerque 87131 USA

This paper presents an analytical solution for static analysis of thick rectangular beams with different boundary conditions. Carrera＇s Unified Formulation（CUF） is used in order to consider shear deformation theories of arbitrary order. The novelty of the present work is that a boundary discontinuous Fourier approach is used to consider clamped boundary conditions in the analytical solution, unlike Navier-type solutions which are restricted to simply supported *** equations are obtained by employing the principle of virtual work. The numerical accuracy of results is ascertained by studying the convergence of the solution and comparing the results to those of a 3D finite element solution. Beams subjected to bending due to a uniform pressure load and subjected to torsion due to opposite linear forces are considered. Overall, accurate results close to those of 3D finite element solutions are obtained, which can be used to validate finite element results or other approximate methods.

关键词： Analytical solution Beam Clamped Fourier Unified formulation

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Speeding up transmissions of unknown quantum information along ising-type quantum channels

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Chinese Physics B 2017年第1期26卷 125-130页

作者： W j Guo l F Wei Quantum Optoelectronics laboratory Southwest Jiaotong University Chengdu 610031 China State Key laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat-Sen University Guangzhou 510275 China

Quantum teleportation with entanglement channels and a series of two-qubit SWAP gates between the nearestneighbor qubits are usually utilized to achieve the transfers of unknown quantum state from the sender to the distant receiver. in this paper, by simplifying the usual SWAP gates we propose an approach to speed up the transmissions of unknown quantum information, specifically including the single-qubit unknown state and two-qubit unknown entangled ones,by a series of entangling and disentangling operations between the remote qubits with distant interactions. The generic proposal is demonstrated specifically with experimentally-existing ising-type quantum channels without transverse interaction; liquid NMR-molecules driven by global radio frequency electromagnetic pulses and capacitively-coupled josephson circuits driven by local microwave pulses. The proposal should be particularly useful to set up the connections between the distant qubits in a chip of quantum computing.

关键词： unknown quantum information transfers ising-type quantum chains NMR molecules superconducting circuits

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Floor dust erosion during early stages of coal dust explosion development

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international journal of Mining Science and Technology 2019年第6期29卷 825-830页

作者： Marcia l.Harris Michael j.Sapko Center for Disease Control and Prevention (CDC) National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD)

An ignition of methane and air can generate enough air flow to raise mixtures of combustible coal and rock *** expanding high temperature combustion products ignite the suspended dust mixture and will continue to propagate following the available combustible fuel *** the concentration of the dispersed rock dust is sufficient,the flame will stop ***-scale explosion tests were conducted within the National institute for Occupational Safety and Health(NiOSH)lake lynn Experimental Mine(llEM)to measure the dynamic pressure history and the post-explosion dust scour *** aim of this effort is to provide quantitative data on depth of dust removal during the early stages of explosion development and its relationship to the depth of floor dust collected for assessing the incombustible content most likely to participate in the combustion *** experimental work on dust removal on is not only important for coal mine safety but also for industrial dust explosions.

关键词： Underground Coal dust Explosion Dust sampling

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Vibrational behavior of isotropic plate structures in contact with a bounded fluid via unified formulation

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Chinese journal of Aeronautics 2019年第4期32卷 921-937页

作者： F.G.CANAlES j.l.MANTARi Faculty of Mechanical Engineering Instituto de Investigación en Ingeniería Naval(IDIIN)Universidad Nacional de Ingenieria(UNI) Department of Mechanical Engineering University of New Mexico

This paper presents an analytical solution for free vibration analysis of thick rectangular isotropic plates coupled with a bounded fluid for various boundary conditions. in order to consider displacement theories of an arbitrary order, the Carrera Unified Formulation(CUF) is used. The eigenvalue problem is obtained by using the energy functional, considering plate and fluid kinetic energies as well as the potential energy of the plate. The Ritz method is used to evaluate the displacement variables, and the functions used in the Ritz series can be adjusted to consider any of the classical boundary conditions. The convergence of the solution is analyzed, and a validation of results considering open literature and 3D finite element software is performed. Parametric studies are carried out to obtain natural frequencies as a function of the side-to-thickness ratio, plate aspect ratio, fluid domain size, plate boundary conditions, and fluid-solid density ratio. Pressure and velocity in the fluid domain are evaluated in order to establish the consistency of the *** results for thick plates are obtained with a much lower computational cost compared to that of 3D finite element solutions.

关键词： Added mass Fluid-structure interaction Plate Ritz method Unified formulation Vibration

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An analytical model for electrode-ceramic interaction in multilayer piezoelectric actuators

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Acta Mechanica Sinica 2007年第2期23卷 199-208页

作者： B.l.Wang j.C.Han Center for Composite Materials Harbin Institute of TechnologyHarbin 150001China

The present paper develops an analytical model for multi-electrodes in multi-layered piezoelectric actuators, in which the electrodes are vertical to and terminated at the edges of the medium and electroelastic field concentrations ahead of the electrodes in the multilayer piezoelectric actuators are examined. By considering a representative unit in realistic multilayers, the problem is formulated in terms of electric potential between the electrode tips and results in a system of singular integral equations in which the electric potential is taken as unknown function. Effects are investigated of electrode spacing and piezoelectric coupling on the singular electroelastic fields at the electrode tips, and closed-form expressions are given for the electromechanical field near the electrode tips. Exact solution for un-coupled dielectrics is provided, where no piezoelectric coupling is present.

关键词： Actuators . Piezoelectric materials . Electrodes. Multilayer. Fracture mechanics

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Deformation behaviors of Cu bicrystals with an inclined twin boundary at multiple scales

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journal of Materials Science & Technology 2017年第7期33卷 698-702页

作者： l.l.li Z.j.Zhang P.Zhang j.Tan j.B.Yang Z.F.Zhang Shenyaag National laboratory for Materials Science lastitute of Metal Research Chinese Academy of Sciences Shenyaag 110016 China

Cu bicrystals of different sizes with a sole twin boundary（TB） inclined at 45？with respect to the loading direction were deformed under unidirectional and cyclic loading, respectively. it is found that the slip bands（SBs） parallel to the TB can be activated near the TB at all scales without obeying the Schmid＇s *** is concerned with the local stress enhancement in the macroscale while it is more closely related to the scarce dislocation sources in the microscale. Moreover, a wedge-shaped zone formed near the TB in the microscale ascribed to the limited specimen size.

关键词： Bicrystal Micropillar Twin boundary Schmid factors Size effect

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The relationship between anogenital distance and the androgen receptor CAG repeat length

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Asian journal of Andrology 2013年第2期15卷 286-289,I0010页

作者： Michael l Eisenberg Tung-Chin Hsieh Alexander W Pastuszak Matthew G Mcintyre Rustin C Waiters Dolores j lamb larry i lipshultz Department of Urology Stanford University School of Medicine Stanford CA 94305 USA Department of Urology Baylor College of Medicine Houston TX 77030 USA

Anogenital distance （AGD） is used to define degree of virilization of genital development, with shorter length being associated with feminization and male infertility. The first exon of the androgen receptor （AR） consists of a polymorphic sequence of cytosine-adenineguanine （CAG） repeats, with longer CAG repeat lengths being associated with decreased receptor function. We sought to determine if there is an association between AGD and AR CAG repeat length. A cross-sectional, prospective cohort of men evaluated at a urology clinic at a single institution was recruited. AGD （the distance from the posterior scrotum to the anal verge） and penile length （Pl） were measured. Sanger DNA sequence analysis was used to define CAG repeat length. AGD and CAG repeat lengths in 195 men were determined. On unadjusted analysis, there was no linear relationship between CAG repeat length and Pl （P=0.17） or AGD （P=-0.31）. However, on sub-population analyses, those men with longer CAG repeat lengths （〉26） had significantly shorter AGDs compared to men with shorter CAG repeat lengths. For example, the mean AGD was 41.9 vs. 32.4 mm with a CAG repeat length ≤26 vs. 〉26 （P=0.01）. in addition, when stratifying the cohort based on AGD, those with AGD less than the median （i.e. 40 mm） had a longer CAG repeat length compared to men with an AGD 〉40 mm （P=-0.02）. in summary, no linear relationship was found between AGD and AR CAG repeat length overall.

关键词： androgen receptor (AR) anogenital distance (AGD) genitalia penile length (Pl) perineum

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Electrolytic deposition of super-smart composite coating of Zn-V2O5-NbO2 on low carbon steel for defence application

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Defence Technology（防务技术） 2018年第5期14卷 446-450页

作者： O.S.i.Fayomi l.R.Kanyane A.P.i.Popoola S.O.Oyedepo Department of Chemical Metallurgical and Materials EngineeringTshwane University of TechnologyP.M.B.X680PretoriaSouth Africa Department of Mechanical Engineering Covenant UniversityP.M.B 1023OtaNigeria

Despite the massive usages of low carbon steel in automobile for engineering components, its corrosion and high friction coefficient in aggressive environment make it limited in service. This paper is aimed at modifying low carbon steel structural component with thin film composite for enhanced mechanical and corrosion properties. The steel structure was electrodeposited with Zn-V_2 O_5 and embedded with varied NbO_2 weight concentration of 6-12 wt % based electrolyte. Scanning electron microscope(SEM) and high optical microscope was used to study the microstructural evolution of the fabricated coatings. The thermal stability of the fabricated coatings was studied in an isothermal furnace at 300 ℃ and 600 ℃ and further characterized using a high tech optical microscope. Potentiodynamic polarization technique was used to investigate the corrosion behavior of the composites in 3.65% NaCl. From the result, the effect of NbO_2 on Zn-V_2 O_5-NbO_2 was massive with improved crystal grain within the coatings lattices. The coating possesses strong metallurgical bonding and good corrosion resistance properties of about 0.315 mm/yr corrosion rate compare to 4.1 mm/yr of as-received sample. No doubt the impact of thermal shock on the resilient characteristics of the composite coating was moderate owing to the stable adherent properties of the deposited coatings.

关键词： Electrodeposition low carbon steel Micro-hardness Thermal stability corrosion behavior Rare earth metal(REM)

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Tailored surface textures to increase friction-A review

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Friction 2022年第9期10卷 1285-1304页

作者： Henara l.COSTA jörg SCHillE Andreas ROSENKRANZ School of Engineering Surface Engineering GroupUniversidade Federal do Rio GrandeRio Grande 96203900Brazil University of Applied Sciences Mittweida Laserinstitut Hochschule Mittweida 09648Germany Department of Chemical Engineering Biotechnology and MaterialsUniversity of ChileSantiago 8370459Chile

Surface textures with micro-scale feature dimensions still hold great potential to enhance the frictional performance of tribological *** from the ability of surface texturing to reduce friction,surface textures can also be used to intentionally increase friction in various applications that rely on friction for their adequate ***,this review aims at presenting the state-of-the-art regarding textured surfaces for high-friction *** a brief general introduction,the recent trends and future paths in laser surface texturing are ***,the potential of surface textures to increase friction in different applications including adhesion,movement transmission and control,biomimetic applications,and road-tire contacts is critically *** emphasis in this section is laid on the involved mechanisms responsible for friction ***,current short-comings and future research directions are pointed out thus emphasizing the great potential of(laser-based)surface texturing methods for innovations in modern surface engineering.

关键词： surface texturing tribology laser processing friction increase

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