1,173 research outputs found
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Multicomponent bulk metallic glasses with elevated-temperature resistance
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Icosahedral and dodecagonal quasicrystal plus glass alloys with plastic deformability
A clinical prediction rule for diagnosing severe acute respiratory syndrome in the emergency department
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Novel Heating-Induced Reversion during Crystallization of Al-based Glassy Alloys.
Thermal stability and crystallization of three multicomponent glassy alloys, Al86Y7Ni5Co1Fe0.5Pd0.5, Al85Y8Ni5Co1Fe0.5Pd0.5 and Al84Y9Ni4Co1.5Fe0.5Pd1, were examined to assess the ability to form the mixture of amorphous (am) and fcc-aluminum (Îą-Al) phases. On heating, the glass transition into the supercooled liquid is shown by the 85Al and 84Al glasses. The crystallization sequences are [am]âââ[amâ+âÎą-Al]âââ[Îą-Alâ+âcompounds] for the 86Al and 85Al alloys, and [am]âââ[amâ+âÎą-Alâ+âcubic AlxMy (Mâ=âY, Ni, Co, Fe, Pd)]âââ[amâ+âÎą-Al]âââ[Îą-Alâ+âAl3Yâ+âAl9(Co, Ni)2â+âunknown phase] for the 84Al alloy. The glass transition appears even for the 85Al alloy where the primary phase is Îą-Al. The heating-induced reversion from [amâ+âÎą-Alâ+âmulticomponent AlxMy] to [amâ+âÎą-Al] for the 84Al alloy is abnormal, not previously observed in crystallization of glassy alloys, and seems to originate from instability of the metastable AlxMy compound, in which significant inhomogeneous strain is caused by the mixture of solute elements. This novel reversion phenomenon is encouraging for obtaining the [amâ+âÎą-Al] mixture over a wide range of high temperature effective for the formation of Al-based high-strength nanostructured bulk alloys by warm working
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Novel deformation-induced polymorphic crystallization and softening of Al-based amorphous alloys
Š 2018 Acta Materialia Inc. Melt-spun amorphous ribbons of Al 90 Y 10 (at.%) (90Al) and Al 84 Y 8.5 Ni 4 Co 2 Pd 1 Fe 0.5 (84Al) are cold-rolled at near to liquid-nitrogen temperature or at room temperature, inducing partial crystallization to nanoscale fcc-Al (ι-Al). The crystallization is characterized and contrasted with the distinct sequences of reactions on annealing 90Al and 84Al amorphous alloys. Rolling-induced crystallization leads to softening, opposite to the effect of nanocrystallization induced by annealing. The origins of the hardness changes are analyzed. The rolling induces novel polymorphic crystallization to ι-Al with extended solid solubility. This transformation, which occurs equally in 84Al and 90Al, despite the much greater thermal stability of the former, allows the ribbons to retain good bending ductility, and delays the onset of embrittlement on subsequent annealing. Partial crystallization induced by cold-rolling is useful in avoiding the formation of compound phases associated with brittleness, and is a promising process for high-solute Al-based amorphous alloys to be further developed as structural materials
Generation of tooth profile for roots rotor based on virtual linkage associated with Assur group
This article, for the first time, presents the generation of Roots rotor tooth profiles based on an Assur-group-associated
virtual linkage method. Taking the original Roots rotor as an example, structure and geometry of the Roots rotor are
introduced, and based on the principle of inversion, an equivalent virtual linkage is identified for generating dedendum
tooth profile of the rotor. Using linkage decomposition associated with elemental Assur groups, algorithm for computing
the tooth curve is constructed leading to the explicit expression of rotor profile and the corresponding numerical simulation,
verifying the validity of the proposed approach. For demonstration purpose, the virtual linkage method is then
extended to the generation of tooth profiles for the variants of Roots rotors with arc-cycloidal curves and arc-involute
curves. Integrated with computer-aided design, computer-aided engineering and computer-aided manufacturing software
platforms, as well as the three-dimensional printing technology, this article provides an efficient and intuitive approach
for Roots rotor system design, analysis and development
Hypoxia and hypoxia inducible factor-1Îą are required for normal endometrial repair during menstruation
About a quarter of pre-menopausal women will suffer from heavy menstrual bleeding in their lives. Here, Maybin and colleagues show hypoxia and subsequent activation of HIF-1ι during menses are required for normal endometrial repair, and identify pharmacological stabilisation of HIF-1ι as a potential therapeutic strategy for this debilitating condition
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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