642 research outputs found
XFEM Simulation of Pore-Induced Fracture of a Heterogeneous Concrete Beam in Three-Point Bending
The extended finite element method with the linear softening law is employed to simulate poreinduced crack initiation and propagation in heterogeneous plain concrete beams in three-point bending. A series of numerical simulations was performed and experimentally validated. The crack was found to always initiate at the beam bottom in the point nearest to the pore, propagating through it. When the pore has a larger offset from the beam midspan, the beam displays higher fracture resistance and energy dissipation spent for fracture. With an increase in a distance from the beam bottom, the ultimate load also increases, but the energy dissipation slightly varies. The pore sizes have a little effect on the fracture resistance of the concrete beam.Моделирование вызванных пористостью зарождения и распространения трещины в бетонных балках неоднородной структуры при трехточечном изгибе выполнено с помощью расширенного метода конечных элементов и закона линейного разупрочнения. Проведен ряд операций численного моделирования, проверенных экспериментально. Установлено, что трещина всегда зарождается на нижней грани балки в точке, ближайшей к поре, прорастая сквозь нее. Если пора в большей степени смещена относительно среднего пролета балки, последняя проявляет более высокое сопротивление разрушению и диссипацию энергии, затрачиваемой на разрушение. По мере увеличения расстояния от поры до нижней грани балки допустимая нагрузка также возрастает, а диссипация энергии несколько изменяется. Показано, что размеры пор оказывают незначительное влияние на сопротивление бетонной балки разрушению
Baryon Antibaryon Nonets
The baryon-antibaryon SU(3) nonets are proposed as a scheme to classify the
increased number of experimentally observed enhancements near the baryon
antibaryon mass threshold. The scheme is similar to the Fermi-Yang-Sakata
model, which was put forth about fifty years ago in explaining the mesons
observed at that time. According to the present scheme, many new
baryon-antibaryon bound states are predicted, and their possible productions in
quarkonium decays and B decays are suggested for experimental search.Comment: 5 pages, 1 figur
Recognizing basal cell carcinoma on smartphone‐captured digital histopathology images with a deep neural network
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154530/1/bjd18026.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154530/2/bjd18026_am.pd
Long-distant contribution and radiative decays to light vector meson
The discrepancy between the PQCD calculation and the CLEO data for
() stimulates our interest in
exploring extra mechanism of decay. In this work, we apply an
important non-perturbative QCD effect, i.e., hadronic loop mechanism, to study
radiative decay. Our numerical result shows that the
theoretical results including the hadronic loop contribution and the PQCD
calculation of are consistent with the corresponding
CLEO data of . We expect further experimental
measurement of at BES-III, which will be helpful to
test the hadronic loop effect on decay.Comment: 7 pages, 2 figures. Accepted for publication in Eur. Phys. J.
Magnetic Fields in the Milky Way
This chapter presents a review of observational studies to determine the
magnetic field in the Milky Way, both in the disk and in the halo, focused on
recent developments and on magnetic fields in the diffuse interstellar medium.
I discuss some terminology which is confusingly or inconsistently used and try
to summarize current status of our knowledge on magnetic field configurations
and strengths in the Milky Way. Although many open questions still exist, more
and more conclusions can be drawn on the large-scale and small-scale components
of the Galactic magnetic field. The chapter is concluded with a brief outlook
to observational projects in the near future.Comment: 22 pages, 5 figures, to appear in "Magnetic Fields in Diffuse Media",
eds. E.M. de Gouveia Dal Pino and A. Lazaria
Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp nucleosynthesis processes
© 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∼10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous νp-process simulations.Peer reviewe
The Periodic Instability of Diameter of ZnO Nanowires via a Self-oscillatory Mechanism
ZnO nanowires with a periodic instability of diameter were successfully prepared by a thermal physical vapor deposition method. The morphology of ZnO nanowires was investigated by SEM. SEM shows ZnO possess periodic bead-like structure. The instability only appears when the diameter of ZnO nanowires is small. The kinetics and mechanism of Instability was discussed at length. The appearance of the instability is due to negative feed-back mechanism under certain experimental conditions (crystallization temperature, vapor supersaturation, etc)
Partial Wave Analysis of
BES data on are presented. The
contribution peaks strongly near threshold. It is fitted with a
broad resonance with mass MeV, width MeV. A broad resonance peaking at 2020 MeV is also required
with width MeV. There is further evidence for a component
peaking at 2.55 GeV. The non- contribution is close to phase
space; it peaks at 2.6 GeV and is very different from .Comment: 15 pages, 6 figures, 1 table, Submitted to PL
The energy spectrum of all-particle cosmic rays around the knee region observed with the Tibet-III air-shower array
We have already reported the first result on the all-particle spectrum around
the knee region based on data from 2000 November to 2001 October observed by
the Tibet-III air-shower array. In this paper, we present an updated result
using data set collected in the period from 2000 November through 2004 October
in a wide range over 3 decades between eV and eV, in which
the position of the knee is clearly seen at around 4 PeV. The spectral index is
-2.68 0.02(stat.) below 1PeV, while it is -3.12 0.01(stat.) above 4
PeV in the case of QGSJET+HD model, and various systematic errors are under
study now.Comment: 12 pages, 7 figures, accepted by Advances in space researc
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