3,131 research outputs found
Folding model study of the elastic scattering at low energies
The folding model analysis of the elastic scattering at the
incident energies below the reaction threshold of 34.7 MeV (in the lab system)
has been done using the well-tested density dependent versions of the M3Y
interaction and realistic choices for the He density. Because the
absorption is negligible at the energies below the reaction threshold, we were
able to probe the optical potential at low energies quite
unambiguously and found that the overlap density used to
construct the density dependence of the M3Y interaction is strongly distorted
by the Pauli blocking. This result gives possible explanation of a
long-standing inconsistency of the double-folding model in its study of the
elastic and -nucleus scattering at low energies using
the same realistic density dependent M3Y interaction
Topological Lifshitz phase transition in effective model of QCD with chiral symmetry non-restoration
The topological Lifshitz phase transition is studied systematically within an
effective model of QCD, in which the chiral symmetry, broken at zero
temperature, is not restored at high temperature and/or baryon chemical
potential. It is found that during phase transition the quark system undergoes
a first-order transition from low density fully-gapped state to high density
state with Fermi sphere which is protected by momentum-space topology. The
Lifshitz phase diagram in the plane of temperature and baryon chemical
potential is established. The critical behaviors of various equations of state
are determined.Comment: 8 pages, 10 figure
Was the Higgs boson discovered?
The standard model has postulated the existence of a scalar boson, named the
Higgs boson. This boson plays a central role in a symmetry breaking scheme
called the Brout-Englert-Higgs mechanism (or the
Brout-Englert-Higgs-Guralnik-Hagen-Kibble mechanism, for completeness) making
the standard model realistic. However, until recently at least, the
50-year-long-sought Higgs boson had remained the only particle in the standard
model not yet discovered experimentally. It is the last but very important
missing ingredient of the standard model. Therefore, searching for the Higgs
boson is a crucial task and an important mission of particle physics. For this
purpose, many theoretical works have been done and different experiments have
been organized. It may be said in particular that to search for the Higgs boson
has been one of the ultimate goals of building and running the LHC, the world's
largest and most powerful particle accelerator, at CERN, which is a great
combination of science and technology. Recently, in the summer of 2012, ATLAS
and CMS, the two biggest and general-purpose LHC collaborations, announced the
discovery of a new boson with a mass around 125 GeV. Since then, for over two
years, ATLAS, CMS and other collaborations have carried out intensive
investigations on the newly discovered boson to confirm that this new boson is
really the Higgs boson (of the standard model). It is a triumph of science and
technology and international cooperation. Here, we will review the main results
of these investigations following a brief introduction to the Higgs boson
within the theoretical framework of the standard model and Brout-Englert-Higgs
mechanism as well as a theoretical and experimental background of its search.
This paper may attract interest of not only particle physicists but also a
broader audience.Comment: LateX, 23 pages, 01 table, 9 figures. To appear in Commun. Phys.
Version 2: Minor changes, two references adde
Stabilization Control of the Differential Mobile Robot Using Lyapunov Function and Extended Kalman Filter
This paper presents the design of a control model to navigate the
differential mobile robot to reach the desired destination from an arbitrary
initial pose. The designed model is divided into two stages: the state
estimation and the stabilization control. In the state estimation, an extended
Kalman filter is employed to optimally combine the information from the system
dynamics and measurements. Two Lyapunov functions are constructed that allow a
hybrid feedback control law to execute the robot movements. The asymptotical
stability and robustness of the closed loop system are assured. Simulations and
experiments are carried out to validate the effectiveness and applicability of
the proposed approach.Comment: arXiv admin note: text overlap with arXiv:1611.07112,
arXiv:1611.0711
A new prismatic solid-shell element 'SHB6' : assumed-strain formulation and evaluation on benchmark problems
In this paper, the formulation of a new six-node solidâshell element denoted (SHB6) is proposed. This prismatic element is based on a purely three-dimensional approach, and hence has displacements as the only degrees of freedom. A reduced integration scheme is adopted consisting of one-point in-plane quadrature and an arbitrary number of integration points, with a minimum number of two, distributed along the âthicknessâ direction. Moreover, in order to enhance its performance and to greatly reduce most locking effects, specific projections are introduced based on the assumed-strain method. The resulting derivation can then be used to model thin structural problems, while taking into account the various through-thickness phenomena. A careful analysis of potential stiffness matrix rank deficiencies reveals that no hourglass modes need to be controlled. However, without assumed-strain method, the element exhibits some shear and thickness-type locking, which is common in linear triangular elements associated with constant strain states. After the formulation of the element is detailed, its performance is assessed through a set of representative benchmark problems illustrating its capabilities in various situations. More specifically, this prismatic solidâshell element proves to be an essential complement to the SHB8PS hexahedral element in meshing arbitrarily complex geometries.Cifre EDF R&
Construction and analysis of localized responses for gradient damage models in a 1D setting
International audienceWe propose a method of construction of non homogeneous solutions to the problem of traction of a bar made of an elastic-damaging material whose softening behavior is regularized by a gradient damage model. We show that, for sufficiently long bars, localization arises on sets whose length is proportional to the material internal length and with a profile which is also characteristic of the material. We point out the very sensitivity of the responses to the parameters of the damage law. All these theoretical considerations are illustrated by numerical examples
2D-model of contaminant water transmission processes and numerical simulation on a natural lake
Nowadays, the water pollution problems in the lakes are urgent matters. The simulation of contaminant water transmission process plays important role in reality to improve people's life qualities. In this paper the 2D-mathematical model simulating transmission processes of some contaminant substances in one lake of Hanoi is studied. The finite volume method is used in model. The actions between substances are considered and the simulation results are compared with the measurements
Crack identification in multiple cracked beams made of functionally graded material by using stationary wavelet transform of mode shapes
This paper presents crack identification in multiple cracked beams made of functionally graded material (FGM) by using stationary wavelet transform (SWT) of mode shapes and taking into account influence of Gaussian noise. Mode shapes are obtained from multiple cracked FGM beam element and spring model of cracks. The theoretical development was illustrated and validated by numerical examples. The investigated results show that crack identification method by using SWT of mode shapes is efficient and realizable
Performance analysis of global local mean square error criterion of stochastic linearization for nonlinear oscillator
The paper presents a performance analysis of global-local mean square error criterion of stochastic linearization for some nonlinear oscillators. This criterion of stochastic linearization for nonlinear oscillators bases on dual conception to the local mean square error criterion (LOMSEC). The algorithm is generally built to multi-degree of freedom (MDOF) nonlinear oscillators. Then, the performance analysis is carried out for two applications which comprise a rolling ship oscillation and two-degree of freedom one. The improvement on accuracy of the proposed criterion has been shown in comparison with the conventional Gaussian equivalent linearization (GEL)
PARTITION OF POLYCYCLIC AROMATIC HYDROCARBONS IN WATER-SEDIMENT SYSTEM CONTAINING HUMIC ACID
Natural dissolved organic matter (DOM) in the water environment has the potential to enhance the solubility of PAHs into the water phase, resulting in strong influence on their environmental fate. In this study, Nordic aquatic humic acid (HA) was used as a DOM. The effect of HA on the partition behaviour of PAHs in the sediment water system was examined by comparing the partition of three PAHs: Phenanthrene (Phe), Pyrene (Pyr), and Benzo[a]pyrene (BaP) in the water sediment system. An isotherm partition of PAHs between water and sediment was studied. The presence of HA in the sediment water system shifted the sediment water  partition of PAHs to the water phase. The more hydrophobic the PAH was, the stronger the effect of HA on Kd was. Observed KDOM fitted well the linear free energy relationship. A three-phase partitioning model was established and successfully described the partition behavior of PAHs in water-sediment system
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