49,847 research outputs found
Analysis of delamination in fiber composite laminates out-of-plane under bending
Delamination in the form of cracking or separation between plies in an advanced fiber composite laminate is a problem of major concern. Both advanced analytical methods and advanced computational analyses are conducted to: (1) develop an asymptotic solution for a composite laminate subject to out-of-plane bending; (2) construct advanced singular finite elements in conjunction with the development of nonsingular elements for this bending problem; and (3) evaluate the delamination failure mechanics parameters and the subsequent modes of fracture. A parametric study was also conducted to evaluate the influences of various lamination parameters on the delaminated composites
Horizon Mass Theorem
A new theorem for black holes is found. It is called the horizon mass
theorem. The horizon mass is the mass which cannot escape from the horizon of a
black hole. For all black holes: neutral, charged or rotating, the horizon mass
is always twice the irreducible mass observed at infinity. Previous theorems on
black holes are: 1. the singularity theorem, 2. the area theorem, 3. the
uniqueness theorem, 4. the positive energy theorem. The horizon mass theorem is
possibly the last general theorem for classical black holes. It is crucial for
understanding Hawking radiation and for investigating processes occurring near
the horizon.Comment: A new theorem for black holes is establishe
Spectrum of low-lying configurations with negative parity
Spectrum of low-lying five-quark configurations with strangeness quantum
number and negative parity is studied in three kinds of constituent
quark models, namely the one gluon exchange, Goldstone Boson exchange, and
instanton-induced hyperfine interaction models, respectively. Our numerical
results show that the lowest energy states in all the three employed models are
lying at 1800 MeV, about 200 MeV lower than predictions of various
quenched three-quark models. In addition, it is very interesting that the state
with the lowest energy in one gluon exchange model is with spin 3/2, but 1/2 in
the other two models.Comment: Version published in Phys. Rev.
meson effects on neutron stars in the modified quark-meson coupling model
The properties of neutron stars are investigated by including meson
field in the Lagrangian density of modified quark-meson coupling model. The
population with meson is larger than that without
meson at the beginning, but it becomes smaller than that without meson
as the appearance of . The meson has opposite effects on
hadronic matter with or without hyperons: it softens the EOSes of hadronic
matter with hyperons, while it stiffens the EOSes of pure nucleonic matter.
Furthermore, the leptons and the hyperons have the similar influence on
meson effects. The meson increases the maximum masses of
neutron stars. The influence of on the meson effects
are also investigated.Comment: 10 pages, 6 figures, 4 table
From Jeff=1/2 insulator to p-wave superconductor in single-crystal Sr2Ir1-xRuxO4 (0 < x< 1)
Sr2IrO4 is a magnetic insulator assisted by strong spin-orbit coupling (SOC)
whereas the Sr2RuO4 is a p-wave superconductor. The contrasting ground states
have been shown to result from the critical role of the strong SOC in the
iridate. Our investigation of structural, transport, and magnetic properties
reveals that substituting 4d Ru4+ (4d4) ions for 5d Ir4+(5d5) ions in Sr2IrO4
directly adds holes to the t2g bands, reduces the SOC and thus rebalances the
competing energies in single-crystal Sr2Ir1-xRuxO4. A profound effect of Ru
doping driving a rich phase diagram is a structural phase transition from a
distorted I41/acd to a more ideal I4/mmm tetragonal structure near x=0.50 that
accompanies a phase transition from an antiferromagnetic-insulating state to a
paramagnetic-metal state. We also make a comparison drawn with Rh doped
Sr2IrO4, highlighting important similarities and differences.Comment: 18 pages,7 figure
Origin of the X-ray Emission in the Nuclei of FR Is
We investigate the X-ray origin in FRIs using the multi-waveband high
resolution data of eight FR I sources, which have very low Eddington ratios. We
fit their multi-waveband spectrum using a coupled accretion-jet model. We find
that X-ray emission in the source with the highest L_X (~1.8*10^-4 L_Edd) is
from the advection-dominated accretion flow (ADAF). Four sources with moderate
L_X(~several*10^-6 L_Edd) are complicated. The X-ray emission of one FR I is
from the jet, and the other three is from the sum of the jet and ADAF. The
X-ray emission in the three least luminous sources (L_X<1.0*10^-6L_Edd) is
dominated by the jet. These results roughly support the predictions of Yuan and
Cui(2005) where they predict that when the X-ray luminosity of the system is
below a critical value, the X-radiation will not be dominated by the emission
from the ADAF any longer, but by the jet. We also find that the accretion rates
in four sources must be higher than the Bondi rates, which implies that other
fuel supply (e.g., stellar winds) inside the Bondi radius should be important.Comment: 6 pages. To published in Journal of Physics, in proceedings of "The
Universe under the Microscope - Astrophysics at High Angular Resolution" (Bad
Honnef, Germany, April 2008), eds. R. Schoedel, A. Eckart, S. Pfalzner, and
E. Ro
Single top production in the -channel at LHC: a realistic test of electroweak models
We compute the complete electroweak one-loop effect on the process of
-channel single top production at LHC in the Standard Model and in the MSSM
within the mSUGRA symmetry breaking scheme. We find that the one-loop
electroweak SM effect is large, and decreases the cross section of an amount
that is of the same size as that of the NLO QCD one. The genuine SUSY effect in
the mSUGRA scheme, for a general choice of benchmark points, is rather small.
It might become large and visible in more general scenarios around thresholds
involving light stop and neutralino mass values.Comment: 28 pages, 10 eps figure
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