4,165 research outputs found
Existence of Multistring Solutions of the Self-Gravitating Massive Boson
We consider a semilinear elliptic system which include the model system of
the strings in the cosmology as a special case. We prove existence of
multi-string solutions and obtain precise asymptotic decay estimates near
infinity for the solutions.
As a special case of this result we solve an open problem posed in
\cite{yan}Comment: 12 page
Epitaxial growth and the magnetic properties of orthorhombic YTiO3 thin films
High-quality YTiO3 thin films were grown on LaAlO3 (110) substrates at low
oxygen pressures (<10-8 Torr) using pulsed laser deposition. The in-plane
asymmetric atomic arrangements at the substrate surface allowed us to grow
epitaxial YTiO3 thin films, which have an orthorhombic crystal structure with
quite different a- and b-axes lattice constants. The YTiO3 film exhibited a
clear ferromagnetic transition at 30 K with a saturation magnetization of about
0.7 uB/Ti. The magnetic easy axis was found to be along the [1-10] direction of
the substrate, which differs from the single crystal easy axis direction, i.e.,
[001].Comment: 14 pages, 4 figure
Determination of Dynamic Shear Modulus of Soils from Static Strength
A correlation study between the dynamic shear modulus obtained from the resonant column technique and the static strength obtained from the undrained triaxial compression test is described. The materials studied were a uniform sand, a non-active fine silty clay and a highly-active bentonite clay treated with additives to increase the range for static and dynamic shear strength of the soils. It is noted that a linear relationship exists between the dynamic shear modulus, except for those soil specimens having very low strength, independent of test parameters. Using linear regression analysis, empirical equations for predicting the maximum dynamic shear modulus from the static strength have been obtained for the three different soils
Direct observation of the proliferation of ferroelectric loop domains and vortex-antivortex pairs
We discovered "stripe" patterns of trimerization-ferroelectric domains in
hexagonal REMnO3 (RE=Ho, ---, Lu) crystals (grown below ferroelectric
transition temperatures (Tc), reaching up to 1435 oC), in contrast with the
vortex patterns in YMnO3. These stripe patterns roughen with the appearance of
numerous loop domains through thermal annealing just below Tc, but the stripe
domain patterns turn to vortex-antivortex domain patterns through a freezing
process when crystals cross Tc even though the phase transition appears not to
be Kosterlitz-Thouless-type. The experimental systematics are compared with the
results of our six-state clock model simulation and also the Kibble-Zurek
Mechanism for trapped topological defects
Global classical solutions for partially dissipative hyperbolic system of balance laws
This work is concerned with (-component) hyperbolic system of balance laws
in arbitrary space dimensions. Under entropy dissipative assumption and the
Shizuta-Kawashima algebraic condition, a general theory on the well-posedness
of classical solutions in the framework of Chemin-Lerner's spaces with critical
regularity is established. To do this, we first explore the functional space
theory and develop an elementary fact that indicates the relation between
homogeneous and inhomogeneous Chemin-Lerner's spaces. Then this fact allows to
prove the local well-posedness for general data and global well-posedness for
small data by using the Fourier frequency-localization argument. Finally, we
apply the new existence theory to a specific fluid model-the compressible Euler
equations with damping, and obtain the corresponding results in critical
spaces.Comment: 39 page
Asymmetry in fatigue and recovery in ferroelectric Pb(Zr,Ti)O3 thin-film capacitors
We investigate the fatigue and refreshment by dc-electrical field of the
electrical properties of Pt/Pb(Ti,Zr)O/Pt ferroelectric capacitors. We find
an asymmetry in the refreshment, that is, the fatigued state can be refreshed
by application of negative high dc-voltage to the top electrode, but no
refreshment is measured by positive dc-voltage application. We also find that
the fatigue can be prevented by driving the capacitor asymmetrically.Comment: 4 pages, 5 figure
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