3,657 research outputs found
Anelastic spectroscopy study of the spin-glass and cluster spin-glass phases of LaSrCuO
The anelastic spectra of LaSrCuO have been measured at
liquid He temperatures slightly below and above the concentration which is considered to separate the spin-glass phase from the
cluster spin-glass (CSG) phase. For all the elastic energy loss
functions show a step below the temperature of freezing into
the CSG state, similarly to what found in samples well within the CSG phase,
but with a smaller amplitude. The excess dissipation in the CSG state is
attributed to the motion of the domain walls between the clusters of
antiferromagnetically correlated spin. These results are in agreement with the
recent proposal, based on inelastic neutron scattering, of an electronic phase
separation between regions with and , at least for
Comment: 5 pages, 3 figures, submitted to Phys. Rev.
One Size Does Not Fit All: Meeting the Health Care Needs of Diverse Populations
Proposes a framework for meeting patients' cultural and linguistic needs: policies and procedures that support cultural competence, data collection, population-tailored services, and internal and external collaborations. Includes a self-assessment tool
Homogeneous geodesics of non-unimodular Lorentzian Lie groups and naturally reductive Lorentzian spaces in dimension three
We determine, for all three-dimensional non-unimodular Lie groups equipped
with a Lorentzian metric, the set of homogeneous geodesics through a point.
Together with the results of [C] and [CM2], this leads to the full
classification of three-dimensional Lorentzian g.o. spaces and naturally
reductive spaces
Octahedral tilting, monoclinic phase and the phase diagram of PZT
Anelastic and dielectric spectroscopy measurements on PZT close to the
morphotropic (MPB) and antiferroelectric boundaries provide new insight in some
controversial aspects of its phase diagram. No evidence is found of a border
separating monoclinic (M) from rhombohedral (R) phases, in agreement with
recent structural studies supporting a coexistence of the two phases over a
broad composition range x < 0.5, with the fraction of M increasing toward the
MPB. It is also discussed why the observed maximum of elastic compliance
appears to be due to a rotational instability of the polarisation and therefore
cannot be explained by extrinsic softening from finely twinned R phase alone,
but indicates the presence also of M phase, not necessarily homogeneous.
A new diffuse transition is found within the ferroelectric phase near x ~
0.1, at a temperature T_IT higher than the well established boundary T_T to the
phase with tilted octahedra. It is proposed that around T_IT the octahedra
start rotating in a disordered manner and finally become ordered below T_T. In
this interpretation, the onset temperature for octahedral tilting monotonically
increases up to the antiferroelectric transition of PbZrO3, and the depression
of T_T(x) below x = 0.18 would be a consequence of the partial relieve of the
mismatch between the cation radii with the initial stage of tilting below T_IT.Comment: submitted to J. Phys.: Condens. Matte
The Degenerate Parametric Oscillator and Ince's Equation
We construct Green's function for the quantum degenerate parametric
oscillator in terms of standard solutions of Ince's equation in a framework of
a general approach to harmonic oscillators. Exact time-dependent wave functions
and their connections with dynamical invariants and SU(1,1) group are also
discussed.Comment: 10 pages, no figure
A Guide to Localized Frames and Applications to Galerkin-like Representations of Operators
This chapter offers a detailed survey on intrinsically localized frames and
the corresponding matrix representation of operators. We re-investigate the
properties of localized frames and the associated Banach spaces in full detail.
We investigate the representation of operators using localized frames in a
Galerkin-type scheme. We show how the boundedness and the invertibility of
matrices and operators are linked and give some sufficient and necessary
conditions for the boundedness of operators between the associated Banach
spaces.Comment: 32 page
Approximation of Fourier Integral Operators by Gabor multipliers
A general principle says that the matrix of a Fourier integral operator with
respect to wave packets is concentrated near the curve of propagation. We prove
a precise version of this principle for Fourier integral operators with a
smooth phase and a symbol in the Sjoestrand class and use Gabor frames as wave
packets. The almost diagonalization of such Fourier integral operators suggests
a specific approximation by (a sum of) elementary operators, namely modified
Gabor multipliers. We derive error estimates for such approximations. The
methods are taken from time-frequency analysis.Comment: 22. page
Associated Production of a W Boson and One b Jet
We calculate the production of a W boson and a single b jet to
next-to-leading order in QCD at the Fermilab Tevatron and the CERN Large Hadron
Collider. Both exclusive and inclusive cross sections are presented. We
separately consider the cross section for jets containing a single b quark and
jets containing a b-anti b pair. There are a wide variety of processes that
contribute, and it is necessary to include them all in order to have a complete
description at both colliders.Comment: LaTeX, 16 pages, 22 postscript figures; version published in Phys.
Rev.
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Enhanced near infrared optical access to the brain with a transparent cranial implant and scalp optical clearing.
We report on the enhanced optical transmittance in the NIR wavelength range (900 to 2400 nm) offered by a transparent Yttria-stabilized zirconia (YSZ) implant coupled with optical clearing agents (OCAs). The enhancement in optical access to the brain is evaluated upon comparing ex-vivo transmittance measurements of mice native skull and the YSZ cranial implant with scalp and OCAs. An increase in transmittance of up to 50% and attenuation lengths of up to 2.4 mm (i.e., a five-fold increase in light penetration) are obtained with the YSZ implant and the OCAs. The use of this ceramic implant and the biocompatible optical clearing agents offer attractive features for NIR optical techniques for brain theranostics
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