25,835 research outputs found
Transition from a mixed to a pure d-wave symmetry in superconducting optimally doped YBaCuO thin films under applied fields
We have probed the Landau levels of nodal quasi-particles by tunneling along
a nodal direction of (110) oriented YBaCuO thin films with a
magnetic field applied perpendicular to the planes, and parallel to the
film's surface. In optimally doped films and at low temperature, finite energy
nodal states are clearly observed in films thinner than the London penetration
depth. Above a well defined temperature the order parameter reverts to a pure
\emph{d}-wave symmetry.Comment: 4 pages, 4 figure
Polarwissenschaften in der Schule – IV. Internationaler Workshop für Lehrer und Wissenschaftler in Hannover – 1. bis 4. April 2015
The New Zealand Strong Motion Earthquake Recorder Network
The network of strong-motion earthquake recorders, maintained throughout
New Zealand by the Engineering Seismology Section of the Department of
Scientific and Industrial Research, is described. The instruments are either
deployed as ground instruments to measure potential earthquake attack on
structures, or in structures, e.g. buildings, dams and industrial installations,
to record structural response. Details are given of installation of instruments , maintenance, laboratory work, record retrieval and digitisation,
costs and staffing for the network. Future developments mooted include an
improved digitising system, the introduction of an improved version of the
existing mechanical-optical instrument in 1979, and, in the long term, the
introduction of an entirely new digital recorder, having an electrical
output from its accelerometers, which will make possible the transmission
of data by telephone or radio link
Temporal extensivity of Tsallis' entropy and the bound on entropy production rate
The Tsallis entropy, which is a generalization of the Boltzmann-Gibbs
entropy, plays a central role in nonextensive statistical mechanics of complex
systems. A lot of efforts have recently been made on establishing a dynamical
foundation for the Tsallis entropy. They are primarily concerned with nonlinear
dynamical systems at the edge of chaos. Here, it is shown by generalizing a
formulation of thermostatistics based on time averages recently proposed by
Carati [A. Carati, Physica A 348, 110 (2005)] that, whenever relevant, the
Tsallis entropy indexed by is temporally extensive: linear growth in time,
i.e., finite entropy production rate. Then, the universal bound on the entropy
production rate is shown to be . The property of the associated
probabilistic process, i.e., the sojourn time distribution, determining
randomness of motion in phase space is also analyzed.Comment: 25 pages, no figure
Parity-Violating Electron Scattering and Neucleon Structure
The measurement of parity violation in the helicity dependence of
electron-nucleon scattering provides unique information about the basic quark
structure of the nucleons. In this review, the general formalism of
parity-violating electron scattering is presented, with emphasis on elastic
electron-nucleon scattering. The physics issues addressed by such experiments
is discussed, and the major goals of the presently envisioned experimental
program are identified. %General aspects of the experimental technique are
reviewed and A summary of results from a recent series of experiments is
presented and the future prospects of this program are also discussed.Comment: 45 pages, 9 figure
Reconfigurable implementation of recursive DCT kernels for reduced quantization noise
Time multiplexed implementations of the recursive DCT
processors are widely used in many multimedia and compression applications. Recently proposed three Goertzel kernels offer significant improvement (up to 90 %) in the noise performance of the time-multiplexed architecture to allow word-length specifications get reduced. In this paper, a highly optimized reconfigurable DCT architecture is proposed that can perform the function of three different kemels (Type A, B and C) on Virtex FPG
Biases in the polarization position angles in the NVSS point source catalogue
We have examined the statistics of the polarization position angles
determined for point sources in the NRAO-VLA sky survey (NVSS) and find that
there is a statistically significant bias toward angles which are multiples of
45 degrees. The formal probability that the polarization angles are drawn from
a uniform distribution is exponentially small. When the sample of those NVSS
sources with polarizations detected with a signal to noise 3 is split
either around the median polarized flux density or the median fractional
polarization, the effect appears to be stronger for the more highly polarized
sources. Regions containing strong sources and regions at low galactic
latitudes are not responsible for the non-uniform distribution of position
angles. We identify CLEAN bias as the probable cause of the dominant effect,
coupled with small multiplicative and additive offsets on each of the Stokes
parameters. Our findings have implications for the extraction of science, such
as information concerning galactic magnetic fields, from large scale
polarization surveys
The neutron halo of He in a microscopic model
The two--neutron separation energy of He has been reproduced for the
first time in a realistic parameter--free microscopic multicluster model
comprising the and clusterizations, with cluster
breathing excitations included. The contribution of the channel is
substantial. A very thick (0.85 fm) neutron halo has been found in full
agreement with the results of the latest phenomenological analysis.Comment: Submitted to Phys. Rev. C, 8 pages, Latex with Revtex, 2 figures (not
included) available on request, 08-03-9
Light Baryon Resonances: Restrictions and Perspectives
The problem of nucleon resonances N' with masses below the Delta is
considered. We derive bounds for the properties of such states. Some of these
are new, while others improve upon existing limits. We discuss the nature of N'
states, and their unitary partners, assuming their existence can be verified.Comment: 11 pages, 11 figur
Synchrotron Radiation From Radiatively Inefficient Accretion Flow Simulations: Applications to Sgr A*
We calculate synchrotron radiation in three-dimensional pseudo-Newtonian
magnetohydrodynamic simulations of radiatively inefficient accretion flows. We
show that the emission is highly variable at optically thin frequencies, with
order of magnitude variability on time-scales as short as the orbital period
near the last stable orbit; this emission is linearly polarized at the 20-50 %
level due to the coherent toroidal magnetic field in the flow. At optically
thick frequencies, both the variability amplitude and polarization fraction
decrease significantly with decreasing photon frequency. We argue that these
results are broadly consistent with the observed properties of Sgr A* at the
Galactic Center, including the rapid infrared flaring.Comment: Accepted for publication in Ap
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