15,247 research outputs found
Dyadic Sets, Maximal Functions and Applications on --Groups
Let be the Lie group endowed with the
left-invariant Riemannian symmetric space structure and the right Haar measure
, which is a Lie group of exponential growth. Hebisch and Steger in
[Math. Z. 245(2003), 37--61] proved that any integrable function on
admits a Calder\'on--Zygmund decomposition which involves a particular family
of sets, called Calder\'on--Zygmund sets. In this paper, we first show the
existence of a dyadic grid in the group , which has {nice} properties
similar to the classical Euclidean dyadic cubes. Using the properties of the
dyadic grid we shall prove a Fefferman--Stein type inequality, involving the
dyadic maximal Hardy--Littlewood function and the dyadic sharp dyadic function.
As a consequence, we obtain a complex interpolation theorem involving the Hardy
space and the space introduced in [Collect. Math. 60(2009),
277--295].Comment: Math. Z. (to appear
Frequency reconfigurable patch antenna for 4G LTE applications
A compact printed multi-band frequency reconfigurable patch antenna for 4G LTE applications is presented in this paper (50 x 60 x 1.6 mm3). The antenna consists of W-shaped and Inverted-U shaped patch lines connected in a Tree-shape on the front side of the antenna. The back-side of the antenna contains a 90°-tilted T-shaped strip connected with an Inverted-L shaped strip which is shorted with a patch on the front side for increasing the electrical length to cover lower frequency bands. Frequency reconfigurability is achieved by inserting three switches i.e., PIN diodes. The most critical part of this work is the designing of RLC-based DC line circuits for providing the DC biasing to the PIN diodes used as switches and inserting them at optimum locations. This antenna is reconfigurable among eight different 4G LTE frequency bands including 0.9 GHz, 1.4 GHz, 1.5 GHz, 1.6 GHz, 1.7 GHz, 1.8 GHz, 2.6 GHz, 3.5 GHz and WLAN band 2.5 GHz. The antenna exhibits different radiation patterns having a different direction of peak gain at different frequencies and for different switching combinations. The antenna is simulated with CST, and a prototype is fabricated to compare the measured and simulated results with good accuracy
Photospheric Electric Fields and Energy Fluxes in the Eruptive Active Region NOAA 11158
How much electromagnetic energy crosses the photosphere in evolving solar
active regions? With the advent of high-cadence vector magnetic field
observations, addressing this fundamental question has become tractable. In
this paper, we apply the "PTD-Doppler-FLCT-Ideal" (PDFI) electric field
inversion technique of Kazachenko et al. (2014) to a 6-day HMI/SDO vector
magnetogram and Doppler velocity sequence, to find the electric field and
Poynting flux evolution in active region NOAA 11158, which produced an X2.2
flare early on 2011 February 15. We find photospheric electric fields ranging
up to V/cm. The Poynting fluxes range from to
ergscms, mostly positive, with the largest contribution to
the energy budget in the range of -
ergscms. Integrating the instantaneous energy flux over
space and time, we find that the total magnetic energy accumulated above the
photosphere from the initial emergence to the moment before the X2.2 flare to
be ergs, which is partitioned as and
ergs, respectively, between free and potential energies.
Those estimates are consistent with estimates from preflare non-linear
force-free field (NLFFF) extrapolations and the Minimum Current Corona
estimates (MCC), in spite of our very different approach. This study of
photospheric electric fields demonstrates the potential of the PDFI approach
for estimating Poynting fluxes and opens the door to more quantitative studies
of the solar photosphere and more realistic data-driven simulations of coronal
magnetic field evolution.Comment: 51 pages, 10 figures, accepted by ApJ on August 11, 201
Interaction of the proteins which regulate MHC class II-mediated antigen presentation by antigen presenting cells
Equilibrium states for sectional-hyperbolic attractors
It has been conjectured that the original Lorenz attractor supports a unique
measure of maximal entropy. In this article, we give a partial answer to this
question (and its higher-dimensional counterpart) by considering the uniqueness
of equilibrium states for H\"older continuous functions on a
sectional-hyperbolic attractor . We prove that -open and densely,
if the point masses at singularities are not equilibrium states, then there
exists a unique equilibrium state supported on . In particular, there
exists a unique measure of maximal entropy for the flow
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