5,690 research outputs found
High efficiency multifrequency feed
Antenna systems and particularly compact and simple antenna feeds which can transmit and receive simultaneously in at least three frequency bands, each with high efficiency and polarization diversity are described. The feed system is applicable for frequency bands having nominal frequency bands with the ratio 1:4:6. By way of example, satellite communications telemetry bands operate in frequency bands 0.8 - 1.0 GHz, 3.7 - 4.2 GHz and 5.9 - 6.4 GHz. In addition, the antenna system of the invention has monopulse capability for reception with circular or diverse polarization at frequency band 1
On Einstein-Hilbert type action of superon-graviton model(SGM)
The fundamental action of superon-graviton model(SGM) of Einstein-Hilbert
type for space-time and matter is written down explicitly in terms of the
fields of the graviton and superons by using the affine connection formalism
and the spin connection formalism. Some characteristic structures including
some hidden symmetries of the gravitational coupling of superons are manifested
(in two dimensional space-time) with some details of the calculations. SGM
cosmology is discussed briefly.Comment: 20 pages, Latex, some more discussions and new references adde
Ambipolar transport in bulk crystals of a topological insulator by gating with ionic liquid
We report that the ionic-liquid gating of bulk single crystals of a
topological insulator can control the type of the surface carriers and even
results in ambipolar transport. This was made possible by the use of a highly
bulk-insulating BiSbTeSe2 system where the chemical potential is located close
to both the surface Dirac point and the middle of the bulk band gap. Thanks to
the use of ionic liquid, the control of the surface chemical potential by
gating was possible on the whole surface of a bulk three-dimensional sample,
opening new experimental opportunities for topological insulators. In addition,
our data suggest the existence of a nearly reversible electrochemical reaction
that causes bulk carrier doping into the crystal during the ionic-liquid gating
process.Comment: 7 pages, 6 figures, 2 tables; significantly expanded version to fully
discuss the gating process and its side effects; published in PR
On confined fractional charges: a simple model
We address the question whether features known from quantum chromodynamics
(QCD) can possibly also show up in solid-state physics. It is shown that
spinless fermions of charge on a checkerboard lattice with nearest-neighbor
repulsion provide for a simple model of confined fractional charges. After
defining a proper vacuum the system supports excitations with charges
attached to the ends of strings. There is a constant confining force acting
between the fractional charges. It results from a reduction of vacuum
fluctuations and a polarization of the vacuum in the vicinity of the connecting
strings.Comment: 5 pages, 3 figure
On N = 2 superfield for N = 2 vector supermultiplet in two dimensional spacetime
We focus on the superfield formulation for a N = 2 vector supermultiplet in
two dimensional spacetime and explicitly show that the Wess-Zumino gauge
condition for a N = 2 superfield is compatible with familiar SUSY (plus U(1)
gauge) transformations for the vector supermultiplet. N = 2 SUSY invariant mass
and Yukawa interaction terms for the vector supermultiplet are also constructed
from the superfield explicitly in addition to a free (kinetic) action.Comment: 8 pages, some discussions changed, references adde
Scaffolded Antigens in Yeast Cell Particle Vaccines Provide Protection against Systemic Polyoma Virus Infection
Background. U65, a self-aggregating peptide scaffold, traps fused protein antigens in yeast cells. Conversion to Yeast Cell Particle (YCP) vaccines by partial removal of surface mannoproteins exposes beta-glucan, mediating efficient uptake by antigen-presenting cells (APCs). YCP vaccines are inexpensive, capable of rapid large-scale production and have potential for both parenteral and oral use. Results. YCP processing by alkaline hydrolysis exposes up to 20% of the glucan but converts scaffolded antigen and internal yeast proteins into a common aggregate, preventing selective yeast protein removal. For U65-green fluorescent protein (GFP) or U65-Apolipoprotein A1 (ApoA1) subcutaneous vaccines, maximal IgG responses in mice required 10% glucan exposure. IgG responses to yeast proteins were 5-fold lower. Proteolytic mannoprotein removal produced YCPs with only 6% glucan exposure, insufficiently porous for selective removal of even native yeast proteins. Vaccine efficacy was reduced 10-fold. Current YCP formulations, therefore, are not suitable for human use but have considerable potential for use in feed animal vaccines. Significantly, a YCP vaccine expressing a GFP fusion to VP1, the murine polyoma virus major capsid protein, after either oral or subcutaneous administration, protected mice against an intraperitoneal polyoma virus challenge, reducing viral DNA levels in spleen and liver by \u3e 98%
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