49,384 research outputs found
Common drive unit
The Common Drive Unit (CDU) is a high reliability rotary actuator with many versatile applications in mechanism designs. The CDU incorporates a set of redundant motor-brake assemblies driving a single output shaft through differential. Tachometers provide speed information in the AC version. Operation of both motors, as compared to the operation of one motor, will yield the same output torque with twice the output speed
Eddy current damper
A high torque capacity eddy current damper used as a rate limiting device for a large solar array deployment mechanism is discussed. The eddy current damper eliminates the problems associated with the outgassing or leaking of damping fluids. It also provides performance advantages such as damping torque rates, which are truly linear with respect to input speed, continuous 360 degree operation in both directions of rotation, wide operating temperature range, and the capability of convenient adjustment of damping rates by the user without disassembly or special tools
Electroweak supersymmetric effects on high energy unpolarized and polarized single top production at LHC
We consider various processes of single top production at LHC in the
theoretical framework of the MSSM and examine the role of the supersymmetric
electroweak one-loop corrections in a special moderately light SUSY scenario,
in an initial parton-pair c.m. high energy range where a logarithmic asymptotic
expansion of Sudakov type can be used. We show that the electroweak virtual
effects are systematically large, definitely beyond the relative ten percent
size, particularly for a final pair where a special enhancement is
present. We show then in a qualitative way the kind of precision tests of the
model that would be obtainable from accurate measurements of the energy
distributions of the various cross sections and of the top polarization
asymmetries.Comment: 30 pages, 9 figure
Oxide-apertured microcavity single-photon emitting diode
We have developed a microcavity single-photon source based on a single
quantum dot within a planar cavity in which wet-oxidation of a high-aluminium
content layer provides lateral confinement of both the photonic mode and the
injection current. Lateral confinement of the optical mode in optically pumped
structures produces a strong enhancement of the radiative decay rate. Using
microcavity structures with doped contact layers, we demonstrate a
single-photon emitting diode where current may be injected into a single dot
CP Violation in Heavy MSSM Higgs Scenarios
We introduce and explore new heavy Higgs scenarios in the Minimal
Supersymmetric Standard Model (MSSM) with explicit CP violation, which have
important phenomenological implications that may be testable at the LHC. For
soft supersymmetry-breaking scales M_S above a few TeV and a charged Higgs
boson mass M_H+ above a few hundred GeV, new physics effects including those
from explicit CP violation decouple from the light Higgs boson sector. However,
such effects can significantly alter the phenomenology of the heavy Higgs
bosons while still being consistent with constraints from low-energy
observables, for instance electric dipole moments. To consider scenarios with a
charged Higgs boson much heavier than the Standard Model (SM) particles but
much lighter than the supersymmetric particles, we revisit previous
calculations of the MSSM Higgs sector. We compute the Higgs boson masses in the
presence of CP violating phases, implementing improved matching and
renormalization group (RG) effects, as well as two-loop RG effects from the
effective two-Higgs Doublet Model (2HDM) scale M_H+ to the scale M_S. We
illustrate the possibility of non-decoupling CP-violating effects in the heavy
Higgs sector using new benchmark scenarios named CPX4LHC.Comment: 39 pages, 17 figures, LaTeX, typos correcte
Virtual RTCP: A Case Study of Monitoring and Repair for UDP-based IPTV Systems
IPTV systems have seen widespread deployment, but often lack robust mechanisms for monitoring the quality of experience. This makes it difficult for network operators to ensure that their services match the quality of traditional broadcast TV systems, leading to consumer dissatisfaction. We present a case study of virtual RTCP, a new framework for reception quality monitoring and reporting for UDP-encapsulated MPEG video delivered over IP multicast. We show that this allows incremental deployment of reporting infrastructure, coupled with effective retransmission-based packet loss repair
Low-Energy Theorems for QCD at Finite Temperature and Chemical Potential
The low-energy theorems for QCD are generalized to finite temperature. and
chemical potential, including non-zero quark masses.Comment: 6 pages late
Moderate deviations for random field Curie-Weiss models
The random field Curie-Weiss model is derived from the classical Curie-Weiss
model by replacing the deterministic global magnetic field by random local
magnetic fields. This opens up a new and interestingly rich phase structure. In
this setting, we derive moderate deviations principles for the random total
magnetization , which is the partial sum of (dependent) spins. A typical
result is that under appropriate assumptions on the distribution of the local
external fields there exist a real number , a positive real number
, and a positive integer such that satisfies
a moderate deviations principle with speed and rate
function , where .Comment: 21 page
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