9,951 research outputs found
Phase control circuits using frequency multiplications for phased array antennas
A phase control coupling circuit for use with a phased array antenna is described. The coupling circuit includes a combining circuit which is coupled to a transmission line, a frequency multiplier circuit which is coupled to the combining circuit, and a recombining circuit which is coupled between the frequency multiplier circuit and phased array antenna elements. In a doubler embodiment, the frequency multiplier circuit comprises frequency doublers and the combining and recombining circuits comprise four-port hybrid power dividers. In a generalized embodiment, the multiplier circuit comprises frequency multiplier elements which multiply to the Nth power, the combining circuit comprises four-part hybrid power dividers, and the recombinding circuit comprises summing circuits
Phase interpolation circuits using frequency multiplication for phased arrays
Antenna phasing circuit is described with the following advantages - 1/ increased number of phased elements, 2/ current repetition for each array element, 3/ circuit simplicity, and 4/ accurate phase interpolation. This circuit functions with Huggins Scan or with nearly any other phasing system
The Relationship between Resilience and Body Image in College Women
Possessing a negative body image is associated with unhealthy eating habits and eating disorders in college women and has been linked to depression and negative feelings of self worth. Limited research exists on protective factors that have the potential to mitigate body image dissatisfaction. This paper examines the relationship of resilience to body image dissatisfaction in college women. Female, undergraduate college students were studied using previously validated measures. Results indicate that increased resilience is associated with improved body image
The Double Pentaladder Integral to All Orders
We compute dual-conformally invariant ladder integrals that are capped off by
pentagons at each end of the ladder. Such integrals appear in six-point
amplitudes in planar N=4 super-Yang-Mills theory. We provide exact,
finite-coupling formulas for the basic double pentaladder integrals as a single
Mellin integral over hypergeometric functions. For particular choices of the
dual conformal cross ratios, we can evaluate the integral at weak coupling to
high loop orders in terms of multiple polylogarithms. We argue that the
integrals are exponentially suppressed at strong coupling. We describe the
space of functions that contains all such double pentaladder integrals and
their derivatives, or coproducts. This space, a prototype for the space of
Steinmann hexagon functions, has a simple algebraic structure, which we
elucidate by considering a particular discontinuity of the functions that
localizes the Mellin integral and collapses the relevant symbol alphabet. This
function space is endowed with a coaction, both perturbatively and at finite
coupling, which mixes the independent solutions of the hypergeometric
differential equation and constructively realizes a coaction principle of the
type believed to hold in the full Steinmann hexagon function space.Comment: 70 pages, 3 figures, 4 tables; v2, minor typo corrections and
clarification
Bootstrapping a Five-Loop Amplitude Using Steinmann Relations
The analytic structure of scattering amplitudes is restricted by Steinmann
relations, which enforce the vanishing of certain discontinuities of
discontinuities. We show that these relations dramatically simplify the
function space for the hexagon function bootstrap in planar maximally
supersymmetric Yang-Mills theory. Armed with this simplification, along with
the constraints of dual conformal symmetry and Regge exponentiation, we obtain
the complete five-loop six-particle amplitude.Comment: 5 pages, 2 figures, 1 impressive table, and 2 ancillary files. v2: a
few clarifications and references added; version to appear in PR
Two-Sided Derivatives for Regular Expressions and for Hairpin Expressions
The aim of this paper is to design the polynomial construction of a finite
recognizer for hairpin completions of regular languages. This is achieved by
considering completions as new expression operators and by applying derivation
techniques to the associated extended expressions called hairpin expressions.
More precisely, we extend partial derivation of regular expressions to
two-sided partial derivation of hairpin expressions and we show how to deduce a
recognizer for a hairpin expression from its two-sided derived term automaton,
providing an alternative proof of the fact that hairpin completions of regular
languages are linear context-free.Comment: 28 page
Alien Registration- Caron, Marie J. (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29264/thumbnail.jp
Fluctuation, dissipation, and thermalization in non-equilibrium AdS_5 black hole geometries
We give a simple recipe for computing dissipation and fluctuations
(commutator and anti-commutator correlation functions) for non-equilibrium
black hole geometries. The recipe formulates Hawking radiation as an initial
value problem, and is suitable for numerical work. We show how to package the
fluctuation and dissipation near the event horizon into correlators on the
stretched horizon. These horizon correlators determine the bulk and boundary
field theory correlation functions. In addition, the horizon correlators are
the components of a horizon effective action which provides a quantum
generalization of the membrane paradigm. In equilibrium, the analysis
reproduces previous results on the Brownian motion of a heavy quark. Out of
equilibrium, Wigner transforms of commutator and anti-commutator correlation
functions obey a fluctuation-dissipation relation at high frequency.Comment: 28 pages, 6 figure
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