61,431 research outputs found
Nonlinear-optical frequency-doubling meta-reflector: pulsed regime
The properties of backward-wave second harmonic meta-reflector operating in
pulse regime are investigated. We show that ratio of the income pulse length to
the thickness of the metaslab determines its important operational properties
which are in contrast with those manifested at common second harmonic
generation settings.Comment: 6 pages, 3 figure
Second harmonic generation and pulse shaping in positively and negatively spatially dispersive nanowaveguides: comparative analysis
Comparative analysis of second harmonic generation in ordinary and
backward-wave settings is presented. Extraordinary properties of frequency
doubling nonlinear optical reflectivity and pulse shaping through phase
matching of ordinary and backward electromagnetic waves in the nanowaveguides
with mixed negative/positive spatial dispersion is demonstrated with numerical
simulations.Comment: 10 pages, 5 figure
Perturbation of spectra and spectral subspaces
We consider the problem of variation of spectral subspaces for linear
self-adjoint operators under off-diagonal perturbations. We prove a number of
new optimal results on the shift of the spectrum and obtain (sharp) estimates
on the norm of the difference of two spectral projections
Critical behavior of the Random-Field Ising model at and beyond the Upper Critical Dimension
The disorder-driven phase transition of the RFIM is observed using exact
ground-state computer simulations for hyper cubic lattices in d=5,6,7
dimensions. Finite-size scaling analyses are used to calculate the critical
point and the critical exponents of the specific heat, magnetization,
susceptibility and of the correlation length. For dimensions d=6,7 which are
larger or equal to the assumed upper critical dimension, d_u=6, mean-field
behaviour is found, i.e. alpha=0, beta=1/2, gamma=1, nu=1/2. For the analysis
of the numerical data, it appears to be necessary to include recently proposed
corrections to scaling at and beyond the upper critical dimension.Comment: 8 pages and 13 figures; A consise summary of this work can be found
in the papercore database at http://www.papercore.org/Ahrens201
Simulation study of gust alleviation in a tilt rotor aircraft, volume 1
The response to vertical turbulence in cruise of the HTR XV-15 design is studied using simulation techniques. This design is a modified version of the XV-15 with a hingeless fiberglass soft-in-plane rotor system. The parameters of a gust alleviation system are determined and the performance of the system is evaluated over a range of cruise velocities and altitudes
Generalized synchronization: a modified system approach
The universal mechanism resulting in the generalized synchronization regime
arising in the chaotic oscillators with the dissipative coupling has been
described. The reasons of the generalized synchronization occurrence may be
clarified by means of a modified system approach. The main results are
illustrated by unidirectionally coupled Rossler systems, Rossler and Lorenz
systems and logistic maps.Comment: 4 pages, 2 figure
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