Parallel excitation [1,2] with a multi-element Radio Frequency (RF) transceiver array [3-9] as a contemporary methodology has been advocated for human MR imaging at ultrahigh magnetic fields (7 Tesla and above). In ultrahigh field MRI, the required high operating frequency and thus shortened wavelength of radio frequency waves creates a complex wave behavior and increased phase variation of RF ...

BACKGROUND AND OBJECTIVE The diagnostic contribution of cervical tissue fluorescence spectra acquired in vivo at 380 and 460 nm excitation were analyzed using a general multivariate statistical algorithm. MATERIALS AND METHODS The primary steps of the algorithm are to: (1) preprocess data to reduce interpatient and intrapatient variation of tissue spectra from the same diagnostic category, wi...

Strong localization effect in self-assembled InGaN quantum dots (QDs) grown by metalorganic chemical vapor deposition has been evidenced by temperature-dependent photoluminescence (PL) at different excitation power. The integrated emission intensity increases gradually in the range from 30 to 160 K and then decreases with a further increase in temperature at high excitation intensity, while thi...

Blueshifts of luminescence observed in type-II heterostructures are quantitatively examined in terms of a self-consistent approach including excitonic effects. This analysis shows that the main contribution to the blueshift originates from the well region rather than the variation of triangular potentials formed in the barrier region. The power law for the blueshift, ΔEPL ∝ Plaserm, from m = 1/...

A model of nonequilibrium charge recombination from an excited adiabatic state of a donor-acceptor complex induced by the nonadiabatic interaction operator is considered. The decay of the excited state population prepared by a short laser pulse is shown to be highly nonexponential. The influence of the excitation pulse carrier frequency on the ultrafast charge recombination dynamics of excited ...

The incremental stiffness characterizes the variation of a material's force response to a small deformation change. In lattices with noninteracting vibrational modes, the excitation of localized states does not have any effect on material properties, such as the incremental stiffness. We report that, in nonlinear lattices, driving a defect mode introduces changes in the static force-displacemen...

Standing-wave excitation of fluorescence is highly desirable in optical microscopy because it improves the axial resolution. We demonstrate here that multiplanar excitation of fluorescence by a standing wave can be produced in a single-spot laser scanning microscope by placing a plane reflector close to the specimen. We report here a variation in the intensity of fluorescence of successive plan...

Abstract: Wind turbine blades have to withstand the rigorous test of 20–25 years of service. Fatigue testing is an accurate method used to verify blade reliability. Multi-point excitation could better fit the fatigue damage distribution, which reduces the power output of a single exciter and saves testing energy consumption. The amplitude, phase, and frequency characteristics of the fatigue tes...

Nonlinear parametric excitation refers to the nonlinear analysis of a system of ordinary differential equations with periodic coefficients. In contrast to linear parametric excitation, which offers determinations of the stability of equilibria, nonlinear parametric excitation has as its goal the structure of the phase space, as given by a portrait of the Poincare map. In this article, perturbat...

The paper presents the speaker normalization technique we implemented in a teaching and training system for hearing handicapped children with the goal to reduce inter-speaker variability in time-frequency speech representation. In an effort to reduce variance caused by variation in vocal tract shape among speakers, a formant based nonlinear frequency warping approach to vocal tract normalizatio...