Magnetic resonance elastography (MRE) is a promising modality for in vivo quantification and visualization of soft tissue elasticity. It involves three stages of processes for (1) external excitation, (2) wave imaging and (3) elasticity reconstruction. One of the important issues to be addressed in MRE is wave image processing and enhancement. In this study we approach it from three different w...

We use picosecond x-ray diffuse scattering to image the nonequilibrium vibrations in the lattice following ultrafast laser excitation. We present images of nonequilibrium phonons in InP and InSb throughout the Brillouin zone which remain out of equilibrium up to nanoseconds. The results are analyzed using a Born model that helps identify the phonon branches contributing to the observed features...

The paper presents preliminary numerical and experimental studies of active textile-reinforced thermoplastic composites with embedded sensor-actuator arrays. The goal of the investigations was the assessment of directional sound wave generation capability using embedded sensor-actuator arrays and developed a wave excitation procedure for ultrasound measurement tasks. The feasibility of the prop...

Using the differential theory of light diffraction by finite cylindrical objects, we study light transmission through a small circular aperture in a metallic screen with concentric corrugation around the nanohole. Poynting vector maps in the region below the screen show that the field enhancement compared with an unstructured aperture is obtained with corrugation lying on the entrance face of t...

It has been experimentally demonstrated only recently that a simultaneous excitation of interfering electric and magnetic resonances can lead to unidirectional scattering of visible light in zero-dimensional dielectric nanoparticles. We show both theoretically and experimentally, that strongly anisotropic scattering also occurs in individual dielectric nanowires. The effect occurs even under ei...

Differential pulse-width-pair BOTDA technique is combined with bi-directional Raman amplification and Simplex coding to achieve sub-meter spatial resolution over very long sensing distances. Numerical simulations are used to optimize the power levels of the Raman pumps, avoiding nonlinear effects and pump depletion. Distortions in the Brillouin gain spectrum due to acoustic-wave pre-excitation ...

In the theory of electrocardiography the direction of myocardial fibers has been almost ignored. In order to evaluate whether this is proper or not, directional difference of conduction velocity in the ventricular syncytium was examined by capillary microelectrodes. Conduction velocity in the direction of myocardial fibers was found to be usually several times larger than that vertical to them....

For the real-time identification of the time-variant, directional structure of the mobile radio channel impulse response, a broadband vector channel sounder is described. The measurement procedure relies on periodic multi-frequency excitation signals, correlation processing and joint delay-azimuth superresolution based on the ESPRIT algorithm. The underlying signal model is developed and the di...

It has been demonstrated that, in a one-dimensional wave system, monochromatic waves may be generated which are completely localized to the region of excitation or which propagate in only one direction. We further the discussion of such nonpropagating and directional excitations and demonstrate that they can be extended to excitations of an arbitrary finite number of frequencies. Two techniques...

Absfrucf-A comprehensive analysis of the symmetric nonlinear directional coupler as a function of the excitation conditions is reported. The analysis is based on a coupled-mode technique in normalized (dimensionless) parameters, using the linear supermodes of the guiding structure, most of the results being derived from the Hamiltonian of the resulting nonlinear equations. The exchange of power...