We present exact, nonsingular solutions of the scalar-wave equation for beams that are nondiffracting. This means that the intensity pattern in a transverse plane is unaltered by propagating in free space. These beams can have extremely narrow intensity profiles with effective widths as small as several wavelengths and yet possess an infinite depth of field. We further show (by using numerical ...

Modern technology asks for thin films of sustainable piezoelectrics, whereas electro-mechanical properties such are poorly explored and controlled. Here, dynamic quasi-static polarization, dielectric, piezoelectric responses were experimentally studied in thin-film stacks barium titanate sandwiched between electrodes grown on top strontium substrate. Accurate characterization was secured by usi...

impact is one of the most important subjects which always have been considered in mechanical science. nature of impact is such that which makes its control a hard task. therefore it is required to adopt a safe and secure mechanism for transferring the impact to other vulnerable parts of a structure, when it is necessary. one of the best methods of absorbing impact energy is using thin-walled tu...

in this article, vehicle cornering stability and brake stabilization via bifurcation analysis has been investigated. in order to extract the governing equations of motion, a nonlinear four-wheeled vehicle model with two degrees of freedom has been developed. using the continuation software package matcont a stability analysis based on phase plane analysis and bifurcation of equilibrium is perfo...

free vibration of sandwich plates with temperature dependent functionally graded (fg) face sheets in various thermal environments is investigated. the material properties of fg face sheets are assumed to be temperature-dependent and vary continuously through the thickness according to a power-law distribution in terms of the volume fractions of the constituents. also, the material properties of...

a fundamental assumption in prosthetic dentistry is that the axis-orbital plane will usually be parallel to the horizontal reference plane. most articulator systems have incorporated this concept into their designs and use orbitale as the anterior reference point for transferring the vertical position of the maxilla to the articulator. clinical observations of cantonese patients suggest that in...

We present an analysis of the diffuse emission at 5 GHz in the first quadrant of the Galactic plane using two months of preliminary intensity data taken with the C-Band All Sky Survey (C-BASS) northern instrument at the Owens Valley Radio Observatory, California. Combining C-BASS maps with ancillary data to make temperature-temperature plots we find synchrotron spectral indices of β = −2.65±0.0...

A comparison of a 19 GHz full-sky map with the WMAP satellite K-band (23 GHz) map indicates that the bulk of the 20 GHz emission within 7 of the Galactic plane has an inverted (rising) spectrum with an average spectral index 1⁄4 0:21 0:05. While such a spectrum is inconsistent with steep-spectrum synchrotron ( 0:7) and flatspectrum free-free ( 0:1) emission, it is consistent with various models...