This paper presents novel micromachined two-dimensional array piezoelectrically actuated flextensional transducers that can be used to generate sound in air or water. Micromachining techniques to fabricate these devices are also presented. Individual unimorph array elements consist of a thin piezoelectric annular disk and a thin, fully clamped, circular plate. We manufacture the transducer in t...

A tangent linear adjoint for a low-resolution dynamical model of the atmosphere is used to derive the optimal forcing perturbations for all state variables such that after a specified lead time the model response has a given projection, in terms of an energy norm, on the pattern associated with the 51-yr trend in the Northern Hemisphere winter tropospheric circulation, 1948/49–1998/99. A featur...

rabbitfish is economically valuable teleost species which lives in shallow coastalwaters. two species of rabbit fish have been recognized in southern sea of iran (persiangulf) as namely siganus sutor and siganus javus. in the current study, in order toinvestigate the histology of the annular ligament of the s. javus’ eye, the prepared sectionsof the eyes of twelve healthy specimens were studied...

The term "Arctic Oscillation" (AO) has recently been introduced to describe the leading structure of SLP variability over the Northern Hemisphere. A key feature of the AO is its zonally symmetric appearance, with a primary center of action over the Arctic and opposing anomalies in midlatitudes. Does the AO's annular appearance result from significant temporal correlations between SLP anomalies ...

Abstract We propose a new kind of compound optical vortex (COV) generator in this paper. The device consists an inner spiral phase plate (SPP) and outer annular plate. There is opaque band between two SPPs. Under the flat-top beam irradiation, concentric multi-ring COV rings with different topological charges radial radii can be generated. theoretical analysis lays foundation for design generat...

Repulsion, induced from quantum vacuum fluctuations, for an anisotropically polarizable atom on the symmetry axis of annular disc is studied. There exists two torsion free points each side disc, where interaction energy orientation independent. The position second points, either shown to determine dependence at distances far plate, revealing a geometrical dependence. In ring limit new repulsion...

This work proposes a small pattern and polarization diversity multi-sector annular antenna with electrical size profile of ka = 1.2 0.018λ, respectively. The is planar comprises sectors that are fed using different ports to enable digital beamforming techniques, efficiency gain up 78% 4.62 dBi,...