We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr₀.₅₂Ti₀.₄₈)O₃ (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC voltage. The curvature of the diaphragm was controlled by applying air pressure to its back. We found that a depolarized flat diaphragm does not initia...

As the remedy used music becomes active and meditation effect through the music is verified, people take a growing interest about psychological balance or remedy given by music. From traditional studies, it is verified that the music of which spectral envelop varies approximately as 1/f (f is frequency) down to a frequency of low frequency bandwidth gives psychological balance. In this paper, w...

In this paper, we show that an $L_1$-2-type surface in the three-dimensional hyperbolic space $H^3subset R^4_1$ either is an open piece of a standard Riemannian product $ H^1(-sqrt{1+r^2})times S^{1}(r)$, or it has non constant mean curvature, non constant Gaussian curvature, and non constant principal curvatures.

materials and methods: one hundred and thirty five mesial root canals of mandibular first and second molar teeth were selected. access cavities were prepared. after inserting a k-file size #10 into each canal, radiographs were taken. canal curvature was determined by measuring the schneider angle, canal access angle, as well as the canal radius, length, height and curvature starting distance on...

i ntroduction: the aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. methods and materials: mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25 ° and 35 ° and radii of curvature from 5 to 9 mm, were divided into three groups ( n =40). in...

When considering perturbations in an open universe, cosmologists retain only subcurvature modes (defined as eigenfunctions of the Laplacian whose eigenvalue is less than −1 in units of the curvature scale, in contrast with the super-curvature modes whose eigenvalue is between −1 and 0). Mathematicians have known for almost half a century that all modes must be included to generate the most gene...

Through of the concept of curvature energy encoded in non-harmonic signals due to the effect that characterizes the curvature as a deformation of field in the corresponding resonance space ( and an obstruction to the displacement to the corresponding shape operator) is developed and designed a sensor of quantum gravity considering the quantized version of curvature as observable of gravitationa...

although, most of the abnormal structures of human brain do not alter the shape of outer envelope of brain (surface), some abnormalities can deform the surface extensively. however, this may be a major problem in a surface-based registration technique, since two nearly identical surfaces are required for surface fitting process. a type of verification known as the circularity check for the shap...

introduction: the objective of this study was to compare the shaping ability of three rotary filing systems; constant taper k3 instruments, constant taper profile instruments and progressive taper protaper rotary instruments in clear resin blocks with simulated curved root canals. materials and methods: forty five resin blocks were divided into three groups. group a preparation was conducted wi...

The reduced Ostrovsky equation is a modification of the Korteweg-de Vries equation, in which the usual linear dispersive term with a third-order derivative is replaced by a linear non-local integral term, which represents the effect of background rotation. This equation is integrable provided a certain curvature constraint is satisfied. We demonstrate, through theoretical analysis and numerical...