Square Of Electric Field Research Articles

Electromechanical properties of PMN-PT thin films prepared by pulsed laser deposition technique

Ferroelectric relaxor thin films of the composition 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 (PMN-PT) were fabricated by pulsed laser deposition technique on Pt/Ti/SiO2/Si(100) substrates using a La0.5Sr0.5CoO3 film as a template layer. The films were polycrystalline with random orientation of the grains. Electromechanical properties of the films were evaluated by a sensitive interferometric technique as a function of the dc and ac electric fields and frequency. Experimental results show that the effective piezoelectric coefficient d33 can be tuned over a wide range of magnitudes by varying dc bias fields. A small hysteresis and a low remanent d33 were observed, which favor the use of PMN-PT films in electric field-controlled micromechanical devices. The maximum d33 ranged from 50 to 100 pm/V, depending on the thickness of the films and frequency. The piezoelectric properties are explained based on the expression for the electrostriction biased by polarization. At low electric field, strain is proportional to the square of electric field, while at higher fields it can be better described as the polarization squared. The asymmetry of the strain response in PMN-PT films is attributed to the polarization offset appearing due to the different electrode materials.

Determining the radiofrequency dipole and quadrupole effects in quarter wave resonators

The asymmetry of a quarter wave resonator (QWR) around the beam axis z causes deflection and additional (de)focusing of the beam: these effects are immediately related to the first terms, the dipole and the quadrupole, in a Fourier-Bessel multipole expansion of the quasistatic potential φ; the non-relativistic impulse approximation for heavy ion acceleration is given. General features of multipole dependencies from beam phase and velocities are shown. Since the electric field square modules | E| 2 is measurable with the bead technique, an iterative determination of E x and E y from E z and the potential φ is proposed here; the noise contribution is not amplified at the shortest wavelength Fourier components, and it can be filtered. Field errors are reduced by imposing the fit to the correct analytic form inside the drift tubes, where the fields exponentially decrease. The preliminary set of data relative to a QWR with an ogiva central rod is treated as an example, showing that dipole effects have a zero near the beam velocities optimal for acceleration.

Interface scattering as a source for diffuse interference in cuprous oxide on copper

Interference in the diffuse reflectance (IDR) from thermally oxidized copper is considered. It is demonstrated that the diffuse reflectance scales with the value of the time-averaged square of electric field, 〈 E 2〉 at the oxide/metal interface. The appearance of IDR is therefore a sensitive probe of interface roughness created by the oxidation.

Electrophysiological evidence of electroreception in the axoloyl Siredon mexicanum

Single unit recordings from a branch of the anterior lateral line nerve of the axolotl Siredon mexicanum, reveal the existence of two types of afferents. One type reacts to electric field square pulses below 100 μV/cm and is insensitive to weak mechanical stimuli. The other type is very sensitive to water displacements and can only be excited by electric square pulses above 3 mV/cm. We consider the fiber population with low electric thresholds to originate from electrosensitive receptors and the second population to represent fibers from ordinary mechanosensitive lateral line organs.

Soltents effects on nmr spectra of gases and liquids

Soltents effects on nmr spectra of gases and liquids

Application of Regge Calculus to the Schwarzschild and Reissner-Nordstro/m Geometries at the Moment of Time Symmetry

Applied to 3-dimensional space, Regge calculus approximates a curved space by a collection of tetrahedrons or other simple solid blocks. Within each block the geometry is Euclidean. Curvature is idealized as concentrated at the edge common to two or more of these solids. We specialize to a static geometry endowed with spherical symmetry and to a radial electric field produced by the flux of electric lines of force trapped in a throat connecting two quasi-Euclidean regions of space. The one relevant Einstein field equation takes the form ∑ all edges which meet at a given vertex(length of edge of prism)(deficit between (1) sum of dihedral angles which meet at that edge and (2) normal value of 2π)=(factor proportional to square of electric field). In method (1) the space is decomposed into shells separated from one another by icosahedral surfaces, all having a common center. Method (2) is even simpler: Space is decomposed into successive spherical shells of area 4π ρi2 separated by a proper distance d. Regge calculus gives a recurrence relation relating the dimensions of the successive shells. The approximate geometries calculated by methods (1) and (2) are compared with the well-known exact Schwarzschild and Reissner-Nordstro/m geometries. Errors range from roughly 10% down to less than 1%, depending upon the method of analysis, the quantity under analysis, and the fineness of the subdivision.