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Modeling of Micro- and Nanoscale Electromechanical Systems, Devices, and Structures
Published in Sergey Edward Lyshevski, Mems and Nems, 2018
Simplifying the analysis, we consider the transverse effect in the rectangular piezoelectric film, see Figure 5.6.2. The first (1) and second (2) axes define a plane which is parallel to the film surface, while the third (3) axis is perpendicular to the surface (third axis points in the opposite direction to the electric field applied to pole the piezoelectric films). The film length, width, and thickness are within the first, second and third axes, respectively. A voltage is measured (or applied) across the upper and lower electrodes, which have free charges +q and –q. A tensile force f1 and an elongation displacement y1 are measured along the first axis. It must be emphasized that if piezoelectric films are used as actuators, a voltage V3 is applied across the film, and the induced polarization in the piezoelectric generates a tensile force f1 and a displacement y1. If piezoelectric films are used as sensors, a tensile force f1 is applied stretching the film by y1, and the induced polarization in the piezoelectric causes an increase of free charges generating a voltage V3.
Modeling of Micro- and Nanoscale Electromechanical Systems and Devices
Published in Sergey Edward Lyshevski, Nano- and Micro-Electromechanical Systems, 2018
Simplifying the analysis, we consider the transverse effect in the rectangular piezoelectric film. (See Figure 6.76.) The first (1) and second (2) axes define a plane that is parallel to the film surface, while the third (3) axis is perpendicular to the surface. (Third axis points in the opposite direction to the electric field applied to pole the piezoelectric films.) The film length, width, and thickness are within the first, second, and third axes, respectively. A voltage is measured (or applied) across the upper and lower electrodes, which have free charges +q and -q. A tensile force f1 and an elongation displacement y1 are measured along the first axis. It must be emphasized that if piezoelectric films are used as actuators, a voltage V3 is applied across the film, and the induced polarization in the piezoelectric generates a tensile force f1 and a displacement y1. If piezoelectric films are used as sensors, a tensile force f1 is applied, stretching the film by y1, and the induced polarization in the piezoelectric causes an increase of free charges generating a voltage V3.
Petroleum Geo-Electrical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
In the internal chemical circuit the electrodes are immersed in an electrolyte solution contained in a cell. Under the influence of an external current, ionization (decomposition) of the mineral present in the electrolyte takes place into cations and anions. The electrochemical decomposition of ionic material creates its own current and electromotive force (EMF). An internal cell current flows from cathode to anode through the ion exchange process. Anions generated at the cathode, with an excess electron, travel to the anode. At the anode electrons are delivered to cause the current to flow externally. At the same time the anode generates cations that are transferred to the opposite direction through the electrolyte solution. Finally cations are deposited at the cathode. Ions are deposited at each electrode in equilibrium conditions. When such equilibrium is disturbed, this results in an uneven distribution of ions. A lesser or greater concentration of ions is found on one or the other electrode. Such a condition is known as ‘over voltage’. Over voltage is the difference between the theoretical value (equilibrium) of the current and the excess current needed to drive the current. The electrode with excess ions is ‘polarized’ and the phenomenon is known as ‘induced polarization’. Current at over voltage value is called the ‘saturation current’. A polarized electrode acts like an electrical capacitor. A capacitor (condenser) temporarily stores electric charge in an electrical circuit. A polarized electrode continues to release storage energy (current) even after the current switch is turned off. The stored charge gradually decays over a period of time.
Laboratory core investigations of sandstone-hosted uranium for in situ recovery
Published in Applied Earth Science, 2020
Micha Zauner, Andreas Weller, Matthias Halisch
Spectral induced polarization (SIP) measures the frequency-dependent (i.e. spectral) impedance amplitude and phase shift between electric current and voltage. The usual frequency range for alternating current (AC) applied during SIP surveys extends from millihertz to kilohertz. The method has long been established as a field survey in the mineral exploration industry and is applied at a lab scale for the present purpose (e.g. the seminal work of Wait (1982) or the comprehensive review by Luo and Zhang (1998) or Kemna et al. (2012)).
Limits to remote molecular detection via coherent anti-Stokes raman spectroscopy using a maximal coherence control technique
Published in Journal of Modern Optics, 2020
Gengyuan Liu, Frank A Narducci, Svetlana A Malinovskaya
Based on a semiclassical approach, we estimated the feasibility of FAST CARS for a real-time remote detection of hazardous microparticles in atmosphere. We also evaluated the range of distances for typical species based on the parameters of a typical laser system that drive the limits. We rely on a semiclassical theory of nonlinear scattering introduced in (16) to estimate the number of detectable photons from molecules at a predetermined distance. In (16), the integral solution of the nonlinear scattering by the particle is obtained from the inhomogeneous vector wave equation with the right side in the form of induced polarization as a source to generate the CARS signal. Reflection and refraction due to the linear response of the signal are implicitly accounted for in the anti-Stokes coherence obtained from the Bloch equations. The Lorenz-Mie theory is implemented to study the inhomogeneous spatial distributions on the incident fields as the results of refraction and internal reflection in a single bacterial spore. The strength of the backward signal from a single spore was estimated by plotting the anti-Stokes signal as a function of observation angle, Figure 3 in (16). It shows that the backscattered signal is almost as strong as the forward signal. The ratio of the signal intensity to probe intensity is plotted for inhomogeneous fields within the spore due to lensing and focusing by the spore. For remote molecular detection, the situation in the detection area that contains target molecules could be extremely complex. For example, detection target could be tiny droplets of molecules, or just an open area containing molecules. In the droplets case, a similar response could be expected as for the anthrax, because a tiny droplet having the size similar to the probing wavelength would interact with the field similarly to a single spore. In the second, the homogeneous case of a dense cloud of molecules, the theory in (16) can be used to provide a sufficiently meaningful magnitude of detectable signal, even though the phase matching condition is tight (17).
Temperature dependence on ferroelectric properties and strain performance of PLZT ceramics containing 9 mol% La
Published in Phase Transitions, 2020
Narit Funsueb, Apichart Limpichaipanit, Athipong Ngamjarurojana
PLZT 9/xZr/100-xTi powders where x = 70, 65, 60, 55 and 50 mol% were prepared by mixed-oxide method. All powders were weighed, mixed and milled by vibro-milling (McCrone Micronizing Mill) for 30 minutes with a corundum cylindrical media in ethanol. After drying at 120°C for 24 h, the mixture of oxides was calcined at 900°C for 2 h in air. Green pellets of 10.0 mm diameter were prepared using uniaxial-pressure of 200 MPa. The pellets were then placed in a high purity alumina crucible and two-stage sintered at 1275°C for 4 h and then at 1200°C for 2 h in air. To prevent PbO loss and to maintain the desirable Zr/Ti ratios, the samples were in the closed crucible during sintering. The sintered samples were polished, cleaned and screen printed with silver electrodes. The XRD patterns at room temperature were recorded by X-ray diffraction (Rigaku model MiniFlex II). The CuKα radiation was used as X-ray source. After XRD pattern fitting, quantitative analysis was performed to determine lattice parameters, unit cell volume, tetragonality and amount of each phase in case of phase coexistence. Scanning electron microscopy (SEM) was used to determine average grain size by fracture surface. Dielectric properties (dielectric constant and dielectric loss at 1, 10 and 100 kHz) were studied as a function of temperature range of 40–250°C with the computer-controlled dielectric measurement system consisting of a LCR device (Tonghui TH2829C), a heating chamber and a computer control system. Electric field induced polarization and strain behavior were investigated at the constant frequency of 5 Hz and various electric field strengths by a modified Sawyer-Tower circuit with strain measurement system, which consists of linear variable differential transformer (LVDT), DSP lock-in amplifier (SR850, Stanford Research), high voltage power supply (TREK610C, Trek) and detected signal by digital oscilloscope with computer programs (PicoScope 400 series). The modified strain measuring system with temperature control system consists of thermoelectric temperature controller (Newport 300), and temperature sensor whereas the room temperature (25°C) and the temperature range of 30–140°C with a step of 10°C were used.