نتایج جستجو برای: electric frequency measurement
تعداد نتایج: 1021894 فیلتر نتایج به سال:
Recently through technique development of communication and information devices, the frequency used has come to extend into the gigahertz range. Especially, smaller probes of broadband with high-resolution are requested in the EMC field to measure and analyze devices. An optical electric field probe may present an accurate method for near-field measurement in the gigahertz range. In the present...
A long history of postmortem studies has provided significant insight into human brain structure and organization. Cadavers have also proven instrumental for the measurement of artifacts and nonneural effects in functional imaging, and more recently, the study of biophysical properties critical to brain stimulation. However, death produces significant changes in the biophysical properties of br...
This paper discusses the basic considerations and development of a prototype demo system for the wireless charging of supercapacitor electric vehicles, which uses magnetic resonance coupling. Considering future ubiquitous wireless vehicle stationary and dynamic charging facilities, supercapacitor could be an ideal device to store a reasonable amount of electrical energy for a relatively short p...
The described method allows the determination of velocity and attenuation variations introduced by low frequency alternating stresses and electric fields. Uniaxial stress is produced with a high load piezoelectric actuator and controlled with a strain gauge bridge. A modified impulse echo overlap system with a computer controlled sampling oscilloscope permits the measurement of very small effec...
Electrophoretic deposition of carbon nanotubes (CNTs) using alternating current electric fields (0.01-1000 Hz) is reported. Pure acetone was used as suspending medium. Two parallel gold electrodes were used as depositing substrate. The effect of depositing parameters such as frequency and three waveforms (sinusoidal, rectangular and triangular) on deposit yield was investigated. According to ou...
Free vibration of a simply-supported magneto-electro-elastic doubly-curved nano-shell is studied based on the first-order shear deformation theory in the presence of the rotary inertia effect. To model the electric and magnetic behaviors of the nano-shell, Gauss’s laws for electrostatics and magneto statics are used. By using Navier’s method, the partial differential equations of motion are red...
− In this paper a new Improved Recursive Newton Type Algorithm suitable for various measurement applications in electric power systems is presented. It is used for the power system frequency and spectra estimation. The recursive algorithm form is improved with a strategy of sequentially tuning of the forgetting factor. By this, the algorithm convergence and accuracy, are significantly improved....
Precise measurement of dielectric loss angle is very important for electric capacity equipment in recent power systems. When signal-to-noise is low and fundamental frequency is fluctuating, aiming at the measuring error of dielectric loss angle based on some recent Fourier transform and wavelet transform harmonics analysis method, we propose a novel algorithm based on sparse representation, and...
This paper provides a very brief overview of the capabilities and recent accomplishments of many of the low frequency electrical metrology projects at the National Institute of Standards and Technology. The projects presented here include the 5 main electrical measurement services projects (dc voltage, resistance, impedance, ac-dc difference, and electric power) and some electrical metrology re...
We study fluctuations of electric current in a quantum resistor and derive a general quantum-mechanical formula for the distribution of transmitted charge. For that we introduce a scheme of current measurement that involves a spin 1/2 coupled to the current so that it precesses at the rate proportional to the current. Our approach allows the study of charge transfer without breaking the circuit...
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