CALCULATING THE PARAMETERS USED IN TELLURIC CURRENT PROSPECTING

Geophysics ◽  
1963 ◽  
Vol 28 (3) ◽  
pp. 482-485 ◽  
Author(s):  
Li Y‐Shu
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Electrical Conductance ◽  
Sedimentary Basins ◽  
Base Station ◽  
Current Data ◽  
Field Station ◽  
Fixed Base ◽  
Station Location

In telluric current prospecting, the amplitudes of variations of the telluric‐electric field are measured simultaneously at a fixed base station and a roving field station. In sedimentary basins, variations in electrical conductance through the sedimentary column may be studied by comparing the amplitude of electric field variations at the roving station with the amplitude of the same electric field variations at the base station. The parameter ordinarily used in interpreting telluric current data is μ, the ratio of electric field intensity at a roving station location to the electric field intensity at the base station. Under favorable conditions, the ratio μ is directly proportional to the total longitudinal conductance of the rock layers above insulating basement rock.

TELLURIC SOUNDING—A MAGNETOTELLURIC METHOD WITHOUT MAGNETIC MEASUREMENTS

Geophysics ◽  
1966 ◽  
Vol 31 (1) ◽  
pp. 185-191 ◽  
Author(s):  
S. H. Yungul
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Magnetic Measurements ◽  
Sedimentary Basins ◽  
Base Station ◽  
Primary Objective ◽  
Field Station ◽  
Field Operation ◽  
Resistivity Log ◽  
The Magnetic Field

The basic theory and objectives of telluric sounding (TS) are about the same as those of the well‐known method of magnetotelluric sounding (MTS) (Cagniard, 1953). Both methods make use of the natural electromagnetic phenomena known as geomagnetic micropulsations to obtain crude “resistivity logs” from the surface down to great depths, without drilling, if the subsurface has mild structures, low dips, and lateral continuity in the electrical resistivity. Let the x-y plane of the Cartesian coordinates represent the surface of the earth. With MTS, the field operation consists of simultaneously recording the time variations of an arbitrary x component of the electric field, [Formula: see text], called a tellurogram, and that of the y component of the magnetic field, [Formula: see text], called a magnetogram, both at the same point where the downward information is desired. The main difficulty is in the measurement of the magnetic field variations with sufficient accuracy. The measurement of the electric field variations is very simple and expeditious. TS bypasses this difficulty, because it does not require the measurement of the magnetic field. With TS, the field operation requires two electric field recording units. One of these units remains at a “base station” where the subsurface is known from a well log, while the second unit is placed at a “field station” where one wishes to explore the subsurface. Thus, for each sounding, one obtains two simultaneous tellurograms. These are Fourier analyzed. The ratios of the electric field amplitudes as a function of frequency, combined with the resistivity log at the base station, furnish the MTS‐type data at the field station that are interpreted in the usual manner to yield a crude resistivity log at the field station. The primary objective of TS is the exploration of sedimentary basins. It may be preferable to MTS in certain cases and vice versa; it is not meant to replace MTS. The theoretical basis and the procedures of TS are discussed in this paper.

High-speed isotachophoresis. Analytical aspects of the steady-state longitudinal temperature profiles

1979 ◽  
Vol 44 (3) ◽  
pp. 841-853 ◽  
Author(s):  
Zbyněk Ryšlavý ◽  
Petr Boček ◽  
Miroslav Deml ◽  
Jaroslav Janák
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Minor Component ◽  
Physical Models ◽  
Temperature Profiles ◽  
Longitudinal Temperature ◽  
Continuous Character

The problem of the longitudinal temperature distribution was solved and the bearing of the temperature profiles on the qualitative characteristics of the zones and on the interpretation of the record of the separation obtained from a universal detector was considered. Two approximative physical models were applied to the solution: in the first model, the temperature dependences of the mobilities are taken into account, the continuous character of the electric field intensity at the boundary being neglected; in the other model, the continuous character of the electric field intensity is allowed for. From a comparison of the two models it follows that in practice, the variations of the mobilities with the temperature are the principal factor affecting the shape of the temperature profiles, the assumption of a discontinuous jump of the electric field intensity at the boundary being a good approximation to the reality. It was deduced theoretically and verified experimentally that the longitudinal profiles can appreciably affect the longitudinal variation of the effective mobilities in the zone, with an infavourable influence upon the qualitative interpretation of the record. Pronounced effects can appear during the analyses of the minor components, where in the corresponding short zone a temperature distribution occurs due to the influence of the temperatures of the neighbouring zones such that the temperature in the zone of interest in fact does not attain a constant value in axial direction. The minor component does not possess the steady-state mobility throughout the zone, which makes the identification of the zone rather difficult.

POLARON IN A QUANTUM DOT UNDER AN ELECTRIC FIELD

2007 ◽  
Vol 21 (24) ◽  
pp. 1635-1642
Author(s):  
MIAN LIU ◽  
WENDONG MA ◽  
ZIJUN LI
Keyword(s):  
Quantum Dot ◽  
Electric Field ◽  
Field Intensity ◽  
Ground State Energy ◽  
Ground State ◽  
Electric Field Intensity ◽  
State Energy ◽  
Theoretical Study ◽  
The Moment ◽  
Transformation Methods

We conducted a theoretical study on the properties of a polaron with electron-LO phonon strong-coupling in a cylindrical quantum dot under an electric field using linear combination operator and unitary transformation methods. The changing relations between the ground state energy of the polaron in the quantum dot and the electric field intensity, restricted intensity, and cylindrical height were derived. The numerical results show that the polar of the quantum dot is enlarged with increasing restricted intensity and decreasing cylindrical height, and with cylindrical height at 0 ~ 5 nm , the polar of the quantum dot is strongest. The ground state energy decreases with increasing electric field intensity, and at the moment of just adding electric field, quantum polarization is strongest.

scholarly journals Effects of Flash Sintering Parameters on Performance of Ceramic Insulator

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1157
Author(s):  
Yong Liu ◽  
Xingwang Huang
Keyword(s):  
Grain Size ◽  
Electric Field ◽  
Field Intensity ◽  
Current Density ◽  
Electric Field Intensity ◽  
Unit Cell ◽  
Uniform Structure ◽  
Ceramic Insulator ◽  
Flash Sintering ◽  
Ceramic Insulators

Ceramic outdoor insulators play an important role in electrical insulation and mechanical support because of good chemical and thermal stability, which have been widely used in power systems. However, the brittleness and surface discharge of ceramic material greatly limit the application of ceramic insulators. From the perspective of sintering technology, flash sintering technology is used to improve the performance of ceramic insulators. In this paper, the simulation model of producing the ceramic insulator by the flash sintering technology was set up. Material Studio was used to study the influence of electric field intensity and temperature on the alumina unit cell. COMSOL was used to study the influence of electric field intensity and current density on sintering speed, density and grain size. Obtained results showed that under high temperature and high voltage, the volume of the unit cell becomes smaller and the atoms are arranged more closely. The increase of current density can result in higher ceramic density and larger grain size. With the electric field intensity increasing, incubation time shows a decreasing tendency and energy consumption is reduced. Ceramic insulators with a higher uniform structure and a smaller grain size can show better dielectric performance and higher flashover voltage.

scholarly journals Frequency-Tunable Terahertz Plasmonic Structure Based on the Solid Immersed Method for Sensing

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1419
Author(s):  
Toshio Sugaya ◽  
Yukio Kawano
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Wavelength Region ◽  
Diffraction Limit ◽  
Field Analysis ◽  
Plasmonic Structure ◽  
Sensing Applications ◽  
Frequency Tunable ◽  
Bull's Eye

Terahertz waves are located in the frequency band between radio waves and light, and they are being considered for various applications as a light source. Generally, the use of light requires focusing; however, when a terahertz wave is irradiated onto a small detector or a small measurement sample, its wavelength, which is much longer than that of visible light, causes problems. The diffraction limit may make it impossible to focus the terahertz light down to the desired range by using common lenses. The Bull’s Eye structure, which is a plasmonic structure, is a promising tool for focusing the terahertz light beyond the diffraction limit and into the sub-wavelength region. By utilizing the surface plasmon propagation, the electric field intensity and transmission coefficient can be enhanced. In this study, we improved the electric field intensity and light focusing in a small region by adapting the solid immersion method (SIM) from our previous study, which had a frequency-tunable nonconcentric Bull’s Eye structure. Through electromagnetic field analysis, the electric field intensity was confirmed to be approximately 20 times higher than that of the case without the SIM, and the transmission measurements confirmed that the transmission through an aperture had a gap of 1/20 that of the wavelength. This fabricated device can be used in imaging and sensing applications because of the close contact between the transmission aperture and the measurement sample.

scholarly journals Frequency-Dependent FDTD Algorithm Using Newmark’s Method

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Bing Wei ◽  
Le Cao ◽  
Fei Wang ◽  
Qian Yang
Keyword(s):  
Differential Equation ◽  
Electric Field ◽  
Field Intensity ◽  
Time Domain ◽  
Difference Method ◽  
Electric Field Intensity ◽  
Polarization Vector ◽  
Solution Stability ◽  
Central Difference ◽  
Central Difference Method

According to the characteristics of the polarizability in frequency domain of three common models of dispersive media, the relation between the polarization vector and electric field intensity is converted into a time domain differential equation of second order with the polarization vector by using the conversion from frequency to time domain. Newmarkβγdifference method is employed to solve this equation. The electric field intensity to polarizability recursion is derived, and the electric flux to electric field intensity recursion is obtained by constitutive relation. Then FDTD iterative computation in time domain of electric and magnetic field components in dispersive medium is completed. By analyzing the solution stability of the above differential equation using central difference method, it is proved that this method has more advantages in the selection of time step. Theoretical analyses and numerical results demonstrate that this method is a general algorithm and it has advantages of higher accuracy and stability over the algorithms based on central difference method.

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