In-Plane Optical and Electrical Anisotropy of 2D Black Arsenic

ACS Nano ◽  
2020 ◽  
Author(s):  
Mianzeng Zhong ◽  
Haotong Meng ◽  
Sijie Liu ◽  
Huai Yang ◽  
Wanfu Shen ◽  
...  
Keyword(s):  
Electrical Anisotropy

Electrical Anisotropy of Thin Metal Films Growing on Dielectric Substrates

2002 ◽  
Vol 7 (2) ◽  
pp. 45-52
Author(s):  
L. Jakučionis ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Uniaxial Anisotropy ◽  
Metal Films ◽  
Thin Layers ◽  
Electrical Anisotropy ◽  
Electrical Field ◽  
Dielectric Substrates ◽  
Unequal Probability ◽  
Conductive Thin Films

Electrical properties of conductive thin films, that are produced by vacuum evaporation on the dielectric substrates, and which properties depend on their thickness, usually are anisotropic i.e. they have uniaxial anisotropy. If the condensate grow on dielectric substrates on which plane electrical field E is created the transverse voltage U⊥ appears on the boundary of the film in the direction perpendicular to E. Transverse voltage U⊥ depends on the angle γ between the applied magnetic field H and axis of light magnetisation. When electric field E is applied to continuous or grid layers, U⊥ and resistance R of layers are changed by changing γ. It means that value of U⊥ is the measure of anisotropy magnitude. Increasing voltage U0 , which is created by E, U⊥ increases to certain magnitude and later decreases. The anisotropy of continuous thin layers is excited by inequality of conductivity tensor components σ0 ≠ σ⊥. The reason of anisotropy is explained by the model which shows that properties of grain boundaries are defined by unequal probability of transient of charge carrier.

scholarly journals Magnetotelluric study in the Los Lagos Region (Chile) to investigate volcano-tectonic processes in the Southern Andes

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Maria Jose Segovia ◽  
Daniel Diaz ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Phase Changes ◽  
Fault System ◽  
Electrical Anisotropy ◽  
Mountain Range ◽  
Southern Andes ◽  
Nazca Plate ◽  
First Results ◽  
Dimensional Parameters

AbstractTo analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data-processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1 s and two-dimensional for periods greater than 10 s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80–100 km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.

Extracardiac effects of myocardial electrical anisotropy

2001 ◽  
Vol 46 (s2) ◽  
pp. 216-218 ◽  
Author(s):  
B. Taccardi ◽  
B.B. Punske ◽  
R.S. MacLeod ◽  
Q. Ni
Keyword(s):  
Electrical Anisotropy

A Novel Workflow for Geosteering a Horizontal Well in a Low Resistivity Contrast Anisotropic Environment: A Case Study in Semoga Field, Indonesia

2021 ◽  
Author(s):  
Yessica Fransisca ◽  
Karinka Adiandra ◽  
Vinda Manurung ◽  
Laila Warkhaida ◽  
M. Aidil Arham ◽  
...  
Keyword(s):  
Real Time ◽  
Horizontal Well ◽  
Gamma Ray ◽  
Lessons Learned ◽  
Electrical Anisotropy ◽  
Anisotropy Ratio ◽  
Well Placement ◽  
Low Contrast ◽  
Low Resistivity ◽  
The Subject

Abstract This paper describes the combination of strategies deployed to optimize horizontal well placement in a 40 ft thick isotropic sand with very low resistivity contrast compared to an underlying anisotropic shale in Semoga field. These strategies were developed due to previously unsuccessful attempts to drill a horizontal well with multiple side-tracks that was finally drilled and completed as a high-inclined well. To maximize reservoir contact of the subject horizontal well, a new methodology on well placement was developed by applying lessons learned, taking into account the additional challenges within this well. The first approach was to conduct a thorough analysis on the previous inclined well to evaluate each formation layer’s anisotropy ratio to be used in an effective geosteering model that could better simulate the real time environment. Correct selections of geosteering tools based on comprehensive pre-well modelling was considered to ensure on-target landing section to facilitate an effective lateral section. A comprehensive geosteering pre-well model was constructed to guide real-time operations. In the subject horizontal well, landing strategy was analysed in four stages of anisotropy ratio. The lateral section strategy focused on how to cater for the expected fault and maintain the trajectory to maximize reservoir exposure. Execution of the geosteering operations resulted in 100% reservoir contact. By monitoring the behaviour of shale anisotropy ratio from resistivity measurements and gamma ray at-bit data while drilling, the subject well was precisely landed at 11.5 ft TVD below the top of target sand. In the lateral section, wellbore trajectory intersected two faults exhibiting greater associated throw compared to the seismic estimate. Resistivity geo-signal and azimuthal resistivity responses were used to maintain the wellbore attitude inside the target reservoir. In this case history well with a low resistivity contrast environment, this methodology successfully enabled efficient operations to land the well precisely at the target with minimum borehole tortuosity. This was achieved by reducing geological uncertainty due to anomalous resistivity data responding to shale electrical anisotropy. Recognition of these electromagnetic resistivity values also played an important role in identifying the overlain anisotropic shale layer, hence avoiding reservoir exit. This workflow also helped in benchmarking future horizontal well placement operations in Semoga Field. Technical Categories: Geosteering and Well Placement, Reservoir Engineering, Low resistivity Low Contrast Reservoir Evaluation, Real-Time Operations, Case Studies

Cr-Al2O3 layered composites with a high electrical anisotropy prepared by repeated deformation processing

2005 ◽  
Vol 25 (1) ◽  
pp. 65-72 ◽  
Author(s):  
M. Leverkoehne ◽  
Aleš Dakskobler ◽  
M. Valant ◽  
R. Janssen ◽  
Tomaž Kosmač
Keyword(s):  
Electrical Anisotropy ◽  
Layered Composites ◽  
Deformation Processing

scholarly journals Analysis of filtration and electrical properties anisotropy of terrigenous reservoir rocks (for DDB axial zone reservoirs)

2019 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Gas Permeability ◽  
Vertical Direction ◽  
Absolute Permeability ◽  
Electrical Anisotropy ◽  
Reservoir Rocks ◽  
Vertical Permeability ◽  
Irreducible Water Saturation ◽  
Horizontal Permeability ◽  
Filtration Properties

The paper focuses on the filtration and electrical anisotropy coefficients and relationship between vertical and horizontal permeability in sandstone reservoir rocks. Field case study of DDB reservoir rocks. Petrophysical properties and parameters are estimated from core and log data from a Moscovian and Serpukhovian stages of Dnipro-Donetsk Basin (West-Shebelynka area well 701-Bis and South-Kolomak area well 31). Routine core analysis included estimation of absolute permeability, open porosity, irreducible water saturation and electrical resistivity (on dry and saturated by mineralized solution) of 40 core samples along two orthogonal directions. Shale fraction is estimated using well logging data in wells which are analyzed. The authors report that reservoir rocks are represented by compacted poor-porous (φ <10 %), low permeable (k<1mD) laminated sandstone with different ratios of clay minerals (Vsh from 0,03 to 0,7) and high volume of micaceous minerals (in some cases 20-30 %). Research theory. One of the main objectives of the work is to develop empirical correlation between vertical permeability and other capacitive and filtration properties for compacted sandstone reservoirs. A modified Kozeny-Carman equation and the concept of hydraulic average radius form the basis for the technique. Results. Coefficients of the anisotropy of gas permeability (IA) and electrical resistivity (λ) are defined based on the results of petrophysical studies. The experiments proved that IA lies in a range from 0,49 to 5 and λ from 0,77 to 1,06. Permeability and electrical resistivity anisotropy in most cases have horizontal distribution. It has been shown that in West-Shebelynka area sample №1 (depth 4933 m) there is probably no fluids flow in vertical direction and in samples №№3 and 15 fractures have the vertical orientation. We have also found that the values of electrical and filtration anisotropy for all samples of South-Kolomak area are similar, this characterized the unidirectionality in their filtration properties, as well as the fact that the motion of the fluid flow mainly in the horizontal direction. In the studied rocks the degree of anisotropy has been concluded to depend on the volume of clay and micaceous minerals, their stratification, fractures, density, and their orientation. New correlation between vertical permeability, horizontal permeability and effective porosity are developed for Late Carboniferous DDB intervals that are analyzed.

scholarly journals A THREE-PHASE INDUCTIVE SENSOR FOR IN VIVO MEASUREMENT OF ELECTRICAL ANISOTROPY OF BIOLOGICAL TISSUES

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Yukio Kosugi ◽  
Tadashi Takemae ◽  
Hiroki Takeshima ◽  
Atsushi Kudo ◽  
Kazuyuki Kojima ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
High Frequency ◽  
Reference Signal ◽  
Biological Tissues ◽  
Electrical Anisotropy ◽  
Conductivity Anisotropy ◽  
In Vivo Measurement ◽  
Surgical Operations

Biological tissue will have anisotropy in electrical conductivity, due to the orientation of muscular fibers or neural axons as well as the distribution of large size blood vessels. Thus, the in vivo measurement of electrical conductivity anisotropy can be used to detect deep-seated vessels in large organs such as the liver during surgeries. For diagnostic applications, decrease of anisotropy may indicate the existence of cancer in anisotropic tissues such as the white matter of the brain or the mammary gland in the breast. In this paper, we will introduce a new tri-phase induction method to drive rotating high-frequency electrical current in the tissue for the measurement of electrical conductivity anisotropy. In the measurement, three electromagnets are symmetrically placed on the tissue surface and driven by high-frequency alternative currents of 0 kHz, modulated with 1 kHz 3-phase signals. In the center area of three magnets, magnetic fields are superimposed to produce a rotating induction current. This current produces electrical potentials among circularly arranged electrodes to be used to find the conductivity in each direction determined by the electrode pairs. To find the horizontal and vertical signal components, the measured potentials are amplified by a 2ch lock-in amplifier phase-locked with the 1 kHz reference signal. The superimposed current in the tissue was typically 45 micro Amperes when we applied 150 micro Tesla of magnetic field. We showed the validity of our method by conducting in vitro measurements with respect to artificially formed anisotropic materials and preliminary in vivo measurements on the pig’s liver. Compared to diffusion tensor MRI method, our anisotropy sensor is compact and advantageous for use during surgical operations because our method does not require strong magnetic field that may disturb ongoing surgical operations.

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