An Optimal Electric Dipole Antenna Model and Its Field Propagation

An optimal electric dipole antennas model is presented and analyzed, based on the hemispherical grounding equivalent model and the superposition principle. The paper also presents a full-wave electromagnetic simulation for the electromagnetic field propagation in layered conducting medium, which is excited by the horizontal electric dipole antennas. Optimum frequency for field transmission in different depth is carried out and verified by the experimental results in comparison with previously reported simulation over a digital wireless Through-The-Earth communication system. The experimental results demonstrate that the dipole antenna grounding impedance and the output power can be efficiently reduced by using the optimal electric dipole antenna model and operating at the optimum frequency in a vertical transmission depth up to 300 m beneath the surface of the earth

Investigation of the process of strong acoustic signal propagation in a layered environment of ice-water-bottom

A mathematical model was developed to calculate acoustic wave in a shallow sea under an ice layer for low frequency signals of 40-150 Hz. An experimental unit was developed by the authors on the basis of a low-frequency piston-type electrodynamic radiator which is capable of making experiments in layered environment. The experiments show satisfactory agreement with theoretical investigations. The peculiarities of wave propagation at water-ice boundary are under investigation. The developed models may be applied for new engineering systems for earthquake forecast when installing receiving systems in an ice layer

Investigation of acoustic fields in the arctic zone with uneven ice cover

A mathematical model for elastic wave propagation in an ice cover with uneven relief (hummock) has been developed. The theoretical model is based on the application of “directed” Green’s functions. We obtained numerical results for different distances between radiating and receiving antennas installed inside the ice layer and in water medium. An information-measuring system was created to investigate elastic acoustic waves along ice surface based on electo-hydraulic generator. Experiments of high-frequency acoustic signal propagation from electro-hydraulic generator in water-ice-air system were carried out. We illustrated the model validity for the investigation of hydroacoustic wave propagation in real ice conditions

Interaction of electromagnetic waves in an ice layer

A mathematical model for spherical wave propagation near an ice layer has been developed. The proposed mathematical model is based on the directed Green’s functions with boundary conditions with irregular angles. Based on the suggested model, we analyzed a field of a point directed source radiating electromagnetic waves in two cases: the source is in the air and is radiating waves along the marine ice surface; the source is in the ice layer and radiating waves. Results of the modeling for different frequencies and different ice thickness are described. It was shown that wave amplitude increases by about two times inside the ice if compared to free space. Electromagnetic wave propagating along marine ice surface increases by 50% compared to the wave propagating in free space

Interaction of elastic waves with ice layer in shelf zone

A theoretical model for the propagation of elastic waves of arbitrary wave sizes from 0.5 to 20 units in an ice layer has been developed. The calculation was based on Green’s function theory for Helmholtz equation. Special “directed” Green’s functions were introduced. They make it possible to anayze wave fields in closes volumes limited by different-angle impedances. The developed calculation algorithms allow one to anayze fields on medium-powered computers for 15 minutes. The suggested methods are capable of estimating elastic wave interactions with different impedances in bays, lakes and other volumes with limited wave sizes

Investigation of electromagnetic fields in the arctic zone with uneven ice cover

Numerical investigation of electromagnetic waves propagating near an ice cover with hummocks of different height has been carried out. Half-wave vibrators, melted into ice at the depth of about 20 sm, were used as an antenna. Transmitted signal frequencies were from 10 to 30 MHz. A mathematical model for amplitude spatial distribution of electromagnetic wave source, placed inside an ice cover with hummocks, was developed. The results of numerical study show that, when antenna is inside hummocks, the signal is amplified. Experimental investigations show good agreement with the theoretical model

Investigation of the channel for information transfer by electric, electromagnetic and acoustic waves in layered environment with ice cover

A theoretical model of electromagnetic wave propagation in an ice layer was developed. A half-wave vibrator frozen in an ice layer is used as a receiving-radiating system of electromagnetic waves. Schemes of developed acoustic low-frequency radiators based on electric sparks are described. The possibility of application of the developed systems to receive acoustic signals from earthquake ice source is under discussion

Electrochemical Properties of Bismuth Oxide Films on Titanium Formed by Plasma Electrolytic Oxidation

На поверхности титана методом плазменно-электролитического оксидирования (ПЭО) сформированы висмутосодержашие оксидные покрытия из электролитов, содержащих комплексные ионы ЭДТА-Bi3+. Определены электрохимические характеристики – токи обмена, коэффициенты переноса α и β, коэффициенты a и b в уравнении Тафеля. Для полученных систем установлено возникновение аналитического сигнала при комплексонометрическом титровании солей железа (III). Рядом физических методов (сканирующая электронная микроскопия с энергодисперсным анализом и рентгеновская фотоэлектронная спектроскопия) изучены морфология и состав поверхности оксидных покрытий. Найдена корреляция между морфологией, составом поверхности и электрохимическими свойствами образцовBismuth oxide layers on a titanium are formed by a plasma electrolytic oxidation (PEO) method from electrolytes containing complex ions EDTA-Bi3+. Electrochemical characteristics – exchange currents, transport coefficients α and β, a and b coefficients in Tafel’s equation are defined. For the obtained systems occurrence of an analytical signal at complexometric titration of salts of Fe (III) is established. The structural features of surface electrodes have been investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. Correlation between morphology, structure of a surface and electrochemical properties of samples is foun

Electronic Structure of NdFeCoB Oxide Magnetic Particles Studied by DFT Calculations and XPS

Neodymium-iron-boron magnetic oxide powders synthesized by sol–gel Pechini method were studied by using X-ray photoelectron spectroscopy (XPS) and quantum chemical modeling. The powder structure was examined by using X-ray diffraction (XRD) and modeled by using density functional theory (DFT) approximation. The electronic structures of the core and valent regions were determined experimentally by using X-ray photoelectron spectroscopy and modeled by using quantum chemical methods. This study provides important insights into the electronic structure and chemical bonding of atoms of NdFeCoB oxide particles with the partial substitution of Fe by Co atoms

Electrochemical Properties of Bismuth Oxide Films on Titanium Formed by Plasma Electrolytic Oxidation

На поверхности титана методом плазменно-электролитического оксидирования (ПЭО) сформированы висмутосодержашие оксидные покрытия из электролитов, содержащих комплексные ионы ЭДТА-Bi3+. Определены электрохимические характеристики – токи обмена, коэффициенты переноса α и β, коэффициенты a и b в уравнении Тафеля. Для полученных систем установлено возникновение аналитического сигнала при комплексонометрическом титровании солей железа (III). Рядом физических методов (сканирующая электронная микроскопия с энергодисперсным анализом и рентгеновская фотоэлектронная спектроскопия) изучены морфология и состав поверхности оксидных покрытий. Найдена корреляция между морфологией, составом поверхности и электрохимическими свойствами образцовBismuth oxide layers on a titanium are formed by a plasma electrolytic oxidation (PEO) method from electrolytes containing complex ions EDTA-Bi3+. Electrochemical characteristics – exchange currents, transport coefficients α and β, a and b coefficients in Tafel’s equation are defined. For the obtained systems occurrence of an analytical signal at complexometric titration of salts of Fe (III) is established. The structural features of surface electrodes have been investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. Correlation between morphology, structure of a surface and electrochemical properties of samples is foun