scholarly journals GEOLOGICAL INFORMATION OF MAGNETIC PROPERTIES OF GRANITOIDS OF THE PRECEMBRIAN BASEMENT OF UKRAINIAN SHIELD (ON THE EXAMPLE OF THE MELNIKOVTSY PLOT)

2021 ◽  
Vol 7 (2(38)) ◽  
pp. 33-41
Author(s):  
M. Reshetnyk ◽  
D. Starokadomsky
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Internal Structure ◽  
Geophysical Methods ◽  
Geological Mapping ◽  
The Body ◽  
Ukrainian Shield ◽  
Scanning Method ◽  
Geological Body ◽  
The Magnetic Field

In Ukraine, there are all possibilities for the development of geophysical methods for solving the problems of mapping the Precambrian foundation, as there is a well-exposed Ukrainian Shield (US). The article shows the possibilities of the magnetic scanning method for geological mapping, on the example of a section composed of granitoids with xenoliths of crystalline shales. The magnetic field and magnetic susceptibility on exposures are «scanned» in detail. Two positive anomalies of the magnetic field with a similar fine internal structure have been identified. The results of the study showed that granitoids have low magnetic properties that do not allow the formation of positive anomalies of the magnetic field. It is assumed that the source of «toothed» positive anomalies of the magnetic field in the studied section of the US can be two parts of one layered geological body — with a rhythmic internal structure composed of crystalline shales. It is possible that the body was awakened by local tectonic processes and torn into parts that are significantly displaced, and even lie almost parallel in the study area.

scholarly journals INVESTIGATION MAGNETIC FIELD AND ROCK MAGNETISM DIVERSITY OF THE MELNYKOVTCI PLOT OF THE UKRAINIAN SHIELD

2020 ◽  
Author(s):  
M. Reshetnyk ◽  
D. Starokadomsky ◽  
C. Popov ◽  
R. Khomenko
Keyword(s):  
Magnetic Field ◽  
Rock Magnetism ◽  
Residual Magnetization ◽  
Ukrainian Shield ◽  
Southwestern Part ◽  
Scanning Method ◽  
Local Tectonics ◽  
Thermomagnetic Properties ◽  
The Magnetic Field

The magnetic scanning method was used to study the exposed section of the Ukrainian Shield in its southwestern part (Pobuzhie region). The values of induction T of the magnetic field (49750+– 100 nT, not counting on the global field), and the magnetic susceptibility MS indices “in situ” were determined. It was found that the MS values vary in 0 - 50 • 10-3 u.SI, with the presence of single regions of more than 50 • 10-3 u.SI. Not found regular direct correlations and patterns of changes in the indicators MS and T. An attempt has been made to reveal correlations between fluctuations of the magnetic field and MS-differences. The results are interpreted from the standpoint of local tectonics. Samples taken from exposure, were studied for density, hysteresis of thermomagnetic properties, orientation of the residual magnetization.

COMPARISON OF CARDIAC MAGNETIC FIELD DISTRIBUTIONS DURING DEPOLARIZATION AND REPOLARIZATION

2003 ◽  
Vol 13 (12) ◽  
pp. 3783-3789 ◽  
Author(s):  
F. E. SMITH ◽  
P. LANGLEY ◽  
L. TRAHMS ◽  
U. STEINHOFF ◽  
J. P. BOURKE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Field Distribution ◽  
Normal Subjects ◽  
The Body ◽  
Magnetic Field Distribution ◽  
T Wave ◽  
High Magnetic Field Strength ◽  
The Magnetic Field

Multichannel magnetocardiography measures the magnetic field distribution of the human heart noninvasively from many sites over the body surface. Multichannel magnetocardiogram (MCG) analysis enables regional temporal differences in the distribution of cardiac magnetic field strength during depolarization and repolarization to be identified, allowing estimation of the global and local inhomogeneity of the cardiac activation process. The aim of this study was to compare the spatial distribution of cardiac magnetic field strength during ventricular depolarization and repolarization in both normal subjects and patients with cardiac abnormalities, obtaining amplitude measurements by magnetocardiography. MCGs were recorded at 49 sites over the heart from three normal subjects and two patients with inverted T-wave conditions. The magnetic field intensity during depolarization and repolarization was measured automatically for each channel and displayed spatially as contour maps. A Pearson correlation was used to determine the spatial relationship between the variables. For normal subjects, magnetic field strength maps during depolarization (R-wave) showed two asymmetric regions of magnetic field strength with a high positive value in the lower half of the chest and a high negative value above this. The regions of high R-wave amplitude corresponded spatially to concentrated asymmetric regions of high magnetic field strength during repolarization (T-wave). Pearson-r correlation coefficients of 0.7 (p<0.01), 0.8 (p<0.01) and 0.9 (p<0.01) were obtained from this analysis for the three normal subjects. A negative correlation coefficient of -0.7 (p<0.01) was obtained for one of the subjects with inverted T-wave abnormalities, suggesting similar but inverted magnetic field and current distributions to normal subjects. Even with the high correlation values in these four subjects, the MCG was able to identify differences in the distribution of magnetic field strength, with a shift in the T-wave relative to the R-wave. The measurement of cardiac magnetic field distribution during depolarization and repolarization of normal subjects and patients with clinical abnormalities should enable the improvement of theoretical models for the explanation of the cardiac depolarization and repolarization processes.

scholarly journals Field- and Stress-Induced Magnetic Anisotropy in Nanocrystalline Fe-Based and Amorphous Co-Based Alloys

1999 ◽  
Vol 32 (1-4) ◽  
pp. 289-294
Author(s):  
V. A. Lukshina ◽  
N. V. Dmitrieva ◽  
A. P. Potapov
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Magnetic Anisotropy ◽  
Thermomechanical Treatment ◽  
Nanocrystalline Alloy ◽  
Complex Effect ◽  
Induced Magnetic Anisotropy ◽  
The Magnetic Field

For nanocrystalline alloy Fe73.5Cu1Nb3Si13.5B9 thermomechanical treatment was carried out simultaneously with nanocrystallizing annealing (1) or after it (2). It was shown that a change in magnetic properties for the case 1 is essentially greater than for the case 2. Complex effect of thermomagnetic and thermomechanical treatments on magnetic properties was studied in the above-mentioned nanocrystalline alloy as well as in the amorphous alloy Fe5Co70.6Si15B9.4., During the annealings both field and stress were aligned with the long side of the specimens. It was shown that the magnetic field, AC or DC, decreases an effect of loading. Moreover, the magnetic field, AC or DC, applied after stress-annealing can destroy the magnetic anisotropy already induced under load.

scholarly journals Magnetic field disturbances in the sheath region of a super-sonic interplanetary magnetic cloud

2008 ◽  
Vol 26 (10) ◽  
pp. 3153-3158 ◽  
Author(s):  
E. Romashets ◽  
M. Vandas ◽  
S. Poedts
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Storms ◽  
Magnetic Cloud ◽  
The Body ◽  
Magnetic Clouds ◽  
Shock Surface ◽  
Sheath Region ◽  
Magnetic Field Magnitude ◽  
The Magnetic Field ◽  
Magnetic Disturbances

Abstract. It is well-known that interplanetary magnetic clouds can cause strong geomagnetic storms due to the high magnetic field magnitude in their interior, especially if there is a large negative Bz component present. In addition, the magnetic disturbances around such objects can play an important role in their "geo-effectiveness". On the other hand, the magnetic and flow fields in the CME sheath region in front of the body and in the rear of the cloud are important for understanding both the dynamics and the evolution of the interplanetary cloud. The "eventual" aim of this work is to calculate the magnetic field in this CME sheath region in order to evaluate the possible geo-efficiency of the cloud in terms of the maximum |Bz|-component in this region. In this paper we assess the potential of this approach by introducing a model with a simplified geometry. We describe the magnetic field between the CME shock surface and the cloud's boundary by means of a vector potential. We also apply our model and present the magnetic field distribution in the CME sheath region in front of the body and in the rear of the cloud formed after the event of 20 November 2003.

scholarly journals Solar and stellar magnetic flux tubes

1996 ◽  
Vol 176 ◽  
pp. 201-216
Author(s):  
Sami K. Solanki
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Flux ◽  
Large Range ◽  
The Sun ◽  
Flux Tubes ◽  
Magnetic Elements ◽  
Turbulent Pressure ◽  
Magnetic Flux Tubes ◽  
The Magnetic Field

The magnetic field of the Sun is mainly concentrated into intense magnetic flux tubes having field strengths of the order of 1 kG. In this paper an overview is given of the thermal and magnetic properties of these flux tubes, which are known to exhibit a large range in size, from the smallest magnetic elements to sunspots. Differences and similarities between the largest and smallest features are stressed. Some thoughts are also presented on how the properties of magnetic flux tubes are expected to scale from the solar case to that of solar-like stars. For example, it is pointed out that on giants and supergiants turbulent pressure may dominate over gas pressure as the main confining agent of the magnetic field. Arguments are also presented in favour of a highly complex magnetic geometry on very active stars. Thus the very large starspots seen in Doppler images probably are conglomerates of smaller (but possibly still sizable) spots.

Magnetic and magnetoresistive properties of nanocomposites based on Co and SiO

2019 ◽  
Vol 33 (12) ◽  
pp. 1950113 ◽  
Author(s):  
I. M. Pazukha ◽  
Y. O. Shkurdoda ◽  
A. M. Chornous ◽  
L. V. Dekhtyaruk
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Process ◽  
Anisotropic Character ◽  
Co Concentration ◽  
Beam Method ◽  
The Magnetic Field ◽  
Film Nanocomposites

A series of thin-film nanocomposites based on ferromagnetic metal Co and insulator SiO were prepared using an electron-beam method. The magnetoresistive and magnetic properties of these structures deposited at room temperature and then annealed to 700 K were investigated. The results showed that at the Co concentration 40 [Formula: see text]x [Formula: see text] 60 at.%, thin-film nanocomposites exhibit magnetoresistance (MR) that is conditional on spin-dependent tunnelling of electrons. This range of concentrations corresponds to the prepercolation area according to the magnetic investigations. For samples with x [Formula: see text] 70 at.%, the anisotropic character of MR peculiar to the homogeneous ferromagnetic materials appears. According to the magnetic properties study, this range of concentrations corresponds to the area after transition through the percolation threshold. The annealing process in temperature range from 300 K to 700 K in the magnetic field slightly influenced the magnetoresistive properties of the thin-film nanocomposites based on Co and SiO for all range of concentrations.

Relation between wave speeds in the crust of dense magnetic stars

1978 ◽  
Vol 364 (1719) ◽  
pp. 537-552 ◽  
Keyword(s):  
Magnetic Field ◽  
Initial Pressure ◽  
The Body ◽  
Perfect Conductor ◽  
Initial State ◽  
Wave Speeds ◽  
Magnetic Stars ◽  
Arbitrary Strength ◽  
The Magnetic Field ◽  
Relativistic Framework

By studying, within the relativistic framework, the propagation of so-called infinitesimal discontinuities throughout a magnetized elastic perfect conductor in an initial state of high hydrostatic pressure p 0 and in the presence of a magnetic field of arbitrary strength, it is proven that there hold universal relations (i. e., that do not depend on the exact equation of state of the body) between the speeds U f and U s of so-called fast and slow magnetoelastic modes. These results, which should hold true in the crust of dense magnetic stars, have the following form. If A 0 is the relativistic Alfvén number of the initial state and a 0 is the sound speed of a fictitious relativistic perfect fluid whose law of compression would yield the initial pressure p o , then (with nondimensional speeds) U 2 / f = 4/3[ U 2 s (1+ A 2 0 ]+( a 2 0 -4/3 A 2 0 ) for a propagation along the magnetic field and U 2 f (1+ A 2 0 )=4/3 U 2 s +( a 2 0 + A 2 0 ) for a propagation in a direction orthogonal to the magnetic field. These results generalize previous results obtained in relativistic elasticity by Carter and Maugin.

scholarly journals The study of the magnetic properties of matter in strong magnetic fields. Part III.—Magnetostriction

1932 ◽  
Vol 135 (828) ◽  
pp. 537-554 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Fields ◽  
Crystal Lattice ◽  
The Body ◽  
Considerable Part ◽  
Strong Magnetic Fields ◽  
Theoretical Investigations ◽  
General Aspects

Magnetostriction may be defined in general as the change of shape of a substance when it is magnetised. The phenomenon may originate from various causes, but there is one which appears to us to be of major importance. From our present conceptions of the origin of cohesion between the atoms forming a crystal lattice it appears that a considerable part of this cohesion is due to forces of electrodynamical origin; we may therefore expect to influence these forces by means of a magnetic field, and thus produce a change of shape of the body. In ferromagnetic substances magnetostriction is easily observed in ordinary magnetic fields and a number of theoretical investigations have been carried out to explain the general aspects of the phenomenon. With para- and diamagnetic substances, however, no magnetostriction has been observed.

Magnetic Properties of Pbl-xGdxTe

1986 ◽  
Vol 89 ◽  
Author(s):  
M. Gorska ◽  
J. R. Anderson ◽  
Z. Golacki
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Exchange Interaction ◽  
Magnetic Field Dependence ◽  
Antiferromagnetic Exchange ◽  
Brillouin Function ◽  
Parameter Values ◽  
Mn Doped ◽  
The Magnetic Field

AbstractThe magnetization and magnetic susceptibility of Bridgman-grown Pb1-xGdxTe have been measured over a temperature range from 2 to 300 K and in magnetic fields from 0.01 to 50 κOe. The x-values of the crystals ranged from 0.03 to 0.07. The magnetic susceptibility followed a Curie-Weiss behavior, χ = C/(T + θ), with positive θ implying an antiferromagnetic exchange interaction between Gd ions. The magnetic field dependence of the magnetization was fitted to a modified Brillouin function with parameter values that agreed fairly well with those from Curie-Weiss plots. The magnitude of θ was comparable to the value found for Pb1-xMnxTe for similar x values; but since the ion spin is bigger for Gd this suggests that the exchange interaction in Gd-doped PbTe is roughly half the value in Mn-doped PbTe.

Structural and Magnetic Properties of Sintered Materials on the Basis of Zinc Oxide

2013 ◽  
Vol 200 ◽  
pp. 261-266
Author(s):  
Igor Virt ◽  
Igor Rudyi ◽  
Ivan Kurilo ◽  
Ivan Lopatynskyi ◽  
Marian Frugynskyi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnetic Properties ◽  
Theoretical Models ◽  
Structural And Magnetic Properties ◽  
Faraday Method ◽  
The Magnetic Field ◽  
Sintered Materials ◽  
Scanning Electron

Structural and magnetic properties of ceramics Zn1-xCoxO and Zn1-xCrxO are studied. Average sizes of grains are determined by scanning electron microscopy. The magnetic field dependences of magnetic susceptibility are investigated by Faraday method. The relevant theoretical models are chosen.

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