scholarly journals SYNTHESIS OF NANOSCALED MAGNETIC MATERIALS ON THE BASIS OF OXIDE SYSTEMS AND MANUFACTURING OF NON-RECIPROCAL COMPOSITE ELEMENTS BASED ON THEM

2019 ◽  
Vol 85 (7) ◽  
pp. 16-23
Author(s):  
Oleksandr Fedorchuk ◽  
Sergii Solopan ◽  
Maksym Popov ◽  
Igor Zavislyak ◽  
Anatolii Belous
Keyword(s):  
Magnetic Field ◽  
Absorption Spectra ◽  
Magnetic Film ◽  
Polymerization Process ◽  
Oxide Systems ◽  
Measuring Cell ◽  
Practical Applications ◽  
Film Forming ◽  
Dynamic Filters ◽  
Magnetic Dielectric

Nanoscaled particles of nickel-zinc ferrites solid solutions were synthesized by the method of precipitation from aqueous solutions, as initial reagents were used nitrates solutions, namely Fe(NO3)3, Ni(NO3)2 and Zn(NO3)3. Cylindrical composite resonant elements in a form of systems “high-Q non-magnetic dielectric – magnetic film” were manufactured using synthesized particles. As a non-magnetic dielectric was used barium tetratitanate BaTi4O9 with a doping of ZnO. For this the film-forming suspension consisted of synthesized ferrite particles and photopolymer was prepared. The suspension was applied on the end face of the dielectric resonator and polymerized by the UV radiation. Magnetic field of electromagnet was applied to the composite resonators during the magnetic film polymerization process (parallel or normal to the resonators axis). Absorption spectra of composite resonators in the waveguide measuring cell under influence of an external magnetic field were obtained. Spectra confirm the opportunity to control the resonance frequency of the composite structure and energy absorption in it using the external permanent magnetic field. The tuning of composite resonators parameters was more efficient for the resonators with the film polymerized in the parallel to the resonator axis field. For the frequency shift and electromagnetic isolation were obtained the values of 71 MHz and 53 dB respectively but with a high “straight” energy losses in the area of ferromagnetic resonance. So, the measuring cell with the composite resonator located in it was simulated using an Ansys HFSS software. Respective absorption spectra were obtained. It is shown that it is possible to manufacture composite resonators with a needed for the practical applications characteristics level (reverse losses were 34 dB, straight losses were 0.8 dB) and a tuning ability for the development of superheterodyne transmitters, dynamic filters for microwave technics, microwave valves, etc.

Change in the absorption spectra of blood exposed to a low-frequency magnetic field

2007 ◽  
Vol 74 (2) ◽  
pp. 223-229 ◽  
Author(s):  
G. A. Zalesskaya ◽  
N. P. Mit’kovskaya ◽  
O. A. Galai ◽  
A. V. Kuchinskii ◽  
O. V. Laskina
Keyword(s):  
Magnetic Field ◽  
Absorption Spectra ◽  
Low Frequency ◽  
Frequency Magnetic Field

scholarly journals Tunable Adhesion of a Bio-Inspired Micropillar Arrayed Surface Actuated by a Magnetic Field

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Xingji Li ◽  
Zhilong Peng ◽  
Yazheng Yang ◽  
Shaohua Chen
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Particles ◽  
Rotation Angle ◽  
Adhesion Force ◽  
Practical Applications ◽  
Section Shape ◽  
Theoretical Predictions ◽  
Large Elastic Deformation ◽  
The Difference

Bio-inspired functional surfaces attract many research interests due to the promising applications. In this paper, tunable adhesion of a bio-inspired micropillar arrayed surface actuated by a magnetic field is investigated theoretically in order to disclose the mechanical mechanism of changeable adhesion and the influencing factors. Each polydimethylsiloxane (PDMS) micropillar reinforced by uniformly distributed magnetic particles is assumed to be a cantilever beam. The beam's large elastic deformation is obtained under an externally magnetic field. Specially, the rotation angle of the pillar's end is predicted, which shows an essential effect on the changeable adhesion of the micropillar arrayed surface. The larger the strength of the applied magnetic field, the larger the rotation angle of the pillar's end will be, yielding a decreasing adhesion force of the micropillar arrayed surface. The difference of adhesion force tuned by the applied magnetic field can be a few orders of magnitude, which leads to controllable adhesion of such a micropillar arrayed surface. Influences of each pillar's cross section shape, size, intervals between neighboring pillars, and the distribution pattern on the adhesion force are further analyzed. The theoretical predictions are qualitatively well consistent with the experimental measurements. The present theoretical results should be helpful not only for the understanding of mechanical mechanism of tunable adhesion of micropillar arrayed surface under a magnetic field but also for further precise and optimal design of such an adhesion-controllable bio-inspired surface in future practical applications.

scholarly journals About the possibility of identification of hydrocarbon deposits with the help of NMR

2016 ◽  
Vol 5 (2) ◽  
pp. 551-559
Author(s):  
Pavlo M. Ivashchenko ◽  
Eduard A. Bakai ◽  
Alexander I. Yurchuk
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Absorption Spectra ◽  
Weak Magnetic Field ◽  
Directional Antennas ◽  
Practical Implementation ◽  
Practical Application ◽  
The Earth ◽  
Hydrocarbon Deposits

Abstract. The main purpose of this article is to review the theoretical prerequisites of nuclear magnetic resonance (NMR) application in tasks of search and exploration of hydrocarbon deposits. The identification peculiarities of hydrocarbon deposits in a weak magnetic field of the Earth were analysed. The necessity of using highly directional antennas for providing greater sounding depths as well as the use of absorption spectra of the sought-for minerals as sounding signals were identified and justified. A variant of practical implementation of such a system was examined and examples of practical application of the innovative NMR technology were provided.

scholarly journals The Magnetoelectric Effect of a Ni0.3Zn0.62Cu0.08Fe2O4 - PbFe0.5Nb0.5O3 Multilayer Composite

2014 ◽  
Vol 59 (3) ◽  
pp. 1011-1015
Author(s):  
P. Guzdek ◽  
M. Sikora ◽  
Ł. Góra ◽  
Cz. Kapusta
Keyword(s):  
Magnetic Field ◽  
Magnetoelectric Effect ◽  
Magnetic Hysteresis ◽  
Tape Casting ◽  
Casting Process ◽  
Layered Composites ◽  
Practical Applications ◽  
Magnetoelectric Composite ◽  
Sinusoidal Magnetic Field ◽  
Magnetoelectric Coefficient

Abstract The magnetoelectric effect in multiferroic materials has been widely studied for its fundamental interest and practical applications. The magnetoelectric effect observed for single phase materials like Cr2O3, BiFeO3, and Pb(Fe0.5Nb0.5)O3 is usually small. A much larger effect can be obtained in composites consisting of magnetostrictive and piezoelectric phases. This paper investigates the magnetoelectric effect of a multilayer (laminated) structure consisting of 6 nickel ferrite and 7 PFN relaxor layers. It describes the synthesis and tape casting process for Ni0.3Zn0.62Cu0.08Fe2O4 ferrite and relaxor PbFe0.5Nb0.5O3 (PFN). Magnetic hysteresis, ZFC - FC curves and dependencies of magnetization versus temperature for PFN relaxor and magnetoelectric composite were measured with a vibrating sample magnetometer (VSM) in an applied magnetic field up to 85 kOe at a temperature range of 10 – 400 K. Magnetoelectric effect at room temperature was investigated as a function of a static magnetic field (0.3 - 6.5 kOe) and the frequency of sinusoidal magnetic field (0.01 - 6.5 kHz). At lower magnetic field, the magnetoelectric coefficient increases slightly before reaching a maximum and then decreases. The magnetoelectric coefficient aME increases continuously as the frequency is raised, although this increase is less pronounced in the 1-6.5 kHz range. Maximum values of the magnetoelectric coefficient attained for the layered composites exceed about 50 mV/(Oe cm).

Low Band-Gap Materials for Solar Cells

2021 ◽  
pp. 176-235
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
Chemical Properties ◽  
Low Energy ◽  
Practical Applications ◽  
Film Forming ◽  
Donor And Acceptor ◽  
Induced Charge

Organic solar cells (OSCs) are discussed at length in terms of its performance leading to the generation of electricity. The key materials required for OSCs are the small organic molecules having donor and acceptor with suitable light absorption and electro-chemical properties of low energy band gap. Various structural scaffolds are highlighted with their structural design leading to film forming in an orderly manner and this morphology of film having a pivotal role in photo-induced charge separation, migration and collection at an electrode. Present day research informs that OSCs involving non fullerene based donors and acceptors are functioning with high photo conversion efficiency [PCE] of >17% and are promising candidates for practical applications.

scholarly journals Physical Structure Induced Hydrophobicity Analyzed from Electrospinning and Coating Polyvinyl Butyral Films

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Shuo Chen ◽  
Guo-Sai Liu ◽  
Hong-Wei He ◽  
Cheng-Feng Zhou ◽  
Xu Yan ◽  
...  
Keyword(s):  
Surface Structure ◽  
Critical Role ◽  
Film Surface ◽  
Polyvinyl Butyral ◽  
Physical Structure ◽  
Surface Wettability ◽  
Practical Applications ◽  
Physical Surface ◽  
Film Forming ◽  
Surface Morphologies

Surface wettability of a film plays a critical role in its practical applications. To control the surface wettability, modification on the physical surface structures has been a useful method. In this paper, we reported the controlling physical surface structure of polyvinyl butyral (PVB) films by different film-forming methods, spin-coating, bar-coating, and electrospinning. The wettability of these PVB films was examined, and the surface morphologies and roughness were investigated. The results indicated that coating PVB films were hydrophilic, while electrospun films were hydrophobic. The physical surface structure was the key role on the interesting transition of their surface wettability. Theoretical analyses on these results found that the coating PVB films showed different mechanism with electrospun ones. These results may help to find the way to control the PVB film surface wettability and then guide for applications.

THE USE OF POISSON’S RELATION FOR THE EXTRACTION OF PSEUDOTOTAL MAGNETIC FIELD INTENSITY FROM GRAVITY OBSERVATIONS

Geophysics ◽  
1971 ◽  
Vol 36 (3) ◽  
pp. 605-608 ◽  
Author(s):  
Edwin S. Robinson
Keyword(s):  
Magnetic Field ◽  
Gravity Field ◽  
Field Data ◽  
Field Potential ◽  
Geological Structure ◽  
Common Source ◽  
Uniform Density ◽  
Practical Applications ◽  
Uniform Magnetization ◽  
Gravity Fields

Investigation of geological structure by gravimetric and magnetic field surveys requires consideration of relationships between gravity anomaly and magnetic anomaly generating sources. The possibility of using Poisson’s Relation to examine magnetic and gravity fields related to a common source is intriguing. This relation is expressed as follows: [Formula: see text] (1) where A (x, y, z) is the magnetic field potential and U (x, y, z) is the gravity field potential at a point in space due to a source of uniform density ρ and uniform magnetization I in the direction α. This expression has been used to derive magnetic anomalies over idealized forms (Nettleton, 1940) and, by Baranov (1957), to extract pseudogravity fields from magnetic field data. The purpose of this paper is to develop an expression for extracting a pseudomagnetic field from gravity field data and to examine the practical applications of this expression.

INFLUENCE OF THE MAGNETIC FIELD ON THE TRANSVERSE RUNAWAY THRESHOLD

2007 ◽  
Vol 21 (10) ◽  
pp. 1715-1720 ◽  
Author(s):  
NANA METREVELI ◽  
ZAUR KACHLISHVILI ◽  
BEKA BOCHORISHVILI
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Fields ◽  
Applied Electric Field ◽  
Nonlinear Oscillations ◽  
Hot Electrons ◽  
Total Field ◽  
Practical Applications ◽  
Energy And Momentum ◽  
The Magnetic Field

The transverse runaway (TR) is a phenomenon whereby for a certain combination of energy and momentum scattering mechanisms of hot electrons, and for a certain threshold of the applied electric field, the internal (total) field tends to infinity. In this work, the effect of the magnetic field on the transverse runaway threshold is considered. It is shown that with increasing magnetic field, the applied critical electric fields relevant to TR decrease. The obtained results are important for practical applications of the TR effect as well as for the investigation of possible nonlinear oscillations that may occur near the TR threshold.

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