Obtaining anisotropic hexagonal ferrites for substrates microstrip microwave devices of mm-range of radiation thermal sintering

2016 ◽  
Author(s):  
Пашков ◽  
A. Pashkov ◽  
Костишин ◽  
V. Kostishin ◽  
Исаев ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Manufacturing Process ◽  
Short Wave ◽  
Hexagonal Ferrite ◽  
Hexagonal Ferrites ◽  
Millimeter Wavelength ◽  
Ferrite Substrate ◽  
Wavelength Radiation ◽  
Thermal Sintering ◽  
High Degree

We obtain polycrystalline hexagonal ferrite substrate of subminiature devices microstrip ferrite decoupling short-wave part of the centimeter and millimeter wavelength radiation and thermal sintering. A feature of the manufacture of anisotropic hexagonal ferrite technology radiation-thermal sintering is pressing in a strong magnetic field applied in the direction of compression, which allows target particles and to obtain a material with a high degree of texture, and the use of various compounds and dopants in the manufacturing process, allows you to control electromagnetic and magnetic hexagonal ferrites.

Fabrication and characterization of highly textured (Bi,Pb)2Sr2Ca2Cu3Ox superconducting ceramics using high magnetic field and cold isostatic pressing

1995 ◽  
Vol 10 (10) ◽  
pp. 2433-2443 ◽  
Author(s):  
Wai Lo ◽  
R. Stevens ◽  
R. Doyle ◽  
A.M. Campbell ◽  
W.Y. Liang
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Cold Isostatic Pressing ◽  
Sintered Ceramic ◽  
Grain Alignment ◽  
Isostatic Pressing ◽  
Transmission Electron ◽  
Superconducting Ceramics ◽  
High Degree

High textured (Bi,Pb)2Sr2Ca2Cu3Ox ceramics have been fabricated by aligning deflocculated flakes of (Bi,Pb)2Sr2Ca2Cu3Ox suspended in an organic medium by means of a high de magnetic field (6 T) at room temperature followed by cold isostatic pressing. The proportion of the (Bi,Pb)2Sr2Ca2Cu3Ox phase in the precursor powder was carefully controlled, and the characteristics of the powder, such as size distribution and morphology, were determined. A high degree of grain alignment was found in the specimens after the magnetic alignment, although the bulk density of the materials was low. Cold isostatic pressing substantially increased the density of the magnetically prealigned specimens which also resulted in a slight decrease in the degree of grain alignment. This minor realignment was found to be due to the various kinds of processing defects that appeared in the specimens during compaction due to the grinding and cracking of the grains and their interlocking. The microstructural and superconducting properties of the sintered ceramic have been studied using texture goniometry, high resolution scanning electron microscopy, transmission electron microscopy, ac magnetic susceptometry, and critical current measurements.

Investigation of the influence of the mode of heat treatment of the initial powder on the efficiency of sintering zirconium ceramics by dilatometry

2021 ◽  
Vol 103 (3) ◽  
pp. 17-24
Author(s):  
S. Shevelev ◽  
◽  
E. Sheveleva ◽  
O. Stary ◽  
Keyword(s):  
Thermal Annealing ◽  
Zirconium Dioxide ◽  
Annealing Temperature ◽  
Average Particle Size ◽  
Average Particle ◽  
Sintered Ceramic ◽  
Tetragonal Modification ◽  
Thermal Sintering ◽  
Powder Compacts ◽  
High Degree

Using methods of synchronous thermal and X-ray structural analyzes applied to zirconium dioxide powders partially stabilized with yttrium obtained by chemical coprecipitation the processes of dehydration of these powders during annealing in air have been investigated. Using the dilatometry method, the regularities of compaction of powder compacts have been investigated with thermal sintering. It was found that the resulting powders mainly consist of the tetragonal modification zirconium dioxide and are nano-sized. The average particle size was 25 nm. The resulting powders are characterized by a high degree of agglomeration. It is shown that an increase in the thermal annealing temperature from 500 to 700ºС leads to partial baking of individual particles inside the agglomerate, and causes the formation of hard agglomerates, the presence of which complicates the processes of compaction and subsequent sintering. The presence of such agglomerates prevents the production of ceramics with high mechanical characteristics: density and porosity. Thermal annealing temperature increase leads to a decrease in the density of the sintered ceramic and a decrease in its hardness.

scholarly journals The orientation of iron–sulphur clusters in membrane multilayers prepared from aerobically-grown Escherichia coli K12 and a cytochrome-deficient mutant

1980 ◽  
Vol 190 (2) ◽  
pp. 385-393 ◽  
Author(s):  
Haywood Blum ◽  
Robert K. Poole ◽  
Tomoko Ohnishi
Keyword(s):  
Magnetic Field ◽  
Escherichia Coli ◽  
Cytoplasmic Membrane ◽  
Deficient Mutant ◽  
E Coli ◽  
Membrane Particles ◽  
Degree Of Orientation ◽  
High Degree ◽  
Cytochrome Content ◽  
The Magnetic Field

1. Membrane particles prepared from ultrasonically-disrupted, aerobically-grown Escherichia coli were centrifuged on to a plastic film that was supported perpendicular to the centrifugal field to yield oriented membrane multilayers. In such preparations, there is a high degree of orientation of the planes of the membranes such that they lie parallel to each other and to the supporting film. 2. When dithionite- or succinate-reduced multilayers are rotated in the magnetic field of an e.p.r. spectrometer, about an axis lying in the membrane plane, angular-dependent signals from an iron–sulphur cluster at gx=1.92, gy=1.93 and gz=2.02 are seen. The g=1.93 signal has maximal amplitude when the plane of the multilayer is perpendicular to the magnetic field. Conversely, the g=2.02 signal is maximal when the plane of the multilayer is parallel with the magnetic field. 3. Computer simulations of the experimental data show that the cluster lies in the cytoplasmic membrane with the gy axis perpendicular to the membrane plane and with the gx and gz axes lying in the membrane plane. 4. In partially-oxidized multilayers, a signal resembling the mitochondrial high-potential iron–sulphur protein (Hipip) is seen whose gz=2.02 axis may be deduced as lying perpendicular to the membrane plane. 5. Appropriate choice of sample temperature and receiver gain reveals two further signals in partially-reduced multilayers: a g=2.09 signal arises from a cluster with its gz axis in the membrane plane, whereas a g=2.04 signal is from a cluster with the gz axis lying along the membrane normal. 6. Membrane particles from a glucose-grown, haem-deficient mutant contain dramatically-lowered levels of cytochromes and exhibit, in addition to the iron–sulphur clusters seen in the parental strain, a major signal at g=1.90. 7. Only the latter may be demonstrated to be oriented in multilayer preparations from the mutant. 8. Comparisons are drawn between the orientations of the iron–sulphur proteins in the cytoplasmic membrane of E. coli and those in mitochondrial membranes. The effects of diminished cytochrome content on the properties of the iron–sulphur proteins are discussed.

Quantum Approximation for Josephson's Tunneling in Thx DUO2 Nano Material for 535 Tesla at Muon Cyclotron

2013 ◽  
Vol 789 ◽  
pp. 157-160
Author(s):  
Moh. Hardiyanto
Keyword(s):  
Magnetic Field ◽  
Hadron Collider ◽  
Mathematical Formulation ◽  
Nuclear Research ◽  
Josephson Tunneling ◽  
Nuclear Research Reactor ◽  
Covariant Equation ◽  
High Degree ◽  
Quantum Condition ◽  
Experimental Effort

The convergence quantum states of free covariant equation in Einsteins space with quantum condition is studied using the ABR (Abrikosov-Balseiro-Russell) formulation in convergence approximation for Josephson tunneling is important role for determine of neutrino particle existing, especially after Cerenkovs effect for 517 tesla super magnetic at Large Hadron Collider (LHC) Cyclotron in CERN, Lyon, France based on ThxDUO2nanomaterial. This approaching will be solved the problem for determine the value of interstellar Electrical Conductivity (EC) on DUO2chain reaction, then the post condition of muon has been known exactly. In this research shown the value of EC is 4.32 μeV at 378 tesla magnetic field for 2.1 x 104ci/mm fast thermal neutron floating in 45.7 megawatts adjusted power of CERNs Cyclotron. The resulted by special Electron-Scanning-Nuclear-Absorbtion (ESNA) shown any possibilities of Josephsons tunneling must be boundary by muon particles without neutrino particle existing for 350 456 tesla magnetic field on UO2more enrichment nuclear fuel at CERN, whereas this research has purpose for provide the mathematical formulation to boundary of muons moving at nuclear research reactor to a high degree of accuracy and with Catch-Nuc, one of nuclear beam equipment has a few important value of experimental effort.

scholarly journals MHD aspect of current sheet oscillations related to magnetic field gradients

2009 ◽  
Vol 27 (1) ◽  
pp. 417-425 ◽  
Author(s):  
N. V. Erkaev ◽  
V. S. Semenov ◽  
I. V. Kubyshkin ◽  
M. V. Kubyshkina ◽  
H. K. Biernat
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
Field Component ◽  
Short Wave ◽  
Magnetic Field Component ◽  
Wave Number ◽  
Dispersion Function ◽  
Small Scale ◽  
Magnetic Field Gradients ◽  
Normal Magnetic Field

Abstract. One-fluid ideal MHD model is applied for description of current sheet flapping disturbances appearing due to a gradient of the normal magnetic field component. The wave modes are studied which are associated to the flapping waves observed in the Earth's magnetotail current sheet. In a linear approximation, solutions are obtained for model profiles of the electric current and plasma densities across the current sheet, which are described by hyperbolic functions. The flapping eigenfrequency is found as a function of wave number. For the Earth's magnetotail conditions, the estimated wave group speed is of the order of a few tens kilometers per second. The current sheet can be stable or unstable in dependence on the direction of the gradient of the normal magnetic field component. The obtained dispersion function is used for calculation of the flapping wave disturbances, which are produced by the given initial Gaussian perturbation at the center of the current sheet and propagating towards the flanks. The propagating flapping pulse has a smooth leading front, and a small scale oscillating trailing front, because the short wave oscillations propagate much slower than the long wave ones.

scholarly journals Giant Spin Current Rectification Due to the Interplay of Negative Differential Conductance and a Non-Uniform Magnetic Field

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1311
Author(s):  
Kang Hao Lee ◽  
Vinitha Balachandran ◽  
Ryan Tan ◽  
Chu Guo ◽  
Dario Poletti
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Spin Current ◽  
System Size ◽  
Differential Conductance ◽  
Many Body ◽  
Negative Differential Conductance ◽  
Ferromagnetic Domains ◽  
Current Rectification ◽  
High Degree

In XXZ chains with large enough interactions, spin transport can be significantly suppressed when the bias of the dissipative driving becomes large enough. This phenomenon of negative differential conductance is caused by the formation of two oppositely polarized ferromagnetic domains at the edges of the chain. Here, we show that this many-body effect, combined with a non-uniform magnetic field, can allow for a high degree of control of the spin current. In particular, by studying all of the possible shapes of local magnetic fields potentials, we find that a configuration in which the magnetic field points up for half of the chain and down for the other half, can result in giant spin-current rectification, for example, up to 108 for a system with only 8 spins. Our results show clear indications that the rectification can increase with the system size.

Emission of microwave and millimeter wavelength radiation during hollow cathode discharge operation of the back lighted thyratron

1992 ◽  
Vol 61 (23) ◽  
pp. 2779-2781 ◽  
Author(s):  
R. Liou ◽  
H. Figueroa ◽  
A. H. McCurdy ◽  
G. Kirkman‐Amemiya ◽  
R. J. Temkin ◽  
...  
Keyword(s):  
Hollow Cathode ◽  
Hollow Cathode Discharge ◽  
Millimeter Wavelength ◽  
Discharge Operation ◽  
Wavelength Radiation

Modelling the core magnetic field of the Earth

1982 ◽  
Vol 306 (1492) ◽  
pp. 179-191 ◽  
Keyword(s):  
Magnetic Field ◽  
Spherical Harmonics ◽  
Secular Variation ◽  
Long Wavelength ◽  
Core Field ◽  
The Core ◽  
The Earth ◽  
High Degree ◽  
Current Systems ◽  
The Magnetic Field

The magnetic field generated in the core of the Earth is often represented by spherical harmonics of the magnetic potential. It has been found from looking at the equations of spherical harmonics, and from studying the values of the spherical harmonic coefficients derived from data from Magsat, that this is an unsatisfactory way of representing the core field. Harmonics of high degree are characterized by generally shorter wavelength expressions on the surface of the Earth, but also contain very long wavelength features as well. Thus if it is thought that the higher degree harmonics are produced by magnetizations within the crust of the Earth, these magnetizations have to be capable of producing very long wavelength signals. Since it is impossible to produce very long wavelength signals of sufficient amplitude by using crustal magnetizations of reasonable intensity, the separation of core and crustal sources by using spherical harmonics is not ideal. We suggest that a better way is to use radial off-centre dipoles located within the core of the Earth. These have several advantages. Firstly, they can be thought of as modelling real physical current systems within the core of the Earth. Secondly, it can be shown that off-centred dipoles, if located deep within the core, are more effective at removing long wavelength signals of potential or field than can be achieved by using spherical harmonics. The disadvantage is that it is much more difficult to compute the positions and strengths of the off-centred dipole fields, and much less easy to manipulate their effects (such as upward and downward continuation). But we believe, along with Cox and Alldredge & Hurwitz, that the understanding that we might obtain of the Earth’s magnetic field by using physically reasonable models rather than mathematically convenient models is very important. We discuss some of the radial dipole models that have been proposed for the nondipole portion of the Earth’s field to arrive at a model that agrees with observations of secular variation and excursions.

Rayleigh-Taylor Instability of a Stratified Plasma

1974 ◽  
Vol 29 (3) ◽  
pp. 518-523 ◽  
Author(s):  
K. M. Srivastava
Keyword(s):  
Magnetic Field ◽  
Boussinesq Approximation ◽  
Short Wave ◽  
Taylor Instability ◽  
Larmor Radius ◽  
Finite Larmor Radius ◽  
Wave Disturbances ◽  
Magnetic Field Gradients ◽  
Rayleigh Taylor Instability ◽  
The Magnetic Field

We have investigated the effect of finite Larmor radius on the Rayleigh-Taylor instability of a semi-infinite, compressible, stratified and infinitely conducting plasma. The plasma is assumed to have a one dimensional density and magnetic field gradients. The eigenvalue problem has been solved under Boussinesq approximation for disturbances parallel to the magnetic field. It has been established that for perturbation parallel to the magnetic field, the system is stable for both stable and unstable stratification. For perturbation perpendicular to the magnetic field, the problem has been solved without Boussinesq approximation. The dispersion relation has been discussed in the two limiting cases, the short and long wave disturbances. It has been observed that the gyroviscosity has a destabilizing influence from k = 0 to k = 4.5 for ß* = 0.1 and for ß* = 0.1 up to k* = 2.85 and then onwards it acts as a stabilizing agent. It has a damping effect on the short wave disturbances. For some parameters, the largets imaginary part has been shown in Figs. 1 and 2

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