Initial study of strengthening of NiAl–Cr(Mo)–Hf alloys by strong magnetic field

2005 ◽  
Vol 20 (2) ◽  
pp. 295-298 ◽  
Author(s):  
G.J. Ma ◽  
C.W. Wu ◽  
W.L. Zhou ◽  
X.L. Guo ◽  
M.F. Ren ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Bending Strength ◽  
Initial Study ◽  
Magnetic Field Treatment ◽  
The Magnetic Field ◽  
Fracture Section ◽  
Nial Matrix

It was found that after treatment under 10T magnetic field and temperature 900 °C the bending strength of NiAl–Cr(Mo)–Hf alloy is increased by about 75%. The fracture section observation shows that the specimens' ductility is enhanced by the magnetic field treatment. Electron probe microanalysis shows that after treatment of the magnetic field the Heusler phases at NiAl/Cr(Mo) grain boundaries are partially dissolved and the small Heusler phases particles at Cr(Mo) and matrix phases interfaces almost dissolved into NiAl matrix.

scholarly journals Qualitative and quantitative assessment of magnetic vestibular stimulation in humans

2020 ◽  
Vol 30 (6) ◽  
pp. 353-361
Author(s):  
Rebecca S. Dewey ◽  
Rachel Gomez ◽  
Chris Degg ◽  
David M. Baguley ◽  
Paul M. Glover
Keyword(s):  
Magnetic Field ◽  
Objective Measure ◽  
Quantitative Measure ◽  
Vestibular Stimulation ◽  
Initial Study ◽  
Clinical Test ◽  
Healthy Control ◽  
Student’S T ◽  
The Impact ◽  
The Magnetic Field

The sensation of phantom motion or exhibition of bodily sway is often reported in the proximity of an MR scanner. It is proposed that the magnetic field stimulates the vestibular system. There are a number of possible mechanisms responsible, and the relative contributions of susceptibility on the otolithic receptors and the Lorentz force on the cupulae have not yet been explored. This exploratory study aims to investigate the impact of being in the proximity of a 7.0 T MR scanner. The modified clinical test of sensory interaction on balance (mCTSIB) was used to qualitatively ascertain whether or not healthy control subjects who passed the mCTSIB in normal conditions 1) experienced subjective sensations of dizziness, vertigo or of leaning or shifting in gravity when in the magnetic field and 2) exhibited visibly increased bodily sway whilst in the magnetic field compared to outside the magnetic field. Condition IV of the mCTSIB was video recorded outside and inside the magnetic field, providing a semi-quantitative measure of sway. For condition IV of the mCTSIB (visual and proprioceptive cues compromised), all seven locations/orientations around the scanner yielded significantly more sway than at baseline (p < 0.01 FDR). A Student’s t-test comparing the RMS velocity of a motion marker on the upper arm during mCTSIB condition IV showed a significant increase in the amount of motion exhibited in the field (T = 2.59; d.f. = 9; p = 0.029) compared to outside the field. This initial study using qualitative measures of sway demonstrates that there is evidence for MR-naïve individuals exhibiting greater sway while performing the mCTSIB in the magnetic field compared to outside the field. Directional polarity of sway was not significant. Future studies of vestibular stimulation by magnetic fields would benefit from the development of a sensitive, objective measure of balance function, which can be performed inside a magnetic field.

scholarly journals Combined laser and magnetic field treatment of YFeO3—containing films grown by spray-pyrolysis

2004 ◽  
Vol 2 (1) ◽  
pp. 188-195
Author(s):  
N. Mihailov ◽  
O. Vankov ◽  
N. Petrova ◽  
D. Kovacheva
Keyword(s):  
Magnetic Field ◽  
Spray Pyrolysis ◽  
Pulse Duration ◽  
Fused Silica ◽  
Crystallite Sizes ◽  
Citric Complexes ◽  
Magnetic Field Treatment ◽  
Glycol Solution ◽  
The Magnetic Field ◽  
Post Deposition

AbstractThin films (50–1200 nm) of YFeO3 were deposited on fused silica substrates by spray-pyrolysis using ethylene glycol solution of Y-Fe(III) citric complexes. The films were post deposition annealed at 750°C in static air for 2 h. Films obtained in this way were afterwards irradiated by a burst mode operated Nd-YAG laser (pulse energy 650 mJ, pulse duration 700 μs, energy density 110 mJ/cm2). The laser’s onset was synchronized with that of a magnetic field pulse of nearly square shape (magnetic induction 0.5 T, pulse duration 900 μs). The samples were placed normally to the direction of the magnetic field. The treatment does not affect the phase composition of the film but significantly increases the crystallite sizes of the phases presenting in the sample. The saturation magnetization of the films decreases as a result of the laser and magnetic field treatment and the coercive force increases by 50%.

scholarly journals Magnetic dominance of axion electrodynamics: photon capture effect and anisotropy of Coulomb potential

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
S. Villalba-Chávez ◽  
A. E. Shabad ◽  
C. Müller
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Strong Magnetic Field ◽  
Coulomb Potential ◽  
Heat Radiation ◽  
Radiation Mechanism ◽  
Electron Positron ◽  
Coulomb Singularity ◽  
Relativistic Hydrogen ◽  
The Magnetic Field

AbstractFor magnetic fields larger than the characteristic scale linked to axion-electrodynamics, quantum vacuum fluctuations due to axion-like fields can dominate over those associated with the electron-positron fields. This conjecture is explored by investigating both the axion-modified photon capture by a strong magnetic field and the Coulomb potential of a static pointlike charge. We show that in magnetic fields characteristic of neutron stars $$\sim 10^{13}$$ ∼ 10 13 –$$10^{15}\;\mathrm{G}$$ 10 15 G , the capture of gamma photons prior to the production of a pair can prevent the existence of an electron-positron plasma, essential for explaining the pulsar radiation mechanism. This incompatibility is used to limit the axion parameter space. Our bounds improve existing outcomes in the region of mass $$m\sim 10^{-10}$$ m ∼ 10 - 10 –$$10^{-5}\;{\mathrm{eV}}$$ 10 - 5 eV . The effect of capture, known in QED as relating to gamma-quanta, is extended in axion electrodynamics to include X-ray photons with the result that a specially polarized part of the heat radiation from the surface is canalized along the magnetic field. Besides, we find that in the regime in which the dominance takes place, the running QED coupling depends on the field strength and the modified Coulomb potential is of Yukawa-type in the direction perpendicular to the magnetic field at distances much smaller than the axion Compton wavelength, while along the field it follows approximately the Coulomb law at any length scale. Despite the Coulomb singularity manifested in the latter case, we argue that the ground-state energy of a non-relativistic hydrogen atom placed in a strong magnetic field turns out to be bounded due to the nonrenormalizable feature of axion-electrodynamics.

Why only a small fraction of quasars are radio loud?

2018 ◽  
Vol 14 (S342) ◽  
pp. 201-204
Author(s):  
Xinwu Cao
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Angular Momentum ◽  
Angular Velocity ◽  
Strong Magnetic Field ◽  
Weak Magnetic Field ◽  
Thin Disk ◽  
Relativistic Jets ◽  
Jet Formation ◽  
The Magnetic Field

AbstractIt is still a mystery why only a small fraction of quasars contain relativistic jets. A strong magnetic field is a necessary ingredient for jet formation. Gas falls from the Bondi radius RB nearly freely to the circularization radius Rc, and a thin accretion disk is formed within Rc We suggest that the external weak magnetic field threading interstellar medium is substantially enhanced in this region, and the magnetic field at Rc can be sufficiently strong to drive outflows from the disk if the angular velocity of the gas is low at RB. In this case, the magnetic field is efficiently dragged in the disk, because most angular momentum of the disk is removed by the outflows that lead to a significantly high radial velocity. The strong magnetic field formed in this way may accelerate jets in the region near the black hole, either by the Blandford-Payne or/and Blandford-Znajek mechanisms. If the angular velocity of the circumnuclear gas is low, the field advection in the thin disk is inefficient, and it will appear as a radio-quiet (RQ) quasar.

NEUTRINO ENERGY LOSS ON IRON GROUP NUCLEI BY ELECTRON CAPTURE IN STRONG MAGNETIC FIELD AT THE CRUSTS OF NEUTRON STARS

2007 ◽  
Vol 22 (19) ◽  
pp. 3305-3315 ◽  
Author(s):  
JING-JING LIU ◽  
ZHI-QUAN LUO ◽  
HONG-LIN LIU ◽  
XIANG-JUN LAI
Keyword(s):  
Magnetic Field ◽  
Energy Loss ◽  
Neutron Stars ◽  
Strong Magnetic Field ◽  
Electron Capture ◽  
Neutrino Energy ◽  
Iron Group ◽  
Slight Effect ◽  
The Magnetic Field ◽  
Loss Rates

The neutrino energy loss rates on iron group nuclei by electron capture are calculated in a strong magnetic field at the crusts of Neutron stars. The results show that the magnetic field has only a slight effect on the neutrino energy loss rates in a range of 108–1013 G on surfaces of the most neutron stars. Whereas for some magnetars which range of the magnetic field is 1013–1018 G, the neutrino energy loss rates of the most iron group nuclei would be debased greatly and may be even decreased for 4 orders of magnitude by the strong magnetic field.

Textured Beta-Sialon:Eu2+ Phosphor Deposits Fabricated by Electrophoretic Deposition (EPD) Process within a Strong Magnetic Field: Preparation Process and Photoluminescence (PL) Properties Depending on Orientation

2015 ◽  
Vol 654 ◽  
pp. 268-273
Author(s):  
Chen Ning Zhang ◽  
Tetsuo Uchikoshi ◽  
Li Hong Liu ◽  
Benjamin Dierre ◽  
Yu Jin Cho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Electric Field ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Intensity Ratio ◽  
Preparation Process ◽  
Crystal Axis ◽  
Chromaticity Coordinates ◽  
The Magnetic Field

Beta-sialon:Eu2+ phosphor deposits were fabricated by electrophoretic deposition (EPD) process within a strong magnetic field (12 T). The direction of the magnetic field was adjusted to be parallel or perpendicular to that of the electric field, that is, vertical-or horizontal setup. The oriented deposits were fabricated by aligning the β-sialon:Eu2+ particles along the higher magnetic-susceptibility c-crystal axis (a, b-crystal plane). For the case of vertically-setup magnetic field, the oriented deposit aligned along the c-axis possessed higher relative deposit density than the randomly fabricated deposit, as a result, varying the intensity ratio of emission and transmitted excitation, and therefore, presenting different chromaticity coordinates; for the case of horizontally-setup magnetic field, photoluminescence (PL) intensities of the deposits oriented along c-axis were significantly improved by comparing with those of the randomly-oriented ones.

Kinetic and transport theory for a non-neutral plasma taking account of strong gyration and non-uniformities on the collisional scale

1987 ◽  
Vol 38 (3) ◽  
pp. 351-371 ◽  
Author(s):  
Alf H. Øien
Keyword(s):  
Magnetic Field ◽  
Distribution Function ◽  
Electric Field ◽  
Strong Magnetic Field ◽  
Transport Theory ◽  
Collision Integral ◽  
Collision Term ◽  
Third Order ◽  
Derivatives Of ◽  
The Magnetic Field

From the BBGKY equations for a pure electron plasma a derivation is made of a collision integral that includes the combined effects of particle gyration in a strong magnetic field and non-uniformities of both the distribution function and the self-consistent electric field on the collisional scale. A series expansion of the collision integral through the distribution function and the electric field on the collisional scale is carried out to third order in derivatives of the distribution function and to second order in derivatives of the electric field. For the strong-magnetic-field case when collision-term contributions to only first order in 1/B are included, a particle flux transverse to the magnetic field proportional to l/B2 is derived. The importance of long-range collective collisions in this process is shown. The result is in contrast with the classical l/B4 proportionality, and is in accordance with earlier studies.

scholarly journals PHOTON-PAIR CONVERSION INTO NEUTRINOS IN A STRONG MAGNETIC FIELD

2001 ◽  
Vol 16 (25) ◽  
pp. 1659-1665 ◽  
Author(s):  
A. V. KUZNETSOV ◽  
N. V. MIKHEEV
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Strong Magnetic Field ◽  
Asymptotic Form ◽  
Axial Vector ◽  
Electroweak Interaction ◽  
The Other ◽  
The Standard Model ◽  
Loop Amplitude ◽  
The Magnetic Field

A general analysis of the three-vertex loop amplitude in a strong magnetic field, based on the asymptotic form of the electron propagator in the field, is performed. In order to investigate the photon–neutrino process [Formula: see text], the vertex combinations of the scalar–vector–vector (SVV), pseudoscalar–vector–vector (PVV), three-vector (VVV), and axial-vector–vector–vector (AVV) types are considered. It is shown that only the SVV amplitude grows linearly with the magnetic field strength, while in the other amplitudes, PVV, VVV and AVV, the linearly growing terms are canceled. The process [Formula: see text] is investigated in the left–right-symmetric extension of the standard model of electroweak interaction, where the effective scalar νν e e coupling could exist. Possible astrophysical manifestations of the considered process are discussed.

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