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Magnetic Field Intensity (magnetic + field_intensity)

Distribution by Scientific Domains

Physics and Astronomy	40%

Selected Abstracts

Magnetotransport in AlGaN/GaN and AlGaN/AlN/GaN heterostructures

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2007
G. A. Umana-Membreno
Abstract Two-dimensional electron gas transport in AlN/GaN and AlGaN/GaN heterostructures has been investigated employing geometrical magnetoresistance measurements and quantitative mobility-spectrum analysis. The channel magnetoresistance of ungated four-terminal test structures, with an effective width to length ratio of 10, was measured using pulsed drain-to-source voltages equivalent to longitudinal electric fields up to 750 V/cm at magnetic field intensities up to 12 T and sample temperatures from 10 to 300 K. Two distinct electron populations, with significantly different mobilities, are shown to be present in the channel of both AlGaN/AlN/GaN and AlGaN/GaN heterostructures. It is also shown that application of longitudinal electric fields up to 750 V/cm cause a reduction in the mobility of these carrier populations and change the shape of mobility spectrum of the dominant electron population. The origin of these carrier populations is discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

ELF magnetic fields increase amino acid uptake into Vicia faba L. Roots and Alter Ion movement across the plasma membrane

BIOELECTROMAGNETICS, Issue 5 2002
B.C. Stange
Abstract Vicia faba seedlings, subjected to a 10 µT 50 Hz square wave magnetic field for 40 min together with a radioactive pulse, showed a marked increase in amino acid uptake into intact roots. A more modest increase was observed with a 100 µT 50 Hz square wave. An increase in media conductivity at low field intensities from 10 µT 50 Hz square wave, 100 µT 50 Hz sine wave, and 100 µT 60 Hz square wave fields, indicated an alteration in the movement of ions across the plasma membrane, most likely due to an increase in net outflow of ions from the root cells. Similarly, marked elevation in media pH, indicating increased alkalinity, was observed at 10 and 100µT for both square and sine waves at both 50 and 60 Hz. Our data would indicate that low magnetic field intensities of 10 and 100 µT at 50 or 60 Hz can alter membrane transport processes in root tips. Bioelectromagnetics 23:347,354, 2002. © 2002 Wiley-Liss, Inc. [source]

Biomagnetic fluid flow in a 3D rectangular duct

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2004
E. E. Tzirtzilakis1
Abstract The laminar, incompressible, three-dimensional, fully developed viscous flow of a non-conducting biomagnetic fluid in a impermeable rectangular duct is numerically studied in the presence of an applied magnetic field. It is assumed that the magnetic field strength is sufficiently strong to saturate the biofluid and the magnetization is given as a function of the magnetic field intensity. The system of the partial differential equations, resulting after the introduction of appropriate non-dimensional variables, is solved applying an efficient numerical technique based on a pressure-linked pseudotransient method on a common grid. Results concerning the existence and the uniqueness of the solution, are also given. The obtained results, for different values for the parameters entering into the problem under consideration, show that the flow is appreciably influenced by the presence of the magnetic field. Copyright © 2004 John Wiley & Sons, Ltd. [source]

New local hyperthermia using dextran magnetite complex (DM) for oral cavity: experimental study in normal hamster tongue

ORAL DISEASES, Issue 3 2001
S Wada
The possibility of dextran magnetite complex (DM) as a new hyperthermic material was examined in this study. DM suspension of 56 mg ml ,1 iron concentration was locally injected into the normal tongue of golden hamster. DM injected tongues were heated by 500 kHz alternating current (AC) magnetic field and its serial changes in temperature were recorded at 30-s intervals. The temperature of DM injected tongue was maintained at about 43.0,45.0°C for 30 min by changing the AC magnetic field intensity. While temperature elevations of the contralateral tongue and the rectum were only of minor degree. In experiment on the extent of heating area, there was correlation between volume of black stain area and amount of the injected DM suspension (Y =,18.1 + 1.94X, r= 0.931, P < 0.0001, n= 9). Histological examination after heating revealed brown uniform DM accumulation in the connective tissue between fibers of the tongue muscle. Except for vascular dilatations, no tissue damage was seen in the heated tongue. Thus, DM which has the possibility of selective and uniform heating in local hyperthermia might be useful for oral cancer therapy. [source]

Does equipartition hold in HFPs?

ASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009
D. Dallacasa
Abstract Equipartition of energy between relativistic particles and magnetic field is known to be consistent with observations in most of the large size (hundreds of kpc) radio galaxies. Here we discuss whether such a property holds in the smallest and youngest radio sources, the High Frequency Peakers (HFPs). A few sources have small components with a turnover frequency occurring at a few GHz and therefore a direct measure of the magnetic field intensity can be derived from the spectral peak assuming the spectral turnover is originated by synchrotron self-absorption. The field strengths computed in this way are generally in excellent agreement with the equipartition fields. However, a few exceptions have been found, in sources with an extra deficit of photons in the optically thick part of the spectrum as a consequence of free-free absorption (FFA) (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]