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Magnetic Response (magnetic + response)

Distribution by Scientific Domains

Polymers and Materials Science	33%
Psychology	25%
Earth and Environmental Science	16%

Selected Abstracts

Basement controls on Acadian thrusting and fault reactivation along the southern margin of the Welsh Basin

GEOLOGICAL JOURNAL, Issue 5 2009
D. I. Schofield
Abstract Inversion of the Lower Palaeozoic Welsh Basin during the Early to Mid-Devonian is generally thought to have been achieved by a combination of approximately co-axial shortening and transcurrent movement along major faults to produce a strongly partitioned transpressional strain. However, new field observations from Rhydwilym in southwest Wales reveal superimposed deformations which indicate that thrust tectonics operated within the Welsh Borderland Fault System (WBFS) along this segment of the basin margin. An increasing regional magnetic response towards the south suggests that contrasting depth to magnetic basement across the WBFS may have buttressed basin shortening and provided the focus for thrusting and late-Caledonian or proto-Variscan reactivation. British Geological Survey © Nerc 2009. All rights reserved. [source]

Tailored Synthesis of Superparamagnetic Gold Nanoshells with Tunable Optical Properties

ADVANCED MATERIALS, Issue 17 2010
Qiao Zhang
Multifunctional Au nanoshells with tunable optical properties and fast magnetic response have been fabricated through a sequence of sol,gel, surface-protected etching, and seed-mediated growth processes. The use of a porous silica layer enhances the uniformity of nanoshell growth, the reproducibility of the synthesis, and the structural and optical stability of the products. [source]

Electric-Field-Tunable Low Loss Multiferroic Ferrimagnetic,Ferroelectric Heterostructures

ADVANCED MATERIALS, Issue 20 2009
Jaydip Das
A novel monolithic multilayered ferrimagnetic, ferroelectric multiferroic heterostructure shows a remarkably large tuning of the magnetic response with an electric field. The heteroepitaxial stack is comprised of a near single crystal yttrium iron garnet (YIG) layer, a ferroelectric barium strontium titanate (BSTO) layer with good electric field tunability, and embedded platinum (Pt) electrodes. [source]

s-polarization Brewster's angle of stratified metal,dielectric metamaterial in optical regime

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2008
Ryosuke Watanabe
Abstract We demonstrate that the optical reflectivity for s-polarized light vanishes at a certain angle in a stratified metal,dielectric metamaterial numerically and experimentally. The metamaterial consists of a unit cell where a Ag layer of 30 nm thickness is sandwiched by Al2O3 layers of 60 nm thickness. In order to understand the phenomenon in terms of effective permittivity and permeability, we extended a field-sampling method. The permeability is found to be significantly different from unity, which is the origin of Brewster's angle for s-polarization. The microscopic field distribution is readily coarse grained with the effective optical parameters. The present result is a manifestation of the magnetic response in the optical regime. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Facile synthesis of C8 -functionalized magnetic silica microspheres for enrichment of low-concentration peptides for direct MALDI-TOF MS analysis

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2008
Hemei Chen
Abstract In this study, novel C8 -functionalized magnetic polymer microspheres were prepared by coating single submicron-sized magnetite particle with silica and subsequent modification with chloro (dimethyl) octylsilane. The resulting C8 -functionalized magnetic silica (C8 -f-M-S) microspheres exhibit well-defined magnetite-core-silica-shell structure and possess high content of magnetite, which endow them with high dispersibility and strong magnetic response. With their magnetic property, the synthesized C8 -f-M-S microspheres provide a convenient and efficient way for enrichment of low-abundance peptides from tryptic protein digest and human serum. The enriched peptides/proteins were subjected for MALDI-TOF MS analysis and the enrichment efficiency was documented. In a word, the facile synthesis and efficient enrichment process of the novel C8 -f-M-S microspheres make them promising candidates for isolation of peptides even in complex biological samples such as serum, plasma, and urine. [source]

Electrical and magnetic response of archaeological features at the early neolithic site of Movila lui Deciov, western Romania

ARCHAEOLOGICAL PROSPECTION, Issue 4 2004
J. M. Maillol
Abstract An archaeological geophysics survey was conducted on the early neolithic site of Movila lui Deciov, in the Province of Banat, Romania. Magnetometry and electromagnetic terrain conductivity were used for the main prospection effort, and a test of electrical resistivity imaging was conducted on a selected profile. In addition, magnetic susceptibility measurements were obtained from excavation pit samples. The magnetic survey was successful in determining the extent of the site, in delimiting zones rich in structures and artefacts, and in confirming the presence of a ditched enclosure that could be the earliest known in the region. The electromagnetic survey was limited by a lack of resolution of electrical property contrast. Detailed joint modelling of the magnetic and electrical response of the subsurface was used to confirm that electrical resistivity imaging can provide depth information to complement magnetic mapping. One of very few reported in Romania, this survey paves the way for an increased use of geophysical techniques in the cultural heritage management of this country. From a methodological viewpoint, this work further demonstrates the potential of electrical resistivity imaging in archaeology Copyright © 2004 John Wiley & Sons, Ltd. [source]

Magnetic-Field Effects in Organic Semiconducting Materials and Devices

ADVANCED MATERIALS, Issue 14-15 2009
Bin Hu
Abstract It has been experimentally discovered that a low magnetic field (less than 500 mT) can substantially change the electroluminescence, photoluminescence, photocurrent, and electrical-injection current in nonmagnetic organic semiconducting materials, leading to magnetic-field effects (MFEs). Recently, there has been significant driving force in understanding the fundamental mechanisms of magnetic responses from nonmagnetic organic materials because of two potential impacts. First, MFEs can be powerful experimental tools in revealing and elucidating useful and non-useful excited processes occurring in organic electronic, optical, and optoelectronic devices. Second, MFEs can lead to the development of new multifunctional organic devices with integrated electronic, optical, and magnetic properties for energy conversion, optical communication, and sensing technologies. This progress report discusses magnetically sensitive excited states and charge-transport processes involved in MFEs. The discussions focus on both fundamental theories and tuning mechanisms of MFEs in nonmagnetic organic semiconducting materials. [source]

The effect of word repetition on evoked magnetic responses in the human brain

JAPANESE PSYCHOLOGICAL RESEARCH, Issue 1 2000
Takahiro Sekiguchi
Stimulus repetition improves performance on word recognition tasks. We used magnetoencephalography (MEG) to investigate the brain areas associated with this word repetition effect. The participants were eight men and six women. The stimuli were 162 Japanese words each consisting of four katakana letters. The task was to read the words silently and memorize them for a subsequent recognition test. The words were presented one by one and repeated once after eight intervening words. Recordings were taken from bilateral temporal sites of the brain and the responses to the second presentations of the words were compared with those to the first presentations of the same words. Clear magnetic responses were observed in both the left and right hemispheres. In both hemispheres, the responses to the second words were significantly smaller than those to the first words, 250,600 ms after the stimulus onset. Multidipole source analyses showed that the activities were reduced by repetition in the bilateral peri-Sylvian areas, the bilateral medial temporal lobes, and the left angular gyrus. [source]

Microparticles of poly(methacrylic acid),gadolinium ion complex and their magnetic force microscopic images

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2004
Tsuyoshi Michinobu
Abstract Modified poly(methacrylic acid) microparticles complexed with gadolinium(III) (Gd3+) ions were prepared in 100 nm. The emulsion terpolymerization of methacrylic acid, ethyl acrylate, and allyl methacrylate and the following complexation with Gd3+ ions yielded the polymer particles with different Gd3+ ion contents. Potentiometric titration of the complexation of the particle with Gd3+ ions indicated the formation of a very stable tris-carboxylate coordinate complex with the Gd3+ ion. Electron spin resonance and IR spectra of the complexed particles were dependent on the Gd3+ ion content and the coordination environment in each particle. The microparticles dispersed on a mica substrate were subjected to atomic force microscopy (AFM), followed by magnetic force microscopy (MFM). AFM showed 100-nm-sized and monodispersed spherical images. The following MFM clearly provided strong magnetic responses exactly on the same particle positions, of which the images were also dependent on the Gd3+ ion content in the particle. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1912,1918, 2004 [source]

Cortical processing of near-threshold tactile stimuli: An MEG study

PSYCHOPHYSIOLOGY, Issue 3 2010
Anja Wühle
Abstract In the present study we tested the applicability of a paired-stimulus paradigm for the investigation of near-threshold (NT) stimulus processing in the somatosensory system using magnetoencephalography. Cortical processing of the NT stimuli was studied indirectly by investigating the impact of NT stimuli on the source activity of succeeding suprathreshold test stimuli. We hypothesized that cortical responses evoked by test stimuli are reduced due to the preactivation of the same finger representation by the preceding NT stimulus. We observed attenuation of the magnetic responses in the secondary somatosensory (SII) cortex, with stronger decreases for perceived than for missed NT stimuli. Our data suggest that processing in the primary somatosensory cortex including recovery lasts for <200 ms. Conversely, the occupancy of SII lasts ,500 ms, which points to its role in temporal integration and conscious perception of sensory input. [source]

Magnetic force microscopy of iron oxide nanoparticles and their cellular uptake

BIOTECHNOLOGY PROGRESS, Issue 4 2009
Yu Zhang
Abstract Magnetic force microscopy has the capability to detect magnetic domains from a close distance, which can provide the magnetic force gradient image of the scanned samples and also simultaneously obtain atomic force microscope (AFM) topography image as well as AFM phase image. In this work, we demonstrate the use of magnetic force microscopy together with AFM topography and phase imaging for the characterization of magnetic iron oxide nanoparticles and their cellular uptake behavior with the MCF7 carcinoma breast epithelial cells. This method can provide useful information such as the magnetic responses of nanoparticles, nanoparticle spatial localization, cell morphology, and cell surface domains at the same time for better understanding magnetic nanoparticle-cell interaction. It would help to design magnetic-related new imaging, diagnostic and therapeutic methods. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]