3,699 research outputs found
A Deformable Model for Magnetic Vortex Pinning
A two-parameter analytical model of the magnetic vortex in a thin disk of
soft magnetic material is constructed. The model is capable of describing the
change in evolution of net vortex state magnetization and of core position when
the vortex core interacts with a magnetic pinning site. The model employs a
piecewise, physically continuous, magnetization distribution obtained by the
merger of two extensively used one-parameter analytical models of the vortex
state in a disk. Through comparison to numerical simulations of ideal disks
with and without pinning sites, the model is found to accurately predict the
magnetization, vortex position, hysteretic transitions, and 2-D displacement of
the vortex in the presence of pinning sites. The model will be applicable to
the quantitative determination of vortex pinning energies from measurements of
magnetization.Comment: 27 pages, 7 figures, including supplementary information, ancillary
files:3 supplementary movie
Thermo-mechanical sensitivity calibration of nanotorsional magnetometers
We report on the fabrication of sensitive nanotorsional resonators, which can
be utilized as magnetometers for investigating the magnetization dynamics in
small magnetic elements. The thermo-mechanical noise is calibrated with the
resonator displacement in order to determine the ultimate mechanical torque
sensitivity of the magnetometer.Comment: 56th Annual Conference on Magnetism and Magnetic Material
Brief for the United States as Amicus Curiae in Support of Neither Party
Amicus ("friend of the court") brief written by the United States in support of neither party in AMP v. Myriad Genetics (No. 2010-1406)
Dissipative and Dispersive Optomechanics in a Nanocavity Torque Sensor
Dissipative and dispersive optomechanical couplings are experimentally
observed in a photonic crystal split-beam nanocavity optimized for detecting
nanoscale sources of torque. Dissipative coupling of up to approximately
MHz/nm and dispersive coupling of GHz/nm enable measurements of sub-pg
torsional and cantilever-like mechanical resonances with a thermally-limited
torque detection sensitivity of 1.2 in ambient conditions and 1.3 in low vacuum. Interference between
optomechanical coupling mechanisms is observed to enhance detection sensitivity
and generate a mechanical-mode-dependent optomechanical wavelength response.Comment: 11 pages, 6 figure
Original observations of Desmozoon lepeophtherii, a microsporidian hyperparasite infecting the salmon louse Lepeophtheirus salmonis, and its subsequent detection by other researchers
A microsporidian hyperparasite, Desmozoon lepeophtherii, of the parasitic copepod Lepeophtheirus salmonis (salmon louse), infecting farmed Atlantic salmon (Salmo salar), was first discovered in the west of Scotland in 2000. Heavily infected salmon lice are easily recognised as they have large opaque inclusions distributed throughout the body. The prevalence of salmon lice with visible signs of microsporidiosis can be up to 10% of the population from certain farm sites. The microsporidian was also isolated from the host Atlantic salmon suggesting it may have a two host life cycle. The authors believe that the infection in immunocompetent salmon may be latent, becoming acute during periods of infection with another pathogen or during sexual maturation. Since its first discovery in Scotland, Desmozoon lepeophtherii has been subsequently reported from Norway, and more recently from the Pacific coast of North America
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