22,485 research outputs found
The plasma radiation shield - Concept, and applications to space vehicles
Plasma radiation shield - concept and applications to space vehicle
Possible acceleration of charged particles through the reconnection of magnetic field lines in interplanetary space
Prominent intensity spikes in the flux of protons and alphas with less than 0.5 MeV per charge were observed in the region several hours behind an interplanetary shock front. The small spatial scale of these events and the high anisotropy of the particle flux suggest local acceleration. The spectra of the particles, which are cut off at equal energy per charge, suggest acceleration through an electric field. The possibility is examined that these events have their origin in active magnetic neutral sheets in the shocked solar wind
Noise and thermal stability of vibrating micro-gyrometers preamplifiers
The preamplifier is a critical component of gyrometer's electronics. Indeed
the resolution of the sensor is limited by its signal to noise ratio, and the
gyrometer's thermal stability is limited by its gain drift. In this paper, five
different kinds of preamplifiers are presented and compared. Finally, the
design of an integrated preamplifier is shown in order to increase the gain
stability while reducing its noise and size.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/EDA-Publishing
Fe-doping-induced evolution of charge-orbital ordering in a bicritical-state manganite
Impurity effects on the stability of a ferromagnetic metallic state in a
bicritical-state manganite, (La0.7Pr0.3)0.65Ca0.35MnO3, on the verge of
metal-insulator transition have been investigated by substituting a variety of
transition-metal atoms for Mn ones. Among them, Fe doping exhibits the
exceptional ability to dramatically decrease the ferromagnetic transition
temperature. Systematic studies on the magnetotransport properties and x-ray
diffraction for the Fe-doped crystals have revealed that charge-orbital
ordering evolves down to low temperatures, which strongly suppresses the
ferromagnetic metallic state. The observed glassy magnetic and transport
properties as well as diffuse phase transition can be attributed to the
phase-separated state where short-range charge-orbital-ordered clusters are
embedded in the ferromagnetic metallic matrix. Such a behavior in the Fe-doped
manganites form a marked contrast to the Cr-doping effects on
charge-orbital-ordered manganites known as impurity-induced collapse of
charge-orbital ordering.Comment: 8 pages, 7 figure
Analysis of the feasibility of an experiment to measure carbon monoxide in the atmosphere
The feasibility of measuring atmospheric carbon monoxide from a remote platform using the correlation interferometry technique was considered. It has been determined that CO data can be obtained with an accuracy of 10 percent using this technique on the first overtone band of CO at 2.3 mu. That band has been found to be much more suitable than the stronger fundamental band at 4.6 mu. Calculations for both wavelengths are presented which illustrate the effects of atmospheric temperature profiles, inversion layers, ground temperature and emissivity, CO profile, reflectivity, and atmospheric pressure. The applicable radiative transfer theory on which these calculations are based is described together with the principles of the technique
An experimental and computational investigation of the flow field about a transonic airfoil in supercritical flow with turbulent boundary-layer separation
A combined experimental and computational research program is described for testing and guiding turbulence modeling within regions of separation induced by shock waves incident in turbulent boundary layers. Specifically, studies are made of the separated flow the rear portion of an 18%-thick circular-arc airfoil at zero angle of attack in high Reynolds number supercritical flow. The measurements include distributions of surface static pressure and local skin friction. The instruments employed include highfrequency response pressure cells and a large array of surface hot-wire skin-friction gages. Computations at the experimental flow conditions are made using time-dependent solutions of ensemble-averaged Navier-Stokes equations, plus additional equations for the turbulence modeling
A note on the calculation of the effective range
The closed form of the first order non-linear differential equation that is
satisfied by the effective range within the variable phase formulation of
scattering theory is discussed. It is shown that the conventional method of
determining the effective range, by fitting a numerical solution of the
Schr\"odinger equation to known asymptotic boundary conditions, can be modified
to include the first order contribution of a long range interaction.Comment: 4 page
Weber-like interactions and energy conservation
Velocity dependent forces varying as (such as Weber force), here called Weber-like forces, are examined
from the point of view of energy conservation and it is proved that they are
conservative if and only if . As a consequence, it is shown that
gravitational theories employing Weber-like forces cannot be conservative and
also yield both the precession of the perihelion of Mercury as well as the
gravitational deflection of light.Comment: latex, 11 pages, no figure
Kondo effect and spin-active scattering in ferromagnet-superconductor junctions
We study the interplay of superconducting and ferromagnetic correlations on
charge transport in different geometries with a focus on both a quantum point
contact as well as a quantum dot in the even and the odd state with and without
spin-active scattering at the interface. In order to obtain a complete picture
of the charge transport we calculate the full counting statistics in all cases
and compare the results with experimental data. We show that spin-active
scattering is an essential ingredient in the description of quantum point
contacts. This holds also for quantum dots in an even charge state whereas it
is strongly suppressed in a typical Kondo situation. We explain this feature by
the strong asymmetry of the hybridisations with the quantum dot and show how
Kondo peak splitting in a magnetic field can be used for spin filtering. For
the quantum dot in the even state spin-active scattering allows for an
explanation of the experimentally observed mini-gap feature.Comment: 14 pages, 7 figures, accepted by PR
MONEOS 2014 - 13 uursmetingen: factual data rapport: stromingen, debiet en sediment concentratie
- …