26,427 research outputs found
Comet Halley returns: A teachers' guide 1985-1986
This booklet has been put together as an aid for teachers in elementary and secondary schools. It is divided into two distinct parts. The first part is a brief tutorial which introduces some of the most important concepts about comets, including their historical significance. A list of selected readings is provided at the end of the booklet. The second part of the booklet contains a number of suggested activities, built around the comet. These include both classroom exercises and carefully described field work to observe the comet. Guidance is provided on where to look for the comet, how to observe it, and to photograph it
Single-stage experimental evaluation of boundary layer bleed techniques for high lift stator blades. Compressors design
Design and evaluation of stator blades for use in boundary layer bleed techniques in axial flow compresso
Single-stage experimental evaluation of boundary layer blowing techniques for high lift stator blades. 1 - Compressor design
Boundary layer blowing techniques for high lift stator blades in axial flow compressor
Population polygons of tektite specific gravity for various localities in australasia
Comparison of specific gravity of tektites from australia, asia, texas, and czechoslovaki
Coherent spin mixing dynamics in a spin-1 atomic condensate
We study the coherent off-equilibrium spin mixing inside an atomic
condensate. Using mean field theory and adopting the single spatial mode
approximation (SMA), the condensate spin dynamics is found to be well described
by that of a nonrigid pendulum, and displays a variety of periodic oscillations
in an external magnetic field. Our results illuminate several recent
experimental observations and provide critical insights into the observation of
coherent interaction-driven oscillations in a spin-1 condensate.Comment: 6 pages, 5 eps figures, update the discussion of the experimental
result
Localization of spin mixing dynamics in a spin-1 Bose-Einstein condensate
We propose to localize spin mixing dynamics in a spin-1 Bose-Einstein
condensate by a temporal modulation of spin exchange interaction, which is
tunable with optical Feshbach resonance. Adopting techniques from coherent
control, we demonstrate the localization/freezing of spin mixing dynamics, and
the suppression of the intrinsic dynamic instability and spontaneous spin
domain formation in a ferromagnetically interacting condensate of Rb
atoms. This work points to a promising scheme for investigating the weak
magnetic spin dipole interaction, which is usually masked by the more dominant
spin exchange interaction.Comment: 4 pages, 5 eps figures, published in Phys. Rev. A
The motion of superconducting vortices in thin films of varying thickness
The interaction of superconducting vortices with superconductor/vacuum interfaces is considered. A vortex is first shown to intersect such an interface normally. Various thin-film models are then formulated, corresponding to different parameter regimes. A local analysis of a vortex is performed, and a law of motion for each vortex deduced. This law of motion implies that the vortex will move to the locally thinnest part of the film, and is consistent with the vortex moving under the curvature induced by being forced to intersect the boundaries of the film normall
- …