93,665 research outputs found
Ablation structures Patent
Design, development, and characteristics of ablation structure
Vehicle parachute and equipment jettison system Patent
Parachute system for lowering manned spacecraft from post-reentry to ocean landin
Aerial capsule emergency separation device Patent
Aerial capsule emergency separation device using jettisonable tower
Nondestructive testing of brazed rocket engine components
Report details study made of nondestructive radiographic, ultrasonic, thermographic, and leak test methods used to inspect and evaluate the quality of the various brazed joints in liquid-propellant rocket engine components and assemblies. Descriptions of some of the unique equipment and methods developed are included
Modification and improvements to cooled blades Patent
Modification and improvement of turbine blades for maximum cooling efficienc
Spontaneous Spin Polarization in Quantum Wires
A number of recent experiments report spin polarization in quantum wires in
the absence of magnetic fields. These observations are in apparent
contradiction with the Lieb-Mattis theorem, which forbids spontaneous spin
polarization in one dimension. We show that sufficiently strong interactions
between electrons induce deviations from the strictly one-dimensional geometry
and indeed give rise to a ferromagnetic ground state in a certain range of
electron densities.Comment: 4 pages, 4 figure
From Point Defects in Graphene to Two-Dimensional Amorphous Carbon
While crystalline two-dimensional materials have become an experimental
reality during the past few years, an amorphous 2-D material has not been
reported before. Here, using electron irradiation we create an sp2-hybridized
one-atom-thick flat carbon membrane with a random arrangement of polygons,
including four-membered carbon rings. We show how the transformation occurs
step-by-step by nucleation and growth of low-energy multi-vacancy structures
constructed of rotated hexagons and other polygons. Our observations, along
with first-principles calculations, provide new insights to the bonding
behavior of carbon and dynamics of defects in graphene. The created domains
possess a band gap, which may open new possibilities for engineering
graphene-based electronic devices.Comment: 10 pages, 10 figures including supplementary informatio
Linear response in infinite nuclear matter as a tool to reveal finite size instabilities
Nuclear effective interactions are often modelled by simple analytical
expressions such as the Skyrme zero-range force. This effective interaction
depends on a limited number of parameters that are usually fitted using
experimental data obtained from doubly magic nuclei. It was recently shown that
many Skyrme functionals lead to the appearance of instabilities, in particular
when symmetries are broken, for example unphysical polarization of odd-even or
rotating nuclei. In this article, we show how the formalism of the linear
response in infinite nuclear matter can be used to predict and avoid the
regions of parameters that are responsible for these unphysical instabilities.Comment: Based on talk presented at 18th Nuclear Physics Workshop "Maria and
Pierre Curie", 2011, Kazimierz, Polan
Integrability of the critical point of the Kagom\'e three-state Potts mode
The vicinity of the critical point of the three-state Potts model on a
Kagom\'e lattice is studied by mean of Random Matrix Theory. Strong evidence
that the critical point is integrable is given.Comment: 1 LaTex file + 3 eps files 7 page
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