7,936 research outputs found
Southern Chesapeake Bay water color and circulation analysis
There are no author-identified significant results in this report
Torque and temperature dependence of the hysteretic voltage-induced torsional strain in tantalum trisulfide
We have measured the dependence of the hysteretic voltage-induced torsional
strain (VITS) in crystals of orthorhombic tantalum trisulfide on temperature
and applied torque. In particular, applying square-wave voltages above the
charge-density-wave (CDW) threshold voltage, so as to abruptly switch the
strain across its hysteresis loop, we have found that the time constant for the
VITS to switch (at different temperatures and voltages) varied as the CDW
current. Application of torque to the crystal could also change the VITS time
constant, magnitude, and sign, suggesting that the VITS is a consequence of
residual torsional strain in the sample which twist the CDW. Application of
voltage changes the pitch of these CDW twists, which then act back on the
lattice. However, it remains difficult to understand the sluggishness of the
response.Comment: 20 pages, including 7 figures, to be published in PR
Seeding systems for use with a laser velocimeter in large scale wind tunnels
Three seeding systems have been used in the 4- by 7- Meter Tunnel at NASA Langley Research Center: Kerosene smoke, solid particle dry dispersing, and solid particle liquid dispersing. It is anticipated that the liquid dispersing system will be used in all future applications at this facility because: (1) it has a steady output; (2) it is easy to operate and reconfigure; and, (3) it delivers particles of near uniform size
An integrated study of earth resources in the State of California based on Skylab and supporting aircraft data
There are no author-identified significant results in this report
Saturn AS-204/LM-1 postflight trajectory, part 4
Saturn AS-204/LM-1 postflight trajectory analysi
Independent particle descriptions of tunneling from a many-body perspective
Currents across thin insulators are commonly taken as single electrons moving
across classically forbidden regions; this independent particle picture is
well-known to describe most tunneling phenomena. Examining quantum transport
from a different perspective, i.e., by explicit treatment of electron-electron
interactions, we evaluate different single particle approximations with
specific application to tunneling in metal-molecule-metal junctions. We find
maximizing the overlap of a Slater determinant composed of single particle
states to the many-body current-carrying state is more important than energy
minimization for defining single particle approximations in a system with open
boundary conditions. Thus the most suitable single particle effective potential
is not one commonly in use by electronic structure methods, such as the
Hartree-Fock or Kohn-Sham approximations.Comment: 4+ pages, 4 figures; accepted to Phys. Rev. B Rapid Communication
Magnetosphere-ionosphere coupling currents in Jupiter's middle magnetosphere: effect of magnetosphere-ionosphere decoupling by field-aligned auroral voltages
We consider the effect of field-aligned voltages on the magnetosphere-ionosphere coupling current system associated with the breakdown of rigid corotation of equatorial plasma in Jupiter's middle magnetosphere. Previous analyses have assumed perfect mapping of the electric field and flow along equipotential field lines between the equatorial plane and the ionosphere, whereas it has been shown that substantial field-aligned voltages must exist to drive the field-aligned currents associated with the main auroral oval. The effect of these field-aligned voltages is to decouple the flow of the equatorial and ionospheric plasma, such that their angular velocities are in general different from each other. In this paper we self-consistently include the field-aligned voltages in computing the plasma flows and currents in the system. A third order differential equation is derived for the ionospheric plasma angular velocity, and a power series solution obtained which reduces to previous solutions in the limit that the field-aligned voltage is small. Results are obtained to second order in the power series, and are compared to the original zeroth order results with no parallel voltage. We find that for system parameters appropriate to Jupiter the effect of the field-aligned voltages on the solutions is small, thus validating the results of previously-published analyses
Weak Hopf algebras corresponding to Cartan matrices
We replace the group of group-like elements of the quantized enveloping
algebra of a finite dimensional semisimple Lie algebra
by some regular monoid and get the weak Hopf algebra
. It is a new subclass of weak Hopf algebras
but not Hopf algebras. Then we devote to constructing a basis of
and determine the group of weak Hopf algebra
automorphisms of when is not a root of
unity.Comment: 21 page
- …