3,052 research outputs found
On the Supergravity Evaluation of Wilson Loop Correlators in Confining Theories
We explicitly show the area law behavior of a circular Wilson loop in
confining theories from supergravity. We calculate the correlator of two Wilson
loops from supergravity in confining backgrounds. We find that it is dominated
by an exchange of a ``scalarball'' that is lighter than the glueballs. We
interpret these results in terms of the meson-meson potential in such theories.Comment: Latex, 13 pages, 2 figure
On the extreme points of quantum channels
Let L(m,n) denote the convex set of completely positive trace preserving
operators from C^{m x m} to C^{n x n}$, i.e quantum channels. We give a
necessary condition for L in L(m,n) to be an extreme point. We show that
generically, this condition is also sufficient. We characterize completely the
extreme points of L_(2,2) and L(3,2), i.e. quantum channels from qubits to
qubits and from qutrits to qubits.Comment: Slightly revised version, 19 page
Formulation of a dynamic analysis method for a generic family of hoop-mast antenna systems
Analytical studies of mast-cable-hoop-membrane type antennas were conducted using a transfer matrix numerical analysis approach. This method, by virtue of its specialization and the inherently easy compartmentalization of the formulation and numerical procedures, can be significantly more efficient in computer time required and in the time needed to review and interpret the results
Composite structural materials
Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented
Composite structural materials
A decade long program to develop critical advanced composite technology in the areas of physical properties, structural concept and analysis, manufacturing, reliability, and life predictions is reviewed. Specific goals are discussed. The status of the chemical vapor deposition effects on carbon fiber properties; inelastic deformation of metal matrix laminates; fatigue damage in fibrous MMC laminates; delamination fracture toughness in thermoplastic matrix composites; and numerical analysis of composite micromechanical behavior are presented
Composite structural materials
Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed
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