26 research outputs found
The Flux-Line Lattice in Superconductors
Magnetic flux can penetrate a type-II superconductor in form of Abrikosov
vortices. These tend to arrange in a triangular flux-line lattice (FLL) which
is more or less perturbed by material inhomogeneities that pin the flux lines,
and in high- supercon- ductors (HTSC's) also by thermal fluctuations. Many
properties of the FLL are well described by the phenomenological
Ginzburg-Landau theory or by the electromagnetic London theory, which treats
the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft
mainly because of the large magnetic penetration depth: The shear modulus of
the FLL is thus small and the tilt modulus is dispersive and becomes very small
for short distortion wavelength. This softness of the FLL is enhanced further
by the pronounced anisotropy and layered structure of HTSC's, which strongly
increases the penetration depth for currents along the c-axis of these uniaxial
crystals and may even cause a decoupling of two-dimensional vortex lattices in
the Cu-O layers. Thermal fluctuations and softening may melt the FLL and cause
thermally activated depinning of the flux lines or of the 2D pancake vortices
in the layers. Various phase transitions are predicted for the FLL in layered
HTSC's. The linear and nonlinear magnetic response of HTSC's gives rise to
interesting effects which strongly depend on the geometry of the experiment.Comment: Review paper for Rep.Prog.Phys., 124 narrow pages. The 30 figures do
not exist as postscript file
Determining the anterior-posterior extent of the rat Posterior Parietal Cortex
This paper identifies a location defining the anterior-posterior (AP)
boundaries of the posterior parietal cortex (PPC) in the rat brain. The PPC
receives information from neuronal connections in various regions of the brain;
the regions directly anterior and posterior to the PPC likewise receive
information from neurons, but from connections in different brain regions. Two
retrograde tracers were injected along the AP axis into sites in and around the
PPC. The location of the border between the PPC and neighboring regions can
be determined as lying between the two injection sites if the two tracers move to
different brain regions as this indicates that the injection sites were not both in
the same region, but rather straddle the border. Results are analyzed from a
series of repeated experiments in which a pair of injection sites were targeted to
straddle the border between PPC and the neighboring region, secondary visual
cortex (V2). Improvements to the method used are then addressed to aid future
experimentation
An extensible framework for providing dynamic data structure visualizations in a lightweight IDE
A framework for producing dynamic data structure visualizations within the context of a lightweight IDE is described. Multiple synchronized visualizations of a data structure can be created with minimal coding through the use of an external viewer model. The framework supplies a customizable viewer template as well as high-level APIs to a graph drawing library and the Java Debugger Interface. Initial classroom use has demonstrated the framework’s ease of use as well as its potential to as an aid to student learning
Visual Support for Incremental Abstraction and Refinement in Ada 95 - by
GRASP is a software engineering tool which uniquely combines a source code diagramming technique, the control structure diagram (CSD), with other comprehension aids such as complexity visualization, syntax coloring and source code folding. The synergistic combination of these features in GRASP has the potential to be a powerful aid in any activity where source code is expected to be read. The primary focus of GRASP is to improve the comprehension efficiency of software and, as a result, improve reliability and reduce costs during design, implementation, testing, maintenance and reengineering. 1.1 Keywords Software visualization, folding, program understandin