A topological screening heuristic for low-energy, high-index surfaces

Topological Index Theory for Surfaces in 3-manifolds

The disk complex of a surface in a 3-manifold is used to define its topological index. Surfaces with well-defined topological index are shown to generalize well-known classes, such as incompressible, strongly irreducible, and critical surfaces. The main result is that one may always isotope a surface H with topological index n to meet an incompressible surface F so that the sum of the indices o...

Dirac fermions at high-index surfaces of bismuth chalcogenide topological insulator nanostructures

Binary bismuth chalcogenides Bi2Se3, Bi2Te3, and related materials are currently being extensively investigated as the reference topological insulators (TIs) due to their simple surface-state band dispersion (single Dirac cone) and relatively large bulk band gaps. Nanostructures of TIs are of particular interest as an increased surface-to-volume ratio enhances the contribution of surfaces state...

Conduction-electron screening in the bulk and at low-index surfaces of Ta metal.

A General Index Heuristic for Search wit

This dissertation considers a suite of search problems in which agents are trying to find goals in minimum expected time. Unlike search in data structures in which time is measured by a number operations, search in metric spaces measures time by units of distance and has received much less attention. In particular, search strategies that attempt to minimize expected search time are only availab...

Characterization of low, medium and high energy collimators for common isotopes in nuclear medicine: A Monte Carlo study

Introduction:In an ideal parallel-hole collimator, thickness of septal material should be sufficient to stop more than 95% of incident photons. However, some photons pass the septa without interaction or experience scattering before they reach the detector. In this study, we determined different contribution of collimator responses consist of geometrical response, septal penetr...