Nano-Engineering Defect Structures on Graphene

We present a new way of nano-engineering graphene using defect domains. These regions have ring structures that depart from the usual honeycomb lattice, though each carbon atom still has three nearest neighbors. A set of stable domain structures is identified using density functional theory (DFT), including blisters, ridges, ribbons, and metacrystals. All such structures are made solely out of carbon; the smallest encompasses just 16 atoms. Blisters, ridges and metacrystals rise up out of the sheet, while ribbons remain flat. In the vicinity of vacancies, the reaction barriers to formation are sufficiently low that such defects could be synthesized through the thermally activated restructuring of coalesced adatoms.Comment: 4 pages, 5 figure

Engineering and Manipulating Exciton Wave Packets

When a semiconductor absorbs light, the resulting electron-hole superposition amounts to a uncontrolled quantum ripple that eventually degenerates into diffusion. If the conformation of these excitonic superpositions could be engineered, though, they would constitute a new means of transporting information and energy. We show that properly designed laser pulses can be used to create such excitonic wave packets. They can be formed with a prescribed speed, direction and spectral make-up that allows them to be selectively passed, rejected or even dissociated using superlattices. Their coherence also provides a handle for manipulation using active, external controls. Energy and information can be conveniently processed and subsequently removed at a distant site by reversing the original procedure to produce a stimulated emission. The ability to create, manage and remove structured excitons comprises the foundation for opto-excitonic circuits with application to a wide range of quantum information, energy and light-flow technologies. The paradigm is demonstrated using both Tight-Binding and Time-Domain Density Functional Theory simulations.Comment: 16 figure

Embedded Ribbons of Graphene Allotropes: An Extended Defect Perspective

Four fundamental dimer manipulations can be used to produce a variety of localized and extended defect structures in graphene. Two-dimensional templates result in graphene allotropes, here viewed as extended defects, which can exhibit either metallic or semiconducting electrical character. \emph{Embedded allotropic ribbons}--i.e. thin swaths of the new allotropes--can also be created within graphene. We examine these ribbons and find that they maintain the electrical character of their parent allotrope even when only a few atoms in width. Such extended defects may facilitate the construction of monolithic electronic circuitry.Comment: 24 pages, 21 figure

THE OSTEOLOGY OF ALIORAMUS, A GRACILE AND LONG-SNOUTED TYRANNOSAURID (DINOSAURIA: THEROPODA) FROM THE LATE CRETACEOUS OF MONGOLIA

Fig. 68: Closeup of right ilium of the holotype specimen of Alioramus altai (IGM 100/1844) in lateral view. Scale bar 5 5 cm. Abbreviations as in figure 66.Published as part of Brusatte, Stephen L., Carr, Thomas D. & Norell, Mark A., 2012, The Osteology Of Alioramus, A Gracile And Long-Snouted Tyrannosaurid (Dinosauria: Theropoda) From The Late Cretaceous Of Mongolia, pp. 1-197 in Bulletin of the American Museum of Natural History 2012 (366) on page 149, DOI: 10.1206/770.1, http://zenodo.org/record/539926

Exact Dynamics of Multicomponent Bose-Einstein Condensates in Optical Lattices in One, Two and Three Dimensions

Numerous exact solutions to the nonlinear mean-field equations of motion are constructed for multicomponent Bose-Einstein condensates on one, two, and three dimensional optical lattices. We find both stationary and nonstationary solutions, which are given in closed form. Among these solutions are a vortex-anti-vortex array on the square optical lattice and modes in which two or more components slosh back and forth between neighboring potential wells. We obtain a variety of solutions for multicomponent condensates on the simple cubic lattice, including a solution in which one condensate is at rest and the other flows in a complex three-dimensional array of intersecting vortex lines. A number of physically important solutions are stable for a range of parameter values, as we show by direct numerical integration of the equations of motion.Comment: 22 pages, 9 figure

Defect Engineering: Graphene Gets Designer Defects

An extended one-dimensional defect that has the potential to act as a conducting wire has been embedded in another perfect graphene sheet.Comment: 2 pages, 1 figur

The Geology of Kansas—Arbuckle Group

Cambrian-Ordovician Arbuckle Group rocks in Kansas occur entirely in the subsurface. As is demonstrated throughout this paper, the historical and current understanding of the Arbuckle Group rocks in Kansas has in large part been dependent on petroleum-industry philosophies, practices, and trends. The widely accepted conceptual model of Arbuckle reservoirs as an unconformity play guided drilling and completion practices in which wells were drilled into the top of the Arbuckle with relatively short penetration (under 10 to 50 ft) deeper into the Arbuckle. This resulted in very little log or core data available from the Arbuckle interval. In addition, due to the early development (1917-1940) of the majority of Arbuckle reservoirs, log and geophysical data are not up to modern standards. Over the last few decades, deep penetrating wells have been drilled into the Arbuckle accompanied by full modern log suites and drill-stem tests. However, little corresponding core has been taken to calibrate the logs, and no detailed studies have been conducted to date on the more extensive, modern log data. Thus, data and detailed understanding of Arbuckle Group strata in Kansas are lacking relative to Arbuckle and age-equivalent strata from other areas in the United States, especially those where Arbuckle strata crop out. However, Arbuckle Group strata remain an important reservoir target in Kansas, and our understanding of the unit will increase with continued studies that incorporate modern data, techniques, and approaches