Interface steps in field effect devices

The charge doped into a semiconductor in a field effect transistor (FET) is generally confined to the interface of the semiconductor. A planar step at the interface causes a potential drop due to the strong electric field of the FET, which in turn is screened by the doped carriers. We analyze the dipolar electronic structure of a single step in the Thomas-Fermi approximation and find that the transmission coefficient through the step is exponentially suppressed by the electric field and the induced carrier density as well as by the step height. In addition, the field enhancement at the step edge can facilitate the electric breakthrough of the insulating layer. We suggest that these two effects may lead to severe problems when engineering FET devices with very high doping. On the other hand steps can give rise to interesting physics in superconducting FETs by forming weak links and potentially creating atomic size Josephson junctions.Comment: 6 pages, 4 figures, submitted to J. Appl. Phy

On the naturality of the spectral sequence from Khovanov homology to Heegaard Floer homology

Ozsvath and Szabo have established an algebraic relationship, in the form of a spectral sequence, between the reduced Khovanov homology of (the mirror of) a link L in S^3 and the Heegaard Floer homology of its double-branched cover. This relationship has since been recast by the authors as a specific instance of a broader connection between Khovanov- and Heegaard Floer-type homology theories, using a version of Heegaard Floer homology for sutured manifolds developed by Juhasz. In the present work we prove the naturality of the spectral sequence under certain elementary TQFT operations, using a generalization of Juhasz's surface decomposition theorem valid for decomposing surfaces geometrically disjoint from an imbedded framed link.Comment: 36 pages, 13 figure

On Gradings in Khovanov homology and sutured Floer homology

We discuss generalizations of Ozsvath-Szabo's spectral sequence relating Khovanov homology and Heegaard Floer homology, focusing attention on an explicit relationship between natural Z (resp., 1/2 Z) gradings appearing in the two theories. These two gradings have simple representation-theoretic (resp., geometric) interpretations, which we also review.Comment: 17 pages, 5 figures, to be submitted to Proceedings of Jaco's 70th Birthday Conference, 201

Annoyance due to noise and air pollution to the residents of heavily frequented streets

The residents of different streets with varying traffic density and building density were questioned about annoyance due to traffic noise and air pollution. Results show that annoyance felt is dependent not only on the measured noise levels and/or air pollution concentrations, but that there do exist interactions between the residential quarters and annoyance. These interactions should be considered when fixing the limits and standards

Effects of street traffic noise in the night

The relationship between automobile traffic noise and the degree of disturbance experience experienced at night was explored through a random sample survey of 1600 individuals in rural and urban areas. The data obtained were used to establish threshold values

ARCAID: The ARChitects computer graphics AID

technical reportARCAID?The ARChitect's Computer Graphics AID?is one part of a two-part research program at the University of Utah under the direction of David C. Evans. ARCAID is a specification for the organization of computer processes including data and procedures for the use of architects, engineers, and others in design. As the second part of this research C. Stephen Carr is developing the complex data structure which supports ARCAID. This data structure includes a graphics FORTRAN, a compiler-compiler, an associative memory, and a tree structure for organizing the data for a building scheme. ARCAID is an interactive computer graphics system relying on the Cathode Ray Tube (CRT) for feedback and a typing keyboard, stylus and tablet, trackball, and zoom pedal for input. The picture at the CRT is refreshed by a small computer, and manipulations of alphanumerics and graphic elements are handled by a large computer. ARCAID envisions the design of a building from first briefing and schematics through construction without the use of paper. ARCAID incorporates a computer graphics language called SPACEFORM. I t provides for graphic elements and procedures by which elements are manipulated. The basic graphic elements, "spaceforms," are built up from such primitives as points, lines, and surfaces. Basic spaceforms may be shaped and assembled for more complex (shaped) spaceforms and objects. Proposed manipulations include housekeeping, shaping, assembling, viewing, orienting, and miscellaneous manipulations. Spaceforms are topologically described with respect to geometry and at tributes. By geometric topology the corners, edges, and faces of objects are constrained to retain fixed relationships permitting rotations and other viewing manipulations thereby. By attribute topology the descriptions of objects are also linked to such at tributes as texture, color, weight, and the like