Electronic structure of the (111) and (-1-1-1) surfaces of cubic BN: A local-density-functional ab initio study

We present ab initio local-density-functional electronic structure calculations for the (111) and (-1-1-1) surfaces of cubic BN. The energetically stable reconstructions, namely the N adatom, N3 triangle models on the (111), the (2x1), boron and nitrogen triangle patterns on the (-1-1-1) surface are investigated. Band structure and properties of the surface states are discussed in detail.Comment: 8 pages, 12 figure

Large-Scale Simulations of Melting in Two-Dimensional Lennard-Jones Systems: Evidence for a Metastable Hexatic Phase

In 1995, North Americans installed $5 billion in efficiency equipment in their buildings in order to save money and conserve energy and water. But this covers only a small fraction of the existing cost-effective opportunities for energy savings investments. If all cost-effective efficiency investments were made in public and commercial buildings, the United States would save$20 billion per year on energy bills, create over 100,000 jobs, and significantly cut pollution. When firms invest in energy efficiency, they naturally want to know how much they have saved and how long their savings will last. If the installation had been made to generate energy, measurements would be trivial - install a meter. But to measure savings is a challenge, and requires both metering and a methodology, known as a measurement and verification protocol. To determine energy savings, the parties (the building owner, the installer and perhaps the financier) must first agree on the {open_quotes}base case{close_quotes} (what the building used before retrofit), and then must measure energy use after retrofit. They may want to adjust the savings for variations in the weather or changes in occupancy or work schedules. And they should keep up the measurements to ensure that their savings persist