Microscopic theory of single-electron tunneling through molecular-assembled metallic nanoparticles

We present a microscopic theory of single-electron tunneling through metallic nanoparticles connected to the electrodes through molecular bridges. It combines the theory of electron transport through molecular junctions with the description of the charging dynamics on the nanoparticles. We apply the theory to study single-electron tunneling through a gold nanoparticle connected to the gold electrodes through two representative benzene-based molecules. We calculate the background charge on the nanoparticle induced by the charge transfer between the nanoparticle and linker molecules, the capacitance and resistance of molecular junction using a first-principles based Non-Equilibrium Green's Function theory. We demonstrate the variety of transport characteristics that can be achieved through ``engineering'' of the metal-molecule interaction.Comment: To appear in Phys. Rev.

The ultrasonic ranging and data system for radiological surveys in the UMTRA (Uranium Mill Tailings Remedial Action) Project

The Ultrasonic Ranging and Data System (USRADS) was developed to allow radiation exposure data and positional information to be collected, stored and analyzed in a more efficient manner than currently employed on the (Uranium Mill Tailings Remedial Action (UMTRA) project. USRADS is a portable unit which employs ultrasonics, radio frequency transmissions, and a personal computer. Operational experience indicates that the system results in increased information about the property with decreased data analysis and transcription effort and only slightly more field effort. 5 refs., 3 figs., 2 tabs

Application of computers in a Radiological Survey Program

A brief description of some of the applications of computers in a radiological survey program is presented. It has been our experience that computers and computer software have allowed our staff personnel to more productively use their time by using computers to perform the mechanical acquisition, analyses, and storage of data. It is hoped that other organizations may similarly profit from this experience. This effort will ultimately minimize errors and reduce program costs