Design of a magnetostrictive (MS) actuator

Several advanced technologies are introduced in automotive applications. Higher energy density and dynamic performance are demanding new and cost effective actuator structures. Magnetostriction (MS), change in shape of materials under the influence of an external magnetic field, is one of these advanced technologies. Good understanding of specific design constrains is required to define and optimized a magnetostrictive actuator. This paper presents parametrical analysis with magnetic simulation of a magnetostrictive actuator. Proposed actuator has been designed, and the performance has been evaluated on experimental rig. Strain, elongation of the shaft, of 1000ppm at 10Amp and a blocked force over 4500N has been achieved with shaft of 8mm diameter, made of Terfenol-D. Furthermore, the effect of pre-stress of the Terfenol-D shaft has been evaluated experimentally. The study shows that excellent features can be obtained by magnetostrictive materials for many advanced applications

Federal Broadband Law

The authors of this book have brought together a vast and varied array of experience. Mr. Thorne is the Vice President & Associate General Counsel for Bell Atlantic; Mr. Huber is a Senior Fellow at the Manhattan Institute for Policy Research; and Mr. Kellogg is a Partner at Kellogg, Huber, Hansen & Todd. A reader will find the occasional use of technical jargon, such as domsats (domestic satellites), coax (coaxial cable), and syndex rules (syndicated exclusivity rules to protect syndicated, non-network programming) to be somewhat confusing. Telcos and cablecos are telephone and cable companies, respectively. Overall, however, technical jargon is well explained for such a comprehensive look at the hightech telecommunications field. After defining the telecosm as the universe of telecommunications and computers, the text moves into a comprehensive technical, regulatory, and legal analysis of the telecosm\u27s short- and long-term future

Charge distribution in two-dimensional electrostatics

We examine the stability of ringlike configurations of N charges on a plane interacting through the potential $V(z_1,...,z_N)=\sum_i |z_i|^2-\sum_{i<j} ln|z_i-z_j|^2$. We interpret the equilibrium distributions in terms of a shell model and compare predictions of the model with the results of numerical simulations for systems with up to 100 particles.Comment: LaTe

Magnetospectroscopy of symmetric and anti-symmetric states in double quantum wells

The experimental results obtained for the magneto-transport in the InGaAs/InAlAs double quantum wells (DQW) structures of two different shapes of wells are reported. The beating-effect occurred in the Shubnikov-de Haas (SdH) oscillations was observed for both types of the structures at low temperatures in the parallel transport when magnetic field was perpendicular to the layers. An approach to the calculation of the Landau levels energies for DQW structures was developed and then applied to the analysis and interpretation of the experimental data related to the beating-effect. We also argue that in order to account for the observed magneto-transport phenomena (SdH and Integer Quantum Hall effect), one should introduce two different quasi-Fermi levels characterizing two electron sub-systems regarding symmetry properties of their states, symmetric and anti-symmetric ones which are not mixed by electron-electron interaction.Comment: 20 pages, 20 figure

Unconventional MBE Strategies from Computer Simulations for Optimized Growth Conditions

We investigate the influence of step edge diffusion (SED) and desorption on Molecular Beam Epitaxy (MBE) using kinetic Monte-Carlo simulations of the solid-on-solid (SOS) model. Based on these investigations we propose two strategies to optimize MBE growth. The strategies are applicable in different growth regimes: During layer-by-layer growth one can exploit the presence of desorption in order to achieve smooth surfaces. By additional short high flux pulses of particles one can increase the growth rate and assist layer-by-layer growth. If, however, mounds are formed (non-layer-by-layer growth) the SED can be used to control size and shape of the three-dimensional structures. By controlled reduction of the flux with time we achieve a fast coarsening together with smooth step edges.Comment: 19 pages, 7 figures, submitted to Phys. Rev.

Focused Ion Beam Fabrication

Contains summary of research program and reports on four research projects.Charles Stark Draper Laboratory (Contract DL-H-225270)Hughes Research LaboratoriesInternational Business Machines, Inc. (Contract 456614)Nippon Telegraph and Telephone, Inc.U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)U.S. Department of Defense (Contract MDA903-85-C-0215)Hitachi Central Research Laborator