Comment on: Weak Anisotropy and Disorder Dependence of the In-Plane Magnetoresistance in High-Mobility (100) Si Inversion Layers

Comment on: Weak Anisotropy and Disorder Dependence of the In-Plane Magnetoresistance in High-Mobility (100) Si Inversion LayersComment: 1 page, submitted to PR

Magnetoresistance of a two-dimensional electron gas in a parallel magnetic field

The conductivity of a two-dimensional electron gas in a parallel magnetic field is calculated. We take into account the magnetic field induced spin-splitting, which changes the density of states, the Fermi momentum and the screening behavior of the electron gas. For impurity scattering we predict a positive magnetoresistance for low electron density and a negative magnetoresistance for high electron density. The theory is in qualitative agreement with recent experimental results found for Si inversion layers and Si quantum wells.Comment: 4 pages, figures included, PDF onl

Technology utilization in a non-urban region: Further impact and technique of the Technology Use Studies Center

Updated information pertaining to clients who receive and use information disseminated by the Technology Use Studies Center (TUSC) is reported. Charts are provided which indicate TUSC's performance in information dissemination and technical assistance in terms of quantities of searches accomplished during several contract years. The faculty information service is described, along with details of cooperation with other agencies. Specific searches are listed according to subject, client, and client location, and a measure of client response to services provided is indicated by the included selection of transfer and impact reports. The impetus behind the formation of the general aviation news letter is also described

Technology utilization

Documentation is presented for selected transfer and impact reports provided to the business community, government agencies, and such other requestors as schools, universities, and health services. Statistical data are also included on the characteristics of the TUSC technical searches

Technology utilization data searches

Technology Use Studies Center activities, functions, and services are reported for this period. Transfers and searches are described. Characteristics of TUSC searches are tabulated

Technology utilization in a non-urban region: Further impact and technique of the Technology Use Studies Center, 2

The clientele served by the Technology Use Studies Center (TUSC) is updated. Manufacturing leads the list of client firms. The standard industrial classification (SIC) range of these firms is broad. Substantial numbers of college and university faculties are using TUSC services. Field operations inherent in the functions of dissemination and assistance are reviewed. Increasing emphasis among clientele is on environmental concerns and management. A record is provided of the institutions contacted and the extent of TUSC involvement with them, as well as TUSC's cooperation with agencies and organizations. The impact of TUSC and the NASA-sponsored Technology Utilization Program on other public agencies is discussed

Search and dissemination in data processing

Manual retrieval methods were used to complete 54 searches of interest for the General Aviation Newsletter. Subjects of search ranged from television transmission to machine tooling, Apollo moon landings, electronic equipment, and aerodynamics studies

Scaling analysis of the magnetic-field-tuned quantum transition in superconducting amorphous In-O films

We have studied the magnetic-field-tuned superconductor-insulator quantum transition (SIT) in amorphous In-O films with different oxygen content and, hence, different electron density. While for states of the film near the zero-field SIT the two-dimensional scaling behaviour is confirmed, for deeper states in the superconducting phase the SIT scenario changes: in addition to the scaling function that describes the conductivity of fluctuation-induced Cooper pairs, there emerges a temperature-dependent contribution to the film resistance. This contribution can originate from the conductivity of normal electrons.Comment: 4 pages, 5 figures; accepted for publication in JETP Lett. 71 (4), 200

Evolution of Quantum Criticality in CeNi_{9-x}Cu_xGe_4

Crystal structure, specific heat, thermal expansion, magnetic susceptibility and electrical resistivity studies of the heavy fermion system CeNi_{9-x}Cu_xGe_4 (0 <= x <= 1) reveal a continuous tuning of the ground state by Ni/Cu substitution from an effectively fourfold degenerate non-magnetic Kondo ground state of CeNi_9Ge_4 (with pronounced non-Fermi-liquid features) towards a magnetically ordered, effectively twofold degenerate ground state in CeNi_8CuGe_4 with T_N = 175 +- 5 mK. Quantum critical behavior, C/T ~ \chi ~ -ln(T), is observed for x about 0.4. Hitherto, CeNi_{9-x}Cu_xGe_4 represents the first system where a substitution-driven quantum phase transition is connected not only with changes of the relative strength of Kondo effect and RKKY interaction, but also with a reduction of the effective crystal field ground state degeneracy.Comment: 15 pages, 9 figure

"Propeller" Regime of Disk Accretion to Rapidly Rotating Stars

We present results of axisymmetic magnetohydrodynamic simulations of the interaction of a rapidly-rotating, magnetized star with an accretion disk. The disk is considered to have a finite viscosity and magnetic diffusivity. The main parameters of the system are the star's angular velocity and magnetic moment, and the disk's viscosity, diffusivity. We focus on the "propeller" regime where the inner radius of the disk is larger than the corotation radius. Two types of magnetohydrodynamic flows have been found as a result of simulations: "weak" and "strong" propellers. The strong propeller is characterized by a powerful disk wind and a collimated magnetically dominated outflow or jet from the star. The weak propeller have only weak outflows. We investigated the time-averaged characteristics of the interaction between the main elements of the system, the star, the disk, the wind from the disk, and the jet. Rates of exchange of mass and angular momentum between the elements of the system are derived as a function of the main parameters. The propeller mechanism may be responsible for the fast spinning-down of the classical T Tauri stars in the initial stages of their evolution, and for the spinning-down of accreting millisecond pulsars.Comment: 18 pages, 16 figures, ApJ (accepted), added references, corrected typos; see animation at http://astrosun2.astro.cornell.edu/us-rus/disk_prop.ht