Using Path Integral Monte Carlo, we have calculated exchange frequencies as electrons undergo ring exchanges of 2, 3, and 4 electrons in a “clean” 3D Wigner crystal (bcc lattice) as a function of density. We find pair exchange dominates and estimate the critical temperature for the transition to antiferromagnetic ordering to be roughly 1310−8 Ry at melting. In contrast to the situation in 2D, t...

Persistent currents in mesoscopic metallic rings induced by static magnetic fields are investigated by means of a Hamiltonian which incorporates diagonal disorder and the electron-electron interaction through a Hubbard term (U). Correlations are included up to second order perturbation theory which is shown to work accurately for U of the order of the hopping integral. If disorder is not very s...

High current and stringent restrictions on beam losses in the designed linac and storage ring for the Spallation Neutron Source (SNS) require clean and fast – with the rise time from 2% to 98% less than 2.5 ns – beam chopping in the linac front end, at the beam energy 2.5 MeV. The development of new traveling-wave deflecting current structures, based on meander lines, for the SNS fast chopper i...

I begin with the proposition that eating is an agricultural act. Eating ends the annual drama of the food economy that begins with planting and birth. Most eaters, however, are no longer aware that this is true. They think of food as an agricultural product, perhaps, but they do not think of themselves as participants in agriculture. They think of themselves as “consumers.” If they think beyond...

A study is presented of a possible future measurement of the longitudinal structure function FL(x,Q ) with different proton beam energies at HERA. To appear in the proceedings of the workshop “Future Physics at HERA”, DESY, Hamburg, 1996. Future Measurement of the Longitudinal Proton Structure Function at HERA L.A.T. Bauerdick, A. Glazov, M. Klein a DESY, Notkestraße 85, D-22607 Hamburg, German...

3.1 PRODUCTION OF CLEAN SYNTHESIS GAS......................................................................... 9 3.1.1 Biomass Gasification .............................................................................................. 9 3.1.2 Gas Cleanup.......................................................................................................... 10 3.2 CONVERSION OF SYNTHESIS GAS T...

This paper is intended as a first step in a program for a full algorithmic enumeration of lattice 3-polytopes. The program is based in the following two facts, that we prove: • For each n there is only a finite number of (equivalence classes of) 3polytopes of lattice width larger than one, where n is the number of lattice points. Polytopes of width one are infinitely many, but easy to classify....

High resolution RADAR images of contiguous targets like vehicles on road often suffer from side lobe enhancement. This leads to false alarm in target detection and degradation in image quality. In this paper, adaptive CLEAN algorithms are introduced to eliminate side lobe enhancement and significantly improve the target detection with better image quality. The effectiveness of the CLEAN algorit...

Multipath propagation in the interstellar medium distorts radio pulses, an effect predominant for distant pulsars observed at low frequencies. Typically, broadened pulses are analyzed to determine the amount of propagation-induced pulse broadening, but with little interest in determining the undistorted pulse shapes. In this paper we develop and apply a method that recovers both the intrinsic p...

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