Final State Interactions, T-odd PDFs & the Lensing Function

It has been suggested that under certain approximations the Sivers effect can be described in terms of factorization of final state interactions and a spatial distortion of impact parameter space parton distribution; that is a convolution of the so-called lensing function and the impact parameter GPD $E$. In this approach the lensing function is calculated in a non-perturbative eikonal model. This enables a comparison between the a priori distinct Sivers function and the GPD $E$ which goes beyond the discussion of overall signs.Comment: 5 pages, 5 figures, misprints corrected: To appear in the Proceedings of the 10th Conference on the Intersection of Particle and Nuclear Physics (CIPANP 2009) San Diego, CA, 25-31 May 200

Development of a 1000V, 200A, low-loss, fast-switching, gate-assisted turn-off thyristor

Feasibility was demonstrated for a thyristor that blocks 1000V forward and reverse, conducts 200A, and turns on in little more than 2 microsec with only 2A of gate drive. Its features include a turn-off time of 3 microsec achieved with 2A of gate assist current of a few microseconds duration and an energy dissipation of only 12 mJ per pulse for a 20 microsec half sine wave, 200A pulse. Extensive theoretical and experimental study of the electrical behavior of thyristors having a fast turn-off time have significantly improved the understanding of the physics of turning thyristor off. Thyristors of two new designs were fabricated and evaluated. The high speed and low power were achieved by a combination of gate amplification, cathode shunting, and gate-assisted turn-off. Two techniques for making this combination practical are described

Development of a 1000V, 200A, low-loss, fast-switching, gate-assisted turn-off thyristor

The results of a program to develop a fast high power thyristor that can operate in switching circuits at frequencies of 10 to 20 kHz with very low power loss are given. Feasibility was demonstrated for a thyristor that blocks 1000V forward and reverse, conducts 200A, turns on in little more than 2 more microseconds with only 2A of gate drive, turns off in 3 microseconds with 2A of gate assist current and has an energy dissipation of only 12 mJ per pulse for a 20 microsecond half sine wave 200A pulse. Data were generated that clearly showed the tradeoffs that can be made between the turn off time and forward drop. The understanding of this relationship is necessary in the selection of deliverable thyristors with turn off times up to 7 microseconds to give improved efficiency in a series resonant dc to dc inverter application

Preparation of surface-enhanced resonance Raman scattering-active substrates: applications to heme-containing proteins

Surface-enhanced resonance Raman scattering (SERRS) spectroscopy combines the advantages unique to resonance Raman scattering (RRS) with those of surface-enhanced Raman scattering (SERS). Although much of the initial studies concentrated on elucidating the mechanism (s), considerable attention has recently been directed at exploiting the enormous potential of the technique for analytical and biological purposes. However, the practical applicability of SERRS to many investigations remains limited because experimental conditions corresponding to the effect have not been fully characterized;This problem is especially apparent when SERRS is used for the study of biological systems. In many cases, the biomolecule species is perturbed upon adsorption onto a SERRS-active metal substrate. Hence, SERRS is not a viable method if the resulting spectra correlate to perturbed biological structures. It is the aim of our research to develop procedures for preserving the native structure and activity of proteins at SERRS-active substrates including, silver island-films, electrochemically-roughened silver electrodes, and citrate-reduced sols. In particular, our work has focused on the heme-containing proteins, cytochrome c, cytochrome P-450[subscript] b, myoglobin, and cytochrome c[subscript]3. Depending upon the biomolecule, the native state of the protein can be retained by choosing the appropriate adsorption conditions;Another aspect of our research has been concerned with optimizing and characterizing the experimental parameters in the preparation of SERRS/SERS-active silver-island films. Our results show that for both SERS and SERRS, the intensity of the observed signals is dependent upon the evaporation rate used in the preparation of the silver-island film. The optical densities of the films as well as the resulting surface morphologies were also studied as a function of deposition rate. Specific applications of silver-island films as SERRS-active substrates included Raman microprobe SERRS investigations and the characterization of covalently modified electrodes by using the SERRS technique

Long-Term No-Till in a Wheat-Sorghum-Fallow Rotation

Grain yields of wheat and grain sorghum increased with decreased tillage intensity in a wheat-sorghum-fallow (WSF) rotation. In 2014, available soil water at wheat planting was 2 inches greater for no-till (NT) than for reduced-tillage (RT) or conventional tillage (CT). For grain sorghum in 2014, available soil water at planting was greatest with RT and least with CT. Averaged across the 14-year study, available soil water at wheat and sorghum planting was similar for RT and NT and about 1 inch greater than CT. Averaged across the past 14 years, NT wheat yields were 5 bu/a greater than RT and 7 bu/a greater than CT. Grain sorghum yields in 2014 were 22 bu/a greater with longterm NT than short-term NT. Averaged across the past 14 years, sorghum yields with long-term NT have been nearly twice as great as short-term NT (61 vs. 33 bu/a)