A 1959 * This research has been partially supported by the Fonds National de la Recherche Saentifique and by the Fonds de la Recherche Scientifique Fondamentale Collective. t Predoctoral Fellow of the Institut pour rEncouragement de la Recherche Scientifique dans l'Industrie et F Agriculture 1 A. G. Redfield, Phys. Rev. 98, 1787 (1955). 2 The fixed frame quantities Ho and ED (spin-spin coupling Hamiltonian) are replaced in the rotating frame by H«ff (of the order of Hi) and HD° (that part of HD which commutes with the fixed frame Zeeman Hamiltonian). Spin lattice relaxation will be ignored in the present discussion.
Electron emission following the ionization of projectile ions has been investigated systematically in collisions with Ne~+ and Ar~+ ions at several hundred MeV incident on different target gases. The projectile electrons are concentrated within one maximum, the electron-loss peak (ELP). The variation of the shape and intensity of the ELP with the projectile energy, its charge state, the observation angle, and the target gas has been measured. Theoretical predictions which are based on the binaryencounter approximation show, in general, good agreement with the experimental data. The contributions of the different subshells to the ELP are deduced. It is shown that electronic screening of the target nucleus plays an important role in the ionization process of the projectile ions.
In recent years, many tools have been created to allow software engineers to analyze the execution of their code. While tools such as gprof often work well, most are not integrated very well with each other or the rest of the development environment, and interpreting the data that they provide can be a challenge. Because Apple's MacOS X is based on UNIX, most open source performance analysis tools can be used. However, we have also integrated several key performance tools together and added graphical data visualization to produce the CHUD toolset (Available for at http://developer.apple.com/tools/download/).With the CHUD tools, programmers can examine the performance of their code using a set of integrated tools that can perform most common performance-measurement tasks, including:--Traces of function call behavior (like gprof) --Sampled measurements of program execution timing --Traces of software events, such as system calls --Hardware event counter measurements Moreover, instead of just presenting a few key figures from these measurements in a brief report, the CHUD tools present their results in several textual *and* graphical formats, with integrated hyperlinks to related assembly and source code, so that programmers can easily examine both how their programs work on a large-scale level or zoom in and look at individual program phases in several different ways.This tutorial is targeted primarily at students and software engineers who work on UNIXbased systems and want to expand the repertoire of tools that they can use to analyze and improve the performance of their code. However, the material should also be useful to educators who teach performance-oriented programming techniques, as the graphical nature of Shark's output makes it easy to demonstrate program behaviors in an eye-catching manner.
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