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991.
A hydrogen ion source designed for the injector of a 16-MeV linear proton accelerator with an average beam current of ∼100
μA is presented. New design approaches allowing an improvement in the operating parameters of the ion source are proposed.
The results of experimental tests of a source prototype operating in a pulsed mode with a repetition rate of 1–10 Hz and pulse
duration of 100–600 μs are described. 相似文献
992.
The near flow field of small aspect ratio elliptic turbulent free jets (issuing from nozzle and orifice) was experimentally
studied using a 2D PIV Two point velocity correla tions in these jets revealed the extent and orientation of the large scale
structures in th e major and minor planes. The spatial filtering of the instantaneous velocity field using Gaussian convolution
kernel shows that while a single large vortex ring circumscribing the jet seems to be present at the exit of nozzle, the orifice
jet exhibited a number of smaller vortex ring pairs close to jet exit. The smaller length scale observed in the case of the
orifice jet is rep resentative of the smaller azimuthal vor tex rings that generate axial vortex field as they are convected.
This results in the axis-switching in th e case of orifice jet and may have a mechanism differ ent from the self induction
process as observed in the case of contoured nozzle jet flow. 相似文献
993.
994.
The FRS-ESR facility at GSI provides one of the most efficient methods for direct mass measurements. In the present experiment,
exotic nuclei were produced via fragmentation of 152Sm projectiles in a thick beryllium target at 500-600 MeV/u, separated in-flight with the fragment separator FRS, and injected
into the storage-cooler ring ESR. Time-resolved Schottky Mass Spectrometry was applied for mass measurements of stored and
electron-cooled bare and few-electron ions. 373 different nuclides were identified by means of the spectra of their revolution
frequencies. Masses for 18 nuclides (84Zr, 92Ru, 94Rh, 107,108,110Sb, 111,112,114I, 118Ba, 122,123La, 124Ce, 127Pr, 129Nd, 132Pm, 134Sm, 137Eu) have been determined for the first time. Masses for 111,112I and 113Xe have been obtained via known α-decay energies. The experiment and first results will be presented. 相似文献
995.
996.
Magnetism of Fe/Cr/Sn/Cr multilayers have been studied by the first-principles density-functional theory. Calculations by the full-potential linearized augmented plane waves (FP LAPW) and screened Korringa–Kohn–Rostoker (SKKR) methods have shown that two types of solutions may be found in these systems: a high-spin (HS) and a low-spin (LS) ones in accordance with the Cr magnetic moment magnitudes. In this work, we have concentrated our attention on the LS solution. The calculation has shown that the LS solution has a phase slip of antiferromagnetic ordering in Cr and is classified as an incommensurate spin density wave (ISDW). The dependence of the ISDW solution on the thickness of Cr, lattice parameter and boundary conditions has been investigated. 相似文献
997.
998.
999.
1000.
Based on the matrix-analytic approach to fluid flows initiated by Ramaswami, we develop an efficient time dependent analysis
for a general Markov modulated fluid flow model with a finite buffer and an arbitrary initial fluid level at time 0. We also
apply this to an insurance risk model with a dividend barrier and a general Markovian arrival process of claims with possible
dependencies in successive inter-claim intervals and in claim sizes. We demonstrate the implementability and accuracy of our
algorithms through a set of numerical examples that could also serve as test cases for comparing other solution approaches.
相似文献