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131.
M. A. Forbes J. N. Holt A. M. Watts 《The Journal of the Operational Research Society》1991,42(10):825-831
Given a daily repeating timetable and locomotives of various types, each timetabled train must be assigned a locomotive. This paper presents an exact algorithm for the solution of this problem, based on an approach used to solve multiple-depot bus scheduling problems. The algorithm is used to solve moderately large scheduling problems drawn from real world data. 相似文献
132.
P. Pattison M. Cooper R. Holt J. R. Schneider N. Stump 《Zeitschrift für Physik B Condensed Matter》1977,27(3):205-208
The Compton profiles of Nb and NbH0.76 single crystals have been measured along [100] and [110] using 412 keV gamma-radiation from a198Au source. The changes in the band electron profile of the metal following the introduction of hydrogen are interpreted in terms of the protonic model of the hydride. Qualitative changes in the directional profiles can be understood within the rigid band approximation. 相似文献
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135.
P.J. Bussey J.G. Rutherglen P.S.L. Booth L.J. Carroll G.R. Court A.W. Edwards R. Gamet P.J. Hayman J.R. Holt J.N. Jackson W.H. Range C. Wooff F.H. Combley W. Galbraith A. Phillips V.H. Rajaratnam 《Nuclear Physics B》1979,159(3):383-396
Measurements have been made of the double polarisation parameters G and H in the photoproduction of neutral pions from protons, for incident photon energies between 1300 MeV and 2300 MeV and for pion c.m. angles between 50δ and 80δ. The results are compared with predictions from a recent comprehensive analysis of earlier photoproduction data. 相似文献
136.
The addition of nitrous oxide to a stream of deuterium passing over a rhenium filament reduced the initial sticking probability of the latter gas from 0.24 to 0.09 when the proportion of N2O exceeded 40%. For the addition of deuterium to nitrous oxide the equivalent figures were 0.45 and 0.30 when deuterium exceeded 30% of the gas phase. These results are attributed to a competition between the two gases for places in the precursor state on the surface. The replacement of adsorbed deuterium from a saturated layer by the oxygen atom of nitrous oxide proceeded initially with a high probability, 0.27, at room temperature and with each oxygen atom replacing one deuterium atom. However, the reaction was incomplete, about 2 × 1014 atoms cm?2 of deuterium remaining on the surface. It is suggested that kinetic rather than thermodynamic factors are responsible for the incomplete reaction, possibly as the result of a high activation energy for the migration of deuterium atoms over an oxygenated rhenium surface. 相似文献
137.
Wijesooriya K Afanasev A Amarian M Aniol K Becher S Benslama K Bimbot L Bosted P Brash E Calarco J Chai Z Chang CC Chang T Chen JP Choi S Chudakov E Churchwell S Crovelli D Dieterich S Dumalski S Dutta D Epstein M Fissum K Fox B Frullani S Gao H Gao J Garibaldi F Gayou O Gilman R Glamazdin S Glashausser C Gomez J Gorbenko V Hansen O Holt RJ Hovdebo J Huber GM de Jager CW Jiang X Jones C Jones MK Kelly J Kinney E Kooijman E Kumbartzki G Kuss M LeRose J Liang M Lindgren R Liyanage N Malov S 《Physical review letters》2001,86(14):2975-2979
We present measurements of the recoil proton polarization for the d(gamma-->,p-->)n reaction at straight theta(c.m.) = 90 degrees for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization p(y) vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(gamma,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime. 相似文献
138.
The deposition of ultrasonic energy in tissue can cause tissue damage due to local heating. For pressures above a critical threshold, cavitation will occur, inducing a much larger thermal energy deposition in a local region. The present work develops a nonlinear bubble dynamics model to numerically investigate bubble oscillations and bubble-enhanced heating during focused ultrasound (HIFU) insonation. The model is applied to calculate two threshold-dependent phenomena occurring for nonlinearly oscillating bubbles: Shape instability and growth by rectified diffusion. These instabilities in turn are shown to place physical boundaries on the time-dependent bubble size distribution, and thus the thermal energy deposition. 相似文献
139.
Although semen cryopreservation has been applied successfully in a few species, considerable variation in post-thaw semen viability exists. Independent of sperm quality before freezing, the semen of certain individuals will consistently freeze badly, resulting in poor motility, disrupted acrosome and plasma membrane, and thus reduced fertilising ability, indicating the existence of variation in membrane properties within species. A more comprehensive understanding of sperm cryobiology would be obtained by the investigation of within-species variation in the susceptibility of spermatozoa to cryoinjury. This review aims to explore the phenomenon of consistent variation in frozen semen quality between species and between individuals in an effort to find new insights into the reasons for cryoinjury. Recent studies suggest that there is a genetic basis for variation in post-thaw semen quality, and argue that modern molecular technologies are able to identify markers linked to genes influencing this variation. The identification of genetic differences between individuals, which may be linked to cryosurvival, provides an opportunity to develop a functional and molecular understanding of the factors that influence semen cryopreservation, allowing selective breeding of desired traits and the development of genetic tests that predict the outcome of semen freezing. 相似文献
140.
Schulte EC Ahmidouch A Armstrong CS Arrington J Asaturyan R Avery S Baker OK Beck DH Blok HP Bochna CW Boeglin W Bosted PY Bouwhuis M Breuer H Brown DS Bruell A Cadman RV Carlini R Chant NS Cochran A Cole L Danagoulian S Day DB Dunne JA Dutta D Ent R Fenker HC Fox B Gan L Gao H Garrow K Gaskell D Gasparian A Geesaman DF Gilman R Glashausser C Gueye P Harvey M Holt RJ Jackson HE Jiang X Keppel CE Kinney ER Liang Y Lorenzon W Lung AF Mack DJ Markowitz PE Martin J McIlhany K McKee D Meekins DG 《Physical review letters》2001,87(10):102302
The first measurements of the d(gamma,p)n differential cross section at forward angles and photon energies above 4 GeV were performed at the Thomas Jefferson National Accelerator Facility (JLab). The results indicate evidence of an angular dependent scaling threshold. Results at straight theta(cm) = 37 degrees are consistent with the constituent counting rules for E(gamma) greater, similar 4 GeV, while those at 70 degrees are consistent with the constituent counting rules for E(gamma) greater, similar 1.5 GeV. 相似文献