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S. Della Negra H. Gauvin H. Jungclas Y. Le Beyec M. Lefort 《Zeitschrift für Physik A Hadrons and Nuclei》1977,282(1):65-73
Excitation functions have been drawn for evaporation residues issued from150Gd, a compound nucleus produced either by16O ions on134Ba, or by40Ar on110Pd. Absolute cross sections were measured for145–147Gd,145–147Eu,141m Sm,143m Sm,140m Pm and139m Nd. Complete fusion cross sections have been obtained and compared to calculated estimations based, at low energies, on the simple expressionσ CF=πR Fuss 2 (1?V Fus/E) whereR Fus andV Fus are respectively the distance and the potential for fusion atdV/dr=0. For high energies σCF=πR cr 2 (1?Vcr/E) with the model of critical distanceR cr and critical potentialV cr. Thresholds energies have been determined with a particular care. The analysis of the shape and the width of excitation functions, particularly for the emission of 4 and 5 neutrons, has been carried out and compared to calculated values. The difference between argon and oxygen induced reactions has been attributed to the difference inl population in the entrance channel. 相似文献
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D. Drijard H. G. Fischer W. Geist P. G. Innocenti V. Korbel A. Minten A. Norton S. Stein O. Ullaland H. D. Wahl G. Fontaine C. Ghesquière G. Sajot P. Hanke W. Hofmann M. Panter K. Rauschnabel J. Spengler D. Wegener H. Frehse M. Heiden E. E. Kluge A. Putzer M. Della Negra D. Linglin R. Gokieli R. Sosnowski 《Zeitschrift fur Physik C Particles and Fields》1981,9(4):293-303
Inclusive production of ?0,f, andg 0 mesons and ofK s 0 ,K *0 (892), ? andK *0(1430)mesons has been measured at <y>~2.6 and <p T >~1.1 GeV/c in proton-proton interactions at \(\sqrt s = 52.5\) GeV. The negative particle from the two-body decays of these resonances were identified by a threshold Cerenkov counter and used for triggering. Starting from the measured differential cross section, total inclusive cross sections for the vector and tensor mesons were determined using various parametrizations for they andp T dependence of the differential cross section. The experimental results are discussed in the framework of production models based on the parton picture. The strangeness suppresion factor λ=(0.30±0.10) due toSU(3) symmetry breaking of the quark sea is derived. 相似文献
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M. Della Negra D. Drijard H.G. Fischer G. Fontaine H. Frehse P. Frenkiel C. Chesquiere R. Gokieli P. Hanke W. Hofmann W. Isenbeck E.E. Kluge V. Korbel D. Linglin A. Minten A. Norton A. Putzer R. Sosnowski D. Wegener 《Physics letters. [Part B]》1976,65(4):394-396
The reaction pp→ppπ+π? at √s=31GeV was studied at the Split Field Magnet Facility of the CERN-ISR. Selecting events with two leading protons of x>0.9 and a rapidity gap Δy>2 between the protons and both pions a sample of 720 events is obtained representing a cross section of 25±10μb. The mass distribution of the dipion system, x and pT distributions for the protons are presented and analyzed for the presence of double pomeron exchange. 相似文献
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S. Della Negra H. Gauvin H. Jungclas Y. Le Beyec M. Lefort 《Zeitschrift für Physik A Hadrons and Nuclei》1977,282(1):75-82
The deexcitation of the compound nucleus150Gd formed by156O+134Ba and40Ar+110Pd have been studied. Excitation functions were determined for various exit channels: (HI, × n) withx=3, 4, 5 (HI, pxn) withx=2, 3, 4 (HI, axn) withx=3 and 5. A systematic comparison has been made between these experimental data and the results of evaporation calculation using the ALI CE code. The very good agreement obtained for the total residue cross section disappears completely when a more detailed analysis of the different contributions is performed. Absolute and relative cross sections are not reproduced; excitation functions of each individual channel (HI, 3n), (HI, 4n) etc. ... are not found at the right place in energy. A very preliminary explanation for such a shift towards higher energies is suggested. 相似文献
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M. Della Negra D. Drijard H.G. Fischer G. Fontaine H. Frehse P. Frenkiel G. Ghesquière R. Gokieli P. Hanke P.G. Innocenti W. Isenbeck E.E. Kluge V. Korbel S. Krzywdzinski D. Linglin A. Minten D.R.O. Morrison A. Putzer D. Wegener 《Physics letters. [Part B]》1975,59(4):401-404
Events with a positive particle of large transverse momentum emitted at medium angles have been studied using the split field magnet spectrometer at the CERN-ISR at a c.m. energy of √s = 52.5 GeV. Positive particles with large longitudinal momentum, |x| > 0.5, i.e., leading particles, associated to large pT events, are analysed. 相似文献
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S. Della Negra D. Jacquet Y. Le Beyec 《Zeitschrift für Physik A Hadrons and Nuclei》1982,308(3):243-246
Neutron deficient isotopes of86Nb,87Nb,87Mo and88Mo have been produced and identified. Their total decay positron energy have been measured and used to deduce mass excesses. 相似文献
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Mapping Dicorynia guianensis Amsh. wood constituents by submicron resolution cluster‐TOF‐SIMS imaging 下载免费PDF全文
Quentin P. Vanbellingen Tingting Fu Claudia Bich Nadine Amusant Didier Stien Serge Della‐Negra David Touboul Alain Brunelle 《Journal of mass spectrometry : JMS》2016,51(6):412-423
The preparation of tropical wood surface sections for time‐of‐flight secondary ion mass spectrometry imaging is described, and the use of delayed extraction of secondary ions and its interest for the analysis of vegetal surface are shown. The method has been applied to the study by time‐of‐flight secondary ion mass spectrometry imaging with a resolution of less than one micron of a tropical wood species, Dicorynia guianensis, which is one of the most exploited wood in French Guiana for its durable heartwood. The heartwood of this species exhibits an economical importance, but its production is not controlled in forestry. Results show an increase of tryptamine from the transition zone and a concomitant decrease of inorganic ions and starch fragment ions. These experiments lead to a better understanding of the heartwood formation and the origin of the natural durability of D. guianensis. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Signorini Raffaella Meneghetti Moreno Bozio Renato Brusatin Giovanna Innocenzi Plinio Guglielmi Massimo Negra Federico Della 《Journal of Sol-Gel Science and Technology》2001,22(3):245-253
Hybrid organic-inorganic materials are investigated as suitable materials for inclusion of fullerene derivatives and for fabrication of laser protection devices. A specific synthesis has been developed in order to optimize non-linear optical performances of fullerene derivatives. 3-glicydoxypropyltrymethoxysilane has been used as an inorganic and organic network former to obtain the host material. The sol-gel synthesis consists of the hydrolysis and condensation in acidic conditions of the inorganic network. Epoxy polymerization has been achieved by using zirconium or BF3 alkoxides precursors. Bulk and multilayer materials doped with a fullerene derivative have been fabricated. They show good optical requirements: high fullerenes concentration, high microstructural homogeneity, high laser damage threshold and high optical limiting efficiency. Optical limiting (OL) mechanisms have been investigated. The most effective in the sol-gel materials is the reverse saturable absorption (RSA) one. However, different mechanisms, like non-linear (NL) scattering and NL refraction contribute to a different extent. Open- and closed-aperture OL and z-scan measurements on sol-gel samples show the contribution of NL scattering and NL refraction at 690 nm. Laser damage threshold has been characterized as a function of the structure of the samples and of the optical configurations (f/66 and f/5). 相似文献