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171.
172.
"电场生物学效应"引入大学物理实验教学的探讨 总被引:1,自引:1,他引:0
为培养学生创新意识和能力,实现物理实验教学现代化,本文介绍了将“电场生物学效应”科研工作中取得的部分成果引入大学物理实验教学的一些尝试。 相似文献
173.
The production of
and
charmonium states in proton-nucleus interactions has been investigated by the NA50 experiment, at the CERN SPS. High statistics data sets were collected with collisions induced by 450 GeV protons incident on Be, Al, Cu, Ag and W targets. The
and
production cross-sections have been determined for each p-A system and their dependences on the nucleus size have been studied, leading to the so-called normal nuclear absorption. Comparing the two patterns we see that the nuclear absorption is stronger for the
than for the
. Given the high statistics of the data samples, the
(or rapidity) differential cross-sections of the
and
states have also been studied, for each of the target nuclei.Received: 23 September 2003, Revised: 29 November 2003, Published online: 29 January 2004 相似文献
174.
M. Guanziroli D. A. Jensen P. Le Coultre H. Suter V. L. Telegdi K. Freudenreich A. Ereditato P. Strolin P. Bordalo Ph. Busson L. Kluberg A. Romana R. Salmeron C. Vallée J. J. Blaising A. Degre P. Juillot R. Morand M. Winter NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,37(4):545-556
We present the angular distributions of high-mass muon pairs produced in a high-statistics experiment by 140 and 194 GeV/c π? beams impinging on a tungsten target, and by 286 GeV/c π? beam on deuterium and tungsten targets. We find no evidence for a center-of-mass energy dependence or a nuclear dependence of the angular distribution parameters. The two parameters λ and μ are found to be essentially independent of any kinematical variable. In contrast, the parameterv increase with the dimuon transverse momentumP T , at variance with recent perturbative QCD predictions. Our statistics at largex 1 are insufficient to substantiate the highertwist prediction. 相似文献
175.
M. Adamus I. V. Ajinenko Yu. A. Belokopytov V. A. Berezhnoy H. B?ttcher P. V. Chliapnikov F. Crijns A. De Roeck E. A. De Wolf K. Dziunikowska A. M. F. Endler P. F. Ermolov A. Eskreys H. Graessler R. Sh. hakobyan P. van Hal T. Haupt L. P. Kishinevskaya W. Kittel A. I. Kurnosenko B. B. Levchenko J. M?kela F. Meijers A. B. Micha?owska V. I. Nikolaenko L. C. S. Oliveira K. Olkiewicz E. Riipinen H. F. Roloff V. M. Ronjin A. M. Rybin H. M. T. Saarikko W. Schmitz L. Scholten J. Stepaniak O. G. Tchikilev A. G. Tomaradze V. A. Uvarov F. Verbeure R. Wischnewski S. A. Zotkin EHS/NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,37(3):347-355
Two-pion correlations are studied for pions of like charge inK + p andπ + p collisions at 250 GeV/c. An enhanced production is observed at small momentum difference and is attributed to Bose-Einstein interference between identical particles. A systematic study is presented on the influence of parametrization and reference sample. Interpreted in terms of the Kopylov-Podgoretskii parametrization a size of the emitting regionr K ≈1.4 fm is found. The Lorentz invariant parametrization of Goldhaber givesr G ≈0.8 fm. With fixed parametrization, similarity is found for hadronhadron,e + e ? and lepton-hadron collisions. No multiplicity or angular dependence is found at our energy. 相似文献
176.
I. V. Ajinenko L. Albert Yu. A. Belokopytov H. Bia?kowska H. B?ttcher F. Botterweck P. V. Chliapnikov F. Crijns A. De Roeck E. A. De Wolf K. Dziunikowska A. M. F. Endler Z. C. Garutchava U. G. Gavrjusev R. C. Hacobyan P. van Hal T. Haupt D. Kisielewska W. Kittel S. S. Megrabyan F. Meijers A. B. Micha?owska V. I. Nikolaenko K. Olkiewicz V. M. Ronjin A. M. Rybin H. M. T. Saarikko L. Scholten E. K. Shabalina O. G. Tchikilev V. A. Uvarov F. Verbeure R. Verbist R. Wischnewski Yu. V. Yarba EHS/NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1990,46(4):525-536
The inclusive production of neutral kaons is studied inK + p and π+ p interactions at 250 GeV/c. Total and semi-inclusive cross sections and average kaon multiplicities are presented and compared with the data at lower energies. The longitudinal and transverse momentum distributions and their energy dependence are analyzed. The results are interpreted in the framework of recent parton models. 相似文献
177.
J. Badier J. Boucrot J. Bourotte G. Burgun O. Callot Ph. Charpentier M. Crozon D. Decamp P. Delpierre B. Gandois R. Hagelberg M. Hansroul Y. Karyotakis W. Kienzle P. Le D? J. Lefran?ois Th. Leray J. Maillard A. Michelini Ph. Miné G. Rahal O. Runolfsson P. Siegrist A. Tilquin J. Timmermans J. Valentin S. Weisz NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1983,20(2):101-116
A detailed study ofJ/ψ hadronic production has been performed in a high statistics experiment (more than 1.5 106 J/ψ observed in their dimuon decay mode). Data have been taken with incident π±,K ±,p ±, on hydrogen and platinum targets, at 150, 200 and 280 GeV/c. We find from the observed nuclear dependance of the cross sections, that about 18% of theJ/ψ are produced diffractively. Using known structure functions of the quarks in the nucleon and in the pion, we derive estimations for the gluon structure functions. 相似文献
178.
B. Betev J. J. Blaising P. Bordalo A. Boumediene L. Cerrito A. Degré A. Ereditato S. Falciano K. Freudenreich E. Gorini M. Guanziroli H. Hofer P. Juillot L. Kluberg P. Lecomte P. Le Coultre R. Morand B. Mours A. Romana R. Salmeron P. Strolin H. Suter V. L. Telegdi J. Varela G. Viertel J. Wallace-Hadrill M. Winter NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1985,28(1):9-14
179.
J. Allday J. R. Fry P. Mason G. D. Patel F. Meijers W. J. Metzger C. De Marzo M. De Palma C. Favuzzi G. Maggi F. Posa A. Ranieri G. Selvaggi P. Spinelli P. Malecki K. Olkiewicz P. Stopa I. Derado V. Eckardt J. Fent P. Freund H. J. Gebauer A. Manz K. P. Pretzl N. Schmitz P. Seyboth J. Seyerlein G. Wolf NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,40(1):29-39
The results of an analysis of streamer chamber data from the NA5 experiment are presented. Topological cross sections forpp and \(\bar p\) p interactions and strange neutral particle production at 200 GeV/c have been measured and ( \(\bar p\) p?pp) difference cross sections have been determined. Multiplicity moments were calculated. 相似文献
180.
Synthesis characterization of niobium-promoted cobalt/iron catalysts supported on carbon nanotubes for the hydrogenation of carbon monoxide 《燃料化学学报》2016,44(7):815-821
Bimetallic Co /Fe catalysts supported on carbon nanotubes( CNTs) were prepared,and niobium( Nb) was added as promoter to the 70 Co ∶30Fe /CNT catalyst. The physicochemical properties of the catalysts were characterized,and the catalytic performances were analyzed at the same operation conditions( H_2 ∶CO( volume ratio) = 2 ∶1,p = 1 MPa,and t = 260 ℃) in a tubular fixed-bed microreactor system. The addition of Nb to the bimetallic catalyst decreases the average size of the oxide nanoparticles and improves the reducibility of the bimetallic catalyst. Evaluation of the catalyst performance in a Fischer-Tropsch reaction shows that the catalyst results in high selectivity to methane,and the selectivity to C_(5+) increased slightly in the bimetallic catalyst unlike that in the monometallic catalysts. The addition of 1% Nb to the bimetallic catalyst increases CO conversion and selectivity to C_(5+). Meanwhile,a decrease in methane selectivity is observed. 相似文献