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61.
T.R. Saito N. Saito K. Starosta J. Beller N. Pietralla H.J. Wollersheim D.L. Balabanski A. Banu R.A. Bark T. Beck F. Becker P. Bednarczyk K.-H. Behr G. Benzoni P.G. Bizzeti C. Boiano A. Bracco S. Brambilla A. Brünle A. Bürger L. Caceres F. Camera F.C.L. Crespi P. Doornenbal A.B. Garnsworthy H. Geissel J. Gerl M. Górska J. Grebosz G. Hagemann J. Jolie M. Kavatsyuk O. Kavatsyuk T. Koike I. Kojouharov N. Kurz J. Leske G. Lo Bianco A. Maj S. Mallion S. Mandal M. Maliage T. Otsuka C.M. Petrache Zs. Podolyak W. Prokopowicz G. Rainovski P. Reiter A. Richard H. Schaffner 《Physics letters. [Part B]》2008
62.
For ideal nozzles, basically two different types of shock structures in the plume may appear for overexpanded flow conditions, a regular shock reflection or a Mach reflection at the nozzle centreline. Especially for rocket propulsion, other nozzle types besides the ideal nozzles are often used, including simple conical, thrust-optimized or parabolic contoured nozzles. Depending on the contour type, another shock structure may appear: the so-called cap-shock pattern. The exact knowledge of the plume pattern is of importance for mastering the engine operation featuring uncontrolled flow separation inside the nozzle, appearing during engine start-up and shut-down operation. As consequence of uncontrolled flow separation, lateral loads may be induced. The side-load character strongly depends on the nozzle design, and is a key feature for the nozzle’s mechanical structure layout. It is shown especially for the VULCAIN and VULCAIN 2 nozzle, how specific shock patterns evolve during transients, and how - by the nozzle design - undesired flow phenomena can be avoided. 相似文献
63.
64.
Ternary halides are potential materials for nonlinear optical applications in the mid infrared because of their transparency. We discuss physical, chemical and crystallographic aspects and develop a concept for preparing nonlinear optical halides. Based on the bond-charge model optical hyperpolarizabilities are calculated for more than one hundred A-X bonds where X = Cl, Br or I. The calculations are tested as far as possible by a comparison with experimental data. The tests show that the listed hyperpolarizabilities are a sound basis for the calculation of nonlinear optical susceptibilities in halides. A list of cations is given which form bonds with large hyperpolarizabilities and which show the tendency to form acentric structures. Phase diagrams of the two selected systems TII-AsI3 and TII-BiI3 are studied experimentally. Large single crystals of the new acentric compound Tl7Bi3I16 and of Tl3PbCl5 are prepared. In both crystals twinning prevents an effective SHG effect. 相似文献
65.
O. Andersen R. Bauer G.B. Hagemann M.L. Halbert B. Herskind M. Neiman H. Oeschler H. Ryde 《Nuclear Physics A》1978,295(1):163-188
Reactions between 18O and 16O ions, with energies well above the Coulomb barrier, and 148, 150Nd target nuclei were used to study the cascades of γ-rays in the residual nuclei 161, 162Er. A multi-counter setup was used in which the γ-rays were detected by a Ge(Li) counter coupled in coincidence with up to 9 NaI(Tl) counters. The γ-multiplicity has been studied for γ-rays cascading through states above and along the yrast line. Higher moments of the multiplicity distributions (shape parameters) were deduced from the data. These moments allow the construction of the spin distribution for the entry states. The difference between these spin distributions from reactions induced by 16O and 18O ions was studied. Also the fusion cross section was measured for the two systems as a function of bombarding energy and compared to the multiplicity results at two different excitation energies (Ex = 49.5 and 56.2 MeV). A subtraction technique has been applied in the data analysis with the intention to study the decay of a selected part of the high-spin region, and the results show besides the 4n channel an unexpected large contribution of the 5n channel from this region. The sidefeeding patterns of the multiplicity distributions are extracted and show a significant difference for the 16O and 18O induced reactions, especially at the lowest bombarding energies. The results are compared with statistical model calculations. 相似文献
66.
R. A. Bark H. Carlsson S. J. Freeman G. B. Hagemann F. Ingebretsen H. J. Jensen T. L nnroth M. J. Piiparinen I. Ragnarsson H. Ryde H. Schnack-Petersen P. B. Semmes P. O. Tj m 《Nuclear Physics A》1998,630(3-4):603-630
Six rotational bands in the odd-odd nucleus 174Ta have been populated with the 160Gd(19F,5n) reaction. High-spin states were identified using the NORDBALL array. Both signatures of the doubly decoupled π1/2− [541] ν1/2− [521] band and semi-decoupled π1/2− [541] ν7/2− [633] band are observed, in addition to the high-K couplings of the π9/2− [514] ν7/2+ [633], π9/2− [514] ν5/2− [512], π7/2+ [404] ν7/2+ [633], and π5/2+ [402] ν5/2− [512] configurations. The signature splitting of the π1/2− [541] ν7/2+ [633] band is inverted from the expected splitting, and this is interpreted as being due to a residual proton-neutron interaction. It is shown empirically that this interaction, together with deformation changes, can account for the increased crossing frequency associated with the alignment of i13/2 neutrons in the π1/2− [541] bands of odd-Z nuclei. 相似文献
67.
G. Schönwaßer H. Hübel G.B. Hagemann J. Domscheit A. Görgen B. Herskind G. Sletten J.N. Wilson D.R. Napoli C. Rossi-Alvarez D. Bazzacco R. Bengtsson H. Ryde P.O. Tjøm S.W. Ødegård 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):291-296
Lifetimes of states in the yrast superdeformed bands of 163Lu and 164Lu were determined in a Doppler-shift attenuation-method experiment. From fractional Doppler shifts and line shapes, average
transition quadrupole moments, Q
t = 8.2-0.6
+1.0 b and 7.1-0.6
+0.5 b, were deduced for one of the bands in 163Lu and 164Lu, respectively. These values are much larger than the quadrupole moment of the normal-deformed yrast band in 163Yb, Q
t = 4.9-0.4
+1.3 b, that was also determined in this experiment. Comparison to cranking calculations indicates that both superdeformed bands
correspond to a local potential energy minimum with a pronounced triaxiality, γ∼ 20°.
Received: 8 November 2001 / Accepted: 9 January 2002 相似文献
68.
J.C. Bacelar M. Diebel C. Ellegaard J.D. Garrett G.B. Hagemann B. Herskind A. Holm C.-X. Yang J.-Y. Zhang P.O. Tjøm J.C. Lisle 《Nuclear Physics A》1985,442(3):509-546
The decay schemes of 167,168,169Yb are established to the largest angular momenta yet known in stably-deformed rare-earth nuclei using the 124Sn(48Ca,3–5n) reaction. The systematics of the resulting spectrum of single-neutron states in these and neighbouring Yb isotopes at large and small angular momenta are discussed with regard to that expected in the presence and absence of static neutron-pair correlations. This comparison, together with cranking-model and “gauge-space” analyses, provides evidence for the effective disappearance of static neutron-pair correlations for the odd-N isotopes at ?ω ? 0.38 MeV. A composite empirical spectrum of single-neutron states is constructed for the “unpaired” regime and is compared with cranking calculations. 相似文献
69.
70.
Martin Mohnhaupt Hans Hagemann Jean-Pascal Perler Hans Bill John Boukouvalas Jean-Claude Rossier Charles W. Jefford 《Helvetica chimica acta》1988,71(5):992-999
The vibrational spectra of some 1,2,4-trioxanes present two characteristic bands at 790 and 880 cm?1. On the basis of 18O-isotopic substitution and comparison with analogous compounds, these bands have been assigned to coupled C? O and O? O stretching modes of the C? O? O element. 相似文献