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51.
Niedermaier O Scheit H Bildstein V Boie H Fitting J von Hahn R Köck F Lauer M Pal UK Podlech H Repnow R Schwalm D Alvarez C Ames F Bollen G Emhofer S Habs D Kester O Lutter R Rudolph K Pasini M Thirolf PG Wolf BH Eberth J Gersch G Hess H Reiter P Thelen O Warr N Weisshaar D Aksouh F Van den Bergh P Van Duppen P Huyse M Ivanov O Mayet P Van de Walle J Aystö J Butler PA Cederkäll J Delahaye P Fynbo HO Fraile LM Forstner O Franchoo S Köster U Nilsson T Oinonen M Sieber T Wenander F Pantea M 《Physical review letters》2005,94(17):172501
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient gamma spectrometer MINIBALL. Using 30Mg ions accelerated to an energy of 2.25 MeV/u together with a thin (nat)Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation gamma-ray yields the B(E2;0(+)gs-->2(+)1) value of 30Mg was determined to be 241(31)e2 fm4. Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope 30Mg resides outside the "island of inversion." 相似文献
52.
Döhrmann S Hägele D Rudolph J Bichler M Schuh D Oestreich M 《Physical review letters》2004,93(14):147405
A strong anisotropy of electron spin decoherence is observed in GaAs/(AlGa)As quantum wells grown on a (110) oriented substrate. The spin lifetime of spins perpendicular to the growth direction is about one order of magnitude shorter compared to spins along [110]. The spin lifetimes of both spin orientations decrease monotonically above temperatures of 80 and 120 K, respectively. The decrease is very surprising for spins along the [110] direction and cannot be explained by the usual Dyakonov-Perel dephasing mechanism. A novel spin dephasing mechanism is put forward that is based on scattering of electrons between different quantum well subbands. 相似文献
53.
The Cronin effect that refers to the enhancement of hadron spectra at intermediate p(T) with increasing A in pA collisions is traditionally explained in terms of the broadening of the parton transverse momentum in the initial state. We show that recent data on the nuclear modification factor at eta=0 for d+Au collisions can be understood in terms of the recombination of soft and shower partons in the final state. It is the centrality dependence of the soft parton density that leads to the Cronin effect. 相似文献
54.
Synchronously pumped Raman oscillators allow for an efficient frequency conversion of pump pulses whose power is well below the threshold for extracavity stimulated Raman scattering (SRS). Numerical simulations show that the cavity mismatch of pump laser and Raman oscillator is critical for maximum conversion efficiency and minimum pulse duration for transient and stationary SRS. At a certain mismatch the simulations predict a quasi-cw Raman oscillator output even at moderate cavity quality factors. Optimum operation conditions are discussed for pump pulse trains of finite lengths. The results of the numerical calculations are in qualitative agreement with a simple phenomenological model. PACS 42.55.Ye; 42.65.Dr; 42.55.Lt 相似文献
55.
Vázquez J Demaison J López-González JJ Boggs JE Rudolph HD 《Journal of Molecular Spectroscopy》2001,207(2):224-237
The equilibrium structure of 1,2,5-oxadiazole has been calculated ab initio at the CCSD(T) level using a polarized valence quadruple zeta basis set. The harmonic force field has also been calculated at the MP2/cc-pVTZ, B3LYP/6-311++G(3df, 2pd), and B3LYP/cc-pVQZ levels. These force fields have been subsequently scaled and further refined by fitting them to the experimental values of the vibrational fundamentals of three isotopomers and the centrifugal distortion constants of the parent molecule. The specific refinement of those scaled force constants particularly sensitive to the experimental data set was decisive for obtaining a more reliable harmonic potential. The resulting force fields are presented and used, together with the ground state rotational constants, to calculate an r(z) structure. The experimental r(0), r(s), and r(m) structures have also been determined. The different results have been compared and it is concluded that the ab initio structure is a good approximation of the equilibrium structure. It is also shown that the magnetic correction is not negligible, particularly for the inertial defect. Another interesting conclusion is that the anharmonicity of the C-H stretching might be unusually small. Copyright 2001 Academic Press. 相似文献
56.
S. Pietri P. H. Rega Zs. Podolyák A. Jungclaus M. Pfützner D. Rudolph A. B. Garnsworthy S. J. Steer R. Hoischen M. Górska J. Gerl H. J. Wollersheim I. Kojouharov H. Schaffner J. Grębosz F. Becker P. Bednarczyk L. Caceres P. Doornenbal H. Geissel A. Kelic N. Kurz F. Montes W. Prokopowicz T. Saito S. Tashenov E. Werner-Malento W. Gelletly 《The European physical journal. Special topics》2007,150(1):319-320
The RISING (Rare ISotope INvestigations at GSI) project constitutes a major
pan-european initiative to study nuclear structure in exotic nuclei.
A brief outline of the technical details specific to studies of isomeric decays
following relativistic projectile fragmentation reactions is presented. 相似文献
57.
Novel polyesteramide-based di- and triblock copolymers: From thermo-mechanical properties to hydrolytic degradation 总被引:1,自引:0,他引:1
Gaëlle Deshayes Cécile Delcourt Ingrid Verbruggen Lise Trouillet-Fonti Franck Touraud Etienne Fleury Philippe Degée Mathias Destarac Rudolph Willem Philippe Dubois 《European Polymer Journal》2011,(1):98-110
Two types of biodegradable poly(ε-caprolactone (CLo))-co-poly(ε-caprolactam (CLa)) copolymers were prepared by catalyzed hydrolytic ring-opening polymerization. For the first type of materials, the respective cyclic comonomers were added simultaneously in the reaction medium leading to the formation of copolymers having a random distribution of co-units within the polyesteramide sequence, as evidenced by 1H and 13C NMR. For the second type of copolymers, the cyclic comonomers were added sequentially in the reaction medium yielding diblock polyesteramides, again evidenced by NMR. The thermal and thermo-mechanical properties of the copolymers were investigated by DSC and DMA and correlated with the copolymer topology and composition. The copolymers were characterized by a storage modulus and α transition temperature intermediate to the modulus and Tg of the corresponding homopolymers. The chemical composition and molecular weight of the copolymers proved to have only a limited effect on the thermo-mechanical properties of the materials. The hydrolytic degradation of random copolymers was studied in a phosphate buffer at 60 °C and discussed in terms of chemical composition and molecular weight of the copolymers. 相似文献
58.
59.
60.
T. Schröder W. Rudolph S. V. Govorkov I. L. Shumay 《Applied Physics A: Materials Science & Processing》1990,51(1):49-51
Primary steps of melting (disordering) of GaAs surface layers after femtosecond pulse excitation have been measured through second-harmonic generation in reflection. A numerical fit of the experimental data yield a characteristic time delay between excitation and lattice melting of about 75 fs. 相似文献