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21.
C. Donzaud S. Czajkowski P. Armbruster M. Bernas C. Böckstiegel P. Dessagne H. Geissel E. Hanelt A. Heinz C. Kozhuharov C. Miehé G. Münzenberg M. Pfützner W. Schwab C. Stéphan K. Sümmerer L. Tassan-Got B. Voss 《The European Physical Journal A - Hadrons and Nuclei》1998,1(4):407-426
Projectile fission of 750 AMeV 238U-ions interacting with a Pb target was studied by means of the spectrometer FRS, GSI-Darmstadt. One of the two fission fragments
was detected with a transmission of few percent and identified in mass and charge. Low-energy fission (E* < 25 MeV) events were selected by their magnetic rigidity. Whereas the production of asymmetric fission events is dominated
by the GDR excitation, very asymmetric fission and symmetric fission take place after a GQR or DGDR excitation or after a
nuclear interaction. Cross sections of more than 250 isotopes were measured. Isotopic distributions of low-energy fission
were reconstructed for elements from Se to Te. The fission modes SI, SII and SL were clearly shown in these distributions
and in the mass and TKE distributions. Charge polarization and mass dispersion were deduced for each fission mode. Finally,
the characteristics of the low-energy fission process explain the production rates of neutron-rich species.
Received: 14 July 1997 / Revised version: 6 October 1997 相似文献
22.
23.
Daniel Král’ Jan Kratochvíl Andrzej Proskurowski Heinz-Jürgen Voss 《Discrete Applied Mathematics》2006,154(4):660-672
A mixed hypergraph is a triple (V,C,D) where V is its vertex set and C and D are families of subsets of V, called C-edges and D-edges, respectively. For a proper coloring, we require that each C-edge contains two vertices with the same color and each D-edge contains two vertices with different colors. The feasible set of a mixed hypergraph is the set of all k's for which there exists a proper coloring using exactly k colors. A hypergraph is a hypertree if there exists a tree such that the edges of the hypergraph induce connected subgraphs of the tree.We prove that feasible sets of mixed hypertrees are gap-free, i.e., intervals of integers, and we show that this is not true for precolored mixed hypertrees. The problem to decide whether a mixed hypertree can be colored by k colors is NP-complete in general; we investigate complexity of various restrictions of this problem and we characterize their complexity in most of the cases. 相似文献
24.
Mario Piris 《Journal of mathematical chemistry》1998,23(3-4):399-404
The first derivatives of the total energy with respect to nuclear displacement have been calculated in the framework of the
Improved Bardeen–Cooper–Schrieffer (IBCS) method. It permits the quick determination of the stationary points.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
25.
Mario Landucci 《Annali di Matematica Pura ed Applicata》1989,155(1):193-203
Sunto In questo lavoro si studia il problema dell'existenza o meno di mappe olomorfe proprie, F: (p,q) (pq) dove (,) Cn sono domini limitati, pseudoconvessi, non lisci, di Reinhardt con centro di simmetria sulla frontiera (per la definizione v. (2), introduzione). In caso affermativo si fornisee esplicitamente l'espressione di tali mappe (v, teoremi I e II nell'introduzione).
The author, during the redaction of this paper, was supported by MPI (40% and 60%) funds. 相似文献
The author, during the redaction of this paper, was supported by MPI (40% and 60%) funds. 相似文献
26.
We characterize the existence of blocking sets in a particular class of S (3,4,v) and we give a construction to obtain S(3,4,2v) having blocking sets.Lavoro eseguito nell'ambito del GNSAGA e con contributo del M.P.I. 相似文献
27.
Summary In this paper we study the Dirichlet problem, for second order, linear elliptic partial differential equations with discontinuous coefficients in unbounded domains. We obtain some results about existence and uniqueness of the solution in W2().
Lavoro eseguito nell'ambito del G.N.A.F.A. del C.N.R. 相似文献
Lavoro eseguito nell'ambito del G.N.A.F.A. del C.N.R. 相似文献
28.
Franco Piacenti Mario Bianchi Piero Frediani Ugo Matteoli 《Journal of organometallic chemistry》1975,87(3):C54-C55
Both normal and secondary alkylcobalt carbonyls are shown not to undergo isomerization under catalytic “oxo” conditions, and the relevance of this obervation for the mechanism of the “oxo” reaction is discussed. 相似文献
29.
Alkyl thione (2) and dithiobenzoates (3) as well as their aryl substituted derivatives 4 and 5 may be converted into radical anions by in situ electroreduction.—The EPR spectra of 2–5 are measured. Conclusions about the spin density distribution within the aromatic ring and the functional group are drawn from the hyperfine structure coupling constants, g-values and polarographic half wave potentials, whereby the effect of ortho substituents (twisting of the two halves of the molecule) is especially considered.—The results agree sufficiently with MO calculations of the McLachlan type.Inspection of the alkyl coupling constants shows that the alkyl groups exhibit conformations of minimum steric hindrance of the thiocarbonyl group. 相似文献
30.
JPC – Journal of Planar Chromatography – Modern TLC - A new simple, rapid, and selective high-performance thin-layer chromatographic (HPTLC) method with metronidazole as the internal... 相似文献