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71.
Günter Sigl 《Pramana》2003,60(2):279-289
The highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the
most energetic processes in the universe. Their existence triggered a flurry of theoretical explanations ranging from conventional
shock acceleration to particle physics beyond the standard model (SM) and processes taking place at the earliest moments of
our universe. Furthermore, many new experimental activities promise a strong increase of statistics at the highest energies
and a combination with γ-ray and neutrino astrophysics will put strong constraints on these theoretical models. We give an
overview over this quickly evolving research field with focus on testing new particle physics. 相似文献
72.
S. Kotani 《Reports on Mathematical Physics》2007,59(3):305-316
M. G. Krein established a one-to-one correspondence between strings with regular left boundary and their spectral measures. In this note we treat strings with a certain class of singular left boundary and obtain a condition that the spectral measure grows polynomially. 相似文献
73.
Marcus Ritt Alysson M. Costa Sergio Mergen Viviane M. Orengo 《European Journal of Operational Research》2009
We introduce a problem called maximum common characters in blocks (MCCB), which arises in applications of approximate string comparison, particularly in the unification of possibly erroneous textual data coming from different sources. We show that this problem is NP-complete, but can nevertheless be solved satisfactorily using integer linear programming for instances of practical interest. Two integer linear formulations are proposed and compared in terms of their linear relaxations. We also compare the results of the approximate matching with other known measures such as the Levenshtein (edit) distance. 相似文献
74.
We present a set of formulas describing classical radiation of a rank-s tensor field from an accelerated pointlike source
in a flat space-time of an arbitrary even dimension d. These formulas allow straightforwardly and algorithmically evaluating
the total intensity and radiated momentum for any s and d by hand or using a computer. The practical application of the obtained
results is limited for s > 1 because the energy-momentum tensor for the pointlike source is not conserved. This usually means that contributions to the
radiation from tensions of the forces causing the acceleration of the radiation source cannot be neglected.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 156, No. 2, pp. 282–291, August, 2008. 相似文献
75.
In this paper we analyze from the mathematical point of view a model for small vertical vibrations of an elastic string with fixed ends and the density of the material being not constant. We employ techniques of functional analysis, mainly a theorem of compactness for the analysis of the approximation of Faedo-Galerkin method. We obtain strong global solutions with restrictions on the initial data u0 and u1, uniqueness of solutions and a rate decay estimate for the energy. 相似文献
76.
A new subgroup of3He rich solar flares is found on reanalysing the global data.3He/H ratio as a function of maximum proton flux at an energy of about 10 MeV shows a break-up of the data into two groups.
The first group follows the anticorrelation of3He/H ratio with the proton flux, as expected in the plasma process acceleration models. But the second group has a constant3He/H ratio as a function of maximum proton flux. This is not in conformity with the plasma process models. But this is expected
in models where the nuclear spallation reactions are responsible for the production of3He. It is also found that the same break-up into two distinct groups follows if one plots the location of the flares in the
solar disc. The first group is more or less confined to the west limb of the Sun, whereas the second group is more widely
spread out across the solar disk.
Visiting Professor, Tata Institute of Fundamental Research, Bombay, August–September, 1983. 相似文献
77.
78.
79.
S. Frste 《Annalen der Physik》1992,504(2):98-105
Conformal invariance conditions on a sigma model of the open bosonic string including the tachyon, the abelian gauge field an the first excited massive mode are calculated up to order a′. Inner symmetries are used to compute conformal invariance conditions from renormalization group beta functions. 相似文献
80.