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81.
Anders Bjarklev J rn Hedegaard Povlsen Karsten Rottwitt Ole Lumholt Thomas Rasmussen 《Fiber and Integrated Optics》1991,10(3):215-223
Erbium-doped fiber amplifiers (EDFAs) in eight different system configurations are investigated, using a full-scale model, and the midline placement of the amplifier is shown to be optimal. A distributed amplifier compared to the remote pumping scheme shows no system improvement. Use of a booster (next to the transmitter), a midline remote-pumped amplifier, and a preamplifier (next to the receiver) allows up to 180 km of extra transmission fiber to be added. 相似文献
82.
Summary A summary is given of some recent attempts to relate the results of the kinetic theory of rigid and flexible macromolecules to continuum mechanics results.With 1 table 相似文献
83.
84.
Alexander Berkovich S. Ole Warnaar 《Transactions of the American Mathematical Society》2005,357(6):2291-2351
Several new transformations for -binomial coefficients are found, which have the special feature that the kernel is a polynomial with nonnegative coefficients. By studying the group-like properties of these positivity preserving transformations, as well as their connection with the Bailey lemma, many new summation and transformation formulas for basic hypergeometric series are found. The new -binomial transformations are also applied to obtain multisum Rogers-Ramanujan identities, to find new representations for the Rogers-Szegö polynomials, and to make some progress on Bressoud's generalized Borwein conjecture. For the original Borwein conjecture we formulate a refinement based on new triple sum representations of the Borwein polynomials.
85.
Using the theory of Macdonald polynomials, a number of q-integrals of Selberg type are proved.
2000 Mathematics Subject Classification: Primary—33D05, 33D52, 33D60 相似文献
86.
We study the existence of solutions to the orthogonal dynamics equation, which arises in the Mori-Zwanzig formalism in irreversible
statistical mechanics. This equation generates the random noise associated with a reduction in the number of variables. IfL is the Liouvillian, or Lie derivative associated with a Hamiltonian system, andP an orthogonal projection onto a closed subspace ofL
2, then the orthogonal dynamics is generated by the operator (I −P)L. We prove the existence of classical solutions for the case whereP has finite-dimensional range. In the general case, we prove the existence of weak solutions. 相似文献
87.
The paper describes an interactice, computer based procedure for solving the variant of the vehicle loading problem encountered when loading containers and pallets into an aircraft. The procedure is heuristic and practical oriented; it is presently being implemented by Scandinavian Airlines. 相似文献
88.
The spin polarization of the conduction electrons of a doped semiconductor (e.g. EuO + x%Gd) is calculated using a moment method together with an alloy analogy. It is shown to be caused by a complicated temperature- and carrier concentration-dependence of the quasiparticle spectrum of the s-f model. Obtained polarization agrees very well with recent photoemission experimental data. 相似文献
89.
The influence of surface polaritons (SPs), excited on the external (fast mode) and internal (slow mode) surfaces of a gold film, on the tunneling current of a STM is investigated. The role of the surface polaritons is directly demonstrated by the angular excitation spectra of the induced tunneling current. Possible mechanisms which might give rise to the SP induced change in the tunneling current are discussed. An electromagnetic field of SPs within a tunneling gap is estimated to be surface enhanced in order to explain the value of the induced tunneling current. Images of the polariton induced signal distribution over the sample surface taken by means of different SP modes are compared in order to obtain information on the structure of the internal surface of the film. 相似文献
90.
The local approach for the intraatomic correlation is applied to study the ground state phase diagram of the extended Hubbard model with a half-filled band. The long-range orders are not destroyed by the correlation effect in the limit of weak interaction, though the values of the order parameters are reduced from those of the Hartree-Fock approximation, especially for the antiferromagnetic-state. We find that the antiferromagnetic-charge order phase boundary is only slightly shifted towards the charge ordered state, while the phase boundary between the singlet superconducting and the charge ordered phases remains the same as that derived from the Hartree-Fock approximation. 相似文献