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21.
Ravi P. Agarwal Donal O’Regan Svatoslav Staněk 《Central European Journal of Mathematics》2009,7(4):694-716
The paper is concerned with existence results for positive solutions and maximal positive solutions of singular mixed boundary
value problems. Nonlinearities h(t;x;y) in differential equations admit a time singularity at t=0 and/or at t=T and a strong singularity at x=0. 相似文献
22.
The general method for design of the pulse electromagnet with the rectangular coil is given in this paper. By means of this method the external magnetic field for the plasma cluster acceleration in the rail accelerator has been realized. The experimentally obtained dependences of the plasma cluster path and velocity on the external magnetic field are included. 相似文献
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We have measured the maximum field for which vortices are completely expelled from a thin-film superconducting strip. Niobium strips of width W were field cooled and imaged with a scanning Hall-probe microscope. Below a critical field B(m) approximately Phi(0)/W(2) all flux was expelled; above this field vortices were observed with a density increasing approximately linearly with field. The small value of the critical field, which is orders of magnitude less than in the bulk, implies that superconducting devices should be designed with narrow wires to eliminate the generation of noise from vortex motion. 相似文献
25.
Kuijpers BH Groothuys S Keereweer AB Quaedflieg PJ Blaauw RH van Delft FL Rutjes FP 《Organic letters》2004,6(18):3123-3126
[structure: see text] An expedient, high-yielding synthesis of two types of triazole-linked glycopeptides is described. These novel and stable glycopeptide mimics were prepared via Cu(I)-catalyzed [3 + 2] cycloaddition of either azide-functionalized glycosides and acetylenic amino acids or acetylenic glycosides and azide-containing amino acids. 相似文献
26.
Chong DP van Lenthe E Van Gisbergen S Baerends EJ 《Journal of computational chemistry》2004,25(8):1030-1036
Even-tempered Slater-type orbital basis sets were developed in 1973, based on total atomic energy optimization. Here, we revisit ET STOs and propose new sets based on past experience and recent computational studies. From preliminary atomic and molecular tests, these sets are shown to be very well balanced and to perform, at lower cost, almost as well as a very large (close to complete) basis set. 相似文献
27.
Hadzibabic Z Gupta S Stan CA Schunck CH Zwierlein MW Dieckmann K Ketterle W 《Physical review letters》2003,91(16):160401
We have produced a quantum degenerate 6Li Fermi gas with up to 7 x 10(7) atoms, an improvement by a factor of 50 over all previous experiments with degenerate Fermi gases. This was achieved by sympathetic cooling with bosonic 23Na in the F=2, upper hyperfine ground state. We have also achieved Bose-Einstein condensation of F=2 sodium atoms by direct evaporation. 相似文献
28.
R. Stanoeva V. Bradnova S. Vokál P. I. Zarubin I. G. Zarubina N. A. Kachalova A. D. Kovalenko A. I. Malakhov G. I. Orlova N. G. Peresadko P. A. Rukoyatkin V. V. Rusakova E. Stan M. Haiduc S. P. Kharlamov I. Tsakov T. V. Shchedrina 《Physics of Atomic Nuclei》2007,70(7):1216-1221
The results obtained by studying the charge topology of fragments produced in the peripheral dissociation of relativistic 8B nuclei in emulsion are presented. Fifty-five events of the peripheral dissociation of a 8B nucleus in events where there was no production of target-nucleus fragments and mesons (“white stars”) were selected. A leading contribution of the 8B → 7Be + p mode, which has the lowest energy threshold, was revealed on the basis of these events. Information about the branching ratios for dissociation modes characterized by a higher multiplicity was obtained. The dissociation of the 7Be core in 8B bears resemblance to the dissociation of a free 7Be nucleus. The transverse-momentum distributions of fragments originating from the 8B → 7Be + p dissociation mode were obtained. For these distributions, a small mean value of 〈P*T〉 = 52 ± 5 MeV/c in the c.m. frame suggests a low binding energy of the outer proton in the 8B nucleus. An indication of a strong azimuthal correlation of the fragments 7Be and p was found. 相似文献
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