排序方式: 共有75条查询结果,搜索用时 500 毫秒
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Polubarinova-Kochina's analytical differential equation methodis used to determine the pseudo-steady-state solution to problemsinvolving the freezing (solidification) of wedges of liquidwhich are initially at their fusion temperature. In particular,we consider four distinct problems for wedges which are: freezingwith the same constant boundary temperature, freezing with thesame constant boundary heat fluxes, freezing with distinct constantboundary temperatures and freezing with distinct constant fluxesat the boundaries. For the last two problems, a Heun's differentialequation with an unknown singularity is derived, which in bothcases admits a particularly elegant simple solution for thespecial case when the wedge angle is . The moving boundariesobtained are shown pictorially. 相似文献
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Alves GA Amato S Anjos JC Appel JA Astorga J Bernard T Bracker SB Cremaldi LM Darling CL Dixon RL Errede D Gay C Green DR Jedicke R Karchin PE Kwan S Lueking LJ de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A Passmore D Rafatian A dos Reis AC Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wallace A Wu Z 《Physical review letters》1994,72(6):812-815
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J. M. Wesselinowa 《Zeitschrift für Physik B Condensed Matter》1987,69(2-3):279-281
A theoretical study of spin-phonon interaction in a Heisenberg ferromagnet is made on the basis of a Green function technique. We have calculated below and aboveT
c
the renormalized phonon energy and the phonon damping for the first time beyond the RPA. The obtained temperature and magnetic field dependence of the phonon relaxation time is in good agreement with the experimental data. 相似文献
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J. M. Wesselinowa 《Zeitschrift für Physik B Condensed Matter》1987,68(1):57-62
A Green function technique is used to study the effects of spin-phonon interactions in a Heisenberg ferromagnet. The transverse and longitudinal damping of the spin-wave energy for two different spin-phonon interaction mechanisms are evaluated for the first time beyond the RPA. The results are valid below and aboveT
c
. 相似文献
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Based on the spin-phonon model we analyze the influence of surface and size effects on the phonon properties of ferromagnetic nanoparticles. A Green's function technique in real space enables us to calculate the renormalized phonon energy and its damping depending on the temperature and the anharmonic spin-phonon interaction constants. With decreasing particle size the phonon energy can decrease or increase for different surface spin-phonon interaction constants, whereas the damping increases always. The influence of an external magnetic field is discussed, too. The theoretical results are in reasonable accordance to experimental data. 相似文献
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