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101.
The time-dependent turbulent Navier–Stokes equations are solved numerically by a finite element method with an algebraic eddy viscosity model (Baldwin–Lomax formulation) for oscillating turbulent channel flows. The method of averaging is used to analyse the resulting periodic motion of the fluid. Numerical results are obtained for various Strouhal numbers and relative amplitudes. A comparison is made between the numerical and published experimental results. It appears that for low relative amplitudes in a certain range of frequencies the agreement is satisfactory. 相似文献
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Richard F. Smith Christopher J. Aquino Laurie A. Olson Julienne M. Galante Stephen C. Liptak 《Tetrahedron letters》1985,26(46):5663-5666
2-Benzyl-3-imino-1-phenylpyrazolidine (5a) and 2-allyl-3-imino-1-phenylpyrazolidine (5b) are obtained by the base-promoted rearrangement of the title compounds (4a and 4b). 相似文献
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Thermotransmission measurements have been made of the M2,3 edge in Ni using synchrotron radiation. The edge shows considerable temperature dependence, apparently that of a gap shift. A fit of one spin-orbit component of the thermotransmission spectrum with the Fano line shape indicates that both Fano parameters, ? and q, are temperature dependent. The fit indicates a temperature dependence of at least two microscopic parameters. 相似文献
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We have measured the optical absorption below the fundamental threshold, the normal-incidence reflectivity between 1.5 and 30 eV and the X-ray photoemission spectra of NiPS3. Shake-up satellites present at the Ni 2p and 3p core levels are strong evidence for the ionicity of the NiS bonds. We have also derived a qualitative molecular orbital model of NiPS3 in which the trigonal crystal field splits the P and S 3pxpy-3pa states, and strong covalent hybridization between P and S pxpy orbitals leads to covalent electronic bonding. Ni is envisaged as a divalent ion which plays little role in the electronic bonding and its 3d levels are localized, lying near the top both of the valence states. This model accounts well for both the valence band XPS data and the low energy optical transitions. Our model should represent, at the center of the Brillouin zone but not at the boundaries, the energy level sequence in NiPS3 and other related MPX3 layer-type compounds where M Co2+, Mn2+, Fe2+, Zn2+ and X is sulfur or selenium.The XPS spectra and optical properties of NiPS3 have been obtained and interpreted on a qualitative molecular orbital model in which the Ni is a divalent positive ion which plays little role in the bonding. Evidence for such ionicity appears in the optical properties and XPS satellite structures, as well as in the magnetic properties. The model should represent qualitatively the band structure at the center of the Brillouin zone, but not at the boundaries. It should also be valid for other compounds similar to NiPS3, i.e. those with other metals in place of Ni and those with Se in place of S. 相似文献