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排序方式: 共有2510条查询结果,搜索用时 15 毫秒
1.
A loop algebra is constructed, whose subalgebra is first used to present a Lax pair. By making use of the Tu scheme by Tu Guizhang, a generalized (2 + 1)-dimensional KN hierarchy is worked out. Further, based on the associated relations between the subalgebras in the above loop algebra, an extending integrable model of the generalized (2 + 1)-dimensional KN hierarchy as above is produced.  相似文献   
2.
《Tetrahedron: Asymmetry》2006,17(13):1969-1974
The preparation of new enantiopure cyclic nitrones based on the 1-oxy-2,3-dihydro-imidazol-4-one ring is described. The addition of arylmagnesium or alkynylzinc reagents to these nitrones can be achieved with total enantio- and diastereoselectivity, leading to α,α-disubstituted amino-acid precursors.  相似文献   
3.
In two-dimensional massless lattice QCD we construct the equation of motion for a gauge invariant meson operator with a quark-antiquark pair connected by the path-ordered products of link variables. Using the large-N factorization property the meson wave equation is derived ain a nearly identical form to the 't Hooft equation.  相似文献   
4.
《Fluid Phase Equilibria》1986,26(2):165-179
Occhiogrosso, R.N., Igel, J.T. and McHugh, M.A., 1986. Phase behavior of carbon dioxide-aromatic hydrocarbon mixtures. Fluid Phase Equilibria, 26: 165–179.Vapor-liquid-equilibria experiments are conducted at 299.25, 305.65, 316.25, 338.35, 363.15, and 383.15 K and for pressures up to 175 bar for the CO2-isopropyl benzene (cumene) system. Pressure-composition information is obtained. The resulting experimental data are modeled using the Peng-Robinson equation-of-state. Two temperature-independent model parameters, δij, which accounts for molecular interactions between CO2 and cumene, and ηij, which accounts for the size difference between CO2 and cumene, are used to obtain good agreement between calculated and experimental data.The results for the CO2-cumene system are compared to the CO2-toluene and CO2-m-xylene systems which are available in the literature. The CO2-toluene and CO2-m-xylene systems can be modeled using the same δij and ηij values used for the CO2-cumene system.  相似文献   
5.
Fatty acids, which are enriched in vegetable oil, have attracted much attention in low-rank coal flotation because of their unique chemical structure. In this study, density functional theory calculations, molecular dynamics simulations, and atomic force microscopy were employed to investigate the adsorption structure and forces between collectors and hydrophilic surfaces. The results show that fatty acids can be easily adsorbed onto surfaces through hydrogen bonds, and can cover the oxygen sites. The existence of hydration film on hydrophilic surfaces prevented nonpolar molecules from being able to adsorb, while polar fatty acids could adsorb and expel water molecules. The adhesion force between the RCOOH-terminated probe and the surface appeared in the retraction process, which differed significantly from that of the RCH3-terminated probe, indicating that polar fatty acids are more suitable as flotation collectors for low-rank coal than nonpolar hydrocarbon oil. The simulation and AFM test revealed the mechanisms of polar fatty acids, and can provide guidance for low-rank coal flotation applications.  相似文献   
6.
《Optics Communications》1986,59(1):23-26
We report a complete and exact analysis of the steady-state physical properties characterising a single radiating atom in a cavity of arbitrary Q. Solutions are in terms of multitime correlation functions and no approximation is made in terms of Q, temperature, or strength of field-atom coupling g. Results are import also to fundamental concepts of statistical mechanics such as adiabatic following and Markov approximations.  相似文献   
7.
8.
《Journal of luminescence》1986,34(6):295-305
Optical studies of Bridgman grown LiYF4 crystals weakly doped with Nd3+ have been made in the vicinity of the 4I9/24G5/2 transition. By selective excitation with a narrow pulsed laser or with a CW monomode laser, excitation spectra and dynamical characteristics of infrared and ultraviolet (up-converted) fluorescences produced by satellites associated with Nd3+ pairs have been obtained. From the results, an assignment of the satellites to the various classes of pairs has been possible. The existence of a short range interaction, probably superexchange, has been proved which confirms previous observations in another fluoride compound, LaF3.  相似文献   
9.
《Wave Motion》1986,8(4):329-339
Various evolution equations for long interfacial waves with shear flow are derived with the assumptions that: (1) the wavelength of the interfacial waves is much larger than the total depth of the fluids, and (2) that the spanwise dependence is much weaker than the streamwise dependence. A particular case of interest occurs when the interfacial waves are at or near direct resonance. In this case the Boussinesq equation replaces the Korteweg-de Vries equation. Various special solutions in two dimensions are discussed.  相似文献   
10.
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