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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.
The Boussinesq system is investigated by using the tanh method and the sine–cosine method. A variety of exact travelling wave solutions with compact and noncompact structures are formally obtained. The study shows that each method gives distinct solutions and one method complements the other.  相似文献   
4.
Heavy metal cations Cd2+, Pb2+, and Hg2+ were added to substitute for Ca2+ in culture media to study their effect on the relationship between CaM and the proliferation of cultured rabbit aortic smooth muscle cells (ASMC). It was found that all the heavy metal cations studied stimulated the proliferation of ASMC in varying degrees, increased the CaM content in cells at late G1 stage and decreased the activity of cAMP PDE. These results suggest that the adverse effect of heavy metals may be related to the pathogenesis of atherosclerosis and hypertensive disease.  相似文献   
5.
A novel non-chromatographic approach for direct speciation of mercury, based on the selective retention inorganic mercury and methylmercury on the inner wall of a knotted reactor by using ammonium diethyl dithiophosphate and dithizone as complexing agents respectively, was developed for flow injection on-line sorption preconcentration coupled with chemical vapor generation non-dispersive atomic fluorescence spectrometry. With the sample pH kept at 2.0, the preconcentration of inorganic mercury on the inner walls of the knotted reactor was carried out based on the exclusive retention of Hg–DDP complex in the presence of methylmercury via on-line merging the sample solution with ammonium diethyl dithiophosphate solution, and selective preconcentration methylmercury was achieved with dithizone instead of ammonium diethyl dithiophosphate. A 15% (v/v) HCl was introduced to elute the retained mercury species and merge with KBH4 solution for atomic fluorescence spectrometry detection. Under the optimal experimental conditions, the sample throughputs of inorganic mercury and methylmercury were 30 and 20 h 1 with the enhancement factors of 13 and 24. The detection limits were found to be 3.6 ng l 1 for Hg2+ and 2.0 ng l 1 for CH3Hg+. The precisions (RSD) for the 11 replicate measurements of each 0.2 μg l 1 of Hg2+ and CH3Hg+ were 2.2% and 2.8%, respectively. The developed method was validated by the analysis of certified reference materials (simulated natural water, rice flour and pork) and by recovery measurements on spiked samples, and was applied to the determination of inorganic mercury and methylmercury in biological and environmental water samples.  相似文献   
6.
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   
7.
《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   
8.
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   
9.
《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   
10.
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