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991.
992.
993.
Misbahul Ain Khan Antonio Carlos Carreira Freitas 《Journal of heterocyclic chemistry》1983,20(2):277-279
A number of 1, 5′-bipyrazoles were obtained from the condensation of pyrazol-5-ylhydrazine and 1, 3-dicarbonyl compounds. Electrophilic substitution reactions of these 1, 5′-bipyrazoles occur at the four position of the pyrazole ring. 相似文献
994.
Angelo Crugnola Antonio Longo Ferruccio Casabuona Paolo Lombardi 《Tetrahedron letters》1981,22(41):4141-4144
The synthesis of chiral “4,7-lactam“ has been accomplished starting from natural 6-aminopenicillanic acid. 相似文献
995.
996.
Summary When two immiscible fluids in a porous medium are in contact with one another, an interface is formed and the movement of
the fluids results in a free boundary problem for determining the location of the interface along with the pressure distribution
throughout the medium. The pressure satisfies a nonlinear parabolic partial differential equation on each side of the interface
while the pressure and the volumetric velocity are continuous across the interface. The movement of the interface is related
to the pressure through Darcy’s law. Two kinds of boundary conditions are considered. In Part I the pressure is prescribed
on the known boundary. A weak formulation of the classical problem is obtained and the existence of a weak solution is demonstrated
as a limit of a sequence of classical solutions to certain parabolic boundary value problems. In Part II the same analysis
is carried out when the flux is specified on the known boundary, employing special techniques to obtain the uniform parabolicity
of the sequence of approximating problems.
Entrata in Redazione il 29 novembre 1975.
This research was supported in part by the National Science Foundation, the Senior Fellowship Program of the North Atlantic
Treaty Organization, the Italian Consiglio Nazionale delle Ricerche, and the Texas Tech. University. 相似文献
997.
998.
Antonio Coniglio 《Physica A》1993,200(1-4):165-170
Recent work showing evidence for multiscaling in large two dimensional DLA clusters is reviewed. A connection between multiscaling and multifractality is also shown resulting in a weak localization of the growth sites (δ-sites) in shells around the cluster seed. 相似文献
999.
A convenient route to the daunomycinone precursor 18via a succession of Diels-Alder reactions from 2,7-dichloronaphthazarin (9) is described. In a similar manner, starting from 2,6-dichloronaphthazarin (19) compound 20, a regioisomer of 18,is synthesized. This methodology constitutes a regiospecific approach to (±)-daunomycinone and related anthracyclinones. 相似文献
1000.
Alberto Castellón Serrano Antonio Fernández López Amable García Martín Cándido Martín González 《manuscripta mathematica》1996,90(1):479-487
In this paper, we use the known classification of the finite capacity simple alternative pairs and the version of the Litoff
Theorem for Jordan pairs to describe all the strongly prime alternative pairs with nonzero socle. We study the inheritance
of some properties (primeness, nondegenerancy,…) when passing from the original alternative pair to the symmetrized pair.
Thus, we can apply Jordan theoretical results to the alternative case.
This work has been partially supported by 1) the “Plan Andaluz de Investigación y Desarrollo Tecnológico” with project no.
1027 and 2) the DGICYT with project no. PB93-0990 相似文献