a simple and efficient one-pot three-component synthesis of the biologically important spirooxindole-4h-pyrans was carried out by the reaction of isatin, activated methylene reagents, and 4-hydroxycoumarin in aqueous medium. sba-pr-nh2 was found to be an efficient heterogeneous nanoporous solid basic catalyst (pore size of 6 nm) which can be easily handled and removed from the reaction mixture ...

we wish to report a mild and efficient one-pot three-component reaction of an aryl aldehyde, malononitrile and barbituric acid or 4-hydroxycoumarinfor the synthesis ofpyrano[2,3-d]pyrimidine and dihydropyrano[c]chromene derivatives in the presence of iron ore pellet as a natural and reusable catalyst under heterogeneous and green conditions. the present methodology offers several advantages suc...

Submillimetre maps of NGC 891 have been obtained with the PRONAOS balloonborne telescope and with the ISOPHOT instrument on board the ISO satellite. In this article, we also gather data from IRAS and SCUBA to present the complete submillimetre spectrum of this nearby edge-on spiral galaxy. We derive submillimetre emission profiles along the major axis. The modified blackbody fits, assuming a si...

Abstract The hydromechanics of the fluidized bed processing medium is presented; conditions for its formation, stability, and limits existence are given. stochasticity a two-phase hydromechanical process in has been determined. boundary on surface spherical processed part vibrating machine reservoir considered. It was found that velocity granules during collision with part, addition to chaotic ...

We study the effect of homogenization on flame propagation in periodic excitable media, when the width of the flame is much smaller than the characteristic size of the heterogeneities.

The paper reviews single-neuron learning rules for minor component analysis and suggests a novel minor component learning rule. In this rule, the weight vector length is self-stabilizing, i.e., moving towards unit length in each learning step. In simulations with low- and medium-dimensional data, the performance of the novel learning rule is compared with previously suggested rules.

iii Symbols A constant I i intensity of ith component Mg.OEP magnesium octaethyl porphyrin Pt.OEP platinum octaethyl porphyrin P(S i), P(T i) singlet and triplet states of metalloporphyrin molecules R = S Doppler parameter, T i ith triplet state X(O 2) mole fraction of oxygen in surrounding medium τ i lifetime of ith component Superscript: * excited state of complex S with light