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The nonacidulated P fraction of partially acidulated phosphate rocks (PAPR) was obtained by extraction with alkaline ammonium citrate solution. Investigations on this unacidulated rock residues using standard analytical techniques and electronbeam microanalysis showed a surface “coating” with highly increased fluorine content surrounding the unreacted(More)
Khouribga phosphate rock was partially acidulated with 50 and 70% of the required H2SO4 for complete acidulation. The unreacted rock residue was isolated by subsequent extractions with water and alkaline ammonium citrate solution. P solubility in 2% formic acid of this residues was reduced as compared to the original Khouribga phosphate rock. This ‘loss in(More)
The effects of three compounds, digitolutein (1), rubiadin 1-methyl ether (2) and damnacanthal (3) extracted from the stem bark and the roots of Morinda lucida Benth. on the growth of Plasmodium falciparum in vitro were investigated. The number of parasites (schizonts) decreased significantly in a dose-dependent manner, and 100% of inhibition was obtained(More)
We studied the effects of pretreating soil samples (field-fresh, drying at 40° and 105°C, freezing/thawing) on N mineralization in an incubation experiment and on the dynamics of the organic N fraction extracted by K2SO4 solution. The soil samples were collected from plots in a long-term field experiment with the application of mineral fertilizer and(More)
The solubility and mobility of three phosphate fertilizers [superphosphate (SP), Ca-Mg phosphate (Ca-Mg-P) and diammonium phosphate (DAP)] with or without combination of farmyard manure (FYM) and/or farmyard manure juice (FYMJ) in two paddy soils (Ultisol and Entisol) from the Zhejiang Province of China were determined. Incubation experiments were conducted(More)
Alkoxyflavonols were synthesized by the Algar-Flynn-Oyamada (AFO) cyclization of chalcones. Hydroxyflavonols were prepared by dealkylation of methoxyflavonols by refluxing in hydroiodic acid. The alkoxyflavonols 3-hydroxy-2-(2,3,4-trimethoxyphenyl)-4H-chromen-4-one (6), 2-(4-ethoxyphenyl)-3-hydroxy-4H-chromen-4-one (7),(More)
By ray-tracing methods we have investigated various configurations of Wolter I type x-ray telescopes. For the criterion of image quality the shape of the line spread function has been chosen. The angular resolution we find herewith in a large region of the basic parameters appears to be more than three times higher than results from the rms blur circle(More)