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السجلات المعروضة 31 -- 40 من 197
Charge transfer complex formation constants of edta with methylviologen And its zwitterionic derivatives
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Qatar University
, 1994 , Article)
In the photochemical cycle of the labelled, tris (2,2'bipyridine) ruthenium(II), Ru(bpy)32+, the photo excited label is oxidized through electron transfer quenching by methylviologen (l,l'-dimethyl-4,4'-bipyridinium dication, ...
Effect of gamma radiation on the morphology and Thermophysical properties of the pollen wall of Phoenix dactylifera L.
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Qatar University
, 1994 , Article)
Pollen grains of Phoenix dactylifera were exposed to different doses of gamma radiation (250,500,1000 rad and 1 M rad). To access the effect of radiation on the external morphology of the pollen grains, they were examined ...
Synthesis of some new oximes, thiocarbamates, pyrazolyloxy, isoxazolyloxy, Pyrmidyloxy and pyridyloxy quinolines
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Qatar University
, 1994 , Article)
The reaction of 1 or its corresponding chalcones 3a-c with hydroxylamine in boiling pyridine gave the oximes 2 or 5a-c respectively in almost quantitative yield. When both 2 and 5a-c were reacted with phenylisothiocyanate, ...
Multielement Analysis Of Suspended Particulates In Doha (Qatar) Air Before And During The Gulf War
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Qatar University
, 1994 , Article)
Efforts have been made to study the effect on Qatar atmosphere from the burning of Kuwait oil fields during the Gulf war. Analysis of suspended air particulates was done by X-ray fluorescence technique. Eight elements were ...
Electrochemical behaviour of some pyrimidine derivatives: polarographic reduction of 1, 3-dimethyl-2, 4, 6(1h, 3h, 5h) pyrimidinetrione and its substituted 5-phenylazo
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Qatar University
, 1994 , Article)
The polarographic behaviour and spectrophotometric pKa of 1,3-dimethyl barbituric acid and 5-phenylazo substituted products were investigated in buffer solution of pH ~ 2-11. The results revealed an azo form of the substituted ...
Aluminium Nitrate As External Absorbent In The Microdetermination Of Carbon And Hydrogen In Organofluorine Compounds
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Qatar University
, 1994 , Article)
Silica gel loaded with saturated A1(NO3)3- 10. H2O solution proved to be an efficient absorbent for the elimination of the interference of fluorine in the microdetermination of carbon and hydrogen in organofluorine compounds. ...
Effect Of Gossypol, Apogossypol And Gossypolone On Fatty Acids Pattern Of Lipid Fractions In Rat Serum And Seminal Fluid
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Qatar University
, 1994 , Article)
he fatty acids pattern of the total lipid fractions of male rat serum and seminal fluids were studied under the effect of gossypol and some of its metabolites (Apogossypol and gossypolone). The applied dose of gossypol and ...
Embryonic Development Of The Olfactory Organ In Mice
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Qatar University
, 1994 , Article)
The development of the olfactory organ in the prenatal stages of mice (Patch/normal Balb/c) was studied. Eight stages were selected for this study; they are 9,10,11,12,13, 14,16 and 18 days of gestation.
At 9 days of ...
Scanning electron microscopy of the egg-shell of the fly synthesiomyia Nudiseta (wulp)
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Qatar University
, 1994 , Article)
The ultrastructure of the egg-shell of the fly Synthesiomyia nudiseta has been studied by scanning electron microscopy. The surface of the outer chorion is highly ridged, grooved and has a reticulate appearance except at ...
Crystal hydration and vacancy enhanced isotopic exchange reactions in Heterogeneous solid - liquid systems
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Qatar University
, 1994 , Article)
The rate of some heterogeneous isotopic exchange reactions can be enhanced by the simultaneous hydration of the solid participating in the exchange process. The results presented here show that the concomitant hydration ...