Now showing items 1-20 of 1687

    • Synthesis and biological activity of some new 3-and 6-substituted coumarin amino acid derivatives. Part I 

      El-Naggar, A. M.; Ahmed, F. S. M.; El-Salam, A. M. A.; Radi, M. A.; Latif, M. S. A. ( Wiley-Blackwell , 1981 , Article)
      The synthesis of 6-nitrocouarrain-3-CO-amino acids and their corresponding methyl esters (II-XVII) and some dipeptide methyl esters (XVIII-XXVI) are described. 6-(N-Tosyl- or N-phthalylaminoacyl)aminocoumarin-3-carboxylic ...
    • Synthesis and biological activity of some new aminoacylcarbazole derivatives. Part I 

      El-Nagger, A. M.; Ahmed, F. S. M.; El-Salam, A. M. A.; El-Gazzar, M. A. ( Wiley-Blackwell , 1982 , Article)
      The syntheses of different 9-(N-phthalyl- or N-tosyl- or free aminoacyl)carbazoles and the corresponding derivatives of 3,6-dinitrocarbazoles and some derivatives of 3,6-diamino-9-(N-phthalylaminoacyl)carbazoles (II-XXXII) ...
    • Absolute evaluation of ferrous and ferric concentration in Ca amphibole 

      Bahgat, A. A.; Fayek, M. K. ( WILEY-VCH Verlag , 1982 , Article)
      Studies are made of M?sshauer absorption of 57Fe in a Ca-amphibole schist sample at room and liquid nitrogen temperatures. The absolute concentration and the recoilless fraction for ferrous and ferric cations are determined ...
    • Ventifacts distribution in Qatar 

      Babikir, A. A. A.; Jackson, C. C. E. ( John Wiley & Sons, Ltd , 1985 , Article)
      This study attempts to investigate the distribution of ventifacts in Qatar. It is believed that ventifacts are confined to the areas within about 5 km of the Miocene or Mio-Pliocene Hofuf formations and the spreads of ...
    • Mössbauer study of ZnxNi5/3−xFe1Sb1/3O4 spinel ferrite 

      El Nimr, M.K.; Saleh, H.A.; Fayek, M. K. ( Springer Verlag , 1985 , Article)
      The antimony substituted nickel ferrite ZnxNi5/3–xFe1Sb1/3O4 with different values ofx are prepared, checked by x-ray and studied with57Fe Mössbauer spectroscopy over a wide temperature range. Characteristic spectra of ...
    • Mössbauer effect study of Li21+Me4+Fe63+O122−spinels 

      Saleh, H.A.; El Nimr, M.K.; Nada, N.; Fayek, M. K. ( Baltzer Science Publishers, Baarn/Kluwer Academic Publishers , 1986 , Article)
      Mossbauer effect spectra are obtained for the cubic ferrites Li2 Me Fe6 O12 (where Me4+ is one of the tetravalent elements Ge, Si and Ti) at 78K up to their magnetic transition temperatures. In a rather large temperature ...
    • Polarization Resistance Study on Copper Corrosion in Aqueous Potassium Hydrogen Phthalate Solution 

      Mouhad, M. Y.; Bekheet, A. M.; Soliman, S. A. ( WILEY-VCH Verlag , 1987 , Article)
      The effect of temperature on corrosion of copper in 0.1 M aqueous solution of potassium hydrogen phthalate (KHPh) has been investigated using polarization resistance technique. it was found that that the corrosion rate in ...
    • A short critique of the Crescent English Course 

      Al-Buainain, Haifa ( Qatar University , 1988 , Article)
      This paper is a short critique of the "Crescent English Course", Pupils Book 2. It falls into two parts. The first is information about the course; its aims, organization and some of its general characteristics. The second ...
    • Distribution and ultrastructure of neurosecretory cells in the cerebral ganglion of the earthworm 

      Al-Yousuf, S. ( Wiley Subscription Services, Inc., A Wiley Company , 1988 , Article)
      Neurosecretory (Nsy) cells within the cerebral ganglion of Lumbricus terrestris were classified ultrastructurally. The Nsy cells within the subesophageal ganglion, nerve cord ganglion, and the peripheral nervous system ...
    • Effects of herbicide and timing of removal on interference between barley and weeds 

      ISMAIL, A. M. A.; HASSAN, A. H. A. ( Blackwell Publishing Ltd , 1988 , Article)
      Field experiments were done during the rainy season of 1984�85 and 1985�86 at Harma, Qatar. A weed survey of barley fields was conducted with the primary purpose of identifying the weed vegetation present. The effects of ...
    • Substituted phenols as corrosion inhibitors for copper in nitric acid 

      Fouda, A. S.; Mohamed, A. K. ( WILEY-VCH Verlag GmbH , 1988 , Article)
      The dissolution of copper in nitric acid solution in the presence of resorcinol, o, p-aminophenols, catechol, o-cresol and salicylaldehyde as corrosion inhibitors has been studied by galvanostatic polarization and weight ...
    • Evidence for some prostaglandins in Allium sativum extracts 

      Al-Nagdy, Sohair A.; Abdel-Rahman, M. O.; Heiba, H. I. ( John Wiley & Sons, Ltd. , 1988 , Article)
      Homogenized garlic (Allium sativum Linn.) was extracted successively with organic solvents and the prostaglandin-rich fraction separated. Fractionation of the extract with column chromatography was performed. TLC of the ...
    • A study of the interlanguage of some Arabic students of English 

      Al-Buainain, Haifa ( Qatar University , 1988 , Article)
      In this study, the contrastive analysis method is used to investigate the lnterlanguage (IL) developmental sequences of the acquisition of some aspects of English by Arabic-speaking learners. The learners, whose language ...
    • Chemical survey of some plants Growing in Qatar 

      Rizk, A.M.; Heiba, H.I.; Al-Easa, H.S. (1989 , Other)
      Fifty one plants growing in Qatar, belonging to thirty families, were surveyed for alkaloids, anthraquinones, coumarins, flavonoids, tannins and saponins. The medicinal uses of these plants arereported.
    • The Influence of Cation Substitution on the Magnetic Behaviour of Magnesium Ferrite 

      Fayek, M.; Elnimr, M.; Nada, N.; Saleh, H.; Eid, Y. ( WILEY-VCH Verlag GmbH & Co. , 1989 , Article)
      New polycrystalline specimens of the ferrites Mg1.5Fe1Si0.5O4, Mg1.5Fe1Ge0.5O4, Mg1.5Fe1Ti0.5O4 and Mg1.66Fe1Sb0.33O4 have been prepared and studied by nuclear gamma ray resonance technique, over a wide temperature range. ...
    • On the Valence State of Iron in Sr0.52+Ca0.52+Fe0.54+ Me0.54+O32− 

      Fayek, M. K.; Elnimr, M. K.; El Hamalawy, A.; Sekina, M. A. ( WILEY-VCH Verlag GmbH & Co. , 1989 , Article)
      Powder samples of Sr0.5Ca0.5Fe0.5Me0.5O3 (Me = Co, Zr or Mn) and Sr0.3La0.7FeO3 are investigated by X-ray diffraction and Mossbauer effect spectroscopy. Analysis of the completely ordered spectra suggested three kinds ...
    • Vegetation composition of a maritime salt marsh in Qatar in relation to edaphic features 

      Abdel-Razik, M.S.; Ismail, A. M. A. ( Blackwell Publishing Ltd , 1990 , Article)
      Coverpercentage values for plant species were estimated using the line-intercept method along two belt transects starting at the lower mangrove frontier and ending at the upper height of the salt marsh. Twelve perennial ...
    • Inhibitive Effect of Butyltin Trichloride on Dissolution and Localized Corrosion of Aluminium in Sodium Hydroxide and Hydrochloric Acid 

      Mourad, M.Y.; Ibrahim, E.H.; Seliman, S.A. ( WILEY-VCH Verlag , 1990 , Article)
      The dissolution of aluminium in sodium hydroxide and hydrochloric acid in the presence of butyltin trichloride as corrosion inhibitor has been studied by hydrogen evolution and thermometric methods. Experimental findings ...
    • A review of process and production in SL studies 

      Al-Buainain, Haifa ( Qatar University , 1990 , Article)
    • Helminth parasites of fishes from two inland lakes in Egypt 

      Saoud, Mohamed Fathy A.; Ashour, A. A.; Ramadan, M.M.; Lamloom, D.A.M. ( Nihon Kiseichu Gakkai , 1990 , Article)
      Results of helminthological examination of 1243 fishes, caught from two inland lakes, with unique and contrasting hydrobiological features at Fayoum Governate in Egypt, are presented. General incidence of trematodes, ...