تصفح College of Arts & Sciences حسب تاريخ النشر
السجلات المعروضة 21 -- 40 من 3413
-
Substituted phenols as corrosion inhibitors for copper in nitric acid
( 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 ... -
Distribution and ultrastructure of neurosecretory cells in the cerebral ganglion of the earthworm
( 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 ... -
A short critique of the Crescent English Course
( 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 ... -
A study of the interlanguage of some Arabic students of English
( 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
(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. -
Selective determination of thiamine (vitamin B1) in pharmaceutical preparations by direct potentiometric argentometric titration with use of the silver-silver sulphide ion-selective electrode
( Elsevier , 1989 , Article)A simple and selective argentometric titration method is described for determination of thiamine (vitamin B1), based on direct potentiometric titration in alkaline media (⩾0.5M) in which a chemical transformation takes ... -
Thiamine-reineckate liquid membrane electrode for the selective determination of thiamine (vitamin B1) in pharmaceutical preparations
( The Royal Society of Chemistry , 1989 , Article)The construction and electrochemical response characteristics of a liquid membrane electrode for thiamine (vitamin B1) based on the formation of an ion pair between the thiamine cation and the reineckate anion in nitrobenzene ... -
Amphetamine Selective Electrodes Based on Dibenzo-18-crown-6 and Dibenzo-24-crown-8 Liquid Membranes
( American Chemical Society , 1989 , Article)Two novel membrane electrodes highly sensitive and selective for amphetaminium cation are developed and electrochemically evaluated according to IUPAC recommendations. These electrodes Incorporate amphetamine-dibenzo-18-crown-6 ... -
Liquid membrane electrodes for the selective determination of nicotine in cigarette smoke
( The Royal Society of Chemistry , 1989 , Article)Five liquid membrane electrode systems responsive to the nicotinium cation are described. These electrodes are based on the use of the ion-association complexes of the nicotinium cation with tetraphenylborate, 5-nitrobarbiturate, ... -
Polarization resistance study of inhibition of corrosion of lead by sodium benzoate in 0.1 M sodium hydroxide solution
( Council of Scientific and Industrial Research , 1989 , Article)The effect of sodium benzoate (SB) as an inhibitor of corrosion of lead in 0.1 M NaOH solution has been investigated by using the polarization resistance technique. The concentrations of SB employed are in the range 1-5 × ... -
The Influence of Cation Substitution on the Magnetic Behaviour of Magnesium Ferrite
( 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−
( 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 ... -
Constituents of plants growing in Qatar XVII anti-inflammatory and cytotoxic activities of extracts of thirty indigenous species
( Taylor & Francis , 1990 , Article)Thirty plants, indigenous to Qatar, were extracted separately with hexane, chloroform and ethanol. The dried extracts were examined for potential anti-inflammatory activities both in vitro by their ability to inhibit ... -
Vegetation composition of a maritime salt marsh in Qatar in relation to edaphic features
( 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
( 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 ... -
Helminth parasites of fishes from two inland lakes in Egypt
( 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, ... -
A review of process and production in SL studies
( Qatar University , 1990 , Article) -
Constituents of plants growing in Qatar - Part XIX. Flavonoids of Glossonema edule N. E. Br.
( Springer Nature , 1990 , Article)The study of the flavonoids of the unripe fruits of Glossonema edule, resulted in the isolation and identification of apigenin 6,8-di-C-glucoside (violanthin) and luteolin 7-O-glucoside. © 1990 Kluwer Academic Publishers. -
Guaianolides from Centaurea sinaica
( Elsevier , 1990 , Article & Report)Three sesquiterpene lactones were isolated from the aerial parts of Centaurea sinaica: amberboin, chlorohyssopifolin A and sinaicin. The latter is reported for the first time. -
معوقات التنمية الصناعية للقطاع الخاص في دولة قطر
( جامعة الإمارات العربية المتحدة- العين , 1990 , Conference Paper)توجه القطاع الخاص في دولة قطر نحو الاستثمار في القطاع الصناعي بشكل أسرع من ذي قبل بسبب دعوة الحكومة ضمن سياساتها التنموية الجديدة في فترة شهدت ضعفا في الايرادات العامة للدولة بسبب الانخفاض الكبير لأسعار النفط ووصولها الى ...