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Now showing items 1-10 of 11
A 6th-order local approximation by a cubic curve
(
Qatar University
, 1997 , Article)
We derive and present a MAPLE program for the construction of a parametric cubic polynomial curve which has sixth-order contract with a given smooth curve at a given point, thus providing a local sixth-order approximation ...
(−)-Paniculatol, a new ent-labdane bromoditerpene from Laurencia paniculata
(
Elsevier Science Ltd.
, 1997 , Article)
(−)-Paniculatol, 1, an unusual tricyclic bromoditerpene belonging to the ent-labdane series has been identified in the red alga Laurencia paniculata collected on Qatari coasts, Arabian Gulf. The structure displays an unusual ...
Fatty acid composition of twelve algae from the Coastal Zones of Qatar
(
Kluwer Academic Publishers
, 1997 , Article)
Fatty acid composition of twelve algal species from two different classes were determined. Three Chlorophyta species(Axetabularia calyxulux, Cladophors sericoides and Dictyosphaeria cavernosa) and nine Phaephyta species ...
Ground- and excited-state properties of some 3,4-dihydro-1-(2-p-substituted benzylidene)naphthalenones: substituent and environmental effects
(
John Wiley & Sons, Ltd.
, 1997 , Article)
Electronic absorption and steady-state fluorescence emission of seven 3,4-dihydro-1-(2-p-substituted benzylidene)naphthalenones (1–7) show sizable solvent dependence. The charge-transfer (CT) absorption maxima of these ...
Optical and electrical properties of a new polymer
(
John Wiley & Sons, Inc.
, 1997 , Article)
Thin film of poly (5-isopropylidenecyclo-1,4-vinylene-2,3-dicarboxylicacidamide-s-methyl hydrazinecarbodithioate) (II) (Scheme 1) of 5 μm thickness was prepared. The dielectric properties of the prepared sample were studied ...
Radon concentration determination in some dwellings of Doha city of Qatar
(
Elsevier
, 1997 , Article)
Yearly average radon concentrations have not been reported yet in Qatar. Only few measurements on indoor radon concentrations have been conducted during the autumn season in 1992. To complete these measurements a determination ...
Positron annihilation lifetime study of pure and treated polyvinyl chloride
(
scientific.net
, 1997 , Article)
Positron annihilation lifetime technique (PAL) has been applied to investigate the behavior of the free volume in pure and doped polyvinyl chloride (PVC) as a function of Pb concentration and temperature. It is noticed ...
Determination of glafenine in dosage forms and serum by thin layer densitometry and high performance liquid chromatography
(
Elsevier
, 1997 , Article)
New thin layer densitometry and high performance liquid chromatography (HPLC) methods are described for quantitative determination of glafenine in dosage forms in the presence of its photo-degradation products and in serum ...
Mercurimetric potentiometric determination of barbiturates using a solid-state iodide ion-selective electrode
(
Taylor and Francis Inc.
, 1997 , Article)
A simple potentiometric method is described for mercurimetric titration of barbiturates using a solid-state iodide ion-selective electrode. The optimum titration conditions involve the use of a borate buffer of pH 9-10 as ...
Plastic Membrane Electrodes for the Potentiometric Determination of Codeine in Pharmaceutical Preparations
(
Springer New York
, 1997 , Article)
Four PVC membrane electrode systems responsive to codeinium cation are described. These electrodes are based on the use of the ion-association complexes of the codeinium cation with tetraphenylborate and reineckate ...