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Now showing items 41-50 of 109
Guaianolides from Picris radicata
(
Elsevier Science Ltd.
, 1996 , Article)
The methylene chloride-methanol (1:1) extract of the aerial parts of Picris radicata Forssk afforded two new guaianolides. The structures were established from spectral data.
Possible evidence for the existence of a hairy layer at the surface of polymer latex particles
(
John Wiley & Sons, Ltd.
, 1998 , Article)
In this work, an attempt is made to verify the existence of a hairy layer at the surface of polymer latex particles, and determine its thickness under different conditions. Two systems have been studied. In one system, ...
Mercury pollution in doha (Qatar) coastal environment
(
Wiley Periodicals, Inc.
, 1994 , Article)
Surface water and sediment samples were collected from the Doha coastal area and analyzed for content of physico-chemical forms of mercury. Dissolved reactive Hg (2.9 ng L?1) represented 81.0% of the total dissolved Hg ...
Expansion of fisheries in Qatar (1980-1992): Growth of an artisanal fleet and closure of a trawling company
(
Elsevier Science B. V.
, 1995 , Article)
Total fish landings in Qatar increased from 1736 t per annum in 1980 to 7845 t in 1992. Ninetythree percent of this growth was due to an increase in the artisanal fleet exemplified by increases in: (i) numbers of vessels ...
Ac-conductivity analysis of the effects of partial dealumination and γ-irradiation on the electric features of HZSM-5
(
Elsevier
, 1996 , Article)
For illustrating such titled effects, analysis of the electric impedance, capacitance, and dielectric loss dependences on the frequency W (0.1–100 kHz) and temperature T (373–673 K) is correlated at 0.8 V for γ-irradiated ...
Evidence by ac-conductivity for the higher mobility of boron (over aluminium)-associated Brønsted sites in boron-modified HZSM-5
(
Elsevier
, 1996 , Article)
A correlation ac-conductivity analysis is performed at 102–105 Hz, 373–613 K and 0.8 V for characterizing the effect of increasing boron incorporation in HZSM-5 lattice on altered electric features in BZSM-5 samples of ...
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.
Flavonoids from Centaurea sinaica
(1992 , Article)
Four Newly isolated flavonoids from Centaurea sinaica
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 ...
Constituents of Plants Growing in Qatar, Part XXX: A New Iridoid from Cistanche Phelypaea (L) COUT
(1995 , Article)
New iridoid named phelypaeside (1) was isolated from the dried aerial parts of Cistanche phelypae (Orobanchaceae) growing in Qatar