تصفح Qatar University Science Journal - [From 1981 TO 2007] حسب العنوان
السجلات المعروضة 435 -- 454 من 770
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Neurosecretory Cells In Certain Earthworms Species (Oligochaete)
( Qatar University , 1987 , Article)Typical Neurosecretory cells of the cerebral ganglion were studied in three oligochaete families: A. porrectodea caliginosa, Dendrodrilus rubidus: (Lumbricidae)'; Amynchas corticis : (Megascolidae); Dichogaster bolaui: ... -
Neutron Diffraction and Mossbauer Effect Study of a Cobalt Substituted Zinc Ferrite
( Qatar University , 1982 , Article)The mixed cubic ferrite Zno.g5 €00.15 Fez 04 is studied by neutron diffraction and Mossbauer effect techniques at the temperature range 4.2 - 293 °K. The obtained spectra by both methods at low temperature show a long range ... -
Neutron Diffraction And Mossbauer Effect Study On A Mixed Rare Earth Garnet
( Qatar University , 1983 , Article)A powder sample of Y^YbFesO,; was prepared using the ceramic technique. X-ray diffraction pattern showed a single phase of the garnet type structure with a lattice constant 12.323 A". Specific heat for this composition was ... -
New Contributions To The Geology, Geochemistry And Tectonic Setting Of The Aswan Granites, Southern Egypt
( Qatar University , 1990 , Article)The Aswan granitic rocks occupy a region in southern Egypt between the stable Archaean craton of the south Western Desert and the less stable Pan-African belt of the south Eastern Desert. They include light-grey medium ... -
A New Liquid Membrane Electrode For Selective Determination Of Caffeine
( Qatar University , 1984 , Article)A new liquid membrane electrode for caffeine prepared from a solution of caffeine-picrylsulfonate ion-pair complex in n-octanol is developed. It exhibits Nernstian response in the range of 10'2 to lO^M caffeine with a ... -
New Potassium/Argon Ages For The Volcanic Rocks Of Halul Island (Qatar)
( Qatar University , 1988 , Article)The only rocks of igneous origin known to be exposed in Qatar are those of Halul and Shra'Auh Islands. They occur within a salt diapir and the age of these rocks is uncertain. They have generally been assigned to the Hormuz ... -
New Records Of Some Mammals From Qatar: Insectivora, Lagomorpha And Rodentia
( Qatar University , 1984 , Article)The present report deals with six native mammalian species to be recorded for the first time from Qatar. They belong to the following orders: Insectivora, Lagomorpha and Rodentia. None of these species is endemic to Qatar. -
New switching algorithm for combining new multi-step CG and self-scaling VM algorithms for non-linear optimization
( Qatar University , 1997 , Article)New interleaved CG and self-scaling VM algorithm is presented in this research which combines Al Bayati's self-scaling VM algorithm with another new multi-step CG algorithm with inexact line searches (ILS). In an interleaving ... -
A New Tetrafluoroborate Liquid Membrane Electrode For Selective Determination Of Boron
( Qatar University , 1986 , Article)The construction and performance characteristics of a new liquid membrane electrode selective for BF^ion are herein described. The electrode incorporates nitron-tetrafluoroborate ion pair complex in nitrobenzene as a liquid ... -
Night and Early Morning Flying Insects in a Residence Backyard in Doha City, Qatar
( Qatar University , 2006 , Article)Night and early morning flying insects in Doha were recorded daily, for a complete year, using a light-water trap. Two peaks of insect numbers occurred in April-May and September-October periods respectively. The lowest ... -
Night Distribution Of Certain Species Of Coleoptera As Indicated By Captures In A Light Trap At Quena
( Qatar University , 1984 , Article)The night distribution of nineteen species over a whole trapping period can be considered under the following headings: a. Early flyers b. Species with two peaks of activity. The effect of light of low intensity, temperature ... -
Nitrogen fixation in polluted sea water of Alexandria coast, Egypt.
( Qatar University , 1990 , Article)The inshore area of the Mediterranean water, west of Alexandria, Egypt, is subjected to different types of pollutants. Nitrogen fixation rate was studied in this area in relation to some environmental factors such as pH, ... -
Nitrogen Transformations as affected by some factors at cultivated soils in Saudi Arabia
( Qatar University , 2001 , Article)The influence of serial concentration of salts (0.5, 1.0 and 1.5%), application of organic matter (0.5, 1.0 and 1.5% of wheat strat) and varying soil moisture content 50, 70 and 90%) on nitrification in sandy loam soil was ... -
Nitrogen Transformations As Affected By Some Factors at Cultivated Soils In Saudi Arabia
( Qatar University , 2000 , Article)The influence of serial concentration of salts (0.5, 1.0 and 1.5%), application of organic matter (0.5, 1.0 and 1.5% of wheat straw) and varying soil moisture content (50, 70 and 90%) on nitrification in sandy loam soil ... -
Nomograms For Interpreting Gravity Anomalies Above A Finite Horizontal Cylinder
( Qatar University , 1985 , Article)The present study gives a new method for solving the inverse problem of the gravitational anomalies related to a finite horizontal cylinder, by the use of the downward continuation method. Master curves have been obtained ... -
A Note on Norland Summability of Fourier Series
( Qatar University , 1982 , Article)In this paper we consider point-wise summability in the Norlund sense of Fourier series by assuming H(n) . F(n) = o (Pn) as n--+ oo, where (H(x) = d.x g(t) dt, g(t) is continuous, non-increasing, H(x) is slowly varying, ... -
A Note On Pre-J-Group Rings
( Qatar University , 1991 , Article)Given an associative ring R satisfying a°'b = Ba" for any pair a and b of its elements, is being a positive integer, and a group G satisfying x""' = y"~1, we give a sufficient and necessary condition on the group ring GR ... -
A Note On Semi Generalized Closed Sets
( Qatar University , 1994 , Article)In the present note authors obtain some characterizations and properties of semi generalized closed sets. -
Numerical Abundance And Species Diversity Of Surface Zooplankton In The Coastal Waters Of United Arab Emirates On The Arabian Gulf A Preliminary Study
( Qatar University , 1999 , Article)Surface zooplankton of the coastal waters of the United Arab Emirates was studied bimonthly during the period September 1997 to July 1998. Species diversity, numerical abundance and seasonal dynamics were analyzed , at six ... -
A Numerical Solution For The Bending Of A Plate Using The Boundary Element Method
( Qatar University , 1992 , Article)In this paper the numercial solution for the bending of a plate is considered. The method used is called the Boundary Element Method (BEM). The BEM is a numerical method based on the boundary integral equation formulation ...
