Browsing Qatar University Science Journal - [From 1981 TO 2007] by Subject "الفيزياء"
Now showing items 21-40 of 40
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Microwave Spectra of 13CH3C15N and 13CH3 13C 15N Molecules In the Frequency Range 17-95 GHz
( Qatar University , 2002 , Article)Some microwave frequencies of the v^ + Vg vibrational combination band for the two isotopes CH^C N and CH^ C N of methyl cyanide were measured in the frequency range 17-95 GHz, for the transitions AJ = 1<-0, AJ = 2<-1, AJ ... -
Mossbauer Effect Study of Libyan Desert Silica Glass
( Qatar University , 1981 , Article)The Mossbauer effect and X-ray fluorescence techniques are applied to study the Libyan Desert Silica Glass. The X-ray flourescence proved the existence of 13 elements in each sample of five glass types with differences in ... -
Mossbauer Effect Study of the Cations Distribution and its Influence on the Electric Field Gradient of the Cdx Co1-x Ferrite System
( Qatar University , 1982 , Article)In the ferrite system Cd,Co,_x Fe; 04 (X=0.0, O.I, 0.2, ....... , 1.0). it was found that the introduction of Co2'1' decrease the EFG at the octahedral B-site. This was attributed to the distributions of the different ... -
Mossbauer Effect Study of the Hyper fine Structure of the Different Phases of Iron in the Portland Cement Produced in Qatar
( Qatar University , 1981 , Article)Various samples of the raw materials used in the manufacture of Portland cement in Qatar, the clinker produced and the cement itself were studied by using Mossbauer Effect and X-ray diffraction analysis in order to investigate ... -
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 ... -
ON THE CRYSTAL AND HYPERFINE PARAMETERS OF THE HEXAGONAL Ba Cax Sr1_xFe4 O8 MONOFERRITES
( Qatar University , 1983 , Article)The alkaline earth monoferrites BaCaxSr1-xFe4O8 with X = 0,0.5and 1, were studied by Mossbauer spectroscopy and neutron diffractometry over a wide range of temperatures (78 - 900 K). The lattice constants were obtained ... -
On Using the One-Exposure Method for Stress Measurements by X-Rays in Technology and Scientific Research
( Qatar University , 1982 , Article)The paper discusses the connection between macroscopic internal stresses and the technological character of technical materials. The basic theoretical relations which are used with X-Ray tensiometry of macroscopic internal ... -
The Optical and Electrical Properties of Low Density Polyethylene Films in CuSo4 Solution
( Qatar University , 2005 , Article)The optical and electrical properties of pure and treated low density polyethylene (LDpE) were investigated. These measurements have been carried out at various times of immersion for LDPE films in 10% solution of CuSO+. ... -
Optical Properties Of Oxidated Blown Asphalt Films
( Qatar University , 1996 , Article)Films of purified blown asphalt of high grades of oil and the accompanied adulterated particles derived from its manufacturing process, that is, it was purified 98%. This study focused on optical properties in the wavelength ... -
p-cds/n-Si Anisotype Heterojunction solar cells wih Efficiency of 6.4%
( Qatar University , 2005 , Article)In the present paper, p-CdS/n-Si heterojunction solar cells are prepared for the first time by the spray pyrolysis technique. Using such low-cost method, cells with 6.4'/o AM1 conversion efficiency ina O.ZZ fill factor ... -
Studies On The Decay Of 241Am
( Qatar University , 1989 , Article)The gamma-spectrum of '"Np following the <X -decay of "'Am has been studied using hyper pure Ge-detector and Ge-NaI(Tl) coincidence spectrometer. Some recently reported weak gamma transitions are confirmed, besides two ... -
A Study Of Atmospheric Transparency Over Qena In Upper Egypt
( Qatar University , 1995 , Article)Atmospheric transparency over Qena/Egypt has been studied for direct solar radiation values . which were calculated from global and diffuse solar radiation measurements . The mean monthly of the instantaneously transparency ... -
Study of Magnetic Properties and Lattice Dynamics of the Cdx Co1-x Ferrite System by MossbauerEffect
( Qatar University , 1981 , Article)The magnetic properties and lattice dynamics of the spinel ferrite system Cdx Coi-x Fe^ 04 (x = 0.0, 0.1, . . . , and 1.) were studied in the temperature range between 78 to 800°K. The results showed that the samples with ... -
Study of the Hydration of Blast-Furnace Slag Cement and Portland Cement by Mossbauer Spectroscopy
( Qatar University , 1982 , Article)Mossbauer spectra have been measured for the hydrated blast-furnace slag cement and Portland cement pastes at different times of hydration of 1. 3. 7. 28 and 90 days. The spectra showed the existence of iron atoms, Fe3 (T) ... -
Study The Effect of Classical And Rapid Thermal Annealing on The Electrical Characteristics of P-Ge/P-si Heterojunction
( Qatar University , 2002 , Article)This paper describes the effect of classical thermal (CTA) and rapid thermal annealing (RTA) on the electrical characteristics (I-V, C-V) of isotype Ge/Si heterojunction. The I-V characteristics were improved after annealing ... -
Thermoluminescence (TL) Response Of Gamma-Irradiated Raw Material And The Influence Of Doping By Different Activators
( Qatar University , 1994 , Article)Thermoluminescence of raw materials has been frequently employed to determine the exposure dose as well as effective energy of gamma radiation. In this work, thermoluminescence (TL) properties of cement clinker (C) and its ... -
Variation Of The Electrical Properties Of Manganese Thin Films With Deposition Conditions
( Qatar University , 1989 , Article)The behaviour of the electrical properties of manganese thin films of different thickness (240 - 1500 A) evaporated under different deposition conditions was studied. The effect of the rate of evaporation (1-7 A/s), the ... -
y - Irradiation Effect On The Ferroelastic High Temperature Phase In LiKSO4 Crystals
( Qatar University , 1992 , Article)The effect of •y -irradiation on the thermodynamic parameters of LiKSC>4 single crystals, in the high temperature range 300-1000 K, is investigated. The results show that T,; as well as Cp decrease with dose rate. However, ... -
استخدام ظاهرة الرنين النووي (ظاهرة موسباور) في مجمال دراسة فخار الآثار القديمة
( Qatar University , 1981 , Article)أصبح استخدام الطرق العلمية الموضوعية لازماً لتأكيد النتائج الذاتية التي يتوصل إليها علماء الآثار، وطريقة طيف موسباور المستخدمة في البحث الحالي تعتبر أحدث الطرق العلمية الفيزيائية التي استخدمت في مجال دراسة الفخار الذي عثرت ...