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51.
Bianchi Type-III cosmological models for perfect fluid distribution with time dependent displacement field in the framework
of Lyra geometry are investigated. To get the deterministic model of the universe, we have assumed two conditions (i) shear
(σ) is proportional to the expansion (θ). This leads to B=C
n
where B and C are metric potentials and n is a constant. (ii) Universe is filled with barotropic fluid distribution which leads to p=γ
ρ, 0≤γ≤1, p being isotropic pressure and ρ the energy density. The physical and geometrical aspects of the model with a special case and singularities in the models
are also discussed. 相似文献
52.
J. Klusoň Kamal L. Panigrahi 《The European Physical Journal C - Particles and Fields》2011,71(3):1595
We continue our study of the Lorentz-breaking string theories. These theories are defined as string theory with modified Hamiltonian
constraint which breaks the Lorentz symmetry of target space-time. We analyze the properties of this theory in the target
space-time that possesses isometry along one direction. We also derive the T-duality rules for Lorentz-breaking string theories
and show that they are the same as that of Buscher’s T-duality for the relativistic strings. 相似文献
53.
Mounir A. I. Salem Wafaa M. Abdou Tarik E. Ali Azza A. Kamal Reham F. Barghash 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1007-1016
Abstract Fragmentation pathways of 14 organophosphorus compounds derived from diethyl spiro[pyrimidino[5,3][1,2]oxazole] phosphonates, diethyl (oxazolo[5,4-d]pyrimidine-4,6-dione)phosphonates, and diethyl (pyrimidino[4,5-b][1,4] oxazine)phosphonates were investigated by electron impact mass spectrometry (EI-MS). The intensity of the recorded molecular ion peaks showed various values depending on the nature of the compounds. Characteristic fragment ions were formed by successive loss of simple functional groups followed by decomposition of heterocycles connected to pyrimidine rings. 相似文献
54.
Kh. M. Hassan A. M. Kamal El-Dean M. S. K. Youssef F. M. Atta M. S. Abbady 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):283-289
Abstract Thienopyridine oxazinone (1) has been prepared and explored as a precursor by its reaction with some reagents namely, ammonium acetate, aliphatic amines, aromatic amines, hydrazine hydrate, thiosemicarbazide, and ethyl glycinate to give pyridothienopyrimidines (11-VII). The pyrimidinone compound (11) was converted to the 4-chloro derivative (X) by its reaction with excess POCl3 Interaction of the 4-chlorocompound (X) with some reagents namely, hydrazine hydrate, methyl amine, aniline, sodium thiophenolate, ethyl glycinate, thiosemicarbazide and thiourea, yielded pyridothieno-pyrimidine derivatives (XI-XVII) substituted at 4-position, respectively. 相似文献
55.
Kamal M. El-Shaieb 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):675-681
A mixture of equimolar quantities of dimethyl acetylenedicarboxylate ( 2 ) with either 2-mercaptoperimidine ( 1 ) or 2-mercaptobenzimidazole ( 5 ) was heated in absolute benzene in the presence of triphenylphosphine as a catalyst under reflux conditions for 1 h (the reaction was monitored by TLC until the consumption of the starting materials). The solvent was concentrated under vacuum and the residue was subjected to chromatographic plates using toluene-ethylacetate (2:1) as an eluent. The products in each reaction were separated as two migrating zones. Each zone was removed from the plate and recrystallized from the appropriate solvent. The products of the first reaction are 10-methoxy-11-oxo-11H-8-thia-7,11a-diaza-benzo[de]anthracene-9-carboxylic acid methyl ester ( 3 ) and 8-thia-7,10a-diaza-cyclopenta[a]phenalene-9,10-dicarboxylic acid dimethyl ester ( 4 ), while the products of the second reaction are 3-methoxy-4-oxo-4H-1-thia-4a,9-diaza-fluorene-2-carboxylic acid methyl ester ( 10 ) and benzo[4, 5]imidazo[2,1-b]thiazole-2,3-dicarboxylic acid dimethyl ester ( 11 ). The mechanisms of the observed reactions are suggested. 相似文献
56.
Meet Kamal 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(7):548-554
A series of IPN based on poly(antimony acrylate) and poly(arsenic acrylate) have been synthesized by a sequential mode of synthesis. Formation of complex based on “polymer solvent” method reflects the contraction of the polymer coils by determining the value of mutual interaction constant (kAB) in different solvents such as dimethylsulphoxide (DMSO) (kAB=0.60); dimethylformamide (DMF) (kAB=0.42); dioxane (kAB=0.26) predicting weak Vander Waal interaction. The scanning electron microscopy reveals dual phase morphology of both metal acrylates. The infrared spectrum indicates characteristic frequencies of (>C?O) at 1730 cm?1,thus giving structural evidence for IPN. The properties namely percentage swelling, average molecular weight between crosslinks(Mc),Young's modulus, increases with concentrations of linear polymer(polyantimony acrylate) and initiator (benzoyl peroxide). However, it decreases with concentrations of monomer (arsenic acrylate) and crosslinker (divinyl benzene).The value of activation energy calculated from thermo gravimetric analysis is 15 KJ/mol. 相似文献
57.
Hassan Talaat Ali H. Moussa M. Shalaby El-Wallid S. Sedik M. Tag El-Din Kamal 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(3):454-460
We apply the time-dependent theory to the collinear exchange reaction F + CH4 → FCH3 + H. We have performed detailed calculations on two-dimensional potential surfaces representing the ground electronic potentials of the collinear F + CH4 → FCH3 + H reaction, at incident energies. Transmission coefficients range from zero to unity, depending upon the incident energy. Normal modes of vibrations are displayed along the reaction path. 相似文献
58.
Rinki Bhadra Vidya Nand Singh Bodh Raj Mehta Pranayee Datta 《Journal of Dispersion Science and Technology》2013,34(9):1202-1207
ZnO nanocrystals are synthesized using the quenching method. The properties of the grown nanocrystals are studied using ultraviolet-vis spectroscopy, x-ray diffraction, photoluminescence, electron diffraction, energy dispersive x-ray spectroscopy, and high resolution transmission electron microscopy. Current-voltage characteristics of the prepared samples are studied for investigating the possible application of the samples as switch and memristor. 相似文献
59.
Kareem AbuBakr Soliman Howida Kamal Ibrahim Mahmoud Mohamed Ghorab 《Journal of Dispersion Science and Technology》2013,34(8):1127-1133
Risperidone is an atypical antipsychotic drug used to treat schizophrenia. This study aims to formulate risperidone as effervescent tablets to improve patient compliance. Different nanoemulsion combinations were loaded with risperidone to improve its poor water solubility then adsorbed on Aeroperl. The formula showing highest drug dissolution was formulated as effervescent tablets. Factorial design was applied for different tablet formulation variables and the prepared formulae were tested for different criteria in comparison with their corresponding formulae containing drug without nanoemulsion formulation. Statistical analysis was used to determine the most desirable tablet formula considering its Carr index, effervescence time, and drug release. 相似文献
60.
Vivek T. Humne Kamal Hasanzadeh Pradeep D. Lokhande 《Research on Chemical Intermediates》2013,39(2):585-595
Selective O-deallylation of dihydropyrazoles has been achieved by use of iodine (10 mol%) in PEG-400 as ecofriendly solvent. Iodine (10 mol%) in dimethyl sulfoxide at 100 °C also afforded O-deallylation with aromatization compatible with highly reactive N-allyl and formyl groups. The function of iodine in the synthesis of substituted pyrazoles under different conditions is described. 相似文献