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11.
Mohamed El Guendouzi Abderrahim Dinane Abdelfetah Mounir 《Journal of solution chemistry》2002,31(2):119-129
The mixed aqueous electrolyte system of ammonium and lithium chlorides has been studied by the hygrometric method at 25°C. The relative humidities of this system are measured at total molalities from 0.3 to 6 mol-kg– 1 for different ionic-strength fractions y of NH4Cl with y = 0.33, 0.50, and 0.67. The data obtained allow the deduction of new water activities and osmotic coefficients. The experimental results are compared with the predictions of the ECA (extended composed additivity) law proposed in our previous work. The Zdanovskii–Stokes–Robinson (ZSR), the Robinson–Stokes (RS), Reilly–Wood–Robinson (RWR), the Pitzer, and the Lietzke–Stoughton (LS II) models are also compared with our results. Predictions made using these models are, in general, consistent with our results. From these measurements, new Pitzer mixing ionic parameters are determined and used to predict the solute activity coefficients in the mixture for different ionic-strength fractions. 相似文献
12.
Mounir Maafi Belkacem Laassis Jean-Jacques Aaron M. Carmen Mahedero Arsenio Muñoz De La Peña Francisco Salinas 《Journal of inclusion phenomena and macrocyclic chemistry》1995,22(3):235-247
The photooxidation of Azure A and fluorescence properties of Azure A and its photoproduct have been investigated in aqueous media and in the presence of-cyclodextrin (-CD). The fluorescence intensity of the complex formed between the photoproduct and -CD was found to be three times higher than that of the uncomplexed Azure A photoproduct. A complex formation constant of 110±40 M–1 was calculated using the Benesi-Hildebrand treatment of the fluorescence emission data. Although the stoichiometry of the Azure A photoproduct: -CD complex was found to be 1: 1, it seems that the Azure A structure is only partially included. Calibration graphs were plotted for the free Azure A photoproduct and the photogenerated product included in -CD. The analytical parameters and quantification limits were determined. 相似文献
13.
We present pseudo-potential calculations of geometrical structures of stable isomers of LiAr
n
clusters with both an electronic ground state and excited states of the lithium atom. The Li atom is perturbed by argon atoms
in LiAr
n
clusters. Its electronic structure obtained as the eigenfunctions of a single-electron operator describing the electron in
the field of a Li+Ar
n
core, the Li+ and Ar atoms are replaced by pseudo-potentials. These pseudo-potentials include core-polarization operators to account for
the polarization and correlation of the inert core with the valence Lithium electron [J Chem Phys 116, 1839 1]. The geometry optimization of the ground and excited states of LiAr
n
(n = 1–12) clusters is carried out via the Basin-Hopping method of Wales et al. [J Phys Chem 101, 5111 2; J Chem Phys 285, 1368 3]. The geometries of the ground and ionic states of LiAr
n
clusters were used to determine the energy of the high excited states of the neutral LiAr
n
clusters. The variation of the excited state energies of LiAr
n
clusters as a function of the number of argon atoms shows an approximate Rydberg character, corresponding to the picture
of an excited electron surrounding an ionic cluster core, is already reached for the 3s state. The result of optical transitions calculations shows that the absorption spectral features are sensitive to isomer
structure. It is clearly the case for transitions close to the 2p levels of Li which are distorted by the cluster environment. 相似文献
14.
A. M. Maysa Rania Mounir M. M. Abou Zeid A. A. El Miligy 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):483-488
The effect of different polyfunctional monomers (PFMs) as enhancing agents on the properties of natural rubber/styrene-butadiene rubber blend reinforced with 40 (phr) part per hundred part of rubber, by weight of HAF carbon black and vulcanized with gamma irradiation was investigated. The coagents N,N’ methylene diacrylamide (MDA), trimethylol propane-trimethacrylate (TMPTMA) and trimethylol-methane tetraacrylate (TMMTA) were used at a constant content of 5 phr. The physico-chemical properties such as tensile strength, tensile modulus at 100 % elongation, elongation at break, gel fraction and swelling number were studied. The results indicated that the properties are greatly improved by PFMs at lower doses. TMMTA as coagent is more effective than TMPTMA and MDA. 相似文献
15.
Ahmed A. El-Asmy Yehia M. Shaibi Abdallah S. Babaqi Mohamed Mounir Salah A. Ashour 《Transition Metal Chemistry》1988,13(5):332-335
Summary The interaction of 1-benzoin-4-phenylthiosemicarbazone (H2 BPS) with some transition metal ions has been investigated. The ligand can function as a tridentate chelating agent, giving M(HBPS)2 and M(BPS). Potentiometric studies proved that the mechanism of chelation is based on hydrogen ion liberation. Spectral studies in solution show that the ligand could be used for the microdetermination of CuIIions. On the basis of magnetic and spectral data, an octahedral structure is proposed for the CoII and NiII complexes and a square-planar structure for the CuII complex. The corrosion inhibition of aluminium in Cl3CCO2H using H2BPS is studied. The electrical conductivity of H2BPS and of its complexes have been measured. The ligand shows an activation energy in the range of semiconducting materials. The antimicrobial activity of all compounds has also been demonstrated. 相似文献
16.
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
17.
Nabel A. Negm Mohamed F. Zaki Mounir A. I. Salem 《Journal of Dispersion Science and Technology》2013,34(10):1390-1395
A novel series of cationic Gemini amphiphiles containing Dischiff base species were synthesized and their chemical structures were determined using different analytical tools. Their surface properties were determined using surface tension measurements. The adsorption and micellization thermodynamic parameters were calculated using Gibb's equations at 25°C. The surface parameters were also determined including critical micelle concentration, effectiveness, efficiency, maximum surface excess, minimum surface area, interfacial tension, and emulsification power. The synthesized cationic Gemini surfactants were evaluated as bactericides for gram negative and gram positive bacteria and also against sulfur reducing bacteria (SRB). The results of the cytotoxicity of the synthesized compounds against the targeted bacterial strains were promising and completely dependent on the surface activity of these compounds. 相似文献
18.
Adnane Aouidate Adib Ghaleb Mounir Ghamali Samir Chtita Abdellah Ousaa M’barek Choukrad Abdelouahid Sbai Mohammed Bouachrine Tahar Lakhlifi 《Chemical Papers》2018,72(11):2833-2847
Ca2+/calmodulin-dependent protein kinase II (CAMKIIδ) belongs to the serine/threonine kinase family, which is involved in a broad range of cellular events in cell survival and proliferation as well as a number of other signal transduction pathways. Thus, it is regarded a promising target for treatment of cancers. In the present paper, a three-dimensional quantitative structure–activity relationship and molecular docking were applied to investigate a series of new CAMKIIδ inhibitors of pyrazolopyrimidine derivatives. The determination coefficient (R2) and leave-one-out cross-validation coefficient (Q2) of CoMSIA model are 0.676 and 0.956, respectively. The predictive ability of this model was evaluated by the external validation using a test set of eight compounds with a predicted determination coefficient \(R^{ 2}_{\text{test}}\) of 0.80, besides the mean absolute error of the test set was 0.328 log units. Docking results are in concordance with CoMSIA contour maps, gave the information for interactive mode exploration. Based on those satisfactory results, newly designed molecules were predicted with highly potent CAMKIIδ inhibitory activity, additionally, they have showed promising results in the preliminary in silico ADMET evaluations. This study could expand our understanding of pyrazolopyrimidine derivatives as inhibitors of CAMKIIδ and would be of great help in lead optimization for early drug discovery of highly potent CAMKIIδ inhibitors. 相似文献
19.
Ciprian A. Tudor Mounir Zili 《NoDEA : Nonlinear Differential Equations and Applications》2016,23(5):53
We consider a stochastic partial differential equation involving a second order differential operator whose drift is discontinuous. The equation is driven by a Gaussian noise which behaves as a Wiener process in space and the time covariance generates a signed measure. This class includes the Brownian motion, fractional Brownian motion and other related processes. We give a necessary and sufficient condition for the existence of the solution and we study the path regularity of this solution. 相似文献
20.
Mounir Afilal 《Applicable analysis》2013,92(3):638-650
In this paper, we consider a linear damped porous thermoelastic system of memory type where the heat conduction is given by Cattaneo’s Law . We establish a general decay results using an appropriate Lyapunov functional. 相似文献