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Lgaz Hassane Chaouiki Abdelkarim Albayati Mustafa R. Salghi Rachid El Aoufir Yasmina Ali Ismat H. Khan Mohammad I. Mohamed Shaaban K. Chung Ill-Min 《Research on Chemical Intermediates》2019,45(4):2269-2286
Research on Chemical Intermediates - Mild steel corrosion in HCl solution is an example of corrosion in acidic mediums. The ongoing research efforts to develop novel environmentally friendly... 相似文献
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Rabab Boyaala Rafika El Ati Mohamed Khoutoul Mohamed El Kodadi Rachid Touzani Belkheir Hammouti 《Journal of the Iranian Chemical Society》2018,15(1):85-92
In the present work, catecholase activity is presented. The complexes were prepared by condensation of the organic ligand pyrazolyl L 1 –L 4 and copper(II) ion in situ. The pyrazolyl compounds L 1 –L 4 used in this study are: L 1 is (3,5-dimethyl-pyrazol-1-ylmethyl)-(4-methyl-pyridin-2-yl)-pyrazol-1-ylmethyl-amine; L 2 is 1-{4-[(3,5-dimethyl-pyrazol-1-ylmethyl)-pyrazol-1-ylmethyl-amino]-phenyl}-ethanone; L 3 is 1-{4-[(3,5-dimethyl-pyrazol-1-ylmethyl)-[1,2,4]triazol-1-ylmethyl-amino]-phenyl}-ethanone, and L 4 is 2-[(3,5-dimethyl-pyrazol-1-ylmethyl)-[1,2,4]triazol-1-ylmethyl-amino]-6-methyl-pyrimidin-4-ol, and copper ions salts Cu(II) are (Cu(CH3COO)2, CuCl2, Cu(NO3)2 and CuSO4). In order to determine factors influencing the catecholase activity of these complexes, the effect of ligand nature, ligand concentration, nature of solvent and nature of counter anion has been studied. The best activity of catechol oxidation is given by the combination formed by one equivalent of ligand L 2 and one equivalent of Cu(CH3COO)2 in methanol solvent which is equal to 9.09 µmol L?1 min?1. The Michaelis–Menten model is applied for the best combination, to obtain the kinetic parameters, and we proposed the mechanism for oxidation reaction of catecholase. 相似文献
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Henri-Joël Sedjame Rachid Brahmi Gwendoline Lafaye Jacques Barbier Céline Fontaine 《Comptes Rendus Chimie》2018,21(3-4):182-193
Monolithic catalysts are prepared by washcoating cordierite monoliths with different sols (Pt/Al2O3, Pt/CeO2, Pt/ZrO2, Pt/Al2O3CeO2, Pt/Al2O3ZrO2, and Pt/CeO2ZrO2). These sols are prepared by a sol–gel process and characterized by specific surface area (SBET), inductively coupled plasma, hydrogen chemisorption, high-resolution transmission electron microscopy, field emission scanning electron microscopy, oxygen storage capacity, X-ray diffraction, temperature-programmed reduction, CO2 chemisorption, and the model reaction of 3,3-dimethylbutene isomerization. The catalytic performances of the monolithic catalysts are then evaluated for the acetic acid oxidation. The nature of catalyst coating has been found to influence the adherence with the cordierite monolith and the presence of cerium in the catalyst appears to increase the adherence of the latter. Pt/CeO2, Pt/Al2O3CeO2, and Pt/CeO2ZrO2 are found to be the most reducible catalysts (oxygen storage capacity and temperature-programmed reduction) and to have the lowest acidities (3,3-dimethylbutene isomerization). CO2 chemisorption shows that these catalysts possess a good basicity. From the relation established between the catalytic activity and the redox and acid–base properties it has been concluded that the reducibility is the key factor for a good catalytic activity although the basicity has a significant influence on the catalytic performance. 相似文献
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Matmour R De Cat I George SJ Adriaens W Leclère P Bomans PH Sommerdijk NA Gielen JC Christianen PC Heldens JT van Hest JC Löwik DW De Feyter S Meijer EW Schenning AP 《Journal of the American Chemical Society》2008,130(44):14576-14583
Two oligo(p-phenylenevinylene)-peptide hybrid amphiphiles have been synthesized using solid- and liquid-phase strategies. The amphiliphiles are composed of a pi-conjugated oligo(p-phenylenevinylene) trimer (OPV) which is coupled at either a glycinyl-alanyl-glycinyl-alanyl-glycine (GAGAG) silk-inspired beta-sheet or a glycinyl-alanyl-asparagyl-prolyl-asparagy-alanyl-alanyl-glycine (GANPNAAG) beta-turn forming oligopeptide sequence. The solid-phase strategy enables one to use longer peptides if strong acidic conditions are avoided, whereas the solution-phase coupling gives better yields. The study of the two-dimensional (2D) self-assembly of OPV-GAGAG by scanning tunneling microscopy (STM) at the submolecular level demonstrated the formation of bilayers in which the molecules are lying antiparallel in a beta-sheet conformation. In the case of OPV-GANPNAAG self-assembled monolayers could not be observed. Absorption, fluorescence, and circular dichroism studies showed that OPV-GAGAG and OPV-GANPNAAG are aggregated in a variety of organic solvents. In water cryogenic temperature transmission electron microscopy (cryo-TEM), atomic force microscopy (AFM), light scattering, and optical studies reveal that self-assembled nanofibers are formed in which the helical organization of the OPV segments is dictated by the peptide sequence. 相似文献
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The mixture {yNH4Cl + (1 − y)MgCl2} (aq) has been studied using the hygrometric method at the temperature 298.15 K. The water activities are measured at total molalities from 0.30 mol kg−1 up to saturation for different ionic strength fractions y of NH4Cl with y = 0.20, 0.50 and 0.80. The obtained data allow the deduction of osmotic coefficients. Experimental results are compared with the calculations using the models of Zdanovskii–Stokes–Robinson, Kusik and Meissner, Robinson and Stokes, Lietzke and Stoughton, Reilly–Wood and Robinson and Pitzer. Thermodynamic properties have been modeled using the Pitzer ion-interaction model with inclusion of an ionic strength dependence of the third virial coefficient for the binary systems. From these measurements and the obtained binary parameters β(0), β(1), C(0) and C(1), the mixing ionic parameters θNH4Mg and ψNH4MgCl are determined by the standard Pitzer model. The results show that a good accuracy is obtained with the standard Pitzer model using extended binary parameters. The parameters θNH4Mg and ψNH4MgCl were used for evaluation of activity coefficients in the mixture. The excess Gibbs energy is also determined. 相似文献
69.
Sunto In questa Nota, si affronta il problema del comportamento asintotico nel tempo di perturbazioni alla quiete per il sistema
di equazioni per un fluido comprimibile, viscoso e politropico. Ammesso che esista una soluzione regolare globale, si dimostra,
sotto l’ipotesi che il gradiente della temperatura assegnata al bordo sia piccolo, che la differenza tra la soluzione corrispondente
a dati iniziali arbitrari e la quiete decade a zero pert che tende ad infinito nella normal diL
2.
The second author thanks the 60% contract MURST, also she acknowledges the GNFM of italian CNR-INDAM for financial supports. 相似文献
We consider the equation system for a compressible viscous polytropic fluid in a regualar bounded domain and we study the asymptotic behavior as time goes to infinity of perturbations with respect to the basic rest state. Under the assumption of the smallness of the gradient of the given temperature on the boundary, we prove the exponential decay of theL 2-norm of the difference between the solution corresponding to arbitrary initial data and the rest state.
The second author thanks the 60% contract MURST, also she acknowledges the GNFM of italian CNR-INDAM for financial supports. 相似文献
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