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21.
Etienne P. Hessou Lucie A. Bd Hicham Jabraoui Abderrahmane Semmeq Michael Badawi Valentin Valtchev 《Molecules (Basel, Switzerland)》2021,26(18)
In this study, density functional theory (DFT) calculations have been performed to investigate the adsorption mechanisms of toluene and water onto various cationic forms of Y zeolite (LiY, NaY, KY, CsY, CuY and AgY). Our computational investigation revealed that toluene is mainly adsorbed via π–interactions on alkalis exchanged Y zeolites, where the adsorbed toluene moiety interacts with a single cation for all cases with the exception of CsY, where two cations can simultaneously contribute to the adsorption of the toluene, hence leading to the highest interaction observed among the series. Furthermore, we find that the interaction energies of toluene increase while moving down in the alkaline series where interaction energies are 87.8, 105.5, 97.8, and 114.4 kJ/mol for LiY, NaY, KY and CsY, respectively. For zeolites based on transition metals (CuY and AgY), our calculations reveal a different adsorption mode where only one cation interacts with toluene through two carbon atoms of the aromatic ring with interaction energies of 147.0 and 131.5 kJ/mol for CuY and AgY, respectively. More importantly, we show that water presents no inhibitory effect on the adsorption of toluene, where interaction energies of this latter were 10 kJ/mol (LiY) to 47 kJ/mol (CsY) higher than those of water. Our results point out that LiY would be less efficient for the toluene/water separation while CuY, AgY and CsY would be the ideal candidates for this application. 相似文献
22.
Abderrahmane Nitaj 《计算数学(英文版)》2002,20(4):337-348
AbstractAn elliptic curve is a pair (E,O), where ?is a smooth projective curve of genus 1 and O is a point of E, called the point at infinity. Every elliptic curve can be given by a Weierstrass equationE:y2 a1xy a3y = x3 a2x2 a4x a6.Let Q be the set of rationals. E is said to be dinned over Q if the coefficients ai, i = 1,2,3,4,6 are rationals and O is defined over Q.Let E/Q be an elliptic curve and let E(Q)tors be the torsion group of points of E denned over Q. The theorem of Mazur asserts that E(Q)tors is one of the following 15 groupsE(Q)tors Z/mZ, m = 1,2,..., 10,12,Z/2Z × Z/2mZ, m = 1,2,3,4.We say that an elliptic curve E'/Q is isogenous to the elliptic curve E if there is an isogeny, i.e. a morphism : E E' such that (O) = O, where O is the point at infinity.We give an explicit model of all elliptic curves for which E(Q)tors is in the form Z/mZ where m= 9,10,12 or Z/2Z × Z/2mZ where m = 4, according to Mazur's theorem. Morever, for every family of such elliptic curves, we give an explicit m 相似文献
23.
24.
Abdel-Nour Zaim Aissa Abderrahmane Mebarek-Oudina Fateh Rashad A. M. Ali Hafiz Muhammad Sahnoun M. El Ganaoui M. 《Journal of Thermal Analysis and Calorimetry》2020,141(5):1981-1992
Journal of Thermal Analysis and Calorimetry - The effect on the entropy production and MHD convection of the hybrid nanofluid Al2O3–Cu/water (water with Cu and Al2O3 nanoparticles) in a... 相似文献
25.
We address the classification problem where an item is declared to be from populationπjif certain of its characteristicsvare assumed to be sampled from the distribution with pdf fj(vθj), wherej=1, 2, …, m. We first solve the two population classification problem and then extend the results to the generalmpopulation classification problem. Usually only the form of the pdf's is known. To use the classical classification rule the parameters,θj, must be replaced by their estimates. In this paper we allow the parameters of the underlying distributions to be generated from prior distributions. With this added structure, we obtain Bayes rules based on predictive distributions and these are completely determined. Using the first-order expansion of the predictive density, where the coefficients of powers ofn−1remain uniformly bounded innwhen integrated, we obtain an asymptotic bound for the Bayes risk. 相似文献
26.
Abdallah Zeineddine Dr. Feriel Rekhroukh Dr. E. Daiann Sosa Carrizo Sonia Mallet‐Ladeira Dr. Karinne Miqueu Dr. Abderrahmane Amgoune Dr. Didier Bourissou 《Angewandte Chemie (International ed. in English)》2018,57(5):1306-1310
The [(P,P)Au=C(Ph)CO2Et]+ complex 3 [where (P,P) is an o‐carboranyl diphosphine ligand] was prepared by diazo decomposition at ?40 °C. It is the first α‐oxo gold carbene complex to be characterized. Its crystallographic structure was determined and DFT calculations have been performed, unraveling the key influence of the chelating (P,P) ligand. The gold center is tricoordinate and the electrophilicity of the carbene center is decreased. Complex 3 mimics transient α‐oxo gold carbenes in a series of catalytic transformations, and provides support for the critical role of electrophilicity in the chemoselectivity of phenol functionalization (O?H vs. C?H insertion). 相似文献
27.
Smaail Radi Abderrahmane Yahyi Abdelkrim Ramdani Ismail Zidane Brahim Hacht 《Tetrahedron》2006,62(39):9153-9155
The synthesis of a new tetrapyrazolic macrocyclic structure with a functionalised arm is described. The complexing properties of this new compound towards alkali metal ions (K+, Na+, Li+) were studied by liquid-liquid extraction and liquid membrane transport processes. The extracted and the transport cation percentage were determined by atomic absorption measurements and UV spectroscopy. 相似文献
28.
We consider two overlapping generations that want to coordinate their strategies of working, consuming and controlling pollution. Since the cooperative solution is not an equilibrium, and hence is not a self-enforcing contract, a mechanism is required to sustain it. We show how incentive strategies, and the resulting incentive equilibrium, could provide such a mechanism. We also derive the conditions that ensure the credibility of these strategies. 相似文献
29.
Ralitsa Chimshirova Milena Popova Amina Chakir Violeta Valcheva Simeon Dimitrov Boryana Trusheva Abderrahmane Romane Vassya Bankova 《Molecules (Basel, Switzerland)》2022,27(7)
The chemical composition and antimicrobial activity of propolis from a semi-arid region of Morocco were investigated. Fifteen compounds, including triterpenoids (1, 2, 7–12), macrocyclic diterpenes of ingol type (3–6) and aromatic derivatives (13–15), were isolated by various chromatographic methods. Their structures were elucidated by a combination of spectroscopic and chiroptical methods. Compounds 1 and 3 are new natural compounds, and 2, 4–6, and 9–11 are newly isolated from propolis. Moreover, the full nuclear magnetic resonance (NMR) assignments of three of the known compounds (2, 4 and 5) were reported for the first time. Most of the compounds tested, especially the diterpenes 3, 4, and 6, exhibited very good activity against different strains of bacteria and fungi. Compound 3 showed the strongest activity with minimum inhibitory concentrations (MICs) in the range of 4–64 µg/mL. The combination of isolated triterpenoids and ingol diterpenes was found to be characteristic for Euphorbia spp., and Euphorbia officinarum subsp. echinus could be suggested as a probable and new plant source of propolis. 相似文献
30.
Maher Boudabra Abderrahmane Nitaj 《Journal of Applied Mathematics and Computing》2018,57(1-2):229-245
The KMOV scheme is a public key cryptosystem based on an RSA modulus \(n=pq\) where p and q are large prime numbers with \(p\equiv q\equiv 2\pmod 3\). It uses the points of an elliptic curve with equation \(y^2\equiv x^3+b\pmod n\). In this paper, we propose a generalization of the KMOV cryptosystem with a prime power modulus of the form \(n=p^{r}q^{s}\) and study its resistance to the known attacks. 相似文献