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On stability behaviors of 5D M-theory black objects

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Communications in Theoretical Physics 2024年第5期76卷 94-101页

作者： Adil Belhaj Abderrahim Bouhouch departement de Physique Equipe des Sciences de la matiere et du rayonnementESMaR Faculte des SciencesUniversite Mohammed V de RabatRabatMorocco

Using N=2 supergravity formalism,we investigate certain behaviors of five-dimensional black objects from the compactification of M-theory on a Calabi-Yau *** manifold has been constructed as the intersection of two homogeneous polynomials of degrees(ω+2,1)and(2,1)in a product of two weighted projective spaces given by WP^(4)(ω,1,1,1,1)×P^(1).First,we determine the allowed electric charge regions of the BPS and non BPS black holes obtained by wrapping M2-branes on appropriate two cycles in such a proposed Calabi-Yau *** that,we calculate the entropy of these solutions which takes a maximal value corresponding to ω=1 defining the ordinary projective space P^(4).For generic values of ω,we show that the non BPS states are ***,we conduct a similar study of five-dimensional black *** the allowed magnetic charge regions of the BPS and non BPS black stringy solutions derived from M5-branes on dual divisors,we calculate the tension taking a minimal value for P^(4).By determining the recombination factor,we show that the non-BPS black string states are stable in the allowed regions in the magnetic charge space.

关键词： M-theory Calabi-Yau manifolds black holes black strings stability behaviors

Synthesis of Some New 1,4-Dihydropyridine derivatives through a Facile One-pot Hantzsch Condensation Catalyzed by Triethylamine

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Chinese Journal of Chemistry 2012年第3期30卷 733-737页

作者： Ghalem, Wassima Boulcina, Raouf debache, Abdelmadjid Laboratoire de Synthese des Molecules d＇Interet Biologique Departement de ChimieFaculte des Sciences Exactes Universite Mentouri de Constantine 25000 Constantine Algerie

A facile and efficient synthesis of new 1,4-dihydropyridine derivatives was reported via Hantzsch three-com- ponent condensation reaction of aldehydes or formylphenylboronic acids, ethyl acetoacetate, and ammonium acetate in the presence of a catalytic amount of triethylamine under solvent-free conditions. The method described here of- fers several advantages including high yields, short reaction times, and simple work-up procedure.

关键词： 1,4-dihydropyridine triethylamine formylphenylboronic acid Hantzsch reaction solvent-flee condi-tion

density Functional Theory Study on Interaction between Catechin and Thymine

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Chinese Journal of Chemical Physics 2012年第6期25卷 642-648,I0003页

作者： Wan-fei Cai Yan Zheng Lai-cai Li An-min Tian departement of Chemistry and Material Science Sichuan Normal University Chengdu 510065China departement of Chemistry Sichuan University Chengdu 510054 China

The interacting patterns and mechanism of the catechin and thymine have been investigated with the density functional theory Becke＇s three-parameter nonlocal exchange functional and the Lee, Yang, and Parr nonlocal correlation functional （B3LYP） method by 6-31＋G＊ basis set. Thirteen stable structures for the catechin-thymine complexes have been found which form two hydrogen bonds at least. The vibrational frequencies are also studied at the same level to analyze these complexes. The results indicated that catechin interacted with thynfine by three different hydrogen bonds as N-H…O, C-H…O, O-H…O and the complexes are mainly stabilized by the hydrogen bonding interactions. Theories of atoms in molecules and natural bond orbital have been adopted to investigate the hydrogen bonds involved in all systems. The interaction energies of all complexes have been corrected for basis set superposition error, which are from -18.15 k J/mol to -32.99 kJ/mol. The results showed that the hydrogen bonding contribute to the interaction energies dominantly. The corresponding bonds stretching motions in all complexes are red-shifted relative to that of the inonomer, which is in agreement with experimental results.

关键词： density functional theory Thymine Hydrogen bond Catechin

HALOMETHYLATION OF POLYSTYRENE AND SUBSEQUENT PYRIDINATION VIA A HOMOLYTIC PATHWAY

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Chinese Journal of Polymer Science 2006年第6期24卷 627-635页

作者： Sad Moulay Nadia Mehdi Laboratoire de Chimie-Physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Departement de Chimie IndustrielleUniversité de BlidaRoute de SoumaB. P. 270Blida 09000Algeria

Chloromethylation of polystyrene （PS） with two different chloromethylating systems methylal/thionyl chloride and paraformaldehyde/trimethylchlorosilane was studied. Soluble chloromethylated polystyrene with a degree of substitution of 89% was obtained. The Conant-Finkelstein reaction on the chloromethylated PS afforded soluble iodomethylated polystyrene with a degree of substitution as high as 96%. The reaction conditions of Minisci were employed to radically pyridinate PS via its iodomethylated derivative. Polyelectrolytes were formed which could be converted to normal polymers by treatment with a 20% aqueous solution of NaOH.

关键词： Chloromethylated polystyrene Conditions of Minisci Iodomethylated polystyrene Pyridinated polystyrene.

Mechanical and Abrasive Wear Properties of Anodic Oxide Layers Formed on Aluminium

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Journal of Materials Science & Technology 2009年第4期25卷 508-512页

作者： W. Bensalah K. Elleuch M. Feki M. Wery H.F. Ayedi Unit'e de Recherche de Chimie Industrielle et Mat'eriaux(URCIM) Departement of Materials EngineeringNational School of Engineering IUT Orsay-Paris XI University

Aluminium oxide coatings were formed on aluminium substrates in oxalic acid-sulphuric acid bath. Abrasion tests of the obtained anodic layers were carried out on a pin-on-disc machine in accordance with the ISO/DP 825 specifications. The rickets microhardness, D （HV0.2）, and the abrasion weight loss, Wa （mg） were measured. Influence of oxalic acid concentration （Cox）, bath temperature （T） and anodic current density （J） on D and Wa has been examined, and the sulphuric acid concentration （Csul） was maintained at 100 g.L-1. It was found that high microhardness and abrasive wear resistance of oxide layers were produced under low temperatures and high current densities with the addition of oxalic acid. The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy （SEM）, atomic force microscopy （AFM）, optical microscopy and glow-discharge optical emission spectroscopy （GDOES）. It was found that the chemistry of the anodizing electrolyte, temperature, and current density are the controlling factors of the mechanical properties of the anodic oxide layer.

关键词： Aluminium oxide Vickers microhardness Abrasive wear

THERMOSENSITIVE SUPERABSORBENTS BASED ON POLY(N,N-DIETHYLACRYL AMIde-co-SODIUM ACRYLATE)

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Chinese Journal of Polymer Science 2012年第6期30卷 873-878页

作者： D.G.Lessard 朱晓夏 departement de Chimie Universite de MontrealC.P.6128 Succursale Centre-ville MontrealQCH3C 3J7Canada

A series of poly（N,N-diethylacrylamide-co-sodium acrylate） with a degree of crosslinking of 1 mol% have been prepared as therrnosensitive superabsorbents for water. The critical swelling temperatures or the volume phase transition temperature （VPTT） and the water absorption capacity of the polymers can be modulated by varying the amount of sodium acrylate （0-60 tool%） in the copolymers. The water absorption and swelling properties of the different hydrogels have been studied as function of temperature. The crosslinked copolymers can absorb large amounts of water at ambient temperatures and dehydrate at higher temperatures with relative ease, making the absorbent materials thermally responsive and thus reusable. The water absorption capacity of the copolymers depends on the pH of the media as the acrylate monomer has a higher water absorption in its deprotonated state. Added urea in the media raises and sharpens the VPTT values of the copolymers containing sodium acrylate.

关键词： Thermosentive polymers Superabsorbents Hydrogels Swelling Poly(N,N-diethylacrylamide-co-sodiumacrylate).

RING OPENING POLYMERIZATION OF TETRAHYDROFURAN CATALYSED BY MAGHNITE-H^+

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Chinese Journal of Polymer Science 2012年第1期30卷 56-62页

作者： Khadidja Benkenfoud Amine Harrane Mohammed Belbachir Laboratoire de Chimie des Polymeres departement de Chimie Faculte des SciencesUniversite d'Oran Es-SeniaBP No 1524 El M'Naouar31000 OranAlgeria

The cationic ring-opening polymerization of tetrahydrofiiran using maghnite-H~＋ is ***-H~＋,is a non-toxic solid catalyst issued from proton exchanged montmorillonite ***,also called ＂poly（butandiol） ether＂,with acetate and hydroxyl end groups was successfully *** of reaction temperature, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated.A cationic mechanism of the reaction was *** chemistry can be considered as a suitable route for preparing poly（THF） as a soft segment for thermoplastic elastomers.

关键词： Montmorillonite Maghnite Ring opening polymerization THF

Advancing healthcare through laboratory on a chip technology:Transforming microorganism identification and diagnostics

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World Journal of Clinical Cases 2025年第3期13卷 9-19页

作者： Carlos M Ardila department of Basic Sciences Biomedical Stomatology Research GroupUniversidad de Antioquia U de AMedellín 0057Colombia

In a recent case report in the World Journal of Clinical Cases,emphasized the crucial role of rapidly and accurately identifying pathogens to optimize patient treatment ***-on-a-chip(LOC)technology has emerged as a transformative tool in health care,offering rapid,sensitive,and specific identification of *** editorial provides a comprehensive overview of LOC technology,highlighting its principles,advantages,applications,challenges,and future *** studies from the field have demonstrated the practical benefits of LOC devices in clinical diagnostics,epidemiology,and food *** studies have underscored the superiority of LOC technology over traditional methods,showcasing improvements in speed,accuracy,and *** future integration of LOC with biosensors,artificial intelligence,and data analytics promises further innovation and *** call to action emphasizes the importance of continued research,investment,and adoption to realize the full potential of LOC technology in improving healthcare outcomes worldwide.

关键词： Laboratory-on-a-chip Microorganism identification Diagnostics Point-ofcare testing Biosensors

Photoresponse and H2 gas sensing properties of highly oriented Al and Al/Sb doped ZnO thin films

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Progress in Natural Science:Materials International 2013年第6期23卷 519-523页

作者： Hannane Benelmadjat Boubekeur Boudine Aissa Keffous Noureddine Gabouze Laboratoire de Physico-Chimie des Semi-Conducteurs Departement de PhysiqueFaculte des Sciences ExactesUniversite Mentouri-Route Ain Elbey Laboratoire de Cristallographie Departement de PhysiqueFaculte des Sciences ExactesUniversite Mentouri-Route Ain Elbey Silicon Technology development Unit

ZnO:Al and ZnO:Al/Sb thin films have been prepared and *** thin films were deposited on Si substrates by the sol-gel *** structural,optical and electrical properties of ZnO films have been investigated by spectrophotometry,ellipsometry,X-ray diffraction and current-voltage *** is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate,a high reflectivity in the infrared region and a response to ***,it has been found that Si/（ZnO:Al/Sb）/Al photodiode is promising in photoconduction device while Si/（ZnO:Al）/Al can be used as gas sensor responding to the low H2concentrations.

关键词： Zinc oxide Co-doping Thin films Gas sensing Photoresponse