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71.
A. N. Tawfik A. M. Diab M. T. Hussein 《Journal of Experimental and Theoretical Physics》2018,126(5):620-632
The linear-sigma model, in which information about confining gluons is included through the Polyakov-loop potential (PLSM), is considered in order to perform a systematic study for various magnetic properties of QCD matter under extreme conditions of high temperatures and densities and finite magnetic field strengths. The introduction of magnetic field to the PLSM Lagrangian requires suitable utilization of Landau quantization, modification in the dispersion relations, and momentum-space dimension-reduction. We observed that increasing the magnetic field leads to filling-up lower Landau levels first and decreasing the number of occupied levels. We conclude that the population of Landau levels is most sensitive to the magnetic field and to the quark charges. The influences of finite magnetic field on the temperature dependence of chiral and deconfinement order-parameter(s) are studied. We present estimations for the magnetization, the magnetic susceptibility, the permeability, and the catalytic properties of QCD matter as functions of temperature. The dependences of the resulting freeze-out parameters, temperatures, and baryon chemical potentials on the corresponding magnetic field strengths have been analyzed, as well. These calculations are compared with recent lattice QCD simulations, whenever available. We conclude that the QCD matter seems to have paramagnetic property at temperatures greater than the critical one. There is an evidence for weak diamagnetic property at low temperatures. Last but not least, we observe that the magnetic catalysis is inverse, namely, the critical temperatures decrease with increasing the magnetic field. 相似文献
72.
73.
Belaïd Diab Henri Jolibois Bernard Laude Stphane Golhen Lahcne Ouahab Alain Chambaudet 《Helvetica chimica acta》1999,82(5):779-789
One-Step Synthesis of Novel Heptacyclic Molecules Starting from 2-Aryl-4-methyl-1-benzopyrylium Salts. X-Ray Crystal Structures of These Compounds Containing a Methano-Bridged 1-Benzoxepine Fused to Two 1-Benzopyran Moieties The chemical reduction of 4-methyl-2-(ortho-hydroxyaryl)-1-benzopyrylium chlorides with Zn in MeCN and HCl led to a mixture of diastereoisomeric heptacyclic molecules. The structures of two of them were determined by X-ray analysis. These methano-bridged 1-benzoxepines fused to two 1-benzopyran moieties were formed from intermediate biflavene species. 相似文献
74.
75.
Buncha Pulpoka Zouhair Asfari Jacques Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》1997,27(1):21-30
Co-receptor 1,3-calix[4]-di(aza-benzo)crown-crown-6 (1-H) designed with one calix[4]arene in a 1,3-alternate conformation and hard and soft metal ion binding sites has been prepared according to three pathways (A-C). Pathway B, consisting of two different 1 + 1 condensations with ditosylate derivatives, was shown to be the most efficient. 相似文献
76.
Oni J Pailleret A Isik S Diab N Radtke I Blöchl A Jackson M Bedioui F Schuhmann W 《Analytical and bioanalytical chemistry》2004,378(6):1594-1600
In a preliminary study aimed at developing strategies for the simultaneous detection of various biologically important molecules, a procedure is described that allows the electrochemical detection of nitric oxide (NO) released by a population of human umbilical vein endothelial cells (HUVEC) by using an array of electrodes comprising three individually addressable electrodes. Each electrode in the array was modified with a different NO-sensitive electrocatalyst, thereby demonstrating the possibility of modifying the individual electrodes in an array with different sensing chemistries. This study opens a doorway to the development of arrays of electrodes for the simultaneous detection of multiple analytes in a complex environment by suitably tailoring the sensitivity and selectivity of each electrode in the array to a specific analyte in the test medium. 相似文献
77.
Zouhair Asfari Sebastiano Pappalardo J. Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》1992,14(2):189-192
A doubly-crowned calix and a double-calixcrown derived from 4,6,10,12,16,18,22,24,25,26,27, 28-dodecamethyl-5,11,17, 23-tetrahydroxycalix[4]arene (1) have been prepared by reaction of appropriate oligoethylene glycol ditosylates with (1) in acetonitrile in the presence of potassium carbonate. A potassium template effect is observed during one of the double cyclizations. 相似文献
78.
M. A. Diab 《Journal of polymer science. Part A, Polymer chemistry》1983,21(11):3249-3256
The thermal stability of PVB and five VB-MA copolymers with different compositions was studied by thermogravimetric analysis in dynamic nitrogen. The reactivity ratios of the copolymers were determined by using NMR techniques. It was found that r1(VB) = 0.5 ± 0.1 and r2(MA) = 7.3 ± 0.3. The stability of VB increases as the MA concentration in the copolymer compositions increases. Apparently, the formation of lactone and anhydride structures has a stabilizing effect. The stability imparted to the degrading copolymers by lactone and anhydride structures is insufficient to produce stability comparable to that of PMA itself. 相似文献
79.
The reactions of Grignard reagents with α-keto oximes 1 and α-hydroximino alcohols 3, give secondary aziridine alcohols 2 or 4, which with SOCL2 (or COCl2)give azabicyclo[3.1.0]oxo-2 oxaisothiazolidine-1, 5 or azabicyclo[3.1.0]carbamate-1,2,3 6. The determination of configuration of 2,4 and 5 was achieved by an NOE study. 相似文献
80.
The thermal stabilities of poly(-bromostyrene), poly-(methyl methacrylate) homopolymers and copolymers of-bromostyrene-methyl methacrylate covering the entire composition range were studied using TG analysis. At each extreme of the composition range, incorporation of comonomer units results in a copolymer more stable than the brominated homopolymer. Maximum stability occurs for compositions of approximately 62 mole percent-bromostyrene. The formation of the anhydride structure among the degradation products leads to the stability of the copolymers.
Presented at the World Conference of Thermal Analysis, held in Bad Hofgastein (Austria), 1985. 相似文献
Zusammenfassung Die thermische Stabilität von-Bromstyrol- und Methylmethacrylat-Homopolymeren sowie von sich über den ganzen Zusammensetzungsbereich erstreckenden-Bromstyrol/Methylmethacrylat-Kopolymeren wurde thermogravimetrisch untersucht. An beiden Enden des Zusammensetzungsbereichs führt der Einbau von Komonomereinheiten zu einem Kopolymer, das stabiler als das bromierte Homopolymer ist. Maximale Stabilität wird bei einem Gehalt von etwa 62 Mol-%-Bromstyrol erreicht. Die Bildung der Anhydridstruktur führt zur Stabilität des Kopolymers.
/-, - . , . - 62%. .
Presented at the World Conference of Thermal Analysis, held in Bad Hofgastein (Austria), 1985. 相似文献