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91.
A. El-Gohary Ahmad Alshamrani Adel Naif Al-Otaibi 《Applied Mathematical Modelling》2013,37(1-2):13-24
This paper deals with a new generalization of the exponential, Gompertz, and generalized exponential distributions. This distribution is called the generalized Gompertz distribution (GGD). The main advantage of this new distribution is that it has increasing or constant or decreasing or bathtub curve failure rate depending upon the shape parameter. This property makes GGD is very useful in survival analysis. Some statistical properties such as moments, mode, and quantiles are derived. The failure rate function is also derived. The maximum likelihood estimators of the parameters are derived using a simulations study. Real data set is used to determine whether the GGD is better than other well-known distributions in modeling lifetime data or not. 相似文献
92.
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94.
In this paper, we find a reasonable explanation of high temperature superconductivity phenomena using Anyon statistics.
相似文献95.
Ezzat Hany G. Bayoumi Ashraf H. Sherbiny Farag F. El-Morsy Ahmed M. Ghiaty Adel Alswah Mohamed Abulkhair Hamada S. 《Molecular diversity》2021,25(1):291-306
Molecular Diversity - Many shreds of evidence have recently correlated A2B receptor antagonism with anticancer activity. Hence, the search for an efficient A2B antagonist may help in the... 相似文献
96.
97.
Taha M. A. Eldebss Ahmad M. Farag Adel Y. M. Shamy 《Journal of heterocyclic chemistry》2019,56(2):371-390
A series of new substituted benzimidazoles embedded with a variety of function groups has been synthesized from N‐methyl‐2‐bromoacetylbenzimidazole. The synthesized compounds were fully characterized, and their structures were elucidated based on elemental analysis, spectral data, and alternative synthetic pathways, whenever possible. Some of benzimidazole derivatives were tested as corrosion inhibitors. 相似文献
98.
Ibtissem Lounas Hanane Zazoua Adel Saadi Zahia Mesbah Benyoucef 《Research on Chemical Intermediates》2018,44(11):6549-6567
Supported copper catalysts on low surface area silica were prepared by several methods and characterized by AAS, XRD, N2 adsorption, SEM, H2-TPR, N2O titration, TGA-DTA, UV–Vis techniques. Their hydrogenating properties were examined in the gas-phase hydrogenation of benzaldehyde. The analysis of characterization results revealed that the choice of preparation method affected the texture, composition, and structure of the calcined and reduced Cu/SiO2 catalysts. The dispersion and size distribution of copper species was present in different forms in the catalysts that exhibited low specific surface areas. In gas-phase hydrogenation of benzaldehyde to benzyl alcohol, the catalysts tested at the reaction temperatures of 160 and 200 °C were stable and conducted to a good catalytic activity and benzyl alcohol selectivity ranging between 5 and 39 µmol min?1 g?1 and 0–95%, respectively. The activity of the catalysts in gas-phase hydrogenation also depended on the particle size and the nature of copper species formed on low surface area silica. 相似文献
99.
Kuramshin A. I. Plotnikova A. V. Adel’shina M. V. Galkin V. I. 《Russian Journal of Organic Chemistry》2018,54(11):1746-1748
Russian Journal of Organic Chemistry - The coupling of dimethyl phosphite and iodobenzene occurs in the presence of catalytic amounts of homoligand carbonyl complexes of chromium subgroup metals to... 相似文献
100.
Emara AA El-Sayed BA Ahmed el-SA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(3):757-769
4,6-Diacetylresorcinol (DAR) serves as precursor for the formation of different hydrazone ligands, which are di-, tetra- or hexa-basic with two symmetrical sets of O(2)N tridentate, O(2)N(2) tetradentate or O(4)N(2) hexadentate chelating sites. The condensation of 4,6-diacetylresorcinol (DAR) with oxalyldihydrazine (ODH), in the molar ratio 1:1 and 1:2, yields the corresponding hydrazone, H(6)L(a) and H(4)L(b), ligands, respectively. The structures of these ligands were elucidated by elemental analyses and IR, mass, (1)H NMR and UV-vis spectra. Reactions of the hydrazone ligands with cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), iron(III) and chromium(III) ions in 1:2 molar ratio afforded the corresponding transition metal complexes. A variety of binuclear transition metal complexes were obtained in its di-, tetra- or hexa-deprotonated forms. The structures of the newly prepared complexes were identified by elemental analyses and IR, UV-vis, mass, (1)H NMR and ESR spectra, as well as, magnetic susceptibility measurements and thermal gravimetric analysis (TGA). The bonding sites are the azomethine and CO oxygen atoms in either keto or enol forms and amino nitrogen atoms, and phenolic oxygen atoms. The metal complexes exhibit different geometrical structures such as tetrahedral and octahedral arrangements. 相似文献