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141.
Pham Sy Hieu Pham Minh Doan Sane Abdoul Razac Nguyen Xuan Hoan Semlal Nawal Boulif Rachid Germeau Alain Toussaint Claudia Sharrock Patrick Nzihou Ange 《Journal of Thermal Analysis and Calorimetry》2021,146(5):2027-2033
Journal of Thermal Analysis and Calorimetry - Up-to-date, solar salt (a mixture of 60 mass% NaNO3 and 40 mass% KNO3) is practically the only media for thermal energy storage (TES) in concentrated... 相似文献
142.
Tapia R Guardia JJ Alvarez E Haidöur A Ramos JM Alvarez-Manzaneda R Chahboun R Alvarez-Manzaneda E 《The Journal of organic chemistry》2012,77(1):573-584
A new strategy for synthesizing taiwaniaquinoids, a group of terpenoids with an unusual rearranged 5(6→7) or 6-nor-5(6→7)abeo-abietane skeleton, which exhibit promising biological activities, is reported. The procedure, based on the cleavage of the C7-C8 double bond of abietane diterpenes, is the only one yet reported for synthesizing C(20) taiwaniaquinoids bearing a carbon function on the cyclopentane B ring; it is also applicable to the synthesis of the wide variety of existing taiwaniaquinoids. Utilizing this, (-)-taiwaniaquinone A, F, G, and H, (-)-taiwaniaquinol B, and (-)-dichroanone have been synthesized from (+)-abietic acid. The versatility of this strategy allows us to propose the abietane C7-C8 cleavage as a possible biosynthetic pathway to this type of rearranged diterpenes; this proposal seems to be supported by phytochemical evidence. 相似文献
143.
A new derivative of the strained 3,3,6,6-tetramethylthiacycloheptyne (TMTH) bearing a functional handle is reported. Following an optimized synthesis, the handle was introduced by mild alkylation of the sulphur atom. The resulting functionalized strained 4,5-didehydro-3,3,6,6-tetramethyl-2,3,6,7-tetrahydrothiepinium (TMTI) proved to be stable and underwent extremely fast [3+2] cycloaddition reaction with benzyl azide in both organic and aqueous solvents. The reaction was equally efficient in cell lysate and serum and therefore opens interesting prospects for chemical-biology applications. 相似文献
144.
Rachid Essehli Brahim El Bali Aziz Alaoui Tahiri Mohammed Lachkar Bouchaib Manoun Michal Duek Karla Fejfarova 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(12):i120-i124
The crystal structures of three isotypic orthorhombic dihydrogendiphosphates, namely dipotassium copper(II)/nickel(II)/zinc(II) bis(dihydrogendiphosphate) dihydrate, K2M(H2P2O7)2·2H2O (M = Cu, Ni and Zn), have been refined from single‐crystal data. The M2+ and K+ cations are located at sites of m symmetry, and the P atoms occupy general positions. These compounds also exist in triclinic forms with very similar structural features. The structures of both forms are compared, as well as the geometry of the MO6 octahedron, which is considerably elongated towards the water molecules for M = Ni and Cu. Such elongation has not been observed among the other representatives of the family. A Raman study of the whole series K2M(H2P2O7)2·2H2O (M = Mn, Co, Ni, Cu, Zn and Mg) is reported. 相似文献
145.
Mohammed Kara Amine Assouguem Omkulthom Mohamed Al kamaly Safa Benmessaoud Hamada Imtara Hamza Mechchate Christophe Hano Abdou Rachid Zerhouni Jamila Bahhou 《Molecules (Basel, Switzerland)》2021,26(18)
Apple vinegar is a natural product widely used in food and traditional medicine as it contains many bioactive compounds. The apple variety and production methods are two factors that play a major role in determining the quality of vinegar. Therefore, this study aims to determine the quality of apple vinegar samples from different varieties (Red Delicious, Gala, Golden Delicious, and Starking Delicious) prepared by three methods using small apple pieces, apple juice, and crushed apple, through determining the physicochemical properties and antibacterial activity of these samples. The antibacterial activity was studied against five pathogenic bacteria: Staphylococcus aureus, Klebsiella pneumonia, Escherichia coli (ATB: 57), Escherichia coli (ATB: 97), and Pseudomonas aeruginosa, using two methods, disk diffusion and microdilution, for determining the minimum inhibitory concentrations and the minimum bactericidal concentrations. The results of this study showed that the lowest pH value was 3.6 for Stark Delicious, obtained by liquid fermentation, and the highest acetic acid values were 4.7 and 4% for the vinegar of Red Delicious and Golden Delicious, prepared by solid fermentation, respectively. The results of the antibacterial activity showed considerable activity of apple vinegar on the tested strains. Generally, the Staphylococcus aureus strain appears less sensitive and Pseudomonas aeruginosa seems to be very sensitive against all samples, while the other strains have distinct sensitivities depending on the variety studied and the method used. A higher antibacterial activity was found in vinegar obtained by the apple pieces method and the Red Delicious variety, with a low MIC and MBC recorded, at 1.95 and 3.90 µL/mL, respectively. This study has shown that the choice of both apple variety and production method is therefore an essential step in determining and aiming for the desired quality of apple vinegar. 相似文献
146.
Moncef Ati Cristian Enachescu Rachid Bouamrane 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(7):133
In this paper we study the critical behavior of a simple one-dimensional rotor spin in the form of a linear chain with long-range interactions, using the mean field Langevin dynamics approach and in the presence of fluctuations added by a heat bath. We have computed the specific heat, the magnetic susceptibility, the Binder fourth-order cumulant, and the magnetization, and then we have calculated the critical exponents using finite-size scaling. In addition, we provide a relation between the thermal bath temperature and the temperature of the system. Our results confirm the existence of a second-order critical temperature in the one-dimensional chain of spins with long-range interaction. 相似文献
147.
148.
149.
Abdelali El-Bakari Abdellatif Khamlichi Eric Jacquelin Rachid Dkiouak 《Journal of sound and vibration》2014
This paper focuses on the inverse problem regarding force localization in the case of impacts not concentrated at a point but which occur on elastic beams. Following the identification approach proposed to solve this problem and which is based on the reciprocity theorem, the impact location characteristics were determined by using particle swarm optimization algorithm. To eliminate numerical trouble due to the trivial solutions appearing in this formulation, the fitness function was customized by introducing a set of weighting coefficients. Four different formulations of the fitness function were considered and their performances with regards to the number of sensors used and their positions were analyzed. They enabled a selection of the best combination of weighting coefficients to be used in the context of an impact force localization process based on the particle swarm optimization technique. Three sensors were found to be required and comparison with a genetic algorithm has revealed the effectiveness of the proposed method in terms of accuracy and computational time. 相似文献
150.
Mahfoud Ziyad Rachid Ahmamouch Mohamed Rouimi Slimane Gharbage Jacques C. Vdrine 《Solid State Ionics》1998,110(3-4):311-318
Phosphates of general formula M0.5Hf2(PO4)3 with M=Cd2+, Ca2+, Sr2+ and Cu2+ were prepared by coprecipitation and characterized by several physical techniques. The compounds containing Cd2+, Ca2+, Sr2+ belong to the Nasicon-type structure, whereas Cu0.5Hf2(PO4)3 exhibited substantially different DRX patterns. Combined temperature programmed reduction (TPR) and temperature-programmed oxidation (TPO) showed that the copper in Cu0.5Hf2(PO4)3 was distributed between two energetically different sites in proportions respectively equal to 40 and 60%. Electron Paramagnetic Resonance (EPR) investigations confirmed the TPR/TPO results and revealed that the two sites hosting the Cu2+ ions are of orthorhombic symmetry. Moreover, the Cu2+ ions might be reduced by hydrogen to Cu+. These results were also supported by the UV–visible studies that showed the disappearance, under reducing conditions, of the band corresponding to crystal field transitions of Cu2+ ions and the emergence of a new peak attributed to the transitions between (3d)10 and (3d)9(4s)1 Cu+ levels. At the same time, IR spectroscopy confirmed that protons entered the open lattice framework of the material and gave rise to a new protonated phase containing monovalent copper Cu0.5IH0.5Hf2(PO4)3. This redox process was proven to be reversible without any subsequent change in the network of the phosphate. 相似文献