排序方式: 共有33条查询结果,搜索用时 31 毫秒
1.
Russian Journal of Organic Chemistry - A green protocol has been developed for the preparation of 2,2′-(arylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones) following the... 相似文献
2.
Nesrine Mechi Ismahen Ben Khemis Houcine Dhaou Slim Zghal Abdelmottaleb Ben Lamine 《Chinese Journal of Physics (Taipei)》2018,56(2):449-467
The Mg50Ni45Cr5 alloy for hydrogen storage is prepared by mechanical alloying. First, using the X-ray diffraction (XRD) and the scanning electron microscopy (SEM) we examine the morphology and the structure of the substrate. The obtained results highlight the effectiveness of this alloy in loading hydrogen as it is a nanocrystalline and a ductile one. Second, we attempt to justify these expectations using the statistical physic, precisely the model monolayer with two levels of energy, in modeling a hydrogen absorption and desorption isotherms on Mg50Ni45Cr5 alloy at four temperatures T?=?275?K, T?=?300?K, T?=?325?K and T?=?350?K. The model has six physicochemical parameters deduced from the fitting of the isotherms, they are divided by two categories of steric and energetic parameters. Thanks to these parameters we compare the absorption and desorption processes, in order to highlight the hysteresis phenomenon encountered during the hydrogen sorption. 相似文献
3.
Bouhali Nesrine Azzam-Laouir Dalila Monteiro Marques Manuel D. P. 《Journal of Optimization Theory and Applications》2022,194(1):59-91
Journal of Optimization Theory and Applications - We consider a control problem in a finite-dimensional setting, which consists in finding a minimizer for a standard functional defined by way of... 相似文献
4.
Nesrine Fterich 《Applications of Mathematics》2010,55(1):1-46
The article deals with a nonlinear generalized Ginzburg-Landau (Allen-Cahn) system of PDEs accounting for nonisothermal phase
transition phenomena which was recently derived by A. Miranville and G. Schimperna: Nonisothermal phase separation based on
a microforce balance, Discrete Contin. Dyn. Syst., Ser. B, 5 (2005), 753–768. The existence of solutions to a related Neumann-Robin problem is established in an N ⩽ 3- dimensional space
setting. A fixed point procedure guarantees the existence of solutions locally in time. Next, Sobolev embeddings, interpolation
inequalities, Moser iterations estimates and results on renormalized solutions for a parabolic equation with L
1 data are used to handle a suitable a priori estimate which allows to extend our local solutions to the whole time interval.
The uniqueness result is justified by proper contracting estimates. 相似文献
5.
Ammar S Mahjoub MA Charfi N Skandarani I Chekir-Ghedira L Mighri Z 《Chemical & pharmaceutical bulletin》2007,55(3):385-388
A new skeleton of an O-heteroside natural substance named zinolol, the first representative of a new class of aminated hydroxyhydroquinone, has been isolated from the whole plant Anagallis monelli. Its structure has been established by one and two dimensional NMR spectroscopic procedures. Antioxidant, mutagenic, antimutagenic activities were realised and positive results were recorded. 相似文献
6.
Aissaoui N Bergaoui L Landoulsi J Lambert JF Boujday S 《Langmuir : the ACS journal of surfaces and colloids》2012,28(1):656-665
In this work the mechanism of (3-aminopropyl)triethoxysilane (APTES) interaction with silicon surfaces is investigated at the molecular level. We studied the influence of experimental parameters such as time, temperature, and concentration on the quality of the APTES layer in terms of chemical properties, morphology, and stability in aqueous medium. This was achieved using a highly sensitive IR mode recently developed, grazing angle attenuated total reflection (GA-ATR). This technique provides structural information on the formed APTES layer. The topography of this layer was investigated by atomic force microscopy in aqueous medium. The hydrophilicity was also studied using contact angle measurement. Combining these techniques enables discussion of the mechanism of silane grafting. Considerable differences were observed depending on the reaction temperature, room temperature or 90 °C. The data suggest the presence of two adsorption sites with different affinities on the oxidized silicon layer. This also allows the optimal parameters to be established to obtain an ordered and stable silane layer. The adsorption of proteins on the APTES layer was achieved and monitored using in situ quartz crystal microbalance with dissipation monitoring and ex situ GA-ATR analyses. 相似文献
7.
In situ ATR-FTIR spectroscopy coupled with in situ image acquisition measurements were used to determine the solubility curve and to investigate the metastable zone width (MSZW) of ammonium oxalate monohydrate (AO) aqueous solutions under polythermal conditions. The experimental data allowed estimating the MSZW and induction time of the system and the results were compared with published literature values for the same system [1]. “Pseudo” induction time estimation techniques based on polythermal methods showed that AO aqueous solutions exhibit two nucleation regimes depending on the cooling rates.Even though they are based on rough and questionable assumptions, induction time and MSZW estimation methods are often considered as essential for the development of industrial crystallization processes. However, both the relevancy and the physical meaning of the results provided by these methods are uncertain. In the actual industrial context where many advanced measurement techniques and modeling tools became available, the present paper intends to call into question the outcome of the notions of MSZW and induction time. 相似文献
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9.
Melek Hajji Hasan Mtiraoui Nesrine Amiri Moncef Msaddek Taha Guerfel 《International journal of quantum chemistry》2019,119(21):e26000
The present work arose out of a desire to fundamentally understand the molecular geometry, weak interactions, electron density delocalization, and chemical reactivity features of 1,5-benzodiazepines-containing family. Herein, a complete X-ray crystallographic study, supported by trustworthy sets of computational approaches, has been reported for two organic crystals. Quantifying intramolecular and intermolecular interactions by Hirshfeld-Becke surfaces analysis conjointly with noncovalent interaction-reduced density gradient topological study revealed that supramolecular assemblies are stabilized by N-H … O (inter) and O-H … N (intra) hydrogen bonds, Cg … Cg (π … π) and C-H(O) … π intercontacts, as well as Van der Waals interactions and steric effects. The long-range-corrected functional wB97XD, which uses Grimme's D2 dispersion model, seems to be just right for our systems. The quantum theory of atoms in molecules analysis confirms that both significant O1-H1…N1 and N2-H2A…O2 H-bonds are weak and electrostatic in nature. Furthermore, global reactivity indices computed via the conceptual density functional theory framework allows these molecules to be classified as moderate electrophiles and marginal nucleophiles. The active sites favorable for nucleophilic/electrophilic attacks were also predicted based on local Parr functions. Finally, a comparative evaluation on the aromaticity character and π-π stacking ability has been done for different (pseudo) rings. 相似文献
10.
Nesrine Zaouadi Benamar Cheknane Abdelkader Hadj-Sadok Jean Paul Canselier 《Journal of Dispersion Science and Technology》2013,34(1):94-102
The main objective of this study is to develop a new formula for a diet mayonnaise-like sauce without cholesterol. Emulsifying power is provided by the use of soy lecithin and the total fat content was limited to 16%. Droplet size measurement of employed mayonnaise samples at different times show that the largest diameter of fat does not exceed 18.5 µm with a yield stress of 56.1 Pa. Results of stability to centrifugation reveal that the absence of the supernatant oily layer ensures the stability of the emulsion. Using the experimental design method, the number of trials can be limited to a number of 16 experiments, and best formulation of the mayonnaise (without cholesterol) was obtained. 相似文献