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排序方式: 共有85条查询结果,搜索用时 31 毫秒
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Stability analysis of jointed rock slope 总被引:2,自引:0,他引:2
The stability analysis of a jointed rock slope with two sets of unfilled joints, under its own weight, is carried out directly by considering failure surfaces along some particular joints and also going through the intact rock. Simple failure mechanisms using uniform rigid rock-block motions are incorporated in the yield design kinematic approach. They yield an improvement of known results as long as the characteristics strength of the joints are weak enough. 相似文献
3.
Ayoub Abdelkader Mekkaoui Abderrazak Aberkouks Lahcen Fkhar Mustapha Ait Ali Larbi El Firdoussi Soufiane El Houssame 《应用有机金属化学》2020,34(11):e5917
Various ratios of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) were prepared using the wetness impregnation method. The prepared catalysts were characterized by IR, XRD, CV, SEM, EDX, XRF, TEM and BET analysis. The reduction and preparation of the palladium nanoparticles afford a crystallite size of 10.88 nm. The performance of the synthesized catalyst was investigated in the solvent-free dehydroaromatization of α-, β- and γ-himachalene mixture from Cedrus atlantica oil as a model substrate. In order to achieve an efficient and selective catalysis, the catalytic dehydroaromatization of various terpenes such as limonene, limonaketone, carvone, carveol and perillyl alcohol was studied. The Pd@NP catalyst performed a high catalytic activity, selectivity and recyclability in the terpenes dehydroaromatization reaction. 相似文献
4.
Oularbi Larbi Turmine Mireille El Rhazi Mama 《Journal of Solid State Electrochemistry》2017,21(11):3289-3300
Journal of Solid State Electrochemistry - In this paper, a new nanocomposite of polypyrrole (PPy) and carbon nanofibers (CNFs)-modified carbon paste electrode (CPE) has been reported for the... 相似文献
5.
The ability to graft apatite surface by specific ligand fields creates powerful new technology applications. Thus, grafted organophosphonate can provide an effective route to modify the surface properties of apatite materials. The ability to decorate the apatite surface with the desired functionality requires covalent attachment to solid interface; most commonly achieved using organophosphonate self‐assembly. The current study shows that various phosphonates can react with calcium ions and control the formation of the porous apatite with high surface areas as well as the porosity. The structural and surface properties are given some importance in this review. 相似文献
6.
Mohammed Larbi Labbi 《Mathematische Nachrichten》2015,288(4):402-411
The Weitzenböck curvature operators are the curvature terms of order zero that appear in the well‐known classical Weitzenböck formula. In this paper, we use the formalism of double forms to prove a simple formula for these operators and to study their geometric properties. 相似文献
7.
Naima Bouyahia Mohamed Larbi Hamlaoui Mouna Hnaien Florence Lagarde Nicole Jaffrezic-Renault 《Bioelectrochemistry (Amsterdam, Netherlands)》2011,80(2):155-161
In this work, a new biosensor was prepared through immobilization of bovine liver catalase in a photoreticulated poly (vinyl alcohol) membrane at the surface of a conductometric transducer. This biosensor was used to study the kinetics of catalase–H202 reaction and its inhibition by cyanide. Immobilized catalase exhibited a Michaelis–Menten behaviour at low H202 concentrations (< 100 mM) with apparent constant KMapp = 84 ± 3 mM and maximal initial velocity VMapp = 13.4 μS min? 1. Inhibition by cyanide was found to be non-competitive and inhibition binding constant Ki was 13.9 ± 0.3 μM. The decrease of the biosensor response by increasing cyanide concentration was linear up to 50 μM, with a cyanide detection limit of 6 μM. In parallel, electrochemical characteristics of the catalase/PVA biomembrane and its interaction with cyanide were studied by cyclic voltammetry and impedance spectroscopy. Addition of the biomembrane onto the gold electrodes induced a significant increase of the interfacial polarization resistance RP. On the contrary, cyanide binding resulted in a decrease of Rp proportional to KCN concentration in the 4 to 50 μM range. Inhibition coefficient I50 calculated by this powerful label-free and substrate-free technique (24.3 μM) was in good agreement with that determined from the substrate-dependent conductometric biosensor (24.9 μM). 相似文献
8.
In reversed phase liquid chromatography (RP-LC), the validity of a multiparametric (MP) non-linear least-squares regression iterative method has been evaluated for 14 different aqueous mobile phases modified with one, two or three organic solvents [acetonitrile (ACN), methanol (MeOH), or tetrahydrofuran (THF)] for calculating the retention time of unretained compound t M and the regression parameter (slope b), based on the use of alkan-2-ones and alkyl aryl ketones homologous series. The determination of t M and b has been studied for eight binary (ACN?CH2O or MeOH?CH2O), 3 ternary (ACN?CMeOH?CH2O) and 3 quaternary (ACN?CMeOH?CTHF?CH2O) mobile phase systems on an Omnispher C18 column. The multiparametric calculated t M and b values were compared with those obtained by Guardino??s, and Grobler??s methods. The MP retention indices (RI) of ten monosubstituted benzenes with different functionality (hydroxyl, carbonyl, nitro, etc.) based on the alkan-2-ones retention index standards have been determined and compared for the different mobile phase compositions studied. The influence of organic modifier type, the nature of mobile phase system and water content on the variation of retention parameter studied in this work were discussed. 相似文献
9.
Grégoire Fourrié Laurent Keirsbulck Larbi Labraga Patrick Gilliéron 《Experiments in fluids》2011,50(2):385-395
A passive flow control on a generic car model was experimentally studied. This control consists of a deflector placed on the
upper edge of the model rear window. The study was carried out in a wind tunnel at Reynolds numbers based on the model height
of 3.1 × 105 and 7.7 × 105. The flow was investigated via standard and stereoscopic particle image velocimetry, Kiel pressure probes and surface flow
visualization. The aerodynamic drag was measured using an external balance and calculated using a wake survey method. Drag
reductions up to 9% were obtained depending on the deflector angle. The deflector increases the separated region on the rear
window. The results show that when this separated region is wide enough, it disrupts the development of the counter-rotating
longitudinal vortices appearing on the lateral edges of the rear window. The current study suggests that flow control on such
geometries should consider all the flow structures that contribute to the model wake flow. 相似文献
10.
Asma Kaoukabi Larbi Belachemi Mohammed Lahcini Marie‐Claude Viaud Massuard Ccile Croix 《Journal of heterocyclic chemistry》2019,56(4):1260-1274
In an attempt to improve anticancer activity, a series of retinoids–chromene hybrids was described. The novel heterocyclic chromene–retinoids hybrid including oxygen as a heteroatom in a six‐membered cyclic ring (2H‐chromene or 2H‐1‐benzopyran) was designed and synthesized by introducing different groups such as an aromatic or styrylphenyl ring in 6‐position of 2H‐chromene. These novel compounds were synthesized by using the efficient cascades one‐pot process involving Wittig–Horner–Emmons reaction and Suzuki–Miyaura cross‐coupling pallado‐catalyzed reactions with 60% to 90% overall yields. These new compounds were tested against glioblastoma multiforme brain cancer, medulloblastoma, neuroblastoma cell lines, and breast cancer MCF‐7 cell lines. Two of them exhibited an appreciable anti‐tumor activity in the low micromolar range, which opens new perspectives for therapeutic application on humans. 相似文献