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排序方式: 共有141条查询结果,搜索用时 15 毫秒
1.
We carry out the classification of abelian Lie symmetry algebras of two-dimensional second-order nondegenerate quasilinear evolution equations. It is shown that such an equation is linearizable if it admits an abelian Lie symmetry algebra that is of dimension greater than or equal to 5 or of dimension greater than or equal to 3 with rank-one. 相似文献
2.
A series of β‐hydroxynitriles were efficiently synthesized from the regioselective ring opening of oxiranes by cyanide anion in the presence of silica‐bound 3‐{2‐[poly(ethylene glycol)]ethyl}‐substituted 1‐methyl‐1H‐imidazol‐3‐ium bromide (SiO2? PEG? ImBr) as a novel recoverable phase‐transfer catalyst in H2O (Scheme 1 and Table 2). The workup procedure was straightforward, and the catalyst could be reused over four times with almost no loss of catalytic activity and selectivity. 相似文献
3.
In the present study, the synthesis of mordenite zeolite/MIL‐101(Cr) metal–organic framework (MOF) composite [MOR/MIL‐101(Cr)] using the ship in a bottle method was suggested. The properties of prepared composite and individual MOF and MOR zeolite were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption measurement, and thermogravimetric analysis (TGA). The XRD results indicated diffraction peaks for each compound (MOR and MOF) in composite. The SEM and TEM images showed the formation of plates MOR (with size of 2.5 × 3 μm) along with spherical particles MIL‐101. The Brunauer–Emmett–Teller results showed that the surface area of the composite was smaller than individual MOF and MOR zeolite. Based on TGA plots, the hybrid zeolite/MOF composite was more thermally stable compared with the isolated MIL‐101(Cr). The composite was functionalized by post‐synthetic modification to obtain acid–base bifunctionality (H‐MOR/MIL‐101‐ED) for the synthesis of chromene derivatives. The acidity from framework Al‐O(H)‐Si sites in MOR and basicity from amine groups in MIL‐101 were obtained by post‐synthetic modification. 相似文献
4.
Transport in Porous Media - Given the analogy between the filtered equations of large eddy simulation and volume-averaged Navier–Stokes equations in porous media, a subgrid-scale model is... 相似文献
5.
Antibacterial and antibiofilm activity of nanochelating based silver nanoparticles against several nosocomial pathogens 下载免费PDF全文
Seyedeh Mahsan Hoseini‐Alfatemi Abdollah Karimi Shahnaz Armin Saideh Fakharzadeh Fatemeh Fallah Somayeh Kalanaky 《应用有机金属化学》2018,32(5)
The emergence of multi‐drug resistant (MDR) bacteria and dynamic pattern of infectious diseases demand to develop alternative and more effective therapeutic strategies. Silver nanoparticles (AgNPs) are among the most widely commercialized engineered nanomaterials, because of their unique properties and increasing use for various applications in nanomedicine. This study for the first time aimed to evaluate the antibacterial and antibiofilm activities of newly synthesized nanochelating based AgNPs against several Gram‐positive and ‐negative nosocomial pathogens. Nanochelating technology was used to design and synthesize the AgNPs. The cytotoxicity was tested in human cell line using the MTT assay. AgNPs minimal inhibitory concentration (MIC) was determined by standard broth microdilution. Antibiofilm activity was assayed by a microtiter‐plate screening method. The two synthesized AgNPs including AgNPs (A) with the size of about 20‐25 nm, and AgNPs (B) with 30‐35 nm were tested against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, and Pseudomonas aeruginosa. AgNPs exhibited higher antibacterial activity against Gram‐positive strains. AgNPs were found to significantly inhibit the biofilm formation of tested strains in concentration 0.01 to 10 mg/mL. AgNPs (A) showed significant effective antibiofilm activity compared to AgNPs (B). In summary, our results showed the promising antibacterial and antibiofilm activity of our new nanochelating based synthesized AgNPs against several nosocomial pathogens. 相似文献
6.
7.
Ali Reza Kiasat Foad Kazemi Mehdi Fallah Mehr Jardi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1841-1844
A simple and efficient method for the conversion of various oxiranes to the corresponding thiiranes using thiourea under solvent free conditions is described. 相似文献
8.
This study was performed to determine the concentrations of cadmium, lead, copper and zinc in the edible muscle of pelagic (Scomberomorus commerson, Chirocentrus dorab, Sphyraena jello, Rachycentron conadum, Thunus tonggol, and Tenualosa ilisha) and demersal (Nemipterus japonicas, Epinephelus coioides, Platycephalus indicus, Psettodes erumei, Pomadasys argenteus, and Acanthopagrus latus) fish species from the Persian Gulf during winter and summer. The samples were analyzed by the derivative potentiometric stripping technique; and the results were expressed as μg/g of wet weight. The obtained range of metals in fish species was 0.024–0.111 μg/g for cadmium, 0.057–0.471 μg/g for lead, 0.799–4.790 μg/g for copper and 3.226–11.390 μg/g for zinc. The study revealed that seasonal variation influenced the concentration of metals in the samples. The highest concentration of cadmium, lead, copper and zinc was found in Platycephalus indicus (0.147 μg/g), Acanthopagrus latus (0.534 μg/g), Psettodes erumei (5.294 μg/g) and Psettodes erumei (13.528 μg/g) in winter, respectively. Moreover, demersal fish species had higher cadmium, lead and zinc concentrations, but lower copper content than pelagic ones. Our study demonstrated that the estimated daily and weekly intakes of lead, copper and zinc, and estimated monthly intake of cadmium via consumption of fish flesh were below the PTDI, PTWI and PTMI values established by FAO/WHO. 相似文献
9.
A. Fallah M. M. Aghdam M. H. Kargarnovin 《Archive of Applied Mechanics (Ingenieur Archiv)》2013,83(2):177-191
Free vibration analysis of moderately thick rectangular FG plates on elastic foundation with various combinations of simply supported and clamped boundary conditions are studied. Winkler model is considered to describe the reaction of elastic foundation on the plate. Governing equations of motion are obtained based on the Mindlin plate theory. A semi-analytical solution is presented for the governing equations using the extended Kantorovich method together with infinite power series solution. Results are compared and validated with available results in the literature. Effects of elastic foundation, boundary conditions, material, and geometrical parameters on natural frequencies of the FG plates are investigated. 相似文献
10.
A New Approach for Titration Calorimetric Data Analysis on the Binding of Magnesium Ion with Myelin Basic Protein 总被引:1,自引:0,他引:1
G. Rezaei Behbehani A. A. Saboury A. Fallah Baghery 《Journal of solution chemistry》2008,37(8):1127-1135
The interaction of the myelin basic protein (MBP) from the bovine central nervous system with divalent magnesium ion was studied
by isothermal titration calorimetry at 27 °C in aqueous solution. A simple rapid method for determination of the dissociation
binding constants for Mg2+-MBP interaction was introduced using the isothermal titration calometric data. The binding isotherm for Mg2+-MBP interaction is easily obtained by carrying out a titration calorimetric experiment using only one set of concentrations
of MBP. There are two identical independent intrinsic association constants equal to 0.021 μmol⋅L−1 in the first- and second-binding sites, respectively. 相似文献