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排序方式: 共有311条查询结果,搜索用时 15 毫秒
61.
Katayoun Marjani Mohsen Mousavi Fatemeh Namazian 《Journal of chemical crystallography》2011,41(10):1451-1455
Abstract
The crystal structure of amino containing Schiff base, N-(2-pyridylmethylene)benzene-1,4-diamine, was determined via X-ray diffraction analysis. The title compound crystallizes in orthorhombic system, space group Pc2 1 n, with unit cell dimensions a = 5.8945(6), b = 11.9233 (10), c = 14.5356 (16) ?, V = 1021.59 (18) ?3, Z = 4. The molecules are linked by intermolecular N–H···N hydrogen bonds to form supramolecular sheets along with the bc crystallographic plane. The crystal structure is further stabilized by C–H···π stacking interactions. 相似文献62.
Heshmatollah Alinezhad Mahmood Tajbakhsh Mahboobeh Zare Mahboobeh Mousavi 《Heteroatom Chemistry》2016,27(5):290-294
Phenylphosphinic acid is found to catalyze the three‐component condensation of an aldehyde, enaminone, and urea or thiourea to afford the corresponding 6‐unsubstituted dihydropyrimidinones in high to excellent yields. This methodology is simple and fast synthetic route for the preparation of interesting class of heterocycles. 相似文献
63.
In this paper, we investigate the finite groups all of whose non-normal nilpotent subgroups are cyclic. We show that such groups are solvable with cyclic centers. If G is a non-supersolvable group, then G has only one non-cyclic Sylow subgroup which is either isomorphic to Q8 or is of type (q, q). 相似文献
64.
M. Masteri-Farahani A. Ezabadi R. Mazarei P. Ataeinia S. Shahsavarifar F. Mousavi 《应用有机金属化学》2020,34(8):e5727
Intercalation of cetyltrimethylammonium (CTA+) cations within the nanolayers of montmorillonite (MMT) clay followed by reaction with Keggin-type phosphomolybdic acid (PMo) resulted in the synthesis of (CTA)3PMo-MMT nanocomposite catalyst. The prepared nanocomposite catalyst was characterized using different physicochemical methods such as Fourier-transform infrared and inductively coupled plasma–optical emission spectroscopies, X-ray diffraction, and nitrogen adsorption–desorption (Brunauer–Emmett–Teller method) analyses. Characterization techniques demonstrated the intercalation of (CTA)3PMo species into the nanolayers of MMT. The resulting (CTA)3PMo-MMT nanocomposite catalyst efficiently catalyzed the synthesis of 2,4,5-trisubstituted imidazoles under solvent-free conditions. The efficiency is due to the fact that the presence of CTA+ species makes the nanocomposite catalyst hydrophobic and facilitates the accessibility of hydrophobic reactants to active sites in the course of the reaction. High activity and selectivity were achieved in the presence of the prepared nanocomposite catalyst. The nanocomposite catalyst was readily isolated from the reaction mixture using simple filtration, washed with ethanol, and recycled five times without a major loss of activity. 相似文献
65.
Samaneh Soloukipour Ehsan Saljoughi Seyed Mahmoud Mousavi Mahdi Pourafshari Chenar 《先进技术聚合物》2017,28(1):113-123
In the present research, novel polyether block amide (PEBA)/polyvinyldene fluoride (PVDF) blend pervaporation (PV) membranes were prepared for the removal of isopropyl alcohol (IPA) from the aqueous solution. The membranes obtained at PEBA/PVDF ratios of 100/0, 95/5, and 90/10 were characterized using scanning electron microscopy, thermogravimetric analysis, water contact angle measurement, and tensile test. Moreover, the PV performance of the membranes was assessed via separation of IPA from the aqueous solution. The blended membranes exhibited higher hydrophobicity and separation factor as well as lower permeability in comparison with the pure PEBA membrane. The blended membrane that was prepared at PEBA/PVDF ratio of 95/5 was found as the optimum membrane providing PV separation index of 3171 that appeared to be the maximum value. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
66.
Hamze Mousavi Jamshid Moradi Kurdestany Mehran Bagheri 《Applied Physics A: Materials Science & Processing》2012,108(2):283-289
The effect of gas molecule adsorption is investigated on the density of states of (9,0) zigzag boron nitride nanotube within a random tight-binding Hamiltonian model. The Green function approach and coherent potential approximation have been implemented. The results show that the adsorption of carbon dioxide gas molecules by boron atoms only leads to a donor type semiconductor while the adsorption by nitrogen atoms only leads to an acceptor. Since the gas molecules are adsorbed by both boron and nitrogen atoms, a reduction of the band gap is found. In all cases, increasing the gas concentration causes an increase in the height of the peaks in the band gap. This is due to an increasing charge carrier concentration induced by adsorbed gas molecules. 相似文献
67.
The dynamic behaviors of several moving cracks in a functionally graded piezoelectric (FGP) strip subjected to anti-plane mechanical loading and in-plane electrical loading are investigated. For the first time, the distributed dislocation technique is used to construct the integral equations for FGP materials, in which the unknown variables are the dislocation densities. With the dislocation densities, the field intensity factors are determined. Moreover, the effects of the speed of the crack propagation on the field intensity factors are studied. Several examples are solved, and the numerical results for the stress intensity factor and the electric displacement intensity factor are presented graphically finally. 相似文献
68.
Mojtaba Shamsipur Morteza Hosseini Mohammad Mehdi Eskandari Mir Fazlollah Mousavi 《Analytica chimica acta》2003,486(1):93-99
New polymeric membrane (PME) and coated graphite (CGE) samarium(III)-selective electrodes were prepared based on isopropyl 2-[(isopropoxycarbothioyl) disulfanyl]ethanethioate as a suitable neutral ionophore. The electrodes exhibit Nernstian slopes for Sm3+ ions over wide concentration ranges (1.0×10−5 to 1.0×10−1 M for PME and 1.0×10−6 to 1.0×10−1 M for CGE). The PME and CGE have limits of detection of 3.1×10−6 and 5.0×10−7 M, respectively, and response times of about 20 s. The potentiometric responses are independent of the pH of the test solution in the pH range 4.0-7.0. The proposed electrodes revealed good selectivities over a wide variety of other cations including alkali, alkaline earth, transition and heavy metal ions. The electrodes were successfully applied to the recovery of Sm3+ ion from tap water samples and also, as an indicator electrode, in potentiometric titration of samarium(III) ions. 相似文献
69.
Behnam Vahdani S.H. Iranmanesh S. Meysam Mousavi M. Abdollahzade 《Applied Mathematical Modelling》2012
Supplier selection and evaluation is a complicated and disputed issue in supply chain network management, by virtue of the variety of intellectual property of the suppliers, the several variables involved in supply demand relationship, the complex interactions and the inadequate information of suppliers. The recent literature confirms that neural networks achieve better performance than conventional methods in this area. Hence, in this paper, an effective artificial intelligence (AI) approach is presented to improve the decision making for a supply chain which is successfully utilized for long-term prediction of the performance data in cosmetics industry. A computationally efficient model known as locally linear neuro-fuzzy (LLNF) is introduced to predict the performance rating of suppliers. The proposed model is trained by a locally linear model tree (LOLIMOT) learning algorithm. To demonstrate the performance of the proposed model, three intelligent techniques, multi-layer perceptron (MLP) neural network, radial basis function (RBF) neural network and least square-support vector machine (LS-SVM) are considered. Their results are compared by using an available dataset in cosmetics industry. The computational results show that the presented model performs better than three foregoing techniques. 相似文献
70.
In [1], we defined c(G), q(G) and p(G). In this paper we will show that if G is a p-group, where p is an odd prime and |G| ≤ p
4, then c(G) = q(G) = p(G). However, the question of whether or not there is a p-group G with strict inequality c(G) = q(G) < p(G) is still open. 相似文献