排序方式: 共有179条查询结果,搜索用时 15 毫秒
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Ghasem Karim‐Nezhad Mohammad Hasanzadeh Lotfali Saghatforoush Sohrab Ershad Nasrin Shadjou 《中国化学会会志》2009,56(3):554-560
Electrocatalytic oxidation of acetaldehyde was investigated on a copper electrode in alkaline solution. The process of oxidation involved and its kinetics were established by using cyclic voltammetry and chronoamperometry techniques as well as steady state polarization measurements. It has been found that in the course of an anodic potential sweep the electro‐oxidation of acetaldehyde follows the formation of Cu(III) and is catalysed by this species through a mediated electron transfer mechanism. A mechanism based on the electrochemical generation of Cu(III) active sites and their subsequent consumption by the acetaldehyde in question was also investigated. 相似文献
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Reza Zanjirani Farahani Zvi Drezner Nasrin Asgari 《Annals of Operations Research》2009,167(1):353-368
In this paper a single facility location problem with multiple relocation opportunities is investigated. The weight associated
with each demand point is a known function of time. We consider either rectilinear, or squared Euclidean, or Euclidean distances.
Relocations can take place at pre-determined times. The objective function is to minimize the total location and relocation
costs. An algorithm which finds the optimal locations, relocation times and the total cost, for all three types of distance
measurements and various weight functions, is developed. Locations are found using constant weights, and relocations times
are the solution to a Dynamic Programming or Binary Integer Programming (BIP) model. The time horizon can be finite or infinite. 相似文献
35.
Hojat-Allah Arab Mohammad Ali Faramarzi Nasrin Samadi Hamid Irannejad Alireza Foroumadi Saeed Emami 《Molecular diversity》2018,22(4):815-825
A series of 7-piperazinylquinolones containing a (benzo[d]imidazol-2-yl)methyl moiety were designed and synthesized as new antibacterial agents. The antibacterial activity of title compounds was evaluated against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia) microorganisms. Among the tested compounds, the N1-cyclopropyl derivative 4a showed the highest activity against S. aureus, S. epidermidis, B. subtilis and E. coli (\(\text {MIC} = 0.097\) \(\upmu \)g/mL), being 2–4 times more potent than reference drug norfloxacin. A structure-activity relationship study demonstrated that the effect of the nitro group on the benzimidazole ring depends on the pattern of substitutions on the piperazinylquinolone. 相似文献
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Samadi N Manayi A Vazirian M Samadi M Zeinalzadeh Z Saghari Z Abadian N Mozaffarian VO Khanavi M 《Natural product research》2012,26(20):1931-1934
The essential oil obtained from the flowering parts of Anthemis altissima L. var. altissima was analysed by gas chromatography and gas chromatography mass spectroscopy. In this study, 34 compounds representing 98.76% of the essential oil were identified. The main components were α-terpineol (26.42%), β-pinene (9.23%), cis-chrysanthenyl acetate (6.30%), globulol (5.36%), n-tricosane (4.41%), terpinen-4-ol (4.08%) and 1,8 cineole (3.84%). Antibacterial activities of the essential oil and its two major components (α-terpineol and β-pinene) were determined using microdilution method against both Gram-positive (Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria. The essential oil showed a broad-spectrum antibacterial activity (MICs ranged from 3.13 to 6.25?μL?mL(-1)). It was found that α-terpineol with minimum inhibitory concentration (MIC) values of the range 0.87-1.56?μL?mL(-1) was a more potent antibacterial agent than β-pinene with MIC values of the range 1.56-6.25?μL?mL(-1). All of them, the essential oil, β-pinene and α-terpineol, were more effective against Gram-positive bacteria than Gram-negative ones. 相似文献
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Khodayar Gholivand Nasrin Oroujzadeh Maryam Rajabi 《Journal of the Iranian Chemical Society》2012,9(6):865-876
Ten new N-nicotinyl and N-isonicotinyl phosphoramidates with formula XP(O)R2, X?=?Nicotinamide(nia), R?=?NHCH2Ph (1), N(CH3)CH2Ph (2), NHCH(CH3)Ph (3), NH-CH2C4H3O (4), NHCH2(C5H4N) (5), 3-NH-C5H4N (6), and YP(O)R2, Y?=?isonicotinamide(iso), R?=?NHCH2Ph (7), N(CH3)CH2Ph (8), NHCH(CH3)Ph (9), NH-CH2C4H3O (10) plus one new Er(III) complex with formula Er(L)2(NO3)3 (11), L?=?(iso)PO(NHCH2C4H3O)2 (10), were synthesized and characterized by elemental analysis and 1H, 13C, 31P NMR, IR, UV?Cvis spectroscopy. Crystal structures of compounds 10 and 11 were also determined by X-ray crystallography. Interestingly, the 1H NMR spectra of compounds 1, 2, 6, 7, 9 indicated long-range n J P,H (n?=?5,6,7) coupling constants, in the range of 1.4?C1.9?Hz, for the splitting of pyridine ring protons with phosphorus atom. IR results showed that the ??(C=O) values of compounds 7?C10 are greater than those of compounds 1?C5 which means that isonicotinyl moiety is more electron withdrawing than nicotinyl group. X-ray outcomes revealed that in complex 11 three phosphoric triamide ligands have been connected to each Er(III); one from Npyridine and two from P=O donor sites. One of the P=O donor ligands is mono dentate while the other one acts as a bidentate ligand and coordinates to another Er atom via its Npyridine site. By forming complex 11 the P=O and C?CNamide bond lengths of ligand is increased in both, mono and bi dentate, ligands while the C=O bond length is decreased to lower values. These variations are in good agreement with IR results. All H-bonds and electrostatic interactions lead to form a three-dimensional polymeric cluster in the crystal lattice of 10 and 11. 相似文献
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MCM‐41‐SO3H, an ordered mesoporous silica material in which MCM‐41 with covalently anchored sulfonic acid groups was used as an acidic catalyst for the rapid and ‘green’ synthesis of pyrano[3,2‐c]pyridine derivatives under solvent‐free conditions. Reusability of the catalyst, high yields, short reaction times, simplicity and easy workup are advantages of this novel synthetic procedure compared to the conventional methods reported in the literature. 相似文献
39.
Ricerche di Matematica - Let G be a finite group and $$N \unlhd G$$ . The normal subgroup based power graph of G, $$\Gamma _N(G)$$ , is an undirected graph with vertex set $$(G{\setminus }N) \cup... 相似文献
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Nasrin ZohrehAbdolali Alizadeh 《Tetrahedron》2011,67(25):4595-4600
A facile one-pot synthesis of N-phenyl-3,5-difunctionalized pyrazoles is described. The dialkyl 2-[(Z)-phenylhydrazono]succinate intermediate, which is prepared in situ from the mixture of phenylhydrazine and dialkyl acetylenedicarboxylate reacts with aroyl chloride or fumaryl chloride to afford the title compounds. Different types of compounds containing COCl functional group were used to investigate the scope and limitation of the reaction. Two -CO2R and -O2C groups at 3- and 5-position are potentially capable to convert to other functional groups. The reaction conditions are relatively mild and the yields are good. 相似文献