排序方式: 共有115条查询结果,搜索用时 359 毫秒
61.
Zinc oxide‐decorated superparamagnetic silica attached to graphene oxide (Fe3O4/SiO2/PTS‐GO‐ZnO), as a novel nanocomposite, was designed, and its core‐shell structure was appropriately characterized by different spectroscopy or microscopy methods and thermal techniques as well as measuring of its porosity and magnetic properties. The catalytic activity of Fe3O4/SiO2/PTS‐GO‐ZnO, as a reusable heterogeneous catalyst, was investigated for efficient one‐pot multi‐component synthesis of medicinally important functionalized 2‐amino‐6‐(2‐oxo‐2H‐chromen‐3‐yl)‐4‐arylnicotinonitrile derivatives. The significant features of the present procedure are mild reaction conditions, low loading of the catalyst, high to quantitative yields of the desired products, avoiding the use of toxic heavy metals or solvents, simple isolation and purification of the products, and stability as well as reusability of the catalyst after at least six consecutive runs. 相似文献
62.
R. Arasteh M. Omidi A. H. A. Rousta H. Kazerooni 《Journal of Macromolecular Science: Physics》2013,52(12):2464-2480
In order to improve the precision in prediction of mechanical properties of multi-walled carbon nanotubes (MWNTs)/epoxy composites, the effect of waviness of nanotubes is considered by applying a correction factor to a modified Halpin–Tsai equation. Data validation was carried out through the comparison of theoretical data with real mechanical test results obtained by the authors and in the literature. Tensile tests of various weight percents (wt%) of MWNT/epoxy composites were carried out to obtain the mechanical properties of MWNT/epoxy composites. Applicability of the proposed modification of Halpin–Tsai equation was endorsed by the experimental results and was found to be more accurate in comparison with results obtained from the same equation without considering the waviness effect. 相似文献
63.
64.
65.
Reza Heydari Malek Taher Maghsoodlou Sayyed Mostafa Habibi-khorassani Nourallah Hazeri Farahnaz Barahuie Mohsen Rostamizadeh 《Arabian Journal of Chemistry》2010,3(4):229-232
Stable crystalline phosphorus ylides and 1,4-diionic organophosphorus compounds were obtained in good to excellent yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates and β-dicarbonyl or heterocyclic compounds, such as diethyl malonate, acetyl acetone, 1,3-diphenyl propane-1,3-dione, 1,3-dimethylbarbituric acid, meldrum’s acid, 2-benzoxazolinone, benzotirazole, and 2-thiazoline-2-thiol in the presence of sodium dodecyl sulfate as a surfactant in water. Green synthesis, mild conditions, decreasing timescale of reaction, low cost, and easy workup are the main advantages of this method. 相似文献
66.
Novel 1,4-dihydropyridines (1,4-DHPs) are prepared efficiently via Hantzsch reaction using aldehydes, benzylacetoacetate and catalytic amount of iron(III) phosphate under solvent-free conditions in good yields. 相似文献
67.
Javad Shabani Shayeh Ali Ehsani Ali Naeemy Hamid Mohammad Shiri Fataneh Fatemi Amir Yadegari Meisam Omidi 《Ionics》2018,24(2):505-511
In this work, supercapacitive performance of polyaniline/yttrium aluminum garnet (YAG: Y3Al5O12) nanoparticles (PANI/YAGNPs) was studied. YAG nanoparticles were synthesized by pulse electro-deposition method and after that, PANI/YAGNPs electrodeposited on the surface of glassy carbon electrodes through cyclic voltammetry. Morphological studies show that YAG nanoparticles were distributed in the structure of PANI filaments uniformly. XRD and FTIR were used to perform a structural study of materials. Different electrochemical techniques such as cyclic voltammetry (CV), galvano static charge discharge (CD), and impedance spectroscopy (EIS) were used to evaluate the applicability of using PANI/YAGNPs as an active material for supercapacitors. The specific capacitance (SC) of PANI and PANI YAG NPs electrodes calculated using CV technique are 240 and 440 F/g, respectively. Increasing the conductivity and stability of composite electrodes during continuous CD cycles compared to PANI ones are some features of using YAG NPs in the structure of polymer electrodes. Stability of composite electrodes remains about 98% through 1000 continuous cycles whereas the polymeric electrode loses about 91% of its capacitance during this time range. 相似文献
68.
Farahnaz Hamzehee Duane Choquesillo-Lazarte 《Phosphorus, sulfur, and silicon and the related elements》2017,192(3):359-367
Two novel phosphinic amides, (C6H5)2P(O)(NH?cyclo?C7H13) (I) and (C6H5)2P(O)(NH?cyclo?C6H11) (II) were synthesized and characterized by spectroscopic methods and X-ray crystallography. Both compounds crystallize in the orthorhombic chiral space group P212121 and in both structures, the N—H···O hydrogen bonds lead to one-dimensional arrangements along the a axis. The molecular geometries and vibrational frequencies of I and II were investigated with quantum chemical calculations at the B3LYP/6–311G** level of theory. Furthermore, the hydrogen bonds were studied by means of the Bader theory of atoms in molecules (AIM) and natural bond orbital (NBO) analysis. 相似文献
69.
70.
Aleem Gangjee Farahnaz Mavandadi Sherry F. Queener 《Journal of heterocyclic chemistry》2001,38(1):213-220
The effect of conformational restriction of the C9‐N10 bridge on inhibitory potency and selectivity of trimetrexate against dihydrofolate reductase, was studied. Specifically three nonclassical tricyclic 1,3‐diamino‐8‐(3′,4′,5′‐trimethoxybenzyl)‐7,9‐dihydro‐pyrrolo[3,4‐c]pyrido[2,3‐d]pyrimidin‐6(5H,8H)‐one ( 4 ), 1,3‐diamino‐8‐(3′,4′,5′‐trimethoxybenzyl)‐9‐hydro‐pyrrolo[3,4‐c]pyrido[2,3‐d]pyrimidin‐6‐(8H)‐one ( 5 ) and 1,3‐diamino‐(8H)‐(3′,4′,5′‐trimethoxybenzyl)‐7,9‐dihydro‐pyrrolo[3,4‐c]pyrido[2,3‐d]pyrimidine ( 7 ) antifolates were synthesized. The tricyclic analogues 4 and 5 were obtained via the regiospecific cyclo‐condensation of the β‐keto ester 17 with 2,4,6‐triaminopyrimidine. The analogue 7 was obtained via reduction of the lactam 4 with borane in tetrahydrofuran. Compounds 4, 5 and 7 were evaluated as inhibitors of dihydrofolate reductase from Pneumocystis carinii, Toxoplasma gondii and rat liver. All three compounds were more selective than trimetrexate against Pneumocystis carinii dihydrofolate reductase and significantly more selective than trimetrexate against Toxoplasma gondii dihydrofolate reductase compared with rat liver dihydrofolate reductase. 相似文献