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排序方式: 共有141条查询结果,搜索用时 31 毫秒
61.
Khalil Tabatabaeian Abdollah Fallah Shojaei Farhad Shirini Seyyedeh Zoha Hejazi Mehdi Rassa 《中国化学快报》2014,25(2):308-312
An efficient, convenient and environmentally benign one-pot multicomponent reaction for the preparation of pyrimido[4,5-b]quinoline derivatives as biologically, pharmacologically and antibacte- rially active products has been developed using RuC13.xH20 as a reusable homogenous catalyst. Use of water as a green solvent, purification of products by non-chromatographic methods, reusability of transition metal homogenous catalyst, saving energy by employing multicomponent reactions, short reaction times and high yields, are some of the advantages of this process. 相似文献
62.
Nitrogen-doped TiO2 (N-TiO2) were prepared by the impregnation method using urea as a nitrogen source and TiO2-P25 as precursor. N-TiO2 was characterized by x-ray diffraction (XRD), UV–vis diffusion reflectance spectra (UV–vis DRS), Fourier transform infrared spectroscopy (FTIR), and x-ray photoelectron spectroscopy (XPS) techniques. XPS analysis indicates the incorporation of nitrogen in TiO2 lattice as O–Ti–N linkage. DRS spectra reveal the extended absorption to the visible range. Photocatalytic performance of the N-TiO2 was studied by testing the degradation rate of aqueous styrene under visible light. Also, the degradation kinetics of aqueous styrene and possibility of cyclic usage of N-TiO2 were investigated. 相似文献
63.
Valtchev V Balanzat E Mavrodinova V Diaz I El Fallah J Goupil JM 《Journal of the American Chemical Society》2011,133(46):18950-18956
The present study demonstrated the possibility to form a secondary system of parallel macropores in zeolite crystals. The secondary pore formation was predetermined by the creation of defect zones in ZSM-5 crystals. A high energy (238)U ion beam was employed to form latent tracks in zeolite crystals, which were further subjected to attack with diluted HF solution and thus developed to uniformally sized macropores. The selective extraction of material from latent tracks was due to the higher etching velocity of highly agitated zones created by heavy ion bombardment. The combination of complementary methods unambiguously demonstrated the formation of hierarchical zeolite material comprising parallel macropores that extended through the entire crystal. The catalytic tests revealed improved activity at retained selectivity in the reaction of m-xylene conversion. The possibility to control the number of macropores per unit of crystal surface and thus the catalytic performance of the material was demonstrated. This model material is expected to bring better understanding to the effect of a secondary pore system in the catalytic performance of hierarchical zeolites obtained by the top-down or bottom-up approach. 相似文献
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Transport in Porous Media - We present numerical simulations of post-Darcy flow in thin porous medium: one consisting of staggered arrangements of circular cylinders and one random distribution of... 相似文献
67.
The synergistic effect between ammonium bromide and antimony(III) oxide as a nondurable finish on the flammability of 100% woven plain cotton fabric (with a density of 144 g/m2, the number of yarns 21 per 10 mm), has been investigated in this study. The laundered totally-dried, weighed specimens were impregnated with suitable concentration individual aqueous ammonium bromide and/or antimony(III) oxide suspension solutions and some sets were impregnated with appropriate admixed solutions of the both chemicals. A vertical flame spread test was then carried-out to characterize the flammability of the samples. An acceptable synergistic effect was then experienced by using an admixed bath containing 0.1 molar ammonium bromide and 0.05 unit formal antimony trioxide solutions for impartation of flame-retardancy to a cotton fabric. The optimum mass of the mixture required to impart flame-retardancy was about 3.64 g of anhydrous additives per 100 g of fabric. The results obtained are in favor of Wall Effect Theory. Moreover synergistic effect indicating dehydration of the treated substrate by using this combination via thermogravimetry could be deduced. 相似文献
68.
Hossein Hosseinzadeh Soleyman Hosseinzadeh Shahryar Pashaei Naser Ghorbani Rohollah Mazaherpour 《先进技术聚合物》2019,30(11):2860-2871
In this study, a unique magnetic, pH, and thermo‐responsive hydrogel nanocomposite was synthesized via surface reversible addition fragmentation chain transfer (RAFT) copolymerization of acrylic acid (AA) and N‐isopropyl acrylamide (NIPAM) in the presence of magnetic β‐cyclodextrin (β‐CD). The nanocomposite demonstrated a pH‐responsiveness behavior at pHs 3 and 9. Moreover, swelling behaviors of nanocomposite were measured in solutions with various temperatures. Furthermore, the nanocomposites exhibited high swelling capacity by applying an external magnetic field because of the presence of Fe3O4 nanoparticles in the polymer structure. Besides, the doxorubicin (DOX) loading and releasing behaviors of the hydrogel nanocomposites were studied because of the stimuli‐responsive properties of the synthesized carriers. The adsorption of DOX obeyed a pseudo‐second‐order model and fitted well to the Langmuir isotherm model with the maximum adsorption capacity uptake of 291 mg g?1. In conclusion, the hydrogel nanocomposites were found to be as potential nanocarriers for use in controlled release applications. 相似文献
69.
Davood Raoufi Hamid Reza Fallah Amir Sayid Hassan Rozatian 《Applied Surface Science》2008,254(7):2168-2173
In this work, we developed the multifractality and its formalism to investigate the surface topographies of ITO thin films prepared by electron beam deposition method for various annealing temperatures from their atomic force microscopy (AFM) images. Multifractal analysis shows that the spectrum width, Δα (Δα = αmax − αmin), of the multifractal spectra, f(α), can be used to characterize the surface roughness of the ITO films quantitatively. Also, it is found that the f(α) shapes of the as-deposited and annealed films remained left hooked (that is Δf = f(αmin) − f(αmax) > 0), and falls within the range 0.149-0.677 depending upon the annealing temperatures. 相似文献
70.
H. Maleki-Ghaleh M.S. Shakeri Z. Dargahi M. Kavanlouei H. Kaveh Garabagh E. Moradpur-Tari A. Yourdkhani A. Fallah A. Zarrabi B. Koc M.H. Siadati 《Materials Today Chemistry》2022
The optical and electronic properties of molybdenum (Mo) doped rutile TiO2 prepared by the mechanochemical method were studied both experimentally and using density functional theory (DFT). The synthesized nanoparticles were characterized by XRD, TEM, EDS-MAP, and XPS. The XRD results showed the successful incorporation of Mo in the rutile crystal lattice. High-resolution TEM images illustrated a decreasing trend in the (110) d-spacing for samples doped up to 3 at%. The shift toward higher binding energies in the XPS spectra was due to the higher oxidization tendencies of Mo5+ and Mo6+ substituted in Ti4+ sites. The optical behavior of samples was examined by UV–Vis and photoluminescence spectroscopy. The bandgap energy value of rutile was reduced from 3.0 eV to 2.4 eV by 2 at% Mo doping. The DFT calculations showed a reduction of bandgap energy value of rutile to 2.35 eV with 2 at% Mo, which is in harmony with the experimental results. The creation of energy states below the conduction band because of Mo doping was identified as the reason for reducing the bandgap energy and photoluminescence emission of rutile. 相似文献