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排序方式: 共有234条查询结果,搜索用时 11 毫秒
61.
Debasish Borah Neeharika Das Nirmalendu Das Ankita Bhattacharjee Pampi Sarmah Kheyali Ghosh Madhurya Chandel Jayashree Rout Piyush Pandey Narendra Nath Ghosh Chira R. Bhattacharjee 《应用有机金属化学》2020,34(5):e5597
A facile, convenient and green method has been employed for the synthesis of silver nanoparticles (AgNPs) using dried biomass of a green alga, Chlorella ellipsoidea. The phytochemicals from the alga, as a mild and non-toxic source, are believed to serve as both reducing and stabilizing agents. The formation of silver nanoparticles was confirmed from the appearance of a surface plasmon resonance band at 436 nm and energy dispersive X-ray spectroscopy. The transmission electron microscopy images showed the nanoparticles to be nearly spherical in shape with different sizes. A dynamic light scattering study revealed the average particle size to be 220.8 ± 31.3 nm. Fourier transform infrared spectroscopy revealed the occurrence of alga-derived phytochemicals attached to the outer surface of biogenically accessed silver nanoparticles. The powder X-ray diffraction study revealed the face-centred cubic crystalline structure of the nanoparticles. The as-synthesized biomatrix-loaded AgNPs exhibited a high photocatalytic activity for the degradation of the hazardous pollutant dyes methylene blue and methyl orange. The catalytic efficiency was sustained even after three reduction cycles. A kinetic study indicated the degradation rates to be pseudo-first order with the degradation rate being 4.72 × 10−2 min−1 for methylene blue and 3.24 × 10−2 min−1 for methyl orange. The AgNPs also exhibited significant antibacterial activity against four selected pathogenic bacterial strains. 相似文献
62.
Abhishek Upadhyay Vinay K. Singh Rahul Dubey Narendra Kumar L.K. Sharma Rana Krishna Pal Singh 《Tetrahedron letters》2017,58(46):4323-4327
A highly efficient one pot, multicomponent synthesis of 4H-benzo[g]chromene and pyrano[2,3-g]chromene derivatives are reported by electrochemically stimulated condensation of an aromatic aldehyde, malononitrile and some enolizable acidic compounds in ethanol at room temperature under constant current density. By utilizing common electrode materials and a simple constant current protocol, this method is a new alternative to conventional methods. 相似文献
63.
Amit B. Rajput Subhenjit Hazra Niharika B. Krishna Pavani Chavali Sneha Datla Narendra Nath Ghosh 《Particuology》2012,10(1):29-34
An ethylene diamine tetra acetic acid (EDTA) precursor-based chemical method is reported for preparing single-phase nickel ferrite (NiFe2O4) nanopowder. The synthesized powder was characterized by thermogravimetric analysis, differential scanning calorimetric analysis, X-ray diffraction, particle size analysis and scanning electron microscopy. DC electrical resistivity and magnetic property of the synthesized NiFe2O4 were measured by using a two-probe method and a vibrating sample magnetometer respectively. The DC resistivity behaviour of the NiFe2O4 nanopowder was correlated with the change of microstructure, during sintering. This EDTA precursor-based method is capable of producing nanostructured single-phase NiFe2O4 powder at a comparatively low calcination temperature and offers the potential of a simple and cost-effective route, including the preparation of other ferrite nanoparticles. 相似文献
64.
Anuj Jakhar 《代数通讯》2018,46(1):114-118
We state a mild generalization of the classical Schönemann and Eisenstein- Dumas irreducibility criterion in ?[x] and provide an elementary proof. In the end of the paper, we also provide a concrete example of a polynomial which is irreducible by the main result of the paper but whose irreducibility does not follow from existing criteria. 相似文献
65.
Damped transient dynamic elasto-plastic analysis of plate is investigated. A finite element model based on a C
0 higher order shear deformation theory has been developed. Nine noded Lagrangian elements with five degrees of freedom per
node are used. Selective Gauss integration is used to evaluate energy terms so as to avoid shear locking and spurious mechanisms.
Von Mises and Tresca yield criteria are incorporated along with associated flow rules. Explicit central difference time stepping
scheme is employed to integrate temporal equations. The mass matrix is diagonalized by using the efficient proportional mass
lumping scheme. A program is developed for damped transient dynamic finite element analysis of elasto-plastic plate. Several
numerical examples are studied to unfold different facets of damping of elasto-plastic plates. 相似文献
66.
Mayank Pandey Girish M. Joshi Kalim Deshmukh Moumita Khutia Narendra Nath Ghosh 《Ionics》2014,20(10):1427-1433
Polyvinylidene fluoride (PVDF) and polyvinyl alcohol (PVA) composites were prepared by controlled loading of Nafion (5 to 15 wt%) by solution casting using water and dimethylformamide (DMF) as a solvent. The surface morphology of composite analyzed by atomic force microscopy (AFM) reveals the presence of Nafion ionomers. The increase in interlayer spacing of modified PVDF/PVA polymer system as a function of Nafion was detected by X-ray diffraction (XRD). The major change in Fourier transform infrared (FTIR) spectroscopy confirms the chemical bond C=O stretching around 1,700 cm?1 due to Nafion. Differential scanning calorimetry (DSC) demonstrates the thermal stability of polymer composites and the decrease in melting temperature (T m). The optimized AC conductivity (σ) of the prepared composite was evaluated by using an impedance analyzer as a function of temperature (40 to 150 °C) at constant 30-MHz frequency. The highest conductivity of 1.3?×?10?2 S m?1 was observed at 80 °C for 10 wt% of Nafion and correlated with structure, morphology and thermal properties of modified PVDF/PVA/Nafion composites. The experimental results may be useful for sensors, fuel cells and battery application domains. 相似文献
67.
Bodige S. Ravula P. Gulipalli K. Ch. Endoori S. Cherukumalli P. Koteswara Rao Chandra J. N. Narendra Sharath Seelam N. 《Russian Journal of General Chemistry》2020,90(7):1322-1330
Russian Journal of General Chemistry - A series of novel N-{2-fluoro-6-[(4,6-dimethoxy-1,3,5-triazin-2-yl)methyl]phenyl} carboxamide derivatives has been synthesized, and their molecular structures... 相似文献
68.
Varma Nimmu Narendra Naidu Challa Gangu Ramachandra Bondigalla Swamy Arnipalli Manikanta 《Journal of Analytical Chemistry》2021,76(10):1172-1181
Journal of Analytical Chemistry - A water-compatible molecularly imprinted polymer (MIP) was prepared for specific extraction of HIV-1 integrase inhibitor elvitegravir (EVG). It was prepared by a... 相似文献
69.
70.
This paper describes a special method of laser-based deposition to synthesize palladium-ceramic composite membranes. Thin film Pd was deposited on a ceramic substrate by Nd-YAG laser irradiation of coating precursor PdCl2 on γ-alumina substrate. The parameters of the laser processing technique were optimized to synthesize metal-ceramic composite membranes. The physical and chemical characteristics of Pd coated γ-alumina membranes were studied and compared with various other alumina membranes referenced in the literature. Hydrogen permeation experiments were performed in a CO + CO2 + CH4 + H2 environment under typical catalytic steam gasifier exit conditions. The Pd-ceramic composite showed good mechanical and thermal stability and resulted in a hydrogen permeability flux of about 0.061 mol/m2 s. The activation energy of the Pd membrane was found to be 5.39 kJ/mol in a temperature range of 900-1300 °F. 相似文献