نتایج جستجو برای: microwave assisted
تعداد نتایج: 176049 فیلتر نتایج به سال:
SnO nanoparticles were synthesized using microwave–assisted hydrothermal method. It was noticed that at 300 and 600 watt microwave power, SnO formed and remained in the tetragonal phase. At 900 watt, SnO2 started appearing and a mixture of SnO and SnO2 phases coexisted. The particle size varied from ~2 to ~13 nm at 300 to 900 watt radiation power. The UV-V absorption spectra showed the excitoni...
In this paper, synthesis of the flower-like zinc oxide was performed using microwave assisted dicationic ionic liquid [mmp(im)2 ]Br2 . The polycrystalline flower-like zinc oxide nanostructure was obtained when a suitable mole ratio (ionic liquid /zinc acetate) and short duration microwave was used. X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectra w...
Substituted 2, 4- diphenyl quinolines were synthesized by a multicomponent domino reaction of anilines, aldehydes and terminal aryl alkynes. The synthetic pathway involves the formation of an imine, followed by the intermolecular addition of an alkyne to the imine. This intermediate immediately undergoes ring closure and oxidative aromatization. The reaction is catalyzed by natural kaolin, a st...
In order to enhance the catalytic performance of SAPO-34 catalyst for the reaction of methanol to olefins (MTO), ultrasonic and microwave-assisted aging method were employed in static hydrothermal method to synthesize nano-sized SAPO-34. The effects of the application of this method on the chemical composition, morphology, surface area and total acidity of SAPO-34 were characterized by XRD, FE-...
The broad bandwidth and low loss offered by modern photonics have led to an ever-increasing interest in the design and implementation of photonically assisted solutions for the generation, processing, control and distribution of microwave signals, an area called microwave photonics. In this article, a tutorial on microwave photonics is presented with an emphasis on optical generation of microwa...
perlite or pearl stone is a natural glass which has formed by rapid cooling of viscous lava or magma. perlite is mainly composed of silica, aluminum, potassium and sodium. in this experiment, perlite was used as a low-cost source of si and al to synthesis of sodalite zeolite using the alkaline hydrothermal treatment. a statistical taguchi design of experiments was employed to evaluate the effec...
Recent experimental results regarding a two-dimensional electron gas subjected to microwave radiation reveal that magnetoresistivity, apart from presenting oscillations and zero resistance states, can evolve to negative values at minima. Here the authors present a theoretical model which explains the transition from zero resistance states to absolute negative conductivity in terms of multiphoto...
A single-cavity microwave heating system has been designed and fabricated for microwave-assisted extraction of carrageenans from seaweed. The system comprises a single mode (TE101) waveguide fitted with power and temperature controls, together with a continuous-flow-recycle reactor operating at atmospheric pressure. The system has been tested by extraction of E. cottonii and E. spinosum in aque...
A rapid and efficient microwave-assisted solid-phase synthesis method is described for the preparation of the nonapeptide WDTVRISFK, using conventional Fmoc/Bu(t) orthogonal protection strategy. The synthesis protocol is based on the use of cycles of pulsed microwave irradiation with intermittent cooling of the reaction during the removal of the Fmoc protecting group and during the coupling. Th...
The intensive research on ferroelectric electron-emission mechanisms in the last decade has resulted in a wide understanding of the physics and characteristics of this plasma-assisted electron source. Nevertheless, practical devices employing this cathode were hardly introduced. In this experimental study, a high-repetition-rate microwave oscillator based on a ferroelectric electron gun has bee...
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