نتایج جستجو برای: temperature synthesis
تعداد نتایج: 844315 فیلتر نتایج به سال:
we report the direct soft chemical synthesis and characterization of a family of face centered cubic (fcc) and partially ordered face centered tetragonal (fct) fept nanoparticles (nps) suitable for biomedical applications. both fcc and partially ordered fct-fept nps are synthesized by employing a simple polyol method. by using polyvinyl pyrolidone (pvp) as a stabilizer in various ratios during ...
penicillin g acylase from e. coli ta1 was immobilized by cross-linked enzyme aggregates (clea), a new method for immobilization. this biocatalyst and commercial immobilized penicillin g acylase (pga-450) were used to study the effect of ph, temperature and substrate concentration on the synthesis of ampicillin from phenyl glycine methyl ester (pgme) and 6-aminopenicillanic acid (6-apa). compare...
silica-bonded n-propyldiethylenetriamine sulfamic acid (spdtsa) is employed as a recyclable heterogeneous solid acid catalyst for the synthesis of benzopyrano[2,3-d]pyrimidines through one-pot condensation reaction of salicylaldehydes, malononitrile and secondary amines at room temperature under solvent-free conditions. spdtsa showed much the same efficiency when used in consecutive reaction ...
in the present work, the synthesis of barium hexaferrite (bafe12o19) nanoparticles in thepresence of a large excess amount of oh− anions by the hydrothermal method in the presence and absence of surfactants such as sodium dodecyl benzene sulfonate and triton x-114 was reported. the optimized temperature in the absence of surfactant was determined (200 °c) and then barium hexaferrite nanoparticl...
An efficient one pot multi component synthesis of 1, 4-Polyhydroquinoline derivatives through unsymmetrical Hantzsch reaction using lanthanum chloride heptahydrate (LaCl3.7H2O) from an aromatic aldehyde, ethyl acetoacetate, dimedone and ammonium acetate as a nitrogen precursor in ethanol at room temperature is described. In the present work we report lanthanum chloride heptahydrate remarkably n...
nano sulfated titania was tested as solid acid heterogeneous catalyst for the synthesis of 4-(trifluoromethyl) coumarin and coumarin derivatives under solvent-free condition. factorial design evidenced a positive effect of reaction temperature, amount of catalyst, and solvents. this nano-sized sulfated titania has been prepared by a sol-gel hydrothermal process. the prepared sulfated titania s...
polypyrrole is one of the most useful conductive polymers, but green synthesis of this polymer has been restricted until now. the objective of the present paper is green synthesis of nano polypyrrole (ppy) by oxidative polymerization using urea-hydrogen peroxide. it was found that conductivity and morphology of polypyrrole are highly dependent on the reaction conditions such as the molar ratio ...
nanosized al2o3 powder is synthesized by thermal metal organic chemical vapor deposition (mocvd)combined withplasma. the effects of reaction temperature, pressure, al(ch3)3 (tma) concentration and reactant gases (co2 and o2) on the characteristics of the synthesized al2o3 powders are investigated. the experimental results demonstrate that very fineal2o3 powders with mean particle size of about ...
the catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reaction of azomethine ylides, derived from isatin, with electron-deficient dipolarophilewas described. the process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–cu(...
The effects of temperature on protein metabolism have been studied mostly with respect to protein synthesis. Temperature generally has a parabolic effect on protein synthesis with a maximum rate being observed at optimal growth temperature. The effect of temperature on protein degradation is poorly understood. The 20S proteasome is mainly responsible for the degradation of short-lived and oxida...
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