نتایج جستجو برای: free synthesis
تعداد نتایج: 902857 فیلتر نتایج به سال:
A cell-free protein-synthesizing system derived from rabbit reticulocytes is described which is dependent on the addition of transfer RNA for the translation of endogenous hemoglobin messenger RNA. Product analysis indicates that the system is active in the initiation of new chains. When hemoglobin is synthesized in the presence of a limiting amount of tRNA, there is a 50% decrease in (Y chain ...
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...
Nowadays green synthesis of metal nanoparticles is a developing area of research. In this study, titanium dioxide nanoparticles were biosynthesized using an aqueous solution of Echinacea purpurea herba extract as a bioreductant. This is novel and interesting method for synthesis of TiO2 nanoparticles. The prepared titanium dioxide nanoparticles were characterized using ultraviolet–visible spect...
a practical and green method for the synthesis of 5h-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3'-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (csa) under solvent-free conditions at 100 °c is described. the significant features of this pro...
due to the limiting workspace of parallel manipulator and regarding to finding the trajectory planning of singularity free at workspace is difficult, so finding a best solution that can develop a technique to determine the singularity-free zones in the workspace of parallel manipulators is highly important. in this thesis a simple and new technique are presented to determine the maximal singula...
A water soluble, Bronsted acid, 5-sulfosalicylic acid as an efficient organocatalyst was used for the synthesis of physiologically active 2-substituted benzimidazole derivatives from o-phenylenediamine and aromatic aldehydes in ethanol at reflux condition. Cost-effectiveness, use of non-hazardous solvents, metal free and commercially available catalyst, single-step, environmentally fri...
a convenient and efficient one-pot four-component synthesis of 1, 2, 4, 5-tetrasubstituted imidazoles using nano tio2 as a recyclable catalyst is reported. the results show that the methodology has several advantages such as low loading of catalyst, excellent yield, short reaction time, operational simplicity and solvent-free conditions.
molybdate sulfuric acid (msa) has been prepared and used as catalyst for the biginelli synthesis of some quinazolinones/thiones under solvent-free conditions. the catalyst loading is low and it shows recyclability. this method has advantages such as avoidance of the organic solvents, high yield of pure products, short reaction times and operational simplicity.
this study investigated the impact of explicit instruction of morphemic analysis and synthesis on the vocabulary development of the students. the participants were 90 junior high school students divided into two experimental groups and one control group. morphological awareness techniques (analysis/synthesis) and conventional techniques were used to teach vocabulary in the experimental groups a...
Graphene films were fabricated over synthesized MCM-41 nanocatalyst by chemical vapordeposition method, and the reaction was carried in atmospheric pressure at 750˚C. Acetylenegas used as a carbon precursor and the synthesis reaction took place in hydrogen atmosphere.Mesoporous MCM-41 was synthesized at room temperature, using wet chemical method. Thesynthesized metal free catalyst was characte...
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