نتایج جستجو برای: cyclization of time
تعداد نتایج: 21267950 فیلتر نتایج به سال:
cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...
vocabulary as a major component of language learning has been the object of numerous studies each of which has its own contribution to the field. finding the best way of learning the words deeply and extensively is the common objective of most of those studies. however, one effective way for achieving this goal is somehow neglected in the field. using a variety of activities such as games can r...
short story as an important literary genre in the recent decade is focused by many of young writers and literary critical with searching structure, content , artistic techniques and cognitive phenomenon of these works , we can show quantity of using some parts of storied literature from new literal techniques of the word and also we can show the usage of native, cultural and social foundation...
a semi-empirical mathematical model for predicting physical part of ignition delay period in the combustion of direct - injection diesel engines with swirl is developed . this model based on a single droplet evaporation model . the governing equations , namely , equations of droplet motion , heat and mass transfer were solved simultaneously using a rung-kutta step by step unmerical method . the...
today the image of a permanent skeletal space of cities affected by some forces or mechanisms is put in time with social-economic development and while imposes a new face and perspective to physical anatomy of cities, and prepares field to changes in content and social- economic structures of cities too. simultaneously with quitting villages in order to settle in cities by villagers, the phen...
A simple and ecofriendly method was developed for the synthesis of arylmethylene[bis(5,5- dimethyl-3-hydroxy-2-cyclohexene-1-ones)] from the reaction of 5,5-dimethylcyclohexane- 1,3-dione and aromatic aldehydes in an aqueous media without any catalyst via Knoevenagel condensation followed by rapid Michael addition. No cyclization product was down to convert these enolic forms to xanthene deriva...
3-Mercapto-1,2,4 benzotriazine (1) was methylated by methyl iodide in the presence of base to afford 1,2-dihydro-3-methyhercapto-1, 2,4 benzotriazine (2). The latter was reacted with hydrazine hydrate to give the corresponding 3-hydrazine derivative (3). Compound (3) on condensation with phenacyl bromide gave 3- phenacyl hydrazino l,2,4-benzotriazine (4). PPA cyclization of the ketone (4) ...
abstract the present study deals with a comparison between reactive and pre-emptive focus-on-form in terms of application and efficiency. it was conducted in an intermediate english class in shahroud. 15 male learners participated in this research and their age ranged from 18 to 25. a course book, new interchange 3, and a complementary book were used. every session the learners gave lectures o...
due to extraordinary large amount of information and daily sharp increasing claimant for ui benefits and because of serious constraint of financial barriers, the importance of handling fraud detection in order to discover, control and predict fraudulent claims is inevitable. we use the most appropriate data mining methodology, methods, techniques and tools to extract knowledge or insights from ...
the community dynamics of aquatic coleoptera(insecta)in one of the spring-stream habitats of bammo national park in fars province called cheshmeh-ye-ghanbari is studied as a pilot project and model for acquaintance with and furthering the biodiversity studies on fauna of iran. sixteen species-populations out of nineteen of this community were already identified for their taxonomy and for thei...
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