نتایج جستجو برای: so it may be changed by environmental changes today
تعداد نتایج: 9587290 فیلتر نتایج به سال:
in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...
the ability of composing a coherent and extended piece of writing in second language is considered as a fundamental factor to convey information and ideas of learners through the academic issues. although learners may achieve a perfect academic writing skill through assigning the l2 tasks in content based instruction, but demonstration of their abilities may be related to their ability in l1 es...
abstract environmental factors including salinity and temperature can affect the physiology and performance of the growth of fish, so many of internal organs such as gill may be showed wide range of morphological and functional changes. fingerling common carp were exposed for 21 days in groups at 20, 25 and 30°c and three salinity levels 0, 5 and 10ppt. histological changes of gills tissue of c...
Natural areas have been reserved for thousands of years. However, the reasons for reservation have changed with time. Natural areas management objectives have changed from personal/individual human needs to environmental protection. Unlike old protected areas, new protected areas have multiple management objectives. The management objectives changed from protection for now to protection for the...
in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...
the present study was an attempt to determine the types of motivation and levels of foreign language learning anxiety among efl students studying at azad and state universities in kermanshah and to determine the relationship between these two factors and language proficiency and gender. to this end, the foreign language learning motivation scale, by deci and ryan )1985(, were administered to 12...
One of the sensitive systems in geomorphology is coastal systems in which the change in them is fast due to the collision of two dynamic environments of sea and land.Because Coastal lines can record evidence of geomorphological alterations. Due to several reasons like environment changes, global warming, issues regarding human activities and etc. studies and quantitative measurements from perio...
today, urbanization (living at apartments) phenomenon as the most common type of residence of cities has been changed so that mainly reflects the chaos in this area. too much attention paid to economic indicators compromised the balance in the housing sector and created a new type of buildings. the occurred changes indicate ignoring cultural characteristics, less attention paid to cultural conc...
abstract: mineral scaling in oil and gas production equipment is one of the most important problem that occurs while water injection and it has been recognized to be a major operational problem. the incompatibility between injected and formation waters may result in inorganic scale precipitation in the equipment and reservoir and then reduction of oil production rate and water injection rate. ...
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