نتایج جستجو برای: the 3 1
تعداد نتایج: 16681489 فیلتر نتایج به سال:
در این پژوهش یک روش ساده برای سنتز مشتقات 3،1- دی انولات از 3،1- دی کتون ها در استونیتریل به عنوان حلال با استر های غیر اشباع دی متیل استیلن دی کربوکسیلات (dmad)، دی اتیل استیلن دی کربوکسیلات (dead)، دی ترشیو بوتیل استیلن دی کربوکسیلات (dtad)، گزارش شده است. به محلول ترکیب 3،1- دی کربونیل در حلال استونیتریل، استر غیر اشباع و باز k2co3 به مدت مناسب اضافه می شود. نمک حاصل توسط (me)3sicl هیدرولیز ...
abstract this study is an attempt to determine the effect of nano- technology education on science lesson for fifth grade in primary school in the city of kermanshah. this research is experimental and is conducted in the from of pre-test and post- test for the control group. an achievement test was administered to determine the rate of learning in the students. the research is an applied one. ...
this study examines the effetivenss of task-based activities in helping students learn english language structures for a better communication. initially, a michigan test was administered to the two groups of 52 students majoring in english at the allameh ghotb -e- ravandi university to ensure their homogeneity. the students scores on the grammar part of this test were also regarded as their pre...
introduction: diabetes mellitus is an growing national and international public health concern. the number of people affected by diabetes in world by 2030 will be 69% in developing countries. regular physical activity plays a key role in the management of type 2 diabetes melitus, particularly glycemic control. it has been recommended that peoples with type 2 diabetes participate in moderate-int...
determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...
We investigate the long-term behavior of solutions of the difference equation[ x_{n+1}=x_{n}x_{n-3}-1 ,, n=0 ,, 1 ,, ldots ,, ]noindent where the initial conditions $x_{-3} ,, x_{-2} ,, x_{-1} ,, x_{0}$ are real numbers. In particular, we look at the periodicity and asymptotic periodicity of solutions, as well as the existence of unbounded solutions.
power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...
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