نتایج جستجو برای: dielectric

تعداد نتایج: 39217  

Journal: :جنگل و فرآورده های چوب 0
کژال مرادیان کارشناس ارشد صنایع خمیر و کاغذ، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران محمد آزادفلاح استادیار، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران امیر عباس شایگانی اکمل استادیار، گروه مهندسی برق، دانشکدة مهندسی برق و کامپیوتر، دانشگاه تهران، تهران، ایران علی عبدالخانی دانشیار، گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران

the oil-paper insulation is a type of an inexpensive combination insulation system in oil-filled power transformers. in this study the dielectric and strength properties of canola oil and mineral oil impregnated hand-sheet papers were investigated. all hand sheets were made of unbleached bagasse soda pulp with two different freeness levels of 200 ± 25 ml, csf and 400± 25 ml,csf. after drying th...

Journal: :مهندسی بیوسیستم ایران 0
محمود سلطانی فیروز کارشناسی ارشد، دانشگاه تهران رضا علیمردانی استاد، دانشگاه تهران محمود امید استاد، دانشگاه تهران

grading of agricultural products has always been a subject of research by scientists. one of the criteria to be chosen for grading of fruits is the fruit's level of ripeness. different methods have been employed to assess the status of fruit ripeness some of which are destructive and others are not so. in this research, a noninvasive capacitive method was used to estimate the ripeness leve...

Journal: :journal of nanostructures 2014
a. hayati a. bahari

some issues; leakage, tunneling currents, boron diffusion are threatening sio2 to be used as a good gate dielectric for the future of the cmos (complementary metal- oxide- semiconductor) transistors. for finding an alternative and novel gate dielectric, the nio (nickel oxide) and pva (polyvinyl alcohol) nano powders were synthesized with the sol-gel method and their nano structural properties w...

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Bismuth titanate ceramic has been attracted as a lead-free ferroelectric due to its high Curie temperature in high temperature applications as well as high frequency applications. In this study, the effect of niobium oxide as an additive on the microstructure and dielectric properties of bismuth titanate ceramic was investigated. For this purpose, niobium oxide was added to bismuth titanate, sy...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

Recently, photonic crystals doped with liquid crystal (LC) material havegained much research interest. In this article new ternary one-dimensional photoniccrystal introduced and studied. The liquid crystal layer of 5CB and 5PCH is sandwichedby two dielectric layers. For the first time, we use four structures SiO2/UCF35/CaF2,SiO2/5CB/CaF2, NFK51/UCF35/NPSK53 and NFK51/5CB/NPSK53. The effect ofte...

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In the present work, the effect of sintering parameters including sintering temperature, soaking time, and heating rate on densification, microstructure, and dielectrical properties of bismuth titanate (Bi4Ti3O12) ceramics were investigated. Bismuth titanate was synthesized by the solid state method and titanium oxide and bismuth oxide used as raw materials. X-ray diffraction (XRD) indicated, p...

Journal: :physical chemistry and electrochemistry 0

experimental results of dielectric investigations for binary mixtures of 2, 3-butanediol, 2, 3-bd, in2-ethyl-1-hexanol, 2eh, were reported for various mole fractions and temperatures (298.2-308.2) kand they were used to calculate dielectric parameters such as kirkwood correlation factor, excesspermittivity and bruggeman parameter. these parameters were used to carry out temperaturedependent die...

زرگر شوشتری, مرتضی, سلطانی, میترا, موسوی قهفرخی, سید ابراهیم,

In this paper, the chromium doped spinel zinc ferrite nanoparticles were synthesized by using of glycine as a fuel with microwave combustion method. After preparing the samples  with x = 0.0, 0.5, 1.0, 1.5, 2.0, the electromagnetic and electrical properties such as dielectric constant, ac conductivity, dielectric loss factor (and Curie temperature were investigated. According to the results, in...

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