نتایج جستجو برای: relative density and microstructure

تعداد نتایج: 16894759  

In this research study, the effects of aluminum nitride (AlN) additive on the densification behavior and microstructure development of titanium diboride (TiB2) based ceramic matrix composite were investigated. In this way, a monolithic TiB2 ceramic and a TiB2–5 wt% AlN ultrahigh temperature ceramic composite were fabricated by spark plasma sintering (SPS) proces...

In this study, WC–20 wt.% equiatomic (Fe,Co) powder mixture was milled in a planetary ball mill. The effects of different milling time (15 min, 5h, 10h, and 25 h) and sintering temperatures on the microstructure and mechanical properties of this equi-Fe substituted cermet were investigated. The structural evolution and the crystallite size changes of the powders during milling were monitored by...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی و علوم دریایی 1388

this research was conducted in two protect and destroy region in the middle zagros, in illam province. in order to identification of ecological species group and evaluate density of regeneration, effect of many factors such as protection, vegetation, physiographic factors, physical and chemical properties of soil in study locations were studied. to achieve these purpose number of 54 plots using...

پایان نامه :وزارت علوم، تحقیقات و فناوری - پژوهشگاه دانشهای بنیادی (مرکز تحقیقات فیزیک نظری و - پژوهشکده علوم نانو 1392

among the low–dimensional allotropes of carbon, nanotubes and graphene have attracted very much attention from nano–science and nanotechnology specialists. they have been proposed as building blocks in nanometer device engineering. however, these structures are not defect–free. in this thesis, we focused on defective carbon nanotubes and graphene, and studied the effect of couple of very common...

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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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیخ بهایی - دانشکده زبانهای خارجی 1391

simplification universal as a universal feature of translation means translated texts tend to use simpler language than original texts in the same language and it can be critically investigated through common concepts: type/token ratio, lexical density, and mean sentence length. although steps have been taken to test this hypothesis in various text types in different linguistic communities, in ...

Alumina-Mullite-Zirconia ceramic composites were prepared by reaction sintering of alumina, zircon mixture and the sintering aids of magnesia and titania at temperatures of 1400 and 1600 C for 2 hours. The development of different phases and microstructures of the composites were analysed to assess the relative influence of the additives on the formation of alumina-zirconia-mullite compos...

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...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد یزد - دانشکده شیمی 1392

in this study, a simple, rapid and selective method was developed for the determination of dexamethasone. the proposed method is based on inhibitory effect of dexamethasone on the oxidation of orange-g by bromate in sulfuric acid media. the reaction was followed spectrophotometrically at 478.5 nm (?max). under optimum experimental conditions, (72.6 ?mol l-1 of orange-g, 0.76 mol l-1 of h2so4, 0...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده علوم پایه 1390

abstract in this study, we synthesized a novel template polymer by using methacrylic acid (mma) as functional monomer, ethylene glycol dimethacrylate(egdma) as cross linker, 2,2-azobisisobutyronitrile (aibn) as initiator and olanzapine as targeted molecule in the presence of chloroform and acetonitrile as solvent. the products have been characterized and confirmed by (chn)elemental analysis,...

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