نتایج جستجو برای: surface
تعداد نتایج: 635383 فیلتر نتایج به سال:
surface-piercing propellers (spps) have been widely used in high speed craft due to some desirable features such as high efficiency, omission of resistance of equipment attached to the propeller and proper functioning of cavitation. unlike the submerged propellers, theoretical methods have no significant application on simulation of sppsbecause of problems related to modeling of these propeller...
a novel acrylic acid-functionalized fe3o4 magnetic nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperacid in chemical transformations. the structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (tem), thermogravimetric analysis (tga), and ft-ir...
this is an original study on the effect of a polyisobutylene – polydimethylsiloxane (pibpdms) block copolymer modifier used as an interfacial active agent on the dynamics behaviour of single newtonian drops suspended in a polyisobutylene (pib) newtonian matrix. the results were divided in two sections. the first part included the experiments carried out on the non-modified and 2% block cop...
in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...
در این پایان نامه با استفاده از روشهای نظری تابعی چگالی (dft) و خوشه جفت شده (ccsd(t)) مسیرهای ممکن برای واکنشch4 با rh2+ با چندگانگی اسپینی 2، 4 و 6 مورد بررسی قرار گرفته است. پژوهش های انجام شده، روش های محاسباتی از جمله روشهای به کار رفته در این پژوهش و برخی نکات وابسته به آنها و چگونگی بدست آوردن ساختارهای حالت گذار با استفاده از روشrelaxed surface scan شرح داده شده اند. برای محاسبات بهینه ...
a superhydrophobic aluminum surface was fabricated through an enhanced low-cost approach and the effects of several relevant factors on static contact angle and sliding angle were investigated. first, the operating parameters including the etching time as well as the reaction time and temperature were varied. next, the so-called chemical factors including three different fatty acids and five di...
this paper presents the findings of experimental investigations into the effects of cutting speed, feed rate, depth of cut and approach angle on the machinability of titanium (grade-5) alloy. also the comparison for the two different cutting materials inserts polycrystalline diamond (pcd) and cubic boron nitride (cbn) with similar tool geometry for similar machining parameters is also carried o...
this study focuses on tracing the clearly defined elements of magic realism in toni morrison’s song of solomon as an illustrious african american example of the mode. magic realism is a fictional technique that combines fantasy with raw physical reality in a search for truth beyond that available from the surface of everyday life. toni morrison, as a distinguished african-american practitioner ...
زمینه و هدف: استرس ناشی از پلیمریزه شدن کامپوزیت تمایل به ایجاد فضاهایی در سطح بین دندان و ترمیم دارد. این امکان وجود دارد که surface sealantها مشکلات مربوط به ریزنشت در نواحی مارجینال را کاهش و یا از ایجاد آنها جلوگیری کنند. هدف این مطالعه، بررسی تاثیر دو نوع surface sealant (fortify and optiguard) بر ریزنشت ترمیم های کلاس v کامپوزیتی بود.روش بررسی: 23 دندان مولر سالم جمع آوری و در سطوح باکال ...
background: there are many genera of free-living amoeba in the environment, but members of only four genera ( naegleria , acanthamoeba , balamuthia and sappinia ) have an association with human infection. water, soil and air are main sources of infective types of these pathogenic organisms for human. methods: totally, 30 samples were collected from the surface water sources of shiraz city, the ...
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