نتایج جستجو برای: surface structure
تعداد نتایج: 2094622 فیلتر نتایج به سال:
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...
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...
Combinatory Categorial Grammar (CCG) was originally advanced as a theory relating coordination and relativization. The claim was that these constructions can be analysed at the level of surface grammar, without rules of movement, deletion, passing of slash-features, or the syntactic empty category Wh-trace. Instead, CCG generalizes the notion of grammatical constituency to cover everything that...
abstract: the present thesis includes ; one preface and 11speeches , that each speech considered in different researches . the prefact part , studied grammer back ground , the first speech considered a brief description about grammatical credits . the second speech considered the different typs of sentences , from structure and meaning points of view . the third speech considered the verb es...
a new base isolation method for reducing the destructive effect of earthquake is proposed in this method mushroom shaped basements are used under structures as base isolation. these basements have spherical surface and are located on foundations. basements have pinned arms that are connected. when the length of the arm is less then the radius of spherical surface, the action of them is similar ...
چکیده ندارد.
single-walled carbon nanotubes (swcnt) and multi-walled carbon nanotubes(mwcnt) were melt-blended with polyvinylidene fluoride (pvdf).ft-ir technique revealed that swcnt has insignificant effect on the crystalline structure of pvdf and at 3wt% modification only 14% beta crystal isformed. this observation was accounted for by the chair structure of swcnt. in mwcnt nancomposites it was found that...
We develop a general approach that uses holomorphic 1-forms to parameterize anatomical surfaces with complex (possibly branching) topology. Rather than evolve the surface geometry to a plane or sphere, we instead use the fact that all orientable surfaces are Riemann surfaces and admit conformal structures, which induce special curvilinear coordinate systems on the surfaces. Based on Riemann sur...
In this work, SiO2 –ZrO2 mixed oxides was prepared by the polymeric sol–gel route. The characterization of pore structure, which determines the permeation process of membrane, is of great importance. So far, most investigations have focused on such pore structure as specific surface area and pore size distribution, but the surface fractal, the important parameter reflecting the roughness of por...
wire-brushing is used for different purposes such as removing metal surfaces oxides, increasing surface brightness, improving fatigue properties and surface activation before coating. the wire-brushing severely scratches and stirs the metals in the surface layers, so that complicated metal flow gives rise to very large amount of plastic strain and increases dislocation density of the surface la...
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