نتایج جستجو برای: uniform theory of diffraction
تعداد نتایج: 21233973 فیلتر نتایج به سال:
one of the most important number sequences in mathematics is fibonacci sequence. fibonacci sequence except for mathematics is applied to other branches of science such as physics and arts. in fact, between anesthetics and this sequence there exists a wonderful relation. fibonacci sequence has an importance characteristic which is the golden number. in this thesis, the golden number is observed ...
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...
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...
This paper presents the shaping optimization of an S-band cylindrical offset reflector antenna with cosecant-squared radiation pattern in elevation plane. The cross section of the antenna is mathematically modeled by a polynomial function and optimized by the genetic algorithm to obtain the desired pattern for both TE and TM polarizations. The physical optics method together with the uniform th...
In this paper, we propose a 3D model to characterize the field scattered by an urban area, which is composed of a group of buildings, for both monostatic and bistatic radar configurations. This model is based on a ray-tracing technique combined with the Uniform Theory of Diffraction (UTD). It is useful not only in elucidating mechanisms of ray propagation through the observed area, but also in ...
in this thesis, using concepts of wavelets theory some methods of the solving optimal control problems (ocps). governed by time-delay systems is investigated. this thesis contains two parts. first, the method of obtaining of the ocps in time delay systems by linear legendre multiwavelets is presented. the main advantage of the meth...
from 1950s onward, new theories and critical approaches burgeoned across humanities. these theories were context-oriented; as a result, the analysis of discursive practices gained significance. thus, social, political, historical and cultural discourses that have been hitherto marginalized and considered inferior to literary texts, were introduced as important texts to be analyzed by critics. o...
Suitable stable channel design and optimization of river geometry can reduce cost of projects. The regime theory provides the possibility of empirical and semi-empirical investigations of stable channel design in which erosion and sediment transport are in equilibrium. The objective of this research is an investigation and a comparison of the influence of uniform and non-uniform flows on the pr...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید