polyimide/nickel oxide (polyimide/nio) nanocomposite was successfully synthesized by sol gel technique, using pyromellitic dianhydriede (pmda), 4,4-oxydianiline (oda) and n,n-dimethylacetamide (dmac) and 10 wt% nickel titanate nanopowders (nps). fourier transform infrared spectrometry (ftir), x-ray diffraction (xrd), scanning electron microscopy (sem), and vibrating sample magnetometer (vsm) we...

In this presentation we establish new bounds on functions, which have their n-th order Hankel Transform bandlimited. This class of functions is proved to be also Fourier Transform bandlimited. N-th order Hankel Transforms and the consequent bounds are important for the reconstruction in CAT, MRI (Magnetic Resonance Imaging) etc. Indeed many algorithms of modern tomography use the appropriate fo...

Obtaining a non-trivial (super-linear) lower bound for computation of the Fourier transform in the linear circuit model has been a long standing open problem for over 40 years. An early result by Morgenstern from 1973, provides an Ω(n log n) lower bound for the un-normalized Fourier transform when the constants used in the computation are bounded. The proof uses a potential function related to ...

Dirichlet series and Fourier series can both be used to encode sequences of complex numbers an , n ∈ N. Dirichlet series do so in a manner adapted to the multiplicative structure of N, whereas Fourier series reflect the additive structure of N. Formally at least, the Mellin transform relates these two ways of representing sequences. In this paper, we make sense of the Mellin transform of period...

This paper presents a novel VLSI architecture for computing the N-point discrete Fourier transform (DFT) based on a radix-2 fast algorithm, where N is a power of two. The architecture consists of one complex multiplier, two complex adders, and some special memory units. It can compute one transform sample every log2N+1 clock cycles in average. For the case of N=512, the chip area required is ab...

A fast, simple, and numerically stable transform for converting between Legendre and Chebyshev coefficients of a degree N polynomial in O(N(logN)2/ log logN) operations is derived. The basis of the algorithm is to rewrite a well-known asymptotic formula for Legendre polynomials of large degree as a weighted linear combination of Chebyshev polynomials, which can then be evaluated by using the di...

We propose a new transform coding algorithm that integrates all optimiza tion steps into a coherent and consistent framework Each iteration of the algorithm is designed to minimize coding distortion as a function of both the transform and quantizer designs Our algorithm is a constrained version of the LBG algorithm for vector quantizer design The reproduction vectors are constrained to lie at t...

В статье рассматриваются однородные функции, имеющие вид $\theta \left(\tau \right)\left|t\right|^{\alpha },$ гдепорядок однородности $\alpha >-n$, а \left(\tau\right)$ - функция на единичной сфере $S^{n-1}=\left\{t{\in}R^n, \left|t\right|=1\right\}$. При вычислении преобразования Лапласа этих функций с носителем востром конусе необходимо получить их явное представление. Это достигается сумм...