the fullerene structures of c20cage and bowl,c20h10 and their n-doped structures as c20cage nh,c20bowl nh, c20h10nh, c20h10n and their isomers are optimized using the mpw1pw91/6-31g level of the theory. magnetic shielding tensors of 14n and 13c atoms are calculated by the same level of the theory. results show that doping an n atom on fullerenes affects differently on the chemical shielding of ...

objective(s): first-principles calculations have been carried out to investigate the interaction of aspirin molecule with nitrogen-doped tio2 anatase nanoparticles using the density functional theory method in order to fully exploit the biosensing capabilities of tio2 particles. methods: for this purpose, we have mainly studied the adsorption of the aspirin molecule on the fivefold coordinated ...

In a recent paper, Bourchard et al. [1] proposed the block sum transformation, a method intended as an alternative to the discrete Fourier transform (DFT), with application to the analysis of excited vibrations of linear systems. In this note, we mention the existence of a number of alternative algorithms for the computation of the DFT, and show that the block sum transformation is equivalent t...

This paper gives a summary of basic concepts of density-functional theory (DFT) and its use in state-of-the-art computations of complex processes in condensed matter physics and materials science. In particular we discuss how microscopic growth parameters can be determined by DFT and how on this basis macroscopic phenomena can be described. To reach the time and length scales of realistic growt...

In this paper, we propose a nonuniform DFT based on nonequispaced sampling in the frequency domain. It is useful to detect some specific frequencies such as in DTMF which is composed on two different frequencies, main (fundamental) frequency component among lots of harmonics, and feature detection from noisy signals. Some trials for nonuniform data processing via DFT are discussed and resamplin...

Density Functional Theory (DFT) which is based on quantum mechanics theory has been broadly used to compute the energy and the structure of molecules and solids. However, the DFT method is limited when running calculations for a large system and only thousands of atoms can be solved. Alternatively, Molecular Dynamics (MD) simulation can be used to investigate the properties of the atomic system...

The Fast Fourier Transform (FFT) is an efficient computation of the Discrete Fourier Transform (DFT) and one of the most important tools used in digital signal processing applications. Because of its well-structured form, the FFT is a benchmark in assessing digital signal processor (DSP) performance. The development of FFT algorithms has assumed an input sequence consisting of complex numbers. ...

The efficacy of electrical defibrillation is considered to be related to the autonomic status. In search of a possible adjunct to enhance the therapeutic performance of an implantable cardioverter-defibrillator. we investigated whether parasympathetic manipulation by cervical vagal nerve stimulation (VNS) increases defibrillation efficacy. The effects of VNS on transcardiac defibrillation thres...

In this paper, we propose a new family of perfect reconstruction (PR) complex filter banks, named interleaved discrete Fourier transform modulated filter banks (Interleaved DFT-FBs). In the filter banks, the analysis filters are generated by interlaced exponential modulating two different analysis prototype filters, and the synthesis filters are generated by two different synthesis prototype fi...

We investigate the isomerization enthalpy of the Dihydroazulene/Vinylheptafulvene (DHA/VHF) molecular photoswitch system derivatives using electronic structure calculation methods including Density Functional Theory (DFT), Quantum Monte Carlo (QMC) and Coupled Cluster (CCSD(T)). Recent efforts have focused on tuning the isomerization enthalpy of the photoswitch for solar thermal energy storage ...