Analytic second derivatives of the energy with respect to nuclear coordinates have been developed for spin restricted density functional theory (DFT) based on the fragment molecular orbital method (FMO). The derivations were carried out for the three-body expansion (FMO3), and the two-body expressions can be obtained by neglecting the three-body corrections. Also, the restricted Hartree-Fock (R...

The implementation of OFDM transmitters typically consists of a discrete DFT matrix and a digital-to-analog (DAC) converter. Many existing results on the analysis of OFDM systems, e.g., spectral roll-off, are based on a convenient analog representation. In this paper, we show that the analog representation and the DFT-based OFDM transmitters are equivalent only in special cases. Using the analo...

Iron-based superconductors offer an ideal platform for studying topological superconductivity and Majorana fermions. In this paper, we carry out a comprehensive study of the band topology surface states number iron-based using combination density functional theory (DFT) dynamical mean-field theory. We find that strong electronic correlation Fe $3d$ electrons plays crucial role in determining su...

In this paper, we are going to discuss some fundamental aspects of the implementation of an OFDM modem for wireless indoor applications. One basic component of common OFDM systems is the computation of the DFT. Therefore, some efficient FFT algorithms like the SplitRadix and the Winograd-FFT algorithm have been implemented and their applicability for these modern communication systems has been ...

The major issue with active pharmaceutical ingredients (APIs) is their slow dissolution rate and solubility. This makes them less likely to get into the body bioavailable. About 40 % of drugs already on market 90 being made have APIs that do not dissolve well in water. To deal this problem, authors designed eutectic mixture (EMs) different (danazol, griseofulvin, mefenamic acid, tolfenamic acid...

This paper presents a comparison between Kalman filter and the running DFT for the computation of harmonics in power systems applications. The performance of both filters is compared for events like voltage dips or those in which a decaying DC component is present. The comparison considers also the presence of higher order harmonics. Key-Words: Digital filters, Harmonic analysis, Kalman filteri...

Fast computation of DFT and other popular transforms is essential in high-speed DSP applications. This paper proposes new architectures with low hardware cost and high throughput rate. The new architectures are very suitable for VLSI implementation since they are very regular and require much fewer complex multipliers compared to the recently proposed approaches. Furthermore, the same architect...

Reaction between 1,2-bis(2-hydroxyphenyl)-ethylenediamine (hpen) and methyl pyruvate gives the diaza-Cope rearrangement product with good yield and excellent stereospecificity. The product containing two chiral quaternary carbon centers is characterized by high performance liquid chromatography and X-ray crystallography. DFT computation provides insight into why the diaza-Cope rearrangement tak...

Here and hereafter T = (ti,j) n−1 i,j=0, ti,j = 1 for i − j = 0, ti,j = c 6= 0 for i − j = 1, and ti,j = 0 otherwise, x = (xi) n−1 i=0 , and b = (bi) n−1 i=0 . Note that the system is scaled so that the main diagonal is composed exclusively of ones, with no loss of generality. These systems are at the heart of problems as diverse as cubic spline and Bspline curve fitting [3], [11], precondition...

Carbon nanotubes (CNTs) and fullerenes have a lot of potential applications in nanotechnology. In the stream of efforts to exploit these nanoscale materials, the computational simulations have turned out to be powerful and efficient tools. Especially, as the recent trend in technology made it possible to manipulate a further miniaturized structures, required simulations for emerging material be...