نتایج جستجو برای: dft study

تعداد نتایج: 3981622  

In this study, we theoretically investigated Methyl hydrazinecarbodithioate by quantum chemical calculations for geometry optimization, vibration frequencies, and electronic structure parameters. The geometry optimization by DFT, ab initio MP2 method and the frequency calculation by DFT method was performed at the highest available Pople style 6-311G++(3df,3pd) basis set level. The semi-emp...

2005
Igor Djurović Vladimir V. Lukin Alexey A. Roenko

A task of filtering (denoising) of high-pass signals corrupted by heavy tail (α-stable) noise is considered. For this purpose, several techniques based on the robust DFT forms have been proposed recently. In this paper we study various approaches for design of the robust DFT and compare their performance for frequency-modulated (FM) signals. In particular, we consider the DFT estimates based on...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2003
Kang Kim Toyonori Munakata

The glass transition of a hard sphere system is investigated within the framework of the density functional theory (DFT). Molecular dynamics (MD) simulations are performed to study the dynamical behavior of the system on the one hand and to provide the data to produce the density field for the DFT on the other hand. Energy landscape analysis based on the DFT shows that there appears a metastabl...

Abstract: Electrical sensitivity of a beryllium oxide nanotube (BeONT) was examined toward (C5H5N) molecule by using density functional theory (DFT) calculations at the B3LYP/6-31(d) level, and it was found that the adsorption energy (Ead) of pyridine on the pristine nanotubes is   a bout -73.29kcal/mol. But when nanotubes has been doped with S and P atomes , t...

Journal: :Cardiology journal 2007
Burr Hall Vinodh Jeevanantham Ethan Levine James Daubert Scott McNitt Freburr Hall Fred Morady And Frank Pelosiburr Hall Fred Morady And Frank Pelosid Morady Frank Pelosi

BACKGROUND Inability to perform defibrillation threshold (DFT) testing during implantable cardioverter defibrillator (ICD) implantation due to co-morbidities may influence long-term survival. METHODS Retrospective review at The University of Michigan (1999-2004) identified 55 patients undergoing ICD implantation without DFT testing ("No-DFT group"). A randomly selected sample of patients (n =...

Journal: :Turkish computational and theoretical chemistry 2022

This paper has reported some theoretical results for the geometry optimization in ground state (S0) and first excited (S1), frontier molecular orbitals, global chemical reactivity descriptor, states, absorption emission spectra gas phase aqueous solution of protonated Adenosine diphosphate molecule. Also, intramolecular proton transfer process was between O37-H38∙∙∙N13 bonds. Then, obtained hav...

2012
Beata Ujvari Anne-Maree Pearse Robyn Taylor Stephen Pyecroft Cassandra Flanagan Sara Gombert Anthony T. Papenfuss Thomas Madsen Katherine Belov

BACKGROUND Devil Facial Tumour Disease (DFTD) is a unique clonal cancer that threatens the world's largest carnivorous marsupial, the Tasmanian devil (Sarcophilus harrisii) with extinction. This transmissible cancer is passed between individual devils by cell implantation during social interactions. The tumour arose in a Schwann cell of a single devil over 15 years ago and since then has expand...

1997
Soo-Chang Pei Chien-Cheng Tseng

This paper is concerned with the definition of the discrete fractional Fourier transform (DFRFT). First, an eigendecomposition of the discrete Fourier transform (DFT) matrix is derived by sampling the Hermite Gauss functions which are eigenfunctions of the continuous Fourier transform and by performing a novel error removal procedure. Then, the result of the eigendecomposition of the DFT matrix...

2008
JOEL A. TROPP

The purpose of this work is to survey what is known about the linear independence of spikes and sines. The paper provides new results for the case where the locations of the spikes and the frequencies of the sines are chosen at random. This problem is equivalent to studying the spectral norm of a random submatrix drawn from the discrete Fourier transform matrix. The proof depends on an extrapol...

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