DFT Research Papers - Academia.edu (original) (raw)

ABSTRACT On the basis of literature interpretation of 13C NMR and 1H NMR spectra of bis-quinolizidine alkaloids, the values of free enthalpy ΔG of conformational equilibria of those compounds were calculated. The results were analysed together with the X-ray and DFT data to discuss the effects of different substituents attached to the sparteine system in various positions as well as the effects of structural modifications on conformational equilibria. The measure of the effect was expressed by ΔΔG value, defined as the difference in ΔG of the compound under consideration and its parent compound without a given substituent.

- by and +1
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- DFT, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Molecular Structure
- by Aleksandar Peulic
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- DFT, THEORETICAL AND COMPUTATIONAL CHEMISTRY
- by Alejandro Granados
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- Chemistry, Inorganic Chemistry, Crystallography, Crystal structure
- by Jarun Lomratsiri
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- Thermodynamics, Adsorption, Zeolites, Computer Software
- by Beata Szefler
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- DFT, THEORETICAL AND COMPUTATIONAL CHEMISTRY, Molecular Structure
- by M Jake Pushie
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- Canadian, DFT, CHEMICAL SCIENCES
- by Marwan Jaber
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- Signal Processing, Digital Signal Processing, VLSI, Parallel Processing
- by Adel El-Azhary
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- Analytical Chemistry, Quantum Mechanics, DFT, Density Functional Theory

Abstract: 2-Ethoxy-6-[(E)-[(2-hydroxyphenyl)imino]methyl]phenol derivative Schiff bases (4-chloro-2-((3-ethoxy-2-hydroxybenzylidene)amino)phenol; 5S1 and 2-((3-ethoxy-2-hydroxybenzylidene)amino)-4-methylphenol; 5S2 have been synthesized and characterized with 1H-NMR, 13C-NMR, IR and elemental analysis in this study. The stable conformers and possible tautomer forms of Schiff base derivatives have been determined in theoretical calculations. All the calculations considering for the energetically stable conformers were performed with Gaussian09 program by using B3LYP/6-311g(2d,p) level of theory. The Gibbs Free energies, stable tautomer forms, H-bond, Mulliken charges, dipole moments, solvent accessibility surface areas (SAS), molecular electrostatic potential values, HOMO, LUMO and band gap energies (EGAP) were also calculated. The consistency between the theoretical and experimental 1H-NMR, 13C-NMR and IR spectra has also been investigated.

- by Ülkü Dilek Uysal
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- SAS, DFT, MEP, Schiff Base
- by Arthur Edwards
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- Geochemistry, DFT, Activation Energy, Interdisciplinary Engineering
- by Alia Ungurean
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- Adsorption, Raman, DFT, THEORETICAL AND COMPUTATIONAL CHEMISTRY
- by Evelina Veltcheva
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- Structure, Neutron Diffraction, Ir, DFT
- by muhammad faheem
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- Biomass, DFT

An optimized effective potential (OEP) approach based on density functional theory for individual excited states and a simple to implement method which takes the orthogonality constraints into account (TOCIA) for the Kohn–Sham determinants is developed with the aim of constructing the orbital-dependent correlation energy corrections. It is shown that the TOCIA methodology makes it possible to apply both the OEP experience and the perturbative second-order correction for the ground state to the excited state problem with the same computational effort. A performance of the proposed method is demonstrated by calculations of excitation energies for the Li atom and HeH and LiHe molecules at the different levels of approximation. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007

- by Nikitas Gidopoulos
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- Quantum Chemistry, DFT, Second Order, THEORETICAL AND COMPUTATIONAL CHEMISTRY
- by Sethu Gunasekaran
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- Condensed Matter Physics, Thermodynamics, Chemistry, Analytical Chemistry
- by Michel Rajzmann
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- Organic Chemistry, DFT calculation, DFT, HF
- by Okan Ersoy
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- DFT, Matrix factorization, discrete Yang-Fourier transforms, Ducts
- by Jose Manrique
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- DFT, Estimation, FFT, Harmonics
- by Om Gandhi
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- Frequency-domain analysis, DFT, Synthetic Aperture Radar, FFT
- by Amit Pathak
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- Engineering, Chemical Physics, DFT, Physical sciences
- by Matthias Niemitz
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- Organic Chemistry, NMR Spectroscopy, Carbon Isotopes, DFT
- by GOWDHAM V S
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- Image Processing, DFT, DWT, DCT

- Radix-2 FFT algorithm is the simplest and most common form of the Cooley-Tukey algorithm. This considers radix-2 FFT processors and realization of butterfly operations. The properties, e.g., area and power consumption, of the FFT processor depend mainly on implementation of butterfly operations. These algorithms have been developed using verilog hardware descriptive language. Butterfly unit method reduces the number of multiplications and additions compared to formula method.

- by GRD JOURNALS
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- DFT, FFT, Decimation, cooley tukey
- by Angie Vanessa Jaramillo Castrillon
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- DFT, Pattern, Minutiae

This review aims to briefly outline the Hubbard-U scheme and to investigate the effect of its inclusion in standard Density Functional Theory on electronic, structural, and optical properties of ZnO wurtzite structure. To remedy the miscalculation of optimized lattice parameters determined by Local Density Approximation and Generalized Gradient Approximation approximations to experimental values, the effect of the implementation of Hubbard-U correction for only d state or for both d and p states was investigated for theoretical data collected from previous works. Further effort was devoted to studying the incorporation of U d,Zn and U p,O to reproduce correct band gap, to exploring various regions composed of valence and conduction bands and their origin, and to revealing the nature of chemical bonding. This review also provides graphical and tabulated values extracted from earlier works on optical properties of ZnO wurtzite structure. It summarizes the effect of U d,Zn and U p,O in several exchange-correlation functionals on the intensity and location of major peaks composed real and imaginary part of dielectric function as well as on the shift of main absorption peak and optical absorption edge. A comparison was made, wherever possible, between theoretical and experimental results.

- by Ahmad Azmin Mohamad
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- Electronics, DFT calculation, DFT, ZnO (Zinc Oxide)
- by Pradip Debnath
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- Organic Chemistry, Ph, DFT, Ammonium Nitrate

An orthonormal transformation in N-dimensional space can be obtained by choosing a set of N mutually orthogonal vectors and then normalizing their lengths to make them unit vectors. Alternatively, we can start from N orthogonal continuous functions, unifromly sample each of them appropriately ensuring that the N-samples of each of them treated as vectors are still orthogonal to each other and then normalizing those vectors to form the basis. Orthogonality of sinusoids with rational frequency ratio: With continuous sinusoidal functions, the area under the curve obtained by the product of two sinusoids of frequency equal to different integer multiples of the same fundamental frequency is zero over one period of the fundamental frequency.

- by Ali H Reshak
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- Materials Engineering, Condensed Matter Physics, DFT

In this paper, the implementation of the discrete sine transform (DST) and its inverse (IDST) are developed. General length structure of the DST and IDST, which can be implemented by using the recursive structures, has been proposed. Necessary formulas required for the recursive structures have been derived using mathematical manipulations. Copyright © 2007 John Wiley & Sons, Ltd.

- by Priyanka Jain
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- DFT, DCT, Circuit, Dst
- by Sergei Dudarev
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- Engineering, Materials, Clusters, Magnetism

Resumen. En el presente reporte se explica el proceso de implementación de un algoritmo que obtiene la transformada discreta de Fourier de una secuencia finita de muestras. Se utiliza el lenguaje de programación C para implementar el algoritmo en la herramienta de desarrollo Code Composer Studio 6.0. El algoritmo se descarga en una tarjeta de la serie TIVA C de Texas Instruments, la cual realizará el muestreo de una señal analógica, el procesamiento de esas muestras a través del algoritmo y enviará sus resultados a una computadora portátil por medio de la comunicación serial. Por último, mediante una aplicación en Java se procesan los datos obtenidos con la tarjeta y se grafican. Palabras clave: algoritmo, programación, señal analógica, transformada discreta de Fourier.

- by Zenón Martinez Cruz
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- DFT
- by Grigory Shamov
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- Relativistic cosmology, Modeling, Solvation, DFT
- by Nino Russo
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- Food Chemistry, Multidisciplinary, IP, Electron Transfer
- by Caio Firme
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- Aromaticity, DFT, Qtaim

An implementation of IEEE 1149.1 TAP controller is presented in this paper. JTAG is an established technology and industry standard for on-chip boundary scan testing of SoCs. JTAG TAP controllers are becoming a delivery and control mechanism for Design For Test. The objective of this work is to design and implement a TAP controller IP core compatible with IEEE 1149.1-2013 revision of the standard. The test logic architecture also includes the Test Mode Persistence controller and its associated logic. This work is expected to serve as a ready to use module that can be directly inserted in to a new digital IC designs with little modifications.

- by Nicholas C Bristowe
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- Multiferroics, Magnetism, Mathematical Sciences, DFT

In this study, the special quasi-random structure (SQS) approach has been
considered for structural, electronic and optical properties of rock-salt (RS) and zinc-blende
(ZB) phases of ZnO 1− x Te x (x= 0, 0.25, 0.5, 0.75 and 1) using density functional theory.
The Wu–Cohen generalized gradient approximation (GGA) has been employed for
optimizing the lattice parameters (a 0) and bulk moduli (B 0) in both phases which show
reasonable agreement with numerous theoretical and experimental results. To compute

- by Giovanni Maestri
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- Catalysis, DFT, Palladium
- by Claire McMullin and +1
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- Thermodynamics, Inorganic Chemistry, Quantum Theory, Dispersion
- by Jingjing Zheng
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- DFT, Barrier height

In this paper we present two designs of CMOS blocks suitable for integration with RF frontend blocks for test purposes. Those are a programmable RF test attenuator and a reconfigurable low noise amplifier (LNA), optimized with respect to their function and location in the circuit. We discuss their performances in terms of the test- and normal operation mode. The presented application model aims at a transceiver under loopback test with enhanced controllability and detectability. The circuits are designed for 0.35μm CMOS process. Simulation results of the receiver frontend operating in 2.4 GHz band are presented showing tradeoffs between the performance and test functionality.

- by Rashad Ramzan
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- Technology, DFT, Process Simulation, Low noise amplifier
- by Sharif F Zaman
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- Chemical Engineering, Kinetics, Catalysts, DFT
- by Oscar Ventura
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- Reaction Mechanisms, Density-functional theory, Molecular, DFT
- by Abhishek kumar Mishra
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- Computer Science, Physics, Physical Chemistry, DFT
- by Jerry Chan
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- Engineering, Materials Engineering, Chemical Engineering, Condensed Matter Physics
- by Gary Brudvig
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- Inorganic Chemistry, Artificial Photosynthesis, GC-MS, DFT
- by John Parkinson
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- Chemical Engineering, DFT, Nitrogen, Methylene Blue

In this paper, a novel two-dimensional Discrete Fourier Transform based information embedding has been proposed for color image authentication (2D-DFTSDECIA). Initially, each 2 × 2 sub-image block of the carrier image is pre-adjusted, if necessary and then transformed by the application of two dimensional Discrete Fourier Transforms (2D-DFT) where the transformation technique has been applied in row major order. In the proposed 2D-DFTSDECIA scheme, two bits from the authenticating message/image can be embedded in second, third and fourth frequency components of every 2 × 2 green sub-image matrix.Similarly, three bits from the authenticating message/image are embedded in second, third and fourth frequency components of every 2 × 2 red and blue sub-image matrices because, the human eye is less sensitive in blue and red channels as compared to the green channel. The first frequency component of green channel hides one bit at the pre-LSB position whereas two bits are embedded in first frequency component of red and blue channels starting from the pre-LSB. After embedding authenticating image/message bits, a frequency adjustment method is applied to get frequency component values closer to the actual frequency component value without hampering the embedded bits. Inverse 2D-DFT (2D-IDFT) is applied on each 2 x 2 image block after embedding authenticating message/image bits to generate embedded image. During the inverse transform phase, if any fractional value occurs in spatial domain, then the least significant bit of the first frequency component of that sub-matrix is flipped and 2D-IDFT is applied again. Experimental results conform that the proposed algorithm performs better than DPTHDI [7] and previously proposed DFTIECIA [8] schemes in terms of qualities and payload capacities.

- by Signal & Image Processing : An International Journal (SIPIJ) - WJCI Indexed and +1
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- DFT, 2D-DFTSDECIA, DFTIECIA, DPTHDI

The embedded core testing methodology at Advanced Micro Devices Inc. Involves adopting a disciplined system for developing new products with a focus on time to market and engineering productivity. A key factor is to achieve high and verifiable fault coverage for designs by closely adhering to guidelines and by increased test automation. This paper addresses the design for test (DFT) aspects of the methodology, production testing of embedded CPU cores, and provides some data on completed designs

- by Asif Khan
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- Embedded Systems, DFT, System on a Chip, Design for Testability