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17 articles for “DFT”
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Research ArticleOpen accessIn the keywordsThe Investigation of 1H NMR Spectra of 2,3-Dihydro-4-Pyridinones Derived from BisdemethoxycurcuminWisam A. Radhi, Bahjat A. SaeedProblem statement: The studied dihydropyridones were synthesized via microwave assisted reaction of bisdemethoxycurcumin and amines or amine acetates which is new approach in the synthesis of this important class of compounds and the deep study of their NMR spectra seems reasonable. Approach: 1H NMR spectra of dihydropyridones derived from curcumin were discussed and their structures were elucidated accordingly. Results: The … …American Journal of Applied Sciences, Vol. 7, Issue 8 · 31 Aug 2010 · 7,186 accessesView PDFCite
Research ArticleOpen accessIn the abstractComputer Aid Screening for Potential Antimalarial Choroquinone Compounds as Covid 19 Utilizing Computational Calculations and Molecular Docking StudyAsmaa Aboelnaga, Asmaa M. Fahim, Taghreed H. EL-SayedClick reaction of 4,7-dichloroquinoline (1) with thiosemicarbazide (2) to afford the corresponding 2-(7-chloroquinolin-4-yl)thiosemicarbazide (3) utilized ultrasonic irradiation which can cyclized easily with ethylacetoacetate to give the 3-(7-chloroquinolin-4-ylamino)-tetrahydro-6-methyl-2-thioxopyrimidin-4(1H)-one (4) via nucleophilic substitution reaction. The synthesized compounds was examined in vitro antimalarial activity with IC50 = 11.92, 25.37 μg/mL against chloroquinone drug. Furthermore, the theoretical investigation of most active compounds CQT and … …OnLine Journal of Biological Sciences, Vol. 20, Issue 4 · 30 Nov 2020 · 6,568 accessesView PDFCite
Research ArticleOpen accessIn the abstractInverse Discrete Fourier Transform-Discrete Fourier Transform Techniques for Generating and Receiving Spectrally Efficient Frequency Division Multiplexing SignalsSahmed IdarwazehProblem statement: Spectrally Efficient Frequency Division Multiplexing (SEFDM) system promises bandwidth savings by multiplexing overlapped non-orthogonal sub-carriers. However, the loss of orthogonality results in increasing the complexity of generation and detection of the signal. In this work, we propose simple framework for the generation of the SEFDM signal based on the Inverse Discrete Fourier Transform (IDFT). Approach: This study further … …American Journal of Engineering and Applied Sciences, Vol. 4, Issue 4 · 31 Jul 2012 · 8,310 accessesView PDFCite
Research ArticleOpen accessIn the abstractAn Initio Theoretical Study for the Electronic Spectra of β-ThioxoketonesRita S. Elias, Bahjat A. Saeed, Dhiyaa K. MuslemProblem statement: β-thioxoketones exist as equilibrium mixtures of the tautomeric enol and enethiol forms which interconvert very rapidly by intramolecular chelate proton transfer. Accordingly their electronic spectra in the u.v.-visible region exhibit absorption bands arising from transitions within the electronic systems involved in these tautomers. Approach: The structures of several β-thioxoketones were geometrically optimized using B3LYP/cc-pVTZ, B3LYP/6-311++G (2d,p), PM2/6-311++G(2d,p) and … …American Journal of Applied Sciences, Vol. 9, Issue 1 · 24 Nov 2011 · 7,854 accessesView PDFCite
Research ArticleOpen accessIn the abstractTheoretically Predicted Descriptors Based Quantitative Structure Activity Relationship Study of the Activity of Acridines Against B-16 MelanomaBahjat A. Saeed, Rita S. Elias, Sadiq M-H. Ismael, Kawkab A. HussainProblem statement: The probability of success and reducing time and coast in drug discovery process could be increased on the basis of QSAR techniques. The study involves the QSAR investigation of 20 bioactive acridines that have activity against Approach: Molecular descriptors, total energy, van der Waals volume, molecular volume, HOMO energy, HOMO-LUMO energy gap, polarizability, refractivity, bond angle of C8-N9-C2 … …American Journal of Applied Sciences, Vol. 8, Issue 8 · 18 Jul 2011 · 7,689 accessesView PDFCite
Research ArticleOpen accessIn the abstractA Software Agent for Speech Abiding SystemsR. Manoharan, K. Vivekanandan, V. SundaramProblem statement: In order to bring speech into the mainstream of business process an efficient digital signal processor is necessary. The Fast Fourier Transform (FFT) and the butter fly structure symmetry will enable the harwaring easier. With the DSP and software proposed, togetherly established by means of a system, named here as “Speech Abiding System (SAS)”, a software agent, which … …Journal of Computer Science, Vol. 5, Issue 2 · 28 Feb 2009 · 7,744 accessesView PDFCite
Research ArticleOpen accessIn the abstractComparison of Speech Features on the Speech Recognition TaskIosif Mporas, Todor Ganchev, Mihalis Siafarikas, Nikos FakotakisIn the present work we overview some recently proposed discrete Fourier transform (DFT)- and discrete wavelet packet transform (DWPT)-based speech parameterization methods and evaluate their performance on the speech recognition task. Specifically, in order to assess the practical value of these less studied speech parameterization methods, we evaluate them in a common experimental setup and compare their performance against traditional … …Journal of Computer Science, Vol. 3, Issue 8 · 31 Dec 2007 · 7,117 accessesView PDFCite