نتایج جستجو برای: مطالعه dft
تعداد نتایج: 297438 فیلتر نتایج به سال:
A gold(I) complex with a triphenylphosphine and a monodentate N,N-dimethyldithiocarbamate ligand was synthesized and characterized by Raman spectroscopy and single crystal X-ray diffraction. DFT calculations (Gaussian 09, PBE1PBE/Lanl2dz) were undertaken for a single complex in the gas-phase. The DFT-optimized structure is in good agreement with the crystal structure and the DFT-calculated Rama...
In this study, a dynamic field theory (DFT) based cognitive model of a pilot performing pitch attitude control of a 3 degree of freedom aircraft model is presented. The cognitive model is validated by comparing the pilot model’s pitch attitude hold performance with real flight test results of a human pilot on a real aircraft. A high degree of similarity was observed between the behaviour of the...
Recently DFT based discrete multitone modulation (DMT) systems have been widely applied to various applications. In this paper we study a broader class of DMT systems using more general unitary matrices instead of DFT matrices. For this class we will show how to design the optimal DMT systems over fading channels with colored noise. Examples will be given to show the improvement over the tradit...
We apply the theory of Weyl-Heisenberg frames (WHFs) to oversampled FIR and IIR DFT filter banks (FBs). We show that the polyphase matrices provide a matrix representation of the frame operator, and we find conditions on a DFT FB to provide a WHF expansion. We also show that paraunitary and biorthogonal DFT FBs correspond to tight and exact WHFs, respectively, and that the frame bounds can be o...
BACKGROUND Biphasic waveforms reduce defibrillation threshold (DFT) in a wide variety of models. Although there are several human studies of long-duration, high-tilt biphasic waveform defibrillation, the specific biphasic waveform shape required to achieve optimal DFT reduction is unknown. METHODS AND RESULTS This study tested the effect of single capacitor biphasic waveform tilt modification...
Serious (up to 87 kJ mol(-1)) systematic DFT errors in a series of isodesmic reactions are found to be due to the DFT exchange component, and can be largely corrected by substitution of the DFT exchange energy with the Fock exchange energy.
مقدمه : پریودنتیت و پوسیدگی دندانی می توانند در یک سو وبه صورت دو عامل همکار , معکوس یکدیگر و یا کاملاً مستقل از هم عمل کنند. هدف از این مطالعه بدست آوردن رابطۀ بین این دو بیماری است و میزان شیوع پوسیدگی در بیماران پریودنتالی را مورد بررسی و مقایسه قرار میدهد. مواد و روش ها: این مطالعه به روش cross sectional بر روی 180 نمونه در دو گروه پریودنتال و کنترل در طی سالهای 92-91 در دانشکده دندانپزشکی ب...
One obstacle in orbital-free density functional theory (OF-DFT) is the lack of accurate and transferable local pseudopotentials (LPSs). In this work, we build high quality LPSs by inverting Kohn-Sham (KS) equations on bulk valence electron densities to obtain an atom-centered local pseudopotential. With this approach, we build LPSs for Mg, Al, and Si, and then test them in KS DFT calculations o...
OBJECTIVES The purpose of this study was to prospectively investigate the influence of ventricular fibrillation (VF) durations of 5, 10 and 20 s on the defibrillation threshold (DFT) during implantable cardioverter-defibrillator (ICD) implantation. BACKGROUND Although the DFT using monophasic waveforms has been shown to increase with VF duration in humans, the effect of VF duration on defibri...
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