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51.
Mahmoud Mirzaei Kun Harismah Elham Jafari Oğuz Gülseren Ali Shokuhi Rad 《The European Physical Journal B - Condensed Matter and Complex Systems》2018,91(1):14
Density functional theory (DFT) calculations were performed to investigate stabilities and properties for uracil (U)-functionalized carbon nanotubes (CNTs). To this aim, the optimized molecular properties were evaluated for (n, 0) models of CNTs (n = 3–16) in the original and U-functionalized forms. The results indicated that the dipole moments and energy gaps were independent of tubular diameters whereas the binding energies showed that the U-functionalization could be better achieved for n = 8–11 curvatures of (n, 0) CNTs. Further studies based on the evaluated atomic-scale properties, including quadrupole coupling constants (C Q ), indicated that the electronic properties of atoms could detect the effects of diameters variations of (n, 0) CNTs, in which the effects were very much significant for the atoms around the U-functionalization regions. Finally, the achieved results of singular U, original CNTs, and CNT-U hybrids were compared to each other to demonstrate the stabilities and properties for the U-functionalized (n, 0) CNTs. 相似文献
52.
New composite superionic systems, [CdHgI4?:?0.2AgI]?:?0.xKI and [CdHgI4?:?0.2AgI]?:?0.xK2SO4 (x?=?0.2, 0.4, 0.6?mol. wt%), were prepared, using [CdHgI4?:?0.2AgI] mixed composite system as the host. Electrical conductivity was measured to study the transition behavior at frequencies of 100?Hz, 120?Hz, 1?kHz, and 10?kHz in the temperature range from 150°C to 250°C using a GENRAD 1659 RLC Digibridge. A sharp increase in conductivity was observed during β?→?α phase transition. Upon increasing the dopant-to-host ratio, the conductivity of the superionic systems exhibited Arrhenius (thermally activated)-type behavior. Differential thermal analysis, differential scanning calorimetry, thermogravimetric analysis, and X-ray powder diffraction were performed to confirm the doping effect and transition in the host. The phase transition temperature increased with an increase in the dopant concentration. Activation energies in eV for pre- and post-transition phase behavior are reported. 相似文献
53.
54.
We examine the nonlinear dynamical behavior of a spinor Bose-Einstein condensate in a double-well potential. Considering a condensate with large number of atoms, such that it can be described using the mean field theory, we separate the spinor dynamics from the spatial dynamics under the single-mode approximation. We limit ourselves to certain initial conditions under which the spatial mode is frozen so that we can focus on the spinor dynamics only. Identifying collective spin variables of our system, we derive the corresponding nonlinear equations of motion for them. Employing standard stability analysis, we find and characterize fixed points of the system. For a wide range of physical parameters such as tunneling strength and non-linear interactions, as well as for various initial preparations of the system, we identify qualitatively different dynamical regimes possible in the system. In particular, complete and incomplete oscillations of spin variables between quantum wells are found. We also show that by bringing some fixed points close to each other in the phase space of the system, it is possible to induce amplitude modulation to those otherwise regular tunneling oscillations. 相似文献
55.
Exposure of powder forms of DL-2-aminoadipic acid and ammonium acetate to gamma radiation results in the formation of free radicals detected by the electron paramagnetic resonance spectroscopy at room temperature. In these compounds, the observed paramagnetic species were attributed to the HOOCCH2CH2CH2CHCOOH and CH2COONH4 radicals, respectively. The g values and the hyperfine coupling constants of the unpaired electron with the environmental protons were determined for these two radicals. In work, the observed paramagnetic species were found to be stable at room temperature for more than two months. Also, these compounds were characterised by FT-IR and UV–VIS. Their thermal stabilities were determined by TGA and DTA measurements. Thermal analyses were shown to be unstable of the HOOCCH2CH2CH2CH(NH2)COOH and CH3COONH4 against thermo-oxidative decomposition. 相似文献
56.
The electron paramagnetic resonance spectra of γ-irradiated powders of α-(methylamino)isobutyric acid – CH3NHC(CH3)2COOH, α -aminoisobutyric acid methyl ester hydrochloride – NH2(CH3)2CCOOCH3 HCl, and diethylmalonic acid – (CH3CH2)2C(COOH)2 have been investigated at room temperature. It has been found that γ -irradiation produces the (CH3)2C˙COOH radical in the first, the (CH3)2C˙COOCH3 radical in the second and the (CH3CH2)2C˙COOH radical in the third compound. The spectra were computer-simulated. The g values and the hyperfine coupling constants of the unpaired electron with the environmental methyl, methylene protons and OH proton were determined. The results were found to be in good agreement with the existing literature data and theoretical predictions. 相似文献
57.
The voltammeric behavior of bupirimate fungicide has been studied by square wave stripping voltammetry (SWSV). The insoluble R–HgS salt (where R is the bupirimate frame excluding sulfur) formed on the static hanging mercury drop electrode (SHMDE) was electrochemically reduced by giving a fairly well defined cathodic peak within the pH range of 1.0 to 8.0. The peak potentials (E p) were shifted toward more negative values with increasing pH, and a maximum peak response appeared at ?1320 mV (vs. Ag/AgCl) at a pH 6.0. The calibration plot was a straight line in the range of 0.013 to 9.43 mg L?1. The detection limit at pH 6.0 was measured as 4.0 μg L?1 under the conditions of E acc?=??700 mV and t acc?=?10 s. The validity of the recommended method was assessed from the recoveries of spiked tap water, natural peach juice, and commercial peach juice. 相似文献
58.
59.
In this study, Tungsten Oxide (WO3) thin films were prepared by Chemical Spray Pyrolysis (CSP) and Spin Coating (SC) techniques and it was investigated effects of technique and parameter on the films. WO3 thin films were deposited on ITO (Indium Tin Oxide) coated glasses. The structural, optical and electrochromic properties of the WO3 thin films were characterized by XRD, SEM, UV, and CV measurements. The sharpest (200) peak was observed in the XRD spectra and optical band gaps were calculated around 2.6~3.1 eV via UV-Vis spectra for all of the samples. Micro fibrous reticulated surface (filamentous like) morphology for the films deposited by CSP technique and smooth surface morphology with high optical transmittance for the film deposited by SC Technique were obtained from SEM images. In addition to these results, it was revealed that all the samples exhibit good electrochromic performance. 相似文献
60.
Shafqat Hussain Hakan F. Öztop Khalid Mehmood Nidal Abu-Hamdeh 《Chinese Journal of Physics (Taipei)》2018,56(2):484-501
A computational analysis has been performed on mixed convection in a double sided lid-driven cavity in the presence of volumetric heat generation or absorption. Effects of inclined magnetic field are also studied. The governing parameters are solved via Galerkin weighted residual finite element method in space and the Crank–Nicolson in time. Governing parameters are nanoparticle volume fraction (0.0?≤???≤?0.04), Richardson number (0.01?≤?Ri?≤?10), internal heat generation or absorption parameter inclination angle of magnetic field (0°?≤?γ?≤?90°) and Hartmann number (0?≤?Ha?≤?100). It is observed that the highest heat transfer is obtained in case of the maximum value of heat absorption. As a further finding, heat transfer decreases with increasing of Hartmann number and increases with increasing of nanoparticle volume fraction. 相似文献