查看更多>>摘要：H - bond interactions between acetonitrile(AN)/dimethyl sulfoxide(DMSO) and acetylacetone (AcAc) have been investigated using time domain reflectometry studies. The relaxation time values confirm that 1:1 complex has been formed between AN/DMSO and AcAc, and both the keto and enol forms of AcAc exist as monomers. Antiparallel and parallel alignment of AN/DMSO - AcAc H - bonded dipoles in AN/DMSO and AcAc rich solutions, respectively, have been identified. The g(f) values indicate that non-classical H - bond interactions are operative in AN/DMSO - AcAc solutions. The epsilon(E) vs phi(2) suffers quantitatively a large change from the epsilon(E) vs X-2 plot but, they qualitatively agree each other.
Goncalves, Juliana A.dos Santos, Osmar F. P.Batista, Ronaldo J. C.Azevedo, Sergio...
9页
查看更多>>摘要：We employed first-principles calculations to investigate the fluorination of silicon carbide nanosheets. We found that the Si atoms are the energetically favorable adsorption sites for F atoms in silicon carbide nanosheets in all studied cases. The strain caused by the fourfold coordinated Si atoms in the flat SiC nanosheet determines the relative position of the adsorbed F atoms: occupying nearest-neighbor Si sites if they bound sheet's opposing sides or away from each other if they are on the same side of the sheet. The fluorinated nanosheets' electronic and magnetic properties are weakly dependent on which side of the sheet the F atoms bind; however, they are strongly dependent on the relative distance between them. For F atoms adsorbed on nearest-neighbor Si sites, the system is a small gap p-type semiconductor with 1 mu(B) per adsorbed atom. On the other hand, if F atoms do not occupy nearest-neighbor Si sites, the system is a metal with 1/2 mu(B) per adsorbed atom. The adsorption of F atoms strongly affects the optical properties of SiC sheets inducing optical anisotropy regarding the direction of the incidence of light.
da Silva, Tales J.Caldas, Marilia J.Galvao, Douglas S.Fonseca, Alexandre F....
5页
查看更多>>摘要：A new auxetic (negative Poisson's ratio values) structure based on a gamma-graphyne structure, here named A gamma G structure, is proposed. The A gamma G structural/mechanical and electronic properties, as well as its thermal stability, were investigated using classical reactive and quantum molecular dynamics simulations. A gamma G is shown to have a bandgap larger than 1.6 eV and be thermally stable at a large range of temperatures. The classical and quantum results validate that the A gamma G is auxetic, both when isolated (vacuum) and when deposited on a copper substrate. We believe that this is the densest auxetic structure belonging to the graphyne-like families.
查看更多>>摘要：Time and wavelength-resolved laser-induced incandescence (LII) study is performed in a titania nanoparticlegenerating flame under different laser fluences. Measurements of the flame light emission are performed during the laser pulse and at short delay times. The results cannot be explained within the traditional description of heat exchange mechanisms between particles and the environment. The paper suggests to distinguish electron and phonon temperatures in the nanoparticles in order to reconcile observations. The fundamental phenomenon responsible for a possibility of that temperature difference and its implication to pyrometry measurements in flames is discussed and justified in the paper.
Bogomolov, Alexandr S.Rogoveshko, Vladislav M.Baklanov, Alexey, V
6页
查看更多>>摘要：The satellite lines belonging to the clusters of tetracene Tc with He are revealed in REMPI spectra of Tc seeded in the supersonic expansion of He. These well-resolved peaks are shifted to the red by 35.7(9) cm(-1) relative to the lines of bare Tc. The data by Even et al. (J. Chem. Phys.115, 2069 (2001)) on the shift of absorption lines for clusters Tc-(He) N allow us to assign this peak to Tc-(He)8 cluster. This result confirms one of the earlier suggested structures of the first layer of He atoms surrounding tetracene in the He nanodroplet.
查看更多>>摘要：The harmonic emissions from different periodic potentials have been investigated by solving the time-dependent Schro center dot dinger equation. The results show that by superposing the static electric field to the fundamental laser field and changing the shape of the bichromatic potential, the harmonic efficiency of the second plateau can be enhanced 5-6 orders of magnitude. Moreover, the related quantum paths are efficiently manipulated, and the harmonic emission is dominated by single short quantum path. With energy band, time-dependent population imaging and time-frequency analysis, the underlying electron dynamics is provided.
查看更多>>摘要：Organic-inorganic complex photocatalyst is constructed via the hydrothermal method. PDINH monolayers self assemble into lamellar organic supramolecular carriers under 7C-7C stacking. Under acidic conditions, -OH was introduced into Bi2WO6 crystal, and the hydrothermal reaction system made it interact better with the -C=& nbsp;O bond on PDINH, forming hydrogen-like bond -CO...H, which aggregated on the exterior of PDINH by van der Waals force. The matched energy band situations of the two nanomaterials and the close integrated interfaces promoted the constitution of a nano lamellar structure, which enhanced the charge carrier separation efficiency. The catalyst with a molar ratio of 0.5:0.4 (PDINH: Bi2WO6) was synthesized at 140? for 24 h and had excellent photocatalytic activity. The photocatalytic performance of P/T/B under visible light was evaluated by using 6 ppm aqueous phenol solution as a degradation target. The degradation rate of phenol in aqueous solution was 98% in 350 min. The photocatalytic performance for the degradation of phenol by PDINH/Bi2WO6 was increased twice when compared with PDINH, and four times higher than that of pure Bi2WO6. Furthermore, the stability of Bi2WO6 was reinforced considering the presence of PDINH supramolecular as a carrier, which further improved the recycling and utilization of photocatalyst.
查看更多>>摘要：The influence of the experimental parameters and their interactions on saturation magnetization (M-s) of NiFe2O4 thin films have been determined by the experimental design methodology. The saturation magnetization (M-s) is very influenced by the deposition and annealing temperature, which are proved by Rechtschaffner design. The optimal condition of the NiFe2O4 thin film has been predict by Doehlert matrix. The structure and the phase identification of the prepared NiFe2O4 thin film under optimal condition were determining by XRD, FTIR and Raman. The SEM analysis has revealed the flower-like structure of the NiFe2O4 thin film. The ferrimagnetic behavior of the NiFe2O4 thin film has been determining by VSM measurement. The saturation magnetization (M-s = 0.49 T) is in agree with M-s (0.48 T) predict by Rechtschaffner design. The double-layer capacitance (EDLC) of NiFe2O4 has been investigating by cyclovoltammetry, which show a semi-rectangular shape in the negative and positive potential. The electrochemical impedance spectroscopy has confirmed the resistance behavior of the NiFe2O4 electrode.& nbsp;& nbsp;
查看更多>>摘要：rGO-BaSnO3 nanocomposite was prepared by hydrothermal route. The physicochemical properties were analyzed by spectroscopic analysis. From the results, the rod-like crumbled particles were well dispersed on rGO sheets. The optical bandgap was found to be 2.72 eV for BSG-10 which is comparatively lower than BS. The implementation of rGO makes an interfacial contact with BS facilitates e(- )transfer from BS to rGO, effectively suppresses the e (-)/h(+) pair recombination rate. The BSG-10 nanocomposite exhibits 94 % degradation efficiency under 180 min of visible light irradiation. The radical contributions involved in degradation process and the stability of the photocatalysts are also discussed.& nbsp;& nbsp;
查看更多>>摘要：We determined the structural, mechanical, electronic and magnetic properties of the Co2VGa by using full-potential linearized augmented plane-wave (FP-LAPW) method and Monte Carlo simulation. The structural stability studies were performed for nonmagnetic, ferromagnetic and antiferromagnetic states. The elastic parameters and their derivatives have been calculated. The investigated energy band structure shows that the Co2VGa is half metallic. The total magnetic moments, stiffness constant of spin wave and the Curie temperature are also calculated. The magnetocaloric effect of this material are studied using the results obtained by FP-LAPW. The transition temperature, magnetic entropy change and relative cooling power are calculated.
NSTL
Elsevier