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991.
The present investigation deals with the mechanical, thermal, and morphological properties of binary nylon 66/maleic anhydride grafted ethylene propylene rubber (EPR‐g‐MA) blends at different dispersed phase (EPR‐g‐MA) concentrations. The effects of EPR‐g‐MA concentration and dispersed particle size on the mechanical properties of the blends were studied. Analysis of the tensile data in terms of various theoretical models revealed the variation of stress concentration effect with blend composition and the improvement of interfacial adhesion between dispersed rubber phase and nylon 66 matrix. The thermal degradation of the blends was analyzed by nonisothermal thermogravimetric analysis (TGA). It was found that the activation energy (Ea) and overall reaction order of thermal degradation decreased with increasing EPR‐g‐MA content. The scanning electron microscopic (SEM) analysis showed a significant decrease in dispersed particle size with increasing EPR‐g‐MA content, which was explained on the basis of the level of chemical interaction (in situ compatibilization) between nylon 66 and EPR‐g‐MA. The surface morphology of the nylon 66/EPR‐g‐MA blends was illustrated by the roughness of atomic force microscopy (AFM) images. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
992.
Kritika Gour Gargi Kundu Soumya Ranjan Dash Dr. Kumar Vanka Dr. Srinu Tothadi Dr. Sakya S. Sen 《欧洲无机化学杂志》2023,26(21):e202300167
This paper describes the rare use of a 6-membered saturated N-heterocyclic carbene (NHC) known as 1,3-di(2,6-diisopropylphenyl) tetrahydropyrimidine-2-ylidene (abbreviated as 6-SIDipp) as a ligand in zinc chemistry. We report on the investigation of the reactions between 6-SIDipp and ZnX2, which resulted in a range of new monomeric 6-SIDipp⋅ZnX2 complexes (X=Et ( 1 ), Cl ( 2 ), Br ( 3 ), and I ( 4 )). We also prepared a new NHC zinc complex where the two substituents of the zinc atom are different, 6-SIDipp⋅Zn(Et)Br ( 7 ) through the reaction of the proligand [6-SIDippH]Br with ZnEt2. We have observed that the reactions of complex 1 with sulfur and HBpin led to the removal of the ZnEt2 moiety, resulting in the formation of a C=S double bond and a B−H activation product, respectively. Lastly, the reaction of 1 with five-membered NHCs led to the exchange of carbene and the formation of either 5-IDipp⋅ZnEt2 ( 8 ) or 5-SIDipp⋅ZnEt2 ( 9 ). 相似文献
993.
Anisotropic charge transport properties of chrysene derivatives as organic semiconductor: A computational study 下载免费PDF全文
Rudranarayan Khatua Smruti Ranjan Sahoo Sagar Sharma R. Thangavel Sridhar Sahu 《Journal of Physical Organic Chemistry》2018,31(10)
We used density functional theory to calculate the angular resolution anisotropic charge mobility of the substituted chrysene molecules, viz, 4,10‐diphenoxychrysene (DPC), 4,10‐bis(phenylsulfanyl)chrysene (BPSC), and ethyl 8,9,12‐trimethoxychrysene‐6‐carboxylate (ETCC). The highest occupied molecular orbital–lowest unoccupied molecular orbital gap for DPC, BPSC, and ETCC was calculated to be 3.92, 3.83, and 3.81 eV, respectively, which inferred the compounds to be wide‐band‐gap semiconductors indicating that the compounds should have high stability in atmospheric conditions. The fact is also supported by electronic band‐structure calculation. In addition, higher electron affinity of studied compounds as compared with the bare chrysene molecule imparts enhancement of n‐type character in the compounds. The maximum hole ( ) and electron mobilities ( ) for DPC compound were found to be 0.739 cm2V?1s?1 and 0.319 cm2V?1s?1, respectively, at Φ = 0°. On the other hand, in the case of BPSC crystal, comparatively larger anisotropic electron mobility (0.709 cm2V?1s?1 at Φ = 0° and Φ = 179.90°) than the hole mobility (0.208 cm2V?1s?1 at Φ = 127.19° and Φ = 307.10°) was noted. Similarly, in ETCC, the parallel dimers were found to contribute maximum and of 0.052 and 0.102 cm2V?1s?1, respectively, at Φ = 0°. The substitution of ‐SPh in BPSC and ‐OCH3 and ‐CO2CH2CH3 in ETCC have relatively more impact on band reduction than ‐OPh in DPC, thus facilitating electron transport in BPSC and ETCC. 相似文献
994.
Rafael Julius Abdel-Baset M. A. Ibrahim Mohd Kamil Abd-Rahman P. K. Choudhury 《Optical Review》2018,25(5):563-570
Quantum dynamics of a four-channel nonlinear directional coupler, based on Kerr effect, was modeled numerically by a set of stochastic differential equations derived using quasiprobability distribution of positive-\(P\) representation. The modeling of the system is focused on the properties of quadrature evolution below the standard quantum limit, and its comparison with the conventional two-channel device. The results exhibit that a four-channel Kerr coupler provides an effective way to manipulate squeezing, especially in the mixed-mode basis, as compared with the conventional two-channel system—the theme that would make these to be prudent squeezed light source. 相似文献
995.
This article analyses the operation of an atomic force microscope whose cantilever, which is heated at its free end, is used to map topography and thermal features across a sample surface. The analysis takes into account the thermal flow along the cantilever, between the cantilever and sample via air, and through the constriction formed at the tip-sample contact area. The thermal flow through the constriction is analysed in terms of Maxwell and Sharvin components as given by Wexler. Examples using silicon tips and samples with a rectangular grid consisting of (a) silicon and silicon oxide features and (b) silicon oxide steps of 100 nm height, show that long tips are more sensitive to the thermal features of the sample while short once are more sensitive to its topography. 相似文献
996.
We investigate the effect of metal permittivity on resonant transmission of metamaterials by terahertz time-domain spectroscopy. Our experimental results on double split-ring resonators made from different metals confirm the recent numerical simulations [Phys. Rev. E 65, 036622 (2002)] that metamaterials exhibit permittivity-dependent resonant properties. In the terahertz regime, the measured inductive-capacitive resonance is found to strengthen with a higher ratio of the real to the imaginary parts of metal permittivity, and this remains consistent at various metal thicknesses. Furthermore, we found that metamaterials made even from a generally poor metal become highly resonant owing to a drastic increase in the value of the permittivity at terahertz frequencies. 相似文献
997.
We have exactly solved a model of equidistant cascade four-level system interacting with a single-mode radiation field both
semiclassically and quantum mechanically by exploiting its similarity with Jaynes-Cummings model. For the classical field,
it is shown that the Rabi oscillation of the system initially in the first level (second level) is similar to that of the
system when it is initially in the fourth level (third level). We then proceed to solve the quantized version of the model
where the dressed state is constructed using a six-parameter four-dimensional matrix and show that the symmetry exhibited
in the Rabi oscillation of the system for the semiclassical model is completely destroyed on the quantization of the cavity
field. Finally, we have studied the collapse and revival of the system for the cavity field-mode in a coherent state to discuss
the restoration of symmetry and its implication is discussed.
相似文献
998.
We review current research on minerals using inelastic neutron scattering and lattice dynamics calculations. Inelastic neutron
scattering studies in combination with first principles and atomistic calculations provide a detailed understanding of the
phonon dispersion relations, density of states and their manifestations in various thermodynamic properties. The role of theoretical
lattice dynamics calculations in the planning, interpretation and analysis of neutron experiments are discussed. These studies
provide important insights in understanding various anomalous behaviour including pressure-induced amorphization, phonon and
elastic instabilities, prediction of novel high pressure phase transitions, high pressure-temperature melting, etc.
相似文献
999.
Zirconia (ZrO2), yttria (Y2O3) and thorite (ThSiO4) are ceramic materials used for a wide range of industrial applications. The dynamical properties of these materials are
of interest as they exhibit numerous interesting phase transitions at high temperature and pressure. Using a combination of
inelastic neutron scattering and theoretical lattice dynamics we have studied the phonon spectra and thermodynamic properties
of these compounds. The experimental data validate the theoretical model, while the model enables microscopic interpretations
of the observed data. The calculated thermodynamic properties are in good agreement with the experimental data.
相似文献
1000.
NaNbO3 and (Sr,Ca)TiO3 exhibit an unusual complex sequence of temperature- and pressure-driven structural phase transitions. We have carried out
lattice dynamical studies to understand the phonon modes responsible for these phase transitions. Inelastic neutron scattering
measurements using powder samples were carried out at the Dhruva reactor, which provide the phonon density of states. Lattice
dynamical models have been developed for SrTiO3 and CaTiO3 which have been fruitfully employed to study the phonon spectra and vibrational properties of the solid solution (Sr,Ca)TiO3.
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