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761.
Polyamide-6/poly(epichlorohydrin - co - ethylene oxide) (PA6/ECO) nanocomposites were prepared with 6 wt.% organoclay and different ECO content from 5 to 40 wt.%,
via two-step melt blending process. The effects of organoclay and rubber content on the morphological and rheological properties
of samples have been studied. Samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM),
and rheometry in small amplitude oscillatory shear. XRD results indicate that the nanoclay platelets are partially exfoliated
in both PA6 and ECO phases. The higher rubber content of nanocomposite samples results in higher exfoliation degree of the
nanoclay layers. SEM photomicrographs of samples show that the size of rubber droplets increases by the introducing of nanoclay.
Oscillatory shear measurements show that the storage modulus of nanocomposite samples significantly increases in comparison
with unfilled blends. The formation of physical network is the prime cause of such increase. Moreover, presence of nanoclay
dramatically increases melt yield stress of the samples. Palierne emulsion model has been applied to predict the rheological
behavior of unfilled blends. A quantitative agreement between Palierne model and those of experimental data is found for low
ECO content samples. 相似文献
762.
Xinyu Sun Xueyan Feng Xiao-Yun Yan Jiancheng Luo Ruimeng Zhang Tao Li Hui Li Jiahui Chen Fangbei Liu Ehsan Raee Stephen Z. D. Cheng Tianbo Liu 《Chemical science》2021,12(36):12130
We report herein that dendron-shaped macromolecules ABn crystallize into well-ordered pyramid-like structures from mixed solvents, instead of spherical motifs with curved structures, as found in the bulk. The design of the asymmetric molecular architecture and the choice of mixed solvents are applied as strategies to manipulate the crystallization process. In mixed solvents, the solvent selection for the Janus macromolecule and the existence of dominant crystalline clusters contribute to the formation of flat nanosheets. Whereas during solvent evaporation, the bulkiness of the asymmetric macromolecules easily creates defects within 2D nanosheets which lead to their spiral growth through screw dislocation. The size of the nanosheets and the growth into 2D nanosheets or 3D pyramidal structures can be regulated by the solvent ratio and solvent compositions. Moreover, macromolecules of higher asymmetry generate polycrystals of lower orderliness, probably due to higher localized stress.The dendron-shaped macromolecules ABn crystallize into well-ordered pyramid-like structures from mixed solvents, which is on the contrary to spherical motifs with curved structures in bulk. 相似文献
763.
In this study, an efficient hybrid continuum‐atomistic method is proposed to study electrokinetic transport of aqueous solutions in nanofluidics. The aqueous phase is considered as a continuous phase containing immersed ion particles. The behavior of the system is then simulated through utilization of an improved hybrid continuum‐atomistic four‐way coupled approach, including the MultiPhase Particle‐In‐Cell method for the short‐ranged interaction between the ion particles, the Brownian force for the collision between the aqueous phase molecules and the ion particles, and a wall force accounting for the short‐ranged interaction of ions and walls. The validation of the proposed model with the results of Molecular Dynamics simulations suggests that this model can be a promising approach for studying the electrokinetic phenomena in more complicated geometries where the Molecular Dynamics approach is computationally prohibitive. Finally, the effects of electrokinetic parameters, such as the height of the channel, the external electric field, and bulk ionic concentration, on the electroosmotic flow in a nanochannel are investigated and discussed. 相似文献
764.
Saif Ullah Pablo A. Denis Fernando Sato 《International journal of quantum chemistry》2019,119(18):e25975
We investigate, by means of first-principles density functional theory (DFT) calculation, the possibility of using hexagonal boron-arsenide (h-BAs) as an anode material for alkali-based batteries. We show that the adsorption strength of alkali atoms (Li, Na, and K) on h-BAs in comparison with graphene and other related materials changes a little as a function of alkali atom concentration. When the separation between alkali atoms and h-BAs is less than the critical distance of ~5 Å, the adsorption energy abruptly increases showing fast adsorption without an energy barrier. Furthermore, the low energy barriers of 0.322, 0.187, and 0.0.095 eV for Li, Na, and K, respectively, ensure the fast ionic diffusivities for all the three alkali atoms. Additionally, the addition of these alkali atoms transforms the electronic properties of h-BAs from semiconducting to metallic, resulting in improved electronic conductivities. Most interestingly, the excellent storage capacities of h-BAs (~626 mAh/g) for alkali atoms make it a material of similar caliber to that of other popular anode materials. Finally, the average open circuit voltages are calculated and found to be in the desired range. In short, h-BAs possess every quality that is crucial for an anode material and thus it is interesting to see h-BAs in alkali-based battery technologies. 相似文献
765.
In this paper,the magnetohydrodynamic 3 D flow of Prandtl nanoliquid subject to convectively heated extendable surface has been discussed.A linear stretching surface makes the flow.Thermophoretic and Brownian motion impacts are explored.Heat transfer for convective procedure is considered.Prandtl liquid is taken electrically conducted through applied magnetic field.Suitable non-dimensional variables lead to strong nonlinear ordinary differential system.The obtained nonlinear differential systems are solved through optimal homotopic technique.Physical quantities like skin friction coefficients and Nusselt number are explored via plots.It is observed that effects of Hartman parameter and Biot number on temperature and concentration are quite similar.Both temperature and concentration are enhanced for larger values of Hartman parameter and Biot number. 相似文献
766.
Saeed Ullah Jan Sami Ul Haq Syed Inayat Ali Shah Ilyas Khan Muhammad Atif Khan 《理论物理通讯》2019,71(6):647-657
This work is focused on the effect of heat and mass transfer with unsteady natural convection flow of viscous fluid along with ramped wall temperature under the assumption of the slip wall condition at the boundary. Analytical solutions are obtained by using Laplace transformation to the non-dimensional set of governing equations containing velocity, temperature and concentration. Moreover, the expression for skin-friction is derived by differentiating the analytical solutions of fluid velocity. Numerical tables for Skin-friction, Sherwood number and Nusselt-number are examined. For the physical aspects of the flow, we use various values of involved physical parameters such as Prandtl number (Pr), slip parameter ($\eta$), Schmidt number (Sc), buoyancy ratio parameter ($N$), Sherwood number (Sh), and time $(t)$. Additionally, the general solutions are plotted graphically and a comprehensive theoretical section of numerical discussions is included. 相似文献
767.
Bibi A. Shah T. Sadiq A. Khalid N. Ullah F. Iqbal A. 《Russian Journal of Organic Chemistry》2019,55(11):1749-1754
Russian Journal of Organic Chemistry - N-Substituted succinimides having different alkyl groups were prepared by the reaction of N-substituted maleimide with aldehydes. A two-component catalyst... 相似文献
768.
Muhammad Ehsan Ashwani Kumar Jonas S. Mortensen Yang Du Parameswaran Hariharan Kaavya K. Kumar Betty Ha Bernadette Byrne Lan Guan Brian K. Kobilka Claus J. Loland Pil Seok Chae 《化学:亚洲杂志》2019,14(11):1926-1931
We prepared an amphiphile with a penta‐phenylene lipophilic group and a branched trimaltoside head group. This new agent, designated penta‐phenylene maltoside (PPM), showed a marked tendency to self‐assembly into micelles via strong aromatic–aromatic interactions in aqueous media, as evidenced by 1H NMR spectroscopy and fluorescence studies. When utilized for membrane protein studies, this new agent was superior to DDM, a gold standard conventional detergent, in stabilizing multiple proteins long term. The ability of this agent to form aromatic–aromatic interactions is likely responsible for enhanced protein stabilization when associated with a target membrane protein. 相似文献
769.
Ehsan Samei Kimberlee J. Kearfott Timothy J. Gillespie C.-K. Chris Wang 《Radiation Physics and Chemistry》1996,48(6):719-725
A method to generate depth-dose distributions due to beta radiation in LiF and soft tissue is proposed. In this method, the EGS4 Monte Carlo radiation transport code is initially used to generate a library of monoenergetic electron depth-dose distributions in the material for electron energies in the range of 10 keV to 5 MeV in 10 keV increments. A polynomial least-squares fit is applied to each distribution. In addition, a theoretical model is developed to generate beta-ray energy spectra of selected radionuclides. A standard Monte Carlo random sampling technique is then employed to sample the spectra and generate the depth-dose distributions in LiF and soft tissue. The proposed method has an advantage over more traditional methods in that the actual radiation transport in the media is performed only once for a set of monoenergetic cases and the beta depth-dose distributions are easily generated by sampling this previously-acquired database in a matter of minutes. This method therefore reduces the demand on computer resources and time. The method can be used to calculate depth-dose distribution due to any beta-emitting nuclide or combination of nuclides with up to ten beta components. 相似文献
770.
Dikshitulu K. Kalluri Monzurul M. Ehsan 《International Journal of Infrared and Millimeter Waves》2004,25(2):327-353
A frequency transformer that converts an elliptically polarized standing wave into frequency-shifted circularly polarized standing waves is considered. The transformer is a one-dimensional cavity in which a magnetoplasma, that supports longitudinal modes, is created. Theoretical derivation for the case of sudden and uniform creation of the magnetoplasma is given. Finite-Difference Time-Domain (FDTD) technique is developed to numerically simulate the problem. The simulation is used to verify the results of the theory as well as obtain results for the cases of creation of a lossy magnetoplasma with arbitrary space and time profile of the electron density. A few instructive results are presented as graphs to illustrate the effects of source parameters and system parameters. 相似文献