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排序方式: 共有417条查询结果,搜索用时 109 毫秒
71.
Muhammad Danial Hisham Abdul Rauf Dumitru Vieru Aziz Ullah Awan 《Chinese Journal of Physics (Taipei)》2018,56(6):3020-3032
Unsteady flows of two immiscible Maxwell fluids in a rectangular channel bounded by two moving parallel plates are studied. The fluid motion is generated by a time-dependent pressure gradient and by the translational motions of the channel walls in their planes. Analytical solutions for velocity and shear stress fields have been obtained by using the Laplace transform coupled with the finite sine-Fourier transform. These analytical solutions are new in the literature and the method developed in this paper can be generalized to unsteady flows of n-layers of immiscible fluids. By using the Laplace transform and classical method for ordinary differential equations, the second form of the Laplace transforms of velocity and shear stress are determined. For the numerical Laplace inversion, two accuracy numerical algorithms, namely the Talbot algorithm and the improved Talbot algorithm are used. 相似文献
72.
Mihai Cosmin Corobea Oana Muhulet Florin Miculescu Iulian Vaile Antoniac Zina Vuluga Dorel Florea Dumitru Mircea Vuluga Maria Butnaru Daniela Ivanov Stefan Ioan Voicu Vijay Kumar Thakur 《先进技术聚合物》2016,27(12):1586-1595
In this study, a new class of heterogeneous membranes based on cellulose acetate (CA) polymer and a complex filler clay‐silica nanowires (SiO2NWs) was investigated for potential biomedical applications. SiO2NWs were synthesized using natural clay through a facile sol–gel method and were dispersed in the polymer solution by sonication in the 1.25, 2.5, and 5% weight ratio to the CA acetate polymer. Membranes were subsequently prepared via phase inversion by precipitation of the CA polymer in water. The pristine CA membrane and SiO2NWs based nanocomposites membranes were characterized using different characterization techniques. The presence of the SiO2NWs in the CA membrane was found to significantly enhance the protein retention, water wettability and thermal as well as mechanical properties in comparison to the pristine CA membrane. Water flows studies at different temperatures and the retention of bovine serum albumin have been studied and the nanocomposite membranes were found to exhibit superior performances compared with the pristine CA membranes. SiO2NWs‐CA membranes showed a much higher stability to the water temperature change during separation than CA membranes. Morphological changes clearly revealed that the composite membrane were much more compact than the pristine CA membranes. The rabbit dermal fibroblasts cell viability in cultures after 72 hr of incubation was found to be greater than 80%. These newly synthesized composite membranes exhibit a high potential to be used for various medical applications because of their non‐cytotoxic characteristics. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
73.
The present paper deals with the Sharma–Tasso–Olver–Burgers equation (STOBE) and its conservation laws and kink solitons. More precisely, the formal Lagrangian, Lie symmetries, and adjoint equations of the STOBE are firstly constructed to retrieve its conservation laws. Kink solitons of the STOBE are then extracted through adopting a series of newly well-designed approaches such as Kudryashov and exponential methods. Diverse graphs in 2 and 3D postures are formally portrayed to reveal the dynamical features of kink solitons. According to the authors’ knowledge, the outcomes of the current investigation are new and have been listed for the first time. 相似文献
74.
Yingji He Xing Zhu Dumitru Mihalache Jinglin Liu Zhanxu Chen 《Optics Communications》2012,285(15):3320-3324
We study the existence and stability of solitons forming in PT–symmetric optical lattices with spatially periodic modulation of the local strength of the nonlinear media. We found that the spatial modulation of the nonlinearity significantly affects the stability of solitons in PT–symmetric optical lattices. With the decrease of the strength of nonlinear refractive index modulation, the soliton's stability domain increases, whereas with the increase of the period of nonlinear refractive index modulation, the corresponding soliton's stability range narrows. In addition, we also investigate the influence of variation of the amplitude of the linear PT–symmetric lattice potential on soliton dynamics, in the presence of spatially periodic modulation of nonlinearity. 相似文献
75.
Dumitru Popa 《Rendiconti del Circolo Matematico di Palermo》2012,61(3):307-319
We introduce the notion of multilinear nuclear operator with respect to a partition and extend Grothendieck??s characterizations of nuclear linear operators into $l_{1},$ resp. $L_{1}( \mu ),$ in this new setting. We give the necessary and sufficient conditions for a natural operator to be nuclear with respect to a partition. 相似文献
76.
Jeanina Pandele Cusu Adina Magdalena Musuc Mihaela Matache Dumitru Oancea 《Journal of Thermal Analysis and Calorimetry》2012,110(3):1259-1266
In this study, the thermal stability and exothermal decomposition of some ketone-2,4-dinitrophenylhydrazones have investigated using the DSC technique. The synthesized and purified crystalline solids are thermally stable and start to decompose after melting. Non-isothermal DSC curves, recorded at several heating rates, were used to evaluate the melting properties and the kinetics of thermal decomposition. The isoconversional and model-fitting methods were applied to determine the activation parameters from the common analysis of multiple curves measured at different heating rates. Based on the results of the model??free method, a kinetic model was derived, and the kinetic parameters were obtained by means of a multivariate nonlinear regression. The results are discussed in relation to the effect of the ketone structure. 相似文献
77.
Alireza Khalili Golmankhaneh Ali Moslemi Yengejeh Dumitru Baleanu 《International Journal of Theoretical Physics》2012,51(9):2909-2916
The fractional generalization of Hamiltonian mechanics is constructed by using the Lagrangian involving fractional derivatives. In this paper the equation of projectile motion with air friction using fractional Hamiltonian mechanics and equation for current loop involving electric source, a resistor, an inductor and a capacitor has been obtained. Furthermore, fractional optics has been introduced. 相似文献
78.
Sliding observer for synchronization of fractional order chaotic systems with mismatched parameter 总被引:1,自引:0,他引:1
Hadi Delavari Danial M. Senejohnny Dumitru Baleanu 《Central European Journal of Physics》2012,10(5):1095-1101
In this paper, we propose an observer-based fractional order chaotic synchronization scheme. Our method concerns fractional order chaotic systems in Brunovsky canonical form. Using sliding mode theory, we achieve synchronization of fractional order response with fractional order drive system using a classical Lyapunov function, and also by fractional order differentiation and integration, i.e. differintegration formulas, state synchronization proved to be established in a finite time. To demonstrate the efficiency of the proposed scheme, fractional order version of a well-known chaotic system; Arnodo-Coullet system is considered as illustrative examples. 相似文献
79.
We review recent theoretical results concerning the existence, stability and unique features of families of bright vortex
solitons (doughnuts, or ‘spinning’ solitons) in both conservative and dissipative cubic-quintic nonlinear media. 相似文献
80.
The uniaxial in-plane and out-of-plane anisotropies of [Co/SiO2] × 10 multilayers have been studied by ferromagnetic resonance, magnetometry and transmission electron microscopy. The surface and volume anisotropy constants are in the range of values typical for multilayers with Co and transition metals of the iron group. The influence of the intermixed Co-SiO2 region is discussed. 相似文献