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21.
Alexandros Patsourakos 《代数通讯》2013,41(3):927-932
The free Lie, right, and left Leibniz algebras are obtained as quotients of the free nonassociative algebra by suitable ideals. In this article, we prove some remarkable properties of these ideals. 相似文献
22.
Alexandros Kyriakides Evdokia Kastanos Katerina Hadjigeorgiou Costas Pitris 《Journal of Raman spectroscopy : JRS》2011,42(5):904-909
The classification of Raman spectra can be very useful in a wide range of diagnostic applications including bacterial identification. Before any form of classification can be carried out on the Raman spectra, some form of pre‐processing is commonly applied. This pre‐processing greatly affects the accuracy of the results and introduces user bias and over‐fitting effects. In this paper, we propose using support vector machines with the correlation kernel. The use of the correlation kernel on Raman spectra has not been presented before in any published work. Our results illustrate that the correlation kernel is ‘self‐normalizing’ and produces superior classification performance with minimal pre‐processing, even on highly noisy data obtained using inexpensive equipment. Such effective classification approaches can lead to clinically valuable diagnostic applications of Raman Spectroscopy. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
23.
A series of iPP/SiO2 nanocomposites, containing 1, 2.5, 5, 7.5, and 10 wt.‐% fumed silica nanoparticles, were prepared by melt mixing in a twin screw co‐rotating extruder. The effect of different extrusion parameters was evaluated. The size of aggregates increased with increase in SiO2 content and repetition of the mixing process improved the filler's dispersion. A similar effect was also exhibited by either increasing the rotor speed or the mixing temperature, with the latter being more pronounced at the ranges studied. The mechanical properties of the prepared nanocomposites were evaluated and various models used to explain the observed enhancements. However, only the three‐phase model could provide some correlation with the experimental results. All nanocomposites displayed lower permeability to gases.
24.
Maria Soutzidou Alexandros Panas Kyriakos Viras 《Journal of Polymer Science.Polymer Physics》1998,36(15):2805-2810
Poly(dimethylsiloxane) was studied by laser Raman spectroscopy and differential scanning calorimetry. The Si O Si skeletal mode at 489 cm−1 and the C Si C deformation bands at 188 cm−1 and 158 cm−1 were studied as functions of temperature from ambient to −130°C, and effects of temperature interpreted in accordance with results from thermal analysis. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2805–2810, 1998 相似文献
25.
26.
Alexandros G. Koutsioubas Nikolaos Spiliopoulos Dimitris L. Anastassopoulos Alexandros A. Vradis George D. Priftis 《Surface and interface analysis : SIA》2009,41(11):897-903
The formation process of n‐alkane phosphonic acid CH3 (CH2)n?1 PO(OH)2 (n = 10,12,14,18) self‐assembled monolayers (SAMs), deposited from ethanol solutions on aluminum oxide, has been monitored in situ using surface plasmon resonance (SPR) spectroscopy. In addition, the two‐solvent approach is used to obtain both film thickness and refractive index of the fully formed adsorbed layers. A densely packed adsorbed layer is formed only for the longest molecules with n = 18. The chain length and solution concentration dependence of formation kinetics are studied, and the existence of two distinct kinetic steps is revealed. Fittings of the experimental results with various kinetic models are performed. Our analysis suggests that during the first kinetic step, a transition from a lying‐down to a standing‐up phase takes place, and the growth of this standing‐up phase is governed by second‐order kinetics. The second slow kinetic step is described by a modified first‐order Langmuir law. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
27.
Diamantidis C. Alexandros Papadopoulos T. Chrissoleon 《European Journal of Operational Research》2009
This paper examines a model of a serial flow line with two workstations and an intermediate buffer. Each workstation consists of multiple unreliable parallel machines which are not necessarily identical, viz., the processing times, failure times and repair times of the parallel machines at each workstation are assumed to be exponentially distributed with non-identical mean rates. The system under consideration is solved via exact Markovian analysis. More specifically, a recursive algorithm that generates the transition matrix for any value of the intermediate buffer capacity is developed and all possible transition equations are derived and solved analytically. Once the transition equations are solved the performance measures of the model under consideration can be easily evaluated. This model may be used as a decomposition block for solving larger flow lines with parallel unreliable machines at each workstation. 相似文献
28.
Self-organization and pattern formation of janus particles in two dimensions by computer simulations
Vanakaras AG 《Langmuir : the ACS journal of surfaces and colloids》2006,22(1):88-93
The phase behavior and associated pattern formation of two-dimensional systems of hard disks decorated with amphiphilic coronae (Janus disks) are studied by means of Monte Carlo computer simulations. A primitive interaction potential that captures the essential interparticle interactions is introduced. Despite its simplicity, the system exhibits a very rich phase polymorphism. Apart from the isotropic phase and depending upon the coronal thickness, the simulated systems self-organize in a number of two-dimensional mesophases of various symmetries exhibiting a variety of novel patterns. The results of these simulations suggest that 2D Janus particles are promising candidates for bottom-up design of precise two-dimensional templates. 相似文献
29.
Alexandros Dimitriadis Nikolaos Kantartzis Theodoros Tsiboukis 《Applied Physics A: Materials Science & Processing》2012,109(4):1065-1070
An enhanced metamaterial absorber based on the circumscribed-cross resonator is introduced in this paper. The new structure is polarization-independent, due to the symmetry of its unit cell, and is proven efficient for the attenuation of obliquely incident waves. The absorption mechanism is thoroughly investigated and is found to be mainly related to the losses of the dielectric substrate. Furthermore, by exploiting the scalability property of metamaterials, the operational bandwidth of our design can be drastically improved by placing unit cells with properly scaled resonators adjacent to each other. In this context, various combinations of three, four, and nine unit cells that can increase the full width at half maximum up to as much as 11.18?%, are developed. The overall performance of the proposed configurations is deemed promising for the realization of microwave metamaterial absorbers for several practical applications. 相似文献
30.
Alexandros Avdis Sylvain Lardeau Michael Leschziner 《Flow, Turbulence and Combustion》2009,83(3):343-370
Large Eddy Simulations for two flows separating from a two-dimensional hump in a duct are reported and discussed. The flows
differ through the presence or absence of a synthetic slot-jet injected in a sinusoidal manner, i.e. at zero net mass-flow
rate, close to the location of separation and intended to reduce (“control”) the extent of the separated region. Results reported
include instantaneous visualisations, pre-multiplied spectra, wall-pressure distributions, streamfunction fields and profiles
of velocity and second moments. For both flows, agreement between the simulations and the experimental results is generally
good, especially in respect of the overall control effectiveness of the synthetic jet, despite the use of an approximate wall
treatment bridging the viscous sublayer. Proper Orthogonal Decomposition of the velocity field is used to study structural
features, and this shows that the most energetic mode in the base flow is representative of large streamwise vortices in the
separated region, while in the controlled flow, most of the energetically dominant modes are associated with large spanwise
vortices. 相似文献