oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Microwave and millimeterwave electrical permittivity of graphene monolayer  [PDF]
Alina Cismaru,Mircea Dragoman,Adrian Dinescu,Daniela Dragoman,G. Stavrinidis,G. Konstantinidis
Physics , 2013,
Abstract: The effective electrical permittivity of a graphene monolayer is experimentally investigated in the 5-40 GHz range, which encompasses the microwave and the lower part of millimeterwave spectrum. The measurements were carried out using a coupled coplanar waveguide placed over a graphene monolayer flake, which is deposited on Si/SiO2. In contrast to some initial predictions, the effective permittivity of the graphene monolayer is slightly decreasing in the above-mentioned frequency range and has an average value of 3.3.
Distributed Association Control and Relaying in MillimeterWave Wireless Access Networks  [PDF]
Yuzhe Xu,George Athanasiou,Carlo Fischione,Leandros Tassiulas
Computer Science , 2013,
Abstract: In millimeterWave wireless networks the rapidly varying wireless channels demand fast and dynamic resource allocation mechanisms. This challenge is hereby addressed by a distributed approach that optimally solves the fundamental resource allocation problem of joint client association and relaying. The problem is posed as a multi assignment optimization, for which a novel solution method is established by a series of transformations that lead to a tractable minimum cost flow problem. The method allows to design distributed auction solution algorithms where the clients and relays act asynchronously. The computational complexity of the new algorithms is much better than centralized general-purpose solvers. It is shown that the algorithms always converge to a solution that maximizes the total network throughput within a desired bound. Both theoretical and numerical results evince numerous useful properties in comparison to standard approaches and the potential applications to forthcoming millimeterWave wireless access networks.
Auction-based Resource Allocation in MillimeterWave Wireless Access Networks  [PDF]
George Athanasiou,Pradeep Chathuranga Weeraddana,Carlo Fischione
Computer Science , 2013,
Abstract: The resource allocation problem of optimal assignment of the clients to the available access points in 60 GHz millimeterWave wireless access networks is investigated. The problem is posed as a multiassignment optimisation problem. The proposed solution method converts the initial problem to a minimum cost flow problem and allows to design an efficient algorithm by a combination of auction algorithms. The solution algorithm exploits the network optimization structure of the problem, and thus is much more powerful than computationally intensive general-purpose solvers. Theoretical and numerical results evince numerous properties, such as optimality, convergence, and scalability in comparison to existing approaches.
Emergence of the stochastic resonance in glow discharge plasma  [PDF]
Md Nurujjaman,A N Sekar Iyengar,P Parmananda
Physics , 2009, DOI: 10.1088/1742-6596/208/1/012084
Abstract: stochastic resonance, glow discharge plasma, excitable medium, absolute mean difference
Eft for DFT  [PDF]
R. J. Furnstahl
Physics , 2007, DOI: 10.1007/978-3-642-27320-9_3
Abstract: These lectures give an overview of the ongoing application of effective field theory (EFT) and renormalization group (RG) concepts and methods to density functional theory (DFT), with special emphasis on the nuclear many-body problem.
Effect of Waveform Parameters on Pulsed Glow Discharge in Air  [PDF]
Fengbo Tao, Zhicheng Zhou, Yong Ma, Qiaogen Zhang
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.330207
Abstract: The nanosecond single pulse was employed here to generate a large volume glow discharge between the wire-plane electrodes in air. In order to find requirements on pulse waveform for generation of a large volume discharge at atmospheric pressure, the effect of pulse risetime, pulse width, and amplitude on glow discharge has been widely investigated in this paper. Results reveal that a large volume glow discharge can be generated in an inhomogeneous electric field under the single pulse with the faster risetime, the lower peak amplitude. The pulse width has almost no influence on the density of glow discharge, but which has a great influence on the transition from glow discharge to streamer discharge. A model of inter-shielding-effect has been proposed to explain the influence of waveform parameters on pulsed glow discharge.
Plasma-Based Graphene Functionalization in Glow Discharge  [PDF]
X. Fang, J. Donahue, A. Shashurin, M. Keidar
Graphene (Graphene) , 2015, DOI: 10.4236/graphene.2015.41001
Abstract:
Glow discharge was utilized to add oxygen functional groups to the graphene platelets sample produced in chemical exfoliation synthesis. It was concluded based on Raman spectra that the graphene sample treated with the glow discharge preserves specific graphene features while no transformation to amorphous carbon is happening. SEM and EDS results indicated the increases of oxygen content in the graphene sample after the exposure to the glow discharge. Raman spectra also support the fact that the graphene platelets have been decorated with oxygen as the result of the glow discharge treatment.
Consecutive Three-Component Synthesis of 3-(Hetero)Aryl-1H-pyrazoles with Propynal Diethylacetal as a Three-Carbon Building Block  [PDF]
Lucilla Levi,Christina Boersch,Charlotte F. Gers,Eugen Merkul,Thomas J. J. Müller
Molecules , 2011, DOI: 10.3390/molecules16119340
Abstract: A novel consecutive three-component synthesis of 3-(hetero)aryl-1H-pyrazoles via room temperature Sonogashira arylation of propynal diethylacetal used as a propargyl aldehyde synthetic equivalent has been disclosed. The final acetal cleavage-cyclocondensation with hydrazine hydrochloride at 80 °C rapidly furnishes the title compounds in a one-pot fashion.
The glow of Fourier matrices: universality and fluctuations  [PDF]
Teodor Banica
Mathematics , 2014,
Abstract: The glow of an Hadamard matrix $H\in M_N(\mathbb C)$ is the probability measure $\mu\in\mathcal P(\mathbb C)$ describing the distribution of $\varphi(a,b)=$, where $a,b\in\mathbb T^N$ are random. We prove that $\varphi/N$ becomes complex Gaussian with $N\to\infty$, and that the universality holds as well at order 2. In the case of a Fourier matrix, $F_G\in M_N(\mathbb C)$ with $|G|=N$, the universality holds up to order 4, and the fluctuations are encoded by certain subtle integrals, which appear in connection with several Hadamard-related questions. In the Walsh matrix case, $G=\mathbb Z_2^n$, we conjecture that the glow is polynomial in $N=2^n$.
Hydrodynamics of GRB After-Glow  [PDF]
Re'em Sari
Physics , 1997,
Abstract: The detection of delayed emission at X-ray optical and radio wavelengths, ``after-glow'', suggests that the relativistic shell which emitted the initial GRB due to internal shocks decelerates on encountering an external medium, giving rise to the after-glow. At a very early stage (few seconds), the observed bolometric luminosity increases as t^2. On longer time scales (more than about 10s), the luminosity drops as t^{-1}. If the main burst is long enough, an intermediate stage of constant luminosity will form. In this case, the after-glow overlaps the main burst, otherwise there is a time separation between the two. On the long time scale, the flow decelerate in a self similar way, reaching non relativistic velocities after about 30days. Due to the deceleration and the accumulation of ISM material, the relation between the observed time, the shock radius, and its Lorentz factor, is given by t=R/16\gamma^2c which is a factor of 8 different from the usual expression. The majority of particles are those of the original ejecta (and not the ISM) up to about 900s. These particles reach sub-relativistic velocities on a time scale of about 2hours, well before the flow becomes sub-relativistic. Therefore the ejecta particles are probably unimportant for most of the after-glow radiation. We show that even though only a small fraction of the energy is given to the electrons, most of the energy can be radiated over time. If this fraction is greater than 10% radiation losses will significantly influence the hydrodynamical evolution at early times (less than 1day).
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.