Search results for "PROPAGATION"
showing 10 items of 676 documents
Time dispersion characterization for UWB mobile radio channels between 3.1 and 10.6 GHz
2007
In this paper, a characterization of the UWB mobile radio channel time dispersion is presented. The results provided were obtained from a measurement campaign carried out in a typical indoor office scenario in the band from 3.1 to 10.6 GHz. Time dispersion metrics as delay spread, coherence bandwidth, delay interval and delay window, in both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions are provided.
Observation d'effets Kerr d'ordres élevés (HOKE) dans les gaz
2011
Talk given by O. Faucher; National audience
Diene-Containing Half-Sandwich MoIII Complexes as Ethylene Polymerization Catalysts: Experimental and Theoretical Studies
2001
International audience; Seventeen-electron compounds of Mo III having the general formula [(h 5-C 5 R 5)Mo(h 4-diene)X 2 ] (R H, Me; diene butadiene, iso-prene, or 2,3-dimethylbutadiene; X Cl, CH 3) are a new class of ethylene polymerization catalysts. The polyethy-lene obtained shows a bimodal distribution , the major weight fraction being characterized by very long (M around 10 6) and highly linear polymer chains. The newly prepared pentamethylcyclo-pentadienyl (Cp*) derivatives are more active than the cyclopentadienyl (Cp) derivatives, but much less active than previously investigated niobium III compounds having the same stoichiometry. On the other hand, the turnover frequency of the a…
Recovering Genetic Resources of Some Legume Species of Latvian Origin by Plant Tissue Culture
2013
Accessions with no germinating seeds are a common problem in plant gene banks and research institutions. Our goal was to elaborate and apply an in vitro method of germination and multiplication of old aged seeds of red and alsike clover and alfalfa. Eighteen clover and five alfalfa accessions were used for germination in vitro. Most of the accessions had produced seeds more than 20 years ago and the seeds did not germinate in soil. Seed pre-treatment with different concentrations of potassium permanganate, as well as addition of phytohormones, AgNO3 and activated carbon to germinating media were tested. Plantlets for all germinated accessions were obtained, even in the case when seeds were …
In vitro multiplication ofVella lucentina M. B. crespo (Brassicaceae), a threatened Spanish endemic species
1995
Vella lucentina M. B. Crespo is a threatened Spanish species that is endemic to a small area in eastern Alicante Province (SE Spain). Micropropagation techniques were applied forex situ conservation of this plant. Aseptic epicotyls bearing the apical bud were grown in Murashige and Skoog medium supplemented with 6-furfurylaminopurine (Kin), N6-benzyladenine (BA) or 6-(γ,γ,-dimethilalylamino) purine (2iP). High multiplication rates were obtained with 0.5, 1, or 2 mg·liter−1 BA, or 1 or 2 mg·liter−1 2iP. Indole-3-acetic acid and indole-3-butyric acid were utilized for rooting in half-strength Murashige and Skoog medium. Regenerated plants were transferred to a potting mix and gradually acclim…
Factors affectingin vitro shoot proliferation ofMyrtus communis L.: A comparison of adult and seedling material
1998
Two stocks of shoots growingin vitro, obtained from either seedlings or adult plants, were used to study the effects of material origin, the number of previous subcultures on the establishment medium, the explant type, and the macronutrients on shoot multiplication and elongation inMyrtus communis L., always in the presence of 4.4. μM benzyladenine (BA). Shoot proliferation was influenced mainly by stock origin, with higher responses from the adult material than from the seedling material, and by the number of subcultures, with the largest rates of multiplication and elongation in the first subculture. In the first subculture, the adult material was characterized by high rates of shoot mult…
Direction-dependent elastic properties and phononic behavior of PMMA/BaTiO 3 nanocomposite thin films
2017
Determination of the anisotropic mechanical properties of nanostructured hybrid films is of great importance to improve fabrication and to enable reliable utility. Here, we employ spontaneous Brillouin light spectroscopy to record the phononic dispersion relation along the two symmetry directions in a supported PMMA (poly(methylmethacrylate))-BaTiO3 hybrid superlattice (SL) with a lattice constant of about 140 nm. Several dispersive elastic modes are resolved for in-plane wave propagation, whereas along the periodicity direction the SL opens a wide propagation stop band for hypersonic phonons and near UV photons both centered at about 280 nm. A thorough theoretical analysis based on the fin…
Energy Efficiency Evaluation of Cellular Networks Based on Spatial Distributions of Traffic Load and Power Consumption
2013
Energy efficiency has gained its significance when service providers' operational costs burden with the rapidly growing data traffic demand in cellular networks. In this paper, we propose an energy efficiency model for Poisson-Voronoi tessellation (PVT) cellular networks considering spatial distributions of traffic load and power consumption. The spatial distributions of traffic load and power consumption are derived for a typical PVT cell, and can be directly extended to the whole PVT cellular network based on the Palm theory. Furthermore, the energy efficiency of PVT cellular networks is evaluated by taking into account traffic load characteristics, wireless channel effects and interferen…
Mutual-information based rate-adaptation for Multi-User TH-IR-UWB coded system
2011
In this paper we present a coding rate adaptation technique for a Time-Hopping Impulse-Radio Ultra-Wide Band (TH-IR-UWB) system assuming that the Multi-User Interference (MUI) is modeled as an additive interference noise following a Generalized Gaussian Distribution (GGD). The shape parameter induced by the GGD model is in general time-variant since it strongly depends on the essential UWB system parameters and the received signal power of the active users. In this paper, we show that the performance of a TH-IR-UWB LDPC coded system is quite independent of the GGD shape parameter when we consider the mutual information between the soft input to the decoder and the transmitted sequence, espe…
A narrowband MIMO car-to-car channel model based on the geometrical street scattering model
2012
In this paper, we model a narrowband multiple-input multiple-output (MIMO) car-to-car (C2C) channel model based on the geometrical street scattering model. Starting from the geometrical model, a MIMO reference channel model is derived under the assumption of single-bounce scattering in line-of-sight (LOS) and non-LOS (NLOS) propagation environments. In the proposed channel model, an infinite number of scatterers are uniformly distributed in rectangular grids located on both sides of the street. Analytical solutions are presented for the three-dimensional (3D) space-time cross-correlation function (CCF), the temporal autocorrelation function (ACF), and the two-dimensional (2D) space CCF. An …