排序方式: 共有30条查询结果,搜索用时 421 毫秒
11.
In this paper, we first establish a Poincaré–Lelong type formula in the almost complex setting. Then, after introducing the notion of J -analytic subsets, we study the restriction of a closed positive current defined on an almost complex manifold (M,J) on a J-analytic subset. Finally, we prove that the Lelong numbers of a plurisubharmonic current defined on an almost complex manifold are independent of the coordinate systems. 相似文献
12.
O. Bel Hadj Fredj 《Proceedings of the American Mathematical Society》2007,135(7):2229-2234
In the present note, we study the problem of lifting poles in Calkin algebra on a separable infinite-dimensional complex Hilbert space . We show by an example that such lifting is not possible in general, and we prove that if zero is a pole of the resolvent of the image of an operator in the Calkin algebra, then there exists a compact operator for which zero is a pole of if and only if the index of is zero on a punctured neighbourhood of zero. Further, a useful characterization of poles in Calkin algebra in terms of essential ascent and descent is provided.
13.
M. Debbichi A. Ben Fredj A. Bhouri N. Bouarissa M. Said 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(1):17-23
Taking into account the recent advances in the epitaxial growth of
single-crystal InN leading to a drastic re-evaluation of its fundamental
energy band gap, we have studied the electronic properties of
InNxP1-x (x < 0.01) ternary alloy. Using the empirical
pseudopotential method under the virtual crystal approximation, combined
with the Harrison bond orbital model, the band gap at Γ, X and L
points, the effective masses of the Γ valley and the electronic
charge densities are calculated as a function of nitrogen composition. The
fitted expressions of the energy band gaps indicate that the bowing
parameter at Γ reached a broad value for very low nitrogen
incorporation (
).
Furthermore, the band gap at Γ point decreases drastically with
increasing nitrogen composition up to 1%. The elastic constants and the
optical phonon frequencies are also reported. Our theoretical results
provide a good agreement with the available data. 相似文献
14.
Labeled magnetic nanoparticles assembly on polypyrrole film for biosensor applications 总被引:1,自引:0,他引:1
In recent years, conducting polymers combined with metallic nanoparticles have been paid more attention due to their potential applications in microelectronics, microsystems, optical sensors and photoelectronic chemistry. The work presented in this paper describes the preparation and characterization of a nanocomposite composed by a thin polypyrrole (PPy) film covered with an assembly of magnetic nanoparticles (NPs). The magnetic particles were immobilized on PPy films under appropriate magnetic field in order to control their organization on the PPy film and finally to improve the sensitivity of the system in potential sensing applications. The electrical properties and morphology of the resulting PPy film and the PPy film/NPs composite were characterized with cyclic voltammetry, impedance spectroscopy (IS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and infra-red spectroscopy (IR). By using streptavidin labeled magnetic particles it was possible to functionalize the NPs assembly with biotin-Fab fragment K47 antibody. The designed biosensor had been successfully applied in rapid, simple, and accurate measurements of atrazine concentrations, with a significantly low detection limit of 5 ng/ml. 相似文献
15.
M. C. Abreu C. Baglin A. Baldisseri A. Baldit C. Barrière M. Bedjidian P. Bordalo A. Bussière P. Busson R. Cases J. Castor T. Chambon C. Charlot B. Chaurand D. Contardo E. Descroix A. Devaux O. Drapier J. Fargeix X. Felgeyrolles R. Ferreira P. Force L. Fredj J. M. Gago C. Gerschel P. Gorodetzky B. Grosdidier J. Y. Grossiord A. Guichard J. P. Guillaud R. Haroutunian D. Jouan L. Kluberg R. Kossakowski G. Landaud P. Liaud C. Lourenço S. Papillon L. Peralta J. R. Pizzi C. Racca S. Ramos A. Romana R. A. Salmeron P. Sonderegger F. Staley S. Silva X. Tarrago J. Varela F. Vazeille 《Zeitschrift fur Physik C Particles and Fields》1992,55(3):365-371
Meson production in proton, oxygen and sulphur interactions with uranium targets at 200 GeV/nucleon is studied. We measure the inclusive meson cross-section d /dP
T
2
and its evolution fromp+U to S+U. The cross-section fitted with an exponential gives an inverse slopeP
T0 of the order of 210 MeV/c. As a function of the neutral transverse energy,P
T0 values show a slight rise followed by a plateau. The normalized difference (+––)/– between positive and negative meson cross-sections is found to increase withE
T
.also at ISEL 相似文献
16.
Y. Oussaifi A. Said A. Ben Fredj L. Debbichi D. Ceresoli M. Said 《Physica B: Condensed Matter》2012,407(17):3604-3609
Using the Empirical Pseudopotential Method (EPM) combined with an improved Virtual Crystal Approximation (VCA), where the effect of compositional disorder is included as an effective periodic potential, we have calculated the electronic band structure of GaN and AlN under hydrostatic pressure up to 200 kbar and 160 kbar, respectively. The behavior of electronic properties of their alloys AlxGa1−xN in the wurtzite structure have been predicted at zero pressure, for the entire range of alloy concentrations. 相似文献
17.
Fredj ELKHADHRA 《数学物理学报(B辑英文版)》2013,33(6):1652-1666
In this paper we give a new definition of the Lelong-Demailly number in terms of the CT-capacity, where T is a closed positive current and CT is the capacity associated to T. This derived from some esimate on the growth of the CT-capacity of the sublevel sets of a weighted plurisubharmonic (psh for short) function. These estimates enable us to give another proof of the Demailly's comparaison theorem as well as a generalization of some results due to Xing concerning the characterization of bounded psh functions. Another problem that we consider here is related to the existence of a psh function v that satisfies the equality CT(K) : fK T ∧ (dd^cu)^p, where K is a compact subset. Finally, we give some conditions on the capacity CT that guarantees the weak convergence ukTk → uT, for positive closed currents T, Tk and psh functions uk, u. 相似文献
18.
19.
Computing stock price comovements with a three-regime panel smooth transition error correction model
Jawadi Fredj Chlibi Souhir Cheffou Abdoulkarim Idi 《Annals of Operations Research》2019,274(1-2):331-345
Annals of Operations Research - This paper studies the hypothesis of stock price comovements toward the US market for a large sample of developed and emerging stock markets (G6, BRICS, and MENA)... 相似文献
20.
A new algorithm is presented for finding the global minimum, and other low-lying minima, of a potential energy surface (PES) of biological molecules. The algorithm synergetically combines three well-known global optimization methods: the diffusion equation method (DEM), which involves smoothing the PES; a simulated annealing (SA) algorithm; and evolutionary programming (EP), whose population-oriented approach allows for a parallel search over different regions of the PES. Tests on five peptides having between 6 and 9 residues show that the code implementing the new combined algorithm is efficient and is found to outperform the constituent methods, DEM and SA. Results of the algorithm, in the gas phase and with the GBSA implicit solvent model, are compared with crystallographic data for the test peptides; good accord is found in all cases. Also, for all but one of the examples, our hybrid algorithm finds a minimum deeper than those obtained by a very extensive scan. TINKERs implementation of the OPLS-AA force field is employed for the structure prediction. The results show that the new algorithm is a powerful structure predictor, when a reliable potential function is available. Our implementation of the algorithm is time-efficient, and requires only modest computational resources. Work is underway on applications of the new algorithm to structural prediction of proteins and other biological macro-molecules. 相似文献