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991.
992.
993.
The ZEUS Collaboration S. Chekanov et al. 《The European Physical Journal C - Particles and Fields》2003,28(2):175-201
Cross sections for e-p neutral current deep inelastic scattering have been measured at a centre-of-mass energy of 318 GeV using an integrated luminosity
of 15.9 pb-1 collected with the ZEUS detector at HERA. Results on the double-differential cross-section in the range 185 < Q
2
< 50 000 GeV2 and 0.0037 < x < 0.75, as well as the single-differential cross-sections , and for Q
2
> 200 GeV2, are presented. To study the effect of Z-boson exchange, has also been measured for Q
2
> 10 000 GeV2. The structure function xF3 has been extracted by combining the e-p results presented here with the recent ZEUS measurements of e+p neutral current deep inelastic scattering. All results agree well with the predictions of the Standard Model.
Received: 2 August 2002 / Revised version: 30 January 2003 / Published online: 24 March 2003 相似文献
994.
M. El Assaid M’hamed El Aydi M. El Feddi Françis Dujardin 《Central European Journal of Physics》2008,6(1):97-104
The problem of a shallow donor impurity located at the centre of a symmetrical paraboloidal quantum dot (SPQD) is solved exactly. The Schrödinger equation is separated in the paraboloidal coordinate system. Three different cases are discussed for the radial-like equations. For a bound donor, the energy is negative and the solutions are described by Whittaker functions. For a non-bound donor, the energy is positive and the solutions become coulomb wave functions. In the last case, the energy is equal to zero and the solutions reduce to Bessel functions. Using the boundary conditions at the dot surfaces, the variations of the donor kinetic and potential energies versus the size of the dot are obtained. The problem of a shallow donor impurity in a Hemiparaboloidal Quantum dot (HPQD) is also studied. It is shown that the wave functions of a HPQD are specific linear combinations of those of a SPQD. 相似文献
995.
996.
L. Ferreira-Mendonça V. L. R. Lopes J. M. Martínez 《Computational Optimization and Applications》2008,40(3):373-388
Optimality (or KKT) systems arise as primal-dual stationarity conditions for constrained optimization problems. Under suitable
constraint qualifications, local minimizers satisfy KKT equations but, unfortunately, many other stationary points (including,
perhaps, maximizers) may solve these nonlinear systems too. For this reason, nonlinear-programming solvers make strong use
of the minimization structure and the naive use of nonlinear-system solvers in optimization may lead to spurious solutions.
Nevertheless, in the basin of attraction of a minimizer, nonlinear-system solvers may be quite efficient. In this paper quasi-Newton
methods for solving nonlinear systems are used as accelerators of nonlinear-programming (augmented Lagrangian) algorithms,
with equality constraints. A periodically-restarted memoryless symmetric rank-one (SR1) correction method is introduced for
that purpose. Convergence results are given and numerical experiments that confirm that the acceleration is effective are
presented.
This work was supported by FAPESP, CNPq, PRONEX-Optimization (CNPq / FAPERJ), FAEPEX, UNICAMP. 相似文献
997.
998.
Aybüke A. İsbir Turan Zafer Üstündağ Ali Osman Solak Emine Kılıç Ayça Avseven 《Electroanalysis》2008,20(15):1665-1670
This work describes the characterization of the grafted 2‐benzo[c]cinnoline (2BCC) molecules at a glassy carbon (GC) electrode surface by voltammetry and spectroscopy. Attachment of the molecule to the carbon substrate was achieved by the electrochemical reduction of 2‐benzo[c]cinnoline diazonium salt (2BCC‐DAS). GC electrode modification was carried out in aprotic solution with 2BCC diazonium salt. Dopamine (DA) and ascorbic acid (AA) were used to prove the surface modification to see the blockage of the electron transfer. The presence of 2BCC at the GC electrode surface was characterized by cyclic voltammetry and Raman spectroscopy. Raman spectroscopy was used to monitor molecular bound properties of the adsorbates at the 2BCC‐GC surface and confirm the attachment of 2BCC molecules onto the GC surface. The thickness of the 2BCC film on GC was also investigated by ellipsometric measurement. 相似文献
999.
1000.
W. Czysz F. Jancik J. S. Dunnett W. Schmidt B. R. Glutz et al. 《Fresenius' Journal of Analytical Chemistry》1988,332(5):480-485