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Supposa that f(x) is a quasidifferentiable function, defined on S(?)R~n where S is an open set, with a -equivalent bounded quasidifferential subfam ily. Lenma I 相似文献
4.
Q. Sun Q. Wang X.G. Gong V. Kumar Y. Kawazoe 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):77-81
We report results of the atomic and electronic structures of Al7C cluster using ab initio molecular dynamics with ultrasoft pseudopotentials and generalized gradient approximation. The lowest energy structure is
found to be the one in which carbon atom occupies an interstitial position in Al7 cluster. The electronic structure shows that the recent observation [Chem. Phys. Lett. 316, 31 (2000)] of magic behavior of Al7C- cluster is due to a large highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) gap which makes Al7C- chemically inert. These results have further led us to the finding of a new neutral magic cluster Al7N which has the same number of valence electrons as in Al7C- and a large HOMO-LUMO gap of 1.99 eV. Further, calculations have been carried out on (Al7N)2 to study interaction between magic clusters.
Received 28 July 2001 相似文献
5.
Q. B. Li 《Optics and Lasers in Engineering》1989,11(2)
The smoothing spline function has been used for differentiation of photomechanical data in experimental stress analysis. However, since the available software packages use the algorithm with the so-called natural boundary conditions which are not necessarily suitable in many circumstances, errors tend to occur in both the first and second derivatives. In this paper we have modified the algorithm so that the user can have more freedom in selecting boundary conditions which suit the problem best and therefore, as a result, improve the accuracy of the analysis. Two examples are given to show the improvement achievable using the new scheme. 相似文献
6.
Inspired by the recent work [HHM03], we prove two stability results for compact Riemannian manifolds with nonzero parallel spinors. Our first result says that Ricci flat metrics which also admit nonzero parallel spinors are stable (in the direction of changes in conformal structures) as the critical points of the total scalar curvature functional. Our second result, which is a local version of the first one, shows that any metric of positive scalar curvature cannot lie too close to a metric with nonzero parallel spinor. We also prove a rigidity result for special holonomy metrics. In the case of SU(m) holonomy, the rigidity result implies that scalar flat deformations of Calabi-Yau metric must be Calabi-Yau. Finally we explore the connection with a positive mass theorem of [D03], which presents another approach to proving these stability and rigidity results. Dedicated to Jeff Cheeger for his sixtieth birthday 相似文献
7.
本文提出从高分辨电子显微像中,利用光学、全息和部分相干等方法,提取传递函数,制作相位和振幅滤波器,实现解卷,提高高分辨电子显微像的分辨率. 相似文献
8.
Tereza C. R. dos Santos Ricardo Q. Aucélio Reinaldo C. Campos 《Mikrochimica acta》2003,142(1-2):63-66
A simple and direct spectrofluorimetric method has been developed for the determination of aluminum using alizarin red PS
(1,2,4-trihydroxy 9,10-anthraquinone-3-sulfonic acid). The method is based on the strong fluorescence (480/564 nm) of Al3+ and alizarin red. Experimental parameters such as pH, concentration of the ligand, ionic strength of the solution, reaction
time and temperature were optimized in order to maximize the analytical signal. Interferences of several ions (anions and
cations) were studied and evaluated. The linear range of the method extends from 3 to 100 μg L−1. Limit of detection (3sb) was 0.9 μg L−1. The method was tested with a silicate certified reference material. Interferences were eliminated by a liquid extraction
with cupferron.
Author for correspondence. E-mail: aucelior@rdc.puc-rio.br
Received September 10, 2002; accepted January 15, 2003
Published online May 5, 2003 相似文献
9.
K.B. Welter Q. Wu Y. You K. Abel D. McCreary S.M. Bajorek J.N. Reyes Jr 《International Journal of Multiphase Flow》2004,30(12):407-1484
This article describes a comprehensive literature review of liquid entrainment in horizontal pipes with vertical-up branches. Deficiencies in the available data and correlations were identified. The Air–water Test Loop for Advanced Thermal–hydraulic Studies (ATLATS) was constructed and entrainment onset and steady-state data were collected for a wide range of flow conditions. Using new insights gained from experimental testing, the authors developed a model for predicting the onset of entrainment and steady-state entrainment rate. Previously published correlations, along with the new model, are compared against all available data. The new model shows very good agreement with the onset data, but is not very good at predicting branch quality at high liquid flow rates. 相似文献
10.
For vector quasivariational inequalities involving multifunctions in topological vector spaces, an existence result is obtained without a monotonicity assumption and with a convergence assumption weaker than semicontinuity. A new type of quasivariational inequality is proposed. Applications to quasicomplementarity problems and traffic network equilibria are considered. In particular, definitions of weak and strong Wardrop equilibria are introduced for the case of multivalued cost functions. 相似文献