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71.
Dimitris Tsiourvas C. M. Paleos Angelos Malliaris 《Journal of polymer science. Part A, Polymer chemistry》1993,31(2):387-393
Selected polyamphiphiles were prepared by the method of reactive polymers, i.e., interaction of polymaleic anhydride and polyacryloyl chloride with certain long chain alcohols. The aggregational behavior of these polyamphiphiles in water was studied by video-enhanced differential interference contrast microscopy, as well as by absorption and fluorescence spectroscopy. The formation of large aggregates was observed by video technique, while inter- and intramolecular micelles were detected by spectroscopic © 1993 John Wiley & Sons, Inc. 相似文献
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We derive pomeron vertex operators for bosonic strings and superstrings in the presence of D-branes. We demonstrate how they can be used in order to compute the Regge behavior of string amplitudes on D-branes and the amplitude of ultrarelativistic D-brane scattering. After a lightning review of the BCFW method, we proceed in a classification of the various BCFW shifts possible in a field/string theory in the presence of defects/D-branes. The BCFW shifts present several novel features, such as the possibility of performing single particle momentum shifts, due to the breaking of momentum conservation in the directions normal to the defect. Using the pomeron vertices we show that superstring amplitudes on the disc involving both open and closed strings should obey BCFW recursion relations. As a particular example, we analyze explicitly the case of 1→1 scattering of level one closed string states off a D-brane. Finally, we investigate whether the eikonal Regge regime conjecture holds in the presence of D-branes. 相似文献
75.
Linear stochastic programming provides a flexible toolbox for analyzing real-life decision situations, but it can become computationally
cumbersome when recourse decisions are involved. The latter are usually modeled as decision rules, i.e., functions of the
uncertain problem data. It has recently been argued that stochastic programs can quite generally be made tractable by restricting
the space of decision rules to those that exhibit a linear data dependence. In this paper, we propose an efficient method
to estimate the approximation error introduced by this rather drastic means of complexity reduction: we apply the linear decision
rule restriction not only to the primal but also to a dual version of the stochastic program. By employing techniques that
are commonly used in modern robust optimization, we show that both arising approximate problems are equivalent to tractable
linear or semidefinite programs of moderate sizes. The gap between their optimal values estimates the loss of optimality incurred
by the linear decision rule approximation. Our method remains applicable if the stochastic program has random recourse and
multiple decision stages. It also extends to cases involving ambiguous probability distributions. 相似文献
76.
Bert Jüttler Ulrich Langer Angelos Mantzaflaris Stephen E. Moore Walter Zulehner 《PAMM》2014,14(1):961-962
Isogeometric analysis (IGA) is a recently developed simulation method that allows integration of finite element analysis (FEA) with conventional computer-aided design (CAD) software [1,3]. This goal requires new software design strategies, in order to enable the use of CAD data in the analysis pipeline. To this end, we have initiated G + SMO (Geometry+Simulation Modules), an open-source, C++ library for IGA. G + SMO is an object-oriented, template library, that implements a generic concept for IGA, based on abstract classes for discretization basis, geometry map, assembler, solver and so on. It makes use of object polymorphism and inheritance techniques to provide a common framework for IGA, for a variety of different basis-types which are available. A highlight of our design is the dimension independent code, realized by means of template meta-programming. Some of the features already available include computing with B-spline, Bernstein, NURBS bases, as well as hierarchical and truncated hierarchical bases of arbitrary polynomial order. These basis functions are used in continuous and discontinuous Galerkin approximation of PDEs over (non-)conforming multi-patch computational (physical) domains. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
77.
We generalize a smoothing algorithm for finite min–max to finite min–max–min problems. We apply a smoothing technique twice,
once to eliminate the inner min operator and once to eliminate the max operator. In mini–max problems, where only the max
operator is eliminated, the approximation function is decreasing with respect to the smoothing parameter. Such a property
is convenient to establish algorithm convergence, but it does not hold when both operators are eliminated. To maintain the
desired property, an additional term is added to the approximation. We establish convergence of a steepest descent algorithm
and provide a numerical example. 相似文献
78.
The parameters of nuclear hyperfine splittings for the paramagnet Fe(dtc)2Br have been determined by Mössbauer measurements on a mixed system of this compound with the homologous ferromagnetic chloro derivative acting as host. The crystal field z axis is found to be perpendicular to the exchange field for Fe(dtc)2Br, in contrast to the host. 相似文献
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