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991.
Andrei N. Yakunin 《Central European Journal of Physics》2004,2(3):535-555
A cubic structure of polymer colloid complexes is studied. The technique of the research includes i) an analysis of well-known
literature SAXS data; on this basis, ii) constructing a simple model to estimate geometric structure parameters and to obtain
a simulated scattering curve; and iii) comparing the model with the real structure obtained from the SAXS data, using the
reconstruction of electron density distribution. A bicontinuous structure in cubic mesophases is formed.
Dedicated to the memory of Alexander T. Dembo 相似文献
992.
Victor P. Palamodov 《Arkiv f?r Matematik》2004,42(1):119-152
A fundamental solution of the acoustical equation with a variable refraction coefficient is constructed. The solution satisfies
the limiting absorption and radiation conditions. The optimal high frequency estimate is proved for square means of the solution.
The source function for the diffusion equation is a by-product of this construction.
Partially supported by a stipend of the Mathematical Scientific Research Institute at Berkeley, 2001. 相似文献
993.
994.
G. Sreenivasulu Reddy J. Hanumanthachari T. Vasanthi 《Southeast Asian Bulletin of Mathematics》2003,26(2):331-335
This paper is mainly dealt with the structure of totally ordered rings (t.o. rings) whose positive cones are finitely generated as multiplicative right ideals.AMS Subject Classification (1991): 16W80, 13J25 相似文献
995.
We consider a discretized volume V consisting of finite, congruent and attached copies of a tile t. We find a group L
V
the orbit of which, when applied to t, is just V. We show the connection between the structural matrixQ in the formal solution of a boundary value problem formulated for volume V and the so called auxiliary matrix of the graph Γ
v
associated with V. We show boundary value problems to be isomorphic if the graphs associated with the volumes are isomorphic, or, if the covering
groups are Sunada pairs. 相似文献
996.
Sam Efromovich 《Annals of the Institute of Statistical Mathematics》2004,56(2):205-223
A blockwise shrinkage is a popular procedure of adaptation that has allowed the statisticians to establish an impressive bouquet
of asymptotic mathematical results and develop softwares for solving practical problems. Traditionally risks of the estimates
are studied via upper bounds that imply sufficient conditions for a blockwise shrinkage procedure to be minimax. This article
suggests to analyze the estimates via exact (non-asymptotic) lower bounds established for a no-signal setting. The approach
complements the familiar minimax, Bayesian and numerical analysis, it allows to find necessary conditions for a procedure
to attain desired rates, and it sheds a new light on popular choices of blocks and thresholds recommended in the literature.
Mathematical results are complemented by a numerical study.
Supported in part by NSF Grants DMS-9971051 and DMS-0243606. 相似文献
997.
998.
G. Martínez J. Milln J. Contreras 《Journal of polymer science. Part A, Polymer chemistry》2003,41(4):508-519
A poly(vinyl chloride) (PVC) sample was chlorinated in solution in the presence of 2,2′‐azobisisobutyronitrile and by the fluid‐bed method. The aim was to evaluate the scope of the stereoselectivity of the chlorination reaction. The quantitative microstructural analysis of the residual PVC with a degree of chlorination was followed by 13C NMR spectroscopy. From the evolution of the content of isotactic (mm), heterotactic (mr), and syndiotactic (rr) triads and of mmmm, mmmr, and rmmr isotactic pentads in the unchlorinated parts of the polymer, it was unambiguously inferred that the chlorination reaction proceeds by a stereoselective mechanism in that the mr heterotactic triads are the most reactive structures followed by the isotactic triad at mmmr and rmmr pentads. This conclusion was confirmed on the basis of the Fourier transform infrared results. The results provide valuable information regarding the effect of tacticity and related local conformations in the chemical reactions of PVC. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 508–519, 2003 相似文献
999.
András Sütő 《Journal of statistical physics》2003,112(1-2):375-396
We study condensation of trapped bosons in the limit when the number of particles tends to infinity. For the noninteracting gas we prove that there is no phase transition in any dimension, but in any dimension, at any temperature the system is 100% condensated into the one-particle ground state. In the case of an interacting gas we show that for a family of suitably scaled pair interactions, the Gross–Pitaevskii scaling included, a less-than-100% condensation into a single-particle eigenstate, which may depend on the interaction strength, persists at all temperatures. 相似文献
1000.
Ruth Kellerhals 《Israel Journal of Mathematics》2004,143(1):361-379
Forn≥2, we quantify the Margulis constant ε(n) giving rise to a thick and thin decomposition of hyperbolicn-manifolds of finite volume. As a consequence, we obtain new universal lower bounds for the volume and Gromov's invariant
as well as a geometrical inequality between injectivity radius and diameter for compact manifolds. Finally, we concretise
the upper bound for the counting function of hyperbolic manifolds of dimension >4 as described by Burger, Gelander, Lubotzky
and Mozes.
Partially supported by Schweizerischer Nationalfonds No. 20-61379.00 and 20-67619.02. 相似文献