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231.
232.
Gloria Dion Anne Harvey Carol Jackson Patricia Klag Jinghua Liu Craig Wright 《School science and mathematics》2001,101(8):427-438
This survey investigated the current status of calculator use in classrooms and schools. The results indicated that the prevailing policy in the sample of high schools is to allow the use of calculators during classroom learning activities and tests. Scientific calculators are more frequently used than graphing calculators in algebra I and geometry; whereas, graphing calculators are more frequently used in algebra II and precalculus/trigonometry. At the time of this survey, school policies regarding the use of graphing calculators with symbolic algebra capabilities were still not determined. 相似文献
233.
Imaginary powers of Laplace operators 总被引:1,自引:0,他引:1
We show that if is a second-order uniformly elliptic operator in divergence form on , then . We also prove that the upper bounds remain true for any operator with the finite speed propagation property.
234.
Otis C. Wright III 《Studies in Applied Mathematics》2020,144(3):327-356
A simple formula is proven for an upper bound for amplitudes of hyperelliptic (finite-gap or N-phase) solutions of the derivative nonlinear Schrödinger equation. The upper bound is sharp, viz, it is attained for some initial conditions. The method used to prove the upper bound is the same method, with necessary modifications, used to prove the corresponding bound for solutions of the focusing NLS equation (Wright OC, III. Sharp upper bound for amplitudes of hyperelliptic solutions of the focusing nonlinear Schrödinger equation. Nonlinearity. 2019;32:1929-1966). 相似文献
235.
236.
The effects of density on the Fermi resonance interaction in CO2 up to 534 amagat density was investigated. The Raman intensity of the polarized, anisotropic, and isotropic components of the 2ν2 and ν1 bands was determined as a function of the fluid density. By using the theory of Fermi resonance coupling the ratio of the unperturbed Raman polarizability matrix elements of the 2ν2 and ν1 bands was determined as a function of the fluid density. Changes in the vibrational anharmonicity, and an increasing repulsion of the vibration levels were found to decrease the effectiveness of the resonance interaction as the fluid density was increased, therefore altering the Raman intensity and frequency with changing density. 相似文献
237.
Nick Wright 《Journal of Functional Analysis》2005,220(2):265-303
The C0 coarse structure on a metric space is a refinement of the bounded structure and is closely related to the topology of the space. In this paper we will prove the C0 version of the coarse Baum–Connes conjecture and show that K*(C*X0) is a topological invariant for a broad class of metric spaces. Using this result we construct a ‘geometric’ obstruction group to the coarse Baum–Connes conjecture for the bounded coarse structure. We then show under the assumption of finite asymptotic dimension that the obstructions vanish, and hence we obtain a new proof of the coarse Baum–Connes conjecture in this context. 相似文献
238.
Pinna reflections as cues for localization 总被引:1,自引:0,他引:1
239.
J. Douglas Wright 《Journal of Dynamics and Differential Equations》2009,21(2):315-328
We prove that if a reaction-diffusion equation (in one space dimension) has asymptotically stable, exponentially localized
traveling wave solutions then there are solutions of the system which are nearly the linear superposition of two such pulses
moving in opposite directions away from one another. Moreover, such solutions are themselves asymptotically stable. This result
is meant to complement analytic or numeric studies into interactions of such pulses over finite times which might result in
the scenario treated here. Since the pulses are moving in opposite directions, it is not possible to put the problem into
a moving reference frame which renders the linear problem autonomous. We overcome this difficulty by embedding the original
system in a larger one wherein the linear part can be written as a time independent piece plus another piece which, even though
it is non-autonomous and large, has certain properties which allow us to treat it as if it were a small perturbation. 相似文献
240.
Jin-Song Pei François Gay-Balmaz Joseph P. Wright Michael D. Todd Sami F. Masri 《Nonlinear dynamics》2017,88(4):2435-2455
We call attention to a dual-pair concept for modeling hysteresis involving instantaneous switching: Specifically, there are two input–output pairs for each hysteresis model under one specific input, namely a differential pair and an integral pair. Currently in engineering mechanics, only one pair is being recognized and utilized, not the other. Whereas this dual-pair concept is inherent in the differential and algebraic forms of memristors and memcapacitors, the concept has not been carried over to memristive system theory, nor to memcapacitive system theory. We show that the “zero-crossing” feature in memristors, memcapacitors, and memristive/memcapacitive models (i.e., the “mem-models”) is also a feature of the differential pairs of well-known non-mem-models, examples of which are Ramberg–Osgood, Bouc–Wen, bilinear hysteresis, and classical Preisach. The dual-pair concept thus connects mem-models and non-mem-models, thereby facilitating the modeling of hysteresis, and raising a set of scientific questions for further studies that might not otherwise come to awareness. 相似文献