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171.
Acousto-optic (AO) imaging is a promising technique that is able to reveal optical properties in the millimeter range inside scattering media by tagging the photon paths with an ultrasonic beam. To increase both the contrast and the resolution of the AO images, we have explored the possibility of using the nonlinear response of the speckle modulation. Variation of the second-harmonic signal as the square of the ultrasonic amplitude has been found, and strong reduction of the tagged zone size has been demonstrated. 相似文献
172.
We build an irreducible unitary representation of SO( ) from the usual one of SO( n ) in the space of harmonic homogeneous polynomials of degree m of
n
. We give a characterization of these new representations which extends in a natural way the finite dimensional characterization. In the particular case of SO( ), we thus get some results of Olshanskii (cf. [12]). This leads to a new proof of McKean conjecture about irreducible representations of ( infin ) (cf. [10]). 相似文献
173.
Claude LeBrun 《Mathematische Annalen》1991,289(1):383-392
Work supported in part by NSF Grant #DMS-8704401 相似文献
174.
175.
The tetxaacetylation of isobutene has been perfomed in AlCl3/AcCl. Treatment of the crude reaction medium with liquid ammonia yields the title compound. 相似文献
176.
Claude Brezinski 《Journal of Computational and Applied Mathematics》1983,9(4):369-376
The recursive projection algorithm derived in a previous paper is related to several well-known methods of numerical analysis such as the conjugate gradient method, Rosen's method and Henrici's. It is connected with the general interpolation problem, with extrapolation methods, with orthogonal projection on a subspace and with Fourier expansions. Several other connections and applications are presented. 相似文献
177.
The 13C NMR chemical shifts have been measured for dilute aqueous solutions of acetonitrile in presence of various electrolytes including silver nitrate. The two formation constants of the silver ion/acetonitrile complexes have been calculated assuming an additive contribution of each possible complex configuration. Under these conditions the values obtained for the formation constants are very close to those deduced from vapour pressure or electromotive force techniques. The other systems studied are discussed in relation to the salting phenomenon in aqueous electrolyte solutions. 相似文献
178.
The authors have treated a statistical model which describes time intervals distribution between successive echos scattered by a fluctuating surface. A sonar signal scattered by sea surface is taken as a practical example. It is shown that scattered echos are achieved by random deleting of transmitted signals. 相似文献
179.
Claude Brezinski 《Applied Numerical Mathematics》1985,1(6):457-462
Convergence acceleration methods consist in the construction of a sequence converging faster than the initial sequence. Each member of the new sequence is a guess for the limit and it is computed from a restricted number of terms of the initial sequence. It is shown herein how convergence acceleration methods can be used to predict the next (unknown) term of the initial sequence instead of its limit. Particular emphasis on Aitken's △2 process and the E-algorithm is placed. 相似文献
180.