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991.
Abstract. T. Kato [9] found an important property of semi-Fredholm pencils,
now called the Kato decomposition. Few years later, M.A. Kaashoek [7]
introduced operators having the property
as a generalization of semi-Fredholm operators. In [4], it is proved that these two notions are linked. The
aim of this work is to study the stability of the property
under finite perturbation. 相似文献
992.
Mestas JL Lenz P Cathignol D 《The Journal of the Acoustical Society of America》2003,113(3):1426-1430
Stable cavitation is produced on the surface of a special target, i.e., an abrasive foil with a grain size of about 15 microm, insonified by a 473 kHz focused beam. Cavitation bubbles are first created by a pressure of about 2 MPa. Progressive reduction of the pressure to about 100 kPa leads to a state of stable cavitation characterized by strong stable emission of the half-order subharmonic. This state can be maintained for five hours if the defining parameters (position and pressure) are optimized and constant to within a few percent. There is strong evidence for the presence of "latent" cavitation bubbles, which can persist for a few minutes without being excited. 相似文献
993.
994.
Niklas?Darin Norman?Kadhom Jean-Jacques?Brière Dominique?Chretien Cécile?M?Bébéar Agnès?R?tig Arnold?Munnich Pierre?RustinEmail author 《BMC biochemistry》2003,4(1):15
Background
Mycoplasma contaminations are a recurrent problem in the use of cultured cells, including human cells, especially as it has been shown to impede cell cycle, triggering cell death under various conditions. More specific consequences on cell metabolism are poorly known. 相似文献995.
The enantioselective synthesis of a potent Maxi-K potassium channel opener (BMS-204352) mediated by N-fluoroammonium salts of cinchona alkaloids is described. Two synthetic pathways were evaluated. An ee as high as 88% was achieved (>99% after a single recrystallisation). 相似文献
996.
Dissimilar material joining using laser (aluminum to steel using zinc-based filler wire) 总被引:9,自引:0,他引:9
Alexandre Mathieu Rajashekar Shabadi Alexis Deschamps Michel Suery Simone Matteï Dominique Grevey Eugen Cicala 《Optics & Laser Technology》2007,39(3):652-661
Joining steel with aluminum involving the fusion of one or both materials is possible by laser beam welding technique. This paper describes a method, called laser braze welding, which is a suitable process to realize this structure. The main problem with thermal joining of steel/aluminum assembly with processes such as TIG or MIG is the formation of fragile intermetallic phases, which are detrimental to the mechanical performances of such joints. Braze welding permits a localized fusion of the materials resulting in a limitation on the growth of fragile phases. This article presents the results of a statistical approach for an overlap assembly configuration using a filler wire composed of 85% Zn and 15% Al. Tensile tests carried on these assemblies demonstrate a good performance of the joints. The fracture mechanisms of the joints are analyzed by a detailed characterization of the seams. 相似文献
997.
This paper is a continuation of “Diffusions conditionelles, I.” If (xt, zt) is a two-component diffusion process, it is shown that under appropriate conditions, the process xt (t ? T), given (zs, s ? T) is a nonhomogeneous strong Markov process, whose generator is explicitly found by using the theory of stochastic flows. The filtering equation is reduced to an ordinary partial differential equation. 相似文献
998.
999.
1000.
Catherine Verchre Dominique Rousselle Claude Viel 《Magnetic resonance in chemistry : MRC》1978,11(8):395-397
Carbon-13 NMR spectra of some dihydro- and tetrahydro-isoquinolines were studied and applied to the assignments of 13C NMR signals of some 8,13-diazasteroids related to the estrone series. Some deuterated compounds were also examined. All signals could be assigned and an important long-range isotopic effect was observed which seems to be due to an interaction between the C? H(D) bond and the nitrogen lone pairs. 相似文献