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941.
Fayon F Le Saout G Emsley L Massiot D 《Chemical communications (Cambridge, England)》2002,(16):1702-1703
2D 31P refocused INADEQUATE NMR experiments have been used to determine through-bond P-O-P connectivities in crystalline and disordered phosphates. 相似文献
942.
Dominique Barbolosi 《Monatshefte für Mathematik》1999,28(4):189-200
For any irrational , let denote the regular continued fraction expansion of x and define f, for all z > 0 by and by J. GALAMBOS proved that (μ the Gauss measure)
In this paper, we first point out that for all , ( has no limit for for almost all , proving more precisely that: For all , one has for almost all
相似文献
943.
The wetting of Pb-Ni crystals on graphite has been observed at 558 K in a Scanning Auger Microprobe. Samples were prepared so as to produce 10 m crystals of Pb with Ni contents increasing from 0 to 0.3 wt% along one axis of the graphite substrate. In the low Ni region, the contact angle was found to decrease slowly from 119° to 98° with increasing Ni content. In the region of high Ni content, a constant contact angle of 83° was measured. In between, crystals with contact angles of 98° and 83° were observed to coexist, near the limit of solubility of Ni in Pb, indicating the presence of a first order transition in contact angle. The continuous decrease in contact angle, in the low Ni region, is due to Ni adsorption at the Pb-graphite interface, which leads to a decrease in interfacial energy. The constant contact angle in the high Ni region is associated with the precipitation of a Ni-rich phase. Various hypotheses are advanced to account for the first order transition in contact angle as a function of Ni concentration. 相似文献
944.
945.
Heuzé K Méry D Gauss D Blais JC Astruc D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(16):3936-3944
A series of bis(tert-butylphosphine)- and bis(cyclohexylphosphine)-functionalized Pd(II) monomers and polyamino (DAB) dendritic catalysts were synthesized and investigated for Sonogashira carbon-carbon coupling reactions in a copper-free procedure. The influence of phosphine substituents (tBu versus Cy) on the reaction kinetics was investigated by a GPC technique to monitor the reactions. The dendritic catalysts containing the cyclohexylphosphine ligands could be recovered and reused without loss of efficiency until the fifth cycle. The dendritic Pd(II) catalysts show a negative dendritic effect, that is, the catalyst efficiency decreases as the dendrimer generation increases. 相似文献
946.
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
947.
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
948.
949.
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950.
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