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101.
102.
Résumé Soit (V
)0 une résolvante définie sur un espace mesurable telle que le noyau initial est borné; on trouve une condition nécéssaire et suffisante pour qu'un noyau borné U possède une résolvante (U
)0 telle que U
V
pour tout 0. On donne plusieurs applications de ce résultat. 相似文献
103.
104.
105.
A clustering method has been developed to group signals that display similar dynamic behavior. The procedure involves using the method of time delay embedding to construct a trajectory in state space from a time series. Certain features that characterize the geometry of the trajectory have been defined. These features were subjected to a series of statistical tests to determine their usefulness in a hierarchical clustering analysis. The latter is aimed at finding groups of similar trajectories. The trajectory-based clustering algorithm has been applied to simulated data, which included both stochastic data generated by a linear AR model, and nonlinear data generated by a Duffing oscillator. The results show that the algorithm works reliably in both cases. 相似文献
106.
HuiGUO WuXinZOU QiJI JiBenMENG 《中国化学快报》2005,16(6):751-754
A series of photo active azido analogues have been synthesized and their photochromic properties have also been investigated by UV-Vis spectrum. It will be used for the rapid and reliable preparation of large amounts of stable, non-radioactive labeled DNA and RNA hybridization probes. And it is supposed to be easily detected for its photochromic properties. 相似文献
107.
ter Wiel MK van Delden RA Meetsma A Feringa BL 《Journal of the American Chemical Society》2005,127(41):14208-14222
To investigate the unidirectional rotation of chiral overcrowded biphenanthrylidenes in more detail, the size of the substituent next to the double bond responsible for the unidirectionality of rotation was varied. The thermal and photochemical isomerization of three sterically overcrowded alkenes is described. The behavior of the biphenanthrylidenes with methyl and ethyl substituents is rather similar, and these compounds undergo a unidirectional 360 degrees rotation around the central double bond in a four-step sequence involving two photochemical cis-trans isomerizations and two thermal helix inversions. The only difference between these two true molecular motors was a small entropic effect, which causes the ethyl substituted molecular motor to rotate slightly faster. The behavior of the i-propyl substituted compound differs significantly from that of the other two. Although not all different isomers of the i-propyl substituted molecular motor were detected spectroscopically, experimental data led to the conclusion that this compound can also be considered as a molecular motor and is capable of performing a 360 degrees unidirectional rotation. (1)H NMR and X-ray analysis show a meso-like form as an intermediate in the unidirectional rotation, which proves that the thermal helix inversion is a stepwise process. 相似文献
108.
James R. Gord Stevan R. Horning Joseph M. Wood R. Graham Cooks Ben S. Freiser 《Journal of the American Society for Mass Spectrometry》1993,4(2):145-151
We report studies of the internal energy deposited during activation of mass-selected ions through electron-ion collisions. Characteristic fragmentations of the molecular ion of limonene and W(CO) n/+ (n = 1–6) indicate that electron-induced dissociation in a Fourier transform ion cyclotron resonance mass spectrometer proceeds via multiple collisions and that the average internal energy deposited during the activation process can be selected to be similar to that associated with electron-impact ionization. Control of the degree of ion excitation through selection of the electron energy, flux, and interaction time with the ions of interest is demonstrated, and advantages of this promising activation technique are discussed. 相似文献
109.
The central chirality of simple amino alcohols was amplified by binding to a dynamically axially chiral biphenol receptor and expressed as supramolecular chirality by effecting a change from a nematic to a cholesteric liquid crystalline phase. 相似文献
110.