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A modified commercial mass spectrometer was used to perform quantitative measurements on negative ions of selected organic compounds at about 10?4 Torr source pressure. The pressure dependency of the molecular ion intensity on pure compounds and binary mixtures shows up two different sources of slow secondary electrons. At low total source pressures a log-log plot of the ion intensity against the sample amount is linear and slow electrons are produced predominantly by wall effects, whereas at high pressures plasma effects arise with a non-linear pressure dependency. 相似文献
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Diether G. Markees 《Helvetica chimica acta》1973,56(4):1382-1384
2-Methoxymethyl naphthalene ( 1 ) was synthesized and its properties were found to be different from those reported in the literature. The reaction of this compound with cold conc. nitric acid gave 8-nitro-2-naphthaldehyde ( 2 ). When 1-methoxymethyl naphthalene ( 4 ) was treated similarly 4-nitro-1-methoxymethyl naphthalene ( 5 ) and 8-nitro-1-naphthaldehyde ( 6 ) were obtained. 相似文献
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Michael Diether 《Statistical Inference for Stochastic Processes》2012,15(3):257-284
We consider a time-inhomogeneous diffusion process, whose drift term contains a deterministic T-periodic signal with known periodicity. This signal is supposed to be contained in a Besov space, we try to estimate it using a non-parametric wavelet estimator. Our estimator is inspired by the thresholded wavelet density estimator constructed by Donoho, Johnstone, Kerkyacharian and Picard in 1996. Under certain ergodicity assumptions to the process, we can give the same asymptotic rate of convergence as for the density estimator. 相似文献
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Drahonovský D Knof U Jungo L Belser T Neels A Labat GC Stoeckli-Evans H von Zelewsky A 《Dalton transactions (Cambridge, England : 2003)》2006,(11):1444-1454
A C2-symmetric enantiopure 4,5-bis(pinene)-2,2'-bipyridine ligand (-)-L was used to investigate the diastereoselectivity in the formation of [ML3]2+ coordination species (M = Fe(II), Ru(II), Os(II), Zn(II), Cd(II), Cu(II), Ni(II)), and [ML2Cl2] (M = Ru(II), Os(II)). The X-ray structures of the [ML3]2+ complexes were determined for Delta-[FeL3](PF6)2, Delta-[RuL3](PF6)2, Lambda-[RuL3](PF6)2, Delta-[OsL3](PF6)2, and Lambda-[OsL3](TfO)2. All of these compounds were also characterized by NMR, CD and UV/VIS absorption spectroscopy. The [FeL3]2+ diastereoisomers were studied in equilibrated solutions at various temperatures and in several solvents. The [RuL3]2+ complexes, which are thermally stable up to 200 degrees C, were photochemically equilibrated. 相似文献
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H. J. Eichler H. Fery J. Knof J. Eichler 《Zeitschrift für Physik B Condensed Matter》1977,28(4):297-306
Third-order nonlinear optical susceptibilities of different crystals have been measured relative to LiNbO3 by observing collinear phase-matched difference frequency generation
1=2
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4. The two incident light waves have been produced by a ruby laser (
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2=694.3 nm) and by induced Raman scattering (
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4=765.8 nm). With noncollinear phase-matching the number of nonlinear processes and the possibilities to determine nonlinear coefficients is much larger than in the collinear case. Therefore the theory of Raman-type third order interactions has been extended to noncollinear propagation of the interacting waves. The theory has been tested experimentally for CdS. 相似文献