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Reaction of Metal and Metalloid Compounds with Polyfunctional Molecules. XIX. Synthesis of Amidoborazines By reaction of 2-chloro-1,3,4,5,6-pentamethylborazin with silylated carbonic acid amides and thioamides resp. the corresponding amidoborazines are obtained. By reaction of lithiated hexamethyldisilazane with 2-chloro-1,3,4,5,6-pentamethylborazine, the 2-hexamethyldisilazanyl-1,3,4,5,6-pentamethylborazine is formed. 1H, 11B, and 19F n.m.r. spectra, mass spectra and characteristic i.r. group frequencies are reported. 相似文献
3.
A simple semiconductor gas sensor (TGS 812) is used for the on-line measurement and control of indole during the production of l-tryptophan from indole and l-serine with immobilized E. coli cells. Indole is estimated in the reactor gas space. In combination with an automatic indole supply system, a feed-batch process became possible. The indole concentration was monitored and kept within the optimal range (300–600 mg l?1). A simple gas-sensing electrode dipped in the reaction medium provides direct measurement of organic solvents and gases in the liquid. Such a system is suitable for on-line determination of ethanol (10–70 g l?1) during continuous production of ethanol with immobilized yeast cells. 相似文献
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K. D. Kirchberg 《Journal of Geometry and Physics》1990,7(4):449-468
If M2m is a closed Kähler spin manifold of positive scalar curvature R, then each eigenvalue λ of type r (r {1, …, [(m + 1)/2]}) of the Dirac operator D satisfies the inequality λ2 ≥ rR0/4r − 2, where R0 is the minimum of R on M2m. Hence, if the complex dimension m is odd (even) we have the estimation for the first eigenvalue of D. In the paper is also considered the limiting case of the given inequalities. In the limiting case with m = 2r − 1 the manifold M2m must be Einstein. The manifolds S2, S2 × S2, S2 × T2, P3(
), F(
), P3(
) × T2 and F(
3) × T2, where F(
3) denotes the flag manifold and T2 the 2-dimensional flat torus, are examples for which the first eigenvalue of the Dirac operator realizes the limiting case of the corresponding inequality. In general, if M2m is an example of odd complex dimension m, then M2m × T2 is an example of even complex dimension m + 1. The limiting case is characterized by the fact that here appear eigenspinors of D2 which are Kählerian twistor-spinors. 相似文献
5.
André B?sel J?rg Ehlbeck Nicole K?nig Klaus-Dieter Salewski Jürgen R?pcke 《Optical Review》2012,19(5):332-336
For an enhanced tuning of an external-cavity Littrow diode laser at 670 nm a new approach based on the frequency controlling of intra-cavity acousto-optic modulators (AOM) has been developed and tested. Using a method called “mode shaking” a nearly continuously laser tuning over a frequency range of 186 GHz (0.279 nm) within a time interval of 20 ms has been achieved. A further method called “far laser frequency jump” allows frequency changes of up to 1080 GHz (1.6 nm) between two spectral regions of the diode laser emission range within about 50 μs. 相似文献
6.
We treat a simple generalization of the Jaynes-Cummings model to three-level atoms interacting with two harmonic oscillators. The model allows for classical chaos even in the rotating wave approximation, as was recently shown by Shepelyanski. Under conditions most favorable for classical chaos we find linear level repulsion à la Wigner. 相似文献
7.
Nikolaus Seiler Herbert Schneider und Klaus-Dieter Sonnenberg 《Fresenius' Journal of Analytical Chemistry》1970,252(2-3):127-136
Zusammenfassung Von etwa 80 1-Dimethylamino-naphthalin-5-sulfonyl-(DANS-)Derivaten biogener Amine und verwandter Verbindungen mit unterschiedlichen strukturellen Elementen wurden die durch Elektronenstoß induzierten Fragmentierungen untersucht. Die Prinzipien dieser Fragmentierungen und die Brauchbarkeit der Massenspektrometrie bei niedrigem Auflösungsvermögen für die Identifizierung dünnschicht-chromatographisch getrennter DANS-Derivate biogener Amine aus Gewebsextrakten werden diskutiert.
Mass spectrometric identification of biogenic amines as 1-dimethylamino-naphthalene-5-sulphonyl derivatives
The fragmentation by electron impact of approximately 80 1-dimethylamino-naphthalene-5-sulphonyl (DANS) derivatives of biogenic amines and related substances of different structural features has been studied. The principles of these fragmentations and the suitability of low resolution mass spectrometry for the identification of thin-layer chromatographically separated DANS-derivatives of biogenic amines from tissue extracts are discussed.相似文献
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