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91.
92.
The operation of an eightfold longitudinally diode laser pumped 1.06m cw Nd:YAG slab laser is demonstrated. The 809 nm diode radiation is focused through a dichroic coating into each laser channel starting from the reflection points of the 1.06m beam in the slab crystal. At an absorbed pump power in the crystal of 2830 mW a maximum cw TEM00 output of 1075 mW was achieved with a corresponding slope efficiency of 42.5%. 相似文献
93.
According to their spectroscopic behavior, four classes of nonafulvenes may be distinguished, but, so far, only three classes have been identified. Type-A nonafulvenes (including parent 1a ) are typically olefinic molecules with strongly alternating bond lengths and a nonplanar nine-membered ring. Type-B nonafulvenes are characterized by four pairs of equivalent ring H-atoms and ring C-atoms. Spectra of both Type-A and Type-B nonafulvenes are not dependent on temperature and solvent polarity. However, spectra of Type-C nonafulvenes (including prototype 1d with R1 = R2 = NMe2) are strongly influenced by temperature and solvent polarity due to an equilibrium 1?1 ± between the nonpolar olefinic 1 and dipolar planarized 1 ±. So far, Type-D nonafulvenes occurring exclusively in the dipolar form 1 ± were unknown. Synthetic attempts towards nonafulvenes of Type D are described and problems encountered in nonafulvene syntheses are discussed. Several new cyclononatetraenes and four new nonafulvenes (or nonafulvalenes) 31, 1n, 3 , and 5 have been synthesized. Spectroscopic evidence shows that 11,12-bis(diethylamino)nonatriafulvalene 5 is the first Type-D nonafulvene. 相似文献
94.
Michael?Lisurek Bernd?Rupp J?rg?Wichard Martin?Neuenschwander Jens?Peter?von?Kries Ronald?Frank J?rg?Rademann Ronald?Kühne 《Molecular diversity》2010,14(2):401-408
Success in small molecule screening relies heavily on the preselection of compounds. Here, we present a strategy for the enrichment
of chemical libraries with potentially bioactive compounds integrating the collected knowledge of medicinal chemistry. Employing
a genetic algorithm, substructures typically occurring in bioactive compounds were identified using the World Drug Index.
Availability of compounds containing the selected substructures was analysed in vendor libraries, and the substructure-specific
sublibraries were assembled. Compounds containing reactive, undesired functional groups were omitted. Using a diversity filter
for both physico-chemical properties and the substructure composition, the compounds of all the sublibraries were ranked.
Accordingly, a screening collection of 16,671 compounds was selected. Diversity and chemical space coverage of the collection
indicate that it is highly diverse and well-placed in the chemical space spanned by bioactive compounds. Furthermore, secondary
assay-validated hits presented in this study show the practical relevance of our library design strategy. 相似文献
95.
D. Neuenschwander 《Journal of Mathematical Sciences》2001,106(1):2725-2731
96.
D. Neuenschwander 《Journal of Mathematical Sciences》1997,84(3):1138-1144
Carrying over a result of Kuelbs and Ledoux, we show that in generalized convolution algebras as introduced by Urbanik, domains
of attraction of stable measures go over, after suitable truncation and renormalization, into domains of attraction of the
characteristic measure of the convolution algebra. For convolutions which are induced by a (deterministic) semigroup operation,
only the “large” terms are responsible for convergence to the stable law.
Proceedings of the XVII Seminar on Stability Problems for Stochastic Models, Kazan, Russia, 1995, Part III 相似文献
97.
98.
99.
Sergei M. Pimenov Andrey A. Khomich Igor I. Vlasov Evgeny V. Zavedeev Alexander V. Khomich Beat Neuenschwander Beat Jäggi Valerio Romano 《Applied Physics A: Materials Science & Processing》2014,116(2):545-554
In this paper, we report on the bulk modifications of type IIa single-crystal diamond with visible 10-ps pulses (at λ = 532 nm) and microstructural changes characterized by the appearance of several ‘unidentifiable’ vibrational modes in the frequency range of 1000–1400 cm?1 in the Raman spectra of laser-modified diamond. It is found that the new Raman modes are strongly pronounced in the spectra of high-stress regions in immediate proximity to the bulk microstructures in the absence of the G mode at ~1580 cm?1 characteristic of the sp2 phase. The high internal stresses are determined from the splitting of the triply degenerate diamond Raman line. The revealed structure transformation is localized within a narrow bulk layer near the bulk microstructures formed, and the stress relaxation is found to result in disappearance of the detected vibrational modes in the spectra. It is suggested that the formation of bulk regions with a sp3 carbon structure consisting of Z-carbon and hexagonal diamond is responsible for the appearance of new Raman modes in the spectra of laser-modified diamond. These findings evidence that the stress-assisted formation of novel metastable carbon phases or defect structures occur in the course of bulk modification of diamond with ps-laser pulses. In addition, we report the results of simulations of internal stresses in the system ‘graphitized cylinder-in-diamond’ to show (1) the effect of the mechanical properties of laser-modified diamond on the resulting stresses and (2) formation of bulk microscopic regions with high stresses of >10 GPa, i.e., the conditions at which various sp3 carbon allotropes and defect structures become more stable than graphite. 相似文献
100.