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The mathematical intelligencer encourages comments about the material in this issue. letters to the editor should be sent
to either of the editors-in-chief, chandler davis or Marjorie Senechal. 相似文献
103.
Lecomte S Paschotta R Pawlik S Schmidt B Furusawa K Malinowski A Richardson DJ Keller U 《Optics letters》2005,30(3):290-292
We present a singly resonant, synchronously pumped optical parametric oscillator with a record-high repetition rate of 39 GHz. The transform-limited 2.2-ps pulses at 1570 nm have as much as 2.1-W average output power. The all-solid-state pump source is based on a diode-pumped passively mode-locked 39-GHz Nd:YVO4 laser and an efficient ytterbium-doped fiber amplifier. 相似文献
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We prove exponential decay for derivatives of covariance operators on the lattice. This result is obtained by using random walk methods on the v-dimensional lattice and a certain estimate on the generating function of the one-dimensional random walk. The result is useful in the frame of the cluster and mean field expansion of continuous spin models on the lattice. 相似文献
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Dr. Tobias Böttcher Simon Steinhauer Dr. Lesley C. Lewis‐Alleyne Beate Neumann Dr. Hans‐Georg Stammler Dr. Bassem S. Bassil Prof. Dr. Gerd‐Volker Röschenthaler Prof. Dr. Berthold Hoge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):893-899
The addition of BCl3 to the carbene‐transfer reagent NHC→SiCl4 (NHC=1,3‐dimethylimidazolidin‐2‐ylidene) gave the tetra‐ and pentacoordinate trichlorosilicon(IV) cations [(NHC)SiCl3]+ and [(NHC)2SiCl3]+ with tetrachloroborate as counterion. This is in contrast to previous reactions, in which NHC→SiCl4 served as a transfer reagent for the NHC ligand. The addition of BF3 ? OEt2, on the other hand, gave NHC→BF3 as the product of NHC transfer. In addition, the highly Lewis acidic bis(pentafluoroethyl)silane (C2F5)2SiCl2 was treated with NHC→SiCl4. In acetonitrile, the cationic silicon(IV) complexes [(NHC)SiCl3]+ and [(NHC)2SiCl3]+ were detected with [(C2F5)SiCl3]? as counterion. A similar result was already reported for the reaction of NHC→SiCl4 with (C2F5)2SiH2, which gave [(NHC)2SiCl2H][(C2F5)SiCl3]. If the reaction medium was changed to dichloromethane, the products of carbene transfer, NHC→Si(C2F5)2Cl2 and NHC→Si(C2F5)2ClH, respectively, were obtained instead. The formation of the latter species is a result of chloride/hydride metathesis. These compounds may serve as valuable precursors for electron‐poor silylenes. Furthermore, the reactivity of NHC→SiCl4 towards phosphines is discussed. The carbene complex NHC→PCl3 shows similar reactivity to NHC→SiCl4, and may even serve as a carbene‐transfer reagent as well. 相似文献