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排序方式: 共有121条查询结果,搜索用时 0 毫秒
41.
M. Dülk ST. Fischer M. Bitter M. Caraccia W. Vogt E. Gini H. Melchior W. Hunziker A. Buxens H.N. Poulsen A.T. Clausen 《Optical and Quantum Electronics》2001,33(7-10):899-906
A monolithically integrated and fully packaged Mach–Zehnder interferometer with semiconductor optical amplifiers (MZI-SOA) is demonstrated as polarisation-independent high-speed demultiplexer for up to 160 Gbit/s optical time division multiplexed (OTDM) data streams. 相似文献
42.
43.
Martin Bitter Sven Scharnowski Rainer Hain Christian J. Kähler 《Experiments in fluids》2011,50(4):1019-1030
High-repetition-rate PIV measurements were performed in the trisonic wind tunnel facility at the Bundeswehr University Munich
in order to investigate the boundary layer parameters on a generic rocket model and the recirculation area in the wake of
the model at Mach numbers up to Mach = 2.6. The data are required for the validation of unsteady flow simulations. Because
of the limited run time of the blow-down wind tunnel, a high-repetition-rate PIV system was applied to obtain the flow statistics
with high accuracy. The results demonstrate this method’s potential to resolve small-scale flow phenomena over a wide field
of view in a large Mach number range but also show its limitations for the investigations of wall-bounded flows. 相似文献
44.
Ildikó Mohammed-Ziegler Áron Szöllősy Miklós Kubinyi András Grofcsik Alajos Grün István Bitter 《Supramolecular chemistry》2013,25(6):415-421
Complexation of lithium ions by three chromoionophoric calix[4]arenes has been studied by 1H and 7Li NMR spectroscopy. The signalling unit of the chromoionophores is the N-methylpyridinium(methyleneimino) group in conjugation with a phenolic group of the calixarene ring while the coordination spheres contain esteric (ethoxycarbonylmethoxy) or etheric (ethoxy, propoxy) units. 1H NMR and NOESY measurements suggest the dominance of cone conformations of the calixarene rings with slight, solvent-dependent distortions. Complexation occurs only in the presence of a weak base. The interaction with lithium ions causes a broadening of both the 1H and 7Li NMR signals. Analysis of the chemical shifts in the three complexes indicates a different coordination environment for the lithium with the calixarene containing esteric groups from those having etheric groups. This explains the differences in the stabilities of the lithium complexes of the two types of calixarenes. 相似文献
45.
The Mitsunobu cyclization of p-t-butylthiacalix[4]arene with glycols was expanded to oligoethylene glycol analogues composed of O, S and N atoms in the chain. In this way a number of 1,3-thiacalix[4]monocrowns have been synthesized, offering simple and general access to a large variety of crowned thiacalixarenes. The binding properties of some ligands towards transition metal cations have been studied by 1H NMR, UV/Vis spectroscopic and potentiometric methods. 相似文献
46.
47.
Róbert Bereczki Béla Ágai István Bitter 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(1-2):53-58
A series of mono and bis(benzo-15-crown-5 and 18-crown-6)ethers comprisingterminal alkenyl functions were synthesized andtheir alkali cation complexingabilities were evaluated by picrate extractionmethod. These ionophores providethe possibility of binding covalently to polymer matrices. 相似文献
48.
49.
Sándor Kunsági-Máté Giuseppe Vasapollo Kornélia Szabó István Bitter Giuseppe Mele Luigia Longo László Kollár 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):71-78
The molecular encapsulation of functionalized fullerenes (substituted fulleropyrrolidines) with water-soluble calixarenes
was studied by photoluminescence and quantum-chemical methods. The results show that both the thiacalix[4]arene-tetrasulfonate
and calix[6]arene-hexasulfonate are able to overcome the natural water-repulsive character of fullerenes. However, the functionalization
of calixarenes and fullerenes induces significant changes in the molecular encapsulation processes, and the obtained thermodynamic
behavior of the complex formation highlights the importance of the entropy. Our results can contribute to the development
of the synthesis and design of functionalized calixarenes supporting their application in pharmaceutical and food chemistry. 相似文献
50.
Baldé CP Leynaud O Barnes P Peláez-Jiménez E de Jong KP Bitter JH 《Chemical communications (Cambridge, England)》2011,47(7):2143-2145
Hydrogen storage properties of Ti-doped nanosized (~20 nm) NaAlH(4) supported on carbon nanofibers were affected by the stage at which Ti was introduced. When Ti was deposited first followed by NaAlH(4), sorption properties were superior to the case where NaAlH(4) was deposited first followed by NaAlH(4). This was the result of both a smaller NaAlH(4) particle size and the more extensive catalytic action of Ti in the former material. 相似文献