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121.
Salzmann I Heimel G Duhm S Oehzelt M Pingel P George BM Schnegg A Lips K Blum RP Vollmer A Koch N 《Physical review letters》2012,108(3):035502
Current models for molecular electrical doping of organic semiconductors are found to be at odds with other well-established concepts in that field, like polaron formation. Addressing these inconsistencies for prototypical systems, we present experimental and theoretical evidence for intermolecular hybridization of organic semiconductor and dopant frontier molecular orbitals. Common doping-related observations are attributed to this phenomenon, and controlling the degree of hybridization emerges as a strategy for overcoming the present limitations in the yield of doping-induced charge carriers. 相似文献
122.
J. A. Weima A. M. Zaitsev R. Job G. Kosaca F. Blum G. Grabosch W. R. Fahrner J. Knopp 《Journal of Solid State Electrochemistry》2000,4(8):425-434
Polycrystalline chemical vapor deposition (CVD) diamonds films grown on silicon substrates using the microwave-enhanced CVD
technique were polished using the thermochemical polishing method. The surface morphology of the samples was determined by
optical and scanning electron microscopes before and after polishing. The average surface roughness of the as-grown films
determined by the stylus profilometer yielded 25 μm on the growth side and about 7 μm on the substrate side. These figures
were almost uniform for all the samples investigated. Atom force microscopic measurements performed on the surface to determine
the average surface roughness showed that thermochemical polishing at temperatures between 700 °C and 900 °C reduced the roughness
to about 2.2 nm on both the substrate and growth sides of the films. Measurements done at intermittent stages of polishing
using confocal micro-Raman spectroscopy showed that thermochemical polishing is accompanied by the establishment of non-diamond
carbon phases at 1353 cm−1 and 1453 cm−1 at the initial stage of polishing and 1580 cm−1 at the intermediate stage of polishing. The non-diamond phases vanish after final fine polishing at moderate temperatures
and pressures. Photoluminescence of defect centers determined by an Ar+ laser (λlexct= 514.532 nm) showed that nitrogen-related centers with two zero-phonon lines at 2.156 eV and 1.945 eV and a silicon-related
center with a zero-phonon line at 1.681 eV are the only detectable defects in the samples.
Received: 26 July 1999 / Accepted: 15 November 1999 相似文献
123.
Together with detection and use of protective clothing, decontamination is the third important part in NBC defence and NBC protection. Enzymes play an important role in the research field of new and environmentally friendly decontaminants. In 1946, organophosphate cleaving enzymes were first mentioned, and in the next decades further enzymes (i.e., DFPase) against G‐type nerve agents were discovered. After the cloning of the DFPase gene sequence in the 90s, the potential of DFPase as an environmentally friendly decontaminant was shown. In technical decontamination experiments, it was shown that the conditions for an enzyme‐based decontamination concept could be met for one class of chemical agents. However, the success of a general enzyme decontamination concept depends on the discovery of new enzymes against other classes of chemical agents, i.e., mustard and VX. 相似文献
124.
125.
Jaan Unger Marcus Stiemer Alexander Brosius Bob Svendsen Heribert Blum Matthias Kleiner 《International Journal of Solids and Structures》2008,45(2):442-459
The purpose of this work is the development and application of strategies to identify material model parameters for metals at high strain-rates using data obtained from high-speed electromagnetic metal forming. To this end, a staggered algorithm for the finite-element-based numerical solution of the coupled electromagnetic-mechanical boundary-value problem has been developed based on mixed Eulerian–Lagrangian multigrid methods. On this basis, the parameter determination together with a sensitivity analysis and error estimation are carried out. After verifying the validity of this approach using synthetic data sets, it is applied to the identification of material parameters using experimental results from electromagnetic tube forming. 相似文献
126.
Ant colony optimization: Introduction and recent trends 总被引:21,自引:0,他引:21
Ant colony optimization is a technique for optimization that was introduced in the early 1990's. The inspiring source of ant colony optimization is the foraging behavior of real ant colonies. This behavior is exploited in artificial ant colonies for the search of approximate solutions to discrete optimization problems, to continuous optimization problems, and to important problems in telecommunications, such as routing and load balancing. First, we deal with the biological inspiration of ant colony optimization algorithms. We show how this biological inspiration can be transfered into an algorithm for discrete optimization. Then, we outline ant colony optimization in more general terms in the context of discrete optimization, and present some of the nowadays best-performing ant colony optimization variants. After summarizing some important theoretical results, we demonstrate how ant colony optimization can be applied to continuous optimization problems. Finally, we provide examples of an interesting recent research direction: The hybridization with more classical techniques from artificial intelligence and operations research. 相似文献
127.
L. Blum 《Fresenius' Journal of Analytical Chemistry》1886,25(1):519-520
Ohne Zusammenfassung 相似文献
128.
L. Blum 《Fresenius' Journal of Analytical Chemistry》1888,27(1):19-24
Ohne Zusammenfassung 相似文献
129.