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排序方式: 共有54条查询结果,搜索用时 15 毫秒
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Hagen A Steiner M Raschke MB Lienau C Hertel T Qian H Meixner AJ Hartschuh A 《Physical review letters》2005,95(19):197401
The dynamics of excitons in individual semiconducting single-walled carbon nanotubes was studied using time-resolved photoluminescence (PL) spectroscopy. The PL decay from tubes of the same (n,m) type was found to be monoexponential, however, with lifetimes varying between less than 20 and 200 ps from tube to tube. Competition of nonradiative decay of excitons is facilitated by a thermally activated process, most likely a transition to a low-lying optically inactive trap state that is promoted by a low-frequency phonon mode. 相似文献
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F. D. Berg M. Pfeiffer O. Schwalb M. Appenheimer W. Döring M. Franke W. Kühn V. Metag W. Niebur R. Novotny J. Ritman M. Röbig H. Ströher A. Boonstra H. Löhner A. Raschke L. Venema H. W. Wilschut N. Brummund W. Henning S. Hlavac R. Holzmann R. S. Simon 《Zeitschrift für Physik A Hadrons and Nuclei》1990,337(3):351-352
π0 -production probability of (9± 2)· 10? 3 per20Ne+Al reaction has been measured at 350 MeV/u using the Two Arm Photon Spectrometer TAPS. This yield is consistent with an interpolation of published π-production rates in heavy ion collisions. 相似文献
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P Kelle H Schneider C Raschke H Shirazi 《The Journal of the Operational Research Society》2013,64(3):313-325
Since highway improvement project selection requires screening thousands of road segments with respect to crashes for further analysis and final project selection, we provide a two-step project selection methodology and describe an application case to demonstrate its advantages. In the first step of the proposed methodology, we will use odds against observing a given crash count, injury count, run-off road count and so on as measures of risk and a multi-criteria pre-selection technique with the objective to decrease the number of prospective improvement locations. In the second step, the final project selection is accomplished based on a composite efficiency measure of estimated cost, benefit and hazard assessment (odds) under budget constraints. To demonstrate the two-step methodology, we will analyze 4 years of accident data at 23?000 locations where the final projects are selected out of several hundred of potential locations. 相似文献
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P. Dietrich F. Michalik R. Schmidt C. Gahl G. Mao M. Breusing M. B. Raschke B. Priewisch T. Elsässer R. Mendelsohn M. Weinelt K. Rück-Braun 《Applied Physics A: Materials Science & Processing》2008,93(2):285-292
A mild and efficient procedure has been developed to obtain covalently attached self-assembled monolayers (SAMs) on Si(111)
with photochromic azobenzene head-groups. Starting from neat or diluted carboxylic acid functionalized monolayers on-chip
coupling reactions were applied to attach hydroxyl-functionalized azobenzene units to the SAMs by ester bond formation. The
modified surfaces were characterized by high-resolution X-ray photoelectron spectroscopy (XPS), transmission Fourier transform
infrared spectroscopy (FT-IR), and contact angle measurements. Reversible cis
↔
trans isomerizations of photoswitchable SAMs were monitored by wettability measurements.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
Dedicated with respect and compliments to Professor Helmut Schwarz on the occasion of his 65th birthday. 相似文献
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In this study,the three dimensional nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by transmission electron tomography.After annealing treatment,either at elevated temperature or during slow solvent evaporation,nanoscale interpenetrating networks are formed with high crystalline order and favorable concentration gradients of both components through the thickness of the photoactive layer.Such a tailored morphology acco... 相似文献
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Louis A. Florence Edward C. Kinzel Robert L. Olmon James C. Ginn Markus B. Raschke Glenn D. Boreman 《Infrared Physics & Technology》2012,55(6):449-453
Tapered slot antennas (TSAs) consist of a planar non-resonant structure which couples incident radiation to a propagating waveguide mode. They are commonly used at microwave and radio frequencies because they are fundamentally broadband and have small profiles. Because of their planar layout and broadband response they have recently been scaled to infrared frequencies where they have advantages for sensing and energy harvesting. We use scattering-type scanning near-field optical microscopy (s-SNOM) to study the mode transformation of two types of TSA operating in the thermal infrared (λ0 = 10.6 μm) with respect to electric field amplitude and phase. The results agree well with simulation showing both the phase reversal across the tapered slot and the traveling of wave fronts along the tapered slot, yet they also reveal high sensitivity of device performance to inhomogeneities in the geometry or illumination. This study will aid future design and analysis of practical non-resonant antennas operating at optical and infrared frequencies. 相似文献
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F. D. Berg A. Boonstra H. P. Braak N. Brummund W. Döring M. Franke P. Gonthier W. Henning W. T. Hering S. Hlaváč R. Holzmann B. Krusche W. Kühn H. Lohner R. Lorencz V. Metag W. Niebur R. Novotny R. Ostendorf M. Pfeiffer A. Raschke J. Ritman M. Röbig Y. Schutz O. Schwalb R. S. Simon H. Ströher L. Venema H. W. Wilschut 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(3):297-302
The production of
0 and mesons has been studied in the reactions20Ne +Al at 350 MeV/u and40Ar + Ca at 1.0 GeV/u. Rapidity distributions and transverse momentum spectra have been measured and are compared to thermal distributions.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献