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151.
We launch surface plasmons from one end of a silver nanowire by asymmetric illumination with white light and use plasmon-to-light scattering at the nanowire ends to probe spectroscopically the plasmonic Fabry-Perot wire modes. The spectral positions of the maxima and minima in the scattered intensity from both nanowire ends are found to be either in-phase or out-of-phase, depending on the nanowire length and the spectral range. This behavior can be explained by a generalized Fabry-Perot model. The turnover point between the two regimes is sensitive to the surface plasmon round trip losses and thus opens a new possibility for detecting changes of the optical absorption in the nanowire environment. 相似文献
152.
Keil R Lahini Y Shechtman Y Heinrich M Pugatch R Dreisow F Tünnermann A Nolte S Szameit A 《Optics letters》2012,37(5):809-811
It is experimentally demonstrated that perfect imaging is possible in disordered wave guiding media, provided that the disorder is off-diagonal, i.e., that only the spacing varies randomly between the otherwise identical lattice sites. On-diagonal disorder or Kerr nonlinearity destroys the imaging. 相似文献
153.
154.
PURPOSE: The aim of this experimental study was to evaluate the potential of a simple expiration technique by means of magnetic resonance imaging (MRI) in an animal model to detect pulmonary air-trapping areas after artificial bronchial obstruction. MATERIAL AND METHODS: Sixteen pigs were evaluated by means of a modified T1-weighted FLASH with fat saturation in respiratory arrest (TR=4.6 ms, TE=1.8 ms, alpha=10 degrees, S.D.=3-5 mm). A measurement of the signal intensity (SI) in the peripheral lung tissue was made in both inspiration and expiration before and after inhalation of 2 ml of 0.5% acetylcholine to simulate a bronchial obstruction. A final measurement of the lung SI was also made after bronchospasmolytic induction through salbutamol (beta2-mimetic bronchodilator). RESULTS: In expiration, a mean SI increase in peripheral lung tissue of about 183% was seen in comparison to inspiration (mean SI increase of 11-32). After inhalation of 0.5% acetylcholine, the expirational signal increase in peripheral lung tissue was only 114% of the original SI. The expirational signal homogeneity decreased after inhalation of acetylcholine. After inhalation of salbutamol, the lung tissue signal elevation in expiration was 193%. CONCLUSION: We interpret the low expiratory signal elevation after acetylcholine inhalation as a result of an air-trapped bronchial constriction in certain areas. The simple expiratory technique in an animal model showed that it is suitable to demonstrate obstructive air trapping using MRI. 相似文献
155.
Triangular symmetry stabilizes a novel non-Fermi-liquid phase in the three-impurity Kondo model with frustrating antiferromagnetic interactions between half-integer impurity spins. The phase arises without fine-tuning of couplings, and is stable against magnetic fields and particle-hole symmetry breaking. We find a conformal field theory describing this phase, verify it using the numerical renormalization group, and extract various exact, universal low-energy properties. Signatures predicted in electrical transport may be testable in scanning tunneling microscopy or quantum-dot experiments. 相似文献
156.
Ebel A Dreher W Leibfritz D 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2006,182(2):330-338
The influence of noise on the standard deviation of spectral integrals is examined. Calculations assuming discrete Fourier-transform data are compared with Monte-Carlo simulations. The effects of zero-filling and apodization are examined for free-induction-decay (FID) signals and for symmetric spin-echo signals in one and two dimensions, with particular attention to features not previously presented in the literature. Findings suggest that for mild apodization, the known sensitivity enhancement due to zero-filling in either the real or the imaginary part signal [E. Bartholdi, R.R. Ernst, Fourier spectroscopy and the causality principle, J. Magn. Reson., 11 (1973) 9-19] is maintained; however, for stronger apodization filters, this enhancement can be obliterated completely. It is shown that results obtained by analysis of one-dimensional signals can be readily applied to multi-dimensional data. Furthermore, zero-filling has a negligible effect for symmetric spin-echo signals with implications for signal averaging in magnetic resonance imaging and spectroscopic imaging. 相似文献
157.
Tomomi Ishikawa LuChang Jin Huey-Wen Lin Andreas Sch?fer Yi-Bo Yang Jian-Hui Zhang Yong Zhao 《中国科学:物理学 力学 天文学(英文版)》2019,(9)
正Recent years have witnessed rapid progress in calculating parton distribution functions (PDFs), rather than just their moments, from lattice QCD [1-9]. The most remarkable aspect of such calculations is that one can connect appropriately chosen Euclidean correlation functions calculable on the lattice to PDFs through a perturbative matching relation. This can be understood in the framework of the large-momentum 相似文献
158.
Bei Verschleißuntersuchungen mit einer Stift-Scheibe-Apparalur, in der an Stelle des Stifles eine neutronenaktivierte Stahlkugel eingesetzt wird, wird in unserem Laboratorium außer Radioaktivitätsmessungen mit Zählgeräten auch die Autoradiographie angewandt. Dazu wird der Schmierstoff mit dem losen Verschleiß abgewaschen und der festhaftende (adhäsive) Verschleiß durch Kontaktautoradiographie abgebildet. Die notwendigen Expositionszeiten liegen meist bei 2 bis 3 Wochen, wobei im allgemeinen TF 14-Filmmaterial verwendet wird. Experimentelle Beispiele werden gezeigt und diskutiert. Mit neutronenaktivierten Stahlkugdn verschiedener Abklingzeit wurde durch Verghieh von Radioaktivitätsmessungen mit Zählgeräten und Autoradiographie gezeigt, daß die Schwärzung vorwiegend von der ß-Strahlung der entstandenen Radionuklide herrührt. 相似文献
159.
Hoefman M Aphecetche L Bacelar JC Delagrange H Descouvemont P Diaz J d'Enterria D van Goethem M Holzmann R Huisman H Kalantar-Nayestanaki N Kugler A Lohner H Marques FM Martinez G Messchendorp JG Ostendorf RW Schadmand S Siemssen RH Simon RS Schutz Y Timmermans R Turrisi R Volkerts M Wagner V Weller H 《Physical review letters》2000,85(7):1404-1407
160.
Novel interconnection scheme for thin‐film silicon solar modules with conductive intermediate reflector 下载免费PDF全文
Bugra Turan Andreas Bauer Andreas Lambertz Tsvetelina Merdzhanova Stefan Haas 《固体物理学:研究快报》2015,9(2):103-107
Intermediate reflector layers are commonly used for light man‐agement purposes in multi‐junction silicon based devices containing a‐Si:H top‐ and µc‐Si:H bottom‐sub‐cells. A low resistance of such layers can have a severe impact on the solar module performance due to shunting of the bottom sub‐cell by the P2 scribe. A common solution for this problem is the use of an additional scribe line. However, not only the additional processing step is disadvantageous but also the dead area losses are increased as well by the additional scribe. This work introduces a novel solar cell stripe interconnection scheme that requires only three scribing processes with similar dead area losses as they would be apparent in the standard interconnection scheme. An implementation to mini modules shows no negative impact on the electrical properties and simultaneously reducing the required number of scribing steps. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献