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91.
We examine using Monte Carlo simulations, photon transport in optically ‘thin’ slabs whose thickness L is only a few times the transport mean free path l*, with particles of different scattering anisotropies. The confined geometry causes an auto-selection of only photons with
looping paths to remain within the slab. The results of the Monte Carlo simulations are borne out by our analytical treatment
that incorporates directional persistence by the use of the Ornstein-Uhlenbeck process, which interpolates between the short
time ballistic and long time diffusive regimes. 相似文献
92.
Obliquely propagating altra-low-frequency dust-electromagnetic waves in a self-gravitating, warm, magnetized, two fluid dusty
plasma system have been investigated. Two special cases, namely, dust-Alfvén mode propagating parallel to the external magnetic
field and dustmagnetosonic mode propagating perpendicular to the external magnetic field have also been considered. It has
been shown that effects of self-gravitational field, dust fluid temperature, and obliqueness significantly modify the dispersion
properties of these ultra-low-frequency dust-electromagnetic modes. It is also found that in parallel propagating dust-Alfvén
mode these effects play no role, but in obliquely propagating dust-Alfvén mode or perpendicular propagating dust-magnetosonic
mode the effect of self-gravitational field plays destabilizing role whereas the effect of dust/ion fluid temperature plays
stabilizing role. 相似文献
93.
Rapid and mobile determination of alcoholic strength in wine,beer and spirits using a flow-through infrared sensor 总被引:1,自引:0,他引:1
Dirk W Lachenmeier Rolf Godelmann Markus Steiner Bob Ansay Jürgen Weigel Gunther Krieg 《Chemistry Central journal》2010,4(1):5
Background
Ever since Gay-Lussac's time, the alcoholic strength by volume (% vol) has been determined by using densimetric measurements. The typical reference procedure involves distillation followed by pycnometry, which is comparably labour-intensive and therefore expensive. At present, infrared (IR) spectroscopy in combination with multivariate regression is widely applied as a screening procedure, which allows one to determine alcoholic strength in less than 2 min without any sample preparation. The disadvantage is the relatively large investment for Fourier transform (FT) IR or near-IR instruments, and the need for matrix-dependent calibration. In this study, we apply a much simpler device consisting of a patented multiple-beam infrared sensor in combination with a flow-through cell for automated alcohol analysis, which is available in a portable version that allows for on-site measurements. 相似文献94.
Szabolcs Borsányi Ydalia Delgado Stephan Dürr Zoltán Fodor Sándor D. Katz Stefan Krieg Thomas Lippert Dániel Nógrádi Kálmán K. Szabó 《Physics letters. [Part B]》2012
We study QCD thermodynamics using two flavors of dynamical overlap fermions with quark masses corresponding to a pion mass of 350 MeV. We determine several observables on Nt=6 and 8 lattices. All our runs are performed with fixed global topology. Our results are compared with staggered ones and a nice agreement is found. 相似文献
95.
The combination of controlled polymerization techniques and "click" reactions form an efficient platform for the preparation of polymers in various architectures. In this critical review, an update of our 2007 review in Chem. Soc. Rev., we focus on the "click" reactions that have been used widely in the last four years to create new polymer architectures. Not only block copolymers and star-shaped polymers but also cyclic and dendritic macromolecules could be synthesized using these robust "click" reactions (205 references). 相似文献
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Esra Altuntaş Andreas Krieg Anja Baumgaertel Anna C. Crecelius Ulrich S. Schubert 《Journal of polymer science. Part A, Polymer chemistry》2013,51(7):1595-1605
Research in polymer science and engineering is moving from classical methodologies to advanced analytical strategies in which mass spectrometry (MS)‐based techniques play a crucial role. The molecular complexity of polymers requires new characterization tools and approaches to elucidate the detailed structural information. In this contribution, a comparison study of poly(methyl acrylate)s (PMA) using different tandem mass spectrometry techniques (ESI, APCI, and MALDI MS/MS) is reported to provide insights into the macromolecular structure with the aid of a special MS/MS data interpretation software. Collision‐induced dissociation (CID) was utilized to examine the fragmentation pathways of PMAs synthesized via various controlled radical polymerization techniques. All three mass spectrometry techniques are used to analyze structural details of PMAs and the labile end‐groups are determined based on the fragmentation behavior in CID. Fragmentation products were identified which are characteristics for the cleavage between the polymer chain and the end‐group. The application of a tailor‐made software is shown to analyze complex MS/MS data, and it is proven that this kind of software will be helpful for polymer scientists to identify fragmentation products obtained by tandem mass spectrometry similar to the fields of proteomics, metabolomics, genomics, and glycomics. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
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The Ramanujan Journal - A result by Hashimoto and Ueda says that the graded ring of modular forms with respect to $${\mathrm{SO}}(2,10)$$ is a polynomial ring in modular forms of weights... 相似文献