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61.
62.
It is shown that the restriction of automorphisms of a compact projective plane to a closed Baer subplane or to an open subgeometry, respectively, is a quotient mapping (in contrast to restrictions to arbitrary subgeometries). In the proof, we investigate lineations in towers of Baer subplanes. 相似文献
63.
64.
Theo F. Nonnenmacher 《Zeitschrift für Physik B Condensed Matter》1980,38(4):327-333
We discuss the kinetics of phase separation based on the mechanism of spinodal decomposition. The starting point is Boltzmann's transport equation. A perturbation theory will be developed leading to a hierarchy of differential equations for the local density. The first member of this hierarchy is a nonlinear wave-type equation, which linearized version will be solved in order to discuss the behaviour of the amplification factor. Additionally, we compare our results with those of standard diffusion-type approximations and molecular dynamics calculations.Research supported in part by National Science Foundation, Grant ENG-7 515 882-A01 相似文献
65.
Theo Kost 《Fresenius' Journal of Analytical Chemistry》1964,203(4):260-265
Zusammenfassung Es wird eine Apparatur für die Fluorbestimmung nach Willard-Winter in Phosphorsäure, Alkali- und Erdalkaliphosphaten beschrieben, die eine wartungsfreie Destillation ermöglicht und in Verbindung mit einer vereinfachten photometrischen Bestimmung in kurzer Zeit brauchbare Resultate liefert.
Summary An apparatus is described for the determination of fluorine according to Willard-Winter in phosphoric acid, alkali and alkaline-earth phosphates. The device permits a distillation without attendance and in combination with a simplified photometric determination satisfactory results may be obtained within a short time.相似文献
66.
Theo Tschudi Gerd Herziger 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1973,24(1):127-130
Zusammenfassung In glasfaserarmierten Kunststoffen treten beim Reissen von Fasern oder Lösen der Fasern vom Bindemittel schwache Bruchgeräusche auf. Diese rufen als Sekundäreffekte stark gedämpfte Oberflächenschwingungen des Werkstückes hervor. Die Schwingungen können durch Analyse des zeitlichen Verhaltens der Interferenzstreifen in einer interferometrischen Anordnung empfindlich nachgewiesen werden.
In armored synthetic materials fracture noise is appearing if single fibres are breaking up or are separated from the bound material. This process gives rise to strong damped surface oscillations of the synthetic material. The amplitude and frequency of this oscillation can be detected with high sensitivity by an analysis of the time behaviour of the interference pattern in a interferometric experimental arrangement.相似文献
67.
68.
Mitrofanov O Lang DV Kloc C Wikberg JM Siegrist T So WY Sergent MA Ramirez AP 《Physical review letters》2006,97(16):166601
A molecular exciton signature is established and investigated under different ambient conditions in rubrene single crystals. An oxygen-related band gap state is found to form in the ambient atmosphere. This state acts as an acceptor center and assists in the fast dissociation of excitons, resulting in a higher dark and photoconductivity of oxidized rubrene. The band gap state produces a well-defined photoluminescence band at an energy 0.25 eV below the energy of the 0-0 molecular exciton transition. Two-photon excitation spectroscopy shows that the states are concentrated near the surface of naturally oxidized rubrene. 相似文献
69.
Frost RL Cejka J Weier ML Martens W Kloprogge JT 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,64(2):308-315
Raman spectroscopy has been used to study the molecular structure of a series of selected uranyl silicate minerals, including weeksite K2[(UO2)2(Si5O13)].H2O, soddyite [(UO2)2SiO4.2H2O] and haiweeite Ca[(UO2)2(Si5O12(OH)2](H2O)3 with UO2(2+)/SiO2 molar ratio 2:1 or 2:5. Raman spectra clearly show well resolved bands in the 750-800 cm-1 region and in the 950-1000 cm-1 region assigned to the nu1 modes of the (UO2)2+ units and to the (SiO4)4- tetrahedra. For example, soddyite is characterized by Raman bands at 828.0, 808.6 and 801.8 cm-1 (UO2)2+ (nu1), 909.6 and 898.0 cm-1 (UO2)2+ (nu3), 268.2, 257.8 and 246.9 cm-1 are assigned to the nu2 (delta) (UO2)2+. Coincidences of the nu1 (UO2)2+ and the nu1 (SiO4)4- is expected. Bands at 1082.2, 1071.2, 1036.3, 995.1 and 966.3 cm-1 are attributed to the nu3 (SiO4)4-. Sets of Raman bands in the 200-300 cm-1 region are assigned to nu2 (delta) (UO2)2+ and UO ligand vibrations. Multiple bands indicate the non-equivalence of the UO bonds and the lifting of the degeneracy of nu2 (delta) (UO2)2+ vibrations. The (SiO4)4- tetrahedral are characterized by bands in the 470-550 cm-1 and in the 390-420 cm-1 region. These bands are attributed to the nu4 and nu2 (SiO4)4- bending modes. The minerals show characteristic OH stretching bands in the 2900-3500 cm-1 and 3600-3700 cm-1. 相似文献
70.
We investigate polymer stretching by fluctuating flow fields via numerical solutions of the Brownian dynamics of multibead polymer chains taking into account nonlinear elasticity, hydrodynamic interactions and good solvent, excluded volume interaction effects. By varying the scaling exponent of the energy spectrum whilst keeping the same Reynolds and Deborah numbers, as well as microscale length and turnover times, we show that steeper spectra are associated with stronger stretching. We compute the probability density functions of chain length, and explain their main features by examining explicit molecular histories. We quantify the interaction between strain rate tensor structure and chain geometry as a means of understanding better the different stretching mechanisms in mild, moderate and strong polymer stretching regimes. 相似文献