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It is known that every conformai embedding of the disk into the extended complex plane possesses a r2-quasiconformal extension across eachr-level line (the r2-property of a domain). We show here that this is a characteristic property of the disk: any simply connected domain which is not a disk does not admit ther 2-property. Supported by the RiP-program of the Volkswagen-Stiftung in the Mathematisches Forschungsinstitut Oberwolfach.  相似文献   
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Skew Models II     
If g and G are the pdf and the cdf of a distribution symmetric around 0 then the pdf 2g(u)G(λ u) is said to define a skew distribution. In this paper, we provide a mathematical treatment of the skew distributions when g and G are taken to come from one of Pearson type II, Pearson type VII or the generalized t distribution.   相似文献   
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Dirac's large number hypothesis (LNH) and the Whitrow-Randall-Sciama relation are related to some cosmological models. The LNH and Whitrow-Randall-Sciama relations are neither equivalent nor consistent in general relativity, but they may both be valid in the Brans-Dicke theory and in another theory considered in this paper.  相似文献   
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Nanoparticles of complex manganites (viz. LaMnO3, La0.67Sr0.33MnO3 and La0.67Ca{0.33}MnO3) have been synthesized using the reverse micellar route. These manganites are prepared at 800‡C and the monophasic nature of all the oxides has been established by powder X-ray diffraction studies. TEM studies show an average grain size of 68, 80 and 50 nm for LaMnO3, La0.67Sr0.33MnO3 and La0.67Ca{0.33}MnO3respectively. Ferromagnetic ordering is observed at around 250 K for LaMnO3, 350 K for La0.67Sr0.33MnO3 and 200 K for La0.67Ca{0.33}MnO3. These Curie temperatures correspond well with those reported for bulk materials with similar composition.  相似文献   
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It is shown that time-dependent temperatures in a transient, conductive system can be approximately modeled by a fractional-order differential equation, the order of which depends on the Biot number. This approximation is particularly suitable for complex shapes for which a first-principles approach is too difficult or computationally time-consuming. Analytical solutions of these equations can be written in terms of the Mittag-Leffler function. The approximation is especially useful if a suitable fractional-order controller is to be designed for the system.  相似文献   
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Laser-based electronic speckle interferometry (ESI) techniques, viz., electronic speckle pattern interferometry (ESPI) and electronic speckle shearographic interferometry (ESSI) are used for testing of spacecraft structural components. The combined ESPI and ESSI system developed in house was successfully used for the non-destructive evaluation (NDE) of honeycomb sandwich panels and propellant tanks of Indian Space Research Organization (ISRO). Debonds between face sheet and the honeycomb core were identified using (i) thermal and (ii) dual vacuum stressing methods. On-line NDE of the propellant tanks under internal pressure loading for identification of the minute cracks and thickness reduction areas were successfully implemented by ESI.  相似文献   
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