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41.
Pekka Tukia 《Journal d'Analyse Mathématique》2004,92(1):137-189
A classical Teichmüller sequence is a sequence of quasiconformal mapsf
i with complex dilatations of the form
, where φ is a quadratic differential and 0≤k
i<1 are numbers such thatk
i→1 asi→∞. This situation occurs in the Teichmüller theory when one moves along a Teichmüller geodesic toward the boundary. The central
result is that if τ is a vertical trajectory associated to φ, then there is often, for instance if the sequence is normalized
so thatf
i fix 3 points, a subsequence such thatf
i tend either toward a constant or an injective map of τ (Theorem 4.1). If the limit is injective, it is an embedding of τ
if τ does not contain points such that τ returns infinitely often to every neighborhood of the point. The main idea is to
composef
i locally with a map ϱi so that the composed mapf
iϱi is conformal and coincides withf
i on τ. Normal family arguments are applied to the sequencef
iϱi. Various extensions are presented.
The research for this paper has been supported by the project 51749 of the Academy of Finland. 相似文献
42.
Using Corbino samples we have observed oscillatory dc conductance in a high-mobility two-dimensional electron system when it is subjected to crossed microwave and magnetic fields. At the strongest of the oscillation minima the conductance is found to be vanishingly small, indicating a macroscopic insulating state associated with this minimum. With increasing voltage bias, a crossover from Ohmic to electron-heating regime is observed. 相似文献
43.
Nuclear spin lattice relaxation rates were measured in normal and superconducting (sc) rhodium with nuclear polarizations up to p = 0. 55. This was sufficient to influence the sc state of Rh, whose T(c) and B(c) are exceptionally low. Because B(c)相似文献
44.
45.
Bokwon Yoon Dr. Pekka Koskinen Dr. Bernd Huber Oleg Kostko Bernd von Issendorff Prof. Hannu Häkkinen Prof. Michael Moseler Dr. Uzi Landman Prof. 《Chemphyschem》2007,8(1):157-161
Ground-state structures and other experimentally relevant isomers of Au(15) (-) to Au(24) (-) clusters are determined through joint first-principles density functional theory and photoelectron spectroscopy measurements. Subsequent calculations of molecular O(2) adsorption to the optimal cluster structures reveal a size-dependent reactivity pattern that agrees well with earlier experiments. A detailed analysis of the underlying electronic structure shows that the chemical reactivity of the gold cluster anions can be elucidated in terms of a partial-jellium picture, where delocalized electrons occupying electronic shells move over the ionic skeleton, whose geometric structure is strongly influenced by the directional bonding associated with the highly localized "d-band" electrons. 相似文献
46.
Pekka NikkilÄ Tom Johnsson Heikki Rosenqvist Leena Toivonen 《Applied biochemistry and biotechnology》1996,59(3):245-257
Growth and fatty acid composition of two lactobacilli,Lactobacillus büchneri andLactobacillus fermentum, were studied at different pHs of the media in a small-scale fermenter with particular interest in lactobacillic acid production
of the cultures. Generally, the total fatty acid content of the bacterial cells increased with increasing culture age. The
production of lactobacillic acid was affected in the two lactobacilli by both culture age and pH of the media, but in a very
different manner. In L.büchneri cultures, the relative proportion of lactobacillic acid was highest when the pH was lowest (pH 4.5), whereas inL. fermentum cultures, the proportion of lactobacillic acid was highest at pH 7.0. The pH of the medium affected not only the relative
proportion of lactobacillic acid, but also biomass production and total fatty acid accumulation of the cultures. Thus, by
controlling the pH of the cultures, the volumetric yield of lactobacillic acid could be improved considerably compared to
cultures without pH control. 相似文献
47.
Multivariate Gaussian criteria in SMAA 总被引:2,自引:0,他引:2
Risto Lahdelma Simo Makkonen Pekka Salminen 《European Journal of Operational Research》2006,170(3):79-970
We consider stochastic multicriteria decision-making problems with multiple decision makers. In such problems, the uncertainty or inaccuracy of the criteria measurements and the partial or missing preference information can be represented through probability distributions. In many real-life problems the uncertainties of criteria measurements may be dependent. However, it is often difficult to quantify these dependencies. Also, most of the existing methods are unable to handle such dependency information.In this paper, we develop a method for handling dependent uncertainties in stochastic multicriteria group decision-making problems. We measure the criteria, their uncertainties and dependencies using a stochastic simulation model. The model is based on decision variables and stochastic parameters with given distributions. Based on the simulation results, we determine for the criteria measurements a joint probability distribution that quantifies the uncertainties and their dependencies. We then use the SMAA-2 stochastic multicriteria acceptability analysis method for comparing the alternatives based on the criteria distributions. We demonstrate the use of the method in the context of a strategic decision support model for a retailer operating in the liberated European electricity market. 相似文献
48.
Two new chiral unsymmetrical (non-C2-symmetric) Schiff-base ligands containing salicylaldehyde and 1-(2-hydroxyphenyl)ketone units were synthesized from (R,R)-1,2-diphenylethylenediamine as the chiral diamine using a stepwise approach. The Mn(III) complexes of the ligands were subsequently used as catalysts in asymmetric epoxidation of unfunctionalized alkenes and the results were compared with those obtained using typical C2-symmetric Mn(III)–salen complexes. Possible reasons for the differences in reactivity and selectivity between the two types of catalysts are briefly discussed. 相似文献
49.
Simultaneous analysis of catechol‐O‐methyl transferase activity,S‐adenosylhomocysteine and adenosine
Novel HPLC method utilizing UV‐detection was developed to analyse catechol‐O‐methyltransferase (COMT) products, vanillic acid and isovanillic acid, S‐adenosylhomocysteine (SAH) and adenosine formed from dihydroxybenzoic acid and S‐adenosyl‐L‐methionine (SAM) by incubation of the rat tissues. Entacapone, a COMT inhibitor, prevented the formation of SAH only partially in the striatal homogenate whereas in the kidney homogenate the increase of SAH was prevented by entacapone. In conclusion, this method was reliable, rapid and simple. COMT seemed to be partially responsible on the SAM utilizing methylations in the striatal homogenates while in the high COMT activity tissue, COMT was the main SAH producing methyltransferase. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
50.