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101.
We study sets of points at which ω1 sequences of real functions from a given class F converge. As F we consider continuous functions, first class of Baire, Borel
measurable functions, functions with Baire property and Lebesgue measurable functions. Connections of those problem with additional
set-theoretic axioms are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
102.
103.
We present a systematic exposition of the Lagrangian field theory for the massive spin-2 field generated in higher-derivative gravity upon reduction to a second-order theory by means of the appropriate Legendre transformation. It has been noticed by various authors that this nonlinear field overcomes the well-known inconsistency of the theory for a linear massive spin-2 field interacting with Einstein’s gravity. Starting from a Lagrangian quadratically depending on the Ricci tensor of the metric, we explore the two possible second-order pictures usually called “(Helmholtz-)Jordan frame” and “Einstein frame.” In spite of their mathematical equivalence, the two frames have different structural properties: in Einstein frame, the spin-2 field is minimally coupled to gravity, while in the other frame it is necessarily coupled to the curvature, without a separate kinetic term. We prove that the theory admits a unique and linearly stable ground state solution, and that the equations of motion are consistent, showing that these results can be obtained independently in either frame (each frame therefore provides a self-contained theory). The full equations of motion and the (variational) energy-momentum tensor for the spin-2 field in Einstein frame are given, and a simple but non-trivial exact solution to these equations is found. The comparison of the energy-momentum tensors for the spin-2 field in the two frames suggests that the Einstein frame is physically more acceptable. We point out that the energy-momentum tensor generated by the Lagrangian of the linearized theory is unrelated to the corresponding tensor of the full theory. It is then argued that the ghost-like nature of the nonlinear spin-2 field, found long ago in the linear approximation, may not be so harmful to classical stability issues, as has been expected. 相似文献
104.
An evanescent light penetrating an atomic vapour near a dielectric surface could be a probe for many atom-boundary phenomena. We show the possibility of very sensitive detection of the resonant atom–light interaction near the surface by using the optogalvanic effect for an evanescent wave. We observe a narrowing of the profile of the detected atomic line, and we point out some properties of the optogalvanic effect in the evanescent wave. 相似文献
105.
Leszek Gasiński Dumitru Motreanu Nikolaos S. Papageorgiou 《Proceedings Mathematical Sciences》2006,116(2):233-255
We consider a semilinear elliptic equation with a nonsmooth, locally Lipschitz potential function (hemivariational inequality).
Our hypotheses permit double resonance at infinity and at zero (double-double resonance situation). Our approach is based
on the nonsmooth critical point theory for locally Lipschitz functionals and uses an abstract multiplicity result under local
linking and an extension of the Castro-Lazer-Thews reduction method to a nonsmooth setting, which we develop here using tools
from nonsmooth analysis. 相似文献
106.
107.
Jadwiga Skupiska Monika Karpiska Leszek Wachowski Magdalena Hofman 《Reaction Kinetics and Catalysis Letters》2004,82(2):311-316
A simple catalytic system containing metallic palladium, iron and iodine has been shown to be very active in the carbonylation
of nitrobenzene to carbamate. The influence of the components of the catalytic system studied on its selectivity and activity
has been established. It has been found that the catalytic activity of palladium supported on carbon (using both lignite coal
and bituminous coal) was not lower than the activity of metallic palladium.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
108.
A Monte Carlo simulation of the concentration dependence of the fluorescence quantum yield M and emission anisotropyr
M of a system containing dye molecules in the form of monomers M and clusters T (statistical pairs and trimers) playing the role of the imperfect traps for nonradiative excitation energy transfer (NET) has been carried out. The simulation has been made for determined values of Förster critical distancesR
0
MM
andR
0
MT
and for several values ofR
0
TM
andR
0
TT
, assuming that the energy may be transferred from M* to T as well as from T* to M (reverse nonradiative energy transfer, RNET). It was shown that the RNET process in the range of high concentrations may strongly change the values ofr
M as well as those of M. For emission anisotropyr
M an effect of repolarization was observed which decreases rapidly with increasingR
0
TM
andR
0
TT
. A very good agreement between the simulation results of M and the theoretical model with no adjustable parameters was found. In the model, the RNET process and influence of correlation between active molecules on energy migration among monomers were taken into account. 相似文献
109.
Valensin D Mancini FM Łuczkowski M Janicka A Wisniewska K Gaggelli E Valensin G Łankiewicz L Kozlowski H 《Dalton transactions (Cambridge, England : 2003)》2004,(1):16-22
The copper(II) binding features of the APP(145-155) and APP(145-157) fragments of the amyloid precursor protein, Ac-Glu-Thr-His-Leu-His-Trp-His-Thr-Val-Ala-Lys-NH2 and Ac-Glu-Thr-His-Leu-His-Trp-His-Thr-Val-Ala-Lys-Glu-Thr-NH2 were studied by NMR spectroscopy and NMR findings were supported by UV-vis, CD and EPR spectra. Potentiometric measurements were performed only for the more soluble Ac-Glu-Thr-His-Leu-His-Trp-His-Thr-Val-Ala-Lys-Glu-Thr-NH2 peptide fragment. The following was shown: (i) the imidazole rings of all the three His residues are involved in metal coordination; (ii) metal binding induces ionisation of Leu-148 and His-149 amide nitrogens that complete the donor set to copper(II) in the species dominant at neutral pH; (iii) the unusual coordination scheme of the His-Xxx-His-Xxx-His consensus sequence justifies the high specificity for Cu(II) when compared to SOD-like or albumin-like peptides or even in amyloid Abeta fragments. The present findings may represent the key for interpreting the observed requirement of His residues conservation for the redox cycling between Cu(II) and Cu(I) by soluble APP. 相似文献
110.
Cheng-yi LiiChia-ding Liao Leszek StobinskiPiotr Tomasik 《European Polymer Journal》2002,38(8):1601-1606
Polymerization of ethylene was initiated by low-pressure glow plasma generated in this gas. Depending on starch present in this plasma polymerization could be considered either as graft-polymerization of ethylene onto starch or homopolymerization. Result of the treatment of cassava, corn, potato, rice Indica, sweet potato, and waxy corn starches with ethylene plasma was analyzed by means of high-performance size exclusion chromatography, X-ray powder diffraction, thermogravimetry, digestion with β-amylase, and scanning electron microscopy. Analyses suggested that graft-polymerization occurred on sweet potato and rice starch. With other starches homopolymerization of ethylene on granules took place. 相似文献