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41.
Cosimo Bambi 《理论物理通讯》2009,(7):78-80
The possibility of stable or quasi-stable Planck mass black hole remnants as solution to the black hole information paradox is commonly believed phenomenologically unacceptable. Since we need a black hole remnant for every possible initial state, the number of remnants is expected to be infinite and that would lead to remnant pair production in any physical process with a total available energy roughly exceeding the Planck mass. In this note I point out that a positive cosmological constant of the Universe would naturally lead to an upper bound on the number of possible remnants. 相似文献
42.
Roberto Grisorio Claudia Piliego Paola Fini Pinalysa Cosma Piero Mastrorilli Giuseppe Gigli Gian Paolo Suranna Cosimo Francesco Nobile 《Journal of polymer science. Part A, Polymer chemistry》2008,46(18):6051-6063
The synthesis of new random poly(2,7‐fluorenylene‐vinylene)s was achieved by a Suzuki–Heck cascade polymerization reaction. The poly(fluorenylene‐vinylene) base structure was modified by the regio‐random incorporation of 1‐cyano‐2,5‐phenylene as electron withdrawing unit ( CN‐PFV1 ) and its properties were compared with terpolymers also embodying 1,4‐dioctyloxy‐2,5‐phenylene ( CN‐PFV2 ) or 3,6‐N‐octylcarbazole ( CN‐PFV3 ) as electron‐donating moieties. Thermal analysis revealed a high thermal stability (Td > 389 °C) and the absence of glass transitions for all polymers. Cyclic voltammetry indicated a high electron affinity of the materials (2.96–3.21 eV) attributed to the presence of the cyano‐containing comonomer. In dilute solutions, the copolymers showed a broad green fluorescence with quantum yields ranging from 0.42 to 0.79, while in the solid state, a relatively narrow emission centered at ~ 560 nm, governed by the low‐energy segments within the π‐conjugated backbone, was observed. The electroluminescence properties of the materials were tested in OLED devices of ITO/PEDOT‐PSS/ CN‐PFV1‐3 /Ca/Al or ITO/PEDOT‐PSS/ CN‐PFV1‐3 /Alq3/Ca/Al configurations, showing a bright green‐yellow emission that, in the case of CN‐PFV2 , reached 1403 cd/m2 with efficiencies as high as 0.13 cd/A. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6051–6063, 2008 相似文献
43.
The Arnowitt–Deser–Misner (ADM) evolution equations for the induced metric and the extrinsic-curvature tensor of the spacelike surfaces which foliate the space-time manifold in canonical general relativity are a first-order system of quasi-linear partial differential equations, supplemented by the constraint equations. Such equations are here mapped into another first-order system. In particular, an evolution equation for the trace of the extrinsic-curvature tensor K is obtained whose solution is related to a discrete spectral resolution of a three-dimensional elliptic operator
of Laplace type. Interestingly, all nonlinearities of the original equations give rise to the potential term in
. An example of this construction is given in the case of a closed Friedmann–Lemaitre–Robertson–Walker universe. Eventually, the ADM equations are re-expressed as a coupled first-order system for the induced metric and the trace-free part of K. Such a system is written in a form which clarifies how a set of first-order differential operators and their inverses, jointly with spectral resolutions of operators of Laplace type, contribute to solving, at least in principle, the original ADM system. 相似文献
44.
Cosimo Cardellicchio Francesco Naso Maria Annunziata M. Capozzi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1161-1170
Abstract Grignard reagents were found to displace carbanionic leaving groups from suitable sulfinyl compounds. Because the process occurred with full inversion at the sulfinyl group, it was possible to set up an easy and straightforward route to chiral nonracemic sulfoxides. The starting compounds were easily produced, mainly by enantioselective oxidation of prochiral sulfides, and then the carbon-for-carbon displacement was effected with formation of a variety of new enantiopure sulfoxides. 相似文献
45.
Spin Hall Magnetoresistance and Spin Nernst Magnetothermopower in a Rashba System: Role of the Inverse Spin Galvanic Effect 下载免费PDF全文
In ferromagnet/normal‐metal bilayers, the sensitivity of the spin Hall magnetoresistance and the spin Nernst magnetothermopower to the boundary conditions at the interface is of central importance. In general, such boundary conditions can be substantially affected by current‐induced spin polarizations. In order to quantify the role of the latter, we consider a Rashba two‐dimensional electron gas with a ferromagnet attached to one side of the system. The geometry of such a system maximizes the effect of current‐induced spin polarization on the boundary conditions, and the spin Hall magnetoresistance is shown to acquire a non‐trivial and asymmetric dependence on the magnetization direction of the ferromagnet. 相似文献
46.
Roberto Grisorio Pinalysa Cosma Piero Mastrorilli Gian Paolo Suranna Cosimo Francesco Nobile 《Tetrahedron》2008,64(37):8738-8745
The preparation and properties of the first spirocyclohexane-functionalized bifluorene-based monodispersed molecular materials is described. The obtained compounds were characterized by 1H NMR, 13C{1H} NMR, IR, DSC, UV-vis and photoluminescence both in solution and in the solid state. The molecules show emissions ranging from the blue to the blue-green region, and higher glass transition temperatures and spectral stability with respect to the analogous compounds containing 9,9,9′,9′-tetrahexyl-[2,2′]-bifluorene core. The materials were used as active layers in electroluminescent devices with ITO/PEDOT-PSS/SB1-4/Ca/Al and ITO/PEDOT-PSS/SB1-4/BCP/Ca/Al configurations. 相似文献
47.
Angelico R Ceglie A Cuomo F Cardellicchio C Mascolo G Colafemmina G 《Langmuir : the ACS journal of surfaces and colloids》2008,24(6):2348-2355
This article focuses on reactions performed in nanostructured environments where the pair of complementary nucleotides, 5'-AMP and 5'-UMP, are converted into their amphiphilic derivatives. The synthesis is carried out by using the hydrophobic reactant dodecyl epoxide (DE) dispersed in a micellar solution based on the cationic surfactant cetyltrimethylammoniumbromide (CTAB). Novel nucleo-lipids monomers and CTAB molecules give rise to the spontaneous self-assembly of catanionic supramolecular structures in water, showing typical Maltese crosses in optical microscopy. In the final colloidal suspensions, mono- and dichained derivatives have been identified in the system incubated with 5'-UMP through LC-QqTOF-MS analysis, whereas only mono-alkylated adducts are found in the analogue reaction with 5'-AMP. A new di-alkylated 5'-UMP adduct is obtained from the 1:1 mixture of both complementary nucleotides, in addition to the nucleo-lipids found in separate systems. Time-resolved DLS measurements reveal very different kinetic processes for aggregates' formation when 5'-UMP, 5'-AMP, or their equimolar combination are used in the reaction mixture. This system as a whole represents a potential experimental model where the effect of both intermolecular interactions and self-association processes can be investigated by tuning the type of nucleobases in the reaction mixtures. 相似文献
48.
49.
Greco G Panzella L Gentile G Errico ME Carfagna C Napolitano A d'Ischia M 《Chemical communications (Cambridge, England)》2011,47(37):10308-10310
An oxygen-dependent biomimetic system for DOPA, dopamine and norepinephrine polymerization exploiting the redox properties of a 5-S-cysteinylDOPA (CD)-melanin polymer is disclosed. Kinetic, chemical and scanning electron microscopy (SEM) evidence indicates conversion of DOPA into a black insoluble polymer encapsulating the active CD-melanin core. 相似文献
50.
We prove an existence result for non-rotational constant mean curvature ends in ${\mathbb{H}^2 \times \mathbb{R}}$ , where ${\mathbb{H}^2}$ is the hyperbolic real plane. The value of the curvature is ${h \in \big(0, \frac{1}{2} \big)}$ . We use Schauder theory and a continuity method for solutions of the prescribed mean curvature equation on exterior domains of ${\mathbb{H}^2}$ . We also prove a fine property of the asymptotic behavior of the rotational ends introduced by Sa Earp and Toubiana. 相似文献