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作者： Cibulka, Josef Kynčl, Jan Mészáros, Viola Stolař, Rudolf Valtr, Pavel Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Malostranské nám. 25 118 00 Praha 1 Czech Republic Department of Applied Mathematics Institute for Theoretical Computer Science Charles University Malostranské nám. 25 118 00 Praha 1 Czech Republic Bolyai Institute University of Szeged Aradi vértanúk tere 1 6720 Szeged Hungary

ISBN: (纸本)3642102166

Bob cuts a pizza into slices of not necessarily equal size and shares it with Alice by alternately taking turns. One slice is taken in each turn. The first turn is Alice's. She may choose any of the slices. In all other turns only those slices can be chosen that have a neighbor slice already eaten. We prove a conjecture of Peter Winkler by showing that Alice has a strategy for obtaining 4/9 of the pizza. This is best possible, that is, there is a cutting and a strategy for Bob to get 5/9 of the pizza. We also give a characterization of Alice's best possible gain depending on the number of slices. For a given cutting of the pizza, we describe a linear time algorithm that computes Alice's strategy gaining at least 4/9 of the pizza and another algorithm that computes the optimal strategy for both players in any possible position of the game in quadratic time. We distinguish two types of turns, shifts and jumps. We prove that Alice can gain 4/9, 7/16 and 1/3 of the pizza if she is allowed to make at most two jumps, at most one jump and no jump, respectively, and the three constants are the best possible. © Springer-Verlag Berlin Heidelberg 2009.

关键词： Clustering algorithms

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An organometallic route to long helicenes (vol 106, pg 13169, 2009)

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PROCEEDINGS OF THE NATIONAL ACADEMY OF scienceS OF THE UNITED STATES OF AMERICA 2009年第41期106卷 17605-17605页

作者： Sehnal, Petr Stara, Irena G. Saman, David Tichy, Milos Misek, Jiri Cvacka, Josef Rulisek, Lubomir Chocholousova, Jana Vacek, Jaroslav Goryl, Grzegorz Szymonski, Marek Cisarova, Ivana Stary, Ivo [a]Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Flemingovo nám. 2 166 10 Prague 6 Czech Republic [b]Center for Nanometer-Scale Science and Advanced Materials Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Reymonta 4 30-059 Krakow Poland [c]Department of Inorganic Chemistry Charles University Albertov 2030 128 40 Prague 2 Czech Republic and [d]Department of Organic Chemistry Charles University Albertov 2030 128 40 Prague 2 Czech Republic

Along with the recent progress in the development of advanced synthetic methods, the chemical community has witnessed an increasing interest in promising carbon-rich materials. Among them, helicenes are unique 3D aromatic systems that are inherently chiral and attractive for asymmetric catalysis, chiral recognition and material science. However, there have been only limited attempts at synthesizing long helicenes, which represent challenging targets. Here, we report on an organometallic approach to the derivatives of undecacyclic helicene, which is based on intramolecular [2 + 2 + 2] cycloisomerization of aromatic hexaynes under metal catalysis closing 6 new cycles of a helicene backbone in a single operation. The preparation of nonracemic compounds relied on racemate resolution or diastereoselective synthesis supported by quantum chemical (density functional theory) calculations. The fully aromatic [11]helicene was studied in detail including the measurement and theoretical calculation of its racemization barrier and its organization on the InSb (001) surface by STM. This research provides a strategy for the synthesis of long helical aromatics that inherently comprise 2 possible channels for charge transport: Along a ...-conjugated pathway and across an intramolecularly ...-... stacked aromatic scaffold. (ProQuest: ... denotes formulae/symbols omitted.)

关键词： alkyne cycloisomerization DFT calculations nonracemic compounds STM imaging helicene

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Charged Black Holes with Massive Scalar Field

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AIP Conference Proceedings 2009年第1期1186卷 166-172页

作者： D. Georgieva I. Stefanov M. Todorov S. Yazadjiev aFaculty of Applied Mathematics and Computer Science Technical University of Sofia 8 Kliment Ohridski Blvd. 1000 Sofia Bulgaria bDepartment of Applied Physics Technical University of Sofia 8 Kliment Ohridski Blvd. 1000 Sofia Bulgaria cDepartment of Theoretical Physics Faculty of Physics St.Kliment Ohridski University of Sofia 5 James Bourchier Blvd. 1164 Sofia Bulgaria

In the present work static and spherically symmetric magnetically charged black holes coupled to Euler‐Heisenberg type non‐linear electrodynamics in the scalar‐tensor theories of gravity with massive scalar field are investigated numerically. For the numerical solving of the corresponding boundary‐value problem with free boundary the Continuous Analogue of Newton Method is used. As a result of the numerical experiments some general properties of the solutions were found.

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Adapted list coloring of planar graphs

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Journal of Graph Theory 2009年第2期62卷 127-138页

作者： Esperet, Louis Montassier, Mickaël Zhu, Xuding Department of Applied Mathematics Faculty of Mathematics and Physics Institute for Theoretical Computer Science Prague Czech Republic Labri Université Bordeaux 1 Talence Cedex France Department of Applied Mathematics National Sun Yat-Sen University Kaohsiung Taiwan National Center for Theoretical Sciences Taiwan

Given an edge coloring F of a graph G, a vertex coloring of G is adapted to F if no color appears at the same time on an edge and on its two endpoints. If for some integer k, a graph G is such that given any list assignment L to the vertices of G, with |L(v)| ≥ k for all v, and any edge coloring F of G, G admits a coloring c adapted to F where c(v) ∈ L(v) for all v, then G is said to be adaptably k-choosable. In this note, we prove that K 5-minor-free graphs are adaptably 4-choosable, which implies that planar graphs are adaptably 4-colorable and answers a question of Hell and Zhu. We also prove that triangle-free planar graphs are adaptably 3-choosable and give negative results on planar graphs without 4-cycle, planar graphs without 5-cycle, and planar graphs without triangles at distance t, for any t0. © 2009 Wiley Periodicals, Inc.

关键词： Coloring

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Mathematical Modeling of Soliton‐like Solutions in the Scalar‐tensor Theories of Gravity

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AIP Conference Proceedings 2009年第1期1186卷 173-179页

作者： I. Zh. Stefanov D. Georgieva S. Yazadjiev M. Todorov aDept. of Applied Physics Technical University of Sofia 8 Kliment Ohridski Blvd. 1000 Sofia Bulgaria bFaculty of Applied Mathematics and Computer Science Technical University of Sofia 8 Kliment Ohridski Blvd. 1000 Sofia Bulgaria cSt.Kliment Ohridski University of Sofia Faculty of Physics Department of Theoretical Physics 5 J. Bourchier Blvd. 1126 Sofia Bulgaria

In the present, work we find new numerical solutions describing soliton‐like objects coupled to non‐linear electrodynamics in the scalar‐tensor theories of gravity. Approximate solutions have been also obtained and a comparison to the numerical results has been made. The non‐existence of black holes for the specific choice of lagrangian of the nonlinear electrodynamics has been also proved.

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Properties of a copolymer based on N-vinylcarbazole and 1,3,4-triphenyl-6-vinyl-1H-pyrazol[3,4-B]quinoline applied in electroluminescent devices

Properties of a copolymer based on N-vinylcarbazole and 1,3,...

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ICTON Mediterranean Winter Conference

作者： Jacek Niziol Ewa Gondek Pawel Armatys Monika Pokladko Pawel Szlachcic Andrzej Danel Jerzy Sanetra Faculty of Physics and Applied Computer Science AGH University of Science and Technology Krakow Poland Institute of Physics Cracow University of Technology Krakow Poland Department of Chemistry Agricultural University Krakow Poland Department of Chemistry Agricultural University of Krakow Balicka 122 31-149 Poland

The purpose of this work was synthesis of a new copolymer consisting of poly(N-vinylcarbazole) and pyrazoloquinoline based dye, suitable to provide electroluminescence in the wavelength range corresponding to the blue. The obtained material was tested in a simple, single layer electroluminescent device. It were studied both its electronic and optical performances. It was found that the maximum of electroluminescence spectrum can be tuned within the wavelength of 450 nm and 490 nm (what reads in terms of colours as the blue and the cyan) by simple variation of the dye content.

关键词： Electroluminescent devices Organic light emitting diodes Electroluminescence Nuclear magnetic resonance Methanol physics Chemical technology Organic electronics Electrodes NIST

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Numerical Study of Linear Stability of Scalar‐tensor Born‐Infeld Black Holes

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AIP Conference Proceedings 2009年第1期1186卷 159-165页

作者： D. Doneva S. Yazadjiev M. Todorov I. Stefanov aDepartment of Astronomy Faculty of Physics St.Kliment Ohridski University of Sofia 5 James Bourchier Blvd. 1164 Sofia Bulgaria bDepartment of Theoretical Physics Faculty of Physics St.Kliment Ohridski University of Sofia 5 James Bourchier Blvd. 1164 Sofia Bulgaria cFaculty of Applied Mathematics and Computer Science Technical University of Sofia 8 Kliment Ohridski Blvd. 1000 Sofia Bulgaria dDepartment of Applied Physics Technical University of Sofia 8 Kliment Ohridski Blvd. 1000 Sofia Bulgaria

Phases of scalar‐tensor black holes coupled to non‐linear electrodynamics where recently obtained and thermodynamical analysis of the obtained solutions was performed. Our task is to study numerically the linear stability of the solutions which has trivial scalar field. The obtained singular Sturm‐Liouville problem is solved with a modifications of the shooting method. Results are obtained and they are in a good agreement with the predictions of the thermodynamical analysis.

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X-ray grazing incidence technique-corrections in residual stress measurement-a review

X-ray grazing incidence technique-corrections in residual st...

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作者： Wroński, S. Wierzbanowski, K. Baczmański, A. Lodini, A. Braham, Ch. Seiler, W. Faculty of Physics and Applied Computer Sciences AGH University of Science and Technology al. Mickiewicza 30 30-059 Kraków Poland LACM Universit´ de Reims Champagne Ardenne 9 Bd. de la Paix 51100 Reims France LIM Ecole Nationale Suṕrieure d'Arts et &#7742tiers 151 Bd. de l'Hopital 75013 Paris France

Using X-ray grazing incidence diffraction (GID) it is possible to perform a nondestructive analysis of the heterogeneous stress field for different volumes below the surface of the sample. The stress can be measured at very small depths, of the order of a few μm. The penetration depth of radiation is almost constant in a wide 2θ range for a given incidence angle α. It can be easily changed by an appropriate selection of α angle (or also by using a different type of radiation). There are, however, some factors which have to be corrected in this technique. The most important is the refraction of X-ray wave: it changes the wavelength and direction of the beam. Both effects modify a pick position. A corresponding correction was calculated and tested on ferrite powder and on 316L austenite stainless steel sample. © 2009 International Centre for Diffraction Data.

关键词： Residual stresses

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Wave packet dynamics in semiconductor quantum rings of finite width

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Physical Review B 2009年第12期80卷 125331-125331页

作者： Andrey Chaves G. A. Farias F. M. Peeters B. Szafran Departamento de Física Universidade Federal do Ceará Caixa Postal 6030 Campus do Pici 60455-900 Fortaleza Ceará Brazil Department of Physics University of Antwerp Groenenborgerlaan 171 B-2020 Antwerp Belgium Faculty of Physics and Applied Computer Science AGH University of Science and Technology al. Mickiewicza 30 30-059 Kraków Poland

The time evolution of a wave packet injected into a semiconductor quantum ring is investigated in order to obtain the transmission and reflection probabilities. Within the effective-mass approximation, the time-dependent Schrödinger equation is solved for a system with nonzero width of the ring and leads and finite potential-barrier heights, where we include smooth lead-ring connections. In the absence of a magnetic field, an analysis of the projection of the wave function over the different subband states shows that when the injected wave packet is within a single subband, the junction can scatter this wave packet into different subbands but remarkably at the second junction the wave packet is scattered back into the subband state of the incoming wave packet. If a magnetic field is applied perpendicularly to the ring plane, transmission and reflection probabilities exhibit Aharonov-Bohm (AB) oscillations and the outgoing electrons may end up in different subband states from those of the incoming electrons. Localized impurities, placed in the ring arms, influence the AB oscillation period and amplitude. For a single impurity or potential barrier of sufficiently strong strength, the period of the AB oscillations is halved while for two impurities localized in diametrically opposite points of the ring, the original AB period is recovered. A theoretical investigation of the confined states and time evolution of wave packets in T wires is also made, where a comparison between this system and the lead-ring junction is drawn.

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Fe 57 Mössbauer effect studies of Dy(Fe 0.7− x Ni x Co 0.3 ) 2 intermetallics

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Journal of Alloys and Compounds 2009年第1-2期467卷 72-77页

作者： A. Stoch P. Guzdek P. Stoch J. Pszczoła J. Suwalski Institute of Electron Technology 30-701 Kraków ul.Zabłocie 39 Poland Faculty of Physics and Applied Computer Science AGH Al. Mickiewicza 30 30-059 Kraków Poland Institute of Atomic Energy 05-400 Świerk-Otwock Poland Faculty of Material Science and Ceramics AGH Al. Mickiewicza 30 30-059 Kraków Poland

A consequence of Fe/Ni substitution in the intermetallics Dy(Fe 0.7− x Ni x Co 0.3 ) 2 was tested in this paper. Fe 57 Mössbauer effect measurements for the intermetallic system were carried out at 4.2 K. The obtained hyperfine interaction data are presented. The magnetic hyperfine field as well as the Curie temperature is strongly reduced with a composition parameter x . Band structure calculations using the Full-Potential Linearized Augmented Plane Waves (FLAPW) method were performed. The experimentally determined magnetic hyperfine field correlates linearly with the weighted magnetic moment calculated per transition metal atom and correlates linearly with the average splitting energy between 3d subbands. The Curie temperature changes in an approximate linear fashion with the squared magnetic hyperfine field or with the calculated squared splitting energy between 3d subbands.

关键词： 61.10.Nz 71.20.Be 71.20.Eh 71.20.Lp 72.15.Eb 75.50.Gg 76.30.Kg Intermetallics Fe 57 Mössbauer effect Hyperfine interactions Magnetic hyperfine field Curie temperature Band structure FLAPW calculations Magnetic moments

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