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81.
The paper provides a combinatorial method to decide when the space of local systems with nonvanishing first cohomology on the complement to an arrangement of lines in a complex projective plane has as an irreducible component a subgroup of positive dimension. Partial classification of arrangements having such a component of positive dimension and a comparison theorem for cohomology of Orlik–Solomon algebra and cohomology of local systems are given. The methods are based on Vinberg–Kac classification of generalized Cartan matrices and study of pencils of algebraic curves defined by mentioned positive dimensional components. 相似文献
82.
83.
Viktor F. Ivanov Oxana L. Gribkova Olga D. Omelchenko Alexander A. Nekrasov Vladimir A. Tverskoy Anatoly V. Vannikov 《Journal of Solid State Electrochemistry》2010,14(11):2011-2019
Various polyaniline (PANI) interpolymer complexes with polyacids in the form of molecular solutions were synthesized by chemical
oxidative polymerization of aniline in the presence of water-soluble poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) (flexible
backbone), poly-p,p′-(2,2′-disulfoacid)-diphenylene-terephthalamide (t-PASA, rigid backbone), and their mixtures in different ratios. The complexes
were characterized by UV-Vis-near infrared spectroscopy in solutions; also, the films’ drop-casts from these solutions were
investigated by cyclic voltammetry, spectroelectrochemical, direct current (DC) conductivity, and atomic force microscopy
(AFM) measurements. It was shown that the nature of polyacid affects the shape of spectra and the dynamics of their changes.
The character of spectral changes during the matrix synthesis of PANI in the presence of mixtures of the rigid-chain and flexible-chain
matrixes and the study of spectral properties of the obtained PANI solutions demonstrates the existence of the rigid-matrix
domination effect in the process of formation of PANI interpolymer complexes. Spectral properties of the obtained PANI complexes
with the mixtures of flexible-chain and rigid-chain polyacids of different ratios (3:1, 1:1, 1:3, and 1:6) are very similar
to those ones for the complex with rigid-chain t-PASA. At the same time, there is a correlation between the electrical conductivity
and morphology of the films of PANI complexes and their composition, the conductivity passing through a minimum for the complexes
with the polyacid mixtures (6:1, 3:1, and 1:1). 相似文献
84.
Levina EV Kalinovsky AI Dmitrenok PS Martyyas EA Stonik VA 《Natural product communications》2010,5(11):1737-1742
New steroid glycosides, hylodoside A (1) and novaeguinoside Y (2), along with previously known polyhydroxylated steroids (3-7) were isolated from the ethanolic extracts of the starfish Leptasterias hylodes reticulata and Culcita novaeguineae (juvenile). The structures have been elucidated using 1D and 2D NMR spectra (1H, 13C, DEPT, COSY-45, 1D-TOCSY, HSQCGP, ROESY, HSQC and HMBCGP) and mass spectrometry. Compound 3 was shown to inhibit the growth of Staphylococcus aureus up to 10% from the control at a concentration of 1 mg/mL. Steroids 1, 2 and 5 showed moderate hemolytic activity in the mouse erythrocytes assay. Compounds 3, 4 and 6 displayed pH-depended hemolytic properties. 相似文献
85.
García-Meca C Hurtado J Martí J Martínez A Dickson W Zayats AV 《Physical review letters》2011,106(6):067402
We experimentally demonstrate a low-loss multilayered metamaterial exhibiting a double-negative refractive index in the visible spectral range. To this end, we exploit a second-order magnetic resonance of the so-called fishnet structure. The low-loss nature of the employed magnetic resonance, together with the effect of the interacting adjacent layers, results in a figure of merit as high as 3.34. A wide spectral range of negative index is achieved, covering the wavelength region between 620 and 806 nm with only two different designs. 相似文献
86.
Anatoly F. Nastoyashchiy 《Journal of Russian Laser Research》2011,32(3):238-246
We propose a simple target in the form of a miniature torus, in which the heavy shell is used to confine the plasma spread,
for a solution of the laser-fusion problem. We achieve a significant decrease of heat losses using an external magnetic field
and/or as a result of a self-sustaining magnetic field that is generated in the plasma. We formulate the conditions and determine
the energy of the laser pulse (or of a beam of fast charged particles) required to ignite a thermonuclear DD reaction and
obtain a positive energy yield. We show that the stopping range of α-particles does not exceed the small radius of the torus
within a broad range of the plasma and magnetic-field parameters. 相似文献
87.
We present a comprehensive numerical analysis of the guiding of a photonic signal in the form of a strongly confined asymmetric surface plasmon polariton (SPP) mode along metallic nanowire waveguides. The proposed approach provides extremely high localization of the SPP mode, nanoscale integration density, and a feasible technological platform. The waveguide performance was studied over a broad range of subwavelength cross sections at a telecommunication wavelength. It was optimized using a conventional figure of merit for data transfer along a straight waveguide and an all-inclusive figure of merit has been introduced. 相似文献
88.
Anatoly Tur 《Physica D: Nonlinear Phenomena》2011,240(13):1069-1079
In this work we present a new class of exact stationary solutions for two-dimensional (2D) Euler equations. Unlike already known solutions, the new ones contain complex singularities. We consider point singularities which have a vector field index greater than 1 as complex. For example, the dipole singularity is complex because its index is equal to 2. We present in explicit form a large class of exact localized stationary solutions for 2D Euler equations with a singularity whose index is equal to 3. The solutions obtained are expressed in terms of elementary functions. These solutions represent a complex singularity point surrounded by a vortex satellite structure. We also discuss the motion equation of singularities and conditions for singularity point stationarity which provide the stationarity of the complex vortex configuration. 相似文献
89.
General integral relations expressing the droplet radius and time of the droplet nonstationary growth as nonlinear functions of solution concentration in the droplet have been derived. These relations are valid for a supercritical droplet (i.e., sufficiently large droplet, for which the Laplace pressure effect on the concentration at saturation of vapors is negligible) isothermally growing via stationary diffusion in the mixture of two condensing vapors and an incondensable carrier gas. The initial composition in the droplet may be arbitrary and partial molecular volumes of components are not fixed. Explicit analytical relations have been found for droplet composition and the droplet size as functions of time at small deviations from the stationary concentration in the growing droplet. These relations show that the assumption of the steady droplet growth rate is not valid for non-small deviations from the stationary concentration. Some illustrations of the general nonlinear theory have been done in situation when solution in the droplet can be considered ideal. 相似文献
90.
Natalia M. Markovich 《Extremes》2014,17(1):97-125
In practice it is important to evaluate the impact of clusters of extreme observations caused by the dependence in time series. The clusters contain consecutive exceedances of time series over a threshold separated by return intervals with consecutive non-exceedances. We derive asymptotically equal distributions of the number of inter-arrival times between events of interest arising both between two consecutive exceedances of a stationary process $\{R_n:n\ge 1\}$ and between two consecutive non-exceedances. It is found that the distributions are geometric like and corrupted by the extremal index. It is derived that the limit distribution tail of the duration of clusters that is defined as a sum of the random number of the weakly dependent regularly varying inter-arrival times with tail index $0<\alpha <2$ is bounded by the tail of stable distribution. The inferences are valid when the threshold is taken as a sufficiently high quantile of the underlying process $\{R_{n}\}$ . 相似文献