Surface plasmon enhanced absorption and suppressed transmission in periodic arrays of graphene ribbons

Resonance diffraction in the periodic array of graphene micro-ribbons is theoretically studied following a recent experiment [L. Ju et al, Nature Nanotech. 6, 630 (2011)]. Systematic studies over a wide range of parameters are presented. It is shown that a much richer resonant picture would be observable for higher relaxation times of charge carriers: more resonances appear and transmission can be totally suppressed. The comparison with the absorption cross-section of a single ribbon shows that the resonant features of the periodic array are associated with leaky plasmonic modes. The longest-wavelength resonance provides the highest visibility of the transmission dip and has the strongest spectral shift and broadening with respect to the single-ribbon resonance, due to collective effects.Comment: 5 pages, 3 figure

Resonantly suppressed transmission and anomalously enhanced light absorption in ultrathin metal films

We study light diffraction in the periodically modulated ultrathin metal films both analytically and numerically. Without modulation these films are almost transparent. The periodicity results in the anomalous effects, such as suppression of the transmittance accompanied by a strong enhancement of the absorptivity and specular reflectivity, due to excitation of the surface plasmon polaritons. These phenomena are opposite to the widely known enhanced transparency of periodically modulated optically thick metal films. Our theoretical analysis can be a starting point for the experimental investigation of these intriguing phenomena.Comment: 4 pages, 5 figure

Giant volume magnetostriction in the Y 2

An investigation of the Y2Fe17 compound belonging to the class of intermetallic alloys of rare-earth and 3d-transition metals is presented. The magnetization, magnetostriction, and thermal expansion of the Y2Fe17 single crystal were studied. The forced magnetostriction and magnetostriction constants were investigated in the temperature range of the magnetic ordering close to the room temperature. The giant field induced volume magnetostriction was discovered in the room temperature region in the magnetic field up to 1.2 T. The contributions of both anisotropic single-ion and isotropic pair exchange interactions to the volume magnetostriction and magnetostriction constants were determined. The experimental results were interpreted within the framework of the Standard Theory of Magnetostriction and the Landau thermodynamic theory. It was found out that the giant values of the volume magnetostriction were caused by the strong dependence of the 3d-electron Coulomb charge repulsion on the deformations and width of the 3d-electron energy band

History of pediatric endoscopy in the Republic of Karelia

The article is dedicated to the 40th anniversary of the pediatric endoscopic service of the Republic of Karelia. In the introductory part of the article, the authors briefly describe the history of the appearance of endoscopy in the world, which dates back to 1881, when J. Mikulicz-Radecki designed and first used a rigid gastroscope in an adult patient, and then developed very slowly for a long time. Isolated attempts to use gastroscopy, bronchoscopy, and laparoscopy are described. For laparoscopy, a frontal reflector, electric lamps, mirrors were used, and later - the first cystoscopes and rectoscopes. In 1890-1930, there were only a few publications per decade devoted to the development of endoscopic technology. In the Republic of Karelia, the formation of the endoscopic service is associated with the formation of the Karelian Center for Pediatric Surgery. Gastroscopies were initially performed with rigid endoscopes and the main reasons for the appointment of such studies were injuries and burns of the esophagus. The first gastroscopy of a teenager was performed in March 1982, an artifact is presented - a photo of the conclusion of this study. The authors tell about the stages of the formation of the service in the Republic of Karelia. In pediatric practice, the most difficult contingent of patients are newborns and premature babies. Endoscopies for newborns have been performed since 1985. Intraluminal endoscopic interventions have been performed since 1989, and diagnostic laparoscopies have been performed since 1990. Since 1991, laparoscopic operations have been performed under visual control - 57 interventions were performed before the appearance of video resistance. We also recall the period of the economically difficult last decade of the twentieth century, when the development of the endoscopic service continued thanks to the supply of equipment from the twin city of Tubingen. With the advent of the video system, the endoscopic service has gradually developed to the modern level, at which the entire main range of endosurgical interventions is performed

Curve crossing in linear potential grids: the quasidegeneracy approximation

The quasidegeneracy approximation [V. A. Yurovsky, A. Ben-Reuven, P. S. Julienne, and Y. B. Band, J. Phys. B {\bf 32}, 1845 (1999)] is used here to evaluate transition amplitudes for the problem of curve crossing in linear potential grids involving two sets of parallel potentials. The approximation describes phenomena, such as counterintuitive transitions and saturation (incomplete population transfer), not predictable by the assumption of independent crossings. Also, a new kind of oscillations due to quantum interference (different from the well-known St\"uckelberg oscillations) is disclosed, and its nature discussed. The approximation can find applications in many fields of physics, where multistate curve crossing problems occur.Comment: LaTeX, 8 pages, 8 PostScript figures, uses REVTeX and psfig, submitted to Physical Review

Structure, optical, electrical and thermoelectric properties of solution-processed Li-doped NiO films grown by SILAR

The article presents a new facial synthesis of Li-doped NiO films (NiO:Li) via an easy and cost-effective method Successive Ionic Layer Adsorption and Reaction (SILAR) with the processing of the obtained NiO films in a lithium-containing aqueous solution for their transformation after annealing into NiO:Li layers. Comparative analysis of crystal structure, optical, electrical and thermoelectric properties of the obtained NiO and NiO:Li 420-1050 nm thick films have reveiled a cubic rock-salt NiO structure, at that, NiO:Li samples are nanocrystalline single phased Li-NiO solid solutions. The fabricated NiO and NiO:Li films are p-type semiconductors with activation energy Ea = 0.1 eV and Ea = 0.25‒0.31 eV, respectively. The obtained in-plane Seebeck coefficients Z are in the range 0.20–0.33 mV/К. Notwithstanding the fact that the maximum values of the thermoelectric power factors P=2.2 μW/K2·m, are rather small, they were achieved if the hot end of the NiO:Li film was heated only to 115 °C. Thus, the produced in this work new low cost thermoelectric thin film material is suitable for a production of electrical energy for low-power devices due to absorption of low-potential heat