Gasdynamic analysis of a pneumatic line launcher

A solution to the problem of motion of a projectile in the bore of a pneumatic line launcher equipped with a fast-acting valve of large clear opening is obtained. The results are represented in the user-friendly graphical form and include a variety of the gasdynamic and design parameters of the launcher that influence the projectile velocity. The calculated data are in good agreement with data of multiparametric experiments.     

Channels in rotating liquids for conducting discharges, transporting currents and particle and radiation fluxes, and lowering breakdown thresholds

The formation of gas channels in rotating liquids is investigated and the application of such channels as capillaries for high-power discharges in x-ray lasers, for transporting particle and radiation fluxes, and lowering breakdown thresholds (including with the use of metal fillings), for structural systems for microwave generation and particle acceleration, and for photochemical and shock action on a liquid, and so on, is discussed. It is noted that tubular active elements and samples can be fabricated by solidification and crystallization during rotation. Pis’ma Zh. éksp. Teor. Fiz. 65, No. 3, 291–294 (10 February 1997)     

Solar modulation of cosmic deuteron fluxes in the PAMELA experiment

The preliminary results from measurements of deuteron fluxes in galactic cosmic rays (GCR) in the vicinity of the Earth in 2006–2009 are presented. The results are obtained by analyzing data from the PAMELA experiment aboard the Resurs DK-1 satellite. High-precision detection instruments provided an opportunity to identify GCR deuterons and measure their spectrum in the energy interval of 90–650MeV/nucleon. Spectra averaged over six-month intervals from the summer of 2006 to the summer of 2009 (the solar activity minimum) are presented. The influence of solar modulation on the observed spectrum is clearly seen in the results.     

Trapped Positrons and Electrons in the Inner Radiation Belt According to Data of the PAMELA Experiment

Measurements of secondary-electron and secondary-positron fluxes below the geomagnetic cutoff in near-Earth space were performed by means of the PAMELA magnetic spectrometer installed on board the Resurs-DK1 satellite launched on June 15, 2006, in an elliptical orbit of inclination 70° and altitude 350 to 600 km. This spectrometer permits measuring the fluxes of electrons and positrons over a wide energy range, as well as determining their spatial distributions to a precision of about 2°. A calculation of particle trajectories in the geomagnetic field makes it possible to separate electrons and positrons originating from cosmic-ray interactions in the Earth’s magnetosphere. The spatial distributions of quasitrapped, trapped, and short-lived albedo positrons and electrons of energy above 70 MeV in the radiation belt were analyzed. The ratio of the electron-to-positron fluxes and the energy spectra of the electrons and positrons in question are indicative of different productionmechanisms for stably trapped and quasitrapped secondary particles.     

Valence states and coordination of titanium ions in beryl crystals

The valence states and coordination of titanium ions in beryl crystals grown from flux and by gastransport reactions have been studied by the methods of electron paramagnetic resonance (EPR) and optical spectroscopy. The parameters of the EPR spectra for Ti³⁺ in the Al³⁺ and Si⁴⁺ sites are determined. It is found that at concentrations exceeding 0.1–0.15 wt %, the EPR-spectra have additional lines due to exchange-bonded pairs of Ti³⁺ ions. It is shown that the two-humped absorption band with the maxima at 495 (π), 545 (π), and 495 (π) nm are formed due to Ti³⁺ ions located in the octahedral position.     

Comment on “Plasmonic nanoparticle monomers and dimers: from nanoantennas to chiral metamaterials” by Chigrin et al. in Appl Phys B (2011) 105:81–97

Chigrin et al. (Appl Phys B 105:81, 2011) have recently presented a general direct solution of the integral equation for the electric field inside the scatterer, which does not require inversion of integral operator or, equivalently, solution of large system of linear equations. This comment points out that the rigorous applicability of the considered derivation is limited to ellipsoids much smaller than the wavelength.     

Scientific tasks and present status of the GAMMA-400 project

The GAMMA-400 telescope is designed to investigate discrete high-energy gamma-ray sources in the energy range of 0.1–3000 GeV, to measure the energy spectra of galactic and extragalactic diffuse gammaray emissions, and to study gamma-ray bursts and gamma-ray emissions from an active Sun. The gamma-ray telescope has an angular resolution of ～0.01°, an energy resolution of ～1%, and a proton rejection factor of ～10⁶. Its special assignment is to measure fluxes of gamma rays, electrons, and positrons that could be associated with the annihilation or decay of dark matter particles.     

Geometric minimality conditions for systems of exponentials inL p [−π, π]

A proof is given of the stability theorem for minimal systems of exponentialse(Λ) = {e ^iλx }λ∈Λ inL _p [−π, π], where Λ ⊂ ℂ is a discrete subset. Geometric minimality conditions for such systems are obtained. Translated fromMatematicheskie Zametki, Vol. 58, No. 5, pp. 773–777, November, 1995. I wish to express gratitude to A. A. Shkalikov, who posed the problem and paid constant attention to this work.