Optical properties of graphite-like carbon films

A model of the electronic structure of graphite-like carbon films, describing the semiconductor properties of this material, is presented. Spectra of optical constants of microcrystalline carbon films in the region λ = 0.4–8.0 μm were studied by the spectral ellipsometry and IR reflection methods. A number of distinctive features of the spectra, associated with both the appearance of C---C- and C---H_n-type bonds and direct energy gaps, were found. Analysis of the optical data using the proposed model makes possible a common interpretation of our results and literature data. Values of a parameter Θ, which is an averaged qualitative parameter of structural distortions within carbon microcrystallites as compared with crystalline graphite, are determined from comparison of theoretical results and experimental data.     

Structure and Certain Properties of Hot-Pressed Boron Carbide-Based Ceramic with Calcium-Silicon Additive

The influence which the composition of powder mixtures, the treatment conditions which the mixtures are subjected to, and the conditions under which the hot-pressed composite materials B₄C – (5-10 mass%) calcium-silicon are fabricated exert on the structure, nature of failure, and mechanical properties of these materials is investigated. Optimum properties are possessed by material containing 10 mass% of addition. It is shown that the structure, morphology, and dispersivity, as well as the nature of the distribution of the components that are added to the composite material (secondary phase) vary as the temperature of hot pressing changes. Maximal mechanical characteristics of the composite material (σ_bend = 560 MPa, K _1c = 4.7 MPa·m^1/2, HV = 37 GPa) are attained at hot-pressing temperatures in the range 2000-2100°C.     

Activation energy of electron-stimulated quenching of the photoluminescence of n-type porous silicon

The degradation of photoluminescence of porous silicon by kilovolt electrons and the mechanism and activation energy of this process have been investigated. Quantitative relations between the integral intensity of the photoluminescence and the irradiation dose and substrate temperature are obtained. The mechanism of the process is discussed and its activation energy is determined. Pis’ma Zh. Tekh. Fiz. 23, 44–50 (September 26, 1997)     

Dual-purpose technologies in view of diversification of the military-industrial complex of Russia

Current problems in scientific-information support of the process of diversification of the military-industrial complex (or defense-industrial complex, DIC) of Russia are considered, which can facilitate the effective usage of dual-purpose technologies in various civilian fields of the national economy. In this context, the program of the 7th Specialized Exhibition “Dual-Purpose Products and Technologies: DIC Diversification,” which was held in Moscow in October 2006, is analyzed.     

Simulation of auto-ignition of iso-octane and n-heptane in an internal combustion engine

A detailed kinetic mechanism is proposed for the oxidation of iso-octane, n-heptane, and mixtures of them in air (number of particles 43, number of reactions 284), which satisfactorily describes the distinctive features of low-temperature and high-temperature oxidation at an initial temperature of 1200 K, pressure of 15–40 absolute atmospheres or higher, and a fuel excess ratio of 0.5–2. The abbreviated mechanisms obtained to describe the auto-ignition of fuel with an octane number of 90 involve 27 particles (38 reactions) and 18 particles (22 reactions).N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, 117977. Translated from Fizika Goreniya i Vzyrva, Vol. 30, No. 6, pp. 15–25, November–December, 1994.     

Status of Work on the VÉPP-5 Injection Complex

The VÉPP-5 injection complex under construction at the Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences is a powerful source of intense electron and positron bunches at 510 MeV, which covers all needs of the electron–positron colliding beam setups currently operating and under construction at the Institute of Nuclear Physics. The complex includes a 285 MeV linear electron accelerator, a 510 MeV linear positron accelerator, and an accumulator–cooler with beam injection and ejection channels. Intense work on the design, assembly, and tuning of the linear electron accelerator has been conducted in the last 2 yr. As a result, by August 2002 the linear electron accelerator was put into operation with all standard subsystems. By this time, the isochronous achromatic turning of the electron beam, a system for converting electrons into positrons, and the first accelerating structure of the linear positron accelerator were assembled and put into operation. All this made it possible to accelerate the positron beam up to 75 MeV. Preliminary results of tests of the linear accelerators are presented.