Endurance limit of polyethylene during cyclic loading under conditions of a plane stressed state

Conclusions The effect of the asymmetry of the loading cycle on the fatigue strength of HDPE subjected to biaxial tension has been studied. An increase in the acuteness of the cycle leads to an increase in the durability of the material. Under conditions of cyclic loading, the material became embrittled as the duration of the experiment was extended. The effect of various different ratios between the principal stresses on the fatigue strength of HDPE has been investigated. It has been shown that the form of the isochronous boundary curves depends on the duration of the experiment. It was established that the mechanism of HDPE fracture changes depended on the duration of the loading. The accumulation of defects, when an experiment was of average or longer duration, built up at a greater rate than would have been predicted by a linear rule for summation.M. I. Kalinin Leningrad Polytechnic Institute. The "Plastpolimer" Okhtinsk Scientific Manufacturing Association, Leningrad. Translated from Mekhanika Polimerov, No. 1, pp. 35–40, January–February, 1977.     

Effect of diffusion and fluctuations in the nonequilibrium charge carrier density on the angular distribution of the output intensity for injection lasers based on an InAsSb/InAsSbP heterostructure

We have used numerical modeling to study the effect of diffusion and fluctuations in the nonequilibrium carrier density in the active layer of injection lasers based on an InAsSb/InAsSbP heterostructure on the angular distribution of the output intensity. We show that diffusion smoothes out the nonequilibrium carrier distribution in the active layer, and the fundamental lasing mode is stable over a much broader range of stripe contact widths. At the same time, diffusional processes can lead to formation of local regions with a jump in the density of nonequilibrium charge carriers, fluctuations in which can act as a source of instability for the fundamental lasing mode. Analysis of the numerical modeling results gives qualitative agreement with experimental data on the dependence of the angular distribution of the output radiation for different stripe contact widths.     

Synthesis of carbon planar structures with specified properties

A new method is proposed that allows an integrated technology to be used for the synthesis of carbon planar structures with predetermined properties. The method is based on the avalanche annealing of amorphous short-period superlattices. The synthesized samples are investigated by Raman spectroscopy and photoluminescence. The possibility of synthesizing carbon layers with diamond-like, graphite-like, graphene, or other structures is demonstrated experimentally using the example of a C/SiC superlattice.     

Thermoelectric coefficient in nanoisland metallic films

We study the thermoelectric properties of island metal films on a dielectric substrate. Dependence of thermoelectric coefficient of metal films on their thickness with the dimensionless conductance $g>1$ and $g<1$ was investigated. Also, the thermopower dependence of island metal structures with $g<1$ on the chemical composition of nanostructures was studied. We found that regardless of tunneling or Drude character of conductivity, the value of the thermoelectric coefficient in island metal films is determined by the properties of film metal element.     

Diode laser spectroscopy using two modes of an InAsSb/InAsSbP laser near 3.6 μm

A new type of multimode semiconductor laser, based on InAsSb/InAsSbP heterostructures, is described. This continuous laser working in a broad range of temperatures (30–100 K) was tested using a closed-cycle He-cryostat and its quality was demonstrated using the laser spectroscopy of gases absorbing in the 2800 cm^-1 region. Two different laser modes were used to increase the spectral range. The spectral characteristics and tunability of the laser were explored as a function of heat-sink temperature and drive current with the aim of developing its use for high–resolution spectroscopy. The laser has potential applications in the field of chemistry, atmospheric research and the study of the kinetics of reactive species. Received: 18 October 1999 / Revised version: 10 May 2000 / Published online: 16 August 2000     

Projective Convex Combinations in C *-Algebras with the Unitary Factorization Property

Mathematical Notes -     

Fullerenes as passivating agents of the surfaces of semiconductor photo- and light-emitting diodes

A new pathway for passivation of the surface of infrared photodiodes and light-emitting diodes operating at room temperature in the spectral range of 2–5 μm by individual fullerene C₇₀ is proposed and its characteristics are studied. It is determined that during the passivation of photodiodes, dark current falls by 40% and resistance at zero bias increases by 24%; for light-emitting diodes, leaks fall by ∼20%, and resistance at zero bias increases by 45% and the intensity of emission of light-emitting diodes increases by ∼18% after the application of fullerene C₇₀.     

Luminescence and epr of electron-irradiated zinc oxide single crystals

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 52, No. 5, pp. 754–758, May, 1990.     

Heavy fullerenes for semiconducting photodiodes operating at 1.5–5.0 μm wavelengths

A new method for the passivation of the surface of infrared photodiodes operating at room temperature, spectral range 1.5–5.0 μm, by a mixture of higher fullerenes (h-f-mix) C₇₆ + C₇₈ + C₈₄ + C₉0 + … was suggested. The main service characteristics of photodiodes were studied. The passivation of photodiodes decreased their dark current by 14%. The Peltier effect was observed for the A³B⁵ semiconductor/h-f-mix heterojunction.