Engineering the activity and lifetime of heterogeneous catalysts for carbon nanotube growth via substrate ion beam bombardment.

We demonstrate that argon ion bombardment of single crystal sapphire leads to the creation of substrates that support the growth of vertically aligned carbon nanotubes from iron catalysts with a density, height, and quality equivalent to those grown on conventional, disordered alumina supports. We quantify the evolution of the catalyst using a range of surface characterization techniques and demonstrate the ability to engineer and pattern the catalyst support through control of ion beam bombardment parameters.

[Problems and prospects of infectious diseases and HIV-infected military personnel register organization].

An analysis of regulatory documents of the Ministry of Healthcare and the Ministry of Defence of the Russian Federation related to HIV/AIDS prevention was carried out. The current system of HIV/AIDS detection and registration among military and civil personnel was assessed. Problems and prospects of scientific-and-research laboratory (the register of infectious disease pathology and HIV-infected military personnel) of Scientific-and-research centre at the Kirov Military medical academy were discussed. It is proposed that the main direction of the laboratory activity will be the restoration of up-to-date records of military personnel with HIV/AIDS. This activity will provide the necessary information to responsible specialists of the Main state sanitary and epidemiological surveillance centre and the Main military medical department of the Ministry of Defence of the Russian Federation for the sanitary and epidemiological surveillance for purposeful and economically feasible management decisions in the field of military personnel infection diseases prevention.

Unraveling nanotubes: field emission from an atomic wire.

Field emission of electrons from individually mounted carbon nanotubes has been found to be dramatically enhanced when the nanotube tips are opened by laser evaporation or oxidative etching. Emission currents of 0.1 to 1 microampere were readily obtained at room temperature with bias voltages of less than 80 volts. The emitting structures are concluded to be linear chains of carbon atoms, Cn, (n = 10 to 100), pulled out from the open edges of the graphene wall layers of the nanotube by the force of the electric field, in a process that resembles unraveling the sleeve of a sweater.

Growth and sintering of fullerene nanotubes.

Carbon nanotubes produced in arcs have been found to have the form of multiwalled fullerenes, at least over short lengths. Sintering of the tubes to each other is the predominant source of defects that limit the utility of these otherwise perfect fullerene structures. The use of a water-cooled copper cathode minimized such defects, permitting nanotubes longer than 40 micrometers to be attached to macroscopic electrodes and extracted from the bulk deposit. A detailed mechanism that features the high electric field at (and field-emission from) open nanotube tips exposed to the arc plasma, and consequent positive feedback effects from the neutral gas and plasma, is proposed for tube growth in such arcs.

[Algorithms of color differentiation using reactions of logarithmic receptors]. / Algoritmy tsvetorazlicheniia ob''ektov po reaktsiiam logarifmicheskikh priemnikov.

Ways are described for calculating by the reactions of logarithmic photoreceptors the functions invariant to changes of illumination of a monotonously coloured non-flat object. Conditions for applications of the proposed algorithms to j-chromatic systems of colour vision are discussed.

[Mono-ocular color differentiation of three-dimensional objects in different illumination conditions]. / Monokuliarnoe tsvetorazlichenie ob''emnykh predmetov pri raznykh usloviiakh osveshcheniia.

General methods are described for calculating some functions of spectral parameters of illumination sources invariant to illumination changes within the limits of uniformly colored non-plane surface. Relation is shown between the number of linearly-independent acceptors of the system necessary for plotting such invariant and the complexity degree of illumination of the picture observed.

[A model of constant color perception for continuous spectral functions]. / Model' konstantnosti tsvetovospriiatiia dlia sluchaia nepreryvnykh spektral'nykh funktsii.

A trichromatic model is proposed of constant pattern of colour perception (MCCP) for scenes with a single illumination source. In MCCP functions of the source emission, surface reflection, photoacceptor sensitivity are approximated by the normal distribution curves. MCCP characteristics "colour tone", "cleanness", and "lightness" organize its output colour metric by the human's pattern, and in a wide range of spectral composition of illumination they are invariant under these changes. Special colorimetric regime of MCCP work which estimates the colour of visual stimulus permits a comparison between the efficiencies of two proposed algorithms of visual information processing for MCCP.

[Trichromatic model of the constant perception of the color of objects]. / Trikhromaticheskaia model' konstant vospriiatiia okraski ob'ektov.

A description is presented of a trichromatic model of colour constancy (MCC) of objects with concavities: folds, holes and so on. MCC involves the system of algorithmically independent processing blocks of the image heterarchically interacting and creating at its outlet a triparametric estimation of surface reflectance of each object of the picture. This estimation little depends on changes in the illumination colour. Results are presented and discussed of a computer experiment with MCC simulating the scene in which a plane with differently coloured regions and a conic hole in each are illuminated with a single chromatic light source.

[Perception of color and volumetric shape of objects]. / Ob uznavanii okraski i ob''emnoi formy predmetov

The problem of recognition of coloration of volume objects, illuminated simultaneously with bright point ans weak diffuse sources (having arbirary and previously unknown spectra) is considered. A mathematical model, in which a process of recognition of coloration is accompanied by determining orientations of surface elements relatively the point source is described. The information on orientation allows in many cases to calculate the volume shape of objects of the external world form their monocular ""retinal"" image.

[Physiologic mechanisms of the constancy of color perception]. / Fiziologicheskie mekhanizmy konstantnosti tsvetovospriiatiia

The color constancy is the ability to recognize correctly the colours of the objects under different illuminations. For this purpose the visual system must identify the character of illumination and estimate the colour of the object, using the light reflected from this object according to the spectrum of illumination. The behavioral experiments with fishes showed that they possess the colour constancy. The electrophysiological studies on colour-coding ganglion cells showed that the simplest mechanisms of estimating the colours of objects according to illumination exist at the retinal level. The presence of colour vision facilitates the recognition of the volume form of the objects. The generally accepted view on the place and role of colour vision in the general function of the visual system of animals has to be changed on the basis of these facts.

Crystalline Ropes of Metallic Carbon Nanotubes

Fullerene single-wall nanotubes (SWNTs) were produced in yields of more than 70 percent by condensation of a laser-vaporized carbon-nickel-cobalt mixture at 1200degreesC. X-ray diffraction and electron microscopy showed that these SWNTs are nearly uniform in diameter and that they self-organize into "ropes," which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms. The x-ray form factor is consistent with that of uniformly charged cylinders 13.8 +/- 0.2 angstroms in diameter. The ropes were metallic, with a single-rope resistivity of <10(-4) ohm-centimeters at 300 kelvin. The uniformity of SWNT diameter is attributed to the efficient annealing of an initial fullerene tubelet kept open by a few metal atoms; the optimum diameter is determined by competition between the strain energy of curvature of the graphene sheet and the dangling-bond energy of the open edge, where growth occurs. These factors strongly favor the metallic (10,10) tube with C5v symmetry and an open edge stabilized by triple bonds.