Nanocomposite Materials for Cell Growth

We propose a development of carbon nanotube (CNT)/albumin nanocomposite for 2D and 3D tissue organization by cell growth. The adhesion and proliferation for neuroblastoma and fibroblast cells have been investigated on films based on CNT/bovine serum albumin (BSA) nanocomposite. Single-walled car-bon nanotube (SWNT)/BSA composites can be used as a substrate for cell growth of different kind. The layers of nanocomposite properties growing method based on laser radiation action. Investigations of sta-bility, an adhesion and internal structure of layers were performed. Stabilizing properties of the described laser method of manufacture (laser nanoforming) of layers may be associated with the ability to obtain nanotube frame work in composite structure under action of electric field of directed laser radiation. The presence of a such frame creates the conditions for self-assembly of biomedical tissues. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3545

On the CP-odd Nucleon Potential

The CP-odd nucleon potential for different models of CP violation in the one meson exchange approximation is studied. It is shown that the main contribution is due to the $\pi$-meson exchange which leads to a simple one parameter CP-odd nucleon potential.Comment: 12 pages, RevTex, UM-P-92/114, OZ-92/3

Models of electron transport in single layer graphene

The main features of the conductivity of doped single layer graphene are analyzed, and models for different scattering mechanisms are presented.Comment: 15 pages. Submitted to the Proceedings of the ULTI symposium on Quantum Phenomena and Devices at Low Temperatures, Espoo, Finland, to be published in the Journ. of Low. Temp. Phy

Revised data on γ-families observed in X-ray emulsion chambers of the Experiment PAMIR

Recently essential efforts were made to improve measurement routine with X-ray films exposed in the X-ray emulsion chambers at the Pamirs. Analysis of X-ray emulsion response upon recorded events show that γ-family energy and intensity in early publications were over estimated. The main physical results of the new analysis are presented

Measurements of spin rotation parameter A in pion-proton elastic scattering at 1.62 GeV/c

The ITEP-PNPI collaboration presents the results of the measurements of the spin rotation parameter A in the elastic scattering of positive and negative pions on protons at P_beam = 1.62 GeV/c. The setup included a longitudinally-polarized proton target with superconductive magnet, multiwire spark chambers and a carbon polarimeter with thick filter. Results are compared to the predictions of partial wave analyses. The experiment was performed at the ITEP proton synchrotron, Moscow.Comment: 7 pages, 3 figures. To be published in Phys. Lett.

Exact eigenstate analysis of finite-frequency conductivity in graphene

We employ the exact eigenstate basis formalism to study electrical conductivity in graphene, in the presence of short-range diagonal disorder and inter-valley scattering. We find that for disorder strength, $W \ge$ 5, the density of states is flat. We, then, make connection, using the MRG approach, with the work of Abrahams \textit{et al.} and find a very good agreement for disorder strength, $W$ = 5. For low disorder strength, $W$ = 2, we plot the energy-resolved current matrix elements squared for different locations of the Fermi energy from the band centre. We find that the states close to the band centre are more extended and falls of nearly as $1/E_l^{2}$ as we move away from the band centre. Further studies of current matrix elements versus disorder strength suggests a cross-over from weakly localized to a very weakly localized system. We calculate conductivity using Kubo Greenwood formula and show that, for low disorder strength, conductivity is in a good qualitative agreement with the experiments, even for the on-site disorder. The intensity plots of the eigenstates also reveal clear signatures of puddle formation for very small carrier concentration. We also make comparison with square lattice and find that graphene is more easily localized when subject to disorder.Comment: 11 pages,15 figure

Development of a Momentum Determined Electron Beam in the 1 -45 GeV Range

A beam line for electrons with energies in the range of 1 to 45 GeV, low contamination of hadrons and muons and high intensity up to 10^6 per accelerator spill at 27 GeV was setup at U70 accelerator in Protvino, Russia. A beam tagging system based on drift chambers with 160 micron resolution was able to measure relative electron beam momentum precisely. The resolution sigma_p p was 0.13% at 45 GeV where multiple scattering is negligible. This test beam setup provided the possibility to study properties of lead tungstate crystals (PbWO_4) for the BTeV experiment at Fermilab.Comment: 12 pages, 8 figures; work done by the BTeV Electromagnetic Calorimeter grou

Structure and properties of W, Ta and W-Ta coatings deposited with the use of a gas-plasma source

W, Ta and W-Ta coatings were deposited by argon ion sputtering of targets made from appropriate metals using the gas plasma source. Mechanical properties of the obtained coatings were investigated by the methods of X-ray fluorescence analysis, scanning electron microscopy, X-ray diffraction analysis and nanoindentation. It has been shown that the coatings have a bcc structure with crystallite size from 16 to 30 nm. Single-component coatings have a columnar structure. Introduction of Ta (5…38%) in the W coating leads to the columnar growth suppression and formation of a condensate with more equiaxial elements. Coatings with such a structure possess the best mechanical properties (H/E-0.7…0.77).За допомогою джерела газової плазми, шляхом розпилення іонами аргону мішеней з відповідних металів отримані W, Ta і W-Ta-покриття. Методами рентгенофлюоресцентного аналізу, скануючої електронної мік-роскопії, рентгеноструктурного аналізу та наноіндентування вивчені: склад, структура, а також механічні властивості отриманих покриттів. Показано, що покриття володіють ОЦК-структурою з розміром ОКР від 16 до 30 нм. Однокомпонентні покриття володіють стовбчастою структурою. Введення до складу W-покриття Та (5…38 мас.%) призводить до припинення стовпчастого росту і формуванню конденсату з більш равновісними структурними елементами. Покриття з такою структурою володіють кращими механічними властивостями (Н/Е-0,7...0,77).С помощью источника газовой плазмы, путем распыления ионами аргона мишеней из соответствующих металлов получены W, Ta и W-Ta-покрытия. Методами рентгенофлюоресцентого анализа, сканирующей электронной микроскопии, рентгеноструктурного анализа и наноиндентирования изучены: состав, структура, а также механические свойства полученных покрытий. Показано, что покрытия обладают ОЦК-структурой с размером ОКР от 16 до 30 нм. Однокомпонентные покрытия обладают столбчатой структурой. Введение в состав W-покрытия Та (5...38 мас.%) приводит к подавлению столбчатого роста и формированию конденсата с более равноосными структурными элементами. Покрытия с такой структурой обладают наилучшими механическими свойствами (Н/Е-0,7...0,77)

Large-order Behaviour due to Ultraviolet Renormalons in QCD

Ultraviolet renormalons, contrary to their infrared counterparts, lead to a universal contribution to the large-order behaviour of perturbative expansions in QCD. In this letter, we determine nature of the leading ultraviolet renormalon singularity for the inclusive hadroproduction cross section in $e^+ e^-$ annihilation, for hadronic $\tau$ decays and the moments of deep-inelastic scattering structure functions. We comment on the relevance of ultraviolet renormalons to estimates in low orders of perturbation theory.Comment: 9 pages, LaTe

Phase separating binary fluids under oscillatory shear

We apply lattice Boltzmann methods to study the segregation of binary fluid mixtures under oscillatory shear flow in two dimensions. The algorithm allows to simulate systems whose dynamics is described by the Navier-Stokes and the convection-diffusion equations. The interplay between several time scales produces a rich and complex phenomenology. We investigate the effects of different oscillation frequencies and viscosities on the morphology of the phase separating domains. We find that at high frequencies the evolution is almost isotropic with growth exponents 2/3 and 1/3 in the inertial (low viscosity) and diffusive (high viscosity) regimes, respectively. When the period of the applied shear flow becomes of the same order of the relaxation time $T_R$ of the shear velocity profile, anisotropic effects are clearly observable. In correspondence with non-linear patterns for the velocity profiles, we find configurations where lamellar order close to the walls coexists with isotropic domains in the middle of the system. For particular values of frequency and viscosity it can also happen that the convective effects induced by the oscillations cause an interruption or a slowing of the segregation process, as found in some experiments. Finally, at very low frequencies, the morphology of domains is characterized by lamellar order everywhere in the system resembling what happens in the case with steady shear.Comment: 1 table and 12 figures in .gif forma