Study of the formation processes of gold droplet arrays on Si substrates by high temperature anneals

In this study, the peculiarities of the transformations of gold films deposited on the Si wafer surfaces as a result of high temperature anneals are investigated experimentally depending on the conditions of wafer surface preparation and the annealing regimes. The morphology and the distribution functions of the crystallites of gold films as well as the gold droplets formed as a result of anneals are studied as functions of annealing temperature, type of annealing (rapid thermal or rapid furnace annealing), and the state of the surface of Si wafers. The results obtained can be used for the controlled preparation of the arrays of catalytic gold droplets for subsequent growth of Si wire-like crystals.     

Biodegradation of Single‐Walled Carbon Nanotubes by Eosinophil Peroxidase

Eosinophil peroxidase (EPO) is one of the major oxidant‐producing enzymes during inflammatory states in the human lung. The degradation of single‐walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H₂O₂ is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H₂O₂ alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV‐visible‐NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials.     

Li collection experiments on T-11M and T-10 in framework of Li closed loop concept

The concept of a steady state tokamak with plasma facing components (PFC) on the basis of liquid lithium circulation demands the decision of three tasks: lithium injection to the plasma, lithium ions collection before their deposition on the vacuum vessel and lithium returning to the injection zone. Main subject of paper is the investigations of Li collection by different types of limiters intersected the scrape-of-layer (SOL) in T-10 and T-11M tokamaks. For finding solution for this problem in T-11M and T-10, experiments have been applied with Li-, C-rail limiters and ring SS R-limiter-collector (T-11M). The efficiency of Li collection by limiters in T-11M and T-10 tokamaks was investigated by post mortem sample–witness analysis and (T-11M) by the use of the mobile graphite probe (limiter) as a recombination target in the stream of lithium ions. The characteristic depth of lithium penetration in the SOL area of T-11M is about 2 cm and 4 cm in SOL of T-10. The quantitative analysis of the sample–witnesses located on T-11M limiters showed that 60 ± 20% of the lithium injected during plasma operating of T-11M had been collected by limiters. It confirms an opportunity of the lithium ions collection by limiters in tokamak SOL.     

Determination of photophysical parameters of red fluorescent protein mRFP1 under ultraviolet excitation by methods of laser fluorimetry

We investigate photophysical processes that take place in macromolecules of a fluorescent protein mRFP1 under UV excitation [when the energy transfer in a localized donor-acceptor (LDA) pair, which is presented in the molecules of the protein, becomes apparent]. We used a special approach based on the fluorescence laser spectroscopy technique. The energy transfer rates in LDA pairs and photophysical parameters of fluorophores (chromophores) of three spectral forms, which coexist in the ensemble of the macromolecules of this protein, were determined under pulse UV laser excitation.     

Pulse current treatment effect on the strength of reinforcing steel and its weld joint under impact loading

We present results of static and impact tension tests of as-received reinforcing steel specimens, specimens with weld joints in their test portion, as well as specimens pretreated by high-density pulse current. As test results demonstrate, an increased strain rate enhances strength, and the pulse current treatment greatly influences the strength and plasticity of a defect-containing weld metal under static and impact tension. Translated from Problemy Prochnosti, No. 3, pp. 89–96, May–June, 2009.     

Trends in Russian research output in post-Soviet era

Recently, the Russian government has ordered evaluation and reform of the basic research system. As a consequence, the number of research staff at the Russian Academy of Sciences will be reduced by 20% by 2007. The basis for research evaluation and institute budgeting will be bibliometric indicators. In view of these changes we look at the Russian publication output and argue that

The effect of retained austenite on contact fatigue in Cr−Ni−W carburized steel

This article describes an experiment to determine the effect of retained austenite on the chipping of the case-hardened layer of Cr−Ni−W carburized steel by examining the same case-hardened layer with varying amounts of retained austenite after different heat treatments. The existence of a critical load level was established; contact fatigue resistance can be improved when the loads are above critical. This is determined by deformation of the austenite structure and substructure, the austenite-martensite transformation under the influence of the load, and the retention of the deformed austenite structure in the martensite. Authors' Note: Alloyed steel compositions are presented in the Soviet standard. The first two numbers give the approximate carbon content in hundredths of a percent. The number after the element shows the approximate percentage of the alloying elements. The number one or no number at all means the percentage is about one or less. Bertold B. Vinokur earned his Doctor of Technical Science in physics of metals and metal science at the Ukrainian Academy of Science, Ukraine, in 1978. He is currently retired. Dr. Vinokur is a member of TMS. Alexandr L. Geller earned his Doctor of Technical Science in metal science and heat treatment at Donetsk Technical University, Ukraine, in 1997. He is currently an assistant professor in the Department of Materials Science and Engineering at Donetsk Technical University, Donetsk, Ukraine.     

Observation of latent ion tracks in semicrystalline polymers by scanning electron microscopy

Advances in nanotechnology and materials science require further improvement of metrology of nanostructured polymers, in particular, polymers modified by high energy ion beams. The observation of latent ion tracks using various microscopy methods is an important part of studies on heavy ion effects in solids. However, scanning electron microscopy (SEM) has not been utilized for polymers. In the present study, it is shown how SEM can be used to observe latent tracks in semicrystalline polymers. The procedure includes the embrittlement of a polymer specimen by controlled photooxidation and its subsequent fracture. Latent tracks are clearly visible on fractured surfaces as structureless stripes surrounded by an inhomogeneous semicrystalline matrix. Using this method, the latent tracks of Kr, Xe, Au, and Bi ions with energies of 1–11 MeV/u in polyethylene terephthalate and polypropylene films are observed and their diameters are estimated. In contrast to transmission electron microscopy, the suggested novel technique detects the outer track shell consisting of an amorphized polymer. Therefore, SEM observations can complement other commonly used techniques to comprehensively characterize the structure of ion tracks in polymers.