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81.
An exact solution of the Landau dispersion equation for Max well electron plasma oscillations has been obtained in the short-wavelength limit kr D » 1, where k is the wavenumber and r D is the Debye-Hückel screening radius. 相似文献
82.
N. V. Baydus S. M. Nekorkin D. A. Kolpakov A. V. Ershov V. Ya. Aleshkin A. A. Dubinov A. A. Afonenko 《Semiconductors》2016,50(11):1488-1492
A semiconductor laser with a new waveguide is developed. It allows significant narrowing of the directional pattern (to 4° in the plane perpendicular to the p–n junction). In the used waveguide, the minimum excess of the effective refractive index neff of the excitation mode over the substrate refractive index ns (neff–ns ? 1) is provided by selecting the thickness of Al0.3Ga0.7As confinement layers, which significantly increases the waveguide mode size and leads to directional-pattern narrowing. 相似文献
83.
Mareike Lalk Janin Reifenrath Nina Angrisani Alexandr Bondarenko Jan-Marten Seitz Peter P. Mueller Andrea Meyer-Lindenberg 《Journal of materials science. Materials in medicine》2013,24(2):417-436
Biocompatibility and degradation of magnesium sponges (alloy AX30) with a fluoride (MgF2 sponge, n = 24, porosity 63 ± 6 %, pore size 394 ± 26 μm) and with a fluoride and additional calcium-phosphate coating (CaP sponge, n = 24, porosity 6 ± 4 %, pore size 109 ± 37 μm) were evaluated over 6, 12 and 24 weeks in rabbit femurs. Empty drill holes (n = 12) served as controls. Clinical and radiological examinations, in vivo and ex vivo μ-computed tomographies and histological examinations were performed. Clinically both sponge types were tolerated well. Radiographs and XtremeCT evaluations showed bone changes comparable to controls and mild gas formation. The μCT80 depicted a higher and more inhomogeneous degradation of the CaP sponges. Histomorphometrically, the MgF2 sponges resulted in the highest bone and osteoid fractions and were integrated superiorly into the bone. Histologically, the CaP sponges showed more inflammation and lower vascularization. MgF2 sponges turned out to be better biocompatible and promising, biodegradable bone replacements. 相似文献
84.
Study of the formation processes of gold droplet arrays on Si substrates by high temperature anneals
Klimovskaya A Sarikov A Pedchenko Y Voroshchenko A Lytvyn O Stadnik A 《Nanoscale research letters》2011,6(1):151
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. 相似文献
85.
Fernando T. Andón Alexandr A. Kapralov Naveena Yanamala Weihong Feng Arjang Baygan Benedict J. Chambers Kjell Hultenby Fei Ye Muhammet S. Toprak Birgit D. Brandner Andrea Fornara Judith Klein‐Seetharaman Gregg P. Kotchey Alexander Star Anna A. Shvedova Bengt Fadeel Valerian E. Kagan 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(16):2721-2729
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. 相似文献
86.
V. Ya. Aleshkin A. A. Dubinov L. V. Gavrilenko Z. F. Krasilnik K. I. Kuritsyn D. I. Kryzhkov S. V. Morozov 《Semiconductors》2012,46(7):917-920
The results of experimental studies of the subpicosecond relaxation dynamics of photoexcited charge carriers in an In0.22Ga0.78As/GaAs quantum-well heterostructure are reported. From photoluminescence studies of the structure by the upconversion technique, the cooling rate of charge carriers in the quantum well and the time of charge-carrier trapping into the well are estimated to be ??1 ps at 300 K and at ??6.5 ps at 10 K. 相似文献
87.
Sergey V. Mirnov Andrey G. Alekseev Alexandr M. Belov Nadejda T. Djigailo Anastasiya N. Kostina Vladimir B. Lazarev Igor E. Lyublinski Vladislav M. Nesterenko Aleksei V. Vertkov Vladimir A. Vershkov 《Fusion Engineering and Design》2012,87(10):1747-1754
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. 相似文献
88.
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. 相似文献
89.
Valentina A. Markusova Margriet Jansz Alexandr N. Libkind Ilya Libkind Alexander Varshavsky 《Scientometrics》2009,79(2):249-260
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
Our paper is a part of a project designed to trace R&D development in a transition economy and knowledge transfer from basic
research to innovation. Results of our project shed light on science policy and the social issues due to the indiscriminate
introduction of quantitative indicators. 相似文献
(1) | publication output and citedness have to be considered in relation to the level of expenditure on R&D |
(2) | bibliometric indicators depend strongly on the database used (ISI’s databases are biased) and their interpretation can be confusing; better coverage of Russian publications or a Russian Science Citation Index are needed. Also, research results are communicated in more ways than paper publications. |
(3) | policy makers have misused ISI statistics to demonstrate “a low level” of Russian R&D. |
90.
Pavel A. Domnin Vladislav A. Parfenov Alexey S. Kononikhin Stanislav V. Petrov Nataliya V. Shevlyagina Anastasia Yu. Arkhipova Elizaveta V. Koudan Elizaveta K. Nezhurina Alexander G. Brzhozovskiy Anna E. Bugrova Anastasia M. Moysenovich Alexandr A. Levin Pavel A. Karalkin Frederico D. A. S. Pereira Vladimir G. Zhukhovitsky Elena S. Lobakova Vladimir A. Mironov Evgeny N. Nikolaev Yusef D. Khesuani Svetlana A. Ermolaeva 《International journal of molecular sciences》2022,23(3)
Changes in bacterial physiology caused by the combined action of the magnetic force and microgravity were studied in Escherichia coli grown using a specially developed device aboard the International Space Station. The morphology and metabolism of E. coli grown under spaceflight (SF) or combined spaceflight and magnetic force (SF + MF) conditions were compared with ground cultivated bacteria grown under standard (control) or magnetic force (MF) conditions. SF, SF + MF, and MF conditions provided the up-regulation of Ag43 auto-transporter and cell auto-aggregation. The magnetic force caused visible clustering of non-sedimenting bacteria that formed matrix-containing aggregates under SF + MF and MF conditions. Cell auto-aggregation was accompanied by up-regulation of glyoxylate shunt enzymes and Vitamin B12 transporter BtuB. Under SF and SF + MF but not MF conditions nutrition and oxygen limitations were manifested by the down-regulation of glycolysis and TCA enzymes and the up-regulation of methylglyoxal bypass. Bacteria grown under combined SF + MF conditions demonstrated superior up-regulation of enzymes of the methylglyoxal bypass and down-regulation of glycolysis and TCA enzymes compared to SF conditions, suggesting that the magnetic force strengthened the effects of microgravity on the bacterial metabolism. This strengthening appeared to be due to magnetic force-dependent bacterial clustering within a small volume that reinforced the effects of the microgravity-driven absence of convectional flows. 相似文献