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71.
E. A. Filonova A. N. Demina E. A. Kleibaum L. Ya. Gavrilova A. N. Petrov 《Inorganic Materials》2006,42(4):443-447
We have revealed the formation of a continuous series of orthorhombic LaMn1 ? y FeyO3 solid solutions (0<y<1); La1 ? x SrxFeO3 solid solutions in the composition range 0 < x ≤ 0.8, with an orthorhombic structure at 0 < x ≤ 0.6 and a cubic structure at 0.6 < x ≤ 0.8; and a tetragonal SrMn1 ? y FeyO3 phase in the range 0.6 ≤ y ≤ 1. The composition stability limits of the perovskite phase La1 ? x SrxMn1 ? y FeyO3 have been determined, and the 1100°C isotherm of the La2O3-SrO-Mn3O4-Fe2O3 system in air has been constructed. 相似文献
72.
Corrosion-resistant analogue of Hadfield steel 总被引:2,自引:0,他引:2
V.G. Gavriljuk A.I. Tyshchenko O.N. Razumov Yu.N. Petrov B.D. Shanina H. Berns 《Materials Science and Engineering: A》2006,420(1-2):47-54
The concept of alloying austenitic steels with carbon + nitrogen is used for the development of a corrosion-resistant austenitic CrMn steel having an impact wear resistance close to that of the Hadfield steel. A higher stabilization of the austenitic phase by C + N, as compared to carbon or nitrogen alone, is substantiated by ab initio calculation of the electron structure, measurements of the concentration of free electrons and calculations of the phase equilibrium. Based on these results, the compositions (mass%) Cr18Mn18C0.34N0.61 and Cr18Mn18C0.49N0.58 were melted and tested along with Hadfield steel Mn12C1.2. Mechanical tests have shown that, as compared to the Hadfield steel, the experimental steels possess a higher strength, plasticity, hardness and the same resistance to impact wear. TEM studies of the surface layer after impact treatment revealed a mixture of the amorphous phase, nanocrystals and fine-twinned austenite. At the same time, using Mössbauer spectroscopy of conversion electrons, the ferromagnetic ordering was found in the surface layer of up to 10 μm in depth, which is the sign of the strain-induced martensitic phase. The hypothesis of a transition from the low-spin to the high-spin state of the iron atoms within the thin twins in austenite was proposed in order to interpret the discrepancy between TEM and Mössbauer studies. Potentiodynamic measurements and immersion tests show that the CrMnCN steels possess a significantly higher pitting potential and resistance to general corrosion in comparison with Hadfield steel. 相似文献
73.
M. H. Thoma H. Höfner M. Kretschmer S. Ratynskaia G. E. Morfill A. Usachev A. Zobnin O. Petrov V. Fortov 《Microgravity science and technology》2006,18(3-4):47-50
PK-4 is an experiment designed to investigate complex plasmas (low-temperature plasmas containing microparticles, e.g. dust grains) in a combined dc/rf discharge under microgravity conditions on board of the International Space Station. Within the 35th and 36th ESA parabolic flight campaigns first experiments under microgravity conditions in a specially designed experiment set-up have been performed. The particle flow inside the tube, the appearance of dust waves, and lane formation in interpenetrating particle clouds have been observed. 相似文献
74.
A. Nikolic Lj. Petrov Dj. Koruga S. Mihajlovic 《Fullerenes, Nanotubes and Carbon Nanostructures》2005,13(1):53-59
Magnetic behavior of C60 thin films in the Earth's magnetic field under polarization light influence is presented. Transformation of magnetic field for two fullerene thin films of different thickness is investigated. Two proton magnetometers were used for these measurements. Samples of 30 nm and 250 nm thickness illustrate a significant change of magnetic field intensity under the influence of polarization light, in range from 3.4 to 12.9 nT, for 200 measurement data per sample. 相似文献
75.
V. V. Petrov A. A. Kryuchin S. M. Shanoylo V. I. Sidorenko 《Cybernetics and Systems Analysis》2003,39(5):777-782
Potentialities of the methods of information processing, distribution, and storage are analyzed. Directions are defined in which optical information media characteristics can be improved. Possibility of using optical media for a long-term storage of digital information is considered. 相似文献
76.
Petrov S. I. Kaidash A. P. Krasovitskii D. M. Sokolov I. A. Pogorel’skii Yu. V. Chalyi V. P. Shkurko A. P. Stepanov M. V. Pavlenko M. V. Baranov D. A. 《Technical Physics Letters》2004,30(7):580-582
Technical Physics Letters - InGaN/GaN heterostructures have been grown by molecular beam epitaxy (MBE) using ammonia as a source of nitrogen. The influence of the growth temperature and rate on the... 相似文献
77.
P. Petrov 《Zeitschrift für Jagdwissenschaft》1972,18(2):66-76
Zusammenfassung Durch Rundfrage und ergänzende Untersuchungen wurde der gegenwärtige Bestand an Auerwild im südlichen Teil des Verbreitungsgebiets der Art ermittelt. Gegenwärtig leben in Bulgarien etwa 2600 Stück in fünf Vorkommen mit Schwerpunkten in den Rhodopen (70%) und im Rilagebirge (20%). Der zahlenmäßige Rückgang und das Verschwinden an den Rändern der Vorkommensgebiete wird für die letzten 50 Jahre dargestellt. Die Ursache für den Rückgang ist in der zunehmenden Nutzung der Wälder und in der Störung durch die wirtschaftliche Tätigkeit und den Verkehr zu suchen.
Summary By means of questionnaires and supplementary studies, the present conditions of Capercaillie in the southern part of its habitat was ascertained. Currently, about 2,600 birds are living in Bulgaria in five main areas, with concentrations in the Rhodope (70%) and in the Rila Moun-
Résumé Par voie d'enquête complétée par des recherches, l'effectif actuel de l'Urogalle est établi pour la partie méridionale de l'aire d'extension de l'espèce: quelque 2600 têtes d'Urogalle sont réparties en cinq stations, principalement dans les Rhodopes (70%) et dans le Mont Rila (20%). On fait état de la régression de l'espèce en périphérie de son aire de dispersion au cours des cinquante dernières années.Les causes de cette diminution sont à rechercher dans l'exploitation de plus en plus intensive des forêts, dans l'activité économique croissante et dans le développement des voies de communication.相似文献
78.
Alexander Blagov Elena B. Zhigmitova Margarita A. Sazonova Liudmila M. Mikhaleva Vladislav Kalmykov Nikolay K. Shakhpazyan Varvara A. Orekhova Alexander N. Orekhov 《International journal of molecular sciences》2022,23(9)
Crohn’s disease remains one of the challenging problems of modern medicine, and the development of new and effective and safer treatments against it is a dynamic field of research. To make such developments possible, it is important to understand the pathologic processes underlying the onset and progression of Crohn’s disease at the molecular and cellular levels. During the recent years, the involvement of mitochondrial dysfunction and associated chronic inflammation in these processes became evident. In this review, we discuss the published works on pathogenetic models of Crohn’s disease. These models make studying the role of mitochondrial dysfunction in the disease pathogenesis possible and advances the development of novel therapies. 相似文献
79.
80.
Double‐layered hydrogels of super‐macroporous poly(2‐hydroxyethyl methacrylate) (PHEMA) cryogel core and poly(ethylene oxide) (PEO) hydrogel outer layer for encapsulation of the enzyme urease were constructed. The enzyme was entrapped into the pores of PHEMA cryogel by soaking and then the core was covered with a PEO layer. The leaking of urease from the core was prevented when the density of the PEO network was increased by incorporation of the crosslinking agent, poly(ethylene glycol) diacrylate. The hybrid system exhibited a nearly constant enzyme activity with time and maintained its structural integrity after several reactions of hydrolysis of urea. The potential of double‐layered hydrogels containing urease for establishment of water pollution with copper was investigated as well. Copyright © 2011 Society of Chemical Industry 相似文献