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61.
Victor V. Lozanov Aleksei V. Utkin Tatyana A. Gavrilova Anatoly T. Titov Anatoly I. Beskrovny Gleb A. Letyagin Galina V. Romanenko Natalya I. Baklanova 《Journal of the American Ceramic Society》2022,105(3):2323-2333
A variety of the ternary Hf–Ir–B phases formed via the reaction between iridium and hafnium diboride at elevated temperatures was found. The data on the phase and elemental composition, as well as crystal structure, obtained by powder and single-crystal X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectrometer, and time-of-flight neutron diffraction analysis unambiguously confirm that HfIr3Bx solid solution, two known ternary borides (HfIr3B4, Hf2Ir5B2), as well as two novel ternary HfIr2.1B1.3 and HfIr5.7B2.7 phases, are formed at elevated temperatures. This result is fundamentally different from that previously obtained by us for the Hf–Ir–C system in which only one binary intermetallic compound, HfIr3, was produced. The measured Vickers microhardness for all the aforementioned ternary borides (13–19 GPa) allows us to consider them hard. The coefficients of thermal expansion of ternary borides were measured by in situ high-temperature X-ray analysis. 相似文献
62.
63.
Marina M. Silantyeva Natalya V. Ovcharova Ekaterina B. Andreeva Alexandr A. Kuznetsov 《The International journal of environmental studies》2015,72(3):501-508
The paper presents floristic and geo-botanical characteristics of rare forest ecosystems of the south of Western Siberia – spruce forests on the site of the Ob river ancient bed within the modern Bolshaya Sogra within the boundaries of the state natural reserve ‘Kislukhinsky’ (Altai region). Spruce forests here are at the edge of their spread in the West Siberian Plain conditions. There are over 300 species of vascular plants found in these spruce forests. Among them are plants that are typical of the mountain taiga associations of Russian Altai, as well as orchids, which have high species diversity. Spruce forest set of associations is also varied. The uniqueness of the described communities to the south of Western Siberia, the large number of rare and endangered plant species listed in the Red Books of different ranks, as well as the boreal forest species complex rare to the lowland wooded steppe, which has a relict character, all served as the basis for allocating a special protection area in the ‘Kislukhinsky’ reserve and attributing the studied spruce forests to the forests of high conservation value. 相似文献
64.
Manuel E. Palomar Crescencio O. Olivares-Xometl Natalya V. Likhanova Jonathán-Boanerge Pérez-Navarrete 《Journal of surfactants and detergents》2011,14(2):211-220
Seven cationic surfactants: 1-methyl-3-tetradecyl imidazolium bromide, 1-methyl-3-hexadecyl imidazolium bromide, N,N-tetradecyl pyridinium bromide, N,N-hexadecyl pyridinium bromide, N,N-dimethyl-N-ethylbenzyl ammonium bromide, N,N-dimethyl-N-ethylbenzyl ammonium laurate and N,N-dimethyl-N-ethylbenzyl ammonium acetate, were investigated at different doses (10, 25, 50, 100, and 200 ppm) as corrosion inhibitors
for steel grade API 5L X52 in hydrochloric acid 2 M using a weight loss technique, impedance and polarization resistance methods.
The corrosion inhibition of steel grade API 5L X52 of the cationic surfactants was attributed to their molecular structure
(heterocyclic ring, hydrophobic chain length and counterion) that enhances adsorption onto steel surface. The best protective
efficiency of the film was higher than 90% (N,N-Dimethyl-N-ethylbenzyl ammonium acetate). It is important to know how organic inhibitor films grown on the metallic surface in order
to achieve superior corrosion inhibition, hence experimental findings were described by Langmuir adsorption isotherm. The
Electrochemical Impedance Spectroscopy spectrums were fitted by means of the Voigt model. 相似文献
65.
Natalya N. AndrianovaAnatoly M. Borisov Eugenia S. Mashkova Yury S. Virgiliev 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(9):861-864
The ion-induced erosion, determining by sputtering yield Y and surface evolution including structure and morphology changes of the modified surface layers, of two commercial carbon fiber composites (CFC) with different reinforcement - KUP-VM (1D) and Desna 4 (4D) have been studied under 30 keV Ar+ high fluence (φt ∼ 1018-1020 ion/cm2) irradiation in the temperature range from room temperature to 400 °C. Ion-induced erosion results in the changes of carbon fiber structure which depend on temperature and ion fluence. Monitoring of ion-induced structural changes using the temperature dependence of ion-induced electron emission yield has shown that for Desna 4 and KUP-VM at dynamic annealing temperature Та ≈ 170 °С the transition takes place from disordering at T < Ta to recrystallization at T > Ta. The annealing temperature Та is close to the one for polycrystalline graphites. Microscopy analysis has shown that at temperatures Т < Ta the etching of the fibers results in a formation of trough-like longitudinal cavities and hillocks. Irradiation at temperatures T > Ta leads to a crimped structure with the ribs perpendicular to fiber axis. After further sputtering of the crimps the fiber morphology is transformed to an isotropic globular structure. As a result the sputtering yield decreases for Desna 4 more than twice. This value is almost equal to that for KUP-VM, Desna 4, polycrystalline graphites and glassy carbons at room temperature. 相似文献
66.
This paper presents the main results of a comprehensive assessment of GHG mitigation options in Ukraine. The primary focus is the energy sector. According to the prognosis of the baseline scenario, which assumes that the GDP reaches the level of 1990 in the 2005–2010 period, net GHG emissions would exceed the 1990 level by around 2005. The baseline scenario includes implementation of national programs to promote the adoption of technologies and practices that improve the efficiency of energy use. A mitigation scenario was created that includes widespread adoption of such technologies and practices in all sectors. Energy-saving technologies play the most important role in reducing emissions in this scenario. Relative to the baseline scenario, net GHG emissions in 2015 are 46% lower. The estimated incremental capital investment required for the mitigation scenario is $30–35 billion. 相似文献
67.
A mixture of high‐density polyethylene and its low‐molecular‐weight analogue heptadecane was studied. The mixture behaved as a compound, that is, differently from polyethylene. Heptadecane reduced the crystallinity of polyethylene, and it intricately changed the concentration of centers sorbing phenyl‐β‐naphthylamine, the antioxidant, and simultaneously changed the equilibrium constant of sorption. Heptadecane also prolonged the duration of the antioxidant action in polyethylene. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2597–2603, 2003 相似文献
68.
Svetlana Rogovina Eduard Prut Kristine Aleksanyan Vadim Krasheninnikov Evgeniya Perepelitsyna Dmitrii Shashkin Natalya Ivanushkina Aleksandr Berlin 《应用聚合物科学杂志》2019,136(22):47598
Under conditions of shear deformations, low-density polyethylene (LDPE) and polylactide (PLA) composites are obtained in rotor disperser. The production of these composites allows one to use polymers derived from natural raw and to reduce the cost of the materials on their base. The addition of rigid PLA leads to increase in elastic modulus from 200 for LDPE to 1190 for LDPE–PLA (50:50 wt %) composites and in tensile strength from 13.3 for LDPE to 17.8 for LDPE–PLA. By differential scanning calorimetry method, it is shown that LDPE and PLA are incompatible. Using X-ray diffraction analysis, it is found that degree of crystallinity of composites decreases from 46.1 at 50:50 wt % to 36.9 at 80:20 wt % component ratios with the rise in LDPE content. Tests on fungus resistance show that the composites containing 50 wt % PLA are more resistant than the composites containing 30 wt % PLA. First by gel-permeation chromatography method, it is shown that composite degradation after exposure in soil is accompanied by the PLA chain scission and depolymerization with formation of monomers and dimers (M w of PLA decreases from 118,860 to 80,100). The obtained composites can be applied as packaging materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47598. 相似文献
69.
Ludmila Lukyanova Elita Germanova Natalya Khmil Lybov Pavlik Irina Mikheeva Maria Shigaeva Galina Mironova 《International journal of molecular sciences》2021,22(16)
This study was the first comprehensive investigation of the dependence of mitochondrial enzyme response (catalytic subunits of mitochondrial complexes (MC) I-V, including NDUFV2, SDHA, Cyt b, COX1 and ATP5A) and mitochondrial ultrastructure in the rat cerebral cortex (CC) on the severity and duration of in vivo hypoxic exposures. The role of individual animal’s resistance to hypoxia was also studied. The respiratory chain (RC) was shown to respond to changes in environmental [O2] as follows: (a) differential reaction of mitochondrial enzymes, which depends on the severity of the hypoxic exposure and which indicates changes in the content and catalytic properties of mitochondrial enzymes, both during acute and multiple exposures; and (b) ultrastructural changes in mitochondria, which reflect various degrees of mitochondrial energization. Within a specific range of reduced O2 concentrations, activation of the MC II is a compensatory response supporting the RC electron transport function. In this process, MC I develops new kinetic properties, and its function recovers in hypoxia by reprograming the RC substrate site. Therefore, the mitochondrial RC performs as an in vivo molecular oxygen sensor. Substantial differences between responses of rats with high and low resistance to hypoxia were determined. 相似文献
70.
Ivan B. Filippenkov Vasily V. Stavchansky Natalya Yu. Glazova Elena A. Sebentsova Julia A. Remizova Liya V. Valieva Natalia G. Levitskaya Nikolai F. Myasoedov Svetlana A. Limborska Lyudmila V. Dergunova 《International journal of molecular sciences》2021,22(18)
Natural melanocortins (MCs) have been used in the successful development of drugs with neuroprotective properties. Here, we studied the behavioral effects and molecular genetic mechanisms of two synthetic MC derivatives-ACTH(4–7)PGP (Semax) and ACTH(6–9)PGP under normal and acute restraint stress (ARS) conditions. Administration of Semax or ACTH(6–9)PGP (100 μg/kg) to rats 30 min before ARS attenuated ARS-induced behavioral alterations. Using high-throughput RNA sequencing (RNA-Seq), we identified 1359 differentially expressed genes (DEGs) in the hippocampus of vehicle-treated rats subjected to ARS, using a cutoff of >1.5 fold change and adjusted p-value (Padj) < 0.05, in samples collected 4.5 h after the ARS. Semax administration produced > 1500 DEGs, whereas ACTH(6–9)PGP administration led to <400 DEGs at 4.5 h after ARS. Nevertheless, ~250 overlapping DEGs were identified, and expression of these DEGs was changed unidirectionally by both peptides under ARS conditions. Modulation of the expression of genes associated with biogenesis, translation of RNA, DNA replication, and immune and nervous system function was produced by both peptides. Furthermore, both peptides upregulated the expression levels of many genes that displayed decreased expression after ARS, and vice versa, the MC peptides downregulated the expression levels of genes that were upregulated by ARS. Consequently, the antistress action of MC peptides may be associated with a correction of gene expression patterns that are disrupted during ARS. 相似文献