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71.
Natalia S Serkhacheva Nikolay I Prokopov Elena V Chernikova Elena Y Kozhunova Inna O Lebedeva Oleg V Borisov 《Polymer International》2019,68(7):1303-1314
Emulsifier‐free batch emulsion polymerization of n‐butyl acrylate and its semi‐batch copolymerization with 2,2,3,3,4,4,5,5‐octafluoropentyl acrylate and 2,2,3,4,4,4‐hexafluorobutyl acrylate both mediated by poly(acrylic acid) containing the trithiocarbonate group in the chain was employed to produce amphiphilic triblock copolymers. The polymerization‐induced self‐assembly of these copolymers in aqueous media gave rise to spherical core–shell particles. Irrespective of the experimental conditions, the polymeric product was characterized by a bimodal molecular weight distribution. The apparent violation of the reversible addition–fragmentation chain transfer polymerization mechanism may be attributed to restricted accessibility of the trithiocarbonate group in the self‐assembled block copolymers for propagating radicals that enter into the particle. Mean‐field theoretical arguments were employed to explain the exclusively spherical morphology of the particles observed in the experiment. © 2019 Society of Chemical Industry 相似文献
72.
Tcherkasskaya Olga; Ptitsyn Oleg B. 《Protein engineering, design & selection : PEDS》1999,12(6):485-490
The direct energy transfer technique was modified and appliedto probe the relative localization of apomyoglobin A-, G- andH-helixes, which are partly protected from deuterium exchangein the equilibrium molten globule state and in the molten globule-likekinetic intermediate. The non-radiative transfer of tryptophanelectronic energy to 3-nitrotyrosine was studied in differentconformational states of apomyoglobin (native, molten globule,unfolded) and interpreted in terms of average distances betweengroups of the protein chain. The experimental data show thatthe distance between the middle of A-helix and the N-terminusof G-helix as well as the distance between the middle of theA-helix and the C-terminus of the H-helix in the molten globulestate are close to those in the native state. This is a strongargument in favor of similarity of the overall architectureof the molten globule and native states. 相似文献
73.
Oleg N. Grigoriev Boris A. Galanov Vladimir A. Lavrenko Alla D. Panasyuk Sergey M. Ivanov Alexandr V. Koroteev Klaus G. Nickel 《Journal of the European Ceramic Society》2010,30(11):2397-2405
The oxidation of ZrB2–SiC and ZrB2–SiC–ZrSi2 ceramics of different composition has been studied experimentally at 1500 °C in pure oxygen for up to 50 h. ZrB2–SiC–ZrSi2 ceramics proved to be the most oxidation-resistant at ZrSi2 contents of less then 4 wt%. These ceramics were more oxidation-resistant than ZrB2–SiC ceramics. An analytical model of growth kinetics for a multilayered scale based on an oxidation–diffusion balance was developed and tested. 相似文献
74.
Novel hydrogen gas sensor based on single ZnO nanorod 总被引:1,自引:0,他引:1
For extensive use in an industrialized process of individual ZnO nano/microrods as building nanoblock in novel hydrogen sensors, a simple, inexpensive, and bio-safe synthesis process and nanofabrication route is required. Here, we report a cost-effective and fast synthesis route for ZnO one-dimensional nanorod using an aqueous-based approach in a reactor. Our synthesis technique permits nano/microrods to be easily transferred to other substrates and to be distributed on the surface. This flexibility of substrate choice opens the possibility of using focused ion beam (FIB/SEM) system for handling and fabricating nanosensors. The main advantage of this procedure is a quick verification/testing of concept and is compatible with micro/nanoelectronic devices. The described nanofabrication steps permitted us to obtain a 90% success rate for building single nanorod sensor. A sensitivity of ∼4% was obtained for a single ZnO nanorod hydrogen sensor at 200 ppm H2 in the air at room temperature. The nanosensor has a high selectivity for H2, since its sensitivity for O2, CH4, CO, ethanol or LPG are less than 0.25%. 相似文献
75.
A problem of the film type condensation of the pure vapor on disk-shaped fin is considered with taking into account the essential influence of the capillary forces. Calculations for FC-72 condensation on such fin have been performed at microgravity conditions. A hump on the condensate film thickness curve is occurred on the concave part of the fin due to the additional curvature of the disc shape. The results have been compared to results for straight fin with the same surface area of condensation. Condensate outflow from the disk-shaped film is greater than from straight fin. 相似文献
76.
Oleg Vasylkiv Yoshio Sakka Yasuaki Maeda Valeriy V. Skorokhod 《Journal of the American Ceramic Society》2005,88(3):639-644
A uniformly aggregated 3 mol% yttria-stabilized tetragonal zirconia nano-powder (3Y-TZP) was prepared using thermal hydrolysis and the ultrasonic deagglomeration technique. The possibility of nano-engineering of Pt–3Y-TZP composite aggregates was studied. The as-synthesized Pt nano-particles (∼2 nm) were impregnated into zirconia nano-aggregates (20–45 nm). The morphology manipulation technique allowed production of the composite zirconia-based aggregates in which a significant fraction of the Pt particles was embedded into the densified zirconia aggregates. Using the colloidal technique and low-temperature (1150°C) sintering, we prepared the Pt-zirconia (0.5–1.5 wt% of platinum) nano-composites with average 3Y-TZP grain sizes of 120 nm, and with the platinum grains size in the range of 20–60 nm. The catalytic properties of composite Pt–3Y-TZP nano-composites were studied and described. 相似文献
77.
Sergey N. Gorodsky Lev G. Bruk Alexandra E. Istomina Anatoly V. Kurdiukov Oleg N. Temkin 《Topics in Catalysis》2009,52(6-7):557-562
This article dedicated to study of few oscillating reactions in homogeneous systems. The experimental data and preliminary mechanism are reported. The authors affirm they find new type of oscillating processes—the reactions of carbonylation. 相似文献
78.
Biclustering consists in simultaneous partitioning of the set of samples and the set of their attributes (features) into subsets (classes). Samples and features classified together are supposed to have a high relevance to each other. In this paper we review the most widely used and successful biclustering techniques and their related applications. This survey is written from a theoretical viewpoint emphasizing mathematical concepts that can be met in existing biclustering techniques. 相似文献
79.
Oleg I. Belous Anatoliy I. Fisun Ivan P. Olchovskiy Svetlana P. Sirenko 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(9):1451-1462
The construction and operating characteristics of the highly stabilized millimeter wave IMPATT oscillator are described. The frequency stability is 8.1 × 10-7 at 115 GHz. The output power is no less than 15 mW. The sphere-corner-echelette open resonator have been used for oscillator stabilization. This approach is also adaptable to the Gunn oscillator. 相似文献
80.
Nikolay O. Mchedlov‐Petrossyan Kateryna V. Roshchyna Sergey V. Shekhovtsov Sergey V. Eltsov Oleksii S. Zozulia Irina V. Omelchenko Oleg V. Shishkin 《Coloration Technology》2015,131(3):236-244
Among the vast series of phenolsulfonephthalein dyes, the nitro derivatives and especially 3,3′,5,5′‐tetranitrophenolsulfonephthalein (nitrophenol crimson) remain practically unexplored, whereas the halogen and alkyl derivatives have been studied comprehensively. This striking difference is probably due to the enormous influence of the four NO2 groups on the properties of the dye. As a result, the protolytic behaviour is unlike even that of tetrabromo phenolsulfonephthalein, and the recognised scheme of acid–base and tautomeric equilibrium of the sulfonephthaleins is unable to explain it. The molecular form H2R was isolated as a sultonic tautomer, and an X‐ray crystal structure analysis was carried out. Our studies of the UV‐vis absorption spectra in water, methanol, dimethyl sulfoxide, acetonitrile, acetone, and dichloromethane, as well as in aqueous micellar solutions of surfactants, allowed us to evaluate the true molar absorptivity of the dianion R2?, and to elucidate the enormous tendency to form yellow trianionic carbinol ROH3?, even in the presence of traces of H2O. Nuclear magnetic resonance and electrospray data confirm the proposed scheme of ionisation and tautomerism of nitrophenol crimson. 相似文献