Деградация человеческого потенциала как фактор латентной составляющей деятельности высшей школы Украины

Рассмотрены проблемы тенизации и коррупционности функционирования украин-ской высшей школы на фоне вектора развития показателей потенциала населения страны.Розглянуті проблеми тінізації і коррупційності функціонування української вищої школи на тлі вектору розвитку показників потенціалу населення країни

In Situ Transmission Electron Microscopy to Study the Location and Distribution Effect of Pt on the Reduction of Co3O4–SiO2

The addition of Pt generally promotes the reduction of Co3O4 in supported catalysts, which further improves their activity and selectivity. However, due to the limited spatial resolution, how Pt and its location and distribution affect the reduction of Co3O4 remains unclear. Using ex situ and in situ ambient pressure scanning transmission electron microscopy, combined with temperature-programmed reduction, the reduction of silica-supported Co3O4 without Pt and with different location and distribution of Pt is studied. Shrinkage of Co3O4 nanoparticles is directly observed during their reduction, and Pt greatly lowers the reduction temperature. For the first time, the initial reduction of Co3O4 with and without Pt is studied at the nanoscale. The initial reduction of Co3O4 changes from surface to interface between Co3O4 and SiO2. Small Pt nanoparticles located at the interface between Co3O4 and SiO2 promote the reduction of Co3O4 by the detachment of Co3O4/CoO from SiO2. After reduction, the Pt and part of the Co form an alloy with Pt well dispersed. This study for the first time unravels the effects of Pt location and distribution on the reduction of Co3O4 nanoparticles, and helps to design cobalt-based catalysts with efficient use of Pt as a reduction promoter

Isomeric periodic mesoporous organosilicas with controllable properties

The synthesis procedure for isomeric periodic mesoporous organosilicas with E-configured ethenylene bridges was investigated using the homemade pure E-isomer of 1,2-bis(triethoxysilyl)ethene. The pH, aging temperature and the presence of cosolvents played a key role in obtaining well-ordered mesoporous materials with controllable properties and morphologies. By fine-tuning the reaction mixture acidity, PMOs with high surface areas and pore volumes could be attained. By selecting various alcohols as cosolvents and optimizing the alcohol concentration, PMOs with crystal-like disc shaped, fibrous and spherical particle morphologies were obtained. The synthesis temperature of these ethenylene-bridged PMOs influences the pore size, structure, connectivity and volume

Tailoring and visualizing the pore architecture of hierarchical zeolites

Recently the concept of hierarchical zeolites invoked more explicit attention to enhanced accessibility of zeolites. By realizing additional meso-/macroporosity with the intrinsic microporosity of zeolites, a hierarchical pore system arises which facilitates mass transport while maintaining the zeolite shape selectivity. A great number of synthesis strategies have been developed for tailoring the pore architecture of hierarchical zeolites. In this review, we give a general overview of different synthesis methods for introduction of additional porosity. Advantages and limitations of these different synthesis approaches are addressed. The assessment of pore structure is essential to build the link between the zeolite pore structure and its functionality. A variety of 2D and 3D microscopy techniques are crucial to visualize the hierarchical pore structure, providing unique and comprehensive information that, however, should be linked to the results of bulk characterization techniques as much as possible. The microscopy techniques are classified and discussed according to the different probes used, such as optical light, X-rays and electrons. Representative work is reviewed to elucidate the capability of each technique and their drawbacks

Carbon Nanofiber Growth Rates on NiCu Catalysts: Quantitative Coupling of Macroscopic and Nanoscale In Situ Studies

Since recently, gas-cell transmission electron microscopy allows for direct, nanoscale imaging of catalysts during reaction. However, often systems are too perturbed by the imaging conditions to be relevant for real-life catalyzed conversions. We followed carbon nanofiber growth from NiCu-catalyzed methane decomposition under working conditions (550 °C, 1 bar of 5% H2, 45% CH4, and 50% Ar), directly comparing the time-resolved overall carbon growth rates in a reactor (measured gravimetrically) and nanometer-scale carbon growth observations (by electron microscopy). Good quantitative agreement in time-dependent growth rates allowed for validation of the electron microscopy measurements and detailed insight into the contribution of individual catalyst nanoparticles in these inherently heterogeneous catalysts to the overall carbon growth. The smallest particles did not contribute significantly to carbon growth, while larger particles (8-16 nm) exhibited high carbon growth rates but deactivated quickly. Even larger particles grew carbon slowly without significant deactivation. This methodology paves the way to understanding macroscopic rates of catalyzed reactions based on nanoscale in situ observations

Из истории гидроархеологических исследований на озере Иссык-Куль

Статья посвящена истории археологических исследований на озере Иссык-Куль. На основе архивных данных реконструируются первые попытки изучения дна озера русскими путешественниками и учеными в середине ХIХ века; описывается проект Г.А.Колпаковского по доставке на озеро водолазного оборудования (1871); оцениваются результаты работ экспедиций Д.Ф.Винника и современное состояние дел по изучению подводных памятников озера.Стаття присвячена історії археологічних досліджень на озері Іссик-куль. На основі архівних даних реконструюються перші спроби вивчення дна озера російськими мандрівниками і ученими в середині ХIХ століття; описується проект Г.А.Колпаковського з доставки на озеро водолазного обладнання (1871); оцінюються результати робіт експедицій Д.Ф.Вінника і сучасний стан справ по вивченню підводних пам'ятників озера.The article is devoted to the history of archaeological researches at lake Issik Kul. On the basis of the archived documents the first attempts to investigate the lake bottom by Russian travelers and scientists in the middle of ХIХ age are reconstructed; the G.A.Kolpakovskiy’s project concerning the delivery of diving equipment (1871) to the lake is described; the work results of D.F.Vinnik’s expeditions and modern researches of archaeological artefacts of the lake are assessed

In Situ TEM Study of the Genesis of Supported Nickel Catalysts

In situ transmission electron microscopy is a powerful technique with the unique ability to temporally and spatially resolve nanoscale processes. This can be leveraged in order to obtain insight into the timescales of phenomena occurring during particle growth during the preparation of supported metal catalysts. Thanks to careful experimental design and comparison with ex situ results, the growth of individual nickel nanoparticles from a nickel phyllosilicate catalyst precursor during reduction was studied in situ under atmospheric pressure of 5% H2/Ar at 500 °C and modeled with first-order reaction kinetics. Particles grew rapidly, reaching a final size of between 3.5 and 7 nm within 3-4 min. The vast majority of particles grow as immobile single particles. A two-step particle growth mechanism was sometimes observed wherein two particles nucleating sufficiently close to one another sintered. The resulting particles were not significantly larger (5-7 nm) than those that did not undergo this sintering process. This finding supports the hypothesis that the size of the region from which the nickel species originated determined the particle size

Palladium nanoparticles confined in thiol-functionalized ordered mesoporous silica for more stable Heck and Suzuki catalysts

Palladium nanoparticles of similar size of ~2 nm were synthesized on different silica-based materials, all functionalized with thiol groups i.e., Aerosil-380, SBA-15, plugged SBA-15 and m-MCF. The resulting materials were used to study the influence of the confinement of Pd nanoparticles in a functionalized silica support on the Heck and the Suzuki reactions. In the case of the Heck reaction, for all catalysts it was proven that leached Pd species were responsible for the activity. However, the catalysts based on ordered mesoporous silica were still able to restrict Pd particle growth, giving rise to an enhanced stability. For the Suzuki reaction, stronger alkaline conditions were required and catalysts based on plugged SBA-15 showed a higher stability than those based on SBA-15 and m-MCF, which both collapsed after the first cycle. At almost identical Pd particle size, ordered mesoporous materials enhance stability and particle growth is slowed down but not fully suppressed