МЕТАЛЛИЧЕСКИЕ НАНОПЛЕНКИ НА МОНОКРИСТАЛЛИЧЕСКОМ КРЕМНИИ: РОСТ, СВОЙСТВА И ПРИМЕНЕНИЕ

The metal–silicon thin−film system is not isostructural and furthermore exhibits pronounced interdiffusion and chemical reactions. Therefore the growth of metallic films on silicon leads to a high concentration of defects in the film, especially at its substrate interface. The material also contains stress and a transition layer consisting of melts or compounds (silicides).We have considered theoretical viewpoints and reviewed experimental data on the growth and properties of metallic nanofilms (including multilayered ones) on silicon, and also provided a brief review of their applications. The films consist either of atomic−sized, quabquantum sized and quantum sized layers. We have suggested a low temperature film growth technology based on freezing growing layers during deposition by maintaining a low temperature of the substrate and using an atomic beam with a reduced heat power. The technology uses a specially shaped deposition system in which the distance between the source and the substrate is comparable to their size or smaller. Furthermore, we use a special time sequence of deposition that provides for a reduced substrate surface temperature due to greater intervals between deposition pulses. This growth method of atomically thin films and multilayered nanofilms excludes interdiffusion between the layers, reduces three−dimensional growth rate and relatively increases lateral layer growth rate.Тонкопленочная система металл — кремний является неизоструктурной и, кроме того, характеризуется ярко выраженными процессами взаимодиффузии и химическими реакциями. Поэтому рост металлических нанопленок на кремнии сопровождается высоким уровнем дефектности пленки, особенно ее границы раздела с подложкой. Также присутствуют напряжения и образуется переходный слой, состоящий из сплавов или соединений (силицидов). Рассмотрены теоретические представления и дан обзор экспериментальных результатов по росту и свойствам металлических нанопленок (включая многослойные) на кремнии, а также краткий обзор их применения. Пленки состоят как из атомно−тонких или субквантово−размерных, так и из квантово−размерных слоев. Предложен процесс низкотемпературного роста пленки, основанный на замораживании растущих слоев в процессе осаждения, путем поддержания пониженной температуры подложки и использования атомного пучка с пониженной тепловой мощностью. В этом процессе использована специальная геометрия системы осаждения, в которой расстояние между источником и подложкой сопоставимо или меньше их размеров. Кроме того, применена временнáя последовательность осаждения, которая обеспечивает поддержание пониженной температуры поверхности подложки за счет длительной выдержки между порциями осаждения. Такой рост атомно−тонких пленок и многослойных нанопленок предотвращает взаимодиффузию между слоями, ослабляет трехмерный рост и усиливает по отношению к этим процессам латеральный слоевой рост

Luminescent coordination polymers based on Ca²⁺ and octahedral cluster anions [{M₆Clⁱ₈}Clᵃ₆}²⁻ (M = Mo, W) : synthesis and thermal stability studies

Luminescent coordination polymers (CPs) based of inexpensive stable precursors are attractive materials for applications. Here we report the synthesis and evaluation of the stability and photophysical characteristics of the first examples of phosphorescent CPs based on octahedral molybdenum and tungsten cluster anions. Specifically 1D CP trans-[{Ca(OPPh₃)₄}{{M₆Clⁱ₈}Clᵃ₆}]∞ (M = Mo, W) can be obtained either directly at increased temperature or via intermediate phases [cis-Ca(OPPh₃)₄(H₂O)₂][{M₆Clⁱ₈}Clᵃ₆]∙2CH₃CN that are stable at room-temperature, but convert to the titled CP at temperatures above 100 °C

ИМПАКТНЫЙ КРАТЕР НЕПСКИЙ-1 И ОСАДКИ, ВЫПОЛНЯЮЩИЕ ЕГО НА ПОВЕРХНОСТИ ФУНДАМЕНТА СИБИРСКОЙ ПЛАТФОРМЫ

In the Earth studies, discoveries and investigations of impact craters buried beneath thick sediments are sporadic so far and may still remain inefficient, unless geophysical surveys of the areas of interest are initiated. Such studies can provide useful data to develop the knowledge about cosmic events of the past geological eras, as well as contribute to industrial development of the areas. It is known that an impact crater is filled with layered deposits that create specific sequences and are generally thicker that deposits outside the crater. We have investigated a Precambrian crater located in the southern part of the Nepa-Botuoba anteclise of the Siberian platform. This impact crater called Nepsky-1 was discovered by seismic surveys using the common depth point method (CDPM). In our study, we used the geological and geophysical deep-drilling data of three wells, including gamma-ray and neutron logs and lithological core descriptions. With reference to the concepts of regional geological conditions, we reconstructed the conditions of sedimentation in the study area based on a comprehensive analysis of the structural and textural features of the rocks, and logging and seismic survey data. By processing and interpretation of the CDPM 3D seismic survey data, we obtained the structural images and cross-sections of the impact crater and analysed the thickness of its fill deposits. The Nepsky-1 crater is a bowl-shaped structure with a rim composed of allogenic breccia. In the area around the crater, fault systems are detected. Based on the core sample analysis, we identified the lithological members of the crater and its rim and described them in detail. Active compensation with lacustrine-delta sediments took place in the Nepa period of the late Vendian. By the end of the Tira time, the crater was completely leveled up. In our study, we obtained the first data on the structure of the crater section of the Vendian deposits. Sedimentation in the study area was controlled by the sea level changes. The main terrigenous productive horizons are confined to sandstones that accumulated during the sea level low stand, and found at the bottoms of the lower and upper Nepa subsuites, as well as at the bottoms of the lower and upper Tira subsuites. It is established that the study area was tectonically active in the late Tira time. As a result, the sediments filling the crater were removed to subaerial conditions, and the edges of the allogenic breccia rim were partially destroyed and formed granite breccia outgrowths observed in the rim’s cross-section. We conclude that in the Nepa and Tira times, tectonic vertical movements initiated relatively fast weathering and transportation of the terrigenous material from the adjacent hills into the sedimentation basin. The Nepsky-1 crater gives evidence of meteorite bombing of the Siberian paleocontinent in Precambrian. Finding similar crater structures can be reasonably expected in the study region. Considering the increased thicknesses of crater fill deposits, buried craters are promising potential for discovering oil-source and overlying seal rocks, which is important for petroleum industry.Обнаружение и изучение импактных кратеров, скрытых под многометровой толщей осадочного чехла, носят спорадический характер и не представляются возможными без использования площадной геофизической сьемки. Их исследование является актуальным, так как может пролить свет на космические события, происходившие в прошлые геологические эпохи. Осадки, заполняющие кратер, создают особый тип разреза с увеличенной мощностью по сравнению с таковыми за пределами кратера. Целью исследования является изучение особенностей погребенного кратера докембрийского возраста, впервые обнаруженного при проведении площадных сейсмических работ МОГТ на юге Непско-Ботуобинской антеклизы Сибирской платформы. В ходе работы авторами были использованы геолого-геофизические данные глубокого бурения трех скважин, включающие гамма-каротаж, нейтронный каротаж, литологическое описание керна. В результате комплексного анализа структурно-текстурных признаков пород, каротажных диаграмм и сейсмических данных, с учетом концепций региональных геологических условий, воссозданы условия осадконакопления в исследуемом районе. Структурные построения, анализ мощности разрезов выполнены на основании данных обработки и интерпретации сейсморазведочных работ методом МОГТ 3D. Кратер имеет чашеобразную форму с насыпным валом аллогенной брекчии. Вокруг кратера фиксируются серии разломов. Результаты исследования керна в районе кратера позволили выделить и детально описать пачки кратерного и бортового типа разреза. В непское время позднего венда происходила его активная компенсация озерно-дельтовыми осадками. К концу тирского времени он был полностью снивелирован. Впервые получены данные о строении кратерного разреза вендских отложений. Формирование отложений контролировалось колебанием уровня моря. К песчаникам, накопившимся в этап низкого стояния уровня моря, приурочены основные терригенные продуктивные горизонты: в подошве нижненепской и верхненепской, а также в подошве нижнетирской и верхнетирской подсвиты. Установлено, что в позднетирское время в регионе произошла тектоническая активизация, которая привела осадки кратера к выводу в субаэральные условия и спровоцировала частичное разрушение выступов аллогенной брекчии, которые сформировали выносы гранитной брекчии в бортовом типе разреза. В непское и тирское время, по мнению авторов, имели место тектонические вертикальные движения, которые инициировали относительно быстрое выветривание и транспортировку терригенного материала с прилегающих возвышенностей в бассейн осадконакопления. Обнаруженный кратер свидетельствует о метеоритных бомбардировках Сибирского палеоконтинента в докембрии. Следует ожидать обнаружение данных структур в исследуемом регионе. Образованные кратеры привлекательны повышенной мощностью отложений, наличием потенциальных нефтематеринских пород и покрышек. Выявление кратеров является перспективной задачей нефтегазовой отрасли

Complexes of non-lacunary Keggin- and Dawson-type polyoxometalates with Pb(ii): formation of 1D coordination polymers with different bonding modes

© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.A new coordination polymer based on Keggin-type [SiW12O40]4- and Pb2+ ions, {Pb2(μ2-DMF)2(DMF)8(SiW12O40)} (1a), was prepared by a reaction between H4[SiW12O40] and Pb(NO3)2 in N,N-dimethylformamide (DMF). Varying the crystallization conditions, a complex with a slightly different coordination mode of the {Pb2} unit and solvate composition, {Pb2(μ2-DMF)2(DMF)8(SiW12O40)}·DMF (1b), can be obtained. The complex containing Well-Dawson polyoxoanions, {(Pb(μ2-DMF)3(DMF)6)(Pb(DMF)5)(P2W18O62)}·0.5DMF·1.3H2O (2), was prepared by a similar strategy

Porous Nanocrystalline Silicon Supported Bimetallic Pd-Au Catalysts: Preparation, Characterization, and Direct Hydrogen Peroxide Synthesis.

Bimetallic Pd-Au catalysts were prepared on the porous nanocrystalline silicon (PSi) for the first time. The catalysts were tested in the reaction of direct hydrogen peroxide synthesis and characterized by standard structural and chemical techniques. It was shown that the Pd-Au/PSi catalyst prepared from conventional H2[PdCl4] and H[AuCl4] precursors contains monometallic Pd and a range of different Pd-Au alloy nanoparticles over the oxidized PSi surface. The PdAu2/PSi catalyst prepared from the [Pd(NH3)4][AuCl4]2 double complex salt (DCS) single-source precursor predominantly contains bimetallic Pd-Au alloy nanoparticles. For both catalysts the surface of bimetallic nanoparticles is Pd-enriched and contains palladium in Pd0 and Pd2+ states. Among the catalysts studied, the PdAu2/PSi catalyst was the most active and selective in the direct H2O2 synthesis with H2O2 productivity of 0.5 [Formula: see text] at selectivity of 50% and H2O2 concentration of 0.023 M in 0.03 M H2SO4-methanol solution after 5 h on stream at -10°C and atmospheric pressure. This performance is due to high activity in the H2O2 synthesis reaction and low activities in the undesirable H2O2 decomposition and hydrogenation reactions. Good performance of the PdAu2/PSi catalyst was associated with the major part of Pd in the catalyst being in the form of the bimetallic Pd-Au nanoparticles. Porous silicon was concluded to be a promising catalytic support for direct hydrogen peroxide synthesis due to its inertness with respect to undesirable side reactions, high thermal stability, and conductivity, possibility of safe operation at high temperatures and pressures and a well-established manufacturing process

Genetic Characterization of Hantaviruses Transmitted by the Korean Field Mouse (Apodemus peninsulae), Far East Russia

In an epizootiologic survey of 122 rodents captured in Vladivostok, Russia, antibodies positive for hantavirus were found in Apodemus peninsulae (4/70), A. agrarius (1/39), and Clethrionomys rufocanus (1/8). The hantavirus sequences identified in two seropositive A. peninsulae and two patients with hemorrhagic fever with renal syndrome (HFRS) from the Primorye region of Far East Russia were designated as Solovey and Primorye, respectively. The nucleotide sequences of the Solovey, Primorye, and Amur (obtained through GenBank) sequences were closely related (>92% identity). Solovey and Primorye sequences shared 84% nucleotide identity with the prototype Hantaan 76-118. Phylogenetic analysis also indicated a close relationship between Solovey, Primorye, Amur, and other viruses identified in Russia, China, and Korea. Our findings suggest that the Korean field mouse (A. peninsulae) is the reservoir for a hantavirus that causes HFRS over a vast area of east Asia, including Far East Russia

Production and characterization of a recombinant single-chain antibody against Hantaan virus envelop glycoprotein

Hantaan virus (HTNV) is the type of Hantavirus causing hemorrhagic fever with renal syndrome, for which no specific therapeutics are available so far. Cell type-specific internalizing antibodies can be used to deliver therapeutics intracellularly to target cell and thus, have potential application in anti-HTNV infection. To achieve intracellular delivery of therapeutics, it is necessary to obtain antibodies that demonstrate sufficient cell type-specific binding, internalizing, and desired cellular trafficking. Here, we describe the prokaryotic expression, affinity purification, and functional testing of a single-chain Fv antibody fragment (scFv) against HTNV envelop glycoprotein (GP), an HTNV-specific antigen normally located on the membranes of HTNV-infected cells. This HTNV GP-targeting antibody, scFv3G1, was produced in the cytoplasm of Escherichia coli cells as a soluble protein and was purified by immobilized metal affinity chromatography. The purified scFv possessed a high specific antigen-binding activity to HTNV GP and HTNV-infected Vero E6 cells and could be internalized into HTNV-infected cells probably through the clathrin-dependent endocytosis pathways similar to that observed with transferrin. Our results showed that the E. coli-produced scFv had potential applications in targeted and intracellular delivery of therapeutics against HTNV infections

Photochemistry Of Monochloro Complexes Of Copper(ii) In Methanol Probed By Ultrafast Transient Absorption Spectroscopy

Ultrafast transient absorption spectra in the deep to near UV range (212-384 nm) were measured for the [Cu-II(MeOH)(5)Cl](+) complexes in methanol following 255-nm excitation of the complex into the ligand-to-metal charge-transfer excited state. The electronically excited complex undergoes sub-200 fs radiationless decay, predominantly via back electron transfer, to the hot electronic ground state followed by fast vibrational relaxation on a 0.4-4 Ps time scale. A minor photochemical channel is Cu-Cl bond dissociation, leading to the reduction of copper(H) to copper(I) and the formation of MeOH center dot Cl charge-transfer complexes. The depletion of ground-state [Cu-II(MeOH)(5)Cl](+) perturbs the equilibrium between several forms of copper(II) complexes present in solution. Complete re-equilibration between [Cu-II(MeOH)(5)Cl](+) and [Cu-II(MeOH)(4)Cl-2] is established on a 10-500 ps time scale, slower than methanol diffusion, suggesting that the involved ligand exchange mechanism is dissociative