Growth and electronic structure of graphene on semiconducting Ge(110)

The direct growth of graphene on semiconducting or insulating substrates might help to overcome main drawbacks of metal-based synthesis, like metal-atom contaminations of graphene, transfer issues, etc. Here we present the growth of graphene on n-doped semiconducting Ge(110) by using an atomic carbon source and the study of the structural and electronic properties of the obtained interface. We found that graphene interacts weakly with the underlying Ge(110) substrate that keeps graphene's electronic structure almost intact promoting this interface for future graphene-semiconductor applications. The effect of dopants in Ge on the electronic properties of graphene is also discussed.Comment: submitted on 06.04.201

Local electronic properties of the graphene-protected giant Rashba-split BiAg2_2 surface

We report the preparation of the interface between graphene and the strong Rashba-split BiAg$_2$ surface alloy and investigatigation of its structure as well as the electronic properties by means of scanning tunneling microscopy/spectroscopy and density functional theory calculations. Upon evaluation of the quasiparticle interference patterns the unpertrubated linear dispersion for the $\pi$ band of $n$-doped graphene is observed. Our results also reveal the intact nature of the giant Rashba-split surface states of the BiAg$_2$ alloy, which demonstrate only a moderate downward energy shift upon the presence of graphene. This effect is explained in the framework of density functional theory by an inward relaxation of the Bi atoms at the interface and subsequent delocalisation of the wave function of the surface states. Our findings demonstrate a realistic pathway to prepare a graphene protected giant Rashba-split BiAg$_2$ for possible spintronic applications.Comment: text and figures; submitted on 30.12.201

Расчет на прочность сварного уторного шва резервуара РВС-30000

The surface structure and electronic properties of ultrathin MgO layers grown on epitaxial Fe(110) films were investigated at room temperature by means of electron diffraction, Auger electron spectroscopy, scanning tunneling microscopy, and spin-resolved photoelectron spectroscopy. The spin polarization at the Fermi level (EF) of the Fe(110) film decreases sharply with increasing thickness of the MgO layer. This behavior arises from the formation of a thin FeO layer at the MgO(111)/Fe(110) interface, as revealed by structural and spectroscopic investigations. The strong attenuation of the intrinsic spin polarization is qualitatively attributed to the scattering of spin-polarized electrons at the unoccupied d-orbitals of Fe2+

Влияние метеорологических параметров на годовой тренд радиационного фона приземной атмосферы

The surface and interface structure as well as the electronic properties of thin epitaxial Fe3O4(111) films prepared by in situ oxidation of thin Fe(110) films grown on Al2O3(1120) substrates using a Mo(110) buffer layer were investigated by low-energy electron diffraction (LEED), scanning tunneling microscopy (STM),transmission electron microscopy (TEM), and spin-polarized angle-resolved photoemission spectroscopy (SPARPES). The annealing of Fe(110) films at 700 °C in an O2 atmosphere leads to the formation of epitaxial Fe3O4(111) films. Atomically resolved STM images of the Fe3O4(111) surface show a hexagonal symmetry with 6 Å periodicity. Well-controlled interface properties at the Fe3O4(111)/Fe(110) and Fe(110)/Mo(110) interfaces were confirmed by TEM. A high spin polarization value of about 2(6065)% was found near the Fermi energy EF at room temperature by means of SPARPES with a photon energy of hv=21.2 eV. The electronic structure and spin polarization are compared to the corresponding values recently found on epitaxial Fe3O4(111) films grown on W(110) single-crystal substrates

Технологические решения для строительства разведочной вертикальной скважины глубиной 3310 метров на нефтяном месторождении (Тюменская область)

Объектом ВКР служит разведочная вертикальная скважина глубиной 3310 метров на нефтяном месторождении. Целью данной работы является – спроектировать технологическое решения для бурения вертикальной разведочной скважины глубиной 3310 метров на нефтяном месторождении Тюменской области. Для достижения поставленной цели были поставлены следующие задачи: 1.Спроектировать конструкцию скважины. 2.Спроектировать процессы углубления скважины. 3.Спроектировать процессы закачивания.The object of the WRC is an exploration vertical well with a depth of 3310 meters in an oil field. The purpose of this work is to design a technological solution for drilling a vertical exploration well with a depth of 3310 meters at an oil field in the Tyumen region. To achieve this goal, the following tasks were set: 1. Design the well structure. 2. Design the well deepening processes. 3. Design well completion processes. 4. Consider vibration dampener-calibrator. 5. Design pumping processes

Structural and electronic properties of graphene nanoflakes on Au(111) and Ag(111)

We investigate the electronic properties of graphene nanoflakes on Ag(111) and Au(111) surfaces by means of scanning tunneling microscopy and spectroscopy as well as density functional theory calculations. Quasiparticle interference mapping allows for the clear distinction of substrate-derived contributions in scattering and those originating from graphene nanoflakes. Our analysis shows that the parabolic dispersion of Au(111) and Ag(111) surface states remains unchanged with the band minimum shifted to higher energies for the regions of the metal surface covered by graphene, reflecting a rather weak interaction between graphene and the metal surface. The analysis of graphene-related scattering on single nanoflakes yields a linear dispersion relation E(k), with a slight p-doping for graphene/Au(111) and a larger n-doping for graphene/Ag(111). The obtained experimental data (doping level, band dispersions around EF, and Fermi velocity) are very well reproduced within DFT-D2/D3 approaches, which provide a detailed insight into the site-specific interaction between graphene and the underlying substrate

Выбор оптимального метода повышения нефтеотдачи на Новопортовском нефтегазоконденсатном месторождении (ЯНАО)

В работе проведен анализ современных методов увеличения нефтеотдачи. Выполнен анализ применяемых мероприятий, направленных на увеличения нефтеотдачи в рамках Новопортовского месторождения. Предложена технология увеличения нефтеотдачи, показана положительная эффективность применения технологии смешивающихся вытеснений.The analysis of modern methods of enhanced oil recovery is carried out. The analysis of the measures applied to increase oil recovery within the Novoportovskoye field has been carried out. The technology of enhanced oil recovery is proposed, the positive efficiency of the application of the technology of miscible displacement is shown

Development of a three-phase mathematical model of the catalytic cracking feedstock hydrotreating

Integration of mathematical models to the oil refining industry allows predicting the product composition and properties, as well as optimizing the process technological parameters without significant material and time costs. This paper describes an improved mathematical model of the vacuum distillate hydrotreating, taking into account presence of three phases in the system