Method of Determination of Natural Frequencies and Forms of Nonlinear Vibrations for Layered Cylindrical Panels

The technique of finding a finite number of first natural frequencies for geometrically nonlinear vibrations of layered elongated cylindrical panels at discrete consideration of components is proposed and verified. The influence of the radius of curvature on the natural frequencies of three- and five-layered panels is investigated. The dependence between the volume of filler three-layer panels and the lowest natural frequency has been established

Synthesis of Nanosilver in Plasma-Liquid Microdischarge System

This paper presents the results of investigation of the plasma-liquid system with the secondary discharge supported by atmospheric pressure microdischarge in the vortex Ar flow. The plasma treated fluids were aqueous solutions of AgNO3. The microplasma discharge was powered by a DC supply. The plasma channel behaviour was characterized by photo/video recording, also plasma was studied using emission spectroscopy technique. The working liquid and firm products created after the treatment were studied also

Fermi surfaces of single layer dielectrics on transition metals

Single sheets of hexagonal boron nitride on transition metals provide a model system for single layer dielectrics. The progress in the understanding of h-BN layers on transition metals of the last 10 years are shortly reviewed. Particular emphasis lies on the boron nitride nanomesh on Rh(111), which is a corrugated single sheet of h-BN, where the corrugation imposes strong lateral electric fields. Fermi surface maps of h-BN/Rh(111) and Rh(111) are compared. A h-BN layer on Rh(111) introduces no new bands at the Fermi energy, which is expected for an insulator. The lateral electric fields of h-BN nanomesh violate the conservation law for parallel momentum in photoemission and smear out the momentum distribution curves on the Fermi surface.Comment: 14 pages, 6 figures, 1 table, 1 equation, Accepted for publication in the Special Surface Science issue in honor of Gerhard Ertl's Nobel Priz

Generation of silver nanoparticles in a plasma-liquid system with a secondary discharge supported by a rotating gliding discharge

Generation of silver nanoparticles in plasma-liquid system with secondary discharge that supported by rotating gliding discharge was investigated in work. Parameters of liquids after plasma treatment were investigated by absorption spectroscopy method. The Atomic Force Microscope (AFM) was used to determine the particle sizes obtained during the processing.Досліджувалась генерація наночастинок срібла в плазмоворідинній системі з вторинним розрядом, що підтримується обертовим ковзним розрядом. Параметри рідини після плазмової обробки досліджувались методом абсорбційної спектроскопії. Атомно-силовий мікроскоп (AСM) використовувався для визначення розмірів частинок, які були отримані під час обробки.Исследовалась генерация наночастиц серебра в плазможидкостной системе с вторичным разрядом, поддерживаемым вращающимся скользящим разрядом. Параметры жидкостей после плазменной обработки исследовались методом абсорбционной спектроскопии. Атомно-силовой микроскоп (AСM) использовался для определения размеров частиц, полученных во время обработки

First-principles study of hydrogen storage over Ni and Rh doped BN sheets

Absorption of hydrogen molecules on Nickel and Rhodium doped hexagonal boron nitride(BN) sheet is investigated by using the first principle method. The most stable site for the Ni atom was the on top side of nitrogen atom, while Rh atoms deservers a hollow site over the hexagonal BN sheet. The first hydrogen molecule was absorbed dissociatively over Rh atom, and molecularly on Ni doped BN sheet. Both Ni and Rh atoms are capable to absorb up to three hydrogen molecules chemically and the metal atom to BN sheet distance increases with the increase in the number of hydrogen molecules. Finally, our calculations offer explanation for the nature of bonding between the metal atom and the hydrogen molecules, which is due to the hybridization of metal d orbital with the hydrogen s orbital. These calculation results can be useful to understand the nature of interaction between the doped metal and the BN sheet, and their interaction with the hydrogen molecules

In Situ Observations during Chemical Vapor Deposition of Hexagonal Boron Nitride on Polycrystalline Copper.

Using a combination of complementary in situ X-ray photoelectron spectroscopy and X-ray diffraction, we study the fundamental mechanisms underlying the chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation and growth of h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, on the Cu surface during exposure to borazine. A Cu lattice expansion during borazine exposure and B precipitation from Cu upon cooling highlight that B is incorporated into the Cu bulk, i.e., that growth is not just surface-mediated. On this basis we suggest that B is taken up in the Cu catalyst while N is not (by relative amounts), indicating element-specific feeding mechanisms including the bulk of the catalyst. We further show that oxygen intercalation readily occurs under as-grown h-BN during ambient air exposure, as is common in further processing, and that this negatively affects the stability of h-BN on the catalyst. For extended air exposure Cu oxidation is observed, and upon re-heating in vacuum an oxygen-mediated disintegration of the h-BN film via volatile boron oxides occurs. Importantly, this disintegration is catalyst mediated, i.e., occurs at the catalyst/h-BN interface and depends on the level of oxygen fed to this interface. In turn, however, deliberate feeding of oxygen during h-BN deposition can positively affect control over film morphology. We discuss the implications of these observations in the context of corrosion protection and relate them to challenges in process integration and heterostructure CVD.P.R.K. acknowledges funding from the Cambridge Commonwealth Trust and the Lindemann Trust Fellowship. R.S.W. acknowledges a research fellowship from St. John’s College, Cambridge. S.H. acknowledges funding from ERC grant InsituNANO (no. 279342), EPSRC under grant GRAPHTED (project reference EP/K016636/1), Grant EP/H047565/1 and EU FP7 Work Programme under grant GRAFOL (project reference 285275). The European Synchrotron Radiation Facility (ESRF) is acknowledged for provision of synchrotron radiation and assistance in using beamline BM20/ROBL. We acknowledge Helmholtz-Zentrum-Berlin Electron storage ring BESSY II for synchrotron radiation at the ISISS beamline and continuous support of our experiments.This is the final version. It was first published by ACS at http://pubs.acs.org/doi/abs/10.1021/cm502603

Subtle Nanostructuring of the Au/Ru(0001) Surface

Abstract We report on a scanning tunneling microscopy (STM) study of the nanostructuring of the Au/Ru(0001) thin film system for the cases of 5 monolayers (ML) and 9 ML of Au deposited at 300 K and subsequently annealed at 1050 K. A new laterally periodic superstructure is observed at the surface of the 9 ML film, which is essentially a rippling in height of the surface atomic layer with the magnitude up to 0.03 ± 0.01 nm and in-plane periodicity of 4.6 ± 0.4 nm, the long-range order being absent

Geometrically nonlinear free transversal vibrations of thin-walled elongated panels with arbitrary generatrix

The algorithm for finding a finite number of the first values of natural frequencies and forms of geometrically nonlinear free transverse vibrations of thin-walled elongated panels with arbitrary generatrix is proposed and verified. Under normal coordinate quadratic the approximation of displacements is used. Along the tangential coordinates used one-dimensional finite elements. The discrete variation problem is built. For its solving the perturbation method is applied. The numerical results are compared with previously obtained by other authors

Oxygen-etching of h-BN/Ru(0001) nanomesh on the nano- and mesoscopic scale

The stability of the recently discovered b-BN/Ru(0001) nanomesh is of crucial importance for potential applications as a nanotemplate. In particular, thermal stability in oxygen environment is important for nanocatalysis applications. We report here on the etching experiments of the h-BN layer by molecular oxygen exposure at elevated temperatures. This process is studied both by scanning tunneling microscopy (STM) on a microscopic scale and with in situ low energy electron microscopy (LEEM) on the mesoscopic scale. Temperature thresholds are determined for the microscopic (600 degrees C) and the mesoscopic (750 degrees C) etching processes for O-2 pressures up to 1 x 10(-6) mbar. Submonolayer amounts of An deposited on the h-BN/Ru(0001) nanomesh improve considerably the stability of the h-BN nanomesh against etching by O-2

Reduction of Technological Power Consumption at the Expense of Rational Transfer of Reactive Power in Power Engineering System

The paper presents definition of the problem and description of the algorithm concerning optimum planning of reactive power of electric power stations of the power engineering system.The algorithm of the problem solution is developed with due account of corresponding limitations on allowable reactive power limits at some electric power stations