Buncher of electron linac-injector for a synchrotron

The application of RF buncher-accelerators for obtaining the short electron bunches is rather known. Their design varies. Linear accelerators with high-current pulsed beams at energy more than 30 MeV are mainly used as injectors into synchrotrons at modern accelerating complexes. The beam should be previously prepared as series of bunches for injection to obtain stable and effective accelerating regime. In this case RF electron sources would be appropriate for use at the input of a linear accelerator. Such preparing the beam allows one to achieve an effective beam capture into the accelerating regime of linear accelerator for each of the bunches, as well as synchronized operation of the complex with decreased level of radiation background

Dynamics of false vacuum bubbles in Brans-Dicke theory

We study the dynamics of false vacuum bubbles in the Brans-Dicke theory of gravity by using the thin shell or thin wall approximation. We consider a false vacuum bubble that has a different value for the Brans-Dicke field between the inside false vacuum region and the outside true vacuum region. Within a certain limit of field values, the difference of field values makes the effective tension of the shell negative. This allows new expanding false vacuum bubbles to be seen by the outside observer, which are disallowed in Einstein gravity.Comment: 29 pages, 20 figure

Radioheliograph observations of microwave bursts with zebra structures

The so-called zebra structures in radio dynamic spectra, specifically their frequencies and frequency drifts of emission stripes, contain information on the plasma parameters in the coronal part of flare loops. This paper presents observations of zebra structures in a microwave range. Dynamic spectra were recorded by Chinese spectro-polarimeters in the frequency band close to the working frequencies of the Siberian Solar Radio Telescope. The emission sources are localized in the flare regions, and we are able to estimate the plasma parameters in the generation sites using X-ray data. The interpretation of the zebra structures in terms of the existing theories is discussed. The conclusion has been arrived that the preferred generation mechanism of zebra structures in the microwave range is the conversion of plasma waves to electromagnetic emission on the double plasma resonance surfaces distributed across a flare loop.Comment: 18 pages, 7 figure

Insertion of short hepatitis virus A amino acid sequences into poliovirus antigenic determinants results in viable progeny

AbstractIn an infectious poliovirus cDNA construct, the determinant encoding antigenic epitope N-Agl (in a loop located between two β-strands in polypeptide VP1) was altered by site-directed mutagenesis, to be partially similar with the determinants for presumptive epitopes in polypeptides VP1 or VP3 of hepatitis A virus (HAV). The modified constructs proved to be infectious. However, another construct, in which the same locus encoded a ‘nonsense’ and a relatively hydrophobic amino acid sequence, exhibited no infectivity. These data showed the feasibility of the insertion of foreign sequences in a specific antigenically active locus of the poliovirus icosahedron, and suggest some limitations with respect to the sequences to be ‘transplanted’

Spectral Measurement of Photon Emission from Individual Gold Nanoparticles Using Scanning Tunneling Microscopy

The light emission spectra of individual Au nanoparticles induced by a scanning tunneling microscope (STM) have been investigated. Two-dimensional ensembles of tunnel-coupled Au particles were prepared by thermal evaporation onto a native oxide silicon wafer in ultrahigh vacuum (10 – 9 mbar). Our STM measurements show a single peak at photon energy 1.6 eV in the tunneling mode and two peaks at 2.2 eV (connected with the Mie plasmon) and 1.45 eV (a new peak which was not discussed in literature before) in the field emission mode

Comissioning of the linear accelerator-injector at the TNK facility

The industrial storage facility has been developed and manufactured at the Budker INP SB RAS. It contains an 80 MeV electron linear accelerator-injector and two electron storage rings: the lesser 450 MeV booster ring and the main 2.5 GeV storage ring. In 2002, the work on the accelerator assembling was begun. On December, 25 this year the accelerator was started up, and the current at the linear accelerator output was obtained. The linear accelerator schematic together with a description of the 6 meter long accelerating DAW structure which operates at 2.8 GHz, are presented in the paper. The first results of the accelerator start-up are as follows: the accelerated electron current of ~50 mA with the energy of ~55...60 MeV.Технологічний накопичувальний комплекс був спроектований і виготовлений у ІЯФ ім. Г.І. Будкера СВ РАН. Він містить у собі інжектор–лінійний прискорювач електронів з енергією до 80 МеВ і два накопичувачі електронів: малий накопичувач–бустер на енергію 450 МеВ і основний накопичувач на енергію 2.5 ГеВ. Приводяться функціональна схема лінійного прискорювача й опис конструкції прискорюючої структури із шайбами і діафрагмами довжиною 6 м, що працює на частоті 2.8 ГГц.Представлено перші результати запуску прискорювача: отриманий прискорений струм електронів ~50 мА з енергією ~(55...60) МеВ.Технологический накопительный комплекс был спроектирован и изготовлен в ИЯФ им. Г.И. Будкера СО РАН. Он включает в себя инжектор–линейный ускоритель электронов с энергией до 80 МэВ и два накопителя электронов: малый накопитель–бустер на энергию 450 МэВ и основной накопитель на энергию 2.5 ГэВ. Приводятся функциональная схема линейного ускорителя и описание конструкции ускоряющей структуры с шайбами и диафрагмами длиной 6 метров, работающей на частоте 2.8 ГГц. Представлены первые результаты запуска ускорителя: получен ускоренный ток электронов ~50 мA с энергией ~(55...60) МэВ

The "In Situ" Research of the Synthesis of NiMoO4

The formation of the crystal structure of the NiMoO4 high temperature phase in the solid phase reaction NiO+α-MoO3→β-NiMoO4 at 600 C has been "in situ" studied with the high temperature synchrotron technique. We have performed the measurements of the Extended X-ray Absorption Fine Structure (EXAFS) and the X-ray Absorption Near Edge Structure (XANES) at the K-edge of Ni atom in during the -niMoO4synthesis. The analysis of the XANES data and the Fourier transformants of the EXAFS data has led us to the conclusion that at the initial stage of synthesis the nearest oxygen surrounding of Ni atoms in the final production reaction has got an unique geometry that differs from the octahedral oxygen surrounding of Ni atoms in the both structures of NiO and β-NiMoO4. At the initial stage of the β-NiMoO4 synthesis there is not the final product of the synthesis, but the formation of the β-NiMoO4 crystal structure takes place essentially later, contrary to how it has been considered so far. We have concluded that at the original stage of the β-NiMoO4 synthesis the some intermediate phase is formed that is characterized with the low concentration of nickel and the low symmetrical geometry for the nearest oxygen surrounding of Ni atoms

Influence of Geodynamic Processes on Reservoir Properties of Geological Environment (on the Example of the Romashkino Field)

A significant contribution to the structure of the hydrocarbon deposits can be made by fracturing, which is in the active state under the external stresses relative to the Earth (the lunar-solar gravitational action, the total rotational field of the Earth’s stresses, etc.). On the example of comparing the results of system-geodynamic interpretation with reservoir properties of the Bobrikovian, Timanian and Pashian horizons of the Romashkino field using mathematical-statistical analysis, it has been shown that geodynamic activity significantly affects the reservoir properties. Improvement of reservoir productivity is noted in the areas of mutual overlap of geodynamically active zones of dislocations (DAZD) of various orders and strike, which is recommended to be taken into account both in exploration and development of hydrocarbon fields. Consideration of the geodynamic situation, carried out using the results of system-geodynamic interpretation, will allow the most rational use of various methods of oil extraction at operation sites. The results of system-geodynamic zoning should be used in solving a wide range of oil and gas exploration and operational problems, where the development of fractured zones is important. They can be used both for the search and exploitation of hydrocarbon deposits in conventional carbonate and terrigenous reservoirs, and in non-conventional reservoirs, where the main reservoir properties are determined by fractures