804 research outputs found
Features of the historical development and modern reconstruction of sch?nbrunn park in vienna (Austria)
Sch?nbrunn is a palace and park complex of the Baroque period. The ensemble’s formation occurred under the influence of the environment, historical events and national culture. The article is focused on the history of development of the ensemble, its lay-outs and composition peculiarities. The specifics of reconstruction of the park, including separate zones and park plantings, are studied
The problems of modern approaches to creation of the landscape flower gardens in the modern urban space (Minsk)
The article concerns the main prerequisites for cr eation landscape flower gardens in the modern ur-ban space. A research of current trends in landscape improvement of urban areas showed that the flow-er decoration is an integral tool in creating aesthe tically pleasing, comfortable and sustainable spaces in the city. In the flower design of Minsk plain composition using annual ornamental plants is dominated. The analysis of the experience of urban gardening in foreign countries has shown that perennial flowers allow you to create decorative natural plant compositions that do not require significant maintenance during the growing season, as well as more economical to use. Special attention is given to such type of gardening, as a flower garden, which is widespread in the modern tendency landscape design “New wave”. Generally, the results of the research show that landscaped flower gardens are the most promising floral-decorative design of various landscape objects in Minsk. It based on the knowledge of the ecological requirements of perennial plants, peculiar ities of growing certain crops in an urban setting
Beyond Moore's technologies: operation principles of a superconductor alternative
The predictions of Moore's law are considered by experts to be valid until
2020 giving rise to "post-Moore's" technologies afterwards. Energy efficiency
is one of the major challenges in high-performance computing that should be
answered. Superconductor digital technology is a promising post-Moore's
alternative for the development of supercomputers. In this paper, we consider
operation principles of an energy-efficient superconductor logic and memory
circuits with a short retrospective review of their evolution. We analyze their
shortcomings in respect to computer circuits design. Possible ways of further
research are outlined.Comment: OPEN ACCES
Study in the impact of dispersant on paraffin crystallization using the method of dynamic scattering
STRUCTURE FORMATION PROCESS OF HYDRATED PORTLAND CEMENT COMPOSITIONS: NANOSCALE LEVEL CONTROL
Durability of cement-like construction materials, as well as durability of cement stone, depends on their humidity resistance, frost resistance, corrosion resistance. All of these properties depend not only on the composition of the original clinker, but also on structural organization at micro-and nanoscale level of hydrated portland cement compositions. In this research the authors used the method of small-angle neutron scattering to define structural parameters of hydrated portland cement compositions on nanoscale level, distribution of calcium hydrate silicate nanoparticles in size, medium nanoparticles radius, fractal dimension. It is shown, that introduction of modifying nanoadditives into portland cement compositions affects structural parameters of a cement stone. The following nanoadditives were used: of artificial (alpha aluminium oxide, gamma aluminum oxide) and of anthropogenic (carbonate and alumo-alkaline sludges) origin, as well as integrated nanoadditives containing surfactants. The change in structural parameters of portland cement compositions with nanoadditives in the process of hydration is investigated. It is shown that use of nanoadditives allows to control the process of forming the structure of hydrated portland cement composition on the nanoscale level, directly affect the values of structural parameters and, as a result, modify properties of cement stone
Influence of randomly distributed magnetic nanoparticles on surface superconductivity in Nb films
We report on combined resistance and magnetic measurements in a hybrid
structure (HS) of randomly distributed anisotropic CoPt magnetic nanoparticles
(MN) embedded in a 160 nm Nb thick film. Our resistance measurements exhibited
a sharp increase at the magnetically determined bulk upper-critical fields
Hc2(T). Above these points the resistance curves are rounded, attaining the
normal state value at much higher fields identified as the surface
superconductivity fields Hc3(T). When plotted in reduced temperature units, the
characteristic field lines Hc3(T) of the HS and of a pure Nb film, prepared at
exactly the same conditions, coincide for H10 kOe
they strongly segregate. Interestingly, the characteristic value H=10 kOe is
equal to the saturation field of the MN. The behavior mentioned above is
observed only for the case where the field is normal to the HS, while is absent
when the field is parallel to the film. Our experimental results suggest that
the observed enhancement of surface superconductivity field Hc3(T) is possibly
due to the not uniform local reduction of the external magnetic field by the
dipolar fields of the MN.Comment: to be published in Phys. Rev.
Evidence for two-dimensional nucleation of superconductivity in MgB
According to the crystal structure of MgB and band structure
calculations quasi-two-dimensional (2D) boron planes are responsible for the
superconductivity. We report on critical fields and resistance measurements of
30 nm thick MgB films grown on MgO single crystalline substrate. A linear
temperature dependence of the parallel and perpendicular upper critical fields
indicate a 3D-like penetration of magnetic field into the sample. Resistivity
measurements, in contrast, yield a temperature dependence of fluctuation
conductivity above T which agrees with the Aslamazov-Larkin theory of
fluctuations in 2D superconductors. We consider this finding as an experimental
evidence of two-dimensional nucleation of superconductivity in MgB.Comment: 5 RevTex pages, 3 PostScript Figures ZIPed in archive Sidoren.zip.
Submitted to EuroPhys. Lett. December 3, 200
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