In-Plane Spectral Weight Shift of Charge Carriers in YBa2Cu3O6.9YBa_2Cu_3O_{6.9}

The temperature dependent redistribution of the spectral weight of the $CuO_2$ plane derived conduction band of the $YBa_2Cu_3O_{6.9}$ high temperature superconductor (T_c = 92.7 K) was studied with wide-band (from 0.01 to 5.6 eV) spectroscopic ellipsometry. A superconductivity - induced transfer of the spectral weight involving a high energy scale in excess of 1 eV was observed. Correspondingly, the charge carrier spectral weight was shown to decrease in the superconducting state. The ellipsometric data also provide detailed information about the evolution of the optical self-energy in the normal and superconducting states

STATE REGULATION OF ECONOMY AND ENSURING NATIONAL INTERESTS IN THE USA: SOME INSTITUTIONAL ASPECTS

In the article analyzed some institutional aspects of state regulation of the economy on the USA, the structure, status and powers of the Bureau of Industry and Security in the United States Department of Commerce, determined кеу parameters of its influence on strategic industries

CLUSTERS AND INNOVATION CENTRES: IS SPECIAL LOCAL SELF-GOVERNANCE REQUIRED

The territorial aspect of the cluster structure as a potential basis of economics advantage and as an object of the state regulation is analyzed, the approach to innovation as an integral part of the cluster model is determined, issue of direction and limits of state regulation of clusters is raised. The problems of organization of a public government model in cluster territory is discussed, the general approaches to the local self -government regulation and public government in clusters and innovation centres is highlighted

CLUSTERS AND INNOVATION CENTRES: IS SPECIAL LOCAL SELF-GOVERNANCE REQUIRED

The territorial aspect of the cluster structure as a potential basis of economics advantage and as an object of the state regulation is analyzed, the approach to innovation as an integral part of the cluster model is determined, issue of direction and limits of state regulation of clusters is raised. The problems of organization of a public government model in cluster territory is discussed, the general approaches to the local self -government regulation and public government in clusters and innovation centres is highlighted

STATE REGULATION OF ECONOMY AND ENSURING NATIONAL INTERESTS IN THE USA: SOME INSTITUTIONAL ASPECTS

In the article analyzed some institutional aspects of state regulation of the economy on the USA, the structure, status and powers of the Bureau of Industry and Security in the United States Department of Commerce, determined кеу parameters of its influence on strategic industries

Anomalous oxygen isotope effect on the in-plane FIR conductivity of detwinned YBa2Cu316,18^{16,18}O6.9_{6.9}

We observe an anomalous oxygen isotope effect on the a-axis component of the far-infrared electronic response of detwinned YBa2Cu3$^{16,18}$O$_{6.9}$. For $^{18}$O a pronounced low-energy electronic mode (LEM) appears around 240 cm$^{-1}$. This a-axis LEM exhibits a clear aging effect, after one year it is shifted to 190 cm$^{-1}$. For $^{16}$O we cannot resolve a corresponding a-axis LEM above 120 cm$^{-1}$. We interpret the LEM in terms of a collective electronic mode that is pinned by `isotopic defects', i.e. by the residual $^{16}$O in the matrix of $^{18}$O.Comment: 10 pages, 2 figure

Lost pattern complex composition effect on steel casting structure and properties

One of the ways to produce high-quality castings at relatively inexpensive costs is lost foam casting. However, the existing problem of surface carburization due to the burnout of the polystyrene pattern and general contamination of the near-surface layer is one of the factors that hinder the widespread use of this casting method. In order to minimize carburization, it is proposed to use a complex pattern composition. The results of studying the effect of the pattern complex composition and the technological parameters of manufacturing the “Through Cover” casting for the ingot purity and structure are presented

Formation of metallic magnetic clusters in a Kondo-lattice metal: Evidence from an optical study

Magnetic materials are usually divided into two classes: those with localised magnetic moments, and those with itinerant charge carriers. We present a comprehensive experimental (spectroscopic ellipsomerty) and theoretical study to demonstrate that these two types of magnetism do not only coexist but complement each other in the Kondo-lattice metal, Tb2PdSi3. In this material the itinerant charge carriers interact with large localised magnetic moments of Tb(4f) states, forming complex magnetic lattices at low temperatures, which we associate with self-organisation of magnetic clusters. The formation of magnetic clusters results in low-energy optical spectral weight shifts, which correspond to opening of the pseudogap in the conduction band of the itinerant charge carriers and development of the low- and high-spin intersite electronic transitions. This phenomenon, driven by self-trapping of electrons by magnetic fluctuations, could be common in correlated metals, including besides Kondo-lattice metals, Fe-based and cuprate superconductors.Comment: 30 pages, 6 Figure

Charge ordering and magneto-polarons in Na0.82_{0.82}CoO2_2

Using spectral ellipsometry, we have measured the dielectric function of a Na$_{0.82(2)}$CoO$_2$ crystal that exhibits bulk antiferromagnetism with T$_{N}$=19.8 K. We identify two prominent transitions as a function of temperature. The first one at 280 K involves marked changes of the electronic and the lattice response that are indicative of charge ordering in the CoO$_{2}$ layers. The second transition coincides with T$_{N}$=19.8 K and reveals a sizeable spin-charge coupling. The data are discussed in terms of charge ordering and formation of magneto-polarons due to a charge-induced spin-state transition of adjacent Co$^{3+}$ ions

TiOCl, an orbital-ordered system?

We present first principles density functional calculations and downfolding studies of the electronic and magnetic properties of the layered quantum spin system TiOCl. We discuss explicitely the nature of the exchange pathes and attempt to clarify the concept of orbital ordering in this material. An analysis of the electronic structure of slightly distorted structures according to the phononic modes allowed in this material suggests that this system is subject to large orbital fluctuations driven by the electron-phonon coupling. Based on these results, we propose a microscopic explanation of the behavior of TiOCl near the phase transition to a spin-gapped system.Comment: Some figures are compressed, for higher quality please contact the author