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

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

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

Rationale for priority factors of effective cluster development of regional economy

The article discusses the importance of creating a favorable environment to grow regional clusters spanning multiple socio-economic, institutional, natural resource conditions for regional economic development. The aim of the study is to identify factors that have a positive impact on strengthening the strategic positions of the clusters in the regional economy (the cases of 17 emerging clusters in the Perm region serving as an example). Theoretical and applied scientific substantiation of conditions for effective development of the area cluster space is a scientific novelty. The empirical analysis is based on the assessment of clusters weight in the region economy in the years 2002-2014, obtained in the course of processing regional statistics data on employment in different economic activities including the ranking of investment attractiveness compiled by “Expert RA” agency. Using the tools of economic and mathematical modeling with respect to each cluster that are characterized by unique industry specialization, the article identifies the priority development factors, institutional, innovation, labor and natural resources being important factors for most of the analyzed clusters. In terms of the four priority factors directions of cluster development of the Perm region economy are proposed, including proposals for the institutional design of cluster management structures, support of education and research institutions in the region, development of innovative entrepreneurship and strengthening of private initiative in clusters, the conservation of natural resources, and greening of local production. It is shown that the instruments used in the research and results of the factor analysis are of interest to representatives of public authorities who design cluster policies, as well as to experts in the field of cluster analysis; the results can be used to further elaborate programs of cluster development of the region and for the study of cluster initiatives.Статья посвящена обсуждению значимости формирования благоприятной среды выращивания территориальных кластеров, охватывающей многообразные социально-экономические, институциональные, природно-ресурсные условия развития региональной экономики. Целью исследования является идентификация факторов, оказывающих положительное воздействие на укрепление стратегических позиций кластеров в экономике региона (на примере семнадцати формирующихся в Пермском крае кластеров). Научную новизну исследования составляет теоретическое и научно-прикладное обоснование условий эффективного развития кластерного пространства территории. Эмпирический анализ базируется на оценке веса кластеров в экономике региона за 2002-2014 гг., полученной в ходе обработки данных региональной статистики занятости населения по видам экономической деятельности с привлечением экспертных данных рейтинга инвестиционной привлекательности агентства «Эксперт РА». При помощи инструментария экономико-математического моделирования по отношению к каждому кластеру, характеризующемуся уникальной отраслевой специализацией, в статье установлены приоритетные факторы развития, среди которых институциональный, инновационный, трудовой и природно-ресурсный факторы оказались значимыми для большинства анализируемых кластеров. В разрезе четырех приоритетных факторов предложены направления кластерного развития экономики Пермского края, включающие предложения по институциональному оформлению структуры управления кластерами, поддержке образовательных и научно-исследовательских учреждений региона, развитию инновационного предпринимательства и укреплению частной инициативы в кластерах, сбережению природно-ресурсной среды, экологизации местного производства. Показано, что используемый в исследовании инструментарий и результаты факторного анализа представляют интерес для представителей органов государственной власти, разрабатывающих кластерную политику, а также специалистов в области кластерного анализа и могут быть использованы для детализации программ кластерного развития территории и проработки кластерных инициатив.Публикация подготовлена в рамках поддержанного РГНФ научного проекта №16-12-59011

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

The budgeting mechanism in development companies

Relevance of the researched problem is caused by the fact that today there is a requirement for a unique, generalized, theoretically and methodically elaborated budgeting mechanism disaggregating the aims of strategic level to the level of structural units of the company. The aim of article is to develop methodical provisions and practical recommendations to harmonize a budgeting mechanism of development companies on the basis of direct interrelation of current budgeting and strategic objectives of company development. The leading approach to a research of this problem is the classical approach allowing revealing sources and directions of financial resources application of commercial organizations and also ensuring their balance. The main results of a research are the expansion of a budgeting concept as a type of financial planning, the author’s technique of budgeting is suggested that is based on the indicators of assets turnover ratio, sales profitability and return on assets as the main characteristics of activity efficiency of a development company. Materials of the article can be useful in financial management enhancement and forming an effective budgeting mechanism in development companies. © 2016 Kovaleva et al