486 research outputs found
In-Plane Spectral Weight Shift of Charge Carriers in
The temperature dependent redistribution of the spectral weight of the
plane derived conduction band of the 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 YBa2Cu3O
We observe an anomalous oxygen isotope effect on the a-axis component of the
far-infrared electronic response of detwinned YBa2Cu3O. For
O a pronounced low-energy electronic mode (LEM) appears around 240
cm. This a-axis LEM exhibits a clear aging effect, after one year it is
shifted to 190 cm. For O we cannot resolve a corresponding a-axis
LEM above 120 cm. We interpret the LEM in terms of a collective
electronic mode that is pinned by `isotopic defects', i.e. by the residual
O in the matrix of 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
Charge ordering and magneto-polarons in NaCoO
Using spectral ellipsometry, we have measured the dielectric function of a
NaCoO crystal that exhibits bulk antiferromagnetism with
T=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 layers. The second transition coincides with T=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 ions
Spin-controlled Mott-Hubbard bands in LaMnO_3 probed by optical ellipsometry
Spectral ellipsometry has been used to determine the dielectric function of
an untwinned crystal of LaMnO_3 in the spectral range 0.5-5.6 eV at
temperatures 50 K < T < 300 K. A pronounced redistribution of spectral weight
is found at the Neel temperature T_N = 140 K. The anisotropy of the spectral
weight transfer matches the magnetic ordering pattern. A superexchange model
quantitatively describes spectral weight transfer induced by spin correlations.
This analysis implies that the lowest-energy transitions around 2 eV are
intersite d-d transitions, and that LaMnO_3 is a Mott-Hubbard insulator.Comment: 4 pages, 4 figure
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
The study of proteotomic profile of mutton with consideration to the influence of feed combinatorics
The present article is devoted to the search for markers that attest the changes in the protein profile when fattening the lambs with enriched diets, taking into account tissue specificity. The purpose of scientific research was to expand scientific knowledge about the influence of essential trace elements of organic origin in the diet of lambs on the marker-proteins of skeletal muscle tissue, of myocardium and renal cortical substance. The objects of research were the tissues of the m.L.dorsi skeletal muscle, myocardium and cortical substance of the kidneys in lambs of the Edilbaev breed. These lambs received a diet with organic trace elements (iodine, selenium, silicon). To study the effect of microelements in the diets of lambs on change in marker-proteins, we ran the studies of the skeletal muscle, myocardium and cortical substance of the kidneys of lambs, using the method of two-dimensional electrophoresis. When searching for proteins which mark the action of organic additives in the fattening diet of lambs within the tissue of the myocardium and the cortical substance of the kidneys, a number of differences were noted; no pronounced effects were observed in the skeletal muscle. Enrichment of the diet of lambs with selenium derivatives led to a change in the protein composition in the kidneys cortical substance for some isoforms of selenium-containing proteins and related enzymes of the glutathione cycle. Reaction in this process of thermal shock proteins, utilization of aflatoxins and changes in proteins of energy metabolism within mitochondria of kidney cells was also revealed. The determination of functional activity, or immunofermental analysis of glutathione peroxidase 3 count in the blood, can be a promising biomarker for controlling the level of selenium digestion and the count of selenium in blood as a more rapid and cheap method in comparison with the proteomic technologies. And for assessing the rate of digestion and fixation of iodine, it seems promising to determine it via the activity of mitochondrial superoxide dismutase [Mn]. In the myocardium, the effect of digested feed additives mainly affected the mitochondrial apparatus, which changed its functional orientation, with the activation of several other metabolic cycles. These results are prerequisites for obtaining more fundamental data on the effect of diets enriched with essential micronutrients on the molecular mechanisms that take place within the myocardial and kidney tissue of lambs. New data have been obtained on the effect of diets enriched with essential microelements on the molecular mechanisms occurring in the myocardial tissue and cortical substance of the kidneys of goats and sheep. The research results obtained by proteomics methods will be used for modeling and targeted adjustment of diets in order to obtain raw materials with the necessary technological characteristics
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
Studying the binder effect on the properties of briquettes of ferroalloy production waste
The paper shows the results of studies in searching for a binder for briquetting finely dispersed dust (FDD) of ferroalloy production of the Kazakhstan content. The fractional composition and shape of FDD particles were studied. Liquid glass and caustic soda were used as a binder. The research results showed the possibility of using liquid glass as a binder. Experimental briquettes have sufficiently high compressive strength and drop strength, which implies the possibility of their transportation and loading
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