3,276 research outputs found
Oxygen non-stoichiometry and defect structure of LaMn1-zCuzO3+δ
The quantitative model analysis of the defect structure of copper doped lanthanum manganites LaMn1-zCuzO3+δ (z = 0.05 and 0.1) was performed. In the framework of the model, the independent course of the three reactions of defect formation, including the electronic exchange between manganese and copper, completion of a lattice by the absorption of oxygen and the disproportionation
of manganese was considered. It is shown that the increase in the dopant content leads to a change in the dominant electronic process. This is reflected in the lock and disproportionation and leads to the increase in the concentration of holes and decrease the concentration of electrons localized on the manganese atoms
Ultrafast Collective Dynamics in the Charge-Density-Wave Conductor KMoO
Low-energy coherent charge-density wave excitations are investigated in blue
bronze (KMoO) and red bronze (KMoO) by femtosecond
pump-probe spectroscopy. A linear gapless, acoustic-like dispersion relation is
observed for the transverse phasons with a pronounced anisotropy in
KMoO. The amplitude mode exhibits a weak (optic-like) dispersion
relation with a frequency of 1.67 THz at 30 K. Our results show for the first
time that the time-resolved optical technique provides momentum resolution of
collective excitations in strongly correlated electron systems.Low-energy
coherent charge-density wave excitations are investigated in blue bronze
(KMoO) and red bronze (KMoO) by femtosecond
pump-probe spectroscopy. A linear gapless, acoustic-like dispersion relation is
observed for the transverse phasons with a pronounced anisotropy in
KMoO. The amplitude mode exhibits a weak (optic-like) dispersion
relation with a frequency of 1.67 THz at 30 K. Our results show for the first
time that the time-resolved optical technique provides momentum resolution of
collective excitations in strongly correlated electron systems.Comment: 10 pages, 4 figure
Institutional and organizational features of cross-border cargo traffic in the post-soviet space integration terms. Part I
The article covers the technical, technological, institutional, and organizational barriers of cross-border transportation of cargo. The study uses an institutional approach as a methodological alternative to other approaches. The study touches on institutional and organizational problems of border crossing checkpoints arrangement, the consequences of the application of unified transport documents and the introduction of electronic communication forms. Particular attention is paid to the analysis of demonstrative actions and the daily practice of reducing the time of customs procedures and reducing transaction costs of cross-border cargo traffic. Herewith it is indicated that the most effective way to improve the efficiency of cross-border transportation of cargo suggests simultaneous implementation of technical and institutional innovations. Emphasis is placed on identifying the institutional and organizational features of the international road transportation of cargo, in particular, the problems of the evolution of the guaranteed customs duties payment institute, the permission system in the implementation of cross-border cargo traffic. The fact that the state support of national entrepreneurs requires a mechanism to ensure the parity of Russian and foreign carriers, at least in the field of cargo transportation for state needs, with the involvement of credit resources of government-linked banks is highlighted. It is underlined that the first step towards improving the institutional environment of international road transportation should envisage the elimination of all informal (shadow) relations in this sphere. The article identifies institutional features of cargo transportation in specific areas such as deliveries by road to China through Kazakhstan, and the challenges and prospects for the use and development of transit potential of Kaliningrad Region. The article shows institutional and organizational characteristics of combined transportation in cross-border traffic. The article concludes that the development of cross-border transportation of cargo and the implementation of transport and transit potential of EAEU member states may and should become a powerful source of income for business entities, budgets of all levels and households, as well as the driving force of industrial and technological upgrading and institutional and organizational evolution of economic systems of the countries and integration associations.The article has been prepared with the support of the Russian Foundation for Basic Research (Project № 15-06-06939 a «Modelling the cyclical evolution of mutual influence of the national transport system and the state of the markets of goods (services), labor and capital in terms of integration and global instability»)
Redshifts and Luminosities for 112 Gamma Ray Bursts
Two different luminosity indicators have recently been proposed for Gamma Ray
Bursts that use gamma-ray observations alone. They relate the burst luminosity
(L) with the time lag between peaks in hard and soft energies, and the
spikiness or variability of the burst's light curve (V). These relations are
currently justified and calibrated with only 6 or 7 bursts with known red
shifts. We have examined BATSE data for the lag and V for 112 bursts. (1) A
strong correlation between the lag and V exists, and it is exactly as predicted
from the two proposed relations. This is proof that both luminosity indicators
are reliable. (2) GRB830801 is the all-time brightest burst, yet with a small V
and a large lag, and hence is likely the closest known event being perhaps as
close as 3.2 Mpc. (3) We have combined the luminosities as derived from both
indicators as a means to improve the statistical and systematic accuracy when
compared with the accuracy from either method alone. The result is a list of
112 bursts with good luminosities and hence red shifts. (4) The burst averaged
hardness ratio rises strongly with the luminosity of the burst. (5) The burst
luminosity function is a broken power law, with the break at L = 2x10^{52}
erg/s. The luminosity function has power law indices of -2.8+-0.2 above the
break and -1.7+-0.1 below the break. (6) The number density of GRBs varies with
red shift roughly as (1+z)^(2.5+-0.3) between 0.2<z<5. Excitingly, this result
also provides a measure of the star formation rate out to z~5 with no effects
from reddening, and the rate is rising uniformly for red shifts above 2.Comment: 13 pages, 4 figures, submitted to ApJLet
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