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31.
Clarke SJ Adamson P Herkelrath SJ Rutt OJ Parker DR Pitcher MJ Smura CF 《Inorganic chemistry》2008,47(19):8473-8486
A series of layered oxychalcogenide and oxypnictide solids is described that contain oxide layers separated by distinct layers, which contain the softer chalcogenide (S, Se, Te) or pnictide (P, As, Sb, Bi) anions. The relationships between the crystal structures adopted by these compounds are described, and the physical and chemical properties of these materials are related to the structures and the properties of the elements. The properties exhibited by the oxychalcogenide materials include semiconductor properties, for example, in LaOCuCh (Ch = chalcogenide) and derivatives, unusual magnetic properties exhibited by the class Sr 2MO 2Cu 2-deltaS 2 (M = Mn, Co, Ni), and redox properties exhibited by the materials Sr 2MnO 2Cu 2 m-0.5 S m+1 ( m = 1-3) and Sr 4Mn 3O 7.5Cu 2Ch 2 (Ch = S, Se). Recent results in the oxychalcogenide area are reviewed, and some new results on the intriguing series of compounds Sr 2MO 2Cu 2-deltaS 2 (M = Mn, Co, Ni) are reported. Oxypnictides have received less recent attention, but this is changing: a new frenzy of research is underway following the discovery of high-temperature superconductivity (>40 K) in derivatives of the layered oxyarsenide LaOFeAs. The early results in this exciting new area will be reviewed. 相似文献
32.
Hilda Sucipto Fumitaka Kudo Tadashi Eguchi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2012,124(14):3484-3487
33.
Sérgio Luis Costa Ferreira Hilda Costa dos Santos Djane Santiago de Jesus 《Analytical and bioanalytical chemistry》2001,369(2):187-190
A procedure is proposed for the separation and determination of molybdenum in iron matrices by a batch process. It is based on the solid-phase extraction of the molybdenum(V) ion as thiocyanate complex on polyurethane (PU) foam. The extraction parameters were optimized. Using 0.20 mol L–1 hydrochloric acid, a thiocyanate concentration of 0.10 mol L–1, 100 mg of polyurethane foam and shaking time of 10 min, molybdenum (5–400 μg) can be separated and preconcentrated from large amounts of iron (10 mg). Desorption was carried out instantaneously by conc. nitric acid or acetone. Distribution coefficients, sorption capacity of the PU foam and coefficients of variation were also evaluated. The effect of some ions on the separation procedure was assessed. Iron(III) should be reduced to iron(II). The proposed procedure was used to determine molybdenum in standard iron matrices such as steel and pure iron. The achieved results did not show significant differences with certified values. 相似文献
34.
The addition of a nonlinear term to the Jaynes-Cummings Hamiltonian induced a nontrivial discrete dynamics for the number of possible transitions of a given order, represented by a Fibonacci series. We describe the physics of the problem in terms of relevant operators which close a semi-Lie algebra under commutation with the Hamiltonian and therefore extending the generalized Bloch equations, already obtained for the linear case, to the nonlinear one. The initial conditions as well as a thermodynamical treatmetn of the problem is analyzed via the maximum entropy principle density operator. Finally, a generalized solution for the time-independent case is obtained and the solution for the field in a thermal state is recovered. 相似文献
35.
Dinah Rosenberg 《International Journal of Game Theory》1998,27(4):577-597
We introduce the dual of a stochastic game with incomplete information on one side, and we deduce some properties of optimal
strategies of the uninformed player.
Received December 1996/Revised version December 1997 相似文献
36.
Dinah Rosenberg Eilon Solan Nicolas Vieille 《Probability Theory and Related Fields》2001,119(3):433-451
We study stopping games in the setup of Neveu. We prove the existence of a uniform value (in a sense defined below), by allowing
the players to use randomized strategies. In constrast with previous work, we make no comparison assumption on the payoff
processes. Moreover, we prove that the value is the limit of discounted values, and we construct ε-optimal strategies.
Received: 10 May 1999 / Revised version: 18 May 2000 / Published online: 15 February 2001 相似文献
37.
38.
Hilda Geiringer 《Monatshefte für Mathematik》1936,43(1):425-434
Ohne Zusammenfassung 相似文献
39.
Abner Cardoso Rodrigues Luis Otavio Sales Ferreira Caboclo Hilda Alicia Cerdeira Edson AmaroJr. Birajara Soares Machado 《The European physical journal. Special topics》2018,227(7-9):883-893
In this paper we present connectivity patterns of evolving large scale epileptic networks. We employed a cross-entropy measure in the frequency domain on EEG signals to infer the networks, before and during episodes of epileptic seizures. This measure allowed us to make a richer portrait about the node interactions on the graph and to identify emergent structures associated with the synchronization of brain activity. Our results points to a more complex scenario of network organization than the synchronized/unsynchronized dichotomy, with two main results: first, showing regions with unsynchronized (or independent) behavior, even during absence seizures, contradicting the concept of hypersynchrony. Furthermore, we explore the cross-entropy fluctuations along the seizure: a group of nodes became more similar over time while another group became more different, showing a complementary behaviour and different local brain activities. These results bring new questions about the spreading and the sustenance of the epileptic seizures and others synchronization phenomena in living systems. 相似文献
40.