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261.
M. Piana M. Arrabito S. Bodoardo A. D'Epifanio D. Satolli F. Croce B. Scrosati 《Ionics》2002,8(1-2):17-26
Solid State Reaction was employed to prepare phospho-olivines LiMPO4 (where M=Fe, Co) as pure phase and LiNiPO4 in presence of foreign phases, as cathodic materials for lithiumions batteries. The relationship between structural, morphological
and electrochemical properties were investigated in the case of LiFePO4. Structural investigation has been carried out by means of X-ray powder diffraction (XRPD) and Rietveld refinement. The influence
on the morphology of annealing temperature, different flowing gas mixture and addition of ascorbic acid during the synthesis,
has been analysed via scanning electron microscopy. The electrochemical cycling performances on LiFePO4 showed to be positively affected by the modifications of the experimental conditions. Cyclic voltammetry showed a good reversibility
during insertion-extraction mechanism, in particular in presence of additives. LiCoPO4 and LiNiPO4 are interesting as high voltage cathode materials for Li-ion batteries and have been taken into account, but their electrochemical
operating conditions are still to be optimised. In the case of LiNiPO4 it is very difficult to obtain, by solid state synthesis, suitable purity powders, having a grain size small enough to exploit
it usefully as cathodic material for Li-ion cells.
Paper presented at the 8th EuroConference on Ionics, Carvoeiro, Algarve, Portugal, Sept. 16 – 22, 2000. 相似文献
262.
F. Farid 《Linear and Multilinear Algebra》2002,50(3):223-239
An upper bound for the number of components of the numerical range of matrix polynomials is established. We also establish a necessary condition and a sufficient condition for the connectedness of the numerical range of a quadratic selfadjoint matrix polynomial. The boundary of the numerical range of linear matrix polynomials is also considered. 相似文献
263.
V. F. Klimkin 《Technical Physics》2002,47(9):1106-1111
Methods for analyzing statistical distributions of the breakdown delay time are generalized. A statistical approach is used to study electric breakdown in n-hexane in a 2.1-MV/cm quasi-uniform electric field at a pulse duration of ∼5×10−8 s. Two different mechanisms for the anode breakdown are shown to coexist and compete with each other. One of them incorporates the “bubble” stage, whereas the other one is related to ionization in the liquid itself. It is found that the weaker influence of the external pressure on the pulsed electric strength of liquids in the nanosecond range is caused by a transition to the ionization mechanism for the anode breakdown at elevated pressures. 相似文献
264.
F. D. Saccone C. E. Rodrí guez Torres F. H. S nchez O. Gutfleisch 《Physica B: Condensed Matter》2002,320(1-4):312-315
In the present work, a quantitative analysis of the phase compositions by Mössbauer effect spectroscopy of solid and conventional hydrogen disproportionated Pr13.7Fe80.3B6.0 and Pr13.7Fe63.5Co16.7Zr0.1B6.0 alloys was carried out. Significant amounts of intermediate borides t-Fe3B and Pr(Fe, Co)12B6 were detected after solid hydrogen disproportionation treatment in Pr13.7Fe80.3B6.0 and Pr13.7Fe63.5Co16.7Zr0.1B6.0 alloys, respectively. After conventional hydrogenation–disproportionation–desorption–recombination treatment these phases were not detected and in no case residual Pr2Fe14B-phase was found. It was observed that the amount of intermediate borides after disproportionation can be correlated with the degree of texture after recombination at various temperatures. 相似文献
265.
We have investigated the low-lying collective states and electromagnetic transitions in 94Mo within the framework of the interacting boson model. The influence of model parameters on the energy levels and electromagnetic properties has been investigated. The analysis of the obtained results and the parameter values predict that the 23+state is the lowest mixed symmetry state with pure F = Fmax - 1 in this nucleus. The calculated results predicate that the 25+ (two-Q-phonon) mixed symmetry state is closed to the J = 2+ at 2.870 MeV in the experimental data, and the 2.965 MeV state is the lowest mixed symmetry with J = 3+. 相似文献
266.
267.
A. F. Ivanov 《Ukrainian Mathematical Journal》1989,41(8):903-906
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 41, No. 8, pp. 1054–1058, August, 1989. 相似文献
268.
269.
F. Vlker 《Optics & Laser Technology》1991,23(6):331-334
An alexandrite-laser rod was actively Q-switched in the transversal fundamental mode at λ = 758 nm with an double crystal KD*P Pockels cell. Pulse width, pulse energy and optical pulse delay (the build-up time of the photon field in the resonator) were measured as functions of pumping energy, rod temperature and reflectivity of the output coupling mirror. As the laser gain of alexandrite strongly depends on temperature, the pulse width and pulse energy were also investigated as functions of the temperature of the active material. A comparison of experimental data with theory was made. 相似文献
270.
Summary We report on neutron emission in palladium and titanium electrolitically charged with deuterium. The detection of neutrons
is observed after thermal treatment of the electrode. In the hypothesis that neutrons came from cold fusion processes, we
estimate a fusion rate as high as 1.3·10−21 fusions/deuteron pair/second. 相似文献