1,720,986 research outputs found
Effetto del drogaggio con ioni Sb3+ sul comportamento dello spinello di manganese in celle al litio.
No full textFactor affecting the stabilization of the Mn Spinel capacity upon storing and cycling at high temperatures.
No full textDoped and undoped Mn spinels have been evaluated at 55 degrees C in terms of capacity losses upon cycling and storage. The influence of such factors as doping, electrolyte nature, voltage range and constant- or floating-potential storage have been evaluated. Spinels of composition Li1.02M0.05Mn1.95O4 (M = Ga or Cr) exhibit fade rates of 0.15 to 0.20 mAh/g cycle vs. 0.28 mAh/g cycle for the undoped spinel. This reduction may still be unsatisfactory from a practical standpoint, but it is enhanced by two different approaches: (i) storing a cell for some days at 55 degrees C in, e.g., LiBF4-EC/PC; (ii) making a double substitution in the spinel, e.g., with Ga and Cr. The first approach brings the ab.e rate to 0.07 mAh/g cycle for both Ga-doped (2.5 mol %) and undoped spinel, whereas the second one allows a reduction to 0.05 mAh/g cycle, that is less than 0.05%/cycle. These rates of capacity loss are the lowest reported thus far at 55 degrees C. By properly tuning the Li, Ga, and Cr content of the spinel, it seems possible to have simultaneously good average capacities (similar to 110 mAh/g in 100 cycles) and limited fade rates at 55 degrees C
Experimental determination of BEDT-TTF+ electron-molecular vibration constants through optical microreflectance
No full textPHYS. REV.
Pressure dependence of site-CDW amplitude in MX chains and the role of electron-phonon coupling
No full textReference force field and charge-density wave amplitude of mixed-valence halogen-bridged Pt complexes
No full textElectronic and Structural Characterization of A Charge-transfer Crystal With Strong Electronic Correlations Through Infrared and Raman-spectroscopy - Tmpd-tcnqf4
No full textThe electronic and structural characterization of the title charge transfer (CI) complex is carried out mainly by the exploitation of the infrared powder spectrum and its temperature dependence from room temperature to 15 K as well as of the Raman powder spectrum at 15 K. The infrared spectrum shows that the complex has a fully ionic electronic ground state (ρ≂1) and the analysis of the spectroscopic effects due to the radical electron–intramolecular vibration interactions reveals a structure built up of segregated stacks of TMPD and TCNQF4. Moreover, this analysis shows that the TCNQF4 stacks are nonregular in the whole studied temperature range, whereas, by lowering temperature, the TMPD stacks undergo a phase transition from a regular to a nonregular structure with onset at about 180 K. The effective on‐site electronic correlation parameter, the hopping integral, and the magnetic gap of both stacks in the nonregular phase are estimated by adopting a cluster model made up of a dimeric unit to describe the stacks and by comparison with known materials. On the same basis, the temperature dependence of the hopping integrals is also estimated. The collected information, considered in the light of the Peierls–Hubbard model, suggests that TMPD–TCNQF4 can be considered a compound with strong electronic correlations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
