Search results for "Lithium"
showing 10 items of 680 documents
Novel group 4b ansa-metallocene complexes with the shortest bridge: [1,1′-isopropylydene-3,3′-di-t.Bu-bis(η5-cyclopentadienyl)] Ti and Zr dichlorides
1997
Abstract Reaction of [1,1′-isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienide)] dilithium with TiCl3, followed by treatment with HCl, and ZrCl4 in various solvent mixtures in the temperature range 0–50°C gives corresponding ansa-metallocene dichlorides as mixtures of the anti/syn-isomers, 1:1. The crystal and molecular structures of three of the four isomers were determined, i.e. rac(anti)-[1,1′-isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienyl)]TiCl2, space group B2/b, rac(anti)-[1,1′-isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienyl)]ZrCl2, space group P212121, and meso(syn)-1,1′-[isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienyl)]ZrCl2, space group P21/n.
Gelled Electrolyte Containing Phosphonium Ionic Liquids for Lithium-Ion Batteries
2018
In this work, new gelled electrolytes were prepared based on a mixture containing phosphonium ionic liquid (IL) composed of trihexyl(tetradecyl)phosphonium cation combined with bis(trifluoromethane)sulfonimide [TFSI] counter anions and lithium salt, confined in a host network made from an epoxy prepolymer and amine hardener. We have demonstrated that the addition of electrolyte plays a key role on the kinetics of polymerization but also on the final properties of epoxy networks, especially thermal, thermo-mechanical, transport, and electrochemical properties. Thus, polymer electrolytes with excellent thermal stability (>
Integrated low drive voltage electro-optic Bragg modulator using a, periodically poled lithium niobate
2017
Periodically poled lithium niobate (PPLN) is currently used for frequency conversions using quasi-phase-matching, thanks to its high nonlinear coefficients and mature poling process. PPLN can also be attractive for electro-optic (EO) applications. Several studies have been conducted on PPLN-based EO deflectors, and recent realizations have lower the required applied voltage under hundred volts [1]. Indeed, for practical EO applications drive voltages as low as 5 V are usually required. For this purpose, we use a recent technique to realize high-quality isolated crystalline film out of LN [2] to implement an EO Bragg deflector with a drive voltage below 10 V. In this work we present an effic…
Low drive voltage electro-optic Bragg deflector using a periodically poled lithium niobate planar waveguide
2016
International audience; An electro-optic Bragg light deflector is demonstrated in a thinned, periodically poled lithium niobate planar waveguide confined between two silica layers on a silicon substrate. More than 97% of diffraction efficiency is obtained with an operating wavelength of 633 nm for the two orthogonal light polarizations with a drive voltage of about 5 V. The temporal electric drift and the response time of the component are also studied.
Etude par analyse thermique différentielle des tranformations de phases sur l'iodate de lithium
1986
International audience; Lithium iodate (LiIO3) exists at room temperature either as hexagonal (alpha) or tetragonal (beta) crystals. Beta-LiIO3 is stable up to the melting point, whereas alpha-LiIO3 is known to undergo phase transitions. We have studied by differential thermal analysis (DTA) the sequence of phase transitions occurring on powders prepared by different processes. An alpha-LiIO3 powder obtained by grinding a single crystal exhibits the well-known transformations alpha-gamma-beta. A powder obtained by fast evaporation of an aqueous solution transforms directly the alpha to the beta and does not exhibit any intermediate gamma phase. Further, DTA investigations point out that the…
Residual Phase Noise Measurement of Optical Second Harmonic Generation in PPLN Waveguides
2017
We report on the characterization, including residual phase noise and fractional frequency instability, of fiber-coupled PPLN non-linear crystals. These components are devoted to frequency doubling 871 nm light from an extended-cavity diode laser to produce a 435.5 nm beam, corresponding to the ytterbium ion electric quadrupole clock transition. We measure doubling efficiencies of up to 117.5 %/W. Using a Mach-Zehnder interferometer and an original noise rejection technique, the residual phase noise of the doublers is estimated to be lower than ${\rm -35\, dBrad^2/Hz}$ at 1 Hz, making these modules compatible with up-to-date optical clocks and ultra-stable cavities. The influence of externa…
Myo-inositol counteracts the vegetalizing effect of lithium on P.lividus embryos
1992
Abstract The vegetalizing effect of LiCl on sea urchins embryos can be counteracted by the addition of myo-inositol. This observation is discussed in connection with similar results recently reported for amphibian embryos.
Lithium adsorption at prismatic graphite surfaces enhances interlayer cohesion
2013
Abstract We use density functional calculations to determine the binding sites and binding energies of Li + at graphene edges and prismatic graphite surfaces. Binding is favorable at bare and carbonyl terminated surfaces, but not favorable at hydrogen terminated surfaces. These findings have implications for the exfoliation of graphitic anodes in lithium-ion batteries that happens if solute and solvent co-intercalate. First, specific adsorption facilitates desolvation of Li + . Second, chemisorption lowers the surface energy by about 1 J m −2 prismatic surface area, and gives graphite additional stability against exfoliation. The results offer an explanation for experiments that consistentl…
Bi2Se3 Nanostructured Thin Films as Perspective Anodes for Aqueous Rechargeable Lithium-Ion Batteries
2022
This research was funded by the European Regional Development Fund Project (ERDF) No. 1.1.1.1/19/A/139. Y.R. acknowledges the support of post-doctoral ERDF project No. 1.1.1.2/VIAA/4/20/694. V.L. also acknowledges the support of “Strengthening of the capacity of doctoral studies at the University of Latvia within the framework of the new doctoral model”, identification No. 8.2.2.0/20/I/006. A.S. acknowledges the support from the Institute of Solid State Physics, University of Latvia, which, as the Center of Excellence, has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
The increase in maternal expression of axin1 and axin2 contribute to the zebrafish mutant ichabod ventralized phenotype.
2014
β-Catenin is a central effector of the Wnt pathway and one of the players in Ca(+)-dependent cell-cell adhesion. While many wnts are present and expressed in vertebrates, only one β-catenin exists in the majority of the organisms. One intriguing exception is zebrafish that carries two genes for β-catenin. The maternal recessive mutation ichabod presents very low levels of β-catenin2 that in turn affects dorsal axis formation, suggesting that β-catenin1 is incapable to compensate for β-catenin2 loss and raising the question of whether these two β-catenins may have differential roles during early axis specification. Here we identify a specific antibody that can discriminate selectively for β-…