Hydrothermal synthesis of spinel Li1+x Mn2O4 as cathode material for rechargeable lithium battery

Abstract

The hydrothermal synthesis of Li-Mn spinel oxide (Li_1+xMn₂O₄) was undertaken in order to develop high quality, low cost cathode material for a rechargeable lithium battery. In our experiments, γ-MnOOH, LiOH · H₂O and H₂O₂ were used as starting materials to synthesize Li-Mn spinel oxide under hydrothermal conditions of 180-230°C and about 1.0-2.8 MPa. The chemical composition and particle size of the Li_1+xMn₂O₄ is easily controlled in the hydrothermal reaction. The Li_1+xMn₂O₄ produced was characterized by X-ray diffraction, with the spinel phase having a Li/Mn ratio of 0.50-0.60. There is convincing evidence, as a result of this work, that our synthesis process is most suitable for producing high quality cathode material that can be used in a rechargeable lithium battery.     

Development of continuous hydrothermal hot-pressing apparatus

Abstract

A process for continuous hydrothermal hot-pressing has been examined, with the resultant development of a new continuous hydrothermal hot-pressing apparatus. In this study, amorphous siliceous material, slaked lime and pulp fiber were mixed and solidified, at 200°C, to produce a board product. The duration of the hydrothermal hot pressing reaction process was 17 minutes. The bending strength of the board product was high; 11MPa.     

Study on the competition between density waves, singlet, and triplet pairing superconductivity in organic conductors (TMTSF)2X

We study the effect of dimerization of TMTSF molecules and the effect of magnetic field (Zeeman splitting) on the phase competition in quasi one-dimensional organic superconductors (TMTSF)₂X by applying the random phase approximation method. As for the dimerization effect, we conclude that due to the decrease of the dimerization, which corresponds to applying the pressure and cooling, spin and charge density wave states are suppressed and give way to a superconducting state. As for the magnetic field effect, we find generally that spin-triplet pairing mediated by a coexistence of 2k_F spin and 2k_F charge fluctuations can be strongly enhanced by applying magnetic field rather than triplet pairing due to a ferromagnetic spin fluctuations. Applying the above idea to (TMTSF)₂X compounds, a magnetic field induced singlet-triplet transition is consistent with above mechanism in (TMTSF)₂ClO₄.     

Theoretical Analysis of Photon-Mode Super-Resolution Optical Memory Using Saturable Absorption Dye

The possibility of a super-resolution optical memory using a saturable absorption dye mask layer is theoretically discussed. An equation which estimates the transmittance change of the mask layer has been derived. The numerical simulation shows that an efficient super-resolution is performed when the initial optical density of the mask layer is high.     

Super-Resolution with a Photochromic Mask Layer in an Optical Memory

The possibility of a super-resolution optical memory using a photochromic mask layer was theoretically discussed. An equation which estimates the transmittance change of the mask layer was derived. The numerical simulation based on the equation showed that the reflectance increase of the layer by photo-irradiation is nonlinear when the optical density of the layer is high. The nonlinear response decreased the crosstalk in adjacent recording tracks and improved the MTF (modulation transfer function) characteristics, resulting in a higher recording density.     

Catalysis of enantiomeric ester hydrolysis in polymer domains: Catalytic effects of N-decanoyl-histidine and of dipeptide derivatives containing a histidyl residue

The catalytic activities of N-decanoyl-L -histidine and its methyl ester and of dipeptide derivatives containing an L -histidine residue toward the stereoselective hydrolysis of enantiomeric substrates have been studied at pH 7.30 (in 0.01M Bis-tris buffer) and 25°C in the presence of poly(ethyleneimine) derivatives. The dipeptide catalyst revealed greatest stereoselectivity in a quaternized poly(ethyleneimine) derivative. A comparison of catalytic effects on both the rate constants and stereoselectivities of N-decanoyl-L -histidine and its methyl ester elucidates the cooperative effects of carboxyl groups in the polymer domains. The structure of the substrates influenced both the rate constants and stereoselectivities in polymer domains.     

Determination of chemical structures by 1H- and 13C-NMR for thermally degraded linear high density polyethylene

Chemical structures were determined for polymer residues obtained by thermal degradation of a linear high-density polyethylene. Terminal methyl, double bonds (terminal vinyl, trans-vinylene, and vinylidene), and long chain branching were identified by using ¹H- and ¹³C-NMR spectra data. The number of these functional groups per 1000 C was quantified with a relative error of about 10%.