Synthesis and Na+ Ion Conductivity of Stoichiometric Na3Zr2Si2PO12 by Liquid-Phase Sintering with NaPO3 Glass.

Sodium super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) with the advantages of the high ionic conductivity, stability and safety is one of the most famous solid-state electrolytes. NZSP, however, requires the high sintering temperature about 1200 °C and long sintering time in the conventional solid-state reaction (SSR) method. In this study, the liquid-phase sintering (LPS) method was applied to synthesize NZSP with the use of NaPO3 glass with a low glass transition temperature of 292 °C. The formation of NZSP was confirmed by X-ray diffraction analyses in the samples obtained by the LPS method for the mixture of Na2ZrSi2O7, ZrO2, and NaPO3 glass. The sample sintered at 1000 °C for 10 h exhibited a higher Na+ ion conductivity of 1.81 mS/cm at 100 °C and a lower activation energy of 0.18 eV compared with the samples prepared by the SSR method. It is proposed that a new LPE method is effective for the synthesis of NZSP and the NaPO3 glass has a great contribution to the Na+ diffusion at the grain boundaries.

Enhanced rate capabilities in a glass-ceramic-derived sodium all-solid-state battery.

An all-solid-state battery (ASSB) with a new structure based on glass-ceramic that forms Na2FeP2O7 (NFP) crystals, which functions as an active cathode material, is fabricated by integrating it with a ß″-alumina solid electrolyte. Two important factors that influence the rate capability of this ASSB were optimised. First, the particle size of the precursor glass powder from which the NFP crystals are formed was decreased. Consequently, the onset temperature of crystallisation shifts to a lower temperature, which enables the softening of NFP crystals and their integration with ß″-alumina at a low temperature, without the interdiffusion of different crystal phases or atoms. Second, the interface between the ß″-alumina solid electrolyte and cathode active materials which consisted of the NFP-crystallised glass and acetylene black used as a conductive additive, is increased to increase the insertion/release of ions and electrons from the active material during charge/discharge processes. Thus, the internal resistance of the battery is reduced considerably to 120 Ω. Thus, an ASSB capable of rapid charge/discharge that can operate not only at room temperature (30 °C) but also at -20 °C is obtained. This technology is an innovative breakthrough in oxide-based ASSBs, considering that the internal resistance of liquid electrolyte-based Li-ion batteries and sulphide-based ASSBs is ~10 Ω.

Structural origin of high-density Gd2O3-MoO3-B2O3 glass and low-density ß'-Gd2(MoO4)3 crystal: a study conducted using high-energy x-ray diffraction and EXAFS at high temperatures.

In this study, the short- and medium-range ordering of 21.25Gd2O3-63.75MoO3-15B2O3 glass (GM15B glass) was studied at temperatures ranging from 297 K to above the crystallization temperature. This was achieved using extended x-ray absorption fine structure and high-energy x-ray diffraction analyses to elucidate the structural origin of the higher glass density (d) as compared to that of precipitated crystals, i.e. GM15B glass with d = 4.762 g cm-3 and ß'-Gd2(MoO4)3 crystal with d = 4.555 g cm-3, and the self-powdering phenomenon in GM15B glass. The bond lengths in the short-range order, i.e. Gd-O, Mo-O, and Gd-Mo in GM15B, were extremely similar to those in the ß-phase; Gd-Gd and Mo-Mo bonds in Gd-O-Gd and Mo-O-Mo, respectively, were not found. The distance between the Gd-Gd pairs in Gd-O-Mo-O-Gd in GM15B glass, r(Gd-Gd) = 6.19 Å, was considerably smaller than that in ß-Gd2(MoO4)3 crystals (6.71 Å) in the crystallized glass at 808 K. This indicates that the glass had a more packed structure than did the precipitated crystals. The probable origin of the self-powdering phenomenon in GM15B glass was the large expansion of the structure during crystallization, which is due to the formation of an open structure with long Gd-Gd pairs and varying bond angles.

Patterning of two-dimensional planar lithium niobate architectures on glass surface by laser scanning.

Two-dimensional planar LiNbO(3) (LN) crystal architectures are patterned on the surface of Li(2)O-Nb(2)O(5)-B(2)O(3)-SiO(2) glass by continuous wave ytterbium YVO(4) fiber laser (wavelength: 1080 nm) irradiations, in which lasers are scanned continuously with narrow steps (pitches: 0.3 and 0.5 microm) and thus with overlaps of laser irradiated parts. For the planar LN crystals (area: 50 microm x 100 microm) patterned by laser scanning with a power of 0.9 W and a speed of 7 microm/s, it is demonstrated from polarized micro-Raman scattering spectra and azimuthal dependence of second harmonic intensities that the c-axis orientation of LN crystals is established along the laser scanning direction. The present study proposes that the laser irradiation technique gives us uniform LN crystal films on the glass surface.

Canine DNA array as a potential tool for combining physiology and molecular biology.

The combining of molecular biology and physiology is essential for the further development of cardiovascular medicine, and DNA microarray is a useful tool for assessing multiple gene expressions. A canine DNA microarray has been designed and tested. Approximately 60 cardiovascular-related genes were cloned from newly developed canine cDNA libraries and spotted on slides. Using the arrays, the gene expression profiles of canine myocardium in were analyzed 2 protocols: (1). ischemic myocardium by 50% reduction of the coronary blood flow, and (2). necrotic myocardium caused by coronary artery ligation. Three hours after 50% flow reduction, cardiovascular-related genes, including ecto-5'-nucleotidase, endothelin-1, PAI-1, and AT receptors, exhibited rapid alteration and there were many more altered genes than with the complete coronary occlusion. Irreversible ischemic damage without necrosis more strongly affected gene expressions in surviving myocardium than in fatally damaged myocardium. The canine DNA microarray is a useful tool for assessing the precise molecular events following changes in the pathophysiological conditions of the heart.