Li<Superscript>+</Superscript> ionic conduction properties on NaI doped with a small amount of LiBH<Subscript>4</Subscript>

In the present work, Li⁺ conductor is synthesized via small doping of LiBH₄ into “Li-free” compound (or solid solvent), NaI. The formation of solid solution between NaI and LiBH₄ is confirmed by XRD measurement, and the solubility limit of LiBH₄ exists between 6 to 13 mol%. The value of σ for 15NaI·LiBH₄ (6 mol% LiBH₄) showed 1.7 × 10^?6 S/cm at room temperature, which is comparable to that for LiI. From the plot of log σT vs. 1000/T, an activation energy for Li⁺ conduction in NaI is estimated to be 0.68 and 0.32 eV for heating and cooling cycle, respectively. The results of AC impedance measurement and DC polarization test indicate that Li⁺ plays a major role in ionic conduction in NaI regardless of the slight molar fraction of Li⁺. The present results suggest that the expansion in the material choice for solid solvent and other alkali halides can also work as a base material for Li⁺ ion conductors.     

Preparation and characterization of the ZnO:Al/Fe65Co35/ZnO:Al multifunctional films

The ferromagnetic transparent conducting film is a multifunctional film which has high visible transmittance, low resistivity and room-temperature ferromagnetism, simultaneously. In this article, ferromagnetic transparent conducting ZnO:Al/Fe₆₅Co₃₅/ZnO:Al multilayer films were fabricated by inserting a middle magnetic Fe₆₅Co₃₅ layer into aluminum-doped zinc oxide (ZnO:Al) matrix using a magnetron sputtering apparatus at substrate temperature ranging from room temperature (RT) to 400^∘C. The total film thickness was about 400 nm and the middle Fe₆₅Co₃₅ alloy layer was 4 nm. The influences of substrate temperature (T _s ) on the structural, electrical, optical and magnetic properties of the multilayer films were systemically investigated. The results showed that the microstructure and performance of the composite multilayer films strongly depended on the substrate temperature. The present results also showed that the inserted middle Fe₆₅Co₃₅ alloy thin layer played an important role in providing the RT ferromagnetism and decreasing the resistivity of the multilayer films. Therefore, it is possible to obtain a multifunctional film material with the combination of good optical transparency, high electrical conductivity and RT ferromagnetism.     

Hyperfine fields at nonmagnetic impurities in ferromagnetic GdZn and GdCd

Hyperfine fields at sp impurities in ferromagnetic CsCl type compounds GdZn and GdCd have been measured by NMR method. The impurity hyperfine fields are always negative, indicating the negative polarization of s-like conduction electrons at impurities on the Zn(Cd) sites, and are smaller at the beginning and end of each sp series. This trend of the hyperfine fields is similar to that in Gd metal and is qualitatively understood by the Daniel-Friedel mechanism.     

Regulation of NH-tautomerism in N-confused porphyrin by N-alkylation

A variety of internally N-alkylated N-confused porphyrins were prepared in a stepwise manner through the protection of the reactive peripheral nitrogen atom. NH-Tautomerism in N-confused porphyrins was found to be regulated by N-alkylation, which enabled us to obtain discrete information on two important NH-tautomers of an N-confused porphyrin.     

Mn nuclear magnetic resonance studies in RMn2Ge2 (R = rare earths)

The ⁵⁵Mn NMR in RMn₂Ge₂ (R= La,Nd and Gd) were observed as a function of temperature. In Nd and Gd compounds the ⁵⁵Mn NMR frequencies exhibit anomalous temperature dependences owing the effects of rare earth sublattices. The ordering temperatures of the Nd and Gd sublattices are found to be 30 and 95 K, respectively.     

Self-consistent calculations of the density of 2D electron gas in AlxGa1−xAsGaAs heterointerface as a function of the doping level in n-AlxGa1−xAs layer

Sheet density of two-dimensional electron gas at the Al_xGa_1?xAs heterointerface is calculated self-consistently as a function of doping level in n-Al_xGa_1?xAs layer by taking into account shallow donor level and the DX centers. The results show a good agreement with the experimental results reported by Ishikawa et al. Dingle's rule of the conduction band discontinuity does not agree with the present results but with 0.62 rule proposed recently by Watanabe et al.     

Molecular dynamics study of the liquid-vapor interface of lithium bromide aqueous solutions

The molecular dynamics simulations of the liquid–vapor interface of LiBr aqueous solutions were carried out to investigate the structural and thermophysical properties. As concerns the structural properties, the results of molecular dynamics simulation show that the ions exist in the liquid apart from the surface and this tendency becomes strong as the solute concentration is lowered. This phenomenon is due to the desorption of ion. The calculated values such as density or surface tension agree with experimental ones. As concerns thermophysical properties, the number of water molecules in the bulk gas decreases with an increase of the solute concentration. This result represents the depression of vapor pressure. In addition, in order to investigate the dynamic process of water vapor absorption into LiBr aqueous solution, the molecular dynamics simulation under non-equilibrium condition was carried out. The results show that when the solute concentration is low and the temperature is also low, almost all incident water molecules become trapped at the solution surface and then easily diffuse into the bulk liquid, and when the solute concentration is high and temperature is also high, most incident water molecules become trapped at the solution surface, and the sequent processes are very complicated. Received on 28 September 1998     

Experimental investigation on the heat transfer characteristics of novel rectangle radial microchannel heat exchangers in two-phase flow cooling system for data centers

Journal of Thermal Analysis and Calorimetry - Biobased odd–odd poly(propylene dicarboxylate)s, based on 1,3-propanediol and three odd diacids [i.e., glutaric acid (C5), pimelic acid (C7) or...