Solute–solvent interactions of oligo(m-benzamide)s in N,N-dimethylacetamide

Studies on solute–solvent interactions of oligo(m-benzamide)s in N,N-dimethylacetamide (DMA) have been carried out. The enthalpies of solution have been measured for oligo(m-benzamide)s and oligo(m-phenylene)s in DMA and benzene. Contributions of enthalpies of cavitation and dispersion interaction to the enthalpy of transfer from benzene to DMA, ΔH_tr (Ben → DMA), have been examined for oligo(m-phenylene)s. A considerable contribution of excess enthalpy, ΔH_E (Ben → DMA), to ΔH_tr (Ben → DMA) has been found, which increases with the number of benzene rings of the solute. By assuming that ΔH_E (Ben → DMA) of diphenyl (DP) is equal to that of benzanilide (BA) in DMA, the amide hydrogen bond enthalpy of BA in DMA, ΔH estimated by “the pure base method” corrected for the enthalpies of cavitation and dispersion interaction. The ΔH value has been given by the following expression including the unknown solubility parameter of BA, δ^BA: The evaluation of δ^BA has resulted in the conclusion that ?ΔH is smaller than 10.9 kJ mol^?1. Moreover, ΔH_tr (TMU → DMA) for oligo(m-benzamide)s has been examined. It has been shown that the amide hydrogen bonding ability of DMA is lower than that of TMU. The linearity of the plot of ΔH_tr (TMU → DMA) against the number of amide bonds in the molecule has been explained by the increase in hydrogen bond enthalpies with the number of amide bonds in the molecule.     

Spatial resolution of an incoherent-to-coherent converter using bismuth germanium oxide

An incoherent-to-coherent converter is constructed with a bismuth germanium oxide crystal. Several experiments are carried out with emphasis on the spatial resolution. It is found that the line width of the read-out image is approximately proportional to the logarithm of the write-in pulse duration, and that longer exposures cause the read-out image to deteriorate sooner. Several ways to increase the spatial resolution of the converter are discussed.     

Examination of wet coating and co-sintering technologies for micro-SOFCs fabrication

Preparation conditions to obtain a dense electrolyte layer on a micro-tubular electrode support were investigated using wet coating and subsequent co-firing techniques. An anode-supported micro-tubular SOFC with 1.5 mm diameter was successfully fabricated by careful control of the co-sintering process of electrolyte/anode support laminates. The densification of the electrolyte layer deposited on the support surface was greatly affected by the shrinkage of tubular support during the co-sintering process. Support shrinkage above 15% was found to produce a fully densified electrolyte layer on the anode support. In contrast, the use of an anode support with shrinkage below 10% constrained gadolinium-doped ceria (GDC) sintering, resulting in a poorly densified GDC microstructure. Finally, we obtained a micro-tubular cell composed of a dense GDC and a porous (La,Sr)(Co,Fe)O₃–GDC multi-layered structure on a NiO–GDC micro-tubular anode support. The cell, with a dense and ≈15 μm thick GDC electrolyte layer, was electrochemically evaluated in a temperature range from 450 to 550 °C. This micro-tubular cell with an electrode length of 6.3 mm showed a power density above 0.1, 0.2 and 0.4 W/cm² at 450, 500 and 550 °C, respectively, in wet H₂ fuel flow.     

The reaction of propargyl alcohol with amines a novel route to aminopropanones and 2-methylquinoxaline

Propargyl alcohol reacts with a variety of amines in the presence of zinc acetate and cadmium acetate at reflux temperatures for 8–20 h to give aminopropanones in fairly good yields. o-Phenylenediamine gives 2-methylquinoxaline.     

Polymer solutions and entropic-based systems for double-stranded DNA capillary electrophoresis and microchip electrophoresis

We give an overview of recent development of low-viscosity polymer solutions and entropic trapping networks for double-stranded DNA (dsDNA) separations by conventional capillary electrophoresis and microchip electrophoresis. Theoretical models for describing separation mechanisms, commonly used noncross-linked polymer solutions, thermoresponsive (viscosity-adjustable) polymer solutions, and novel entropic trapping networks are included. The thermoresponsive polymer solutions can be loaded at one temperature into microchannels at lower viscosities, and used in separation at another temperature at entanglement threshold concentrations and higher viscosities. The entropic-based separations use only arrays of regular obstacles acting as size-separations and do not need viscous polymer solutions. These progresses have potential in integration to automated capillary and microfluidic chip systems, enabling better reusability of separation microchannels, much shorter DNA separation times, and higher reproducibility due to less matrix degradation.