Preparation of Lanthanum Nickel Oxide-Coated Ni Sheet Anodes and Their Application to Electrolytic Production of (CF3)3N in (CH3)4NF·4.0HF Melt

A new process for electrolytic production of a perfluorinated compound, (CF₃)₃N, using lanthanum nickel oxide-coated Ni sheet anode in the (CH₃)₄NF·4.0HF melt at room temperature, was developed. Thin films of the lanthanum nickel oxides were prepared on Ni sheets by sol-gel coating method using polyvinlylpyrrolidone(PVP). The main components of the thin films were La₂O₃, LaNiO₃, and La₂NiO₄ at 500, 750 and 1000 °C, respectively. The anode performance in the (CH₃)₄NF·4.0HF melt depends greatly on the main component of the thin film, and the LaNiO₃-coated Ni sheet anode gives the best anode performance. The potential of LaNiO₃-coated Ni sheet anode remains constant at 5.9 V during electrolysis at 20 mA·cm⁻² in the (CH₃)4NF·4.0HF melt for 100 h. This is because LaNiO₃ and NiF₃, and/or Ni₂F₅, the latter of which was formed during electrolysis, in the film give a high electronic conductivity to the surface film during electrolysis. The maximum mole fraction of (CF₃)₃N (21.4%) was obtained at 20 mA·cm⁻² in (CH₃)₄NF·4.0HF melt using the LaNiO₃-coated Ni sheet.     

Debugging methods in recursive structured FORTRAN

A version of structured FORTRAN named STAR is introduced. STAR allows recursive subroutines. Implementation problems such as parameter passing by value and local variable stacking are discussed. The major difficulty in the preprocessor approach is debugging. We claim that execution profiles are strong debugging aids, and demonstrate how to debug a STAR program at source language level with the clue in the profiles plus assertion statements. We make use of a quicksort program as an example.     

Surface structures of synthetic diamonds

Diamond crystals of about 2 mm in size were grown by the temperature gradient method using Ni, Ni-Fe alloy and Fe as solvent metals. Several characteristic patterns were seen on the surfaces of the grown diamonds and were found to correspond to the texture of the quenched solvent metals. A vague vein-like pattern appeared when Ni was used. The surface patterns became finer with the increase of the content of Fe in Ni-Fe alloy, and when 70 wt% Fe-30 wt% Ni alloy was used, very fine dendritic patterns were seen on all of the faces of diamond in accordance with the symmetries of the lattice. The patterns are formed by the precipitation of carbon atoms in the space of the dendrites of the solvent metals during the quenching process. Lamellar patterns and etch pits were seen when Fe was used. The patterns are formed when Fe dissolves the diamond surfaces to produce Fe₃C during the quenching process.     

Nanoliter-sized liquid dispenser array for multiple biochemical analysis in microfluidic devices

We have developed a microdispenser array made of PDMS, in which a number of nanoliter-sized droplets can be accurately dispensed and mixed with the aid of specific channels under pneumatic pressure. In this system, hydrophobic and narrow channels act as a kind of valve and help structural liquid manipulation. Also, by arranging multiple dispensers in parallel, a single injection of liquid becomes sufficient for the preparation of multiple nanoliter-sized aliquots for different reactions. We designed two kinds of microdevices for multiple liquid dispensing and mixing and evaluated their performance and reproducibility, proving them sufficient for quantitative reactions. As a practical application, biochemical analysis of glucose was performed using enzymatic reactions. This liquid dispensing technology can be widely applied in the field of microscale analysis due to its low consumption, small dead volume of reagents and samples, and ease of operation.     

The evaporation and carburization behavior of coated systems of niobium on molybdenum and niobium on titanium

The evaporation, carburization and diffusion behavior of Nb-coated Mo and of Nb-coated Ti were investigated in order to estimate the surface characteristics of the coated systems. Nb layers were formed on Mo by both chemical and physical vapor deposition and on Ti by just physical vapor deposition. From the diffusion behavior, interdiffusion coefficients were obtained at 1860°C, 1980°C and 2080°C for the chemically vapor-deposited Nb/Mo system. From evaporation experiments it was found that simultaneous evaporation of Nb and Mo occured at about 2300°C for thick films of Nb on Mo. For thin films of Nb on Mo, the evaporation of both Nb and Mo was confirmed at 1900°C by ion microprobe analysis of the condensate. For Nb/Ti, rapid diffusion of Nb into Ti and evaporation of Ti similar to the case of Nb-Ti alloys were observed. From the carburization study, it was found that an Nb coating appreciably retards the carburization of Ti and Mo.     

Controlled release of biofunctional substances by radiation-induced polymerization: 1. Release of potassium chloride by polymerization of various vinyl monomers

The release behaviour of a drug from flat circular capsules obtained by radiation-induced polymerization at low temperatures and with different hydrophilic properties has been studied. The effect of various factors on release property was investigated. The release process could be divided into three parts, an initial quick release stage, stationary state release stage and a retarded release stage. Release behaviour in the stationary state was examined using Noyes-Whitney and Higuchi equations. It was shown that the hydrophilic property of polymer matrix expressed by water content was the most important effect on diffusion and release rate. Rigidity of the polymer may also affect diffusivity. The first quick release step could be attributed to rapid dissolution of drug in the matrix surface due to polymer swelling.