Novel polyphenylene and polythiophene derivatives having N,N′-diphenyl-1,4-phenylenediamine units (PP-PDA and PT-PDA) were synthesized. The electronic conductivity of PT-PDA was dramatically enhanced by one-electron oxidation of the PDA unit due to the injection of a cation radical to the main chain from the PDA unit. The electrochemical analysis of the model compounds revealed the carrier injecting to the main chain is based on the electron communication between intramolecular PDAs.

Zn was electrodeposited at 120°C from two kinds of Lewis basic 1-ethyl-3-methylimidazolium bromide (EMIB)-zinc bromide (70 : 30 mol%) binary molten salts containing water at levels of 400 ppm and less than 10 ppm. Smooth layers of silver-colored Zn were electrodeposited at cathodic current densities of less than 100 A m⁻², whereas smooth gray Zn layer were electrodeposited at cathodic current densities greater than 150 A m⁻². The molten salt with a water content of less than 10 ppm was superior to the molten salt with a water content of 400 ppm in cathodic current efficiency, smoothness, and metallic luster. As for the EMIB-ZnBr₂-ethylene glycol (EG) ternary molten salt, with a water content of 30 ppm, the cathodic current efficiencies of the smooth and silver-colored Zn electrodeposits were all 100%, even at a current density as high as 300 A m⁻², for salts with both an EMIB/ZnBr₂ molar concentration ratio of 2/1∼3/1 and with an EG content of 30∼75 mol%.

The ac impedance spectroscopy was applied to dye-sensitized solar cells with TiO₂ or Nb₂O₅ as the semiconductor electrode. It was found that the impedance spectra consisted of three or four semicircles in the Nyquist representation. The arc with a characteristic frequency of a few hundred Hz was attributable to the electron transport between the semiconductor particles or within the particles, the arc at a few Hz to the electron transport at the electrode/dye/electrolyte interface, and the arc at the frequency in the order of 10⁻¹ Hz to the reduction of the electrolyte at the Pt electrode/electrolyte interface. The resistance of the arc at a few Hz decreased as the amount of the dye adsorbed on the TiO₂ electrode and the irradiation intensity increased. When the Nb₂O₅ particles with large BET surface area were used as the electrode, the internal resistance of the solar cell was lowered; especially the shrinkage of the arcs in diameter at a few hundred Hz and a few Hz was significant.

Activated carbon has high power density, but has limited specific capacity. To increase the capacity of activated carbon, ruthenium oxide was loaded into coal-based activated carbon by suspending the activated carbon in an aqueous RuCL solution followed by neutralization. Although the BET surface area of the activated carbon decreased upon ruthenium oxide loading compared to that of the starting material, its capacitance increased. The maximum capacity obtained in this study was 324 F g⁻¹ for activated carbon loaded with 3.2 wt% ruthenium, an increase of about 25%. This unexpected large increase is considered to be due to an introduction of pseudocapacitance of ruthenium oxide and a new mesopore formation by oxidation of activated carbon during the heating process of the composite to improve the pore utility for double layer capacitance.

The electrochemical impedance of various crevice electrodes has been calculated by a transmission line model using matrix. Inside of the crevice was divided into 300 parts, and the solution resistance, the charge transfer resistance, and the capacitance of electric double layer were assumed as the function of the position in the crevice. It takes approximately 10 min to calculate one spectrum of the impedance by the desk-top computer. The impedance shows frequency dispersion due to the current distribution in the high frequency range. The experimental impedance of artificial crevice electrodes was in agreement with the calculated results. The current distribution, which originates by the frequency and the position in the crevice, can be obtained in the course of the computer simulation.

The ultrasonic washing appliance used by professionals shows high cleaning performance in removing stains and spots from clothes. However, the machine system with high cleaning performance requires high electric power, and is large and heavy. We developed a portable ultrasonic washing machine for the common user. The conditions of the ultrasonic washing machine are as follows (1) the frequency of the oscillator (a bolt-clamped Langevin-type transducer) is 50 kHz, (2) the vibrator yields amplified vibration of the oscillator due to the unique shape of metal blocks (Al), (3) the oscillation circuit adjusts the phase to the waveform of voltage and electric current. Our product had the same cleaning effect as that of the professional washing appliance. It is powered by four dry batteries (size AA), and is very light in weight and compact.

Anode discharge electrolysis has been conducted with a molybdenum anode and a LiCl-KCl-KSCN system under 1 atm of Ar at 723 K. A discharge was generated between the melt and the anode whose tip was positioned above the bath surface. After anode discharge electrolysis, black powder was obtained from the melt. From the results of XRD, SEM, EPMA and XPS, the powder obtained was identified to be MoS₂ nano particles. In the same manner, when anode discharge electrolysis was conducted with a tungsten anode, WS₂ particles were obtained.