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Absolute values of the surface charge densities at the top and bottom of a capillary plate (CP) placed on a powered electrode were evaluated under the influence of pulse-modulated very high frequency (40 MHz) plasma. The peak-to-peak voltage at the top and bottom of the CP was measured using a high-voltage probe; this voltage was carefully calibrated, removing the influence of probe impedance. Based on the peak-to-peak voltage, the capacitances of the sheath and the CP were evaluated. Based on the average voltage, the surface charge density was evaluated for the plasma-on and off phases. A charge density of the order of 10−5 C m−2 was obtained at the bottom of the CP. Furthermore, two important observations were made during the plasma-off phase, namely: conservation of the surface charge density at the bottom of the CP and presence of the residual negative surface charge at the top of the CP.

Charging and discharging behavior of high aspect-ratio (AR) hole capillary plate (CP) exposed to a pulse-modulated very high frequency (VHF) capacitively-coupled plasma is investigated. From an equivalent circuit model, time-dependent charge density on the bottom of the CP is quantitatively evaluated. AR of the CP plays very important role for the charging current, although the discharge current is dominated by the leakage current of the CP. Importance of electron current flowing into the CP bottom during the VHF pulse-on phase is suggested at higher self-bias voltages.

In order to improve the performance of the floor heating system, it is very important to investigate how the heat loss is caused and how the energy consumption of the system could be reduced. Therefore, the heat loss from a hot water floor heating system was investigated in a residential house in Japan. Through the investigation process, several improvements were made in the heating system. To know the effect of the improvements, the upward/downward heat flows from the hot-water panel and the heat loss from the piping of the floor heating system were calculated. In result, insulating the piping and attaching the insulation below the floor improved the upward heat flow rate from the panel. However closing the ventilation openings hardly improved the rate of the upward heat flow from the panel. Although insulating the pipe and attaching the insulation below the floor improved the upward heat flow, heat loss from the piping was still high. To reduce the heat loss from the floor heating system, it is much effective to insulate the piping, compared with the improvement of the insulation and structure of the floor.