Direct modulation of negative glow type laser, which utilizes the negative glow for laser pumping, was investigated. We proposed a unique method for this aim to use a grid, which is inserted in the cathode dark space, thereby to control the cathode fall in potential. Expected results were obtained by this means. The conclusions obtained from this investigation are summarized as follows.
(1) High voltage glow discharge in the range of 1kV was obtained, the V-I characteristics being freely controlled by controlling the grid potential.
(2) The principle of this triode system can be clearly explained by a series connection of two bulbs. The fundamental principle is to use the obstructed discharge.
(3) The mechanism of V-I control was explained using a model proposed and cathode fall theory.
(4) Expected modulation characteristics were obtained in negative glow type He-Cd⁺ laser.

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A primitive LDV system without Bragg cells and analog demodulator is applied to measure the size and the charge of indivisual particles. Charged particles suspended in a steady air flow are fed into an ac electric field, where two laser beams intersect to form a stationary fringe. The light signal emitted from the particle by diffraction is recorded, and its wave form is directly analysed by a personal computer to give information on the amplitude and the phase of the particle oscillation. The information can be converted into the relaxation time and the mobility of the particle, and therefore the equivalent size and the charge of the particle can be obtained. An oblique air flow to the fringe planes may be used to distinguish the polarity of the charge.
The experimental results show that the sizes of DOP particles from a conventional aerosol generator of the vibrating orifice type, which generates mono-disparsed particles in the size range between 1 to 2μm in radius, can be measured very accurately. Further, the results show also that the particles possess a constant and high positive charge (1.5×10^-15C/particle) regardless of the particle sizes. To reveal possible limitations in the proposed method, the measuring system is simulated. The results indicate feasibility of the present method if the amplitude of the particle is greater than the fringe spacing at an adequate frequency to give reasonable phase lag.

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The radiation from low pressure Hg-Ar afterglow was examined by applying the technique of time-resolved spectroscopy. It was found that the intensity of the 2, 537A resonance line exhibited the initial decay attributed to the well-known resonance radiation imprisonment, followed by a declination of much longer decay time constant. The spectral lines of n³D_3.2.1→6³P_2.1.0 and n³S₁→6³P_2.1.0 transitions exhibited a complicated behavior which is characteristic of recombination radiation: The intensity of these lines exhibited an initial rapid decay and a following increase, and after passing through a maximum it decayed at a slower constant rate. It was also found to increase with increasing vapor pressure of mercury and in proportion to the square of the peak current of the pulsed discharge. The series limit continuum radiation which would arise from the radiative recombination, however, was not observed.
It is shown that, based on the decay curves of the afterglow radiation and the kinetics of the recombination reactions Hg⁺+Hg+Ar=Hg₂⁺+Ar Hg₂⁺+e=Hg∗₂=Hg∗+Hg Hg∗=Hg+hν we can determine the ambipolar diffusion constant and the rate constant of conversion from atomic to molecular ion.

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In order to construct a frequency filter for water waves, an equivalent electric circuit analogous to a rectangular channel, which is considered as the standard structure, is analyzed. Features of propagation of shallow water waves in the channel show just the same properties as TE or TM electromagnetic wave transmitting in a space limited by two parallel infinite conducting plates. Namely, the rectangular channel shows the characteristics of high-pass filter for shallow water waves fundamentally. In the wave transmission region, however, it has band-pass characteristics with frequency, although they depend on several parameters of the channel dimension and wave mode. Also in the case of deep water waves, the same features as in the above case, such as the essential high-pass and the band-pass characteristics in the transmission region, are obtained. More detailed properties, however, are somewhat or quite different between both cases.
By utilizing the property of the equivalent electric circuit, a desired wave filter can be provided by series or parallel combination of such channels. A lumped element constant K-type filter is designed, and the experimental result of frequency responce of the filter coincides with the theoretical calculation.

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Electrical conduction in polyimide films was measured at high temperatures under various kinds of atmospheres. Currents were measured for a long time with a very low frequency voltage of 0.001Hz in the temperature range of 160-220°C. The current measured in an atmosphere of oxygen reveals a smaller value than that in a vacuum. On the contrary, in the atmosphere of argon gas or nitrogen gas, the larger current was observed than that in the vacuum. Besides, a good re- producibility was observed in the phenomena. While the activation energies evaluated from the results measured in argon and nitrogen gases show the same magnitude as in the vacuum, the energy evaluated from the results measured in the oxygen gas shows the smaller value. The pressure dependence that the current observed in the argon gas is approximately proportional to the square root of the pressure might suggest a possibility of the relationship between the production of hydrogen gas due to the dissociation of molecules and the ionic conduction observed.

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Breaking arc durations and differences between the mass of a contact before and after an experiment, that is a quantity of metal erosion and transfer (QMET), were measured in Ag-Pd alloy contacts. The experiments were tried in air at some conditions of voltage, current and opening speed. The characteristics of arc durations and QMET studied how to change due to metal mixing ratios.
In a practical Ag 40 wt%contact, the arc duration was not specially longer, and the loss was not more than the others. In Ag 90 wt%contact, the arc duration had a great tendency to be longer at some conditions, and then the loss was much. The arc duration of Ag 20 wt%had a tendency to become long with operations. The characteristics of arc duration and QMET were different due to two ways of fixing a columnar contact from one side to a holder and from two side. The curves of QMET were zero-crossed, and there were the mixing ratio that the QMET became zero for the one of the electrodes.
This paper might suggested some way of a design of electrode for heat produced in the Ag-Pd alloy contacts and the possibility of zero QMET.

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