In recent years, considerable attention has been given to the increase of temperature and densities of plasmas. The quasi-optical methods for the measurements of high temperature plasmas are reviewed. The topics discussed are: ion temperature, electron temperature, electron density.
Observations of viscosity measurement by means of the drawing sphere method led the authors to notice that the motion of the sphere can scarcely satisfy the equivelocity conditions on which the basic equation of this method is based. This fact accounts for the errors and ques-tions assosiated with this method. To analyze the causes of non-equivelocity motion of the system, including both the balance and sphere hung by a wire, the authors carried out a mathe-matical analysis and introduced new equations which satisfactorily represent the various actual motions. The techiniques to apply the equations to the actual measurement procedure were also studied. As a result, the range of measurable viscosity values of this viscometer and the accuracy of them have been remarkably improved.
With regard to the print-through phenomenon of magnetic tape, a new high-sensitivity automatic recording torque meter was constructed and a method of measuring the magnetic after-effect of the magnetic powder was studied. The samples were cubic-shaped ferromagnetic oxide powders of 0.046μ to 0.105μ mean diameter. The magnetic after-effects of powders observed by this apparatus were compared with the printing effects of magnetic tape. These results made it possible to predict the printing effects of magnetic tape before the magnetic powders were actually used in the magnetic tape.
The Wiener spectrum analysis method is applied to the problem of extraction of the contribution of quantum mottle, structure mottle and film graininess to radiographic mottle. The normalized Wiener spectra of individual components were measured independently, and each contribution to the final output of radiographic mottle was obtained by a graphical comparison method. The dominant origin of the granularity was quantum mottle, and it ranges from 83 to 92 percent of the whole mottles if we evaluate the granularity of low spatial frequency. The main reason for the possiblity of separation of mottle components was found to be the wide differences of the spatial frequency ranges over which quantum mottle, structure mottle and film graininess spread. The results of measnrement of the fluctuation of X-ray quanta by two independed method, that is, the method of the Wiener spectrum analysis and the method of amplification factor, seem to agree quite satisfactory with each other.
General theoretical expressions are derived for the output probability distribution P (z) and the parameters m, s, α, β, …… corresponding to an input of normal random noise with an arbitrary power spectrum, when the input passes through a zero-memory, square law, nonlinear element and a linear filter of arbitrary impulse response. The theory is based upon the eigenvalue problem of a singular integral equation of Fredholm's type involving the autocorrelation function of input noise and a weighting function of linear filter. Detailed experiments sufficient to justify the above theoretical-consideration are given for the case in which the power spectrum of input normal noise is shaped by passing through the following three filters: (a) RC low-pass filter, (b) resonance circiut, (c) band-pass filter.
Temperature dependence of the photoelastic and Tetarded-photoelastic effect in polymers was inves-tigated with automatic recording apparatus using the method of Sénarmont's compensator. A reversal in sign of retarded-photoelastic effect is observed in two kinds of mixed polyesters, Hp, 3-1, when the temperature is increased from 15°C to 45°C. The temperatures at which the retarded-photoelastic effect vanishes, are about 40°C in Hp and 30°C in 3-1, respectively.