A new electron lens system of electron microscope excited with permanent magnets has been designed. It has variable magnification of over a wide range, a resolution of 30 A, and is possible to obtain diffraction patterns. The construction of magnetic circuits, characteristics of double gap lens and three stage lens system, variable method of focal length are described and micrographs taken by the instrument are shown.
It is well known that if one places a pendulum with an iron bob in the neighborhood of a coil fed from the main, one observes that the pendulum attains its stationary oscillation. It seems that there is no necessity of a rational ratio between the frequency of the pendulum which is close to its proper one and the frequency of the main which is very high compared with that of the pendulum. In this paper, this phenomenon, first treated by J. Bêthenod, is studied analytically and it is concluded that the dissipated energy of the pendulum is supplied from the main by some retarded action of the electromagnetic force of the coil. The method of analysis can be applied to a class of electromechanical phenomena in which the mechanical system is maintained in oscillation at a frequency of or near its proper one at the expense of the energy supplied from the electrical system. Further, an electromechanical rotator based on the same principle as the Bêthenod's pendulum was devised and the experiment of which seems to support the validity of the analysis. Finally, the case in which the electrical system is a series ferroresonant circuit is discussed and it is pointed out that the energy of the pendulum is supplied by the oscillation hysteresis of the nonlinear circuit. As an application of this phenomenon, an electric master clock without electric contact was devised.
When electrolysis occurs in the glass stem of a vacuum tube during its operation, the potential distribution in the glass is always linear, but the gradient of the potential decreases due to the increase of the interface resistance on the positive electrode which is sealed in glass for metal welds. The oxidation is supposed to proceed on it, because the colour of the interface seems to change from that of lower oxide to that of higher oxide of metal.
It is shown by electron diffraction that the substance of interface layer between metal electrode and glass caused by electrolysis of the stem undergoes transformation. For example, the substance of interface formed into TiO in the stem making is reduced at the negative electrode by the natrium ions moved to negative side and is oxidized into TiO2 at positive side by the excess oxygen ions left around the positive electrode. The electrical resistivity of the oxidized layer increases exponentially at the first stage of electrolysis and linearly with time at its final stage.
D.C. stability of self-biased flip-flop circuit has been studied. The self-biasing is preferable for the benefit of good stability against the changes of power voltage. There are some commendable D.C. designs for fixed biasing but optimum bias design has not been worked out. This report gives the optimum bias value (Eq. 10) with the optimum dividing ratio of grid resistance (Eqs. 14_??_17), enabling to secure the best working condition for every type of tubes. An example of the design, a stability test and the result of over one year's continuous operation are also given. Permissible minimum plate load is discussed considering the stability conditions and maximum plate dissipation of several types of tubes. This design system has proved to be very useful.
Characteristics of vibration tangible to the tips of fingers have been observed in some conditions of contact with a vertical vibration generator. It is found that the amplitude of same tangible vibration _??_ is represented approximately by _??_ _??_ the amplitude of same tangible vibration in μ K a parameter in μ ƒ the frequency per sec h2 a damping constant n1 the 1st order natural frequency of the vibration n2 the 2nd order natural frequency of the vibration θ the phase angle meaning the degree of contact conditions above equation has been developed from the equation given in the previous report (J. of App. Phy. Japan, Vol. 24, No. 3, p. 118). It is concluded that the human body can be represented by a fine vibrograph, its characteristic impedance being equal to the product of the sum of impedances of displacement and velocity vibrographs and the impedance of accelerometer, involving the phase angle which represents the contact conditions.
Relations of transistor noise power with surrounding temperature are measured at 1000 cycles. The result is interesting in that a pronounced difference is observed between the noise characteristics in room temperature region and those in a lower temperature region. Reasonable explanations are given of the difference by studying separately the surface noise, the leakage noise and the diffusion noise as defined by W. H. Fonger. So experimental' verifications are made.