Diffusion of activators in nickel sleeve, commonly used as oxide coated cathode, is studied. Diffusion of particular activator is found to be affected by the kind and amount of other elements included in the sleeve. Diffusion coefficient of magnesium becomes smaller with the increase of manganese, silicon or iron content, whereas, that of manganese becomes greater with the increase of magnesium content. It is inferred that the change in diffusion coefficient D may be attributed not to the change in activation energy E but to the change in D0, these quantities being related one another by D=D0exp (-E/kT).
Characteristics of the unit for detecting displacement made of A. C. excited C-Shaped electric sheet steel (it may be called the moving coil type against the usual moving core type deferential transformer) have been discussed in the preceding reports. In view of practical application of the unit as an automatic control apparatus, further experiments are made. By devising phase separating circuits, the output is separated into advanced and delayed phase voltages, and the difference of integrals of the two voltages is indicated on a meter as positive or negative reading. Thus, by adjusting beforehand the position of the moving coil at zero of reading, steady detection of displacement is obtained with the accuracy of 0.001_??_0.002mm. Since a relay can easily be inserted in the circuit as it is and the circuit itself is sensitive, this device is considered beneficial to industry.
Receptors of vibration perception are examined and the effect of contact pressure on the detection of vibration tangible to tips of fingers is studied. Vibration perception is a combination of transient and stationary perceptions, the former is induced by nerve fibres in hair follicles, Meissner's corpuscles and Merkel's disks while the latter is by action current originated from stringing of muscles or equivalent physiological strain in joints. Stationary perception of vibration is experienced very often in everyday life and is measurable as it is of steady nature.
A measuring method is devised for the study of magnetostrictive vibration to make the theory of magnetization mechanism directly applicable. Both amplitude and phase angle of induced e. m. f. due to the vibration in a flat search coil are displayed simultaneously on the screen of C. R. O., the frequency-axis of which is driven by Foster-Seeley's discriminator. Thus, by a single sweep of this axis, the resonance behavior can be traced on a photograph. Analysis of the “resonance circle”, which is another representation of the result on a polar diagram, makes it easy to determine precisely the resonance frequency and affords us several interesting informations. It is found that the diameter of the circle, D, is proportional to the strain at any point of the specimen where the coil is placed, and also that there is a striking difference between dependencies of D on the intensity of magnetization in the two cases of longitudinal and torsional vibrations.
A large area photodiode has been made by evaporating thin gold film onto the clean surface of n-type germanium wafer and its photoelectric, temperature and spectral sensitivity characteristics are studied. Observed results are discussed by using an equivalent circuit deduced from theoretical consideration of the photo effect of metal-semiconductor contact barrier. It is ascertained that the series resistance of photodiode-one of the most important factor for the short-circuit photo-current-is mainly caused by evaporated gold thin film. Experimentally the value of about 1212 series resistance was obtained for the largest short-circuit photocurrent. The sensitivity of short-circuit current was a few milliamperes per lumen. The spectral sensitivity was not decreased for shorter wave lengths as expected from intrinsic photoconductivity of germanium. This may be explained by considering the spectral transmittance of the thin gold film on germanium. Open-circuit voltage and short-circuit current decreased and photo saturation current increased with the rise of temperature. These results are explained by computing the sign of derivative with regard to temperature for each quantity deduced from the equivalent circuit theory.
Gated-beam tube, 6 BN 6, has been used in frequency discriminators, phase-sensitive detectors and in coincidence circuits. In this paper, some novel devices of electronic circuits using the gated-beam tube are described. A frequency discriminator for low frequencies, pulse generators, frequency dividers and saw-tooth wave generators are shown with complete circuit diagrams. The frequency of relaxation oscillation is given approximately by a simple formula, and the pulse-width is shown graphically. A pulse generator can be constructed with only two 6 BN 6 tubes, the repetition frequency of which is adjustable by a variable resistor from 20 to 9000 c. p. s. and the pulse-width is adjustable by a variable capacitor from 0.5 to 10 micro-seconds, the rise time being 0.04 micro-seconds. The repetition frequency can easily be reduced to lower than 10-2 c. p. s., while the maximum is near 1 Mc/sec. As to the frequency divider, frequency dividing from either 500 to 1 c. p. s. or 1 Mc/sec to 2 kc/sec is practicable using only four 6 BN 6 tubes. Its operation is considerably stable and reliable.
The true dew point should be the temperature at which the thermal equilibrium is established so that the amount of dew on the mirror of dew point indicator neither increases nor decreases, remaining constant. In conventional dew point indicator, however, contamination on the mirror causes water vapor being adsorbed on the surface and low pressure dew is formed before the true dew point is reached rendering the determination essentially uncertain. A means was devised with which the thermal equilibrium is automatically maintained. By letting first a small amount of dew form on the mirror, subsequent change in the amount of dew form on the mirror, subsequent change in the amount of dew becomes solely depending on the humidity of the surrounding air, the thermal equilibrium being unaffected by the forming of low pressure dew. Two photo-tubes connected in series receive light from a source, one directly through an adjustable slit and the other by reflection from the indicator mirror. Weakening of the latter intensity due to forming of dew on the mirror is countervailed by narrowing the slit. By means of an electronic circuit and by using proper width of the slit, resultant photo-current automatically controls the mirror temperature to balance the two photo-currents thus quickly establishing and correctly maintaining thermal equilibrium.
There are cases in which the dew point appears higher than it should be or temporarily lower according to the kind of contamination on the mirror of indicator. This effect can be eliminated by narrowing the slit to dim the light that falls on the reference photo-tube slightly weaker than the light reflected from the indicator mirror, thus allowing the contamination to take its effect at first. To minimize depression of the dew point due to over-cooling of the mirror body or to setting of the slit being too narrow, the mirror body which is a hollow cylinder in this work had to have a large interior volume. With due attention paid, the dew point is obtained within the error of ±0.1 degree.
Optical measuring apparatus for top edge angle and top edge radius of flade has been devised. A modulated light reflected on the top edge of flade is caught by a photocell and the current produced is amplified. Finishing repeated 10 times made the top edge angle wider but the top edge radius remained unchanged. Paper cutting tests repeated 50 times made the top edge angle wider and the top edge radius greater. Top edge radius is the decisive factor for string cutting. Paper cutting is influenced by both the top edge radius and the top edge angle.
Thermal conductivity of several kinds of igneous rocks containing Granite, Diorite, Gabbro, Liparite, Andesite and Basalt, 45 in all, are measured by the divided-bar method at various temperatures from 140°C upto 280°C. Measured values vary for different kinds of rocks ranging 3_??_6×10-3cal/cm. sec. and for rocks of the same kind, the conductivity seems proportional to their bulk density. Temperature coefficient of thermal conductivity is positive except for Granite and Liparite.
For the purpose of assuring the waterproofness of materials used for electrical appliances, some experiments have already been carried out by the author on wettability of solids to interpret it from practical and theoretical view-points. In this paper, observations are first made on the change in configuration of water droplet evaporating on organic polymer solids and on the relation of time required for complete evaporation to the contact angle between the droplet and the solid. Difference in wettability of polymers is then studied and discussed. Next, discussion is also given on measured changes in wettability of polymers in contact with water. In general, there are two factors to be considered which are likely to influence the wettability of solid surface in contact with water, namely the penetration of water molecules into the solid and the change in orientation of polar groups in the solid. Because of permeable nature of water molecules, the penetration theory is adopted, and by assuming the wettability to be proportional to the amount of sorbed water, the following equations are derived for the time rate of wettability: (W-W0)/(Ws-W0)=4/_??_·_??_ W=σι cosθ where D is the diffusion coefficient of water molecule, d the thickness of the solid, t the time, σι the surface tension of water, θ the contact angle, and W0 and Ws are the amounts of wettability W at t=0 and t=∞ respectively. To a certain extent, these equations gave a clue for discussing the observed data and reasonable values of diffusion coefficient were obtained.