Transmissivity of 35 kcps ultrasonic waves through various kinds of paper, texture and plastic films is measured by the use of ADP transmitter and receiver. Transmissivity has a close correlation with mass per unit area for plastic films and nonporous paper. Porous paper and texture show a better transmission. The possibility of determining permeability of paper and texture or water content of paper from ultrasonic wave transmission is proposed. A simple apparatus for measuring sound velocity in a solid by ADP transducers is described with some examples of observed data. Change in velocity is measured in the process of setting of plaster of Paris. Flaw detection in a veneer plate is also carried out by the above apparatus.
As reported in the previous paper (J. Appl. Phys. Japan 27 (1958) 652), ADP longitudinal oscillator has many advantages over quartz when used for measuring complex Young's modulus of high polymers by the composite oscillator method. In the present paper experimental techniques of determining complex rigidity of high polymers by the use of a torsional ADP oscillator are described with some results for polystyrene and polymethyl-methacrylate. In this case, contrary to the case of a longitudinal oscillator, ADP crystal seems to be not always preferable to quartz because of the complicated construction and difficulty in mounting of the oscillator.
Physical properties and some applications of piezo-optic resonator are given in the author's previous papers. The validity of the author's equation Γz=_??_Qno3d36P66Vz for large amplitude of oscillation at resonance is verified by comparing the interference figure obtained under such conditions with that not at resonance by 50 cps high voltage source. A device is made for the direct reading frequency analyser previously reported to be of double tuned characteristic by placing two resonators of equal thickness, slightly different in resonance frequency, side by side, between converging and projector lenses of a conoscope. Since the conoscope figures are by the interference of equal inclination, two figures by those two resonators of equal thickness appearing on the focal plane of the projector lens are of the same size which gives the conoscope the double tuned characteristic. The Q values of ADP crystal resonators are not affected by relative humidity of under 50%, but above it, the values decrease remarkably.
A graphical method for solving second or third order ordinary differential equations mainly representing nonlinear oscillations is studied. The method described is an extention of phase-plane-delta method reported by L. S. Jacobsen. He formulated the ordinary differential equations as x+p2x=p2δ(x, x, t) and solved it on the usual (x, x/p)-plane. The phase trajectory is constructed as a series of circular arcs centered at δ on the x-axis. In the δ-L method used here, the differential equations are formulated as x+ƒ(x)x+x=δ(x, τ) or α(τ)+g(x). Introducing a new variable V=x+F(x) or V=x+F(x)+A(τ) where F(x)=∫ƒ(x)dx and A(τ)=-∫α(τ)dτ, a new (x, V)-plane is assumed which may by considered as an extention of the Liénard plane. Then the trajectory on the (x, V)-plane can also be constructed as as eries of circular arcs, the centers of which are located at the point (δ, F) or (g, F+A) on the whole plane. By this improvement, the centers of arcs are calculated more easily and the physical meaning of the solution becomes more apparent. Three examples are given for illustration. One of them is a differential equation of the third order for the case of a grid tuned oscillator having auto-bias voltage. Equations of this kind can be solved in the same way as the second order equations after δ-terms are calculated by simple numerical integrations. In this example, the solution is also represented in special (x, V, δ=W)-space. By this representation, the solution can be immediately understood in contrast with that in the usual (x, x, x) -space.
A simple method for measuring the temperature dependence of linear expansion coefficient and specific resistance of iron wire at high temperatures is shown. The iron wire on the middle point of which a small weight is set is stretched horizontally between two fixed points and is heated directly by d. c. supply. The amount of the sag due to the elongation of the wire as well as the potential drop between the two ends caused by the heating current are observed with which the linear expansion coefficient α and the specific resistance ρ of the iron are obtained. The experimental results show that a remains constant in the temperature ranges from 1000°C to A3-point and from A3-point to 700°C, and has a discontinuity at A3-point. It is also found that the temperature dependence of ρ varies anomalously at A2-transition point. Any anomalous variation was not observed at A3-transition point.
There are two methods by which the particle size is determined by higher-order Tyndall spectra: (1) by measuring the red angle and corresponding red number nR, (2) by measuring the first red angle. The latter is based on the linear relation existing between logarithm of the firstt red angle γ1 and logarithm of the radius r of the particle. By using stearic acid and DOP ass samples, radii (0.3_??_0.7 μ) of aerosol particles are measured by high-order Tyndall spectra. Aerosol is made by La Mer's aerosol generator and scattered light is used without being resolved into plane-polarized components. The following are concluded: (1) nR+1 and nR approximate to the radius of aerosol of stearic acid and of DOP respectively. (2) In the case of stearic acid, experimental curve and theoretical curve for n=1.44 both representing the relation log γ1vs log r coincide well, but not so in the case of DOP. (3) The scattered light is reddish in the range of angles where J(628)/J(523) is larger than 1.0 as previously reported by the author.
Wave motion of liquid in a vessel which oscillates vertically with periodic up-and-down motion is studied. As the motion of the vessel has no horizontal component, any kind of wave motion of liquid may not seem to occur. But this is not always true. According to the results of the analysis described here, the wave motion of liquid with up-and-down motion actually occurs and becomes divergent under certain conditions expressed by Mathieu Diagram. The analysis is accomplished under three assumptions that the liquid has no vortex, the liquid is uncompressible and spatial wave length is large enough compared to the depth of the liquid. This analysis covers over one and two dimensional wave motion. Experiments are performed also in one and two dimensions and agree with this analysis.
This is the second part of the study on plastic bending of copper sheet concerning the damage suffered by the sheet during the bending process by punch and die. The mechanism of the origination and growth of the damage is investigated. The damage is originated by the vertex of punch as a notch and by the sharp corner of die as a scratch. Result of the experiment is considered statistically and analytically. Generalized conclusion is as follows: (1) The plastic deformation occurs within a small region around the punch vertex. (2) Development of spring-back is negligible at any stage during the plastic deformation process; it is at the final stage of stroke that the spring-back is strongly effected. (3) The scratch is developed by sliding of die corner over the sheet; its length increases parabolically with the advance of stroke. (4) The notch is developed by the indentation of punch vertex; its width increases linearly with the advance of stroke. Based on the above, the fundamental of the design of punch and die is studied.
Light figures revealed by Ge single crystal surface etched with various chemical reagents are examined if they are applicable to the determination of crystal orientation. The figures are analyzed and the structures of the etched surface are observed under microscope, from which information regarding the revealed crystal face is obtained. Distinct light figures suitable for the orientation work are obtained by a short-time etching with concentrated nitric acid plus water plus hydrofluoric acid plus silver nitrate (45 cc+45 cc+10 cc+50 or 20mg or 20 cc+40 cc+40 cc+2g), with hydrofluoric acid plus hydroperoxide plus water (1 : 1 : 4), and with hydroperoxide (100°C). Among these etchants, hydrofluoric acid plus hydroperoxide plus water (1 : 1 : 4) is most suited for accurate orientation determination. Generally, the crystal faces developed by etching are found to be those belonging to the principal crystal zones, but dilute nitric acid heated at 70C° gives some additional high indexed crystal faces belonging to a high indexed crystal zone. There is a tendency that low-index crystal faces appear by a short time etching and high-index ones by a prolonged etching. It is to be added that relatively chear light figures are obtained on germanium crystals, as polished with SiC powder.