For measuring viscoelastic properties of materials, especially of high polymeric substances, by the use of the composite oscillator method, ADP crystal has many advantages over quartz which has been widely used. This is chiefly because of the lower density and lower elastic modulus of the former. Dynamic Young's modulus and associated loss factor are determined for phenol resin, polystyrene and polyethylene by the composite oscillator method using ADP 45° Z-cut longitudinal oscillators. On modulus-temperature diagram of polystyrene characteristic break points are observed at 57 and 80°C which coincide with those found in volume-temperature relation. The loss factor of polyethylene has a maximum (socalled “β-peak”) at 4°C (42 kc/s).
Electro-optic coefficient γ63 of ADP crystal is measured up to the microwave field of 3000 Mc frequency. The result shows that the value of γ63 remains unchanged agreeing with that in clamped condition obtained by R. O'B. Carpenter, T. Tsutsui and S. Namba within experimental errors. Method of measurement and consideration on experimental errors are described.
A study on voltage efficiency of bored electrodes for ADP electro-optical elements has been made by means of the electrolytic cell method. At first, center voltage efficiency is measured and the effects of the width of the electrode, the diameter of the hole, the gap of the electrodes and so on are investigated. Next the relation between these values and the mean voltage efficiency are studied. The electrodes which are studied are 4 kinds of single hole electrodes (ring, square, hexagonal and slit) and 3 kinds of net electrodes (lattice net, hexagonal net and fluted net). The following result is found for all kinds of electrodes. The center voltage efficiency ec is expressed, if the variables are within some limitted range, logec=-αd/t+Alogb/d+B0+Clogn where α, A, B0 and C are constants which depend only on the type of electrodes. The mean voltage efficiency e is expressed e=mec-m+1 where m is the constant which also depends only on the type of electrodes.
The electro-optic effect of KDP crystal is larger than that of ADP crystal, it can be used for devising a high speed light shutter. Some experimental data for the design of a KDP shutter affording the exposure of 10-6_??_10-7sec are given. (1) The measured value of electro-optic constant γ63 is 10×10-7 cm/kV at the wavelength of 546mμ. (2) Conditions for the growth of KDP crystal plate are studied. (3) Several transparent electrodes are examined. NESA glass electrode with evaporated gold grid, metal ring electrode and evaporated gold grid electrode are available for applying pulse voltage to the crystal. (4) Breakdown voltage of the crystal for different thicknesses is measured by using high voltage pulses. (5) Main pulser for the shutter is designed. (6) Pattern indicating the pinch effect of discharge column is shown on photograph taken by using the shutter.
Recently, for photographing high speed phenomena, exposure time of 1 μs or less has become a matter of great concern. Hitherto, there are three ways of answering the purpose, namely, (1) the electron-optical shutter using image converter, (2) the rotating mirror and (3) the Kerr-effect shutter using nitrobenzene, but none of them is very practical. The author has been experimenting with the Kerr-effect shutter using ADP (ammonium dihydrogen phosphate) and completed a trial model of high speed camera with the performance: (1) a pulse generator supplies the ADP shutter with pulses of 0.5 or 1.0 μs in width and 8.0 kV in height, (2) the interval between input signal and 1st pulse is controlled from 1 to 20 μs and that between 1st and 3rd pulses is also from 1 to 20 μs and (3) three successive exposures are possible. 4/6μF, 30 kV spark and simultaneous explosion of fuse metal were photographed with sufficiently definable S/N-ratio and resolving power.
In the author's preliminary report4) in 1954, description was given of accurate determination of ultrasonic velocity in liquid by establishing in it ultrasonic grating through which a narrow beam of light is diffracted. It was shown that the wavelength can be determined by widening the slit for the beam of light until one order of diffracted image of the slit connects with the next by broadening. The device has since been improved to be put to practical use for ascertaining the purity of liquid chemicals. A single lens magnifier, which is made interchangeable with a 50_??_100 power microscope, is provided. For the ease of observing the contacting of two successive images of the slit, a minute sharp appendage is attached to one of the jaws of the slit, and to better the ultrasonic transmission, the bottom of cuvette is made of a resonant quartz crystal plate acting as acoustic window by means of which only 100 volts for oscillator and 100_??_150 volts for amplifier tube of ultrasonic generator sufficed to obtain many bright images. In operation, the width of the slit at which two successive images are just in contact is read on a vernier scale. Accuracy of 1m/sec. in wavelength measurement is attained.
Observation is made on the following remarkable properties of rectangular glass rod revealed by instantaneous photographs of fracturing when shot tranversely by bullets with impact velocities of 230 and 400 m/sec. (1) There are two kinds of fracturing: one is the fracture progressing from the point of impact in zigzag course which is considered due to transverse stress wave (named zigzag fracture), and the other is the fracture developing in reverse direction from the free end to the point of impact by longitudinal stress wave. (2) The zigzag fracture is due to the repetition of restitution force taking place as thefracture progresses. (3) Propagation velocity of zigzag fracture is approximately 2600 m/sec. and that of fracture itself is approximately 2850 m/sec. (4) Unaffected region is observed close to the free end resulting from the interference of incident and reflected pulse waves at the boundary surface. (5) Fracturing is little affected by the change of impact velocity.
For measuring the true density of porous, granular, powdery or water soluble solid material, a portable volumeter has been devised. A metallic bellows, which contains a piece of sample and issealed with a plate lid, is compressed from outside by rotating a micrometer screw head. From the pressure change measured by a metallic diaphragm sensitive manometer and the volume change read by the screw head advance, the unoccupied volume can be determined. Cares to be taken when operating the instrument are discussed and examples of measurement are shown.
Quantitative relations of ultrasonic absorption and relaxation frequency to temperature have been obtained for binary liquid systems which have the critical solution temperature. The cases have been discovered for trinary liquid systems prepared adequately that absorption equal to that of critical solution exists in spite of having no critical solution temperature and that for binary liquid systems the critical solution temperature differs more than twenty degrees from one calculated from the presented formula. The formula has also been tried to solutions of moderate concentration having no critical solution temperature but a maximum absorption.
An application of the theory of stochastic processes to the static fracture of non-homogeneous brittle materials such as portland cement concrete is presented. A large number of flexural failure tests on standard mortar specimens specified in JIS have been carried out under constant loads as well as under uniformly increasing loads, and the results are analyzed statistically from the standpoint of stochastic theory. It is concluded that the scatter observed in the delayed time for fracture or the static fracture strength of concrete appears to be an inherent characteristic of the material itself associated with a Markoff process as a kind of rate process.
Infrared image converter tube which renders infrared images visible is successfully utilized as an optical pyrometer of disappearing filament type. Temperatures in the range of 350_??_V700°C which are too low for the customary optical pyrometer can be measured. Measurable accuracy, rational consideration on measurable range of temperature and data for design of the pyrometer are given.