Vol. 4, No. 1 (1940)
1940-01-05
1940, 4 (1): 1-34.
doi: 10.7498/aps.4.1
Abstract +
The important part of the present paper deals with the deriva tion of,besides Reynolds' equation of mean motion,a set of equations of tarbclent fluetuation and its solution. The latter set follows necessarily,if we subtract the former from the original Navier-Stokes differential equations.To solve these equations of turbulence we build velocity and velocity, velocity and pressure correlations of the second and third orders and the differential equations satisfied by themIt is shown that these equations containing correlations have no defite solution unless two new hypotheses are introduced:one of them is merely a mathematical approximation in nature and the aacond can be interpretel physically that turbulence is the sum of two parta:one depends upon the mean pressure gradient in the moving fluid while the other does not. The general theory is then applied to explain the pressure flow between two paralel planes. The restlt is in good agreement with observation.
1940, 4 (1): 35-40.
doi: 10.7498/aps.4.35
Abstract +
The magnetic strueture of magnetite erystals was investigated by the powder pattern method. The patterns on the three prineipal planes were studied. It was found that the patterns formed on the tetragonal plane consist of irregular curves and that those on the digonal and trigonal planes consist of two and five sets of parallel lines respectively. By reversing the direction of the applied field the positions of the lines were changed. This indieates that the magnetite crystal has a magnetically periodical structure.With regard to the shape of the elementary domains, MeKechan and Elmore's bloek model is preferred to Müller and Steinberg's layer structure.
1940, 4 (1): 41-54.
doi: 10.7498/aps.4.41
Abstract +
The patterns of iron oxide deposited from a suspension have been studied on both the cold-drawn and annealed ferromagnetie substances. Three types of patterns on iron and two on nickel are found. They are all similar to, but less regular than,those found on monocrystal specimens. In the case of cobalt which is electrolytically deposited,the patterns consist of quite straight and nearly parallel lines having large spacing. After the specimen is quenched and then annealed, the patterns become highly irregular. A tentative explanation for each type of the patterns is given.
1940, 4 (1): 55-66.
doi: 10.7498/aps.4.55
Abstract +
The photographie effect of pressure was studied systematically. It is established that apart from the simple mechanical effect, which is caused by pressure alone,the mutual effect of pressure and exposure varies with the sequence of their application. X-rays were used throughout the investigation. If pressure is applied after exposure. the developability of the film is increased,the induction in density being proportional to the exposure. If pressure is applied before or during exposure, the developability may be either decreased or inereased,depending on the characteristics of the film used and the amount of the pressure applied. The effeet of pressure. when it is applied before exposure,is less pronounced than that in the ease of sinultancous application. The diference varies with t which is the time interval between pressure and exposure. If we plot the reduction in density D corresponding to a certain pressure and exposure against t, an equilateral hyperbola is obtained given by the equation （D-a)(t+β)=v. where a,β and y are constants.
1940, 4 (1): 67-76.
doi: 10.7498/aps.4.67
Abstract +
In order to explain the photographic effeets of pressure reported previously, a tentative theory of the latent image is presented. It is considered that the latent imnge consiste of deformed silver halide erystals of which the deformation must exceed a certain eritical value so as to render the crystals developable. The mechanism of ceformation due to the aetion of light is diseussed. The deformations in the erystal cansed by pressure when it is applied before or during exposure tend to aetivate the detaching of electrons from halide ions,a process which is essential in causing further deformation, However,the deformed regicns act at the same time as potential barriens so that the mobility of the detached eleetrons is loenlized. These two opposing tendeneies. the activation etfeet and the localization effeet,are in the opinion of the author responsible for the various phenomena observed.
1940, 4 (1): 77-88.
doi: 10.7498/aps.4.77
Abstract +
The branching ratio between actinium series and uraniumradium series has been redetermined direetly by means of a counter.The procedure consists in the extraction of protactinium by zirconium phosphate and by titanium oxide from a known uranium mineral,the determination of the efficiency of the counter by means of polonium,and the counting of a-partieles emitted by a known quantity of protactinium preparation. The number of a-particles counted is compared with that caleulated from the uranium contained in the same quantity of mineral. The ratio between them gives the branehing ratio between the two series. The mean value of the ratio obtained with both method of ex-traction is 3,969%,in kood agreement with the value 4% abtained by most predecessors using indirect ionization method. The results obtained by using titanium oxide closely confirms that obtained by using zireonium phosphate,which means that the former is as good an extractant of protactinium as the latter.
1940, 4 (1): 89-96.
doi: 10.7498/aps.4.89
Abstract +
The indicial impedance is defined as the voltage on a cireuit produced by a unit sndden rise of current passing through it. A theorem,called the eonjugate theorem, is proposed to establish the relations between the indicial impedances and the indicial admittances, Theoretical and experimental checks are presented.
1940, 4 (1): 97-115.
doi: 10.7498/aps.4.97
Abstract +
The conditions for producing distortionless complete plate modulation of triode radic frequency amplifiers are analyzed. It is shown that the only ay of meeting these conditions is to modulate the grid excitation voltage and the bias potential of the triode amplifier together with the plate supply potential. Calculations made on triodes of different amplification faetors and power ratings by the point-to-point method confirm the analysis. Comparison with modulation characteristies obtained by conventional method shows the distinet superiority of the present system.
