-
Shinjir\={o} Yasumi
1957 Volume 12 Issue 5 Pages
443-453
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The nuclear reactions of Al, Fe, Cu, Zn, Mo and Ag produced by the neutrons from the T
3(
d,
n) He
4 reaction have been investigated by means of the activation technique. The absolute numbers of activated nuclei in samples were determined by measuring the beta-rays from the samples with a 4π-proportional counter and applying the “method of extrapolation.”
By utilizing the variations of neutron energies in the laboratory system, an excitation curve of Mo
92(
n, 2
n)Mo
91 reaction was obtained. For the cases of Al, Cl, Zn and Ag, only the gradients of excitation curves were also found.
The experimental cross sections were determined as follows: 87.2 mb±8% for Al
27(
n,
p)Mg
27, 120 mb±12% for Al
27(
n, α)Na
24, 144 mb±13% for Fe
56(
n,
p)Mn
56, 556 mb±5% for Cu
63(
n, 2
n)Cu
62, 119 mb±12% for Zn
64(
n, 2
n)Zn
63, 60.2 mb±12% for Zn
66(
n,
p)Cu
66, 132 mb±16% for Mo
92(
n, 2
n)Mo
91, 458mb±11% for Ag
107(
n, 2
n)Ag
106, and 604 mb±11% for Ag
109(
n, 2
n)Ag
108. Comparing these results with the predictions by the statistical theory of Weisskopf
et al. it was found that they agreed with each other within about factor 3, but in details, there were some discrepancies between them.
The relative behavior of excitation curve of the Mo
92(
n, 2
n)Mo reaction seems to be consistent with the above theory, though with respect to the absolute values, the theoretical curve lies above the experimental one by about 2.4.
View full abstract
-
Senzo Tokunaga
1957 Volume 12 Issue 5 Pages
454-459
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Meson showers by heavy primary particles which have energy of 500 BeV per nucleon were studied with nuclear emulsions. Dealing with the event, “the nuclear disintegration cascade by heavy primary particle”, it was possible to estimate the energy of the primary particle with much accuracy by two methods, one by usual median angle of shower particles and the other by the opening angle of the fragmentation products of heavy primary particle. The angular distribution of the shower particle was studied and compared with the theory of Fermi and that of Landau.
View full abstract
-
Umejiro Yoshida, Akira Suzuki
1957 Volume 12 Issue 5 Pages
459-463
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
The surface potential of selenium was measured by Kelvin’s methods and was found to be influenced by the ambient. The characteristics of a rectifier obtained by making metal electrode contact with the selenium surface depend on the surface potential. The variation of the surface potential under illumination is of the same maginitude as the photoelectromotive force of the selenium cell. From these results, it is concluded that a blocking layer is formed on the selenium surface during the heat treatment.
View full abstract
-
Wataru Kinase, Hidetosi Takahasi
1957 Volume 12 Issue 5 Pages
464-476
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The energy of the 180°-type domain wall of BaTiO
3 crystal is obtained as 1.4 erg/cm
2 considering the dipole interaction and other interatomic energy of Born type.
The dipole interaction term has been obtained approximately from the difference of the energy of ferroelectric and antiferroelectric (stripes type) dipole configurations. The wall is found to be quite thin, that is, the change of polarization at the boundary is abrupt, in contrast with the ferromagnetic walls.
The structure of the 180° domains and their reversing process are also discussed.
View full abstract
-
Terutaro Nakamura
1957 Volume 12 Issue 5 Pages
477-482
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
After effect of the domain motion in rochelle salt crystal was observed for several hours. Quasi-static
f–
E hysteresis loop was obtained, where
f is the fraction of the domain saturated in one direction to the total volume of the crystal. Comparing this with
P–
E hysteresis loop at 50 cps, differences are remarkable. A.c. hysteresis loop has shallow sloping sides and high coercivity, while quasi-static
f–
E hysteresis loop is almost square and shows much lower coercivity.
f is time dependent and can be expressed in the formula:
f(
t)=1−
e−αtwhere time constant 1/α is about one hour for critical field about 60 v/cm, in the sample of thickness 0.6 mm at 10°C.
View full abstract
-
Sigemaro Nagakura
1957 Volume 12 Issue 5 Pages
482-494
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Thin nickel films formed by evaporation were carburized in CO gas stream at temperatures from 250°C to 500°C and were studied by electron diffraction. Only Ni
3C was found to be formed. This has c.p.h. arrangement of nickel atoms with lattice constants
ah=2.628 Å and
ch=4.306 Å, but showed super-lattice reflections due to a hexagonal lattice of
a=\sqrt3
ah and
c=3
ch, which is considered to be caused by a regular arrangement of carbon atoms.
The carbide was formed below 450°C in CO gas with slow rate and decomposed rapidly above 430°C in vacuum. The rate of the carbide formation was highest at about 350°C, although it depended very much on the texture of nickel films. Hydrogen atmosphere did not alter essentially the stability of the carbide.
It was found that nickel carbide is formed from metallic nickel with an epitaxial relation (00.1)
Ni3C⁄⁄(111)
Ni and [10.0]
Ni3C⁄⁄[10\bar1]
Ni (Ni
3C: c.p.h. indices) at the nucleation stage.
A mechanism of the lattice transformation from metallic nickel to the carbide was suggested. This mechanism explains the epitaxy and its destruction in the growth stage of the carbide crystal.
View full abstract
-
I. Errors due to the Approximation of Integration by Summation
Tadashi Ino
1957 Volume 12 Issue 5 Pages
495-499
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
In the calculation of a radial distribution function
rD(
r)=(1⁄2π
2)∫
0∞sI(
s)sin
sr dswe usually approximate the integral by such a sum as
rDΣ(
r)=(
Δs⁄2π
2) ∑\limits
n=1∞nΔs·
I(
nΔs)·sin (
nΔsr).
In this paper the mathematical property of
rDΣ(
r) is derived and the error due to the approximation is proved to be expressed as
rDΣ(
r)−
rD(
r)=∑
\substackm=−1
≠0\limits
∞′(
r+2
mπ⁄
Δs)
D(
r+2
mπ⁄
Δs).
Furthermore, the formula for the estimation of the error is derived. It turned out that in order to obtain a high accuracy from the approximation we must make the spacing
Δs less than π⁄
R0, where
R0 is the distance beyond which
rD(
r) is regarded practically zero.
View full abstract
-
II. Angular Momentum Distribution of OH* Radicals Splitting from H2O2 Molecules
Tadao Horie, Takayuki Nagura, Masamoto Otsuka
1957 Volume 12 Issue 5 Pages
500-505
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
A molecular spectroscopic study of the radiative collision of electrons with H
2O
2 molecules leads to a pronounced abnormal rotation of the OH
* radical split by electron impact from H
2O
2. A homogeneous electron beam is fired at right angles across a localized jet of H
2O
2 vapor in a vacuum chamber maintained at a pressure of about 1×10
−4 mmHg. The angular momentum distribution curve obtained shows a single maximum which is located near the rotational quantum number of 20, and the rotational temperature corresponds to 20,100°K, being remarkably higher than the initial gas temperature. In comparison with the double maxima found for H
2O, there are two differences, namely—the absence of the first maximum and the shift of the second maximum towards higher rotational quantum numbers.
View full abstract
-
Teruo Yukitoshi, Hirosi Suga, Syûzô Seki, Junkichi Itoh
1957 Volume 12 Issue 5 Pages
506-515
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
Proton magnetic resonance of solid hexamethyldisilane was studied. Line width and spin-lattice relaxation time were measured in temperature range from liquid air to room temperature. By analysing these quantities following results were obtained: Even at liquid air temperature, each CH
3 group reorientates about its three-fold symmetry axis so rapidly as to narrow the dipolar width due to three proton interactions within itself (activation energy 2.6 kcal/mole). Then at about −120°C, reorientation of CH
3-groups about the axis joining two silicon atoms becomes rapid enough to narrow the width further (activation energy 5.7 kcal/mole). Spin-lattice relaxation time varies qualitatively in accordance with the above considered reorientational motions. At −51.3°C, this crystal changes its structure and at the same time rapid reorientational motion of the molecular axis is excited, resulting discontinuous decrease in the line width and discontinuous increase in the spin-lattice relaxation time. Above the transition temperature, self-diffusion of molecule as a whole starts and the line width decreases gradually to zero (activation energy 10 kcal/mole). No change in the line width was observed at the melting point.
View full abstract
-
I. Strontium-Rich Ferrites and Cobaltites
Hiroshi Watanabe
1957 Volume 12 Issue 5 Pages
515-522
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Magnetic susceptibilities and electrical conductivities of (La, Sr)(Fe/Co)O
x samples sintered in vacuo or in oxygen stream are measured here. Samples containing tetravalent magnetic ions in general have Curie contants smaller than those containing only trivalent ions. This fact and the high conductivity in the former specimens strongly support the combined effect of the double exchange and the usual exchange mechanism in these compounds. The parallel alignment of spins of magnetic ions due to double exchange is partly or completely hindered by the presence of the strongly negative trivalent-trivalent interionic interactions.
View full abstract
-
Yoshika Masuda
1957 Volume 12 Issue 5 Pages
523-528
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The Knight shift, the line width and shape, and the spin-lattice relaxation time of the resonance line in metal cadmium are measured employing a nuclear magnetic resonance technique. The resonance line is asymmetric indicating an anisotropy of the Knight shift. From the analysis of these line shapes, the asymmetry in p-character of the conduction electron is estimated. The shift perpendicular to the c-axis is 0.42 percent and the shift parallel to the c-axis is 0.46 percent. The isotropic shift is 0.43 percent. In appendix, skin effect in metallic foil is discussed.
View full abstract
-
Yoshio Shibaoka
1957 Volume 12 Issue 5 Pages
529-532
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
The buckling of a uniform thin elliptic plate with clamped edge is dealt with in case when its periphery is subject to a uniform normal pressure in the plane of the plate, and the relationship between the critical buckling load and the eccentricity of the elliptic plate is shown graphically.
View full abstract
-
Yasujiro Kobashi
1957 Volume 12 Issue 5 Pages
533-543
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
With a view to observing pressure fluctuations in turbulent flow of fluid, a new apparatus was constructed by using a condenser microphone as a transducer with a ratio-discriminator. The frequency response of the apparatus was calibrated by means of Kármán vortices produced by a circular cylinder. The Helmholtz resonance and the loss in the pressure duct were compensated electrically by a band-rejection filter and a high-frequency booster. By these devices, the overall frequency response of the pressure-measuring apparatus was made flat between 50 and 1500 cycles per second. Using the apparatus in combination with a single rotary type hot-wire anemometer, it proved succesful in determining the intensity of static pressure fluctuation as well as the correlation between pressure and velocity fluctuation. Consequently all the terms in the energy equation became measurable, and the energy equation for the fluctuating quantities was ascertained experimentally for the first time in the wake of a circular cylinder, 1 cm in diameter, placed in an airstream of the speed 14 m/s, at a section 42 times the cylinder diameter downstream.
View full abstract
-
Fumio Tamaki
1957 Volume 12 Issue 5 Pages
544-549
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
Local flow fluctuations near the airfoil surface have been measured in the speed range near critical Mach number, by using a Mach-Zehnder interferometer and a rotating-drum camera. Airfoils tested are Tomotika-Tamada airfoil, NACA-0012 and 10 per cent thick elliptic cylinder. Experiments show that amplitude and frequency of oscillation that appears when the local sonic speed is exceeded on the surface depend on the shape of the profile. In the cases of T.T.- and 0012-airfoils, the oscillation is of small amplitude and high frequency when the maximum local Mach number on the surface is not much above unity, and the time-mean pressure distribution on the surface is smooth and shows no appreciable distortion due to shock waves. In the case of the elliptic cylinder, slow oscillation of large amplitude involving distinct shock waves appears, as soon as sonic speed is exceeded on the surface.
View full abstract
-
Fumio Tamaki, Chul-Soo Kim
1957 Volume 12 Issue 5 Pages
550-555
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
A shock tube having two partition diaphragms is devised for generating a hypersonic flow free from air-liquefaction. The tube consists of a high and a medium pressure chambers of equal cross-section and a low pressure chamber with a narrow, slit-shaped inlet and a large area divergence. Hypersonic flow is generated by the expansion into the low pressure chamber of the air, which is initially contained in the medium pressure chamber and compressed to high pressure and temperature by the nearly clossed-wall reflection of the shock wave created by the rupture of the diaphragm between high and medium pressure chambers.
Flow of Mach number 6.4 with a duration of 1 millisecond is obtained and used for the studies of the flow past elliptic-nosed plates. Axisratios tested are 8, 1 (semi-circular nose) and 0 (square nose). Pressure distribution over the surface and head drag coefficient are determined by using a Mach-Zehnder interferometer.
View full abstract
-
Y. Tanabe, S. Sugano
1957 Volume 12 Issue 5 Pages
556
Published: May 05, 1957
Released on J-STAGE: June 01, 2007
JOURNAL
RESTRICTED ACCESS
-
Masakazu Murakami, Toshiro Maeda
1957 Volume 12 Issue 5 Pages
557
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
-
Koichi Shimoda
1957 Volume 12 Issue 5 Pages
558
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS
-
Tadasi Numata
1957 Volume 12 Issue 5 Pages
559
Published: May 05, 1957
Released on J-STAGE: May 29, 2007
JOURNAL
RESTRICTED ACCESS