The temperature dependence of breakdown field, distribution of time lag, and dielectric constant in high electric field were studied on polycrystalline BaTiO₃. The d. c. breakdown field is nearly constant in the temperature range 20 to 150°C, on the other band the pulse breakdown field changes markedly near the Curie temperature (120°C). The time lag is statistical and depends on the applied field. The “total” dielectric constant in high fields behaves differently from that in low fields, that is higher in ferroelectric state than in paraelectric state, decreasing remarkably near the Curie temperature. From these facts, it is concluded that the breakdown is of the avalanche type. It is suggested that the pulse breakdown field ralates to the high field dielectric constant and the d. c. breakdown field is affected by the transport of free charge.

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Absorption spectra of KCl:In and KCl:Sn are studied at various temperatures, and all the A, B, C and D bands corresponding to those well known in KCl:Tl are found. In KCl:In, the intensities of the A, B and C bands are proved to be proportional to the concentration of In⁺ ions. The ratio of the dipole strength of the C band to that of the A band is found 54 in KCl:In and 18 in KCl:Sn. The position of the B band is 267 mμ (4.64 eV) in KCl:In and 251 mμ (4.9 eV) in KCl:Sn. The relation between the dipole strength and the position of the B band seems to support the theory given by Sugano. Further, it is found that both the A and D bands have a multiplet structure, the A band a doublet and the C band a triplet, both in KCl:In and KCl:Sn. Their origin is discussed.

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The photographic study of X-ray diffuse scattering from a single crystal was made in order to determine the rotational disorder of NO₃ groups above the critical temperature 275°C. The rounded diffuse maxima which appear at the positions of super-lattice reflections of the ordered lattice are identified with those due to the disorder of NO₃ groups. It is concluded that the rotation of NO₃ group is hindered and the NO₃ group is almost bound in two positions which have the calcite-type of coordination with the surrounding Na atoms. There exists such a short-range order that the neighboring NO₃ groups have a tendency to take the ordered arrangement.

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A treatment of the non-ohmic and anisotropic effects of galvanomagnetic coefficients for warm electrons in many-valley semiconductors is presented. Kohler’s variational method can be applied to solving the Boltzmann equation for warm electrons in many-valley semiconductors, with scattering by acoustical and optical lattice vibrations, and thus obtaining expressions for the galvanomagnetic coefficients in any crystallographic directions.
All of the galvanomagnetic coefficients for warm electrons in n-Ge can be obtained in the form of the quadratic dependence on the electric field strength for the whole region of magnetic fields. It is thus found that everything so obtained has anisotropy effects and decreases with increasing the electric field strength except for the electrical conductivity at very strong magnetic fields.
In the very strong magnetic regime the electrical conductivity, for the case of acoustical lattice scattering only, has the electric field dependence opposite to that in zero magnctic field and thereby increases with increasing the electric field strength.

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The microscopic studies of N₂ on Mo have been made and compared with the results of the macroscopic studies. The non-dissociative chemisorption ε occurs on the crystal planes of average five nearest neighbours, and the ε-adatoms increase the work function of these planes as much as 0.5 eV. While, the dissociative chemisorption ζ occurs on the planes of four nearest neighbours, and the ζ-adatoms lower the work function slightly, 0∼0.₅ eV. On the planes on which the ε and ζ-adsorptions take place contiguously, the values of the work function changes lie between 0 eV and +0.5 eV.
The results for Mo are similar to those for W.

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The nuclear magnetic resonance of iron group element alloyed with Palladium has been studied with special emphasis on dilute ferromagnetism and the giant moment problem. This paper reports on the NMR of Co⁵⁹ in dilute ferromagnetic Co-Pd alloys and gives a simple interpretation of these results. The resonance frequency of Co⁵⁹ in these alloys was about 216 Mc at liquid helium temperature, nearly the same as that in pure fcc cobalt, 217.2 Mc at 0°CK. This suggests that the magnetic moment on Co atom is roughly equal to that in pure cobalt metal. By use of these results the range of the magnetic interaction of Co atoms in these alloys is roughly estimated using simple probability arguments. The giant moment is constructed from the sum of the moment of the Co atom and the moments of Pd atoms within an interaction “distance” from the Co atom.

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The de Haas-van Alphen Effect in antimony single crystals was studied by means of a torque method at liquid helium temperature in magnetic fields up to 23 kilogauss, which were applied parallel to the trigonal-bisectrix, the trigonal-binary and the binary-bisectrix planes. New carrier oscillation periods were observed in addition to the periods corresponding to the tilted ellipsoidal Fermi surfaces proposed by Shoenberg, and the corresponding mass parameters were evaluated. These new carrier oscillation periods agree with two possible models of the Fermi surface for the hole. They are discussed with reference to the number of carriers.

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The changes of resistivity during isothermal aging after quenching were measured in Al–10wt%Zn–0.10wt%Si, Al–10wt%Zn–0.12wt%Ge and Al–10wt%Zn–0.01wt%Sn ternary alloys and the interactions between a vacancy and an Si, Ge or Sn atom were studied. General features of clustering in these alloys were not different from those in Al–10wt%Zn binary alloy. Therefore, the binding energy could be obtained by taking ratio of time, t_Mt, to reach the maximum of resistivity in ternary alloys with that time, t_Mb, in binary alloy. Binding energies between a vacancy and an Si, Ge or Sn atom were deduced to be about B₁+0.10, B₁+0.15 and B₁+0.25 eV, respectively, where B₁ is binding energy between a vacancy and a Zn atom.

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The change of resistivity during isothermal aging after quenching were measured in Al–10wt%Zn–0.13wt% Mg and Al–10wt%Zn–0.3wt%Mg alloys. General features of clustering in these alloys were different from those in binary Al–10wt%Zn alloy. Small increase of resistivity occured before main increase of resistivity due to clustering of Zn atoms. This small increase of resistivity was attributed to clustering of both Mg and Zn atoms into G. P. zones which were diffrent from those in binary Al–Zn alloys. Time required to reach maximum of resistivity in these alloys was much longer than those in binary alloys. it was deduced that this fact did not depend upon large binding energy between an Mg atom and a vacancy but might be due to interaction between G. P. zones containing both Mg and Zn atoms and vacancies.

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The energy band structure of ferromagnetic nickel is evaluated by the Green’s function method and the interpolation method developed by Slater and Koster. The effective potential is suitably chosen so as to give a reasonable fit with the results of recent experiments about the Fermi surface.

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In order to clarify the origin of ferrimagnetism of Cr₅S₆ and Cr₂S₃, the effects of quenching from high temperature and of pressure squeezing at various high pressures upon their magnetic properties were observed. X-ray diffraction patterns of these two compounds were also observed before and after quenching or pressure squeezing. From these experiments, it becomes evident that the ferrimagnetism in Cr₅S₆ and Cr₂S₃ is originated from the ordered arrangement of vacant sites of cation. Moreover, the Curie temperatures of order-disorder transition of vacancies in Cr₅S₆ and Cr₂S₃ were found to be about 340°C and 560°C, respectively.

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Effect of Coulomb Correlation on the line profile of the X-ray which is scattered inelastically by an electron in the degenerate electron gas has been calculated. The calculation is performed by marking use partly of dielectric formulation in random phase approximation and partly of canonical transformation method. The effect is quite small for large angle scattering, but for small angle scattering it becomes essential. Particularly for the angle where the momentum transferred to the photon is smaller than the plasma cut off momentum, the scattering is interpreted as the excitation of plasma oscillation. The discrepancy between the experimental value of the line width and the calculated value by Donovan and March cannot be explained by Coulomb correlation. A brief indication for the future experiments is given.

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Conformation of the syndiotactic vinyl polymer in dilute solution is treated, and the mean square dipole moment and the mean square end-to distance of the polymer are calculated. The polymer is regarded as a flexible chain made of segments, and the potential of internal rotation of the polymer molecule is approximated by a square well potential. Results of the calculation are compared with the case of the isotactic vinyl polymer, and it is concluded that the excluded volume effect is negligible in the syndiotactic vinyl polymer, although that effect is large in the isotactic vinyl polymer. In order to eliminate some unsuitable types of internal rotation, a physical consideration is used together with a method of numerical calculations.

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The negative absorption at the electron cyclotron frequency in weakly ionized gases is examined under the following conditions: The plasma is so tenuous that its refractive index is close to unity and plasma electrons have a spherically symmetric distribution function in velocity space. Also the effective collision frequency for momentum transfer is dominantly due to the collision of electron with neutral particles and varies with speed v as ν(v)∝v^h. The condition of negative absorption is given by h>3 for the electrons’ distribution function f(v)∝δ(v−v₀) and q+3>h>3 for f(v)∝v^qexp(−bv^l). The absorption coefficient, the radiation temperature and the radiation intensity corresponding to the negative absorption are derived and their characteristics are discussed in detail.

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The effect of suction on heat transfer with internal heat generation or absorption in a viscous flow at a stagnation point is analysed. For large values of the suction parameter κ, a series solution of the energy equation is obtained in inverse powers of κ, while as for small values of κ, the energy equation is solved numerically. Results are obtained for both strong and weak sources or sinks for Prandtl number equal to unity and the effect of suction on the heat transfer is brought out.

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The problem of heat transfer due to the flow of an electrically conducting, viscous incompressible fluid between two infinite parallel plates, one rotating and the other at rest, under the effect of a magnetic field acting perpendicular to the plates, has been considered. The distance between the plates has been assumed to be small, thus making the Reynolds number ‘R’ small. The flow parameters as well as the temperature have been expanded in powers of R. The temperature versus distance graph reveals that the maximum temperature occurring between the plates increases, the plane of maximum temperature shifts towards the rotating plate and the rate of heat transfer from the rotating plate increases with the increase of Hartmann number. When the edge effects are neglected, the quantity of heat transfer per unit time from a finite disk of radius a has been calculated. It is found that the magnetic field has a very slight effect on the rate of heat transfer from the stationary disk.

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Temperature variation of ultrasonic velocity in aqueous solutions of chlorides of magnesium, strontium, and barium, bromides of strontium and barium and oxalates of lithium and potassium has been studied using the fixed-path interferometer technique. Variation of adiabatic compressibility, molar sound velocity, apparant molal compressibility and hydration number, with temperature has also been studied and the results are discussed in the light of the Marks’ finding in a similar study of the electrolytes.

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The impulsive motion of a sphere along a plane wall in a viscous fluid is treated on the basis of the Stokes approximation. A solution to the equations for unsteady motion is obtained by applying the Laplace transformation with respect to time to the basic equations. Results obtained to a first approximation for the drag and the torque acting on the sphere show that:
1. A sphere which starts impulsively to translate parallel to a wall experiences a drag and a torque about its center.
2. When a sphere begins impulsively to rotate near a wall, it experiences a drag as well as a torque.
3. The additional contribution to drag or torque due to unsteadiness of motion decreases with time as t^−3⁄2 (t is the time) in the presence of a wall.

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The unsteady flows of a perfect fluid caused by the motion of two circular cylinders and of two spheres which pass by each other are investigated by image method, in order to estimate the pressure variation when the two high-speed trains pass by each other. It is shown that (i) the three-dimensional passing-by phenomena are qualitatively much the same as the two-dimensional passing-by phenomena, but are quantitatively far less important, and that (ii) the calculated results (three-dimensional) agree with the actual data from the passing-by test of trains not only qualitatively but also quantitatively.

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The present paper concerns the study on the distortion of a uniform magnetic field, which is parallel to the flow at infinity, caused by the flow of an incompressible inviscid fluid with large electric conductivity past a cylindrical obstacle. The magnetic field is assumed to be so weak that its influence upon the flow may be neglected. The analysis has revealed the following features: The magnetic field outside the cylinder is aligned with the flow owing to high conductivity of the fluid except in a thin layer along the surface of the cylinder and in a wake behind it. The field inside the cylinder (supposed to be non-conducting) is almost zero, except in the vicinity of the rear stagnation point where the lines of force converge and form a singularity (sink inside and source outside the cylinder) for infinite conductivity of the fluid.

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This paper deals with the steady flow of viscous electrically conducting fluid past a sphere at whose center is loaded a magnetic dipole. The dipole axis is assumed to be parallel to the direction of the uniform flow. The dynamic and magnetic Reynolds numbers of the flow are supposed to be small. The flow field and the drag on the sphere are investigated for both small and large Hartmann numbers. The flow of viscous conducting fluid past a magnetic dipole with no geometrical obstacle is also considered as a limiting case of high Hartmann number flows.

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A first-order theory is presented for turbulence of an electrically conducting fluid in the presence of a uniform magnetic field which is so strong that the non-linear mechanism as well as the dissipation terms are of minor importance compared with the external coupling terms. The response of an initially isotropic turbulence to a suddenly imposed uniform magnetic field is worked out in detail. It is concluded that energies associated with the mechanical and the magnetic modes of turbulence asymptotically approach to the state of equi-partition provided that the macro-scales of the two modes are not widely different. Some numerical discussions are made in connection with the physical relevance of the present theory.

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To find clue to the well-known problem of the discrepancy in the weak Mach reflection, fundamental assumptions on which the three shock theory by von Neumann is based are examined and they are shown to become inadequate as the shock waves become weaker. With use of this fact, the three shock theory is modified, giving the Mach shock angles consistent with the experimental values. For further study, an approach to utilize the flow field near the triple point is suggested and proves to give the angle values which agree well with the experimental data.

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On the basis of a reduced equation for steady, two-dimensional flow of a perfectly conducting gas with an aligned magnetic field, the M²⁻ expansion method as well as the thin-wing expansion method is extended to include the effect of a magnetic field.
General formulae obtained by both methods remain unchanged, except that the parameters involved should be read as given in the paper.
The transonic thin-airfoil theory is also modified for magneto-hydro-dynamical flow and it is found that the same similarity rule for the flow past a slender body holds for both non-magnetic and magnetic cases with the proper alteration of the parameters.

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The Hall effect is shown to induce a swirling or transverse motion in the flow of an electrically conducting gas in a magnetic field and surrounded by an insulating medium. Both the two-dimmensional and the axi-symmetric flows are discussed.
On the assumption that the magnetic Reynolds number and the magnetic interaction parameter are small, the transverse or helical velocity is shown to be independent of the Mach number to first order approximation. This velocity is explicitly determined for a slender symmetric flow with small Hall parameter in terms of the imposed magnetic field along the axis. A numerical example is given for a magnetic field of a single current loop.

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The problem of an infinite flat plate set impulsively into uniform motion in its own plane in an infinite mass of fluid is discussed using the B-G-K model of the Boltzmann equation. The velocity of the plate is assumed to be small and the equations as well as the boundary conditions are linearized. The velocity field and the stress on the plate are obtained for both short and long times. For short times the solution represents a perturbation to the linearized free molecular flow. It involves also at long times essential difference from the classical slip flow near the boundary.

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A new method of treating the two-dimensional steady flow of a viscous fluid past an arbitrary cylindrical body is presented. On the basis of the Oseen approximation, a set of integral equations is derived for the values of the vorticity and its normal derivative on the surface of the cylinder. Once these values are found, the velocity in the flow field as well as the drag, lift and moment acting on the cylinder can be calculated. The method is applied to the calculation of the drag of a circular and an elliptic cylinder. An analytical expression in a power series of the Reynolds number is obtained for the drag of a circular cylinder, which agrees completely with the known result. The numerical results are also in satisfactory agreement with those by other authors.

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It is the purpose of this paper to investigate the steady slow motion of an incompressible viscous fluid through a tapered tube, and to examine theoretically the dependence of the distribution of shear stress on the semi-angle of the cone. The volume of flow per unit time has also been calculated and a formula corresponding to the Poiseuille’s equation has been obtained. In our calculations it is assumed that the velocity of the liquid is so small that the inertia term in the Navier-Stokes equations of motion can be neglected.

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p. 713   For Eq. (3),   “F(h0·l)=F(\barh0·l)=−F(h0·\barl)=−F(\barh0·\barl)”
read   “F(h0·l)=F(\barh0·\barl)=−F(\barh0·l)=−F(h0·\barl)”

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Page 920, column 1, 10th–6th lines from the bottom:   primitiveness represents the smoothness in symmetry, while order represents the smoothness in free energy.
Table IV, 2nd column, 3rd line:   Pcca(Pccb),
10th line:   , Pnna(Pnnb),
The last line:   Fddd
Table V, 3rd column, 6th line from the bottom:   P4₂⁄nmc
5th line from the bottom:   P4₂⁄nbc
Page 920, column 1, 16th–17th lines:   conveni-ent

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