The phase relations of the system Na(Nb_1−xTa_x)O₃ in the solid state are studied by means of the dielectric constant measurements, x-ray diffraction studies and optical observations.
The transition point vs. composition curve of this system exhibits a discontinuity in 0.55>x>0.54. The solid solutions with the composition range x≤0.54 show two transition temperatures, one of which was determined by the dielectric measurements and the other by the optical means. These two transition temperatures increase with increasing value of x showing a maximum near x=0.1, and then decrease monotonically. The room temperature phase is antiferroelectric in this range.
On the other hand, in the range x≥0.55 the dielectric anomaly corresponding to the ferroelectric Curie point exists below room temperature and it decreases monotonically with increasing value of x. Any dielectric anomaly, however, is not found in NaTaO₃, and it may not be ferroelectric down to liquid helium temperature. Other three transitions at higher temperatures are observed only by optical means.

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The effect of uniaxial compression along [111] on impurity conduction has been investigated in n-type germanium with intermediate concentration and with different compensation ratios. Activation energy of resistivity for compensated samples of antimony-doped germanium does not change with stress and is determined by the spacial configuration of impurities and by the extent of wave function derived from one valley.
Magnetoresistance has been measured as a function of stress. Temperature dependence and anisotropy of positive magnetoresistance can be interpreted as modification of wave functions by a magnetic field. Negative magnetoresistance has been observed in most samples used and shows large anisotropy under stress. In the case of p-type germanium, which shows no negative magnetoresistance without stress, negative magnetoresistance is also observed under [100] compression.

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Defects in quenched and aged aluminum of various purities are studied. Almost all dislocation loops which are formed by the vacancy condensation in pure aluminum are Frank sessile type, containing a stacking fault. The shape of the Frank sessile dislocation loops is hexagonai on {111} plane bounded by ⟨110⟩ directions. The annealing process of these dislocation loops and the change from Frank sessile dislocation loops to prismatic ones are studied experimentally. Discussions are given on the formation of Frank sessile dislocation loops and their change into prismatic dislocation loops.

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The Zeeman splitting for Cl³⁵ quadrupole resonance in a single crystal Ba(ClO₃)₂·H₂O in a high magnetic field (about 6000 oe) was studied in detail by using the proton signal enhancement due to a crossing of the quadrupole resonance frequencies of chlorine nuclei and the magnetic resonance frequencies of protons.
The parameters of Ba¹³⁵ and Ba¹³⁷ quadrupole resonances in a Ba(ClO₃)₂·H₂O were obtained, using the crossing technique:
1 ν(Ba¹³⁷)=13.18±0.01 Mc.
ν(Ba¹³⁵)=8.55±0.01 Mc. \ aisebox6ptat 15.5°C, \fracQ¹³⁷Q¹³⁵=1.542±0.002
2 Asymmetry parameter, η=0.480±0.004
3 The direction angles of the principal axes x, y, z, of field gradient tensor with respect to crystal axes a, b, c, are (123±3°, 90°, 30±3°), (33±3°, 90°, −60±3°), and (90°, 0°, 90°) respectively.
4 The temperature coefiicient of frequency, 1⁄ν_Q·dν_Q⁄dT, is 1.04×10⁻³ deg⁻¹ for the temperature range from 20°C to 70°C.

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On the assumption that each Ho⁺³ ion has the two lowest lying levels, the temperature dependence of the spontaneous magnetization of HoN is discussed by a spin wave approximation. The approximate spin wave functions considered in the present study are so constructed as to include the basal wave functions for the one ion Hamiltonian composed of the terms of the cubic crystalline fields and the effective exchange field parallel to ⟨100⟩. This numerical computations are carried out by using the numerical data of previous papers. Due to the partial quenching of the angular momentum, the averaged z-component of the total angular momentum J over these wave functions is found to be reduced essentially from J=8 in free state. The temperature dependence of the spontaneous magnetization of HoN departs from the usual Bloch T^3⁄2 law and is well in accordance with the experimental data.

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The properties of the dielectric constants, defined by using many-body theory, are considered. Especially, their dependence upon wave vectors is discussed. Internal dielectric constant for impurity potential in an insulator is shown to have no anomalous behavior at reciprocal lattice vectors. It is also shown that contribution to the dielectric constant from Umklapp terms vanishes at k=0.

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The relation between the surface plasma oscillations and the homogeneous (radiation) solutions of Maxwell equations in thin metallic films is discussed. The expression for the total energy loss characteristic in the bounded medium is also derived by using the inhomogeneous and homogeneous fields thus obtained. The deduction proposed by Kunz that the energy loss observed in silver is caused by the excitation of surface plasmons is investigated by carrying out the numerical calculation of the expression for the total energy loss.

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The resonance absorption of the incident light in thin metal films, which is to be considered as an example of the so-called plasma resonance, is studied. This absorption is caused by the mechanism proposed by Ferrell, namely, by the excitation of surface (bounded) plasmons by light and therefore corresponds to an inverse process of the transition radiation. The reflectivity and the transmission coefficient in the case of silver are numerically calculated by using its dielectric constant obtained experimentally by Taft and Philipp and are compared with the experimental results given by Yamaguchi.

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Excess carrier lifetimes are calculated under steady state conditions with explicit considerations for transitions between the various states of a multi-charged center. The results obtained are of nearly the same forms as in the usual theory in so far as a phenomenological treatment is concerned. Apparent capture probabilities of the center can be represented by probabilities of various elementary processes, and correspond to total conductances of a certain equivalent circuit. Basing upon these formulae, some studies of dynamical processes are made, and possibilities of relatively large capture cross section of repulsive centers as well as attractive ones are obtained.

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Primary photoconductivity has been investigated in single crystals of TlCl. Measurements are made mainly in a wavelength region of the first exciton band and near liquid nitrogen temperature. The quantum efficiency for producing free electrons is found to be somewhat dependent on wavelength in the region of the exciton band. This dependence suggests that the life time of an exciton is very short and the exciton decomposes into an electron and a hole before it achieves equilibrium with the lattice. The Schubweg of a hole is obtained to be about one hundredth of that of an electron at 103°K. Properties of electron-trapping centers effective above 100°K are also investigated.

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Two problems concerning strain effects on isolated donor states in Si and Ge are treated. One is a modulation of the hyperfine coupling between the donor electronic and nuclear spins which gives rise to a cross relaxation rate T_x⁻¹(Δm_s=±1, Δm_I=\mp1). For Raman process (double-phonon process) T_x⁻¹ is shown to depend on the temperature as T⁻⁷. For P-donor in Si the calculated value of T_x is approximately 1.5×10⁴ second at T=2.16°K, which is in good agreement with the experiments of Honig and Stupp. For single-phonon process the calculation shows that T_x is sensitive to static strains in the crystal, which has been confirmed in the experiments of Wilson and Feher. The other problem treated is the effects of strong external stresses on Ge donor spin-resonance lines. The electronic g-tensor, the single-phonon relaxation rates T_s⁻¹ and T_x⁻¹, and an inhomogenous broadening effect are derived for several orientations of the stress and the magnetic field. It is shown that both T_s and T_x can be made longer than 1 second by applying a large compression along the ⟨111⟩ direction within experimentally available conditions.

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Electronic specific heat of Pd is deduced from the experimental data. Using the density of electronic states of Pd which has been determined from the low temperature specific heat data of Pd–Ag and Pd–Rh alloys and Ru metal by assuming the rigid band model, the electronic specific heat and the spin paramagnetic susceptibility of Pd are calculated at arbitrary temperatures. The calculated result for the temperature dependence of the electronic specific heat of Pd satisfactorily agrees with the experimental result, whereas the calculated values for spin paramagnetic susceptibility are considerably smaller than the observed values. The main difference will be attributable to the effect of the molecular field. The maximum in observed magnetic susceptibility at about 80°K can be explained by considering a peculiar band shape.
Similar calculations to those for Pd metal are performed for Pd–Ag and Pd–Rh alloys.

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A molecular theoretical investigation about the relaxation spectrum of high polymeric substances within the range of long relaxation time has been pursued using a temporarily crosslinked network model, in which crosslinkages are created by the secondary valence of segments or by the entanglement of polymer molecules. Each chain is considered to be Gaussian and the so-called Rouse model corresponding to the macro-Brownian motion is set up. With use of the Rouse model and the concept of slipping of chains a theory is presented.
The relaxation spectrum predicted by the theory is of the box type and the steady flow viscosity coefficient is proportional to the 3.4 power of molecular weight.

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The rate of energy loss of a charged particle moving fast through a plasma in a magnetic field is obtained exactly without any cut-off procedures. The stopping power decreases as the magnetic field is increased. Some limiting cases are treated analytically, but general cases are investigated with numerical calculations.

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An experimental work is presented to examine the previous analysis by T. Dote et al., for the estimation of positive ion density in the ionosphere from the ion current obtained by a rocket-borne Langmuir probe.
The plasma was formed in a low-density supersonic wind tunnel, where the probe characteristics were measured. The drift Mach number, the pressure and the temperature of the plasma were 3, 86 microns Hg and 107°K respectively.
It is indicated that the values of positive ion density estimated by the previous analysis are nearly equal to the values of electron density obtained from the electron saturation current characteristics which are considered to be almost independent of the supersonic drifting of plasma.

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A new method to determine directly the Im 1/ε-spectrum is proposed. The Im 1/ε-spectrum is observed as the absorption spectrum due to polarization normal to the film. The method is applied to silver films. The observed Im 1/ε-spectrum differs from the Im 1/ε-spectrum calculated from the optical constants which are determined relating to polarization parallel to the film as follows: the peak heights for both spectra are in accord, but the peak position of the observed spectrum 3.79 eV is in slightly high energy side of the peak position of the calculated spectrum 3.77 eV, and the observed width of half maximum 0.1 eV is about 2/3 times narrower than that for the calculated spectrum. From phenomenological consideration, the real part of dielectric constant must have large anisotropy.

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The diffraction of electromagnetic waves by a conducting circular disc is investigated according to a method developed by Y. Nomura, et al. in the particular case where the incident wave is coming from an electric dipole which is placed at a finite distance from the disc and polarized parallel to the disc surface. The solution for the diffraction by an aperture with a magnetic dipole as a source is easily obtained by the application of Babinet’s principle. Various physical quantities are evaluated for several distances between the disc and the dipole which is placed on the central axis of the disc. When the dipole is apart from the disc about five times of the radius, curves of the physical quantities resemble very much those for the normal incidence of plane waves.

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This paper is concerned with the stability of a two-dimensional laminer wake. The development of small disturbances excited artificially is investigated both experimentally and theoretically.
Experiments are made in an experimental water-tank at Reynolds numbers between 10 and 600 for a flat plate and between 0.8 and 60 for a circular cylinder. The amplification rate, the wave length and the wave velocity of the disturbance are measured from the photographs of the flow. The neutral stability curve is determined both for the fiat plate and for the circular cylinder. The minimum critical Reynolds number below which all disturbances are damped is found to be about 1.0 for the circular cylinder.
Theoretical investigations are made by the method of small oscillations. The agreement between the theory and the experiment is fairly good.

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The two-dimensional and axially symmetrical supersonic jets of an ideal dissociating gas with finite reaction rate are considered on the basis of the linearized theory. Basing on the fact that δ≡(M_e²−M_f²)⁄(M_f²−1) (M_f and M_e denote respectively the frozen and equilibrium Mach numbers) is always sufficiently small, an approximate method of analysis is developed. Changes of the shape and the axial velocity distribution of the jet due to variations of the parameter δ and the reaction rate are investigated in detail. Owing to the finite reaction rate, the jet has the wavy configuration damping toward downstream and tends to the equilibrium, uniform flow at infinity downstream. According as the reaction rate changes from zero to infinity, the possible transition of the jet structure from the inert to the equilibrium limit can be found.

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