We develop the lattice theory of liquid state by using the cell model of lattice type with interstitial sublattices. The free energy, the pressure, and the quantities at the critical point are calculated in the degree of quasi-chemical approximation. The degree of agreement of the calculated values of τ_c, v_c⁄v₀ and p_cv₀⁄ε with their observed values is considerably improved as compared with those calculated values for the cell model of lattice type with no sublattice.

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Growth spirals were observed on the (001) and {111} surfaces of WO₃ crystals which were prepared by sublimation. Spirals on (001) are of ‘circular symmetry’, but spirals on {111} are of a characteristic shape which is explained by crystal structure. It was found that in any one region of the crystal the dislocations were not only predominantly of the same sign but also had the same strength. The movement of dislocation has been illustrated. Besides these spirals the layer formation from edges or corners of crystals was observed.

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The effect of the condition of crystallization on the domain pattern was studied by a polarization microscope. Slow crystallization at the temperatures between two Curie points gave domains parallel to the b-axis, whereas above the upper Curie point they were parallel to the c-axis. On raising temperature through the upper Curie point, monoclinicity decreased gradually, without any change of domain width, until the domain pattern disappeared at 24.25°±0.2°C, where a marked pyroelectricity and a maximum of permittivity were observed. The pyroelectric effect continued to exist up to a temperature a little higher. Annealing crystals in the atmosphere of appropriate humidity had no effect on the domain formation. This fact, together with the fact that the crystallization between two Curie points brought about the splitting into domains seems to show that the domain formation is mainly governed by elastic energy rather than electrostatic energy. Explanations of observed phenomena are presented.

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The present situation of the exciton problem is discussed briefly. The localized excitons of KCl in both optical and X-ray absorption have been worked by using Wannier-Slater’s equation for the perturbed lattice, which may be considered to essentially correspond to the quantum-analogue of von Hippel’s semi-classical model of the exciton. The perturbing potential fields in Wannier-Slater’s equation are evaluated numerically by the use of Hartree’s data and then the best-fit analytical functions are constructed with fair accuracy. The solutions of the equation are worked by the variational method. The result for the optical exciton is observed to be in fair agreement with the experiment. As for the X-ray exciton, the quantitative comparison with our results can hardly be carried out at present, since the position of the bottom of conduction band can not be measured accurately on the X-ray absorption spectra. On the basis of our results for X-ray exciton, however, some discussions on the characteristic structure near the absorption edge in KCl are presented.

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The cohesive energy of zincblende has been calculated quantum mechanically by introducing a covalency correction into the usual pure ionic binding. The cohesive energy per ion-pair thus obtained is 1.46 in atomic unit which is very near the observed value 1.36 derived by means of Born-Harber’s energy cycle, and is certainly greater than the value calculated for purely ionic binding by about 60%.
This method of calculation would be generally applicable not only for sphalerite-type crystals but also for wurzite-type ones.

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When self-diffusion takes places rapidly in solid hydrogen contaminated with oxygen, the ortho-para conversion rate is enhanced. The ortho-concentration follows the diffusion equation including the effect of the oxygen; by finding the steady state solution of this equation and using values of the relaxation time, τ, associated with the self-diffusion, which were measured recently by Rollin and Watson, we can conclude that below 4°K the effect of the self-diffusion is negligible and above 8°K the self-diffusion is so rapid that it smoothes out the ortho-concentration around each oxygen molecule. The rate of ortho-para conversion above 8°K is calculated assuming a uniform ortho-concentration throughout the crystal.

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A method was developed of observing soft X-ray emission spectra directly on the screen of a cathode-ray oscilloscope. Soft X-rays emitted from metals were detected by a photoelectric device which works under retarding voltages having saw-tooth wave form. The photoelectric current was differentiated three times by electronic differentiating circuits. The saw-tooth wave voltage corresponds to the reciprocal of wavelength, while the differentiated photoelectric current represents the intensity of soft X-ray emission. Using this method we obtained the emission spectra in about 1/100 sec, exposure without serious contamination of the anticathode. As an example, the structure of the L₃ emission spectrum of Al was studied.

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The change of magnetic properties due to the replacement of tellurium by selenium in CrTe, which has NiAs structure, was investigated. Ferromagnetism is observed in the concentration range from x=0 to x=0.8, where x is defined by Cr(Te_1−xSe_x). The compounds outside this range are para- or antiferromagnetic. In the paramagnetic range of temperature the Curie-Weiss law is found to be valid. It was also found that the Curie-Weiss constant is independent of concentration in the neighbourhood of CrTe and CrSe respectively, and varies abruptly at the transition concentration from ferro-to antiferromagnetic state. A short discussion are given.

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The thermal and X-ray analyses were carried out for iron-selenium system from 48.8 to 57.4 atomic percent of selenium, such range being previously reported to be ferrimagnetic.It was concluded from the experimental results that at room temperature the concentration range from 48.8 to 53.1% selenium is the two phase region α+β; α has the PbO type structure and β the NiAs type. These two phases transform through a eutectoid reaction into a γ phase with the NiAs structure of slightly different lattice parameters in comparison with those of the β phase, the eutectic temperature being 350°C. The solubility limit in iron side of the phase lies at 53.1% selenium. It is remarkable that the substance with stoichiometric concentration (50% Se) does not lie in the single phase region of NiAs type. It was also found that the ferrimagnetism of this binary system originates from the phase of NiAs type (β phase) and the α phase is weakly paramagnetic or antiferromagnetic.The Curie point of the compound containing 53.1% selenium is 174°C and the spontaneous magnetization at absolute zero of temperature is 0.20 Bohr magneton. This magnitude of magnetization is explained by assuming a kind of the ordered arrangement of ferric ion in the crystal lattice.

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We have measured the chemical shifts, the transverse- and longitudinal-relaxation times of chlorine nuclear magnetic resonance of such liquid chlorine compounds as TiCl₄, VOCl₃, CrO₂Cl₂, and SiCl₄, of which the quadrupole coupling constants were measured by Dehmelt by means of the pure quadrupole resonance experiment. Our results were considered in view of the correlation to quadrupole coupling constant. Line widths are nearly proportional to the square of the quadrupole coupling constant. The equality of the transverse relaxation time T₂ and the longitudinal relaxation time T₁ has been verified experimentally in these compounds. Solomon’s method for the calculation of T₁ and T₂ was applied to a quadrupole relaxation. T₁ is exactly equal to T₂ in cases where quadrupole relaxation is essential, the molecular surroundings are isotropic, and further the extreme narrow conditions are well established. This result is identical to Wangsness and Bloch’s. Experimental T₁ values are about ten times larger than the theoretical one and the reason of the discrepancy is discussed. In Appendix, estimation of chemical shift by d-electron is given.

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1. Total yield, γ, and energy distribution were calculated for electrons ejected from BaO by inert gas ions, on the basis of the theory of Auger neutralization. The method used here was similar to Hagstrum’s one for tungsten. Total electron yield, γ, are found to be 0.481, 0.480, 0.476, 0.474, and 0.471 for He⁺, Ne⁺, Ar⁺, Kr⁺, and Xe⁺ ions of several electron volts (ev), respectively. The electrons ejected from BaO have unexpectedly high energy and narrow distribution in comparison with those from tungsten observed by Hagstrum. In the case of Ar⁺ ion, the calculated value of total electron yield, γ, is in good agreement with the Varney’s measurements, and the high energy of ejected electrons is just as he expected.
2. The cathodic phenomena (cathode fall, width of Crookes dark space, and current density) in the normal glow discharges were observed for He, Ne, Ar, and Xe gases with BaO-coated cathode and tungsten, and were interpreted by the von Engel and Steenbeck’s theory using the calculated values of γ for BaO and the observed one by Hagstrum for tungsten.

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The steady slow motion of a viscous fluid past two parallel circular cylinders C₁, C₂ of arbitrary radii is discussed on the basis of Oseen’s linearized equations of motion, confining ourselves to the case when their axes are perpendicular to a uniform flow. The forces acting on the cylinder C₁ are calculated to the first approximation.
By performing detailed numerical calculations, a discussion is made on the manner in which the forces acting on the cylinder C₁ is modified by the presence of the other cylinder C₂.
It is thus found that, as the radius of the cylinder C₂ increases, the drag on the cylinder C₁ decreases, while the lift increases. It is also found that the cylinder C₁ experiences smaller drag when the two cylinders are in tandem orientation than when they are placed side by side in a uniform stream. Especially, when the cylinder C₁ is situated behind the cylinder C₂, it experiences smaller drag than when it is situated in front of C₂.

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Transition of two-dimensional separated layer was investigated in detail. Mean velocity distribution of laminar layer shows a similar profile and agrees with Lin’s calculation. In the transition region, hot-wire anemometer survey of velocity fluctuation revealed the existence of sinusoidal wave, the frequency of which lies in the unstable zone predicted by stability theory. Transition points determined by layer thickness and by fluctuation measurements are in good coincidence. A simple empirical relation was derived for transition distance.

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The flow past a flat plate accompanied with an unsymmetric dead air, especially the flow past such a flat plate with a small angle of attack at Mach number 1, is investigated, using Imai’s WKB method. Comparing the results with those of Guderley and of Truitt, it is ascertained that these agree fairly well with each other. It may be concluded that the dead air model is useful for the study of the transonic flow.

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