The problem of the scattering of lattice waves by the static strain field of dislocations has been treated by means of the Green’s function method. The calculation starts from the force constant model like that of Carruthers, the relaxation time obtained is, however, about one hundredth of that evaluated by him. For the case of longitudinal waves scattered by edge dislocations in alkali halides, MgO, Cu and Ge, the scattering cross sections calculated by the present theory exhibit fairly better agreement with the experimental results as compared with those calculated by Klemens and Carruthers.

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Magnetic measurements indicate that Ca₂Fe₂O₅ is an antiferromagnet, with weak parasitic ferromagnetism. The lattice, with the space group Pcmn-D_2h¹⁶, can be considered as an oxygen deficient perovskite. The magnetic structure as determined from a neutron diffraction study is of G-type, and Fe³⁺ spins are directed approximately along c-axis.

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Nuclear magnetic and quadrupole resonances were used to study the structure of hydrogen and deuterium chlorides below and above the transition points. The chlorine pure quadrupole resonance frequencies were measured between 20°K and the transition points, showing that a single molecular libration frequency does not fully account for the temperature dependence probably because of the effect of intermolecular hydrogen bonds. The structure of the high temperature phase was proposed as being a hindered rotational one, on the basis of the second moment of the proton magnetic resonance and of the direct observation of chlorine magnetic resonance, the latter leading to the activation energy of 0.7 kcal/mole for rotation. The self-diffusion of molecules below the melting point causes further narrowing of proton resonance line above 130°K, with an activation energy of 5.6 kcal/mole.

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Plastic deformtion of quenched gold is found to enhance the formation of stacking fault tetrahedra. The experimental results on the effect of deformation during the two step aging indicate that the enhanced nucleation of tetrahedra is not caused directly by the deformation, such as by the geometrical reaction between glide dislocations, but occurs during aging after deformation. The variation of the influence of deformation with the concentration of quenched-in vacancies denies other possibilities than the enhanced nucleation caused by the localized vacancies produced by jogs on moving dislocations. The mechanism for the appearance of tetrahedra in straight rows along ⟨110⟩ is clarified. The influence of deformation on the formation of vacancy clustered defects is compared between quenched gold and aluminum.

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A novel technique in positron annihilation (J. Phys. Soc. Japan 20 (1965) 1533, 21 (1966) 1947) enabled us to survey the Fermi surfaces of the α-phase alloys in the system Cu–Al. The results were as follows:
1. The neck radius does not increase monotonically with increasing content of Al, but shows an oscillatory behaviour having a maximum at 2∼3 at.% Al and a minimum at 5∼6 at.% Al.
2. For the alloys containing Al more than about 10 at.%, the necks protrude beyond the hexagonal zone faces.
3. The Fermi surface swells out gradually in the ⟨200⟩-directions with the addition of Al atoms.
4. A possible model of the Fermi surface was proposed for 10.6 at.%-alloy by taking account of four angular-correlation curves corresponding to different orientations of crystals.

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An anomaly has been found in the current-voltage characteristics of the electron tunnelling in a cross type Sn–SnOx–Pb junction with a small tunnelling resistance and a very thin tin film, which was proved to correspond to the superconducting-to-normal transition in the tin film. Some properties of the anomaly were also examined. It is pointed out that as the electron tunnelling method requires relatively large current through the junction with a small tunnel resistance in order to measure the energy gap directly, the superconducting state of a very thin film is disturbed by this tunnel current.

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There are two modes in magnetoplasma waves in bismuth. One mode rotates in the sense of hole cyclotron motion and the other in electron sense. The weak damping has been observed at the neighbourhood of hole cyclotron field in the latter mode, although it is expected to be insensitive to hole motion in the local scheme. This effect has been interpreted in terms of the little admixture of the hole sensitive mode due to nonlocal effect. This mode mixing cyclotron damping occurs at ω+qv_F>ω_c>ω−qv_F. With use of this relation, the Fermi velocity as well as cyclotron mass of holes in bismuth has been determined from the observed damping region.

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Reflectance spectra of pyrolytic graphite are measured in the range 0.13 to 0.006 eV. The results are analyzed by a Kramers-Kronig relation to determine the complex dielectric constant ε(ω)=ε₁+iε₂ and energy loss function. Structures in ε₂ are all identified with interband transitions between the doubly degenerate levels at the points K and H of the Brillouin zone split by the effect of spin-orbit interaction. From the above fact, the strength of the coupling λ and the band parameter Δ are estimated as 0.004 eV (at the point K) or 0.0023 eV (at the point H) and -0.016 eV, respectively. Two peaks observed in -Im ε⁻¹ are interpreted as plasma frequencies of free electrons at the Fermi surface perpendicular and parallel to the crystallographic c axis.

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The conductivities of 1.2, 7.9 and 12.6 ppm (weight ratio) Li-substituted NiO are measured at high frequencies up to 24 GHz in the temperature range 110° to 450°K. The conductivity at high frequencies can be expressed as the sum of a temperature-dependent conductivity σ₁ and a temperature-independent additive conductivity σ₂. The former σ₁ is independent of frequency until microwave region but the latter σ₂ is strongly dependent on freqnency. The frequency dependence of σ₂ can be represented by the dispersion formula for the dielectric loss due to the hopping of charge carriers around imperfections. The staying time at a lattice site is determined: τ=2.2×10⁻¹⁰ sec. A lack of temperature dependence of σ₂ implies that the staying time τ does not depend on temperature and further that the holes are not selftrapped. The conduction mechanism in NiO is rather illustrated as something analogous to impurity conduction.

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Dynamical aspects of the ferroelectric phase transition in KH₂PO₄-type crystals are elucidated on the basis of the coupling between the proton tunneling mode and the optical mode vibration of the [K-PO₄] complexes along the c-axis. Two coupled modes are obtained within the framework of a linear theory. The mode in which both systems oscillate in phase is shown to be responsible for the ferroelectric phase transition. The isotope effect in the Curie point is explained qualitatively and the Curie constant is estimated.

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Hall measurement has been carried out for a set of p-type Ge–Si single crystal alloys. From the Hall mobility data, an expression for alloy scattering is derived for holes. Its temperature dependence considerably deviates from the theories by Nordheim and Brooks. Low temperature measurement indicates a possibility of producing shallow acceptor levels in the alloy crystals.

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A nonlinear theory is given of the current oscillation in semiconducting cadmium sulfide at room temperature when the drift velocity of electrons exceeds the velocity of sound. It is assumed that a high field domain of a rectangular shape due to the amplification of thermal phonons builds up near the cathode and travels with the sound velocity toward the anode without changing the domain width, while the region outside the domain remains ohmic. The electrons and phonons inside the domain are assumed to obey the nonlinear coupled equations employed in the discussion of current saturation in a previous paper. When reasonable values of the domain width and the “nonlinear relaxation time” of amplified phonons are chosen, the theory explains semiquantitatively (1) the wave form of current oscillation, (2) the negative resistance in current-voltage characteristics, and (3) the time dependence of electric field distribution in the sample.

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The excess electron and hole band structures of naphthalene have been calculated by the tight binding approximation, in which the molecular wavefunctions are represented by the LCAO functions orthogonalized to 1s AO of the hydrogen atoms in the surrounding molecules. The effect of hydrogen 1s AO to the band widths amounts to 10⁻³ eV, and they are not much different from the result of Katz et al.. The accidental degeneracy is removed in the k//c⁻¹ direction.

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The change in the photoconductivity of KCl crystals containing F centers upon optical bleaching of the F band has been investigated at low temperature. It was shown that the presence of M centers is not responsible for the residue of the photoconductivity in the F band region at low temperature. F′ centers were produced through a tunneling process when F centers were optically excited at low temperature. The quantum yield of the process was dependent on the concentration of F centers and was estimated to be less than 0.06 in a specimen containing 6×10¹⁶ cm⁻³ of F centers. The residual photoconductivity in the F band region at low temperature was found to result not from the absorption of photons in the F band but from the absorption in a band overlapping the F band. The suggested shape and position of the band are given.

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The electron spin resonance of Gd³⁺ has been studied in the orthorhombic and rhombohedral phases of BaTiO₃. The main features of Gd³⁺ resonances are summarized in their relation to Fe³⁺ resonances as follows: (1) The axis of the axial crystalline field in the orthorhombic phase is parallel to the ⟨110⟩ polar axis for Gd³⁺, while this axis is parallel to ⟨001⟩ for Fe³⁺. (2) The magnitude of the axial crystalline field parameter remains almost constant through the three ferroelectric phases for Gd³⁺, while this magnitude for Fe³⁺ almost vanishes in the rhombohedral phase. To explain these differences the electric field gradients at the Ba²⁺ site were calculated and plausible models for the array of the induced electric dipole moments in the surrounding oxygen ions were discussed. Measurements on Eu²⁺ have been also performed in the powder samples of BaTiO₃.

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The polarization characteristics of the blue self-activated luminescence in a cubic ZnS:Al (or Ga) single crystal grown from the melt were investigated. The polarization with particular azimuthal dependences is observed only when the polarized characteristic excitation is given. This indicates that the center has its own characteristic symmetry which is lower than that of the host lattice. The polarization spectra show two maxima with positive values and a minimum with negative values. The results are interpreted according to the associated center model proposed by Prener and Williams, as in the case of the self-activated luminescence of ZnS:Cl, i.e. the model that the center is a zinc ion vacancy associated with an aluminum ion at one of the nearest neighbor cation sites. Discussions on the luminescence transition are given on the basis of group theory. The luminescence is ascribed to a dipole lying in the mirror plane of the center (|| dipole) with the C_s symmetry.

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Fundamental absorption bands of water are studied in its various phases. Cubic ice has a well-defined absorption band at about 8.7 eV, while hexagonal and amorphous ices show only a gradual increase of absorption intensity toward the higher energy in the range from 7 to 10 eV. Absorption coefficient of liquid water is found to comply with Urbach rule at the low energy tail of the fundamental absorption.

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Approximate solutions of the effective mass Schrödinger equation for donor states in gallium phosphide are calculated by a variational method with a parameter γ=m_⊥⁄m_⁄⁄. Comparison of the calculated energies of p-like states of donor with the experimental energy separations between several excited states from the “two-electron” recombination radiation of excitons bound to neutral donors by Dean et al., determines the transverse mass m_⊥=(0.21±0.01)m₀ and the longitudinal mass m_⁄⁄=(1.15±0.05)m₀ at the bottom of the conduction band in gallium phosphide.

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A theory of normal and abnormal absorptions in electron diffraction is presented on the basis of the calculation of the transition probability. The normal and abnormal absorption coefficients are shown to be expressible in terms of the so-called “energy-loss function”, or Im −1⁄η(ω), where η(ω) is the complex dielectric constant for the crystal. The values μ₀, the normal absorption coefficient, and Δμ_h, the abnormal absorption coefficient, are calculated numerically for Si at 50 keV, 67 keV and 100 keV of incident electrons, and the results are compared with experimental data.

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The alpha-particle-induced scintillation of high pressure helium gas has been studied experimentally in the pressure range of 10 to 70 atm with an electric field applied in the region of the alpha tracks. Simultaneously with observation of the scintillation light yield, the ion current extracted from the alpha tracks by the field was measured. The results indicate that recombination luminescence increases with pressure and accounts for about 25% of the scintillation light yield at 60 atm. The decay time of the scintillation pulse is less than 0.5 μsec, which is much shorter than the decay time found at lower pressure. To analyze the electric field and pressure dependences of the light yield, the Jaffé theory was applied to diffusion and recombination of ions and electrons produced along the alpha tracks. The result shows that the pressure dependence of the recombination luminescence can be interpreted in terms of dissociative recombination of vibrationally excited He₂⁺ and the recombination leading to scintillation continues during the relaxation of the vibration. Three-body recombination does not seem to play a significant role in the scintillation mechanism.

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The crystal structure of the long period ordered alloy CuAuII has been investigated by X-ray diffraction using an alloy single crystal with the composition of Cu-50 at.%Au. Half of the long period of the alloy has been measured to be 5.0 in units of the fundamental L1₀-type cell, differing from the result of Jehanno and Perio on a polycrystalline alloy. The Fourier synthesis has been made using H, K, 0 type reflections recorded on Weissenberg photographs. Taking into account the information obtained from the synthesis, the structure parameters including atomic coordinates, temperature factor and occupancy ratio of each atomic site have been refined by a modified least squares method. It has been confirmed that atoms are periodically displaced from the normal lattice points of the fundamental cell. Copper atoms shift by distances ranging from 0.079Å to 0.028Å toward the anti-phase boundary and gold atoms by distances ranging from 0.048Å to 0.004Å in the opposite direction. The atomic disordering occurs considerably in the neighborhood of the anti-phase boundary, while it is not much in the center of the antiphase domain.

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The excluded volume effect on intrinsic viscosity of chain polymers is calculated by assuming the equivalent ellipsoid-polymer model suggested in the previous paper with additional assumptions that this polymer model is rigid and impenetrable for solvent flow. The intrinsic viscosity [η] depends on the expansion coefficient α of excluded volume effect through the relation: [η]∝α^2.45 for wide range of α.
The ellipsoidal polymer model used in the calculations is examined by the Monte Carlo calculations. Thus the calculations find that the mean axial ratio of ellipsoid increases almost linearly with the radius of gyration, and its most probable value for random coil chain is about 2.5.
By combining the present result with the previous theory, two empirical relations between intrinsic viscosity and molecular weight of polymer are obtained, and their comparisons with the experimental results on several polystyrene solutions show the qualitative coincidences.

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An experimental study has been made on the optical absorption spectra on the photobleaching process of trapped electron (e_t⁻) produced by photoionization of tryptophan in mixed polar solvents at 77°K. The population of e_t⁻ is decreased on the photobleaching process in these solvents according to the law which can be always expressed as the sum of two first-order decays.
Two kinds of traps formed in the polar solvents have been shown to exist although the explicit mode of the trap is not clear. An assumption is presented that exchange of trapping of electron occurs between two traps on the photobleaching process of e_t⁻.

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Ion cyclotron resonance heating and nonadiabatic trapping of the hydrogen ions are investigated using a magnetic mirror machine with a mirror ratio of 2. A high energy (150–450 eV) and low intensity (500 μA) hydrogen ion beam is injected along the magnetic lines of force and subjected to ion cyclotron resonance heating by a constant frequency (4.5 Mc/s) r.f. electric field at the midplane of the magnetic mirrors.
Nonadiabatic trapping of the atomic and the molecular ions is observed distinctly. More than fifty percent of the injected atomic and molecular ions is reflected by the mirror field, the reflected ions having energies of 300–900 eV.

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The variation of the electrical dc conductivity of a turbulent plasma from a quiescent plasma is observed. The turbulent plasma is produced by applying an external rf voltage to the quiescent uniform plasma. When the external rf frequency is near the electron plasma frequency f_pe, the decrease of the electrical dc conductivity is observed (30% maximum). The decrease is proportional to the square of the external rf voltage and the saturation occurs beyond a certain level of the rf voltage. The decrease of the electrical dc conductivity depends largely on the direction of the externally applied rf field with reference to that of the dc current.

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The decay of 5.5 h ^180mHf was studied with double focusing beta-ray spectrometers. Both internal and external conversion electrons have been measured, for most of gamma transitions in the decay. The corresponding conversion coefficients have been obtained. Three new weak lines have been observed with energies, 547.6±0.5, 772.3±0.7 and 832.0±0.8 keV. A decay scheme consistent with all of our observations was constructed, Arguments for parity mixing in ¹⁸⁰Hf are given. Implications of the results for current nuclear theories are discussed.

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The excited states of ¹⁰⁰Ru were reinvestigated by the decay of ¹⁰⁰Rh. Singles and coincidence (γ–γ, e–γ and γ–γ–γ) gamma spectra were studied with a Ge(Li), two or three NaI(Tl) detectors and a magnetic beta spectrometer. Observed gamma rays were those of 0.447(13), 0.540(100), 0.589(7), 0.67(weak), 0.75(∼4), 0.822(30), 1.035(4), 1.109(21), 1.34(8), 1.362(24), 1.555(28), 1.927(13), 2.375(41), 2.526(4) and 0.511 annihilation radiation (11), where the numbers are energies in MeV and those in parentheses are intensities; the gamma ray of 2.526 MeV was newly found with both a Ge(Li) and a NaI(Tl) detectors. Gamma-gamma angular correlation was studied for almost all coincident gamma-ray pairs. The excited states of ¹⁰⁰Ru deduced by the above experiment are as follows: 0.540(2⁺), 1.362(2⁺), 1.88(3⁺ or 2⁺), 2.11(?), 2.467(2⁻), 2.915(2⁻) and 3.066(?), where the numbers are excitation energies in MeV.

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The excited states of ¹³⁸Ce following the decay of 2.2 hour ¹³⁸Pr were reinvestigated with a Ge(Li) and NaI(T1) detectors. Weak gamma rays of 0.389 and 0.546 MeV, which were reported previously, were confirmed in a Ge(Li) singles and NaI(T1)–NaI(T1) coincidence spectra. Two levels at 2.206 and 2.752 MeV in ¹³⁸Ce are proposed.

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The stability analysis is presented for a film of a viscous, electrically conducting liquid flowing down an inclined plane in the presence of a magnetic field applied perpendicular to the plane which is also electrically conducting. The resulting Orr-Sommerfeld equation is solved by a regular parturbation technique for disturbances of wavelengths large compared with the thickness of the film. Conductivity of the plane is found to delay the onset of instability.

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Overall behaviours of a radiating grey gas bounded by a black infinite plane wall are investigated for small disturbances caused by an implusive change of the wall temperature. On the assumption that molecular dissipation is negligible in the conservation equation and the radiative transfer term in the energy equation can be approximated by the method of kernel substitution, approximate analytical solutions of these equations are obtained which are valid in the four limiting cases of strong and weak radiation, and small and large times. It is found that for large time and for weak radiation the wave front precedes the maximum of pressure. Except this, separation of wave from heat transport part is not very significant for large time, as expected. For small time, formation of an acoustic wave is distinct together with diffusion based on heat transport. For weak radiation and for small time, radiation slip is remarkable.

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The stability of an axisymmetric wake is studied relative to infinitesimal axisymmetric disturbances. The Orr-Sommerfeld equation is solved by an expansion in powers of αR, where α is the non-dimensional wave number and R the Reynolds number with respect to the effective radius and the velocity defect in the center of the wake. The critical Reynolds number is found to be 5.19. The asymptotic behavior of the neutral curve as α→0 is such that R→1.08α⁻¹ and c→0.676.

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