Stimulated by a computer simulation of a plasma flute mode, we develop a theoretical argument to show that a single-wavelength, unstable flute mode, $\omega \ne {\omega }_c$, will nonlinearly shift some of its energy to the nearest cyclotron harmonics.

The frequency and temperature dependence of proton relaxation times have been measured for the nematic liquid-crystal and isotropic liquid phases of $p$-azoxyanisole and $p$-azoxyphenetole as well as for the "neat" mesophase of sodium stearate. Self-diffusion coefficients were determined by the proton-spin-echo method. The anomalous effects found are interpreted in terms of collective long-range-order fluctuations in the nematic region and a residual order in the isotropic liquid.

Overlapping pseudopotentials $v\left(q\right)\mathrm{}$ correspond to mean minimal muffin-tin potentials $v\left(q\right)a\left(q\right)\mathrm{}$, where $a\left(q\right)\mathrm{}$ is the liquid-metal structure factor. Potentials thus derived are consistent with data fitted to observed Fermi-surface anisotropies in the alkali solids.

The magnetic-field-induced circular polarization of the Tl characteristic emission in KI: Tl has been studied. The large size of the effect and its temperature dependence indicate that the emitting state sampled by our measurement is nearly degenerate. The data obtained support the theory on ${\mathrm{Tl}}^{+}$ luminescence in alkali halides recently proposed by Fukuda.

Photoconductivity measurements in the infrared and visible spectral regions have been made on disordered NiO Films. The result shows a prominent peak at the energy of 0.23 eV, coinciding with the one in the infrared absorption, which is believed to be a spin-excited state due to the antiferromagnetic ordering. We propose a model to explain the observation.

Thermal expansion and magnetostriction measurements on single-$\overrightarrow{\mathrm{Q}}$ single-crystal chromium give the lattice parameter ratios in the orthorhombic phase below the Néel temperature and through the transition to the tetragonal phase at the spin-flip temperature, $T_F=122\mathrm{}°$K. The $\overrightarrow{\mathrm{Q}}$ direction is the longest axis at 300°K and becomes the shortest axis below ∼200°K. The anisotropic discontinuities in length at $T_F$ result in a net volume dilatation, 1.4 × ${10}^{-6\mathrm{}}$ with decreasing temperature.

A detailed shell-model description of ${\mathrm{F}}^{18}$ and ${\mathrm{O}}^{18}$ is given for all levels of known spin and parity. New assignments are suggested. It is shown that a weak-coupling model is highly successful in reproducing the exact results.

It is pointed out that the existence of a neutrinoless $\beta$-decay process would provide a basis for the customary assumption that the number of neutrinos and antineutrinos is equal in the universe.

Angular distribution of muon-poor extensive air showers was found to be flatter than that of normal showers. The result excludes any possibility that muon-poor showers are initiated by primary photons. It is likely that the showers are generated by some relatively passive particles which are produced through interactions between the primary cosmic rays and the atmospheric nuclei.

The elastic and total cross sections for deuteron-deuteron interactions at 680, 920, 1180, 1500, 1750, and 2120 MeV/c are presented. The data are compared with theoretical calculations and shown to be in qualitative agreement with predictions based on the Glauber multiple-scattering formalism. In particular the existence of large-angle deuteron-deuteron elastic scattering provides evidence for the "simultaneous" scattering amplitudes predicted by the Glauber theory.

We report a measurement of the total and differential cross sections and ${\Delta }^{++}$-decay angular distributions for the reaction ${\pi }^{+}p\to {\pi }^0{\Delta }^{++}$ at incident momenta between 2.67 and 4.08 GeV/c. A dip near $t=-0.5\mathrm{}$ and a backward peak are clearly observed. In a Reggepole exchange model we determine the parameters of the $\rho$ trajectory.

For several Regge trajectories of elementary particles, we exhibit formula fits to the experimental masses. We find that it may be premature to conclude that even the existing trajectories form straight lines when the squares of the particle masses are plotted against the particle spins.

A rigorous method is presented to obtain the velocity distribution function $F(c, \theta )$ for free electrons in gases in quasistationary and quasiuniform cases. It is based on the introduction of a particular distribution function $f_0\left(c_0\right)$ relevant to the "initial" speeds of successive paths taken by an electron. The "usual" distribution function $F(c, \theta )$ can then be obtained from the "initial" distribution function $f_0\left(c_0\right)$ by an integration.

We discuss the explosive instability caused by the nonlinear interaction of two positive energy waves and one negative energy wave and its stabilization by higher-order nonlinear effects.

The $\frac{1}{f}$ noise on etched silicon surfaces can be influenced by adsorption and desorption of water and by heating processes. The observed time constants are the same as the constants of chemisorption. In particular a correlation of $\frac{1}{f}$ noise to the density of active centers of chemisorption is found.

We present measurements of the pressure derivative $\frac{d\left(\ln S\right)}{\mathrm{dp}}$ of the Fermi surface cross section $S$ at [100] and [111] for the electrons in Pd and Pt in the range 0-25 atm. The results suggest that the electron pressure derivatives in these metals are nearly isotropic. Along [100] $\frac{d\left(\ln S\right)}{\mathrm{dp}}=(4.0\mathrm{}\pm 0.4)\times {10}^{-4\mathrm{}} \mathrm{and} (3.2\mathrm{}\pm 0.3)\times {10}^{-4\mathrm{}}$ ${\mathrm{kbar}}^{-1\mathrm{}}$ for Pd and Pt, respectively.

By using a thin NiO single-crystal sample, it has been possible to observe electroreflectance spectra between 3.0 and 5.0 eV. The results of this study and a recent photoconductivity investigation suggest that an energy-band description which includes the $3d$ electrons is necessary for a full description of NiO interband optical properties.

Thin walls of mobile dislocations have been produced. When stimulated by a plane ultransonic wave, the cylindrical waves radiated from each dislocation are all in phase and produce a plane radiated wave. As each dislocation contributes in the same way, the detected macroscopic plane wave directly measures the microscopic motion of individual dislocations. Radiation-induced pinning-point changes and orientation effects are evidence that the signal comes from moving and not from static dislocations.

Raman scattering data are reported for ${\mathrm{Tl}}^{+}$ impurities in KCl, KBr, and KI. Strong lines of $E_{\mathrm{g}}$ symmetry and weaker lines of $A_{1\mathrm{g}}$, $E_{\mathrm{g}}$, and $T_{2\mathrm{g}}$ symmetry are observed. Theoretical calculations based on breathing-shell-model phonons, with no impurity-induced change in force constants, are seen to be in agreement with the data. It appears that ${\mathrm{Tl}}^{+}$ acts as an isotopic impurity and allows one to use the Raman effect as a direct probe of the pure-crystal phonons.

We discuss a new approach to the study of the Suhl-Nakamura interaction in ferromagnets. The method, which consists of varying the Suhl-Nakamura range function by applying an external magnetic field and observing its effects on the nuclear $\frac{1}{T_2}$, was utilized to study the Suhl-Nakamura interaction in ferromagnetic Co.