The superconvergent sum rules for helicity-flip and - nonflip amplitudes controlled by only the $R$ trajectory are used to clarify the ghost-eliminating mechanisms.

A test of $T$ invariance in $p-p$ triple scattering has been performed at 430 MeV. The difference in two polarizations which are identical if $T$ is valid was found to be 0.0006 ± 0.0028. The $T$-nonconserving amplitude was found to be less than ½% of the $T$-conserving amplitude. The $T$-nonconserving phase was found to be less than 0.06 of its maximum value.

The results of a partial-wave analysis of $\Sigma -\pi$ final states near 1 BeV are presented.

A theoretical analysis of experimental results on the relaxation induced by Rb-Kr collisions reveals the existence of two very different correlation times. The shorter, of the order of ${10}^{-12\mathrm{}}$ sec, is a kinetic collision time; the longer, ${10}^{-8\mathrm{}}$ sec, reflects the presence of metastable states associated with resonances in Rb-Kr scattering, or of actual Rb-Kr bound states due to three-body collisions.

We have measured in detail the energy loss associated with the flow of superfluid helium near critical velocity through orifices. At certain temperatures a critical velocity is observed for each orifice below which no energy is lost from the flow, and above which a range of velocities is found where the energy loss agrees with the predictions of Feynman concerning the formation of quantized vortex rings whose size is that of the orifice.

The solubility curve has been measured at the saturated vapor pressure down to 0.025°K, and the limiting solubility at absolute zero has been determined to be (6.37 ± 0.05)% ${\mathrm{He}}^3$. Measurements of the density show that at 0°K and small concentration the volume occupied by a ${\mathrm{He}}^3$ atom in solution is 1.284 ± 0.005 times the volume occupied by ${\mathrm{He}}^4$.

Previous work has shown the periodic $\beta =1\mathrm{}$ theta pinch to be marginally stable to the mode $m=1\mathrm{}$ and unstable for all $m>\mathrm{}1\mathrm{}$. We show that such a pinch can be dynamically stabilized for all $m>~1$.

We have observed the reflected second-harmonic intensity generated by an incident beam which is totally reflected by the nonlinear medium immersed in a denser linear medium. The reflected intensity becomes very high near the critical angle for total reflection. The role of momentum matching for the reflected intensity is demonstrated.

The measured electrical conductivity of pure KBr is analyzed into anion and cation components in two ways, and the results compared with those obtained by direct diffusion measurements. It is found that analysis of the conductivity using only the intrinsic region is unreliable and leads to an overestimate of the anion and an underestimate of the cation activation entropy and enthalpy.

The Néel temperature of Cr is found to vary exponentially with volume, which is in support of a two-band model of itinerant antiferromagnetism. The temperature dependence of the magnetic contribution to the electrical resistivity can be explained by taking into account only the variation in the number of effective carriers from the introduction of a band gap ($2\Delta$) due to the magnetic ordering. The ratio $\frac{{\Delta }_0}{k{T}_{\mathrm{N}}}$ is estimated at 2.3 at $P=26\mathrm{}$ kbar.

The observation of internal field emission (Fowler-Nordheim tunneling) in magnetically ordered insulators is reported. A large magnetic field effect was observed and interpreted as a decrease in the barrier height due to spin ordering.

We report the temperature dependence of the Raman spectrum of the soft $E$ mode in single-domain BaTi${\mathrm{O}}_3$ and show that the unusually broad Raman line shape has the form expected for an overdamped vibrational mode. From a detailed line-shape analysis we obtain the undamped mode frequency and the damping constant of this soft mode.