We report a new experimental NMR technique of wide applicability wherein the NMR of nuclei at crystalline sites near a localized paramagnetic impurity is directly observed. We find this method useful in determining electron-nuclear interactions and crystal structure, and as a site-selective probe of spin lattice relaxation, spin diffusion, and dynamic polarization processes for nuclei. We have applied this technique to Y${\left({\mathrm{C}}_2{\mathrm{H}}_5\mathrm{S}{\mathrm{O}}_4\right)}_3$·9${\mathrm{H}}_2$O doped with ${\mathrm{Yb}}^{3+}$ and ${\mathrm{Nd}}^{3+}$, Ca${\mathrm{F}}_2$:${\mathrm{Eu}}^{2+}$, and N${\mathrm{H}}_4$Cl:${\mathrm{Cu}}^{2+}$(2${\mathrm{H}}_2$O).

Recent inelastic neutron scattering observations on the bcc phase of solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ are interpreted as showing (i) substantial interference between the one-phonon peak and the multiphonon background, due to strong phonon interaction processes; and (ii) a Debye-Waller factor, extracted by use of first-moment sum rules, which closely resembles the structure of superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. We discuss implications of this resemblance for the ground-state wave functions of crystalline and superfluid helium.

We have measured the optical mixing spectrum of erythrocyte ghosts prepared in a manner that restores the ${\mathrm{Na}}^{+}$-${\mathrm{K}}^{+}$ active transport mechanism contained in the cell membrane. The homodyne spectrum contains an intense spectral line centered at about 170 Hz in addition to an expected line at 0 Hz. Evidence is presented which relates the shifted spectral component to the active transport process.

We have studied the plasma transport processes in the dc octopole with a toroidal magnetic field. The plasma diffusion is characterized by three principal collision-frequency regimes. The magnitude of the diffusion coefficient shows an inverse-square dependence on the magnetic field in all regimes. In the high-collision-frequency regime, the measured local diffusion coefficient agrees with Pfirsch-Schlüter diffusion in both rotational transform dependence and magnitude. Both for intermediate and low values of collision frequency, the enhancement of the decay rate agrees with neoclassical theory.

The polarized ($I_{\parallel }$) and depolarized ($I_{\perp }$) scattered light intensity by fluctuations of the order parameter $Q$ near the isotropic-nematic phase transition of para-methoxybenzylidene para-$n$-butylaniline has been measured as a function of the scattering angle over a range of temperatures above the phase-transition temperature $T_p$ by means of two different incident wavelengths. Our results are in excellent agreement with the phenomenological theory of de Gennes. We also find the elastic constants $L_1\gg L_2$ while $L_1$ depends upon temperature.

The sidebands which accompany a large-amplitude electron wave on a plasma column are shown to arise from selectively amplified noise; the amplification mechanism is a parametric coupling between the sideband frequencies and the oscillations of the electrons trapped in the large wave.

Measurements have been made within a few micrometers of a current-carrying superconducting-normal boundary, which indicate that an electric potential exists in the superconductor in this region. Near the transition temperature the experimental results are consistent in magnitude and temperature dependence with a theory recently proposed by Rieger, Scalapino, and Mercereau.

Reversible threshold switching in the amorphous covalent alloys is explained by the carrier transport and recombination properties of the "relaxation semiconductor," defined by dielectric relaxation time greater than recombination time. In these alloys, the recombination after single free paths pins the Fermi level at the location for minimum conductivity. Characteristic "recombinative injection" of minority electrons is the final process in the switching, and it accounts for observed behavior in its various aspects.

We have computed the surface-plasmon dispersion relation for a metal and compared it with experimental results for Al and Mg. The metal surface is approximated by a step potential and the calculation carried out within the quantum-mechanical random-phase approximation. The integral equation for the self-sustained oscillations is handled by a variational approach. Our dispersion relation is in much better agreement with experimental results than the relation computed for a semi-infinite electron gas.

We report measurements of a large, nearly discontinuous change in the superconducting transition temperature of Au${\mathrm{Ga}}_2$ near 6 kbar as predicted earlier from pressure measurements of cross-sectional areas of the Fermi surface. This is interpreted as strong evidence for a pressure-induced electron transition near 6 kbar at liquid-He temperatures.

Magnetophonon resonances in the hot-electron mobility have been observed in pure $n$-InSb at 77°K in transverse magnetic fields with the application of sufficiently small voltage to produce a slight change in the mobility. The minima in the quantity $\beta$ in the formula $\mu ={\mu }_0(1-\beta E^2)$ are attributed to resonant cooling of hot electrons due to optical-phonon-induced transitions between Landau levels.

Mössbauer studies show that cobalt ions in LaCo${\mathrm{O}}_3$ exist predominantly in the low-spin ${\mathrm{Co}}^{\mathrm{III}}$ state at low temperatures and partially transform to the high-spin ${\mathrm{Co}}^{3+}$ state up to 200 K. Above 200 K, ${\mathrm{Co}}^{\mathrm{II}}$ and ${\mathrm{Co}}^{4+}$ ions are formed by the transfer of $d$ electrons from ${\mathrm{Co}}^{3+}$ to ${\mathrm{Co}}^{\mathrm{III}}$; ${\mathrm{Co}}^{3+}$ ions completely disappear at the first-order localized-to-itinerant electron transition temperature.

We have investigated the effect of hydrostatic pressure on chromium-rich iron alloys with Ru and Mn additions. The results show that addition of Fe to Cr rotates the commensurate-incommensurate phase boundary and causes the reversal in the ordering sequence of the magnetic transitions observed in Cr-Fe alloys. Many other anomalous characteristics of Cr-Fe alloys are explained.

Measurements of cross sections and analyzing powers have been made for the inelastic scattering of 24.5-MeV polarized protons leading to the lowest $0^{+}$, $2^{+}$, and $4^{+}$ states in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$. The results for both ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ are best reproduced when the full Thomas form of the deformed, spin-dependent optical potential is employed in a coupled-channel calculation. In contrast to ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$, the results for ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ indicate that only a small hexadecapole deformation is needed to reproduce both the cross sections and the analyzing powers for the ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ ground-state rotational band.

The recent precise measurements of $\pi -N$ scattering in the 3-3 energy range have been fitted by Rittenberg et al., using four different phenomenological resonance formulas. These fits yield masses in the range 1234 to 1231 MeV, with widths ranging from 112 to 120 MeV. We show that these fits, as well as an $N{D}^{-1\mathrm{}}$ fit, all yield a nearly unique value for the position of the 3-3 pole in the $S$ matrix at $1211-50i$ MeV.

We discuss a summability mechanism which preserves nonlinear perturbative conditions such as unitarity of the Feynman series. This condition, which relates a function $f\left(z\right)\mathrm{}$ and a series $\Sigma a_n{z}^n$ by the requirement $\mathrm{}\left|f\right(z)-\Sigma \stackrel{N}{n=0\mathrm{}}{a}_n{z}^n|<~A{\sigma }^{N+1\mathrm{}}\mathrm{}(N+1\mathrm{})!{\mathrm{}\left|z\right|\mathrm{}}^{N+1\mathrm{}}$ is applicable to certain divergent series.

We report measured asymmetries as a function of polar scattering angle for the reactions $\overline{p}p\to {\pi }^{-}{\pi }^{+}$ and $\overline{p}p\to \overline{p}p$, using a polarized proton target. The annihilation data, obtained at a $\overline{p}$ momentum of 1.64 GeV/c, are the first asymmetry data to be collected for this channel. A fit of these data and published differential cross section data is made by a partial-wave expansion, and the results are compared with a previous analysis. The elastic scattering data, obtained at 1.64 and 2.55 GeV/c, are fitted with an eight-parameter strong-absorption model.

A phenomenological study is carried out for the production of heavy $\mu$-type leptons in one-particle inclusive neutrino reactions. The muon spectrum is found to be distorted in a significant fashion from that expected with no heavy-lepton production, and sensitive tests are presented which serve to signal the fleeting presence of such excited leptons.

We report measurements of hydrogen charge fractions following the collision of ${\mathrm{H}}^{-}$ on He. Incident energy is varied from 0.47 to 20 keV. The charge fractions were measured at scattering angles of 0.3° to 5°. A large neutral charge fraction is found at all energies and angles. At high energies, the elastic channel has a simple velocity dependence. We propose a simple model for this elastic channel.

The $K$-shell fluorescence yield ${\omega }_K$ for Be, B, and C was determined from intensity measurements of the $K$ emission bands excited in fluorescence with the synchrotron radiation of the 7.5-GeV DESY electron synchrotron. The following values for ${\omega }_K$ were obtained: beryllium, 3.6×${10}^{-4\mathrm{}}$; boron, 5.7×${10}^{-4\mathrm{}}$; carbon (graphite), 8.8×${10}^{-4\mathrm{}}$; the mean error being ±30%. These results and those of previous measurements are discussed.