Transportation of thermalized primary recoil ions from nuclear reactions by helium flow has been investigated as a means of injecting short-lived radioactive nuclides into an on-line isotope separator. Several short-lived radioactive isotopes of highly nonvolatile elements such as B, Sc, Nb, and W have been separated. The efficiency for heavy nuclides with half-lives above 1 ms is between 1 and 10%. The shortest-lived activity identified in an on-line separation is the 182-μs isomeric state in ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$.

The fast-atom-laser collinear beams technique has been used to measure the relativistic Doppler effect to an accuracy comparable to the best previous experiments (5 parts in ${10}^3$). Improved calibration data and a similar technique, but employing two lasers, is proposed, which should improve the test of time dilatation by at least another factor of 10.

A differential equation is proposed to describe the evolution of a screw dislocation in a continuous medium under an externally applied displacement field. The derivation is based on the conservation of energy and momentum and the neglect of radiation reaction and renormalizability: The equation of motion must be such that it allows for a renormalization of the infinite self-energy and momentum of the infinitely thin dislocation. The extent to which the result might hold for general dislocation loops is discussed.

Measurements of the ratio $R$ of the purely leptonic weak neutral-current cross sections $\frac{\sigma ({\nu }_{\mu }e\to {\nu }_{\mu }e)}{\sigma ({\overline{\nu }}_{\mu }e\to {\overline{\nu }}_{\mu }e)}$ and of the absolute value of $\sigma ({\overline{\nu }}_{\mu }e\to {\overline{\nu }}_{\mu }e)$ are reported. These yield $R={1.38}_{-0.31\mathrm{}}^{+0.40\mathrm{}}\left(\mathrm{stat}\right)\pm 0.17\left(\mathrm{syst}\right)$ and $\frac{\sigma ({\overline{\nu }}_{\mu }e\to {\overline{\nu }}_{\mu }e)}{E_{{\overline{\nu }}_{\mu }}}=[1.16\mathrm{}\pm 0.20(\mathrm{stat})\pm 0.14(\mathrm{syst}\left)\right]\times {10}^{-42\mathrm{}}$ ${\mathrm{cm}}^2$/GeV. This value of $R$ determines the fundamental weak neutral-current parameter to be ${{sin}^2\theta }_W=0.209\mathrm{}\pm 0.029\left(\mathrm{stat}\right)\pm 0.013\left(\mathrm{syst}\right)$.

Lower limits in the range of ${10}^{31}$ to ${10}^{32}$ yr for the partial lifetimes of a number of nucleon decay modes are obtained from a 204-live-day exposure in an 8-ktonne water Cherenkov detector (3.3 ktonne in the fiducial volume). During this period 169 contained events were observed at a rate and with characteristics consistent with expected backgrounds from atomospheric $\nu$ interactions. Nine of the contained events are compatible with either a $\nu$ interaction or nucleon decay into a number of non-$\nu$ modes.

The relative phase of the longitudinal and transverse form factors of the 4.439-MeV $J^{\pi }=2^{+}$ state of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ has been measured at $q_{\mathrm{eff}}=0.36\mathrm{} \mathrm{and} 0.46$ ${\mathrm{fm}}^{-1\mathrm{}}$. This phase was found to be negative, of the same sign given by Siegert's theorem in the long-wavelength limit. This measurement represents the first nuclear structure result derived through the ($e, e^{\prime }\gamma$) reaction.

We performed an experiment to investigate the anomalous mean-free-path phenomenon for projectile fragments of ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$. 1846 charge-changing collisions of fragments with charges $Z=20-25\mathrm{}$ were analyzed with plastic nuclear track detectors. We observed no evidence for anomalous fragments.

We introduce a model which accounts for surface-generated dynamical fluctuations, and we evaluate the corresponding absorption and resonance fluorescence spectra. Our results provide the first semiquantitative agreement with a recent experiment.

Important axial magnetic fields can grow up through the dynamo effect in laser-matter interactions. The growth rate of these fields is calculated for an isothermal plasma. Faraday rotation on the backscattered emission shows that axial fields in the megagauss range are present in a laser-produced plasma.

We present results from an analysis of the ion cyclotron range of frequencies (ICRF) wave interactions with flute-interchange modes. The analysis is valid for an arbitrary wave vector of the ICRF waves, and shows that these modes can be stabilized by ICRF sideband coupling to them. The modes can be stabilized in a variety of ways, depending on details of the ICRF wave structure. We also find a new rf-driven fluid instability for a range of parallel (to the magnetic field) rf wavelengths.

The critical phenomena of a microemulsion system were studied by applied external pressure for the first time. The divergence of the scattering intensity and the static correlation length as functions of $\Delta P\equiv |P-P_c|$ are described by the critical exponents $\gamma$ and $\nu$, respectively. The critical exponents $\nu$ and $\gamma$ associated with $\Delta P$ are the same as those obtained with other thermodynamic variables such as temperature and oil alkane carbon number.

We report measurements of the osmotic susceptibility and correlation length for the pseudobinary mixture of guaiacol ($o$-methoxy phenol) plus glycerol-water as a function of temperature and water content $x[x\equiv \mathrm{weight}\mathrm{of}\mathrm{water}/(\mathrm{weight}\mathrm{of}\mathrm{water}\mathrm{plus}\mathrm{weight}\mathrm{of}\mathrm{glycerol}\left)\right]$. This system exhibits a limited two-phase region which vanishes for $x<\mathrm{}{x}_0\simeq 0.0137$. We observed a smooth transition from nearly Ising-type behavior for $x\gtrsim 4x_0$ through a non-power-law regime to doubled exponents for $x\simeq x_0$ and saturating divergences with doubled exponents for $x<\mathrm{}{x}_0$.

Whether quantum mechanical systems, within the interval between two measurements, can be assigned definite, simultaneous values of noncommuting observables has been the subject of a very old dispute. A certain widely held assumption about such systems has been crucial to that dispute. That assumption turns out to be wrong: A previously unknown prediction of quantum mechanics, which fails to satisfy that assumption, is described here, and the consequences of that failure are considered.

We propose and analyze a simple model for the surface of an imperfect crystal in equilibrium with its vapor, below the roughening transition. We show that this system exhibits typical glassy behavior and opens the exciting possibility of experimentally testing recent theoretical ideas originating in spin-glasses.

A numerical simulation of a concentrated polymer system is presented. The dynamics used are those of the primitive chain model of Doi and Edwards with excluded volume, known as "reptation dynamics." It is found that the time-dependent correlation functions with excluded volume relax more slowly than in the case of no excluded volume. From the power-law dependence of these correlation functions on time, an estimate of the relaxation time for this system is obtained as a function of molecular weight $M$. This implies that the viscosity should be proportional to $M^{3.25\pm 0.1}$.

An electron phase shift down to an order of $\frac{\lambda }{100}$ ($\lambda$ is wavelength) was detected for the first time. This was realized by applying longitudinally reversed shearing interferometry in the optical reconstruction stage of electron holography. Thickness changes due to monatomic steps in Mo${\mathrm{S}}_2$ films were clearly observed in phase-amplified interference micrographs.

Optical second-harmonic generation has been applied to the study of clean Si(111) 2×1 and 7×7 surfaces. By an analysis of polarization dependences of the two reconstructions, the symmetry properties of the surfaces have been determined. The 2×1 to 7×7 surface phase transformation during thermal annealing has also been monitored in real time by the second-harmonic technique.

The local-density scheme is used to calculate the self-consistent electron density of a semi-infinite metal in the presence of a static external field of finite wave vector ${\mathbf{q}}_{\mathrm{\parallel }}$. The total electrostatic potential is used to determine the rate of exciting electron-hole pairs at low frequencies. The lifetime of the CO stretch vibration on Cu is calculated and the intensity of inelastically scattered electrons is predicted for finite momentum transfers.

The authors report ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ NMR studies of ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$O adsorbed on small Pt particles and show that the data yield quantitative information about the CO-Pt bond. They find that the ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ resonance position is shifted 200 ppm to higher frequency than in CO gas. They prove that the shift arises from polarization of the electron spins in the bond (a Knight shift) by showing that the spin-lattice relaxation obeys the Korringa law. Using ESR results from CO radicals, they deduce the local density of states of the CO $5\sigma$ orbital on the carbon atom at the Fermi energy. The NMR also reveals diffusion of CO on the Pt surface.

Resonant Raman scattering is used to quantify the effect of disorder and extrinsic order on Peierls systems such as ${\left(\mathrm{CH}\right)}_x$. We introduce "$\tilde{\lambda }$ plots" in which the phonon and gap distribution are related and characterize the system by the functional dependence of the gap $2\Delta$ on the coupling $\tilde{\lambda }$. For cis-rich trans-${\left(\mathrm{CH}\right)}_x$ the disorder is extrinsic with energy ${\Delta }^p$ and $p=1\mathrm{}$. For all trans-${\left(\mathrm{CH}\right)}_x$ the $\tilde{\lambda }$ plot yields intrinsic disorder, i.e., variation in the $e-p$ coupling. cis-${\left(\mathrm{CH}\right)}_x$ is ordered with a 5% extrinsic gap of the full energy gap of 1.95 eV.