Volume 67, Issue 21

P. Chowdhury, C. J. Lister, D. Vretenar, Ch. Winter, V. P. Janzen, H. R. Andrews, D. J. Blumenthal, B. Crowell, T. Drake, P. J. Ennis, A. Galindo-Uribarri, D. Horn, J. K. Johansson, A. Omar, S. Pilotte, D. Prévost, D. Radford, J. C. Waddington, and D. Ward

Phys. Rev. Lett. 67, 2950 (1991) - Published 18 November, 1991

Atomic, Molecular, and Optical Physics

Annihilation of positrons on organic molecules

T. J. Murphy and C. M. Surko

Phys. Rev. Lett. 67, 2954 (1991) - Published 18 November, 1991

Nonlinear Dynamics, Fluid Dynamics, Classical Optics, Etc.

Crossover length from invasion percolation to diffusion-limited aggregation in porous media

Julio F. Fernández, Rafael Rangel, and Juan Rivero

Phys. Rev. Lett. 67, 2958 (1991) - Published 18 November, 1991

Observation of coherent transition radiation

U. Happek, A. J. Sievers, and E. B. Blum

Phys. Rev. Lett. 67, 2962 (1991) - Published 18 November, 1991

Condensed Matter: Structure, Etc.

Experimental evidence for nonwetting with superfluid helium

P. J. Nacher and J. Dupont-Roc

Phys. Rev. Lett. 67, 2966 (1991) - Published 18 November, 1991

Nucleation of $C_{60}$ clusters

James R. Chelikowsky

Phys. Rev. Lett. 67, 2970 (1991) - Published 18 November, 1991

Vibrations of fractal drums

B. Sapoval, Th. Gobron, and A. Margolina

Phys. Rev. Lett. 67, 2974 (1991) - Published 18 November, 1991

Long-ranged surface perturbations for confined fluids

A. O. Parry, R. Evans, and D. B. Nicolaides

Phys. Rev. Lett. 67, 2978 (1991) - Published 18 November, 1991

Roughening transition observed on the prism facet of ice

Michael Elbaum

Phys. Rev. Lett. 67, 2982 (1991) - Published 18 November, 1991

Low-energy electron-microscopy investigations of orientational phase separation on vicinal Si(111) surfaces

R. J. Phaneuf, N. C. Bartelt, Ellen D. Williams, W. Świȩch, and E. Bauer

Phys. Rev. Lett. 67, 2986 (1991) - Published 18 November, 1991

Can clusters be superheated?

Jeremy Broughton

Phys. Rev. Lett. 67, 2990 (1991) - Published 18 November, 1991

Silicon cluster ions: Evidence for a structural transition

Martin F. Jarrold and Vladimir A. Constant

Phys. Rev. Lett. 67, 2994 (1991) - Published 18 November, 1991

High-pressure optical studies on sulfur to 121 GPa: Optical evidence for metallization

Huan Luo, Serge Desgreniers, Yogesh K. Vohra, and Arthur L. Ruoff

Phys. Rev. Lett. 67, 2998 (1991) - Published 18 November, 1991

Condensed Matter: Electronic Properties, Etc.

Orientation of $C_{60}$ clusters in solids

O. Gunnarsson, S. Satpathy, O. Jepsen, and O. K. Andersen

Phys. Rev. Lett. 67, 3002 (1991) - Published 18 November, 1991

Description of the trends for rare-earth impurities in semiconductors

C. Delerue and M. Lannoo

Phys. Rev. Lett. 67, 3006 (1991) - Published 18 November, 1991

Observation of persistent negative photoconductivity effect in AlGaAs/GaAs modulation-doped structures

A. L. Powell, C. C. Button, J. S. Roberts, P. I. Rockett, H. G. Grimmeiss, and H. Pettersson

Phys. Rev. Lett. 67, 3010 (1991) - Published 18 November, 1991

New nonlocal magnetoresistance effect at the crossover between the classical and quantum transport regimes

A. K. Geim, P. C. Main, P. H. Beton, P. Steda, L. Eaves, C. D. W. Wilkinson, and S. P. Beaumont

Phys. Rev. Lett. 67, 3014 (1991) - Published 18 November, 1991

Semiclassical solitons and the S=1/2 Heisenberg model

N. Theodorakopoulos and N. C. Bacalis

Phys. Rev. Lett. 67, 3018 (1991) - Published 18 November, 1991

Vortex dynamics in superconducting fractal networks

R. Meyer, J. L. Gavilano, B. Jeanneret, R. Théron, Ch. Leemann, H. Beck, and P. Martinoli

Phys. Rev. Lett. 67, 3022 (1991) - Published 18 November, 1991

Observation of pair currents in superconductor-semiconductor contacts

A. Kastalsky, A. W. Kleinsasser, L. H. Greene, R. Bhat, F. P. Milliken, and J. P. Harbison

Phys. Rev. Lett. 67, 3026 (1991) - Published 18 November, 1991

Combined single-electron and coherent-Cooper-pair tunneling in voltage-biased Josephson junctions

Alec Maassen van den Brink, Gerd Schön, and L. J. Geerligs

Phys. Rev. Lett. 67, 3030 (1991) - Published 18 November, 1991

Quantum tunneling currents in a superconducting junction

A. H. Worsham, N. G. Ugras, D. Winkler, D. E. Prober, N. R. Erickson, and P. F. Goldsmith

Phys. Rev. Lett. 67, 3034 (1991) - Published 18 November, 1991

Proximity effect in ${YBa}_{2}$ ${Cu}_{3}$ $O_{7}$ / $Y_{0.6}$ $\Pr_{0.4}$ ${Ba}_{2}$ ${Cu}_{3}$ $O_{7}$ / ${YBa}_{2}$ ${Cu}_{3}$ $O_{7}$ junctions

E. Polturak, G. Koren, D. Cohen, E. Aharoni, and G. Deutscher

Phys. Rev. Lett. 67, 3038 (1991) - Published 18 November, 1991

COMMENTS

Comment on ‘‘New dynamical equation for cracks’’

K. Sieradzki and Rong Li

Phys. Rev. Lett. 67, 3042 (1991) - Published 18 November, 1991

Marder replies

M. Marder

Phys. Rev. Lett. 67, 3043 (1991) - Published 18 November, 1991

Comment on ‘‘Theory of ideal metals’’

José M. Soler

Phys. Rev. Lett. 67, 3044 (1991) - Published 18 November, 1991

Shore and Rose reply

Herbert B. Shore and James H. Rose

Phys. Rev. Lett. 67, 3045 (1991) - Published 18 November, 1991