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Now showing items 1-10 of 86

#### Resonant Raman-active acoustic phonons in ion-implanted GaAs

(American Physical Society, 1988-09)

We have observed a new, strong feature at 47 cm-1 in the first-order Raman spectrum of ion-implanted GaAs, prior to any anneal. It is not present in the Raman spectrum of either amorphous or single-crystal GaAs. The peak ...

#### Crossover of interfacial dynamics

(American Physical Society, 1987-09)

Some dynamical models in which there is a significant interplay between interfacial and bulk degrees of freedom are treated at the mean-field (or Van Hove) level from a coarse-grained microscopic viewpoint. Specifically, ...

#### Spectral momentum density of graphite from (e,2e) spectroscopy: Comparison with first-principles calculation

(American Physical Society, 1988-03)

We have measured the spectral momentum density ρ(E,q) of graphite by (e,2e) spectroscopy for momentum parallel and perpendicular to the crystal c axis. In the independent-electron approximation, ρ(E,q)=ΣG‖Uk(G)‖2 ...

#### Pulse propagation in a randomly perturbed ocean: Single pulse statistics

(Acoustical Society of America, 1980-10)

A statistical theory of broadband single pulse propagation in a random ocean is presented. The mutual coherence function of the received signal is derived using an analysis based upon coupled mode theory. As propagation ...

#### The effect of surface tension on the shape of a Hele-Shaw cell bubble

(AIP Publishing, 1986-11)

Numerical and asymptotic solutions are found for the steady motion of a symmetrical bubble through a parallel‐sided channel in a Hele–Shaw cell containing a viscous liquid. The degeneracy of the Taylor–Saffman zero ...

#### Plant-soil processes in eriophorum vaginatum tussock tundra in alaska: a systems modeling approach

(Ecological Society of America, 1984)

The Arctic Tundra Simulator (ARTUS) is a computer-based simulation model of Eriophorum vaginatum tussock tundra ecosystems found in north central Alaska. ARTUS simulates the annual patterns of heat and water balance, carbon ...

#### 1/N expansion for the degenerate Anderson model in the mixed-valence regime

(American Physical Society, 1983-07)

The 1N expansion method for the degenerate Anderson model is formulated. N is the degeneracy factor of one of the f-electron configurations. Various ground-state properties are calculated. Excellent agreement with the ...

#### Frequency-wave number array processing

(Acoustical Society of America, 1981-03)

Most array signal processing systems use delay-and-sum beamforming to estimate source bearings. This paper demonstrates the close relationship between beamforming and frequency-wavenumber spectrum analysis. The latter ...

#### Analytic approximation to the ground-state energy of the Anderson model

(American Physical Society, 1988-09)

Using the nonperturbative Lanczos recursion scheme an analytic approximation to the ground-state energy of the single-impurity Anderson model is obtained. Calculations are carried out to a 5x5 matrix truncation. Comparisons ...

#### Fabry-Perot filters used for optical preprocessing

(Optical Society of America, 1981-10)

A Fabry-Perot etalon placed in the object plane of a coherent optical processing system can be used as a variable bandpass preprocessing filter. Use of this filter leads to improved correlation signals in a matched spatial ...