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Now showing items 1-10 of 12

#### the semiclassical limit of quantum dynamics. I. time evolution

(AIP Publishing, 1988-02)

The ℏ→0 limit of the quantum dynamics determined by the Hamiltonian H(ℏ) =−(ℏ2/2m)Δ+V on L 2(R n ) is studied for a large class of potentials. By convolving with certain Gaussian states, classically determined asymptotic ...

#### The thin-layer effect and interfacial stability in a two-layer Couette flow with similar liquids

(AIP Publishing, 1987-06)

The linear stability of Couette flow composed of two layers of immiscible fluids, one lying on top of the other, is considered for the special case when the two fluids have similar mechanical properties. The interfacial ...

#### viscosity and density stratification in vertical Poiseuille flow

(AIP Publishing, 1987-06)

The linear stability of plane three_layer vertical Poiseuille flow is considered. The layers are composed of two immiscible fluids, one next to the walls and one centrally located. The fluids have different viscosities and ...

#### 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 ...

#### spectral properties of the Kronig-Penney Hamiltonian with a localized impurity

(AIP Publishing, 1989-06)

It is shown that there exist bound states of the operator H ±λ=−(d 2/d x 2) +∑ m∈Z δ(⋅−(2m+1)π)±λW, W being an L 1(−∞,+∞) non‐negative function, in every sufficiently far gap of the spectrum of H 0=−d 2/d x 2 +∑ m∈Z ...

#### analytical solutions of model equations for two phase gas mixtures: Transverse velocity perturbations

(AIP Publishing, 1984)

Model equations for a dilute binary gas system are derived, using a linear BGK scheme. Complete analytical solutions for the stationary half_space problem are obtained for transverse velocity perturbations. The method of ...

#### analytic theory for the selection of a two-dimensional needle crystal at arbitrary Péclet number

(American Physical Society, 1989-10)

An accurate analytic theory is presented for the velocity selection of a two-dimensional needle crystal for arbitrary Péclet number for small values of the surface-tension parameter. The velocity selection is caused by the ...

#### exact behavior of Jost functions at low-energy

(AIP Publishing, 1988-01)

For Schrödinger operators with central potential q(r) and angular momentuml, the behavior of the Jost function F l (k) as k→0 is investigated. It is assumed that ∫∞ 0 d r (1+r)σ‖q(r)‖<∞, where σ≥1. Situations where q is ...

#### the effect of nonzero viscosity ratio on the stability of fingers and bubbles in a Hele-Shaw cell

(AIP Publishing, 1988-11)

The linear stability of a steadily moving bubble or a finger in a Hele–Shaw cell is considered in the case when gravity and the ratio between the viscosities of the less and more viscous fluids are nonzero. The effect of ...

#### location of essential spectrum of intermediate Hamiltonians restricted to symmetry subspaces

(AIP Publishing, 1988-10)

A theorem is presented on the location of the essential spectrum of certain intermediate Hamiltonians used to construct lower bounds to bound‐state energies of multiparticle atomic and molecular systems. This result is an ...