Compressed food components to minimize storage space

Compressed food products to minimize storage space for military application

Stability and error analysis of a splitting method using Robin–Robin coupling applied to a fluid–structure interaction problem

We analyze a splitting method for a canonical fluid structure interaction problem. The splittling method uses a Robin-Robin boundary condition, explicit strategy. We prove the method is stable and, furthermore, we provide an error estimate that shows the error at the final time T is O( √ T ∆t) where ∆t is the time step

Transport properties in the d-density wave state: Wiedemann-Franz law

We study the Wiedemann-Franz (WF) law in the d-density wave (DDW) model. Even though the opening of the DDW gap $(W_{0})$ profoundly modifies the electronic density of states and makes it dependent on energy, the value of the WF ratio at zero temperature (T=0) remains unchanged. However, neither electrical nor thermal conductivity display universal behavior. For finite temperature, with T greater than the value of the impurity scattering rate at zero frequency $\gamma(0)$ i.e. $\gamma(0)<T\ll W_{0}$, the usual WF ratio is obtained only in the weak scattering limit. For strong scattering there are large violations of the WF law.Comment: 1 figur

Effects of an in-plane magnetic field on c-axis sum rule and superfluid density in high-TcT_{c} cuprates

In layered cuprates, the application of an in-plane magnetic field $({\bf H})$ changes the c-axis optical sum rule and superfluid density $\rho_{s}$. For pure incoherent c-axis coupling, ${\bf H}$ has no effect on either quantities but it does if an additional coherent component is present. For the coherent contribution, different characteristic variations on ${\bf H}$ and on temperature result from the constant part $(t_{\perp})$ of the hopping matrix element and from the part $(t_{\phi})$ which has zero on the diagonal of the Brillouin zone. Only the constant part $(t_{\perp})$ leads to a dependence on the direction of ${\bf H}$ as well as on its magnitude.Comment: 3 figure

Observation of Apparently Zero-Conductance States in Corbino Samples

Using Corbino samples we have observed oscillatory conductance in a high-mobility two-dimensional electron system subjected to crossed microwave and magnetic fields. On the strongest of the oscillation minima the conductance is found to be vanishingly small, possibly indicating an insulating state associated with these minima.Comment: 4 pages, 3 figures, RevTex

Doping dependence of superconducting gap in YBa_2Cu_3O_y from universal heat transport

Thermal transport in the T -> 0 limit was measured as a function of doping in high-quality single crystals of the cuprate superconductor YBa_2Cu_3O_y. The residual linear term kappa_0/T is found to decrease as one moves from the overdoped regime towards the Mott insulator region of the phase diagram. The doping dependence of the low-energy quasiparticle gap extracted from kappa_0/T is seen to scale closely with that of the pseudogap, arguing against a non-superconducting origin for the pseudogap. The presence of a linear term for all dopings is evidence against the existence of a quantum phase transition to an order parameter with a complex (ix) component.Comment: 2 pages, 2 figures, submitted to M2S-Rio 2003 Proceeding

Bound Magnetic Polaron Interactions in Insulating Doped Diluted Magnetic Semiconductors

The magnetic behavior of insulating doped diluted magnetic semiconductors (DMS) is characterized by the interaction of large collective spins known as bound magnetic polarons. Experimental measurements of the susceptibility of these materials have suggested that the polaron-polaron interaction is ferromagnetic, in contrast to the antiferromagnetic carrier-carrier interactions that are characteristic of nonmagnetic semiconductors. To explain this behavior, a model has been developed in which polarons interact via both the standard direct carrier-carrier exchange interaction (due to virtual carrier hopping) and an indirect carrier-ion-carrier exchange interaction (due to the interactions of polarons with magnetic ions in an interstitial region). Using a variational procedure, the optimal values of the model parameters were determined as a function of temperature. At temperatures of interest, the parameters describing polaron-polaron interactions were found to be nearly temperature-independent. For reasonable values of these constant parameters, we find that indirect ferromagnetic interactions can dominate the direct antiferromagnetic interactions and cause the polarons to align. This result supports the experimental evidence for ferromagnetism in insulating doped DMS.Comment: 11 pages, 7 figure

Finite Temperature Time-Dependent Effective Theory for the Phase Field in two-dimensional d-wave Neutral Superconductor

We derive finite temperature time-dependent effective actions for the phase of the pairing field, which are appropriate for a 2D electron system with both non-retarded d- and s-wave attraction. As for s-wave pairing the d-wave effective action contains terms with Landau damping, but their structure appears to be different from the s-wave case due to the fact that the Landau damping is determined by the quasiparticle group velocity v_{g}, which for d-wave pairing does not have the same direction as the non-interacting Fermi velocity v_{F}. We show that for d-wave pairing the Landau term has a linear low temperature dependence and in contrast to the s-wave case are important for all finite temperatures. A possible experimental observation of the phase excitations is discussed.Comment: 23 pages, RevTeX4, 10 EPS figures; final version to appear in PR

Radiation induced oscillatory Hall effect in high mobility GaAs/AlGaAs devices

We examine the radiation induced modification of the Hall effect in high mobility GaAs/AlGaAs devices that exhibit vanishing resistance under microwave excitation. The modification in the Hall effect upon irradiation is characterized by (a) a small reduction in the slope of the Hall resistance curve with respect to the dark value, (b) a periodic reduction in the magnitude of the Hall resistance, $R_{xy}$, that correlates with an increase in the diagonal resistance, $R_{xx}$, and (c) a Hall resistance correction that disappears as the diagonal resistance vanishes.Comment: 4 pages text, 4 color figure