High speed two input real-time optical correlation using photorefractive BSO

Two input real-time optical correlation using photorefractive media is discussed. Consideration is given to the bearing of the input arrangement on the correlator's response time to changes in input. It is demonstrated that previous correlator arrangements using photorefractive Bi₁₂SiO₂₀ (BSO) may be adapted to improve their time response characteristics. Re-allocation of information carrying inputs leads to a two input correlator in which one input may be updated with arbitrary rapidity. The updating of the remaining input is subject to the limits imposed by the dynamics of the photorefractive effect. This is contrasted with previous correlator designs in which the updating of both inputs is subject to such dynamic limitations.     

Instantaneous profiles and turbulence statistics of supersonic free shear layers by Raman excitation plus laser-induced electronic fluorescence (Relief) velocity tagging of oxygen

A new method of flow tagging based on the vibrational excitation of oxygen is applied to both supersonic and high-speed subsonic air flows to generate instantaneous velocity profiles and turbulence statistics across the free shear layer. By simultaneously tagging two lines, both transverse and streamwise velocity correlations are found. Rayleigh scattering can also be imaged, so this flow diagnostic technique has the capability of instantaneously recording density cross sections and velocity profiles. A version of this paper was presented at the 11th Symposium on Turbulence, University of Missouri-Rolla, Oct. 17–19, 1988     

Dilute acid hydrolysis of softwoods

Whole tree chips obtained from softwood forest thinnings were converted to ethanol via a two-stage dilute acid hydrolysis followed by yeast fermentation. The chips were first impregnated with dilute sulfuric acid, then pretreated in a steam explosion reactor to hydrolyze, more than 90% of the hemicellulose and approx 10% of the cellulose. The hydrolysate was filtered and washed with water to recover the sugars. The washed fibers were then subjected to a second acid im pregnation and hydrolysis to hydrolyze as much as 45% of the reamining cellulose. The liquors from both hydrolysates were combined and fermented to ethanol by a Saccharomyces cerevisiae yeast that had been adapted to the inhibitors. Based on available hexose sugars, ethanol yields varied from 74 to 89% of theoretical. Oligosaccharide contents higher than about 10% of the total available sugar appear to have a negative impact on ethanol yield.     

A fluid‐fluid interaction method using decoupled subproblems and differing time steps

A time stepping procedure is proposed for a coupled fluid model motivated by the dynamic core of the atmosphere‐ocean system. The method exploits properties of the atmosphere‐ocean system to obtain efficiency. The momentum equations for the two fluids may be solved in parallel with different time step sizes. Stability is maintained with large time steps via a balanced two‐way passing of momentum flux. Numerical tests are provided that demonstrate the efficiency of the method. Published 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2012     

Coupling Considerations for Fabrication of Acoustooptic Tunable Filter

Induced acoustic wave to bare fiber through various types of horn are examined. The center wavelength and extinction ratio of the notch filter are dynamically tunable and dependent on the RF signals.     

Effect of viscous dissipation on the mixed convection heat transfer from an exponentially stretching surface

The mixed convection flow and heat transfer from an exponentially stretching vertical surface in a quiescent fluid is analyzed using similarity solution technique. Wall temperature and stretching velocity are assumed to have specific exponential function forms. The influence of buoyancy along with viscous dissipation on the convective transport in the boundary layer region is analyzed in both aiding and opposing flow situations. The flow is governed by the mixed convection parameter Gr/Re². The velocity and temperature inside the boundary layer are observed to be influenced by the parameters like Prandtl number Pr, Gebhart number Gb. Significant changes are observed in non-dimensional skin friction and heat transfer coefficients due to viscous dissipation in the medium. The flow and temperature distributions inside the boundary layer are analyzed and the results for non-dimensional skin friction and heat transfer coefficients are discussed through computer generated plots.     

Quantum Energy Levels and Classical Periodic Orbits: Discreteness and Statistical Duality

It is shown that both universal and non-universal correlations must exist between classical periodic orbits in order that Gutzwiller's semiclassical trace formula is consistent with a real, discrete quantum energy spectrum. Formulae for the two-point correlations are derived. The universal correlations are consistent with those conjectured by Argaman et al. (1993). Likewise, both universal and non-universal correlations must exist between quantum energy levels in order that the trace formula be consistent with the fact that periodic orbit actions are real and discrete. In this case, the two-point correlations implied are consistent with random matrix theory and previous semiclassical calculations. These ideas are illustrated with reference to the primes and the Riemann zeros.     

Azimuthal anisotropy of π⁰ production in Au+Au collisions at sqrt((s)NN)=200 GeV: path-length dependence of jet quenching and the role of initial geometry

We have measured the azimuthal anisotropy of π? production for 1相似文献   

Automorphism of orthogonal groups in characteristic 2

Let V be a nondefective quadratic space over a field F of characteristic 2. Assume that V has dimension at least ten and that F has more than two elements. Let Δ be one of the groups O(V), O⁺(V), O′(V), or $\text{Ω(V)}$ (the full orthogonal group, the rotation group, the spinorial kernel, or the commutator subgroup of O(V), respectively). Then Λ is an automorphism of Λ if and only if Λ(σ) = gσg^?1 for all σ in Δ where g is a semilinear automorphism of V that preserves the quadratic structure of V in the sense that Q(gx) = αQ(x)^u for all x in V where Q is the quadratic form, α is some nonzero element of F, and u is the field automorphism of F associated to g.     

On coupled-wave theory of two-beam self-diffraction

Coupled-wave equations are derived, which describe, in the geometrical-optics limit, the interaction between two beams in a medium having intensity dependent permittivity. These equations are interpreted physically and a solution is presented for the special case of non-uniform plane waves. New results on energy exchange and beam profile distortion are obtained and are contrasted with known results for static grating.