814 research outputs found

    Paramagnetic anisotropic magnetoresistance in thin films of SrRuO3

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    SrRuO3 is an itinerant ferromagnet and in its thin film form when grown on miscut SrTiO3 it has Tc of ~ 150 K and strong uniaxial anisotropy. We measured both the Hall effect and the magnetoresistance (MR) of the films as a function of the angle between the applied field and the normal to the films at temperatures above Tc. We extracted the extraordinary Hall effect that is proportional to the perpendicular component of the magnetization and thus the MR for each angle of the applied field could be correlated with the magnitude and orientation of the induced magnetization. We successfully fit the MR data with a second order magnetization expansion, which indicates large anisotropic MR in the paramagnetic state. The extremum values of resistivity are not obtained for currents parallel or perpendicular to the magnetization, probably due to the crystal symmetry.Comment: 3 pages, 3 figure

    Comparison of spray-dried blood meal and fish by-products in the phase II starter pig diet

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    A total of 311 weanling pigs (initially 10.9 lb and 17 d of age) was used to compare fish by-products, spray-dried blood meal and combinations of spray-dried blood meal and fish by-products in the phase II (d 7 to 25) diet. Pigs were allotted by weight to one of five experimental treatments with 8 to 11 pigs/pen and seven replications. Pigs were placed on a common phase I diet (d 0 to 7 postweaning) that contained 7.5%spray-dried porcine plasma, 1.75% spray-dried blood meal, and 20% dried whey. The phase I diet was formulated to contain 1.5% lysine, .9% Ca, and .8% P. Pigs were then randomly assigned to one of five dietary treatments. All phase II diets (d 7 to 25 postweaning) contained 10% dried whey and were formulated to contain 1.25% lysine and .36% methionine. The control diet contained 2.5% spray-dried blood meal (SDBM) and 10% dried whey. Select menhaden fish meal (SMFM) and spray-dried fish hydrolysate (SDFH) replaced SDBM on an equal lysine basis at 5% and 4.8%, respectively, and 2.5% SMFM + 1.25% SDBM and 2.0% SDFH + 1.25% SDBM were used in combinations to form the other four dietary treatments. Average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (F/G) were improved with the addition of SDBM in the fIrst week (d 7 to 14) of phase II. No differences were observed in ADG and ADFI for the overall phase II period. Pigs fed SDBM had poorer FIG (d 7 to 25) compared to pigs fed either SMFM or SDFH. However, SDBM was the most cost effective protein source in this experiment.; Swine Day, Manhattan, KS, November 19, 199

    A combination of spray-dided porcine plasma and spray-dried blood meal optimizes starter pig performance

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    A total of 298 weanling pigs (initially 12.11b and 19 d of age) was used in a 25-\u3c1 growth trial to examine the influence of various combinations of spray-dried porcine plasma (SDPP) and spray-dried blood meal (SDBM) in a high nutrient density diet on starter pig performance. Pigs were allotted by weight to eight replicates of five treatments with seven to eight pigs per pen. Pigs were assigned to one of five dietary treatments with 0, 25, 50, 75, or 100% of the SDPP replaced with SDBM on an equal lysine basis. Therefore, diets contained 10, 7.5,5.0, 2.5, or 0% SDPP combined with 0, 1.63, 3.25, 4.8, or 6.5% SDBM, respectively. All phase I diets were formulated to contain 20% dried whey, 1.50% lysine, .81% isoleucine, and .37% methionine. These diets were fed from d 0 to 14 postweaning. On d 14, all pigs were switched to a common phase II diet containing 10% dried whey and 2.5% SDBM and was formulated to 1.25% lysine. Pigs were fed this diet for the remainder of the trial (d 14 to 25 postweaning). A quadratic response occurred for average daily gain and feed efficiency during phase I, with pigs fed a combination of spray-dried porcine plasma and spray-dried blood meal having superior performance compared to pigs fed diets containing only spray-dried plasma or spray-dried blood. Maximum performance was seen with the combination of 7.5% spray-dried porcine plasma and 1.63% spray-dried blood meal. Therefore, the results of this trial show that phase I diet cost can be reduced and performance improved by formulating the diet with a combination of spray-dried porcine plasma and spray-dried blood meal rather than spray-dried plasma alone.; Swine Day, Manhattan, KS, November 19, 199

    Comment on "Effects of spatial dispersion on electromagnetic surface modes and on modes associated with a gap between two half spaces"

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    Recently Bo E. Sernelius [Phys. Rev. B {\bf 71}, 235114 (2005)] investigated the effects of spatial dispersion on the thermal Casimir force between two metal half spaces. He claims that incorporating spatial dispersion results in a negligible contribution from the transverse electric mode at zero frequency as compared to the transverse magnetic mode. We demonstrate that this conclusion is not reliable because, when applied to the Casimir effect, the approximate description of spatial dispersion used is unjustified.Comment: 9 pages, minor corrections in accordance with the journal publication have been mad

    Title Stabilization of Membrane Pores by Packing

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    We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks tending to re-seal or grows without bound til to membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a multipore membrane system, the distribution of pore size and associated pore lifetime are calculated within the mean field approximation. We predict that, above certain temperature when the effective line tension becomes negative, the membrane exhibits a dynamic sieve-like porous structure.Comment: 4 pages, 4 figure

    Quasi-long-range order in nematics confined in random porous media

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    We study the effect of random porous matrices on the ordering in nematic liquid crystals. The randomness destroys orientational lang-range order and drives the liquid crystal into a glass state. We predict two glass phases one of which possesses quasi-long-range order. In this state the correlation length is infinite and the correlation function of the order parameter obeys a power dependence on the distance. The small-angle light-scattering amplitude diverges but slower than in the bulk nematic. In the uniaxially strained porous matrices two new phases emerge. One type of strain induces an anisotropic quasi-long-range-ordered state while the other stabilizes nematic long-range order.Comment: 4 pages, Revte

    Accretion Disk Instabilities, CDM models and their role in Quasar Evolution

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    We have developed a consistent analytical model to describe the observed evolution of the quasar luminosity function. Our model combines black hole mass distributions based on the Press - Schechter theory of the structure formation in the Universe with quasar luminosity functions resulting from a physics-based emission model that takes into account the time-dependent phenomena occurring in the accretion disks. Quasar evolution and CDM models are mutually constraining, therefore our model gives an estimation of the exponent, n, of the power spectrum, P(k), which is found to be -1.8 < n < -1.6. We were able to reject a generally assumed hypothesis of a constant ratio between Dark Matter Halo and the Black Hole mass, since the observed data could not be fitted under this assumption. We found that the relation between the Dark Matter Halos and Black Hole masses is better described by M_{BH}=M_{DMH}^{0.668}. This model provides a reasonable fit to the observed quasar luminosity function at redshifts higher than ~2.0. We suggest that the disagreement at lower redshift is due to mergers. Based on the agreement at high redshift, we estimated the merger rate at lower redshift, and argue that this rate should depend on the redshift, like (1+z)^3.Comment: 15 pages, 18 figures, Accepted for Publication in Ap

    Polarization conversion spectroscopy of hybrid modes

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    Enhanced polarization conversion in reflection for the Otto and Kretschmann configurations is introduced as a new method for hybrid-mode spectroscopy. Polarization conversion in reflection appears when hybrid-modes are excited in a guiding structure composed of at least one anisotropic media. In contrast to a dark dip, in this case modes are associated to a peak in the converted reflectance spectrum, increasing the detection sensitivity and avoiding confusion with reflection dips associated with other processes as can be transmission.Comment: 4 pages, 4 figure

    Dynamic Fluctuation Phenomena in Double Membrane Films

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    Dynamics of double membrane films is investigated in the long-wavelength limit including the overdamped squeezing mode. We demonstrate that thermal fluctuations essentially modify the character of the mode due to its nonlinear coupling to the transversal shear hydrodynamic mode. The corresponding Green function acquires as a function of the frequency a cut along the imaginary semi-axis. Fluctuations lead to increasing the attenuation of the squeezing mode it becomes larger than the `bare' value.Comment: 7 pages, Revte

    Sound modes broadening for Fibonacci one dimensional quasicrystals

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    We investigate vibrational excitation broadening in one dimensional Fibonacci model of quasicrystals (QCs). The chain is constructed from particles with two masses following the Fibonacci inflation rule. The eigenmode spectrum depends crucially on the mass ratio. We calculate the eigenstates and eigenfunctions. All calculations performed self-consistently within the regular expansion over the three wave coupling constant. The approach can be extended to three dimensional systems. We find that in the intermediate range of mode coupling constants, three-wave broadening for the both types of systems (1D Fibonacci and 3D QCs) depends universally on frequency. Our general qualitative conclusion is that for a system with a non-simple elementary cell phonon spectrum broadening is always larger than for a system with a primitive cell (provided all other characteristics are the same).Comment: 2o pages, 15 figure
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