34,946 research outputs found

    A Unified Gravity-Electroweak Model Based on a Generalized Yang-Mills Framework

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    Gravitational and electroweak interactions can be unified in analogy with the unification in the Weinberg-Salam theory. The Yang-Mills framework is generalized to include space-time translational group T(4), whose generators T_{\mu}(=\p/\p x^{\mu}) do not have constant matrix representations. By gauging T(4)×SU(2)×U(1)T(4) \times SU(2) \times U(1) in flat space-time, we have a new tensor field ϕμν\phi_{\mu\nu} which universally couples to all particles and anti-particles with the same constant gg, which has the dimension of length. In this unified model, the T(4) gauge symmetry dictates that all wave equations of fermions, massive bosons and the photon in flat space-time reduce to a Hamilton-Jacobi equation with the same `effective Riemann metric tensor' in the geometric-optics limit. Consequently, the results are consistent with experiments. We demonstrated that the T(4) gravitational gauge field can be quantized in inertial frames.Comment: 12 pages. To be published in "Modern Physics Letters A

    Critical comments on the constancy of the speed of light

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    Criticisms on the theory of the constancy of the speed of light are answered. It is shown that the new theory is not logically inconsistent for the reasons expressed

    Effective interactions between star polymers

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    We study numerically the effective pair potential between star polymers with equal arm lengths and equal number ff of arms. The simulations were done for the soft core Domb-Joyce model on the simple cubic lattice, to minimize corrections to scaling and to allow for an unlimited number of arms. For the sampling, we used the pruned-enriched Rosenbluth method (PERM). We find that the potential is much less soft than claimed in previous papers, in particular for f≫1f\gg 1. While we verify the logarithmic divergence of V(r)V(r), with rr being the distance between the two cores, predicted by Witten and Pincus, we find for f>20f>20 that the Mayer function is hardly distinguishable from that for a Gaussian potential.Comment: 5 pages, 5 figure

    Speed of light as measured by two terrestrial stable clocks

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    Despite the recent criticism within the special theory of relativity, there exists an arrangement of stable clocks rotating with the earth which predicts diurnal variations of the one-way speed of light, as suggested previously

    SMALL-SCALE SAFETY TEST REPORT FOR RDX (SECOND CALIBRATION)

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    RDX was provided by Indian Head and was dried at 60 C for 16 hours, cooled and kept in a desiccator before use. Please note that the impact testing was done on both pellets and loose powder which resulted in different data. The impact sensitivity on pressed pellets was 34 cm that is greater than that on loose powder, as expected. The impact test data on the loose powder was similar to what Indian Head and LANL got. Remarkable consistent results were observed for test results of loose powder RDX. The average impact sensitivyt (DH{sub 50}) was 21.8 cm and the average friction sensitivity (F{sub 50}) for loose powder was 24.9 kg, respectively. DSC charts showed that peak temperatures and onset temperatures for all 3 runs of RDX samples were almost identical. All electrostatic spark sensitivity was 0/10 at 1.0 J with a 510-ohm resistor in the discharge circuit

    Rational Approximate Symmetries of KdV Equation

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    We construct one-parameter deformation of the Dorfman Hamiltonian operator for the Riemann hierarchy using the quasi-Miura transformation from topological field theory. In this way, one can get the approximately rational symmetries of KdV equation and then investigate its bi-Hamiltonian structure.Comment: 14 pages, no figure

    Dragging a polymer chain into a nanotube and subsequent release

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    We present a scaling theory and Monte Carlo (MC) simulation results for a flexible polymer chain slowly dragged by one end into a nanotube. We also describe the situation when the completely confined chain is released and gradually leaves the tube. MC simulations were performed for a self-avoiding lattice model with a biased chain growth algorithm, the pruned-enriched Rosenbluth method. The nanotube is a long channel opened at one end and its diameter DD is much smaller than the size of the polymer coil in solution. We analyze the following characteristics as functions of the chain end position xx inside the tube: the free energy of confinement, the average end-to-end distance, the average number of imprisoned monomers, and the average stretching of the confined part of the chain for various values of DD and for the number of monomers in the chain, NN. We show that when the chain end is dragged by a certain critical distance x∗x^* into the tube, the polymer undergoes a first-order phase transition whereby the remaining free tail is abruptly sucked into the tube. This is accompanied by jumps in the average size, the number of imprisoned segments, and in the average stretching parameter. The critical distance scales as x∗∼ND1−1/νx^*\sim ND^{1-1/\nu}. The transition takes place when approximately 3/4 of the chain units are dragged into the tube. The theory presented is based on constructing the Landau free energy as a function of an order parameter that provides a complete description of equilibrium and metastable states. We argue that if the trapped chain is released with all monomers allowed to fluctuate, the reverse process in which the chain leaves the confinement occurs smoothly without any jumps. Finally, we apply the theory to estimate the lifetime of confined DNA in metastable states in nanotubes.Comment: 13pages, 14figure

    In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

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    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid semiconductors/superconductors transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray defraction, electron microscopy, and energy dispersive x-ray analysis are discussed
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