Comment on "Pulsar Velocities and Neutrino Oscillations"

In a recent Letter, Kusenko and Segre proposed a new mechanism to explain the observed proper motions of pulsars. Their mechanism was based on the asymmetric neutrino emission induced by neutrino oscillations in the protoneutron star magnetic field. In this note I point out that their estimate of the asymmetry in the neutrino emission is incorrect. A proper calculation shows that their mechanism at least requires a magnetic field of 10**16 G in order to produce the observed average pulsar velocity.Comment: 4 pages, RevTe

Doubly heavy baryon production at polarized photon collider

We study the inclusive production of doubly heavy baryon $\Xi_{cc}$ at polarized photon collider. Our results show that proper choice of the initial beam polarizations may increase the production rate of $\Xi_{cc}$ approximately 10%.Comment: 9 pages, 5 figure

Spheres and Prolate and Oblate Ellipsoids from an Analytical Solution of Spontaneous Curvature Fluid Membrane Model

An analytic solution for Helfrich spontaneous curvature membrane model (H. Naito, M.Okuda and Ou-Yang Zhong-Can, Phys. Rev. E {\bf 48}, 2304 (1993); {\bf 54}, 2816 (1996)), which has a conspicuous feature of representing the circular biconcave shape, is studied. Results show that the solution in fact describes a family of shapes, which can be classified as: i) the flat plane (trivial case), ii) the sphere, iii) the prolate ellipsoid, iv) the capped cylinder, v) the oblate ellipsoid, vi) the circular biconcave shape, vii) the self-intersecting inverted circular biconcave shape, and viii) the self-intersecting nodoidlike cylinder. Among the closed shapes (ii)-(vii), a circular biconcave shape is the one with the minimum of local curvature energy.Comment: 11 pages, 11 figures. Phys. Rev. E (to appear in Sept. 1999

Self-similarity under inflation and level statistics: a study in two dimensions

Energy level spacing statistics are discussed for a two dimensional quasiperiodic tiling. The property of self-similarity under inflation is used to write a recursion relation for the level spacing distributions defined on square approximants to the perfect quasiperiodic structure. New distribution functions are defined and determined by a combination of numerical and analytical calculations.Comment: Latex, 13 pages including 6 EPS figures, paper submitted to PR

The Quantum Cosmological Wavefunction at Very Early Times for a Quadratic Gravity Theory

The quantum cosmological wavefunction for a quadratic gravity theory derived from the heterotic string effective action is obtained near the inflationary epoch and during the initial Planck era. Neglecting derivatives with respect to the scalar field, the wavefunction would satisfy a third-order differential equation near the inflationary epoch which has a solution that is singular in the scale factor limit $a(t)\to 0$. When scalar field derivatives are included, a sixth-order differential equation is obtained for the wavefunction and the solution by Mellin transform is regular in the $a\to 0$ limit. It follows that inclusion of the scalar field in the quadratic gravity action is necessary for consistency of the quantum cosmology of the theory at very early times.Comment: Tex, 13 page

In-medium Properties of Θ+\Theta^{+} as a Kπ\piN structure in Relativistic Mean Field Theory

The properties of nuclear matter are discussed with the relativistic mean-field theory (RMF).Then, we use two models in studying the in-medium properties of $\Theta^+$: one is the point-like $\Theta^*$ in the usual RMF and the other is a K$\pi$N structure for the pentaquark. It is found that the in-medium properties of $\Theta^+$ are dramatically modified by its internal structure. The effective mass of $\Theta^+$ in medium is, at normal nuclear density, about 1030 MeV in the point-like model, while it is about 1120 MeV in the model of K$\pi$N pentaquark. The nuclear potential depth of $\Theta^+$ in the K$\pi$N model is approximately -37.5 MeV, much shallower than -90 MeV in the usual point-like RMF model.Comment: 8 pages, 5 figure

Development of a carbon emission calculations system for optimizing building plan based on the LCA framework

Life cycle thinking has become widely applied in the assessment for building environmental performance. Various tool are developed to support the application of life cycle assessment (LCA) method. This paper focuses on the carbon emission during the building construction stage. A partial LCA framework is established to assess the carbon emission in this phase. Furthermore, five typical LCA tools programs have been compared and analyzed for demonstrating the current application of LCA tools and their limitations in the building construction stage. Based on the analysis of existing tools and sustainability demands in building, a new computer calculation system has been developed to calculate the carbon emission for optimizing the sustainability during the construction stage. The system structure and detail functions are described in this paper. Finally, a case study is analyzed to demonstrate the designed LCA framework and system functions. This case is based on a typical building in UK with different plans of masonry wall and timber frame to make a comparison. The final results disclose that a timber frame wall has less embodied carbon emission than a similar masonry structure. 16% reduction was found in this study

Nonpolar resistive switching in Cu/SiC/Au non-volatile resistive memory devices

Amorphous silicon carbide (a-SiC) based resistive memory (RM) Cu/a-SiC/Au devices were fabricated and their resistive switching characteristics investigated. All four possible modes of nonpolar resistive switching were achieved with ON/OFF ratio in the range 10 6-10 8. Detailed current-voltage I-V characteristics analysis suggests that the conduction mechanism in low resistance state is due to the formation of metallic filaments. Schottky emission is proven to be the dominant conduction mechanism in high resistance state which results from the Schottky contacts between the metal electrodes and SiC. ON/OFF ratios exceeding 10 7 over 10 years were also predicted from state retention characterizations. These results suggest promising application potentials for Cu/a-SiC/Au RM