On the blow-up structure for the generalized periodic Camassa-Holm and Degasperis-Procesi equations

Considered herein are the generalized Camassa-Holm and Degasperis-Procesi equations in the spatially periodic setting. The precise blow-up scenarios of strong solutions are derived for both of equations. Several conditions on the initial data guaranteeing the development of singularities in finite time for strong solutions of these two equations are established. The exact blow-up rates are also determined. Finally, geometric descriptions of these two integrable equations from non-stretching invariant curve flows in centro-equiaffine geometries, pseudo-spherical surfaces and affine surfaces are given.Comment: 26 page

Transport model study of nuclear stopping in heavy ion collisions over an energy range from 0.09A GeV to 160A GeV

Nuclear stopping in the heavy ion collisions over a beam energy range from SIS, AGS up to SPS is studied in the framework of the modified UrQMD transport model, in which mean field potentials of both formed and "pre-formed" hadrons (from string fragmentation) and medium modified nucleon-nucleon elastic cross sections are considered. It is found that the nuclear stopping is influenced by both the stiffness of the equation of state and the medium modifications of nucleon-nucleon cross sections at SIS energies. At the high SPS energies, the two-bump structure is shown in the experimental rapidity distribution of free protons, which can be understood with the consideration of the "pre-formed" hadron potentials.Comment: 15 pages, 7 figure

Postmark Date Recognition Based on Machine Vision

AbstractFor the purpose of information management on postmark according to the date, the paper put forward a method of postmark date recognition based on machine vision, which could meet the demands of personal postmark collectors. On the basis of the relative theories of machine vision, image processing and pattern recognition, the overall process is introduced in the paper from postmark image acquisition to date recognition. Firstly, threshold method is used to generate binary image from smoothed postmark image. So region of date numbers could be extracted from binary image according to different region features. Then regions of date numbers which are connected or broken could be processed through mathematical morphology of binary image. Individual regions of date numbers are obtained for recognition. Finally, classification and pattern recognition based on support vector machine make date numbers classified and date recognition is implemented correctly

IS THE HIGH-TOP SHOE MORE PROTECTIVE IN LANDING ON A TILTED SURFACE: A KINEMATIC AND ELECTROMYOGRAPHIC EVALUATION

The purpose of this study was to explore the effect of high-top and low-top shoes on ankle inversion kinematics and pre-landing EMG activation of ankle evertor muscles during the landing on a combined inverted and plantarflexed surface. Thirteen male subjects were instructed to wear high-top & low-top shoes to execute self-initiated drop landings in each of the 8 landing conditions, i.e. 2 shoes × 4 surface conditions, on an inverted (or combined plantarflexed) platform. Ankle inversion kinematics and the EMG from the tibialis anterior, peroneal longus, and peroneus brevis muscles were collected simultaneously. The results indicated that shoe collar heights did not influence the ankle inversion kinematics during landing. However, wearing high-top shoes resulted in a significant posterior onset time of the tibialis anterior and peroneus brevis muscles, and lowered the pre-landing EMG activation of ankle evertor muscles prior to foot contact during landing on the inverted surface