Taking the PPM catalogue as the initial reference catalogue and using the central overlapping method with the iteration process, we obtained the position and proper motion of NGC7302 and high - precision positions and proper motions of 11 stars around the galaxy.

Using the stellar proper motions reduced from the observational data of photographic plates taken with the 40 cm double astrograph of Shanghai Astronomical Observatory, the distribution parameters and membership probabilities of stars in the region of the open cluster NGC6530 are determined on the basis of the maximum likelihood principle and given in tabular form.

Carrying out a kinematical analysis of the Galaxy for proper-motion systems of the FK5 and Hipparcos, a large difference in proper motions between two systems is found, even if the precessional correction to the FK5 system has been considered.

In this paper,performance-based fire safety design concept was adopted to analyze the fire safety objective that the smoke evacuation system of Laoshan bicycle racing centre should achieve,fire scenarios were designed and the performance of natural smoke evacuation system was studied by using CFD techniques.

Was the injured riding bicycle at the time of accident?;

Design and experiment of snake-shaped spring shocker absorber in bicycle;

Use of insulated iron powders in a bicycle permanent magnet electric motor;