Wei Yuanyuan

Beam dynamics studies on BEPC- II storage rings at the commissioning stage

During the 1st and 2nd stages of the commissioning of the upgrade project of the Beijing Electron Positron Collider (BEPC II), which started on Nov. 12, 2006 and Oct. 24, 2007, respectively, we got the luminosity one tenth of its design value, provided beams to synchrotron radiation users for about 4 months, and studied beam dynamics as well. In this paper, some beam dynamics studies on the storage rings and their preliminary results are given.

Research of Ontology-Driven Agricultural Search Engine

An ontology-driven retrival method for agriculture search engine is proposed in this paper. An agricultural products ontology was built, with that a semantic expanson algorithm for search keyword was achieved when executing search task. This process supply semantic-level retrieval service for search engine users. The goal is to improve intelligentization of agriculture search engine.

Measurement and correction of coupling in BEPC II

The existing linear coupling theory and representation method are introduced briefly. The so-called local and global coupling is discussed in more detail. The vertical orbit distortion excited by a horizontal corrector is represented with the coupling parameters at the corrector and the observation point. The formula is used to measure the coupling in BEPCII. In order to correct the coupling, vertical correctors are used to change the vertical orbit through sextupoles by a least square method. We also introduce and review other frequently used coupling measurement/tuning methods used in our machine.