Influence of Heat Sink on the Mold Temperature of Gypsum Mold Used in Injection Molding.

Gypsum molds have been developed as an alternative for the Rapid tooling (RT) method used in injection molding. However, the poor capability of the heat delivery forces the gypsum mold to operate under a high-risk condition, and distortion of the molded part becomes apparent. The goal is to investigate the effect of a heat sink on the reduction of the gypsum mold temperature and to establish a methodology for the heat sink design.

[Meta-analysis study on risk factors of colorectal cancer].

OBJECTIVE: To evaluate the risk factors of colorectal cancer in China. METHODS: The results of 14 case-control studies from 1988 to 2000 were analyzed by means of Meta-analysis. The total numbers of cases and controls were 5034 and 5205 respectively.