| 摘要 |
<p>A preform is formed by stacking core elements that are coated with prepregs. By heating the preform at a temperature at which the core elements do not thermally shrink, the prepregs are preliminarily hardened, and prepregs that are in contact with each other are caused to adhere to each other. Then, the prepregs are definitively hardened and the core elements are thermally shrunk by heating the preform at a temperature at which the core elements thermally shrink.</p> |
