A man found a cocoon of a butterfly. One day a small opening appeared. He sat and watched the butterfly for several hour......

针对某电厂锅炉水冷壁管发生的鼓包、爆管事故，通过化学成分分析、显微组织观察、力学性能测试等方法分析了爆管和鼓包的原因。结果......