“bell hole”的概念、定义、翻译、参考文献-科学参考

单词	bell hole
释义	bell hole [`bel ´hōl] ^{MINING ENGINEERING} 1. One of the holes or excavations made at the section joints of a pipeline for the purpose of repairs. 2. A conical cavity in a coal mine roof caused by the falling of a large concretion.
随便看	position line position operator position pulse position report position representation position sensor position telemetering position transducer position vector positive positive acceleration positive afterimage positive angle positive area positive axis positive bias positive birefringence positive charge positive click adjustment positive clutch positive column positive correlation positive crystal positive definite positive derail

科学参考收录了103327条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。