Exactly 600 years ago this month the great ming armada weighed anchor in nanjing , on the first of seven epic voyages as far west as africa ? almost a century before christopher columbus ' s arrival in the americas and vasco da gama ' s in india 就在600年前的这个月（明永乐三年( 1405 )六月十五日） ，这支雄壮的明朝船队在江苏太仓刘家港起锚首航，七次历史性航行由此展开，最远最西曾抵达非洲，而且比哥伦布到达美洲以及达.伽马到达印度早了将近一个世纪。
This paper gives a comprehensive description of the development of aerogeophysical techniques in western countries and recounts such instruments as aeromagnetometer and gamma spectrometer , the newest aeromagnetic , aeroelectromagnetic and airborne gravity surveying system as well as data - processing software 摘要本文综述了西方国家航空物探技术的发展动态，介绍了最新航空磁力仪、伽马能谱仪，以及最新航磁、航电、航重测量系统、数据处理软件。
Take the glutenite reservoir in south slope of chenjiazhuang rize as a case , introduced are the applications of natural gamma ray spectrometry logging data , such as zonation of reservoir , unpermeable layer and fracture discrimination , analysis of formation sensitivity as well as recognition of oil layer , etc 以陈家庄凸起南斜坡带砂砾岩油藏为例，介绍了自然伽马能谱测井在储层划分、隔层和裂缝的识别、储层敏感性分析以及油层识别等方面的应用。
