气工程及其自动化毕业论文外文文献翻译英文：地下核磁振成像.doc

英文原文： Imaging of groundwater with nuclear magnetic resonance Marian Hertrich The method of surface nuclear magnetic resonance (SNMR) is a relatively new geophysical technique that exploits the NMR-phenomenon for a quantitative determination of the sub-surface distribution of hydrogen protons, i.e. water molecules of groundwater resources, by nonintrusive means. The idea to employ NMR techniques within the Earth’s magnetic field to derive sub-surface water contents was first proposed by Varian. It was not until the late 1970s that a group of Russian scientists took up the idea and developed the first field-ready prototype of surface NMR equipment in the 1980s. It allowed for the first time the recording of NMR signals from groundwater at considerable depths in the Earth. Numerous field applications with the Russian Hydroscope-equipment encouraged the ongoing technical developments for about a decade. They were supported by several studies on the modeling, inversion and processing of surface NMR data. Surface NMR became better known to western scientists when the first commercial equipment was launched by Iris Instruments (France) in 1996. A few groups worldwide actively pursued the fundamentalresearch and applications of surface NMR. Over the past decade the continuous progress and experience has been reported at periodic international workshops (Berlin 1999, Orleans 2003, Madrid 2006), and followed-up publishing special issues of peer reviewed journals devoted to surface NMR. Continuous technical development of surface NMR measurements has been carried out and, recently, two new suites of surface NMR hardware have been made commercially available. The new systems extend the available technical possibilities towards improved noise mitigation schemes and multi-channel recording. Major advances in the development of surface NMR were triggered by a revision of the fundamental equations proposed byWeichman et al. The improved formulation allows the correct calculation of