【導讀】新技術(shù)勘察地下水已成為當務之急。目前，唯一能直接探測地下水的地球。物理方法就是地面核磁共振找水方法。然而1kHz～3kHz的環(huán)境電。磁噪聲對根據(jù)此方法研制的核磁共振找水儀影響很大。本文針對這種情況。實驗選取測點提供依據(jù)。本噪聲測量裝置通過大量室內(nèi)和野。外實驗，驗證了該裝置能夠有效地評估電磁噪聲的大小。

　　

【正文】 益總增益 (dB) 前放高增益總增益 (倍 ) 10 35478 1614191 11 39084 1778279 12 42104 1915667 13 44450 2022437 14 49720 2262221 15 53062 2414238 16 56624 2576321 吉林大學本科畢業(yè)論文 (設計 ) 33 英文原文 ： Imaging of groundwater with nuclear magic resonance Marian Hertrich The method of surface nuclear magic resonance (SNMR) is a relatively new geophysical technique that exploits the NMRphenomenon for a quantitative determination of the subsurface distribution of hydrogen protons, . water molecules of groundwater resources, by nonintrusive means. The idea to employ NMR techniques within the Earth’s magic field to derive subsurface 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 fieldready 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 Hydroscopeequipment 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 mercial 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 2020, Madrid 2020), and followedup 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 吉林大學本科畢業(yè)論文 (設計 ) 34 mercially available. The new systems extend the available technical possibilities towards improved noise mitigation schemes and multichannel 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 plexvalued signals of measurements on conductive ground and the calculation of surface NMR signals with separated transmitter and receiver loops. The latter feature has been studied in detail by Hertrich and coworkers which revealed that a series of measurements at multiple offsets along a profile provides sufficient sensitivity to allow for high resolution tomographic inversion. A fast and efficient tomographic inversion scheme has been developed that provides the correct imaging of 2D subsurface structures from a series of surface measurements. Various geophysical techniques, like geoelectrics, electromagics,georadar and seismics, are routinely used in a structural mapping sense in hydrogeology, to delineate bedrock and sometimes determine depth of the water table and other major geological boundaries. But surface NMR is the only technique that allows a quantitative determination of the actual water content distribution in the subsurface. Near surface aquifers are the major source of drinking water worldwide. Additionally, these aquifers might be substantially affected by cultural pollution, mismanagement and natural retreat in the ongoing climate change. But also in many other environmental problems groundwater plays a key role. Examples are unstable permafrost and hillslope stability in the progressive global warming or dynamics of glaciers and icesheets. For those issues surface NMR may provide essential information in high resolution imaging of the subsurface water content distribution and monitoring of groundwater dynamics. 吉林大學本科畢業(yè)論文 (設計 ) 35 In conventional NMR applications (. spectroscopy,medical imaging, nondestructive material testing) the excitation of the spin magization is in most cases induced and recorded by uniform secondary magic fields such that the recorded signal amplitude can be calibrated by samples of known spin density and the experiment can be designed such that perfectly controlled flip angles are obtained. By contrast, in surface NMR none of these requirements can be met and the amplitude of the recorded signal has to be quantitatively derived for nonuniform fields and the resulting arbitrary flip angles. Therefore, in this review article, a prehensive derivation of the surface NMR signal is given and the formulations of the problem for 1D and 2D conditions are presented. Stateoftheart inversion techniques are needed to derive subsurface models of water content distribution from measured field data stateoftheart inversion techniques are needed and are applied with appropriate estimates of the reliability of those models given. The observed NMR relaxation times may in general provide additional information about the aquifer properties by their dependency on the pore space geometry, but their determination and interpretation are somewhat limited pared to conventional laboratory NMR techniques. A short account is given on possible schemes of relaxation time determination and future directions of surface NMR research. Since measured surface NMR signals substantially depend on the local settings of the Earth’s magic field and the subsurface resistivity distribution, the dependency on these parameters is described and their variability throughout the Earth is shown and accounted for in terms of likely response. As an example of stateoftheart surface NMR measurements,the inversion and interpretation of a real data set from a wellinvestigated test site is presented. 36 中文翻譯 ： 地下水核磁共振成像 瑪麗安 赫特里希 地面核磁共振技術(shù)（ SNMR）是一種相對較新的地球物理技術(shù)，利用核磁共振現(xiàn)象，通過無干擾手段，定量測定地下氫質(zhì)子的分布，即地下水資源的水分子。瓦里安首次提出了在地磁場中運用核磁共振技術(shù)獲得地下水含量的 這種想法。但是直到