【作者】 孙丽茹；

【导师】 段清明；

【作者基本信息】 吉林大学 ， 电力电子与电力传动， 2008， 硕士

【摘要】 寻找可用的淡水资源是解决水资源缺乏的有效方法。将核磁共振找水方法和瞬变电磁法结合起来进行找水,可减小反演中的多解性,且分辨率互补。论文首先论述了核磁共振找水仪发射装置的工作原理和瞬变电磁法找水仪发射装置的工作原理,通过对这两种找水仪发射装置及其工作原理的剖析,可知这两个发射装置都由发射控制模块、驱动模块和发射主回路组成,且发射装置的发射主回路都可由H桥逆变电路构成。可以用一台核磁共振与瞬变电磁联用仪发射装置来分别产生核磁共振找水仪的激发脉冲信号和瞬变电磁找水仪的激发脉冲信号,从而由一个发射装置实现两种找水的方法。论文提出了核磁共振与瞬变电磁联用仪发射装置的设计方案,并且完成了样机的研制。论文主要论述了核磁共振与瞬变电磁联用仪发射装置研制过程中的两个关键部分:发射控制模块的设计和发射主回路的仿真。系统测试部分包括性能指标测试和野外实验,在系统测试部分对实验结果进行了详细的分析。最后作了全文总结,并给出了进一步工作的建议。更多还原

【Abstract】 Water is important to people on the earth. The water distributing is not the same in many places. The lack of water is obvious in our China and it influences our development and people’life. Detecting underground water is an effective way to solve the water problem.There are many underground water detecting methods. The SNMR(Surface Nuclear Magnetic Resonance ) and the TEM(Transient EM) are two effective methods. The combination of the two methods can give more correct results.The combination of the two methods can get more accurate result of the underground water portrait, and the precision of profile can be improved more.SNMR method is a direct water detecting method, but the exploration depth is less than 150 meters. The instrument first works in SNMR method when the exploration depth is less than 150 meters while the transmitter of the instrument transmit the 40ms alternative current signals. The H proton of the underground water then will be inspired and generate the weak NMR FID signal. The transmitting frequency is near to the Lamor frequency. The NMR signal is then picked up by the receiving coil. The exploration depths of TEM method will be 0-400 meters or more. When the exploration depth is above 150 meters, the instrument works in TEM method and transmits the TEM signal. The receiving coil will receive the signal by the underground object and gives out the useful information.The SNMR and TEM instrument have some same configurations which will be useful to the combined machines.1、The transmitters of the two instruments are both made up of the transmitting control module, the drive module and the main transmitting circuit. 2、The main transmitting circuit is both composed by the H bridge made up of power switches.And we can use one multifunctional transmitter to realize the two kinds of wave transmitting.The first chapter introduces the significance, application and study condition both native and abroad. The second chapter analyzes the basic theories of the two exploration methods. The next chapter introduces the design and realization of the main transmitting circuit. The forth chapter gives the simulation result of the transmitting circuit. The fifth chapter gives the testing result of the multifunctional transmitter. The last chapter summarizes the whole paper.The multifunctional transmitting instrument realizes such functions:Transmitting frequency: 1 - 4 kHz. The time and frequency of transmitting current pulse is controlled by software program. The duration of transmitting current is 5-40ms and the maximum transmitting current is 450A.更多还原