Research On The Technology Of Nuclear Magnetic Resonance Microscopy

Nuclear magnetic resonance (NMR) is a phenomenon of energy absorption and emission produced by radio frequency electromagnetic fields interact with Magnetic nucleus. Using this physical phenomenon can do research on imaging, basis on this phenomenon human have developed magnetic resonance imaging study and magnetic resonance microscopy. Commercial spectrometer is very expensive, isn't convenient for using in laboratory. Designing a magnetic resonance spectrometer with low price and good performance using for Low-strength-grade intensity has practical significance and economic outlook, and has great significance for the popularize and apply of magnetic resonance spectrometer using for Low-strength-grade intensity magnet.This paper take a research on nuclear magnetic resonance (NMR) microscopy technology, mainly research on its magnet technology and spectrometer technology. Work on the following three aspects:One thing is designing and manufacture a NdFeB N52 magnet. By means of reading paper, I design a NdFeB N52 magnet model by using Ansoft 12, and doing the analog calculate on magnet. Then constantly change its various parameters, in order to finding the best size. At last, I have get the wanted magnet field with 0.6T. Then I buy some NdFeB N52 in the market. After polishing, jointing and incising, I magnetizing it, in this way I manufacture a magnet. And then I use a teslameter to measure its field, verifying the theoretical value.The second thing is designing and manufacture a digital transmitter unit that based on one frequency conversion Technology. The transmitter unit is controlled by Multifunctional data acquisition card PCIe-6323. The transmitter adopts DDS(direct digital synthesis) technology and implements fully digital orthogonal modulation and one up-conversion with one piece of AD9857.It solves not only the difficult problemof phase control in analog transmitter, but also the error of analog mixing in two up-conversion.The third thing is designing and manufacture a digital receiver unit that based on one frequency conversion Technology. The receiving system is controlled by Multifunctional data acquisition card PCI-7200. The receiver adopts digital direct down-conversion technology and implements fully digital one down-conversion with one piece of AD9244 and one piece of AD6620.lt avoids complex processing of phase correction of two orthogonal signals in analogue technique, improves the overall performance of the receiver, and solves the error of analog mixing in two down-conversion.