0103.核磁共振谱仪发展简史.ppt

* * * * * * * * * * * * * * 80年代初美国建立了几个NMR中心，装备几台谱仪，供地区公用。79年我国引进3台XL-200。 21世纪初，国外NMR实验室拥有多台5、600MHz仪己很普遍。我国已有超导NMR仪330台，少数实验室也有4台以上谱仪。 国家结构基因组计划拟建立类似日本Yokohama的NMR园区。 Our nuclear magnetic resonance (NMR) facility has two complexes, the West and Central NMR Complexes. The West NMR Complex is a building composed of ten hexagons and two core rooms, and the Central NMR Complex is shaped like a Coliseum. The complex buildings were finished in March 2000 and October 2002, respectively. Almost 40 NMR instruments are being used for protein structural and functional analyses. Each NMR machine has a superconducting magnet. We use the magnetic field inside the magnet to measure the signals from proteins. Stray fields also exist outside the magnet, and hence a large space is necessary to contain the stray field. The stray fields should not overlap between the magnets. Therefore, each of our ten strongest magnets is installed within a hexagon, which mimics the shape of the stray field (which is actually round). The magnets are distant from each other. The buildings are made of wood and are covered by aluminum plating; we avoided the use of iron reinforcements, which disturb the magnetic field. Due to the absence of iron, we could allow the margin of the stray field to cross into the wall of the hexagon. If iron had been used in the walls, then larger buildings would have been needed (If we had constructed a much larger iron-reinforced building that could contain all the stray fields from forty magnets, then the construction cost would have been much higher). For weaker magnets, an advanced technology has made it possible to significantly reduce the stray field by shielding the magnet. Actually, we have installed ten 600 MHz shielded magnets in the two central parts surrounded by the hexagons of the West NMR Complex, and seventeen 500~800 MHz shielded magnets in the Central Complex. The interiors of the wooden rooms have natural, unpainted wood paneling, and are qui