Magnets, NMR

Theory of the Magnetic NMR Parameters in Solution General Features of PCM Models... 

The spectrometer used to perform the preliminary SINNMR experiments was a JEOL FX-90Q multinuclear iron-core magnet NMR spectrometer. Although equipped with a variable temperature system to enable the probe temperature to be... 

With the stoichiometry ZrSej 94, zirconium diselenide is a semiconductor with an empty tjg band ( 16.4.3.1). The LijZrSej 94 intercalation compounds show a phase transition when x reaches 0.40. A continuous filling of the octahedral sites of the van der Waals gap (see Fig. 1, 16.4.3.1.) is observed over the whole composition domain (0 < X < 1) according to a classical CdIj-NiAs transition. Electrical, electrochemical, magnetic, NMR and EPR measurements affirm that it is a purely electronic transition. Below X = 0.40 the electrons are localized on zirconium centers, reducing Zr ions Zr above x = 0.40 a metallic behavior is observed. 

Traditional instrumental techniques, such as nuclear magnetic NMR, mass spectrometry infrared (IR) spectroscopy, ultraviolet-visible spectrophotometry, and gas and liquid chromatography and size-exclusion chromatography, are used extensively for purity assessment and molecular structure and molecular weight measurements of monomers and polymers [61]. 

In unilateral NMR, a magnet and the RF communication antenna are placed on the object, which can be much larger than the magnet. With permanent magnets, NMR sensors as small as a computer mouse can be built and positioned on intact objects at different places to measure T2, which goes hand in hand with molecular mobility. 

Current limiters, FCL Ultrahigh-field magnets NMR High-gradient magnetic separation ... 

First superconducting magnet NMR spectrometer (Varian 220 MHz) Varian... 

Magnetic NMR Fre- Electrical Natural dipole quencyin quadrupoh... 

In the first low frequency (20 kHz) ultrasound/ NMR experiments, the ultrasound was delivered to samples in a conventional iron magnet NMR spectrometer using apparatus similar to that shown in Figure 1. The titanium alloy horn used was sufficiently long (77 cm) to enable the piezoelectric device... 

In spite of improvements in the homogeneity and field strength of superconducting magnets, NMR transitions are still of very low energy ( 10 J/spin). Because the transition energy is small with respect to kT (Boltzman constant x temperature) at room temperature, the population difference between the upper and lower energy states represents <0.01% of the total number of molecules. So NMR is a relatively insensitive detection method. This low sensitivity has precluded the use of NMR in trace analysis and minor components in polymers. 

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