Abstract: The phase encoding of NMR information is performed using rf pulse sequences. The rf pulse sequences produce a substantially continuous phase variation cross the resonant frequency range of the atoms of an object in order to perform phase encoding. Some of the pulses may be tailored pulses, with each tailored rf pulse including frequencies which cover a bounded continuous frequency range. Either the phase or the amplitude of each tailored rf pulse varies with frequency across this continuous range. If the amplitude is linearly variant across the range, the phase is constant, but if the phase is linearly variant across the range, the amplitude is constant. The tailored rf pulses may be applied in the presence of pulsed magnetic gradient fields of the conventional type to produce the phase variation.

Abstract: An adjustable magnetic field for nuclear magnetic resonance diagnostic devices is provided by a set of extending ferromagnetic bars mounted in one of a pair of opposing magnetic pole members. A second set of extending ferromagnetic bars may be mounted in the other magnetic pole opposite the first set of bars. Adjustment of the magnetic field may be achieved either by moving the ferromagnetic bars or by controlling current flow through coils placed about at least some of the ferromagnetic bars. In order to detect the actual field strength and configuration to provide for the requisite control signals, an array of Hall effect detectors is employed.

Abstract: A method of measuring a static magnetic field distribution in a nuclear magnetic resonance (NMR) inspection system which comprises magnetic field generator for producing a static magnetic field, inclination or gradient magnetic fields and a high-frequency magnetic field, a signal detector for sensing nuclear magnetic resonance signals from an inspection sample, a computer for processing output signals from the signal detector and an output device for providing a computational result of the computer, wherein a time interval t.sub.1 from the center of a 90.degree.-pulse high-frequency magnetic field to the center of a 180.degree.-pulse high-frequency magnetic field is made different by a time difference t.sub.0 from a time interval t.sub.2 from the center of the 180.degree.-pulse high-frequency magnetic field to a peak of a spin echo, so that static magnetic field distribution is calculated based on the computer output which corresponds to the difference of the two time intervals.

Abstract: A method of defining homogeneous rock formation zones along a borehole on the basis of logs, uses two logs, a lithological log and a log relating to the impregnation fluids. Individual limits of zones are determined by reproducing or reshaping each of the logs in the form of rectangular zones or crenellations, preferably rough crenellations for the first log and smoothed crenellations for the second log, and the individual limits are combined to obtain synthetic limits, some of the individual limits belonging to the first log only preferably being subsequently eliminated when the first log is smoothed.