A nondestructive method for express testing of the state of condensed media is considered. The method is based on the developed new design of a small-sized nuclear magnetic resonance (NMR) spectrometer. The proposed engineering solutions and techniques have made it possible to detect weak-field NMR signals from various nuclei (that have magnetic moments) in a small (less than 0.3 cm³) volume of a condensed medium. This has extended significantly the capabilities of the NMRbased nondestructive method of express testing of condensed media, especially for the purposes of ecological monitoring of hard-to-reach territories. Results of experimental research of various media are presented.

A method to measure weak magnetic fields by a nuclear-resonance nutation magnetometer with a flowing liquid is considered. Requirements and conditions that should be imposed on different structural elements of the magnetometer and the parameters of the liquid are determined experimentally and theoretically. Appropriate liquids are found experimentally. The measuring probe of the magnetometer is tested with pure water. Ways to further refine the magnetometer and to improve its accuracy are suggested.

A technique for studying the magnetic susceptibility of colloidal solutions in a hermetically sealed glass volume (a ferrofluidic cell) is proposed. Experimental investigations have shown that...

The design of a compact nuclear magnetic relaxometer is described. This relaxometer is capable of measuring longitudinal T ₁ and transverse T ₂ relaxation times of condensed media in a weak magnetic field with B ₀ = 62 mT. The Giulotto method in a weak magnetic field is used in the relaxometer design to measure T ₁. The NMR signal accumulation circuit has been developed for measuring relaxation times of small-volume samples (1.0–1.5 mL) at a signal-to-noise ratio of 1.2.