Disclosed are methods for performing dynamic nuclear polarization using the polarizing agents described herein. In general, the methods involve (a) providing a frozen sample in a magnetic field, wherein the frozen sample includes a polarizing agent described herein and an analyte with at least one spin half nucleus; (b) polarizing the at least one spin half nucleus of the analyte by irradiating the frozen sample with radiation having a frequency that excites electron spin transitions in the polarizing agent; (c) optionally melting the sample to produce a molten sample; and (d) detecting nuclear spin transitions in the at least one spin half nucleus of the analyte in the frozen or molten sample. In certain embodiments, the polarizing agents can be peptide-based. In these embodiments, the polarizing agents can be readily prepared by solid-phase peptide synthesis.

A method for measuring oil-water distribution using DNP-MRI, comprising adding a free radical for DNP enhanced NMR signal of a water phase or an oil phase in a sample containing oil and water; performing an MRI experiment on the sample, and collecting an MRI image of the sample without DNP enhancement; applying microwave excitation for DNP-MRI experiment under the same MRI experiment condition as step 2, and collecting an MRI image of the sample after DNP enhancement; and comparing the MRI image after DNP enhancement with the MRI image without DNP enhancement. In the MRI image with DNP enhancement, an area with enhanced MRI signal intensity is a selectively enhanced fluid phase distribution area, and an area without obviously changed MRI signal intensity is a non-selectively enhanced fluid phase distribution area. The method is simple, convenient to operate, short in measurement time, and high in measurement efficiency.

A method for separating oil-water two-phase NMR signals by using dynamic nuclear polarization comprising: using a combination of a non-selective free radical and a selective relaxation reagent to selectively enhance an NMR signal of an oil phase or a water phase, the relaxation reagent being capable of selectively suppressing dynamic polarization enhancement of the water phase or oil phase, thus achieving the polarization enhancement of a single fluid phase in the mixed fluid phases and realizing separation of the two-phase signals; or using a selective free radical to selectively enhance the NMR signal of the oil phase or the water phase, thus achieving the polarization enhancement of a single fluid phase in the mixed fluid phases and realizing separation of the oil-water two-phase NMR signals. The method is simple and easy to operate, has a short test time, and can efficiently separate NMR signals of oil and water phases.

The polarization of nuclear spins of a material may be enhanced by encapsulating the material within a reverse micelle.

An electron-nuclear double resonance resonator, having a loop-gap resonator and an elongated lead; the loop-gap resonator comprises a plurality of arc-shaped conductive plates, and the elongated lead connects the arc-shaped conductive plates into a radio-frequency coil; the loop-gap resonator resonates at an electron resonance frequency, and the radio-frequency coil resonates at a nuclear resonance frequency; with the structure of the loop-gap resonator, the separation between an electric field and a magnetic field can be accelerated to ensure the maximization of the ratio of the magnetic field to the electric field inside a resonant resonator; and with the elongated lead, the impact of the lead to a resonance frequency and the mode of the loop-gap resonator is prevented as much as possible, and meanwhile the conductive plates of the loop-gap resonator can be connected into the radio-frequency coil.

An electron-nuclear double resonance resonator, having a loop-gap resonator and an elongated lead; the loop-gap resonator comprises a plurality of arc-shaped conductive plates, and the elongated lead connects the arc-shaped conductive plates into a radio-frequency coil; the loop-gap resonator resonates at an electron resonance frequency, and the radio-frequency coil resonates at a nuclear resonance frequency; with the structure of the loop-gap resonator, the separation between an electric field and a magnetic field can be accelerated to ensure the maximization of the ratio of the magnetic field to the electric field inside a resonant resonator; and with the elongated lead, the impact of the lead to a resonance frequency and the mode of the loop-gap resonator is prevented as much as possible, and meanwhile the conductive plates of the loop-gap resonator can be connected into the radio-frequency coil.

A process for enhancing polarization of .sup.13C for subsequence MRI imaging, the process comprising providing a suspension consisting of a first plurality of particulates having NV centers and a second plurality of particulates for providing internal reflection of light with wavelength for the excitement of NV centers and .sup.13C; and applying light, magnetic field and microwave to said suspension, such that the NV centers are polarized and such that the electron spins of the VN centres are transferred to .sup.13C atoms upon the Rabi frequency of the NV centres matching the Larmor frequency of .sup.13C; wherein the particulates of the second plurality reflect and transmit the light through the suspension such that said light is distributed through said suspension.

In a magnet system: —a superconducting main field magnet (7) generates a magnetic field in a first sample volume (16), —a superconducting additional field magnet (22) generates another field in a second sample volume (24), —a cryostat (2) has a cooled main coil container (6), an evacuated RT (room temperature) covering (4), and an RT bore (14) which extends through the main and the additional field magnets, and —a cooled additional coil container (21) in a vacuum. The RT covering has a flange connection (17) with an opening (19) through which the RT bore extends, a front end of the additional coil container protrudes through the opening into the RT covering such that the additional field magnet also protrudes through the opening into the RT covering, and a closure structure (20) seals the RT covering between the flange connection and the RT bore.

A coil facility for a magnetic resonance installation and a magnetic resonance installation having such a coil facility are provided. The coil facility in this case includes a double-resonant transmit resonator for two frequencies and a first receiver and a second receiver, each for one of the two frequencies. The coil facility has an actuator system for effecting a relative spatial transposition of the transmit resonator, the first receiver, and the second receiver into various settings. In a first setting, only the first receiver, and in a second setting, only the second receiver, for receiving corresponding MR signals is arranged in an examination space that is at least sectionally surrounded by the transmit resonator.

A coil facility for a magnetic resonance installation and a magnetic resonance installation having such a coil facility are provided. The coil facility in this case includes a double-resonant transmit resonator for two frequencies and a first receiver and a second receiver, each for one of the two frequencies. The coil facility has an actuator system for effecting a relative spatial transposition of the transmit resonator, the first receiver, and the second receiver into various settings. In a first setting, only the first receiver, and in a second setting, only the second receiver, for receiving corresponding MR signals is arranged in an examination space that is at least sectionally surrounded by the transmit resonator.