Methods and systems are provided that combine NMR and IR spectroscopy measurements on a rock sample to determine data representing at least one property of the rock sample. In one embodiment, cuttings can be split into first and second lots. Results of an NMR measurement performed on the first lot of cuttings without cleaning can be analyzed to determine pore volume of the cuttings. Results of an IR spectroscopy measurement performed on the second lot of cuttings after solvent cleaning can be analyzed to determine matrix density of the cuttings. Porosity can be determined from the pore volume and matrix density of the cuttings. In another embodiment, combined NMR and IR spectroscopy measurements can be performed on an unprepared rock sample (without solvent cleaning) to characterize properties of kerogen in the rock sample and porosity. In another aspect, a method is provided that employs multi-nucleic NMR measurements to determine porosity.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

The present invention discloses a method of species identification and quality detection of liquid-like samples based on nuclear magnetic resonance technology. In this invention, a two-dimensional relaxation signal containing the .sup.1H T.sub.1 and T.sub.2 relaxation properties of liquid-like samples is obtained by applying a specially designed composite pulse sequence to liquid-like samples, and a fingerprint spectrum from this signal is established. The fingerprint spectrum can be associated with the essential characteristics of the tested sample, thus can be used to distinguish a specific liquid-like sample from the others. The fingerprint spectrum can be easily converted into a digital form, which is not only suitable for constructing big data of fingerprint spectrum for liquid-like samples, but also can be used for quality detection and authenticity judgment of liquid-like samples based on artificial intelligence. The present invention has the advantages of no need for sample pretreatment, non-destructive sample testing, convenience, quickness, excellent operability, good stability and reproducibility, etc., which can be used for species identification and quality detection of a variety of liquid-like samples, which has a wide application value.

A B.sub.0-mapping method determines the spatial distribution of a static magnetic field in a pre-selected imaging zone comprising computation of the spatial distribution of a static magnetic field from a spatial distribution of spin-phase accruals between magnetic resonance echo signals from the imaging zone and an estimate of the proton density distribution in the imaging zone. The invention provides the field estimate also in cavities and outside tissue. Also the field estimate of the invention suffers less from so-called phase-wraps.

A method includes screening heterogeneity of a rock sample using nuclear magnetic resonance testing to determine a composition of the rock sample, drilling at least one smaller rock sample representative of the determined composition, and testing the at least one smaller rock sample with mercury injection capillary pressure to obtain a capillary pressure distribution of the at least one smaller rock sample. The method further includes decomposing a T.sub.2 distribution from the nuclear magnetic resonance testing and the capillary pressure distribution using Gaussian fitting to identify multiple pore systems, where the small ends of the Gaussian fitted T.sub.2 distribution and the Gaussian fitted capillary pressure distribution are overlapped for at least one of the identified pore systems.

Techniques for determining grain density of a rock sample include identifying an untreated rock sample that includes a solid matrix and a fluid entrained within the solid matrix; measuring, using a gas porosimeter, a grain density of the untreated rock sample; measuring, using nuclear magnetic resonance (NMR), a volume of the fluid entrained within the solid matrix; and determining, based on the measured grain density of the untreated rock sample and the measured volume of the fluid, a grain density of the solid matrix of the untreated rock sample.

The present disclosure provides NMR relaxation methods for characterizing iron carbohydrate drug products. The methods measure .sup.13C and .sup.1H nuclei relaxation parameters such as T1 and PWHH include performing 2D T1 NMR, 1D .sup.13C NMR and .sup.1H NMR to characterize certain physiochemical properties of iron sucrose drug products, for purposes of assessing bioequivalence between a tested iron sucrose product and a comparator product. The disclosure further provides a novel Fe(III)/Fe(II) reduction method using a new reducing agent Na.sub.2S.sub.2O.sub.5 and an .sup.1H NMR method to monitor the Fe(III)/Fe(II) reduction process.

A nuclear magnetic resonance (NMR) system-based substance measurement method, including: acquiring several echo signals of an NMR pulse sequence varying in echo spacing from a substance to be measured followed by processing to obtain several signals varying in transverse relaxation and diffusion attenuation; and fitting, in combination with the prior knowledge, the signals to obtain the diffusion coefficient, transverse relaxation time or/and content weight of individual components of the substance to be measured. This application further provides a substance measurement system including a console, a magnet module, and an NMR system.

A subject S to which .sup.17O gas has been administered is placed within a fixed uniform static magnetic field of an NMR apparatus 1. The subject is irradiated, through proton coupling, with an excitation pulse produced using a pulse sequence having a short cycle time of 20.4 msec or less, preferably 10.4 msec or less, and more preferably 5.6 msec or less. An NMR signal generated due to .sup.17O nuclei of .sup.17O water produced within the subject by oxygen metabolism of the .sup.17O gas being excited by irradiation with the excitation pulse is detected with high sensitivity and is processed in accordance with a prescribed imaging sequence in which an MRS sequence is used.

A method of using the relaxation rate (R.sub.1 and/or R.sub.2) of solvent NMR signal to noninvasively assess whether viral capsids in a capsid preparation are full or empty, and the percentage of full capsids if the vial contains a mixture of full and empty capsids. The method can simply, rapidly, and non-invasively prove the safety and potency of the capsid preparation and thus whether the capsid preparation can be approved for clinical use, without requiring any sample preparation or reagent addition.