Actively-shielded ultrahigh field MRI/NMR superconducting magnet design

Active shielding technology has been widely applied to the superconducting magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) magnets design, revealing excellent performance on the stray field control. For such a highly homogeneous field superconducting magnet design, an appropriate optimization strategy is essential to guarantee the magnetic field homogeneity in the central region and the expected 5 Gauss line range, especially for the ultrahigh field superconducting magnet. Based on the compensating field optimization method, an actively-shielded whole-body 14T MRI magnet and an actively-shielded 1.3GHz NMR magnet were presented, and detailed analyses were conducted to evaluate the feasibility of the designs. The developed magnet design method, coil pattern, wire arrangement, and stress/strain adjustment will be used to guide the corresponding project implementation.

The development of the magnetic system of sensor for PMR-analyser

The enhancement of the measuring instruments accuracy has always been the most crucial task for engineers and scientists. In particular, in the field of nuclear magnetic resonance, the creation of uniform magnetic field often defines the results of measurements, therefore the main task of this study is to develop Halbach magnet array based on design characteristics of developing NMR-analyzer. The research describes the development process of the main sensor’s magnetic system components for continuous-flow portable NMR-analyzer. The scientific paper makes a different variations analysis of Halbach magnet arrays on the degree of the magnetic field homogeneity, shows the process of development and production of the 3D-framework for Halbach magnet array for NMR-analyzer. The article also gives information on the design of quartz generator based on Pierce oscillator circuit for receiver-transmitter coil of the NMR-analyzer’s sensor. The results could be useful for the magnetic sensors design with high degree of homogeneity, measuring instruments and devices using the method of nuclear magnetic resonance in its foundation.

Measurement Science is the Science of Sciences - There is no Science without Measurement

Omnia in mensura et numero et pondere disposuisti is a famous Latin phrase from Solomon’s Book of Wisdom, dated to the mid first century BC, meaning that all things were ordered in measure, number, and weight. Naturally, the wisdom is appearing in its relation to man. The Wisdom of Solomon is understood as the perfection of knowledge of the righteous as a gift from God showing itself in action. Consequently, a natural and obvious conjecture is that measurement science is the science of sciences. In fact, it is a basis of all experimental and theoretical research activities. Each measuring process assumes an object of measurement. Some science disciplines, such as quantum physics, are still incomprehensible despite complex mathematical interpretations. No phenomenon is a real phenomenon unless it is observable in space and time, that is, unless it is a subject to measurement. The science of measurement is an indispensable ingredient in all scientific fields. Mathematical foundations and interpretation of the measurement science were accepted and further developed in most of the scientific fields, including physics, cosmology, geology, environment, quantum mechanics, statistics, and metrology. In this year, 2020, Measurement Science Review celebrates its 20th anniversary and we are using this special opportunity to highlight the importance of measurement science and to express our faith that the journal will continue to be an excellent place for exchanging bright ideas in the field of measurement science. As an illustration and motivation for usage and further development of mathematical methods in measurement science, we briefly present the simple least squares method, frequently used for measurement evaluation, and its possible modification. The modified least squares estimation method was applied and experimentally tested for magnetic field homogeneity adjustment.

A Triple Layer of Immiscible Solvents for NMR Sample Preparation: Enhanced Sensitivity and Reduced Deuterated Solvent for Observation of Heteronuclei

<p>Organic chemistry labs routinely perform NMR in a standard 5 mm NMR tube. NMR sample is prepared by filling the lowermost 4 cm length of a regular 5 mm 0.d. tube that holds approximately 0.55 ml of a deuterated solvent. This is actually a sample dilution procedure as the signal mainly comes from the central part, i.e. 1.8 cm length sample that fits the typical coil length of 1.8 cm in regular NMR spectrometers. The diluted top and bottom part of the sample is away from the coil and contributes less signal. This dilution procedure amplifies the requirement of expensive deuterated solvent and lowers sensitivity. The present study explores a new way of sample preparation which involves sandwiching a small amount of the deuterated solvent (D₂O) of length 1.8 cm containing the analyte between two non-deuterated solvents (CCl₄ at bottom of length ≈ 1 cm and similarly C₆H₆ at top), which are immiscible with the former using a regular 5 mm o.d. NMR tube in such a way that total length is still 4 cm as demanded by the magnetic field homogeneity considerations. The analyte now being closer to NMR coil dissolved in 1.8 cm solvent, improves sensitivity and reduces deuterated solvent hitherto required. ¹³C and ¹⁵N spectra from such a set-up display two to three-fold higher signal to noise ratio and hence four to eightfold savings in experimental time or faster data collection.</p><br>

A Triple Layer of Immiscible Solvents for NMR Sample Preparation: Enhanced Sensitivity and Reduced Deuterated Solvent for Observation of Heteronuclei

<p>Organic chemistry labs routinely perform NMR in a standard 5 mm NMR tube. NMR sample is prepared by filling the lowermost 4 cm length of a regular 5 mm 0.d. tube that holds approximately 0.55 ml of a deuterated solvent. This is actually a sample dilution procedure as the signal mainly comes from the central part, i.e. 1.8 cm length sample that fits the typical coil length of 1.8 cm in regular NMR spectrometers. The diluted top and bottom part of the sample is away from the coil and contributes less signal. This dilution procedure amplifies the requirement of expensive deuterated solvent and lowers sensitivity. The present study explores a new way of sample preparation which involves sandwiching a small amount of the deuterated solvent (D₂O) of length 1.8 cm containing the analyte between two non-deuterated solvents (CCl₄ at bottom of length ≈ 1 cm and similarly C₆H₆ at top), which are immiscible with the former using a regular 5 mm o.d. NMR tube in such a way that total length is still 4 cm as demanded by the magnetic field homogeneity considerations. The analyte now being closer to NMR coil dissolved in 1.8 cm solvent, improves sensitivity and reduces deuterated solvent hitherto required. ¹³C and ¹⁵N spectra from such a set-up display two to three-fold higher signal to noise ratio and hence four to eightfold savings in experimental time or faster data collection.</p><br>