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Green Synthesized Carbon-Based Nanomaterials: Applications and Future Developments
Published in Shrikaant Kulkarni, Ann Rose Abraham, A. K. Haghi, Renewable Materials and Green Technology Products, 2021
Anu Rose Chacko, Neena John Plathanam, Binila K Korah, Thomas Abraham, Beena Mathew
The different applications of CND in quantum sensing include magnetic protein detection, magnetic resonance imaging (MRI), near field coupling, and nanoscale thermometer. The magnetic protein ferritin affects the electron spin resonance of near field coupled NV centers. Thus, the use of CND as a magnetic sensor for the successful determination of ferritin concentrations.145 The optical polarization of spins of electrons in NV centers and transferring polarization to 3C nuclei leads to hyperpolariza-tion. This offers enhanced sensitivity and high nuclear spin lifetime results in the application of MRI.146 The specific arrangement of molecules and nanoparticles by DNA origami opened a new way in near field coupling investigation. The conjugation of neutravidin with CND and biotin-labeled oligonucleotide was investigated. The spin resonance property of NV and estimation of DNA origami in the nanolevel and distance-dependent coupling of CND highlighted to manage the NV base quantum devices in future applications of near field coupling and quantum sensing. To monitor local temperature change, the development of CND in the nanoscale thermometer was investigated. The pronounced sensitivity, sturdy reaction to the local environment, and high range detection enhanced the need of nanoscale thermometer.147
Crude Oil and Asphaltene Characterization
Published in Francisco M. Vargas, Mohammad Tavakkoli, Asphaltene Deposition, 2018
R. Doherty *, S. Rezaee *, S. Enayat, M. Tavakkoli, F. M. Vargas
Nuclear magnetic resonance (NMR) is a property of the nucleus of an atom, related to what is known as nuclear spin (the nucleus acting like a miniature bar magnet). When the atomic nucleus spins, it generates a magnetic field, and if an external magnetic field is present, the nucleus aligns either with or against the field of the external magnet. The difference between the energy of the aligned and the misaligned nuclei depends on the applied magnetic field; the greater the strength of the magnetic field, the larger the energy difference. If radio waves are applied, the nuclei in the lower energy state absorb the energy and jump to the higher energy state and then, they undergo relaxation and return to the original energy state. When relaxing, electromagnetic signals are emitted at determined frequencies that depend on the difference in energy. These signals are recorded on a graph of intensity versus signal frequency (or chemical shift, in ppm). The most common nuclei analyzed by NMR are 1H, 13C, 15N, and 31P; however, only 1H and 13C are used in asphaltene characterization. Figure 2.9 shows the NMR spectra of C5+ asphaltenes of crude oil S6.
Magnetic Resonance Imaging
Published in Kayvan Najarian, Robert Splinter, Biomedical Signal and Image Processing, 2016
Kayvan Najarian, Robert Splinter
Magnetic resonance imaging (MRI) is an imaging technique that makes use of the phenomenon of nuclear spin resonance. The principle idea of MRI is based on the fact that when a magnet is exposed to an external magnetic field, it tries to orient itself to align with the external magnetic field. This idea explains that the spin axis of the protons in the atoms of the biological tissues exposed to the MRI’s large magnetic field will orient itself in a direction parallel to the magnetic field lines. In the majority of cases, the magnetic resonance is tuned to imaging of the magnetic spin of the hydrogen nuclei in water molecules Measuring the spin information for a group of molecules provides the means of creating an MR image of the biological tissue under study.
Perspective on long-lived nuclear spin states
Published in Molecular Physics, 2020
Nuclear spin relaxation is of prime importance in nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI). The relaxation properties of nuclear spins, including longitudinal and transverse relaxation rate constants, and cross-relaxation rate constants, provide a rich source of information on molecular structure and dynamics, as well as on microscopic environments. Relaxation times are also a measure of the ‘memory’ of a nuclear spin system. In some contexts, short relaxation times are beneficial in order to, e.g. run closely spaced consecutive scans without inter-scan interferences. In many cases, however, long relaxation times are desirable, to extend the timescales during which information may be stored with magnetic resonance. For an ensemble of uncoupled spins, the return to equilibrium of longitudinal magnetisation is the slowest relaxation process. As a result, the longitudinal relaxation time constant is often considered as the upper limit of the memory time of a spin system.