188,932 research outputs found
Nuclear Magnetic Resonance Imaging of Li-ion Battery
Nuclear magnetic resonance (NMR) imaging has high sensitivity to proton (1H) and lithium (7Li). It is a useful measurement for electrolyte in Li-ion battery. 1H NMR images of lithium ion battery which is composed of LiMn2O4 / LiClO4 + propylene carbonate (PC) / Li-metal have been studied. 1H NMR images of electrolyte near cathode material (LiMn2O4) showed anomalous intensity distribution, which was quite inhomogeneous. From NMR images as a function of repetition time (TR), it was concluded that the anomalous intensity distribution was not due to change of relaxation time but an indirect (spatial) para-magnetization effect from cathode material. The paramagnetization induced by high magnetic field distorts linearity of magnetic gradient field, leading to apparent intensity variance. This functional image is an easy diagnostic measurement for magnetization of cathode material, which allows the possibility to check uniformity of cathode material and change of magnetization under electrochemical process. Received: 7 October 2010; Revised: 1 December 2010; Accepted: 17 December 201
Nuclear magnetic resonance cryoporometry
Nuclear Magnetic Resonance (NMR) cryoporometry is a technique for non-destructively determining pore size distributions in porous media through the observation of the depressed melting point of a confined liquid. It is suitable for measuring pore diameters in the range 2 nm-1 mu m, depending on the absorbate. Whilst NMR cryoporometry is a perturbative measurement, the results are independent of spin interactions at the pore surface and so can offer direct measurements of pore volume as a function of pore diameter. Pore size distributions obtained with NMR cryoporometry have been shown to compare favourably with those from other methods such as gas adsorption, DSC thermoporosimetry, and SANS. The applications of NMR cryoporometry include studies of silica gels, bones, cements, rocks and many other porous materials. It is also possible to adapt the basic experiment to provide structural resolution in spatially-dependent pore size distributions, or behavioural information about the confined liquid
Wide-range nuclear magnetic resonance detector
Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments
Microstructure, vacancies and moments of nuclear magnetic resonance of hydrogenated amorphous silicon
Recent experiments on hydrogenated amorphous silicon using infrared
absorption spectroscopy have indicated the presence of mono- and divacancy in
samples for concentration of up to 14\% hydrogen. Motivated by this
observation, we study the microstructure of hydrogen in two model networks of
hydrogen-rich amorphous silicon with particular emphasis on the nature of the
distribution (of hydrogen), the presence of defects, and the characteristic
features of the nuclear magnetic resonance spectra at low and high
concentration of hydrogen. Our study reveals the presence of vacancies, which
are the built-in features of the model networks. The study also confirms the
presence of various hydride configurations in the networks that include from
silicon monohydrides and dihydrides to open chain-like structures, which have
been observed in the infrared and nuclear magnetic resonance experiments. The
broad and the narrow line widths of the nuclear magnetic resonance spectra are
calculated from a knowledge of the distribution of spins (hydrogen) in the
networks.Comment: 15 pages, 16 figure
Quantum Computing and Nuclear Magnetic Resonance
Quantum information processing is the use of inherently quantum mechanical
phenomena to perform information processing tasks that cannot be achieved using
conventional classical information technologies. One famous example is quantum
computing, which would permit calculations to be performed that are beyond the
reach of any conceivable conventional computer. Initially it appeared that
actually building a quantum computer would be extremely difficult, but in the
last few years there has been an explosion of interest in the use of techniques
adapted from conventional liquid state nuclear magnetic resonance (NMR)
experiments to build small quantum computers. After a brief introduction to
quantum computing I will review the current state of the art, describe some of
the topics of current interest, and assess the long term contribution of NMR
studies to the eventual implementation of practical quantum computers capable
of solving real computational problems.Comment: 8 pages pdf including 6 figures. Perspectives article commissioned by
PhysChemCom
Near-zero-field nuclear magnetic resonance
We investigate nuclear magnetic resonance (NMR) in near-zero-field, where the
Zeeman interaction can be treated as a perturbation to the electron mediated
scalar interaction (J-coupling). This is in stark contrast to the high field
case, where heteronuclear J-couplings are normally treated as a small
perturbation. We show that the presence of very small magnetic fields results
in splitting of the zero-field NMR lines, imparting considerable additional
information to the pure zero-field spectra. Experimental results are in good
agreement with first-order perturbation theory and with full numerical
simulation when perturbation theory breaks down. We present simple rules for
understanding the splitting patterns in near-zero-field NMR, which can be
applied to molecules with non-trivial spectra.Comment: 5 pages, 5 figure
Projective measurement in nuclear magnetic resonance
It is demonstrated that nuclear magnetic resonance experiments using
pseudopure spin states can give possible outcomes of projective quantum
measurement and probabilities of such outcomes. The physical system is a
cluster of six dipolar-coupled nuclear spins of benzene in a liquid-crystalline
matrix. For this system with the maximum total spin S=3, the results of
measuring are presented for the cases when the state of the system is one
of the eigenstates of .Comment: 9 pages incluing 3 figure
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