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Recent advances in the analysis of coal-derived products
1979-09-01
Recent developments in some of the most important fields of the analytical chemistry of coal and its derivatives are critically reviewed: separation methods; in particular gel-permeation, high-pressure liquid and gas chromatography, C-13 nuclear magnetic resonance spectroscopy, u.v. visible spectrophotometry, fluorimetry and phosphorimetry. Progress in statistical structural analysis, based on both chemical reactions and physical methods, usually n.m.r., is also comprehensively reported.
2007-01-01
Glycogen-accumulating organisms (GAOs) are found in enhanced biological phosphorus removal systems where they compete with polyphosphate-accumulating organisms for external carbon substrates. C-13 nuclear magnetic resonance (C-13-NMR) was used to elucidate the metabolic pathways operating in an enriched GAO culture dominated by two known GAOs (81.2%). The experiments consisted of adding C-13-acetate (labelled on position 1 or 2) to the culture under anaerobic conditions, and operating the culture through a cycle consisting of an anaerobic, an aerobic and a further anaerobic phase. The carbon transformations over the cycle were monitored using in vivo(13)C-NMR. The two-carbon moieties in hydroxybutyrate and hydroxyvalerate were derived from acetate, while the propionyl precursor of hydroxyvalerate was primarily derived from glycogen, with only a small fraction originating from acetate. Comparison of the labelling patterns in hydroxyvalerate at the end of the first and the second anaerobic periods in pulse experiments with 2-C-13-acetate showed that the Entner-Doudoroff (ED) pathway was used for the breakdown of glycogen. This conclusion was further supported by the labelling pattern on glycogen observed in the pulse experiments with 1-C-13-acetate, which can only be explained by the operation of ED with recycling of pyruvate and glyceraldehyde 3-phosphate via gluconeogenesis. The activity of the ED pathway for glycogen degradation by GAOs is demonstrated here for the first time. In addition, the decarboxylating part of the tricarboxylic acid cycle was confirmed to operate also under anaerobic conditions. Publisher: Blackwell Publishing Coverage: 2007-01-01T00:00:00Z
Toward microtesla MRI of hyperpolarized carbon-13 for real-time metabolic imaging
2009-11-09
Hyperpolarization of carbon-13 is a promising technique that has enabled MR angiography, perfusion mapping, and real-time metabolic imaging of C-13 labeled organic substances with unprecedented signal-to-noise levels. Because the hyperpolarization is performed outside an MRI scanner (using a special NMR-style hyperpolarizer), high magnetic fields of conventional MRI systems offer little advantage in terms of achievable C-13 polarization. Here we propose an ultimate low-field MRI scanner for imaging hyperpolarized C-13. It uses only microtesla-range magnetic fields and employs SQUID (superconducting quantum interference device) sensors for broadband reception of MRI signals. We present the first images acquired by SQUID-based microtesla MRI with dynamic nuclear polarization (Overhauser enhancement). We also report the first NMR spectra of C-13 at microtesla fields, including spectra of metabolically relevant sodium pyruvate, bicarbonate, and alanine. Our results demonstrate feasibility and potential of the proposed imaging approach.
1997-01-01
Cell-wall polysaccharides from six species of red algae of the genus Callophycus were mainly galactans comprised predominantly of galactose (Gal) and 3,6-anhydrogalactose (AnGal), and were rich in pyruvate and sulfate. The Fourier Transform Infrared (FTIR) spectra of the polysaccharides superficially resembled that of alpha-carrageenan (composed of the repeating disaccharide carrabiose 2-sulfate), with major bands of absorption indicative of if-linked AnGal, axial 2-sulfate on 4-linked AnGal, and unsulfated, 3-linked Gal. The FTIR spectra of solutions of Callophycus polysaccharides in D2O-phosphate buffer displayed absorption, corresponding to the carboxylate anion of the pyruvate acetal substituent. Methylation analysis showed that 3,4,6-linked Galp (interpreted as 4,6-pyruvated, 3-linked Galp) and 2,4-linked AnGalp (interpreted as 4-linked AnGalp 2-sulfate) were the dominant links, together with significant quantities of 3-linked Galp. Proton-decoupled C-13 nuclear magnetic resonance (NMR) spectroscopy showed the polysaccharides to be composed predominantly of pyruvated carrageenans. The C-13 NMR spectra were completely assigned by a J-modulated spin-echo pulse sequence and 2D experiments employing gradient Heteronuclear Multiple Bond Correlation (HMBC), C-13/H-1 Heteronuclear Multiple Quantum Coherence (HMQC), and HMQC Total Correlation Spectroscopy (HMQC-TOCSY). The Callophycus galactans thus consist predominantly of the novel repeating disaccharide 4',6'-O-(1-carboxyethylidene)carrabiose 2-sulfate and minor amounts of the alpha-carrageenan repeating unit (carrabiose 2-sulfate), and other structural variations. (C) 1997 Elsevier Science Ltd. Coverage: 1997-01-01T00:00:00Z
2001-01-01
For a safe operation of nuclear power plants and new reactors, physical radiation effects on materials for reactor vessels must be studied, while neutron radiation causes displacement damage in the metal lattice (radiation hardening). Neutron reactions with alloy element produce other isotopes with different properties. Metallographical and fractographical properties of metals (AISI316L, A508c13) for nuclear applications are described
2010-01-01
Methods of measuring the radii of unstable nuclear states based on use of diffractive and rainbow scattering were developed and applied for search of the signatures of alpha-particle condensation effects in some states of 12C, 13C and 11B near the alpha -thresholds. The enhancement of the nuclei radii by factor 1.2 - 1.3 relatively those in the ground states were observed
Perspectives of abdominal nuclear magnetic resonance diagnostics
1983-01-01
The author reports about the physical foundations and the imaging techniques of nuclear magnetic resonance. Further, the results of abdominal nuclear magnetic resonance are discussed by means of examples of images of the stomach-colon aorta, spleen, spleen vessels and kidneys.
Shell effects in nuclear magnetization
2000-08-01
The magnetization of nuclei in strong magnetic fields associated with magnetars' is considered within the shell model. It is demonstrated that the magnetic field gives rise to a phase-shift of the shell-oscillations in nuclear masses shifting significantly the nuclear magic numbers of the iron region towards smaller mass numbers. Shell-effects are found to result in anomalies of the nuclear magnetization. Such anomalies resemble the behavior associated with a phase transition. (author)
Nuclear magnetism in enriched 195Pt metal
2009-01-01
Platinum represents both a most interesting system for study nuclear magnetism and the only standard sample of NMR thermometry at ultra-low temperatures. Magnetization, specific heat and nuclear magnetic resonance measurements were performed in a 93.52% enriched 195Pt metal with an iron concentration of 105 ppm. Both nuclear magnetic resonance and relaxation are strongly influenced by the 3d-impurities
Theory of nuclear magnetic relaxation
A theory of nuclear magnetic interaction is based on the study of the stochastic rotation operator. The theory is applied explicitly to relaxation by anisotropic chemical shift and to spin-rotational ...
A potential nuclear magnetic resonance imaging approach for noncontact temperature measurement
It is proposed that in a nuclear magnetic resonance (NMR) imaging experiment that it should be possible to measure temperature through an extended volume. The basis for such a measurement would depend ...
1975-01-01
The following principal methods of nuclear polarization measurement are presented: methods using nuclear magnetic resonance techniques, the method of internal magnetic field and methods using nuclear scattering asymmetries. The theory, some experimental problems of each method as well as a comparison between them are developed. Special attention is given to the measurement of nuclear polarization of polarized targets for nuclear experiments at low energies.
2008-12-15
The major objective of the present study was to evaluate the correlation between structural nature of humic acids (HAs) and sorption affinity of organic compounds with varied polarity. We compared the sorption behavior of three aromatic compounds-nonpolar phenanthrene (PHEN) and 1,2,4,5-tetrachlorobenzene (TeCB) and highly polar 2,4-dichlorophenol (DCP)-to a solid-phase coal humic acid (CHA) and a soil humic acid (SHA) suspended in aqueous solution. The structural nature of HAs was characterized using elemental analysis, ultraviolet absorbance, diffusive reflectance Fourier-transform infrared, and solid-state C-13 nuclear magnetic resonance. The two tested HAs have very different structural properties: CHA consists primarily of poly(methylene)-rich aliphatics with high aromatic content and some COO/N-C=O but low polarity, while SHA consists of young materials of lignin, carbohydrates, and peptides with high polarity. In response to the structural heterogeneity of HAs, sorption of nonpolar and more hydrophobic solutes (PHEN, TeCB) to CHA is much greater than that to SHA because of the predominance of hydrophobic effects; however, disparities in sorption affinity between the two HAs become smaller for polar and less hydrophobic DCP because of the major role played by polar interactions. The influence of pH on the sorption of different solutes to the two HAs was also discussed. The results of the present work highlight the importance of structural heterogeneity of both solutes and HAs in the sorption process.
Humics and radionuclide migration
1988-01-01
Humic materials occur throughout the ecosphere in soils and waters, even in deep anoxic underground systems. The spectrum of molecula weights, the nature of the carbon skeleton and the types, positions and relative numbers of functional groups vary widely, in part depending on the origin and age of the humic material. Acid-base titration, C-13 CP/MAS solid-state nuclear magnetic resonance and ultrafiltration serve to define major operational characteristics of these materials. Humic materials sorb to surfaces and particulate matter in waters and can form colloids themselves. The structures and other general properties of humic substances are discussed briefly. Of importance in the migration of radionuclides in geological media is the strong complexing and redox interactions of humic materials to metal ions. The polyelectrolyte nature of humic molecules leads to very strong complexing which increases in strength with the increasing degree of ionization of the carboxylate groups. In addition, metal ions can be reduced to lower states; e.g., Pu(VI) to Pu(IV). Some unique problems are encountered in measuring the metal binding and/or redox by humic materials. However, such data is important as humic material can have significant effects on metal ion speciation and behavior in geologic systems even at 0.1 ppm levels. Measurements of actinide-humate interactions and their possible consequences on actinide migration are reviewed.
2009-05-07
The description of the nuclear magnetic resonance magnetization dynamics in the presence of long-range dipolar interactions, which is based upon approximate solutions of Bloch–Torrey equations...Full Text Available
Nuclear magnetic relaxation dispersion
1988-01-01
Nuclear magnetic relaxation dispersion (NMRD) is the set of data representing the dependence of nuclear spin-lattice relaxation rates on the strength of the d.c. magnetic field used in NMR imaging. The field dependence of the nuclear spin relaxation provides a clear picture of the several factors that may contribute to or dominate relaxation in paramagnetic systems. Without this information, it is difficult to develop rational strategies for control of nuclear spin relaxation. (U.K.).
A study on the impediment of thickness diminution of carbon steel tube using applied magnetic field
2002-03-15
Carbon steel pipe is used as a pipe laying for the cooling water of nuclear reactor. In order to examine the diminution of steel thickness, the magnetic field permeability of applicable permanent magnets was simulated by computer. The susceptibility of the permanent magnets according to the temperature was measured to investigate the applicability of permanent magnets at the cooling water temperature of nuclear power plant. The structure and magnetic properties of carbon steel tube were observed regarding to the existence of oxidized layer.
A study on the impediment of thickness diminution of carbon steel tube using applied magnetic field
2002-01-01
Carbon steel pipe is used as a pipe laying for the cooling water of nuclear reactor. In order to examine the diminution of steel thickness, the magnetic field permeability of applicable permanent magnets was simulated by computer. The susceptibility of the permanent magnets according to the temperature was measured to investigate the applicability of permanent magnets at the cooling water temperature of nuclear power plant. The structure and magnetic properties of carbon steel tube were observed regarding to the existence of oxidized layer
Magnetism and magnetic measurement techniques for ageing management in nuclear power plants
2010-01-01
The ageing management in nuclear power plants is an important issue in Japan due to the increase in the number of ageing plants. This paper briefly describes the current situation with nuclear power plants in Japan. Then, categories of degradation events in nuclear power plants are explained. Several techniques of inspection developed by utilities and the vendors of nuclear power plants are also introduced followed by a description of advanced inspections based on magnetism and magnetic measurements to enhance the ageing management in nuclear power plants. (author)
2010-01-01
Two (di)haploids (2n=2x=24) and nine tetraploids (2n=4x=48) obtained from Solanum tuberosum through anther culture were characterized for nDNA variation, phenotypic variation and nuclear microsatellite polymorphism. Androgenic (di)haploids were also characterized for late blight resistance. The (di)haploid C-13 was derived from Indian tetraploid potato cv. Kufri Chipsona-2, while D4 from TPS (true potato seed) parental line JTH/C-107, which is an interspecific hybrid between Indian tetraploid cv. Kufri Jyoti and diploid (2n=2x=24) cultivated species S. phureja Juz. & Buk. IVP-35. C-13 and D4 (both male-fertile) could be distinguished from their corresponding tetraploid anther donors based on plant height, shoot number, terminal leaflet length and width, leaf ratio, ...
1993-12-31
The discovery of branched sugars as the constituents of biologically active compounds gave raise to the development of several methodologies to their chemical preparation therefore turning into a very interesting field to the organic chemistry synthesis. One of the possibilities of the utilization of such sugars is the synthesis of chiral backbones to the preparation of a branched amino-sugars. This work is concerned to the determination of C-2 in such compounds by NMR 6 refs., 3 figs.
21 CFR 892.1000 - Magnetic resonance diagnostic device.
...Identification. A magnetic resonance diagnostic device is intended...spatial distribution and/or magnetic resonance spectra which reflect frequency...distribution of nuclei exhibiting nuclear magnetic resonance. Other physical...
Polarized neutrons and their applications
The role of polarized neutrons in the study of magnetic and nonmagnetic materials is discussed. magnetic structure, spin density, nuclear magnetism and spin dynamics are listed as magnetic properties which may be accessed by polarized neutrons. Low dimensional magnets, disordered magnetic systems, surface magnetism are discussed as well as topography and depolarization. Polarization techniques are discussed for both study state and pulsed modes. 4 refs. (WRF)
Search for magnetic monopoles with nuclear track detectors
This paper describes an experimental search for GUT magnetic monopoles in the MACRO experiment using the nuclear track subdetector CR39. After discussing the working principle, the charge resolution and the calibration of the detector, the experimental procedure for searching for magnetic monopoles is described. Since no candidates were found, the upper flux limits obtained by the MACRO CR39 used as a "stand alone detector" for magnetic monopoles of different magnetic charges are presented.
High-field nuclear magnetic resonance with a newly designed hybrid magnet system
2009-01-01
Nuclear magnetic resonance (NMR) measurements using a newly designed hybrid magnet system installed at the National Institute for Materials Science were performed up to 28 T. A modified resistive insert magnet improved the field homogeneity of the hybrid magnet from 186 ppm/+-5 mm to 16 ppm/+-5 mm along the z-axis. Reconstruction of the power source for the resistive magnet suppressed the field instability from 30 to 3 ppmrms. These improvements enable us to obtain an NMR spectrum with narrower linewidth. (author)
Potential Applications of Nuclear Resonance Fluorescence
2009-01-01
Nuclear resonance fluorescence (NRF) is a photon-based active interrogation approach that provides isotope-specific signatures that can be used to detect and characterize samples. Photon energies are in the range of a few MeV, so that penetration through significant material is possible. Unlike other active interrogation techniques that are based on inducing fission, NRF is sensitive to a wide range of isotopes: for example 11B, 12C, 13C, 14N, 16O, 27Al, 208Pb, 235U, 238U and 239Pu just to name a few. NRF is most likely to outperform existing technologies for applications requiring isotopic information of sealed samples. Pacific Northwest National Laboratory is conducting a review of potential applications that could be addressed by NRF ...
Phase transition in warm nuclear matter with alternative derivative coupling models
An analysis is performed of the liquid-gas phase transition of nuclear matter obtained from different versions of scalar derivate coupling suggested by Zimanyi and Moszkowski (ZM) and the results are compared with those obtained from the Walecka model. We present the phase diagram for the models and one of them, the ZM3 model, has the lowest critical temperature T_c=13.6 MeV with the lowest critical density \\rho_c=0.037 fm^{-3} and pressure p_c=0.157 MeV fm^{-3}. These results are in accord with recent observations from energetic heavy-ion collisions, which suggest a small liquid-gas phase region.
Analysis of the magnetic field, force, and torque for two-dimensional Halbach cylinders
2010-01-01
The Halbach cylinder is a construction of permanent magnets used in applications such as nuclear magnetic resonance apparatus, accelerator magnets and magnetic cooling devices. In this paper the analytical expression for the magnetic vector potential, magnetic flux density and magnetic field for a two dimensional Halbach cylinder are derived. The remanent flux density of a Halbach magnet is characterized by the integer p. For a number of applications the force and torque between two concentric Halbach cylinders are important. These quantities are calculated and the force is shown to be zero except for the case where p for the inner magnet is one minus p for the outer magnet. Also the force is shown never to be balancing. The torque is shown to be zero unless the inner magnet p is equal to minus the outer magnet p. Thus there can never be a force and a torque in the same system
Preliminary proton nuclear magnetic resonance (NMR) studies were made to determine the applicability of this technique for the study of interactions between monomeric and polymeric amino acids with monomeric nucleic acid ...
Preliminary proton nuclear magnetic resonance (NMR) studies were made to determine the applicability of this technique for the study of interactions between monomeric and polymeric amino acids with ...
SURFACE NUCLEAR MAGNETIC RESONANCE IMAGING OF WATER CONTENT DISTRIBUTION IN THE SUBSURFACE
The objective of this research is to advance the technology of nuclear magnetic resonance (NMR) for direct measurement of water content distributions in the subsurface. The proof-of-concept of this method has been demonstrated by Russian scientists at the Institute of Chemical Ki...
Nuclear magnetic resonance micro-imaging of the human eye lens
2001-01-01
None Available Publisher: Queensland University of Technology Relation: Moffat, Bradford Armstrong (2001) Nuclear magnetic resonance micro-imaging of the human eye lens. [QUT Thesis] Rights: Copyright Bradford Armstrong Moffat
Cryogenic nuclear magnetic resonance gyroscope
1981-01-01
Advances in the development of an inertial navigation system based on cryogenic nuclear magnetic resonance gyros are reviewed with reference to the basic requirements, laboratory systems, and operational problems. It is shown that an inertial sensor package using superconducting quantum interference devices as detectors will provide adequate sensitivity.
Interactions of the metals cadmium and selenium with various biologically important substrates were studied by nuclear magnetic resonance (NMR) spectroscopy. Cadmium-113 NMR was used for a critical examination of three metalloproteins: concanavalin A, bovine superoxide dismutase ...
A cryogenic nuclear magnetic resonance gyroscope
Advances in the development of an inertial navigation system based on cryogenic nuclear magnetic resonance gyros are reviewed with reference to the basic requirements, laboratory systems, and operational problems. It is shown that an inertial sensor package using superconducting quantum interference devices as detectors will provide adequate sensitivity.
2006-11-26
Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertial-rotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.
Studies of magnetism by nuclear orientation and NMRON
1999-01-01
Low temperature nuclear orientation (NO) and nuclear magnetic resonance on oriented nuclei (NMRON) are used to investigate the magnetic properties of solids, and are especially useful when high sensitivity is required, for example in the study of small or dilute systems. Measurement of the static hyperfine interaction and the nuclear spin-lattice and spin-spin relaxation times T1 and T2 yield information about the electronic magnetization and spin dynamics, respectively. A number of NMRON techniques are available and their application to the study of magnetism will be briefly discussed. In particular, the pulsed technique has been shown to be effective for studying insulators. Recent NO and NMRON measurements, primarily on insulating magnets and magnetic multilayers, will be reviewed. Spins of stable isotopes can also be investigated using ...
Study of magnetic moments of nuclear excited states at TRISTAN
Measurement of the static magnetic dipole moments of nuclear excited states are of interest since they reveal information on nuclear structure not available by other means. A system has been constructed at the TRISTAN separator to measure magnetic dipole moments of excited states in neutron-rich nuclei using the method of perturbed angular correlations (PAC). High magnetic fields are not available through the use of a superconducting magnet. The capability of the TRISTAN system is discussed and the PAC measuring apparatus is described. Final results from recent g factor measurements at TRISTAN on 4/sup +/ states in the N = 82 isotones are discussed in some detail. Studies in progress are briefly outlined.
Quantum mechanics: the key to understanding magnetism
1978-07-14
The treatment of magnetism includes the study prior to the advent of quantum mechanics, the influence of quantum mechanics as the last real key, crystal field theory, relaxation effects and ferromagnetism, and nuclear magnetism. 82 references. (JFP)
Magnetic resonance sees lesions of multiple sclerosis
1985-02-15
The value of nuclear magnetic resonance imaging in the diagnosis and quantitation of the progression of multiple sclerosis is discussed. Magnetic resonance imaging generates images that reflect differential density and velocity of hydrogen nuclei between cerebral gray and white matter, as well as between white matter and pathological lesions of the disease.
Contrast agents in magnetic resonance imaging
1985-05-01
The origin of nuclear magnetic resonance signal is reviewed in this study. Different ways of increasing the contrast in magnetic resonance imaging are presented, especially modifications of tissues relaxation times by the use of paramagnetic ions or nitroxides. The potential of these substances is illustrated by several examples of application in the animal.
Construction of a large superconducting spectrometer magnet
This paper reports on a sector type superconducting spectrometer magnet, SKS, for nuclear physics experiments constructed by Institute for Nuclear Study, University of Tokyo with collaboration from KEK. The central magnetic field is 3 tesla with the magnet gap of 50 cm and the stored energy is estimated at 11.2 MJ. The total weight of the magnet is 280 tons with the iron yoke. Three dimensional magnetic field calculation and the stress analysis have been performed to design the coil and supporting structures. The magnet has a flexible helium transfer line to be movable to measure angular distributions at nuclear physics experiments. To simplify the transfer line, a small-size G-M refrigerator, which is installed on a service port of the helium vessel, is adopted for thermal insulations at 80 K and 20 K in combination with a medium-size refrigerator for cooling the magnet at 4 K.
Construction of a large superconducting spectrometer magnet
1991-03-01
This paper reports on a sector type superconducting spectrometer magnet, SKS, for nuclear physics experiments constructed by Institute for Nuclear Study, University of Tokyo with collaboration from KEK. The central magnetic field is 3 tesla with the magnet gap of 50 cm and the stored energy is estimated at 11.2 MJ. The total weight of the magnet is 280 tons with the iron yoke. Three dimensional magnetic field calculation and the stress analysis have been performed to design the coil and supporting structures. The magnet has a flexible helium transfer line to be movable to measure angular distributions at nuclear physics experiments. To simplify the transfer line, a small-size G-M refrigerator, which is installed on a service port of the helium vessel, is adopted for thermal insulations at 80 K and 20 K in combination with a medium-size refrigerator for cooling the magnet at 4 K.
Nuclear magnetic tomography in the differential diagnosis of liver disease
1985-05-01
In evaluating nuclear magnetic tomography for the diagnosis of liver disease, one must differentiate between circumscribed and diffuse lesions. Nuclear magnetic tomography provides additional information for lesions which are echogenic on ultrasound and can differentiate between metastases, haemangiomas and hamartomas. In diffuse parenchymal disease measurement of relaxation time can differentiate between fatty liver, cirrhosis (alcoholic, primary biliary), haemochromatosis (cirrhotic transformation) and hepatoma. NMR spectroscopy is a method for the future.
Nature of Planetary Matter and Magnetic Field Generation in the Solar System
2009-03-27
Understanding the nature of the matter comprising the Solar System is crucial for understanding the mechanism that generates the Earth's geomagnetic field and the magnetic fields of other planets and satellites. The commonality in the Solar System of matter like that of the inside of the Earth, together with common nuclear reactor operating conditions,forms the basis for generalizing the author's concept of nuclear geomagnetic field generation to planetary magnetic field generation by natural planetocentric nuclear fission reactors.
Analysis of the magnetic field, force, and torque for two-dimensional Halbach cylinders
2010-01-01
The Halbach cylinder is a construction of permanent magnets used in applications such as nuclear magnetic resonance apparatus, accelerator magnets and magnetic cooling devices. In this paper the analytical expression for the magnetic vector potential, magnetic flux density and magnetic field for a two dimensional Halbach cylinder are derived. The remanent flux density of a Halbach magnet is characterized by the integer p. For a number of applications the force and torque between two concentric Halbach cylinders are important. These quantities are calculated and the force is shown to be zero except for the case where p for the inner magnet is one minus p for the outer magnet. Also the force is shown never to be balancing. The torque is shown to be zero unless the inner magnet p is equal to ...
Nuclear magnetic properties and Gamow-Teller transitions
1984-01-01
An historical review of nuclear magnetic dipole moments, magnetic dipole and Gamow-Teller transitions is given. It is shown that for the magnetic moments of heavy nuclei, the core polarization and the Sachs moments are most important. Taking nuclei with an LS closed shell +- one nucleon, one sees that tensor correlations play an essential role and the effect of ..delta..-hole excitation is small.
Magnetic resonance at Saclay with Anatole Abragam
1994-12-31
Here is the presentation of the works about nuclear magnetism resonance under the direction of Anatole Abragam at the CEA Saclay in the laboratory of Study on magnetic resonance. From the beginning of nuclear magnetic resonance until the collaboration with other laboratories such these ones directed by Carson Jeffries, Nicolaas Bloemberger and P.P. Sorokin, and Erwin Hahn-Sven Hartmann.
Development and applications of NMR (nuclear magnetic resonance) in low fields and zero field
This dissertation is about nuclear magnetic resonance (NMR) spectroscopy in the absence of applied magnetic fields. NMR is usually done in large magnetic fields, often as large as can be practically attained. The motivation for going the opposite way, toward zero field, is that for certain types of materials, particularly powdered or polycrystalline solids, the NMR spectra in zero field are easier to interpret than those obtained in high field. 92 refs., 60 figs., 1 tab.
Development and applications of NMR (nuclear magnetic resonance) in low fields and zero field
1987-05-01
This dissertation is about nuclear magnetic resonance (NMR) spectroscopy in the absence of applied magnetic fields. NMR is usually done in large magnetic fields, often as large as can be practically attained. The motivation for going the opposite way, toward zero field, is that for certain types of materials, particularly powdered or polycrystalline solids, the NMR spectra in zero field are easier to interpret than those obtained in high field. 92 refs., 60 figs., 1 tab.
Detection of nuclear magnetic resonance with an anisotropic magnetoresistive sensor
2007-10-15
We report detection of nuclear magnetic resonance (NMR) using an anisotropic magnetoresistive (AMR) sensor. A ``remote-detection'' arrangement was used, in which protons in flowing water were pre-polarized in the field of a superconducting NMR magnet, adiabatically inverted, and subsequently detected with an AMR sensor situated downstream from the magnet and the adiabatic inverter. AMR sensing is well suited for NMR detection in microfluidic ``lab-on-a-chip'' applications.
Development of magnetic chromatography to sort polydisperse nanoparticles in ferrofluids
2010-01-01
Whatever the strategy of synthesis, nanoparticles in magnetic fluids commonly feature a broad size distribution. However, the presence of several size populations in ferrofluids is often problematic because of the close relationship between the efficiency of the nanoparticles and their physicochemical properties. In this work, a magnetic size sorting procedure is developed in order to reduce this polydispersity, using the magnetic properties of the iron oxide nanoparticles. This magnetic sorting with an adjustable magnetic field allows isolation of the small superparamagnetic particles as well as the larger particles. Magnetometry, nuclear magnetic relaxation dispersion profiles and transmission electron microscopy were successfully used to check the efficiency of the magnetic sorting proc...
A large 12C/13C isotopic ratio in M82 and NGC253
2010-06-29
To derive carbon isotopic ratios from optically thin tracers in the central regions of the starburst galaxies M82 and NGC253. We present high sensitivity observations of CCH and two of its 13C isotopologues, C13CH and 13CCH, as well as the optically thin emission from C18O and 13C18O. We assume the column density ratio between isotopologues is representative of the 12C13C isotopic ratio. From CCH, lower limits to the 12C/13C isotopic ratio of 138 in M82, and 81 in NGC253, are derived. Lower limits to the 12C/13C ratios from CO isotopologues support these. 13C18O is tentatively detected in NGC253, which is the first reported detection in the extragalactic ISM. Based on these limits, we infer ratios of 16O/18O>350 and >300 in M82 and NGC253, respectively, and 32S/34S>16 in NGC253. and the H2 column density determination through the optically thin tracers 13CO and C18O. The derived CCH fractional abundances toward these galaxies of <~1.1\\times10^-8 are in good agreement with those of molecular clouds in the Galactic disk. Our lower limits to the 12C/13C ratio from CCH are a factor of 2-3 larger than previous limits. The results are discussed in the context of molecular and nucleo-chemical evolution. The large 12C/13C isotopic ratio of the molecular ISM in these starburst galaxies suggest that the gas has been recently accreted toward their nuclear regions.
Nuclear magnetic resonance imaging
1987-05-13
In a nuclear magnetic resonance imaging method, the production of magnetic resonance signals in a part of a body being examined outside a specific region of the body being imaged is prevented by placing magnetic material adjacent that part of the body so as to distort in that part a magnetic field applied to the body during imaging. The magnetic material is suitably in the form of particles distributed in a flexible support member, for example a ferrofluid within plastics ducts in a soft textile fabric. By obtaining signals only from a specific region, the resolution within that region may be increased without extending the imaging time or producing aliasing, e.g. using a two dimensional Fourier transform technique.
Nuclear magnetic resonance imaging
1987-01-01
In a nuclear magnetic resonance imaging method, the production of magnetic resonance signals in a part of a body being examined outside a specific region of the body being imaged is prevented by placing magnetic material adjacent that part of the body so as to distort in that part a magnetic field applied to the body during imaging. The magnetic material is suitably in the form of particles distributed in a flexible support member, for example a ferrofluid within plastics ducts in a soft textile fabric. By obtaining signals only from a specific region, the resolution within that region may be increased without extending the imaging time or producing aliasing, e.g. using a two dimensional Fourier transform technique. (author)
Recovery of nuclear magnetization under extreme inhomogeneous broadening
1996-12-01
A quantitative model is presented for the transient recovery of nuclear magnetization under conditions where nuclear spin dipolar relaxation to dilute relaxation centers proceeds without the intermediary of nuclear spin diffusion. The model is developed for rigid arrays in three, two, and one dimensions. Comparison with experimental results yields measures of effective relaxation rates and relaxation center concentrations. {copyright} {ital 1996 The American Physical Society.}
Recovery of nuclear magnetization under extreme inhomogeneous broadening
1996-01-01
A quantitative model is presented for the transient recovery of nuclear magnetization under conditions where nuclear spin dipolar relaxation to dilute relaxation centers proceeds without the intermediary of nuclear spin diffusion. The model is developed for rigid arrays in three, two, and one dimensions. Comparison with experimental results yields measures of effective relaxation rates and relaxation center concentrations. copyright 1996 The American Physical Society
Synthesis of colchicine and isocolchicine labelled with carbon-11 or carbon-13
1995-01-01
The syntheses of isotopically labelled (-)-10-[11C/13C]-colchicine and (-)-9-[11C/13C]-isocolchicine have been achieved from the reaction of (-)desmethylcolchicine with [11C/13C]-iodomethane. The radiolabelled compounds, (-)-10-[11C]-colchicine (11C-n-colchicine) and (-)-9-[11C]-isocolchicine (11C-i-colchicine), were isolated by reversed phase HPLC. The total synthesis time was approximately 60 minutes for both radiolabelled compounds with an average specific activity of 240 mCi/mumol calculated to EOB. Utilizing a similar synthetic strategy, we also reported the synthesis of milligram quantities of the carbon-13 enriched compounds and the magnetic resonance signal assignment for ...
2010-01-01
We operate a new NEC 250 kV single-stage accelerator mass spectrometer (SSAMS) next to our established 5 MV tandem. This permits good comparison of 14C-AMS and challenges SSAMS performance. Initial SSAMS ion-optical deficiencies have been addressed by shimming the injection magnet and 3 per mille 14C/13C measurement with background limited by sample chemistry is routine. Higher-precision analysis is also achievable. A problematic measurement interference remains, however. The small spectrometer was procured to add measurement capacity, and for experiments with positive ions, but is now the preferred instrument for both convenience and measurement quality
1995-10-01
Physics of plasma involves scales of time so different that approximate models will be always needed to treat specific problems. The Darwin model is nearer to the Maxwell equations than the quasi-static model and allows to get rid of the Courant-Friedrichs-Levy condition on the time step. This model has often been used to describe low frequency phenomena in plasma. Its application range is nevertheless limited by numerical problems occurring about the decomposition of magnetic and electrical fields. In this work we propose a method of decomposition which allows to characterize the solution fields of the Darwin model in the case of a connected region but not only a simply-connected region. (A.C.) 13 refs.
Operational Characteristics of a 14-W 140-GHz Gyrotron for Dynamic Nuclear Polarization
2006-06-01
The operating characteristics of a 140-GHz 14-W long pulse gyrotron are presented. The device is being used in dynamic nuclear polarization enhanced nuclear magnetic resonance (DNP/NMR) spectroscopy...Full Text Available
High-Field Dynamic Nuclear Polarization for Solid and Solution Biological NMR
2008-08-01
Dynamic nuclear polarization (DNP) results in a substantial nuclear polarization enhancement through a transfer of the magnetization from electrons to nuclei. Recent years have seen considerable...Full Text Available
Nonlinear dynamics of quantum dot nuclear spins
2006-09-12
We report manifestly nonlinear dependence of quantum dot nuclear spin polarization on applied magnetic fields. Resonant absorption and emission of circularly polarized radiation pumps the resident quantum dot electron spin, which in turn leads to nuclear spin polarization due to hyperfine interaction. We observe that the resulting Overhauser field exhibits hysteresis as a function of the external magnetic field. This hysteresis is a consequence of the feedback of the Overhauser field on the nuclear spin cooling rate. A semi-classical model describing the coupled nuclear and electron spin dynamics successfully explains the observed hysteresis but leaves open questions for the low field behaviour of the nuclear spin polarization.
19F nuclear spin relaxation and spin diffusion effects in the single-ion magnet LiYF4:Ho3+
2008-01-01
Temperature and magnetic field dependences of the 19F nuclear spin-lattice relaxation in a single crystal of LiYF4 doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed non-exponential long time recovery of the nuclear magnetization after saturation at intermediate temperatures is in agreement with predictions of the spin-diffusion theory in a case of the diffusion limited relaxation. At avoided level crossings in the spectrum of electron-nuclear states of Ho3 + ions, rates of nuclear spin-lattice relaxation increase due to quasi-resonant energy exchange between nuclei and paramagnetic ions in contrast to the predominant rol...
2008-07-01
The properties of dephasing and the resulting relaxation of the magnetization are the basic principle on which all magnetic resonance imaging methods are based. The signal obtained from the gyrating spins is essentially determined by the properties of the considered tissue. Especially the susceptibility differences caused by magnetized materials (for example, deoxygenated blood, BOLD-effect) or magnetic nanoparticles are becoming more important for biomedical imaging. In the present work, the influence of such field inhomogeneities on the NMR-signal is analyzed. (orig.)
PhET Simulation: Simplified MRI
This is an interactive simulation on the topic of Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). The user can change the applied magnetic field and the RF signal and observe the effect on magnetic spins. In the NMR mode, the user can choose between different atoms. In the MRI mode, the user can include gradients to the magnetic field and add a tumor to the head being visualized. This is part of a larger collection developed by the Physics Education Technology project (PhET).
PhET Simulation: Simplified MRI
This is an interactive simulation on the topic of Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). The user can change the applied magnetic field and the RF signal and observe the effect on magnetic spins. In the NMR mode, the user can choose between different atoms. In the MRI mode, the user can include gradients to the magnetic field and add a tumor to the head being visualized. This is part of a larger collection developed by the Physics Education Technology project (PhET).
Synthesis of alpha-Fe2O3 hexagons and their magnetic properties
2009-01-01
alpha-Fe2O3 hexagons are synthesized by a composite-hydroxide-mediated (CHM) method at temperature of 200 deg. C for 24 h. The X-ray diffraction of the synthesized alpha-Fe2O3 sample demonstrates a hexagonal phase with space group of R3-barc(167) and lattice constants of a = 5.00 A and c = 13.62 A. Scanning electron microscopy shows well dispersed hexagons with an average diameter of 3 mum and a thickness of 300-500 nm. The magnetic properties of the hexagons were also investigated. The plot of magnetization versus temperature (M-T) from 100 to 300 K under an applied field of 1000 Oe indicates that the Morin transition temperature is about 220 K, lower than the normal value (263 K) of bulk alpha-Fe2O3. The hysteresis loop exhibits weak ferromagnetic ...
2007-01-01
The synthesis, structural characterization, and magnetic behavior of a novel one-dimensional azido-bridged manganese(III) complex of formula [Mn(L)2N3] (1) is reported, where HL is the bidentate Schiff base obtained from the condensation of salicylaldehyde with 4-methoxy aniline. Complex 1 crystallizes in the monoclinic system, space group P21/n, with a=11.743(4) A, b=24.986(9) A, c=13.081(5) A, beta=95.387(7)o and Z=2. The complex is of one-dimensional chain structure with single end-to-end azido bridges and the manganese(III) ion has an elongated octahedral geometry. Magnetic studies show that the weak antiferromagnetic interaction is mediated by the single end-to-end azido bridge with the exchange parameter J=-5.84 cm-1. - Graphical abstract: A novel azido-bridged ...
Neutron Fermi Liquids under the presence of a strong magnetic field with effective nuclear forces
2009-04-07
Landau's Fermi Liquid parameters are calculated for non-superfluid pure neutron matter in the presence of a strong magnetic field at zero temperature. The particle-hole interactions in the system, where a net magnetization may be present, are characterized by these parameters in the framework of a multipolar formalism. We use either zero- or finite-range effective nuclear forces to describe the nuclear interaction. Using the obtained Fermi Liquid parameters, the effect of a strong magnetic field on some bulk magnitudes such as isothermal compressibility and spin susceptibility is also investigated.
The Role of Magnetic Fields in Spiral Galaxies
2002-12-12
Interstellar magnetic fields are strong: up to 25 muG in spiral arms and 40 muG in nuclear regions. In the spiral galaxy NGC 6946 the average magnetic energy density exceeds that of the thermal gas. Magnetic fields control the evolution of dense clouds and possibly the global star formation efficiency in galaxies. Gas flows and shocks in spiral arms and bars are modified by magnetic fields. Magnetic forces in star-forming circumnuclear regions are able to drive mass inflow towards the active nucleus. Magnetic fields are essential for the propagation of cosmic rays and the formation of galactic winds and halos.
Dense nuclear matter in a strong magnetic field
We investigate in a relativistic Hartree theory the gross properties of cold symmetric nuclear matter and nuclear matter in beta equilibrium under the influence of strong magnetic fields. If the field strengths are above the critical values for electrons and protons, the respective phase spaces are strongly modified. This results in additional binding of the systems with distinctively softer equations of state compared to the field free cases. For magnetic field $\\sim 10^{20}$ Gauss and beyond, the nuclear matter in beta equilibrium practically converts into a stable proton rich matter.
Magnetic properties of vanadium-oxide nanotubes probed by static magnetization and {51}V NMR
2006-02-05
Measurements of the static magnetic susceptibility and of the nuclear magnetic resonance of multiwalled vanadium-oxide nanotubes are reported. In this nanoscale magnet the structural low-dimensionality and mixed valency of vanadium ions yield a complex temperature dependence of the static magnetization and the nuclear relaxation rates. Analysis of the different contributions to the magnetism allows to identify individual interlayer magnetic sites as well as strongly antiferromagnetically coupled vanadium spins (S = 1/2) in the double layers of the nanotube's wall. In particular, the data give strong indications that in the structurally well-defined vanadium-spin chains in the walls, owing to an inhomogeneous charge distribution, antiferromagnetic dimers and trimers occur. Altogether, about 30% of the vanadium ions are coupled in dimers, exhibiting a spin gap of the order of 700 K, the other ~ 30% comprise individual spins and trimers, whereas the remaining \\~ 40% are nonmagnetic.
Desktop fast-field cycling nuclear magnetic resonance relaxometer
2010-01-01
In this paper a new type of Fast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometer with low power consumption (200W) and cycle to cycle field stability better than 10−4 is described. The new high-permeability magnet was designed to allow for good magnetic field homogeneity and allows for the sample rotation around an axis perpendicular to magnetic field, operating with magnetic fields between 0 and 0.21T. The power supply of the new relaxometer was specially developed in order to have steady state accurate currents and allow for magnetic field switching times less than 3ms. Additional control circuits were developed and included to compensate the Earth magnetic field component parallel to the field axis and to compensate for parasitic currents. The main aspects of th...
Superconductivity and its devices
1981-01-01
Among the more important developments that are discussed are cryotrons, superconducting motors and generators, and high-field magnets. Cryotrons will create faster and more economical computer systems. Superconducting motors and generators will cost much less to build than conventional electric generators and cut fuel consumption. Moreover, high-field magnets are being used to confine plasma in connection with nuclear fusion. Superconductors have a vital role to play in all of these developments. Most importantly, though, are the magnetic properties of superconductivity. Superconducting magnets are an integral part of nuclear fusion. In addition, high-field magnets are necessary in the use of accelerators, which are needed to study the interactions between elementary particles
Superconductivity and its devices
Among the more important developments that are discussed are cryotrons, superconducting motors and generators, and high-field magnets. Cryotrons will create faster and more economical computer systems. Superconducting motors and generators will cost much less to build than conventional electric generators and cut fuel consumption. Moreover, high-field magnets are being used to confine plasma in connection with nuclear fusion. Superconductors have a vital role to play in all of these developments. Most importantly, though, are the magnetic properties of superconductivity. Superconducting magnets are an integral part of nuclear fusion. In addition, high-field magnets are necessary in the use of accelerators, which are needed to study the interactions between elementary particles.
Nuclear and magnetic correlations in a topologically frustrated elemental magnet
1999-11-01
{beta}-Mn is an exchange enhanced paramagnetic metal on the verge of antiferromagnetic order. However, strong spin-fluctuations and topological frustration prevent the formation of static long-range order. We investigate the magnetic properties of the {beta}-MnAl series of alloys in which short-range magnetic order is achieved at low temperature. We extract the short-range nuclear and magnetic correlations using a novel reverse Monte-Carlo procedure. (authors) 4 refs., 3 figs.
Nuclear ground-state spin and magnetic moment of 21Mg
2009-01-01
We present the results of combined laser spectroscopy and nuclear magnetic resonance studies of 21Mg. The nuclear ground-state spin was measured to be I=5/2 with a magnetic moment of mu=-0.983(7)muN. The isoscalar magnetic moment of the mirror pair (21F,21Mg) is evaluated and compared to the extreme single-particle prediction and to nuclear shell-model calculations. We determine an isoscalar spin expectation value of =1.15(2), which is significantly greater than the empirical limit of unity given by the Schmidt values of the magnetic moments. Shell-model calculations taking into account isospin non-conserving effects, are in agreement with our experimental results
Nuclear ground-state spin and magnetic moment of 21Mg
We present the results of combined laser spectroscopy and nuclear magnetic resonance studies of 21Mg. The nuclear ground-state spin was measured to be I=5/2 with a magnetic moment of =0.983(7)N. The isoscalar magnetic moment of the mirror pair is evaluated and compared to the extreme single-particle prediction and to nuclear shell-model calculations. We determine an isoscalar spin expectation value of =1.15(2), which is significantly greater than the empirical limit of unity given by the Schmidt values of the magnetic moments. Shell-model calculations taking into account isospin non-conserving effects, are in agreement with our experimental results.
Nuclear Orientation Studies of Magnetic Materials
2001-01-01
Low temperature nuclear orientation (LTNO) and nuclear magnetic resonance on oriented nuclei (NMRON) can be utilized to investigate the magnetic properties of solids, and are especially useful when high sensitivity is required, for example in the study of small or dilute systems. Spins of stable isotopes can also be studied using NMR thermally detected by NO (NMR-TDNO) of the radioactive nuclei. An effect of nuclear spin coupling in ordered magnets is 'frequency pulling' of the abundant spins, and this has been investigated in the quasi-2-dimensional ferromagnet 54Mn-Mn(COOCH3)2.4H2O by comparing the NMRON of the dilute radioactive nuclei with the NMR-TDNO of the abundant host nuclei. A structure in the spectra is observed that is yet to be explained. Recent LTNO experiments on magnetic multilayers are described. ...
Neutron diffraction investigation of the nuclear and magnetic extinction in MnP
1986-01-01
The absolute values of the reflecting powers rho are measured for the 200 and 2+-tau,0,0 set of magnetic and nuclear reflections in the helimagnetic phase of a good-quality crystal of MnP as a function of its thickness. Severe and very different extinction effects are observed for the magnetic and nuclear reflections (y(magnetic) proportional0.4, y(nuclear) proportional0.02 for the largest thickness). This corresponds to the spectacular result that the magnetic reflecting powers rhosub(+-) are twice as big as the nuclear one rhosub(N), in spite of the fact that the scattering cross sections vertical strokeFsub(+-)vertical stroke/sup 2/ are about ten times smaller than the nuclear vertical strokeFsub(N)vertical stroke/sup 2/. The nuclear results appear consistent with dynamical theory while the magnetic ones are not. They can be explained by Zachariasen's type II secondary extinction model based on the chirality domain pattern. The same measurements were performed in the ferromagnetic phase, yielding y(ferro) approx.=0.03. A model using the relative sizes of the ferromagnetic and chirality domains is presented. (orig./BHO).
Neutron diffraction investigation of the nuclear and magnetic extinction in MnP
1986-01-01
The absolute values of the reflecting powers rho are measured for the 200 and 2+-tau,0,0 set of magnetic and nuclear reflections in the helimagnetic phase of a good-quality crystal of MnP as a function of its thickness. Severe and very different extinction effects are observed for the magnetic and nuclear reflections (y(magnetic) proportional0.4, y(nuclear) proportional0.02 for the largest thickness). This corresponds to the spectacular result that the magnetic reflecting powers rhosub(+-) are twice as big as the nuclear one rhosub(N), in spite of the fact that the scattering cross sections vertical strokeFsub(+-)vertical stroke2 are about ten times smaller than the nuclear vertical strokeFsub(N)vertical stroke2. The nuclear results appear consistent with dynamical theory while the magnetic ones are not. They can be explained by ...
1996-01-01
A series of low temperature nuclear orientation (LTNO) experiments has been initiated to measure accurately ground-state magnetic dipole moments of a sequence of odd-proton antimony isotopes up to the neutron shell closure at {ital N}=82 using the sensitive technique of nuclear magnetic resonance on oriented nuclei (NMR/ON). The main aim of this investigation is to clarify the single-particle+collective core coupling mechanism in the heavy antimony isotopes and its influence on the value of magnetic dipole moment. This paper reports results of precision measurement of the magnetic dipole moments of {sup 127}Sb and {sup 129}Sb. {copyright} {ital 1996 The American Physical Society.}
Apparatus for controlling a nuclear reactor by vertical displacement of a unit absorbing neutrons
1980-12-27
Apparatus is described for controlling a nuclear reactor by vertical displacement of a unit absorbing neutrons, comprising, inside a sealed enclosure in communication with the interior of the reactor, a movable magnetic piece connected to a control shaft which is itself connected to the absorbent unit. This magnetic piece has at least two radial projections. The magnetic piece is displaced by an inductor with at least two pole shoes corresponding to the projections on the magnetic piece and allowing magnetic coupling between the inductor and the magnetic piece. The inductor and its displacement device are disposed outside the sealed enclosure. A control means allows the control shaft to be uncoupled from a member assuring its suspension so as to drop the absorbent unit in the event of emergency shutdown. The apparatus is particularly applicable to control rods of pressurized water nuclear reactors.
2009-09-09
In this paper we study the magnetic susceptibility and other thermodynamic properties of the polarized nuclear matter at finite temperature using the lowest order constrained variational (LOCV) method employing the $AV_{18}$ potential. Our results show a monotonic behavior for the magnetic susceptibility which indicates that the spontaneous transition to the ferromagnetic phase does not occur for this system.
In this paper we study the magnetic susceptibility and other thermodynamic properties of the polarized nuclear matter at finite temperature using the lowest order constrained variational (LOCV) method employing the AV{sub 18} potential. Our results show a monotonic behavior for the magnetic susceptibility which indicates that the spontaneous transition to the ferromagnetic phase does not occur for this system.
TRISTAN research on neutron rich nuclei: Magnetic moments and nuclear structure
The TRISTAN research program is briefly outlined. The discussion then turns to the measurements of magnetic moments of excited states in neutron-rich fission product nuclei using the perturbed angular correlation method. The results for 2/sub 1//sup +/ states are analyzed in light of the systematics of magnetic moments in the A = 70-200 region, and relation to collective nuclear models. 28 refs.
Nuclear magnetic resonance spectroscopy in food applications: a critical appraisal
1998-01-01
Usefulness of Nuclear Magnetic Resonance (NMR) spectroscopy in food applications is presented in this review. Some of the basic concepts of NMR pertaining to one-dimensional and two-dimensional techniques, solid-state NMR and Magnetic Resonance Imaging (MRI) are discussed. Food applications dealt with encompass such diverse areas like nature and state of water in foods, detection and quantitation of important constituents of foods, intact food systems and NMR related to food biology. (author)
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
1992-01-14
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
1991-07-15
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
1991-12-17
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts
1991-07-15
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts
1991-12-17
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts
1992-01-14
The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
Method and apparatus for measuring nuclear magnetic properties
A method for studying the chemical and structural characteristics of materials is disclosed. The method includes placement of a sample material in a high strength polarizing magnetic field to order the sample nuclei. The condition used to order the sample is then removed abruptly and the ordering of the sample allowed to evolve for a time interval. At the end of the time interval, the ordering of the sample is measured by conventional nuclear magnetic resonance techniques. 5 figs.
Materials problems in the design of magnetically confined plasma fusion reactor
From joint meeting of the American Nuclear Societty and the Atomic Industrial Forum and Nuclear Energy Exhibition; San Francisco, California, USA (11 Nov 1973). Materials engineering problems are discussed for the following areas: superconducting magnets, tritium breeding, structural materials, radiation damage, electrical insulating materials, tritium problems, hydrogen diffusion barrier, remote fabrication, thermal insulation, and magnet shield. (MOW)
Nuclear quadrupolar resonance spectrometry; Spectrometrie de resonance quadripolaire nucleaire
1999-09-01
The nuclear quadrupolar resonance spectrometry is a hertzian spectrometry of the radiofrequency domain, that bears some resemblance to the magnetic nuclear resonance but with some specificities. The specificity concerns the quadrupolar coupling: the electrical nature of this coupling gives indications on the electrical charges distribution around the nuclei. This method is based on the radiofrequency transitions observation between the energy levels of the nuclear quadrupolar interactions. The definition and the principles of the quadrupolar nuclear resonance are detailed to develop the applications of the corresponding spectrometry. (A.L.B.)
2003-06-30
An overview is given on the application of lasers in nuclear physics. The review focuses on atomic physics techniques for extracting nuclear properties such as the nuclear spin, the magnetic dipole moment, the spectroscopic quadrupole moment, and changes in charge radii. References are given for the work carried out in this field since 1988. At that time, E.W. Otten prepared an extensive review with a complete compilation of data on properties of nuclear ground and isomeric states, obtained by optical spectroscopy on unstable nuclei.
2003-01-01
An overview is given on the application of lasers in nuclear physics. The review focuses on atomic physics techniques for extracting nuclear properties such as the nuclear spin, the magnetic dipole moment, the spectroscopic quadrupole moment, and the changes of charge radii. References are given for the work performed in this field since 1988. At that time, E.W. Otten prepared an extensive review with a complete compilation of data on properties of nuclear ground and isomeric states, obtained by optical spectroscopy on unstable nuclei. (orig.)
Efficient Dynamic Nuclear Polarization at High Magnetic Fields
2006-11-28
By applying a new technique for dynamic nuclear polarization involving simultaneous excitation of electronic and nuclear transitions, we have enhanced the nuclear polarization of the nitrogen nuclei in 15N@C60 by a factor of 1000 at a fixed temperature of 3 K and a magnetic field of 8.6 T, more than twice the maximum enhancement reported to date. This methodology will allow the initialization of the nuclear qubit in schemes exploiting N@C60 molecules as components of a quantum information processing device.
Projective measurement in nuclear magnetic resonance
2006-05-02
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 $S_X$ are presented for the cases when the state of the system is one of the eigenstates of $S_Z$.
Nuclear reactor reactivity control method
1993-01-01
Boron, tantalum, europium or lithium, which is a neutron absorber, is contained in nuclear reactor coolants as a nuclear reactivity control material, as well as an alloy powder or an amorphous alloy powder having a magnetic property is dispersed, and the amount of the alloy powder dispersed in coolants is rapidly controlled by utilizing the magnetic property. With such procedures, rapid response of the reactor reactivity is improved, as well as the stability is increased and simplification of existent equipments can be expected. (T.M.)
1995-12-31
The development of new drugs from penicillins has induced the study of this substances by nuclear magnetic resonance. Several samples of D(-)-{alpha}-amino-benzyl penicillin were analysed using {sup 13} C NMR techniques in aqueous solution and solid state. Spectral data of this compounds were shown and the results were presented and analysed 7 figs., 4 tabs.
1982-01-01
The renormalization group techniques developed by Wilson for the Kondo problem are applied, for the first time, to the calculation of nuclear spin relaxation rates in dilute magnetic alloys. A procedure that calculates the longitudinal relaxation time T1 over the entire temperature range 0 0. A numerical approach, capable of calculating T1 at finite temperatures, is ...
2010-05-28
Pulsars are believed to be magnetized neutron stars. Their surface magnetic field ranges from $10^8$ to $10^{12}$ G. On the other hand, the magnetars have surface magnetic field $10^{14}-10^{15}$ G. It is believed that at center the magnetic field may be higher than that at the surface. However, neutron star can sustain at most the magnetic field $\\sim10^{18}$ G based on dimensional analysis. Within the range of maximum attainable field strength, we study the effect of the magnetic field on the neutron star matter. We model the nuclear matter with relativistic mean field approach considering the possibility of appearance of hyperons at higher density. We find that beyond the magnetic field of the order of $10^{18}$ G, the matter becomes unstable which limits the maximum magnetic field at the center of magnetars. We also find that even at maximum value of magnetic field which is realistic for neutron stars, the effect of magnetic field on highly dense nuclear matter is not so pronounced.
Torsional multipole magnetic response of a heavy spherical nucleus
1995-01-01
The predictions of the distorted Fermi-sphere model for magnetic isoscalar resonances are summarized. In this model a heavy spherical nucleus is thought of as a charged piece of spin and isospin saturated nuclear Fermi-continuum possessing properties of an elastic-like matter. The magnetic resonances are described in fluid-dynamical terms and interpreted as manifestations of elastic torsional vibrations of the nucleus. The process of nuclear magnetization induced by inelastically scattered electrons is described as a transition from a currentless ground state to a magnetized excited one which is characterized by a non-zero magnetic multipole moment. We present calculations of a complete set of integral characteristic parameters of Mlambda, T = 0 resonances such as position of energy peak, excitation probability and magnetic oscillator strength ...
2001-01-01
The system of measurement and stabilization of the magnetic field in the superconducting 7 T wave length shifter (WLS), designed at Budker Institute of Nuclear Physics are described. The measurements are performed by nuclear magnetic resonance (NMR) magnetometer at two points of the WLS magnetic field. Stabilization of the field is provided by the current pumping system. The stabilization system is based on precise NMR measurement of magnetic field as a feedback signal for computer code which control currents inside the superconducting coils. The problem of the magnetic field measurements with NMR method consists in wide spread of field in the measured area (up to 50 Gs/mm), wide temperature range of WLS operating, small space for probe and influence of iron hysteresis. Special solid-state probes were designed to satisfy this requirements. The accuracy of magnetic field ...
2001-03-15
Magnetic properties of the carbon steel tube which is used as the pipe laying of cooling water in nuclear power plant were measured to research the impediment of thickness diminution of carbon steel tube. Magnetic field distribution of carbon steel tube in the applied magnetic field was simulated by computer program. On the basis of the simulation results, Alnico 5DG and Alnico 5 were selected as the permanent magnets applicable to the carbon steel tube. Sm2Co17 magnet was used to compare the performance of permanent magnets. The experimental apparatus similar to the draining environment of cooling water in nuclear power plant was also manufactured in order to research the impediment of thickness diminution of carbon steel carbon tube.
2001-01-01
Magnetic properties of the carbon steel tube which is used as the pipe laying of cooling water in nuclear power plant were measured to research the impediment of thickness diminution of carbon steel tube. Magnetic field distribution of carbon steel tube in the applied magnetic field was simulated by computer program. On the basis of the simulation results, Alnico 5DG and Alnico 5 were selected as the permanent magnets applicable to the carbon steel tube. Sm2Co17 magnet was used to compare the performance of permanent magnets. The experimental apparatus similar to the draining environment of cooling water in nuclear power plant was also manufactured in order to research the impediment of thickness diminution of carbon steel carbon tube
Heat capacity of 3He solid films on graphite in weak magnetic fields
2009-01-01
The heat capacities of the second layer 3He solid films adsorbed on a graphite surface were measured in magnetic fields up to 300 G. The applied magnetic fields are considerably weaker than the exchange interaction between the nuclear spins of 3He. The results reveal unexpected behaviors. In the antiferromagnetic film, the double peak structure of heat capacity is enhanced by the magnetic fields. In the ferromagnetic films, the heat capacity peaks are remarkably reduced. These results might indicate that the ferromagnetic films do not demonstrate simple fully saturated ferromagnetism and that the magnetic fields strongly affect magnetic frustration
Effect of Nuclear Quadrupole Interaction on the Relaxation in Amorphous Solids
2005-02-25
Recently it has been experimentally demonstrated that certain glasses display an unexpected magnetic field dependence of the dielectric constant. In particular, the echo technique experiments have shown that the echo amplitude depends on the magnetic field. The analysis of these experiments results in the conclusion that the effect seems to be related to the nuclear degrees of freedom of tunneling systems. The interactions of a nuclear quadrupole electrical moment with the crystal field and of a nuclear magnetic moment with magnetic field transform the two-level tunneling systems inherent in amorphous dielectrics into many-level tunneling systems. The fact that these features show up at temperatures $T<100mK$, where the properties of amorphous materials are governed by the long-range $R^{-3}$ interaction between tunneling systems, suggests that this interaction is responsible for the magnetic field dependent relaxation. We have developed a theory of many-body relaxation in an ensemble of interacting many-level tunneling systems and show that the relaxation rate is controlled by the magnetic field. The results obtained correlate with the available experimental data. Our approach strongly supports the idea that the nuclear quadrupole interaction is just the key for understanding the unusual behavior of glasses in a magnetic field.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of impaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of impaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Spin microscope based on optically detected magnetic resonance
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Self-shielding superconducting solenoid systems
1988-05-15
Superconducting solenoid systems which produce large magnetic fields can be designed to utilize flux conservation to cancel fluctuations in the ambient magnetic field in which they are located. Such self-shielding solenoids could be very useful for mass spectroscopy of trapped particles, nuclear magnetic resonance experiments, and magnetic resonance imaging.
Precise measurements of magnetic field parameters of the multiples for the SLS storage ring
2000-01-01
The multipoles for SLS Storage Ring having very hard requirements to the manufacture and the alignment of the multipoles relative to the ideal axes were manufactures and magnetic measured by the Budker Institute of Nuclear Physics. The Rotating Coil Systems (RCS) for the precise magnetic measurements are described in the paper. The main RCS parameters are discussed. Such precision magnetic measurement system as RCS permits obtaining the harmonic coefficients, axis position and roll angle with high accuracy
Molecular structure and motion in zero field magnetic resonance
Zero field magnetic resonance is well suited for the determination of molecular structure and the study of motion in disordered materials. Experiments performed in zero applied magnetic field avoid the anisotropic broadening in high field nuclear magnetic resonance (NMR) experiments. As a result, molecular structure and subtle effects of motion are more readily observed.
Molecular structure and motion in zero field magnetic resonance
1989-10-01
Zero field magnetic resonance is well suited for the determination of molecular structure and the study of motion in disordered materials. Experiments performed in zero applied magnetic field avoid the anisotropic broadening in high field nuclear magnetic resonance (NMR) experiments. As a result, molecular structure and subtle effects of motion are more readily observed.
Magnetic diffuse scattering: a theorist`s perspective
1996-11-01
We attempt to show that magnetic diffuse scattering is the natural probe for frustrated antiferromagnetism. Comparison between nuclear and magnetic diffuse scattering compares the range of atomic clustering with the range of the magnetic impurity. At low temperature frustration is expected to lead to large differences which are a natural signature for the relevance of such frustration effects. We provide some elementary examples in first-row transition metals which display fairly dramatic effects. (author) 11 figs., tabs., 8 refs.
Kernel Design of a Flexible Software Framework for Magnetic Measurements at CERN
2009-01-01
The kernel design of the Flexible Framework for Magnetic Measurements (FFMM), under development at the European Organization for Nuclear Research (CERN), is described. The design aims at satisfying the critical scenario of short-term requirement variability for the small batches of magnets after the commissioning for the Large Hadron Collider (LHC). The experimental test results of software flexibility and scalability are illustrated for a case study of superconducting magnets in warm and cold on-field conditions.
Entanglement between states of single quadrupole nuclear spin
2010-05-18
We study entanglement between quantum states of multi level spin system of a single particle considering a nucleus with spin 3/2 in both the internal electric field gradient and the external magnetic field. It was shown that entanglement is achieved by applying a magnetic field to a single particle at low temperature (~ 5 mK). In this temperature range, the numerical calculation revealed the coincidence between magnetization and concurrence. As a result, the magnetization can be used as an entanglement witness for such systems.
Effects of nuclear magnetic resonance on implanted cardiac pacemakers
1983-12-01
The effects of magnetic fields on implanted cardiac pacemakers were studied. Minimum intensity of magnetic field required for changing the movement of pacemakers from demand mode to asynchronous (ASCN) mode was 11 gauss, although it depended on the kinds of apparatus and the direction of magnetic field. The possibility is present that critical arrhythmia might occur when ASCN mode sometimes causes R on T. It is therefore recommended that NMR imaging should be avoided in patients with implanted cardiac pacemakers. (Namekawa, K.).
ELECTRONIC INSTRUMENTATION FOR PROJECT 6.2, OPERATION PLUMBBOB
Magnetic component measurements were made of the near magnetic field associated with a nuclear detonation. The instrumentation design consisted of signal pick-up loops, shielded signal lines, and a self-powered shielded package containing a magnetic tape recorder and associated control circuits. The design and performance of the automatic, multichannel, wide-band magnetic tape recording system are described. (auth)
Charge Fluctuations from the Chiral Magnetic Effect in Nuclear Collisions
2010-09-07
We derive a nonlocal effective Lagrangian for the chiral magnetic effect. An electric field is generated by winding number fluctuations of the nonabelian gauge field in the presence of a strong magnetic field. We estimate the magnitude of charge asymmetry fluctuations with respect to the reaction plane induced by the chiral magnetic effect in relativistic heavy ion collisions. We find that they are below $10^{-4}$, substantially smaller than the signal observed in the STAR experiment.
2000-12-15
The technique of {beta}-NMR/ON and its use for measurement of nuclear magnetic moments is briefly reviewed. Recent magnetic moment measurements are reported on {sup 67}Ni and {sup 67}Cu. The relevance of magnetic moments of single-particle (hole) states for study of effects of configuration mixing and mesonic exchange currents is discussed.
2000-01-01
The technique of beta-NMR/ON and its use for measurement of nuclear magnetic moments is briefly reviewed. Recent magnetic moment measurements are reported on 67Ni and 67Cu. The relevance of magnetic moments of single-particle (hole) states for study of effects of configuration mixing and mesonic exchange currents is discussed
1986-01-01
Solid-state cross-polarization magic angle spinning 31P n.m.r. spectroscopy, single-crystal X-ray structure determination, and i.r. spectroscopy have been used to investigate the properties of the adducts of triphenylphosphine with silver(1) nitrate: Ag( PPh,) NO,, (1); Ag( PPh,),NO,, (2); Ag( PPh,),NO,, (3); and Ag( PPh,),NO,, (4). The value of 'J(Ag-P) decreases with increasing co-ordination number: (1 ), 780; (2), 470; (3), 31 0; and (4), 190 Hz, paralleling solution results. Single-crystal X-ray structure determinations of compounds (2)-(4) have been performed: (2), triclinic, space group P i , a = 11.821 (3), b = 11.990(3), c = 13.660(3) A, u = 102.05(2), p = 11 2.80(2), and y = 105.30(2)", yielding R = 0.036 for 4 090 'observed' reflections; Ag-P 2.443(1) and 2.440(1) A, P-Ag-P 138.21 (5)"; (3), monoclinic, space group P2,/n, a = 18.984(5), b = 13.71 0(3), c = 17.900(4) A, and p = 94.94(2)", yielding R = 0.053 for 5 126 reflections; Ag-P 2.630(2), 2.525(1), and 2.545 2) A, P-Ag-P 11 8.37(5), 11 2.07(4), and 11 6.44(5)"; (4), trigonal, space group R3, a = 19.07(2) A , and u = 43.77(5)", yielding R = 0.060 for 1 903 observed reflections; Ag-P 2.643(3) and 2.671 (4) A, P-Ag-P 109.49(12) and 109.45(10)". Structures (2) and (3) [and (l)] are isomorphous with the analogous triphenylarsine compounds. In all cases the nitrate group is only weakly co-ordinated [and is ionic in (4) 3: Ag-0 2.464(4) and 2.649(4) in (2), 2.684(6) and 2.775(6) A in (3). These weak interactions are reflected in the small splitting observed for the asymmetric N-0 stretching vibrational mode compared to the analogous copper( I) compounds. Publisher: http://dx.doi.org/10.1039/DT9860001965; Royal Society of Chemistry; United Kingdom; http://www.rsc.org/Publishing/Journals/dt/ Relation: Journal of the Chemical Society, Dalton Transactions; 1965; 1970; N; 1986 Format: 816353 bytes; application/pdf Other identifier: 1472-7773 Language: en_AU Rights: Copyright 1986 Royal Society of Chemistry. This is the author-manuscript version of the paper. Reproduced in accordance with the copyright policy of the publisher.; Y
1994-12-31
In this project the structure of soil organic matter was studied with C-13 and N-15 solid state high resolution NMR spectroscopy. In this context composts were produced from several plant species grown on N-15 enriched fertilizers. The composting could until now be studied for a period of 700 days. The characterization of these composts should provide information about nitrogen dynamics in the soil. In addition the composts were used for the optimisation of the NMR parameter of both nuclei mentioned about. The sensitivity of the N-15 nucleus for NMR studies at natural abundance is very low, because of the low natural abundance (0.4%) and the low gyromagnetic ratio. Therefore the compost enriched to 90% N-15 were used for the very spectrometer time consuming optimisation experiments. With the experience gathered during these studies we succeeded in obtaining natural abundance N-15 CPMAS spectra of complete soils and NaOH-extracts. In all N-15 spectra gathered hitherto, more than 90% of the total signal intensity of the nitrogen is present in the form of aminogroups (of the total intensity approx. 70% is found in the amide/peptide range while amino resp. ammoniumgroups contribute approx. 10% each). Heterocyclic aromatic nitrogen cannot be identified. The results have been presented at several international meetings and are compiled in some publications. (orig.) [Deutsch] In diesem Projekt wurde bodenorganische Materie mit Hilfe der C-13 and N-15 Kernresonanzspektroskopie untersucht. Dazu wurden Komposte aus einigen Pflanzen, die aus dem N-15 angereicherten Naehrloesungen gezogen wurden, hergestellt. Die Kompostierung konnte bis jetzt ueber eine Zeitdauer von 700 Tagen verfolgt werden. Mit diesem Kompost sollte einmal die chemische Dynamik des Stickstoffs im Boden charakterisiert werden und es sollte zum anderen versucht werden, die Aufnahmebedingungen fuer die Spektroskopie beider oben angegebenen Kerne zu optimieren. Da wegen der geringen natuerlichen Haeufigkeit (0,4%) und des kleinen gyromagnetischen Faktors die Empfindlichkeit des N-15 Kerns fuer magnetische Resonanzmessungen sehr gering ist, mussten fuer die zeitraubenden Optimierungsversuche die auf 90% N-15 angereicherten Komposte verwendet werden. Nach diesen Vorversuchen gelang es, die N-15 CPMAS Spektren von Gesamtboeden und NaOH-Extrakten mit natuerlicher Stickstoffisotopenzusammensetzung aufzunehmen. Alle N-15 Spektren zeigen, dass mehr als 90% des in dem bodenorganischen Material vorliegenden Stickstoffs als Aminogruppen vorliegen. (Verteilt auf Amid/Peptid etwa 70% und Amino- sowie Ammoniumgruppen je etwa 10%). Heterozyklische aromatische Stickstoffverbindungen koennen nicht nachgewiesen werden. Die Arbeiten wurden und werden auf internationalen Tagungen vorgestellt und sind in einigen Publikationen zusammengefasst. (orig.)
University of Maryland partnership receives $7.9M from NIH for superconducting research ...
2010-08-11
The University of Maryland, in partnership with the University of Maryland, Baltimore and UMBC, has received a $7.9 million federal grant to acquire a superconducting 950 MHz Nuclear Magnetic Resonance magnet that will ...
University of Maryland School of Medicine receives $7.9 million grant for 'super' research ...
2010-08-11
The University of Maryland School of Medicine has received a $7.9 million NIH grant to acquire a superconducting 950 MHz Nuclear Magnetic Resonance magnet that will help researchers unravel the mysteries of molecules ...
The photoelectric effect at the low temperature graphene in the strong magnetic field
2007-07-19
We derive the differential probability of the photoelectric effect realized at the very low temperature graphene in the very strong magnetic field. The relation of this effect to the elementary particle physics, atomic physics and nuclear physics is considered.
Test Proposal for Spherical Shock Waves in Nearly Parallel Magnetic Fields
1956-02-15
A test proposal. Theoretical treatment of energy disruption (fireballs) from a high altitude nuclear detonation due to magnetic field interaction, with a proposal for experimental verification. Nothing of factual nature; only conjecture.
... light curves for the nuclear regions of a sample of 117 nearby galaxies, ... For many targets Doppler imaging, both conventional and magnetic, will be pursued. ..... sustained by the so-called Thermal Relaxation Oscillation (TRO) cycle. ... The formation and evolution of a magnetic dynamo is an integral part of ...
1984-12-11
A hydraulic shock absorber of the dash pot kind for use with electrically conducting liquid such as sodium, has magnet means for electro magnetically braking a stream of liquid discharged from the cylinder. The shock absorber finds use in a liquid metal cooled nuclear reactor for arresting control rods.
Detection at a distance for more sensitive MRI
2004-03-15
Remote-detection nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) depends on physically separating the two basic steps of signal encoding and detection -- normally carried out in the same instrument ...
Biomedical Investigations with Laser-Polarized Noble Gas Magnetic Resonance
We are developing laser-polarized noble gas nuclear magnetic resonance (NMR) as a novel biomedical imaging tool for ground-based and eventually space-based application. This emerging multidisciplinary ...
Biomedical Investigations with Laser-Polarized Noble Gas Magnetic Resonance
We pursued advanced technology development of laser-polarized noble gas nuclear magnetic resonance (NMR) as a novel biomedical imaging tool for ground-based and eventually space-based application. This ...
A new stress test device for cardiac nuclear magnetic resonance studies
1990-01-01
A technique has been developed to exercise human subjects during acquisition of MRI and Magnetic Resonance Spectroscopy data in order to determine the effects of increased cardiac work on myocardial function and metabolism. (author). 6 refs. 2 figs. 1 tab
Quantum chaos and fluctuations in isolated nuclear spin systems
2006-06-25
Using numerical simulations we investigate dynamical quantum chaos in isolated nuclear spin systems. We determine the structure of quantum states, investigate the validity of the Curie law for magnetic susceptibility and find the spectrum of magnetic noise. The spectrum is the same for positive and negative temperatures. The study is motivated by recent interest in condensed-matter experiments for searches of fundamental parity- and time-reversal-invariance violations. In these experiments nuclear spins are cooled down to microkelvin temperatures and are completely decoupled from their surroundings. A limitation on statistical sensitivity of the experiments arises from the magnetic noise.
Magnetic dipole moment of the doubly closed-shell plus one proton nucleus $^{49}$Sc
2010-03-03
It is proposed to measure the magnetic moment of $^{49}$Sc by the Nuclear Magnetic Resonance on Oriented Nuclei (NMR-ON) method using the NICOLE on-line nuclear orientation facility. $^{49}$Sc is the neutron rich, doubly closed-shell, nucleus $^{48}$Ca plus one proton. Results will be used to deduce the effective g-factors in the $^{48}$Ca region with reference to nuclear structure and meson exchange current effects.
Magnetic analyzer for charged-particles from nuclear reactions
1950-10-01
A double focusing magnetic spectrometer for detecting and analyzing charged particles from nuclear reactions is described. The magnetic field, varying as 1/(sq.rt. r) near an average radius of 10.5 in., extends over a semicircle yielding object and anastigmatic image positions some distance outside of the region of strong field. The acceptance solid angle is Omega = 0.0061 sterad, and the momentum resolution with an 8-mm slit at the detector is R = 128. The ultimate resolution determined by spherical aberration and some residual astigmatism is about 1000. Applications to the study of the energy and yield of nuclear reaction products are discussed.
1983-12-01
Equipments with a cathode-ray tube, such as a heart rate monitoring device and an ultrasound monitoring device, were greatly influenced by nuclear magnetic resonance computed tomography. The murmur was detected on waves of ECG at the time of a switchover of inclined magnetic field. Various kinds of ferromagnetic surgical clips and patients' belongings, which were enclosed in a phantom, exercised a great influence on the magnetic field, resulting in the occurrence of artifacts. (Namekawa, K.).
Refrigeration system of a large superconducting spectrometer magnet
1990-09-01
A sector type superconducting spectrometer magnet, SKS, for nuclear physics experiments is under construction by the Institute for Nuclear Study, University of Tokyo with collaboration from KEK. The central magnetic field is 3 tesla with a magnet gap of 50 cm. The stored energy is 11.2 MJ at the maximum operation current of 500 A. Easy operation and maintenance have been taken into consideration. It is intended to make the heat leak as small as 3 W at 4 K. A small refrigerator is to be used for thermal insulation at 80 and 20 K in combination with a medium size refrigerator at 4 K. (author).
2010-01-01
Although nuclear magnetic resonance in low fields around or below the Earth's magnetic field is almost as old as nuclear magnetic resonance itself, the recent years have experienced a revival of this technique that is opposed to the common trend towards higher and higher fields. The background of this development is the expectation that the low-field domain may open a new window for the study of molecular structure and dynamics. Here, we will give an overview on the specific features in the low-field domain, both from the technical and from the physical point of view. In addition, we present a short passage on the option of magnetic resonance imaging in fields of the micro-Tesla range.
Measurement of the magnetic moment of the one-neutron halo nucleus $^{11}Be$
The magnetic moment of $^{11}$Be was measured by detecting nuclear magnetic resonance signals in a beryllium crystal lattice. The experimental technique applied to a $^{11}$Be$^+$ ion beam from a laser ion source includes in-beam optical polarization, implantation into a metallic single crystal and observation of rf resonances in the asymmetric angular distribution of the $\\beta$-decay ($\\beta$-NMR). The nuclear magnetic moment $\\mu(^{11}{\\rm Be}) = -1.6816(8)\\,\\mu_N$ provides a stringent test for theoretical models describing the structure of the 1/2$^+$ neutron halo state.
2001-01-01
The structure, magnetic properties and nuclear gamma-resonance on the 57Fe nuclei in the Fe/Ta superlattices are studied and functions of the superfine fields distribution probability on these nuclei are reestablished. The oscillating dependence of spontaneous magnetization on the Ta layers thickness in identified and parameters of the bilinear indirect exchange interaction between the Fe-layers are determined. It is shown that the spontaneous magnetization for certain superlattices significantly exceeds its value for pure Fe
Fuels characterization studies
Current analytical techniques used in the characterization of broadened properties fuels are briefly described. Included are liquid chromatography, gas chromatography, and nuclear magnetic resonance spectroscopy. High ...
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