Science.gov (United States)

... charge carriers in strained p-Ge in crossed electric and magnetic fields was studied by means of measurements of spontaneous radiation intensity. ...

International Nuclear Information System (INIS)

The author briefly discusses definition of terms, gives an introduction to measurement techniques and describes the characteristics of various low-frequency fields and their causes using typical examples: natural electric fields (thunderstroms), natural magnetic fields, technical electric constant fields (urban transportation, households), static magnetic fields (urban transportation, nuclear magnetic resonance imaging), technical electric alternating fields (high-voltage transmission lines, households), and magnetic alternating fields (high-voltage transmission lines). The author discusses both occupational exposure and that of the general public while underpinning his statements by numerous tables, measurement diagrams and charts. (Uhe).

KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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KoreaScience (Korea)

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International Nuclear Information System (INIS)

This introductory paper surveys potential sources of electric magnetic, and electro-magnetic fields. Various cases are discussed to exemplify the total frequency range: nuclear magnetic resonance tomography, high-voltage transmission lines, transformer stations, effect lighting balls, military transmitters, transmitter towers of the Postal Services and other operators, mobile radiotelephone equipment, large broadcasting transmitters, radar radiation, high-frequency heat therapy. There is evidence suggesting that electric, magnetic and electro-magnetic fields may possibly represent a certain nuisance or health hazard even at field strength occuring in equipment used for every-day-life purposes, with an emphasis on their possible actions and effects in children and adolescents. The author discusses, in conclusion, the ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

KoreaScience (Korea)

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J-STORE (Japan)

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KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

Discussion of an electrohydraulic and magnetic forming process

Energy Technology Data Exchange (ETDEWEB)

The author briefly discusses definition of terms, gives an introduction to measurement techniques and describes the characteristics of various low-frequency fields and their causes using typical examples: natural electric fields (thunderstroms), natural magnetic fields, technical electric constant fields (urban transportation, households), static magnetic fields (urban transportation, nuclear magnetic resonance imaging), technical electric alternating fields (high-voltage transmission lines, households), and magnetic alternating fields (high-voltage transmission lines). The author discusses both occupational exposure and that of the general public while underpinning his statements by numerous tables, measurement diagrams and charts. (Uhe) [Deutsch] Nach einer kurzen Diskussion der Begriffsdefinitionen und einer ...

Energy Technology Data Exchange (ETDEWEB)

It is shown that pure NQR can be utilized as a platform for quantum computing without applying a high external magnetic field. By exciting each resonance transition between quadrupole energy levels with two radio-frequency fields differing in phase and direction, the double degeneracy of the spin energy spectrum in an electric field gradient is removed. As an example, in the case of I=7/2 (nuclei {sup 133}Cs or {sup 123}Sb) the energy spectrum has eight levels which can be used as three qubits. (orig.)

UK PubMed Central (United Kingdom)

OBJECTIVES: To define a method for measurement of the cross sectional area and volume of the quadriceps femoris muscle using magnetic resonance imaging (MRI) in conjunction with stereology, and to compare...Full Text Available

UK PubMed Central (United Kingdom)

Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative...Full Text Available

UK PubMed Central (United Kingdom)

A technique of low-field pulsed proton nuclear magnetic resonance (NMR) spin relaxation is described for assessment of age-related structural changes (dentin and pulp) of human teeth in...Full Text Available

KoreaScience (Korea)

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Science.gov (United States)

PMID:9226309

International Nuclear Information System (INIS)

2010 [1 p.] Germany Repp, Felix El-Miladi, Nouri Hoehl, Christian Jahanbakhsh,

KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Superconducting rf cavities are increasingly used in accelerators. Gradient is a parameter of particular importance for the ILC. Much progress in gradient has been made over the past decade, overcoming problems of multipacting, field emission, and breakdown triggered by surface impurities. However, the quenching limit of the surface magnetic field for niobium remains a hard limitation on cavity fields sustainable with this technology. Further exploration of materials and preparation may offer a path to surpassing the current limit. For this purpose, we have designed a resonant test cavity. One wall of the cavity is formed by a flat sample of superconducting material; the rest of the cavity is copper or niobium. The H field on the sample wall is 75% higher than on any other surface. Multipacting is avoided by use of a mode with no surface electric field. The cavity will be resonated through a coupling ...

Energy Technology Data Exchange (ETDEWEB)

Electron paramagnetic resonance was used to investigate surface-coated magnetite-based magnetic fluids doped with TEMPOL. Two magnetic fluid samples, having magnetite nanoparticles with average diameter of 94 A and coated with different coating layers (lauric acid plus ethoxylated polyalcohol in one case and oleoylsarcosine in the other case), were doped with TEMPOL (6 mM and pH 7.4) and investigated as a function of the nanoparticle concentration. The resonance field and the resonance linewidth both scale linearly with the nanoparticle concentration.

Energy Technology Data Exchange (ETDEWEB)

Recent developments in solid-state radio frequency (RF) power technologies allow for the practical consideration of RF heated plasmas for space propulsion. These technologies permit the use of any electrical power source, de-couple the power and propellant sources, and allow for the effcient use of both the propellant mass and power. Effcient use of the propellant is obtained by expelling the rocket exhaust at the highest possible velocity, which can be orders of magnitude higher than those achieved in chemical rockets. Handling the hot plasma exhaust requires the use of magnetic nozzles, and the basic physics of ion detachment from the magnetic eld is discussed. The plasma can be generated by RF using helicon waves to heat electrons. Further direct heating of the ions helps to reduce the line radiation losses, and the magnetic geometry is tailored to allow ion cyclotron resonance ...

International Nuclear Information System (INIS)

Several refrigerators for liquid helium and liquid nitrogen systems have been integrated successfully into IGC manufactured whole body Magnetic Resonance Imaging (MRI) magnet systems. The refrigerators have been tested in systems with magnetic fields of 0.6T to 1.5T. Tests were performed to study the effectiveness of the refrigerators, the magnetic field effects on the refrigerators, the effect of the refrigerators on the field uniformity and magnetic resonance image quality. The interface between the refrigerator and the whole body MRI magnet system cryostat was specifically designed to allow retrofit to the existing IGC magnet systems, while ensuring good heat transfer characteristics and good vibration isolation from the cryostat. The interface between the refrigerator and the cryostat and the ...

International Nuclear Information System (INIS)

The MRI's of 16 patients with either primary or secondary lymphatic disorders are evluated and the findings are compared to those from lymphangioscintigraphy or surgery. (author).

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Many nondestructive beam position monitors are known. However, these devices can not be used for DC particle beam diagnostics. We investigated a method of beam diagnostics applicable for the operative control of DC high power e-beam inside closed waveguide. A design of the detector for determination of{open_quote} center of mass {close_quote} position of DC particle beam was developed. It was shown that the monitor can be used as a nondestructive method for the beam position control in resonators. Magnetic field of the particle beam outside a resonator is used. The detector consists of the steel yokes and magnetic field sensors. The sensors measure magnetic fluxes in the steel yokes fixed outside the resonator. When the particle beam changes its position, these magnetic fluxes also change. Beam displacement sensitivity of the monitor depends ...

UK PubMed Central (United Kingdom)

SOME SCIENTISTS ALLEGE that exposure to electric and magnetic fields generated by electric power delivery systems is responsible for certain cancers (particularly among children), reproductive dysfunction,...Full Text Available

International Nuclear Information System (INIS)

This book is an anatomical reference for cranial magnetic resonance imaging (MRI) studies in neonates and infants. It contains 122 clear, sharp MRI scans and drawings showing changes in the normal appearance of the brain and skull during development. Sections of the atlas depict the major processes of maturation: brain myelination, development of the corpus callosum, development of the cranial bone marrow, and iron deposition in the brain. High-quality scans illustrate how these changes appear on magnetic resonance images during various stages of development.

Science.gov (United States)

Nuclear magnetic resonance results are presented for a number of NaCl-type compounds and cubic Laves-phase type compounds of uranium, neptunium, and plutonium. Special emphasis is placed on the Knight shift and spin-lattice relaxation time measurements and their interpretation in terms of localized or itinerant pictures of the 5Line integral electrons.

International Nuclear Information System (INIS)

We reviewed retrospectively the magnetic resonance (MR) images of 14 soft-tissue lesions of fibromatosis (desmoid tumors) encountered in 11 patients. The lesions were typically inhomogeneous in texture and round to oval in configuration. Margins were well-defined in 78% of the lesions at presentation and were infiltrating in all recurrences. (orig./DG).

UK PubMed Central (United Kingdom)

A nonperturbing 13C nuclear magnetic resonance (NMR) method was used to monitor the equilibrium distribution of carboxyl 13C-enriched fatty acids (FA) between distinct binding sites on human serum albumin,...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundCardiovascular magnetic resonance (CMR) allows volumetric carotid plaque measurement that has advantage over 2-dimensional ultrasound (US) intima-media thickness (IMT)...Full Text Available

UK PubMed Central (United Kingdom)

The purpose of this study was to assess the effect of a 735-kV transmission line on the electric and magnetic field exposures of people living at the edge of the line's right of way. Exposure of 18...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The Advanced Photon Source injector synchrotron is a 7-GeV positron machine with a standard alternating gradient lattice. The calculated effect of dipole magnet strength errors on the orbit distortion, simulated by Monte Carlo, was reduced by sorting pairs of magnets having the closest simulated measured strengths to reduce the driving the term of the integer resonance nearest the operating point. This method resulted in a factor of four average reduction in the rms orbit distortion when all 68 magnets were sorted at once. The simulated effect of magnet measurement experimental resolution was found to limit the actual improvement. The {Beta}-beat factors were similarly reduced by sorting the quadrupole magnets according to their gradients.

International Nuclear Information System (INIS)

... nuclear electric moments nuclear magnetic moments nuclear radii quadrupole

Science.gov (United States)

The purpose of this study was to develop a simple motion measurement system with magnetic resonance (MR) compatibility and safety. The motion measurement system proposed here can measure 5-DoF motion signals without deteriorating the MR images, and it has no effect on the intense and homogeneous main magnetic field, the temporal-gradient magnetic field (which varies rapidly with time), the transceiver radio frequency (RF) coil, and the RF pulse during MR data acquisition. A three-axis accelerometer and a two-axis gyroscope were used to measure 5-DoF motion signals, and Velcro was used to attach a sensor module to a finger or wrist. To minimize the interference between the MR imaging system and the motion measurement system, nonmagnetic materials were used for all electric circuit components in an MR shield room. To remove the effect of RF pulse, an amplifier, modulation circuit, and ...

International Nuclear Information System (INIS)

Excitation of the HF electric field in the local plasma resonance region (LPRR) of inhomogeneous plasma by pumping electric field or modulated electron beam results to appearance of the ponderomotive force that presses plasma out of this region. Density cavity is formed in the LPRR due to this field. Further dynamics in this region depends on the plasma properties. For plasma with hot electrons ion-acoustic pulses run away from the cavity. at the local density maximum the new peak of electric field is excited. It results to the formation of new density cavity, etc. For isothermal plasma the density jump is formed.

International Nuclear Information System (INIS)

It is shown that recuperator in which the thermal energy of particles is transformed into electric oue under drift in crossed fields is naturally coupled with dragontype magnetic confinement system, so the recuperation process can be initiated in the dragon magnetic field. A number of questions occuring under analysis of recuperator-dragon system is considered, including the dynamics of particle transfer to the recuperator, the share of particles entering the recuperator, the effect of rotational transform and the recuperation efficiency.

UK PubMed Central (United Kingdom)

Hypercapnia is often used as vasodilatory challenge in clinical applications and basic research. In functional magnetic resonance imaging (fMRI), elevated CO₂ is applied to derive stimulus-induced...Full Text Available

UK PubMed Central (United Kingdom)

The purpose of this study was to synthesize biocompatible polyvinylpyrrolidone (PVP)-coated iron oxide (PVP-IO) nanoparticles and to evaluate their efficacy as a magnetic resonance imaging (MRI)...Full Text Available

UK PubMed Central (United Kingdom)

High resolution structural elucidation of macromolecular structure by solid-state nuclear magnetic resonance requires the preparation of uniformly aligned samples that are isotopically labeled. In...Full Text Available

UK PubMed Central (United Kingdom)

Currently several groups are actively researching the integration of a megavoltage teletherapy unit with magnetic resonance (MR) imaging for real-time image-guided radiotherapy. The use of a...Full Text Available

International Nuclear Information System (INIS)

French English ... Orig. Title Imagerie IRM des lesions focales hepatiques avec les antennes de surface en reseau phase (phased array): apnee ou imagerie haute resolution?.

UK PubMed Central (United Kingdom)

Arriving at a firm diagnosis of neurosarcoidosis continues to pose serious problems, particularly when evidence of granulomatous disease outside the nervous system is lacking. The commonest mode of...Full Text Available

UK PubMed Central (United Kingdom)

Accurate and automated methods for measuring the thickness of human cerebral cortex could provide powerful tools for diagnosing and studying a variety of neurodegenerative and psychiatric disorders....Full Text Available

UK PubMed Central (United Kingdom)

The percentages of total airflows over the nasal respiratory and olfactory epithelium of female rabbits were calculated from computational fluid dynamics (CFD) simulations of steady-state inhalation....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Short communication

UK PubMed Central (United Kingdom)

In this study, we aimed to demonstrate whether spontaneous fluctuations in the blood oxygen level dependent (BOLD) signal derived from resting state functional magnetic resonance imaging (fMRI) reflect...Full Text Available

UK PubMed Central (United Kingdom)

The purpose of this study was to investigate whether genetically determined properties of muscle metabolism contribute to the exceptional physical endurance of world-class distance runners. ATP, phosphocreatine,...Full Text Available

UK PubMed Central (United Kingdom)

In Diffusion Tensor Magnetic Resonance Image (DT-MRI) processing a 2^nd order tensor has been commonly used to approximate the diffusivity function at each lattice...Full Text Available

UK PubMed Central (United Kingdom)

Due to the widespread clinical use of imaging modalities such as ultrasonography, computed tomography and magnetic resonance imaging (MRI), previously unsuspected liver masses are increasingly being...Full Text Available

UK PubMed Central (United Kingdom)

The polymorphic phase behavior of a homologous series of n-saturated 1,2-diacyl phosphatidylethanolamines was investigated by differential scanning calorimetry, 31P-nuclear magnetic resonance, and Fourier...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

At the conclusion of polarized proton commissioning in February 1986, protons with an average polarization of 45%, momentum of 21.7 GeV/c, and intensity of 2 x 10/sup 10/ protons per pulse, were extracted to an external polarimeter at the Brookhaven AGS. In order to maintain this polarization, five intrinsic and nearly forty imperfection depolarizing resonances had to be corrected. An apparent interaction between imperfection and intrinsic resonances occurring at very nearly the same energy was observed and the correction of imperfection resonances using ''beat'' magnetic harmonics discovered in the previous AGS commissioning run was further confirmed.

British Library Electronic Table of Contents (United Kingdom)

Abstract Neurodegenerative and neurometabolic disorders may cause significant morbidity and mortality in children. Imaging is important in early diagnosis of metabolic disorders and in determining the extent of brain injury. Especially after the development of new techniques such as diffusion-weighted magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS), neuroimaging plays more important role in the diagnosis and management of these disorders. In these disorders, usually a mutation causes a clinically significant block in one or more metabolic pathways. This blockage usually results in either a deficiency of the product or in an accumulation of substrate with damage induced by either storage or toxicity. The presenting symptoms are usually nonspecific. In some of the ...

International Nuclear Information System (INIS)

In Nuclear Magnetic Resonance (NMR) imaging, contrast is dependent on the emission of radiofrequency waves by atomic nuclei, balanced by several parameters. The high information content of NMR images is due to the multiplicity of its parameters. However, this advantage introduces a difficulty in the interpretation of the contrast. There are three contrast parameters for each tissue: hydrogen nuclei density; relaxation time T1; relaxation time T2. Contrast may be enhanced towards any of these parameters by increasing the emission of radiowaves by atomic nuclei using particular pulse sequences.

Energy Technology Data Exchange (ETDEWEB)

The authors report the findings of Aicardi syndrome, a disease of unknown etiology composed of multiple spasms, chorioretinal lacunae and agenesis of the corpus callosum. They present a case of Aicardi syndrome with characteristic clinical presentation and magnetic resonance imaging findings. The disease, despite being considered rare, has characteristic imaging findings. Over the past years magnetic resonance imaging has improved its ability in demonstrating other findings besides agenesis of the corpus callosum, making the radiologist's role very important in the diagnostic suspicion of this disease. (author)

International Nuclear Information System (INIS)

In the present paper the progress of optimization of soft magnetic properties have been studied by applying different experimental techniques (magnetic measurements, electric measurements, X-ray analysis, and high-resolution electron microscopy observation). It has been shown that an increase in magnetic permeability after optimization annealing can be mainly attributed to annealing out of microvoids. (author)

International Nuclear Information System (INIS)

The results obtained from the magnetization, specific heat and electrical resistivity measurements on a polycrystalline sample of Pr_2Pd_3Si_5 are reported. The temperature dependence of magnetic susceptibility at low field (0.01 T) exhibits pronounced anomaly below 7 K due to antiferromagnetic ordering. The electrical resistivity and specific heat data also exhibit sharp transition at 6.6 K evidencing the onset of antiferromagnetic order. A fit to the electrical resistivity data below 6 K suggests the presence of an energy gap in magnon spectrum in the ordered state. (author)

Science.gov (United States)

Magnetic Forming (10). - Forming of metals (the metal needs only to be an electrical conductor) is achieved without physical contact ...

International Nuclear Information System (INIS)

... gamma cascades kev range 10-100 lifetime lutetium 171 lutetium 173 lutetium

Science.gov (United States)

We proposed and numerically investigated the influence of spatial symmetry on the terahertz frequency region response of composite planar metamaterials based on deformed split ring resonators. Compared with the original simple structures, the composite metamaterials with different spatial symmetries exhibited exotic electromagnetic properties. The electromagnetic response of a specific configuration with C4 symmetry was identical to the structure with simple lattice. Especially, for configurations with broken symmetry, very sharp Drude-like resonances with high quality factor were observed. The electric field and current distribution associated the resonances were analyzed for deep understanding of the underlying physical properties.

CERN Document Server

We calculate the quarkonium dissociation rate in the P and CP-odd domains (bubbles) that were possibly created in heavy-ion collisions. In the presence of the magnetic field produced by the valence quarks of colliding ions, parity-odd domains generate electric field. Quarkonium dissociation is the result of quantum tunneling of quark or antiquark through the potential barrier in this electric field. The strength of the electric field in the quarkonium comoving frame depends on the quarkonium velocity with respect to the background magnetic field. We investigate momentum, electric field strength and azimuthal dependence of the dissociation rate. Azimuthal distribution of quarkonia surviving in the electromagnetic field is strongly anisotropic; the form of anisotropy depends on the relation between the electric and ...

International Nuclear Information System (INIS)

Normal state nuclear magnetic resonance studies of the La_3In, La_3Tl compounds have been made in order to investigate the origin of the large temperature-dependent magnetic susceptibility. It is possible to analyse the different contributions to the susceptibility using Knight-shift and relaxation time T_1 measurements of In"1"1"5 and Tl"2"0"5 nuclei. The exchange enhancement of the spin-susceptibility chisub(pd) is of the same order as that found in A-15 compounds and the strong temperature-dependence of chi(T) is attributed to the presence of a peak in the electronic density of states near the Fermi level. The variation of the Knight-shift in the ternary alloys La_3Xsub(1-y)Xsub(y)sup(') is analogous to that observed in the corresponding La_3X phases, on the other hand the Knight-shift in the carbides La_3XC is temperature independent. (author).

CERN Document Server

The homogeneity of the magnetic field in the LHC dipoles strongly depends on the correct position of the superconducting cables: this is related to the quality of the dipole components, such as the dimension of the coil spacers (copper wedges), of the cable and of the collars. The performance in operational conditions is also affected by the magnetization of the cables. In this work, we analyse the measurements of these quantities during the production of the 1276 LHC dipoles, their trends, and the relation to the measured magnetic field. A novel mtehod to locate electrical shorts based on the analysis of magnetic measurements is also presented, and applications to 15 dipoles reascued during the production is given.

British Library Electronic Table of Contents (United Kingdom)

The magnetic three spin-1/2 model for nanometer-scale molecular cluster V15 is analyzed with the emphasis on the origin of the mixing of different spin levels in the resonance fields that is generally important for the problem of single molecular magnets. The zero-field splitting in the ground quadruplet (two Formula Not Shown levels) is shown to depend mainly on the normal component of AS exchange meanwhile the zero-field splitting in the excited Formula Not Shown multiplet is a second order effect with respect to in-plane components of AS exchange. The normal component of the AS exchange is shown to lead to the exact crossing of the magnetic sublevels at the arbitrary direction of the field. The positions of two crossing/anticrossing points in the ground manifold depend mainly on the iso...

International Nuclear Information System (INIS)

The compound GdPd_2Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The ...

International Nuclear Information System (INIS)

We examine the electric and magnetic strange form factors of the nucleon in the pseudoscalar-vector SU(3) Skyrme model, with special emphasis on the effects of isospin symmetry breaking (ISB). It is found that ISB has a nontrivial effect on the strange vector form factors of the nucleon and its contribution to the nucleon strangeness is significantly larger than one might naively expect. Our calculations and discussions may be of some significance for the experimental extraction of the authentic strangeness.

Energy Technology Data Exchange (ETDEWEB)

The conductance in ferromagnetic Ni nano-wire is quantized in units of 2e{sup 2}/h in the absence of magnetic field, while the units switch to e{sup 2}/h in the magnetic field. The fractional units of 0.7e{sup 2}/h and 1.4e{sup 2}/h with and without magnetic field appear under the application of high bias-voltage. The spin polarization and bias-voltage play an important role in the electric conduction.

International Nuclear Information System (INIS)

The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.

International Nuclear Information System (INIS)

The paper outlines the underlying physical mechanisms by which electric and magnetic fields exist, with particular reference to high voltage transmission lines. Epidemiological and laboratory studies are the two approaches used in research into the subject and the shortcomings and inconstancies in the results are mentioned. Recent epidemiological results are presented together with possible mechanisms between fields and the human body. Attention is drawn to the work of certain international and national bodies concerning the alleged association between electromagnetic fields and ill-health, and their conclusions are reported. Finally, the policy of the Electricity Supply Board in Ireland is outlined. 2 figs.

Energy Technology Data Exchange (ETDEWEB)

We duscuss a resonant microwave trap for neutral atoms. Because of the long spontaneous radiation time this trap is remarkably different from the optical trap. It also has advantages over static magnetic traps that trap the excited spin state of the lowest electronic level, in that atoms predominantly in the spin ground state can be trapped. We analyze the relaxation-ejection lifetime of atoms in such a trap using the formalism of dressed atomic states. Results are appliedi to atomic hydrogen and the possibility of Bose-Einstein condensation is considered.

Energy Technology Data Exchange (ETDEWEB)

This review of methods and designs of transducers for nondestructive determination of the magnitude and nature of the anisotropy of magnetic properties (permeability, induction, coercive force, energy loss due to magnetization reversal) in local portions of ferromagnetic sheet and, in some cases, in individual parts of products. The need to measure the anisotropy is considered for two angles: for the case when the anisotropy is due to the crystallographic texture and determines the main operating characteristics of widely used sheet such as electrical steel and automobile body sheet, and for crystallographically isotropic materials, in which the anisotropy of magnetic properties as a result of mechanical stresses is a measure for determining the internal stresses.

International Nuclear Information System (INIS)

The electrical resistivity, Hall effect, and magnetic susceptibility of single-crystal UPd_2Si_2 have been studied between 4.2 and 300 K. A large anisotropy was observed in both the magnetic and transport properties. There is a quadratic temperature dependence of the resistivity for a range of temperatures between 4.2 and 80 K. At higher temperatures, the resistivity indicates a Kondo-type behavior. The behavior of these quantities is accounted for by the magnetic phase transitions at 108 and 136 K reported from neutron-scattering studies. At high temperatures, the magnetic susceptibility of UPd_2Si_2 is Curie-Wiess-like along the c axis. The temperature dependence of the Hall coefficient above 108 K is accounted for by a theoretical model invoking skew scattering of conduction electrons by localized magnetic moments.

Energy Technology Data Exchange (ETDEWEB)

A broad-based, multidisciplinary research program is being conducted to study biological effects of electric and magnetic fields from high-voltage transmission lines. Assistance and technical support for this program are reported. (DLC)

British Library Electronic Table of Contents (United Kingdom)

Inspired by the recent realizations of quantum dot (QD)-DNA conjugation, we study the spectral density of a magnetic impurity coupled to a mesoscopic semiconducting host. Using a combination of exact diagonalization technique and an analytic approach, we demonstrate that various types of resonances occur according to the relative position of impurity levels (IL) with respect to the host levels (HL). While the usual Coulomb peaks appear when the IL lie inside a band gap, with IL approaching HL and hybridization activated, they shift nonlinearly with the repulsion strength and even undergo splitting for a strong hybridization. When IL merge into HL, multiple resonances of a comblike structure are found along with a parity effect.

International Nuclear Information System (INIS)

Extraskeletal Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET) are widely regarded as clinically and histologically identical tumors which consist of small blue round cells. Extraskeletal ESs/PNETs usually occur in the deep soft tissues of the paraspinal region, chest wall, or lower extremities. However, superficially located cases, so-called cutaneous ESs/PNETs, are exceedingly rare, and the vast majority of the reported cases present as a single small mass. We present magnetic resonance imaging (MRI) findings and clinical course of a unique case of primary cutaneous ES/PNET presenting as numerous huge masses with severe ulceration on them. (orig.)

International Nuclear Information System (INIS)

Magnetic resonance imaging has proven an invaluable method in the diagnosis of joint diseases associated with osteonecrotic, inflammatory, traumatic and degenerative processes. At the clinical level, it has an important role in decisions about the method of treatment and evaluations of the therapeutic success. When the merits of MRT are balanced against those of conventional radiography including tomography and CT, which both ensure better spatial resolution in the visualisation of cortical and spongy bone structures, it becomes quite evident that MRT must not be regarded as an alternative method of imaging but as one that can be used additionally to obtain the most information for the diagnosis of arthropathy. The question as to whether new pulse sequences (snap shots) or invasive techniques like intra-articular injection of paramagnetic substances (MR arthrography) are likely to become routine procedures in the detection of joint diseases ...

International Nuclear Information System (INIS)

Fetal MRI examines non-invasively the unborn fetus. Ultrafast MRI sequences effectively suppress fetal motion. Multiple case reports and studies have shown that fetal MRI is particularly helpful in the evaluation of the central nervous system. The high contrast-to-noise ratio, the high spatial resolution, the multiplanar capabilities, the large field of view and the simultaneous visualisation of fetal and maternal structures have proven to be advantageous. Fetal MRI is particularly helpful in the evaluation of the normal and pathological development of the brain. Despite the fact that no side effects have been reported or are to be expected, the use of MRI during pregnancy is still limited to the second and third trimester of pregnancy. Magnetic resonance imaging contrast media are not to be used as it passes the placenta. Ultrasound remains the primary screening modality for fetal pathology; fetal MRI can serve as an adjunct or second-line ...

International Nuclear Information System (INIS)

Twenty-three patients with intracranial meningiomas were examined by means of magnetic resonance tomography (MRT). In 13 patients the paramagnetic contrast medium gadolinium DTPA was used. Meningiomas show only slight changes in signal intensity compared with brain in the spin-echo mode, the greatest contrast being found on photon density images (TR 1600 ms, TE 35 ms). In T1 images more than 50% of the patients showed a low signal margin between tumour and brain. Hyperostosis of the calvarium is easily recognised, but MRT is unreliable for showing tumour calcification. After intravenous injection of gadolinium DTPA, there was marked homogeneous uptake in the meningiomas. These signs are useful for the diagnosis of a meningioma by MRT. (orig.).

International Nuclear Information System (INIS)

We studied the niobium re-entrant cavity utilized by the Australian group in the Niobe gravitational wave detector. Instead of using their non-contact re-entrant cavity, we plan to change it to a closed one to be used in the parametric transducers of the Brazilian Mario Schenberg detector. The performance of the transducer depends on some cavity parameters such as the electrical Q and the electrical coupling. We measured the resonant frequency and the loaded electrical Q as a function of the probe position in a closed niobium #approx#15 GHz cavity operating at 4.2 K.

International Nuclear Information System (INIS)

The combination of functional and morphological imaging technologies such as positron emission tomography (PET) and X-ray computed tomography (CT) has shown its value in the clinical and preclinical field. However, CT provides only very limited soft-tissue contrast and exposes the examined patient or laboratory animal to a high X-ray radiation dose. In comparison to CT, magnetic resonance tomography (MRI) provides excellent soft-tissue contrast and allows for nuclear magnetic resonance spectroscopy (NMRS) or functional MRI (fMRI). Thus, the combination of PET and MRI has been pursued for several years. First approaches have succeeded using conventional photo multiplier tube (PMT) technology together with light fibers to transfer scintillation light away from the high magnetic field. Latest PET/MRI developments use solid-state light detectors that can be operated even at high ...

International Nuclear Information System (INIS)

Stimulated bremsstrahlung in an undulating electric field in the lasing beam direction (electric wiggler) was shown to be possible from the quantum- mechanical viewpoint. Herein, this possibility is scrutinized from the viewpoint of classical electrodynamics. It is found that if stimulated bremsstrahlung in a transverse undulating magnetic field (magnetic wiggler) occurs, stimulated bremsstrahlung in the electric wiggler must also occur. We further show that a free electron laser (FEL) using a magnetic wiggler to provide a catalyzer field for stimulated bremsstrahlung cannot serve as a practical FEL operating in the soft x-ray region from both theoretical and experimental viewpoints. On the other hand, the authors demonstrate that the FEL using a traveling wake field in a two-beam elliptical pill-box cavity is well suited as a source of coherent radiation in the ...

Energy Technology Data Exchange (ETDEWEB)

A non-invasive, wide-band electromagnetic (EM) impedance difference system for shallow subsurface electrical structure characterization in environmental and engineering problems has been developed at the Lawrence Berkeley National Laboratory (LBNL). Electrical parameters of interest are electrical conductivity and dielectric permittivity that are deduced from the impedance difference data. The prototype system includes a magnetic loop transmitter, which operates between 0.1 MHz and 100 MHz, an electrical dipole antenna for observing the electric field, and a loop antenna for measuring the magnetic field.All antennas are mounted on a cart made of non-metallic material for easy movement of the whole array for profiling. Surface EM impedance difference is obtained by taking the difference of the ratios of the electric ...

Energy Technology Data Exchange (ETDEWEB)

Recently it was demonstrated that long-lived quantum coherence exists during excitation energy transport in photosynthesis. It is a valid question up to which length, time and mass scales quantum coherence may extend, how one may detect this coherence and what, if any, role it plays in the dynamics of the system. Here we suggest that the selectivity filter of ion channels may exhibit quantum coherence, which might be relevant for the process of ion selectivity and conduction. We show that quantum resonances could provide an alternative approach to ultrafast two-dimensional (2D) spectroscopy to probe these quantum coherences. We demonstrate that the emergence of resonances in the conduction of ion channels that are modulated periodically by time-dependent external electric fields can serve as signatures of quantum coherence in such a system. Assessments of experimental feasibility and specific paths towards the experimental ...

UK PubMed Central (United Kingdom)

Multiple memory systems are involved in parallel processing of spatial information during navigation. A series of studies have distinguished between hippocampus-dependent ‘spatial’ navigation,...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Cardiac tumours may display diverse symptoms through potential involvement of any structure of the heart. We describe a case of a highly malignant thymoma with involvement of different cardiac structures with important haemodynamic compromise. With the high sensitivity of transthoracic echocardiography for detection of intracardiac masses, computed tomography and magnetic resonance add essential structural preoperative information on the tumour and surrounding tissue as vessels, pleura, lung and mediastinum.

Energy Technology Data Exchange (ETDEWEB)

Positron emission tomography (PET) and magnetic resonance imaging (MRI) studies were performed on a case of neuro-Behcet's syndrome. In accordance with the clinical signs, FDG PET (using /sup 18/F-labeled 2-F-2'-desoxyglucose) revealed disseminated storage defects in the cerebrum and cerebellum. Focal regions of enhanced signal intensity were demonstrated in the parietal white matter of the cerebrum in T2-weighted images and in the brain stem by MRI. (orig.).

International Nuclear Information System (INIS)

We reported three cases of acute intracranial tuberculosis including miliary tuberculosis, basal meningitis, tuberculomas and neuritis of cranial nerves. All patients had native and contrast enhanced CT and MRI scans. MRI revealed more granulomas and a better imaging contrast in the detection of basal meningitis. Neuritis was diagnosed only with the MRI. MRI scans should be prefered as the imaging procedure in clinically presumed intracranial tuberculosis. (orig.).

UK PubMed Central (United Kingdom)

To assess which specific morphologic features, enhancement patterns, or pharmacokinetic parameters on breast Magnetic Resonance Imaging (MRI) could predict a false-negative outcome of Proton...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The method of double microwave--radio-frequency resonance has been used to obtain spectra of the 2/sub 11/reverse arrow2/sub 12/ and 3/sub 21/reverse arrow3/sub 22/ transitions in HCOOD, DCOOH, and HCOOH molecules. The constants of the quadrupole bond of the deuterons have been determined, magnetic interactions being taken into acocunt. A comparison with results of previous studies is given.

International Nuclear Information System (INIS)

A review of the information on the electron and phonon spectra in the A-15 compounds and Chevrel phase superconductors obtained from nuclear magnetic resonance, heat capacity, and Moessbauer effect experiments is presented. Relationships of the Fermi energy electrons and the soft phonons to the strength of the electron-phonon interaction are discussed.

Energy Technology Data Exchange (ETDEWEB)

We have measured, by {sup 1}H and {sup 13}C nuclear magnetic resonance (NMR), the percent deuteration, the tacticity and the purity of several polymers and one solvent used in the preparation of microcellular foams. The percent deuteration was measured for polystyrene, polyacrylonitrile and polyethylene. The tacticities of polystyrene and polyacrylonitrile were determined. The purity and degradation products of polyacrylonitrile and maleic anhydride were examined. This report documents the experimental procedures and results of these measurements.

CERN Document Server

Observations show the ubiquitous presence of propagating magnetohydrodynamic (MHD) kink waves in the solar atmosphere. Waves and flows are often observed simultaneously. Due to plasma inhomogeneity in the perpendicular direction to the magnetic field, kink waves are spatially damped by resonant absorption. The presence of flow may affect the wave spatial damping. Here, we investigate the effect of longitudinal background flow on the propagation and spatial damping of resonant kink waves in transversely nonuniform magnetic flux tubes. We combine approximate analytical theory with numerical investigation. The analytical theory uses the thin tube (TT) and thin boundary (TB) approximations to obtain expressions for the wavelength and the damping length. Numerically, we verify the previously obtained analytical expressions by means of the full solution of the resistive MHD eigenvalue problem beyond the TT ...

UK PubMed Central (United Kingdom)

Some laboratory experiments have suggested that power-frequency electric and magnetic fields (EMF) may be capable of influencing calcium efflux from cell membranes, pineal function, and circadian rhythms....Full Text Available

International Nuclear Information System (INIS)

"1"7"5Ta and "1"7"7Ta nuclei were oriented at low temperature as dilute impurities in Fe. The magnetic hyperfine splitting frequencies #nu#="+#mu#B sub(HF)/Ih"+ of the "1"7"5Ta and "1"7"7Ta ground states have been measured to be 320.45(11) and 317.552(55) MHz by using the technique of NMR-ON. Taking the known hyperfine field of "1"8"1Ta in Fe, the magneticmoments have been deduced: "+#mu#("1"7"5Ta, 7/2"+)"+=2.270(45) and "+#mu#("1"7"7Ta, 7/2"+)"+=2.250(45)#mu# sub(N). These values of the magnetic moments are discussed in the framework of the rotational model. (author).

International Nuclear Information System (INIS)

The symmetry properties of the Coulomb potential allow for a dynamical spin-1/2 description of any fixed n level of a hydrogenlike atom in a time-dependent sufficiently weak electric and/or magnetic field. An explicit expression for the time dependence of the l,m amplitudes pertaining to a general n level is derived. The derivation follows on purely algebraic operations. Based on the derivation, we give analytical n-independent solutions to established and proposed schemes for driving the atom into a high angular-momentum state.

Science.gov (United States)

Recent proposals have shown that a quantum degenerate gas of alkaline earth atoms can be used for a number of novel quantum computing and quantum simulation experiments. Strontium is a good candidate for such experiments because it can be controlled with high precision, as demonstrated in recent atomic clock experiments. Unfortunately, the small scattering length of strontium is not amenable to evaporative cooling techniques that are used to reach quantum degeneracy. Furthermore, increasing the scattering length of alkaline earths with a magnetic Feshbach resonance is not possible due to their spinless electronic ground state configuration. However, recent theoretical and experimental work suggests the possibility of changing scattering lengths in alkaline earths with laser light. Using this optical Feshbach resonance near strontium's narrow ^1S0->^3P1 intercombination transition might allow its scattering length to be ...

International Nuclear Information System (INIS)

Single crystals of U(Ni_1_-_xPd_x )_2Si_2 for x = 0.05, 0.10 and 0.15 have been grown. Magnetization and electrical resistivity measurements were performed in a wide range of temperatures, magnetic fields and high pressures in order to study stability of magnetic phases in the solid solutions between UNi_2Si_2 and UPd_2Si_2 with a special emphasis on the type of ground state. In UPd_2Si_2 the simple AFI-type antiferromagnetic structure of U moments is observed at low temperatures. UNi_2Si_2 adopts the uncompensated AF structure (UAF) with the ++- stacking of U moments along the c-axis and consequently this compound exhibits a spontaneous magnetization corresponding to 1/3 of the U moment. The substitution of Pd for Ni leads to a rapid decay of the spontaneous magnetization. The evolution of magnetization and electrical ...

Energy Technology Data Exchange (ETDEWEB)

The problem of thermal instability of compressible, electrically conducting couple-stress fluids in the presence of a uniform magnetic field is considered. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection, the compressibility, couple-stress, and magnetic field postpone the onset of convection. Graphs have been plotted by giving numerical values of the parameters to depict the stability characteristics. The principle of exchange of stabilities is found to be satisfied. The magnetic field introduces oscillatory modes in the system that were non-existent in its absence. The case of overstability is also studied wherein a sufficient condition for the non-existence of overstability is obtained. (orig.)

Science.gov (United States)

MAGNETIC FORMING .............. MAGNETIC INDUCTION ............ MAGNETIC MATERIALS ............ MAGNETIC MEASUREMENT .......... MAGNETIC PERMEABILITY . ...

International Nuclear Information System (INIS)

The magnetic scattering spectra of RAgSb_2 (R = Ho, Er, Tm) intermetallic compounds are measured and their crystal electric field parameters are determined using inelastic neutron scattering. It is revealed that the ground state is a nonmagnetic singlet for the HoAgSb_2 compound, a Kramers doublet with a strongly anisotropic g factor for the ErAgSb_2 compound, and a quasi-doublet (random doublet) characterized by an extremely anisotropic g factor for the TmAgSb_2 compound. The exchange interaction is estimated in the molecular field approximation. The magnetic properties of the RAgSb_2 compounds are analyzed in terms of the energy level schemes and eigenfunctions determined in this study. The calculated anisotropic magnetic susceptibilities for all compounds are in good agreement with the experimental data obtained for single crystals.

International Nuclear Information System (INIS)

In recent years, there has been a significant increase in concern over the health and safety aspects of high voltage transmission lines (HVTL). The majority of research has focused on effects directly or indirectly involved with the central nervous system, including physiological, ultrastructural, and biochemical alterations, changes in blood composition, behaviour, reproduction, and development. Several recent epidemiological reports have presented preliminary data suggesting an increase in the incidence of cancer among children and adults exposed to magnetic fields through living close to various types of electrical power lines or devices. With the increase in environmental concerns there has been a concomitant consideration of biological effects and health implications related to presently existing HVTL and those planned in the future. It was concluded that the electric and magnetic field strengths ...

Energy Technology Data Exchange (ETDEWEB)

Electron trapping in crossed electric and magnetic fields is an important mechanism by which electrical discharges can develop in low pressure gases. The authors report observations of discharges produced by this mechanism around a spherical anode in two space simulation chambers, namely the Space Plasma Interaction Experiment (SPIE) at the University of Maryland, and the NASA-Lewis B-2 chamber. They have identified two types of discharges in these experiments. In the B-2 chamber, the breakdown takes the form of a runaway dischage with spherical topology, limited only by the ability of the power supply to provide the current. In the SPIE chamber this type of discharge also occurs, in addition to a low current toroidal discharge which is observed at higher magnetic fields. They present measurements of both types of discharge and show how the trapping effect of the magnetic field ...

Energy Technology Data Exchange (ETDEWEB)

Concerns are sometimes expressed about an alleged link between exposure to the extremely low frequency electromagnetic fields occurring in proximity to electricity networks or equipment. Transmission lines are specifically mentioned. The underlying physical mechanisms are described by which electric and magnetic fields exist, with particular reference to high voltage transmission lines. Epidemiological and laboratory studies are the two approaches used in research into the subject and the shortcomings inherent in many such studies and the inconsistencies in the results are mentioned. Some of the more recent epidemiological studies are referred to, also the possible interaction mechanisms between fields and the human body. The work of certain international and national bodies which were established to review the results of research into the alleged association between electromagnetic fields and ill-health are reported. ...

International Nuclear Information System (INIS)

Structure and magnetic properties of UNi_1_0_-_xFe_xSi_2 intermetallics and "2"9Si nuclear magnetic resonance (NMR) in UNi_1_0Si_2 are investigated in a wide temperature range. Solid solutions in the exactly single-phase tetragonal form, ThMn_1_2 type, exist for x<2. The Ni and Fe atoms occupy the 8(f), 8(i) and 8(j) positions statistically, whereas the U atoms occupy the 2(a) and the Si atoms the 8(j) sites. The lattice parameters roughly follow Vegard's law. The magnetic susceptibility does not exhibit Curie-Weiss behaviour and, at about 630 K, an anomaly in the temperature dependence is observed. At low temperature, other anomalies are observed at 32 K and 45 K, for x=0.5 and 1.0 respectively. These low temperature anomalies are probably connected with magnetic ordering of a ferromagnetic character, whereas that at 630 K might result from the superparamagnetic state of Ni. Two ...

International Nuclear Information System (INIS)

Ge pre-amorphisation step is used to reduce the high diffusivity and the transient-enhanced diffusion of boron implanted in silicon. The aim of the process is to obtain shallow P"+N junctions. The pre-amorphisation step was performed under different conditions (in ambient temperature and in nitrogen). Following the rapid thermal annealing step, end of range (EOR) defects appear at the amorphous-crystalline interface. These defects could influence the electrical characteristics of the P"+N junctions. An experimental study concerning three samples has been performed without and under a magnetic field of 800 G. The magnetic susceptibility was essentially observed in the case of the reverse current. The impact of the magnetic field, studied by varying the sample temperature, permits us to show an increase of the magnetic susceptibility when the defects present in such structures are ...

Energy Technology Data Exchange (ETDEWEB)

We have performed inelastic neutron scattering (INS) experiments on CeRh{sub 3}B{sub 2} at various temperatures to obtain direct information on the crystal electric field (CEF) in this compound, which exhibits some very peculiar magnetic properties for a Ce system: it is ferromagnetic with an unusually high Curie temperature (115 K), which contrasts with a strongly reduced and anisotropic magnetization (0.4 {mu}{sub B}/fu within the c-plane of the hexagonal structure). Measurements with high incident energies show only one well defined magnetic excitation around 150 meV, its exact position varying with the temperature. These results, combined with our previous data of magnetization and magnetic form factor, have permitted us to determine the CEF energy level scheme taking into account the two J multiplets of the Ce{sup 3+} ion. Information on the ground state ...

International Nuclear Information System (INIS)

The authors compared unenhanced and contrast-enhanced fast MRI and Computerized Tomography in the detection of liver metastases. Eleven patients with single or multiple hepatic lesions (42 in all) were submitted to V and magnetic resonance studies; T1- and T2- weighted TSE, T2-weighted TSE with fat suppression, unenhanced breath-hold TFE and early or delayed enhanced breath-hold TFE images were acquired with a 1.5 T superconductive magnet (Philips NT). The quantitative analysis of all magnetic resonance images was performed for contrast/noise ratio (CNR) and number of detected lesions; magnetic resonance and Computerized Tomography images were also compared qualitatively for lesion conspicuity, anatomical structure identification and artifacts. The results were compared with Student's test. Early enhanced breath-hold TFE was statistically ...

British Library Electronic Table of Contents (United Kingdom)

Polymer insulating materials used in radioactive environments are subjected to a risk of surface degradation caused by tracking. The tracking behavior becomes more complex with the presence of magnetic field. This paper presents investigation of tracking failure of gamma-ray irradiated polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) under magnetic field. The samples were irradiated in air up to 100 kGy and then up to 1000 kGy with dose rate of 10 kGy/h by using a 60Co gamma-source. Magnetic field Formula Not Shown with flux density of 250 mT was assembled perpendicularly to electric field Formula Not Shown , which gave rise to relative angle between Formula Not Shown and surface normal vector Formula Not Shown of 0degree, 90degree and 180degree, respectively. The experi...

Energy Technology Data Exchange (ETDEWEB)

The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd{sub 2}Si{sub 2}. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of {rho}(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).

DEFF Research Database (Denmark)

The tidal motion of the ocean water through the ambient magnetic field, generates secondary electric field. This motionally induced electric field can be detected in the sea or inland and has a potential for electrical soundings of the Earth. A first goal of the paper is to gain an understanding of the global distribution of the electric signal due to tidal ocean flow. We simulate the electric signals for two tidal constituents - lunar semidiurnal (M2) and diurnal (O1) tides. We assume a realistic Earth's conductivity model with a surface thin shell and 1-D mantle underneath. Simulations demonstrate that in some coastal regions the amplitudes of the electric field can reach 100 mV/km and 10 mV/km for M2 and O1 tides respectively. The changes of lithosphere resistance produce detectable changes in the tidal electric ...

Energy Technology Data Exchange (ETDEWEB)

The force exerted on the rotor by an active magnetic bearing (AMB) is determined by the current flow in the magnet coils. This force can be controlled very precisely, making magnetic bearings a potential benefit for grinding, where cutting forces act as external disturbances on the shaft, resulting in degraded part finish. It is possible to achieve precise shaft positioning, reduce vibration of the shaft caused by external disturbances, and even damp out resonant modes. Adaptive control is an appealing approach for these systems because the controller can tune itself to account for an unknown periodic disturbance, such as cutting or grinding forces, injected into the system. In this paper the authors show how one adaptive control algorithm can be applied to an AMB system with a periodic disturbance applied to the rotor. An adaptive algorithm was developed and implemented in both simulation and hardware, ...

Energy Technology Data Exchange (ETDEWEB)

Sweden is facing a re-structured electricity market beginning January 1, 1996, implying full competition in the purchasing and selling of electricity. The transmission and distribution of electricity will remain as a franchised monopoly and this business has to be strictly separated from the electricity trading. In the monopolistic environment, pricing of electricity has been based on more or less relevant costs and a resonable rate of return. The energy charges have reflected the system short range marginal costs while the demand and fixed charges have been adapted to give a total cost level corresponding to the system average cost. Tariffs of this type, known as time-of-use tariffs, have stimulated peak shaving during peak load (high cost hours) and valley filling during low load (low cost hours), increasing the load factor. Restructuring will influence the ...

International Nuclear Information System (INIS)

We examined whether proton magnetic resonance spectroscopy (MRS) could provide accurate information on histological grade and cell proliferation in astrocytomas. We studied 23 patients with astrocytomas: five grade II, 10 grade III and eight with grade IV (glioblastoma multiforme). We performed proton MRS and determined the Ki-67 labeling index (LI), a tumour proliferation marker, in the same areas of the astrocytomas, and examined the statistical relationship between proton MRS and Ki-67 LI. The N-acetylaspartate (NAA)/creatine-phosphocreatine (Cr) and NAA/choline (Cho)-containing compound ratios were always significantly lower and the Cho/Cr ratios significantly higher than those for normal brain. The Cho/Cr ratio correlated positively and the NAA/Cho ratio inversely with Ki-67 LI. These findings suggest that the Cho signal in proton MRS reflects cellular proliferation. In Kaplan-Meier survival analysis, there was no significant difference ...

International Nuclear Information System (INIS)

Central Nervous System (CNS) involvement, whether primary by the Human Immunodeficiency Virus - HIV - itself, or secondary (toxoplasmosis or lymphoma) is remarkably frequent in AIDS, in 40 to 70% of cases, depending upon the author. In order to study the natural history of this illness, a cohort of 25 asymptomatic seropositive patients have been established. Every 6 months these patients undergo biological and clinical examinations, as well as Magnetic Resonance brain scans. After two examinations at a 6 month's interval, the first results are reported. Out of these 25 cases, 9 present anomalies: One patient with diffuse cerebral atrophy and 8 others with high signal intensity areas on T2 weighted sequences, like those of the Multiple Sclerosis. No relationship could be demonstrated between the existence of these lesions and various criteria such as age, sex, risk factors and T4 cells count. The nature of these lesions is not lear. They ...

International Nuclear Information System (INIS)

Artifical valve prostheses are often regarded as a contraindication for magnetic resonance imaging (MRI), although preliminary in vitro studies suggested, that patients with these metallic implants might safely undergo MR examination. This study reports on the experience with a group of 89 patients with 100 heart valve prostheses who were examined by spin-echo MR and gradient-echo MR. MR examination was performed in all patients without complications. The spin-echo sequence showed advantages in the depiction of anatomical structures like paravalvular abcesses. Anatomical structures adjacent to the artificial valve were clearly visivle and the metal components of the valves showes no or only small artifacts. Artifacts were accentuated when using gradient-echo sequences. Gradient-echo sequences provided valuable information regarding the presence of valvular insufficiency. Physiological valvular regurgitation was easy to differentiate from ...

International Nuclear Information System (INIS)

Fourteen patients with cervical hip fractures were treated with internal fixation using titanium screws. The femoral head vitality was evaluated with "9"9Tc"m-MDP scintigraphy and scintimetry within 2 weeks postoperatively and by serial low field magnetic resonance imaging (MR). Two patients with reduced radionuclide uptake (femoral head ratio =# 1.0), MR revealed a focal decrease of the signal intensity in the femoral head or neck at 2, 3 and 7 months after fracture, respectively. The radiographs in one of these patients were normal at 7 months after fracture. The second one showed signs of necrosis at 16 months and the last one developed delayed/non-union. With a non-ferromagnetic osteosynthesis the healing course after femoral neck fracture can be studied with low field MR equipment without disturbing artifacts. The time period between ischaemia and definite abnormalities on MR may embrace several months. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Solid-state nuclear magnetic resonance (NMR) has been used to explore the nanometer-scale structure of Nafion, the widely used fuel cell membrane, and its composites. We have shown that solid-state NMR can characterize chemical structure and composition, domain size and morphology, internuclear distances, molecular dynamics, etc. The newly-developed water channel model of Nafion has been confirmed, and important characteristic length-scales established. Nafion-based organic and inorganic composites with special properties have also been characterized and their structures elucidated. The morphology of Nafion varies with hydration level, and is reflected in the changes in surface-to-volume (S/V) ratio of the polymer obtained by small-angle X-ray scattering (SAXS). The S/V ratios of different Nafion models have been evaluated numerically. It has been found that only the water channel model gives the measured S/V ratios in the normal hydration ...

International Nuclear Information System (INIS)

High-resolution proton nuclear magnetic resonance spectroscopy has been used to investigate the molecular mechanism of the Bohr effect of human normal adult hemoglobin in the presence of two allosteric effectors, i.e., chloride and inorganic phosphate ions. The individual hydrogen ion equilibria of 22-26 histidyl residues of hemoglobin have been measured in anion-free 0.1 M HEPES buffer and in the presence of 0.18 M chloride or 0.1 M inorganic phosphate ions in both deoxy and carbonmonoxy forms. The results indicate that the #beta#2-histidyl residues are strong binding sites for chloride and inorganic phosphate ions in hemoglobin. The affinity of the #beta#2-histidyl residues for these anions is larger in the deoxy than in the carbonmonoxy form. Nevertheless, the contribution of these histidyl residues to the anion Bohr effect is small due to their low pK value in deoxyhemoglobin in anion-free solvents. The interactions of chloride and ...

Energy Technology Data Exchange (ETDEWEB)

This progress report consists of an article, the abstract of which follows, and apparently the references and vita from a proposal. A review of perturbation diagnostics applied to microwave resonant cavity discharges is presented. The classical microwave perturbation technique examines the shift in the resonant frequency and cavity quality factor of the resonant cavity caused by low electron density discharges. However, modifications presented here allow the analysis to be applied to discharges with electron densities beyond the limit predicted by perturbation theory. An {open_quote}exact{close_quote} perturbation analysis is presented which models the discharge as a separate dielectric, thereby removing the restrictions on electron density imposed by the classical technique. The {open_quote}exact{close_quote} method also uses measurements of the shifts in the resonant conditions of the cavity. Thirdly, ...

Energy Technology Data Exchange (ETDEWEB)

The authors present a guide to the imaging of facial fractures. It is illustrated with conventional radiographs and computed tomograms; the magnetic resonance images primarily suggest the potential applications of this technique. This book provides a source of imaging information on facial trauma. A section on pertinent anatomy is followed by a systematic discussion of the common isolated and complex facial fractures. Perspectives are offered on some commonly seen but infrequently described relationships, such as the tripod-LeFort II association. Consideration is also given to related soft-tissue injuries. The book includes a brief chapter on the type and utility of supplementary imaging studies in the evaluation of those intracranial injuries that may occur concurrently.

British Library Electronic Table of Contents (United Kingdom)

We have prepared a series of novel gemini surfactants having ester bonds in their structures. These surfactants possess two identical hydrophilic polyethylene glycol moieties, two hydrophobic alkyl group moieties, and an anionic spacer. The structures of these compounds were confirmed through infrared and nuclear magnetic resonance spectroscopic and elemental analyses. The novel gemini surfactants exhibit excellent surface activity in terms of their surface tension, low-foaming, wetting power, and fluorescence properties. The presence of the ester linkages made these structures cleavable surfactants.

Energy Technology Data Exchange (ETDEWEB)

To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

Energy Technology Data Exchange (ETDEWEB)

The central nervous system is involved in 10-20% of cases in Lyme disease. The neurological symptoms, time course of the disease and imaging findings are multifaceted. We report two patients with cervical radiculitis. Magnetic resonance imaging revealed strong enhancement of the cervical nerve roots on contrast-enhanced T1-weighted images. These imaging patterns of borrelia-associated radiculitis have not been reported before. Knowledge of these imaging features may help to diagnose neuroborreliosis, which presents with non-specific symptoms. (orig.)

International Nuclear Information System (INIS)

In order to understand the physical processes concerned with the selective heating by ion cyclotron resonance and with the subsequent collection of heated particles, experiments were carried out with the extraction of lithium samples, enriched with "6Li isotopes. Probe and integral extractors allow to collect enriched Li at the end of the selective heating region. Surface density distribution on the collector and local isotopic content of lithium are measured, as a function of the screen height and the retarding potential. Dependence of the collected amount of lithium and of its isotopic content on the value of the magnetic field is also measured. 4 figs., 2 tabs., 5 refs.

International Nuclear Information System (INIS)

A 3"1/_2-year-old child developed unilateral diaphragmatic paralysis after chest drain insertion. Plain chest X-ray demonstrated paravertebral positioning of the chest-tube tip, and magnetic resonance imaging revealed hematomas in the region of the chest-tube tip and the phrenic nerve fibers. The trauma to the phrenic nerve was apparently secondary to malposition of the chest tube. This is a rare complication and has been reported mainly in neonates. Radiologists should notify the treating physicians that the correct position of a chest drain tip is at least 2 cm distant from the vertebrae. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The possibility of controlling the radial electric field of toroidal plasmas by injecting high energy electrons along the reversible loss cone orbit of the helical magnetic traps is investigated. It is well known that the radial electric field plays an important role in the confinement improvement scenario especially in the low collisional regime under the physics picture of neoclassical theory. For this purpose, it is made clear that the most suitable particles are transit particles, which show a transition from helically trapped orbits to blocked ones. It is also found that a parallel AC electric field launched from outside assists this transition and makes it possible for particles to penetrate deeply into the plasma. In addition we clarify that the viscosity of the plasma coupled with the helical field configuration provide a bifurcation of plasma states and its stable solution results in ...

International Nuclear Information System (INIS)

High-resolution "1H and "3"1P nuclear magnetic resonance spectroscopy has been used to investigate the binding of 2,3-diphosphoglycerate to human normal adult hemoglobin and the molecular interactions involved in the allosteric effect of the 2,3-diphosphoglycerate molecule on hemoglobin. Individual hydrogen ion NMR titration curves have been obtained for 22-26 histidyl residues of hemoglobin and for each phosphate group of 2,3-diphosphoglycerate with hemoglobin in both the deoxy and carbonmonoxy forms. The results indicate that 2,3-diphosphoglycerate binds to deoxyhemoglobin at the central cavity between the two #beta# chains and the binding involves the #beta#2-histidyl residues. Moreover, the results suggest that the binding site of 2,3-diphosphoglycerate to carbonmonoxyhemoglobin contains the same (or at least some of the same) amino acid residues responsible for binding in the deoxy form. As a result of the specific interactions with ...

Energy Technology Data Exchange (ETDEWEB)

Electromagnetic fields have been reported to cause a variety of biological effects. It has been hypothesized that many of these phenomena are mediated by a primary effect on the concentration of cytosolic free calcium ((Ca2+)i). We investigated the effects of exposure to electromagnetic fields on (Ca2+)i in HL-60 cells using the Ca2(+)-sensitive fluorescent indicator indo-1. Indo-1-loaded cell samples were exposed to a radiofrequency electromagnetic field, a static magnetic field, and a time-varying magnetic field, which were generated by a magnetic resonance imaging (MRI) unit. We found that a 23-min exposure to all three fields, in combination, induced a significant increase in (Ca2+)i of 31 +/- 8 (SE) nM (P less than 0.01, n = 13) from a basal level of 121 +/- 8 nM. Also, cells exposed to only the time-varying magnetic field had a mean (Ca2+)i that was 34 +/- 10 nM (P less than ...

British Library Electronic Table of Contents (United Kingdom)

We present the low-temperature physical properties of the polycrystalline perovskite systems La2/3A1/3Mn1-xCoxO3, A=Ca, Sr (0.5x1) including electrical resistance, magnetization, ac and dc susceptibilities. The experimental data suggest the presence of correlated ferromagnetic clusters embedded in some non-ferromagnetic matrix. The systems show semiconducting behavior and negative magnetoresistance.

Science.gov (United States)

Elastic electromagnetic form factors of nucleons are investigated for both the time-like and the space-like momenta by using the unsubtracted dispersion relation with QCD constraints. It is shown that the calculated form factors reproduce the experimental data reasonably well; they agree with recent experimental data for the neutron magnetic form factors for the space-like data obtained by the CLAS Collaboration and are compatible with the ratio of the electric and magnetic form factors for the time-like momentum obtained by the BABAR Collaboration.

Science.gov (United States)

We calculate the electromagnetic form factors of a bound proton. The chiral quark-soliton model provides the quark and antiquark substructure of the proton, which is embedded in nuclear matter. This procedure yields significant modifications of the form factors in the nuclear environment. The sea quarks are almost completely unaffected, and serve to mitigate the valence quark effect. In particular, the ratio of the isoscalar electric to the isovector magnetic form factor decreases by 20% at Q{sup 2}=1 GeV{sup 2} at nuclear density, and we do not see a strong enhancement of the magnetic moment.

Energy Technology Data Exchange (ETDEWEB)

Magnetization, specific heat, and electrical resistivity measurements were made on single crystals of the filled skutterudite compound PrOs{sub 4}As{sub 12}. Specific heat measurements indicate an electronic specific heat coefficient {gamma} {approx} 50-200 mJ/mol K{sup 2} at temperatures 10 K {le} T {le} 18 K, and {approx} 1 J/mol K{sup 2} for t {le} 1.6 K. Magnetization, specific heat, and electrical resistivity measurements reveal the presence of two, or possibly three, ordered phases at temperatures below {approx} 2.3 K and in fields below {approx} 3 T. The low temperature phase displays antiferromagnetic characteristics, while the nature of the ordering in the other phase(s) has yet to be determined.

International Nuclear Information System (INIS)

Measurements of the electrical conductivity, dielectric constant and magnetic susceptibility of pellets of erbium tungstate are reported for the temperature range 300 to 1000 K. The known phase transition near 600 K is in evidence in all these measurements. The conductivity data for T>600 K have been analysed in terms of an exponential relation sigma=sigmasub(0)exp(-Esub(g)/2kT), giving sigma_0=8.892x10"2ohm"-"1cm"-"1 and Esub(g)=1.52eV. There is a weak dispersion in the dielectric constant at around 10"4Hz and a rapid increase above 600 K. The high-temperature data for the susceptibility obey a Curie-Weiss law that gives a value of 9.50 Bohr magneton for Er"3"+ ions and a (ferromagnetic) Curie temperature of 160 K. (author).

Energy Technology Data Exchange (ETDEWEB)

Horizontal vibrations of elevator cars mainly occur because a car swings as roller guides installed at corners of a car frame move on a winding guide rail at high speeds. Rider comfort in high speed elevators is worsened by these vibrations. Conventional active dampers suppressing horizontal vibrations using ac servo motors make cars heavier so driving power becomes larger, and they are not easily applied to existing elevators. An active damping control method suited to super-high-speed elevators is which can solve these problems. The method suppresses vibrations by generating only enough magnetic force needed to suppress them only when vibrations of the car franc are produced. The vibrations are detected using acceleration detectors and magnets installed on left and right sides of the car frame. A computer simulator was made to analyze phenomena of car vibrations and to verify effects of the proposed magnetic damping ...

British Library Electronic Table of Contents (United Kingdom)

The fully developed electrically conducting micropolar fluid flow and heat transfer along a semi-infinite vertical porous moving plate is studied including the effect of viscous heating and in the presence of a magnetic field applied transversely to the direction of the flow. The Darcy-Brinkman-Forchheimer model which includes the effects of boundary and inertia forces is employed. The differential equations governing the problem have been transformed by a similarity transformation into a system of non-dimensional differential equations which are solved numerically by element free Galerkin method. Profiles for velocity, microrotation and temperature are presented for a wide range of plate velocity, viscosity ratio, Darcy number, Forchhimer number, magnetic field parameter, heat absorption ...

International Nuclear Information System (INIS)

A one-dimensional numerical model for the expansion of impact-produced vapor clouds is used to investigate magnetic field generation mechanisms in events such as meteor collisions with the moon. The resulting cloud properties, such as ionization fraction, electrical conductivity, radial expansion velocity, mass density, and energy density are estimated. The model is initiated with the peak shock states and pressure thresholds for incipient and complete vaporization of anorthosite lunar surface materials by iron and GA composition meteorites. The expansion of the spherical gas cloud into a vacuum was traced with a one-dimensional explicit lagrangian hydrodynamic code. The hypervelocity impact plasmas produced are found to be significant in the amplitudes and orientations of the magnetic fields generated. An ambient magnetic field could have been provided by the core dynamo, which would have interacted ...

International Nuclear Information System (INIS)

The magnetorheological suspension (MRS) brake is of the monoblock type. The main part of the electromagnetic brake is an electromagnet, between whose poles two MRS disks are placed. For distances between disks of 0.65x10"-"3 m#+-#10%, revolutions of the electric motor, coupled to the electromagnetic brake, ranging between 200 and 1600 rev/min and braking powers of up to 85 W, there are no differences in revolutions between the disks of the electromagnetic brake. For fixed revolutions of the electric motor, the revolution of the parallel disk can be modified continuously by means of the intensity of the magnetic field. In all cases, the quantity of MRS is of 0.35x10"-"3 kg.

International Nuclear Information System (INIS)

The first essential before embarking on the radiation-hardening of electrical insulation - mostly magnet coils - in any beam line application is to obtain a reliable estimate of the dose to the components. These are examples ( switchyards at SLAC and LAMPF) where the degree of hardness specified was much higher than was required. Although experience shows that the cost premium for substantial radiation - hardening is of the order of 10%, it has also become clear that well - designed beam line have negligible losses: hardening is required only in the vicinity of targets, collimators or other beam - intercepting devices. Where the beam is deliberately scraped, local shielding will minimize the associated radiation in the surroundings. Electron machines have their own special problems due to synchrotron radiation, so certainly coils and other electrical equipment should be kept away from the beam bend - plane. Because proton ...

International Nuclear Information System (INIS)

Superparamagnetic MFe23+O4 (M=Mn2+, Fe2+ and Co2+) inverse spinel ferrite (ISF) nanoparticles with narrow size distribution having average diameters of 6-8 nm were synthesized by a diol reduction of organic metals and the surface was modified to be hydrophilic by coating with succimer. Magnetic resonance imaging (MRI) contrast enhancement by dipolar coupling defined interactions between the synthesized ISFs and protons in the bulk water was investigated with initial susceptibility, magnetization and anisotropy of the succimer-coated ISFs. The relaxivity ratios, r2/r1, for MnFe2O4, Fe3O4 and CoFe2O4 were measured to be 12.2, 23.1 and 62.3, respectively, which demonstrate the potential usefulness of these magnetic nanoparticles as T2 contrast agents for MRI.

International Nuclear Information System (INIS)

The far infrared free electron laser (FEL) has been being developed since 1990 using the L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University. The first lasing was obtained in 1994 at wavelengths from 32 to 40 #mu#m. The FEL is now being modified suitable for user experiments. The wiggler with a fixed magnet gap used in the original FEL has been remodeled to make the magnet gap variable. In order to optimize the variable range of the gap, the gain and the diffraction loss were calculated. The peak gain is calculated to be 270% and the diffraction loss to be 22% at 150 #mu#m. The wavelength is expected to be variable from 25 up to at least 150 #mu#m. The two bending magnets in the optical resonator have been remodeled and the vacuum chambers with larger vertical sizes for them have been newly made so that the diffraction loss in these parts becomes smaller than ...

Energy Technology Data Exchange (ETDEWEB)

The authors report experimental results on a high gradient 17 GHz RF photocathode gun. The photocathode RF gun is a novel electron beam source intended to meet the requirements set by future high-energy linear colliders and next generation free electron lasers. A coupled pair of pillbox TM{sub 010}-like resonators is excited by sidewall coupled microwaves at 17 GHz. A picosecond ultraviolet laser pulse illuminates one wall of the structure at the axis of symmetry. Electrons are released by the photoelectric effect and are accelerated by the electric field of the microwaves in the cavity. The high frequency of operation raises the RF breakdown limit allowing strong electric fields to be used. In turn, the intense fields result in rapid acceleration of the electrons to relativistic speeds and reduced space charge induced emittance growth.

Energy Technology Data Exchange (ETDEWEB)

Generation of anomalous resistivity and dynamical development of collisionless reconnection in the vicinity of a magnetically neutral sheet are investigated by means of a three-dimensional particle simulation. For no external driving source, two different types of plasma instabilities are excited in the current layer. The lower hybrid drift instability (LHDI) is observed to grow in the periphery of current layer in an early period, while a drift kink instability (DKI) is triggered at the neutral sheet in a late period as a result of the nonlinear deformation of the current sheet by the LHDI. A reconnection electric field grows at the neutral sheet in accordance with the excitation of the DKI. When an external driving field exists, the convective electric field penetrates into the current layer through the particle kinetic effect and collisionless reconnection is triggered by the convective electric ...

Science.gov (United States)

Electric utilities have been surprised by recent opposition to the construction of very-high-voltage transmission lines, which met with little resistance in the past. Concerns over health and safety factors are associated with the increase in the number of such lines, although their presence has always been an inconvenience and a hazard for those living and working in the immediate vicinity. The new lines present additional hazards due to the continuous flow of small electric currents and the charges that build up in the area of the towers and lines. The lines are also a threat to persons wearing cardiac pacemakers. There is experimental evidence from the Soviet Union and the U.S. that electric and magnetic fields at the frequencies of such power lines can have serious biological effects on growth rates and the functioning of the central nervous system. Full disclosure that possible risks are involved ...

Energy Technology Data Exchange (ETDEWEB)

The electronic structure of the C15, or cubic-Laves-phase material, UAl/sub 2/ has been calculated using the linearized relativistic augmented-plane-wave method. The anomalous behavior of the electrical resistivity, specific heat, and magnetic susceptibility can be explained by the fine structure of the density of states near the Fermi energy alone, without the necessity of the introduction of drastic spin fluctuations or many-body effects.

Energy Technology Data Exchange (ETDEWEB)

The bibliography contains citations concerning the properties of tantalum and tantalum compound films formed by sputtering techniques. Topics include processes, and electrical, magnetic, and dielectric properties of the sputtered films. Tantalum compounds studied include nitrates, oxides, and aluminides. The structural properties of sputtered films are also discussed. (Contains a minimum of 105 citations and includes a subject term index and title list.)

International Nuclear Information System (INIS)

Field reversed configuration (FRC) is a prospective high ? magnetic system for high efficiency D- 3He fusion reactor. Self-consistent FRC plasma profiles and static electric field for reactor calculations are discussed in framework of the model including flow equilibrium and collisionless transport equations. The extrapolations to reactor regimes of plasma confinement scaling laws are considered.

Energy Technology Data Exchange (ETDEWEB)

The hyperfine structure of Am atoms was investigated in an atomic beam by laser spectroscopy. The observed splittings were evaluated with respect to the magnetic dipole and electric quadrupole moments of /sup 242m/Am. The results are: ..mu../sub I/(/sup 242m/Am) = +0.97(5) nm, Q(/sup 242m/Am) = +6.5(2.0) b.

International Nuclear Information System (INIS)

In in-service inspection of steam-generator tubes, the need for reproducibility of the measurement results and for comparison of these results over two successive inspections has led EDF to specify the main characteristics of the eddy-current probes and to design equipment to measure them. This equipment is presented here and the electrical and magnetic results are correlated with those obtained by testing tubes with reference defects.

UK PubMed Central (United Kingdom)

The aim of the study was to investigate the possible acute effects of exposure to electric and magnetic fields. Twenty six experienced linesmen, aged 25 to 52, were studied during two working days while...Full Text Available

International Nuclear Information System (INIS)

As part of the licensing process to construct a new 230 kV transmission line on an existing right-of-way in Manitoba, an electrical effects study was conducted in 1998. The study was part of the environmental assessment program crucial in obtaining government approval to construct the line. Some residents living adjacent to the new transmission circuit expressed concerns about alleged adverse health effects associated with long-term exposure to magnetic fields from high voltage transmission lines. In order to verify the accuracy of the predicted magnetic field levels submitted to the regulatory body in the the electrical effects study and to instill confidence in the residents of the affected communities, a three-year magnetic monitoring project was conducted between 2003 and 2005 along the right-of-way after the new 230kV transmission line was energized by Manitoba Hydro. This ...

International Nuclear Information System (INIS)

The marked difference between the intra- and extracellular "3"1P NMR chemical shifts of various phosphoryl compounds when added to a red cell suspension may be largely understood in terms of the effects of hemoglobin on the "3"1P NMR chemical shifts. The presence of [oxy- or (carbonmonoxy)-] hemoglobin inside the red cell causes the bulk magnetic susceptibility of the cell cytoplasm to be significantly less than that of the external solution. This difference is sufficient to account for the difference in the intra- and extracellular chemical shifts of the two phosphate esters trimethyl phosphate and triethyl phosphate. However, in the case of the compounds dimethyl methylphosphonate, diethyl methylphosphonate, and trimethylphosphine oxide as well as the hypophosphite, phenylphosphinate, and diphenylphosphinate ions, hemoglobin exerts an additional, much larger, effect, causing the "3"1P NMR resonances to shift to lower frequency in a manner ...

International Nuclear Information System (INIS)

The present article outlines major features of the free electron laser (FEL) and reviews research and development of FEL. Relations among the oscillation frequency, electron beam parameters and wiggler parameters, the physical mechanism of amplification and the physical process of saturation are discussed to identify the difference between FEL and other lasers. The report also outlines techniques for accelerators which are used to generate high-quality, high-energy electron beams required for FEL experiments. Techniques to achieve a short wavelength, high output and high efficiency, and applications of FEL are also discussed. FEL consists of an electron accelerator, wiggler and optical resonator. In FEL, electron beams with a relativistic energy interact resonantly with an electromagnetic field to generate coherent electromagnetic waves. Unlike conventional lasers, FEL does not surfer from restrictions on its oscillation frequency associated ...

International Nuclear Information System (INIS)

Ternary R_2TSi_3 intermetallic compounds (R=Rare Earth, T=Transition Metal) with hexagonal AlB_2-type crystallographic structure are known because of their interesting physical properties. Pr_2PdSi_3 single crystals were grown by a vertical floating zone method. The compound exhibits congruent melting behavior at a liquidus temperature of about 1770 C. Single crystalline samples show a huge anisotropy at low temperatures due to the crystal electric field effect and order antiferromagnetically below the Neel temperature T_N=2.17 K. This value approximately obeys the linear de Gennes scaling for this class of compounds. The [001] orientation was identified as the magnetic easy axis at room temperature. At lower temperature (#approx#20 K) magnetic easy and hard axes interchange with each other. Two additional magnetic phase transitions were observed at temperatures below 1 K.

British Library Electronic Table of Contents (United Kingdom)

Objective To investigate value of magnetic resonance cholangiopancreatography (MRCP) using oral diluted gadolinium (Gd)-diethylenetriamine penta-acetic acid (DTPA) as negative contrast materials in diagnosis of juxtapapillary duodenal diverticulum with atypical imaging features. Methods Nineteen patients with juxtapapillary duodenal diverticula of which imaging findings were atypical underwent MRCP using oral diluted Gd-DTPA as negative contrast materials after conventional MRCP without any oral contrast materials. Results Twenty diverticula were revealed in the 19 patients. At conventional MRCP, the diverticula appeared as rounded lesion with high signal intensity. After oral administration of diluted Gd-DTPA, they disappeared at MRCP. These entities were diagnosed as duodenal diverticula...

British Library Electronic Table of Contents (United Kingdom)

There is evidence that aged normal subjects have more difficulty in achieving automaticity than young subjects. The underlying central neural mechanism for this phenomenon is unclear. In the present study, functional magnetic resonance imaging (fMRI) was used to investigate the effect of normal ageing on automaticity. Aged healthy subjects were asked to practice self-initiated, self-paced, memorized sequential finger movements with different complexity until they could perform the tasks automatically. Automaticity was evaluated by having subjects perform a secondary task simultaneously with the sequential movements. Although it took more time, most aged subjects eventually performed the tasks automatically at the same level as the young subjects. Functional MRI results showed that, for bot...

CERN Document Server

We have monitored a Type II outburst of the Be/X-ray binary MXB 0656-072 in a series of pointed RXTE observations during October through December 2003. The source spectrum shows a cyclotron resonance scattering feature at 32.8 +/- 0.5 keV, corresponding to a magnetic field strength of (3.67 +/- 0.06) x 10^12 G and is stable through the outburst and over the pulsar spin phase. The pulsar, with an average pulse period of 160.4 +/- 0.4 s, shows a spin-up of 0.45 s over the duration of the outburst. From optical data, the source distance is estimated to be 3.9 +/- 0.1 kpc and this is used to estimate the X-ray luminosity and a theoretical prediction of the pulsar spin-up during the outburst.

British Library Electronic Table of Contents (United Kingdom)

Study Type - Therapy (case series)Level of Evidence 4 OBJECTIVE To present our experience of retroperitoneoscopic partial adrenalectomy (RPA) for small adrenal tumours, as with modern imaging methods small adrenal lesions are being diagnosed more commonly, and retroperitoneoscopic adrenal surgery for small adrenal tumours (PATIENTS AND METHODS We retrospectively reviewed the records of 389 consecutive retroperitoneoscopic adrenalectomies from September 2005 to December 2008, 88 of which were small adrenal tumours and treated by RPA. Ultrasonography and computed tomography (CT) were used in all patients before RPA, and magnetic resonance imaging or positron emission tomography/CT in some patients. We used RPA for adrenal tumours and total adrenalectomy for adrenal cancer. During the surgery...

British Library Electronic Table of Contents (United Kingdom)

In order to investigate the antioxidant properties of the polysaccharides from the brown alga Sargassum fusiforme, the crude polysaccharides from S. fusiforme (SFPS) were extracted in hot water, and the lipid peroxidation inhibition assay exhibited that SFPS possessed a potential antioxidant activity. Hence, two purely polymeric fractions, SFPS-1 and SFPS-2 were isolated by the column of DEAE (2-diethylaminoethanol)-Sepharose Fast Flow, with their molecular weights of 51.4 and 30.3 kDa determined by high performance gel permeation chromatography (HPGPC). They were preliminarily characterized using chemical analysis in combination of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and found to contain large amounts of uronic acids and ?-glycosidical linkages. The antioxida...

International Nuclear Information System (INIS)

Positron emission tomography (PET) is the gold standard for non-invasive assessment of myocardial viability and allows accurate detection of coronary artery disease by assessment of myocardial perfusion. Magnetic resonance imaging (MRI) provides high resolution anatomical images that allow accurate evaluation of ventricular structure and function together with detection of myocardial infarction. Potential hybrid PET/MR tomography may potentially facilitate the combination of information from these imaging modalities in cardiology. Furthermore, the combination of anatomical MRI images with the high sensitivity of PET for detecting molecular targets may extent the application of these modalities to the characterization of atherosclerotic plaques and to the evaluation of angiogenetic or stem cell therapies, for example. This article reviews studies using MRI and PET in parallel to compare their performance in cardiac applications together with the ...

International Nuclear Information System (INIS)

We studied age-related microstructural changes in the subcortical white matter from adolescence to middle age in 16 healthy male subjects (age range: 12 to 47 years) using diffusion-weighted magnetic resonance (MR) imaging (DWI). Mean diffusivity (MD) of subcortical white matter was mapped onto the overlying cortical surface using our original method. The mean MD values within 76 cortical regions were measured using atlas-based gray matter segmentation and then correlated with age. A significant negative correlation with age was observed in subcortical MD values in several cortical regions, primarily over the bilateral temporal and occipital lobes. Our results demonstrated subcortical microstructural change in postadolescence that may reflect continuing myelination. (author)

British Library Electronic Table of Contents (United Kingdom)

Aim To determine the fate and clinical implication of large (?2cm), non-hypervascular nodules depicted on magnetic resonance imaging (MRI) in the cirrhotic liver. Materials and methods In 21 patients with cirrhosis (14 hepatitis B, two ethanol abuse, four cryptogenic, one Wilson's disease), 25 large (?2cm in the longest dimension) non-hypervascular nodules were identified on dynamic MRI. The implications for diagnosis of the initial size, contour, and signal characteristics on MRI in addition to patients' age and cause of cirrhosis were assessed in our analysis. Results Twelve (75%) out of 16 lesions were malignant or potentially-malignant from 14 hepatitis B patients, while seven (78%) of the nine lesions from other patients were benign (p=0.016). The mean age of the patients who ha...

International Nuclear Information System (INIS)

The aim of this review is to evaluate the role of inflammatory spine disease in patients with chronic back pain. The contribution of imaging modalities for the diagnostic evaluation of back pain is discussed. A systematic literature search based on the classification of seronegative spondyloarthropathies and rheumatoid arthritis was performed. The results of this search and the experiences in a large collective of rheumatological patients are analyzed. The prevalence of rheumatoid arthritis (1-2%) is comparable to that of spondyloarthropathies (1.9%). The etiology of these entities is not fully elucidated. Magnetic resonance imaging is increasingly used for early detection and surveillance of therapy with TNF-#alpha# antagonists. Bone marrow edema, which is only detectable with MRI, represents an early sign of inflammation. Therapy with TNF-#alpha# antagonists is based on clinical and laboratory criteria, and signs of inflammation in MRI. MRI ...

DEFF Research Database (Denmark)

The determination of conformational preferences in unfolded and disordered proteins is an important challenge in structural biology. We here describe an algorithm to optimize energy functions for the simulation of unfolded proteins. The procedure is based on the maximum likelihood principle and employs a fast and efficient gradient descent method to find the set of parameters of the energy function that best explain the experimental data. We first validate the method by using synthetic reference data, and subsequently apply the algorithms to data from nuclear magnetic resonance spin-labeling experiments on the Delta 131 Delta fragment of Staphylococcal nuclease. A significant strength of the procedure that we present is that it directly uses experimental data to optimize the energy parameters, without relying on the availability of high resolution structures. The procedure is fully general and can be applied to a range of experimental data and ...

British Library Electronic Table of Contents (United Kingdom)

Summary Humans discount the value of future rewards over time. Here we show using functional magnetic resonance imaging (fMRI) and neural coupling analyses that episodic future thinking reduces the rate of delay discounting through a modulation of neural decision-making and episodic future thinking networks. In addition to a standard control condition, real subject-specific episodic event cues were presented during a delay discounting task. Spontaneous episodic imagery during cue processing predicted how much subjects changed their preferences toward more future-minded choice behavior. Neural valuation signals in the anterior cingulate cortex and functional coupling of this region with hippocampus and amygdala predicted the degree to which future thinking modulated individual preference fu...

British Library Electronic Table of Contents (United Kingdom)

There are no specific diagnostic tests or a gold standard method for measuring disease activity and outcome in spondyloarthropathies (SpA). Many different methods have been developed to assess the signs and symptoms in SpA. The aim of this study was to evaluate the value of scintigraphy, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and Bath Ankilosing Spondylitis Disease Activity Index (BASDAI) in the evaluation of disease activity in early axial SpA diagnosed with magnetic resonance imaging (MRI). Thirty early MRI-positive axial SpA patients (23 males, 7 females) with a median age of 35 (18?55) years and a median duration of inflammatory low back pain of 24 (8?60) months were included in the study. In the patients with sacroiliitis, the sensitivity, specificity, and pos...

Energy Technology Data Exchange (ETDEWEB)

MRI is a powerful diagnostic modality of expanding availability. Equipment and installation amount to nearly $2M per site. An important component of diagnostic efficacy is not just equipment costs but also replacement costs, which for x-ray CT amount to 14-20% of the purchase cost per year; and in the early years of that technology reached 30-50%. The authors show how design choices made during the RandD stages of MRI development have allowed them to improve system performance parameters such as data reconstruction, archiving and display speeds, computational capabilities, operator interfaces, imaging sequence flexibility and signal-to-noise levels. Over the last four years these improvements have been made at a retrofit cost well below the target of 6-7% of the purchase price per year.

Energy Technology Data Exchange (ETDEWEB)

Brain tumor was diagnosed by computer tomography or magnetic resonance imaging in 100 children aged 0 to 19 years. They consecutively underwent primary surgical treatment during the years 1984 to 1988. Non-neoplastic lesions and operations for residual tumors are not included. 54 tumors were localized supratentorially. 72% of these were benign og low grade malignancies. 46 tumors had an infratentorial localication. 59% of these were high grade malignancies. Children tolerate major-neurosurgical procedures better than adults and restitution is usually favourable. 42 children with high grade malignancies underwent postoperative radiotherpy. Per- and postoperative mortality in this series was 1%. 80 children are alive. 62 of these are in excellent condition after a median observation time of 40 months. 10 refs.

British Library Electronic Table of Contents (United Kingdom)

Nuclear magnetic resonance (NMR) techniques coupled with multivariate data analysis were used to conduct monitoring of biochemical changes of black raspberry fruits at different stages of maturation and under various extraction and NMR dissolution solvent conditions: extraction with 50% methanol and D"2O as an NMR dissolution solvent, extraction with 50% methanol and 50% methanol-d"4 as an NMR dissolution solvent, and extraction with 100% ethyl acetate and 100% methanol-d"4 as an NMR dissolution solvent. Partial least-squares discriminant analysis reliably distinguished black raspberry fruits according to the maturation stage, whereby the relative levels of various compounds such as amino acids, organic acids, sugars and phenolic compounds were compared using analysis of variance. Sucrose ...

International Nuclear Information System (INIS)

It is well known that one of the main advantages of the high speed forming (HSF) processes is the improvement in the forming limits of the used materials.Using the Electromagnetic Forming (EMF) technology two materials have been tested with different mechanical and physical properties: the AA5754 aluminium and the AZ31B magnesium alloys.The EMF process principle can be described as follows: A significant amount of electrical energy is stored in a bank of capacitors which are suddenly discharged releasing all the stored energy. This electric discharge runs through a coil which generates an intense transient magnetic field. At the same time transient Eddy currents are induced in the electrically conductive part placed some millimetres far from the coil. Another intense magnetic field is generated due to those Eddy currents but on the opposite direction as the one generated by the ...

Energy Technology Data Exchange (ETDEWEB)

The concept of a direct energy recovery system that applies a varying magnetic field is proposed for a negative-ion-based neutral beam injection system (NNB) to heat a plasma and/or drive a plasma current in a fusion reactor. The output beam energy and power of such an NNB will be {approximately}1 MeV and {approximately}1- MW/beam-line, respectively, and nearly the same amounts of positive- and negative-ion beams remain unneutralized in an NNB by using a gas-neutralizing cell. Therefore, the output of a beam direct convertor in an NNB is a bipolar direct current (dc) electric power with close to {plus_minus} 1 MV and several amperes if a conventional electrostatic or magnetostatic field is applied for ion beam separation. However, such high-voltage dc power is difficult to handle at the point of the regeneration of the power back to a commercial electric line because a very high voltage inverter tough enough to withstand ...

Energy Technology Data Exchange (ETDEWEB)

The available experimental data on the specific heat, magnetic susceptibility, magnetization, valence, NMR Knight shift and relaxation rate, and the quadrupolar moment of YbPd{sub 2}Si{sub 2} are examined within the framework of the single-ion Anderson model. Such an analysis has previously given excellent agreement between theory and experiment for numerous other light heavy-fermion compounds, where crystalline fields do not play a dominant role. For YbPd{sub 2}Si{sub 2}, substantial crystalline-field splittings make difficult a quantitative comparison with existing exact solutions of the Anderson model. Inconsistencies with the interpretation that a nearly degenerate ground quadruplet determines the low-temperature thermodynamics are pointed out. It is concluded that at least three of the four Kramers doublets participate in the low-{ital T} properties. These three doublets should have a splitting of the order of the Kondo temperature, i.e., ...

International Nuclear Information System (INIS)

This article describes the nature of the electromagnetic waves, what they are and how do they affect us. Current concern is focused on exposure to low level power-frequency magnetic fields like microwave radiation from mobile phones and leaking microwave ovens; high power radiation from defence and airport radars; fields close to high voltage transmission lines; radio frequency fields from industrial welders and heaters and DC magnetic fields in aluminium smelters. These fields with frequency less than 300 GHz do not carry sufficient energy to break chemical bonds and it is assumed that they cannot damage cell DNA. The amount of radiation absorbed by a human exposed to far field electromagnetic radiation (EMR) depends on the orientation and size of the person. In the 30-300 MHz range it is possible to excite resonance in the whole or partial body such as the head. It is emphasised that since there are some evidence that ...

Energy Technology Data Exchange (ETDEWEB)

Isobaric contaminants are often problematical in accelerated negative ion beams for research at certain radioactive ion beam (RIB) and accelerator mass spectrometry (AMS) facilities since their presence in low-intensity rare isotopic beams seriously compromise experimental results. This article describes a non-resonant, laser-based photo-detachment apparatus for use at these facilities, which, according to calculations efficiently removes isobaric contaminants from these beams. The advantage of the system for isobaric contaminant removal over other systems proposed to date lies in its ability to efficiently capture easily transportable energetic negative ion beams with low, intermediate or high energy spreads by a superconducting solenoid magnetic field. The ability to change the diameter of captured beams by adjusting the magnetic field strength permits optimum control of the radial overlap of the laser/negative ion beam ...

Energy Technology Data Exchange (ETDEWEB)

The authors address the question of the limitations on voltage and current transfer to loads in magnetic storage systems utilizing microsecond conduction time plasma opening switches. They propose that the limitation of performance results from neutral atoms that are not entrained into the ionized material that is driven by the magnetic field of the rising generator current. Evidence in support of this proposition is gathered from experiments performed on the Ace-4 and Hawk generators. They set forth a theory to describe the effect of neutrals on the electrical performance of plasma opening switches. The neutral gas is assumed to be present in the region between the moving plasma mass and the generator, primarily in the region in which the plasma is injected initially. The essential elements of the theory are a weak photoionization source to seed the gas with a low concentration of electrons, and joule heating accompanied ...

Energy Technology Data Exchange (ETDEWEB)

I present an overview of the measurement of the proton form factors in the time-like regiun. BABAR has recently measured with great accuracy the e{sup +} e{sup -} {yields} p p-bar reaction from productiun threshold up to an energy of {approx} 4.5 GeV; finding evidence for a ratio of the electric to magnetic form factur greater than unity, contrary to expectation. In agreement with previous measurements. BABAR confirmed the steep rise uf the magnetic form factor close to the p p-bar mass threshold, suggesting the possible presence of an under-threshuld N N-bar vector state. These and uther open questiuns related to the nucleon furm factors both in the time-like and space-like region, wait for more data with different experimental techniques to be possibly solved.

Energy Technology Data Exchange (ETDEWEB)

Thermal hydraulics of a liquid metal is important to design the blanket of a magnetic confined fusion reactor. Since a liquid metal has high thermal and electrical conductivity, the flow characteristics are often different from those of an ordinary liquid like water especially in thermal convection and under a magnetic field. It is difficult to simulate such flows in a liquid metal cooled blanket by water. Flow visualization is a popular method to study thermal hydraulics. Since most of metals are visible by neutron rays, neutron radiography is available to the flow visualization of a liquid metal. The purpose of this study is to develop a visualization technique of the flow in a liquid metal by real-time neutron radiography using the tracer and the dye injection methods. A real-time thermal neutron radiography system of JRR-3M in Japan Atomic Energy Research Institute was used for the visualization test.