WorldWideScience

Sample records for magnetic giant resonances

  1. Giant right atrial myxoma: characterization with cardiac magnetic resonance imaging.

    LENUS (Irish Health Repository)

    Ridge, Carole A

    2012-02-01

    A 53-year-old woman presented to the emergency department with a 2-week history of dyspnoea and chest pain. Computed tomography pulmonary angiography was performed to exclude acute pulmonary embolism (PE). This demonstrated a large right atrial mass and no evidence of PE. Transthoracic echocardiography followed by cardiac magnetic resonance imaging confirmed a mobile right atrial mass. Surgical resection was then performed confirming a giant right atrial myxoma. We describe the typical clinical, radiologic, and pathologic features of right atrial myxoma.

  2. Magnetic resonance imaging of large and giant intracranial aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Kenichi; Saito, Akira; Nakasu, Yoko; Matsuda, Masayuki; Handa, Jyoji [Shiga University of Medical Science, Shiga (Japan); Todo, Giro

    1990-06-01

    Twelve large or giant intracranial aneurysms were studied with magnetic resonance (MR) imaging, and the findings were compared with those from computed tomographic (CT) scanning. Characteristic MR features of such aneurysms are: round, extra-axial mass with hypointensity rim; signal void, paradoxical enhancement, or even-echo rephasing due to blood flow; and laminated, eccentric thrombus with increased signal intensity when fresh, perianeurysmal hemorrhage occurs in the acute or subacute stage after aneurysmal rupture. MR imaging, however, often fails to identify or characterize the area of calcification. For the diagnosis of large or giant intracranial aneurysms, MR imaging is apparently superior to CT scanning in differentiating aneurysms from tumors, delineating the blood flow and intraluminal thrombus, and detecting the exact size of the aneurysm. It may also provide useful information concerning the growth mechanisms of aneurysms with or without thrombus formation. (author).

  3. Giant magnetic modulation of a planar, hybrid metamolecule resonance

    International Nuclear Information System (INIS)

    Gregory, Simon A; Stenning, Gavin B G; Bowden, Graham J; De Groot, Peter A J; Zheludev, Nikolay I

    2014-01-01

    Coupling magnetic elements to metamaterial structures creates hybrid metamolecules with new opportunities. Here we report on the magnetic control of a metamolecule resonance, by utilizing the interaction between a single split ring resonator (SRR) and a magnetic thin film of permalloy. To suppress eddy current shielding, the permalloy films are patterned into arrays of 30–500 μm diameter discs. Strong hybridized resonances were observed at the anticrossing between the split ring resonance and the ferromagnetic resonance (FMR) of the permalloy. In particular, it is possible to achieve 40 dB modulation of the electric (symmetric) mode of the SRR on sweeping the applied magnetic field through the SRR/FMR anticrossing. The results open the way to the design of planar metamaterials, with potential applications in nonlinear metamaterials, tunable metamaterials and spintronics. (papers)

  4. Search for magnetic dipole strength and giant spin-flip resonances in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Horen, D. J. [Oak Ridge National Lab., TN (USA); Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    A description is given of the use of high resolution (n, n) scattering and the (p, n) reaction as tools to investigate highly excited states with emphasis on information pertaining to magnetic dipole strength and giant spin-flip resonances in heavy nuclei. It is shown how the ability to uniquely determine the spins and parities of resonances observed in neutron scattering has been instrumental to an understanding of the distribution of M1 strength in sup(207,208)Pb. Some recent results of (p, n) studies with intermediate energy protons are discussed. Energy systematics of the giant Gamow-Teller (GT) resonance as well as a new ..delta..l = 1, ..delta..S = 1 resonance with J sup(..pi..) = (1,2)/sup -/ are presented. It is shown how the (p, n) reaction might be useful to locate M1 strength in heavy nuclei.

  5. Giant cell tumor of the tendon sheath of the hand - magnetic resonance image and orthopaedic treatment

    International Nuclear Information System (INIS)

    Kirova, G.; Monovska, T.; Jablanski, V.; Alexieva, K.; Velev, M.

    2009-01-01

    Giant cell tumour of the tendon sheath (GCT-TS), also known as localized nodular tenosynovitis, is a benign neoplasm that occurs dominantly on the digits. These tumours most commonly occur in patients aged 30-50 years and are associated with degenerative joint disease. GCT-TS usually arises from the synovium of tendon sheets, affecting interfalangeal joints of the hand, feet, ankle and knees. Magnetic Resonance Imaging is able to depict characteristic signal intensities and can accurately assess the tumor size and degree of extent around the phalanx. We present a case of a 36 years-old male patient with GCT-TS in the flexor tendon of his left second finger, diagnosed with Magnetic Resonance imaging. The mass was excised widely with preservation of the flexor tendon without recurrence. (authors)

  6. Magnetic resonance imaging aspects of giant-cell tumours of bone

    International Nuclear Information System (INIS)

    Pereira, Helcio Mendoncça; Marchiori, Edson; Severo, Alessandro

    2014-01-01

    This study aimed to describe the magnetic resonance imaging (MRI) features of giant-cell tumours of bone. We analysed the clinical and MRI features of patients diagnosed with giant-cell tumours of bone confirmed by histopathology at our institution between 2010 and 2012. The peak incidence was between the second and third decades of life. There was no gender predominance. The most frequent locations were the knee and wrist. Pain and swelling were the prevailing symptoms. Fifty-one per cent of the patients were found to have associated secondary aneurysmal bone cysts on histopathology. On MRI, lesions demonstrated signal intensity equal to that of skeletal muscle on T1-weighted images and low signal intensity on T2-weighted images in 90% of cases. In gadolinium-enhanced T1-weighted images, 76.6% of cases demonstrated heterogeneous enhancement. We observed cystic components involving more than 50% of the lesion in 17 cases (56.6%). There was extra-osseous involvement in 13 cases (43.3%). MRI offers a valuable diagnostic tool for giant-cell tumours of bone. Contrast-enhanced MRI can distinguish between cystic and solid components of the tumour. MRI is also the imaging modality of choice for evaluation of soft-tissue involvement, offering a complete preoperative diagnosis.

  7. Sequential changes of magnetic resonance images of intracavernous giant aneurysm following carotid ligation

    International Nuclear Information System (INIS)

    Kinjo, Toshihiko; Mukawa, Jiro; Takara, Eiichi; Mekaru, Susumu; Ishikawa, Yasunari

    1986-01-01

    A case of intracavernous giant aneurysm treated by combined carotid ligation and extracranial-intracranial vein-graft bypass is reported with special reference to the sequential changes of Magnetic Resonance Images (MRI). A 29-year-old female was admitted to our clinic with complaint of diplopia. She had no neurological deficit except for left abducens palsy. Left carotid angiogram revealed an intracavernous giant aneurysm, and vertebral angiogram revealed a fenestration at right and an aneurysm-like buldging at left vertebral artery. Gradual carotid occlusion after extracranial-intracranial bypass via grafted saphnous vein was successfully performed without any neurological complications. Sequential changes of MRI were as follows: The aneurysm was shown by absent intensity both in spin echo (SE) and inversion recovery (IR) methods before the treatment. It became isointensity in SE and two-tone intensity, iso at the center and high at the margin, in IR 15 days after, and, furtheremore, became slight high intensity in SE but decreased in two-tone intensity, low at the center and high at the margin, in IR 37 days after complete carotid occlusion. Coronal view was usefull to understand anatomical relationship. In conclusion, MRI, especially coronal IR method is of more diagnostic value than X-ray CT to follow the thrombosis of intracavernous aneurysm. (author)

  8. Giant nuclear resonances

    International Nuclear Information System (INIS)

    Snover, K.A.

    1989-01-01

    Giant nuclear resonances are elementary mods of oscillation of the whole nucleus, closely related to the normal modes of oscillation of coupled mechanical systems. They occur systematically in most if not all nuclei, with oscillation energies typically in the range 10-30 MeV. One of the best - known examples is the giant electric dipole (El) resonance, in which all the protons and all the neutrons oscillate with opposite phase, producing a large time - varying electric dipole moment which acts as an effective antenna for radiating gamma ray. This paper discusses this mode as well as quadrupole and monopole modes

  9. Cardiac Sarcoidosis or Giant Cell Myocarditis? On Treatment Improvement of Fulminant Myocarditis as Demonstrated by Cardiovascular Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Hari Bogabathina

    2012-01-01

    Full Text Available Giant cell myocarditis, but not cardiac sarcoidosis, is known to cause fulminant myocarditis resulting in severe heart failure. However, giant cell myocarditis and cardiac sarcoidosis are pathologically similar, and attempts at pathological differentiation between the two remain difficult. We are presenting a case of fulminant myocarditis that has pathological features suggestive of cardiac sarcoidosis, but clinically mimicking giant cell myocarditis. This patient was treated with cyclosporine and prednisone and recovered well. This case we believe challenges our current understanding of these intertwined conditions. By obtaining a sense of severity of cardiac involvement via delayed hyperenhancement of cardiac magnetic resonance imaging, we were more inclined to treat this patient as giant cell myocarditis with cyclosporine. This resulted in excellent improvement of patient’s cardiac function as shown by delayed hyperenhancement images, early perfusion images, and SSFP videos.

  10. Isotopic effect giant resonances

    International Nuclear Information System (INIS)

    Buenerd, M.; Lebrun, D.; Martin, P.; Perrin, G.; Saintignon, P. de; Chauvin, J.; Duhamel, G.

    1981-10-01

    The systematics of the excitation energy of the giant dipole, monopole, and quadrupole resonances are shown to exhibit an isotopic effect. For a given element, the excitation energy of the transition decreases faster with the increasing neutron number than the empirical laws fitting the overall data. This effect is discussed in terms of the available models

  11. Isoscalar giant resonances

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, D. H. [Texas A and M Univ., College Station (USA). Cyclotron Inst.; Ikegami, H.; Muraoka, M. [eds.

    1980-01-01

    The current status of the knowledges of giant quadrupole resonance (GQR), low energy octupole resonance (LEOR), and giant monopole resonance (GMR), is described. In the lowest order of multipole resonance, both isoscalar and isovector modes can occur. The characteristics of the GQR in light nuclei are apparent in the experimental result for Mg-24. All of the isoscalar E2 strength are known in Mg-24. The Goldhaber-Teller model is preferred over the Steinwedel-Jensen model for the giant dipole resonance (GDR) transition density. A few interesting and puzzling features have been seen in Pb-208. There is some conflict between inelastic alpha and electron scatterings. About LEOR, the RPA calculation of Liu and Brown was compared to the data for 3/sup -/ strength in Ca-40, Zr-90 and Pb-208. The calculation was employed the residual interaction of the Skyrme type. The agreement in Zr-90 was excellent. The effect of quadrupole deformation on the LEOR in Sm isotopes was large. The inelastic alpha scattering data on Al-27, Ca-40, Ti-48, Ni-58, Zn-64 and 66, Zr-90, Sn-116, 118, 120 and 124, Sm-144, 148 and 154, and Pb-208 were utilized in order to identify the GMR, and the GMR parameters were obtained. The GMR exhausting a large fraction of the sum rule was apparent in the nuclei with mass larger than 90. The splitting of the GDR and the broadening of the GQR in permanently deformed nuclei were established. The splitting of GMR was seen in Sm-154. The studies with heavy ions are also described.

  12. Hadron excitation of giant resonances

    International Nuclear Information System (INIS)

    Morsch, H.-P.

    1985-01-01

    A review is given on giant resonance studies in heavy nuclei using scattering of different hadronic probes. Concerning isoscalar giant resonances compression modes are discussed with the possibility to obtain more detailed structure information. From detailed studies of α scattering the distribution of isoscalar strengths of multipolarity up to L=6 was obtained. Some recent aspects of heavy ion excitation of collective modes are mentioned. The possibility to study isovector giant resonances in hadron charge exchange reactions is discussed. Finally, a comparison is made between α and 200 MeV proton scattering from which isoscalar and spin-isospin continuum response are extracted. (orig.)

  13. Statistical decay of giant resonances

    International Nuclear Information System (INIS)

    Dias, H.; Teruya, N.; Wolynec, E.

    1986-01-01

    Statistical calculations to predict the neutron spectrum resulting from the decay of Giant Resonances are discussed. The dependence of the resutls on the optical potential parametrization and on the level density of the residual nucleus is assessed. A Hauser-Feshbach calculation is performed for the decay of the monople giant resonance in 208 Pb using the experimental levels of 207 Pb from a recent compilation. The calculated statistical decay is in excelent agreement with recent experimental data, showing that the decay of this resonance is dominantly statistical, as predicted by continuum RPA calculations. (Author) [pt

  14. Statistical decay of giant resonances

    International Nuclear Information System (INIS)

    Dias, H.; Teruya, N.; Wolynec, E.

    1986-02-01

    Statistical calculations to predict the neutron spectrum resulting from the decay of Giant Resonances are discussed. The dependence of the results on the optical potential parametrization and on the level density of the residual nucleus is assessed. A Hauser-Feshbach calculation is performed for the decay of the monopole giant resonance in 208 Pb using the experimental levels of 207 Pb from a recent compilation. The calculated statistical decay is in excellent agreement with recent experimental data, showing that decay of this resonance is dominantly statistical, as predicted by continuum RPA calculations. (Author) [pt

  15. Giant intracranial aneurysms; Magnetic resonance imaging follow-up and clinical symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Kondoh, Takeshi; Fujita, Katsuzo; Tamaki, Norihiko; Matsumoto, Satoshi [Kobe Univ. (Japan). School of Medicine; Yamashita, Haruo; Shirakata, Masaya

    1991-06-01

    Twenty-four intracranial aneurysms over 20 mm in diameter were studied with magnetic resonance (MR) imaging. MR imaging follow-up of eight cases revealed induced thrombus with homogeneous intensity and decreased size even after complete intraluminal thrombosis. Most cases demonstrated homogeneous intensity thrombus in contrast to the heterogeneous intensity of spontaneous thrombus. The clinical symptoms could not be explained retrospectively by the thrombus characteristics. Perianeurysmal high intensity, indicating cerebral edema, was detected in one case presenting with a rapid increase in size. MR imaging is useful for following these pathological intra- and perianeurysmal changes. (author).

  16. Giant first-forbidden resonances

    International Nuclear Information System (INIS)

    Krmpotic, F.; Nakayama, K.; Sao Paulo Univ.; Pio Galeao, A.; Sao Paulo Univ.

    1983-01-01

    Recent experimental data on first-forbidden charge-exchange resonances are discussed in the framework of a schematic model. We also evaluate the screening of the weak coupling constants induced by both the giant resonances and the δ-isobar. It is shown that the last effect does not depend on the multipolarity of the one-particle moment. Due to the same reason, the fraction of the reaction strength pushed up into the δ-resonance region is always the same regardless of the quantum numbers carried by the excitation. Simple expressions are derived for the dependence of the excitation energies of the first-forbidden giant resonances on the mass number and isospin of the target. The model reproduces consistently both the Gamow-Teller and the first-forbidden resonances. (orig.)

  17. Giant resonances: reaction theory approach

    International Nuclear Information System (INIS)

    Toledo Piza, A.F.R. de; Foglia, G.A.

    1989-09-01

    The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenomena as complicated dynamical syndromes so that theoretical requirements for their study must be extended beyond the traditional bounds of nuclear structure models. The spectra of decay products following GMR excitation in heavy nuclei are well described by statistical model (Hauser-Feshback, HF) predictions indicated that spreading of the collective modes plays a major role in shaping exclusive cross-sections. (A.C.A.S.) [pt

  18. Excitation of giant resonances in heavy ion collisions

    International Nuclear Information System (INIS)

    Kuehn, W.

    1991-01-01

    Introduction: What are Giant Resonances? General Features of Giant Resonances, Macroscopic Description and Classification, Basic Excitation Mechanisms, Decay Modes, Giant Resonances Built on Excited States, Relativistic Coulomb Excitation of Giant Resonances, Experimental Situation. (orig.)

  19. Giant Vertebral Notochordal Rest: Magnetic Resonance and Diffusion Weighted Imaging Findings

    International Nuclear Information System (INIS)

    Oner, Ali Yusuf; Akpek, Sergin; Tali, Turgut; Ucar, Murat

    2009-01-01

    A giant vertebral notochordal rest is a newly described, benign entity that is easily confused with a vertebral chordoma. As microscopic notochordal rests are rarely found in adult autopsies, the finding of a macroscopic vertebral lesion is a new entity with only seven previously presented cases. We report here radiological findings, including diffusion weighted images, of a patient with a giant notochordal remnant confined to the L5 vertebra, with an emphasis on its distinction from a chordoma

  20. Giant multipole resonances: perspectives after ten years

    International Nuclear Information System (INIS)

    Bertrand, F.E.

    1980-01-01

    Nearly ten years ago evidence was published for the first of the so-called giant multipole resonances, the giant quadrupole resonance. During the ensuing years research in this field has spread to many nuclear physics laboratories throughout the world. The present status of electric giant multipole resonances is reviewed. 24 figures, 1 table

  1. Giant resonances on excited states

    International Nuclear Information System (INIS)

    Besold, W.; Reinhard, P.G.; Toepffer, C.

    1984-01-01

    We derive modified RPA equations for small vibrations about excited states. The temperature dependence of collective excitations is examined. The formalism is applied to the ground state and the first excited state of 90 Zr in order to confirm a hypothesis which states that not only the ground state but every excited state of a nucleus has a giant resonance built upon it. (orig.)

  2. Study of giant resonances in heavy nuclei

    International Nuclear Information System (INIS)

    Cataldi, M.I.C.

    1986-01-01

    The electrodisintegration cross section for 181 Ta, 208 Pb and 209 Bi was measured by counting the emitted neutrons, with incident electrons in the energy range 8-22 MeV. The data was analysed using the virtual photon method, in order to obtain a multipole decomposition and the intensities of Magnetic Dipole and Electric Quadrupole, isoscalar and isovector, in the Giant Resonance. The results obtained for the isovector Giant Quadrupole Resonance are compared with the measured photodisintegration cross section, using data from Saclay and Livermore. This comparision indicates that the photodisintegration data can be well explained assuming an isovector E2 Resonance located between 120 and 130 A -1/3 MeV, with an intensity of one isovector E2 sum. (author) [pt

  3. Determination of giant resonance strengths

    International Nuclear Information System (INIS)

    Serr, F.E.

    1983-01-01

    Using theoretical strength functions to describe the different giant resonances expected at excitation energies of the order of (60-85)/Asup(1/3) MeV, we calculate the double differential cross sections d 2 sigma/dΩ dE associated with the reactions 208 Pb(α, α') and 90 Zr(α, α') (Esub(α) = 152 MeV). The angular distributions for the giant quadrupole and giant monopole resonances obtained from fits to these spectra, making simple, commonly used assumptions for the peak shapes and background, are compared to the original angular distributions. The differences between them are an indication of some of the uncertainties affecting the giant resonance strengths extracted from hadron inelastic scattering data. Fits to limited angular regions lead to errors of up to 50% in the value of the energy-weighted sum rule, depending on the angles examined. While it seems possible to extract the correct EWSR for the GMR by carrying out the analyses at 0 0 , no single privileged angle seems to exist in the case of the GQR. (orig.)

  4. Solid state deuterium nuclear magnetic resonance detection of transmembrane-potential-driven tetraphenylphosphonium redistribution across Giant Unilamellar Vesicle bilayers

    International Nuclear Information System (INIS)

    Franzin, Carla Maria Mirella

    1995-01-01

    It has been demonstrated that deuterium nuclear magnetic resonance ( 2 H NMR) of Giant Unilamellar Vesicles (GUVs) consisting of specifically choline-deuterated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), plus 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) and cholesterol can be used to monitor the transbilayer redistribution of tetraphenylphosphonium (TPP + ) in response to a transmembrane potential (δψ tm ). The 2 H quadrupolar splittings (δν Q 's) measured reflect the level of TPP + bound at the membrane surface due to the latter's effect on the membrane surface electrostatic potential, ψ s . Results reveal the appearance of two distinct δν Q 's, due to differences in bound TPP + at the inner versus the outer monolayer in response to a δψ tm . The observed values of the δν Q 's agree with theoretical predictions based on a derived mathematical model that takes into account δψ tm , plus ψ s , plus the equilibrium binding of TPP + from solution onto the membrane surface, plus the sensitivity of δν Q to the amount of bound TPP + . This model identifies experimental factors that lead to improvements in spectral resolution. Henceforth, 2 H NMR is a valuable tool for quantifying transmembrane asymmetries of ψ s . (author)

  5. On Landau Vlasov simulations of giant resonances

    International Nuclear Information System (INIS)

    Pi, M.; Schuck, P.; Suraud, E.; Gregoire, C.; Remaud, B.; Sebille, F.

    1987-05-01

    We present VUU calculations of giant resonances obtained in energetic heavy ion collisions. Also is considered the case of the giant dipole in 40 Ca and the possibility of studying the effects of rotation on such collective modes

  6. Giant multipole resonances: an experimental review

    International Nuclear Information System (INIS)

    Bertrand, F.E.

    1979-01-01

    During the past several years experimental evidence has been published for the existance of nondipole giant resonances. These giant multipole resonances, the so-called new giant resonances were first observed through inelastic hadron and electron scattering and such measurements have continued to provide most of the information in this field. A summary is provided of the experimental evidence for these new resonances. The discussion deals only with results from inelastic scattering and only with the electric multipoles. Emphasis is placed on the recent observations of the giant monopole resonance. Results from recent heavy-ion and pion inelastic scattering are discussed. 38 references

  7. Giant resonances in heavy-ion reactions

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1982-11-01

    The several roles of multipole giant resonances in heavy-ion reactions are discussed. In particular, the modifications in the effective ion-ion potencial due to the virtual excitation of giant resonances at low energies, are considered and estimated for several systems. Real excitation of giant resonances in heavy-ion reactions at intermediate energies are then discussed and their importance in the approach phase of deeply inelastic processes in emphasized. Several demonstrative examples are given. (Author) [pt

  8. Giant dipole resonance in hot nuclei

    International Nuclear Information System (INIS)

    Mau, N.V.

    1993-01-01

    Giant resonances built on an excited state of the nucleus at a finite temperature T are studied. The following questions are investigated: how long such collective effects occur in a nucleus when T increases. How the properties of the giant resonances vary when the temperature increases. How the study of giant resonances in hot nuclei can give information on the structure of the nucleus in a highly excited state. The special case of the giant dipole resonance is studied. Some of the experimental results are reviewed and in their theoretical interpretation is discussed. (K.A.). 56 refs., 20 figs., 4 tabs

  9. Electromagnetic decay of giant resonances

    International Nuclear Information System (INIS)

    Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Auble, R.L.; Hensley, D.C.; Horen, D.J.; Robinson, R.L.; Sayer, R.O.; Sjoreen, T.P.

    1985-01-01

    Coincidence experiments were done to investigate the photon and neutron emission from the giant resonance regions of 208 Pb and 90 Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in 208 Pb to approx.15 MeV. Similar data were also obtained on 90 Zr. The total yield of ground-state E2 gamma radiation in 208 Pb and the comparative absence of such radiation in 90 Zr can only be understood if decay of compound (damped) states is considered. Other observations in 208 Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the 3 - state at 2.6 MeV, a strong branch to a 3 - state at 4.97 MeV from the same region, and transitions to various 1 - states between 5 to 7 MeV from the E* approx. 14 MeV region (EO resonance)

  10. Magnetic resonance annual 1986

    International Nuclear Information System (INIS)

    Kressel, H.Y.

    1986-01-01

    This book contains papers written on magnetic resonance during 1986. Topics include: musculosketetal magnetic resonance imaging; imaging of the spine; magnetic resonance chemical shift imaging; magnetic resonance imaging in the central nervous system; comparison to computed tomography; high resolution magnetic resonance imaging using surface coils; magnetic resonance imaging of the chest; magnetic resonance imaging of the breast; magnetic resonance imaging of the liver; magnetic resonance spectroscopy of neoplasms; blood flow effects in magnetic resonance imaging; and current and potential applications of clinical sodium magnetic resonance imaging

  11. Excitation of giant monopole and quadrupole resonances

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, H. [Osaka Univ., Suita (Japan). Research Center for Nuclear Physics; Yamagata, T.; Tanaka, M. [and others; Ikegami, H.; Muraoka, M. [eds.; Osaka Univ., Suita (Japan). Research Center for Nuclear Physics

    1980-01-01

    Recent studies on the giant monopole resonance (GMR) and the giant quadrupole resonance (GQR) in /sup 144/Sm and /sup 208/Pb using the ..cap alpha..-scattering performed at RCNP are summarized. The observed angular range covered 1.6/sup 0/ -- 7/sup 0/ with a coupled system of a dipole and a triplet quadrupole magnet. The incident energy was changed from 84 to 119 MeV. The resonance shapes and energy-weighted sum-rule strengths of the GMR and the GQR were reliably deduced as a function of incident energy. The quadrupole strength of --20% was found in the GMR region. The observed excitation function of the GMR was compared with the DWBA calculation, in which the Satchler's Version I was used as a form factor representing the compressional motion of the nucleus. It was found that the experimental excitation function of the GMR shows steeper decrease as lowering the incident energy than the DWBA prediction whereas that of the GQR is successfully described by the DWBA. This suggests that examination of the model describing the GMR is necessary.

  12. Electromagnetic decay of giant resonances

    International Nuclear Information System (INIS)

    Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Auble, R.L.; Hensley, D.C.; Horen, D.J.; Robinson, R.L.; Sayer, R.O.; Sjoreen, T.P.

    1985-01-01

    Coincidence experiments are carried out to investigate the photon and neutron emission from the giant resonance regions of 208 Pb and 90 Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. The authors determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in 208 Pb to ∼15 MeV. Similar data were also obtained on 90 Zr. The total yield of ground-state E2 gamma radiation in 208 Pb and the comparative absence of such radiation in 90 Zr can only be understood if decay of compound (damped) states is considered. (Auth.)

  13. Multipole giant resonances in highly excited nuclei

    International Nuclear Information System (INIS)

    Xia Keding; Cai Yanhuang

    1989-01-01

    The isoscalar giant surface resonance and giant dipole resonance in highly excited nuclei are discussed. Excitation energies of the giant modes in 208 Pb are calculated in a simplified model, using the concept of energy wieghted sum rule (EWSR), and the extended Thomas-Fermi approximation at the finite temperature is employed to describe the finite temperature is employed to describe the finite temperature equilibrium state. It is shown that EWSR and the energy of the resonance depend only weakly on temperature in the system. This weak dependence is analysed

  14. Static electromagnetic properties of giant resonances

    International Nuclear Information System (INIS)

    Koo, W.K.

    1986-03-01

    Static electric monopole and quadrupole matrix elements, which are related to the mean square radius and quadrupole moment respectively, are derived for giant resonances of arbitrary multipolarity. The results furnish information on the size and shape of the nucleus in the excited giant states. (author)

  15. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

  16. Looking inside giant resonance fine structure

    International Nuclear Information System (INIS)

    Ponomarev, V.Yu.; Voronov, V.V.

    1993-01-01

    Microscopic calculations of the fine structure of giant resonances for spherical nuclei are presented. Excited states are treated by wave function which takes into account coupling of simple one-phonon configurations with more complex ones. Nuclear structure calculations are applied to the description of the γ-decay of resonances into the ground and low-lying excited states. 16 refs.; 4 figs

  17. Excitation of giant resonances through inelastic scattering

    International Nuclear Information System (INIS)

    Kailas, S.

    1981-01-01

    In the last few years, exciting developments have taken place in the study of giant resonances (GR). In addition to the already well known gjant dipole resonance (GDR), the presence of at least two more new GRs viz. giant quadrupole resonance (GQR) and giant monopole resonance (GMR) has been experimentally established. The systematics covering these GRs is found to be consistent with the theoretical expectation. Though the existence of higher multipoles has been predjcted by theory, so far only some of these have been found to be excited experimentally. Various probe particles - electrons, protons (polarized and unpolarized), light and heavy ions and pions - at different bombarding energies have been used to excite the GR region, primarily through the inelastic scattering process. Detailed experiments, looking at the decay modes of GR region, have also been performed. These studies have contributed significantly to a better understanding of the phenomenon of nuclear collective excitation. In this report, the current status of 'GR' research is reviewed. (author)

  18. Collective motion and giant resonances

    International Nuclear Information System (INIS)

    Wilhelmi, Z.; Kicinska-Habior, M.

    1984-01-01

    The report contains 15 papers devoted to problems of giant collective excitations of nuclei, heavy-ion induced reactions and their bearing on various aspects of nuclear structure. In some of them the numerical data are given. (A.S.)

  19. Giant Primeval Magnetic Dipoles

    Science.gov (United States)

    Thompson, Christopher

    2017-07-01

    Macroscopic magnetic dipoles are considered cosmic dark matter. Permanent magnetism in relativistic field structures can involve some form of superconductivity, one example being current-carrying string loops (“springs”) with vanishing net tension. We derive the cross-section for free classical dipoles to collide, finding it depends weakly on orientation when mutual precession is rapid. The collision rate of “spring” loops with tension { T }˜ {10}-8{c}4/G in galactic halos approaches the measured rate of fast radio bursts (FRBs) if the loops compose most of the dark matter. A large superconducting dipole (LSD) with mass ˜1020 g and size ˜1 mm will form a ˜100 km magnetosphere moving through interstellar plasma. Although hydromagnetic drag is generally weak, it is strong enough to capture some LSDs into long-lived rings orbiting supermassive black holes (SMBHs) that form by the direct collapse of massive gas clouds. Repeated collisions near young SMBHs could dominate the global collision rate, thereby broadening the dipole mass spectrum. Colliding LSDs produce tiny, hot electromagnetic explosions. The accompanying paper shows that these explosions couple effectively to propagating low-frequency electromagnetic modes, with output peaking at 0.01-1 THz. We describe several constraints on, and predictions of, LSDs as cosmic dark matter. The shock formed by an infalling LSD triggers self-sustained thermonuclear burning in a C/O (ONeMg) white dwarf (WD) of mass ≳1 M ⊙ (1.3 M ⊙). The spark is generally located off the center of the WD. The rate of LSD-induced explosions matches the observed rate of Type Ia supernovae.

  20. Isovector giant quadrupole resonance in 63Cu

    International Nuclear Information System (INIS)

    Wolynec, E.; Pastura, V.F.S.; Martins, M.N.

    1988-01-01

    The decay of the isovector E2 giant resonance in 63 Cu has been studied by measuring the (e,2n) cross section, in the incident electron energy range 22-45 MeV. The photodisintegration induced by bremsstrahlung was also measured. The electrodisintegration results have been analyzed using the distorted wave Born approximation E1 and E2 virtual photon spectra to obtain these multipole components in the corresponding (γ,2n) cross section. It is found that the isovector E2 giant resonance decays dominantly by two-neutron emission in 63 Cu. This decay channel exhausts 65 percent of the energy weighted E2 sum. (author0 [pt

  1. Macroscopic description of isoscalar giant multipole resonances

    International Nuclear Information System (INIS)

    Nix, J.R.; Sierk, A.J.

    1980-01-01

    On the basis of a simple macroscopic model, we calculate the isoscalar giant-resonance energy as a function of mass number and multipole degree. The restoring force is determined from the distortion of the Fermi surface, and the inertia is determined for the incompressible, irrotational flow of nucleons with unit effective mass. With no adjustable parameters, the resulting closed expression reproduces correctly the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole energy and the magnitude of the giant octupole energy for 208 Pb. We also calculate the isoscalar giant-resonance width as a function of mass number and multipole degree for various macroscopic damping mechanisms, including two-body viscosity, one-body dissipation, and modified one-body dissipation. None of these damping mechanisms reproduces correctly all features of the available experimental data, namely the magnitude and dependence upon mass number of the giant quadrupole width and the magnitude of the giant octupole width for 208 Pb

  2. Study of giant resonances with pions

    International Nuclear Information System (INIS)

    Baer, H.W.

    1984-01-01

    Recent results on giant resonances obtained with pion-inelastic scattering and with single- and double-charge-exchange scattering are reviewed. The states discussed are isobaric analog states, double-isobaric analog states, and isovector L = 0, 1, and 2 collective states. 36 references

  3. Giant resonances in the deformed continuum

    International Nuclear Information System (INIS)

    Nakatsukasa, T.; Yabana, K.

    2004-01-01

    Giant resonances in the continuum for deformed nuclei are studied with the time-dependent Hartree-Fock (TDHF) theory in real time and real space. The continuum effect is effectively taken into account by introducing a complex Absorbing Boundary Condition (ABC). (orig.)

  4. Giant dipole resonances built on excited states

    International Nuclear Information System (INIS)

    Snover, K.A.

    1983-01-01

    The properties of giant dipole resonances built on excited nuclear states are reviewed, with emphasis on recent results. Nonstatistical (p,γ) reactions in light nuclei, and statistical complex-particle reactions in light and heavy nuclei are discussed. 27 references

  5. Giant dipole resonance by many levels theory

    International Nuclear Information System (INIS)

    Mondaini, R.P.

    1977-01-01

    The many levels theory is applied to photonuclear effect, in particular, in giant dipole resonance. A review about photonuclear dipole absorption, comparing with atomic case is done. The derivation of sum rules; their modifications by introduction of the concepts of effective charges and mass and the Siegert theorem. The experimental distributions are compared with results obtained by curve adjustment. (M.C.K.) [pt

  6. Stability of the giant dipole resonance

    International Nuclear Information System (INIS)

    Espino, J.M.; Gallardo, M.

    1987-01-01

    The Giant Dipole Resonance (GDR), because of its stability and its typical period of vibration, can be used as a test for compound nucleus reactions at high temperatures. This stability is studied in a simple model up to 6 MeV of temperature. The experimental methods for getting the properties of the GDR at T ≠ 0 are also commented. (author)

  7. Electroexcitation of giant resonances in 181Ta

    International Nuclear Information System (INIS)

    Hicks, R.S.; Auer, I.P.; Bergstrom, J.C.; Caplan, H.S.

    1977-01-01

    The giant resonance region of 181 Ta has been investigated by means of inelastic electron scattering with primary electron energies of 79.1 to 118.3 MeV. A peak-fitting procedure was employed to separate the measured spectrum into nine different resonance components. Multipolarity and strength assignments were deduced using DWBA analysis with the Goldhaber-Teller and Steinwedel-Jensen models. In addition to the well-known giant dipole structure, other resonances were identified at 23.2+-0.3 MeV (E2), 9.5+-0.2 and 11.5+-0.2 MeV (E2 or E0), 19.5+-0.8 MeV (E3), 3.70+-0.14 MeV (E3 or E4), and 5.40+-0.15 MeV (E4 or E5). The model dependence of the analysis is discussed. (Auth.)

  8. Pediatric magnetic resonance imaging

    International Nuclear Information System (INIS)

    Cohen, M.D.

    1986-01-01

    This book defines the current clinical potential of magnetic resonance imaging and focuses on direct clinical work with pediatric patients. A section dealing with the physics of magnetic resonance imaging provides an introduction to enable clinicians to utilize the machine and interpret the images. Magnetic resonance imaging is presented as an appropriate imaging modality for pediatric patients utilizing no radiation

  9. Photon scattering by the giant dipole resonance

    International Nuclear Information System (INIS)

    Bowles, T.J.; Holt, R.J.; Jackson, H.E.; McKeown, R.D.; Specht, J.R.

    1979-01-01

    Although many features of the giant dipole resonance are well known, the coupling between the basic dipole oscillation and other nuclear collective degrees of freedom such as surface vibrations and rotations is poorly understood. This aspect was investigated by elastic and inelastic bremsstrahlung scattering of tagged photons over the energy range 15 to 22 MeV. Target nuclei were 60 Ni, 52 Cr, 56 Fe, 92 Mo, and 96 Mo. Scattering and absorption cross sections are tabulated, along with parameters obtained from a two-Lorentzian analysis of the scattering cross sections; measured spectra are shown. It was necessary to remove Thomson scattering from the experimental results. It was found that coupling to surface vibrations in the giant dipole resonance is much weaker than the dynamic collective model suggests. The elastic scattering cross section for all targets but 60 Ni showed structure that is not evident in the absorption cross section measurement. 12 figures, 2 tables

  10. Triple Giant Resonance Excitations: A Microscopic Approach

    International Nuclear Information System (INIS)

    Lanza, E.G.; Andres, M.V.; Catara, F.; Chomaz, Ph.; Fallot, M.; Scarpaci, J.A.

    2007-01-01

    We present, for the first time, microscopic calculations of inelastic cross sections of the triple excitation of giant resonances induced by heavy ion probes. We start from a microscopic approach based on RPA. The mixing of three-phonon states among themselves and with two- and one-phonon states is considered within a boson expansion with Pauli corrections. In this way we go beyond the standard harmonic approximations and get anharmonic excitation spectra. At the same time we also introduce non-linearities in the external field. The calculations are done by solving semiclassical coupled channel equations, the channels being superpositions of one-, two- and three-phonon states. Previous calculations for the Double Giant Resonance excitation show good agreement with experimental cross sections. The inclusion of the three phonon components confirms the previous results for the DGR and produces a strong increase in the Triple GR energy region

  11. Giant resonance effects in radiative capture

    International Nuclear Information System (INIS)

    Snover, K.A.

    1979-01-01

    The technique of capture reaction studies of giant resonance properties is described, and a number of examples are given. Most of the recent work of interest has been in proton capture, in part because of the great utility (and availability) of polarized beams; most of the discussion concerns this reaction. Alpha capture, which has been a useful tool for exploring isoscalar E2 strength, and neutron capture are, however, also treated. 46 references, 14 figures

  12. Isotopic dependence of giant multipole resonances

    International Nuclear Information System (INIS)

    Bar Touv, J.; Moalem, A.; Shlomo, S.

    1980-01-01

    A procedure is presented which allows the application of linear response theory and the random phase approximation to an open shell. The procedure is applied to Ca isotopes. The general features of giant multipole resonances are found to vary smoothly with the mass. The resonances exhibit more structure in the open lfsub(7/2) shell nuclei. While the energy-weighted dipole sum is practically constant in all isotopes, the isoscalar quadrupole and octupole energy weighted sums increase continuously by approx. 30% from 40 Ca to 48 Ca. (orig.)

  13. High temperature giant dipole and isoscalar resonances

    International Nuclear Information System (INIS)

    Navarro, J.; Barranco, M.; Garcias, F.; Suraud, E.

    1990-01-01

    We present a systematic study of the Giant Dipole Resonance (GDR) at high temperatures (T > ∼ 4 MeV) in the framework of a semi-classical approximation that uses the m 1 and m 3 RPA sum rules to estimate the GDR mean energy. We focus on the evolution with T of the collective nature of the GDR and of the L = 0,2,3 and 4 isoscalar resonances. We find that the GDR remains particularly collective at high T, suggesting that it might be possible to observe it experimentally even at temperatures close to the maximum one a nucleus can sustain

  14. Large Mn25 single-molecule magnet with spin S = 51/2: magnetic and high-frequency electron paramagnetic resonance spectroscopic characterization of a giant spin state.

    Science.gov (United States)

    Murugesu, Muralee; Takahashi, Susumu; Wilson, Anthony; Abboud, Khalil A; Wernsdorfer, Wolfgang; Hill, Stephen; Christou, George

    2008-10-20

    The synthesis and structural, spectroscopic, and magnetic characterization of a Mn25 coordination cluster with a large ground-state spin of S = 51/2 are reported. Reaction of MnCl2 with pyridine-2,6-dimethanol (pdmH2) and NaN3 in MeCN/MeOH gives the mixed valence cluster [Mn25O18(OH)2(N3)12(pdm)6(pdmH)6]Cl2 (1; 6Mn(II), 18Mn(III), Mn(IV)), which has a barrel-like cage structure. Variable temperature direct current (dc) magnetic susceptibility data were collected in the 1.8-300 K temperature range in a 0.1 T field. Variable-temperature and -field magnetization (M) data were collected in the 1.8-4.0 K and 0.1-7 T ranges and fit by matrix diagonalization assuming only the ground state is occupied at these temperatures. The fit parameters were S = 51/2, D = -0.020(2) cm(-1), and g = 1.87(3), where D is the axial zero-field splitting parameter. Alternating current (ac) susceptibility measurements in the 1.8-8.0 K range and a 3.5 G ac field oscillating at frequencies in the 50-1500 Hz range revealed a frequency-dependent out-of-phase (chi(M)'') signal below 3 K, suggesting 1 to be a single-molecule magnet (SMM). This was confirmed by magnetization vs dc field sweeps, which exhibited hysteresis loops but with no clear steps characteristic of resonant quantum tunneling of magnetization (QTM). However, magnetization decay data below 1 K were collected and used to construct an Arrhenius plot, and the fit of the thermally activated region above approximately 0.5 K gave U(eff)/k = 12 K, where U(eff) is the effective relaxation barrier. The g value and the magnitude and sign of the D value were independently confirmed by detailed high-frequency electron paramagnetic resonance (HFEPR) spectroscopy on polycrystalline samples. The combined studies confirm both the high ground-state spin S = 51/2 of complex 1 and that it is a SMM that, in addition, exhibits QTM.

  15. Magnetic resonance imaging apparatus

    International Nuclear Information System (INIS)

    Ehnholm, G.J.

    1991-01-01

    This patent describes an electron spin resonance enhanced magnetic resonance (MR) imaging (ESREMRI) apparatus able to generate a primary magnetic field during periods of nuclear spin transition excitation and magnetic resonance signal detection. This allows the generation of ESREMRI images of a subject. A primary magnetic field of a second and higher value generated during periods of nuclear spin transition excitation and magnetic resonance signal detection can be used to generate conventional MR images of a subject. The ESREMRI and native MR images so generated may be combined, (or superimposed). (author)

  16. Actual problems of giant resonance physics

    International Nuclear Information System (INIS)

    Zhalov, M.B.; Sliv, L.A.

    1982-01-01

    The raper deals with the discussion of theoretical problems associated with investigation into nuclear giant multipole resoonances (GMR). Analysis of test data on inelastic scattering of particles on nuclei is carried out to obtain the main GMR characteristics from the present experimental data. Giant isoscalar resonances and their structures in the random phase approximatmion (RPA) with Skyrm forces described by the microscopic theory are discussed. Cross section of 40 Ca excitation in reaction of α-particle inelastic scattering calculated in RPA with exact accountancy of one-nucleon continuum is graphically displayed as an example. Modified RPA used for calculation of GMR width is suggested. Conducted is comparison of energies of 40 Ca, 58 Ni, 90 Zr, 208 Pb nuclei isoscalar resonances calculated in RPA and their contributions to energy weighted sum rule the results of which are tabulated. Integral strength of resonance excitation in RPA by inelastic-scattered α particles and protons on 40 Ca and 208 Pb nuclei is considered. Channels of GMR disintegration are discussed. The most significant theoretical and experimental problems the solution of which is necessary for complete investigation of GMR are pointed out

  17. Monopole Giant Resonances and TDHF boundary conditions

    International Nuclear Information System (INIS)

    Stevenson, P.D.; Almehed, D.; Reinhard, P.-G.; Maruhn, J.A.

    2007-01-01

    Using time-dependent Hartree-Fock, we induce isoscalar and isovector monopole vibrations and follow the subsequent vibrations of both the same and opposite isospin nature in the N Z nucleus 132 Sn. By suitable scaling of the proton and neutron parts of the excitation operators, the coupling between the modes is studied, and the approximate normal modes found. Chaotic dynamics are then analysed in the isoscalar giant monopole resonance by using reflecting boundaries in a large space to build up a large number of 0 + states whose spacings are then analysed. A Wigner-like distribution is found

  18. Temperature dependence of giant dipole resonance width

    International Nuclear Information System (INIS)

    Vdovin, A.I.; Storozhenko, A.N.

    2005-01-01

    The quasiparticle-phonon nuclear model extended to finite temperature within the framework of the thermo field dynamics is applied to calculate a temperature dependence of the spreading width Γ d own of a giant dipole resonance. Numerical calculations are made for 12S n and 208 Pb nuclei. It is found that the width Γ d own increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones existing in the literature

  19. Collective Hamiltonians for dipole giant resonances

    International Nuclear Information System (INIS)

    Weiss, L.I.

    1991-07-01

    The collective hamiltonian for the Giant Dipole resonance (GDR), in the Goldhaber-Teller-Model, is analytically constructed using the semiclassical and generator coordinates method. Initially a conveniently parametrized set of many body wave functions and a microscopic hamiltonian, the Skyrme hamiltonian - are used. These collective Hamiltonians are applied to the investigation of the GDR, in He 4 , O 16 and Ca 40 nuclei. Also the energies and spectra of the GDR are obtained in these nuclei. The two sets of results are compared, and the zero point energy effects analysed. (author)

  20. Isoscalar giant resonances in a relativistic model

    International Nuclear Information System (INIS)

    L'Huillier, M.; Nguyen Van Giai.

    1988-07-01

    Isoscalar giant resonances in finite nuclei are studied in a relativistic Random Phase Approximation (RRPA) approach. The model is self-consistent in the sense that one set of coupling constants generates the Dirac-Hartree single-particle spectrum and the residual particle-hole interaction. The RRPA is used to calculate response functions of multipolarity L = 0,2,3, and 4 in light and medium nuclei. It is found that monopole and quadrupole modes exhibit a collective character. The peak energies are overestimated, but not as much as one might think if the bulk properties (compression modulus, effective mass) were the only relevant quantities

  1. Evidence for deformation effect on the giant monopole resonance

    International Nuclear Information System (INIS)

    Buenerd, M.; Lebrun, D.; Martin, P.; de Saintignon, P.; Perrin, C.

    1980-01-01

    The giant monopole resonance in the region of deformed nuclei has been investigated by inelastic scattering of 108.5 MeV 3 He at very small scattering angles. Evidence is reported for coupling between the giant monopole and giant quadrupole vibrations, based both on energy shift and transition strength

  2. The sympletic model for giant monopole resonances

    International Nuclear Information System (INIS)

    Oliveira, M.M.B.M.

    1985-01-01

    Following recently published articles, it's investigated how to apply the sympletic model to the study of giant monopole resonances in spherical nuclei. The results obtained agree with those already published for monopole mode energies, wave functions, radii and nuclear incompressibility of 16 O and 40 Ca nuclei. An analyse of how the spurious center-of-mass motion influence resonance energies is made. The sum rules of the monopole operator, m-bar e , o ≤ e ≤ 3, are calculated, demonstrating at first that they are conserved in the sympletic model. Then it's studied, for those sum rules, the importance of n-boson correlations in the fundamental state, which is an extension of those sum rules, of the analysis for the nuclear incompressibility, performed in above mentioned articles. (Author) [pt

  3. Giant resonances in hot rotating nuclei

    International Nuclear Information System (INIS)

    Ring, P.

    1992-01-01

    Present theoretical descriptions of the giant resonances in hot rotating nuclei are reviewed. Mean field theory is used as a basis for the description of the hot compound states. Starting from the static solution at finite temperature and with fixed angular momentum small amplitude collective vibrations are calculated in the frame work of finite temperature random phase approximation for quasi-particles. The effect of pairing at low temperatures as well as the effect of rotations on the position of the resonance maxima are investigated. Microscopic and phenomenological descriptions of the damping mechanisms are reviewed. In particular it turns out that fluctuations play an important role in understanding of the behaviour of the width as a function of the temperature. Motional narrowing is critically discussed. (author). 99 refs., 5 figs

  4. Condensed matter view of giant resonance phenomena

    International Nuclear Information System (INIS)

    Zangwill, A.

    1987-01-01

    The intent of this article is to present a view of giant resonance phenomena (an essentially atomic phenomenon) from the perspective of a condensed matter physicist with an interest in the optical properties of matter. As we shall see, this amounts to a particular prejudice about how one should think about many-body effects in a system of interacting electrons. Some of these effects are special to condensed matter systems and will be dealt with in the second half of this paper. However, it turns out that the authors view of the main ingredient to a giant resonance differs significantly from that normally taken by scientists trained in the traditional methods of atomic physics. Therefore, in the first section the author will take advantage of the fact that his contribution to this volume was composed and delivered to the publishers somewhat after the conclusion of the School (rather than before as requested by the organizers) and try to clearly distinguish the differences of opinion presented by the lecturers from the unalterable experimental facts. 46 references, 9 figures

  5. Decay of giant resonance E2 isoscalar in heavy nuclei

    International Nuclear Information System (INIS)

    Herdade, S.B.

    1980-01-01

    In this work, it is made a study of the giant resonance E2 isoscalar, in heavy nuclei. Fission probabilities for this resonance were determined by various authors, in different experiments, for 238 U. (A.C.A.S.) [pt

  6. Cardiac magnetic resonance imaging

    African Journals Online (AJOL)

    2011-03-06

    Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

  7. New properties of giant resonances in highly excited nuclei

    International Nuclear Information System (INIS)

    Morsch, H.P.

    1991-01-01

    Studies on the giant dipole resonance in very hot nuclei investigated in heavy ion-induced particle-γ coincidence experiments are reviewed. A signature is found in the γ-decay of excited nuceli which shows direct decay of the giant dipole resonance. This provides a new dimension in giant resonance studies and the possibility to study the dependence of giant resonance energy, width and sum rule strength on excitation energy and rotation of the system. Further, the fact that the giant resonance splits in deformed nuclei provides a unique way to get information on the shape of hot nuclei. First results are obtained on the following questions: (i)What is the nuclear shape at high temperature (T≥2 MeV)? (ii)Is there a phase transition in the nuclear shape at T∼1.7 MeV? (iii)Does motional narrowing exist in hot nuclei? (author). 19 refs., 11 figs

  8. Semimicroscopic description of the giant quadrupole resonances in deformed nuclei

    International Nuclear Information System (INIS)

    Kurchev, G.; Malov, L.A.; Nesterenko, V.O.; Soloviev, V.G.

    1976-01-01

    The calculation results of the giant quadrupole isoscalar and isovector resonances performed within the random phase approximation are represented. The strength functions for E2-transitions are calculated for doubly even deformed nuclei in the regions 150 (<=) A < 190 and 228 (<=) A < 248 in the energy interval (0-40) MeV. The following integral characteristics of giant quadrupole resonances are obtained: the position, widths, the contribution to the energy weighted sum rule and the contribution to the total cross section of photoabsorption. The calculations have shown that giant quadrupole resonances are common for all the considered nuclei. The calculated characteristics of the isoscalar giant quadrupole resonance agree with the available experimental data. The calculations also show that the semimicroscopic theory can be successfully applied for the description of giant multipole resonances

  9. Nuclear isovector giant resonances excited by pion single charge exchange

    International Nuclear Information System (INIS)

    King, B.H.

    1993-07-01

    This thesis is an experimental study of isovector giant resonances in light nuclei excited by pion single charge exchange reactions. Giant dipole resonances in light nuclei are known to be highly structured. For the mass 9 and 13 giant dipole resonances, isospin considerations were found to be very important to understanding this structure. by comparing the excitation functions from cross section measurements of the (π + , π 0 ) and (π, π 0 ) inclusive reactions, the authors determined the dominant isospin structure of the analog IVGR's. The comparison was made after decomposing the cross section into resonant and non-resonant components. This decomposition is made in the framework of strong absorption and quasi-free scattering. Measurements in the region of the isovector giant dipole resonances (IVGDR) were made to cover the inclusive angular distributions out to the second minimum. Study of the giant resonance decay process provides further understanding of the resonances. This study was carried out by observing the (π + , π 0 p) coincident reactions involving the resonances of 9 B and 13 N excited from 9 Be and 13 C nuclei. These measurements determined the spectra of the decay protons. This method also permitted a decomposition of the giant resonances into their isospin components. The multipolarities of the resonances were revealed by the decay proton angular correlations which, for dipoles, are of the form 1 + A 2 P 2 (cos θ)

  10. Features of the giant E1 resonance

    International Nuclear Information System (INIS)

    Bergere, R.

    1976-01-01

    Since most of the available experimental data concerning the giant dipole E1 resonance (GDR) have been obtained with real photons, the characteristics of real photon sources are reviewed with an attempt to connect the experimental particularities of each of them to the specific parameters of the GDR which it is best suited to reach. Some systematic properties gathered from experimental data of GDR (average energy, splitting and broadening of the GDR) are compared with the predictions of the static and dynamic collective models of the nuclei. The position in energy and the fine structure of the GDR are more closely connected to shell model predictions as nuclei get lighter, the various experimental integrated cross sections being also more easily understood by comparisons with microscopic models. Most of the reported data refer to the doorway state through which GDR is excited, however the competition between the decay channels for GDR states is also emphasized

  11. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  12. Nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Ethier, R.; Melanson, D.; Peters, T.M.

    1983-01-01

    Ten years following computerized tomography, a new technique called nuclear magnetic resonance revolutionizes the field of diagnostic imaging. A major advantage of nuclear magnetic resonance is that the danger of radiation is non-existent as compared to computerized tomography. When parts of the human body are subject to radio-frequencies while in a fixed magnetic field, its most detailed structures are revealed. The quality of images, the applications, as well as the indications are forever increasing. Images obtained at the level of the brain and spinal cord through nuclear magnetic resonance supercede those obtained through computerized tomography. Hence, it is most likely that myelography, along with pneumoencephalography will be eliminated as a diagnostic means. It is without a doubt that nuclear magnetic resonance is tomorrow's computerized tomography [fr

  13. Surface Magnetic Fields on Giants and Supergiants

    Science.gov (United States)

    Lebre, Agnès

    2018-04-01

    After a short introduction to spectropolarimetry and the tecnics allowing for the detection of surface fields, I will review the numerous and various detections of magnetic fields at the surface of giant and supergiant stars. On Betelgeuse, the prototype of Red Supergiants, I will present recent results collected after a 10 years long spectropolarimetric survey.

  14. Magnetic Resonance (MR) Defecography

    Science.gov (United States)

    ... to a CD or uploaded to a digital cloud server. Magnetic resonance (MR) defecography is a special ... with you. top of page What are the benefits vs. risks? Benefits MR defecography helps assess pelvic ...

  15. Magnetic resonance angiography (MRA)

    International Nuclear Information System (INIS)

    Arlart, I.P.; Guhl, L.

    1992-01-01

    An account is given in this paper of the physical and technical principles underlying the 'time-of-flight' technique for imaging of vessels by magnetic resonance tomography. Major indications for the new procedure of magnetic resonance angiography at present are intracerebral and extracerebral vessels, with digital subtraction angiography quite often being required to cope with minor alterations (small aneurysms, small occlusions). Magnetic resonance angiography and digital subtraction angiography are compared to each other for advantages and disadvantages. Basically, replacement of radiological angiography by magnetic resonance angiography appears to be possible only within limits, since X-ray diagnostics primarily provides morphological information about vessels, whereas flow dynamics is visualized by the 'time-of-flight' technique. (orig.) [de

  16. Magnetic Resonance Cholangiopancreatography (MRCP)

    Science.gov (United States)

    ... radio waves and a computer to evaluate the liver, gallbladder, bile ducts, pancreas and pancreatic duct for disease. It is ... of the hepatobiliary and pancreatic systems, including the liver, gallbladder, bile ducts, pancreas and pancreatic duct . Magnetic resonance imaging (MRI) ...

  17. Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Robert H. Morris

    2014-11-01

    Full Text Available Magnetic Resonance finds countless applications, from spectroscopy to imaging, routinely in almost all research and medical institutions across the globe. It is also becoming more frequently used for specific applications in which the whole instrument and system is designed for a dedicated application. With beginnings in borehole logging for the petro-chemical industry Magnetic Resonance sensors have been applied to fields as varied as online process monitoring for food manufacture and medical point of care diagnostics. This great diversity is seeing exciting developments in magnetic resonance sensing technology published in application specific journals where they are often not seen by the wider sensor community. It is clear that there is enormous interest in magnetic resonance sensors which represents a significant growth area. The aim of this special edition of Sensors was to address the wide distribution of relevant articles by providing a forum to disseminate cutting edge research in this field in a single open source publication.[...

  18. Magnetic resonance angiography

    Science.gov (United States)

    ... Saunders; 2015:chap 17. Litt H, Carpenter JP. Magnetic resonance imaging. In: Cronenwett JL, Johnston KW, eds. Rutherford's Vascular Surgery . 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap ...

  19. Spin isovector giant resonances in (n,p) reactions

    International Nuclear Information System (INIS)

    Spicer, B.M.

    1997-01-01

    The present status of the study of spin-flip isovector giant resonances, using the (n,p) charge exchange reaction, is reviewed. After a brief history of the discovery of these giant resonances, a critical appraisal of the interpretation of the data in terms of giant resonances is given, along with some of the theoretical advances that impact on the interpretation of these data. A sampling of the results obtained for typical targets is given, followed by the interpretation of these results. A brief statement is made concerning the way forward in experimental technique for nuclear structure research using charge exchange reactions

  20. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Robertson, Angus

    1990-01-01

    An assessment is made of the clinical benefits of expensive diagnostic technology, such as the magnetic resonance imaging. It is concluded that to most radiologists, magnetic resonance imaging has a definite place in the diagnostic scenario, especially for demonstrating central nervous system lesions in multiple sclerosis. While it is recognized that medical and financial resources are limited, it is emphasised that the cost to society must be balanced against the patient benefit. 17 refs

  1. Nuclear magnetic resonance gyroscope

    International Nuclear Information System (INIS)

    Grover, B.C.

    1984-01-01

    A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor

  2. Nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Young, I.R.

    1984-01-01

    In a method of imaging a body in which nuclear magnetic resonance is excited in a region including part of the body, and the free induction decay signal is measured, a known quantity of a material of known nuclear magnetic resonance properties, for example a bag of water, is included in the region so as to enhance the measured free induction decay signal. This then reduces the generation of noise during subsequent processing of the signal. (author)

  3. Laser magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Ferrari, C.A.

    1985-01-01

    The technique of laser resonance magnetic resonance allows one to study the high-resolution spectroscopy of transient paramagnetic species, viz, atoms, radicals, and molecular ions. This article is a brief exposition of the method, describing the principles, instrumentation and applicability of the IR and FIR-LMR and shows results of HF + . (Author) [pt

  4. Nuclear Magnetic Resonance Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 1. Nuclear Magnetic Resonance Spectroscopy. Susanta Das. General Article Volume 9 Issue 1 January 2004 pp 34-49. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/01/0034-0049. Keywords.

  5. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Magnetic resonance imaging (MRI) is a new and innovative technique that affords anatomic images in multiple planes and that may provide information about tissue characterization. The magnetic resonance images are obtained by placing the patient or the area of interest within a powerful, highly uniform, static magnetic field. Magnetized protons (hydrogen nuclei) within the patient align like small magnets in this field. Radiofrequency pulses are then used to create an oscillating magnetic field perpendicular to the main field. Magnetic resonance images differ from those produced by x-rays: the latter are associated with absorption of x-ray energy while magnetic resonance images are based on proton density and proton relaxation dynamics. Proton characteristics vary according to the tissue under examination and reflect its physical and chemical properties. To resolve issues regarding safety and efficacy, the Warren Grant Magnuson Clinical Center and the Office of Medical Applications of Research of the National Institutes of Health (NIH) convened a consensus conference about MRI Oct 26 through 28, 1987. At the NIH, the Consensus Development Conference brings together investigators in the biomedical sciences, clinical investigators, practicing physicians, and consumer and special interest groups to make a scientific assessment of technologies, including drugs, devices, and procedures, and to seek agreement on their safety and effectiveness

  6. Excitation of giant resonances via charge exchange reactions

    International Nuclear Information System (INIS)

    Goodman, C.D.

    1979-01-01

    Charge-exchange reactions can be useful for identifying isovector resonances. At present the most promising use of charge-exchange reactions with respect to giant resonances is to locate and study Gamow-Teller (GT) resonances. Detailed comparisons between GT and M1 strengths can yield further structure information. 7 figures

  7. Nuclear magnetic resonance apparatus

    International Nuclear Information System (INIS)

    Lambert, R.

    1991-01-01

    In order to include the effect of a magnetic object in a subject under investigation, Nuclear Magnetic Resonance (NMR) apparatus is operable at more than one radio frequency (RF) frequency. The apparatus allows normal practice as far as obtaining an NMR response or image from a given nuclear species is concerned, but, in addition, interrogates the nuclear spin system at a frequency which is different from the resonance frequency normally used for the given nuclear species, as determined from the applied magnetic field. The magnetic field close to a magnetised or magnetisable object is modified and the given nuclear species gives a response at the different frequency. Thus detection of a signal at the frequency indicates the presence of the chosen nuclei close to the magnetised or magnetisable object. Applications include validation of an object detection or automatic shape inspection system in the presence of magnetic impurities, and the detection of magnetic particles which affect measurement of liquid flow in a pipe. (author)

  8. Nuclear elasticity applied to giant resonances of fast rotating nuclei

    International Nuclear Information System (INIS)

    Jang, S.; Bouyssy, A.

    1987-06-01

    Isoscalar giant resonances in fast rotating nuclei are investigated within the framework of nuclear elasticity by solving the equation of motion of elastic nuclear medium in a rotating frame of reference. Both Coriolis and centrifugal forces are taken into account. The nuclear rotation removes completely the azimuthal degeneracy of the giant resonance energies. Realistic large values of the angular velocity, which are still small as compared to the giant resonance frequencies, are briefly reviewed in relation to allowed high angular momenta. It is shown that for the A=150 region, the Coriolis force is dominating for small values (< ∼ 0.05) of the ratio of angular velocity to resonance frequency, whereas the centrifugal force plays a prominent part in the shift of the split resonance energies for larger values of the ratio. Typical examples of the resonance energies and their fragmentation due to both rotation and deformation are given

  9. Fluid dynamics of giant resonances on high spin states

    International Nuclear Information System (INIS)

    Di Nardo, M.; Di Toro, M.; Giansiracusa, G.; Lombardo, U.; Russo, G.

    1983-01-01

    We describe giant resonances built on high spin states along the yrast line as scaling solutions of a linearized Vlasov equation in a rotating frame obtained from a TDHF theory in phase space. For oblate cranked solutions we get a shift and a splitting of the isoscalar giant resonances in terms of the angular velocity. Results are shown for 40 Ca and 168 Er. The relative CM strengths are also calculated. (orig.)

  10. Giant resonances in free atoms and in clusters

    International Nuclear Information System (INIS)

    Brechignac, C.; Connerade, J.P.

    1994-01-01

    A review of recent developments in the study of giant resonances in free atoms and in clusters is presented, with particular emphasis on the transition from free atoms to atoms in the condensed phase. Giant resonances in alkali and related metallic clusters due to the excitation of closed shells of delocalized electrons are also reviewed and the relation between different types of collective oscillations is discussed. (author)

  11. Direct vs statistical decay of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Carlson, B.V.; Merchant, A.C.; Adhikari, S.K.

    1986-01-01

    A theoretical framework for the description of the decay of giant multipole resonances id developed. Besides the direct decay, both the pre-equilibrium and statistical (compound) decays are taken into account in a consistent way. It is shown that the statistical decay of the giant resonance is not necessarily described by the Hauser-Feshbach theory owing to the presence of a mixing parameter, which measures the degree of fragmentation. Applications are made to several cases. (Author) [pt

  12. Giant 4p-quadrupole resonances in the Rare Earths

    International Nuclear Information System (INIS)

    Matthew, J.A.D.; Netzer, F.P.; Clark, C.W.; Morar, J.F.

    1987-01-01

    X-ray absorption of Ce obtained by partial secondary yield, is compared with previously obtained electron-energy loss measurements in reflection mode. The absence of a strong feature below 4p 3/2 threshold in photon absorption provides confirmation that the peak in EELS is nondipole in character. Theoretical analysis supports interpretation in terms of a p-f giant quadrupole resonance, a result which broadens the analogy between giant resonances in atomic and nuclear physics

  13. Giant dipole resonance in hot rotating nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, D.R. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Dinh Dang, N. [RIKEN, Nishina Centre for Accelerator-based Science, Saitama (Japan); VINATOM, Institute of Nuclear Science and Technique, Hanoi (Viet Nam); Datar, V.M. [Tata Institute of Fundamental Research, INO Cell, Mumbai (India)

    2016-05-15

    Over the last several decades, extensive experimental and theoretical work has been done on the giant dipole resonance (GDR) in excited nuclei covering a wide range of temperature (T), angular momentum (J) and nuclear mass. A reasonable stability of the GDR centroid energy and an increase of the GDR width with T (in the range∝1-3 MeV) and J are the two well-established results. Some experiments have indicated the saturation of the GDR width at high T. The gradual disappearance of the GDR vibration at much higher T has been observed. Experiments on the Jacobi transition and the GDR built on superdeformed shapes at high rotational frequencies have been reported in a few cases. Theoretical calculations on the damping of the collective dipole vibration, characterised by the GDR width, have been carried out within various models such as the thermal shape fluctuation model and the phonon damping model. These models offer different interpretations of the variation of the GDR width with T and J and have met with varying degrees of success in explaining the experimental data. In this review, the present experimental and theoretical status in this field is discussed along with the future outlook. The interesting phenomenon of the pre-equilibrium GDR excitation in nuclear reactions is briefly addressed. (orig.)

  14. Giant resonances in atoms and in fluorine cage molecules

    International Nuclear Information System (INIS)

    Mansfield, M.W.D.

    1987-01-01

    Giant resonances in the photoabsorption spectra of atoms occur in the extreme ultraviolet region of the electromagnetic spectrum. In order to observe absorption spectra in this region it is necessary to generate columns of atomic vapor which will often by very hot and chemically aggressive, and to contain them without solid windows between two regions of high vacuum, the spectrometer and the light source, usually an electron synchrotron. The technical problems are often formidable so that although it had long been recognized that giant resonances in solid lanthanides were essentially atomic phenomena (Fomichev et al. 1967, Dehmer et al. 1971) earlier investigations of giant resonances in atoms were limited to the more manageable elements which precede the transition rows, the inert gases, alkali and alkaline earth elements. In this paper the authors discusses the spectra of transition row atoms in order of decreasing localization (Smith and Kmetko 1983) viz. 4d → f, 5d → f, 3p → d, 4p → d and 5p → d. He tends to avoid discussion of the giant resonances themselves because their profiles and interpretation will be discussed comprehensively by other contributors. Instead he concentrates on the detailed analyses which have been attempted of the discrete structure which usually accompanies giant resonances in atoms. Interpretation of this structure can provide accurate determinations of thresholds for inner shell excitation in atoms and can also be used to anticipate structure which may overlie the giant resonances and distort their profiles. 75 references, 21 figures

  15. Excitation and photon decay of giant multipole resonances

    International Nuclear Information System (INIS)

    Bertrand, F.E.; Beene, J.R.

    1990-01-01

    A brief review of the excitation of giant multipole resonances via Coulomb excitation is given which emphasizes the very large cross sections that can be realized through this reaction for both isoscalar and isovector resonances. Discussion and results where available, are provide for the measurement of the photon decay of one and two phonon giant resonances. It is pointed out throughout the presentation that the use of E1 photons as a ''tag'' provides a means to observe weakly excited resonances that cannot be observed in the singles spectra. 14 refs., 12 figs., 1 tab

  16. Nuclear magnetic resonance scattering

    International Nuclear Information System (INIS)

    Young, I.R.

    1985-01-01

    A nuclear magnetic resonance apparatus is described including a magnet system which is capable of providing a steady magnetic field along an axis, and is constructed so as to define a plurality of regions along the axis in each of which the field is substantially homogeneous so that in each region an imaging operation may be separately carried out. Iron shields increase the field homogeneity. In use, each patient lies on a wheeled trolley which is provided with magnetic field gradient coils and an RF coil system, some of the coils being movable to facilitate positioning of the patient, and there are terminals for connection to a common computing and control facility. (author)

  17. Magnetic resonance annual, 1988

    International Nuclear Information System (INIS)

    Kressel, H.Y.

    1987-01-01

    This book features reviews of high-resolution MRI of the knee, MRI of the normal and ischmeic hip, MRI of the heart, and temporomandibular joint imaging, as well as thorough discussion on artifacts in magnetic resonance imaging. Contributors consider the clinical applications of gadolinium-DTPA in magnetic resonance imaging and the clinical use of partial saturation and saturation recovery sequences. Timely reports assess the current status of rapid MRI and describe a new rapid gated cine MRI technique. Also included is an analysis of cerebrospinal fluid flow effects during MRI of the central nervous system

  18. Advances in magnetic resonance 10

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.

  19. Imaging by magnetic resonance

    International Nuclear Information System (INIS)

    Duroure, J.F.; Serpolay, H.; Vallens, D.

    1995-01-01

    Here are described the advanced technology for nuclear magnetic resonance imaging: reduction of acquisition times, and rebuilding times, images quality improvement. The tendency is to open the machines at low and middle field, on a market being at 10% of NMR I sales, with economical, scientifical and ergonomic reasons broadly developed by constructors

  20. Magnetic resonance fingerprinting.

    Science.gov (United States)

    Ma, Dan; Gulani, Vikas; Seiberlich, Nicole; Liu, Kecheng; Sunshine, Jeffrey L; Duerk, Jeffrey L; Griswold, Mark A

    2013-03-14

    Magnetic resonance is an exceptionally powerful and versatile measurement technique. The basic structure of a magnetic resonance experiment has remained largely unchanged for almost 50 years, being mainly restricted to the qualitative probing of only a limited set of the properties that can in principle be accessed by this technique. Here we introduce an approach to data acquisition, post-processing and visualization--which we term 'magnetic resonance fingerprinting' (MRF)--that permits the simultaneous non-invasive quantification of multiple important properties of a material or tissue. MRF thus provides an alternative way to quantitatively detect and analyse complex changes that can represent physical alterations of a substance or early indicators of disease. MRF can also be used to identify the presence of a specific target material or tissue, which will increase the sensitivity, specificity and speed of a magnetic resonance study, and potentially lead to new diagnostic testing methodologies. When paired with an appropriate pattern-recognition algorithm, MRF inherently suppresses measurement errors and can thus improve measurement accuracy.

  1. Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  2. Nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Rueterjans, H.

    1987-01-01

    Contributions by various authors who are working in the field of NMR imaging present the current status and the perspectives of in-vivo nuclear magnetic resonance spectroscopy, explaining not only the scientific and medical aspects, but also technical and physical principles as well as questions concerning practical organisation and training, and points of main interest for further research activities. (orig./TRV) [de

  3. Nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    1983-06-01

    This report summarises the aspects of nuclear magnetic resonance imaging (NMRI) considered by the National Health Technology Advisory Panel and makes recommendations on its introduction in Australia with particular regard to the need for thorough evaluation of its cost effectiveness. Topics covered are: principles of the technique, equipment required, installation, costs, reliability, performance parameters, clinical indications, training and staff requirements, and safety considerations

  4. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association ... MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging ( ...

  5. Magnetic Resonance Imaging (MRI) Safety

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining ...

  6. Magnetic Resonance Imaging of Stroke

    NARCIS (Netherlands)

    Bouts, Mark. J. R. J.; Wu, O.; Dijkhuizen, R. M.

    2017-01-01

    Magnetic resonance imaging (MRI) provides a powerful (neuro)imaging modality for the diagnosis and outcome prediction after (acute) stroke. Since MRI allows noninvasive, longitudinal, and three-dimensional assessment of vessel occlusion (with magnetic resonance angiography (MRA)), tissue injury

  7. Magnetic resonance of phase transitions

    CERN Document Server

    Owens, Frank J; Farach, Horacio A

    1979-01-01

    Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

  8. New results on multiple excitations of giant resonances

    International Nuclear Information System (INIS)

    Mordechai, S.; Texas Univ., Austin, TX; Moore, C.F.

    1993-01-01

    Exotic excitations like the double giant dipole were predicted for many years but not observed experimentally until recently. Several experiments have been carried out at Los Alamos National laboratory to search for these new collective modes of the nucleus. The results discover two previously unobserved types of double giant resonances. This work presents the recent pion double charge exchange data and the analysis that support the existence of two such exotic vibrational nuclear modes

  9. Children's (Pediatric) Magnetic Resonance Imaging

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

  10. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  12. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging ( ... the limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a ...

  13. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  14. Recent Results From Skyrme-TDHF: Giant Resonances and Collisions

    International Nuclear Information System (INIS)

    Stevenson, Paul D.

    2007-01-01

    Using fully three-dimensional Time-Dependent Hartree-Fock with Skyrme forces allows one to explore small and large amplitude collective motion in nuclei using only an effective interaction fitted to ground state and nuclear matter properties as input. In this talk, results are presented for TDHF calculations of giant resonances and nuclear collisions. We examine deformation splitting of the giant dipole resonance on ground and excited intrinsic superdeformed states, showing the interplay between Landau splitting and deformation splitting, including effects of triaxiality[1]. In the case of giant monopole resonances, isospin-mixing is examined, showing that the isovector and isoscalar parts of strength functions are strongly coupled [2]. The role of absorption in the TDHF approach to linear and nonlinear regimes is examined[3]. Calculations of nuclear collisions are also explored, showing that the effects of fully relaxed symmetry produce new modes of energy loss not found in previous calculations [4]. (Author)

  15. The direct neutron decay of giant resonances in 208Pb

    International Nuclear Information System (INIS)

    Bracco, A.

    1988-01-01

    The neutron decay of the giant multipole resonance region from 9 to 15 MeV of excitation energy in 208 Pb has been studied. Neutron branching ratios for the decay to the ground state and to the low-lying excited states of 207 Pb were measured as a function of the excitation energy of 208 Pb and compared to Hauser-Feshbach calculations. While the neutron branching ratios from the energy region of the isoscalar giant quadrupole resonance are reproduced by the calculations, the ratios from the energy region of the isoscalar giant monopole resonance show a conspicuous excess with respect to the statistical model predictions. The neutron yield from this energy region was analysed in terms of a multistep model of the compound nucleus which includes collective doorway channels. The total direct escape width as well as the associated direct partial escape widths to the lowest five valence hole states of 207 Pb were determined. (orig.)

  16. Giant monopole resonance in transitional and deformed nuclei

    International Nuclear Information System (INIS)

    Garg, U.; Bogucki, P.; Bronson, J.D.; Lui, Y.; Youngblood, D.H.

    1984-01-01

    Small-angle inelastic α-scattering measurements have been made at E/sub α/ = 129 MeV on /sup 144,148/Sm and /sup 142,146,150/Nd to investigate the giant monopole resonance in transitional and deformed nuclei. The experimental data reveal a mixing of L = 0 and L = 2 modes in 148 Sm resulting in almost identical angular distributions for the two components of the giant resonance peaks in the angular range 2 0 --6 0 . A ''splitting'' of the giant monopole resonance is observed in 150 Nd; the extent of this splitting is smaller than that reported for 154 Sm. Comparison is made with the predictions of various theoretical models

  17. Magnetic resonance instrumentation

    International Nuclear Information System (INIS)

    Bell, R.A.

    1987-01-01

    Magnetic resonance (MR), while opening new vistas to diagnostic medicine, utilizes equipment that is unfamiliar to most clinicians. Beyond learning to cope with new terms, such as spin-echo, T1, T2, and spin density, health care professionals are faced with the inclusion of magnetic and radiofrequency effects in their facilities produced by a complex array of devices. It is the purpose of this chapter to outline the components of an MR imaging system, to discuss their functions, and to note the variations in equipment commercially available

  18. Is There a Pronounced Giant Dipole Resonance in 4He?

    International Nuclear Information System (INIS)

    Efros, V.D.; Efros, V.D.; Leidemann, W.; Orlandini, G.; Orlandini, G.

    1997-01-01

    A four-nucleon calculation of the total 4 He photodisintegration cross section is performed. The full final-state interaction is taken into account for the first time. This is achieved via the method of the Lorentz integral transform. Semirealistic NN interactions are employed. Different from the known partial two-body 4 He( γ,n) 3 He and 4 He( γ,p) 3 H cross sections our total cross section exhibits a pronounced giant resonance. Thus, in contrast to older (γ,np) data, we predict quite a strong contribution of the (γ,np) channel at the giant resonance peak energy. copyright 1997 The American Physical Society

  19. Hybrid model for the decay of nuclear giant resonances

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1986-12-01

    The decay properties of nuclear giant multipole resonances are discussed within a hybrid model that incorporates, in a unitary consistent way, both the coherent and statistical features. It is suggested that the 'direct' decay of the GR is described with continuum first RPA and the statistical decay calculated with a modified Hauser-Feshbach model. Application is made to the decay of the giant monopole resonance in 208 Pb. Suggestions are made concerning the calculation of the mixing parameter using the statistical properties of the shell model eigenstates at high excitation energies. (Author) [pt

  20. Relativistic Coulomb excitation of giant resonances in the hydrodynamic model

    International Nuclear Information System (INIS)

    Vasconcellos Gomes, Ana Cristina de.

    1990-05-01

    We investigate the Coulomb excitation of giant dipole resonances in relativistic heavy ion collisions using a macroscopic hydrodynamical model for the harmonic vibrations of the nuclear fluid. The motion is treated as a combination of the Goldhaber-Teller displacement mode and the Steinwedel-Jensen acoustic mode, and the restoring forces are calculated using the droplet model. This model is used as input to study the characteristics of multiple excitation of giant dipole resonances in nuclei. Possible signatures for the existence of such states are also discussed quantitatively. (author). 52 refs., 14 figs., 3 tabs

  1. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Sigal, R.

    1988-01-01

    This book is an introduction to magnetic resonance imaging (MRI). The basic principles for the interpretation of MR images are developed. The book is divided into five chapters: introduction, tissue, parameters, acquisition parameters, contribution to diagnosis, and practical management of an MR examination. Eight exercises allow the reader to test the knowledge he has acquired. Signal localization and MR artefacts are reviewed in an appendix

  2. Magnetic resonance imaging (MRI

    Directory of Open Access Journals (Sweden)

    Takavar A

    1993-04-01

    Full Text Available Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I, a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D. factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

  3. Magnetic resonance imaging (MRI)

    OpenAIRE

    Takavar A

    1993-01-01

    Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I), a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D.) factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

  4. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed ... problems, medications, recent surgeries and allergies. The magnetic field is not harmful, but it may cause some ...

  5. A Boltzmann equation approach to the damping of giant resonances in nuclei

    International Nuclear Information System (INIS)

    Schuck, P.; Winter, J.

    1983-01-01

    The Vlasov equation plus collision term (Boltzmann equation) represents an appropriate frame for the treatment of giant resonances (zero sound modes) in nuclei. With no adjustable parameters we obtain correct positions and widths for the giant quadrupole resonances. (author)

  6. A self-consistent semiclassical sum rule approach to the average properties of giant resonances

    International Nuclear Information System (INIS)

    Li Guoqiang; Xu Gongou

    1990-01-01

    The average energies of isovector giant resonances and the widths of isoscalar giant resonances are evaluated with the help of a self-consistent semiclassical Sum rule approach. The comparison of the present results with the experimental ones justifies the self-consistent semiclassical sum rule approach to the average properties of giant resonances

  7. Introduction lecture to magnetic resonance

    International Nuclear Information System (INIS)

    Conard, J.

    1980-01-01

    This lecture deals with all that is common either to electron paramagnetic resonance (E.P.R.) or to nuclear magnetic resonance (N.M.R.). It will present, in an as elementary form as possible, the main concepts used in magnetic resonance emphasizing some aspects, specific for interface science. (orig./BHO)

  8. Structure of the giant dipole resonance in 208Pb

    International Nuclear Information System (INIS)

    El Naggar, N.M.

    1977-01-01

    A new scheme is devised to study the giant resonance in the heavy magic nucleus 208 Pb. The effect of the 4 + and 5 - collective excitations of the nucleus core is demonstrated. The calculated cross section is compared with the experimental data. (author)

  9. A sum rule description of giant resonances at finite temperature

    International Nuclear Information System (INIS)

    Meyer, J.; Quentin, P.; Brack, M.

    1983-01-01

    A generalization of the sum rule approach to collective motion at finite temperature is presented. The m 1 and msub(-1) sum rules for the isovector dipole and the isoscalar monopole electric modes have been evaluated with the modified SkM force for the 208 Pb nucleus. The variation of the resulting giant resonance energies with temperature is discussed. (orig.)

  10. Advanced Nuclear Magnetic Resonance

    OpenAIRE

    Alonso, Diego A.

    2014-01-01

    Transparencias en inglés de la asignatura "Resonancia Magnética Nuclear Avanzada" (Advanced Nuclear Magnetic Resonance) (36643) que se imparte en el Máster de Química Médica como asignatura optativa de 3 créditos ECTS. En esta asignatura se completa el estudio iniciado en la asignatura de quinto curso de la licenciatura en Química "Determinación estructural" (7448) y en la del Grado de Química de tercer curso "Determinación estructural de los compuestos orgánicos" (26030) en lo referente a té...

  11. Cranial magnetic resonance imaging

    International Nuclear Information System (INIS)

    Elster, A.D.

    1988-01-01

    Cranial Magnetic Resonance Imaging is comprehensive, well structured, and well written. The material is current and well referenced. The illustrations are good and complement the text well. The overall quality of publication is above average. The greatest attribute of the book is its readability. The author demonstrates ample skill in making complex subjects, such as MR physics and imaging of cerebral hemorrhage, easy to understand. The book closes with a detailed atlas on the anatomic appearance of the brain on MR images in the axial, coronal, and sagittal planes

  12. Dental magnetic resonance imaging

    International Nuclear Information System (INIS)

    Hilgenfeld, Tim; Bendszus, Martin; Haehnel, Stefan

    2016-01-01

    Growing distribution and utilization of digital volume tomography (DVT) extend the spectrum of clinical dental imaging. Additional diagnostic value, however, comes along with an increasing amount of radiation. In contrast, magnetic resonance imaging is a radiation free imaging technique. Furthermore, it offers a high soft tissue contrast. Morphological and numerical dental anomalies, differentiation of periapical lesions and exclusion of complications of dental diseases are field of applications for dental MRI. In addition, detection of caries and periodontal lesions and injury of inferior alveolar nerve are promising application areas in the future.

  13. Nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Cremin, B.J.

    1981-01-01

    Recent advances in diagnostic imaging, have been the medical application of nuclear magnetic resonance (NMR). It's been used to study the structure of various compounds in chemistry and physics, and in the mid-1970 to produce images of rabbits and eventually of the human hand and head. The images are produced by making use of the nuclear magnetization of the hydrogen ion, or proton, that is present in biological material to record the density distribution of protons in cellular water and lipids. An exploration of the end-results of complicated free induction decay signals, that have been digitized and frequency-analysed by mathematical computerized techniques to produce an image of tissue density, is given. At present NMR produces images comparable to those of early computed tomography

  14. Studies of the giant resonances in heavy nuclei

    International Nuclear Information System (INIS)

    Cataldi, M.I.C.

    1986-01-01

    Experimental measurements of the eletrodisintegration cross section in 181 Ta, 208 Pb and 209 Bi nuclei are made in the Linear Accelerator of the IFUSP-Brazil. The cross section is obtained by the direct counting of the emitted neutrons, in an electron excitation energy range between 8 to 22 MeV. The experimental data are analysed throught the virtual photon method, with the aim of obtaining the isoscalar and isovectorial electric quadrupole giant resonance (E2GR) intensities, as well as the magnetic dipole intensity. For each studied nucleus the results obtained for the E2GR, isoscalar and isovectorial, are compared with the photodisintegration cross section measured by the Saclay and Livermore laboratories. From this comparison, it is observed that the photodisintegration cross sections are compatibles with the existence of an isovector E2GR, located between 120 to 130 A -1/3 Mev and which exhaust around 100% of the Energy-Weighted Sum rules (EWSR). (L.C.) [pt

  15. Advances in magnetic resonance 11

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 11, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters and begins with a discussion of the principles and applications of dynamic nuclear polarization, with emphasis on molecular motions and collisions, intermolecular couplings, and chemical interactions. Subsequent chapters focus on the assessment of a proposed broadband decoupling method and studies of time-domain (or Fourier transform) multiple-quantum nuclear magnetic resonance.

  16. Isovector giant monopole resonances: A sum-rule approach

    International Nuclear Information System (INIS)

    Goeke, K.; Bonn Univ.; Castel, B.

    1980-01-01

    Several useful sum rules associated with isovector giant monopole resonances are calculated for doubly closed shell nuclei. The calculation is based on techniques known from constrained and adiabatic time-dependent Hartree-Fock theories and assume various Skyrme interactions. The results obtained form, together with the compiled literature, the basis for a quantitative description of the RPA strength distribution in terms of energy-weighted moments. These, together with strength distribution properties, are determined by a hierarchy of determinantal relations between moments. The isovector giant monopole resonance turns out to be a rather broad resonance centered at E = 46 Asup(-1/10) MeV with an extended width of more than 16 MeV. The consequences regarding isospin impurities in the nuclear ground state are discussed. (orig.)

  17. The natural line shape of the giant dipole resonance

    International Nuclear Information System (INIS)

    Gordon, E.F.; Pitthan, R.

    1977-01-01

    Investigation of photoabsorption experiments in the spherical nucleus 141 Pr, the quasispherical dynamically deformed 197 Au, and the statically deformed 165 Ho showed that the function which describes best the energy dependence of the reduced transition probability is given by the Breit-Wigner form rather than the Lorentz form. However, the form of the resulting measured cross section is approximately of the Lorentz type. The dependence of the giant resonance width GAMMA on the excitation energy was also investigated, and found to be less than 1% per MeV if one considered the known isovector E2 resonance above the giant dipole resonance. Best fit values of the reduced transition probabilities for the three nuclei are given and compared to (e,e') results. (Auth.)

  18. Electromagnetic excitation of the two-phonon giant dipole resonance

    International Nuclear Information System (INIS)

    Emling, H.

    1994-03-01

    It is the aim of this article to summarize our present knowledge on the double isovector giant dipole resonance (DGDR) and our understanding of the electromagnetic excitation mechanism in heavy ion collisions in the relativistic energy regime. In the following chapter, a brief resume on the history of giant resonances is given and, based on their understanding, conclusions on the expected properties of multi-phonon resonances are drawn. In chapter 2, the essential features of electromagnetic heavy ion interactions at (near) relativistic velocities will be illuminated and the theoretical framework is presented, which describes such processes. New experimental methods were required for an appropriate study of Coulomb dissociation processes, which are discussed in chapter 3 together with the experimental results. Chapter 4 is dedicated to summarize the results from electromagnetic excitation studies, to compare with those from alternative methods and, in particular, to contrast experimental findings with theoretical predictions and to address open problems. (orig.)

  19. Nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Rabenstein, D.L.; Guo, W.

    1988-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most widely used instrumental methods, with applications ranging from the characterization of pure compounds by high-resolution NMR to the diagnosis of disease by magnetic resonance imaging (MRI). To give some idea of the wide-spread use of NMR, a computer search for the period 1985-1987 turned up over 500 books and review articles and over 7000 literature citations, not including papers in which NMR was used together with other spectroscopic methods for the routine identification of organic compounds. Consequently, they have by necessity been somewhat selective in the topics they have chosen to cover and in the articles they have cited. In this review, which covers the published literature for the approximate period Sept 1985-Aug 1987, they have focused on new developments and applications of interest to the chemist. First they review recent developments in instrumentation and techniques. Although there have not been any major break-throughs in NMR instrumentation during the past two years, significant refinements have been reported which optimize instrumentation for the demanding multiple pulse experiments in routine use today. Next they review new developments in methods for processing NMR data, followed by reviews of one-dimensional and two-dimensional NMR experiments

  20. Collisional width of giant resonances and interplay with Landau damping

    International Nuclear Information System (INIS)

    Bonasera, A.; Burgio, G.F.; Di Toro, M.; Wolter, H.H.

    1989-01-01

    We present a semiclassical method to calculate the widths of giant resonances. We solve a mean-field kinetic equation (Vlasov equation) with collision terms treated within the relaxation time approximation to construct a damped strength distribution for collective motions. The relaxation time is evaluated from the time evolution of distortions in the nucleon momentum distribution using a test-particle approach. The importance of an energy dependent nucleon-nucleon cross section is stressed. Results are shown for isoscalar giant quadrupole and octupole motions. A quite important interplay between self-consistent (Landau) and collisional damping is revealed

  1. Advances in magnetic resonance 6

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 6 focuses on the theoretical and practical aspects of applying magnetic resonance methods to various problems in physical chemistry, emphasizing the different aspects of the exegesis of these problems. This book discusses the gas phase magnetic resonance of electronically excited molecules; techniques for observing excited electronic states; NMR studies in liquids at high pressure; and effect of pressure on self-diffusion in liquids. The nuclear magnetic resonance investigations of organic free radicals; measurement of proton coupling constants by NMR; an

  2. Fragmentation of giant dipole resonance at finite temperature

    International Nuclear Information System (INIS)

    Vdovin, A.

    2005-01-01

    It is well known that the main part of a width of a collective giant resonance built on the ground state in heavy nuclei is due to coupling of one-phonon vibrational states with more complex ones like two phonon or two-particle - two-hole. So it seems natural that the same idea was also explored in studying of the formation and dependence on temperature of a width of giant resonances built on a compound nuclear state. The first microscopic calculations of a giant dipole resonance width at finite temperature have demonstrated its weak dependence on T whereas the experimental width Γ exp strongly increases up to T≤3 MeV. The observed thermal behaviour of Γ exp was attributed mainly to thermal fluctuations of a nuclear shape at finite T . However, further theoretical studies of the problem have shown a strengthening of the GDR spreading with T. We calculate a fragmentation of the giant dipole resonance in hot spherical nuclei within the approach based on the quasiparticle-phonon model extended to finite temperature in with the formalism of thermofield dynamics. The fragmentation of collective giant dipole vibrations at finite T is due to the coupling with 'two-thermal phonon' configurations. The energies and structures of thermal phonon states are calculated from the thermal RPA temperature dependence of the variance σ th of a theoretical E1 strength function and the experimental GDR width Γ exp in 120 Sn. The coupling of thermal phonons is determined by their fermionic structure. The variance σ th of the E1 strength function is found continuously increasing with temperature. The main reason of this behavior is the coupling of the dipole phonons with very low-lying particle-particle (hole-hole) thermal phonons. These phonons are noncollective ones and they appear only at T≠0. The calculated T dependence of σ th is quite similar to that of the experimental width Γ exp in 120 Sn and 208 Pb

  3. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... immediately after the exam. A few patients experience side effects from the contrast material, including nausea and local ... Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic ...

  4. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... by the interpreting radiologist. Frequently, the differentiation of abnormal (diseased) tissue from normal tissues is better with ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  5. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  6. Excitation of giant resonances through inelastic scattering of 170 at 84 MeV/u. Fission decay of giant resonances

    International Nuclear Information System (INIS)

    Cabot, C.; Barrette, J.; Mark, S.K.; Turcotte, R.; Xing, J.; Van der Woude, A.; Van Den Berg, A. M.

    1991-01-01

    Inelastic scattering of 84 MeV/u 17 0 projectiles have been used to excite the giant resonances (GR) in various nuclei ranging from A=60 to A=232. For the isoscalar giant quadrupole resonance (ISGQR), the energy and width of the resonance, as well as the EWSR obtained from the measured cross sections, are in agreement with the known systematics for A>40. The observed GMR strengths are close to 100% EWRS and are consistent with other recent experimental results using heavy ion projectiles. These results lead to a somewhat different picture than that provided by previous studies using light projectiles. Strength is also observed at high excitation energy. The analysis of these resonances is in progress. Our study of the fission decay of GR in 232 Th leads to a somewhat different conclusion than previously deduced from data obtained with light ion projectiles, where no evidence for the fission decay of the ISGQR has been found. In the present work, due to the very good peak-to-continuum ratio, a structure is observed in the fission coincidence spectrum around 10 MeV which can be attributed to the fission decay of giant resonances. The measured fission probability is consistent with a statistical decay of the ISGQR. 10 figs

  7. Study of giant multipole resonances in 40Ca

    International Nuclear Information System (INIS)

    Rost, H.

    1979-01-01

    In the present thesis giant resonance states in 40 Ca were studied by scattering of 104 MeV a particles on 40 Ca and by the reactions 39 K(p vector,p') 39 K and 39 K(p,α) 36 Ar. The scattered α-particles were measured at extreme forward angles (THETAsub(L) = 4 0 -16 0 C), because at forward angles the cross sections for the excitation of states with spin 0 and 1 strongly differ from those with higher spin. The aim of this experiment was first of all the study of the giant resonance region in 40 Ca on the contribution to 0 + or 1 - states. Beside the known electric giant quadrupole resonances at Esub(x) approx. equal to 18.5 MeV (25% EWSR) contributions of EO-strength at Esub(x) approx. equal to 21 MeV (6% EWSR) and indications to a (isoscalar) E1-strength at Esub(x) approx. equal to 14 MeV and Esub(x) approx. equal to 16 MeV were found. At the reactions 39 K(p vector,p') 39 K and 39 K(p,α) 36 Ar in the channels (p,p 0 ),(p,p 4 ), (p,αsub(o)), and (p,α 1 ) at incident energies at about 10 MeV (Esub(x)( 40 Ca) approx. equal to 18 MeV) resonant structures were observed. A scattering phase analysis performed for the elastic proton scattering didn't however yield quantitative results about the resonance parameter. An expansion of the cross sections by Legendre polynomials for the remaining reaction channel didn't allow a conclusion about the dominance of a certain L-value. The only indication to the connection of the observed resonant structures with the giant quadrupole resonance in 40 Ca is therefore the energetic position at about Esub(x) approx. equal to 18 MeV. Altogether the observed structures however were not very pronounced, so it can be concluded, that the excitation of the giant quadrupole resonance in 40 Ca by protons via the ground state of 39 K occurs not very strongly. (orig./HSI) [de

  8. Electron scattering studies of selected electric and magnetic dipole and quadrupole transitions in light and heavy nuclei, the new multipole giant resonances and atomic transitions - recent results from the DALINAC

    International Nuclear Information System (INIS)

    Richter, A.

    1977-01-01

    Recent experimental work from the Darmstadt electron linear accelerator (DALINAC) is briefly summarized. Particular emphasis is given to the following topics: high resolution inelastic electron scattering (ΔE approximately 30 keV FWHM) has been used to study the radiative width and magnetization density of the 2 + , T = 1 state at 16.11 MeV in 12 C, E2 strength distribution in 28 Si below an excitation energy of 13 MeV and the isospin forbidden E1 electroexcitation of the 1 - , T = 0 state at 6.95 MeV in 40 Ca. High resolution inelastic electron scattering was also employed to determine certain M1 transitions in 14 N, 28 Si, 39 K, 58 Ni, 90 Zr and 208 Pb and the M2 strength distribution in the two heaviest nuclei. At medium energy resolution (ΔE approximately 200 keV FWHM) spectra at various angles and bombarding energies have been measured from (4-31) MeV for 208 Pb. They are being analyzed in order to determine E0, E1, E2, E3 and M1 giant resonance strength in the continuum. The Z and E dependence and the scaling behaviour of the atomic inner shell ionization cross section at relativistic electron impact is studied on gaseous and solid targets. (orig./BJ) [de

  9. Magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Meyerhoff, D.J.; Weiner, M.W.

    1989-01-01

    A major function of the liver is regulation of carbohydrate, lipid, and nitrogen metabolism. Food is absorbed by the intestines and transported to the liver by the portal circulation. Substrates are metabolized and stored in the liver to maintain optimal blood concentrations of glucose and lipids. Ammonia generated in the gastrointestinal tract is converted to urea in the liver by the urea cycle. Various forms of liver disease are associated with disorders of carbohydrate, fat, and nitrogen metabolism. Therefore the ability to characterize liver metabolism noninvasively is of potential diagnostic value. Magnetic resonance spectroscopy (MRS) provides information about tissue metabolism by measuring concentrations of metabolites. However, to determine the anatomic location from which spectroscopic signals are derived, MRS could be performed in conjunction with MRI. This paper summarizes the current experience with spectroscopy ion animal models of human disease and reviews the clinical experience with hepatic MRS to date

  10. Magnetic resonance in neuroborreliosis

    International Nuclear Information System (INIS)

    Ustymowicz, A.; Zajkowska, J.

    2003-01-01

    Magnetic resonance (MR) is commonly used in diagnosing infections of the central nervous system. The aim of the study is to evaluate central nervous system changes in neuroborreliosis patients. MR examinations were performed in 44 patients with clinical symptoms, epidemiology and laboratory tests results of neuroborreliosis. Abnormalities were detected in 22 patients. Most of them presented cortico-subcortical atrophy (86%). In 9 cases foci of increased signal in T2-weighted and FLAIR images were observed in white matter. They were single or multiple, located subcorticaly and paraventriculary. In 2 subjects areas of increased signal were found in the brain stem. Central nervous system abnormalities detected with MR are not specific for Lyme disease. They can suggest demyelinating lesions and/or gliosis observed in many nervous system disorders (SM, ADEM, lacunar infarcts). (author)

  11. Cine magnetic resonance

    International Nuclear Information System (INIS)

    Higgins, C.B.; Sechtem, U.P.; Pflugfelder, P.

    1987-01-01

    Cine magnetic resonance (MR) is a fast MR imaging process with referencing of the imaging data to the electrocardiogram (ECG) so that images corresponding to 21-msec segments of the cardiac cycle are acquired. A series of such images, each corresponding to a 21-msec segment of the cardiac cycle, can be laced together for viewing in the cine format at a framing rate of 20 to 40 frames per second. Since cine angiograms of the heart are usually done at 30 frames per second, this technique achieves a temporal resolution adequate for the evluation of central cardiovascular function. The major application of this technique is to depict central cardiovascular function and blood flow

  12. Study of the giant multipole resonances, especially the isoscalar giant E2 resonance in 208Pb by inelastic electron scattering with medium and high energy resolution

    International Nuclear Information System (INIS)

    Kuehner, E.G.F.

    1982-01-01

    In the nucleus 208 Pb giant multipole resonances were looked for by inelastic electron scattering up to excitation energies of Esub(x) = 35 MeV. Twelve spectra were taken up at incident energies of Esub(o) = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. Basing on this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as a superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forwards angles a further weak excitation appears at Esub(x) approx.= 14.6 MeV which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is also observed in (α,α') scattering experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also Jsup(π) = 3 - character but has partly to be assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gels because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

  13. Study of the giant multipole resonances especially of the isoscalar giant E2 resonance in 208Pb by medium and high energy resolution inelastic electron scattering

    International Nuclear Information System (INIS)

    Kuehner, G.

    1982-01-01

    In the nucleus 208 Pb giant multipole resonances up to excitation energies of Esub(x) = 35 MeV were looked for by medium resolution inelastic electron scattering. Twelve spectra were taken up at incident energies of E 0 = 45-65 MeV under scattering angles from upsilon = 93 0 to 165 0 . The cross sections extracted from this were analyzed by means of DWBA calculations using RPA amplitudes from a model with separable residual interaction. On the base of this analysis for the first time it could be shown that the maximum in the electron scattering cross section at Esub(x) approx.= 14 MeV can be consistently described as superposition of the Jsup(π) = 1 - , ΔT = 1 with a Jsup(π) = 0 + , ΔT = 0 giant resonance. Furthermore the spectra under backward scattering angles indicate the existence of a magnetic excitation at Esub(x) approx.= 15 MeV which is interpreted as Jsup(π) = 3 + giant resonance. Besides under forward angles a further weak excitation at Esub(x) approx.= 14.6 MeV appears which is very well compatible with Jsup(π) = 2 + . At Esub(x) = 17.5 MeV a Jsup(π) = 3 - resonance was found which recently is observed also in (α, α') experiments and therefore gets a ΔT = 0 assignment. A further resonance at Esub(x) approx.= 21 MeV has also a Jsup(π) = 3 - character but has to be partly assigned to a Jsup(π) = 1 - , ΔT = 0 excitation. At Esub(x) = 23.8 MeV a Jsup(π) = 2 + excitation was found which gets because of model predictions a ΔT = 1 assignment. (orig./HSI) [de

  14. Overtones of isoscalar giant resonances studied in direct particle decay measurements

    NARCIS (Netherlands)

    Hunyadi, M; van den Berg, AM; Csatlos, M; Csige, L; Davids, B; Garg, U; Gulyas, J; Harakeh, MN; de Huu, MA; Krasznahorkay, A; Sohler, D; Wortche, HJ

    The isoscalar giant dipole resonance (ISGDR), which is the lowest-energy overtone mode of the isoscalar giant resonances, has been studied in some medium-heavy and heavy nuclei in coincidence measurements. The observation of the direct nucleon decay channels significantly helped to enhance giant

  15. Observation of the M1 giant resonance by resonance averaging in 106Pd

    International Nuclear Information System (INIS)

    Kopecky, J.

    1987-01-01

    An investigation of capture of 2 keV and 24 keV neutrons in a 105 Pd target resulted in resonance-averaged intensities of primary gamma rays with energies between 5.2 and 9.5 MeV. From these intensities the gamma ray strength functions have been evaluated for E1, M1 and E2 radiation and compared with predictions of the giant resonance theory. The inclusion of an energy dependent spreading width for the E1 giant resonance is necessary. The energy distribution of M1 reduced strength is consistent with an interpretation of a broad resonance around 8.8 MeV. E2 data agrees satisfactorily with the giant extrapolation. (orig.)

  16. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful ... for an MRI exam contains a metal called gadolinium . Gadolinium can be used in patients with iodine ...

  17. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... work? Unlike conventional x-ray examinations and computed tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, ... Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic Resonance Imaging (MRI) Safety Contrast Materials Children ...

  18. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses ... identify and accurately characterize diseases than other imaging methods. This detail makes MRI an invaluable tool in ...

  19. Magnetic resonance of low dimensional magnetic solids

    Energy Technology Data Exchange (ETDEWEB)

    Gatteschi, D.; Ferraro, F.; Sessoli, R. (Florence Univ. (Italy))

    1994-06-01

    The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs.

  20. Magnetic resonance of low dimensional magnetic solids

    International Nuclear Information System (INIS)

    Gatteschi, D.; Ferraro, F.; Sessoli, R.

    1994-01-01

    The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs

  1. Advances in magnetic resonance 12

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 12, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains six chapters and begins with a discussion of diffusion and self-diffusion measurements by nuclear magnetic resonance. This is followed by separate chapters on spin-lattice relaxation time in hydrogen isotope mixtures; the principles of optical detection of nuclear spin alignment and nuclear quadropole resonance; and the spin-1 behavior, including the relaxation of the quasi-invariants of the motion of a system of pairs of dipolar coupled spin-1/2 nu

  2. Magnetic resonance imaging methodology

    International Nuclear Information System (INIS)

    Moser, Ewald; Stadlbauer, Andreas; Windischberger, Christian; Quick, Harald H.; Ladd, Mark E.

    2009-01-01

    Magnetic resonance (MR) methods are non-invasive techniques to provide detailed, multi-parametric information on human anatomy, function and metabolism. Sensitivity, specificity, spatial and temporal resolution may, however, vary depending on hardware (e.g., field strength, gradient strength and speed) and software (optimised measurement protocols and parameters for the various techniques). Furthermore, multi-modality imaging may enhance specificity to better characterise complex disease patterns. Positron emission tomography (PET) is an interesting, largely complementary modality, which might be combined with MR. Despite obvious advantages, combining these rather different physical methods may also pose challenging problems. At this early stage, it seems that PET quality may be preserved in the magnetic field and, if an adequate detector material is used for the PET, MR sensitivity should not be significantly degraded. Again, this may vary for the different MR techniques, whereby functional and metabolic MR is more susceptible than standard anatomical imaging. Here we provide a short introduction to MR basics and MR techniques, also discussing advantages, artefacts and problems when MR hardware and PET detectors are combined. In addition to references for more detailed descriptions of MR fundamentals and applications, we provide an early outlook on this novel and exciting multi-modality approach to PET/MR. (orig.)

  3. Statistical decay of giant monopole resonance in 208Pb

    International Nuclear Information System (INIS)

    Dias, H.; Wolynec, E.

    1984-01-01

    The neutron spectrum from the decay of the monopole giant resonance in 208 Pb is calculated using the known energy levels of 207 Pb. The particle vibrator model is used to assign spins parities to the measured 207 Pb levels, where these were not avaliable from experiments. The results of the Hauser-Feshbach calculation is in excellent agreement with the experimental spectrum, showing that the observed fast neutrons can be completely explained assuming a statistical decay. (Author) [pt

  4. The width of the giant dipole resonance at finite temperature

    International Nuclear Information System (INIS)

    Mau, N.V.

    1992-01-01

    A method is proposed to evaluate the effect of the change of the Fermi sea on the width of the giant dipole resonance at finite temperature. In a schematic model it is found that, indeed, in 208 Pb the width increases very sharply up to about T=4 MeV but shows a much weaker variation for higher temperature. (author) 26 refs., 7 figs., 2 tabs

  5. Temperature dependence of spreading width of giant dipole resonance

    International Nuclear Information System (INIS)

    Storozhenko, A.N.; Vdovin, A.I.; Ventura, A.; Blokhin, A.I.

    2002-01-01

    The Quasiparticle-Phonon Nuclear Model extended to finite temperature within the framework of Thermo Field Dynamics is applied to calculate a temperature dependence of the spreading width Γ ↓ of a giant dipole resonance. Numerical calculations are made for 120 Sn and 208 Pb nuclei. It is found that Γ ↓ increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones, existing in the literature

  6. Quantized TDHF for isoscalar giant quadrupole resonances in spherical nuclei

    International Nuclear Information System (INIS)

    Drozdz, S.; Okolowicz, J.; Ploszajczak, M.; Caurier, E.

    1988-01-01

    The time-dependent Hartree-Fock theory supplemented with the regularity and single-valuedness quantization condition for the gauge invariant component of the wavefunction is applied to the description of the centroid energy and escape width of isoscalar giant quadrupole resonances in 16 O, 40 Ca and 110 Zr. Calculations are performed using the Skyrme SIII effective interaction. An important role of the finite oscillation amplitude in the mean-field dynamics is emphasized. (orig.)

  7. Direct vs statistical decay of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Hussein, M.S.

    1986-07-01

    A theoretical framework for the description of the decay of giant multipole resonances is developed. Besides the direct decay, both the pre-equilibrium and statistical (compound) decays are taken into account in a consistent way. It is shown that the statistical decay of the GR is not necessarily correctly described by the Hauser-Feshbach theory owing to the presence of a mixing parameter, which measures the degree of fragmentation. Applications are made to several cases. (Author) [pt

  8. Statistical decay of the E1 giant resonance

    International Nuclear Information System (INIS)

    Teruya, N.; Dias, H.; Wolynec, E.

    1987-10-01

    Available esperimental data on neutron decay spectra from the E1 giant resonances in 208 Pb and 209 Bi are compared with the predicted spectra for statistical decay. The calculations are performed using the Hauser-Feshbach formalism with the experimental levels of the residual nuclei. The particle-vibrator model is used to assign spins and parities to experimental levels when those are unknown and also to predict the levels where there is not enough experimental information. (author) [pt

  9. Optimization experiments on the study of giant resonance in nuclei

    International Nuclear Information System (INIS)

    Lyubarskij, G.Ya.; Savitskij, G.A.; Fartushnyj, V.A.; Khazhmuradov, M.A.; Levandovskij, S.P.

    1988-01-01

    Optimum choice of the target exposure to a beam in experiments on the study of giant resonances in nuclei is considered. Optimization is aimed at reducing mean square errors of defined formfactors. Four different optimization quality criteria - variances of four form factor experimental values are considered. Variances resulting form optimization are 1.5-2 times as less as variances in real experiment. The effect of experiment design optimization criterion on form factors determination errors is ascertained. 1 ref.; 3 tabs

  10. Theoretical Predictions of Giant Resonances in 94Mo

    Science.gov (United States)

    Golden, Matthew; Bonasera, Giacomo; Shlomo, Shalom

    2016-09-01

    We perform Hartree-Fock based Random Phase Approximation using thirty-three common Skyrme interactions found in the literature for 94Mo. We calculate the strength functions and the Centroid Energies of the Isoscalar Giant Resonances for all multipolarities L0, L1, L2, L3. We compare the calculated Centroid Energies with the experimental value; we also study the Centroid Energy and any correlation it may have with the Nuclear Matter properties of each interaction.

  11. Electron inelastic scattering by compound nuclei and giant multipole resonances

    International Nuclear Information System (INIS)

    Dzhavadov, A.V.; Mukhtarov, A.I.; Mirabutalybov, M.M.

    1980-01-01

    Multipole giant resonances in heavy nuclei have been investigated with the application of the Danos-Greiner dynamic collective theory to the Tassi model. The monopole giant resonance has been studied in 158 Gd, 166 Er, 184 W, 232 Th and 238 V nuclei at the incident electron energy E=200 MeV. Dependences of the form factor square of electron scattering by a 166 Er nucleus on the scattering angle obtained in the distorted-wave high-energy approximation (DWHEA) are presented. Giant dipole and quadrupole resonances in 60 Ni and 90 Zr nuclei have been studied. A comparison has been made of theoretical results obtained in the DWHEA for the dependence of the form factor square on the effective momentum transfer with the experimental data. The analysis of the obtained results led to the following conclusions. To draw a conclusion about the validity of one or another nuclear model and methods for calculating form factors, it is necessary to investigate, both theoretically and experimentally, electron scattering at great angles (THETA>=70 deg). To obtain a good agreement it is necessary to take account of the actual proton and neutron distributions in the ground state and their dynamic properties in an excited state [ru

  12. Random phase approximation: from Giant to Intra-doublet resonances

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    2004-01-01

    We discuss here the history and current achievements of one of the most powerful approaches of 20th century physics--the random phase approximation (RPA) that permits us to study collective or multiparticle effects in atoms, nuclei, molecules and clusters, as well as in quantum liquids. We concentrate on RPA application to studies of isolated atoms where it permits one to disclose the collective multielectron nature of so-called Giant resonances and predict a number of others, like Interference and Intra-doublet resonances. We present general theory as well as results of concrete calculations for a number of atoms

  13. Random phase approximation: from Giant to Intra-doublet resonances

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. E-mail: amusia@vms.huji.ac.il

    2004-06-01

    We discuss here the history and current achievements of one of the most powerful approaches of 20th century physics--the random phase approximation (RPA) that permits us to study collective or multiparticle effects in atoms, nuclei, molecules and clusters, as well as in quantum liquids. We concentrate on RPA application to studies of isolated atoms where it permits one to disclose the collective multielectron nature of so-called Giant resonances and predict a number of others, like Interference and Intra-doublet resonances. We present general theory as well as results of concrete calculations for a number of atoms.

  14. History of Giant Resonances and Quenching

    CERN Document Server

    Arima, A

    1999-01-01

    The history of nuclear magnetic moments and Gamow-Teller transitions is reviewed. The importance of configuration mixing and core polarization to explain the quenching phenomena is shown, and discussed in the context of the recent measurement of the Gamow-Teller strength in sup 9 sup 0 Nb. It is confirmed that the contribution of the DELTA-hole excitation to the quenching of spin matrix elements is small.

  15. Electroexcitation of giant multipole resonances in 208Pb

    International Nuclear Information System (INIS)

    Sasao, M.; Torizuka, Y.

    1977-01-01

    Electroexcitation of the nuclear continuum for 208 Pb at excitation energies up to 100 MeV has been measured at momentum transfers in the range from 0.45 to 1.2 fm -1 . Unfolding of the radiation tail was performed using a tail function which takes into account the multiple-photon emission effect. The spectra at these momentum transfers deviate significantly from the prediction of the Fermi-gas model but are consistent with the sum of the multipole strengths of the random-phase approximation; the excess cross section on the low excitation energy side indicates the excitation of multipole resonances. A series of 208 Pb spectra at low momentum transfers was expanded into E1, E2 (E0), E3, and higher multipole components using the q dependence of the Tassie model for isoscalar modes and the Goldhaber-Teller or Steinwedel-Jensen model for isovector modes. The giant dipole resonance thus obtained is consistent with that from photoreactions. Isoscalar and isovector giant quadrupole resonances are seen, respectively, at 11 and 22.5 MeV and an octupole resonance at 16 MeV. A monopole resonance is suggested at 13.5 MeV. The reduced 2 > 2 , B (E1), B (E2), and B (E3) consume most of the corresponding energy weighted sum rule if the q dependences of the Tassie and Goldhaber-Teller models are assumed. The results with these models are consistent with the random-phase approximation

  16. Low field magnetic resonance imaging

    Science.gov (United States)

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  17. Parallel magnetic resonance imaging

    International Nuclear Information System (INIS)

    Larkman, David J; Nunes, Rita G

    2007-01-01

    Parallel imaging has been the single biggest innovation in magnetic resonance imaging in the last decade. The use of multiple receiver coils to augment the time consuming Fourier encoding has reduced acquisition times significantly. This increase in speed comes at a time when other approaches to acquisition time reduction were reaching engineering and human limits. A brief summary of spatial encoding in MRI is followed by an introduction to the problem parallel imaging is designed to solve. There are a large number of parallel reconstruction algorithms; this article reviews a cross-section, SENSE, SMASH, g-SMASH and GRAPPA, selected to demonstrate the different approaches. Theoretical (the g-factor) and practical (coil design) limits to acquisition speed are reviewed. The practical implementation of parallel imaging is also discussed, in particular coil calibration. How to recognize potential failure modes and their associated artefacts are shown. Well-established applications including angiography, cardiac imaging and applications using echo planar imaging are reviewed and we discuss what makes a good application for parallel imaging. Finally, active research areas where parallel imaging is being used to improve data quality by repairing artefacted images are also reviewed. (invited topical review)

  18. Noncontrast Magnetic Resonance Lymphography.

    Science.gov (United States)

    Arrivé, Lionel; Derhy, Sarah; El Mouhadi, Sanaâ; Monnier-Cholley, Laurence; Menu, Yves; Becker, Corinne

    2016-01-01

    Different imaging techniques have been used for the investigation of the lymphatic channels and lymph glands. Noncontrast magnetic resonance (MR) lymphography has significant advantages in comparison with other imaging modalities. Noncontrast MR lymphography uses very heavily T2-weighted fast spin echo sequences which obtain a nearly complete signal loss in tissue background and specific display of lymphatic vessels with a long T2 relaxation time. The raw data can be processed with different algorithms such as maximum intensity projection algorithm to obtain an anatomic representation. Standard T2-weighted MR images easily demonstrate the location of edema. It appears as subcutaneous infiltration of soft tissue with a classical honeycomb pattern. True collection around the muscular area may be demonstrated in case of severe lymphedema. Lymph nodes may be normal in size, number, and signal intensity; in other cases, lymph nodes may be smaller in size or number of lymph nodes may be restricted. MR lymphography allows a classification of lymphedema in aplasia (no collecting vessels demonstrated); hypoplasia (a small number of lymphatic vessels), and numerical hyperplasia or hyperplasia (with an increased number of lymphatic vessels of greater and abnormal diameter). Noncontrast MR lymphography is a unique noninvasive imaging modality for the diagnosis of lymphedema. It can be used for positive diagnosis, differential diagnosis, and specific evaluation of lymphedema severity. It may also be used for follow-up evaluation after treatment. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  19. Magnetic resonance imaging. 1

    International Nuclear Information System (INIS)

    Wall, E.E. van der; Roos, A.A. de; Doornbos, J.; Dijkman, P.R.M. van; Matheijssen, N.A.A.; Laarse, A. van der; Krauss, X.H.; Blokland, J.A.k.; Manger Cats, V.; Voorthuisen, A.E. van; Bruschke, A.V.G.

    1991-01-01

    The cardiovascular applications of MRI in coronary artery disease have considerably increased in recent years. Although many applications overlap those of other more cost-effective techniques, such as echocardiography, radionuclide angiography, and CT, MRI offers unique features not shared by the conventional techniques. Technical advantages are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. This allows the accurate assessment of left ventricular mass and volume, the differentiation of infarcted tissue from normal myocardial tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. Also inducible myocardial ischemia using pharmacological stress (dipyramidole or dobutamine) may be assessed by magnetic resonance imaging. Future technical developments include real-time imaging and noninvasive visualization of the coronary arteries. These advantages will have a major impact on the application of MRI in coronary artery disease, potentially unsurpassed by other techniques and certainly justifying the expenses. Consequently, the clinical use of MRI for the detection of coronary artery disease largely depends on the progress of technical developments. (author). 134 refs.; 10 figs.; 2 tabs

  20. Advances in magnetic resonance 9

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 9 describes the magnetic resonance in split constants and dipolar relaxation. This book discusses the temperature-dependent splitting constants in the ESR spectra of organic free radicals; temperature-dependent splittings in ion pairs; and magnetic resonance induced by electrons. The electron impact excitation of atoms and molecules; intramolecular dipolar relaxation in multi-spin systems; and dipolar cross-correlation problem are also elaborated. This text likewise covers the NMR studies of molecules oriented in thermotropic liquid crystals and diffusion

  1. Advances in magnetic resonance 1

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 1, discusses developments in various areas of magnetic resonance. The subject matter ranges from original theoretical contributions through syntheses of points of view toward series of phenomena to critical and painstaking tabulations of experimental data. The book contains six chapters and begins with a discussion of the theory of relaxation processes. This is followed by separate chapters on the development of magnetic resonance techniques for studying rate processes in chemistry and the application of these techniques to various problems; the geometri

  2. Isotopic dependence of the giant quadrupole resonance in the stable even-mass molybdenum nuclei

    International Nuclear Information System (INIS)

    Moalem, A.; Gaillard, Y.; Bemolle, A.M.; Buenerd, M.; Chauvin, J.; Duhamel, G.; Lebrun, D.; Martin, P.; Perrin, G.; de Saintignon, P.

    1979-01-01

    Inelastic scattering of 110 MeV 3 He particles is used to probe the quadrupole strength in the even Mo isotopes. The peak position of the giant quadrupole resonance is found to decrease more rapidly than predicted by the A/sup -1/3/ law, a behavior very similar to that exhibited by the photonuclear giant dipole resonance. The width and strength of the giant quadrupole resonance are practically constant in 92 Mo through 100 Mo

  3. Giant resonance of electrical multipole from droplet model

    International Nuclear Information System (INIS)

    Tauhata, L.

    1984-01-01

    The formalism of the electrical multipole resonance developed from the Droplet nuclear model is presented. It combines the approaches of Goldhaber-Teller (GT) and Steinwedel-Jensen (SJ) and it shows the relative contribution of Coulomb, superficial and neutron excess energies. It also discusses the calculation of half-width. The model evaluates correctly the resonance energies as a function of nuclear mass and allows, through the Mixture Index, the prediction of the complementary participation of modes SJ and GT in the giant nuclear resonance. Values of the mixture index, for each multipolarity, reproduce well the form factors obtained from experiments of charged particle inelastic scattering. The formalism presented for the calculation of the half-width gives a macroscopic description of the friction mechanism. The establishment of the macroscopic structure of the Dissipation Function is used as a reference in the comparison of microscopic calculations. (Author) [pt

  4. Form factors and radiation widths of the giant multipole resonances

    International Nuclear Information System (INIS)

    Denisov, V.Yu.

    1990-01-01

    Simple analytic relations for the form factors of inelastic electron scattering in the Born approximation and radiation widths of the isovector and isoscalar giant multipole resonances are derived. The dynamic relationship between the volume and surface density vibrations were taken into account in this calculation. The form factors in the Born approximation were found to be in satisfactory agreement with experimental data in the region of small transferred momenta. The radiation widths of isoscalar multipole resonances increase when the number of nucleons increase as A 1/3 , and for isovector resonances this dependence has the form f(A)A 1/3 , where f(A) is a slowly increasing function of A. Radiation widths well fit the experimental data

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... are the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging ( ... brain) in routine clinical practice. top of page What are some common uses of the procedure? MR ...

  7. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... As the hydrogen atoms return to their usual alignment, they emit different amounts of energy that vary ... story about radiology? Share your patient story here Images × Image Gallery Radiologist prepping patient for magnetic resonance ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... As the hydrogen atoms return to their usual alignment, they emit different amounts of energy that vary ... story about radiology? Share your patient story here Images × Image Gallery Magnetic Resonance Imaging (MRI) procedure View ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

  10. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

  11. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... or thyroid problems. Any of these conditions may influence the decision on whether contrast material will be ... bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ...

  12. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... it is useful to bring that to the attention of the technologist or scheduler before the exam. ... patient for magnetic resonance imaging (MRI) exam. View full size with caption Pediatric Content Some imaging tests ...

  13. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... it is useful to bring that to the attention of the scheduler before the exam and bring ... Image Gallery Magnetic Resonance Imaging (MRI) procedure View full size with caption Pediatric Content Some imaging tests ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... MRI) exam. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, ...

  15. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... necessary in trauma situations. Although there is no reason to believe that magnetic resonance imaging harms the ...

  16. Magnetic resonance imaging the basics

    CERN Document Server

    Constantinides, Christakis

    2014-01-01

    Magnetic resonance imaging (MRI) is a rapidly developing field in basic applied science and clinical practice. Research efforts in this area have already been recognized with five Nobel prizes awarded to seven Nobel laureates in the past 70 years. Based on courses taught at The Johns Hopkins University, Magnetic Resonance Imaging: The Basics provides a solid introduction to this powerful technology. The book begins with a general description of the phenomenon of magnetic resonance and a brief summary of Fourier transformations in two dimensions. It examines the fundamental principles of physics for nuclear magnetic resonance (NMR) signal formation and image construction and provides a detailed explanation of the mathematical formulation of MRI. Numerous image quantitative indices are discussed, including (among others) signal, noise, signal-to-noise, contrast, and resolution. The second part of the book examines the hardware and electronics of an MRI scanner and the typical measurements and simulations of m...

  17. Magnetic Resonance Imaging. Chapter 15

    Energy Technology Data Exchange (ETDEWEB)

    Leach, M. O. [The Institute of Cancer Research and The Royal Marsden Hospital, London (United Kingdom)

    2014-09-15

    In Chapter 14, the principles of nuclear magnetic resonance were presented, along with an introduction to image forming processes. In this chapter, magnetic resonance imaging (MRI) will be reviewed, beginning with the hardware needed and its impact on image quality. The acquisition processes and image reconstruction will be discussed, as well as the artefacts that are possible, with discussion of the important area of safety and bioeffects completing the chapter.

  18. The nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Goyer, Ph.

    1997-01-01

    The spectroscopy of nuclear magnetic resonance constitutes a major analytical technique in biological and organic analysis. This technique appears now in the programme of preparatory classes and its teaching is developed in the second year of DEUG. The following article reviews on the nuclear magnetic resonance and on the possibilities it offers to bring to the fore the physico-chemical properties of molecules. (N.C.)

  19. Advances in magnetic resonance 2

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 2, features a mixture of experimental and theoretical contributions. The book contains four chapters and begins with an ambitious and general treatment of the problem of signal-to-noise ratio in magnetic resonance. This is followed by separate chapters on the interpretation of nuclear relaxation in fluids, with special reference to hydrogen; and various aspects of molecular theory of importance in NMR.

  20. Excitation and photon decay of giant resonances excited by intermediate energy heavy ions

    International Nuclear Information System (INIS)

    Bertrand, F.E.; Beene, J.R.

    1987-01-01

    Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the giant resonances. In particular, recent measurements have been made of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon 17 O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the 208 Pb isovector quadrupole resonance using its gamma decay are presented. 22 refs., 19 figs., 1 tab

  1. Nuclear magnetic resonance diagnostic apparatus

    International Nuclear Information System (INIS)

    Sugimoto, H.

    1985-01-01

    Nuclear magnetic resonance diagnostic apparatus including a coil for generating a gradient field in a plane perpendicular to a static magnetic field, means for controlling the operation of the coil to rotationally shift in angular steps the gradient direction of the gradient field at an angle pitch of some multiple of the unit index angle through a plurality of rotations to assume all the shift positions of the gradient direction, a rough image reconstructor for reconstructing a rough tomographic image on the basis of nuclear magnetic resonance signals acquired during a rotation of the second gradient magnetic field, a rough image display for depicting the rough tomographic image, a final image reconstructor for reconstructing a final tomographic image on the basis of all nuclear magnetic resonance signals corresponding to all of the expected rotation shift positions acquired during a plurality of rotations and a final image display for depicting the final tomographic image

  2. Giant Electric Field Control of Magnetism and Narrow Ferromagnetic Resonance Linewidth in FeCoSiB/Si/SiO2/PMN PT Multiferroic Heterostructures (Open Access Author’s Manuscript)

    Science.gov (United States)

    2016-06-06

    the widely used lead zirconate titanate ceramics which have a typical piezoelectric coefficient d31 of ~- 200pC/N, PMN-PT single crystals used in...substrate clamping effect, therefore, a relatively giant tunability can be obtained. However, the normally large roughness of piezoelectric layer...is the saturation magnetostriction constant, Y the Young’s modulus of the magnetic film, deff the effective piezoelectric coefficient, E

  3. Nuclear magnetic resonance and earth magnetic field

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Nuclear magnetic resonance concerns nuclei whose spin is different from 0. These nuclei exposed to a magnetic field is comparable to a peg top spinning around its axis while being moved by a precession movement called Larmor precession. This article presents an experiment whose aim is to reveal nuclear magnetism of nuclei by observing Larmor precession phenomena due to the earth magnetic field. The earth magnetic field being too weak, it is necessary to increase the magnetization of the sample during a polarization phase. First the sample is submitted to a magnetic field B perpendicular to the earth magnetic field B 0 , then B is cut off and the nuclei move back to their equilibrium position by executing a precession movement due to B 0 field. (A.C.)

  4. Giant Magnetoresistance: Basic Concepts, Microstructure, Magnetic Interactions and Applications.

    Science.gov (United States)

    Ennen, Inga; Kappe, Daniel; Rempel, Thomas; Glenske, Claudia; Hütten, Andreas

    2016-06-17

    The giant magnetoresistance (GMR) effect is a very basic phenomenon that occurs in magnetic materials ranging from nanoparticles over multilayered thin films to permanent magnets. In this contribution, we first focus on the links between effect characteristic and underlying microstructure. Thereafter, we discuss design criteria for GMR-sensor applications covering automotive, biosensors as well as nanoparticular sensors.

  5. Giant moving vortex mass in thick magnetic nanodots.

    Science.gov (United States)

    Guslienko, K Y; Kakazei, G N; Ding, J; Liu, X M; Adeyeye, A O

    2015-09-10

    Magnetic vortex is one of the simplest topologically non-trivial textures in condensed matter physics. It is the ground state of submicron magnetic elements (dots) of different shapes: cylindrical, square etc. So far, the vast majority of the vortex dynamics studies were focused on thin dots with thickness 5-50 nm and only uniform across the thickness vortex excitation modes were observed. Here we explore the fundamental vortex mode in relatively thick (50-100 nm) dots using broadband ferromagnetic resonance and show that dimensionality increase leads to qualitatively new excitation spectra. We demonstrate that the fundamental mode frequency cannot be explained without introducing a giant vortex mass, which is a result of the vortex distortion due to interaction with spin waves. The vortex mass depends on the system geometry and is non-local because of important role of the dipolar interaction. The mass is rather small for thin dots. However, its importance increases drastically with the dot thickness increasing.

  6. Magnetic Resonance Imaging

    Science.gov (United States)

    ... Permanent cosmetics or tattoos Dentures/teeth with magnetic keepers Other implants that involve magnets Medication patch (i. ... or longer. You’ll be told ahead of time just how long your scan is expected to ...

  7. Fission decay properties of nuclear giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Arruda Neto, J.D.T.; Hussein, M.S.; Carlson, B.V.

    1986-05-01

    The statistical fission decay properties of the giant dipole, quadrupole and monopole resonances in 236 U are investigated with the aid of the Hauser-Feshbach model. It is found, contrary to several recent claims, that the GQR fission decay probability is as large as that of the GDR, at energies higher than the fission barrier. At energies close to the f.b., the GQR fission probability is found to be appreciably larger than that of the GDR. The GMR fission probability follows closely that of the GQR. (Author) [pt

  8. Measurement of isovector giant quadrupole resonance in 40Ca

    International Nuclear Information System (INIS)

    Sims, D.A.; Thompson, M.N.; Rassool, R.; Adler, J.O.; Andersson, B.E.; Hansen, K.; Issaksson, L.; Nilsson, B.; Ruijter, H.; Schroeder, B.; Annand, J.R.M.; McGeorge, J.C.; Crawford, G.I.; Miller, G.J.

    1997-01-01

    The 40 Ca(γ,n) reaction was measured using tagged photons in the energy range 25-50 MeV. Neutrons were detected using two 9-element, liquid scintillator, neutron detectors placed at angles of 55 deg and 125 deg at flight path of 3.2 m. The absolute cross section was determined relative to that for D (γ,n)p, which was measured using a heavy water target. The forward/backward asymmetry in the 40 Ca (γ, n) cross section, resulting from E1/E2 interference has been used to locate and parametrize the isovector giant quadrupole resonance (IVQR). 6 refs., 2 figs

  9. The giant resonances in hot nuclei. Linear response calculations

    International Nuclear Information System (INIS)

    Braghin, F.L.; Vautherin, D.; Abada, A.

    1995-01-01

    The isovector response function of hot nuclear matter is calculated using various effective Skyrme interactions. For Skyrme forces with a small effective mass the strength distribution is found to be nearly independent of temperature, and shows little collective effects. In contrast effective forces with an effective mass close to unity produce at zero temperature sizeable collective effects which disappear at temperatures of a few MeV. The relevance of these results for the saturation of the multiplicity of photons emitted by the giant dipole resonance in hot nuclei observed in recent experiments beyond T = 3 MeV is discussed. (authors). 12 refs., 3 figs

  10. Noble gas magnetic resonator

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

  11. Magnetization tunneling in high-symmetry single-molecule magnets: Limitations of the giant spin approximation

    Science.gov (United States)

    Wilson, A.; Lawrence, J.; Yang, E.-C.; Nakano, M.; Hendrickson, D. N.; Hill, S.

    2006-10-01

    Electron paramagnetic resonance (EPR) studies of a Ni4 single-molecule magnet (SMM) yield the zero-field-splitting (ZFS) parameters D , B40 , and B44 , based on the giant spin approximation (GSA) with S=4 ; B44 is responsible for the magnetization tunneling in this SMM. Experiments on an isostructural Ni-doped Zn4 crystal establish the NiII ion ZFS parameters. The fourth-order ZFS parameters in the GSA arise from the interplay between the Heisenberg interaction Jŝ1•ŝ2 and the second-order single-ion anisotropy, giving rise to mixing of higher-lying S≠4 states into the S=4 state. Consequently, J directly influences the ZFS in the ground state, enabling its determination by EPR.

  12. Atomic many-body theory of giant resonances

    International Nuclear Information System (INIS)

    Kelly, H.P.; Altun, Z.

    1987-01-01

    In this paper the use of many-body perturbation theory (MBPT) to include effects of electron correlations is discussed. The various physical processes contributing to the broad photoionization cross sections of the rare gases are studied in terms of the relevant many-body diagrams. Use of the random phase approximation with exchange (RPAE) is discussed by Amusia and Cherepkov. Calculations using the relativistic RPAE are reviewed by Johnson. In addition, many-body perturbation theory (MBPT) is used to study resonances which are due to excitation of bound states degenerate with the continuum. Very interesting giant resonance structure can occur when an inner shell electron is excited into a vacant open-shell orbital of the same principal quantum number. A particular example which is studied is the neutral manganese atom 3p 6 3d 5 4s 2 ( 6 S), in which the spins of the five 3d electrons are aligned. A very large resonance occurs in the 3d and 4s cross sections due to 3p → 3d excitation near 51 eV, and calculations of this resonance by MBPT and RPAE are discussed. A second example of this type of resonance occurs in open-shell rare-earth atoms with configurations 4d 10 4f/sup n/5s 2 5p 6 s 2 . Calculations and experimental results will be discussed for the case of europium with a half-filled sub-shell 4f 7 . 71 references, 15 figures

  13. The Droplet model of the Giant Fipole Resonance

    International Nuclear Information System (INIS)

    Myers, W.D.; Kodama, T.; El-Jaick, L.J.; Hilf, E.R.

    1976-10-01

    The nuclear Giant Dipole Resonance (GDR) energies are calculated using a macroscopic hydronamical model with two new features. The motion is treated as a combination of the usual Goldhaber-Teller (GT) and Steinwedel-Jensen (SJ) modes, and the restoring forces are all calculated using the Droplet Model. The A dependence of the resonance energies is well reproduced without any adjustable parameters, and the measured magnitude of the energies serves to fix the value of the effective mass m* used in the theory. The GDR is found to consist mainly of a GT-type motion with the SJ-mode becoming more important for heavy nuclei. The width P of the GDR is also estimated on the basis of an expression for one-body damping [pt

  14. The isoscalar giant dipole resonance and nuclear incompressibility

    International Nuclear Information System (INIS)

    Garg, U.

    2000-01-01

    Complete text of publication follows. The current status of the experimental work on the ISOSCALAR giant dipole resonance (ISGDR) will be reviewed. ISGDR is an exotic mode of collective nuclear vibration and can be described as a hydrodynamical density oscillation in which the volume of the nucleus remains constant and the state can be visualized in the form of a compression wave-analogous to a sound wave-oscillating back and forth through the nucleus. [1] Convincing evidence for the ISGDR has now been obtained in inelastic α-scattering measurements at 200 MeV (IUCF) [2], 240 MeV (Texas A and M) [3] and 400 MeV (RCNP, Osaka) [4]. In all nuclei studied so far, the ISGDR strength is observed to be spread over a rather wide excitation-energy range (up to ∼ 15 MeV). The excitation energy of the ISGDR is related to the nuclear incompressibility, K ∞ . The ISGDR results so far point to a value for K ∞ that is ∼ 30-40% lower than the obtained from the energies of the other compressional mode, the giant monopole resonance. Results from recent theoretical attempts to reconcile this difference will be presented. This work has been supported in part by the U.S. National Science Foundation. (author)

  15. Structure and direct decay of Giant Monopole Resonances

    International Nuclear Information System (INIS)

    Avez, B.; Simenel, C.

    2013-01-01

    We study structure and direct decay of the Giant Monopole Resonance (GMR) at the Random Phase Approximation (RPA) level using the time-dependent energy density functional method in the linear response regime in a few doubly magic nuclei. A proper treatment of the continuum, through the use of large coordinate space, allows for a separation between the nucleus and its emitted nucleons. The microscopic structure of the GMR is investigated with the decomposition of the strength function into individual single-particle quantum numbers. A similar microscopic decomposition of the spectra of emitted nucleons by direct decay of the GMR is performed. In this harmonic picture of giant resonance, shifting every contribution by the initial single-particle energy allows to reconstruct the GMR strength function. The RPA residual interaction couples bound 1-particle 1-hole states to unbound ones, allowing for the total decay of the GMR. In this article, we then intend to get an understanding of the direct decay mechanism from coherent one-particle-one-hole superpositions, while neglecting more complex configurations. Time-dependent beyond mean-field approaches should be used, in the future, to extend this method. (orig.)

  16. Role of giant resonance excitation in heavy ion collisions

    International Nuclear Information System (INIS)

    Catara, F.; Chomaz, Ph.

    1987-01-01

    In this paper we discuss several aspects of heavy ion collisions involving collective vibrational modes. In our approach the relative motion is treated in a semiclassical approximation, while the intrinsic degrees of freedom are described microscopically within the RPA. The differences with respect to macroscopic models are analyzed in the appendix. First we present some results on the inelastic scattering cross section and we show that the structures observed experimentally can be explained in terms of multiple excitation of the Giant Quadrupole Resonance. After we calculate an adiabatic polarization potential describing the coupling to the collective vibrational modes and show that it produces a strong enhancement of the subbarrier fusion cross section. This enhancement is found to be enough to reproduce the experimental data for symmetric systems, while for asymmetric reactions the coupling to other degrees of freedom, like transfer, is needed. Finally we report some preliminary results on a dynamical calculation of the real and imaginary parts of the polarization potential. We show that at high incident energies (E/A > 20MeV) the role of the Giant Quadrupole Resonance becomes dominant

  17. Fourier transform nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Geick, R.

    1981-01-01

    This review starts with the basic principles of resonance phenomena in physical systems. Especially, the connection is shown between the properties of these systems and Fourier transforms. Next, we discuss the principles of nuclear magnetic resonance. Starting from the general properties of physical systems showing resonance phenomena and from the special properties of nuclear spin systems, the main part of this paper reviews pulse and Fourier methods in nuclear magnetic resonance. Among pulse methods, an introduction will be given to spin echoes, and, apart from the principle of Fourier transform nuclear magnetic resonance, an introduction to the technical problems of this method, e.g. resolution in the frequency domain, aliasing, phase and intensity errors, stationary state of the spin systems for repetitive measurements, proton decoupling, and application of Fourier methods to systems in a nonequilibrium state. The last section is devoted to special applications of Fourier methods and recent developments, e.g. measurement of relaxation times, solvent peak suppression, 'rapid scan'-method, methods for suppressing the effects of dipolar coupling in solids, two-dimensional Fourier transform nuclear magnetic resonance, and spin mapping or zeugmatography. (author)

  18. Magnetic resonance and porous materials

    International Nuclear Information System (INIS)

    McDonald, P.; Strange, J.

    1998-01-01

    Mention the words magnetic resonance to your medical advisor and he or she will immediately think of a multi-million pound scanner that peers deep into the brain. A chemist, on the other hand, will imagine a machine that costs several hundred thousand pounds and produces high-resolution spectra for chemical analysis. Food technologists will probably think of a bench-top instrument for determining moisture content, while an oil prospector will envisage a device that can be operated several kilometres down an oil well. To a physicist the term is more likely to conjure up a mental picture of nuclear spins precessing in a magnetic field. These examples illustrate the diverse aspects of a phenomenon discovered by physicists over 50 years ago. Electron spin resonance was first discovered by Russian scientists, and nuclear magnetic resonance was discovered in the US shortly afterwards by Ed Purcell at Harvard University and Felix Bloch at Stanford University. Today, nuclear magnetic resonance (NMR) is the most widely used technique. Modern NMR machines are making it possible to probe microstructure and molecular movement in materials as diverse as polymers, cements, rocks, soil and foods. NMR allows the distribution of different components in a material to be determined with a resolution approaching 1μm, although the signal can be sensitive to even smaller lengthscales. In this article the authors describe how physicists are still developing magnetic resonance to exploit a range of new applications. (UK)

  19. GHz nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  20. Principles of magnetic resonance imaging

    International Nuclear Information System (INIS)

    Mlynarik, V.; Tkac, I.; Srbecky, M.

    1995-01-01

    The aim of this review is to describe and explain the basic principles of magnetic resonance imaging. The first part of the text is devoted to the phenomenon of magnetic resonance (the interaction of RF magnetic field with the set of magnetic moments in the homogeneous magnetic field) and to relaxation processes. Then, the creation of MR image is described (slice selection, phase and frequency encoding of spatial information). The basic and the most frequently used techniques are explained (spin echo, gradient echo). The way the repetition and echo times influence the image quality and contrast (T1 or T2 weighing) is described. The part with the technical description of the MR equipment is included in the review. The MR imagination examination are compared with X-ray computer tomography technique

  1. The temperature dependence of giant resonances in high-excited nucleus

    International Nuclear Information System (INIS)

    Li Ming; Song Hongqiu

    1991-01-01

    The Hartree-Fock equation and the linear response theory in finite temperature are used to calculate the positions and transition strenghths of the giant resonances of high-excited nucleus Pb 208 . The result shows a downward shift and a broadening of the giant resonance energies as temperatrue increases

  2. Reaction theory for analysis of nuclear giant resonances production and decay processes

    International Nuclear Information System (INIS)

    Foglia, G.A.

    1991-01-01

    The existence of mixing parameters connected to the different decay forms of the giant resonances was theoretically justified, and their energy dependence determined as well using a reaction theory which treats in a consistent manner the giant multipolar resonances formation and their different decay modes. (L.C.J.A.)

  3. Bifurcation magnetic resonance in films magnetized along hard magnetization axis

    Energy Technology Data Exchange (ETDEWEB)

    Vasilevskaya, Tatiana M., E-mail: t_vasilevs@mail.ru [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation); Sementsov, Dmitriy I.; Shutyi, Anatoliy M. [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation)

    2012-09-15

    We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: Black-Right-Pointing-Pointer An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. Black-Right-Pointing-Pointer Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. Black-Right-Pointing-Pointer Both regular and chaotic precession modes are realized within bifurcation resonance range. Black-Right-Pointing-Pointer Appearance of dynamic bistability is typical for bifurcation resonance.

  4. Bifurcation magnetic resonance in films magnetized along hard magnetization axis

    International Nuclear Information System (INIS)

    Vasilevskaya, Tatiana M.; Sementsov, Dmitriy I.; Shutyi, Anatoliy M.

    2012-01-01

    We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: ► An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. ► Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. ► Both regular and chaotic precession modes are realized within bifurcation resonance range. ► Appearance of dynamic bistability is typical for bifurcation resonance.

  5. Recommendations concerning magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    1986-01-01

    In medicine the technique of nuclear magnetic resonance (NMR) is applied in the form of in vivo nuclear magnetic resonance spectroscopy (MRS). In vivo MRS can be carried out non-invasively. The committee of the Dutch Health Council briefly discusses the qualities and potentialities of the nuclei that will probably be used in future clinical spectroscopy: 31 P, 13 C, 1 H (and possibly 19 F and 23 Na). The committee discusses several possibilities of combining imaging and spectroscopy. The imaging of nuclei other than protons is also possible with MRS. Potential applications are considered in oncology, cardiology, neurology and hepatology. (Auth.)

  6. Migraine and magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Younis, Samaira; Hougaard, Anders; Vestergaard, Mark B.

    2017-01-01

    Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation in the meth......Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation...

  7. Magnetic fields in starspots on late-type giants

    International Nuclear Information System (INIS)

    Jahn, K.

    1985-01-01

    Computations of models of magnetic starspots on cool active giants show that the value of the magnetic intensity in spots is generally of the order of one kilogauss, although in larger spots the field can be as weak as a few hundred gauss. It is also argued, that spots on giants qualitatively differ from those on late-type dwarfs, since they cannot be too large. The largest individual spots can cover at most about one percent of a stellar hemisphere. This is in a very good agreement with earlier suggestions based on observations of spotted giants. The assumption that spots are the regions of the strongest magnetic field allows to discuss recent attempts of detection of the magnetic field on late-type giants. Polarimetric measurements most probably cannot be successful, due to a small field strength and a complex topology of the field. It is shown that even if a whole surface was covered by spots with relatively strong field, the resulting not longitudinal field would be as weak as a few gauss. Also methods independent of polarimetric measurements, based on the analysis of Zeeman broadening, generally are not sensitive enough to detect the magnetic field on giants, even in spots. λ And is discussed as an example. The comparison of models of spots computed for that stars with photometric observations suggests, that a dark region on λ And consists of hundreds of small spots (each of them smaller than about 0.1% of the hemisphere), in which the magnetic intensity cannot exceed about 900 gauss, and most probably is even smaller. 23 refs., 4 figs., 4 tabs. (author)

  8. Outward Migration of Giant Planets in Orbital Resonance

    Science.gov (United States)

    D'Angelo, G.; Marzari, F.

    2013-05-01

    A pair of giant planets interacting with a gaseous disk may be subject to convergent orbital migration and become locked into a mean motion resonance. If the orbits are close enough, the tidal gaps produced by the planets in the disk may overlap. This represents a necessary condition to activate the outward migration of the pair. However, a number of other conditions must also be realized in order for this mechanism to operate. We have studied how disk properties, such as turbulence viscosity, temperature, surface density gradient, mass, and age, may affect the outcome of the outward migration process. We have also investigated the implications on this mechanism of the planets' gas accretion. If the pair resembles Jupiter and Saturn, the 3:2 orbital resonance may drive them outward until they reach stalling radii for migration, which are within ~10 AU of the star for disks representative of the early proto-solar nebula. However, planet post-formation conditions in the disk indicate that such planets become typically locked in the 1:2 orbital resonance, which does not lead to outward migration. Planet growth via gas accretion tends to alter the planets' mass-ratio and/or the disk accretion rate toward the star, reducing or inhibiting outward migration. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

  9. Charge-exchange giant resonances as probes of nuclear structure

    International Nuclear Information System (INIS)

    Blomgren, J.

    2001-09-01

    Giant resonances populated in charge-exchange reactions can reveal detailed information about nuclear structure properties, in spite of their apparent featurelessness. The (p,n) and (n,p) reactions - as well as their analog reactions - proceed via the same nuclear matrix element as beta decay. Thereby, they are useful for probing electroweak properties in nuclei, especially for those not accessible to beta decay. The nuclear physics aspects of double beta decay might be investigated in double charge-exchange reactions. detailed nuclear structure information, such as the presence of ground-state correlations, can be revealed via identification of 'first-forbidden' transitions. In addition, astrophysics aspects and halo properties of nuclei have been investigated in charge exchange. Finally, these experiments have questioned our knowledge of the absolute strength of the strong interaction

  10. The giant quadrupole resonance in highly excited rotating nuclei

    International Nuclear Information System (INIS)

    Civitarese, O.; Furui, S.; Ploszajczak, M.; Faessler, A.

    1983-01-01

    The giant quadrupole resonance in highly excited, fast rotating nuclei is studied as a function of both the nuclear temperature and the nuclear angular momentum. The photo-absorption cross sections for quadrupole radiation in 156 Dy, 160 Er and 164 Er are evaluated within the linear response theory. The strength functions of the γ-ray spectrum obtained from the decay of highly excited nuclear states by deexcitation of the isoscalar quadrupole mode show a fine structure, which depends on the temperature T, the angular momentum I and the deformation of the nucleus β. The splitting of the modes associated with the signature-conserving and signature-changing components of the quadrupole field is discussed. (orig.)

  11. Phase-space exploration in nuclear giant resonance decay

    International Nuclear Information System (INIS)

    Drozdz, S.; Nishizaki, S.; Wambach, J.; Speth, J.

    1995-01-01

    The rate of phase-space exploration in the decay of isovector and isoscalar giant quadrupole resonances in 40 Ca is analyzed. The study is based on the time dependence of the survival probability and of the spectrum of generalized entropies evaluated in the space of one-particle--one-hole (1p-1h) and 2p-2h states. Three different cases for the level distribution of 2p-2h background states, corresponding to (a) high degeneracy, (b) classically regular motion, and (c) classically chaotic motion, are studied. In the latter case the isovector excitation evolves almost statistically while the isoscalar excitation remains largely localized, even though it penetrates the whole available phase space

  12. The giant resonance and the shape of hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bracco, A; Camera, F; Million, B; Pignanelli, M [Milan Univ. (Italy). Ist. di Fisica; Gaardhoje, J J; Maj, A; Atac, A [Niels Bohr Inst., Copenhagen (Denmark)

    1992-08-01

    The gamma decay of the giant dipole resonance is a sensitive tool for investigating how nuclear shape changes with spin and excitation energy, but the information is coded in a subtle way, inasmuch as the shape and orientation of nuclei at finite temperature display large fluctuations. At the time of the conference, the three systems {sup 109-110}Sn, {sup 161-162}Yb and {sup 165-167}Er had recently been studied on the HECTOR spectrometer. The Sn nuclei are spherical in their ground states, and are expected to become oblate under the stress of rotation. The Yb and Er nuclei are prolate, and are expected to become first spherical, then oblate. While the patterns of the measured angular anisotropies are consistent with this general picture, many questions still remain open. 3 refs., 1 tab., 3 figs.

  13. Decay of the giant monopole resonance in heavy nuclei

    International Nuclear Information System (INIS)

    Brandenburg, S.

    1985-01-01

    In this thesis an experimental study of the properties of the giant monopole resonance (GMR) in nuclei is described. The main subject is the study of the neutron decay of the GMR in 208 Pb, and the fission decay of the GMR in 238 U. Furthermore the strength distribution and decay properties of the monopole strength in 24 Mg and 40 Ca were studied. The strength distribution of the isoscalar monopole (and also of the isoscalar dipole) strength as obtained from the angular distribution of the excited strength at small scattering angles are discussed. For the excitation of the GMR inelastic scattering at very small scattering angles, including 0 0 , of 120 MeV α-particles was employed. The experimental technique for performing this type of measurements at the KVI was developed in the course of this study and is the subject of a separate chapter. (Auth.)

  14. Evanescent Waves Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order...

  15. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

  17. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Magnetic Resonance Imaging Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ... links: For the convenience of our users, RadiologyInfo .org provides links to relevant websites. RadiologyInfo.org , ACR ...

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

  19. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ... Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain ...

  1. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... of which shows a thin slice of the body. The images can then be studied from different angles by ... about radiology? Share your patient story here Images ... Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ...

  2. Inelastic electron scattering, fine structure of M1 giant resonances and Gamow-Teller states

    International Nuclear Information System (INIS)

    Richter, A.

    1983-01-01

    Recent progress in obtaining detailed fine structure distributions of magnetic giant resonances in nuclei using high resolution inelastic electron scattering at low energy is discussed. Specific examples chosen are the medium heavy nuclei 40 42 44 48 Ca in which M1 excitations are due to neutron spin-flip transitions and the N=28 isotones 50 Ti, 52 Cr and 54 Fe where in addition also proton excitations contribute to the measured M1 strength. It is found that the M1 strength is very fragmented and considerably quenched in comparison to predictions of shell model calculations in a model space that includes up to 2p-2h excitations. Finally, the old problem of M1 strength in 208 Pb is revisited and the results of a form factor measurement of a recently discovered low lying Jsup(π)=1 + state by nuclear resonance fluorescence are presented. (Auth.)

  3. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Brain KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Brain What's in this article? What ...

  4. Advances in magnetic and optical resonance

    CERN Document Server

    Warren, Warren S

    1997-01-01

    Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.

  5. Magnetic resonance for wireless power transfer

    OpenAIRE

    Hui, SYR

    2016-01-01

    Magnetic resonance has been a cornerstone of nonradiative wireless power transfer (WPT) since the late 19th century. However, some researchers have the misconception that magnetic resonance for WPT was developed recently. This article traces some early work of Tesla and other researchers related to the use of magnetic resonance in WPT. Included are some examples of magnetic resonance-based WPT projects conducted by researchers in the biomedical and power electronics communities over the last ...

  6. Concerning the generation of geomagnetic giant pulsations by drift-bounce resonance ring current instabilities

    Directory of Open Access Journals (Sweden)

    K.-H. Glassmeier

    Full Text Available Giant pulsations are nearly monochromatic ULF-pulsations of the Earth's magnetic field with periods of about 100 s and amplitudes of up to 40 nT. For one such event ground-magnetic observations as well as simultaneous GEOS-2 magnetic and electric field data and proton flux measurements made in the geostationary orbit have been analysed. The observations of the electromagnetic field indicate the excitation of an odd-mode type fundamental field line oscillation. A clear correlation between variations of the proton flux in the energy range 30-90 keV with the giant pulsation event observed at the ground is found. Furthermore, the proton phase space density exhibits a bump-on-the-tail signature at about 60 keV. Assuming a drift-bounce resonance instability as a possible generation mechanism, the azimuthal wave number of the pulsation wave field may be determined using a generalized resonance condition. The value determined in this way, 
    m
    = - 21 ± 4, is in accord with the value m = - 27 ± 6 determined from ground-magnetic measurements. A more detailed examination of the observed ring current plasma distribution function f shows that odd-mode type eigenoscillations are expected for the case ∂f / ∂W > 0, much as observed. This result is different from previous theoretical studies as we not only consider local gradients of the distribution function in real space, but also in velocity space. It is therefore concluded that the observed giant pulsation is the result of a drift-bounce resonance instability of the ring current plasma coupling to an odd-mode fundamental standing wave. The generation of the bump-on-the-tail distribution causing ∂f / ∂W > 0 can be explained due to velocity dispersion of protons injected into the ring current. Both this velocity dispersion and the necessary substorm activity causing the injection of protons into the nightside magnetosphere are observed

  7. Concerning the generation of geomagnetic giant pulsations by drift-bounce resonance ring current instabilities

    Directory of Open Access Journals (Sweden)

    K.-H. Glassmeier

    1999-03-01

    Full Text Available Giant pulsations are nearly monochromatic ULF-pulsations of the Earth's magnetic field with periods of about 100 s and amplitudes of up to 40 nT. For one such event ground-magnetic observations as well as simultaneous GEOS-2 magnetic and electric field data and proton flux measurements made in the geostationary orbit have been analysed. The observations of the electromagnetic field indicate the excitation of an odd-mode type fundamental field line oscillation. A clear correlation between variations of the proton flux in the energy range 30-90 keV with the giant pulsation event observed at the ground is found. Furthermore, the proton phase space density exhibits a bump-on-the-tail signature at about 60 keV. Assuming a drift-bounce resonance instability as a possible generation mechanism, the azimuthal wave number of the pulsation wave field may be determined using a generalized resonance condition. The value determined in this way,  m = - 21 ± 4, is in accord with the value m = - 27 ± 6 determined from ground-magnetic measurements. A more detailed examination of the observed ring current plasma distribution function f shows that odd-mode type eigenoscillations are expected for the case ∂f / ∂W > 0, much as observed. This result is different from previous theoretical studies as we not only consider local gradients of the distribution function in real space, but also in velocity space. It is therefore concluded that the observed giant pulsation is the result of a drift-bounce resonance instability of the ring current plasma coupling to an odd-mode fundamental standing wave. The generation of the bump-on-the-tail distribution causing ∂f / ∂W > 0 can be explained due to velocity dispersion of protons injected into the ring current. Both this velocity dispersion and the necessary substorm activity causing the injection of protons into the nightside magnetosphere are observed.Key words. Magnetospheric physics (energetic particles , trapped

  8. Strength function for the giant isovector monopole resonance

    International Nuclear Information System (INIS)

    MacDonald, W.M.; Birse, M.C.

    1984-01-01

    The theory of the strength function for giant resonances is extended to exhibit the explicit energy dependence of the width and shift functions for the giant isovector monopole. An integral sum rule on the width GAMMA/sub M/(E) relates its normalization to the second moment M 2 of the strength function and leads to a relation GAMMA/sub M/(E/sub M/)GAMMA/sub s//4 = M 2 between M 2 and the width at the maximum, which involves the width GAMMA/sub s/ of the distribution in energy of the spreading matrix elements. An estimate of GAMMA/sub M/(E/sub M/)approx. =8 MeV based on the absorptive part of the optical potential together with random-phase approximation calculations of M 2 leads to the result GAMMA/sub s//2approx. =2hω, supporting the intermediate coupling model of Lane, Thomas, and Wigner. Using the sum rule expressions of Lane and Mekjian to evaluate the Coulomb matrix element M/sub A/M between an isobaric analog state and its corresponding isovector monopole, we test this strength function for the isovector monopole by calculating the spreading widths for the ground state analogs of nuclei from 38 Cl to 208 Pb. The good agreement with the systematic dependence upon mass number and isospin resolves the long-standing discrepancy between the estimate GAMMA/sub M/(E/sub M/)approx.8--10 MeV and the value GAMMA/sub M/(E/sub A/)< or =2 MeV needed to account for the spreading widths of the isobaric analog state

  9. Magnetic resonance tomography in syringomyelia

    International Nuclear Information System (INIS)

    Koehler, D.; Treisch, J.; Hertel, G.; Schoerner, W.; Fiegler, W.; Staedtisches Rudolf-Virchow Krankenhaus, Berlin

    1985-01-01

    Thirteen patients with a clinical diagnosis of syringomyelia were examined by nuclear tomography (0.35 T magnet) in the spin-echo mode. In all thirteen patients, the T1 images (Se 400/35) showed a longitudinal cavity with a signal intensity of CSF. The shape and extent of the syrinx could be adequately demonstrated in 12 of the 13 examinations. Downward displacement of the cerebellar tonsils was seen in eight cases. The examination took between half and one hour. Advantages of magnetic resonance tomography (nuclear tomography) include the absence of artifacts, images in the line of the lesion and its non-invasiveness. (orig.) [de

  10. Limits to magnetic resonance microscopy

    International Nuclear Information System (INIS)

    Glover, Paul; Mansfield, Peter

    2002-01-01

    The last quarter of the twentieth century saw the development of magnetic resonance imaging (MRI) grow from a laboratory demonstration to a multi-billion dollar worldwide industry. There is a clinical body scanner in almost every hospital of the developed nations. The field of magnetic resonance microscopy (MRM), after mostly being abandoned by researchers in the first decade of MRI, has become an established branch of the science. This paper reviews the development of MRM over the last decade with an emphasis on the current state of the art. The fundamental principles of imaging and signal detection are examined to determine the physical principles which limit the available resolution. The limits are discussed with reference to liquid, solid and gas phase microscopy. In each area, the novel approaches employed by researchers to push back the limits of resolution are discussed. Although the limits to resolution are well known, the developments and applications of MRM have not reached their limit. (author)

  11. Magnetic resonance and its applications

    CERN Document Server

    Chizhik, Vladimir I; Donets, Alexey V; Frolov, Vyacheslav V; Komolkin, Andrei V; Shelyapina, Marina G

    2014-01-01

    The book provides a basic understanding of the underlying theory, fundamentals and applications of magnetic resonance The book implies a few levels of the consideration (from simple to complex) of phenomena, that can be useful for different groups of readers The introductory chapter provides the necessary underpinning knowledge for newcomers to the methods The exposition of theoretical materials goes from initial to final formulas through detailed intermediate expressions.

  12. Photoionization of lanthanum and its ions in the region of the 'giant' resonance

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    1989-01-01

    The photoionization cross sections of outer and intermediate shells including 4d of La and its ions are calculated in the region of the 'giant' resonance. The prominent effects of both intershell correlational effects and rearrangement are demonstrated. (orig.)

  13. Inelastic scattering of 9Be of 27 MeV/A to giant resonances

    International Nuclear Information System (INIS)

    Lebrun, D.; Buenerd, M.; Bini, M.; Harvey, B.G.; Legrain, R.; Mahoney, J.; Symons, T.J.M.; Van Bibber, K.

    1980-07-01

    Inelastic scattering spectra have been measured with 245 MeV incident energy 9 Be ions, on 208 Pb target. They show large excitation of the 208 Pb giant quadrupole resonance. DWBA calculations are reported and compared with the data

  14. Transverse magnetization and giant magnetoimpedance in amorphous ribbons

    International Nuclear Information System (INIS)

    Orue, I.; Garcia-Arribas, A.; Saad, A.; Cos, D. de; Barandiaran, J.M.

    2005-01-01

    In the classical approach giant magnetoimpedance (GMI) is driven by the transverse permeability of the sample, as excited by the current flowing through it. Transverse permeability is usually taken as a constant, while detailed magnetization processes are important for the interpretation of GMI data. In most cases the transverse permeability (or magnetization) is only guessed by looking at the longitudinal magnetization curve and direct determinations of such parameter are scarce in the literature. In this work we report on the operation of a simple setup which provides the transverse magnetization of amorphous ribbons as a function of the current intensity flowing through it, by means of the magnetooptical kerr effect (MOKE). The system has been tested on low magnetostriction amorphous ribbons of very soft character with both longitudinal and transverse anisotropy. The transverse magnetization as a function of both the current and a DC longitudinal field applied, was compared with magneto impedance measurements

  15. (p,n) and (n,p) reactions as probes of isovector giant monopole resonances

    International Nuclear Information System (INIS)

    Auerbach, N.; Bowman, J.D.; Franey, M.A.; Love, W.G.

    1983-01-01

    Nucleon charge exchange reactions are explored as prospective probes of isovector giant monopole resonances. Using charge exchange transition densities based on random-phase approximation sum rules, distorted wave impulse approximation calculations are made for the (p,n) and (n,p) reactions exciting the isovector giant monopole resonances in several nuclei at bombarding energies of 120 and 800 MeV. Based on our calculations, the charge exchange reactions at 800 MeV appear more promising

  16. Statistical contribution in the giant multipolar resonance decay in hevay nuclei

    International Nuclear Information System (INIS)

    Teruya, N.

    1986-01-01

    Statistical calculations are made for the decay in the electric monopole giant resonance in 208 Pb and electric dipole giant resonance in 209 Bi, using the Hauser-Feshbach formalism. Calculations are done using the experimental energy levels of the corresponding residual nuclei. The particle-vibrator model is used for those experimental levels without spin and parity determination. The influence of different parametrizations of the optical potential in the statistical calculation result is also studied. (L.C.) [pt

  17. Influence of complex particle emission on properties of giant dipole resonance of hot nuclei

    International Nuclear Information System (INIS)

    Wen Wanxin; Jin Genming

    2003-01-01

    The possible reasons for the discrepancy between calculation results based on the statistical evaporation model and experimental data of giant dipole resonance of very hot nuclei are discussed. Both of simulations with the standard CASCADE code and the code coupling complex particle emission are carried out. It is shown that the complex particle emission affects the properties of giant dipole resonance of very hot nuclei

  18. Spectroscopic factors of the alpha decay of isoscalar giant resonances

    International Nuclear Information System (INIS)

    Smirnov, Yu.F.; Chuvil'skij, Yu.M.

    1983-01-01

    A system which enables to connect Ssub(α) spectroscopic factors (SF) for α-decay of the isoscalar giant resonance (GR) states E0 and E2 with SF values for ground and low lying nucleus states has been developed. This method permits to consider initial nucleus GR decay with a transition to the residual nucleus-GR. It is necessary to know only SF for GR decay to the daughter nucleus ground state with the emission of an excited cluster in the common case. The above method is based on properties of infinitesimal operators of Sp(2, R), Sp(6, R) groups and uses SU(3)-symmetry of wave functions of initial nucleus, cluster and residual nucleus, Values of ratios of α-particle SF are presented for 8 Be, HH2C, 16 O, 20 Ne, 24 Mg, 28 Si, 40 Ca, 44 Ti nuclei and Ssub(α) transitions to GR states of residual nucleus for 16 O, 20 Ne and 40 Ca nuclei. Noticeable Ssub(α) values for virtual α-decay of an initial nucleus ground state to residual nucleus GR poins out that α-particle knock out processes may be also accompanied by the final nucleus GR excitation

  19. Giant transversal particle diffusion in a longitudinal magnetic ratchet.

    Science.gov (United States)

    Tierno, Pietro; Reimann, Peter; Johansen, Tom H; Sagués, Francesc

    2010-12-03

    We study the transversal motion of paramagnetic particles on a uniaxial garnet film, exhibiting a longitudinal ratchet effect in the presence of an oscillating magnetic field. Without the field, the thermal diffusion coefficient obtained by video microscopy is D(0) ≈ 3 × 10(-4)  μm2/s. With the field, the transversal diffusion exhibits a giant enhancement by almost four decades and a pronounced maximum as a function of the driving frequency. We explain the experimental findings with a theoretical interpretation in terms of random disorder effects within the magnetic film.

  20. Giant quadrupole resonance in 12C, 24Mg, and 27Al observed via deuteron inelastic scattering

    International Nuclear Information System (INIS)

    Chang, C.C.; Didelez, J.P.; Kwiatowski, K.; Wo, J.R.

    1977-06-01

    Giant quadrupole resonance in 12 C, 24 Mg, and 27 Al was studied using 70 MeV deuteron beam. The results clearly show, in all three targets, resonance-like structures peaked at E/sub x/ approximately 63A/sup -1/3/ MeV, with a width of about 10 MeV. The experimental angular distributions for these resonances agree well with the l = 2 DWBA prediction. For 12 C, a binary splitting was observed, and for 24 Mg, there are indications of finer structure in the main giant quadrupole resonance region

  1. Comparison between magnetic resonance findings and conventional techniques (ultrasonography and mammography) in breast disease

    International Nuclear Information System (INIS)

    Martin, J.L.; Garofono, J.M.; Berquet, A.; Fernandez, F.J.; Fuentes, P.; Alvarez de Cienfuegos, E.

    1996-01-01

    Although mammography is indisputably the best diagnostic method for detecting breast abnormalities, there are other techniques, such as ultrasonography and magnetic resonance, which are increasingly widely employed as additional indispensable aids. The present work compares mammography, ultrasound and magnetic resonance images of normal breast and of the major pathologies that can be observed in breast, including sclerosing adenosis, giant fibroadenoma, multifocal carcinoma, fibrocystic breast disease, infiltrating duct carcinoma, colloid carcinoma, radical scar, abscess and breast prosthesis. (Author) 10 refs

  2. The nuclear magnetic resonance well logging

    International Nuclear Information System (INIS)

    Zhang Yumin; Shen Huitang

    2003-01-01

    In this paper, the characteristic of the nuclear magnetic resonance logging is described at first. Then its development and its principle is presented. Compared with the nuclear magnetic resonance spectrometer, the magnet techniques is the first question that we must solve in the manufacture of the NMR well logging

  3. Isoscalar giant resonances and Landau parameters with density-dependent effective interactions

    International Nuclear Information System (INIS)

    Kohno, Michio; Ando, Kazuhiko

    1979-01-01

    Discussion is given on the relations between the Landau parameters and the isoscalar giant (quadrupole- and monopole-) resonance energies by using general density-dependent interactions. In the limit of infinite nuclear matter, the isoscalar giant quadrupole energy is shown to depend not only on the effective mass but also on the Landau parameter F 2 . Collective energies of the isoscalar giant resonances are calculated for 16 O and 40 Ca with four different effective interactions, G-0, B1, SII and SV, by using the scaling- and constrained Hartree-Fock-methods. It is shown that the dependence of the collective energies on the effective interactions is essentially determined by the Landau parameters. The G-0 force is found to be most successful in reproducing the giant resonance energies. Validity of the RPA-moment theorems is examined for the case of local density-dependent interactions. (author)

  4. Magnetic bistability of isolated giant-spin centers in a diamagnetic crystalline matrix.

    Science.gov (United States)

    Vergnani, Luca; Barra, Anne-Laure; Neugebauer, Petr; Rodriguez-Douton, Maria Jesus; Sessoli, Roberta; Sorace, Lorenzo; Wernsdorfer, Wolfgang; Cornia, Andrea

    2012-03-12

    Polynuclear single-molecule magnets (SMMs) were diluted in a diamagnetic crystal lattice to afford arrays of independent and iso-oriented magnetic units. Crystalline solid solutions of an Fe(4) SMM and its Ga(4) analogue were prepared with no metal scrambling for Fe(4) molar fractions x down to 0.01. According to high-frequency EPR and magnetic measurements, the guest SMM species have the same total spin (S=5), anisotropy, and high-temperature spin dynamics found in the pure Fe(4) phase. However, suppression of intermolecular magnetic interactions affects magnetic relaxation at low temperature (40 mK), where quantum tunneling (QT) of the magnetization dominates. When a magnetic field is applied along the easy magnetic axis, both pure and diluted (x=0.01) phases display pronounced steps at evenly spaced field values in their hysteresis loops due to resonant QT. The pure Fe(4) phase exhibits additional steps which are firmly ascribed to two-molecule QT transitions. Studies on the field-dependent relaxation rate showed that the zero-field resonance sharpens by a factor of five and shifts from about 8 mT to exactly zero field on dilution, in agreement with the calculated variation of dipolar interactions. The tunneling efficiency also changes significantly as a function of Fe(4) concentration: the zero-field resonance is significantly enhanced on dilution, while tunneling at ±0.45 T becomes less efficient. These changes were rationalized on the basis of a dipolar shuffling mechanism and transverse dipolar fields, whose effect was analyzed by using a multispin model. Our findings directly prove the impact of intermolecular magnetic couplings on SMM behavior and disclose the magnetic response of truly isolated giant spins in a diamagnetic crystalline environment. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Magnetic resonance imaging at Rikshospitalet

    International Nuclear Information System (INIS)

    Smith, H.J.

    1990-01-01

    During the first 18 months of operations of the nuclear magnetic resonance (NMR) unit at Rikshospitalet, 1453 NMR examinations have been performed on 1431 patients. 64% of the time has been devoted to examinations of the central nervous system and spine in children and adults, 9% of the time has been used on non-neuroradiology pediatric patients, while the rest of the time has been spent equally on ear, nose and throat, thoracic (including cardiac) and abdominal examinations in adult patients. The indications for doing NMR at Rikshospitalet are listed and discussed, and it is concluded that NMR has proved to be useful at several conditions in most organ systems. 15 refs

  6. Magnetic resonance imaging in psychiatry

    International Nuclear Information System (INIS)

    Mann, K.

    1993-01-01

    Diagnosis and research in psychiatry are increasingly availing themselves of magnetic resonance imaging (MRI). In comparison to computed tomography (CT), this offers the combined benefits of no exposure to radiation, high resolution, artefact-free display of structures near bone, and a sharp contrast between the grey and white brain matter, with freedom to select the section. With the exception of very anxious patients, MRI will gradually replace CT scans for a wide range of differential diagnostic investigations. Its superiority in systematic studies of psychiatric patients with discrete cerebral parenchyma lesions is already considered proven. This is illustrated on the basis of research into schizophrenia and alcoholism. (orig.) [de

  7. Advances in magnetic resonance 3

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 3, describes a number of important developments which are finding increasing application by chemists. The book contains five chapters and begins with a discussion of how the properties of random molecular rotations reflect themselves in NMR and how they show up, often differently, in other kinds of experiments. This is followed by separate chapters on the Kubo method, showing its equivalence to the Redfield approach in the cases of most general interest; the current state of dynamic nuclear polarization measurements in solutions and what they tell us abou

  8. Resonant and nonresonant magnetic scattering (invited)

    International Nuclear Information System (INIS)

    McWhan, D.B.; Hastings, J.B.; Kao, C.; Siddons, D.P.

    1992-01-01

    The tunability and the polarization of synchrotron radiation open up new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and they fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin-polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation

  9. Tunable Magnetic Resonance in Microwave Spintronics Devices

    Science.gov (United States)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  10. Magnetic resonance imaging of Parkinsonism

    International Nuclear Information System (INIS)

    Mukai, Eiichiro; Makino, Naoki; Fujishiro, Kenichiro.

    1989-01-01

    We have analyzed magnetic resonance images in 33 patients; 18 patients with Parkinson's disease, 1 patient with diurnally fluctuating progressive dystonia, 1 patient with pure akinesia, 6 patients with multiple system atrophy, 1 patient with flunarizine induced parkinsonism, and 4 patients with unclassified parkinsonism. The MR images were obtained using a 1.5-T GE MR System. A spin-echo pulse sequence was used with a TE of 30 msec and 80 msec and a TR of 2000 msec. No signal abnormalities were seen in any patient with Parkinson's disease but 3 showed slightly decreased signal intensity of the putamen on T2-weighted sequences. Patients with diurnally fluctuating progressive dystonia and pure akinesia evidensed no abnormal findings. All six patients with multiple system atrophy demonstrated decreased signal intensity of the putamen, particularly along their lateral and posterior portions, and an enlarged substantia nigra. Atrophy of the pons and cerebellum was detected in all cases with multiple system atrophy. One case of flunarizine induced parkinsonism showed slightly decreased signal intensity of the putamen. Four cases of unclassified parkinsonism showed decreased signal in the putamen on T2-weighted sequences. Magnetic resonance imaging has the potential to become a useful diagnostic tool in the management of parkinsonism. (author)

  11. Magnetic resonance imaging of Parkinsonism

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, Eiichiro [National Hospital of Nagoya (Japan); Makino, Naoki; Fujishiro, Kenichiro

    1989-06-01

    We have analyzed magnetic resonance images in 33 patients; 18 patients with Parkinson's disease, 1 patient with diurnally fluctuating progressive dystonia, 1 patient with pure akinesia, 6 patients with multiple system atrophy, 1 patient with flunarizine induced parkinsonism, and 4 patients with unclassified parkinsonism. The MR images were obtained using a 1.5-T GE MR System. A spin-echo pulse sequence was used with a TE of 30 msec and 80 msec and a TR of 2000 msec. No signal abnormalities were seen in any patient with Parkinson's disease but 3 showed slightly decreased signal intensity of the putamen on T2-weighted sequences. Patients with diurnally fluctuating progressive dystonia and pure akinesia evidensed no abnormal findings. All six patients with multiple system atrophy demonstrated decreased signal intensity of the putamen, particularly along their lateral and posterior portions, and an enlarged substantia nigra. Atrophy of the pons and cerebellum was detected in all cases with multiple system atrophy. One case of flunarizine induced parkinsonism showed slightly decreased signal intensity of the putamen. Four cases of unclassified parkinsonism showed decreased signal in the putamen on T2-weighted sequences. Magnetic resonance imaging has the potential to become a useful diagnostic tool in the management of parkinsonism. (author).

  12. Migraine and magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Younis, Samaira; Hougaard, Anders; Vestergaard, Mark B.

    2017-01-01

    Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation in the meth......Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation...... in the methodology and quality of the MRS migraine studies over time, some results were consistent and reproducible. 31P-MRS studies suggested reduced availability of neuronal energy and implied a mitochondrial dysfunction in the migraine brain. 1H-MRS studies reported interictal abnormalities in the excitatory...... and inhibitory neurotransmitters, glutamate and g-aminobutyric acid (GABA), suggesting persistent altered excitability in migraine patients. N-Acetylaspartate levels were decreased in migraine, probably due to a mitochondrial dysfunction and abnormal energy metabolism. The reported abnormalities may increase...

  13. Magnetic resonance imaging of chemistry.

    Science.gov (United States)

    Britton, Melanie M

    2010-11-01

    Magnetic resonance imaging (MRI) has long been recognized as one of the most important tools in medical diagnosis and research. However, MRI is also well placed to image chemical reactions and processes, determine the concentration of chemical species, and look at how chemistry couples with environmental factors, such as flow and heterogeneous media. This tutorial review will explain how magnetic resonance imaging works, reviewing its application in chemistry and its ability to directly visualise chemical processes. It will give information on what resolution and contrast are possible, and what chemical and physical parameters can be measured. It will provide examples of the use of MRI to study chemical systems, its application in chemical engineering and the identification of contrast agents for non-clinical applications. A number of studies are presented including investigation of chemical conversion and selectivity in fixed-bed reactors, temperature probes for catalyst pellets, ion mobility during tablet dissolution, solvent dynamics and ion transport in Nafion polymers and the formation of chemical waves and patterns.

  14. Very low field magnetic resonance imaging

    International Nuclear Information System (INIS)

    Herreros, Quentin

    2013-01-01

    The aim of this thesis is to perform Magnetic Resonance Imaging at very low field (from 1 mT to 10 mT). A new kind of sensor called 'mixed sensor' has been used to achieve a good detectivity at low frequencies. Combining a superconducting loop and a giant magnetoresistance, those detectors have a competitive equivalent field noise compared to existing devices (Tuned coils, SQUIDs and Atomic Magnetometers). They have been combined with flux transformers to increase the coupling between the sample and the sensor. A complete study has been performed to adapt it to mixed sensors and then maximize the gain. This set has been incorporated in an existing small MRI device to test its robustness in real conditions. In parallel, several MRI sequences (GE, SE, FLASH, EPI,...) have been integrated and adapted to very low field requirements. They have been used to perform in-vivo three dimensional imaging and relaxometry studies on well known products to test their reliability. Finally, a larger setup adapted for full-head imaging has been designed and built to perform images on a larger working volume. (author) [fr

  15. Giant Cu 2p Resonances in CuO Valence-Band Photoemission

    NARCIS (Netherlands)

    Tjeng, L.H.; Chen, C.T.; Ghijsen, J.; Rudolf, P.; Sette, F.

    1991-01-01

    We report the observation of a giant resonance in the Cu 2p resonant-photoemission spectra of CuO. The study allows the unambiguous identification of the local Cu 3d8 configuration in the valence-band photoemission spectrum, providing conclusive evidence for the charge-transfer nature of the

  16. Giant Magnetic Field Enhancement in Hybridized MIM Structures

    KAUST Repository

    Alrasheed, Salma

    2017-10-23

    We propose numerically an approach to narrow the plasmon linewidth and enhance the magnetic near field intensity at a magnetic hot spot in a hybridized metal-insulatormetal (MIM) structure. First we insert in part of the dielectric layer of the MIM, at its center, another dielectric material of a high refractive index (HRI). This results in an increase in the magnetic near field enhancement of the magnetic plasmon (MP) resonance by 82% compared with the MIM without the HRI material. We then couple this enhanced MP resonance to a propagating surface plasmon polariton (SPP) to achieve a further enhancement of 438%. The strong coupling between the MP and the SPP is demonstrated by the large anti-crossing in the reflection spectra. The resulting maximum magnetic field enhancement at the gap is ~ |H / Hi|² = 3555.

  17. Advances in mechanical detection of magnetic resonance

    International Nuclear Information System (INIS)

    Kuehn, Seppe; Hickman, Steven A.; Marohn, John A.

    2008-01-01

    The invention and initial demonstration of magnetic resonance force microscopy (MRFM) in the early 1990s launched a renaissance of mechanical approaches to detecting magnetic resonance. This article reviews progress made in MRFM in the last decade, including the demonstration of scanned probe detection of magnetic resonance (electron spin resonance, ferromagnetic resonance, and nuclear magnetic resonance) and the mechanical detection of electron spin resonance from a single spin. Force and force-gradient approaches to mechanical detection are reviewed and recent related work using attonewton sensitivity cantilevers to probe minute fluctuating electric fields near surfaces is discussed. Given recent progress, pushing MRFM to single proton sensitivity remains an exciting possibility. We will survey some practical and fundamental issues that must be resolved to meet this challenge.

  18. Magnetic resonance imaging: hazard, risk and safety

    International Nuclear Information System (INIS)

    Narayan, Pradeep; Suri, S.; Singh, P.

    2001-01-01

    The hazard and risk associated with magnetic resonance imaging is a matter of concern. In 1982, the Food and Drug Administration (FDA), USA issued guidelines to Hospital's Investigational Review Board (IRBs) in 'Guidelines for Evaluating Electromagnetic Exposure Risks for Trials of Clinical Nuclear Magnetic Resonance (NMR)'. In 1997, the Berufsgenossenschaft (BG), professional association for precision engineering and electronics of Germany, in their preliminary proposal for safety limits extended their concerns on static magnetic field. Owing to both time varying and static magnetic fields applied in Magnetic Resonance Imaging (MRI) this became of immediate concern to user community to assess the potential hazard and risk associated with the NMR system

  19. Magnetic resonance imaging of Parkinsonism

    International Nuclear Information System (INIS)

    Nakamura, Yusaku; Takahashi, Mitsuo; Kitaguchi, Masataka; Akaneya, Yukio; Mitui, Yoshiyuki; Tanaka, Hisashi

    1991-01-01

    We studied eighteen patients affected by Parkinsonism with symptoms of tremor, bradykinesia, or rigidity using magnetic resonance imaging (MRI). Patients ranged in age from 34 to 80 years (mean 62.8±11.6 years), and the duration of their disease had been 3.8±3.2 years. MRI examinations were performed with Shimazu and Siemens superconducting magnets, operating at 0.5 and 1.5 T magnetic fields, respectively. Both T 1 - and T 2 -weighted spin echo (SE) pulse sequences were used. In eight patients (44.4%), MRI demonstrated bilateral multiple lacunar infarction of the basal ganglia. The most common abnormality identified was multiple, bilateral lacunar infarcts in the lateral portion of the putamen. The average size of the lacunar infarction of the putamen was less than half that of the entire putamen. Patients with multiple lacunar infarction were significantly older than the other patients and had lower Yahr's scores. The clinical symptoms of patients with bilateral multiple lacunar infarction of the basal ganglia were compatible with the diagnosis of arteriosclerotic Parkinsonism of akinetic rigid type. It has been suggested that multiple lacunar infarction of the basal ganglia may have led to Parkinsonism in these patients. (author)

  20. Nuclear magnetic resonance imaging method

    International Nuclear Information System (INIS)

    Johnson, G.; MacDonald, J.; Hutchison, S.; Eastwood, L.M.; Redpath, T.W.T.; Mallard, J.R.

    1984-01-01

    A method of deriving three dimensional image information from an object using nuclear magnetic resonance signals comprises subjecting the object to a continuous, static magnetic field and carrying out the following set of sequential steps: 1) exciting nuclear spins in a selected volume (90deg pulse); 2) applying non-aligned first, second and third gradients of the magnetic field; 3) causing the spins to rephase periodically by reversal of the first gradient to produce spin echoes, and applying pulses of the second gradient prior to every read-out of an echo signal from the object, to differently encode the spin in the second gradient direction for each read-out signal. The above steps 1-3 are then successively repeated with different values of gradient of the third gradient, there being a recovery interval between the repetition of successive sets of steps. Alternate echoes only are read out, the other echoes being time-reversed and ignored for convenience. The resulting signals are appropriately sampled, set out in an array and subjected to three dimensional Fourier transformation. (author)

  1. Magnetic fields in giant planet formation and protoplanetary discs

    Science.gov (United States)

    Keith, Sarah Louise

    2015-12-01

    Protoplanetary discs channel accretion onto their host star. How this is achieved is critical to the growth of giant planets which capture their massive gaseous atmosphere from the surrounding flow. Theoretical studies find that an embedded magnetic field could power accretion by hydromagnetic turbulence or torques from a large-scale field. This thesis presents a study of the inuence of magnetic fields in three key aspects of this process: circumplanetary disc accretion, gas flow across gaps in protoplanetary discs, and magnetic-braking in accretion discs. The first study examines the conditions needed for self-consistent accretion driven by magnetic fields or gravitational instability. Models of these discs typically rely on hydromagnetic turbulence as the source of effective viscosity. However, magnetically coupled,accreting regions may be so limited that the disc may not support sufficient inflow. An improved Shakura-Sunyaev ? disc is used to calculate the ionisation fraction and strength of non-ideal effects. Steady magnetically-driven accretion is limited to the thermally ionised, inner disc so that accretion in the remainder of the disc is time-dependent. The second study addresses magnetic flux transport in an accretion gap evacuated by a giant planet. Assuming the field is passively drawn along with the gas, the hydrodynamical simulation of Tanigawa, Ohtsuki & Machida (2012) is used for an a posteriori analysis of the gap field structure. This is used to post-calculate magnetohydrodynamical quantities. This assumption is self-consistent as magnetic forces are found to be weak, and good magnetic coupling ensures the field is frozen into the gas. Hall drift dominates across much of the gap, with the potential to facilitate turbulence and modify the toroidal field according to the global field orientation. The third study considers the structure and stability of magnetically-braked accretion discs. Strong evidence for MRI dead-zones has renewed interest in

  2. Dipole and quadrupole magnetic resonances in nuclei of Ni isotopes

    International Nuclear Information System (INIS)

    Goncharova, N.G.; Mishchenko, G.M.; Ehramzhyan, R.A.

    1982-01-01

    Basing on a microscopic approach to the nuclear shell model, magnetic resonances following the electron excitation of the 58 Ni and 60 Ni nuclei are considered. 0h/2π#betta# and 2h/2π#betta#-transitions are taken into accoun for the M1-excitations. For the M2-states, transitions to the next shell are considered only. For the magnetic excitations the form factors and electron-excitation cross sections are calculated, and the effect of the lower 2 1+ , 2 2+ , 3 - , 4 + phonon excitations on the position and structure of the M1- and M2-resonances is traced. +he energies and mean equilibrium deformations are presented for the phonons taken into account. The structure and position of the main magnetic resonance maxima, in difference with the giant dipole resonance in photoabsorption, have proven to be weakly dependent on the isotope choice. For the M1-resonance this effect is related with the fact that the lower excitation states, located in the energy range E 60 Ni and 58 Ni, respectively. A strongly collectivized state, acquiring a notable strength of the M-1 transitions, is located at approximately 32 MeV. The form factor for this level attains the maximum at q=160-190 MeV/c

  3. Collisional damping of giant monopole and quadrupole resonances

    International Nuclear Information System (INIS)

    Yildirim, S.; Gokalp, A.; Yilmaz, O.; Ayik, S.

    2001-01-01

    Collisional damping widths of giant monopole and quadrupole excitations for 120 Sn and 208 Pb at zero and finite temperatures are calculated within Thomas-Fermi approximation by employing the microscopic in-medium cross-sections of Li and Machleidt and the phenomenological Skyrme and Gogny forces, and are compared with each other. The results for the collisional widths of giant monopole and quadrupole vibrations at zero temperature as a function of the mass number show that the collisional damping of giant monopole vibrations accounts for about 30 - 40% of the observed widths at zero temperature, while for giant quadrupole vibrations it accounts for only 20 - 30% of the observed widths at zero temperature. (orig.)

  4. Instantons and magnetization tunneling: Beyond the giant-spin approximation

    International Nuclear Information System (INIS)

    Florez, J.M.; Vargas, P.; Nunez, Alvaro S.

    2009-01-01

    In this work we show that commonly neglected fluctuations of the net total spin of a molecular nanomagnet strongly modified its tunneling properties and provide a scenario to explain some discrepancies between theory and experiment. Starting off from an effective spin Hamiltonian, we study the quantum tunneling of the magnetization of molecular nanomagnets in the regime where the giant-spin approximation is breaking down. This study is done using an instanton description of the tunneling path. The instanton is calculated considering its coupling to quantum fluctuations.

  5. Transition metal nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Pregosin, P.S.

    1991-01-01

    Transition metal NMR spectroscopy has progressed enormously in recent years. New methods, and specifically solid-state methods and new pulse sequences, have allowed access to data from nuclei with relatively low receptivities with the result that chemists have begun to consider old and new problems, previously unapproachable. Moreover, theory, computational science in particular, now permits the calculation of not just 13 C, 15 N and other light nuclei chemical shifts, but heavy main-group element and transition metals as well. These two points, combined with increasing access to high field pulsed spectrometer has produced a wealth of new data on the NMR transition metals. A new series of articles concerned with measuring, understanding and using the nuclear magnetic resonance spectra of the metals of Group 3-12 is presented. (author)

  6. Gaucher's disease: Magnetic resonance findings

    International Nuclear Information System (INIS)

    Roca, M.; Gomez-Pereda, R.; Blasco, A.; Ros, L.

    1996-01-01

    The objective is to assess the role of magnetic resonance (MR) in determining the initial extension of Gaucher's disease and its complications. A retrospective study of eight patients diagnosed as having Gaucher's disease was carried out using MR. The study focused on pelvis, hip, femur, spine, liver parenchyma and splenic parenchyma. Infiltration of the cancellous portion of the vertebral bodies was observed in all but one of the patients. Three patients presented small hemangiomas in dorsal and lumbar vertebral bodies. Pelvic bone involvement was homogeneous in four cases and spotty in two, while the pelvic marrow was normal in the two patients with no vertebral infiltration. A vascular necrosis of the femoral head was detected in two cases. MR is very useful in determining the initial extension, in the early diagnosis of complications and in managing the posttreatment marrow response to assess the therapeutic efficacy. 16 refs

  7. Fetal abdominal magnetic resonance imaging

    International Nuclear Information System (INIS)

    Brugger, Peter C.; Prayer, Daniela

    2006-01-01

    This review deals with the in vivo magnetic resonance imaging (MRI) appearance of the human fetal abdomen. Imaging findings are correlated with current knowledge of human fetal anatomy and physiology, which are crucial to understand and interpret fetal abdominal MRI scans. As fetal MRI covers a period of more than 20 weeks, which is characterized not only by organ growth, but also by changes and maturation of organ function, a different MR appearance of the fetal abdomen results. This not only applies to the fetal intestines, but also to the fetal liver, spleen, and adrenal glands. Choosing the appropriate sequences, various aspects of age-related and organ-specific function can be visualized with fetal MRI, as these are mirrored by changes in signal intensities. Knowledge of normal development is essential to delineate normal from pathological findings in the respective developmental stages

  8. Fetal abdominal magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University of Vienna, Waehringerstrasse 13, 1090 Vienna (Austria)]. E-mail: peter.brugger@meduniwien.ac.at; Prayer, Daniela [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria)

    2006-02-15

    This review deals with the in vivo magnetic resonance imaging (MRI) appearance of the human fetal abdomen. Imaging findings are correlated with current knowledge of human fetal anatomy and physiology, which are crucial to understand and interpret fetal abdominal MRI scans. As fetal MRI covers a period of more than 20 weeks, which is characterized not only by organ growth, but also by changes and maturation of organ function, a different MR appearance of the fetal abdomen results. This not only applies to the fetal intestines, but also to the fetal liver, spleen, and adrenal glands. Choosing the appropriate sequences, various aspects of age-related and organ-specific function can be visualized with fetal MRI, as these are mirrored by changes in signal intensities. Knowledge of normal development is essential to delineate normal from pathological findings in the respective developmental stages.

  9. Magnetic resonance imaging in neuroradiology

    International Nuclear Information System (INIS)

    Voigt, K.; Lotx, J.W.

    1990-01-01

    Magnetic resonance imaging (MRI) is now accepted as an effective method of investigating a wide range of disorders, especially of the brain and spine. A short introduction on image contrast in MRI is given and the advantages and disadvantages for the different diseases of the brain is discussed. Excellent soft-tissue contrast, multiplanar imaging capabilities and lack of ionising radiation are conspicuous advantages, and it is now established as the investigation of choice in a large number of clinical conditions, especially when the central nervous system is involved. However, it remains only one of a series of imaging modalities. A confident provisional clinical diagnosis is essential for establishing an imaging protocol and the intention should always be to reach a definitive diagnosis in the least invasive and most cost-effective way. 7 figs., 19 refs

  10. Magnetic resonance imaging of the prostate

    DEFF Research Database (Denmark)

    Iversen, P; Kjaer, L; Thomsen, C

    1988-01-01

    Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate....

  11. Magnetic resonance imaging of the prostate

    DEFF Research Database (Denmark)

    Iversen, P; Kjaer, L; Thomsen, C

    1987-01-01

    Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate....

  12. Single voxel magnetic resonance spectroscopy in distinguishing ...

    African Journals Online (AJOL)

    Objective: Assess diagnostic utility of combined magnetic resonance imaging and magnetic resonance spectroscopy (MRI, MRS) in differentiating focal neoplastic lesions from focal non- neoplastic (infective or degenerative) brain lesions. Design: Descriptive, analytical - prospective study. Setting: The Aga Khan University ...

  13. Magnetic resonance imaging of radiation optic neuropathy

    International Nuclear Information System (INIS)

    Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S.

    1990-01-01

    Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence

  14. Magnetic resonance: discovery, investigations, and applications

    International Nuclear Information System (INIS)

    Kessenikh, Aleksandr V

    2009-01-01

    The history of the development of the theoretical ideas and experimental methods of magnetic resonance, as well as the applications of these methods in modern natural science, technology, and medicine, are outlined, with allowance for the contribution of Russian researchers. An assessment of some promising trends of studies and applications of magnetic resonance is given. (from the history of physics)

  15. Contrast agents in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Karadjian, V.

    1987-01-01

    The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes [fr

  16. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  17. Thermal and rotational effect on giant dipole resonances in rotating nuclei at high temperature

    International Nuclear Information System (INIS)

    Sugawara-Tanabe, Kazuko; Tanabe, Kosai.

    1986-01-01

    Microscopic calculations are carried out for the giant dipole resonances excited on the thermal high spin states in 162 Er and 166 Er based on the thermal linear response theory with realistic forces and large single-particle space. The dynamical strength function is compared with the experimental γ-ray absorption cross section. The general trend that the resonance energy decreases and the resonance width increases with increasing angular momentum and temperature is well reproduced by the calculations. (author)

  18. Magnetic resonance imaging of hypophysis

    International Nuclear Information System (INIS)

    Malla Huesh, I. V.

    2016-01-01

    Hypothalamic-pituitary diseases represent with wide variety of symptoms in regard with changes in the endocrine function. Magnetic resonance imaging has a crucial role in detecting the morphologic appearance in physiologic conditions, malformative diseases and acquired pathologies. The MR-imaging is established as the method of choice in assessing the changes in the hypothalamic-pituitary axis. The pituitary gland is a complex structure with an important role in the homeostasis of the organism even though it is so small? It is surrounded by bony structures, vessels, nerves and the brain parenchyma. It consists of three parts - anterior called - adenohypophysis, posterior - neurohypophysis and pituitary stalk. The anterior part comprises about 75% of the gland. Computed tomography (CT) has a limited role in detecting the pituitary gland. It is mainly used in cases of elevated intracranial pressure due to suspected apoplexy. The gland's small size, relation to other structures and its soft tissue characteristic make it an accessible region of interest for detecting with MR-imaging. The lack of ionizing energy and the technical advances in the MR-methods are responsible for the creating images with better spatial resolution and signal to noise ratio. The examination is carried out on a standard protocol. It is important that thin slices are executed in sagittal and coronal planes. Performing a sequence, regarding the brain parenchyma is essential, since many malformations of the pituitary gland are associated with other congenital conditions. The examination starts with a T1W sequence to assess the normal anatomic condition of the gland. The intensity of the adenohypophysis is compared to the one in the pons. It is hypointense, whereas the neurohypophysis is hyperintense, due to the lipid neurosecretory granules transported along the hypothalamic-pituitary axis. T2W-images in coronal plane are used to evaluate the hypothalamus, pituitary stalk, optic chiasm, olfactory

  19. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: mvmfonte@uol.com.br; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Radiologia; Reed, Umbertina Conti [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Rosemberg, Sergio [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Dept. de Patologia

    2008-11-15

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  20. Medulloblastoma: correlation among findings of conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Fonte, Mariana Vieira de Melo da; Otaduy, Maria Concepcion Garcia; Lucato, Leandro Tavares; Reed, Umbertina Conti; Leite, Claudia da Costa; Costa, Maria Olivia Rodrigues; Amaral, Raquel Portugal Guimaraes; Reed, Umbertina Conti; Rosemberg, Sergio

    2008-01-01

    To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T 1-weighted images and intermediate/hyperintense on T 2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Na a / Cr ratio (83.3%) and increased Co/Cr (100%) and ml/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors. (author)

  1. MAGNETIC ENERGY BUILDUP FOR RELATIVISTIC MAGNETAR GIANT FLARES

    International Nuclear Information System (INIS)

    Yu Cong

    2011-01-01

    Motivated by coronal mass ejection studies, we construct general relativistic models of a magnetar magnetosphere endowed with strong magnetic fields. The equilibrium states of the stationary, axisymmetric magnetic fields in the magnetar magnetosphere are obtained as solutions of the Grad-Shafranov equation in a Schwarzschild spacetime. To understand the magnetic energy buildup in the magnetar magnetosphere, a generalized magnetic virial theorem in the Schwarzschild metric is newly derived. We carefully address the question whether the magnetar magnetospheric magnetic field can build up sufficient magnetic energy to account for the work required to open up the magnetic field during magnetar giant flares. We point out the importance of the Aly-Sturrock constraint, which has been widely studied in solar corona mass ejections, as a reference state in understanding magnetar energy storage processes. We examine how the magnetic field can possess enough energy to overcome the Aly-Sturrock energy constraint and open up. In particular, general relativistic (GR) effects on the Aly-Sturrock energy constraint in the Schwarzschild spacetime are carefully investigated. It is found that, for magnetar outbursts, the Aly-Sturrock constraint is more stringent, i.e., the Aly-Sturrock energy threshold is enhanced due to the GR effects. In addition, neutron stars with greater mass have a higher Aly-Sturrock energy threshold and are more difficult to erupt. This indicates that magnetars are probably not neutron stars with extreme mass. For a typical neutron star with mass of 1-2 M sun , we further explore the cross-field current effects, caused by the mass loading, on the possibility of stored magnetic field energy exceeding the Aly-Sturrock threshold.

  2. Multidimensionally encoded magnetic resonance imaging.

    Science.gov (United States)

    Lin, Fa-Hsuan

    2013-07-01

    Magnetic resonance imaging (MRI) typically achieves spatial encoding by measuring the projection of a q-dimensional object over q-dimensional spatial bases created by linear spatial encoding magnetic fields (SEMs). Recently, imaging strategies using nonlinear SEMs have demonstrated potential advantages for reconstructing images with higher spatiotemporal resolution and reducing peripheral nerve stimulation. In practice, nonlinear SEMs and linear SEMs can be used jointly to further improve the image reconstruction performance. Here, we propose the multidimensionally encoded (MDE) MRI to map a q-dimensional object onto a p-dimensional encoding space where p > q. MDE MRI is a theoretical framework linking imaging strategies using linear and nonlinear SEMs. Using a system of eight surface SEM coils with an eight-channel radiofrequency coil array, we demonstrate the five-dimensional MDE MRI for a two-dimensional object as a further generalization of PatLoc imaging and O-space imaging. We also present a method of optimizing spatial bases in MDE MRI. Results show that MDE MRI with a higher dimensional encoding space can reconstruct images more efficiently and with a smaller reconstruction error when the k-space sampling distribution and the number of samples are controlled. Copyright © 2012 Wiley Periodicals, Inc.

  3. Decay of giant resonance E2 isoscalar in heavy nuclei. Decaimento da ressonancia gigante E2 isoescalar em nucleos pesados

    Energy Technology Data Exchange (ETDEWEB)

    Herdade, S B [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1980-01-01

    In this work, it is made a study of the giant resonance E2 isoscalar, in heavy nuclei. Fission probabilities for this resonance were determined by various authors, in different experiments, for {sup 238}U. (A.C.A.S.).

  4. Giant dipole resonances in hot nuclear matter in the model of self-relaxing mean field

    International Nuclear Information System (INIS)

    Okolowicz, J.; Ploszajczak, M.; Drozdz, S.; Caurier, E.

    1989-01-01

    The extended time-dependent Hartree-Fock approach is applied for the description of the isovector giant dipole resonance in 40 Ca at finite temperatures. The thermalization process is described using the relaxation-time ansatz for the collision integral. Strong inhibition of the giant-dipole-resonance γ-decay is found due to the fast vaporization of the nuclear surface for thermal excitation energies above E * /A ≅ 4.5 MeV. This pre-equilibrium emission of particles in the vapor phase is associated with the radial expansion of nucleus and with the vanishing particle binding energies mainly for protons. (orig.)

  5. Deformation-induced splitting of the monopole giant resonance in 24Mg

    Directory of Open Access Journals (Sweden)

    Kvasil J.

    2016-01-01

    Full Text Available The strong deformation splitting of the isoscalar giant monopole resonance (ISGMR, recently observed in (α, α′ reaction in prolate 24Mg, is analyzed in the framework of the Skyrme quasiparticle randomphase-approximation (QRPA approach with the Skyrme forces SkM*, SVbas and SkPδ. The calculations with these forces give close results and confirm that the low-energy E0-peak is caused by the deformation-induced coupling of ISGMR with the K = 0 branch of the isoscalar giant quadrupole resonance.

  6. Sum rule approach to the study of statistical decay properties of nuclear giant resonances

    International Nuclear Information System (INIS)

    Adhikari, S.K.; Hussein, M.S.

    1987-03-01

    Corrections to the well-known statistical sum rule that relates the summed transmission coefficients on the one hand and 2πΓ C.N. .ρ C.N. On the other, in the context of the statistical decay properties of nuclear giant resonances, are discussed. These corrections arise both from pre-equilibrium processes as well as from the giant resonance itself. It is shown that the compound nucleus average width is reduced as a result of these corrections. (Author) [pt

  7. Force detection of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Rugar, D.; Zueger, O.; Hoen, S.; Yannoni, C.S.; Vieth, H.M.; Kendrick, R.D.

    1994-01-01

    Micromechanical sensing of magnetic force was used to detect nuclear magnetic resonance with exceptional sensitivity and spatial resolution. With a 900 angstrom thick silicon nitride cantilever capable of detecting subfemtonewton forces, a single shot sensitivity of 1.6 x 10 13 protons was achieved for an ammonium nitrate sample mounted on the cantilever. A nearby millimeter-size iron particle produced a 600 tesla per meter magnetic field gradient, resulting in a spatial resolution of 2.6 micrometers in one dimension. These results suggest that magnetic force sensing is a viable approach for enhancing the sensitivity and spatial resolution of nuclear magnetic resonance microimaging

  8. Magnetic resonance elastometry using a single-sided permanent magnet

    International Nuclear Information System (INIS)

    Tan, Carl S; Marble, Andrew E; Ono, Yuu

    2012-01-01

    In this paper, we describe a magnetic resonance method of measuring material elasticity using a single-sided magnet with a permanent static field gradient. This method encodes sample velocity in a reciprocal space using Hahn spin-echoes with variable timing. The experimental results show a strong correlation between magnetic resonance signal attenuation and elasticity when an oscillating force is applied on the sample. This relationship in turn provides us with information about the displacement velocity experienced by the sample, which is inversely proportional to Young's modulus. The proposed method shows promise in offering a portable and cost-effective magnetic resonance elastography system. (paper)

  9. Artifacts in Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Krupa, Katarzyna; Bekiesińska-Figatowska, Monika

    2015-01-01

    Artifacts in magnetic resonance imaging and foreign bodies within the patient’s body may be confused with a pathology or may reduce the quality of examinations. Radiologists are frequently not informed about the medical history of patients and face postoperative/other images they are not familiar with. A gallery of such images was presented in this manuscript. A truncation artifact in the spinal cord could be misinterpreted as a syrinx. Motion artifacts caused by breathing, cardiac movement, CSF pulsation/blood flow create a ghost artifact which can be reduced by patient immobilization, or cardiac/respiratory gating. Aliasing artifacts can be eliminated by increasing the field of view. An artificially hyperintense signal on FLAIR images can result from magnetic susceptibility artifacts, CSF/vascular pulsation, motion, but can also be found in patients undergoing MRI examinations while receiving supplemental oxygen. Metallic and other foreign bodies which may be found on and in patients’ bodies are the main group of artifacts and these are the focus of this study: e.g. make-up, tattoos, hairbands, clothes, endovascular embolization, prostheses, surgical clips, intraorbital and other medical implants, etc. Knowledge of different types of artifacts and their origin, and of possible foreign bodies is necessary to eliminate them or to reduce their negative influence on MR images by adjusting acquisition parameters. It is also necessary to take them into consideration when interpreting the images. Some proposals of reducing artifacts have been mentioned. Describing in detail the procedures to avoid or limit the artifacts would go beyond the scope of this paper but technical ways to reduce them can be found in the cited literature

  10. Magnetic resonance in obstructive jaundice

    International Nuclear Information System (INIS)

    Gupta, R.K.; Jena, A.; Khushu, S.; Kakar, A.K.; Mishra, P.K.

    1989-01-01

    Twelve cases of obstructive jaundice in whom ultrasound failed to demonstrate the site and/or the cause of obstruction of the biliary tract were examined with magnetic resonance imaging (MRI), correctly diagnosing the site and cause of obstruction in 10 of 12 surgically proven cases. In one case of cholangiocarcinoma, the site of obstruction was well shown on MR but a definite cause could not be ascertained. In another patient who developed intermittent jaundice following surgery for choledochal cyst, MR demonstrated a solitary stone in the common hepatic duct. Surgical confirmation could not be achieved as the patient was lost to follow up. There were 6 cases of choledocholithiasis, 3 cases of gall bladder carcinoma and one case each of pancreatic adenocarcinoma and cholangiocarcinoma. It is believed that MRI will provide obstructive jaundice and will be able to minimize the use of percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) in view of its ability to perform multiplanar imaging in multiple sequences. 11 refs., figs., 1 tab

  11. Low rank magnetic resonance fingerprinting.

    Science.gov (United States)

    Mazor, Gal; Weizman, Lior; Tal, Assaf; Eldar, Yonina C

    2016-08-01

    Magnetic Resonance Fingerprinting (MRF) is a relatively new approach that provides quantitative MRI using randomized acquisition. Extraction of physical quantitative tissue values is preformed off-line, based on acquisition with varying parameters and a dictionary generated according to the Bloch equations. MRF uses hundreds of radio frequency (RF) excitation pulses for acquisition, and therefore high under-sampling ratio in the sampling domain (k-space) is required. This under-sampling causes spatial artifacts that hamper the ability to accurately estimate the quantitative tissue values. In this work, we introduce a new approach for quantitative MRI using MRF, called Low Rank MRF. We exploit the low rank property of the temporal domain, on top of the well-known sparsity of the MRF signal in the generated dictionary domain. We present an iterative scheme that consists of a gradient step followed by a low rank projection using the singular value decomposition. Experiments on real MRI data demonstrate superior results compared to conventional implementation of compressed sensing for MRF at 15% sampling ratio.

  12. Presurgical functional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Stippich, C.

    2010-01-01

    Functional magnetic resonance imaging (fMRI) is an important and novel neuroimaging modality for patients with brain tumors. By non-invasive measurement, localization and lateralization of brain activiation, most importantly of motor and speech function, fMRI facilitates the selection of the most appropriate and sparing treatment and function-preserving surgery. Prerequisites for the diagnostic use of fMRI are the application of dedicated clinical imaging protocols and standardization of the respective imaging procedures. The combination with diffusion tensor imaging (DTI) also enables tracking and visualization of important fiber bundles such as the pyramidal tract and the arcuate fascicle. These multimodal MR data can be implemented in computer systems for functional neuronavigation or radiation treatment. The practicability, accuracy and reliability of presurgical fMRI have been validated by large numbers of published data. However, fMRI cannot be considered as a fully established modality of diagnostic neuroimaging due to the lack of guidelines of the responsible medical associations as well as the lack of medical certification of important hardware and software components. This article reviews the current research in the field and provides practical information relevant for presurgical fMRI. (orig.) [de

  13. Endometrial cancer: magnetic resonance imaging.

    Science.gov (United States)

    Manfredi, R; Gui, B; Maresca, G; Fanfani, F; Bonomo, L

    2005-01-01

    Carcinoma of the endometrium is the most common invasive gynecologic malignancy of the female genital tract. Clinically, patients with endometrial carcinoma present with abnormal uterine bleeding. The role of magnetic resonance imaging (MRI) in endometrial carcinoma is disease staging and treatment planning. MRI has been shown to be the most valuable imaging mod-ality in this task, compared with endovaginal ultrasound and computed tomography, because of its intrinsic contrast resolution and multiplanar capability. MRI protocol includes axial T1-weighted images; axial, sagittal, and coronal T2-weighted images; and dynamic gadolinium-enhanced T1-weighted imaging. MR examination is usually performed in the supine position with a phased array multicoil using a four-coil configuration. Endometrial carcinoma is isointense with the normal endometrium and myometrium on noncontrast T1-weighted images and has a variable appearance on T2-weighted images demonstrating heterogeneous signal intensity. The appearance of noninvasive endometrial carcinoma on MRI is characterized by a normal or thickened endometrium, with an intact junctional zone and a sharp tumor-myometrium interface. Invasive endometrial carcinoma is characterized disruption or irregularity of the junctional zone by intermediate signal intensity mass on T2-weighted images. Invasion of the cervical stroma is diagnosed when the low signal intensity cervical stroma is disrupted by the higher signal intensity endometrial carcinoma. MRI in endometrial carcinoma performs better than other imaging modalities in disease staging and treatment planning. Further, the accuracy and the cost of MRI are equivalent to those of surgical staging.

  14. Endovascular interventional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Bartels, L W; Bakker, C J G

    2003-01-01

    Minimally invasive interventional radiological procedures, such as balloon angioplasty, stent placement or coiling of aneurysms, play an increasingly important role in the treatment of patients suffering from vascular disease. The non-destructive nature of magnetic resonance imaging (MRI), its ability to combine the acquisition of high quality anatomical images and functional information, such as blood flow velocities, perfusion and diffusion, together with its inherent three dimensionality and tomographic imaging capacities, have been advocated as advantages of using the MRI technique for guidance of endovascular radiological interventions. Within this light, endovascular interventional MRI has emerged as an interesting and promising new branch of interventional radiology. In this review article, the authors will give an overview of the most important issues related to this field. In this context, we will focus on the prerequisites for endovascular interventional MRI to come to maturity. In particular, the various approaches for device tracking that were proposed will be discussed and categorized. Furthermore, dedicated MRI systems, safety and compatibility issues and promising applications that could become clinical practice in the future will be discussed. (topical review)

  15. Magnetic resonance imaging and neurolupus

    International Nuclear Information System (INIS)

    Schott, A.M.; Colson, F.; Tebib, J.; Noel, E.; Bouvier, M.

    1990-01-01

    Magnetic resonance imaging (MRI) was assessed in the management of neuropsychiatric manifestations occurring in 6 SLE patients. The MRI scans were normal in 3 cases and was associated with remission of the symptoms except for a patient who experienced a chorea at the time of the examination. Abnormal MRI scans always revealed more lesions than CT scan. 2 different patterns of abnormalities seem to correspond to 2 specific disorders. In 2 patients with clinical presentation suggesting a cortical ischemia by vascular thrombosis, both MRI scans showed areas of abnormal high signal intensities located in the subcortical white matter. In one last patient, MRI scan revealed multiple focal areas of high signal intensities (on T 1 weighter scans) disseminated not only in the deep white matter but also in the gray one. These lesions could be depend upon demyelinisation which may occur by a local vascular process. This serie confirms the interest of MRI in the management of SLE brain involvement as well as it points out some problem of interpretation. This suggest further comparative studies especially at the real onset and during the course of neuro-psychiatric manifestations. At last, the coronal sections may be more informative for the diagnosis and patholophysiology than the horizontal ones [fr

  16. Magnetic resonance in multiple sclerosis

    International Nuclear Information System (INIS)

    Scotti, G.; Caputo, D.; Cazzullo, C.L.

    1986-01-01

    Magnetic Resonance Imaging was performed in more than 200 patients with clinical suspicion or knowledge of Multiple Sclerosis. One hundred and forty-seven (60 males and 87 females) had MR evidence of multiple sclerosis lesions. The MR signal of demyelinating plaques characteristically has prolonged T1 and T2 relaxation times and the T2-weighted spin-echo sequences are generally superior to the T1-weighted images because the lesions are better visualized as areas of increased signal intensity. MR is also able to detect plaques in the brainstem, cerebellum and within the cervical spinal cord. MR appears to be an important, non-invasive method for the diagnosis of Multiple Sclerosis and has proven to be diagnostically superior to CT, evoked potentials (EP) and CSF examination. In a selected group of 30 patients, with the whole battery of the relevant MS studies, MR was positive in 100%, CT in 33,3%, EP in 56% and CSF examination in 60%. In patients clinically presenting only with signs of spinal cord involvement or optic neuritis or when the clinical presentation is uncertain MR has proven to be a very useful diagnostic tool for diagnosis of MS by demonstrating unsuspected lesions in the cerebral hemispheres. (orig.)

  17. Myositis ossificans: magnetic resonance images

    International Nuclear Information System (INIS)

    Dosda, R.; Marti-Bonmati, L.; Concepcion, L.; Galant, J.

    1999-01-01

    Myositis ossificans is characterized by a benign, self-limiting, ossifying mass of the white tissue. In the present report, we describe the magnetic resonance (MR) images in three cases of myositis ossificans in pediatric patients, correlating the MR findings with those obtained with other radiological studies. The lesions were detected in three patients, two boys and one girl, ranging in age between 10 and 14 years. The nature of the lesion was confirmed histologically in all three cases. The MR images were obtained using superconductive units at 0.5 Teslas, with T1 and T2-weighted spin-echo and STIR sequences. In two patients, gadolinium-enhanced T1-weighted images were also obtained. As in any process of maturation, the proliferation/maturation ratio depends on the moment in the course of the lesion, which affects its MR features,. In acute phases, the soft tissue mass with an intraosseous, perilesional adematous reaction predominates, while annular calcification and lesser edema are characteristic of subacute episode. Myositis ossificans is very rare in children. The inflammatory response may present a radiological pattern difficult to distinguish from that of aggressive tumor or infection, especially in the acute phase. (Author) 7 refs

  18. Cardiovascular magnetic resonance in congenital heart disease

    International Nuclear Information System (INIS)

    Cazacu, A.; Ciubotaru, A.

    2010-01-01

    The increasing prevalence of congenital heart disease can be attributed to major improvements in diagnosis and treatment. Cardiovascular magnetic resonance imaging plays an important role in the clinical management strategy of patients with congenital heart disease. The development of new cardiovascular magnetic resonance (CMR) techniques allows comprehensive assessment of complex cardiac anatomy and function and provides information about the long-term residual post-operative lesions and complications of surgery. It overcomes many of the limitations of echocardiography and cardiac catheterization. This review evaluates the role of cardiovascular magnetic resonance imaging modality in the management of subject with congenital heart disease (CHD). (authors)

  19. Functional magnetic resonance imaging by visual stimulation

    International Nuclear Information System (INIS)

    Nishimura, Yukiko; Negoro, Kiyoshi; Morimatsu, Mitsunori; Hashida, Masahiro

    1996-01-01

    We evaluated functional magnetic resonance images obtained in 8 healthy subjects in response to visual stimulation using a conventional clinical magnetic resonance imaging system with multi-slice spin-echo echo planar imaging. Activation in the visual cortex was clearly demonstrated by the multi-slice experiment with a task-related change in signal intensity. In addition to the primary visual cortex, other areas were also activated by a complicated visual task. Multi-slice spin-echo echo planar imaging offers high temporal resolution and allows the three-dimensional analysis of brain function. Functional magnetic resonance imaging provides a useful noninvasive method of mapping brain function. (author)

  20. NMR magnetic field controller for pulsed nuclear magnetic resonance experiments

    International Nuclear Information System (INIS)

    Scheler, G.; Anacker, M.

    1975-01-01

    A nuclear magnetic resonance controller for magnetic fields, which can also be used for pulsed NMR investigations, is described. A longtime stability of 10 -7 is achieved. The control signal is generated by a modified time sharing circuit with resonance at the first side band of the 2 H signal. An exact calibration of the magnetic field is achieved by the variation of the H 1 - or of the time-sharing frequency. (author)

  1. A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

    Directory of Open Access Journals (Sweden)

    K. Bartušek

    2003-01-01

    Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

  2. Spin-flip measurements in the proton inelastic scattering on 12C and giant resonance effects

    International Nuclear Information System (INIS)

    De Leo, R.; D'Erasmo, G.; Ferrero, F.; Pantaleo, A.; Pignanelli, M.

    1975-01-01

    Differential cross sections and spin-flip probabilities (SFP) for the inelastic scattering of protons, exciting the 2 + state at 4.43 MeV in 12 C, have been measured at several incident energies between 15.9 and 37.6 MeV. The changes in the shape of the SFP angular distributions are rather limited, while the absolute values show a pronounced increase, resonant like, in two energy regions centered at about 20 and 29 MeV. The second resonance reproduces very closely the energy dependence of the E2 giant quadrupole strength found in a previous experiment. The resonance at 20 MeV should correspond to a substructure of the E1 giant dipole resonance. (Auth.)

  3. Reducing Field Distortion in Magnetic Resonance Imaging

    Science.gov (United States)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2010-01-01

    A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

  4. Double giant resonances in time-dependent relativistic mean-field theory

    International Nuclear Information System (INIS)

    Ring, P.; Podobnik, B.

    1996-01-01

    Collective vibrations in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory (RMFT). Isoscalar quadrupole and isovector dipole oscillations that correspond to giant resonances are studied, and possible excitations of higher modes are investigated. We find evidence for modes which can be interpreted as double resonances. In a quantized RMFT they correspond to two-phonon states. (orig.)

  5. Electromagnetic transitions between giant resonances within a continuum-RPA approach

    NARCIS (Netherlands)

    Rodin, VA; Dieperink, AEL

    2002-01-01

    A general continuum-RPA approach is developed to describe electromagnetic transitions between giant resonances. Using a diagrammatic representation for the three-point Green's function, an expression for the transition amplitude is derived which allows one to incorporate effects of mixing of single

  6. Can we learn about the spin-flip giant dipole resonances with pions

    International Nuclear Information System (INIS)

    Baer, H.W.

    1982-01-01

    Data and calculations for the 40 Ca(π+-,π 0 ) reactions at 164 MeV are shown which indicate that pion scattering possesses a unique signature for separately identifying the 1 - and 2 - spin-isospin components of the giant dipole resonance

  7. Direct neutron decay from the giant monopole resonance in 208Pb

    International Nuclear Information System (INIS)

    Bracco, A.; Beene, J.R.; Van Giai, N.; Bortignon, P.F.; Zardi, F.; Broglia, R.A.

    1988-01-01

    Experimental values of partial direct escape widths for the giant monopole resonance (GMR) in 208 Pb are presented and compared with predictions from various RPA models. It is found that different model Hamiltonians that reproduce equally well the energy and strength of the GMR in 208 Pb lead to direct escape width which may differ by a large factor. 1 tab

  8. Coupling effects of giant resonances on the elastic and inelastic scattering of fast neutrons

    International Nuclear Information System (INIS)

    Delaroche, J.P.; Tornow, W.

    1983-01-01

    While the inelastic scattering of high energy hadrons is commonly used for the study of giant resonances in nuclei, it is just recently that one has thought to take into account these states in the analysis of proton scattering at low incident energies (E 0 and S 1 . (Auth.)

  9. The temperature dependence of the width of the giant-dipole resonance

    International Nuclear Information System (INIS)

    Ormand, W.E.; Bortignon, P.F.; Broglia, R.A.

    1996-01-01

    The giant-dipole resonance (GDR) in 120 Sn and 208 Pb is studied as a function of excitation energy, angular momentum, and intrinsic width within the context of the adiabatic model. Theoretical evaluations of the full-width-at-half-maximum (FWHM) for the GDR strength function are compared with recent experimental data and are found to be in good agreement. (orig.)

  10. Data systematics and semidirect decay probability of the giant dipole resonance

    International Nuclear Information System (INIS)

    Ishkhanov, B.S.; Kapitonov, I.M.; Tutyn', I.A.

    1998-01-01

    Information on probability of semidirect decay of giant dipole resonance of nuclei of sd- and fp-shells (A = 16-58) is elaborated on the base of the recent (γ, χγ ' ) experimental results. The shell effect in A-dependence of this probability is discovered

  11. Isovector giant dipole resonance in hot rotating light nuclei in the calcium region

    International Nuclear Information System (INIS)

    Shanmugam, G.; Thiagasundaram, M.

    1989-01-01

    The isovector giant dipole resonances in hot rotating light nuclei in the calcium region are studied using a rotating anisotropic harmonic oscillator potential and a separable dipole-dipole residual interaction. The influence of temperature on the isovector giant dipole resonance is assumed to occur through the change of deformation of the average field only. Calculations are performed for the three nuclei /sup 40,42/Ca and /sup 46/Ti which have spherical, oblate, and prolate ground states, respectively, to see how their shape transitions at higher excited states affect the isovector giant resonance frequencies built on them. It is seen that, while the width fluctuations present at T = 0 vanish at T = 0.5 MeV in /sup 40,42/Ca, they persist up to T = 1.5 MeV in the case of /sup 46/Ti. This behavior brings out the role of temperature on shell effects which in turn affects the isovector giant dipole resonance widths

  12. The photoionization of atomic Eu in the vicinity of its giant resonance

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    1989-01-01

    It is demonstrated that the partial photoionization cross sections of outer subshells of atomic Eu in the giant resonance region are determined by the action of the 4d-electron excitations. The cross section for photoionization of the semifilled 4f 7 subshell is also entirely dominated by the interaction with 4d 10 electrons. (orig.)

  13. Collective doorways and statistical doorways: The decay properties of giant multipole resonances

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Adhikari, S.K.

    1985-01-01

    A theoretical framework for the description of the decay of giant multipole resonances is developed. It is shown that the statistical decay of the GMR is not necessarily described by the Hauser-Feschbach theory owing to the existence of a mixing parameter. The contribution of pre-equilibrium emission to the GMR decay is also discussed. (Author) [pt

  14. Direct and statistical gamma decay of the giant quadrupole resonance of 208Pb

    International Nuclear Information System (INIS)

    Dias, H.; Hussein, M.S.; Carlson, B.V.; Merchant, A.C.

    1986-03-01

    The gamma decay of the giant quadrupole resonance of 208 Pb is discussed. The relative contribution of the decay via the compound nucleus is calculated from the statistical theory. It is found that the compound decay is as important as the direct decay. (Author) [pt

  15. Neutron-skin thickness from the study of the anti-analog giant dipole resonance

    NARCIS (Netherlands)

    Krasznahorkay, A.; Stuhl, L.; Csatlós, M.; Algora, A.; Gulyás, J.; Timár, J.; Paar, N.; Vretenar, D.; Boretzky, K.; Heil, M.; Litvinov, Yu A.; Rossi, D.; Scheidenberger, C.; Simon, H.; Weick, H.; Bracco, A.; Brambilla, S.; Blasi, N.; Camera, F.; Giaz, A.; Million, B.; Pellegri, L.; Riboldi, S.; Wieland, O.; Altstadt, S.; Fonseca, M.; Glorius, J.; Göbel, K.; Heftrich, T.; Koloczek, A.; Kräckmann, S.; Langer, C.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Schmidt, S.; Sonnabend, K.; Weigand, M.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M. A.; Aumann, T.; Atar, L.; Heine, M.; Holl, M.; Movsesyan, A.; Schrock, P.; Volkov, V.; Wamers, F.; Fiori, E.; Löher, B.; Marganiec, J.; Savran, D.; Johansson, H. T.; Fernández, P. Diaz; Garg, U.; Balabanski, D. L.

    2012-01-01

    The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase

  16. A collective model description of the low lying and giant dipole resonant properties of 40424446Ca

    International Nuclear Information System (INIS)

    Weise, J.I.

    1982-01-01

    The low-lying and giant dipole resonant properties of the even-even calcium isotopes are calculated within the framework of the Gneuss-Greiner model and compared with the experimental data. In the low energy region, comparison is also made with the predictions of a coexistence model

  17. Pocket atlas of cranial magnetic resonance imaging

    International Nuclear Information System (INIS)

    Haughton, V.M.; Daniels, D.L.

    1986-01-01

    This atlas illustrates normal cerebral anatomy in magnetic resonance images. From their studies in cerebral anatomy utilizing cryomicrotome and other techniques, the authors selected more than 100 high-resolution images that represent the most clinically useful scans

  18. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  19. Fifty years of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Martinez Valderrama, Juan Crisostomo

    1997-01-01

    Short information about the main developments of nuclear magnetic resonance during their fifty existence years is presented. Beside two examples of application (HETCOR and INADEQUATE) to the structural determination of organic compounds are described

  20. Principles of nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Pykett, I.L.; Newhouse, J.H.; Buonanno, F.S.; Brady, T.J.; Goldman, M.R.; Kistler, J.P.; Pohost, G.M.

    1982-01-01

    The physical principles which underlie the phenomenon of nuclear magnetic resonance (NMR) are presented in this primer. The major scanning methods are reviewed, and the principles of technique are discussed. A glossary of NMR terms is included

  1. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA is a noninvasive test ... of the major blood vessels throughout your body. It may be performed with or without contrast material ...

  2. The role of magnetic resonance cholangiopancreatography and ...

    African Journals Online (AJOL)

    ) is accepted as the gold standard, there is a place for magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted imaging (DWI) in the diagnosis of obstructive biliary disorders. Aim: To compare the findings of MRCP with ...

  3. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... posted: How to Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI ...

  4. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... mild sedative prior to the examination. For more information about Magnetic Resonance Angiography of MRA or any ... Inc. (RSNA). To help ensure current and accurate information, we do not permit copying but encourage linking ...

  5. Chronic liver disease: evaluation by magnetic resonance

    International Nuclear Information System (INIS)

    Stark, D.D.; Goldberg, H.I.; Moss, A.A.; Bass, N.M.

    1984-01-01

    Magnetic resonance (MR) imaging distinguished hepatitis from fatty liver and cirrhosis in a woman with a history of alcohol abuse. Anatomic and physiologic manifestations of portal hypertension were also demonstrated by MR

  6. Nuclear Magnetic Resonance Trackbed Moisture Sensor System

    Science.gov (United States)

    2018-02-01

    In this initial phase, conducted from March 2015 through December 2016, Vista Clara and its subcontractor Zetica Rail successfully developed and tested a man-portable, non-invasive spot-check nuclear magnetic resonance (NMR) moisture sensor that dire...

  7. Can magnetic resonance imaging differentiate undifferentiated arthritis?

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Duer, Anne; Hørslev-Petersen, K

    2005-01-01

    A high sensitivity for the detection of inflammatory and destructive changes in inflammatory joint diseases makes magnetic resonance imaging potentially useful for assigning specific diagnoses, such as rheumatoid arthritis and psoriatic arthritis in arthritides, that remain undifferentiated after...... conventional clinical, biochemical and radiographic examinations. With recent data as the starting point, the present paper describes the current knowledge on magnetic resonance imaging in the differential diagnosis of undifferentiated arthritis....

  8. Nuclear magnetic resonance spectroscopy and imaging

    International Nuclear Information System (INIS)

    Jiang Weiping; Wang Qi; Zhou Xin

    2013-01-01

    This paper briefly introduces the basic principle of nuclear magnetic resonance (NMR). Protein's structures and functions and dynamics studied by liquid NMR are elaborated; methods for enhancing the resolution of solid state NMR and its applications are discussed; the principle of magnetic resonance imaging (MRI) is interpreted, and applications in different aspects are reviewed. Finally, the progress of NMR is commented. (authors)

  9. Concepts and indications of abdominal magnetic resonance

    International Nuclear Information System (INIS)

    Murillo Viera, Wendy

    2012-01-01

    A literature review and conceptualization was performed of the main indications of magnetic resonance studies of the abdomen and the characteristic findings for each sequence, according to organ and pathology. The radiologist has had in mind main indications for magnetic resonance studies of the abdomen, with the purpose to guide the clinician in the choice of imaging modality that works best for the patient at diagnosis [es

  10. Magnetic resonance imaging of muscle tears

    International Nuclear Information System (INIS)

    De Smet, A.A.; Fisher, D.R.; Heiner, J.P.; Keene, J.S.

    1990-01-01

    Magnetic resonance scans were obtained on 17 patients with acute, subacute, or chronic muscle tears. These patients presented with complaints of persistent pain or a palpable mass. Magnetic resonance findings were characterized according to alterations in muscle shape and the presence of abnormal high signal within the injured muscle. These areas of high signal were noted on both T1-weighted and T2-weighted scans and were presumed to represent areas of intramuscular hemorrhage. (orig.)

  11. Clinical magnetic resonance: imaging and spectroscopy

    International Nuclear Information System (INIS)

    Andrew, E.R.; Bydder, Graeme; Griffiths, John; Iles, Richard; Styles, Peter

    1990-01-01

    This book begins with a readable, comprehensive but non-mathematical introduction to the basic underlying principles of magnetic resonance. Further chapters include information on the theory and principles of MRI and MRS, the interpretation of MR images, the clinical applications and scope of MRI and MRS, practical aspects of spectroscopy and magnetic resonance, and also the practical problems associated with the siting, safety and operation of large MRI and MRS equipment. (author)

  12. Nuclear magnetic resonance method and apparatus

    International Nuclear Information System (INIS)

    Burl, M.; Young, I.R.

    1984-01-01

    A method and apparatus for determining the rate of flow of a liquid in a selected region of a body by nuclear magnetic resonance techniques are described. The method includes a sequence of applying a first magnetic pulse effective to excite nuclear magnetic resonance of a chosen nucleus within the liquid preferentially in a slice of the body which includes the selected region. A period of time (tsub(D)) is waited and then a second magnetic pulse is applied which is effective to excite nuclear magnetic resonance of the nuclei preferentially in the slice, and the free induction decay signal is measured. The whole sequence is repeated for different values of the period of time (tsub(D)). The variation in the value of the measured signal with tsub(D) is then related to the rate of flow of the liquid through the slice. (author)

  13. (e,e'f) coincidence experiments for fission decay of giant resonances in 235,238U

    International Nuclear Information System (INIS)

    Weber, T.; Heil, R.D.; Kneissl, U.; Pecho, W.; Wilke, W.; Emrich, H.J.; Kihm, T.; Knoepfle, K.T.

    1988-01-01

    Extending previous work on 238 U, 235 U(e,e'f) coincidence data were taken at 4 momentum transfers yielding both E1, E2/E0 and E3 form factors and the respective multipole strength distributions in the giant resonance region of 238 U (4 x x /Γ a is obtained as a function of excitation energy for separated multipoles. The giant E2 resonance exhibits an increased symmetric fission contribution compared to E1 and E3 resonances. (orig.)

  14. Resonance double magnetic bremsstrahlung in a strong magnetic field

    International Nuclear Information System (INIS)

    Fomin, P.I.; Kholodov, R.I.

    2003-01-01

    The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory)

  15. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and ... powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, ...

  16. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... a powerful magnetic field, radio waves and a computer to produce detailed pictures of the inside of ... powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, ...

  17. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... help detect certain chronic diseases of the nervous system, such as multiple sclerosis diagnose problems with the ... the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI) of the head uses a powerful magnetic field, radio waves and a computer to produce detailed ... there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some ...

  19. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. Your child will lie on a moveable examination ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  1. Magnetic islands created by resonant helical windings

    International Nuclear Information System (INIS)

    Fernandes, A.S.; Heller, M.V.; Caldas, I.L.

    1986-01-01

    The triggering of disruptive instabilities by resonant helical windings in large aspect-ratio tokamaks is associated to destruction of magnetic surfaces. The Chirikov condition is applied to estimate analytically the helical winding current thresholds for ergodization of the magnetic field lines. (Autor) [pt

  2. Topical questions in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Andrew, E.R.; Florida Univ., Gainesville, FL; Florida Univ., Gainesville, FL

    1989-01-01

    This paper examines a number of practical questions concerning magnetic resonance imaging. These include the choice of operating magnetic field strength, the problem of siting and screening, a procedure for securing precise slice selection and the use of paramagnetic contrast agents. (author). 5 refs

  3. NATO Advanced Study Institute on Giant Resonances in Atoms, Molecules, and Solids

    CERN Document Server

    Esteva, J; Karnatak, R

    1987-01-01

    Often, a new area of science grows at the confines between recognised subject divisions, drawing upon techniques and intellectual perspectives from a diversity of fields. Such growth can remain unnoticed at first, until a characteristic fami ly of effects, described by appropriate key words, has developed, at which point a distinct subject is born. Such is very much the case with atomic 'giant resonances'. For a start, their name itself was borrowed from the field of nuclear collective resonances. The energy range in which they occur, at the juncture of the extreme UV and the soft X-rays, remains to this day a meeting point of two different experimental techniques: the grating and the crystal spectrometer. The impetus of synchrotron spectroscopy also played a large part in developing novel methods, described by many acronyms, which are used to study 'giant resonances' today. Finally, although we have described them as 'atomic' to differentiate them from their counterparts in Nuclear Physics, their occurrence ...

  4. Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

    Energy Technology Data Exchange (ETDEWEB)

    Lyutorovich, N.; Tselyaev, V. [Physical Faculty, St. Petersburg State University, RU-198504 St. Petersburg (Russian Federation); Speth, J., E-mail: J.Speth@fz-juelich.de [Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich (Germany); Krewald, S.; Grümmer, F. [Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich (Germany); Reinhard, P.-G. [Institut für Theoretische Physik II, Universität Erlangen-Nürnberg, D-91058 Erlangen (Germany)

    2015-10-07

    We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree–Fock ground state and the excitation spectra within random-phase approximation (RPA) and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA). All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.

  5. Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

    Directory of Open Access Journals (Sweden)

    N. Lyutorovich

    2015-10-01

    Full Text Available We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree–Fock ground state and the excitation spectra within random-phase approximation (RPA and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA. All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.

  6. A microscopic study of giant resonances in nuclei near drip lines

    CERN Document Server

    Sagawa, H; Zhang, X Z

    1999-01-01

    We study giant resonances using the self-consistent Hartree-Fock calculation plus the random phase approximation with Skyrme interactions. Including simultaneously both the isoscalar and the isovector correlation the RPA response function is calculated in the coordinate space so as to take properly into account the continuum effect. Giant monopole states are discussed in relation with the nuclear compression modulus of the nuclear matter K sub n sub m. The core polarization charges are also discussed in comparison with recent empirical data in sup 1 sup 0 sup 0 Sn region.

  7. Isoscalar giant resonances for nuclei with mass between 56 and 60

    International Nuclear Information System (INIS)

    Lui, Y.-W.; Youngblood, D.H.; Clark, H.L.; Tokimoto, Y.; John, B.

    2006-01-01

    The giant resonance region from 10 MeV x 56 Fe, 58 Ni, and 60 Ni has been studied with inelastic scattering of 240 MeV α particles at small angles, including 0 deg. Most of the expected isoscalar E0 and E2 strength has been identified below E x =40 MeV. Between 56 and 72% of the isoscalar E1 strength has been located in these nuclei. The mass dependence of the giant monopole energy between A=40 and 90 is compared to relativistic and nonrelativistic calculations for interactions with compressibility of nuclear matter K NM ∼211-225 MeV

  8. Giant Magnetoresistance in Carbon Nanotubes with Single-Molecule Magnets TbPc2.

    Science.gov (United States)

    Krainov, Igor V; Klier, Janina; Dmitriev, Alexander P; Klyatskaya, Svetlana; Ruben, Mario; Wernsdorfer, Wolfgang; Gornyi, Igor V

    2017-07-25

    We present experimental results and a theoretical model for the gate-controlled spin-valve effect in carbon nanotubes with side-attached single-molecule magnets TbPc 2 (Terbium(III) bis-phthalocyanine). These structures show a giant magnetoresistance up to 1000% in experiments on single-wall nanotubes that are tunnel-coupled to the leads. The proposed theoretical model combines the spin-dependent Fano effect with Coulomb blockade and predicts a spin-spin interaction between the TbPc 2 molecules, mediated by conducting electrons via the charging effect. This gate-tuned interaction is responsible for the stable magnetic ordering of the inner spins of the molecules in the absence of magnetic field. In the case of antiferromagnetic arrangement, electrons with either spin experience the scattering by the molecules, which results in blocking the linear transport. In strong magnetic fields, the Zeeman energy exceeds the effective antiferromagnetic coupling and one species of electrons is not scattered by molecules, which leads to a much lower total resistance at the resonant values of gate voltage, and hence to a supramolecular spin-valve effect.

  9. Basis of the nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Bahceli, S.

    1996-08-01

    The aim of this book which is translated from English language is to explain the physical and mathematical basis of nuclear magnetic resonance (NMR). There are nine chapters covering different aspects of NMR. In the firs chapter fundamental concepts of quantum mechanics are given at a level suitable for readers to understand NMR fully. The remaining chapters discuss the magnetic properties of nucleus, the interactions between atoms and molecules, continuous wave NMR, pulsed NMR, nuclear magnetic relaxation and NMR of liquids

  10. Magnetic nanoparticles in magnetic resonance imaging and diagnostics.

    Science.gov (United States)

    Rümenapp, Christine; Gleich, Bernhard; Haase, Axel

    2012-05-01

    Magnetic nanoparticles are useful as contrast agents for magnetic resonance imaging (MRI). Paramagnetic contrast agents have been used for a long time, but more recently superparamagnetic iron oxide nanoparticles (SPIOs) have been discovered to influence MRI contrast as well. In contrast to paramagnetic contrast agents, SPIOs can be functionalized and size-tailored in order to adapt to various kinds of soft tissues. Although both types of contrast agents have a inducible magnetization, their mechanisms of influence on spin-spin and spin-lattice relaxation of protons are different. A special emphasis on the basic magnetism of nanoparticles and their structures as well as on the principle of nuclear magnetic resonance is made. Examples of different contrast-enhanced magnetic resonance images are given. The potential use of magnetic nanoparticles as diagnostic tracers is explored. Additionally, SPIOs can be used in diagnostic magnetic resonance, since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.

  11. Magnetic resonance imaging of the fetal brain.

    Science.gov (United States)

    Tee, L Mf; Kan, E Yl; Cheung, J Cy; Leung, W C

    2016-06-01

    This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

  12. Magnetic resonance imaging: effects of magnetic field strength

    International Nuclear Information System (INIS)

    Crooks, L.E.; Arakawa, M.; Hoenninger, J.; McCarten, B.; Watts, J.; Kaufman, L.

    1984-01-01

    Magnetic resonance images of the head, abdomen, and pelvis of normal adult men were obtained using varying magnetic field strength, and measurements of T1 and T2 relaxations and of signal-to-noise (SN) ratios were determined. For any one spin echo sequence, gray/white matter contrast decreases and muscle/fat contrast increases with field. SN levels rise rapidly up to 3.0 kgauss and then change more slowly, actually dropping for muscle. The optimum field for magnetic resonance imaging depends on tissue type, body part, and imaging sequence, so that it does not have a unique value. Magnetic resonance systems that operate in the 3.0-5.0 kgauss range achieve most or all of the gains that can be achieved by higher magnetic fields

  13. Giant magnetic anisotropy of rare-earth adatoms and dimers adsorbed by graphene oxide.

    Science.gov (United States)

    Zhang, Kai-Cheng; Li, Yong-Feng; Liu, Yong; Zhu, Yan; Shi, Li-Bin

    2017-05-24

    Nowadays, transition-metal adatoms and dimers with giant magnetic anisotropy have attracted much attention due to their potential applications in data storage, spintronics and quantum computations. Using density-functional calculations, we investigated the magnetic anisotropy of the rare-earth adatoms and dimers adsorbed by graphene oxide. Our calculations reveal that the adatoms of Tm, Er and Sm possess giant magnetic anisotropy, typically larger than 40 meV. When the dimers of (Tm,Er,Sm)-Ir are adsorbed onto graphene oxide, the magnetic anisotropy even exceeds 200 meV. The magnetic anisotropy can be tuned by the external electric field as well as the environment.

  14. Diagnostic apparatus employing nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Hoshino, K.; Yamada, N.; Yoshitome, E.; Matsuura, H.

    1987-01-01

    An NMR diagnostic apparatus is described comprising means for applying a primary magnetic field to a subject; means for applying RF pulses to the subject to give nuclear magnetic resonance to the nuclei of atoms in the subject; means for applying gradient magnetic fields to project an NMR signal of the nuclei at least in one direction; means for observing the NMR signal projected by the gradient magnetic fields applying means; and arithmetic means for constructing a distribution of information on resonance energy as an image from an output signal from the observing means; wherein the gradient magnetic fields applying means comprises means for applying the gradient magnetic fields at a predetermined time and for not applying the gradient magnetic fields at another predetermined time, during the time period of one view; and wherein the gradient magnetic fields applying means further comprises means for measuring the NMR signal during the predetermined time when the gradient magnetic fields are applied, and means for measuring the intensity of the primary magnetic field during the other predetermined time when no gradient magnetic fields are applied

  15. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... vision or seizures help detect certain chronic diseases of the nervous system, such as multiple sclerosis diagnose problems with the ... moveable examination table that slides into the center of the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  16. Embroidered Coils for Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Michael I. Newton

    2013-04-01

    Full Text Available Magnetic resonance imaging is a widely used technique for medical and materials imaging. Even though the objects being imaged are often irregularly shaped, suitable coils permitting the measurement of the radio-frequency signal in these systems are usually made of solid copper. One problem often encountered is how to ensure the coils are both in close proximity and conformal to the object being imaged. Whilst embroidered conductive threads have previously been used as antennae in mobile telecommunications applications, they have not previously been reported for use within magnetic resonance. In this paper we show that an embroidered single loop coil can be used in a commercial unilateral nuclear magnetic resonance system as an alternative to a solid copper. Data is presented showing the determination of both longitudinal (T1 and effective transverse (T2eff relaxation times for a flat fabric coil and the same coil conformed to an 8 cm diameter cylinder. We thereby demonstrate the principles required for the wider use of fabric based conformal coils within nuclear magnetic resonance and magnetic resonance imaging.

  17. Surface and temperature effects in isovector giant resonances

    International Nuclear Information System (INIS)

    Lipparini, E.; Stringari, S.

    1988-01-01

    Using the liquid droplet model (LDM) we investigate three different sum rules for the isovector dipole and monopole excitations. Analytical formulae are derived for the excitation energies of these resonances and the predictions are compared with experiments. The role of the surface and the effects of temperature are explicitly discussed. (orig.)

  18. Magnetic resonance signal moment determination using the Earth's magnetic field

    KAUST Repository

    Fridjonsson, Einar Orn; Creber, Sarah A.; Vrouwenvelder, Johannes S.; Johns, Michael L.

    2015-01-01

    We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth's magnetic field system.

  19. Magnetic resonance signal moment determination using the Earth's magnetic field

    KAUST Repository

    Fridjonsson, Einar Orn

    2015-03-01

    We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth\\'s magnetic field system.

  20. Generation of nuclear magnetic resonance images

    International Nuclear Information System (INIS)

    Beckmann, N.X.

    1986-01-01

    Two generation techniques of nuclear magnetic resonance images, the retro-projection and the direct transformation method are studied these techniques are based on the acquisition of NMR signals which phases and frequency components are codified in space by application of magnetic field gradients. The construction of magnet coils is discussed, in particular a suitable magnet geometry with polar pieces and air gap. The obtention of image contrast by T1 and T2 relaxation times reconstructed from generated signals using sequences such as spin-echo, inversion-recovery and stimulated echo, is discussed. The mathematical formalism of matrix solution for Bloch equations is also presented. (M.C.K.)

  1. Susceptibility effects in nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ziener, Christian Herbert

    2008-01-01

    The properties of dephasing and the resulting relaxation of the magnetization are the basic principle on which all magnetic resonance imaging methods are based. The signal obtained from the gyrating spins is essentially determined by the properties of the considered tissue. Especially the susceptibility differences caused by magnetized materials (for example, deoxygenated blood, BOLD-effect) or magnetic nanoparticles are becoming more important for biomedical imaging. In the present work, the influence of such field inhomogeneities on the NMR-signal is analyzed. (orig.)

  2. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... a risk, depending on their nature and the strength of the MRI magnet. Many implanted devices will ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... a risk, depending on their nature and the strength of the MRI magnet. Many implanted devices will ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy ...

  4. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... and extremities. Tell your doctor about your child’s health problems, medications, recent surgeries and allergies. The magnetic ... the radiologist if your child has any serious health problems or has recently had surgery. Some conditions, ...

  5. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... doctor about your child’s health problems, medications, recent surgeries and allergies. The magnetic field is not harmful, ... to the heart muscle evaluate findings following cardiovascular surgery In the abdominal and pelvic region, MRI is ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... material called gadolinium, which is less likely to cause an allergic reaction than iodinated contrast material. Tell ... magnetic field is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... distort images of the facial area or brain, so you should let the radiologist know about them. ... MRI units, called short-bore systems , are designed so that the magnet does not completely surround you. ...

  8. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... distort images of the facial area or brain, so the radiologist should be aware of them. Parents ... MRI units, called short-bore systems , are designed so that the magnet does not completely surround you. ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... x-ray contrast material, drugs, food, or the environment, or if you have asthma. The contrast material ... are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or ...

  10. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... x-ray contrast material, drugs, food, or the environment, or if your child has asthma. The contrast ... are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or ...

  11. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in ... the MRI equipment look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in ... does the equipment look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... an MRI scan, but this is rare. Tooth fillings and braces usually are not affected by the magnetic field, but they may distort images of the facial area or brain, so you should let the ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... lodged in the eyes are particularly important. Tooth fillings and braces usually are not affected by the magnetic field, but they may distort images of the facial area or brain, so the radiologist should be ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie ... your skin at the site of the IV tube insertion. Some patients may sense a temporary metallic ...

  16. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. Your child will ... skin irritation at the site of the IV tube insertion. Some patients may sense a temporary metallic ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

  18. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... regular daily routine and have him/her take food and medications as usual. Some MRI examinations may ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  20. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... if your child has any implanted medical or electronic devices. Inform your doctor and the technologist prior ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. ... signals that are detected by the coils. The electric current does not come in contact with the ...

  2. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. ... signals that are detected by the coils. The electric current does not come in contact with the ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Magnetic ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... pregnant. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most ... number of abrupt onset or long-standing symptoms. It can help diagnose conditions such as: brain tumors ...

  5. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... allergies. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most ... cord is needed, MRI is useful because of its ability to see through the skull and the ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media MR Angiography ( ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... allergies and whether there’s a possibility you are pregnant. The magnetic field is not harmful, but it ... if there is any possibility that they are pregnant. MRI has been used for scanning patients since ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI) procedure View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic ...

  10. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... fluid spaces within the brain (ventricles) causes of epilepsy (seizure) hemorrhage in selected trauma patients certain chronic ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  13. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... two-way intercom. Many MRI centers allow a parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... your child’s health problems, medications, recent surgeries and allergies. The magnetic field is not harmful, but it ... the exam if your child has a known allergy to contrast material. Your child should wear loose, ...

  15. Magnetic resonance imaging of breast implants.

    Science.gov (United States)

    Shah, Mala; Tanna, Neil; Margolies, Laurie

    2014-12-01

    Silicone breast implants have significantly evolved since their introduction half a century ago, yet implant rupture remains a common and expected complication, especially in patients with earlier-generation implants. Magnetic resonance imaging is the primary modality for assessing the integrity of silicone implants and has excellent sensitivity and specificity, and the Food and Drug Administration currently recommends periodic magnetic resonance imaging screening for silent silicone breast implant rupture. Familiarity with the types of silicone implants and potential complications is essential for the radiologist. Signs of intracapsular rupture include the noose, droplet, subcapsular line, and linguine signs. Signs of extracapsular rupture include herniation of silicone with a capsular defect and extruded silicone material. Specific sequences including water and silicone suppression are essential for distinguishing rupture from other pathologies and artifacts. Magnetic resonance imaging provides valuable information about the integrity of silicone implants and associated complications.

  16. Angular correlation experiments for the study of giant multipole resonances and currents of the second kind in atomic nuclei

    International Nuclear Information System (INIS)

    1986-03-01

    The project dealt with angular correlation experiments for the study of giant multipole resonances and currents of the second kind in atomic nuclei. Both partial projects were worked in the period of the report. (orig.) [de

  17. Damping of isovector giant dipole resonances in hot even-even spherical nuclei

    International Nuclear Information System (INIS)

    Dang, N.D.

    1989-01-01

    An approach based on the finite temperature quasiparticle phonon nuclear model (FT-QPNM) with the couplings to (2p2h) states at finite temperature taken into account is suggested for calculations of the damping of giant multipole resonances in hot even-even spherical nuclei. The strength functions for the isovector giant dipole resonance (IV-GDR) are calculated in 58 Ni and 90 Zr for a range of temperatures up to 3 MeV. The results show that the contribution of the interactions with (2p2h) configurations to the IV-GDR spreading width changes weakly with varying temperature. The IV-GDR centroid energy decreases slightly with increasing temperature. The nonvanishing superfluid pairing gap due to thermal fluctuations is included. (orig.)

  18. Multipole giant resonances of 12C nucleus electro excitation in intermediate coupling model

    International Nuclear Information System (INIS)

    Goncharova, N.G.; Zhivopistsev, F.A.

    1977-01-01

    Multipole giant resonances in 12 C electroexcitation are considered using the shell model with coupling. Cross sections are calculated for the states of 1 - , 2 - , 3 - , 4 - , at T=1. The distributions of the transverse form factor at transferred momenta equal to q approximately 0.75, 1.04, 1.22 and 1.56 Fm -1 and the longitudinal form factor for q = 0.75, 1.04, 1.56 Fm -1 are presented. For the excitation energies in the range from 18 to 28 MeV positive-parity states have a small contribution in the cross section. The distribution of the total form factor in the excitation energies is given. It is concluded that the multipole giant resonances of anomalous parity levels calculated within the interatomic-coupling shell model show a satisfactorily close agreement with the behavior of experimental form factors in the excitation energy range from 18 to 28 MeV

  19. Dramatic distortion of the 4d giant resonance by the C{sub 60} fullerene shell

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M Ya [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Baltenkov, A S [Arifov Institute of Electronics, Akademgorodok, 700125 Tashkent (Uzbekistan); Chernysheva, L V [A F Ioffe Physical-Technical Institute, St Petersburg 194021 (Russian Federation); Felfli, Z [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, GA 30314 (United States); Msezane, A Z [Department of Physics and Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, GA 30314 (United States)

    2005-05-28

    The photoionization cross section for the endohedral Xe at C{sub 60} atom is investigated within the framework of representing the C{sub 60} by a delta-type potential. Results demonstrate that in Xe at C{sub 60}, the 4d giant resonance is distorted significantly when compared with that of the isolated Xe atom. The reflection of the photoelectron waves by the C{sub 60} causes strong oscillations in the photoionization cross section resulting in the replacement of the Xe 4d giant resonance by four prominent peaks. The approximation of C{sub 60} by an infinitely thin real potential preserves reasonably well the sum rule for the 4d electrons but modifies the dipole polarizability of the 4d shell. (letter to the editor)

  20. Magnetic resonance enterography in pediatric celiac disease.

    Science.gov (United States)

    Koc, Gonca; Doganay, Selim; Sevinc, Eylem; Deniz, Kemal; Chavhan, Govind; Gorkem, Sureyya B; Karacabey, Neslihan; Dogan, Mehmet S; Coskun, Abdulhakim; Aslan, Duran

    To assess if magnetic resonance enterography is capable of showing evidence/extent of disease in pediatric patients with biopsy-proven celiac disease by comparing with a control group, and to correlate the magnetic resonance enterography findings with anti-endomysial antibody level, which is an indicator of gluten-free dietary compliance. Thirty-one pediatric patients (mean age 11.7±3.1 years) with biopsy-proven celiac disease and 40 pediatric patients as a control group were recruited in the study. The magnetic resonance enterography images of both patients with celiac disease and those of the control group were evaluated by two pediatric radiologists in a blinded manner for the mucosal pattern, presence of wall thickening, luminal distention of the small bowel, and extra-intestinal findings. Patient charts were reviewed to note clinical features and laboratory findings. The histopathologic review of the duodenal biopsies was re-conducted. The mean duration of the disease was 5.6±1.8 years (range: 3-7.2 years). In 24 (77%) of the patients, anti-endomysial antibody levels were elevated (mean 119.2±66.6RU/mL). Magnetic resonance enterography revealed normal fold pattern in all the patients. Ten (32%) patients had enlarged mesenteric lymph nodes. Although a majority of the patients had elevated anti-endomysial antibody levels indicating poor dietary compliance, magnetic resonance enterography did not show any mucosal abnormality associated with the inability of magnetic resonance enterography to detect mild/early changes of celiac disease in children. Therefore, it may not be useful for the follow-up of pediatric celiac disease. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  1. The giant-dipole-resonance effect in coulomb excitation of 10B

    International Nuclear Information System (INIS)

    Vermeer, W.J.; Zabel, T.H.; Esat, M.T.; Kuehner, J.A.; Spear, R.H.; Baxter, A.M.

    1982-04-01

    Coulomb excitation of the 0.718-MeV, Jsup(π) = 1 + , first excited state of 10 B has been studied using projectile excitation by 208 Pb and observing the backward scattered particles. The results give a clear indication of the virtual excitation of the giant dipole resonance as a second-order effect. The observed magnitude is consistent with the usual hydrodynamic model estimate and with a recent shell-model calculation

  2. Decay of giant resonances states in radiative pion capture by 1p shell nuclei

    International Nuclear Information System (INIS)

    Dogotar, G.E.

    1978-01-01

    The decay of the giant resonance states excited in tthe radiative pion capture on the 9 Be, 11 B, 13 C and 14 N nuclei is considered in the shell model with intermediate coupling. It is shown that the excited states in the daughter nuclei (A-1, Z-1) are mainly populated by intermediate states with spin by two units larger than the spin of the target nuclei. Selected coincidence experiments are proposed

  3. Nuclear giant resonances in coordinate space. A semiclassical density functional approach

    International Nuclear Information System (INIS)

    Gleissl, P.; Brack, M.; Meyer, J.; Quentin, P.

    1987-01-01

    We discuss the semiclassical description of nuclear giant resonances (GR) using a realistic Skyrme force (SkM*) and complete ETF density functionals. We present monopole (0 + ) eigenmodes of isoscalar (I=0) and isovector (I=1) type, which are in good agreement with experiment, and the corresponding m 1 and m 3 sum rules. We also present the temperature dependence of some typical GR energies (0 + , I=0,1; 1 - , I=1; 2 + , I=0) in 208 Pb

  4. Magnetic resonance imaging of popliteal artery pathologies

    International Nuclear Information System (INIS)

    Holden, Andrew; Merrilees, Stephen; Mitchell, Nicola; Hill, Andrew

    2008-01-01

    This paper illustrates examples of popliteal artery pathologies imaged with contrast enhanced magnetic resonance angiography (CE-MRA) and magnetic resonance imaging (MRI) at a single tertiary referral centre. Popliteal artery pathologies were identified in 1710 patients referred over a 6-year period with symptoms suggesting lower limb arterial occlusive disease. Common pathologies such as atherosclerotic occlusive disease, thromboemboli and aneurysm disease are discussed as well as unusual pathologies such as cystic adventitial disease, mycotic aneurysm and arterial entrapment. The combination of CE-MRA and the excellent soft tissue resolution of MRI allow detailed evaluation of arterial and peri-arterial pathologies, and facilitate appropriate management decisions

  5. Magnetic resonance imaging of popliteal artery pathologies

    Energy Technology Data Exchange (ETDEWEB)

    Holden, Andrew [Department of Radiology, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: andrewh@adhb.govt.nz; Merrilees, Stephen [Department of Radiology, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: smerrilees@adhb.govt.nz; Mitchell, Nicola [Department of Radiology, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: nmit010@ec.auckland.ac.nz; Hill, Andrew [Department of Vascular Surgery, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: ahill@adhb.govt.nz

    2008-07-15

    This paper illustrates examples of popliteal artery pathologies imaged with contrast enhanced magnetic resonance angiography (CE-MRA) and magnetic resonance imaging (MRI) at a single tertiary referral centre. Popliteal artery pathologies were identified in 1710 patients referred over a 6-year period with symptoms suggesting lower limb arterial occlusive disease. Common pathologies such as atherosclerotic occlusive disease, thromboemboli and aneurysm disease are discussed as well as unusual pathologies such as cystic adventitial disease, mycotic aneurysm and arterial entrapment. The combination of CE-MRA and the excellent soft tissue resolution of MRI allow detailed evaluation of arterial and peri-arterial pathologies, and facilitate appropriate management decisions.

  6. Magnetic elliptical polarization of Schumann resonances

    International Nuclear Information System (INIS)

    Sentman, D.D.

    1987-01-01

    Measurements of orthogonal, horizontal components of the magnetic field in the ELF range obtained during September 1985 show that the Schumann resonance eigenfrequencies determined separately for the north-south and east-west magnetic components differ by as much as 0.5 Hz, suggesting that the underlying magnetic signal is not linearly polarized at such times. The high degree of magnetic ellipticity found suggests that the side multiplets of the Schumann resonances corresponding to azimuthally inhomogeneous normal modes are strongly excited in the highly asymmetric earth-ionosphere cavity. The dominant sense of polarization over the measurement passband is found to be right-handed during local daylight hours, and to be left-handed during local nighttime hours. 16 references

  7. First measurement of isoscalar giant resonances in a stored-beam experiment

    Directory of Open Access Journals (Sweden)

    J.C. Zamora

    2016-12-01

    Full Text Available A new technique developed for measuring nuclear reactions at low momentum transfer with stored beams in inverse kinematics was successfully used to study isoscalar giant resonances. The experiment was carried out at the experimental heavy-ion storage ring (ESR at the GSI facility using a stored 58Ni beam at 100 MeV/u and an internal helium gas-jet target. In these measurements, inelastically scattered α-recoils at very forward center-of-mass angles (θcm≤1.5° were detected with a dedicated setup, including ultra-high vacuum compatible detectors. Experimental results indicate a dominant contribution of the isoscalar giant monopole resonance at this very forward angular range. It was found that the monopole contribution exhausts 79−11+12% of the energy-weighted sum rule (EWSR, which agrees with measurements performed in normal kinematics. This opens up the opportunity to investigate the giant resonances in a large domain of unstable and exotic nuclei in the near future. It is a fundamental milestone towards new nuclear reaction studies with stored ion beams.

  8. Proton magnetic resonance spectroscopy and perfusion magnetic resonance imaging in the evaluation of musculoskeletal tumors

    International Nuclear Information System (INIS)

    Costa, Flavia Martins; Setti, Marcela; Vianna, Evandro Miguelote; Domingues, Romulo Cortes; Meohas, Walter; Rezende, Jose Francisco; Gasparetto, Emerson Leandro

    2009-01-01

    Objective: To assess the role of proton magnetic resonance spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in the differentiation between malignant and benign musculoskeletal tumors. Materials And Methods: Fifty-five patients with musculoskeletal tumors (27 malignant and 28 benign) were studied. The examinations were performed in a 1.5 T magnetic resonance scanner with standard protocol, and single voxel proton magnetic resonance spectroscopy with 135 msec echo time. The dynamic contrast study was performed using T1-weighted gradient-echo sequence after intravenous gadolinium injection. Time signal intensity curves and slope values were calculated. The statistical analysis was performed with the Levene's test, followed by a Student's t-test, besides the Pearson's chi-squared and Fischer's exact tests. Results: Proton magnetic resonance spectroscopy sensitivity, specificity and accuracy were, respectively, 87.5%, 92.3% and 90.9% (p < 0.0001). Statistically significant difference was observed in the slope (%/min) between benign (mean, 27.5%/min) and malignant (mean, 110.9%/min) lesions (p < 0.0001). Conclusion: The time-intensity curve and slope values using dynamic-enhanced perfusion magnetic resonance imaging in association with the presence of choline peak demonstrated by single voxel magnetic resonance spectroscopy study are useful in the differentiation between malignant and benign musculoskeletal tumors. (author)

  9. Sensing the quantum behaviour of magnetic nanoparticles by electron magnetic resonance.

    Science.gov (United States)

    Fittipaldi, M; Mercatelli, R; Sottini, S; Ceci, P; Falvo, E; Gatteschi, D

    2016-02-07

    We have investigated Magnetic Nanoparticles (MNPs) of spinel type iron oxide (of approximately 8 nm) mineralized in the internal cavity of the bioreactor ferritin nanocage. In particular, we have used Electron Magnetic Resonance, EMR, spectroscopy and taken advantage of the capacity of the protein shells to control the size of the MNPs. EMR measurements in perpendicular and parallel configurations have been recorded at various temperatures. A model based on the giant spin is used to interpret the experimental results. The analysis indicates that the observed quantum behaviour has to be ascribed to the whole MNP and that the thermal population of excited spin states has a strong influence in the EMR behaviour of MNPs.

  10. Decay of the isoscalar giant monopole resonance in 208Pb and 238U

    International Nuclear Information System (INIS)

    Woude, A. van der

    1985-01-01

    In this paper, the neutron decay of the giant monopole resonance (GMR) of 208 Pb and the alpha decay of the GMR of 238 U is studied. The GMR is excited by inelastic alpha-scattering at small angles (0-3deg) using 120 MeV alpha particles. The interference of other processes like the knock-out process with the particle decay of these resonances is considered. Coincidence neutron and alpha spectra are presented, as well as E2/E0 strength distributions. (Auth.)

  11. Photoexcitation by gamma-ray scattering near threshold and giant dipole resonance

    International Nuclear Information System (INIS)

    Lakosi, L.; Safar, J.; Veres, A.; Sekine, T.; Kaji, H.; Yoshihara, K.

    1993-01-01

    Photoexcitation of 4.5 h half-life 115m In and 56 min half-life 103m Rh isomers by inelastic gamma-ray scattering near threshold and in the giant dipole resonance region has been reviewed. In disagreement with earlier experimental results available in the literature, but in good agreement with our experiments published recently, present calculations indicate that above the photoneutron emission threshold the isomer excitation drops abruptly and remains orders of magnitude smaller than at the threshold, even around resonance maximum. (author)

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... ill effects on pregnant women or their unborn babies. However, because the unborn baby will be in a strong magnetic field, pregnant ... intravenous contrast indicate mothers should not breastfeed their babies for 24-48 hours after contrast medium is ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... epilepsy (seizure) hemorrhage in selected trauma patients certain chronic conditions, such as multiple sclerosis disorders of the ... a very small chance of irritation of your skin at the site of the IV tube insertion. Some ... Images related to Magnetic ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic ... patient to have an allergy to a gadolinium-based contrast agent used for MRI than the iodine- ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  16. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... which they come. The MR scanner captures this energy and creates a picture of the tissues scanned based on this information. The magnetic field is produced by passing an electric current through wire coils in most MRI units. ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... which they come. The MR scanner captures this energy and creates a picture of the tissues scanned based on this information. The magnetic field is produced by passing an electric current through wire coils in most MRI units. ...

  18. Nuclear magnetic resonance (NMR) tomography

    International Nuclear Information System (INIS)

    Skalpe, I.O.

    1984-01-01

    A brief survey of the working principle of the NMR technique in diagnostical medicine is given. Its clinical usefulness for locating tumors, diagnosing various other diseases, such as some mental illnesses and multiple sclerosis, and its possibilities for studying biochemical processes in vivo are mentioned. The price of NMR image scanners and the problems of the strong magnetic field around the machines are mentioned

  19. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... MRI equipment look like? How does the procedure work? How is the ... use to diagnose medical conditions. MRI uses a powerful magnetic field, radio frequency ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... the equipment look like? How does the procedure work? How is the ... use to diagnose medical conditions. MRI uses a powerful magnetic field, radio frequency ...

  1. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... to see, hear and speak with your child at all times using a two-way intercom. Many MRI centers allow a parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given ...

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... able to see, hear and speak with you at all times using a two-way intercom. Many MRI centers allow a friend or parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and other cranial structures that are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and may require an injection of a ...

  4. Magnetic resonance investigation of magnetic-labeled baker's yeast cells

    International Nuclear Information System (INIS)

    Godoy Morais, J.P.M.; Azevedo, R.B.; Silva, L.P.; Lacava, Z.G.M.; Bao, S.N.; Silva, O.; Pelegrini, F.; Gansau, C.; Buske, N.; Safarik, I.; Safarikova, M.; Morais, P.C.

    2004-01-01

    In this study, the interaction of DMSA-coated magnetite nanoparticles (5 and 10 nm core-size) with Saccharomyces cerevisae was investigated using magnetic resonance (MR) and transmission electron microscopy (TEM). The TEM micrographs revealed magnetite nanoparticles attached externally to the cell wall. The MR data support the strong interaction among the nanoparticles supported by the cells. A remarkable shift in the resonance field was used as signature of particle attachment to the cell wall

  5. Semiclassical approach to giant resonances of rotating nuclei

    International Nuclear Information System (INIS)

    Winter, J.

    1983-01-01

    Quadrupole and isovector dipole resonances of rotating nuclei are investigated in the frame-work of Vlasov equations transformed to a rotating system of reference, which are based on the time-dependent Hartree-method for schematic forces. The parameter free model of the self-consistent vibrating harmonic oscillator potential for the quadrupole mode is extended to a coupling to rotation, which also includes large-amplitude behaviour. A generalization to an exactly solvable two-liquid model describing the isovector mode is established; for rotating nuclei Hilton's explicit result for the eigenfrequencies is obtained. The advantage of using the concept of the classical kinetic momentum in a rotating system also in quantum-mechanical descriptions is demonstrated. It completes the standard transformation of density matrices by a time-odd part realized in a phase-factor and permits a more direct interpretation of rotation effects in terms of the classical forces of inertia. (author)

  6. resonant inverter supplied interior permanent magnet (ipm)

    African Journals Online (AJOL)

    user

    [5] Zhenyue Hong, “DC-voltage link resonant inverters”, Department of Electrical and. Electronic Engineering University of. Canterbury, New Zealand. [6] Kalyan Kumar Halder, Naruttam Kumar Roy and B.C. Ghosh, “Position Sensorless. Control for an Interior Permanent Magnet. Synchronous Motor SVM Drive with ANN.

  7. Magnetic resonance imaging in radiotherapy treatment planning

    NARCIS (Netherlands)

    Moerland, Marinus Adriaan

    1996-01-01

    From its inception in the early 1970's up to the present, magnetic resonance imaging (MRI) has evolved into a sophisticated technique, which has aroused considerable interest in var- ious subelds of medicine including radiotherapy. MRI is capable of imaging in any plane and does not use ionizing

  8. Pharyngeal branchial cyst: magnetic resonance findings

    Energy Technology Data Exchange (ETDEWEB)

    Cerezal, L.; Canga, A. [Department of Radiology of the ' Santa Cruz' Hospital Liencres, Cantabria (Spain); Morales, C. [Department of Otorhinolaryngology of the ' Sierrallana' Hospital Torrelavega, Cantabria (Spain); Abascal, F.; Usamentiaga, E.; Bustamante, M. [Department of Radiology of the University Hospital ' Marques de Valdecilla' , Av. de Valdecilla s/n Santander 39008 (Spain); Olcinas, O. [Department of Pathology of the University Hospital ' Marques de Valdecilla' , Av. de Valdecilla s/n Santander 39008 (Spain)

    1998-11-01

    An unusual case of pharyngeal cyst in a 25-year-old man studied by Magnetic Resonance (MR) is described. Anatomic location and pathological findings indicated the second branchial pouch origin. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Pharyngeal branchial cyst: magnetic resonance findings

    International Nuclear Information System (INIS)

    Cerezal, L.; Canga, A.; Morales, C.; Abascal, F.; Usamentiaga, E.; Bustamante, M.; Olcinas, O.

    1998-01-01

    An unusual case of pharyngeal cyst in a 25-year-old man studied by Magnetic Resonance (MR) is described. Anatomic location and pathological findings indicated the second branchial pouch origin. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  10. Numerical methods in electron magnetic resonance

    International Nuclear Information System (INIS)

    Soernes, A.R.

    1998-01-01

    The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system

  11. Numerical methods in electron magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Soernes, A.R

    1998-07-01

    The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system.

  12. Magnetic resonance angiography in meningovascular syphilis

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, J [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Soriano, G [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Zubieta, J L [Servicio de Neuroradiologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Delgado, G [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Villanueva, J A [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain)

    1994-04-01

    Meningovascular neurosyphilis (MN) is an unusual cause of stroke in young adults. The clinical manifestations include prodromal symptoms weeks or months before definitive stroke. The diagnosis is based on clinical findings and examination of the serum and cerebrospinal fluid. We report a case of MN with basilar artery irregularities demonstrated by magnetic resonance angiography. (orig.)

  13. Cryogenic Preamplifiers for Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Johansen, Daniel H.; Sanchez-Heredia, Juan D.; Petersen, Jan R.

    2018-01-01

    Pursuing the ultimate limit of detection in magnetic resonance imaging (MRI) requires cryogenics to decrease the thermal noise of the electronic circuits. As cryogenic coils for MRI are slowly emerging cryogenic preamplifiers are required to fully exploit their potential. A cryogenic preamplifier...

  14. Automated Segmentation of Cardiac Magnetic Resonance Images

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Nilsson, Jens Chr.; Grønning, Bjørn A.

    2001-01-01

    Magnetic resonance imaging (MRI) has been shown to be an accurate and precise technique to assess cardiac volumes and function in a non-invasive manner and is generally considered to be the current gold-standard for cardiac imaging [1]. Measurement of ventricular volumes, muscle mass and function...

  15. Magnetic resonance imaging of xanthomatous meningioma

    International Nuclear Information System (INIS)

    Katayama, Y.; Tsubokawa, T.; Tanaka, A.; Koshinaga, M.; Nemoto, N.

    1993-01-01

    A case of meningioma with extensive xanthomatous metaplasia occurring in the left frontal convexity of a 37-year-old woman is reported. The tumour was demonstrated as a hypodense mass with minimal enhancement on CT. Our findings suggest that magnetic resonance imaging may provide a clue to the diagnosis of meningiomas with extensive xanthomatous metaplasia when CT is less specific. (orig.)

  16. Evaluation of nuclear magnetic resonance spectroscopy variability

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Felipe Rodrigues; Salmon, Carlos Ernesto Garrido, E-mail: garrido@ffclrp.usp.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filisofia, Ciencias e Letras; Otaduy, Maria Concepcion Garcia [Universidade de Sao Paulo (FAMUS/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Departamento de Radiologia

    2014-11-01

    Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

  17. Vascular anatomy in angiography for magnetic resonance

    International Nuclear Information System (INIS)

    Charry Lopez, Marco Luciano; Rivera Gomez, Juan Enrique

    1998-01-01

    A review of basic anatomical concepts and main variants, as well as some anatomical anomalies of the central nervous system vascularity, these concepts are considered essential for the interpretation of magnetic resonance angiography with time-of-flight (TOF) and phase-contrast (PC) methods

  18. Magnetic resonance imaging in obstetric diagnosis.

    Science.gov (United States)

    Weinreb, J C; Lowe, T W; Santos-Ramos, R; Cunningham, F G; Parkey, R

    1985-01-01

    Five patients with abnormal pregnancies were examined with ultrasound (US) and magnetic resonance imaging (MR). Three had a malformed fetus, 1 had a molar pregnancy, and 1 had an ovarian mass. Both maternal and fetal structures were clearly shown, although fetal motion may have resulted in image degradation in some cases. The authors suggest that MR may be useful in obstetric diagnosis.

  19. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA is a noninvasive ... possibility that you’re pregnant tell your doctor as well. On the day of your exam, it’s ...

  20. Magnetic resonance imaging in sudden deafness

    International Nuclear Information System (INIS)

    Ramos, Hugo Valter Lisboa; Barros, Flavia Alencar; Penido, Norma de Oliveira; Souza, Ana Claudia Valerio de; Yamaoka, Wellington Yugo; Yamashita, Helio

    2005-01-01

    The etiology of sudden deafness can remain undetermined despite extensive investigation. This study addresses the value of magnetic resonance imaging in the analysis of sudden deafness patients.Study Design: transversal cohort.Material And Method: In a prospective study, 49 patients attended at otolaryngology emergency room of Federal University of Sao Paulo - Escola Paulista de Medicina, from April 2001 to May 2003, were submitted to magnetic resonance imaging.Results: Magnetic Resonance abnormalities were seen in 23 (46.9%) patients and revealed two tumors suggestive of meningioma, three vestibular schwannomas, thirteen microangiopathic changes of the brain and five (21.7%) pathological conditions of the labyrinth.Conclusion: Sudden deafness should be approached as a symptom common to different diseases. The presence of cerebellopontine angle tumors in 10.2% of our cases, among other treatable causes, justifies the recommendation of gadolinium-enhanced magnetic resonance use, not only to study the auditory peripheral pathway, but to study the whole auditory pathway including the brain. (author)

  1. Magnetic resonance studies of solid polymers

    International Nuclear Information System (INIS)

    Lenk, R.

    1969-01-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [fr

  2. Appropriateness of computed tomography and magnetic resonance ...

    African Journals Online (AJOL)

    Introduction. Computed tomography (CT) and magnetic resonance imaging (MRI) are an essential part of modern healthcare. Marked increases in clinical demand for these imaging modalities are straining healthcare expenditure and threatening health system sustainability. The number of CT and MRI scans requested in ...

  3. Magnetic resonance imaging of the knee

    International Nuclear Information System (INIS)

    Nederveen, D.; Bakker, C.J.G.; Scholten, F.G.; Feldberg, N.A.M.; Postma, J.H.; Vis, H. van der

    1989-01-01

    Sixteen patients suspected of having meniscal lesions, were examined bt magnetic resonance (MR) and arthroscopy, MR and arthroscopy corelate well for meniscal and cruciate ligament lesions. Damage of the articular cartilage was, however, not detected by MR (author). 15 refs.; 4 figs.; 1 tab

  4. Intralabyrinthine schwannoma shown by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Saeed, S.R.; Birzgalis, A.R.; Ramsden, R.T.

    1994-01-01

    Intralabyrinthine schwannomas are rare benign tumours which present with progressive or fluctuant audiovestibular symptoms and may mimic Menieres disease. The size and position of these lesions make preoperative diagnosis unusual and most are discovered incidentally at labyrinthectomy. A case is reported which was diagnosed on magnetic resonance imaging and confirmed at surgery. (orig.)

  5. Magnetic resonance imaging of semicircular canals.

    Science.gov (United States)

    Sbarbati, A; Leclercq, F; Zancanaro, C; Antonakis, K

    1992-01-01

    The present paper reports the results of the first investigation of the semicircular canals in a living, small animal by means of high spatial resolution magnetic resonance imaging. This procedure is noninvasive and allows identification of the endolymphatic and perilymphatic spaces yielding a morphology quite consistent with direct anatomical examination. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:1506290

  6. Quantitative dosing by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Solomon, I.

    1958-01-01

    The measurement of the absolute concentration of a heavy water reference containing approximately 99.8 per cent of D 2 O has been performed, by an original magnetic resonance method ('Adiabatic fast passage method') with a precision of 5.10 -5 on the D 2 O concentration. (author) [fr

  7. Magnetic resonance angiography in meningovascular syphilis

    International Nuclear Information System (INIS)

    Gallego, J.; Soriano, G.; Zubieta, J.L.; Delgado, G.; Villanueva, J.A.

    1994-01-01

    Meningovascular neurosyphilis (MN) is an unusual cause of stroke in young adults. The clinical manifestations include prodromal symptoms weeks or months before definitive stroke. The diagnosis is based on clinical findings and examination of the serum and cerebrospinal fluid. We report a case of MN with basilar artery irregularities demonstrated by magnetic resonance angiography. (orig.)

  8. Nonlinear nuclear magnetic resonance in ferromagnets

    International Nuclear Information System (INIS)

    Nurgaliev, T.

    1988-01-01

    The properties of nonlinear nuclear magnetic resonance (NMR) have been studied theoretically by taking into account the interaction between NMR and FMR in the ferromagnets. The Landau-Lifshitz-Bloch equations, describing the electron and nuclear magnetization behaviour in ferromagnets are presented in an integral form for a weakly excited electronic system. The stationary solution of these equations has been analysed in the case of equal NMR and FMR frequencies: the criteria for the appearance of two stable dynamic states is found and the high-frequency magnetic susceptibility for these systems is investigated. 2 figs., 8 refs

  9. The magnetic fields at the surface of active single G-K giants

    Science.gov (United States)

    Aurière, M.; Konstantinova-Antova, R.; Charbonnel, C.; Wade, G. A.; Tsvetkova, S.; Petit, P.; Dintrans, B.; Drake, N. A.; Decressin, T.; Lagarde, N.; Donati, J.-F.; Roudier, T.; Lignières, F.; Schröder, K.-P.; Landstreet, J. D.; Lèbre, A.; Weiss, W. W.; Zahn, J.-P.

    2015-02-01

    Aims: We investigate the magnetic field at the surface of 48 red giants selected as promising for detection of Stokes V Zeeman signatures in their spectral lines. In our sample, 24 stars are identified from the literature as presenting moderate to strong signs of magnetic activity. An additional 7 stars are identified as those in which thermohaline mixing appears not to have occured, which could be due to hosting a strong magnetic field. Finally, we observed 17 additional very bright stars which enable a sensitive search to be performed with the spectropolarimetric technique. Methods: We use the spectropolarimeters Narval and ESPaDOnS to detect circular polarization within the photospheric absorption lines of our targets. We treat the spectropolarimetric data using the least-squares deconvolution method to create high signal-to-noise ratio mean Stokes V profiles. We also measure the classical S-index activity indicator for the Ca ii H&K lines, and the stellar radial velocity. To infer the evolutionary status of our giants and to interpret our results, we use state-of-the-art stellar evolutionary models with predictions of convective turnover times. Results: We unambiguously detect magnetic fields via Zeeman signatures in 29 of the 48 red giants in our sample. Zeeman signatures are found in all but one of the 24 red giants exhibiting signs of activity, as well as 6 out of 17 bright giant stars. However no detections were obtained in the 7 thermohaline deviant giants. The majority of the magnetically detected giants are either in the first dredge up phase or at the beginning of core He burning, i.e. phases when the convective turnover time is at a maximum: this corresponds to a "magnetic strip" for red giants in the Hertzsprung-Russell diagram. A close study of the 16 giants with known rotational periods shows that the measured magnetic field strength is tightly correlated with the rotational properties, namely to the rotational period and to the Rossby number Ro

  10. Interaction of magnetic resonators studied by the magnetic field enhancement

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available It is the first time that the magnetic field enhancement (MFE is used to study the interaction of magnetic resonators (MRs, which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  11. Magnetic resonance study of maghemite-based magnetic fluid

    International Nuclear Information System (INIS)

    Figueiredo, L.C.; Lacava, B.M.; Skeff Neto, K.; Pelegrini, F.; Morais, P.C.

    2008-01-01

    This study reports on the magnetic resonance (MR) data (X-band experiment) of 10.2 nm average diameter maghemite nanoparticle in the temperature range of 100-230 K. Maghemite nanoparticles were suspended as low-pH ionic magnetic fluid containing 2.3x10 17 particles/cm 3 . The temperature dependence of both resonance linewidth and resonance field of the zero-field-cooled sample as well as the resonance field of the field-cooled sample (angular variation experiment) was analyzed using well-established methodology. Information regarding particle size, particle clusterization and surface magnetic anisotropy were obtained from the analysis of the MR data. The number of magnetic sites per particle from the MR data is in excellent agreement with the number provided by the transmission electron microscopy (TEM) data. The demagnetizing field value obtained from the MR data indicates cluster of particles containing on average 1.42 particles. The MR angular variation data suggest that magnetoelastic effect accounts for the non-linearity observed for the surface component of the magnetic anisotropy

  12. Magnetic resonance imaging of infectious myositis

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha [The Catholic Univ., College of Medicine, Suwon (Korea, Republic of)

    1998-09-01

    To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

  13. Magnetic resonance imaging of infectious myositis

    International Nuclear Information System (INIS)

    Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha

    1998-01-01

    To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

  14. Magnetic resonance: safety measures and biological effects

    International Nuclear Information System (INIS)

    Gordillo, I.; Lafuente, J.; Fernandez, C.; Barbero, M.J.; Cascon, E.

    1997-01-01

    The biological effects of electromagnetic fields is currently a subject of great controversy. For this reason, magnetic resonance imaging (MRI) and spectroscopy are constantly under investigation. The source of the risk in MRI is associated with the three types of electromagnetic radiation to which the patient is exposed: the static magnetic field, variable (gradient) magnetic fields and radiofrequency fields. Each is capable of producing significant biological effects when employed at sufficient intensity. Patients exposed to risk sources are those situated within the lines of force of the magnetic field, ellipsoid lines that are arranged around the magnet, representing the strength of the surrounding field. To date, at the intensity normally utilized in MRI(<2T) and respecting the field limit recommendations established by the US Food and Drug Administration (FDA) for clinical use of this technique no adverse secondary biological effects have been reported. The known biological effects and other possible secondary effects are reviewed, and the recommended safety measures are discussed. (Author)

  15. Magnetic resonance imaging of aneurysmal subarachnoid hemorrhage

    International Nuclear Information System (INIS)

    Ogawa, Toshihide; Shimosegawa, Eku; Inugami, Atsushi; Shishido, Fumio; Fujita, Hideaki; Ito, Hiroshi; Uemura, Kazuo; Yasui, Nobuyuki

    1991-01-01

    Magnetic resonance imaging of subarachnoid hemorrhage (SAH) due to aneurysm rupture was evaluated in relation to CT findings in nine patients. Six patients were studied within 3 days and the other three patients were studied 4 to 6 days from the ictus of SAH using a 0.5 Tesla superconducting unit. In all of the patients, hematoma in the subarachnoid space and ventricles was demonstrated by the proton density-weighted spin echo sequence, which showed that bloody cerebrospinal fluid (CSF) had a higher signal intensity than brain tissue or normal CSF. Magnetic resonance imaging was more sensitive in detecting SAH and more informative as to the site of the ruptured aneurysm than CT. Despite some limitations in applying it to patients with acute SAH, magnetic resonace imaging has clear advantages in the diagnosis of SAH. (author)

  16. The market for magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Carlson, L.

    1990-01-01

    The medical market is, at present, the most dominant market for low T c superconductors. Indeed, without magnetic resonance imaging (MRI), there would hardly be a low T c superconductor market at all. According to the author, any development that can expand the medical market for MRI machines would be a welcome one. This paper reports how the recent advances in magnetic resonance spectroscopy (MRS) are such a development. While the principle of MRS has bee around as long as MRI, only recently have advances in technique, computer programming and magnet technology allowed MRS to advance to a point where it may become an important technology-one that could increase the medical market for superconductors. The author discussed how MRS can be used to analyze oil core samples for their oil content, oil/water ratios, how the oil is bound and how to extract it

  17. Magnetic resonance imaging of aneurysmal subarachnoid hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Toshihide; Shimosegawa, Eku; Inugami, Atsushi; Shishido, Fumio; Fujita, Hideaki; Ito, Hiroshi; Uemura, Kazuo; Yasui, Nobuyuki (Research Inst. of Brain and Blood Vessels, Akita (Japan))

    1991-11-01

    Magnetic resonance imaging of subarachnoid hemorrhage (SAH) due to aneurysm rupture was evaluated in relation to CT findings in nine patients. Six patients were studied within 3 days and the other three patients were studied 4 to 6 days from the ictus of SAH using a 0.5 Tesla superconducting unit. In all of the patients, hematoma in the subarachnoid space and ventricles was demonstrated by the proton density-weighted spin echo sequence, which showed that bloody cerebrospinal fluid (CSF) had a higher signal intensity than brain tissue or normal CSF. Magnetic resonance imaging was more sensitive in detecting SAH and more informative as to the site of the ruptured aneurysm than CT. Despite some limitations in applying it to patients with acute SAH, magnetic resonace imaging has clear advantages in the diagnosis of SAH. (author).

  18. Transcranial magnetic stimulation assisted by neuronavigation of magnetic resonance images

    Science.gov (United States)

    Viesca, N. Angeline; Alcauter, S. Sarael; Barrios, A. Fernando; González, O. Jorge J.; Márquez, F. Jorge A.

    2012-10-01

    Technological advance has improved the way scientists and doctors can learn about the brain and treat different disorders. A non-invasive method used for this is Transcranial Magnetic Stimulation (TMS) based on neuron excitation by electromagnetic induction. Combining this method with functional Magnetic Resonance Images (fMRI), it is intended to improve the localization technique of cortical brain structures by designing an extracranial localization system, based on Alcauter et al. work.

  19. Magnetic resonance imaging in otolaryngology

    International Nuclear Information System (INIS)

    Gradzki, J.; Paprzycki, W.

    1993-01-01

    In the paper authors describe fundamental physical properties of a phenomenon of the radio-frequency excitation and relaxation of nuclei ordered in a strong magnetic field and the usefulness of MRI in medical diagnostic procedures. Basic interpretations principles of MR imaging due to signal intensity differences between organs and tissues in T 1 - and T 2 - weighted sequences and proton density are presented. Both, literature review and experience of authors suggest application of MRI in otolaryngology, it is illustrated by a lot of examples. The MR imaging studies were compared with results obtained from CT in otolaryngology field. (author)

  20. Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Lumbar Spine What's in this article? ...

  1. Magnetic resonance imaging by using nano-magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Shokrollahi, H., E-mail: Shokrollahi@sutech.ac.ir [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Khorramdin, A. [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Isapour, Gh. [Department of Materials and Engineering, Hakim Sabzevari University (Iran, Islamic Republic of)

    2014-11-15

    Magnetism and magnetic materials play a major role in various biological applications, such as magnetic bioseparation, magnetic resonance imaging (MRI), hyperthermia treatment of cancer and drug delivery. Among these techniques, MRI is a powerful method not only for diagnostic radiology but also for therapeutic medicine that utilizes a magnetic field and radio waves. Recently, this technique has contributed greatly to the promotion of the human quality life. Thus, this paper presents a short review of the physical principles and recent advances of MRI, as well as providing a summary of the synthesis methods and properties of contrast agents, like different core materials and surfactants. - Highlights: • This paper studies the physics of MRI as a powerful diagnostic technique. • MRI uses the differentiation between healthy and pathological tissues. • The relaxation times can be shortened by the use of a magnetic contrast agent. • The magnetic nanoparticles act as contrast agents, helping to increase the resolution. • Different synthesis methods can influence the magnetic resonance behavior.

  2. Musculoskeletal applications of magnetic resonance imaging: Council on Scientific Affairs

    International Nuclear Information System (INIS)

    Harms, S.E.; Fisher, C.F.; Fulmer, J.M.

    1989-01-01

    Magnetic resonance imaging provides superior contrast, resolution, and multiplanar imaging capability, allowing excellent definition of soft-tissue and bone marrow abnormalities. For these reasons, magnetic resonance imaging has become a major diagnostic imaging method for the evaluation of many musculoskeletal disorders. The applications of magnetic resonance imaging for musculoskeletal diagnosis are summarized and examples of common clinical situations are given. General guidelines are suggested for the musculoskeletal applications of magnetic resonance imaging

  3. Nuclear magnetic resonance (NMR): principles and applications

    International Nuclear Information System (INIS)

    Quibilan, E.I.

    The basis for the phenomenon of nuclear magnetic resonance (NMR) is the ability of certain nuclei possessing both intrinsic angular momentum or ''spin'' I and magnetic moment to absorb electromagnetic energy in the radio frequency range. In principle, there are approximately 200 nuclei which may be investigated using the NMR technique. The NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum provides a variety of qualitative and quantitative analytical applications. The most obvious applications consist of the measurements of nuclear properties, such as spin number and nuclear magnetic moment. In liquids, the fine structure of resonance spectra provides a tool for chemical identification and molecular structure analysis. Other applications include the measurements of self-diffusion coefficients, magnetic fields and field homogeneity, inter-nuclear distances, and, in some cases, the water content of biological materials. (author)

  4. Physics of Magnetic Resonance. Chapter 14

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hee Kwon [Hospital of the University of Pennsylvania, Philadelphia (United States)

    2014-09-15

    The discovery of nuclear magnetic resonance (NMR), a property of nuclei in a magnetic field where they are able to absorb applied radiofrequency (RF) energy and subsequently release it at a specific frequency, goes back many decades to the early 1900s. Physicist Isidor I. Rabi, fascinated by the work of Otto Stern and Walther Gerlach which demonstrated that particles have intrinsic quantum properties, delved into the magnetic properties of nuclei, and in 1938 Rabi discovered the phenomenon of NMR. Several years later, in 1946, Felix Bloch and Edward Purcell refined the methods and successfully measured the NMR signal from liquids and solids. For their discoveries, Rabi received the Nobel Prize for physics in 1944 and Bloch and Purcell in 1952. While Rabi, Bloch, Purcell and other physicists working in this field had laid the foundations, a major discovery that transformed the NMR phenomenon for imaging was not made until 1973, when Paul Lauterbur developed a method for spatially encoding the NMR signal by utilizing linear magnetic field gradients. About the same time, Peter Mansfield had also discovered a means of determining the spatial structure of solids by introducing a linear gradient across the object. The idea of applying magnetic field gradients to induce spatially varying resonance frequencies to resolve the spatial distribution of magnetization was a major milestone and the beginning of magnetic resonance imaging (MRI). For their work, Lauterbur and Mansfield were awarded the Nobel Prize for medicine in 2003. Since its discovery, MRI has quickly become one of the most important medical imaging devices available to physicians today. Unlike other imaging modalities, such as X ray and computed tomography, MRI does not involve ionizing radiation. MRI also offers superior soft tissue contrast that is not possible with other imaging modalities. Furthermore, in MRI, the desired level of image contrast among different tissues can often be precisely controlled

  5. 76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

    Science.gov (United States)

    2011-09-20

    ...] Magnetic Resonance Imaging Safety; Public Workshop AGENCY: Food and Drug Administration, HHS. ACTION... announcing a public workshop entitled: ``Magnetic Resonance Imaging (MRI) Safety Public Workshop.'' The purpose of the public workshop is to discuss factors affecting the safe use of magnetic resonance imaging...

  6. Functional magnetic resonance imaging of the primary motor cortex ...

    Indian Academy of Sciences (India)

    Unknown

    Abbreviations used: BOLD, Blood oxygenation level dependent; CBF, cerebral blood flow; fMRI, functional magnetic resonance imaging; EPI, eco-planar imaging; FOV, field of view; MRI, Magnetic resonance imaging; MRS, magnetic resonance spectroscopy;. PET, position emission tomography; rCBF, regional cerebral ...

  7. Nuclear magnetic resonance in ferromagnetic terbium metal

    International Nuclear Information System (INIS)

    Cha, C.L.T.

    1974-01-01

    The magnetic properties of terbium were studied by the method of zero field nuclear magnetic resonance at 1.5 to 4 and 85 to 160 0 K. Two unconventional experimental techniques have been employed: the swept frequency and the swept temperature technique. Near 4 0 K, triplet resonance line structures were found and interpreted in terms of the magnetic domain and wall structures of ferromagnetic terbium. In the higher temperature range, temperature dependence of the resonance frequency and the quadrupole splitting were measured. The former provides a measurement of the temperature dependence of the magnetization M, and it agrees with bulk M measurements as well as the latest spin wave theory of M(T) (Brooks 1968). The latter agrees well with a calculation using a very general single ion density matrix for collective excitations (Callen and Shtrikman 1965). In addition, the small temperature-independent contribution to the electric field gradient at the nucleus due to the lattice and conduction electrons was untangled from the P(T) data. Also an anomalous and unexplained relaxation phenomenon was also observed

  8. Two-phonon giant resonances in 136Xe, 208Pb, and 238U

    International Nuclear Information System (INIS)

    Boretzky, K.; Gruenschloss, A.; Ilievski, S.; Adrich, P.; Aumann, T.; Bertulani, C.A.; Cub, J.; Dostal, W.; Eberlein, B.; Elze, T.W.; Emling, H.; Fallot, M.; Holeczek, J.; Holzmann, R.; Kozhuharov, C.; Kratz, J.V.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Lubkiewicz, E.; Mordechai, S.; Ohtsuki, T.; Reiter, P.; Simon, H.; Stelzer, K.; Stroth, J.; Suemmerer, K.; Surowiec, A.; Wajda, E.; Walus, W.

    2003-07-01

    The excitation of the double-phonon giant dipole resonance was observed in heavy projectile nuclei impinging on targets of high nuclear charge with energies of 500-700 MeV/nucleon. New experimental data are presented for 136 Xe and 238 U together with further analysis of earlier data on 208 Pb. Differential cross sections dσ/dE * and dσ/dθ for electromagnetic excitations were deduced. Depending on the isotope, cross sections appear to be enhanced in comparison to those expected from a purely harmonic nuclear dipole response. The cumulative effect of excitations of two-phonon states composed of one dipole and one quadrupole phonon, of predicted anharmoniticies in the double-phonon dipole response, and of damping of the dipole resonance during the collision may account for the discrepancy. In addition, decay properties of two-phonon resonances were studied and compared to that of a statistical decay. (orig.)

  9. Giant resonance phenomena in the electron impact ionization of heavy atoms and ions

    International Nuclear Information System (INIS)

    Younger, S.M.

    1986-01-01

    Heavy atoms and ions offer an interesting opportunity to study atomic physics in a region where the atomic structure is dominated by the interelectronic interactions. One illustration of this is the profound term dependence of atomic orbitals for certain configurations of heavy atoms and ions. The appearance of giant scattering resonances in the cross sections for ionization of heavy atoms by electron impact is a manifestation of resonance behavior. Such resonant structures arise from the double well nature of the scattering potential and have recently been identified in the cross sections for the electron impact ionization of several xenon-like ions. The results of calculations showing effects for a variety of other ions are summarized. 7 refs., 4 figs

  10. [Magnetic resonance compatibility research for coronary mental stents].

    Science.gov (United States)

    Wang, Ying; Liu, Li; Wang, Shuo; Shang, Ruyao; Wang, Chunren

    2015-01-01

    The objective of this article is to research magnetic resonance compatibility for coronary mental stents, and to evaluate the magnetic resonance compatibility based on laboratory testing results. Coronary stents magnetic resonance compatibility test includes magnetically induced displacement force test, magnetically induced torque test, radio frequency induced heating and evaluation of MR image. By magnetic displacement force and torque values, temperature, and image distortion values to determine metal coronary stent demagnetization effect. The methods can be applied to test magnetic resonance compatibility for coronary mental stents and evaluate its demagnetization effect.

  11. A hyperpolarized equilibrium for magnetic resonance.

    Science.gov (United States)

    Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B; Mewis, Ryan E; Highton, Louise A R; Kenny, Stephen M; Green, Gary G R; Leibfritz, Dieter; Korvink, Jan G; Hennig, Jürgen; von Elverfeldt, Dominik

    2013-01-01

    Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all ¹H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10⁻³ Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.

  12. Nuclear magnetic resonance imaging in pharmaceutical research

    International Nuclear Information System (INIS)

    Sarkar, S.K.

    1991-01-01

    Nuclear magnetic resonance imaging has important applications in pharmaceutical research since it allows specific tissue and disease characterization in animal models noninvasively with excellent anatomical resolution and therefore provides improved ability to monitor the efficacy of novel drugs. The utility of NMR imaging in renal studies to monitor the mechanism of drug action and renal function in rats is described. The extension of the resolution of an NMR image to microscopic domain at higher magnetic field strengths and the utility of NMR microimaging in cerebrovascular and tumour metastasis studies in mice are discussed. (author). 40 refs., 14 figs

  13. Nuclear magnetic resonance method and apparatus

    International Nuclear Information System (INIS)

    Young, I.R.

    1983-01-01

    In a method of investigating the distribution of a quantity in a chosen region of a body (E) by nuclear magnetic resonance techniques movement of the body during the investigation is monitored by probes (A, B C) (C extends orthogonally to A and B) attached to the body and responsive to magnetic fields applied to the body during the investigation. An apparatus for carrying out the method is also described. If movement is detected, due compensation may be made during processing of the collected data, or the latter may be re-ascertained after appropriate adjustment e.g. a change in the RF excitation frequency. (author)

  14. Proton magnetic resonance spectroscopy in the fetus.

    Science.gov (United States)

    Story, Lisa; Damodaram, Mellisa S; Allsop, Joanna M; McGuinness, Amy; Wylezinska, Marzena; Kumar, Sailesh; Rutherford, Mary A

    2011-09-01

    Magnetic Resonance Imaging (MRI) has become an established technique in fetal medicine, providing complementary information to ultrasound in studies of the brain. MRI can provide detailed structural information irrespective of the position of the fetal head or maternal habitus. Proton Magnetic Resonance Spectroscopy ((1)HMRS) is based on the same physical principles as MRI but data are collected as a spectrum, allowing the biochemical and metabolic status of in vivo tissue to be studied in a non-invasive manner. (1)HMRS has been used to assess metabolic function in the neonatal brain but fetal studies have been limited, primarily due to fetal motion. This review will assess the technique and findings from fetal studies to date. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  15. Magnetic resonance studies of intercalation compounds

    International Nuclear Information System (INIS)

    Miller, G.R.

    1990-01-01

    During the last three or four years, nearly tow hundred papers have been published that used NMR or ESR spectroscopy to study compounds formed by the intercalation of molecules or ions into the van der Waals gap of a layered hast compound. The host lattices have ranged from the simple, such as graphite, to the complex, such as clay. In many cases, magnetic resonance techniques now enable one to obtain quite detailed information on even fairly complex intercalated species, on the nature of the changes in the host lattice accompanying intercalation, and on the nature of the interactions between the intercalant species and the host lattice. Magnetic resonance is used in conunction with many other techniques to obtain a fuller picture of these interesting systems, but this review will limit its focus to the use of NMR and ESR techniques. (author). 51 refs

  16. Sensorineural hearing loss after magnetic resonance imaging

    DEFF Research Database (Denmark)

    Mollasadeghi, Abolfazl; Mehrparvar, Amir Houshang; Atighechi, Saeid

    2013-01-01

    Magnetic resonance imaging (MRI) devices produce noise, which may affect patient's or operators' hearing. Some cases of hearing impairment after MRI procedure have been reported with different patterns (temporary or permanent, unilateral or bilateral, with or without other symptoms like tinnitus)......). In this report, a case of bilateral sensorineural hearing loss in an otherwise healthy patient underwent brain MRI was described. The patient's hearing loss was accompanied with tinnitus and was not improved after 3 months of followup.......Magnetic resonance imaging (MRI) devices produce noise, which may affect patient's or operators' hearing. Some cases of hearing impairment after MRI procedure have been reported with different patterns (temporary or permanent, unilateral or bilateral, with or without other symptoms like tinnitus...

  17. Magnetic resonance imaging findings in tuberculous meningoencephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Pui, M.H.; Memon, W.A. [Aga Khan Univ. Hospital, Dept. of Radiology, Karachi (Pakistan)

    2001-02-01

    To evaluate the efficacy of magnetic resonance imaging (MRI) for distinguishing tuberculosis from other types of meningoencephalitis. MRIs of 100 patients with tuberculous (50), pyogenic (33), viral (14), or fungal (3) meningoencephalitis were analyzed independently by 2 radiologists. Number, size, location, signal characteristics, surrounding edema, and contrast enhancement pattern of nodular lesions; location and pattern of meningeal enhancement; extent of infarct or encephalitis and hydrocephalus were evaluated. Contrast-enhancing nodular lesions were detected in patients with tuberculous (43 of 50 patients), pyogenic (9 of 33), and fungal (3 of 3) infections. No nodules were detected in patients with viral meningoencephalitis. Using the criteria of 1 or more solid rim or homogeneously enhancing nodules smaller than 2 cm, the sensitivity, specificity and accuracy for diagnosing tuberculous meningitis were 86.0%, 90.0% and 88.0%, respectively. Magnetic resonance imaging is useful in distinguishing tuberculous from pyogenic, viral and fungal meningoencephalitis. (author)

  18. Survey of the (3He,t) reaction: Excitation of the isobaric analog of the giant dipole resonance

    International Nuclear Information System (INIS)

    Tabor, S.L.; Chang, C.C.; Collins, M.T.; Wagner, G.J.; Wu, J.R.; Halderson, D.W.; Petrovich, F.

    1982-01-01

    The ( 3 He,t) reaction at 130 and 170 MeV has been investigated on targets of 12 C, 16 O, 27 Al, 28 Si, 40 Ca, 46 Ti, and 90 Zr. Data for the ( 3 He, 3 He') reaction were measured simultaneously for reference purposes. Structure is observed in the spectra from the ( 3 He, 3 He') and ( 3 He,t) reaction at the expected positions of the giant quadrupole resonance and the isobaric analog of the giant dipole resonance, respectively. An angular distribution was measured for the suspected giant dipole resonance structure in the 40 Ca( 3 He,t) 40 Sc reaction at 130 MeV. The data are reasonably described by a collective model calculation based on the Goldhaber-Teller model for the giant dipole resonance. Several other strong peaks at excitation energies below the giant dipole resonance are observed in the ( 3 He,t) spectra. Most notable of these are the ones at the expected positions for analogs of well known 1 + states and 1hω stretched states in the targets

  19. Two-dimensional nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Bax, A.; Lerner, L.

    1986-01-01

    Great spectral simplification can be obtained by spreading the conventional one-dimensional nuclear magnetic resonance (NMR) spectrum in two independent frequency dimensions. This so-called two-dimensional NMR spectroscopy removes spectral overlap, facilitates spectral assignment, and provides a wealth of additional information. For example, conformational information related to interproton distances is available from resonance intensities in certain types of two-dimensional experiments. Another method generates 1 H NMR spectra of a preselected fragment of the molecule, suppressing resonances from other regions and greatly simplifying spectral appearance. Two-dimensional NMR spectroscopy can also be applied to the study of 13 C and 15 N, not only providing valuable connectivity information but also improving sensitivity of 13 C and 15 N detection by up to two orders of magnitude. 45 references, 10 figures

  20. Nuclear magnetic resonance - from molecules to man

    OpenAIRE

    Wüthrich, Kurt

    2017-01-01

    Initial observations of the physical phenomenon of nuclear magnetic resonance (NMR) date back to the late 1940s. In the following two decades high-resolution NMR in solution became an indispensible analytical tool in chemistry, and solid state NMR had an increasingly important role in physics. Some of the potentialities of the method for investigations of complex biological systems had also long been anticipated, and initial experiments with biological specimens were described already 30 year...