WorldWideScience

Sample records for deformed rare-earth nuclei

  1. The decay from the two-quasiparticle regime in even-even deformed rare earth nuclei

    International Nuclear Information System (INIS)

    Henriques, A.; Thorstensen, T.F.; Hammaren, E.

    1983-06-01

    A bump at 1 MeV has been identified in coincidence gamma-ray spectra from the ( 3 He, 4 He) reaction in deformed rare earth nuclei. Particle/gamma-ray angular correlation indicates a dipole character. It is suggested that this bump corresponds to transitions from two-quasiparticle states to the ground state band

  2. Role of shape and quadrupole deformation of parents in the cluster emission of rare earth nuclei

    International Nuclear Information System (INIS)

    Girija, K.K.; Joseph, Antony

    2014-01-01

    The nuclear structure effects on α decay and cluster emission are investigated in the case of even–even rare earth nuclei 150–160 Dy, 150–160 Er, 150–160 Yb, 158,162,166–176 Hf, 160,164–178 W and 162,166,170–180 Os. The role of shape and deformation of parent nuclei in the decay rate is studied by taking the Coulomb and proximity potentials as the interacting barrier for the post scission configuration. The quadrupole deformation of parent nuclei causes a slight change in the half-life of α emissions, but it affects the rate of heavy cluster emissions significantly. Prolate deformation of parents enhances cluster emission, while an oblate deformation slows down the decay. Shape and deformation of parent nuclei causes change in the branching ratio also. A prolate deformation increases the branching ratio, whereas an oblate deformation reduces it. Highest branching ratio is predicted at N ∼ 90. (author)

  3. Rare-earth nuclei: Radii, isotope-shifts and deformation properties in the relativistic mean-field theory

    International Nuclear Information System (INIS)

    Lalazissis, G.A.; Ring, P.

    1996-01-01

    A systematic study of the ground-state properties of even-even rare earth nuclei has been performed in the framework of the Relativistic Mean-Field (RMF) theory using the parameter set NL-SH. Nuclear radii, isotope shifts and deformation properties of the heavier rare-earth nuclei have been obtained, which encompass atomic numbers ranging from Z=60 to Z=70 and include a large range of isospin. It is shown that RMF theory is able to provide a good and comprehensive description of the empirical binding energies of the isotopic chains. At the same time the quadrupole deformations β 2 obtained in the RMF theory are found to be in good agreement with the available empirical values. The theory predicts a shape transition from prolate to oblate for nuclei at neutron number N=78 in all the chains. A further addition of neutrons up to the magic number 82 brings about the spherical shape. For nuclei above N=82, the RMF theory predicts the well-known onset of prolate deformation at about N=88, which saturates at about N=102. The deformation properties display an identical behaviour for all the nuclear chains. A good description of the above deformation transitions in the RMF theory in all the isotopic chains leads to a successful reproduction of the anomalous behaviour of the empirical isotopic shifts of the rare-earth nuclei. The RMF theory exhibits a remarkable success in providing a unified and microscopic description of various empirical data. (orig.)

  4. Calculation of ground state deformation of even-even rare-earth nuclei in sdg interacting boson model

    International Nuclear Information System (INIS)

    Wang Baolin

    1995-01-01

    The analytical calculation of the nuclear ground state deformation of the even-even isotopes in the rare-earth region is given by utilizing the intrinsic states of the sdg interacting boson model. It is compared systematically with the reported theoretical and experimental results. It is shown that the sdg interacting boson model is a reasonable scheme for the description of even-even nuclei deformation

  5. Equilibrium deformations of single-particle states of odd nuclei of rare earth region

    International Nuclear Information System (INIS)

    Alikov, B.A.; Tsoj, E.G.; Zuber, K.; Pashkevich, V.V.

    1983-01-01

    In terms of the Strutinsky shell-correction method using the Woods-Saxon non-spherical potential the energies, quadrupole, and hexadecapole momenta of the ground and excited states of odd-proton nuclei with 61 6 deformation on atomic nuclei non-rotation states energies is discussed. It is shown that account of deformation of α 6 type slightly influences on the quadrupole and hexadecapole deformation value

  6. Calculating Absolute Transition Probabilities for Deformed Nuclei in the Rare-Earth Region

    Science.gov (United States)

    Stratman, Anne; Casarella, Clark; Aprahamian, Ani

    2017-09-01

    Absolute transition probabilities are the cornerstone of understanding nuclear structure physics in comparison to nuclear models. We have developed a code to calculate absolute transition probabilities from measured lifetimes, using a Python script and a Mathematica notebook. Both of these methods take pertinent quantities such as the lifetime of a given state, the energy and intensity of the emitted gamma ray, and the multipolarities of the transitions to calculate the appropriate B(E1), B(E2), B(M1) or in general, any B(σλ) values. The program allows for the inclusion of mixing ratios of different multipolarities and the electron conversion of gamma-rays to correct for their intensities, and yields results in absolute units or results normalized to Weisskopf units. The code has been tested against available data in a wide range of nuclei from the rare earth region (28 in total), including 146-154Sm, 154-160Gd, 158-164Dy, 162-170Er, 168-176Yb, and 174-182Hf. It will be available from the Notre Dame Nuclear Science Laboratory webpage for use by the community. This work was supported by the University of Notre Dame College of Science, and by the National Science Foundation, under Contract PHY-1419765.

  7. Underlying physics of identical odd- and even-mass bands in normally deformed rare-earth nuclei

    International Nuclear Information System (INIS)

    Yu Lei; Liu Shuxin; Lei Yian; Zeng Jinyan

    2001-01-01

    The microscopic mechanism of the identical odd- and even-mass number nuclear bands in normally deformed rare-earth nuclei was investigated using the particle-number conserving (PNC) method for treating nuclear pairing correlation. It was found that the odd particle of an odd-A identical band always occupied a cranked low j and high Ω Nilsson orbital (e.g. proton [404]7/2, [402]5/2. On the contrary, if the odd particle occupies an intruder high j orbital (e.g. neutron [633]7/2, proton[514]9/2), the moment of inertia of the odd-A band was much larger than that of neighboring even-even ground state band. The observed variation of moment of inertia (below band crossing) was reproduced quite well by the PNC calculation, in which no free parameter was involved. The strengths of monopole and Y 20 quadrupole interactions were determined by the experimental odd-even differences in binding energy and band head moment of inertia

  8. A special type of neutron-proton pairing interaction and the moments of inertia of some deformed even-even nuclei in the rare earth region

    International Nuclear Information System (INIS)

    Meftunoglu, E.; Gerceklioglu, M.; Erbil, H.H.; Kuliev, A.A.

    1998-01-01

    In this work, the effect of a special type of neutron-proton pairing interaction on the moments of inertia of some deformed nuclei in the rare earth region is investigated. First, making a perturbative approximation, we assume that the form of the equations of the BCS theory and usual Bogolyubov transformations are unchanged. Second, we use a phenomenological method for the strength of this neutron-proton pairing interaction introducing a parameter. Calculations show that this interaction is important for the ground-state moments of inertia and that it could be effectual in other nuclear phenomena. (author)

  9. Low-spin identical bands in rare earth nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Winchell, D.F.; Garrett, J.D.; Smith, A.

    1992-01-01

    A comprehensive study of odd-A rotational bands in normally deformed rare earth nuclei indicates that a large number of seniority-one configurations (21% for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models of nuclear pair correlation, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority

  10. Shell model Monte Carlo investigation of rare earth nuclei

    International Nuclear Information System (INIS)

    White, J. A.; Koonin, S. E.; Dean, D. J.

    2000-01-01

    We utilize the shell model Monte Carlo method to study the structure of rare earth nuclei. This work demonstrates the first systematic full oscillator shell with intruder calculations in such heavy nuclei. Exact solutions of a pairing plus quadrupole Hamiltonian are compared with the static path approximation in several dysprosium isotopes from A=152 to 162, including the odd mass A=153. Some comparisons are also made with Hartree-Fock-Bogoliubov results from Baranger and Kumar. Basic properties of these nuclei at various temperatures and spin are explored. These include energy, deformation, moments of inertia, pairing channel strengths, band crossing, and evolution of shell model occupation numbers. Exact level densities are also calculated and, in the case of 162 Dy, compared with experimental data. (c) 2000 The American Physical Society

  11. Anomalies in photofission of rare earth nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Gann, A.V.; Nazarova, T.S.; Noga, V.I.; Ranyuk, Y.N.; Sorokin, P.V.; Telegin, Y.N.

    1979-09-01

    Measurements of photofission produced by 1-GeV bremsstrahlung in the heavy rare earth elements show an anomalously large cross section compared to that predicted by the liquid drop model. These measurements check the results obtained previously with 1-GeV protons by Andronenko et al. (JETP Lett. 24, 573 (1976)).

  12. Allowed unhindered beta connected states in rare earth nuclei

    International Nuclear Information System (INIS)

    Sood, P.C.; Ray, R.S.

    1986-03-01

    The beta-connected states in odd-mass as well as even mass rare earth nuclei, where the transition is of allowed unhindered nature, are listed. The tabulation includes 54 cases of such transitions. Validity of Alaga selection rules is examined and the results are used to assign configurations to the involved single particle and two-particle states. (author)

  13. Level density and thermal properties in rare earth nuclei

    International Nuclear Information System (INIS)

    Siem, S.; Schiller, A.; Guttormsen, M.; Hjorth-Jensen, M.; Melby, E.; Rekstad, J.

    2000-01-01

    The level density at low spin has been extracted for several nuclei in the rare earth region using the ( 3 He,α) reaction. Within the framework of the microcanonical ensemble, the entropy and the temperature of the nuclei are derived. The temperature curve shows bumps which are associated with the break up of Cooper pairs. The entropies of the even-even and even-odd nuclei have been compared. The nuclear heat capacity is deduced within the framework of the canonical ensemble and exhibits an S-formed shape as function of temperature. (author)

  14. β4 systematics in rare-earth and actinide nuclei: sdg interacting boson model description

    International Nuclear Information System (INIS)

    Devi, Y.D.; Kota, V.K.B.

    1992-01-01

    The observed variation of hexadecupole deformation parameter β 4 with mass number A in rare-earth and actinide nuclei is studied in the sdg interacting boson model (IBM) using single j-shell Otsuka-Arima-Iachello mapped and IBM-2 to IBM-1 projected hexadecupole transition operator together with SU sdg (3) and SU sdg (5) coherent states. The SU sdg (3) limit is found to provide a good description of data

  15. Signature effects in 2qp bands of doubly even rare-earth nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kalra, Kawalpreet [Amity University, AUUP, Department of Physics, Amity Institute of Applied Sciences (AIAS), Noida (India); Goel, Alpana [Amity University, AUUP, Amity Institute of Nuclear Science and Technology (AINST), Noida (India); Jain, A.K. [Indian Institute of Technology (IIT), Department of Physics, Roorkee (India)

    2016-12-15

    The two-quasiparticle rotational bands in deformed doubly even nuclei in the rare-earth region have been studied in detail. A number of interesting features like odd-even staggering and signature inversion have been observed. The phenomenon of signature inversion/reversal is observed experimentally in {sup 162}{sub 66}Dy, {sup 170}{sub 70}Yb and {sup 170}{sub 74}W in even-even nuclei. Two quasiparticle plus rotor model (TQPRM) calculations are carried out to explain the reverse pattern of signature in {sup 170}{sub 74}W for the rotational band having configuration {(h_1_1_/_2)_p x (d_5_/_2)_p}. (orig.)

  16. Description of highly perturbed bands in rare earth nuclei

    International Nuclear Information System (INIS)

    Joshi, P.C.; Sood, P.C.

    1976-01-01

    Recently some highly perturbed positive parity bands have been populated in odd-mass rare earth nuclei. The energy spacings and sometimes even the spin sequences are drastically different from the usual strong coupling rotational model picture. The levels belonging to 'odd and even' I+1/2 are found to make separate groupings. The levels belonging to odd values of I+1/2 are seen to be very much favoured in comparison to the levels for which I+1/2 is even. In some cases only the favoured levels have been identified. These bands have been studied in the frame-work of rotation aligned coupling scheme in which the odd neutron in the unique parity orbital (in this case the isub(13/2) orbital) is strongly decoupled from the body fixed symmetry axis by the Coriolis force so as to make the projection of its angular momentum α on the rotation axis approximately a good quantum number. A description of the energy levels is suggested by assigning the quantum number α-j to the favoured levels and α-j-1 to the unfavoured levels. The intraband transitions of the favoured and unfavoured bands are examined in comparison with those in the adjacent ground state bands in even-even nuclei. (author)

  17. The neutron-proton pairing and the moments of inertia of the rare earth even-even nuclei

    International Nuclear Information System (INIS)

    Calik, A. E.; Deniz, C.; Gerceklioglu, M.

    2009-01-01

    In this study, the possible effect of the neutron-proton pairing interaction in the heavy nuclei has been investigated in the framework of the BCS model by making a simple approximation. This effect has been searched realistically by calculating the moments of inertia of deformed even-even nuclei. Calculations show that the moments of inertia of rare earth nuclei changed dramatically and approached the experimental values.

  18. Shapes and alignments at high spin in some rare-earth nuclei

    International Nuclear Information System (INIS)

    Deleplanque, M.A.; Diamond, R.M.; Stephens, F.S.; Macchiavelli, A.O.; Doessing, T.; Draper, J.E.; Dines, E.L.

    1985-01-01

    The structure of nuclei at high spins is dominated by an interplay between deformation and alignment effects. Cranking models predict various shapes but at the highest spins, there is a tendency towards large triaxial deformations and sometimes towards very large prolate deformations (superdeformations). Directly involved in the shape changes are aligned orbitals which come down to the Fermi level as the nucleus rotates more rapidly. At a certain frequency, they become populated and cause large alignments. The mechanism of these changes has been explored by looking at a series of rare earth quasirotational nuclei from Dy to W in the transition region around N = 90 neutrons. The continuum spectra, corrected for incomplete population (feeding) of the high spins, are directly proportional to dynamic effective moments of inertia which describe how much spin is generated at each rotational frequency

  19. Effective neutron-proton interaction in rare earth odd-odd nuclei

    International Nuclear Information System (INIS)

    Boisson, Jean-Paul.

    1975-01-01

    The effective neutron-proton interaction V(np) in the rare earth odd-odd deformed nuclei is studied. The parameters of the effective interaction are determined from least square fits of calculated matrix elements compared to the ones extracted from experiment. These fits show the existence of a long range repulsive component as well the importance of the even term of the tensor part of V(np). Some informations are obtained concerning the influence of the choice of the sample of experimental data, of the average field and finally, of the radial shape of the effective interaction. Some predictions are made concerning as yet unconfirmed V(np) matrix elements [fr

  20. Study on decay of rare earth nuclei produced by fission

    Energy Technology Data Exchange (ETDEWEB)

    Kawade, Kiyoshi; Yamamoto, Hiroshi; Shibata, Michihiro; Asai, Masato [Nagoya Univ. (Japan); Tsukada, Kazuaki; Osa, Akihiko; Shinohara, Nobuo; Iimura, Hideki

    1996-01-01

    JAERI-ISOL utilizes charge particle induced fission by proton and heavy proton produced by the tandem type accelerator (JAERI). To study the decay mechanism and nuclei structure of neutron and excess nuclei produced by actinoid fission, JAERI-ISOL was improved by developing the multilayer target tank. So that, the intensity of mass separated ion beam increased enough to use. New 76.6 KeV {gamma}-ray with about 10s of half life was found in the preliminary experiment. (S.Y.)

  1. Low lying electric dipole excitations in nuclei of the rare earth region

    International Nuclear Information System (INIS)

    von Brentano, P.; Zilges, A.; Herzberg, R.D.; Kneissl, U.; Heil, R.D.; Pitz, H.H.; Wesselborg, C.

    1992-01-01

    From many experiments with low energy photon scattering on deformed rare earth nuclei we have obtained detailed information about the distribution of electric dipole strength below 4 MeV. Apart from some weaker transitions between 2 and 4 MeV we observed one, and sometimes two, very strong El-groundstate transitions around 1.5 MeV in all examined nuclei. They arise from the de-excitation of the bandheads of the (J π ,K)=(l - ,0) and (J π ,K)=(l - ,1) octupole vibrational bands. It is shown that the decay branching ratios and the absolute transition strengths of these states can be reproduced rather well with an improved T(El)-operator in the sdf-Interacting Boson Model. Another class of octupole states has been investigated in the region of the semimagic nucleus 142 Nd. Here a quintuplet of collective excitations around 3.5 MeV is expected due to the coupling of the 3--octupole vibration with the 2+-quadrupole vibration. We performed photon scattering experiments on the odd A neighboring nucleus 141 Pr and found first evidence for the existence of 3 - times 2+circle-times particle-states

  2. Neutron roton pairing effect on some even ven rare-earth proton-rich nuclei

    International Nuclear Information System (INIS)

    Mokhtari, D.

    2004-01-01

    The neutron roton pairing effect on some even ven rare-earth proton-rich nuclei is studied. It is taken into account, in the isovector case, within the framework of the generalized Bogoliubov-Valatin transformation, using Woods-Saxon single-particle energies. (author)

  3. The operator technique in the theory of the rare earth ion interaction with ligand nuclei

    International Nuclear Information System (INIS)

    Anikeenok, O.A.; Eremin, M.V.; Khutsishvili, O.G.

    1986-01-01

    The tensor structure of the operator of rare earth ion interaction with nuclei of close ligands conditioned by virtual processes of charge transport is established. It is taken into account that virtual processes of electron transport from the ligand can take place to the non-filled 4f-, void 5d- and 6s- and preliminarily excited 5p-shells of the rare earth ion. Effects of 4f- and 5d-state mixing by the odd crystal field are considered for the first time. In contrast to the usual multipole-dipole interaction the given one is characterized by anomalously greater significance of highest multipole momenta of the rare earth ion and in the common case it does not have axial symmetry. The theory is compared with data on double electron-nuclear resonance and radiofrequency discrete saturation, taking CaF 2 :Ce 3+ impurity centers as an example

  4. Simulation of statistical γ-spectra of highly excited rare earth nuclei

    International Nuclear Information System (INIS)

    Schiller, A.; Munos, G.; Guttormsen, M.; Bergholt, L.; Melby, E.; Rekstad, J.; Siem, S.; Tveter, T.S.

    1997-05-01

    The statistical γ-spectra of highly excited even-even rare earth nuclei are simulated applying appropriate level density and strength function to a given nucleus. Hindrance effects due to K-conservation are taken into account. Simulations are compared to experimental data from the 163 Dy( 3 He,α) 162 Dy and 173 Yb( 3 He,α) 172 Yb reactions. The influence of the K quantum number at higher energies is discussed. 21 refs., 7 figs., 2 tabs

  5. Transferred hyperfine interaction between the rare-earth ions and the fluorine nuclei in rare-earth trifluorides

    DEFF Research Database (Denmark)

    Hansen, P. E.; Nevald, Rolf; Guggenheim, H. G.

    1978-01-01

    The isotropic and anisotropic transferred hyperfine interactions between F ions in the two chemically inequivalent sites and the rare-earth ions (R) have been derived from 19F NMR measurements in the temperature region 100-300 K on single crystals of TbF3 and DyF3. The isotropic interactions are ...... to vary only slightly with temperature. They are further assigned to definite R's in the unit cell, which cannot be done from macroscopic magnetic measurements....

  6. Spectroscopy of proton-rich nuclei in the rare earth region

    International Nuclear Information System (INIS)

    Toth, K.S.; Nitschke, J.M.; Vierinen, K.S.; Wilmarth, P.A.; Firestone, R.B.; Kortelahti, M.O.

    1990-01-01

    The isotope separator facility OASIS, on-line at the Lawrence Berkeley Laboratory SuperHILAC, was used to investigate proton-rich rare earth nuclei. Single-particle states near the 82-neutron shell were delineated, numerous new isotopes, isomers, and β-delayed proton emitters were discovered and the α-decay properties of some nuclides with N > 84 were reexamined. In this contribution the experimental program is summarized briefly, the excitation energies of the s 1/2 and h 11/2 proton states in this mass region are discussed, and results on the β-delayed-proton spectra of 145 Dy and 147 Er are presented. 17 refs., 5 figs

  7. Decay properties of rare earth nuclei at high excitation and low spin

    International Nuclear Information System (INIS)

    Atac, A.

    1989-01-01

    The purpose of this study was to examine the decay pattern of highly excited rare earth nuclei for which the decay process is expected to be governed by statistical laws. The aim was to investigate how good the statistical model describes the nuclear system and to search for possible deviation from it. It is shown that the gamma decay spectra following both the ( 3 He,α) pick-up reactions and the inelastic ( 3 He, 3 He') reactions reveal similar type of bumps. This leads to the conclusion that the bump structures are not a result of a particular reaction mechanism, but that they have a more general origin. The study is mainly devoted to an examination of the nature of the bumps. 22 refs

  8. Simultaneous projection of particle-number and angular momentum BCS wave-functions in the rare-earth nuclei

    International Nuclear Information System (INIS)

    Oudih, M.R.; Fellah, M.; Allal, N.H.; Benhamouda, N.

    1999-01-01

    It is well established that the BCS wave-functions are neither eigen-functions of the particle-number operator nor of the angular momentum operator. In a previous paper, we have developed a particle-number projection before variation method (of FBCS type). This discrete projection method is based on the SBCS wave-function. The aim of the present contribution is to perform a subsequent angular momentum projection by means of the Peierls-Yoccoz method. The general expression of the system energy, after the double projection, is established in the case of axial symmetry. For practical calculations, an approximation method is introduced. It leads to a semi-classical form of the rotational energy. The rotational spectra have been evaluated numerically for some even-even rare-earth nuclei. The single-particle energies and eigen-states are those of a deformed Woods-Saxon mean field. The obtained results are compared on one hand, to the experimental data, and on the other hand, to the theoretical spectra evaluated by a particle-number projection after variation method (of PBCS type). For all studied nuclei, the spectra determined by the FBCS method reproduce the experimental data better than those of the PBCS method. However, even if the present method is satisfying for low angular momenta, the agreement with the experimental data is lesser for I ≥ 8, particularly for the lighter studied nuclei. (authors)

  9. F-spin study of rare-earth nuclei using F-spin multiplets and angular momentum projected intrinsic states

    International Nuclear Information System (INIS)

    Diallo, A.F.

    1993-01-01

    The proton-neutron Interacting-Boson Model contains both symmetric and mixed-symmetry proton-neutron boson configurations. These states of different proton-neutron symmetry can be classified in terms of an SU(2) symmetry, called F-spin. This dissertation deals with some new applications of F-spin. Even-even nuclei drawn from the proton and neutron shells 50 + scissor mode, and the gyromagnetic ratios of the ground-band members, for which formulas are derived. A no-free-parameter calculation is performed for the summed M1 strength and the centroid energy of ( 146-158 )Sm isotopes. The g factors of deformed and transitional nuclei in the rare-earth mass region are also computed. The data in all cases are found to be well reproduced, in general. A weak L dependence is predicted for the g factors, and there appears to be no need to include two-body terms in the T(M1) operator for determining the M1 strength

  10. Simultaneous projection of particle-number and angular momentum BCS wave-functions in the rare-earth nuclei

    International Nuclear Information System (INIS)

    Oudih, M.R.; Benhamouda, N.; Fellah, M.; Allal, N.H.

    2000-01-01

    A method of simultaneous particle-number and angular-momentum projection of the BCS wave-function is presented. The particle number projection method is of FBCS type. In the frame work of the adiabatic approximation, the rotational energies of the axially symmetric even-even nuclei are established and numerically calculated for the rare-earth region. (author)

  11. Identification of new neutron-rich rare-earth nuclei produced in /sup 252/Cf spontaneous fission

    CERN Document Server

    Greenwood, R C; Gehrke, R J; Meikrantz, D H

    1981-01-01

    A program of systematic study of the decay properties of neutron-rich rare-earth nuclei with 30 srare-earth elemental separations consists of two high-performance chromatography columns connected in series and coupled to the /sup 252 /Cf fission source via a helium gas-jet transport arrangement. The time delay for separation and initiation of gamma -ray counting with results which have been obtained to date with this system include the identification of a number of new neutron-rich rare-earth isotopes including /sup 155/Pm (t/sub 1/2/=48+or-4 s) and /sup 163/Gd (t/sub 1 /2/=68+or-3 s), in addition to 5.51 min /sup 158/Sm which was identified in an earlier series of experiments. (11 refs).

  12. Rare earths

    Energy Technology Data Exchange (ETDEWEB)

    Cranstone, D A

    1979-01-01

    Rare earth elements are commonly extracted from the minerals monazite, bastnaesite, and xenotine. New uses for these elements are constantly developing; they have found applications in glass polishing, television tube phosphors, high-strength low-alloy steels, magnets, catalysts, refractory ceramics, and hydrogen sponge alloys. In Canada, rare earths have been produced as byproducts of the uranium mining industry, but there was no production of rare earths in 1978 or 1979. The world sources of and markets for the rare earth elements are discussed.

  13. The reduced transition probabilities for excited states of rare-earths and actinide even-even nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ghumman, S. S. [Department of Physics, Sant Longowal Institute of Engineering and Technology (Deemed University), Longowal, Sangrur-148106, Punjab, India s-ghumman@yahoo.com (India)

    2015-08-28

    The theoretical B(E2) ratios have been calculated on DF, DR and Krutov models. A simple method based on the work of Arima and Iachello is used to calculate the reduced transition probabilities within SU(3) limit of IBA-I framework. The reduced E2 transition probabilities from second excited states of rare-earths and actinide even–even nuclei calculated from experimental energies and intensities from recent data, have been found to compare better with those calculated on the Krutov model and the SU(3) limit of IBA than the DR and DF models.

  14. An Overlook to Low-Lying 2+ States of Rare Earth Region Nuclei With QRPA Approach

    International Nuclear Information System (INIS)

    Ganioglu, E.

    2008-01-01

    As much as known about the nuclear wave function, as much as known about the nuclear structure. Beyond the mean field to get a better wave function it is a way to introduce correlations on top of the mean field solution by means of random phase approximation. Since QRPA is a useful tool for the collective excitations in this study we studied the first 2 + states by means of QRPA and we examine the limits of QRPA description of nuclear excitation in the rare earth region

  15. Octupole correlations in positive-parity states of rare-earth and actinide nuclei

    Directory of Open Access Journals (Sweden)

    Spieker M.

    2015-01-01

    Full Text Available In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite Jπ = 0+ states in 240Pu. spdf interacting boson model (IBM calculations suggest that the previously proposed double-octupole phonon nature of the Jπ = 0+2 state is not in conflict with its strong (p, t population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positiveand negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (Jπ = 10+ leading to the change in yrast structure observed in 146Nd.

  16. Characteristic 7- and 5- states observed in the (p,t) reactions on even-even rare earth nuclei

    International Nuclear Information System (INIS)

    Ishizaki, Y.; Kubono, S.; Iwasaki, Y.

    1984-01-01

    The (p,t) reactions have been studied for the even-even rare earth nuclei with 40 MeV proton beam from the INS SF cyclotron. A pair of 7 - and 5 - states was observed with large cross sections in each of the nuclei with the neutron number (N) ranging from 86 to 100. For sup(140,142)Nd of N = 80 and 82 the data were obtained at KVI in Groningen, and the data for 152 Sm of N = 90 at MSU. Q value systematics of (p,t) reactions to these states seem to suggest that these are excited by the two neutron pick-up from the neutron core of N = 82. The (p,t) cross sections leading to these states of N from 82 to 96 are nearly constant. (author)

  17. Rare earths

    International Nuclear Information System (INIS)

    1984-01-01

    The conference was held from September 12 to 13, 1984 in Jetrichovice, Czechoslovakia. The participants heard 16 papers of which 4 were inputted in INIS. These papers dealt with industrial separation processes of rare earths, the use of chemical methods of separation from the concentrate of apatite and bastnesite, the effect of the relative permittivity of solvents in the elution of rare earth elements from a cation exchanger, and the determination of the content of different rare earth elements using X-ray fluorescence analysis and atomic absorption spectroscopy. (E.S.)

  18. Description of deformed nuclei in the sdg boson model

    International Nuclear Information System (INIS)

    Li, S.C.; Kuyucak, S.

    1996-01-01

    We present a study of deformed nuclei in the framework of the sdg interacting boson model utilizing both numerical diagonalization and analytical 1/N expansion techniques. The focus is on the description of high-spin states which have recently become computationally accessible through the use of computer algebra in the 1/N expansion formalism. A systematic study is made of high-spin states in rare-earth and actinide nuclei. (orig.)

  19. Description of deformed nuclei in the sdg boson model

    Energy Technology Data Exchange (ETDEWEB)

    Li, S.C. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences; Kuyucak, S. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1996-07-15

    We present a study of deformed nuclei in the framework of the sdg interacting boson model utilizing both numerical diagonalization and analytical 1/N expansion techniques. The focus is on the description of high-spin states which have recently become computationally accessible through the use of computer algebra in the 1/N expansion formalism. A systematic study is made of high-spin states in rare-earth and actinide nuclei. (orig.).

  20. Description of deformed nuclei in the sdg boson model

    Science.gov (United States)

    Li, S. C.; Kuyucak, S.

    1996-02-01

    We present a study of deformed nuclei in the framework of the sdg interacting boson model utilizing both numerical diagonalization and analytical {1}/{N} expansion techniques. The focus is on the description of high-spin states which have recently become computationally accessible through the use of computer algebra in the {1}/{N} expansion formalism. A systematic study is made of high-spin states in rare-earth and actinide nuclei.

  1. Transfer involving deformed nuclei

    International Nuclear Information System (INIS)

    Rasmussen, J.O.; Guidry, M.W.; Canto, L.F.

    1985-03-01

    Results are reviewed of 1- and 2-neutron transfer reactions at near-barrier energies for deformed nuclei. Rotational angular momentum and excitation patterns are examined. A strong tendency to populating high spin states within a few MeV of the yrast line is noted, and it is interpreted as preferential transfer to rotation-aligned states. 16 refs., 12 figs

  2. An Expectation of a backbending for N> 98 of a rare earth nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Salah, M M [Physics Dept., Faculty of Science, Minia University, (Egypt); El-Elgebaly, H [Physics Dept., Faculty of Science, Cairo University, Cairo (Egypt)

    1997-12-31

    The backbending of three neighboring earth nuclei [Er-Yb-Hf] with their isotopes has been studied through the cubic polynomial (CP) theoretical model in addition to [Ex vs. I (I+I)] and [0 vs.{sub 2}] plots, at high energy angular momentum in nuclear rotational bands according to the values of R 4. Also the rotational nuclei are divided into soft and hard rotors by studying the softness S. We expected that there may be a backbending for nuclei of N> 98, but with a High angular momentum, which were not expected before by studying the effect of (I+I) at the critical spin of a backbending. The work includes study of the effective moment of inertia 0eff for these nuclei, and the theoretical treatment to reduce the error in energy calculation of (CP) model. 5 figs., 1 tab.

  3. Modeling level structures of odd-odd deformed nuclei

    International Nuclear Information System (INIS)

    Hoff, R.W.; Kern, J.; Piepenbring, R.; Boisson, J.P.

    1984-01-01

    A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been applied to actinide species where new experimental data have been obtained by use of neutron-capture gamma-ray spectroscopy. The input parameters required for the calculation were derived from empirical data on single-particle excitations in neighboring odd-mass nuclei. Calculated configuration-specific values for the Gallagher-Moszkowski splittings were used. Calculated and experimental level structures for 238 Np, 244 Am, and 250 Bk are compared, as well as those for several nuclei in the rare-earth region. The agreement for the actinide species is excellent, with bandhead energies deviating 22 keV and rotational parameters 5%, on the average. Corresponding average deviations for five rare-earth nuclei are 47 keV and 7%. Several applications of this modeling technique are discussed. 18 refs., 5 figs., 4 tabs

  4. A rare-earth-magnet ion trap for confining low-Z, bare nuclei

    Science.gov (United States)

    Brewer, Samuel M.; Tan, Joseph N.

    2009-05-01

    Simplifications in the theory for Rydberg states of hydrogenlike ions allow a substantial improvement in the accuracy of predicted levels, which can yield information on the values of fundamental constants and test theory if they can be compared with precision frequency measurements.[1] We consider the trapping of bare nuclei (fully-stripped) to be used in making Rydberg states of one-electron ions with atomic number 1Wundt, ``Fundamental constants and tests of theory in Rydberg states of hydrogenlike ions,'' Phys. Rev. Lett. 100, 160404 (2008).

  5. Skyrme RPA description of γ-vibrational states in rare-earth nuclei

    Directory of Open Access Journals (Sweden)

    Nesterenko V.O.

    2016-01-01

    Full Text Available The lowest γ-vibrational states with Kπ = 2+γ in well-deformed Dy, Er and Yb isotopes are investigated within the self-consistent separable quasiparticle random-phase-approximation (QRPA approach based on the Skyrme functional. The energies Eγ and reduced transition probabilities B(E2γ of the states are calculated with the Skyrme force SV-mas10. We demonstrate the strong effect of the pairing blocking on the energies of γ-vibrational states. It is also shown that collectivity of γ-vibrational states is strictly determined by keeping the Nilsson selection rules in the corresponding lowest 2qp configurations.

  6. Transferred hyperfine interaction at 295 K between the rare-earth ions and the fluorine and lithium nuclei in lithium rare-earth fluorides

    DEFF Research Database (Denmark)

    Hansen, P. E.; Nevald, Rolf

    1977-01-01

    The nuclear-magnetic-resonance rotation spectra for the fluorine and lithium nuclei in LiTbF4, LiDyF4, LiHoF4, and LiErF4 have been obtained at 295 K. They are separated in contributions from the dipole and the transferred hyperfine interactions. In general, the latter consists of an isotropic part...

  7. Investigation of neutron-rich rare-earth nuclei including the new isotopes 177Tm and 184Lu

    International Nuclear Information System (INIS)

    Rykaczewski, K.; Gippert, K.L.; Runte, E.; Schmidt-Ott, W.D.; Tidemand-Petersson, P.; Kurcewicz, W.; Nazarewicz, W.

    1989-01-01

    Decays of neutron-rich isotopes in the rare-earth region were studied by means of on-line mass separation and β-γ spectroscopy using multinucleon-transfer reactions between beams of 136 Xe (9 and 11.7 MeV/u), 186 W (11.7 and 15 MeV/u) and 238 U (11.4 MeV/u) and targets of nat W and Ta. The higher beam energies appear to be advantageous for the production of such isotopes. Two new isotopes were identified: 177 Tm with a half-life T 1/2 = 85±10/15 s, and 184 Lu with T 1/2 ≅ 18 s. A new 47 s-activity found at A = 171 is tentatively assigned to the decay of the new isotope 171 Ho. The properties of the ground and excited states of neutron-rich lanthanide isotopes are interpreted within the shell model using the deformed Woods-Saxon potential. A change of the ground-state configuration for odd-mass neutron-rich lutetium isotopes from π 7/2 + [404] to π 9/2 - [514] is suggested, this change being due to the influence of a large hexadecapole deformation. The role of a possible isometric state in 180 Lu for the nucleosynthesis of 180m Ta is discussed. (orig.)

  8. IBA in deformed nuclei

    International Nuclear Information System (INIS)

    Casten, R.F.; Warner, D.D.

    1982-01-01

    The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for 168 Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong β → γ transitions, a feature characteristically absent in the geometrical model, but manifest empirically. Some discrepancies were also noted, principally for the K=4 excitation, and the detailed magnitudes of some specific B(E2) values. Considerable attention is paid to analyzing the structure of the IBA states and their relation to geometric models. The bandmixing formalism was studied to interpret both the aforementioned discrepancies and the origin of the β → γ transitions. The IBA states, extremely complex in the usual SU(5) basis, are transformed to the SU(3) basis, as is the interaction Hamiltonian. The IBA wave functions appear with much simplified structure in this way as does the structure of the associated B(E2) values. The nature of the symmetry breaking of SU(3) for actual deformed nuclei is seen to be predominantly ΔK=0 mixing. A modified, and more consistent, formalism for the IBA-1 is introduced which is simpler, has fewer free parameters (in effect, one, neglecting scale factors on energy differences), is in at least as good agreement with experiment as the earlier formalism, contains a special case of the 0(6) limit which corresponds to that known empirically, and appears to have a close relationship to the IBA-2. The new formalism facilitates the construction of contour plots of various observables (e.g., energy or B(E2) ratios) as functions of N and chi/sub Q/ which allow the parameter-free discussion of qualitative trajectories or systematics

  9. Stretched alignment due to pairing correlation between the normal and abnormal parity orbits for the γ-soft nuclei in the light rare-earth region

    International Nuclear Information System (INIS)

    Ding, H.; Wu, L.

    1996-01-01

    For the γ-soft rotational motion, a two-parameter model is constructed considering the pair correlation between the normal and abnormal parity states based on the fermion dynamical symmetry model. The numerical calculation of this model shows that the data of ground bands of ten typical γ-soft rotational nuclei in the light rare-earth region are fitted in a very high quality. copyright 1996 The American Physical Society

  10. B(IS4;0GS+→4γ+) systematics in rare-earth nuclei: SU sdg (3) description

    International Nuclear Information System (INIS)

    Devi, Y.D.; Kota, V.K.B.

    1993-01-01

    The observed variation of B(IS4; 0 GS + →4 γ + ) with mass number A, that gives information about hexadecupole component in γ-vibration, in rare-earth nuclei is studied in the SU sdg (3) limit of sdg interacting boson model empoloying IBM-2 to IBM-1 projected hexadecupole transition operator with effective charges determined using a multi-j shell mapping procedure. The SU sdg (3) limit provides a reasonably good description of the data. (orig.)

  11. Problem of ''deformed'' superheavy nuclei

    International Nuclear Information System (INIS)

    Sobiczewski, A.; Patyk, Z.; Muntian, I.

    2000-08-01

    Problem of experimental confirmation of deformed shapes of superheavy nuclei situated in the neighbourhood of 270 Hs is discussed. Measurement of the energy E 2+ of the lowest 2+ state in even-even species of these nuclei is considered as a method for this confirmation. The energy is calculated in the cranking approximation for heavy and superheavy nuclei. The branching ratio p 2+ /p 0+ between α decay of a nucleus to this lowest 2+ state and to the ground state 0+ of its daughter is also calculated for these nuclei. The results indicate that a measurement of the energy E 2+ for some superheavy nuclei by electron or α spectroscopy is a promising method for the confirmation of their deformed shapes. (orig.)

  12. Neutron scattering on deformed nuclei

    International Nuclear Information System (INIS)

    Hansen, L.F.; Haight, R.C.; Pohl, B.A.; Wong, C.; Lagrange, C.

    1984-09-01

    Measurements of neutron elastic and inelastic differential cross sections around 14 MeV for 9 Be, C, 181 Ta, 232 Th, 238 U and 239 Pu have been analyzed using a coupled channel (CC) formalism for deformed nuclei and phenomenological global optical model potentials (OMP). For the actinide targets these results are compared with the predictions of a semi-microscopic calculation using Jeukenne, Lejeune and Mahaux (JLM) microscopic OMP and a deformed ground state nuclear density. The overall agreement between calculations and the measurements is reasonable good even for the very light nuclei, where the quality of the fits is better than those obtained with spherical OMP

  13. Neutron halo in deformed nuclei

    International Nuclear Information System (INIS)

    Zhou Shangui; Meng Jie; Ring, P.; Zhao Enguang

    2010-01-01

    Halo phenomena in deformed nuclei are investigated within a deformed relativistic Hartree Bogoliubov (DRHB) theory. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Contributions of the halo, deformation effects, and large spatial extensions of these systems are described in a fully self-consistent way by the DRHB equations in a spherical Woods-Saxon basis with the proper asymptotic behavior at a large distance from the nuclear center. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nucleus 44 Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the occurrence of this decoupling effects are discussed.

  14. Phonon operators in deformed nuclei

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1981-01-01

    For the description of the excited states in deformed nuclei new phonon operators are introduced, which depend on the sign of the angular momentum projection onto the symmetry axis of a deformed nucleus. In the calculations with new phonons the Pauli principle is correctly taken into account in the two-phonon components of the wave functions. There is a difference in comparison with the calculation with phonons independent of the sign of the angular momentum projection. The new phonons should be used in deformed nuclei if the Pauli principle is consistently taken into account and in the calculations with the excited state wave functions having the components with more than one phonon operator [ru

  15. Phonon operators for deformed nuclei

    International Nuclear Information System (INIS)

    Solov'ev, V.G.

    1982-01-01

    The mathematical formalism with the phonon operators independent of the signature of the angular momentum projection turns out to be inadequate for describing excited states of deformed nuclei. New phonon operators are introduced which depend on the signature of the angular momentum projection on the symmetry axis of a deformed nucleus. It is shown that the calculations with the new phonons take correctly into account the Pauli principle in two-phonon components of wave functions. The results obtained differ from those given by the phonons independent of the signature of the angular momentum projection. The new phonons must be used in deformed nuclei at taking systematically the Pauli principle into account and in calculations involving wave functions of excited states having components with more than one-phonon operator

  16. Rare earth germanates

    International Nuclear Information System (INIS)

    Bondar', I.A.; Vinogradova, N.V.; Dem'yanets, L.N.

    1983-01-01

    Rare earth germanates attract close attention both as an independent class of compounds and analogues of a widely spread class of natural and synthetic minerals. The methods of rare earth germanate synthesis (solid-phase, hydrothermal) are considered. Systems on the basis of germanium and rare earth oxides, phase diagrams, phase transformations are studied. Using different chemical analysese the processes of rare earth germanate formation are investigated. IR spectra of alkali and rare earth metal germanates are presented, their comparative analysis being carried out. Crystal structures of the compounds, lattice parameters are studied. Fields of possible application of rare earth germanates are shown

  17. Identification of new proton-rich rare earth nuclei by means of the coupled system helium jet-isotope separator of SARA

    International Nuclear Information System (INIS)

    Ollivier, T.

    1986-01-01

    In order to study new exotic nuclei far from stability we built a fast separation system by coupling a helium jet with the medium-current source of the mass separator. First the tests were made in Lyon and then the system used on line with the heavy ion accelerator SARA, in Grenoble. We obtained efficiency greater than 1% for each element and a better chemical independence. This allowed us to perform experiments on rare-earth region near N=82, with fusion-evaporation reactions after an investigation of various ranges of beam energies. The first results allow to identify two new isotopes, 143 Tb (12s) and 138 Eu (12s). The decay schemes obtained are analysed in the frame of existing models [fr

  18. Rare earth sulfates

    International Nuclear Information System (INIS)

    Komissarova, L.N.; Shatskij, V.M.; Pokrovskij, A.N.; Chizhov, S.M.; Bal'kina, T.I.; Suponitskij, Yu.L.

    1986-01-01

    Results of experimental works on the study of synthesis conditions, structure and physico-chemical properties of rare earth, scandium and yttrium sulfates, have been generalized. Phase diagrams of solubility and fusibility, thermodynamic and crystallochemical characteristics, thermal stability of hydrates and anhydrous sulfates of rare earths, including normal, double (with cations of alkali and alkaline-earth metals), ternary and anion-mixed sulfates of rare earths, as well as their adducts, are considered. The state of ions of rare earths, scandium and yttrium in aqueous sulfuric acid solutions is discussed. Data on the use of rare earth sulfates are given

  19. Self-consistent field description of high spin states in rare earth nuclei. [Hartree-Fock-Bogolyubov Theory

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, A L [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)

    1976-07-12

    The Hartree-Fock-Bogolyubov cranking equations are solved for /sup 168/ /sup 170/Yb and /sup 174/Hf. Deformation and pairing properties are both obtained with a G-matrix derived from the Reid soft-core potential. The high spin anomalies are attributed to the disappearance of the neutron pair gap in /sup 168/Yb, the realignment of an isub(13/2) neutron pair in /sup 170/Yb, and a combination of these two mechanisms in /sup 174/Hf. Two bands intersecting at high spin are found for /sup 174/Hf.

  20. Rare earth octacyanomolybdates(4)

    International Nuclear Information System (INIS)

    Zubritskaya, D.I.; Sergeeva, A.N.; Pisak, Yu.V.

    1980-01-01

    Optimal conditions for synthesis of rare-earth octacyanomolybdates(4) of the Ln 4 [Mo(CN) 8 ] 3 xnH 2 O composition (where Ln is a rare-earth element, other than Pr, Pm, Lu, Tb) have been worked out. The synthesis has been accomplished by neutralization with octacianomolybdic acid with rare-earth carbonates. The composition and structure of the compounds synthesized have been studied by infrared-spectroscopy. It has been established that rare-earth octacyanomolybdates(4) form three isostructural groups

  1. Systematics of Absolute Gamma Ray Transition Probabilities in Deformed Odd-A Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Malmskog, S G

    1965-11-15

    All known experimentally determined absolute gamma ray transition probabilities between different intrinsic states of deformed odd-A nuclei in the rare earth, region (153 < A < 181) and in the actinide region (A {>=} 227) are compared with transition probabilities (Weisskopf and Nilsson estimate). Systematic deviations from the theoretical values are found. Possible explanations for these deviations are given. This discussion includes Coriolis coupling, {delta}K ={+-}2 band-mixing effects and pairing interaction.

  2. Barriers in the energy of deformed nuclei

    Directory of Open Access Journals (Sweden)

    V. Yu. Denisov

    2014-06-01

    Full Text Available Interaction energy between two nuclei considering to their deformations is studied. Coulomb and nuclear in-teraction energies, as well as the deformation energies of both nuclei, are taken into account at evaluation of the interaction energy. It is shown that the barrier related to the interaction energy of two nuclei depends on the de-formations and the height of the minimal barrier is evaluated. It is obtained that the heavier nucleus-nucleus sys-tems have large deformation values at the lowest barrier. The difference between the barrier between spherical nuclei and the lowest barrier between deformed nuclei increases with the mass and the charge of the interacting nuclei.

  3. Rare earth germanates

    International Nuclear Information System (INIS)

    Bondar', I.A.; Vinogradova, N.V.; Dem'yanets, L.N.

    1983-01-01

    From the viewpoint of structural chemistry and general regularities controlling formation reactions of compounds and phases in melts, solid and gaseous states, recent achievements in the chemistry of rare earth germanates are generalized. Methods of synthesizing germanates, systems on the base of germanium oxides and rare earths are considered. The data on crystallochemical characteristics are tabulated. Individual compounds of scandium germanate are also characterized. Processes of germanate formation using the data of IR-spectroscopy, X-ray phase analysis are studied. The structure and morphotropic series of rare earth germanates and silicates are determined. Fields of their present and possible future application are considered

  4. Effect of rare earth elements on deformation behavior of an extruded Mg–10Gd–3Y–0.5Zr alloy during compression

    International Nuclear Information System (INIS)

    Mirza, F.A.; Chen, D.L.; Li, D.J.; Zeng, X.Q.

    2013-01-01

    Highlights: ► The alloy studied has threefold higher compressive yield strength than AM30 alloy. ► Formation of twins is less extensive than that in the RE-free extruded Mg alloys. ► Deformation of the RE-containing Mg alloy is characterized by three distinct stages. ► Rare earth elements effectively increase the strain hardening rate in stage A. ► Fairly flat and linear strain hardening occurs in stage B over an extended range. - Abstract: The aim of this study was to identify the influence of rare-earth (RE) elements on the strain hardening behavior in an extruded Mg–10Gd–3Y–0.5Zr magnesium alloy via compression in the extrusion direction at room temperature. The plastic deformation behavior of this RE-containing alloy was characterized by a rapidly decreasing strain hardening rate up to a strain level of about 4% (stage A), followed by a fairly flat linear strain hardening rate over an extended strain range from ∼4% to ∼18% (stage B). Stage C was represented by a decreasing strain hardening rate just before failure. The extent of twinning in this alloy was observed to be considerably less extensive than that in the RE-free extruded Mg alloys. The weaker crystallographic texture, refined grain size, and second-phase particles arising from the addition of RE elements were responsible for the much higher strain hardening rate in stage A due to the increased difficulty on the formation of twins and the slip of dislocations at lower strains, and for the occurrence of quite flat linear strain hardening in stage B at higher strains which was likely related to the dislocation debris and twin debris (or residual twins) stemming from dislocation–twin interactions as well as the interactions between dislocations/twins and second-phase particles and grain boundaries

  5. Rare earths and actinides

    International Nuclear Information System (INIS)

    Coqblin, B.

    1982-01-01

    This paper reviews the different properties of rare-earths and actinides, either as pure metals or as in alloys or compounds. Three different cases are considered: (i) First, in the case of 'normal' rare-earths which are characterized by a valence of 3, we discuss essentially the magnetic ordering, the coexistence between superconductivity and magnetism and the properties of amorphous rare-earth systems. (ii) Second, in the case of 'anomalous' rare-earths, we distinguish between either 'intermediate-valence' systems or 'Kondo' systems. Special emphasis is given to the problems of the 'Kondo lattice' (for compounds such as CeAl 2 ,CeAl 3 or CeB 6 ) or the 'Anderson lattice' (for compounds such as TmSe). The problem of neutron diffraction in these systems is also discussed. (iii) Third, in the case of actinides, we can separate between the d-f hybridized and almost magnetic metals at the beginning of the series and the rare-earth like the metals after americium. (orig.)

  6. Rare (Earth Elements [score

    Directory of Open Access Journals (Sweden)

    Camilo Méndez

    2014-12-01

    Full Text Available Rare (Earth Elements is a cycle of works for solo piano. The cycle was inspired by James Dillon’s Book of Elements (Vol. I-V. The complete cycle will consist of 14 pieces; one for each selected rare (earth element. The chosen elements are Neodymium, Erbium, Tellurium, Hafnium, Tantalum, Technetium, Indium, Dysprosium, Lanthanium, Cerium, Europium, Terbium, Yttrium and Darmstadtium. These elements were selected due to their special atomic properties that in many cases make them extremely valuable for the development of new technologies, and also because of their scarcity. To date, only 4 works have been completed Yttrium, Technetium, Indium and Tellurium.

  7. Electron form factors of deformable nuclei

    International Nuclear Information System (INIS)

    Tartakovskii, V.K.; Isupov, V.Yu.

    1988-01-01

    Using the smallness of the deformation parameter of the nucleus, we obtain simple explicit expressions for the form factors of electroexcitation of the low-lying rotation-vibration states of light, deformable, even-even nuclei. The expressions satisfactorily describe the experimental data on the excitation of collective nuclear states by the inelastic scattering of fast electrons

  8. Magnetic rare earth superlattices

    DEFF Research Database (Denmark)

    Majkrzak, C.F.; Kwo, J.; Hong, M.

    1991-01-01

    Advances in molecular beam epitaxy deposition techniques have recently made it possible to grow, an atomic plane at a time, single crystalline superlattices composed of alternating layers of a magnetic rare earth, such as Gd, Dy, Ho, or Er, and metallic Y, which has an identical chemical structure...

  9. Afganistan and rare earths

    Directory of Open Access Journals (Sweden)

    Emilian M. Dobrescu

    2013-05-01

    Full Text Available On our planet, over a quarter of new technologies for the economic production of industrial goods, are using rare earths, which are also called critical minerals and industries that rely on these precious items being worth of an estimated nearly five trillion dollars, or 5 percent of world gross domestic product. In the near future, competition will increase for the control of rare earth minerals embedded in high-tech products. Rare minerals are in the twenty-first century what oil accounted for in the twentieth century and coal in the nineteenth century: the engine of a new industrial revolution. Future energy will be produced increasingly by more sophisticated technological equipment based not just on steel and concrete, but incorporating significant quantities of metals and rare earths. Widespread application of these technologies will result in an exponential increase in demand for such minerals, and what is worrying is that minerals of this type are almost nowhere to be found in Europe and in other industrialized countries in the world, such as U.S. and Japan, but only in some Asian countries, like China and Afghanistan.

  10. Low-energy E1 transitions and octupole softness in odd-A deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hagemann, G B [Niels Bohr Inst., Copenhagen (Denmark); Hamamoto, I [Lund Univ. (Sweden). Dept. of Mathematical Physics; Kownacki, J; Satula, W [Warsaw Univ. (Poland)

    1992-08-01

    It is found that B(E1) values for yrast spectroscopy of deformed odd-A rare-earth nuclei calculated by using a model in which one quasiparticle is coupled to a rotor are more than an order of magnitude too small. Therefore, measured B(E1) values for {sup 169}Lu were analyzed by introducing parameters which effectively took octupole softness into account. Some preliminary results of the theoretical analysis which are presented in this paper still give do not agree completely with experiment. 4 refs., 1 tab., 5 figs.

  11. ''Identical'' bands in normally-deformed nuclei

    International Nuclear Information System (INIS)

    Garrett, J.D.; Baktash, C.; Yu, C.H.

    1990-01-01

    Gamma-ray transitions energies in neighboring odd- and even-mass nuclei for normally-deformed nuclear configurations are analyzed in a manner similar to recent analyses for superdeformed states. The moment of inertia is shown to depend on pair correlations and the aligned angular momentum of the odd nucleon. The implications of this analysis for ''identical'' super-deformed bands are discussed. 26 refs., 9 figs

  12. The superdeformed isotope chains in the rare-earth region

    International Nuclear Information System (INIS)

    Dong Baoguo; Chen Yongshou; Jin Xingnan

    1990-01-01

    Self-consistent calculations with respect to ε 2 and γ based on the cranked Nilsson model were done systematically for the superdeformed rotational states of nuclei in the rare-earth region. The results indicate that there exist a number of super-deformed isotope chains with neutron number N = 80-86 and quadrupole deformation ε 2 0.5-0.6. The calculated minimum angular momentum at which the superdeformed state becomes yrast has an average value of 60 ℎ and increases as the number of neutron increases within the chain. The calculation of shell correction energy surface indicates that the contribution of the neutron system is mostly responsible for the super-deformation

  13. Rare Earth Polyoxometalates.

    Science.gov (United States)

    Boskovic, Colette

    2017-09-19

    Longstanding and important applications make use of the chemical and physical properties of both rare earth metals and polyoxometalates of early transition metals. The catalytic, optical, and magnetic features of rare earth metal ions are well-known, as are the reversible multielectron redox and photoredox capabilities of polyoxomolybdates and polyoxotungstates. The combination of rare earth ions and polyoxometalates in discrete molecules and coordination polymers is of interest for the unique combination of chemical and physical properties that can arise. This Account surveys our efforts to synthesize and investigate compounds with rare earth ions and polyoxometalates (RE-POMs), sometimes with carboxylate-based organic coligands. Our general synthetic approach is "bottom-up", which affords well-defined nanoscale molecules, typically in crystalline form and amenable to single-crystal X-ray diffraction for structure determination. Our particular focus is on elucidation of the physical properties conferred by the different structural components with a view to ultimately being able to tune these properties chemically. For this purpose, we employ a variety of spectroscopic, magnetochemical, electrochemical, and scattering techniques in concert with theoretical modeling and computation. Studies of RE-POM single-molecule magnets (SMMs) have utilized magnetic susceptibility, inelastic neutron scattering, and ab initio calculations. These investigations have allowed characterization of the crystal field splitting of the rare earth(III) ions that is responsible for the SMM properties of slow magnetic relaxation and magnetization quantum tunneling. Such SMMs are promising for applications in quantum computing and molecular spintronics. Photophysical measurements of a family of hybrid RE-POMs with organic ligands have afforded insights into sensitization of Tb(III) and Eu(III) emission through both organic and polyoxometalate chromophores in the same molecule. Detailed

  14. Transmission coefficents in strongly deformed nuclei

    International Nuclear Information System (INIS)

    Aleshin, V.P.

    1996-01-01

    By using our semiclassical approach to particle evaporation from deformed nuclei developed earlier, we analyze here the heuristic methods of taking into account the effects of shape deformations on particle emission. These methods are based on the 'local' transmission coefficients in which the effective barrier depends on the angle with respect to the symmetry axis. The calculations revealed that the heuristic models are reasonable for particle energy spectra but fail, at large deformations, to describe the angular distributions. In A∼160 nuclei with axis ratio in the vicinity of 2:1 at temperatures of 2-3 MeV, the W (90 )/W(0 ) anisotropies of α particles with respect to the nuclear spin are 1.5 to 3 times larger than our approach predicts. The influence of spin alignment on particle energy spectra is discussed shortly. (orig.)

  15. Static and dynamic deformations of actinide nuclei

    International Nuclear Information System (INIS)

    Rozmej, P.

    1985-09-01

    The zero-point quadrupole-hexadecapole vibrations have been taken into account to calculate dynamical deformations for even-even actinide nuclei. The collective and intrinsic motions are separated according to the Born-Oppenheimer approximation. The collective Hamiltonian is constructed using the macroscopic-microscopic method in the potential energy part and the cranking model in the kinetic energy part. The BCS theory with a modified oscillator potential is applied to describe the intrinsic motion of nucleons. A new set of Nilsson potential parameters, which produces a much better description of the properties of light actinide nuclei, has also been found. (orig.)

  16. Rare earth superlattices

    International Nuclear Information System (INIS)

    McMorrow, D.F.

    1997-01-01

    A review is given of recent experiments on the magnetism of rare earth superlattices. Early experiments in this field were concerned mainly with systems formed by combining a magnetic and a non-magnetic element in a superlattice structure. From results gathered on a variety of systems it has been established that the propagation of magnetic order through the non-magnetic spacer can be understood mostly on the basis of an RKKY-like model, where the strength and range of the coupling depends on the details of the conduction electron susceptibility of the spacer. Recent experiments on more complex systems indicate that this model does not provide a complete description. Examples include superlattices where the constituents can either be both magnetic, adopt different crystal structures (Fermi surfaces), or where one of the constituents has a non-magnetic singlet ground state. The results from such systems are presented and discussed in the context of the currently accepted model. (au)

  17. Rare earth (3) pivalates

    International Nuclear Information System (INIS)

    Kuz'mina, N.P.; Martynenko, L.I.; Zoan An' Tu; Ch'eu Tkhi Nguet; Troyanov, S.I.; Rykov, A.N.; Korenev, Yu.M.

    1994-01-01

    Depending on synthesis conditions rare earth pivalates can be obtained in the form of either adducts NPiv·HPiv or hydrates MPiv 3 ·mH 2 O. Adducts are the most stable form of pivalates. Heating of adducts result in formation of corresponding MPiv 3 . MPiv 3 ·nHPiv compounds are characterized by IR-spectroscopy and thermal analysis data. Behaviour of MPiv 3 was studied in the regime of vacuum sublemation. Using mass spectroscopy of NdPiv 3 it was shown that gaseous phase above MPiv 3 had complex composition and contained ligomer fragments. X-ray structure analysis of [NdPiv 3 ·3HPiv] was conducted

  18. Nuclear shape transitions and some properties of aligned-particle configurations at very high spin in some rare-earth nuclei

    International Nuclear Information System (INIS)

    Mansour, N.; Bayomy, T.; Awwad, Z.

    1990-01-01

    We will present results on an collective ΔI = 2 ground band level sequence in the spherical six-valence-particle nucleus 152 Dy and the variation of shapes for nuclei in the N = 88 to 92 transitional region. Finally, we will present results for some even-even nuclei without any backbending behaviour, showed a clear backbending in the diagram of 2Φ/(h/2π) 2 versus (hw/2π) 2 . (author)

  19. China's rare-earth industry

    Science.gov (United States)

    Tse, Pui-Kwan

    2011-01-01

    Introduction China's dominant position as the producer of over 95 percent of the world output of rare-earth minerals and rapid increases in the consumption of rare earths owing to the emergence of new clean-energy and defense-related technologies, combined with China's decisions to restrict exports of rare earths, have resulted in heightened concerns about the future availability of rare earths. As a result, industrial countries such as Japan, the United States, and countries of the European Union face tighter supplies and higher prices for rare earths. This paper briefly reviews China's rare-earth production, consumption, and reserves and the important policies and regulations regarding the production and trade of rare earths, including recently announced export quotas. The 15 lanthanide elements-lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium (atomic numbers 57-71)-were originally known as the rare earths from their occurrence in oxides mixtures. Recently, some researchers have included two other elements-scandium and yttrium-in their discussion of rare earths. Yttrium (atomic number 39), which lies above lanthanum in transition group III of the periodic table and has a similar 3+ ion with a noble gas core, has both atomic and ionic radii similar in size to those of terbium and dysprosium and is generally found in nature with lanthanides. Scandium (atomic number 21) has a smaller ionic radius than yttrium and the lanthanides, and its chemical behavior is intermediate between that of aluminum and the lanthanides. It is found in nature with the lanthanides and yttrium. Rare earths are used widely in high-technology and clean-energy products because they impart special properties of magnetism, luminescence, and strength. Rare earths are also used in weapon systems to obtain the same properties.

  20. Rare earths 1998 market update

    International Nuclear Information System (INIS)

    Tourre, J.M.

    1998-01-01

    The rare earth industry has always been a world of rapid change with the emergence of new markets, new ores and new players, as well as the disappearance of old applications. Rare earth based products are used in a great diversity of applications such as hard disk drives, CD drives, batteries, capacitors, pigments, ceramics, polishing powders, fuel cells, flints, catalyst converter, fluid cracking catalysts, etc. South East Asia holds the largest share of the known reserve of rare earth ores and is one of the major markets for rare earth compounds; in the last ten years, China has become the largest producer of rare earth intermediates as well as an important exporter of separated rare earth elements. Today, China has approximately 150 factories producing rare earth compounds, most of which are experiencing financial difficulties due to the lack of knowledge of true market needs, lack of control of their distribution channels and production over-capacity. Recently the Chinese rare earth producers have recognized the situation and efforts are underway to rationalize rare earth production. Japan has dominated many of the major application markets, and is by far the largest market for metal and alloy products. This will remain the case for the next five years; however, new countries are emerging as significant users of rare earth products such as Korea, Taiwan and Malaysia. During the last ten years rare earth producers adjusted to several radical changes that affected the raw materials, the application mix and the price structure. New producers have emerged, especially from China; some have subsequently stopped their activities while others have focused their efforts in a specific market segment

  1. Geometry and dynamics of particle emission from strongly deformed nuclei

    International Nuclear Information System (INIS)

    Aleshin, V.P.

    1995-01-01

    By using our semiclassical approach to particle evaporation from deformed nuclei, we analyze the heuristic models of particle emission from deformed nuclei which are used in the codes GANES, ALICE, and EVAP. The calculations revealed that the heuristic models are reasonable for particle energy spectra but fail, at large deformations, to describe the angular distributions

  2. Rare-earth elements

    Science.gov (United States)

    Van Gosen, Bradley S.; Verplanck, Philip L.; Seal, Robert R.; Long, Keith R.; Gambogi, Joseph; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    The rare-earth elements (REEs) are 15 elements that range in atomic number from 57 (lanthanum) to 71 (lutetium); they are commonly referred to as the “lanthanides.” Yttrium (atomic number 39) is also commonly regarded as an REE because it shares chemical and physical similarities and has affinities with the lanthanides. Although REEs are not rare in terms of average crustal abundance, the concentrated deposits of REEs are limited in number.Because of their unusual physical and chemical properties, the REEs have diverse defense, energy, industrial, and military technology applications. The glass industry is the leading consumer of REE raw materials, which are used for glass polishing and as additives that provide color and special optical properties to the glass. Lanthanum-based catalysts are used in petroleum refining, and cerium-based catalysts are used in automotive catalytic converters. The use of REEs in magnets is a rapidly increasing application. Neodymium-iron-boron magnets, which are the strongest known type of magnets, are used when space and weight are restrictions. Nickel-metal hydride batteries use anodes made of a lanthanum-based alloys.China, which has led the world production of REEs for decades, accounted for more than 90 percent of global production and supply, on average, during the past decade. Citing a need to retain its limited REE resources to meet domestic requirements as well as concerns about the environmental effects of mining, China began placing restrictions on the supply of REEs in 2010 through the imposition of quotas, licenses, and taxes. As a result, the global rare-earth industry has increased its stockpiling of REEs; explored for deposits outside of China; and promoted new efforts to conserve, recycle, and substitute for REEs. New mine production began at Mount Weld in Western Australia, and numerous other exploration and development projects noted in this chapter are ongoing throughout the world.The REE-bearing minerals are

  3. Rare earth metals, rare earth hydrides, and rare earth oxides as thin films

    International Nuclear Information System (INIS)

    Gasgnier, M.

    1980-01-01

    The review deals with pure rare earth materials such as rare earth metals, rare earth hydrides, and rare earth oxides as thin films. Several preparation techniques, control methods, and nature of possible contaminations of thin films are described. These films can now be produced in an extremely well-known state concerning chemical composition, structure and texture. Structural, electric, magnetic, and optical properties of thin films are studied and discussed in comparison with the bulk state. The greatest contamination of metallic rare earth thin films is caused by reaction with hydrogen or with water vapour. The compound with an f.c.c. structure is the dihydride LnH 2 (Ln = lanthanides). The oxygen contamination takes place after annealing at higher temperatures. Then there appears a compound with a b.c.c. structure which is the C-type sesquioxide C-Ln 2 O 3 . At room atmosphere dihydride light rare earth thin films are converted to hydroxide Ln(OH) 3 . For heavy rare earth thin films the oxinitride LnNsub(x)Osub(y) is observed. The LnO-type compound was never seen. The present review tries to set the stage anew for the investigations to be undertaken in the future especially through the new generations of electron microscopes

  4. Rare earth industries: Downstream business

    International Nuclear Information System (INIS)

    2011-01-01

    The value chain of the rare earths business involves mining, extraction, processing, refining and the manufacture of an extensive range of downstream products which find wide applications in such industries including aerospace, consumer electronics, medical, military, automotive, renewable wind and solar energy and telecommunications. In fact the entire gamut of the high-tech industries depends on a sustainable supply of rare earths elements. The explosive demand in mobile phones is an excellent illustration of the massive potential that the rare earths business offers. In a matter of less than 20 years, the number of cell phones worldwide has reached a staggering 5 billion. Soon, going by the report of their growth in sales, the world demand for cell phones may even exceed the global population. Admittedly, the rare earths business does pose certain risks. Top among the risks are the health and safety risks. The mining, extraction and refining of rare earths produce residues and wastes which carry health and safety risks. The residues from the extraction and refining are radioactive, while their effluent waste streams do pose pollution risks to the receiving rivers and waterways. But, as clearly elaborated in a recent report by IAEA experts, there are technologies and systems available to efficiently mitigate such risks. The risks are Rare Earth manageable. However, it is crucial that the risk and waste management procedures are strictly followed and adhered to. This is where effective monitoring and surveillance throughout the life of all such rare earths facilities is crucial. Fortunately, Malaysia's regulatory standards on rare earths follow international standards. In some areas, Malaysia's regulatory regime is even more stringent than the international guidelines. (author)

  5. Rare earth metal alloy magnets

    International Nuclear Information System (INIS)

    Harris, I.R.; Evans, J.M.; Nyholm, P.S.

    1979-01-01

    This invention relates to rare earth metal alloy magnets and to methods for their production. The technique is based on the fact that rare earth metal alloys (for e.g. cerium or yttrium) which have been crumbled to form a powder by hydride formation and decomposition can be used for the fabrication of magnets without the disadvantages inherent in alloy particle size reduction by mechanical milling. (UK)

  6. Safety aspects in rare earths recovery

    International Nuclear Information System (INIS)

    Bhattacharya, R.

    2014-01-01

    Recovery of rare earths involves mining of beach sands, mineral separation to obtain monazite and its chemical processing to obtain rare earth composites. The composites are then subjected to further chemical treatment to obtain individual rare earths. Although the separated out rare earths are not radioactive, the process for recovery of rare earths involve both radiological as well as conventional hazards. This paper highlights the safety aspects in the mining, mineral separation and chemical processing of monazite to obtain rare earths

  7. Effective field theory for triaxially deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Q.B. [Technische Universitaet Muechen, Physik-Department, Garching (Germany); Peking University, State Key Laboratory of Nuclear Physics and Technology, School of Physics, Beijing (China); Kaiser, N. [Technische Universitaet Muechen, Physik-Department, Garching (Germany); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Institute for Advanced Simulation, Institut fuer Kernphysik, Juelich Center for Hadron Physics and JARA-HPC, Forschungszentrum Juelich, Juelich (Germany); Meng, J. [Peking University, State Key Laboratory of Nuclear Physics and Technology, School of Physics, Beijing (China); Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); University of Stellenbosch, Department of Physics, Stellenbosch (South Africa)

    2017-10-15

    Effective field theory is generalized to investigate the rotational motion of triaxially deformed even-even nuclei. The Hamiltonian for the triaxial rotor is obtained up to next-to-leading order within the effective field theory formalism. Its applicability is examined by comparing with a five-dimensional rotor-vibrator Hamiltonian for the description of the energy spectra of the ground state and γ band in Ru isotopes. It is found that by taking into account the next-to-leading order corrections, the ground state band in the whole spin region and the γ band in the low spin region are well described. The deviations for high-spin states in the γ bands point towards the importance of including vibrational degrees of freedom in the effective field theory formulation. (orig.)

  8. Symmetries of the nuclear average field hamiltonian and a search for possible exotic equilibrium deformations in superdeformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Li Xunjun; Dudek, J.; Romain, P. (Centre de Recherches Nucleaires, IN2P3-CNRS, Univ. Louis Pasteur, 67 - Strasbourg (France))

    1991-11-21

    Symmetry properties of the general average-field hamiltonian-matrix resulting from the geometrical symmetries of the hamiltonian itself are derived and discussed. The corresponding numerical algorithms are constructed. Total energy calculations for superdeformed nuclei are then extended to include the usually neglected deformation modes {alpha}{sub {lambda}=3{mu}{ne}0} in the expansion of the nuclear surface expression R({theta}, {phi}; {l brace}{alpha}{r brace})=c({l brace}{alpha}{r brace})R{sub 0}(1+{Sigma}{sub {lambda}} {Sigma}{sub {mu}=-{lambda}}{sup {lambda}} {alpha}{sub {lambda}{mu}}{sup *}{Upsilon}{sub {lambda}{mu}}({theta}, {phi})). The general trends in the shell-energy dependence on {alpha}{sub {lambda}=3{mu}} and the implied instabilities in the superdeformed configurations of the rare earth nuclei are studied using the Strutinsky formula with the macroscopic part taken in the form of the folded-Yukawa plus exponential interaction. A possibility of new (double superdeformed minimum) structures coexisting in some nuclei and resulting from the proton shell effects is predicted and illustrated. No significant neutron effects are found in the rare earth superdeformed nuclei considered. (orig.).

  9. Isobaric analog states in rare-earth nuclei studied with the (3He,t) charge-exchange reaction at thetasub(L)=00

    International Nuclear Information System (INIS)

    Jaenecke, J.

    1983-01-01

    The ( 3 He, t) charge-exchange reaction leading to the ground-state isobaric analog states (IAS) of sup(152, 154, 156, 158, 160)Gd, sup(160, 162)Dy, sup(162, 164, 166, 168, 170)Er, sup(170, 172, 174, 176)Yb and sup(176, 178, 180)Hf has been studied at thetasub(L) = 0 0 and E( 3 He) = 60.5 MeV. The reaction 28 Si( 3 He, t) 28 P was used for energy calibration. The centroid energies of most IAS were determined to +- 6 keV. Coulomb displacement energies have been extracted from the measured Q-values. They display the influence of non-spherical nuclear shapes which increase the rms radii and lower the Coulomb displacement energies. The dependence on both quadrupole and hexadecapole deformations is apparent with deformation parameters in good agreement with results from other measurements. The total widths GAMMA of the IAS are in the range 30 to 110 keV. They increase more strongly with neutron excess than is known for the IAS of the Sn and Te isotopes. The width of the IAS of 176 Yb is anomalously low. The zero-degree ( 3 He, t) cross sections are in the range 5 to 20 μb/sr. They generally increase with neutron excess except for the sequence of Yb isotopes. No systematic dependence on (N - Z) appears to exist. Excitation energies and zero-degree cross sections for the reactions 28 Si( 3 He, t) 28 P, 16 O( 3 He, t) 16 F and 12 C( 3 He,t) 12 N are reported. (orig.)

  10. Sc, Y, La-Lu - Rare Earth Elements

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    At present extensive efforts are being made in completing work on system number Rare Earth Elements. Part A is devoted to the occurrence of these elements on the earth and in the universe. Part B deals with the pure metals; the 7 volumes published cover the description of the separation from the raw materials, the preparation of pure metals,their uses and toxicology, the physical properties of nuclei, atoms, molecules, and isotopes; in addition the behavior of ions in solution and the electrochemical behavior of rare earth elements are described. The compounds are described in Part C. Part D with 6 volumes has been devoted to the description of coordination compounds and is completed. The volume ''Rare Earth Elements C 10'' deals with the rare earth tellurides, oxide tellurides, tellurates, telluride halides, tellurate halides, sulfide tellurides, selenide tellurides, and alkali rare earth tellurates. Another topic of this volume are the compounds of the rare earth elements with polonium. So far as meaningful and in accordance with all earlier volumes of ''Rare Earth Elements'' Series C, comparative data are presented in sections preceding treatment of the individual compounds and systems

  11. Rare earths as a future resource

    International Nuclear Information System (INIS)

    Cornell, D.H.

    1988-01-01

    The fourteen rare earth or lanthanide elements have recently emerged as an important natural resource because of the rapidly growing demand in the electronic, chemical and metallurgical industries. The Symposium on rare earth elements as a future resource presented a multidisciplinary review of rare earth chemistry, geology, beneficiation, industrial applications and marketing. Papers by experts in many fields were presented on the following topics: chemical properties of the rare earth elements; the analysis of rare earth elements and minerals; beneficiation and extraction of rare earth elements; economic geochemistry and mineralogy of rare earths; present industrial uses of rare earth elements; the role of rare earth elements in high-temperature superconductors; the technical application of high-temperature superconductors; supply and demand for rare earth products - now and in the future, and the geology of rare earth deposits

  12. Systematics of triaxial deformation in Xe, Ba, and Ce nuclei

    International Nuclear Information System (INIS)

    Yan, J.; Vogel, O.; von Brentano, P.; Gelberg, A.

    1993-01-01

    The (β,γ) deformation parameters of even-even Xe, Ba, and Ce nuclei have been calculated by using the triaxial rotor model. Deformation parameters calculated, on one hand, from decay properties and, on the other hand, from energies are in good agreement. The smooth dependence of the deformation parameters on Z and N is discussed. The results are compared with those extracted from properties of odd-A nuclei

  13. Cold transfer between deformed, Coulomb excited nuclei

    International Nuclear Information System (INIS)

    Bauer, H.

    1998-01-01

    The scattering system 162 Dy → 116 Sn has been examined at energies in the vicinity of the Coulomb barrier using the Heidelberg-Darmstadt Crystal Ball spectrometer combined with 5 Germanium-CLUSTER detectors. In order to study pairing correlations as a function of angular momentum cold events were selected in the 2n stripping channel by identifying and suppressing the dominant hot part of the transfer with the Crystal Ball. The CLUSTER detectors with their high γ-efficiency were used to identify the transfer channel and to resolve individual final states. Cross sections for the population of individual yrast states in a cold transfer reaction have been measured for the first time indicating the strong influence of higher transfer multipolarities. At small surface distances Coulomb-nuclear interferences were found to be responsible for the stronger decline of the population of higher yrast states in the transfer channel as compared to the Coulex channel. As a preparatory study for 2n transfer measurements between high spin yrast states in the backbending region of deformed nuclei the Coulomb excitation process in the crossing region of two bands in 162 Dy has been analyzed. The gross properties of the measured population probabilities could be interpreted in a simple band mixing model. (orig.)

  14. Quadrupole deformation and clusterization in nuclei

    International Nuclear Information System (INIS)

    Cseh, J.; Algora, A.; Darai, J.; Hess, P.O.

    2004-01-01

    in the dinuclear system model, or in the local potential approach. On the other hand the treatment of the exclusion- principle has to be done microscopically, there- fore, apart from the light, or simplest heavy nuclei, it gives rise to very big computational difficulties. Due to this fact no systematic studies has been done, and many of the experimentally interesting systems are untouched from this viewpoint. The main point of our work is that we present a method for the approximative treatment of the exclusion principle, which can be applied both to binary and ternary (and even to multi) cluster-configurations, and we combine this microscopic approach with an empirical method of the calculation of the energetic preference. This latter quantity is obtained in a similar way as in the work with a straightforward generalisation for ternary clusterization. In this way both aspects of the clusterization (i.e. energy-minimum and exclusion principles) can be handled, therefore, their interrelation can be studied in specific problems. The exclusion-principle is taken into account by a selection rule, based on the real or effective U(3) symmetry for light and heavy nuclei, respectively. This symmetry-based consideration can also be very involved for heavy nuclei, nevertheless, it seems to be widely applicable. As specific examples we consider binary and ternary cluster-configurations in the ground, superdeformed and hyperdeformed states of the light 36 Ar and heavy 252 Cf nuclei. In case of 36 Ar the superdeformed state has been found experimentally, and a theoretical prediction is available for its hyperdeformed state. In case of 252 Cf the main motivation is provided by the spontaneous fission experiments from its ground state, which indicated several very exotic clusterizations. As for superdeformed and hyperdeformed states of this nucleus, we consider hypothetical states with appropriate deformations (ε = 0.6 and ε = 0.86 respectively). The main conclusions of our

  15. Analysis of Orientation Relations Between Deformed Grains and Recrystallization Nuclei

    DEFF Research Database (Denmark)

    West, Stine S.; Winther, Grethe; Juul Jensen, Dorte

    2011-01-01

    Nucleation in 30 pct rolled high-purity aluminum samples was investigated by the electron backscattering pattern method before and after annealing. A total of 29 nuclei including two twins were observed, and approximately one third of these nuclei had orientations not detected in the deformed state....... Possible orientation relations between these nuclei and the deformed state were by 20 to 55 deg rotation around axes. These axes were compared with the active slip systems, and the crystallographic features of the deformation-induced dislocation boundaries. Good agreement was found between the rotation...

  16. Level densities in rare earth nuclei

    International Nuclear Information System (INIS)

    Siem, S.; Tveter, T.S.; Bergholt, L.; Guttormsen, M.; Melby, E.; Rekstad, J.

    1997-01-01

    An iterative procedure for simultaneous extraction of fine structure in the level density and the γ-ray strength function from a set of primary γ-ray spectra has been developed. Data from the reactions 163 Dy(3He,αγ) 172 Dy and 173 Yb(3He,αγ) 172 Yb reveals step like enhancements in the level density in the region below 5 MeV and peaks in the γ-ray strength function at low γ-energy (E γ ∼ 2 - 3.5 MeV). Tentative physical interpretations are presented. (author)

  17. Rare Earth Garnet Selective Emitter

    Science.gov (United States)

    Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

    1994-01-01

    Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approx. = 0.75, sup 4)|(sub 15/2) - (sup 4)|(sub 13/2),for Er-YAG and epsilon(sub lambda) approx. = 0.65, (sup 5)|(sub 7) - (sup 5)|(sub 8) for Ho-YAG) at 1500 K. In addition, low out-of-band spectral emittance, epsilon(sub lambda) less than 0.2, suggest these materials would be excellent candidates for high efficiency selective emitters in thermophotovoltaic (TPV) systems operating at moderate temperatures (1200-1500 K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. Selective emitters in the near IR are of special interest for thermophotovoltaic (TPV) energy conversion. The most promising solid selective emitters for use in a TPV system are rare earth oxides. Early spectral emittance work on rare earth oxides showed strong emission bands in the infrared (0.9 - 3 microns). However, the emittance outside the emission band was also significant and the efficiency of these emitters was low. Recent improvements in efficiency have been made with emitters fabricated from fine (5 - 10 microns) rare earth oxide fibers similar to the Welsbach mantle used in gas lanterns. However, the rare earth garnet emitters are more rugged than the mantle type emitters. A thin film selective emitter on a low emissivity substrate such as gold, platinum etc., is rugged and easily adapted to a wide variety of thermal sources. The garnet structure and its many subgroups have been successfully used as hosts for rare earth ions, introduced as substitutional

  18. Rare earths: occurrence, production and applications

    International Nuclear Information System (INIS)

    Murthy, T.K.S.; Mukherjee, T.K.

    2002-01-01

    The mining and processing of rare earth minerals, particularly of monazite, began in a modest way in 1880s for commercialized production of mantle for gas lighting. For all major applications up to mid-twentieth century- production of lighter flints, misch metal as a metallurgical alloying agent, colouring, decolourizing and polishing agents for glass, petroleum cracking catalysts and arc-carbons, unseparated or partially separated rare earths were adequate. These applications continue till today. With the development and industrial application of powerful techniques like ion exchange and solvent extraction for the separation of rare earths, the decades after 1960 saw increasing utilization of the specific properties of the individual rare earths. Some of these advanced technological applications include: special glass for optical systems including camera lenses, phosphors for colour television, cathode ray tubes and fluorescent lighting, X-ray intensification screens, high intensity permanent magnets, electro optical devices, lasers, hydrogen storage materials, hydride rechargeable batteries, photomagnetic data storage systems, autoexhaust catalysts, special ceramics of unusual toughness, artificial diamonds and nonpoisonous plastic colorants. The topics covered in the book include rare earths: their story identity, rare earth resources, processing of ores and recovery of mixed rare earths products, separation and purification of rare earths, nonmetallic applications of rare earths, rare earth metals: production and applications, rare earth alloys and their applications, analysis of rare earth, processing of rare earth resources in India by Indian Rare Earth Ltd. and availability and market conditions

  19. Strong electric and magnetic dipole excitations in deformed nuclei

    International Nuclear Information System (INIS)

    Kneissl, U.

    1993-01-01

    Systematic nuclear resonance fluorescence (NRF) experiments have been performed at the bremsstrahlung facility of the Stutgart dynamitron to investigate the distribution of magnetic and electric dipole excitations in deformed nuclei

  20. Rare earth industries: Upstream business

    International Nuclear Information System (INIS)

    2011-01-01

    Evidently, many factors contribute to the rush to invest in the unprecedented revival of rare earths. One major reason has to do with the rapidly growing world demand. The other reason relates to the attractive price of rare earths which is projected to stay strong in the coming years. This is because supply is predicted to have difficulty keeping pace with demand. Experts believe a major driver of global rare earths demand is the forecasted expansion in the green economy. Climate change is a major driver of the green economy. With climate change, there is concern that the uncontrolled emission of the greenhouse gases, especially carbon dioxide, can lead to catastrophic consequences for the world. This has been documented in countless studies and reports. Another important driver of the green economy is the growing shortfall in many resources. The world is now experiencing declines in key resources to meet a growing global demand. With more than 6 billion people now in the world and growing, the pressure exerted on global resources including energy, water and food is a major concern. Recent demand surge in China and India has dented the supply position of major world resources. The much quoted Stern Report from the UK has warned that, unless immediate steps are taken to reduce greenhouse gas emissions, it may be a costly exercise to undertake the corrections later. Since energy use, especially fossil fuels, is a major contributor to climate change, greener options are being sought. Add to that the fact that the fossil energy resources of the world are declining, the need to seek alternatives becomes even more urgent. One option is to change to renewable energy sources. These include such potentials as solar, wind and biomass. Rare earths have somehow become a critical feature of the technologies in such renewable. Another option is to improve the efficient use of energy in transport, buildings and all the other energy intensive industries. Again the technologies in

  1. Deformation and shape coexistence in medium mass nuclei

    International Nuclear Information System (INIS)

    Meyer, R.A.

    1985-01-01

    Emerging evidence for deformed structures in medium mass nuclei is reviewed. Included in this review are both nuclei that are ground state symmetric rotors and vibrational nuclei where there are deformed structures at excited energies (shape coexistence). For the first time, Nilsson configurations in odd-odd nuclei within the region of deformation are identified. Shape coexistence in nuclei that abut the medium mass region of deformation is also examined. Recent establishment of a four-particle, four-hole intruder band in the double subshell closure nucleus 96 Zr 56 is presented and its relation to the nuclear vibron model is discussed. Special attention is given to the N=59 nuclei where new data have led to the reanalysis of 97 Sr and 99 Zr and the presence of the [404 9/2] hole intruder state as isomers in these nuclei. The low energy levels of the N=59 nuclei from Z=38 to 50 are compared with recent quadrupole-phonon model calculations that can describe their transition from near-rotational to single closed shell nuclei. The odd-odd N=59 nuclei are discussed in the context of coexisting shape isomers based on the (p[303 5/2]n[404 9/2])2 - configuration. Ongoing in-beam (t,p conversion-electron) multiparameter measurements that have led to the determination of monopole matrix elements for even-even 42 Mo nuclei are presented, and these are compared with initial estimates using IBA-2 calculations that allow mixing of normal and cross subshell excitations. Lastly, evidence for the neutron-proton 3 S 1 force's influence on the level structure of these nuclei is discussed within the context of recent quadrupole-phonon model calculations. (Auth.)

  2. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  3. Rare earth niobate coordination polymers

    Science.gov (United States)

    Muniz, Collin N.; Patel, Hiral; Fast, Dylan B.; Rohwer, Lauren E. S.; Reinheimer, Eric W.; Dolgos, Michelle; Graham, Matt W.; Nyman, May

    2018-03-01

    Rare-earth (RE) coordination polymers are infinitely tailorable to yield luminescent materials for various applications. Here we described the synthesis of a heterometallic rare-earth coordination compound ((CH3)2SO)3(RE)NbO(C2O4)3((CH3)2SO) = dimethylsulfoxide, DMSO, (C2O2= oxalate), (RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb). The structure was obtained from single crystal X-ray diffraction of the La analogue. The Nb˭O and DMSO terminal-bonding character guides assembly of an open framework structure with noncentrosymmetric RE-coordination geometry, and large spacing between the RE centers. A second structure was observed by PXRD for the smaller rare earths (Dy, Ho, Er, Yb); this structure has not yet been determined. The materials were further characterized using FTIR, and photoluminescence measurements. Characteristic excitation and emission transitions were observed for RE = Nd, Sm, Eu, and Tb. Quantum yield (QY) measurements were performed by exciting Eu and Tb analoges at 394 nm (QY 66%) and 464 nm (QY 71%) for Eu; and 370 nm (QY=40%) for Tb. We attribute the high QY and bright luminescence to two main structure-function properties of the system; namely the absence of water in the structure, and absence of concentration quenching.

  4. Rare earth industry in India

    International Nuclear Information System (INIS)

    Singh, D.S.

    2016-01-01

    Rare Earths (RE) comprises of 17 elements i.e. elements from atomic No. 57-71 (lanthanide series) along with yttrium (atomic No. 39) and scandium (atomic No. 21). They exhibit special electronic, magnetic, optical and catalytic properties. The first 7 elements in the lanthanide series from atomic Nos. 57 to 63 (La to Eu) are called Light Rare Earths (LRE), while the remaining elements from atomic Nos. 64 to 71 (Gd to Lu) are grouped as Heavy Rare Earths (HRE). Scandium and Yttrium have properties similar to HRE. The concentration of the REs in the earth's crust is as high as some other elements including that of copper. The only difference is that REs do not occur as separate minerals amenable for easy exploration and mining and are widely distributed across the earth's surface, hence they are called as REs. Resources In India, monazite has been the principal source of RE. It occurs in association with other heavy minerals, such as ilmenite, rutile, zircon etc. in the beach sands and inland placer deposits. The monazite content in this assemblage varies from negligible quantity to as high as 5%. As per AMD resource estimation, the reported resource of monazite in India is about 11.93 million tons which corresponds with about 6.9 million tons of RE oxides. Although India possesses large deposits of monazite, the heavier RE are not present in sufficient quantities in this mineral. (author)

  5. Metallothermic reduction of rare earth oxides

    International Nuclear Information System (INIS)

    Sharma, R.A.

    1986-01-01

    Rare earth oxides can be reduced to rare earth metals by a novel, high yield, metallothermic process. The oxides are dispersed in a suitable, molten, calcium chloride bath along with sodium metal. The sodium reacts with the calcium chloride to produce calcium metal which reduces the rare earth oxides to rare earth metals. The metals are collected in a discrete layer in the reaction vessel

  6. Rare earth-iron-boron premanent magnets

    International Nuclear Information System (INIS)

    Ghendehari, M.H.

    1988-01-01

    This patent describes a method for producing rare earth-iron-boron permanent magnets containing added rare earth oxide, comprising the steps of: (a) mixing a particulate alloy containing at least one rare earth metal, iron, and boron with at least one particulate rare earth oxide; (b) aligning magnetic domains of the mixture in a magnetic field; (c) compacting the aligned mixture to form a shape; and (d) sintering the compacted shape

  7. E2 and M1 transition strengths in heavy deformed nuclei revisited

    International Nuclear Information System (INIS)

    Draayer, J.P.; Popa, G.; Hirsch, J.G.; Vargas, C.E.

    2003-01-01

    An update on the status of pseudo-SU(3) shell-model calculations in strongly deformed nuclei in the rare earth region is presented. Representative results for energy levels as well as E2 (quadrupole) and M1 (scissors) transitions strengths in 162 Dy (even-even) and 163 Dy (odd-mass) are given. The calculations use realistic single-particle energies and quadrupole-quadrupole and pairing interaction strengths fixed from systematics. The strengths of rotor-like terms included in the Hamiltonian- all small relative to the other terms in the interaction were adjusted to give an overall best fit to the energy spectra. The results present a paradox: for even-even nuclei (integer angular momentum) non-zero pseudo-spin configurations seems to be unimportant while for the odd-mass systems (half-integer angular momentum) pseudo-spin mixing is essential as spin-flip couplings appear to dominate the M1 transition strengths. (Author)

  8. The Chinese Society of Rare Earth is Studying The Feasibility of Marketing Rare Earth Futures

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Lin Donglu,secretary-general of the Chinese Society of Rare Earth recently said,the Chinese Society of Rare Earth undertook the research on subject of the National Social Science Fund Foundation on the reform of Chinese rare earth trading pricing mechanism on promoting RMB globalization,and is focusing on studying the feasibility of marketing rare earth futures variety.

  9. Rare earth elements: end use and recyclability

    Science.gov (United States)

    Goonan, Thomas G.

    2011-01-01

    Rare earth elements are used in mature markets (such as catalysts, glassmaking, lighting, and metallurgy), which account for 59 percent of the total worldwide consumption of rare earth elements, and in newer, high-growth markets (such as battery alloys, ceramics, and permanent magnets), which account for 41 percent of the total worldwide consumption of rare earth elements. In mature market segments, lanthanum and cerium constitute about 80 percent of rare earth elements used, and in new market segments, dysprosium, neodymium, and praseodymium account for about 85 percent of rare earth elements used. Regardless of the end use, rare earth elements are not recycled in large quantities, but could be if recycling became mandated or very high prices of rare earth elements made recycling feasible.

  10. Study of Triaxial deformation variable γ in even - even nuclei

    International Nuclear Information System (INIS)

    Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Sharma, Aparna; Varshney, A.K.; Singh, M.; Gupta, D.K.; Varshney, Mani; Dhiman, S.K.

    2011-01-01

    The deformation parameters β and γ of the collective model are basic description of the nuclear equilibrium shape and structure, while values for these variables have been discussed for many nuclei. A systematic study in mass region A = 120-140 and A = 150 -180 can never be less revealing, such study has been presented, in A = 90 -120 for Mo, Ru and Pd nuclei where β and γ both vary strongly

  11. Rotational states in deformed nuclei: An analytic approach

    International Nuclear Information System (INIS)

    Bentz, W.; Arima, A.; Enders, J.; Wambach, J.; Richter, A.

    2011-01-01

    The consequences of the spontaneous breaking of rotational symmetry are investigated in a field theory model for deformed nuclei, based on simple separable interactions. The crucial role of the Ward-Takahashi identities in describing the rotational states is emphasized. We show explicitly how the rotor picture emerges from the isoscalar Goldstone modes and how the two-rotor model emerges from the isovector scissors modes. As an application of the formalism, we discuss the M1 sum rules in deformed nuclei and make the connection to empirical information.

  12. Fine structure in deformed proton emitting nuclei

    International Nuclear Information System (INIS)

    Sonzogni, A. A.; Davids, C. N.; Woods, P. J.; Seweryniak, D.; Carpenter, M. P.; Ressler, J. J.; Schwartz, J.; Uusitalo, J.; Walters, W. B.

    1999-01-01

    In a recent experiment to study the proton radioactivity of the highly deformed 131 Eu nucleus, two proton lines were detected. The higher energy one was assigned to the ground-state to ground-state decay, while the lower energy, to the ground-state to the 2 + state decay. This constitutes the first observation of fine structure in proton radioactivity. With these four measured quantities, proton energies, half-life and branching ratio, it is possible to determine the Nilsson configuration of the ground state of the proton emitting nucleus as well as the 2 + energy and nuclear deformation of the daughter nucleus. These results will be presented and discussed

  13. Gamma band odd-even staggering in some deformed nuclei

    International Nuclear Information System (INIS)

    Khairy, M.K.; Talaat, SH.M.; Morsy, M.

    2005-01-01

    A complete investigation was carried out in studying the odd-even staggering (OES) of gamma bands energy levels in some deformed nuclei up to angular momentum L=13 . With the help of Minkov treatment in the framework of a collective Vector Boson Model (VBM) with broken SU (3) symmetry. The OES behavior of deformed isotopes 162 E r, 164 E r, 166 E r, 156 G d, 170 Y b and 232 T h was studied and discussed

  14. Dynamic deformation theory of spherical and deformed light and heavy nuclei with A = 12-240

    International Nuclear Information System (INIS)

    Kumar, Krishna.

    1979-01-01

    Deformation dependent wave functions are calculated for different types of even-even nuclei (spherical, transitional, deformed; light, medium, heavy) without any fitting parameters. These wave functions are employed for the energies, B(E2)'s, quadrupole and magnetic moments of selected nuclei with A = 12-240 (with special emphasis on 56 Fe, 154 Gd), and for neutron cross sections of 148 Sm, 152 Sm

  15. Raman scattering of rare earth hexaborides

    International Nuclear Information System (INIS)

    Ogita, Norio; Hasegawa, Takumi; Udagawa, Masayuki; Iga, Fumitoshi; Kunii, Satoru

    2009-01-01

    Raman scattering spectra were measured for the rare-earth hexaborides RB 6 (R = Ce, Gd, or Dy). All Raman-active phonons due to B 6 vibrations were observed in the range 600 - 1400 cm -1 . Anomalous peaks were detected below 200 cm -1 , which correspond to vibrations of rare-earth ion excited by second-order Raman scattering process. The intensity and energy of the rare-earth mode decrease with decreasing temperature. This suggests that the rare-earth ion vibrates in a shallow and anharmonic potential due to the boron cage. Using the reported values of mean square displacement of rare-earth ion, we estimated the anharmonic contribution for the rare-earth vibrations.

  16. Rare earth metals for automotive exhaust catalysts

    International Nuclear Information System (INIS)

    Shinjoh, Hirohumi

    2006-01-01

    The usage of rare earth metals for automotive exhaust catalysts is demonstrated in this paper. Rare earth metals have been widely used in automotive catalysts. In particular, three-way catalysts require the use of ceria compounds as oxygen storage materials, and lanthana as both a stabilizer of alumina and a promoter. The application for diesel catalysts is also illustrated. Effects of inclusion of rare earth metals in automotive catalysts are discussed

  17. Rare earth industries: Strategies for Malaysia

    International Nuclear Information System (INIS)

    2011-01-01

    Evidently, many reports cite Malaysia as having reasonably substantial amounts of rare earths elements. In fact, based on the rare earths found in the residual tin deposits alone, Malaysia has about 30,000 tonnes. This does not take into account unmapped deposits which experts believe may offer more tonnages of rare earths. Brazil which is reported to have about 48,000 tonnes has announced plans to invest aggressively in the rare earths business. China has on record the largest reserves with about 36 million tonnes. This explains why China has invested heavily in the entire value chain of the rare earths business. Chinas committed investment in rare earths started many years ago when the country's foremost leaders proclaimed the strategic position of rare earths in the world economy. That forecast is now a reality where the rise in the green high-tech economy is seen driving global demand for rare earths in a big way. Malaysia needs to discover and venture into new economic growth areas. This will help fuel the country's drive to achieve a high income status by 2020 as articulated in the New Economic Model (NEM) and the many supporting Economic Transformation Plans that the Government has recently launched. Rare earths may be the new growth area for Malaysia. However, the business opportunities should not just be confined to the mining, extraction and production of rare earths elements alone if Malaysia is to maximise benefits from this industry. The industry's gold mine is in the downstream products. This is also the sector that China wants to expand. Japan which now controls about 50 % of the global market for downstream rare earths-based high-tech components is desperately looking for partners to grow their stake in the business. Malaysia needs to embark on the right strategies in order to build the rare earths industry in the country. What are the strategies? (author)

  18. Rare earth - no case for government intervention

    OpenAIRE

    Georg Zachmann

    2010-01-01

    China has officially restricted exports of rare earth for several years and announced this year it will further tighten exports. Rare earth is a group of 17 different metals, usually found clustered together. These metals have hundreds of different industry applications. For example, they are used in certain high capacity magnets, batteries and lasers. As the rare earth elements are used in sectors that are assumed to have an over-proportionate growth potential (eg. green-technology), policy ...

  19. Octupole Deformed Nuclei in the Actinide Region

    CERN Multimedia

    Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I

    2002-01-01

    The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ -decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.

  20. E2 transitions in deformed nuclei and the IBA

    International Nuclear Information System (INIS)

    Warner, D.D.; Casten, R.F.

    1981-01-01

    The mechanism which determines the relative E2 strengths in the Interacting Boson Approximation is studied, and the structure of the E2 operator necessary to reproduce the empirical B(E2) values in deformed even-even nuclei in the rate earth region is investigated

  1. Alaska's rare earth deposits and resource potential

    Science.gov (United States)

    Barker, James C.; Van Gosen, Bradley S.

    2012-01-01

    Alaska’s known mineral endowment includes some of the largest and highest grade deposits of various metals, including gold, copper and zinc. Recently, Alaska has also been active in the worldwide search for sources of rare earth elements (REE) to replace exports now being limitedby China. Driven by limited supply of the rare earths, combined with their increasing use in new ‘green’ energy, lighting, transportation, and many other technological applications, the rare earth metals neodymium, europium and, in particular, the heavy rare earth elements terbium, dysprosium and yttrium are forecast to soon be in critical short supply (U.S. Department of Energy, 2010).

  2. Relativistic mean field theory for deformed nuclei with pairing correlations

    International Nuclear Information System (INIS)

    Geng, Lisheng; Toki, Hiroshi; Sugimoto, Satoru; Meng, Jie

    2003-01-01

    We develop a relativistic mean field (RMF) description of deformed nuclei with pairing correlations in the BCS approximation. The treatment of the pairing correlations for nuclei whose Fermi surfaces are close to the threshold of unbound states needs special attention. With this in mind, we use a delta function interaction for the pairing interaction to pick up those states whose wave functions are concentrated in the nuclear region and employ the standard BCS approximation for the single-particle states obtained from the BMF theory with deformation. We apply the RMF + BCS method to the Zr isotopes and obtain a good description of the binding energies and the nuclear radii of nuclei from the proton drip line to the neutron drip line. (author)

  3. Some aspects of reflection asymmetric deformations in nuclei

    International Nuclear Information System (INIS)

    Olanders, P.

    1984-10-01

    The nuclear shape in the intrinsic frame is studied using the Strutinsky method. Various potentials (Nilsson, folded Yukawa and Woods-Saxon) are used for the microscopic part, and the macroscopic part is described as a liquid drop with either a sharp or a smooth surface. Special attention is paid to the possibility of octupole deformed ground states. The consequences of octupole deformations for the rotational behaviour are investigated using the cranking model. It is particularly shown that octupole deformation may supress the backbending in some nuclei. (author)

  4. Rotational states of odd Z rare earth proton emitter 131Eu

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2013-01-01

    Recent observation of proton radioactivity and rotational bands in 131 Eu and 141 Ho with large deformations β ≈ 0.3 and γ softness have already proven the study of excited states of deformed proton emitters a source of valuable information on the structure of proton decaying states and response of proton emitters on the stress of rotation. The rare earth nuclei below the N = 82 shell closure form one of the few regions of the nuclear chart where nuclear shapes are expected to change rapidly with coexistence of oblate and prolate shapes in some nuclei. We evaluate shapes and deformation of 131 Eu by combining classical collective properties of the liquid drop model with the quantum corrections due to shell effects via Strutinsky formalism adequately described in. Excited states are treated using statistical theory. Nuclear shapes and deformation are traced by minimizing free energy (F = E-TS) w.r.t. deformation parameters β from 0 to 0.4 in steps of 0.01 and γ from -180° (oblate with symmetry axis parallel to the rotation axis) to -120° (prolate with symmetry axis perpendicular to rotation axis) and then to -60° (oblate collective) to 0° (prolate non-collective)

  5. Recycling of Rare Earth Elements

    Science.gov (United States)

    Lorenz, Tom; Bertau, Martin

    2017-01-01

    Any development of an effective process for rare earth (RE) recycling has become more and more challenging, especially in recent years. Since 2011, when commodity prices of REs had met their all-time maximum, prices have dropped rapidly by more than 90 %. An economic process able to offset these fluctuations has to take unconventional methods into account beside well-known strategies like acid/basic leaching or solvent extraction. The solid-state chlorination provides such an unconventional method for mobilizing RE elements from waste streams. Instead of hydrochloric acid this kind of chlorination decomposes NH4Cl thermally to release up to 400 °C hot HCl gas. After cooling the resulting solid metal chlorides may be easily dissolved in pH-adjusted water. Without producing strongly acidic wastes and with NH4Cl as cheap source for hydrogen chloride, solid-state chlorination provides various advantages in terms of costs and disposal. In the course of the SepSELSA project this method was examined, adjusted and optimized for RE recycling from fluorescent lamp scraps as well as Fe14Nd2B magnets. Thereby many surprising influences and trends required various analytic methods to examine the reasons and special mechanisms behind them.

  6. Chemical analysis of rare earth elements

    International Nuclear Information System (INIS)

    Tsukahara, Ryoichi; Sakoh, Takefumi; Nagai, Iwao

    1994-01-01

    Recently attention has been paid to ICP-AES or ICP-MS, and the reports on the analysis of rare earth elements by utilizing these methods continue to increase. These reports have become to take about 30% of the reports on rare earth analysis, and this is because these methods are highly sensitive to rare earth elements, and also these methods have spread widely. In ICP-AES and ICP-MS, mostly solution samples are measured, therefore, solids must be made into solution. At the time of quantitatively determining the rare earth elements of low concentration, separation and concentration are necessary. Referring to the literatures reported partially in 1990 and from 1991 to 1993, the progress of ICP-AES and ICP-MS is reported. Rare earth oxides and the alloys containing rare earth elements are easily decomposed with acids, but the decomposition of rocks is difficult, and its method is discussed. The separation of the rare earth elements from others in geochemical samples, cation exchange process is frequently utilized. Also solvent extraction process has been studied. For the separation of rare earth elements mutually, chromatography is used. The spectral interference in spectral analysis was studied. The comparison of these methods with other methods is reported. (K.I)

  7. Rare earth oxyhydrides and preparation process

    International Nuclear Information System (INIS)

    Diaz, H.

    1986-01-01

    Rare earth oxyhydrides of formula RE 1-q Th q Ni 5-p M p O x H y are claimed. RE is a rare earth, Th can be replaced by Yt, M is Cu, Mn, Al, Fe, Cr or Co, o O C and the hydrides are oxidized. They are catalysts for various chemical reactions [fr

  8. Process for lead removal from rare earth

    International Nuclear Information System (INIS)

    Bollat, A.; Sabot, J.L.

    1987-01-01

    An aqueous solution of rare earth chlorides and lead chlorides, with a chloride concentration of at least 2 moles/liter and a pH between 2 and 4, is extracted by an alkylphosphonic acid ester and rare earth(s) is (are) recovered from the organic phase [fr

  9. Theory of Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1977-01-01

    A mean-field random alloy theory combined with a simple calculation of the exchange interaction J(c,Q) is shown to quantitatively account for the phase diagrams for alloys of rare-earth metals with Y, Lu, Sc, and other rare-earth metals. A concentration-dependent J(c,Q) explains the empirical 2...

  10. Rare Earth Elements Distribution in Beryl

    International Nuclear Information System (INIS)

    El Gawish, H.K.; Nada, N.; Ghaly, W.A.; Helal, A.I.

    2012-01-01

    Laser ablation method is applied to a double focusing inductively coupled plasma mass spectrometer to determine the rare earth element distribution in some selected beryl samples. White, green and blue beryl samples are selected from the Egyptian eastern desert. Distributions of chondrite- normalized plot for the rare earth element in the selected beryl samples are investigated

  11. Rare earths and rare earth alloys electrolytic preparation process and device for this process

    International Nuclear Information System (INIS)

    Seon, F.; Barthole, G.

    1986-01-01

    Electrolysis of a molten salt of rare earth or rare earth alloy for preparation of the metal or alloy is described. The molten salt bath comprises at least a rare earth chloride, at least an alkaline or alkaline earth chloride and at least an alkaline or alkaline earth fluoride [fr

  12. Rare Earth Metals: Resourcefulness and Recovery

    Science.gov (United States)

    Wang, Shijie

    2013-10-01

    When we appreciate the digital revolution carried over from the twentieth century with mobile communication and the Internet, and when we enjoy our high-tech lifestyle filled with iDevices, hybrid cars, wind turbines, and solar cells in this new century, we should also appreciate that all of these advanced products depend on rare earth metals to function. Although there are only 136,000 tons of annual worldwide demand, (Cho, Rare Earth Metals, Will We Have Enough?)1 rare earth metals are becoming such hot commodities on international markets, due to not only to their increasing uses, including in most critical military hardware, but also to Chinese growth, which accounts for 95% of global rare earth metal production. Hence, the 2013 technical calendar topic, planned by the TMS/Hydrometallurgy and Electrometallurgy Committee, is particularly relevant, with four articles (including this commentary) contributed to the JOM October Issue discussing rare earth metals' resourcefulness and recovery.

  13. Collisions of deformed nuclei and superheavy-element production

    International Nuclear Information System (INIS)

    Iwamoto, Akira; Moeller, P.; Univ. of Aizu, Fukushima; P. Moller Scientific Computing and Graphics, Inc., Los Alamos, NM; Los Alamos National Lab., NM; Nix, J.R.; Sagawa, Hiroyuki, Sagawa

    1995-01-01

    A detailed understanding of complete fusion cross sections in heavy-ion collisions requires a consideration of the effects of the deformation of the projectile and target. The aim here is to show that deformation and orientation of the colliding nuclei have a very significant effect on the fusion-barrier height and on the compactness of the touching configuration. To facilitate discussions of fusion configurations of deformed nuclei, the authors develop a classification scheme and introduce a notation convention for these configurations. They discuss particular deformations and orientations that lead to compact touching configurations and to fusion-barrier heights that correspond to fairly low excitation energies of the compound systems. Such configurations should be the most favorable for producing superheavy elements. They analyze a few projectile-target combinations whose deformations allow favorable entrance-channel configurations and whose proton and neutron numbers lead to compound systems in a part of the superheavy region where a half-lives are calculated to be observable, that is, longer than 1 micros

  14. Relativistic quasiparticle random phase approximation in deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pena Arteaga, D.

    2007-06-25

    Covariant density functional theory is used to study the influence of electromagnetic radiation on deformed superfluid nuclei. The relativistic Hartree-Bogolyubov equations and the resulting diagonalization problem of the quasiparticle random phase approximation are solved for axially symmetric systems in a fully self-consistent way by a newly developed parallel code. Three different kinds of high precision energy functionals are investigated and special care is taken for the decoupling of the Goldstone modes. This allows the microscopic investigation of Pygmy and scissor resonances in electric and magnetic dipole fields. Excellent agreement with recent experiments is found and new types of modes are predicted for deformed systems with large neutron excess. (orig.)

  15. Collective two-phonon states in deformed nuclei

    International Nuclear Information System (INIS)

    Solov'ev, V.G.; Shirikova, N.Y.

    1982-01-01

    The Pauli principle in the two-phonon components of the wave functions is taken into account within the framework of the quasiparticle-phonon model of the nucleus with phonon operators depending on the sign of the projection of the angular momentum. The centroid energies of collective two-phonon states in even-even deformed nuclei are calculated and it is shown that the inclusion of the Pauli principle shifts them by 1--3 MeV to higher energies. The shifts of the three-phonon poles due to the inclusion of the Pauli principle in the three-phonon components of the wave functions are calculated. Strong fragmentation of collective two-phonon states whose energy centroids are 3--5 MeV should be expected. It is concluded that collective two-phonon states need not exist in deformed nuclei. The situation with the 168 Er nucleus and the Th and U isotopes is analyzed

  16. Situation with collective two-phonon states in deformed nuclei

    International Nuclear Information System (INIS)

    Soloviev, V.G.; Shirikova, N.Yu.

    1982-01-01

    Within the quasiparticle-phonon nuclear model with the operators of phonons depending on the sign of the angular momentum projection, the Pauli principle is taken into account in the two-phonon components of the wave functions. The centroid energies of the collective two-phonon states in even-even deformed nuclei are calculated. It is shown that the inclusion of the Pauli principle leads to their shift by 1-3 MeV towards high energies. The shifts of three-phonon poles due to the Pauli principle are calculated in the three-phonon components of the wave functions. The collective two-phonon states, the centroid energies of which are 3-5 MeV, are expected to be strongly fragmented. The conclusion is confirmed that the collective two-phonon states should not exist in deformed nuclei. The situation in 168 Er and in the 228 Th isotopes is analysed

  17. Thermochemistry of rare-earth trifluorides

    International Nuclear Information System (INIS)

    Kim, K.Y.; Johnson, C.E.

    1981-01-01

    Using the most recent crystallographic data, the Born-Lande equation was employed to calculate lattice energies of the rare-earth trifluorides. The excellent agreement ( 0 sub(f)(MX 3 ,c,298.15K) can be estimated. The magnitude of the monotonic change of ΔH 0 sub(f)(MX 3 ) for the rare-earth trihalides series (14 4f electrons) is comparable to the energy change between Sc and Ti in which only one 3d electron is added. This energy change is consistent with the chemical evidence that the electrons in the f-orbitals of rare earths contribute negligibly to the bonding. (author)

  18. Recovery of rare earths from red mud

    International Nuclear Information System (INIS)

    Bautista, R.G.

    1992-01-01

    The prospect for the recovery of rare earths from red mud, the bauxite tailings from the production of alumina is examined. The Jamaican red mud by far has the higher trace concentrations of lanthanum, cerium, neodymium, and yttrium. Scandium is also present. The dissolution of the rare earth is a major extraction problem because of the large volume of other materials. The recovery processes that have been proposed include the production of co-products such as iron, alumina, and titanium concentrates, with the rare earths going with the titanium. In this paper a critical examination of the possible processes are presented with the recommended research projects to be carried out

  19. Ground state properties of exotic nuclei in deformed medium mass region

    International Nuclear Information System (INIS)

    Manju; Chatterjee, R.; Singh, Jagjit; Shubhchintak

    2017-01-01

    The dipole moment, size of the nucleus and other ground state properties of deformed nuclei 37 Mg and 31 Ne are presented. Furthermore with this deformed wave function the electric dipole strength distribution for deformed nuclei 37 Mg and 31 Ne is calculated. This will allow us to investigate the two dimensional scaling phenomenon with two parameters: quadrupole deformation and separation energy

  20. State of rare earth impurities in gallium and indium antimonides

    International Nuclear Information System (INIS)

    Evgen'ev, S.B.; Kuz'micheva, G.M.

    1990-01-01

    State of rare earth impurities in indium and gallium antimonides was studied. Results of measuring density and lattice parameter of samples in GaSb-rare earth and InSb-rare earth systems are presented. It is shown that during rare earth dissolution in indium and gallium antimonides rare earth atoms occupy interstitial positions or, at least, are displaced from lattice points

  1. Shape transition and coexistence in neutron-deficient rare earth isotopes

    CERN Multimedia

    We propose to study spectroscopic quadrupole moments of excited states and electromagnetic transition rates between them in the neutron-deficient rare earth nuclei $^{140}$Sm and $^{142}$Gd using projectile Coulomb excitation at energies of 4.7 MeV per nucleon. The rare earth nuclei below the N=82 shell closure form one of the few regions of the nuclear chart where oblate shapes are expected to occur near the ground state. Nuclear shapes are expected to change rapidly in this region, with coexistence of oblate and prolate shapes in some nuclei. The measurement of electromagnetic matrix elements represents therefore a particularly sensitive test of theoretical nuclear structure models.

  2. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.G.

    1975-01-01

    This patent describes a sintered product having substantially stable permanent magnet properties in air at room temperature. It comprises compacted particulate cobalt--rare earth alloy consisting essentially of a Co 5 R intermetallic phase and a CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase, where R is a rare earth metal. The Co 5 R intermetallic phase is present in an amount of at least 65 percent by weight of the sintered product and the CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase is present in a positive amount having a value ranging up to about 35 percent by weight of the product. The sintered product has a density of at least 87 percent and has pores which are substantially noninterconnecting and wherein the component grains have an average size less than 30 microns

  3. Thermodynamics of rare earths in steelmaking

    International Nuclear Information System (INIS)

    Vahed, A.; Kay, D.A.R.

    1976-01-01

    The standard free energies of formation of the oxides, sulfides and oxysulfides of cerium and lanthanum under steelmaking conditions have been calculated and used to predict the behavior of rare earths in steelmaking. Deoxidation and desulfurization constants, expressed in terms of Henrian activities, have been used to construct a precipitation diagram which indicates the sequence of rare earth inclusion formation. An enrichment of lanthanum in (RE)-oxysulfide and cerium in (RE)-sulfide is predicted. It is also predicted that rare earths should be able to reduce the soluble oxygen and sulfur contents of liquid steel well below the contents presently found in most industrial and laboratory practices. A simple method of calculating steelmaking additions for complete rare earth control of inclusion composition is presented

  4. 12 Ministries Control Rare Earth Exports

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>"It is very natural to reserve rare earth as a strategic resource.Many countries do this,including China."On April 8,Sun Lihui,Vice Director of Metal Section of Chemicals Import & Export Commerce Chamber of China Minmetals Corporation told a reporter that as early as 2006,China has launched a strategic plan for rare earth,"but it was interrupted by the subsequent financial crisis."

  5. 2004 Top 10 Chinese Rare Earth Events

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1. Management to the Investment in Rare Earth IndustryConfirmedIn July 2004, "Decision on the Reform in Investment System" was formally publicized by the State Council of the People's Republic of China. The fifth item in the Decision stipulates that ore exploitation, smelting & separation and rare earth deep-processed projects with total investment over RMB¥100 million should be approved by the investment governing department of the State Council, and that other

  6. Mammography with rare earth intensifying screens

    International Nuclear Information System (INIS)

    Maurer, H.J.; Goos, F.

    1987-01-01

    Screens basing on rare earth phosphors with suitable films green or blue sensitive may be used in mammography with grids without diagnostic losses. Highest definition will be obtained with medium densities on film. High-speed screens may reduce dose, but definition is poor. Best compromise between speed and high definition may be reached with relative low thickness of phosphor layers. A system of high definition films (Medichrome) and special rare earth screens give best results. (orig.) [de

  7. Rare earths refining by vacuum sublimation method

    International Nuclear Information System (INIS)

    Rytus, N.N.

    1983-01-01

    The process of rare earths refining by the sUblimation; method in high and superhigh oil-free vacuum, is investigated. The method is effective for rare earths obtaining and permits to prepare metal samples with a high value of electric resistance ratio γ=RsUb(298 K)/Rsub(4.2 K). The estimation of general purity is performed for Sm, Eu, Yb, Tm, Dy, Ho, Er and Se

  8. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.C.

    1975-01-01

    A process is described for preparing novel sintered cobalt--rare earth intermetallic products which can be magnetized to form permanent magnets having stable improved magnetic properties. A cobalt--rare earth metal alloy is formed having a composition which at sintering temperature falls outside the composition covered by the single Co 5 R intermetallic phase on the rare earth richer side. The alloy contains a major amount of the Co 5 R intermetallic phase and a second solid CoR phase which is richer in rare earth metal content than the Co 5 R phase. The specific cobalt and rare earth metal content of the alloy is substantially the same as that desired in the sintered product. The alloy, in particulate form, is pressed into compacts and sintered to the desired density. The sintered product is comprised of a major amount of the Co 5 R solid intermetallic phase and up to about 35 percent of the product of the second solid CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase

  9. Extraction of rare earths from iron-rich rare earth deposits

    OpenAIRE

    Bisaka, K.; Thobadi, I.C.; Pawlik, C.

    2017-01-01

    Rare earth metals are classified as critical metals by the United Nations, as they have found wide application in the fabrication of magnets, particularly those used in green energy technologies which mitigate global warming. Processing of ores containing rare earth elements is complex, and differs according to the nature of each ore. In the conventional process, run of mine (ROM) ores are processed in a physical separation plant to produce a concentrate from which rare earth elements are ext...

  10. Recovering heavy rare earth metals from magnet scrap

    Science.gov (United States)

    Ott, Ryan T.; McCallum, Ralph W.; Jones, Lawrence L.

    2017-08-08

    A method of treating rare earth metal-bearing permanent magnet scrap, waste or other material in a manner to recover the heavy rare earth metal content separately from the light rare earth metal content. The heavy rare earth metal content can be recovered either as a heavy rare earth metal-enriched iron based alloy or as a heavy rare earth metal based alloy.

  11. Rare earth mobility in hydrothermal ore-forming systems

    International Nuclear Information System (INIS)

    Cornell, D.H.; Schade, J.; Scheepers, R.; Watkeys, M.K.

    1988-01-01

    Rocks and ores which form by magmatic processes display a range of chondrite-normalised rare earth profiles. One REE (rare earth elements) profile feature which seems unrelated to magmatic processes is the birdwing profile, in which both heavy and light rare earths are enriched relative to the middle rare earths. Birdwing rare earth profiles are an easily identified geochemical anomaly. It is proposed that rare earth geochemistry could be applied in geochemical prospecting for ore formed by hydrothermal processes. 5 figs

  12. 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

  13. Rare earths production and marketing opportunities

    International Nuclear Information System (INIS)

    Falconnet, P.G.

    1988-01-01

    The rare earths (RE) market is relatively small. The total production during 1968 was only 10000 tons (REO) which rose to 27000 tons (REO) during 1985. The three major areas of application, which are volume market for ceric rare earths are catalysts, glass ceramics and metallurgy. Among the other uses of rare earths, the permanent magnets, lamp phosphors and fine ceramics have registered significant growth in RE consumption. Monazite and bastnasite are the main natural source for rare earths and processing of these for one of the rare earths in high demand leads to over production of some others not in demand, thus creating a balance problem. The growth in RE market has always been influenced by the technology shifts and product substitution. For example, the RE consumption during 1974/76 for desulfurization of steel had substantially decreased due to the usage of calcium. Similarly, 1985 had witnessed a drastic cut in the use of REs in fluid cracking due to the introduction of stabilized zeolites which contain less REO. Thus, the overall compound growth rate of demand was only 3.9 % per year during the period 1970-1985. At present, 37 % of the rare earths production goes to the glass/ceramics industry, 33 % for catalyst and 25 % to metallurgy. The price of REs constantly shows a downward trend. This trend coupled with the rapid changes taking place in the various technological fields, demands greater flexibility and high marketing skills from the RE producers. The key factor for future expansion of RE market will be the development of 'high volume' application of ceric rare earths. (author) 2 figs., 8 tabs

  14. Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review

    Directory of Open Access Journals (Sweden)

    Sravya Tekumalla

    2014-12-01

    Full Text Available Magnesium-rare earth based alloys are increasingly being investigated due to the formation of highly stable strengthening phases, activation of additional deformation modes and improvement in mechanical properties. Several investigations have been done to study the effect of rare earths when they are alloyed to pure magnesium and other Mg alloys. In this review, the mechanical properties of the previously investigated different magnesium-rare earth based binary alloys, ternary alloys and other higher alloys with more than three alloying elements are presented.

  15. On the role of high multipolarity interactions in deformed nuclei

    International Nuclear Information System (INIS)

    Solov'ev, V.G.; Sushkov, A.V.

    1989-01-01

    The influence of interactions with the multipolarity λ=5,6,7 and 9 is studied on the mixing of two-quasineutron and two-quasineutron states with large K in doubly even deformed nuclei. The mixing of the two-quasineutron and two-quasiproton states with the same values of K π , caused by a high multipolarity interaction, is shown to be large in the case of proximity of their energies. Qualitatively correct description of experimental data on the mixing of two-quasineutron and two-quasiproton configurations in 178,176 Hf, 174 Yb, 168 Er and 158 Gd is obtained. 20 refs.; 1 tab

  16. Survey of odd-odd deformed nuclear spectroscopy

    International Nuclear Information System (INIS)

    Hoff, R.W.

    1993-01-01

    In this paper, we survey the current experimental data that support assignment of rotational bands in odd-odd deformed nuclear in the rare earth and actinide regions. We present the results of a new study of 170 Mt nuclear structure. In a comparing experimental and calculated Gallagher-Moszkowski matrix elements for rare earth-region nuclei, we have developed a new approach to the systematics of these matrix elements

  17. The splitting of giant multipole states of deformed nuclei

    International Nuclear Information System (INIS)

    Suzuki, T.; Rowe, D.J.

    1977-01-01

    A vibrating potential model is applied to deformed nuclei with a deformed harmonic oscillator potential in order to discuss the splitting of isoscalar giant quadrupole states. Eigenfrequencies of the collective states are estimated to be √2ω(1 - delta/3), √2ω(1 - delta/6) and √2ω(1 + delta/3) for K = 0 + ,1 + and 2 + modes, respectively. The splitting of isovector dipole and isovector quadrupole states is also studied according to a schematic model as proposed by Bohr and Mottelson. It is shown that isovector dipole states are split, as in a hydrodynamic model, while isovector quadrupole states with the same scaling factors as those of isocalar quadrupole modes. (Auth.)

  18. Rare earth elements and permanent magnets (invited)

    Science.gov (United States)

    Dent, Peter C.

    2012-04-01

    Rare earth (RE) magnets have become virtually indispensible in a wide variety of industries such as aerospace, automotive, electronics, medical, and military. RE elements are essential ingredients in these high performance magnets based on intermetallic compounds RECo5, RE2TM17 (TM: transition metal), and RE2TM14B. Rare earth magnets are known for their superior magnetic properties—high induction, and coercive force. These properties arise due to the extremely high magnetocrystalline anisotropy made possible by unique 3d-4f interactions between transition metals and rare earths. For more than 40 years, these magnets remain the number one choice in applications that require high magnetic fields in extreme operating conditions—high demagnetization forces and high temperature. EEC produces and specializes in RECo5 and RE2TM17 type sintered magnets. Samarium and gadolinium are key RE ingredients in the powder metallurgical magnet production processes which include melting, crushing, jet milling, pressing, sintering, and heat treating. The magnetic properties and applications of these magnets will be discussed. We will also briefly discuss the past, current, and future of the permanent magnet business. Currently, over 95% of all pure rare earth oxides are sourced from China, which currently controls the market. We will provide insights regarding current and potential new magnet technologies and designer choices, which may mitigate rare earth supply chain issues now and into the future.

  19. Photon strength in spherical and deformed heavy nuclei

    International Nuclear Information System (INIS)

    Grosse, E.; Junghans, A.; Birgersson, E.; Massarczyk, R.; Schramm, G.; Becvar, F.

    2010-01-01

    Information on the photon strength in heavy nuclei with mass A>150 will be given and compared to respective data. The photon strength function is a very important ingredient for statistical model calculations - especially when these are used to describe neutron capture. Several schemes for a transmutation of radioactive waste favor nuclear reactions with fast neutrons and these also influence the performance of various reactor types proposed to deliver nuclear energy together with only small quantities of such waste. Reactions with fast neutrons are far less studied as compared to those induced by thermal neutrons. As they are not easily accessible experimentally, reference is often made to calculations using the statistical model. Photon emission probabilities are needed as input to such calculations aiming for predictions on fission to capture ratios. From the favorable comparison of our parameterization to the experimental data for photon induced as well radiative capture processes in nuclei with various shapes and level densities we conclude what follows. First, the giant dipole resonance has very much the same properties in all heavy nuclei when their deformation is properly accounted for and its spreading width varies only smoothly with the resonance energies E k and not with the photon energy E γ . The radiative neutron capture results presented confirm strength data found in the literature. We also learn that our parameterization is at least a good approximation for photon energies below 4 MeV that dominate this process

  20. Rapid analysis of some rare earth magnets

    International Nuclear Information System (INIS)

    Raoot, K.N.; Raoot, Sarala; Rukmani Desikan, N.

    1978-01-01

    A simple complexometric method for the quick analysis of the constituent elements in some quaternary rare earth magnets of the type RE-Co-Cu-Fe and RE-Ni-Cu-Fe is described. The technique is based on a total titration, subsequent release of EDTA from rare earth with ammonium fluoride and that from copper (II) with ascorbic acid and thiourea followed by determination of the excess and liberated EDTA by lead nitrate in a weak acid medium using xylenol orange indicator. In another, aliquot iron (III) and rare earth are first masked with sodium fluoride, and copper (II) with ascorbic acid and thiourea before cobalt (II) or nickel (II) is estimated by back titration. Iron is calculated by difference. The new method yields accurate and reproducible results with error not exceeding 1%. A set of three samples can conveniently be analysed in two hours. (author)

  1. Coprecipitation of rare earth elements with hydroxyapatite

    International Nuclear Information System (INIS)

    Fujino, Osamu

    1979-01-01

    The distribution behavior of trace rare earth elements between an aqueous phase and hydroxyapatite crystals was investigated. The apatite prepared by adding phosphate ion extremely slowly to an aqueous solution containing calcium, rare earth elements, ethylenediamine and nitrilotriacetate ion at 80 0 C. Apparently the coprecipitation reaction seems to be anomalous, because the apparent distribution coefficient did not have a constant value through the reaction. But when the true distribution coefficient was calculated by using the thermodynamic data at 80 0 C, it was revealed that rare earth ions were coprecipitated obeying logarithmic distribution law. The true distribution coefficient values of trivalent yttrium, scandium, europium and cerium ions were about 10sup(7.3), 10sup(9.8), 10sup(7.4) and 10sup(6.5) respectively. (author)

  2. Rare earths: harvesting basic research for technology

    International Nuclear Information System (INIS)

    Jagatap, B.N.

    2014-01-01

    In recent years, rare earths are increasingly becoming a versatile platform for basic research that presents enormous technological potentials. A variety of nano-sized inorganic matrices varying from oxides, phosphates, gallates and aluminates, tungstates, stannates, vanadates to fluorides doped with different lanthanide ions have been synthesized and their optical properties have been investigated in the Chemistry Group, BARC. Another interesting application is laser cooling of solids using rare earth doped glasses with potential applications in remote cooling of electronic devices. Combining the luminescence properties of rare earths with photonic crystals is yet another potent area with wide ranging applications. In this presentation we provide an overview of these developments with examples from the R and D programs of the Chemistry Group, BARC

  3. Rapid analysis of some rare earth magnets

    Energy Technology Data Exchange (ETDEWEB)

    Raoot, K N; Raoot, S; Rukmani Desikan, N [Defence Metallurgical Research Lab., Hyderabad (India)

    1978-12-01

    A simple complexometric method for the quick analysis of the constituent elements in some quaternary rare earth magnets of the type RE-Co-Cu-Fe and RE-Ni-Cu-Fe is described. The technique is based on a total titration, subsequent release of EDTA from rare earth with ammonium fluoride and that from copper (II) with ascorbic acid and thiourea followed by determination of the excess and liberated EDTA by lead nitrate in a weak acid medium using xylenol orange indicator. In another, aliquot iron (III) and rare earth are first masked with sodium fluoride, and copper (II) with ascorbic acid and thiourea before cobalt (II) or nickel (II) is estimated by back titration. Iron is calculated by difference. The new method yields accurate and reproducible results with error not exceeding 1%. A set of three samples can conveniently be analysed in two hours.

  4. On fluorozirconates and fluorohafnates of rare earths

    International Nuclear Information System (INIS)

    Korenev, Yu.M.; Antipov, P.I.; Novoselova, A.V.

    1980-01-01

    It has been shown by the method of X-ray phase analysis that on interaction between rare-earth fluorides and zirconium and hafnium tetrafluorides, compounds with 1:1, 1:2, 1:3 molar ratios of components are formed. Compounds of the LnHfF 4 type are prepared for all rare-earths. Fluoro-metals of the LnHf 2 F 11 composition are typical only of light lanthanides from lanthanum to neodymium, while pentafluorated salts Ln(EF 5 ) 3 are formed in the reaction between EF 4 with fluorides of heavy rare-earth elements from samarium to lutecium, as well as with yttrium trifluoride. Parameters of unit cells of heptafluohafnates and pentafluometallates are determined

  5. Thermogravimetric study of rare earth concentrates

    International Nuclear Information System (INIS)

    Delyagejd, V.V.; Anisimova, V.N.; Eremenko, Z.V.; Kutsev, V.S.

    1974-01-01

    Methods of thermogravimetric, chemical and phase analysis were used in measuring the concentration of rare-earth elements of different origins. At temperatures 400-800 deg C a gradual decomposition of fluorocarbonates takes place leading to the formation of derivatives of corresponding oxides and oxyfluorides. For concentrates containing siderite the process takes place at 550-600 deg C followed by oxidation of bivalent iron into trivalent state. Reaction of rare-earth elements with sodium carbonate and the increase in the concentration of the latter results in a narrowing down of the interval of temperatures at which decomposition takes place. Under these conditions an intense reaction and a fusion take place leading to the formation of eutectic at 500-600 deg C and further synthesis of sodium fluoride and oxyfluoride derivatives of calcium and rare-earth elements

  6. Nuclear orientation on rare earth nickel alloys

    International Nuclear Information System (INIS)

    Nishimura, K.

    1998-01-01

    A hyperfine interaction study of the light rare earth elements, Ce, Pr, Nd and Pm, in the rare earth nickel and CeNi 2 Al 5 compounds by means of the low temperature nuclear orientation is summarised. The magnitudes and directions of the magnetic hyperfine fields obtained through measurements of γ-ray anisotropy and angular distributions reveal the magnetic structures of the ions. The experiments extracted peculiar results for the magnetic properties of the ions, and show certain novel features of the technique to the study of solid-state magnetism. Copyright (1998) Australian Journal of Physics

  7. Features of rare earth element (3) complexing

    International Nuclear Information System (INIS)

    Martynenko, L.I.

    1991-01-01

    Reasons for nonobeyance to the regularity of tetrad ''W'' effect of rare earth chelate complex compounds are discussed in the review. The concept of metal-ligand ionic bond in rare earth complexes is put in the basis of the consideration. From this viewpoint mutual influence of ligands in lower, higher, polynuclear and different-ligand complexes, formed by the ligands of low, medium and high denticity, is discussed. Problems of intermolecular interaction of complexes with different structure are considered in relation to problems of variation of chelate volatility and selectivity in the processes of sublimation and precipitation

  8. Strength of Coriolis Coupling in actinide nuclei

    International Nuclear Information System (INIS)

    Peker, L.K.; Rasmussen, J.O.; Hamilton, J.H.

    1982-01-01

    Coriolis Coupling V/sub cor/ plays an important role in deformed nuclei. V/sub cor/ is proportional to h 2 /J[j (j + 1) -Ω (Ω + 1)]/sup 1/2/ and therefore is particularly significant in the nuclei with large j and low Ω Nilsson levels close to Fermi surface: n(i/sub 13/2/) in A = 150 to 170 rare-earth nuclei and p(i/sub 13/2/) and n(j/sub 15/2/) in A greater than or equal to 224 actinide nuclei. Because of larger j (n(j/sub 15/2/) versus n(i/sub 13/2/)) and smaller deformations (β approx. = 0.22 versus β 0.28) it was reasonable to expect that in actinide nuclei Coriolis effects are stronger than in the rare earth nuclei. Recently it was realized that the strength of observed Coriolis effects depends not only on the genuine Coriolis Coupling but also on the interplay between Coriolis ad pairing forces which leads to an interference between the wave functions of two mixing rotational bands. As a consequence the effective interaction V/sub eff/ of both bands is an oscillating function of the degree of shell filling (or chemical potential lambda F). It was shown that in the rare earth nuclei this interference strongly influenced conclusions about the trends in the Coriolis coupling strength and explained many of the observed band-mixing features (the sharpness of back banding curves, details of the blocking effect etc.). From theoretical analysis it was concluded that in the majority of actinide nuclei the effective interaction V/sub eff/ is strong, and therefore the Coriolis band-mixing have to be very strong. In this paper we would like to demonstrate that contrary to these predictions experimental data suggest that Coriolis band mixing in studied actinide nuclei is relatively weak and possibly significantly weaker than in rare earth nuclei

  9. Rare-earth magnets and their applications. Vol. 2. Proceedings

    International Nuclear Information System (INIS)

    Schultz, L.; Mueller, K.H.

    1998-01-01

    The following topics were dealt with: permanent magnets, rare- earth magnets, manufacturing, markets, powder metallurgy, sintering, mechanical alloying, nanocrystalline magnets, Curie temperature, domain structure, exchange coupling, stoichiometry effects, coercive force, remanence, magnetisation distribution, demagnetisation, mechanical properties, deformation behaviour, microstructure, grain size effects, texture, magnetic anisotropy, hydrogen assisted processing, nitriding, hydrogen embrittlement, permanent magnet motors, permanent magnet generators, brushless machines, linear motors, DC motors, AC motors, servomotors, magnetic levitation, magnetic field calculations, magnetic damping, magnet system design, system optimisation, corrosion protection, magnetometers, hard magnetic films, magnetostriction, magnetic multilayers, spin glass behaviour

  10. Thermoluminescence dosimetry of rare earth doped calcium ...

    Indian Academy of Sciences (India)

    Unknown

    CaAl2O4) doped with different rare earth ions have been studied and their suitability for radiation dosimetry applications is discussed. It is observed that monocalcium aluminate doped with cerium is a good dosimeter having linear response up to ...

  11. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    2015-11-27

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 6. Ultrasonic attenuation in rare-earth monoarsenides .... Proceedings of the International Workshop/Conference on Computational Condensed Matter Physics and Materials Science (IWCCMP-2015). Posted on November 27, 2015. Guest Editors: Anurag ...

  12. Rare earth oxyhalogenide base thermoluminescent material

    International Nuclear Information System (INIS)

    Rabatin, J.G.

    1976-01-01

    A process is described that consists to expose a thermoluminescent material to ionizing radiations, the material being a rare earth oxyhalogenide with terbium additions, to heat this material up to the emission of visible radiations and to measure the emitted radiations which are proportional to the ionizing radiation dose [fr

  13. Cerium and rare earth separation process

    International Nuclear Information System (INIS)

    Martin, M.; Rollat, M.

    1986-01-01

    An aqueous solution containing cerium III and rare earths is oxidized in the anodic compartment of an electrolytic cell, cerium IV is extracted by an organic solvent, the organic phase containing Ce IV is reduced in the catodic compartment of the same electrolytic cell and cerium III is extracted in a nitric aqueous phase [fr

  14. Lifetime measurements of the rare earths

    International Nuclear Information System (INIS)

    Stahnke, H.J.

    1981-01-01

    The lifetime of excited energy levels of Praseodymium, Neodymium, Gadolinium, Holmium and Erbium are measured. The measurements were done on atomic beams excited by laser radiation. The experimental results allow an interpretation of the electronic structure of the rare earths. (BEF)

  15. Rare earth phosphors and phosphor screens

    International Nuclear Information System (INIS)

    Buchanan, R.A.; Maple, T.G.; Sklensky, A.F.

    1981-01-01

    Advances in the use of stabilized rare earth phosphors and of conversion screens using these materials are examined. In particular the new phosphors discussed in this invention consist of oxybromides of yttrium, lanthanum and gadolinium with a luminescent activator ion stabilized by an oxychloride or oxyfluoride surface layer and the conversion screens include trivalent cerium as the activator ion. (U.K.)

  16. Non-rare earth magnetic nanoparticles

    Science.gov (United States)

    Carpenter, Everett E.; Huba, Zachary J.; Carroll, Kyler J.; Farghaly, Ahmed; Khanna, Shiv N.; Qian, Meichun; Bertino, Massimo

    2017-09-26

    Continuous flow synthetic methods are used to make single phase magnetic metal alloy nanoparticles that do not contain rare earth metals. Soft and hard magnets made from the magnetic nanoparticles are used for a variety of purposes, e.g. in electric motors, communication devices, etc.

  17. Alpha Anisotropy Studies of Near-Spherical and Deformed Nuclei

    CERN Multimedia

    Van Duppen, P

    2002-01-01

    % IS329 \\\\ \\\\ Although it was the first decay mode to be discovered, the process of $\\alpha$-particle emission is still poorly understood. A few years ago the first systematic study of anisotropic $\\alpha$-decay triggered renewed theoretical interest. Nevertheless, today the theories are still not adequate enough and more experimental data are urgently needed. We therefore measure the $\\alpha$-anisotropies of the favoured transitions of a number of near-spherical Rn and At isotopes, and of deformed nuclei near A=220. As the different models yield contradictory predictions for the transitions that are investigated, the measurements will allow to discern on their validity. They will at the same time provide the necessary basis for further theoretical developments.

  18. Tunneling from super- to normal-deformed minima in nuclei

    International Nuclear Information System (INIS)

    Khoo, T. L.

    1998-01-01

    An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The γ spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in ΔI = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters

  19. Tunneling from super- to normal-deformed minima in nuclei.

    Energy Technology Data Exchange (ETDEWEB)

    Khoo, T. L.

    1998-01-08

    An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The {gamma} spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in {Delta}I = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters.

  20. 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

  1. Fragmentation of single-particle states in deformed nuclei

    International Nuclear Information System (INIS)

    Malov, L.A.; Soloviev, V.G.

    1975-01-01

    Fragmentation of single-particle states on levels of deformed nuclei is studied on the example of 239 U and 169 Er nuclei in the framework of the model taking into consideration the interaction of quasiparticles with phonons. The dependence of fragmentation on the Fermi surface is considered from the viewpoint of single-particle levels. It is shown that in the distribution of single-particle strength functions a second maximum appears together with the large asymmetry maximum at high-energy excitation, and the distribution has a long ''tail''. A semimicroscopic approach is proposed for calculating the neutron strength functions. The following values of the strength functions are obtained: for sub(239)U-Ssub(0)sup(cal)=1.2x10sup(-4), Ssub(1)sup(cal)=2.7x10sub(-4) and for sub(169)Er-Ssub(0)sup(cal)=1.10sup(-4), Ssub(1)sup(cal)=1.2x10sup(-4)

  2. The industry of metallic rare earths (R.E.)

    International Nuclear Information System (INIS)

    Poirier, P.

    1979-01-01

    The following subjects are discussed: rare earths resources (rare earths abondance and world reserves, main ores). Rare earths separation and purification (ionic exchange, solvent extraction). Metallic rare earths and their mixtures, metallothermic reduction of oxides or fluorides (Ca, Mg, Al, Si or rare earth metals), Co-reduction process for intermetallic compounds (SmCo 5 ). Industrial applications of metallic rare earths (traditional applications such as flints, nodular cast iron, steel refining, magnesium industrie, applications under development such as rare earths/cobalt magnets, LaNi 5 for hydrogen storage, special alloys (automotive post combustion), magnetostrictive alloys). Economical problems: rare earth are elements relatively abundant and often at easily accessible prices. However, this group of 15 elements are liable to certain economical restraints. It is difficult to crack ore for only one rare earth. Availability of one given rare earth must be associated with the other corresponding rare earths to absorb all the other rare earths in other applications. Rare-earth industry has a strong expanding rate. 20% per year average for 6 years with Rhone-Poulenc. Thanks to their exceptional, specific characteristics rare earths have a bright future particularly for their metals

  3. Nuclear quadrupole-quadrupole interaction in the inelastic scattering of aligned deuterons from deformed nuclei

    International Nuclear Information System (INIS)

    Clement, H.; Frick, R.; Graw, G.; Schiemenz, P.; Seichert, N.

    1983-01-01

    The 2 1 + -excitation of deformed nuclei by tensor polarized deuterons provides an alignment of both nuclei and thus a means to study specifically the quadrupole-quadrupole interaction between both nuclei. The tensor analyzing power Asub(xz)(theta) has been measured for the elastic and inelastic scattering on 24 Mg and 28 Si. The coupled channel analysis including a deformed tensor potential reveals a clear signature of the quadrupole-quadrupole part of the nuclear projectile-target interaction. (orig.)

  4. Rare earth oxide doping in oxide cathodes

    International Nuclear Information System (INIS)

    Engelsen, Daniel den; Gaertner, Georg

    2006-01-01

    The effect on life performance and poisoning with O 2 by doping oxide cathodes with rare earth oxides and pseudo rare earth oxides, notably yttria, is qualitatively explained in terms of electrolysis of BaO during emission of electrons. Doped cathodes show less electrolysis and consume therefore less Ba during life: consequently, doped cathodes have a better life performance. However, the lower Ba-production makes doped cathodes more sensitive to oxygen poisoning. The experimentally found relation between conductivity and yttria concentration was the motive to propose a new model for the crystal imperfections in BaO. In this new imperfection model most Y 3+ -ions will combine with barium vacancies, therefore, the increase of the conductivity is modest and also the effect on the position of the Fermi level is modest. By assuming a combination of bulk and surface conductivity, the agreement between experiment and theory can be improved further

  5. Quantum Theory of Rare-Earth Magnets

    Science.gov (United States)

    Miyake, Takashi; Akai, Hisazumi

    2018-04-01

    Strong permanent magnets mainly consist of rare earths (R) and transition metals (T). The main phase of the neodymium magnet, which is the strongest magnet, is Nd2Fe14B. Sm2Fe17N3 is another magnet compound having excellent magnetic properties comparable to those of Nd2Fe14B. Their large saturation magnetization, strong magnetocrystalline anisotropy, and high Curie temperature originate from the interaction between the T-3d electrons and R-4f electrons. This article discusses the magnetism of rare-earth magnet compounds. The basic theory and first-principles calculation approaches for quantitative description of the magnetic properties are presented, together with applications to typical compounds such as Nd2Fe14B, Sm2Fe17N3, and the recently synthesized NdFe12N.

  6. Fascinating world of rare earth research

    International Nuclear Information System (INIS)

    Gschneidner, K.A. Jr.

    1977-01-01

    The first part of this paper concerns some of the notable events which occurred early in the author's career as a rare earther and some of the major events which took place in the two decades 1950 to 1970. The notable changes and advances in the rare earth research world since the 1971 Durham Conference are described in the second and largest part of the paper. The final portion is concerned with actinide developments since 1971

  7. Diagnostic study about lanthanides (rare earths)

    International Nuclear Information System (INIS)

    Ribeiro, G.F.

    1985-01-01

    The world situation of rare earths (lanthanides) is evaluated, and a comparison of the Brazilian situation in respect to other countries is established, concerning the following aspects: geology of mineral deposits; main sources, uses, reserves and production; their consumption, prices and state-of-art of geological researches and industrial processes for physical and chemical separation / concentration of these elements. (C.L.B.) [pt

  8. Mineralogy of the rare earth elements

    International Nuclear Information System (INIS)

    Clark, A.M.

    1984-01-01

    This paper contains mineralogic properties of the rare earth elements (REE). Notes are given on total REE abundances, distribution patterns, and modes of occurrence. References are confined as far as possible to papers containing usable REE data. The minerals are grouped alphabetically within each major cationic group. The paper includes an alphabetic table of mineral names, chemical formulas, crystal system and section number. It functions as a handy entrance to the mineralogic and bibliographic paper. (G.J.P.)

  9. Structure of small rare earth clusters

    International Nuclear Information System (INIS)

    Rayane, D.; Benamar, A.; Tribollet, B.; Broyer, M.; Melinon, P.

    1991-01-01

    Rare earth clusters are produced by the inert gas condensation technique. The observed size distribution shows large peaks at n=13, 19, 23, 26, 29, 32, 34, 37, 39, 45, .... The beginning of this sequence (up to 34) has been already observed in argon clusters and recently by our group in barium clusters; this sequence may be interpreted in terms of icosahedral structures corresponding to the addition of caps on a core icosahedron of 13 atoms. (orig.)

  10. Atomic masses of rare-earth isotopes

    International Nuclear Information System (INIS)

    Schmidt-Ott, W.D.; Kantus, R.; Runte, E.

    1981-01-01

    A survey is given of decay energies of rare-earth isotopes measured in electron-capture decay by relative Psub(K) ratios, ECsub(K)/β + , and EC/β + ratios. Atomic masses of A = 147 isotopes and of 146 Gd and 148 Dy were derived. The masses of these isotopes and of α-decaying precessors are compared with predictions of current mass formulae. The subshell closure at Z = 64 is shown for N = 82, and 84 isotones. (orig.)

  11. Epitaxial rare-earth superlattices and films

    International Nuclear Information System (INIS)

    Salamon, M.B.; Beach, R.S.; Flynn, C.P.; Matheny, A.; Tsui, F.; Rhyne, J.J.

    1992-01-01

    This paper reports on epitaxial growth of rare-earth superlattices which is demonstrated to have opened important new areas of research on magnetic materials. The propagation magnetic order through non-magnetic elements, including its range and anisotropy, has been studied. The importance of magnetostriction in determining the phase diagram is demonstrated by the changes induced by epitaxial clamping. The cyrstallinity of epitaxial superlattices provides the opportunity to study interfacial magnetism by conventional x-ray and neutron scattering methods

  12. Anthropogenic Cycles of Rare Earth Elements

    Science.gov (United States)

    Du, X.; Graedel, T. E.

    2009-12-01

    This research will develop quantitatively resolved anthropogenic cycles and in-use stocks for the rare earth metals specifically cerium, lanthanum and dysprosium in Japan, China, and the U.S. for the year of 2007. Rare earth elements (REE) is a group of 17 scare metals widely used in a growing number of emerging technologies and have been in high demand for emerging technologies as raw materials during past the three decades. New market participants from newly industrializing countries, primarily China, have had strong impacts on the demand of share. Consequently, the importance to sustain a reliable, steady, uninterrupted supply on global market triggered comprehensive research to recognize and understand the life cycles of rare earths. Moreover, because China plays a dominant role in mining production since 1990, it requires the assessment for the countries, which are almost completely dependent on imports from China with respect to rare earth resources. The study aims to analyze the flows and stocks of rare earth elements individually as elemental form in spite of their natural geological co-occurrence and mixed composition in applications. By applying the method of Material Flow Analysis (MFA) work has been done on evaluating current and historical flows of specific technologically significant materials, for example, copper, zinc, nickel, etc., determining the stocks available in different types of reservoirs (e.g., lithosphere, in-use) and the flows among the reservoirs, developing scenarios of possible futures of metal use, and assessing the environmental and policy implications of the results. Therefore, REE as a new target deserves inclusion because of its potential demand-supply conflict and importance to secure the competitive advantage of technical innovation in future. This work will generate a quantitatively resolved anthropogenic life cycle and in-use stocks for REE for the main target countries for a chosen year, 2007, providing flows and stocks from

  13. Relativistic extension of the complex scaled Green's function method for resonances in deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Min [Anhui University, School of Physics and Materials Science, Hefei (China); RIKEN Nishina Center, Wako (Japan); Shi, Xin-Xing; Guo, Jian-You [Anhui University, School of Physics and Materials Science, Hefei (China); Niu, Zhong-Ming [Anhui University, School of Physics and Materials Science, Hefei (China); Interdisciplinary Theoretical Science Research Group, RIKEN, Wako (Japan); Sun, Ting-Ting [Zhengzhou University, School of Physics and Engineering, Zhengzhou (China)

    2017-03-15

    We have extended the complex scaled Green's function method to the relativistic framework describing deformed nuclei with the theoretical formalism presented in detail. We have checked the applicability and validity of the present formalism for exploration of the resonances in deformed nuclei. Furthermore, we have studied the dependences of resonances on nuclear deformations and the shape of potential, which are helpful to recognize the evolution of resonant levels from stable nuclei to exotic nuclei with axially quadruple deformations. (orig.)

  14. Preparation of rare earth fluorides from apatite concentrate

    International Nuclear Information System (INIS)

    Mulyarchuk, I.F.; Voloshchenko, M.V.; Zen'kovich, E.G.; Sumenkova, V.V.; AN Ukrainskoj SSR, Kiev. Inst. Problem Lit'ya)

    1980-01-01

    The processes of preparation of the rare earths element sum from apatite concentrate of the Khibins, connected with preliminary extraction of rare earth phosphates from nitric acid extract using solvent extraction or direct precipitation from the extract by solution of potassium and ammonium fluorides. The sequence of the processes of the first variant is the following: solvent extraction of rare earths by tributylphosphate from clarified nitric acid extract of apatite with subsequent reextraction of rare earths with water and precipitation of rare earth phosphates from aqueous solution during neutralization by ammonia. In case of fluoride preparation from rare earth phosphate the main attention is paid to precipitation and filtration of fluorides. Technological scheme and cost price of industry for the production of 1800 t of rare earth trifluorides a year are calculated. When taking account of TBP losses according to its solubility the industry cost price is 1O times lower the modern cost of rare earth fluorides

  15. K isomerism and collectivity in neutron-rich rare-earth isotopes.

    OpenAIRE

    Patel, Zena

    2016-01-01

    Neutron-rich rare-earth isotopes were produced by in-flight fission of 238U ions at the Radioactive Isotope Beam Factory (RIBF), RIKEN, Japan. In-flight fission of a heavy, high-intensity beam of 238U ions on a light target provides the cleanest secondary beams of neutron-rich nuclei in the rare-earth region of isotopes. In-flight fission is advantageous over other methods of nuclear production, as it allows for a secondary beam to be extracted, from which the beam species can be separated an...

  16. Two-neutron transfer reactions with heavy-deformed nuclei

    International Nuclear Information System (INIS)

    Price, C.; Landowne, S.; Esbensen, H.

    1988-01-01

    In a recent communication we pointed out that one can combine the macroscopic model for two-particle transfer reactions on deformed nuclei with the sudden limit approximation for rotational excitation, and thereby obtain a practical method for calculating transfer reactions leading to high-spin states. As an example, we presented results for the reaction 162 Dy( 58 Ni, 60 Ni) 160 Dy populating the ground-state rotational band up to the spin I = 14 + state. We have also tested the validity of the sudden limit for the inelastic excitation of high spin states and we have noted how the macroscopic model may be modified to allow for more microscopic nuclear structure effects in an application to diabolic pair-transfer processes. This paper describes our subsequent work in which we investigated the systematic features of pair-transfer reactions within the macroscopic model by using heavier projectiles to generate higher spins and by decomposing the cross sections according to the multipolarity of the transfer interaction. Particular attention is paid to characteristic structures in the angular distributions for the lower spin states and how they depend on the angular momentum carried by the transferred particles. 11 refs., 3 figs

  17. Distribution of rare earths in liver of mice administered with chloride compounds of 12 rare earths

    International Nuclear Information System (INIS)

    Shinohara, A.; Chiba, M.; Inaba, Y.

    1998-01-01

    Full text: Rare earths are used in high technology field, however, the information on their biological effects are not sufficient. The behaviour of rare earths in biology is of interest in connection with their toxicity. In the present study, the distribution of rare earths in liver of mice administered with these elements was investigated. The effects on Ca and other biological essential elements were also determined. Male mice (5 weeks old) were injected with one of 12 kinds of rare earths (chlorides of Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb) at the dose of 25 mg/KXg body weight. After 20 hours of administration, mice were sacrificed, then liver and other organs were taken out. Liver was homogenized and separated by centrifugation. The concentrations of rare earths administered were measured by microwave-induced plasma-mass spectrometry (MIP-MS) after acid digestion. The concentrations of administered elements in whole liver were about 100μg/g (wet weight), where the difference between elements was few. Distribution amounts of elements administered in four fractions were following order; 700μg precipitate > mitocondrial fraction > microsomal fraction > cytosol. The relative contents in these fractions, however, was different depending on the element administered. Calcium concentrations in liver of administered mice were higher than those of control mice. Increase of Ca concentrations were observed in all four fractions and the increase ratio was also dependent on the elements administered

  18. Description of the hexadecapole deformation parameter in the sdg interacting boson model

    International Nuclear Information System (INIS)

    Liu Yuxin; Sun Di; Wang Jiajun; Han Qizhi

    1998-01-01

    The hexadecapole deformation parameter β 4 of the rare-earth and actinide nuclei is investigated in the framework of the sdg interacting boson model. An explicit relation between the geometric hexadecapole deformation parameter β 4 and the intrinsic deformation parameters ε 4 , ε 2 are obtained. The deformation parameters β 4 of the rare-earths and actinides are determined without any free parameter. The calculated results agree with experimental data well. It also shows that the SU(5) limit of the sdg interacting boson model can describe the β 4 systematics as well as the SU(3) limit

  19. Description of the Hexadecapole Deformation Parameter in the sdg Interacting Boson Model

    Science.gov (United States)

    Liu, Yu-xin; Sun, Di; Wang, Jia-jun; Han, Qi-zhi

    1998-04-01

    The hexadecapole deformation parameter β4 of the rare-earth and actinide nuclei is investigated in the framework of the sdg interacing boson model. An explicit relation between the geometric hexadecapole deformation parameter β4 and the intrinsic deformation parameters epsilon4, epsilon2 are obtained. The deformation parameters β4 of the rare-earths and actinides are determined without any free parameter. The calculated results agree with experimental data well. It also shows that the SU(5) limit of the sdg interacting boson model can describe the β4 systematics as well as the SU(3) limit.

  20. Rare earth elements behavior in Peruibe black mud

    Energy Technology Data Exchange (ETDEWEB)

    Torrecilha, Jefferson K.; Carvalho, Leandro P.; Gouvea, Paulo F.M.; Silva, Paulo S.C. da, E-mail: jeffkoy@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Rare earth elements in sediments have been used as powerful tools for environmental studies because of their behavior during geochemical processes and are also widely accepted as reliable provenance tracers because they are largely water-immobile and thus behave conservatively during sedimentary processes. The Peruibe Black Mud (PBM) is a sedimentary deposit originated from the interactions of marine sediments and organic matter in an estuarine environment that originates a peloid currently used for medicinal purposes. The objective of this study was to examine rare earth elements pattern distribution in the Peruibe black mud sedimentary deposit as a proxy for its geochemical development. Elemental ratios such as LaN/YbN, Th/U and La/Th were determined and a normalization of the mean rare earth elements concentrations in the samples related to NASC indicates that the light (La to Eu) rare earth elements present values close to the unity while the heavy (Tb to Lu) rare earth elements are depleted related to NASC. It can be observed that the light rare earth elements present enrichment values slightly enriched over the unity while the heavy rare earth elements present values generally below the unity reflecting the enrichment of the light rare earth elements over the heavy rare earth. Rare earth elements concentrations determined in Peruibe black mud samples showed a distribution similar to that found in the NASC for the light rare earth elements and depleted for the heavy rare earth elements. (author)

  1. Rare earth elements behavior in Peruibe black mud

    International Nuclear Information System (INIS)

    Torrecilha, Jefferson K.; Carvalho, Leandro P.; Gouvea, Paulo F.M.; Silva, Paulo S.C. da

    2015-01-01

    Rare earth elements in sediments have been used as powerful tools for environmental studies because of their behavior during geochemical processes and are also widely accepted as reliable provenance tracers because they are largely water-immobile and thus behave conservatively during sedimentary processes. The Peruibe Black Mud (PBM) is a sedimentary deposit originated from the interactions of marine sediments and organic matter in an estuarine environment that originates a peloid currently used for medicinal purposes. The objective of this study was to examine rare earth elements pattern distribution in the Peruibe black mud sedimentary deposit as a proxy for its geochemical development. Elemental ratios such as LaN/YbN, Th/U and La/Th were determined and a normalization of the mean rare earth elements concentrations in the samples related to NASC indicates that the light (La to Eu) rare earth elements present values close to the unity while the heavy (Tb to Lu) rare earth elements are depleted related to NASC. It can be observed that the light rare earth elements present enrichment values slightly enriched over the unity while the heavy rare earth elements present values generally below the unity reflecting the enrichment of the light rare earth elements over the heavy rare earth. Rare earth elements concentrations determined in Peruibe black mud samples showed a distribution similar to that found in the NASC for the light rare earth elements and depleted for the heavy rare earth elements. (author)

  2. Rare earth elements materials production from apatite ores

    International Nuclear Information System (INIS)

    Anufrieva, A V; Buynovskiy, A S; Makaseev, Y N; Mazov, I N; Nefedov, R A; Sachkov, V I; Valkov, A V; Andrienko, O S; Stepanova, O B

    2016-01-01

    The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics. (paper)

  3. Rare earth permanent magnet with easy magnetization

    International Nuclear Information System (INIS)

    Kim, A.S.; Camp, F.E.

    1998-01-01

    Rare earth permanent magnets have high energy products and coercivities, and thus the volume miniaturization of magnetic devices has been possible with improved magnetic performance. Although the high energy products of these rare earth permanent magnets provide substantial advantages for magnetic design and application, the strong magnetic force of the magnetized magnets makes assembly difficult. Therefore, a special device is needed to assemble the magnetized magnets. On the other hand, unmagnetized magnets are assembled and then they are magnetized. The assembled magnets are generally more difficult to magnetize than unassembled magnets because a much less effective magnetic field may be applied to them. This is particularly true for the rare earth permanent magnets because they usually need a much higher magnetic field to be fully magnetized than alnico or ferrite magnets. To obtain optimum magnetic properties, the required minimum magnetizing fields for SmCo 5 , Sm 2 TM 17 and Nd 2 Fe 14 B magnets were reported as 25-30 kOe, 45-60 kOe and 25-30 kOe, respectively. If the required magnetizing field for full saturation could be lowered, the effective utilization of magnetic properties would be maximized and the magnetic design option could be expanded with reduced restrictions. To meet this demand, we have sought to lower the field required for full magnetic saturation, and found that an increase in Dy content in R-(Fe,Co,Cu)-B type magnets lowers the field required for full saturation as well as improves the temperature stability. By increasing the H ci with Dy addition from 14 kOe to 24 and 34 kOe, the field required for full magnetic saturation decreases from about 20 to 15 and 10 kOe, respectively. This dual benefit will open up new application areas with more freedom for magnet design options. The mechanism for the lower magnetizing fields will be discussed. (orig.)

  4. Port Pirie rare earths plant stage 3

    International Nuclear Information System (INIS)

    1990-08-01

    SX Holdings Limited intends to establish a rare earths plant at Port Pirie, South Australia. The proposal involves three stages of development, Stage 3 being to develop a monazite cracking plant and associated rare earths separation facility with the capacity to process up to 8,000 t/a of monazite-type ores. The proposed initial capacity is 4,000 t/a. This Draft Environmental Impact Statement relates to Stage 3 and is based on a monazite processing capacity of 8,000 t/a. The justification of the project is given in terms of use and the market for rare earths, the economic and environmental benefits of the proposal, the site selection process, site rehabilitation, and the consequences of not proceeding. A detailed description of the project is given, including the treatment process, site development and facilities, the supply of raw materials, product and waste handling, transport and storage, plant commissioning, operation and decommissioning, construction and staffing. The environmental issues entailed in the proposed development are discussed and include social effects, land use and infrasturcture considerations, risk management and transport. Occupational and environmental radiation issues, including assessments of exposure pathways and doses, management and monitoring, disposal of monosite residue are also discussed. It is estimated that the effects of disposal of 2,330 t/year of radioactive slurry in the sub-aerial tailing disposal system at Olympic Dam will be negligible. Moreover, the gamma dose increases would not result in any significant increase in occupational exposures. 38 refs., tabs., ills

  5. Enhanced separation of rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Herbst, R. S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Soderstrom, M. D. [Cytec Solvay Group, Tempe, AZ (United States); Jakovljevic, B. [Cytec Solvay Group, Niagara Falls, ON (Canada)

    2016-09-01

    Industrial rare earth separation processes utilize PC88A, a phosphonic acid ligand, for solvent extraction separations. The separation factors of the individual rare earths, the equipment requirements, and chemical usage for these flowsheets are well characterized. Alternative ligands such as Cyanex® 572 and the associated flowsheets are being investigated at the pilot scale level to determine if significant improvements to the current separation processes can be realized. These improvements are identified as higher separation factors, reduced stage requirements, or reduced chemical consumption. Any of these improvements can significantly affect the costs associated with these challenging separation proccesses. A mid/heavy rare earth element (REE) separations flowsheet was developed and tested for each ligand in a 30 stage mixer-settler circuit to compare the separation performance of PC88A and Cyanex® 572. The ligand-metal complex strength of Cyanex® 572 provides efficient extraction of REE while significantly reducing the strip acid requirements. Reductions in chemical consumption have a significant impact on process economics for REE separations. Partitioning results summarized Table 1 indicate that Cyanex® 572 offers the same separation performance as PC88A while reducing acid consumption by 30% in the strip section for the mid/heavy REE separation. Flowsheet Effluent Compositions PC88A Cyanex® 572 Raffinate Mid REE Heavy REE 99.40% 0.60% 99.40% 0.60% Rich Mid REE Heavy REE 2.20% 97.80% 0.80% 99.20% Liquor Strip Acid Required 3.4 M 2.3 M Table 1 – Flowsheet results comparing separation performance of PC88A and Cyanex® 572 for a mid/heavy REE separation.

  6. Luminescence studies of rare earth doped dosimeters

    International Nuclear Information System (INIS)

    Karali, T.

    1999-10-01

    The main objective of this thesis has been to address the applications and fundamentals of thermoluminescence (TL) and to contribute to existing knowledge about TL mechanisms in materials which are applied as radiation dosimeters. This issue has been explored for a long time but the mechanisms lack completeness and certainty. TL, Radioluminescence (RL) and Radio-thermoluminescence (RLTL) measurements have been conducted on a high sensitivity TL spectrometer both at low (30-290 K) and high (25-400 deg. C) temperatures, and different heat treatments (furnace and laser) were conducted in order to study the possible impurity clustering which changes the TL spectra and efficiency of the dosimeters. Studies have been based on three different host structure, namely sulphate, borates and zircon. The spectra of calcium sulphate samples doped with Tm 3+ and Dy 3+ at different concentration were examined using TL, RL and RLTL. Similar procedures were applied to the borate samples. Modifications of the material by thermal treatments convert the state of dispersion of the rare earth ions between isolated, pair or defect clusters, which alter the dosimeter efficiency. In some cases, modified geometries are detectable by movement of the line emissions such as for quenched samples which are attributable to new microcrystal line phases. The study of co-doped samples showed unequivocal evidence of a glow peak displacement of the two dopants within a single sample. This result supports the new view that RE 3+ ions could form part of a complex defect acting as both charge trap and recombination centres. Pulsed laser heating with a UV laser changed the glow curve shape and lead to strong signals. The detailed mechanisms for this process are discussed. The RL and TL spectra of synthetic zircon crystals doped with different RE 3+ ions (Pr, Sm, Eu, Gd, Ho, Dy, Er, and Yb) and phosphorus are reported. Even though there is some intrinsic emission from the host lattice the major signals are

  7. Alternative value chains for rare earths

    DEFF Research Database (Denmark)

    Machacek, Erika; Fold, Niels

    2014-01-01

    The 2011 peak in rare earth element (REE) prices revealed a vast knowledge gap on the REE-based industry considered to be almost monopolized by Chinese players. A global value chain (GVC) framework is used to provide an understanding of value-adding segments of REE in their transformation from mine...... to market but inquiries on the currently most-advanced company strategies for alternative REE supplies form the cornerstone of this paper. The Anglo-REE deposit developer strategies are aligned with the value-adding segments and different approaches to integration and co-optation of REE processing...

  8. nuclei

    Directory of Open Access Journals (Sweden)

    Minkov N.

    2016-01-01

    Full Text Available We study the effects of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even heavy and superheavy nuclei. The neutron two-quasiparticle (2qp isomeric energies and magnetic dipole moments are calculated within a deformed shell model with the Bardeen-Cooper- Schrieffer (BCS pairing interaction over a wide range of quadrupole and octupole deformations. We found that in most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation, while the 2qp energies indicate regions of nuclei in which the presence of high-K isomeric states may be associated with the presence of octupole softness or even with octupole deformation. In the present work we also examine the influence of the BCS pairing strength on the energy of the blocked isomer configuration. We show that the formation of 2qp energy minima in the space of quadrupole-octupole and eventually higher multipolarity deformations is a subtle effect depending on nuclear pairing correlations.

  9. THE LINK BETWEEN RARE-EARTH PEAK FORMATION AND THE ASTROPHYSICAL SITE OF THE R PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Mumpower, Matthew R. [Theory Division, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); McLaughlin, Gail C. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Surman, Rebecca [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Steiner, Andrew W., E-mail: matthew@mumpower.net [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)

    2016-12-20

    The primary astrophysical source of the rare-earth elements is the rapid neutron capture process ( r process). The rare-earth peak that is seen in the solar r -process residuals has been proposed to originate as a pile-up of nuclei during the end of the r process. We introduce a new method utilizing Monte Carlo studies of nuclear masses in the rare-earth region, that includes self-consistently adjusting β -decay rates and neutron capture rates, to find the mass surfaces necessary for the formation of the rare-earth peak. We demonstrate our method with two types of astrophysical scenario, one corresponding to conditions typical of hot winds from core-collapse supernovae and stellar-mass accretion disks, and one corresponding to conditions typical of the ejection of the material from the tidal tails of neutron star mergers. In each type of astrophysical condition, this method successfully locates a region of enhanced stability in the mass surface that is responsible for the rare-earth peak. For each scenario, we find that the change in the mass surface has qualitatively different features, thus future measurements can shed light on the type of environment in which the r process occurred.

  10. THE LINK BETWEEN RARE-EARTH PEAK FORMATION AND THE ASTROPHYSICAL SITE OF THE R PROCESS

    International Nuclear Information System (INIS)

    Mumpower, Matthew R.; McLaughlin, Gail C.; Surman, Rebecca; Steiner, Andrew W.

    2016-01-01

    The primary astrophysical source of the rare-earth elements is the rapid neutron capture process ( r process). The rare-earth peak that is seen in the solar r -process residuals has been proposed to originate as a pile-up of nuclei during the end of the r process. We introduce a new method utilizing Monte Carlo studies of nuclear masses in the rare-earth region, that includes self-consistently adjusting β -decay rates and neutron capture rates, to find the mass surfaces necessary for the formation of the rare-earth peak. We demonstrate our method with two types of astrophysical scenario, one corresponding to conditions typical of hot winds from core-collapse supernovae and stellar-mass accretion disks, and one corresponding to conditions typical of the ejection of the material from the tidal tails of neutron star mergers. In each type of astrophysical condition, this method successfully locates a region of enhanced stability in the mass surface that is responsible for the rare-earth peak. For each scenario, we find that the change in the mass surface has qualitatively different features, thus future measurements can shed light on the type of environment in which the r process occurred.

  11. Monazite upgradation and production of high pure rare earths

    International Nuclear Information System (INIS)

    Asnani, C.K.; Mohanty, D.; Kumar, S.S.

    2014-01-01

    Rare earth extraction from monazite and further processing of mixed rare earth chlorides for producing individual high pure rare earths involves a complex flowsheet based on solvent extraction process. Apart from involving multiple extractions, scrubbing and stripping operations, the flowsheet requires optimization of critical parameters such as solvent molarity, solvent saponification level and recycling of product solutions as reflux to ensure preferential upload of required rare earths to generate high purity product. This paper tracks monazite flow from the raw sand feed through to the monazite product and its processing to generate rare earths of internationally acceptable quality

  12. Thermoelectric transport in rare-earth compounds

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Ulrike

    2007-07-01

    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce{sub 3}Rh{sub 4}Sn{sub 13} are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu{sub 1-x}Yb{sub x}Rh{sub 2}Si{sub 2} and Ce{sub x}La{sub 1-x}Ni{sub 2}Ge{sub 2} by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  13. Magnetoelastic interaction in rare earth systems

    International Nuclear Information System (INIS)

    Dohm, V.

    1975-01-01

    A theory of rotationally invariant spin-lattice interactions in rare earth systems is presented. It is shown that rotational invariance to leading order is ensured only if rotational interactions of first and second order in the displacements are included simultaneously in the spin-lattice Hamiltonian. The rotational second-order interactions yield effects which are as large as those of the linear rotational interaction. It is pointed out that a corresponding statement should hold also for pure strain interactions. The phonon Green's function is calculated for the paramagnetic phase of rare earth systems. It is found that in an applied magnetic field the rotational interactions cause measureable changes of the phonon dispersion and the sound velocity even for cubic symmetry. These effects turn out to be of the same order of magnitude as the conventional field-dependent strain effects and are qualitatively different from the latter. The results of our theory are illustrated by the example of SmSb, and quantitative predictions for the transverse sound velocities are given. (orig.) [de

  14. Costs and benefits of rare earth screens

    International Nuclear Information System (INIS)

    Taylor, F.E.

    1977-01-01

    The British Institute of Radiology has submitted evidence (Royal Commission on Environmental Pollution, 1976, Sixth Report, Nuclear Power and the Environment. Cmnd 6618, HMSO, London) leading to the conclusion that the introduction of rare earth screens in medical radiography is not financially practical at present in the U.K. This conclusion is questioned. The cost of reducing the genetic dose from medical radiography should be compared with the costs of reducing that from other sources such as nuclear power wastes, since the risks are to future generations in both cases. The cost of reducing public exposure by the use of rare earth screens in U.K. hospitals is calculated to be about Pound1 per man-rad; a total annual genetic collective dose of nearly 300,000 man-rad could be saved. An anomalous situation is presented by the great discrepancies between this cost, and published estimates both of the cost of the detriment associated with the genetic collective dose and of the value incorporated into the design objective for nuclear reactors. (U.K.)

  15. Thermoelectric transport in rare-earth compounds

    International Nuclear Information System (INIS)

    Koehler, Ulrike

    2007-01-01

    This work focuses on the thermoelectric transport in rare-earth compounds. The measurements of the thermal conductivity, thermopower, and Nernst coefficient are supplemented by investigations of other quantities as magnetic susceptibility and specific heat. Chapter 2 provides an introduction to the relevant physical concepts. Section 1 of that chapter summarizes the characteristic properties of rare-earth systems; section 2 gives an overview on thermoelectric transport processes in magnetic fields. The applied experimental techniques as well as the new experimental setup are described in detail in Chapter 3. The experimental results are presented in Chapter 4-6, of which each concentrates on a different subject. In Chapter 4, various Eu clathrates and the skutterudite-like Ce 3 Rh 4 Sn 13 are presented, which have been investigated as potential thermoelectric materials for applications. Chapter 5 focusses on the study of the energy scales in the heavy-fermion series Lu 1-x Yb x Rh 2 Si 2 and Ce x La 1-x Ni 2 Ge 2 by means of thermopower investigations. Chapter 6 is dedicated to the thermoelectric transport properties of the correlated semimetal CeNiSn with special emphasis on the Nernst coefficient of this compound. (orig.)

  16. The lattice dynamical studies of rare earth compounds: electron-phonon interactions

    International Nuclear Information System (INIS)

    Jha, Prafulla K.; Sanyal, Sankar P.; Singh, R.K.

    2002-01-01

    During the last two decades chalcogenides and pnictides of rare earth (RE) atoms have drawn considerable attention of the solid state physicists because of their peculiar electronic, magnetic, optical and phonon properties. Some of these compounds e.g. sulphides and selenides of cerium (Ce), samarium (Sm), yttrium (Y), ytterbium (Yb), europium (Eu) and thulium (Tm) and their alloys show nonintegral valence (between 2 and 3), arising due to f-d electron hybridization at ambient temperature and pressure. The rare earth mixed valence compounds (MVC) reviewed in this article crystallize in simple cubic structure. Most of these compounds show the existence of strong electron-phonon coupling at half way to the zone boundary. This fact manifests itself through softening of the longitudinal acoustic mode, negative value of elastic constant C 12 etc. The purpose of this contribution is to review some of the recent activities in the fields of lattice dynamics and allied properties of rare earth compounds. The present article is primarily devoted to review the effect of electron-phonon interactions on the dynamical properties of rare earth compounds by using the lattice dynamical model theories based on charged density deformations and long-range many body forces. While the long range charge transfer effect arises due to f-d hybridization of nearly degenerate 4f-5d bands of rare earth ions, the density deformation comes into the picture of breathing motion of electron shells. These effects of charge transfer and charge density deformation when considered in the lattice dynamical models namely the three body force rigid ion model (TRM) and breathing shell model (BSM) are quite successful in explaining the phonon anomalies in these compounds and undoubtedly unraveled many important physical process governing the phonon anomalies in rare earth compounds

  17. Emerging industrial processes for low grade rare earth mineral concentrates

    International Nuclear Information System (INIS)

    Soldenhoff, Karin; Ho, Elizabeth

    2015-01-01

    Historically rare earth recovery has mainly been derived from the processing of monazite, bastnasite and xenotime containing ores amenable to beneficiation, yielding high grade mineral concentrates. A notable exception is the recovery of heavy rare earths from ionic clays in Southern China. Recently, projects are being proposed to treat a range of mineral concentrates which tend to be lower grade with wide ranging modal mineralogy for rare earths and associated gangue minerals. This has a significant impact on processing routes. This paper discusses processes proposed for emerging rare earth producers and how different projects have responded to particular challenges including: Control of phosphorous due to the presence of xenotime or monazite type minerals; Control of phosphorous due to the presence of rare earth containing apatite; Rare earth recovery from polymetallic ores; Control of radionuclides in rare earth processing, etc.

  18. Polarized electric dipole moment of well-deformed reflection asymmetric nuclei

    International Nuclear Information System (INIS)

    Denisov, V.Yu.

    2012-01-01

    The expression for polarized electric dipole moment of well-deformed reflection asymmetric nuclei is obtained in the framework of liquid-drop model in the case of geometrically similar proton and neutron surfaces. The expression for polarized electric dipole moment consists of the first and second orders terms. It is shown that the second-order correction terms of the polarized electric dipole moment are important for well-deformed nuclei

  19. New estimates of quadrupole deformation β of some nearly spherical even Mo nuclei

    International Nuclear Information System (INIS)

    Singh, Y.; Gupta, K.K.; Singh, M.; Bihari, Chhail; Varshney, A.K.; Gupta, D.K.

    2013-01-01

    The deformation parameter β and γ of the collective model of Bohr and Mottelson are basic descriptors of the nuclear equilibrium shape and structure. In recent past the sets of deformation parameters (β, γ) have been extracted from both level energies and E2 transition rates in even Xe, Ba and Ce nuclei and Hf, W, Os, Pt and Hg nuclei using rigid triaxial rotor model of Davydov – Filippov

  20. {Delta}I = 2 energy staggering in normal deformed dysprosium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.A.; Brown, T.B.; Archer, D.E. [Florida State Univ., Tallahassee, FL (United States)] [and others

    1996-12-31

    Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.

  1. Spectroscopy high above the yrast line in rare earth nuclei

    International Nuclear Information System (INIS)

    Ramsoey, T.

    1990-01-01

    The particle-gamma coincidence technique presented in this work has proved to be a powerful tool in the study of nuclear structure. The most important feature is the ability to select well-defined excitation regions of entry states in a narrow spin window. The author has focused on the gamma-decay of low- lying descrete states and the gross structure properties in the region far above the yrast line. 6 refs., 5 figs

  2. Excited bands in even-even rare-earth nuclei

    International Nuclear Information System (INIS)

    Vargas, Carlos E.; Hirsch, Jorge G.

    2004-01-01

    The energetics of states belonging to normal parity bands in even-even dysprosium isotopes, and their B(E2) transition strengths, are studied using an extended pseudo-SU(3) shell model. States with pseudospin 1 are added to the standard pseudospin 0 space, allowing for a proper description of known excited normal parity bands

  3. Level density and thermal properties in rare earth nuclei

    International Nuclear Information System (INIS)

    Schiller, A.; Guttormsen, M.; Hjorth-Jensen, M.; Melby, E.; Rekstad, J.; Siem, S.

    2001-01-01

    A convergent method to extract the nuclear level density and the γ-ray strength function from primary γ-ray spectra has been established. Thermodynamical quantities have been obtained within the microcanonical and canonical ensemble theory. Structures in the caloric curve and in the heat capacity curve are interpreted as fingerprints of breaking of Cooper pairs and quenching of pairing correlations. The strength function can be described using models and common parametrizations for the E1, M1, and pygmy resonance strength. However, a significant decrease of the pygmy resonance strength at finite temperatures has been observed

  4. Rare earth element patterns in nigerian coals

    International Nuclear Information System (INIS)

    Ewa, I.O.B.; Elegba, S.B.

    1996-01-01

    Rare Earth Elements (REE's) retain group coherence in their environment and are therefore useful geochemical markers. We report the pattern of ten REE's (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Lu) determined by Instrumental Neutron Activation Analysis (INAA) for coals obtained from eight mines in Nigeria, namely, Okaba, Enugu, Ogbete, Onyeama, Gombe, Lafia, Asaba and Afikpo. Our results show the existence of fractionations with the highest index of 13.19 for Lafia coal, depletion in HREE, negative Eu anomaly for most of the coals, REE patterns that are consistent with chondritic trends; prominent (Eu/Eu * ) cn for Okaba and Gombe coals. Variations in geochemical data observed could suggest strong departures from band metamorphism during the coalification events of the Benue Trough geosynclines, where the coal deposits are all located. (author) 14 refs., 2 figs., 3 tabs

  5. Double selenates of rare earths and ammonium

    International Nuclear Information System (INIS)

    Iskhakova, L.D.; Kozlova, N.P.; Makarevich, L.G.

    1991-01-01

    Double selenates of rare earths with ammonium were prepared in result of crystallization. It is shown that NH 4 Ln(SeO 4 ) · nH 2 O crystalline hydrates are presented by penta-and trihydrates. Existance of two modifications was revealed for NH 4 Ln(SeO 4 ) · 5H 2 O: monoclinic form of NH 4 La(SeO 4 ) 2 · 5H 2 O, isostructural RbCe(SeO 4 ) 2 · 5H 2 O, and earlier unknown rhombic form of salts with Ln = Pr, Nd. Trihydrates with Ln = Sm-Yb belong to structural type of RbNd(SeO 4 ) 2 · 3H 2 O. Anhydrous salts NH 4 Ln(SeO 4 ) 2 are isostructural with monoclinic KNd(SO 4 ) 2 modification. Lattice parameters of binary selenates are presented

  6. Process for making rare earth metal chlorides

    International Nuclear Information System (INIS)

    Kruesi, P.R.

    1981-01-01

    An uncombined metal or a metal compound such as a sulfide, oxide, carbonate or sulfate is converted in a liquid salt bath to the corresponding metal chloride by reacting it with chlorine gas or a chlorine donor. The process applies to metals of groups 1b, 2a, 2b, 3a, 3b, 4a, 5a and 8 of the periodic table and to the rare earth metals. The chlorine donor may be ferric or sulfur chloride. The liquid fused salt bath is made up of chlorides of alkali metals, alkaline earth metals, ammonia, zinc and ferric iron. Because the formed metal chlorides are soluble in the liquid fused salt bath, they can be recovered by various conventional means

  7. Ecological effect of rare earth elements

    International Nuclear Information System (INIS)

    Hu Aitang; Zhou Quansuo; Zheng Shaojian; Zhai Hai; Zhao Xiulan; Pang Yonglin; Wang Yuqi; Sun Jingxin; Zhang Shen; Wang Lijun

    1997-01-01

    Water and soil culture were carried out to study the ecological effect of rare earth elements (REEs) in the aspect of plant-soil system. Contents of REEs were determined by instrumental neutron activation analysis (INAA). There was a limit to REEs-tolerance of crops, which differed with the development periods of plant and soil types. The REEs concentration in plant, especially in root, was marked related to the concentration in culture material. Beyond the concentration-limit appeared phototoxicity. The chemical behavior of REEs in plants and soils varied with soil types and elements. The bio-availability of REEs in soil mainly depended on the exchangeable fraction of REEs affected strongly by the physi-chemical properties of soils

  8. Processing of monazite at the rare earth division,Udyogamandal

    International Nuclear Information System (INIS)

    Narayanan, N.S.; Thulasidoss, S.; Ramachandran, T.V.; Swaminathan, T.V.; Prasad, K.R.

    1988-01-01

    The processing techniques adopted at the Rare Earth Division of the Indian Rare Earths Limited at Udyogamandal, for the production of rare earth compounds of various compositions and purity grades are reviewed. Over 100 different compounds are produced and marketed, and these include mixed rare earths chloride, crude thorium concentrate, cerium oxide, cerium hydrate, rare earths carbonate, didymium salts and individual rare earth oxides and salts. Also, the trisodium phosphate obtained as byproduct in the processing of monazite, is recovered and marketed. The process scheme for monazite essentially involves alkaline digestion of ground monazite, removal of the by-product trisodium phosphate, separation of thorium through preferential dissolution of rare earths hydroxide in hydrochloric acid under controlled pH and temperature conditions followed by purification, and evaporation of the chloride solution to yield pure rare earths chloride. Part of the chloride is utilised for the production of individual rare earth compounds after separation by solvent extraction and ion exchange processes. Individual rare earth compounds of 99.99 %+ purity are regularly produced to cater to the demand within the country. (author) 8 figs., 1 tab

  9. Magnetic properties of rare-earth intermetallics

    International Nuclear Information System (INIS)

    Kirchmayr, H.

    1978-01-01

    A review is given of the concepts at present used to explain the magnetic properties of rare-earth intermetallics which have been the subject of numerous investigations in recent years. Rare-earth intermetallics with the formula Rsub(a)Bsub(b) are divided according to the magnetic moment of the B atom(s). If there is no magnetic moment present at the B-site, the exchange is only between the magnetic moments at the R-sites, which can only be of indirect character. One possible model is still the RKKY model, although it usually gives in practice only a qualitative description of the magnetic properties. Typical R-B compounds with the B-moment equal to zero are (for instance) the RA1 2 compounds, and related compounds such as the RZn and RCd compounds as well as compounds of the general formula RB 2 (B = Ni, Os, Ir, Pd, Ru or Rh). Of all intermetallics with nonzero B-moment, the R-3d intermetallics are the most important. These intermetallics can be formed with Mn, Fe, Co and Ni. In these systems there exist in principle three interactions, namely between the R-R, R-3d and 3d-3d atoms. The most important is usually the latter interaction. After a short discussion of the crystal structures which occur with R-3d intermetallics, the basic magnetic properties of R-3d intermetallics are presented. These properties are discussed with respect to the formation of a magnetic moment at the 3d site in the framework of present band theories. Special emphasis is given to a discussion of the localized or itinerant character of 3d electrons. (author)

  10. Real and complex boson expansions in even-even deformed nuclei

    International Nuclear Information System (INIS)

    Silvestre-Brac, B.; Piepenbring, R.

    1977-01-01

    Analysis of real and complex boson expansions of the Kishimoto-Tamura type is performed in a deformed basis in order to allow a further study of the anharmonicities of vibrations in deformed nuclei. It is shown that complex solutions cannot be found in the cases where no real one exists. (Auth.)

  11. K isomerism and collectivity in neutron-rich rare-earth isotopes

    Science.gov (United States)

    Patel, Zena

    Neutron-rich rare-earth isotopes were produced by in-flight fission of 238U ions at the Radioactive Isotope Beam Factory (RIBF), RIKEN, Japan. In-flight fission of a heavy, high-intensity beam of 238U ions on a light target provides the cleanest secondary beams of neutron-rich nuclei in the rare-earth region of isotopes. In-flight fission is advantageous over other methods of nuclear production, as it allows for a secondary beam to be extracted, from which the beam species can be separated and identified. The excited states of nuclei are studied by delayed isomeric or beta-delayed gamma-ray spectroscopy. New K isomers were found in Sm (Z=62), Eu (Z=63), and Gd (Z=64) isotopes. The key results are discussed here. Excited states in the N=102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time. The K-isomeric states in 166Gd and 164Sm are due to 2-quasiparticle configurations. Based on the decay patterns and potential energy surface calculations, including beta6 deformation, both isomers are assigned a (6-) spin-parity. The half-lives of the isomeric states have been measured to be 950(60)ns and 600(140)ns for 166Gd and 164Sm respectively. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground state band energies of 166Gd and 164Sm (N=102) compared to 164Gd and 162Sm (N=100) respectively, presents evidence for the predicted deformed shell closure at N=100. A 4-quasiparticle isomeric state has been discovered in 160Sm: the lightest deformed nucleus with a 4-quasiparticle isomer to date. The isomeric state is assigned an (11+) spin-parity with a measured half-life of 1.8(4)us. The (11+) isomeric state decays into a rotational band structure, based on a (6-) v5/2-[523] ⊗ v7/2+[633] bandhead, determined from the extracted gK-gR values. Potential energy surface and blocked BCS calculations were performed in the deformed midshell region

  12. Study of ^{14}C Cluster Decay Half-Lives of Heavy Deformed Nuclei

    Science.gov (United States)

    Shamami, S. Rahimi; Pahlavani, M. R.

    2018-01-01

    A theoretical model based on deformed Woods-Saxon, Coulomb and centrifugal terms are constructed to evaluate the half-lives for the cluster radioactivity of various super heavy nuclei. Deformation have been applied on all parts of their potential containing nuclear barrier for cluster decay. Also, both parent and daughter nuclei are considered to be deformed. The calculated results of ^{14}C cluster radioactivity half-lives are compared with available experimental data. A satisfactory agreement between theoretical and measured data is achieved. Also, obtained half-lives for each decay family is agreed with Geiger-Nuttall law.

  13. Enhanced pinning in mixed rare earth-123 films

    Science.gov (United States)

    Driscoll, Judith L [Los Alamos, NM; Foltyn, Stephen R [Los Alamos, NM

    2009-06-16

    An superconductive article and method of forming such an article is disclosed, the article including a substrate and a layer of a rare earth barium cuprate film upon the substrate, the rare earth barium cuprate film including two or more rare earth metals capable of yielding a superconductive composition where ion size variance between the two or more rare earth metals is characterized as greater than zero and less than about 10.times.10.sup.-4, and the rare earth barium cuprate film including two or more rare earth metals is further characterized as having an enhanced critical current density in comparison to a standard YBa.sub.2Cu.sub.3O.sub.y composition under identical testing conditions.

  14. Production of rare earth-silicon-iron alloys

    International Nuclear Information System (INIS)

    Mehra, O.K.; Bose, D.K.; Gupta, C.K.

    1987-01-01

    At Metallurgy Division, BARC, improved procedures for producing rare earth-silicon alloys have been investigated. In these methods, reduction of mixed rare earth oxide by a ferro-silicon and aluminium mixture in combination with CaO-MgO flux/CaO-CaF 2 flux have been tried to prepare an alloy product with a higher rare earth recovery at a higher rare earth content than the present commercial production method. The rare earth recovery using CaO-CaF 2 was 85 per cent while in the case of CaO-MgO flux it was 76 per cent. The corresponding rare earth contents in the alloy correspond to 40 per cent and 55 per cent by weight respectively. (author)

  15. A study on dehydration of rare earth chloride hydrate

    International Nuclear Information System (INIS)

    Cho, Yong Zun; Eun, Hee Chul; Son, Sung Mo; Lee, Tae Kyo; Hwang, Taek Sung

    2012-01-01

    The dehydration schemes of rare earth (La, Ce, Nd, Pr, Sm. Eu, Gd, Y) chloride hydrates was investigated by using a dehydration apparatus. To prevent the formation of the rare earth oxychlorides, the operation temperature was changed step by step (80→150→230 degree C) based on the TGA (thermo-gravimetric analysis) results of the rare earth chloride hydrates. A vacuum pump and preheated Ar gas were used to effectively remove the evaporated moisture and maintain an inert condition in the dehydration apparatus. The dehydration temperature of the rare earth chloride hydrate was increased when the atomic number of the rare earth nuclide was increased. The content of the moisture in the rare earth chloride hydrate was decreased below 10% in the dehydration apparatus.

  16. Leaching of rare earth elements from bentonite clay

    OpenAIRE

    van der Watt, J.G; Waanders, F.B

    2012-01-01

    Due to increasing concerns of global rare earth element shortfalls in the near future, possible alternative sources of rare earth elements have recently become of economic interest. One such alternative is decanting acid mine water originating primarily from abandoned old mines in the Witwatersrand region of the Republic of South Africa. In this study, a novel way of rare earth element removal from the acid mine drainage was employed, making use of bentonite clay, which has very good adsorben...

  17. Enzymatic determination of rare earth elements using pyrophosphatases

    International Nuclear Information System (INIS)

    Shekhovtsova, T.N.; Pirogova, S.V.; Fedorova, O.M.; Dolmanova, I.F.; Bajkov, A.A.

    1993-01-01

    A highly sensitive(determination limit 8x10 -6 -4x10 -4 μ g/m) and selective enzymatic method for determination of rare earth elements has been developed. The method is based on inhibition action of rare earths on the catalytic activity of pyrophosphates isolated from bakery geast and E.Coli. The mechanism of the rare earth element action, corresponding to competitive inhibition, has been established

  18. Enzymatic determination of rare earth elements by use of pyrophosphotases

    International Nuclear Information System (INIS)

    Shekhovtseva, T.N.; Pirogova, S.V.; Fedorova, O.M.; Dolmanova, I.F.; Bajkov, A.A.

    1993-01-01

    A highly sensitive (determination limit 8 x 10 -6 - 4 x 10 -4 μg/ml) and selective enzymatic method for determination of rare earth elements has been developed. The method is based on inhibition action of rare earths on the catalytic activity of pyrophosphates isolated from bakery geast and E. Coli. The mechanism of the rare earth element action, corresponding to competitive inhibition, has been established

  19. Contributions to the rare earths to science and technology

    International Nuclear Information System (INIS)

    Spedding, F.H.

    1975-01-01

    This is a brief summary of some areas of science where the rare earths have already played an important role and of other areas where they are almost certain to be helpful. The discovery, abundance, separation, and properties of rare earths are discussed. It is pointed out that the rare earths comprise almost one-fourth of the known metals, and their alloys a third of the possible alloys

  20. Distribution characteristics of rare earth elements in plants from a rare earth ore area

    International Nuclear Information System (INIS)

    Zhang, Z.Y.; Wang, Y.Q.; Li, F.L.; Xiao, H.Q.; Chai, Z.F.

    2002-01-01

    The contents of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in various plant species taken from a rare earth ore area were determined by instrumental neutron activation analysis. For a given plant, the REE patterns in root, leaf and host soil are different from each other. The REE distribution characteristics in roots of various species are very similar and resemble those in the surface water. The results of this study suggest that there is no significant fractionation between the REEs during their uptake by the plant roots from soil solution. However, the variation of the relative abundance of individual REE occurs in the process of transportation and deposition of REEs in plants. (author)

  1. Cermets based on rhenium and rare earth element oxides

    International Nuclear Information System (INIS)

    Varfolomeev, M.B.; Velichko, A.V.; Zajtseva, L.L.; Shishkov, N.V.

    1977-01-01

    The reduction of perrhenates of rare earth elements and of yttrium by hydrogen and the subsequent sintering have yielded cermets based on rhenium and rare earth element oxides inherent in which are more disperse and homogeneous structures than those of the ''molecular'' rare earth element-Tc cermets. The dispersity of cermets increases in the rare earth elements series from La to Lu. The microhardness of the Re phase in cermets is 490 kgf/mm 2 ; the total microhardness of a cermet is substantially higher

  2. Rare earths in iron and steelmaking and gaseous desulphurisation

    International Nuclear Information System (INIS)

    Kay, D.A.R.; Subramanian, S.V.; Meng, V.; Kumar, R.V.

    1985-01-01

    Rare earth (RE) additions, either as mischmetal or rare earth silicide, are used in many ladle treatment processes in modern ferrous metallurgy. In ironmaking they provide the basis for the control of graphite morphology in cast irons and in steelmaking additions are made to aluminum-killed steels for desulphurisation and the control of inclusion composition and morphology. Rare earth oxides may also be used in the desulphurisation of medium calorific value gaseous fuels and stack gases. In this paper, Ce-S-O and La-S-O phase stability diagrams are used to determine the role of the rare earths in the external processing of iron and steel, and gaseous desulphurisation

  3. Rare earth impact on glass structure and alteration kinetics

    International Nuclear Information System (INIS)

    Molieres, E.

    2012-01-01

    This work is related to the question of the geological deep repository of high-level waste glass. These wastes include fission products and minor actinides, elements which can be simulated by rare earths. As new glass compositions could enable increased rare earth concentrations, it is crucial to know and understand rare earth impact on glass structure on the one hand, and on glass alteration kinetics or their incorporation into an altered layer. This work studied simplified borosilicate glasses in order to limit synergetic effects between rare earths and other elements. Various complementary techniques were used to characterize pristine and altered glasses (solid-high resolution NMR, Raman spectroscopy, fluorescence, SIMS, SAXS). Firstly, the structural role of a rare earth is discussed and is compared to a calcium cation. The local environment of rare earths is also probed. Secondly, rare earth (nature and concentration) impact on several alteration regimes was studied (initial rate, rate drop). Then, after alteration, rare earth elements being retained within the altered layer, the structural impact of rare earth elements (and their local environment) in this alteration layer was also investigated. (author) [fr

  4. Iron corrosion inhibition by phosphonate complexes of rare earth metals

    International Nuclear Information System (INIS)

    Kuznetsov, Yu.I.; Raskol'nikov, A.F.; Starobinskaya, I.V.; Alekseev, V.N.

    1993-01-01

    Capability is shown of trivalent rare earth nitrilotrimethylphosphonates (R= Ce, Pr, Nd, Eu, Lu, Y) to retard steel corrosion in soft water due to the formation of slightly soluble hydroxides on steel surface. The protective film is produced as a result of electrophilic substitution of nascent iron cations for rare earth ions in near the surface layer. The introduction of rare earth cations into the protective film is ascertained by Auger spectroscopy in combination with the argon spraying. A quantitative interrelation between the protective effectiveness and solubility product of rare earth hydroxides is revealed

  5. Rare earth element abundances and distribution patterns in plant materials

    International Nuclear Information System (INIS)

    Aidid, S.B.

    1994-01-01

    Eight out of the fourteen rare earth elements were estimated from the leaves of Pelthophorum pterocarpum, the leaves and roots of Impatiens balsamina, and the soils from four sampling sites by instrumental neutron activation analysis. The chondrite normalized rare earth element abundances and distribution patterns in the plant materials were found to be significantly correlated to the abundances of the rare earth elements occurring in the soils. The extent of accumulation of the rare earth elements in some plant materials was also governed by the age of the plants and the plant organs. (author) 16 refs.; 4 figs.; 3 tabs

  6. Search for shape coexistence in odd - Z rare earth proton emitters

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2015-01-01

    Nuclear shapes are very sensitive to the structural effects and can change with isospin and from one nucleus to its neighbour and in some cases configurations corresponding to different shapes may coexist at similar energies which may arise from intruder excitations. Search for such interesting phenomena of shape coexistence and rapidly changing shapes in the less explored region of rare earth odd Z nuclei from Z = 51 to 75 are the focus of present work

  7. The Rare Earth Magnet Industry and Rare Earth Price in China

    Science.gov (United States)

    Ding, Kaihong

    2014-07-01

    In the past four years, the price of rare earth metal fluctuates sharply for many reasons. Currently, it has become more stable and more reasonable. This presentation is focused on the effect about the rare earth metal price. Some motor manufacturers have shifted from rare earth permanent magnet to ferrite magnet. Many motor manufacturers changed the design for the motor cooling system to make the motor function at a lower temperature. Thus the consumption of Dy can be markedly reduced. As for manufacturer of NdFeB magnet, we are also trying to optimize our process to reduce to dependence of HREE such as Dy and Tb. HS process have been introduced to solve the problem. With more and more people focusing and engaging on the REE industry, the price of REE will be more transparent without too many fluctuations. China is considering the problems of balancing the environment, energy sources, and labor sources. The application field about NdFeB such as wind turbine generator, HEV/EV, FA /OA is flourishing.

  8. The Rare Earth Magnet Industry and Rare Earth Price in China

    Directory of Open Access Journals (Sweden)

    Ding Kaihong

    2014-07-01

    Full Text Available In the past four years, the price of rare earth metal fluctuates sharply for many reasons. Currently, it has become more stable and more reasonable. This presentation is focused on the effect about the rare earth metal price. Some motor manufacturers have shifted from rare earth permanent magnet to ferrite magnet. Many motor manufacturers changed the design for the motor cooling system to make the motor function at a lower temperature. Thus the consumption of Dy can be markedly reduced. As for manufacturer of NdFeB magnet, we are also trying to optimize our process to reduce to dependence of HREE such as Dy and Tb. HS process have been introduced to solve the problem. With more and more people focusing and engaging on the REE industry, the price of REE will be more transparent without too many fluctuations. China is considering the problems of balancing the environment, energy sources, and labor sources. The application field about NdFeB such as wind turbine generator, HEV/EV, FA /OA is flourishing.

  9. Rare earth silicide nanowires on silicon surfaces

    International Nuclear Information System (INIS)

    Wanke, Martina

    2008-01-01

    The growth, structure and electronic properties of rare earth silicide nanowires are investigated on planar and vicinal Si(001) und Si(111) surfaces with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy (ARPES). On all surfaces investigated within this work hexagonal disilicides are grown epitaxially with a lattice mismatch of -2.55% up to +0.83% along the hexagonal a-axis. Along the hexagonal c-axis the lattice mismatch is essentially larger with 6.5%. On the Si(001)2 x 1 surface two types of nanowires are grown epitaxially. The socalled broad wires show a one-dimensional metallic valence band structure with states crossing the Fermi level. Along the nanowires two strongly dispersing states at the anti J point and a strongly dispersing state at the anti Γ point can be observed. Along the thin nanowires dispersing states could not be observed. Merely in the direction perpendicular to the wires an intensity variation could be observed, which corresponds to the observed spacial structure of the thin nanowires. The electronic properties of the broad erbium silicide nanowires are very similar to the broad dysprosium silicide nanowires. The electronic properties of the DySi 2 -monolayer and the Dy 3 Si 5 -multilayer on the Si(111) surface are investigated in comparison to the known ErSi 2 /Si(111) and Er 3 Si 5 /Si(111) system. The positions and the energetic locations of the observed band in the surface Brillouin zone will be confirmed for dysprosium. The shape of the electron pockets in the vector k parallel space is elliptical at the anti M points, while the hole pocket at the anti Γ point is showing a hexagonal symmetry. On the Si(557) surface the structural and electronic properties depend strongly on the different preparation conditions likewise, in particular on the rare earth coverage. At submonolayer coverage the thin nanowires grow in wide areas of the sample surface, which are oriented

  10. Rare earth-ruthenium-magnesium intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Sebastian; Kersting, Marcel; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-07-01

    Eight new intermetallic rare earth-ruthenium-magnesium compounds have been synthesized from the elements in sealed niobium ampoules using different annealing sequences in muffle furnaces. The compounds have been characterized by powder and single crystal X-ray diffraction. Sm{sub 9.2}Ru{sub 6}Mg{sub 17.8} (a=939.6(2), c=1779(1) pm), Gd{sub 11}Ru{sub 6}Mg{sub 16} (a=951.9(2), c=1756.8(8) pm), and Tb{sub 10.5}Ru{sub 6}Mg{sub 16.5} (a=942.5(1), c=1758.3(4) pm) crystallize with the tetragonal Nd{sub 9.34}Ru{sub 6}Mg{sub 17.66} type structure, space group I4/mmm. This structure exhibits a complex condensation pattern of square-prisms and square-antiprisms around the magnesium and ruthenium atoms, respectively. Y{sub 2}RuMg{sub 2} (a=344.0(1), c=2019(1) pm) and Tb{sub 2}RuMg{sub 2} (a=341.43(6), c=2054.2(7) pm) adopt the Er{sub 2}RuMg{sub 2} structure and Tm{sub 3}Ru{sub 2}Mg (a=337.72(9), c=1129.8(4) pm) is isotypic with Sc{sub 3}Ru{sub 2}Mg. Tm{sub 3}Ru{sub 2}Mg{sub 2} (a=337.35(9), c=2671(1) pm) and Lu{sub 3}Ru{sub 2}Mg{sub 2} (a=335.83(5), c=2652.2(5) pm) are the first ternary ordered variants of the Ti{sub 3}Cu{sub 4} type, space group I4/mmm. These five compounds belong to a large family of intermetallics which are completely ordered superstructures of the bcc subcell. The group-subgroup scheme for Lu{sub 3}Ru{sub 2}Mg{sub 2} is presented. The common structural motif of all three structure types are ruthenium-centered rare earth cubes reminicent of the CsCl type. Magnetic susceptibility measurements of Y{sub 2}RuMg{sub 2} and Lu{sub 3}Ru{sub 2}Mg{sub 2} samples revealed Pauli paramagnetism of the conduction electrons.

  11. Improved Rare-Earth Emitter Hollow Cathode

    Science.gov (United States)

    Goebel, Dan M.

    2011-01-01

    An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out

  12. Collective states of nonspherical deformable even--even nuclei

    International Nuclear Information System (INIS)

    Tartakovskii, V.K.

    1989-01-01

    A more correct method, as compared with some earlier studies, of finding the wave functions and corresponding energies of longitudinal quadrupole vibrations of nonspherical even--even nuclei is proposed. The wave functions and energies of collective motions in nuclei have been obtained in explicit form for a number of dependences of the potential energy of longitudinal vibrations V(β), including the dependence V(β), not previously used, of the most general form. Explicit dependences of the potential energy of transverse vibrations and the corresponding wave functions and eigenvalues for nuclear states with zero spins are proposed

  13. Ion exchange separation of rare earths. I

    International Nuclear Information System (INIS)

    Nghi, Nguyen danh; Matous, K.

    1977-01-01

    The optimal conditions of separating selected rare earths by two ion exchange chromatography using Ostion KS cation exchange resin were studied. The effect of acetic acid concentration in the sorption solution was investigated. The elution process was studied in dependence on the concentration of Na 2 H 2 EDTA, on the total concentration of EDTA 4- ion, on elution agent flow, and on temperature. The optimal conditions were determined by evaluating integral elution curves and changes in acid concentration for systems Y-Pr, La-Pr, Er-Pr, Eu-Pr as follows: The sorption solution requires the presence of Na 2 H 2 EDTA of 0.03M in concentration. The basic elution solution was prepared in the following way: 0.183M Na 2 Mg 2 EDTA, 9.6x10 -3 M Na 2 H 2 EDTA, 3.84x10 -3 M CH 3 COOH, 2.30x10 -2 M CH 3 COONH 4 , 2.30x10 -2 M (NH 4 ) 2 SO 4 . Approximate pH 5.7 to 6.0. The optimal elution solution was prepared by diluting the basic solution so that the total concentration of EDTA 4- equalled 0.075M. The optimal flow was determined to be 0.86 ml.cm -2 .min -1 at a temperature of 55 degC. (author)

  14. Rare-earth-doped fluorozirconate fiber lasers

    International Nuclear Information System (INIS)

    Brierly, M.C.; France, P.W.; Moore, M.W.; Davey, S.T.

    1988-01-01

    Rare-earth-doped fiber lasers fabricated using silica-based fibers are rapidly becoming an established technology. Simultaneously, in the search for lower losses to achieve longer repeaterless communications links, another fiber technology based on fluorozirconate glasses is emerging. Fluorozirconate glass systems are known to be suitable laser hosts, and the authors have already reported Nd-doped fiber lasers using this technology. Recently the authors have used a 0.5-m length of 44-μm core fluorozirconate fiber doped with 1000 ppm of Nd 3+ ions in a longitudinally pumped Fabry-Perot cavity with a 90% output coupler. They observed lasing at 1.05 μm with a threshold of 33-mW launched power at 514 nm and a slope efficiency of 16.8%. The authors attribute this improvement to the higher dopant concentration, better fiber to mirror coupling, and more optimum output coupler reflectivity. In addition the same fiber used with two high-reflector mirrors at 1.35μm produced lasing at 1.35μm with a threshold of 60-mW launched power

  15. Rare Earth Element Phases in Bauxite Residue

    Directory of Open Access Journals (Sweden)

    Johannes Vind

    2018-02-01

    Full Text Available The purpose of present work was to provide mineralogical insight into the rare earth element (REE phases in bauxite residue to improve REE recovering technologies. Experimental work was performed by electron probe microanalysis with energy dispersive as well as wavelength dispersive spectroscopy and transmission electron microscopy. REEs are found as discrete mineral particles in bauxite residue. Their sizes range from <1 μm to about 40 μm. In bauxite residue, the most abundant REE bearing phases are light REE (LREE ferrotitanates that form a solid solution between the phases with major compositions (REE,Ca,Na(Ti,FeO3 and (Ca,Na(Ti,FeO3. These are secondary phases formed during the Bayer process by an in-situ transformation of the precursor bauxite LREE phases. Compared to natural systems, the indicated solid solution resembles loparite-perovskite series. LREE particles often have a calcium ferrotitanate shell surrounding them that probably hinders their solubility. Minor amount of LREE carbonate and phosphate minerals as well as manganese-associated LREE phases are also present in bauxite residue. Heavy REEs occur in the same form as in bauxites, namely as yttrium phosphates. These results show that the Bayer process has an impact on the initial REE mineralogy contained in bauxite. Bauxite residue as well as selected bauxites are potentially good sources of REEs.

  16. Wine Traceability with Rare Earth Elements

    Directory of Open Access Journals (Sweden)

    Maurizio Aceto

    2018-03-01

    Full Text Available The traceability of foodstuffs is now a relevant aspect of the food market. Scientific research has been devoted to addressing this issue by developing analytical protocols in order to find the link between soil and food items. In this view, chemical parameters that can act as soil markers are being sought. In this work, the role of rare earth elements (REEs as geochemical markers in the traceability of red wine is discussed. The REE distribution in samples from each step of the wine making process of Primitivo wine (produced in Southern Italy was determined using the highly sensitive inductively coupled plasma-mass spectrometry (ICP-MS technique. Samples analyzed include grapes, must, and wine samples after every step in the vinification process. The resulting data were compared to the REE distribution in the soil, revealing that the soil fingerprint is maintained in the intermediate products up to and including grape must. Fractionation occurs thereafter as a consequence of further external interventions, which tends to modify the REE profile.

  17. Double Solvent for Extracting Rare Earth Concentrate

    International Nuclear Information System (INIS)

    Bintarti, AN; Bambang EHB

    2007-01-01

    An extraction process to rare earth concentrate which contain elements were yttrium (Y), lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), gadolinium (Gd) and dysprosium (Dy) which were dissolved in to nitric acid has been done. The experiment of the extraction by double solvent in batch to mix 10 ml of the feed with 10 ml solvent contained the pair of solvent was TBP and TOA, D2EHPA and TOA, TBP and D2EHPA in cyclohexane as tinner. It was selected a right pairs of solvent for doing variation such as the acidity of the feed from 2 - 6 M and the time of stirring from 5 - 25 minutes gave the good relatively extraction condition to Dy element such as using 10 % volume of TOA in D2EHPA and cyclohexane, the acidity of the feed 3 M and the time stirring 15 minutes produced coefficient distribution to dysprosium = 0.586 and separation factor Dy-Ce = ∼ (unlimited); Dy-Nd = 4.651. (author)

  18. Chromatographic Techniques for Rare Earth Elements Analysis

    Science.gov (United States)

    Chen, Beibei; He, Man; Zhang, Huashan; Jiang, Zucheng; Hu, Bin

    2017-04-01

    The present capability of rare earth element (REE) analysis has been achieved by the development of two instrumental techniques. The efficiency of spectroscopic methods was extraordinarily improved for the detection and determination of REE traces in various materials. On the other hand, the determination of REEs very often depends on the preconcentration and separation of REEs, and chromatographic techniques are very powerful tools for the separation of REEs. By coupling with sensitive detectors, many ambitious analytical tasks can be fulfilled. Liquid chromatography is the most widely used technique. Different combinations of stationary phases and mobile phases could be used in ion exchange chromatography, ion chromatography, ion-pair reverse-phase chromatography and some other techniques. The application of gas chromatography is limited because only volatile compounds of REEs can be separated. Thin-layer and paper chromatography are techniques that cannot be directly coupled with suitable detectors, which limit their applications. For special demands, separations can be performed by capillary electrophoresis, which has very high separation efficiency.

  19. HfO2 - rare earth oxide systems in the region with high content of rare earth oxide

    International Nuclear Information System (INIS)

    Shevchenko, A.V.; Lopato, L.M.

    1982-01-01

    Using the methods of annealing and hardenings (10 2 -10 4 deg/s cooling rate) and differential thermal analysis elements of state diagrams of HfO 2 - rare earth oxide (rare earths-La, Pr, Nd, Sm, Gd, Tb, Dy, Y, Er, Yb, Lu, Sc) systems from 1800 deg C up to melting in the range of 60-100 mol% rare earth oxide concentration were constructed. Regularities of HfQ 2 addition effect on high-temperature polymorphic transformations of rare earth oxides were studied. Results of investigation were discussed from viewpoint of crystal chemistry

  20. Magnetostriction of rare earth-Fe2 Laves phase compounds

    International Nuclear Information System (INIS)

    Clark, A.E.; Abbundi, R.; Savage, H.T.

    1977-01-01

    Single crystal magnetostriction measurements were made as a function of temperature on TbFe 2 and DyFe 2 . From these, the intrinsic magnetoelastic coupling coefficients were determined for the rare earth-Fe 2 compounds. Employing X-ray techniques, certain multicomponent rare earth-Fe 2 compounds were identified to maximize the magnetostriction to anisotropy ratio. (Auth.)

  1. Preparation, thermogravimetric study and infrared spectra of rare earth acetates

    International Nuclear Information System (INIS)

    Graehlert, X.; Starke, M.

    1992-01-01

    The anhydrous and the hydrated acetates of Ho, Er, Tm, Yb and Lu have been prepared. The compounds obtained have been investigated by thermogravimetric analysis and infrared spectroscopy. The thermal decomposition of the rare earth acetates may proceed via various steps. It depends on both the number of crystal water molecules in the acetates and the rare earth element's behaviour. (orig.)

  2. Advances in chromatography of the rare earth elements (review)

    International Nuclear Information System (INIS)

    Oguma, Koichi; Kuroda, Rokuro; Shimizu, Tsuneo.

    1995-01-01

    A review is presented which covers liquid chromatography, gas chromatography, and related techniques. This article intends to describe the chromatographic methods playing an important role in the separation of the rare earth elements. Special attention is paid to the usefulness of various types of liquid chromatography which enable the complete mutual separation of the rare earth elements. Applications are also discussed. (author) 161 refs

  3. Replacing critical rare earth materials in high energy density magnets

    Science.gov (United States)

    McCallum, R. William

    2012-02-01

    High energy density permanent magnets are crucial to the design of internal permanent magnet motors (IPM) for hybride and electric vehicles and direct drive wind generators. Current motor designs use rare earth permanent magnets which easily meet the performance goals, however, the rising concerns over cost and foreign control of the current supply of rare earth resources has motivated a search for non-rare earth based permanent magnets alloys with performance metrics which allow the design of permanent magnet motors and generators without rare earth magnets. This talk will discuss the state of non-rare-earth permanent magnets and efforts to both improve the current materials and find new materials. These efforts combine first principles calculations and meso-scale magnetic modeling with advance characterization and synthesis techniques in order to advance the state of the art in non rare earth permanent magnets. The use of genetic algorithms in first principle structural calculations, combinatorial synthesis in the experimental search for materials, atom probe microscopy to characterize grain boundaries on the atomic level, and other state of the art techniques will be discussed. In addition the possibility of replacing critical rare earth elements with the most abundant rare earth Ce will be discussed.

  4. Separation of rare earths from solutions of phosphoric acid

    International Nuclear Information System (INIS)

    Jones, E.A.

    1977-01-01

    Rare earths are separated from 6M phosphoric acid by adsorption onto cation resin BIORAD AG50W-X8. The phosphoric acid is then washed from the column, and the rare earths are eluted with 4M hydrochloric acid

  5. Effects of high-order deformation on high-K isomers in superheavy nuclei

    International Nuclear Information System (INIS)

    Liu, H. L.; Bertulani, C. A.; Xu, F. R.; Walker, P. M.

    2011-01-01

    Using, for the first time, configuration-constrained potential-energy-surface calculations with the inclusion of β 6 deformation, we find remarkable effects of the high-order deformation on the high-K isomers in 254 No, the focus of recent spectroscopy experiments on superheavy nuclei. For shapes with multipolarity six, the isomers are more tightly bound and, microscopically, have enhanced deformed shell gaps at N=152 and Z=100. The inclusion of β 6 deformation significantly improves the description of the very heavy high-K isomers.

  6. Rare earth silicide nanowires on silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Martina

    2008-11-10

    The growth, structure and electronic properties of rare earth silicide nanowires are investigated on planar and vicinal Si(001) und Si(111) surfaces with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy (ARPES). On all surfaces investigated within this work hexagonal disilicides are grown epitaxially with a lattice mismatch of -2.55% up to +0.83% along the hexagonal a-axis. Along the hexagonal c-axis the lattice mismatch is essentially larger with 6.5%. On the Si(001)2 x 1 surface two types of nanowires are grown epitaxially. The socalled broad wires show a one-dimensional metallic valence band structure with states crossing the Fermi level. Along the nanowires two strongly dispersing states at the anti J point and a strongly dispersing state at the anti {gamma} point can be observed. Along the thin nanowires dispersing states could not be observed. Merely in the direction perpendicular to the wires an intensity variation could be observed, which corresponds to the observed spacial structure of the thin nanowires. The electronic properties of the broad erbium silicide nanowires are very similar to the broad dysprosium silicide nanowires. The electronic properties of the DySi{sub 2}-monolayer and the Dy{sub 3}Si{sub 5}-multilayer on the Si(111) surface are investigated in comparison to the known ErSi{sub 2}/Si(111) and Er{sub 3}Si{sub 5}/Si(111) system. The positions and the energetic locations of the observed band in the surface Brillouin zone will be confirmed for dysprosium. The shape of the electron pockets in the (vector)k {sub parallel} space is elliptical at the anti M points, while the hole pocket at the anti {gamma} point is showing a hexagonal symmetry. On the Si(557) surface the structural and electronic properties depend strongly on the different preparation conditions likewise, in particular on the rare earth coverage. At submonolayer coverage the thin nanowires grow in wide areas

  7. Single particle Schroedinger fluid and moments of inertia of deformed nuclei

    International Nuclear Information System (INIS)

    Doma, S.B.

    2002-01-01

    The authors have applied the theory of the single-particle Schroedinger fluid to the nuclear collective motion of axially deformed nuclei. A counter example of an arbitrary number of independent nucleons in the anisotropic harmonic oscillator potential at the equilibrium deformation has been also given. Moreover, the ground states of the doubly even nuclei in the s-d shell 20 Ne, 24 Mg, 28 Si, 32 S and 36 Ar are constructed by filling the single-particle states corresponding to the possible values of the number of quanta of excitations n x , n y and n z . Accordingly, the cranking-model, the rigid-body model and the equilibrium-model moments of inertia of these nuclei are calculated as functions of the oscillator parameters ℎω x , ℎω y and ℎω z which are given in terms of the non deformed value ℎω 0 0 , depending on the mass number A, the number of neutrons N, the number of protons Z, and the deformation parameter β. The calculated values of the cranking-model moments of inertia of these nuclei are in good agreement with the corresponding experiential values and show that the considered axially deformed nuclei may have oblate as well as prolate shapes and that the nucleus 24 Mg is the only one which is highly deformed. The rigid-body model and the equilibrium-model moments of inertia of the two nuclei 20 Ne and 24 Mg are also in good agreement with the corresponding experimental values

  8. Kinetics studies of solvent extraction of rare earths into DEHPA

    International Nuclear Information System (INIS)

    Lim, T.M.; Tran, T.

    1996-01-01

    The kinetics of rare earth solvent extraction into di(2-ethylhexyl) phosphoric acid have been studied using radiotracers ( 141 Ce, 152 Eu, 153 Gd, 160 Tb and 88 Y) in a modified Lewis cell. The experimental procedure involved continuous monitoring of both aqueous and organic phases using an automated γ- counting system. Using this method, highly reproducible results were obtained without chemical analysis or disturbance of the system. The initial rate extraction was first order with respect to individual rare earth concentration. At low acidities ([H+] < 0.01 M), the extraction rates of rare earths were equal and independent of pH. However, at high acidities, the extraction rate was strongly dependent on pH and varied between the rare earths. Similarly, differences in the extraction rate of individual rare earths were apparent at low DEHPA concentration. (authors)

  9. PROCESS FOR SEPARATING AMERICIUM AND CURIUM FROM RARE EARTH ELEMENTS

    Science.gov (United States)

    Baybarz, R.D.; Lloyd, M.H.

    1963-02-26

    This invention relates to methods of separating americium and curium values from rare earth values. In accordance with the invention americium, curium, and rare earth values are sorbed on an anion exchange resin. A major portion of the rare earth values are selectively stripped from the resin with a concentrated aqueous solution of lithium chloride, and americium, curium, and a minor portion of rare earth values are then stripped from the resin with a dilute aqueous solution of lithium chloride. The americium and curium values are further purified by increasing the concentration of lithium chloride in the solution to at least 8 molar and selectively extracting rare earth values from the resulting solution with a monoalkylphosphoric acid. (AEC)

  10. Determination of active oxygen content in rare earth peroxides

    International Nuclear Information System (INIS)

    Queiroz, Carlos A.S.; Abrao, Alcidio

    1993-01-01

    The content of active oxygen in rare earth peroxides have been determined after the dissolution of the samples with hydrocloridic acid in the presence of potassium iodide. The free generated iodine is titrated with sodium thiosulfate using starch as indicator. The oxidation of iodide to the free iodine indicates the presence of a higher valence state rare earth oxide, until now specifically recognized for the oxides of cerium (Ce O 2 ), praseodymium (Pr 6 O 1 1) and terbium (TB 4 O 7 ). recently the authors synthesized a new series of rare earth compounds, the peroxides. These new compounds were prepared by precipitating the rare earth elements complexed with carbonate ion by addition of hydrogen peroxide. the authors demonstrated that all rare earth elements, once solubilized by complexing with carbonate ion, are quantitatively precipitated as peroxide by addition of hydrogen peroxide. (author)

  11. Magnetic form factors of rare earth ions

    International Nuclear Information System (INIS)

    Deckman, H.W.

    1976-01-01

    The magnetic scattering of neutrons by atoms has been investigated by exploiting its similarity to the radiation problem in spectroscopy. Expressions for the magnetic scattering amplitude were developed for cases in whcih an atom in the l/sup n/ electronic configuration is described either by a relativistic or nonrelativistic Hamiltonian. For each of these cases, it has been shown that the magnetic scattering amplitude can be expressed in terms of relativistic or nonrelativistic matrix elements of magnetic and electric multipole operators. For a nonrelativistic atom, the calculation of these matrix elements has been separated into evaluating radial matrix elements and matrix elements of Racah tensors W/(sup 0,k)k/ and W/(sup 1,k')k/. For a relativistic atom the effective operator approach has been used to define effective multipole operators so that a relativistic result is obtained by taking matrix elements of these effective operators between nonrelativistic states of the atom. The calculation of matrix elements of these effective operators has been reduced to evaluating relativistic radial integrals and matrix elements of the Racah tensors taken between nonrelativistic states of the atom. It is shown tha for the case of elastic scattering by either a relativistic or nonrelativistic atom in single Russel-Saunders state, the magnetic scattering amplitude can be written in the conventional form p(vector q)vector q/sub m/.vector sigma. General expressions for p(vector q) as well as elastic magnetic form factorshave been obtained. The formalism has been illustrated throughout by applying it to the case of scattering by rare earth ions

  12. Anisotropy of favoured alpha transitions producing even-even deformed nuclei

    International Nuclear Information System (INIS)

    Tavares, O.A.P.

    1997-05-01

    The anisotropy in favoured alpha transitions which produce even-even deformed nuclei is discussed. A simple, Gamow's-like model which takes into account the quadrupole deformation of the product nucleus has been formulated to calculate the alpha decay half-life. It is assumed that before tunneling into a purely Coulomb potential barrier the two-body system oscillated isotropically, thus giving rise to an equivalent, average preferential polar direction θ 0 (referred to the symmetry axis of the ellipsoidal shape of the product nucleus) for alpha emission in favoured alpha transitions of even-even nuclei. (author)

  13. Effects of deformations and orientations on neutron-halo structure of light-halo nuclei

    International Nuclear Information System (INIS)

    Sawhney, Gudveen; Gupta, Raj K.; Sharma, Manoj K.

    2013-01-01

    The availability of radioactive nuclear beams have enabled to study the structure of nuclei far from the stability line, which in turn led to the discovery of neutron-halo nuclei. These nuclei, located near the neutron drip-line exhibit a high probability of presence of one or two loosely bound neutrons at a large distance from the rest of nucleons. The fragmentation behavior is studied for 13 cases of 1n-halo nuclei, which include 11 Be, 14 B, 15 C, 17 C, 19 C, 22 N, 22 O, 23 O, 24 O, 24 F, 26 F, 29 Ne and 31 Ne, using the cluster-core model (CCM) extended to include the deformations and orientations of nuclei

  14. The multiphonon method as a dynamical approach to octupole correlations in deformed nuclei

    International Nuclear Information System (INIS)

    Piepenbring, R.

    1986-09-01

    The octupole correlations in nuclei are studied within the framework of the multiphonon method which is mainly the exact diagonalization of the total Hamiltonian in the space spanned by collective phonons. This treatment takes properly into account the Pauli principle. It is a microscopic approach based on a reflection symmetry of the potential. The spectroscopic properties of double even and odd-mass nuclei are nicely reproduced. The multiphonon method appears as a dynamical approach to octupole correlations in nuclei which can be compared to other models based on stable octupole deformation. 66 refs

  15. Radiological aspects in a monazite based rare earth production facility

    International Nuclear Information System (INIS)

    Harikumar, M.; Sujata, R.; Chinnaesakki, S.; Tripathi, R.M.; Puranik, V.D.; Nair, N.N.G.

    2011-01-01

    One of the largest reserves of monazite in the world is present in the Indian subcontinent. Monazite ore has around 8-9% thorium oxide and nearly 60% Rare earth oxides. Selective acid extraction is used to separate the composite rare earths. The main radiological hazard arises from the presence of thorium and its daughter products. Monitoring of the radiation field and air activity in the rare earths plant is done routinely to reduce the radiation exposure to plant personnel. The separation of uranium and rare earths from Thorium concentrate separated from Monazite is being done as a part of the THRUST (Thorium Retrieval, Recovery of Uranium and Re-storage of Thorium) project from 2004 at Indian Rare Earths Limited, Udyogamandal. The radiological aspect for this extraction of uranium and rare earths was studied. The general radiation field in the rare earth production plant was 0.3-5.0 μGyh -1 and the average short lived air activity was 46 ± 7 mWL. The long lived air activity arising from 232 Th is very insignificant radiologically. The occupational radiation exposure for the rare earths separation plant is only 6 % of the total dose and the estimated average individual dose is 1.6 mSv per year. Studies were also done to estimate the residual radioactivity in the separated rare earth compounds using gamma spectrometry and the results showed significant presence of 227 Ac arising due to the protactinium fraction in the thorium concentrate. This activity is not detectable in a freshly separated rare earth compound but can buildup with time. (author)

  16. Magnetic dipole moments of deformed odd-A nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Garg, V P; Sharma, S D; Mahesh, P S [Punjabi Univ., Patiala (India). Dept. of Physics

    1976-12-01

    Using an extended version of A S Davydov and G F Filippov's model (1958), B E Chi and J P Davidson have calculated magnetic moments of odd-A nuclei in 2s-ld shell, diagonalizing the state matrices for a set of parameters giving the best fit for nuclear spectra (1966). To study the failure of this model in case of nuclear moments, instead of diagonalizing an attempt has been made to simplify the expression for magnetic dipole moment for single nucleonic states without configuration mixing. The model takes care of the proper sign of spin projections. On replacing the total angular momentum j of odd particle (proton or neutron) by its projection ..cap omega.., the expression reduces to that of Mottelson and Nilsson for spin-up nuclei. The Coriolis coupling calculations also have been performed for those odd-A nuclei with K = 1/2. The results are found in better agreement with experimental report in comparison with those of other models.

  17. Rare-earth element geochemistry in the Luanga Mafic-Ultramafic Complex, Para

    International Nuclear Information System (INIS)

    Suita, M.T.F.; Nilson, A.A.

    1989-01-01

    Six whole-rock samples (harzburgite, orthopyroxenic and norite) of the Luanga Mafic-Ultramafic Complex (Para) were analysed for rare-earth elements (REE) through plasma spectrometry. The Luanga Complex is a deformed and metamorphosed layered mafic-ultramafic body of Archaean age. The Complex underwent medium-grade metamorphism in three stages. The first stage (medium grade) involved local formation of tremolite and reduction of Ca content in plagioclase. The second stage (low grade) consisted of serpentinization of amphibole or ortopyroxene forming bastile and generation of albite + epidote + white mica + actinolite from plagioclase. The third stage involved renewed serpentinization and/or talcification of pre-existing minerals (including serpentine) along fracture and fault surfaces. The analysed rocks display light rare-earth element (LREE) enrichment up to sixty times the composition of the Leedly chondrite and La/Yb ratios from 6.2 to 20.0 they are low in medium rare-earth elements (MREE), displaying discrete to strong negative Eu anomaly even in plagioclase cumulates and are slightly enriched in heavy rare-earth elements (HREE), usually higher than chondrite values. The low MREE area related to the occurrence of orthopyroxene (bronzite) in a way similar to the pattern of alpine periodotites, while HREE enrichment is compatible with the presence of bronzite and Mg-olivine, probably an inherited igneous feature. (author) [pt

  18. Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei

    Science.gov (United States)

    Hinde, D. J.; Jeung, D. Y.; Prasad, E.; Wakhle, A.; Dasgupta, M.; Evers, M.; Luong, D. H.; du Rietz, R.; Simenel, C.; Simpson, E. C.; Williams, E.

    2018-02-01

    Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Low excitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near 208Pb, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP=14 . For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP˜8 . Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely

  19. Surface thickness effects and splitting of multipole excitations in deformed nuclei. [Sum rule, hydrodynamic model

    Energy Technology Data Exchange (ETDEWEB)

    Christillin, P [Scuola Normale Superiore, Pisa (Italy); Lipparini, E; Stringari, S [Dipartimento Matematica e Fisica, Trento, Italy

    1978-09-25

    A sum-rule approach is used to study the influence of surface thickness upon the splitting of dipole and isoscalar quadrupole energies in deformed nuclei. It is shown that hydrodynamic model results are recovered in the case of a deformed skin thickness. A constant skin thickness leads in the dipole case to slightly different predictions which seem in better agreement with experiments. The splitting of the isoscalar quadrupole mode is not sensitive to the surface thickness shape.

  20. Effect of the Pauli principle on the nonrotational states in odd-A deformed nuclei

    International Nuclear Information System (INIS)

    Bastrukov, S.I.; Nesterenko, V.O.; Soloviev, V.G.

    1982-01-01

    The commutation relations between the quasiparticle and phonon operators are used to obtain the equations allowing a correct accounting of the Pauli principle for the description of the states of odd-A deformed nuclei. It is shown, that if in the quasiparticle plus phonon component the Pauli principle is not violated or is slightly violated, then a relevant vibrational state may exist in an odd-A deformed nucleus

  1. Bioleaching of rare earth elements from monazite sand.

    Science.gov (United States)

    Brisson, Vanessa L; Zhuang, Wei-Qin; Alvarez-Cohen, Lisa

    2016-02-01

    Three fungal strains were found to be capable of bioleaching rare earth elements from monazite, a rare earth phosphate mineral, utilizing the monazite as a phosphate source and releasing rare earth cations into solution. These organisms include one known phosphate solubilizing fungus, Aspergillus niger ATCC 1015, as well as two newly isolated fungi: an Aspergillus terreus strain ML3-1 and a Paecilomyces spp. strain WE3-F. Although monazite also contains the radioactive element Thorium, bioleaching by these fungi preferentially solubilized rare earth elements over Thorium, leaving the Thorium in the solid residual. Adjustments in growth media composition improved bioleaching performance measured as rare earth release. Cell-free spent medium generated during growth of A. terreus strain ML3-1 and Paecilomyces spp. strain WE3-F in the presence of monazite leached rare earths to concentrations 1.7-3.8 times those of HCl solutions of comparable pH, indicating that compounds exogenously released by these organisms contribute substantially to leaching. Organic acids released by the organisms included acetic, citric, gluconic, itaconic, oxalic, and succinic acids. Abiotic leaching with laboratory prepared solutions of these acids was not as effective as bioleaching or leaching with cell-free spent medium at releasing rare earths from monazite, indicating that compounds other than the identified organic acids contribute to leaching performance. © 2015 Wiley Periodicals, Inc.

  2. NMR study of electron spin density distribution in rare-earth intermetallic compounds with iron and cobalt

    International Nuclear Information System (INIS)

    Vasil'kovskij, V.A.; Gorlenko, A.A.; Kupriyanov, A.K.; Ostrovskij, V.F.

    1988-01-01

    It is shown that in intermettalic compounds local fields in rare earth (RE) element nuclei directed by 3d-sublattice atoms depend on 3d-atom type but they practically do not depend on the value of its magnetic moment and the compound stoichiometry. The results are explained in the assumption concerning the presence of a system of collectivized electrons, their spin polarization determining the field in RE nuclei and contributing to 3d-atom magnetic moment

  3. An approximate method for calculating the deformation of rotating nuclei

    International Nuclear Information System (INIS)

    Lind, P.

    1988-01-01

    The author presents as a collective model where the potential surface at spin I=0 is calculated in the Nilsson-Strutinsky model, an analytical expression for the moment of inertia is used which depends on the deformation and the pairing gaps for protons and neutrons, and the energy is minimized with respect to these gaps. Calculations in this model are performed for 16 Oyb. (HSI)

  4. Raw materials for advanced ceramics: rare earths separation processes

    International Nuclear Information System (INIS)

    Ricci, D.R.; Nobre, J.S.M.; Paschoal, J.O.A.

    1990-01-01

    The importance of obtaining purified rare earths oxidesis related, mainly to the increasing use of these compounds as raw materials for advanced ceramics. Processes of rare earths separation and purification are almost always based on the solvent extraction, fractional precipitation and ion exchange chromatography techniques, whose association depends on the initial concentrate and on the desired purity. This paper describes some steps of fractionation of didymium carbonate by using the solvent extraction and fractional precipitation techniques. The experimental conditions presented here have enable the production of lantanium, neodimium - praseodimium, samarium - gadolinium and ytrium concentrates, which constitute the intermediate fractions of the overall process to obtain high purity rare earths. (author) [pt

  5. Forced-flow chromatography of rare earths using sensitive spectrophometry

    International Nuclear Information System (INIS)

    Matsui, Masakazu; Aoki, Toru; Kumagai, Tetsu.

    1981-01-01

    The sensitive spectrophotometric method for the rare earth elements with xylenol orange in the presence of cetylpyridinium bromide was applied to the continuous detection system of liquid chromatography. Fourteen rare earth elements were completely separated within 130 min cation-exchange chromatography using 2-hydroxy-iso-butylic acid. The eluted ions were determined with absorption maxima of their complexes at around 610 nm. A linear relationship between the peak height and the amounts of rare earth elements was also obtained over the range 0.04 to 0.5 MU g. (author)

  6. Thermal Oxidation Resistance of Rare Earth-Containing Composite Elastomer

    Institute of Scientific and Technical Information of China (English)

    邱关明; 张明; 周兰香; 中北里志; 井上真一; 冈本弘

    2001-01-01

    The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found that its retention rate of mechanical properties is far higher than that of the control sample. The results of thermogravimetric analysis show that its thermal-decomposing temperature rises largely. The analysis of oxidation mechanisms indicates that the main reasons for thermal oxidation resistance are that rare earth elements are of the utility to discontinue autoxidation chain reaction and that the formed complex structure has steric hindrance effect on oxidation.

  7. Thermochemistry of certain rare earth and ammonium double chlorides

    International Nuclear Information System (INIS)

    Usubaliev, D.U.; Abramtsev, V.A.; Kydynov, M.K.; Vilyaev, A.N.

    1987-01-01

    In a calorimeter with isothermal casing at 25 deg C dissolution enthalpies of double chlorides of rare earths and ammonium LnCl 3 x2NH 4 Cl (Ln=La, Sm) and LnCl 3 x3NH 4 Cl (Ln=Gd, Tb, Ho) in water, as well as dissolution enthalpy of rare earth chlorides in solution of ammonium chloride and NH 4 Cl in solution of rare earth chloride, have been measured. Formation enthalpies, standard formation enthalpies, dissociation enthalpies of the above-mentioned double chlorides are calculated

  8. Membrane assisted solvent extraction for rare earth element recovery

    Science.gov (United States)

    Bhave, Ramesh R.; Kim, Daejin; Peterson, Eric S.

    2018-05-15

    Systems and methods for the recovery of rare earth elements are provided. The systems and methods generally include membrane assisted solvent extraction using permeable hollow fibers having an immobilized organic phase within the pores of the hollow fibers. The permeable hollow fibers are generally in contact with an acidic aqueous feed on one side thereof and a strip solution on another side thereof. The systems and methods generally include the simultaneous extraction and stripping of rare earth elements as a continuous recovery process that is well suited for post-consumer products, end-of-life products, and other recovery sources of rare earth elements.

  9. Heavy ion interactions of deformed nuclei. Progress report, May 1, 1984-December 31, 1984

    International Nuclear Information System (INIS)

    Oberacker, V.E.

    1984-11-01

    This progress report describes the main topics that were investigated during the reporting period: (a) a new microscopic approach to the calculation of heavy ion interaction potentials; (b) the dynamical orientation of deformed heavy nuclei near the distance of closest approach; and (c) the theory of Coulomb fission (project finished in Sept.)

  10. g-factors in deformed nuclei: Annual report, September 1, 1983-August 31, 1984

    International Nuclear Information System (INIS)

    Krane, K.S.

    1984-01-01

    This report describes work performed for the period September 1, 1983 to August 31, 1984 under the contract DE-AT06-83ER40109, /open quotes/g-Factors in Deformed Nuclei./close quotes/ The literature survey has been completed and the first stage of the raw data analysis has been accomplished. A preliminary data summary prepared for publication is attached

  11. Pauli principle role in the description of collective non-rotational states of deformed nuclei

    International Nuclear Information System (INIS)

    Solov'ev, V.G.; Shirikova, N.Yu.; Serdyukova, S.I.; Meliev, F.; Nesterenko, V.O.

    1981-01-01

    The Pauli principle role account for one-phonon and two- phonon states of even-even deformed nuclei sup(160, 164)Dy, sup(230, 232)Th, 154 Gd, 240 Pu, 238 U is performed. With account of isoscalar part of multipole-multipole interaction hamiltonian of a model and basic equations for energy and wave functions of one-phonon and two-phonon states are obtained. The results of calculations of centroids of energies of two-phonon states of the (lambda 1 μ 1 i 1 lambda 2 μ 2 i 2 ) type with and without the Pauli principle are tabulated. The calculations performed have shown that the energy centroids shift of collective two-phonon states with the Pauli-principle account is characteristic for all even-even deformed nuclei. In the authors opinion additional experimental investigations of 154 Cd, 164 Dy, 240 Pu two-phonon nuclei states to confirm theoretical results are necessary [ru

  12. Mass coefficient systematics in triaxially deformed Xe and Ba nuclei

    International Nuclear Information System (INIS)

    Singh, Yuvraj; Bihari, Chhail; Singh, M.; Varshney, A.K.; Gupta, K.K.; Gupta, D.K.

    2009-01-01

    In A ∼ 120-140 region where transition occurs from vibrator like stretching around the neutron closed shell (N = 82) to a region with more rotational character (N = 66) energies and B(E2) values of the low lying states change slowly and smoothly with N and Z indicating the collective nature of the levels. The systematic investigation of such nuclei within an isotopic chain undergoing shape or phase transitions is of particular current interest in nuclear structure physics. Rotation is one of the specific collective motions in finite body systems. When the angular momentum increase, one can observe how the energies of the quantum state change due to the effect of the coriolis and centrifugal forces. Thus in the transition to excited states the axial symmetry of the nucleus is violated even if it existed in the ground state

  13. Exotic octupole deformation in proton-rich Z=N nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Satoshi; Yabana, K [Niigata Univ. (Japan); Matsuo, M

    1998-03-01

    We study static non-axial octupole deformations in proton-rich Z=N nuclei, {sup 64}Ge, {sup 68}Se, {sup 72}Kr, {sup 76}Sr, {sup 80}Zr and {sup 84}Mo, by using the Skyrme Hartree-Fock plus BCS method with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in {sup 68}Se is extremely soft for the Y{sub 33} triangular deformation, and that in {sup 80}Zr the low-lying local minimum state coexisting with the prolate ground state has the Y{sub 32} tetrahedral deformation. (author)

  14. Research On Technology Of Making Rare Earth Alloy Having Rare Earth Content ≽30% From Ore (≽40% REO) Using Aluminum Thermal Technology In Arc Furnace

    International Nuclear Information System (INIS)

    Ngo Xuan Hung; Ngo Trong Hiep; Tran Duy Hai; Nguyen Huu Phuc

    2014-01-01

    Arc furnace was used to smelt materials consisting of rare earth ore having rare earth content of ≽40% REO, aluminum as the reducing agent and additives. Rare earth alloy was obtained with rare earth metal content of more than 30%. (author)

  15. Compact Rare Earth Emitter Hollow Cathode

    Science.gov (United States)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  16. On connection of rotation and internal motion in deformed nuclei

    International Nuclear Information System (INIS)

    Krutov, V.A.

    1979-01-01

    In the semiphenomenological nuclear madel (SPNM) the problem of ''overestimate of Coriolis interaction'' is shown to be easily solved. The rotation and internal motion coupling operator H(rot/in) is used. Overdetermination of the operator H(rot/in) has been generalized and extended into schemes of strong and weak coupling. In this case both schemes of coupling are transformed from approximate into precise ones and become applicable for any nuclear deformation. As examples of application of the theory considered are the matrix elements of the E2-transitions and inertia parameters of a 235 U nucleus

  17. Multilayer Thermal Barrier Coating (TBC) Architectures Utilizing Rare Earth Doped YSZ and Rare Earth Pyrochlores

    Science.gov (United States)

    Schmitt, Michael P.; Rai, Amarendra K.; Bhattacharya, Rabi; Zhu, Dongming; Wolfe, Douglas E.

    2014-01-01

    To allow for increased gas turbine efficiencies, new insulating thermal barrier coatings (TBCs) must be developed to protect the underlying metallic components from higher operating temperatures. This work focused on using rare earth doped (Yb and Gd) yttria stabilized zirconia (t' Low-k) and Gd2Zr2O7 pyrochlores (GZO) combined with novel nanolayered and thick layered microstructures to enable operation beyond the 1200 C stability limit of current 7 wt% yttria stabilized zirconia (7YSZ) coatings. It was observed that the layered system can reduce the thermal conductivity by approximately 45 percent with respect to YSZ after 20 hr of testing at 1316 C. The erosion rate of GZO is shown to be an order to magnitude higher than YSZ and t' Low-k, but this can be reduced by almost 57 percent when utilizing a nanolayered structure. Lastly, the thermal instability of the layered system is investigated and thought is given to optimization of layer thickness.

  18. Study on lowering the specific radioactivity of rare earth chlorides

    International Nuclear Information System (INIS)

    Shinhuor, Y.; Jyuung, J.; Shyuerjung, T.; Xiangping, L.

    1985-01-01

    In this paper, the source of radioactivity in rare earth chlorides and the chemical behaviour of its main radionuclides in metallurgy processing are investigated. It is pointed out that the radioactivity in rare earths comes from the long-life radionuclides in three natural radioactive series. Nine of them (/sup 238/U, /sup 234/U, /sup 230/Th, /sup 226/Ra, /sup 210/Po, /sup 232/Th, /sup 228/Th, /sup 235/U, /sup 231/Pa) are alpha-emitters, three of them (/sup 228/Ra, /sup 227/Ac, /sup 210/Pb) are beta-emitters. Among them alpha-emitters contribute the total specific activity of rare earths directly. The rare earths are easily purified in preferential dissolution, radium elimination, and other processes

  19. Separation of heavier rare earths from neutron irradiated uranium targets

    International Nuclear Information System (INIS)

    Bhargava, V.K.; Rao, V.K.; Marathe, S.G.; Sahakundu, S.M.; Iyer, R.H.

    1978-01-01

    A radiochemical method is described for the separation of heavier rare earths from the fission of uranium. The method is particularly suitable for the separation of low yield (10sup(-5)%-10sup(-7)%), highly asymmetric rare earth fission products viz. sup(179,177)Lu, sup(175)Yb, sup(173)Tm, sup(172,171)Er, sup(167)Ho and sup(161,160)Tb in the neutron induced fission of natural and depleted uranium targets. Additional separation steps have been incorporated for decontamination from sup(239)Np (an activation product) and sup(93-90)Y (a high fission-yield product) which show similar chemical behaviour to rare earths. Separation of individual rare earths is achieved by a cation exchange method performed at 80 deg C by elution with α-hydroxyisobutyric acid (α-HIBA). (author)

  20. Separation of rare earths by liquid-liquid extraction

    International Nuclear Information System (INIS)

    Helgorsky, M.; Leveque, M.

    1978-01-01

    The elements of the rare earth family are characterised by very similar chemical properties connected with their special electronic structure. The purification of the rare earths sold by RHONE-POULENC is now done by the liquid-liquid extraction technique. The development of different extracting agents and also counter-current techniques have led to solvent extraction replacing the other fractionation techniques because of its efficiency and low cost. There are usually several possible solutions to the main problem of choosing the extracting agent and its mode of use. The difficulty is to find the most economical one taking account of the thermodynamic and hydrodynamic constraints of the solvent. It is shown how ideas about the separation have changed over the course of the development of the uses of the rare earths, ending finally in an integrated scheme that makes RHONE-POULENC a world leader of manufacturers of separated rare earths [fr

  1. Exploitation of rare earth catalysts in polymer syntheses

    Institute of Scientific and Technical Information of China (English)

    Shen Zhiquan

    2006-01-01

    The studies over forty years on rare earth catalysts in polymer syntheses of diene,alkyne,alkylene oxide,thiirane, carbon dioxide copolymerization, lactide,caprolactone,cyclic carbonate and so forth in China have been reviewed.

  2. Prospects for trivalent rare earth molecular vapor lasers for fusion

    International Nuclear Information System (INIS)

    Krupke, W.F.

    1976-01-01

    The dynamical properties of three types of RE 3+ molecular vapors were considered: (1) rare earth trihalogens, (2) rare earth trihalogens complexed with transition metal trihalogens, and (3) rare earth chelates. Radiative and nonradiative (unimolecular and bimolecular) transition probabilities have been calculated using phenomenological models predicted on the unique electronic structure of the triply ionized RE ion (well shielded ground electronic configuration of equivalent of electrons). Although all the lanthanide ions have been treated in some detail, specific results are presented for the Nd 3+ and Tb 3+ ions to illustrate the systematics of these vapors as a class of new laser media. Once verified, these phenomenological models will provide a powerful tool for the directed experimental exploration of these systems. Because of the structural similarity to the triply ionized actinides, comments offered here for the lanthanide rare earth series generally apply to gaseous actinide lasers which are also under consideration

  3. Rare earths: Market disruption, innovation, and global supply chains

    Science.gov (United States)

    Eggert, Roderick; Wadia, Cyrus; Anderson, Corby; Bauer, Diana; Fields, Fletcher; Meinert, Lawrence D.; Taylor, Patrick

    2016-01-01

    Rare earths, sometimes called the vitamins of modern materials, captured public attention when their prices increased more than ten-fold in 2010 and 2011. As prices fell between 2011 and 2016, rare earths receded from public view—but less visibly they became a major focus of innovative activity in companies, government laboratories and universities. Geoscientists worked to better understand the resource base and improve our knowledge about mineral deposits that will be mines in the future. Process engineers carried out research that is making primary production and recycling more efficient. Materials scientists and engineers searched for substitutes that will require fewer or no rare earths while providing properties comparable or superior to those of existing materials. As a result, even though global supply chains are not significantly different now than they were before the market disruption, the innovative activity motivated by the disruption likely will have far-reaching, if unpredictable, consequences for supply chains of rare earths in the future.

  4. Corrosion resistance of chromium-nickel steel containing rare earths

    International Nuclear Information System (INIS)

    Asatiani, G.N.; Mandzhgaladze, S.N.; Tavadze, L.F.; Chuvatina, S.N.; Saginadze, D.I.

    1983-01-01

    Effect of additional out-of-furnace treatment with complex alloy (foundry alloy) calcite-silicon-magnesium-rare earth metal on corrosion resistance of the 03Kh18N20M3D3C3B steel has been studied. It is shown that introduction of low additions of rare earths improves its corrosion resistance improves its corrosion resistance in agressive media (in 70% - sulfuric acid) in the range of transition from active to passive state. Effect of additional introduction of rare earth metals is not considerable, if potential of steel corrosion is in the range of stable passive state (32% - sulfuric acid). Additional out-of-furnace treatment with complex foundry alloy, containing rare earth metals, provides a possibility to use a steel with a lower content of Cr, Ni, Mo, than in conventional acid-resistant steels in highly agressive media

  5. Flotation process of lead-, copper-, uranium-, and rare earth minerals

    International Nuclear Information System (INIS)

    Broman, P.G.; Kihlstedt, P.G.; Du Rietz, C.

    1977-01-01

    This invention relates to a flotation process of oxide or sulfide ores containing lead-, copper-, uranium-, and rare earth minerals applicating a new collector. Flotation is in the presence of a tertiary amine

  6. Science and technology of the rare earth elements

    International Nuclear Information System (INIS)

    Azzouz, Abdelkrim; Chegrouche, Salah; Telmoune, Sid-Ali; Layachi, Lazhar

    1992-07-01

    The present work studies the chemical physics properties, the different methods of analysis (neutron activation, emission spectrometry, chromatography), and the techniques of separation of rare earth (electrodeposition, thermic decomposition, salts distillation and ions exchange)

  7. Isomerization of butene-1 on rare earth oxides. [Rare earths: La, Nd, Dy

    Energy Technology Data Exchange (ETDEWEB)

    Khodakov, Yu S; Nesterov, V K; Minachev, Kh M [AN SSSR, Moscow. Inst. Organicheskoj Khimii

    1975-09-01

    A study has been made into the isomerization of butene-1 on oxides of rare-earth elements. The dependence of the reaction rate at 20/sup 0/C on the baking temperature of La and Nd oxides have the maximum at 700/sup 0/C. A decrease in the activity of these oxides after bakinq at 800/sup 0/C is observed, as well as during experiments at -30 deq C. In the case of Dy/sub 2/O/sub 3/, the activity at 20/sup 0/C increases gradually with Tsub(bak)=500 to 800/sup 0/C Zeolite 0.57LaNaY exhibits maximum activity at Tsub(bak)=500/sup 0/C Similar data as to the effect of the baking temperature on the catalyst activity were obtained earlier for hydrogenation of ethylene. According to their maximum activity, oxides of rare-earth elements, in the isomerization as well as hydrogenation reactions, can be arranged as follows: La/sub 2/O/sub 3/>Nd/sub 2/O/sub 3/

  8. Magnetism in rare-earth metals and rare-earth intermetallic compounds

    International Nuclear Information System (INIS)

    Johansson, B.; Nordstroem, L.; Eriksson, O.; Brooks, M.S.S.

    1991-01-01

    Some of out recent local spin density electronic structure calculations for a number of ferromagnetic rare-earth systems are reviewed. A simplified model of the level densities for rare-earth (R) transition metal (M) intermetallic compounds, R m M n , is used to describe in a simple way the main features of their basic electronic structure. Explicit calculations for LuFe 2 and RFe 2 (R=Gd-Yb) systems are presented, where a method to treat simultaneously the localized 4f and the conduction electron spin magnetism is introduced. Thereby it becomes possible to calculate the K RM exchange coupling constant. This method is also used to study theoretically the permanent magnet material Nd 2 Fe 14 B. The electronic structure of the anomalous ferromagnets CeFe 2 and CeCo 5 is discussed and an induced 4f itinerant magnetism is predicted. The γ-α transition in cerium metal is considered, and results from calculations including orbital polarization are presented, where a volume collapse of 10% is obtained. On one side of the transition the 4f electrons are calculated to be essentially non-bonding (localized) and on the other side they are found to contribute to the metallic bonding and this difference in behaviour gives rise to the volume collapse. Recent calculations by Wills, Eriksson and Boring for the crystal structure changes in cerium metal under high pressure are discussed. Their successful results imply an itinerant picture for the 4f electrons in α-cerium. Consequently this strongly supports the view that the γ-α phase transformation is caused by a Mott transition of the 4f electrons. (orig.)

  9. Vibrational states in deformed nuclei. Chaos, order and individual nature of nuclei

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1993-01-01

    General properties of the vibrational states in doubly-even well-deformed are formulated. The large many-quasiparticle components of the wave functions of the neutron resonance state are responsible for enhance E1- and M1-transitions rates from the neutron resonances states to the levels lying 1-2 MeV below them. 44 refs.; 4 tabs

  10. Results and simulations on γ-spectroscopy of deformed nuclei: cases of isomers and tetrahedral nuclei

    International Nuclear Information System (INIS)

    Vancraeyenest, A.

    2010-10-01

    The major part of this work is about the realization and complete analysis of an experiment for studying isomeric states in 138,139,140 Nd nuclei. This was performed at Jyvaeskylae laboratory (Finland) using a fusion-evaporation reaction with 48 Ca beam on a thin 96 Zr target. Experimental setup consisted in the target position gamma ray detector Jurogam II which was coupled with the RITU recoil separator and the GREAT focal plane detector array. This particularly well adapted setup permit to manage γ spectroscopy of the interest nuclei around isomeric states. Indeed, we used prompt-delayed matrices to separate rays that come onto isomeric states and these who decay from them. Then, the correlations between the two components permit to establish feeding transitions of isomeric states. Thanks to this experiment, a new isomeric state was also highlighted in 139 Nd with spin 23/2+, which was predicted and interpreted in Cranked-Nilsson-Strutinsky calculation. Finally, very clean time spectra allow to determine precisely life-time of four states in four nuclei. This Ph.d. is also made of a part of the analysis of the first experimental search for fingerprints of tetrahedral symmetry in 156 Gd using high fold gamma ray spectroscopy. Thanks to a large number of triple coincidence events, we managed a detailed spectroscopy of this nucleus. Particularly, we found out 13 new transitions in positive parity bands. As a complement of this work, we have done GEANT4 simulations about the detection limits of low intensity transitions by Agata multidetector. Indeed, tetrahedral symmetry predicts vanishing of E2 transitions at lower spin states and simulations permit to determine observation limit of these transitions with different version of Agata. (author)

  11. Mother Lode: The Untapped Rare Earth Mineral Resources of Vietnam

    Science.gov (United States)

    2013-11-01

    to exert their monopolistic control of the market by artificially restricting supply in the interest of higher commodity prices, but were rather...linked. World markets for rare earth elements are at present a near-monopoly controlled by China, and it is becoming ever clearer that alternative... markets for rare earth elements are at present a near- monopoly controlled by China, and it is becoming ever clearer that alternative sources for these

  12. Rare-earth elements in granites: concentration and distribution pattern

    International Nuclear Information System (INIS)

    Galindo, A.C.

    1983-01-01

    The geochemistry of rare earth elements in granites is studied. The rare earth element (REE) distribution pattern in granites is characterized by a smooth curve with decreasing concentrations from La to Lu, and frequently a marked Eu negative anomaly. It seems to exist relationship between granite genesis and its REE pattern, in that bodies of primary (magmatic differentiation) origin always show this negative Eu anomaly, while those bodies generated by crustal anatexis do not show this anomaly. (E.G.) [pt

  13. Synthesis and physicochemical investigation of adducts of rare earth thenoyltrifluoroacetonates

    International Nuclear Information System (INIS)

    Anufrieva, S.I.; Snezhko, N.I.; Martynenko, L.I.; Pechurova, N.I.

    1982-01-01

    Adducts of rare earth thenoyltrifluoroacetonates (3) have been synthesized with tributylphosphate (TBP), trioctylphosphenoxide (TOPO), triphenylphosphenoxide (TPO) of 1:1 and 1:2 composition as well as with α, α'-dipyridine (Dipy), o-phenanthroline (Phen) of 1:1 composition. The separated adducts have been studied by methods of element analysis, X-ray phase and derivatographic analyses and IR spectroscopy. It is shown that the adducts are more thermostable compared to the corresponding rare earth thenoyltrifluoroacetonate hydrates

  14. Resistivity and magnetoresistivity of amorphous rare-earth alloys

    Science.gov (United States)

    Borchi, E.; Poli, M.; De Gennaro, S.

    1982-05-01

    The resistivity and magnetoresistivity of amorphous rare-earth alloys are studied starting from the general approach of Van Peski-Tinbergen and Dekker. The random axial crystal-field and the magnetic correlations between the rare-earth ions are consistently taken into account. The characteristic features of the available experimental data are explained both of the case of random ferromagnetic and antiferromagnetic order.

  15. Chromates (3) and chromates (5) of rare earths

    International Nuclear Information System (INIS)

    Suponitskij, Yu.L.

    1986-01-01

    Data on preparation methods, structure and properties of chromates (3, 5) and mixed chromates (3) of rare earths, scandium and yttrium are generalized. Phase diagrams of systems Ln 2 O 3 -Cr 2 O 3 (Ln - rare earths, Sc, Y), chemical and thermodynamic properties of chromates (3, 5), their crystal structure and character of thermal decomposition are considered. Application fields of the compounds mentioned are suggested

  16. Electronic structure and properties of rare earth and actinide intermetallics

    International Nuclear Information System (INIS)

    Kirchmayr, H.R.

    1984-01-01

    There are 188 contributions, experimental and theoretical, a few on rare earth and actinide elements but mostly on rare earth and actinide intermetallic compounds and alloys. The properties dealt with include 1) crystal structure, 2) magnetic properties and magnetic structure, 3) magnetic phase transformations and valence fluctuations, 4) electrical properties and superconductivity and their temperature, pressure and magnetic field dependence. A few papers deal with crystal growth and novel measuring methods. (G.Q.)

  17. Yttrium and rare earths separation by ion exchange resin

    International Nuclear Information System (INIS)

    Pinatti, D.G.; Ayres, M.J.G.; Ribeiro, S.; Silva, G.L.J.P.; Silva, M.L.C.P.; Martins, A.H.

    1988-01-01

    The experimental results of yttrium and rare earths separation from Brazilian xenotime are presented. The research consist in five stage: 1) Preparation of yttrium, erbium and lutetium standard solutions, from solubilization of pure oxides 2) yttrium and rare earths separation by ion exchange chromatrography 3) Separation and recovery of EDTA 4) Precipitation and calcination and 4) Analytical control of process. (C.G.C.) [pt

  18. Rare Earth-Activated Silica-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    C. Armellini

    2007-01-01

    Full Text Available Two different kinds of rare earth-activated glass-based nanocomposite photonic materials, which allow to tailor the spectroscopic properties of rare-earth ions: (i Er3+-activated SiO2-HfO2 waveguide glass ceramic, and (ii core-shell-like structures of Er3+-activated silica spheres obtained by a seed growth method, are presented.

  19. Preparing rare earth-silicon-iron-aluminum alloys

    International Nuclear Information System (INIS)

    Marchant, J.D.; Morrice, E.; Herve, B.P.; Wong, M.M.

    1980-01-01

    As part of its mission to assure the maximum recovery and use of the Nation's mineral resources, the Bureau of Mines, investigated an improved procedure for producing rare earth-silicon alloys. For example, a charge consisting of 681 grams of mixed rare-earth oxides, 309 grams of ferrosilicon (75 wt-pct Si), and 182 grams of aluminum metal along with a flux consisting of 681 grams of CaO and 45 grams of MgO was reacted at 1500 0 C in an induction furnace. Good slag-metal separation was achieved. The alloy product contained, in weight-percent, 53 RE, 28 Si, 11 Fe, and 4 Al with a rare earth recovery of 80 pct. In current industrial practice rare earth recoveries are usually about 60 pct in alloy products that contain approximately 30 wt-pct each of rare earths and silicon. Metallurgical evaluations showed the alloys prepared in this investigation to be as effective in controlling the detrimental effect of sulfur in steel and cast iron as the commercial rare earth-silicon-iron alloys presently used in the steel industry

  20. Handbook on the physics and chemistry of rare earths

    International Nuclear Information System (INIS)

    Gschneidner, K.A. Jr.; Eyring, L.

    1982-01-01

    This handbook is a six-volume work which covers the entire rare earth field in an integrated manner. Each chapter is a comprehensive, up-to-date, critical review of a particular segment of the field. The first volume is devoted to the rare earth metals, the second to rare earth alloys and intermetallics, and the third and fourth volumes to the non-metallic rare earth materials, including solutions, complexes and bioinorganic substances, in addition to solid inorganic compounds. The electronic structure of these unique elements is the primary basis of understanding their physical, metallurgical and chemical natures. The interrelationship of the 4f and valence electrons and the observed optical, electrical, magnetic, crystallographic, elastic, thermal, mechanical, chemical, geochemical and biological behaviors is brought forth time and again throughout the chapters. Also discussed are the preparative, separation and solution chemistry of the elements and their compounds and the various chemical and physical analytical methods for determining the rare earths in various materials and impurities in a rare earth matrix. Vol. 5 is a update complement of the previous volumes. Volume 6 is concerned with ternary and higher order materials. (Auth.)

  1. Determination of rare earths in their extraction processing

    International Nuclear Information System (INIS)

    You Jiannan; Zhang Yuqin

    1989-01-01

    A method for determination of rare earths in ores, ion-exchange resins and solution samples has been developed. The ore is molten with sodium peroxide and the molten sample is leached with triethenol amine and sodium citrate. In weak acid medium, the rare earths can be extracted by PMBP-phenol solution, and stripped with formic acid. In the acetic acidsodium acetate buffer medium of pH3, the spectrophotometric determination of rare earths with arsenazo M has been made. The rare earths in ion-exchange resins can be directly determined by spectrophotometry after being leached with hydrochloric acid and at heated condition. The rare earths with arsenazo M or a red complex. The maximum absorption of the complex is at 640 nm, and the molar absorption is 8.0 x 10 4 L centre dot mol -1 centre dot cm -1 . While the range of determination is 0.005%-0.5% and 0.001-1.0 g/L, the relative standard deviation is less than 5%, and recovery of rare earths is 98.5-105%. The method is rather simple and rapid

  2. Rare earth industries; Moving Malaysia's Green Economy Forward

    International Nuclear Information System (INIS)

    2011-08-01

    There is a famous saying, Where there is risk, there is opportunity. Rare earths present both health and environmental risks as well as potential economic opportunities. However, the risks are manageable thanks to improved technologies and a better understanding of the implications on health and the environment. This explains why there is a rush by many countries to reopen old mines and increase investment in the production of rare earths concentrate and their high value downstream products. Why is there such a scramble to risk money on rare earths? What have ignited global demand? Where are the opportunities? How are the risks associated with rare earths managed? Can Malaysia benefit from this new growth industry? What should be our strategies? This report, produced by the joint Working Group of the Academy of Sciences Malaysia (ASM) and the Majlis Professor Negara (MPN), discusses the science of rare earths and their business prospects; and proposes some strategic directions for Malaysia. The analysis is based on information culled from various secondary sources as well as the groups engagement with experts from the Rare Earths Society of China. (author)

  3. An Overview of Rare Earth Science and Technology

    Science.gov (United States)

    Gschneidner, Karl, Jr.

    2012-02-01

    Currently rare earth science and technology is robust: this includes all the major branches of science -- biochemistry, chemistry, materials and physics. There are, however, currently some anomalies and distortions especially in the technology and applications sector of the rare earth field, which is caused by the dominance of China on the sales of rare earths and rare earth containing products. For the past 5 to 10 years ˜95% of rare earths utilized in commerce came from China. Although Chinese actions have lead to sudden and large price spikes and export embargoes, the rare earths are still available but at a higher cost. The start up of production in 2011 at mines in the USA and Australia will alleviate this situation in about two years. Basic and applied research on the condensed matter physics/materials science has hardly been impacted by these events, but new research opportunities are opening up especially with regard to the USA's military and energy security. Magnets seems to be the hottest topic, but research on battery materials, phosphors and catalysts are also (or should be) strongly considered.

  4. Extraction studies on rare earths using dinonyl phenyl phosphoric acid

    International Nuclear Information System (INIS)

    Anitha, M.; Singh, D.K.; Kotekar, M.K.; Vijayalakshmi, R.; Singh, H.

    2011-01-01

    Rare earths are widely used in phosphor materials, magnetic substances, alloys, catalyst, lasers, superconductors, solid oxide fuel cells and in nuclear applications. The high value of these elements depends on their effective separation into high purity compounds. The separation into individual rare earths is very difficult to achieve, due to the very low separation factors between two adjacent rare earths arising due to similar chemical properties. Taking the advantage of variation in basicity, the separation is generally accomplished by solvent extraction or ion exchange. There are several references on the separation of rare earth in different media employing various types of extractants such as 2-ethylhexyl 2-ethyhexylphosphonic acid (EHEHPA) and di-2-ethyl hexyl phosphoric acid (D2EHPA) which have been widely used for the separation and purification of rare earths. Dinonyl phenyl phosphoric acid (DNPPA) is an organo phosphorus extractant (pKa = 2.54) and is an aromatic analogue of D2EHPA, which extracts metal ion by cation exchange mechanism. DNPPA was explored to recover rare earths from phosphate media such as wet process phosphoric acid and merchant grade acid. However, there is no information available in literature on DNPPA for RE extraction from chloride medium. Therefore, an attempt has been made in the present study to investigate the feasibility of using DNPPA for extraction of La(III), Dy(III) and Y(III) from chloride medium

  5. Deformed model Sp(4) model for studying pairing correlations in atomic nuclei

    CERN Document Server

    Georgieva, A I; Sviratcheva, K

    2002-01-01

    A fermion representation of the compact symplectic sp(4) algebra introduces a theoretical framework for describing pairing correlations in atomic nuclei. The important non-deformed and deformed subalgebras of sp sub ( sub q sub ) (4) and the corresponding reduction chains are explored for the multiple orbit problem. One realization of the u sub ( sub q sub ) (2) subalgebra is associated with the valence isospin, other reductions describe coupling between identical nucleons or proton-neutron pairs. Microscopic non-deformed and deformed Hamiltonians are expressed in terms of the generators of the sp(4) and sp sub q (4) algebras. In both cases eigenvalues of the isospin breaking Hamiltonian are fit to experimental ground state energies. The theory can be used to investigate the origin of the deformation and predict binding energies of nuclei in proton-rich regions. The q-deformation parameter changes the pairing strength and in so doing introduces a non-linear coupling into the collective degree of freedom

  6. Influence of fragment deformation and orientation on compact configuration of odd-Z superheavy nuclei

    International Nuclear Information System (INIS)

    Gurjit Kaur; Sandhu, Kirandeep; Sharma, Manoj K.

    2016-01-01

    The synthesis of heavy and superheavy nuclei is generally carried out by using hot and cold fusion reaction mechanisms. It has been noticed that, the cold fusion reactions occur at relatively low excitation energies (E*_C_N ∼ 10-20 MeV) whereas, the hot fusion reactions occur at excitation energies of E*_C_N ∼ 30- 50 MeV. The fusion mechanism is quite different in both the processes. In the cold fusion process, the interaction of spherical targets (Pb and Bi) with deformed light mass projectiles occurs. On the other hand, the fusion of deformed actinide targets with spherical "4"8Ca projectile characterize the hot interaction processes. Hence the deformations and orientations of targets and projectiles play extremely important role in the superheavy fusion process. The present analysis is carried out to aggrandize the work of which illustrate the role of deformations and orientations on even superheavy nuclei. Here, we extend this analysis for odd superheavy nuclei. It is relevant to note that the temperature and angular momentum effects are not included in the present analysis

  7. Precipitation of the rare earth double sodium and rare earths from the sulfuric liquor and the conversion into rare earth hydroxides through meta ethic reaction

    International Nuclear Information System (INIS)

    Abreu, Renata D.; Oliveira, Ester F.; Brito, Walter de; Morais, Carlos A.

    2007-01-01

    This work presents the purification study of the rare earths through precipitation of rare earth and sodium (Na TR (SO 4 ) 2 . x H 2 O)) double sulfate and his conversion to rare earths hydroxide TR(OH) 3 by meta ethic reaction through the addition of sodium hydroxide solution to the solid double sulfate. The study used the sulfuric liquor as rare earth sample, generated in the chemical processing of the monazite with sulfuric acid by the Industrias Nucleares do Brasil - INB, Brazil, after the thorium and uranium extraction. The work investigated the influence of the main variables involved in the precipitation of Na TR(SO 4 ) 2 .xH 2 O and in the conversion for the TR(OH) 3 , as follows: type and excess of the precipitation agent, temperature and time reaction. The obtained solid composites were characterized by X-ray diffraction, infrared and chemical analysis. The double sulfate diffractogram indicated the Na TR(SO 4 ) 2 mono-hydrated. The characterization of the metatese products has shown that, for obtaining the complete conversion of NaTR(SO 4 ) 2 .H 2 O into TR(OH) 3 , the reaction must be hot processed (∼70 deg C) and with small excess of Na OH (≤ 5 percent). (author)

  8. Thermodynamics and kinetics of the formation of rare earth intermetallics

    International Nuclear Information System (INIS)

    Deodhar, S.S.

    1975-01-01

    Heats of reaction of rare earth intermetallics with iron, cobalt and nickel were determined using Differential Thermal Analysis technique. The intermetallic compounds studied were of MgCu 2 type Laves phases and the rare earth elements studied were praseodymium, gadolinium, dyprosium and erbium. The reactions were exothermic and the heats of reaction were generally high. They varied from the low of -2.5 kcal/g mole for Fe 2 Gd to the high of -35.3 kcal/g mole for Ni 2 Er. The magnitudes of heats of reaction were always greater for the intermetallics of heavy rare earth elements. The rare earth intermetallics studied were either ferromagnetic or antiferromagnetic. The variations in the magnetic moments and the heats of reaction with respect to the atomic number of the rare earth elements followed certain trends. The similarities were observed in the trends of two properties. Electronic configuration for the MgCu 2 type rare earth intermetallics is proposed using Engel--Brewer correlation for metallic structures and the structural features of the Laves phase compounds. Kinetics of the reactions between the rare earth elements and iron, cobalt, and nickel was studied. The rate of reaction was diffusion controlled in each case. The Valensi--Carter equation for the diffusion mechanism satisfactorily described the kinetic behavior. The magnitudes of activation energies and frequency factors were determined. The reactions can be characterized by their reaction temperatures since they always begin at definite temperatures. It was observed that the reaction began at a higher temperature if the activation energy for the reaction was high

  9. Study of oblate nuclear shapes and shape coexistence in neutron-deficient rare earth isotopes

    CERN Multimedia

    Guttormsen, M S; Reiter, P; Larsen, A; Korten, W; Clement, E; Siem, S; Renstrom, T; Buerger, A; Jenkins, D G

    We propose to investigate nuclear shapes and shape coexistence in neutron-deficient rare earth nuclei below the N=82 shell closure at the ISOLDE facility by employing Coulomb excitation of Nd, Sm, Gd, and Dy beams from the REX accelerator and the Miniball experiment. Nuclear shapes are expected to change rapidly in this region of the nuclear chart. The measurement of electric quadrupole moments of excited states and the transition rates between them serves as a stringent test of theoretical models and effective nucleon-nucleon interactions.

  10. Process of diffractive scattering and disintegration of complex particles by nonspherical deformed nuclei

    International Nuclear Information System (INIS)

    Evlanov, M.V.

    1989-01-01

    The differential and integral cross sections of diffractive elastic and inelastic scattering and of the disintegration of complex particles by axial and nonaxial deformed nuclei are investigated depending on the shape, deformability and diffuseness of nuclear boundary as well as on the structure of the incident particles and of the rescattering processes. It is shown that the complicated coincidence experiments and experimnts on inelastic scattering with excitation of the target nucleus collective states are satisfactorily described taking simultaneously into account all factors mentioned above and the final-state interaction between the disintegration products of the incident particle

  11. Hartree-Fock calculations for strongly deformed and highly excited nuclei using the Skyrme force

    International Nuclear Information System (INIS)

    Zint, P.G.

    1975-01-01

    It has been shown that in CHF-calculations the Skyrme-force is usefull to describe strongly deformed nuclei with even proton and neutron number till separation. Thereby the eigenfunctions of the two-centre Hamiltonian form an adequate basis. With this procedure, we obtain the correct deformation of the 32 S-system. Induding the spurious energy of relative motion between the 16 O-fragments, the energy curve is a good approximation for the real potential, extracted form scattering experiments. (orig./WL) [de

  12. Improving the Calculation of The Potential Between Spherical and Deformed Nuclei

    International Nuclear Information System (INIS)

    Ismail, M.; Ramadan, Kh.A.

    2000-01-01

    The Heavy Ion (HI) interaction potential between spherical and deformed nuclei is improved by calculating its exchange part using finite range nucleon-nucleon (NN) force. We considered U 238 as a target nucleus and seven projectile nuclei to show the dependence of the HI potential on both the energy and orientation of the deformed target nucleus. The effect of finite range NN force has been found to produce significant changes in the HI potential. The variation of the barrier height V B , its thickness and its position R B due to the use of finite range NN force are significant. Such variation enhance the fusion cross-section at energy values just below the Coulomb barrier by a factor increasing with the mass number of projectile nucleus. (author)

  13. Effective field theory of emergent symmetry breaking in deformed atomic nuclei

    International Nuclear Information System (INIS)

    Papenbrock, T; Weidenmüller, H A

    2015-01-01

    Spontaneous symmetry breaking in non-relativistic quantum systems has previously been addressed in the framework of effective field theory. Low-lying excitations are constructed from Nambu–Goldstone modes using symmetry arguments only. We extend that approach to finite systems. The approach is very general. To be specific, however, we consider atomic nuclei with intrinsically deformed ground states. The emergent symmetry breaking in such systems requires the introduction of additional degrees of freedom on top of the Nambu–Goldstone modes. Symmetry arguments suffice to construct the low-lying states of the system. In deformed nuclei these are vibrational modes each of which serves as band head of a rotational band. (paper)

  14. Macroscopic-microscopic energy of rotating nuclei in the fusion-like deformation valley

    International Nuclear Information System (INIS)

    Gherghescu, R.A.; Royer, Guy

    2000-01-01

    The energy of rotating nuclei in the fusion-like deformation valley has been determined within a liquid drop model including the proximity energy, the two-center shell model and the Strutinsky method. The potential barriers of the 84 Zr, 132 Ce, 152 Dy and 192 Hg nuclei have been determined. A first minimum having a microscopic origin and lodging the normally deformed states disappears with increasing angular momenta. The microscopic and macroscopic energies contribute to generate a second minimum where superdeformed states may survive. It becomes progressively the lowest one at intermediate spins. At higher angular momenta, the minimum moves towards the foot of the external fission barrier leading to hyperdeformed quasi-molecular states. (author)

  15. Rare earth ion controlled crystallization of mica glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Garai, Mrinmoy; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in

    2016-09-05

    In understanding the effects of rare earth ions to control the crystallization and microstructure of alkaline boroaluminosilicate system, the CeO{sub 2}, Nd{sub 2}O{sub 3}, Sm{sub 2}O{sub 3} and Gd{sub 2}O{sub 3} doped K{sub 2}O−MgO−B{sub 2}O{sub 3}−Al{sub 2}O{sub 3}−SiO{sub 2}−F glasses were synthesized by melt-quenching at 1550 °C. Higher density (2.82–3.06 g cm{sup −3}) and thermal stability (glass phase) is experiential on addition of rare earth content, which also affects in increasing the glass transition temperature (T{sub g}) and crystallization temperature (T{sub c}). Decrease of thermal expansion in glasses with rare earth ion content is maintained by the stabilization of glass matrix owing to their large cationic field strength. A significant change in the non-isothermal DSC thermogram observed at 750–1050 °C is attributed to fluorophlogopite crystallization. Opaque glass-ceramics were prepared from such glasses by single step heat-treatment at 1050 °C; and the predominant crystalline phases are identified as fluorophlogopite mica, KMg{sub 3}(AlSi{sub 3}O{sub 10})F{sub 2} by XRD and EDX analysis. The compact glass-ceramic microstructure by the agglomeration of fluorophlogopite mica crystallites (crystal size ∼ 100–500 nm, FESEM) is achieved in attendance of rare earth ion; and such microstructure controlled the variation of density, thermal expansion and microhardness value. Higher thermal expansion (11.11–14.08 × 10{sup −6}/K at 50–800 °C and 50–900 °C) of such glass-ceramics approve that these rare earth containing glasses can be useful for high temperature vacuum sealing application with metal or solid electrolyte. The increase of Vickers microhardness (5.27–5.61 GPa) in attendance of rare earth ions is attributed to the compact crystallinity of fluorophlogopite mica glass-ceramic microstructure. - Highlights: • Synthesis of rare earth oxide doped alkaline boroaluminosilicate glasses. • Development of opaque

  16. Rare earth ion controlled crystallization of mica glass-ceramics

    International Nuclear Information System (INIS)

    Garai, Mrinmoy; Karmakar, Basudeb

    2016-01-01

    In understanding the effects of rare earth ions to control the crystallization and microstructure of alkaline boroaluminosilicate system, the CeO_2, Nd_2O_3, Sm_2O_3 and Gd_2O_3 doped K_2O−MgO−B_2O_3−Al_2O_3−SiO_2−F glasses were synthesized by melt-quenching at 1550 °C. Higher density (2.82–3.06 g cm"−"3) and thermal stability (glass phase) is experiential on addition of rare earth content, which also affects in increasing the glass transition temperature (T_g) and crystallization temperature (T_c). Decrease of thermal expansion in glasses with rare earth ion content is maintained by the stabilization of glass matrix owing to their large cationic field strength. A significant change in the non-isothermal DSC thermogram observed at 750–1050 °C is attributed to fluorophlogopite crystallization. Opaque glass-ceramics were prepared from such glasses by single step heat-treatment at 1050 °C; and the predominant crystalline phases are identified as fluorophlogopite mica, KMg_3(AlSi_3O_1_0)F_2 by XRD and EDX analysis. The compact glass-ceramic microstructure by the agglomeration of fluorophlogopite mica crystallites (crystal size ∼ 100–500 nm, FESEM) is achieved in attendance of rare earth ion; and such microstructure controlled the variation of density, thermal expansion and microhardness value. Higher thermal expansion (11.11–14.08 × 10"−"6/K at 50–800 °C and 50–900 °C) of such glass-ceramics approve that these rare earth containing glasses can be useful for high temperature vacuum sealing application with metal or solid electrolyte. The increase of Vickers microhardness (5.27–5.61 GPa) in attendance of rare earth ions is attributed to the compact crystallinity of fluorophlogopite mica glass-ceramic microstructure. - Highlights: • Synthesis of rare earth oxide doped alkaline boroaluminosilicate glasses. • Development of opaque fluorophlogopite mica glass-ceramics by single-step heat treatment. • Nanocrystalline glass

  17. Neutron activation analysis of rare earths in uranium containing rocks

    International Nuclear Information System (INIS)

    May, S.; Pinte, G.

    1984-01-01

    The determination of rare earths by activation analysis in uranium rocks is disturbed either by fission-produced rare earths, or by neptunium-239 originating from uranium-238. In order to eliminate these interferencies, the chemical separation of rare earths from uranium prior to activation should be performed. The chemical process is as follows: the rock sample is fused with sodium borate, then, after addition of hydrochloric acid, the resulting solution is passed through a Dowex 1x8 column. Uranium is retained on the resin, and rare earths and scandium are eluted. Aluminium is added as a carrier to the solution, and rare earths and scandium are coprecipitated with aluminium hydroxide. This precipitate is irradiated in the nuclear reactor. Gamma spectrometry is used for the determination of earth radionuclide. Activity measurements are performed in successive steps during one month. The following elements are determined: Pr, La, Sm, Nd, Yb, Lu, Ce, Tb, Eu and Sc. The chemical yield is measured by using scandium as an internal standard. (author)

  18. Squeezing clathrate cages to host trivalent rare-earth guests

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jian [Iowa State Univ., Ames, IA (United States). Department of Chemistry; Ames Lab., Ames, IA (United States); He, Yuping [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Mordvinova, Natalia E. [Laboratoire CRISMAT, ENSICAEN, CNRS UMR (France); Lebedev, Oleg [Laboratoire CRISMAT, ENSICAEN, CNRS UMR (France); Kovnir, Kirill [Iowa State Univ., Ames, IA (United States). Department of Chemistry; Ames Lab., Ames, IA (United States)

    2017-11-01

    Strike difference of the trivalent rare-earth cations from their alkali and alkaline-earth peers is in the presence of localized 4f-electrons and strong spin-orbit coupling. Placing trivalent rare-earth cations inside the fullerene molecules or in between the blocks of itinerant magnetic intermetallics gave rise to plethora of fascinating properties and materials. A long-time missing but hardly desired piece is the semiconducting or metallic compound where rare-earth cations are situated inside the oversized polyhedral cages of three-dimensional framework. In this work we present a synthesis of such compounds, rare-earth containing clathrates Ba8-xRxCu16P30. The unambiguous proofs of their composition and crystal structure were achieved by a combination of synchrotron powder diffraction, time-of-flight neutron powder diffraction, scanning-transmission electron microscopy, and electron energy-loss spectroscopy. Our quantum-mechanical calculations and experimental characterizations show that the incorporation of the rare-earth cations significantly enhances the hole mobility and concentration which results in the drastic increase in the thermoelectric performance.

  19. Spectrographic determination of some rare earths in thorium compounds

    International Nuclear Information System (INIS)

    Brito, J. de.

    1977-01-01

    A method for spectrographic determination of Gd, Sm, Dy, Eu, Y, Yb, Tm and Lu in thorium compounds has been developed. Sensibilities of 0.01 μg rare earths/g Th02 were achieved. The rare earth elements were chromatographycally separated in a nitric acid-ether-cellulose system. The solvent mixture was prepared by dissolving 11% of concentrated nitric acid in ether. The method is based upon the sorption of the rare earths on activated cellulose, the elements being eluted together with 0.01 M HNO 3 . The retention of the 152 , 154 Eu used as tracer was 99,4%. The other elements showed recoveries varying from 95 to 99%. A direct carrier destillation procedure for the spectrochemical determination of the mentioned elements was used. Several concentrations of silver chloride were used to study the volatility behavior of the rare earths. 2%AgCl was added to the matrix as definite carrier, being lantanum selected as internal standard. The average coefficient of variation for this method was +- -+ 7%. The method has been appleid to the analysis of rare earths in thorium coumpounds prepared by Thorium Purification Pilot Plant at Atomic Energy Institute, Sao Paulo [pt

  20. Mineral characterisation of Don Pao rare earth deposit in Vietnam

    International Nuclear Information System (INIS)

    XuanBen, T.

    1998-01-01

    Full text: The Don Pao Rare Earth Deposit was discovered in 1959 in Phon Tho district, about 450km North-West of Hanoi capital. Geological work was conducted between 1959-95, resulting in 60 ore bodies of various sizes being identified. The ore bodies are irregularly shaped nests, lenses and veins hosted in the shear zone, at the margin of a Paeleogene aged syenite massif. The mineral composition of Don Pao Deposit is very complex, consisting of more than 50 minerals. Among them, basnaesite, parisite, fluorite and barite are the main constituent minerals of the ore. All the minerals were identified by the modern methods of mineralogical studies. Based on the constituent mineral ratios, four ore types have been distinguished in the deposit: 1. Rare earth ore containing over 5 percent of RE 2 O 3 . 2. Rare Earth-Barite ore containing 0.5 to 30 percent of RE 2 O 3 . 3. Rare Earth-Barite-Fluorite ore containing 1 to 5 percent of RE 2 O 3 . 4. Rare Earth bearing Fluorite ore containing 1 to 5 percent of RE 2 O 3 . According to the benefication test, the ores in Don Pao can be enriched to a concentrate of 60 percent of RE 2 O 3 with a recover of 75 percent

  1. Rare Earth Elements - A New Challenge for the World Economy

    Directory of Open Access Journals (Sweden)

    Cristina Bumbac

    2013-01-01

    Full Text Available Rare Earth Elements or Rare Earth Metals (REM are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium and fifteen lanthanides. The term "rare earth" arises from the rare earth minerals from which they were first isolated. They are uncommon oxide-type minerals (earths found in Gandolinite extracted from one mine in Sweden. The first discovery was made in 1794, but it was only in 1940 that the scientist Frank Spedding developed an ion exchange procedure for separating and purifying the REM. For the next decades, they were hardly used in some "minor" industrial fields. Only after 2000 their importance grew, once the multitude of possibilities to use them was discovered due to technological progress. Now REM are incorporated into almost all modern technological devices: superconductors, magnets, electronic polishers, refining catalysts hybrid car components and military techniques. They are used in small quantities, but due to their extraordinary properties the prices are very high. The main problem is that China dominates this market, with 97% of total global supply. The highest concentration of rare earth metals are in Inner Mongolia in China, Mountain Pass in California U.S.A. and in Mount Weld in Australia. The developed countries are far behind China regarding production and are indeed depending on Chinese exports. Hence, there is a difficult situation on this particular market, with an uncertain future.

  2. Rare earth permanent magnets in China: production and raw materials

    International Nuclear Information System (INIS)

    Luo, Y.

    1998-01-01

    With the development of computer, electronics, communication and modern information industries, NdFeB magnet industry is growing rapidly as a booming business worldwide. Based on the abundance of rare earth and manpower, supporting by the technical teams and the huge domestic market, China NdFeB magnet industry made big jump during the last decade. Its growth rate is the highest one among all other countries. Now China occupies number one place in the world not only due to its richest rare earth reserves, but also due to its output of rare earth, especially, its sales to the international market. China is the only country, who is able to meet the market needs of rare earth worldwide. The current situation of NdFeB magnet industry can be concluded as ''five highs'', i.e. ''high volume growth'', ''high grade development'', ''high expansion of capacity'', ''high value added product'' and ''high variation speed''. The connotations of these ''five highs'' and a brief review on Chinese rare earth industry will be given in this paper. (orig.)

  3. Redox reactions in rare earth chloride molten electrolytes

    International Nuclear Information System (INIS)

    Khokhlov, V.A.; Novoselova, A.V.; Nikolaeva, E.V.; Tkacheva, O.Yu.; Salyulev, A.B.

    2007-01-01

    Rare earth (REM, Ln) solutions in chloride melts including MCI+LnCl 3 mixtures, where M - alkali metals, were investigated by potentiometry, voltammetry, conductometry in wide concentration and temperature intervals. Findings present complete and trusty information on the valent state of rare earths, structure and composition of complex ions affecting essentially on properties of electrolytes. It is demonstrated that the coexistence of rare earth ions with different oxidation level formed as a result of possible redox reactions: 2Ln 3+ + Ln ↔3Ln 2+ , Ln 2+ + Ln↔2Ln + and nM + + Ln↔nM + Ln n+ appears sharply in thermodynamic and transport properties of molten Ln-LnCl 3 and Ln-LnCl 3 -MCl systems [ru

  4. Thermal shock behavior of rare earth modified alumina ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Junlong; Liu, Changxia [Ludong Univ., Yantai (China). School of Transportation

    2017-05-15

    Alumina matrix ceramic composites toughened by AlTiC master alloys, diopside and rare earths were fabricated by hot-pressing and their thermal shock behavior was investigated and compared with that of monolithic alumina. Results showed that the critical thermal shock temperature (ΔT) of monolithic alumina was 400 C. However, it decreased to 300 C for alumina incorporating only AlTiC master alloys, and increased with further addition of diopside and rare earths. Improvement of thermal shock resistance was obtained for alumina ceramic composites containing 9.5 wt.% AlTiC master alloys and 0.5 wt.% rare earth additions, which was mainly attributed to the formation of elongated grains in the composites.

  5. Determination of the heavy rare earth radionuclides in melted rock

    International Nuclear Information System (INIS)

    Li Yinming; Wang Yalong; Zhang Quanshi

    1995-01-01

    There are some heavy rare earth radionuclides in the melted rocks, such as 160 Tb, 168,170 Tm, 88,91 Y, 174,177 Lu, 169 Yb, etc.. Because their contents are very low in the melted rocks and the light rare earth fission products are interfered with their determination, it is very complicated to measure them quantitatively. So a new method has been studied in which P507 resin is used to separate and purify the rare earths. Radioactive sources are prepared by the pieces of filter paper for determining chemical yield with X-fluorescence analysis, and radioactive activity is determined with the γ-spectra analysis. It is proved that this method has satisfied the demands of experiments

  6. Spectroscopic properties of rare earths in optical materials

    CERN Document Server

    Parisi, Jürgen; Osgood, R; Warlimont, Hans; Liu, Guokui; Jacquier, Bernard

    2005-01-01

    Aimed at researchers and graduate students, this book provides up-to-date information for understanding electronic interactions that impact the optical properties of rare earth ions in solids. Its goal is to establish a connection between fundamental principles and the materials properties of rare-earth activated luminescent and laser optical materials. The theoretical survey and introduction to spectroscopic properties include electronic energy level structure, intensities of optical transitions, ion-phonon interactions, line broadening, and energy transfer and up-conversion. An important aspect of the book lies in its deep and detailed discussions on materials properties and the potential of new applications such as optical storage, information processing, nanophotonics, and molecular probes that have been identified in recent experimental studies. This volume will be a valuable reference book on advanced topics of rare earth spectroscopy and materials science.

  7. Geological research on rare earth elements, results and outlook

    International Nuclear Information System (INIS)

    Fortin, H

    1999-01-01

    This is a report of the geological investigation of rare earth elements carried out by CCHEN and ENAMI (Empresa Nacional de Mineria) over 70,000 square kilometers in Chile's northern coastal mountain range. Twenty areas were identified with sphena, davidite, ilmenite, pyroxene, anatase and magnetite minerals containing 0.3 kg/t to 6.0 kg/t of rare earth elements. Additional research on Cerro Carmen Prospect, located near Diego de Almagro, define it as a metasomatic deposit, hosted in metamorphic contact rocks, between andesites (Pliensbachian to early Jurassic) and intrusive monzonitic rocks. This information increases knowledge about the metallogenesis of Chile's copper - iron - rare earth - uranium deposits and the application of this geological model of ore deposits as defined in Australia's Olympic Dam

  8. Determination of rare earth impurities in thorium by spectrographic methods

    Energy Technology Data Exchange (ETDEWEB)

    Wray, L W

    1957-08-15

    A method for determining rare earth impurities in thorium in the fractional ppm range is described. Before spectrographic examination is possible, the impurities must be freed from the thorium matrix. This is accomplished by removing the bulk of the thorium by extraction with TBP-CCl{sub 4} and the remainder by extraction with TTA-C{sub 6}H{sub 6}. This results in a consistent recovery of rare earths of about 85% with an average sensitivity of 0.2 ppm. The experimental error is within 10%. Details of the procedure are given together with working curves for the major neutron absorbing rare earths; i.e. dysprosium, europium, gadolinium and samarium. (author)

  9. Investigation and modelling of rare-earth activated waveguide structures

    International Nuclear Information System (INIS)

    Wolinski, W.; Malinowski, M.; Mossakowska-Wyszynska, A.; Piramidowicz, R.; Szczepanski, P.

    2005-01-01

    In this paper the overview of the recent study on the rare-earth activated waveguides performed in the Optoelectronic Department of IMiO is presented. We reported on the development of rare earth-doped fluorozirconate (ZBLAN) glass fibers that allow a construction of a new family of visible and ultraviolet fiber lasers pumped by upconversion. Especially the performance of holmium devices is presented. The properties of laser planar waveguides obtained by the LPE process and the growth conditions of rare earths doped YAG layers are presented. In this paper we present also the theoretical study of the nonlinear operation of planar waveguide laser, as an example the microdisk Nd:YAG structure is discussed. We derived an approximate formula which relates the small signal gain in the Nd:YAG active medium and the laser characteristics, obtained for whispering-gallery modes and radial modes, to the output power and real parameters of the laser structure (authors)

  10. Magnetic Partitioning Nanofluid for Rare Earth Extraction from Geothermal Fluids

    Energy Technology Data Exchange (ETDEWEB)

    McGrail, Bernard P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Liu, Jian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-08-21

    Rare earth metals are critical materials in a wide variety of applications in generating and storing renewable energy and in designing more energy efficient devices. Extracting rare earth metals from geothermal brines is a very challenging problem due to the low concentrations of these elements and engineering challenges with traditional chemical separations methods involving packed sorbent beds or membranes that would impede large volumetric flow rates of geothermal fluids transitioning through the plant. We are demonstrating a simple and highly cost-effective nanofluid-based method for extracting rare earth metals from geothermal brines. Core-shell composite nanoparticles are produced that contain a magnetic iron oxide core surrounded by a shell made of silica or metal-organic framework (MOF) sorbent functionalized with chelating ligands selective for the rare earth elements. By introducing the nanoparticles at low concentration (≈0.05 wt%) into the geothermal brine after it passes through the plant heat exchanger, the brine is exposed to a very high concentration of chelating sites on the nanoparticles without need to pass through a large and costly traditional packed bed or membrane system where pressure drop and parasitic pumping power losses are significant issues. Instead, after a short residence time flowing with the brine, the particles are effectively separated out with an electromagnet and standard extraction methods are then applied to strip the rare earth metals from the nanoparticles, which are then recycled back to the geothermal plant. Recovery efficiency for the rare earths at ppm level has now been measured for both silica and MOF sorbents functionalized with a variety of chelating ligands. A detailed preliminary techno-economic performance analysis of extraction systems using both sorbents showed potential to generate a promising internal rate of return (IRR) up to 20%.

  11. Peculiarities of rare-earth-element distribution in environmental objects

    International Nuclear Information System (INIS)

    Gorbunov, A.V.; Onischenko, T.L.; Gundorina, S.F.; Frontasyeva, M.V.

    1993-01-01

    The effect of the production of phosphorus fertilizers on the pollution of the environment by rare-earth elements is reviewed. The main sources of rare-earth element pollution in the environment are described. The levels of REEs in components of the environment - atmosphere, snow, different types of soil, native and agricultural types of vegetation - that provide evidence for their participation in the biological cycle of plants are considered. The high values of the correlation coefficients lead one to think that the REE distribution in vegetation occurs under specific laws true for this family of elements. (author) 9 refs.; 6 figs.; 5 tabs

  12. Rare earth aerosol analysis by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Citron, I.M.; Mausner, L.F.

    1982-01-01

    An analytical method for the determination of four lanthanides in air filter samples is described. The method involves simultaneous quantitative determinations of La, Ce, Pr, and Nd at the microgram level by x-ray fluorescence spectrometry without chemical separation of these rare earths and without serious interferences from the dust matrices on the filters. The method has been used successfully to analyze some air filter samples collected at a rare earth processing refinery in Illinois. A description of the development of the method is given as well as the results obtained by using this method on the air filter samples. The reproducibility of the results was generally +-5%

  13. Direct Reuse of Rare Earth Permanent Magnets—Coating Integrity

    DEFF Research Database (Denmark)

    Høgberg, Stig; Holbøll, Joachim; Mijatovic, Nenad

    2017-01-01

    Rare earth permanent magnets can be reused directly as an alternative to traditional recycling methods, in which scrapped magnets are reprocessed into new magnets by undergoing many of the original energy-intensive and expensive production processes. Direct reuse entails using segmented magnet...... assemblies built by several small standard-sized magnets that can be reused directly in a number of different applications. A central part of the direct reuse strategy is to separate and demagnetize magnets by heating them to the Curie temperature. We investigated the validity of direct reuse as a rare earth...

  14. Process to remove rare earth from IFR electrolyte

    International Nuclear Information System (INIS)

    Ackerman, J.P.; Johnson, T.R.

    1994-01-01

    The invention is a process for the removal of rare earths from molten chloride electrolyte salts used in the reprocessing of integrated fast reactor fuel (IFR). The process can be used either continuously during normal operation of the electrorefiner or as a batch process. The process consists of first separating the actinide values from the salt before purification by removal of the rare earths. After replacement of the actinides removed in the first step, the now-purified salt electrolyte has the same uranium and plutonium concentration and ratio as when the salt was removed from the electrorefiner. 1 fig

  15. Contribution for the studies of rare earth dithionates

    International Nuclear Information System (INIS)

    Schmitz, L.C.

    1988-01-01

    The main objective of this work is the synthesis and investigation of some properties of rare earth dithionates. The rare earth dithionates were prepared from the respective sulphates, by the reaction of the latter with BaS sub(2) O sub(6) in aqueous solutions. The lanthanide ion content was estimated by complexometric titration with EDTA; analysis for H were carried out by microanalysis and the water content was determinated by Karl Fischer titration. This experimental results in addition to thermogravimetric (TG) data gave the stoichiometry of the compounds. (author)

  16. Concentration of light rare earths process by amoniacal precipitation

    International Nuclear Information System (INIS)

    Aguilera, Y.; Rapado, M.; Consuegra, R.

    1996-01-01

    A procedure for the separation and concentration of light rare earths using a mixture of ammonia and water was developed. As a result technical concentrates of rare earths were obtained and the physical separation in the filtration step was improved. The filtration parameters (cake resistance r 0 and filtration web resistance R) were obtained for this process being they 5,5.10 11 cm/g and 3,4.10 13 cm -1 respectively. The proposed technology concentrates (Ce, La and Nd) with purities ranging from: 85-90 %, 85-87 % and 42-65 % respectively in only one precipitation step

  17. Spectrofluorimetric determination of rare earth elements using solidmatrix

    International Nuclear Information System (INIS)

    Suh, I.S.; Chi, K.Y.

    1982-01-01

    In this experiment, rare earth elements are separated from uranium by using the alumina column, anion exchange resin column, and 20% TOA in xylene and fluorescence characteristics were found in the solid matrix to analyze these elements without preseparation from each other. It becomes clear that the YVO 4 matrix is more sensitive than the Y 2 O 3 matrix when the red filter is used to minimized the second order peak intensity. And micro quantity of the rare earth elements in the yellow cake are analyzed by the using of the YVO 4 soid matrix. (Author)

  18. Synthesis and physicochemical investigation of adducts of rare earth thenoyltrifluoroacetonates

    Energy Technology Data Exchange (ETDEWEB)

    Anufrieva, S.I.; Snezhko, N.I.; Martynenko, L.I.; Pechurova, N.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

    1982-11-01

    Adducts of rare earth thenoyltrifluoroacetonates (3) have been synthesized with tributylphosphate (TBP), trioctylphosphenoxide (TOPO), triphenylphosphenoxide (TPO) of 1:1 and 1:2 composition as well as with ..cap alpha.., ..cap alpha..'-dipyridine (Dipy), o-phenanthroline (Phen) of 1:1 composition. The separated adducts have been studied by methods of element analysis, X-ray phase and derivatographic analyses and IR spectroscopy. It is shown that the adducts are more thermostable compared to the corresponding rare earth thenoyltrifluoroacetonate hydrates.

  19. The role of rare earths in narrow energy gap semiconductors

    International Nuclear Information System (INIS)

    Partin, D.L.; Heremans, J.; Morelli, D.T.; Thrush, C.M.

    1991-01-01

    Narrow energy band gap semiconductors are potentially useful for various devices, including infrared detectors and diode lasers. Rare earth elements have been introduced into lead chalcogenide semiconductors using the molecular beam epitaxy growth process. Europium and ytterbium increase the energy band gap, and nearly lattice-matched heterojunctions have been grown. In some cases, valence changes in the rare earth element cause doping of the alloy. In this paper some initial investigations of the addition of europium to indium antimonide are reported, including the variation of lattice parameter and optical transmission with composition and a negative magnetoresistance effect

  20. Rare Earths and Clean Energy: analyzing China's upper hand

    International Nuclear Information System (INIS)

    Seaman, J.

    2010-01-01

    An ominous but avoidable resource crunch in the so-called 'rare earth elements' is now threatening the development of a number of key industries from energy to defense to consumer electronics. As key components in the latest generation of technologies, including specialized magnets for windmills and hybrid cars, lasers for range finders and 'smart' munitions, and phosphors for LCD screens, demand for these rare metals is expected to grow rapidly in the years to come. But decades of under-investment in the mining and separation of these elements across the globe has left the industry ill-prepared to meet thi s growing demand. Over the years, only China has recognized the strategic significance of these resources and has succeeded in gaining a near monopoly on production, currently churning out 97% of the world' s rare earth oxides. Faced with problems of its own, and eager to use its resource advantage to master higher levels of value-added production of rare earth-dependent products, China has increasingly limited the rest of the world's access to these raw materials. This only complicates what was already projected to be a problematic resource shortage. This issue demands a higher quality of public debate. Rare earth consuming countries outside of China have only recently become aware of their dependence and started to take stock of the risks. Time is of the essence. Bringing new supplies online to meet growing demand is a long, complicated and risky process but is nevertheless necessary to ensure the development of high tech industries, notably clean energy. Accessible reserves of rare earths do exist outside of China and mitigating the effects of the looming shortage requires opening up these reserves to production. Yet, as the Chinese experience attests, there are substantial risks to the environment associated with mining and separating rare earths. Care must be taken to ensure responsible mining practices across the globe. Longer-term solutions, such as

  1. Recovery and purification of rare earth elements and thorium

    International Nuclear Information System (INIS)

    Sungur, A.; Saygi, Z.; Yildiz, H.

    1985-01-01

    Rare earth elements and thorium found in the low-grade Eskisehir-Beylikahir ore have been recovered by HCl leaching, Lanthanides and thorium were separated and purified from the leach solutions through the precipitation sequence as double sulphate, hydroxide and oxalate. The Ln 2 O 3 and Th(OH) 4 products, finally obtained contained 36% Ce and 65% Th. The analysis of rare earth elements, thorium and other present ingredients were carried out by instrumental neutron activation analysis, atomic absorption spectroscopy, vis-spectroscopy and gravimetry. (author)

  2. Uptake of rare earth elements by dryopteris erythrosora (autumn fern)

    International Nuclear Information System (INIS)

    Ozaki, Takuo; Enomoto, Shuichi

    2001-01-01

    Mechanisms of uptake of rare earth elements (REEs) were investigated, particularly those by REE accumulator species (autumn fern). Rare earth elements are practically insoluble under natural conditions, suggesting some unknown mechanisms in REE accumulator species. In the present investigation, two notable phenomena were observed. (1) Concerning the ionic-radius dependence of REE uptake by leaves, nonaccumulator species showed an extremely high uptake for Y compared with the adjacent-ionic-radius REEs in the multitracer, while accumulator species showed no anomaly. (2) REE uptake by autumn fern was influenced by the addition of chelating chemical reagents in the uptake solution, while no effect was observed for nonaccumulator species. (author)

  3. Separation of rare earth metal using micro solvent extraction system

    International Nuclear Information System (INIS)

    Nishihama, S.; Tajiri, Y.; Yoshizuka, K.

    2005-01-01

    A micro solvent extraction system for the separation of rare earth metals has been investigated. The micro flow channel was fabricated on a PMMA plate. Extraction equilibrium was quickly achieved, without any mechanical mixing. The solvent extraction results obtained for the Pr/Sm binary solutions revealed that both rare earth metals are firstly extracted together. Following, the Pr is extracted in the organic solution and Sm remains in the aqueous phase. The phase separation can be successively achieved by contriving the cross section of the flow channel

  4. Low-spin identical bands in odd-A nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Baktash, C; Garrett, J D; Winchell, D F; Smith, A [Oak Ridge National Lab., TN (United States)

    1992-08-01

    A comprehensive study of odd-A rotational bands in normally-deformed rare-earth nuclei indicates that a large number of seniority-one configurations (30% for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models, based on the traditional picture of nuclear pair correlation in vogue for more than three decades, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority. (author). 18 refs., 1 tab., 1 fig.

  5. Low-spin identical bands in odd-A nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Garrett, J.D.; Winchell, D.F.; Smith, A.

    1992-01-01

    A comprehensive study of odd-A rotational bands in normally-deformed rare-earth nuclei indicates that a large number of seniority-one configurations (30% for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models, based on the traditional picture of nuclear pair correlation in vogue for more than three decades, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority

  6. Low-spin identical bands in odd-A nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Garrett, J.D.; Winchell, D.F.; Smith, A.

    1992-01-01

    A comprehensive study of odd-A rotational bands in normally-deformed rare-earth nuclei indicates that a large number of seniority-one configurations (30% for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models, based on the traditional picture of nuclear pair correlation in vogue for more than three decades, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority. (author). 18 refs., 1 tab., 1 fig

  7. On the Orientation Barrier Distribution of the interacting spherical- Deformed Nuclei

    International Nuclear Information System (INIS)

    Ismail, M.; Seif, W.M.

    2009-01-01

    The effect of different multipole deformations on the Coulomb barrier distribution in the orientation degrees of freedom is studied. The demonstrated Coulomb barriers are calculated microscopically using the double folding model which is based on realistic density dependent nucleon nucleon interaction. A simple straight forward method, presented in recent work, has been used to predict the distribution of barriers at arbitrary orientations in presence of different deformations far away the complicated numerical calculations. The proposed interpretation is related to the half density radius change of the deformed nucleus involved in interaction where the orientation Coulomb barrier parameters distributions show similar patterns to that of orientation deformed nucleus one. The orientation Coulomb barrier radius distribution follows the same variation of the deformed nucleus radius, while the barrier height distribution is directly proportional to it. This correlation allows a simple evaluation of the orientation barrier distribution which greatly helps us to estimate when the barrier parameters will increase or decrease and at which orientations they will be independent of the deformation. It helps also to estimate the optimum orientations for hot and cold fusion of colliding nuclei.

  8. On the study of level density parameters for some deformed light nuclei

    International Nuclear Information System (INIS)

    Sonmezoglu, S.

    2005-01-01

    The nuclear level density, which is the number of energy levels/MeV at an excitation energy Ex , is a characteristic property of every nucleus. Total level densities are among the key quantities in statistical calculations in many fields, such as nuclear physics, astrophysics, spallation s neutrons measurements, and studies of intermediate-energy heavy-ion collisions. The nuclear level density is an important physical quantity both from the fundamental point of view as well as in understanding the particle and gamma ray emission in various reactions. In light and heavy deformed nucleus, the gamma-ray energies drop with decreasing spin in a very regular fashion. The nuclear level density parameters have been usually used in investigation of the nuclear level density. This parameter itself changes with excitation energy depending on both shell effect in the single particle model and different excitation modes in the collective models. In this study, the energy level density parameters of some deformed light nucleus (40 C a, 47 T i, 59 N i, 79 S e, 80 B r) are determined by using energy spectrum of the interest nucleus for different band. In calculation of energy-level density parameters dependent upon excitation energy of nuclei studied, a model was considered which relies on the fact that energy levels of deformed light nuclei, just like those of deformed heavy nuclei, are equidistant and which relies on collective motions of their nucleons. The present calculation results have been compared with the corresponding experimental and theoretical results. The obtained results are in good agreement with the experimental results

  9. Micromagnetics of rare-earth efficient permanent magnets

    Science.gov (United States)

    Fischbacher, Johann; Kovacs, Alexander; Gusenbauer, Markus; Oezelt, Harald; Exl, Lukas; Bance, Simon; Schrefl, Thomas

    2018-05-01

    The development of permanent magnets containing less or no rare-earth elements is linked to profound knowledge of the coercivity mechanism. Prerequisites for a promising permanent magnet material are a high spontaneous magnetization and a sufficiently high magnetic anisotropy. In addition to the intrinsic magnetic properties the microstructure of the magnet plays a significant role in establishing coercivity. The influence of the microstructure on coercivity, remanence, and energy density product can be understood by using micromagnetic simulations. With advances in computer hardware and numerical methods, hysteresis curves of magnets can be computed quickly so that the simulations can readily provide guidance for the development of permanent magnets. The potential of rare-earth reduced and rare-earth free permanent magnets is investigated using micromagnetic simulations. The results show excellent hard magnetic properties can be achieved in grain boundary engineered NdFeB, rare-earth magnets with a ThMn12 structure, Co-based nano-wires, and L10-FeNi provided that the magnet’s microstructure is optimized.

  10. Electron-phonon coupling in the rare-earth metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Mertig, I.

    1990-01-01

    -phonon parameters were calculated within the Gaspari-Gyorffy formulation. For the heavier rare earths Gd–Tm spin polarization was included both in the band-structure calculations and in the treatment of the electron-phonon coupling to take into account the spin splitting of the conduction electrons induced by the 4...

  11. Supramolecular structures constructed from three novel rare earth ...

    Indian Academy of Sciences (India)

    Supramolecular structures constructed from three novel rare earth metal complexes. HUAZE DONGa,∗, XIAOJUN FENGb,∗, XIA LIUc, BIN ZHENGa, JIANHONG BIa, YAN XUEa,. SHAOHUA GOUd and YANPING WANGa. aDepartment of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China.

  12. Crystallization of mixed rare earth (didymium) molybdates in silica gel

    Indian Academy of Sciences (India)

    Experiments on the growth of mixed rare earth (didymium—a combination of La, Nd, Pr and Sm) molybdates in silica gel medium are reported. The optimum conditions conducive for the growth of these crystals are described and discussed. Concentration programming is reported to enhance the size of crystals by two-fold; ...

  13. A divalent rare earth oxide semiconductor: Yttrium monoxide

    Science.gov (United States)

    Kaminaga, Kenichi; Sei, Ryosuke; Hayashi, Kouichi; Happo, Naohisa; Tajiri, Hiroo; Oka, Daichi; Fukumura, Tomoteru; Hasegawa, Tetsuya

    Rare earth sesquioxides like Y2O3 are known as widegap insulators with the highly stable closed shell trivalent rare earth ions. On the other hand, rare earth monoxides such as YO have been recognized as gaseous phase, and only EuO and YbO were thermodynamically stable solid-phase rock salt monoxides. In this study, solid-phase rock salt yttrium monoxide, YO, was synthesized in a form of epitaxial thin film by pulsed laser deposition method. YO possesses unusual valence of Y2+ ([Kr] 4d1) . In contrast with Y2O3, YO was narrow gap semiconductor with dark-brown color. The electrical conductivity was tunable from 10-1 to 103 Ω-1 cm-1 by introducing oxygen vacancies as electron donor. Weak antilocalization behavior was observed indicating significant spin-orbit coupling owing to 4 d electron carrier. The absorption spectral shape implies the Mott-Hubbard insulator character of YO. Rare earth monoixdes will be new platform of functional oxides. This work was supported by JST-CREST, the Japan Society for the Promotion of Science (JSPS) with Grant-in-Aid for Scientific Research on Innovative Areas (Nos. 26105002 and 26105006), and Nanotechnology Platform (Project No.12024046) of MEXT, Japan.

  14. Dissolved rare earth elements in the Black Sea

    NARCIS (Netherlands)

    Schijf, Johan; Baar, Hein J.W. de; Wijbrans, Jan R.; Landing, William M.

    1991-01-01

    Concentrations of rare earths in the deep anoxic Black Sea are about one order of magnitude higher than in normal open ocean waters. From a minimum at the suboxic-anoxic interface at about 107 m depth, concentrations increase strongly to a maximum at about 300–400 m depth. Concentrations of Ce range

  15. An introduction to the economics of rare earths

    NARCIS (Netherlands)

    Bartekova, E.

    2014-01-01

    The aim of this paper is to examine the supply risk of rare earths and its impact on low carbon technologies deployment. Bringing together seemingly disconnected strands of scientific literature, this multidisciplinary approach allows to provide an overarching overview of the economics of rare

  16. Advanced system for separation of rare-earth fission products

    International Nuclear Information System (INIS)

    Baker, J.D.; Gehrke, R.J.; Greenwood, R.C.; Meikrantz, D.H.

    1982-01-01

    A microprocessor-controlled radiochemical separation system has been further advanced to separate individual rare-earth elements from mixed fission products in times of a few minutes. The system was composed of an automated chemistry system fed by two approximately 300 μg 252 Cf sources coupled directly by a He-jet to transport the fission products. Chemical separations were performed using two high performance liquid chromatography columns coupled in series. The first column separated the rare-earth group by extraction chromatography using dihexyldiethylcarbamoylmethylphosphonate (DHDECMP) adsorbed on Vydac C 8 resin. The second column isolated the individual rare-earth elements by cation exchange chromatography using Aminex A-9 resin with α-hydroxyisobutyric acid (α-HIBA) as the eluent. Significant results, which have been obtained to date with this advanced system, are the identification of several new neutron-rich rare-earth isotopes including 155 Pm (T=48+-4 s) and 163 Gd (T=68+-3 s). In addition, a half-life of 41+-4 s is reported for 160 Eu. (author)

  17. Production of a tracer packet of heavier rare earth elements

    International Nuclear Information System (INIS)

    Lahiri, S.; Nayak, D.; Maji, S.

    2004-01-01

    Production of a tracer packet of heavier rare earth elements containing carrier-free radionuclides of 153,155 Tb, 153,155,157 Dy, 159 Ho, 159,161 Er, 161 Tm produced by medium energy 7 Li and 12 C irradiation on an europium oxide target and the subsequent separation of bulk europium from the carrier-free products is described. (author)

  18. Recovery of uranium and of rare earths from Moroccan phosphates

    International Nuclear Information System (INIS)

    Ezahr, I.; El Houari, A.; Smani, S.M.

    1984-01-01

    The contents of uranium and of rare earths in Moroccan phosphates vary from 75 to 250 ppm and from 900 to 1500 ppm, respectively. The phosphates produced in Morocco contain therefore about 2500 t of uranium and 25 000 t of rare earths, compared with annual productions of uranium and of rare earths of 43 000 t and 33 000 t, respectively. During the sulphuric leaching of the phosphate ores, uranium is found to 80-90% in the phosphoric acid. Research into the extraction of uranium has shown that for the phosphoric acids produced at Safi the coefficient of extraction: is not very sensitive to the P 2 O 5 concentration on the 28-30% region; is not affected by the sulphur level up to the concentration of 4%; is very sensitive to the fluorine content beyond 1%. On the level of the first cycle of the process in Depa-Topo, four extraction stages permit a yield of between 92 and 98% to be reached. The addition of an oxidizing agent to the phosphoric acids under examination was not necessary, as their potential level is high. The purity of the yellow-cakes obtained varies from 94 to 99%. The overall recovery efficiency lies between 67 and 71%. In a second part, this paper deals with the recovery of the rare earths [fr

  19. On the luminescence of perovskite type rare earth gallates

    International Nuclear Information System (INIS)

    Jianmei, Y.; Qingyuan, W.; Shuzhen, L.; Lianren, S.; Mingyu, C.

    1985-01-01

    It has been reported that perovskite type lanthanum gallates may be a good host material for laser and luminescence, but in the rare earth gallates studied, the numbers of perovskite type are less than that of the garnet type and there is less report on their spectroscopic properties in the literature. In this paper synthesis and spectroscopic properties of these compounds are studied

  20. The symmetries of magnetic structures in rare earth tetraborides

    International Nuclear Information System (INIS)

    Schaefer, W.; Will, G.; Buschow, K.H.J.

    1975-01-01

    The collinear antiferromagnetic spin configurations, which are possible in the rare earth tetraboride structure (space group P 4/mbm) and their distinction by neutron diffraction are discussed. The symmetries of the different antiferromagnetic structures are described by the corrosponding magnetic space groups. Neutron diffraction data collected from ErB 4 are integrated in the structure discussion. (orig.) [de

  1. Rare earth point defects in GaN

    Energy Technology Data Exchange (ETDEWEB)

    Sanna, S.

    2007-12-14

    In this work we investigate rare earth doped GaN, by means of theoretical simulations. The huge unit cells necessary to model the experimental system, where dilute amount of rare earth ions are used, are handled with the charge self consistent density-functional based-tight binding (SCC-DFTB) calculational scheme. The method has been extended to include LDA+U and simplified self interaction corrected (SIC)-like potentials for the simulation of systems with localised and strongly correlated electrons. A set of tight-binding parameters has been created to model the interaction of GaN with some dopants, including a selection of lanthanide ions interesting due to their optical or magnetic properties (Pr, Eu, Gd, Er and Tm). The f-electrons were treated as valence electrons. A qualitatively correct description of the band gap is crucial for the simulation of rare earth doped GaN, because the luminescence intensity of the implanted samples depends on the size of the host band gap and because the rare earths could introduce charge transition levels near the conduction band. In this work these levels are calculated with the Slater-Janak (SJ) transition state model, which allows an approximate calculation of the charge transition levels by analysing the Kohn-Sham eigenvalues of the DFT. (orig.)

  2. Local magnetism in rare-earth metals encapsulated in fullerenes

    NARCIS (Netherlands)

    De Nadai, C; Mirone, A; Dhesi, SS; Bencok, P; Brookes, NB; Marenne, [No Value; Rudolf, P; Tagmatarchis, N; Shinohara, H; Dennis, TJS; Marenne, I.; Nadaï, C. De

    Local magnetic properties of rare-earth (RE) atoms encapsulated in fullerenes have been characterized using x-ray magnetic circular dichroism and x-ray absorption spectroscopy (XAS). The orbital and spin contributions of the magnetic moment have been determined through sum rules and theoretical

  3. Preparation and characteristics of various rare earth nitrides

    International Nuclear Information System (INIS)

    Imamura, H.; Imahashi, T.; Zaimi, M.; Sakata, Y.

    2008-01-01

    Active nanocrystalline nitrides of EuN and YbN with high surface areas were successfully prepared by the thermal decomposition of the rare earth amides (Eu(NH 2 ) 2 , Yb(NH 2 ) 2 and Yb(NH 2 ) 3 ). For the preparation of CeN, PrN and NdN, the direct reaction of the rare earth metals with ammonia was extensively studied to determine optimal conditions. In the reaction of rare earth metals with ammonia, hydrides besides the nitrides were competitively formed. The reaction conditions such as temperatures and ratios of ammonia to rare earth metal were crucial in preferential formation of nitride. The nanocrystalline YbN and EuN readily absorbed large amounts of ammonia even at room temperature upon contact with ammonia (13.3 kPa). The absorbed ammonia existed in at least two forms on/in the nitride; the one was surface-adsorbed ammonia and the other ammonia absorbed in the nitride in a decomposed state. The properties of ammonia absorbed by the nitride were further evaluated by temperature-programmed desorption (TPD), FT-IR and XRD techniques

  4. Direct current electroluminescence in rare-earth-doped zinc sulphide

    International Nuclear Information System (INIS)

    Bryant, F.J.; Krier, A.

    1984-01-01

    Some of the properties and characteristics of rare-earth-doped zinc sulphide DCEL devices are reported. Two types of devices are discussed, co-evaporated ZnS:RE thin films and ion implanted ZnS:RE single crystal diodes. The thin film devices exhibit bright DCEL of various colours at low applied voltages (typically approximately 12 V). A study of the spectral intensities and lifetimes of the Er 3+ ion in ZnS:Er 3+ thin films is consistent with a Boltzmann energy distribution amongst the conduction electrons present in these devices. The ZnS:RE single crystal diodes fabricated in this laboratory by ion implantation are also capable of various colour DCEL. By comparing the EL emission obtained from the different rare earth dopants, erbium and neodymium are identified as the most efficient luminescence centres. Further consideration of the EL emission spectra gives evidence for the presence of inter-conduction band hot electron transitions in those devices containing rare earth dopants which are inefficent electroluminescence centres. These findings can be explained in terms of Auger processes occurring in rare earth complexes. (author)

  5. Crystalline and amorphous rare-earth metallic compounds

    International Nuclear Information System (INIS)

    Burzo, E.

    1975-01-01

    During the last years the study of magnetic behaviour of rare-earth (or yttrium) compounds with cobalt and iron has growth of interest. This interest of justified by a large area of experimental and theoretical problems coming into being in the study of some rare-earth materials as well as in their technical applications. In the last three years a great number of new rare earth materials were studied and also new models explaining the magnetic behaviour of these systems have been used. In this paper we refer especially to some typical systems in order to analyse the magnetic behaviour of iron and cobalt and also the part played by the magnetic interactions in the values of the cobalt or iron moments. The model used will be generally the molecular field model. In the second chapter we present comparatively the structure of crystalline and amorphous compounds for further correlation with the magnetic properties. In chapter III we analyse the magnetic interactions in some crystalline and amorphous rare-earth alloys. Finally, we exemplify the ways in which we ensure better requried characteristics by the technical utilizations of these materials. These have in view the modifications of the magnetic interactions and are closely related with the analysis made in chapter III

  6. Uncovering the end uses of the rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Du, Xiaoyue, E-mail: xiaoyue.du@empa.ch [Swiss Federal Laboratories for Materials Science and Technology (EMPA), Lerchenfeldstrasse 5, 9014 St. Gallen (Switzerland); Yale University, 195 Prospect Street, New Haven CT 06511 (United States); Graedel, T.E. [Yale University, 195 Prospect Street, New Haven CT 06511 (United States)

    2013-09-01

    The rare earth elements (REE) are a group of fifteen elements with unique properties that make them indispensable for a wide variety of emerging and conventional established technologies. However, quantitative knowledge of REE remains sparse, despite the current heightened interest in future availability of the resources. Mining is heavily concentrated in China, whose monopoly position and potential restriction of exports render primary supply vulnerable to short term disruption. We have drawn upon the published literature and unpublished materials in different languages to derive the first quantitative annual domestic production by end use of individual rare earth elements from 1995 to 2007. The information is illustrated in Sankey diagrams for the years 1995 and 2007. Other years are available in the supporting information. Comparing 1995 and 2007, the production of the rare earth elements in China, Japan, and the US changed dramatically in quantities and structure. The information can provide a solid foundation for industries, academic institutions and governments to make decisions and develop strategies. - Highlights: • We have derived the first quantitative end use information of the rare earths (REE). • The results are for individual REE from 1995 to 2007. • The end uses of REE in China, Japan, and the US changed dramatically in quantities and structure. • This information can provide solid foundation for decision and strategy making.

  7. Electrons and Spin Waves in Heavy Rare Earth Metals

    DEFF Research Database (Denmark)

    Mackintosh, A. R.

    1972-01-01

    this understanding on a more quantitative basis. The experimental evidence on the electronic structure of the rare earths is still rather meager but, so far as it goes, is in accord with the detailed description provided by band structure calculations. On the other hand, the experimental study of the magnon...

  8. Mechanism of structural type formation of rare earth polychalcogenides

    International Nuclear Information System (INIS)

    Kuz'micheva, G.M.; Eliseev, A.A.; Khalina, S.Yu.

    1981-01-01

    It proved to be possible to obtain the structural motives not only of all the known polychalcogenides of rare earth elements but to forecast compounds not yet existing on the basis of two initial structural motives. All the structural motives can be divided into superstructures and polytypes as to the mechanism of their formation [ru

  9. Systematic hardness measurements on some rare earth garnet ...

    Indian Academy of Sciences (India)

    Unknown

    Microhardness measurements were undertaken on twelve rare earth garnet crystals. In yttrium aluminium garnet and gadolinium ... syan (1997) has quoted a single value for Gd3Sc2Ga3O12. In the present study measurements have ... small and within the limits of experimental error. There- fore, where pure garnet crystals ...

  10. Rare earth intermetallic compounds produced by a reduction-diffusion process

    International Nuclear Information System (INIS)

    Cech, R.E.

    1975-01-01

    A reduction-diffusion process is given for producing novel rare earth intermetallic compounds, such as cobalt--rare earth intermetallic compounds, especially compounds useful in preparing permanent magnets. A particulate mixture of rare earth metal halide, cobalt and calcium hydride is heated to effect reduction of the rare earth metal halide and to diffuse the resulting rare earth metal into the cobalt to form the intermetallic compound

  11. Environmental aspects in the processing of rare earth ores and minerals

    International Nuclear Information System (INIS)

    Bhattacharya, R.

    2011-01-01

    In India, rare earths are extracted from the mineral monazite which occurs abundantly along with other heavy minerals in the coastal beach sands. Monazite, apart from rare earths, also contains uranium and thorium. Rare earths can be obtained from monazite either by acid digestion route or by alkaline digestion route. In India, although pilot scale studies have been carried out extraction of rare earths by acid digestion route, however, alkali digestion route has been predominantly followed for commercial extraction of rare earths

  12. Program package for calculation of cross sections of neutron scattering on deformed nuclei by the coupled-channel method

    International Nuclear Information System (INIS)

    Kloss, Yu.Yu.

    1985-01-01

    Program package and numerical solution of the problem for a system of coupled equations used in optical model to solve a problem on low and mean energy neutron scattering on deformed nuclei, is considered. With these programs differnet scattering cross sections depending on the incident neutron energy on even-even and even-odd nuclei were obtained. The programm permits to obtain different scattering cross sections (elastic, inelastic), excitation cross sections of the first three energy levels of rotational band depending on the energy, angular distributions and neutron polarizations including excited channels. In the program there is possibility for accounting even-even nuclei octupole deformation

  13. International strategic minerals inventory summary report; rare-earth oxides

    Science.gov (United States)

    Jackson, W.D.; Christiansen, Grey

    1993-01-01

    Bastnaesite, monazite, and xenotime are currently the most important rare-earth minerals. Bastnaesite occurs as a primary mineral in carbonatites. Monazite and xenotime also can be found in primary deposits but are recovered principally from heavy-mineral placers that are mined for titanium or tin. Each of these minerals has a different composition of the 15 rare-earth elements. World resources of economically exploitable rare-earth oxides (REO) are estimated at 93.4 million metric tons in place, composed of 93 percent in primary deposits and 7 percent in placers. The average mineral composition is 83 percent bastnaesite, 13 percent monazite, and 4 percent of 10 other minerals. Annual global production is about 67,000 metric tons of which 41 percent is from placers and 59 percent is from primary deposits; mining methods consist of open pits (94 percent) and dredging (6 percent). This output could be doubled if the operations that do not currently recover rare earths would do so. Resources are more than sufficient to meet the demand for the predictable future. About 52 percent of the world's REO resources are located in China. Ranking of other countries is as follows: Namibia (22 percent), the United States (15 percent), Australia (6 percent), and India (3 percent); the remainder is in several other countries. Conversely, 38 percent of the production is in China, 33 percent in the United States, 12 percent in Australia, and 5 percent each in Malaysia and India. Several other countries, including Brazil, Canada, South Africa, Sri Lanka, and Thailand, make up the remainder. Markets for rare earths are mainly in the metallurgical, magnet, ceramic, electronic, chemical, and optical industries. Rare earths improve the physical and rolling properties of iron and steel and add corrosion resistance and strength to structural members at high temperatures. Samarium and neodymium are used in lightweight, powerful magnets for electric motors. Cerium and yttrium increase the

  14. Rare earth element lithogeochemistry of granitoid mineral deposits

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R.P.; Fryer, B.J. (Memorial Univ. of Newfoundland, St. John' s (Canada). Dept. of Earth Sciences)

    1983-12-01

    As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth elements, reflecting their high pH, low fluid/rock ratios, and the dominant role of Cl/sup -/ complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F/sup -/ and CO/sub 3//sup 2 -/ become important in metal (e.g. Mo, W) transport through complexing, and their activity in the hydrothermal fluids is illustrated by mobilization of the heavy rare earth elements. The relative involvement of Cl/sup -/ versus F/sup -/ versus CO/sub 3//sup 2 -/ in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F/sup -/ and CO/sub 3//sup 2 -/ in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geochemistry, particularly when integrated with fluid inclusion and isotope studies, can provide l) an effective method for identifying the physiochemical controls of metal transport and 2) a useful criterion of elucidating metal distribution.

  15. Rare earth element lithogeochemistry of granitoid mineral deposits

    International Nuclear Information System (INIS)

    Taylor, R.P.; Fryer, B.J.

    1983-01-01

    As a monitor of the processes involved in the formation of granitoid mineral deposits the coherent group behaviour of the rare earth elements (REE) actively reflects changing fluid characteristics. For example, in the porphyry environment, magmatic-hydrothermal fluids produce potassic alteration with strong enrichment in the light rare earth elements, reflecting their high pH, low fluid/rock ratios, and the dominant role of Cl - complexing in metal (i.e. Cu, Au) transport. With increasing fluid/rock ratios and decreasing pH accompanying the progressive involvement of meteoric fluids (and the production of propylitic, argillic, and phyllic alteration) anionic species such as F - and CO 3 2- become important in metal (e.g. Mo, W) transport through complexing, and their activity in the hydrothermal fluids is illustrated by mobilization of the heavy rare earth elements. The relative involvement of Cl - versus F - versus CO 3 2- in metal transport in other granite-related systems can also be monitored through REE behaviour. Hence granitoid tin-tungsten mineralization and associated greisenization typically exhibit heavy rare earth enrichment and evidence the importance of F - and CO 3 2- in metal transport. Similarly, heavy rare earth element enrichment in hydrothermal uranium deposits can be related to the transport of uranium as carbonate complexes. REE are widely accepted as powerful tools in the study of rock petrogenesis, but their use has been neglected in the investigation of mineral deposits. The recognition of the systematic variation of REE distributions in granitoid mineral deposits suggests that the application of REE geochemistry, particularly when integrated with fluid inclusion and isotope studies, can provide l) an effective method for identifying the physiochemical controls of metal transport and 2) a useful criterion of elucidating metal distribution

  16. Crystal chemistry and magnetic properties of ternary rare earth sulfides

    International Nuclear Information System (INIS)

    Plug, C.M.; Rijksuniversiteit Leiden

    1977-01-01

    The results of magnetic measurements on two groups of ternary rare earth sulphides are described, the MLnS 2 (M=Li, Na, K) type of compounds and the series Ln 2 ZrS 5 , where Ln denotes one of the rare earths. None of these compounds is metallic, excluding the possibility of RKKY-interaction. In chapter II a survey of the relevant theory on magnetic properties and crystal field splitting is given. In spite of the similarity in chemical properties of the rare earths, the crystal chemistry of their compounds is rather complex. This is due to the lanthanide contraction. The third chapter deals with the description and classification of the numerous crystal structures of both ternary and binary rare earth sulphides that have been observed. Rather simple relations between various structures are presented using a new method of structure classification. The magnetic interactions expected to be based on superexchange via the anions, which is usually very structure dependent. Experiments to study the crystallographic ordering, applying both X-ray and electron diffraction methods and the results of the magnetic measurements on the compounds MLnS 2 are reported in chapter IV. The compounds Ln 2 ZrS 5 are candidates for a systematic study of the variation of the magnetic properties along the rare earth series. The results of magnetic measurements on these compounds are presented in chapter V, combined with the results of specific heat measurements. Also the magnetic structure of two representatives, Tb 2 ZrS 5 and Dy 2 ZrS 5 , determined by neutron diffraction experiments below the ordering temperature, is reported

  17. Separation of Rare Earths from Uranium and Thorium

    International Nuclear Information System (INIS)

    Krebs, Damien

    2014-01-01

    Greenland Minerals and Energy - Key Highlights – A unique world class mining project: 1. World-class, large scale development project: • Economically robust, proven technology, large-scale, long life production of rare earths concentrate and uranium; • Large JORC resource base to produce ~7kt HREO, 37kt LREO & 3Mlbs U_3O_8 per annum over 30 year mine life; • Ideally located near international airport, existing towns and potential hydro-electric power source. 2. Very attractive commodity portfolio: • Heavy rare earths and uranium are both recognised as strategically important commodities for the future; • Rare earths market characterised by limited capacity and increasing demand (particularly Dy, Nd, Tb, Eu and Y). 3. Strong management and technical team: • Experienced management team with proven track record; • Well-respected and knowledgeable technical/project team in place with exceptional local expertise. 4. Highly advantageous ore-type, makes for simple cost-effective processing, highly scalable production: • High upgrade through beneficiation brings optionality to Kvanefjeld project; • Leaching can be done in Greenland, or owing to the high-grade concentrate, can be shipped to other locations; • Allows to single concentrator in Greenland, multiple refineries/partners globally. 5. Globally significant, long life, low cost, multi-commodity asset: • Company to become one of the largest producers of rare earths globally and a significant U_3O_8 mine; • Potential to supply >20% of global critical (including heavy) rare earth element demand; • Company has low cost of production due to multiple by-product opportunities. 6. Low political risk: • Stable, low-risk operating environment with government looking to develop new industries and employment; • GME fully permitted to evaluate the project, exploration licence now includes radioactive elements; • Management and board have a solid working relationship with the government and are

  18. Relativistic deformed mean-field calculation of binding energy differences of mirror nuclei

    International Nuclear Information System (INIS)

    Koepf, W.; Barreiro, L.A.

    1996-01-01

    Binding energy differences of mirror nuclei for A=15, 17, 27, 29, 31, 33, 39 and 41 are calculated in the framework of relativistic deformed mean-field theory. The spatial components of the vector meson fields and the photon are fully taken into account in a self-consistent manner. The calculated binding energy differences are systematically smaller than the experimental values and lend support to the existence of the Okamoto-Nolen-Schiffer anomaly found decades ago in nonrelativistic calculations. For the majority of the nuclei studied, however, the results are such that the anomaly is significantly smaller than the one obtained within state-of-the-art nonrelativistic calculations. (author). 35 refs

  19. Generalized vibrating potential model for collective excitations in spherical, deformed and superdeformed systems: (1) atomic nuclei, (2) metal clusters

    International Nuclear Information System (INIS)

    Nesterenko, V.O.; Kleinig, W.

    1995-01-01

    The self-consistent vibrating potential model (VPM) is extended for description of Eλ collective excitations in atomic nuclei and metal clusters with practically any kind of static deformation. The model is convenient for a qualitative analysis and provides the RPA accuracy of numerical calculations. The VPM is applied to study Eλ giant resonances in spherical metal clusters and deformed and superdeformed nuclei. It is shown that the deformation splitting of superdeformed nuclei results in a very complicated (''jungle-like'') structure of the resonances, which makes the experimental observation of E2 and E3 giant resonances in superdeformed nuclei quite problematic. Calculations of E1 giant resonance in spherical sodium clusters Na 8 , Na 20 and Na 40 are presented, as a test of the VPM in this field. The results are in qualitative agreement with the experimental data. (orig.)

  20. Diffraction scattering and disintegration of complex particles by nonspherical deformable nuclei

    International Nuclear Information System (INIS)

    Evlanov, M.V.; Isupov, V.Y.; Tartakovskii, V.K.

    1989-01-01

    We study the dependence of the differential and integrated cross sections for diffraction scattering and disintegration of complex particles by axially symmetric and non-axially-symmetric nuclei on the shape, deformability, and diffuseness of the nuclear surface, and also on the structure of the incident particles and rescattering processes. It is shown that when all of these factors are taken into account, as well as the interaction in the final state between the disintegration products of the incident particle, a satisfactory description of complicated coincidence experiments can be obtained, and also inelastic scattering experiments with excitation of collective states of the target nucleus

  1. One-phonon states in deformed nuclei for isoscalar and isovector interactions

    International Nuclear Information System (INIS)

    Malov, L.A.; Nesterenko, V.O.; Solov'ev, V.G.

    1977-01-01

    Extension of the formulas describing the one-phonon states of compound even-even deformed nuclei to the case when the isoscalar and isovector multipole-multipole forces are taken into account, is given. The formalism presented makes it possible to obtain an unified description of the low-lying states and gigantic multipole resonances. Procedure is developed which makes it possible to write down the reduced probability and energetically weighted sum rule in the form of force functions averaged over certain interval of energies. The procedure simplifies the calculations significantly and makes it possible to avoid solving the secular equation for energies of one-phonon states

  2. Generalized Michailov plot analysis of inband E2 transitions of deformed nuclei

    International Nuclear Information System (INIS)

    Long, G.L.; Zhang, W.L.; Ji, H.Y.; Gao, J.F.

    1998-01-01

    Intraband E2 transitions of some 30 deformed nuclei are analysed using a generalized Michailov plot, based on an E2 transition formula in the SU(3) limit of the sdg interacting boson model. The general E2 transition formula in the sdg-IBM has an L(L+3) term in addition to the usual SU(3) model result. It is found that the general E2 formula can describe the inband transitions well. Comparisons with other models are made. The implications of the results are also discussed. (author)

  3. Global set of quadrupole deformation parameters for even-even nuclei

    International Nuclear Information System (INIS)

    Raman, S.; Nestor, C.W. Jr.

    1986-01-01

    A compilation of experimental results has been completed for the reduced electric quadrupole transition probability [B(E2)up arrow] between the 0 + ground state and the first 2 + state in even-even nuclei. This compilation together with certain simple relationships noted by other authors can be used to make reasonable predictions of unmeasured B(E2)up arrow values. The quadrupole deformation parameter β 2 immediately follows, because β 2 is proportional to [B(E2)up arrow]/sup 1/2/. 8 refs., 7 figs

  4. Evolution of the low-lying dipole strength in deformed nuclei with extreme neutron excess with the Relativistic QRPA

    International Nuclear Information System (INIS)

    Pena Arteaga, D.; Khan, E.; Ring, P.

    2009-01-01

    Covariant density functional theory, in the framework of self-consistent Relativistic Hartree Bogoliubov (HFB) and Relativistic Quasiparticle Random Phase approximation (RQRPA), is for the first time applied to axially deformed nuclei [1]. The fully self-consistent RHB+RQRPA equations are posed for the case of axial symmetry and different energy functionals, and solved with the help of a new parallel code. As a sample application, the El strength is systematically analyzed in very neutron-rich Sn nuclei, beyond 1 32S n until 1 66S n [2]. The great neutron excess favors the appearance of a deformed ground state for 1 42-162S n. The evolution of the low-lying strength in deformed nuclei is discussed, and in particular its dependence on the interplay of two major and competing factors, isospin asymmetry and deformation.(author)

  5. Research on manufacturing aluminum - rare earth alloy with a high content of rare earth (> 20% RE) from total rare earth oxides by thermit reduction

    International Nuclear Information System (INIS)

    Ngo Trong Hiep; Dam Van Tien; Tran Duy Hai; Ngo Xuan Hung and Ly Thanh Vu

    2004-01-01

    In this report, several theoretical principles of thermit reduction method used for metal oxides to obtain metals, ferroalloys and ligatua with technical purity are presented. Manufacture of aluminum-rare earth alloys by thermit reduction is also described in the report. Data that are generalized based on thermo-kinetic calculation of the thermit reduction and selection of technological flow-sheet based on thermal effect will partly clarify research results in investigating typical features of the process and identify measures to reduce metal loss in discharged slags. (author)

  6. Woods-Saxon potential parametrization at large deformations for odd-plutonium nuclei

    International Nuclear Information System (INIS)

    Garcia, F.; Yoneama, M.L.; Arruda Neto, J.D.T.; Mesa, J.; Bringas, F.; Dias, J.F.; Likhachev, V.P.

    1997-01-01

    The structure of the the single-particle levels in the secondary minima of 237,239,241 Pu fissioning nuclei is analysed with the help of an axially-deformed Woods-Saxon potential. The nuclear shape was parametrized in terms of the Cassinian ovaloids. The parametrization of the spin-orbit part of the potential in the region corresponding to large deformations (second minimum), which depends only on the nuclear surface area, B s , was obtained. With this relation we were able to reproduce successfully the spin (parity) and the energies of the rotational band built on the 8μs isomeric rate in 239 Pu and also to make a spin assignment for both isomer states in 237 Pu and 241 Pu. (author)

  7. Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Martini, M., E-mail: martini.marco@gmail.com [Institut d' Astronomie et d' Astrophysique, Université Libre de Bruxelles, CP-226, 1050 Brussels (Belgium); CEA, DAM, DIF, F-91297 Arpajon (France); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Université Libre de Bruxelles, CP-226, 1050 Brussels (Belgium); Péru, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2014-06-15

    In recent years fully consistent quasiparticle random-phase approximation (QRPA) calculations using finite range Gogny force have been performed to study electromagnetic excitations of several axially-symmetric deformed nuclei up to the {sup 238}U. Here we present the extension of this approach to the charge-exchange nuclear excitations (pnQRPA). In particular we focus on the Isobaric Analog and Gamow-Teller resonances. A comparison of the predicted GT strength distribution with existing experimental data is presented. The role of nuclear deformation is shown. Special attention is paid to β-decay half-lives calculations for which experimental data exist and for specific isotone chains of relevance for the r-process nucleosynthesis.

  8. Rare earths: critical elements for various applications and challenges in their separation

    International Nuclear Information System (INIS)

    Singh, D.K.; Chakravartty, J.K.

    2015-01-01

    High purity rare earths oxides, metal and alloys find wide applications in high tech area such as nuclear energy, permanent magnets, materials for storing hydrogen, phosphors, laser, etc. Rare earths consists a group of 15 elements from La to Lu in the periodic table and it also includes Sc and Y. Due to similar chemical nature owing to common oxidation state of +3, rare earths are very difficult to separate from each other. They have very low separation factors with acidic extractants like D2EHPA and EHEHPA and hence require large number of stages in various cascade of extraction process. Monazite (a source of rare earths, thorium and uranium) is processed at IREL to separate rare earths from thorium and uranium. The rare earths are fractionated into three groups namely light rare earths (LRE), middle rare earths (MRE) and heavy rare earths (HRE) by solvent extraction method employing EHEHPA as extractant

  9. An optical potential for the statically deformed actinide nuclei derived from a global spherical potential

    Science.gov (United States)

    Al-Rawashdeh, S. M.; Jaghoub, M. I.

    2018-04-01

    In this work we test the hypothesis that a properly deformed spherical optical potential, used within a channel-coupling scheme, provides a good description for the scattering data corresponding to neutron induced reactions on the heavy, statically deformed actinides and other lighter deformed nuclei. To accomplish our goal, we have deformed the Koning-Delaroche spherical global potential and then used it in a channel-coupling scheme. The ground-state is coupled to a sufficient number of inelastic rotational channels belonging to the ground-state band to ensure convergence. The predicted total cross sections, elastic and inelastic angular distributions are in good agreement with the experimental data. As a further test, we compare our results to those obtained by a global channel-coupled optical model whose parameters were obtained by fitting elastic and inelastic angular distributions in addition to total cross sections. Our results compare quite well with those obtained by the fitted, channel-coupled optical model. Below neutron incident energies of about 1MeV, our results show that scattering into the rotational excited states of the ground-state band plays a significant role in the scattering process and must be explicitly accounted for using a channel-coupling scheme.

  10. Shape of 44Ar: Onset of deformation in neutron-rich nuclei near 48Ca

    International Nuclear Information System (INIS)

    Zielinska, M.; Goergen, A.; Clement, E.; Korten, W.; Dossat, C.; Ljungvall, J.; Obertelli, A.; Theisen, Ch.; Delaroche, J.-P.; Girod, M.; Buerger, A.; Catford, W.; Iwanicki, J.; Napiorkowski, P. J.; Srebrny, J.; Wrzosek, K.; Libert, J.; PiePtak, D.; Rodriguez-Guzman, R.; Sletten, G.

    2009-01-01

    The development of deformation and shape coexistence in the vicinity of doubly magic 48 Ca, related to the weakening of the N=28 shell closure, was addressed in a low-energy Coulomb excitation experiment using a radioactive 44 Ar beam from the SPIRAL facility at GANIL. The 2 1 + and 2 2 + states in 44 Ar were excited on 208 Pb and 109 Ag targets at two different beam energies. B(E2) values between all observed states and the spectroscopic quadrupole moment of the 2 1 + state were extracted from the differential Coulomb excitation cross sections, indicating a prolate shape of the 44 Ar nucleus and giving evidence of an onset of deformation already two protons and two neutrons away from doubly magic 48 Ca. New Hartree-Fock-Bogoliubov based configuration mixing calculations have been performed with the Gogny D1S interaction for 44 Ar and neighboring nuclei using two different approaches: the angular momentum projected generator coordinate method considering axial quadrupole deformations and a five-dimensional approach including the triaxial degree of freedom. The experimental values and new calculations are furthermore compared to shell-model calculations and to relativistic mean-field calculations. The new results give insight into the weakening of the N=28 shell closure and the development of deformation in this neutron-rich region of the nuclear chart.

  11. Charge ordering in the rare earth manganates: the experimental situation

    International Nuclear Information System (INIS)

    Rao, C.N.R.; Cheetham, A.K.; Raveau, Bernard

    2000-01-01

    Charge-ordered phases of rare earth manganates are novel manifestations arising from interactions between the charge carriers and phonons, giving rise to the localization of carriers at specific sites in the lattice below a certain temperature. Accompanying this phenomenon, the Mn 3+ (e g ) orbitals and the associated lattice distortions also exhibit long range ordering (orbital ordering). What makes the manganates even more interesting is the occurrence of complex spin ordering related to anisotropic magnetic interactions. In this article, we discuss the emerging scenario of charge-ordered rare earth manganates in the light of specific case studies and highlight some of the new experimental findings related to spin, orbital and charge ordering. We also examine features such as the charge stripes and phase separation found experimentally in these materials, and discuss the factors that affect charge-ordering such as the size of A-site cations and magnetic and electric fields, as well as isotopic and chemical substitutions. (author)

  12. Spectroscopic identification of rare earth elements in phosphate glass

    Science.gov (United States)

    Devangad, Praveen; Tamboli, Maktum; Muhammed Shameem, K. M.; Nayak, Rajesh; Patil, Ajeetkumar; Unnikrishnan, V. K.; Santhosh, C.; Kumar, G. A.

    2018-01-01

    In this work, rare earth-doped phosphate glasses were synthesized and characterized using three different spectroscopic techniques. The absorption spectra of the prepared praseodymium (Pr) and samarium (Sm) doped glasses, recorded by a UV-VIS-NIR spectrophotometer, show the characteristic absorption bands of these elements. To confirm this inference, laser-induced fluorescence spectra of Pr and Sm were obtained at a laser excitation of 442 nm. Their emission bands are reported here. The elemental analysis of these samples was carried out using a laser-induced breakdown spectroscopy (LIBS) system. Characteristic emission lines of Pr and Sm have been identified and reported by the recorded LIBS spectra of glass samples. Results prove that using these three complimentary spectroscopic techniques (absorption, fluorescence and LIBS), we can meaningfully characterize rare earth-doped glass samples.

  13. Exchange interactions in two-state systems: rare earth pyrochlores

    Science.gov (United States)

    Curnoe, S. H.

    2018-06-01

    The general form of the nearest neighbour exchange interaction for rare earth pyrochlores is derived based on symmetry. Generally, the rare earth angular momentum degeneracy is lifted by the crystal electric field (CEF) into singlets and doublets. When the CEF ground state is a doublet that is well-separated from the first excited state the CEF ground state doublet can be treated as a pseudo-spin of some kind. The general form of the nearest neighbour exchange interaction for pseudo-spins on the pyrochlore lattice is derived for three different types of pseudo-spins. The methodology presented in this paper can be applied to other two-state spin systems with a high space group symmetry.

  14. Adducts of rare earth tris-acetylacetonates with dimethyl sulfoxide

    International Nuclear Information System (INIS)

    Dzyubenko, N.G.; Kalenichenko, Yu.V.; Martynenko, L.I.

    1988-01-01

    Adducts of rare earth and yttrium (r.e.e., M) acetylacetonates with dimethyl sulfoxide (DMSO), MA 3 xnDMSO are synthesized. The acetylacetonates of light r.e.e. (M=La-Tb) are shown by different physico-chemical methods to form diadducts of the MA 3 x2DMSOxH 2 O composition, where A - -acetylacetonate-ion, and the acetyl-acetonates of heavy r.e.e. (M=Dy-Lu, Y)-monoadducts MA 3 xDMSO. The estimation of adduct thermal stability is carried out using the values of seeming activation energy of their thermal degradation. Monoadducts are shown to give volatile forms of rare earth acetylacetonates during heating in vacuum, and diadducts do not form volatile forms of acetylacetonates

  15. A divalent rare earth oxide semiconductor: Yttrium monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Kaminaga, Kenichi; Sei, Ryosuke [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan); Department of Chemistry, Tohoku University, Sendai 980-8578 (Japan); Hayashi, Kouichi [Department of Environmental and Materials Engineering, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Happo, Naohisa [School of Information Sciences, Hiroshima City University, Hiroshima 731-3194 (Japan); Tajiri, Hiroo [Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, Sayo 679-5198 (Japan); Oka, Daichi; Fukumura, Tomoteru, E-mail: tomoteru.fukumura.e4@tohoku.ac.jp [Department of Chemistry, Tohoku University, Sendai 980-8578 (Japan); Hasegawa, Tetsuya [Department of Chemistry, The University of Tokyo, Tokyo 113-0033 (Japan)

    2016-03-21

    Rare earth oxides are usually widegap insulators like Y{sub 2}O{sub 3} with closed shell trivalent rare earth ions. In this study, solid phase rock salt structure yttrium monoxide, YO, with unusual valence of Y{sup 2+} (4d{sup 1}) was synthesized in a form of epitaxial thin film by pulsed laser deposition method. YO has been recognized as gaseous phase in previous studies. In contrast with Y{sub 2}O{sub 3}, YO was dark-brown colored and narrow gap semiconductor. The tunable electrical conductivity ranging from 10{sup −1} to 10{sup 3} Ω{sup −1 }cm{sup −1} was attributed to the presence of oxygen vacancies serving as electron donor. Weak antilocalization behavior observed in magnetoresistance indicated significant role of spin-orbit coupling as a manifestation of 4d electron carrier.

  16. Magnetomigration of rare-earth ions in inhomogeneous magnetic fields.

    Science.gov (United States)

    Franczak, Agnieszka; Binnemans, Koen; Jan Fransaer

    2016-10-05

    The effects of external inhomogenous (gradient) magnetic fields on the movement of the rare-earth ions: Dy 3+ , Gd 3+ and Y 3+ , in initially homogeneous aqueous solutions have been investigated. Differences in the migration of rare-earth ions in gradient magnetic fields were observed, depending on the magnetic character of the ions: paramagnetic ions of Dy 3+ and Gd 3+ move towards regions of the sample where the magnetic field gradient is the strongest, while diamagnetic ions of Y 3+ move in the opposite direction. It has been showed that the low magnetic field gradients, such the ones generated by permanent magnets, are sufficient to observe the magnetomigration effects of the ions in solution. The present work clearly establishes the behavior of magnetically different ions in initially homogeneous aqueous solutions exposed to magnetic field gradients. To this avail, a methodology for measuring the local concentration differences of metal ions in liquid samples was developed.

  17. Field-induced valence transition in rare-earth system

    International Nuclear Information System (INIS)

    Chattopadhaya, A.; Ghatak, S.K.

    2000-01-01

    The magnetic field-induced valence transition in rare-earth compound has been examined based on a pseudospin S=1 Ising model proposed earlier for valence transition. The model includes finite mixing between two pertinent ionic configurations (magnetic and non-magnetic) separated by an energy gap and with intersite interaction between rare-earth ions. Using the mean field approximation the magnetic behaviour and the critical field (H c ) for transition are obtained as a function of energy gap and temperature. The phase boundary defined in terms of reduced field H c /H co and reduced temperature T/T v (T v being valence transition temperature in absence of field) is nearly independent of energy gap. These results are in qualitative agreement with experimental observation in Yb- and Eu-compounds

  18. Rare-earth magnet ingestion: a childhood danger reaches adolescence.

    Science.gov (United States)

    Agha, Beesan Shalabi; Sturm, Jesse J; Costello, Brian E

    2013-10-01

    Ingestion of multiple magnets may cause serious gastrointestinal morbidity, such as pressure necrosis, perforation, fistula formation, or intestinal obstruction due to forceful attraction across bowel wall. Although the consequences of multiple magnet ingestion are well documented in young children, the current popularity of small, powerful rare-earth magnets marketed as "desk toys" has heightened this safety concern in all pediatric age groups. A recent US Consumer Product Safety Commission product-wide warning additionally reports the adolescent practice of using toy high-powered, ball-bearing magnets to simulate tongue and lip piercings, a behavior that may increase risk of inadvertent ingestion. We describe 2 cases of older children (male; aged 10 and 13 years, respectively) with unintentional ingestion of multiple rare-earth magnets. Health care providers should be alerted to the potential for misuse of these high-powered, ball-bearing magnets among older children and adolescents.

  19. The occurrence of rare earth elements in some Finnish mires

    Directory of Open Access Journals (Sweden)

    Yliruokanen, I.

    1995-12-01

    Full Text Available The content of the more abundant rare earths (RE (Y, La, Ce, Pr, Nd and Sm in the ash of 399 peat samples from 26 Finnish mires was determined by X-ray fluorescence spectrometry. The content of all rare earths (La-Lu, Y in 29 samples was also determined by spark source mass spectrometry. The median RE contents in peat ashes from areas where the bedrock consists of rapakivi granite, granite or archean gneiss are reported. Detailed data concerning the individual mires are also presented. The highest RE contents were found in samples from rapakivi granite areas where a strong negative Eu anomaly was also observed. The RE contents were in general highest at the basal peat layers.

  20. γ-spectroscopy and radioactive beams: search for highly deformed exotic nuclei

    International Nuclear Information System (INIS)

    Rosse, B.

    2006-07-01

    This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A ∼ 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr 76 radioactive beam (T1/2 = 14.8 h). γ-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first γ transition was observed in the very exotic odd-odd Pm 130 nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)

  1. γ-spectroscopy and radioactive beams: search for highly deformed exotic nuclei

    International Nuclear Information System (INIS)

    Rosse, Bertrand

    2006-01-01

    This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A∼130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient 76 Kr radioactive beam (T 1/2 = 14.8 h). γ-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first γ transition was observed in the very exotic odd-odd 130 Pm nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)

  2. On solubility of rare earth chlorides in water at different temperatures

    International Nuclear Information System (INIS)

    Nikolaev, A.V.; Sorokina, A.A.; Sokolova, N.P.; Kotlyar-Shapirov, G.S.; Bagryantseva, L.I.

    1978-01-01

    Solubility of rare earth chlorides at -5, -10 and -15 deg C is studied. Rare earth chloride solubility dependences on the temperature in the interval from -15 to 50 deg C are presented. Decrease of solubility temperature coefficient to a zero is observed at temperature drop almost for all rare earth chlorides. Solubility temperature coefficient at the same temperature but for different rare earth chlorides reduces appreciably with the growth of rare earth chloride serial number. This testifies to the corresponding decrease of integral solution heat of rare earth chloride crystallohydrates

  3. Fragmentation of two-phonon {gamma}-vibrational strength in deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C.Y.; Cline, D. [Univ. of Rochester, NY (United States)

    1996-12-31

    Rotational and vibrational modes of collective motion. are very useful in classifying the low-lying excited states in deformed nuclei. The rotational mode of collective motion is characterized by rotational bands having correlated level energies and strongly-enhanced E2 matrix elements. The lowest intrinsic excitation with I,K{sup {pi}} = 2,2{sup +} in even-even deformed nuclei, typically occurring at {approx}1 MeV, is classified as a one-phonon {gamma}-vibration state. In a pure harmonic vibration limit, the expected two-phonon {gamma}-vibration states with I,K{sup {pi}} = 0,0{sup +} and 4,4{sup +} should have excitation energies at twice that of the I,K{sup {pi}} = 2,2{sup +} excitation, i.e. {approx}2 MeV, which usually is above the pairing gap leading to possible mixing with two-quasiparticle configurations. Therefore, the question of the localization of two-phonon {gamma}-vibration strength has been raised because mixing may lead to fragmentation of the two-phonon strength over a range of excitation energy. For several well-deformed nuclei, an assignment of I,K{sup {pi}}=4,4{sup +} states as being two-phonon vibrational excitations has been suggested based on the excitation energies and the predominant {gamma}-ray decay to the I,K{sup {pi}}=2,2{sup +} state. However, absolute B(E2) values connecting the presumed two- and one-phonon states are the only unambiguous measure of double phonon excitation. Such B(E2) data are available for {sup 156}Gd, {sup 160}Dy, {sup 168}Er, {sup 232}Th, and {sup 186,188,190,192}Os. Except for {sup 160}Dy, the measured B(E2) values range from 2-3 Weisskopf units in {sup 156}Gd to 10-20 Weisskopf units in osmium nuclei; enhancement that is consistent with collective modes of motion.

  4. Electron states in thulium and other rare-earth metals

    International Nuclear Information System (INIS)

    Strange, P.; Fairbairn, W.M.; Lee, P.M.

    1983-01-01

    The LMTO method has been applied to calculate band structures for the heavier rare-earth metals. The calculations are relativistic. Thulium in particular has been considered, where a frozen core approximation is used, and the outer electrons are treated selfconsistently. Problems associated with the localisation and interactions of the 4f electrons are discussed. Teh comparisons between experimental data and calculated quantities are encouraging, but more data on high-purity single crystals would be helpful. (author)

  5. THE EFFECTS OF RARE EARTHS ON ACTIVITY AND SURFACE ...

    African Journals Online (AJOL)

    A series of Ru-RE/γ-AL2O3 (RE = Ce, Pr, La, Sm, Tb or Gd) and Ru/γ-AL2O3 catalysts were prepared by impregnation method. The influence of rare earths on the catalytic performance of Ru/γ-AL2O3 catalyst for the water gas shift reaction was studied. The catalysts were characterized by X-ray diffraction (XRD), ...

  6. China’s Rare Earth Policies: Economic Statecraft or Interdependence?

    Science.gov (United States)

    2012-12-01

    to China.112 In September 2011, Toyota announced that it was planning to manufacture components (such as electric motors and batteries) for its...Export Regime: Economic and Trade Implications for the United States,” Congressional Research Service, April 30, 2012, 19. 113 BBC, “ Toyota to...SOEs to influence rare earth prices and affect the position of its competitors including the small domestic mining firms. Under this new consolidation

  7. Vibrational spectra of double rare earth alkaline metal metaphosphates

    International Nuclear Information System (INIS)

    Madij, V.A.; Krasilov, Yu.I.; Kizel', V.A.; Denisov, Yu.V.; Chudinova, N.N.; Vinogradova, N.V.

    1978-01-01

    Joint analysis of the Raman and infrared absorption spectra, as well as X-ray structural data for binary metaphosphates, suggest a cyclic structure of the anion in RbEu(PO 3 ) 4 and a chain structure of the anions in HEu(PO 3 ) 4 and LiEu(PO 3 ) 4 . Spectroscopic criteria are proposed for distinguishing between cyclic and chain structures in binary metaphosphates of rare earth elements and alkali metals

  8. X-ray dichroism of rare earth materials

    International Nuclear Information System (INIS)

    Goedkoop, J.B.

    1989-01-01

    The theme of this thesis is the investigation of the strong polarization dependende, or dichroism, that occur in the X-ray absorption spectra of rare earth materials. The rare earth elements distinguish themselves from the other elements through the behaviour of the 4f electrons which form the valence shell. This shell lies deep inside the atom, with the result that influences from the surrounding solid are well screened off by the outer electrons, so that even in the solid the 4f shell behaves very much like a in free atom or ion, and is almost completely spherically symmetric. Perturbations from the solid environment however always disturb this symmetry to some extend, with the result that the absorption spectrum becomes dependent on the mutual orientation of the polarization vector of the radiation and the ion. Earlier the existence of a strong magnetic X-ray dichroism (MXD) in the 3d→4f transitions of rare earths. In this thesis this work is extended, to a small degree theoretically but mainly experimentally. MXD is used in experiments on bulk sample, terbium iron garnet, and on rare earth overlayers on a ferromagnetic surface, Ni(110). The results of the latter study show unequivocally the potential of the MXD technique. The second theme of the thesis concerns experimental developments in soft X-ray spectroscopy. A description is given of a double crystal monochromator beamline that was constructed by our group at LURE, France. Results of the use of an organic crystal - multilayer comination in such a monochromator is described. Also a method is described for the characterization of the resolution of soft X-ray monochromators. Finally a contribution to the characterization of the electron yield technique in the soft X-ray range is given. (author). 296 refs.; 64 figs.; 59 schemes; 9 tabs

  9. Nuclear orientation studies of rare-earth metals

    International Nuclear Information System (INIS)

    Krane, K.S.; Morgan, G.L.; Moses, J.D.

    1981-01-01

    The angular distributions of gamma rays from 166 sup(m)Ho and 160 Tb aligned at low temperatures in, respectively, Ho metal and Tb metal have been measured. Large hyperfine splittings, expected for the rare earths, have been deduced from the temperature dependence of the gamma ray anisotropies. Both samples show a macroscopic magnetic anisotropy which is not consistent with an interpretation in terms of a randomly oriented polycrystalline structure. (orig.)

  10. The transfer of rare earth elements through liquid extraction membranes

    International Nuclear Information System (INIS)

    Kapranchik, V.P.; Proyaev, V.V.; Kopyrin, A.A.

    1988-01-01

    The transfer of rare earth elements through liquid extraction membranes, presenting Dacron nuclear filters, impregnated by extractants of different types (tributylphosphine oxide; di-2-ethylhexylphosphoric acid, HDEHP; trioctylamine, TOA) is investigated. It is ascertained that in systems with extractant-carriers TOA and HDEHP inversion of dependences of flow values and distribution coefficients on the element atomic number is observed. Mathematical model of transfer, permitting to establish relation between extractional and transport characteristics of the membrane, is suggested

  11. High coercivity rare earth-transition metal magnets

    International Nuclear Information System (INIS)

    Croat, J.J.

    1982-01-01

    Ferromagnetic compositions having intrinsic magnetic coercivities at room temperature of at least 1,000 Oersteds are formed by the controlled quenching of molten rare earth -transition metal alloys. Hard magnets may be inexpensively formed from the lower atomic weight lanthanide elements and iron. The preferable compositions lie within: at least one of Fe, Ni, Co (20 to 70 atomic percent); and at least one of Ce, Pr, Na, Sm, Eu, Tb, Dy, Ho, Er, Tm, Y (80 to 30 atomic percent). (author)

  12. Random magnetism in amorphous rare-earth alloys (invited)

    Science.gov (United States)

    Sellmyer, D. J.; Nafis, S.

    1985-04-01

    Several aspects of the magnetic transitions seen in rare-earth metallic glasses are discussed, particularly with reference to recent theoretical work. These include: (a) apparent double transitions observed in Gd glasses where exchange fluctuations are important, (b) evidence for a correlated speromagnetic state recently predicted by Chudnovsky and Serota, and (c) the analysis of a Tb glass with strong random anisotropy in terms of an Ising-type spin-glass transition.

  13. Synthesis and study of rare earth complexonates with ethylenediaminedisuccinic acid

    International Nuclear Information System (INIS)

    Mitrofanova, N.D.; Martynenko, L.I.; Kolleganov, M.Yu.

    1986-01-01

    Solid complexonates with ethylenediaminedisuccinic acid of HMZxnH 2 O and KMLxnH 2 O composition are synthesized for the Y, Sc and rare earths. The compounds were studied by different physicochemical methods. According to data on IR and electron spectroscopy the conclusion is made on-COOH-group coordination in protonated HML complexes. The complexes are X-ray amorphous, they have polymeric structure

  14. High coercivity rare earth-transition metal magnets

    International Nuclear Information System (INIS)

    Croat, J.J.

    1982-01-01

    Ferromagnetic compositions having intrinsic magnetic coercivities at room temperature of at least 1,000 Oersteds are formed by the controlled quenching of molten rare earth-transition metal alloys. Hard magnets may be inexpensively formed from the lower atomic weight lanthanide elements and iron. The preferable compositions lie within: at least one of Fe, Ni, Co; 20 - 70 atomic percent: at least one of Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Y; 80 - 30 atomic percent. (author)

  15. Rare Earth Borohydrides—Crystal Structures and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Christoph Frommen

    2017-12-01

    Full Text Available Rare earth (RE borohydrides have received considerable attention during the past ten years as possible hydrogen storage materials due to their relatively high gravimetric hydrogen density. This review illustrates the rich chemistry, structural diversity and thermal properties of borohydrides containing RE elements. In addition, it highlights the decomposition and rehydrogenation properties of composites containing RE-borohydrides, light-weight metal borohydrides such as LiBH4 and additives such as LiH.

  16. Sensing Using Rare-Earth-Doped Upconversion Nanoparticles

    OpenAIRE

    Hao, Shuwei; Chen, Guanying; Yang, Chunhui

    2013-01-01

    Optical sensing plays an important role in theranostics due to its capability to detect hint biochemical entities or molecular targets as well as to precisely monitor specific fundamental psychological processes. Rare-earth (RE) doped upconversion nanoparticles (UCNPs) are promising for these endeavors due to their unique frequency converting capability; they emit efficient and sharp visible or ultraviolet (UV) luminescence via use of ladder-like energy levels of RE ions when excited at near ...

  17. Resonance electronic Raman scattering in rare earth crystals

    International Nuclear Information System (INIS)

    Williams, G.M.

    1988-01-01

    The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce 3+ (4f 1 ) in single crystals of LuPO 4 and Er 3+ (4f 11 ) in single crystals of ErPO 4 . 134 refs., 92 figs., 33 tabs

  18. PIXE methodology of rare earth element analysis and its applications

    International Nuclear Information System (INIS)

    Ma Xinpei

    1992-01-01

    The Proton Induced X-ray Emission (PIXE) methodology of rare earth element (REEs) analysis is discussed, including the significance of REE analysis, the principle of PIXE applied to REE, selection of characteristic X-ray for Lanthanide series elements, deconvolution of highly over lapped PIXE spectrum and minimum detection limit (MDL) of REEs. Some practical applications are presented. And the specialities of PIXE analysis to the high pure REE chemicals are discussed. (author)

  19. Complexing in aqueous solutions of rare earth n-aminobenzoates

    International Nuclear Information System (INIS)

    Efremova, G.I.; Buchkova, R.T.; Lapitskaya, A.V.; Pirkes, S.B.

    1977-01-01

    Complexing in the system ''ion of a rare-earth metal - n-aminobenzoic acid'' has been investigated by the pH-metric method in the pH range of 3.5-5.5. In the La-Eu series, the stability of n-aminobenzoate complexes increases and attains the maximum value in the complex Eu (lg Ksub(st)=2.66). In the Gd-Lu series the stability of the complex particles decreases monotonically

  20. Rare earth elements and oxides in liquid phase epitaxy

    Czech Academy of Sciences Publication Activity Database

    Procházková, Olga; Grym, Jan; Zavadil, Jiří; Kopecká, M.

    2006-01-01

    Roč. 100, č. 8 (2006), s. 640-- ISSN 0009-2770. [Sjezd chemických společností /58./. Ústí nad Labem, 04.09.2006-08.09.2006] R&D Projects: GA ČR(CZ) GA102/06/0153 Institutional research plan: CEZ:AV0Z20670512 Keywords : semiconductor technology * rare earth metals Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.431, year: 2006

  1. Oxygen stabilized rare-earth iron intermetallic compounds

    International Nuclear Information System (INIS)

    Dariel, M.P.; Malekzadeh, M.; Pickus, M.R.

    1975-10-01

    A new, oxygen-stabilized intermetallic compound was identified in sintered, pre-alloyed rare-earth iron powder samples. Its composition corresponds to formula R 12 Fe 32 O 2 and its crystal structure belongs to space group Im3m. The presence of these compounds was observed, so far, in several R--Fe--O systems, with R = Gd, Tb, Dy, Ho, Er, and Y

  2. General geochemical properties and abundances of the rare earth elements

    International Nuclear Information System (INIS)

    Henderson, P.

    1984-01-01

    This chapter reviews some of the fundamental aspects of rare earth elements (REE) geochemistry and gives data on abundances in the solar system, the bulk Earth and the Earth's crust. It describes the state of knowledge on the partitioning of the REE, especially in igneous rock systems, and cites reference works concerned with the REE. Several chemical properties of REE are discussed (oxidation states; redox conditions; element coordination and ionic radii; element substitution). (Auth.)

  3. Rapid Evaluation of Radioactive Contamination in Rare Earth Mine Mining

    Science.gov (United States)

    Wang, N.

    2017-12-01

    In order to estimate the current levels of environmental radioactivity in Bayan Obo rare earth mine and to study the rapid evaluation methods of radioactivity contamination in the rare earth mine, the surveys of the in-situ gamma-ray spectrometry and gamma dose rate measurement were carried out around the mining area and living area. The in-situ gamma-ray spectrometer was composed of a scintillation detector of NaI(Tl) (Φ75mm×75mm) and a multichannel analyzer. Our survey results in Bayan Obo Mine display: (1) Thorium-232 is the radioactive contamination source of this region, and uranium-238 and potassium - 40 is at the background level. (2) The average content of thorium-232 in the slag of the tailings dam in Bayan Obo is as high as 276 mg/kg, which is 37 times as the global average value of thorium content. (3) We found that the thorium-232 content in the soil in the living area near the mining is higher than that in the local soil in Guyang County. The average thorium-232 concentrations in the mining areas of the Bayan Obo Mine and the living areas of the Bayan Obo Town were 18.7±7.5 and 26.2±9.1 mg/kg, respectively. (4) It was observed that thorium-232 was abnormal distributed in the contaminated area near the tailings dam. Our preliminary research results show that the in-situ gamma-ray spectrometry is an effective approach of fast evaluating rare earths radioactive pollution, not only can the scene to determine the types of radioactive contamination source, but also to measure the radioactivity concentration of thorium and uranium in soil. The environmental radioactive evaluation of rare earth ore and tailings dam in open-pit mining is also needed. The research was supported by National Natural Science Foundation of China (No. 41674111).

  4. Rare metal and rare earth pegmatites of Western India

    International Nuclear Information System (INIS)

    Maithani, P.B.; Nagar, R.K.

    1999-01-01

    Rajasthan Mica Belt in western India is one of the three major mica-producing Proterozoic pegmatite belts of India, the others being in Bihar and Andhra Pradesh. The pegmatites of these mica belts, in general, are associated with the rare metal (RM) and rare earth element (REE)-bearing minerals like columbite-tantalite, beryl, lepidolite and other multiple oxides. RM-REE pegmatites of Gujarat are devoid of commercially workable mica. These pegmatites are geologically characterised in this paper, based on their association with granite plutons geochemistry, and RM and REE potential. In addition to RM and RE-bearing pegmatites, granites of the Umedpur area, Gujarat also show anomalous concentration (0.97 wt%) of rare metals (6431 ppm Nb, 1266 ppm Ta, 454 ppm Sn, 173 ppm W), (1098 ppm Ce 1.36% Y 2 O 3 ) rare earths, and uranium (0.40% eU 3 O 8 ). Eluvial concentrations in the soil and panned concentrate (0.04-0.28 wt%) analysed up to 7.4%Nb 2 O 5 , 836 ppm Ta, and 1.31% Y. Discrete columbite-tantalite and betafite have been identified in these concentrates in addition to other minerals like zircon, rutile, sphene and xenotime. This area with discrete RM R EE mineral phases could be significant as a non-pegmatite source for rare metal and rare earths. (author)

  5. Recovery of rare earth minerals, with emphasis on flotation process

    International Nuclear Information System (INIS)

    Houot, R.; Cuif, J.P.; Mottot, Y.; Samama, J.C.

    1991-01-01

    Bastnasite and monazite are the two major minerals used commercially to supply most of the rare earths. Monazite is often a by-product of the concentration of heavy minerals of zirconium and titanium in beach sands. Thus, the methods of concentration are gravity (spirals, Reichert cones and shaking tables), ending with magnetism, electrostatic and in certain cases, flotation. The two main deposits of bastnasite are Mountain Pass (U.S.A.) and Bayan Obo (China). The rock bastnasite content is within 15% and the recovery of rare earth minerals is made through flotation. The flowsheets are complex enough because the existence of accompanying minerals such as quartz, iron components, barite, fluorite, calcite, etc. The conditioning is done by heating and the frequently employed collector is a fatty acid associated with selective agents, as sodium silicate or fluosilicate, lignin sulphonate, sodium carbonate, aluminium salts, etc. Recent studies tempt to introduce the use of phosphoric esters, dicarboxilic, sulphonic and/or sulphosuccinic acids. Concentrates with 60% REO are then treated with acidic solution to eliminate residual calcite. The possibility of obtaining products enriched with rare earths are also noted: these are ores of uranium (Elliot Lake), pyrochlore, apatite, and other complex ores with euxenite, fergusonite or loparite. (author) 10 figs., 6 tabs., 57 refs

  6. Binding of rare earths to serum proteins and DNA

    International Nuclear Information System (INIS)

    Rosoff, B.; Spencer, H.

    1979-01-01

    In order to investigate further the physiological behavior of rare earths and rare earth chelates, studies of the binding of 46 Sc, 91 Y, and 140 La to serum proteins and to nucleic acids were performed using the methods of equilibrium dialysis and ultrafiltration. The binding of lanthanum and yttrium as the chlorides to α-globulin increased as the free rare earth concentration increased. When scandium and lanthanum were chelated in nitrilotriacetate (NTA) the binding to α-globulin was considerably less and there was no binding to albumin. The binding of 46 Sc chelated to ethylenediamine di(O-hydroxyphenylacetate) (EDDHA) was five times greater than of 46 Sc chloride. When the free scandium concentration was increased, the moles bound per mole of protein increased proportionally and the binding was reversible. Scandium was 100% filterable from a mixture of human serum and from the scandium chelates with high stability constants scandium diethylenetriaminepentaacetate (ScDTPA), scandium ethylenediaminetetraacetate (ScEDTA) and scandium cyclohexane trans-1,2-diaminetetraacetate (ScCDTA) respectively. In contrast, only 2% of the scandium was filterable when scandium nitrilotriacetate, a scandium chelate of low stability constant, was used. (Auth.)

  7. Restoration of rare earth mine areas: organic amendments and phytoremediation.

    Science.gov (United States)

    Zhou, Lingyan; Li, Zhaolong; Liu, Wen; Liu, Shenghong; Zhang, Limin; Zhong, Liyan; Luo, Ximei; Liang, Hong

    2015-11-01

    Overexploitation of rare earth mine has caused serious desertification and various environmental issues, and ecological restoration of a mining area is an important concern in China. In this study, experiments involving dry grass landfilling, chicken manure broadcasting, and plant cultivation were carried out to reclaim a rare earth mine area located in Heping County, Guangdong Province, China. The prime focus was to improve soil quality in terms of nutrients, microbial community, enzyme activity, and physicochemical properties so as to reclaim the land. After 2 years of restoration, an increase of organic matter (OM), available potassium (K), available phosphorus (P) levels, and acid phosphatase (ACP) activity and a reduction of the available nitrogen (N) level and urease (URE) activity in soil were achieved compared to the original mined land. The nutrients and enzyme activities in soil with 5 years of restoration were close to or surpass those in the unexploited land as control. The bulk density, total porosity, water holding capacity, pH, and electrical conductivity (EC) of soil were improved, and the number of cultivable microorganisms and the bacterial diversity in soil were greatly increased with time during ecological restoration, especially for surface soil. Furthermore, the artificial vegetation stably grew at the restored mining sites. The results indicated that organic amendments and phytoremediation could ecologically restore the rare earth mining sites and the mined land could finally be planted as farmland.

  8. Mimicking the magnetic properties of rare earth elements using superatoms.

    Science.gov (United States)

    Cheng, Shi-Bo; Berkdemir, Cuneyt; Castleman, A W

    2015-04-21

    Rare earth elements (REs) consist of a very important group in the periodic table that is vital to many modern technologies. The mining process, however, is extremely damaging to the environment, making them low yield and very expensive. Therefore, mimicking the properties of REs in a superatom framework is especially valuable but at the same time, technically challenging and requiring advanced concepts about manipulating properties of atom/molecular complexes. Herein, by using photoelectron imaging spectroscopy, we provide original idea and direct experimental evidence that chosen boron-doped clusters could mimic the magnetic characteristics of REs. Specifically, the neutral LaB and NdB clusters are found to have similar unpaired electrons and magnetic moments as their isovalent REs (namely Nd and Eu, respectively), opening up the great possibility in accomplishing rare earth mimicry. Extension of the superatom concept into the rare earth group not only further shows the power and advance of this concept but also, will stimulate more efforts to explore new superatomic clusters to mimic the chemistry of these heavy atoms, which will be of great importance in designing novel building blocks in the application of cluster-assembled nanomaterials. Additionally, based on these experimental findings, a novel "magic boron" counting rule is proposed to estimate the numbers of unpaired electrons in diatomic LnB clusters.

  9. Correlations in rare-earth transition-metal permanent magnets

    International Nuclear Information System (INIS)

    Skomski, R.; Manchanda, P.; Kashyap, A.

    2015-01-01

    It is investigated how electron-electron correlations affect the intrinsic properties of rare-earth transition-metal magnets. Focusing on orbital moment and anisotropy, we perform model calculations for 3d-4f alloys and density-functional theory (DFT) calculations for NdCo 5 . On an independent-electron level, the use of a single Slater determinant with broken spin symmetry introduces Hund's rule correlations, which govern the behavior of rare-earth ions and of alloys described by the local spin density approximation (LSDA) and LSDA + U approximations to DFT. By contrast, rare-earth ions in intermetallics involve configuration interactions between two or more Slater determinants and lead to phenomena such as spin-charge distribution. Analyzing DFT as a Legendre transformation and using Bethe's crystal-field theory, we show that the corresponding density functionals are very different from familiar LSDA-type expressions and outline the effect of spin-charge separation on the magnetocrystalline anisotropy

  10. Correlations in rare-earth transition-metal permanent magnets

    Science.gov (United States)

    Skomski, R.; Manchanda, P.; Kashyap, A.

    2015-05-01

    It is investigated how electron-electron correlations affect the intrinsic properties of rare-earth transition-metal magnets. Focusing on orbital moment and anisotropy, we perform model calculations for 3d-4f alloys and density-functional theory (DFT) calculations for NdCo5. On an independent-electron level, the use of a single Slater determinant with broken spin symmetry introduces Hund's rule correlations, which govern the behavior of rare-earth ions and of alloys described by the local spin density approximation (LSDA) and LSDA + U approximations to DFT. By contrast, rare-earth ions in intermetallics involve configuration interactions between two or more Slater determinants and lead to phenomena such as spin-charge distribution. Analyzing DFT as a Legendre transformation and using Bethe's crystal-field theory, we show that the corresponding density functionals are very different from familiar LSDA-type expressions and outline the effect of spin-charge separation on the magnetocrystalline anisotropy.

  11. Development of rare earth regenerator materials in fine wire form

    International Nuclear Information System (INIS)

    Wong, T.; Seuntjens, J.M.

    1997-01-01

    The use of rare earth metals, both in the pure and alloyed state, have been examined for use as regenerators in cryocooler applications and as the working material in active magnetic refrigerators. In both applications there is a requirement for the rare earth material to have a constant and uniform cross section, an average size on the order of 50-200 microns in diameter, and low levels of impurities. Existing powder production methods have drawbacks such as oxygen contamination, non-uniform size, inconsistent cross sections, and low production yields. A novel approach for the production of rare earth metals and alloys in fine wire form has been developed. This is accomplished by assembling a copperjacket and niobium barrier around a RE ingot, extruding the assembly, and reducing it with standard wire drawing practices. Strand anneals are utilized between drawing passes when necessary in order to recrystallize the RE core and restore ductility. The copperjacket is removed by chemical means at final size, leaving the Nb barrier in place as a protective coating. This process has been applied to gadolinium, dysprosium and a GdDy alloy

  12. Social and Environmental Impact of the Rare Earth Industries

    Directory of Open Access Journals (Sweden)

    Saleem H. Ali

    2014-02-01

    Full Text Available The use of rare earth elements in various technologies continues to grow despite some alternatives being found for particular uses. Given a history of ecological concerns about pollution from rare earth mines, particularly in China, there are growing social and environmental concerns about the growth of the mining and mineral processing in this sector. This is best exemplified by the recent social and environmental conflict surrounding the development of the Lynas Advanced Materials Plant (LAMP in Kuantan, Malaysia which led to international activism and claims of environmental and social injustice. This paper analyses the structure of environmental and social conflicts surrounding rare earth minerals and opportunities for improving the social and environmental performance of the sector. Many of these elements are used for green technologies. Opportunities exist that offer a more circular supply chain following industrial ecological principles through which reuse and recycling of the materials can provide a means of mitigating social and environmental conflicts in this sector. In addition, public engagement processes that recognize community concerns about radiation, and transparent scientifically predicated decision-making through an appropriate governance structure within regulatory organizations are also presented.

  13. Structural, magnetic and electronic properties of rare earth ternary oxides Li Ln(II) 2 Ln(III)O4

    International Nuclear Information System (INIS)

    Malki, M.

    1987-06-01

    Properties of a new class of rare earth ternary oxides Li Ln(II) 2 Ln(III)O 4 where Ln(II) is a divalent metal (Sr, Eu) and Ln(III) a trivalent rare earth (Eu, Gd, Dy, Er and Y). These orthorhombic compounds (type Li Eu 3 O 4 ) allow the study of many magnetic phenomena and their evolution in function of the nature of Ln(II) and Ln(III): diamagnetic ions Sr 2+ , Y 3+ ; isotrope magnetic ions: Eu 2+ , Gd 3+ and anisotrope magnetic ions Dy 3+ , Er 3+ . Magnetic and electric properties are obtained by classical techniques and from hyperfine interaction by Moessbauer spectroscopy. The possibility to use several Moessbauer resonance (nuclei Eu 151, Gd 155, Dy 161 and Er 166) completes informations obtained by the macroscopic study [fr

  14. Novel precursors for the deposition of rare earth oxides

    International Nuclear Information System (INIS)

    Ahlers, Mareike

    2010-01-01

    During this work rare earth solvates with nitrate and perchlorate anions have been investigated. All compounds have been structurally characterized and analyzed using thermal gravimetric analysis. The decomposition residues were analyzed using powder diffraction methods. Almost all compounds showed a characteristically intense exothermic decomposition step during the thermal decomposition, most likely caused by an intramolecular redox reaction between the nitrate or perchlorate anion respectively and the organic solvent molecules. The nitrates RE(NO 3 ) 3 (CH(OCH 3 ) 3 ) 2 (RE = Sm, Eu) were isolated and characterized for the first time as the intermediate of the dehydration reaction with trimethyl orthoformate. The known compound group of dimethoxyethane solvates was then expanded with RE(NO 3 ) 3 (O 2 C 4 H 10 ) (RE = La, Sm, Eu). Considering the possible use as precursor material the already described neodymium compound is also discussed. The thermal decomposition of these compounds yields the respective cubic rare earth oxide and shows the typical intense exothermic decomposition reaction. A variety of different precursor system based on nitrate solvates for the deposition of rare earth oxide layers on a silicon surface was developed and investigated in collaboration with the group of Prof. Dr. Al-Shamery (Univ. Oldenburg). Ultra thin films on a H-Si(111) surface were obtained via the deposition of the precursor, which was dissolved in organic solvents. An oxide layer was detected after the heating of the sample. The film thickness was measured as < 10 nm, whereas the thickness of the film was controlled by the concentration of the precursor solution. Sm(ClO 4 ) 3 (CH(OCH 3 ) 3 ) 3 was isolated and characterized for the first time as the intermediate of the dehydration reaction with trimethyl orthoformate. Eu(ClO 4 ) 3 (CH(OCH 3 ) 3 ) 2 (MeOH) 2 was obtained without recrystallization. The methanol molecules, formed during the hydrolysis of the trimethyl

  15. Production of rare earth polishing powders in Russia

    International Nuclear Information System (INIS)

    Kosynkin, V.D.; Ivanov, E.N.; Kotrekhov, V.A.; Shtutza, M.G.; Grabko, A.I.

    1998-01-01

    Full text: Russia is a potent producer of polishing powders made of rare earth material presented as an extensive and well developed base. Considering the reserves, the facilities predisposition and the polishing agent (cerium dioxide) content the chief mineral source is loparite, apatite and monazite. The production of rare earth polishing powders is based on specially developed continuous technological processes, corrosion-proof equipment, ensuring a high and stable production quality. A special attention is paid to the radiation safety of the powders. The initial material for the rare earth polishing powders based on loparite is the fusion cake of rare earth chlorides obtained at that mineral chlorination. The technology of the polishing powder production from the REE fusion cake includes the following stages: dissolution of the REE fusion cake chlorides; - thorough cleaning of the REE fusion cake chlorides from radioactive and non-rare-earth impurities; chemical precipitation of REE carbonates, obtaining middlings with proper material and granulometric composition, thermal treatment of precipitated carbonates followed with the operations of drying and roasting; classification of roasted oxides, obtaining end products - polishing powders. The production of fluorine-containing powders includes the stage of their fluorination after the stage of carbonate precipitation. The stabilizing doping can be introduced both into the middlings during one of the technological process of powders manufacturing and into the end product. Rare earth polishing powders are manufactured in Russia by the Share Holding Company 'Chepetz Mechanical Plant' (ChMP Co.), the city of Glasov. The plant produces a number of polishing materials, such as; polishing powder Optinol, containing at least 50% by mass of cerium dioxide, used in the mass production of optical and other articles; polishing powder Optinol-10 with doping to improve the sedimentary and aggregate stability of the solid phase

  16. Crystal Fields in Dilute Rare-Earth Metals Obtained from Magnetization Measurements on Dilute Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Touborg, P.; Høg, J.

    1974-01-01

    Crystal field parameters of Tb, Dy, and Er in Sc, Y, and Lu are summarized. These parameters are obtained from magnetization measurements on dilute single crystals, and successfully checked by a number of different methods. The crystal field parameters vary unpredictably with the rare-earth solute....... B40, B60, and B66 are similar in Y and Lu. Crystal field parameters for the pure metals Tb, Dy, and Er are estimated from the crystal fields in Y and Lu....

  17. Chemical separation and ICP-AES determination of rare earths in Al2O3 matrix

    International Nuclear Information System (INIS)

    Argekar, A.A.; Kulkarni, M.J.; Page, A.G.; Manchanda, V.K.

    2005-01-01

    A chemical separation-ICP-AES method has been developed for determination of rare earths in alumina matrix. The quantitative separation of rare earths has also been confirmed using radiotracers. (author)

  18. Geochemistry of rare earths in main media of clay formation and sedimentation

    International Nuclear Information System (INIS)

    Bonnot-Courtois, C.

    1981-01-01

    This work aims i) at a better knowledge of rare earth behavior in surface conditions and ii) possible use of rare earth as a marker for argilaceous mineral genesis. Chemical properties of rare earths and geochemistry of these elements in main rocks are recalled. Rare earth behaviour during continental alteration process, experimental hydrolysis of various magmatic materials and rare earth geochemistry in argilaceous minerals in continental shelf are examined. Then some aspects of rare earth behaviour in oceans are studied: alteration of sea bed and hydrothermalism rare earth distribution in pelagic sediments red clays of deep seas and manganese nodules. In conclusion rare earth behaviour in sedimentary processes of the exogenous cycle is summarized [fr

  19. Description of low-lying vibrational Kπ ≠ 0+ states of deformed nuclei in the quasiparticle-phonon nuclear model

    International Nuclear Information System (INIS)

    Solov'ev, V.G.; Shirikova, N.Yu.

    1989-01-01

    The QPNM equations are derived taking account of p-h and p-p interactions. The calculated quadrupole, octupole and hexadecapole vibrational states in 168 Er, 172 Yb and 178 Hf are found to be reasonale agreement with experimental data. It is shown that distribution of the Eλ strength in some deformed nuclei differs from the standard one. There are cases when for a given K π and Eλ strength is concentrated not on the first but on higher-lying states. The assertion made earlier about the absence of collective two-phonon states in deformed nuclei is confirmed. 44 refs.; 1 fig.; 6 tabs

  20. Nuclear spectroscopy in the rare earth region near the proton drip line

    International Nuclear Information System (INIS)

    Toth, K.S.; Nitschke, J.M.; Wilmarth, P.A.; Vierinen, K.S.

    1989-01-01

    We have used the isotope separator facility OASIS, on-line at the Lawrence Berkeley Laboratory SuperHILAC, to investigate rare earth nuclei close to the proton drip line. Single-particle states near the 82-neutron shell have been examined and their excitation energies determined. Numerous new isotopes, isomers, and β-delayed proton emitters have been discovered. In addition, the α-decay properties of nuclides with N ≥ 84 have been reexamined; this has led to the discovery of several previously unobserved α transitions. The overall experimental program is summarized and some recently obtained results on 145 Dy, 147 Er, 147 Tm, 153 Lu, 155 Lu, and 157 Lu are discussed. 20 refs., 11 figs., 11 tabs

  1. Effect of microalloying with rare-earth on recrystallization behaviour and damping properties of Mg sheets

    International Nuclear Information System (INIS)

    Ma, Ning; Peng, Qiuming; Pan, Junling; Li, Hui; Xiao, Wenlong

    2014-01-01

    Highlights: • Rare earth additions accelerate recovery, but retard recrystallization. • Internal peak at mediate temperatures corresponds to grain boundary relaxation. • Internal peak at elevated temperature is a recrystallization peak. • Grain size, basal texture and dislocation density affect damping remarkably. - Abstract: The effect of a small amount of rare earth elements (RE: Nd and Dy, 0.5 wt.%) on recrystallization behaviour, microstructural evolution and damping properties of deformed Mg sheets have been investigated. The recrystallization behaviour was analyzed in terms of the Johnson–Mehl–Avrami–Kolmogorov model via the variation of microhardness. The Avrami exponent of pure Mg sheet ranged from 1.02 to 1.16, and it was reduced by adding REs. The acceleration of recovery and retardation of recrystallization were detected by the presence of REs. Three point bending was carried out to assess damping properties. At the temperature of ∼150 °C, the damping peak corresponds to grain boundary relaxation, which was affected by grain size, basal texture and the variation of dislocation density on basal plane. At elevated temperatures, a non-thermal activated peak was mainly dependent upon annealing condition, where its height and temperature were increased by adding REs, assigning to be a recrystallization peak

  2. The formation of crystals in glasses containing rare earth oxides

    Energy Technology Data Exchange (ETDEWEB)

    Fadzil, Syazwani Mohd [Pohang University of Science and Technology (POSTECH), Pohang (Korea, Republic of); Hrma, Pavel [Pohang University of Science and Technology (POSTECH), Pohang, South Korea and Pacific Northwest National Laboratory, Richland, Washington (United States); Crum, Jarrod [Pacific Northwest National Laboratory, Richland, Washington (United States); Siong, Khoo Kok; Ngatiman, Mohammad Fadzlee; Said, Riduan Mt [National University of Malaysia, Bandar Baru Bangi, Selangor (Malaysia)

    2014-02-12

    Korean spent nuclear fuel will reach the capacity of the available temporary storage by 2016. Pyroprocessing and direct disposal seems to be an alternative way to manage and reuse spent nuclear fuel while avoiding the wet reprocessing technology. Pyroprocessing produces several wastes streams, including metals, salts, and rare earths, which must be converted into stabilized form. A suitable form for rare earth immobilization is borosilicate glass. The borosilicate glass form exhibits excellent durability, allows a high waste loading, and is easy to process. In this work, we combined the rare earths waste of composition (in wt%) 39.2Nd{sub 2}O{sub 3}–22.7CeO{sub 2}–11.7La{sub 2}O{sub 3}–10.9PrO{sub 2}–1.3Eu{sub 2}O{sub 3}–1.3Gd{sub 2}O{sub 3}–8.1Sm{sub 2}O{sub 3}–4.8Y{sub 2}O{sub 3} with a baseline glass of composition 60.2SiO{sub 2}–16.0B{sub 2}O{sub 3}–12.6Na{sub 2}O–3.8Al{sub 2}O{sub 3}–5.7CaO–1.7ZrO{sub 2}. Crystallization in waste glasses occurs as the waste loading increases. It may produce complicate glass processing and affect the product quality. To study crystal formation, we initially made glasses containing 5%, 10% and 15% of La{sub 2}O{sub 3} and then glasses with 5%, 10% and 15% of the complete rare earth mix. Samples were heat-treated for 24 hours at temperatures 800°C to 1150°C in 50°C increments. Quenched samples were analyzed using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, and x-ray diffraction. Stillwellite (LaBSiO{sub 5}) and oxyapatite (Ca{sub 2}La{sub 8}Si{sub 6}O{sub 26}) were found in glasses containing La{sub 2}O{sub 3}, while oxyapatite (Ca{sub 2}La{sub 8}Si{sub 6}O{sub 26} and NaNd{sub 9}Si{sub 6}O{sub 26}) precipitated in glasses with additions of mixed rare earths. The liquidus temperature (T{sub L}) of the glasses containing 5%, 10% and 15% La{sub 2}O{sub 3} were 800°C, 959°C and 986°C, respectively; while T{sub L} was 825°C, 1059°C and 1267°C for glasses

  3. Effect of the Pauli principle on the excited states of doubly-even deformed nuclei

    International Nuclear Information System (INIS)

    Jolos, R.V.; Molina, J.L.; Soloviev, V.G.

    1980-01-01

    It is shown that the commutation relations between the quasiparticles forming phonons can correctly be taken into account within the quasiparticle-phonon nuclear model. The doubly-even deformed nuclei with the isoscalar and isovector multipole-multipole forces are studied. The exact and approximate secular equations are derived. It is shown that the two-phonon poles in the secular equation are shifted due to the Pauli principle. These shifts are large for the two identical collective phonons. In some cases pronounced shifts are found for the poles composed of a low-lying collective phonon and a collective phonon forming the giant resonance. In other cases the shifts are not large, as a rule. (orig.) 891 FKS/orig. 892 MB

  4. Scissors and unique-parity modes of M1 excitation in deformed nuclei

    International Nuclear Information System (INIS)

    Otsuka, T.

    1989-01-01

    In this paper the possible modes of M1 excitation in deformed even-even nuclei are studied in terms of the particle-number-conserved Nilsson + BCS formalism with the standard parameters. The spurious motion with respect to the rotation is removed. In addition to the Scissors mode, the Unique-Parity Spin and Normal-Parity Spin modes are suggested, although the latter may be fragmented to a large extent. The Scissors mode carries most of the orbital strength, while the others the spin strength. The proton Unique-Parity (i.e. Oh 11/12 ) Spin mode for 164 Dy is obtained just below Ex = 3 MeV with B(M1) ∼ 0.2 μ 2 N ) in the sum rule limit. This is in a good agreement to the recent experimental data

  5. One- and two-phonon excitations in strongly deformed triaxial nuclei

    International Nuclear Information System (INIS)

    Hagemann, G.B.

    2003-01-01

    The wobbling mode is uniquely related to triaxiality and introduces a series of bands with increasing wobbling phonon number, n ω , and a characteristic large Δ nω =1 E2 strength between the bands. The pattern of γ-transitions between the wobbling excitations will be influenced by the presence of an aligned particle. Evidence for the wobbling mode was obtained recently, and even a two-phonon wobbling excitation has now been identified in 163 Lu. The similarity of the data in 163 Lu to new strongly deformed triaxial bands and connecting transitions in the neighbouring nuclei, 165 Lu and 167 Lu, establishes wobbling as a more general phenomenon in this region. (author)

  6. Extreme magnetoresistance in magnetic rare-earth monopnictides

    Science.gov (United States)

    Ye, Linda; Suzuki, Takehito; Wicker, Christina R.; Checkelsky, Joseph G.

    2018-02-01

    The acute sensitivity of the electrical resistance of certain systems to magnetic fields known as extreme magnetoresistance (XMR) has recently been explored in a new materials context with topological semimetals. Exemplified by WTe2 and rare-earth monopnictide La(Sb,Bi), these systems tend to be nonmagnetic, nearly compensated semimetals and represent a platform for large magnetoresistance driven by intrinsic electronic structure. Here we explore electronic transport in magnetic members of the latter family of semimetals and find that XMR is strongly modulated by magnetic order. In particular, CeSb exhibits XMR in excess of 1.6 ×106% at fields of 9 T whereas the magnetoresistance itself is nonmonotonic across the various magnetic phases and shows a transition from negative magnetoresistance to XMR with fields above magnetic ordering temperature TN. The magnitude of the XMR is larger than in other rare-earth monopnictides including the nonmagnetic members and follows a nonsaturating power law to fields above 30 T. We show that the overall response can be understood as the modulation of conductivity by the Ce orbital state and for intermediate temperatures can be characterized by an effective medium model. Comparison to the orbitally quenched compound GdBi supports the correlation of XMR with the onset of magnetic ordering and compensation and highlights the unique combination of orbital inversion and type-I magnetic ordering in CeSb in determining its large response. These findings suggest a paradigm for magneto-orbital control of XMR and are relevant to the understanding of rare-earth-based correlated topological materials.

  7. High purity neodymium acetate from mixed rare earth carbonates

    International Nuclear Information System (INIS)

    Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A.; Pedreira, Walter dos R.

    2011-01-01

    A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd 2 O 3 in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in μg g -1 : Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

  8. Study of rare earth elements as material for control rods

    International Nuclear Information System (INIS)

    1975-03-01

    The properties of rare earth elements as the material for control rods were studied. The rare earth elements, especially europium oxide, has the nuclear property corresponding to boron carbide, and its neutron absorption process does not emit alpha particles. The elements produced as a result of neutron capture also have large capture cross sections. This paper presents survey report on the properties and nuclear properties of rare earth elements, and comparison with other materials. Preliminary experiment was performed to make the pellets of europium oxide, and is described in this paper. Because of large density, the crystal form to be made was monoclinic system. Europium hydroxide was decomposed at 1000 0 C and 10 -5 torr. The obtained powder was dipped into benzene, and dryed in the air at 450 0 C. This powder was pressed and sintered in the air for one hour at 1500 0 C. The density of the obtained pellets was 97.0% of the theoretical density. The cross section of europium for fast neutron absorption is not yet accurately obtained, and is in the range between 4.65 and 8.5 barn for 151 Eu(n,γ) reaction. Since chain absorption reaction is caused in Eu, the overall capability of neutron absorption is not much changed by the loss of original material due to absorption. The pellets of europium oxide may be handled in air, but must be kept in dry atmosphere. The reactions of europium oxide with various metals were also investigated. The characteristic behavior in case of irradiation depends on the amount of silicon contained, and it was very good if the amount was less than 0.03%. (Kato, T.)

  9. Rare-earth doped boron nitride nanotubes: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wellington Marcos; Sousa, Edesia Martins Barros de, E-mail: wellingtonmarcos@yahoo.com.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    Full text: Boron nitride is a heat and chemically resistant refractory compound of boron and nitrogen atoms with the chemical formula BN. This structure exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form (h-BN) corresponding to graphite is the most stable and soft among BN polymorph. However, boron nitride nanotubes (BNNTs) were first time synthesized in 1995 [1] and have a type of one-dimensional (1D) nanostructure. Recently the BNNTs have attracted significant interest for scientific and technological applications due to their Wide bandgap. The Wide-bandgap semiconductors doped with rare-earth are considered as a new type of luminescent material, combining special Wide bandgap semiconducting properties with the rare-earth luminescence feature. BNNTs have a stable wide bandgap of 5.5 eV and super thermal and chemical stabilities, which make BNNTs an ideal nanosized luminescent material [2]. In this study, we report a simple and efficient route for the synthesis of BNNTs doped with samarium and europium. High quality BNNTs doped was produced via CVD technique using NH{sub 3} and N{sub 2} gases as source. Boron amorphous, catalyst and oxides rare-earth powder were used as precursor. Detailed studies involving energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed in order to characterize the BNNTs as grown. [1] Chopra, N. G.; Luyken, R. J. et al. Science, v. 269, p. 966-967, 1995. [2] Chen, H.; Chen, Y. et al. Adv. Matter. v. 19, p. 1845-1848, 2007. (author)

  10. Rare-earth doped boron nitride nanotubes: Synthesis and characterization

    International Nuclear Information System (INIS)

    Silva, Wellington Marcos; Sousa, Edesia Martins Barros de

    2016-01-01

    Full text: Boron nitride is a heat and chemically resistant refractory compound of boron and nitrogen atoms with the chemical formula BN. This structure exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form (h-BN) corresponding to graphite is the most stable and soft among BN polymorph. However, boron nitride nanotubes (BNNTs) were first time synthesized in 1995 [1] and have a type of one-dimensional (1D) nanostructure. Recently the BNNTs have attracted significant interest for scientific and technological applications due to their Wide bandgap. The Wide-bandgap semiconductors doped with rare-earth are considered as a new type of luminescent material, combining special Wide bandgap semiconducting properties with the rare-earth luminescence feature. BNNTs have a stable wide bandgap of 5.5 eV and super thermal and chemical stabilities, which make BNNTs an ideal nanosized luminescent material [2]. In this study, we report a simple and efficient route for the synthesis of BNNTs doped with samarium and europium. High quality BNNTs doped was produced via CVD technique using NH 3 and N 2 gases as source. Boron amorphous, catalyst and oxides rare-earth powder were used as precursor. Detailed studies involving energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscope (TEM) were performed in order to characterize the BNNTs as grown. [1] Chopra, N. G.; Luyken, R. J. et al. Science, v. 269, p. 966-967, 1995. [2] Chen, H.; Chen, Y. et al. Adv. Matter. v. 19, p. 1845-1848, 2007. (author)

  11. Accurate masses of unstable rare earth isotopes by ISOLTRAP

    International Nuclear Information System (INIS)

    Beck, D.; Ames, F.; Audi, G.

    2000-05-01

    Direct mass measurements of neutron-deficient rare earth isotopes in the vicinity of 146 Gd were performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. This paper reports on the measurement of more than 40 isotopes of the elements Pr, Nd, Pm, Sm, Eu, Dy and Ho, that have been measured with a typical accuracy of δm ∼ 14 keV. An atomic mass evaluation has been performed taking into account other experimental mass values via a least-squares adjustment. The results of the adjustment are discussed. (orig.)

  12. Study on speciation of rare earth elements in soil

    International Nuclear Information System (INIS)

    Wang Yuqi; Sun Jingxin; Chen Hongmin; Guo Fanqing; Wang Lijun; Zhang Shen

    1996-01-01

    The contents of rare earth elements (REE) in red soil, yellow brown soil and leached chernozem are studied. After extracted sequentially, REE in these soils are fractionated into seven forms, i.e., (I) water soluble, (II) exchangeable, (III) loosely bound to organic mater, (IV) bound to carbonate and specifically absorbed, (V) bound to Fe-Mn oxides, (VI) tightly bound to organic matter and (VII) residual forms. The contents of REE in every form are determined by NAA (neutron activation analysis). The results show that REE in soils mainly exist in residual form and REE in soluble forms are very limited (<7%)

  13. Fluorescence of europium in oxyhalides of rare earths

    International Nuclear Information System (INIS)

    Hoelsae, Jorma; Niinistoe, Lauri

    1980-01-01

    Fluorescence spectra of the Eu 3+ ion embedded in rare earth oxyhalides LnOX (Ln=Y, La, Gd; X=Cl, Br) have been obtained at 300, 77 and 4.2 K. The number of lines observed for each transition is compatible to the one allowed by the Csub(4v) point site symmetry predicted by crystallography. Positions of Stark levels have been analyzed in terms of nephelauxetic effect and strength of the crystal field parameters, versus host cation and anion. Moreover, the so-called 'forbidden' transition 5 D 0 → 7 F 0 exhibits a strong intensity, also varying versus the matrix [fr

  14. Crystal field in rare-earth metals and intermetallic compounds

    International Nuclear Information System (INIS)

    Ray, D.K.

    1978-01-01

    Reasons for the success of the crystal-field model for the rare-earth metals and intermetallic compounds are discussed. A review of some of the available experimental results is made with emphasis on cubic intermetallic compounds. Various sources of the origin of the crystal field in these metals are discussed in the background of the recent APW picture of the conduction electrons. The importance of the non-spherical part of the muffin-tin potential on the single-ion anisotropy is stressed. (author)

  15. Study about chemical and radiological toxicity of rare earths

    International Nuclear Information System (INIS)

    Goncalez, O.L.

    1987-02-01

    The maximum permissible concentration in workplace air for an admixture of rare earths is calculated to be 1.47 mg/m 3 of air. This value takes into account the biological mean-life of those chemical elements in human body and acute toxicological data. A simplified mathematical models is done that describes the body content of this product as a time function, for cronic intoxication by air particulate inhalation. Under the radiological point of view the limit calculated for the air concentration is about 100 mg/m 3 , showing that the chemical toxity of these products is predominant. (Author) [pt

  16. Rare earth element patterns in biotite, muscovite and tourmaline minerals

    International Nuclear Information System (INIS)

    Laul, J.C.; Lepel, E.A.

    1986-01-01

    Rare earth element concentrations in the minerals biotite and muscovite from the mica schist country rocks of the Etta pegmatite and tourmalines from the Bob Ingersoll pegmatite have been measured by INAA and CNAA. The concentrations range from 10 -4 g/g to 10/sup -10g//sub g/. The REE patterns of biotite, muscovite and tourmaline reported herein are highly fractionated from light to heavy REE. The REE concentrations in biotite and muscovite are high and indigenous. The pegmatite tourmalines contain low concentrations of REE. Variations in tourmaline REE patterns reflect the geochemical evolution of pegmatite melt/fluid system during crystallization

  17. Marine geochemistry of the rare earth elements: a review

    International Nuclear Information System (INIS)

    Kennedy, H.; Elderfield, H.

    1984-01-01

    The rare earth elements (REE) form a coherent group because of their systematic decrease in atomic radii with increasing atomic number and predominant +3 oxidation state. This makes them particularly useful in the study of marine geochemistry. The fact that two members of the group are often found in anomalous oxidation states allows a study of the fractionation of these REE from their neighbours and provides an insight into the geochemical behaviour of the REE in the marine environment. Thus the chemistry and relative abundances of the REE can be used to assess the origin and depositional environments of modern sediments. (author)

  18. Calculations in solvent extraction of rare earth metals

    International Nuclear Information System (INIS)

    Sadanandam, R.; Sharma, A.K.; Fonseca, M.F.; Hubli, R.C.; Suri, A.K.; Singh, D.K.

    2010-01-01

    The paper deals with calculation of number of countercurrent stages in solvent extraction of rare earths both under total reflux and partial reflux conditions to achieve a given degree of purification and recovery. The use of Fenske's equation normally used for separation by distillation is proposed to calculate the number of stages required under total reflux, replacing relative volatility by separation factor. Kremser's equations for extraction and scrubbing are used to calculate the number of stages in extraction and scrubbing modules under partial reflux conditions. McCabe-Thiele's approach is also adopted to arrive at the number of scrubbing stages. (author)

  19. Spectra of fluorinated rare earth. beta. -diketonates with added ligands

    Energy Technology Data Exchange (ETDEWEB)

    Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Krasovskaya, L.I. (AN Belorusskoj SSR, Minsk. Inst. Fiziki; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)

    1984-01-01

    Different-ligand rare earth complexes are synthesized. Fluorated ..beta..-diketones, triethylphosphine oxide and trifluoracetic acid are used as active ligands. Mass-spectra of low and high resolution are taken at the energy of ionizing electrons of 70 eV, as well as luminescence spectra of complexes. Fragmentation ways of complexes decomposition under electron shock are studied. A series of changing the bound strength of additional ligands with europium in mixed complexes is determined. It is shown that the introduction of additional ligands can purposefully change physical and chemical properties of complexes.

  20. Morphology and pore structure of rare earth oxides

    International Nuclear Information System (INIS)

    Bruce, L.A.; Hoang, M.; Hardin, S.; Turney, T.W.

    1991-01-01

    The morphology observed by transmission electron microscopy of rare earth oxides, prepared by two different routes, has been related to adsorption, characteristics for nitrogen at 77 K. The most common morphology was that of thin sheets, then small equiaxed particles, and, more rarely, rod-like particles. The presence of small equiaxed particles was found to be a prerequisite for adsorption hysteresis. Evaluation of linear 't' plots indicated freedom from micropores in all samples, but positive deviations in the presence of sheet morphology at high relative pressures left open the possibility of wedge-like pores in these samples. 14 refs., 3 tabs., 5 figs

  1. Solution thermodynamics of rare-earth metal ions - physicochemical study-

    Energy Technology Data Exchange (ETDEWEB)

    Amerkhanova, Sh K; Shlyapov, R M; Uali, A S [Buketov Karaganda state university, University str., 28, Karaganda, 100028 (Kazakhstan)], E-mail: amerkhanova_sh@mail.ru

    2009-02-01

    The results of the studying of interactions in multicomponent systems 'polyvinyl alcohol (PVA) - rare-earth element ion - nitrate of sodium - water' are represented. It is established that for rubidium (I) ions temperature and ionic strength is render destroying action, and for yttrium (III) ions the influence of these factors has return character which is connected with features of an electronic structure of metal ion. It is revealed that a dominating role of non-electrostatic formation composed, hence, the formation of donor-acceptor connection of 'metal - ligand' occurs through atom of oxygen.

  2. Electronic Structure of Rare-Earth Metals. II. Positron Annihilation

    DEFF Research Database (Denmark)

    Williams, R. W.; Mackintosh, Allan

    1968-01-01

    of Loucks shows that the independent-particle model gives a good first approximation to the angular distribution, although correlation effects probably smear out some of the structure. The angular distributions from the heavy rare-earth metals are very similar to that from Y and can be understood....... In the spiral phase of Ho, the structure in the c-axis distribution is much reduced, indicating that the Fermi surface is substantially modified by the magnetic ordering, as expected. The photon distribution from the equiatomic Ho-Er alloy is very similar to those from the constituent metals, although...

  3. Thermochemical properties of rare earth complexes with salicylic acid

    International Nuclear Information System (INIS)

    Yang Xuwu; Sun Wujuan; Ke Congyu; Zhang Hangguo; Wang Xiaoyan; Gao Shengli

    2007-01-01

    Fourteen rare earth complexes with salicylic acid RE(HSal) 3 .nH 2 O (HSal = C 7 H 5 O 3 ; RE = La-Sm, n = 2; RE = Eu-Lu, n = 1) were synthesized and characterized by elemental analysis, and their thermal decomposition mechanism were studied with TG-DTG technology. The constant-volume combustion energies of complexes, Δ c U, were determined by a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, Δ c H m 0 , and standard molar enthalpies of formation, Δ f H m o , were calculated

  4. Rare earth element and rare metal inventory of central Asia

    Science.gov (United States)

    Mihalasky, Mark J.; Tucker, Robert D.; Renaud, Karine; Verstraeten, Ingrid M.

    2018-03-06

    Rare earth elements (REE), with their unique physical and chemical properties, are an essential part of modern living. REE have enabled development and manufacture of high-performance materials, processes, and electronic technologies commonly used today in computing and communications, clean energy and transportation, medical treatment and health care, glass and ceramics, aerospace and defense, and metallurgy and chemical refining. Central Asia is an emerging REE and rare metals (RM) producing region. A newly compiled inventory of REE-RM-bearing mineral occurrences and delineation of areas-of-interest indicate this region may have considerable undiscovered resources.

  5. The Marine Geochemistry of the Rare Earth Elements

    Science.gov (United States)

    1983-09-01

    C3): 2045-2056. BACON, M.P., P.G. BREWER, D.W. SPENCER, T.W. MURRAY & T. GODDARD (1980). Lead - 210 , polonium - 210 , manganese and iron in the Cariaco...191 La and Pr 197 Ce: its oxidation and reduction 197 Eu 207 4.5. Conclusions 210 CHAPTER 5. Behaviour of the Rare Earth Elements in anoxic waters of...seawater and algal food . When the radioactive particles were no longer available, the accumulated radioactivity of the zooplankters was rapidly lost

  6. Subsurface contributions in epitaxial rare-earth silicides

    Energy Technology Data Exchange (ETDEWEB)

    Luebben, Olaf; Shvets, Igor V. [Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), School of Physics, Trinity College, Dublin (Ireland); Cerda, Jorge I. [Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, Madrid (Spain); Chaika, Alexander N. [Institute of Solid State Physics, RAS, Chernogolovka (Russian Federation)

    2015-07-01

    Metallic thin films of heavy rare-earth silicides epitaxially grown on Si(111) substrates have been widely studied in recent years because of their appealing properties: unusually low values of the Schottky barrier height, an abrupt interface, and a small lattice mismatch. Previous studies also showed that these silicides present very similar atomic and electronic structures. Here, we examine one of these silicides (Gd{sub 3}Si{sub 5}) using scanning tunneling microscopy (STM) image simulations that go beyond the Tersoff-Hamann approach. These simulations strongly indicate an unusual STM depth sensitivity for this system.

  7. Effect of deformations on the compactness of odd-Z superheavy nuclei formed in cold and hot fusion reactions

    Science.gov (United States)

    Kaur, Gurjit; Sandhu, Kirandeep; Sharma, Manoj K.

    2018-03-01

    Using the extended fragmentation theory, the compactness of hot and cold fusion reactions is analyzed for odd-Z nuclei ranging Z = 105- 117. The calculations for the present work are carried out at T = 0MeV and ℓ = 0 ħ, as the temperature and angular momentum effects remain silent while addressing the orientation degree of freedom (i.e. compact angle configuration). In the hot fusion, 48Ca (spherical) + actinide (prolate) reaction, the non-equatorial compact (nec) shape is obtained for Z = 113 nucleus. On the other hand, Z > 113 nuclei favor equatorial compact (ec) configuration. The distribution of barrier height (VB) illustrate that the ec-shape is obtained when the magnitude of quadrupole deformation of the nucleus is higher than the hexadecupole deformation. In other words, negligible or small -ve β4-deformations support ec configurations. On the other hand, large (+ve) magnitude of the β4-deformation suggests that the configuration appears for compact angle θc < 90 °, leading to nec structure. Similar deformation effects are observed for Bi-induced reactions, in which not belly-to-belly compact (nbbc) configurations are seen at θc = 42 °. In addition to the effect of β2 and β4-deformations, the exclusive role of octupole deformations (β3) is also analyzed. The β3-deformations do not follow the reflection symmetry as that of β2 and β4, leading to the possible occurrence of compact configuration within 0° to 180° angular range.

  8. Low-spin identical bands in neighboring odd-A and even-even nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Winchell, D.F.; Garrett, J.D.; Smith, A.

    1992-01-01

    A comprehensive study of odd-A rotational bands in normally deformed rare-earth nuclei indicates that a large number of seniority-one configurations (21% for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models of nuclear pair correlation, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority

  9. Low-spin identical bands in neighboring odd-A and even-even nuclei

    International Nuclear Information System (INIS)

    Baktash, C.; Winchell, D.F.; Garrett, J.D.; Smith, A.

    1993-01-01

    A comprehensive study of odd-A rotational bands in normally deformed rare-earth nuclei indicates that a large number of seniority-one configurations (21 % for odd-Z nuclei) at low spin have moments of inertia nearly identical to that of the seniority-zero configuration of the neighboring even-even nucleus with one less nucleon. It is difficult to reconcile these results with conventional models of nuclear pair correlation, which predict variations of about 15% in the moments of inertia of configurations differing by one unit in seniority. (orig.)

  10. Proceedings of the international conference on science, technology and applications of rare earths

    International Nuclear Information System (INIS)

    2015-01-01

    Rare Earth Elements (REEs) are extensively used in clean energy applications like wind turbines, hybrid car batteries/electric motors, solar energy collectors, permanent magnets, phosphors, multifunctional pigments, thin film technologies, defence - related systems, etc. The use of rare earth elements in modern technology has increased several folds over the past few years in both domestic and international sectors due to the growing economy. The current global demand for rare earths is expected to provide a myriad of business opportunities for rare earth industries across the world including India for the utilization of rare earths in green energy, technology and industry. Papers relevant to INIS are indexed separately

  11. Creating a multi-national development platform: Thorium energy and rare earth value chain

    International Nuclear Information System (INIS)

    Kennedy, J.; Kutsch, J.

    2014-01-01

    Rare earths and thorium are linked at the mineralogical level. Changes in thorium regulations and liabilities resulted in the development of excessive market concentrations in the rare earth value chain. High value monazite rare earth resources, a by-product of heavy mineral sands mining, constituted a significant portion of global rare earth supply (and nearly 100% of heavy rare earths) until legislative changes, interpretation and enforcement regarding “source materials” in the early 1980s eliminated these materials from the supply chain.

  12. Samarium-cobalt type rare earth permanent magnets

    International Nuclear Information System (INIS)

    Kamat, S.V.

    2014-01-01

    Permanent magnets are one of the oldest and largest applications of magnetic materials and form an integral part of our modern industrial society. They belong to a special class of functional materials and are characterized for remanence (flux output from the magnet), coercivity (resistance to demagnetization) and energy product (material energy density) from the second quadrant of the magnetic hysteresis loop. The reliability, stability, size, weight, cost and performance of many electro-technical devices depend mainly on the properties of permanent magnets used in them. There are three important families of permanent magnets viz., Ferrites, Alnicos and Rare Earth Permanent Magnets (REPMs) with energy product values ranging from 3 to 50 MGOe and among the front ranking high performance REPMs, SmCo 5 , Sm 2 Co 17 type and NdFeB alloys are technologically the most important materials. They are used in a wide range of applications ranging from consumer products to very specialized areas of tele-communications, microelectronics, defence, space, avionics etc. While NdFeB has the highest energy product, Sm-Co based magnets are preferred for most critical applications where temperature stability of magnetic properties is essential because of their significantly higher Curie temperatures. In this presentation some of the key challenges associated with these Sm-Co based rare earth permanent magnets will be highlighted. (author)

  13. High purity samarium oxide from mixed rare earth carbonates

    International Nuclear Information System (INIS)

    Queiroz, Carlos A. da S.; Seneda, Jose A.; Vasconcellos, Mari E. de; Pedreira Filho, Walter dos R.

    2013-01-01

    A simple and economical chemical process for the production of highly pure samarium oxides is discussed. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin that is typically employed in water treatment processes to fractionate rare earth elements (REE) without the use of retention ions. Under these conditions, 99.9% pure Sm 2 O 3 was eluted using the ammonium salt of ethylenediaminetetraacetic acid (EDTA) at a controlled pH. The EDTA-samarium complex was separated from EDTA and then precipitated as oxalate and fired to samarium oxide. Molecular absorption spectrophotometry was used to monitor the samarium content during the proposed process, and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium oxide. Typical samarium oxide obtained from the proposed procedure contained the following contaminants in micrograms per gram: Sc (20.90); Y (11.80); La (8.4); Ce (4.3); Pr (2.5); Nd (5.1); Eu (94); Gd (114); Tb (3.6); Dy (2.5), Ho (2.3); Er (3.0); Tm (2.3); Yb (38,2); Lu (25.6). The high-purity samarium oxides produced in the present study can be used as an alternative to imported products in research and development applications. (author)

  14. Determination of free boron in rare earth hexaborides

    International Nuclear Information System (INIS)

    Kugaj, L.N.; Nazarchuk, T.N.

    1975-01-01

    The method of N.I. Timofeeva et al. (1968) for the determination of free B in rare earth hexaborides was modified by replacing the 1:10 HNO 3 by nonoxidizing 2:1 or 3:1 H 2 SO 4 to dissolve the hexaborides and leave free B in the residue. A sample of 0.5-1.0 g rare earth hexaboride was heated in 50-80 ml 3:1 H 2 SO 4 at 210 0 for 2 hr, and the cool solutions was diluted. The residue containing free B and B 4 C was filtered, rinsed, and heated in dilute HNO 3 at mild temperature for 15-20 min. The filtrate was separated from insoluble B 4 C, neutralized with 10% NaOH, and H 3 BO 3 was titrated with NaOH in the presence of inverted sugar vs. phenophthalein. The free B content was underestimated by less than or equal to 4.3% in nearly all cases. The proposed technique is applicalbe to hexaborides of La, Y, Ce, Pr, Nd, Sm, Gd, and Eu

  15. Bacterial Cell Surface Adsorption of Rare Earth Elements

    Science.gov (United States)

    Jiao, Y.; Park, D.; Reed, D.; Fujita, Y.; Yung, M.; Anderko, A.; Eslamimanesh, A.

    2015-12-01

    Rare earth elements (REE) play a critical role in many emerging clean energy technologies, including high-power magnets, wind turbines, solar panels, hybrid/electric vehicle batteries and lamp phosphors. In order to sustain demand for such technologies given current domestic REE shortages, there is a need to develop new approaches for ore processing/refining and recycling of REE-containing materials. To this end, we have developed a microbially-mediated bioadsorption strategy with application towards enrichment of REE from complex mixtures. Specifically, the bacterium Caulobacter crescentus was genetically engineered to display lanthanide binding tags (LBTs), short peptides that possess high affinity and specificity for rare earth elements, on its cell surface S-layer protein. Under optimal conditions, LBT-displayed cells adsorbed greater than 5-fold more REE than control cells lacking LBTs. Competition binding experiments with a selection of REEs demonstrated that our engineered cells could facilitate separation of light- from heavy- REE. Importantly, binding of REE onto our engineered strains was much more favorable compared to non-REE metals. Finally, REE bound to the cell surface could be stripped off using citrate, providing an effective and non-toxic REE recovery method. Together, this data highlights the potential of our approach for selective REE enrichment from REE containing mixtures.

  16. Rare-earth-metal nitridophosphates through high-pressure metathesis

    International Nuclear Information System (INIS)

    Kloss, Simon David; Schnick, Wolfgang

    2015-01-01

    Developing a synthetic method to target an broad spectrum of unknown phases can lead to fascinating discoveries. The preparation of the first rare-earth-metal nitridophosphate LiNdP_4N_8 is reported. High-pressure solid-state metathesis between LiPN_2 and NdF_3 was employed to yield a highly crystalline product. The in situ formed LiF is believed to act both as the thermodynamic driving force and as a flux to aiding single-crystal formation in dimensions suitable for crystal structure analysis. Magnetic properties stemming from Nd"3"+ ions were measured by SQUID magnetometry. LiNdP_4N_8 serves as a model system for the exploration of rare-earth-metal nitridophosphates that may even be expanded to transition metals. High-pressure metathesis enables the systematic study of these uncharted regions of nitride-based materials with unprecedented properties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. RARE EARTH ELEMENT IMPACTS ON BIOLOGICAL WASTEWATER TREATMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Y.; Barnes, J.; Fox, S.

    2016-09-01

    Increasing demand for rare earth elements (REE) is expected to lead to new development and expansion in industries processing and or recycling REE. For some industrial operators, sending aqueous waste streams to a municipal wastewater treatment plant, or publicly owned treatment works (POTW), may be a cost effective disposal option. However, wastewaters that adversely affect the performance of biological wastewater treatment at the POTW will not be accepted. The objective of our research is to assess the effects of wastewaters that might be generated by new rare earth element (REE) beneficiation or recycling processes on biological wastewater treatment systems. We have been investigating the impact of yttrium and europium on the biological activity of activated sludge collected from an operating municipal wastewater treatment plant. We have also examined the effect of an organic complexant that is commonly used in REE extraction and separations; similar compounds may be a component of newly developed REE recycling processes. Our preliminary results indicate that in the presence of Eu, respiration rates for the activated sludge decrease relative to the no-Eu controls, at Eu concentrations ranging from <10 to 660 µM. Yttrium appears to inhibit respiration as well, although negative impacts have been observed only at the highest Y amendment level tested (660 µM). The organic complexant appears to have a negative impact on activated sludge activity as well, although results are variable. Ultimately the intent of this research is to help REE industries to develop environmentally friendly and economically sustainable beneficiation and recycling processes.

  18. Game meat authentication through rare earth elements fingerprinting

    International Nuclear Information System (INIS)

    Danezis, G.P.; Pappas, A.C.; Zoidis, E.; Papadomichelakis, G.; Hadjigeorgiou, I.; Zhang, P.; Brusic, V.; Georgiou, C.A.

    2017-01-01

    Accurate labelling of meat (e.g. wild versus farmed, geographical and genetic origin, organic versus conventional, processing treatment) is important to inform the consumers about the products they buy. Meat and meat products declared as game have higher commercial value making them target to fraudulent labelling practices and replacement with non-game meat. We have developed and validated a new method for authentication of wild rabbit meat using elemental metabolomics approach. Elemental analysis was performed using rapid ultra-trace multi-element measurement by inductively coupled plasma mass spectrometry (ICP-MS). Elemental signatures showed excellent ability to discriminate the wild rabbit from non-wild rabbit meat. Our results demonstrate the usefulness of metabolic markers -rare earth signatures, as well as other trace element signatures for game meat authentication. - Highlights: • Elemental metabolomics is a powerful new methodology for authentication of game rabbit meat. • New method for meat authentication utilizing rare earths elemental signatures. • Samples are compared to group signatures using angular and Euclidean distances. • Meat reference materials (>70 elements) can be used for cross-comparison between studies.

  19. Assessing rare earth elements in quartz rich geological samples.

    Science.gov (United States)

    Santoro, A; Thoss, V; Ribeiro Guevara, S; Urgast, D; Raab, A; Mastrolitti, S; Feldmann, J

    2016-01-01

    Sodium peroxide (Na2O2) fusion coupled to Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS/MS) measurements was used to rapidly screen quartz-rich geological samples for rare earth element (REE) content. The method accuracy was checked with a geological reference material and Instrumental Neutron Activation Analysis (INAA) measurements. The used mass-mode combinations presented accurate results (only exception being (157)Gd in He gas mode) with recovery of the geological reference material QLO-1 between 80% and 98% (lower values for Lu, Nd and Sm) and in general comparable to INAA measurements. Low limits of detection for all elements were achieved, generally below 10 pg g(-1), as well as measurement repeatability below 15%. Overall, the Na2O2/ICP-MS/MS method proved to be a suitable lab-based method to quickly and accurately screen rock samples originating from quartz-rich geological areas for rare earth element content; particularly useful if checking commercial viability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. MBE growth and characterisation of light rare-earth superlattices

    DEFF Research Database (Denmark)

    Ward, R.C.C.; Wells, M.R.; Bryn-Jacobsen, C.

    1996-01-01

    The molecular beam epitaxy growth techniques which have already successfully produced a range of heavy rare-earth superlattices have now been extended to produce superlattices of two light rare-earth elements, Nd/Pr, as well as superlattices and alloy films of a heavy/light system, Ho/Pr. High......-resolution X-ray diffraction analysis shows the Nd/Pr superlattices to be of high structural quality, while the Ho/Pr superlattices are significantly less so. In the Ho/Pr superlattices, Pr is found to retain its bulk dhcp crystal structure even in thin layers (down to 6 atomic planes thick) sandwiched between...... thick layers of hcp Ho. In addition, neutron diffraction studies of the He/Pr superlattices have shown that the helical Ho magnetic order is not coherent through the dhcp Pr layers, in contrast to previous hcp/hcp superlattices Ho/Y, Ho/Lu and Ho/Er. The series of Ho:Pr alloy films has shown structural...