WorldWideScience

Sample records for spaced scandium atoms

  1. Atomic Transition Probabilities Scandium through Manganese

    International Nuclear Information System (INIS)

    Martin, G.A.; Fuhr, J.R.; Wiese, W.L.

    1988-01-01

    Atomic transition probabilities for about 8,800 spectral lines of five iron-group elements, Sc(Z = 21) to Mn(Z = 25), are critically compiled, based on all available literature sources. The data are presented in separate tables for each element and stage of ionization and are further subdivided into allowed (i.e., electric dipole-E1) and forbidden (magnetic dipole-M1, electric quadrupole-E2, and magnetic quadrupole-M2) transitions. Within each data table the spectral lines are grouped into multiplets, which are in turn arranged according to parent configurations, transition arrays, and ascending quantum numbers. For each line the transition probability for spontaneous emission and the line strength are given, along with the spectroscopic designation, the wavelength, the statistical weights, and the energy levels of the upper and lower states. For allowed lines the absorption oscillator strength is listed, while for forbidden transitions the type of transition is identified (M1, E2, etc.). In addition, the estimated accuracy and the source are indicated. In short introductions, which precede the tables for each ion, the main justifications for the choice of the adopted data and for the accuracy rating are discussed. A general introduction contains a discussion of our method of evaluation and the principal criteria for our judgements

  2. Interaction of scandium and titanium atoms with a carbon surface containing five- and seven-membered rings

    International Nuclear Information System (INIS)

    Krasnov, P. O.; Eliseeva, N. S.; Kuzubov, A. A.

    2012-01-01

    The use of carbon nanotubes coated by atoms of transition metals to store molecular hydrogen is associated with the problem of the aggregation of these atoms, which leads to the formation of metal clusters. The quantum-chemical simulation of cluster models of the carbon surface of a graphene type with scandium and titanium atoms has been performed. It has been shown that the presence of five- and seven-membered rings, in addition to six-membered rings, in these structures makes it possible to strongly suppress the processes of the migration of metal atoms over the surface, preventing their clustering.

  3. Scandium fluorides

    International Nuclear Information System (INIS)

    Melnikov, P.; Nalin, M.; Messaddeq, Y.

    1997-01-01

    A new modification of scandium fluoride has been synthesised. The compound is deficient in fluorine, with the composition ScF 2.76 . It belongs to the tetragonal system, lattice parameters being a=3.792 and c=6.740 A and may be obtained at low temperatures by the decomposition of the precursor NH 4 ScF 4 . The reaction is topotactic, tetragonal parameters of the precursor are a=4.021 and c=6.744 A. Structural relationships with various fluorides and ammonium aminofluorides are discussed. This synthesis route with IR-assisted decomposition should be considered as a soft-chemistry approach. (orig.)

  4. Atoms for space

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.

    1990-10-01

    Nuclear technology offers many advantages in an expanded solar system space exploration program. These cover a range of possible applications such as power for spacecraft, lunar and planetary surfaces, and electric propulsion; rocket propulsion for lunar and Mars vehicles; space radiation protection; water and sewage treatment; space mining; process heat; medical isotopes; and self-luminous systems. In addition, space offers opportunities to perform scientific research and develop systems that can solve problems here on Earth. These might include fusion and antimatter research, using the Moon as a source of helium-3 fusion fuel, and manufacturing perfect fusion targets. In addition, nuclear technologies can be used to reduce risk and costs of the Space Exploration Initiative. 1 fig.

  5. Atoms for space

    International Nuclear Information System (INIS)

    Buden, D.

    1990-10-01

    Nuclear technology offers many advantages in an expanded solar system space exploration program. These cover a range of possible applications such as power for spacecraft, lunar and planetary surfaces, and electric propulsion; rocket propulsion for lunar and Mars vehicles; space radiation protection; water and sewage treatment; space mining; process heat; medical isotopes; and self-luminous systems. In addition, space offers opportunities to perform scientific research and develop systems that can solve problems here on Earth. These might include fusion and antimatter research, using the Moon as a source of helium-3 fusion fuel, and manufacturing perfect fusion targets. In addition, nuclear technologies can be used to reduce risk and costs of the Space Exploration Initiative. 1 fig

  6. Ion exchange purification of scandium

    Science.gov (United States)

    Herchenroeder, Laurie A.; Burkholder, Harvey R.

    1990-10-23

    An improvement in purification of scandium through ion exchange chromatography is disclosed in which the oxidation potential of the eluting solution is altered by the addition of potassium chlorate or ammonium chloride so that removal of contaminants is encouraged. The temperature, pH and concentration of the eluent HEDTA are controlled in order to maintain the scandium in the column while minimizing dilution of the scandium band. Recovery of scandium is improved by pumping dilute scandium over the column prior to stripping the scandium and precipitation. This eliminates the HEDTA ion and other monovalent cations contaminating the scandium band. This method maximizes recovery of scandium while maintaining purity.

  7. Scandium Terminal Imido Chemistry.

    Science.gov (United States)

    Lu, Erli; Chu, Jiaxiang; Chen, Yaofeng

    2018-02-20

    Research into transition metal complexes bearing multiply bonded main-group ligands has developed into a thriving and fruitful field over the past half century. These complexes, featuring terminal M═E/M≡E (M = transition metal; E = main-group element) multiple bonds, exhibit unique structural properties as well as rich reactivity, which render them attractive targets for inorganic/organometallic chemists as well as indispensable tools for organic/catalytic chemists. This fact has been highlighted by their widespread applications in organic synthesis, for example, as olefin metathesis catalysts. In the ongoing renaissance of transition metal-ligand multiple-bonding chemistry, there have been reports of M═E/M≡E interactions for the majority of the metallic elements of the periodic table, even some actinide metals. In stark contrast, the largest subgroup of the periodic table, rare-earth metals (Ln = Sc, Y, and lanthanides), have been excluded from this upsurge. Indeed, the synthesis of terminal Ln═E/Ln≡E multiple-bonding species lagged behind that of the transition metal and actinide congeners for decades. Although these species had been pursued since the discovery of a rare-earth metal bridging imide in 1991, such a terminal (nonpincer/bridging hapticities) Ln═E/Ln≡E bond species was not obtained until 2010. The scarcity is mainly attributed to the energy mismatch between the frontier orbitals of the metal and the ligand atoms. This renders the putative terminal Ln═E/Ln≡E bonds extremely reactive, thus resulting in the formation of aggregates and/or reaction with the ligand/environment, quenching the multiple-bond character. In 2010, the stalemate was broken by the isolation and structural characterization of the first rare-earth metal terminal imide-a scandium terminal imide-by our group. The double-bond character of the Sc═N bond was unequivocally confirmed by single-crystal X-ray diffraction. Theoretical investigations revealed the presence

  8. Low temperature heat capacity of scandium and alloys of scandium

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, T. W.E.

    1977-12-01

    The heat capacity of three electrotransport purified scandium samples has been measured from 1 to 20/sup 0/K. The resultant electronic specific heat constant and Debye temperature are 10.337 +- 0.015 mJ/gm-atom K/sup 2/ and 346.7 +- 0.8/sup 0/K respectively, and these values are believed to be truly representative of intrinsic scandium. Alloying studies have also been carried out to investigate the band structure of scandium based on the rigid band model, with zirconium to raise the electron concentration and magnesium to lower it. The results are then compared to the theoretical band structure calculations. Low temperature heat capacity measurements have also been made on some dilute Sc-Fe alloys. An anomaly is observed in the C/T vs. T/sup 2/ plot, but the C vs. T curve shows no evidence of magnetic ordering down to 1/sup 0/K, and electrical resistance measurement from 4 to 0.3/sup 0/K also indicates that no magnetic ordering took place.

  9. Hydrogen atom in phase space

    International Nuclear Information System (INIS)

    Chetouani, L.; Hammann, T.F.

    1987-01-01

    The Hamiltonian of the three-dimensional hydrogen atom is reduced, in parabolic coordinates, to the Hamiltonians of two bidimensional harmonic oscillators, by doing several space-time transformations,separating the movement along the three parabolic directions (ξ,eta,phi), and introducing two auxiliary angular variables psi and psi', 0≤psi, psi'≤2π. The Green's function is developed into partial Green's functions, and expressed in terms of two Green's functions that describe the movements along both the ξ and eta axes. Introducing auxiliary Hamiltonians allows one to calculate the Green's function in the configurational space, via the phase-space evolution function of the two-dimensional harmonic oscillator. The auxiliary variables psi and psi' are eliminated by projection. The thus-obtained Green's function, save for a multiplicating factor, coincides with that calculated following the path-integral formalism

  10. Characterization and excitation behaviour studies of radionuclide (scandium) in glass matrix

    International Nuclear Information System (INIS)

    Rehana, Ishrat; Shahid, K.A.; Husain, S.; Muhammad, Din

    1999-01-01

    Directional movements of bed load in marine sediments are studied using a radioactive tracer, scandium, similar to the natural sediment in the area. Scandium glass prepared for this purpose was analyzed by atomic emission spectrography for quality assurance purposes. A buffer composed of graphite with 5% germanium oxide was used for accurate and reproducible analyses. The role of this buffer in the excitation behavior of scandium and variations in spectral line intensity with respect to various influencing parameters are reported. Volatilization of scandium was observed using the moving plate technique, with a dc-arc as the excitation source

  11. Atomic power in space: A history

    International Nuclear Information System (INIS)

    1987-03-01

    ''Atomic Power in Space,'' a history of the Space Isotope Power Program of the United States, covers the period from the program's inception in the mid-1950s through 1982. Written in non-technical language, the history is addressed to both the general public and those more specialized in nuclear and space technologies. 19 figs., 3 tabs

  12. Atomic Power in Space: A History

    Science.gov (United States)

    1987-03-01

    "Atomic Power in Space," a history of the Space Isotope Power Program of the United States, covers the period from the program's inception in the mid-1950s through 1982. Written in non-technical language, the history is addressed to both the general public and those more specialized in nuclear and space technologies. Interplanetary space exploration successes and achievements have been made possible by this technology, for which there is no known substitue.

  13. Atomic power in space: A history

    Energy Technology Data Exchange (ETDEWEB)

    1987-03-01

    ''Atomic Power in Space,'' a history of the Space Isotope Power Program of the United States, covers the period from the program's inception in the mid-1950s through 1982. Written in non-technical language, the history is addressed to both the general public and those more specialized in nuclear and space technologies. 19 figs., 3 tabs.

  14. Atomic collisions under extreme conditions in space

    International Nuclear Information System (INIS)

    Itikawa, Yukikazu

    1987-01-01

    In space, atoms and molecules are often placed under the extreme conditions which are very difficult to be realized on Earth. For instance, extremely hot and dense plasmas are found in and around various stellar objects (e.g., neutron stars) on one hand and extremely cold and diffuse gases prevail in interstellar space on the other. There is so strong a magnetic field that electron clouds in atoms and molecules are distorted. The study of atomic collisions under the extreme conditions is not only helpful in understanding the astrophysical environment but also reveals new aspects of the physics of atoms and molecules. This paper is an invitation to the study. (References are not exhaustive but only provide a clue with which more details can be found.) (author)

  15. Scandium, yttrium and the lanthanides

    International Nuclear Information System (INIS)

    Hart, F.A.

    1987-01-01

    This chapter on the chemistry of the coordination complexes of scandium, yttrium and the lanthanides includes sections on the nitrogen and oxygen donor ligands and complex halides of scandium, and the phosphorus and sulfur donor ligands of yttrium and the lanthanides. Complexes with the macrocylic ligands and with halides are also discussed. Sections on the NMR and electronic spectra of the lanthanides are also included. (UK)

  16. Incommensurate composite crystal structure of scandium-II

    International Nuclear Information System (INIS)

    Fujihisa, Hiroshi; Gotoh, Yoshito; Yamawaki, Hiroshi; Sakashita, Mami; Takeya, Satoshi; Honda, Kazumasa; Akahama, Yuichi; Kawamura, Haruki

    2005-01-01

    The long-unknown crystal structure of the high pressure phase scandium-II was solved by powder x-ray diffraction and was found to have tetragonal host channels along the c axis and guest chains that are incommensurate with the host, as well as the high pressure phases of Ba, Sr, Bi, and Sb. The pressure dependences of the lattice constants, the incommensurability, the atomic distances, and the atomic volume were investigated

  17. Stability constants of scandium complexes, 1

    International Nuclear Information System (INIS)

    Itoh, Hisako; Itoh, Naomi; Suzuki, Yasuo

    1984-01-01

    The stability constants of scandium complexes with some carboxylate ligands were determined potentiometrically at 25.0 and 40.0 0 C and at an ionic strength of 0.10 with potassium nitrate as supporting electrolyte. The constants of the scandium complexes were appreciably greater than those of the corresponding lanthanoid complexes, as expected. The changes in free energy, enthalpy, and entropy for the formation of the scandium complexes were calculated from the stability constants at two temperatures. (author)

  18. Copper scandium zirconium phosphate

    DEFF Research Database (Denmark)

    Bond, Andrew David; Warner, Terence Edwin

    2013-01-01

    The title compound, with nominal formula Cu(2)ScZr(PO(4))(3), has a beige coloration and displays fast Cu(+) cation conduction at elevated temperatures. It adopts a NASICON-type structure in the space group R3c. The examined crystal was an obverse-reverse twin with approximately equal twin compon...

  19. Atomic fine structure in a space of constant curvature

    International Nuclear Information System (INIS)

    Bessis, N.; Bessis, G.; Shamseddine, R.

    1982-01-01

    As a contribution to a tentative formulation of atomic physics in a curved space, the determination of atomic fine structure energies in a space of constant curvature is investigated. Starting from the Dirac equation in a curved space-time, the analogue of the Pauli equation in a general coordinate system is derived. The theoretical curvature induced shifts and splittings of the fine structure energy levels are put in evidence and examined for the particular case of the hydrogenic n=2 levels. (author)

  20. The effects of aluminum or scandium on the toughness, density and ...

    African Journals Online (AJOL)

    The effects of the substitution of aluminum or scandium on the density, toughness as well as the stability of the phases formed by such an addition on platinum, iridium, rhodium and palladium metals were evaluated with the density functional quantum mechanical calculation methods. All the metals had four atoms per ...

  1. Extraction of scandium by organic substance melts

    International Nuclear Information System (INIS)

    Gladyshev, V.P.; Lobanov, F.I.; Zebreva, A.I.; Andreeva, N.N.; Manuilova, O.A.; Il'yukevich, Yu.A.

    1984-01-01

    Regularities of scandium extraction by the melts of octadecanicoic acid, n-carbonic acids of C 17 -C 20 commerical fraction and mixtures of tributylphosphate (TBP) with paraffin at (70+-1) deg C have been studied. The optimum conditions for scandium extraction in the melt of organic substances are determined. A scheme of the extraction by the melts of higher carbonic acids at ninitial metal concentrations of 10 -5 to 10 -3 mol/l has been suggested. The scandium compound has been isolated in solid form, its composition having been determined. The main advantages of extraction by melts are as follows: a possibility to attain high distribution coefficients, distinct separation of phases after extraction, the absence of emulsions, elimination of employing inflammable and toxic solvents, a possibility of rapid X-ray fluorescence determinatinon of scandium directly in solid extract

  2. Scandium, yttrium and the lanthanide metals

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    The hydroxide and oxide phases that exist for scandium(III) include scandium hydroxide, which likely has both amorphous and crystalline forms, ScOOH(s), and scandium oxide. This chapter presents the data selected for the stability constants of the polymeric hydrolysis species of scandium at zero ionic strength. The behaviour of yttrium, and the lanthanide metals, in the environment is largely dependent on their solution equilibria. Hydrolysis and other complexation reactions of yttrium and the lanthanide metals are important in the disposal of nuclear waste. The trivalent lanthanide metals include lanthanum(III) through lutetium(III). A number of studies have reported a tetrad effect for the geochemical behaviour of the lanthanide series, including stability constants and distribution coefficients. The solubility of many of the lanthanide hydroxide phases has been studied at fixed ionic strength. In studying the hydrolysis of cerium(IV), a number of studies have utilised oxidation-reduction reactions in determining the relevant stability constants.

  3. Extraction of scandium by aromatic carboxylic acids

    International Nuclear Information System (INIS)

    Kamenev, V.F.; Fadeeva, V.I.

    1977-01-01

    Extraction of complex compounds af scandium with salicylic, phenyl- and diphenylacetic acids with chloroform solutions of tetraethyldiamideheptylphosphate as a donor-active additive in relation to the pH and reagent concentration has been studied. Extraction of salicylates of some elements (Ta, Nb, Zr, Hf, Mo) by solutions of tetraethyldiamideheptylphosphate in chloroform has been investigated, and the possibility of their extraction separation from scandium is shown

  4. Extraction of scandium by aromatic carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Kamenev, V F; Fadeeva, V I [Moskovskij Gosudarstvennyj Univ. (USSR)

    1977-04-01

    Extraction of complex compounds af scandium with salicylic, phenyl- and diphenylacetic acids with chloroform solutions of tetraethyldiamideheptylphosphate as a donor-active additive in relation to the pH and reagent concentration has been studied. Extraction of salicylates of some elements (Ta, Nb, Zr, Hf, Mo) by solutions of tetraethyldiamideheptylphosphate in chloroform has been investigated, and the possibility of their extraction separation from scandium is shown.

  5. Precision Gravity Tests with Atom Interferometry in Space

    Energy Technology Data Exchange (ETDEWEB)

    Tino, G.M.; Sorrentino, F. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Aguilera, D. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Battelier, B.; Bertoldi, A. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Bodart, Q. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Bongs, K. [Midlands Ultracold Atom Research Centre School of Physics and Astronomy University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Bouyer, P. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Braxmaier, C. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Cacciapuoti, L. [European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Gaaloul, N. [Institute of Quantum Optics, Leibniz Universitaet Hannover, Welfengarten 1, D 30167 Hannover (Germany); Gürlebeck, N. [University of Bremen, Centre of Applied Space Technology and Microgravity (ZARM), Am Fallturm, D - 29359 Bremen (Germany); Hauth, M. [Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); and others

    2013-10-15

    Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual {sup 85}Rb-{sup 87}Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments.

  6. A basic evaluated neutronic data file for elemental scandium

    International Nuclear Information System (INIS)

    Smith, A.B.; Meadows, J.W.; Howerton, R.J.

    1992-01-01

    This report documents an evaluated neutronic data file for elemental scandium, presented in the ENDF/B-VI format. This file should provide basic nuclear data essential for neutronic calculations involving elemental scandium. No equivalent file was previously available

  7. Diagrammatic Representation of Electronic Correlations in Photoionization Process: Application to Scandium

    International Nuclear Information System (INIS)

    Liu Mengmeng; Ma Xiaoguang

    2011-01-01

    The conversion rules under which an algebraic expression can be obtained from a corresponding photoionization Goldstone diagram have been given systematically in the present work. The electronic correlations in the photoionization processes then could be studied diagrammatically. The application to atomic scandium shows that the present theoretical scheme can give reasonable photoionization cross sections, which agree well with the experimental results. (atomic and molecular physics)

  8. Relativistic quantum similarities in atoms in position and momentum spaces

    International Nuclear Information System (INIS)

    Maldonado, P.; Sarsa, A.; Buendia, E.; Galvez, F.J.

    2011-01-01

    A study of different quantum similarity measures and their corresponding quantum similarity indices is carried out for the atoms from H to Lr (Z=1-103). Relativistic effects in both position and momentum spaces have been studied by comparing the relativistic values to the non-relativistic ones. We have used the atomic electron density in both position and momentum spaces obtained within relativistic and non-relativistic numerical-parameterized optimized effective potential approximations. -- Highlights: → Quantum similarity measures and indices in electronic structure of atoms. → Position and momentum electronic densities. → Similarity of relativistic and non-relativistic densities. → Similarity of core and valence regions of different atoms. → Dependence with Z along the Periodic Table.

  9. Relativistic Hydrogen-Like Atom on a Noncommutative Phase Space

    Science.gov (United States)

    Masum, Huseyin; Dulat, Sayipjamal; Tohti, Mutallip

    2017-09-01

    The energy levels of hydrogen-like atom on a noncommutative phase space were studied in the framework of relativistic quantum mechanics. The leading order corrections to energy levels 2 S 1/2, 2 P 1/2 and 2 P 3/2 were obtained by using the 𝜃 and the \\bar θ modified Dirac Hamiltonian of hydrogen-like atom on a noncommutative phase space. The degeneracy of the energy levels 2 P 1/2 and 2 P 3/2 were removed completely by 𝜃-correction. And the \\bar θ -correction shifts these energy levels.

  10. Dirac equation in noncommutative space for hydrogen atom

    Energy Technology Data Exchange (ETDEWEB)

    Adorno, T.C., E-mail: tadorno@nonada.if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05508-090 Sao Paulo, SP (Brazil); Baldiotti, M.C., E-mail: baldiott@fma.if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05508-090 Sao Paulo, SP (Brazil); Chaichian, M., E-mail: Masud.Chaichian@helsinki.f [Department of Physics, University of Helsinki and Helsinki Institute of Physics, PO Box 64, FIN-00014 Helsinki (Finland); Gitman, D.M., E-mail: gitman@dfn.if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05508-090 Sao Paulo, SP (Brazil); Tureanu, A., E-mail: Anca.Tureanu@helsinki.f [Department of Physics, University of Helsinki and Helsinki Institute of Physics, PO Box 64, FIN-00014 Helsinki (Finland)

    2009-11-30

    We consider the energy levels of a hydrogen-like atom in the framework of theta-modified, due to space noncommutativity, Dirac equation with Coulomb field. It is shown that on the noncommutative (NC) space the degeneracy of the levels 2S{sub 1/2}, 2P{sub 1/2} and 2P{sub 3/2} is lifted completely, such that new transition channels are allowed.

  11. Dirac equation in noncommutative space for hydrogen atom

    International Nuclear Information System (INIS)

    Adorno, T.C.; Baldiotti, M.C.; Chaichian, M.; Gitman, D.M.; Tureanu, A.

    2009-01-01

    We consider the energy levels of a hydrogen-like atom in the framework of θ-modified, due to space noncommutativity, Dirac equation with Coulomb field. It is shown that on the noncommutative (NC) space the degeneracy of the levels 2S 1/2 , 2P 1/2 and 2P 3/2 is lifted completely, such that new transition channels are allowed.

  12. Observation of dynamic atom-atom correlation in liquid helium in real space.

    Science.gov (United States)

    Dmowski, W; Diallo, S O; Lokshin, K; Ehlers, G; Ferré, G; Boronat, J; Egami, T

    2017-05-04

    Liquid 4 He becomes superfluid and flows without resistance below temperature 2.17 K. Superfluidity has been a subject of intense studies and notable advances were made in elucidating the phenomenon by experiment and theory. Nevertheless, details of the microscopic state, including dynamic atom-atom correlations in the superfluid state, are not fully understood. Here using a technique of neutron dynamic pair-density function (DPDF) analysis we show that 4 He atoms in the Bose-Einstein condensate have environment significantly different from uncondensed atoms, with the interatomic distance larger than the average by about 10%, whereas the average structure changes little through the superfluid transition. DPDF peak not seen in the snap-shot pair-density function is found at 2.3 Å, and is interpreted in terms of atomic tunnelling. The real space picture of dynamic atom-atom correlations presented here reveal characteristics of atomic dynamics not recognized so far, compelling yet another look at the phenomenon.

  13. Method for chromatographically recovering scandium and yttrium

    International Nuclear Information System (INIS)

    Snyder, T.S.; Stoltz, R.A.

    1991-01-01

    This paper describes a method for chromatographically recovering scandium and yttrium from the residue of a sand chlorinator. It comprises: providing a residue from a sand chlorinator, the residue containing scandium, yttrium, sodium, calcium and at least one radioactive metal of the group consisting of radium, thorium and uranium; digesting the residue with an acid to produce an aqueous liquid containing scandium, yttrium, sodium, calcium and at least one radioactive metal of the group consisting of radium, thorium and uranium; feeding the metal containing liquid through a cation exchanger; eluding the cation exchanger with an acid eluant to to produce: a first eluate containing at least half of the total weight of the calcium and sodium in the feed liquid; a second eluate containing at least half of the total weight of the one or more radioactive metals in the feed liquid; a third eluate containing at least half of the yttrium in the feed liquid, and a fourth eluate containing at least half of the weight of the scandium in the feed liquid

  14. Automated Construction of Molecular Active Spaces from Atomic Valence Orbitals.

    Science.gov (United States)

    Sayfutyarova, Elvira R; Sun, Qiming; Chan, Garnet Kin-Lic; Knizia, Gerald

    2017-09-12

    We introduce the atomic valence active space (AVAS), a simple and well-defined automated technique for constructing active orbital spaces for use in multiconfiguration and multireference (MR) electronic structure calculations. Concretely, the technique constructs active molecular orbitals capable of describing all relevant electronic configurations emerging from a targeted set of atomic valence orbitals (e.g., the metal d orbitals in a coordination complex). This is achieved via a linear transformation of the occupied and unoccupied orbital spaces from an easily obtainable single-reference wave function (such as from a Hartree-Fock or Kohn-Sham calculations) based on projectors to targeted atomic valence orbitals. We discuss the premises, theory, and implementation of the idea, and several of its variations are tested. To investigate the performance and accuracy, we calculate the excitation energies for various transition-metal complexes in typical application scenarios. Additionally, we follow the homolytic bond breaking process of a Fenton reaction along its reaction coordinate. While the described AVAS technique is not a universal solution to the active space problem, its premises are fulfilled in many application scenarios of transition-metal chemistry and bond dissociation processes. In these cases the technique makes MR calculations easier to execute, easier to reproduce by any user, and simplifies the determination of the appropriate size of the active space required for accurate results.

  15. Atom interferometry in space: Thermal management and magnetic shielding

    Energy Technology Data Exchange (ETDEWEB)

    Milke, Alexander; Kubelka-Lange, André; Gürlebeck, Norman, E-mail: norman.guerlebeck@zarm.uni-bremen.de; Rievers, Benny; Herrmann, Sven [Center of Applied Space Technology and Microgravity (ZARM), University Bremen, Am Fallturm, 28359 Bremen (Germany); Schuldt, Thilo [DLR Institute for Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Braxmaier, Claus [Center of Applied Space Technology and Microgravity (ZARM), University Bremen, Am Fallturm, 28359 Bremen (Germany); DLR Institute for Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany)

    2014-08-15

    Atom interferometry is an exciting tool to probe fundamental physics. It is considered especially apt to test the universality of free fall by using two different sorts of atoms. The increasing sensitivity required for this kind of experiment sets severe requirements on its environments, instrument control, and systematic effects. This can partially be mitigated by going to space as was proposed, for example, in the Spacetime Explorer and Quantum Equivalence Principle Space Test (STE-QUEST) mission. However, the requirements on the instrument are still very challenging. For example, the specifications of the STE-QUEST mission imply that the Feshbach coils of the atom interferometer are allowed to change their radius only by about 260 nm or 2.6 × 10{sup −4} % due to thermal expansion although they consume an average power of 22 W. Also Earth's magnetic field has to be suppressed by a factor of 10{sup 5}. We show in this article that with the right design such thermal and magnetic requirements can indeed be met and that these are not an impediment for the exciting physics possible with atom interferometers in space.

  16. Spontaneous emergence of free-space optical and atomic patterns

    International Nuclear Information System (INIS)

    Schmittberger, Bonnie L; Gauthier, Daniel J

    2016-01-01

    The spontaneous formation of patterns in dynamical systems is a rich phenomenon that transcends scientific boundaries. Here, we report our observation of coupled optical–atomic pattern formation, which results in the creation of self-organized, multimode structures in free-space laser-driven cold atoms. We show that this process gives rise to spontaneous three-dimensional Sisyphus cooling even at very low light intensities and the emergence of self-organized structures on both sub- and super-wavelength scales. (paper)

  17. Two-step photoionization of hydrogen atoms in interplanetary space

    International Nuclear Information System (INIS)

    Gruntman, M.A.

    1990-01-01

    Photoionization is one of the key processes which determine the properties of fluxes of neutral atoms in interplanetary space. A new two-step channel (called indirect) of photoionization of hydrogen atoms is proposed. Hydrogen atoms are at first excited to states with principal quantum number n > 2, then decay to metastable H(2S) states, where they can be photoionized. Competing processes due to the interaction with solar wind plasma and solar radiation are considered and the photoionization rate through the proposed indirect channel is calculated. This rate depends on distance from the Sun as ∝ 1/R 4 at large distances (R > 1-2 a.u.) and as ∝ 1/R 2 at close approaches, where it is higher than the rate of direct photoionization. (author)

  18. PHARAO space atomic clock: new developments on the laser source

    Science.gov (United States)

    Saccoccio, Muriel; Loesel, Jacques; Coatantiec, Claude; Simon, Eric; Laurent, Philippe; Lemonde, Pierre; Maksimovic, I.; Abgrall, M.

    2017-11-01

    The PHARAO project purpose is to open the way for a new atomic clock generation in space, where laser cooling techniques and microgravity allow high frequency stability and accuracy. The French space agency, CNES is funding and managing the clock construction. The French SYRTE and LKB laboratories are scientific and technical advisers for the clock requirements and the follow-up of subsystem development in industrial companies. EADS SODERN is developing two main subsystems of the PHARAO clock: the Laser Source and the Cesium Tube where atoms are cooled, launched, selected and detected by laser beams. The Laser Source includes an optical bench and electronic devices to generate the laser beams required. This paper describes PHARAO and the role laser beams play in its principle of operation. Then we present the Laser Source design, the technologies involved, and the status of development. Lastly, we focus of a key equipment to reach the performances expected, which is the Extended Cavity Laser Diode.

  19. Applications of atom interferometry - from ground to space

    Science.gov (United States)

    Schubert, Christian; Rasel, Ernst Maria; Gaaloul, Naceur; Ertmer, Wolfgang

    2016-07-01

    Atom interferometry is utilized for the measurement of rotations [1], accelerations [2] and for tests of fundamental physics [3]. In these devices, three laser light pulses separated by a free evolution time coherently manipulate the matter waves which resembles the Mach-Zehnder geometry in optics. Atom gravimeters demonstrated an accuracy of few microgal [2,4], and atom gradiometers showed a noise floor of 30 E Hz^{-1/2} [5]. Further enhancements of atom interferometers are anticipated by the integration of novel source concepts providing ultracold atoms, extending the free fall time of the atoms, and enhanced techniques for coherent manipulation. Sources providing Bose-Einstein condensates recently demontrated a flux compatible with precision experiments [6]. All of these aspects are studied in the transportable quantum gravimeter QG-1 and the very long baseline atom interferometry teststand in Hannover [7] with the goal of surpassing the microgal regime. Going beyond ground based setups, the QUANTUS collaboration exploits the unique features of a microgravity environment in drop tower experiments [8] and in a sounding rocket mission. The payloads are compact and robust atom optics experiments based on atom chips [6], enabling technology for transportable sensors on ground as a byproduct. More prominently, they are pathfinders for proposed satellite missions as tests of the universality of free fall [9] and gradiometry based on atom interferometers [10]. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM1552-1557 (QUANTUS-IV-Fallturm) and by the Deutsche Forschungsgemeinschaft in the framework of the SFB 1128 geo-Q. [1] PRL 114 063002 2015 [2] Nature 400 849 1999 [3] PRL 112 203002 2014 [4] NJP 13 065026 2011 [5] PRA 65 033608 2002 [6] NJP 17 065001 2015 [7] NJP 17 035011 2015 [8] PRL 110 093602 2013 [9

  20. Efficient Means of Detecting Neutral Atoms in Space

    Science.gov (United States)

    Zinicola, W. N.

    2006-12-01

    This summer, The Society of Physics Students granted me the opportunity to participate in an internship for The National Aeronautics and Space Administration (NASA) and The University of Maryland. Our chief interest was analyzing low energy neutral atoms that were created from random interactions of ions in space plasma. From detecting these neutrals one can project a image of what the plasma's composition is, and how this plasma changes through interactions with the solar wind. Presently, low energy neutral atom detectors have poor efficiency, typically in the range of 1%. Our goal was to increase this efficiency. To detect low energy neutrals we must first convert them from neutral molecules to negatively charged ions. Once converted, these "new" negatively charged ions can be easily detected and completely analyzed giving us information about their energy, mass, and instantaneous direction. The efficiency of the detector is drastically affected by the surface used for converting these neutrals. My job was first to create thin metal conversion surfaces. Then, using an X-ray photoelectron spectrometer, analyze atomic surface composition and gather work function values. Once the work function values were known we placed the surfaces in our neutral detector and measured their conversion efficiencies. Finally, a relation between the work function of the metal surface an its conversion efficiency was generated. With this relationship accurately measured one could use this information to help give suggestions on what surface would be the best to increase our detection efficiency. If we could increase the efficiency of these low energy neutral atom detectors by even 1% we would be able to decrease the size of the detector therefore making it cheaper and more applicable for space exploration.* * A special thanks to Dr. Michael Coplan of the University of Maryland for his support and guidance through all my research.

  1. Complexometric determination of scandium and aluminium

    International Nuclear Information System (INIS)

    Tikhonov, V.N.

    1980-01-01

    Described is the complexometric determination of scandium and aluminium by the method of reverse titration of EDTA excess by indium salt solution in the presence of the xylenol orange indicator. For the method selectivity increase fluorides are used as a camouflage substance at low pH values (2.5-3.0). The excess fluoride-ions preventing titration are bound by boric acid. Y, Tb, Ti, Zr, Cu, Zn, V, Mo, Co, Cr prevent the determination of Sc and Al

  2. Mercury Atomic Frequency Standards for Space Based Navigation and Timekeeping

    Science.gov (United States)

    Tjoelker, R. L.; Burt, E. A.; Chung, S.; Hamell, R. L.; Prestage, J. D.; Tucker, B.; Cash, P.; Lutwak, R.

    2012-01-01

    A low power Mercury Atomic Frequency Standard (MAFS) has been developed and demonstrated on the path towards future space clock applications. A self contained mercury ion breadboard clock: emulating flight clock interfaces, steering a USO local oscillator, and consuming approx 40 Watts has been operating at JPL for more than a year. This complete, modular ion clock instrument demonstrates that key GNSS size, weight, and power (SWaP) requirements can be achieved while still maintaining short and long term performance demonstrated in previous ground ion clocks. The MAFS breadboard serves as a flexible platform for optimizing further space clock development and guides engineering model design trades towards fabrication of an ion clock for space flight.

  3. Few helium atoms in quasi two-dimensional space

    International Nuclear Information System (INIS)

    Kilic, Srecko; Vranjes, Leandra

    2003-01-01

    Two, three and four 3 He and 4 He atoms in quasi two-dimensional space above graphite and cesium surfaces and in 'harmonic' potential perpendicular to the surface have been studied. Using some previously examined variational wave functions and the Diffusion Monte Carlo procedure, it has been shown that all molecules: dimers, trimers and tetramers, are bound more strongly than in pure two- and three-dimensional space. The enhancement of binding with respect to unrestricted space is more pronounced on cesium than on graphite. Furthermore, for 3 He 3 ( 3 He 4 ) on all studied surfaces, there is an indication that the configuration of a dimer and a 'free' particle (two dimers) may be equivalently established

  4. Atom Interferometry for Fundamental Physics and Gravity Measurements in Space

    Science.gov (United States)

    Kohel, James M.

    2012-01-01

    Laser-cooled atoms are used as freefall test masses. The gravitational acceleration on atoms is measured by atom-wave interferometry. The fundamental concept behind atom interferometry is the quantum mechanical particle-wave duality. One can exploit the wave-like nature of atoms to construct an atom interferometer based on matter waves analogous to laser interferometers.

  5. Ternary scandium and transition metals germanides

    International Nuclear Information System (INIS)

    Kotur, B.Ya.

    1992-01-01

    Brief review of data on phase diagram of ternary Sc-Me-Ge systems (Me-d - , f-transition element) is given. Isothermal sections at 870 and 1070 K of 17 ternary systems are plotted. Compositions and their structural characteristics are presented. Variability of crystal structure is typical for ternary scandium germanides: 70 compounds with the studied structure belong to 23 structural types. Ternary germanides isostructural to types of Sm 4 Ge 4 , ZrCrSi 2 , ZrNiAl, ScCeSi, TiNiSi U 4 Re 7 Si 6 145 compounds from 70 under investigation are mostly formed in studied systems

  6. Extraction of scandium salicylate by tetraethyldiamidoheptyl phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Kamenev, V F; Fadeeva, V I; Zyk, N V [Moskovskij Gosudarstvennyj Univ. (USSR). Kafedra Analiticheskoj Khimii

    1976-11-01

    Scandium salicylate is extracted with chloroform in a narrow pH range 3-4 and at the maximum concentration of salicylic acid (H/sub 2/A) in an organic phase, the distribution coefficient reaches 0.1. In the presence of tetraethyldiamideheptylphosphate (DAHP) the zone of maximum extraction grows and the distribution coefficient increases. The ratio of the components in the complex extracted is Sc:H/sub 2/A:DAHPh=1:3:2. The extraction constant is Ksub(ex)=(2.00+-0.02).

  7. A novel boron-rich quaternary scandium borocarbosilicide Sc3.67-xB41.4-y-zC0.67+zSi0.33-w

    International Nuclear Information System (INIS)

    Tanaka, Takaho; Yamamoto, Akiji; Sato, Akira

    2004-01-01

    A novel quaternary scandium borocarbosilicide Sc 3.67-x B 41.4-y-z C 0.67+z Si 0.33-w was found. Single crystallites were obtained as an intergrowth phase in the float-zoned single crystal of Sc 0.83-x B 10.0-y C 0.17+y Si 0.083-z that has a face-centered cubic crystal structure. Single crystal structure analysis revealed that the compound has a hexagonal structure with lattice constants a = b = 1.43055(8) nm and c = 2.37477(13) nm and space group P6-barm2 (No. 187). The crystal composition calculated from the structure analysis for the crystal with x = 0.52, y = 1.42, z = 1.17, and w = 0.02 was ScB 12.3 C 0.58 Si 0.10 and that agreed rather well with the composition of ScB 11.5 C 0.61 Si 0.04 measured by EPMA. In the crystal structure that is a new structure type of boron-rich borides, there are 79 structurally independent atomic sites, 69 boron and/or carbon sites, two silicon sites and eight scandium sites. Boron and carbon form seven structurally independent B 12 icosahedra, one B 9 polyhedron, one B 10 polyhedron, one irregularly shaped B 16 polyhedron in which only 10.7 boron atoms are available because of partial occupancies and 10 bridging sites. All polyhedron units and bridging site atoms interconnect each other forming a three-dimensional boron framework structure. Sc atoms reside in the open spaces in the boron framework structure

  8. Scandium: its occurrence, chemistry, physics, metallurgy, biology, and technology

    International Nuclear Information System (INIS)

    Horovitz, C.T.

    1975-01-01

    This book describes the following aspects of scandium: discovery and history, occurrence in nature, geochemistry and mineralogy, chemical, physical and technological properties, fabrication and metallurgy, its biological significance and toxicology, and its uses. (Extensive references for each chapter)

  9. Accelerometer for Space Applications Based on Light-Pulse Atom Interferometry, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to build a compact, high-precision single-axis accelerometer based on atom interferometry that is applicable to operation in space environments. Based on...

  10. Hydrogen atom in phase space: the Wigner representation

    International Nuclear Information System (INIS)

    Praxmeyer, Ludmila; Mostowski, Jan; Wodkiewicz, Krzysztof

    2006-01-01

    The hydrogen atom is a fundamental exactly soluble system for which the Wigner function, being a quantum analogue of the joint probability distribution of position and momentum, is unknown. In this paper, we present an effective method of calculating the Wigner function, for all bound states of the nonrelativistic hydrogen atom. The formal similarity between the eigenfunctions of the nonrelativistic hydrogen atom in the momentum representation and the Klein-Gordon propagator has allowed the calculation of the Wigner function for an arbitrary bound state of the hydrogen atom, using a simple atomic integral as a generator. These Wigner functions for some low-lying states are depicted and discussed

  11. Interaction of scandium sesquioxide with carbon

    International Nuclear Information System (INIS)

    Vodop'yanov, A.G.; Zakharov, R.G.

    1986-01-01

    In the range of 2350-2470 degrees K at a PCO = 0.0 MPa, interaction in Sc 2 O 3 with carbon mixtures initially occurs by CO chemisorption at the scandium oxide surface and disproportionation into CO 2 and C, with subsequent replacement of oxygen in the oxide anion sublattice by carbon to form ScC. The carbide melt, creating a contact between the reagents, then transforms the process to a diffusion-based one. At 1820-2220 K in vacuum, reduction of the studied mixtures occurs by dissociative vaporization of the oxide, with precipitation of ScC at the carbon surface and generation of CO. The appearance of CO in the vapors of mixture leads to formation of an oxycarbide phase and to the partial occurrence of oxide dissociation

  12. The crystal structure of scandium dyhydrate triglycolate

    International Nuclear Information System (INIS)

    Dukareva, L.M.; Antishkina, A.S.; Porai-Koshits, M.A.; Ostrikova, V.N.; Arkhangel'skij, I.V.; Amanov, A.Z.

    1978-01-01

    The structure of colorless crystals of scandium glycolate dehydrate Sc(CH 2 OHCOO) 3 x2H 2 O, synthesized at the chemical department of MSU has been investigated. Parameters of the monoclinic lattice are determined according to roentgenograms of swing and Kforograms and are specified using the DRON-1 diffractor: a=14.624-+0.005 A; b=13.052-+0.003 A; c=5.730+-0.003 A; γ=96.26 deg+-0.01 deg; rhosub(exper.)=1.09 g/cm 3 ; Z=4; Sp.=P 2/b. Experimental photographic data are obtained using the KFOR chamber. Scannings of the layer lines h anti Ko-h anti K4, containing 742 independent reflexes are taken. Deciphering of the structure is carried out by means of analysis of the Paterson functions distribution and conventional and differential electron densities. Description of the system is presented

  13. Thermodynamic and kinetic study of scandium(III) complexes of DTPA and DOTA: a step toward scandium radiopharmaceuticals.

    Science.gov (United States)

    Pniok, Miroslav; Kubíček, Vojtěch; Havlíčková, Jana; Kotek, Jan; Sabatie-Gogová, Andrea; Plutnar, Jan; Huclier-Markai, Sandrine; Hermann, Petr

    2014-06-23

    Diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) scandium(III) complexes were investigated in the solution and solid state. Three (45)Sc NMR spectroscopic references suitable for aqueous solutions were suggested: 0.1 M Sc(ClO4)3 in 1 M aq. HClO4 (δSc =0.0 ppm), 0.1 M ScCl3 in 1 M aq. HCl (δSc =1.75 ppm) and 0.01 M [Sc(ox)4](5-) (ox(2-) = oxalato) in 1 M aq. K2C2O4 (δSc =8.31 ppm). In solution, [Sc(dtpa)](2-) complex (δSc = 83 ppm, Δν = 770 Hz) has a rather symmetric ligand field unlike highly unsymmetrical donor atom arrangement in [Sc(dota)](-) anion (δSc = 100 ppm, Δν = 4300 Hz). The solid-state structure of K8[Sc2(ox)7]⋅13 H2O contains two [Sc(ox)3](3-) units bridged by twice "side-on" coordinated oxalate anion with Sc(3+) ion in a dodecahedral O8 arrangement. Structures of [Sc(dtpa)](2-) and [Sc(dota)](-) in [(Hguanidine)]2[Sc(dtpa)]⋅3 H2O and K[Sc(dota)][H6 dota]Cl2⋅4 H2O, respectively, are analogous to those of trivalent lanthanide complexes with the same ligands. The [Sc(dota)](-) unit exhibits twisted square-antiprismatic arrangement without an axial ligand (TSA' isomer) and [Sc(dota)](-) and (H6 dota)(2+) units are bridged by a K(+) cation. A surprisingly high value of the last DOTA dissociation constant (pKa =12.9) was determined by potentiometry and confirmed by using NMR spectroscopy. Stability constants of scandium(III) complexes (log KScL 27.43 and 30.79 for DTPA and DOTA, respectively) were determined from potentiometric and (45)Sc NMR spectroscopic data. Both complexes are fully formed even below pH 2. Complexation of DOTA with the Sc(3+) ion is much faster than with trivalent lanthanides. Proton-assisted decomplexation of the [Sc(dota)](-) complex (τ1/2 =45 h; 1 M aq. HCl, 25 °C) is much slower than that for [Ln(dota)](-) complexes. Therefore, DOTA and its derivatives seem to be very suitable ligands for scandium

  14. Bonding in scandium monosulfide a NaCl crystal type

    International Nuclear Information System (INIS)

    Merrick, J.A.

    1980-08-01

    The transition temperature of an order-disorder transition in Sc 0 81 S (R anti 3m to Fm3m) occurs at 700 0 C. A group of ordered sublattices on the NaCl-type lattice (Fm3m) was generated and a Madelung energy and configurational entropy were calculated for each sublattice assuming the ions to be Sc 2 48+ and S 2- . Mean field and pair interaction approximations were used to model long-range and short-range orderings, respectively. The electrostatic model fails to predict the observed short-range and long-range orderings. The high temperature vaporization of ScP was investigated by mass spectrometry and target collection Knudsen effusion at 1767 to 2209K. The composition ScP 1 00 vaporizes congruently to the gaseous species Sc, P, and P 2 . A temperature independent third law enthalpy of atomization (ΔH 0 /sub atom,298/ = 252.2 +- 2.8 kcal mole -1 ) has a value approx. 12 kcal larger than that reported for ScS. Nonrelativistic, nonself-consistent LAPW band structure calculations are reported for ScS. XPS and UPS measurements are reported for Sc 2 S 3 and several compositions Sc/sub 1-x/S (0.0 less than or equal to x less than or equal to 0.2). The Sc and S 2p binding energies (XPS) obtained for the defect scandium monosulfides are very close to those found in the pure elements, suggesting covalent bonding. The Sc 2p energy region has an interesting satellite structure

  15. Wigner’s phase-space function and atomic structure: II. Ground states for closed-shell atoms

    DEFF Research Database (Denmark)

    Springborg, Michael; Dahl, Jens Peder

    1987-01-01

    We present formulas for reduced Wigner phase-space functions for atoms, with an emphasis on the first-order spinless Wigner function. This function can be written as the sum of separate contributions from single orbitals (the natural orbitals). This allows a detailed study of the function. Here we...... display and analyze the function for the closed-shell atoms helium, beryllium, neon, argon, and zinc in the Hartree-Fock approximation. The quantum-mechanical exact results are compared with those obtained with the approximate Thomas-Fermi description of electron densities in phase space....

  16. Lifetime measurements and oscillator strengths in singly ionized scandium and the solar abundance of scandium

    Science.gov (United States)

    Pehlivan Rhodin, A.; Belmonte, M. T.; Engström, L.; Lundberg, H.; Nilsson, H.; Hartman, H.; Pickering, J. C.; Clear, C.; Quinet, P.; Fivet, V.; Palmeri, P.

    2017-12-01

    The lifetimes of 17 even-parity levels (3d5s, 3d4d, 3d6s and 4p2) in the region 57 743-77 837 cm-1 of singly ionized scandium (Sc II) were measured by two-step time-resolved laser induced fluorescence spectroscopy. Oscillator strengths of 57 lines from these highly excited upper levels were derived using a hollow cathode discharge lamp and a Fourier transform spectrometer. In addition, Hartree-Fock calculations where both the main relativistic and core-polarization effects were taken into account were carried out for both low- and high-excitation levels. There is a good agreement for most of the lines between our calculated branching fractions and the measurements of Lawler & Dakin in the region 9000-45 000 cm-1 for low excitation levels and with our measurements for high excitation levels in the region 23 500-63 100 cm-1. This, in turn, allowed us to combine the calculated branching fractions with the available experimental lifetimes to determine semi-empirical oscillator strengths for a set of 380 E1 transitions in Sc II. These oscillator strengths include the weak lines that were used previously to derive the solar abundance of scandium. The solar abundance of scandium is now estimated to logε⊙ = 3.04 ± 0.13 using these semi-empirical oscillator strengths to shift the values determined by Scott et al. The new estimated abundance value is in agreement with the meteoritic value (logεmet = 3.05 ± 0.02) of Lodders, Palme & Gail.

  17. Highly sensitive luminescence method of scandium determination in the products of metallurgical reprocessing

    International Nuclear Information System (INIS)

    Matveets, M.A.; Akhmetova, S.D.

    1988-01-01

    Highly sensitive reaction of scandium with 1,10-phenanthroline and eosin is used for the development of luminescence method of its determination in metallurgical products. The effect of interfering elements is eliminated by scandium extraction with monocarboxylic acids. The method permits to determine scandium content from 5 x 10 -5 % (Sr 0.15 - 0.25)

  18. Comment on "Wigner phase-space distribution function for the hydrogen atom"

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Springborg, Michael

    1999-01-01

    We object to the proposal that the mapping of the three-dimensional hydrogen atom into a four-dimensional harmonic oscillator can be readily used to determine the Wigner phase-space distribution function for the hydrogen atom. [S1050-2947(99)07005-5].......We object to the proposal that the mapping of the three-dimensional hydrogen atom into a four-dimensional harmonic oscillator can be readily used to determine the Wigner phase-space distribution function for the hydrogen atom. [S1050-2947(99)07005-5]....

  19. Size Effects on Deformation and Fracture of Scandium Deuteride Films.

    Energy Technology Data Exchange (ETDEWEB)

    Teresi, C. S. [Univ. of Minnesota, Minneapolis, MN (United States); Hintsala, E. [Univ. of Minnesota, Minneapolis, MN (United States); Hysitron, Inc., Eden Prairie, MN (United States); Adams, David P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yang, Nancy Y. C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kammler, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moody, N. R. [Univ. of Minnesota, Minneapolis, MN (United States); Gerberich, W. W. [Univ. of Minnesota, Minneapolis, MN (United States)

    2017-07-01

    Metal hydride films have been observed to crack during production and use, prompting mechanical property studies of scandium deuteride films. The following focuses on elastic modulus, fracture, and size effects observed in the system for future film mechanical behavior modeling efforts. Scandium deuteride films were produced through the deuterium charging of electron beam evaporated scandium films using X-ray diffraction, scanning Auger microscopy, and electron backscatter diffraction to monitor changes in the films before and after charging. Scanning electron microscopy, nanoindentation, and focused ion beam machined micropillar compression tests were used for mechanical characterization of the scandium deuteride films. The micropillars showed a size effect for flow stress, indicating that film thickness is a relevant tuning parameter for film performance, and that fracture was controlled by the presence of grain boundaries. Elastic modulus was determined by both micropillar compression and nanoindentation to be approximately 150 GPa, Fracture studies of bulk film channel cracking as well as compression induced cracks in some of the pillars yielded a fracture toughness around 1.0 MPa-m1/2. Preliminary Weibull distributions of fracture in the micropillars are provided. Despite this relatively low value of fracture toughness, scandium deuteride micropillars can undergo a large degree of plasticity in small volumes and can harden to some degree, demonstrating the ductile and brittle nature of this material

  20. Formation of scandium carbides and scandium oxycarbide from the elements at high-(P, T) conditions

    International Nuclear Information System (INIS)

    Juarez-Arellano, Erick A.; Winkler, Bjoern; Bayarjargal, Lkhamsuren; Friedrich, Alexandra; Milman, Victor; Kammler, Daniel R.; Clark, Simon M.; Yan Jinyuan; Koch-Mueller, Monika; Schroeder, Florian; Avalos-Borja, Miguel

    2010-01-01

    Synchrotron diffraction experiments with in situ laser heated diamond anvil cells and multi-anvil press synthesis experiments have been performed in order to investigate the reaction of scandium and carbon from the elements at high-(P,T) conditions. It is shown that the reaction is very sensitive to the presence of oxygen. In an oxygen-rich environment the most stable phase is ScO x C y , where for these experiments x=0.39 and y=0.50-0.56. If only a small oxygen contamination is present, we have observed the formation of Sc 3 C 4 , Sc 4 C 3 and a new orthorhombic ScC x phase. All the phases formed at high pressures and temperatures are quenchable. Experimentally determined elastic properties of the scandium carbides are compared to values obtained by density functional theory based calculations. - Graphical Abstract Legend (TOC Figure): Table of Contents Figure Selected images recorded with a MAR345 image plate detector show the reaction of α-Sc and graphite at high-(P,T) conditions. Left: mixture of α-Sc and graphite. Right: recovered sample after laser heated the diamond anvil cell.

  1. Smelting of Scandium by Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Satoshi Fujii

    2017-09-01

    Full Text Available Scandium is being explored as an alloying element for aluminum alloys, which are gaining importance as high-performance lightweight structural alloys in the transportation industry. A few years ago, Sc was also found to be suitable for use in electrical devices. High-Sc-content ScAlN thin films have attracted significant attention because of their strong piezoelectricity. The piezoelectric response of ScAlN suggests that ScAlN thin films formed on a hard substrate would be suitable surface acoustic wave wideband filters for next-generation wireless communication systems. However, it is often difficult to use ScAlN thin films in MEMS devices—including acoustic ones—because of the extremely high price of metallic Sc, given the difficulty associated with smelting it. Here, we propose a novel process for smelting Sc metal by microwave irradiation. Sc metal was able to be obtained successfully from ScF3 through a microwave-irradiation-based carbon reduction reaction. The reaction temperature for this reduction process was approximately 880°C, which is half of that for the conventional smelting process involving reduction with Ca. Thus, the proposed microwave irradiation process has significant potential for use in the smelting of Sc metal.

  2. Scandium and zirconium ion complexing with salicylic acid

    International Nuclear Information System (INIS)

    Fadeeva, V.I.; Kochetkova, S.K.

    1979-01-01

    A study has been made of the extraction of complexes containing scandium and zirconium compounds and salicylic acid by using benzene, nitrobenzene, chloroform and isoamyl alcohol. It is shown that in the metal concentration range 10 -5 -10 -3 mole/l scandium forms mononuclear complexes composed of Sc(HSal) 3 (pH 2 (pH>4), zirconium - polynuclear complexes Zrsub(x)(OH)sub(y)(HSal)sub(n), where the x:n ratio varies from 0.5 to 1.5. Stability constants have been calculated for the salicylate scandium complexes in aqueous solution, equal to β 1 =(3+-1)x10 2 ; β 2 =(5.0+-0.6)x10 4 ; β 3 =(5.3+-0.3)x10 6

  3. Scandium and zirconium ion complexing with salicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Fadeeva, V I; Kochetkova, S K [Moskovskij Gosudarstvennyj Univ. (USSR)

    1979-08-01

    A study has been made of the extraction of complexes containing scandium and zirconium compounds and salicylic acid by using benzene, nitrobenzene, chloroform and isoamyl alcohol. It is shown that in the metal concentration range 10/sup -5/-10/sup -3/ mole/l scandium forms mononuclear complexes composed of Sc(HSal)/sub 3/ (pH<=4) and Sc(OH)(HSal)/sub 2/ (pH>4), zirconium - polynuclear complexes Zrsub(x)(OH)sub(y)(HSal)sub(n), where the x:n ratio varies from 0.5 to 1.5. Stability constants have been calculated for the salicylate scandium complexes in aqueous solution, equal to ..beta../sub 1/=(3+-1)x10/sup 2/; ..beta../sub 2/=(5.0+-0.6)x10/sup 4/; ..beta../sub 3/=(5.3+-0.3)x10/sup 6/.

  4. Atomic Gravitational Wave Interferometric Sensors (AGIS) in Space

    Science.gov (United States)

    Sugarbaker, Alex; Hogan, Jason; Johnson, David; Dickerson, Susannah; Kovachy, Tim; Chiow, Sheng-Wey; Kasevich, Mark

    2012-06-01

    Atom interferometers have the potential to make sensitive gravitational wave detectors, which would reinforce our fundamental understanding of gravity and provide a new means of observing the universe. We focus here on the AGIS-LEO proposal [1]. Gravitational waves can be observed by comparing a pair of atom interferometers separated over an extended baseline. The mission would offer a strain sensitivity that would provide access to a rich scientific region with substantial discovery potential. This band is not currently addressed with the LIGO or LISA instruments. We analyze systematic backgrounds that are relevant to the mission and discuss how they can be mitigated at the required levels. Some of these effects do not appear to have been considered previously in the context of atom interferometry, and we therefore expect that our analysis will be broadly relevant to atom interferometric precision measurements. Many of the techniques relevant to an AGIS mission can be investigated in the Stanford 10-m drop tower.[4pt] [1] J.M. Hogan, et al., Gen. Rel. Grav. 43, 1953-2009 (2011).

  5. Hydrogen atom in the phase-space formulation of quantum mechanics

    International Nuclear Information System (INIS)

    Gracia-Bondia, J.M.

    1984-01-01

    Using a coordinate transformation which regularizes the classical Kepler problem, we show that the hydrogen-atom case may be analytically solved via the phase-space formulation of nonrelativistic quantum mechanics. The problem is essentially reduced to that of a four-dimensional oscillator whose treatment in the phase-space formulation is developed. Furthermore, the method allows us to calculate the Green's function for the H atom in a surprisingly simple way

  6. Nuclear Reactors for Space Power, Understanding the Atom Series.

    Science.gov (United States)

    Corliss, William R.

    The historical development of rocketry and nuclear technology includes a specific description of Systems for Nuclear Auxiliary Power (SNAP) programs. Solar cells and fuel cells are considered as alternative power supplies for space use. Construction and operation of space power plants must include considerations of the transfer of heat energy to…

  7. Mesonic atoms. Technical progress report

    International Nuclear Information System (INIS)

    Kunselman, R.

    1981-01-01

    Research on mesic atoms during 1981 is reported. This includes measurement of x-rays from pionic hydrogen and pionic deuterium; muonic K, L, and M x-ray spectra of mercury 199 and mercury 201; and pionic chromium 54, scandium 45, vanadium 51, manganese 55, and iron

  8. Hydrogen atom in momentum space with a minimal length

    International Nuclear Information System (INIS)

    Bouaziz, Djamil; Ferkous, Nourredine

    2010-01-01

    A momentum representation treatment of the hydrogen atom problem with a generalized uncertainty relation, which leads to a minimal length ΔX imin =(ℎ/2π)√(3β+β ' ), is presented. We show that the distance squared operator can be factorized in the case β ' =2β. We analytically solve the s-wave bound-state equation. The leading correction to the energy spectrum caused by the minimal length depends on √(β). An upper bound for the minimal length is found to be about 10 -9 fm.

  9. Scandium/carbon filters for soft x rays

    NARCIS (Netherlands)

    Artioukov, IA; Kasyanov, YS; Kopylets, IA; Pershin, YP; Romanova, SA

    2003-01-01

    This Note deals with thin-film soft x-ray filters for operation at the wavelengths near carbon K edge (similar to4.5 nm). The filters were fabricated by magnetron sputtering deposition of thin layers of scandium (total thickness 0.1-0.2 mum) onto films of polypropylene (thickness 1.5 mum) and

  10. Heat capacity and solid solubility of iron in scandium

    International Nuclear Information System (INIS)

    Tsang, T.-W.E.

    1981-01-01

    The maximum solid solubility of iron in scandium was determined to be between 50 and 85 at.ppm in the as-cast condition. As the concentration of iron increases, it segregates along the grain boundary, as is evident from optical metallography and electron microprobe examinations. Annealing also causes the iron dissolved in scandium to separate out and cluster along the grain boundary. Heat capacity measurements show an anomaly in the C/T versus T 2 plots for iron concentrations of 19 at.ppm or greater. For iron dissolved in solid scandium the excess entropy due to the iron impurity is in agreement with the theoretical prediction of ck ln(2S + 1) for an impurity-conduction electron (Kondo) interaction, but is 4 - 8 times larger than the theoretical prediction when iron segregates along the grain boundary. Furthermore, our results suggest that most of the previously reported low temperature physical properties of scandium are probably in error because of either iron impurity-conduction electron interactions or Fe-Fe interactions in the precipitated second-phase Sc-Fe compound. (Auth.)

  11. Thermoelectric material comprising scandium doped zinc cadmium oxide

    DEFF Research Database (Denmark)

    2016-01-01

    There is presented a composition of scandium doped Zinc Cadmium Oxide with the general formula ZnzCdxScyO which the inventors have prepared, and for which material the inventors have made the insight that it is particularly advantageous as an n-type oxide material, such as particularly advantageous...

  12. Synthesis and properties of scandium ortho-phosphate

    International Nuclear Information System (INIS)

    Eshchenko, L.S.; Pechkovskij, V.V.; Dvoskina, R.N.

    1979-01-01

    With the aim to elucidate the influence of synthesis conditions on the chemical composition and properties of orthophosphates of scandium, the interaction of orthophosphoric acid and scandium-containing component (oxide or salt) was studied under various conditions. In the interaction of scandium salt, phosphoric acid and ammonia at room temperature and pH 3.0; 5.0; 7.0 and 9.0 amorphous scandium phosphates have been obtained with the composition of x Sc 2 O 3 xY P 2 O 5 xz NH 3 xn H 2 O. After prolonged staying in mother liquor, roentgenoamorphous precipitates of phosphates transform into the crystalline state. The dependences are studied of the specific surface of amorphous phosphates on pH of precipitation and temperature of the heat treatment (200-800 deg C). Precipitates obtained in a neutral medium at 400 deg C temperature of thermal treatment, show a maximum specific surface. At a temperature of 820-840 deg C the crystallization of amorphous phase occurs followed by the recrystallization and formation of anhydrous SePO 4 of zircon type

  13. Atom Interferometer Technologies in Space for Gravity Mapping and Gravity Science

    Science.gov (United States)

    Williams, Jason; Chiow, Sheng-Wey; Kellogg, James; Kohel, James; Yu, Nan

    2015-05-01

    Atom interferometers utilize the wave-nature of atomic gases for precision measurements of inertial forces, with potential applications ranging from gravity mapping for planetary science to unprecedented tests of fundamental physics with quantum gases. The high stability and sensitivity intrinsic to these devices already place them among the best terrestrial sensors available for measurements of gravitational accelerations, rotations, and gravity gradients, with the promise of several orders of magnitude improvement in their detection sensitivity in microgravity. Consequently, multiple precision atom-interferometer-based projects are under development at the Jet Propulsion Laboratory, including a dual-atomic-species interferometer that is to be integrated into the Cold Atom Laboratory onboard the International Space Station and a highly stable gravity gradiometer in a transportable design relevant for earth science measurements. We will present JPL's activities in the use of precision atom interferometry for gravity mapping and gravitational wave detection in space. Our recent progresses bringing the transportable JPL atom interferometer instrument to be competitive with the state of the art and simulations of the expected capabilities of a proposed flight project will also be discussed. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  14. Ground-Laboratory to In-Space Atomic Oxygen Correlation for the PEACE Polymers

    Science.gov (United States)

    Stambler, Arielle H.; Inoshita, Karen E.; Roberts, Lily M.; Barbagallo, Claire E.; de Groh, Kim K.; Banks, Bruce A.

    2009-01-01

    The Materials International Space Station Experiment 2 (MISSE 2) Polymer Erosion and Contamination Experiment (PEACE) polymers were exposed to the environment of low Earth orbit (LEO) for 3.95 years from 2001 to 2005. There were forty-one different PEACE polymers, which were flown on the exterior of the International Space Station (ISS) in order to determine their atomic oxygen erosion yields. In LEO, atomic oxygen is an environmental durability threat, particularly for long duration mission exposures. Although space flight experiments, such as the MISSE 2 PEACE experiment, are ideal for determining LEO environmental durability of spacecraft materials, ground-laboratory testing is often relied upon for durability evaluation and prediction. Unfortunately, significant differences exist between LEO atomic oxygen exposure and atomic oxygen exposure in ground-laboratory facilities. These differences include variations in species, energies, thermal exposures and radiation exposures, all of which may result in different reactions and erosion rates. In an effort to improve the accuracy of ground-based durability testing, ground-laboratory to in-space atomic oxygen correlation experiments have been conducted. In these tests, the atomic oxygen erosion yields of the PEACE polymers were determined relative to Kapton H using a radio-frequency (RF) plasma asher (operated on air). The asher erosion yields were compared to the MISSE 2 PEACE erosion yields to determine the correlation between erosion rates in the two environments. This paper provides a summary of the MISSE 2 PEACE experiment; it reviews the specific polymers tested as well as the techniques used to determine erosion yield in the asher, and it provides a correlation between the space and ground-laboratory erosion yield values. Using the PEACE polymers' asher to in-space erosion yield ratios will allow more accurate in-space materials performance predictions to be made based on plasma asher durability evaluation.

  15. Atoms

    International Nuclear Information System (INIS)

    Fuchs, Alain; Villani, Cedric; Guthleben, Denis; Leduc, Michele; Brenner, Anastasios; Pouthas, Joel; Perrin, Jean

    2014-01-01

    Completed by recent contributions on various topics (atoms and the Brownian motion, the career of Jean Perrin, the evolution of atomic physics since Jean Perrin, relationship between scientific atomism and philosophical atomism), this book is a reprint of a book published at the beginning of the twentieth century in which the author addressed the relationship between atomic theory and chemistry (molecules, atoms, the Avogadro hypothesis, molecule structures, solutes, upper limits of molecular quantities), molecular agitation (molecule velocity, molecule rotation or vibration, molecular free range), the Brownian motion and emulsions (history and general features, statistical equilibrium of emulsions), the laws of the Brownian motion (Einstein's theory, experimental control), fluctuations (the theory of Smoluchowski), light and quanta (black body, extension of quantum theory), the electricity atom, the atom genesis and destruction (transmutations, atom counting)

  16. Versatile element for free-space dividing and redirecting neutral-atom clouds

    International Nuclear Information System (INIS)

    Arakelyan, I. V.; Chattrapiban, N.; Mitra, S.; Hill, W. T. III

    2007-01-01

    We introduce a tunnel lock that can be exploited to divide, delay, and alter the direction of traveling clouds of cold atoms. This versatile free-space element is implemented by crossing two atom tunnels formed by low-intensity, blue-detuned dark-hollow (Bessel mode) laser beams. We show that clouds of cold Rb atoms initially moving within one tunnel can be transferred to the other without heating by gating the intensities of the two tunnels--a tunnel lock--with an efficiency limited by the overlap volume. The element also can be used to divide a single cloud into smaller clouds, each having a distinct momentum

  17. A (201)Hg+ Comagnetometer for (199)Hg+ Trapped Ion Space Atomic Clocks

    Science.gov (United States)

    Burt, Eric A.; Taghavi, Shervin; Tjoelker, Robert L.

    2011-01-01

    A method has been developed for unambiguously measuring the exact magnetic field experienced by trapped mercury ions contained within an atomic clock intended for space applications. In general, atomic clocks are insensitive to external perturbations that would change the frequency at which the clocks operate. On a space platform, these perturbative effects can be much larger than they would be on the ground, especially in dealing with the magnetic field environment. The solution is to use a different isotope of mercury held within the same trap as the clock isotope. The magnetic field can be very accurately measured with a magnetic-field-sensitive atomic transition in the added isotope. Further, this measurement can be made simultaneously with normal clock operation, thereby not degrading clock performance. Instead of using a conventional magnetometer to measure ambient fields, which would necessarily be placed some distance away from the clock atoms, first order field-sensitive atomic transition frequency changes in the atoms themselves determine the variations in the magnetic field. As a result, all ambiguity over the exact field value experienced by the atoms is removed. Atoms used in atomic clocks always have an atomic transition (often referred to as the clock transition) that is sensitive to magnetic fields only in second order, and usually have one or more transitions that are first-order field sensitive. For operating parameters used in the (199)Hg(+) clock, the latter can be five orders of magnitude or more sensitive to field fluctuations than the clock transition, thereby providing an unambiguous probe of the magnetic field strength.

  18. Scandium - problem of ultra-trace-element essentiality

    International Nuclear Information System (INIS)

    Kist, A.A.; Zkuk, L.I.; Danilova, E.A.; Makhmudov, E.A.

    2006-01-01

    Full text: Role of constitutional and essential elements in Life is known quite well. It is also well known that all chemical elements present in the living matter. Nevertheless essentiality of at least 55 chemical elements (more than a half of number of natural elements) is still not accepted. In many cases these elements presumably play important role in the Life. On the other hand their essentiality is still under doubt. One of the 'strange' elements in this connection is scandium. Scandium is an element which is very 'simple' for instrumental neutron activation analysis (INAA). For many years in our laboratory were carried out studies on animals and human tissues and fluids elemental composition using INAA in which data for scandium were obtained as 'redundant' information. Essentiality of scandium was newer proven using accepted criteria of elements. Nevertheless in our studies were found various regularities, statistically significant inter-elemental correlations and correlations between elements in tissues and fluids versus clinic and biochemical data. There are some examples. There were found correlations of scandium hair concentration and blood glucose (r=0.68±0.13), body mass index (r=0.86±0.07), leukocyte with phagocytic activity migration inhibition test (r=0.68±0.18), size of cavity of the left heart auricle (r=-0.65±0.16), final systolic bulk (r=0.80±0.12), stroke output of heart (r=-0.79±0.12), final diastolic bulk (0.88±0.0080) etc. In addition using gel filtration in rat liver cytosol was found peak of scandium in elution curve. Examples and correlations given in the paper say in favor that scandium may play quite important role in biological processes and that the biological role of scandium should be studied more intensive. The most important criterion is an appearance of the organism dysfunction in case of removal of the studied elements from the diet (intake) which in all other sides remains completely valuable and disappearance of all

  19. Complexing of scandium with eriochromecyanine R and cetyltrimethylammonium

    International Nuclear Information System (INIS)

    Tikhonov, V.N.; Samarkina, T.V.

    1978-01-01

    Complexing of scandium with eriochromecyanine R (ECC) in the presence of cetyltrimethylammonium (CTA) is studied. At optimum value of pH 6.2 a three-component complex of blue colour is forming with the Sc:ECC:CTA = 1:3:5 relation of compounds. Lambdasub(max) for the complex varies from 585 to 615 nm, molarabsorption coefficient is equal to (1.48+-0.02)x10 5 . A method of photometric determination of Sc with ECC and CTA is suggested. Even considerable quantities of Mg, Ca, Sr, Zn, Cd, La, Mn, Ni do not affect the Sc determination, whereas Cu, Be, Al, Ga, Fe(3) and Pd(2) affect it to a great degree even in relation of 1:1. Camouflaging substances such as fluorides, citrates, tartrates and EDTA prevent from scandium complexing, that is why they should not be used to increase the determination selectivity

  20. Tetragonal ternary borides: superconductivity, ferromagnetism and the role of scandium

    International Nuclear Information System (INIS)

    Matthias, B.T.; Patel, C.K.N.; Barz, H.; Corenzwit, E.; Vandenberg, J.M.

    1978-01-01

    The authors report and discuss two discoveries made while studying the condensation phenomena of ternary rhodium borides, MRh 4 B 4 . M is generally a trivalent transition metal, usually a rare earth element RE. An exception is scandium which by itself does not form an isomorphous boride, but in combination with many other elements will do just that. A suprising correlation between ferromagnetic and superconducting transition temperatures has been found. (Auth.)

  1. Determination of scandium with salicylaldehyde and 2-aminobenzenearsonic acid

    International Nuclear Information System (INIS)

    Farias, P.A.M.; Hainberger, L.; Andrade, H.A.S.

    1984-01-01

    A new method for the spectrophotometric determination of scandium by means of a coloured complex formed with salicylaldehyde and 2-aminobenzenearsonic acid is described. Lambert-Beer's law is followed in the range of 0.2 - 2.0 μg/ml of the final solution. The maximum amounts of 39 ions that may be present without interfering in the method are listed. (Author) [pt

  2. The characteristics of aluminum-scandium alloys processed by ECAP

    International Nuclear Information System (INIS)

    Venkateswarlu, K.; Rajinikanth, V.; Ray, Ajoy Kumar; Xu Cheng; Langdon, Terence G.

    2010-01-01

    Aluminum-scandium alloys were prepared having different scandium additions of 0.2, 1.0 and 2.0 wt.% and these alloys were processed by equal-channel angular pressing (ECAP) at 473 K. The results show the grain refinement of the aluminum matrix and the morphology of the Al 3 Sc precipitates depends strongly on the scandium concentration. The tensile properties were evaluated after ECAP by pulling to failure at initial strain rates from 1.0 x 10 -3 to 1.0 x 10 -1 s -1 . The Al-1% Sc alloy exhibited the highest tensile strength of ∼250 MPa at a strain rate of 1.0 x 10 -1 s -1 . This alloy also exhibited a superior grain refinement of ∼0.4 μm after ECAP where this is attributed to a smaller initial grain size and an optimum volume fraction of dispersed Al 3 Sc precipitates having both micrometer and nanometer sizes.

  3. Application of Temperature-Controlled Thermal Atomization for Printing Electronics in Space

    Science.gov (United States)

    Wu, Chih-Hao; Thompson, Furman V.

    2017-01-01

    Additive Manufacturing (AM) is a technology that builds three dimensional objects by adding material layer-upon-layer throughout the fabrication process. The Electrical, Electronic and Electromechanical (EEE) parts packaging group at Marshall Space Flight Center (MSFC) is investigating how various AM and 3D printing processes can be adapted to the microgravity environment of space to enable on demand manufacturing of electronics. The current state-of-the art processes for accomplishing the task of printing electronics through non-contact, direct-write means rely heavily on the process of atomization of liquid inks into fine aerosols to be delivered ultimately to a machine's print head and through its nozzle. As a result of cumulative International Space Station (ISS) research into the behaviors of fluids in zero-gravity, our experience leads us to conclude that the direct adaptation of conventional atomization processes will likely fall short and alternative approaches will need to be explored. In this report, we investigate the development of an alternative approach to atomizing electronic materials by way of thermal atomization, to be used in place of conventional aerosol generation and delivery processes for printing electronics in space.

  4. Quantum mechanics on phase space: The hydrogen atom and its Wigner functions

    Science.gov (United States)

    Campos, P.; Martins, M. G. R.; Fernandes, M. C. B.; Vianna, J. D. M.

    2018-03-01

    Symplectic quantum mechanics (SQM) considers a non-commutative algebra of functions on a phase space Γ and an associated Hilbert space HΓ, to construct a unitary representation for the Galilei group. From this unitary representation the Schrödinger equation is rewritten in phase space variables and the Wigner function can be derived without the use of the Liouville-von Neumann equation. In this article the Coulomb potential in three dimensions (3D) is resolved completely by using the phase space Schrödinger equation. The Kustaanheimo-Stiefel(KS) transformation is applied and the Coulomb and harmonic oscillator potentials are connected. In this context we determine the energy levels, the amplitude of probability in phase space and correspondent Wigner quasi-distribution functions of the 3D-hydrogen atom described by Schrödinger equation in phase space.

  5. Atom

    International Nuclear Information System (INIS)

    Auffray, J.P.

    1997-01-01

    The atom through centuries, has been imagined, described, explored, then accelerated, combined...But what happens truly inside the atom? And what are mechanisms who allow its stability? Physicist and historian of sciences, Jean-Paul Auffray explains that these questions are to the heart of the modern physics and it brings them a new lighting. (N.C.)

  6. Development of the Science Data System for the International Space Station Cold Atom Lab

    Science.gov (United States)

    van Harmelen, Chris; Soriano, Melissa A.

    2015-01-01

    Cold Atom Laboratory (CAL) is a facility that will enable scientists to study ultra-cold quantum gases in a microgravity environment on the International Space Station (ISS) beginning in 2016. The primary science data for each experiment consists of two images taken in quick succession. The first image is of the trapped cold atoms and the second image is of the background. The two images are subtracted to obtain optical density. These raw Level 0 atom and background images are processed into the Level 1 optical density data product, and then into the Level 2 data products: atom number, Magneto-Optical Trap (MOT) lifetime, magnetic chip-trap atom lifetime, and condensate fraction. These products can also be used as diagnostics of the instrument health. With experiments being conducted for 8 hours every day, the amount of data being generated poses many technical challenges, such as downlinking and managing the required data volume. A parallel processing design is described, implemented, and benchmarked. In addition to optimizing the data pipeline, accuracy and speed in producing the Level 1 and 2 data products is key. Algorithms for feature recognition are explored, facilitating image cropping and accurate atom number calculations.

  7. Adsorption and desorption of hydrolyzed metal ions. 3. Scandium and chromium

    International Nuclear Information System (INIS)

    Gray, B.; Matijevic, E.; Clarkson Univ., Potsdam, NY

    1987-01-01

    Adsorption of scandium(III) and chromium(III) species on a PVC latex was measured using radioactive isotopes; the uptake increased with increasing pH. The data were interpreted by combining aspects of the models of James and Healy and also of Anderson and Bockris. The experimental and calculated results agree quite well for scandium, but not for chromium. The deviation in the latter case is believed to be due to polymerization of the hydrolyzed chromium cations and to the interaction of chromium with the anionic surface groups of the latex. Neither of these interactions occur with scandium. Hydrolyzed scandium species adsorbed on the latex were removed by acidifying the dispersion, while chromium complexes were not, substantiating the proposed difference in the chemical nature of chromium and scandium species at the solid/solution interface. 32 refs.; 8 figs.; 8 tabs

  8. A new model for prediction of dispersoid precipitation in aluminium alloys containing zirconium and scandium

    International Nuclear Information System (INIS)

    Robson, J.D.

    2004-01-01

    A model has been developed to predict precipitation of ternary Al 3 (Sc, Zr) dispersoids in aluminium alloys containing zirconium and scandium. The model is based on the classical numerical method of Kampmann and Wagner, extended to predict precipitation of a ternary phase. The model has been applied to the precipitation of dispersoids in scandium containing AA7050. The dispersoid precipitation kinetics and number density are predicted to be sensitive to the scandium concentration, whilst the dispersoid radius is not. The dispersoids are predicted to enrich in zirconium during precipitation. Coarsening has been investigated in detail and it has been predicted that a steady-state size distribution is only reached once coarsening is well advanced. The addition of scandium is predicted to eliminate the dispersoid free zones observed in scandium free 7050, greatly increasing recrystallization resistance

  9. Digital atom interferometer with single particle control on a discretized space-time geometry.

    Science.gov (United States)

    Steffen, Andreas; Alberti, Andrea; Alt, Wolfgang; Belmechri, Noomen; Hild, Sebastian; Karski, Michał; Widera, Artur; Meschede, Dieter

    2012-06-19

    Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 x 10(-4) in units of gravitational acceleration g.

  10. Comparing Laser Interferometry and Atom Interferometry Approaches to Space-Based Gravitational-Wave Measurement

    Science.gov (United States)

    Baker, John; Thorpe, Ira

    2012-01-01

    Thoroughly studied classic space-based gravitational-wave missions concepts such as the Laser Interferometer Space Antenna (LISA) are based on laser-interferometry techniques. Ongoing developments in atom-interferometry techniques have spurred recently proposed alternative mission concepts. These different approaches can be understood on a common footing. We present an comparative analysis of how each type of instrument responds to some of the noise sources which may limiting gravitational-wave mission concepts. Sensitivity to laser frequency instability is essentially the same for either approach. Spacecraft acceleration reference stability sensitivities are different, allowing smaller spacecraft separations in the atom interferometry approach, but acceleration noise requirements are nonetheless similar. Each approach has distinct additional measurement noise issues.

  11. Interference of Single Photons Emitted by Entangled Atoms in Free Space

    Science.gov (United States)

    Araneda, G.; Higginbottom, D. B.; Slodička, L.; Colombe, Y.; Blatt, R.

    2018-05-01

    The generation and manipulation of entanglement between isolated particles has precipitated rapid progress in quantum information processing. Entanglement is also known to play an essential role in the optical properties of atomic ensembles, but fundamental effects in the controlled emission and absorption from small, well-defined numbers of entangled emitters in free space have remained unobserved. Here we present the control of the emission rate of a single photon from a pair of distant, entangled atoms into a free-space optical mode. Changing the length of the optical path connecting the atoms modulates the single-photon emission rate in the selected mode with a visibility V =0.27 ±0.03 determined by the degree of entanglement shared between the atoms, corresponding directly to the concurrence Cρ=0.31 ±0.10 of the prepared state. This scheme, together with population measurements, provides a fully optical determination of the amount of entanglement. Furthermore, large sensitivity of the interference phase evolution points to applications of the presented scheme in high-precision gradient sensing.

  12. Relativistic effects on complexity indexes in atoms in position and momentum spaces

    International Nuclear Information System (INIS)

    Maldonado, P.; Sarsa, A.; Buendia, E.; Galvez, F.J.

    2010-01-01

    Three different statistical measures of complexity are explored for the atoms He to Ra. The measures are analysed in both position and momentum spaces. Relativistic effects on the complexity indexes are systematically studied. These effects are discussed in terms of the information content factor and the disorder terms of the complexity indexes. Relativistic and non-relativistic complexity indexes are calculated from Optimized Effective Potential densities.

  13. Kinetics and mechanism of hydrolysis of scandium sulfate

    International Nuclear Information System (INIS)

    Koshchej, E.V.; Stryapkov, A.V.; Podosenov, D.E.; Makarov, G.V.; Razdobreev, D.A.

    1998-01-01

    The Sc 2 (SO 4 ) 3 -H 2 SO 4 -H 2 O system is studied through the methods of pH-potentiometry, conductometry and turbidimetry at 298 and 318 K and ion force 0.01, 0.1 and 1.0. The hydrolysis mechanism including the processes in the system homogenous and heterogeneous constituents. The hydrolysis rates of scandium salts and their dependences on OH-ions concentration, solution ions force and temperature are found; the constants of the processes rate with participation of OH - and SO 4 2- ions and constants of the solid phase formation rate are calculated [ru

  14. Vibrational spectra of double oxides of calcium and scandium

    International Nuclear Information System (INIS)

    Porotnikov, N.V.; Kondratov, O.I.; Petrov, K.I.; Olikov, I.I.

    1981-01-01

    The vibrational spectra of calcium and scandium double oxides 40 CaSc 2 O 4 and 44 CaSc 2 O 4 in the range of 30-1000 cm -1 are studied. In the approximation of the polymer chains of the method of valent-force field the calculation of the theoretical vibrational spectrum of isotope-substituted compounds is made, the attribution of the experimental spectra is suggested, the frequency branches of the vibrations of periodic chains are built, the force field of crystals is evaluated [ru

  15. Study on the coextraction of scandium-yttrium-lumogallion complex

    International Nuclear Information System (INIS)

    Okada, T.; Shimoishi, Y.; Miyata, H.; Toei, K.

    1977-01-01

    The coextraction of scandium-yttrium-lumogallion [LMG;4-chloro-6-(2,4-dihydroxyphenylazo)-1-hydroxybenzene-2-sulfonic acid] into diethyl ether has been studied. The acid dissociation constants of LMG, pKsub(a2) and pKsub(a3), were estimated to be 6.24 and 8.05 respectively. The composition of the complex extracted was determined by using the radioisotopes 46 Sc and 90 Y and by spectrophotometry of LMG and the ratio of the components was Sc:Y:LMG = 1:1:3. The coextraction scheme was discussed briefly. (author)

  16. Cold Atom Interferometers Used In Space (CAIUS) for Measuring the Earth's Gravity Field

    Science.gov (United States)

    Carraz, O.; Luca, M.; Siemes, C.; Haagmans, R.; Silvestrin, P.

    2016-12-01

    In the past decades, it has been shown that atomic quantum sensors are a newly emerging technology that can be used for measuring the Earth's gravity field. There are two ways of making use of that technology: One is a gravity gradiometer concept and the other is in a low-low satellite-to-satellite ranging concept. Whereas classical accelerometers typically suffer from high noise at low frequencies, Cold Atom Interferometers are highly accurate over the entire frequency range. We recently proposed a concept using cold atom interferometers for measuring all diagonal elements of the gravity gradient tensor and the full spacecraft angular velocity in order to achieve better performance than the GOCE gradiometer over a larger part of the spectrum, with the ultimate goals of determining the fine structures in the gravity field better than today. This concept relies on a high common mode rejection, which relaxes the drag free control compare to GOCE mission, and benefits from a long interaction time with the free falling clouds of atoms due to the micro gravity environment in space as opposed to the 1-g environment on-ground. Other concept is also being studied in the frame of NGGM, which relies on the hybridization between quantum and classical techniques to improve the performance of accelerometers. This could be achieved as it is realized in frequency measurements where quartz oscillators are phase locked on atomic or optical clocks. This technique could correct the spectrally colored noise of the electrostatic accelerometers in the lower frequencies. In both cases, estimation of the Earth gravity field model from the instruments has to be evaluated taking into account different system parameters such as attitude control, altitude of the satellite, time duration of the mission, etc. Miniaturization, lower consumptions and upgrading Technical Readiness Level are the key engineering challenges that have to be faced for these space quantum technologie.

  17. Detection of cold gas releases in space via low energy neutral atom imaging

    International Nuclear Information System (INIS)

    McComas, D.J.; Funsten, H.O.; Moore, K.R.; Scime, E.E.; Thomsen, M.F.

    1993-01-01

    Low energy neutral atoms (LENAs) are produced in space plasmas by charge exchange between the ambient magnetospheric plasma ions and cold neutral atoms. Under normal conditions these cold neutrals come from the terrestrial geocorona, a shroud of few-eV hydrogen atoms surrounding the Earth. As a consequence of this charge exchange, it has become possible to remotely image many regions of the magnetosphere for the first time utilizing recently developed LENA imaging technology. In addition to the natural hydrogen geocorona, conventional explosions and maneuvering thruster firings can also introduce large amounts of cold gas into the space environment. In this paper the authors examine whether such potentially clandestine activities could also be remotely observed for the first time via LENA imaging. First, they examine the fluxes of LENAs produced in the space environment from a conventional explosion. Then they review the present state of the art in the emerging field of LENA detection and imaging. Recent work has shown that LENAs can be imaged by first converting the neutrals to ions with ultra-thin (10s of angstrom) foils and then electrostatically analyzing these newly created ions to reject the large (> 10 10 cm -2 s -1 ) UV background to which the low energy detectors are sensitive. They conclude that the sensitivities for present LENA imager designs may be just adequate for detecting some man-made releases. With additional improvements in LENA detection capabilities, this technique could become an important new method for monitoring for conventional explosions, as well as other man-made neutral releases, in the space environment

  18. Three-dimensional theory for interaction between atomic ensembles and free-space light

    International Nuclear Information System (INIS)

    Duan, L.-M.; Cirac, J.I.; Zoller, P.

    2002-01-01

    Atomic ensembles have shown to be a promising candidate for implementations of quantum information processing by many recently discovered schemes. All these schemes are based on the interaction between optical beams and atomic ensembles. For description of these interactions, one assumed either a cavity-QED model or a one-dimensional light propagation model, which is still inadequate for a full prediction and understanding of most of the current experimental efforts that are actually taken in the three-dimensional free space. Here, we propose a perturbative theory to describe the three-dimensional effects in interaction between atomic ensembles and free-space light with a level configuration important for several applications. The calculations reveal some significant effects that were not known before from the other approaches, such as the inherent mode-mismatching noise and the optimal mode-matching conditions. The three-dimensional theory confirms the collective enhancement of the signal-to-noise ratio which is believed to be one of the main advantages of the ensemble-based quantum information processing schemes, however, it also shows that this enhancement needs to be understood in a more subtle way with an appropriate mode-matching method

  19. An atomic model of brome mosaic virus using direct electron detection and real-space optimization

    Science.gov (United States)

    Wang, Zhao; Hryc, Corey F.; Bammes, Benjamin; Afonine, Pavel V.; Jakana, Joanita; Chen, Dong-Hua; Liu, Xiangan; Baker, Matthew L.; Kao, Cheng; Ludtke, Steven J.; Schmid, Michael F.; Adams, Paul D.; Chiu, Wah

    2014-09-01

    Advances in electron cryo-microscopy have enabled structure determination of macromolecules at near-atomic resolution. However, structure determination, even using de novo methods, remains susceptible to model bias and overfitting. Here we describe a complete workflow for data acquisition, image processing, all-atom modelling and validation of brome mosaic virus, an RNA virus. Data were collected with a direct electron detector in integrating mode and an exposure beyond the traditional radiation damage limit. The final density map has a resolution of 3.8 Å as assessed by two independent data sets and maps. We used the map to derive an all-atom model with a newly implemented real-space optimization protocol. The validity of the model was verified by its match with the density map and a previous model from X-ray crystallography, as well as the internal consistency of models from independent maps. This study demonstrates a practical approach to obtain a rigorously validated atomic resolution electron cryo-microscopy structure.

  20. Scandium effect on mechanical properties of Al-6.5 % Mg alloy

    International Nuclear Information System (INIS)

    Drits, M.E.; Toropova, L.S.; Bykov, Yu.G.

    1982-01-01

    Quantitative evaluation of influence of small scandium additions (up to 0.5 wt%) on properties of Al-6.5% Mg binary alloy are carried out depending on test temperature in the range of -196 to 310 deg C. Alloys were tested on ''Instron'' machine at 1.3x10 - 3 s - 1 strain rate. Scandium additions are shown to increase plasticity at -196 deg C. Yield strength also increases with introduction of 0.2% Sc if deformation temperature does not exceed 250 deg C. The growth of ultimate strength is less significant. Elevated strength properties of alloys with scandium additions can be explained by a fine-grained structure

  1. Effect of scandium additions on microstructure and mechanical properties of Al-Zn-Mg alloy welds

    International Nuclear Information System (INIS)

    Dev, Selvi; Stuart, A. Archibald; Kumaar, R.C. Ravi Dev; Murty, B.S.; Rao, K. Prasad

    2007-01-01

    The microstructure and mechanical properties of fusion zones of medium strength Al-Zn-Mg alloy (RDE-40) welds obtained by using different fillers containing various amount of scandium was investigated. It was observed that addition of scandium led to very significant grain refinement in the fusion zone especially for scandium levels greater than the eutectic composition (0.55 wt%). The grain refinement led to the reduction in solidification cracking and improved the tensile properties of fusion zone compared to the ones obtained by the commercial AA5556 filler

  2. A Technology Demonstration Experiment for Laser Cooled Atomic Clocks in Space

    Science.gov (United States)

    Klipstein, W. M.; Kohel, J.; Seidel, D. J.; Thompson, R. J.; Maleki, L.; Gibble, K.

    2000-01-01

    We have been developing a laser-cooling apparatus for flight on the International Space Station (ISS), with the intention of demonstrating linewidths on the cesium clock transition narrower than can be realized on the ground. GLACE (the Glovebox Laser- cooled Atomic Clock Experiment) is scheduled for launch on Utilization Flight 3 (UF3) in 2002, and will be mounted in one of the ISS Glovebox platforms for an anticipated 2-3 week run. Separate flight definition projects funded at NIST and Yale by the Micro- gravity Research Division of NASA as a part of its Laser Cooling and Atomic Physics (LCAP) program will follow GLACE. Core technologies for these and other LCAP missions are being developed at JPL, with the current emphasis on developing components such as the laser and optics subsystem, and non-magnetic vacuum-compatible mechanical shutters. Significant technical challenges in developing a space qualifiable laser cooling apparatus include reducing the volume, mass, and power requirements, while increasing the ruggedness and reliability in order to both withstand typical launch conditions and achieve several months of unattended operation. This work was performed at the Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration.

  3. Temperature and phase-space density of a cold atom cloud in a quadrupole magnetic trap

    Energy Technology Data Exchange (ETDEWEB)

    Ram, S. P.; Mishra, S. R.; Tiwari, S. K.; Rawat, H. S. [Raja Ramanna Centre for Advanced Technology, Indore (India)

    2014-08-15

    We present studies on modifications in the temperature, number density and phase-space density when a laser-cooled atom cloud from optical molasses is trapped in a quadrupole magnetic trap. Theoretically, for a given temperature and size of the cloud from the molasses, the phase-space density in the magnetic trap is shown first to increase with increasing magnetic field gradient and then to decrease with it after attaining a maximum value at an optimum value of the magnetic-field gradient. The experimentally-measured variation in the phase-space density in the magnetic trap with changing magnetic field gradient is shown to exhibit a similar trend. However, the experimentally-measured values of the number density and the phase-space density are much lower than the theoretically-predicted values. This is attributed to the experimentally-observed temperature in the magnetic trap being higher than the theoretically-predicted temperature. Nevertheless, these studies can be useful for setting a higher phase-space density in the trap by establishing an optimal value of the field gradient for a quadrupole magnetic trap.

  4. Complexonometric photometric titration of scandium in the presence of xylenol orange

    International Nuclear Information System (INIS)

    Kornev, V.I.

    1977-01-01

    Possibility has been studied of using xylenol orange (XO) for chelatometric determination of scandium by means of various chelates with the aid of photometric techniques. It has been established that the chelates applicable for the purpose are ethylenediamineteraacetic acid (EDTA), diethylenediaminetetraacetic acid (DEDTA), diethylenetriaminepentaacetic acid (DETPA), upon introducing of which into a solution containing a complex of scandium with XO (maximum light adsorption at 550 nm) the optical density gradually diminishes. Weakening of the light absorption is, evidently, associated with the destruction of the scandium complex with XO and formation of a colourless chelate acetate with one of the chelates. Chelatometric determination of scandium, using EDTA, DEDTA and DEPTA solutions with XO should be carried out in an acidic medium at pH=2.5-3.0. In this range of pH values interferences caused by the appearance of the Sc-XO complex in the solution are insignificant

  5. Knight shift in scandium and its alloys with hafnium and titanium

    International Nuclear Information System (INIS)

    Chachkhiani, Z.B.; Chechernikov, V.I.; Martynova, L.F.; Nidel'ko, V.I.; Chachkhiani, L.G.; Georgadze, G.S.

    1981-01-01

    Results of the investigation of NMR on 45 Sc nuclei and magnetic susceptibility of scandium and its solid solutions with titanium and hafnium are presented. It is shown that the existing hybridization of S and d zones in pure scandium and its alloys with titanium and hafnium affects the Knight shift reducing the value of the contact contribution. The temperature behaviour of the Knight shift from the temperature dependence and spin susceptibility of collectivized d electrons [ru

  6. Use of scandium ionic associates with salicylic- or 2-phenylquinoline-4-carboxylic acid and rhodamine C

    Energy Technology Data Exchange (ETDEWEB)

    Kononenko, L.I.; Bel' tyukova, S V; Drobyazko, V N; Poluehktov, N S [AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; AN Ukrainskoj SSR, Odessa. Inst. Obshchej i Neorganicheskoj Khimii)

    1975-09-01

    With salicylic or 2-phenylquinoline-4-carboxylic acid and rhodamine C scandium forms ion associations whose benzene solutions are capable of luminescence. Optimum conditions for the formation of complexes and the composition of the complex with the ratio of Sc:acid:rhodamine C = 1:2:1 are established. A possibility of luminescence determination of scandium in the presence of rare earths is shown.

  7. Analogs of N-cynnamoylphenylhydroxylamine as reagents for amperometric determination of scandium

    International Nuclear Information System (INIS)

    Shvedene, N.V.; Gallaj, Z.A.; Sheina, N.M.; Zujkova, N.V.

    1978-01-01

    To decrease the detection limit of scandium and increase selectivity of amperometric determination, oxidation of 2-furylacryloyl-N-p-chlorophenylhydroxylamine (FACPhHA) and 3-styrylacryloyl-N-phenylhydroxylamine (SAPhHA) on a graphite electrode has been studied by volt-amperometry. The possibility has been established of using the oxidation current of the reagent for plotting the titration curves. The solubility of scandium complexes with FACPhHA and SAPhHA under conditions of titration against the background with pH 6.0 has been determined and equals (2.1+-0.3)x10 -6 and (5.3+-0.3)x10 -7 , respectively. The methods have been developed of amperometric determination of scandium with the use of the considered reagents against backgrounds with pH 5.5-6.5. The use of SAPhHA has decreased the limit of scandium detection down to 0.1 mgk/ml. Besides, the amperometric method makes it possible to titrate in turbid and coloured media what is an advantage of this method. The developed method is used for determination of scandium in scandium silicide

  8. Effect of composition on the superplasticity of aluminium scandium alloys

    International Nuclear Information System (INIS)

    Bradley, E.L. III; Morris, J.W. Jr.

    1992-01-01

    Several aluminum alloys have been shown to exhibit superplasticty in the as-rolled condition. Previous work has shown that aluminum-scandium alloys also exhibit this behavior, but only with the addition of ternary alloying elements such as lithium and magnesium. These additions raised the strain-rate sensitivity of these alloys to 0.4-0.5 for selected strain rates at temperatures above 400 degrees C. A systematic study was undertaken of five Al-Sc alloys with varying lithium and magnesium concentrations in order to fully characterize the high temperature deformation mechanism. Specimens were deformed at a constant strain rate to predetermined true strains for textural and microstructural characterization. In this paper work is presented that will elucidate the effect of these different ternary additives on the superplastic deformation mechanism in these alloys

  9. Application of scandium oxide in an electron emission material

    International Nuclear Information System (INIS)

    Suqiu, Y.; Zhizheng, Z.; Yongde, W.

    1985-01-01

    Modern microwave devices impose a number of harsh requirements on the cathodes. For instance, they require cathodes having low working temperature, high emissive current density, slow evaporation rate of the emissive-active material, long lifetime, quick heating and so on. The commercial B-cathode is no longer able to meet these requirements completely. A scandate cathode may be a promising one for use in these devices. Adding rare-earth elements in the electron emission material has been reported in many papers. Based on a B-cathode we add a little amount of scandium oxide (about 3%) into emission material to manufacture a scandate cathode. The emission property of such a cathode has been improved greatly. If the composition is controlled correctly, the emission level of such a cathode may be five times more as high as the B-cathode

  10. Order-disorder phenomenon in lead scandium tantalate

    International Nuclear Information System (INIS)

    Wang, H.C.; Schulze, W.A.

    1990-01-01

    Lead scandium tatalate (PST) is a ferroelectric relaxor with the perovskite structure of A(B'B double-prime)O 3 . By suitable heat treatment, the B-site cations can be brought from a structurally disordered state into various degree of ordering. The degree of ordering is strongly affected by the amount of vacancies present in the materials. To suppress PbO loss during the sintering or annealing process, a PbO-rich atmosphere is supplied by materials having high PbO vapor pressure, such as PbZrO 3 . For PST ceramics with nearly zero weight loss, very long annealing times and higher annealing temperatures are required for ordering. The higher PbO-loss materials are found to be easily ordered. The introduction of a reducing atmosphere during annealing enhances the ordering process. The ordering process is characterized quantitatively by X-ray diffraction and qualitatively by Raman spectroscopy

  11. Effects of Atomic Oxygen and Grease on Outgassing and Adhesion of Silicone Elastomers for Space Applications

    Science.gov (United States)

    de Groh, Henry C.; Puleo, Bernadette J.; Steinetz, Bruce M.

    An investigation of silicone elastomers for seals used in docking and habitat systems for future space exploration vehicles is being conducted at NASA. For certain missions, NASA is considering androgynous docking systems where two vehicles each having a seal would be required to: dock for a period of time, seal effectively, and then separate with minimum push-off forces for undocking. Silicone materials are generally chosen for their wide operating temperatures and low leakage rates. However silicone materials are often sticky and usually exhibit considerable adhesion when mated against metals and silicone surfaces. This paper investigates the adhesion unit pressure for a space rated silicone material (S0383-70) for either seal-on-seal (SoS) or seal-on-aluminum (SoAl) operation modes in the following conditions: as-received, after ground-based atomic-oxygen (AO) pre-treatment, after application of a thin coating of a space-qualified grease (Braycote 601EF), and after a combination of AO pre-treatment and grease coating. In order of descending adhesion reduction, the AO treatment reduced seal adhesion the most, followed by the AO plus grease pre-treatment, followed by the grease treatment. The effects of various treatments on silicone (S0383-70 and ELA-SA-401) outgassing properties were also investigated. The leading adhesion AO pre-treatment reduction led to a slight decrease in outgassing for the S0383-70 material and virtually no change in ELA-SA-401 outgassing.

  12. Nano-Particle Scandate Cathode for Space Communications Phase 2, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an improved cathode based on our novel theory of the role of scandium oxide in enhancing emission in tungsten-impregnated cathodes. Recent results have...

  13. Revealing the correlation between real-space structure and chiral magnetic order at the atomic scale

    Science.gov (United States)

    Hauptmann, Nadine; Dupé, Melanie; Hung, Tzu-Chao; Lemmens, Alexander K.; Wegner, Daniel; Dupé, Bertrand; Khajetoorians, Alexander A.

    2018-03-01

    We image simultaneously the geometric, the electronic, and the magnetic structures of a buckled iron bilayer film that exhibits chiral magnetic order. We achieve this by combining spin-polarized scanning tunneling microscopy and magnetic exchange force microscopy (SPEX) to independently characterize the geometric as well as the electronic and magnetic structures of nonflat surfaces. This new SPEX imaging technique reveals the geometric height corrugation of the reconstruction lines resulting from strong strain relaxation in the bilayer, enabling the decomposition of the real-space from the electronic structure at the atomic level and the correlation with the resultant spin-spiral ground state. By additionally utilizing adatom manipulation, we reveal the chiral magnetic ground state of portions of the unit cell that were not previously imaged with spin-polarized scanning tunneling microscopy alone. Using density functional theory, we investigate the structural and electronic properties of the reconstructed bilayer and identify the favorable stoichiometry regime in agreement with our experimental result.

  14. Concentration and Separation of Scandium from Ni Laterite Ore Processing Streams

    Directory of Open Access Journals (Sweden)

    Şerif Kaya

    2017-12-01

    Full Text Available The presence of a considerable amount of scandium in lateritic nickel-cobalt ores necessitates the investigation of possible processing alternatives to recover scandium as a byproduct during nickel and cobalt production. Therefore, in this study, rather than interfering with the main nickel-cobalt production circuit, the precipitation-separation behavior of scandium during a pH-controlled precipitation process from a synthetically prepared solution was investigated to adopt the Sc recovery circuit into an already existing hydrometallurgical nickel-cobalt hydroxide processing plant. The composition of the synthetic solution was determined according to the hydrometallurgical nickel laterite ore processing streams obtained from a HPAL (high-pressure sulphuric acid leaching process. In order to selectively precipitate and concentrate scandium with minimum nickel and cobalt co-precipitation, the pH of the solution was adjusted by CaCO3, MgO, Na2CO3, and NaOH. It was found that precipitation with MgO or Na2CO3 is more advantageous to obtain a precipitate containing higher amounts of scandium with minimum mass when compared to the CaCO3 route, which makes further processing more viable. As a result of this study, it is proposed that by a simple pH-controlled precipitation process, scandium can be separated from the nickel and cobalt containing process solutions as a byproduct without affecting the conventional nickel-cobalt hydroxide production. By further processing this scandium-enriched residue by means of leaching, SX (solvent extraction, and precipitation, an intermediate (NH42NaScF6 product can be obtained.

  15. Analysis of separation quality of scandium-46 and titanium using silica gel column

    International Nuclear Information System (INIS)

    Muhamad Basit Febrian; Yanuar Setiadi; Duyeh Setiawan; Titin Sri Mulyati; Nana Suherman

    2015-01-01

    In this study, quality test of scandium and titanium mixture separation system using a silica gel column has been conducted. This system will be used in the separation of medical radioisotopes of 47 Sc from TiO 2 enriched targets. 20 mg of TiO 2 and 5 mg of Sc 2 O 3 dissolved using 0.5 mL of 50% HF solvent with gentle heating at 60°C - 80°C for 1 hour then 4.5 mL H 2 O was added. Sc and Ti mixture is separated by passing it through a column of silica gel. In the determination of scandium released from silica gel, Sc-46 radiotracer was used. Only 51.60 ± 4.5% of 5 mg of scandium could be retained in the silica gel column. From 51.60% of absorbed scandium in the column, 98.29 ± 3.4% were eluted with 5 mL of H 2 O eluent. During elution of scandium from silica gel column, 2.81 grams of 20 mg of titanium came apart as breakthrough. In determination of recovery of titanium from silica gel, 51.76 ± 5.5% of the 20 mg Ti can be recovered from silica gel column using 5M HCl eluent, whereas remaining Ti were eluted using 40 ml of HCl 5M. Based on those result, it can be concluded that there are still titanium portion in scandium after the separation using a silica gel column. Further purification step using fresh silica gel column, can separate escaped titanium from scandium. (author)

  16. On interaction of zirconium isopropylate with scandium and lanthanum isopropylates. Alkoxozirconates of the scandium subgroup

    International Nuclear Information System (INIS)

    Turova, N.Ya.; Kozlova, N.I.

    1982-01-01

    The solubility in the Zr(OR) 4 -Sc(OR) 3 -THF and Zr(OR) 4 -La(OR) 3 -ROH (R=iso-Pr) at 20 deg was studied. It was ascertained that complex formation did not occur in the first system and LaZr 3 (OR) 15 x3ROH were present in the second one. Complex properties were studied by the methods of IR, PMR spectroscopy, mass-spectrometric and preparative methods. A structure with octahedric coordination of M 3 and Zr atoms was supposed for M 3 Zr 3 (OR) 15 x3L (M=Y, La). Regularities in the change of Sc, Y, La alkoxozirconates were established

  17. Ground-Laboratory to In-Space Atomic Oxygen Correlation for the Polymer Erosion and Contamination Experiment (PEACE) Polymers

    Science.gov (United States)

    Stambler, Arielle H.; Inoshita, Karen E.; Roberts, Lily M.; Barbagallo, Claire E.; deGroh, Kim K.; Banks, Bruce A.

    2011-01-01

    The Materials International Space Station Experiment 2 (MISSE 2) Polymer Erosion and Contamination Experiment (PEACE) polymers were exposed to the environment of low Earth orbit (LEO) for 3.95 years from 2001 to 2005. There were 41 different PEACE polymers, which were flown on the exterior of the International Space Station (ISS) in order to determine their atomic oxygen erosion yields. In LEO, atomic oxygen is an environmental durability threat, particularly for long duration mission exposures. Although spaceflight experiments, such as the MISSE 2 PEACE experiment, are ideal for determining LEO environmental durability of spacecraft materials, ground-laboratory testing is often relied upon for durability evaluation and prediction. Unfortunately, significant differences exist between LEO atomic oxygen exposure and atomic oxygen exposure in ground-laboratory facilities. These differences include variations in species, energies, thermal exposures and radiation exposures, all of which may result in different reactions and erosion rates. In an effort to improve the accuracy of ground-based durability testing, ground-laboratory to in-space atomic oxygen correlation experiments have been conducted. In these tests, the atomic oxygen erosion yields of the PEACE polymers were determined relative to Kapton H using a radio-frequency (RF) plasma asher (operated on air). The asher erosion yields were compared to the MISSE 2 PEACE erosion yields to determine the correlation between erosion rates in the two environments. This paper provides a summary of the MISSE 2 PEACE experiment; it reviews the specific polymers tested as well as the techniques used to determine erosion yield in the asher, and it provides a correlation between the space and ground laboratory erosion yield values. Using the PEACE polymers asher to in-space erosion yield ratios will allow more accurate in-space materials performance predictions to be made based on plasma asher durability evaluation.

  18. Carbon fiber CVD coating by carbon nanostructured for space materials protection against atomic oxygen

    Science.gov (United States)

    Pastore, Roberto; Bueno Morles, Ramon; Micheli, Davide

    2016-07-01

    In recent years, the emphasis in space research has been shifting from space exploration to commercialization of space. In order to utilize space for commercial purposes it is necessary to understand the low earth orbit (LEO) space environment where most of the activities will be carried out. The studies on the LEO environment are mainly focused towards understanding the effect of atomic oxygen (AO) on spacecraft materials. In the first few shuttle flights, materials looked frosty because they were actually being eroded and textured: AO reacts with organic materials on spacecraft exteriors, gradually damaging them. When a spacecraft travel in LEO (where crewed vehicles and the International Space Station fly), the AO formed from the residual atmosphere can react with the spacecraft surfaces, causing damage to the vehicle. Polymers are widely used in space vehicles and systems as structural materials, thermal blankets, thermal control coatings, conformal coatings, adhesives, lubricants, etc. Exposure of polymers and composites to the space environment may result in different detrimental effects via modification of their chemical, electrical, thermal, optical and mechanical properties as well as surface erosion. The major degradation effects in polymers are due to their exposure to atomic oxygen, vacuum ultraviolet and synergistic effects, which result in different damaging effects by modification of the polymer's chemical properties. In hydrocarbon containing polymers the main AO effect is the surface erosion via chemical reactions and the release of volatile reaction products associated with the mass loss. The application of a thin protective coating to the base materials is one of the most commonly used methods of preventing AO degradation. The purpose is to provide a barrier between base material and AO environment or, in some cases, to alter AO reactions to inhibit its diffusion. The effectiveness of a coating depends on its continuity, porosity, degree of

  19. Effects of iron on intermetallic compound formation in scandium modified Al–Si–Mg Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [National Metal and Materials Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@mail.kmutt.ac.th [Production Engineering Department, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2014-12-15

    Highlights: • Iron reduces the modification effects of scandium in Al–Si–Mg alloys. • Morphologies of Sc-rich intermetallic phases vary with Fe and Sc contents and the cooling rates. • Sc neutralizes effects of Fe by changing Fe-rich intermetallic phases from platelets to more cubic. - Abstract: In general, iron has a strong tendency to dissolve in molten aluminum. Iron has very low solid solubility in aluminum–silicon casting alloys, so it will form intermetallic compounds that cause detrimental effects on mechanical properties. In this work, the effects of iron on intermetallic compound formations in scandium modified Al–Si–Mg alloys were studied. There were two levels of iron addition (0.2 and 0.4 wt.%) and two levels of scandium addition (0.2 and 0.4 wt.%). We found that the effects of scandium modification decreased with increasing iron addition. The morphologies of the complex intermetallic compounds were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. It was found that scandium changes the morphology of Fe-rich intermetallic compounds from β-phase (plate-like) to α-phase, which reduces the harmful effects of β-phase.

  20. Testing general relativity and alternative theories of gravity with space-based atomic clocks and atom interferometers

    Directory of Open Access Journals (Sweden)

    Bondarescu Ruxandra

    2015-01-01

    Full Text Available The successful miniaturisation of extremely accurate atomic clocks and atom interferometers invites prospects for satellite missions to perform precision experiments. We discuss the effects predicted by general relativity and alternative theories of gravity that can be detected by a clock, which orbits the Earth. Our experiment relies on the precise tracking of the spacecraft using its observed tick-rate. The spacecraft’s reconstructed four-dimensional trajectory will reveal the nature of gravitational perturbations in Earth’s gravitational field, potentially differentiating between different theories of gravity. This mission can measure multiple relativistic effects all during the course of a single experiment, and constrain the Parametrized Post-Newtonian Parameters around the Earth. A satellite carrying a clock of fractional timing inaccuracy of Δ f / f ∼ 10−16 in an elliptic orbit around the Earth would constrain the PPN parameters |β − 1|, |γ − 1| ≲ 10−6. We also briefly review potential constraints by atom interferometers on scalar tensor theories and in particular on Chameleon and dilaton models.

  1. Double tungstates of metals of scandium and ammonium subgroups

    Energy Technology Data Exchange (ETDEWEB)

    Maksin, V I [AN Ukrainskoj SSR, Kiev. Inst. Kolloidnoj Khimii i Khimii Vody

    1980-06-01

    The methods of pH-potentiometry, conductometry, determination of residual concentrations of liquid phases and precipitations, selected by chemical analysis have been used for investigation R(NO/sub 3/)/sub 3/-(NH/sub 4/)/sub 2/WO/sub 2/-H/sub 2/O systems, (where R=Sc, Y, La). The formation of double tungstates NH/sub 4/R(WO/sub 4/)/sub 2/xnH/sub 2/O is established. The NH/sub 4/Sc(WO/sub 4/)/sub 2/x4.5H/sub 2/O, NH/sub 4/Yx(WO/sub 4/)/sub 2/x3H/sub 2/O, NH/sub 4/La(WO/sub 4/)/sub 2/x1.5H/sub 2/O compounds are synthesized in individual form. Precipitation conditions (pH, concentration ratio) and composition of the solid phase are determined. The behaviour of synthesized slats at thermolysis up to 880 deg C is studied. Physicochemical properties (color, solubility of the simple and double tungstates of scandium, yttrium and lanthanum with ammonium) is studied. IR spectra and X-ray diffraction analysis give idea about double salts structural transformations.

  2. Hydrogen storage in thin film magnesium-scandium alloys

    International Nuclear Information System (INIS)

    Niessen, R.A. H.; Notten, P.H. L.

    2005-01-01

    Thorough electrochemical materials research has been performed on thin films of novel magnesium-scandium hydrogen storage alloys. It was found that palladium-capped thin films of Mg x Sc (1-x) with different compositions (ranging from x=0.50 -0.90) show an increase in hydrogen storage capacity of more than 5-20% as compared to their bulk equivalents using even higher discharge rates. The maximum reversible hydrogen storage capacity at the optimal composition (Mg 80 Sc 20 ) amounts to 1795-bar mAh/g corresponding to a hydrogen content of 2.05 H/M or 6.7-bar wt.%, which is close to five times that of the commonly used hydride-forming materials in commercial NiMH batteries. Galvanostatic intermittent titration technique (GITT) measurements show that the equilibrium pressure during discharge is lower than that of bulk powders by one order of magnitude (10 -7 -bar mbar versus 10 -6 -bar mbar, respectively)

  3. The spectrum of four times ionized scandium, Sc V

    International Nuclear Information System (INIS)

    Smitt, R.; Ekberg, J.O.

    1985-01-01

    The spectrum of four times ionized scandium emitted from a sliding spark discharge has been observed using a 3 m normal incidence spectrograph and a 5 m grazing incidence spectrograph. About 450 lines in the wavelength region 160 A to 220 A have been identified as combinations between 46 odd levels belonging to the 3s 2 3p 5 , 3s 2 3p 4 4p and 3s3p 5 3d configurations and 72 even levels of the 3s3p 6 , 3s 2 3p 4 3d, 4d, 4s and 5s configurations. Of the previous identifications we have confirmed 18 levels. The level structure of the observed configurations has been theoretically interpreted by including configuration interaction effects. The inclusion of 3s 2 3p 3 3d 2 in the calculations of the odd parity configurations is found to be important. Almost all levels of 3s3p 5 3d show a considerable mixing with levels of 3s 2 3p 3 3d 2 , in some cases by as much as 50%. The energy parameters determined from least-squares fits to the observed level values are compared with Hartree-Fock calculations. The ionization energy is estimated to be 739 500 +- 1000 cm -1 . (91.65 +- 0,12 eV). (orig.)

  4. Aluminum-Scandium: A Material for Semiconductor Packaging

    Science.gov (United States)

    Geissler, Ute; Thomas, Sven; Schneider-Ramelow, Martin; Mukhopadhyay, Biswajit; Lang, Klaus-Dieter

    2016-10-01

    A well-known aluminum-scandium (Al-Sc) alloy, already used in lightweight sports equipment, is about to be established for use in electronic packaging. One application for Al-Sc alloy is manufacture of bonding wires. The special feature of the alloy is its ability to harden by precipitation. The new bonding wires with electrical conductivity similar to pure Al wires can be processed on common wire bonders for aluminum wedge/wedge (w/w) bonding. The wires exhibit very fine-grained microstructure. Small Al3Sc particles are the main reason for its high strength and prevent recrystallization and grain growth at higher temperatures (>150°C). After the wire-bonding process, the interface is well closed. Reliability investigations by active power cycling demonstrated considerably improved lifetime compared with pure Al heavy wires. Furthermore, the Al-Sc alloy was sputter-deposited onto silicon wafer to test it as chip metallization in copper (Cu) ball/wedge bonding technology. After deposition, the layers exhibited fine-grained columnar structure and small coherent Al3Sc particles with dimensions of a few nanometers. These particles inhibit softening processes such as Al splashing in fine wire bonding processes and increase the thickness of remnant Al under the copper balls to 85% of the initial thickness.

  5. Thermomechanical treatment of welded joints of aluminum-lithium alloys modified by scandium

    Science.gov (United States)

    Malikov, A. G.

    2017-12-01

    At present, the aeronautical equipment manufacture involves up-to-date high-strength aluminum alloys of decreased density resulting from the lithium admixture. Various technologies of fusible welding of these alloys are being developed. The paper presents experimental investigations of the optimization of the laser welding of aluminum alloys with the scandium-modified welded joint after thermomechanical treatment. The effect of scandium on the micro- and macrostructure is studied along with strength characteristics of the welded joint. It is found that thermomechanical treatment allows us to obtain the strength of the welded joint 0.89 for the Al-Mg-Li system and 0.99 for the Al-Cu-Li system with the welded joint modified by scandium in comparison with the base alloy after treatment.

  6. The enthalpy of solid scandium in the temperature range 406 - 1812 K

    International Nuclear Information System (INIS)

    Lyapunov, K.M.; Baginskij, A.V.; Stankus, S.V.

    2001-01-01

    Enthalpy of pure scandium was measured on massive calorimeter in the range from 406 to 1812 K by mixing method. The enthalpy of face centered close cubic lattice - body centered cubic lattice transformation is equal to ΔH t 4068 J/mol. Obtained value within the limits of error is compatible with the results given earlier (4009 J/mol). The dependence of the middle specific heat of scandium C p (T) on the temperature was shown in correlation with the results of other works. The results of the conducted experiments reinforce the conclusion made earlier about an absence (or a little) in the decomposition of an anharmonic component of the oscillation specific heat of scandium C p a (T) members proportional to the first or the second degrees of temperature [ru

  7. Biamperometric analysis of nonaqueous scandium solutions containing lanthanides, lead and thorium

    International Nuclear Information System (INIS)

    Gevorgyan, A.M.; Talipov, Sh.T.; Kostylev, V.S.; Khadeev, V.A.; Nadol'skij, M.Ya.

    1978-01-01

    Investigated was a possibility of direct scandium titration in the presence of large rare earth quantities, and also a possibility of complexonometric scandium and rare earth sum determination at their joint presence in non-aqueous acetic acid solution. The titration was carried out at electrode voltage of 0.95V, background electrolyte concentration of lithium perchlorate being 0.2M. Non-aqueous magnesium complexonate was used as titrating reagent. Th and Pb complexonates are shown to be less stable as compared to Sc complexonate, and consequently, Th and Pb ions must not interfere with biamperometric titration of Sc ion. A method applied to analysis of binary mixture, containing scandium, and a method for model alloy and thortveitite mineral was developed. Well reproducible and precise enough results are obtained in all the cases. Ions of Bi, Cu, Cd, Zn, In, Ga and Ti interfere with determination

  8. Pressure-induced structural change from hexagonal to fcc metal lattice in scandium trihydride

    International Nuclear Information System (INIS)

    Ohmura, A.; Machida, A.; Watanuki, T.; Aoki, K.; Nakano, S.; Takemura, K.

    2007-01-01

    We synthesized scandium hydrides by hydrogenation of a scandium foil with hydrogen fluid under high pressure at ambient temperature. Scandium dihydride (ScH 2 ) and trihydride (ScH 3 ) were prepared near 4 and 5 GPa, respectively. The hydrogenation process and pressure-induced structural changes in ScH 3 were investigated by synchrotron radiation X-ray diffraction measurements up to 54.7 GPa. A structural transition from hexagonal to the fcc lattice began at 30 GPa and was completed at 46 GPa via an intermediate state similar to those reported for other hexagonal trihydrides. The intermediate state was not interpreted in terms of a coexisting state for the low-pressure hexagonal and the high-pressure fcc structures. The onset transition pressure of ScH 3 supported the previously proposed relation that the hexagonal-fcc transition pressure is inversely proportional to the ionic radius of the trihydride

  9. How to use the cosmological Schwinger principle for energy flux, entropy, and 'atoms of space-time' to create a thermodynamic space-time and multiverse

    International Nuclear Information System (INIS)

    Beckwith, Andrew

    2011-01-01

    We make explicit an idea by Padmanabhan in DICE 2010, as to finding 'atoms of space-time' permitting a thermodynamic treatment of emergent structure similar to Gibbs treatment of statistical physics. That is, an ensemble of gravitons is used to give an 'atom' of space-time congruent with relic GW. The idea is to reduce the number of independent variables to get a simple emergent space-time structure of entropy. An electric field, based upon the cosmological Schwinger principle, is linked to relic heat flux, with entropy production tied in with candidates as to inflaton potentials. The effective electric field links with the Schwinger 1951s result of an E field leading to pairs of e + e - charges nucleated in space-time volume V · t. Note that in most inflationary models, the assumption is for a magnetic field, not an electric field. An electric field permits a kink-anti-kink construction of an emergent structure, which includes Glinka's recent pioneering approach to a Multiverse. Also an E field allows for an emergent relic particle frequency range between one and 100 GHz. The novel contribution is a relic E field, instead of a B field, in relic space-time 'atom' formation and vacuum nucleation of the same.

  10. Ghana Space Science and Technology Institute (GSSTI),Ghana Atomic Energy Commission: Annual Report 2013/2014

    International Nuclear Information System (INIS)

    2014-01-01

    The report presents the structure as well as the research projects of the newly established Ghana Space Science and Technology Institute of the Ghana Atomic Energy Commission from January to December 2014. Research projects listed are in the areas of Astronomy and Astrophysics; Remote Sensing; Electronics and Instrumentation; and Satellite Communication.

  11. Enhancement of phase space density by increasing trap anisotropy in a magneto-optical trap with a large number of atoms

    International Nuclear Information System (INIS)

    Vengalattore, M.; Conroy, R.S.; Prentiss, M.G.

    2004-01-01

    The phase space density of dense, cylindrical clouds of atoms in a 2D magneto-optic trap is investigated. For a large number of trapped atoms (>10 8 ), the density of a spherical cloud is limited by photon reabsorption. However, as the atom cloud is deformed to reduce the radial optical density, the temperature of the atoms decreases due to the suppression of multiple scattering leading to an increase in the phase space density. A density of 2x10 -4 has been achieved in a magneto-optic trap containing 2x10 8 atoms

  12. Scandium complexes with the tetraphenylethylene and anthracene dianions.

    Science.gov (United States)

    Ellis, John E; Minyaev, Mikhail E; Nifant'ev, Ilya E; Churakov, Andrei V

    2018-06-01

    The structural study of Sc complexes containing dianions of anthracene and tetraphenylethylene should shed some light on the nature of rare-earth metal-carbon bonding. The crystal structures of (18-crown-6)bis(tetrahydrofuran-κO)sodium bis(η 6 -1,1,2,2-tetraphenylethenediyl)scandium(III) tetrahydrofuran disolvate, [Na(C 4 H 8 O) 2 (C 12 H 24 O 6 )][Sc(C 26 H 20 ) 2 ]·2C 4 H 8 O or [Na(18-crown-6)(THF) 2 ][Sc(η 6 -C 2 Ph 4 ) 2 ]·2(THF), (1b), (η 5 -1,3-diphenylcyclopentadienyl)(tetrahydrofuran-κO)(η 6 -1,1,2,2-tetraphenylethenediyl)scandium(III) toluene hemisolvate, [Sc(C 17 H 13 )(C 26 H 20 )(C 4 H 8 O)]·0.5C 7 H 8 or [(η 5 -1,3-Ph 2 C 5 H 3 )Sc(η 6 -C 2 Ph 4 )(THF)]·0.5(toluene), (5b), poly[[(μ 2 -η 3 :η 3 -anthracenediyl)bis(η 6 -anthracenediyl)bis(η 5 -1,3-diphenylcyclopentadienyl)tetrakis(tetrahydrofuran)dipotassiumdiscandium(III)] tetrahydrofuran monosolvate], {[K 2 Sc 2 (C 14 H 10 ) 3 (C 17 H 13 ) 2 (C 4 H 8 O) 4 ]·C 4 H 8 O} n or [K(THF) 2 ] 2 [(1,3-Ph 2 C 5 H 3 ) 2 Sc 2 (C 14 H 10 ) 3 ]·THF, (6), and 1,4-diphenylcyclopenta-1,3-diene, C 17 H 14 , (3a), have been established. The [Sc(η 6 -C 2 Ph 4 ) 2 ] - complex anion in (1b) contains the tetraphenylethylene dianion in a symmetrical bis-η 3 -allyl coordination mode. The complex homoleptic [Sc(η 6 -C 2 Ph 4 ) 2 ] - anion retains its structure in THF solution, displaying hindered rotation of the coordinated phenyl rings. The 1D 1 H and 13 C{ 1 H}, and 2D COSY 1 H- 1 H and 13 C- 1 H NMR data are presented for M[Sc(Ph 4 C 2 ) 2 ]·xTHF [M = Na and x = 4 for (1a); M = K and x = 3.5 for (2a)] in THF-d 8 media. Complex (5b) exhibits an unsymmetrical bis-η 3 -allyl coordination mode of the dianion, but this changes to a η 4 coordination mode for (1,3-Ph 2 C 5 H 3 )Sc(Ph 4 C 2 )(THF) 2 , (5a), in THF-d 8 solution. A 45 Sc NMR study of (2a) and UV-Vis studies of (1a), (2a) and (5a) indicate a significant covalent contribution to the Sc-Ph 4 C 2 bond character. The unique Sc ate complex, (6

  13. First-principles real-space tight-binding LMTO calculation of electronic structures for atomic clusters

    International Nuclear Information System (INIS)

    Xie, Z.L.; Dy, K.S.; Wu, S.Y.

    1997-01-01

    A real-space scheme has been developed for a first-principles calculation of electronic structures and total energies of atomic clusters. The scheme is based on the combination of the tight-binding linear muffin-tin orbital (TBLMTO) method and the method of real-space Green close-quote s function. With this approach, the local electronic density of states can be conveniently determined from the real-space Green close-quote s function. Furthermore, the full electron density of a cluster can be directly calculated in real space. The scheme has been shown to be very efficient due to the incorporation of the method of real-space Green close-quote s function and Delley close-quote s method of evaluating multicenter integrals. copyright 1996 The American Physical Society

  14. Gadolinium scandium germanide, Gd2Sc3Ge4

    Directory of Open Access Journals (Sweden)

    Sumohan Misra

    2009-04-01

    Full Text Available Gd2Sc3Ge4 adopts the orthorhombic Pu5Rh4-type structure. The crystal structure contains six sites in the asymmetric unit: two sites are statistically occupied by rare-earth atoms with Gd:Sc ratios of 0.967 (4:0.033 (4 and 0.031 (3:0.969 (3, one site (.m. symmetry is occupied by Sc atoms, and three distinct sites (two of which with .m. symmetry are occupied by Ge atoms. The rare-earth atoms form two-dimensional slabs with Ge atoms occupying the trigonal-prismatic voids.

  15. Study of competitive complexing in scandium(3)-xylenol-orange-hydroxyethyliminodiacetic acid system

    International Nuclear Information System (INIS)

    Kornev, V.I.; Mukanov, I.P.; Artem'eva, O.A.

    1976-01-01

    The competitive complexing in the system scandium(3)-xylene orange (XO)-hydroxyethyliminodiacetic acid (H 3 L) has been studied. Ligands act as competitive particles. It has been established preliminarily that introduction of H 3 L into the solution containing a mixture of Sc and Xo changes considerably the absorption spectra of the coloured complex. Weakening of light absorption indicates that the coloured complex with XO is destructed and colourless hydroxyethyliminodiacetate of scandium is formed. The formation of scandium hydroxyethyliminoacetate has been studied spectrophotometrically by equilibrium between the complexes. The dependence of optical density on pH, when the concentrations of reagents are constant, as well as on concetration of H 3 L has been studied. The composition of the complex (1:1) formed at pH 3.2 has been established graphically and the constant of the complex ScHL + instability has been calculated (PKsub(H)=10.69+-0.45). It has been shown that H 3 L, when interacting with scandium, behaves as dibasic ligand. It is most probable that during complex formation the hydrogen ion of the hydroxygroup is not replaced, although the participation of hydroxygroup in coordination is possible due to a donor-acceptor bond

  16. Structural differences of half-sandwich complexes of scandium and yttrium containing bulky substituents

    Czech Academy of Sciences Publication Activity Database

    Fridrichová, Adéla; Růžička, A.; Lamač, Martin; Horáček, Michal

    2017-01-01

    Roč. 76, FEB 2017 (2017), s. 62-66 ISSN 1387-7003 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : scandium * yttrium * half-sandwich Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.640, year: 2016

  17. In situ observation of the reaction of scandium and carbon by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-Arellano, Erick A., E-mail: eajuarez@unpa.edu.m [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Winkler, Bjorn [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Vogel, Sven C. [Los Alamos National Laboratory, Lujan Center. Mail Stop H805, Los Alamos, NM 87545 (United States); Senyshyn, Anatoliy [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitaet Muenchen, Lichtenbergstr. 1, D-85747 Garching (Germany); Materialwissenschaft, TU Darmstadt, Petersensstr. 23, D-64287 Darmstadt (Germany); Kammler, Daniel R. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Avalos-Borja, Miguel [CNyN, UNAM, A. Postal 2681, Ensenada, B.C. (Mexico)

    2011-01-05

    Research highlights: {yields} Exist two ScC cubic phases with B1-structure type differing in site occupancy of C. {yields} A new orthorhombic scandium carbide phase is formed at 1473(50) K. {yields} The recrystallization of alpha-Sc occurs between 1000 and 1223 K. - Abstract: The formation of scandium carbides by reaction of the elements has been investigated by in situ neutron diffraction up to 1823 K. On heating, the recrystallization of {alpha}-Sc occurs between 1000 and 1223 K. The formation of Sc{sub 2}C and ScC (NaCl-B1 type structure) phases has been detected at 1323 and 1373 K, respectively. The formation of a new orthorhombic scandium carbide phase was observed at 1473(50) K. Once the scandium carbides are formed they are stable upon heating or cooling. No other phases were detected in the present study, in which the system was always carbon saturated. The thermal expansion coefficients of all phases have been determined, they are constant throughout the temperature interval studied.

  18. 4D Flexible Atom-Pairs: An efficient probabilistic conformational space comparison for ligand-based virtual screening

    Science.gov (United States)

    2011-01-01

    Background The performance of 3D-based virtual screening similarity functions is affected by the applied conformations of compounds. Therefore, the results of 3D approaches are often less robust than 2D approaches. The application of 3D methods on multiple conformer data sets normally reduces this weakness, but entails a significant computational overhead. Therefore, we developed a special conformational space encoding by means of Gaussian mixture models and a similarity function that operates on these models. The application of a model-based encoding allows an efficient comparison of the conformational space of compounds. Results Comparisons of our 4D flexible atom-pair approach with over 15 state-of-the-art 2D- and 3D-based virtual screening similarity functions on the 40 data sets of the Directory of Useful Decoys show a robust performance of our approach. Even 3D-based approaches that operate on multiple conformers yield inferior results. The 4D flexible atom-pair method achieves an averaged AUC value of 0.78 on the filtered Directory of Useful Decoys data sets. The best 2D- and 3D-based approaches of this study yield an AUC value of 0.74 and 0.72, respectively. As a result, the 4D flexible atom-pair approach achieves an average rank of 1.25 with respect to 15 other state-of-the-art similarity functions and four different evaluation metrics. Conclusions Our 4D method yields a robust performance on 40 pharmaceutically relevant targets. The conformational space encoding enables an efficient comparison of the conformational space. Therefore, the weakness of the 3D-based approaches on single conformations is circumvented. With over 100,000 similarity calculations on a single desktop CPU, the utilization of the 4D flexible atom-pair in real-world applications is feasible. PMID:21733172

  19. Ionization steps and phase-space metamorphoses in the pulsed microwave ionization of highly excited hydrogen atoms

    International Nuclear Information System (INIS)

    Bayfield, J.E.; Luie, S.Y.; Perotti, L.C.; Skrzypkowski, M.P.

    1996-01-01

    As the peak electric field of the microwave pulse is increased, steps in the classical microwave ionization probability of the highly excited hydrogen atom are produced by phase-space metamorphosis. They arise from new layers of Kolmogorov-Arnold-Moser (KAM) islands being exposed as KAM surfaces are destroyed. Both quantum numerical calculations and laboratory experiments exhibit the ionization steps, showing that such metamorphoses influence pulsed semiclassical systems. copyright 1996 The American Physical Society

  20. Atomic oxygen effects on boron nitride and silicon nitride: A comparison of ground based and space flight data

    Science.gov (United States)

    Cross, J. B.; Lan, E. H.; Smith, C. A.; Whatley, W. J.

    1990-01-01

    The effects of atomic oxygen on boron nitride (BN) and silicon nitride (Si3N4) were evaluated in a low Earth orbit (LEO) flight experiment and in a ground based simulation facility. In both the inflight and ground based experiments, these materials were coated on thin (approx. 250A) silver films, and the electrical resistance of the silver was measured in situ to detect any penetration of atomic oxygen through the BN and Si3N4 materials. In the presence of atomic oxygen, silver oxidizes to form silver oxide, which has a much higher electrical resistance than pure silver. Permeation of atomic oxygen through BN, as indicated by an increase in the electrical resistance of the silver underneath, was observed in both the inflight and ground based experiments. In contrast, no permeation of atomic oxygen through Si3N4 was observed in either the inflight or ground based experiments. The ground based results show good qualitative correlation with the LEO flight results, indicating that ground based facilities such as the one at Los Alamos National Lab can reproduce space flight data from LEO.

  1. Comparison of Atom Interferometers and Light Interferometers as Space-Based Gravitational Wave Detectors

    Science.gov (United States)

    Baker, John G.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

  2. On the retrieval of crystallographic information from atom probe microscopy data via signal mapping from the detector coordinate space.

    Science.gov (United States)

    Wallace, Nathan D; Ceguerra, Anna V; Breen, Andrew J; Ringer, Simon P

    2018-06-01

    Atom probe tomography is a powerful microscopy technique capable of reconstructing the 3D position and chemical identity of millions of atoms within engineering materials, at the atomic level. Crystallographic information contained within the data is particularly valuable for the purposes of reconstruction calibration and grain boundary analysis. Typically, analysing this data is a manual, time-consuming and error prone process. In many cases, the crystallographic signal is so weak that it is difficult to detect at all. In this study, a new automated signal processing methodology is demonstrated. We use the affine properties of the detector coordinate space, or the 'detector stack', as the basis for our calculations. The methodological framework and the visualisation tools are shown to be superior to the standard method of crystallographic pole visualisation directly from field evaporation images and there is no requirement for iterations between a full real-space initial tomographic reconstruction and the detector stack. The mapping approaches are demonstrated for aluminium, tungsten, magnesium and molybdenum. Implications for reconstruction calibration, accuracy of crystallographic measurements, reliability and repeatability are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Electromagnetically induced transparency in a Zeeman-sublevels Λ-system of cold 87Rb atoms in free space

    International Nuclear Information System (INIS)

    Jiang Xiaojun; Zhang Haichao; Wang Yuzhu

    2016-01-01

    We report the experimental investigation of electromagnetically induced transparency (EIT) in a Zeeman-sublevels Λ-type system of cold 87 Rb atoms in free space. We use the Zeeman substates of the hyperfine energy states 5 2 S 1/2 , F = 2 and 5 2 P 3/2 , F′ = 2 of 87 Rb D 2 line to form a Λ-type EIT scheme. The EIT signal is obtained by scanning the probe light over 1 MHz in 4 ms with an 80 MHz arbitrary waveform generator. More than 97% transparency and 100 kHz EIT window are observed. This EIT scheme is suited for an application of pulsed coherent storage atom clock (Yan B, et al. 2009 Phys. Rev. A 79 063820). (paper)

  4. Hydrogen atom in space with a compactified extra dimension and potential defined by Gauss' law

    Czech Academy of Sciences Publication Activity Database

    Bureš, M.; Siegl, Petr

    2015-01-01

    Roč. 354, MAR (2015), s. 316-327 ISSN 0003-4916 Grant - others:GA ČR(CZ) GD202/08/H072 Institutional support: RVO:61389005 Keywords : extra dimensions * hydrogen atom * quantum stability Subject RIV: BE - Theoretical Physics Impact factor: 2.375, year: 2015

  5. Process Design Aspects for Scandium-Selective Leaching of Bauxite Residue with Sulfuric Acid

    OpenAIRE

    Konstantinos Hatzilyberis; Theopisti Lymperopoulou; Lamprini-Areti Tsakanika; Klaus-Michael Ochsenkühn; Paraskevas Georgiou; Nikolaos Defteraios; Fotios Tsopelas; Maria Ochsenkühn-Petropoulou

    2018-01-01

    Aiming at the industrial scale development of a Scandium (Sc)-selective leaching process of Bauxite Residue (BR), a set of process design aspects has been investigated. The interpretation of experimental data for Sc leaching yield, with sulfuric acid as the leaching solvent, has shown significant impact from acid feed concentration, mixing time, liquid to solids ratio (L/S), and number of cycles of leachate re-usage onto fresh BR. The thin film diffusion model, as the fundamental theory for l...

  6. Pilot-scale recovery of rare earths and scandium from phosphogypsum and uranium leachates

    Directory of Open Access Journals (Sweden)

    Mashkovtsev Maxim

    2016-01-01

    Full Text Available Ural Federal University (UrFU and VTT have performed joint research on development of industrial technologies for the extraction of REM and Scandium compounds from phosphogypsum and Uranium ISL leachate solutions. Leaching-absorption experiments at UrFU have been supported with multicomponent solution modelling by VTT. The simulations have been performed with VTT’s ChemSheet/Balas program and can be used for speciation calculations in the lixiviant solution. The experimental work combines solvent extraction with advanced ion exchange methodology in a pilot facility capable of treating 5 m3 solution per hour. Currently, the plant produces cerium carbonate, lanthanum oxide, neodymium oxide and concentrate of heavy rare earth metals. A batch of 45 t solids has been processed with the gain of 100 kg’s of REM concentrate. A mini-pilot plant with productivity above 50 liters per hour has been applied to recover scandium oxide and REE concentrates from the uranium ISL solution. As the preliminary product contains radioactivity (mainly strontium, an additional decontamination and cleaning of both concentrates by extraction has rendered a necessity. Finally a purified 99% concentrate of scandium oxide as well as 99% rare earth concentrate are received.

  7. Effect of scandium on the phase composition and mechanical properties of ABM alloys

    Science.gov (United States)

    Molchanova, L. V.

    2010-09-01

    The effect of scandium on the composition and mechanical properties of ABM-1 alloys (Al-30% Be-5% Mg) is studied. The scandium content is varied from 0.1 to 0.5 wt %. It is established that, in the studied part of the Al-Be-Mg-Sc system, an aluminum solid solution (Al) and the ScBe13 compound are in equilibrium with a beryllium solid solution (Be). Magnesium dissolves in both the aluminum component and the ScBe13 compound. The strengthening effect related to the decomposition of the solid solution and the precipitation of Al3Sc cannot be extended to the strengthening of ABM-type alloys. Additions of 0.1-0.15 wt % Sc only weakly improve the mechanical properties of the alloys due to the refinement of beryllium-component grains. At high scandium contents, the strength increases insignificantly due to primary precipitation of ScBe13 and the plasticity decreases simultaneously.

  8. Influence of scandium on the pitting behaviour of Al-Zn-Mg-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wloka, J. [Department of Materials Sciences, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen (Germany); Virtanen, S. [Department of Materials Sciences, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen (Germany)], E-mail: virtanen@ww.uni-erlangen.de

    2007-11-15

    In this paper the influence of small scandium additions (<0.26 wt.%) on the corrosion properties of the high-strength Al-Zn-Mg-Cu alloy AA7010 is investigated. The addition of scandium (in combination with the grain refiner Zr) leads to the formation of Al{sub 3}Sc{sub x}Zr{sub 1-x} phases. These coarse particles disturb the grain structure near the particle/matrix interface, which facilitates the initiation of localized corrosion in potentio-dynamic scans. Microelectrochemical investigations revealed a slightly cathodic character of these particles and a passive range beyond the breakdown potential of the matrix. Mass loss measurements show that the addition of scandium increases the mass loss during the initial period. The corrosion morphology was investigated with optical and scanning electron microscopy. The composition of the phases was determined with energy-dispersive X-ray analysis. Micro-capillary measurements were performed to investigate the electrochemical properties of single phases surrounded by matrix.

  9. Thermal, spectroscopic and laser properties of Nd3+ in gadolinium scandium gallium garnet crystal produced by optical floating zone method

    Science.gov (United States)

    Tian, Li; Wang, Shuxian; Wu, Kui; Wang, Baolin; Yu, Haohai; Zhang, Huaijin; Cai, Huaqiang; Huang, Hui

    2013-12-01

    A neodymium-doped gadolinium scandium gallium garnet (Nd:GSGG) single crystal with dimensions of Φ 5 × 20 mm2 has been grown by means of optical floating zone (OFZ). X-ray powder diffraction (XRPD) result shows that the as-grown Nd:GSGG crystal possesses a cubic structure with space group Ia3d and a cell parameter of a = 1.2561 nm. Effective elemental segregation coefficients of the Nd:GSGG as-grown crystal were calculated by using X-ray fluorescence (XRF). The thermal properties of the Nd:GSGG crystal were systematically studied by measuring the specific heat, thermal expansion and thermal diffusion coefficient, and the thermal conductivity of this crystal was calculated. The absorption and luminescence spectra of Nd:GSGG were measured at room temperature (RT). By using the Judd-Ofelt (J-O) theory, the theoretical radiative lifetime was calculated and compared with the experimental result. Continuous wave (CW) laser performance was achieved with the Nd:GSGG at the wavelength of 1062 nm when it was pumped by a laser diode (LD). A maximum output power of 0.792 W at 1062 nm was obtained with a slope efficiency of 11.89% under a pump power of 7.36 W, and an optical-optical conversion efficiency of 11.72%.

  10. Phase-space curvature in spin-orbit-coupled ultracold atomic systems

    Science.gov (United States)

    Armaitis, J.; Ruseckas, J.; Anisimovas, E.

    2017-04-01

    We consider a system with spin-orbit coupling and derive equations of motion which include the effects of Berry curvatures. We apply these equations to investigate the dynamics of particles with equal Rashba-Dresselhaus spin-orbit coupling in one dimension. In our derivation, the adiabatic transformation is performed first and leads to quantum Heisenberg equations of motion for momentum and position operators. These equations explicitly contain position-space, momentum-space, and phase-space Berry curvature terms. Subsequently, we perform the semiclassical approximation and obtain the semiclassical equations of motion. Taking the low-Berry-curvature limit results in equations that can be directly compared to previous results for the motion of wave packets. Finally, we show that in the semiclassical regime, the effective mass of the equal Rashba-Dresselhaus spin-orbit-coupled system can be viewed as a direct effect of the phase-space Berry curvature.

  11. Polar and chemical domain structures of lead scandium tantalate (PST)

    International Nuclear Information System (INIS)

    Peng, J.L.; Bursill, L.A.

    1993-01-01

    The local structure of chemical and polar domains and domain walls is determined directly by atomic resolution high-resolution electron microscopy. Thus the Pb, Ta and Sc atomic positions may be located in the images of very thin crystals. Furthermore the Pb cation displacements away from the ideal perovskite A-site have been measured directly for the first time. Local variations in polarization direction may be mapped directly off the images, provided certain electron optical conditions are met. The results are relevant to recent theories of polar-glass behaviour in relaxor-type complex oxide functional ceramics. 17 refs., 9 figs

  12. Solvent extraction of tricomponent complexes of zirconium and scandium with salicylic acid and collidine

    International Nuclear Information System (INIS)

    Kochetkova, S.K.; Fadeeva, V.I.; Kalistratova, V.P.

    1976-01-01

    Extraction of tricomponent compounds of zirconium and scandium with salicylic acid (Sal) and collidine (Col) has been studied. Addition of Col widens considerably the pH range of maximum extraction of zirconium salicylate and makes it possible to extract quantitatively both zirconium and scandium in the following pH range: scandium at pH 3.8-5.2; zirconium at pH 2-4. Optimum concentrations of salicylic acid and collidine are 0.05 mol/l and 0.375 mol/l, respectively. The composition of the complexes being extracted has been studied by the shift equilibrium method. Chloroform extracts complexes having the ratio Zr:Sal:Col=1:2:1(pH=3); Sc:Sal:Col=1:3:1(pH=4), and 1:2:1(pH=5). The composition of the complexes being formed is assumed to be [Zr(OH) 3 (HSal) 2 ] - [ColH + ] (pH=3); Sc(HSal) 3 xCol (pH=4.0); Sc(OH)(HSal) 2 xCol (pH=5.0). Extraction of collidine-salicylate complexes of Hf, Th, La, and Y under the conditions of optimum extraction of zirconium and scandium has been investigated when concentration of Zr and Sc in the solution is 3.0.10μ- 5 -1.37.10 -4 mol/l, respectively. It has been shown that hafnium is extracted quantitatively (95-100%) at pH 2.3-4.6; thorium at pH 3.0-6.4; 60% of yttrium is extracted at pH 4.0-4.8; 25% of lanthanum is extracted at pH 3.3-4.9. At pH 2.0 it is possible to separate Zr from Sc,Y, and La; at pH 1.4-1.5 from small amounts of Hf and Tn. Separation of zirconium, from small amounts of hafnium, 10-fold amounts of thorium, 100-fold amounts of scandium and lanthanum is also possible

  13. Solvent extraction of tricomponent complexes of zirconium and scandium with salicylic acid and collidine

    Energy Technology Data Exchange (ETDEWEB)

    Kochetkova, S K; Fadeeva, V I; Kalistratova, V P [Moskovskij Gosudarstvennyj Univ. (USSR)

    1976-01-01

    Extraction of tricomponent compounds of zirconium and scandium with salicylic acid (Sal) and collidine (Col) has been studied. Addition of Col widens considerably the pH range of maximum extraction of zirconium salicylate and makes it possible to extract quantitatively both zirconium and scandium in the following pH range: scandium at pH 3.8-5.2; zirconium at pH 2-4. Optimum concentrations of salicylic acid and collidine are 0.05 mol/l and 0.375 mol/l, respectively. The composition of the complexes being extracted has been studied by the shift equilibrium method. Chloroform extracts complexes having the ratio Zr:Sal:Col=1:2:1(pH=3); Sc:Sal:Col=1:3:1(pH=4), and 1:2:1(pH=5). The composition of the complexes being formed is assumed to be (Zr(OH)/sub 3/(HSal)/sub 2/)/sup -/(ColH/sup +/) (pH=3); Sc(HSal)/sub 3/xCol (pH=4.0); Sc(OH)(HSal)/sub 2/xCol (pH=5.0). Extraction of collidine-salicylate complexes of Hf, Th, La, and Y under the conditions of optimum extraction of zirconium and scandium has been investigated when concentration of Zr and Sc in the solution is 3.0.10..mu..-/sup 5/-1.37.10/sup -4/ mol/l, respectively. It has been shown that hafnium is extracted quantitatively (95-100%) at pH 2.3-4.6; thorium at pH 3.0-6.4; 60% of yttrium is extracted at pH 4.0-4.8; 25% of lanthanum is extracted at pH 3.3-4.9. At pH 2.0 it is possible to separate Zr from Sc,Y, and La; at pH 1.4-1.5 from small amounts of Hf and Tn. Separation of zirconium, from small amounts of hafnium, 10-fold amounts of thorium, 100-fold amounts of scandium and lanthanum is also possible.

  14. Classical Monopoles: Newton, NUT-space, gravomagnetic lensing and atomic spectra

    OpenAIRE

    Lynden-Bell, Donald; Nouri-Zonoz, Mohammad

    1996-01-01

    Stimulated by a scholium in Newton's Principia we find some beautiful results in classical mechanics which can be interpreted in terms of the orbits in the field of a mass endowed with a gravomagnetic monopole. All the orbits lie on cones! When the cones are slit open and flattened the orbits are exactly the ellipses and hyperbolae that one would have obtained without the gravomagnetic monopole. The beauty and simplicity of these results has led us to explore the similar problems in Atomic Ph...

  15. Two anionically derivatized scandium oxoselenates(IV): ScF[SeO3] and Sc2O2[SeO3

    Science.gov (United States)

    Greiner, Stefan; Chou, Sheng-Chun; Schleid, Thomas

    2017-02-01

    Scandium fluoride oxoselenate(IV) ScF[SeO3] and scandium oxide oxoselenate(IV) Sc2O2[SeO3] could be synthesized through solid-state reactions. ScF[SeO3] was obtained phase-pure, by reacting mixtures of Sc2O3, ScF3 and SeO2 (molar ratio: 1:1:3) together with CsBr as fluxing agent in corundum crucibles embedded into evacuated glassy silica ampoules after firing at 700 °C for seven days. Sc2O2[SeO3] first emerged as by-product during the attempts to synthesize ScCl[SeO3] following aforementioned synthesis route and could later be reproduced from appropriate Sc2O3/SeO3 mixtures. ScF[SeO3] crystallizes monoclinically in space group P21/m with a=406.43(2), b =661.09(4), c=632.35(4) pm, β=93.298(3)° and Z=2. Sc2O2[SeO3] also crystallizes in the monoclinic system, but in space group P21/n with a=786.02(6), b=527.98(4), c=1086.11(8) pm, β=108.672(3)° for Z=4. The crystal structures of both compounds are strongly influenced by the stereochemically active lone pairs of the ψ1-tetrahedral [SeO3]2- anions. They also show partial structures, where the derivatizing F- or O2- anions play an important role. For ScF[SeO3] chains of the composition 2+∞ 1[FS c 2 / 2 ] form from connected [FSc2]5+ dumbbells, while [OSc3]7+ pyramids and [OSc4]10+ tetrahedra units are condensed to layers according to 2+ ∞ 2[O2Sc2 ] in Sc2O2[SeO3].

  16. Dynamics of space and polarization charges of ferroelectric thin films measured by atomic force microscopy

    International Nuclear Information System (INIS)

    Oh, Y.J.; Lee, J.H.; Jo, W.

    2006-01-01

    Retention behavior and local hysteresis characteristics in Pb(Zr 0.52 Ti 0.48 )O 3 (PZT) thin films on Pt electrodes have been investigated by electrostatic force microscopy (EFM). A sol-gel method is used to synthesize PZT thin films and drying conditions are carefully explored over a wide range of temperature. Decay and retention mechanisms of single-poled and reverse-poled regions of the ferroelectric thin films are explained by space charge redistribution. Trapping behavior of space charges is dependent on the nature of interface between ferroelectric thin films and bottom electrodes. Local measurement of polarization-electric field curves by EFM shows inhomogeneous space charge entrapment

  17. PAREMD: A parallel program for the evaluation of momentum space properties of atoms and molecules

    Science.gov (United States)

    Meena, Deep Raj; Gadre, Shridhar R.; Balanarayan, P.

    2018-03-01

    The present work describes a code for evaluating the electron momentum density (EMD), its moments and the associated Shannon information entropy for a multi-electron molecular system. The code works specifically for electronic wave functions obtained from traditional electronic structure packages such as GAMESS and GAUSSIAN. For the momentum space orbitals, the general expression for Gaussian basis sets in position space is analytically Fourier transformed to momentum space Gaussian basis functions. The molecular orbital coefficients of the wave function are taken as an input from the output file of the electronic structure calculation. The analytic expressions of EMD are evaluated over a fine grid and the accuracy of the code is verified by a normalization check and a numerical kinetic energy evaluation which is compared with the analytic kinetic energy given by the electronic structure package. Apart from electron momentum density, electron density in position space has also been integrated into this package. The program is written in C++ and is executed through a Shell script. It is also tuned for multicore machines with shared memory through OpenMP. The program has been tested for a variety of molecules and correlated methods such as CISD, Møller-Plesset second order (MP2) theory and density functional methods. For correlated methods, the PAREMD program uses natural spin orbitals as an input. The program has been benchmarked for a variety of Gaussian basis sets for different molecules showing a linear speedup on a parallel architecture.

  18. Hg-201 (+) CO-Magnetometer for HG-199(+) Trapped Ion Space Atomic Clocks

    Science.gov (United States)

    Burt, Eric A. (Inventor); Taghavi, Shervin (Inventor); Tjoelker, Robert L. (Inventor)

    2011-01-01

    Local magnetic field strength in a trapped ion atomic clock is measured in real time, with high accuracy and without degrading clock performance, and the measurement is used to compensate for ambient magnetic field perturbations. First and second isotopes of an element are co-located within the linear ion trap. The first isotope has a resonant microwave transition between two hyperfine energy states, and the second isotope has a resonant Zeeman transition. Optical sources emit ultraviolet light that optically pump both isotopes. A microwave radiation source simultaneously emits microwave fields resonant with the first isotope's clock transition and the second isotope's Zeeman transition, and an optical detector measures the fluorescence from optically pumping both isotopes. The second isotope's Zeeman transition provides the measure of magnetic field strength, and the measurement is used to compensate the first isotope's clock transition or to adjust the applied C-field to reduce the effects of ambient magnetic field perturbations.

  19. Ubiquitous atom

    International Nuclear Information System (INIS)

    Spruch, G.M.; Spruch, L.

    1974-01-01

    The fundamentals of modern physics, including the basic physics and chemistry of the atom, elementary particles, cosmology, periodicity, and recent advances, are surveyed. The biology and chemistry of the life process is discussed to provide a background for considering the effects of atomic particles on living things. The uses of atomic power in space travel, merchant shipping, food preservation, desalination, and nuclear clocks are explored. (Pollut. Abstr.)

  20. Hardening mechanisms of spray formed Al-Zn-Mg-Cu alloys with scandium and other elemental additions

    International Nuclear Information System (INIS)

    Sharma, M.M.; Amateau, M.F.; Eden, T.J.

    2006-01-01

    The hardening mechanisms in spray formed Al-Zn-Mg-Cu alloys with additions of chromium, zinc and scandium were studied. The microstructure of the spray formed alloys was analyzed by transmission electron microscopy. A range of tensile strengths were achieved, and varied based on elemental additions, and second phase particle strengthening. To explain the significantly higher strength in one alloy with scandium, theoretical results due to the yield stress of Al-Zn-Mg-Cu alloys as a function of volume fraction and precipitate particle size, were compared to experimental data. Both the possibilities of coherency and order strengthening are examined. The significant additional hardening achieved in the alloy with scandium is attributed to small ordered particles of Al 3 Sc, which precipitated during aging

  1. Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films

    International Nuclear Information System (INIS)

    Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A.

    2011-01-01

    The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

  2. Simulated non-contact atomic force microscopy for GaAs surfaces based on real-space pseudopotentials

    International Nuclear Information System (INIS)

    Kim, Minjung; Chelikowsky, James R.

    2014-01-01

    We simulate non-contact atomic force microscopy (AFM) with a GaAs(1 1 0) surface using a real-space ab initio pseudopotential method. While most ab initio simulations include an explicit model for the AFM tip, our method does not introduce the tip modeling step. This approach results in a considerable reduction of computational work, and also provides complete AFM images, which can be directly compared to experiment. By analyzing tip-surface interaction forces in both our results and previous ab initio simulations, we find that our method provides very similar force profile to the pure Si tip results. We conclude that our method works well for systems in which the tip is not chemically active.

  3. The influence of the diluent nature on scandium extraction by the phenol-formaldehyde resol oligomer yarrezin B

    International Nuclear Information System (INIS)

    Semenov, S.A.; Valkina, E.M.; Reznik, A.M.

    1996-01-01

    The paper studies the effect of diluent nature on scandium extraction by Yarrezin B phenol-formaldehyde resol oligomer using n-octan, toluene, chloroform, n-octanol and kerosene as an example. Correlation coefficients of dependences of scandium distribution factor on some parameters of diluents are calculated. Possibility to use some parameters of diluents to predict their effect on extraction indices is determined. Hildebrandt solubility parameter of extracting agent and parameters of extracting agent-diluent interaction according to Flory-Haggins are calculated. 13 refs., 2 figs., 4 tabs

  4. A Space Experiment to Measure the Atomic Oxygen Erosion of Polymers and Demonstrate a Technique to Identify Sources of Silicone Contamination

    Science.gov (United States)

    Banks, Bruce A.; deGroh, Kim K.; Baney-Barton, Elyse; Sechkar, Edward A.; Hunt, Patricia K.; Willoughby, Alan; Bemer, Meagan; Hope, Stephanie; Koo, Julie; Kaminski, Carolyn; hide

    1999-01-01

    A low Earth orbital space experiment entitled, "Polymers Erosion And Contamination Experiment", (PEACE) has been designed as a Get-Away Special (GAS Can) experiment to be accommodated as a Shuttle in-bay environmental exposure experiment. The first objective is to measure the atomic oxygen erosion yields of approximately 40 different polymeric materials by mass loss and erosion measurements using atomic force microscopy. The second objective is to evaluate the capability of identifying sources of silicone contamination through the use of a pin-hole contamination camera which utilizes environmental atomic oxygen to produce a contaminant source image on an optical substrate.

  5. Derivation of a configuration space Hamiltonian for heavy atoms: three body potentials

    International Nuclear Information System (INIS)

    Mittleman, M.H.

    1981-01-01

    A brief history of the difficulties associated with the derivation of a configuration space Hamiltonian is presented. One of the problems encountered is the definition of the projection operators which must occur. A variational definition is obtained and, with simplifying assumptions, the optimum projection operators are those which project onto Hartree-Fock orbitals. This puts many previously performed numerical calculations on a firm footing. The form of the two body interactions is discussed in the context of the gauge freedom. The Coulomb gauge is the favored one but it is pointed out that it has never been proven to be the best one. Finally a form for the relativistic three election potential is given and the possibility of its observation is discussed

  6. Determination of aluminium, scandium and rare earth elements by emission flame spectrometry

    International Nuclear Information System (INIS)

    Otruba, V.; Sommer, L.

    1989-01-01

    Emission spectrometry in nitrous oxide-acetylene flames in combination with a highly resolving double monochromator and sensitive detecting system enables simple, sensitive and selective determinations of aluminium, scandium and all rare earth elements with exception of cerium in complicated matrices. Calibration plots are linear for a large concentration interval (≤ 100 μgxml -1 ), detection limits are in ngxml -1 level and RSD does not exceed 3% on the optimal concentration level of the particular element. The determination of Al, Sc, Eu and Yb showed particular advantages as to methods using ICP-spectrometry. (orig.)

  7. 3He release characteristics of metal tritides and scandium--tritium solid solutions

    International Nuclear Information System (INIS)

    Perkins, W.G.; Kass, W.J.; Beavis, L.C.

    1975-01-01

    Tritides of such metals as scandium, titanium, and erbium are useful materials for determining the effects of helium accumulation in metallic solids, for example, CTR first wall materials. Such effects include lattice strain and gross deformation, as reported elsewhere, which are related to 3 He retention and ultimate release. Long term gas release studies have indicated that, during the early life of a metal ditritide, a large fraction of the 3 He is retained in the solid. At more advanced ages (2 to 4 years, depending on the parent metal), the 3 He release rate becomes comparable to the generation rate. Statistical analysis of the data indicates that the acceleration in 3 He release rate depends on accumulated 3 He concentration rather than strictly on age. 3 He outgassing results are presented for thin films of ScT 2 , TiT 2 , and ErT 2 , and the critical 3 He concentrations are discussed in terms of a percolation model. Phase transformations which occur on tritide formation cast some doubt on the validity of extrapolating results obtained for metal tritides to predictions regarding the accumulation of helium in metals. Scandium is unique among the early transition and rare-earth metals in that the metal exhibits a very high room temperature tritium solubility (T/Sc = 0.4) with no phase transformation. Indeed, even the lattice parameters of the hcp scandium lattice are only minimally changed by tritium solution, and we have succeeded in obtaining single crystal ScT 0 . 3 samples in two crystallographic orientations. Using a very sensitive technique, we have measured 3 He emission from both these samples, as well as from fine-grained thin film scandium-tritium solid solution samples (ScT 0 . 3 - 0 . 4 ). The fine-grained film samples release 3 He at 2 to 3 percent of the generation rate, while the emission rate from the single-crystal samples is approximately 0.05 percent of the generation rate, indicating a strong grain size effect

  8. Scandium-doped zinc cadmium oxide as a new stable n-type oxide thermoelectric material

    DEFF Research Database (Denmark)

    Han, Li; Christensen, Dennis Valbjørn; Bhowmik, Arghya

    2016-01-01

    Scandium-doped zinc cadmium oxide (Sc-doped ZnCdO) is proposed as a new n-type oxide thermoelectric material. The material is sintered in air to maintain the oxygen stoichiometry and avoid instability issues. The successful alloying of CdO with ZnO at a molar ratio of 1 : 9 significantly reduced...... is a good candidate for improving the overall conversion efficiencies in oxide thermoelectric modules. Meanwhile, Sc-doped ZnCdO is robust in air at high temperatures, whereas other n-type materials, such as Al-doped ZnO, will experience rapid degradation of their electrical conductivity and ZT....

  9. Scandium sorption by immobilized microdispersed forms of phosporus-containing ion exchangers

    International Nuclear Information System (INIS)

    Sokolova, Yu.V.; Kurdyumov, G.M.; Smirnov, A.V.; Mezhirov, M.S.

    1991-01-01

    The possibility to improve considerably kinetics of scandium sorption by phosphate ion exchangers, immobilized into polyacrylonitrile (PAN) fibers, as compared with granular samples of ion exchangers, was shown. The influence of dispersion degree of immobilized ionite particles on sorption rate was studied. It is ascertained that the ionite grinding to the particle size ≤ 52 μm is sufficient for the rate increase by 1-1.5 orders. A lower swelling of the immobilized ion exchanger is its additional advantage as compared with granular form

  10. Dynamics of atoms in strong laser fields I: A quasi analytical model in momentum space based on a Sturmian expansion of the interacting nonlocal Coulomb potential

    Science.gov (United States)

    Ongonwou, F.; Tetchou Nganso, H. M.; Ekogo, T. B.; Kwato Njock, M. G.

    2016-12-01

    In this study we present a model that we have formulated in the momentum space to describe atoms interacting with intense laser fields. As a further step, it follows our recent theoretical approach in which the kernel of the reciprocal-space time-dependent Schrödinger equation (TDSE) is replaced by a finite sum of separable potentials, each of them supporting one bound state of atomic hydrogen (Tetchou Nganso et al. 2013). The key point of the model is that the nonlocal interacting Coulomb potential is expanded in a Coulomb Sturmian basis set derived itself from a Sturmian representation of Bessel functions of the first kind in the position space. As a result, this decomposition allows a simple spectral treatment of the TDSE in the momentum space. In order to illustrate the credibility of the model, we have considered the test case of atomic hydrogen driven by a linearly polarized laser pulse, and have evaluated analytically matrix elements of the atomic Hamiltonian and dipole coupling interaction. For various regimes of the laser parameters used in computations our results are in very good agreement with data obtained from other time-dependent calculations.

  11. Dynamics of atoms in strong laser fields I: A quasi analytical model in momentum space based on a Sturmian expansion of the interacting nonlocal Coulomb potential

    Energy Technology Data Exchange (ETDEWEB)

    Ongonwou, F., E-mail: fred.ongonwou@gmail.com [Département de Physique, Faculté des Sciences, Université des Sciences et Techniques de Masuku, B.P. 943 Franceville (Gabon); Tetchou Nganso, H.M., E-mail: htetchou@yahoo.com [Atoms and Molecules Laboratory, Centre for Atomic Molecular Physics and Quantum Optics (CEPAMOQ), Faculty of Science, University of Douala, P.O. Box 8580, Douala (Cameroon); Ekogo, T.B., E-mail: tekogo@yahoo.fr [Département de Physique, Faculté des Sciences, Université des Sciences et Techniques de Masuku, B.P. 943 Franceville (Gabon); Kwato Njock, M.G., E-mail: mkwato@yahoo.com [Atoms and Molecules Laboratory, Centre for Atomic Molecular Physics and Quantum Optics (CEPAMOQ), Faculty of Science, University of Douala, P.O. Box 8580, Douala (Cameroon)

    2016-12-15

    In this study we present a model that we have formulated in the momentum space to describe atoms interacting with intense laser fields. As a further step, it follows our recent theoretical approach in which the kernel of the reciprocal-space time-dependent Schrödinger equation (TDSE) is replaced by a finite sum of separable potentials, each of them supporting one bound state of atomic hydrogen (Tetchou Nganso et al. 2013). The key point of the model is that the nonlocal interacting Coulomb potential is expanded in a Coulomb Sturmian basis set derived itself from a Sturmian representation of Bessel functions of the first kind in the position space. As a result, this decomposition allows a simple spectral treatment of the TDSE in the momentum space. In order to illustrate the credibility of the model, we have considered the test case of atomic hydrogen driven by a linearly polarized laser pulse, and have evaluated analytically matrix elements of the atomic Hamiltonian and dipole coupling interaction. For various regimes of the laser parameters used in computations our results are in very good agreement with data obtained from other time-dependent calculations.

  12. Explicit Hilbert-space representations of atomic and molecular photoabsorption spectra: Computational studies of Stieltjes-Tchebycheff functions

    International Nuclear Information System (INIS)

    Hermann, M.R.; Langhoff, P.W.

    1983-01-01

    Explicit Hilbert-space techniques are reported for construction of the discrete and continuum Schroedinger states required in atomic and molecular photoexcitation and/or photoionization studies. These developments extend and clarify previously described moment-theory methods for determinations of photoabsorption cross sections from discrete basis-set calculations to include explicit construction of underlying wave functions. The appropriate Stieltjes-Tchebycheff excitation and ionization functions of nth order are defined as Radau-type eigenstates of an appropriate operator in an n-term Cauchy-Lanczos basis. The energies of these states are the Radau quadrature points of the photoabsorption cross section, and their (reciprocal) norms provide the corresponding quadrature weights. Although finite-order Stieltjes-Tchebycheff functions are L 2 integrable, and do not have asymptotic spatial tails in the continuous spectrum, the Radau quadrature weights nevertheless provide information for normalization in the conventional Dirac delta-function sense. Since one Radau point can be placed anywhere in the spectrum, appropriately normalized convergent approximations to any of the discrete or continuum Schroedinger states are obtained from the development. Connections with matrix partitioning methods are established, demonstrating that nth-order Stieltjes-Tchebycheff functions are optical-potential solutions of the matrix Schroedinger equation in the full Cauchy-Lanczos basis

  13. A Narrow-Linewidth Atomic Line Filter for Free Space Quantum Key Distribution under Daytime Atmospheric Conditions

    Science.gov (United States)

    Brown, Justin; Woolf, David; Hensley, Joel

    2016-05-01

    Quantum key distribution can provide secure optical data links using the established BB84 protocol, though solar backgrounds severely limit the performance through free space. Several approaches to reduce the solar background include time-gating the photon signal, limiting the field of view through geometrical design of the optical system, and spectral rejection using interference filters. Despite optimization of these parameters, the solar background continues to dominate under daytime atmospheric conditions. We demonstrate an improved spectral filter by replacing the interference filter (Δν ~ 50 GHz) with an atomic line filter (Δν ~ 1 GHz) based on optical rotation of linearly polarized light through a warm Rb vapor. By controlling the magnetic field and the optical depth of the vapor, a spectrally narrow region can be transmitted between crossed polarizers. We find that the transmission is more complex than a single peak and evaluate peak transmission as well as a ratio of peak transmission to average transmission of the local spectrum. We compare filters containing a natural abundance of Rb with those containing isotopically pure 87 Rb and 85 Rb. A filter providing > 95 % transmission and Δν ~ 1.1 GHz is achieved.

  14. How to use the cosmological Schwinger principle for energy flux, entropy, and 'atoms of space-time' to create a thermodynamic space-time and multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Beckwith, Andrew, E-mail: beckwith@iibep.org [71 Lakewood court, apt 7, Moriches, New York, 11955 (United States)

    2011-07-08

    We make explicit an idea by Padmanabhan in DICE 2010, as to finding 'atoms of space-time' permitting a thermodynamic treatment of emergent structure similar to Gibbs treatment of statistical physics. That is, an ensemble of gravitons is used to give an 'atom' of space-time congruent with relic GW. The idea is to reduce the number of independent variables to get a simple emergent space-time structure of entropy. An electric field, based upon the cosmological Schwinger principle, is linked to relic heat flux, with entropy production tied in with candidates as to inflaton potentials. The effective electric field links with the Schwinger 1951s result of an E field leading to pairs of e{sup +}e{sup -} charges nucleated in space-time volume V {center_dot} t. Note that in most inflationary models, the assumption is for a magnetic field, not an electric field. An electric field permits a kink-anti-kink construction of an emergent structure, which includes Glinka's recent pioneering approach to a Multiverse. Also an E field allows for an emergent relic particle frequency range between one and 100 GHz. The novel contribution is a relic E field, instead of a B field, in relic space-time 'atom' formation and vacuum nucleation of the same.

  15. Why does the lumen maintenance of sodium-scandium metal halide lamps improve by VHF operation?

    International Nuclear Information System (INIS)

    Van Erk, W; Luijks, G M J F; Hitchcock, W

    2011-01-01

    Lifetime experiments show that sodium-scandium metal halide lamps perform better on very high frequency (VHF) drivers than on low frequency (LF) constant wattage autotransformer (CWA) ballasts. The question why, will be addressed with focus on arc tube aspects. It is argued that at high frequency operation sodium loss is less, and that the absence of thermal fluctuations in the electrode tip causes less damage and cracking to this part of the electrode. Sudden lm W -1 drops, observed with CWA-operated lamps, most probably occur when the arc attaches on such a corroded and cracked surface. Thorium is effective as an emitter both in the CWA and the VHF operation mode, despite the absence of cataphoretic transport to the cathode in the VHF case.

  16. Why does the lumen maintenance of sodium-scandium metal halide lamps improve by VHF operation?

    Energy Technology Data Exchange (ETDEWEB)

    Van Erk, W [Philips Lighting, Sondervick 47, 5505 NB Veldhoven (Netherlands); Luijks, G M J F [Advanced Development Lighting, Philips Lighting, PO Box 80020, 5600 JM Eindhoven (Netherlands); Hitchcock, W, E-mail: Gerard.luijks@philips.com [Philips Lighting Company, 7265 Route 54, Bath, NY 14810 (United States)

    2011-06-08

    Lifetime experiments show that sodium-scandium metal halide lamps perform better on very high frequency (VHF) drivers than on low frequency (LF) constant wattage autotransformer (CWA) ballasts. The question why, will be addressed with focus on arc tube aspects. It is argued that at high frequency operation sodium loss is less, and that the absence of thermal fluctuations in the electrode tip causes less damage and cracking to this part of the electrode. Sudden lm W{sup -1} drops, observed with CWA-operated lamps, most probably occur when the arc attaches on such a corroded and cracked surface. Thorium is effective as an emitter both in the CWA and the VHF operation mode, despite the absence of cataphoretic transport to the cathode in the VHF case.

  17. Influence of scandium on the microstructure and mechanical properties of A319 alloy

    International Nuclear Information System (INIS)

    Emadi, Daryoush; Rao, A.K. Prasada; Mahfoud, Musbah

    2010-01-01

    Recycling of aluminum scrap alloys by melting is gaining its importance in foundry sector. During recycling, some of the alloying elements present in scrap alloys eventually become trace/tramp impurities in the recycled alloy. These elements could potentially affect the alloy's microstructure and hence its mechanical properties. In the present work, an attempt has been made to investigate the effect of one of such trace elements on the microstructure and mechanical properties of A319 alloy. The element chosen for the present investigation is scandium (Sc). This paper discusses the effects of the additions of trace amount of Sc on the microstructure and mechanical properties of A319 alloy in as-cast, T6 and T7 heat treated conditions.

  18. Thermodynamic study of sublimation, melting and vaporization of scandium(III) dipivaloylmethanate derivatives

    International Nuclear Information System (INIS)

    Zherikova, Kseniya V.; Zelenina, Ludmila N.; Chusova, Tamara P.; Gelfond, Nikolay V.; Morozova, Natalia B.

    2016-01-01

    Highlights: • Thermal properties of two volatile fluorinated Sc(III) beta-diketonates were studied. • Saturated and unsaturated vapor pressures were measured. • DSC analysis was carried out. • Sublimation, evaporation and melting enthalpies and entropies were derived. • Effect of fluorine introduction on volatility and thermal stability was established. - Abstract: The present work deals with the investigation of thermal properties of two volatile scandium(III) beta-diketonates with 2,2,6,6-tetramethyl-4-fluoro-3,5-heptanedione and 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione which have been synthesized and purified. Using the static method with glass membrane gauge-manometer the temperature dependencies of saturated and unsaturated vapor pressure were measured for the first time. The temperatures and enthalpies of melting were measured for these compounds by differential scanning calorimetry. The standard thermodynamic characteristics of enthalpy and entropy for sublimation, vaporization and melting processes were derived.

  19. Dielectric matrix, dynamical matrix and phonon dispersion in hcp transition metal scandium

    International Nuclear Information System (INIS)

    Singh, Joginder; Singh, Natthi; Prakash, S.

    1976-01-01

    Complete dielectric matrix is evaluated for hcp transition metal scandium using the non-interacting s- and d-band model. The local field corrections which are consequence of the non-diagonal part of the dielectric matrix are calculated explicitly. The free electron approximation is used for the s-electrons and the simple tight-binding approximation is used for the d-electrons. The theory developed by Singh and others is used to invert the dielectric matrix and the explicit expressions for the dynamical matrix are obtained. The phonon dispersion relations are investigated by using the renormalized Animalu transition metal model potential (TMMP) for bare ion potential. The contribution due to non-central forces which arise due to local fields is found to be 20%. The results are found in resonably good agreement with the experimental values. (author)

  20. Bottom sediment transport study at Haiphong port using radioactive scandium as tracer

    International Nuclear Information System (INIS)

    Pham Ngoc Chuong; Phan Son Hai; Pham Duy Hien

    1993-01-01

    A radioisotope tracer experiment was performed for investigating the bedload movement at the site near the access channel to Haiphong port, North Vietnam. The scandium glass and a number of mechanical devices were manufactured locally for the experiment. Simple and safe procedures were adopted for the production, transportation and injection of radioactive tracer materials. Five tracking experiments were carried out covering the period of 84 days in winter 1992-1993. The experimental results provide a firm basis for elaborating appropriate measures against the siltation problem at Haiphong port, especially for the design of a new access channel with a better orientation with respect to the directions of the water flow and bedload transport, as proposed recently by the Port Authority. (Author). 2 refs, 4 figs

  1. Modification mechanism of eutectic silicon in Al–6Si–0.3Mg alloy with scandium

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [Manufacturing and Systems Engineering Program, Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand); Kajornchaiyakul, Julathep [National Metal and Material Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@kmutt.ac.th [Manufacturing and Systems Engineering Program, Department of Production Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2013-10-25

    Highlights: •Morphologies and growth of Sc and Sr-modified eutectic silicon resemble those of dendrites. •Crystal orientation of eutectic aluminum depends on growth characteristics of eutectic silicon. •We report strong evidence of the occurrence of an impurity-induced twinning mechanism. -- Abstract: The modification mechanism of eutectic silicon in Al–6Si–0.3Mg alloy with scandium was studied. The crystallographic orientation relationships between primary dendrites and the eutectic phase of unmodified and modified Al–6Si–0.3 Mg alloys were determined using electron backscatter diffraction (EBSD). The orientation of aluminum modified with scandium in the eutectic phase was different from that of the neighboring primary dendrites. This result implies that eutectic aluminum grows epitaxially from the surrounding primary aluminum dendrites in the unmodified alloy and that eutectic aluminum grows competitively from the surrounding primary aluminum dendrites in the modified alloy. The pole figure maps of eutectic Si in the [1 0 0], [1 1 0] and [1 1 1] axes of the unmodified and Sc-modified alloys were different, suggesting that the eutectic Al and Si crystals in modified alloy growth are more isotropic and cover a larger set of directions. The lattice fringes of Si of the alloys with and without Sc modification were different in the TEM results. The lattice fringes of Si in modified alloy were found to be multiple twins. However, this was not observed in the unmodified alloy. The growth characteristic of eutectic Si crystal in modified alloy suggests the occurrence of multiple twinning reactions and the formation of a high density of twins. This modification mechanism by Sc is explained by the results of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) analysis, which provide strong evidence of the occurrence of the impurity-induced twinning (IIT) mechanism.

  2. Insights into the mantle geochemistry of scandium from a meta-analysis of garnet data

    Science.gov (United States)

    Chassé, Mathieu; Griffin, William L.; Alard, Olivier; O'Reilly, Suzanne Y.; Calas, Georges

    2018-06-01

    The meta-analysis of about 13,000 analyses of scandium content in garnet grains shows that, below the spinel-garnet transition, this phase carries about three-quarters of the Sc budget of the mantle, indicating its control on Sc mobility. The Sc content of garnets in mafic rocks is low, due to a dilution effect resulting from their high modal content in garnet. Garnets from ultramafic rocks exhibit a wider range of Sc concentrations. We assess the relative influence of thermobarometry, crystal chemistry and fluid-related events on the distribution of Sc in garnet from such rocks to improve the tracking of geochemical processes in the mantle. Pressure and temperature of equilibration in the mantle are second-order factors influencing the Sc content of garnet, while crystal chemistry, in particular Cr/Cr+Al and Ca/Ca+Mg, is the main parameter controlling the compatibility of Sc. Scandium is incorporated in both X and Y sites of Cr-Ca-rich garnets, resulting in a behaviour intermediate between rare-earth elements, incorporated in the X site, and trivalent transition elements, occupying the Y site. This affinity for both sites results in a mild compatibility of Sc in the garnet stability field of the mantle; hence Sc concentration in garnet increases with melt extraction and can be reduced by silicate-melt metasomatism. In contrast, metasomatism by volatile-rich fluids increases the Sc concentration in garnet. The control of garnet on the compatibility of Sc in deep lithospheric rocks demonstrates the potential of using Sc to track the conditions of formation of magmas and their residual rocks, as well as the origin and nature of metasomatic fluids.

  3. Multiscale Study of Hydrogen Adsorption on Six Designed Covalent Organic Frameworks Based on Porphyrazine, Cyclobutane and Scandium

    International Nuclear Information System (INIS)

    Li Le-Le; Gao Teng-Fei; Zhang Ruan-Yu; Zhang Hong

    2014-01-01

    The first-principles method of hydrogen adsorption is used to investigate the interaction of H_2 with the scandium-porphyrazine (Sc-Pz) and porphyrazine (Pz) clusters. The result shows that the interaction of H_2 with Sc-Pz is stronger than with Pz. Then grand canonical Monte Carlo simulations are used to investigate hydrogen adsorption in six designed covalent organic frameworks (COFs), which are designed based on porphyrazine, cyclobutane and scandium. When the pressure is from 0.1 to 100 bar and the temperature is 298 K and 77 K, the hydrogen adsorption capacities of the six COFs are calculated. We further study the importance of Sc and fillers to improve the H_2 uptake in the modified COFs by analyzing the isosteric heat of hydrogen adsorption. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  4. Scandium interaction with diantipyrylmethane homologues and 2-(n-sulphophenylazo)-1,8-dihydroxynaphthalene-3,6 sodium disulphonate

    Energy Technology Data Exchange (ETDEWEB)

    Ganago, L I; Alinovskaya, L A [AN Belorusskoj SSR, Minsk. Inst. Fiziki Tverdogo Tela i Poluprovodnikov

    1979-01-01

    The reactions of scandium with homologs of diantipyrilmethane (DAM)-propyldiantipyrilmethane (PDAM) and phenyldiantipyrilmethane (PhDAM) - are studied. The relationship of components in the complexes formed is found, and chemism of their formation is established. The complexes Sc-SPADNE (sodium salt 2-(n-sulphophenylazo)-1,8-dioxynaphthalene-3,6-disulphonic acid) are shown to form within a wide pH range. The maximum yield of complexes is observed at 6.0-7.5 pH. By the ion-exchange method the anion character of heteroligand scandium complexes is established. The complex Sc-SPADNE-PDAM is faster as compared with the complexes Sc-SPADNE-DAM and Sc-SPADNE-PhDAM. The decrease in amine excess and increase in the sensitivity of heteroligand formation of the complexes of scandium with SPADNE and PDAM make them better suited for analysis. The technique is developed for the determination of Sc/sub 2/O/sub 3/ in perovskites using the complete differential spectrophotometry method.

  5. The effect of scandium addition on microstructure and mechanical properties of Al–Si–Mg alloy: A multi-refinement modifier

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Cong, E-mail: xucong55555@gmail.com [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Xiao, Wenlong, E-mail: wlxiao@buaa.edu.cn [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Hanada, Shuji [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamagata, Hiroshi [Center for Advanced Die Engineering and Technology, Gifu University, 1-1 Yanagido, Gifu City, Gifu 501-1193 (Japan); Ma, Chaoli [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China)

    2015-12-15

    Effect of scandium (Sc) additions on the microstructure, mechanical properties and fracture behavior of Al–Si–Mg casting alloy (F357) were systematically investigated. It was found that Sc addition caused a multi-refining efficiency on the microstructure of as-cast F357 alloy, including refinement of grains and secondary dendrite arm spacing (SDAS), modification of eutectic Si and harmless disposal of β-Al{sub 5}FeSi phase. Subsequent T6 heat treatment had further induced the complete spheroidization of eutectic Si and precipitation of fine secondary Al{sub 3}Sc dispersoids in the Sc modified alloys. Thus the mechanical properties, especially the ductility, were significantly enhanced by the addition of Sc combined with the heat treatment. The highest ultimate tensile strength, yield strength and elongation were achieved in 0.8 wt.% Sc modified F357 alloy combined with T6 heat treatment. Furthermore, fractographic examinations indicated that the ductile fracture mechanism served as a dominate role in the modified alloys due to the formation of fine, deep and uniformly distributed dimples. - Highlights: • Detailed characterization of the multi-refining microstructure of Sc modified F357 alloy was performed. • The multi-refinement was proposed to refine grain and SDAS, modify eutectic Si and β-phase. • Sc modifier combined with T6 treatment is effective in improving tensile properties. • Modification of eutectic Si in F357 alloy with Sc is consistent with the IIT mechanism.

  6. Atomic interferometry

    International Nuclear Information System (INIS)

    Baudon, J.; Robert, J.

    2004-01-01

    Since the theoretical works of L. De Broglie (1924) and the famous experiment of Davisson and Germer (1927), we know that a wave is linked with any particle of mass m by the relation λ = h/(mv), where λ is the wavelength, v the particle velocity and h is the Planck constant. The basic principle of the interferometry of any material particle, atom, molecule or aggregate is simple: using a simple incident wave, several mutually consistent waves (with well-defined relative phases) are generated and controllable phase-shifts are introduced between them in order to generate a wave which is the sum of the previous waves. An interference figure is obtained which consists in a succession of dark and bright fringes. The atomic interferometry is based on the same principle but involves different techniques, different wave equations, but also different beams, sources and correlations which are described in this book. Because of the small possible wavelengths and the wide range of possible atomic interactions, atomic interferometers can be used in many domains from the sub-micron lithography to the construction of sensors like: inertial sensors, gravity-meters, accelerometers, gyro-meters etc. The first chapter is a preliminary study of the space and time diffraction of atoms. The next chapters is devoted to the description of slit, light separation and polarization interferometers, and the last chapter treats of the properties of Bose-Einstein condensates which are interesting in atomic interferometry. (J.S.)

  7. Phenomenological theory of the dielectric response of lead magnesium niobate and lead scandium tantalate

    International Nuclear Information System (INIS)

    Qian, H.; Bursill, L.A.

    1997-01-01

    The influence of the random field effects originating from charges chemical defects and non-domain textures of the formation and dynamics of polar clusters is analyzed. The spatial distribution of the local fields is not totally random but contains some correlations in direction and strength. Polar clusters are classified to be dynamic or frozen according to their dynamic characteristics in the random fields. The relaxation formula of a dipolar moment in an anisotropic double-well potential is deduced. Two percolation models are introduced, one to account for frustration effects associated with multiple orientations of polar clusters, which results in a broad diffuse dielectric response and the second to account for the case whereby there may be a phase transition to a ferroelectric state. The dielectric permittivity and dissipation factor of the typical relaxors lead magnesium niobate and lead scandium tantalate are predicted as a function of both temperature and frequency, which results are in good agreement with the experimental measurements. 30 refs., 9 figs

  8. Microstructure and age-hardening effects of aluminium alloys with additions of scandium and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Galun, R.; Mordike, B.L. [Inst. fuer Werkstoffkunde und Werkstofftechnik, Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany); Maiwald, T.; Smola, B. [Zentrum fuer Funktionswerkstoffe GmbH, Clausthal-Zellerfeld (Germany); Mergen, R.; Manner, M.; Uitz, W. [Miba Gleitlager GmbH, Laakirchen (Australia)

    2004-12-01

    The aim of the work presented in this report was to produce age-hardenable aluminium alloys containing scandium and zirconium by a casting process with similar cooling conditions like an industrial casting process. Microstructure, precipitation structure and age-hardening response of different alloys with up to 0.4 wt.% Sc and Zr were investigated. Age-hardening experiments from the as-cast condition without solution annealing showed a significant increase of hardness of about 100% for Sc-rich alloys and of 50% for Zr-rich alloys compared to the as-cast condition. TEM investigations revealed the formation of precipitates of ternary Al{sub 3}(Sc{sub x}Zr{sub 1-x}) phases with a cubic cP4 crystal structure. In addition to the strengthening effect, a high thermal stability especially of the precipitates in Zr-rich alloys up to 400 C let these alloys look very promising for high-temperature applications. (orig.)

  9. Partitioning of Iron and Scandium in Soils Having Water Drainage Limitations

    International Nuclear Information System (INIS)

    Aide, M.; Braden, I.; Mueller, W.

    2010-01-01

    Soil chemistry of Fe includes weathering reactions, adsorption, hydrolysis, complexation, and oxidation-reduction reactions. Soil chemistry for scandium (Sc) is similar, but Sc does not include oxidation-reduction reactions. To determine if geochemical analysis may be used to identify Sc partitioning with respect to Fe among the particle size fractions, two Alfisol and two Ultisol soils were assessed using an aqua-regia digestion to estimate Sc and Fe concentrations for whole soil and particle size separates. Aqua-regia digestion data showed Sc depletion relative to Fe in sand separate. Sand separate is largely composed on quartz sand and Fe-Mn-bearing nodules, which are redoximorphic features produced by alternating oxic and suboxic/anoxic conditions associated with seasonally fluctuating water tables. Relative partitioning of Fe and Sc in these soils warrants further study to assess if selective extractions could quantify the extent of modern or ancestral oxidation-reduction processes responsible in some soil features involved in soil genesis.

  10. Effect of Aqueous Media on the Recovery of Scandium by Selective Precipitation

    Directory of Open Access Journals (Sweden)

    Bengi Yagmurlu

    2018-05-01

    Full Text Available This research presents a novel precipitation method for scandium (Sc concentrate refining from bauxite residue leachates and the effect of aqueous media on this triple-stage successive precipitation process. The precipitation pattern and the precipitation behavior of the constituent elements was investigated using different precipitation agents in three major mineral acid media, namely, H2SO4, HNO3, and HCl in a comparative manner. Experimental investigations showed behavioral similarities between HNO3 and HCl media, while H2SO4 media was different from them because of the nature of the formed complexes. NH4OH was found to be the best precipitation agent in every leaching media to remove Fe(III with low Sc co-precipitation. To limit Sc loss from the system, Fe(III removal was divided into two steps, leading to more than 90% of Fe(III removal at the end of the process. Phosphate concentrates were produced in the final step of the precipitation process with dibasic phosphates which have a strong affinity towards Sc. Concentrates containing more than 50% of ScPO4 were produced in each case from the solutions after Fe(III removal, as described. A flow diagram of the selective precipitation process is proposed for these three mineral acid media with their characteristic parameters.

  11. Adsorption of hydrogen in Scandium/Titanium decorated nitrogen doped carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Mananghaya, Michael, E-mail: mikemananghaya@gmail.com [De La Salle University, 2401 Taft Ave, 0922, Manila (Philippines); DLSU STC Laguna Boulevard, LTI Spine Road Barangays Biñan and Malamig, Biñan City, Laguna (Philippines); DOST-ASTHRDP, PCIEERD, Gen. Santos Ave., Bicutan, Taguig City 1631 (Philippines); Belo, Lawrence Phoa; Beltran, Arnel [De La Salle University, 2401 Taft Ave, 0922, Manila (Philippines); DLSU STC Laguna Boulevard, LTI Spine Road Barangays Biñan and Malamig, Biñan City, Laguna (Philippines)

    2016-09-01

    Nitrogen doped Carbon Nanotube with divacancy (4ND-CN{sub x}NT) that is decorated with Scandium and Titanium as potential hydrogen storage medium using the pseudo potential density functional method was investigated. Highly localized states near the Fermi level, which are derived from the nitrogen defects, contribute to strong Sc and Ti bindings, which prevent metal aggregation and improve the material stability. A detailed Comparison of the Hydrogen adsorption capability with promising system-weight efficiency of Sc over Ti was elucidated when functionalized with 4ND-CN{sub x}NT. Finally, the (Sc/4ND){sub 10}-CN{sub x}CNT composite material has a thermodynamically favorable adsorption and consecutive adsorption energy for ideal reversible adsorption and desorption of hydrogen at room temperature such that it can hold at least 5.8 wt% hydrogen molecules at the LDA and GGA level. - Highlights: • Carbon Nanotube with divacancy (4ND-CN{sub x}NT) decorated with Sc and Ti. • Nitrogen defects, contribute to strong Sc and Ti bindings. • H{sub 2} and (Sc/4ND){sub 10}-CN{sub x}CNT has a favorable adsorption. • 5.8 wt% adsorption at the LDA and GGA level.

  12. Atomic-Oxygen-Durable and Electrically-Conductive CNT-POSS-Polyimide Flexible Films for Space Applications.

    Science.gov (United States)

    Atar, Nurit; Grossman, Eitan; Gouzman, Irina; Bolker, Asaf; Murray, Vanessa J; Marshall, Brooks C; Qian, Min; Minton, Timothy K; Hanein, Yael

    2015-06-10

    In low Earth orbit (LEO), hazards such as atomic oxygen (AO) or electrostatic discharge (ESD) degrade polymeric materials, specifically, the extensively used polyimide (PI) Kapton. We prepared PI-based nanocomposite films that show both AO durability and ESD protection by incorporating polyhedral oligomeric silsesquioxane (POSS) and carbon nanotube (CNT) additives. The unique methods that are reported prevent CNT agglomeration and degradation of the CNT properties that are common in dispersion-based processes. The influence of the POSS content on the electrical, mechanical, and thermo-optical properties of the CNT-POSS-PI films was investigated and compared to those of control PI and CNT-PI films. CNT-POSS-PI films with 5 and 15 wt % POSS content exhibited sheet resistivities as low as 200 Ω/□, and these resistivities remained essentially unchanged after exposure to AO with a fluence of ∼2.3 × 10(20) O atoms cm(-2). CNT-POSS-PI films with 15 wt % POSS content exhibited an erosion yield of 4.8 × 10(-25) cm(3) O atom(-1) under 2.3 × 10(20) O atoms cm(-2) AO fluence, roughly one order of magnitude lower than that of pure PI films. The durability of the conductivity of the composite films was demonstrated by rolling film samples with a tight radius up to 300 times. The stability of the films to thermal cycling and ionizing radiation was also demonstrated. These properties make the prepared CNT-POSS-PI films with 15 wt % POSS content excellent candidates for applications where AO durability and electrical conductivity are required for flexible and thermally stable materials. Hence, they are suggested here for LEO applications such as the outer layers of spacecraft thermal blankets.

  13. Influence of scandium on the microstructure and strength properties of the welded joint at the laser welding of aluminum-lithium alloys

    Science.gov (United States)

    Malikov, A. G.; Golyshev, A. A.; Ivanova, M. Yu.

    2017-10-01

    Today, aeronautical equipment manufacture involves up-to-date high-strength aluminum alloys of decreased density resulting from lithium admixture. Various technologies of fusible welding of these alloys are being developed. Serious demands are imposed to the welded joints of aluminum alloys in respect to their strength characteristics. The paper presents experimental investigations of the optimization of the laser welding of aluminum alloys with the scandium-modified welded joint. The effect of scandium on the micro-and macro-structure has been studied as well as the strength characteristics of the welded joint. It has been found that scandium under in the laser welding process increases the welded joint elasticity for the system Al-Mg-Li, aluminum alloy 1420 by 20 %, and almost doubles the same for the system Al-Cu-Li, aluminum alloy 1441.

  14. Laboratory studies into the use of the scandium-46-EDTA complex as a tracer for groundwater flow

    International Nuclear Information System (INIS)

    Cheng, H.; Nixon, S.C.

    1988-01-01

    Gamma ray emitting metal radionuclides, when complexed with an appropriate complexing agent, provide a wide choice of water tracers particularly for groundwater studies where a radionuclide of appropriate half-life suited to the particular study can be selected. Scandium-46 has easily detectable gamma emission and a suitable half-life (84 days) for medium term studies. It has been widely and successfully used as a tracer in studies of sediment movement but has not yet been introduced as a groundwater tracer. In our experiments the chemical aspects of the preparation of Sc-46-EDTA were studied in some detail and its behaviour in various mineralogical environments was evaluated with reference to the standard tracer, tritiated water. The experimental results have shown that the scandium cation can be easily complexed with EDTA to form soluble SC-EDTA. The complex is very stable in a wide range of pH; the adsorptive properties of Sc-EDTA in the batch studies and the retardation and recovery in the column tests in comparison with tritiated water are quite satisfactory. In general Sc-46-EDTA is a promising tracer for groundwater studies. In the report the appropriate conditions, procedures and some rational and efficient methods for testing the purity of Sc-46-EDTA in the preparation of the tracer solution of Sc-46-EDTA are described. In addition, it has been found that the formation of the metal hydroxide colloids is the major reason for the great loss in groundwater aquifers of most trivalent metal nuclide tracers in the cationic form including scandium-46. (author). 29 refs, 11 figs, 12 tabs

  15. Complexometric determination of aluminium and scandium using fluorides as masking agent at low pH value

    International Nuclear Information System (INIS)

    Tikhonov, V.N.

    1978-01-01

    A complexometric method is suggested to determine Al and Sc by back titration of Bi(NO 3 ) 3 solution with xylenol orange indicator at low pH values. To increase selectivity fluoride additions were used which were masked by boron acid at the end titration point. EDTA was used as a complexing agent. Metals which create at low pH values stable complexes with EDTA undestroyed by fluoride, do not interfere with Al and Sc determination. Scandium is shown to be determined more selectively than aluminium

  16. Magnetic susceptibility of scandium-hydrogen and lutetium-hydrogen solid-solution alloys from 2 to 3000K

    International Nuclear Information System (INIS)

    Stierman, R.J.

    1982-12-01

    Results for pure Sc show that the maximum and minimum in the susceptibility discovered earlier are enhanced as the impurity level of iron in scandium decreases. The Stoner enhancement factor, calculated from low-temperature heat capacity data, susceptibility data, and band-structure calculations show Sc to be a strongly enhanced paramagnet. Below 2 0 K, the magnetic anisotropy between the hard and easy directions of scandium decreases linearly with decreasing temperature, tending toward zero at 0 K. The large increase in the susceptibility of Sc at lower temperatures indicates magnetic ordering. Pure Lu and Lu-H alloys showed an anisotropy in susceptibility vs orientation; thus the samples were not random polycrystalline samples. Pure Lu shows the shallow maximum and minimum, but the increase in susceptibility at low temperatures is larger than previously observed. The susceptibility-composition dependence of the Lu-H alloys also did not match other data. The susceptibility-composition dependence does not match the composition dependence of the electronic specific heat constant below 150 K, showing the electronic specific heat is being affected by terms other than phonon-electron and pure electron-electron interactions

  17. Atomic Interferometry, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Vertical cavity surface emitting lasers (VCSELs) is a new technology which can be used for developing high performance laser components for atom-based sensors...

  18. Atomic Ferris wheel beams

    Science.gov (United States)

    Lembessis, Vasileios E.

    2017-07-01

    We study the generation of atom vortex beams in the case where a Bose-Einstein condensate, released from a trap and moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.

  19. Self-Assembled Nanocomposite Organic Polymers with Aluminum and Scandium as Heterogeneous Water-Compatible Lewis Acid Catalysts.

    Science.gov (United States)

    Miyamura, Hiroyuki; Sonoyama, Arisa; Hayrapetyan, Davit; Kobayashi, Shū

    2015-09-01

    While water-compatible Lewis acids have great potential as accessible and environmentally benign catalysts for various organic transformations, efficient immobilization of such Lewis acids while keeping high activity and without leaching of metals even under aqueous conditions is a challenging task. Self-assembled nanocomposite catalysts of organic polymers, carbon black, aluminum reductants, and scandium salts as heterogeneous water-compatible Lewis acid catalysts are described. These catalysts could be successfully applied to various C-C bond-forming reactions without leaching of metals. Scanning transmission electron microscopy analyses revealed that the nanocomposite structure of Al and Sc was fabricated in these heterogeneous catalysts. It is noted that Al species, which are usually decomposed rapidly in the presence of water, are stabilized under aqueous conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Scandium doping brings speed improvement in Sb2Te alloy for phase change random access memory application.

    Science.gov (United States)

    Chen, Xin; Zheng, Yonghui; Zhu, Min; Ren, Kun; Wang, Yong; Li, Tao; Liu, Guangyu; Guo, Tianqi; Wu, Lei; Liu, Xianqiang; Cheng, Yan; Song, Zhitang

    2018-05-01

    Phase change random access memory (PCRAM) has gained much attention as a candidate for nonvolatile memory application. To develop PCRAM materials with better properties, especially to draw closer to dynamic random access memory (DRAM), the key challenge is to research new high-speed phase change materials. Here, Scandium (Sc) has been found it is helpful to get high-speed and good stability after doping in Sb 2 Te alloy. Sc 0.1 Sb 2 Te based PCRAM cell can achieve reversible switching by applying even 6 ns voltage pulse experimentally. And, Sc doping not only promotes amorphous stability but also improves the endurance ability comparing with pure Sb 2 Te alloy. Moreover, according to DFT calculations, strong Sc-Te bonds lead to the rigidity of Sc centered octahedrons, which may act as crystallization precursors in recrystallization process to boost the set speed.

  1. Random-field Potts model for the polar domains of lead magnesium niobate and lead scandium tantalate

    Energy Technology Data Exchange (ETDEWEB)

    Qian, H.; Bursill, L.A

    1997-06-01

    A random filed Potts model is used to establish the spatial relationship between the nanoscale distribution of charges chemical defects and nanoscale polar domains for the perovskite-based relaxor materials lead magnesium niobate (PMN) and lead scandium tantalate (PST). The random fields are not set stochastically but are determined initially by the distribution of B-site cations (Mg, Nb) or (Sc, Ta) generated by Monte Carlo NNNI-model simulations for the chemical defects. An appropriate random field Potts model is derived and algorithms developed for a 2D lattice. It is shown that the local fields are strongly correlated with the chemical domain walls and that polar domains as a function of decreasing temperature is simulated for the two cases of PMN and PST. The dynamics of the polar clusters is also discussed. 33 refs., 9 figs.

  2. Modification of radiation sensitivity by salts of the metals beryllium and indium and the rare earths cerium, lanthanum and scandium

    International Nuclear Information System (INIS)

    Floersheim, G.L.

    1995-01-01

    The LD 50 of 46 salts of metals and rare earths (lanthanoids) was determined in mice. Half the LD 50 of the compounds was then combined with lethal radiation (10.5 Gy) and the modification of survival time was scored. Only the metals beryllium and indium and the rare earths cerium, lanthanum and scandium displayed activity in our assay. There were then tested at a wider range of lower doses and reduced survival time in a dose-dependent fashion. This appears to be compatible with enhancement of radiation sensitivity. The interaction of these metals and rare earths with radiation adds a new facet to their toxicological spectrum and, by enhancing radiation effects, may influence estimates of risk. On the other hand, radiosensitizing properties of the metals may be useful for further development of compounds to be used as adjuncts in specific situations of cancer radiotherapy. 31 refs., 1 fig., 1 tab

  3. Atomic resolution imaging of ferroelectric domains

    International Nuclear Information System (INIS)

    Bursill, L.A.

    1997-01-01

    Electron optical principles involved in obtaining atomic resolution images of ferroelectric domains are reviewed, including the methods available to obtain meaningful interpretation and analysis of the image detail in terms of the atomic structures. Recent work is concerned with establishing the relationship between the essentially static chemical nanodomains and the spatial and temporal fluctuations of the nanoscale polar domains present in the relaxor class of materials, including lead scandium tantalate (PST) and lead magnesium niobate (PMN). Correct interpretation of the images required use of Next Nearest Neighbour Ising model simulations for the chemical domain textures upon which we must superimpose the polar domain textures; an introduction to this work is presented. A thorough analysis of the atomic scale chemical inhomogeneities, based upon the HRTEM results, has lead to an improved formulation of the theory of the dielectric response of PMN and PST, which is capable to predict the observed temperature and frequency dependence. HRTEM may be combined with solid state and statistical physics principles to provide a deeper understanding of structure/property relationships. 15 refs., 6 figs

  4. Real-space and real-time dynamics of CRISPR-Cas9 visualized by high-speed atomic force microscopy.

    Science.gov (United States)

    Shibata, Mikihiro; Nishimasu, Hiroshi; Kodera, Noriyuki; Hirano, Seiichi; Ando, Toshio; Uchihashi, Takayuki; Nureki, Osamu

    2017-11-10

    The CRISPR-associated endonuclease Cas9 binds to a guide RNA and cleaves double-stranded DNA with a sequence complementary to the RNA guide. The Cas9-RNA system has been harnessed for numerous applications, such as genome editing. Here we use high-speed atomic force microscopy (HS-AFM) to visualize the real-space and real-time dynamics of CRISPR-Cas9 in action. HS-AFM movies indicate that, whereas apo-Cas9 adopts unexpected flexible conformations, Cas9-RNA forms a stable bilobed structure and interrogates target sites on the DNA by three-dimensional diffusion. These movies also provide real-time visualization of the Cas9-mediated DNA cleavage process. Notably, the Cas9 HNH nuclease domain fluctuates upon DNA binding, and subsequently adopts an active conformation, where the HNH active site is docked at the cleavage site in the target DNA. Collectively, our HS-AFM data extend our understanding of the action mechanism of CRISPR-Cas9.

  5. Study of strength properties of semi-finished products from economically alloyed high-strength aluminium-scandium alloys for application in automobile transport and shipbuilding

    Science.gov (United States)

    Baranov, Vladimir; Sidelnikov, Sergey; Zenkin, Evgeny; Frolov, Viktor; Voroshilov, Denis; Yakivyuk, Olga; Konstantinov, Igor; Sokolov, Ruslan; Belokonova, Irina

    2018-04-01

    The results of a study on the strength of rolled products from aluminium alloys doped with scandium under various processing conditions of hot and cold rolling are presented. The regularities of metal flow and the level of strength of deformed semi-finished products from aluminum-scandium alloys are established, depending on the total degree of deformation and the various modes of single reduction during rolling. It is shown that when using one heating of a cast billet to obtain high-quality semi-finished products, the temperature during the rolling process should not be lower than 350-370°, and the total degree of deformation does not exceed 50-60%. It was found that the semi-finished products from alloys with a content of scandium in the range 0.11-0.12% in the deformed state had elevated values of ultimate tensile strength and yield strength of the metal, which allows them to be recommended for industrial production of sheet metal products.

  6. Angular momentum coupling in atom-atom collisions

    International Nuclear Information System (INIS)

    Grosser, J.

    1986-01-01

    The coupling between the electronic angular momentum and the rotating atom-atom axis in the initial or the final phase of an atom-atom collision is discussed, making use of the concepts of radial and rotational (Coriolis) coupling between different molecular states. The description is based on a limited number of well-understood approximations, and it allows an illustrative geometric representation of the transition from the body fixed to the space fixed motion of the electrons. (orig.)

  7. Development of methods for the selective separation of scandium, zirconium and tin for radiopharmaceutical applications; Entwicklung von Methoden zur selektiven Trennung von Scandium, Zirkonium und Zinn fuer radiopharmazeutische Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Dirks-Fandrei, Carina

    2014-07-01

    The subject of the present work is the development of fast and highly selective methods for the separation and purification of scandium, zirconium and tin radionuclides from potential target materials for use in nuclear medicine. A number of selected resins (TrisKem International) were first characterized with respect to their extraction behaviour towards a large number of cations. Characterization studies were performed in batch experiments by determination of weight distribution ratios D{sub w} and further the influence of interferences on the uptake of these elements was evaluated. Weight distribution ratios were determined in different acids and acid concentrations with main focus on scandium, tin or zirconium. The interference of macro amounts of Calcium and Ti on the Sc extraction was evaluated as well as the interference of macro amounts of Y on the Zr extraction. Best suited uptake conditions were found for Scandium on DGA were determined to be 2.5 M HNO{sub 3} for Ti-Targets and 0.1 M HNO{sub 3} for Calcium-Targets. Otherwise it is also possible to extract Sc with TRU Resin. High uptakes were obtained at 2.5 M HNO{sub 3} for simulated Ti- and Calcium-targets. Separation methods were developed using elution studies; employed conditions were chosen according to parameters evaluated in the batch-experiment. The developed methods allowed separating Sc very rapidly in high purity very rapidly from Ti- or Calcium-targets. For Zr a separation method based on UTEVA Resin has been developed. Following results of batch experiments simulated Y-target solution were loaded onto a UTEVA resin column from 6 M HNO{sub 3}; the elution of Zr could be performed in 0.01 M oxalic acid. Decontamination factors in the order of 10{sup 4}-10{sup 5} could be obtained applying the developed method; the method thus allowed separating Zr in a high purity. Initial testing of a method for the separation of Sn from Cd targets based on the use of TBP Resin showed that the TBP resin seems

  8. Atom optics

    International Nuclear Information System (INIS)

    Balykin, V. I.; Jhe, W.

    1999-01-01

    Atom optics, in analogy to neutron and electron optics, deals with the realization of as a traditional elements, such as lenes, mirrors, beam splitters and atom interferometers, as well as a new 'dissipative' elements such as a slower and a cooler, which have no analogy in an another types of optics. Atom optics made the development of atom interferometer with high sensitivity for measurement of acceleration and rotational possible. The practical interest in atom optics lies in the opportunities to create atom microprobe with atom-size resolution and minimum damage of investigated objects. (Cho, G. S.)

  9. Atom-by-atom assembly

    International Nuclear Information System (INIS)

    Hla, Saw Wai

    2014-01-01

    Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to ‘see’ individual atoms by means of imaging, but is also a tool that is used to ‘touch’ and ‘take’ the atoms, or to ‘hear’ their movements. Therefore, the STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed. (review article)

  10. Performances evaluation of the PHARAO atomic fountain: participation to the study of the PHARAO space clock; Evaluation des performances de la fontaine atomique PHARAO, participation a l'etude de l'horloge spatiale PHARAO

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, M

    2003-01-01

    The performances of an atomic frequency standard depend drastically on the observation time of the atoms. The interrogation of laser cooled atoms allows to obtain about half a second interaction time in a fountain geometry. This duration could be much more varied in absence of gravity, and would allow a better trade-off between stability and accuracy. The application of this principle is the aim of the PHARAO project, that should attend to the ACES mission planned in 2006 onboard the International Space Station. The first part of this thesis deals with the cold Cs{sup 133} PHARAO fountain. This clock stems from the transformation of a space clock prototype previously tested in microgravity. A detailed evaluation of the whole frequency shifts has been carried out, reaching a 7.7 10{sup -16} accuracy and a 1.7 10{sup -13}{tau}{sup -1/2} short term stability. These values are obtained for 4 10{sup 5} detected atoms, that provides a good stability-accuracy trade-off. This transportable fountain, built at BNM-SYRTE, has been operating at MPQ in Munich (Germany). The collaboration between the 2 laboratories gave a {approx} 10 improvement factor on the measurement accuracy (1.8 10{sup -14}) for the 1S - 2S two photons hydrogen transition. In a second part of this thesis, we present the characterisation of 2 elements of the PHARAO space clock: the construction of a standard extended cavity laser and the test of the phase symmetry between the two interrogating areas of the space cavity. (author)

  11. Separation of thorium ions from wolframite and scandium concentrates using graphene oxide

    Czech Academy of Sciences Publication Activity Database

    Jankovský, O.; Sedmidubský, D.; Šimek, P.; Klimová, K.; Bouša, D.; Boothroyd, C.; Macková, Anna; Sofer, Z.

    2015-01-01

    Roč. 17, č. 38 (2015), s. 25272-25277 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA15-09001S; GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : graphite oxide * reduction * oxygen Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 4.449, year: 2015

  12. Ternary scandium-rich indides Sc{sub 50}T{sub 13}In{sub 3} and Sc{sub 50}Rh{sub 13}In{sub 3}O{sub y} (T = Rh, Ir; y {approx} 8) - synthesis and crystal structure

    Energy Technology Data Exchange (ETDEWEB)

    Zaremba, R.; Poettgen, R. [Inst. fuer Anorganische und Analytische Chemie, Univ. Muenster (Germany)

    2007-12-15

    New intermetallic compounds Sc{sub 50}Rh{sub 13.3}In{sub 2.7} and Sc{sub 50}Ir{sub 13.6}In{sub 2.4} and the suboxides Sc{sub 49.2}Rh{sub 13}In{sub 3.8}O{sub 8.8} and Sc{sub 49.2}Rh{sub 13.7}In{sub 2.8}O{sub 8.0} were synthesized from the elements or with Sc{sub 2}O{sub 3} as an oxygen source, respectively, in sealed tantalum tubes in a water-cooled sample chamber of an induction furnace. They crystallize with a new cubic structure type, space group F m anti 3, a = 1772.5(6) pm, wR2 = 0.032, 1111 F{sup 2} values, 34 variables for Sc{sub 50}Rh{sub 13.3}In{sub 2.7}, a = 1766.5(6) pm, wR2 = 0.041, 745 F{sup 2} values, 34 variables for Sc{sub 50}Ir{sub 13.6}In{sub 2.4}, a = 1764.4(2) pm, wR2 = 0.044, 640 F{sup 2} values, 41 variables for Sc{sub 49.2}Rh{sub 13}In{sub 3.8}O{sub 8.8}, and a = 1761.5(6) pm, wR2 = 0.054, 740 F{sup 2} values, 42 variables for Sc{sub 49.2}Rh{sub 13.7}In{sub 2.8}O{sub 8.0}. The main structural motifs are rhodium-centered indium cubes in an fcc like arrangement in which the octahedral and tetrahedral voids are filled by In2Sc{sub 12} and In1Sc{sub 12} icosahedra, respectively, resembling a Li{sub 3}Bi-like structure. The Rh1 (Ir1) and Sc4 atoms lie between these polyhedral units. The oxygen atoms partially fill Sc{sub 6} octahedra in Sc{sub 49.2}Rh{sub 13}In{sub 3.8}O{sub 8.8} and Sc{sub 49.2}Rh{sub 13.7}In{sub 2.8}O{sub 8.0} with Sc-O distances of 214 - 230 pm. These octahedra are condensed via common edges and faces, encapsulating the In2Sc{sub 12} icosahedra. Due to the high scandium content one observes strong Sc-Sc bonding with Sc-Sc distances ranging from 303 to 362 pm in Sc{sub 49.2}Rh{sub 13}In{sub 3.8}O{sub 8.8}. The shortest distances occur for Sc-Rh (267 - 295 pm). The crystal chemical relationship with the Li{sub 3}Bi-related suboxide Ti{sub 12}Sn{sub 3}O{sub 10} is discussed. (orig.)

  13. A beautiful piece of "watch" in Tiangong-2: space atomic clock%天宫二号里那块优雅的“手表”——空间冷原子钟

    Institute of Scientific and Technical Information of China (English)

    乔勇军; 刘伍明

    2017-01-01

    天宫二号带着一款别致的“手表”——空间冷原子钟正在绕着地球翱翔.它仰望深空,俯视大地,探索浩淼宇宙遵循的黄金规则,细致描绘地球母亲的每一寸土地.这是人类史上首台在空间实验室开展科学研究的空间冷原子钟,它的精准度也是史无前例的,为3 000万年误差不超过1s.这台原子钟是中国科学家们历经十数年孕育和抚养成才的,它承载着中国在空间定位、深空探测,以及广义相对论的验证等方面的研究使命.%The space atomic clock,a beautiful piece of "watch" in Tiangong two,looks up at the deep space,overlooks the earth,explores the vast universe following the golden rule,and gives a detailed description of every inch of the earth mother.It is the first space atomic clock to carry out scientific research of the space laboratory in the world,its precision is also unprecedented with error less than one second in thirty million years.This atomic clock is gestated and developed by Chinese scientists taking a dozen years,which carries our positioning,deep space exploration,verification of general relativity and other research assignments.

  14. Potential for photocatalytic degradation of the potassic diclofenac using scandium and silver modified titanium dioxide thin films; Potencial de degradacao fotocatalitica do diclofenaco potassico utilizando filmes finos de dioxido de titanio modificado com escandio e prata

    Energy Technology Data Exchange (ETDEWEB)

    Ciola, R.A.; Oliveira, C.T.; Lopes, S.A.; Cavalheiro, A.A., E-mail: rafaelciola@hotmail.com [Universidade Estadual de Mato Grosso do Sul (UFMS), Navirai, MS (Brazil). Centro de Pesquisas Tecnologicas em Recursos Naturais

    2011-07-01

    The potential for photocatalytic degradation of the potassic diclofenac drug was investigated using titanium dioxide thin films modified with two modifier types, scandium and silver, both prepared by Sol-Gel method. It was demonstrated by UVVis spectroscopy analysis of the solutions containing the drug, under UV-A light irradiation that the degradation efficiency of the titanium dioxide photocatalyst is dependent of the semiconductor nature and that the scandium accelerates the first step of the degradation when compared to the silver. This result seems to be related to the redox potential of the electron-hole pair, once the scandium modifying sample generates a p type semiconductor that reduces the band gap. The extra holes attract more strongly the chorine ion present in diclofenac and leading to the releasing more easily. However, after the first byproducts degradation the following steps are not facilitated, making the silver modifying more advantageous. (author)

  15. Atomic polarizabilities

    International Nuclear Information System (INIS)

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-01

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed

  16. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  17. Atomic physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  18. Atomic physics

    International Nuclear Information System (INIS)

    Armbruster, P.; Beyer, H.; Bosch, F.; Dohmann, H.D.; Kozhuharov, C.; Liesen, D.; Mann, R.; Mokler, P.H.

    1984-01-01

    The heavy ion accelerator UNILAC is well suited to experiments in the field of atomic physics because, with the aid of high-energy heavy ions atoms can be produced in exotic states - that is, heavy atoms with only a few electrons. Also, in close collisions of heavy ions (atomic number Z 1 ) and heavy target atoms (Z 2 ) short-lived quasi-atomic 'superheavy' systems will be formed - huge 'atoms', where the inner electrons are bound in the field of the combined charge Z 1 + Z 2 , which exceeds by far the charge of the known elements (Z <= 109). Those exotic or transient superheavy atoms delivered from the heavy ion accelerator make it possible to study for the first time in a terrestrial laboratory exotic, but fundamental, processes, which occur only inside stars. Some of the basic research carried out with the UNILAC is discussed. This includes investigation of highly charged heavy atoms with the beam-foil method, the spectroscopy of highly charged slow-recoil ions, atomic collision studies with highly ionised, decelerated ions and investigations of super-heavy quasi-atoms. (U.K.)

  19. Ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Krüger, Peter; Hofferberth, S.; Haller, E.

    2005-01-01

    Miniaturized potentials near the surface of atom chips can be used as flexible and versatile tools for the manipulation of ultracold atoms on a microscale. The full scope of possibilities is only accessible if atom-surface distances can be reduced to microns. We discuss experiments in this regime...

  20. Determination of rare-earth elements, yttrium and scandium in manganese nodules by inductively-coupled argon-plastma emission spectrometry

    Science.gov (United States)

    Fries, T.; Lamothe, P.J.; Pesek, J.J.

    1984-01-01

    A sequential-scanning, inductively-coupled argon plasma emission spectrometer is used for the determination of the rare-earth elements, plus yttrium and scandium, in manganese nodules. Wavelength selection is optimized to minimize spectral interferences from manganese nodule components. Samples are decomposed with mixed acids in a sealed polycarbonate vessel, and elements are quantified without further treatment. Results for U.S. Geological Survey manganese nodule standards A-1 and P-1 had average relative standard deviations of 6.8% and 8.1%, respectively, and results were in good agreement with those obtained by other methods. ?? 1984.

  1. Structural characteristics and physical properties of diortho(pyro)silicate crystals of lanthanides yttrium and scandium grown by the Czochralski technique

    Energy Technology Data Exchange (ETDEWEB)

    Anan' eva, G.V.; Karapetyan, V.E.; Korovkin, A.M.; Merkulyaeva, T.I.; Peschanskaya, I.A.; Savinova, I.P.; Feofilov, P.P. (Gosudarstvennyj Opticheskij Inst., Leningrad (USSR))

    1982-03-01

    Optically uniform monocrystals of diortho (pyro) silicates of lanthanides, yttrium, and scandium were grown by the Czochralski technique. Four structural types of Ln/sub 2/(Si/sub 2/O/sub 7/) crystals were determined by the roentgenographic method. The presence of structural subgroups was also supported by the method of spectroscopic probes. Structural parameters were determined and data on certain physical properties (fusion temperature, density, refractive indices, transparency) of investigated crystals were presented. The generation of induced emission at lambda=1.057 ..mu..m was obtained in La/sub 2/(Si/sub 2/O/sub 7/)-Nd/sup 3 +/ crystal.

  2. Determination of metallic impurities in raw materials for radioisotope production by atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Roca, M.; Alvarez, F.; Capdevila, C.

    1969-01-01

    Atomic absorption spectrometry has been used for the determination of traces of calcium in scandium oxide, copper in zinc, iron in cobalt oxide, manganese In ferric oxide, nickel in copper and zinc in gallium oxide. The influences on the sensitivities arising from the hollow cathode currents, the gas pressures and the acid concentrations have been considered. A study of the interferences from the metallic matrices has also been performed, the interference due to the absorption of the manganese radiation by the atoms of iron being the most outstanding . In order to remove the interfering elements and increase sensitivity, pre-concentration methods have been tested. The addition methods has also been used. (Author) 14 refs

  3. Scandium complexes: physico-chemical study and evaluation of stability in vitro and in vivo for nuclear medicine application

    International Nuclear Information System (INIS)

    Kerdjoudj, Rabha

    2014-01-01

    Among the different isotopes of Scandium that can be used in nuclear medicine may be mentioned the 47 Sc and 44 Sc. The first decays by emitting an electron associated with a 159 keV gamma can thus be used either for radiotherapy or TEMP imaging. The 44 Sc (3.97 h) decays in 94.27% in case by emitting a positron, with a γ photon energy equal to 1.157 MeV. This isotope is then an ideal candidate for applications in PET imaging. Currently, the Cyclotron of high energy and high intensity ARRONAX produce 44 Sc and co-produces the isomeric state the 44m Sc (2.44 d). The 44m Sc has properties (E(γ) = 270 keV, 98.8%), which allows to consider its use as a potential in vivo generator. Previous work had demonstrated that the DOTA ligand is most suitable and stable for Sc. This thesis aims; make in evidence the feasibility of the in vivo 44m / 44 Sc generator. Initially a procedure was optimized and validated for the production of 44m / 44 Sc with a high specific activity and chemical purity. Radiolabeling of DOTA conjugated peptides was then developed and optimized. Theoretical and experimental studies have been performed in order to demonstrate the feasibility of 44m / 44 Sc as a potential in vivo generator. Finally, in vitro stability studies on radiolabeled 44m / 44 Sc complexes were performed, followed by biodistribution studies and PET imaging. (author)

  4. Atomic physics

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 2 3 Po, 2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 2 3 Po level of helium-like krypton

  5. Atomic physics

    CERN Document Server

    Born, Max

    1969-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  6. Early Atomism

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/reso/015/10/0905-0925. Keywords. Atomic theory; Avogadro's hypothesis; atomic weights; periodic table; valence; molecular weights; molecular formula; isomerism. Author Affiliations. S Ramasesha1. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, ...

  7. Atom spectroscopy

    International Nuclear Information System (INIS)

    Kodling, K.

    1981-01-01

    Experiments on atom photoabsorption spectroscopy using synchrotron radiation in the 10-1000 eV range are reviewed. Properties of the necessary synchrotron radiation and the experiment on absorption spectroscopy are briefly described. Comparison with other spectroscopy methods is conducted. Some data on measuring photoabsorption, photoelectron emission and atom mass spectra are presented [ru

  8. Exotic atoms

    International Nuclear Information System (INIS)

    Horvath, D.; Lambrecht, R.M.

    1984-01-01

    This bibliography on exotic atoms covers the years 1939 till 1982. The annual entries are headed by an introduction describing the state of affairs of the branch of science and listing the main applications in quantum electrodynamics, particle physics, nuclear physics, atomic physics, chemical physics and biological sciences. The bibliography includes an author index and a subject index. (Auth.)

  9. Laser Source for Atomic Gravity Wave Detector

    Data.gov (United States)

    National Aeronautics and Space Administration — The Atom Interferometry (AI) Technology for Gravity Wave Measurements demonstrates new matter wave Interferometric sensor technology for precise detection and...

  10. Space space space

    CERN Document Server

    Trembach, Vera

    2014-01-01

    Space is an introduction to the mysteries of the Universe. Included are Task Cards for independent learning, Journal Word Cards for creative writing, and Hands-On Activities for reinforcing skills in Math and Language Arts. Space is a perfect introduction to further research of the Solar System.

  11. Determination of scandium in acid mine drainage by ICP-OES with flow injection on-line preconcentration using oxidized multiwalled carbon nanotubes.

    Science.gov (United States)

    Jerez, Javier; Isaguirre, Andrea C; Bazán, Cristian; Martinez, Luis D; Cerutti, Soledad

    2014-06-01

    An on-line scandium preconcentration and determination system implemented with inductively coupled plasma optical emission spectrometry associated with flow injection was studied. Trace amounts of scandium were preconcentrated by sorption on a minicolumn packed with oxidized multiwalled carbon nanotubes, at pH 1.5. The retained analyte was removed from the minicolumn with 30% (v/v) nitric acid. A total enrichment factor of 225-fold was obtained within a preconcentration time of 300 s (for a 25 mL sample volume). The overall time required for preconcentration and elution of 25 mL of sample was about 6 min; the throughput was about 10 samples per hour. The value of the detection limit was 4 ng L(-1) and the precision for 10 replicate determinations at 100 ng L(-1) Sc level was 5% relative standard deviation, calculated from the peak heights obtained. The calibration graph using the preconcentration system was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 10 mg L(-1). After optimization, the method was successfully applied to the determination of Sc in an acid drainage from an abandoned mine located in the province of San Luis, Argentina. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Effects of scandium and zirconium combination alloying on as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy

    Directory of Open Access Journals (Sweden)

    Xiang Qingchun

    2011-02-01

    Full Text Available The influences of minor scandium and zirconium combination alloying on the as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy have been experimentally investigated. The experimental results show that when the minor elements of scandium and zirconium are simultaneously added into the Al-4Cu-1.5Mg alloy, the as-cast microstructure of the alloy is effectively modified and the grains of the alloy are greatly refined. The coarse dendrites in the microstructure of the alloy without Sc and Zr additions are refined to the uniform and fine equiaxed grains. As the additions of Sc and Zr are 0.4% and 0.2%, respectively, the tensile strength, yield strength and elongation of the alloy are relatively better, which are 275.0 MPa, 176.0 MPa and 8.0% respectively. The tensile strength is increased by 55.3%, and the elongation is nearly raised three times, compared with those of the alloy without Sc and Zr additions.

  13. Synthesis, structures, and electroluminescent properties of scandium N,O-chelated complexes toward near-white organic light-emitting diodes.

    Science.gov (United States)

    Katkova, Marina A; Balashova, Tatyana V; Ilichev, Vasilii A; Konev, Alexey N; Isachenkov, Nikolai A; Fukin, Georgy K; Ketkov, Sergey Yu; Bochkarev, Mikhail N

    2010-06-07

    Three members of a new class of electroluminescent, neutral, and monomeric scandium N,O-chelate complexes, namely, Sc(III)-tris-2-(2-benzoimidazol-2-yl)phenolate (1), Sc(III)-tris-2-(2-benzoxyazol-2-yl)phenolate (2), and Sc(III)-tris-2-(2-benzothiazol-2-yl)phenolate (3), have been prepared and X-ray characterized. DFT calculations have been performed. In contrast to the most frequently applied dual or multiple dopants in multilayer white OLED devices, all our simpler devices with the configuration of indium tin oxide/N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine/neat scandium complex/Yb exhibit close to near-white emission with a blue hue (CIE(x,y) = 0.2147, 0.2379) in the case of 1, a cyan hue (0.2702, 0.3524) in the case of 2, and a yellowish hue (0.3468; 0.4284) in the case of 3.

  14. Atomic fusion, Gerrard atomic fusion

    International Nuclear Information System (INIS)

    Gerrard, T.H.

    1980-01-01

    In the approach to atomic fusion described here the heat produced in a fusion reaction, which is induced in a chamber by the interaction of laser beams and U.H.F. electromagnetic beams with atom streams, is transferred to a heat exchanger for electricity generation by a coolant flowing through a jacket surrounding the chamber. (U.K.)

  15. Interference Pattern Formation between Bounded-Solitons and Radiation in Momentum Space: Possible Detection of Radiation from Bounded-Solitons with Bose-Einstein Condensate of Neutral Atoms

    OpenAIRE

    Fujishima, Hironobu; Okumura, Masahiko; Mine, Makoto; Yajima, Tetsu

    2012-01-01

    We propose an indirect method to observe radiation from an incomplete soliton with sufficiently large amplitude. We show that the radiation causes a notched structure on the envelope of the wave packet in the momentum space. The origin of this structure is a result of interference between the main body of oscillating solitons and the small radiation in the momentum space. We numerically integrate the nonlinear Schr\\"odinger equation and perform Fourier transformation to confirm that the predi...

  16. Superradiators created atom by atom

    Science.gov (United States)

    Meschede, Dieter

    2018-02-01

    High radiation rates are usually associated with macroscopic lasers. Laser radiation is “coherent”—its amplitude and phase are well-defined—but its generation requires energy inputs to overcome loss. Excited atoms spontaneously emit in a random and incoherent fashion, and for N such atoms, the emission rate simply increases as N. However, if these atoms are in close proximity and coherently coupled by a radiation field, this microscopic ensemble acts as a single emitter whose emission rate increases as N2 and becomes “superradiant,” to use Dicke's terminology (1). On page 662 of this issue, Kim et al. (2) show the buildup of coherent light fields through collective emission from atomic radiators injected one by one into a resonator field. There is only one atom ever in the cavity, but the emission is still collective and superradiant. These results suggest another route toward thresholdless lasing.

  17. Modeling of atomization and distribution of drop-liquid fuel in unsteady swirling flows in a combustion chamber and free space

    Science.gov (United States)

    Sviridenkov, A. A.; Toktaliev, P. D.; Tretyakov, V. V.

    2018-03-01

    Numerical and experimental research of atomization and propagation of drop-liquid phase in swirling flow behind the frontal device of combustion chamber was performed. Numerical procedure was based on steady and unsteady Reynolds equations solution. It's shown that better agreement with experimental data could be obtained with unsteady approach. Fractional time step method was implemented to solve Reynolds equations. Models of primary and secondary breakup of liquid fuel jet in swirling flows are formulated and tested. Typical mean sizes of fuel droplets for base operational regime of swirling device and combustion chamber were calculated. Comparison of main features of internal swirling flow in combustion chamber with unbounded swirling flow was made.

  18. The features of the atomic structure of the impurities complexes in the irradiated materials doped by the elements with a large atomic radii

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Sleptsov, A.N.; Marchenko, I.G.; Sleptsov, S.N.

    1995-01-01

    The interaction between impurity atoms and radiation-induced defects in Ni(Sc), Ni(Ti), Ni(Pr) and Ni(Y) alloys irradiated with 5 and 30 MeV electrons were studied by the residual resistivity measurements, and the methods of reciprocal damage rate and positron annihilation. The activation energies of the main recovery stages in pure nickel (I D+E - 54 K, II 4 -250 K, III 2 - 390 K) and dilute alloys (up to 700 K) were determined. The radii trapping, r t , of self-interstitial atoms (SIA) by the Sc and Ti atoms were calculated in the temperature range 45-300 K.It is found that the scandium atoms (among all large atomic size elements) are effective traps for SIA and vacancies and form compound complexes. The binding energy of vacancy-impurity complexes are about 0.25, 0.30 and 0.6 - 0.8 eV in Ni(Ti), Ni(Y) and Ni(Sc) alloys, respectively. The solubilities of Sc, Ti, Y and Pr in nickel were deduced from the analysis of dependence of the specific residual resistivity (ρ t ) and the lattice parameter (Δa/a) on concentration. 38 refs., 3 tab., 10 figs

  19. Electric field imaging of single atoms

    Science.gov (United States)

    Shibata, Naoya; Seki, Takehito; Sánchez-Santolino, Gabriel; Findlay, Scott D.; Kohno, Yuji; Matsumoto, Takao; Ishikawa, Ryo; Ikuhara, Yuichi

    2017-01-01

    In scanning transmission electron microscopy (STEM), single atoms can be imaged by detecting electrons scattered through high angles using post-specimen, annular-type detectors. Recently, it has been shown that the atomic-scale electric field of both the positive atomic nuclei and the surrounding negative electrons within crystalline materials can be probed by atomic-resolution differential phase contrast STEM. Here we demonstrate the real-space imaging of the (projected) atomic electric field distribution inside single Au atoms, using sub-Å spatial resolution STEM combined with a high-speed segmented detector. We directly visualize that the electric field distribution (blurred by the sub-Å size electron probe) drastically changes within the single Au atom in a shape that relates to the spatial variation of total charge density within the atom. Atomic-resolution electric field mapping with single-atom sensitivity enables us to examine their detailed internal and boundary structures. PMID:28555629

  20. Atomic politics

    International Nuclear Information System (INIS)

    Skogmar, G.

    1979-01-01

    The authors basic point is that the military and civil sides of atomic energy cannot be separated. The general aim of the book is to analyze both the military and civil branches, and the interdependence between them, of American foreign policy in the atomic field. Atomic policy is seen as one of the most important imstruments of foreign policy which, in turn, is seen against the background of American imperialism in general. Firstly, the book investigates the most important means by which the United States has controlled the development in the nuclear field in other countries. These means include influencing the conditions of access to nuclear resources of various kinds, influencing the flow of technical-economic information and influencing international organizations and treaties bearing on atomic energy. The time period treated is 1945-1973. 1973 is chosen as the end-year of the study mainly because of the new conditions in the whole energy field initiated by the oil crisis in that year. The sources of the empirical work are mainly hearings before the Joint Committee on Atomic Energy of the U.S. Congress and legal material of various kinds. Secondly, the goals of the American policy are analyzed. The goals identified are armament effect, non-proliferation (horizontal), sales, and energy dependence. The relation between the main goals is discussed.The discussion is centered on the interdependence between the military and the civil aspects, conflict and coincidence of various goals, the relation between short-term and long-term goals, and the possibilities of using one goal as pretext for another. Thirdly, some causes of the changes in the atomic policy around 1953 and 1963 are identified. These are the strategic balance, the competitive situation, the capacity (of the American atomic productive apparatus), and the nuclear technological stage. The specific composition of these four factors at the two time-points can explain the changes of policy. (author)

  1. Atomic secrecy

    International Nuclear Information System (INIS)

    Sweet, W.

    1979-01-01

    An article, The H-Bomb Secret: How We Got It, Why We're Telling It, by Howard Morland was to be published in The Progressive magazine in February, 1979. The government, after learning of the author's and the editors' intention to publish the article and failing to persuade them to voluntarily delete about 20% of the text and all of the diagrams showing how an H-bomb works, requested a court injunction against publication. Acting under the Atomic Energy Act of 1954, US District Court Judge Robert W. Warren granted the government's request on March 26. Events dealing with the case are discussed in this publication. Section 1, Progressive Hydrogen Bomb Case, is discussed under the following: Court Order Blocking Magazine Report; Origins of the Howard Morland Article; Author's Motives, Defense of Publication; and Government Arguments Against Disclosure. Section 2, Access to Atomic Data Since 1939, contains information on need for secrecy during World War II; 1946 Atomic Energy Act and its effects; Soviet A-Bomb and the US H-Bomb; and consequences of 1954 Atomic Energy Act. Section 3, Disputed Need for Atomic Secrecy, contains papers entitled: Lack of Studies on H-Bomb Proliferation; Administration's Position on H-Bombs; and National Security Needs vs Free Press

  2. Physics for all, who want to join in conversation. On atomic power, dirty bombs, space research, solar energy, and the global heating

    International Nuclear Information System (INIS)

    Muller, Richard A.

    2009-01-01

    Which dangers contains the global heating really? What can happen at an attack on a atomic power plant?. Which chances offer renewable energies? Questions which are put daily in the pursuing of news - but to which we have only seldomly answers ready, because basic physical knowledge is absent. But it must not even be the great world policy. Already at the decision wether solar cells shall be mounted on the roof or punted on geothermal heat physics are not unimportant. More often than we think it are natural sciences, which yield the foundations for important decisions. Richard A. Muller explains simply and illustratively, how physics determines our life. Thereby he removes prejudices and mediates quite surprising insights

  3. Atom chip gravimeter

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Ahlers, Holger; Müntinga, Hauke; Matthias, Jonas; Sahelgozin, Maral; Herr, Waldemar; Lämmerzahl, Claus; Ertmer, Wolfgang; Rasel, Ernst

    2016-04-01

    Atom interferometry has developed into a tool for measuring rotations [1], accelerations [2], and testing fundamental physics [3]. Gravimeters based on laser cooled atoms demonstrated residual uncertainties of few microgal [2,4] and were simplified for field applications [5]. Atomic gravimeters rely on the interference of matter waves which are coherently manipulated by laser light fields. The latter can be interpreted as rulers to which the position of the atoms is compared. At three points in time separated by a free evolution, the light fields are pulsed onto the atoms. First, a coherent superposition of two momentum states is produced, then the momentum is inverted, and finally the two trajectories are recombined. Depending on the acceleration the atoms experienced, the number of atoms detected in the output ports will change. Consequently, the acceleration can be determined from the output signal. The laser cooled atoms with microkelvin temperatures used in state-of-the-art gravimeters impose limits on the accuracy [4]. Therefore, ultra-cold atoms generated by Bose-Einstein condensation and delta-kick collimation [6,7] are expected to be the key for further improvements. These sources suffered from a low flux implying an incompatible noise floor, but a competitive performance was demonstrated recently with atom chips [8]. In the compact and robust setup constructed for operation in the drop tower [6] we demonstrated all steps necessary for an atom chip gravimeter with Bose-Einstein condensates in a ground based operation. We will discuss the principle of operation, the current performance, and the perspectives to supersede the state of the art. The authors thank the QUANTUS cooperation for contributions to the drop tower project in the earlier stages. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM

  4. Antimatter atoms

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    In january 1996, CERN broadcasted the information of the creation of nine anti-hydrogen atoms, observed through disintegration products. The experimental facility was CERN LEAR ring. An antiproton beam scattered a xenon jet, and the resulting antimatter was first selected by its insensitivity to beam bending magnets. Their disintegration was detected in thin NaI detectors, in which the anti-atoms are at once deprived from their positron. Then, magnetic and time-of-flight spectrometers are used. (D.L.)

  5. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  6. Atomic Layer Deposition Re Ective Coatings For Future Astronomical Space Telescopes And The Solar Corona Viewed Through The Minxss (Miniature X-Ray Solar Spectrometer) Cubesats

    Science.gov (United States)

    Moore, Christopher Samuel

    2017-11-01

    Advances in technology and instrumentation open new windows for observing astrophysical objects. The first half of my dissertation involves the development of atomic layer deposition (ALD) coatings to create high reflectivity UV mirrors for future satellite astronomical telescopes. Aluminum (Al) has intrinsic reflectance greater than 80% from 90 – 2,000 nm, but develops a native aluminum oxide (Al2O3) layer upon exposure to air that readily absorbs light below 250 nm. Thus, Al based UV mirrors must be protected by a transmissive overcoat. Traditionally, metal-fluoride overcoats such as MgF2 and LiF are used to mitigate oxidation but with caveats. We utilize a new metal fluoride (AlF3) to protect Al mirrors deposited by ALD. ALD allows for precise thickness control, conformal and near stoichiometric thin films. We prove that depositing ultra-thin ( 3 nm) ALD ALF3 to protect Al mirrors after removing the native oxide layer via atomic layer etching (ALE) enhances the reflectance near 90 nm from 5% to 30%.X-ray detector technology with high readout rates are necessary for the relatively bright Sun, particularly during large flares. The hot plasma in the solar corona generates X-rays, which yield information on the physical conditions of the plasma. The second half of my dissertation includes detector testing, characterization and solar science with the Miniature X-ray Solar Spectrometer (MinXSS) CubeSats. The MinXSS CubeSats employ Silicon Drift Diode (SDD) detectors called X123, which generate full sun spectrally resolved ( 0.15 FWHM at 5.9 keV) measurements of the sparsely measured, 0.5 – 12 keV range. The absolute radiometric calibration of the MinXSS instrument suite was performed at the National Institute for Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility (SURF) and spectral resolution determined from radioactive sources. I used MinXSS along with data from the Geostationary Operational Environmental Satellites (GOES), Reuven Ramaty

  7. Atoms stories

    International Nuclear Information System (INIS)

    Radvanyi, P.; Bordry, M.

    1988-01-01

    Physicists from different countries told each evening during one learning week, to an audience of young people, some great discoveries in evoking the difficulties and problems to which the researchers were confronted. From Antiquity to a more recent history, it is a succession of atoms stories. (N.C.)

  8. Atomic physics

    International Nuclear Information System (INIS)

    Held, B.

    1991-01-01

    This general book describes the change from classical physics to quantum physics. The first part presents atom evolution since antiquity and introduces fundamental quantities and elements of relativity. Experiments which have contributed to the evolution of knowledge on matter are analyzed in the second part. Applications of wave mechanics to the study of matter properties are presented in the third part [fr

  9. Zeeman spectrum of scandium

    International Nuclear Information System (INIS)

    Lulu, B.A.

    1980-09-01

    The spectra of Sc I, Sc II, Sc III, and Sc IV are analyzed through the use of the Zeeman effect. A sliding spark of the author's design is used in conjunction with a 27 kilogauss electromagnet. The spectra have (reciprocal) dispersions of 0.2 to 0.5 A/mm. 10 Sc I levels, 16 Sc II levels and 5 Sc III levels show Zeeman splitting. No Sc IV Zeeman patterns were observed. 2 Sc I, 4 Sc II, and all of the Sc III level data are new

  10. Atom-surface potentials and atom interferometry

    International Nuclear Information System (INIS)

    Babb, J.F.

    1998-01-01

    Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)

  11. Three-dimensional atom localization via electromagnetically induced transparency in a three-level atomic system.

    Science.gov (United States)

    Wang, Zhiping; Cao, Dewei; Yu, Benli

    2016-05-01

    We present a new scheme for three-dimensional (3D) atom localization in a three-level atomic system via measuring the absorption of a weak probe field. Owing to the space-dependent atom-field interaction, the position probability distribution of the atom can be directly determined by measuring the probe absorption. It is found that, by properly varying the parameters of the system, the probability of finding the atom in 3D space can be almost 100%. Our scheme opens a promising way to achieve high-precision and high-efficiency 3D atom localization, which provides some potential applications in laser cooling or atom nano-lithography via atom localization.

  12. Exotic atoms

    International Nuclear Information System (INIS)

    Kunselman, R.

    1993-01-01

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation

  13. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  14. Atom Nanooptics Based on Photon Dots and Photon Holes

    OpenAIRE

    Balykin, V. I.; Klimov, V. V.; Letokhov, V. S.

    2003-01-01

    New types of light fields localized in nanometer-sized regions of space were suggested and analyzed. The possibility of using these nanolocalized fields in atom optics for atom focusing and localization is discussed.

  15. Dependency Ordering of Atomic Observables

    Science.gov (United States)

    Cīrulis, Jānis

    2015-12-01

    The notion of atomic observable was introduced by S.Gudder for effect test spaces in 1997. In this paper an observable is a σ-homomorphism from the Borel algebra on a line to some logic. Roughly, an observable on a logic is atomic, if it is completely determined by its restriction to one-element subsets of its point spectrum. In particular, every discrete observable is atomic. We study some elementary properties of such observables, and discuss a possible notion of functional dependency between them. Algebraically, a dependency is a certain preorder relation on the set of all atomic observables, which induces an order relation on the set of all maximal orthogonal subsets of the logic. Several properties, as well as characteristics in terms of the underlying logic, of these relations are stated.

  16. Physics and performances of III-V nanowire broken-gap heterojunction TFETs using an efficient tight-binding mode-space NEGF model enabling million-atom nanowire simulations.

    Science.gov (United States)

    Afzalian, A; Vasen, T; Ramvall, P; Shen, T-M; Wu, J; Passlack, M

    2018-06-27

    We report the capability to simulate in a quantum-mechanical atomistic fashion record-large nanowire devices, featuring several hundred to millions of atoms and a diameter up to 18.2 nm. We have employed a tight-binding mode-space NEGF technique demonstrating by far the fastest (up to 10 000  ×  faster) but accurate (error  <  1%) atomistic simulations to date. Such technique and capability opens new avenues to explore and understand the physics of nanoscale and mesoscopic devices dominated by quantum effects. In particular, our method addresses in an unprecedented way the technologically-relevant case of band-to-band tunneling (BTBT) in III-V nanowire broken-gap heterojunction tunnel-FETs (HTFETs). We demonstrate an accurate match of simulated BTBT currents to experimental measurements in a 12 nm diameter InAs NW and in an InAs/GaSb Esaki tunneling diode. We apply our TB MS simulations and report the first in-depth atomistic study of the scaling potential of III-V GAA nanowire HTFETs including the effect of electron-phonon scattering and discrete dopant impurity band tails, quantifying the benefits of this technology for low-power low-voltage CMOS applications.

  17. Impact of layer and substrate properties on the surface acoustic wave velocity in scandium doped aluminum nitride based SAW devices on sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Gillinger, M., E-mail: manuel.gillinger@tuwien.ac.at; Knobloch, T.; Schneider, M.; Schmid, U. [Institute of Sensor and Actuator Systems, TU Wien, 1040 Vienna (Austria); Shaposhnikov, K.; Kaltenbacher, M. [Institute of Mechanics and Mechatronics, TU Wien, 1040 Vienna (Austria)

    2016-06-06

    This paper investigates the performance of surface acoustic wave (SAW) devices consisting of reactively sputter deposited scandium doped aluminum nitride (Sc{sub x}Al{sub 1-x}N) thin films as piezoelectric layers on sapphire substrates for wireless sensor or for RF-MEMS applications. To investigate the influence of piezoelectric film thickness on the device properties, samples with thickness ranging from 500 nm up to 3000 nm are fabricated. S{sub 21} measurements and simulations demonstrate that the phase velocity is predominantly influenced by the mass density of the electrode material rather than by the thickness of the piezoelectric film. Additionally, the wave propagation direction is varied by rotating the interdigital transducer structures with respect to the crystal orientation of the substrate. The phase velocity is about 2.5% higher for a-direction compared to m-direction of the sapphire substrate, which is in excellent agreement with the difference in the anisotropic Young's modulus of the substrate corresponding to these directions.

  18. Serum sample levels of bromine, iron, scandium and zinc in preschool children of Atayal and Bunun aborigines living in central Taiwan

    International Nuclear Information System (INIS)

    Chien-Yi Chen; Ding-Bang Lin; Yuan-Yaw Wei

    2006-01-01

    This study determined bromine, iron, scandium and zinc serum levels in Taiwanese aboriginal preschool children living in remote mountainous areas to increase the understanding of the social, cultural, nutrient and ethnic background of the Taiwanese children. Seventy-three serum samples were taken from two ethnic groups of preschool children, Atayal aborigines (AAPC) and Bunun aborigines (BAPC). Sera of these children were freeze dried. Trace elements in sera were identified by instrumental neutron activation analysis (INAA). The accuracy and precision of INAA was evaluated using certified reference materials: Tomato Leaves (NIST-SRM 1570a) and Lichen (IAEA-336). Statistical analysis identified several different patterns for ethnic groups, gender and age via the two-tailed Student's t-test. Analytical results showed that the ranges of Br, Fe, Sc and Zn in sera were somewhat wide. The Zn serum levels (p < 0.05) and Br serum levels (p < 0.01) in the AAPC were significantly lower than those in the BAPC. However, there were no significant differences in Fe or Sc serum levels between the two groups. Analytical results were compared to published data for different counties. This study is the first investigating trace elements in Taiwanese aborigines and can be used to establish a much-needed serum element database. (author)

  19. Comparative microstructure and electrical property studies of lead scandium tantalate thin films as prepared by LDCVD, sol-gel and sputtering techniques

    International Nuclear Information System (INIS)

    Huang, Z; Donohue, P P; Zhang, Q; Williams, D J; Anthony, C J; Whatmore, R W; Todd, M A

    2003-01-01

    Lead scandium tantalate (PST) thin films for uncooled infrared (IR) detector applications have been deposited by liquid delivery chemical vapour deposition (LDCVD), sputtering and sol-gel techniques. The sol-gel and sputtered films were deposited at low temperature into a non-ferroelectric phase with the required perovskite structure being formed using a high temperature rapid thermal anneal (RTA). In contrast to this, the LDCVD films were deposited at high temperature directly into the perovskite phase but were found to still require a high temperature RTA step to optimize their merit for IR detection. Detailed structural and electrical characterization of the PST films deposited by these different methods have revealed that there is no simple relationship between microstructure and electrical properties. The sol-gel and LDCVD techniques produce thin films with excellent microstructures, as determined by x-ray diffraction analysis and transmission electron microscopy, but inferior electrical properties and relatively low merit figures. By contrast, the sputtered and then rapid thermal annealed films have inferior microstructures, characterized by extensive voiding, but excellent electrical properties and high merit figures

  20. Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications.

    Science.gov (United States)

    Verma, Mahesh; Kumari, Pooja; Gupta, Rekha; Gill, Shubhra; Gupta, Ankur

    2015-01-01

    Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique. Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3-0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine. The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer. Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength. Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

  1. Aluminum-Scandium Alloys: Material Characterization, Friction Stir Welding, and Compatibility With Hydrogen Peroxide (MSFC Center Director's Discretionary Fund Final Report, Proj. No. 04-14)

    Science.gov (United States)

    Lee, J. A.; Chen, P. S.

    2004-01-01

    This Technical Memorandum describes the development of several high-strength aluminum (Al) alloys that are compatible with hydrogen peroxide (H2O2) propellant for NASA Hypersonic-X (Hyper-X) vehicles fuel tanks and structures. The yield strengths for some of these Al-magnesium-based alloys are more than 3 times stronger than the conventional 5254-H112 Al alloy, while maintaining excellent H2O2 compatibility similar to class 1 5254 alloy. The alloy development strategy is to add scandium, zirconium, and other transitional metals with unique electrochemical properties, which will not act as catalysts, to decompose the highly concentrated 90 percent H2O2. Test coupons are machined from sheet metals for H2O2 long-term exposure testing and mechanical properties testing. In addition, the ability to weld the new alloys using friction stir welding has also been explored. The new high-strength alloys could represent an enabling material technology for Hyper-X vehicles, where flight weight reduction is a critical requirement.

  2. Investigation of concentration-dependence of thermodynamic properties of lanthanum, yttrium, scandium and terbium in eutectic LiCl-KCl molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo, E-mail: zhang.3558@osu.edu

    2016-09-15

    Thermodynamic properties of rare earth metals in LiCl-KCl molten salt electrolyte are crucial to the development of electrochemical separation for the treatment of used nuclear fuels. In the present study, activity coefficient, apparent potential, and diffusion coefficient of lanthanum, yttrium, scandium, and terbium in the molten salt (58 at% LiCl and 42 at% KCl) were calculated by the method of molecular dynamics simulation up to a concentration around 3 at% at temperatures of 723 K and 773 K. It was found that the activity coefficient and the apparent potential increase with the species concentration while diffusion coefficient shows a trend of increase followed by decrease. The calculated results were validated by available measurement data of dilution cases. This research extends the range of data to a wide component and would provide further insight to the pyroprocessing design and safeguards. - Highlights: • Investigation of activity coefficient, apparent potential and diffusion coefficient at different concentrations. • MD simulation was studied for the calculation of thermodynamic properties of rare earth elements in molten salt. • The present study is a pioneering work focusing on the concentration dependence of thermodynamic properties.

  3. Atomic reactor thermal engineering

    International Nuclear Information System (INIS)

    Kim, Gwang Ryong

    1983-02-01

    This book starts the introduction of atomic reactor thermal engineering including atomic reaction, chemical reaction, nuclear reaction neutron energy and soon. It explains heat transfer, heat production in the atomic reactor, heat transfer of fuel element in atomic reactor, heat transfer and flow of cooler, thermal design of atomic reactor, design of thermodynamics of atomic reactor and various. This deals with the basic knowledge of thermal engineering for atomic reactor.

  4. Atomic energy

    International Nuclear Information System (INIS)

    Ramanna, R.

    1978-01-01

    Development of nuclear science in India, particularly the research and development work at the Bhabha Atomic Research Centre (BARC), Bombay, is described. Among the wide range of materials developed for specific functions under rigorous conditions are nuclear pure grade uranium, zirconium and beryllium, and conventional materials like aluminium, carbon steel and stainless steels. Radioisotopes are produced and used for tracer studies in various fields. Various types of nuclear gauges and nuclear instruments are produced. Radiations have been used to develop new high yielding groundnut mutants with large kernals. The sterile male technique for pest control and radiosterilization technique to process potatoes, onions and marine foods for storage are ready for exploitation. Processes and equipment have been developed for production of electrolytic hydrogen, electrothermal phosphorus and desalinated water. Indigenously manufactured components and materials are now being used for the nuclear energy programme. Indian nuclear power programme strategy is to build heavy water reactors and to utilise their byproduct plutonium and depleted uranium to feed fast breeder reactors which will produce more fissile material than burnt. Finally a special mention has been made of the manpower development programme of the BARC. BARC has established a training school in 1957 giving advanced training in physics, chemistry and various branches of engineering and metallurgy

  5. Laser Source for Atomic Gravity Wave Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Atom Interferometry (AI) Technology for Gravity Wave Measurements demonstrates new matter wave Interferometric sensor technology for precise detection and...

  6. Bremsstrahlung in atom-atom collisions

    International Nuclear Information System (INIS)

    Amus'ya, M.Y.; Kuchiev, M.Y.; Solov'ev, A.V.

    1985-01-01

    It is shown that in the collision of a fast atom with a target atom when the frequencies are on the order of the potentials or higher, there arises bremsstrahlung comparable in intensity with the bremsstrahlung emitted by an electron with the same velocity in the field of the target atom. The mechanism by which bremsstrahlung is produced in atom-atom collisions is elucidated. Results of specific calculations of the bremsstrahlung spectra are given for α particles and helium atoms colliding with xenon

  7. Atomic weights of the elements 2013 (IUPAC Technical Report)

    Science.gov (United States)

    Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna; Loss, Robert D.; Walczyk, Thomas; Prohaska, Thomas

    2016-01-01

    The biennial review of atomic-weight determinations and other cognate data has resulted in changes for the standard atomic weights of 19 elements. The standard atomic weights of four elements have been revised based on recent determinations of isotopic abundances in natural terrestrial materials:cadmium to 112.414(4) from 112.411(8),molybdenum to 95.95(1) from 95.96(2),selenium to 78.971(8) from 78.96(3), andthorium to 232.0377(4) from 232.038 06(2). The Commission on Isotopic Abundances and Atomic Weights (ciaaw.org) also revised the standard atomic weights of fifteen elements based on the 2012 Atomic Mass Evaluation:aluminium (aluminum) to 26.981 5385(7) from 26.981 5386(8),arsenic to 74.921 595(6) from 74.921 60(2),beryllium to 9.012 1831(5) from 9.012 182(3),caesium (cesium) to 132.905 451 96(6) from 132.905 4519(2),cobalt to 58.933 194(4) from 58.933 195(5),fluorine to 18.998 403 163(6) from 18.998 4032(5),gold to 196.966 569(5) from 196.966 569(4),holmium to 164.930 33(2) from 164.930 32(2),manganese to 54.938 044(3) from 54.938 045(5),niobium to 92.906 37(2) from 92.906 38(2),phosphorus to 30.973 761 998(5) from 30.973 762(2),praseodymium to 140.907 66(2) from 140.907 65(2),scandium to 44.955 908(5) from 44.955 912(6),thulium to 168.934 22(2) from 168.934 21(2), andyttrium to 88.905 84(2) from 88.905 85(2). The Commission also recommends the standard value for the natural terrestrial uranium isotope ratio, N(238U)/N(235U)=137.8(1).

  8. Reflection-type hologram for atoms

    International Nuclear Information System (INIS)

    Shimizu, Fujio; Fujita, Jun-ichi

    2002-01-01

    A cold metastable neon atomic beam was manipulated with a reflective amplitude hologram that was encoded on a silicon surface. A black-and-white pattern of atoms was reconstructed on a microchannel plate detector. The hologram used the enhanced quantum reflection developed by authors and was made of a two-dimensional array of rectangular low and high reflective cells. The surface of the high reflective cell was composed of regularly spaced roof-shaped ridges, while the low reflective cell was simply a flat surface. The hologram was the first demonstration of reflective atom-optical elements that used universal interaction between a neutral atom and solid surface

  9. Atomic weight versus atomic mass controversy

    International Nuclear Information System (INIS)

    Holden, N.E.

    1985-01-01

    A problem for the Atomic Weights Commission for the past decade has been the controversial battle over the names ''atomic weight'' and ''atomic mass''. The Commission has considered the arguments on both sides over the years and it appears that this meeting will see more of the same discussion taking place. In this paper, I review the situation and offer some alternatives

  10. Photonic and Quantum Interactions of Atomic-Scale Junctions

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, the fundamental quantum and photonic interactions of bimetallic atomic-scale junctions (ASJs) will be explored, with three major space...

  11. Highly excited atoms

    International Nuclear Information System (INIS)

    Kleppner, D.; Littman, M.G.; Zimmerman, M.L.

    1981-01-01

    Highly excited atoms are often called Rydberg atoms. These atoms have a wealth of exotic properties which are discussed. Of special interest, are the effects of electric and magnetic fields on Rydberg atoms. Ordinary atoms are scarcely affected by an applied electric or magnetic field; Rydberg atoms can be strongly distorted and even pulled apart by a relatively weak electric field, and they can be squeezed into unexpected shapes by a magnetic field. Studies of the structure of Rydberg atoms in electric and magnetic fields have revealed dramatic atomic phenomena that had not been observed before

  12. Laser-assisted atom-atom collisions

    International Nuclear Information System (INIS)

    Roussel, F.

    1984-01-01

    The basic layer-assisted atom-atom collision processes are reviewed in order to get a simpler picture of the main physical facts. The processes can be separated into two groups: optical collisions where only one atom is changing state during the collision, the other acting as a spectator atom, and radiative collisions where the states of the two atoms are changing during the collision. All the processes can be interpreted in terms of photoexcitation of the quasimolecule formed during the collisional process. (author)

  13. Space polypropulsion

    CSIR Research Space (South Africa)

    Kellett, BJ

    2008-04-01

    Full Text Available understandably, fallen by the wayside. NASAs putative atom bomb propelled mission, coincidently also baptized ORION, was also curtailed. And last of all, the use of lasers for propulsion remains firmly “stuck in the doldrums.” This mode of access to space...) Except for LOX, very polluting. V. high ζ Launch costs: $20,000/kg. Gas guns. 1 1-4 km/s Most of the system mass stays on the ground. Recoil problems. Large NASA gas gun project abandoned. (too many “g’s”) E-M guns: rail/coil. 1.5 1-10 km...

  14. Code ATOM for calculation of atomic characteristics

    International Nuclear Information System (INIS)

    Vainshtein, L.A.

    1990-01-01

    In applying atomic physics to problems of plasma diagnostics, it is necessary to determine some atomic characteristics, including energies and transition probabilities, for very many atoms and ions. Development of general codes for calculation of many types of atomic characteristics has been based on general but comparatively simple approximate methods. The program ATOM represents an attempt at effective use of such a general code. This report gives a brief description of the methods used, and the possibilities of and limitations to the code are discussed. Characteristics of the following processes can be calculated by ATOM: radiative transitions between discrete levels, radiative ionization and recombination, collisional excitation and ionization by electron impact, collisional excitation and ionization by point heavy particle (Born approximation only), dielectronic recombination, and autoionization. ATOM explores Born (for z=1) or Coulomb-Born (for z>1) approximations. In both cases exchange and normalization can be included. (N.K.)

  15. On new ternary equiatomic scandium transition metal aluminum compounds ScTAl with T = Cr, Ru, Ag, Re, Pt, and Au

    Energy Technology Data Exchange (ETDEWEB)

    Radzieowski, Mathis; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Benndorf, Christopher [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Haverkamp, Sandra [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; University of Sao Paulo, Sao Carlos, SP (Brazil). Inst. of Physics

    2016-08-01

    The new equiatomic scandium transition metal aluminides ScTAl for T = Cr, Ru, Ag, Re, Pt, and Au were obtained by arc-melting of the elements followed by subsequent annealing for crystal growth. The samples were studied by powder and single crystal X-ray diffraction. The structures of three compounds were refined from single crystal X-ray diffractometer data: ScCrAl, MgZn{sub 2} type, P6{sub 3}/mmc, a = 525.77(3), c = 858.68(5) pm, R{sub 1} = 0.0188, wR{sub 2} = 0.0485, 204 F{sup 2} values, 13 variables, ScPtAl, TiNiSi type, Pnma, a = 642.83(4), b = 428.96(2), c = 754.54(5) pm, R{sub 1} = 0.0326, wR{sub 2} = 0.0458, 448 F{sup 2} values, 20 variables and ScAuAl, HfRhSn type, P anti 62c, a = 722.88(4), c = 724.15(4) pm, R{sub 1} = 0.0316, wR{sub 2} = 0.0653, 512 F{sup 2} values, 18 variables. Phase pure samples of all compounds were furthermore investigated by magnetic susceptibility measurements, and Pauli-paramagnetism but no superconductivity was observed down to 2.1 K for all of them. The local structural features and disordering phenomena have been characterized by {sup 27}Al and {sup 45}Sc magic angle spinning (MAS) and static NMR spectroscopic investigations.

  16. Comparative study of the shear bond strength of composite resin bonded to enamel treated with acid etchant and erbium, chromium: Yttrium, scandium, gallium, garnet laser

    Directory of Open Access Journals (Sweden)

    Adel Sulaiman Alagl

    2016-01-01

    Full Text Available Aim: The purpose of this investigation is in vitro comparison of the shear bond strength (SBS of composite resin bonded to enamel pretreated with an acid etchant against enamel etched with erbium, chromium: yttrium, scandium, gallium, garnet (Er, Cr:YSGG laser. Materials and Methods: Sixty premolars were sectioned mesiodistally and these 120 specimens were separated into two groups of 60 each (Groups A and B. In Group A (buccal surfaces, enamel surface was etched using 37% phosphoric acid for 15 s. In Group B (lingual surfaces, enamel was laser-etched at 2W for 10 s by Er, Cr:YSGG laser operational at 2780 nm with pulse duration of 140 μs and a frequency of 20 Hz. After application of bonding agent on all test samples, a transparent plastic cylinder of 1.5 mm × 3 mm was loaded with composite and bonded by light curing for 20 s. All the samples were subjected to SBS analysis using Instron Universal testing machine. Failure modes were observed under light microscope and grouped as adhesive, cohesive, and mixed. Failure mode distributions were compared using the Chi-square test. Results: SBS values obtained for acid-etched enamel were in the range of 7.12–28.36 megapascals (MPa and for laser-etched enamel were in the range of 6.23–23.35 MPa. Mean SBS for acid-etched enamel was 15.77 ± 4.38 MPa, which was considerably greater (P < 0.01 than laser-etched enamel 11.24 ± 3.76 MPa. The Chi-square test revealed that the groups showed no statistically significant differences in bond failure modes. Conclusions: We concluded that the mean SBS of composite with acid etching is significantly higher as compared to Er, Cr: YSGG (operated at 2W for 10 s laser-etched enamel.

  17. Universal Four-Boson System: Dimer-Atom-Atom Efimov Effect and Recombination Reactions

    International Nuclear Information System (INIS)

    Deltuva, A.

    2013-01-01

    Recent theoretical developments in the four-boson system with resonant interactions are described. Momentum-space scattering equations for the four-particle transition operators are used. The properties of unstable tetramers with approximate dimer-atom-atom structure are determined. In addition, the three- and four-cluster recombination processes in the four-boson system are studied. (author)

  18. 'Seeing' Atoms: The Crystallographic Revolution.

    Science.gov (United States)

    Schwarzenbach, Dieter

    2014-02-26

    Laue's experiment in 1912 of the diffraction of X-rays by crystals led to one of the most influential discoveries in the history of science: the first determinations of crystal structures, NaCl and diamond in particular, by W. L. Bragg in 1913. For the first time, the visualisation of the structure of matter at the atomic level became possible. X-ray diffraction provided a sort of microscope with atomic resolution, atoms became observable physical objects and their relative positions in space could be seen. All branches of science concerned with matter, solid-state physics, chemistry, materials science, mineralogy and biology, could now be firmly anchored on the spatial arrangement of atoms. During the ensuing 100 years, structure determination by diffraction methods has matured into an indispensable method of chemical analysis. We trace the history of the development of 'small-structure' crystallography (excepting macromolecular structures) in Switzerland. Among the pioneers figure Peter Debye and Paul Scherrer with powder diffraction, and Paul Niggli and his Zurich School with space group symmetry and geometrical crystallography. Diffraction methods were applied early on by chemists at the Universities of Bern and Geneva. By the 1970s, X-ray crystallography was firmly established at most Swiss Universities, directed by full professors. Today, chemical analysis by structure determination is the task of service laboratories. However, the demand of diffraction methods to solve problems in all disciplines of science is still increasing and powerful radiation sources and detectors are being developed in Switzerland and worldwide.

  19. High-dimensional atom localization via spontaneously generated coherence in a microwave-driven atomic system.

    Science.gov (United States)

    Wang, Zhiping; Chen, Jinyu; Yu, Benli

    2017-02-20

    We investigate the two-dimensional (2D) and three-dimensional (3D) atom localization behaviors via spontaneously generated coherence in a microwave-driven four-level atomic system. Owing to the space-dependent atom-field interaction, it is found that the detecting probability and precision of 2D and 3D atom localization behaviors can be significantly improved via adjusting the system parameters, the phase, amplitude, and initial population distribution. Interestingly, the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. Our scheme opens a promising way to achieve high-precision and high-efficiency atom localization, which provides some potential applications in high-dimensional atom nanolithography.

  20. Quantum information entropies of ultracold atomic gases in a ...

    Indian Academy of Sciences (India)

    The position and momentum space information entropies of weakly interacting trapped atomic Bose–Einstein condensates and spin-polarized trapped atomic Fermi gases at absolute zero temperature are evaluated. We find that sum of the position and momentum space information entropies of these quantum systems ...

  1. Ionization of H Rydberg atoms

    International Nuclear Information System (INIS)

    Hillermier, C.F.; Bluemental, R.; Smilansky, U.

    1991-07-01

    Concepts from the theory of transient chaos are applied to study the classical ionization process of one dimensional model of kicked hydrogen Rydberg atoms. The phase-space dynamics is represented by a mapping T which is proved to be hyperbolic. The fraction of atoms not ionized after time t, P B (t), decays asymptotically according to P B (t)∼t -α with α ∼ 1.65. The observed algebraic decay, which seems to contradict the hyperbolicity of T, is explained by (i) the symbolic dynamics of T consists of a countably infinite number of symbols and (ii) the invariant manifold of phase-space points which never ionize is an anomalously scaling fractal. Therefore, the one-dimensional kicked hydrogen atom provides a counterexample to the hypothesis that algebraic decay marks regular dynamics, whereas hyperbolic systems decay exponentially. The algebraic decay is reproduced by an analytically solvable diffusion model which predicts α = 3/2. Replacing zero-width δ-kicks by smooth finite-width pulses, the mapping T is no longer completely hyperbolic, and a subset of phase-space is regular. For this case we observe that P B (t) shows a transition between two power-law decays with α ∼ 1.65 for short times and α ∼ 2.1 for long times where the effect of the regular domain is felt. (author)

  2. Determination of metallic impurities in raw materials for radioisotope production by atomic absorption spectroscopy; Determinacion de trazas metalicas en amterias primas para la produccion de radioisotopos por espectroscopia de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M; Alvarez, F; Capdevila, C

    1969-07-01

    Atomic absorption spectrometry has been used for the determination of traces of calcium in scandium oxide, copper in zinc, iron in cobalt oxide, manganese In ferric oxide, nickel in copper and zinc in gallium oxide. The influences on the sensitivities arising from the hollow cathode currents, the gas pressures and the acid concentrations have been considered. A study of the interferences from the metallic matrices has also been performed, the interference due to the absorption of the manganese radiation by the atoms of iron being the most outstanding . In order to remove the interfering elements and increase sensitivity, pre-concentration methods have been tested. The addition methods has also been used. (Author) 14 refs.

  3. Atomic fountain and applications

    International Nuclear Information System (INIS)

    Rawat, H.S.

    2000-01-01

    An overview of the development of working of MOT along with the basic principle of laser atom cooling and trapping is given. A technique to separate the cooled and trapped atoms from the MOT using atomic fountain technique will also be covered. The widely used technique for atomic fountain is, first to cool and trap the neutral atoms in MOT and then launch them in the vertical direction, using moving molasses technique. Using 133 Cs atomic fountain clock, time improvement of 2 to 3 order of magnitude over a conventional 133 Cs atomic clock has been observed

  4. Interferometry with atoms

    International Nuclear Information System (INIS)

    Helmcke, J.; Riehle, F.; Witte, A.; Kisters, T.

    1992-01-01

    Physics and experimental results of atom interferometry are reviewed and several realizations of atom interferometers are summarized. As a typical example of an atom interferometer utilizing the internal degrees of freedom of the atom, we discuss the separated field excitation of a calcium atomic beam using four traveling laser fields and demonstrate the Sagnac effect in a rotating interferometer. The sensitivity of this interferometer can be largely increased by use of slow atoms with narrow velocity distribution. We therefore furthermore report on the preparation of a laser cooled and deflected calcium atomic beam. (orig.)

  5. Three-atom clusters

    International Nuclear Information System (INIS)

    Pen'kov, F.M.

    1998-01-01

    The Born-Oppenheimer approximation is used to obtain an equation for the effective interaction in three atoms bound by a single electron. For low binding energies in an 'electron + atom' pair, long-range forces arise between the atoms, leading to bound states when the size of the three-atom cluster is a few tens of angstrom. A system made of alkali-metal atoms is considered as an example

  6. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    Niinikoski, T.O.; Penttilae, S.; Rieubland, J.M.; Rijllart, A.

    1984-01-01

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  7. Solvent extraction of anionic chelate complexes of lanthanum(III), europium(III), lutetium(III), scandium(III), and indium(III) with 2-thenoyltrifluoroacetone as ion-pairs with tetrabutylammonium ions

    International Nuclear Information System (INIS)

    Noro, Junji; Sekine, Tatsuya.

    1992-01-01

    The solvent extraction of lanthanum(III), europium(III), lutetium(III), scandium(III), and indium(III) in 0.1 mol dm -3 sodium nitrate solutions with 2-thenoyltrifluoroacetone (Htta) in the absence and presence of tetrabutylammonium ions (tba + ) into carbon tetrachloride was measured. The extraction of lanthanum(III), europium(III), and lutetium(III) was greatly enhanced by the addition of tba + ; this could be explained in terms of the extraction of a ternary complex, M(tta) 4 - tba + . However, the extractions of scandium(III) and indium(III) were nearly the same when tba + was added. The data were treated on the basis of the formation equilibrium of the ternary complex from the neutral chelate, M(tta) 3 , with the extracted ion-pairs of the reagents, tta - tba + , in the organic phase. It was concluded that the degree of association of M(tta) 3 with the ion-pair, tta - tba + , is greater in the order La(tta) 3 ≅ Eu(tta) 3 > Lu(tta) 3 , or that the stability of the ternary complex in the organic phase is higher in the order La(tta) 4 - tba + ≅ Eu(tta) 4 - tba + > Lu(tta) 4 - tba + . This is similar to those of adduct metal chelates of Htta with tributylphosphate (TBP) in synergistic extraction systems. (author)

  8. Graphene for Expandable Space Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Graphene's tightly bonded impermeable single atomic layer of carbon offers unrivalled potential for lightweight flexible gas barrier applications. Graphene has been...

  9. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  10. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  11. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  12. Progress in atomic spectroscopy

    International Nuclear Information System (INIS)

    Beyer, H.J.; Kleinpoppen, H.

    1984-01-01

    This book presents reviews by leading experts in the field covering areas of research at the forefront of atomic spectroscopy. Topics considered include the k ordering of atomic structure, multiconfiguration Hartree-Fock calculations for complex atoms, new methods in high-resolution laser spectroscopy, resonance ionization spectroscopy (inert atom detection), trapped ion spectroscopy, high-magnetic-field atomic physics, the effects of magnetic and electric fields on highly excited atoms, x rays from superheavy collision systems, recoil ion spectroscopy with heavy ions, investigations of superheavy quasi-atoms via spectroscopy of electron rays and positrons, impact ionization by fast projectiles, and amplitudes and state parameters from ion- and atom-atom excitation processes

  13. 3D atom microscopy in the presence of Doppler shift

    Science.gov (United States)

    Rahmatullah; Chuang, You-Lin; Lee, Ray-Kuang; Qamar, Sajid

    2018-03-01

    The interaction of hot atoms with laser fields produces a Doppler shift, which can severely affect the precise spatial measurement of an atom. We suggest an experimentally realizable scheme to address this issue in the three-dimensional position measurement of a single atom in vapors of rubidium atoms. A three-level Λ-type atom-field configuration is considered where a moving atom interacts with three orthogonal standing-wave laser fields and spatial information of the atom in 3D space is obtained via an upper-level population using a weak probe laser field. The atom moves with velocity v along the probe laser field, and due to the Doppler broadening the precision of the spatial information deteriorates significantly. It is found that via a microwave field, precision in the position measurement of a single hot rubidium atom can be attained, overcoming the limitation posed by the Doppler shift.

  14. Atomic Fisher information versus atomic number

    International Nuclear Information System (INIS)

    Nagy, A.; Sen, K.D.

    2006-01-01

    It is shown that the Thomas-Fermi Fisher information is negative. A slightly more sophisticated model proposed by Gaspar provides a qualitatively correct expression for the Fisher information: Gaspar's Fisher information is proportional to the two-third power of the atomic number. Accurate numerical calculations show an almost linear dependence on the atomic number

  15. Phase separation in Al-Zr-Sc alloys: from atomic jumps to ordered precipitates growth; Separation de phase dans les alliages Al-Zr-Sc: du saut des atomes a la croissance de precipites ordonnes

    Energy Technology Data Exchange (ETDEWEB)

    Clouet, E

    2004-07-01

    Zirconium and scandium addition to aluminium alloys leads to the formation of ordered precipitates. This study aims to a better understanding of precipitation kinetics thanks to an approach combining atomic and mesoscopic models. An experimental work has been undertaken too so as to characterize by transmission electron microscopy Al{sub 3}Zr kinetics of precipitation. We mainly focus on the nucleation stage and, in this purpose, an atomic model lying on a rigid lattice has been built for Al-Zr-Sc system allowing us to study precipitation with kinetic Monte Carlo simulations. While keeping the vacancy exchange mechanism for diffusion, we introduce multi-site interactions going thus beyond a simple pair interaction model, and test the influence of these interactions on kinetics of precipitation. The comparison between Monte Carlo simulations and classical nucleation theory shows that mesoscopic models can lead to a good description of the nucleation stage of Al{sub 3}Zr and Al{sub 3}Sc as long as the order tendency of the system has been taken into account to calculate input parameters of these models. For the ternary Al-Zr-Sc system, atomic simulations allow a better understanding of the precipitation kinetic path. It is then possible to extend the field of classical nucleation theory so as to model nucleation in a ternary alloy where the stoichiometry of the precipitates is unknown. (author)

  16. Atomic-fluorescence spectrophotometry

    International Nuclear Information System (INIS)

    Bakhturova, N.F.; Yudelevich, I.G.

    1975-01-01

    Atomic-fluorescence spectrophotometry, a comparatively new method for the analysis of trace quantities, has developed rapidly in the past ten years. Theoretical and experimental studies by many workers have shown that atomic-fluorescence spectrophotometry (AFS) is capable of achieving a better limit than atomic absorption for a large number of elements. The present review examines briefly the principles of atomic-fluorescence spectrophotometry and the types of fluorescent transition. The excitation sources, flame and nonflame atomizers, used in AFS are described. The limits of detection achieved up to the present, using flame and nonflame methods of atomization are given

  17. Quantum chaos in atom optics

    International Nuclear Information System (INIS)

    D'Arcy, Michael Brendan

    2002-01-01

    technique for measuring gravity, and a method of preparing atoms in a particular region of phase space. This may allow measurement of quantum phase space stability, and hence investigation of quantum chaos and quantum-classical correspondence. (author)

  18. Effect of temperature on atom-atom collision chain length in metals

    International Nuclear Information System (INIS)

    Makarov, A.A.; Demkin, N.A.; Lyashchenko, B.G.

    1981-01-01

    Focused atom-atom collision chain lengths are calculated for fcc-crystals with account of thermal oscillations. The model of solid spheres with the Born-Merier potential has been used in the calculations. The dependence of chain lengths on the temperature, energy and movement direction of the first chain atom for Cu, Au, Ag, Pb, Ni is considered. The plot presented shows that the chain lengths strongly decrease with temperature growth, for example, for the gold at T=100 K the chain length equals up to 37 interatomic spacings, whereas at T=1000 K their length decreases down to 5 interatomic distances. The dependence of the energy loss by the chain atoms on the atom number in the chain is obtained in a wide range of crystal temperature and the primary chain atom energy [ru

  19. A Single Atom Antenna

    International Nuclear Information System (INIS)

    Trinter, Florian; Williams, Joshua B; Weller, Miriam; Waitz, Markus; Pitzer, Martin; Voigtsberger, Jörg; Schober, Carl; Kastirke, Gregor; Müller, Christian; Goihl, Christoph; Burzynski, Phillip; Wiegandt, Florian; Wallauer, Robert; Kalinin, Anton; Schmidt, Lothar Ph H; Schöffler, Markus S; Jahnke, Till; Dörner, Reinhard; Chiang, Ying-Chih; Gokhberg, Kirill

    2015-01-01

    Here we demonstrate the smallest possible implementation of an antenna-receiver complex which consists of a single (helium) atom acting as the antenna and a second (neon) atom acting as a receiver. (paper)

  20. Atom Wavelike Nature Solved Mathematically

    Science.gov (United States)

    Sven, Charles

    2010-03-01

    Like N/S poles of a magnet the strong force field surrounding, confining the nucleus exerts an equal force [noted by this author] driving electrons away from the attraction of positively charged protons force fields in nucleus -- the mechanics for wavelike nature of electron. Powerful forces corral closely packed protons within atomic nucleus with a force that is at least a million times stronger than proton's electrical attraction that binds electrons. This then accounts for the ease of electron manipulation in that electron is already pushed away by the very strong atomic N/S force field; allowing electrons to drive photons when I strike a match. Ageless atom's electron requirements, used to drive light/photons or atom bomb, without batteries, must be supplied from a huge, external, super high frequency, super-cooled source, undetected by current technology, one that could exist 14+ billion years without degradation -- filling a limitless space prior to Big Bang. Using only replicable physics, I show how our Universe emanated from that event.

  1. Atom chips: mesoscopic physics with cold atoms

    International Nuclear Information System (INIS)

    Krueger, P.; Wildermuth, S.; Hofferberth, S.; Haller, E.; GAllego Garcia, D.; Schmiedmayer, J.

    2005-01-01

    Full text: Cold neutral atoms can be controlled and manipulated in microscopic potentials near surfaces of atom chips. These integrated micro-devices combine the known techniques of atom optics with the capabilities of well established micro- and nanofabrication technology. In analogy to electronic microchips and integrated fiber optics, the concept of atom chips is suitable to explore the domain of mesoscopic physics with matter waves. We use current and charge carrying structures to form complex potentials with high spatial resolution only microns from the surface. In particular, atoms can be confined to an essentially one-dimensional motion. In this talk, we will give an overview of our experiments studying the manipulation of both thermal atoms and BECs on atom chips. First experiments in the quasi one-dimensional regime will be presented. These experiments profit from strongly reduced residual disorder potentials caused by imperfections of the chip fabrication with respect to previously published experiments. This is due to our purely lithographic fabrication technique that proves to be advantageous over electroplating. We have used one dimensionally confined BECs as an ultra-sensitive probe to characterize these potentials. These smooth potentials allow us to explore various aspects of the physics of degenerate quantum gases in low dimensions. (author)

  2. Quasi-atoms

    International Nuclear Information System (INIS)

    Armbruster, P.

    1976-01-01

    The concept of a quasi-atom is discussed, and several experiments are described in which molecular or quasi-atomic transitions have been observed. X-ray spectra are shown for these experiments in which heavy ion projectiles were incident on various targets and the resultant combined system behaved as a quasi-atom. This rapidly developing field has already given new insight into atomic collision phenomena. (P.J.S.)

  3. Gravitational perturbations of the hydrogen atom

    International Nuclear Information System (INIS)

    Parker, L.

    1983-01-01

    The strength of a gravitational field is characterized by the Riemann curvature tensor. It is of interest to know how the curvature of space-time at the position of an atom affects its spectrum. The author gives a brief summary of work on the effects of curvature on the hydrogen atom. The results refer to an arbitrary metric and can be evaluated for particular space-times of interest. The possibility of using the effect of gravitational waves on the electromagnetic spectrum of hydrogen as a means of detecting gravitational waves is also investigated. (Auth.)

  4. Atomic Energy Control Act

    International Nuclear Information System (INIS)

    1970-01-01

    This act provides for the establishment of the Atomic Energy Control Board. The board is responsible for the control and supervision of the development, application and use of atomic energy. The board is also considered necessary to enable Canada to participate effectively in measures of international control of atomic energy

  5. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  6. Measurement of fluorescence emission spectrum of few strongly driven atoms using an optical nanofiber.

    Science.gov (United States)

    Das, Manoj; Shirasaki, A; Nayak, K P; Morinaga, M; Le Kien, Fam; Hakuta, K

    2010-08-02

    We show that the fluorescence emission spectrum of few atoms can be measured by using an optical nanofiber combined with the optical heterodyne and photon correlation spectroscopy. The observed fluorescence spectrum of the atoms near the nanofiber shows negligible effects of the atom-surface interaction and agrees well with the Mollow triplet spectrum of free-space atoms at high excitation intensity.

  7. Atom-atom collision cascades localization

    International Nuclear Information System (INIS)

    Kirsanov, V.V.

    1980-01-01

    The presence of an impurity and thermal vibration influence on the atom-atom collision cascade development is analysed by the computer simulation method (the modificated dynamic model). It is discovered that the relatively low energetic cascades are localized with the temperature increase of an irradiated crystal. On the basis of the given effect the mechanism of splitting of the high energetic cascades into subcascades is proposed. It accounts for two factors: the primary knocked atom energy and the irradiated crystal temperature. Introduction of an impurity also localizes the cascades independently from the impurity atom mass. The cascades localization leads to intensification of the process of annealing in the cascades and reduction of the post-cascade vacancy cluster sizes. (author)

  8. A miniature magnetic waveguide for cold atoms

    International Nuclear Information System (INIS)

    Key, M.G.

    2000-09-01

    This thesis presents the first demonstration of a guide for cold atoms based on a miniature structure of four current-carrying wires. The four wires are embedded within a hollow silica fibre. Atoms are guided along the centre of a fifth hole on the axis of the fibre by the Stern-Gerlach force. A vapour cell Magneto Optical Trap (MOT), formed 1 cm above the mouth of the waveguide is the source of cold 85 Rb atoms. After cooling the atoms to 25 μK in optical molasses they fall under the influence of gravity through a magnetic funnel into the waveguide. After propagating for 2 cm, the atoms are reflected by the field of a small pinch coil wound around the base of the guide. The atoms then travel back up the fibre and out into the funnel, where they can be imaged either in fluorescence or by recapturing in the MOT. A video sequence of atoms falling into the guide and re-emerging after reflection from the pinch coil graphically illustrates the operation of the guide. The coupling efficiency and transverse temperature of the atoms is measured experimentally and in a Monte-Carlo simulation. We find an optimum coupling efficiency of 12% and we measure the spatial extent of the cloud within the fibre to be of order 100 μm. We find good agreement between experimental data and results from the numerical simulation. We have also been able to observe different thresholds for the reflection of different positive m F levels. In another experiment we are able to trap the atoms in an elongated Ioffe trap for up to two seconds, increasing the distance over which the atoms are guided. We are able to guide the atoms over distances of 40 cm with a loss rate indistinguishable from the free space loss rate. (author)

  9. Magnetic conveyor belt for transporting and merging trapped atom clouds.

    Science.gov (United States)

    Hänsel, W; Reichel, J; Hommelhoff, P; Hänsch, T W

    2001-01-22

    We demonstrate an integrated magnetic device which transports cold atoms near a surface with very high positioning accuracy. Time-dependent currents in a lithographic conductor pattern create a moving chain of potential wells; atoms are transported in these wells while remaining confined in all three dimensions. We achieve mean fluxes up to 10(6) s(-1) with a negligible heating rate. An extension of this device allows merging of atom clouds by unification of two Ioffe-Pritchard potentials. The unification, which we demonstrate experimentally, can be performed without loss of phase space density. This novel, all-magnetic atom manipulation offers exciting perspectives, such as trapped-atom interferometry.

  10. Contribution to coherent atom optics - Design of multiple wave devices

    International Nuclear Information System (INIS)

    Impens, F.

    2008-03-01

    The theoretical work presented in this manuscript addresses two complementary issues in coherent atom optics. The first part addresses the perspectives offered by coherent atomic sources through the design of two experiment involving the levitation of a cold atomic sample in a periodic series of light pulses, and for which coherent atomic clouds are particularly well-suited. These systems appear as multiple wave atom interferometers. A striking feature of these experiments is that a unique system performs both the sample trapping and interrogation. To obtain a transverse confinement, a novel atomic lens is proposed, relying on the interaction between an atomic wave with a spherical light wave. The sensitivity of the sample trapping towards the gravitational acceleration and towards the pulse frequencies is exploited to perform the desired measurement. These devices constitute atomic wave resonators in momentum space, which is a novel concept in atom optics. A second part develops new theoretical tools - most of which inspired from optics - well-suited to describe the propagation of coherent atomic sources. A phase-space approach of the propagation, relying on the evolution of moments, is developed and applied to study the low-energy dynamics of Bose-Einstein condensates. The ABCD method of propagation for atomic waves is extended beyond the linear regime to account perturbatively for mean-field atomic interactions in the atom-optical aberration-less approximation. A treatment of the atom laser extraction enabling one to describe aberrations in the atomic beam, developed in collaboration with the Atom Optics group at the Institute of Optics, is exposed. Last, a quality factor suitable for the characterization of diluted matter waves in a general propagation regime has been proposed. (author)

  11. Binary and ternary chelates of scandium (III), Yttrium (III) and lanthanum (III) with ethyleneglycol-bis(. beta. -aminoethylether)-tetraacetic acid as primary and substituted salicylic acids as secondary ligands

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, A K; Chandra, M; Agarwala, B V; Dey, A K [Allahabad Univ. (India). Chemical Labs.

    1980-01-01

    Formation constants of binary and ternary complexes of the systems of the type: M-L and M-egta-L (M = scandium(III), yttrium(III) and lanthanum(III), egta = ethylene glycol-bis(..beta..-aminoethylether)-tetra acetic acid, L = o-cresotic acid (o-ca), m-cresotic acid (m-ca), 5-chlorosalicyclic acid(csa), and 3,5-dibromosalicylic acid (dbsa)) have been determined pH-metrically at 25deg and ..mu.. = 0.1M (KNO/sub 3/) in 50% (v/v) aqueous-ethanol medium. The order of stabilities of ternary complexes has been compared with those of corresponding binary complexes, and results discussed on the basis of coulombic interactions.

  12. Assessment and Risk Mitigation Strategies for the Atom Interferometer Gravity Gradiometer Seed Lasers

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA GSFC has been working on an ESTO IIP - Cold Atom Gravity Gradiometer (CAGG)/Atom Interferometer Gravity Gradiometer (AIGG) for Geodesy since 2014 (Saif/551 –...

  13. Atomic Layer Deposition to Enable the Production, Optimization and Protection of Spaceflight Hardware

    Data.gov (United States)

    National Aeronautics and Space Administration — Atomic Layer Deposition (ALD) a cost effective nano-manufacturing technique allows for the conformal coating of substrates with atomic control in a benign...

  14. Atomic Layer Deposition to Enable the Production, Optimization and Protection of Spaceflight Hardware Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Atomic Layer Deposition (ALD) a cost effective nano-manufacturing technique allows for the conformal coating of substrates with atomic control in a benign...

  15. Permutation-invariant distance between atomic configurations

    Science.gov (United States)

    Ferré, Grégoire; Maillet, Jean-Bernard; Stoltz, Gabriel

    2015-09-01

    We present a permutation-invariant distance between atomic configurations, defined through a functional representation of atomic positions. This distance enables us to directly compare different atomic environments with an arbitrary number of particles, without going through a space of reduced dimensionality (i.e., fingerprints) as an intermediate step. Moreover, this distance is naturally invariant through permutations of atoms, avoiding the time consuming associated minimization required by other common criteria (like the root mean square distance). Finally, the invariance through global rotations is accounted for by a minimization procedure in the space of rotations solved by Monte Carlo simulated annealing. A formal framework is also introduced, showing that the distance we propose verifies the property of a metric on the space of atomic configurations. Two examples of applications are proposed. The first one consists in evaluating faithfulness of some fingerprints (or descriptors), i.e., their capacity to represent the structural information of a configuration. The second application concerns structural analysis, where our distance proves to be efficient in discriminating different local structures and even classifying their degree of similarity.

  16. Permutation-invariant distance between atomic configurations

    International Nuclear Information System (INIS)

    Ferré, Grégoire; Maillet, Jean-Bernard; Stoltz, Gabriel

    2015-01-01

    We present a permutation-invariant distance between atomic configurations, defined through a functional representation of atomic positions. This distance enables us to directly compare different atomic environments with an arbitrary number of particles, without going through a space of reduced dimensionality (i.e., fingerprints) as an intermediate step. Moreover, this distance is naturally invariant through permutations of atoms, avoiding the time consuming associated minimization required by other common criteria (like the root mean square distance). Finally, the invariance through global rotations is accounted for by a minimization procedure in the space of rotations solved by Monte Carlo simulated annealing. A formal framework is also introduced, showing that the distance we propose verifies the property of a metric on the space of atomic configurations. Two examples of applications are proposed. The first one consists in evaluating faithfulness of some fingerprints (or descriptors), i.e., their capacity to represent the structural information of a configuration. The second application concerns structural analysis, where our distance proves to be efficient in discriminating different local structures and even classifying their degree of similarity

  17. Real space process algebra

    NARCIS (Netherlands)

    Bergstra, J.A.; Baeten, J.C.M.

    1993-01-01

    The real time process algebra of Baeten and Bergstra [Formal Aspects of Computing, 3, 142-188 (1991)] is extended to real space by requiring the presence of spatial coordinates for each atomic action, in addition to the required temporal attribute. It is found that asynchronous communication

  18. Atomic collisions research with excited atomic species

    International Nuclear Information System (INIS)

    Hoogerland, M.D.; Gulley, R.J.; Colla, M.; Lu, W.; Milic, D.; Baldwin, K.G.H.; Buckman, S.J.

    1999-01-01

    Measurements and calculations of fundamental atomic collision and spectroscopic properties such as collision cross sections, reaction rates, transition probabilities etc. underpin the understanding and operation of many plasma and gas-discharge-based devices and phenomena, for example plasma processing and deposition. In almost all cases the complex series of reactions which sustains the discharge or plasma, or produces the reactive species of interest, has a precursor electron impact excitation, attachment, dissociation or ionisation event. These processes have been extensively studied in a wide range of atomic and molecular species and an impressive data base of collision cross sections and reaction rates now exists. However, most of these measurements are for collisions with stable atomic or molecular species which are initially in their ground electronic state. Relatively little information is available for scattering from excited states or for scattering from unstable molecular radicals. Examples of such species would be metastable excited rare gases, which are often used as buffer gases, or CF 2 radicals formed by electron impact dissociation in a CF 4 plasma processing discharge. We are interested in developing experimental techniques which will enable the quantitative study of such exotic atomic and molecular species. In this talk I would like to outline one such facility which is being used for studies of collisions with metastable He(2 3 S) atoms

  19. Atoms - molecules - nuclei. Vol. 1

    International Nuclear Information System (INIS)

    Otter, G.; Honecker, R.

    1993-01-01

    This first volume covers the following topics: Wave-particle dualism, classical atomic physics; the Schroedinger equation, angular momentum in quantum physics, one-electron atoms and many-electron atoms with atomic structure, atomic spectra, exotic atoms, influence of electric and magnetic fields

  20. Reactivity of amino acid anions with nitrogen and oxygen atoms.

    Science.gov (United States)

    Wang, Zhe-Chen; Li, Ya-Ke; He, Sheng-Gui; Bierbaum, Veronica M

    2018-02-14

    For many decades, astronomers have searched for biological molecules, including amino acids, in the interstellar medium; this endeavor is important for investigating the hypothesis of the origin of life from space. The space environment is complex and atomic species, such as nitrogen and oxygen atoms, are widely distributed. In this work, the reactions of eight typical deprotonated amino acids (glycine, alanine, cysteine, proline, aspartic acid, histidine, tyrosine, and tryptophan) with ground state nitrogen and oxygen atoms are studied by experiment and theory. These amino acid anions do not react with nitrogen atoms. However, the reactions of these ions with oxygen atoms show an intriguing variety of ionic products and the reaction rate constants are of the order of 10 -10 cm 3 s -1 . Density functional calculations provide detailed mechanisms of the reactions, and demonstrate that spin conversion is essential for some processes. Our study provides important data and insights for understanding the kinetic and dynamic behavior of amino acids in space environments.

  1. MISSE PEACE Polymers Atomic Oxygen Erosion Results

    Science.gov (United States)

    deGroh, Kim, K.; Banks, Bruce A.; McCarthy, Catherine E.; Rucker, Rochelle N.; Roberts, Lily M.; Berger, Lauren A.

    2006-01-01

    Forty-one different polymer samples, collectively called the Polymer Erosion and Contamination Experiment (PEACE) Polymers, have been exposed to the low Earth orbit (LEO) environment on the exterior of the International Space Station (ISS) for nearly 4 years as part of Materials International Space Station Experiment 2 (MISSE 2). The objective of the PEACE Polymers experiment was to determine the atomic oxygen erosion yield of a wide variety of polymeric materials after long term exposure to the space environment. The polymers range from those commonly used for spacecraft applications, such as Teflon (DuPont) FEP, to more recently developed polymers, such as high temperature polyimide PMR (polymerization of monomer reactants). Additional polymers were included to explore erosion yield dependence upon chemical composition. The MISSE PEACE Polymers experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), tray 1, on the exterior of the ISS Quest Airlock and was exposed to atomic oxygen along with solar and charged particle radiation. MISSE 2 was successfully retrieved during a space walk on July 30, 2005, during Discovery s STS-114 Return to Flight mission. Details on the specific polymers flown, flight sample fabrication, pre-flight and post-flight characterization techniques, and atomic oxygen fluence calculations are discussed along with a summary of the atomic oxygen erosion yield results. The MISSE 2 PEACE Polymers experiment is unique because it has the widest variety of polymers flown in LEO for a long duration and provides extremely valuable erosion yield data for spacecraft design purposes.

  2. Atomic and molecular sciences

    International Nuclear Information System (INIS)

    Lane, N.F.

    1989-01-01

    The theoretical atomic and molecular physics program at Rice University addresses basic questions about the collision dynamics of electrons, atoms, ions and molecules, emphasizing processes related to possible new energy technologies and other applications. The program focuses on inelastic collision processes that are important in understanding energy and ionization balance in disturbed gases and plasmas. Emphasis is placed on systems and processes where some experimental information is available or where theoretical results may be expected to stimulate new measurements. Examples of current projects include: excitation and charge-transfer processes; orientation and alignment of excited states following collisions; Rydberg atom collisions with atoms and molecules; Penning ionization and ion-pair formation in atom-atom collisions; electron-impact ionization in dense, high-temperature plasmas; electron-molecule collisions; and related topics

  3. Modern atomic physics

    CERN Document Server

    Natarajan, Vasant

    2015-01-01

    Much of our understanding of physics in the last 30-plus years has come from research on atoms, photons, and their interactions. Collecting information previously scattered throughout the literature, Modern Atomic Physics provides students with one unified guide to contemporary developments in the field. After reviewing metrology and preliminary material, the text explains core areas of atomic physics. Important topics discussed include the spontaneous emission of radiation, stimulated transitions and the properties of gas, the physics and applications of resonance fluorescence, coherence, cooling and trapping of charged and neutral particles, and atomic beam magnetic resonance experiments. Covering standards, a different way of looking at a photon, stimulated radiation, and frequency combs, the appendices avoid jargon and use historical notes and personal anecdotes to make the topics accessible to non-atomic physics students. Written by a leader in atomic and optical physics, this text gives a state-of-the...

  4. Cold atomic beams of high brightness

    International Nuclear Information System (INIS)

    Rozhdestvensky, Yu V

    2004-01-01

    The possibility is studied for obtaining intense cold atomic beams by using the Renyi entropy to optimise the laser cooling process. It is shown in the case of a Gaussian velocity distribution of atoms, the Renyi entropy coincides with the density of particles in the phase space. The optimisation procedure for cooling atoms by resonance optical radiation is described, which is based on the thermodynamic law of increasing the Renyi entropy in time. Our method is compared with the known methods for increasing the laser cooling efficiency such as the tuning of a laser frequency in time and a change of the atomic transition frequency in an inhomogeneous transverse field of a magnetic solenoid. (laser cooling)

  5. Metal atom oxidation laser

    International Nuclear Information System (INIS)

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-01-01

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides

  6. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  7. Economical Atomic Layer Deposition

    Science.gov (United States)

    Wyman, Richard; Davis, Robert; Linford, Matthew

    2010-10-01

    Atomic Layer Deposition is a self limiting deposition process that can produce films at a user specified height. At BYU we have designed a low cost and automated atomic layer deposition system. We have used the system to deposit silicon dioxide at room temperature using silicon tetrachloride and tetramethyl orthosilicate. Basics of atomic layer deposition, the system set up, automation techniques and our system's characterization are discussed.

  8. Atomic physics made clear

    International Nuclear Information System (INIS)

    Meinhold, H.

    1980-01-01

    This book is a popular introduction into the foundations of atomic physics und quantum mechanics. Starting from some phenomenological concepts Bohr's model and the construction of the periodic system regarding the shell structure of atoms are introduced. In this framework the selection rules and magnetic moments of atomic electrons are considered. Finally the wave-particle dualism is considered. In the appendix some mathematical methods are described which are useful for a deeper penetration into the considered ideas. (HSI)

  9. Continuous measurement of an atomic current

    Science.gov (United States)

    Laflamme, C.; Yang, D.; Zoller, P.

    2017-04-01

    We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice models, including the Hubbard model. We describe a Cavity QED setup, where measurement of a homodyne current provides a faithful representation of the atomic current as a function of time. We employ the quantum optical description in terms of a diffusive stochastic Schrödinger equation to follow the time evolution of the atomic system conditional to observing a given homodyne current trajectory, thus accounting for the competition between the Hamiltonian evolution and measurement back action. As an illustration, we discuss minimal models of atomic dynamics and continuous current measurement on rings with synthetic gauge fields, involving both real space and synthetic dimension lattices (represented by internal atomic states). Finally, by "not reading" the current measurements the time evolution of the atomic system is governed by a master equation, where—depending on the microscopic details of our CQED setups—we effectively engineer a current coupling of our system to a quantum reservoir. This provides interesting scenarios of dissipative dynamics generating "dark" pure quantum many-body states.

  10. Quantum Spin Lenses in Atomic Arrays

    Directory of Open Access Journals (Sweden)

    A. W. Glaetzle

    2017-09-01

    Full Text Available We propose and discuss quantum spin lenses, where quantum states of delocalized spin excitations in an atomic medium are focused in space in a coherent quantum process down to (essentially single atoms. These can be employed to create controlled interactions in a quantum light-matter interface, where photonic qubits stored in an atomic ensemble are mapped to a quantum register represented by single atoms. We propose Hamiltonians for quantum spin lenses as inhomogeneous spin models on lattices, which can be realized with Rydberg atoms in 1D, 2D, and 3D, and with strings of trapped ions. We discuss both linear and nonlinear quantum spin lenses: in a nonlinear lens, repulsive spin-spin interactions lead to focusing dynamics conditional to the number of spin excitations. This allows the mapping of quantum superpositions of delocalized spin excitations to superpositions of spatial spin patterns, which can be addressed by light fields and manipulated. Finally, we propose multifocal quantum spin lenses as a way to generate and distribute entanglement between distant atoms in an atomic lattice array.

  11. Deeply bound pionic atom

    International Nuclear Information System (INIS)

    Toki, Hiroshi; Yamazaki, Toshimitsu

    1989-01-01

    The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ - ) cross sections are estimated. (p, 2 Heπ - ) reaction would have cross sections similar to the cross section of (n, dπ - ) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)

  12. Single atom oscillations

    International Nuclear Information System (INIS)

    Wiorkowski, P.; Walther, H.

    1990-01-01

    Modern methods of laser spectroscopy allow the study of single atoms or ions in an unperturbed environment. This has opened up interesting new experiments, among them the detailed study of radiation-atom coupling. In this paper, the following two experiments dealing with this problem are reviewed: the single-atom maser and the study of the resonance fluorescence of a single stored ion. The simplest and most fundamental system for studying radiation-matter coupling is a single two-level atom interacting with a single mode of an electromagnetic field in a cavity. This problem received a great deal of attention shortly after the maser was invented

  13. Atomic hydrogen reactor

    International Nuclear Information System (INIS)

    Massip de Turville, C.M.D.

    1982-01-01

    Methods are discussed of generating heat in an atomic hydrogen reactor which involve; the production of atomic hydrogen by an electrical discharge, the capture of nascent neutrons from atomic hydrogen in a number of surrounding steel alloy tubes having a high manganese content to produce 56 Mn, the irradiation of atomic hydrogen by the high energy antineutrinos from the beta decay of 56 Mn to yield nascent neutrons, and the removal of the heat generated by the capture of nascent neutrons by 55 Mn and the beta decay of 56 Mn. (U.K.)

  14. About the correlation between atomic charge fluctuations in a molecule

    International Nuclear Information System (INIS)

    Pitanga, P.; Giambiagi, M.S. de; Giambiagi, M.

    1987-01-01

    In this note, the features of the correlation between the electronic charge fluctuations of a pair of atoms within a molecule are analised. Through Schwarz's inequality for random operators in the Hilbert space, the softness of an atom in a molecule is related to its valence and to the softness of the other atoms. It is concluded that in the general case this correlation (from which in turn stems the chemical bond) in non-linear. (author) [pt

  15. Atom dynamics in laser fields

    International Nuclear Information System (INIS)

    Jang, Su; Mi, No Gin

    2004-12-01

    This book introduces coherent dynamics of internal state, spread of atoms wave speed, semiclassical atoms density matrix such as dynamics equation in both still and moving atoms, excitation of atoms in movement by light, dipole radiating power, quantum statistical mechanics by atoms in movement, semiclassical atoms in movement, atoms in movement in the uniform magnetic field including effects of uniform magnetic field, atom cooling using laser such as Doppler cooling, atom traps using laser and mirrors, radiant heat which particles receive, and near field interactions among atoms in laser light.

  16. High-Flux Ultracold-Atom Chip Interferometers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ColdQuanta's ultimate objective is to produce a compact, turnkey, ultracold-atom system specifically designed for performing interferometry with Bose-Einstein...

  17. Multi-channel tunable source for atomic sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR will establish the feasibility of developing compact, robust, integrated components suitable for atomic interferometry. AdvR's design is enabled by...

  18. Multi-Channel Tunable Source for Atomic Sensors, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase II SBIR will seek to develop a prototype laser source suitable for atomic interferometry from compact, robust, integrated components. AdvR's design is...

  19. Atoms stories; Histoire d`atomes

    Energy Technology Data Exchange (ETDEWEB)

    Radvanyi, P; Bordry, M [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)

    1988-12-31

    Physicists from different countries told each evening during one learning week, to an audience of young people, some great discoveries in evoking the difficulties and problems to which the researchers were confronted. From Antiquity to a more recent history, it is a succession of atoms stories. (N.C.)

  20. Low energy atom-atom collisions

    International Nuclear Information System (INIS)

    Child, M.S.

    1980-01-01

    The semiclassical theory of atom-atom potential scattering and of low energy inelastic atom-atom scattering is reviewed. Particular attention is given to the origin and interpretation of rainbow structure, diffraction oscillations and exchange oscillations in the potential scattering differential cross-section, and to the glory structure and symmetry oscillations in the integral cross-section. Available methods for direct inversion of the cross-section data to recover the potential are reviewed in some detail. The theory of non-adiabatic transitions is introduced by a short discussion of interaction mechanisms and of diabetic and adiabatic representations. Analytical S matrix elements are presented for two state curve-crossing (Landau-Zener-Stuckelberg), Demkov and Nikitin models. The relation between Stuckelberg oscillations in the S matrix and in the differential cross-section is discussed in terms of interference between trajectories belonging to two different classical deflection functions. The energy dependences of the inelastic integral cross-section for curve-crossing and Demkov type transitions are also discussed. Finally the theory is reviewed in relation to a recent close-coupled study of fine structure transitions in F( 2 P) + Xe( 2 S) scattering

  1. Single-Atom Gating of Quantum State Superpositions

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Christopher

    2010-04-28

    The ultimate miniaturization of electronic devices will likely require local and coherent control of single electronic wavefunctions. Wavefunctions exist within both physical real space and an abstract state space with a simple geometric interpretation: this state space - or Hilbert space - is spanned by mutually orthogonal state vectors corresponding to the quantized degrees of freedom of the real-space system. Measurement of superpositions is akin to accessing the direction of a vector in Hilbert space, determining an angle of rotation equivalent to quantum phase. Here we show that an individual atom inside a designed quantum corral1 can control this angle, producing arbitrary coherent superpositions of spatial quantum states. Using scanning tunnelling microscopy and nanostructures assembled atom-by-atom we demonstrate how single spins and quantum mirages can be harnessed to image the superposition of two electronic states. We also present a straightforward method to determine the atom path enacting phase rotations between any desired state vectors. A single atom thus becomes a real-space handle for an abstract Hilbert space, providing a simple technique for coherent quantum state manipulation at the spatial limit of condensed matter.

  2. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  3. Atomic Energy Control Board

    International Nuclear Information System (INIS)

    Blackman, N.S.; Gummer, W.K.

    1982-02-01

    This paper has been prepared to provide an overview of the responsibilities and activities of the Atomic Energy Control Board. It is designed to address questions that are often asked concerning the establishment of the Atomic Energy Control Board, its enabling legislation, licensing and compliance activities, federal-provincial relationships, international obligations, and communications with the public

  4. mu. -nucleon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Dobretsov, Yu; Dolgoshein, B; Kirillov-Ugryumov, V

    1980-12-01

    The properties and formation are described of ..mu..-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of ..mu..-nucleon atoms is shown. The prospects of their use are indicated.

  5. μ-nucleon atoms

    International Nuclear Information System (INIS)

    Dobretsov, Yu.; Dolgoshejn, B.; Kirillov-Ugryumov, V.

    1980-01-01

    The properties and formation are described of μ-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of μ-nucleon atoms is shown. The prospects of their use are indicated. (J.P.)

  6. Atom lithography of Fe

    NARCIS (Netherlands)

    Sligte, te E.; Smeets, B.; van der Stam, K.M.R.; Herfst, R.W.; Straten, van der P.; Beijerinck, H.C.W.; Leeuwen, van K.A.H.

    2004-01-01

    Direct write atom lithography is a technique in which nearly resonant light is used to pattern an atom beam. Nanostructures are formed when the patterned beam falls onto a substrate. We have applied this lithography scheme to a ferromagnetic element, using a 372 nm laser light standing wave to

  7. Beyond the Atom

    Science.gov (United States)

    Cox, John

    2011-08-01

    1. Introduction - the atom in the seventies; 2. The vacuum tube; 3. The new rays; 4. The new substances; 5. Disintegration; 6. A family tree; 7. Verifications and results; 8. The objective reality of molecules; 9. The new atom; Bibliography; Index.

  8. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  9. Atom electron scattering

    International Nuclear Information System (INIS)

    Santoso, B.

    1976-01-01

    Green Lippmann-Schwinger functions operator representations, derivation of perturbation method using Green function and atom electron scattering, are discussed. It is concluded that by using complex coordinate places where resonances occur, can be accurately identified. The resonance can be processed further for practical purposes, for example for the separation of atom. (RUW)

  10. Atomic energy for progress

    International Nuclear Information System (INIS)

    1974-01-01

    The film discusses the functions and activities of the Philippine Atomic Energy Commission. Shown are the applications of atomic energy in research, agriculture, engineering, industry and medicine, as well as the construction of the research reactor and its inauguration by President Marcos

  11. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Loos-Vollebregt, M.T.C. de.

    1980-01-01

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  12. Isotopes and atomic weights

    International Nuclear Information System (INIS)

    Zhang Qinglian

    1990-01-01

    A review of the chemical and mass spectrometric methods of determining the atomic weights of elements is presented. A, special discussion is devoted to the calibration of the mass spectrometer with highly enriched isotopes. It is illustrated by the recent work on europium. How to choose the candidate element for new atomic weight determination forms the last section of the article

  13. The Scales of Time, Length, Mass, Energy, and Other Fundamental Physical Quantities in the Atomic World and the Use of Atomic Units in Quantum Mechanical Calculations

    Science.gov (United States)

    Teo, Boon K.; Li, Wai-Kee

    2011-01-01

    This article is divided into two parts. In the first part, the atomic unit (au) system is introduced and the scales of time, space (length), and speed, as well as those of mass and energy, in the atomic world are discussed. In the second part, the utility of atomic units in quantum mechanical and spectroscopic calculations is illustrated with…

  14. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  15. Theoretical atomic physics

    CERN Document Server

    Friedrich, Harald

    2017-01-01

    This expanded and updated well-established textbook contains an advanced presentation of quantum mechanics adapted to the requirements of modern atomic physics. It includes topics of current interest such as semiclassical theory, chaos, atom optics and Bose-Einstein condensation in atomic gases. In order to facilitate the consolidation of the material covered, various problems are included, together with complete solutions. The emphasis on theory enables the reader to appreciate the fundamental assumptions underlying standard theoretical constructs and to embark on independent research projects. The fourth edition of Theoretical Atomic Physics contains an updated treatment of the sections involving scattering theory and near-threshold phenomena manifest in the behaviour of cold atoms (and molecules). Special attention is given to the quantization of weakly bound states just below the continuum threshold and to low-energy scattering and quantum reflection just above. Particular emphasis is laid on the fundamen...

  16. Antiprotonic-hydrogen atoms

    International Nuclear Information System (INIS)

    Batty, C.J.

    1989-07-01

    Experimental studies of antiprotonic-hydrogen atoms have recently made great progress following the commissioning of the low energy antiproton facility (LEAR) at CERN in 1983. At the same time our understanding of the atomic cascade has increased considerably through measurements of the X-ray spectra. The life history of the p-bar-p atom is considered in some detail, from the initial capture of the antiproton when stopping in hydrogen, through the atomic cascade with the emission of X-rays, to the final antiproton annihilation and production of mesons. The experiments carried out at LEAR are described and the results compared with atomic cascade calculations and predictions of strong interaction effects. (author)

  17. Physics for all, who want to join in conversation. On atomic power, dirty bombs, space research, solar energy, and the global heating; Physik fuer alle, die mitreden wollen. Ueber Atomkraft, schmutzige Bomben, Weltraumforschung, Solarenergie und die globale Erwaermung

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Richard A.

    2009-07-01

    Which dangers contains the global heating really? What can happen at an attack on a atomic power plant?. Which chances offer renewable energies? Questions which are put daily in the pursuing of news - but to which we have only seldomly answers ready, because basic physical knowledge is absent. But it must not even be the great world policy. Already at the decision wether solar cells shall be mounted on the roof or punted on geothermal heat physics are not unimportant. More often than we think it are natural sciences, which yield the foundations for important decisions. Richard A. Muller explains simply and illustratively, how physics determines our life. Thereby he removes prejudices and mediates quite surprising insights.

  18. Experimental atomic physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The experimental atomic physics program within the physics division is carried out by two groups, whose reports are given in this section. Work of the accelerator atomic physics group is centered around the 6.5-MV EN tandem accelerator; consequently, most of its research is concerned with atomic processes occurring to, or initiated by, few MeV/amu heavy ions. Other activities of this group include higher energy experiments at the Holifield Heavy Ion Research Facility (HHIRF), studies of electron and positron channeling radiation, and collaborative experiments at other institutions. The second experimental group concerns itself with lower energy atomic collision physics in support of the Fusion Energy Program. During the past year, the new Electron Cyclotron Resonance Source has been completed and some of the first data from this facility is presented. In addition to these two activities in experimental atomic physics, other chapters of this report describe progress in theoretical atomic physics, experimental plasma diagnostic development, and atomic data center compilation activities

  19. Probing dark energy with atom interferometry

    International Nuclear Information System (INIS)

    Burrage, Clare; Copeland, Edmund J.; Hinds, E.A.

    2015-01-01

    Theories of dark energy require a screening mechanism to explain why the associated scalar fields do not mediate observable long range fifth forces. The archetype of this is the chameleon field. Here we show that individual atoms are too small to screen the chameleon field inside a large high-vacuum chamber, and therefore can detect the field with high sensitivity. We derive new limits on the chameleon parameters from existing experiments, and show that most of the remaining chameleon parameter space is readily accessible using atom interferometry

  20. Probing dark energy with atom interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare; Copeland, Edmund J. [School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Hinds, E.A., E-mail: Clare.Burrage@nottingham.ac.uk, E-mail: Edmund.Copeland@nottingham.ac.uk, E-mail: Ed.Hinds@imperial.ac.uk [Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

    2015-03-01

    Theories of dark energy require a screening mechanism to explain why the associated scalar fields do not mediate observable long range fifth forces. The archetype of this is the chameleon field. Here we show that individual atoms are too small to screen the chameleon field inside a large high-vacuum chamber, and therefore can detect the field with high sensitivity. We derive new limits on the chameleon parameters from existing experiments, and show that most of the remaining chameleon parameter space is readily accessible using atom interferometry.

  1. From hot atom chemistry to epithermal chemistry

    International Nuclear Information System (INIS)

    Roessler, K.

    2004-01-01

    The rise and fall of hot atom chemistry (HAC) over the years from 1934 to 2004 is reviewed. Several applications are discussed, in particular to astrophysics and the interaction of energetic ions and atoms in space. Epithermal chemistry (ETC) is proposed to substitute the old name, since it better fits the energy range as well as the non-thermal and non-equilibrium character of the reactions. ETC also avoids the strong connexion of HAC to nuclear chemistry and stands for the opening of the field to physical chemistry and astrophysics. (orig.)

  2. Optical atomic phase reference and timing.

    Science.gov (United States)

    Hollberg, L; Cornell, E H; Abdelrahmann, A

    2017-08-06

    Atomic clocks based on laser-cooled atoms have made tremendous advances in both accuracy and stability. However, advanced clocks have not found their way into widespread use because there has been little need for such high performance in real-world/commercial applications. The drive in the commercial world favours smaller, lower-power, more robust compact atomic clocks that function well in real-world non-laboratory environments. Although the high-performance atomic frequency references are useful to test Einstein's special relativity more precisely, there are not compelling scientific arguments to expect a breakdown in special relativity. On the other hand, the dynamics of gravity, evidenced by the recent spectacular results in experimental detection of gravity waves by the LIGO Scientific Collaboration, shows dramatically that there is new physics to be seen and understood in space-time science. Those systems require strain measurements at less than or equal to 10 -20 As we discuss here, cold atom optical frequency references are still many orders of magnitude away from the frequency stability that should be achievable with narrow-linewidth quantum transitions and large numbers of very cold atoms, and they may be able to achieve levels of phase stability, Δ Φ / Φ total  ≤ 10 -20 , that could make an important impact in gravity wave science.This article is part of the themed issue 'Quantum technology for the 21st century'. © 2017 The Author(s).

  3. Optical atomic phase reference and timing

    Science.gov (United States)

    Hollberg, L.; Cornell, E. H.; Abdelrahmann, A.

    2017-06-01

    Atomic clocks based on laser-cooled atoms have made tremendous advances in both accuracy and stability. However, advanced clocks have not found their way into widespread use because there has been little need for such high performance in real-world/commercial applications. The drive in the commercial world favours smaller, lower-power, more robust compact atomic clocks that function well in real-world non-laboratory environments. Although the high-performance atomic frequency references are useful to test Einstein's special relativity more precisely, there are not compelling scientific arguments to expect a breakdown in special relativity. On the other hand, the dynamics of gravity, evidenced by the recent spectacular results in experimental detection of gravity waves by the LIGO Scientific Collaboration, shows dramatically that there is new physics to be seen and understood in space-time science. Those systems require strain measurements at less than or equal to 10-20. As we discuss here, cold atom optical frequency references are still many orders of magnitude away from the frequency stability that should be achievable with narrow-linewidth quantum transitions and large numbers of very cold atoms, and they may be able to achieve levels of phase stability, ΔΦ/Φtotal ≤ 10-20, that could make an important impact in gravity wave science. This article is part of the themed issue 'Quantum technology for the 21st century'.

  4. Nuclear Energy in Space Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Seaborg, Glenn T.

    1968-01-01

    Nuclear space programs under development by the Atomic Energy Commission are reviewed including the Rover Program, systems for nuclear rocket propulsion and, the SNAP Program, systems for generating electric power in space. The letters S-N-A-P stands for Systems for Nuclear Auxiliary Power. Some of the projected uses of nuclear systems in space are briefly discussed including lunar orbit, lunar transportation from lunar orbit to lunar surface and base stations; planetary exploration, and longer space missions. The limitations of other sources of energy such as solar, fuel cells, and electric batteries are discussed. The excitement and visionary possibilities of the Age of Space are discussed.

  5. Atomic mass spectrometry

    International Nuclear Information System (INIS)

    Sanz-Medel, A.

    1997-01-01

    The elemental inorganic analysis seems to be dominated today by techniques based on atomic spectrometry. After an evaluation of advantages and limitations of using mass analysers (ion detectors) versus conventional photomultipliers (photon detector) a brief review of the more popular techniques of the emerging Atomic Mass spectrometry is carried out. Their huge potential for inorganic trace analysis is such that in the future we could well witness how this end of the century and millennium marked the fall of the photons empire in Analytical Atomic Spectrometry. (Author)

  6. Physics of the atom

    CERN Document Server

    Wehr, Russell M; Adair, Thomas W

    1984-01-01

    The fourth edition of Physics of the Atom is designed to meet the modern need for a better understanding of the atomic age. It is an introduction suitable for students with a background in university physics and mathematical competence at the level of calculus. This book is designed to be an extension of the introductory university physics course into the realm of atomic physics. It should give students a proficiency in this field comparable to their proficiency in mechanics, heat, sound, light, and electricity.

  7. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  8. Division of atomic physics

    International Nuclear Information System (INIS)

    Kroell, S.

    1994-01-01

    The Division of Atomic Physics, Lund Institute of Technology (LTH), is responsible for the basic physics teaching in all subjects at LTH and for specialized teaching in Optics, Atomic Physics, Atomic and Molecular Spectroscopy and Laser Physics. The Division has research activities in basic and applied optical spectroscopy, to a large extent based on lasers. It is also part of the Physics Department, Lund University, where it forms one of eight divisions. Since the beginning of 1980 the research activities of our division have been centred around the use of lasers. The activities during the period 1991-1992 is described in this progress reports

  9. Atom trap trace analysis

    International Nuclear Information System (INIS)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-01-01

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual 85 Kr and 81 Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10 -11 and 10 -13 , respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications

  10. Thermal effects on the stability of excited atoms in cavities

    International Nuclear Information System (INIS)

    Khanna, F. C.; Malbouisson, A. P. C.; Malbouisson, J. M. C.; Santana, A. E.

    2010-01-01

    An atom, coupled linearly to an environment, is considered in a harmonic approximation in thermal equilibrium inside a cavity. The environment is modeled by an infinite set of harmonic oscillators. We employ the notion of dressed states to investigate the time evolution of the atom initially in the first excited level. In a very large cavity (free space) for a long elapsed time, the atom decays and the value of its occupation number is the physically expected one at a given temperature. For a small cavity the excited atom never completely decays and the stability rate depends on temperature.

  11. Section of Atomic Collisions

    International Nuclear Information System (INIS)

    Berenyi, D.; Biri, S.; Gulyas, L.; Juhasz, Z.; Kover, A.; Orban, A.; Palinkas, J.; Papp, T.; Racz, R.; Ricz, S.

    2009-01-01

    The Section of Atomic Collisions is a research unit with extended activity in the field of atomic and molecular physics. Starting from the study of atomic processes at the beamlines of nuclear physics accelerators in the seventies, our research community became one of the centers of fundamental research in Atomki. We also have a strong connection to materials sciences especially along the line of electron and ion spectroscopy methods. Our present activity covers a wide range of topics from atomic collision mechanisms of fundamental interest, to the complex interactions of electrons, ions, photons and antiparticles with atoms, molecules, surfaces, and specific nanostructures. In the last few years, an increasing fraction of our present topics has become relevant for applications, e.g., molecular collision studies for the radiation therapy methods of tumors, or ion-nanostructure interactions for the future construction of small ion-focusing elements. Our section belongs to the Division of Atomic Physics. The other unit of the Division is the Section of Electron Spectroscopy and Materials Sciences. There are traditionally good connections and a strong collaboration between the groups of the two sections in many fields. From the very beginning of our research work in atomic collisions, external collaborations were of vital importance for us. We regularly organize international workshops in the field of fast ion-atom collisions and related small conferences in Debrecen from 1981. Recently, we organized the Conference on Radiation Damage in Biomolecular Systems (RADAM 2008, Debrecen), and coorganized the Conference on Elementary Processes in Atomic Systems (CEPAS 2008, Cluj). We have access to several large scale facilities in Europe within the framework of formal and informal collaborations. The next themes are in this article: Forward electron emission from energetic atomic collisions; Positron-atom collisions; Photon-atom interactions; Interference effects in electron

  12. History of early atomic clocks

    International Nuclear Information System (INIS)

    Ramsey, N.F.

    2005-01-01

    This review of the history of early atomic clocks includes early atomic beam magnetic resonance, methods of separated and successive oscillatory fields, microwave absorption, optical pumping and atomic masers. (author)

  13. Asymptotics of Rydberg states for the hydrogen atom

    International Nuclear Information System (INIS)

    Thomas, L.E.

    1997-01-01

    The asymptotics of Rydberg states, i.e., highly excited bound states of the hydrogen atom Hamiltonian, and various expectations involving these states are investigated. We show that suitable linear combinations of these states, appropriately rescaled and regarded as functions either in momentum space or configuration space, are highly concentrated on classical momentum space or configuration space Kepler orbits respectively, for large quantum numbers. Expectations of momentum space or configuration space functions with respect to these states are related to time-averages of these functions over Kepler orbits. (orig.)

  14. Atomic Energy Authority Bill

    International Nuclear Information System (INIS)

    Gray, J.H.N.; Stoddart, D.L.; Sinclair, R.M.; Ezra, D.

    1985-01-01

    The House, in Committee, discussed the following matters in relation to the Atomic Energy Authority Bill; financing; trading; personnel conditions of employment; public relations; organization; research programmes; fuels; energy sources; information dissemination. (U.K.)

  15. Atomic and Molecular Interactions

    International Nuclear Information System (INIS)

    2002-01-01

    The Gordon Research Conference (GRC) on Atomic and Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field

  16. Zeeman atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given

  17. Optics With Cold Atoms

    National Research Council Canada - National Science Library

    Hau, Lene

    2004-01-01

    .... And to test the novel atom sensor, we have built a moving-molasses magneto-optical trap in a geometry tailor-suited to the nanotube detector geometry, involving construction of a highly stable laser...

  18. Atomic Energy Control Regulations

    International Nuclear Information System (INIS)

    1992-01-01

    This is the consolidated text of the Atomic Energy Control Regulations of 17 March 1960, with amendments to 27 August 1992. The Regulations cover the licensing of nuclear facilities, radiation sources, including uranium mining, radiation protection questions, etc. (NEA)

  19. The atomic conflict

    International Nuclear Information System (INIS)

    Mez, L.

    1981-01-01

    This book provides a general view at the atomic programmes of several countries and makes an attempt to unmask the atomic industrial combines with their interlockings. The governments role is analysed as well as the atomic policy of the parties, union-trades and associations. Then, the anti-atomic movements in those countries, their forms of resistance, the resonance and the alternative proposals are presented. The countries concerned are Australia, the FRG, COMECON, Danmark, the EG, Finland, France, Great Britain, Ireland, Japan, the Netherlands, Norway, Austria, Sweden, Switzerland, Spain and the USA. For the pocket book version, Lutz Mez adds an updating epilogue which continues with the developments until springtime 1981. (orig./HP) [de

  20. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1998-01-01

    This volume continues the series'' cutting-edge reviews on developments in this field. Since its invention in the 1920s, electrostatic precipitation has been extensively used in industrial hygiene to remove dust and particulate matter from gases before entering the atmosphere. This combination of electrostatic precipitation is reported upon in the first chapter. Following this, chapter two reviews recent advances in the area of chemical modification in electrothermal atomization. Chapter three consists of a review which deal with advances and uses of electrothermal atomization atomic absorption spectrometry. Flow injection atomic spectroscopy has developed rapidly in recent years and after a general introduction, various aspects of this technique are looked at in chapter four. Finally, in chapter five the use of various spectrometric techniques for the determination of mercury are described.

  1. Atoms at work

    International Nuclear Information System (INIS)

    1982-07-01

    This illustrated booklet discusses the following: atoms; fission of uranium; nuclear power plants; reactor types; plutonium (formation, properties, uses); radioactive waste (fuel cycle, reprocessing, waste management); nuclear fusion; fusion reactors; radiation; radioisotopes and their uses. (U.K.)

  2. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  3. Atomic bomb cataracts

    International Nuclear Information System (INIS)

    Shiraeda, Kanji

    1992-01-01

    Eye disturbance caused by atomic bomb radiation can be divided into three groups: direct injury immediately after exposure, eye lesions associated with radiation syndrome, and delayed disturbance. The crystalline lens of the eye is the most radiosensitive. Atomic bomb cataract has been investigated in a number of studies. The first section of this chapter discusses radiation cataract in terms of the incidence and characteristics. The second section deals with atomic bomb cataract, which can be diagnosed based on the four criteria: (1) opacity of the crystalline lens, (2) a history of proximal exposure, (3) lack of eye disease complicating cataract, and (4) non-exposure to radiation other than atomic bombing. The prevalence of cataract and severity of opacity are found to correlate with exposure doses and age at the time of exposure. Furthermore, it is found to correlate with distance from the hypocenter, the condition of shielding, epilation, and the presence or absence or degree of radiation syndrome. (N.K.)

  4. The Atomic Energy Control Board

    International Nuclear Information System (INIS)

    Doern, G.B.

    1976-01-01

    This study describes and assesses the regulatory and administrative processes and procedures of the Atomic Energy Control Board, the AECB. The Atomic Energy Control Act authorized the AECB to control atomic energy materials and equipment in the national interest and to participate in measures for the international control of atomic energy. The AECB is authorized to make regulations to control atomic energy materials and equipment and to make grants in support of atomic energy research. (author)

  5. Energy flux of hot atoms

    International Nuclear Information System (INIS)

    Wotzak, G.P.; Kostin, M.D.

    1976-01-01

    The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

  6. Harnessing the atom

    International Nuclear Information System (INIS)

    1999-01-01

    Splitting the atom has had a major impact on the history of the latter part of the 20th century. This film depicts the many benefits - and also drawbacks - of nuclear technology, and describes how the International Atomic Energy Agency performs its various tasks. It touches on challenges such as the choice between major energy sources, growing concerns about the global climate, and prospects for nuclear arms control and disarmament

  7. Atomic Energy Act 1946

    International Nuclear Information System (INIS)

    1946-01-01

    This Act provides for the development of atomic energy in the United Kingdom and for its control. It details the duties and powers of the competent Minister, in particular his powers to obtain information on and to inspect materials, plant and processes, to control production and use of atomic energy and publication of information thereon. Also specified is the power to search for and work minerals and to acquire property. (NEA) [fr

  8. Hirshfeld atom refinement.

    Science.gov (United States)

    Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-09-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  9. Manipulating atoms with photons

    International Nuclear Information System (INIS)

    Cohen-Tannoudji, C.N.

    1998-01-01

    The article is a translation of the lecture delivered on the occasion of the 1997 Nobel Prize awarding ceremony. The physical mechanisms which allow manipulating of neutral atoms with laser photons are described. A remark is also made concerning several possible applications of ultra-cool atoms and streams of future research. The article is completed by Prof. Cohen-Tannoudji's autobiography. (Z.J.)

  10. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  11. Atomic bomb and leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Ichimaru, M; Tomonaga, M; Amenomori, T; Matsuo, T [Nagasaki Univ. (Japan). School of Medicine

    1991-12-01

    Characteristic features of the leukemia among atomic bomb survivors were studied. Dose estimates of atomic bomb radiation were based on T65D, but the new dosimetry system DS86 was used for some analyses. The ratio of a single leukemia type to all leukemias was highest for chronic myelogenous leukemia (CML) in Hiroshima, and the occurrence of CML was thought to be most characteristic to atomic bomb radiation induced leukemia. The threshold of CML occurrence in Hiroshima is likely to be between 0.5{approx}0.09 Gy. However, the threshold of acute leukemia appears to be nearly 1 Gy. In the distribution of acute myeloid leukemia (AML) subtypes by French-American-British classification, there was no M3 case in 1 Gy or more group, although several atypical AML cases of survivors were observed. Although aplastic anemia has not increased as a late effect of the atomic bomb radiation exposure, many atypical leukemia or other myeloproliferative diseases who had been diagnosed as aplastic anemia or its related diseases have been experienced among atomic bomb survivors. Chromosome study was conducted using colony forming cells induced by hemopoietic stem cells of peripheral blood of proximal survivors. Same chromosome aberrations were observed in colony forming cells and peripheral T-cells in several atomic bomb survivors. (author).

  12. On the bosonic atoms

    Science.gov (United States)

    Amusia, M. Ya.; Chernysheva, L. V.

    2018-01-01

    We investigate ground state properties of atoms, in which substitute fermions - electrons by bosons, namely π --mesons. We perform some calculations in the frame of modified Hartree-Fock (HF) equation. The modification takes into account symmetry, instead of anti-symmetry of the pair identical bosons wave function. The modified HF approach thus enhances (doubles) the effect of self-action for the boson case. Therefore, we accordingly modify the HF equations by eliminating the self-action terms "by hand". The contribution of meson-meson and meson-nucleon non-Coulomb interaction is inessential at least for atoms with low and intermediate nuclear charge, which is our main subject. We found that the binding energy of pion negative ions A π - , pion atoms A π , and the number of extra bound pions ΔN π increases with the growth of nuclear charge Z. For e.g. Xe ΔN π = 4. As an example of a simple process with a pion atom, we consider photoionization that differs essentially from that for electron atoms. Namely, it is not monotonic decreasing from the threshold but has instead a prominent maximum above threshold. We study also elastic scattering of pions by pion atoms.

  13. Electron - atom bremsstrahlung

    International Nuclear Information System (INIS)

    Kim, L.

    1986-01-01

    Features of bremsstrahlung radiation from neutral atoms and atoms in hot dense plasmas are studied. Predictions for the distributions of electron-atom bremsstrahlung radiation for both the point-Coulomb potential and screened potentials are obtained using a classical numerical method. Results agree with exact quantum-mechanical partial-wave results for low incident electron energies in both the point-Coulomb and screened potentials. In the screened potential, the asymmetry parameter of a spectrum is reduced from the Coulomb values. The difference increases with decreasing energy and begins to oscillate at very low energies. The scaling properties of bremsstrahlung spectra and energy losses were also studied. It was found that the ratio of the radiative energy loss for positrons to that for electrons obeys a simple scaling law, being expressible fairly accurately as a function only of the quantity T 1 /Z 2 . This scaling is exact in the case of the point-Coulomb potential, both for classical bremsstrahlung and for the nonrelativistic dipole Sommerfeld formula. Bremsstrahlung from atoms in hot dense plasmas were also studied describing the atomic potentials by the temperature-and-density dependent Thomas-Fermi mode. Gaunt factors were obtained with the relativistic partial-wave method for atoms in plasmas of various densities and temperatures

  14. FAO and atomic energy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-07-15

    During the past six years FAO has become more engaged in work concerned with atomic energy. In 1957 it established an Atomic Energy Branch. The new forces and new tools which have become available for use in the fight against poverty, disease and malnutrition can be of the greatest assistance in FAO's work in nearly all phases of the production, storage and distribution of food and other agricultural products. The Organization promotes their use to improve the standards of feeding, clothing and housing throughout the world. Another side of work related to atomic energy is concerned with combating contamination from the use of atomic energy for power production and other purposes. This raises considerable problems for food and agriculture, so that FAO also has a responsibility for assisting Governments in safeguarding their food and food-producing resources from contamination. FAO is essentially concerned with fostering wider knowledge of the many contributions that atomic science can make to agriculture, forestry, fisheries and nutrition. It is also concerned in assisting governments to establish sound programmes for applying atomic science in food and agriculture. One way of spreading such knowledge is through the publication of documents and reports

  15. Atomic clocks for geodesy

    Science.gov (United States)

    Mehlstäubler, Tanja E.; Grosche, Gesine; Lisdat, Christian; Schmidt, Piet O.; Denker, Heiner

    2018-06-01

    We review experimental progress on optical atomic clocks and frequency transfer, and consider the prospects of using these technologies for geodetic measurements. Today, optical atomic frequency standards have reached relative frequency inaccuracies below 10‑17, opening new fields of fundamental and applied research. The dependence of atomic frequencies on the gravitational potential makes atomic clocks ideal candidates for the search for deviations in the predictions of Einstein’s general relativity, tests of modern unifying theories and the development of new gravity field sensors. In this review, we introduce the concepts of optical atomic clocks and present the status of international clock development and comparison. Besides further improvement in stability and accuracy of today’s best clocks, a large effort is put into increasing the reliability and technological readiness for applications outside of specialized laboratories with compact, portable devices. With relative frequency uncertainties of 10‑18, comparisons of optical frequency standards are foreseen to contribute together with satellite and terrestrial data to the precise determination of fundamental height reference systems in geodesy with a resolution at the cm-level. The long-term stability of atomic standards will deliver excellent long-term height references for geodetic measurements and for the modelling and understanding of our Earth.

  16. FAO and atomic energy

    International Nuclear Information System (INIS)

    1960-01-01

    During the past six years FAO has become more engaged in work concerned with atomic energy. In 1957 it established an Atomic Energy Branch. The new forces and new tools which have become available for use in the fight against poverty, disease and malnutrition can be of the greatest assistance in FAO's work in nearly all phases of the production, storage and distribution of food and other agricultural products. The Organization promotes their use to improve the standards of feeding, clothing and housing throughout the world. Another side of work related to atomic energy is concerned with combating contamination from the use of atomic energy for power production and other purposes. This raises considerable problems for food and agriculture, so that FAO also has a responsibility for assisting Governments in safeguarding their food and food-producing resources from contamination. FAO is essentially concerned with fostering wider knowledge of the many contributions that atomic science can make to agriculture, forestry, fisheries and nutrition. It is also concerned in assisting governments to establish sound programmes for applying atomic science in food and agriculture. One way of spreading such knowledge is through the publication of documents and reports

  17. Atomic bomb and leukemia

    International Nuclear Information System (INIS)

    Ichimaru, M.; Tomonaga, M.; Amenomori, T.; Matsuo, T.

    1991-01-01

    Characteristic features of the leukemia among atomic bomb survivors were studied. Dose estimates of atomic bomb radiation were based on T65D, but the new dosimetry system DS86 was used for some analyses. The ratio of a single leukemia type to all leukemias was highest for chronic myelogenous leukemia (CML) in Hiroshima, and the occurrence of CML was thought to be most characteristic to atomic bomb radiation induced leukemia. The threshold of CML occurrence in Hiroshima is likely to be between 0.5∼0.09 Gy. However, the threshold of acute leukemia appears to be nearly 1 Gy. In the distribution of acute myeloid leukemia (AML) subtypes by French-American-British classification, there was no M3 case in 1 Gy or more group, although several atypical AML cases of survivors were observed. Although aplastic anemia has not increased as a late effect of the atomic bomb radiation exposure, many atypical leukemia or other myeloproliferative diseases who had been diagnosed as aplastic anemia or its related diseases have been experienced among atomic bomb survivors. Chromosome study was conducted using colony forming cells induced by hemopoietic stem cells of peripheral blood of proximal survivors. Same chromosome aberrations were observed in colony forming cells and peripheral T-cells in several atomic bomb survivors. (author)

  18. Toward the Atomic-Level Mass Analysis of Biomolecules by the Scanning Atom Probe.

    Science.gov (United States)

    Nishikawa, Osamu; Taniguchi, Masahiro

    2017-04-01

    In 1994, a new type of atom probe instrument, named the scanning atom probe (SAP), was proposed. The unique feature of the SAP is the introduction of a small extraction electrode, which scans over a specimen surface and confines the high field, required for field evaporation of surface atoms in a small space, between the specimen and the electrode. Thus, the SAP does not require a sharp specimen tip. This indicates that the SAP can mass analyze the specimens which are difficult to form in a sharp tip, such as organic materials and biomolecules. Clean single wall carbon nanotubes (CNT), made by high-pressure carbon monoxide process are found to be the best substrates for biomolecules. Various amino acids and dipeptide biomolecules were successfully mass analyzed, revealing characteristic clusters formed by strongly bound atoms in the specimens. The mass analysis indicates that SAP analysis of biomolecules is not only qualitative, but also quantitative.

  19. Atomic phenomena in dense plasmas

    International Nuclear Information System (INIS)

    Weisheit, J.C.

    1981-03-01

    The following chapters are included: (1) the plasma environment, (2) perturbations of atomic structure, (3) perturbations of atomic collisions, (4) formation of spectral lines, and (5) dielectronic recombination

  20. General active space commutator-based coupled cluster theory of general excitation rank for electronically excited states: implementation and application to ScH.

    Science.gov (United States)

    Hubert, Mickaël; Olsen, Jeppe; Loras, Jessica; Fleig, Timo

    2013-11-21

    We present a new implementation of general excitation rank coupled cluster theory for electronically excited states based on the single-reference multi-reference formalism. The method may include active-space selected and/or general higher excitations by means of the general active space concept. It may employ molecular integrals over the four-component Lévy-Leblond Hamiltonian or the relativistic spin-orbit-free four-component Hamiltonian of Dyall. In an initial application to ground- and excited states of the scandium monohydride molecule we report spectroscopic constants using basis sets of up to quadruple-zeta quality and up to full iterative triple excitations in the cluster operators. Effects due to spin-orbit interaction are evaluated using two-component multi-reference configuration interaction for assessing the accuracy of the coupled cluster results.

  1. Polarization measurement of atomic hydrogen beam spin-exchanged with optically oriented sodium atoms

    International Nuclear Information System (INIS)

    Ueno, Akira; Ogura, Kouichi; Wakuta, Yoshihisa; Kumabe, Isao

    1988-01-01

    The spin-exchange reaction between hydrogen atoms and optically oriented sodium atoms was used to produce a polarized atomic hydrogen beam. The electron-spin polarization of the atomic hydrogen beam, which underwent the spin-exchange reaction with the optically oriented sodium atoms, was measured. A beam polarization of -(8.0±0.6)% was obtained when the thickness and polarization of the sodium target were (5.78±0.23)x10 13 atoms/cm 2 and -(39.6±1.6)%, respectively. The value of the spin-exchange cross section in the forward scattering direction, whose scattering angle in the laboratory system was less than 1.0 0 , was obtained from the experimental results as Δσ ex =(3.39±0.34)x10 -15 cm 2 . This value is almost seven times larger than the theoretical value calculated from the Na-H potential. The potential was computed quantum mechanically in the space of the appropriate wave functions of the hydrogen and the sodium atoms. (orig./HSI)

  2. An atomic model of the Big Bang

    Science.gov (United States)

    Lasukov, V. V.

    2013-03-01

    An atomic model of the Big Bang has been developed on the basis of quantum geometrodynamics with a nonzero Hamiltonian and on the concept of gravitation developed by Logunov asymptotically combined with the Gliner's idea of a material interpretation of the cosmological constant. The Lemaître primordial atom in superpace-time, whose spatial coordinate is the so-called scaling factor of the Logunov metric of the effective Riemann space, acts as the Big Bang model. The primordial atom in superspace-time corresponds to spatialtime structures(spheres, lines, and surfaces of a level) of the Minkowski spacetime real within the Logunov gravitation theory, the foregoing structures being filled with a scalar field with a negative density of potential energy.

  3. Schroedinger--Dirac spaces of entire functions

    International Nuclear Information System (INIS)

    De Branges, L.

    1977-01-01

    A study is made of some Hilbert spaces of entire function which appear in the quantum mechanical theory of the hydrogen atoms. These spaces are examples in the theory of Hilbert spaces whose elements are entire functions and which have certain given properties. 1 reference

  4. The relation between the (N) and (N-1) electrons atomic ground state

    International Nuclear Information System (INIS)

    Briet, P.

    1984-05-01

    The relation between the ground state of an N and (N-1) electrons atomic system are studied. We show that in some directions of the configuration space, the ratio of the N electrons atomic ground state to the one particle density is asymptotically equivalent to the (N-1) electrons atomic ground state

  5. Direct observation of atoms on surfaces by scanning tunnelling microscopy

    International Nuclear Information System (INIS)

    Baldeschwieler, J.D.

    1989-01-01

    The scanning tunnelling microscope is a non-destructive means of achieving atomic level resolution of crystal surfaces in real space to elucidate surface structures, electronic properties and chemical composition. Scanning tunnelling microscope is a powerful, real space surface structure probe complementary to other techniques such as x-ray diffraction. 21 refs., 8 figs

  6. Dirac equation, hydrogen atom spectrum and the Lamb shift in ...

    Indian Academy of Sciences (India)

    2017-04-12

    Apr 12, 2017 ... Abstract. We derive the relativistic Hamiltonian of hydrogen atom in dynamical non-commutative spaces. (DNCS or τ-space). Using this Hamiltonian we calculate the energy shift of the ground state as well the 2P1/2, 2S1/2 levels. In all the cases, the energy shift depends on the dynamical non-commutative ...

  7. Hydrogen atom spectrum and the Lamb shift in noncommutative QED

    International Nuclear Information System (INIS)

    Chaichian, M. . Helsinki Institute of Physics, Helsinki; Tureanu, A. . Helsinki Institute of Physics, Helsinki; FI)

    2000-10-01

    We have calculated the energy levels of the hydrogen atom and as well the Lamb shift within the noncommutative quantum electrodynamics theory. The results show deviations from the usual QED both on the classical and on the quantum levels. On both levels, the deviations depend on the parameter of space/space noncommutativity. (author)

  8. Model for pairing phase transition in atomic nuclei

    International Nuclear Information System (INIS)

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

    2002-01-01

    A model is developed which allows the investigation and classification of the pairing phase transition in atomic nuclei. The regions of the parameter space are discussed for which a pairing phase transition can be observed. The model parameters include number of particles, attenuation of pairing correlations with increasing seniority, single-particle level spacing, and pairing gap parameter

  9. Radiation protection in space

    Energy Technology Data Exchange (ETDEWEB)

    Blakely, E.A. [Lawrence Berkeley Lab., CA (United States); Fry, R.J.M. [Oak Ridge National Lab., TN (United States)

    1995-02-01

    The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in the present state of knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared to previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

  10. Radiation protection in space

    International Nuclear Information System (INIS)

    Blakely, E.A.; Fry, R.J.M.

    1995-01-01

    The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in the present state of knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared to previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space

  11. UNESCO and atomic energy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-01-15

    Atomic energy has been of particular concern to UNESCO virtually since the founding of this United Nations agency with the mission of promoting the advancement of science along with education and culture. UNESCO has been involved in the scientific aspects of nuclear physics - notably prior to the creation of the International Atomic Energy Agency - but it has also focussed its attention upon the educational and cultural problems of the atomic age. UNESCO's sphere of action was laid down by its 1954 General Conference which authorized its Director-General to extend full co-operation to the United Nations in atomic energy matters, with special reference to 'the urgent study of technical questions such as those involved in the effects of radioactivity on life in general, and to the dissemination of objective information concerning all aspects of the peaceful utilization of atomic energy; to study, and if necessary, to propose measures of international scope to facilitate the use of radioisotopes in research and industry'. UNESCO's first action under this resolution was to call a meeting of a committee of experts from twelve nations to study the establishment of a system of standards and regulations for the preparation, distribution, transport and utilization of radioactive isotopes and tracer molecules

  12. Precision measurements with atom interferometry

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Schlippert, Dennis; Ertmer, Wolfgang; Rasel, Ernst M.

    2017-04-01

    Interferometry with matter waves enables precise measurements of rotations, accelerations, and differential accelerations [1-5]. This is exploited for determining fundamental constants [2], in fundamental science as e.g. testing the universality of free fall [3], and is applied for gravimetry [4], and gravity gradiometry [2,5]. At the Institut für Quantenoptik in Hannover, different approaches are pursued. A large scale device is designed and currently being set up to investigate the gain in precision for gravimetry, gradiometry, and fundamental tests on large baselines [6]. For field applications, a compact and transportable device is being developed. Its key feature is an atom chip source providing a collimated high flux of atoms which is expected to mitigate systematic uncertainties [7,8]. The atom chip technology and miniaturization benefits from microgravity experiments in the drop tower in Bremen and sounding rocket experiments [8,9] which act as pathfinders for space borne operation [10]. This contribution will report about our recent results. The presented work is supported by the CRC 1227 DQ-mat, the CRC 1128 geo-Q, the RTG 1729, the QUEST-LFS, and by the German Space Agency (DLR) with funds provided by the Federal Ministry of Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under Grant No. DLR 50WM1552-1557. [1] P. Berg et al., Phys. Rev. Lett., 114, 063002, 2015; I. Dutta et al., Phys. Rev. Lett., 116, 183003, 2016. [2] J. B. Fixler et al., Science 315, 74 (2007); G. Rosi et al., Nature 510, 518, 2014. [3] D. Schlippert et al., Phys. Rev. Lett., 112, 203002, 2014. [4] A. Peters et al., Nature 400, 849, 1999; A. Louchet-Chauvet et al., New J. Phys. 13, 065026, 2011; C. Freier et al., J. of Phys.: Conf. Series 723, 012050, 2016. [5] J. M. McGuirk et al., Phys. Rev. A 65, 033608, 2002; P. Asenbaum et al., arXiv:1610.03832. [6] J. Hartwig et al., New J. Phys. 17, 035011, 2015. [7] H. Ahlers et al., Phys. Rev. Lett. 116, 173601

  13. Accelerators for atomic energy research

    International Nuclear Information System (INIS)

    Shibata, Tokushi

    1999-01-01

    The research and educational activities accomplished using accelerators for atomic energy research were studied. The studied items are research subjects, facility operation, the number of master theses and doctor theses on atomic energy research using accelerators and the future role of accelerators in atomic energy research. The strategy for promotion of the accelerator facility for atomic energy research is discussed. (author)

  14. Atomic nucleus and elementary particles

    International Nuclear Information System (INIS)

    Zakrzewski, J.

    1976-01-01

    Negatively charged leptons and hadrons can be incorporated into atomic shells forming exotic atoms. Nucleon resonances and Λ hyperons can be considered as constituents of atomic nuclei. Information derived from studies of such exotic systems enriches our knowledge of both the interactions of elementary particles and of the structure of atomic nuclei. (author)

  15. Compilation of data from hadronic atoms

    International Nuclear Information System (INIS)

    Poth, H.

    1979-01-01

    This compilation is a survey of the existing data of hadronic atoms (pionic-atoms, kaonic-atoms, antiprotonic-atoms, sigmonic-atoms). It collects measurements of the energies, intensities and line width of X-rays from hadronic atoms. Averaged values for each hadronic atom are given and the data are summarized. The listing contains data on 58 pionic-atoms, on 54 kaonic-atoms, on 23 antiprotonic-atoms and on 20 sigmonic-atoms. (orig./HB) [de

  16. CP violation in atoms

    International Nuclear Information System (INIS)

    Barr, S.M.

    1992-01-01

    Electric dipole moments of large atoms are an excellent tool to search for CP violation beyond the Standard Model. These tell us about the electron EDM but also about CP-violating electron-nucleon dimension-6 operators that arise from Higgs-exchange. Rapid strides are being made in searches for atomic EDMs. Limits on the electron EDM approaching the values which would be expected from Higgs-exchange mediated CP violation have been achieved. It is pointed out that in this same kind of model if tan β is large the effects in atoms of the dimension-6 e - n operators may outweigh the effect of the electron EDM. (author) 21 refs

  17. US Atomic Energy Law

    International Nuclear Information System (INIS)

    1981-01-01

    This is a new volume follows in the series supplementing the volumes 11 and 12 published in 1965 and 1966, updating the collection of Federal Acts and Executive Orders of the President of the United States of America relating to atomic energy legislation. Since the publication of volumes 11 and 12, the US Atomic Energy Act of 1954 alone has been amended 25 times, mainly as a consequence of by the Nuclear Non-Proliferation Act and the Uranium Mill Tailings Radiation Control Act, both of 1978. The Atomic Energy Act of 1954 is supplemented by a selection of the most important Federal Acts, Executive Orders of the President and Resolutions of the Congress. (orig./HSCH) [de

  18. Atomic profits, no thanks

    International Nuclear Information System (INIS)

    Bartels, W.; Dietrich, K.; Moeller, H.; Speier, C.

    1980-01-01

    The authors deal with the following topics: The secret of nuclear energy; the atom programmes of Bonn; on some arguments of the present nuclear energy discussion; how socialist countries solve the problems of nuclear energy. From the socialist point of view they discuss sociological, ideological and moral reasons for a peaceful utilization of nuclear energy. Nevertheless they refuse Bonn's atom programme because the high finance's interests concerning profit and power make it a danger. The biggest danger is said to lie in the creation of a plutonium-industry and the militaristic abuse which would be connected with it. The socialist way of utilizing atomic energy is seen by them as a way with a high feeling of responsibility towards all people and towards a guaranteed energy supply. (HSCH) [de

  19. Controlling the atom

    International Nuclear Information System (INIS)

    Mazuzan, G.T.; Walker, J.S.

    1984-01-01

    The authors trace the early history of nuclear power regulation in the US. Focusing on the Atomic Energy Commission, they describe the role of other groups that figured in the development of regulatory policies, including the Congressional Joint Committee on Atomic Energy, other federal agencies, state governments, the nuclear industry, and scientific organizations. They consider changes in public perceptions of and attitudes toward atomic energy and the dangers of radiation exposure. The basic purpose of the book is to provide the Nuclear Regulatory Commission and the general public with information on the historical antecedents and background of regulatory issues so that there will be continuity in policy decisions. The book concludes with an annotated bibliography of selected references. 19 figures

  20. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  1. Thermal effects from modified endodontic laser tips used in the apical third of root canals with erbium-doped yttrium aluminium garnet and erbium, chromium-doped yttrium scandium gallium garnet lasers.

    Science.gov (United States)

    George, Roy; Walsh, Laurence J

    2010-04-01

    To evaluate the temperature changes occurring on the apical third of root surfaces when erbium-doped yttrium aluminium garnet (Er:YAG) and erbium, chromium-doped yttrium scandium gallium garnet (Er,Cr:YSGG) laser energy was delivered with a tube etched, laterally emitting conical tip and a conventional bare design optical fiber tip. Thermal effects of root canal laser treatments on periodontal ligament cells and alveolar bone are of concern in terms of safety. A total of 64 single-rooted extracted teeth were prepared 1 mm short of the working length using rotary nickel-titanium Pro-Taper files to an apical size corresponding to a F5 Pro-Taper instrument. A thermocouple located 2 mm from the apex was used to record temperature changes arising from delivery of laser energy through laterally emitting conical tips or plain tips, using an Er:YAG or Er,Cr:YSGG laser. For the Er:YAG and Er,Cr:YSGG systems, conical fibers showed greater lateral emissions (452 + 69% and 443 + 64%) and corresponding lower forward emissions (48 + 5% and 49 + 5%) than conventional plain-fiber tips. All four combinations of laser system and fiber design elicited temperature increases less than 2.5 degrees C during lasing. The use of water irrigation attenuated completely the thermal effects of individual lasing cycles. Laterally emitting conical fiber tips can be used safely under defined conditions for intracanal irradiation without harmful thermal effects on the periodontal apparatus.

  2. A novel spacetime concept for describing electronic motion within a helium atom

    OpenAIRE

    Xu, Kunming

    2007-01-01

    Euclidean space and linear algebra do not characterize dynamic electronic orbitals satisfactorily for even the motion of both electrons in an inert helium atom cannot be defined in reasonable details. Here the author puts forward a novel two-dimensional spacetime model from scratch in the context of defining both electrons in a helium atom. Space and time are treated as two orthogonal, symmetric and complementary quantities under the atomic spacetime. Electronic motion observed the rule of di...

  3. Atoms in Slovakia

    International Nuclear Information System (INIS)

    Danis, D.; Feik, K.; Florek, M.; Kmosena, J.; Chrapan, J.; Morovic, M.; Slugen, V.; Seliga, M.; Valovic, J.

    2006-01-01

    In this book the history of development of using of nuclear energy in the Slovak Republic as well as in the Czechoslovakia (before 1993 year) is presented. The aim of the book is to preserve the memory of the period when the creation and development of nuclear physics, technology, nuclear medicine, radioecology and energetics in Slovakia occurred - as witnessed by people who experienced this period and to adapt it to future generations. The Editorial board of the SNUS collected the views of 60 contributors and distinguished workers - Slovakian experts in nuclear science, education and technology. Calling upon a wide spectrum of experts ensured an objective historical description of the period. A huge amount of subjective views on recent decades were collected and supported by a wealth of photographic documentation. This created a synthesised reflection on the history of the 'atoms' in Slovakia. The book contains 15 tables, 192 black and white and 119 colour pictures from around the world and from places involved in the compilation of the study and with the study of atomic science in Slovakia. The main chapters are as follows: Atoms in the world, Atoms in Slovakia, Atoms in the educational system, Atoms in health services (Radiology, Nuclear medicine, Radiation protection, the Cyclotron centre of the Slovak Republic), Radioecology, Other applications of irradiation, Nuclear energetics (Electric energy in the second half of the 20 th century, NPP Bohunice, NPP Mochovce, the back-end of Nuclear energetics, Big names in Nuclear energetics in Slovakia), Chronology and an Appendix entitled 'Slovak companies in nuclear energetics'

  4. Positron-atom collisions

    International Nuclear Information System (INIS)

    Drachman, R.J.

    1984-01-01

    The past decade has seen the field of positron-atom collisions mature into an important sub-field of atomic physics. Increasingly intense positron sources are leading towards a situation in which electron and positron collision experiments will be on almost an equal footing, challenging theory to analyze their similarities and differences. The author reviews the advances made in theory, including dispersion theory, resonances, and inelastic processes. A survey of experimental progress and a brief discussion of astrophysical positronics is also included. (Auth.)

  5. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  6. Optically pumped atoms

    CERN Document Server

    Happer, William; Walker, Thad

    2010-01-01

    Covering the most important knowledge on optical pumping of atoms, this ready reference is backed by numerous examples of modelling computation for optical pumped systems. The authors show for the first time that modern scientific computing software makes it practical to analyze the full, multilevel system of optically pumped atoms. To make the discussion less abstract, the authors have illustrated key points with sections of MATLAB codes. To make most effective use of contemporary mathematical software, it is especially useful to analyze optical pumping situations in the Liouville spa

  7. Atomic cluster collisions

    Science.gov (United States)

    Korol, Andrey V.; Solov'yov, Andrey

    2013-01-01

    Atomic cluster collisions are a field of rapidly emerging research interest by both experimentalists and theorists. The international symposium on atomic cluster collisions (ISSAC) is the premier forum to present cutting-edge research in this field. It was established in 2003 and the most recent conference was held in Berlin, Germany in July of 2011. This Topical Issue presents original research results from some of the participants, who attended this conference. This issues specifically focuses on two research areas, namely Clusters and Fullerenes in External Fields and Nanoscale Insights in Radiation Biodamage.

  8. Pulsed atomic soliton laser

    International Nuclear Information System (INIS)

    Carr, L.D.; Brand, J.

    2004-01-01

    It is shown that simultaneously changing the scattering length of an elongated, harmonically trapped Bose-Einstein condensate from positive to negative and inverting the axial portion of the trap, so that it becomes expulsive, results in a train of self-coherent solitonic pulses. Each pulse is itself a nondispersive attractive Bose-Einstein condensate that rapidly self-cools. The axial trap functions as a waveguide. The solitons can be made robustly stable with the right choice of trap geometry, number of atoms, and interaction strength. Theoretical and numerical evidence suggests that such a pulsed atomic soliton laser can be made in present experiments

  9. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  10. STMD Laser Lifetest Program Space Gradiometer

    Data.gov (United States)

    National Aeronautics and Space Administration — Design and initiate lifetest activities on laser transmitter for the Cold Atom Gravity Gradiometer (CAGG) with funding from NASA STMD.This proposed task is to...

  11. Atomic collisions related to atomic laser isotope separation

    International Nuclear Information System (INIS)

    Shibata, Takemasa

    1995-01-01

    Atomic collisions are important in various places in atomic vapor laser isotope separation (AVLIS). At a vaporization zone, many atomic collisions due to high density have influence on the atomic beam characteristics such as velocity distribution and metastable states' populations at a separation zone. In the separation zone, a symmetric charge transfer between the produced ions and the neutral atoms may degrade selectivity. We have measured atomic excitation temperatures of atomic beams and symmetric charge transfer cross sections for gadolinium and neodymium. Gadolinium and neodymium are both lanthanides. Nevertheless, results for gadolinium and neodymium are very different. The gadolinium atom has one 5d electron and neodymium atom has no 5d electron. It is considered that the differences are due to existence of 5d electron. (author)

  12. Spatially resolved photoionization of ultracold atoms on an atom chip

    International Nuclear Information System (INIS)

    Kraft, S.; Guenther, A.; Fortagh, J.; Zimmermann, C.

    2007-01-01

    We report on photoionization of ultracold magnetically trapped Rb atoms on an atom chip. The atoms are trapped at 5 μK in a strongly anisotropic trap. Through a hole in the chip with a diameter of 150 μm, two laser beams are focused onto a fraction of the atomic cloud. A first laser beam with a wavelength of 778 nm excites the atoms via a two-photon transition to the 5D level. With a fiber laser at 1080 nm the excited atoms are photoionized. Ionization leads to depletion of the atomic density distribution observed by absorption imaging. The resonant ionization spectrum is reported. The setup used in this experiment is suitable not only to investigate mixtures of Bose-Einstein condensates and ions but also for single-atom detection on an atom chip

  13. Atomic physics through astrophysics

    International Nuclear Information System (INIS)

    Dalgarno, A.

    1987-01-01

    Astronomical environments encompass an extreme range of physical conditions of temperature, density, pressure and radiation fields and unusual situations abound. In this lecture, the author describes some of the objects found in the Universe and discussed the atomic processes that occur. 45 references, 8 figures

  14. Rutherford-Bohr atom

    Science.gov (United States)

    Heilbron, J. L.

    1981-03-01

    Bohr used to introduce his attempts to explain clearly the principles of the quantum theory of the atom with an historical sketch, beginning invariably with the nuclear model proposed by Rutherford. That was sound pedagogy but bad history. The Rutherford-Bohr atom stands in the middle of a line of work initiated by J.J. Thomson and concluded by the invention of quantum mechanics. Thompson's program derived its inspiration from the peculiar emphasis on models characteristic of British physics of the 19th century. Rutherford's atom was a late product of the goals and conceptions of Victorian science. Bohr's modifications, although ultimately fatal to Thomson's program, initially gave further impetus to it. In the early 1920s the most promising approach to an adequate theory of the atom appeared to be the literal and detailed elaboration of the classical mechanics of multiply periodic orbits. The approach succeeded, demonstrating in an unexpected way the force of an argument often advanced by Thomson: because a mechanical model is richer in implications than the considerations for which it was advanced, it can suggest new directions of research that may lead to important discoveries.

  15. Deep diode atomic battery

    International Nuclear Information System (INIS)

    Anthony, T.R.; Cline, H.E.

    1977-01-01

    A deep diode atomic battery is made from a bulk semiconductor crystal containing three-dimensional arrays of columnar and lamellar P-N junctions. The battery is powered by gamma rays and x-ray emission from a radioactive source embedded in the interior of the semiconductor crystal

  16. Atoms in Astronomy.

    Science.gov (United States)

    Blanchard, Paul A.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. A Basic Topics section discusses atomic structure, emphasizing states of matter at high temperature and spectroscopic analysis of light from the stars. A section…

  17. Atomic energy and you

    International Nuclear Information System (INIS)

    1975-01-01

    The film discusses the peaceful applications of atomic energy in agriculture, engineering, industry and medicine. Shows exploration, prospecting and mining of uraninum ores at Larap, Camarines Norte and the study of geographical conditions of the site for the proposed Nuclear Power Plant in Bataan

  18. Discovery and the atom

    International Nuclear Information System (INIS)

    1989-01-01

    ''Discovery and the Atom'' tells the story of the founding of nuclear physics. This programme looks at nuclear physics up to the discovery of the neutron in 1932. Animation explains the science of the classic experiments, such as the scattering of alpha particles by Rutherford and the discovery of the nucleus. Archive film shows the people: Lord Rutherford, James Chadwick, Marie Curie. (author)

  19. Atomically resolved tissue integration.

    Science.gov (United States)

    Karlsson, Johan; Sundell, Gustav; Thuvander, Mattias; Andersson, Martin

    2014-08-13

    In the field of biomedical technology, a critical aspect is the ability to control and understand the integration of an implantable device in living tissue. Despite the technical advances in the development of biomaterials, the elaborate interplay encompassing materials science and biology on the atomic level is not very well understood. Within implantology, anchoring a biomaterial device into bone tissue is termed osseointegration. In the most accepted theory, osseointegration is defined as an interfacial bonding between implant and bone; however, there is lack of experimental evidence to confirm this. Here we show that atom probe tomography can be used to study the implant-tissue interaction, allowing for three-dimensional atomic mapping of the interface region. Interestingly, our analyses demonstrated that direct contact between Ca atoms and the implanted titanium oxide surface is formed without the presence of a protein interlayer, which means that a pure inorganic interface is created, hence giving experimental support to the current theory of osseointegration. We foresee that this result will be of importance in the development of future biomaterials as well as in the design of in vitro evaluation techniques.

  20. Atomic transport properties

    International Nuclear Information System (INIS)

    Freyss, M.

    2015-01-01

    As presented in the first chapter of this book, atomic transport properties govern a large panel of nuclear fuel properties, from its microstructure after fabrication to its behaviour under irradiation: grain growth, oxidation, fission product release, gas bubble nucleation. The modelling of the atomic transport properties is therefore the key to understanding and predicting the material behaviour under irradiation or in storage conditions. In particular, it is noteworthy that many modelling techniques within the so-called multi-scale modelling scheme of materials make use of atomic transport data as input parameters: activation energies of diffusion, diffusion coefficients, diffusion mechanisms, all of which are then required to be known accurately. Modelling approaches that are readily used or which could be used to determine atomic transport properties of nuclear materials are reviewed here. They comprise, on the one hand, static atomistic calculations, in which the migration mechanism is fixed and the corresponding migration energy barrier is calculated, and, on the other hand, molecular dynamics calculations and kinetic Monte-Carlo simulations, for which the time evolution of the system is explicitly calculated. (author)

  1. Experimental atomic physics

    International Nuclear Information System (INIS)

    Sellin, I.A.; Elston, S.B.; Forester, J.P.; Liao, K.H.; Pegg, D.J.; Peterson, R.S.; Thoe, R.S.; Hayden, H.C.; Griffin, P.M.

    1976-01-01

    The atomic structure and collision phenomena of highly stripped ions in the range Z = 6 to 35 were studied. Charge-transfer and multiple-electron-loss cross sections were determined. Absolute x-ray-production cross sections for incident heavy ions were measured. 10 figures, 1 table

  2. Transition probabilities for atoms

    International Nuclear Information System (INIS)

    Kim, Y.K.

    1980-01-01

    Current status of advanced theoretical methods for transition probabilities for atoms and ions is discussed. An experiment on the f values of the resonance transitions of the Kr and Xe isoelectronic sequences is suggested as a test for the theoretical methods

  3. Ludwig Boltzmann: Atomic genius

    Energy Technology Data Exchange (ETDEWEB)

    Cercignani, C. [Department of Mathematics, Politecnico di Milano (Italy)]. E-mail: carcer@mate.polimi.it

    2006-09-15

    On the centenary of the death of Ludwig Boltzmann, Carlo Cercignani examines the immense contributions of the man who pioneered our understanding of the atomic nature of matter. The man who first gave a convincing explanation of the irreversibility of the macroscopic world and the symmetry of the laws of physics was the Austrian physicist Ludwig Boltzmann, who tragically committed suicide 100 years ago this month. One of the key figures in the development of the atomic theory of matter, Boltzmann's fame will be forever linked to two fundamental contributions to science. The first was his interpretation of 'entropy' as a mathematically well-defined measure of the disorder of atoms. The second was his derivation of what is now known as the Boltzmann equation, which describes the statistical properties of a gas as made up of molecules. The equation, which described for the first time how a probability can evolve with time, allowed Boltzmann to explain why macroscopic phenomena are irreversible. The key point is that while microscopic objects like atoms can behave reversibly, we never see broken coffee cups reforming because it would involve a long series of highly improbable interactions - and not because it is forbidden by the laws of physics. (U.K.)

  4. Observational Evidence for Atoms.

    Science.gov (United States)

    Jones, Edwin R., Jr.; Childers, Richard L.

    1984-01-01

    Discusses the development of the concept of atomicity and some of the many which can be used to establish its validity. Chemical evidence, evidence from crystals, Faraday's law of electrolysis, and Avogadro's number are among the areas which show how the concept originally developed from a purely philosophical idea. (JN)

  5. Coherent atomic spectroscopy

    International Nuclear Information System (INIS)

    Garton, W.R.S.

    1988-01-01

    The Argonne Spectroscopy Laboratory, initiated and advanced over several decades by F.S. Tomkins and M. Fred, has been a major international facility. A range of collaborative work in atomic spectroscopy is selected to illustrate advances in experimental physics which have been made possible by combination of the talents of Tomkins and Fred with the unique facilities of the Argonne Laboratory. (orig.)

  6. Spectra of alkali atoms

    International Nuclear Information System (INIS)

    Santoso, Budi; Arumbinang, Haryono.

    1981-01-01

    Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

  7. Atomic Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1970-01-01

    This booklet tells how scientists observe the particles and electromagnetic radiation that emerges from an atomic nucleus. The equipment used falls into two general categories: counters which count each particle as it passes by, and track detectors, which make a photographic record of the particle's track.

  8. Atomic Physics 16: Sixteenth International Conference on Atomic Physics. Proceedings

    International Nuclear Information System (INIS)

    Baylis, W.E.; Drake, G.W.

    1999-01-01

    These proceedings represent papers presented at the 16th International Conference on Atomic Physics held in Windsor, Ontario, Canada, in August, 1998. The topics discussed included a wide array of subjects in atomic physics such as atom holography, alignment in atomic collisions, coulomb-interacting particles, muon experiments, x-rays from comets, atomic electron collisions in intense laser fields, spectroscopy of trapped ions, and Bose-Einstein condensates. This conference represents the single most important meeting world wide on fundamental advances in atomic physics. There were 30 papers presented at the conference,out of which 4 have been abstracted for the Energy, Science and Technology database

  9. Atomic bomb injury: radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, C L; Cronkite, E P; Le Roy, G V; Warren, S

    1959-01-01

    This document contains 3 reports. In the first report, the clinical diagnosis and treatment of radiation syndrome in survivors of the atomic explosions in Hiroshima and Nagasaki are described. The syndrome of acute radiation injury is applied to the symptom complex, or diseased state, which results from exposure of the whole body to the initial nuclear radiation of an atomic bomb. It is applied to injuries of the skin and subcutaneous tissues resulting from x-radiation or from contact with radioactive material. Internal radiation injury may result from the selective deposition, such as in bone or thyroid, of radioactive material that has been inhaled or absorbed through the gastrointestinal tract or wounds. Radiation syndrome is classified as very severe, severe, and mild. In the second report, a brief discussion is presented on the question of genetic effects in atomic bomb survivors in Hiroshima and Nagasaki. In the third report, a study was carried out on 205 4-1/2 year old children who had been exposed to the atomic bomb blast during the first half of intra-uterine life. Correlation between head size and mental development of the child with distance from the hypocenter, symptoms of radiation effect and type of shielding of the mother is discussed. The conclusion drawn from the present study is that central nervous system defects can be produced in the fetus by atomic bomb radiation, provided that exposure occurs within approximately 1200 meters of the hypocenter and that no effective shielding, such as concrete, protects the fetus from direct irradiation.

  10. Trapped atoms along nanophotonic resonators

    Science.gov (United States)

    Fields, Brian; Kim, May; Chang, Tzu-Han; Hung, Chen-Lung

    2017-04-01

    Many-body systems subject to long-range interactions have remained a very challenging topic experimentally. Ultracold atoms trapped in extreme proximity to the surface of nanophotonic structures provides a dynamic system combining the strong atom-atom interactions mediated by guided mode photons with the exquisite control implemented with trapped atom systems. The hybrid system promises pair-wise tunability of long-range interactions between atomic pseudo spins, allowing studies of quantum magnetism extending far beyond nearest neighbor interactions. In this talk, we will discuss our current status developing high quality nanophotonic ring resonators, engineered on CMOS compatible optical chips with integrated nanostructures that, in combination with a side illuminating beam, can realize stable atom traps approximately 100nm above the surface. We will report on our progress towards loading arrays of cold atoms near the surface of these structures and studying atom-atom interaction mediated by photons with high cooperativity.

  11. Dynamics of moving interacting atoms in a laser radiation field and optical size resonances

    International Nuclear Information System (INIS)

    Gadomskii, O.N.; Glukhov, A.G.

    2005-01-01

    The forces acting on interacting moving atoms exposed to resonant laser radiation are calculated. It is shown that the forces acting on the atoms include the radiation pressure forces as well as the external and internal bias forces. The dependences of the forces on the atomic spacing, polarization, and laser radiation frequency are given. It is found that the internal bias force associated with the interaction of atomic dipoles via the reemitted field may play an important role in the dynamics of dense atomic ensembles in a light field. It is shown that optical size resonances appear in the system of interacting atoms at frequencies differing substantially from transition frequencies in the spectrum of atoms. It is noted that optical size resonances as well as the Doppler frequency shift in the spectrum of interacting atoms play a significant role in the processes of laser-radiation-controlled motion of the atoms

  12. From Photons to Atoms - The Electromagnetic Nature of Matter

    OpenAIRE

    Funaro, Daniele

    2012-01-01

    Motivated by a revision of the classical equations of electromagnetism that allow for the inclusion of solitary waves in the solution space, the material collected in these notes examine the consequences of adopting the modified model in the description of atomic structures. The possibility of handling "photons" in a deterministic way opens indeed a chance for reviewing the foundations of quantum physics. Atoms and molecules are described as aggregations of nuclei and electrons joined through...

  13. Laser-Cooled Ions and Atoms in a Storage Ring

    International Nuclear Information System (INIS)

    Kleinert, J.; Hannemann, S.; Eike, B.; Eisenbarth, U.; Grieser, M.; Grimm, R.; Gwinner, G.; Karpuk, S.; Saathoff, G.; Schramm, U.; Schwalm, D.; Weidemueller, M.

    2003-01-01

    We review recent experiments at the Heidelberg Test Storage Ring which apply advanced laser cooling techniques to stored ion beams. Very high phase-space densities are achieved by three-dimensional laser cooling of a coasting 9 Be + beam at 7.3 MeV. Laser-cooled, trapped Cs atoms are used as an ultracold precision target for the study of ion-atom interactions with a 74 MeV beam of 12 C 6+ ions.

  14. Ionization of highly excited atoms by atomic particle impact

    International Nuclear Information System (INIS)

    Smirnov, B.M.

    1976-01-01

    The ionization of a highly excited atom by a collision with an atom or molecule is considered. The theory of these processes is presented and compared with experimental data. Cross sections and ionization potential are discussed. 23 refs

  15. Single-atom lasing induced atomic self-trapping

    International Nuclear Information System (INIS)

    Salzburger, T.; Ritsch, H.

    2004-01-01

    We study atomic center of mass motion and field dynamics of a single-atom laser consisting of a single incoherently pumped free atom moving in an optical high-Q resonator. For sufficient pumping, the system starts lasing whenever the atom is close to a field antinode. If the field mode eigenfrequency is larger than the atomic transition frequency, the generated laser light attracts the atom to the field antinode and cools its motion. Using quantum Monte Carlo wave function simulations, we investigate this coupled atom-field dynamics including photon recoil and cavity decay. In the regime of strong coupling, the generated field shows strong nonclassical features like photon antibunching, and the atom is spatially confined and cooled to sub-Doppler temperatures. (author)

  16. Holographic atom imaging from experimental photoelectron angular distribution patterns

    International Nuclear Information System (INIS)

    Terminello, L.J.; Lapiano-Smith, D.A.; Barton, J.J.; Shirley, D.A.

    1993-11-01

    One of the most challenging areas of materials research is the imaging of technologically relevant materials with microscopic and atomic-scale resolution. As part of the development of these methods, near-surface atoms in single crystals were imaged using core-level photoelectron holograms. The angle-dependent electron diffraction patterns that constitute an electron hologram were two-dimensionally transformed to create a three dimensional, real-space image of the neighboring scattering atoms. They have made use of a multiple-wavenumber, phased-summing method to improve the atom imaging capabilities of experimental photoelectron holography using the Cu(001) and Pt(111) prototype systems. These studies are performed to evaluate the potential of holographic atom imaging methods as structural probes of unknown materials

  17. Single-spin addressing in an atomic Mott insulator

    DEFF Research Database (Denmark)

    Weitenberg, Christof; Endres, Manuel; Sherson, Jacob

    2011-01-01

    directly monitored the tunnelling quantum dynamics of single atoms in the lattice prepared along a single line, and observed that our addressing scheme leaves the atoms in the motional ground state. The results should enable studies of entropy transport and the quantum dynamics of spin impurities...... and quantum spin dynamics. Here we demonstrate how such control can be implemented at the most fundamental level of a single spin at a specific site of an optical lattice. Using a tightly focused laser beam together with a microwave field, we were able to flip the spin of individual atoms in a Mott insulator...... with sub-diffraction-limited resolution, well below the lattice spacing. The Mott insulator provided us with a large two-dimensional array of perfectly arranged atoms, in which we created arbitrary spin patterns by sequentially addressing selected lattice sites after freezing out the atom distribution. We...

  18. Neighborhood spaces

    OpenAIRE

    D. C. Kent; Won Keun Min

    2002-01-01

    Neighborhood spaces, pretopological spaces, and closure spaces are topological space generalizations which can be characterized by means of their associated interior (or closure) operators. The category NBD of neighborhood spaces and continuous maps contains PRTOP as a bicoreflective subcategory and CLS as a bireflective subcategory, whereas TOP is bireflectively embedded in PRTOP and bicoreflectively embedded in CLS. Initial and final structures are described in these categories, and it is s...

  19. Hot atom chemistry of monovalent atoms in organic condensed phases

    International Nuclear Information System (INIS)

    Stoecklin, G.

    1975-01-01

    The advantages and disadvantages of hot atom studies in condensed organic phases are considered, and recent advances in condensed phase organic hot atom chemistry of recoil tritium and halogen atoms are discussed. Details are presented of the present status and understanding of liquid phase hot atom chemistry and also that of organic solids. The consequences of the Auger effect in condensed organic systems are also considered. (author)

  20. Absorption imaging of ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Smith, David A.; Aigner, Simon; Hofferberth, Sebastian

    2011-01-01

    Imaging ultracold atomic gases close to surfaces is an important tool for the detailed analysis of experiments carried out using atom chips. We describe the critical factors that need be considered, especially when the imaging beam is purposely reflected from the surface. In particular we present...... methods to measure the atom-surface distance, which is a prerequisite for magnetic field imaging and studies of atom surface-interactions....

  1. The Atomic energy basic law

    International Nuclear Information System (INIS)

    1979-01-01

    The law aims to secure future energy resources, push forward progress of science and advancement of industry for welfare of the mankind and higher standard of national life by helping research, development and utilization of atomic power. Research, development and utilization of atomic power shall be limited to the peaceful purpose with emphasis laid on safety and carried on independently under democratic administration. Basic concepts and terms are defined, such as: atomic power; nuclear fuel material; nuclear raw material; reactor and radiation. The Atomic Energy Commission and the Atomic Energy Safety Commission shall be set up at the Prime Minister's Office deliberately to realize national policy of research, development and utilization of atomic power and manage democratic administration for atomic energy. The Atomic Energy Commission shall plan, consider and decide matters concerning research, development and utilization of atomic energy. The Atomic Energy Safety Commission shall plan, consider and decide issues particularly concerning safety securing among such matters. The Atomic Energy Research Institute shall be founded under the governmental supervision to perform research, experiment and other necessary affairs for development of atomic energy. The Power Reactor and Nuclear Fuel Development Corporation shall be established likewise to develop fast breeding reactor, advanced thermal reactor and nuclear fuel materials. Development of radioactive minerals, control of nuclear fuel materials and reactors and measures for patent and invention concerning atomic energy, etc. are stipulated respectively. (Okada, K.)

  2. Atomic Absorption, Atomic Fluorescence, and Flame Emission Spectrometry.

    Science.gov (United States)

    Horlick, Gary

    1984-01-01

    This review is presented in six sections. Sections focus on literature related to: (1) developments in instrumentation, measurement techniques, and procedures; (2) performance studies of flames and electrothermal atomizers; (3) applications of atomic absorption spectrometry; (4) analytical comparisons; (5) atomic fluorescence spectrometry; and (6)…

  3. Atomic and molecular databases in the context of virtual observatories

    International Nuclear Information System (INIS)

    Dubernet, Marie-Lise; Roueff, Evelyne

    2006-01-01

    Numerical and bibliographic Databases in Atomic and Molecular Physics are essential for both the modelling of various astrophysical media and the interpretation of astrophysical spectra provided by ground or space-based telescopes. We report here on our current project concerning the access to Atomic and Molecular Databases within the Virtual Observatories. This presentation aims at informing people about interoperability matters, in order to put together the efforts which have already started in this domain, to evaluate the needs and requirements of the targeted interrelation between atomic and molecular data bases and VO projects. Collaborations in this domain are welcome. (author)

  4. Atomic Act amended

    International Nuclear Information System (INIS)

    Drabova, D.

    2002-01-01

    In the paper by the chairwoman of the Czech nuclear regulatory authority, the history of Czech nuclear legislation is outlined, the reasons for the amendment of the Atomic Act (Act No. 18/1997) are explained, and the amendments themselves are highlighted. The Act No. 13/2002 of 18 December 2001 is reproduced from the official Collection of Acts of the Czech Republic in the facsimile form. The following acts were thereby amended: Atomic Act No. 18/1997, Metrology Act No. 505/1990, Public Health Protection Act No. 258/2000, and Act No. 2/1969 on the Establishment of Ministries and Other Governmental Agencies of the Czech Republic. (P.A.)

  5. Atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Haswell, S.J.

    1991-01-01

    Atomic absorption spectroscopy is now well established and widely used technique for the determination of trace and major elements in a wide range analyte types. There have been many advances in the atomic spectroscopy over the last decade and for this reason and to meet the demand, it was felt that there was a need for an updated book. Whilst interest in instrumental design has tended to dominate the minds of the spectrocopist, the analyst concerned with obtaining reliable and representative data, in diverse areas of application, has been diligently modifying and developing sample treatment and instrumental introduction techniques. Such methodology is de fundamental part of analysis and form the basis of the fourteen application chapters of this book. The text focuses in the main on AAS; however, the sample handling techniques described are in many cases equally applicable to ICP-OES and ICP-MS analysis. (author). refs.; figs.; tabs

  6. Elementary relativistic atoms

    International Nuclear Information System (INIS)

    Nemenov, L.

    2001-01-01

    The Coulomb interaction which occurs in the final state between two particles with opposite charges allows for creation of the bound state of these particles. In the case when particles are generated with large momentum in lab frame, the Lorentz factors of the bound state will also be much larger than one. The relativistic velocity of the atoms provides the opportunity to observe bound states of (π + μ - ), (π + π - ) and (π + K - ) with a lifetime as short as 10 -16 s, and to measure their parameters. The ultrarelativistic positronium atoms (A 2e ) allow us to observe the e.ect of superpenetration in matter, to study the effects caused by the formation time of A 2e from virtual e + e - pairs and to investigate the process of transformation of two virtual particles into the bound state

  7. Atomic assistance in 1961

    International Nuclear Information System (INIS)

    1961-01-01

    More than 100 experts provided by the International Atomic Energy Agency will be working in different parts of the world this year, assisting the Agency's Member States in building up their national programs of peaceful atomic development. The total allocation of EPTA funds to the Agency for the two-year period 1961-62 is $1 393 600 (of which approximately half is available in 1961), and is meant not only for the provision of experts and equipment but also for training fellowships and regional projects. The countries which will receive Agency assistance in the form of experts and equipment this year are: Afghanistan, Argentina, Austria, Brazil, Burma, Ceylon, Chile, the Republic of China, Denmark, Greece, Guatemala, Iceland, Indonesia, Iran, Iraq, Israel, Japan, the Republic of Korea, the Republic of Mali, Mexico, Morocco, Pakistan, the Philippines, Senegal, the Sudan, Thailand, Tunisia, Turkey, the United Arab Republic, Vietnam and Yugoslavia

  8. Meteorology and atomic energy

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The science of meteorology is useful in providing information that will be of assistance in the choice of favorable plant locations and in the evaluation of significant relations between meteorology and the design, construction, and operation of plant and facilities, especially those from which radioactive or toxic products could be released to the atmosphere. Under a continuing contract with the Atomic Energy Commission, the Weather Bureau has carried out this study. Some of the meteorological techniques that are available are summarized, and their applications to the possible atmospheric pollution deriving from the use of atomic energy are described. Methods and suggestions for the collection, analysis, and use of meteorological data are presented. Separate abstracts are included of 12 chapters in this publication for inclusion in the Energy Data Base

  9. Laser cooling of a magnetically guided ultra cold atom beam

    Energy Technology Data Exchange (ETDEWEB)

    Aghajani-Talesh, Anoush

    2014-07-01

    This thesis examines two complimentary methods for the laser cooling of a magnetically guided ultra-cold atom beam. If combined, these methods could serve as a starting point for high-through put and possibly even continuous production of Bose-Einstein condensates. First, a mechanism is outlined to harvest ultra cold atoms from a magnetically guided atom beam into an optical dipole trap. A continuous loading scheme is described that dissipates the directed kinetic energy of a captured atom via deceleration by a magnetic potential barrier followed by optical pumping to the energetically lowest Zeeman sublevel. The application of this scheme to the transfer of ultra cold chromium atoms from a magnetically guided atom beam into a deep optical dipole trap is investigated via numerical simulations of the loading process. Based on the results of the theoretical studies the feasibility and the efficiency of our loading scheme, including the realisation of a suitable magnetic field configuration, are analysed. Second, experiments were conducted on the transverse laser cooling of a magnetically guided beam of ultra cold chromium atoms. Radial compression by a tapering of the guide is employed to adiabatically heat the beam. Inside the tapered section heat is extracted from the atom beam by a two-dimensional optical molasses perpendicular to it, resulting in a significant increase of atomic phase space density. A magnetic offset field is applied to prevent optical pumping to untrapped states. Our results demonstrate that by a suitable choice of the magnetic offset field, the cooling beam intensity and detuning, atom losses and longitudinal heating can be avoided. Final temperatures below 65 μK have been achieved, corresponding to an increase of phase space density in the guided beam by more than a factor of 30.

  10. Laser cooling of a magnetically guided ultra cold atom beam

    International Nuclear Information System (INIS)

    Aghajani-Talesh, Anoush

    2014-01-01

    This thesis examines two complimentary methods for the laser cooling of a magnetically guided ultra-cold atom beam. If combined, these methods could serve as a starting point for high-through put and possibly even continuous production of Bose-Einstein condensates. First, a mechanism is outlined to harvest ultra cold atoms from a magnetically guided atom beam into an optical dipole trap. A continuous loading scheme is described that dissipates the directed kinetic energy of a captured atom via deceleration by a magnetic potential barrier followed by optical pumping to the energetically lowest Zeeman sublevel. The application of this scheme to the transfer of ultra cold chromium atoms from a magnetically guided atom beam into a deep optical dipole trap is investigated via numerical simulations of the loading process. Based on the results of the theoretical studies the feasibility and the efficiency of our loading scheme, including the realisation of a suitable magnetic field configuration, are analysed. Second, experiments were conducted on the transverse laser cooling of a magnetically guided beam of ultra cold chromium atoms. Radial compression by a tapering of the guide is employed to adiabatically heat the beam. Inside the tapered section heat is extracted from the atom beam by a two-dimensional optical molasses perpendicular to it, resulting in a significant increase of atomic phase space density. A magnetic offset field is applied to prevent optical pumping to untrapped states. Our results demonstrate that by a suitable choice of the magnetic offset field, the cooling beam intensity and detuning, atom losses and longitudinal heating can be avoided. Final temperatures below 65 μK have been achieved, corresponding to an increase of phase space density in the guided beam by more than a factor of 30.

  11. A Transportable Gravity Gradiometer Based on Atom Interferometry

    Science.gov (United States)

    Yu, Nan; Thompson, Robert J.; Kellogg, James R.; Aveline, David C.; Maleki, Lute; Kohel, James M.

    2010-01-01

    rest frame for the trapped atoms. While still in this moving-frame molasses, the laser frequencies are further detuned from the atomic resonance (while maintaining this relative frequency shift) to cool the atom cloud's temperature to 2 K or below, corresponding to an rms velocity of less than 2 cm/s. After launch, the cold atoms undergo further state and velocity selection to prepare for atom interferometry. The atom interferometers are then realized using laser-induced stimulated Raman transitions to perform the necessary manipulations of each atom, and the resulting interferometer phase is measured using laser-induced fluorescence for state-normalized detection. More than 20 laser beams with independent controls of frequency, phase, and intensity are required for this measurement sequence. This instrument can facilitate the study of Earth's gravitational field from surface and air vehicles, as well as from space by allowing gravity mapping from a low-cost, single spacecraft mission. In addition, the operation of atom interferometer-based instruments in space offers greater sensitivity than is possible in terrestrial instruments due to the much longer interrogation times available in the microgravity environment. A space-based quantum gravity gradiometer has the potential to achieve sensitivities similar to the GRACE mission at long spatial wavelengths, and will also have resolution similar to GOCE for measurement at shorter length scales.

  12. Glossary of atomic terms

    International Nuclear Information System (INIS)

    1982-04-01

    This glossary, containing almost 400 terms, has been compiled to help people outside the atomic energy industry to understand what those inside it are saying. It is not intended to be a definitive dictionary of scientific or technical terms, nor does it aim to cover terms that are in general use in science and technology. A list of about 100 initials and acronyms will be found at the end. (author)

  13. Glossary of atomic terms

    International Nuclear Information System (INIS)

    1980-01-01

    This glossary (of about 400 terms) has been compiled to help people outside the atomic energy industry to understand what those inside it are saying. It is not intended to be a definitive dictionary of scientific or technical terms, nor does it aim to cover terms that are in general use in science and technology. A list of some initials and acronyms is appended. (author)

  14. Fragmentation of atomic systems

    International Nuclear Information System (INIS)

    Bohn, J.L.; Fano, U.

    1996-01-01

    We report recent progress toward a nonperturbative formulation of many-body quantum dynamics that treats all constituent particles on an equal footing. This formulation is capable of detailing the evolution of a system toward the diverse fragments into which it can break up. We illustrate the general concept with the simple example of the simultaneous excitation of both electrons in a helium atom. copyright 1996 The American Physical Society

  15. Atomic and molecular theory

    International Nuclear Information System (INIS)

    Inokuti, Mitio.

    1990-01-01

    The multifaceted role of theoretical physics in understanding the earliest stages of radiation action is discussed. Scientific topics chosen for the present discourse include photoabsorption, electron collisions, and ionic collisions, and electron transport theory, Connections of atomic and molecular physics with condensed-matter physics are also discussed. The present article includes some historical perspective and an outlook for the future. 114 refs., 3 figs

  16. Navigation with Atom Interferometers

    Science.gov (United States)

    2017-03-20

    of frequency L . This problem can be found in many standard quantum optics textbooks e.g [6]. In textbooks , the two states are usually ground and...imprinted” on the atom. Taking into account all three laser pulses, the phase difference then becomes )2()(2)0( TtTtt   , (4a

  17. Atomic emission spectroscopy

    Science.gov (United States)

    Andrew, K. H.

    1975-01-01

    The relationship between the Slater-Condon theory and the conditions within the atom as revealed by experimental data was investigated. The first spectrum of Si, Rb, Cl, Br, I, Ne, Ar, and Xe-136 and the second spectrum of As, Cu, and P were determined. Methods for assessing the phase stability of fringe counting interferometers and the design of an autoranging scanning system for digitizing the output of an infrared spectrometer and recording it on magnetic tape are described.

  18. Atomic and molecular theory

    Energy Technology Data Exchange (ETDEWEB)

    Inokuti, Mitio.

    1990-01-01

    The multifaceted role of theoretical physics in understanding the earliest stages of radiation action is discussed. Scientific topics chosen for the present discourse include photoabsorption, electron collisions, and ionic collisions, and electron transport theory, Connections of atomic and molecular physics with condensed-matter physics are also discussed. The present article includes some historical perspective and an outlook for the future. 114 refs., 3 figs.

  19. A comprehensive analysis of molecule-intrinsic quasi-atomic, bonding, and correlating orbitals. I. Hartree-Fock wave functions

    International Nuclear Information System (INIS)

    West, Aaron C.; Schmidt, Michael W.; Gordon, Mark S.; Ruedenberg, Klaus

    2013-01-01

    Through a basis-set-independent web of localizing orbital-transformations, the electronic wave function of a molecule is expressed in terms of a set of orbitals that reveal the atomic structure and the bonding pattern of a molecule. The analysis is based on resolving the valence orbital space in terms of an internal space, which has minimal basis set dimensions, and an external space. In the internal space, oriented quasi-atomic orbitals and split-localized molecular orbitals are determined by new, fast localization methods. The density matrix between the oriented quasi-atomic orbitals as well as the locations of the split-localized orbitals exhibit atomic populations and inter-atomic bonding patterns. A correlation-adapted quasi-atomic basis is determined in the external orbital space. The general formulations are specified in detail for Hartree-Fock wave functions. Applications to specific molecules exemplify the general scheme

  20. Australia's atomic conspiracy theory

    International Nuclear Information System (INIS)

    Binnie, A.

    2001-01-01

    The author questions claims by the Newcastle University historian Wayne Reynolds in his book 'Australia's Bid for the Bomb', that the impetus behind the Snowy Mountains Scheme was to provide a secure source of power for the enrichment of uranium and production of heavy water so that Australia could produce its own atomic bombs. Reynolds also argued that the Australian Atomic Energy Commission (AAEC) was set up so that Australia had a trained scientific workforce to produce plutonium for the bomb. While the book is well researched, Reynolds does not seem to understand the principles of basic science and engineering. After the Second World War, a manufacturing and industrial base with a skilled and trained workforce was needed so it could be converted to war or defence manufacturing when the need arose. This new manufacturing community would require electrical power to sustain it. Hydroelectricity and atomic energy could help provide these needs. Even though war was still raging, Prime Minister John Curtin looked ahead and set up a Department of Post-War Reconstruction. It was through this department that the Snowy Mountains Scheme would be established. Curtin did not live to see this. He died in 1945 but his successor, Ben Chifley, continued the vision. The author believes, an understanding of the science behind these developments and an appreciation of how how humans interact with each others when it comes to getting something they want is likely to give a more balanced view of the past

  1. Ghost imaging with atoms

    Science.gov (United States)

    Khakimov, R. I.; Henson, B. M.; Shin, D. K.; Hodgman, S. S.; Dall, R. G.; Baldwin, K. G. H.; Truscott, A. G.

    2016-12-01

    Ghost imaging is a counter-intuitive phenomenon—first realized in quantum optics—that enables the image of a two-dimensional object (mask) to be reconstructed using the spatio-temporal properties of a beam of particles with which it never interacts. Typically, two beams of correlated photons are used: one passes through the mask to a single-pixel (bucket) detector while the spatial profile of the other is measured by a high-resolution (multi-pixel) detector. The second beam never interacts with the mask. Neither detector can reconstruct the mask independently, but temporal cross-correlation between the two beams can be used to recover a ‘ghost’ image. Here we report the realization of ghost imaging using massive particles instead of photons. In our experiment, the two beams are formed by correlated pairs of ultracold, metastable helium atoms, which originate from s-wave scattering of two colliding Bose-Einstein condensates. We use higher-order Kapitza-Dirac scattering to generate a large number of correlated atom pairs, enabling the creation of a clear ghost image with submillimetre resolution. Future extensions of our technique could lead to the realization of ghost interference, and enable tests of Einstein-Podolsky-Rosen entanglement and Bell’s inequalities with atoms.

  2. Relativistic correlations in atoms

    International Nuclear Information System (INIS)

    Dietz, K.

    1987-01-01

    Atoms are particularly well-suited objects when it comes to testing certain concepts of many-body theories. They play a unique role in this respect because of two constructively interfering reasons: first of all, the laws describing the interactions of their constituents are the ones best known in all of Physics; secondly, their structure is comparatively simple and amenable to concise theoretical treatment. Because of these two reasons, physically motivated many-body approximation schemes, ordered in a systematic hierarchy of precision, can be carefully tested; discrepancies between theory and experiment are due to many-body effects and are never masked by uncertainties in the constituent-interaction (needless to say, the very small hadronic contributions to atomic structure is left out. Many-body effects in atoms are solely produced by the electron-electron interaction which derives from the laws of Quantum Electrodynamics or, in a very good approximation from the repulsive Coulomb potential; in the general nomenclature they are named correlations. The material is organized in two chapters: chapter 1 deals with a general introduction and discussion of g-Hartree mean-field theories, chapter 2 deals with applications. The role of vacuum fluctuations and deformations of the Dirac sea in a consistent construction of mean-fields is emphasized and their explicit form in the g-Hartree theory is given. 21 references, 5 figures, 3 tables

  3. A new atomic model

    International Nuclear Information System (INIS)

    Petrescu, Florian Ion

    2012-01-01

    The movement of an electron around the atomic nucleus has today a great importance in many engineering fields. Electronics, aeronautics, micro and nanotechnology, electrical engineering, optics, lasers, nuclear power, computing, equipment and automation, telecommunications, genetic engineering, bioengineering, special processing, modern welding, robotics, energy and electromagnetic wave field is today only a few of the many applications of electronic engineering. This book presents, shortly, a new and original relation (20 and 20') who determines the radius with that, the electron is running around the nucleus of an atom. One utilizes, two times the Lorenz relation, the Niels Bohr generalized equation, and a mass relation, which was deduced from the kinematics energy relation written in two modes: classical and Coulombian. Equalizing the mass relation with Lorenz relation one obtains a form which is a relation between the squared electron speed (v 2 ) and the radius (r). The second relation between v 2 and r was obtained by equalizing the mass of Bohr equation and the mass of Lorenz relation. For a Bohr energetically level (n=a constant value), one determines now two energetically below levels, which form an electronic layer. The author realizes by this a new atomic model, or a new quantum theory, which explains the existence of electron-clouds without spin.Writing the kinematics energy relation in two modes, classical and Coulombian one determines a relation, from which explicitely the mass of the electron is determined.

  4. A new atomic model

    Energy Technology Data Exchange (ETDEWEB)

    Petrescu, Florian Ion

    2012-07-01

    The movement of an electron around the atomic nucleus has today a great importance in many engineering fields. Electronics, aeronautics, micro and nanotechnology, electrical engineering, optics, lasers, nuclear power, computing, equipment and automation, telecommunications, genetic engineering, bioengineering, special processing, modern welding, robotics, energy and electromagnetic wave field is today only a few of the many applications of electronic engineering. This book presents, shortly, a new and original relation (20 and 20') who determines the radius with that, the electron is running around the nucleus of an atom. One utilizes, two times the Lorenz relation, the Niels Bohr generalized equation, and a mass relation, which was deduced from the kinematics energy relation written in two modes: classical and Coulombian. Equalizing the mass relation with Lorenz relation one obtains a form which is a relation between the squared electron speed (v{sup 2}) and the radius (r). The second relation between v{sup 2} and r was obtained by equalizing the mass of Bohr equation and the mass of Lorenz relation. For a Bohr energetically level (n=a constant value), one determines now two energetically below levels, which form an electronic layer. The author realizes by this a new atomic model, or a new quantum theory, which explains the existence of electron-clouds without spin.Writing the kinematics energy relation in two modes, classical and Coulombian one determines a relation, from which explicitely the mass of the electron is determined.

  5. Atomic-level computer simulation

    International Nuclear Information System (INIS)

    Adams, J.B.; Rockett, Angus; Kieffer, John; Xu Wei; Nomura, Miki; Kilian, K.A.; Richards, D.F.; Ramprasad, R.

    1994-01-01

    This paper provides a broad overview of the methods of atomic-level computer simulation. It discusses methods of modelling atomic bonding, and computer simulation methods such as energy minimization, molecular dynamics, Monte Carlo, and lattice Monte Carlo. ((orig.))

  6. Atomic inner-shell physics

    International Nuclear Information System (INIS)

    Crasemann, B.

    1985-01-01

    This book discusses: relativistic and quantum electrodynamic effects on atomic inner shells; relativistic calculation of atomic transition probabilities; many-body effects in energetic atomic transitions; Auger Electron spectrometry of core levels of atoms; experimental evaluation of inner-vacancy level energies for comparison with theory; mechanisms for energy shifts of atomic K-X rays; atomic physics research with synchrotron radiation; investigations of inner-shell states by the electron energy-loss technique at high resolution; coherence effects in electron emission by atoms; inelastic X-ray scattering including resonance phenomena; Rayleigh scattering: elastic photon scattering by bound electrons; electron-atom bremsstrahlung; X-ray and bremsstrahlung production in nuclear reactions; positron production in heavy-ion collisions, and X-ray processes in heavy-ion collisions

  7. Into the atom and beyond

    CERN Document Server

    1989-01-01

    Magnifying an atom to football pitch size. The dense nucleus, carrying almost all the atomic mass, is much smaller than the ball. The players (the electrons) would see something about the size of a marble!

  8. Atomic physics issues in fusion

    International Nuclear Information System (INIS)

    Post, D.E.

    1982-01-01

    Atomic physics issues have played a large role in controlled fusion research. A general introduction to the present role of atomic processes in both inertial and magnetic controlled fusion work is presented. (Auth.)

  9. Real and Hybrid Atomic Orbitals.

    Science.gov (United States)

    Cook, D. B.; Fowler, P. W.

    1981-01-01

    Demonstrates that the Schrodinger equation for the hydrogenlike atom separates in both spheroconal and prolate spheroidal coordinates and that these separations provide a sound theoretical basis for the real and hybrid atomic orbitals. (Author/SK)

  10. Physics of atoms and molecules

    International Nuclear Information System (INIS)

    Bransden, B.H.; Joachain, C.J.

    1983-01-01

    This book presents a unified account of the physics of atoms and molecules at a level suitable for second- and third-year undergraduate students of physics and physical chemistry. Following a brief historical introduction to the subject the authors outline the ideas and approximation methods of quantum mechanics to be used later in the book. Six chapters look at the structure of atoms and the interactions between atoms and electromagnetic radiation. The authors then move on to describe the structure of molecules and molecular spectra. Three chapters deal with atomic collisions, the scattering of electrons by atoms and the scattering of atoms by atoms. The concluding chapter considers a few of the many important applications of atomic physics within astrophysics, laser technology, and nuclear fusion. Problems are given at the end of each chapter, with hints at the solutions in an appendix. Other appendices include various special topics and derivations together with useful tables of units. (author)

  11. Capture of muons in atoms

    International Nuclear Information System (INIS)

    Vogel, P.

    1978-01-01

    A lecture is given on the general theoretical framework developed for the description of the formation of mesic atom and the initial part of the atomic cascade. Some of the observable phenomena are also discussed. 16 references

  12. Quantum Optics in Phase Space

    Science.gov (United States)

    Schleich, Wolfgang P.

    2001-04-01

    Quantum Optics in Phase Space provides a concise introduction to the rapidly moving field of quantum optics from the point of view of phase space. Modern in style and didactically skillful, Quantum Optics in Phase Space prepares students for their own research by presenting detailed derivations, many illustrations and a large set of workable problems at the end of each chapter. Often, the theoretical treatments are accompanied by the corresponding experiments. An exhaustive list of references provides a guide to the literature. Quantum Optics in Phase Space also serves advanced researchers as a comprehensive reference book. Starting with an extensive review of the experiments that define quantum optics and a brief summary of the foundations of quantum mechanics the author Wolfgang P. Schleich illustrates the properties of quantum states with the help of the Wigner phase space distribution function. His description of waves ala WKB connects semi-classical phase space with the Berry phase. These semi-classical techniques provide deeper insight into the timely topics of wave packet dynamics, fractional revivals and the Talbot effect. Whereas the first half of the book deals with mechanical oscillators such as ions in a trap or atoms in a standing wave the second half addresses problems where the quantization of the radiation field is of importance. Such topics extensively discussed include optical interferometry, the atom-field interaction, quantum state preparation and measurement, entanglement, decoherence, the one-atom maser and atom optics in quantized light fields. Quantum Optics in Phase Space presents the subject of quantum optics as transparently as possible. Giving wide-ranging references, it enables students to study and solve problems with modern scientific literature. The result is a remarkably concise yet comprehensive and accessible text- and reference book - an inspiring source of information and insight for students, teachers and researchers alike.

  13. New sources of cold atoms for atomic clocks

    International Nuclear Information System (INIS)

    Aucouturier, E.

    1997-01-01

    The purpose of this doctoral work is the realisation of new sources of cold cesium atoms that could be useful for the conception of a compact and high-performance atomic clock. It is based on experiences of atomic physics using light induced atomic manipulation. We present here the experiences of radiative cooling of atoms that have been realised at the Laboratoire de l'Horloge Atomique from 1993 to 1996. Firstly, we applied the techniques of radiative cooling and trapping of atoms in order to create a three-dimensional magneto-optical trap. For this first experience, we developed high quality laser sources, that were used for other experiments. We imagined a new configuration of trapping (two-dimensional magneto-optical trap) that was the basis for a cold atom source. This design gives the atoms a possibility to escape towards one particular direction. Then, we have extracted the atoms from this anisotropic trap in order to create a continuous beam of cold atoms. We have applied three methods of extraction. Firstly, the launching of atoms was performed by reducing the intensity of one of the cooling laser beams in the desired launching direction. Secondly, a frequency detuning between the two laser laser beams produced the launching of atoms by a so-called 'moving molasses'. The third method consisted in applying a static magnetic field that induced the launching of atoms in the direction of this magnetic field. At the same time, another research on cold atoms was initiated at the I.H.A. It consisted in cooling a large volume of atoms from a cell, using an isotropic light. This offers an interesting alternative to the traditional optical molasses. (author)

  14. Elementary Atom Interaction with Matter

    OpenAIRE

    Mrowczynski, Stanislaw

    1998-01-01

    The calculations of the elementary atom (the Coulomb bound state of elementary particles) interaction with the atom of matter, which are performed in the Born approximation, are reviewed. We first discuss the nonrelativistic approach and then its relativistic generalization. The cross section of the elementary atom excitation and ionization as well as the total cross section are considered. A specific selection rule, which applies for the atom formed as positronium by particle-antiparticle pa...

  15. Sacred Space.

    Science.gov (United States)

    Adelstein, Pamela

    2018-01-01

    A space can be sacred, providing those who inhabit a particular space with sense of transcendence-being connected to something greater than oneself. The sacredness may be inherent in the space, as for a religious institution or a serene place outdoors. Alternatively, a space may be made sacred by the people within it and events that occur there. As medical providers, we have the opportunity to create sacred space in our examination rooms and with our patient interactions. This sacred space can be healing to our patients and can bring us providers opportunities for increased connection, joy, and gratitude in our daily work.

  16. Sobolev spaces

    CERN Document Server

    Adams, Robert A

    2003-01-01

    Sobolev Spaces presents an introduction to the theory of Sobolev Spaces and other related spaces of function, also to the imbedding characteristics of these spaces. This theory is widely used in pure and Applied Mathematics and in the Physical Sciences.This second edition of Adam''s ''classic'' reference text contains many additions and much modernizing and refining of material. The basic premise of the book remains unchanged: Sobolev Spaces is intended to provide a solid foundation in these spaces for graduate students and researchers alike.* Self-contained and accessible for readers in other disciplines.* Written at elementary level making it accessible to graduate students.

  17. Rapid prototyping of versatile atom chips for atom interferometry applications.

    Science.gov (United States)

    Kasch, Brian; Squires, Matthew; Olson, Spencer; Kroese, Bethany; Imhof, Eric; Kohn, Rudolph; Stuhl, Benjamin; Schramm, Stacy; Stickney, James

    2016-05-01

    We present recent advances in the manipulation of ultracold atoms with ex-vacuo atom chips (i.e. atom chips that are not inside to the UHV chamber). Details will be presented of an experimental system that allows direct bonded copper (DBC) atom chips to be removed and replaced in minutes, requiring minimal re-optimization of parameters. This system has been used to create Bose-Einstein condensates, as well as magnetic waveguides with precisely tunable axial parameters, allowing double wells, pure harmonic confinement, and modified harmonic traps. We investigate the effects of higher order magnetic field contributions to the waveguide, and the implications for confined atom interferometry.

  18. Finding the Atomic Configuration with a Required Physical Property in Multi-Atom Structures

    International Nuclear Information System (INIS)

    d'Avezac, M.; Zunger, A.

    2007-01-01

    In many problems in molecular and solid state structures one seeks to determine the energy-minimizing decoration of sites with different atom types. In other problems, one is interested in finding a decoration with a target physical property (e.g. alloy band gap) within a certain range. In both cases, the sheer size of the configurational space can be horrendous. We present two approaches which identify either the minimum-energy configuration or configurations with a target property for a fixed underlying Bravais lattice. We compare their efficiency at locating the deepest minimum energy configuration of face centered cubic Au-Pd alloy. We show that a global-search genetic-algorithm approach with diversity-enhancing constraints and reciprocal-space mating can efficiently find the global optimum, whereas the local-search virtual-atom approach presented here is more efficient at finding structures with a target property

  19. Breaking the atom with Samson

    NARCIS (Netherlands)

    Väänänen, J.; Coecke, B.; Ong, L.; Panangaden, P.

    2013-01-01

    The dependence atom =(x,y) was introduced in [11]. Here x and y are finite sets of attributes (or variables) and the intuitive meaning of =(x,y) is that the attributes x completely (functionally) determine the attributes y. One may wonder, whether the dependence atom is truly an atom or whether it

  20. Polarizational radiation or 'atomic' bremsstrahlung

    International Nuclear Information System (INIS)

    Ya Amusia, M.

    1992-01-01

    It is demonstrated that a new kind of continuum spectrum radiation exists, where the mechanism of formation is quite different from that of ordinary bremsstrahlung. The latter originates due to slowing down of the charged projectile in the target field, while the former, called polarization radiation or 'atomic' bremsstrahlung, is a result of radiation either of the target or the projectile particles dipolarly polarized during the collision process. Not only general formulae, but also results of concrete calculations are presented. These demonstrate, that for electron-atom collisions the atomic contribution to the total bremsstrahlung spectrum becomes dominant for photon energies near and above the atomic ionization potential. As to atom-atom or ion-atom collisions, the bremsstrahlung spectrum is completely determined by the atomic contribution. The specific features of the case when the incoming particles are relativistic are discussed at length. A number of examples of colliding pairs are considered, for which the atomic bremsstrahlung process is quite essential: A bare nucleus and an atom, pair of atoms, at least one of which is excited, electron, or atom interacting with a molecule. The same mechanism is essential also in formation of radiation in nuclear and elementary particle collisions. (orig.)