WorldWideScience

Sample records for absorber-materials atomic numbers

  1. Contribution of recoil atoms to irradiation damage in absorber materials

    Science.gov (United States)

    Simeone, D.; Hablot, O.; Micalet, V.; Bellon, P.; Serruys, Y.

    1997-08-01

    Absorbing materials are used to control the reactivity of nuclear reactors by taking advantage of nuclear reactions (e.g., 10B(n,α) 7Li) where neutrons are absorbed. During such reactions, energetic recoils are produced. As a result, radiation damage in absorbing materials originates both from these nuclear reactions and from elastic collisions between neutrons and atoms. This damage eventually leads to a partial destruction of the materials, and this is the main limitation on their lifetime in nuclear reactors. Using a formalism developed to calculate displacements per atoms (dpa) in a multi atomic target, we have calculated damages in terms of displacements per atom in a (n,α) absorbing material taking into account geometrical effects of 10 boron self shielding and transmutation reactions induced by neutrons inside the absorber. Radiation damage is calculated for boron carbide and hafnium diboride ceramics in a Pressurized Water Reactor environment. It is shown that recoils produced by nuclear reactions account for the main part of the radiation damage created in these ceramics. Damages are calculated as a function of the distance from the center of an absorber pellet. Due to the self-shielding effect, these damage curves exhibit sharp maxima, the position of which changes in time.

  2. Advanced neutron absorber materials

    Science.gov (United States)

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  3. High Atom Number in Microsized Atom Traps

    Science.gov (United States)

    2015-12-14

    Final Performance Report on ONR Grant N00014-12-1-0608 High atom number in microsized atom traps for the period 15 May 2012 through 14 September...TYPE Final Technical Report 3. DATES COVERED (From - To) 05/15/2012-09/14/2012 4. TITLE AND SUBTITLE High atom number in microsized atom traps...forces for implementing a small-footprint, large-number atom -chip instrument. Bichromatic forces rely on absorption and stimulated emission to produce

  4. Porcelain enamel neutron absorbing material

    Science.gov (United States)

    Iverson, Daniel C.

    1990-01-01

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  5. Hydrogen heat treatment of hydrogen absorbing materials

    Science.gov (United States)

    Park, Choong-Nyeon

    2000-12-01

    This study introduces the hydrogen heat treatment of hydrogen absorbing materials and its applicability for practical use. This treatment is somewhat different from normal heat treatment because of the interaction between metal atoms and hydrogen. Since hydrogen can be removed very fast by pumping it out the hydrogen-induced new lattice phase which can not be obtained without hydrogen can be preserved in a meta-stable state. A thermodynamic interpretation of the hydrogen heat treatment established previously was reformulated for graphical and analytical methods and applied to Pd-Pt-H and Pd-Ag-H alloy systems and a fair correlation between the calculation and experimental results was shown. The feasibility of applying the thermodynamic interpretation to intermetallic compounds-hydrogen systems was also discussed.

  6. Multiobjective Topology Optimization of Energy Absorbing Materials

    Science.gov (United States)

    2015-08-01

    125–143 DOI 10.1007/s00158-014-1117-8 RESEARCH PAPER Multiobjective topology optimization of energy absorbing materials Raymond A. Wildman · George A...recent developments. J Multiscale Model 3(4):1–42 Qiao P, Yang M, Bobaru F (2008) Impact mechanics and high-energy absorbing materials: review . J Aerosp...ARL-RP-0533 ● AUG 2015 US Army Research Laboratory Multiobjective Topology Optimization of Energy Absorbing Materials by

  7. Space Compatible Radar Absorbing Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate novel radar absorbing materials (RAM) for use in space or simulated space environments. These materials are lightweight...

  8. Durability of Polymeric Glazing and Absorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Terwilliger, K.; Bingham, C.; Lindquist, C.; Milbourne, M.

    2005-11-01

    The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. We have begun evaluation of several new UV-screened polycarbonate sheet glazing constructions. This has involved interactions with several major polymer industry companies to obtain improved candidate samples. Proposed absorber materials were tested for UV resistance, and appear adequate for unglazed ICS absorbers.

  9. Absorber Materials at Room and Cryogenic Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    F. Marhauser, T.S. Elliott, A.T. Wu, E.P. Chojnacki, E. Savrun

    2011-09-01

    We recently reported on investigations of RF absorber materials at cryogenic temperatures conducted at Jefferson Laboratory (JLab). The work was initiated to find a replacement material for the 2 Kelvin low power waveguide Higher Order Mode (HOM) absorbers employed within the original cavity cryomodules of the Continuous Electron Beam Accelerator Facility (CEBAF). This effort eventually led to suitable candidates as reported in this paper. Furthermore, though constrained by small funds for labor and resources, we have analyzed a variety of lossy ceramic materials, several of which could be usable as HOM absorbers for both normal conducting and superconducting RF structures, e.g. as loads in cavity waveguides and beam tubes either at room or cryogenic temperatures and, depending on cooling measures, low to high operational power levels.

  10. Porphyrin Based Near Infrared-Absorbing Materials for Organic Photovoltaics

    Science.gov (United States)

    Zhong, Qiwen

    photosynthesis. Photosynthesis uses light from the sun to drive a series of chemical reactions. Most natural photosynthetic systems utilize chlorophylls to absorb light energy and carry out photochemical charge separation that stores energy in the form of chemical bonds. The sun produces a broad spectrum of light output that ranges from gamma rays to radio waves. The entire visible range of light (400-700 nm) and some wavelengths in the NIR (700-1000 nm), are highly active in driving photosynthesis. Although the most familiar chlorophyll-containing organisms, such as plants, algae and cyanobacteria, cannot use light longer than 700 nm, anoxygenic bacterium containing bacteriochlorophylls can use the NIR part of the solar spectrum. No organism is known to utilize light of wavelength longer than about 1000 nm for photosynthesis. NIR light has a very low-energy content in each photon, so that large numbers of these low-energy photons would have to be used to drive the chemical reactions of photosynthesis. This is thermodynamically possible but would require a fundamentally different molecular mechanism that is more akin to a heat engine than to photochemistry. Early work on developing light absorbing materials for OPVs was inspired by photosynthesis in which light is absorbed by chlorophyll. Structurally related to chlorophyll is the porphyrin family, which has accordingly drawn much interest as the potential light absorbing component in OPV applications. In this dissertation, the design and detail studies of several porphyrin-based NIR absorbing materials, including pi--extended perylenyl porphryins and pyrazole-containing carbaporphyrins, as well as porphyrin modified single-walled carbon nanotube hybrids, will be presented, dedicating efforts to develop novel and application-oriented materials for efficient utilization of sustainable solar energy.

  11. Preparation of A New Type of Stress-absorbed Material

    Institute of Scientific and Technical Information of China (English)

    WU Shao-peng; YANG Tao; YUAN Hai-qing

    2004-01-01

    Neoprene latex modified emulsified bitumen and fine aggregate are used to prepare a new type of stress-absorbed material, which has strong ability of anti-reflective cracking on asphalt concrete over layer-constructed upon a semi-rigid type base course or cement concrete pavement block. Experimental results demonstrate the stress-absorbed material have excellent mechanical properties including a low modulus of elasticity, high ultimate tensile stress and strain, and a strong distortion ability. Stress concentration in asphalt over layer originated by temperature changes and traffic loads can be alleviated.

  12. Investigation of systematic errors of metastable "atomic pair" number

    CERN Document Server

    Yazkov, V

    2015-01-01

    Sources of systematic errors in analysis of data, collected in 2012, are analysed. Esti- mations of systematic errors in a number of “atomic pairs” fr om metastable π + π − atoms are presented.

  13. EM wave propagation analysis in plasma covered radar absorbing material

    CERN Document Server

    Singh, Hema; Rawat, Harish Singh

    2017-01-01

    This book focuses on EM propagation characteristics within multilayered plasma-dielectric-metallic media. The method used for analysis is impedance transformation method. Plasma covered radar absorbing material is approximated as a multi-layered dielectric medium. The plasma is considered to be bounded homogeneous/inhomogeneous medium. The reflection coefficient and hence return loss is analytically derived. The role of plasma parameters, such as electron density, collision frequency, plasma thickness, and plasma density profile in the absorption behavior of multi-layered plasma-RAM structure is described. This book provides a clearer picture of EM propagation within plasma. The reader will get an insight of plasma parameters that play significant role in deciding the absorption characteristics of plasma covered surfaces.

  14. [Shaping of electron radiation fields using homogeneous absorbent materials].

    Science.gov (United States)

    Eichhorn, M; Reis, A; Kraft, M

    1990-01-01

    Proof of shielding and forming by absorbers was done in water phantom dosimetrically. Alterations of isodose course were measured in dependence of primary energy, as well as of thickness and density of the absorber materials. Piacryl or aluminium are not suitable for forming of irregular electron fields. They only effect a reduction of therapeutic range. For primary energies of 10.0 less than or equal to MeV less than or equal to E0- less than or equal to 20.0 MeV lead rubber and wood metal are to recommended in a thickness of less than or equal to 10 mm or less than or equal to 8 mm respectively.

  15. Simulated mixed absorbers and effective atomic numbers for attenuation

    Indian Academy of Sciences (India)

    K Karunakaran Nair; N Ramachandran; K K Abdullah; K M Varier

    2006-09-01

    The total -ray interaction crosss-sections on mixed absorbers were determined at 662 keV with a view to study the effective atomic numbers for -ray absorption under narrow beam good geometry set-up. The measurements were taken for the combination of metallic absorbers like aluminium, copper, lead and mercury and also for the simulated absorbers by rotating the targets. ORTEC HPGe and NaI(Tl) detectors were used for detection of -rays.The experimental results compare favourably with theoretical values derived from XCOM package and suggest the usefulness of the concept of effective atomic numbers and the utility of the rotating absorbers technique.

  16. Low atomic number coating for XEUS silicon pore optics

    DEFF Research Database (Denmark)

    Lumb, D.H.; Cooper-Jensen, Carsten P.; Krumrey, M.

    2008-01-01

    of XEUS graze angles are presented. Reflectance is significantly enhanced for low energies when a low atomic number over-coating is applied. Modeling of the layer thicknesses and roughness is used to investigate the dependence on the layer thicknesses, metal and over coat material choices. We compare...

  17. Development of a new solid-state absorber material for dye-sensitized solar cell (DSSC)

    Indian Academy of Sciences (India)

    Swapna Lilly Cyriac; B Deepika; Bhaskaran Pillai; S V Nair; K R V Subramanian

    2014-05-01

    In contrast to the conventional DSSC systems, where the dye molecules are used as light harvesting material, here a solid-state absorber was used as a sensitizer in conjunction with the dye. The materials like ZnO and Al2O3 : C, which will show optically stimulated luminescence (OSL) upon irradiation were used as extremely thin absorber layers. This novel architecture allows broader spectral absorption, an increase in photocurrent, and hence, an improved efficiency because of the mobility of the trapped electrons in the absorber material after irradiation, to the TiO2 conduction band. Nanocrystalline mesoporous TiO2 photoanodes were fabricated using these solid-state absorber materials and after irradiation, a few number of samples were co-sensitized with N719 dye. On comparing both the dye loaded photoanodes (ZnO/TiO2 and Al2O3 : C/TiO2), it can be concluded from the present studies that, the Al2O3 : C is superior to ZnO under photon irradiation. Al2O3 : C is more sensitive to photon irradiation than ZnO and hence there can be more trap centres produced in Al2O3 : C.

  18. The Effect of Reflector with Sound-Absorbing Material on Supersonic Jet Noise

    Institute of Scientific and Technical Information of China (English)

    Y.-H. KWEON; M. TSUCHIDA; Y. MIYAZATO; T. AOKI; H.-D. KIM; T. SETOGUCHI

    2005-01-01

    This paper describes an experimental work to investigate the effect of a reflector on supersonic jet noise radiated from a convergent-divergent nozzle with a design Mach number 2.0. In the present study, a metal reflector and reflectors made of three different sound-absorbing materials (grass wool and polyurethane foam) were employed,and the reflector size was varied. Acoustic measurement is carried out to obtain the acoustic characteristics such as frequency, amplitude of screech tone and overall sound pressure level (OASPL). A high-quality schlieren optical system is used to visualize the detailed structure of supersonic jet. The results obtained show that the acoustic characteristics of supersonic jet noise are strongly dependent upon the jet pressure ratio and the reflector size. It is also found that the reflector with sound-absorbing material reduces the screech tone amplitude by about 5-13dB and the overall sound pressure levels by about 2-5dB, compared with those of the metal reflector.

  19. Recent Advances in Conjugated Polymer-Based Microwave Absorbing Materials

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2017-01-01

    Full Text Available Microwave absorbing materials (MAMs are paving the way for exciting applications in electromagnetic (EM pollution precaution and national defense security, as they offer an advanced alternative to conventional reflection principles to fundamentally eliminate the EM waves. Conjugated polymer (CP-based composites appear as a promising kind of MAM with the desirable features of low density and high performance. In this review, we introduce the theory of microwave absorption and summarize recent advances in the fabrication of CP-based MAMs, including rational design of the microstructure of pure conjugated polymers and tunable chemical integration with magnetic ferrites, magnetic metals, transition metal oxides, and carbon materials. The key point of enhancing microwave absorption in CP-based MAMs is to regulate their EM properties, improve matching of characteristic impedance, and create diversified loss mechanisms. The examples presented in this review will provide new insights into the design and preparation of CP-based composites that can satisfy the high demands of the oncoming generation of MAMs.

  20. Simulation of shock absorbing materials loaded by drop weights

    Energy Technology Data Exchange (ETDEWEB)

    Kasparek, Eva; Voelzke, Holger; Scheidemann, Robert [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2013-08-15

    The numerical simulation of transport and storage casks for radioactive waste in accidental scenarios requires adequate material models and input parameters for all relevant structural cask elements, the impact foundation as well as possibly further components involved in the incident. They form the basis for reliable analysis of different loading situations allowing substituting, at least in parts, experimental investigations that are needed in safety reports submitted for nuclear licensing procedures. Hereby, the efficiency of the energy absorbing components, such as cask impact limiters or equivalent structures placed onto or into the foundation of storage buildings, determine to a large extend the performance and thus the design of the casks. The limiters, which are usually made of wood, polyurethane foam (PUF) or damping concrete, are subjected to major plastic deformations, whose distribution and magnitude strongly depend on loading speed, course and temperature. Consequently, it is necessary to establish a systematic data basis and implement this information in advanced numerical material formulations in order to enable finite element simulations to account for all relevant factors. Since the end of 2008, BAM (Bundesanstalt fuer Materialforschung und -pruefung) is supported by the Federal Ministry of Education and Research in order to determine such experimental data as well as to adapt and develop qualified material models for shock absorbing materials in the framework of a project called ENREA. (orig.)

  1. Synthesis of a new element with atomic number Z=117

    Energy Technology Data Exchange (ETDEWEB)

    Oganessian, Yuri Ts. [FLNR-JINR, Russia; Abdullin, F. Sh. [Joint Institute for Nuclear Research, Dubna, Russia; Bailey, P. D. [Oak Ridge National Laboratory (ORNL); Benker, D. E. [Oak Ridge National Laboratory (ORNL); Bennett, M. E. [University of Nevada, Las Vegas; Dmitriev, S. [FLNR-JINR, Russia; Ezold, Julie G. [Oak Ridge National Laboratory (ORNL); Hamilton, J. H. [Vanderbilt University; Henderson, R. [Lawrence Livermore National Laboratory (LLNL); Itkis, M. G. [FLNR-JINR, Russia; Lobanov, Yu. V. [Joint Institute for Nuclear Research, Dubna, Russia; Mezentsev, A. N. [Joint Institute for Nuclear Research, Dubna, Russia; Moody, K. [Lawrence Livermore National Laboratory (LLNL); Nelson, S. L. [Lawrence Livermore National Laboratory (LLNL); Polyakov, A. N. [Joint Institute for Nuclear Research, Dubna, Russia; Porter, C. E. [Oak Ridge National Laboratory (ORNL); Ramayya, A. V. [Vanderbilt University; Riley, F. D. [Oak Ridge National Laboratory (ORNL); Roberto, James B [ORNL; Ryabinin, M. A. [Research Institute of Atomic Reactors, Dimitrovgrad, Russia; Rykaczewski, Krzysztof Piotr [ORNL; Sagaidak, R. N. [Joint Institute for Nuclear Research, Dubna, Russia; Shaughnessy, D. [Lawrence Livermore National Laboratory (LLNL); Shirokovsky, I. V. [Joint Institute for Nuclear Research, Dubna, Russia; Stoyer, M. [Lawrence Livermore National Laboratory (LLNL); Subbotin, V. G. [Joint Institute for Nuclear Research, Dubna, Russia; Sudowe, R. [University of Nevada, Las Vegas; Sukhov, A. M. [Joint Institute for Nuclear Research, Dubna, Russia; Tsyganov, Yu. S. [Joint Institute for Nuclear Research, Dubna, Russia; Utyonkov, V. [FLNR-JINR, Russia; Voinov, A. A. [Joint Institute for Nuclear Research, Dubna, Russia; Vostokin, G. K. [Joint Institute for Nuclear Research, Dubna, Russia; Wilk, P. A. [Lawrence Livermore National Laboratory (LLNL)

    2010-01-01

    The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes 293117 and 294117 were produced in fusion reactions between 48Ca and 249Bk. Decay chains involving eleven new nuclei were identified by means of the Dubna Gas Filled Recoil Separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z111, validating the concept of the long sought island of enhanced stability for super-heavy nuclei.

  2. Synthesis of a new element with atomic number Z = 117.

    Science.gov (United States)

    Oganessian, Yu Ts; Abdullin, F Sh; Bailey, P D; Benker, D E; Bennett, M E; Dmitriev, S N; Ezold, J G; Hamilton, J H; Henderson, R A; Itkis, M G; Lobanov, Yu V; Mezentsev, A N; Moody, K J; Nelson, S L; Polyakov, A N; Porter, C E; Ramayya, A V; Riley, F D; Roberto, J B; Ryabinin, M A; Rykaczewski, K P; Sagaidak, R N; Shaughnessy, D A; Shirokovsky, I V; Stoyer, M A; Subbotin, V G; Sudowe, R; Sukhov, A M; Tsyganov, Yu S; Utyonkov, V K; Voinov, A A; Vostokin, G K; Wilk, P A

    2010-04-09

    The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes (293)117 and (294)117 were produced in fusion reactions between (48)Ca and (249)Bk. Decay chains involving 11 new nuclei were identified by means of the Dubna gas-filled recoil separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z > or = 111, validating the concept of the long sought island of enhanced stability for superheavy nuclei.

  3. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  4. A model for acoustic absorbent materials derived from coconut fiber

    Directory of Open Access Journals (Sweden)

    Ramis, J.

    2014-03-01

    Full Text Available In the present paper, a methodology is proposed for obtaining empirical equations describing the sound absorption characteristics of an absorbing material obtained from natural fibers, specifically from coconut. The method, which was previously applied to other materials, requires performing measurements of air-flow resistivity and of acoustic impedance for samples of the material under study. The equations that govern the acoustic behavior of the material are then derived by means of a least-squares fit of the acoustic impedance and of the propagation constant. These results can be useful since they allow the empirically obtained analytical equations to be easily incorporated in prediction and simulation models of acoustic systems for noise control that incorporate the studied materials.En este trabajo se describe el proceso seguido para obtener ecuaciones empíricas del comportamiento acústico de un material absorbente obtenido a partir de fibras naturales, concretamente el coco. El procedimiento, que ha sido ensayado con éxito en otros materiales, implica la realización de medidas de impedancia y resistencia al flujo de muestras del material bajo estudio. Las ecuaciones que gobiernan el comportamiento desde el punto de vista acústico del material se obtienen a partir del ajuste de ecuaciones de comportamiento de la impedancia acústica y la constante de propagación del material. Los resultados son útiles ya que, al disponer de ecuaciones analíticas obtenidas empíricamente, facilitan la incorporación de estos materiales en predicciones mediante métodos numéricos del comportamiento cuando son instalados formando parte de dispositivos para el control del ruido.

  5. Kriging atomic properties with a variable number of inputs

    Science.gov (United States)

    Davie, Stuart J.; Di Pasquale, Nicodemo; Popelier, Paul L. A.

    2016-09-01

    A new force field called FFLUX uses the machine learning technique kriging to capture the link between the properties (energies and multipole moments) of topological atoms (i.e., output) and the coordinates of the surrounding atoms (i.e., input). Here we present a novel, general method of applying kriging to chemical systems that do not possess a fixed number of (geometrical) inputs. Unlike traditional kriging methods, which require an input system to be of fixed dimensionality, the method presented here can be readily applied to molecular simulation, where an interaction cutoff radius is commonly used and the number of atoms or molecules within the cutoff radius is not constant. The method described here is general and can be applied to any machine learning technique that normally operates under a fixed number of inputs. In particular, the method described here is also useful for interpolating methods other than kriging, which may suffer from difficulties stemming from identical sets of inputs corresponding to different outputs or input biasing. As a demonstration, the new method is used to predict 54 energetic and electrostatic properties of the central water molecule of a set of 5000, 4 Å radius water clusters, with a variable number of water molecules. The results are validated against equivalent models from a set of clusters composed of a fixed number of water molecules (set to ten, i.e., decamers) and against models created by using a naïve method of treating the variable number of inputs problem presented. Results show that the 4 Å water cluster models, utilising the method presented here, return similar or better kriging models than the decamer clusters for all properties considered and perform much better than the truncated models.

  6. New absorbent material acoustic based on kenaf’s fibre

    Directory of Open Access Journals (Sweden)

    Ramis, J.

    2010-09-01

    Full Text Available Acoustic Standards in the building are responsible for, companies and individuals, propose new acoustic materials for the sound isolation. This paper presents a new sound-absorbent material, it is based on natural fibres, particularly fibres of kenaf. It also proposes an empirical model for this material, this models depends on the frequency. There are accepted models from the scientific community about mineral wool, glass wool, rock wool, foam or polyester fibre. Several of these models are empirical. They are obtained from the equation adjustments about the acoustic impedance and propagation constant behaviour, depending upon the flow resistivity, fibre’s diameter and density. There are even standards like UNE-EN 12354-6 where these models are accepted under certain limitations like the fundamental basis as in the materials’ acoustics behaviour prediction. From the various tests conducted in the laboratory, empirical equations are proposed for this new acoustic material. In addition, there has been a first approach to validate this model in combination with a micro-structural model, based on the steps taken by Bies-Hansen (1, which allows us to obtain the value of the resistance to flow.

    El carácter marcadamente prestacional de las normativas acústicas en la edificación abre el camino a la propuesta, por parte de empresas y particulares, de nuevos materiales acústicos susceptibles de ser utilizados en el ámbito de la acústica de la edificación. Éste es el caso que nos ocupa en el presente trabajo en el que se presenta un nuevo material acústico absorbente basado en fibras vegetales, concretamente el kenaf. Además se propone un modelo empírico de modelización del comportamiento absorbente de varias composiciones de este material en función de la frecuencia. Existen modelos de diferentes lanas minerales, lanas de roca, lanas de vidrio, espumas o lanas de poliéster. Algunos de estos modelos —llamados empíricos— se

  7. Effective atomic numbers of some composite mixtures including borax

    Energy Technology Data Exchange (ETDEWEB)

    Bastug, Arif [Department of Physics, Faculty of Art and Science, Aksaray University, Aksaray (Turkey); Guerol, Ali [Department of Physics, Faculty of Sciences, Atatuerk University, Erzurum (Turkey); Icelli, Orhan, E-mail: oicelli@yildiz.edu.t [Department of Physics, Faculty of Art and Sciences, Yildiz Technical University, Davutpasa 34220, Istanbul (Turkey); Sahin, Yusuf [Department of Physics, Faculty of Sciences, Atatuerk University, Erzurum (Turkey)

    2010-07-15

    Effective atomic numbers for (PbO and Na{sub 2}B{sub 4}O{sub 7}10H{sub 2}O) and (UO{sub 2}(NO{sub 3}){sub 2}, and Na{sub 2}B{sub 4}O{sub 7}10H{sub 2}O) mixtures against changing contents of PbO, Na{sub 2}B{sub 4}O{sub 7}10H{sub 2}O, and UO{sub 2}(NO{sub 3}){sub 2} were measured in the X-ray energy range from 25.0 to 58.0 keV. The gamma rays emitted by a {sup 241}Am annular source have been sent on the absorbers which emits their characteristic X-rays to be used in transmission arrangement. The X-rays were counted by a Si(Li) detector with a resolution of 146 eV at 5.90 keV. The changing compositions of the compounds were assigned to be 0, 0.167, 0.333, 0.500, 0.666, 0.833 and total masses of the mixtures were adjusted to be identical. Also, the total effective atomic numbers of each mixture were estimated by using the mixture rule. The measured values were compared with estimated values for the mixtures.

  8. Morphological and photophysical characterisation of novel absorber materials for organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Hannah; Lieberwirth, Ingo; Meister, Michael; Howard, Ian H.; Laquai, Frederic [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany); Janietz, Silvia [Fraunhofer Institut fuer Angewandte Polymerforschung, Potsdam (Germany)

    2011-07-01

    In this contribution new tailor-made fluorene based terpolymers are investigated as absorber materials in organic solar cells. These terpolymers contain different contents of dialkyl-substituted diphenyl-benzopyrazine or diphenyl-thienopyrazine and triphenylamine units and possess bandgaps between 1.3 and 1.8 eV. Power conversion efficiencies up to 3% with open circuit voltages close to 1 V are obtained in blends with [6,6]-phenyl C{sub 61} butyric acid methyl ester (PCBM) even without prior thermal treatment. The morphology of the blends is investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM) and correlated with the results obtained from I-V-measurements under simulated sunlight. Photophysical experiments such as steady-state photoinduced absorption (PIA) and transient absorption (TA) spectroscopy are employed to understand the effect of variation of the polymer structure on exciton dissociation and charge recombination. Using a combination of these methods the understanding of the structure-property-relationship of these materials is extended towards the molecular scale and the impact of molecular structure and processing conditions on charge generation, transport and recombination processes can be elucidated.

  9. Quick-Determination of the Average Atomic Number Z by X-Ray Scattering

    DEFF Research Database (Denmark)

    Kunzendorf, Helmar

    1972-01-01

    X-ray scattering ratio measurements are proposed for a quick determination of the average atomic number of rock powders.......X-ray scattering ratio measurements are proposed for a quick determination of the average atomic number of rock powders....

  10. Disk emission and absorption lines in LMXB. Note on the physical conditions of an absorbing material

    CERN Document Server

    Rozanska, Agata

    2014-01-01

    We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption lines can be satisfactorily modeled by the spectrum from an accretion disk atmosphere. We performed full radiative transfer calculations using our code ATM21 to model the emission from an accretion disk surface that is seen at different viewing angles. Computed models are then fitted to the high-resolution X-ray spectra of 4U 1630-472 obtained by {\\it Suzaku} satellite. Absorption lines of highly ionized iron originating in a hot accretion-disk atmospheres are important part of the observed line profile, and can be an alternative or complementary explanation to the wind model usually favored for this type of sources. Next, assuming that absorption lines originate from the wind illuminated by X-ray central source in LMXBs, we can put constrains on the wind location only if we know the volume density number of the absorbing material. There are a few derivations of the distance to the wind in X-ray binaries. We show here, that the dens...

  11. Levelized Cost of Coating (LCOC) for selective absorber materials

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Clifford K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pacheco, James E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-08

    A new metric has been developed to evaluate and compare selective absorber coatings for concentrating solar power applications. Previous metrics have typically considered the performance of the selective coating (i.e., solar absorptance and thermal emittance), but cost and durability were not considered. This report describes the development of the levelized cost of coating (LCOC), which is similar to the levelized cost of energy (LCOE) commonly used to evaluate alternative energy technologies. The LCOC is defined as the ratio of the annualized cost of the coating (and associated costs such as labor and number of heliostats required) to the average annual thermal energy produced by the receiver. The baseline LCOC using Pyromark 2500 paint was found to be %240.055/MWht, and the distribution of LCOC values relative to this baseline were determined in a probabilistic analysis to range from -%241.6/MWht to %247.3/MWht, accounting for the cost of additional (or fewer) heliostats required to yield the same baseline average annual thermal energy produced by the receiver. A stepwise multiple rank regression analysis showed that the initial solar absorptance was the most significant parameter impacting the LCOC, followed by thermal emittance, degradation rate, reapplication interval, and downtime during reapplication.

  12. Study on Absorbing Materials%吸波材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    李娅

    2012-01-01

    With the rapid development of stealth technique, absorbing materials becomes the key materials of stealth technique for modem weapon. This paper mainly introduced the concept of absorbing materials, absorbing mechanism and classification, the application prospect of absorbing materials is also elaborated.%随着隐身技术的快速发展,波吸收材料成为现代武器隐身技术的关键材料之一.本文主要介绍了吸波材料的概念,吸波原理和分类,并阐述了吸波材料的发展趋势及应用前景.

  13. Moseley's Work on X-Rays and Atomic Number.

    Science.gov (United States)

    Haigh, C. W.

    1995-01-01

    Highlights the connection between the achievements of Moseley and the spectrum of the hydrogen atom, the Bohr theory, and Slater's rules for screening constants. Uses modern data to show that Moseley's equation is actually an approximation and discusses the significance of this fact. (JRH)

  14. Absorbent Material

    Science.gov (United States)

    1985-01-01

    A superabsorbent fabric developed by Johnson Space Center and described in Tech Briefs was adapted by Honeywell and fabricated into special containment devices used on Navy "smart" torpedos. The superabsorbent fabric can sequester up to 400 times its own weight in water and protects the torpedo electronic controls from possible short circuiting by deepwater hull seepage.

  15. Determination of the effective atomic number of thick samples of unknown composition using scattering studies

    Science.gov (United States)

    Sankarshan, B. M.; Athrey, C. D.; Umesh, T. K.

    2017-06-01

    The effective atomic number ( Z_eff is a quantity which gives the fraction of the total number of electrons in a composite material participating in the photon-atom interaction. The effective atomic number has been determined for the materials of known composition by using different methods. However, no method has been reported so far to determine Z_eff for thick samples of unknown composition. In view of this, we have evolved a simple method to determine the effective atomic number, which uses the scattering intensity ratios measured at two scattering angles, in which a sample of known Z_eff or Z is taken as a reference sample. The values of Z_eff obtained by this method agree with those obtained from the Auto-Zeff software within the stated errors. This method could be helpful in determining the effective atomic number of samples of unknown composition.

  16. Analysis and evaluation of RF absorbing material in suppressing modes associated with a metallic cavity

    Science.gov (United States)

    Green, David L.

    Application of absorbing materials within enclosures designed to house high-speed digital electronics has become common practice for suppressing resonances associated with the enclosure geometry. Use of absorbing material is often considered toward the end of the design phase when the product is undergoing electromagnetic compatibility compliance testing, leaving little time for the additional experimentation required to optimize absorber material selection or placement within the device. The engineering principles required for maximizing absorber performance within the enclosure are often disregarded, replaced by a "shotgun" approach where multiple material options are experimented with until a solution is achieved. For this research a frequency domain reverberation chamber technique and one-port time domain quality factor estimation technique are employed to quantify the ability of various absorbing materials to suppress resonances of a physically small, electrically large cavity representative of those that may be used to enclose high-speed circuitry. Using both measurement techniques, assessment of the performance of various absorbing materials was performed as well as an evaluation of the affect absorber position has on overall material performance. It was found that both measurement techniques were effective in quantifying absorber performance within the cavity. For the frequency domain reverberation chamber approach the absorber effectiveness, defined as the difference in insertion loss between the cavity with and without absorbing material, was analyzed for various materials. For the undermoded cavity it was found that absorber effectiveness was positionally dependent. For the overmoded cavity, however, the position of the absorber within the cavity, as long as the total exposed surface area remained constant, did not have a significant impact on the absorber effectiveness. Similar results were also found by comparing the estimated quality factor for

  17. Effective atomic numbers of some tissue substitutes by different methods: A comparative study

    Directory of Open Access Journals (Sweden)

    Vishwanath P Singh

    2014-01-01

    Full Text Available Effective atomic numbers of some human organ tissue substitutes such as polyethylene terephthalate, red articulation wax, paraffin 1, paraffin 2, bolus, pitch, polyphenylene sulfide, polysulfone, polyvinylchloride, and modeling clay have been calculated by four different methods like Auto-Z eff, direct, interpolation, and power law. It was found that the effective atomic numbers computed by Auto-Z eff , direct and interpolation methods were in good agreement for intermediate energy region (0.1 MeV < E < 5 MeV where the Compton interaction dominates. A large difference in effective atomic numbers by direct method and Auto-Z eff was observed in photo-electric and pair-production regions. Effective atomic numbers computed by power law were found to be close to direct method in photo-electric absorption region. The Auto-Z eff , direct and interpolation methods were found to be in good agreement for computation of effective atomic numbers in intermediate energy region (100 keV < E < 10 MeV. The direct method was found to be appropriate method for computation of effective atomic numbers in photo-electric region (10 keV < E < 100 keV. The tissue equivalence of the tissue substitutes is possible to represent by any method for computation of effective atomic number mentioned in the present study. An accurate estimation of Rayleigh scattering is required to eliminate effect of molecular, chemical, or crystalline environment of the atom for estimation of gamma interaction parameters.

  18. Paramagnetic atom number and paramagnetic critical pressure of the sc, bcc and fcc Ising nanolattices

    Science.gov (United States)

    Şarlı, Numan

    2015-01-01

    The effects of the magnetic atom number in the unit volume on the magnetic properties are investigated by using sc (n=8), bcc (n=9) and fcc (n=14) Ising NLs within the effective field theory with correlations. We find that the magnetic properties expand as the magnetic atom number increases in the unit volume and this expanding constitutes an elliptical path at TC. The effect of the magnetic atom number (n) in the unit volume on the magnetic properties (mp) appear as nscconstant is directly proportional with the atom number in the unit volume (C α n). Hence, by using the slopes of the paramagnetic hysteresis curves of any nanosystem, it can be predicted that the number of particles in its unit volume. Moreover, the magnetic atoms in the paramagnetic region can be considered as particles in the gas. Because of the absence of an external magnetic field, the spin orientations of these atoms are random and free to rotate. Hence, they act on individually with no mutual interaction between two nearest-neighbor magnetic atoms. Therefore, we use the statistical mechanics form of the ideal gas law in the paramagnetic region and we obtain the critical paramagnetic pressure (PC=npkBTC) of the Ising NLs at TC. We define the paramagnetic magnetic atom number in the unit volume as np=n(1-M(T)).

  19. Influence of microstructure on properties of Ni–Zn ferrite radio-absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.G., E-mail: ilem58@mail.ru [Kuznetsk Institute of Information and Management Technologies, 57a Mayakovsky Street, Kuznetsk, Penza Region 442540 (Russian Federation); Menshova, S.B.; Klimov, A.N.; Vergazov, R.M. [Kuznetsk Institute of Information and Management Technologies, 57a Mayakovsky Street, Kuznetsk, Penza Region 442540 (Russian Federation); Bibikov, S.B. [N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences (IBCP), 4, Kosygin Street, Moscow 119334 (Russian Federation); Prokofiev, M.V. [Moscow Aviation Institute (National research University), Volokolamkoye shosse, 4, 125871 Moscow (Russian Federation)

    2015-11-15

    In this work there have been carried out studies in the radiophysical characteristics of the samples of Ni–Zn ferrite radio-absorbing materials, obtained by the ceramic method under different technological conditions. There has been established the influence of microstructure on the electromagnetic losses of Ni–Zn ferrite radio-absorbing materials. The results indicate that the coarse-grained structure leads to an increase of radio-absorbing capacity at frequencies below 30 MHz. It can be explained by the resonance of domain boundaries. - Highlights: • Addition of Bi{sub 2}O{sub 3} up to 1 mass% leads to increasing grain sizes of Ni-Zn ferrites. • Coarse-grained structure is achieved adding ferrite particles of a large fraction. • Coarse-grained structure leads to increasing absorbing capacity at low frequencies. • It can be explained by the resonance of domain boundaries.

  20. Research and application of kapok fiber as an absorbing material: a mini review.

    Science.gov (United States)

    Zheng, Yian; Wang, Jintao; Zhu, Yongfeng; Wang, Aiqin

    2015-01-01

    Kapok fiber corresponds to the seed hairs of the kapok tree (Ceiba pentandra), and is a typical cellulosic fiber with the features of thin cell wall, large lumen, low density and hydrophobic-oleophilic properties. As a type of renewable natural plant fiber, kapok fiber is abundant, biocompatible and biodegradable, and its full exploration and potential application have received increasing attention in both academic and industrial fields. Based on the structure and properties of kapok fiber, this review provides a summary of recent research on kapok fiber including chemical and physical treatments, kapok fiber-based composite materials, and the application of kapok fiber as an absorbent material for oils, metal ions, dyes, and sound, with special attention to its use as an oil-absorbing material, one predominant application of kapok fiber in the coming future.

  1. Neutronic analysis of absorbing materials for the control rod system in reactor ALLEGRO

    Energy Technology Data Exchange (ETDEWEB)

    Cajko, Frantisek; Secansky, Michal; Chrebet, Tomas; Zajac, Radoslav; Darilek, Petr [VUJE, a.s., Trnava (Slovakia)

    2016-09-15

    Experimental reactor ALLEGRO is a gas cooled fast reactor in the design stage. The current design of its reactivity control system is based on control rods filled with boron carbide as the absorber. Because of disadvantages connected to high boron enrichment a possibility of using other absorbent materials was explored to lower the boron enrichment and increase the worth of the control rods. The results of neutronic Monte-Carlo analyses in a computational supercell are presented in this paper. Three absorbent materials most suitable for a use in reactor ALLEGRO (B{sub 4}C, EuB{sub 6} and ReB{sub 2}) have been analysed also in a full core model. A possible benefit of a neutron trap concept is explored as well but materials with satisfactory neutronic properties proved to be not suitable for expected high temperatures in the reactor.

  2. Research and application of kapok fiber as an absorbing material: A mini review

    Institute of Scientific and Technical Information of China (English)

    Yian Zheng; Jintao Wang; Yongfeng Zhu; Aiqin Wang

    2015-01-01

    Kapok fiber corresponds to the seed hairs of the kapok tree (Ceiba pentandra),and is a typical cellulosic fiber with the features of thin cell wall,large lumen,low density and hydrophobicoleophilic properties.As a type of renewable natural plant fiber,kapok fiber is abundant,biocompatible and biodegradable,and its full exploration and potential application have received increasing attention in both academic and industrial fields.Based on the structure and properties of kapok fiber,this review provides a summary of recent research on kapok fiber including chemical and physical treatments,kapok fiber-based composite materials,and the application of kapok fiber as an absorbent material for oils,metal ions,dyes,and sound,with special attention to its use as an oil-absorbing material,one predominant application of kapok fiber in the coming future.

  3. On-site monitoring of atomic density number for an all-optical atomic magnetometer based on atomic spin exchange relaxation.

    Science.gov (United States)

    Zhang, Hong; Zou, Sheng; Chen, Xiyuan; Ding, Ming; Shan, Guangcun; Hu, Zhaohui; Quan, Wei

    2016-07-25

    We present a method for monitoring the atomic density number on site based on atomic spin exchange relaxation. When the spin polarization P ≪ 1, the atomic density numbers could be estimated by measuring magnetic resonance linewidth in an applied DC magnetic field by using an all-optical atomic magnetometer. The density measurement results showed that the experimental results the theoretical predictions had a good consistency in the investigated temperature range from 413 K to 463 K, while, the experimental results were approximately 1.5 ∼ 2 times less than the theoretical predictions estimated from the saturated vapor pressure curve. These deviations were mainly induced by the radiative heat transfer efficiency, which inevitably leaded to a lower temperature in cell than the setting temperature.

  4. Determination of molecular, atomic, electronic cross-sections and effective atomic number of some boron compounds and TSW

    Energy Technology Data Exchange (ETDEWEB)

    Icelli, Orhan [Department of physics Education, Faculty of Education Erzincan University, 24030 Erzincan (Turkey)], E-mail: orhanicelli@gmail.com; Erzeneoglu, Salih [Department of physics, Faculty of Sciences, Atatuerk University, Erzurum (Turkey); Boncukcuoglu, Recep [Department of Environmental Engineering, Faculty of Engineering, Atatuerk University, Erzurum (Turkey)

    2008-07-15

    The transmission of gamma-rays of some boron compounds (H{sub 3}BO{sub 3}, Na{sub 2}B{sub 4}O{sub 7}) and the trommel sieve waste (TSW) have been measured by using an extremely narrow-collimated-beam transmission method in the energy range 15.74-40.93 keV. Molecular, atomic and electronic cross-sections and effective atomic numbers have been determinated on the basis of mixture rule and compared with the results obtained from theory.

  5. Effective atomic numbers of some tissue substitutes by different methods: A comparative study.

    Science.gov (United States)

    Singh, Vishwanath P; Badiger, N M

    2014-01-01

    Effective atomic numbers of some human organ tissue substitutes such as polyethylene terephthalate, red articulation wax, paraffin 1, paraffin 2, bolus, pitch, polyphenylene sulfide, polysulfone, polyvinylchloride, and modeling clay have been calculated by four different methods like Auto-Zeff, direct, interpolation, and power law. It was found that the effective atomic numbers computed by Auto-Zeff, direct and interpolation methods were in good agreement for intermediate energy region (0.1 MeV numbers by direct method and Auto-Zeff was observed in photo-electric and pair-production regions. Effective atomic numbers computed by power law were found to be close to direct method in photo-electric absorption region. The Auto-Zeff, direct and interpolation methods were found to be in good agreement for computation of effective atomic numbers in intermediate energy region (100 keV numbers in photo-electric region (10 keV number mentioned in the present study. An accurate estimation of Rayleigh scattering is required to eliminate effect of molecular, chemical, or crystalline environment of the atom for estimation of gamma interaction parameters.

  6. A New CMC-AA Resin/Inorganic-gel Super Absorbent Material

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A super absorbent material was prepared with the super absorbent resin ( SAR ) and inorganicgel.The SAR of the carboxymethyl cellulose grafting acrylic acid ( CMC-AA ) was copolymer synthesized using the method of inverse-phase suspension polymerization. The influences of the monomer concentration, neutralization degree, the initiator, dispersion agent, cross-linking agent, reaction and drying temperature on the grafting copolymer properties were examined.Meanwhlie, its properties was investigated and the model for absorption mechanism of this absorbent composite was proposed.

  7. Experimental Evaluation Of A Single-basin Solar Still Using Different Absorbing Materials: An Overview

    Directory of Open Access Journals (Sweden)

    T.R.TELTUMBADE,

    2011-04-01

    Full Text Available Single-basin solar stills can be used for water desalination. Probably, the are considered the best solution for water production in remote,arid to semi-arid, small communities, where fresh water isunavailable.however,the amount of distilled water produced per unit area is somewhat low which makes the single-basin solar still unacceptable in some instances. The purpose of this paper is to study the effect of using different absorbing materials in a solar still, and thuds enhance the productivity of water. Experimental result show that the productivity of distilled water was enhance for some matereals.

  8. Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th

    CERN Document Server

    Marinov, A; Kolb, D; Pape, A; Kashiv, Y; Brandt, R; Gentry, R V; Miller, H W

    2008-01-01

    Evidence for the existence of a superheavy nucleus with atomic mass number A=292 and abundance (1-10)x10^(-12) relative to 232Th has been found in a study of natural Th using inductively coupled plasma-sector field mass spectrometry. The measured mass matches the predictions [1,2] for the mass of an isotope with atomic number Z=122 or a nearby element. Its estimated half-life of t1/2 >= 10^8 y suggests that a long-lived isomeric state exists in this isotope. The possibility that it might belong to a new class of long-lived high spin super- and hyperdeformed isomeric states is discussed.[3-6

  9. 吸音材料的发展现状与趋势%Development Status-quo of Absorbing Materials

    Institute of Scientific and Technical Information of China (English)

    杨波; 刘亚

    2013-01-01

      本文综述了吸音材料的原理及其分类,主要分析了多孔吸音材料的发展与现状,并重点介绍了非织造吸音材料的的吸音优势、影响因素以及研究进展。%The mechanism and classification of sound-absorbing materials were introduced in this paper. Based on presentation of the advantages, influencing factors and development status-quo of sound-absorbing materials, especially nonwoven sound-absorbing material, the authors gave some suggestions on developing high-performance sound-absorbing materials.

  10. 新型吸波材料研究进展%Research Progress on Novel Wave-Absorbing Materials

    Institute of Scientific and Technical Information of China (English)

    孙志岗; 乔小晶; 任庆国; 李旺昌

    2013-01-01

    以铁氧体复合吸波材料为例,概述了吸波材料发展趋势;介绍了两种新型隐身材料(碳纳米管复合吸波材料和左手材料)的发展现状,并对我国吸波材料的发展提出一些建议.%This paper summarizes the current situation of the development of wave-absorbing materials.And the novel wave-absorbing materials are laid a strong emphasis,which requires light,thin,broad-band and strong materials,such as nano-materials and the left-handed materials.Moreover,the developing trend on novel wave-absorbing materials is prospected.Further more,some suggestions have been provided for the development of the novel wave-absorbing materials in the future.

  11. Determination of effective atomic numbers, effective electrons numbers, total atomic cross-sections and buildup factor of some compounds for different radiation sources

    Science.gov (United States)

    Levet, A.; Özdemir, Y.

    2017-01-01

    The photon interaction parameters such as mass attenuation coefficient, effective atomic number, effective electron density, buildup factor have been measured for Fe(NO3)3, V4O2, NaCO3·H2O, C6H5FeO7·H2O and CuCI compounds using 137Ba, 157Gd and 241Am γ-rays sources in stable geometry. The mass attenuation coefficients have been determined experimentally via Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) system and theoretically by using WinXCom computer program. Then, effective atomic numbers, Zeff, and electron densities, Neff, have been calculated by using the mass attenuation coefficients. The obtained values of effective atomic numbers have been compared with the ones calculated according to a different approach proposed by Hine and the calculated ones from theory. Also, photon buildup factors were obtained by changing collimator diameters in the different photon energies. We observed that the buildup factor increased as the collimator diameter increased for all sources used.

  12. Knitted radar absorbing materials (RAM) based on nickel–cobalt magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Teber, Ahmet, E-mail: aht10003@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States); Unver, Ibrahim, E-mail: iunver@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Kavas, Huseyin, E-mail: huseyin.kavas@medeniyet.edu.tr [Department of Physics, Istanbul Medeniyet University, Istanbul 34000 (Turkey); Aktas, Bekir, E-mail: aktas@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Bansal, Rajeev, E-mail: rajeev@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States)

    2016-05-15

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K{sub u}, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under −20 dB return loss over a moderate bandwidth). - Graphical abstract: Here, we added the graphical abstract that provides summary the contents of the article in a concise pictorial form. - Highlights: • Flexible lightweight, thin, reconfigurable radar absorbing materials are proposed. • Polyacrylonitrile (PAN) fabrics are coated with nickel, cobalt magnetic materials. • The coating times affects microwave constitutive parameters and absorption. • Microwave absorption measurements were done via transmission line technique. • Microwave absorption is due to dielectric losses rather than magnetic losses.

  13. Does the composition of urine change when collected from disposable diapers and other absorbent materials?

    Science.gov (United States)

    Ye, Xiaoyun; Zhou, Xiaoliu; Bishop, Amber M; Needham, Larry L; Calafat, Antonia M

    2010-11-01

    The free and conjugated urinary species of non-persistent environmental chemicals or their breakdown products are valid human exposure biomarkers. For convenience, disposable diapers and other absorbent materials are widely used to collect urine specimens from infants and young toddlers. However, the extent to which the different urinary species of the target analytes and other components are recovered after the urine is extracted from these absorbent materials is unknown. In this proof-of-concept study, we investigated the extraction recovery from disposable diapers, cotton pads, and gauzes of the free versus glucuronidated urinary species of three example chemicals: bisphenol A, triclosan, and 4-methylumbelliferone. Although the glucuronides were almost fully recovered, the free species were not. Our results suggest that, in addition to other sampling considerations, the binding affinity and extraction recovery of the target biomarkers to the material used to collect the urine should be considered. Alternative collection approaches that do not require such an extraction (e.g., urine bags routinely used in hospitals) may be worth exploring. Despite its shortcomings, having urinary concentrations for biomonitoring considerably strengthens the exposure assessment, particularly for infants and young toddlers, and the benefits of including biomonitoring data outweigh their potential limitations.

  14. Absorber Materials for Transition-Edge Sensor X-ray Microcalorimeters

    Science.gov (United States)

    Brown, Ari-David; Bandler, Simon; Brekosky, Regis; Chervenak, James; Figueroa-Feliciano, Enectali; Finkbeiner, Fred; Sadleir, Jack; Iyomoto, Naoko; Kelley, Richard; Kilbourne, Caroline; Porter, F. Scott; Smith, Stephen; Saab, Tarek; Sadleir, Jac,

    2007-01-01

    Arrays of superconducting transition-edge sensors (TES) can provide high spatial and energy resolution necessary for x-ray astronomy. High quantum efficiency and uniformity of response can be achieved with a suitable absorber material, in which absorber x-ray stopping power, heat capacity, and thermal conductivity are relevant parameters. Here we compare these parameters for bismuth and gold. We have fabricated electroplated gold, electroplated gold/electroplated bismuth, and evaporated gold/evaporated bismuth 8x8 absorber arrays and find that a correlation exists between the residual resistance ratio (RRR) and thin film microstructure. This finding indicates that we can tailor absorber material conductivity via microstructure alteration, so as to permit absorber thermalization on timescales suitable for high energy resolution x-ray microcalorimetry. We show that by incorporating absorbers possessing large grain size, including electroplated gold and electroplated gold/electroplated bismuth, into our current Mo/Au TES, devices with tunable heat capacity and energy resolution of 2.3 eV (gold) and 2.1 eV (gold/bismuth) FWHM at 6 keV have been fabricated.

  15. SEPARATION OF PLUTONIUM FROM ELEMENTS HAVING AN ATOMIC NUMBER NOT LESS THAN 92

    Science.gov (United States)

    Fitch, F.T.; Russell, D.S.

    1958-09-16

    other elements having atomic numbers nnt less than 92, It has been proposed in the past to so separate plutonium by solvent extraction iato an organic solvent using triglycoldichlcride as the organic solvent. The improvement lies in the discovery that triglycoldichloride performs far more efflciently as an extractant, wher certain second organie compounds are added to it. Mentioned as satisfactory additive compounds are benzaldehyde, saturated aliphatic aldehydes containtng at least twc carbon atoms, and certain polyhydric phenols.

  16. Temperature and number evolution of cold cesium atoms inside a wall-coated glass cell

    Institute of Scientific and Technical Information of China (English)

    黄家强; 张建伟; 王时光; 王力军

    2015-01-01

    We report an experimental study on the temperature and number evolution of cold cesium atoms diffusively cooled inside a wall-coated glass cell by measuring the absorption profile of the 62S1/2 (F=4)→62P3/2(F0=5) transition line with a weak probe laser in the evolution process. We found that the temperature of the cold atoms first gradually decreases from 16 mK to 9 mK, and then rapidly increases. The number of cold atoms first declines slowly from 2.1 × 109 to 3.7 × 108 and then falls drastically. A theoretical model for the number evolution is built and includes the instantaneous temperature of the cold atoms and a fraction p, which represents the part of cold cesium atoms elastically reflected by the coated cell wall. The theory is overall in good agreement with the experimental result, and a nonzero value is obtained for the fraction p, which indicates that the cold cesium atoms are not all heated to the ambient temperature by a single collision with the coated cell wall. These results can provide helpful insight for precision measurements based on diffuse laser cooling.

  17. Effective atomic numbers for W/Cu alloy using transmission experiments

    Energy Technology Data Exchange (ETDEWEB)

    Murty, V.R.K. E-mail: murtyvrk@mopipi.ub.bw; Winkoun, D.P.; Devan, K.R.S

    2000-11-15

    Attenuation studies on pure elements are straightforward and extensive data sets are available in the literature. However, studies on alloys are meagre due to the nonavailability of alloys of known composition in suitable form. Such studies are useful in estimating effective atomic numbers and to verify the validity of the mixture rule. Empirical expressions for these have been reported in the literature but several discrepancies have been noted. In the present study, transmission experiments were conducted in a narrow beam geometry for the photon energy range 60-400 keV, evaluating the effective atomic numbers for W/Cu alloy of two compositions, 65/35 and 60/40.

  18. The effective atomic numbers of some biomolecules calculated by two methods: A comparative study

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2009-01-01

    The effective atomic numbers Z(eff) of some fatty acids and amino acids have been calculated by two numerical methods, a direct method and an interpolation method, in the energy range of 1 keV-20 MeV. The notion of Z(eff) is given a new meaning by using a modern database of photon interaction cross...... constant and equal to the mean atomic number of the material. Wherever possible, the calculated values of Z(eff) are compared with experimental data....

  19. The splitting of atomic orbitals with a common principal quantum number revisited: np vs. ns.

    Science.gov (United States)

    Katriel, Jacob

    2012-04-14

    Atomic orbitals with a common principal quantum number are degenerate, as in the hydrogen atom, in the absence of interelectronic repulsion. Due to the virial theorem, electrons in such orbitals experience equal nuclear attractions. Comparing states of several-electron atoms that differ by the occupation of orbitals with a common principal quantum number, such as 1s(2) 2s vs. 1s(2) 2p, we find that although the difference in energies, ΔE, is due to the interelectronic repulsion term in the Hamiltonian, the difference between the interelectronic repulsions, ΔC, makes a smaller contribution to ΔE than the corresponding difference between the nuclear attractions, ΔL. Analysis of spectroscopic data for atomic isoelectronic sequences allows an extensive investigation of these issues. In the low nuclear charge range of pertinent isoelectronic sequences, i.e., for neutral atoms and mildly positively charged ions, it is found that ΔC actually reverses its sign. About 96% of the nuclear attraction difference between the 6p (2)P and the 6s (2)S states of the Cs atom is cancelled by the corresponding interelectronic repulsion difference. From the monotonic increase of ΔE with Z it follows (via the Hellmann-Feynman theorem) that ΔL > 0. Upon increasing the nuclear charge along an atomic isoelectronic sequence with a single electron outside a closed shell from Z(c), the critical charge below which the outmost electron is not bound, to infinity, the ratio ΔC/ΔL increases monotonically from lim(Z→Z(c)(+))ΔC/ΔL=-1 to lim(Z→∞)ΔC/ΔL=1. These results should allow for a more nuanced discussion than is usually encountered of the crude electronic structure of many-electron atoms and the structure of the periodic table.

  20. Dielectric microwave absorbing material processed by impregnation of carbon fiber fabric with polyaniline

    Directory of Open Access Journals (Sweden)

    Luiza de Castro Folgueras

    2007-03-01

    Full Text Available It is a known fact that the adequate combination of components and experimental conditions may produce materials with specific requirements. This study presents the effect of carbon fiber fabric impregnation with polyaniline conducting polymer aiming at the radar absorbing material processing. The experiments consider the sample preparation with one and two impregnations. The prepared samples were evaluated by reflectivity measurements, in the frequency range of 8-12 GHz and scanning electron microscopy analyses. The correlation of the results shows that the quantity of impregnated material influences the performance of the processed microwave absorber. This study shows that the proposed experimental route provides flexible absorbers with absorption values of the incident radiation close to 87%.

  1. Study of Solid-Liquid Ratio of Fly Ash Geopolymer as Water Absorbent Material

    Directory of Open Access Journals (Sweden)

    Angga Prasetya Fandi

    2017-01-01

    Full Text Available Geopolymer has been synthesized from fly ash to be applicated as water absorbent material. This research conducted to determine the ability of geopolymer to abrsop water by variation of solid – liquid ratio at optimum molarity of NaOH; 3 M. In this research, the synthesis of geopolymer was conducted at the variation of solid-liquid ratio; 60:40, 65:35, 70:30, and 75:25. Result of the treatment were characterized by XRD and SEM to compare the geopolymer structure. Water absorption capacity was measured by immersing the geopolymer specimens in water for 24 hours. Based on the result, solid – liquid ratio with maximum water absorbed was 70:30 with 13,04 wt%.

  2. Knitted radar absorbing materials (RAM) based on nickel-cobalt magnetic materials

    Science.gov (United States)

    Teber, Ahmet; Unver, Ibrahim; Kavas, Huseyin; Aktas, Bekir; Bansal, Rajeev

    2016-05-01

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, Ku, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under -20 dB return loss over a moderate bandwidth).

  3. Eggshell and Bacterial Cellulose Composite Membrane as Absorbent Material in Active Packaging

    Directory of Open Access Journals (Sweden)

    S. Ummartyotin

    2016-01-01

    Full Text Available Bacterial cellulose and eggshell composite was successfully developed. Eggshell was mixed with bacterial cellulose suspension and it was casted as a composite film. CaCO3 derived from eggshell was compared with its commercial availability. It can be noted that good dispersion of eggshell particle was prepared. Eggshell particle was irregular in shape with a variation in size. It existed in bacterial cellulose network. Characterization on composite was focused on thermal and mechanical properties. It showed that flexibility and thermal stability of composite were enhanced. No significant effect of mechanical properties was therefore observed. The thermal stability of composite was stable up to 300°C. The adsorption experiment on water and vegetable oil capacity was performed. The enhancement on adsorption was due to the existence of eggshell in bacterial cellulose composite. It exhibited the potential to be a good candidate for absorbent material in active packaging.

  4. Estimation of the RF Characteristics of Absorbing Materials in Broad RF Frequency Ranges

    CERN Document Server

    Fandos, R

    2008-01-01

    Absorbing materials are very often used in RF applications. Their electromagnetic characteristics (relative permittivity εr, loss tangent tan δ and conductivity σ) are needed in order to obtain a high-quality design of the absorbing pieces in the frequency range of interest. Unfortunately, suppliers often do not provide these quantities. A simple technique to determine them, based on the RF measurement of the disturbance created by the insertion of a piece of absorber in a waveguide, is presented in this note. Results for samples of two different materials, silicon carbide and aluminum nitride are presented. While the former has a negligible conductivity at the working frequencies, the conductivity of the latter has to be taken into account in order to obtain a meaningful estimation of εr and tan δ. The equations of Kramers & Kronig have been applied to the data as a cross check, confirming the results.

  5. Carbon nanotube scaffolds with controlled porosity as electromagnetic absorbing materials in the gigahertz range.

    Science.gov (United States)

    González, M; Crespo, M; Baselga, J; Pozuelo, J

    2016-05-19

    Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials.

  6. Nanostructured composites based on carbon nanotubes and epoxy resin for use as radar absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Valdirene Aparecida [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil); Folgueras, Luiza de Castro; Candido, Geraldo Mauricio; Paula, Adriano Luiz de; Rezende, Mirabel Cerqueira, E-mail: mirabelmcr@iae.cta.br [Instituto de Aeronautica e Espaco (IAE), Sao Jose dos Campos, SP (Brazil). Div. de Materiais; Costa, Michelle Leali [Universidade Estadual Paulista Julio de Mesquita Filho (DMT/UNESP), Guaratingueta, SP (Brazil). Dept. de Materiais e Tecnologia

    2013-07-01

    Nanostructured polymer composites have opened up new perspectives for multifunctional materials. In particular, carbon nanotubes (CNTs) present potential applications in order to improve mechanical and electrical performance in composites with aerospace application. The combination of epoxy resin with multi walled carbon nanotubes results in a new functional material with enhanced electromagnetic properties. The objective of this work was the processing of radar absorbing materials based on formulations containing different quantities of carbon nanotubes in an epoxy resin matrix. To reach this objective the adequate concentration of CNTs in the resin matrix was determined. The processed structures were characterized by scanning electron microscopy, rheology, thermal and reflectivity in the frequency range of 8.2 to 12.4 GHz analyses. The microwave attenuation was up to 99.7%, using only 0.5% (w/w) of CNT, showing that these materials present advantages in performance associated with low additive concentrations (author)

  7. Radar absorbing materials based on titanium thin film obtained by sputtering technique

    Directory of Open Access Journals (Sweden)

    Viviane Lilian Soethe

    2011-09-01

    Full Text Available Titanium thin films with nanometer thicknesses were deposited on polyethylene terephthalate (PET substrate using the triode magnetron sputtering technique. It was observed that the titanium thin film-polymeric substrate set attenuates the energy of the incident electromagnetic wave in the frequency range of 8 to 12 GHz. This result allows to consider this set as a radar absorbing material, which may be employed in automobile, telecommunication, aerospace, medical, and electroelectronic areas. Results of the reflectivity show that the attenuation depends on the thin film thickness, as a determining factor. Thin films with 25 to 100 nm thickness values show attenuation of the electromagnetic wave energy from around 20 to 50%. Analyses by Rutherford backscattering spectrometry provided information about the thickness of the thin films studied. Hall effect analyses contributed to better understand the influence of the thin film thickness on the electron mobility and consequently on absorption properties.

  8. Study of the antifungal potential of novel cellulose/copper composites as absorbent materials for fruit juices.

    Science.gov (United States)

    Llorens, Amparo; Lloret, Elsa; Picouet, Pierre; Fernandez, Avelina

    2012-08-17

    Cellulose/copper composites with antifungal properties have been synthesized by physical/chemical methods. Physical treatments by heat or by a combination of heat and UV radiation provided composites with metallic copper and excellent interfacial adhesion; in contrast, chemical reduction with borohydride generated small although partially aggregated copper oxide nanoparticles. Copper micro/nano-particles and copper ions (Cu(2+)) were released from the cellulose matrix at an adequate rate to achieve a strong antimicrobial activity against Saccharomyces cerevisiae in in vitro experiments. Moreover, the copper oxide composites showed an excellent antifungal activity in pineapple and melon juice, reducing about 4 log cycles the loads of spoilage-related yeasts and moulds. The metallic copper composites reduced in 4 log cycles the load of yeasts and moulds in pineapple juice, although their antifungal activity was weaker in contact with melon juice. Copper loaded absorbent materials could be selectively implemented during the shelf-life of minimally processed fruits to reduce the number of spoilage-related microorganisms in the drip.

  9. Cheminoes: A Didactic Game to Learn Chemical Relationships between Valence, Atomic Number, and Symbol

    Science.gov (United States)

    Moreno, Luis F.; Hincapié, Gina; Alzate, María Victoria

    2014-01-01

    Cheminoes is a didactic game that enables the meaningful learning of some relations between concepts such as chemical element, valence, atomic number, and chemical symbol for the first 36 chemical elements of the periodic system. Among the students who have played the game, their opinions of the activity were positive, considering the game to be a…

  10. Cheminoes: A Didactic Game to Learn Chemical Relationships between Valence, Atomic Number, and Symbol

    Science.gov (United States)

    Moreno, Luis F.; Hincapié, Gina; Alzate, María Victoria

    2014-01-01

    Cheminoes is a didactic game that enables the meaningful learning of some relations between concepts such as chemical element, valence, atomic number, and chemical symbol for the first 36 chemical elements of the periodic system. Among the students who have played the game, their opinions of the activity were positive, considering the game to be a…

  11. Topological Numbers and Edge State of Hierarchical State in Rapidly Rotating Ultracold Atoms

    Institute of Scientific and Technical Information of China (English)

    ZHAO Bo; CHEN Zeng-Bing

    2005-01-01

    The effective theory for the hierarchical fractional quantum Hall (FQH) effect is proposed. We also derive the topological numbers K matrix and t vector and the general edge excitation from the effective theory. One can find that the two issues in rapidly rotating ultracold atoms are similar to those in electron FQH liquid.

  12. Projectile atomic-number effect on ion-induced fragmentation and ionization of fullerenes

    NARCIS (Netherlands)

    Hadjar, O; Hoekstra, R; Morgenstern, R; Schlatholter, T

    2001-01-01

    The delocalized pi electrons of a C-60 cluster can be well described as an electron gas. Electronic friction experienced by a multicharged ion colliding with a fullerene might then be modeled in terms of the electronic stopping power. We investigated such collisions for projectile atomic numbers Z r

  13. 核壳吸波材料的研究进展∗%Progress in core-shell absorbing materials

    Institute of Scientific and Technical Information of China (English)

    俞梁; 王建江; 许宝才; 李志广; 蔡旭东

    2015-01-01

    As a new core-shell composite absorbing material,as compared with a single type of absorbing mate-rial in the structure,properties and applications of absorbing has obvious advantages,the paper summarizes the basic types of core-shell absorbing materials,preparation methods and proposed a new method for self-reactive quenching + surface modification method.Pointed out that the core-shell absorbing material absorbing material is expected to meet the new"thin,light,wide,strong"requirements,and core-shell absorbing materials re-search proposed future prospects.%核壳吸波材料作为一种新型复合吸波材料,与单一类型的吸波材料相比在结构、吸波性能和应用上有着明显优势,本文总结了核壳吸波材料的基本类型、制备方法及提出了一种新的制备方法-自反应淬熄+表面改性法。指出核壳吸波材料有望满足新型吸波材料“薄、轻、宽、强”的要求,并对今后核壳吸波材料的研究提出展望。

  14. An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

    Science.gov (United States)

    Ross, H. Richard

    1993-01-01

    A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

  15. Dimensionality and Finite Number Effect on BCS Transition of Atomic Fermi Gas

    Institute of Scientific and Technical Information of China (English)

    CUI Hai-Tao; WANG Lin-Cheng; YI Xue-Xi

    2005-01-01

    The effect of finite number and dimensionality has been discussed in this paper. The finite number effect has a negative correction to final temperature for 2D or 3D atomic Fermi gases. The changing of final temperature obtained by scanning from BEC region to BCS region are 10% or so with N ≤ 103 and can be negligible when N > 103.However, in 1D atomic Fermi gas, the effect gives a positive correction which greatly changes the final temperature in Fermi gas. This behavior is completely opposed to the 2D and 3D cases and a proper explanation is still to be found.Dimensionality also has a positive correction, in which the more tightly trapping, the higher final temperature one gets with the same particle number. A discussion is also presented.

  16. The influence of basic composition and microstructures on the properties of Ni-Zn ferrite radio-absorbing materials

    Science.gov (United States)

    Andreev, V. G.; Menshova, S. B.; Klimov, A. N.; Vergazov, R. M.

    2015-11-01

    This work deals with the research into the electromagnetic properties of Ni-Zn ferrite radio-absorbing materials obtained by the ceramic method under different technological conditions. There has been ascertained the influence of basic composition and microstructures on the level of absorption of electromagnetic radiation by Ni-Zn ferrite radio-absorbing materials. The results indicate that increasing the surplus Fe2O3 up to 51.0 mol% leads to a shift in frequency interval in the direction of low frequencies. It can be explained by increase of the permeability and permittivity of a ferrite.

  17. Crystallization of Supercooled Liquid Elements Induced by Superclusters Containing Magic Atom Numbers

    Directory of Open Access Journals (Sweden)

    Robert F. Tournier

    2014-08-01

    Full Text Available A few experiments have detected icosahedral superclusters in undercooled liquids. These superclusters survive above the crystal melting temperature Tm because all their surface atoms have the same fusion heat as their core atoms, and are melted by liquid homogeneous and heterogeneous nucleation in their core, depending on superheating time and temperature. They act as heterogeneous growth nuclei of crystallized phase at a temperature Tc of the undercooled melt. They contribute to the critical barrier reduction, which becomes smaller than that of crystals containing the same atom number n. After strong superheating, the undercooling rate is still limited because the nucleation of 13-atom superclusters always reduces this barrier, and increases Tc above a homogeneous nucleation temperature equal to Tm/3 in liquid elements. After weak superheating, the most stable superclusters containing n = 13, 55, 147, 309 and 561 atoms survive or melt and determine Tc during undercooling, depending on n and sample volume. The experimental nucleation temperatures Tc of 32 liquid elements and the supercluster melting temperatures are predicted with sample volumes varying by 18 orders of magnitude. The classical Gibbs free energy change is used, adding an enthalpy saving related to the Laplace pressure change associated with supercluster formation, which is quantified for n = 13 and 55.

  18. Carbon nanotube scaffolds with controlled porosity as electromagnetic absorbing materials in the gigahertz range

    Science.gov (United States)

    González, M.; Crespo, M.; Baselga, J.; Pozuelo, J.

    2016-05-01

    Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials.Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials. Electronic supplementary information (ESI) available: Scheme of hydrogenated derivative of diglycidyl ether of bisphenol-A (HDGEBA) and m-xylylenediamine; X-ray diffractograms of pristine CNT

  19. Dynamical decoherence in a cavity with a large number of two-level atoms

    CERN Document Server

    Frasca, M

    2004-01-01

    We consider a large number of two-level atoms interacting with the mode of a cavity in the rotating-wave approximation (Tavis-Cummings model). We apply the Holstein-Primakoff transformation to study the model in the limit of the number of two-level atoms, all in their ground state, becoming very large. The unitary evolution that we obtain in this approximation is applied to a macroscopic superposition state showing that, when the coherent states forming the superposition are enough distant, then the state collapses on a single coherent state describing a classical radiation mode. This appear as a true dynamical effect that could be observed in experiments with cavities.

  20. Silver atom and strand numbers in fluorescent and dark Ag:DNAs.

    Science.gov (United States)

    Schultz, Danielle; Gwinn, Elisabeth G

    2012-06-11

    We use tandem HPLC-mass spectrometry with in-line spectroscopy to identify silver atom numbers, N(Ag), of 10 to 21 in visible- to infrared-emitting Ag:DNA complexes stabilized by oligonucleotide monomers and dimers. Qualitatively different absorbance spectra from bare, same-N(Ag) silver clusters point to silver-base interactions as the origin for the color of Ag:DNAs.

  1. Potential application of a homogeneous and anisotropic slab as an angle insensitive absorbing material

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2017-06-01

    Full Text Available In this paper, a flat and incident angle independence absorbing material is proposed and numerically verified in the optical spectrum. A homogeneous and anisotropic dielectric slab as a non-reflecting layer is first reviewed, and a feasible realization strategy of the slab is then given by using layered isotropic materials. When the loss components of the constitutive materials are not zero, the slab will work as an angle insensitive absorbing layer, and the absorption rate augments with increase of the losses. As the numerical verifications, the field distributions of a metallic cylinder and a triangular metallic object individually covered by the designed absorbing layer are demonstrated. The simulation results show that the designed absorbing layer can efficiently absorb the incident waves with the property of incident angle independence at the operation frequency. This homogeneous slab can be used in one and two dimensional situations for the realization of an invisibility cloak, a carpet cloak and even a skin cloak, if it is used to conformally cover target objects.

  2. Predicted sound absorption coefficients of absorber materials lined in a chamber

    Directory of Open Access Journals (Sweden)

    Farhad Forouharmajd

    2014-01-01

    Full Text Available Aims: The present study was aimed to measurement of sound absorption coefficient of mineral wool and determination of their absorption ability. Materials and Methods: Mineral wool was used to find noise absorption coefficient. Random and normal sound absorption coefficient values were predicted. Then, the measures of transmission loss calculated as an overall value, for applied absorbent material and bare sheet metal. Results: The measured values of noise with one octave band frequency demonstrated an attenuation of 5.5-7 dB for these frequencies. The absorption coefficients of materials showed that mineral wool had more normal sound coefficients than its random sound absorption coefficient values. Conclusion: It can be concluded that predicted normal sound absorption coefficients of used mineral wool materials were near to the areas of standard line. It seems that the amount or thickness of absorbent lining was a main reason of noise reduction in low band frequencies. Mineral wool has a higher density and can provide better acoustical and insulating results than fiberglass. Besides, mineral wool doesn′t lose its insulating value when wet and has an outstanding resistance to fire.

  3. Development of microwave absorbing materials prepared from a polymer binder including Japanese lacquer and epoxy resin

    Science.gov (United States)

    Iwamaru, T.; Katsumata, H.; Uekusa, S.; Ooyagi, H.; Ishimura, T.; Miyakoshi, T.

    Microwave absorption composites were synthesized from a poly urushiol epoxy resin (PUE) mixed with one of microwave absorbing materials; Ni-Zn ferrite, Soot, Black lead, and carbon nano tube (CNT) to investigate their microwave absorption properties. PUE binders were specially made from Japanese lacquer and epoxy resin, where Japanese lacquer has been traditionally used for bond and paint because it has excellent beauty. Japanese lacquer solidifies with oxygen contained in air's moisture, which has difficulty in making composite, but we improved Japanese lacquer's solidification properties by use of epoxy resin. We made 10 mm thickness composite samples and cut them into toroidal shape to measure permittivity, permeability, and reflection loss in frequencies ranging from 50 Hz to 20 GHz. Electric magnetic absorber's composites synthesized from a PUE binders mixed either with Soot or CNT showed significantly higher wave absorption over -27 dB than the others at frequencies around 18 GHz, although Japanese lacquer itself doesn't affect absorption. This means Japanese lacquer can be used as binder materials for microwave absorbers.

  4. Producing of Impedance Tube for Measurement of Acoustic Absorption Coefficient of Some Sound Absorber Materials

    Directory of Open Access Journals (Sweden)

    R. Golmohammadi

    2008-04-01

    Full Text Available Introduction & Objective: Noise is one of the most important harmful agents in work environment. In spit of industrial improvements, exposure with over permissible limit of noise is counted as one of the health complication of workers. In Iran, do not exact information of the absorption coefficient of acoustic materials. Iranian manufacturer have not laboratory for measured of sound absorbance of their products, therefore using of sound absorber is limited for noise control in industrial and non industrial constructions. The goal of this study was to design an impedance tube based on pressure method for measurement of the sound absorption coefficient of acoustic materials.Materials & Methods: In this study designing of measuring system and method of calculation of sound absorption based on a available equipment and relatively easy for measurement of the sound absorption coefficient related to ISO10534-1 was performed. Measuring system consist of heavy asbestos tube, a pure tone sound generator, calibrated sound level meter for measuring of some commonly of sound absorber materials was used. Results: In this study sound absorption coefficient of 23 types of available acoustic material in Iran was tested. Reliability of results by three repeat of measurement was tested. Results showed that the standard deviation of sound absorption coefficient of study materials was smaller than .Conclusion: The present study performed a necessary technology of designing and producing of impedance tube for determining of acoustical materials absorption coefficient in Iran.

  5. Enhancing the Performance of the Microwave Absorbing Materials by Using Dielectric Resonator Arrays

    Directory of Open Access Journals (Sweden)

    Omar H. Al-Zoubi

    2017-01-01

    Full Text Available We present a technique for enhancing the performance of microwave absorbing materials in terms of weight, thickness, and bandwidth. The introduced technique is based on fabricating the microwave absorbing (MA material in a structure comprised of an array of circular cylinder dielectric resonators (CDR backed by a perfect electric conductor (PEC ground plane. Numerical electromagnetic methods are employed to study the properties of the proposed MA array structures, where 3D full wave simulation using finite-element method is implemented. The obtained results show that the performance of the MA-CDR arrays significantly outperforms that of a flat layer composed of the same material and having equivalent thickness. A flat layer of MA material with thickness of 5 mm backed by perfect electric conductor (PEC shows as low as -50 dB reflection loss (RL peak and ~3 GHz 10-dB bandwidth, whereas an MA-CDR array, composed of the same MA material, of height of 4 mm can achieve as low as ~−50 dB RL peak and ~12 GHz 10-dB RL bandwidth.

  6. Quantitative imaging of electron density and effective atomic number using phase contrast CT

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen Guanghong, E-mail: gchen7@wisc.ed [Department of Medical Physics, University of Wisconsin-Madison, WI 53705 (United States)

    2010-05-07

    Compared to single energy CT, which only provides information for x-ray linear attenuation coefficients, dual-energy CT is able to obtain both the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual-energy CT, a novel quantitative imaging method based on phase contrast CT is presented. Rather than requiring two projection data sets with different x-ray energy spectra, diffraction-grating-based phase contrast CT is capable of reconstructing images of both linear attenuation and refractive index decrement from the same projection data using a single x-ray energy spectra. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Two physical phantoms were constructed and used to validate the presented method. Experimental results demonstrate that (1) electron density can be accurately determined from refractive index decrement through a linear relationship, and (2) the effective atomic number can be explicitly derived from the ratio of the linear attenuation to refractive index decrement using a power function plus a constant. The presented method will provide insight into the technique of material separation and find its use in medical and industrial applications.

  7. Quantitative imaging of electron density and effective atomic number using phase contrast CT

    Science.gov (United States)

    Qi, Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen, Guang-Hong

    2010-05-01

    Compared to single energy CT, which only provides information for x-ray linear attenuation coefficients, dual-energy CT is able to obtain both the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual-energy CT, a novel quantitative imaging method based on phase contrast CT is presented. Rather than requiring two projection data sets with different x-ray energy spectra, diffraction-grating-based phase contrast CT is capable of reconstructing images of both linear attenuation and refractive index decrement from the same projection data using a single x-ray energy spectra. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Two physical phantoms were constructed and used to validate the presented method. Experimental results demonstrate that (1) electron density can be accurately determined from refractive index decrement through a linear relationship, and (2) the effective atomic number can be explicitly derived from the ratio of the linear attenuation to refractive index decrement using a power function plus a constant. The presented method will provide insight into the technique of material separation and find its use in medical and industrial applications.

  8. Effective atomic numbers, electron densities and kinetic energy released in matter of vitamins for photon interaction

    Science.gov (United States)

    Shantappa, A.; Hanagodimath, S. M.

    2014-01-01

    Effective atomic numbers, electron densities of some vitamins (Retinol, Riboflavin, Niacin, Biotin, Folic acid, Cobalamin, Phylloquinone and Flavonoids) composed of C, H, O, N, Co, P and S have been calculated for total and partial photon interactions by the direct method for energy range 1 keV-100 GeV by using WinXCOM and kinetic energy released in matter (Kerma) relative to air is calculated in energy range of 1 keV-20 MeV. Change in effective atomic number and electron density with energy is calculated for all photon interactions. Variation of photon mass attenuation coefficients with energy are shown graphically only for total photon interaction. It is observed that change in mass attenuation coefficient with composition of different chemicals is very large below 100 keV and moderate between 100 keV and 10 MeV and negligible above 10 MeV. Behaviour of vitamins is almost indistinguishable except biotin and cobalamin because of large range of atomic numbers from 1(H) to 16 (S) and 1(H) to 27(Co) respectively. K a value shows a peak due to the photoelectric effect around K-absorption edge of high- Z constituent of compound for biotin and cobalamin.

  9. Photon mass attenuation coefficients, effective atomic numbers and electron densities of some thermoluminescent dosimetric compounds

    Indian Academy of Sciences (India)

    Shivalinge Gowda; S Krishnaveni; T Yashoda; T K Umesh; Ramakrishna Gowda

    2004-09-01

    Photon mass attenuation coefficients of some thermoluminescent dosimetric (TLD) compounds, such as LiF, CaCO3, CaSO4, CaSO4·2H2O, SrSO4, CdSO4, BaSO4, C4H6BaO4 and 3CdSO4·8H2O were determined at 279.2, 320.07, 514.0, 661.6, 1115.5, 1173.2 and 1332.5 keV in a well-collimated narrow beam good geometry set-up using a high resolution, hyper pure germanium detector. The attenuation coefficient data were then used to compute the effective atomic number and the electron density of TLD compounds. The interpolation of total attenuation cross-sections of photons of energy in elements of atomic number was performed using the logarithmic regression analysis of the data measured by the authors and reported earlier. The best-fit coefficients so obtained in the photon energy range of 279.2 to 320.07 keV, 514.0 to 661.6 keV and 1115.5 to 1332.5 keV by a piece-wise interpolation method were then used to find the effective atomic number and electron density of the compounds. These values are found to be in agreement with other available published values.

  10. Effective atomic number of dental smalt; Numero atomico efetivo do esmalte dentario

    Energy Technology Data Exchange (ETDEWEB)

    Rodas D, J.E.; Nogueira, M.S. [Departamento de Fisica e Matematica da FFCLRP-USP. 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    1998-12-31

    The effective atomic numbers Z are enough utilized for to characterize the interactions of ionizing radiation with matter. Particularly for the Z calculation in biological tissues and/or composed materials we need to know the relationship between the cross sections of the diverse radiations interactions with mattera and the atomic numbers Z of the constituent elements in the tissue or composed material. Normally the cross section by atom {sigma} {sup 2} is proportional to Z{sup m}. The m value depends of the iterative process type and the energy of the incident photons. In the case of the photoelectric interaction, the m vary will vary between 4,698 and 4,799 for energies between 10 to 200 keV. It was verified that constituent elements with high Z (>20) they had a major contribution. The m values for the Compton interation and the coherent scattering were calculated of similar way. Knowing the m values, we calculate the partials Z of a composed material. For the calculation of total Z, we can use alternatives starting from the equivalent atomic number corresponding to the total cross section {sigma} {sup d} tot, mc of the composed material. In this work for the calculation of Z values corresponding to diverse interations, we applied a linear regression at the values of Ln {sigma} {sup a} x LnZ for different energies. In general, to characterize a simulator material of a tissue or composed material we need to know the total Z in function of the photon energy applied to dental smalt increases until some hundreds of keV the partial values of Z owing to photoelectric effect and the coherent scattering this is owing to the smalt has a great concentration of elements with high Z. (Author)

  11. Partial as Well as Total Photon Interaction Effective Atomic Numbers for Some Concretes

    Directory of Open Access Journals (Sweden)

    Tejbir Singh

    2013-08-01

    Full Text Available Photon interaction effective atomic number (Zeff for partial as well as total photon interaction processes has been computed using logarithmic interpolation method for seven different concretes viz. (i Ordinary, (ii Hematite - Serpentine, (iii Ilmenite - Limonite, (iv Basalt - magnetite, (v Ilmenite, (vi Steel - scrap and (vii Steel - magnetite concrete in the wide energy range from 10.0 keV to 100 GeV. It has been concluded that this method has an advantage over the atomic to electronic cross-section ratio method especially for mixtures in the intermediate energy level. However, due to lack of experimental data in the higher energy region, it is difficult to discuss, its validity in these energy regions.

  12. Measurement of atomic number and mass attenuation coefficient in magnesium ferrite

    Indian Academy of Sciences (India)

    R H Kadam; S T Alone; G K Bichile; K M Jadhav

    2007-05-01

    Pure magnesium ferrite sample was prepared by standard ceramic technique and characterized by X-ray diffraction method. XRD pattern revealed that the sample possess single-phase cubic spinel structure. The linear attenuation coefficient (), mass attenuation coefficient (/ρ), total atomic cross-section (tot), total electronic cross-section (ele) and the effective atomic number (eff) were calculated for pure magnesium ferrite (MgFe2O4). The values of -ray mass attenuation coefficient were obtained using a NaI energy selective scintillation counter with radioactive -ray sources having energy 0.36, 0.511, 0.662, 1.17 and 1.28 MeV. The experimentally obtained values of /ρ and eff agreed fairly well with those obtained theoretically.

  13. 2D Homologous Perovskites as Light-Absorbing Materials for Solar Cell Applications.

    Science.gov (United States)

    Cao, Duyen H; Stoumpos, Constantinos C; Farha, Omar K; Hupp, Joseph T; Kanatzidis, Mercouri G

    2015-06-24

    We report on the fabrication and properties of the semiconducting 2D (CH3(CH2)3NH3)2(CH3NH3)(n-1)Pb(n)I(3n+1) (n = 1, 2, 3, and 4) perovskite thin films. The band gaps of the series decrease with increasing n values, from 2.24 eV (CH3(CH2)3NH3)2PbI4 (n = 1) to 1.52 eV CH3NH3PbI3 (n = ∞). The compounds exhibit strong light absorption in the visible region, accompanied by strong photoluminescence at room temperature, rendering them promising light absorbers for photovoltaic applications. Moreover, we find that thin films of the semi-2D perovskites display an ultrahigh surface coverage as a result of the unusual film self-assembly that orients the [Pb(n)I(3n+1)](-) layers perpendicular to the substrates. We have successfully implemented this 2D perovskite family in solid-state solar cells, and obtained an initial power conversion efficiency of 4.02%, featuring an open-circuit voltage (V(oc)) of 929 mV and a short-circuit current density (J(sc)) of 9.42 mA/cm(2) from the n = 3 compound. This result is even more encouraging considering that the device retains its performance after long exposure to a high-humidity environment. Overall, the homologous 2D halide perovskites define a promising class of stable and efficient light-absorbing materials for solid-state photovoltaics and other applications.

  14. The effective atomic number for gamma ray interactions with heavy metal oxide glasses

    DEFF Research Database (Denmark)

    Manohara, S. R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    The effective atomic number, Z(eff), and the effective electron density, N-el,N-eff, have been calculated at photon energies from 1 keV to 100 GeV for CaO-SrO-B2O3, ZnO-PbO-B2O3, and CdO-PbO-B2O3 glasses with potential applications as gamma ray shielding materials. Appreciable variations are noted...... glasses have gamma ray shielding properties comparable with standard shielding materials, such as concrete....

  15. Studies on effective atomic number, electron density and kerma for some fatty acids and carbohydrates

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2008-01-01

    The effective atomic number, Z(eff), the effective electron density, N-el, and kerma have been calculated for some fatty acids and carbohydrates for photon interaction in the extended energy range from 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the Win....... The minimum values of Z(eff) and N-el are found at intermediate energies, typically 0.05 MeV bio-molecule. Wherever possible, the calculations are compared with experimental results. A comparison...

  16. Systematic measurements of opacity dependence on temperature, density, and atomic number at stellar interior conditions

    Science.gov (United States)

    Bailey, James; Nagayama, T.; Loisel, G. P.; Rochau, G. A.; Blancard, C.; Colgan, J.; Cosse, Ph.; Faussurier, G.; Fontes, C. J.; Golovkin, I.; Hansen, S. B.; Iglesias, C. A.; Kilcrease, D. P.; Macfarlane, J. J.; Mancini, R. C.; Nahar, S. N.; Orban, C.; Pradhan, A. K.; Sherrill, M.; Wilson, B. G.; Pain, J. C.; Gilleron, F.

    2016-10-01

    Model predictions for iron opacity are notably different from measurements performed at conditions similar to the boundary between the solar radiation and convection zone. New measurements at the Sandia Z facility with chromium, iron, and nickel are providing a systematic study of how opacity changes with temperature, density, and atomic number. These measurements help further evaluate possibilities for experiment errors and help constrain hypotheses for opacity model refinements. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

  17. Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Yongchun; WANG; Shijie; FENG; Junming; LI; Chunlai; OUYANG; Ziyuan; LIU; Jianzhong; LI; Xiaobiao

    2006-01-01

    Electromagnetic (EM) parameters (ε', ε″,μ', μ″ ) of several M2+Fe2O4 and Fe2O3 type natural ferrites with different geological occurrences are measured in this paper. The measurement results show that EM parameters of a magmatic-occurring natural ferrite is very different from other types occurring from sedimentary-metamorphic iron deposit, hydrothermal vein iron deposit, outer contact of magmatic iron deposit. It has potential to be used as magnetic absorbent in microwave absorbing materials. After mineral separation and concentration, this magmatic-occurring natural ferrite was processed into type A ferrite absorbent. Type A natural ferrite absorbent is a kind of magnetic material with low dielectric constants, high magnetic conductivity and high EM loss. Its EM parameters areε' = 58.60, ε″ = 10.0, μ' = 1.2-1.5, μ″ = 1.0-1.2, respectively. In order to illuminate the regulation mechanism of EM parameters, we studied the chemical and mineral composition of type A ferrite absorbent. There is high concentration of natural impurities, which regulate the EM parameters of type A ferrite greatly. For comparison, the other types of natural ferrite, single-phase magnetite and two-phase iron minerals (ilmenite and magnetite), have few impurity. Thus regulation mechanism of EM parameters was absent in these ferrites. As a result, the regulation of EM parameters is advantageous to develop type A natural ferrite as excellent absorbent, lowers the reflectivity coefficients and enhances the absorbing efficiency of MAM made from it. Furthermore, the impurities in type A natural ferrite and its effects on EM parameters are very difficult to simulate in the synthesize ferrite. The carbonyl-iron powder is another kind of absorbent that is used extensively in MAM. To compare the absorbing properties of these two absorbent, type A natural ferrite and carbonyl-iron powder were mixed with rubber and processed into microwave absorbing sheets with the same procedures and

  18. Coupling Hollow Fe3O4-Fe Nanoparticles with Graphene Sheets for High-Performance Electromagnetic Wave Absorbing Material.

    Science.gov (United States)

    Qu, Bin; Zhu, Chunling; Li, Chunyan; Zhang, Xitian; Chen, Yujin

    2016-02-17

    We developed a strategy for coupling hollow Fe3O4-Fe nanoparticles with graphene sheets for high-performance electromagnetic wave absorbing material. The hollow Fe3O4-Fe nanoparticles with average diameter and shell thickness of 20 and 8 nm, respectively, were uniformly anchored on the graphene sheets without obvious aggregation. The minimal reflection loss RL values of the composite could reach -30 dB at the absorber thickness ranging from 2.0 to 5.0 mm, greatly superior to the solid Fe3O4-Fe/G composite and most magnetic EM wave absorbing materials recently reported. Moreover, the addition amount of the composite into paraffin matrix was only 18 wt %.

  19. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  20. Concept of effective atomic number and effective mass density in dual-energy X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bonnin, Anne, E-mail: annebonnin@free.fr [ESRF, 6 Jules Horowitz, F-38073 Grenoble Cedex (France); LVA, Vibrations and Acoustic Laboratory, INSA-Lyon, Université de Lyon, F-69621 Villeurbanne Cedex (France); Duvauchelle, Philippe, E-mail: philippe.duvauchelle@insa-lyon.fr [LVA, Vibrations and Acoustic Laboratory, INSA-Lyon, Université de Lyon, F-69621 Villeurbanne Cedex (France); Kaftandjian, Valérie [LVA, Vibrations and Acoustic Laboratory, INSA-Lyon, Université de Lyon, F-69621 Villeurbanne Cedex (France); Ponard, Pascal [Thales Electron Devices SAS, 2 Rue Marcel Dassault, BP23 78141 Vélizy, Villacoublay Cedex (France)

    2014-01-01

    This paper focuses on dual-energy X-ray computed tomography and especially the decomposition of the measured attenuation coefficient in a mass density and atomic number basis. In particular, the concept of effective atomic number is discussed. Although the atomic number is well defined for chemical elements, the definition of an effective atomic number for any compound is not an easy task. After reviewing different definitions available in literature, a definition related to the method of measurement and X-ray energy, is suggested. A new concept of effective mass density is then introduced in order to characterize material from dual-energy computed tomography. Finally, this new concept and definition are applied on a simulated case, focusing on explosives identification in luggage.

  1. Correction: Number density distribution of solvent molecules on a substrate: a transform theory for atomic force microscopy.

    Science.gov (United States)

    Amano, Ken-Ichi; Liang, Yunfeng; Miyazawa, Keisuke; Kobayashi, Kazuya; Hashimoto, Kota; Fukami, Kazuhiro; Nishi, Naoya; Sakka, Tetsuo; Onishi, Hiroshi; Fukuma, Takeshi

    2016-08-07

    Correction for 'Number density distribution of solvent molecules on a substrate: a transform theory for atomic force microscopy' by Ken-ichi Amano et al., Phys. Chem. Chem. Phys., 2016, 18, 15534-15544.

  2. Mass attenuation coefficients and effective atomic numbers of biological compounds for gamma ray interactions

    Science.gov (United States)

    Gaikwad, Dhammajyot Kundlik; Pawar, Pravina P.; Selvam, T. Palani

    2017-09-01

    The mass attenuation coefficients (μ/ρ) for some enzymes, proteins, amino acids and fatty acids were measured at 122, 356, 511, 662, 1170, 1275 and 1330 keV photon energies, by performing transmission experiments using 57Co, 133Ba, 137Cs, 60Co and 22Na sources collimated to produce 0.52 cm diameter beams. A NaI (Tl) scintillation detector with energy resolution 8.2% at 663 keV was used for detection. The experimental values of (μ/ρ) were then used to determine the atomic cross section (σa), electronic cross section (σe), effective atomic number (Zeff) and electron density (Neff). It was observed that (μ/ρ), σa and σe decrease initially and then tends to be almost constant at higher energies. Values of Zeff and Neff were observed roughly constant with energy. The deviations in experimental results of radiological parameters were believed to be affected by physical and chemical environments. Experimental results of radiological parameters were observed in good agreement with WinXCom values.

  3. Study of Effective Atomic Number in Compounds Using Gamma-Ray Interaction

    Science.gov (United States)

    Rudraswamy, B.; Dhananjaya, N.

    2009-03-01

    In view of low cost, hydrogenous materials such as Polyethylene and CH2 have been developed and being used currently by NASA as an effective galactic cosmic radiation shields in place of aluminum for hull design of spacecraft. Lead, steel and concrete which are currently being used as effective radiation shields for the treatment of rooms equipped with Electron accelerators are found be quite expensive. Hence, it is necessary to use alternative low cost material which serves as an effective radiation shield. In the present study, an attempt has been made to measure gamma-ray mass attenuation coefficient, effective atomic number and absorbed dose rate of the compounds such as NH4Cl, KCl, and CdO using various gamma sources of energies 356, 511, 662, 1173, and 1332 keV. These parameters are expected to gives vital information on the selection of shielding materials.

  4. Dopant Concentration and Effective Atomic Number of Copper-Doped Potassium Borate Glasses

    Directory of Open Access Journals (Sweden)

    I. Hossain

    2013-01-01

    Full Text Available Copper-doped (0.5 mol% and undoped potassium borate glasses have been prepared by the composition of (100-xH3BO3 + xK2CO3, where 10 ≤ x ≤ 30 mol % by the traditional melting quenching method. The structural pattern of glasses with different composition has been identified by X-ray diffraction (XRD. The glow curves were analysed to determine various characterizations of the TLDs. Identification of the compositions and concentrations and effective atomic number of undoped and doped potassium borate glass was carried out using scanning electron microscope analysis (SEM. The dopant concentrations are found to be 0.25 mol%, while Zeff are 11.42 and 10.48 for Cu-doped and undoped potassium borate glasses, respectively.

  5. Effective atomic number, electron density and kerma of gamma radiation for oxides of lanthanides

    Indian Academy of Sciences (India)

    R S Niranjan; B Rudraswamy; N Dhananjaya

    2012-03-01

    An attempt has been made to estimate the effective atomic number, electron density (0.001 to 105 MeV) and kerma (0.001 to 20 MeV) of gamma radiation for a wide range of oxides of lanthanides using mass attenuation coefficient from WinXCom and mass energy absorption coefficient from Hubbell and Seltzer. The values of these parameters have been found to change with energy for different oxides of lanthanides. The lanthanide oxides find remarkable applications in the field of medicine, biology, nuclear engineering and space technology. Nano-oxides of lanthanide find applications in display and lighting industry.

  6. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    Science.gov (United States)

    Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90° ( x=0.99 Å -1). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number ( Zeff) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Zeff of breast tissues, which are mainly related to the elemental composition of carbon ( Z=6) and oxygen ( Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  7. Negative differential resistance in a one-dimensional molecular wire with odd number of atoms

    Indian Academy of Sciences (India)

    S Lakshmi; Swapan K Pati

    2005-10-01

    We have investigated the effects of electron{phonon coupling on the current-voltage characteristics of a one-dimensional molecular wire with odd number of atoms. The wire has been modelled using the Su-Schreiffer-Heeger (SSH) Hamiltonian and the current{voltage characteristics have been obtained using the Landauer's formalism. In the presence of strong electron-lattice coupling, we find that there are regions of negative differential resistance (NDR) at some critical bias, due to the degeneracy in the energies of the frontier molecular orbitals. The presence of the applied bias and the electron{lattice coupling results in the delocalization of these low-lying molecular states leading to the NDR behaviour.

  8. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    Energy Technology Data Exchange (ETDEWEB)

    Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90{sup o} (x=0.99 A{sup -1}). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z{sub eff} of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  9. Absolute number densities of helium metastable atoms determined by atomic absorption spectroscopy in helium plasma-based discharges used as ambient desorption/ionization sources for mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reininger, Charlotte; Woodfield, Kellie [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States); Keelor, Joel D.; Kaylor, Adam; Fernández, Facundo M. [Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA 30332 (United States); Farnsworth, Paul B., E-mail: paul_farnsworth@byu.edu [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States)

    2014-10-01

    The absolute number densities of helium atoms in the 2s {sup 3}S{sub 1} metastable state were determined in four plasma-based ambient desorption/ionization sources by atomic absorption spectroscopy. The plasmas included a high-frequency dielectric barrier discharge (HF-DBD), a low temperature plasma (LTP), and two atmospheric-pressure glow discharges, one with AC excitation and the other with DC excitation. Peak densities in the luminous plumes downstream from the discharge capillaries of the HF-DBD and the LTP were 1.39 × 10{sup 12} cm{sup −3} and 0.011 × 10{sup 12} cm{sup −3}, respectively. Neither glow discharge produced a visible afterglow, and no metastable atoms were detected downstream from the capillary exits. However, densities of 0.58 × 10{sup 12} cm{sup −3} and 0.97 × 10{sup 12} cm{sup −3} were measured in the interelectrode regions of the AC and DC glow discharges, respectively. Time-resolved measurements of metastable atom densities revealed significant random variations in the timing of pulsed absorption signals with respect to the voltage waveforms applied to the discharges. - Highlights: • We determine He metastable number densities for four plasma types • The highest number densities were observed in a dielectric barrier discharge • No helium metastable atoms were observed downstream from the exits of glow discharges.

  10. Mechanical properties of cancer cells depend on number of passages: Atomic force microscopy indentation study

    Science.gov (United States)

    Dokukin, Maxim E.; Guz, Natalia V.; Sokolov, Igor

    2017-08-01

    Here we investigate one of the key questions in cell biology, if the properties of cell lines depend on the number of passages in-vitro. It is generally assumed that the change of cell properties (phenotypic drift) is insignificant when the number of passages is low (<10) the changes were reported for passages higher than 30-40. We used quantitative indentation models to extract information on the elastic modulus of the cell body and parameters of the pericellular brush layer from indentation force curves, which are recorded by means of atomic force microscopy (AFM). Using this method, we tested the change of the cell properties of human cancer breast epithelial cell line, MCF-7 (ATCC® HTB-22™), within the passages between 2 and 10. In contrast to the previous expectations, we observed a substantial transient change of the elastic modulus of the cell body during the first four passages (up to 4 times). The changes in the parameters of the pericellular coat were less dramatic (up to 2 times) but still statistically significant.

  11. A probable vacuum state containing a large number of hydrogen atom of excited state or ground state K, Rb or Cs atom

    CERN Document Server

    You, Pei-Lin

    2008-01-01

    The linear Stark effect shows that the first excited state of hydrogen atom has large permanent electric dipole moment (EDM), d(H)=3eao (ao is Bohr radius). Using special capacitors our experiments discovered that the ground state K, Rb or Cs atom is polar atom with a large EDM of the order of eao as hydrogen atom of excited state. Their capacitance(C) at different voltage (V) was measured. The C-V curve shows that the saturation polarization of K, Rb or Cs vapor has be observed when the field E more than ten to the fifth power V/m. When the saturation polarization appeared, nearly all K, Rb or Cs atoms(more than 98 percent) turned toward the direction of the field, and C is approximately equal to Co (Co is vacuum capacitance) or their dielectric constant is nearly the same as vacuum! K, Rb or Cs vapor just exist in the lowest energy state, so we see the vacuum state containing a large number of atoms! Due to the saturation polarization of hydrogen vapor of excited state is easily appears, we conjecture that ...

  12. Number density distribution of solvent molecules on a substrate: a transform theory for atomic force microscopy.

    Science.gov (United States)

    Amano, Ken-Ichi; Liang, Yunfeng; Miyazawa, Keisuke; Kobayashi, Kazuya; Hashimoto, Kota; Fukami, Kazuhiro; Nishi, Naoya; Sakka, Tetsuo; Onishi, Hiroshi; Fukuma, Takeshi

    2016-06-21

    Atomic force microscopy (AFM) in liquids can measure a force curve between a probe and a buried substrate. The shape of the measured force curve is related to hydration structure on the substrate. However, until now, there has been no practical theory that can transform the force curve into the hydration structure, because treatment of the liquid confined between the probe and the substrate is a difficult problem. Here, we propose a robust and practical transform theory, which can generate the number density distribution of solvent molecules on a substrate from the force curve. As an example, we analyzed a force curve measured by using our high-resolution AFM with a newly fabricated ultrashort cantilever. It is demonstrated that the hydration structure on muscovite mica (001) surface can be reproduced from the force curve by using the transform theory. The transform theory will enhance AFM's ability and support structural analyses of solid/liquid interfaces. By using the transform theory, the effective diameter of a real probe apex is also obtained. This result will be important for designing a model probe of molecular scale simulations.

  13. Studies on effective atomic numbers and electron densities of nucleobases in DNA

    Science.gov (United States)

    Kumar, Ashok

    2016-10-01

    Various parameters of dosimetric importance such as effective atomic numbers (Zeff) and electron densities (Nel) of nucleobases in DNA have been calculated for the total and partial photon interaction processes in the wide energy range of 1 keV-100 GeV. The variations of Zeff and Nel with energy are shown graphically for all partial and total interaction processes and are found to be similar. Up to 10 keV, Zeff and Nel show a sharp increase for cytosine-guanine and thymine-adenine whereas for all the other nucleobases, it is almost constant. Then there is sharp decrease in Zeff and Nel with energy up to 100 keV for all the nucleobases. From 100 keV to 6 MeV, Zeff and Nel are almost independent of energy. From 6 MeV to 100 MeV, there is regular increase in Zeff and Nel with photon energy. Above 400 MeV, Zeff and Nel remain almost constant. The obtained results are due to the dominance of photoelectric absorption, Compton scattering and pair production in different energy regions as respectively stated above and their dependences on the chemical compositions of the interacting media.

  14. Standard specification for boron-Based neutron absorbing material systems for use in nuclear spent fuel storage racks

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This specification defines criteria for boron-based neutron absorbing material systems used in racks in a pool environment for storage of nuclear light water reactor (LWR) spent-fuel assemblies or disassembled components to maintain sub-criticality in the storage rack system. 1.2 Boron-based neutron absorbing material systems normally consist of metallic boron or a chemical compound containing boron (for example, boron carbide, B4C) supported by a matrix of aluminum, steel, or other materials. 1.3 In a boron-based absorber, neutron absorption occurs primarily by the boron-10 isotope that is present in natural boron to the extent of 18.3 ± 0.2 % by weight (depending upon the geological origin of the boron). Boron, enriched in boron-10 could also be used. 1.4 The materials systems described herein shall be functional – that is always be capable to maintain a B10 areal density such that subcriticality Keff <0.95 or Keff <0.98 or Keff < 1.0 depending on the design specification for the service...

  15. Microstructural Characterization of Burnable Absorber Materials Being Evaluated for Application in LEU U-Mo Fuel Plates

    Energy Technology Data Exchange (ETDEWEB)

    J. F. Jue; B. Miller; B. Yao; E. Perez; Y. H. Sohn

    2011-03-01

    The starting microstructure of a fuel plate will impact how it performs during irradiation. As a result, microstructural characterization has been performed on as-fabricated monolithic fuel plates to determine the changes in fuel plate microstructure that may result from changes in fabrication parameters. Particular focus has been given to the fuel plate U-10Mo/Zr and Zr/AA6061 cladding interfaces, since the integrity of these interfaces will play a big role in determining the overall performance of the fuel plate during irradiation. In addition, burnable absorber materials for potential incorporation into monolithic fuel plates have been characterized to identify their as-fabricated microstructures. This information will be important when trying to understand the PIE data from fuel plates with burnable absorbers that are irradiated in future irradiation experiments. This paper will focus on the microstructures observed using optical metallography, X-ray diffraction, and scanning and transmission electron microscopy for monolithic fuel plates exposed to different fabrication parameters and for as-fabricated burnable absorber materials.

  16. The influence of basic composition and microstructures on the properties of Ni–Zn ferrite radio-absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.G., E-mail: ilem58@mail.ru; Menshova, S.B.; Klimov, A.N.; Vergazov, R.M.

    2015-11-01

    This work deals with the research into the electromagnetic properties of Ni–Zn ferrite radio-absorbing materials obtained by the ceramic method under different technological conditions. There has been ascertained the influence of basic composition and microstructures on the level of absorption of electromagnetic radiation by Ni–Zn ferrite radio-absorbing materials. The results indicate that increasing the surplus Fe{sub 2}O{sub 3} up to 51.0 mol% leads to a shift in frequency interval in the direction of low frequencies. It can be explained by increase of the permeability and permittivity of a ferrite. - Highlights: • Increasing Fe{sub 2}O{sub 3} up to 51.0 mol% leads to increasing permeability of a ferrite. • It also leads to a shift in frequency interval in the direction of low frequencies. • It is more effective to introduce Fe{sub 2}O{sub 3} at the second stage of the crushing.

  17. Atomic Theory and Multiple Combining Proportions: The Search for Whole Number Ratios.

    Science.gov (United States)

    Usselman, Melvyn C; Brown, Todd A

    2015-04-01

    John Dalton's atomic theory, with its postulate of compound formation through atom-to-atom combination, brought a new perspective to weight relationships in chemical reactions. A presumed one-to-one combination of atoms A and B to form a simple compound AB allowed Dalton to construct his first table of relative atomic weights from literature analyses of appropriate binary compounds. For such simple binary compounds, the atomic theory had little advantages over affinity theory as an explanation of fixed proportions by weight. For ternary compounds of the form AB2, however, atomic theory made quantitative predictions that were not deducible from affinity theory. Atomic theory required that the weight of B in the compound AB2 be exactly twice that in the compound AB. Dalton, Thomas Thomson and William Hyde Wollaston all published within a few years of each other experimental data that claimed to give the predicted results with the required accuracy. There are nonetheless several experimental barriers to obtaining the desired integral multiple proportions. In this paper I will discuss replication experiments which demonstrate that only Wollaston's results are experimentally reliable. It is likely that such replicability explains why Wollaston's experiments were so influential.

  18. An Estimation of the Number and Size of Atoms in a Printed Period

    Science.gov (United States)

    Schaefer, Beth; Collett, Edward; Tabor-Morris, Anne; Croman, Joseph

    2011-01-01

    Elementary school students learn that atoms are very, very small. Students are also taught that atoms (and molecules) are the fundamental constituents of the material world. Numerical values of their size are often given, but, nevertheless, it is difficult to imagine their size relative to one's everyday surroundings. In order for students to…

  19. Revision of single atom local density and capture number varying with coverage in uniform depletion approximation and its effect on coalescence and number of stable clusters

    Institute of Scientific and Technical Information of China (English)

    Shao Qing-Yi; Zhang Juan

    2011-01-01

    In vapour deposition,single atoms(adatoms)on the substrate surface are the main source of growth.The change in its density plays a decisive role in the growth of thin films and quantum size islands.In the nucleation and cluster coalescence stages of vapour deposition,the growth of stable clusters occurs on the substrate surface covered by stable clusters.Nucleation occurs in the non-covered part,while the total area covered by stable clusters on the substrate surface will gradually increase.Carefully taking into account the coverage effect,a revised single atom density rate equation is given for the famous and widely used thin-film rate equation theory,but the work of solving the revised equation has not been done.In this paper,we solve the equation and obtain the single-atom density and capture number by using a uniform depletion approximation.We determine that the single atom density is much lower than that evaluated from the single atom density rate equation in the traditional rate equation theory when the stable cluster coverage fraction is large,and it goes down very fast with an increase in the coverage fraction.The revised equation gives a higher value for the 'average' capture number than the present equation. It also increases with increasing coverage.That makes the preparation of single crystalline thin film materials difficult and the size control of quantum size islands complicated.We also discuss the effect of the revision on coalescence and the number of stable clusters in vapour deposition.

  20. The effective atomic number revisited in the light of modern photon-interaction cross-section databases

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Thind, K. S.

    2010-01-01

    The effective atomic number, Z(eff), has been calculated for fatty acids and cysteine. It is shown that Z(eff) is a useful parameter for low-Z materials at any energy above 1 key. Absorption edges of medium-Z elements may complicate the energy dependence of Z(eff) below 10 key. The notion of Z(ef...

  1. Absolute measurement of the effective atomic number and the electron density by using dual-energy CT images

    Science.gov (United States)

    Kim, Dae-Hong; Lee, Won-Hyung; Jeon, Sung-Soo; Kim, Hee-Joung

    2012-12-01

    Material decomposition using dual-energy and material-selective techniques was performed using computed-tomography (CT)-generated reconstructed images. Previous work using the dual-energy method focused on extracting the effective atomic number and the electron density of materials to confirm the dosimetric accuracy in radiation therapy. Dual-energy methods mostly depend on the device generating the X-rays, such as a synchrotron, and on dose verification for radiation treatment planning. Information obtained from CT imaging is important both in diagnosis and in planning radiation therapy. In a clinical setting, CT images are usually displayed as Houndsfield units (HU), which are extracted from the attenuation coefficient of a material. The attenuation coefficient is calculated using the effective atomic number and the electron density of a material; thus, information expressed in HU can be converted into the effective atomic number and the electron density by using the dual-energy equation. This study was performed using realistic Xray spectra to differentiate between the contrast media and plaque in vascular images. Our results suggest that the effective atomic number and electron density are useful in distinguishing between two adjacent materials with similar HUs.

  2. Evaluation of the acoustic and non-acoustic properties of sound absorbing materials using a three-microphone impedance tube

    CERN Document Server

    Doutres, Olivier; Atalla, Noureddine; Panneton, Raymond; 10.1016/j.apacoust.2010.01.007

    2010-01-01

    This paper presents a straightforward application of an indirect method based on a three-microphone impedance tube setup to determine the non-acoustic properties of a sound absorbing porous material. First, a three-microphone impedance tube technique is used to measure some acoustic properties of the material (i.e., sound absorption coefficient, sound transmission loss, effective density and effective bulk modulus) regarded here as an equivalent fluid. Second, an indirect characterization allows one to extract its non-acoustic properties (i.e., static airflow resistivity, tortuosity, viscous and thermal characteristic lengths) from the measured effective properties and the material open porosity. The procedure is applied to four different sound absorbing materials and results of the characterization are compared with existing direct and inverse methods. Predictions of the acoustic behavior using an equivalent fluid model and the found non-acoustic properties are in good agreement with impedance tube measureme...

  3. Electromagnetic behavior of radar absorbing materials based on Ca hexaferrite modified with Co-Ti ions and doped with La

    Directory of Open Access Journals (Sweden)

    Valdirene Aparecida da Silva

    2009-06-01

    Full Text Available Radar Absorbing Materials (RAM are compounds that absorb incidental electromagnetic radiation in tuned frequencies and dissipate it as heat. Its preparation involves the adequate processing of polymeric matrices filled with compounds that act as radar absorbing centers in the microwave range. This work shows the electromagnetic evaluation of RAM based on CoTi and La doped Ca hexaferrite. Vibrating Sample Magnetization analyses show that ion substitution promoted low values for the parameters of saturation magnetization (123.65 Am2/kg and coercive field (0.07 T indicating ferrite softening. RAM samples obtained using different hexaferrite concentrations (40-80 per cent, w/w show variations in complex permeability and permittivity parameters and also in the performance of incidental radiation attenuation. Microwave attenuation values between 40 and 98 per cent were obtained.

  4. Absolute number densities of helium metastable atoms determined by atomic absorption spectroscopy in helium plasma-based discharges used as ambient desorption/ionization sources for mass spectrometry

    Science.gov (United States)

    Reininger, Charlotte; Woodfield, Kellie; Keelor, Joel D.; Kaylor, Adam; Fernández, Facundo M.; Farnsworth, Paul B.

    2014-10-01

    The absolute number densities of helium atoms in the 2s 3S1 metastable state were determined in four plasma-based ambient desorption/ionization sources by atomic absorption spectroscopy. The plasmas included a high-frequency dielectric barrier discharge (HF-DBD), a low temperature plasma (LTP), and two atmospheric-pressure glow discharges, one with AC excitation and the other with DC excitation. Peak densities in the luminous plumes downstream from the discharge capillaries of the HF-DBD and the LTP were 1.39 × 1012 cm- 3 and 0.011 × 1012 cm- 3, respectively. Neither glow discharge produced a visible afterglow, and no metastable atoms were detected downstream from the capillary exits. However, densities of 0.58 × 1012 cm- 3 and 0.97 × 1012 cm- 3 were measured in the interelectrode regions of the AC and DC glow discharges, respectively. Time-resolved measurements of metastable atom densities revealed significant random variations in the timing of pulsed absorption signals with respect to the voltage waveforms applied to the discharges.

  5. On the Prediction of the Nonlinear Absorption in Reverse Saturable Absorbing Materials

    Science.gov (United States)

    Pachter, Ruth; Nguyen, Kiet A.; Day, Paul N.; Kennel, Joshua C.

    2001-03-01

    In our continuing efforts to design materials that exhibit reverse saturable absorption (RSA), we systematically examine the ability of the time-dependent density functional theory (TDDFT) method using local, nonlocal, and hybrid functionals, to predict the experimental nonlinear absorption for a variety of organic and organometallic molecular systems, including a number of free-base porphyrins, phthalocyanine and their metal complexes. The ground and triplet-triplet excitation energies, as well as the oscillator strengths are calculated, indicating good agreement with experiment. We conclude that the TDDFT approach with a hybrid functional provides good estimates for the nonlinear absorption of RSA materials.

  6. 吸波材料反射率的现场测量方法%The Measurement Method for Absorbing Material Relfectivity on the Spot

    Institute of Scientific and Technical Information of China (English)

    杨金涛; 马永光; 尚柱冈

    2014-01-01

    通过对微波暗室中安装在墙壁上的吸波材料反射率的现场测量方法的研究,采用矢量网络分析仪对吸波材料反射率进行现场测量时,利用时域门技术来减小暗室现场对吸波材料反射率测量的影响,通过比较标准金属板和吸波材料的测量值得到吸波材料的反射率。%This paper is about the study on the spot measurement method reflectivity of absorbing material installed on the wall of microwave chamber. The vector network analyzer which is to measure the absorbing material reflectivity on the spot is adopted. The time-domain gate technology is used to reduce the influence of the microwave chamber to absorbing material. Through comparing the measuring value of the standard metal plate and absorbing material, the reflectivity of the absorbing material is obtained.

  7. Combining configuration interaction with perturbation theory for atoms with large number of valence electrons

    CERN Document Server

    Dzuba, V A; Harabati, C; Flambaum, V V

    2016-01-01

    A version of the configuration interaction (CI) method is developed which treats highly excited many-electron basis states perturbatively, so that their inclusion does not affect the size of the CI matrix. This removes, at least in principle, the main limitation of the CI method in dealing with many-electron atoms or ions. We perform calculations of the spectra of iodine and its ions, tungsten, and ytterbium as examples of atoms with open $s$, $p$, $d$ and $f$-shells. Good agreement of the calculated data with experiment illustrates the power of the method. Its advantages and limitations are discussed.

  8. A new method to measure electron density and effective atomic number using dual-energy CT images

    Science.gov (United States)

    Ramos Garcia, Luis Isaac; Pérez Azorin, José Fernando; Almansa, Julio F.

    2016-01-01

    The purpose of this work is to present a new method to extract the electron density ({ρ\\text{e}} ) and the effective atomic number (Z eff) from dual-energy CT images, based on a Karhunen-Loeve expansion (KLE) of the atomic cross section per electron. This method was used to calibrate a Siemens Definition CT using the CIRS phantom. The predicted electron density and effective atomic number using 80 kVp and 140 kVp were compared with a calibration phantom and an independent set of samples. The mean absolute deviations between the theoretical and calculated values for all the samples were 1.7 %  ±  0.1 % for {ρ\\text{e}} and 4.1 %  ±  0.3 % for Z eff. Finally, these results were compared with other stoichiometric method. The application of the KLE to represent the atomic cross section per electron is a promising method for calculating {ρ\\text{e}} and Z eff using dual-energy CT images.

  9. Determination of atomic number and composition of human enamel; Determinacao da composicao e numero atomico efetivo do esmalte humano

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, M.S. [Centro Regional de Ciencias Nucleares (CRCN), Recife, PE (Brazil); Rodas Duran, J.E. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2001-07-01

    The teeth are organs of complicated structure that consist, partly, of hard tissue containing in its interior the dental pulp, rich in vases and nerves. The main mass of the tooth is constituted by the dentine, which is covered with hard tissues and of epithelial origin called enamel. The dentine of the human teeth used in this work were completely removed and the teeth were cut with a device with a diamond disc. In this work the chemical composition of the human enamel was determined, which showed a high percentage of Ca and P, in agreement with the results found in the literature. The effective atomic number of the material and the half-value layer in the energy range of diagnostic X-ray beams were determined. Teeth could be used to evaluated the public's individual doses as well as for retrospective dosimetry what confirms the importance of their effective atomic number and composition determination. (author)

  10. Dependence of microwave absorption properties on ferrite volume fraction in MnZn ferrite/rubber radar absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Gama, Adriana M., E-mail: adrianaamg@iae.cta.br [Divisao de Materiais (AMR), Instituto de Aeronautica e Espaco (IAE), Departamento de Ciencia e Tecnologia Aeroespacial - DCTA (Brazil); Rezende, Mirabel C., E-mail: mirabelmcr@iae.cta.br [Divisao de Materiais (AMR), Instituto de Aeronautica e Espaco (IAE), Departamento de Ciencia e Tecnologia Aeroespacial - DCTA (Brazil); Dantas, Christine C., E-mail: christineccd@iae.cta.br [Divisao de Materiais (AMR), Instituto de Aeronautica e Espaco (IAE), Departamento de Ciencia e Tecnologia Aeroespacial - DCTA (Brazil)

    2011-11-15

    We report the analysis of measurements of the complex magnetic permeability ({mu}{sub r}) and dielectric permittivity ({epsilon}{sub r}) spectra of a rubber radar absorbing material (RAM) with various MnZn ferrite volume fractions. The transmission/reflection measurements were carried out in a vector network analyzer. Optimum conditions for the maximum microwave absorption were determined by substituting the complex permeability and permittivity in the impedance matching equation. Both the MnZn ferrite content and the RAM thickness effects on the microwave absorption properties, in the frequency range of 2-18 GHz, were evaluated. The results show that the complex permeability and permittivity spectra of the RAM increase directly with the ferrite volume fraction. Reflection loss calculations by the impedance matching degree (reflection coefficient) show the dependence of this parameter on both thickness and composition of RAM. - Highlights: > Permeability and permittivity spectra of a MnZn ferrite RAM (2-18 GHz) are given. > Higher MnZn volume fraction favors increase of RAM/'s permeability and permittivity. > Minimum RL as a function of frequency, thickness and MnZn volume fraction given. > Higher thicknesses imply better absorption; optimum band shifts to lower frequencies. > For higher volume fractions, smaller thickness might offer better absorption (>10 GHz).

  11. Reduced-graphene-oxide-and-strontium-titanate-based double-layered composite: an efficient microwave-absorbing material

    Indian Academy of Sciences (India)

    SUKANTA DAS; S K SAHU; RAMESH ORAON; P C ROUTRAY; H BASKEY; G C NAYAK

    2017-04-01

    Microwave-absorbing materials based on reduced graphene oxide (r-GO)/ strontium titanate were prepared by embedding in epoxy matrix. R-GO and strontium titanate were synthesized and characterized before composite fabrication. Microstructures of the constituent elements were studied by scanning electron microscopy and X-ray diffraction (XRD). Microwave absorption capabilities of the composite absorbers were investigated using a Vector Network Analyser in the range 8–12 GHz. A maximum reflection loss of $−$7.5 and $−$16.4 dB was obtained at 9.3 and 12.08 GHz, respectively, for 2% (w/w) r-GO-loaded epoxy composites. A maximum attenuation of $−$12.8 dB at 9.3 GHz was obtained for the strontium titanate/epoxy composite. However, double-layer composite with r-GO/strontium titanate/epoxy composition showed the maximum reflection loss of $−$15.1 dB at 9.47 GHz and $−$9.65 dB at 12.3 GHz. All the results are discussed in terms of complex permeability and permittivity. The study revealed that intrinsic conductivity and polarization of the r-GO particles and dielectric polarization of the strontium titanate within epoxy matrix contribute to the microwave absorption.

  12. Optical property of SmAlO3 applied as 1.06μm laser absorbing material

    Institute of Scientific and Technical Information of China (English)

    朱怡青; 韩朋德; 张乐; 王丽熙; 张其土

    2013-01-01

    SmAlO3 powders were successfully synthesized through the citrate sol-gel combustion method. The phase evolution of the prepared powders were characterized using thermal gravimetric (TG) analysis, differential scanning calorimetry (DSC) analysis and Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) was applied to examine the purity of the powders. The re-flective properties of SmAlO3 with changing temperatures were investigated by ultraviolet-visible near-infrared spectrophotometer (UVPC) specular reflection spectrum. The results displayed that pure SmAlO3 phase with preferable reflectivity at 1.06μm could be obtained at 900 ºC for 2 h. Furthermore, the reflectivity of SmAlO3 at various temperatures from-40 to 500 ºC transformed within ±0.1%, and all maintained below 1%at 1.06μm. The absorbance of SmAlO3 in the resin solution was 2.134 and the moral absorption coefficient was about 384.8 in the work. The study indicated that SmAlO3 powders may be a promising kind of heat resistant absorb-ing material for 1.06μm laser defense, which could be further applied to laser absorbing coatings with a wide range of temperatures.

  13. Two-Dimensional SnO Anodes with a Tunable Number of Atomic Layers for Sodium Ion Batteries

    KAUST Repository

    Zhang, Fan

    2017-01-18

    We have systematically changed the number of atomic layers stacked in 2D SnO nanosheet anodes and studied their sodium ion battery (SIB) performance. The results indicate that as the number of atomic SnO layers in a sheet decreases, both the capacity and cycling stability of the Na ion battery improve. The thinnest SnO nanosheet anodes (two to six SnO monolayers) exhibited the best performance. Specifically, an initial discharge and charge capacity of 1072 and 848 mAh g-1 were observed, respectively, at 0.1 A g-1. In addition, an impressive reversible capacity of 665 mAh g-1 after 100 cycles at 0.1 A g-1 and 452 mAh g-1 after 1000 cycles at a high current density of 1.0 A g-1 was observed, with excellent rate performance. As the average number of atomic layers in the anode sheets increased, the battery performance degraded significantly. For example, for the anode sheets with 10-20 atomic layers, only a reversible capacity of 389 mAh g-1 could be obtained after 100 cycles at 0.1 A g-1. Density functional theory calculations coupled with experimental results were used to elucidate the sodiation mechanism of the SnO nanosheets. This systematic study of monolayer-dependent physical and electrochemical properties of 2D anodes shows a promising pathway to engineering and mitigating volume changes in 2D anode materials for sodium ion batteries. It also demonstrates that ultrathin SnO nanosheets are promising SIB anode materials with high specific capacity, stable cyclability, and excellent rate performance.

  14. Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun J.; Oh, Sang Youp; Kim, Ho Y.; Yoon, Sam S. [Dept. of Mechanical, Korea University Anamdong, 5-Ga, Sungbukgu, 136-713 Seoul (Korea); James, Scott C. [Thermal/Fluid Science and Engineering, Sandia National Labs, PO Box 969, Livermore, CA 94551 (United States)

    2010-11-15

    Because of thermal fluid-property dependence, atomization stability (or flow regime) can change even at fixed operating conditions when subject to temperature change. Particularly at low temperatures, fuel's high viscosity can prevent a pressure-swirl (or simplex) atomizer from sustaining a centrifugal-driven air core within the fuel injector. During disruption of the air core inside an injector, spray characteristics outside the nozzle reflect a highly unstable, nonlinear mode where air core length, Sauter mean diameter (SMD), cone angle, and discharge coefficient variability. To better understand injector performance, these characteristics of the pressure-swirl atomizer were experimentally investigated and data were correlated to Reynolds numbers (Re). Using a transparent acrylic nozzle, the air core length, SMD, cone angle, and discharge coefficient are observed as a function of Re. The critical Reynolds numbers that distinguish the transition from unstable mode to transitional mode and eventually to a stable mode are reported. The working fluids are diesel and a kerosene-based fuel, referred to as bunker-A. (author)

  15. Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model

    Science.gov (United States)

    Paziresh, M.; Kingston, A. M.; Latham, S. J.; Fullagar, W. K.; Myers, G. M.

    2016-06-01

    Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073-2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127-135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260-1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (ρ) and

  16. CrossRef Large numbers of cold positronium atoms created in laser-selected Rydberg states using resonant charge exchange

    CERN Document Server

    McConnell, R; Kolthammer, WS; Richerme, P; Müllers, A; Walz, J; Grzonka, D; Zielinski, M; Fitzakerley, D; George, MC; Hessels, EA; Storry, CH; Weel, M

    2016-01-01

    Lasers are used to control the production of highly excited positronium atoms (Ps*). The laser light excites Cs atoms to Rydberg states that have a large cross section for resonant charge-exchange collisions with cold trapped positrons. For each trial with 30 million trapped positrons, more than 700 000 of the created Ps* have trajectories near the axis of the apparatus, and are detected using Stark ionization. This number of Ps* is 500 times higher than realized in an earlier proof-of-principle demonstration (2004 Phys. Lett. B 597 257). A second charge exchange of these near-axis Ps* with trapped antiprotons could be used to produce cold antihydrogen, and this antihydrogen production is expected to be increased by a similar factor.

  17. A Study on Hybrid Absorbing Material with Multilayer Metallic Wire Grids%多层金属栅网混合结构吸波特性分析

    Institute of Scientific and Technical Information of China (English)

    韩彦明; 唐守柱; 何丙发

    2013-01-01

    文中采用传输矩阵理论和二端口级联网络分析了多层金属栅网混合结构的吸波特性,通过将多层金属栅网与多层介质阻抗匹配,在介质厚度不变的情况下,明显提高了混合结构的吸收峰值;同时,通过调整每层金属栅网的半径、间距,可调整混合结构吸收峰值位置,给出了典型混合结构的仿真计算结果.结果表明,混合结构吸收峰值可提高6 dB以上,在保证吸收效果的前提下,调整了吸收峰值的位置,可根据要求用于设计不同频段的吸波材料.%Absorbing properties of hybrid material with multilayer metallic wire grids is studied in this paper, with the transfer matrix method and two ports transmission formula of microwave simulation technology. Utilizing the impedance matching between multilayer metallic wire grids and multilayer absorbing material , we can improve maximum absorbing of the hybrid absorbing material, under the thichness of the multilayer absorbing material is invariant. And we can adjust the location of maximum absorbing with adjusting the radious and space of multilayer metallic wire grids. Some typical optimization simulation results are given. The results show that the designed maximum absorbing of the hybrid absorbing material with multilayer metallic wire grids can improve over 6 dB,And adjusted the location of maximum absorbing under keeping the good absorbing properties of hybrid material. The techniques can design different frequency absorbing material with design requirements.

  18. Atomic Number Dependence of Hadron Production at Large Transverse Momentum in 300 GeV Proton--Nucleus Collisions

    Science.gov (United States)

    Cronin, J. W.; Frisch, H. J.; Shochet, M. J.; Boymond, J. P.; Mermod, R.; Piroue, P. A.; Sumner, R. L.

    1974-07-15

    In an experiment at the Fermi National Accelerator Laboratory we have compared the production of large transverse momentum hadrons from targets of W, Ti, and Be bombarded by 300 GeV protons. The hadron yields were measured at 90 degrees in the proton-nucleon c.m. system with a magnetic spectrometer equipped with 2 Cerenkov counters and a hadron calorimeter. The production cross-sections have a dependence on the atomic number A that grows with P{sub 1}, eventually leveling off proportional to A{sup 1.1}.

  19. Study of mass attenuation coefficients and effective atomic numbers of bismuth-ground granulated blast furnace slag concretes

    Science.gov (United States)

    Kumar, Sandeep; Singh, Sukhpal

    2016-05-01

    Five samples of Bismuth-Ground granulated blast furnace slag (Bi-GGBFS) concretes were prepared using composition (0.6 cement + x Bi2O3 + (0.4-x) GGBFS, x = 0.05, 0.10, 0.15, 0.20 and 0.25) by keeping constant water (W) cement (C) ratio. Mass attenuation coefficients (μm) of these prepared samples were calculated using a computer program winXCOM at different gamma ray energies, whereas effective atomic numbers (Zeff) is calculated using mathematical formulas. The radiation shielding properties of Bi-GGBFS concrete has been compared with standard radiation shielding concretes.

  20. Prediction of microwave absorption properties of tetrapod-needle zinc oxide whisker radar absorbing material without prior knowledge

    Science.gov (United States)

    Zhao, Yu-Chen; Wang, Jie; Liu, Jiang-Fan; Song, Zhong-Guo; Xi, Xiao-Li

    2017-07-01

    The radar absorbing material (RAM) containing a tetrapod-needle zinc oxide whisker (T-ZnOw) has been proved to have good efficiency of microwave absorption. However, the available theoretical models, which are intended to predict the microwave absorbing properties of such an interesting composite, still cannot work well without some prior knowledge, like the measured effective electromagnetic parameters of the prepared T-ZnOw composite. Hence, we propose a novel predictive method here to calculate the reflectivity of T-ZnOw RAM without prior knowledge. In this method, the absorbing ability of this kind of material is divided into three main aspects: the unstructured background, the conductive network, and the nanostructured particle. Then, the attenuation properties of these three parts are represented, respectively, by three different approaches: the equivalent spherical particle and the static strong fluctuation theory, the equivalent circuit model obtained from the complex impedance spectra technology, and the combination of four different microscopic electromagnetic responses. The operational calculation scheme can be obtained by integrating these three absorption effects into the existing theoretical attenuation model. The reasonable agreement between the theoretical and experimental data of a T-ZnON/SiO2 composite in the range of 8-14 GHz shows that the proposed scheme can predict the microwave absorption properties of the T-ZnOw RAM. Furthermore, a detailed analysis of these three mechanisms indicates that, on the one hand, the background plays a dominant role in determining the real part of the effective permittivity of the T-ZnOw composite while the network and the particle are the decisive factors of its material loss; on the other hand, an zero-phase impedance, i.e., a pure resistance, with appropriate resonance characteristic might be a rational physical description of the attenuation property of the conductive network, but it is difficult to realize

  1. On the effective atomic number and electron density: A comprehensive set of formulas for all types of materials and energies above 1 keV

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Thind, K.S.;

    2008-01-01

    A comprehensive and consistent set of formulas is given for calculating the effective atomic number and electron density for all types of materials and for all photon energies greater than 1 keV. The are derived from first principles using photon interaction cross sections of the constituent atoms...

  2. Research Progress on Structural Design of Polymer Matrix Microwave Absorbing Materials%聚合物基吸波材料结构设计研究进展

    Institute of Scientific and Technical Information of China (English)

    段磊; 温变英

    2014-01-01

    The distribution characteristics and types of present absorbents in polymer matrix were introduced. Comparing with the structure of single layer polymer matrix microwave absorbing materials,the design principle of pyramidal, double layer and multi layer of polymer matrix microwave absorbing materials was emphasized. The structure feature and research progress on pyramidal and layer structure of polymer matrix microwave absorbing materials were reviewed, and future development trends was also presented.%介绍了目前吸收剂在聚合物基体中的分布特点和类型,通过与单层聚合物基吸波材料的结构对比,重点阐述了聚合物基吸波材料角锥、双层、多层结构的设计原理。同时对聚合物基吸波材料的角锥和层状结构特征与研究进展进行了综述,并对其发展方向提出了展望。

  3. High fidelity simulation and analysis of liquid jet atomization in a gaseous crossflow at intermediate Weber numbers

    Science.gov (United States)

    Li, Xiaoyi; Soteriou, Marios C.

    2016-08-01

    Recent advances in numerical methods coupled with the substantial enhancements in computing power and the advent of high performance computing have presented first principle, high fidelity simulation as a viable tool in the prediction and analysis of spray atomization processes. The credibility and potential impact of such simulations, however, has been hampered by the relative absence of detailed validation against experimental evidence. The numerical stability and accuracy challenges arising from the need to simulate the high liquid-gas density ratio across the sharp interfaces encountered in these flows are key reasons for this. In this work we challenge this status quo by presenting a numerical model able to deal with these challenges, employing it in simulations of liquid jet in crossflow atomization and performing extensive validation of its results against a carefully executed experiment with detailed measurements in the atomization region. We then proceed to the detailed analysis of the flow physics. The computational model employs the coupled level set and volume of fluid approach to directly capture the spatiotemporal evolution of the liquid-gas interface and the sharp-interface ghost fluid method to stably handle high liquid-air density ratio. Adaptive mesh refinement and Lagrangian droplet models are shown to be viable options for computational cost reduction. Moreover, high performance computing is leveraged to manage the computational cost. The experiment selected for validation eliminates the impact of inlet liquid and gas turbulence and focuses on the impact of the crossflow aerodynamic forces on the atomization physics. Validation is demonstrated by comparing column surface wavelengths, deformation, breakup locations, column trajectories and droplet sizes, velocities, and mass rates for a range of intermediate Weber numbers. Analysis of the physics is performed in terms of the instability and breakup characteristics and the features of downstream

  4. Formation and decay of fluorobenzene radical anions affected by their isomeric structures and the number of fluorine atoms.

    Science.gov (United States)

    Higashino, Saki; Saeki, Akinori; Okamoto, Kazumasa; Tagawa, Seiichi; Kozawa, Takahiro

    2010-08-12

    Aryl fluoride has attracted much attention as a resist component for extreme ultraviolet (EUV) lithography, because of the high absorption cross section of fluorine for EUV photons; however, less is known about electron attachment to fluorobenzene (FBz) and the stability of the reduced state. Picosecond and nanosecond pulse radiolysis of tetrahydrofuran solutions of FBz from mono-, di-, tri-, tetra-, penta-, and hexafluorobenzene was performed, and the effects of isomeric structure and number of fluorine atoms were examined. Scavenging of solvated electrons was found to correlate with the electron affinity obtained by density functional theory in the gas phase, whereas the decay of FBz radical anions was dominated by the activation energy of fluorine anion dissociation calculated using a polarized continuum model (PCM). A sharp contrast in the lifetimes of ortho-, meta-, and para-position difluorobenzene was observed, which could provide information on the molecular design of functional materials.

  5. Entanglement swapping and teleportation based on cavity QED method using the nonlinear atom-field interaction: Cavities with a hybrid of coherent and number states

    Science.gov (United States)

    Pakniat, R.; Tavassoly, M. K.; Zandi, M. H.

    2017-01-01

    In this paper, we outline a scheme for entanglement swapping based on the concept of cavity QED. The atom-field entangled state in our study is produced in the nonlinear regime. In this scheme, the exploited cavities are prepared in a hybrid entangled state (a combination of coherent and number states) and the swapping process is investigated using two different methods, i.e., detecting and Bell-state measurement methods through the cavity QED. Then, we make use of the atom-field entangled state obtained by detecting method to show that how the atom-atom entanglement as well as atomic and field states teleportation can be achieved with complete fidelity.

  6. 纤维素基高吸水材料研究进展%Research progress in cellulose-based super absorbent material

    Institute of Scientific and Technical Information of China (English)

    马东卓; 祝宝东; 王鉴; 张帅; 潘宇亭; 何乾坤

    2014-01-01

    Super absorbent material is a new type of functional polymer material with important application value. This article reviews the pretreatment,the graft modification and the compound modification of natural cellulose in recent years,and also introduces fungi cellulose. Pretreatment methods are emphasized,including alkalization,etherification,ionic liquids dispose and organic solvent dispose,the graft modification of cellulose and cellulose derivatives,and the preparation of super absorbent material by cellulose/silicate complex,cellulose/metal nanoparticles complex and cellulose/highpolymer complex. The cellulose-based super absorbent materials have a wide applied perspective in agriculture,pharmacy and environmental protection.%纤维素基高吸水材料是一种新型的功能高分子材料,具有重要的应用价值。本文综述了近年来天然纤维素的预处理、接枝改性和复合改性,并介绍了菌类纤维素,主要阐述了碱化、醚化、离子液体和有机溶剂对纤维素的预处理,纤维素、纤维素衍生物接枝改性以及纤维素与硅酸盐矿物,金属纳米粒子和高聚物复合制备高吸水材料,指出纤维素基高吸水材料在农业、制药、环保等领域应用前景广阔。

  7. Research Progress in Cellulose-based Absorbent Material%纤维素系吸水材料的研究现状及发展前景

    Institute of Scientific and Technical Information of China (English)

    高桂林; 沈葵忠; 房桂干; 邓拥军; 李萍; 金莉; 别士霞

    2012-01-01

    This review addressed recent progress in cellulose-based absorbent materials preparation and application Firstly, absorbent material produced directly from native cellulose (including bacterial cellulose) via cellulose dissolution are introduced. Secondly, cellulose highly absorbing polymer based on its derivatives which were obtained by physical as well as chemical cross-linking strategies was discussed. Thirdly, composite prepared by using cellulose in conjunction with other polymers through blending, formation of polyelectrolyte complexes, and interpenetrating polymer networks (IPNs) technology was addressed . Finally, cellulose-inorganic hybrid hydrogel prepared by embedding inorganic nano-partieles in cellulose matrices was described. In addition,the prospect of cellulosic absorbent materials and some problems still needed to be solved were summarized.%本文回顾了近年来纤维素系吸水材料的制备方法及其应用,具体介绍了纤维素系吸水材料的几种主要制备方法:一是直接对天然纤维素进行处理来制备;第二是利用纤维素衍生物通过物理或化学交联的方法制备;第三是将纤维素与其他聚合物进行反应形成复合树脂或聚电解质配合物,还可以采用互穿聚合网络技术进行处理;另外将无机纳米粒子嵌入纤维素矩阵中也可以制备纤维素-无机混合凝胶树脂。最后还对纤维素系高吸水材料的发展前景以及仍需解决的问题进行了总结。

  8. Effective atomic numbers, electron densities, and tissue equivalence of some gases and mixtures for dosimetry of radiation detectors

    Directory of Open Access Journals (Sweden)

    Singh Vishwanath P.

    2012-01-01

    Full Text Available Total mass attenuation coefficients, µm, effective atomic number, Zeff, and effective electron density, Neff, of different gases - carbon dioxide, methane, acetylene, propane, butane, and pentane used in radiation detectors, have been calculated for the photon energy of 1 keV to 100 GeV. Each gas has constant Zeff values between 0.10 to 10 MeV photon energies; however, these values are way far away from ICRU tissue. Carbon dioxide gas shows the closest tissue equivalence in the entire photon energy spectrum. Relative tissue equivalences of the mixtures of gases with respect to ICRU tissue are in the range of 0.998-1.041 for air, argon (4.5% + methane (95.5%, argon (0.5% + carbon dioxide (99.5%, and nitrogen (5% + methane (7% + carbon dioxide (88%. The gas composition of xenon (0.5% + carbon dioxide (99.5% shows 1.605 times higher tissue equivalence compared to the ICRU tissue. The investigated photon interaction parameters are useful for exposure and energy absorption buildup factors calculation and design, and fabrication of gaseous detectors for ambient radiation measurement by the Geiger-Muller detector, ionization chambers and proportional counters.

  9. Influence of the effective atomic number in the thermoluminescent response; Influencia del numero atomico efectivo en la respuesta termoluminiscente

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P.R. [ININ, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2006-07-01

    Nowadays the thermoluminescent dosimetry is one of the methods more reliable for ionizing radiation dosimetry, for that in many parts of the world, different research groups continue in the development of new TL materials. Notwithstanding, the use of these materials for dosimetric radiation purposes, should to take into account the effective atomic number (Z{sub eff}) to avoid an underestimate or overestimation of the measured dose, for example, in radiodiagnostic or radiotherapy. It is well known that some materials considered as equivalent to the soft biological tissue, present smaller sensitivity when being irradiated with low energy photons, while the TL material considered as not equivalent to the tissue, presents the supra sensitivity effect. In this work the results of the TL signal shown by different TL materials, when being irradiated with photons of effective energy between 24 keV and 1.25 MeV, and its relationship with their Z{sub eff} calculated by three methods are presented. (Author)

  10. Determination of total mass attenuation coefficients, effective atomic numbers and electron densities for different shielding materials used in radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Almeida J, A. T. [FUNDACENTRO, Centro Regional de Minas Gerais, Brazilian Institute for Safety and Health at Work, Belo Horizonte, 30180-100 Minas Gerais (Brazil); Nogueira, M. S. [Center of Development of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Santos, M. A. P., E-mail: mnogue@cdtn.br [Regional Center for Nuclear Science / CNEN, 50.740-540 Recife, Pernambuco (Brazil)

    2015-10-15

    Full text: In this paper, the interaction of X-rays with some shielding materials has been studied for materials containing different amounts of barite and aggregates. The total mass attenuation coefficient (μ{sub t}) for three shielding materials has been calculated by using WinXCOM program in the energy range from RQR qualities (RQR-4, RQR-6, RQR-9, and RQR-10). They were: cream barite (density 2.99 g/cm{sup 3} collected in the State of Sao Paulo), purple barite (density 2.95 g/cm{sup 3} collected in the State of Bahia) and white barite (density 3.10 g/cm{sup 3} collected in the State of Paraiba). The chemical analysis was carried out by an X-ray fluorescence spectrometer model EDX-720, through dispersive energy. The six elements of the higher concentration found in the sample and analyzed by Spectrophotometry of Energy Dispersive X-ray for the samples were Ba(60.9% - white barite), Ca(17,92% - cream barite), Ce(3,60% - white barite), Fe(17,16% - purple barite), S(12,11% - white barite) and Si(29,61% - purple barite). Also, the effective atomic number (Z{sub eff}) and the effective electron density (N{sub eff}) were calculated using the values of the total mass attenuation coefficient. The dependence of these parameters on the incident photon energy and the chemical composition has been examined. (Author)

  11. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK’s Initial Operational Response (IOR)

    Science.gov (United States)

    Kassouf, Nick; Syed, Sara; Larner, Joanne; Amlôt, Richard

    2017-01-01

    The UK’s Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method (“rinse-wipe-rinse”) for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants. PMID:28152053

  12. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK's Initial Operational Response (IOR).

    Science.gov (United States)

    Kassouf, Nick; Syed, Sara; Larner, Joanne; Amlôt, Richard; Chilcott, Robert P

    2017-01-01

    The UK's Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method ("rinse-wipe-rinse") for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants.

  13. X-ray emission from a high-atomic-number z-pinch plasma created from compact wire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, T.W.L.; Nash, T.J.; Marder, B.M. [and others

    1996-03-01

    Thermal and nonthermal x-ray emission from the implosion of compact tungsten wire arrays, driven by 5 MA from the Saturn accelerator, are measured and compared with LLNL Radiation-Hydro-Code (RHC) and SNL Hydro-Code (HC) numerical models. Multiple implosions, due to sequential compressions and expansions of the plasma, are inferred from the measured multiple x-radiation bursts. Timing of the multiple implosions and the thermal x-ray spectra measured between 1 and 10 keV are consistent with the RHC simulations. The magnitude of the nonthermal x-ray emission measured from 10 to 100 keV ranges from 0.02 to 0.08% of the total energy radiated and is correlated with bright-spot emission along the z-axis, as observed in earlier Gamble-11 single exploding-wire experiments. The similarities of the measured nonthermal spectrum and bright-spot emission with those measured at 0.8 MA on Gamble-II suggest a common production mechanism for this process. A model of electron acceleration across magnetic fields in highly-collisional, high-atomic-number plasmas is developed, which shows the existence of a critical electric field, E{sub c}, below which strong nonthermal electron creation (and the associated nonthermal x rays) do not occur. HC simulations show that significant nonthermal electrons are not expected in this experiment (as observed) because the calculated electric fields are at least one to two orders-of-magnitude below E{sub c}. These negative nonthermal results are confirmed by RHC simulations using a nonthermal model based on a Fokker-Plank analysis. Lastly, the lower production efficiency and the larger, more irregular pinch spots formed in this experiment relative to those measured on Gamble II suggest that implosion geometries are not as efficient as single exploding-wire geometries for warm x-ray production.

  14. Study of effective atomic numbers and electron densities, kerma of alcohols, phantom and human organs, and tissues substitutes

    Directory of Open Access Journals (Sweden)

    Singh Vishwanath P.

    2013-01-01

    Full Text Available Effective atomic numbers (ZPIeff and electron densities of eighteen alcohols such as wood alcohol, CH3OH; grain alcohol, C2H5OH; rubbing alcohol, C3H7OH; butanol, C4H9OH; amyl alcohol, C5H11OH; cetyl alcohol, C16H33OH; ethylene glycol, C2H4(OH2; glycerin, C3H5(OH3; PVA, C2H4O; erythritol, C4H6(OH4; xylitol, C5H7(OH5; sorbitol, C6H8(OH6; volemitol, C7H9(OH7; allyl alcohol, C3H5OH; geraniol, C10H17OH; propargyl alcohol, C3H3OH; inositol, C6H6(OH6, and menthol, C10H19OH have been calculated in the photon energy region of 1 keV-100 GeV. The estimated values have been compared with experimental values wherever possible. The comparison of ZPIeff of the alcohols with water phantom and PMMA phantom indicate that the ethylene glycol, glycerin, and PVA are substitute for PMMA phantom and PVA is substitute of water phantom. ZPIeff of alcohols have also been compared with human organs and tissues. Ethylene glycol, glycerin and PVA, allyl alcohol, and wood alcohols are found tissue substitutes for most of human organs. Kerma which is the product of the energy fluence and mass energy-absorption coefficient, have been calculated in the energy region from 1 keV to 20 MeV for the alcohols. The results show the kerma is more or less independent of energy above 100 keV.

  15. Synthesis and characterisation of Copper Zinc Tin Sulphide (CZTS) compound for absorber material in solar-cells

    Science.gov (United States)

    Kheraj, Vipul; Patel, K. K.; Patel, S. J.; Shah, D. V.

    2013-01-01

    The development of thin-film semiconductor compounds, such as Copper Indium Gallium Selenide (CIGS), has caused remarkable progress in the field of thin-film photovoltaics. However, the scarcity and the increasing prices of indium impose the hunt for alternative materials. The Copper Zinc Tin Sulphide (CZTS) is one of the promising emerging materials with Kesterite-type crystal structure and favourable material properties like high absorption co-efficient and direct band-gap. Moreover, all the constituent elements of CZTS are non-toxic and aplenty on the earth-crust, making it a potential candidate for the thin-film photovoltaics. Here we report the synthesis of CZTS powder from its constituent elements, viz. copper, zinc, tin and sulphur, in an evacuated Quartz ampoule at 1030 K temperature. The sulphur content in the raw mixture in the ampoule was varied and optimised in order to attain the desired atomic stoichiometry of the compound. The synthesised powder was characterised by X-Ray diffraction technique (XRD), Raman Scattering Spectroscopy, Energy Dispersive Analysis of X-Ray (EDAX) and UV-Visible Absorption Spectra. The XRD Patterns of the synthesised compound show the preferred orientation of (112), (220) and (312) planes, confirming the Kesterite structure of CZTS. The chemical composition of the powder was analysed by EDAX and shows good atomic stoichiometry of the constituent elements in the CZTS compound. The UV-Vis absorption spectra confirm the direct band-gap of about 1.45 eV, which is quite close to the optimum value for the semiconductor material as an absorber in solar-cells.

  16. Development of a standard data base for FBR core nuclear design. 10. Reevaluation of atomic number density of JOYO Mk-II core

    Energy Technology Data Exchange (ETDEWEB)

    Numata, Kazuyuki; Sato, Wakaei [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Ishikawa, Makoto; Arii, Yoshio [Nuclear Energy System Incorporation, Tokyo (Japan)

    1999-07-01

    The material composition of JOYO Mk-II core components in its initial core was reevaluated as a part of the effort for developing a standard data base for FBR core nuclear design. The special feature of the reevaluation is to treat the decay of Pu-241 isotope, so that the atomic number densities of Pu-241 and Am-241 in fuel assemblies can be exactly evaluated on the initial critical date, Nov. 22nd, 1982. Further, the atomic number densities of other core components were also evaluated to improve the analytical accuracy. Those include the control rods which were not so strictly evaluated in the past, and the dummy fuels and the neutron sources which were not treated in the analytical model so far. The results of the present reevaluation were as follows: (1) The changes of atomic number densities of the major nuclides such as Pu-239, U-235 and U-238 were about {+-}0.2 to 0.3%. On the other hand, the number density of Pu-241, which was the motivation of the present work, was reduced by 12%. From the fact, the number densities in the past analysis might be based on the isotope measurement of the manufacturing point of time without considering the decay of Pu-241. (2) As the other core components, the number densities of control rods and outer reflector-type A were largely improved. (author)

  17. Development of a standard data base for FBR core nuclear design. 10. Reevaluation of atomic number density of JOYO Mk-II core

    Energy Technology Data Exchange (ETDEWEB)

    Numata, Kazuyuki; Sato, Wakaei [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Ishikawa, Makoto; Arii, Yoshio [Nuclear Energy System Incorporation, Tokyo (Japan)

    1999-07-01

    The material composition of JOYO Mk-II core components in its initial core was reevaluated as a part of the effort for developing a standard data base for FBR core nuclear design. The special feature of the reevaluation is to treat the decay of Pu-241 isotope, so that the atomic number densities of Pu-241 and Am-241 in fuel assemblies can be exactly evaluated on the initial critical date, Nov. 22nd, 1982. Further, the atomic number densities of other core components were also evaluated to improve the analytical accuracy. Those include the control rods which were not so strictly evaluated in the past, and the dummy fuels and the neutron sources which were not treated in the analytical model so far. The results of the present reevaluation were as follows: (1) The changes of atomic number densities of the major nuclides such as Pu-239, U-235 and U-238 were about {+-}0.2 to 0.3%. On the other hand, the number density of Pu-241, which was the motivation of the present work, was reduced by 12%. From the fact, the number densities in the past analysis might be based on the isotope measurement of the manufacturing point of time without considering the decay of Pu-241. (2) As the other core components, the number densities of control rods and outer reflector-type A were largely improved. (author)

  18. Tuning optical properties of magic number cluster (SiO2)4O2H4 by substitutional bonding with gold atoms.

    Science.gov (United States)

    Cai, Xiulong; Zhang, Peng; Ma, Liuxue; Zhang, Wenxian; Ning, Xijing; Zhao, Li; Zhuang, Jun

    2009-04-30

    By bonding gold atoms to the magic number cluster (SiO(2))(4)O(2)H(4), two groups of Au-adsorbed shell-like clusters Au(n)(SiO(2))(4)O(2)H(4-n) (n = 1-4) and Au(n)(SiO(2))(4)O(2) (n = 5-8) were obtained, and their spectral properties were studied. The ground-state structures of these clusters were optimized by density functional theory, and the results show that in despite of the different numbers and types of the adsorbed Au atoms, the cluster core (SiO(2))(4)O(2) of T(d) point-group symmetry keeps almost unchanged. The absorption spectra were obtained by time-dependent density functional theory. From one group to the other, an extension of absorption wavelength from the UV-visible to the NIR region was observed, and in each group the absorption strengths vary linearly with the number of Au atoms. These features indicate their advantages for exploring novel materials with easily controlled tunable optical properties. Furthermore, due to the weak electronic charge transfer between the Au atoms, the clusters containing Au(2) dimers, especially Au(8)(SiO(2))(4)O(2), absorb strongly NIR light at 900 approximately 1200 nm. Such strong absorption suggests potential applications of these shell-like clusters in tumor cells thermal therapy, like the gold-coated silica nanoshells with larger sizes.

  19. Effects of Adding of Two Commercial Absorbent Materials and Natural Zeolite to the Diets Contaminated with Aflatoxin B1 on Broiler Performance and their

    Directory of Open Access Journals (Sweden)

    J. Azimi

    2013-03-01

    Full Text Available This study was conducted to evaluate the effect of adding of two commercial absorbent products in feeds and to compare the results with the effect of adding of natural zeolite in reducing the adverse effects of aflatoxin B1 on broiler growth, performance and immune system. In this study, 200 one day old Arian 386 broiler chickens were used in a completely randomized design with 5 treatments, 4 replications and 10 chicks per each treatment. Experimental groups were as follows: negative control fed basal diet; positive control fed basal diet plus 1 mg aflatoxin B1 kg-1 diet; and three other groups fed 25g/kg Milbond-TX, Polysorb and Zeolite with 1 mg/kg aflatoxin B1, respectively. Feed intake did not significantly differ between the groups. The body weight gain and feed conversion ratio of birds fed contaminated diets were significantly decreased and increased, respectively but adding of the absorbent materials to contaminated feed caused a significant improvement in body weight gain and feed conversion. Among the internal organs, the spleen relative weights increased by consumption of aflatoxin B1contaminated feed. Aflatoxin B1 use without absorbent materials significantly decreased antibody production against Newcastle disease vaccine in 21 day. In addition, produced antibodies against sheep red blood cells in 35 day of age in birds fed aflatoxin B1 contaminated diets were reduced. The results of this study showed that the adding of natural zeolite and commercial absorbents in feeds contaminated with aflatoxin B1 causes improved performance and immune system compared with the group that received the aflatoxin B1 alone.

  20. 多层微波吸收材料的遗传算法设计%Design of multilayer microwave absorbing material based on Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    张丹枫; 张敏; 曾国勋; 吴子秋

    2013-01-01

    利用遗传算法(GA)编写多涂层优化设计程序,该程序可以调用矢量网络分析仪测量的电磁参数,根据吸波材料的电磁参数对0.5~6.0 GHz范围内不同材料的涂层厚度进行优化设计;讨论了不同的目标函数和厚度优化方法对优化结果的影响,提出多常数权重法建立目标函数.结果表明:此方法可以简单地从材料电磁参数的数据库中,按照设定的要求计算得到最优的电磁波吸收涂层;利用提出的多常数权重法建立的目标函数可以更好的设计宽频带高吸收的电磁波吸收涂层.%An optimum designing program of multilayer absorbing material is compiled based on Genetic Algorithm (GA). The program transfers the electromagnetic parameters which measured by vector network analyzer, and can process thickness optimum design of different absorbing materials in the range of 0.5-6.0 GHz. The results show that the best absorbing layers can be easily gained from the electromagnetic parameter database by computing with this program according to the requirement. The multi-constant weight method is very helpful to design the microwave absorbing layers of broad-frequency and high absorption.

  1. The Investigation on the Potential of Coconut Shell Powder Composite in Term of Carbon Composition, Surface Porosity and Dielectric Properties as a Microwave Absorbing Material

    Directory of Open Access Journals (Sweden)

    Yew Been Seok

    2016-01-01

    Full Text Available Agricultural wastes are renewable resources that are potentially useful as microwave absorbing materials. This paper presents the investigation on the carbon composition, surface porosity of the raw coconut shell powder particles and the dielectric properties of coconut shell powder with epoxy resin matrix composites. From CHNS elemental analysis, it was found that the carbon composition of coconut shell powder is 46.700%. Presences of macropores (≈ 2μm were detected in the SEM analysis of the coconut shell powder particles. Measurement on dielectric properties of the coconut shell powder composites was performed by using open-ended coaxial probe method over microwave frequency range of 1-8 GHz. The overall dielectric constant (εr’ and dielectric loss factor (εr” of the composite with ratio 50:50 were 3.56 and 0.26, ranging from 3.35-3.76 and 0.21-0.30 respectively; whereas for composite ratio 40:60, the overall dielectric constant (εr’ and dielectric loss factor (εr” were 2.97 and 0.21, ranging from 2.74-3.17 and 0.16-0.27 respectively. The electrical conductivity calculated based on measured εr” was 0.067 and 0.054 for composite ratio 50:50 and 40:60 respectively. The dielectric properties and electrical conductivity of the coconut shell powder composites were influenced by the greater presence of high dielectric material (coconut shell powder. This experimental investigation on the potential of the coconut shell powder with epoxy resin composites indicates that the ability of the composite to absorb and convert microwave signals is dependent on the carbonaceous materials of the composite. This result offers a great opportunity to diversify the use of coconut shell powder as microwave absorbing material.

  2. Fidelity of quantum information for Ⅴ-type three-level atom interacting with a number state light field in Kerr medium

    Institute of Scientific and Technical Information of China (English)

    Liu Su-Mei; He An-Zhi; Ji Yun-Jing

    2008-01-01

    In this paper the evolution characteristics of the fidelity of quantum information for the Ⅴ-type three-level atom interacting with number state light field in Kerr medium are investigated. It shows that the periodicity of the evolutions of fidelity of quantum information is influenced by the Kerr coefficient, the photon number of the initial field and intensity of light. The evolutions of the fidelity of quantum information are modulated by the initial number state field. The Rabi oscillation frequency and the modulation frequency of fidelity for the field and the system vary with the value of the Kerr coefficient. The evolutions of fidelity of quantum information obviously show the quantum collapse and revival behaviours in the system of atom interacting with light field.

  3. Progress in high-energy ball milling for the preparation of absorbing materials%吸波材料的高能球磨工艺研究进展

    Institute of Scientific and Technical Information of China (English)

    王锰刚; 谌静; 谢国治; 陈文俊; 李艳; 张泽敖; 王嘉波; 沈杨; 孙康; 周倜

    2016-01-01

    High-energy ball milling method has become a important way to prepare various absorbing materials, because of simple control, environmental production, low cost and high efficiency. This paper summarizes the recent research progress of high-energy ball milling process in absorbing materials,indicating that high-energy ball milling process in absorbing materials, especially in flaky absorbing materials with shape anisotropy, which has very broad application prospects. Then we look forward to the development prospects of high-energy ball milling process in absorbing materials.%高能球磨法由于其便于控制、生产环保、成本低、效率高等优点成为制备吸波材料的一种重要方法。总结了近期高能球磨工艺在吸波材料领域的应用研究进展,表明高能球磨工艺在吸波领域,尤其是在制备具有形状各向异性的片状吸波材料领域,具有十分广阔的应用前景,展望了高能球磨工艺在未来吸波材料领域的发展前景。

  4. Study of double bond equivalents and the numbers of carbon and oxygen atom distribution of dissolved organic matter with negative-mode FT-ICR MS.

    Science.gov (United States)

    Bae, EunJung; Yeo, In Joon; Jeong, Byungkwan; Shin, Yongsik; Shin, Kyung-Hoon; Kim, Sunghwan

    2011-06-01

    A strong linear relationship was observed between the average double bond equivalence (DBE) and the ratio of carbon to oxygen atoms in oxygenated compounds of dissolved organic matter (DOM). Data were acquired by a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS), equipped with a negative-mode electrospray ionization source. The slope and y-intercepts extracted from the linear relationship can be used to compare DOM samples originating from different locations. Significant differences in these parameters were observed between inland riverine and offshore coastal DOM samples. Offshore coastal DOM molecules underwent a change of one DBE for each removal or addition of two oxygen atoms. This suggested the existence of multiple carboxyl groups, each of which contains a double bond and two oxygen atoms. Inland riverine samples exhibited a change of ~1.5 DBE following the addition or removal of two oxygen atoms. This extra change in DBE was attributed to cyclic structures or unsaturated chemical bonds. The DBE value with maximum relative abundance and the minimum DBE value for each class of oxygenated compounds showed that approximately two oxygen atoms contributed to a unity change in DBE. The qualitative analyses given here are in a good agreement with results obtained from analyses using orthogonal analytical techniques. This study demonstrates that DBE and the carbon number distribution, observed by high resolution mass spectrometry, can be valuable in elucidating and comparing structural features of oxygenated molecules of DOM.

  5. Effective atomic number of some sugars and amino acids for scattering of (241)Am and (137)Cs gamma rays at low momentum transfer.

    Science.gov (United States)

    Vinaykumar, L; Umesh, T K

    2015-09-01

    In this paper, we report the effective atomic number of some H, C, N and O based sugars and amino acids. These have been determined by using a handy expression which is based on the theoretical angle integrated small angle (coherent+incoherent) scattering cross sections of seven elements of Z≤13 in four angular ranges of (0-4°), (0-6°), (0-8°) and (0-10°)for (241)Am (59.54 keV) and (137)Cs (661.6 keV) gamma rays. The theoretical scattering cross sections were computed by a suitable numerical integration of the atomic form factor and incoherent scattering function compilations of Hubbell et al. (1975) which make use of the non-relativistic Hartree-Fock (NRHF) model for the atomic charge distribution of the elements in the angular ranges of interest. The angle integrated small angle scattering cross sections of the H, C, N and O based sugars and amino acids measured by a new method reported recently by the authors were used in the handy expression to derive their effective atomic number. The results are compared with the other available data and discussed. Possible conclusions are drawn based on the present study. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. The Atomic orbitals of the topological atom

    OpenAIRE

    Ramos-Cordoba, Eloy; Salvador Sedano, Pedro

    2013-01-01

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These c...

  7. Effective atomic numbers of some H-, C-, N- and O-based composite materials derived from differential incoherent scattering cross-sections

    Indian Academy of Sciences (India)

    S Prasanna Kumar; V Manjunathaguru; T K Umesh

    2010-04-01

    In this work, we have made an effort to determine whether the effective atomic numbers of H-, C-, N- and O-based composite materials would indeed remain a constant over the energy grid of 280–1200 keV wherein incoherent scattering dominates their interaction with photons. For this purpose, the differential incoherent scattering cross-sections of Be, C, Mg, Al, Ca and Ti were measured for three scattering angles 60°, 80° and 100° at 279.1, 661.6 and 1115.5 keV using which an expression for the effective atomic number was derived. The differential incoherent scattering cross-sections of the composite materials of interest measured at these three angles in the same set-up and substituted in this expression would yield their effective atomic number at the three energies. Results obtained in this manner for bakelite, nylon, epoxy, teflon, perspex and some sugars, fatty acids as well as amino acids agreed to within 2% of some of the other available values. It was also observed that for each of these samples, eff was almost a constant at the three energies which unambiguously justified the conclusions drawn by other authors earlier [Manjunathaguru and Umesh, J. Phys. B: At. Mol. Opt. Phys. 39, 3969 (2006); Manohara et al, Nucl. Instrum. Methods B266, 3906 (2008); Manohara et al Phys. Med. Biol. 53, M377 (2008)] based on total interaction cross-sections in the energy grid of interest.

  8. Polarizabilities and van der Waals C6 coefficients of fullerenes from an atomistic electrodynamics model: Anomalous scaling with number of carbon atoms

    Science.gov (United States)

    Saidi, Wissam A.; Norman, Patrick

    2016-07-01

    The van der Waals C6 coefficients of fullerenes are shown to exhibit an anomalous dependence on the number of carbon atoms N such that C6 ∝ N2.2 as predicted using state-of-the-art quantum mechanical calculations based on fullerenes with small sizes, and N2.75 as predicted using a classical-metallic spherical-shell approximation of the fullerenes. We use an atomistic electrodynamics model where each carbon atom is described by a polarizable object to extend the quantum mechanical calculations to larger fullerenes. The parameters of this model are optimized to describe accurately the static and complex polarizabilities of the fullerenes by fitting against accurate ab initio calculations. This model shows that C6 ∝ N2.8, which is supportive of the classical-metallic spherical-shell approximation. Additionally, we show that the anomalous dependence of the polarizability on N is attributed to the electric charge term, while the dipole-dipole term scales almost linearly with the number of carbon atoms.

  9. Polarizabilities and van der Waals C6 coefficients of fullerenes from an atomistic electrodynamics model: Anomalous scaling with number of carbon atoms.

    Science.gov (United States)

    Saidi, Wissam A; Norman, Patrick

    2016-07-14

    The van der Waals C6 coefficients of fullerenes are shown to exhibit an anomalous dependence on the number of carbon atoms N such that C6 ∝ N(2.2) as predicted using state-of-the-art quantum mechanical calculations based on fullerenes with small sizes, and N(2.75) as predicted using a classical-metallic spherical-shell approximation of the fullerenes. We use an atomistic electrodynamics model where each carbon atom is described by a polarizable object to extend the quantum mechanical calculations to larger fullerenes. The parameters of this model are optimized to describe accurately the static and complex polarizabilities of the fullerenes by fitting against accurate ab initio calculations. This model shows that C6 ∝ N(2.8), which is supportive of the classical-metallic spherical-shell approximation. Additionally, we show that the anomalous dependence of the polarizability on N is attributed to the electric charge term, while the dipole-dipole term scales almost linearly with the number of carbon atoms.

  10. Modelling the effective atomic number and the packing factor of polyatomic compounds: Applications to refractive index and dosimetry

    Science.gov (United States)

    Lima, H.; Couto dos Santos, M. A.

    2016-09-01

    In this work, based on fundamental physics and chemistry (charge distribution, electronegativity, induced dipole moment), we are introducing an analytical expression for Zeff and a general way of calculating the crystal packing factor, p, of any ionic material. By using the average separation between the atomic and crystal(ionic) radii of the interacting ions, we are postulating an effective distance(Rij) between the positive and the negative centre of charge. When compared to the available experimental data, predictions within 20% have been obtained to Zeff of materials applied to dosimetry. In photonics, the increasing behaviour of the refractive index with Zeff is confirmed. By combining crystal field and effective charge models, we have predicted Zeff of the Eu2O3 within the range of available experimental data.

  11. 粘土/聚合物复合吸水材料的研究进展%Research Progress of Clay/Polymer Composite Absorbent Materials

    Institute of Scientific and Technical Information of China (English)

    朱林晖; 张丽丽; 丁马太; 杨静

    2011-01-01

    The influence of clay minerals on modification mechanism, modification methods of super-absorbent polymer was reviewed. The main types of current existed clay/polymer composite absorbent materials were introduced in the paper. The analysis showed that the main problem of the composite materials was very difficult to coordinate the relation among three factors, such as absorbent ability, gel strength and salt-resistance. The research direction in future is to compose it with natural resources to develop the eco-friendly products and apply them to remove high toxic dyes and harmful heavy metal ions from industrial wastewater.%综述了粘土矿物对于高吸水性聚合物的改性机理、改性方法的影响,介绍了目前粘土/聚合物复合吸水材料的主要种类。分析指出,吸水能力、凝胶强度与耐盐性三者乏阊难以统筹兼顾是这类复合材料当前存在的主要问题,将其与天然资源复合开发环境友好型产品,并用于废水中高毒染料和有害金属离子的去除是其今后的发展方向。

  12. 基于Smith圆图的吸波材料阻抗匹配设计%Impedance matching design of radar absorbing material based on Smith circle diagram

    Institute of Scientific and Technical Information of China (English)

    陈鑫; 刘祥萱

    2013-01-01

    采用Smith圆图对尖晶石镍铁氧体的输入阻抗进行表征,并根据传输线理论计算不同涂层厚度下尖晶石镍铁氧体的反射率。结果表明,Smith圆图中输入阻抗越接近点(α=1,β=0),阻抗匹配性越好,反射率也越小。这为基于Smith圆图的吸波材料阻抗匹配设计应用奠定了基础。%The input impedance of spinel nickel ferrite was characterized by Smith circle diagram,and the reflectivity of spinel nickel ferrite with different coating thicknesses was calculated by transmission line theory. The results show that the closer the input impedance in the Smith circle diagram is to the point(α=1,β=0),the better the impedance matching is,and the smaller the reflectance is,which lays the foundation for application of Smith circle diagram in impedance matching design of absorbing materials.

  13. Rotating Bose-Einstein condensates with a finite number of atoms confined in a ring potential: Spontaneous symmetry breaking beyond the mean-field approximation

    Science.gov (United States)

    Roussou, A.; Smyrnakis, J.; Magiropoulos, M.; Efremidis, Nikolaos K.; Kavoulakis, G. M.

    2017-03-01

    Motivated by recent experiments on Bose-Einstein condensed atoms which rotate in annular and/or toroidal traps, we study the effect of the finiteness of the atom number N on the states of lowest energy for a fixed expectation value of the angular momentum, under periodic boundary conditions. To attack this problem, we develop a general strategy, considering a linear superposition of the eigenstates of the many-body Hamiltonian, with amplitudes that we extract from the mean-field approximation. This many-body state breaks the symmetry of the Hamiltonian; it has the same energy to leading order in N as the mean-field state and the corresponding eigenstate of the Hamiltonian, however, it has a lower energy to subleading order in N and thus it is energetically favorable.

  14. Influence of the number of atomic levels on the spectral opacity of low temperature nickel and iron in the spectral range 50–300 eV

    Directory of Open Access Journals (Sweden)

    Busquet M.

    2013-11-01

    Full Text Available Opacity is a fundamental ingredient for the secular evolution of stars. The calculation of the stellar plasma absorption coefficients is complex due to the composition of these plasmas, generally an H /He dominated mixture with a low concentration of partially ionized heavy ions (the iron group. The international collaboration OPAC recently presented extensive comparisons of spectral opacities of iron and nickel for temperatures between 15 and 40 eV and for densities of ∼ 3 mg/cm3, relevant to the stellar envelope conditions [1, 2]. The role of Configuration Interaction (CI and the influence of the number of atomic levels on the opacity using the recently improved version of HULLAC atomic code [3, 4] are illustrated in this article. Comparisons with theoretical predictions already presented in [1] are discussed.

  15. Structural investigation and microwave characteristics of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Manaf, Azwar [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Indonesia of University (Indonesia); Adi, Wisnu Ari, E-mail: dwisnuaa@batan.go.id [Center for Technology of Nuclear Industry Material, National Nuclear Energy Agency (Indonesia)

    2014-03-24

    Synthesis and characterization of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing material by mechanical alloying process has been performed. The absorbing material was prepared by oxide materials, namely BaCO{sub 3}, La{sub 2}O{sub 3}, TiO{sub 2}, Fe{sub 2}O{sub 3}, and MnCO{sub 3}. The mixture was milled for 10 h and then sintered at a temperature of 1000 ° C for 10 h. The refinement results of x-ray diffraction pattern of lanthanum manganite substituted with barium showed that the sample consisted of two phases, namely, La{sub 0.9125}MnO{sub 3} phase which has a structure monoclinic (I12/a1) with lattice parameters a = 5.527(1) Å, b = 5.572(1) Å and c = 7.810(1) Å, α = γ = 90° and β = 89.88(5)°, the unit cell volume of V = 240.57(8) Å{sup 3}, and the atomic density of ρ = 6.238 gr.cm{sup −3}. The microstructure analyses showed that the particle shapes was polygonal with the varied particle sizes of 1 ∼ 3 μm distributed homogeneously on the surface of the samples. The results of the electromagnetic wave absorption curve analysis by using a vector network analyzer (VNA) showed that the sample can absorb microwaves in the frequency range of 8-15 GHz with a very wide absorption bandwidth. It indicates that the as prepared absorber presents potential absorbing property in X and Ku-band. We concluded that the (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} material can be applied as a candidate absorber material of microwaves or electromagnetic wave.

  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. Experimental measurement of effective atomic number of composite materials for Compton effect in the -ray region 280–1115 keV by a new method

    Indian Academy of Sciences (India)

    S Prasanna Kumar; T K Umesh

    2011-08-01

    In this paper, we report a new method to determine the effective atomic number, eff, of composite materials for Compton effect in the γ -ray region 280–1115 keV based on the theoretically obtained Klein–Nishina scattering cross-sections in the angular range 50°–100° as well as a method to experimentally measure differential incoherent (Compton) scattering cross-sections in this angular range. The method was employed to evaluate eff for different inorganic compounds containing elements in the range = 1–56, at three scattering angles 60°, 80° and 100° at three incident gamma energies 279.1 keV, 661.6 keV and 1115.5 keV and we have verified this method to be an appropriate method. Interestingly, the eff values so obtained for the inorganic compounds were found to be equal to the total number of electrons present in the sample as given by the atomic number of the elements constituting the sample in accordance with the chemical formula of the sample. This was the case at all the three energies.

  18. Quantification of differences in the effective atomic numbers of healthy and cancerous tissues: A discussion in the context of diagnostics and dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, M. L. [School of Applied Sciences and Health Innovation Research Institute, RMIT University, Melbourne 3000 (Australia); Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne 3001 (Australia) and Medical Physics, WBRC, Alfred Hospital, Melbourne 3000 (Australia)

    2012-09-15

    Purpose: There are a range of genetic and nongenetic factors influencing the elemental composition of different human tissues. The elemental composition of cancerous tissues frequently differs from healthy tissue of the same organ, particularly in high-Z trace element concentrations. For this reason, one could suggest that this may be exploited in diagnostics and perhaps even influence dosimetry. Methods: In this work, for the first time, effective atomic numbers are computed for common cancerous and healthy tissues using a robust, energy-dependent approach between 10 keV and 100 MeV. These are then quantitatively compared within the context of diagnostics and dosimetry. Results: Differences between effective atomic numbers of healthy and diseased tissues are found to be typically less than 10%. Fibrotic tissues and calcifications of the breast exhibit substantial (tens to hundreds of percent) differences to healthy tissue. Expectedly, differences are most pronounced in the photoelectric regime and consequently most relevant for kV imaging/therapy and radionuclides with prominent low-energy peaks. Cancerous tissue of the testes and stomach have lower effective atomic numbers than corresponding healthy tissues, while diseased tissues of the other organ sites typically have higher values. Conclusions: As dose calculation approaches improve in accuracy, there may be an argument for the explicit inclusion of pathologies. This is more the case for breast, penile, prostate, nasopharyngeal, and stomach cancer, less so for testicular and kidney cancer. The calculated data suggest dual-energy computed tomography could potentially improve lesion identification in the aforementioned organs (with the exception of testicular cancer), with most import in breast imaging. Ultimately, however, the differences are very small. It is likely that the assumption of a generic 'tissue ramp' in planning will be sufficient for the foreseeable future, and that the Z differences do

  19. Study of effective atomic number and electron density for tissues from human organs in the energy range of 1 keV-100 GeV.

    Science.gov (United States)

    Manjunatha, H C; Rudraswamy, B

    2013-02-01

    Effective atomic numbers' (Z(eff)) effective electron density (N(el)) for human organs and tissues have been computed in the energy region of 1 keV to 100 GeV using WinXCOM. The computed data of Z(eff) and N(el) are tabulated. The computed values are compared with previous results. The computed data of Z(eff)and N(el)for almost all tissues (34 tissues of different human organs) in the given energy range are not available in literature and find application in radiotherapy and dosimetry.

  20. Comparison of Martian meteorites with earth composition: Study of effective atomic numbers in the energy range 1 keV-100 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Ün, Adem, E-mail: ademun25@yahoo.com; Han, İbrahim, E-mail: ibrahimhan25@hotmail.com [Ağrı İbrahim Çeçen University, Faculty of Arts and Sciences, Department of Physics, 04100 Ağrı (Turkey); Ün, Mümine, E-mail: mun@agri.edu.tr [Ağrı İbrahim Çeçen University, Vocational School, Department of Electricity and Energy, 04100 Ağrz (Turkey)

    2016-04-18

    Effective atomic (Z{sub eff}) and electron numbers (N{sub eff}) for 24 Martian meteorites have been determined in the energy range from 1 keV to 100 GeV and also for sixteen significant energies of commonly used radioactive sources. The values of Z{sub eff} and N{sub eff} for all sample were obtained from the DirectZeff program. The obtained results for Martian meteorites have been compared with the results for Earth composition and similarities or differences also evaluated.

  1. 吸波材料与微波暗室问题的数学建模%Mathematical Modeling of Absorbing Materials and Microwave Dark Room

    Institute of Scientific and Technical Information of China (English)

    潘能渊; 胡爱杰; 汤振立

    2012-01-01

    power of dead zone get from signal source. This paper adopts dead zone extension method and construes the microwave dark room as a black box. Firstly, this paper establishes a cosine radiator spot radiation source to a bounded plane radiation model. Secondly, with this model, calculate the sum of all spot radiation sources to each dead zone virtual image radiation power, and establish the microwave dark room reflection model. The experiment indicate that flat absorbing materi-als(vertical reflectivity is 0.5) can not satisfy the seeker simulation requirement, meanwhile, the wedge absorbing material(vertical reflectivity is 0.05) can satisfy the seeker simulation requirement.

  2. Effective atomic numbers and electron densities of some human tissues and dosimetric materials for mean energies of various radiation sources relevant to radiotherapy and medical applications

    Science.gov (United States)

    Kurudirek, Murat

    2014-09-01

    Effective atomic numbers, Zeff, and electron densities, neff, are convenient parameters used to characterise the radiation response of a multi-element material in many technical and medical applications. Accurate values of these physical parameters provide essential data in medical physics. In the present study, the effective atomic numbers and electron densities have been calculated for some human tissues and dosimetric materials such as Adipose Tissue (ICRU-44), Bone Cortical (ICRU-44), Brain Grey/White Matter (ICRU-44), Breast Tissue (ICRU-44), Lung Tissue (ICRU-44), Soft Tissue (ICRU-44), LiF TLD-100H, TLD-100, Water, Borosilicate Glass, PAG (Gel Dosimeter), Fricke (Gel Dosimeter) and OSL (Aluminium Oxide) using mean photon energies, Em, of various radiation sources. The used radiation sources are Pd-103, Tc-99, Ra-226, I-131, Ir-192, Co-60, 30 kVp, 40 kVp, 50 kVp (Intrabeam, Carl Zeiss Meditec) and 6 MV (Mohan-6 MV) sources. The Em values were then used to calculate Zeff and neff of the tissues and dosimetric materials for various radiation sources. Different calculation methods for Zeff such as the direct method, the interpolation method and Auto-Zeff computer program were used and agreements and disagreements between the used methods have been presented and discussed. It has been observed that at higher Em values agreement is quite satisfactory (Dif.<5%) between the adopted methods.

  3. Effective atomic numbers of different types of materials for proton interaction in the energy region 1 keV-10 GeV

    Science.gov (United States)

    Kurudirek, Murat

    2014-10-01

    The effective atomic numbers (Zeff) of different types of materials such as tissues, tissue equivalents, organic compounds, glasses and dosimetric materials have been calculated for total proton interactions in the energy region 1 keV-10 GeV. Also, effective atomic numbers relative to water (Zeff RW) have been presented in the entire energy region for the materials that show better water equivalent properties. Some human tissues such as adipose tissue, bone compact, muscle skeletal and muscle striated have been investigated in terms of tissue equivalency by comparing Zeff values and the better tissue equivalents have been determined for these tissues. With respect to the variation of Zeff with kinetic energy, it has been observed that Zeff seems to be more or less the same in the energy region 400 keV-10 GeV for the given materials except for the photographic emulsion, calcium fluoride, silicon dioxide, aluminum oxide and Teflon. The values of Zeff have found to be constant for photographic emulsion after 1 GeV, for calcium fluoride between 1 MeV and 1 GeV and for silicon dioxide, aluminum oxide and Teflon between 400 keV and 1 GeV. This constancy clearly shows the availability of using Zeff in estimating radiation response of the materials at first glance.

  4. Effective atomic numbers of different types of materials for proton interaction in the energy region 1 keV–10 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.com

    2014-10-01

    The effective atomic numbers (Z{sub eff}) of different types of materials such as tissues, tissue equivalents, organic compounds, glasses and dosimetric materials have been calculated for total proton interactions in the energy region 1 keV–10 GeV. Also, effective atomic numbers relative to water (Z{sub eff}RW) have been presented in the entire energy region for the materials that show better water equivalent properties. Some human tissues such as adipose tissue, bone compact, muscle skeletal and muscle striated have been investigated in terms of tissue equivalency by comparing Z{sub eff} values and the better tissue equivalents have been determined for these tissues. With respect to the variation of Z{sub eff} with kinetic energy, it has been observed that Z{sub eff} seems to be more or less the same in the energy region 400 keV–10 GeV for the given materials except for the photographic emulsion, calcium fluoride, silicon dioxide, aluminum oxide and Teflon. The values of Z{sub eff} have found to be constant for photographic emulsion after 1 GeV, for calcium fluoride between 1 MeV and 1 GeV and for silicon dioxide, aluminum oxide and Teflon between 400 keV and 1 GeV. This constancy clearly shows the availability of using Z{sub eff} in estimating radiation response of the materials at first glance.

  5. Correlations between the two-phase gas/liquid spray atomization and the Stokes/aerodynamic Weber numbers

    Science.gov (United States)

    Rahman, Mohammad A.; Heidrick, Ted; Fleck, Brian A.

    2009-02-01

    The The effects of air-to-liquid ratio (β) and void fraction (α) on Sauter mean diameter (SMD or D32), arithmetic mean diameter (D10), surface mean diameter (D20), volume mean diameter (VMD or D20), and radial velocity profiles were experimentally investigated for a two-phase gas/liquid (TPGL) nozzle with a hybrid design of classical twin-fluid and effervescent nozzles. Radial spray profiles were measured using a Phase-Doppler-Particle-Anemometer (PDPA) system on 15Dn, 30Dn, 60Dn, 120Dn;(Dn represents nozzle diameter = 3.10,mm) axial distances. In addition, the effects of spray break-up patterns were analyzed with changing axial distances. The average void fraction in the feeding conduit (FC) was measured by a pneumatic controlled quick-closing-valve (QCV). The experiments were performed using mixtures of air with water at water flow rates of 1.50 to 7.50 kg/min and air-to-liquid mass ratios (β) of 0.30 to 10;%. The length and diameter of the FC was 36.8,cm and 6.35,mm, respectively. Result indicates that as the St number reaches the value of one, no more break-up continues, thus the droplets start to coalesce each other forming bigger droplets (higher D10 values) with increasing radial distances. Knowledge from this study will provide better understanding that ensures an increase in plant efficiency and product yield in oil sands bitumen upgrading.

  6. Effective atomic number and electron density of amino acids within the energy range of 0.122-1.330 MeV

    Science.gov (United States)

    More, Chaitali V.; Lokhande, Rajkumar M.; Pawar, Pravina P.

    2016-08-01

    Photon attenuation coefficient calculation methods have been widely used to accurately study the properties of amino acids such as n-acetyl-L-tryptophan, n-acetyl-L-tyrosine, D-tryptophan, n-acetyl-L-glutamic acid, D-phenylalanine, and D-threonine. In this study, mass attenuation coefficients (μm) of these amino acids for 0.122-, 0.356-, 0.511-, 0.662-, 0.884-, 1.170, 1.275-, 1.330-MeV photons are determined using the radio-nuclides Co57, Ba133, Cs137, Na22, Mn54, and Co60. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The calculated attenuation coefficient values were then used to determine total atomic cross sections (σt), molar extinction coefficients (ε), electronic cross sections (σe), effective atomic numbers (Zeff), and effective electron densities (Neff) of the amino acids. Theoretical values were calculated based on the XCOM data. Theoretical and experimental values are found to be in a good agreement (error<5%). The variations of μm, σt, ε, σe, Zeff, and Neff with energy are shown graphically. The values of μm, σt, ε, σe are higher at lower energies, and they decrease sharply as energy increases; by contrast, Zeff and Neff were found to be almost constant.

  7. Synthesis and Chiroptical Properties of Hexa-, Octa-, and Deca-azaborahelicenes: Influence of Helicene Size and of the Number of Boron Atoms.

    Science.gov (United States)

    Shen, Chengshuo; Srebro-Hooper, Monika; Jean, Marion; Vanthuyne, Nicolas; Toupet, Loïc; Williams, J A Gareth; Torres, Alexis R; Riives, Adrian J; Muller, Gilles; Autschbach, Jochen; Crassous, Jeanne

    2017-01-05

    Four members of a new class of cycloborylated hexa-, octa-, and deca-helicenes (1 a-d) have been prepared in enantiopure form, along with two cycloplatinated deca-helicenes (1 d', 1 d(1) ), further extending the family of cycloplatinated hexa- and octa-helicenes reported previously. The azabora[n]helicenes display intense electronic circular dichroism and large optical rotations; the dependence of the optical activity on the size of the helix (n=6, 8, 10) and the number of boron atoms (1 or 2) has been examined in detail both experimentally and theoretically. The photophysical properties (nonpolarized and circularly polarized luminescence) of these new fluorescent organic helicenes have been measured and compared with the corresponding organometallic phosphorescent cycloplatinated derivatives (1 a(1) -d(1) ).

  8. Investigation of the on-axis atom number density in the supersonic gas jet under high gas backing pressure by simulation

    Directory of Open Access Journals (Sweden)

    Guanglong Chen

    2015-10-01

    Full Text Available The supersonic gas jets from conical nozzles are simulated using 2D model. The on-axis atom number density in gas jet is investigated in detail by comparing the simulated densities with the idealized densities of straight streamline model in scaling laws. It is found that the density is generally lower than the idealized one and the deviation between them is mainly dependent on the opening angle of conical nozzle, the nozzle length and the gas backing pressure. The density deviation is then used to discuss the deviation of the equivalent diameter of a conical nozzle from the idealized deq in scaling laws. The investigation on the lateral expansion of gas jet indicates the lateral expansion could be responsible for the behavior of the density deviation. These results could be useful for the estimation of cluster size and the understanding of experimental results in laser-cluster interaction experiments.

  9. Effective atomic numbers and electron densities of bacteriorhodopsin and its comprising amino acids in the energy range 1 keV-100 GeV

    Science.gov (United States)

    Ahmadi, Morteza; Lunscher, Nolan; Yeow, John T. W.

    2013-04-01

    Recently, there has been an interest in fabrication of X-ray sensors based on bacteriorhodopsin, a proton pump protein in cell membrane of Halobacterium salinarium. Therefore, a better understanding of interaction of X-ray photons with bacteriorhodopsin is required. We use WinXCom program to calculate the mass attenuation coefficient of bacteriorhodopsin and its comprising amino acids for photon energies from 1 keV to 100 GeV. These amino acids include alanine, arginine, asparagine, aspartic acid, glutamine, glutamic acid, glycine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, Asx1, Asx2, Glx1 and Glx2. We then use that data to calculate effective atomic number and electron densities for the same range of energy. We also emphasize on two ranges of energies (10-200 keV and 1-20 MeV) in which X-ray imaging and radiotherapy machines work.

  10. Effective atomic numbers and electron densities of bacteriorhodopsin and its comprising amino acids in the energy range 1 keV–100 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, Morteza; Lunscher, Nolan [Waterloo Institute for Nanotechnology and Department of Systems Design Engineering, University of Waterloo, 200 University Ave., W., Waterloo, Ontario, Canada N2L 3G1 (Canada); Yeow, John T.W., E-mail: jyeow@uwaterloo.ca [Waterloo Institute for Nanotechnology and Department of Systems Design Engineering, University of Waterloo, 200 University Ave., W., Waterloo, Ontario, Canada N2L 3G1 (Canada)

    2013-04-01

    Recently, there has been an interest in fabrication of X-ray sensors based on bacteriorhodopsin, a proton pump protein in cell membrane of Halobacterium salinarium. Therefore, a better understanding of interaction of X-ray photons with bacteriorhodopsin is required. We use WinXCom program to calculate the mass attenuation coefficient of bacteriorhodopsin and its comprising amino acids for photon energies from 1 keV to 100 GeV. These amino acids include alanine, arginine, asparagine, aspartic acid, glutamine, glutamic acid, glycine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, Asx1, Asx2, Glx1 and Glx2. We then use that data to calculate effective atomic number and electron densities for the same range of energy. We also emphasize on two ranges of energies (10–200 keV and 1–20 MeV) in which X-ray imaging and radiotherapy machines work.

  11. Application of FMBEM to calculation of sound fields in sound-absorbing materials%快速多极子边界元法在吸声材料声场计算中的应用

    Institute of Scientific and Technical Information of China (English)

    崔晓兵; 季振林

    2011-01-01

    The numerical calculation of multipole expansions in FMBEM was investigated, and the models of four points translation relationships at single level and multi-levels were built. According to the variation of theoretical values of Green's function and its normal derivative, the computational accuracy of multipole expansions in sound-absorbing materials and in air medium was compared under the two different translation relationships respectively. The results indicate that, the computational accuracy, which is derived from the calculation of expansions with complex wavenumber, is related to the number of truncated terms. When the product of the wavenumber's imaginary part and the distance between transitive points is too big, the expansion's value begins to go far away from the true value. Two methods were proposed to solve this problem. Furthermore, the transmission loss of a silencer with dissipative expansion chamber was calculated as an example and the availability and feasibility of the methods presented were validated.%对快速多极子边界元法中多极子展开式的数值计算进行了研究,建立四点单级传递关系与多级传递关系模型.通过与格林函数及其法向导数理论值的比较,考察两种传递情况下,多极子展开式在吸声材料介质及空气介质中的计算精度.结果表明,复波数展开式的求解精度与截断项数的大小相关,而且当复波数虚部值与展开点间距离乘积过大时,展开式值开始与真值相背离.最后提出了解决此问题的两种方法.此外,以膨胀腔阻性消声器传递损失计算为例,验证了该方法的有效性与可行性.

  12. Atomic Calligraphy

    Science.gov (United States)

    Imboden, Matthias; Pardo, Flavio; Bolle, Cristian; Han, Han; Tareen, Ammar; Chang, Jackson; Christopher, Jason; Corman, Benjamin; Bishop, David

    2013-03-01

    Here we present a MEMS based method to fabricate devices with a small number of atoms. In standard semiconductor fabrication, a large amount of material is deposited, after which etching removes what is not wanted. This technique breaks down for structures that approach the single atom limit, as it is inconceivable to etch away all but one atom. What is needed is a bottom up method with single or near single atom precision. We demonstrate a MEMS device that enables nanometer position controlled deposition of gold atoms. A digitally driven plate is swept as a flux of gold atoms passes through an aperture. Appling voltages on four comb capacitors connected to the central plate by tethers enable nanometer lateral precision in the xy plane over 15x15 sq. microns. Typical MEMS structures have manufacturing resolutions on the order of a micron. Using a FIB it is possible to mill apertures as small as 10 nm in diameter. Assuming a low incident atomic flux, as well as an integrated MEMS based shutter with microsecond response time, it becomes possible to deposit single atoms. Due to their small size and low power consumption, such nano-printers can be mounted directly in a cryogenic system at ultrahigh vacuum to deposit clean quench condensed metallic structures.

  13. Extrapolation of the Bethe equation for electron stopping powers to intermediate and low electron energies by empirical simulation of target effective mean excitation energy and atomic number

    Energy Technology Data Exchange (ETDEWEB)

    Maglevanny, I.I., E-mail: sianko@list.ru [Volgograd State Social Pedagogical University, 27 Lenin Avenue, Volgograd 400131 (Russian Federation); Smolar, V.A.; Nguyen, H.T.T. [Volgograd State Technical University, 28 Lenin Avenue, Volgograd 400131 (Russian Federation)

    2013-12-01

    A series of simple stopping power (SP) formulas, modified from the relativistic Bethe equation, is presented that is based on the concepts of target effective atomic number and mean excitation energy (MEE). The analytical model function is constructed to approximate experimental or calculated SPs at low electron energies and tend asymptotically to the relativistic Bethe function at high energies. The energy dependencies of our effective values, in contrast with theoretical approaches, are defined empirically by parametrization with tuning parameters. A least-squares fitting routine based on the Levenberg–Marquardt algorithm was developed. We utilize the material parameters and numerical calculations of SPs from optical data using the full Penn-algorithm. Our formula is thought to be applicable for energies above 60 eV. Our simulations of SPs for 41 elemental solids are found to be in good agreement with published numerical results. The flexibility of a general empirical formula is shown. Shortened formulas were developed that are applicable for particular energy ranges, and effective MEEs are proposed that differ from previously recommended values. The presented formulas may be used for analytical calculation of SPs over a broad projectile energy region.

  14. Chemical composition, effective atomic number and electron density study of trommel sieve waste (TSW), Portland cement, lime, pointing and their admixtures with TSW in different proportions.

    Science.gov (United States)

    Kurudirek, Murat; Aygun, Murat; Erzeneoğlu, Salih Zeki

    2010-06-01

    The trommel sieve waste (TSW) which forms during the boron ore production is considered to be a promising building material with its use as an admixture with Portland cement and is considered to be an alternative radiation shielding material, also. Thus, having knowledge on the chemical composition and radiation interaction properties of TSW as compared to other building materials is of importance. In the present study, chemical compositions of the materials used have been determined using a wavelength dispersive X-ray fluorescence spectrometer (WDXRFS). Also, TSW, some commonly used building materials (Portland cement, lime and pointing) and their admixtures with TSW have been investigated in terms of total mass attenuation coefficients (mu/rho), photon interaction cross sections (sigma(t)), effective atomic numbers (Z(eff)) and effective electron densities (N(e)) by using X-rays at 22.1, 25keV and gamma-rays at 88keV photon energies. Possible conclusions were drawn with respect to the variations in photon energy and chemical composition.

  15. Determination of effective atomic number of breast tissues using scattered radiation; Determinacao do numero atomico efetivo de tecidos mamarios usando a radiacao espalhada

    Energy Technology Data Exchange (ETDEWEB)

    Antoniassi, M.; Conceicao, A.L.C.; Poletti, M.E. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Fac. de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2010-07-01

    The scattered radiation has been used in several industrial and clinical applications since it permits to characterize the scattering material. Several types of information can be extracted from the spectrum of scattered radiation which can be used to characterization of biological tissues such as breast tissues. In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose), benign (fibroadenoma) and malignant (carcinoma) neoplastic breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90 deg C (x = 0.99 angstrom-1). A practical method using the area of elastic and inelastic scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated comparing the experimental obtained values of Z{sub eff} of several standard materials with calculated values using traditional method based on total cross-section of compounds. The obtained results show that exist differences in the distributions of Z{sub eff} of breast tissues, which are related to the content of carbon (Z=6) and oxygen (Z=8) in each tissue type. The results suggest that is possible to use this parameter for characterizing breast tissues, pointing the possibility of its use as a complementary tool for the diagnosis of the breast cancer. (author)

  16. The atomic orbitals of the topological atom.

    Science.gov (United States)

    Ramos-Cordoba, Eloy; Salvador, Pedro; Mayer, István

    2013-06-07

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure.

  17. 蜂窝夹芯吸波材料电磁特性研究进展%Research development on electromagnetic properties of honeycomb sandwich wave-absorbing materials

    Institute of Scientific and Technical Information of China (English)

    常霞; 袁昊; 高正平

    2013-01-01

    Due to light weight, high strength and stiffness, good absorbing capacity and other advantages, the absorbing materials with honeycomb sandwich structure are widely used in the military. Foreign research on this field is mature, but relevant literatures are rare for confidentiality. Most domestic researches pay more attenation to mechanic performance of the structure than electromagnetism. This paper introduces honeycomb sandwich absorbing material from different research methods at home and abroad.%由于蜂窝夹芯结构吸波材料具有重量轻、强度和刚度大、吸波性能好等多个优点,在军事应用上受到广泛的关注。国外在此方面研究较成熟,但出于保密,能查到的相关文献很少。而国内对蜂窝夹芯结构多是从力学角度去研究,从电磁学角度研究相对较少。从不同研究方法的角度介绍了目前国内外蜂窝夹芯吸波材料电磁特性方面的研究进展。

  18. Thin films of absorber material Cu2ZnSnS4 for solar cells

    DEFF Research Database (Denmark)

    Cazzaniga, Andrea Carlo; Ettlinger, Rebecca Bolt; Schou, Jørgen

    2014-01-01

    in intensity. Optical measurements (direct and diffusereflectance) and ellipsometry analysis are used to investigate the optical constants of the films produced and to estimate the bandgap, while AFM images are used to investigate the roughness.The same measurements are carried out on the same samples after......Pulsed Laser Deposition technique is applied to the production of thin films of CZTS (Cu2ZnSnS4).This vacuum technique has proven to be particularly successful in the production of films with acomplex stoichiometry, as in the case of high temperature superconductors. The material ablated bythe...... laser pulse is transferred to the substrate at very high kinetic energy (~ keV), thus resulting inhigh mobility of the adsorpted atoms yet at low substrate temperatures. Since the reaction ofdecomposition of CZTS via S and SnS evaporation is the main problem all vacuum techniques haveto deal with...

  19. On the calculation of line strengths, oscillator strengths and lifetimes for very large principal quantum numbers in hydrogenic atoms and ions by the McLean-Watson formula

    Science.gov (United States)

    Hey, J. D.

    2014-08-01

    As a sequel to an earlier study (Hey 2009 J. Phys. B: At. Mol. Opt. Phys. 42 125701), we consider further the application of the line strength formula derived by Watson (2006 J. Phys. B: At. Mol. Opt. Phys. 39 L291) to transitions arising from states of very high principal quantum number in hydrogenic atoms and ions (Rydberg-Rydberg transitions, n > 1000). It is shown how apparent difficulties associated with the use of recurrence relations, derived (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641) by the ladder operator technique of Infeld and Hull (1951 Rev. Mod. Phys. 23 21), may be eliminated by a very simple numerical device, whereby this method may readily be applied up to n ≈ 10 000. Beyond this range, programming of the method may entail greater care and complexity. The use of the numerically efficient McLean-Watson formula for such cases is again illustrated by the determination of radiative lifetimes and comparison of present results with those from an asymptotic formula. The question of the influence on the results of the omission or inclusion of fine structure is considered by comparison with calculations based on the standard Condon-Shortley line strength formula. Interest in this work on the radial matrix elements for large n and n‧ is related to measurements of radio recombination lines from tenuous space plasmas, e.g. Stepkin et al (2007 Mon. Not. R. Astron. Soc. 374 852), Bell et al (2011 Astrophys. Space Sci. 333 377), to the calculation of electron impact broadening parameters for such spectra (Watson 2006 J. Phys. B: At. Mol. Opt. Phys. 39 1889) and comparison with other theoretical methods (Peach 2014 Adv. Space Res. in press), to the modelling of physical processes in H II regions (Roshi et al 2012 Astrophys. J. 749 49), and the evaluation bound-bound transitions from states of high n during primordial cosmological recombination (Grin and Hirata 2010 Phys. Rev. D 81 083005, Ali-Haïmoud and Hirata 2010 Phys. Rev. D 82 063521, Ali

  20. A study of effective atomic number and electron density of gel dosimeters and human tissues for scattering of gamma rays: momentum transfer, energy and scattering angle dependence.

    Science.gov (United States)

    Kurudirek, Murat

    2016-11-01

    The objective of this work was to study water- and tissue-equivalent properties of some gel dosimeters, human tissues and water, for scattering of photons using the effective atomic number (Z eff). The Rayleigh to Compton scattering ratio (R/C) was used to obtain Z eff and electron density (N e ) of gel dosimeters, human tissues and water considering a 10(-2)-10(9) momentum transfer, q (Å(-1)). In the present work, a logarithmic interpolation procedure was used to estimate R/C as well as Z eff of the chosen materials in a wide scattering angle (1°-180°) and energy range (0.001-100 MeV). The Z eff of the chosen materials was found to increase as momentum transfer increases, for q > ~1 Å(-1). At fixed scattering angle and energy, Z eff of the material first increases and then becomes constant for high momentum transfers (q ≥ 3 Å(-1)), which indicates that Z eff is almost independent of energy and scattering angle for the chosen materials. Based on the Z eff data and the continuous momentum transfer range (10(-2)-10(9) Å(-1)), MAGIC, PAGAT and soft tissue were found to be water-equivalent materials, since their differences (%) relative to water are significantly low (≤3.2 % for MAGIC up to 10(3) Å(-1), ≤2.9 % for PAGAT up to 10(9) Å(-1), and ≤3.8 % for soft tissue up to 10(9) Å(-1)), while the Fricke gel was not found to be water equivalent. PAGAT was found to be a soft tissue-equivalent material in the entire momentum transfer range (<4.3 %), while MAGAT has shown to be tissue equivalent for brain (≤8.1 % up to 10 Å(-1)) and lung (<8.2 % up to 10 Å(-1)) tissues. The Fricke gel dosimeter has shown to be adipose tissue equivalent for most of the momentum range considered (<10 %).

  1. A Review of Electromagnetic Wave Absorbing Materials Used in Microwave Deicing Pavement%电磁波吸收材料用于微波融冰雪路面的研究进展∗

    Institute of Scientific and Technical Information of China (English)

    高杰; 张正伟; 韩振强; 沙爱民; 王振军; 蒋玮

    2016-01-01

    Microwave deicing pavement is manufactured by electromagnetic wave absorbing materials and the traditional pavement,which has broad application prospects because of its advantages of efficiency and eco-friendli-ness.In order to further increase the deicing ability of microwave deicing pavement,the working principle of the mi-crowave deicing pavement and the main factors influencing the deicing efficiency are introduced in this paper.Micro-wave heating mechanism of electromagnetic wave absorbing materials is elaborated.And the electromagnetic charac-teristics of 9 microwave absorbing materials are summarized.The research progresses of carbon fiber,magnetite and steel fiber in microwave deicing pavement are emphatically introduced,and their application prospects are evaluated re-spectively from the viewpoint of economic efficiency and heating rate .At last,the current drawbacks existing in this technology are pointed out.%电磁波吸收材料与传统路面材料相结合,所形成的微波融冰雪路面具有高效、环保等优势。为进一步提高路面的微波融冰雪能力,介绍了微波融冰雪路面的工作原理及影响除冰效率的主要因素,阐述了电磁波吸收材料在微波照射下的发热机理。在此基础上,综述了9种电磁波吸收材料的电磁特性,并着重介绍了碳纤维、磁铁矿石与钢纤维用于路面微波除冰雪的研究进展,并从发热速率与经济性角度对比分析其应用前景。最后,指出了目前研究中存在的问题,展望了今后的研究趋势。

  2. Development of New Absorber Materials to Achieve Organic Photovoltaic Commercial Modules with 15% Efficiency and 20 Years Lifetime: Cooperative Research and Development Final Report, CRADA Number CRD-12-498

    Energy Technology Data Exchange (ETDEWEB)

    Olson, D.

    2014-08-01

    Under this CRADA the parties will develop intermediates or materials that can be employed as the active layer in dye sensitized solar cells printed polymer systems, or small molecule organic photovoltaics.

  3. Fast kVp-switching dual energy contrast-enhanced thorax and cardiac CT: A phantom study on the accuracy of iodine concentration and effective atomic number measurement.

    Science.gov (United States)

    Papadakis, Antonios E; Damilakis, John

    2017-09-01

    To assess the effect of vessel diameter and exposure parameters on the estimation accuracy of concentration and effective atomic number (Zeff ) of iodine (I) in contrast-enhanced thorax and cardiac dual-energy CT using a modern fast kVp-switching CT scanner. A standard semi-anthropomorphic cardiac CT phantom devised to simulate the human chest at three different body habitus i.e., medium-sized, large-sized, and obese, was scanned using a fast kVp-switching Revolution-GSI GE CT scanner. Five cylindrical, 10 mm diameter, vials were filled with solutions prepared by diluting I contrast at five concentrations (2.5, 5, 10, 15, and 20 mg I/ml). To simulate small vessels, pipette tips with a diameter ranging from 5 mm to 0.5 mm were employed. The vials and pipette tips were accommodated within the semi-anthropomorphic phantom. CT acquisitions were performed in the fast kVp-switching dual-energy mode at six different CTDIw values. Acquisitions were also performed at 80, 100, 120, and 140 kVp. Images were acquired at 64 × 0.625 mm beam collimation and reconstructed at 2.5 mm using all available reconstruction filter kernels. Virtual monochromatic spectral (VMS) images, iodine concentration (IMeas ), and Zeff maps were reconstructed. Hounsfield unit as a function of energy (HUkeV ) in VMS and single-kVp (HUkVp ), IMeas and Zeff were measured at each CTDIw . The effect of vessel diameter on IMeas and Zeff was investigated. Measured HUkeV and Zeff were compared to theoretically estimated values and IMeas were compared to nominal (INom ) values. In 10 mm diameter vessels, HUkeV values were accurate to 18% for the medium-sized, 22% for the large-sized and 39% for the obese phantoms. IMeas was underestimated by up to 10% for the medium-sized, 26% for the large-sized and 33% for the obese phantom. IMeas error decreased with increasing CTDIw from ±0.799 mg/ml at 8.61 mGy to ±0.082 mg/ml at 32.01 mGy. The percentage difference between measured and theoretically estimated Zeff

  4. International Journal of Quantum Chemistry. Quantum Chemistry Symposium Number 27: Proceedings of the International Symposium on Atomic, Molecular, and Condensed Matter Theory and Computational Methods Held in St. Augustine, Florida on 13-20 March 1993

    Science.gov (United States)

    1993-03-20

    defining a transition for a certain number of atoms that depends * Permanent address. Proyecto Quinor, Facultad de Ciencias Exactas , Universidad Nacional...Universidade Federal de Uberlandia 205 CPL PRC Depto. de Ciencias Fisicas Bartlesv2le, OK 74004 Campus Santa Monica Uberlandia, MG 38400-902 RICHARD...considering the tip, sample and * On leave from: Escuela de Quimica, Facultad de Ciencias . Universidad Central de Venezuela. Apar- tado 47102, Caracas 1020 A

  5. Number series of atoms, interatomic bonds and interface bonds defining zinc-blende nanocrystals as function of size, shape and surface orientation: Analytic tools to interpret solid state spectroscopy data

    Directory of Open Access Journals (Sweden)

    Dirk König

    2016-08-01

    Full Text Available Semiconductor nanocrystals (NCs experience stress and charge transfer by embedding materials or ligands and impurity atoms. In return, the environment of NCs experiences a NC stress response which may lead to matrix deformation and propagated strain. Up to now, there is no universal gauge to evaluate the stress impact on NCs and their response as a function of NC size dNC. I deduce geometrical number series as analytical tools to obtain the number of NC atoms NNC(dNC[i], bonds between NC atoms Nbnd(dNC[i] and interface bonds NIF(dNC[i] for seven high symmetry zinc-blende (zb NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra, {001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and {001}-{111} quadrodecahedra. The fundamental insights into NC structures revealed here allow for major advancements in data interpretation and understanding of zb- and diamond-lattice based nanomaterials. The analytical number series can serve as a standard procedure for stress evaluation in solid state spectroscopy due to their deterministic nature, easy use and general applicability over a wide range of spectroscopy methods as well as NC sizes, forms and materials.

  6. Number series of atoms, interatomic bonds and interface bonds defining zinc-blende nanocrystals as function of size, shape and surface orientation: Analytic tools to interpret solid state spectroscopy data

    Science.gov (United States)

    König, Dirk

    2016-08-01

    Semiconductor nanocrystals (NCs) experience stress and charge transfer by embedding materials or ligands and impurity atoms. In return, the environment of NCs experiences a NC stress response which may lead to matrix deformation and propagated strain. Up to now, there is no universal gauge to evaluate the stress impact on NCs and their response as a function of NC size dNC. I deduce geometrical number series as analytical tools to obtain the number of NC atoms NNC(dNC[i]), bonds between NC atoms Nbnd(dNC[i]) and interface bonds NIF(dNC[i]) for seven high symmetry zinc-blende (zb) NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra, {001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and {001}-{111} quadrodecahedra. The fundamental insights into NC structures revealed here allow for major advancements in data interpretation and understanding of zb- and diamond-lattice based nanomaterials. The analytical number series can serve as a standard procedure for stress evaluation in solid state spectroscopy due to their deterministic nature, easy use and general applicability over a wide range of spectroscopy methods as well as NC sizes, forms and materials.

  7. The structure, properties, and nature of HArF-benzene complex: redshift and blueshift of Ar-H stretch frequency and rare gas atomic number dependence of hydrogen bonds.

    Science.gov (United States)

    Liu, Xiaofeng; Li, Qingzhong; Li, Ran; Li, Wenzuo; Cheng, Jianbo

    2011-12-15

    Ab initio calculations have been performed for the complexes of benzene with HArF, HKrF, and HXeF. The computed results indicate that the complexes of benzene-HArF exist in different conformations and among them those with π-hydrogen bonds are the more stable than those with C-H···F hydrogen bonds. Interestingly, the Ar-H stretching frequency is redshifted in the more stable isomer and blueshifted in the less stable form. The Ng (Ng=Ar, Kr, and Xe) atomic number dependence of the Ng-H···π and C-H···F hydrogen bonds has been explored. The result indicates that the strength of Ng-H···π and C-H···F hydrogen bonds is weakened with the increase of Ng atomic number. Natural bond orbital analysis has been performed to understand the interaction nature, frequency shift of H-Ng stretch, and dependence of Ng-H···π and C-H···F hydrogen bonds on the Ng atomic number.

  8. Combination of the ionic-to-atomic line intensity ratios from two test elements for the diagnostic of plasma temperature and electron number density in Inductively Coupled Plasma Atomic Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tognoni, E. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: tognoni@ipcf.cnr.it; Hidalgo, M.; Canals, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia. Universidad de Alicante. Apdo. 99, 03080, Alicante (Spain); Cristoforetti, G.; Legnaioli, S.; Salvetti, A.; Palleschi, V. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)

    2007-05-15

    In Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) spectrochemical analysis, the MgII(280.270 nm)/MgI(285.213 nm) ionic to atomic line intensity ratio is commonly used as a monitor of the robustness of operating conditions. This approach is based on the univocal relationship existing between intensity ratio and plasma temperature, for a pure argon atmospheric ICP in thermodynamic equilibrium. In a multi-elemental plasma in the lower temperature range, the measurement of the intensity ratio may not be sufficient to characterize temperature and electron density. In such a range, the correct relationship between intensity ratio and plasma temperature can be calculated only when the complete plasma composition is known. We propose the combination of the line intensity ratios of two test elements (double ratio) as an effective diagnostic tool for a multi-elemental low temperature LTE plasma of unknown composition. In particular, the variation of the double ratio allows us discriminating changes in the plasma temperature from changes in the electron density. Thus, the effects on plasma excitation and ionization possibly caused by introduction of different samples and matrices in non-robust conditions can be more accurately interpreted. The method is illustrated by the measurement of plasma temperature and electron density in a specific analytic case.

  9. Research on porous sound-absorbing materials by the secondary cracking fraction of cracked residue of waste silicone rubbers%废硅橡胶二次裂解渣制多孔吸声材料的研究

    Institute of Scientific and Technical Information of China (English)

    吕春丽; 范磊; 王明贤

    2011-01-01

    采用吸声材料是吸声、降噪、改善声环境的有效手段.本文研究用废旧硅橡胶二次裂解渣和粘结剂为主要原料,采用压制成型的工艺,在常温下制成一种多孔吸声材料.主要考虑残渣里的硅烷类油份和所用发泡剂对试件吸声性能的影响.试验结果表明:所制吸声材料能达到一定的吸声性能,具有对环境无污染,施工方便等优点;且分离出硅烷类油份的灰渣所制试件比原废旧硅橡胶裂解残渣的吸声效果好很多,尤其在共振频率1250Hz下达到吸声峰值0.87.FP - 186植物性水泥发泡剂相比FP- 180动物性水泥发泡剂对试件吸声性能有所改善,使吸声特性曲线向低频方向移动.%With the development of the economic and society in our country, people's living standards are increasing. People demand higher quality of life environment in city, and draw attention on the noise reduction and the improvement of the acoustic environment, increasingly. Sound-absorbing material is an effective means of sound absorption and improving the acoustic environment. In this paper, the porous absorbing material were made by press forming technique at room temperature incorporatly with binder and the secondary cracked residue of waste silicone rubbers. The influences of oil portion of silanes and foaming agent on sound absorption of the porous absorbing material were investigated. The material showed the characteristics of low cost of preparation and non-pollution to the environment. The results showed that the sound absorbing effect of the specimens made by ash and slag, separated from oil portion of silanes was better than the specimens made by cracked residue of waste silicone rubbers, especially when the resonant frequency was 1250Hz,product sound absorption coefficient could be 0. 87. The specimens adding FP - 186 botanical cement foaming agent showed a good improvement of the sound absorbing effect than FP -180 animalic cement foaming agent

  10. Electrochemical Corrosion Testing of Neutron Absorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Tedd Lister; Ron Mizia; Arnold Erickson; Tammy Trowbridge

    2007-05-01

    This report summarizes the results of crevice-corrosion tests for six alloys in solutions representative of ionic compositions inside the Yucca Mountain waste package should a breech occur. The alloys in these tests are Neutronit A978a (ingot metallurgy, hot rolled), Neutrosorb Plus 304B4 Grade Ab (powder metallurgy, hot rolled), Neutrosorb Plus 304B5 Grade Ab (powder metallurgy, hot rolled), Neutrosorb Plus 304B6 Grade Ab (powder metallurgy, hot rolled), Ni-Cr-Mo-Gd alloy2 (ingot metallurgy, hot rolled), and Alloy 22 (ingot metallurgy, hot rolled).

  11. New Solutions for Energy Absorbing Materials

    Science.gov (United States)

    2012-11-01

    cristobalite samples ................................................................................. 45 4.2.4 Microscopy...45 4.2.5 Quasistatic Mechanical Testing of α- cristobalite ...NPR materials selected and why they are of interest The inclusions selected for this project are α- cristobalite and samples produced from auxetic

  12. Kβ/Kα X-ray intensity ratios for some elements in the atomic number range 28≤Z≤39 at 16.896 keV

    Directory of Open Access Journals (Sweden)

    R. Yılmaz

    2017-07-01

    Full Text Available The K shell intensity ratios (Kβ/Kα have been experimentally determined for some elements in the atomic number range 28 ≤ Z ≤ 39 by using secondary excitation method. K X-rays emitted by samples have been counted by a Si (Li detector with 160 eV resolutions at 5.9 keV. The measured values were compared with the theoretical and experimental values. In general, the values obtained are in good agreement with the calculated values.

  13. Accurate Atom Counting in Mesoscopic Ensembles

    CERN Document Server

    Hume, D B; Joos, M; Muessel, W; Strobel, H; Oberthaler, M K

    2013-01-01

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  14. Accurate Atom Counting in Mesoscopic Ensembles

    Science.gov (United States)

    Hume, D. B.; Stroescu, I.; Joos, M.; Muessel, W.; Strobel, H.; Oberthaler, M. K.

    2013-12-01

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  15. Accurate atom counting in mesoscopic ensembles.

    Science.gov (United States)

    Hume, D B; Stroescu, I; Joos, M; Muessel, W; Strobel, H; Oberthaler, M K

    2013-12-20

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  16. Water equivalence study of some phantoms based on effective photon energy, effective atomic numbers and electron densities for clinical MV X-ray and Co-60 γ-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.com [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)

    2013-02-11

    A previously proposed procedure has been applied to some water equivalent phantoms namely PMMA, Polystyrene, Solid Water (WT1), RW3 and ABS for the first time to compute effective photon energy (E{sub eff}), effective atomic numbers (Z{sub eff}) and electron densities (ne{sub eff}) for different MV X-ray beams and Co-60 gamma beam which are heterogeneous in energy. For the purpose of the present investigation, effective atomic cross-sections of the given materials have been determined first to obtain effective photon energies which were further used for calculation of Z{sub eff} and ne{sub eff}. Similar procedure was adopted for Co-60 γ-rays to check the validity of the present method. Results were found to be quite satisfactory. When it comes to the water equivalence, the E{sub eff} results showed that the RW3 and ABS phantoms are more effective for 6 MV beam whereas RW3 and Polystyrene are more effective for 15 MV and Co-60 beams, respectively. The ABS and WT1 phantoms have better water equivalences than the others according to the Z{sub eff} and ne{sub eff} results, respectively.

  17. Coaxial airblast atomizers

    Science.gov (United States)

    Hardalupas, Y.; Whitelaw, J. H.

    1993-01-01

    An experimental investigation was performed to quantify the characteristics of the sprays of coaxial injectors with particular emphasis on those aspects relevant to the performance of rocket engines. Measurements for coaxial air blast atomizers were obtained using air to represent the gaseous stream and water to represent the liquid stream. A wide range of flow conditions were examined for sprays with and without swirl for gaseous streams. The parameters varied include Weber number, gas flow rate, liquid flow rate, swirl, and nozzle geometry. Measurements were made with a phase Doppler velocimeter. Major conclusions of the study focused upon droplet size as a function of Weber number, effect of gas flow rate on atomization and spray spread, effect of nozzle geometry on atomization and spread, effect of swirl on atomization, spread, jet recirculation and breakup, and secondary atomization.

  18. Effective atomic numbers, water and tissue equivalence properties of human tissues, tissue equivalents and dosimetric materials for total electron interaction in the energy region 10 keV-1 GeV.

    Science.gov (United States)

    Kurudirek, Murat

    2014-12-01

    Effective atomic numbers (Zeff) of 107 different materials of dosimetric interest have been calculated for total electron interactions in the wide energy region 10keV-1GeV. The stopping cross sections of elements and dosimetric materials were used to calculate Zeff of the materials. Differences (%) in Zeff relative to water have been calculated in the entire energy region to evaluate the water equivalency of the used materials. Moreover, the tissue equivalent materials have been compared with the tissues and dosimetric materials in terms of Zeff to reveal their ability to use as tissue substitutes. Possible conclusions were drawn based on the variation of Zeff through the entire energy region and water and tissue equivalency comparisons in terms of Zeff. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Energy dependence of effective atomic numbers for photon energy absorption and photon interaction: Studies of some biological molecules in the energy range 1 keV-20 MeV

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2008-01-01

    Effective atomic numbers for photon energy absorption, Z(PEA,eff), and for photon interaction, Z(PI,eff), have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for biological molecules, such as fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic...... dependence of the mass attenuation coefficient, Z(PEA, eff), and the mass energy-absorption coefficient, Z(PI, eff), is shown graphically and in tabular form. Significant differences of 17%-38% between Z(PI, eff) and Z(PEA, eff) occur in the energy region 5-100 keV. The reasons for these differences...

  20. Study on sound absorption properties of nonwoven sound-absorbing material in highway sound barrier%高速公路声屏障用非织造吸声材料的吸声性能研究

    Institute of Scientific and Technical Information of China (English)

    钱薇薇; 张瑜; 高强; 李伟岸; 许君海

    2013-01-01

      The most effective measure to solve the noise problem of the traffic network is to set the sound barrier . Comparing other sound barrier materials, nonwoven material has its unique advantages .The sound-absorbing performance of polyester needle-punched nonwoven sound-absorbing materials on middle and low frequency of 250 ~2 000 Hz was studied and composition and cross-sectional of fiber, material thickness and process on effect to material sound-absorbing properties were analyzed .The result was that the materials made of hollow fiber and fine denier fiber have better sound-absorbing effect, the thickness of material effect sound-absorbing properties obviously , and hot melt calendar and surface treatment have proper active effect on the sound-absorbing property.%  目前解决交通路网噪声问题的最有效措施是设置道路声屏障。在众多声屏障吸声材料中,非织造材料有其特有的优点。研究了涤纶针刺非织造吸声材料在250~2000 Hz中低声频范围内的吸声性能,分析了纤维的组成和横截面、材料厚度以及加工工艺等因素对材料吸声性能的影响。结果表明:在所制备的吸声材料中,由细旦纤维和中空纤维制成的材料具有较好的吸声效果,材料的厚度对吸声性能的影响比较明显,热熔加固和表面处理对材料的吸声性能也有一定的积极作用。

  1. Study on absorption performance of new wave-absorbering material nano-compound-α-Fe%新型吸波剂纳米复合α-Fe的吸波性能研究

    Institute of Scientific and Technical Information of China (English)

    廖晓莲; 谭新常; 李正南

    2014-01-01

    探讨了利用天然马脾铁蛋白制备的核壳型纳米复合粉末的成分及组织结构、纳米复合α-Fe含量对电磁参数及电磁损耗的影响,以及以纳米复合α-Fe作为吸波剂的吸收性能。结果表明:利用天然马脾铁蛋白可以制备粒径均一的核壳型纳米复合α-Fe ,一次粒径小于12 nm ;随着复合α-Fe含量的增加,介电常数ε′和ε″基本上单调增加,同时有助于磁导率μ′和μ″的提高;电磁损耗单调增加,损耗中以电损耗为主,磁损耗次之。用纳米复合α-Fe作为吸波剂,可以在厘米波范围内取得较理想的吸收效果,是一种新型的、耐腐蚀性能好的纳米吸波材料。%The composition and structure of the core shell structured nano-composites are analyzed by using natural horse spleen ferritin as materials . The impact of nano-composition α-Fe on the electromagnetic parameters and the electromagnetic loss ,the absorbability of nano-composites-α-Fe as wave-absorber is studied as well .The results show that using natural horse spleen ferritin can prepare the core shell structured nano-composites-α-Fe with equidimensional particle-size and the linear particle-size is less than 12 nm .Theε′andε″raise monotonously and at the same time contribute to the rise of μ′and μ″with the increase of compound-α-Fe . The electromagnetic loss is also raised monotonously with the increase of compound-α-Fe ,with the electric loss as the main loss and the magnetic loss as the second loss .Utilization of the nano-composites-α-Fe as wave-absorber can obtain an ideal absorbent effect within the range of centimeter wave .From all these results ,it is concluded that the nano-composites-α-Fe is a new nano-absorbing material having good performances with good corrosion resistance .

  2. Effective atomic number, energy loss and radiation damage studies in some materials commonly used in nuclear applications for heavy charged particles such as H, C, Mg, Fe, Te, Pb and U

    Science.gov (United States)

    Kurudirek, Murat

    2016-05-01

    Commonly used nuclear physics materials such as water, concrete, Pb-glass, paraffin, freon and P 10 gases, some alloys such as brass, bronze, stainless-steel and some scintillators such as anthracene, stilbene and toluene have been investigated with respect to the heavy charged particle interaction as means of projected range and effective atomic number (Zeff) in the energy region 10 keV to 10 MeV. Calculations were performed for heavy ions such as H, C, Mg, Fe, Te, Pb and U. Also, the energy loss and radiation damage were studied using SRIM Monte Carlo code for anthracene for different heavy ions of 100 keV kinetic energy. It has been observed that the variation in Zeff becomes less when the atomic number of the ions increase. Glass-Pb, bronze, brass, stainless-steel and Freon gas were found to vary less than 10% in the energy region 10 keV to 10 MeV. For total proton interaction, discrepancies up to 10% and 18% between two databases namely PSTAR and SRIM were noted in mass stopping power and Zeff of water, respectively. The range calculations resulted with a conclusion that the metal alloys and glass-Pb have lowest values of ranges confirming best shielding against energetic heavy ions whereas freon and P 10 gases have the highest values of ranges in the entire energy region. The simulation results showed that the energy loss (%) to target electrons decreases as the Z of the incident ion increases. Also, it was observed that the radiation damage first increases with Z of the ion and then keeps almost constant for ions with Z≥52.

  3. Mass attenuation coefficient (μ/ρ), effective atomic number (Z{sub eff}) and measurement of x-ray energy spectra using based calcium phosphate biomaterials: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Z, M. A.; Da Silva, T. A.; Nogueira, M. S. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Pte. Antonio Carlos 6627, Belo Horizonte 31270-901, Minas Gerais (Brazil); Goncalves Z, E., E-mail: madelon@cdtn.br [Pontifice Catholic University of Minas Gerais, Av. Dom Jose Gaspar 500, Belo Horizonte 30535-901, Minas Gerais (Brazil)

    2015-10-15

    In dentistry, alveolar bone regeneration procedures using based calcium phosphate biomaterials have been shown effective. However,there are not reports in the literature of studies the interaction of low energy radiation in these biomaterials used as attenuator and not being then allowed a comparison between the theoretical values and experimental.The objective of this study was to determine the interaction of radiation parameters of four dental biomaterials - BioOss, Cerasorb M Dental, Straumann Boneceramic and Osteogen for diagnostic radiology qualities. As a material and methods, the composition of the biomaterials was determined by the analytical techniques. The samples with 0.181 cm to 0,297 cm thickness were experimentally used as attenuators for the measurement of the transmitted X-rays spectra in X-ray equipment with 50 to 90 kV range by spectrometric system comprising the Cd Te detector. After this procedure, the mass attenuation coefficient, the effective atomic number were determined and compared between all the specimens analyzed, using the program WinXCOM in the range of 10 to 200 keV. In all strains examined observed that the energy spectrum of x-rays transmitted through the BioOss has the mean energy slightly smaller than the others biomaterials for close thickness. The μ/ρ and Z{sub eff} of the biomaterials showed its dependence on photon energy and atomic number of the elements of the material analyzed. It is concluded according to the methodology employed in this study that the measurements of x-ray spectrum, μ/ρ and Z{sub eff} using biomaterials as attenuators confirmed that the thickness, density, composition of the samples, the incident photon energy are factors that determine the characteristics of radiation in a tissue or equivalent material. (Author)

  4. Atomic energy

    CERN Multimedia

    1996-01-01

    Interviews following the 1991 co-operation Agreement between the Department of Atomic Energy (DAE) of the Government of India and the European Organization for Nuclear Research (CERN) concerning the participation in the Large Hadron Collider Project (LHC) . With Chidambaram, R, Chairman, Atomic Energy Commission and Secretary, Department of Atomic Energy, Department of Atomic Energy (DAE) of the Government of India and Professor Llewellyn-Smith, Christopher H, Director-General, CERN.

  5. Atom chips

    CERN Document Server

    Reichel, Jakob

    2010-01-01

    This book provides a stimulating and multifaceted picture of a rapidly developing field. The first part reviews fundamentals of atom chip research in tutorial style, while subsequent parts focus on the topics of atom-surface interaction, coherence on atom chips, and possible future directions of atom chip research. The articles are written by leading researchers in the field in their characteristic and individual styles.

  6. Small angle scattering of 59.54 keV photons by elemental samples in the atomic number region 13 ≤ Z ≤ 82

    Directory of Open Access Journals (Sweden)

    L. Vinaykumar

    2016-01-01

    Full Text Available In the present paper, we report the angle integrated coherent scattering cross sections of some elements at low momentum transfer over four angular ranges for some elements in the atomic number range 13≤Z≤82 for 241Am (59.54 keV gamma rays. The coherent scattering cross sections were derived from the experimentally measured total (Coherent + incoherent scattering cross sections for the elements at the energy of interest by subtracting separately the small contribution of the corresponding angle integrated incoherent scattering cross sections. The theoretical angle integrated incoherent scattering cross sections were computed by numerically integrating the values provided in the compilations based on the non-relativistic Hartree-Fock (NRHF model and the modified form factor (MFF model for the charge distribution within the atom. The present values of the angle integrated coherent scattering cross sections of the elements Al, Fe, Cu, Zn, Cd, Sn and Pb at 59.54 keV in the angular ranges of (0∘−4∘, (0∘−6∘, (0∘−8∘ and (0°–10° so obtained are compared with the corresponding theoretical S-matrix data within the range of experimental errors. The root mean square error on the measured cross sections was found to be the lowest for Al at 4.1% and the highest for Pb at 4.9%. For the other elements the error was in between these two values. Possible conclusions are drawn based on the present study.

  7. 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...

  8. Preparation and Performance of Wave Absorbing Materials by Metallization of Nocadia%以诺卡氏菌为模板的微纳米Ni-Fe-P吸波材料的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    韩宇; 李松梅; 刘建华; 于美

    2011-01-01

    采用化学镀技术在经过敏活处理的诺卡氏菌表面制备微纳米Ni-Fe-P吸波材料.通过SEM(扫描电子显微镜),EDS(能谱仪),XRD(X射线衍射),VSM(振动样品强磁计)对材料形貌、成分、结构及磁性能进行了分析,并探讨了菌体化学镀前处理机理以及装载量对镀层质量、镀液利用率以及磁性能的影响.结果表明:采用敏活一步法可使菌体表面具备化学沉积的条件.随着诺卡氏菌装载量的提高,诺卡氏菌表面镀层粗糙化、球形颗粒增多且分解产物增多,当装载量为80 mL时,镀层的质量以及镀液的利用率最好.装载量的变化对镀层成分的影响不大,当装载量为80 mL时,镀层中Ni,Fe,P的质量分数分别为83.17%,6.12%,10.71%;装载量的变化对镀层的磁性能影响不大且镀层为典型的非晶态结构.采用矢量网络分析仪(VNA)对镀层的电磁参数进行了测量,结果表明:镀层在10~12,15~17 GHz频段具有较好的吸波性能,当吸收剂厚度为2 mm时,反射损耗可达27 dB.%Micro/nano Ni-Fe-P wave absorbing materials were prepared on the surface of Nocadia pretreated by electroless plating technique.The morphology, component, structure and magnetic property were characterized by SEM (scanning electron microscope), EDS (energy dispersive spectrometer), XRD (X-ray diffraction) and VSM (vibrating sample magnetometer).The results clearly demonstrated that one-step method was in a condition to deposit on the surface of Nocadia, and the surface of plating was roughed with the increase of the spherical particles and decomposition products due to the effects of the load, the quality of plating and the utilization of electroless solution were the best when the load was 80 mL.The average contents of Ni, Fe and P element of the metal layer with 80 mL load (w) were about 83.17%, 6.12% and 10.71%, respectively.The magnetic property was changed little by increasing of the load, and the plating was amorphous

  9. Maximally Atomic Languages

    Directory of Open Access Journals (Sweden)

    Janusz Brzozowski

    2014-05-01

    Full Text Available The atoms of a regular language are non-empty intersections of complemented and uncomplemented quotients of the language. Tight upper bounds on the number of atoms of a language and on the quotient complexities of atoms are known. We introduce a new class of regular languages, called the maximally atomic languages, consisting of all languages meeting these bounds. We prove the following result: If L is a regular language of quotient complexity n and G is the subgroup of permutations in the transition semigroup T of the minimal DFA of L, then L is maximally atomic if and only if G is transitive on k-subsets of 1,...,n for 0 <= k <= n and T contains a transformation of rank n-1.

  10. 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...

  11. Optimized absorption imaging of mesoscopic atomic clouds

    Science.gov (United States)

    Muessel, Wolfgang; Strobel, Helmut; Joos, Maxime; Nicklas, Eike; Stroescu, Ion; Tomkovič, Jiří; Hume, David B.; Oberthaler, Markus K.

    2013-10-01

    We report on the optimization of high-intensity absorption imaging for small Bose-Einstein condensates. The imaging calibration exploits the linear scaling of the quantum projection noise with the mean number of atoms for a coherent spin state. After optimization for atomic clouds containing up to 300 atoms, we find an atom number resolution of atoms, mainly limited by photon shot noise and radiation pressure.

  12. Importance of the effective atomic number (Z{sub eff}) of TL materials for radiation dosimetry in clinical applications; Importancia del numero atomico efectivo (Z{sub eff}) de materiales TL para dosimetria de la radiacion en aplicaciones clinicas

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez M, P.R. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: pgm@nuclear.inin.mx

    2008-07-01

    The electric power generation, it has been one of the radiation applications of bigger weight, mainly in developed countries. Another sector of more impact is without a doubt that of the medicine. However, for a sure operation with radiations, those international organisms of radiological safety, exist every time more precise detection systems. The thermoluminescent dosimetry is one of the more reliable methods for this purpose, for that several groups of investigators from different parts of the world, they have guided its investigations in the development of new TL materials. However, to avoid underestimate or overestimation of the measured dose with the use of these materials, it should take into account it effective atomic number (Z{sub eff}) it is well known that some TL materials considered as equivalent to the tissue, presents smaller TL intensity when being irradiated with low energy photons, while the TL material known as not equivalent to the tissue, they present the supra sensitivity effect for this radiation type. Nowadays, the estimate of the Z{sub eff} has not been clear, in this work the Z{sub eff} is determined by means of the traditional methods and an own method is presented for its determination. The results of the TL signal of different materials, when being irradiated with photons of effective energy between 24 keV and 1.25 MeV and their relationship with their calculated Z{sub eff} are also presented. (Author)

  13. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    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.

  14. 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...

  15. Effect of dietary fats with odd or even numbers of carbon atoms on metabolic response and muscle damage with exercise in Quarter Horse-type horses with type 1 polysaccharide storage myopathy.

    Science.gov (United States)

    Borgia, Lisa A; Valberg, Stephanie J; McCue, Molly E; Pagan, Joe D; Roe, Charles R

    2010-03-01

    To evaluate effects of fats with odd and even numbers of carbon atoms on muscle metabolism in exercising horses with polysaccharide storage myopathy (PSSM). 8 horses with PSSM (6 females and 2 males; mean +/- SD age, 6.3 +/- 3.9 years). Isocaloric diets (grain, triheptanoin, corn oil, and high-fat, low-starch [HFLS] feed) were fed for 3 weeks each; horses performed daily treadmill exercise. Grain was fed to establish an exercise target, and HFLS feed was fed as a negative control diet. Daily plasma samples were obtained. For each diet, a 15-minute exercise test was performed, and gluteus medius muscle specimens and blood samples were obtained before and after exercise. Feeding triheptanoin, compared with the corn oil diet, resulted in exercise intolerance; higher plasma creatine kinase (CK) activity and concentrations of C3:0- and C7:0-acylcarnitine and insulin; and lower concentrations of nonesterified fatty acids (NEFA) and C16:0-, C18:1-, and C18:2-acylcarnitine, without changes in concentrations of plasma glucose or resting muscle substrates and metabolites. Feeding grain induced higher CK activity and insulin concentrations and lower NEFA concentrations than did corn oil or HFLS feed. Feeding grain induced higher glucose concentrations than did triheptanoin and corn oil. In muscle, feeding grain resulted in lower glucose-6-phosphate, higher citrate, and higher postexercise lactate concentrations than did the other diets. Triheptanoin had detrimental effects, reflecting decreased availability of NEFA, increased insulin stimulation of glycogen synthesis, and potential inhibition of lipid oxidation. Long-chain fats are the best dietetic for PSSM.

  16. Kinetic Atom.

    Science.gov (United States)

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  17. Atomic Fock State Preparation Using Rydberg Blockade

    CERN Document Server

    Ebert, Matthew; Gibbons, Michael; Zhang, Xianli; Saffman, Mark; Walker, Thad G

    2013-01-01

    We use coherent excitation of 3-16 atom ensembles to demonstrate collective Rabi flopping mediated by Rydberg blockade. Using calibrated atom number measurements, we quantitatively confirm the expected $\\sqrt{N}$ Rabi frequency enhancement to within 4%. The resulting atom number distributions are consistent with essentially perfect blockade. We then use collective Rabi $\\pi$ pulses to produce ${\\cal N}=1,2$ atom number Fock states with fidelities of 62% and 48% respectively. The ${\\cal N}=2$ Fock state shows the collective Rabi frequency enhancement without corruption from atom number fluctuations.

  18. Atomic entanglement and decoherence

    Science.gov (United States)

    Genes, Claudiu

    The generation of entanglement in atomic systems plays a central topic in the fields of quantum information storage and processing. Moreover, a special category of entangled states of multi-atom ensembles, spin squeezed states, have been proven to lead to considerable improvement in the sensitivity of precision measurements compared to systems involving uncorrelated atoms. A treatment of entanglement in open systems is, however, incomplete without a precise description of the process of decoherence which necessarily accompanies it. The theory of entanglement and decoherence are the two main topics of this thesis. Methods are described for the generation of strong correlations in large atomic ensembles using either cavity quantum electrodynamics or measurement outcome conditioned quantum dynamics. Moreover, the description of loss of entanglement resulting from the coupling to a noise reservoir (electromagnetic vacuum) is explored. A spin squeezing parameter is used throughout this thesis as both a measure of entanglement strength and as an indication of the sensitivity improvement above the so-called standard quantum limit (sensitivity obtained with uncorrelated particles) in metrology. The first scheme considered consists of a single mode cavity field interacting with a collection of atoms for which spin squeezing is produced in both resonant and off-resonant regimes. In the resonant case, transfer of squeezing from a field state to the atoms is analyzed, while in the off-resonant regime squeezing is produced via an effective nonlinear interaction (one-axis twisting Hamiltonian). A second, more experimentally realistic case, is one involving the interaction of free space atoms with laser pulses; a projective measurement of a source field originating from atomic fluctuations provides a means of preparing atomic collective states such as spin squeezed and Schrodinger cat states. A new "unravelling" is proposed, that employs the detection of photon number in a single

  19. 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

  20. Traps for neutral radioactive atoms

    CERN Document Server

    Sprouse, G D; Grossman, J S; Orozco, L A; Pearson, M R

    2002-01-01

    We describe several methods for efficiently injecting a small number of radioactive atoms into a laser trap. The characteristics of laser traps that make them desirable for physics experiments are discussed and several different experimental directions are described. We describe recent experiments with the alkali element Fr and point to future directions of the neutral atom trapping program.

  1. Nondestructive characterization of municipal-solid-waste-contaminated surface soil by energy-dispersive X-ray fluorescence and low-Z (atomic number) particle electron probe X-ray microanalysis.

    Science.gov (United States)

    Gupta, Dhrubajyoti; Ghosh, Rita; Mitra, Ajoy K; Roy, Subinit; Sarkar, Manoranjan; Chowdhury, Subhajit; Bhowmik, Asit; Mukhopadhyay, Ujjal; Maskey, Shila; Ro, Chul-Un

    2011-11-01

    The long-term environmental impact of municipal solid waste (MSW) landfilling is still under investigation due to the lack of detailed characterization studies. A MSW landfill site, popularly known as Dhapa, in the eastern fringe of the metropolis of Kolkata, India, is the subject of present study. A vast area of Dhapa, adjoining the current core MSW dump site and evolving from the raw MSW dumping in the past, is presently used for the cultivation of vegetables. The inorganic chemical characteristics of the MSW-contaminated Dhapa surface soil (covering a 2-km stretch of the area) along with a natural composite (geogenic) soil sample (from a small countryside farm), for comparison, were investigated using two complementary nondestructive analytical techniques, energy-dispersive X-ray fluorescence (EDXRF) for bulk analysis and low-Z (atomic number) particle electron probe X-ray microanalysis (low-Z particle EPMA) for single-particle analysis. The bulk concentrations of K, Rb, and Zr remain almost unchanged in all the soil samples. The Dhapa soil is found to be polluted with heavy metals such as Cu, Zn, and Pb (highly elevated) and Ti, Cr, Mn, Fe, Ni, and Sr (moderately elevated), compared to the natural countryside soil. These high bulk concentration levels of heavy metals were compared with the Ecological Soil Screening Levels for these elements (U.S. Environment Protection Agency) to assess the potential risk on the immediate biotic environment. Low-Z particle EPMA results showed that the aluminosilicate-containing particles were the most abundant, followed by SiO2, CaCO3-containing, and carbonaceous particles in the Dhapa samples, whereas in the countryside sample only aluminosilicate-containing and SiO2 particles were observed. The mineral particles encountered in the countryside sample are solely of geogenic origin, whereas those from the Dhapa samples seem to have evolved from a mixture of raw dumped MSW, urban dust, and other contributing factors such as wind

  2. Atomic Data: Division B / Commission 14 / Working Group Atomic Data

    CERN Document Server

    Nave, Gillian; Zhao, Gang

    2015-01-01

    This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text. Comprehensive lists of references for atomic spectra can be found in the NIST Atomic Spectra Bibliographic Databases http://physics.nist.gov/asbib.

  3. 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

  4. Korean atomic bomb victims.

    Science.gov (United States)

    Sasamoto, Yukuo

    2009-01-01

    After colonizing Korea, Japan invaded China, and subsequently initiated the Pacific War against the United States, Britain, and their allies. Towards the end of the war, U.S. warplanes dropped atomic bombs on Hiroshima and Nagasaki, which resulted in a large number of Koreans who lived in Hiroshima and Nagasaki suffering from the effects of the bombs. The objective of this paper is to examine the history of Korea atomic bomb victims who were caught in between the U.S., Japan, the Republic of Korea (South Korea) and the Democratic People's Republic of Korea (North Korea).

  5. Similarity of atoms in molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cioslowski, J.; Nanayakkara, A. (Florida State Univ., Tallahassee, FL (United States))

    1993-12-01

    Similarity of atoms in molecules is quantitatively assessed with a measure that employs electron densities within respective atomic basins. This atomic similarity measure does not rely on arbitrary assumptions concerning basis functions or 'atomic orbitals', is relatively inexpensive to compute, and has straightforward interpretation. Inspection of similarities between pairs of carbon, hydrogen, and fluorine atoms in the CH[sub 4], CH[sub 3]F, CH[sub 2]F[sub 2], CHF[sub 3], CF[sub 4], C[sub 2]H[sub 2], C[sub 2]H[sub 4], and C[sub 2]H[sub 6] molecules, calculated at the MP2/6-311G[sup **] level of theory, reveals that the atomic similarity is greatly reduced by a change in the number or the character of ligands (i.e. the atoms with nuclei linked through bond paths to the nucleus of the atom in question). On the other hand, atoms with formally identical (i.e. having the same nuclei and numbers of ligands) ligands resemble each other to a large degree, with the similarity indices greater than 0.95 for hydrogens and 0.99 for non-hydrogens. 19 refs., 6 tabs.

  6. United States History Simulations, 1925-1964: The Scopes Trial, Dropping the Atomic Bomb on Japan, United States versus Alger Hiss, Mississippi--Summer 1964. ETC Simulations Number Three.

    Science.gov (United States)

    Hostrop, Richard W.

    This booklet provides instructions for simulation and role play of historical events in U.S. history from 1925-1964. Included for student research and participation are: the Scopes trial in Tennessee involving supporters of the teaching of evolution in the schools and of creationism; the decision to drop the atomic bomb on Japan ending World War…

  7. Benchmarking Attosecond Physics with Atomic Hydrogen

    Science.gov (United States)

    2015-05-25

    Final 3. DATES COVERED (From - To) 12 Mar 12 – 11 Mar 15 4. TITLE AND SUBTITLE Benchmarking attosecond physics with atomic hydrogen 5a...AND SUBTITLE Benchmarking attosecond physics with atomic hydrogen 5a. CONTRACT NUMBER FA2386-12-1-4025 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...attosecond physics with atomic hydrogen ” May 25, 2015 PI information: David Kielpinski, dave.kielpinski@gmail.com Griffith University Centre

  8. Electron correlation energies in atoms

    Science.gov (United States)

    McCarthy, Shane Patrick

    This dissertation is a study of electron correlation energies Ec in atoms. (1) Accurate values of E c are computed for isoelectronic sequences of "Coulomb-Hooke" atoms with varying mixtures of Coulombic and Hooke character. (2) Coupled-cluster calculations in carefully designed basis sets are combined with fully converged second-order Moller-Plesset perturbation theory (MP2) computations to obtain fairly accurate, non-relativistic Ec values for the 12 closed-shell atoms from Ar to Rn. The complete basis-set (CBS) limits of MP2 energies are obtained for open-shell atoms by computations in very large basis sets combined with a knowledge of the MP2/CBS limit for the next larger closed-shell atom with the same valence shell structure. Then higher-order correlation corrections are found by coupled-cluster calculations using basis sets that are not quite as large. The method is validated for the open-shell atoms from Al to Cl and then applied to get E c values, probably accurate to 3%, for the 4th-period open-shell atoms: K, Sc-Cu, and Ga-Br. (3) The results show that, contrary to quantum chemical folklore, MP2 overestimates |Ec| for atoms beyond Fe. Spin-component scaling arguments are used to provide a simple explanation for this overestimation. (4) Eleven non-relativistic density functionals, including some of the most widely-used ones, are tested on their ability to predict non-relativistic, electron correlation energies for atoms and their cations. They all lead to relatively poor predictions for the heavier atoms. Several novel, few-parameter, density functionals for the correlation energy are developed heuristically. Four new functionals lead to improved predictions for the 4th-period atoms without unreasonably compromising accuracy for the lighter atoms. (5) Simple models describing the variation of E c with atomic number are developed.

  9. Atomic rivals

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, B.

    1990-01-01

    This book is a memoir of rivalries among the Allies over the bomb, by a participant and observer. Nuclear proliferation began in the uneasy wartime collaboration of the United States, England, Canada, and Free France to produce the atom bomb. Through the changes of history, a young French chemist had a role in almost every act of this international drama. This memoir is based on Goldschmidt's own recollections, interviews with other leading figures, and 3,000 pages of newly declassified documents in Allied archives. From his own start as Marie Curie's lab assistant, Goldschmidt's career was closely intertwined with Frances complicated rise to membership in the nuclear club. As a refugee from the Nazis, he became part of the wartime nuclear energy project in Canada and found himself the only French scientist to work (although briefly) on the American atom bomb project.

  10. Atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, A.E.; Kukla, K.; Cheng, S. [Univ. of Toledo, OH (United States)] [and others

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  11. Some studies of the interaction between N-two level atoms and three level atom

    Directory of Open Access Journals (Sweden)

    D.A.M. Abo-Kahla

    2016-07-01

    Full Text Available In this paper, we present the analytical solution for the model that describes the interaction between a three level atom and two systems of N-two level atoms. The effect of the quantum numbers on the atomic inversion and the purity, for some special cases of the initial states, are investigated. We observe that the atomic inversion and the purity change remarkably by the change of the quantum numbers.

  12. Sagan numbers

    OpenAIRE

    Mendonça, J. Ricardo G.

    2012-01-01

    We define a new class of numbers based on the first occurrence of certain patterns of zeros and ones in the expansion of irracional numbers in a given basis and call them Sagan numbers, since they were first mentioned, in a special case, by the North-american astronomer Carl E. Sagan in his science-fiction novel "Contact." Sagan numbers hold connections with a wealth of mathematical ideas. We describe some properties of the newly defined numbers and indicate directions for further amusement.

  13. Fibonacci numbers

    CERN Document Server

    Vorob'ev, Nikolai Nikolaevich

    2011-01-01

    Fibonacci numbers date back to an 800-year-old problem concerning the number of offspring born in a single year to a pair of rabbits. This book offers the solution and explores the occurrence of Fibonacci numbers in number theory, continued fractions, and geometry. A discussion of the ""golden section"" rectangle, in which the lengths of the sides can be expressed as a ration of two successive Fibonacci numbers, draws upon attempts by ancient and medieval thinkers to base aesthetic and philosophical principles on the beauty of these figures. Recreational readers as well as students and teacher

  14. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    through using mathematical names for the numbers such as one-ten-one for 11 and five-ten-six for 56. The project combines the renaming of numbers with supporting the teaching with the new number names. Our hypothesis is that Danish children have more difficulties learning and working with numbers, because...... the Danish number names are more complicated than in other languages. Keywords: A research project in grade 0 and 1th in a Danish school, Base-10 system, two-digit number names, semiotic, cognitive perspectives....

  15. PubChem atom environments.

    Science.gov (United States)

    Hähnke, Volker D; Bolton, Evan E; Bryant, Stephen H

    2015-01-01

    Atom environments and fragments find wide-spread use in chemical information and cheminformatics. They are the basis of prediction models, an integral part in similarity searching, and employed in structure search techniques. Most of these methods were developed and evaluated on the relatively small sets of chemical structures available at the time. An analysis of fragment distributions representative of most known chemical structures was published in the 1970s using the Chemical Abstracts Service data system. More recently, advances in automated synthesis of chemicals allow millions of chemicals to be synthesized by a single organization. In addition, open chemical databases are readily available containing tens of millions of chemical structures from a multitude of data sources, including chemical vendors, patents, and the scientific literature, making it possible for scientists to readily access most known chemical structures. With this availability of information, one can now address interesting questions, such as: what chemical fragments are known today? How do these fragments compare to earlier studies? How unique are chemical fragments found in chemical structures? For our analysis, after hydrogen suppression, atoms were characterized by atomic number, formal charge, implicit hydrogen count, explicit degree (number of neighbors), valence (bond order sum), and aromaticity. Bonds were differentiated as single, double, triple or aromatic bonds. Atom environments were created in a circular manner focused on a central atom with radii from 0 (atom types) up to 3 (representative of ECFP_6 fragments). In total, combining atom types and atom environments that include up to three spheres of nearest neighbors, our investigation identified 28,462,319 unique fragments in the 46 million structures found in the PubChem Compound database as of January 2013. We could identify several factors inflating the number of environments involving transition metals, with many

  16. Eulerian numbers

    CERN Document Server

    Petersen, T Kyle

    2015-01-01

    This text presents the Eulerian numbers in the context of modern enumerative, algebraic, and geometric combinatorics. The book first studies Eulerian numbers from a purely combinatorial point of view, then embarks on a tour of how these numbers arise in the study of hyperplane arrangements, polytopes, and simplicial complexes. Some topics include a thorough discussion of gamma-nonnegativity and real-rootedness for Eulerian polynomials, as well as the weak order and the shard intersection order of the symmetric group. The book also includes a parallel story of Catalan combinatorics, wherein the Eulerian numbers are replaced with Narayana numbers. Again there is a progression from combinatorics to geometry, including discussion of the associahedron and the lattice of noncrossing partitions. The final chapters discuss how both the Eulerian and Narayana numbers have analogues in any finite Coxeter group, with many of the same enumerative and geometric properties. There are four supplemental chapters throughout, ...

  17. 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.

  18. Atomic Data: Division B / Commission 14 / Working Group Atomic Data

    OpenAIRE

    Nave, Gillian; Nahar, Sultana; Zhao, Gang

    2015-01-01

    This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text. Comprehensive...

  19. Understanding Atomic Structure: Is There a More Direct and Compelling Connection between Atomic Line Spectra and the Quantization of an Atom's Energy?

    Science.gov (United States)

    Rittenhouse, Robert C.

    2015-01-01

    The "atoms first" philosophy, adopted by a growing number of General Chemistry textbook authors, places greater emphasis on atomic structure as a key to a deeper understanding of the field of chemistry. A pivotal concept needed to understand the behavior of atoms is the restriction of an atom's energy to specific allowed values. However,…

  20. Understanding Atomic Structure: Is There a More Direct and Compelling Connection between Atomic Line Spectra and the Quantization of an Atom's Energy?

    Science.gov (United States)

    Rittenhouse, Robert C.

    2015-01-01

    The "atoms first" philosophy, adopted by a growing number of General Chemistry textbook authors, places greater emphasis on atomic structure as a key to a deeper understanding of the field of chemistry. A pivotal concept needed to understand the behavior of atoms is the restriction of an atom's energy to specific allowed values. However,…

  1. Atomic Mass and Nuclear Binding Energy for F-35 (Fluorine)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume A `Nuclei with Z = 1 - 54' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope F-35 (Fluorine, atomic number Z = 9, mass number A = 35).

  2. Quantum Electronics for Atomic Physics

    CERN Document Server

    Nagourney, Warren

    2010-01-01

    Quantum Electronics for Atomic Physics provides a course in quantum electronics for researchers in atomic physics. The book covers the usual topics, such as Gaussian beams, cavities, lasers, nonlinear optics and modulation techniques, but also includes a number of areas not usually found in a textbook on quantum electronics. It includes such practical matters as the enhancement of nonlinear processes in a build-up cavity, impedance matching into a cavity, laser frequencystabilization (including servomechanism theory), astigmatism in ring cavities, and atomic/molecular spectroscopic techniques

  3. Review of atomic mass formula

    Energy Technology Data Exchange (ETDEWEB)

    Tachibana, Takahiro [Waseda Univ., Tokyo (Japan). Advanced Research Center for Science and Engineering

    1997-07-01

    Wapstra and Audi`s Table is famous for evaluation of experimental data of atomic nuclear masses (1993/1995 version) which estimated about 2000 kinds of nuclei. The error of atomic mass of formula is 0.3 MeV-0.8 MeV. Four kinds of atomic mass formula: JM (Jaenecke and Masson), TUYY (Tachibana, Uno, Yamada and Yamada), FRDM (Moeller, Nix, Myers and Swiatecki) and ETFSI (Aboussir, Pearson, Dutta and Tondeur) and their properties (number of parameter and error etc.) were explained. An estimation method of theoretical error of mass formula was presented. It was estimated by the theoretical error of other surrounding nuclei. (S.Y.)

  4. New Developments in Atom Interferometry

    Science.gov (United States)

    1992-07-01

    interferometers can be applied to a number of experiments in fundamental physics: tests of quantum mechanics such as the Aharonov - Casher effect (6), measurement of...qualitatively new types of experiments involving inertial effects , studies of atomic and molecular properties, tests of basic quantum physics, and may ultimately...laser light as the beam splitters. Atom interferometers will make possible qualitatively new types of experiments involving inertial effects , studies of

  5. Magic Numbers

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    THE last digit of my home phone number in Beijing is 4. “So what?” European readers might ask.This was my attitude when I first lived in China; I couldn't understand why Chinese friends were so shocked at my indifference to the number 4. But China brings new discoveries every day, and I have since seen the light. I know now that Chinese people have their own ways of preserving their well being, and that they see avoiding the number 4 as a good way to stay safe.

  6. Number theory

    CERN Document Server

    Andrews, George E

    1994-01-01

    Although mathematics majors are usually conversant with number theory by the time they have completed a course in abstract algebra, other undergraduates, especially those in education and the liberal arts, often need a more basic introduction to the topic.In this book the author solves the problem of maintaining the interest of students at both levels by offering a combinatorial approach to elementary number theory. In studying number theory from such a perspective, mathematics majors are spared repetition and provided with new insights, while other students benefit from the consequent simpl

  7. Atomic magnetometer

    Science.gov (United States)

    Schwindt, Peter [Albuquerque, NM; Johnson, Cort N [Albuquerque, NM

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  8. Detecting Neutral Atoms on an Atom Chip

    OpenAIRE

    Wilzbach, M.; Haase, A.; Schwarz, M; Heine, D.; Wicker, K.; Liu, X; Brenner, K. -H.; Groth, S.; Fernholz, Th.; Hessmo, B.; Schmiedmayer, J.

    2006-01-01

    Detecting single atoms (qubits) is a key requirement for implementing quantum information processing on an atom chip. The detector should ideally be integrated on the chip. Here we present and compare different methods capable of detecting neutral atoms on an atom chip. After a short introduction to fluorescence and absorption detection we discuss cavity enhanced detection of single atoms. In particular we concentrate on optical fiber based detectors such as fiber cavities and tapered fiber d...

  9. Nice numbers

    CERN Document Server

    Barnes, John

    2016-01-01

    In this intriguing book, John Barnes takes us on a journey through aspects of numbers much as he took us on a geometrical journey in Gems of Geometry. Similarly originating from a series of lectures for adult students at Reading and Oxford University, this book touches a variety of amusing and fascinating topics regarding numbers and their uses both ancient and modern. The author intrigues and challenges his audience with both fundamental number topics such as prime numbers and cryptography, and themes of daily needs and pleasures such as counting one's assets, keeping track of time, and enjoying music. Puzzles and exercises at the end of each lecture offer additional inspiration, and numerous illustrations accompany the reader. Furthermore, a number of appendices provides in-depth insights into diverse topics such as Pascal’s triangle, the Rubik cube, Mersenne’s curious keyboards, and many others. A theme running through is the thought of what is our favourite number. Written in an engaging and witty sty...

  10. Estudio de la acción del probiótico Sorbial en los indicadores nutricionales de hollejos de naranja conservados con diferentes materiales absorbentes Study of the action of the Sorbial probiotic on the nutritional indicators of orange pulp conserved with different absorbing materials

    Directory of Open Access Journals (Sweden)

    F Ojeda

    2008-09-01

    Full Text Available Con el objetivo de evaluar el efecto que ejerce el probiótico Sorbial en el valor nutritivo de los ensilajes de hollejo de cítrico conservados con materiales absorbentes, se desarrolló una investigación con ovinos, consis­tente en evaluar primero el ensilaje y a continuación el mismo tratamiento, con probiótico Sorbial (20 g de probiótico/animal/día. Los tratamientos fueron: a hollejo de naranja (HN; b HN + 10% de bagacillo de caña de azúcar; c HN + 20% de morera premarchitada (40% MS; y d HN + 10% de paja de frijol. En los ensilajes se determinó la MS, la MO, la PB, la FB, el pH y el N-NH3/Nt (%. Para garantizar las necesidades de mantenimiento de los animales en proteína bruta, se suministró 1 kg de morera fresca; mientras que los ensilajes se ofrecieron a voluntad. El valor nutritivo se determinó a través del consumo y de los porcentajes de digestibilidad de la MO, la PB y la FB. La materia seca y la fibra bruta se incrementaron con la incorporación de los materiales absorbentes. La evaluación integral de los tratamientos indicó que el suministro del probiótico aumentó el consumo de la ración en 5 g MS/kg P0.75, así como la ingestión de MO (+ 5,6 g, PB (+ 0,8 g y FB digestible (+ 3,1 g. Se concluye que el uso del probiótico en dietas de ensilajes mixtos de hollejos de naranja mejora los indicadores nutricionales y que las respuestas zootécnicas dependen del material absorbente empleado.With the objective of evaluating the effect exerted by the Sorbial probiotic on the nutritive value of citrus pulp silages conserved with different absorbing materials, a study was carried out with sheep consisting in evaluating first the silage under study and afterwards the same treatment, with Sorbial probiotic (20 g probiotic/animal/ day. The treatments were: a orange pulp (OP; b OP + 10% sugarcane bagasse; c OP + 20% pre-wilted mulberry (40% DM; and d OP + 10% bean straw. In the silages dry matter, organic matter, crude protein

  11. Entanglement properties between two atoms in the binomial optical field interacting with two entangled atoms

    Institute of Scientific and Technical Information of China (English)

    刘堂昆; 张康隆; 陶宇; 单传家; 刘继兵

    2016-01-01

    The temporal evolution of the degree of entanglement between two atoms in a system of the binomial optical field interacting with two arbitrary entangled atoms is investigated. The influence of the strength of the dipole–dipole interaction between two atoms, probabilities of the Bernoulli trial, and particle number of the binomial optical field on the temporal evolution of the atomic entanglement are discussed. The result shows that the two atoms are always in the entanglement state. Moreover, if and only if the two atoms are initially in the maximally entangled state, the entanglement evolution is not affected by the parameters, and the degree of entanglement is always kept as 1.

  12. Transcendental numbers

    CERN Document Server

    Murty, M Ram

    2014-01-01

    This book provides an introduction to the topic of transcendental numbers for upper-level undergraduate and graduate students. The text is constructed to support a full course on the subject, including descriptions of both relevant theorems and their applications. While the first part of the book focuses on introducing key concepts, the second part presents more complex material, including applications of Baker’s theorem, Schanuel’s conjecture, and Schneider’s theorem. These later chapters may be of interest to researchers interested in examining the relationship between transcendence and L-functions. Readers of this text should possess basic knowledge of complex analysis and elementary algebraic number theory.

  13. Dynamical Properties of Scaled Atomic Wehrl Entropy of Multiphoton JCM in the Presence of Atomic Damping

    Directory of Open Access Journals (Sweden)

    S. Abdel-Khalek

    2013-01-01

    Full Text Available We study the dynamics of the atomic inversion, scaled atomic Wehrl entropy, and marginal atomic Q-function for a single two-level atom interacting with a one-mode cavity field taking in the presence of atomic damping. We obtain the exact solution of the master equation in the interaction picture using specific initial conditions. We examine the effects of atomic damping parameter and number of multiphoton transition on the scaled atomic Wehrl entropy, atomic Q-function, and their marginal distribution. We observe an interesting monotonic relation between the different physical quantities in the case of different values of the number of photon transition during the time evolution.

  14. Sub-atom shot noise Faraday imaging of ultracold atom clouds

    CERN Document Server

    Kristensen, Mick A; Pedersen, Poul L; Klempt, Carsten; Sherson, Jacob F; Arlt, Jan J; Hilliard, Andrew J

    2016-01-01

    We demonstrate that a dispersive imaging technique based on the Faraday effect can measure the atom number in a large, ultracold atom cloud with a precision below the atom shot noise level. The minimally destructive character of the technique allows us to take multiple images of the same cloud, which enables sub-atom shot noise measurement precision of the atom number and allows for an in situ determination of the measurement precision. We have developed a noise model that quantitatively describes the noise contributions due to photon shot noise in the detected light and the noise associated with single atom loss. This model contains no free parameters and is calculated through an analysis of the fluctuations in the acquired images. For clouds containing $N \\sim 5 \\times 10^6$ atoms, we achieve a precision more than a factor of two below the atom shot noise level.

  15. Sub-atom shot noise Faraday imaging of ultracold atom clouds

    Science.gov (United States)

    Kristensen, M. A.; Gajdacz, M.; Pedersen, P. L.; Klempt, C.; Sherson, J. F.; Arlt, J. J.; Hilliard, A. J.

    2017-02-01

    We demonstrate that a dispersive imaging technique based on the Faraday effect can measure the atom number in a large, ultracold atom cloud with a precision below the atom shot noise level. The minimally destructive character of the technique allows us to take multiple images of the same cloud, which enables sub-atom shot noise measurement precision of the atom number and allows for an in situ determination of the measurement precision. We have developed a noise model that quantitatively describes the noise contributions due to photon shot noise in the detected light and the noise associated with single atom loss. This model contains no free parameters and is calculated through an analysis of the fluctuations in the acquired images. For clouds containing N∼ 5× {10}6 atoms, we achieve a precision more than a factor of two below the atom shot noise level.

  16. The entanglement evolution between two entangled atoms

    Indian Academy of Sciences (India)

    Zong-Cheng Xu; Mai-Lin Liang; Ya-Ting Zhang; Jian-Quan Yao

    2016-03-01

    The entanglement properties of two entangled atoms interacting with the field under intensity-dependent coupling are studied in detail. It is found that the degree of entanglement between the two atoms changes periodically and undergoes the entanglement sudden death (ESD) and sudden birth at some time. The entanglement properties between the field and the atom insidethe cavity are dependent on the photon number. Most interestingly, the entanglement between the field and the atom in the field is influenced significantly by manipulating the atom outside the field.

  17. Electronic structure of atoms: atomic spectroscopy information system

    Science.gov (United States)

    Kazakov, V. V.; Kazakov, V. G.; Kovalev, V. S.; Meshkov, O. I.; Yatsenko, A. S.

    2017-10-01

    The article presents a Russian atomic spectroscopy, information system electronic structure of atoms (IS ESA) (http://grotrian.nsu.ru), and describes its main features and options to support research and training. The database contains over 234 000 records, great attention paid to experimental data and uniform filling of the database for all atomic numbers Z, including classified levels and transitions of rare earth and transuranic elements and their ions. Original means of visualization of scientific data in the form of spectrograms and Grotrian diagrams have been proposed. Presentation of spectral data in the form of interactive color charts facilitates understanding and analysis of properties of atomic systems. The use of the spectral data of the IS ESA together with its functionality is effective for solving various scientific problems and training of specialists.

  18. Numbers, Please!

    Science.gov (United States)

    Thelin, John R.

    2013-01-01

    What topic would you choose if you had the luxury of writing forever? In this article, John Thelin provides his response: He would opt to write about the history of higher education in a way that relies on quantitative data. "Numbers, please!" is his research request in taking on a longitudinal study of colleges and universities over…

  19. Numbers, Please!

    Science.gov (United States)

    Thelin, John R.

    2013-01-01

    What topic would you choose if you had the luxury of writing forever? In this article, John Thelin provides his response: He would opt to write about the history of higher education in a way that relies on quantitative data. "Numbers, please!" is his research request in taking on a longitudinal study of colleges and universities over…

  20. Negative Numbers

    Science.gov (United States)

    Galbraith, Mary J.

    1974-01-01

    Examination of models for representing integers demonstrates that formal operational thought is required for establishing the operations on integers. Advocated is the use of many models for introducing negative numbers but, apart from addition, it is recommended that operations on integers be delayed until the formal operations stage. (JP)

  1. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Majid [Isfahan Nuclear Science and Technology Research Institute (NSTRT), Reactor and Accelerators Research and Development School, Atomic Energy Organization (Iran, Islamic Republic of)], E-mail: m_jalali@entc.org.ir; Mohammadi, Ali [Faculty of Science, Department of Physics, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2008-05-15

    The compounds Na{sub 2}B{sub 4}O{sub 7}, H{sub 3}BO{sub 3}, CdCl{sub 2} and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the {gamma} rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H{sub 3}BO{sub 3} with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  2. Non-self-absorbing materials for Luminescent Solar Concentrators (LSC)

    Science.gov (United States)

    Saraidarov, T.; Levchenko, V.; Grabowska, A.; Borowicz, P.; Reisfeld, R.

    2010-05-01

    The diheptyl-bipyridyl-diol, as a non-self-absorbing fluorescent compound characterized by a large separation between absorption and fluorescence bands, has been incorporated in polyvinyl-butyral film. Steady state luminescence and lifetime were measured. An increase of luminescence intensity by about 34% in the presence of silver nanoparticles was observed. No appreciable changes were found in the corresponding lifetimes. The system is proposed as a potential candidate for increasing the LSC efficiency.

  3. SHOCK-ABSORBING MATERIALS. REPORT 4. AGING OF BACKPACKING MATERIALS.

    Science.gov (United States)

    Seven materials that are currently being considered for use as backpacking around deeply buried protective structures and silos were investigated for...characteristics necessary for a better understanding of a material’s behavior when used as a backpacking were also determined. The materials studied included

  4. Dysprosium titanate as an absorber material for control rods

    Science.gov (United States)

    Risovany, V. D.; Varlashova, E. E.; Suslov, D. N.

    2000-09-01

    Disprosium titanate is an attractive control rod material for the thermal neutron reactors. Its main advantages are: insignificant swelling, no out-gassing under neutron irradiation, rather high neutron efficiency, a high melting point (˜1870°C), non-interaction with the cladding at temperatures above 1000°C, simple fabrication and easily reprocessed non-radioactive waste. It can be used in control rods as pellets and powder. The disprosium titanate control rods have worked off in the MIR reactor for 17 years, in VVER-1000 - for 4 years without any operating problems. After post-irradiation examinations this type of control rod having high lifetime was recommended for the VVER and RBMK. The paper presents the examination results of absorber element dummies containing dysprosium titanate, irradiated in the SM reactor to the neutron fluence of 3.4×10 22 cm -2 ( E>0.1 MeV) and, also, the data on structure, thermal-physical properties of dysprosium titanate, efficiency of dysprosium titanate control rods.

  5. Polypyrrole Stability and Coatings for Radar Absorbing Materials

    Science.gov (United States)

    2004-12-01

    organiques . Dans cet article, on examine la chimie du polypyrrole électro-conducteur et les facteurs relatifs à la préparation de revêtements faits à partir...l’absorbeur. Les absorbeurs faits de matériaux organiques tels que des polymères conducteurs sont légers et présentent des propriétés qu’il est possible de

  6. Hydrogen Absorbing Material in Carbonaceous-Metal Hydride

    Directory of Open Access Journals (Sweden)

    Farid Mulana

    2006-06-01

    Full Text Available One of the most promising materials for storing hydrogen in solid state would be included in metal-carbon composites. In order to obtain nanocrystalline metal particles encapsulated by crystalline or amorphous carbon, mechanosynthesis of zirconium-carbonaceous composites and alkali metal-carbonaceous composites was performed. For zirconium-carbonaceous composites, only zirconium-carbon black composite absorbed more hydrogen than expected for a mere mixture with the same composition. The higher hydrogen capacity on the zirconium-carbon black composite would be due to some specific sites on the carbonaceous material created during the milling. Another effect of the composite formation was stabilization of zirconium, that is, the composites did not ignite in air. On alkali metal-carbonaceous composites, carbon black has superior effect in composite formation compared with graphite in which some cooperative effect was only detected on alkali metal-carbon black composite. The effect of the carbonaceous composite formation was resistance to air and anti-sticking characteristics to balls and the wall of the vial during the ball milling.

  7. Metal Hydrides as hot carrier cell absorber materials

    Science.gov (United States)

    Wang, Pei; Wen, Xiaoming; Shrestha, Santosh; Conibeer, Gavin; Aguey-Zinsou, Kondo-Francois

    2016-09-01

    The hot Carrier Solar Cell (HCSC) allows the photon-induced hot carriers (the carriers with energy larger than the band gap) to be collected before they completely thermalise. The absorber of the HCSC should have a large phononic band gap to supress Klemens Decay, which results in a slow carrier cooling speed. In fact, a large phononic band gap likely exists in a binary compound whose constituent elements have a large mass ratio between each other. Binary hydrides with their overwhelming mass ratio of the constituent elements are important absorber candidates. Study on different types of binary hydrides as potential absorber candidates is presented in this paper. Many binary transition metal hydrides have reported theoretical or experimental phonon dispersion charts which show large phononic band gaps. Among these hydrides, the titanium hydride (TiHX) is outstanding because of its low cost, easy fabrication process and is relatively inert to air and water. A TiHX thin film is fabricated by directly hydrogenating an evaporated titanium thin film. Characterisation shows good crystal quality and the hydrogenation process is believed to be successful. Ultrafast transient absorption (TA) spectroscopy is used to study the electron cooling time of TiHX. The result is very noisy due to the low absorption and transmission of the sample. The evolution of the TA curves has been explained by band to band transition using the calculated band structure of TiH2. Though not reliable due to the high noise, decay time fitting at 700nm and 600nm shows a considerably slow carrier cooling speed of the sample.

  8. Atomic Power

    African Journals Online (AJOL)

    metal foil and allowed the alpha-particles to shoot through the foil. ... number of protons for all the stable isotopes, i.e. all the elements ... in this process, the product of the reaction is always ... existing on this earth, namely uranium, to produce.

  9. Preparation of Entangled Atomic States Through Resonant Atom-Field Interaction

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A scheme is proposed for the generation of two-atom maximally entangled states and multi-atom maximally entangled states of W class. The scheme is based on the simultaneous resonant interaction of atoms with a single-mode cavity field. It does not require accurate adjustment of the interaction time. The time needed to complete the generation does not increase with the number of the atom.

  10. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  11. 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.

  12. Quantum information with Rydberg atoms

    DEFF Research Database (Denmark)

    Saffman, Mark; Walker, T.G.; Mølmer, Klaus

    2010-01-01

    qubits. The availability of a strong long-range interaction that can be coherently turned on and off is an enabling resource for a wide range of quantum information tasks stretching far beyond the original gate proposal. Rydberg enabled capabilities include long-range two-qubit gates, collective encoding...... of multiqubit registers, implementation of robust light-atom quantum interfaces, and the potential for simulating quantum many-body physics. The advances of the last decade are reviewed, covering both theoretical and experimental aspects of Rydberg-mediated quantum information processing.......Rydberg atoms with principal quantum number n»1 have exaggerated atomic properties including dipole-dipole interactions that scale as n4 and radiative lifetimes that scale as n3. It was proposed a decade ago to take advantage of these properties to implement quantum gates between neutral atom...

  13. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    This paper concerns the results from the first year of a three-year research project involving the relationship between Danish number names and their corresponding digits in the canonical base 10 system. The project aims to develop a system to help the students’ understanding of the base 10 syste...

  14. Atomic phase diagram

    Institute of Scientific and Technical Information of China (English)

    LI Shichun

    2004-01-01

    Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.

  15. Development of an atomic gravimeter based on atom interferometer

    Science.gov (United States)

    Kwon, Taeg Yong; Lee, Sang-Bum; Park, Sang Eon; Heo, Myoung-Sun; Hong, Hyun-Gue; Park, Chang Yong; Lee, Won-Kyu; Yu, Dai-Hyuk

    2015-05-01

    We present an atomic gravimeter under development at KRISS in Korea for precise measurement of absolute gravity. It is based on atomic interference of laser cooled 87Rb atoms in free fall. The temperature of the atoms is cooled to about 5 μK in a magneto-optic trap. Three Raman light pulses are applied for splitting, reflecting and recombining the atoms clouds while the atoms are in free fall. The pulse width and spacing time of Raman pulses is 40 μs and about 50 ms, respectively. During the interferometry, the frequency difference between the two counter-propagating Raman beams is chirped to compensate for Doppler shift induced by gravitational acceleration. The interference signals are measured at different spacing times to find the chirping rate at which the phase of interference fringe is independent of the spacing time. The chirping rate (~ 25.1 MHz/s) corresponds to g .keff/2 π, where keff = k1 +k2 (k1 and k2 are wave numbers for two Raman beams). At present, we are going to introduce an anti-vibration platform and a magnetic shield for accuracy evaluation of the gravimeter. In the presentation, the preliminary results of the KRISS gravimeter will be discussed.

  16. Decision maker based on atomic switches

    OpenAIRE

    Song-Ju Kim; Tohru Tsuruoka; Tsuyoshi Hasegawa; Masashi Aono; Kazuya Terabe; Masakazu Aono

    2016-01-01

    We propose a simple model for an atomic switch-based decision maker (ASDM), and show that, as long as its total number of metal atoms is conserved when coupled with suitable operations, an atomic switch system provides a sophisticated ``decision-making'' capability that is known to be one of the most important intellectual abilities in human beings. We considered a popular decision-making problem studied in the context of reinforcement learning, the multi-armed bandit problem (MAB); the probl...

  17. Cold Matter Assembled Atom-by-Atom

    CERN Document Server

    Endres, Manuel; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D

    2016-01-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  18. Spectroscopy, Understanding the Atom Series.

    Science.gov (United States)

    Hellman, Hal

    This booklet is one of the "Understanding the Atom" Series. The science of spectroscopy is presented by a number of topics dealing with (1) the uses of spectroscopy, (2) its origin and background, (3) the basic optical systems of spectroscopes, spectrometers, and spectrophotometers, (4) the characteristics of wave motion, (5) the…

  19. Complex Geometry of Nuclei and Atoms

    CERN Document Server

    Atiyah, M F

    2016-01-01

    We propose a new geometrical model of matter, in which neutral atoms are modelled by compact, complex algebraic surfaces. Proton and neutron numbers are determined by a surface's Chern numbers. Equivalently, they are determined by combinations of the Hodge numbers, or the Betti numbers. Geometrical constraints on algebraic surfaces allow just a finite range of neutron numbers for a given proton number. This range encompasses the known isotopes.

  20. Efficient transfer of francium atoms

    Science.gov (United States)

    Aubin, Seth; Behr, John; Gorelov, Alexander; Pearson, Matt; Tandecki, Michael; Collister, Robert; Gwinner, Gerald; Shiells, Kyle; Gomez, Eduardo; Orozco, Luis; Zhang, Jiehang; Zhao, Yanting; FrPNC Collaboration

    2016-05-01

    We report on the progress of the FrPNC collaboration towards Parity Non Conservation Measurements (PNC) using francium atoms at the TRIUMF accelerator. We demonstrate efficient transfer (higher than 40%) to the science vacuum chamber where the PNC measurements will be performed. The transfer uses a downward resonant push beam from the high-efficiency capture magneto optical trap (MOT) towards the science chamber where the atoms are recaptured in a second MOT. The transfer is very robust with respect to variations in the parameters (laser power, detuning, alignment, etc.). We accumulate a growing number of atoms at each transfer pulse (limited by the lifetime of the MOT) since the push beam does not eliminate the atoms already trapped in the science MOT. The number of atoms in the science MOT is on track to meet the requirements for competitive PNC measurements when high francium rates (previously demonstrated) are delivered to our apparatus. The catcher/neutralizer for the ion beam has been tested reliably to 100,000 heating/motion cycles. We present initial tests on the direct microwave excitation of the ground hyperfine transition at 45 GHz. Support from NSERC and NRC from Canada, NSF and Fulbright from USA, and CONACYT from Mexico.

  1. Simulations of atomic-scale sliding friction

    DEFF Research Database (Denmark)

    Sørensen, Mads Reinholdt; Jacobsen, Karsten Wedel; Stoltze, Per

    1996-01-01

    Simulation studies of atomic-scale sliding friction have been performed for a number of tip-surface and surface-surface contacts consisting of copper atoms. Both geometrically very simple tip-surface structures and more realistic interface necks formed by simulated annealing have been studied. Ki...

  2. Atomic coherence control on the entanglement of two atoms in two-photon processes

    Institute of Scientific and Technical Information of China (English)

    Hu Yao-Hua; Fang Mao-Fa; Wu Qin

    2007-01-01

    Considering two identical two-level atoms interacting with a single-mode thermal field through two-photon processes, this paper studies the atomic coherence control on the entanglement between two two-level atoms, and finds that the entanglement is greatly enhanced due to the initial atomic coherence. The results show that the entanglement can be manipulated by changing the initial parameters of the system, such as the superposition coefficients and the relative phases of the initial atomic coherent state and the mean photon number of the cavity field.

  3. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  4. Exotic atoms and their electron shell

    Energy Technology Data Exchange (ETDEWEB)

    Simons, L.M.; Abbot, D.; Bach, B.; Bacher, R.; Badertscher, A.; Bluem, P.; DeCecco, P.; Eades, J.; Egger, J.; Elsener, K.; Gotta, D.; Hauser, P.; Heitlinger, K.; Horvath, D.; Kottmann, F.; Morenzoni, E.; Missimer, J.; Reidy, J.J.; Siegel, R.; Taqqu, D.; Viel, D. (Paul Scherrer Inst., Villigen (Switzerland) Coll. of William and Mary, Williamsburg, VA (United States) Kernforschungszentrum Karlsruhe GmbH, Inst. fuer Kernphysik, Karlsruhe (Germany) Inst. fuer Experimentelle Kernphysik, Univ. Karlsruhe (Germany) CERN, Geneva (Switzerland) Forschungszentrum Juelich GmbH, Inst. fuer Kernphysik (Germany) KFKI Research Inst. for Particle and Nuclear Physics, Budapest (Hungary) Univ. Pisa (Italy) INFN - Pisa (Italy) ETH Zuerich, Villigen (Switzerland) Physics Dept., Univ. of Mississippi, University, MS (United States))

    1994-04-01

    Progress in the field of exotic atoms seems to increase proportionally with the number of exotic atoms produced and the increase in energy resolution with which the transition energies are determined. Modern experiments use high resolution crystal spectrometers or even aim at laser spectroscopy. The accuracy of these methods is limited by the interaction of the exotic atoms with their surroundings. The most important source of errors is the energy shift caused by the not well known status of the atomic electron shell. A novel method to eliminate these sources of error is presented and the possibilities for further high precision experiments is outlined. (orig.)

  5. Exotic atoms and their electron shell

    Science.gov (United States)

    Simons, L. M.; Abbot, D.; Bach, B.; Bacher, R.; Badertscher, A.; Blüm, P.; DeCecco, P.; Eades, J.; Egger, J.; Elsener, K.; Gotta, D.; Hauser, P.; Heitlinger, K.; Horváth, D.; Kottmann, F.; Morenzoni, E.; Missimer, J.; Reidy, J. J.; Siegel, R.; Taqqu, D.; Viel, D.

    1994-04-01

    Progress in the field of exotic atoms seems to increase proportionally with the number of exotic atoms produced and the increase in energy resolution with which the transition energies are determined. Modern experiments use high resolution crystal spectrometers or even aim at laser spectroscopy. The accuracy of these methods is limited by the interaction of the exotic atoms with their surroundings. The most important source of errors is the energy shift caused by the not well known status of the atomic electron shell. A novel method to eliminate these sources of error is presented and the possibilities for further high precision experiments is outlined.

  6. Preparation of Ultracold Atom Clouds at the Shot Noise Level

    DEFF Research Database (Denmark)

    Gajdacz, M.; Hilliard, A. J.; Kristensen, Matias Ammitzbøll

    2016-01-01

    We prepare number stabilized ultracold atom clouds through the real-time analysis of nondestructive images and the application of feedback. In our experiments, the atom number N∼10^6 is determined by high precision Faraday imaging with uncertainty ΔN below the shot noise level, i.e., ΔN... on this measurement, feedback is applied to reduce the atom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level....

  7. Preparation of Ultracold Atom Clouds at the Shot Noise Level

    DEFF Research Database (Denmark)

    Gajdacz, M.; Hilliard, A. J.; Kristensen, Matias Ammitzbøll

    2016-01-01

    We prepare number stabilized ultracold atom clouds through the real-time analysis of nondestructive images and the application of feedback. In our experiments, the atom number N∼10^6 is determined by high precision Faraday imaging with uncertainty ΔN below the shot noise level, i.e., ΔN... on this measurement, feedback is applied to reduce the atom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level....

  8. Atom Lithography with a Chromium Atomic Beam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-Tao; LI Tong-Bao

    2006-01-01

    @@ Direct write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on the substrate. We design an experiment setup to fabricate chromium nanolines by depositing an atomic beam of 52 Cr through an off-resonant laser standing wave with the wavelength of 425.55 nm onto a silicon substrate. The resulting nanolines exhibit a period of 215 ± 3 nm with height of 1 nm.

  9. Theoretical Calculation of Absolute Radii of Atoms and Ions. Part 1. The Atomic Radii

    Directory of Open Access Journals (Sweden)

    Raka Biswas

    2002-02-01

    Full Text Available Abstract. A set of theoretical atomic radii corresponding to the principal maximum in the radial distribution function, 4πr2R2 for the outermost orbital has been calculated for the ground state of 103 elements of the periodic table using Slater orbitals. The set of theoretical radii are found to reproduce the periodic law and the Lother Meyer’s atomic volume curve and reproduce the expected vertical and horizontal trend of variation in atomic size in the periodic table. The d-block and f-block contractions are distinct in the calculated sizes. The computed sizes qualitatively correlate with the absolute size dependent properties like ionization potentials and electronegativity of elements. The radii are used to calculate a number of size dependent periodic physical properties of isolated atoms viz., the diamagnetic part of the atomic susceptibility, atomic polarizability and the chemical hardness. The calculated global hardness and atomic polarizability of a number of atoms are found to be close to the available experimental values and the profiles of the physical properties computed in terms of the theoretical atomic radii exhibit their inherent periodicity. A simple method of computing the absolute size of atoms has been explored and a large body of known material has been brought together to reveal how many different properties correlate with atomic size.

  10. Ghost Imaging with Atoms

    CERN Document Server

    Khakimov, R I; Shin, D K; Hodgman, S S; Dall, R G; Baldwin, K G H; Truscott, A G

    2016-01-01

    Ghost imaging is a technique -- first realized in quantum optics -- in which the image emerges from cross-correlation between particles in two separate beams. One beam passes through the object to a bucket (single-pixel) detector, while the second beam's spatial profile is measured by a high resolution (multi-pixel) detector but never interacts with the object. Neither detector can reconstruct the image independently. However, until now ghost imaging has only been demonstrated with photons. Here we report the first realisation of ghost imaging of an object using massive particles. In our experiment, the two beams are formed by correlated pairs of ultracold metastable helium atoms, originating from two colliding Bose-Einstein condensates (BECs) via $s$-wave scattering. We use the higher-order Kapitza-Dirac effect to generate the large number of correlated atom pairs required, enabling the creation of a ghost image with good visibility and sub-millimetre resolution. Future extensions could include ghost interfe...

  11. 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...

  12. 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...

  13. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu

    2017-09-01

    A nano - scale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon - atom interactions . A neutral - atom platf orm based on this microfabrication technology will be pre - aligned , 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.

  14. Cavity QED with many atoms

    CERN Document Server

    Martini, U

    1999-01-01

    We have studied the interaction of an arbitrary number Z of atoms with a quantized damped resonator mode. In order to reduce the dimension of the system we employed a symmetrized density operator description. These density operators are analogous to angular momentum eigenstates which are usually referred to as Dicke states.In this symmetric basis the dimension of the atomic system is only 1/6(Z+1)(Z+2)(Z+3) in contrast to 4 sup Z without symmetrization. We have shown that the symmetry is not broken by spontaneous emission. A simple analytical expression for the matrix elements of the complete Liouville operator with respect to the Dicke states was found. Using these results we are able to study the interaction of the atoms with a resonator mode without any further approximations.

  15. Ultrasonic Atomization Amount for Different Frequencies

    Science.gov (United States)

    Yasuda, Keiji; Honma, Hiroyuki; Xu, Zheng; Asakura, Yoshiyuki; Koda, Shinobu

    2011-07-01

    The mass flow rate of ultrasonic atomization was estimated by measuring the vaporization amount from a bulk liquid with a fountain. The effects of ultrasonic frequency and intensity on the atomization characteristics were investigated when the directivities of the acoustic field from a transducer were almost the same. The sample was distillated water and the ultrasonic frequencies were 0.5, 1.0, and 2.4 MHz. The mass flow rate of ultrasonic atomization increased with increasing ultrasonic intensity and decreasing ultrasonic frequency. The fountain was formed at the liquid surface where the effective value of acoustic pressure was above atmospheric pressure. The fountain height was strongly governed by the acoustic pressure at the liquid surface of the transducer center. At the same ultrasonic intensity, the dependence of ultrasonic frequency on the number of atomized droplets was small. At the same apparent surface area of the fountain, the number of atomized droplets became larger as the ultrasonic frequency increased.

  16. Variational electrodynamics of Atoms

    CERN Document Server

    De Luca, Jayme

    2013-01-01

    We study extrema with velocity discontinuities for the variational electromagnetic two-body problem. Along $C^2$ segments, these broken extrema satisfy the Euler-Lagrange equations of the variational principle, which are neutral differential delay equations with state-dependent deviating arguments. At points where accelerations are not defined and velocities are discontinuous, broken extrema satisfy Weierstrass-Erdmann corner conditions that energies and momenta are continuous. Here we construct periodic broken extrema near the $C^{\\infty}$ two-body circular orbits, using piecewise-defined $C^2$ solutions of the neutral differential delay equations along regular segments and a variational approximation for the boundary-layer segments. Broken periodic extrema with an integer number of corner points bifurcate from a discrete set of circular orbits, with scales defined by the Weierstrass-Erdmann corner conditions. We consider the three cases of hydrogen, muonium and positronium atoms. In each case the broken ext...

  17. Atomic Particle Detection, Understanding the Atom Series.

    Science.gov (United States)

    Hellman, Hal

    This booklet is one of the booklets in the "Understanding the Atom Series" published by the U. S. Atomic Energy Commission for high school science teachers and their students. The instruments used to detect both particles and electromagnetic radiation that emerge from the nucleus are described. The counters reviewed include ionization chambers,…

  18. Ultrafast Imaging of Electronic Motion in Atoms and Molecules

    Science.gov (United States)

    2016-01-12

    AFRL-AFOSR-VA-TR-2016-0045 Ultrafast Imaging of Electronic Motion in Atoms and Molecules Martin Centurion UNIVERSITY OF NEBRSKA Final Report 01/12...Ultrafast Imaging of Electronic Motion in Atoms and Molecules 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-12-1-0149 5c. PROGRAM ELEMENT NUMBER 6...a gaseous target of atoms or molecules . An optical setup was designed and constructed to compensate for the blurring of the temporal resolution due

  19. Transmission Spectrum of an Optical Cavity Containing N Atoms

    CERN Document Server

    Leslie, S; Brown, K R; Stamper-Kurn, D M; Whaley, K B; Leslie, Sabrina; Shenvi, Neil; Brown, Kenneth R.; Stamper-Kurn, Dan M.

    2003-01-01

    The transmission spectrum of a high-finesse optical cavity containing an arbitrary number of trapped atoms is presented. We take spatial and motional effects into account and show that in the limit of strong coupling, the important spectral features can be determined for an arbitrary number of atoms, N. We also show that these results have important ramifications in limiting our ability to determine the number of atoms in the cavity.

  20. Characterization of grain boundaries in Cu(In,Ga)Se{sub 2} by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Torsten; Cojocaru-Miredin, Oana; Choi, Pyuck-Pa; Raabe, Dierk [Max-Planck Institute for Iron Research GmbH, Duesseldorf (Germany); Wuerz, Roland [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany)

    2012-07-01

    Solar cells based on the compound semiconductor Cu(In,Ga)Se{sub 2} (CIGS) as absorber material exhibit the highest efficiency among all thin-film solar cells. This is surprising high in view of the polycrystalline defect-rich structure of the CIGS absorber films. The high efficiency has been commonly ascribed to the diffusion of alkali metal atoms from the soda-lime glass substrate into the CIGS layer, which can render the grain boundaries (GB) electrically inactive. However, the exact mechanisms of how these impurities enhance the cell efficiency are yet to be clarified. As a step towards a better understanding of CIGS solar cells, we have analyzed the composition of solar-grade CIGS layers at the atomic-scale by using pulsed laser Atom Probe Tomography (APT). To perform APT analyses on selected GBs site-specific sample preparation was carried out using the Focused Ion Beam lift-out technique. In addition, Electron Back Scattered Diffraction was performed to characterize the structure and misorientation of selected GBs. Using APT, segregation of impurities at the GBs was directly observed. APT data of various types of GBs are presented and discussed with respect to the possible effects on the cell efficiency.

  1. High effective atomic number polymer scintillators for gamma ray spectroscopy

    Science.gov (United States)

    Cherepy, Nerine Jane; Sanner, Robert Dean; Payne, Stephen Anthony; Rupert, Benjamin Lee; Sturm, Benjamin Walter

    2014-04-15

    A scintillator material according to one embodiment includes a bismuth-loaded aromatic polymer having an energy resolution at 662 keV of less than about 10%. A scintillator material according to another embodiment includes a bismuth-loaded aromatic polymer having a fluor incorporated therewith and an energy resolution at 662 keV of less than about 10%. Additional systems and methods are also presented.

  2. Presenting the Bohr Atom.

    Science.gov (United States)

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  3. Single Atom Plasmonic Switch

    OpenAIRE

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individ...

  4. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P.; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C.; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  5. Atoms Talking to SQUIDs

    CERN Document Server

    Hoffman, J E; Kim, Z; Wood, A K; Anderson, J R; Dragt, A J; Hafezi, M; Lobb, C J; Orozco, L A; Rolston, S L; Taylor, J M; Vlahacos, C P; Wellstood, F C

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  6. Atomic Storage States

    Institute of Scientific and Technical Information of China (English)

    汪凯戈; 朱诗尧

    2002-01-01

    We present a complete description of atomic storage states which may appear in the electromagnetically induced transparency (EIT). The result shows that the spatial coherence has been included in the atomic collective operators and the atomic storage states. In some limits, a set of multimode atomic storage states has been established in correspondence with the multimode Fock states of the electromagnetic field. This gives a better understanding of the fact that, in BIT, the optical coherent information can be preserved and recovered.

  7. The Nature of Atoms.

    Science.gov (United States)

    Holden, Alan

    This monograph was written for the purpose of presenting physics to college students who are not preparing for careers in physics. It deals with the nature of atoms, and treats the following topics: (1) the atomic hypothesis, (2) the chemical elements, (3) models of an atom, (4) a particle in a one-dimensional well, (5) a particle in a central…

  8. 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.

  9. Defect-free atom arrays on demand

    Science.gov (United States)

    Levine, Harry; Bernien, Hannes; Keesling, Alex; Anschuetz, Eric; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Endres, Manuel; Lukin, Mikhail

    2016-05-01

    Arrays of neutral, trapped atoms have proven to be an extraordinary platform for studying quantum many-body physics and implementing quantum information protocols. Conventional approaches to generate such arrays rely on loading atoms into optical lattices and require elaborate experimental control. An alternative, simpler approach is to load atoms into individual optical tweezers. However, the probabilistic nature of the loading process limits the size of the arrays to small numbers of atoms. Here we present a new method for assembling defect-free arrays of large numbers of atoms. Our technique makes use of an array of tightly focused optical tweezers generated by an acousto-optic deflector. The positions of the traps can be dynamically reconfigured on a sub-millisecond timescale. With single-site resolved fluorescence imaging, we can identify defects in the atom array caused by the probabilistic loading process and rearrange the trap positions in response. This will enable us to generate defect-free atom arrays on demand. We discuss our latest results towards reaching this goal along with schemes to implement long-range interactions between atoms in the array. Now at Caltech.

  10. Few Atom Detection and Manipulation Using Optical Nanofibres

    Science.gov (United States)

    Deasy, Kieran; Watkins, Amy; Morrissey, Michael; Schmidt, Regine; Chormaic, Síle Nic

    We study the coupling of spontaneously emitted photons from laser-cooled 85Rb atoms to the guided modes of an optical nanofibre to demonstrate the potential such fibres offer as tools for detecting and manipulating cold atoms, even when the number of atoms is very small. We also demonstrate the integration of an optical nanofibre into an absorption spectroscopy setup, showcasing the ability of the evanescent field around nanofibres to interact with atoms in close proximity to the fibre. In principle, trapping of single atoms in engineered optical potentials on the surface of the fibre should facilitate entanglement between distant atoms mediated via the guided modes of the nanofibre.

  11. Future population of atomic bomb survivors in Nagasaki.

    Science.gov (United States)

    Yokota, Kenichi; Mine, Mariko; Shibata, Yoshisada

    2013-01-01

    The Nagasaki University Atomic Bomb Survivor Database, which was established in 1978 for elucidating the long-term health effects of the atomic bombing, has registered since 1970 about 120,000 atomic bomb survivors with a history of residence in Nagasaki city. Since the number of atomic bomb survivors has steadily been decreasing, prediction of future population is important for planning future epidemiologic studies, and we tried to predict the population of atomic bomb survivors in Nagasaki city from 2008 to 2030. In addition, we evaluated our estimated population comparing with the actual number from 2008 to 2011.

  12. Atomic Mass and Nuclear Binding Energy for Po-269 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-269 (Polonium, atomic number Z = 84, mass number A = 269).

  13. Atomic Mass and Nuclear Binding Energy for Po-278 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-278 (Polonium, atomic number Z = 84, mass number A = 278).

  14. Atomic Mass and Nuclear Binding Energy for Po-282 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-282 (Polonium, atomic number Z = 84, mass number A = 282).

  15. Atomic Mass and Nuclear Binding Energy for Po-271 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-271 (Polonium, atomic number Z = 84, mass number A = 271).

  16. Atomic Mass and Nuclear Binding Energy for Po-283 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-283 (Polonium, atomic number Z = 84, mass number A = 283).

  17. Atomic Mass and Nuclear Binding Energy for Po-281 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-281 (Polonium, atomic number Z = 84, mass number A = 281).

  18. Atomic Mass and Nuclear Binding Energy for Po-284 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-284 (Polonium, atomic number Z = 84, mass number A = 284).

  19. Atomic Mass and Nuclear Binding Energy for Po-280 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-280 (Polonium, atomic number Z = 84, mass number A = 280).

  20. Atomic Mass and Nuclear Binding Energy for Po-272 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-272 (Polonium, atomic number Z = 84, mass number A = 272).

  1. Atomic Mass and Nuclear Binding Energy for Po-276 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-276 (Polonium, atomic number Z = 84, mass number A = 276).

  2. Atomic Mass and Nuclear Binding Energy for Po-277 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-277 (Polonium, atomic number Z = 84, mass number A = 277).

  3. Atomic Mass and Nuclear Binding Energy for Po-275 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-275 (Polonium, atomic number Z = 84, mass number A = 275).

  4. Atomic Mass and Nuclear Binding Energy for Po-273 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-273 (Polonium, atomic number Z = 84, mass number A = 273).

  5. Atomic Mass and Nuclear Binding Energy for Po-274 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-274 (Polonium, atomic number Z = 84, mass number A = 274).

  6. Atomic Mass and Nuclear Binding Energy for Po-270 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-270 (Polonium, atomic number Z = 84, mass number A = 270).

  7. Atomic Mass and Nuclear Binding Energy for Po-279 (Polonium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Po-279 (Polonium, atomic number Z = 84, mass number A = 279).

  8. Atomic Mass and Nuclear Binding Energy for Ra-226 (Radium)

    Science.gov (United States)

    Sukhoruchkin, S. I.; Soroko, Z. N.

    This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ra-226 (Radium, atomic number Z = 88, mass number A = 226).

  9. Positronium-alkali atom scattering at medium energies

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Ajoy [Laban Hrad Vidyapith, AD-369, Salt Lake City, Kolkata 700 064 (India); Basu, Arindam [Department of Physics, Maheshtala College, Chandannagar, South 24 Parganas, Kolkata 700 140 (India); Sarkar, Nirmal K [Sodepur Chandrachur Vidyapith, 1, Desh Bandhu Nagar, Sodepur, 743 174 (India); Sinha, Prabal K [Department of Physics, Bangabasi College, 19, Raj Kumar Chakravorty Sarani, Kolkata 700 009 (India)

    2004-04-28

    We investigate the scattering of orthopositronium (o-Ps) atom off different atomic alkali targets (Na to Cs) at low and medium energies (up to 120 eV). Projectile-elastic and target-elastic close-coupling models have been employed to investigate the systems in addition to the static-exchange model. Elastic, excitation and total cross sections have been reported for all four systems. The magnitude of the alkali excitation cross section increases with increasing atomic number of the target atom while the position of the peak value shifts towards lower incident energies. The magnitudes of the Ps excitation and ionization cross sections increase steadily with atomic number with no change in the peak position. The reported results show regular behaviour with increasing atomic number of the target atom. Scattering parameters for the Ps-Rb and Ps-Cs systems are being reported for the first time.

  10. Study of diluting and absorber materials to control reactivity during a postulated core melt down accident in Generation IV reactors; Etude des materiaux sacrificiels absorbants et diluants pour le controle de la reactivite dans le cas d'un accidnet hypothetique de fusion du coeur de reacteurs de quatrieme generation

    Energy Technology Data Exchange (ETDEWEB)

    Plevacova, K.

    2010-12-16

    In order to limit the consequences of a hypothetical core meltdown accident in Generation IV Sodium Fast Reactors, absorber materials in or near the core, such as boron carbide B{sub 4}C, and diluting materials in the core catcher will be used to prevent recriticality within the mixture of molten oxide fuel and molten structures called corium. The aim of the PhD thesis was to select materials of both types and to understand their behaviour during their interaction with corium, from chemical and thermodynamic point of view. Concerning B{sub 4}C, thermodynamic calculations and experiments agree with the formation of two immiscible phases at high temperature in the B{sub 4}C - UO{sub 2} system: one oxide and one boride. This separation of phases can reduce the efficiency of the neutrons absorption inside the molten fuel contained in the oxide phase. Moreover, a volatilization of a part of the boron element can occur. According to these results, the necessary quantity of B{sub 4}C to be introduced should be reconsidered for postulated severe accident sequence. Other solution could be the use of Eu{sub 2}O{sub 3} or HfO{sub 2} as absorber material. These oxides form a solid solution with the oxide fuel. Concerning the diluting materials, mixed oxides Al{sub 2}O{sub 3} - HfO{sub 2} and Al{sub 2}O{sub 3} - Eu{sub 2}O{sub 3} were preselected. These systems being completely unknown to date at high temperature in association with UO{sub 2}, first points on the corresponding ternary phase diagrams were researched. Contrary to Al{sub 2}O{sub 3} - Eu{sub 2}O{sub 3} - UO{sub 2} system, the Al{sub 2}O{sub 3} - HfO{sub 2} - UO{sub 2} mixture presents only one eutectic and thus only one solidification path which makes easier forecasting the behaviour of corium in the core catcher. (author) [French] Resume: Afin de limiter les consequences d'un accident grave avec la fusion du coeur dans un reacteur a neutrons rapides de generation IV refroidi au sodium, la recriticite doit

  11. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  12. NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Pascucci, I.; Simon, M. N. [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Edwards, S. [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States); Heyer, M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); Rigliaco, E. [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Hillenbrand, L. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Gorti, U.; Hollenbach, D., E-mail: pascucci@lpl.arizona.edu [SETI Institute, Mountain View, CA 94043 (United States)

    2015-11-20

    We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within the circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions.

  13. Atomic focusing by quantum fields: Entanglement properties

    Energy Technology Data Exchange (ETDEWEB)

    Paz, I.G. da [Departamento de Física, Universidade Federal do Piauí, Campus Ministro Petrônio Portela, CEP 64049-550, Teresina, PI (Brazil); Frazão, H.M. [Universidade Federal do Piauí, Campus Profa. Cinobelina Elvas, CEP 64900-000, Bom Jesus, PI (Brazil); Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Caixa Postal 702, Belo Horizonte, MG 30123-970 (Brazil); Nemes, M.C. [Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Caixa Postal 702, Belo Horizonte, MG 30123-970 (Brazil); Peixoto de Faria, J.G. [Departamento de Física e Matemática, Centro Federal de Educação Tecnológica de Minas Gerais, Av. Amazonas 7675, Belo Horizonte, MG 30510-000 (Brazil)

    2014-04-01

    The coherent manipulation of the atomic matter waves is of great interest both in science and technology. In order to study how an atom optic device alters the coherence of an atomic beam, we consider the quantum lens proposed by Averbukh et al. [1] to show the discrete nature of the electromagnetic field. We extend the analysis of this quantum lens to the study of another essentially quantum property present in the focusing process, i.e., the atom–field entanglement, and show how the initial atomic coherence and purity are affected by the entanglement. The dynamics of this process is obtained in closed form. We calculate the beam quality factor and the trace of the square of the reduced density matrix as a function of the average photon number in order to analyze the coherence and purity of the atomic beam during the focusing process.

  14. Magneto-Optical Trap for Thulium Atoms

    CERN Document Server

    Sukachev, D; Chebakov, K; Akimov, A; Kanorsky, S; Kolachevsky, N; Sorokin, V

    2010-01-01

    Thulium atoms are trapped in a magneto-optical trap using a strong transition at 410 nm with a small branching ratio. We trap up to $7\\times10^{4}$ atoms at a temperature of 0.8(2) mK after deceleration in a 40 cm long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the MOT which varies between 0.3 -1.5 s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be 22(6) s$^{-1}$. The repumping laser transferring the atomic population out of the F=3 hyperfine ground-state sublevel gives a 30% increase for the lifetime and the number of atoms in the trap.

  15. Long range intermolecular forces in triatomic systems: connecting the atom-diatom and atom-atom-atom representations

    OpenAIRE

    2005-01-01

    The long-range forces that act between three atoms are analysed in both atom-diatom and atom-atom-atom representations. Expressions for atom-diatom dispersion coefficients are obtained in terms of 3-body nonadditive coefficients. The anisotropy of atom-diatom C_6 dispersion coefficients arises primarily from nonadditive triple-dipole and quadruple-dipole forces, while pairwise-additive forces and nonadditive triple-dipole and dipole-dipole-quadrupole forces contribute significantly to atom-di...

  16. Detection of Chern numbers and entanglement in topological multi-component systems through subsystem winding numbers

    NARCIS (Netherlands)

    J. Lisle, de; De, S.; Alba, E.; Bullivant, A.; Garcia-Ripoll, J.J.; Lahtinen, V.; Pachos, J.K.

    2014-01-01

    Topological invariants, such as the Chern number, characterize topological phases of matter. Here we provide a method to detect Chern numbers in systems with two distinct species of fermion, such as spins, orbitals or several atomic states. We analytically show that the Chern number can be

  17. Similarity criterion of flood discharge atomization

    Institute of Scientific and Technical Information of China (English)

    Zhou Hui; Wu Shiqiang; Chen Huiling; Zhou Jie; Wu Xiufeng

    2008-01-01

    By combining the results of prototype observation of flood discharge atomization at the Wujiangdu Hydropower Station, and by adopting the serial model test method, the model scale effect was examined, the influences of the Reynolds and Weber numbers of water flow on the rain intensity of flood discharge atomization were analyzed and a rain intensity conversion relation was established. It is demonstrated that the level of atomization follows the geometric similarity relations and it is possible to ignore the influence of the surface tension of the flow when the Weber number is greater than 500. Despite limitations such as incomplete data sets, it is undoubtedly helpful to study the scale effect of atomization flow, and it is beneficial to identify the rules of the model test results in order to extrapolate to prototype prediction.

  18. Number of Compositions and Convolved Fibonacci numbers

    OpenAIRE

    Janjic, Milan

    2010-01-01

    We consider two type of upper Hessenberg matrices which determinants are Fibonacci numbers. Calculating sums of principal minors of the fixed order of the first type leads us to convolved Fibonacci numbers. Some identities for these and for Fibonacci numbers are proved. We also show that numbers of compositions of a natural number with fixed number of ones appear as coefficients of characteristic polynomial of a Hessenberg matrix which determinant is a Fibonacci number. We derive the explicit...

  19. Dynamics and Thermodynamics of Many Particle Cold Atom Systems

    Science.gov (United States)

    2016-05-05

    AFRL-AFOSR-VA-TR-2016-0219 Dynamics and Thermodynamics of Many Particle Cold Atom Systems Anatoli Polkovnikov TRUSTEES OF BOSTON UNIVERSITY Final...TITLE AND SUBTITLE Dynamics and Thermodynamics of Many Particle Cold Atom Systems 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0039 5c. PROGRAM...FA9550-13-1-0039 “Dynamics and Thermodynamics of Many Particle Cold Atom Systems” by Anatoli Polkovnikov, Professor of Physics Department of Physics

  20. Atoms, molecules and optical physics 1. Atoms and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Ingolf V.; Schulz, Claus-Peter

    2015-09-01

    This is the first volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 1 provides the canonical knowledge in atomic physics together with basics of modern spectroscopy. Starting from the fundamentals of quantum physics, the reader is familiarized in well structured chapters step by step with the most important phenomena, models and measuring techniques. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginners.

  1. New possible properties of atomic nuclei investigated by non linear methods: Fractal and recurrence quantification analysis

    OpenAIRE

    Conte, Elio,; Khrennikov, Andrei Yu.; Zbilut, Joseph P.

    2007-01-01

    For the first time we apply the methodologies of nonlinear analysis to investigate atomic matter. We use these methods in the analysis of Atomic Weights and of Mass Number of atomic nuclei. Using the AutoCorrelation Function and Mutual Information we establish the presence of nonlinear effects in the mechanism of increasing mass of atomic nuclei considered as a function of the atomic number. We find that increasing mass is divergent, possibly chaotic. We also investigate the possible existenc...

  2. Preparation of Ultracold Atom Clouds at the Shot Noise Level.

    Science.gov (United States)

    Gajdacz, M; Hilliard, A J; Kristensen, M A; Pedersen, P L; Klempt, C; Arlt, J J; Sherson, J F

    2016-08-12

    We prepare number stabilized ultracold atom clouds through the real-time analysis of nondestructive images and the application of feedback. In our experiments, the atom number N∼10^{6} is determined by high precision Faraday imaging with uncertainty ΔN below the shot noise level, i.e., ΔNatom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level.

  3. Preparation of ultracold atom clouds at the shot noise level

    CERN Document Server

    Gajdacz, Miroslav; Kristensen, Mick A; Pedersen, Poul L; Klempt, Carsten; Arlt, Jan J; Sherson, Jacob F

    2016-01-01

    We prepare number stabilized ultracold clouds through the real-time analysis of non-destructive images and the application of feedback. In our experiments, the atom number ${N\\sim10^6}$ is determined by high precision Faraday imaging with uncertainty $\\Delta N$ below the shot noise level, i.e., $\\Delta N <\\sqrt{N}$. Based on this measurement, feedback is applied to reduce the atom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level.

  4. Atomic energy levels and Grotrian diagrams

    CERN Document Server

    Bashkin, Stanley

    1975-01-01

    Atomic Energy Levels and Grotrian Diagrams, Volume I: Hydrogen I - Phosphorus XV presents diagrams of various elements that show their energy level and electronic transitions. The book covers the first 15 elements according to their atomic number. The text will be of great use to researchers and practitioners of fields such as astrophysics that requires pictorial representation of the energy levels and electronic transitions of elements.

  5. From heavy ions to exotic atoms

    OpenAIRE

    Indelicato, Paul; Trassinelli, Martino

    2005-01-01

    We review a number of experiments and theoretical calculations on heavy ions and exotic atoms, which aim at providing informations on fundamental interactions. Among those are propositions of experiments for parity violation measurements in heavy ions and high-precision mesurements of He-like transition energies in highly charged ions. We also describe recent experiments on pionic atoms, that make use of highly-charged ion transitions to obtain accurate measurements of strong interaction shif...

  6. From heavy ions to exotic atoms

    OpenAIRE

    Indelicato, Paul; Trassinelli, Martino

    2005-01-01

    We review a number of experiments and theoretical calculations on heavy ions and exotic atoms, which aim at providing informations on fundamental interactions. Among those are propositions of experiments for parity violation measurements in heavy ions and high-precision mesurements of He-like transition energies in highly charged ions. We also describe recent experiments on pionic atoms, that make use of highly-charged ion transitions to obtain accurate measurements of strong interaction shif...

  7. 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...

  8. Dynamics in atomic signaling games

    KAUST Repository

    Fox, Michael J.

    2015-04-08

    We study an atomic signaling game under stochastic evolutionary dynamics. There are a finite number of players who repeatedly update from a finite number of available languages/signaling strategies. Players imitate the most fit agents with high probability or mutate with low probability. We analyze the long-run distribution of states and show that, for sufficiently small mutation probability, its support is limited to efficient communication systems. We find that this behavior is insensitive to the particular choice of evolutionary dynamic, a property that is due to the game having a potential structure with a potential function corresponding to average fitness. Consequently, the model supports conclusions similar to those found in the literature on language competition. That is, we show that efficient languages eventually predominate the society while reproducing the empirical phenomenon of linguistic drift. The emergence of efficiency in the atomic case can be contrasted with results for non-atomic signaling games that establish the non-negligible possibility of convergence, under replicator dynamics, to states of unbounded efficiency loss.

  9. Number of Compositions and Convolved Fibonacci numbers

    CERN Document Server

    Janjic, Milan

    2010-01-01

    We consider two type of upper Hessenberg matrices which determinants are Fibonacci numbers. Calculating sums of principal minors of the fixed order of the first type leads us to convolved Fibonacci numbers. Some identities for these and for Fibonacci numbers are proved. We also show that numbers of compositions of a natural number with fixed number of ones appear as coefficients of characteristic polynomial of a Hessenberg matrix which determinant is a Fibonacci number. We derive the explicit formula for the number of such compositions, in terms of convolutions of Fibonacci numbers.

  10. 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.

  11. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1995-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is promarily 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.

  12. The Software Atom

    CERN Document Server

    Javanainen, Juha

    2016-01-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  13. The Software Atom

    Science.gov (United States)

    Javanainen, Juha

    2017-03-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  14. Atomicity in Electronic Commerce,

    Science.gov (United States)

    1996-01-01

    tremendous demand for the ability to electronically buy and sell goods over networks. Electronic commerce has inspired a large variety of work... commerce . It then briefly surveys some major types of electronic commerce pointing out flaws in atomicity. We pay special attention to the atomicity...problems of proposals for digital cash. The paper presents two examples of highly atomic electronic commerce systems: NetBill and Cryptographic Postage Indicia.

  15. Atomic homodyne detection of weak atomic transitions.

    Science.gov (United States)

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  16. Atom probe crystallography

    National Research Council Canada - National Science Library

    Gault, Baptiste; Moody, Michael P; Cairney, Julie M; Ringer, Simon P

    2012-01-01

    This review addresses new developments in the emerging area of "atom probe crystallography", a materials characterization tool with the unique capacity to reveal both composition and crystallographic...

  17. Dephasing in an atom

    OpenAIRE

    2011-01-01

    When an atom in vacuum is near a surface of a dielectric the energy of a fluctuating electromagnetic field depends on a distance between them resulting, as known, in the force called van der Waals one. Besides this fluctuation phenomenon there is one associated with formation of a mean electric field which is equivalent to an order parameter. In this case atomic electrons are localized within atomic distances close to the atom and the total ground state energy is larger, compared to the bare ...

  18. Dipolar exchange induced transparency with Rydberg atoms

    Science.gov (United States)

    Petrosyan, David

    2017-03-01

    A three-level atomic medium can be made transparent to a resonant probe field in the presence of a strong control field acting on an adjacent atomic transition to a long-lived state, which can be represented by a highly excited Rydberg state. The long-range interactions between the Rydberg state atoms then translate into strong, non-local, dispersive or absorptive interactions between the probe photons, which can be used to achieve deterministic quantum logic gates and single photon sources. Here we show that long-range dipole–dipole exchange interaction with one or more spins—two-level systems represented by atoms in suitable Rydberg states—can play the role of control field for the optically dense medium of atoms. This induces transparency of the medium for a number of probe photons n p not exceeding the number of spins n s , while all the excess photons are resonantly absorbed upon propagation. In the most practical case of a single spin atom prepared in the Rydberg state, the medium is thus transparent only to a single input probe photon. For larger number of spins n s , all n p ≤ n s photon components of the probe field would experience transparency but with an n p -dependent group velocity.

  19. Doping Scheme in Atomic Chain Electronics

    Science.gov (United States)

    Toshishige, Yamada

    1997-01-01

    Due to the dramatic reduction in MOS size, there appear many unwanted effects. In these small devices, the number of dopant atoms in the channel is not macroscopic and electrons may suffer significantly different scattering from device to device since the spatial distribution of dopant atoms is no longer regarded as continuous. This prohibits integration, while it is impossible to control such dopant positions within atomic scale. A fundamental solution is to create electronics with simple but atomically precise structures, which could be fabricated with recent atom manipulation technology. All the constituent atoms are placed as planned, and then the device characteristics are deviation-free, which is mandatory for integration. Atomic chain electronics belongs to this category. Foreign atom chains or arrays form devices, and they are placed on the atomically flat substrate surface. We can design the band structure and the resultant Fermi energy of these structures by manipulating the lattice constant. Using the tight-binding theory with universal parameters, it has been predicted that isolated Si chains and arrays are metallic, Mg chains are insulating, and Mg arrays have metallic and insulating phases [1]. The transport properties along a metallic chain have been studied, emphasizing the role of the contact to electrodes [2]. For electronic applications, it is essential to establish a method to dope a semiconducting chain, which is to control the Fermi energy position without altering the original band structure. If we replace some of the chain atoms with dopant atoms randomly, the electrons will see random potential along die chain and will be localized strongly in space (Anderson localization). However, if we replace periodically, although the electrons can spread over the chain, there will generally appear new bands and band gaps reflecting the new periodicity of dopant atoms. This will change the original band structure significantly. In order to overcome

  20. Atoms in astrophysics

    CERN Document Server

    Eissner, W; Hummer, D; Percival, I

    1983-01-01

    It is hard to appreciate but nevertheless true that Michael John Seaton, known internationally for the enthusiasm and skill with which he pursues his research in atomic physics and astrophysics, will be sixty years old on the 16th of January 1983. To mark this occasion some of his colleagues and former students have prepared this volume. It contains articles that de­ scribe some of the topics that have attracted his attention since he first started his research work at University College London so many years ago. Seaton's association with University College London has now stretched over a period of some 37 years, first as an undergraduate student, then as a research student, and then, successively, as Assistant Lecturer, Lecturer, Reader, and Professor. Seaton arrived at University College London in 1946 to become an undergraduate in the Physics Department, having just left the Royal Air Force in which he had served as a navigator in the Pathfinder Force of Bomber Command. There are a number of stories of ho...

  1. Helium atom scattering from surfaces

    CERN Document Server

    1992-01-01

    High resolution helium atom scattering can be applied to study a number of interesting properties of solid surfaces with great sensitivity and accuracy. This book treats in detail experimental and theoretical aspects ofthis method as well as all current applications in surface science. The individual chapters - all written by experts in the field - are devoted to the investigation of surface structure, defect shapes and concentrations, the interaction potential, collective and localized surface vibrations at low energies, phase transitions and surface diffusion. Over the past decade helium atom scattering has gained widespread recognitionwithin the surface science community. Points in its favour are comprehensiveunderstanding of the scattering theory and the availability of well-tested approximation to the rigorous theory. This book will be invaluable to surface scientists wishing to make an informed judgement on the actual and potential capabilities of this technique and its results.

  2. Effect of energetic oxygen atoms on neutral density models.

    Science.gov (United States)

    Rohrbaugh, R. P.; Nisbet, J. S.

    1973-01-01

    The dissociative recombination of O2(+) and NO(+) in the F region results in the production of atomic oxygen and atomic nitrogen with substantially greater kinetic energy than the ambient atoms. In the exosphere these energetic atoms have long free paths. They can ascend to altitudes of several thousand kilometers and can travel horizontally to distances of the order of the earth's radius. The distribution of energetic oxygen atoms is derived by means of models of the ion and neutral densities for quiet and disturbed solar conditions. A distribution technique is used to study the motion of the atoms in the collision-dominated region. Ballistic trajectories are calculated in the spherical gravitational field of the earth. The present calculations show that the number densities of energetic oxygen atoms predominate over the ambient atomic oxygen densities above 1000 km under quiet solar conditions and above 1600 km under disturbed solar conditions.

  3. Evanescent Wave Atomic Mirror

    Science.gov (United States)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  4. Atomic Scale Plasmonic Switch.

    Science.gov (United States)

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  5. Greek Atomic Theory.

    Science.gov (United States)

    Roller, Duane H. D.

    1981-01-01

    Focusing on history of physics, which began about 600 B.C. with the Ionian Greeks and reaching full development within three centuries, suggests that the creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists. (Author/SK)

  6. 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.

  7. 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…

  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. Tunneling Dynamics Between Atomic and Molecular Bose-Einstein Condensates

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang-Yong

    2004-01-01

    Tunneling dynamics of multi-atomic molecules between atomic and multi-atomic molecular Bose-Einstein condensates with Feshbach resonance is investigated.It is indicated that the tunneling in the two Bose-Einstein condensates depends on not only the inter-atomic-molecular nonlinear interactions and the initial number of atoms in these condensates,but also the tunneling coupling between the atomic condensate and the multi-atomic molecular condensate.It is discovered that besides oscillating tunneling current between the atomic condensate and the multi-atomic molecular condensate,the nonlinear multi-atomic molecular tunneling dynamics sustains a self-locked population imbalance:a macroscopic quantum self-trapping effect.The influence of de-coherence caused by non-condensate atoms on the tunneling dynamics is studied.It is shown that de-coherence suppresses the multi-atomic molecular tunneling.Moreover,the conception of the molecular Bose-Einstein condensate,which is different from the conventional single-atomic Bose-Einstein condensate,is specially emphasized in this paper.

  10. Single-atom manipulations in a microscopic dipole trap.

    Science.gov (United States)

    Reymond, Georges; Schlosser, Nicolas; Protsenko, Igor; Grangier, Philippe

    2003-07-15

    We have realized a very small optical dipole trap that is designed to store and manipulate individual atoms. Due to the very small dipole-trap volume, a 'collisional blockade' mechanism locks the average number of trapped atoms at a value of 0.5 over a large range of loading rates. Here we describe methods to characterize the motion of a single trapped atom, and we also demonstrate the possibility of trapping two atoms individually at a short distance apart. Finally, we study theoretically the possibility to perform 'conditional quantum logic' by scattering photons from two such atoms.

  11. Calculation of Al-Zn diagram from central atoms model

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A slightly modified central atoms model was proposed. The probabilities of various clusters with the central atoms and their nearest neighboring shells can be calculated neglecting the assumption of the param eter of energy in the central atoms model in proportion to the number of other atoms i (referred with the central atom). A parameter Pα is proposed in this model, which equals to reciprocal of activity coefficient of a component, therefore, the new model can be understood easily. By this model, the Al-Zn phase diagram and its thermodynamic properties were calculated, the results coincide with the experimental data.

  12. Preparation of two and four-atom entangled states

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A scheme for preparing two and four-atom entangled states is presented. It is based on atom-cavity-field interactions. Firatly, the cav ity is prepared in the superposition of the number states through the atom under going a two-photon transition, the secondly, the two or four identical two-lev el atoms, which are all initially in their ground states, are sent through the c avity sequentially and can make resonant single-photon transition in the cavity . Then atomic entangled states are created and the cavity is left in the vacuum state.

  13. 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...

  14. QSPR modeling with electrotopological state index for atom type for predicting octane number of paraffins%基于原子类型电拓扑状态指数的 QSPR 模型预测链烷烃辛烷值

    Institute of Scientific and Technical Information of China (English)

    仇爱波; 周如金; 邱松山; 曾兴业

    2014-01-01

    为了研究化合物结构与其辛烷值之间的相关性,以原子类型电拓扑状态指数作为描述符表征分子的结构特征,从40个样本中选取30种链烷烃作为训练集,对研究法辛烷值选取8个作为测试集,对马达法辛烷值选取7个作为预测集,利用SPSS 软件进行多元线性回归,建立了辛烷值的定量结构-性质关系。得到的研究法辛烷值和马达法辛烷值预测模型复相关系数分别为0.965、0.955和均方根误差分别为5.4338、4.9404,并对模型进行内部和外部验证。结果表明,该模型具有较好的稳定性及预测能力。%In order to study the structure-octane number relationship of compounds, atom-type electrotopological state indices were used as molecular structure descriptors. The dataset of 40 paraffins was randomly divided into a training set containing 30 paraffins, a testing set consisting of 8 paraffins for research octane number and a testing set with 7 paraffins for motor octane number. SPSS software was employed to process multiple linear regression. A prediction model based on quantitative structure-property relationship (QSPR) studies was proposed, and the correlation coefficient and root-mean-square error of the model were 0.965 and 5.4338 for RON, 0.955 and 4.9404 for MON, respectively. Both internal and external validations were performed to validate the performances of the resulting model. The results showed that the model has good stability and prediction ability.

  15. The Super Patalan Numbers

    OpenAIRE

    Richardson, Thomas M.

    2014-01-01

    We introduce the super Patalan numbers, a generalization of the super Catalan numbers in the sense of Gessel, and prove a number of properties analagous to those of the super Catalan numbers. The super Patalan numbers generalize the super Catalan numbers similarly to how the Patalan numbers generalize the Catalan numbers.

  16. Electron transport through monovalent atomic wires

    DEFF Research Database (Denmark)

    Lee, Y. J.; Brandbyge, Mads; Puska, M. J.

    2004-01-01

    Using a first-principles density-functional method we model electron transport through linear chains of monovalent atoms between two bulk electrodes. For noble-metal chains the transport resembles that for free electrons over a potential barrier whereas for alkali-metal chains resonance states...... at the chain determine the conductance. As a result, the conductance for noble-metal chains is close to one quantum of conductance, and it oscillates moderately so that an even number of chain atoms yields a higher value than an odd number. The conductance oscillations are large for alkali-metal chains...

  17. New qualitative results of the atomic theory

    Science.gov (United States)

    Dyugaev, A. M.; Lebedeva, E. V.

    2016-11-01

    The polarizability α of many atoms and positive ions is related to their energy gap Δ and valence m by the expression αΔ2 ≅ m (in atomic units). The parameter Δ corresponds to a dipolar transition from the ground state to the first excited P state without a change in the principal quantum number n. This relation holds for univalent ( m = 1) Na, K, Rb, Cs, Fr and bivalent ( m = 2) Mg, Ca, Zn, Sr, Cd, Ba, Yb, Hg atoms. The above relation agrees with the experiment for positive ions Mg+ and Ca+ ( m = 1) and Al+ and Ga+ ( m = 2). The polarizability has been found for atoms and ions of the type Zn+, In+, Tl+, for which experimental data are unavailable. A method of calculating α for ions of the types C++, Al++, Si++ and Si+++, P+++, As+++ has been suggested based on the approximate relation α ≅(2/30)2/ m with the parameter 0 expressed in terms of the valence m, the charge number q of the atomic or ionic residue, and the ionization potential {J_q} = {{q^2}}/{2v_s^2} as {0 on the parameter νs has been derived by analytical continuation from the integer values νs = 1 and 2. A variational estimate of the van der Waals constant characterizing the interaction of two spherically symmetric atoms at large distances has been given.

  18. Atom-Light Interactions in Photonic Crystals

    CERN Document Server

    Goban, A; Yu, S -P; Hood, J D; Muniz, J A; Lee, J H; Martin, M J; McClung, A C; Choi, K S; Chang, D E; Painter, O; Kimble, H J

    2013-01-01

    The integration of nanophotonics and atomic physics has been a long-sought goal that would open new frontiers for optical physics. Here, we report the development of the first integrated optical circuit with a photonic crystal capable of both localizing and interfacing atoms with guided photons in the device. By aligning the optical bands of a photonic crystal waveguide (PCW) with selected atomic transitions, our platform provides new opportunities for novel quantum transport and many-body phenomena by way of photon-mediated atomic interactions along the PCW. From reflection spectra measured with average atom number N = 1.1$\\pm$0.4, we infer that atoms are localized within the PCW by Casimir-Polder and optical dipole forces. The fraction of single-atom radiative decay into the PCW is $\\Gamma_{\\rm 1D}/\\Gamma'$ = 0.32$\\pm$0.08, where $\\Gamma_{1D}$ is the rate of emission into the guided mode and $\\Gamma'$ is the decay rate into all other channels. $\\Gamma_{\\rm 1D}/\\Gamma'$ is quoted without enhancement due to a...

  19. 78 FR 58571 - Maine Yankee Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic...

    Science.gov (United States)

    2013-09-24

    ... Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic Electric Company... Power Company (Maine Yankee), Connecticut Yankee Atomic Power Company (Connecticut Yankee), and the Yankee Atomic Electric Company (Yankee Atomic) (together, ``licensees'' or ``the Yankee Companies'')...

  20. Linear atomic quantum coupler

    CERN Document Server

    El-Orany, Faisal A A

    2009-01-01

    In this paper, we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of them includes a localized and/or a trapped atom. These waveguides are placed close enough to allow exchanging energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way, i.e. as the Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via evanescent wave. We present the Hamiltonian for the system and deduce the exact form for the wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional linear coupler, the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions, the system can yield the results of the two-m...

  1. Atomic model of liquid pure Fe

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using a θ-θX-ray diffractometer, the liquid structure of pure Fewas investigated and the diffraction intensity, structure factor, pair distribution function as well as the coordination number and atomic distance were obtained. The experimental results showed that there was also a pre-peak on the curve of the structure factor of liquid pure Fe. The pre-peak is a mark of medium-range order in melts. According to the characteristics of pre-peak, an atomic model of liquid pure Fe is constructed, namely, the structure of liquid pure Fe is a combination of clusters consisting of bcc cells with shared vertexes and other atoms with random dense atom distribution.

  2. Implementing quantum electrodynamics with ultracold atomic systems

    CERN Document Server

    Kasper, V; Jendrzejewski, F; Oberthaler, M K; Berges, J

    2016-01-01

    We discuss the experimental engineering of model systems for the description of QED in one spatial dimension via a mixture of bosonic $^{23}$Na and fermionic $^6$Li atoms. The local gauge symmetry is realized in an optical superlattice, using heteronuclear boson-fermion spin-changing interactions which preserve the total spin in every local collision. We consider a large number of bosons residing in the coherent state of a Bose-Einstein condensate on each link between the fermion lattice sites, such that the behavior of lattice QED in the continuum limit can be recovered. The discussion about the range of possible experimental parameters builds, in particular, upon experiences with related setups of fermions interacting with coherent samples of bosonic atoms. We determine the atomic system's parameters required for the description of fundamental QED processes, such as Schwinger pair production and string breaking. This is achieved by benchmark calculations of the atomic system and of QED itself using function...

  3. Coupling ultracold atoms to mechanical oscillators

    CERN Document Server

    Hunger, David; Korppi, Maria; Jöckel, Andreas; Hänsch, Theodor W; Treutlein, Philipp

    2011-01-01

    In this article we discuss and compare different ways to engineer an interface between ultracold atoms and micro- and nanomechanical oscillators. We start by analyzing a direct mechanical coupling of a single atom or ion to a mechanical oscillator and show that the very different masses of the two systems place a limit on the achievable coupling constant in this scheme. We then discuss several promising strategies for enhancing the coupling: collective enhancement by using a large number of atoms in an optical lattice in free space, coupling schemes based on high-finesse optical cavities, and coupling to atomic internal states. Throughout the manuscript we discuss both theoretical proposals and first experimental implementations.

  4. Laser cooling and trapping of ytterbium atoms

    Institute of Scientific and Technical Information of China (English)

    Xin-ye XU; Wen-li WANG; Qing-hong ZHOU; Guo-hui LI; Hai-ling JIANG; Lin-fang CHEN; Jie YE; Zhi-hong ZHOU; Yin CAI; Hai-yao TANG; Min ZHOU

    2009-01-01

    The experiments on the laser cooling and trapping of ytterbium atoms are reported, including the two-dimensional transversal cooling, longitudinal velocity Zeeman deceleration, and a magneto-optical trap with a broadband transition at a wavelength of 399 nm. The magnetic field distributions along the axis of a Zeeman slower were measured and in a good agreement with the calculated results. Cold ytterbium atoms were produced with a number of about 107 and a temperature of a few milli-Kelvin.In addition, using a 556-nm laser, the excitations of cold tterbium atoms at 1S0-3p1 transition were observed. The ytterbium atoms will be further cooled in a 556-nm magneto-optical trap and loaded into a three-dimensional optical lattice to make an ytterbium optical clock.

  5. Atomic Structure Theory Lectures on Atomic Physics

    CERN Document Server

    Johnson, Walter R

    2007-01-01

    Atomic Structure Theory is a textbook for students with a background in quantum mechanics. The text is designed to give hands-on experience with atomic structure calculations. Material covered includes angular momentum methods, the central field Schrödinger and Dirac equations, Hartree-Fock and Dirac-Hartree-Fock equations, multiplet structure, hyperfine structure, the isotope shift, dipole and multipole transitions, basic many-body perturbation theory, configuration interaction, and correlation corrections to matrix elements. Numerical methods for solving the Schrödinger and Dirac eigenvalue problems and the (Dirac)-Hartree-Fock equations are given as well. B-spline basis sets are used to carry out sums arising in higher-order many-body calculations. Illustrative problems are provided, together with solutions. FORTRAN programs implementing the numerical methods in the text are included.

  6. Atom-atom excitation in shock waves in argon-oxygen mixture

    Energy Technology Data Exchange (ETDEWEB)

    Ezumi, Hiromichi; Kawamura, Masahiko

    1987-05-01

    The slope constants of the excitational cross-section for atom-atom and atom-electron collisions were generally considered and that for the oxygen atom-atom collision S/sub 0-0/ was determined to be 3.14 x 10/sup -19/ cm/sup 2//eV. Using the newly determined value of S/sub 0-0/, the calculation of the ionizing shock structure of argon-oxygen mixture was made at shock Mach number M/sub S/ = 17.1 and the initial pressure P/sub 1/ = 2.85 Torr. From the comparison of the calculated value of relaxation length with the experimental one, it was proved that the experimental result can be explained well by the present determined value of S/sub 0-0/.

  7. Inside the Hydrogen Atom

    CERN Document Server

    Nowakowski, M; Fierro, D Bedoya; Manjarres, A D Bermudez

    2016-01-01

    We apply the non-linear Euler-Heisenberg theory to calculate the electric field inside the hydrogen atom. We will demonstrate that the electric field calculated in the Euler-Heisenberg theory can be much smaller than the corresponding field emerging from the Maxwellian theory. In the hydrogen atom this happens only at very small distances. This effect reduces the large electric field inside the hydrogen atom calculated from the electromagnetic form-factors via the Maxwell equations. The energy content of the field is below the pair production threshold.

  8. 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.

  9. Atom probe tomography today

    Directory of Open Access Journals (Sweden)

    Alfred Cerezo

    2007-12-01

    Full Text Available This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks and also the atomic-level characterization of interfaces in multilayers, oxide films, and semiconductor materials and devices.

  10. 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.

  11. Rydberg atoms in astrophysics

    CERN Document Server

    Gnedin, Yu N; Ignjatovic, Lj M; Sakan, N M; Sreckovic, V A; Zakharov, M Yu; Bezuglov, N N; Klycharev, A N; 10.1016/j.newar.2009.07.003

    2012-01-01

    Elementary processes in astrophysical phenomena traditionally attract researchers attention. At first this can be attributed to a group of hemi-ionization processes in Rydberg atom collisions with ground state parent atoms. This processes might be studied as a prototype of the elementary process of the radiation energy transformation into electrical one. The studies of nonlinear mechanics have shown that so called regime of dynamic chaos should be considered as typical, rather than exceptional situation in Rydberg atoms collision. From comparison of theory with experimental results it follows that a such kind of stochastic dynamic processes, occurred during the single collision, may be observed.

  12. Atomic and molecular supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.

    1997-12-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  13. EINSTEIN, SCHROEDINGER, AND ATOM

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-03-01

    Full Text Available In this paper, we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation and the Schrodinger equation as well. The solutions of the Einstein equations describing the stationary states of arbitrary quantum and classical systems with central symmetry have been obtained. Einstein’s atom model has been developed, and proved that atoms and atomic nuclei can be represented as standing gravitational waves

  14. Single-atom nanoelectronics

    CERN Document Server

    Prati, Enrico

    2013-01-01

    Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also from the point of view of large-scale industrial production. The publication provides a comprehensive picture of the state of the art at the cutting edge and constitutes a milestone in the emerging field of beyond-CMOS technology. Although there are

  15. History of early atomic clocks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, N.F. [Harvard Univ., Cambridge, MA (United States). Lyman Lab. of Physics

    2005-06-01

    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)

  16. PREFACE: Fourth International Symposium on Atomic Technology

    Science.gov (United States)

    Okada, Shigefumi

    2010-04-01

    The International Symposium on Atomic Technology (ISAT) is held every year. The 4th Symposium (ISAT-4) was held on November 18-19, 2009 at the Seaside Hotel MAIKO VILLA KOBE, Kobe City, Japan presided by the "Atomic Technology Project". The ISAT-4 symposium was intended to offer a forum for the discussion on the latest progress in the atomic technologies. The symposium was attended by 107 delegates. There were 10 invited and 6 oral presentations. The number of poster presentations was 69. From all the contributions, 22 papers selected through review process are contained in this volume. The "Atomic Technology Project" was started in 2006 as a joint project of three institutions; (1) the Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University (CAMT), (2) the Tsukuba Research Center for Interdisciplinary Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba (TIMS) and (3) the Polyscale Technology Research Center, Research Institute for Science and Technology, Tokyo University of Science (PTRC), each of which were independently pursuing nano-technologies and was developing atomic scale operation and diagnostics, functional materials, micro processing and device. The project is funded by the Ministry of Education, Culture, Sports, Science and Technology of Japan. The goal of the project is to contribute to the development of atomic-scale science and technologies such as functional molecules, biomaterials, and quantum functions of atomic-scale structures. Shigefumi Okada Conference Chair Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita-city, Osaka 565-0871, Japan. Conference photograph Kobe photograph

  17. Atomical Grothendieck categories

    Directory of Open Access Journals (Sweden)

    C. Năstăsescu

    2003-01-01

    Full Text Available Motivated by the study of Gabriel dimension of a Grothendieck category, we introduce the concept of atomical Grothendieck category, which has only two localizing subcategories, and we give a classification of this type of Grothendieck categories.

  18. Atomic bomb health benefits.

    Science.gov (United States)

    Luckey, T D

    2008-01-01

    Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation, leukemia and solid tissue cancer mortality rates, and increased average lifespan. Each study exhibits a threshold that repudiates the LNT dogma. The average threshold for acute exposures to atomic bombs is about 100 cSv. Conclusions from these studies of atomic bomb survivors are: One burst of low dose irradiation elicits a lifetime of improved health.Improved health from low dose irradiation negates the LNT paradigm.Effective triage should include radiation hormesis for survivor treatment.

  19. 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.

  20. Zeeman atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    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. (WHK)

  1. Atomic & Molecular Interactions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-07-12

    The Gordon Research Conference (GRC) on Atomic & 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.

  2. Atomic Interferometry Project

    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...

  3. On Number of Compositions of Natural Numbers

    CERN Document Server

    Janjic, Milan

    2010-01-01

    We first give a combinatorial interpretation of coefficients of Chebyshev polynomials, which allows us to connect them with compositions of natural numbers. Then we describe a relationship between the number of compositions of a natural number in which a certain number of parts are p-1, and other parts are not less than p with compositions in which all parts are not less than p. Then we find a relationship between principal minors of a type of Hessenberg matrices and compositions of natural numbers.

  4. Atom probe tomography today

    OpenAIRE

    Alfred Cerezo; Peter H. Clifton; Mark J. Galtrey; Humphreys, Colin J.; Kelly, Thomas. F.; David J. Larson; Sergio Lozano-Perez; Marquis, Emmanuelle A.; Oliver, Rachel A.; Gang Sha; Keith Thompson; Mathijs Zandbergen; Roger L. Alvis

    2007-01-01

    This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments) but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks) and also...

  5. Metal atomization spray nozzle

    Science.gov (United States)

    Huxford, Theodore J.

    1993-01-01

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal.

  6. Optical atomic magnetometer

    Science.gov (United States)

    Budker, Dmitry; Higbie, James; Corsini, Eric P

    2013-11-19

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  7. 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.

  8. 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.

  9. Cavity enhanced atomic magnetometry

    OpenAIRE

    Herbert Crepaz; Li Yuan Ley; Rainer Dumke

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage...

  10. On Multiplying Negative Numbers.

    Science.gov (United States)

    Crowley, Mary L.; Dunn, Kenneth A.

    1985-01-01

    Comments on the history of negative numbers, some methods that can be used to introduce the multiplication of negative numbers to students, and an explanation of why the product of two negative numbers is a positive number are included. (MNS)

  11. Submicrometer position control of single trapped neutral atoms

    OpenAIRE

    Dotsenko, I.; Alt, W; Khudaverdyan, M.; Kuhr, S.; Meschede, D.; Miroshnychenko, Y.; Schrader, D.; Rauschenbeutel, A.

    2004-01-01

    We optically detect the positions of single neutral cesium atoms stored in a standing wave dipole trap with a sub-wavelength resolution of 143 nm rms. The distance between two simultaneously trapped atoms is measured with an even higher precision of 36 nm rms. We resolve the discreteness of the interatomic distances due to the 532 nm spatial period of the standing wave potential and infer the exact number of trapping potential wells separating the atoms. Finally, combining an initial position...

  12. Dual-Beam Atom Laser Driven by Spinor Dynamics

    Science.gov (United States)

    Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Aveline, David

    2007-01-01

    An atom laser now undergoing development simultaneously generates two pulsed beams of correlated Rb-87 atoms. (An atom laser is a source of atoms in beams characterized by coherent matter waves, analogous to a conventional laser, which is a source of coherent light waves.) The pumping mechanism of this atom laser is based on spinor dynamics in a Bose-Einstein condensate. By virtue of the angular-momentum conserving collisions that generate the two beams, the number of atoms in one beam is correlated with the number of atoms in the other beam. Such correlations are intimately linked to entanglement and squeezing in atomic ensembles, and atom lasers like this one could be used in exploring related aspects of Bose-Einstein condensates, and as components of future sensors relying on atom interferometry. In this atom-laser apparatus, a Bose-Einstein condensate of about 2 x 10(exp 6) Rb-87 atoms at a temperature of about 120 micro-K is first formed through all-optical means in a relatively weak singlebeam running-wave dipole trap that has been formed by focusing of a CO2-laser beam. By a technique that is established in the art, the trap is loaded from an ultrahigh-vacuum magnetooptical trap that is, itself, loaded via a cold atomic beam from an upstream two-dimensional magneto-optical trap that resides in a rubidium-vapor cell that is differentially pumped from an adjoining vacuum chamber, wherein are performed scientific observations of the beams ultimately generated by the atom laser.

  13. Fast transport, atom sample splitting, and single-atom qubit supply in two-dimensional arrays of optical microtraps

    CERN Document Server

    Schlosser, Malte; Gierl, Christian; Teichmann, Stephan; Tichelmann, Sascha; Birkl, Gerhard; 10.1088/1367-2630/14/12/123034

    2013-01-01

    Two-dimensional arrays of optical micro-traps created by microoptical elements present a versatile and scalable architecture for neutral atom quantum information processing, quantum simulation, and the manipulation of ultra-cold quantum gases. In this article, we demonstrate advanced capabilities of this approach by introducing novel techniques and functionalities as well as the combined operation of previously separately implemented functions. We introduce piezo-actuator based transport of atom ensembles over distances of more than one trap separation, examine the capabilities of rapid atom transport provided by acousto-optical beam steering, and analyze the adiabaticity limit for atom transport in these configurations. We implement a spatial light modulator with 8-bit transmission control for the per-site adjustment of the trap depth and the number of atoms loaded. We combine single-site addressing, trap depth control, and atom transport in one configuration for demonstrating the splitting of atom ensembles...

  14. All Square Chiliagonal Numbers

    Science.gov (United States)

    A?iru, Muniru A.

    2016-01-01

    A square chiliagonal number is a number which is simultaneously a chiliagonal number and a perfect square (just as the well-known square triangular number is both triangular and square). In this work, we determine which of the chiliagonal numbers are perfect squares and provide the indices of the corresponding chiliagonal numbers and square…

  15. Effective potentials for atom-atom interaction at low temperatures

    OpenAIRE

    Gao, Bo

    2002-01-01

    We discuss the concept and design of effective atom-atom potentials that accurately describe any physical processes involving only states around the threshold. The existence of such potentials gives hope to a quantitative, and systematic, understanding of quantum few-atom and quantum many-atom systems at relatively low temperatures.

  16. Study on the fine control of atoms by coherent interaction

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jae Min; Rho, S. P.; Park, H. M.; Lee, K. S.; Rhee, Y. J.; Yi, J. H.; Jeong, D. Y.; Ko, K. H.; Lee, J. M.; Kim, M.K

    2000-01-01

    Study on one dimensional atom cooling and trapping process which is basic to the development of atom manipulation technology has been performed. A Zeeman slower has been designed and manufactured for efficient cooling of atoms. The speed of atoms finally achieved is as slow as 15 m/s with proper cooling conditions. By six circularly-polarized laser beams and quadrupole magnetic field, the atoms which have been slowed down by zeeman slower have been trapped in a small spatial region inside MOT. The higher the intensity of the slowing laser is the more is the number of atoms slowed and the maximum number of atoms trapped has been 10{sup 8}. The atoms of several tens of {mu}K degree have been trapped by controlling the intensity of trapping laser and intensity gradient of magnetic field. EIT phenomena caused by atomic coherent interaction has been studied for the development of atom optical elements. For the investigation of the focusing phenomena induced by the coherent interaction, experimental measurements and theoretical analysis have been performed. Spatial dependency of spectrum and double distribution signal of coupling laser have been obtained. The deflection of laser beams utilizing the EIT effects has also been considered. (author)

  17. Teleportation of Atomic States for Atoms in a Lambda Configuration

    CERN Document Server

    Guerra, E S

    2004-01-01

    In this article we discuss a scheme of teleportation of atomic states making use of three-level lambda atoms. The experimental realization proposed makes use of cavity QED involving the interaction of Rydberg atoms with a micromaser cavity prepared in a coherent state. We start presenting a scheme to prepare atomic EPR states involving two-level atoms via the interaction of these atoms with a cavity. In our scheme the cavity and some atoms play the role of auxiliary systems used to achieve the teleportation.

  18. 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, 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'. © 2017 The Author(s).

  19. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    Hitesh Sharma; S Prakash

    2007-04-01

    We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method. Wills and Harrison interatomic potential is used to calculate the atomic force constants, the dynamical matrix and the impurity-induced forces. We have thoroughly investigated the atomic displacements using impurities from 3d, 4d and 5d series in the same host metal and the same impurity in different hosts. We have observed a systematic pattern in the atomic displacements for Cr-, Fe-, Nb-, Mo-, Ta- and W-based dilute alloys. The atomic displacements are found to increase with increase in the number of d electrons for all alloys considered except for V dilute alloys. The 3d impurities are found to be more easily dissolved in the 3d host metals than 4d or 5d TMs whereas 4d and 5d impurities show more solubility in 4d and 5d TMs. In general, the relaxation energy calculation suggests that impurities may be easily solvable in 5d TM hosts when compared to 3d or 4d TMs.

  20. Gravitational wave detection using atom interferometry

    Science.gov (United States)

    Hogan, Jason

    2016-05-01

    The advent of gravitational wave astronomy promises to provide a new window into the universe. Low frequency gravitational waves below 10 Hz are expected to offer rich science opportunities both in astrophysics and cosmology, complementary to signals in LIGO's band. Detector designs based on atom interferometry have a number of advantages over traditional approaches in this band, including the possibility of substantially reduced antenna baseline length in space and high isolation from seismic noise for a terrestrial detector. In particular, atom interferometry based on the clock transition in group II atoms offers tantalizing new possibilities. Such a design is expected to be highly immune to laser frequency noise because the signal arises strictly from the light propagation time between two ensembles of atoms. This would allow for a gravitational wave detector with a single linear baseline, potentially offering advantages in cost and design flexibility. In support of these proposals, recent progress in long baseline atom interferometry in a 10-meter drop tower has enabled observation of matter wave interference with atomic wavepacket separations exceeding 50 cm and interferometer durations of more than 2 seconds. This approach can provide ground-based proof-of-concept demonstrations of many of the technical requirements of both terrestrial and satellite gravitational wave detectors.

  1. 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'.

  2. Accurate atom-mapping computation for biochemical reactions.

    Science.gov (United States)

    Latendresse, Mario; Malerich, Jeremiah P; Travers, Mike; Karp, Peter D

    2012-11-26

    The complete atom mapping of a chemical reaction is a bijection of the reactant atoms to the product atoms that specifies the terminus of each reactant atom. Atom mapping of biochemical reactions is useful for many applications of systems biology, in particular for metabolic engineering where synthesizing new biochemical pathways has to take into account for the number of carbon atoms from a source compound that are conserved in the synthesis of a target compound. Rapid, accurate computation of the atom mapping(s) of a biochemical reaction remains elusive despite significant work on this topic. In particular, past researchers did not validate the accuracy of mapping algorithms. We introduce a new method for computing atom mappings called the minimum weighted edit-distance (MWED) metric. The metric is based on bond propensity to react and computes biochemically valid atom mappings for a large percentage of biochemical reactions. MWED models can be formulated efficiently as Mixed-Integer Linear Programs (MILPs). We have demonstrated this approach on 7501 reactions of the MetaCyc database for which 87% of the models could be solved in less than 10 s. For 2.1% of the reactions, we found multiple optimal atom mappings. We show that the error rate is 0.9% (22 reactions) by comparing these atom mappings to 2446 atom mappings of the manually curated Kyoto Encyclopedia of Genes and Genomes (KEGG) RPAIR database. To our knowledge, our computational atom-mapping approach is the most accurate and among the fastest published to date. The atom-mapping data will be available in the MetaCyc database later in 2012; the atom-mapping software will be available within the Pathway Tools software later in 2012.

  3. Development of a compact cold-atom atomic clock based on coherent population trapping

    Science.gov (United States)

    Blanshan, Eric M.

    Field-grade atomic clocks capable of primary standard performance in compact physics packages would be of significant value in a variety of applications ranging from network synchronization and secure communications to GPS hold-over and inertial navigation. A cold-atom coherent population trapping (CACPT) clock featuring laser-cooled atoms and pulsed Ramsey interrogation is a strong candidate for this technology if the principal frequency shifts can be controlled and the performance degradation associated with miniaturization can be overcome. In this thesis, research focused on the development of this type of compact atomic clock is presented. To address the low atom numbers obtained in small cold-atom sources, experiments were performed in which an atomic beam was decelerated with bichromatic stimulated laser forces and loaded into a mm-scale magneto-optical trap, increasing the atom number by a factor of 12.5. A CACPT clock using the high-contrast lin||lin optical interrogation technique was developed and achieved a stability of 7 x 10-13 after one hour of integration. Doppler shifts in the clock are explained using a simple kinematic model and canceled by interrogating the atoms with a counter-propagating CPT configuration. Finally, a thorough characterization of the AC-stark effect in lin||lin CPT was performed. Observed shifts are explained in terms of contributions from coherent CPT-generating couplings and population transfer effects caused by optical pumping from incoherent light. Measurements are compared with existing and new theoretical treatments, and a laser configuration is identified that reduces clock drift from light shifts to less than 10-14 for the current system.

  4. Universal bosonic tetramers of dimer-atom-atom structure

    OpenAIRE

    Deltuva, A.

    2012-01-01

    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  5. Double-well atom trap for fluorescence detection at the Heisenberg limit

    Science.gov (United States)

    Stroescu, Ion; Hume, David B.; Oberthaler, Markus K.

    2015-01-01

    We experimentally demonstrate an atom number detector capable of simultaneous detection of two mesoscopic ensembles with single-atom resolution. Such a sensitivity is a prerequisite for quantum metrology at a precision approaching the Heisenberg limit. Our system is based on fluorescence detection of atoms in a hybrid trap in which a dipole barrier divides a magneto-optical trap into two separated wells. We introduce a noise model describing the various sources contributing to the measurement error and report a limit of up to 500 atoms for single-atom resolution in the atom number difference.

  6. Observation of Multiple Thresholds in the Many-Atom Cavity QED Microlaser

    CERN Document Server

    Fang-Yen, C; Ha, S; Choi, W; An, K; Dasari, R R; Feld, M S

    2004-01-01

    We report the observation of multiple laser thresholds in the many-atom cavity QED microlaser. Traveling-wave coupling and a supersonic atom beam are used to create a well-defined atom-cavity interaction. Multiple thresholds are observed as jumps in photon number due to oscillatory gain. Although the number of intra-cavity atoms is large, up to N~1000, the dynamics of the microlaser agree with a single atom theory. This agreement is supported by quantum trajectory simulations of a many-atom microlaser and a semiclassical microlaser theory. We discuss the relation of the microlaser with the micromaser and conventional lasers.

  7. Coherence of a squeezed sodium atom laser generated from Raman output coupling

    Institute of Scientific and Technical Information of China (English)

    Huiyong He; Chunjia Huang

    2009-01-01

    The coherence of a squeezed sodium atom laser generated from a Raman output coupler,in which the sodium atoms in Bose-Einstein condensate (BEC) intcract with two light beams consisting of a weaker squeezed coherent probe light and a stronger classical coupling light,is investigated.The results show that in the case of a large mean number of BEC atoms and a weaker probe light field,the atom laser is antibunching,and this atom laser is second-order coherent if the number of BEC atoms in traps is large enough.

  8. Resonator-Aided Single-Atom Detection on a Microfabricated Chip

    OpenAIRE

    Teper, Igor; Lin, Yu-Ju; Vuletic, Vladan

    2006-01-01

    We use an optical cavity to detect single atoms magnetically trapped on an atom chip. We implement the detection using both fluorescence into the cavity and reduction in cavity transmission due to the presence of atoms. In fluorescence, we register 2.0(2) photon counts per atom, which allows us to detect single atoms with 75% efficiency in 250 microseconds. In absorption, we measure transmission attenuation of 3.3(3)% per atom, which allows us to count small numbers of atoms with a resolution...

  9. Experimental Research of Spontaneous Evolution from Ultracold Rydberg Atoms to Plasma

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lin-Jie; FENG Zhi-Gang; LI An-Ling; ZHAO Jian-Ming; LI Chang-Yong; JIA Suo-Tang

    2008-01-01

    @@ The spontaneous evolution from ultracold Rydberg atoms to plasma is investigated in a caesium MOT by using the method of field ionization. The plasma transferred from atoms in different Rydberg states (n = 22-32) are obtained experimentally. Dependence of the threshold time of evolving to plasma and the threshold number of initial Rydberg atoms on the principal quantum number of initial Rydberg states is studied. The experimental results are in agreement with hot-cold Rydberg-Rydberg atom collision ionization theory.

  10. Theory and applications of atomic and ionic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Mitroy, J [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Safronova, M S [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Clark, Charles W, E-mail: jxm107@rsphysse.anu.edu.a, E-mail: msafrono@udel.ed, E-mail: charles.clark@nist.go [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, MD 20899-8410 (United States)

    2010-10-28

    Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wavefunctions, interferometry with atom beams and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards. (topical review)

  11. Single-atom spintronics

    Institute of Scientific and Technical Information of China (English)

    Susan Z. HUA; Matthew R. SULLIVAN; Jason N. ARMSTRONG

    2006-01-01

    Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition,stepwise or quantum magnetoresistance loops are observed,resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve,i.e.,a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as 'single-atom spintronics'. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided,the requisite hallmarks of artefact-free magnetoresistance is established across a QPC - stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.

  12. Numbers Defy the Law of Large Numbers

    Science.gov (United States)

    Falk, Ruma; Lann, Avital Lavie

    2015-01-01

    As the number of independent tosses of a fair coin grows, the rates of heads and tails tend to equality. This is misinterpreted by many students as being true also for the absolute numbers of the two outcomes, which, conversely, depart unboundedly from each other in the process. Eradicating that misconception, as by coin-tossing experiments,…

  13. Problems with Accurate Atomic Lfetime Measurements of Multiply Charged Ions

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2009-02-19

    A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain cautious about the systematic errors of experimental techniques.

  14. Project Physics Tests 5, Models of the Atom.

    Science.gov (United States)

    Harvard Univ., Cambridge, MA. Harvard Project Physics.

    Test items relating to Project Physics Unit 5 are presented in this booklet. Included are 70 multiple-choice and 23 problem-and-essay questions. Concepts of atomic model are examined on aspects of relativistic corrections, electron emission, photoelectric effects, Compton effect, quantum theories, electrolysis experiments, atomic number and mass,…

  15. Teleportation of atomic states with a weak coherent cavity field

    Institute of Scientific and Technical Information of China (English)

    Zheng Shi-Biao

    2005-01-01

    A scheme is proposed for the teleportation of an unknown atomic state. The scheme is based on the resonant interaction of atoms with a coherent cavity field. The mean photon-number of the cavity field is much smaller than one and thus the cavity decay can be effectively suppressed. Another adwntage of the scheme is that only one cavity is required.

  16. Quantum magnetism through atomic assembly

    NARCIS (Netherlands)

    Spinelli, A.

    2015-01-01

    This thesis presents an experimental study of magnetic structures, composed of only a few atoms. Those structures are first built atom-by-atom and then locally probed, both with a low-temperature STM. The technique that we use to assemble them is vertical atom manipulation, while to study their phy

  17. Parameterizing by the Number of Numbers

    CERN Document Server

    Fellows, Michael R; Rosamond, Frances A

    2010-01-01

    The usefulness of parameterized algorithmics has often depended on what Niedermeier has called, "the art of problem parameterization". In this paper we introduce and explore a novel but general form of parameterization: the number of numbers. Several classic numerical problems, such as Subset Sum, Partition, 3-Partition, Numerical 3-Dimensional Matching, and Numerical Matching with Target Sums, have multisets of integers as input. We initiate the study of parameterizing these problems by the number of distinct integers in the input. We rely on an FPT result for ILPF to show that all the above-mentioned problems are fixed-parameter tractable when parameterized in this way. In various applied settings, problem inputs often consist in part of multisets of integers or multisets of weighted objects (such as edges in a graph, or jobs to be scheduled). Such number-of-numbers parameterized problems often reduce to subproblems about transition systems of various kinds, parameterized by the size of the system descripti...

  18. Cavity QED by the Numbers

    Science.gov (United States)

    Kimble, H. J.; Boca, A.; Boozer, A. D.; Bowen, W. P.; Buck, J. R.; Chou, C. W.; Duan, L.-M.; Kuzmich, A.; McKeever, J.

    2004-12-01

    Observations of cooling and trapping of N = 1,2,3,... atoms inside a small optical cavity are described. The atom-cavity system operates in a regime of strong coupling for which single photons are sufficient to saturate the atomic response. New theoretical protocols for the efficient engineering of multi-atom entanglement within the setting of cavity QED are described. By trapping a single atom within the cavity mode, a one-atom laser is experimentally realized in a regime of strong coupling. Beyond the setting of cavity QED, quantum correlations have been observed for photon pairs emitted from an atomic ensemble and with a programmable time offset.

  19. Asymmetric sequential Landau-Zener dynamics of Bose condensed atoms in a cavity

    CERN Document Server

    Huang, Jiahao; Qin, Xizhou; Zhong, Honghua; Lee, Chaohong

    2016-01-01

    We explore the asymmetric sequential Landau-Zener (LZ) dynamics in an ensemble of interacting Bose condensed two-level atoms coupled with a cavity field. Assuming the couplings between all atoms and the cavity field are identical, the interplay between atom-atom interaction and detuning may lead to a series of LZ transitions. Unlike the conventional sequential LZ transitions, which are symmetric to the zero detuning, the LZ transitions of Bose condensed atoms in a cavity field are asymmetric and sensitively depend on the photon number distribution of the cavity. In LZ processes involving single excitation numbers, both the variance of the relative atom number and the step slope of the sequential population ladder are asymmetric, and the asymmetry become more significant for smaller excitation numbers. Furthermore, in LZ processes involving multiple excitation numbers, there may appear asymmetric population ladders with decreasing step heights. During a dynamical LZ process, due to the atom-cavity coupling, th...

  20. Sampling the Hydrogen Atom

    Directory of Open Access Journals (Sweden)

    Graves N.

    2013-01-01

    Full Text Available A model is proposed for the hydrogen atom in which the electron is an objectively real particle orbiting at very near to light speed. The model is based on the postulate that certain velocity terms associated with orbiting bodies can be considered as being af- fected by relativity. This leads to a model for the atom in which the stable electron orbits are associated with orbital velocities where Gamma is n /α , leading to the idea that it is Gamma that is quantized and not angular momentum as in the Bohr and other models. The model provides a mechanism which leads to quantization of energy levels within the atom and also provides a simple mechanical explanation for the Fine Struc- ture Constant. The mechanism is closely associated with the Sampling theorem and the related phenomenon of aliasing developed in the mid-20th century by engineers at Bell labs.

  1. Number words and number symbols a cultural history of numbers

    CERN Document Server

    Menninger, Karl

    1992-01-01

    Classic study discusses number sequence and language and explores written numerals and computations in many cultures. "The historian of mathematics will find much to interest him here both in the contents and viewpoint, while the casual reader is likely to be intrigued by the author's superior narrative ability.

  2. 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

  3. Hirshfeld atom refinement

    Directory of Open Access Journals (Sweden)

    Silvia C. Capelli

    2014-09-01

    Full Text Available 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 Å2 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.

  4. 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.

  5. Atoms in Agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, Thomas S. [University of Tennessee

    1965-01-01

    Agriculture benefits from the applications of research. Radioactive techniques have been used to study soils, plants, microbes, insects, farm animals, and new ways to use and preserve foodstuffs. Radioactive atoms are not used directly by farmers but are used in research directed by the U. S. Department of Agriculture and Atomic Energy Commission, by the agricultural experiment stations of the various states, and by numerous public and private research institutions. From such research come improved materials and methods which are used on the farm.

  6. On the number of special numbers

    Indian Academy of Sciences (India)

    KEVSER AKTAS; M RAM MURTY

    2017-06-01

    For lack of a better word, a number is called special if it has mutually distinct exponents in its canonical prime factorizaton for all exponents. Let $V (x)$ be the number of special numbers $\\leq x$. We will prove that there is a constant $c$ > 1 such that $V (x) \\sim \\frac{cx}{log x}$. We will make some remarks on determining the error term at the end. Using the explicit abc conjecture, we will study the existence of 23 consecutive special integers.

  7. Enhanced Magnetic Trap Loading for Atomic Strontium

    OpenAIRE

    Barker, D.S.; Reschovsky, B. J.; Pisenti, N. C.; Campbell, G. K.

    2015-01-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser tuned to the 3P1 to 3S1 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65 % for the bosonic isotopes and up to 30 % for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, int...

  8. Atom Probe Tomography of Nanoscale Electronic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Larson, David J.; Prosa, Ty J.; Perea, Daniel E.; Inoue, Hidekazu; Mangelinck, D.

    2016-01-01

    Atom probe tomography (APT) is a mass spectrometry based on time-of-flight measurements which also concurrently produces 3D spatial information. The reader is referred to any of the other papers in this volume or to the following references for further information 4–8. The current capabilities of APT, such as detecting a low number of dopant atoms in nanoscale devices or segregation at a nanoparticle interface, make this technique an important component in the nanoscale metrology toolbox. In this manuscript, we review some of the applications of APT to nanoscale electronic materials, including transistors and finFETs, silicide contact microstructures, nanowires, and nanoparticles.

  9. Cluster growing process and a sequence of magic numbers

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2003-01-01

    demonstrate that in this way all known global minimum structures of the Lennard-Jones (LJ) clusters can be found. Our method provides an efficient tool for the calculation and analysis of atomic cluster structure. With its use we justify the magic number sequence for the clusters of noble gas atoms......We present a new theoretical framework for modeling the cluster growing process. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system, and absorbing its energy at each step, we find cluster growing paths up to the cluster sizes of more than 100 atoms. We...... and compare it with experimental observations....

  10. INFERNO - A better model of atoms in dense plasmas

    Science.gov (United States)

    Liberman, D. A.

    1982-03-01

    A self-consistent field model of atoms in dense plasmas has been devised and incorporated in a computer program. In the model there is a uniform positive charge distribution with a hole in it and at the center of the hole an atomic nucleus. There are electrons, in both bound and continuum states, in sufficient number to form an electrically neutral system. The Dirac equation is used so that high Z atoms can be dealt with. A finite temperature is assumed, and a mean field (average atom) approximation is used in statistical averages. Applications have been made to equations of states and to photoabsorption.

  11. Dispersive Optical Interface Based on Nanofiber-Trapped Atoms

    CERN Document Server

    Dawkins, S T; Reitz, D; Vetsch, E; Rauschenbeutel, A

    2011-01-01

    We dispersively interface an ensemble of one thousand atoms trapped in the evanescent field surrounding a tapered optical nanofiber. This method relies on the azimuthally-asymmetric coupling of the ensemble with the evanescent field of an off-resonant probe beam, transmitted through the nanofiber. The resulting birefringence and dispersion are significant; we observe a phase shift per atom of $\\sim$\\,1\\,mrad at a detuning of six times the natural linewidth, corresponding to an effective resonant optical density per atom of 2.7\\,%. Moreover, we utilize this strong dispersion to non-destructively determine the number of atoms.

  12. Numbers and Numerals.

    Science.gov (United States)

    Smith, David Eugene; Ginsburg, Jekuthiel

    Counting, naming numbers, numerals, computation, and fractions are the topics covered in this pamphlet. Number lore and interesting number properties are noted; the derivation of some arithmetic terms is briefly discussed. (DT)

  13. Cavity-aided magnetic-resonance microscopy of atoms in optical lattices

    CERN Document Server

    Purdy, Tom P; Brooks, Daniel W C; Botter, Thierry; Stamper-Kurn, Dan M

    2010-01-01

    Magnetic resonance imaging (MRI) is a powerful technique for investigating the microscopic properties and dynamics of physical systems. In this work we demonstrate state-sensitive MRI of ultracold atoms in an optical lattice. Single-shot spatial resolution is 120 nm, well below the lattice spacing, and number sensitivity is +/-2.4 for 150 atoms on a single site, well below Poissonian atom-number fluctuations. We achieve this by combining high-spatial-resolution control over the atomic spin using an atom chip, together with nearly quantum-limited spin measurement, obtained by dispersively coupling the atoms to light in a high-finesse optical cavity. The MRI is minimally disruptive of the atoms' internal state, preserving the magnetisation of the gas for subsequent experiments. Using this technique, we observe the nonequilibrium transport dynamics of the atoms among individual lattice sites. We see the atom cloud initially expand ballistically, followed by the onset of interaction-inhibited transport.

  14. Those fascinating numbers

    CERN Document Server

    Koninck, Jean-Marie De

    2009-01-01

    Who would have thought that listing the positive integers along with their most remarkable properties could end up being such an engaging and stimulating adventure? The author uses this approach to explore elementary and advanced topics in classical number theory. A large variety of numbers are contemplated: Fermat numbers, Mersenne primes, powerful numbers, sublime numbers, Wieferich primes, insolite numbers, Sastry numbers, voracious numbers, to name only a few. The author also presents short proofs of miscellaneous results and constantly challenges the reader with a variety of old and new n

  15. Imaging and dynamics of light atoms and molecules on graphene.

    Science.gov (United States)

    Meyer, Jannik C; Girit, C O; Crommie, M F; Zettl, A

    2008-07-17

    Observing the individual building blocks of matter is one of the primary goals of microscopy. The invention of the scanning tunnelling microscope revolutionized experimental surface science in that atomic-scale features on a solid-state surface could finally be readily imaged. However, scanning tunnelling microscopy has limited applicability due to restrictions in, for example, sample conductivity, cleanliness, and data acquisition rate. An older microscopy technique, that of transmission electron microscopy (TEM), has benefited tremendously in recent years from subtle instrumentation advances, and individual heavy (high-atomic-number) atoms can now be detected by TEM even when embedded within a semiconductor material. But detecting an individual low-atomic-number atom, for example carbon or even hydrogen, is still extremely challenging, if not impossible, via conventional TEM owing to the very low contrast of light elements. Here we demonstrate a means to observe, by conventional TEM, even the smallest atoms and molecules: on a clean single-layer graphene membrane, adsorbates such as atomic hydrogen and carbon can be seen as if they were suspended in free space. We directly image such individual adatoms, along with carbon chains and vacancies, and investigate their dynamics in real time. These techniques open a way to reveal dynamics of more complex chemical reactions or identify the atomic-scale structure of unknown adsorbates. In addition, the study of atomic-scale defects in graphene may provide insights for nanoelectronic applications of this interesting material.

  16. Atoms, molecules and optical physics

    CERN Document Server

    Hertel, Ingolf V

    2015-01-01

    This is the first volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 1 provides the canonical knowledge in atomic physics together with basics of modern spectroscopy. Starting from the fundamentals of quantum physics, the reader is familiarized in well structured chapters step by step with the most important phenomena, models and measuring techniques. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginner...

  17. Atomic physics and reality

    CERN Multimedia

    1985-01-01

    An account of the long standing debate between Niels Bohr and Albert Einstein regarding the validity of the quantum mechanical description of atomic phenomena.With physicts, John Wheeler (Texas), John Bell (CERN), David Rohm (London), Abner Shimony (Boston), Alain Aspect (Paris)

  18. Energy from the Atom.

    Science.gov (United States)

    Smith, Patricia L.

    This curriculum guide was written to supplement fifth and sixth grade science units on matter and energy. It was designed to provide more in-depth material on the atom. The first part, "Teacher Guide," contains background information, biographical sketches of persons in the history of nuclear energy, vocabulary, answer sheets, management sheets…

  19. Atomically Traceable Nanostructure Fabrication.

    Science.gov (United States)

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-07-17

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

  20. Chiral atomically thin films

    Science.gov (United States)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  1. Atomic and Molecular Processes

    Science.gov (United States)

    1980-06-25

    The topics investigated experimentally and theoretically by the Pittsburgh Atomic Sciences Institute with applications to high power laser development and atmospheric IR backgrounds are enumerated. Reports containing the detailed scientific progress in these studies are cited. Finally, a list of the journal articles describing the results of the programs, with full references, is given.

  2. Single-Atom Electrocatalysts.

    Science.gov (United States)

    Zhu, Chengzhou; Fu, Shaofang; Shi, Qiurong; Du, Dan; Lin, Yuehe

    2017-05-23

    Recent years have witnessed the increasing production of the sustainable and renewable energy. The limitations of electrochemical performances are closely associated with the search for highly efficient electrocatalysts with more rational control of size, shape, composition and structure. Specifically, the rapidly emerging studies on single-atom catalysts (SACs) have sparked new interests in electrocatalysis because of the unique properties such as high catalytic activity, selectivity and 100% atom utilization. In this review, we introduce the innovative synthesis and advanced characterizations of SACs and primarily focus on their electrochemical applications in oxygen reduction/evolution reaction, hydrogen evolution reaction, hydrocarbon conversion reactions for fuel cells (methanol, ethanol and formic acid electrooxidation) and other related fields. Significantly, this unique single atom-depended electrocatalytic performance together with the underlying mechanism will also be discussed. Furthermore, future research directions and challenges are proposed to further realize the ultimate goal of tailoring single-atoms for electrochemical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 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.

  4. Atomism, Pragmatism, Holism.

    Science.gov (United States)

    Miller, John P.

    1986-01-01

    Examines three world views influencing curriculum development--atomism (underpinning competency-based education), pragmatism (promoting inquiry-based approaches), amd holism (associated with confluent or Waldorf education). Holism embodies the perennial philosophy and attempts to integrate cognitive, affective, and transpersonal dimensions,…

  5. Experiments with Ξ- atoms

    Science.gov (United States)

    Batty, C. J.; Friedman, E.; Gal, A.

    1999-01-01

    Experiments with Ξ- atoms are proposed in order to study the nuclear interaction of Ξ hyperons. The production of Ξ- in the (K-,K+) reaction, the Ξ- stopping in matter, and its atomic cascade are incorporated within a realistic evaluation of the results expected for Ξ- x-ray spectra across the periodic table, using an assumed Ξ-nucleus optical potential Vopt. Several optimal targets for measuring the strong-interaction shift and width of the x-ray transition to the ``last'' atomic level observed are singled out: F, Cl, I, and Pb. The sensitivity of these observables to the parameters of Vopt is considered. The relevance of such experiments is discussed in the context of strangeness -2 nuclear physics and multistrange nuclear matter. Finally, with particular reference to searches for the H dibaryon, the properties of Ξ-d atoms are also discussed. The role of Stark mixing and its effect on S and P state capture of Ξ- by the deuteron together with estimates of the resulting probability for producing the H dibaryon are considered in detail.

  6. 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.)

  7. “Hard probes” of strongly-interacting atomic gases

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Yusuke [Los Alamos National Laboratory

    2012-06-18

    We investigate properties of an energetic atom propagating through strongly interacting atomic gases. The operator product expansion is used to systematically compute a quasiparticle energy and its scattering rate both in a spin-1/2 Fermi gas and in a spinless Bose gas. Reasonable agreement with recent quantum Monte Carlo simulations even at a relatively small momentum k/kF > 1.5 indicates that our large-momentum expansions are valid in a wide range of momentum. We also study a differential scattering rate when a probe atom is shot into atomic gases. Because the number density and current density of the target atomic gas contribute to the forward scattering only, its contact density (measure of short-range pair correlation) gives the leading contribution to the backward scattering. Therefore, such an experiment can be used to measure the contact density and thus provides a new local probe of strongly interacting atomic gases.

  8. Simultaneous magneto-optical trapping of lithium and ytterbium atoms towards production of ultracold polar molecules

    CERN Document Server

    Okano, M; Muramatsu, M; Doi, K; Uetake, S; Takasu, Y; Takahashi, Y

    2009-01-01

    We have successfully implemented the first simultaneous magneto-optical trapping (MOT) of lithium ($^6$Li) and ytterbium ($^{174}$Yb) atoms, towards production of ultracold polar molecules of LiYb. For this purpose, we developed the dual atomic oven which contains both atomic species as an atom source and successfully observed the spectra of the Li and Yb atoms in the atomic beams from the dual atomic oven. We constructed the vacuum chamber including the glass cell with the windows made of zinc selenium (ZnSe) for the CO$_2$ lasers, which are the useful light sources of optical trapping for evaporative and sympathetic cooling. Typical atom numbers and temperatures in the compressed MOT are 7$\\times10^3$ atoms, 640 $\\mu$K for $^6$Li, 7$\\times10^4$ atoms and 60 $\\mu$K for $^{174}$Yb, respectively.

  9. Extracting Atoms on Demand with Lasers

    CERN Document Server

    Mohring, B; Haug, F; Morigi, G; Schleich, W P; Raizen, M G; Mohring, Bernd; Bienert, Marc; Haug, Florian; Morigi, Giovanna; Schleich, Wolfgang P.; Raizen, Mark G.

    2004-01-01

    We propose a scheme that allows to coherently extract cold atoms from a reservoir in a deterministic way. The transfer is achieved by means of radiation pulses coupling two atomic states which are object to different trapping conditions. A particular realization is proposed, where one state has zero magnetic moment and is confined by a dipole trap, whereas the other state with non-vanishing magnetic moment is confined by a steep microtrap potential. We show that in this setup a predetermined number of atoms can be transferred from a reservoir, a Bose-Einstein condensate, into the collective quantum state of the steep trap with high efficiency in the parameter regime of present experiments.

  10. Realization of Green MOT for Ytterbium Atoms

    Institute of Scientific and Technical Information of China (English)

    ZHAO Peng-Yi; XIONG Zhuan-Xian; LONG Yun; HE Ling-Xiang; L(U) Bao-Long

    2009-01-01

    We report the experimental realization of a magneto-optical trap (MOT) of 174Yb atoms operating on the 1S0-3p1 intercombination transition at 555.8 nm.The green MOT is loaded by a Zeeman-slowed atomic beam.In order to increase the capture velocity of the MOT,we use the trapping laser beams consisting of five discrete frequency components obtained by modulating the laser light through an electro-optic modulator.The trapped atomic number of the 174 Yb isotope is about 6.2×105,and the temperature of the cold atowic cloud is estimated to be about 100 μK.The success of the green MOT is an important step towards the goad of an ytterbium optical dock.

  11. Enhanced Magnetic Trap Loading for Atomic Strontium

    CERN Document Server

    Barker, D S; Pisenti, N C; Campbell, G K

    2015-01-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser tuned to the 3P1 to 3S1 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65 % for the bosonic isotopes and up to 30 % for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  12. Enhanced magnetic trap loading for atomic strontium

    Science.gov (United States)

    Barker, D. S.; Reschovsky, B. J.; Pisenti, N. C.; Campbell, G. K.

    2015-10-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a magneto-optical trap. This is achieved by adding a depumping laser tuned to the P31→S31 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65% for the bosonic isotopes and up to 30% for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  13. Mie resonances in inhomogeneous atomic clouds

    CERN Document Server

    Bachelard, Romain; Kaiser, Robin; Piovella, Nicola

    2011-01-01

    Despite the quantum nature of the process, collective scattering by dense cold samples of two-level atoms can be interpreted classically describing the sample as a macroscopic object with a complex refractive index. We demonstrate that Mie resonances can be easily observable in the cooperative scattering by tuning the frequency of the incident laser field or the atomic number. The solution of the scattering problem is obtained for spherical atomic clouds who have the parabolic density characteristic of BECs, and the cooperative radiation pressure force calculated exhibits resonances in the cloud displacement for dense clouds. Reminescent to uniform clouds which show a complex structure of narrow peaks, these densities show resonances, yet under the form of quite regular and contrasted oscillations.

  14. Structure and properties of atomic nanoclusters

    CERN Document Server

    Alonso, Julio A

    2005-01-01

    Atomic clusters are the bridge between molecules and the bulk matter. Following two key experiments - the observation of electronic shells in metallic clusters and the discovery of the C60 fullerence - the field of atomic clusters has experienced a rapid growth, and is now considered a mature field. The electrons of the cluster are confined to a small volume, hence, quantum effects are manifested on many properties of the clusters. Another interesting feature is that the properties often change in a non-smooth way as the number of atoms in the cluster increases. This book provides an updated overview of the field, and presents a detailed description of the structure and electronic properties of different types of clusters: Van der Waals clusters, metallic clusters, clusters of ionic materials and network clusters. The assembling of clusters is also considered, since specially stable clusters are expected to play a role in the future design and synthesis of new materials.

  15. Introduction to number theory

    CERN Document Server

    Vazzana, Anthony; Garth, David

    2007-01-01

    One of the oldest branches of mathematics, number theory is a vast field devoted to studying the properties of whole numbers. Offering a flexible format for a one- or two-semester course, Introduction to Number Theory uses worked examples, numerous exercises, and two popular software packages to describe a diverse array of number theory topics.

  16. δ-FIBONACCI NUMBERS

    OpenAIRE

    Damian Slota; Roman Witula

    2009-01-01

    The scope of the paper is the definition and discussion of the polynomial generalizations of the {sc Fibonacci} numbers called here $delta$-{sc Fibonacci} numbers. Many special identities and interesting relations for these new numbers are presented. Also, different connections between $delta$-{sc Fibonacci} numbers and {sc Fibonacci} and {sc Lucas} numbersare proven in this paper.

  17. Are Numbers Gendered?

    Science.gov (United States)

    Wilkie, James E. B.; Bodenhausen, Galen V.

    2012-01-01

    We examined the possibility that nonsocial, highly generic concepts are gendered. Specifically, we investigated the gender connotations of Arabic numerals. Across several experiments, we show that the number 1 and other odd numbers are associated with masculinity, whereas the number 2 and other even numbers are associated with femininity, in ways…

  18. Are Numbers Gendered?

    Science.gov (United States)

    Wilkie, James E. B.; Bodenhausen, Galen V.

    2012-01-01

    We examined the possibility that nonsocial, highly generic concepts are gendered. Specifically, we investigated the gender connotations of Arabic numerals. Across several experiments, we show that the number 1 and other odd numbers are associated with masculinity, whereas the number 2 and other even numbers are associated with femininity, in ways…

  19. Building Numbers from Primes

    Science.gov (United States)

    Burkhart, Jerry

    2009-01-01

    Prime numbers are often described as the "building blocks" of natural numbers. This article shows how the author and his students took this idea literally by using prime factorizations to build numbers with blocks. In this activity, students explore many concepts of number theory, including the relationship between greatest common factors and…

  20. Antimisting kerosene atomization and flammability

    Science.gov (United States)

    Fleeter, R.; Petersen, R. A.; Toaz, R. D.; Jakub, A.; Sarohia, V.

    1982-01-01

    Various parameters found to affect the flammability of antimisting kerosene (Jet A + polymer additive) are investigated. Digital image processing was integrated into a technique for measurement of fuel spray characteristics. This technique was developed to avoid many of the error sources inherent to other spray assessment techniques and was applied to the study of engine fuel nozzle atomization performance with Jet A and antimisting fuel. Aircraft accident fuel spill and ignition dynamics were modeled in a steady state simulator allowing flammability to be measured as a function of airspeed, fuel flow rate, fuel jet Reynolds number and polymer concentration. The digital imaging technique was employed to measure spray characteristics in this simulation and these results were related to flammability test results. Scaling relationships were investigated through correlation of experimental results with characteristic dimensions spanning more than two orders of magnitude.