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Sample records for monovalent ions single

  1. Attraction between like-charged monovalent ions

    Science.gov (United States)

    Zangi, Ronen

    2012-05-01

    Ions with like-charges repel each other with a magnitude given by the Coulomb law. The repulsion is also known to persist in aqueous solutions albeit factored by the medium's dielectric constant. In this paper, we report results from molecular dynamics simulations of alkali halides salt solutions indicating an effective attraction between some of the like-charged monovalent ions. The attraction is observed between anions, as well as between cations, leading to the formation of dimers with lifetimes on the order of few picoseconds. Two mechanisms have been identified to drive this counterintuitive attraction. The first is exhibited by high-charge density ions, such as fluoride, at low salt concentrations, yielding effective attractions with magnitude up to the order of 1-2 kT. In this case, the stronger local electric field generated when the two ions are in contact augments the alignment of neighboring waters toward the ions. This results in a gain of substantial favorable ion-water interaction energy. For fluorides, this interaction constitutes the major change among the different energy components compensating for the anion-anion repulsion, and therefore, rendering like-charge association possible. The second mechanism involves mediation by counterions, the attractions increase with salt concentration and are characterized by small magnitudes. In particular, clusters of ion triplets, in which a counterion is either bridging the two like-charged ions or is paired to only one of them, are formed. Although these two mechanisms may not yield net attractions in many cases, they might still be operational and significant, explaining effective repulsions between like-charged ions with magnitudes much smaller than expected based on continuum electrostatics.

  2. Attraction between like-charged monovalent ions.

    Science.gov (United States)

    Zangi, Ronen

    2012-05-14

    Ions with like-charges repel each other with a magnitude given by the Coulomb law. The repulsion is also known to persist in aqueous solutions albeit factored by the medium's dielectric constant. In this paper, we report results from molecular dynamics simulations of alkali halides salt solutions indicating an effective attraction between some of the like-charged monovalent ions. The attraction is observed between anions, as well as between cations, leading to the formation of dimers with lifetimes on the order of few picoseconds. Two mechanisms have been identified to drive this counterintuitive attraction. The first is exhibited by high-charge density ions, such as fluoride, at low salt concentrations, yielding effective attractions with magnitude up to the order of 1-2 kT. In this case, the stronger local electric field generated when the two ions are in contact augments the alignment of neighboring waters toward the ions. This results in a gain of substantial favorable ion-water interaction energy. For fluorides, this interaction constitutes the major change among the different energy components compensating for the anion-anion repulsion, and therefore, rendering like-charge association possible. The second mechanism involves mediation by counterions, the attractions increase with salt concentration and are characterized by small magnitudes. In particular, clusters of ion triplets, in which a counterion is either bridging the two like-charged ions or is paired to only one of them, are formed. Although these two mechanisms may not yield net attractions in many cases, they might still be operational and significant, explaining effective repulsions between like-charged ions with magnitudes much smaller than expected based on continuum electrostatics.

  3. Dressed counterions: Polyvalent and monovalent ions at charged dielectric interfaces

    Science.gov (United States)

    Kanduč, Matej; Naji, Ali; Forsman, Jan; Podgornik, Rudolf

    2011-07-01

    We investigate the ion distribution and overcharging at charged interfaces with dielectric inhomogeneities in the presence of asymmetric electrolytes containing polyvalent and monovalent ions. We formulate an effective “dressed counterion” approach by integrating out the monovalent salt degrees of freedom and show that it agrees with results of explicit Monte Carlo simulations. We then apply the dressed counterion approach within the framework of the generalized strong-coupling theory, valid for polyvalent ions at low concentrations, which enables an analytical description for salt effects as well as dielectric inhomogeneities in the limit of strong Coulomb interactions. Limitations and applicability of this theory are examined by comparing the results with simulations.

  4. Monovalent metal ions play an essential role in catalysis and intersubunit communication in the tryptophan synthase bienzyme complex.

    Science.gov (United States)

    Woehl, E U; Dunn, M F

    1995-07-25

    This investigation shows that the alpha 2 beta 2 tryptophan synthase bienzyme complex from Salmonella typhimurium is subject to monovalent metal ion activation. The effects of the monovalent metal ions Na+ and K+ were investigated using rapid scanning stopped-flow (RSSF), single-wavelength stopped-flow (SWSF), and steady-state techniques. RSSF measurements of individual steps in the reaction of L-serine and indole to give L-trytophan (the beta-reaction) as well as the reaction of 3-indole-D-glycerol 3'-phosphate (IGP) with L-serine (the alpha beta-reaction) demonstrate that monovalent metal ions such as Na+ and K+ change the distribution of intermediates in both the transient and steady states. Therefore the metal ion effect alters relative ground-state energies and the relative positions of ground- and transition-state energies. The RSSF spectra and SWSF time courses show that the turnover of indole is significantly reduced in the absence of either Na+ or K+. The alpha-aminoacrylate Schiff base species, E(A-A), is in a less active state in the absence of monovalent metal ions. Na+ decreases the steady-state rate of IGP cleavage (the alpha-reaction) to about 30% of the value obtained in the absence of metal ions. Steady-state investigations show that in the absence of monovalent metal ions the alpha- and alpha beta-reactions have the same activity. Na+ binding gives a 30-fold stimulation of the alpha-reaction when the beta-site is in the E(A-A) form.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Predicting 3D Structure, Flexibility, and Stability of RNA Hairpins in Monovalent and Divalent Ion Solutions

    Science.gov (United States)

    Shi, Ya-Zhou; Jin, Lei; Wang, Feng-Hua; Zhu, Xiao-Long; Tan, Zhi-Jie

    2015-01-01

    A full understanding of RNA-mediated biology would require the knowledge of three-dimensional (3D) structures, structural flexibility, and stability of RNAs. To predict RNA 3D structures and stability, we have previously proposed a three-bead coarse-grained predictive model with implicit salt/solvent potentials. In this study, we further develop the model by improving the implicit-salt electrostatic potential and including a sequence-dependent coaxial stacking potential to enable the model to simulate RNA 3D structure folding in divalent/monovalent ion solutions. The model presented here can predict 3D structures of RNA hairpins with bulges/internal loops (RNA hairpins with bulge loops of different lengths at several divalent/monovalent ion conditions. In addition, the model successfully predicts the stability of RNA hairpins with various loops/stems in divalent/monovalent ion solutions. PMID:26682822

  6. Selective removal of arsenic and monovalent ions from brackish water reverse osmosis concentrate.

    Science.gov (United States)

    Xu, Pei; Capito, Marissa; Cath, Tzahi Y

    2013-09-15

    Concentrate disposal and management is a considerable challenge for the implementation of desalination technologies, especially for inland applications where concentrate disposal options are limited. This study has focused on selective removal of arsenic and monovalent ions from brackish groundwater reverse osmosis (RO) concentrate for beneficial use and safe environmental disposal using in situ and pre-formed hydrous ferric oxides/hydroxides adsorption, and electrodialysis (ED) with monovalent permselective membranes. Coagulation with ferric salts is highly efficient at removing arsenic from RO concentrate to meet a drinking water standard of 10 μg/L. The chemical demand for ferric chloride however is much lower than ferric sulfate as coagulant. An alternative method using ferric sludge from surface water treatment plant is demonstrated as an efficient adsorbent to remove arsenic from RO concentrate, providing a promising low cost, "waste treat waste" approach. The monovalent permselective anion exchange membranes exhibit high selectivity in removing monovalent anions over di- and multi-valent anions. The transport of sulfate and phosphate through the anion exchange membranes was negligible over a broad range of electrical current density. However, the transport of divalent cations such as calcium and magnesium increases through monovalent permselective cation exchange membranes with increasing current density. Higher overall salt concentration reduction is achieved around limiting current density while higher normalized salt removal rate in terms of mass of salt per membrane area and applied energy is attained at lower current density because the energy unitization efficiency decreases at higher current density.

  7. Extraction mechanism of monovalent ion-pairs by polyurethane foams.

    Science.gov (United States)

    Fong, P; Chow, A

    1992-07-01

    The extractability sequence of K(+) approximately Rb(+) > Cs(+) > Na(+) > Li(+) for the extraction with polyether foam suggests that the cation chelation mechanism might be operative. However, the same order was obtained for the extraction with 100% polypropylene oxide polyether foam which does not normally adopt a helical structure to form oxygen-rich cavities as easily or as effectively as polyethylene oxide to accommodate alkali metal ions. This result indicates that a hole-size/cation-diameter relationship may not be required for the high extraction of K(+). The extraction of alkali metal DPAs and hydroxides from methanol demonstrates the importance of the solvent effect. It indicates that the water-structure enforced ion-pairing (WSEIP) is the driving force for extraction of the ion-pairs. The extraction mechanism for ionic species can be described as an ion-pair extraction process. The overall effect of ion-pair formation in water and interaction of the extracted ions with foam appears to determine the extractability of the ions of the extractable ion-pair.

  8. Monovalent ions control proliferation of Ehrlich Lettre ascites cells

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjaer; Preisler, Sarah; Pedersen, Stine Helene Falsig

    2010-01-01

    of Ehrlich Lettre ascites (ELA) cells. We measured the intracellular concentration of each ion in G(0), G(1), and S phases of the cell cycle following synchronization by serum starvation and release. We show that intracellular concentrations and content of Na+ and Cl(-) were reduced in the G(0)-G(1) phase...

  9. Mechanism of interaction of monovalent ions with phosphatidylcholine lipid membranes.

    Science.gov (United States)

    Vácha, Robert; Jurkiewicz, Piotr; Petrov, Michal; Berkowitz, Max L; Böckmann, Rainer A; Barucha-Kraszewska, Justyna; Hof, Martin; Jungwirth, Pavel

    2010-07-29

    Interactions of different anions with phospholipid membranes in aqueous salt solutions were investigated by molecular dynamics simulations and fluorescence solvent relaxation measurements. Both approaches indicate that the anion-membrane interaction increases with the size and softness of the anion. Calculations show that iodide exhibits a genuine affinity for the membrane, which is due to its pairing with the choline group and its propensity for the nonpolar region of the acyl chains, the latter being enhanced in polarizable calculations showing that the iodide number density profile is expanded toward the glycerol level. Solvent relaxation measurements using Laurdan confirm the influence of large soft ions on the membrane organization at the glycerol level. In contrast, chloride exhibits a peak at the membrane surface only in the presence of a surface-attracted cation, such as sodium but not potassium, suggesting that this behavior is merely a counterion effect.

  10. Predicting 3D structure, flexibility and stability of RNA hairpins in monovalent and divalent ion solutions

    CERN Document Server

    Shi, Ya-Zhou; Wang, Feng-Hua; Zhu, Xiao-Long; Tan, Zhi-Jie

    2015-01-01

    A full understanding of RNA-mediated biology would require the knowledge of three-dimensional (3D) structures, structural flexibility and stability of RNAs. To predict RNA 3D structures and stability, we have previously proposed a three-bead coarse-grained predictive model with implicit salt/solvent potentials. In this study, we will further develop the model by improving the implicit-salt electrostatic potential and involving a sequence-dependent coaxial stacking potential to enable the model to simulate RNA 3D structure folding in divalent/monovalent ion solutions. As compared with the experimental data, the present model can predict 3D structures of RNA hairpins with bulge/internal loops (<77nt) from their sequences at the corresponding experimental ion conditions with an overall improved accuracy, and the model also makes reliable predictions for the flexibility of RNA hairpins with bulge loops of different length at extensive divalent/monovalent ion conditions. In addition, the model successfully pred...

  11. Aqueous batteries based on mixed monovalence metal ions: a new battery family.

    Science.gov (United States)

    Chen, Liang; Zhang, Leyuan; Zhou, Xufeng; Liu, Zhaoping

    2014-08-01

    As existing battery technologies struggle to meet the requirements for widespread use in the field of large-scale energy storage, new concepts are urgently needed to build batteries with high energy density, low cost, and good safety. Here, we demonstrate two new aqueous batteries based on two monovalence metal ions (Li(+) /K(+) and Na(+) /K(+) ) as charge-transfer ions, Ni1 Zn1 HCF/TiP2 O7 and Ni1 Zn1 HCF/NaTi2 (PO4 )3 . These new batteries are unlike the conventional "rocking-chair" aqueous metal-ion batteries based on the migration of one type of shuttle ion between cathode and anode. They can deliver specific energy of 46 Wh kg(-1) and 53 Wh kg(-1) based on the total mass of active materials; this is superior to current aqueous battery systems based on sodium-ion and/or potassium-ion technologies. These two new batteries together with the previously developed Li(+) /Na(+) mixed-ion battery not only constitute a new battery family for energy storage, but also greatly broaden our horizons for battery research.

  12. Single crystal structures of thallium (I) thorium fluorides and crystal chemistry of monovalent tetravalent cation pentafluorides

    Science.gov (United States)

    Oudahmane, Abdelghani; El-Ghozzi, Malika; Jouffret, Laurent; Avignant, Daniel

    2015-12-01

    Two thallium (I) thorium (IV) fluorides, TlTh3F13 and TlThF5 were obtained by solid state synthesis and their crystal structures determined from single crystal X-ray diffraction data recorded at room temperature with an APEX-II CCD diffractometer. TlTh3F13 is orthorhombic, space group Pmc21, with a=8.1801(2) Å, b=7.4479(2) Å, c=8.6375(2) Å, V=526.24(2) Å3, Z=2 and TlThF5 is monoclinic, space group P21/n, with a=8.1128(5) Å, b=7.2250(4) Å, c=8.8493(6) Å, β=116.683(3)°, V=463.46(5) Å3, Z=4. The structure of TlTh3F13 comprises layers of corner and edge-sharing ThF9 polyhedra further linked by chains of trans connected tricapped trigonal prisms ThF9 through corners and edges. The three dimensional thorium frameworks delimits channels parallel to [0 0 1] where the 11-coordinated Tl+ ions are arranged into double columns located in mirror planes of the structure. TlTh3F13 is isotypic with RbTh3F13, RbU3F13 and with one of the two polymorphs of CsTh3F13. The structure of TlThF5 may be regarded as a layer structure built up from the regular succession of 2∞[ M ‧F5 ] - corrugated layers further held by the Tl+ ions along the [1 0 1 ̅] direction. The layers are built up from edge and corner-sharing thorium polyhedra where each (ThF9)5- monocapped square antiprism is connected to five others by sharing three edges and two corners. TlThF5 is isostructural with β-NH4UF5 and with one of the polymorphs of CsThF5. A comparison of the different structural types of MM‧F5 pentafluorides is presented and a diagram of repartition of their structures is given. From the comparison of the Tl structures with their Rb or Cs homologs, where very similar monovalent cation environments are observed it should be concluded to a stereochemically inactivity of the 6s2 lone pair of Tl(I) in both TlTh3F13 and TlThF5, contrary to what is observed in richer Tl(I) content Tl3ThF7 fluorothorate.

  13. How accurate is Poisson-Boltzmann theory for monovalent ions near highly charged interfaces?

    Science.gov (United States)

    Bu, Wei; Vaknin, David; Travesset, Alex

    2006-06-20

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface. A lipid phosphate (dihexadecyl hydrogen-phosphate) was spread as a monolayer at the air-water interface to control surface charge density. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. Five decades in bulk concentrations are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. The increase of Cs+ concentration modifies the contact value potential, thereby causing proton release. This process effectively modifies surface charge density and enables exploration of ion distributions as a function of effective surface charge-density. The experimentally obtained ion distributions are compared to distributions calculated by Poisson-Boltzmann theory accounting for the variation of surface charge density due to proton release and binding. We also discuss the accuracy of our experimental results in discriminating possible deviations from Poisson-Boltzmann theory.

  14. Differences on the conversion of celestite in solutions bearing monovalent ions under hydrothermal conditions

    Science.gov (United States)

    Rendón-Angeles, J. C.; Pech-Canul, M. I.; López-Cuevas, J.; Matamoros-Veloza, Z.; Yanagisawa, K.

    2006-12-01

    The replacement of SO 42- ions by monovalent ions in mineral SrSO 4 crystals was investigated under hydrothermal conditions by using aqueous solutions bearing F - and OH - ions. Experiments were conducted at various temperatures (150-250 °C) for different reaction intervals (1-96 h), with M-/SO 42- molar ratios of 1, 5 and 10, where M-=F - or OH -. The celestite crystals were completely converted into SrF 2 crystals, at 200 °C using a F -/SO 42- molar ratio=5 for 24 h. The morphology of the converted SrF 2 crystals indicated that the heteroionic conversion proceeded by a pseudomorphic replacement process, because the transformed crystals maintained their original shape and dimensions. In contrast, the SrSO 4 crystals were instantaneously converted into the Sr(OH) 2 phase by a bulk dissolution-recrystallization mechanism, resulting in the formation of large transparent acicular Sr(OH) 2 crystals. The differences on the conversion process are mainly associated with the chemical interaction between the mineral crystal and the hydrothermal fluid. In addition, the chemical stability of the converted phase with low solubility is also essential for the heteroionic conversion to proceed by the pseudomorphic replacement process.

  15. Simultaneous Analysis of Monovalent Anions and Cations with a Sub-Microliter Dead-Volume Flow-Through Potentiometric Detector for Ion Chromatography.

    Science.gov (United States)

    Dumanli, Rukiye; Attar, Azade; Erci, Vildan; Isildak, Ibrahim

    2016-04-01

    A microliter dead-volume flow-through cell as a potentiometric detector is described in this article for sensitive, selective and simultaneous detection of common monovalent anions and cations in single column ion chromatography for the first time. The detection cell consisted of less selective anion- and cation-selective composite membrane electrodes together with a solid-state composite matrix reference electrode. The simultaneous separation and sensitive detection of sodium (Na(+)), potassium (K(+)), ammonium (NH4 (+)), chloride (Cl(-)) and nitrate (NO3 (-)) in a single run was achieved by using 98% 1.5 mM MgSO4 and 2% acetonitrile eluent with a mixed-bed ion-exchange separation column without suppressor column system. The separation and simultaneous detection of the anions and cations were completed in 6 min at the eluent flow-rate of 0.8 mL/min. Detection limits, at S/N = 3, were ranged from 0.2 to 1.0 µM for the anions and 0.3 to 3.0 µM for the cations, respectively. The developed method was successfully applied to the simultaneous determination of monovalent anions and cations in several environmental and biological samples.

  16. Effect of initial ion positions on the interactions of monovalent and divalent ions with a DNA duplex as revealed with atomistic molecular dynamics simulations.

    Science.gov (United States)

    Robbins, Timothy J; Wang, Yongmei

    2013-01-01

    Monovalent (Na(+)) and divalent (Mg(2+)) ion distributions around the Dickerson-Drew dodecamer were studied by atomistic molecular dynamics (MD) simulations with AMBER molecular modeling software. Different initial placements of ions were tried and the resulting effects on the ion distributions around DNA were investigated. For monovalent ions, results were found to be nearly independent of initial cation coordinates. However, Mg(2+) ions demonstrated a strong initial coordinate dependent behavior. While some divalent ions initially placed near the DNA formed essentially permanent direct coordination complexes with electronegative DNA atoms, Mg(2+) ions initially placed further away from the duplex formed a full, nonexchanging, octahedral first solvation shell. These fully solvated cations were still capable of binding with DNA with events lasting up to 20 ns, and in comparison were bound much longer than Na(+) ions. Force field parameters were also investigated with modest and little differences arising from ion (ions94 and ions08) and nucleic acid description (ff99, ff99bsc0, and ff10), respectively. Based on known Mg(2+) ion solvation structure, we conclude that in most cases Mg(2+) ions retain their first solvation shell, making only solvent-mediated contacts with DNA duplex. The proper way to simulate Mg(2+) ions around DNA duplex, therefore, should begin with ions placed in the bulk water.

  17. Pairing preferences of the model mono-valence mono-atomic ions investigated by molecular simulation.

    Science.gov (United States)

    Zhang, Qiang; Zhang, Ruiting; Zhao, Ying; Li, HuanHuan; Gao, Yi Qin; Zhuang, Wei

    2014-05-14

    We carried out a series of potential of mean force calculations to study the pairing preferences of a series of model mono-atomic 1:1 ions with evenly varied sizes. The probabilities of forming the contact ion pair (CIP) and the single water separate ion pair (SIP) were presented in the two-dimensional plots with respect to the ion sizes. The pairing preferences reflected in these plots largely agree with the empirical rule of matching ion sizes in the small and big size regions. In the region that the ion sizes are close to the size of the water molecule; however, a significant deviation from this conventional rule is observed. Our further analysis indicated that this deviation originates from the competition between CIP and the water bridging SIP state. The competition is mainly an enthalpy modulated phenomenon in which the existing of the water bridging plays a significant role.

  18. Influence of competing inorganic cations on the ion exchange equilibrium of the monovalent organic cation metoprolol on natural sediment.

    Science.gov (United States)

    Niedbala, Anne; Schaffer, Mario; Licha, Tobias; Nödler, Karsten; Börnick, Hilmar; Ruppert, Hans; Worch, Eckhard

    2013-02-01

    The aim of this study was to systematically investigate the influence of the mono- and divalent inorganic ions Na(+) and Ca(2+) on the sorption behavior of the monovalent organic cation metoprolol on a natural sandy sediment at pH=7. Isotherms for the beta-blocker metoprolol were obtained by sediment-water batch tests over a wide concentration range (1-100000 μg L(-1)). Concentrations of the competing inorganic ions were varied within freshwater relevant ranges. Data fitted well with the Freundlich sorption model and resulted in very similar Freundlich exponents (n=0.9), indicating slightly non-linear behavior. Results show that the influence of Ca(2+) compared to Na(+) is more pronounced. A logarithmic correlation between the Freundlich coefficient K(Fr) and the concentration or activity of the competing inorganic ions was found allowing the prediction of metoprolol sorption on the investigated sediment at different electrolyte concentrations. Additionally, the organic carbon of the sediment was completely removed for investigating the influence of organic matter on the sorption of metoprolol. The comparison between the experiments with and without organic carbon removal revealed no significant contribution of the organic carbon fraction (0.1%) to the sorption of metoprolol on the in this study investigated sediment. Results of this study will contribute to the development of predictive models for the transport of organic cations in the subsurface.

  19. Interaction of monovalent ions with the water liquid-vapor interface - A molecular dynamics study

    Science.gov (United States)

    Wilson, Michael A.; Pohorille, Andrew

    1991-01-01

    Results of molecular dynamics calculations are presented for a series of ions at infinite dilution near the water liquid-vapor interface. The free energies of ion transfer from the bulk to the interface are discussed, as are the accompanying changes of water structure at the surface and ion mobilities as a function of their proximity to the interface. It is shown that simple dielectric models do not provide an accurate description of ions at the water surface. The results of the study should be useful in the development of better models incorporating the shape and molecular structure of the interface.

  20. Interaction of monovalent ions with the water liquid-vapor interface - A molecular dynamics study

    Science.gov (United States)

    Wilson, Michael A.; Pohorille, Andrew

    1991-01-01

    Results of molecular dynamics calculations are presented for a series of ions at infinite dilution near the water liquid-vapor interface. The free energies of ion transfer from the bulk to the interface are discussed, as are the accompanying changes of water structure at the surface and ion mobilities as a function of their proximity to the interface. It is shown that simple dielectric models do not provide an accurate description of ions at the water surface. The results of the study should be useful in the development of better models incorporating the shape and molecular structure of the interface.

  1. Monovalent Ions and Water Dipoles in Contact with Dipolar Zwitterionic Lipid Headgroups-Theory and MD Simulations

    Directory of Open Access Journals (Sweden)

    Aljaž Velikonja

    2013-01-01

    Full Text Available The lipid bilayer is a basic building block of biological membranes and can be pictured as a barrier separating two compartments filled with electrolyte solution. Artificial planar lipid bilayers are therefore commonly used as model systems to study the physical and electrical properties of the cell membranes in contact with electrolyte solution. Among them the glycerol-based polar phospholipids which have dipolar, but electrically neutral head groups, are most frequently used in formation of artificial lipid bilayers. In this work the electrical properties of the lipid layer composed of zwitterionic lipids with non-zero dipole moments are studied theoretically. In the model, the zwitterionic lipid bilayer is assumed to be in contact with aqueous solution of monovalent salt ions. The orientational ordering of water, resulting in spatial variation of permittivity, is explicitly taken into account. It is shown that due to saturation effect in orientational ordering of water dipoles the relative permittivity in the zwitterionic headgroup region is decreased, while the corresponding electric potential becomes strongly negative. Some of the predictions of the presented mean-field theoretical consideration are critically evaluated using the results of molecular dynamics (MD simulation.

  2. Specificity of the metalloregulator CueR for monovalent metal ions

    DEFF Research Database (Denmark)

    Szunyogh, Dániel; Szokolai, Hajnalka; Thulstrup, Peter Waaben;

    2015-01-01

    (II) , and Hg(II) binding to model systems encompassing the metal-ion-binding loop of CueR from E. coli and V. cholerae. In the presence of Ag(I) , a conserved cysteine residue displays a pKa value for deprotonation of the thiol that is close to the physiological pH value. This property is only observed...

  3. Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells.

    Directory of Open Access Journals (Sweden)

    Igor A Vereninov

    Full Text Available Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1-10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential.

  4. Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells.

    Science.gov (United States)

    Vereninov, Igor A; Yurinskaya, Valentina E; Model, Michael A; Vereninov, Alexey A

    2016-01-01

    Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1-10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential.

  5. Electrical transport and EPR investigations: A comparative study for d.c. conduction mechanism in monovalent and multivalent ions doped polyaniline

    Indian Academy of Sciences (India)

    Suresh Kumar Gupta; Vandna Luthra; Ramadhar Singh

    2012-10-01

    A detailed comparative study of electron paramagnetic resonance (EPR) in conjunction with d.c. electrical conductivity has been undertaken to know about the charge transport mechanism in polyaniline (PANI) doped with monovalent and multivalent protonic acids. This work is in continuation of our previous work for further understanding the conduction mechanism in conducting polymers. The results reveal that the polarons and bipolarons are the main charge carriers formed during doping process and these cause increase in electrical conductivity not only by increase in their concentration but also because of their enhanced mobility due to increased inter-chain transport in polyaniline at high doping levels. EPR line asymmetry having Dysonian line shape for highly doped samples shows a marked deviation of amplitudes / ratio from values close to one to much high values as usually observed in metals, thereby support the idea of high conductivity at higher doping levels. The nature of dopant ions and their doping levels control the charge carriers concentration as well as electrical conductivity of polyaniline. The electrical conductivity has also been studied as a function of temperature to know the thermally assisted transport process of these charge carriers at different doping levels which has been found to follow the Mott’s variable range hopping (VRH) conduction model for all the three dopants used. The charge carriers show a change over from 3D VRH to quasi 1D VRH hopping process for multivalent ions at higher doping levels whereas 1D VRH has been followed by monovalent ion for full doping range. These studies collectively give evidence of inter-chain percolation at higher doping levels causing increase in effective mobility of the charge carriers which mainly seems to govern the electrical conduction behaviour in this system.

  6. The effect of primycin on the intracellular monovalent ion and water contents of rat hepatocytes as revealed by energy dispersive X-ray microanalysis and interference microscopy.

    Science.gov (United States)

    Horváth, I; Nagy, I; Lustyik, G; Váradi, G

    1983-01-01

    Using energy-dispersive X-ray microanalytic and interference microscopic techniques, the intracellular concentration of the monovalent ions (Na+, K+, Cl+) as well as the intracytoplasmic and intracellular water contents were studied in normal and adrenalectomized rat hepatocytes with and without primycin treatment. Although primycin influenced significantly only the intracellular potassium content of the adrenalectomized group, it exerted a marked influence on the intranuclear water content in both the normal and adrenalectomized rats. The intranuclear water content increased significantly in the primycin-treated animals. The conclusion is drawn that the increased level of hydration of the nuclear substances reflects a 'decondensation' of the chromatin which on the other hand, may represent the basis for the various effects of primycin on the induction of certain hepatic enzymes.

  7. Monovalent plasmonic nanoparticles for biological applications

    Science.gov (United States)

    Seo, Daeha; Lee, Hyunjung; Lee, Jung-uk; Haas, Thomas J.; Jun, Young-wook

    2016-03-01

    The multivalent nature of commercial nanoparticle imaging agents and the difficulties associated with producing monovalent nanoparticles challenge their use in biology, where clustering of target biomolecules can perturb dynamics of biomolecular targets. Here, we report production and purification of monovalent gold and silver nanoparticles for their single molecule imaging application. We first synthesized DNA-conjugated 20 nm and 40 nm gold and silver nanoparticles via conventional metal-thiol chemistry, yielding nanoparticles with mixed valency. By employing an anion-exchange high performance liquid chromatography (AE-HPLC) method, we purified monovalent nanoparticles from the mixtures. To allow efficient peak-separation resolution while keeping the excellent colloidal stability of nanoparticles against harsh purification condition (e.g. high NaCl), we optimized surface properties of nanoparticles by modulating surface functional groups. We characterized the monovalent character of the purified nanoparticles by hybridizing two complementary conjugates, forming dimers. Finally, we demonstrate the use of the monovalent plasmonic nanoprobes as single molecule imaging probes by tracking single TrkA receptors diffusing on the cell membrane and compare to monovalent quantum dot probes.

  8. Investigation of water and methanol sorption in monovalent- and multivalent-ion-exchanged nafion membranes using electron spin resonance.

    Science.gov (United States)

    Lawton, Jamie S; Budil, David E

    2009-08-06

    Electron spin resonance (ESR) spectroscopy was used to monitor the local environment of 2,2,6,6-tetramethyl-4-piperidone N-oxide (TEMPONE) spin probe in Li(+), Ca(2+), and Al(3+) ion-exchanged Nafion 117 membranes swollen with mixed methanol/water solvent at varying compositions. The (14)N hyperfine splitting, a(N), which reflects the local polarity of the nitroxide probe, remains nearly steady at higher solvent contents but increases substantially at lower solvent contents, reflecting close contact with the ions. The rotational rate (R) of the probe increased with solvent content, depending strongly on the amount of solvent at low contents but increasing more gradually at higher solvent contents, similar to the behavior of previously measured solvent translation diffusion coefficients. The rotational rate data from water-containing membranes were fitted using the Fujita free-volume diffusion model, which indicated that multivalent ions tend to increase the free volume fraction of the polymer while decreasing that of the solvent phase. Methanol-containing membranes exhibited greater variation with different exchange ions, but the data could not be fit using the free-volume model, suggesting that the assumption of two phases underlying the free-volume model might not apply to this case. The difference in the trends of swelling between water and methanol is consistent with previous results that have indicated different patterns of penetration for the two solvents. The results are interpreted in terms of changes in membrane morphology with higher-valence ions.

  9. Preparation and characterization of monovalent ion selective cation exchange membranes based on sulphonated poly(ether ether ketone)

    NARCIS (Netherlands)

    Balster, J.H.; Krupenko, O.; Krupenko, O.; Punt, Ineke G.M.; Stamatialis, Dimitrios; Wessling, Matthias

    2005-01-01

    This paper analyses the separation properties of various commercial cation exchange membranes (CEMs) and tailor made membranes based on sulphonated poly(ether ether ketone) and poly(ether sulphone) for binary electrolyte solutions containing protons and calcium ions. All membranes are thoroughly

  10. Preparation and characterisation of monovalent ion selective cation exchange membranes based on sulphonated poly(ether ether ketone)

    NARCIS (Netherlands)

    Balster, J.; Krupenko, O.; Punt, I.G.M.; Stamatialis, D.; Wessling, M.

    2005-01-01

    This paper analyses the separation properties of various commercial cation exchange membranes (CEMs) and tailor made membranes based on sulphonated poly(ether ether ketone) and poly(ether sulphone) for binary electrolyte solutions containing protons and calcium ions. All membranes are thoroughly cha

  11. The Mrp system: a giant among monovalent cation/proton antiporters?

    Science.gov (United States)

    Swartz, Talia H; Ikewada, Sayuri; Ishikawa, Osamu; Ito, Masahiro; Krulwich, Terry Ann

    2005-10-01

    Mrp systems are a novel and broadly distributed type of monovalent cation/proton antiporter of bacteria and archaea. Monovalent cation/proton antiporters are membrane transport proteins that catalyze efflux of cytoplasmic sodium, potassium or lithium ions in exchange for external hydrogen ions (protons). Other known monovalent cation antiporters are single gene products, whereas Mrp systems have been proposed to function as hetero-oligomers. A mrp operon typically has six or seven genes encoding hydrophobic proteins all of which are required for optimal Mrp-dependent sodium-resistance. There is little sequence similarity of Mrp proteins to other antiporters but three of these proteins have significant sequence similarity to membrane embedded subunits of ion-translocating electron transport complexes. Mrp antiporters have essential roles in the physiology of alkaliphilic and neutralophilic Bacillus species, nitrogen-fixing Sinorhizobium meliloti and in the pathogen Staphylococcus aureus, although these bacteria contain multiple monovalent cation/proton antiporters. The wide distribution of Mrp systems leads to the anticipation of important roles in an even wider variety of pathogens, extremophiles and environmentally important organisms. Here, the distribution, established physiological roles and catalytic activities of Mrp systems are reviewed, hypotheses regarding their complexity are discussed and major open questions about their function are highlighted.

  12. A monovalent ion-selective cation current activated by noradrenaline in smooth muscle cells of rabbit ear artery.

    Science.gov (United States)

    Wang, Q; Hogg, R C; Large, W A

    1993-04-01

    Membrane currents were recorded with the perforated-patch method with a low-chloride (35 mM) pipette solution in isolated smooth muscle cells of the rabbit ear artery. At a holding potential of -50 mV in potassium-free conditions spontaneous inward single-channel currents were observed and noradrenaline evoked a noisy inward current, which appeared to be comprised of the spontaneous currents. The reversal potential (Vr) of the spontaneous channel and noradrenaline-induced current was not affected in anion-substitution experiments but Vr was altered when external Na+ was replaced with choline or TRIS. The relationship between clamp potential and spontaneous single-channel current amplitude was linear and the mean unitary conductance was 28 pS. Caffeine, which releases calcium from the sarcoplasmic reticulum, and the calcium ionophore ionomycin activated the cation current and also blocked the response to noradrenaline. Spontaneous channel current activity and the noradrenaline-induced current were blocked when external NaCl was replaced with 89 mM CaCl2. The response to noradrenaline was blocked by prazosin but was not affected by yohimbine and therefore the response is mediated by alpha 1-adrenoceptors. It is concluded that in rabbit ear artery smooth muscle cells there is a calcium-activated cation channel of 28 pS conductance, which is relatively impermeable to calcium but can be activated by noradrenaline.

  13. Effects of monovalent cation doping on the structure, microstructure, lattice distortion and magnetic behavior of single crystalline NdMnO3 compounds.

    Science.gov (United States)

    Nandy, Anshuman; Pradhan, S K

    2015-10-21

    Pure and 15 mol% Na, K-doped NdMnO3 compounds with perovskite structures are prepared by sol-gel method. Tiny single crystals are formed after sintering the compounds at 1000 °C. The effect of Na and K doping as well as the effect of sintering temperature on the formation and microstructure of NdMnO3 are studied in detail by the Rietveld refinement technique using X-ray powder diffraction data. Single phase formation and single crystalline growth are also confirmed by high resolution transmission electron microscopy (HRTEM). Bond angles and bond lengths are calculated and shown by 3D diagrams. Monovalent doping induces noticeable changes in the microstructure and yields better structural stability in these compounds. Doping results in the change of Mn-O, Nd-O and Mn-O-Mn bond lengths which in turn reduces the lattice and octahedral distortion in the system along with an increase in the tolerance factor. The magnetic properties of these compounds are also modified as a result of doping. The temperature dependent magnetization results show that the Neel temperature of antiferromagnetic NdMnO3 compound is 67.2 K and the Curie temperatures of ferromagnetic Nd0.85Na0.15MnO3 and Nd0.85K0.15MnO3 compounds are 99.1 K and 98.6 K respectively. Both 15% Na and K doping results in a similar TC in doped NdMnO3 compounds.

  14. Crater formation by single ions, cluster ions and ion "showers"

    CERN Document Server

    Djurabekova, Flyura; Timko, Helga; Nordlund, Kai; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter

    2011-01-01

    The various craters formed by giant objects, macroscopic collisions and nanoscale impacts exhibit an intriguing resemblance in shapes. At the same time, the arc plasma built up in the presence of sufficiently high electric fields at close look causes very similar damage on the surfaces. Although the plasma–wall interaction is far from a single heavy ion impact over dense metal surfaces or the one of a cluster ion, the craters seen on metal surfaces after a plasma discharge make it possible to link this event to the known mechanisms of the crater formations. During the plasma discharge in a high electric field the surface is subject to high fluxes (~1025 cm-2s-1) of ions with roughly equal energies typically of the order of a few keV. To simulate such a process it is possible to use a cloud of ions of the same energy. In the present work we follow the effect of such a flux of ions impinging the surface in the ‘‘shower’’ manner, to find the transition between the different mechanisms of crater formati...

  15. Single ion implantation in semiconductor nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Niepelt, Raphael; Johannes, Andreas; Gnauck, Martin; Slowik, Irma; Geburt, Sebastian; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet, Jena (Germany)

    2011-07-01

    Ion implantation is well established as a standard doping technique for semiconductor nanowires. The concentration of dopant atoms per area is typically determined by total beam current monitoring during the irradiation. However, at extremely low ion fluencies, it is not possible to distinguish the exact number of implanted ions in a nanometer sized structure, as the ions are distributed statistically over the irradiated area that is usually far wider than the nanostructure of interest. In our experiments we implanted electrically contacted semiconductor nanostructures that were connected to a preamplifier/amplifier setup. As with every impinging ion a certain amount of energy is deposited inside the material, one can detect signals directly induced by the ion implantation and the nanostructures themselves can act as a radiation sensor. This leads to a countable and very precisely adjustable ion dose during the implantation down to doping with single ions.

  16. Single Ion Implantation and Deterministic Doping

    Energy Technology Data Exchange (ETDEWEB)

    Schenkel, Thomas

    2010-06-11

    The presence of single atoms, e.g. dopant atoms, in sub-100 nm scale electronic devices can affect the device characteristics, such as the threshold voltage of transistors, or the sub-threshold currents. Fluctuations of the number of dopant atoms thus poses a complication for transistor scaling. In a complementary view, new opportunities emerge when novel functionality can be implemented in devices deterministically doped with single atoms. The grand price of the latter might be a large scale quantum computer, where quantum bits (qubits) are encoded e.g. in the spin states of electrons and nuclei of single dopant atoms in silicon, or in color centers in diamond. Both the possible detrimental effects of dopant fluctuations and single atom device ideas motivate the development of reliable single atom doping techniques which are the subject of this chapter. Single atom doping can be approached with top down and bottom up techniques. Top down refers to the placement of dopant atoms into a more or less structured matrix environment, like a transistor in silicon. Bottom up refers to approaches to introduce single dopant atoms during the growth of the host matrix e.g. by directed self-assembly and scanning probe assisted lithography. Bottom up approaches are discussed in Chapter XYZ. Since the late 1960's, ion implantation has been a widely used technique to introduce dopant atoms into silicon and other materials in order to modify their electronic properties. It works particularly well in silicon since the damage to the crystal lattice that is induced by ion implantation can be repaired by thermal annealing. In addition, the introduced dopant atoms can be incorporated with high efficiency into lattice position in the silicon host crystal which makes them electrically active. This is not the case for e.g. diamond, which makes ion implantation doping to engineer the electrical properties of diamond, especially for n-type doping much harder then for silicon. Ion

  17. Poisson-Helmholtz-Boltzmann model of the electric double layer: analysis of monovalent ionic mixtures.

    Science.gov (United States)

    Bohinc, Klemen; Shrestha, Ahis; Brumen, Milan; May, Sylvio

    2012-03-01

    In the classical mean-field description of the electric double layer, known as the Poisson-Boltzmann model, ions interact exclusively through their Coulomb potential. Ion specificity can arise through solvent-mediated, nonelectrostatic interactions between ions. We employ the Yukawa pair potential to model the presence of nonelectrostatic interactions. The combination of Yukawa and Coulomb potential on the mean-field level leads to the Poisson-Helmholtz-Boltzmann model, which employs two auxiliary potentials: one electrostatic and the other nonelectrostatic. In the present work we apply the Poisson-Helmholtz-Boltzmann model to ionic mixtures, consisting of monovalent cations and anions that exhibit different Yukawa interaction strengths. As a specific example we consider a single charged surface in contact with a symmetric monovalent electrolyte. From the minimization of the mean-field free energy we derive the Poisson-Boltzmann and Helmholtz-Boltzmann equations. These nonlinear equations can be solved analytically in the weak perturbation limit. This together with numerical solutions in the nonlinear regime suggests an intricate interplay between electrostatic and nonelectrostatic interactions. The structure and free energy of the electric double layer depends sensitively on the Yukawa interaction strengths between the different ion types and on the nonelectrostatic interactions of the mobile ions with the surface.

  18. An organometallic single-ion magnet.

    Science.gov (United States)

    Jiang, Shang-Da; Wang, Bing-Wu; Sun, Hao-Ling; Wang, Zhe-Ming; Gao, Song

    2011-04-06

    An organometallic single-ion magnet is synthesized with only 19 non-hydrogen atoms featuring an erbium ion sandwiched by two different aromatic ligands. This molecule displays a butterfly-shaped hysteresis loop at 1.8 K up to even 5 K. Alternating-current (ac) susceptibility measurement reveals the existence of two thermally activated magnetic relaxation processes with the energy barriers as high as 197 and 323 K, respectively.

  19. Monovalent copper-activated oxygenated insulators

    Science.gov (United States)

    Parent, C.; Boutinaud, P.; Flem, G. Le; Moine, B.; Pedrini, C.; Garcia, D.; Faucher, M.

    1994-12-01

    The photoluminescence of monovalent copper in oxygenated insulators has been extensively studied. The spectroscopy and the excited states dynamics of Cu + ions were investigated as a function of the copper concentration and temperature in various glassy and crystallized materials, essentially borates and phosphates. The broad band fluorescences observed in the visible range under UV excitation arise from two main emitting centers: isolated Cu + ions and (Cu +) 2 pairs. The spectroscopic characteristics of isolated Cu + depend strongly on the local structure, whereas those of the copper pairs remain nearly unaltered whatever the host-matrix. Energy diagrams are proposed for both centers, using ab initio LCAO calculations, in connection with structural investigations involving XRD, ND and EXAFS spectroscopies. Borate glasses can be considered as potential laser sources for tunable output in the whole visible range.

  20. Production and targeting of monovalent quantum dots.

    Science.gov (United States)

    Seo, Daeha; Farlow, Justin; Southard, Kade; Jun, Young-Wook; Gartner, Zev J

    2014-10-23

    The multivalent nature of commercial quantum dots (QDs) and the difficulties associated with producing monovalent dots have limited their applications in biology, where clustering and the spatial organization of biomolecules is often the object of study. We describe here a protocol to produce monovalent quantum dots (mQDs) that can be accomplished in most biological research laboratories via a simple mixing of CdSe/ZnS core/shell QDs with phosphorothioate DNA (ptDNA) of defined length. After a single ptDNA strand has wrapped the QD, additional strands are excluded from the surface. Production of mQDs in this manner can be accomplished at small and large scale, with commercial reagents, and in minimal steps. These mQDs can be specifically directed to biological targets by hybridization to a complementary single stranded targeting DNA. We demonstrate the use of these mQDs as imaging probes by labeling SNAP-tagged Notch receptors on live mammalian cells, targeted by mQDs bearing a benzylguanine moiety.

  1. Feedback cooling of a single trapped ion

    CERN Document Server

    Bushev, P; Wilson, A; Dubin, F; Becher, C; Eschner, J; Blatt, R; Steixner, V; Rabl, P; Zoller, P; Bushev, Pavel; Rotter, Daniel; Wilson, Alex; Dubin, Francois; Becher, Christoph; Eschner, Juergen; Blatt, Rainer; Steixner, Viktor; Rabl, Peter; Peter Zoller

    2005-01-01

    Based on a real-time measurement of the motion of a single ion in a Paul trap, we demonstrate its electro-mechanical cooling below the Doppler limit by homodyne feedback control (cold damping). The feedback cooling results are well described by a model based on a quantum mechanical Master Equation.

  2. Radium single-ion optical clock

    NARCIS (Netherlands)

    Versolato, O. O.; Wansbeek, L. W.; Jungmann, K.; Timmermans, R. G. E.; Willmann, L.; Wilschut, H. W.

    2011-01-01

    We explore the potential of the electric quadrupole transitions $7s\\,^2S_{1/2}$ - $6d\\,^2D_{3/2}$, $6d\\,^2D_{5/2}$ in radium isotopes as single-ion optical frequency standards. The frequency shifts of the clock transitions due to external fields and the corresponding uncertainties are calculated.

  3. Multivalent Protein Assembly Using Monovalent Self-Assembling Building Blocks

    Directory of Open Access Journals (Sweden)

    Katja Petkau-Milroy

    2013-10-01

    Full Text Available Discotic molecules, which self-assemble in water into columnar supramolecular polymers, emerged as an alternative platform for the organization of proteins. Here, a monovalent discotic decorated with one single biotin was synthesized to study the self-assembling multivalency of this system in regard to streptavidin. Next to tetravalent streptavidin, monovalent streptavidin was used to study the protein assembly along the supramolecular polymer in detail without the interference of cross-linking. Upon self-assembly of the monovalent biotinylated discotics, multivalent proteins can be assembled along the supramolecular polymer. The concentration of discotics, which influences the length of the final polymers at the same time dictates the amount of assembled proteins.

  4. A single-ion nonlinear mechanical oscillator

    CERN Document Server

    Akerman, Nitzan; Glickamn, Yinnon; Dallal, Yehonatan; Keselman, Anna; Ozeri, Roee

    2010-01-01

    We study the steady state motion of a single trapped ion oscillator driven to the nonlinear regime. Damping is achieved via Doppler laser-cooling. The ion motion is found to be well described by the Duffing oscillator model with an additional nonlinear damping term. We demonstrate a unique ability of tuning both the linear as well as the nonlinear damping coefficients by controlling the cooling laser parameters. Our observations open a way for the investigation of nonlinear dynamics on the quantum-to-classical interface as well as mechanical noise squeezing in laser-cooling dynamics.

  5. Weak interactions in trapped single radium ions

    Energy Technology Data Exchange (ETDEWEB)

    Wansbeek, L.; Willmann, L. [Kernfysisch Versneller Instituut, University of Groningen (Netherlands)

    2007-07-01

    The electroweak theory has been confirmed to great precision in high-energy accelerator experiments. One of the outstanding successful predictions of the theory was the existence of the Z{sup 0} boson, that is mixed with the photon and mediates interactions that do not conserve parity. The mixing angle varies with sca le due to the polarization of the vacuum by particle-antiparticle pairs. This has only poorly been tested. Interference of Z{sup 0} and photon exchange between the electrons and quarks in an atom or ion results in a tiny breakdown of parity selection rules. A high-precision measurement of the electroweak mixing angle at low momentum scales is possible by monitoring quantum jumps in one single trapped Ra ion with precision laser and radiofrequency techniques combined. The proof of principle was recently given in pilot measurements at Seattle with one single Ba ion. A Ra{sup +} experiment can now be envisaged with a precision that, together wit h planned experiments at intermediate energy, can confirm the quantum structure of the electroweak theory over some five orders of magnitude in momentum scale. Such an experiment has been started at the TRI{mu}P facility of the Kernfysisch Versneller Instituut in Groningen, where the needed radioactive Ra isotopes can be produced online. The experiment uses will use a radiofrequency trap and is possible using several all solid state lasers in an elaborate time switching scheme.

  6. Direct observation of the dynamics of single metal ions at the interface with solids in aqueous solutions

    Science.gov (United States)

    Ricci, Maria; Trewby, William; Cafolla, Clodomiro; Voïtchovsky, Kislon

    2017-02-01

    The dynamics of ions adsorbed at the surface of immersed charged solids plays a central role in countless natural and industrial processes such as crystal growth, heterogeneous catalysis, electrochemistry, or biological function. Electrokinetic measurements typically distinguish between a so-called Stern layer of ions and water molecules directly adsorbed on to the solid’s surface, and a diffuse layer of ions further away from the surface. Dynamics within the Stern layer remain poorly understood, largely owing to a lack of in-situ atomic-level insights. Here we follow the dynamics of single Rb+ and H3O+ ions at the surface of mica in water using high-resolution atomic force microscopy with 25 ms resolution. Our results suggest that single hydrated Rb+ions reside τ1 = 104 ± 5 ms at a given location, but this is dependent on the hydration state of the surface which evolves on a slower timescale of τ2 = 610 ± 30 ms depending on H3O+ adsorption. Increasing the liquid’s temperature from 5 °C to 65 °C predictably decreases the apparent glassiness of the interfacial water, but no clear effect on the ions’ dynamics was observed, indicating a diffusion-dominated process. These timescales are remarkably slow for individual monovalent ions and could have important implications for interfacial processes in electrolytes.

  7. Microscopy with a Deterministic Single Ion Source

    CERN Document Server

    Jacob, Georg; Wolf, Sebastian; Ulm, Stefan; Couturier, Luc; Dawkins, Samuel T; Poschinger, Ulrich G; Schmidt-Kaler, Ferdinand; Singer, Kilian

    2015-01-01

    We realize a single particle microscope by using deterministically extracted laser cooled $^{40}$Ca$^+$ ions from a Paul trap as probe particles for transmission imaging. We demonstrate focusing of the ions with a resolution of 5.8$\\;\\pm\\;$1.0$\\,$nm and a minimum two-sample deviation of the beam position of 1.5$\\,$nm in the focal plane. The deterministic source, even when used in combination with an imperfect detector, gives rise to much higher signal to noise ratios as compared with conventional Poissonian sources. Gating of the detector signal by the extraction event suppresses dark counts by 6 orders of magnitude. We implement a Bayes experimental design approach to microscopy in order to maximize the gain in spatial information. We demonstrate this method by determining the position of a 1$\\,\\mu$m circular hole structure to an accuracy of 2.7$\\,$nm using only 579 probe particles.

  8. Single Ion Quantum Lock-In Amplifier

    CERN Document Server

    Kotler, Shlomi; Glickman, Yinnon; Keselman, Anna; Ozeri, Roee

    2011-01-01

    We report on the implementation of a quantum analog to the classical lock-in amplifier. All the lock-in operations: modulation, detection and mixing, are performed via the application of non-commuting quantum operators on the electronic spin state of a single trapped Sr+ ion. We significantly increase its sensitivity to external fields while extending phase coherence by three orders of magnitude, to more than one second. With this technique we measure magnetic fields with sensitivity of 25 pT/sqrt(Hz) and light shifts with an uncertainty below 140 mHz after 1320 seconds of averaging. These sensitivities are limited by quantum projection noise and, to our knowledge, are more than two orders of magnitude better than with other single-spin probe technologies. In fact, our reported sensitivity is sufficient for the measurement of parity non-conservation, as well as the detection of the magnetic field of a single electronic-spin one micrometer from an ion-detector with nanometer resolution. As a first application ...

  9. Single dose vaccination of the ASO3-adjuvanted A(H1N1)pdm09 monovalent vaccine in health care workers elicits homologous and cross-reactive cellular and humoral responses to H1N1 strains.

    Science.gov (United States)

    Lartey, Sarah; Pathirana, Rishi D; Zhou, Fan; Jul-Larsen, Åsne; Montomoli, Emanuele; Wood, John; Cox, Rebecca Jane

    2015-01-01

    Healthcare workers (HCW) were prioritized for vaccination during the 2009 influenza A(H1N1)pdm09 pandemic. We conducted a clinical trial in October 2009 where 237 HCWs were immunized with a AS03-adjuvanted A(H1N1)pdm09 monovalent vaccine. In the current study, we analyzed the homologous and cross-reactive H1N1 humoral responses using prototype vaccine strains dating back to 1977 by the haemagglutinin inhibition (HI), single radial hemolysis SRH), antibody secreting cell (ASC) and memory B cell (MBC) assays. The cellular responses were assessed by interferon-γ (IFN-γ) ELISPOT and by intracellular staining (ICS) for the Th1 cytokines IFN-γ, interleukin-2 (IL-2) and tumor necrosis factor-α (TNF-α). All assays were performed using blood samples obtained prior to (day 0) and 7, 14 and 21 d post-pandemic vaccination, except for ASC (day 7) and ICS (days 0 and 21). Vaccination elicited rapid HI, SRH and ASC responses against A(H1N1)pdm09 which cross reacted with seasonal H1N1 strains. MBC responses were detected against the homologous and seasonal H1N1 strains before vaccination and were boosted 2 weeks post-vaccination. An increase in cellular responses as determined by IFN-γ ELISPOT and ICS were observed 1-3 weeks after vaccination. Collectively, our data show that the AS03-adjuvanted A(H1N1)pdm09 vaccine induced rapid cellular and humoral responses against the vaccine strain and the response cross-reacted against prototype H1N1 strains dating back to 1977.

  10. A singly charged ion source for radioactive {sup 11}C ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K. [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

    2016-02-15

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive {sup 11}C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  11. A singly charged ion source for radioactive 11C ion acceleration

    Science.gov (United States)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K.

    2016-02-01

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  12. Radium single-ion optical clock

    CERN Document Server

    Versolato, O O; Jungmann, K; Timmermans, R G E; Willmann, L; Wilschut, H W

    2011-01-01

    We explore the potential of the electric quadrupole transitions $7s\\,^2S_{1/2}$ - $6d\\,^2D_{3/2}$, $6d\\,^2D_{5/2}$ in radium isotopes as single-ion optical frequency standards. The frequency shifts of the clock transitions due to external fields and the corresponding uncertainties are calculated. Several competitive $^A$Ra$^+$ candidates with $A=$ 223 - 229 are identified. In particular, we show that the transition $7s\\,^2S_{1/2}\\,(F=2,m_F=0)$ - $6d\\,^2D_{3/2}\\,(F=0,m_F=0)$ at 828 nm in $^{223}$Ra$^+$, with no linear Zeeman and electric quadrupole shifts, stands out as a relatively simple case, which could be exploited as a compact, robust, and low-cost atomic clock operating at a fractional frequency uncertainty of $10^{-17}$. With more experimental effort, the $^{223,225,226}$Ra$^+$ clocks could be pushed to a projected performance reaching the $10^{-18}$ level.

  13. Surface nanostructures by single highly charged ions.

    Science.gov (United States)

    Facsko, S; Heller, R; El-Said, A S; Meissl, W; Aumayr, F

    2009-06-03

    It has recently been demonstrated that the impact of individual, slow but highly charged ions on various surfaces can induce surface modifications with nanometer dimensions. Generally, the size of these surface modifications (blisters, hillocks, craters or pits) increases dramatically with the potential energy of the highly charged ion, while the kinetic energy of the projectile ions seems to be of little importance. This paper presents the currently available experimental evidence and theoretical models and discusses the circumstances and conditions under which nanosized features on different surfaces due to the impact of slow highly charged ions can be produced.

  14. Single ion counting with a MCP (microchannel plate) detector

    Energy Technology Data Exchange (ETDEWEB)

    Tawara, Hiroko; Sasaki, Shinichi; Miyajima, Mitsuhiro [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan); Shibamura, Eido

    1996-07-01

    In this study, a single-ion-counting method using alpha-particle-impact ionization of Ar atoms is demonstrated and the preliminary {epsilon}{sub mcp} for Ar ions with incident energies of 3 to 4.7 keV is determined. The single-ion counting by the MCP is aimed to be performed under experimental conditions as follows: (1) A signal from the MCP is reasonably identified as incidence of single Ar-ion. (2) The counting rate of Ar ions is less than 1 s{sup -1}. (3) The incident Ar ions are not focused on a small part of an active area of the MCP, namely, {epsilon}{sub mcp} is determined with respect to the whole active area of the MCP. So far, any absolute detection efficiency has not been reported under these conditions. (J.P.N.)

  15. Ionic force field optimization based on single-ion and ion-pair solvation properties

    CERN Document Server

    Fyta, Maria; Dzubiella, Joachim; Vrbka, Lubos; Netz, Roland R

    2009-01-01

    Molecular dynamics simulations of ionic solutions depend sensitively on the force fields employed for the ions. To resolve the fine differences between ions of the same valence and roughly similar size and in particular to correctly describe ion-specific effects, it is clear that accurate force fields are necessary. In the past, optimization strategies for ionic force fields either considered single-ion properties (such as the solvation free energy at infinite dilution or the ion-water structure) or ion-pair properties (in the form of ion-ion distribution functions). In this paper we investigate strategies to optimize ionic force fields based on single-ion and ion-pair properties simultaneously. To that end, we simulate five different salt solutions, namely CsCl, KCl, NaI, KF, and CsI, at finite ion concentration. The force fields of these ions are systematically varied under the constraint that the single-ion solvation free energy matches the experimental value, which reduces the two-dimensional $\\{\\sigma,\\e...

  16. Exact Quantum Logic Gates with a Single Trapped Cold Ion

    Institute of Scientific and Technical Information of China (English)

    韦联福; 刘世勇; 雷啸霖

    2001-01-01

    We present an alternative scheme to exactly implement one-qubit and two-qubit quantum gates with a single trapped cold ion driven by a travelling laser field. The internal degree of freedom of the ion acts as the target qubit and the control qubit is encoded by two Fock states of the external vibration of the ion. The conditions to realize these operations, including the duration of each applied laser pulse and Lamb-Dicke parameter, are derived. In our scheme neither the auxiliary atomic level nor the Lamb-Dicke approximation is required. The multiquantum transition between the internal and external degrees of freedom of the ion is considered.

  17. Quantitative Single-Ion Irradiation by ASIPP Microbeam

    Institute of Scientific and Technical Information of China (English)

    WANG Xu-Fei; WU Yu; XU Ming-Liang; WU Li-Jun; WANG Shao-Hu; YU Zeng-Liang; CHEN Lian-Yun; HU Zhi-Wen; WANG Xiao-Hua; ZHANG Jun; LI Jun; CHEN Bin; HU Su-Hua; SHI Zhong-Tao

    2004-01-01

    @@ A single-ion microbeam facility has been constructed by the microbeam research group in ASIPP (Institute of Plasma Physics, Chinese Academy of Science). The system was designed to deliver defined numbers of hydrogen ions produced by a van de Graaff accelerator, covering an energy range from 200keV to 3 MeV, into living cells(5 μm-20 μm diameter) growing in culture on thin plastic films. The beam is collimated by a 1- μm inner diameter HPLC (high performance liquid chromatography) capillary, which forms the micron-dimensional beam-line exit.A microbeam collimator, a scintillation ion counting system and a fast beam shutter, which constitute a precise dosage measuring and controlling system, jointly perform quantitative single-ion irradiation. With this facility,we can presently acquire ion-hitting efficiency close to 95%.

  18. Towards the Precision Spectroscopy of a Single Molecular Ion

    Science.gov (United States)

    Lin, Yen-Wei

    This dissertation presents some development of the single molecular ion precision spectroscopy experiment including construction of the project, spectroscopy state readout, and production of ultracold molecules. Such molecular ion spectroscopy aims at testing fundamental physics such as probing the time variation of electron-proton mass ratio. The theories and characterization of ion traps are first discussed along with information regarding building the ion trapping systems. Then, routines in this project such as loading ions, Doppler laser cooling, excessive micromotion compensation, secular motion detection, and fluorescence imaging are deliberated. In the state readout experiment, the coherent motion of a single trapped barium ion resonantly driving by a radiation pressure is studied. By scattering of order only one hundred photons, the radiation pressure is able to seed a laser-cooled ion with a secular oscillation that is detectable by the Doppler velocimetry technique after proper motional amplification. This seeding method provides a mapping between the ion's internal configuration and its secular motion and can be used to read out the spectroscopy results from a single non-fluorescing ion with a partially-closed cycling transition. The work of ultracold molecule production is done with silicon monoxide ions, which has a strong vibration-conserved spontaneous decay branching. Therefore, by optically pumping the rotational cooling transitions in silicon monoxide ions with a broadband radiation, the population can be efficiently driven into the ground rotational state before falling into other manifolds. To avoid the rotational heating transition, the broadband source, derived from a femtosecond pulsed laser, is spectrally filtered using an ultrashort pulse shaper.

  19. A compact source for bunches of singly charged atomic ions

    Science.gov (United States)

    Murböck, T.; Schmidt, S.; Andelkovic, Z.; Birkl, G.; Nörtershäuser, W.; Vogel, M.

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 106 Mg+ ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg+ ions for sympathetic cooling of highly charged ions by laser-cooled 24Mg+.

  20. Localization Spectroscopy of a Single Ion in an Optical Lattice

    DEFF Research Database (Denmark)

    Legrand, Olivier Philippe Alexandre

    2015-01-01

    The work reported in this thesis primarily focuses on studies of the dynamics of a single laser-cooled ion, simultaneously confined in the harmonic potential of a linear Paul trap and a rapidly varying periodic potential – a so-called optical lattice – generated from an optical standing-wave. Bes......The work reported in this thesis primarily focuses on studies of the dynamics of a single laser-cooled ion, simultaneously confined in the harmonic potential of a linear Paul trap and a rapidly varying periodic potential – a so-called optical lattice – generated from an optical standing...... calibration and analysis of the detection system, several theoretical simulations of the expected dynamics and associated optical response of the ion were undertaken. Finally, a new laser source based on second harmonic generation was developed in order to perform laser-cooling of Ca+ ions, and to serve...

  1. Ion implantation induced blistering of rutile single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Bing-Xi [School of Physics, Shandong University, Jinan, Shandong 250100 (China); Jiao, Yang [College of Physics and Electronics, Shandong Normal University, Jinan, Shandong 250100 (China); Guan, Jing [School of Physics, Shandong University, Jinan, Shandong 250100 (China); Wang, Lei [School of Physics, Shandong University, Jinan, Shandong 250100 (China); Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (China)

    2015-07-01

    The rutile single crystals were implanted by 200 keV He{sup +} ions with a series fluence and annealed at different temperatures to investigate the blistering behavior. The Rutherford backscattering spectrometry, optical microscope and X-ray diffraction were employed to characterize the implantation induced lattice damage and blistering. It was found that the blistering on rutile surface region can be realized by He{sup +} ion implantation with appropriate fluence and the following thermal annealing.

  2. Single Ion Trapping for the Enriched Xenon Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Waldman, Samuel J.; /Stanford U., Phys. Dept. /SLAC

    2006-03-28

    In the last decade, a variety of neutrino oscillation experiments have established that there is a mass difference between neutrino flavors, without determining the absolute neutrino mass scale. The Enriched Xenon Observatory for neutrinoless double beta decay (EXO) will search for the rare decays of xenon to determine the absolute value of the neutrino mass. The experiment uses a novel technique to minimize backgrounds, identifying the decay daughter product in real time using single ion spectroscopy. Here, we describe single ion trapping and spectroscopy compatible with the EXO detector. We extend the technique of single ion trapping in ultrahigh vacuum to trapping in xenon gas. With this technique, EXO will achieve a neutrino mass sensitivity of {approx_equal} .010 eV.

  3. Polarization-correlated photon pairs from a single ion

    CERN Document Server

    Rohde, F; Piro, N; Almendros, M; Schuck, C; Dubin, F; Eschner, J

    2009-01-01

    In the fluorescence light of a single atom, the probability for emission of a photon with certain polarization depends on the polarization of the photon emitted immediately before it. Here correlations of such kind are investigated with a single trapped calcium ion by means of second order correlation functions. A theoretical model is developed and fitted to the experimental data, which show 91% probability for the emission of polarization-correlated photon pairs within 24 ns.

  4. Precision Spectroscopy on Single Cold Trapped Molecular Nitrogen Ions

    Science.gov (United States)

    Hegi, Gregor; Najafian, Kaveh; Germann, Matthias; Sergachev, Ilia; Willitsch, Stefan

    2016-06-01

    The ability to precisely control and manipulate single cold trapped particles has enabled spectroscopic studies on narrow transitions of ions at unprecedented levels of precision. This has opened up a wide range of applications, from tests of fundamental physical concepts, e.g., possible time-variations of fundamental constants, to new and improved frequency standards. So far most of these experiments have concentrated on atomic ions. Recently, however, attention has also been focused on molecular species, and molecular nitrogen ions have been identified as promising candidates for testing a possible time-variation of the proton/electron mass ratio. Here, we report progress towards precision-spectroscopic studies on dipole-forbidden vibrational transitions in single trapped N2+ ions. Our approach relies on the state-selective generation of single N2+ ions, subsequent infrared excitation using high intensity, narrow-band quantum-cascade lasers and a quantum-logic scheme for non-destructive state readout. We also characterize processes limiting the state lifetimes in our experiment, which impair the measurement fidelity. P. O. Schmidt et. al., Science 309 (2005), 749. M. Kajita et. al., Phys. Rev. A 89 (2014), 032509 M. Germann , X. Tong, S. Willitsch, Nature Physics 10 (2014), 820. X. Tong, A. Winney, S. Willitsch, Phys. Rev. Lett. 105 (2010), 143001

  5. Probing surface electric field noise with a single ion

    CERN Document Server

    Daniilidis, N; Bolloten, G; Ramm, M; Ransford, A; Ulin-Avila, E; Talukdar, I; Häffner, H

    2013-01-01

    We report room-temperature electric field noise measurements combined with in-situ surface characterization and cleaning of a microfabricated ion trap. We used a single-ion electric field noise sensor in combination with surface cleaning and analysis tools, to investigate the relationship between electric field noise from metal surfaces in vacuum and the composition of the surface. These experiments were performed in a novel setup that integrates ion trapping capabilities with surface analysis tools. We find that surface cleaning of an aluminum-copper surface significantly reduces the level of electric field noise, but the surface does not need to be atomically clean to show noise levels comparable to those of the best cryogenic traps. The post-cleaning noise levels are low enough to allow fault-tolerant trapped-ion quantum information processing on a microfabricated surface trap.

  6. 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...

  7. Salt rejection in nanofiltration for single and binary salt mixtures in view of sulphate removal

    NARCIS (Netherlands)

    Krieg, H.M.; Modise, S.J.; Keizer, Klaas; Neomagus, H.W.J.P.

    2004-01-01

    Three commercial membranes (NF70, NF90 and TFC-SR) were firstly characterized in terms of pure water flux and the rejection of uncharged (alcohols and sugars) compounds. Subsequently, the rejection of monovalent (sodium and chloride) and divalent (calcium and sulphate) ions in single (NaCl, CaCl, an

  8. Salt: rejection in nanofiltration for single and binary salt mixtures in view of sulphate removal

    NARCIS (Netherlands)

    Krieg, H.M.; Modise, S.J.; Keizer, K.; Neomagus, H.W.J.P.

    2005-01-01

    Three commercial membranes (NF70, NF90 and TFC-SR) were firstly characterized in terms of pure water flux and the rejection of uncharged (alcohols and sugars) compounds. Subsequently, the rejection of monovalent (sodium and chloride) and divalent (calcium and sulphate) ions in single (NaCl, CaCl, an

  9. Salt rejection in nanofiltration for single and binary salt mixtures in view of sulphate removal

    NARCIS (Netherlands)

    Krieg, H.M.; Modise, S.J.; Keizer, Klaas; Neomagus, H.W.J.P.

    2004-01-01

    Three commercial membranes (NF70, NF90 and TFC-SR) were firstly characterized in terms of pure water flux and the rejection of uncharged (alcohols and sugars) compounds. Subsequently, the rejection of monovalent (sodium and chloride) and divalent (calcium and sulphate) ions in single (NaCl, CaCl,

  10. A compact source for bunches of singly charged atomic ions.

    Science.gov (United States)

    Murböck, T; Schmidt, S; Andelkovic, Z; Birkl, G; Nörtershäuser, W; Vogel, M

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 10(6) Mg(+) ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg(+) ions for sympathetic cooling of highly charged ions by laser-cooled (24)Mg(+).

  11. Cavity sideband cooling of a single trapped ion.

    Science.gov (United States)

    Leibrandt, David R; Labaziewicz, Jaroslaw; Vuletić, Vladan; Chuang, Isaac L

    2009-09-04

    We report a demonstration and quantitative characterization of one-dimensional cavity cooling of a single trapped (88)Sr(+) ion in the resolved-sideband regime. We measure the spectrum of cavity transitions, the rates of cavity heating and cooling, and the steady-state cooling limit. The cavity cooling dynamics and cooling limit of 22.5(3) motional quanta, limited by the moderate coupling between the ion and the cavity, are consistent with a simple model [Phys. Rev. A 64, 033405 (2001)] without any free parameters, validating the rate equation model for cavity cooling.

  12. Poisson-Fermi Model of Single Ion Activities

    CERN Document Server

    Liu, Jinn-Liang

    2015-01-01

    A Poisson-Fermi model is proposed for calculating activity coefficients of single ions in strong electrolyte solutions based on the experimental Born radii and hydration shells of ions in aqueous solutions. The steric effect of water molecules and interstitial voids in the first and second hydration shells play an important role in our model. The screening and polarization effects of water are also included in the model that can thus describe spatial variations of dielectric permittivity, water density, void volume, and ionic concentration. The activity coefficients obtained by the Poisson-Fermi model with only one adjustable parameter are shown to agree with experimental data, which vary nonmonotonically with salt concentrations.

  13. Ion beam nanopatterning in graphite: characterization of single extended defects

    Energy Technology Data Exchange (ETDEWEB)

    Melinon, P; Hannour, A; Bardotti, L; Prevel, B [Laboratoire de la Matiere Condensee et Nanostructures UMR 5586, Universite de Lyon, Universite Lyon I et CNRS, Batiment Lon Brillouin, 6 rue Ampere, Domaine de la Doua, F-69622 Villeurbanne (France); Gierak, J; Bourhis, E; Faini, G [Laboratoire de Photonique et de Nanostructures (LPN/CNRS), Route de Nozay, F-91560 Marcoussis (France); Canut, B [Institut des Nanotechnologies de Lyon UMR 5270, Universite de Lyon, Universite Lyon I et CNRS, Batiment Blaise Pascal, 7 avenue Jean Capelle, Domaine de la Doua, F-69622 Villeurbanne (France)], E-mail: pmelinon@lpmcn.univ-lyon1.fr

    2008-06-11

    The morphology and the electronic structure of a single focused ion-beam-induced artificial extended defect is probed by several methods including micro-Raman spectroscopy, atomic force and scanning tunneling microscopies and Monte Carlo and/or semi-analytical simulation within standard codes. The efficiency of the artificial defect for deposited metallic cluster pinning is also investigated. We show a correlation between the ion dose, morphology, electronic structure and cluster trapping efficiency. At room temperature, cluster pinning is efficient when the displacement per atom is one or more. Well-ordered patterned cluster networks are considered for potential applications.

  14. Ion beam nanopatterning in graphite: characterization of single extended defects.

    Science.gov (United States)

    Mélinon, P; Hannour, A; Bardotti, L; Prével, B; Gierak, J; Bourhis, E; Faini, G; Canut, B

    2008-06-11

    The morphology and the electronic structure of a single focused ion-beam-induced artificial extended defect is probed by several methods including micro-Raman spectroscopy, atomic force and scanning tunneling microscopies and Monte Carlo and/or semi-analytical simulation within standard codes. The efficiency of the artificial defect for deposited metallic cluster pinning is also investigated. We show a correlation between the ion dose, morphology, electronic structure and cluster trapping efficiency. At room temperature, cluster pinning is efficient when the displacement per atom is one or more. Well-ordered patterned cluster networks are considered for potential applications.

  15. Franck-Condon Physics in a Single Trapped Ion

    CERN Document Server

    Hu, Y M; Xu, Y Y; Zhou, F; Chen, L; Gao, Kelin; Feng, Mang; Lee, Chaohong

    2010-01-01

    We explore the Franck-Condon physics in a single ion confined in a spin-dependent potential, formed by the combination of a Paul trap and a gradient magnetic field. The correlation between electronic and vibrational degrees of freedom called as electron-vibron coupling is induced by a nonzero gradient. The strong electron-vibron coupling could be employed to suppress or even block some quantum vibrational transitions of the trapped ion. This collective phenomenon is known as the Franck-Condon blockade. Furthermore, we propose how to apply the ionic Franck-Condon physics for quantum logic operation, preparation of motional Fock state and sideband cooling.

  16. Single ion impact detection and scanning probe aligned ion implantation for quantum bit formation

    Energy Technology Data Exchange (ETDEWEB)

    Weis, Christoph D.

    2011-10-04

    Quantum computing and quantum information processing is a promising path to replace classical information processing via conventional computers which are approaching fundamental physical limits. Instead of classical bits, quantum bits (qubits) are utilized for computing operations. Due to quantum mechanical phenomena such as superposition and entanglement, a completely different way of information processing is achieved, enabling enhanced performance for certain problem sets. Various proposals exist on how to realize a quantum bit. Among them are electron or nuclear spins of defect centers in solid state systems. Two such candidates with spin degree of freedom are single donor atoms in silicon and nitrogen vacancy (NV) defect centers in diamond. Both qubit candidates possess extraordinary qualities which makes them promising building blocks. Besides certain advantages, the qubits share the necessity to be placed precisely in their host materials and device structures. A commonly used method is to introduce the donor atoms into the substrate materials via ion implantation. For this, focused ion beam systems can be used, or collimation techniques as in this work. A broad ion beam hits the back of a scanning probe microscope (SPM) cantilever with incorporated apertures. The high resolution imaging capabilities of the SPM allows the non destructive location of device areas and the alignment of the cantilever and thus collimated ion beam spot to the desired implant locations. In this work, this technique is explored, applied and pushed forward to meet necessary precision requirements. The alignment of the ion beam to surface features, which are sensitive to ion impacts and thus act as detectors, is demonstrated. The technique is also used to create NV center arrays in diamond substrates. Further, single ion impacts into silicon device structures are detected which enables deliberate single ion doping.

  17. Mg-ion indiffusion of lithium niobate single crystal fiber

    Institute of Scientific and Technical Information of China (English)

    阙文修; 姚熹; 霍玉晶

    1995-01-01

    A core-cladding waveguide structure of lithium niobate single crystal fiber with different refractive index profiles has been obtained by using an Mg-ion indiffusion process. The propagation loss of the dadded crystal fiber is measured to be 14 times as low as that of the undadded crystal fibers. Mechanisms of Mg-ion indiffusion and reasons of lattice distortion are analyzed and discussed. It is found by X-ray diffraction analysis as well as scanning electron microscopy that MgO-rich layer in the magnesium diffused surface exhibits the crystal structure of a new compound from the Li-Mg-Nb-O ternary system. It is proposed, for the first time, that this new compound in MgO-rich layer is the real source of Mg-ion indiffusion lithium niobate.

  18. Fragmentation dynamics of ammonia cluster ions after single photon ionisation

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, E.; Vries, J. de; Steger, H.; Menzel, C.; Kamke, W.; Hertel, I.V. (Freiburg Univ. (Germany, F.R.). Fakultaet fuer Physik Freiburg Univ. (Germany, F.R.). Freiburger Materialforschungszentrum)

    1991-01-01

    A reflecting time of flight mass spectrometer (RETOF) is used to study unimolecular and collision induced fragmentation of ammonia cluster ions. Synchrotron radiation from the BESSY electron storage ring is used in a range of photon energies from 9.08 up to 17.7 eV for single photon ionisation of neutral clusters in a supersonic beam. The threshold photoelectron photoion coincidence technique (TPEPICO) is used to define the energy initially deposited into the cluster ions. Metastable unimolecular decay ({mu}s range) is studied using the RETOF's capacity for energy analysis. Under collision free conditions the by far most prominent metastable process is the evaporation of one neutral NH{sub 3} monomer from protonated clusters (NH{sub 3}){sub x}NH{sub 4}{sup +}. Abundance of homogeneous vs. protonated cluster ions and of metastable fragments are reported as a function of photon energy and cluster size up to n=10. (orig.).

  19. Atomic parity violation in a single Ra ion

    Energy Technology Data Exchange (ETDEWEB)

    Nunes Portela, M.; Beker, H.; Giri, G.; Jungmann, K.; Onderwater, C.J.G.; Schlesser, S.; Timmermans, R.G.E.; Versolato, O.O.; Willmann, L.; Wilschut, H.W. [KVI, University of Groningen, NL (Germany)

    2012-07-01

    Precision measurements of atomic parity violation is the only path to determine the electroweak mixing angle in the Standard Model of particle physics at low energy scale. A single trapped Ra{sup +} ion is the most promising candidate for such an experiment. The system combines the advantages of large parity violation amplitudes due to the faster than Z{sup 3} scaling, the possibility to perform accurate atomic structure calculation on this one valence electron system and the ability to precision frequency measurements on trapped ion. Our first laser spectroscopy on an ensemble of trapped short-lived {sup 209-214}Ra{sup +} isotopes in a linear Paul trap provided hyperfine structure of the 6d {sup 2}D{sub 3/2} states and isotope shift of the 6d {sup 2}D{sub 3/2} - 7p {sup 2}P{sub 1/2} transition. These results provide input for the ongoing precision atomic structure calculations. The next step of the experiments towards laser cooling of a single trapped radium ion. The experimental setup is being commissioned with Ba ions.

  20. Atomic parity violation in a single trapped radium ion

    Energy Technology Data Exchange (ETDEWEB)

    Versolato, O. O., E-mail: versolato@kvi.nl; Wansbeek, L. W.; Giri, G. S.; Berg, J. E. van den; Hoek, D. J. van der; Jungmann, K.; Kruithof, W. L.; Onderwater, C. J. G.; Sahoo, B. K.; Santra, B.; Shidling, P. D.; Timmermans, R. G. E.; Willmann, L.; Wilschut, H. W. [University of Groningen, Kernfysisch Versneller Instituut (Netherlands)

    2011-07-15

    Atomic parity violation (APV) experiments are sensitive probes of the electroweak interaction at low energy. These experiments are competitive with and complementary to high-energy collider experiments. The APV signal is strongly enhanced in heavy atoms and it is measurable by exciting suppressed (M1, E2) transitions. The status of APV experiments and theory are reviewed as well as the prospects of an APV experiment using one single trapped Ra{sup + } ion. The predicted enhancement factor of the APV effect in Ra{sup + } is about 50 times larger than in Cs atoms. However, certain spectroscopic information on Ra{sup + } needed to constrain the required atomic many-body theory, was lacking. Using the AGOR cyclotron and the TRI{mu}P facility at KVI in Groningen, short-lived {sup 212 - 214}Ra{sup + } ions were produced and trapped. First ever excited-state laser spectroscopy was performed on the trapped ions. These measurements provide a benchmark for the atomic theory required to extract the electroweak mixing angle to sub-1% accuracy and are an important step towards an APV experiment in a single trapped Ra{sup + } ion.

  1. Probing isotope effects in chemical reactions using single ions

    CERN Document Server

    Staanum, Peter F; Wester, Roland; Drewsen, Michael

    2008-01-01

    Isotope effects in reactions between Mg+ in the 3p 2P3/2 excited state and molecular hydrogen at thermal energies are studied through single reaction events. From only ~250 reactions with HD, the branching ratio between formation of MgD+ and MgH+ is found to be larger than 5. From additional 65 reactions with H2 and D2 we find that the overall decay probability of the intermediate MgH2+, MgHD+ or MgD2+ complexes is the same. Our study shows that few single ion reactions can provide quantitative information on ion-neutral reactions. Hence, the method is well-suited for reaction studies involving rare species, e.g., rare isotopes or short-lived unstable elements.

  2. Freestanding single-crystalline magnetic structures fabricated by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Schoenherr, P.; Bischof, A.; Boehm, B.; Eib, P.; Grimm, S.; Gross, L.; Allenspach, R., E-mail: ral@zurich.ibm.com [IBM Research – Zurich, 8803 Rüschlikon (Switzerland); Alvarado, S. F. [Department of Materials, ETH Zürich, 8093 Zürich (Switzerland)

    2015-01-19

    Starting from an ultrathin Fe film grown epitaxially on top of a GaAs(001) substrate, we show that freestanding structures can be created by ion-beam treatment. These structures are single-crystalline blisters and only a few nanometers thick. Anisotropic stress in the rim of a blister induces magnetic domain states magnetized in the direction normal to the blister edge. Experimental evidence is provided that the lateral size can be confined by starting from a nanostructured template.

  3. Spatially frustrated S = 1 Heisenberg antiferromagnet with single ion anisotropy

    Science.gov (United States)

    Pires, A. S. T.

    2016-10-01

    Using the SU(3) Schwinger boson formalism, I study the S = 1 square lattice Heisenberg antiferromagnet, at zero temperature, with spatially anisotropic nearest-neighbor couplings frustrated by a next-nearest neighbor interaction and single ion anisotropy. The phase diagram at zero temperature is presented. My calculations show two magnetically ordered phases separated by a quantum-disordered region for all values of the anisotropy.

  4. Applications of heavy ion microprobe for single event effects analysis

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Robert A. [Electrical Engineering and Computer Science, Vanderbilt University, 5635 Stevenson Center, Nashville, TN 37235 (United States)]. E-mail: robert.reed@vanderbilt.edu; Vizkelethy, Gyorgy [Sandia National Laboratory, Albuquerque, NM 87185 (United States); Pellish, Jonathan A. [Electrical Engineering and Computer Science, Vanderbilt University, 5635 Stevenson Center, Nashville, TN 37235 (United States); Sierawski, Brian [Institute for Space and Defense Electronics, Vanderbilt University, Box 351821 Station B, Nashville, TN 37235 (United States); Warren, Kevin M. [Institute for Space and Defense Electronics, Vanderbilt University, Box 351821 Station B, Nashville, TN 37235 (United States); Porter, Mark [Medtronic Microelectronics Center, 2343 W. Medtronic Way, Tempe, AZ 85281 (United States); Wilkinson, Jeff [Medtronic, CRDM Device Technology, 7000 Central Avenue NE, Minneapolis, MN 55432 (United States); Marshall, Paul W. [NASA consultant, Brookneal, VA 24528 (United States); Niu, Guofu [Auburn University, Auburn, AL 36894 (United States); Cressler, John D. [Georgia Institute of Technology, Atlanta, GA 30332 (United States); Schrimpf, Ronald D. [Electrical Engineering and Computer Science, Vanderbilt University, 5635 Stevenson Center, Nashville, TN 37235 (United States); Tipton, Alan [Electrical Engineering and Computer Science, Vanderbilt University, 5635 Stevenson Center, Nashville, TN 37235 (United States); Weller, Robert A. [Electrical Engineering and Computer Science, Vanderbilt University, 5635 Stevenson Center, Nashville, TN 37235 (United States)

    2007-08-15

    The motion of ionizing-radiation-induced rogue charge carriers in a semiconductor can create unwanted voltage and current conditions within a microelectronic circuit. If sufficient unwanted charge or current occurs on a sensitive node, a variety of single event effects (SEEs) can occur with consequences ranging from trivial to catastrophic. This paper describes the application of heavy ion microprobes to assist with calibration and validation of SEE modeling approaches.

  5. Conduction Mechanisms and Structure of Ionomeric Single-Ion Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Colby, Ralph H. [Pennsylvania State Univ., University Park, PA (United States); Maranas, Janna K. [Pennsylvania State Univ., University Park, PA (United States); Mueller, Karl T. [Pennsylvania State Univ., University Park, PA (United States); Runt, James [Pennsylvania State Univ., University Park, PA (United States); Winey, Karen I. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2015-03-01

    Our team has designed using DFT (Gaussian) and synthesized low glass transition temperature single-ion conductors that are either polyanions that conduct small cations Li+, Na+, Cs+ or polycations that conduct small anions F-, OH-, Br-. We utilize a wide range of complimentary experimental materials characterization tools to understand ion transport; differential scanning calorimetry, dielectric relaxation spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, linear viscoelasticity, X-ray scattering and molecular dynamics simulations. The glass transition temperature Tg needs to be as low as possible to facilitate ion transport, so the nonionic parts of the polymer need to be polar, flexible and have strong solvation interactions with the ions. The lowest Tg we have managed for polyanions conducting Li+ is -60 °C. In contrast, polysiloxanes with PEO side chains and tetrabutylphosphonium cationic side groups have Tg ≈ -75 °C that barely increases with ion content, as anticipated by DFT. A survey of all polyanions in the literature suggests that Tg < -80 °C is needed to achieve the 10-4 S/cm conductivity needed for battery separators.

  6. Conduction Mechanisms and Structure of Ionomeric Single-Ion Conductors

    Energy Technology Data Exchange (ETDEWEB)

    Colby, Ralph H.; Maranas, Janna K; Mueller, Karl T; Runt, James; Winey, Karen I

    2015-03-05

    Our team has designed using DFT (Gaussian) and synthesized low glass transition temperature single-ion conductors that are either polyanions that conduct small cations Li, Na, Cs or polycations that conduct small anions F, OH, Br. We utilize a wide range of complimentary experimental materials charactization tools to understand ion transport; differential scanning calorimetry, dielectric relaxation spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, linear viscoelasticity, X-ray scattering and molecular dynamics simulations. The glass transition temperature Tg needs to be as low as possible to facilitate ion transport, so the nonionic parts of the polymer need to be polar, flexible and have strong solvation interactions with the ions. The lowest Tg we have managed for polyanions conducting Li is -60 C. In contrast, polysiloxanes with PEO side chains and tetrabutylphosphonium cationic side groups have Tg ~ -75C that barely increases with ion content, as anticipated by DFT. A survey of all polyanions in the literature suggests that Tg < -80C is needed to achieve the 10-4 S/cm conductivity needed for battery separators.

  7. Experimental Improvement of Signal of a Single Laser-Cooled Trapped 40Ca+ Ion

    Institute of Scientific and Technical Information of China (English)

    SHU Hua-Lin; QUO Bin; GUAN Hua; LIU Qu; HUANG Xue-Ren; GAO Ke-Lin

    2007-01-01

    A single 40Ca+ ion is loaded in a miniature Paul trap and the probability of directly loading a single ion is above 50%. The signal-to-noise ratio and the storage time for a single ion have been improved by minimizing the ion micromotion and locking a 397 nm cooling laser to a Fabry-Perot interferometer and optogalvanic signal. From the fluorescence spectrum, the ion temperature is estimated to be about 5mK.

  8. Design of a single ion facility and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Cholewa, M.; Saint, A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The use of micro-irradiation techniques in radiobiology is not new; however, the current techniques take advantage of recent developments in particle delivery, focussing detection, image processing, cell recognition and computer control. These developments have generally come from other fields, for example microbeam elemental analysis techniques and single-event upset testing of semiconductor devices. Also in radiation biology there have been important advances in developments of individual cell assays, which allow a wide range of endpoints to be studied with good accuracy at low doses. Many of the studies that are planned involve following the responses of individual cells after a programmed exposure to charged-particle traversals. To probe the radiation sensitivity of a single cell and/or its constituents with a submicron resolution several developments are needed. The essential parameters of the proposed system can be summarised as follows: a focussed beam of ions of 300nm or less at the cell; a reliable (close to 100%) single ion detection; a fast beam switch to prevent second hits; a target holder adapted for the irradiation of wet cells and a fully automated system for cell recognition and single hits. 1 fig.

  9. Connecting single-ion magnets through ligand dimerisation.

    Science.gov (United States)

    Lin, Po-Heng; Korobkov, Ilia; Burchell, Tara J; Murugesu, Muralee

    2012-11-28

    A mononuclear as well as dinuclear Dy(III) complexes of general formula [Dy(hmb)(NO(3))(2)(DMF)(2)] (1) and [Dy(2)(hmt)(NO(3))(4)(DMF)(4)]·DMF (2), where Hhmb: (N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide and H(2)hmt: (N(1),N(4))-N'(1),N'(4)-bis(2-hydroxy-3-methoxybenzylidene)terephthalohydrazide were obtained using a synthetic strategy involving a polytopic Schiff base ligand. Single-crystal X-ray analysis reveals the Dy(III) ion is in a distorted pentagonal interpenetrating tetrahedral arrangement. The two symmetrical Dy(III) ions in complex 2 exhibit the same geometry and are well-isolated in the molecule by an hmt(2-) ligand. The direct current (dc) and alternating current (ac) magnetic measurements of the compounds were investigated. Complex 1 did not exhibit any ac signal whereas a frequency dependant signal was observed for 2 under zero dc field. When an optimum dc field was applied, clear frequency dependant signals were obtained for both complexes indicative of Single-Ion Magnet behaviour with relaxation barriers of U(eff) = 34 and 42 K for 1 and 2, respectively.

  10. High-precision experiments on a single trapped radium ion

    Energy Technology Data Exchange (ETDEWEB)

    Boell, O.; Giri, G.S.; Jungmann, K.; Sahoo, B.K.; Timmermans, R.G.E.; Versolato, O.O.; Wansbeek, L.W.; Willmann, L. [KVI, University of Groningen (Netherlands)

    2009-07-01

    A single, trapped radium ion is an ideal candidate for high precision experiments. Two Ra{sup +} experiments are under construction at KVI. Ultra-narrow transitions in radium ions provide an excellent basis for an all-optical, high-stability frequency standard, i.e. a clock. The off-the-shelf availability of semiconductor lasers for all necessary transitions is highly advantageous. In certain odd isotopes of radium, the nuclear electric quadrupole shift is absent. The same system and experimental hardware will be used to search for physics beyond the Standard Model of particle physics by measuring Atomic Parity Violation. This will serve as a low-energy test of the running of the electroweak mixing angle. Recent calculations have shown Ra{sup +} to be the superior candidate. Recently we have succeeded in the production and efficient slowing down of isotopes around {sup 213}Ra at the AGOR cyclotron and the TRI{mu}P facility of KVI. Progress has been made in the development of ion traps and in the laser set-up in a dedicated laser laboratory. Laser spectroscopy of the radium ion and the first ever trapping of this particle are planned in the near future.

  11. Ion implantation of CdTe single crystals

    Directory of Open Access Journals (Sweden)

    Wiecek Tomasz

    2017-01-01

    Full Text Available Ion implantation is a technique which is widely used in industry for unique modification of metal surface for medical applications. In semiconductor silicon technology ion implantation is also widely used for thin layer electronic or optoelectronic devices production. For other semiconductor materials this technique is still at an early stage. In this paper based on literature data we present the main features of the implantation of CdTe single crystals as well as some of the major problems which are likely to occur when dealing with them. The most unexpected feature is the high resistance of these crystals against the amorphization caused by ion implantation even at high doses (1017 1/cm2. The second property is the disposal of defects much deeper in the sample then it follows from the modeling calculations. The outline of principles of the ion implantation is included in the paper. The data based on RBS measurements and modeling results obtained by using SRIM software were taken into account.

  12. Ion implantation of CdTe single crystals

    Science.gov (United States)

    Wiecek, Tomasz; Popovich, Volodymir; Bester, Mariusz; Kuzma, Marian

    2016-12-01

    Ion implantation is a technique which is widely used in industry for unique modification of metal surface for medical applications. In semiconductor silicon technology ion implantation is also widely used for thin layer electronic or optoelectronic devices production. For other semiconductor materials this technique is still at an early stage. In this paper based on literature data we present the main features of the implantation of CdTe single crystals as well as some of the major problems which are likely to occur when dealing with them. The most unexpected feature is the high resistance of these crystals against the amorphization caused by ion implantation even at high doses (1017 1/cm2). The second property is the disposal of defects much deeper in the sample then it follows from the modeling calculations. The outline of principles of the ion implantation is included in the paper. The data based on RBS measurements and modeling results obtained by using SRIM software were taken into account.

  13. A simple radionuclide-driven single-ion source

    CERN Document Server

    Díez, M Montero; Fairbank, W; Gratta, G; Barbeau, P S; Barry, K; DeVoe, R; Dolinski, M J; Green, M; LePort, F; Müller, A R; Neilson, R; O'Sullivan, K; Ackerman, N; Aharmin, B; Auger, M; Benitez-Medina, C; Breidenbach, M; Burenkov, A; Cook, S; Daniels, T; Donato, K; Farine, J; Giroux, G; Gornea, R; Graham, K; Hagemann, C; Hall, C; Hall, K; Hallman, D; Hargrove, C; Herrin, S; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K; Lacey, J; Leonard, D S; Mackay, D; MacLellan, R; Mong, B; Niner, E; Odian, A; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rollin, E; Rowson, P C; Sinclair, D; Slutsky, S; Stekhanov, V; Vuilleumier, J -L; Wichoski, U; Wodin, J; Yang, L; Yen, Y -R

    2010-01-01

    We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating 148Gd onto a silicon {\\alpha}-particle detector and vapor depositing a layer of BaF2 over it. 144Sm recoils from the alpha decay of 148Gd are used to dislodge Ba+ ions from the BaF2 layer and emit them in the surrounding environment. The simultaneous detection of an {\\alpha} particle in the substrate detector allows for tagging of the nuclear decay and of the Ba+ emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

  14. A simple radionuclide-driven single-ion source

    Energy Technology Data Exchange (ETDEWEB)

    Montero Diez, M.; Twelker, K.; Gratta, G.; Barbeau, P. S.; Barry, K.; DeVoe, R.; Dolinski, M. J.; Green, M.; LePort, F.; Mueller, A. R.; Neilson, R.; O' Sullivan, K. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Fairbank, W. Jr.; Benitez-Medina, C.; Cook, S.; Hall, K.; Mong, B. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Ackerman, N.; Breidenbach, M.; Herrin, S. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); and others

    2010-11-15

    We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating {sup 148}Gd onto a silicon {alpha}-particle detector and vapor depositing a layer of BaF{sub 2} over it. {sup 144}Sm recoils from the alpha decay of {sup 148}Gd are used to dislodge Ba{sup +} ions from the BaF{sub 2} layer and emit them in the surrounding environment. The simultaneous detection of an {alpha} particle in the substrate detector allows for tagging of the nuclear decay and of the Ba{sup +} emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

  15. Three dimensional reconstruction of therapeutic carbon ion beams in phantoms using single secondary ion tracks

    CERN Document Server

    Reinhart, Anna Merle; Jakubek, Jan; Martisikova, Maria

    2016-01-01

    Carbon ion beam radiotherapy enables a very localised dose deposition. However, already small changes in the patient geometry or positioning errors can significantly distort the dose distribution. A live monitoring system of the beam delivery within the patient is therefore highly desirable and could improve patient treatment. We present a novel three-dimensional imaging method of the beam in the irradiated object, exploiting the measured tracks of single secondary ions emerging under irradiation. The secondary particle tracks are detected with a TimePix stack, a set of parallel pixelated semiconductor detectors. We developed a three-dimensional reconstruction algorithm based on maximum likelihood expectation maximisation. We demonstrate the applicability of the new method in an irradiation of a cylindrical PMMA phantom of human head size with a carbon ion pencil beam of 226MeV/u. The beam image in the phantom is reconstructed from a set of 9 discrete detector positions between -80 and 50 degrees from the bea...

  16. Laserspray ionization on a commercial atmospheric pressure-MALDI mass spectrometer ion source: selecting singly or multiply charged ions.

    Science.gov (United States)

    McEwen, Charles N; Larsen, Barbara S; Trimpin, Sarah

    2010-06-15

    Multiply charged ions, similar to those obtained with electrospray ionization, are produced at atmospheric pressure (AP) using standard MALDI conditions of laser fluence and reflective geometry. Further, the charge state can be switched to singly charged ions nearly instantaneously by changing the voltage applied to the MALDI target plate. Under normal AP-MALDI operating conditions in which a voltage is applied to the target plate, primarily singly charged ions are observed, but at or near zero volts, highly charged ions are observed for peptides and proteins. Thus, switching between singly and multiply charged ions requires only manipulation of a single voltage. As in ESI, multiple charging, produced using the AP-MALDI source, allows compounds with molecular weights beyond the mass-to-charge limit of the mass spectrometer to be observed and improves the fragmentation relative to singly charged ions.

  17. Ion-track based single-channel templates for single-nanowire contacting

    Science.gov (United States)

    Chtanko, N.; Toimil-Molares, M. E.; Cornelius, T. W.; Dobrev, D.; Neumann, R.

    2005-07-01

    This work reports a procedure for the fabrication of membranes containing only one single channel with diameter down to 20 nm and with well-defined geometry. Foils of different types of polymer (polyethylene terephthalate (PET) and polycarbonate (PC)) were tested with respect to their suitability as ion-track template for single-nanowire growth. Membranes with one pore were created by the track-etching technique. The pore size was characterized by electrical conductivity measurements in 1 M KCl. Furthermore, we developed also a method for the preparation and electrical contacting of single metallic nanowires. Cylindrical single pores were filled with Bi by electrochemical deposition. The resulting wires, remaining embedded in the polymer foil, are very suitable for measurements of electrical resistance as a function of parameters such as wire diameter and temperature.

  18. Dynamics of ions in a water drop using the AMOEBA polarizable force field

    Science.gov (United States)

    Thaunay, Florian; Ohanessian, Gilles; Clavaguéra, Carine

    2017-03-01

    Various ions carrying a charge from -2 to +3 were confined in a drop of 100 water molecules as a way to model coordination properties inside the cluster and at the interface. The behavior of the ions has been followed by molecular dynamics with the AMOEBA polarizable force field. Multiply charged ions and small singly charged ions are found to lie inside the droplet, while bigger monovalent ions sit near the surface. The results provide a coherent picture of average structural properties as well as residence times for which a general trend is proposed, especially for the anions.

  19. A Single Laser Cooled Trapped 40Ca+ Ion in a Miniature Paul Trap

    Institute of Scientific and Technical Information of China (English)

    SHU Hua-Lin; GUAN Hua; HUANG Xue-Ren; LI Jiao-Mei; GAO Ke-Lin

    2005-01-01

    @@ We have observed the phenomenon of phase transition of a few trapped ions in a miniature Paul trap. Judging from the quantum jump signals, a single laser-cooled trapped Ca+ ion has been realized. The ion temperature is estimated to be 22mK. The result shows that the amplitude of ion micromotion is strongly dependent on the rf voltage.

  20. Modifications of gallium phosphide single crystals using slow highly charged ions and swift heavy ions

    Science.gov (United States)

    El-Said, A. S.; Wilhelm, R. A.; Heller, R.; Akhmadaliev, Sh.; Schumann, E.; Sorokin, M.; Facsko, S.; Trautmann, C.

    2016-09-01

    GaP single crystals were irradiated with slow highly charged ions (HCI) using 114 keV 129Xe(33-40)+ and with various swift heavy ions (SHI) of 30 MeV I9+ and 374 MeV-2.2 GeV 197Au25+. The irradiated surfaces were investigated by scanning force microscopy (SFM). The irradiations with SHI lead to nanohillocks protruding from the GaP surfaces, whereas no changes of the surface topography were observed after the irradiation with HCI. This result indicates that a potential energy above 38.5 keV is required for surface nanostructuring of GaP. In addition, strong coloration of the GaP crystals was observed after irradiation with SHI. The effect was stronger for higher energies. This was confirmed by measuring an increased extinction coefficient in the visible light region.

  1. Real single ion solvation free energies with quantum mechanical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, Timothy TS; Baer, Marcel D.; Schenter, Gregory K.; Mundy, Christopher J.

    2017-09-01

    Single ion solvation free energies are one of the most important properties of electrolyte solution and yet there is ongoing debate about what these values are. Experimental methods can only determine the values for neutral ion pairs. Here, we use DFT interaction potentials with molecular dynamics simulation (DFT-MD) combined with a modified version of the quasi chemical theory (QCT) to calculate these energies for the lithium and fluoride ions. A new method to rigorously correct for the error in the DFT functional is developed and very good agreement with the experimental value for the lithium fluoride pair is obtained. Moreover, this method partitions the energies into physically intuitive terms such as surface potential, cavity and charging energies which are amenable to descriptions with reduced models. Our research suggests that lithium’s solvation energy is dominated by the free energetics of a charged hard sphere, whereas fluoride exhibits significant quantum mechanical behavior that cannot be simply described with a reduced model. We would like to thank Thomas Beck, Shawn Kathmann and Sotiris Xantheas for helpful discussions. Computing resources were generously allocated by PNNLs Institutional Computing program. This research also used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. TTD, GKS and CJM were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. MDB was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative, a Laboratory Directed Research and Development Program at Pacific Northwest National Laboratory (PNNL). PNNL is a multi-program national laboratory operated by Battelle for the U.S. Department of Energy.

  2. Determination of transition frequencies in a single $^{138}$Ba$^{+}$ ion

    CERN Document Server

    Dijck, E A; Grier, A T; Jungmann, K; Mohanty, A; Valappol, N; Willmann, L

    2015-01-01

    Transition frequencies between low-lying energy levels in a single trapped $^{138}$Ba$^{+}$ ion have been measured with laser spectroscopy referenced to an optical frequency comb. By extracting the frequencies of one-photon and two-photon components of the line shape using an eight-level optical Bloch model, we achieved 0.1 MHz accuracy for the 5d $^{2}$D$_{3/2}$ - 6p $^{2}$P$_{1/2}$ and 6s $^{2}$S$_{1/2}$ - 5d $^{2}$D$_{3/2}$ transition frequencies, and 0.2 MHz for the 6s $^{2}$S$_{1/2}$ - 6p $^{2}$P$_{1/2}$ transition frequency.

  3. Single-ion microwave near-field quantum sensor

    Science.gov (United States)

    Wahnschaffe, M.; Hahn, H.; Zarantonello, G.; Dubielzig, T.; Grondkowski, S.; Bautista-Salvador, A.; Kohnen, M.; Ospelkaus, C.

    2017-01-01

    We develop an intuitive model of 2D microwave near-fields in the unusual regime of centimeter waves localized to tens of microns. Close to an intensity minimum, a simple effective description emerges with five parameters that characterize the strength and spatial orientation of the zero and first order terms of the near-field, as well as the field polarization. Such a field configuration is realized in a microfabricated planar structure with an integrated microwave conductor operating near 1 GHz. We use a single 9 Be+ ion as a high-resolution quantum sensor to measure the field distribution through energy shifts in its hyperfine structure. We find agreement with simulations at the sub-micron and few-degree level. Our findings give a clear and general picture of the basic properties of oscillatory 2D near-fields with applications in quantum information processing, neutral atom trapping and manipulation, chip-scale atomic clocks, and integrated microwave circuits.

  4. Single-photon single ionization of W$^{+}$ ions: experiment and theory

    CERN Document Server

    Müller, A; Hellhund, J; Holste, K; Kilcoyne, A L D; Phaneuf, R A; Ballance, C P; McLaughlin, B M

    2015-01-01

    Experimental and theoretical results are reported for photoionization of Ta-like (W$^{+}$) tungsten ions. Absolute cross sections were measured in the energy range 16 to 245 eV employing the photon-ion merged-beam setup at the Advanced Light Source in Berkeley. Detailed photon-energy scans at 100 meV bandwidth were performed in the 16 to 108 eV range. In addition, the cross section was scanned at 50 meV resolution in regions where fine resonance structures could be observed. Theoretical results were obtained from a Dirac-Coulomb R-matrix approach. Photoionization cross section calculations were performed for singly ionized atomic tungsten ions in their $5s^2 5p^6 5d^4({^5}D)6s \\; {^6}{\\rm D}_{J}$, $J$=1/2, ground level and the associated excited metastable levels with $J$=3/2, 5/2, 7/2 and 9/2. Since the ion beams used in the experiments must be expected to contain long-lived excited states also from excited configurations, additional cross-section calculations were performed for the second-lowest term, $5d^5...

  5. Single-Ion Implantation for the Development of Si-Based MOSFET Devices with Quantum Functionalities

    Directory of Open Access Journals (Sweden)

    Jeffrey C. McCallum

    2012-01-01

    Full Text Available Interest in single-ion implantation is driven in part by research into development of solid-state devices that exhibit quantum behaviour in their electronic or optical characteristics. Here, we provide an overview of international research work on single ion implantation and single ion detection for development of electronic devices for quantum computing. The scope of international research into single ion implantation is presented in the context of our own research in the Centre for Quantum Computation and Communication Technology in Australia. Various single ion detection schemes are presented, and limitations on dopant placement accuracy due to ion straggling are discussed together with pathways for scale-up to multiple quantum devices on the one chip. Possible future directions for ion implantation in quantum computing and communications are also discussed.

  6. Response of a DRAM to single-ion tracks of different heavy-ion species and stopping powers

    Science.gov (United States)

    Zoutendyk, J. A.; Smith, L. S.; Edmonds, L. D.

    1990-01-01

    Multiple-bit errors caused by single-ion tracks in a 256-kb DRAM fabricated by a bulk process were observed for different ion species and stopping power values. The results demonstrate the utility of this device for the evaluation of ion-beam uniformity and ion-beam-induced charge collection in IC devices. The data indicate that single-ion-induced charge transport results in multiple-bit error clusters due to lateral diffusion of excess minority carriers (electrons). Charge collection occurred from a depth of up to 35 microns from the surface of the device. An apparent charge loss was observed for very heavy ions with a high stopping power (Au at 350 MeV).

  7. A reliable method for the counting and control of single ions for single-dopant controlled devices.

    Science.gov (United States)

    Shinada, T; Kurosawa, T; Nakayama, H; Zhu, Y; Hori, M; Ohdomari, I

    2008-08-27

    By 2016, transistor device size will be just 10 nm. However, a transistor that is doped at a typical concentration of 10(18) atoms cm(-3) has only one dopant atom in the active channel region. Therefore, it can be predicted that conventional doping methods such as ion implantation and thermal diffusion will not be available ten years from now. We have been developing a single-ion implantation (SII) method that enables us to implant dopant ions one-by-one into semiconductors until the desired number is reached. Here we report a simple but reliable method to control the number of single-dopant atoms by detecting the change in drain current induced by single-ion implantation. The drain current decreases in a stepwise fashion as a result of the clusters of displaced Si atoms created by every single-ion incidence. This result indicates that the single-ion detection method we have developed is capable of detecting single-ion incidence with 100% efficiency. Our method potentially could pave the way to future single-atom devices, including a solid-state quantum computer.

  8. Activation and inhibition of histone deacetylase 8 by monovalent cations.

    Science.gov (United States)

    Gantt, Stephanie L; Joseph, Caleb G; Fierke, Carol A

    2010-02-26

    The metal-dependent histone deacetylases (HDACs) catalyze hydrolysis of acetyl groups from acetyllysine side chains and are targets of cancer therapeutics. Two bound monovalent cations (MVCs) of unknown function have been previously observed in crystal structures of HDAC8; site 1 is near the active site, whereas site 2 is located > 20 A from the catalytic metal ion. Here we demonstrate that one bound MVC activates catalytic activity (K(1/2) = 3.4 mM for K(+)), whereas the second, weaker-binding MVC (K(1/2) = 26 mM for K(+)) decreases catalytic activity by 11-fold. The weaker binding MVC also enhances the affinity of the HDAC inhibitor suberoylanilide hydroxamic acid by 5-fold. The site 1 MVC is coordinated by the side chain of Asp-176 that also forms a hydrogen bond with His-142, one of two histidines important for catalytic activity. The D176A and H142A mutants each increase the K(1/2) for potassium inhibition by > or = 40-fold, demonstrating that the inhibitory cation binds to site 1. Furthermore, the MVC inhibition is mediated by His-142, suggesting that this residue is protonated for maximal HDAC8 activity. Therefore, His-142 functions either as an electrostatic catalyst or a general acid. The activating MVC binds in the distal site and causes a time-dependent increase in activity, suggesting that the site 2 MVC stabilizes an active conformation of the enzyme. Sodium binds more weakly to both sites and activates HDAC8 to a lesser extent than potassium. Therefore, it is likely that potassium is the predominant MVC bound to HDAC8 in vivo.

  9. Ion-induced nucleation of dibutyl phthalate vapors on spherical and nonspherical singly and multiply charged polyethylene glycol ions.

    Science.gov (United States)

    Nasibulin, Albert G; de la Mora, Juan Fernandez; Kauppinen, Esko I

    2008-02-14

    Dibutyl phthalate vapor nucleation induced by positive polyethylene glycol (PEG) ions with controlled sizes and charges was experimentally studied. The ions were produced by electrospray ionization, classified in a high-resolution differential mobility analyzer, and studied in a nano condensation nucleus counter of the mixing type. Ionic radii of PEG varied from 0.52 to 1.56 nm, including from singly to quadruply charged ions. Some of these ions are fully stretched chains, other are spherical, and others have intermediate forms, all of them having been previously characterized by mobility and mass spectrometry studies. Activation of PEG1080(+2) requires a supersaturation almost as high as that required for small singly charged ions and higher than for PEG1080(+). This anomaly is explained by the Coulombic stretching of the ion into a long chain, where the two charged centers appear to be relatively decoupled from each other. The critical supersaturation for singly charged spherical ions falls below Thomson's (capillary) theory and even below the already low values seen previously for tetraheptyl ammonium bromide clusters. Spherical PEG4120(+2) falls close to the Thomson curve. The trends observed for slightly nonspherical PEG4120(+3) and highly nonspherical (but not quite linear) PEG4120(+4) are intermediate between those of multiply charged spheres and small singly charged ions.

  10. Single-ion and single-chain magnetism in triangular spin-chain oxides

    Science.gov (United States)

    Seikh, Md. Motin; Caignaert, Vincent; Perez, Olivier; Raveau, Bernard; Hardy, Vincent

    2017-05-01

    S r4 -xC axM n2Co O9 oxides (x =0 and x =2 ) are found to exhibit magnetic responses typical of single-chain magnets (SCMs) and single-ion magnets (SIMs), two features generally investigated in coordination polymers or complexes. The compound x =0 appears to be a genuine SCM, in that blocking effects associated with slow spin dynamics yield remanence and coercivity in the absence of long-range ordering (LRO). In addition, SIM signatures of nearly identical nature are detected in both compounds, coexisting with SCM in x =0 and with LRO in x =2 . It is also observed that a SCM response can be recovered in x =2 after application of magnetic field. These results suggest that purely inorganic systems could play a valuable role in the topical issue of the interplay among SIM, SCM, and LRO phenomena in low-dimensional magnetism.

  11. Quantum Otto engine using a single ion and a single thermal bath

    Science.gov (United States)

    Biswas, Asoka; Chand, Suman

    2016-05-01

    Quantum heat engines employ a quantum system as the working fluid, that gives rise to large work efficiency, beyond the limit for classical heat engines. Existing proposals for implementing quantum heat engines require that the system interacts with the hot bath and the cold bath (both modelled as a classical system) in an alternative fashion and therefore assumes ability to switch off the interaction with the bath during a certain stage of the heat-cycle. However, it is not possible to decouple a quantum system from its always-on interaction with the bath without use of complex pulse sequences. It is also hard to identify two different baths at two different temperatures in quantum domain, that sequentially interact with the system. Here, we show how to implement a quantum Otto engine without requiring to decouple the bath in a sequential manner. This is done by considering a single thermal bath, coupled to a single trapped ion. The electronic degree of freedom of the ion is chosen as a two-level working fluid while the vibrational degree of freedom plays the role of the cold bath. Measuring the electronic state mimics the release of heat into the cold bath. Thus, our model is fully quantum and exhibits very large work efficiency, asymptotically close to unity.

  12. Active experiments and single ion motion in the magnetotail

    Science.gov (United States)

    Rothwell, P. L.; Yates, G. K.

    1983-07-01

    Analytic solutions to the Lorentz equation which indicate that the magnetic field in the plasma sheet focuses selected ions from the plasma sheet boundaries on the neutral sheet are obtained. The kinetic energy of these ions usually exceeds the threshold energy required for the ion tearing mode instability. Two active experiments based on this effect are proposed. Heavy ions injected towards dusk on the plasma sheet boundary would become focused on the neutral sheet and perhaps trigger the ion tearing mode. A boundary perturbation, such as a thermal chemical release, that locally enhances the boundary turbulence level could be introduced, causing sufficient ksq = 1 ions to be focused on the neutral sheet to trigger the ion tearing mode.

  13. Circular Dichroism is Sensitive to Monovalent Cation Binding in Monensin Complexes.

    Science.gov (United States)

    Nedzhib, Ahmed; Kessler, Jiří; Bouř, Petr; Gyurcsik, Béla; Pantcheva, Ivayla

    2016-05-01

    Monensin is a natural antibiotic that exhibits high affinity to certain metal ions. In order to explore its potential in coordination chemistry, circular dichroism (CD) spectra of monensic acid A (MonH) and its derivatives containing monovalent cations (Li(+) , Na(+) , K(+) , Rb(+) , Ag(+) , and Et4 N(+) ) in methanolic solutions were measured and compared to computational models. Whereas the conventional CD spectroscopy allowed recording of the transitions down to 192 nm, synchrotron radiation circular dichroism (SRCD) revealed other bands in the 178-192 nm wavelength range. CD signs and intensities significantly varied in the studied compounds, in spite of their similar crystal structure. Computational modeling based on the Density Functional Theory (DFT) and continuum solvent model suggests that the solid state monensin structure is largely conserved in the solutions as well. Time-dependent Density Functional Theory (TDDFT) simulations did not allow band-to-band comparison with experimental spectra due to their limited precision, but indicated that the spectral changes were caused by a combination of minor conformational changes upon the monovalent cation binding and a direct involvement of the metal electrons in monensin electronic transitions. Both the experiment and simulations thus show that the CD spectra of monensin complexes are very sensitive to the captured ions and can be used for their discrimination. Chirality 28:420-428, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Analysis and Optimization of Stability of CAS-LIBB Single Ion Microbeam

    Institute of Scientific and Technical Information of China (English)

    XU Mingliang; XU Yongjian; ZHAN Furu; CHEN Bin; CHEN Lianyun; LI Jun; YU Zengliang

    2008-01-01

    Single ion microbeam is the most advanced technology which can emit a single ion for precise localization. A single-ion microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB),Chinese Academy of Sciences (CAS),with a spatial resolutions of about 5 #m.Based on CAS-LIBB microbeam,three key elements affecting the quality of the system axe assessed:the size of beam spot,the energy range and the counting accuracy of implanting ions.Various contributions to the ion beam stability,including the ion source,the terminal voltage of electrostatic accelerator and the components in beam pipeline,are discussed.Analysis shows that the improvement of terminal voltage stability is the most important issue for future optimization of CAS-LIBB facility.Some preliminary investigations and project aimed at optimization and development are proposed as well.

  15. Development of Highly Sensitive Ion Imager Corresponding to Real-Time Readout Having Single-Ion Detectability

    Science.gov (United States)

    Sakamoto, Naoya; Aoyama, Satoshi; Kawahito, Shoji; Yurimoto, Hisayoshi

    2012-07-01

    We designed a new type of stacked complementary metal-oxide-semiconductor active pixel sensor (SCAPS) for charged particles with real-time readout and single-ion detection capabilities. Here we present the characteristics of a new imager, SCAPS-II, which implements a newly devised pixel structure of 504×504 pixels for high sensitivity and a noise-reduction mechanism with analog accumulation capabilities inside the column readout circuits. The sensitivity for ions was estimated to be 150 µV/ion under 10 keV Si+ ion irradiation, which is 5 times greater than that of conventional SCAPS. The noise floor was at the 3 ion level without the noise-reduction mechanism at a frame rate of 0.16 s/frame. The noise reduction mechanism reduced the noise to the 1.7 ion level at 0.3 s/frame with 13 samplings. A combination of the noise-reduction mechanism and a multiple-frame-averaging technique achieved a noise level of 0.3 ions. Single-ion detectability was demonstrated using a combination of the noise-reduction mechanism and the multiple-frame-averaging technique that reduced the noise to the 0.3 ion level with 13 samplings, employing an integration circuit and 50-frame averaging at 14.4 s/frame.

  16. Quantitative Probing of Cu(2+) Ions Naturally Present in Single Living Cells.

    Science.gov (United States)

    Lee, Junho; Lee, Hwa-Rim; Pyo, Jaeyeon; Jung, Youngseob; Seo, Ji-Young; Ryu, Hye Guk; Kim, Kyong-Tai; Je, Jung Ho

    2016-06-01

    Quantitative probing of Cu(2+) ions naturally present in single living cells is realized by developing a quantum-dot-embedded nanowire-waveguide probe. The intracellular Cu(2+) ion concentration is quantified by direct monitoring of photoluminescence quenching during the insertion of the nanowire in a living neuron. The measured intracellular Cu(2+) ion concentration is 3.34 ± 1.04 × 10(-6) m (mean ± s.e.m.) in single hippocampal neurons.

  17. Coupled-cluster calculations of properties of Boron atom as a monovalent system

    CERN Document Server

    Gharibnejad, H

    2015-01-01

    We present relativistic coupled-cluster (CC) calculations of energies, magnetic-dipole hyperfine constants, and electric-dipole transition amplitudes for low-lying states of atomic boron. The trivalent boron atom is computationally treated as a monovalent system. We explore performance of the CC method at various approximations. Our most complete treatment involves singles, doubles and the leading valence triples. The calculations are done using several approximations in the coupled-cluster (CC) method. The results are within 0.2-0.4% of the energy benchmarks. The hyperfine constants are reproduced with 1-2% accuracy.

  18. Creation and recovery of a W(111) single atom gas field ion source.

    Science.gov (United States)

    Pitters, Jason L; Urban, Radovan; Wolkow, Robert A

    2012-04-21

    Tungsten single atom tips have been prepared from a single crystal W(111) oriented wire using the chemical assisted field evaporation and etching method. Etching to a single atom tip occurs through a symmetric structure and leads to a predictable last atom unlike etching with polycrystalline tips. The single atom tip formation procedure is shown in an atom by atom removal process. Rebuilds of single atom tips occur on the same crystalline axis as the original tip such that ion emission emanates along a fixed direction for all tip rebuilds. This preparation method could be utilized and developed to prepare single atom tips for ion source development.

  19. A single strontium Rydberg ion confined in a Paul trap

    CERN Document Server

    Higgins, Gerard; Pokorny, Fabian; Zhang, Chi; Kress, Florian; Maier, Christine; Haag, Johannes; Bodart, Quentin; Lesanovsky, Igor; Hennrich, Markus

    2016-01-01

    Trapped Rydberg ions are a promising new system for quantum information processing. They have the potential to join the precise quantum operations of trapped ions and the strong, long-range interactions between Rydberg atoms. Technically, the ion trap will need to stay active while exciting the ions into the Rydberg state, else the strong Coulomb repulsion will quickly push the ions apart. Thus, a thorough understanding of the trap effects on Rydberg ions is essential for future applications. Here we report the observation of two fundamental trap effects. First, we investigate the interaction of the Rydberg electron with the quadrupolar electric trapping field. This effect leads to Floquet sidebands in the spectroscopy of Rydberg D-states whereas Rydberg S-states are unaffected due to their symmetry. Second, we report on the modified trapping potential in the Rydberg state compared to the ground state which results from the strong polarizability of the Rydberg ion. We observe the resultant energy shifts as a ...

  20. Focusing a single ion beam into a 5$\\mu$m spot

    CERN Document Server

    Schnitzler, Wolfgang; Fickler, Robert; Schmidt-Kaler, Ferdinand; Singer, Kilian

    2009-01-01

    We focus down an ion beam consisting of single $^{40}\\mathrm{Ca}^+$ ions to a spot size of a few $\\mu$m using an einzel-lens. Starting from a segmented linear Paul trap, we have implemented a procedure which allows us to deterministically load a predetermined number of ions by using the potential shaping capabilities of our ion trap. For single ion loading, an efficiency of 96.7(7)% has been achieved. These ions are then deterministically extracted out of the trap and focused down to a 1$\\sigma$-spot radius of $(4.62\\pm1.25)$\\mu$m at a distance of 257mm from the trap center. Compared to the 1$\\sigma$-spot radius of 83$(^{+8}_{-3})\\mu$m without ion optics, the einzel-lens is focusing down the single ion beam by a factor of 18. Due to the small beam divergence and narrow velocity distribution of our ion source, chromatic and spherical aberration at the einzel-lens is vastly reduced, presenting a promising starting point for focusing single ions on their way to a prospective substrate.

  1. High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

    CERN Document Server

    Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

    2003-01-01

    A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

  2. Influence of chemical microstructure of single-ion polymeric electrolyte membranes on performance of lithium-ion batteries.

    Science.gov (United States)

    Zhang, Yunfeng; Rohan, Rupesh; Cai, Weiwei; Xu, Guodong; Sun, Yubao; Lin, An; Cheng, Hansong

    2014-10-22

    A novel protocol to generate and control porosity in polymeric structures is presented for fabrication of single ion polymer electrolyte (SIPE) membranes for lithium ion batteries. A series of SIPEs with varying ratios of aliphatic and aromatic segments was successfully synthesized and subsequently blended with PVDF-HFP to fabricate membranes of various sizes of pores. The membranes were characterized using techniques including SEM, solvent uptake capacity measurement and ionic conductivity. We demonstrate that appropriate membrane porosity enhances ionic conductivity, reduces interfacial resistance between electrodes and electrolyte and ultimately boosts performance of Li-ion batteries. The implication of the structure-performance relationship for battery design is discussed.

  3. Ionic force field optimization based on single-ion and ion-pair solvation properties: going beyond standard mixing rules.

    Science.gov (United States)

    Fyta, Maria; Netz, Roland R

    2012-03-28

    Using molecular dynamics (MD) simulations in conjunction with the SPC/E water model, we optimize ionic force-field parameters for seven different halide and alkali ions, considering a total of eight ion-pairs. Our strategy is based on simultaneous optimizing single-ion and ion-pair properties, i.e., we first fix ion-water parameters based on single-ion solvation free energies, and in a second step determine the cation-anion interaction parameters (traditionally given by mixing or combination rules) based on the Kirkwood-Buff theory without modification of the ion-water interaction parameters. In doing so, we have introduced scaling factors for the cation-anion Lennard-Jones (LJ) interaction that quantify deviations from the standard mixing rules. For the rather size-symmetric salt solutions involving bromide and chloride ions, the standard mixing rules work fine. On the other hand, for the iodide and fluoride solutions, corresponding to the largest and smallest anion considered in this work, a rescaling of the mixing rules was necessary. For iodide, the experimental activities suggest more tightly bound ion pairing than given by the standard mixing rules, which is achieved in simulations by reducing the scaling factor of the cation-anion LJ energy. For fluoride, the situation is different and the simulations show too large attraction between fluoride and cations when compared with experimental data. For NaF, the situation can be rectified by increasing the cation-anion LJ energy. For KF, it proves necessary to increase the effective cation-anion Lennard-Jones diameter. The optimization strategy outlined in this work can be easily adapted to different kinds of ions.

  4. Effects of monovalent cations on folding kinetics of G-quadruplexes.

    Science.gov (United States)

    You, Jing; Li, Hui; Lu, Xi-Ming; Li, Wei; Wang, Peng-Ye; Dou, Shuo-Xing; Xi, Xu-Guang

    2017-08-31

    G-quadruplexes are special structures existing at the ends of human telomeres, the folding kinetics of which are essential for their functions, such as in the maintenance of genome stability and the protection of chromosome ends. In the present study, we investigated the folding kinetics of G-quadruplex in different monovalent cation environments and determined the detailed kinetic parameters for Na(+)- and K(+)-induced G-quadruplex folding, and for its structural transition from the basket-type Na(+) form to the hybrid-type K(+) form. More interestingly, although Li(+) was often used in previous studies of G-quadruplex folding as a control ion supposed to have no effect, we have found that Li(+) can actually influence the folding kinetics of both Na(+)- and K(+)-induced G-quadruplexes significantly and in different ways, by changing the folding fraction of Na(+)-induced G-quadruplexes and greatly increasing the folding rates of K(+)-induced G-quadruplexes. The present study may shed new light on the roles of monovalent cations in G-quadruplex folding and should be useful for further studies of the underlying folding mechanism. © 2017 The Author(s).

  5. Note: Single ion imaging and fluorescence collection with a parabolic mirror trap

    Science.gov (United States)

    Chou, Chen-Kuan; Auchter, Carolyn; Lilieholm, Jennifer; Smith, Kevin; Blinov, Boris

    2017-08-01

    Efficient fluorescence collection is the most challenging part in remote entangled ion qubit state generation. To address this issue, we developed an ion trap consisting of a reflective parabolic surface and a needle electrode. This parabolic trap design covers a solid angle of 2π steradians and allows precise ion placement at the focal point of the parabola. We measured (39 ± 3)% fluorescence collection from a single ion with this trap and analyzed the mirror optical performance. We observed single ion image spot size of 3.4 times diffraction limit, improved to 2.8 times diffraction limit with the help of an external deformable mirror. The micromotion of the ion is determined to be the limiting factor, and the result is consistent with theoretical calculation.

  6. Development of heavy-ion irradiation technique for single-event in semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Norio; Akutsu, Takao; Matsuda, Sumio [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan). Tsukuba Space Center; Naitoh, Ichiro; Itoh, Hisayoshi; Agematsu, Takashi; Kamiya, Tomihiro; Nashiyama, Isamu

    1997-03-01

    Heavy-ion irradiation technique has been developed for the evaluation of single-event effects on semiconductor devices. For the uniform irradiation of high energy heavy ions to device samples, we have designed and installed a magnetic beam-scanning system in a JAERI cyclotron beam course. It was found that scanned area was approximately 4 x 2 centimeters and that the deviation of ion fluence from the average value was less than 7%. (author)

  7. A dense transparent polymeric single ion conductor for lithium ion batteries with remarkable long-term stability

    Science.gov (United States)

    Pan, Qiyun; Chen, Yazhou; Zhang, Yunfeng; Zeng, Danli; Sun, Yubao; Cheng, Hansong

    2016-12-01

    We report an outstanding electrochemical performance of a gel type lithium ion battery with long cycle life enabled by a dense transparent polymeric single ion conductor. The polymer electrolyte was synthesized by a side chain grafting method with 4-amino-4'-trifluoromethyl bis(benzene sulfonyl)imide grafted on side chains of poly(ethylene-alt-maleic anhydride) with a grafting ratio of 50%. Blending lithiated iononmers with poly(vinylidene fluoride-co-hexafluoropropylene) via a solution cast method results in a dense transparent film. The fabricated blend polymer electrolyte film has an ionic conductivity of 0.104 mS cm-1 at room temperature, a tensile strength of 15.5 MPa and percent elongation at break of 5%. A gel type single ion conductive polymeric lithium ion battery was assembled using the blend film as the separator as well as the electrolyte, LiFePO4/C mixed with ionomers as the cathode and a lithium foil as the anode. The battery delivers a reversible discharge capacity of 100 mAh g-1 at 1 C under room temperature for 1000 cycles without obvious decay. The stable cyclic imide and comb-like structure of the polymer is largely responsible for the excellent battery performance. The side chain grafted single ion conducting polymer electrolyte is well suited for large-scale production.

  8. On the single-ion Magnetic Anisotropy of the Rare-Earth Metals

    DEFF Research Database (Denmark)

    Kolmakova, N.P.; Tishin, A.M.; Bohr, Jakob

    1996-01-01

    The temperature dependences of the single-ion magnetic anisotropy constants for Tb and Dy metals are calculated in terms of the multipole moments of the rare-earth ions utilizing the available crystal-field parameters. The results are compared with the existing experimental data....

  9. Effect of strontium ions on the early formation of biomimetic apatite on single crystalline rutile

    Science.gov (United States)

    Lindahl, Carl; Engqvist, Håkan; Xia, Wei

    2013-02-01

    Single crystalline rutile is a good model to investigate the growth mechanism of hydroxyapatite on bioactive Ti surfaces. Previous studies have shown the difference on different crystalline rutile faces in the early stage and during the growth of HAp crystals from simulated body fluids. It is known that the biological apatite crystal is an ion-substituted apatite. Ion substitution will influence the HAp crystal growth and morphology. In the present study, the effect of strontium ions on the adsorption of Ca and phosphate ions on three different faces of single crystalline rutile substrates has been investigated. The ion adsorption is the crucial step in the nucleation of HAp crystals on specific surfaces. Single crystalline rutile surfaces ((1 1 0), (1 0 0) and (0 0 1)) were soaked in phosphate buffer solutions containing calcium and strontium ions for different time periods. The results showed that the adsorption of Sr, Ca and P is faster on the (1 1 0) surface than on the (1 0 0) and (0 0 1) surfaces. Almost same amount of Sr ion was adsorbed on the surfaces compared to the adsorption of Ca ion. Strontium ion influenced the biological apatite formation in the early stage in this study.

  10. Lattice location of platinum ions implanted into single crystal zirconia and their annealing behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Cao, D.X. [Royal Melbourne Inst. of Tech., VIC (Australia); Sood, D.K. [Academia Sinica, Shanghai, SH (China). Shanghai Inst. of Nuclear Research; Brown, I.G. [Lawrence Berkeley Lab., CA (United States)

    1993-12-31

    Single crystal samples of (100) oriented cubic zirconia stabilised with 9.5 mol % yttria were implanted with platinum ions, using a metal vapour vacuum arc (MEVVA) high current ion implanter, to a nominal dose of 1x10{sup 17} ions/cm{sup 2}. The implanted samples were annealed isothermally in air ambient at 1200 deg C, from 1-24 hours. Rutherford Backscattering Spectrometry and Channeling (RBSC) of 2 MeV He ions are employed to determine depth distributions of ion damage, Pt ions and substitutionality of Pt ions before and after annealing. The damage behaviour, Pt migration and lattice location are discussed in terms of metastable phase formation and solid solubility considerations. 7 refs., 3 figs.

  11. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms.

  12. Single-ion polymer electrolyte membranes enable lithium-ion batteries with a broad operating temperature range.

    Science.gov (United States)

    Cai, Weiwei; Zhang, Yunfeng; Li, Jing; Sun, Yubao; Cheng, Hansong

    2014-04-01

    Conductive processes involving lithium ions are analyzed in detail from a mechanistic perspective, and demonstrate that single ion polymeric electrolyte (SIPE) membranes can be used in lithium-ion batteries with a wide operating temperature range (25-80 °C) through systematic optimization of electrodes and electrode/electrolyte interfaces, in sharp contrast to other batteries equipped with SIPE membranes that display appreciable operability only at elevated temperatures (>60 °C). The performance is comparable to that of batteries using liquid electrolyte of inorganic salt, and the batteries exhibit excellent cycle life and rate performance. This significant widening of battery operation temperatures coupled with the inherent flexibility and robustness of the SIPE membranes makes it possible to develop thin and flexible Li-ion batteries for a broad range of applications.

  13. Nondestructive photon detection using a single rare-earth ion coupled to a photonic cavity

    Science.gov (United States)

    O'Brien, Chris; Zhong, Tian; Faraon, Andrei; Simon, Christoph

    2016-10-01

    We study the possibility of using single rare-earth ions coupled to a photonic cavity with high cooperativity for performing nondestructive measurements of photons, which would be useful for global quantum networks and photonic quantum computing. We calculate the achievable fidelity as a function of the parameters of the rare-earth ion and photonic cavity, which include the ion's optical and spin dephasing rates, the cavity linewidth, the single-photon coupling to the cavity, and the detection efficiency. We suggest a promising experimental realization using current state-of-the-art technology in Nd:YVO4.

  14. One single trapped and laser cooled radium ion: Towards an all-optical atomic clock

    Energy Technology Data Exchange (ETDEWEB)

    Versolato, Oscar; Wansbeek, Lotje; Willmann, Lorenz; Timmermans, Rob; Jungmann, Klaus [KVI, University of Groningen (Netherlands)

    2008-07-01

    One single trapped radium ion is an ideal candidate for an all-optical frequency standard (*clock*). This system provides a long coherence time and tractable systematics. If the ion is laser cooled to the Lamb-Dicke regime, first order Doppler shifts are eliminated. Ultra-narrow transitions in radium ions provide an excellent basis for such a high stability clock, using commercially available semiconductor lasers in the visible regime. In certain odd isotopes of radium, the nuclear electric quadrupole shift is absent. Further, the radium ion is an excellent candidate for a high sensitivity experiment to search for a time variation of the finestructure constant.

  15. A simple and rapid method for high-resolution visualization of single-ion tracks

    Directory of Open Access Journals (Sweden)

    Masaaki Omichi

    2014-11-01

    Full Text Available Prompt determination of spatial points of single-ion tracks plays a key role in high-energy particle induced-cancer therapy and gene/plant mutations. In this study, a simple method for the high-resolution visualization of single-ion tracks without etching was developed through the use of polyacrylic acid (PAA-N, N’-methylene bisacrylamide (MBAAm blend films. One of the steps of the proposed method includes exposure of the irradiated films to water vapor for several minutes. Water vapor was found to promote the cross-linking reaction of PAA and MBAAm to form a bulky cross-linked structure; the ion-track scars were detectable at a nanometer scale by atomic force microscopy. This study demonstrated that each scar is easily distinguishable, and the amount of generated radicals of the ion tracks can be estimated by measuring the height of the scars, even in highly dense ion tracks. This method is suitable for the visualization of the penumbra region in a single-ion track with a high spatial resolution of 50 nm, which is sufficiently small to confirm that a single ion hits a cell nucleus with a size ranging between 5 and 20 μm.

  16. A simple and rapid method for high-resolution visualization of single-ion tracks

    Energy Technology Data Exchange (ETDEWEB)

    Omichi, Masaaki [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Center for Collaborative Research, Anan National College of Technology, Anan, Tokushima 774-0017 (Japan); Choi, Wookjin; Sakamaki, Daisuke; Seki, Shu, E-mail: seki@chem.eng.osaka-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Tsukuda, Satoshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Sugimoto, Masaki [Japan Atomic Energy Agency, Takasaki Advanced Radiation Research Institute, Gunma, Gunma 370-1292 (Japan)

    2014-11-15

    Prompt determination of spatial points of single-ion tracks plays a key role in high-energy particle induced-cancer therapy and gene/plant mutations. In this study, a simple method for the high-resolution visualization of single-ion tracks without etching was developed through the use of polyacrylic acid (PAA)-N, N’-methylene bisacrylamide (MBAAm) blend films. One of the steps of the proposed method includes exposure of the irradiated films to water vapor for several minutes. Water vapor was found to promote the cross-linking reaction of PAA and MBAAm to form a bulky cross-linked structure; the ion-track scars were detectable at a nanometer scale by atomic force microscopy. This study demonstrated that each scar is easily distinguishable, and the amount of generated radicals of the ion tracks can be estimated by measuring the height of the scars, even in highly dense ion tracks. This method is suitable for the visualization of the penumbra region in a single-ion track with a high spatial resolution of 50 nm, which is sufficiently small to confirm that a single ion hits a cell nucleus with a size ranging between 5 and 20 μm.

  17. Influence of heavy ion flux on single event effect testing in memory devices

    Science.gov (United States)

    Luo, Jie; Liu, Jie; Sun, Youmei; Hou, Mingdong; Xi, Kai; Liu, Tianqi; Wang, Bin; Ye, Bing

    2017-09-01

    The natural space presents a particle flux variable environment and choosing a suitable flux value for ground-based single event experiments is an unresolved problem so far. In this work, various types of memory devices have been tested over the ion flux range from 10 to 105 ions/(cm2·s) using different ions covering LET from 10.1 to 99.8 MeV·cm2/mg. It was found that for most devices the error rates of single event upsets are affected by the applied flux value. And the effect involving flux becomes prominent as it is increased above 103 ions/(cm2·s). Different devices behave differently as the flux is increased and the flux effect depends strongly on the LET of the impinging ions. The results concluded in this experiment are discussed in detail and recommendations for choosing appropriate experimental flux are given.

  18. Network type sp3 boron-based single-ion conducting polymer electrolytes for lithium ion batteries

    Science.gov (United States)

    Deng, Kuirong; Wang, Shuanjin; Ren, Shan; Han, Dongmei; Xiao, Min; Meng, Yuezhong

    2017-08-01

    Electrolytes play a vital role in modulating lithium ion battery performance. An outstanding electrolyte should possess both high ionic conductivity and unity lithium ion transference number. Here, we present a facile method to fabricate a network type sp3 boron-based single-ion conducting polymer electrolyte (SIPE) with high ionic conductivity and lithium ion transference number approaching unity. The SIPE was synthesized by coupling of lithium bis(allylmalonato)borate (LiBAMB) and pentaerythritol tetrakis(2-mercaptoacetate) (PETMP) via one-step photoinitiated in situ thiol-ene click reaction in plasticizers. Influence of kinds and content of plasticizers was investigated and the optimized electrolytes show both outstanding ionic conductivity (1.47 × 10-3 S cm-1 at 25 °C) and high lithium transference number of 0.89. This ionic conductivity is among the highest ionic conductivity exhibited by SIPEs reported to date. Its electrochemical stability window is up to 5.2 V. More importantly, Li/LiFePO4 cells with the prepared single-ion conducting electrolytes as the electrolyte as well as the separator display highly reversible capacity and excellent rate capacity under room temperature. It also demonstrates excellent long-term stability and reliability as it maintains capacity of 124 mA h g-1 at 1 C rate even after 500 cycles without obvious decay.

  19. The method and equipment for the investigation of ions orienting transmission through thin single crystals

    CERN Document Server

    Soroka, V Y; Maznij, Y O

    2003-01-01

    A new approach is proposed to solve the task of angular distribution measurement of intensity strongly differentiated ions fluxes. Channeling effect makes this problem a regular feature of experimental study of ions orientating transmission through thin single crystals. The approach is based on the use of ions additional scattering by an amorphous (polycrystalline) target after passing through single crystal. The additional target manipulator is joined with the principal target chamber equipment with three-axis goniometer. The manipulator allows to move an additional target in the vicinity of the accelerator beam within the limits of +- 3 sup 0 in all directions and allows to measure the angular distribution of scattered ions with the accuracy of 1 min. The method and equipment were tested at the single ended electrostatic accelerator (EG-5) using a proton beam. At present the measurements have been resumed at the tandem accelerator (EG-10) of the Institute for Nuclear Research of the Academy of Sciences of U...

  20. High-energy heavy ion testing of VLSI devices for single event upsets and latch up

    Indian Academy of Sciences (India)

    S B Umesh; S R Kulkarni; R Sandhya; G R Joshi; R Damle; M Ravindra

    2005-08-01

    Several very large scale integrated (VLSI) devices which are not available in radiation hardened version are still required to be used in spacecraft systems. Thus these components need to be tested for highenergy heavy ion irradiation to find out their tolerance and suitability in specific space applications. This paper describes the high-energy heavy ion radiation testing of VLSI devices for single event upset (SEU) and single event latch up (SEL). The experimental set up employed to produce low flux of heavy ions viz. silicon (Si), and silver (Ag), for studying single event effects (SEE) is briefly described. The heavy ion testing of a few VLSI devices is performed in the general purpose scattering chamber of the Pelletron facility, available at Nuclear Science Centre, New Delhi. The test results with respect to SEU and SEL are discussed.

  1. Ferric and cupric ions requirement for DNA single-strand breakage by H2O2.

    Science.gov (United States)

    Tachon, P

    1989-01-01

    Hydrogen peroxide (H2O2), was able to nick the replicative form of the phage fd, without the addition of a reducing agent or of a metal. This DNA single-strand breakage decreased with an increase of the ionic strength, suggesting that H2O2 reacted with traces of metal bound to DNA. When cupric of ferric ions were added, the rate of DNA single-strand breakage by H2O2 greatly increased and it was 20-30 times faster with cupric than with ferric ions. The addition of EDTA at an equimolar ratio or in excess of metal prevented partially DNA single-strand cleavage by H2O2 in the presence of ferric ions and completely when cupric ions were used. Superoxide dismutase prevented DNA single-strand breakage by H2O2 and ferric ions. On the contrary, with cupric ions and H2O2, the addition of superoxide dismutase increased the rate of DNA single-strand breakage. That superoxide dismutase was acting catalytically was shown by the loss of its effects after heat inactivation of the enzyme. The results of the present study show that besides its involvement in the Fenton reaction, H2O2 is able to reduce the metal bound to DNA, generating the superoxide anion radical or/and its protonated form, the perhydroxyl radical involved in DNA nicking. On the other hand, the ability of cuprous ions unlike ferrous ions to dismutate the superoxide radical may explain some differences observed between iron and copper in the DNA single-strand breakage by H2O2.

  2. On singlet metastable states, ion flux and ion energy in single and dual frequency capacitively coupled oxygen discharges

    Science.gov (United States)

    Hannesdottir, H.; Gudmundsson, J. T.

    2017-05-01

    We apply particle-in-cell simulations with Monte Carlo collisions to study the influence of the singlet metastable states on the ion energy distribution in single and dual frequency capacitively coupled oxygen discharges. For this purpose, the one-dimensional object-oriented particle-in-cell Monte Carlo collision code oopd1 is used, in which the discharge model includes the following nine species: electrons, the neutrals O(3P) and O{{}2}≤ft({{\\text{X}}3} Σ g-\\right. ), the negative ions O-, the positive ions O+ and O2+ , and the metastables O(1D), O{{}2}≤ft({{\\text{a}}1}{{ Δ }g}\\right) and O2(b{{}1} Σ g+ ). Earlier, we have explored the effects of adding the species O{{}2}≤ft({{\\text{a}}1}{{ Δ }g}\\right. ) and O2(b{{}1} Σ g+ ), and an energy-dependent secondary electron emission yield for oxygen ions and neutrals, to the discharge model. We found that including the two molecular singlet metastable states decreases the ohmic heating and the effective electron temperature in the bulk region (the electronegative core). Here we explore how these metastable states influence dual frequency discharges consisting of a fundamental frequency and the lowest even harmonics. Including or excluding the detachment reactions of the metastables O{{}2}≤ft({{\\text{a}}1}{{ Δ }g}\\right. ) and O2(b{{}1} Σ g+ ) can shift the peak electron temperature from the grounded to the powered electrode or vice versa, depending on the phase difference of the two applied frequencies. These metastable states can furthermore significantly influence the peak of the ion energy distribution for O2+ -ions bombarding the powered electrode, and hence the average ion energy upon bombardment of the electrode, and lower the ion flux.

  3. Most spin-1/2 transition-metal ions do have single ion anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jia; Whangbo, Myung-Hwan, E-mail: hxiang@fudan.edu.cn, E-mail: mike-whangbo@ncsu.edu [Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695 (United States); Koo, Hyun-Joo [Department of Chemistry and Research Institute for Basic Sciences, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Xiang, Hongjun, E-mail: hxiang@fudan.edu.cn, E-mail: mike-whangbo@ncsu.edu [Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433 (China); Kremer, Reinhard K. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2014-09-28

    The cause for the preferred spin orientation in magnetic systems containing spin-1/2 transition-metal ions was explored by studying the origin of the easy-plane anisotropy of the spin-1/2 Cu{sup 2+} ions in CuCl{sub 2}·2H{sub 2}O, LiCuVO{sub 4}, CuCl{sub 2}, and CuBr{sub 2} on the basis of density functional theory and magnetic dipole-dipole energy calculations as well as a perturbation theory treatment of the spin-orbit coupling. We find that the spin orientation observed for these spin-1/2 ions is not caused by their anisotropic spin exchange interactions, nor by their magnetic dipole-dipole interactions, but by the spin-orbit coupling associated with their crystal-field split d-states. Our study also predicts in-plane anisotropy for the Cu{sup 2+} ions of Bi{sub 2}CuO{sub 4} and Li{sub 2}CuO{sub 2}. The results of our investigations dispel the mistaken belief that magnetic systems with spin-1/2 ions have no magnetic anisotropy induced by spin-orbit coupling.

  4. Deterministic delivery of externally cold and precisely positioned single molecular ions

    CERN Document Server

    Leschhorn, G; Schaetz, T

    2011-01-01

    We present the preparation and deterministic delivery of a selectable number of externally cold molecular ions. A laser cooled ensemble of Mg^+ ions subsequently confined in several linear Paul traps inter-connected via a quadrupole guide serves as a cold bath for a single or up to a few hundred molecular ions. Sympathetic cooling embeds the molecular ions in the crystalline structure. MgH^+ ions, that serve as a model system for a large variety of other possible molecular ions, are cooled down close to the Doppler limit and are positioned with an accuracy of one micrometer. After the production process, severely compromising the vacuum conditions, the molecular ion is efficiently transfered into nearly background-free environment. The transfer of a molecular ion between different traps as well as the control of the molecular ions in the traps is demonstrated. Schemes, optimized for the transfer of a specific number of ions, are realized and their efficiencies are evaluated. This versatile source applicable f...

  5. Single electron capture in fast ion-atom collisions

    Science.gov (United States)

    Milojević, Nenad

    2014-12-01

    Single-electron capture cross sections in collisions between fast bare projectiles and heliumlike atomic systems are investigated by means of the four-body boundary-corrected first Born (CB1-4B) approximation. The prior and post transition amplitudes for single charge exchange encompassing symmetric and asymmetric collisions are derived in terms of twodimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. The dielectronic interaction V12 = 1/r12 = 1/|r1 - r2| explicitly appears in the complete perturbation potential Vf of the post transition probability amplitude T+if. An illustrative computation is performed involving state-selective and total single capture cross sections for the p - He (prior and post form) and He2+, Li3+Be4+B5+C6+ - He (prior form) collisions at intermediate and high impact energies. We have also studied differential cross sections in prior and post form for single electron transfer from helium by protons. The role of dynamic correlations is examined as a function of increased projectile energy. Detailed comparisons with the measurements are carried out and the obtained theoretical cross sections are in reasonable agreement with the available experimental data.

  6. Controlling the electromagnetism of single ion by "molecular surgery"

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Controlling and modifying the magnetic property of a single molecule is the frontier for the development of molecular science. With the funding support from NSFC,Scientific Innovation Program of CAS as well as 973 from Ministry of Science and Technology of China, Prof.Jianguo Hou (Member of CAS) and Prof.

  7. Quantum to Classical Transition in a Single-Ion Laser

    CERN Document Server

    Dubin, François; Barros, Helena G; Stute, Andreas; Becher, Christoph; Schmidt, Piet O; Blatt, Rainer

    2010-01-01

    Stimulated emission of photons from a large number of atoms into the mode of a strong light field is the principle mechanism for lasing in "classical" lasers. The onset of lasing is marked by a threshold which can be characterised by a sharp increase in photon flux as a function of external pumping strength. The same is not necessarily true for the fundamental building block of a laser: a single trapped atom interacting with a single optical radiation mode. It has been shown that such a "quantum" laser can exhibit thresholdless lasing in the regime of strong coupling between atom and radiation field. However, although theoretically predicted, a threshold at the single-atom level could not be experimentally observed so far. Here, we demonstrate and characterise a single-atom laser with and without threshold behaviour by changing the strength of atom-light field coupling. We observe the establishment of a laser threshold through the accumulation of photons in the optical mode even for a mean photon number subst...

  8. Fabrication and characterization of a co-planar detector in diamond for low energy single ion implantation

    Science.gov (United States)

    Abraham, J. B. S.; Aguirre, B. A.; Pacheco, J. L.; Vizkelethy, G.; Bielejec, E.

    2016-08-01

    We demonstrate low energy single ion detection using a co-planar detector fabricated on a diamond substrate and characterized by ion beam induced charge collection. Histograms are taken with low fluence ion pulses illustrating quantized ion detection down to a single ion with a signal-to-noise ratio of approximately 10. We anticipate that this detection technique can serve as a basis to optimize the yield of single color centers in diamond. The ability to count ions into a diamond substrate is expected to reduce the uncertainty in the yield of color center formation by removing Poisson statistics from the implantation process.

  9. Ion selectivity of graphene nanopores

    Science.gov (United States)

    Rollings, Ryan C.; Kuan, Aaron T.; Golovchenko, Jene A.

    2016-04-01

    As population growth continues to outpace development of water infrastructure in many countries, desalination (the removal of salts from seawater) at high energy efficiency will likely become a vital source of fresh water. Due to its atomic thinness combined with its mechanical strength, porous graphene may be particularly well-suited for electrodialysis desalination, in which ions are removed under an electric field via ion-selective pores. Here, we show that single graphene nanopores preferentially permit the passage of K+ cations over Cl- anions with selectivity ratios of over 100 and conduct monovalent cations up to 5 times more rapidly than divalent cations. Surprisingly, the observed K+/Cl- selectivity persists in pores even as large as about 20 nm in diameter, suggesting that high throughput, highly selective graphene electrodialysis membranes can be fabricated without the need for subnanometer control over pore size.

  10. Salt Contribution to the Flexibility of Single-stranded Nucleic Acid of Finite Length

    CERN Document Server

    Wang, Feng-Hua; Tan, Zhi-Jie

    2012-01-01

    Nucleic acids are negatively charged macromolecules and their structure properties are strongly coupled to metal ions in solutions. In this paper, the salt effects on the flexibility of single stranded (ss) nucleic acid chain ranging from 12 to 120 nucleotides are investigated systematically by the coarse grained Monte Carlo simulations where the salt ions are considered explicitly and the ss chain is modeled with the virtual bond structural model. Our calculations show that, the increase of ion concentration causes the structural collapse of ss chain and multivalent ions are much more efficient in causing such collapse, and trivalent and small divalent ions can both induce more compact state than a random relaxation state. We found that monovalent, divalent and trivalent ions can all overcharge ss chain, and the dominating source for such overcharging changes from ion exclusion volume effect to ion Coulomb correlations. In addition, the predicted Na and Mg dependent persistence length lp of ss nucleic acid a...

  11. A single-chip telescope for heavy-ion identification

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, G.; Barlini, S.; Bardelli, L.; Carboni, S.; Bini, M.; Poggi, G.; Stefanini, A.A. [Universita di Firenze, Dipartimento di Fisica, Sesto Fiorentino (Italy); Sezione di Firenze, INFN, Sesto Fiorentino (Italy); Le Neindre, N.; Bougault, R.; Lopez, O.; Vient, E. [ENSICAEN et Universite de Caen, LPC, IN1P3-CNRS, Caen-Cedex (France); Borderie, B.; Edelbruck, P.; Rivet, M.F.; Seredov, V. [Universite Paris-Sud 11, Institut de Physique Nucleaire, CNRS/IN2P3, Orsay cedex (France); Casini, G.; Olmi, A.; Piantelli, S. [Sezione di Firenze, INFN, Sesto Fiorentino (Italy); Baiocco, G. [ENSICAEN et Universite de Caen, LPC, IN1P3-CNRS, Caen-Cedex (France); INFN, Bologna (Italy); University of Bologna, Bologna (Italy); Berjillos, R.; Duenas, J.A.; Martel, I. [FCCEE Universidad de Huelva, Departamento de Fisica Aplicada, Huelva (Spain); Bonnet, E.; Chbihi, A. [CEA/DSM-CNRS/IN2P3, GANIL, F-14076, Caen cedex (France); Bruno, M.; Morelli, L. [INFN, Bologna (Italy); University of Bologna, Bologna (Italy); Cruceru, I.; Petrascu, H. [' ' Horia Hulubei' ' National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Degerlier, M.; Gramegna, F.; Kravchuk, V.L.; Marchi, T. [INFN-LNL Legnaro, Legnaro (Padova) (Italy); Falorsi, M. [Universita di Firenze, Dipartimento di Fisica, Sesto Fiorentino (Italy); Galichet, E. [Universite Paris-Sud 11, Institut de Physique Nucleaire, CNRS/IN2P3, Orsay cedex (France); Conservatoire National des Arts et Metiers, Paris Cedex 03 (France); Kordyasz, A. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Kozik, T. [Institute of Nuclear Physics IFJ-PAN, Jagiellonian University, Krakow (Poland); Parlog, M. [ENSICAEN et Universite de Caen, LPC, IN1P3-CNRS, Caen-Cedex (France); ' ' Horia Hulubei' ' National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Rosato, E.; Vigilante, M. [Universita di Napoli Federico II, Dipartimento di Scienze Fisiche (Italy); INFN, Napoli (Italy); Collaboration: For the FAZIA Collaboration

    2012-11-15

    A {Delta}E-E telescope exploiting a single silicon chip for both {Delta}E measurement and scintillation light collection has been tested. It is a Si - CsI (Tl) telescope tailored for mass identification of light charged particles and intermediate mass fragments. A procedure based on two different shaping filters allows for extraction of the {Delta}E-E information from the single silicon signal. The quality of the obtained fragment identification is expressed in terms of a figure of merit and compared to that of a standard {Delta}E-E telescope. The presented configuration could be a good candidate for the basic cell of a large solid angle array of {Delta}E-E telescopes, given the reduction in complexity and cost of the front-end electronics. (orig.)

  12. A single-chip telescope for heavy-ion identification

    Science.gov (United States)

    Pasquali, G.; Barlini, S.; Bardelli, L.; Carboni, S.; Le Neindre, N.; Bini, M.; Borderie, B.; Bougault, R.; Casini, G.; Edelbruck, P.; Olmi, A.; Poggi, G.; Rivet, M. F.; Stefanini, A. A.; Baiocco, G.; Berjillos, R.; Bonnet, E.; Bruno, M.; Chbihi, A.; Cruceru, I.; Degerlier, M.; Dueñas, J. A.; Falorsi, M.; Galichet, E.; Gramegna, F.; Kordyasz, A.; Kozik, T.; Kravchuk, V. L.; Lopez, O.; Marchi, T.; Martel, I.; Morelli, L.; Parlog, M.; Petrascu, H.; Piantelli, S.; Rosato, E.; Seredov, V.; Vient, E.; Vigilante, M.

    2012-11-01

    A Δ E- E telescope exploiting a single silicon chip for both Δ E measurement and scintillation light collection has been tested. It is a Si - CsI (Tl) telescope tailored for mass identification of light charged particles and intermediate mass fragments. A procedure based on two different shaping filters allows for extraction of the Δ E- E information from the single silicon signal. The quality of the obtained fragment identification is expressed in terms of a figure of merit and compared to that of a standard Δ E- E telescope. The presented configuration could be a good candidate for the basic cell of a large solid angle array of Δ E- E telescopes, given the reduction in complexity and cost of the front-end electronics.

  13. Swift heavy ion irradiation of CaF2 - from grooves to hillocks in a single ion track

    Science.gov (United States)

    Gruber, Elisabeth; Salou, Pierre; Bergen, Lorenz; El Kharrazi, Mourad; Lattouf, Elie; Grygiel, Clara; Wang, Yuyu; Benyagoub, Abdenacer; Levavasseur, Delphine; Rangama, Jimmy; Lebius, Henning; Ban-d'Etat, Brigitte; Schleberger, Marika; Aumayr, Friedrich

    2016-10-01

    A novel form of ion-tracks, namely nanogrooves and hillocks, are observed on CaF2 after irradiation with xenon and lead ions of about 100 MeV kinetic energy. The irradiation is performed under grazing incidence (0.3°-3°) which forces the track to a region in close vicinity to the surface. Atomic force microscopy imaging of the impact sites with high spatial resolution reveals that the surface track consists in fact of three distinct parts: each swift heavy ion impacting on the CaF2 surface first opens a several 100 nm long groove bordered by a series of nanohillocks on both sides. The end of the groove is marked by a huge single hillock and the further penetration of the swift projectile into deeper layers of the target is accompanied by a single protrusion of several 100 nm in length slowly fading until the track vanishes. By comparing experimental data for various impact angles with results of a simulation, based on a three-dimensional version of the two-temperature-model (TTM), we are able to link the crater and hillock formation to sublimation and melting processes of CaF2 due to the local energy deposition by swift heavy ions.

  14. Current progress of the biological single-ion microbeam at FUDAN.

    Science.gov (United States)

    Wang, X F; Li, J Q; Wang, J Z; Zhang, J X; Liu, A; He, Z J; Zhang, W; Zhang, B; Shao, C L; Shi, L Q

    2011-08-01

    A biological microbeam for precisely positioned single-ion/single cell irradiation is built in the Institute of Modern Physics in Fudan University, Shanghai, China, based on the tandem accelerator (2 × 3MV) in the laboratory. In this paper, the developing progress of the FUDAN microbeam is reported, including the newly constructed beam line, the microbeam collimator, the ion detection system, and the cell-imaging and targeting systems. Statistical models are proposed for evaluating the spatial resolution and dosage precision of the microbeam. By taking the collimated ions as a Gaussian beam, the spatial resolution can be evaluated by the full width at half maximum of the 2-D Gaussian distribution, which is determined by fitting the proportions of peripheral pits outside specific radii in the pit clusters etched on ion track detectors to a 2-D Gaussian distribution. In the preset hitting of defined ion number, by taking the real delivered number of ions as an independent identically distributed random variable (iidrv), according to the Law of Large Numbers and Central Limit Theorem, the expected value μ and standard deviation σ of the real delivered ion number in a preset N-ion hitting can be determined by approaching the normal distribution of N (μ, σ (2)/n) with the proportions of the mean counts of pits in multiple pit clusters on ion track detectors. By the values of μ, σ and additional assumptions, statistical dosage precision evaluations can be made on the preset hitting. From the linear fit curve of μ(N) and the power function fit curve of σ(N) on different preset ion numbers, characteristic factors k, b, A, p can be extracted for a precision evaluation independent of the specific preset ion number.

  15. Optical and magnetic properties of nitrogen ion implanted MgO single crystal

    Institute of Scientific and Technical Information of China (English)

    Liu Chun-Ming; Gu Hai-Quan; Xiang Xia; Zhang Yan; Jiang Yong; Chen Meng; Zu Xiao-Tao

    2011-01-01

    The microstructure, optical property and magnetism of nitrogen ion implanted single MgO crystals are studied.A parallel investigation is also performed in an iron ion implanted single MgO sample as a reference. Large structural,optical and magnetic differences are obtained between the nitrogen and iron implanted samples. Room temperature ferromagnetism with a fairly large coercivity field of 300 Oe (1 Oe=79.5775 A/m), a remanence of 38% and a slightly changed optical absorption is obtained in the sample implanted using nitrogen with a dose of 1×1018 ions/cm2. Transition metal contamination and defects induced magnetism can be excluded when compared with those of the iron ion implanted sample, and the nitrogen doping is considered to be the main origin of ferromagnetism.

  16. Observation of single Ca{sup +} ions for trace isotope analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Y. [Department of Quantum Engineering and Systems Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)], E-mail: yhashi@lyman.q.t.u-tokyo.ac.jp; Matsuoka, L.; Nagamoto, D. [Department of Quantum Engineering and Systems Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Hasegawa, S. [Department of Quantum Engineering and Systems Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)], E-mail: hasegawa@q.t.u-tokyo.ac.jp

    2008-06-15

    We developed an ion trap - laser cooling system for observing the laser induced fluorescence (LIF) of a single ion, in the view of utilizing it for the trace isotope analysis of Ca. We observed stepwise LIF signals, which correspond to the numbers of trapped {sup 40}Ca{sup +} ions ({sup 40}Ca/Ca = 96.9%). The detection efficiency was evaluated and the observation of single ions demonstrated the experimental feasibility of trace isotope analysis. Furthermore, as the next step towards trace isotope analysis, we report observation of the even calcium isotopes, {sup 44}Ca ({sup 44}Ca/Ca = 2.09%) and {sup 48}Ca ({sup 48}Ca/Ca = 0.187%), without the use of a selective loading method.

  17. Polarized spectral complexes of optical functions of monovalent mercury iodide

    Science.gov (United States)

    Sobolev, V. V.; Sobolev, V. Val.; Anisimov, D. V.

    2015-12-01

    Spectral complexes of optical functions of monovalent mercury iodide Hg2I2 were determined for E ⊥ c and E || c polarizations in the range from 2 to 5.5 eV at 4.2 K. The permittivity and characteristic electron energy loss spectra were expanded in simple components with the determination of their main parameters, including the energy of the maximum and the oscillator strength. The calculations were performed based on known reflectance spectra. Computer programs based on Kramers-Kronig relations and the improved parameter-free method of Argand diagrams were used.

  18. Effect of 120 MeV Ag{sup 9+} ion irradiation of YCOB single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Arun Kumar, R., E-mail: rarunpsgtech@yahoo.com [Crystal Growth Centre, Anna University, Chennai 600 025 (India); Department of Basic Sciences - Physics Division, PSG College of Technology, Coimbatore 641 004 (India); Dhanasekaran, R. [Crystal Growth Centre, Anna University, Chennai 600 025 (India)

    2012-09-15

    Single crystals of yttrium calcium oxy borate (YCOB) grown from boron-tri-oxide flux were subjected to swift heavy ion irradiation using silver Ag{sup 9+} ions from the 15 UD Pelletron facility at Inter University Accelerator Center, New Delhi. The crystals were irradiated at 1 Multiplication-Sign 10{sup 13}, 5 Multiplication-Sign 10{sup 13} and 1 Multiplication-Sign 10{sup 14} ions/cm{sup 2} fluences at room temperature and with 5 Multiplication-Sign 10{sup 13} ions/cm{sup 2} fluence at liquid nitrogen temperature. The pristine and the irradiated samples were characterized by glancing angle X-ray diffraction, UV-Vis-NIR and photoluminescence studies. From the characterization studies performed on the samples, it is inferred that the crystals irradiated at liquid nitrogen temperature had fewer defects compared to the crystals irradiated at room temperature and the defects increased when the ion fluence was increased at room temperature.

  19. A Study of Single-Pass Ion Effects at the ALS.

    Science.gov (United States)

    Byrd, J. M.; Thomson, J.; Chao, A. W.; Heifets, S.; Minty, M. G.; Seeman, J. T.; Stupakov, G. V.; Zimmermann, F.; Raubenheimer, T. O.

    1997-05-01

    We report studies of single-pass ion effects performed at the Advanced Light Source (ALS). To enhance the ion effects, the ALS vacuum pressure was intentionally increased to about 50 nTorr by a remotely controlled inflow of helium gas. At this pressure we observe, on a synchrotron light monitor, a blowup of the vertical beam size for as few as 10 consecutive bunches (97% empty ring). No blow-up is observed when a single bunch is stored in the ring. For gaps in the fill pattern of 25 and 50%, where conventional ion trapping is not expected, we observe an approximate doubling of the vertical emittance. Nonuniform beam loss for vertical beam scraping indicates that the tail of the bunch train is driven by the instabilty more than the head. Therefore, the blow-up appears to be caused by a single-pass ion effect. In some but not all studies we also observed coherent vertical betatron oscillations, as evidenced by a pattern of lower betatron sidebands, whose envelope peaked around the estimated ion frequency. Both the beam-size blow-up and the betatron sidebands are consistent with theoretical predictions for the `fast beam-ion instability'.

  20. Quantum ion-acoustic oscillations in single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Khan, S.A. [Kyoto Univ., Katsura (Japan). Graduate School of Engineering; Quaid-i-Azam Univ., Islamabad (Pakistan). National Centre for Physics; Iqbal, Z. [University of Management and Technology, Sialkot (Pakistan); Wazir, Z. [Riphah International Univ., Islamabad (Pakistan). Dept. of Basic Sciences; Rehman, Aman ur [Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad (Pakistan)

    2016-08-01

    Quantum ion-acoustic oscillations in single-walled carbon nanotubes are studied by employing a quantum hydrodynamics model. The dispersion equation is obtained by Fourier transformation, which exhibits the existence of quantum ion-acoustic wave affected by change of density balance due to presence of positive or negative heavy species as stationary ion clusters and wave potential at equilibrium. The numerical results are presented, and the role of quantum degeneracy, nanotube geometry, electron exchange-correlation effects, and concentration and polarity of heavy species on wave dispersion is pointed out for typical systems of interest.

  1. Energy distribution of metal and noble gas ions traversing single-crystal copper films

    Science.gov (United States)

    Isakhanov, Z. A.

    2012-09-01

    A comparative investigation of the energy distribution of ions that traversed single-crystal cooper films reveals that the energy loss of channeled and nonchanneled particles depends not only on the mass but also on the radius of bombarding ions. It is established that the energy spectra of transmitted ions are highly sensitive to a change in the composition and structure of the films. From the change in these spectra, one can estimate the degree of disordering in thin films under various applied forces.

  2. Atomic parity violation in one single trapped radium ion as a probe of electroweak running

    Energy Technology Data Exchange (ETDEWEB)

    Wansbeek, Lotje; Versolato, Oscar; Willmann, Lorenz; Timmermans, Rob; Jungmann, Klaus [KVI, University of Groningen (Netherlands)

    2008-07-01

    In a single trapped and laser cooled radium ion we investigate atomic parity violation by probing the differential splitting (*light shifts*) of the 7S and 6D Zeeman levels, which is caused by the interaction of the ion with an off-resonant laser light field. This experiment serves as a low-energy test of the electroweak Standard Model of particle physics. With precision RF spectroscopy and subsequent monitoring of quantum jumps, this splitting can be determined to sub-Hertz accuracy. A proof-of-principle has recently been given for the barium ion, and crucial ideas are being extended to Ra{sup +} which is a superior candidate.

  3. Single and double charge transfer of He(2+) ions with molecules at near-thermal energies

    Science.gov (United States)

    Tosh, R. E.; Johnsen, R.

    1993-01-01

    Rate coefficients were measured for charge-transfer reactions of He(2+) ions with H2, N2, O2, CO, CO2, and H2O. The experiments were carried out using a selected-ion drift-tube mass spectrometer. Total rate coefficients are found to be very large and are generally close to the limiting Langevin capture rate coefficients or the corresponding ADO-model (Su and Bowers, 1973) coefficients. The product-ion spectra indicate that both single and double charge transfer and possibly transfer ionization occur in these reactions.

  4. On the crucial features of a single-file transport model for ion channels

    CERN Document Server

    Liang, Kuo Kan

    2013-01-01

    It has long been accepted that the multiple-ion single-file transport model is appropriate for many kinds of ion channels. However, most of the purely theoretical works in this field did not capture all of the important features of the realistic systems. Nowadays, large-scale atomic-level simulations are more feasible. Discrepancy between theories, simulations and experiments are getting obvious, enabling people to carefully examine the missing parts of the theoretical models and methods. In this work, it is attempted to find out the essential features that such kind of models should possess, in order that the physical properties of an ion channel be adequately reflected.

  5. In Situ Investigation of Li and Na Ion Transport with Single Nanowire Electrochemical Devices.

    Science.gov (United States)

    Xu, Xu; Yan, Mengyu; Tian, Xiaocong; Yang, Chuchu; Shi, Mengzhu; Wei, Qiulong; Xu, Lin; Mai, Liqiang

    2015-06-10

    In the past decades, Li ion batteries are widely considered to be the most promising rechargeable batteries for the rapid development of mobile devices and electric vehicles. There arouses great interest in Na ion batteries, especially in the field of static grid storage due to their much lower production cost compared with Li ion batteries. However, the fundamental mechanism of Li and Na ion transport in nanoscale electrodes of batteries has been rarely experimentally explored. This insight can guide the development and optimization of high-performance electrode materials. In this work, single nanowire devices with multicontacts are designed to obtain detailed information during the electrochemical reactions. This unique platform is employed to in situ investigate and compare the transport properties of Li and Na ions at a single nanowire level. To give different confinement for ions and electrons during the electrochemical processes, two different configurations of nanowire electrode are proposed; one is to fully immerse the nanowire in the electrolyte, and the other is by using photoresist to cover the nanowire with only one end exposed. For both configurations, the conductivity of nanowire decreases after intercalation/deintercalation for both Li and Na ions, indicating that they share the similar electrochemical reaction mechanisms in layered electrodes. However, the conductivity degradation and structure destruction for Na ions is more severe than those of Li ions during the electrochemical processes, which mainly results from the much larger volume of Na ions and greater energy barrier encountered by the limited layered spaces. Moreover, the battery performances of coin cells are compared to further confirm this conclusion. The present work provides a unique platform for in situ electrochemical and electrical probing, which will push the fundamental and practical research of nanowire electrode materials for energy storage applications.

  6. Directed evolution of antibody fragments with monovalent femtomolar antigen-binding affinity.

    Science.gov (United States)

    Boder, E T; Midelfort, K S; Wittrup, K D

    2000-09-26

    Single-chain antibody mutants have been evolved in vitro with antigen-binding equilibrium dissociation constant K(d) = 48 fM and slower dissociation kinetics (half-time > 5 days) than those for the streptavidin-biotin complex. These mutants possess the highest monovalent ligand-binding affinity yet reported for an engineered protein by over two orders of magnitude. Optimal kinetic screening of randomly mutagenized libraries of 10(5)-10(7) yeast surface-displayed antibodies enabled a >1,000-fold decrease in the rate of dissociation after four cycles of affinity mutagenesis and screening. The consensus mutations are generally nonconservative by comparison with naturally occurring mouse Fv sequences and with residues that do not contact the fluorescein antigen in the wild-type complex. The existence of these mutants demonstrates that the antibody Fv architecture is not intrinsically responsible for an antigen-binding affinity ceiling during in vivo affinity maturation.

  7. Feasibility of Observing and Characterizing Single Ion Strikes in Microelectronic Components.

    Energy Technology Data Exchange (ETDEWEB)

    Dingreville, Remi Philippe Michel [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hattar, Khalid Mikhiel [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Bufford, Daniel Charles [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    The transient degradation of semiconductor device performance under irradiation has long been an issue of concern. A single high energy charged particle can degrade or permanently destroy the microelectronic component potentially altering the course or function of the systems. Disruption of the the crystalline structure through the introduction of quasi-stable defect structures can change properties from semiconductor to conductor. Typically, the initial defect formation phase is followed by a recovery phase in which defect-defect or defect-dopant interactions modify the characteristics of the damaged structure. In this LDRD Express, in-situ ion irradiation transmission microscopy (TEM) in-situ TEM experiments combined with atomistic simulations have been conducted to determine the feasibility of imaging and characterizing the defect structure resulting from a single cascade in silicon. In-situ TEM experiments have been conducted to demonstrate that a single ion strike can be observed in Si thin films with nanometer resolution in real time using the in-situ ion irradiation transmission electron microscope (I 3 TEM). Parallel to this experimental effort, ion implantation has been numerically simulated using Molecular Dynamics (MD). This numerical framework provides detailed predictions of the damage and follow the evolution of the damage during the first nanoseconds. The experimental results demonstrate that single ion strike can be observed in prototypical semiconductors.

  8. Quantum Phase Transition in Quasi-two-dimensional Heisenberg Antiferromagnet with Single-Ion Anisotropy

    Institute of Scientific and Technical Information of China (English)

    JI An-Chun; TIAN Guang-Shan

    2007-01-01

    In the present paper, we investigate the quantum phase transition in a spatially anisotropic antiferromagnetic Heisenberg model of S = 1 with single-ion energy anisotropy. By using the Schwinger boson representation, we calculate the Gaussian correction to the critical value Jc⊥ caused by quantum spin fluctuations. We find that, for the positive single-ion energy, a nonzero value of Jc⊥ is always needed to stabilize the antiferromagnetic long-range order in this model. It resolves a difference among literature and shows clearly that the effect of quantum fluctuations may qualitatively change a result obtained by the mean-field theories on lower-dimensional systems.

  9. Critical properties of the transverse ferromagnetic spin system with random single-ion anisotropy

    Institute of Scientific and Technical Information of China (English)

    邓玲玲; 晏世雷

    2002-01-01

    A transverse ferromagnetic spin-1 system with a random single-ion anisotropy is considered in the framework of an Ising model. The effective field theory and decoupling approximation are applied to the derivation of the expressions of magnetizations for a honeycomb lattice. Special emphasis is placed on the critical properties of the system. New critical properties are obtained in a certain range of single-ion anisotropy, random concentration, and transverse field.We discuss in detail the influence of the random concentration and transverse field on the critical properties. Some phenomena have not been discovered in previous reports. Detailed descriptions of the phase transition and magnetization curves are presented.

  10. A comparison of batch and single wafer high dose arsenic ion implantation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, R.B.; Filo, A.J.; Kannan, V.C.; Feygenson, A.; Prematta, R.J.

    1989-04-01

    High dose, low energy (4x10/sup 15/ cm/sup -2/ at 15 keV) arsenic ion implantation into silicon was performed in batch and single wafer mode using medium and high current ion implanters. An investigation of implanted and annealed samples by Rutherford backscattering (RBS), transmission electron microscopy (TEM), thermal wave technique, and sheet resistance mapping showed little to no difference of arsenic profiles and residual damage between batch and single wafer implantation conditions when the sample temperature during implantation was kept below 120/sup 0/C. (orig.).

  11. A comparison of batch and single wafer high dose arsenic ion implantation techniques

    Science.gov (United States)

    Irwin, R. B.; Filo, A. J.; Kannan, V. C.; Feygenson, A.; Prematta, R. J.

    1989-04-01

    High dose, low energy (4×10 15 cm -2 at 15 keV) arsenic ion implantation into silicon was performed in batch and single wafer mode using medium and high current ion implanters. An investigation of implanted and annealed samples by Rutherford backscattering (RBS), transmission electron microscopy (TEM), thermal wave technique, and sheet resistance mapping showed little to no difference of arsenic profiles and residual damage between batch and single wafer implantation conditions when the sample temperature during implantation was kept below 120° C.

  12. Empirical laws of particle extraction from single-grid source of bipolar ion-electron flow

    Energy Technology Data Exchange (ETDEWEB)

    Dudin, S. V. [Department of Physics and Technology, V.N. Karazin Kharkiv National University, Kurchatova Ave. 31, 61108 Kharkiv (Ukraine); Scientific Center of Physical Technologies, Svobody sq. 6, 61022 Kharkiv (Ukraine); Rafalskyi, D. V. [Scientific Center of Physical Technologies, Svobody sq. 6, 61022 Kharkiv (Ukraine)

    2012-11-15

    The present research is devoted to the problem of extraction grid choice for a single-grid source of bipolar ion-electron flow. The paper contains detailed reference information on ion and electron extraction characteristics of 10 different grids with broad range of parameters: aperture width (0.09-0.6 mm), grid transparency (0.19-0.51), thickness (0.036-0.5 mm), and with different aperture geometry. The grids with square, circular, and slit apertures were made with different technologies: laser cutting, welding, weaving, and electrolytic erosion. The general regularities of the ion and electron extraction from the single-grid source are experimentally researched for the cases of dc and RF extraction grid biasing. A conclusion has been made that the maximum extracted ion current at low ion energy (0-200 eV) does not significantly vary for all the grids and does not exceed half of the primary ion current from plasma multiplied by the optical grid transparency. The low-energy limit of efficient ion extraction has been discovered which cannot be overcome by the aperture narrowing. A conclusion is made that the RF extraction mode is superior for all the researched grids since it is characterized by higher extracted ion current at any acceleration voltage for any grid with much more simple and smooth extraction curves behavior in comparison to the dc case as well as absence of arcing, jumps, and hysteresis of the measured curves at any RF voltages. The unique ability of the RF biased single-grid source of simultaneous ion/electron emission has been studied. The measured maximal attainable ion beam current compensation ratio is always sufficiently higher than 1 and typically varies in the range 2-6. The results obtained in the present paper demonstrate prospective of the single-grid source in space thruster applications and in modern technologies, particularly for ion beam processing of wide bandgap semiconductor devices such as GaN and SiC transistors due to inherent

  13. Development of real-time position detection system for single-ion hit

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, A., E-mail: yokoyama.akihito@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Kada, W. [Faculty of Science and Technology, Gunma University, 1-5-1 Tenjin-machi, Kiryu, Gunma 376-8515 (Japan); Satoh, T.; Koka, M.; Yamamoto, S.; Kamiya, T.; Yokota, W. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2014-08-01

    A real-time position detection system has been developed for a single-ion hit. The system is composed of a position sensitive camera unit and a luminescent scintillator. The camera unit includes 512 × 512 pixel electron-multiplier charge-coupled device, an image intensifier tube, and an object lens with a working distance of 101 mm. To obtain a highly sensitive luminescent scintillator for the detection of a single ion in the mega-electron-volt region, we investigate the photoluminescence properties of α-Al{sub 2}O{sub 3} single-crystals implanted with Eu(Al{sub 2}O{sub 3}:Eu) at a fluence ranging from 10{sup 14} to 10{sup 16} cm{sup −2}. The Al{sub 2}O{sub 3}:Eu samples were annealed at temperature from 500°C to 900°C. The results of 15-MeV O single-ion hit experiments using Al{sub 2}O{sub 3}:Eu with a fluence of 3.0 × 10{sup 16} cm{sup −2} annealed for 0.5 h at 600°C indicate that our system is sufficiently sensitive to detect the single-ion hit with a spatial resolution of 1 μm in real time.

  14. Single Ra{sup +} ion spectroscopy - towards a measurement of atomic parity violation

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Portela, Mayerlin; Mohanti, A.; Dijck, E.A.; Bekker, H.; Boell, O.; Berg, J. van den; Giri, G.S.; Jungmann, K.; Onderwater, C.J.G.; Santra, B.; Timmermans, R.G.E.; Versolato, O.O.; Wansbeek, L.W.; Willmann, L.; Wilschut, H.W. [KVI, University of Groningen, Groningen (Netherlands)

    2013-07-01

    The sensitivity of the Atomic Parity Violation (APV) signal grows faster than the third power of the atomic number Z. Ra{sup +} (Z=88) is heaviest alkaline earth ion available. A single trapped Ra{sup +} ion opens a very promising path for a measurement atomic parity violation. One of the experimental challenges is the localization of the ion within a fraction of an optical wavelength. For this the current experiments are focused on trapping and laser cooling of Ba{sup +} ions as a precursor for Ra{sup +}. Ba{sup +} ions are trapped and laser cooled in a precision hyperbolic Paul trap. Work towards single Ba{sup +} ion localization and detection is in progress. Recently the hyperfine structure of the 6d{sub 2}D{sub 3/2} states and the isotope shift of the 6d{sub 2}D{sub 3/2}-7p{sub 2}P{sub 1/2} transition in the isotopes {sup 209-214}Ra{sup +} has been measured in online laser spectroscopy experiments at the KVI AGOR/TRIμP facility. These results are essential for the interpretation of an APV measurement in Ra{sup +}.

  15. Magnetic anisotropy of a Co-II single ion magnet with distorted trigonal prismatic coordination

    DEFF Research Database (Denmark)

    Peng, Yan; Bodenstein, Tilmann; Fink, Karin

    2016-01-01

    The single ion magnetic properties of Co(II) are affected by the details of the coordination geometry of the ion. Here we show that a geometry close to trigonal prismatic which arises when the ligand 6,6'-((1Z)-((piperazine-1,4-diylbis(propane-3,1-diyl)) bis(azanylylidene)) bis(methanylylidene)) ......The single ion magnetic properties of Co(II) are affected by the details of the coordination geometry of the ion. Here we show that a geometry close to trigonal prismatic which arises when the ligand 6,6'-((1Z)-((piperazine-1,4-diylbis(propane-3,1-diyl)) bis(azanylylidene)) bis......(methanylylidene)) bis(2-methoxyphenol) coordinates to Co(II) does indeed lead to enhanced single-ion behaviour as has previously been predicted. Synthesis of the compound, structural information, and static as well as dynamic magnetic data are presented along with an analysis using quantum chemical ab initio...

  16. Ion beam induced single phase nanocrystalline TiO{sub 2} formation

    Energy Technology Data Exchange (ETDEWEB)

    Rukade, Deepti A. [Department of Physics, University of Mumbai, Mumbai 400098 (India); Tribedi, L.C. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Bhattacharyya, Varsha, E-mail: varsha.b1.physics@gmail.com [Department of Physics, University of Mumbai, Mumbai 400098 (India)

    2014-06-15

    Single phase TiO{sub 2} nanostructures are fabricated by oxygen ion implantation (60 keV) at fluence ranging from 1×10{sup 16} ions/cm{sup 2} to 1×10{sup 17} ions/cm{sup 2} in titanium thin films deposited on fused silica substrate and subsequent thermal annealing in argon atmosphere. GAXRD and Raman spectroscopy study reveals formation of single rutile phases of TiO{sub 2}. Particle size is found to vary from 29 nm to 35 nm, establishing nanostructure formation. Nanostructure formation is also confirmed by the quantum confinement effect manifested by the blueshift of the UV–vis absorption spectra. Photoluminescence spectra show peaks corresponding to TiO{sub 2} rutile phase and reveal the presence of oxygen defects due to implantation. The controlled synthesis of single phase nanostructure is attributed to ion induced defects and post-implantation annealing. It is observed that the size of the nanostructures formed is strongly dependent on the ion fluence.

  17. Towards a precise measurement of atomic parity violation in a single Ra{sup +} ion

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Portela, M., E-mail: nunez@kvi.nl; Berg, J. E. van den; Bekker, H.; Boell, O.; Dijck, E. A.; Giri, G. S.; Hoekstra, S.; Jungmann, K.; Mohanty, A.; Onderwater, C. J. G.; Santra, B.; Schlesser, S.; Timmermans, R. G. E.; Versolato, O. O.; Wansbeek, L. W.; Willmann, L.; Wilschut, H. W. [Kernfysisch Versneller Instituut (KVI) (Netherlands)

    2013-03-15

    A single trapped Ra{sup + } (Z = 88) ion provides a very promising route towards a most precise measurement of Atomic Parity Violation (APV), since APV effects grow faster than Z{sup 3}. This experiment promises the best determination of the electroweak coupling constant at the lowest accessible energies. Such a measurement provides a sensitive test of the Standard Model in particle physics. At the present stage of the experiment, we focus on trapping and laser cooling stable Ba{sup + } ions as a precursor for radioactive Ra{sup + }. Online laser spectroscopy of the isotopes {sup 209 - 214}Ra{sup + } in a linear Paul trap has provided information on transition wavelengths, fine and hyperfine structures and excited state lifetimes as test of atomic structure calculations. Additionaly, a single trapped Ra{sup + } ion could function as a very stable clock.

  18. Development of noise-suppressed detector for single ion hit system

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Takuro; Hamano, Tsuyoshi; Suda, Tamotsu; Hirao, Toshio; Kamiya, Tomihiro [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    A noise-suppressed detector for single ion detection has been developed, and combined with the heavy ion microbeam apparatus. This detector consists of a pair of micro channel plates (MCP`s) and a very thin carbon foil. The detection signal is formed by the coincidence of the signals from these MCP`s, so that this detector and the coincidence measurement unit can reduce miscounting in the circuit. The detection efficiency for 15 MeV heavy ions was evaluated to be comparable to that of a silicon surface-barrier detector (SSD) and the miscounting rate was 4 orders lower than the noise rate of a single MCP. The rise time of the detection signal was also estimated. (author)

  19. Kinetics of a single trapped ion in an ultracold buffer gas

    CERN Document Server

    Zipkes, Christoph; Sias, Carlo; Köhl, Michael

    2010-01-01

    The immersion of a single ion confined by a radiofrequency trap in an ultracold atomic gas extends the concept of buffer gas cooling to a new temperature regime. The steady state energy distribution of the ion is determined by its kinetics in the radiofrequency field rather than the temperature of the buffer gas. Moreover, the finite size of the ultracold gas facilitates the observation of back-action of the ion onto the buffer gas. We numerically investigate the system's properties depending on mass ratio, trap geometry, differential cross-section, and non-uniform neutral atom density distribution. We identify excess micromotion to set the typical scale for the ion energy statistics and explore the applicability of the mobility collision cross-section to the ultracold regime.

  20. Fragmentation of phosphorylated and singly charged peptide ions via interaction with metastable atoms.

    Science.gov (United States)

    Berkout, Vadym D; Doroshenko, Vladimir M

    2008-12-01

    Fragmentation of phosphorylated peptide ions via interaction with electronically excited metastable argon atoms was studied in a linear trap - time-of-flight mass spectrometer. Doubly charged ions of phosphorylated peptides from an Enolase digest were produced by electrospray ionization and subjected to a metastable atom beam in the linear trap. The metastable argon atoms were generated using a glow-discharge source. An intensive series of c- and z- ions were observed in all cases, with the phosphorylation group intact. The formation of molecular radical cations with reduced charge indicated that an electron transfer from a highly excited metastable state of argon to the peptide cation occurred. Additionally, singly charged Bradykinin, Substance P and Fibrinopeptide A molecular ions were fragmented via interaction with electronically excited metastable helium atoms. The fragmentation mechanism was different in this case and involved Penning ionization.

  1. Two mode coupling in a single ion oscillator via parametric resonance

    CERN Document Server

    Gorman, Dylan J; Selvarajan, Sankaranarayanan; Daniilidis, Nikos; Häffner, Hartmut

    2014-01-01

    Atomic ions, confined in radio-frequency Paul ion traps, are a promising candidate to host a future quantum information processor. In this letter, we demonstrate a method to couple two motional modes of a single trapped ion, where the coupling mechanism is based on applying electric fields rather than coupling the ion's motion to a light field. This reduces the design constraints on the experimental apparatus considerably. As an application of this mechanism, we cool a motional mode close to its ground state without accessing it optically. As a next step, we apply this technique to measure the mode's heating rate, a crucial parameter determining the trap quality. In principle, this method can be used to realize a two-mode quantum parametric amplifier.

  2. Modifying the properties of 4f single-ion magnets by peripheral ligand functionalisation

    DEFF Research Database (Denmark)

    Pedersen, Kasper Steen; Ungur, Liviu; Sigrist, Marc;

    2014-01-01

    We study the ligand-field splittings and magnetic properties of three ErIII single-ion magnets which differ in the peripheral ligand sphere but exhibit similar first coordination spheres by inelastic neutron scattering (INS) and SQUID magnetometry. The INS spectra of the three compounds are profo...

  3. An organometallic sandwich lanthanide single-ion magnet with an unusual multiple relaxation mechanism.

    Science.gov (United States)

    Jeletic, Matthew; Lin, Po-Heng; Le Roy, Jennifer J; Korobkov, Ilia; Gorelsky, Serge I; Murugesu, Muralee

    2011-12-07

    A dysprosium(III) sandwich complex, [Dy(III)(COT″)(2)Li(THF)(DME)], was synthesized using 1,4-bis(trimethylsilyl)cyclooctatetraenyl dianion (COT″). The complex behaves as a single-ion magnet and demonstrates unusual multiple relaxation modes. The observed relaxation pathways strongly depend on the applied static dc fields.

  4. The magnetic properties of the spin-1 Heisenberg antiferromagnetic chain with single-ion anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Gangsan; Zhu, Rengui, E-mail: rgzhu@mail.ahnu.edu.cn

    2015-02-15

    The magnetic properties of the spin-1 Heisenberg antiferromagnetic chain with exchange anisotropy and single-ion anisotropy are studied by the double-time Green's function method. The determinative equations for the critical temperature, the magnetization, and the zero-field susceptibility are derived analytically. The effects of the anisotropies on the magnetic properties are presented.

  5. Towards a Precise Measurement of Atomic Parity Violation in a Single Ra+ Ion

    NARCIS (Netherlands)

    Jungmann, K.; Giri, G. S.; Versolato, O. O.; Steadman, SG; Stephans, GSF; Taylor, FE

    2012-01-01

    In the singly charged Ra+ ion the contributions of the weak interactions to the atomic level energies are some 50 times larger than in the Cs atom. We report the results of laser spectroscopy experiments on Ra-209-214(+) isotopes in preparation of a precision atomic parity violation experiment. Expe

  6. Towards a precise measurement of atomic parity violation in a single Ra+ ion

    NARCIS (Netherlands)

    Nunez Portela, M.; van den Berg, J. E.; Bekker, H.; Giri, G.S.; Hoekstra, S.; Jungmann, K.; Mohanty, A.; Onderwater, G.J.C.; Santra, B.; Schlesser, S.; Timmermans, R.G.E.; Versolato, O.O.; Wansbeek, L.W.; Willmann, L.; Wilschut, H.W.

    2013-01-01

    A single trapped Ra+(Z= 88) ion provides a very promising route towards a most precise measurement of Atomic Parity Violation (APV), since APV effects grow faster than Z 3. This experiment promises the best determination of the electroweak coupling constant at the lowest accessible energies. Such a

  7. Potential of electric quadrupole transitions in radium isotopes for single-ion optical frequency standards

    NARCIS (Netherlands)

    Versolato, O. O.; Wansbeek, L. W.; Jungmann, K.; Timmermans, R. G. E.; Willmann, L.; Wilschut, H. W.

    2011-01-01

    We explore the potential of the electric quadrupole transitions 7s (2)S(1/2)-(6)d (2)D(3/2), 6d (2)D(5/2) in radium isotopes as single-ion optical frequency standards. The frequency shifts of the clock transitions due to external fields and the corresponding uncertainties are calculated. Several

  8. Single stage ECR source for the radioactive ion beam project in Louvain- la-Neuve

    Energy Technology Data Exchange (ETDEWEB)

    Arnould, M.; Vanhorenbeeck, J.; Baeten, F.; Dom, C.; Darquennes, D.; Delbar, T.; Jongen, Y.; Huyse, M.; Reusen, G.; Van Duppen, P. and others

    1989-01-01

    In 1987 the project RIB (Radioactive Ion Beam) was started at Louvain-La - Neuve, to produce and accelerate radioactive nuclei of C, N, O, F and Ne. Within the framework of this project, a single stage E.C.R. source will be built. The general scheme of the project and the design of the source are discussed.

  9. Scattering of slow ions by various crystallographic planes of tungsten single crystals

    CERN Document Server

    Ermolov, S N; Kortenraad, R; Must, B; Shtinov, E D; Brongersma, K K

    2002-01-01

    The dependence of low-energy ion scattering signal intensity on single crystal surface orientation is investigated, and it is shown that this dependence is not necessarily in direct proportion to atomic density in the uppermost atomic layer. On the basis of comparison of signals from various crystallographic planes of a high purity W single crystal a conclusion is made that the ions scattered from more deep atomic layers contribute considerably to the signal measured for the surface with an open structure. It is shown that reference specimens with a known surface density are needed for quantitative analysis of surface composition by the method of low-energy ion scattering. The best reference specimens are well-oriented single crystals with close-packed planes at the surface, since in this case the low-energy ion scattering signal is proportional to atomic density of the uppermost atomic layer. It single crystals with open surface structure are used as reference specimens the contribution of deeper atomic laye...

  10. Focused ion beam milling of nanocavities in single colloidal particles and self-assembled opals

    NARCIS (Netherlands)

    Woldering, Leon A.; Otter, A.M.(Bert); Husken, Bart H.; Vos, Willem L.

    2006-01-01

    We present a new method of realizing single nanocavities in individual colloidal particles on the surface of silicon dioxide artificial opals using a focused ion beam milling technique. We show that both the radius and the position of the nanocavity can be controlled with nanometre precision, to rad

  11. Production of multi-, oligo- and single-pore membranes using a continuous ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Apel, P.Yu., E-mail: apel@nrmail.jinr.ru [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna (Russian Federation); Dubna International University, Universitetskaya Str. 19, 141980 Dubna (Russian Federation); Ivanov, O.M.; Lizunov, N.E.; Mamonova, T.I.; Nechaev, A.N. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna (Russian Federation); Olejniczak, K. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna (Russian Federation); Faculty of Chemistry, Nicolaus Copernicus University, Gagarina Str. 7, 87-100 Torun (Poland); Vacik, J. [Nuclear Physics Institute, ASCR, v.v.i., 25068 Řež (Czech Republic); Dmitriev, S.N. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna (Russian Federation)

    2015-12-15

    Ion track membranes (ITM) have attracted significant interest over the past two decades due to their numerous applications in physical, biological, chemical, biochemical and medical experimental works. A particular feature of ITM technology is the possibility to fabricate samples with a predetermined number of pores, including single-pore membranes. The present report describes a procedure that allowed for the production of multi-, oligo- and single-pore membranes using a continuous ion beam from an IC-100 cyclotron. The beam was scanned over a set of small diaphragms, from 17 to ∼1000 μm in diameter. Ions passed through the apertures and impinged two sandwiched polymer foils, with the total thickness close to the ion range in the polymer. The foils were pulled across the ion beam at a constant speed. The ratio between the transport speed and the scanning frequency determined the distance between irradiation spots. The beam intensity and the aperture diameters were adjusted such that either several, one or no ions passed through the diaphragms during one half-period of scanning. After irradiation, the lower foil was separated from the upper foil and was etched to obtain pores 6–8 μm in diameter. The pores were found using a color chemical reaction between two reagents placed on opposite sides of the foil. The located pores were further confirmed using SEM and optical microscopy. The numbers of tracks in the irradiation spots were consistent with the Poisson statistics. Samples with single or few tracks obtained in this way were employed to study fine phenomena in ion track nanopores.

  12. Dynamics of a single trapped ion immersed in a buffer gas

    CERN Document Server

    Höltkemeier, Bastian; López-Carrera, Henry; Weidemüller, Matthias

    2016-01-01

    We provide a comprehensive theoretical framework for describing the dynamics of a single trapped ion interacting with a neutral buffer gas, thus extending our previous studies on buffer-gas cooling of ions beyond the critical mass ratio [B. H\\"oltkemeier et al., Phys. Rev. Lett. 116, 233003 (2016)]. By transforming the collisional processes into a frame, where the ion's micromotion is assigned to the buffer gas atoms, our model allows one to investigate the influence of non-homogeneous buffer gas configurations as well as higher multipole orders of the radio-frequency trap in great detail. Depending on the neutral-to-ion mass ratio, three regimes of sympathetic cooling are identified which are characterized by the form of the ion's energy distribution in equilibrium. We provide analytic expressions and numerical simulations of the ion's energy distribution, spatial profile and cooling rates for these different regimes. Based on these findings, a method for actively decreasing the ion's energy by reducing the ...

  13. Diode-like properties of single- and multi-pore asymmetric track membranes

    Energy Technology Data Exchange (ETDEWEB)

    Zielinska, K., E-mail: kziel@jinr.ru [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna (Russian Federation); Faculty of Chemistry, Nicolaus Copernicus University, Gagarina str. 7, 87-100 Torun (Poland); Gapeeva, A.R.; Orelovich, O.L. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna (Russian Federation); Apel, P.Yu. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna (Russian Federation); The International University “Dubna”, Universitetskaya str. 19, 141980 Dubna (Russian Federation)

    2014-05-01

    In this work, we investigated the ionic transport properties of asymmetric polyethylene terephthalate (PET) track membranes with the thickness of 5 μm. The samples containing single pores and arrays of many pores were fabricated by irradiation with accelerated ions and subsequent physicochemical treatment. The method of etching in the presence of a surface-active agent was used to prepare the pores with highly-tapered tip. The transport of monovalent inorganic ions through the nano-scale holes was studied in a conductivity cell. The effective pore radii, electrical conductance and rectification ratios of pores were measured. The geometric characteristics of nanopores were investigated using FESEM.

  14. Ferrimagnetic Properties of Bond Dilution Mixed Blume-Capel Model with Random Single-Ion Anisotropy

    Institute of Scientific and Technical Information of China (English)

    LIU Lei; YAN Shi-Lei

    2005-01-01

    We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory.The system is considered in the framework of bond dilution mixed Blume-Capel model (BCM) with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points.Normal magnetic ordering states take on new phase diagrams with increasing randomness (bond and anisotropy), while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random single-ion anisotropy.Some results have not been revealed in Previous papers and predicted by Néel theory of ferrimagnetism.

  15. Scalable Focused Ion Beam Creation of Nearly Lifetime-Limited Single Quantum Emitters in Diamond Nanostructures

    CERN Document Server

    Schröder, Tim; Walsh, Michael; Li, Luozhou; Zheng, Jiabao; Schukraft, Marco; Pacheco, Jose L; Camacho, Ryan M; Bielejec, Edward S; Sipahigil, Alp; Evans, Ruffin E; Sukachev, Denis D; Nguyen, Christian T; Lukin, Mikhail D; Englund, Dirk

    2016-01-01

    The controlled creation of defect center---nanocavity systems is one of the outstanding challenges for efficiently interfacing spin quantum memories with photons for photon-based entanglement operations in a quantum network. Here, we demonstrate direct, maskless creation of atom-like single silicon-vacancy (SiV) centers in diamond nanostructures via focused ion beam implantation with $\\sim 32$ nm lateral precision and $< 50$ nm positioning accuracy relative to a nanocavity. Moreover, we determine the Si+ ion to SiV center conversion yield to $\\sim 2.5\\%$ and observe a 10-fold conversion yield increase by additional electron irradiation. We extract inhomogeneously broadened ensemble emission linewidths of $\\sim 51$ GHz, and close to lifetime-limited single-emitter transition linewidths down to $126 \\pm13$ MHz corresponding to $\\sim 1.4$-times the natural linewidth. This demonstration of deterministic creation of optically coherent solid-state single quantum systems is an important step towards development o...

  16. A single particle detector for electron-ion collision experiments in the Cryogenic Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Spruck, Kaija; Mueller, Alfred; Schippers, Stefan [Institut fuer Atom- und Molekuelphysik, Justus-Liebig-Universitaet Giessen (Germany); Krantz, Claude; Becker, Arno; Vogel, Stephen; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Novotny, Oldrich [Columbia Astrophysics Laboratory, New York (United States)

    2014-07-01

    The study of ion chemistry in the interstellar medium requires, among others, knowledge about cross sections for the recombination of atomic and molecular ions with low temperature (∝10 K) electrons. Especially the database on singly charged atomic ions relevant to the chemistry of molecular clouds is incomplete in this respect. The electrostatic Cryogenic Storage Ring (CSR), currently being commissioned at the Max-Planck-Institute for Nuclear Physics in Heidelberg, will allow experiments with atomic, molecular and cluster ions at beam energies up to 300 keV per unit charge in a cryogenic extremely high vacuum (XHV) environment. Collisions of stored atomic ions with electrons provided by an electron cooler will lead to reaction products with charge states that differ from those of the parent particles. The detection of these products will be carried out behind a bending deflector of the storage ring by a high-efficiency movable single-particle detector, based on a secondary electron converter backed by heatable microchannel plates. The designs of the mechanical actuator and the detector are compatible with the cryogenic operating conditions at 10 K and a bakeout temperature of up to 530 K.

  17. Polygonisation of ionic single crystals - a new effect of swift ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Turos, A.; Nowicki, L. [The Andrzej Soltan Institute for Nuclear Studies, Warsaw (Poland); Garrido, F.; Thome, L. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay (France); Fromknecht, R. [Research Center Karlsruhe, INFP, Karlsruhe (Germany); Domagala, J. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland)

    1999-05-01

    Isostructural oxide single crystals of the fluorite structure: stabilized cubic zirconia and UO{sub 2} were bombarded at room temperature with 72 MeV iodine ions or 340 MeV Xe ions, respectively. The aim of this paper was the study of structural transformations induced by ion bombardment in two different regimes: at 72 MeV where the radiation damage production is strongly influenced by collision cascades and at higher energies where the ionization mechanism prevails. The structure of as-grown and implanted single crystals was examined using the RBS/channeling technique and X-ray diffraction analysis. Some of the samples were also investigated by transmission electron microscopy. It was observed that the residual damage depends strongly on energy loss mechanism, and hence on the incident ion energy. At high incident energies solidification of latent tracks in UO{sub 2} leads to their polygonisation. Since the energy of 72 MeV is too low for latent track formation, the resulting damage is composed of dislocation and clusters and is similar to that created by the ion bombardment at low energies. The amount of defects was strongly enhanced by the interaction of ionised regions with collision cascades. (author) 14 refs, 4 figs

  18. Ionoluminescence analysis of glass scintillators and application to single-ion-hit real-time detection

    Science.gov (United States)

    Yokoyama, Akihito; Kada, Wataru; Satoh, Takahiro; Koka, Masashi; Shimada, Keisuke; Yokoata, Yuya; Miura, Kenta; Hanaizumi, Osamu

    2016-03-01

    In this paper, we propose and test a real-time detection system for single-ion hits using mega-electronvolt (MeV)-heavy ions. The system was constructed using G2000 and G9 glass scintillators, as well as an electron-multiplying charge-coupled device (EMCCD) camera combined with an inverted microscope with a 10× objective lens. Commercially available G2000 and G9 glass scintillators, which have been reported to exhibit strong photoluminescence at 489, 543, 585, and 622 nm as a result of the Tb3+ f-f transition, were employed for highly accurate ionized particle detection. The EMCCD camera had a resolution of 512 × 512 pixels, each with a size of 16 μm × 16 μm, and a maximum linear gain of 8 × 105 electrons. For 260-MeV Ne, 3 ion hits/s were detected by our system. The intensity of the ionoluminescence (IL) peak induced by the heavy ions was 140 times the noise intensity. In contrast, the luminous diameter at the full width at half maximum (FWHM) in both the horizontal and vertical directions was calculated to be approximately 4.5 μm. These results suggest that our detection system can accurately detect single-ion hits with a diameter of the order of 1 μm.

  19. Creation of nanohillocks on CaF2 surfaces by single slow highly charged ions.

    Science.gov (United States)

    El-Said, A S; Heller, R; Meissl, W; Ritter, R; Facsko, S; Lemell, C; Solleder, B; Gebeshuber, I C; Betz, G; Toulemonde, M; Möller, W; Burgdörfer, J; Aumayr, F

    2008-06-13

    Upon impact on a solid surface, the potential energy stored in slow highly charged ions is primarily deposited into the electronic system of the target. By decelerating the projectile ions to kinetic energies as low as 150 x q eV, we find first unambiguous experimental evidence that potential energy alone is sufficient to cause permanent nanosized hillocks on the (111) surface of a CaF(2) single crystal. Our investigations reveal a surprisingly sharp and well-defined threshold of potential energy for hillock formation which can be linked to a solid-liquid phase transition.

  20. Absolute single photoionization cross-section measurements of Rb 2+ ions: experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Macaluso, D. A. [Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy; Bogolub, K. [Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy; Johnson, A. [Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy; Aguilar, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Kilcoyne, A. L. D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Bilodeau, R. C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Univ. of Connecticut, Storrs, CT (United States). Dept. of Physics; Bautista, M. [Western Michigan Univ., Kalamazoo MI (United States). Dept. of Physics; Kerlin, A. B. [Univ. of West Georgia, Carrolton, GA (United States). Dept. of Physics; Sterling, N. C. [Univ. of West Georgia, Carrolton, GA (United States). Dept. of Physics

    2017-05-05

    Absolute single photoionization cross-section measurements of Rb 2+ ions were performed at the Advanced Light Source at Lawrence Berkeley National Laboratory using synchrotron radiation and the photo-ion, merged-beams technique. Measurements were made at a photon energy resolution of 13.5 2.5 meV from 37.31 to 44.08 eV spanning the 2 P ground state and 2 P metastable state ionization thresholds. Multiple autoionizing resonance series arising from each initial state are identified using quantum defect theory. The measurements are compared to Breit-Pauli R-matrix calculations with excellent agreement between theory and experiment.

  1. Generation of Schr(o)dinger cat state of a single trapped cold ion

    Institute of Scientific and Technical Information of China (English)

    Zhang Miao; Jia Huan-Yu; Ji Xiao-Hui; Si Kun

    2009-01-01

    The fidelity of the generated Schr(o)dinger Cat state (SCS) of a single trapped ion in the Lamb-Dicke approximation is discussed. The results show that the fidelity significantly decreases with the values of Lamb-Dicke parameter η and coherent state amplitude α increasing. For η = 0.20 and α = 3, the typical values of experimental parameters, the fidelity is rather low (30%). A scheme for generating the SCS is proposed without making the Lamb-Dike approximation in laser-ion interaction, and the fidelity of the generated SCS is about 99% for the typical values of experimental Lamb-Dicke parameters.

  2. Poisson-Fermi model of single ion activities in aqueous solutions

    Science.gov (United States)

    Liu, Jinn-Liang; Eisenberg, Bob

    2015-09-01

    A Poisson-Fermi model is proposed for calculating activity coefficients of single ions in strong electrolyte solutions based on the experimental Born radii and hydration shells of ions in aqueous solutions. The steric effect of water molecules and interstitial voids in the first and second hydration shells play an important role in our model. The screening and polarization effects of water are also included in the model that can thus describe spatial variations of dielectric permittivity, water density, void volume, and ionic concentration. The activity coefficients obtained by the Poisson-Fermi model with only one adjustable parameter are shown to agree with experimental data, which vary nonmonotonically with salt concentrations.

  3. Single-ion anisotropy in the gadolinium pyrochlores studied by electron paramagnetic resonance

    Science.gov (United States)

    Glazkov, V. N.; Zhitomirsky, M. E.; Smirnov, A. I.; Krug von Nidda, H.-A.; Loidl, A.; Marin, C.; Sanchez, J.-P.

    2005-07-01

    The electron paramagnetic resonance is used to measure the single-ion anisotropy of Gd3+ ions in the pyrochlore structure of (Y1-xGdx)2Ti2O7 . A rather strong easy-plane-type anisotropy is found. The anisotropy constant D is comparable to the exchange integral J in the prototype Gd2Ti2O7 , D≃0.75J , and exceeds the dipolar energy scale. Physical implications of an easy-plane anisotropy for a pyrochlore antiferromagnet are considered. We calculate the magnetization curves at T=0 and discuss phase transitions in a magnetic field.

  4. Quantum Decoherence of a Single Trapped Ion due to Engineered Reservoir

    Institute of Scientific and Technical Information of China (English)

    YI Xue-Xi

    2002-01-01

    Known as an engineered reservoir due to fluctuations in trap parameter,a classical source of quantum decoherence is considered for a single trapped ion theoretically.For simplicity it is assumed that the fluctuations involved are white noise processes,which enables us to give a simple master equation description of this source of decoherence.Our results show that the decoherence rate depends on the vibrational quantum number in different ways corresponding to the vibrational excitation sideband used there.Besides,this source of decoherence also leads to occurrence of dissipation in the ion system.

  5. UV-sensitive superconducting nanowire single photon detectors for integration in an ion trap

    CERN Document Server

    Slichter, D H; Leibfried, D; Mirin, R P; Nam, S W; Wineland, D J

    2016-01-01

    We demonstrate superconducting nanowire single photon detectors with 76 +/- 4 % system detection efficiency at a wavelength of 315 nm and an operating temperature of 3.2 K, with a background count rate below 1 count per second at saturated detection efficiency. We propose integrating these detectors into planar surface electrode radio-frequency Paul traps for use in trapped ion quantum information processing. We operate detectors integrated into test ion trap structures at 3.8 K both with and without typical radio-frequency trapping electric fields. The trapping fields reduce system detection efficiency by 9 %, but do not increase background count rates.

  6. Experimental studies of single-event effects induced by heavy ions

    Science.gov (United States)

    Liu, J.; Hou, M. D.; Li, B. Q.; Liu, C. L.; Wang, Z. G.; Cheng, S.; Sun, Y. M.; Jin, Y. F.; Lin, Y. L.; Cai, J. R.; Wang, S. J.; Ye, Z. H.; Zhu, G. W.; Du, H.; Ren, Q. Y.; Wu, W.; Mao, X. M.; Sun, Y. Q.; Guo, R.

    2000-04-01

    This paper presents the results of ground-based heavy ion test of single-event effect (SEE) vulnerability on microcircuits used in space. We observed the dependence of upset cross-sections on the incident angle of ions in Intel 8086 CPU. SEU cross-sections of various SRAMs did not depend on the stored pattern, but 0→1 and 1→0 transitions were completely different for different manufacturer products. Some SEE protection methods were verified in conditions of ground simulation experiments.

  7. Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

    Institute of Scientific and Technical Information of China (English)

    Wang Fei; Gou Bing-Cong

    2008-01-01

    This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar16+ ions with He atoms in the velocity range of 1.2-1.9 a.u.. The relative importance of single ionization (SI) to single capture (SC) is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u..

  8. Nanowires: Quantitative Probing of Cu(2+) Ions Naturally Present in Single Living Cells (Adv. Mater. 21/2016).

    Science.gov (United States)

    Lee, Junho; Lee, Hwa-Rim; Pyo, Jaeyeon; Jung, Youngseob; Seo, Ji-Young; Ryu, Hye Guk; Kim, Kyong-Tai; Je, Jung Ho

    2016-06-01

    Quantitative probing of the Cu(2+) ions naturally present in single living cells is accomplished by a probe made from a quantum-dot-embedded-nanowire waveguide. After inserting the active nanowire-based waveguide probe into single living cells, J. H. Je and co-workers directly observe photoluminescence (PL) quenching of the embedded quantum dots by the Cu(2+) ions diffused into the probe as described on page 4071. This results in quantitative measurement of intracellular Cu(2+) ions.

  9. New strategy to construct single-ion magnets: a unique Dy@Zn₆ cluster exhibiting slow magnetic relaxation.

    Science.gov (United States)

    Xiong, Gang; Qin, Xiang-Yang; Shi, Peng-Fei; Hou, Yin-Ling; Cui, Jian-Zhong; Zhao, Bin

    2014-04-25

    Two unique heptanuclear clusters Ln@Zn6 (Ln = Dy (1), Er (2)) were structurally and magnetically characterized. Each Dy(3+)/Er(3+) is located in a nona-coordinate D(3h) coordination environment, and is encapsulated in a diamagnetic Zn6 cage. Compound 1 exhibits single-ion magnetic behavior, and is the first example of a single-ion magnet (SIM) constructed through embedding one magnetic anisotropic metal ion into a diamagnetic cage.

  10. High-resolution fast ion microscopy of single whole biological cells

    Science.gov (United States)

    Bettiol, Andrew A.; Mi, Zhaohong; Watt, Frank

    2016-12-01

    High-resolution microscopy techniques have become an essential tool in both biological and biomedical sciences, enabling the visualization of biological processes at cellular and subcellular levels. For many years, these imaging techniques utilized conventional optical microscopes including those with confocal facilities. However, the spatial resolutions achieved were largely limited to around 200 nm, as determined by the diffraction of light. To overcome this diffraction barrier, considerable scientific and technological effort has resulted in the development of super-resolution optical-based techniques, scanning probe microscopies, and also techniques utilizing charged particles (e.g., energetic electrons and ions) or high-energy photons (e.g., X-ray), which exhibit much shorter de Broglie wavelengths. Among the charged particle techniques, those utilizing mega-electron-volt (MeV) ion beams appear to have unique advantages primarily because MeV ions can penetrate through several microns of biological tissue (e.g., whole cells) with little deflection in their trajectories, and hence spatial resolutions are maintained while traversing the sample. Recently, we have witnessed the significant development of MeV ion beam focusing systems in reducing beam dimensions well below 100 nm, such that single whole cell imaging at 20 nm spatial resolutions is now possible. In this review, two super resolution imaging modalities that utilize MeV highly focused ion beams are discussed: Scanning Transmission Ion Microscopy (STIM), which images the areal density of cells and gives an insight into the cellular structure, and Proton/Helium-ion Induced Fluorescence Microcopy (P/HeIFM), which images the fluorescence emission of fluorescent markers and probes used as labels within the cells. This review hopes to demonstrate the potential of MeV ion microscopy, which is still in its infancy, and describe the simultaneous use of STIM and P/HeIFM as a new and powerful multifaceted

  11. Investigating change of properties in gallium ion irradiation patterned single-layer graphene

    Science.gov (United States)

    Wang, Quan; Dong, Jinyao; Bai, Bing; Xie, Guoxin

    2016-10-01

    Besides its excellent physical properties, graphene promises to play a significant role in electronics with superior properties, which requires patterning of graphene for device integration. Here, we presented the changes in properties of single-layer graphene before and after patterning using gallium ion beam. Combined with Raman spectra of graphene, the scanning capacitance microscopy (SCM) image confirmed that a metal-insulator transition occurred after large doses of gallium ion irradiation. The changes in work function and Raman spectra of graphene indicated that the defect density increased as increasing the dose and a structural transition occurred during gallium ion irradiation. The patterning width of graphene presented an increasing trend due to the scattering influence of the impurities and the substrate.

  12. Discussion of the metric in characterizing the single-event effect induced by heavy ions

    Institute of Scientific and Technical Information of China (English)

    Zhang Ke-Ying; Zhang Feng-Qi; Luo Yin-Hong; Guo Hong-Xia

    2013-01-01

    The single-event effect (SEE) is the most serious problem in space environment.The modern semiconductor technology is concerned with the feasibility of the linear energy transfer (LET) as metric in characterizing SEE induced by heavy ions.In this paper,we calibrate the detailed static random access memory (SRAM) cell structure model of an advanced field programmable gate array (FPGA) device using the computer-aided design tool,and calculate the heavy ion energy loss in multi-layer metal utilizing Geant4.Based on the heavy ion accelerator experiment and numerical simulation,it is proved that the metric of LET at the device surface,ignoring the top metal material in the advanced semiconductor device,would underestimate the SEE.In the SEE evaluation in space radiation environment the top-layers on the semiconductor device must be taken into consideration.

  13. Design of the CAS-LIBB Single-Ion Microbeam Endstation Ⅱ

    Institute of Scientific and Technical Information of China (English)

    XU Yongjian; HU Zhiwen; CHEN Lianyun; XU Mingliang; ZHAN Furu; YU Zengliang

    2008-01-01

    Cellular micro-irradiation is now recognized as a powerful technique to unveil the mechanisms of interaction between ionizing radiation and living cells or tissues. The single-ion microbeam (SIM) is uniquely capable of delivering precisely the predefined number of charged particles (precise doses of radiation) to specific individual cells or sub-cellular targets in situ. No active research in the field concerning the original process of the interaction between low-energy ions and complicated organisms has been reported yet. To address this challenge, the aim of the present design is to further wrestle with multi-dimensional quantitative information from living cells traversed by an exact number of ions real-time rather than endpoints, in the time scale from milliseconds to days.

  14. Ion mediated targeting of cells with nanoparticles

    Science.gov (United States)

    Maheshwari, Vivek; Fu, Jinlong

    2010-03-01

    In eukaryotic cells, Ca^2+ ions are necessary for intracellular signaling, in activity of mitochondria and a variety of other cellular process that have been linked to cell apoptosis, proteins synthesis and cell-cycle regulation. Here we show that Ca^2+ ions, serving as the bio-compatible interface can be used to target Saccharomyces cerevisiae (SaC, baker's yeast), a model eukaryotic cell, with Au nanoparticles (10 nm). The Ca^2+ ions bind to the carboxylic acid groups in the citrate functionalized Au nanoparticles. This transforms the nanoparticles into micron long 1-D branched chain assemblies due to inter-particle dipole-dipole interaction and inter-particle bonding due to the divalent nature of the Ca^2+ ion. A similar transformation is observed with the use of divalent ions Mg^2+, Cd^2+ and Fe^2+. The 1-D assembly aids the interfacing of ion-nanoparticles on the cell by providing multiple contact points. Further monovalent ions such as Na^+ are also effective for the targeting of the cell with nanoparticles. However Na-Au nanoparticles are limited in their deposition as they exist in solution as single particles. The cells remain alive after the deposition process and their vitality is unaffected by the interfacing with ion-nanoparticles.

  15. Charging the quantum capacitance of graphene with a single biological ion channel.

    Science.gov (United States)

    Wang, Yung Yu; Pham, Ted D; Zand, Katayoun; Li, Jinfeng; Burke, Peter J

    2014-05-27

    The interaction of cell and organelle membranes (lipid bilayers) with nanoelectronics can enable new technologies to sense and measure electrophysiology in qualitatively new ways. To date, a variety of sensing devices have been demonstrated to measure membrane currents through macroscopic numbers of ion channels. However, nanoelectronic based sensing of single ion channel currents has been a challenge. Here, we report graphene-based field-effect transistors combined with supported lipid bilayers as a platform for measuring, for the first time, individual ion channel activity. We show that the supported lipid bilayers uniformly coat the single layer graphene surface, acting as a biomimetic barrier that insulates (both electrically and chemically) the graphene from the electrolyte environment. Upon introduction of pore-forming membrane proteins such as alamethicin and gramicidin A, current pulses are observed through the lipid bilayers from the graphene to the electrolyte, which charge the quantum capacitance of the graphene. This approach combines nanotechnology with electrophysiology to demonstrate qualitatively new ways of measuring ion channel currents.

  16. SINGLE-ION CONDUCTIVITY IN POLY(LITHIUM PROPIONATE METHYL SILOXANE)

    Institute of Scientific and Technical Information of China (English)

    FANG Shibi; MA Yanguang; GUO Defan; LI Yongjun; JIANG Yingyan; HUANG Xuejie; CHEN Liquan

    1993-01-01

    Poly(lithium propionate methyl siloxane)as a single-ion carrier source was synthesized.The crosslinked film showed lower lithium ionic conductivity at room temperature (about 10-10S/cm).However,the lithium ionic conductivity was obviously increased by blending with high polar polymers such as polyethylene oxide,poly (methylsiloxane-co-ethylene oxide) and poly (methylsiloxane-g-ethylene oxide).In the blend system a high conductivity of 10-7-10-5Scm-1 at room temperature was obtained and the single-ion conductivity was deeply influenced by the content of the poly(lithium propionate methyl siloxane).The dc ionic conductivity of the flexible crosslinked films is more stable over time.

  17. Probing the Dynamics of a Superradiant Quantum Phase Transition with a Single Trapped Ion.

    Science.gov (United States)

    Puebla, Ricardo; Hwang, Myung-Joong; Casanova, Jorge; Plenio, Martin B

    2017-02-17

    We demonstrate that the quantum phase transition (QPT) of the Rabi model and critical dynamics near the QPT can be probed in the setup of a single trapped ion. We first demonstrate that there exists equilibrium and nonequilibrium scaling functions of the Rabi model by finding a proper rescaling of the system parameters and observables, and show that those scaling functions are representative of the universality class to which the Rabi model belongs. We then propose a scheme that can faithfully realize the Rabi model in the limit of a large ratio of the effective atomic transition frequency to the oscillator frequency using a single trapped ion and, therefore, the QPT. It is demonstrated that the predicted universal functions can indeed be observed based on our scheme. Finally, the effects of realistic noise sources on probing the universal functions in experiments are examined.

  18. Probing the Dynamics of a Superradiant Quantum Phase Transition with a Single Trapped Ion

    Science.gov (United States)

    Puebla, Ricardo; Hwang, Myung-Joong; Casanova, Jorge; Plenio, Martin B.

    2017-02-01

    We demonstrate that the quantum phase transition (QPT) of the Rabi model and critical dynamics near the QPT can be probed in the setup of a single trapped ion. We first demonstrate that there exists equilibrium and nonequilibrium scaling functions of the Rabi model by finding a proper rescaling of the system parameters and observables, and show that those scaling functions are representative of the universality class to which the Rabi model belongs. We then propose a scheme that can faithfully realize the Rabi model in the limit of a large ratio of the effective atomic transition frequency to the oscillator frequency using a single trapped ion and, therefore, the QPT. It is demonstrated that the predicted universal functions can indeed be observed based on our scheme. Finally, the effects of realistic noise sources on probing the universal functions in experiments are examined.

  19. Focused ion beam patterning to dielectrophoretically assemble single nanowire based devices

    Energy Technology Data Exchange (ETDEWEB)

    La Ferrara, V; Massera, E; Francia, G Di [ENEA Research Center, P.le E. Fermi 1, 80055 Portici (Italy); Alfano, B, E-mail: vera.laferrara@portici.enea.i [University of Naples ' Federico II' , P.le Tecchio 80, 80125 Naples (Italy)

    2010-02-01

    Direct-write processing is increasingly taking place in nanodevice fabrication. In this work, Focused Ion Beam (FIB), a powerful tool in maskless micromachining, is used for electrode patterning onto a silicon/silicon nitride substrate. Then a single palladium nanowire is assembled between electrodes by means of dielectrophoresis (DEP). The nanowire morphology depends on the electrode pattern when DEP conditions are fixed. FIB/DEP combination overcomes the problem of nanowire electrical contamination due to gallium ion bombardment and the as-grown nanowire retains its basic electrical properties. Single nanowire based devices have been fabricated with this novel approach and have been tested as hydrogen sensors, confirming the reliability of this technology.

  20. High rate lithium-sulfur battery enabled by sandwiched single ion conducting polymer electrolyte

    OpenAIRE

    Yubao Sun; Gai Li; Yuanchu Lai; Danli Zeng; Hansong Cheng

    2016-01-01

    Lithium-sulfur batteries are highly promising for electric energy storage with high energy density, abundant resources and low cost. However, the battery technologies have often suffered from a short cycle life and poor rate stability arising from the well-known “polysulfide shuttle” effect. Here, we report a novel cell design by sandwiching a sp 3 boron based single ion conducting polymer electrolyte film between two carbon films to fabricate a composite separator for lithium-sulfur batterie...

  1. A generalized Jaynes-Cummings model: The relativistic parametric amplifier and a single trapped ion

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda-Guillén, D., E-mail: dojedag@ipn.mx [Escuela Superior de Cómputo, Instituto Politécnico Nacional, Av. Juan de Dios Bátiz esq. Av. Miguel Othón de Mendizábal, Col. Lindavista, Delegación Gustavo A. Madero, C.P. 07738 Ciudad de México (Mexico); Mota, R. D. [Escuela Superior de Ingeniería Mecánica y Eléctrica, Unidad Culhuacán, Instituto Politécnico Nacional, Av. Santa Ana No. 1000, Col. San Francisco Culhuacán, Delegación Coyoacán, C.P. 04430 Ciudad de México (Mexico); Granados, V. D. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ed. 9, Unidad Profesional Adolfo López Mateos, Delegación Gustavo A. Madero, C.P. 07738 Ciudad de México (Mexico)

    2016-06-15

    We introduce a generalization of the Jaynes-Cummings model and study some of its properties. We obtain the energy spectrum and eigenfunctions of this model by using the tilting transformation and the squeezed number states of the one-dimensional harmonic oscillator. As physical applications, we connect this new model to two important and novelty problems: the relativistic parametric amplifier and the quantum simulation of a single trapped ion.

  2. Irradiation damage in aluminium single crystals produced by 50-keV aluminium and copper ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.

    1968-01-01

    Aluminium single crystals, thin enough to be examined by electron microscopy, have been irradiated with 50-keV aluminium and copper ions. The irradiation fluxes were in the range 1011–1014 cm−2 s−1 and the doses were from 6 × 1012 to 6 × 1014 cm−2. Irradiation along either a or a direction produc...

  3. Influence of Oxygen ions irradiation on Polyaniline/Single Walled Carbon Nanotubes nanocomposite

    Science.gov (United States)

    Patil, Harshada K.; Deshmukh, Megha A.; Gaikwad, Sumedh D.; Bodkhe, Gajanan A.; Asokan, K.; Yasuzawa, Mikito; Koinkar, Pankaj; Shirsat, Mahendara D.

    2017-01-01

    Influence of Oxygen ions (100 MeV) irradiation on Polyaniline (PANI)/Single Walled Carbon Nanotubes (SWNTs) nanocomposite was studied in the present investigation. PANI/SWNTs nanocomposite was synthesized by electrochemical Cyclic Voltammetry technique. Nanocomposite was exposed under SHI irradiation of Oxygen (100 MeV) ions for three different fluences such as 1×1010 ions/cm2, 5×1010 ions/cm2 and 1×1011 ions/cm2. The SHI irradiated PANI/SWNTs nanocomposite was investigated by using morphological (AFM), structural (XRD) and spectroscopy (FTIR) characterization. AFM study exhibits effects of SHI irradiation on morphology of the nanocomposite and root mean square roughness of the nanocomposite is observed to be decreased as fluence was increased. The FTIR absorption spectrum exhibits formation of new functional sites with the increase in intensity of absorption peaks, due to SHI irradiation. X-Ray Diffraction studies show a gradual decrease in the crystalline nature of the nanocomposite upon irradiation.

  4. Single-ion anisotropy and transverse magnetization in the frustrated gadolinium pyrochlores

    Science.gov (United States)

    Glazkov, V. N.; Zhitomirsky, M.; Smirnov, A. I.; Marin, C.; Sanchez, J.-P.; Forget, A.; Colson, D.; Bonville, P.

    2007-04-01

    A single-ion anisotropy of the planar type is found in the pyrochlore antiferromagnet oxides Gd2M2O7 (M = Ti,Sn); its strength is comparable with the strength of the exchange coupling. Models considering the effects of the planar anisotropy predict the appearance of a transverse magnetization in an applied magnetic field. A detailed experimental study of Gd2Ti2O7 single crystals reveals that a transverse magnetization is really present at low temperatures. The magnetic phase diagram of Gd2Ti2O7 is refined.

  5. Heavy Ion Irradiation Fluence Dependence for Single-Event Upsets of NAND Flash Memory

    Science.gov (United States)

    Chen, Dakai; Wilcox, Edward; Ladbury, Raymond; Kim, Hak; Phan, Anthony; Seidleck, Christina; LaBel, Kenneth

    2016-01-01

    We investigated the single-event effect (SEE) susceptibility of the Micron 16 nm NAND flash, and found the single-event upset (SEU) cross section varied inversely with fluence. The SEU cross section decreased with increasing fluence. We attribute the effect to the variable upset sensitivities of the memory cells. The current test standards and procedures assume that SEU follow a Poisson process and do not take into account the variability in the error rate with fluence. Therefore, heavy ion irradiation of devices with variable upset sensitivity distribution using typical fluence levels may underestimate the cross section and on-orbit event rate.

  6. Dispersion coefficients for the interaction of inert gas atoms with alkali and alkaline earth ions and alkali atoms with their singly ionized ions

    CERN Document Server

    Singh, Sukhjit; Sahoo, B K; Arora, Bindiya

    2016-01-01

    We report the dispersion coefficients for the interacting inert gas atoms with the alkali ions, alkaline earth ions and alkali atoms with their singly charged ions. We use our relativistic coupled-cluster method to determine dynamic dipole and quadrupole polarizabilities of the alkali atoms and singly ionized alkaline earth atoms, whereas a relativistic random phase approximation approach has been adopted to evaluate these quantities for the closed-shell configured inert gas atoms and the singly and doubly ionized alkali and alkaline earth atoms, respectively. Accuracies of these results are adjudged from the comparison of their static polarizability values with their respective experimental results. These polarizabilities are further compared with the other theoretical results. Reason for the improvement in the accuracies of our estimated dispersion coefficients than the data listed in [At. Data and Nucl. Data Tables 101, 58 (2015)] are discussed. Results for some of the atom-ion interacting systems were not...

  7. Single-Ion Atomic Clock with $3\\times10^{-18}$ Systematic Uncertainty

    CERN Document Server

    Huntemann, N; Lipphardt, B; Tamm, Chr; Peik, E

    2016-01-01

    We experimentally investigate an optical frequency standard based on the $^2S_{1/2} (F=0)\\to {}^2F_{7/2} (F=3)$ electric octupole (\\textit{E}3) transition of a single trapped $^{171}$Yb$^+$ ion. For the spectroscopy of this strongly forbidden transition, we utilize a Ramsey-type excitation scheme that provides immunity to probe-induced frequency shifts. The cancellation of these shifts is controlled by interleaved single-pulse Rabi spectroscopy which reduces the related relative frequency uncertainty to $1.1\\times 10^{-18}$. To determine the frequency shift due to thermal radiation emitted by the ion's environment, we measure the static scalar differential polarizability of the \\textit{E}3 transition as $0.888(16)\\times 10^{-40}$ J m$^2$/V$^2$ and a dynamic correction $\\eta(300~\\text{K})=-0.0015(7)$. This reduces the uncertainty due to thermal radiation to $1.8\\times 10^{-18}$. The residual motion of the ion yields the largest contribution $(2.1\\times 10^{-18})$ to the total systematic relative uncertainty of...

  8. A Single Charge State ECR Ion Source%单粒子态ECR离子源

    Institute of Scientific and Technical Information of China (English)

    赵玉彬; 刘占稳; 赵红卫; 丁俊章; 曹云; 张子民; 张雪珍; 郭晓虹

    1999-01-01

    A compact 2.45GHz electron cyclotron resonance ion source (ECRIS) for high beam current of single charge state has been built at Institute of Modern Physics. A mixed ion( )beam current of 90mA is delivered from a single aperture of φ6mm with rf power 600W at extraction voltage 22kV. This paper introduces the source structure, the magnetic configuration, the test results and the relation between the magnetic configuration and total beam current. In addition, the magnetic configuration is also compared with that of the other 2.45GHz ECR ion sources built in different laboratories. Finally, some conclusions are presented.%介绍了一台2.45GHz电子回旋共振(ECR)单电荷离子源的磁场场形,以及它和总束流的关系. 并且比较了国际上现有的几台同类型离子源的磁场场形. 由此得出了关于2.45GHz ECR 离子源磁场场形的一些结论.

  9. Single-Ion Atomic Clock with 3×10(-18) Systematic Uncertainty.

    Science.gov (United States)

    Huntemann, N; Sanner, C; Lipphardt, B; Tamm, Chr; Peik, E

    2016-02-12

    We experimentally investigate an optical frequency standard based on the (2)S1/2(F=0)→(2)F7/2(F=3) electric octupole (E3) transition of a single trapped (171)Yb+ ion. For the spectroscopy of this strongly forbidden transition, we utilize a Ramsey-type excitation scheme that provides immunity to probe-induced frequency shifts. The cancellation of these shifts is controlled by interleaved single-pulse Rabi spectroscopy, which reduces the related relative frequency uncertainty to 1.1×10(-18). To determine the frequency shift due to thermal radiation emitted by the ion's environment, we measure the static scalar differential polarizability of the E3 transition as 0.888(16)×10(-40)  J m(2)/V(2) and a dynamic correction η(300  K)=-0.0015(7). This reduces the uncertainty due to thermal radiation to 1.8×10(-18). The residual motion of the ion yields the largest contribution (2.1×10(-18)) to the total systematic relative uncertainty of the clock of 3.2×10(-18).

  10. Effect of swift heavy ion irradiation on single- and multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Olejniczak, Andrzej, E-mail: aolejnic@chem.uni.torun.pl [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, 87-100 Toruń (Poland); Skuratov, Vladimir A. [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)

    2014-05-01

    The effect of irradiation with swift heavy ions on the structure and properties of carbon nanotubes was investigated by Raman spectroscopy. It was found that disordering of the system occurred mainly at the surface. No ordering phenomena have been observed over a whole range of both fluences and electronic stopping powers studied. The disorder parameter (i.e., the ratio of the D and G band intensities (I{sub D}/I{sub G})) increases non-linearly with the irradiation dose, showing a tendency to saturate at high fluences. The increase in the disorder parameter upon irradiation was proportional to the square root of the ion fluence. The radiation stability of the few-walled nanotubes was ca. 1.6 higher than that of the single-walled ones. The irradiation with both the Xe and Kr ions leads to essentially the same increase in the I{sub D}/I{sub G} ratio with respect to the deposited electronic energy density. In the case of the Ar ion irradiation, the observed increase in the I{sub D}/I{sub G} ratio is much lower, suggesting that the electronic stopping power threshold for defects creation in carbon nanotubes is lower than that for graphite.

  11. Enhanced adsorption of mercury ions on thiol derivatized single wall carbon nanotubes.

    Science.gov (United States)

    Bandaru, Narasimha Murthy; Reta, Nekane; Dalal, Habibullah; Ellis, Amanda V; Shapter, Joseph; Voelcker, Nicolas H

    2013-10-15

    Thiol-derivatized single walled carbon nanotube (SWCNT-SH) powders were synthesized by reacting acid-cut SWCNTs with cysteamine hydrochloride using carbodiimide coupling. Infrared (IR) spectroscopy, Raman spectroscopy and thermogravimetric analysis confirmed the successful functionalization of the SWCNTs. SWCNT-SH powders exhibited a threefold higher adsorption capacity for Hg(II) ions compared to pristine SWCNTs, and a fourfold higher adsorption capacity compared to activated carbon. The influence of adsorption time, pH, initial metal concentration and adsorbent dose on Hg(II) ion removal was investigated. The maximum adsorption capacity of the SWCNT-SH powders was estimated by using equilibrium isotherms, such as Freundlich and Langmuir, and the maximum adsorption capacity of the SWCNT-SH powder was found to be 131 mg/g. A first-order rate model was employed to describe the kinetic adsorption process of Hg(II) ions onto the SWCNT-SH powders. Desorption studies revealed that Hg(II) ions could be easily removed from the SWCNT-SH powders by altering the pH. Further, the adsorption efficiency of recovered SWCNT-SH powders was retained up to 91%, even after 5 adsorption/desorption cycles.

  12. Persistent photoconductivity in oxygen-ion implanted KNbO3 bulk single crystal

    Science.gov (United States)

    Tsuruoka, R.; Shinkawa, A.; Nishimura, T.; Tanuma, C.; Kuriyama, K.; Kushida, K.

    2016-12-01

    Persistent Photoconductivity (PPC) in oxygen-ion implanted KNbO3 ([001] oriented bulk single crystals; perovskite structure; ferroelectric with a band gap of 3.16 eV) is studied in air at room temperature to prevent the degradation of its crystallinity caused by the phase transition. The residual hydrogens in un-implanted samples are estimated to be 5×1014 cm-2 from elastic recoil detection analysis (ERDA). A multiple-energy implantation of oxygen ions into KNbO3 is performed using energies of 200, 400, and 600 keV (each ion fluence:1.0×1014 cm-2). The sheet resistance varies from >108 Ω/□ for an un-implanted sample to 1.9×107 Ω/□ for as-implanted one, suggesting the formation of donors due to hydrogen interstitials and oxygen vacancies introduced by the ion implantation. The PPC is clearly observed with ultraviolet and blue LEDs illumination rather than green, red, and infrared, suggesting the release of electrons from the metastable conductive state below the conduction band relating to the charge states of the oxygen vacancy.

  13. Live cell imaging combined with high-energy single-ion microbeam.

    Science.gov (United States)

    Guo, Na; Du, Guanghua; Liu, Wenjing; Guo, Jinlong; Wu, Ruqun; Chen, Hao; Wei, Junzhe

    2016-03-01

    DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10(-3) s(-1) and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10(-2) s(-1).

  14. Live cell imaging combined with high-energy single-ion microbeam

    Science.gov (United States)

    Guo, Na; Du, Guanghua; Liu, Wenjing; Guo, Jinlong; Wu, Ruqun; Chen, Hao; Wei, Junzhe

    2016-03-01

    DNA strand breaks can lead to cell carcinogenesis or cell death if not repaired rapidly and efficiently. An online live cell imaging system was established at the high energy microbeam facility at the Institute of Modern Physics to study early and fast cellular response to DNA damage after high linear energy transfer ion radiation. The HT1080 cells expressing XRCC1-RFP were irradiated with single high energy nickel ions, and time-lapse images of the irradiated cells were obtained online. The live cell imaging analysis shows that strand-break repair protein XRCC1 was recruited to the ion hit position within 20 s in the cells and formed bright foci in the cell nucleus. The fast recruitment of XRCC1 at the ion hits reached a maximum at about 200 s post-irradiation and then was followed by a slower release into the nucleoplasm. The measured dual-exponential kinetics of XRCC1 protein are consistent with the proposed consecutive reaction model, and the measurements obtained that the reaction rate constant of the XRCC1 recruitment to DNA strand break is 1.2 × 10-3 s-1 and the reaction rate constant of the XRCC1 release from the break-XRCC1 complex is 1.2 × 10-2 s-1.

  15. Single discharge of the matrix source of negative hydrogen ions: Influence of the neutral particle dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Paunska, Ts.; Todorov, D., E-mail: dimitar-tdrv@phys.uni-sofia.bg; Shivarova, A. [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Tarnev, Kh. [Department of Applied Physics, Technical University–Sofia, BG-1000 Sofia (Bulgaria)

    2015-04-08

    The study presents two-dimensional (2D) fluid-plasma-model description of a planar-coil inductively-driven discharge, considered as a single element of a matrix source of volume-produced negative hydrogen ions. Whereas the models developed up to now have been directed towards description of the charged particle behavior in the discharge, including that of the negative ions, this model stresses on the role of the neutral particle dynamics and of the surface processes in the formation of the discharge structure. The latter is discussed based on comparison of results obtained for discharges in a flowing gas and at a constant gas pressure as well as for different values of the coefficient of atom recombination on the walls. The conclusions are that the main plasma parameters – electron density and temperature and plasma potential – determining the gas discharge regime stay stable, regardless of changes in the redistribution of the densities of the neutral particles and of the positive ions. With regards to the volume production of the ions, which requires high density of (vibrationally excited) molecules, the impact on the degree of dissociation of the coefficient of atom recombination on the wall is discussed.

  16. Investigating the efficacy of monovalent and tetravalent dengue vaccine formulations against DENV-4 challenge in AG129 mice.

    Science.gov (United States)

    Fuchs, Jeremy; Chu, Haiyan; O'Day, Peter; Pyles, Richard; Bourne, Nigel; Das, Subash C; Milligan, Gregg N; Barrett, Alan D T; Partidos, Charalambos D; Osorio, Jorge E

    2014-11-12

    Dengue (DEN) is the most important mosquito-borne viral disease, with a major impact on global health and economics, caused by four serologically and distinct viruses termed DENV-1 to DENV-4. Currently, there is no licensed vaccine to prevent DEN. We have developed a live attenuated tetravalent DENV vaccine candidate (TDV) (formally known as DENVax) that has shown promise in preclinical and clinical studies and elicits neutralizing antibody responses to all four DENVs. As these responses are lowest to DENV-4 we have used the AG129 mouse model to investigate the immunogenicity of monovalent TDV-4 or tetravalent TDV vaccines, and their efficacy against lethal DENV-4 challenge. Since the common backbone of TDV is based on an attenuated DENV-2 strain (TDV-2) we also tested the efficacy of TDV-2 against DENV-4 challenge. Single doses of the tetravalent or monovalent vaccines elicited neutralizing antibodies, anti-NS1 antibodies, and cellular responses to both envelope and nonstructural proteins. All vaccinated animals were protected against challenge at 60 days post-immunization, whereas all control animals died. Investigation of DENV-4 viremias post-challenge showed that only the control animals had high viremias on day 3 post-challenge, whereas vaccinated mice had no detectable viremia. Overall, these data highlight the excellent immunogenicity and efficacy profile of our candidate dengue vaccine in AG129 mice.

  17. Swift heavy ion induced modifications of single walled carbon nanotube thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vishalli, E-mail: vishalli_2008@yahoo.com [Department of Physics, Panjab University, Chandigarh 160014 (India); Raina, K.K. [Materials Research Laboratory, School of Physics and Materials Science, Thapar University, P.O. Box 32, Patiala 147004, Punjab (India); Avasthi, D.K. [Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, P.O. Box 10502, New Delhi 110067 (India); Srivastava, Alok [Department of Chemistry, Panjab University, Chandigarh 160014 (India); Dharamvir, Keya [Department of Physics, Panjab University, Chandigarh 160014 (India)

    2016-04-15

    Thin films of single walled carbon nanotubes (SWCNTs) were prepared by Langmuir–Blodgett method and irradiated with swift heavy ions, carbon and nickel each of energy 60 MeV. The ion beams have different electronic energy loss (S{sub e}) values and the samples were exposed to various irradiation doses. The irradiated films were characterized using Raman and optical absorption spectroscopy. Raman spectroscopy results indicate the competing processes of defect creation and healing (annealing) of SWCNTs at lower fluences, while at higher fluences defect creation or damage dominates. In UV–Vis–NIR spectroscopy we find that there is decrease in the intensity of characteristic peaks with every increasing fluence, indicating decrease in the optically active states with irradiation.

  18. A critical test for distorted wave theories: laser-assisted single ionization by ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Ciappina, Marcelo [Max-Planck-Institut fuer Physik Komplexer Systeme, Dresden (Germany); Madsen, Lars Bojer [Department of Physics and Astronomy, Univ. of Aarhus (Denmark)

    2008-07-01

    We study single ionization in laser-assisted high-energy non-relativistic ion-atom collisions and show that the low-energy angular differential electron spectrum may be enhanced significantly by a weak external field. With increasing the strength of the assisting field, the energy spectrum develops a plateau with a characteristic cut-off. In the plateau region we predict distinct multiphoton peaks separated by the photon-energy of the laser field. In the present laser-assisted continuum-distorted-wave eikonal-initial-state (LA-CDW-EIS) theory, this effect may be related to the dynamics in the two-body electron-projectile subsystem. The combined process where an electron is ionized by a heavy ion and subsequently moves in the laser field and under the influence of the Coulomb fields of the projectile and the target represents a stringent test for distorted wave theories.

  19. Magnetic anisotropy in surface-supported single-ion lanthanide complexes

    CERN Document Server

    Stoll, Paul; Rolf, Daniela; Nickel, Fabian; Xu, Qingyu; Hartmann, Claudia; Umbach, Tobias R; Kopprasch, Jens; Ladenthin, Janina N; Schierle, Enrico; Weschke, Eugen; Czekelius, Constantin; Kuch, Wolfgang; Franke, Katharina J

    2016-01-01

    Single-ion lanthanide-organic complexes can provide stable magnetic moments with well-defined orientation for spintronic applications on the atomic level. Here, we show by a combined experimental approach of scanning tunneling microscopy and X-ray absorption spectroscopy that dysprosium-tris(1,1,1-trifluoro-4-(2-thienyl)-2,4butanedionate) (Dy(tta)$_3$) complexes deposited on a Au(111) surface undergo a molecular distortion, resulting in distinct crystal field symmetry imposed on the Dy ion. This leads to an easy-axis magnetization direction in the ligand plane. Furthermore, we show that tunneling electrons hardly couple to the spin excitations, which we ascribe to the shielded nature of the $4f$ electrons.

  20. A Miniaturized Linear Wire Ion Trap with Electron Ionization and Single Photon Ionization Sources

    Science.gov (United States)

    Wu, Qinghao; Tian, Yuan; Li, Ailin; Andrews, Derek; Hawkins, Aaron R.; Austin, Daniel E.

    2017-05-01

    A linear wire ion trap (LWIT) with both electron ionization (EI) and single photon ionization (SPI) sources was built. The SPI was provided by a vacuum ultraviolet (VUV) lamp with the ability to softly ionize organic compounds. The VUV lamp was driven by a pulse amplifier, which was controlled by a pulse generator, to avoid the detection of photons during ion detection. Sample gas was introduced through a leak valve, and the pressure in the system is shown to affect the signal-to-noise ratio and resolving power. Under optimized conditions, the limit of detection (LOD) for benzene was 80 ppbv using SPI, better than the LOD using EI (137 ppbv). System performance was demonstrated by distinguishing compounds in different classes from gasoline.

  1. Single palladium nanowire growth in place assisted by dielectrophoresis and focused ion beam.

    Science.gov (United States)

    La Ferrara, Vera; Alfano, Brigida; Massera, Ettore; Di Francia, Girolamo

    2009-05-01

    Here we report, for the first time, on the combined use of Focused Ion Beam and Dielectrophoresis techniques for the fabrication of a nanodevice whose operating mechanism relies on a single palladium nanowire. Focused Ion Beam is used to deposit, without photolithographic masks, platinum microelectrodes on a silicon/silicon nitride substrate. Dielectrophoresis is employed for assembling the palladium nanowire, starting from a saturated palladium particles solution, and precisely positioning it between the nanocontacts. The nanodevice works as a hydrogen sensor, confirming the reliability of technology. Its electrical response has been recorded, at room temperature, in a dynamic environment, where different hydrogen concentrations, from 0.1% to 4% in dry air, have been introduced. Its sensitivity, towards 0.1% to 1% gas concentrations in dry air, has been calculated, too.

  2. On the calculation of single ion activity coefficients in homogeneous ionic systems by application of the grand canonical ensemble

    DEFF Research Database (Denmark)

    Sloth, Peter

    1993-01-01

    The grand canonical ensemble has been used to study the evaluation of single ion activity coefficients in homogeneous ionic fluids. In this work, the Coulombic interactions are truncated according to the minimum image approximation, and the ions are assumed to be placed in a structureless, homoge...

  3. Critical Properties of Mixed Ising Spin System with Different Trimodal Transverse Fields in the Presence of Single-Ion Anisotropy

    Institute of Scientific and Technical Information of China (English)

    CHEN Qiang; YAN Shi-Lei

    2006-01-01

    Within the framework of an effective field approximation, the effects of single-ion anisotropy and different trimodal transverse fields of two sublattices on the critical properties of the mixed spin-1/2 and spin-1 Ising system are investigated on the simple cubic lattice. A smaller single-ion anisotropy can magnify magnetic ordering phases and a larger one can depress magnetic ordering phase for T-Ω1/2 space at low temperatures, while a smaller single-ion anisotropy can hardly change the value of critical transverse field for T-Ω1 space. On the other hand, influences of two different trimodal transverse fields concentrations on tricritical points and magnetic ordering phases take on some interesting results in T-D space. The main reason comes from the common action of single-ion anisotropy, different transverse fields and two trimodal distributions.

  4. Dissociation of the store-operated calcium current ICRAC and the Mg-nucleotide-regulated metal ion current MagNuM

    Science.gov (United States)

    Hermosura, Meredith C; Monteilh-Zoller, Mahealani K; Scharenberg, Andrew M; Penner, Reinhold; Fleig, Andrea

    2002-01-01

    Rat basophilic leukaemia cells (RBL-2H3-M1) were used to study the characteristics of the store-operated Ca2+ release-activated Ca2+ current (ICRAC) and the magnesium-nucleotide-regulated metal cation current (MagNuM) (which is conducted by the LTRPC7 channel). Pipette solutions containing 10 mm BAPTA and no added ATP induced both currents in the same cell, but the time to half-maximal activation for MagNuM was about two to three times slower than that of ICRAC. Differential suppression of ICRAC was achieved by buffering free [Ca2+]i to 90 nm and selective inhibition of MagNuM was accomplished by intracellular solutions containing 6 mm Mg.ATP, 1.2 mm free [Mg2+]i or 100 μm GTP-γ-S, allowing investigations on these currents in relative isolation. Removal of extracellular Ca2+ and Mg2+ caused both currents to be carried significantly by monovalent ions. In the absence or presence of free [Mg2+]i, ICRAC carried by monovalent ions inactivated more rapidly and more completely than MagNuM carried by monovalent ions. Since several studies have used divalent-free solutions on either side of the membrane to study selectivity and single-channel behaviour of ICRAC, these experimental conditions would have favoured the contribution of MagNuM to monovalent conductance and call for caution in interpreting results where both ICRAC and MagNuM are activated. PMID:11882677

  5. Single-ion microbeam as a tool for low-dose radiation effects investigations

    Energy Technology Data Exchange (ETDEWEB)

    Gerardi, Silvia [INFN - Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Galeazzi, Giuseppe [INFN - Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Cherubini, Roberto [INFN - Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy)

    2006-05-15

    Practical assessment of human radiation exposure risk deserves particular attention especially for low doses (and low dose rates), which concern environmental and occupational exposure. At these dose levels ionizing radiation exposures involve mainly isolated charged particle tracks, which strike individual cells at time intervals averaging from weeks to several years apart. Accelerator-based microbeam irradiation technique offers a unique tool to mimic such an exposure, allowing irradiating single cells individually with micrometer precision and with a preset number of charged particles down to one particle per cell. A horizontal single-ion microbeam facility for single-cell irradiations has been designed and set up at the INFN-LNL 7MV CN Van de Graaff accelerator. The light ion beam is collimated in air down to a section of 2-3{mu}m in diameter by means of appropriate pinholes. Semi-automatic cell visualization and automatic cell positioning and revisiting system, based on an inverted phase contrast optical microscope and on X-Y translation stages with 0.1{mu}m positioning precision, has been developed. An in-house-written software allows to control remotely the irradiation protocol. As a distinctive feature of the facility, cell recognition is performed without using fluorescent staining and UV light. Particle detection in air, behind the biological sample, is based on a silicon detector while in-air beam profile and precise hit position measurements are accomplished by a custom-made cooled-CCD camera and Solid State Nuclear Track detectors, respectively. A particle counting rate of less than 1 ion/sec can be reached.

  6. Potent dengue virus neutralization by a therapeutic antibody with low monovalent affinity requires bivalent engagement.

    Directory of Open Access Journals (Sweden)

    Melissa A Edeling

    2014-04-01

    Full Text Available We recently described our most potently neutralizing monoclonal antibody, E106, which protected against lethal Dengue virus type 1 (DENV-1 infection in mice. To further understand its functional properties, we determined the crystal structure of E106 Fab in complex with domain III (DIII of DENV-1 envelope (E protein to 2.45 Å resolution. Analysis of the complex revealed a small antibody-antigen interface with the epitope on DIII composed of nine residues along the lateral ridge and A-strand regions. Despite strong virus neutralizing activity of E106 IgG at picomolar concentrations, E106 Fab exhibited a ∼20,000-fold decrease in virus neutralization and bound isolated DIII, E, or viral particles with only a micromolar monovalent affinity. In comparison, E106 IgG bound DENV-1 virions with nanomolar avidity. The E106 epitope appears readily accessible on virions, as neutralization was largely temperature-independent. Collectively, our data suggest that E106 neutralizes DENV-1 infection through bivalent engagement of adjacent DIII subunits on a single virion. The isolation of anti-flavivirus antibodies that require bivalent binding to inhibit infection efficiently may be a rare event due to the unique icosahedral arrangement of envelope proteins on the virion surface.

  7. Deposition of diamond like carbon films by using a single ion gun with varying beam source

    Institute of Scientific and Technical Information of China (English)

    JIANG Jin-qiu; Chen Zhu-ping

    2001-01-01

    Diamond like carbon films have been successfully deposited on the steel substrate, by using a single ion gun with varying beam source. The films may appear blue, yellow and transparent in color, which was found related to contaminants from the sample holder and could be avoided. The thickness of the films ranges from tens up to 200 nanometers, and the hardness is in the range 20 to 30 GPa. Raman analytical results reveal the films are in amorphous structure. The effects of different beam source on the films structure are further discussed.

  8. Determining single-ion and spatial exchange anisotropies by pulsed-field magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Manson, J. L. [Chemistry, Eastern Wash. U.; Villa, J. A. [Chemistry, Eastern Wash. U.; Singleton, John [Los Alamos National Laboratory; Brambleby, J. [Physics, U. of Warwick; Goddard, P. A. [Physics, U. of Warwick

    2017-02-13

    The magnetic ground-state of the Q1D S = 1 antiferromagnetic (AFM) chain is sensitive to the single-ion anisotropy (D) and the relative strength of intra- (J) and interchain (J’) exchange interactions. The ratios D/J and J’/J dictate the material’s placement on the phase diagram for which three competing phases are known to theoretically exist: Haldane, XY and quantum paramagnetic. We identified [Ni(HF2)(pyz)2]SbF6 (pyz = pyrazine) as a candidate in which to explore proximity to these phases.

  9. Field-ion microscopy observation of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    张兆祥; 张耿民; 杜民; 金新喜; 侯士敏; 孙建平; 顾镇南; 赵兴钰; 刘惟敏; 吴锦雷; 薛增泉

    2002-01-01

    Field-ion microscopy (FIM), a tool for surface analysis with atomic resolution, has been employed to observethe end structure of single-walled carbon nanotubes (SWCNTs). FIM images revealed the existence of open SWCNTends. Amorphous carbon atoms were also observed to occur around SWCNTs and traditional field evaporation failedto remove them. Heat treatment was found to be efficacious in altering the end structures of SWCNT bundles. Carbonand oxygen atoms released from heated tungsten filament are believed to be responsible for the decoration imposed onthe SWCNT ends.

  10. Single Cell Element of Chalcogenide Random Access Memory Fabricated with the Focused Ion Beam Method

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; SONG Zhi-Tang; FENG Song-Lin; CHEN Bomy

    2004-01-01

    A single cell element of chalcogenide random access memory was fabricated by using the focused ion beam method. The contact size between the Ge2Sb2 Te5 phase change film and the top electrode film is about 600nm (diameter) and the contact area is calculated to be 0.28pm2. The thickness of the phase change film is 83nm.The current-voltage characteristics of the cell element are studied using the home-made current-voltage tester in our laboratory. The minimum threshold current of about 0.6mA is obtained.

  11. Experimental Study of Single- and Double-Electron Detachment for Negative Carbon Ions Incident on Helium

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-Yi; WU Shi-Min; ZHANG Xue-Mei; LI Guang-Wu; LU Fu-Quan; YANG Fu-Jia

    2004-01-01

    Using the growth rate method, we obtain the single-electron detachment (SED) cross-sections for 5-30keV C-+He, and double-electron detachment (DED) cross-sections for 5-15keV C--+He. The SED cross-sections first increase with the increasing incident ion energy, and then decrease with further increase of the energy. The DED cross-sections increase with the increasing incident energy in the 5-15keV region.

  12. Spatial distribution of particles sputtered from single crystals by gas cluster ions

    Science.gov (United States)

    Nazarov, A. V.; Chernysh, V. S.; Nordlund, K.; Djurabekova, F.; Zhao, J.

    2017-09-01

    The results of molecular dynamics simulations of the bombardment of the Cu (100) and Mo (100) single-crystals by 10 keV Ar cluster ions of different sizes are presented in this paper. Spatial distributions of sputtered material were calculated. The anisotropy of the angular distributions of sputtered atoms was revealed. It was found that the character of the anisotropy is different for Cu and Mo targets. The reasons leading to this anisotropy are discussed according to the dependences of the angular distributions on the cluster size and on the target material.

  13. Rational Design of Lanthanoid Single-Ion Magnets: Predictive Power of the Theoretical Models.

    Science.gov (United States)

    Baldoví, José J; Duan, Yan; Morales, Roser; Gaita-Ariño, Alejandro; Ruiz, Eliseo; Coronado, Eugenio

    2016-09-12

    We report two new single-ion magnets (SIMs) of a family of oxydiacetate lanthanide complexes with D3 symmetry to test the predictive capabilities of complete active space ab initio methods (CASSCF and CASPT2) and the semiempirical radial effective charge (REC) model. Comparison of the theoretical predictions of the energy levels, wave functions and magnetic properties with detailed spectroscopic and magnetic characterisation is used to critically discuss the limitations of these theoretical approaches. The need for spectroscopic information for a reliable description of the properties of lanthanide SIMs is emphasised.

  14. Heavy Ion Induced Single Event Upsets on 65 nm Advanced CMOS Technology SRAM

    Institute of Scientific and Technical Information of China (English)

    CAI; Li; GAO; Li-juan; SHI; Shu-ting; LIU; Jian-cheng; WANG; Hui; FAN; Hui

    2012-01-01

    <正>With rapid development of semiconductor industry, the problem of single event effects (SEE) has become exacerbated with shrinking technology feature size and power supply voltages. Accompanying smaller technology scaling is closer spacing between transistors, smaller sensitive areas requiring less critical charge to upset, and lower power supply voltages resulting in a smaller critical charge (Qcrit) to upset. Experimental assessment of circuit sensitivity to radiation is of the most importance. And in this paper we studied the heavy ion characterization on 65 nm advanced CMOS technology SRAM.

  15. Conductometric determination of single pores in polyethyleneterephthalate irradiated by heavy ions

    CERN Document Server

    Oganesyan, V R; Dörschel, B; Hermsdorf, D; Trofimov, V V; Vetter, J

    2002-01-01

    Most of the previous works devoted to the problem of track formation processes did not pay enough attention to direct measurement of the appearance of every individual pore in an array of many pores induced by the irradiation of polymer films with ions. Such measurements are not easy to carry out due to the extremely high electric resistance in the moment of pore opening. In this work the analysis of films irradiated with low particle fluences up to 3.7 centre dot 10 sup 3 ions/cm sup 2 is described. Polyethyleneterephthalate (PET) Hostaphan with a thickness of 20 mu m was used. The samples were irradiated with Bi ions of 11.4 MeV/amu energy. Using optimized etching conditions and computer aided data evaluation, we obtained results, which are in good agreement with theoretical predictions and model calculations. The measured increase of conductivity beginning from the breakthrough of a single track up to the next pore opening in dependence on the etching time and the number of opened pores confirm the assumed...

  16. Conductometric Determination of Single Pores in Polyethyleneterephthalate Irradiated by Heavy Ions

    CERN Document Server

    Oganesyan, V R; Dörschel, B; Vetter, J E; Danziger, M; Hermsdorf, D

    2002-01-01

    Most of previous works devoted to the problem of track formation processes did not pay enough attention to direct measurement of the appearance of every individual pore in an array of many pores induced by the irradiation of polymer films with ions. Such measurements are not easy to carry out due to the extremely high electric resistance in the moment of pore opening. In this work the analysis of films irradiated with low particle fluences up to 3.7\\cdot 10^{3} ions/cm^2 is described. Polyethyleneterephthalate (PET) Hostaphan with a thickness of 20 m was used. The samples were irradiated with Bi ions of 11.4 MeV/amu energy. Using optimized etching conditions and computer aided data evaluation we obtained results, which are in good agreement with theoretical predictions and model calculations. The measured increase of conductivity beginning from the breakthrough of a single track up to the next pore opening in dependence on the etching time and the number of opened pores confirm the assumed model. Thus, the de...

  17. Reversible Sodium Ion Insertion in Single Crystalline Manganese Oxide Nanowires with Long Cycle Life

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yuliang; Xiao, Lifen; Wang, Wei; Choi, Daiwon; Nie, Zimin; Yu, Jianguo; Saraf, Laxmikant V.; Yang, Zhenguo; Liu, Jun

    2011-07-26

    Single crystalline Na4Mn9O18 nanowires were synthesized via pyrolysis of polyacrylate salt precursors prepared by in-situ polymerization of the metal salts and acrylate acid, followed by calcinations at an appropriate temperature to achieve good crystalline structure and uniform nanowire morphology with an average diameter of 50 nm. The Na4Mn9O18 nanowires have shown a high, reversible, and near theoretical sodium ion insertion capacity (128 mA h g-1 at 0.1C), excellent long cyclability (77% capacity retention for 1000 cycles at 0.5 C), along with good rate capability. Good capacity and charge-discharge stability are also observed for full cell experiments using a pyrolyzed carbon as the anode, therefore demonstrating the potential of these materials for sodium-ion batteries for large scale energy storage. Furthermore, this research shows that a good crystallinity and small particles are required to enhance the Na-ion diffusion and increase the stability of the electrode materials for long charge-discharge cycles.

  18. FePt nanoparticle formation with lower phase transition temperature by single shot plasma focus ion irradiation

    Science.gov (United States)

    Lin, J. J.; Roshan, M. V.; Pan, Z. Y.; Verma, R.; Lee, P.; Springham, S. V.; Tan, T. L.; Rawat, R. S.

    2008-07-01

    Uniform FePt nanoparticles were synthesized through nanostructuring of pulsed laser deposited FePt thin films by single shot H+ ion irradiation using a plasma focus device. The annealing temperature required for phase transition from low Ku face-centred cubic to high Ku face-centred tetragonal, for ion irradiated samples, is simultaneously lowered down to 400 °C. The energetic H+ ion irradiation significantly reduces the activation energy for atomic ordering by increasing the number of vacancies. The advantage of using a plasma focus device is that it can achieve nanostructuring in much shorter time, in single shot ion exposure with pulse duration of typically about a few hundreds of nanoseconds, as compared with much longer duration required by continuous ion sources.

  19. Pd+ ions in NaCl single crystal: EPR and optical studies

    Science.gov (United States)

    Badalyan, A. G.; Polak, K.; Rosa, J.

    2003-01-01

    EPR and optical absorption of Pd centres in as grown NaCl single crystal are reported. The EPR spectra show that palladium forms the Pd+ centre with d(x2-y2) wave function in the ground state. This centre formation and the accompanying distortion give rise to a superhyperfine interaction of the Pd+ ion with the nuclei of the four Cl- ligands in the plane perpendicular to the C-4 Symmetry axis. The results of the fitting of axial spin Hamiltonian parameters to the experimentally observed spectra give the following values at 12 K: g(parallel to) =2.85, g(perpendicular to) congruent to 2.15, A(parallel to) 29.8 x 10(-4)cm(-1), A(perpendicular to) = 5.9 x 10(-4)cm(-1). When the temperature increases, lines are getting broader, their amplitude decreases and a single line with g-value of g = 2.38 at g = 1/3(g(parallel to)+ 2g(perpendicular to)) appears, which demonstrates the known Jahn-Teller behaviour of d(9) ions EPR spectra.

  20. Electrochemically engineered single Li-ion conducting solid polymer electrolyte on titania nanotubes for microbatteries

    Science.gov (United States)

    Ferrari, I. V.; Braglia, M.; Djenizian, T.; Knauth, P.; Di Vona, M. L.

    2017-06-01

    Single Li-ion conducting p-sulfonated poly(allyl phenyl ether) (SPAPE) is electrochemically synthesized directly on TiO2 nanotubes in the range of -1.5 to -1.8 V vs. Ag/AgCl. The electrochemical deposition conditions are studied by cyclic voltammetry and chronoamperometry; the polymer formation can be followed by electrochemical impedance spectroscopy. The polymer structure is analyzed by NMR and FTIR spectroscopies, showing the formation of linear aliphatic chains with methyl-oxy-benzene sulfonate side groups. SEM observations of the polymer morphology show that a thin (∼300 nm) and continuous layer is obtained depending on the electrochemical synthesis conditions. The combination of a mobile aliphatic backbone, ether groups with reduced cation affinity and immobile anions grafted on the side chains allows obtaining a single lithium-ion conducting polymer. Half-cell battery tests against Li metal show an excellent cycling performance with high areal capacity (up to 110 μAh cm-2) and very good retention especially at large C-rates, studied up to 12 C.

  1. Modern applications of high energy ion beams: From "single-event burnout" to human eye cancer treatment

    Science.gov (United States)

    Homeyer, H.; Mahnke, H.-E.

    1996-12-01

    Energetic ion beams, originally the domain of nuclear physics, become increasingly important tools in many other fields of research and development. The choice of ion species and ion energy allows an enormously wide variation of the penetration depth and of the amount of the electronic stopping power. These features are utilized to modify or damage materials and living tissues in a specific way. Materials modification with energetic ion beams is one of the central aims of research and development at the ion beam laboratory, ISL-Berlin, a center for ion-beam applications at the Hahn-Meitner-Institut Berlin. In particular, energetic protons will be used for eye cancer treatment. Selected topics such as the "single-event burnout" of high power diodes and the eye cancer therapy setup will be presented in detail.

  2. Determination and shaping of the ion-velocity distribution function in a single-ended Q machine

    DEFF Research Database (Denmark)

    Andersen, S.A.; Jensen, Vagn Orla; Michelsen, Poul

    1971-01-01

    An electrostatic energy analyzer with a resolution better than 0.03 eV was constructed. This analyzer was used to determine the ion-velocity distribution function at different densities and plate temperatures in a single-ended Q machine. In all regions good agreement with theoretical predictions......% in single-ended Q machines...

  3. Coordination behaviour and two-dimensional-network formation in poly[[mu-aqua-diaqua(mu5-propane-1,3-diyldinitrilotetraacetato)dilithium(I)cobalt(II)] dihydrate]: the first example of an M(II)-1,3-pdta complex with a monovalent metal counter-ion.

    Science.gov (United States)

    Rychlewska, Urszula; Warzajtis, Beata; Djuran, Milos I; Radanović, Dusanka D; Dimitrijević, Mirjana Dj; Rajković, Sneaeana

    2008-06-01

    The title compound, {[CoLi2(C11H14N2O8)(H2O)3].2H2O}n, constitutes the first example of a salt of the [M(II)(1,3-pdta)](2-) complex (1,3-pdta is propane-1,3-diyldinitrilotetraacetate) with a monopositive cation as counter-ion. Insertion of the Li+ cation could only be achieved through application of the ion-exchange column technique which, however, appeared unsuccessful with other alkali metals and the ammonium cation. The structure contains two tetrahedrally coordinated Li+ cations, an octahedral [Co(1,3-pdta)](2-) anion and five water molecules, two of which are uncoordinated, and is built of two-dimensional layers extending parallel to the (010) lattice plane, the constituents of which are connected by the coordinate bonds. O-H(water)...O hydrogen bonds operate both within and between these layers. The crystal investigated belongs to the enantiomeric space group P2(1) with only one (Lambda) of two possible optical isomers of the [Co(1,3-pdta)](2-) complex. A possible cause of enantiomer separation during crystallization might be the rigidification and polarization of the [M(1,3-pdta)](2-) core, resulting from direct coordination of Li+ cations to three out of four carboxylate groups constituting the 1,3-pdta ligand. The structure of (I) differs considerably from those of the other [M(II)(1,3-pdta)](2-) complexes, in which the charge compensation is realized by means of divalent hexaaqua complex cations. This finding demonstrates a significant structure-determining role of the counter-ions.

  4. Damage and deuterium retention in LiAlO 2 single crystals irradiated with deuterium ions using ion-beam techniques and optical absorption measurements

    Science.gov (United States)

    Katsui, H.; Nagata, S.; Tsuchiya, B.; Zhao, M.; Shikama, T.

    2011-10-01

    Ion beam analysis techniques and optical absorption measurements were employed to quantitatively examine the damage and deuterium retention in LiAlO 2 single crystals irradiated with 10 keV D2+. Rutherford backscattering spectrometry in channeling geometry revealed that the lattice atoms were disordered by the incident deuterium ions in the ratio O/Al of 2.5. Elastic recoil detection analysis showed that all the incident deuterium ions were retained near the end of their trajectories with a maximum concentration of 0.7 D/Al at room temperature. The depth profiles of the disordered atoms were nearly identical to those of the retained deuterium atoms. The release of the retained deuterium atoms and the annihilation of the ion-induced color centers, which contributed to an optical absorption band at 5.25 eV, were observed in the same temperature range. A correlation was established between the oxygen vacancies and the retained deuterium atoms.

  5. Neutralizing capacity of a new monovalent anti-Bothrops atrox antivenom: comparison with two commercial antivenoms

    Directory of Open Access Journals (Sweden)

    R. Otero

    1997-03-01

    Full Text Available Three horse-derived antivenoms were tested for their ability to neutralize lethal, hemorrhagic, edema-forming, defibrinating and myotoxic activities induced by the venom of Bothrops atrox from Antioquia and Chocó (Colombia. The following antivenoms were used: a polyvalent (crotaline antivenom produced by Instituto Clodomiro Picado (Costa Rica, b monovalent antibothropic antivenom produced by Instituto Nacional de Salud-INS (Bogotá, and c a new monovalent anti-B. atrox antivenom produced with the venom of B. atrox from Antioquia and Chocó. The three antivenoms neutralized all toxic activities tested albeit with different potencies. The new monovalent anti-B. atrox antivenom showed the highest neutralizing ability against edema-forming and defibrinating effects of B. atrox venom (41 ± 2 and 100 ± 32 µl antivenom/mg venom, respectively, suggesting that it should be useful in the treatment of B. atrox envenomation in Antioquia and Chocó

  6. Multivalent co-ions reduce DNA$-$DNA like-charge attraction and enhance DNA overcharging by mutivalent counterions

    CERN Document Server

    Duc, Nguyen Viet; Duc, Nguyen Huu

    2016-01-01

    Strongly correlated electrostatics of DNA systems has drawn the interest of many groups, especially the condensation and overcharging of DNA by multivalent counterions. By adding counterions of different valencies and shapes, one can enhance or reduce DNA overcharging. In this letter, we focus on the effect of multivalent co-ions, specifically divalent coion such as SO$_4^{2-}$, on the strongly correlated electrostatics of DNA condensation problem. A computational experiment of DNA condensation using Monte$-$Carlo simulation in grand canonical ensemble is carried out where DNA system is in equilibirium with a bulk solution containing a mixture of salt of different valency of co-ions. Compared to system with purely monovalent co-ions, the influence of divalent co-ions shows up in multiple aspects. Divalent co-ions lead to an increase of monovalent salt in the DNA condensate. Because monovalent salts mostly participate in linear screening of electrostatic interactions in the system, more monovalent salt molecul...

  7. Production and distribution of aberrations in resting or cycling human lymphocytes following Fe-ion or Cr-ion irradiation: Emphasis on single track effects

    Science.gov (United States)

    Deperas-Standylo, Joanna; Lee, Ryonfa; Nasonova, Elena; Ritter, Sylvia; Gudowska-Nowak, Ewa

    2012-09-01

    In the present study we examined the cytogenetic effects of 177 MeV/u Fe-ions (LET = 335 keV/μm) and 4.1 MeV/u Cr-ions (LET = 3160 keV/μm) in human lymphocytes under exposure conditions that result on average in one particle hit per cell nucleus. In non-cycling (G0-phase) lymphocytes the induction and the repair of excess fragments was measured by means of the premature chromosome condensation (PCC) technique and the distribution of breaks among cells was analysed. The PCC-data were further compared with those reported recently for stimulated lymphocytes at the first post-irradiation mitosis. Our experiments show that a single nuclear traversal by a Fe-ion produced more initial chromatin breakage than one Cr-ion, but after 24 h of repair the number of excess fragments/cell was similar for both ion species. All distributions of aberrations were overdispersed. For low energy Cr-ions, where the track radius is smaller than the radius of the cell nucleus, the data could be well described by a Neyman type A distribution. In contrast, the data obtained for high energy Fe-ions were fitted with a convoluted Poisson-Neyman distribution to account for the fact that the dose is deposited not only in the cell actually traversed but also in neighbouring cells. By applying metaphase analysis a different picture emerged with respect to the aberration yield, i.e. more aberrations were detected in cells exposed to Fe-ions than in those irradiated with Cr-ions. Yet, as observed for non-cycling lymphocytes all aberration distributions generated for metaphase cells were overdispersed. The obtained results are discussed with respect to differences in particle track structure. Additionally, the impact of confounding factors such as apoptosis that affect the number of aberrations expressed in a cell population is addressed.

  8. Medium-energy heavy-ion single-event-burnout imaging of power MOSFETs

    Energy Technology Data Exchange (ETDEWEB)

    Musseau, O.; Torres, A.; Campbell, A.B.; Knudson, A.R.; Buchner, S.; Fischer, B.; Schloegl, M.; Briand, P.

    1999-12-01

    The authors present the first experimental determination of the SEB sensitive area in a power MOSFET irradiated with a high-LET heavy-ion microbeam. They used a spectroscopy technique to perform coincident measurements of the charge collected in both source and drain junctions together, with a non-destructive technique (current limitation). The resulting charge collection images are related to the physical structure of the individual cells. These experimental data reveal the complex 3-dimensional behavior of a real structure, which can not easily be simulated using available tools. As the drain voltage is increased, the onset of burnout is reached, characterized by a sudden change in the charge collection image. Hot spots are observed where the collected charge reaches its maximum value. Those spots, due to burnout triggering events, correspond to areas where the silicon is degraded through thermal effects along a single ion track. This direct observation of SEB sensitive areas as applications for, either device hardening, by modifying doping profiles or layout of the cells, or for code calibration and device simulation.

  9. Failure mechanisms of single-crystal silicon electrodes in lithium-ion batteries

    Science.gov (United States)

    Shi, Feifei; Song, Zhichao; Ross, Philip N.; Somorjai, Gabor A.; Ritchie, Robert O.; Komvopoulos, Kyriakos

    2016-06-01

    Long-term durability is a major obstacle limiting the widespread use of lithium-ion batteries in heavy-duty applications and others demanding extended lifetime. As one of the root causes of the degradation of battery performance, the electrode failure mechanisms are still unknown. In this paper, we reveal the fundamental fracture mechanisms of single-crystal silicon electrodes over extended lithiation/delithiation cycles, using electrochemical testing, microstructure characterization, fracture mechanics and finite element analysis. Anisotropic lithium invasion causes crack initiation perpendicular to the electrode surface, followed by growth through the electrode thickness. The low fracture energy of the lithiated/unlithiated silicon interface provides a weak microstructural path for crack deflection, accounting for the crack patterns and delamination observed after repeated cycling. On the basis of this physical understanding, we demonstrate how electrolyte additives can heal electrode cracks and provide strategies to enhance the fracture resistance in future lithium-ion batteries from surface chemical, electrochemical and material science perspectives.

  10. Single- and double-ion type cross-linked polysiloxane solid electrolytes for lithium cells

    Science.gov (United States)

    Tsutsumi, Hiromori; Yamamoto, Masahiro; Morita, Masayuki; Matsuda, Yoshiharu; Nakamura, Takashi; Asai, Hiroyuki

    Polymeric solid electrolytes, that have poly(dimethylsiloxane) (PMS) backbone and cross-linked network, were applied to a rechargeable lithium battery system. Single- (PMS-Li) and double-ion type (PMS-LiClO 4) electrolytes were prepared from the same prepolymers. Lithium electrode in the both electrolytes showed reversible stripping and deposition of lithium. Intercalation and deintercalation processes of lithium ion between lithium-manganese composite oxide (Li xMnO 2) electrode and the electrolytes were also confirmed by cyclic voltammetry, however, peak current decreased with several cycles in both cases. The model cell, Li/PMS-Li/Li xMnO 2 cell had 1.4 mA h g -1 (per 1 g of active material, current density: 3.77 μA cm -2), and the Li/PMS-LiClO 4/Li xMnO 2 cell had 1.6 mA h g -1 (current density: 75.3 μA cm -2).

  11. Single- and double-ion type cross-linked polysiloxane solid electrolytes for lithium cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Hiromori; Yamamoto, Masahiro; Morita, Masayuki; Matsuda, Yoshiharu (Dept. of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Yamaguchi Univ., Ube (Japan)); Nakamura, Takashi; Asai, Hiroyuki (Dow Corning Toray Silicone Co. Ltd., Ichihara (Japan))

    1993-01-19

    Polymeric solid electrolytes, that have poly(dimethylsiloxane) (PMS) backbone and cross-linked network, were applied to a rechargeable lithium battery system. Single- (PMS-Li) and double-ion type (PMS-LiClO[sub 4]) electrolytes were prepared from the same prepolymers. Lithium electrode in the both electrolytes showed reversible stripping and deposition of lithium. Intercalation and deintercalation processes of lithium ion between lithium-manganese composite oxide (Li[sub x]MnO[sub 2]) electrode and the electrolytes were also confirmed by cyclic voltammetry, however, peak current decreased with several cycles in both cases. The model cell, Li/PMS-Li/Li[sub x]MnO[sub 2] cell had 1.4 mA h g[sup -1] (per 1 g of active material, current density: 3.77 [mu]A cm[sup -2]), and the Li/PMS-LiClO[sub 4]/Li[sub x]MnO[sub 2] cell had 1.6 mA h g[sup -1] (current density: 75.3 [mu]A cm[sup -2]). (orig.).

  12. Double-differential cross sections for single ionization of helium by bare ion impact

    Science.gov (United States)

    Jana, S.; Samanta, R.; Purkait, M.

    2013-11-01

    Double-differential cross sections (DDCS) for single ionization of helium by impact of proton and highly charged carbon ion have been calculated in the framework of four-body formalism using the three-Coulomb wave model (3C-4B) and first Born approximation (FBA-4B), respectively. The correlated motion of the particles interacting through long-range Coulomb potential is properly taken into account in the final state. In this paper, the energy and angular distributions of DDCS of low- and high-energy electron emission for ground-state helium atoms have been investigated. The ejected electrons are affected by the two-center field of the target and the projectile ion. The two-center effects are confined to comparison with other theoretical results. The results obtained, both from the 3C-4B and FBA-4B models, are compared with other theoretical and experimental findings. The present results are found to reproduce the peak structure of the experimental observations. Large discrepancy occurs between the present two theories at forward and backward angles except about the emission angle 90°. The present computed results obtained by the 3C-4B model are in good agreement with the available experimental findings.

  13. Mechanical response of UO{sub 2} single crystals submitted to low-energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tien-Hien [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud – CNRS/IN2P3, Université Paris-Saclay, Bâtiment 108, 91405 Orsay Cedex (France); Department of Physics, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Hanoi (Viet Nam); Debelle, Aurélien, E-mail: aurelien.debelle@u-psud.fr [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud – CNRS/IN2P3, Université Paris-Saclay, Bâtiment 108, 91405 Orsay Cedex (France); Boulle, Alexandre [Science des Procédés Céramiques et de Traitements de Surface CNRS UMR 7315, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges (France); Garrido, Frédérico; Thomé, Lionel [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud – CNRS/IN2P3, Université Paris-Saclay, Bâtiment 108, 91405 Orsay Cedex (France); Demange, Valérie [Institut des Sciences Chimiques de Rennes, CNRS UMR 6226, 263 avenue du Général Leclerc, Campus de Beaulieu – Bâtiment 10B, 35042 Rennes Cedex (France)

    2015-12-15

    {111}- and {100}-oriented UO{sub 2} single crystals were irradiated with 500-keV Ce{sup 3+} ions in the 10{sup 14}–9 × 10{sup 14} cm{sup −2} fluence range. The irradiation-induced strain was monitored using high-resolution X-ray diffraction. A mechanical modelling dedicated to thin irradiated layers was applied to account for the reaction of the unirradiated part of the crystals. The elastic strain, which is confined along the surface normal of the samples, increases with ion fluence until it is dramatically relieved. This behaviour is observed for both orientations. While the measured elastic strain depends on the crystallographic direction, the strain due to irradiation defects only is found to be equal for both directions, with a maximum value of ∼0.5%. Strain relaxation takes place at the damage peak, but the in-plane lattice parameter of the irradiated layer remains unchanged and equal to that of the pristine material. Meanwhile, the strain at the damaged/pristine interface continues to increase.

  14. Single-pulse and multipulse longitudinal phase space and temperature measurements of an intense ion beam

    Science.gov (United States)

    Coleman, J. E.; Seidl, P. A.; Bieniosek, F. M.; Leitner, M. A.; Lidia, S. M.; Vay, J. L.; Waldron, W. L.; Grote, D. P.; Welch, D. R.

    2012-07-01

    Longitudinal phase space and temperature measurements were conducted on a 2-3μs long, singly charged K+ ion bunch with an ion energy of ˜0.3MeV and current of 30 mA. The principal objective of these experiments was to measure the longitudinal beam dynamics and study the limits of axial compression. The differences between the measured beam energy, longitudinal beam dynamics, and the amplitude and time history of the Marx voltage waveform were all quantified. Longitudinal phase space measurements indicate a slight chromaticity (<1%) in the beam from head to tail. Record low longitudinal temperatures of Tz=2-4×10-2eV were measured for a beam bunch of this intensity with negligible effects from neutralizing the beam space charge with a background plasma. A qualitative comparison of experimental and calculated results are presented, which include time resolved longitudinal distributions, and phase space of the beam at 430 cm.

  15. Dynamic memory of a single voltage-gated potassium ion channel: A stochastic nonequilibrium thermodynamic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Kinshuk, E-mail: kbpchem@gmail.com [Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Kolkata 700 009 (India)

    2015-05-14

    In this work, we have studied the stochastic response of a single voltage-gated potassium ion channel to a periodic external voltage that keeps the system out-of-equilibrium. The system exhibits memory, resulting from time-dependent driving, that is reflected in terms of dynamic hysteresis in the current-voltage characteristics. The hysteresis loop area has a maximum at some intermediate voltage frequency and disappears in the limits of low and high frequencies. However, the (average) dissipation at long-time limit increases and finally goes to saturation with rising frequency. This raises the question: how diminishing hysteresis can be associated with growing dissipation? To answer this, we have studied the nonequilibrium thermodynamics of the system and analyzed different thermodynamic functions which also exhibit hysteresis. Interestingly, by applying a temporal symmetry analysis in the high-frequency limit, we have analytically shown that hysteresis in some of the periodic responses of the system does not vanish. On the contrary, the rates of free energy and internal energy change of the system as well as the rate of dissipative work done on the system show growing hysteresis with frequency. Hence, although the current-voltage hysteresis disappears in the high-frequency limit, the memory of the ion channel is manifested through its specific nonequilibrium thermodynamic responses.

  16. The effect of CuII ions in L-asparagine single crystals

    Science.gov (United States)

    Santana, Ricardo C.; Gontijo, Henrique O.; Menezes, Arthur F.; Martins, José A.; Carvalho, Jesiel F.

    2016-11-01

    We report the synthesis, crystal growth, and spectroscopic characterization of L-asparagine monohydrate (LAM) single crystals doped with CuII. The crystals were successfully grown by slow cooling from a supersaturated aqueous solution up to size of 16×12×2 mm3;the effect of copper impurities in the crystals morphology was discussed. Electron Paramagnetic Resonance (EPR) was used to calculate the g and hyperfine coupling (A) tensors of the CuII ions (g1=2.044, g2=2.105, g3=2.383and A1≈0, A2=35, A3=108 Gauss). The EPR spectra for certain orientations of the magnetic field suggest that CuII ions are coordinated to two 14N atoms. Correlating the EPR and optical absorption results, the crystal field and the CuII orbital bond parameters were calculated. The results indicate that the paramagnetic center occupies interstitial rhombic distorted site and the ground orbital state for the unpaired electron is the d(x2-y2).

  17. Gain properties of germanate glasses singly doped with Tm3+ and Ho3+ ions

    Institute of Scientific and Technical Information of China (English)

    LIN Qiongfei; XIA Haiping; ZHANG Yuepin; WANG Jinhao; ZHANG Jianli; HE Sailong

    2009-01-01

    Two kinds of germanate glasses singly doped with the ion concentration of 2.0mol.%Tm3+ and 2.0mol.%Ho3+, respectively, were prepared. According to McCumber theory, the absorption and stimulated emission cross-sections corresponding to the 3H6←→3F4 transitions of Tm3+ (at 1.8 μm) and the 5I8←→5I7 transitions of Ho3+ (at 2.0 μm) were obtained, and respective gain cross-section spectra were also computed as a function of population inversion according to absorption and emission cross-sections and the ion concentrations. For Tm3+-doped germanate glasses, the maximum of the absorption, emission, and gain cross-sections reached a value higher than those reported for fluorozirconate, fluoride, and oxyfluoride glasses. For Ho3+-doped germanate glasses, the maximum of absorption, emission, and gain cross-sections reached a value higher than that reported for fluorozircoaluminate glasses. Hence, these Tm3+-doped and Ho3+-doped germanate glasses exhibited an advantage for application in mid-infrared lasers at about 1.8 and 2.0 μm wavelength.

  18. Luminescent single-ion magnets from Lanthanoid(III) complexes with monodentate ketone ligands

    Energy Technology Data Exchange (ETDEWEB)

    Kanetomo, Takuya; Ishida, Takayuki, E-mail: takayuki.ishida@uec.ac.jp [Department of Engineering Science, The University of Electro-Communications, Tokyo (Japan)

    2016-02-01

    We synthesized [Ln{sup III}(hfac){sub 3}(H{sub 2}O)(L)] (abbreviated as Ln-L; Ln = Gd, Tb, Eu; L = DTBK (di-t-butyl ketone), BP (benzophenone)), in which the carbonyl oxygen atom was coordinated to the Ln ion center, despite of such bulky substituents. Their crystal structures were determined by means of X-ray diffraction study. Gd-DTBK is completely isomorphous to the di-t-butyl nitroxide derivative and accordingly can be regarded as a model with the ligand spin masked. The ac magnetic susceptibility measurements on Tb-DTBK and -BP showed frequency dependence, characteristic of single-ion magnets. They also displayed photoluminescence in the solid state at room temperature. The quantum yields of the luminescence of Tb-DTBK and -BP (λ{sub ex} = 360 nm) were improved to 57 and 35%, respectively, from that of the starting material [TbI{sup III}(hfac){sub 3}(H{sub 2}O){sub 2}] (28% at λ{sub ex} = 370 nm). Similarly, the quantum yields for Eu-DTBK and -BP were 8 and 15%, respectively, with λ{sub ex} = 400 nm, while that of the starting material [EuI{sup III}(hfac){sub 3}(H{sub 2}O){sub 2}] was 4% at λ{sub ex}=400 nm.

  19. Real-time single-ion hit position detecting system for cell irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Takahiro, E-mail: satoh.takahiro37@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Koka, Masahi [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Kada, Wataru [Faculty of Science and Technology, Gunma University, 1-5-1 Tenjin-machi, Kiryu, Gunma 376-8515 (Japan); Yokoyama, Akihito; Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2014-08-01

    We have developed a real-time single-ion hit position detecting system to replace a CR-39 solid-state nuclear-track detector for cell irradiation experiments because the CR-39 takes several minutes for off-line etching. The new real-time system consists of a 500-μm-thick CaF{sub 2}(Eu) scintillator, an optical microscope with a 10× objective lens, and a high-gain charge-coupled device camera. Each of the 260-MeV neon ions passing through a 100-μm-thick CR-39 sheet was detected using the real-time system in a performance test for the spatial resolution. The full width at half maxima (FWHMs) of the distances between positions detected by the real-time system and the centers of the etch pits on CR-39 were 6.5 and 6.9 μm in the x and y directions, respectively. The result shows that the system is useful for typical cultured cells of a few tens of micrometers in size.

  20. Applications of SU-8 in the development of a Single Ion Hit Facility

    Energy Technology Data Exchange (ETDEWEB)

    Arteaga-Marrero, N. [Division of Nuclear Physics, Department of Physics, Lund University, Professorsgatan 1, Box 118, SE-22100 Lund (Sweden)], E-mail: natalia.arteaga@nuclear.lu.se; Astromskas, G. [Division of Solid State Physics, Department of Physics, Lund University, Professorsgatan 1, Box 118, SE-22100 Lund (Sweden); Olsson, M.G. [Department of Infection Medicine, Lund University, Soelvegatan 19, B14, SE-22184 Lund (Sweden); Elfman, M.; Kristiansson, P.; Nilsson, E.J.C.; Nilsson, C.; Pallon, J. [Division of Nuclear Physics, Department of Physics, Lund University, Professorsgatan 1, Box 118, SE-22100 Lund (Sweden)

    2009-06-15

    The Lund Nuclear Microprobe (LNM) has been adapted to be used as a Single Ion Hit Facility (SIHF) for proton cell irradiation experiments at low dose. In order to test the capabilities of the system, Ni dot arrays and artificial cells have been fabricated with the photopolymer SU-8 and common lithographic techniques. The primary purpose of the Ni dot arrays was to determine the targeting accuracy of the beam in vacuum and in air. Additionally, this sample was employed to evaluate the system performance during cell target irradiation experiments. The Ni dot arrays were also used for beam characterization. The artificial cells were originally fabricated to test the software for cell recognition and localization, developed and implemented at the LNM. However, this sample became very functional to make small adjustments at the irradiation chamber for cell irradiation experiments. A description of the samples, fabrication procedure and applications are presented in this paper.

  1. Optimal joint measurements of complementary observables by a single trapped ion

    Science.gov (United States)

    Xiong, T. P.; Yan, L. L.; Ma, Z. H.; Zhou, F.; Chen, L.; Yang, W. L.; Feng, M.; Busch, P.

    2017-06-01

    The uncertainty relations, pioneered by Werner Heisenberg nearly 90 years ago, set a fundamental limitation on the joint measurability of complementary observables. This limitation has long been a subject of debate, which has been reignited recently due to new proposed forms of measurement uncertainty relations. The present work is associated with a new error trade-off relation for compatible observables approximating two incompatible observables, in keeping with the spirit of Heisenberg’s original ideas of 1927. We report the first direct test and confirmation of the tight bounds prescribed by such an error trade-off relation, based on an experimental realisation of optimal joint measurements of complementary observables using a single ultracold {}40{{{Ca}}}+ ion trapped in a harmonic potential. Our work provides a prototypical determination of ultimate joint measurement error bounds with potential applications in quantum information science for high-precision measurement and information security.

  2. Single-Ion Microbeam for Applications in Radiobiology: State of the Art

    Institute of Scientific and Technical Information of China (English)

    Hu Zhiwen; Wu Lijun; Yu Zengliang

    2005-01-01

    Single-Ion Microbeam (SIM) is uniquely capable of precisely delivering a predefined number of charged particles (precise doses of radiation) to individual cells or sub-cellular targets in situ. Since the early 1990's, there has been an ever-increasing interest in developing and applying the SIM technique to problems in radiobiology for studies of cell and tissue damaged by ionizing radiations. Potential applications for SIM in radiobiology continues to grow and have been diversified. There are currently more than 14 SIM facilities worldwide, and they have been in a constant state of evolution. This paper reviews the current state of SIM research worldwide and the related pivotal technological developments in the fields of both biophysics and radiobiology.Representative applications and the perspective of SIM are also introduced and discussed.

  3. Fully differential cross sections for the single ionization of He by C{sup 6+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, J [Theoretical Division, Los Alamos National Laboratory, NM 87545 (United States); Pindzola, M S; Robicheaux, F [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Ciappina, M F [ICFO-Institut de Ciences Fotoniques, 08860 Castelldefels (Barcelona) (Spain)

    2011-09-14

    We present fully differential cross sections for the single ionization of He by C{sup 6+} ions. A time-dependent close-coupling approach is used to describe the two-electron wavefunction in the field of the projectile for a range of impact parameters, and a Fourier transform approach is used to extract fully differential cross sections for a specific momentum transfer. Our calculations are compared to the measurements of Schulz et al (2003 Nature 422 48) and we find very good agreement in the scattering plane and good qualitative agreement in the perpendicular plane. In particular, our calculations in the perpendicular plane find a similar 'double-peak' structure in the angular distributions to those seen experimentally. We also discuss the various checks made on our calculations by comparing to a one-electron time-dependent calculation.

  4. Single ionization of helium atoms by energetic fully stripped carbon ions

    Institute of Scientific and Technical Information of China (English)

    Ebrahim Ghanbari-Adivi; Sadjad Eskandari

    2015-01-01

    A four-body distorted wave approximation is presented for theoretical investigations of the single ionization of ground-state helium atoms by fully stripped carbon ions at impact energies of 2 MeV/amu and 100 MeV/amu. The nine-dimensional integrals for the partial quantum-mechanical transition amplitudes of the specified reaction are reduced to some analytical expressions or one-dimensional integrals over real variables. Fully differential cross sections (FDCSs) are calculated and compared with their experimental values as well as the results obtained from other theories. Despite the simplicity and quickness of the proposed quadrature, the comparison shows that the obtained results are in reasonable agreement with the experiment and are compatible with those of other complicated theories.

  5. Compliant glass-polymer hybrid single ion-conducting electrolytes for lithium batteries.

    Science.gov (United States)

    Villaluenga, Irune; Wujcik, Kevin H; Tong, Wei; Devaux, Didier; Wong, Dominica H C; DeSimone, Joseph M; Balsara, Nitash P

    2016-01-05

    Despite high ionic conductivities, current inorganic solid electrolytes cannot be used in lithium batteries because of a lack of compliance and adhesion to active particles in battery electrodes as they are discharged and charged. We have successfully developed a compliant, nonflammable, hybrid single ion-conducting electrolyte comprising inorganic sulfide glass particles covalently bonded to a perfluoropolyether polymer. The hybrid with 23 wt% perfluoropolyether exhibits low shear modulus relative to neat glass electrolytes, ionic conductivity of 10(-4) S/cm at room temperature, a cation transference number close to unity, and an electrochemical stability window up to 5 V relative to Li(+)/Li. X-ray absorption spectroscopy indicates that the hybrid electrolyte limits lithium polysulfide dissolution and is, thus, ideally suited for Li-S cells. Our work opens a previously unidentified route for developing compliant solid electrolytes that will address the challenges of lithium batteries.

  6. Alternative Single-Solvent Electrolytes Based on Cyanoesters for Safer Lithium-Ion Batteries.

    Science.gov (United States)

    Brox, Sebastian; Röser, Stephan; Husch, Tamara; Hildebrand, Stephan; Fromm, Olga; Korth, Martin; Winter, Martin; Cekic-Laskovic, Isidora

    2016-07-07

    To identify alternative single-solvent-based electrolytes for application in lithium-ion batteries (LIBs), adequate computational methods were applied to screen specified physicochemical and electrochemical properties of new cyanoester-based compounds. Out of 2747 possible target compounds, two promising candidates and two structurally equivalent components were chosen. A constructive selection process including evaluation of basic physicochemical properties as well assessing the compatibility towards graphitic anodes was initiated to identify the most promising candidates. With addition of a film-forming additive in a low concentration, the most promising candidate showed an adequate long-term cycling stability with LiNi1/3 Mn1/3 Co1/3 O2 [NMC(111)] in a full-cell setup using graphite as anode material. The main advantages of the new electrolyte formulation are related to its good thermal behavior, especially with regard to safety in combination with satisfying electrochemical performance.

  7. High rate lithium-sulfur battery enabled by sandwiched single ion conducting polymer electrolyte

    Science.gov (United States)

    Sun, Yubao; Li, Gai; Lai, Yuanchu; Zeng, Danli; Cheng, Hansong

    2016-02-01

    Lithium-sulfur batteries are highly promising for electric energy storage with high energy density, abundant resources and low cost. However, the battery technologies have often suffered from a short cycle life and poor rate stability arising from the well-known “polysulfide shuttle” effect. Here, we report a novel cell design by sandwiching a sp3 boron based single ion conducting polymer electrolyte film between two carbon films to fabricate a composite separator for lithium-sulfur batteries. The dense negative charges uniformly distributed in the electrolyte membrane inherently prohibit transport of polysulfide anions formed in the cathode inside the polymer matrix and effectively blocks polysulfide shuttling. A battery assembled with the composite separator exhibits a remarkably long cycle life at high charge/discharge rates.

  8. A single lithium-ion battery protection circuit with high reliability and low power consumption

    Institute of Scientific and Technical Information of China (English)

    Jiang Jinguang; Li Sen

    2014-01-01

    A single lithium-ion battery protection circuit with high reliability and low power consumption is proposed.The protection circuit has high reliability because the voltage and current of the battery are controlled in a safe range.The protection circuit can immediately activate a protective function when the voltage and current of the battery are beyond the safe range.In order to reduce the circuit's power consumption,a sleep state control circuit is developed.Additionally,the output frequency of the ring oscillation can be adjusted continuously and precisely by the charging capacitors and the constant-current source.The proposed protection circuit is fabricated in a 0.5 μm mixed-signal CMOS process.The measured reference voltage is 1.19 V,the overvoltage is 4.2 V and the undervoltage is 2.2 V.The total power is about 9μW.

  9. Single electrons from heavy-flavor mesons in relativistic heavy-ion collisions

    Science.gov (United States)

    Song, Taesoo; Berrehrah, Hamza; Torres-Rincon, Juan M.; Tolos, Laura; Cabrera, Daniel; Cassing, Wolfgang; Bratkovskaya, Elena

    2017-07-01

    We study the single electron spectra from D - and B - meson semileptonic decays in Au+Au collisions at √{sNN}=200 , 62.4, and 19.2 GeV by employing the parton-hadron-string dynamics (PHSD) transport approach that has been shown to reasonably describe the charm dynamics at Relativistic Heavy Ion Collider and Large Hadron Collider energies on a microscopic level. In this approach the initial charm and bottom quarks are produced by using the PYTHIA event generator which is tuned to reproduce the fixed-order next-to-leading logarithm calculations for charm and bottom production. The produced charm and bottom quarks interact with off-shell (massive) partons in the quark-gluon plasma with scattering cross sections which are calculated in the dynamical quasiparticle model that is matched to reproduce the equation of state of the partonic system above the deconfinement temperature Tc. At energy densities close to the critical energy density (≈0.5 GeV /fm3 ) the charm and bottom quarks are hadronized into D and B mesons through either coalescence or fragmentation. After hadronization the D and B mesons interact with the light hadrons by employing the scattering cross sections from an effective Lagrangian. The final D and B mesons then produce single electrons through semileptonic decay. We find that the PHSD approach well describes the nuclear modification factor RAA and elliptic flow v2 of single electrons in d +Au and Au+Au collisions at √{sNN}=200 GeV and the elliptic flow in Au+Au reactions at √{sNN}=62.4 GeV from the PHENIX Collaboration, however, the large RAA at √{sNN}=62.4 GeV is not described at all. Furthermore, we make predictions for the RAA of D mesons and of single electrons at the lower energy of √{sNN}=19.2 GeV . Additionally, the medium modification of the azimuthal angle ϕ between a heavy quark and a heavy antiquark is studied. We find that the transverse flow enhances the azimuthal angular distributions close to ϕ =0 because the heavy

  10. Transport of ions and biomolecules through single asymmetric nanopores in polymer films

    Science.gov (United States)

    Schiedt, Birgitta; Healy, Ken; Morrison, Alan P.; Neumann, Reinhard; Siwy, Zuzanna

    2005-07-01

    Single conical nanopores in polymer foils show 'rectifying' diode-like current-voltage (I-V) characteristics, with preferential cation flow in the direction from the narrow to the wide opening [P. Apel, Y.E. Korchev, Z. Siwy, R. Spohr, M. Yoshida, Nucl. Instr. and Meth. B 184 (2001) 337-346, Z. Siwy, D. Dobrev, R. Neumann, C. Trautmann, K. Voss, Appl. Phys. A 76 (2003) 781-785]. To produce single-pore membranes, we irradiated polymer films (polyethylene terephthalate and polyimide) with single heavy ions (using kinetic energies in the GeV range) and subsequently performed asymmetric chemical track-etching. The resulting conical pores had narrow openings of 4-20 nm. The I-V curves of these pores were measured in aqueous KCl solutions of various concentrations and pH values, and it was found that both parameters influence the rectification properties of the pores. For decreasing concentrations, down to 0.1 M, the degree of rectification increases, as predicted by a recently proposed model [Z. Siwy, A. Fulinski, Phys. Rev. Lett. 89 (2002) 198103], however, as the concentration decreases further, the rectification unexpectedly begins to decrease again. We suspect that this is due to conformation changes occurring in the pore. Also, our results have shown that the pores exhibit a non-classical conductance versus electrolyte concentration characteristic, having elevated conductances at low concentrations, for which we propose an explanation based on surface conductivity. Finally, we present an application of the polyimide conical nanopores as single-molecule DNA sensors, with results demonstrating their ability to detect individual plasmid DNA molecules.

  11. Matrix-assisted laser desorption/ionization mass spectrometry method for selectively producing either singly or multiply charged molecular ions.

    Science.gov (United States)

    Trimpin, Sarah; Inutan, Ellen D; Herath, Thushani N; McEwen, Charles N

    2010-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is noted for its ability to produce primarily singly charged ions. This is an attribute when using direct ionization for complex mixtures such as protein digests or synthetic polymers. However, the ability to produce multiply charged ions, as with electrospray ionization (ESI), has advantages such as extending the mass range on mass spectrometers with limited mass-to-charge (m/z) range and enhancing fragmentation for structural characterization. We designed and fabricated a novel field free transmission geometry atmopsheric pressure (AP) MALDI source mounted to a high-mass resolution Orbitrap Exactive mass spectrometer. We report the ability to produce at will either singly charged ions or highly charged ions using a MALDI process by simply changing the matrix or the matrix preparation conditions. Mass spectra with multiply charged ions very similar to those obtained with ESI of proteins such as cytochrome c and ubiquitin are obtained with low femtomole amounts applied to the MALDI target plate and for peptides such as angiotensin I and II with application of attomole amounts. Single scan acquisitions produce sufficient ion current even from proteins.

  12. Reentrant phenomena in a three-dimensional spin-1 planar ferromagnet with easy-axis single-ion anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Mercaldo, M.T., E-mail: mtm@physics.unisa.it [Dipartimento di Fisica “E. R. Caianiello”, Università di Salerno and CNISM, Unità di Salerno, I-84084 Fisciano, Salerno (Italy); Rabuffo, I.; De Cesare, L. [Dipartimento di Fisica “E. R. Caianiello”, Università di Salerno and CNISM, Unità di Salerno, I-84084 Fisciano, Salerno (Italy); Caramico D' Auria, A. [Dipartimento di Fisica, Università di Napoli Federico II, I-80125 Napoli (Italy)

    2014-09-01

    The two-time Green function method is employed to explore the phase diagram and the magnetic-field-induced quantum criticality of a three-dimensional spin-one planar ferromagnet with easy-axis single-ion anisotropy. We adopt the Tyablikov and Anderson-Callen decouplings for higher order exchange and single-ion anisotropy Green functions, respectively. The central finding is that, within a characteristic range of the anisotropy parameter values, reentrant phenomena occur in the phase diagram close to the quantum critical point producing a sensible change of the conventional quantum critical scenario. - Highlights: • We study he effects of single-ion anisotropy on the magnetic-field-induced quantum criticality. • The method used is the two-time Green's function framework. • We find that the structure of the phase diagram is modified. • Reentrant critical lines appear in a given range of the anisotropy parameter values.

  13. Optimization of large area YBa 2Cu 3O 7-x films by single target ion beam sputtering

    Science.gov (United States)

    Gauzzi, A.; Lucia, M. L.; Affronte, M.; Pavuna, D.

    1991-12-01

    We report on the in-situ growth over large area of high-quality homogeneous YBa 2Cu 3O 7-x films by single target ion beam sputtering. The ‘123’ stoichiometry transfer to the substrates is obtained by using sufficiently low power ion beam and a grazing angle between the ion beam and the target. The as-deposited films show consistent homogeneity and reproducible superconducting properties (ΔT c10 6 A cm -2 at 77 K) over areas larger than ≈30 cm 2.

  14. Comb-shaped single ion conductors based on polyacrylate ethers and lithium alkyl sulfonate

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xiaoguang [Lawrence Berkeley National Laboratory, EETD, MS 62-203, One Cyclotron Road, Berkeley, CA 94720 (United States)]. E-mail: xsun@lbl.gov; Hou Jun [Lawrence Berkeley National Laboratory, EETD, MS 62-203, One Cyclotron Road, Berkeley, CA 94720 (United States); Kerr, John B. [Lawrence Berkeley National Laboratory, EETD, MS 62-203, One Cyclotron Road, Berkeley, CA 94720 (United States)]. E-mail: jbkerr@lbl.gov

    2005-01-15

    Comb-shaped single ion conductors have been synthesized by (1) sulfonation of small molecule chloroethyleneglycols, which, after ion exchange to the Li{sup +} salt were then converted to the acrylate by reaction with acryloyl chloride and copolymerized with polyethylene glycol monomethyl ether acrylate (Mn = 454, n = 8) (PAE{sub 8}-co-E{sub 3}SO{sub 3}Li); (2) sulfonation of chloride end groups grafted on to prepolymers of polyacrylate ethers (PAE{sub 8}-g-E{sub n}SO{sub 3}Li, n = 2, 3). The highest conductivity at 25 deg. C of 2.0 x 10{sup -7} S cm{sup -1} was obtained for the PAE{sub 8}-co-E{sub 3}SO{sub 3}Li with a salt concentration of EO/Li = 40. The conductivity of PAE{sub 8}-g-E{sub 3}SO{sub 3}Li is lower than that of PAE{sub 8}-co-E{sub 3}SO{sub 3}Li at similar salt concentrations, which is related to the incomplete sulfonation of the grafted polymer that leads to a lower concentration of Li{sup +}. The addition of 50 wt.% of plasticizer, PC/EMC (1/1, v/v), to PAE{sub 8}-g-E{sub 2}SO{sub 3}Li increases the ambient conductivity by three orders of magnitude, which is due to the increased ion mobility in a micro-liquid environment and an increase concentration of free ions as a result of the higher dielectric constant of the solvent. A symmetrical Li/Li cell with an electrolyte membrane consisting of 75 wt.% PC/EMC (1/1, v/v) was cycled at a current density of 100 {mu}A cm{sup -2} at 85 deg. C. The cycling profile showed no concentration polarization after a break-in period during the first few cycles, which was apparently due to reaction of the solvent at the lithium metal surface that reacted with lithium metal to form a stable SEI layer.

  15. Comb-shaped single ion conductors based on polyacrylate ethers and lithium alkyl sulfonate

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Guang Sun; Jan Hou; Kerr, J.B. [Lawrence Berkeley National Lab., CA (United States). EETD

    2005-01-15

    Comb-shaped single ion conductors have been synthesized by (1) sulfonation of small molecule chloroethyleneglycols, which, after ion exchange to the Li{sup +} salt were then converted to the acrylate by reaction with acryloyl chloride and copolymerized with polyethylene glycol monomethyl ether acrylate (Mn = 454, n = 8) (PAE{sub 8}-co-E{sub 3}SO{sub 3}Li); (2) sulfonation of chloride end groups grafted on to prepolymers of polyacrylate ethers (PAE{sub 8}-g-E{sub n}SO{sub 3}Li, n = 2, 3). The highest conductivity at 25 {sup o}C of 2.0 x {sup -7} S cm{sup -1} was obtained for the PAE{sub 8}-co-E{sub 3}SO{sub 3}Li with a salt concentration of EO/Li = 40. The conductivity of PAE{sub 8}-g-E{sub 3}SO{sub 3}Li is lower than that of PAE{sub 8}-co-E{sub 3}SO{sub 3}Li at similar salt concentrations, which is related to the incomplete sulfonation of the grafted polymer that leads to a lower concentration of Li{sup +}. The addition of 50 wt.% of plasticizer, PC/EMC (1/1, v/v), to PAE{sub 8}-g-E{sub 2}SO{sub 3}Li increases the ambient conductivity by three orders of magnitude, which is due to the increased ion mobility in a micro-liquid environment and an increase concentration of free ions as a result of the higher dielectric constant of the solvent. A symmetrical Li/Li cell with an electrolyte membrane consisting of 75 wt.% PC/EMC (1/1, v/v) was cycled at a current density of 100 {mu}A cm{sup -2} at 85 {sup o}C. The cycling profile showed no concentration polarization after a break-in period during the first few cycles, which was apparently due to reaction of the solvent at the lithium metal surface that reacted with lithium metal to form a stable SEI layer. (Author)

  16. Magnetic anisotropy and mechanism of magnetic relaxation in Er(III) single-ion magnets.

    Science.gov (United States)

    Singh, Saurabh Kumar; Gupta, Tulika; Rajaraman, Gopalan

    2014-10-20

    Magnetic anisotropy is a key component in the design of single-molecule magnets (SMMs) possessing a large barrier height for magnetization reversal. Lanthanide-based SMMs are the most promising candidates in this arena as they offer a large magnetic anisotropy due to the presence of strong spin-orbit coupling. Among lanthanides, Er(III) complexes are gaining attention in the area of SMMs, because of their intriguing magnetic properties and attractive blocking temperatures. Here, we have undertaken detailed ab initio calculations on four structurally diverse Er(III) SMMs to shed light on how the magnetic anisotropy is influenced by the role of symmetry and structural distortions. The employed CASSCF+RASSI calculations have offered rationale for the observed differences in the estimated Ueff values for the studied complexes and also offered hints to the mechanism of magnetic relaxation. The differences in the mechanism of magnetic relaxations are further analyzed based on the Er-ligand interactions, which is obtained by analyzing the charges, densities, luminescent behavior and the frontier molecular orbitals. Our calculations, for the first time, have highlighted the importance of high symmetry environment and ligand donor strength in obtaining large Ueff values for the Er(III) complexes. We have examined these possibilities by modeling several structures with variable coordination numbers and point group symmetry. These results signify the need of a detailed understanding on the shape of the anisotropy and the point group symmetry in order to achieve large Ueff values in Er(III) single-ion magnets.

  17. Performance of single chamber biocatalyzed electrolysis with different types of ion exchange membranes.

    Science.gov (United States)

    Rozendal, René A; Hamelers, Hubertus V M; Molenkamp, Redmar J; Buisman, Cees J N

    2007-05-01

    In this paper hydrogen production through biocatalyzed electrolysis was studied for the first time in a single chamber configuration. Single chamber biocatalyzed electrolysis was tested in two configurations: (i) with a cation exchange membrane (CEM) and (ii) with an anion exchange membrane (AEM). Both configurations performed comparably and produced over 0.3 m3 H2/m3 reactor liquid volume/day at 1.0 V applied voltage (overall hydrogen efficiencies around 23%). Analysis of the water that permeated through the membrane revealed that a large part of potential losses in the system were associated with a pH gradient across the membrane (CEM DeltapH=6.4; AEM DeltapH=4.4). These pH gradient associated potential losses were lower in the AEM configuration (CEM 0.38 V; AEM 0.26 V) as a result of its alternative ion transport properties. This benefit of the AEM, however, was counteracted by the higher cathode overpotentials occurring in the AEM configuration (CEM 0.12 V at 2.39 A/m2; AEM 0.27 V at 2.15 A/m2) as a result of a less effective electroless plating method for the AEM membrane electrode assembly (MEA).

  18. Partition Equilibrium Between Charged Membrane and Single Electrolyte Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    徐铜文; 杨伟华; 何柄林

    2001-01-01

    Ionic partition equilibrium in charged membrane immersed in solution of single electrolyte with monovalence or multi-valence is systematically investigated and several expressions are established for determination of partition coefficients. On this basis, the effects of the ratio of membrane charge density to hulk electrolyte solution concentration, the charge sign and valence of electrolyte ions and the type of membrane on the partition equilibrium were analyzed and simulated with in chosen parameters. It is revealed that ion partition is not related solely withthe respective concentrations but also definitely with the concentration ratio of fixed group to bulk solution in addition to the charge sign and the valence. For a counterion, the partition coefficient increases with this ratio and the valence; while for a coion, the partition coefficient decreases with this ratio and the valence. The theoreticalcal culations were compared with the experimental data and a good agreement was observed.

  19. Investigation of focused ion beam induced damage in single crystal diamond tools

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Zhen [Centre for Precision Manufacturing, Department of Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XQ (United Kingdom); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Luo, Xichun, E-mail: Xichun.Luo@strath.ac.uk [Centre for Precision Manufacturing, Department of Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XQ (United Kingdom)

    2015-08-30

    Highlights: • The FIB-induced damage layer should be paid enough attention when shaping the cutting edges of nanoscale diamond tools. • During FIB processing cutting tools made of natural single crystal diamond, the Ga{sup +} collision will create a damage layer around tool tips. • The thicknesses of damaged layer and the level for amorphization of diamond significantly increase with beam energy. • The FIB-induced doping and defects during tool fabrication are responsible for the early detection of tool wear of nanoscale diamond tools. - Abstract: In this work, transmission electron microscope (TEM) measurements and molecular dynamics (MD) simulations were carried out to characterise the focused ion beam (FIB) induced damage layer in a single crystal diamond tool under different FIB processing voltages. The results obtained from the experiments and the simulations are in good agreement. The results indicate that during FIB processing cutting tools made of natural single crystal diamond, the energetic Ga{sup +} collision will create an impulse-dependent damage layer at the irradiated surface. For the tested beam voltages in a typical FIB system (from 8 kV to 30 kV), the thicknesses of the damaged layers formed on a diamond tool surface increased from 11.5 nm to 27.6 nm. The dynamic damage process of FIB irradiation and ion–solid interactions physics leading to processing defects in FIB milling were emulated by MD simulations. The research findings from this study provide the in-depth understanding of the wear of nanoscale multi-tip diamond tools considering the FIB irradiation induced doping and defects during the tool fabrication process.

  20. Monovalent RIVM meningococcal B OMP vesicle F91 vaccines in toddlers

    NARCIS (Netherlands)

    Lafeber AB; Limpt CJP van; Labadie J; Berbers GAM; Kleijn ED de; Groot R de; Rumke HC; Alphen AJW; Sophia Kinderziekenhuis /; LVO

    2001-01-01

    This report gives the results of a randomised phase-II clinical study into the safety and immunogenicity of a monovalent MenB OMV vaccine expressing P1.7h,4 PorA (MonoMen) in toddlers. Safety and immunogenicity are compared for two types of vaccine that are differently adjuvated (either aluminium ph

  1. Structural and optical properties of Cd{sup 2+} ion on the growth of sulphamic acid single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Rajyalakshmi, S.; Samatha, K. [Department of Physics, Andhra University, Visakhapatnam-530003 (India); Rao, Valluru Srinivasa; Reddy, P. V. S. S. S. N.; Rao, K. Ramachandra, E-mail: drkrcr@gmail.com [Crystal Growth & Nano Science Research Center, Department of Physics, Govt. College (A), Rajahmundry-533 105 (India); Krishna, V. Y. Rama [Department of Engg. Physics, Andhra University, Visakhapatnam-530003 (India)

    2016-05-06

    Transparent single crystals of Cadmium doped Sulphamic acid (SA) was grown by Conventional slow evaporation solution technique (SEST) which had the size of 13 × 8 × 7 mm{sup 3}. The grown single crystals have been characterized using single crystal X-ray diffraction UV-visible Spectral studies and Second harmonic generation (SHG) efficiency and the results were discussed. The lattice parameters of the grown Cd{sup 2+} ion doped SA crystal are confirmed by single crystal X-ray diffraction and belong to orthorhombic system. Optical transmittance of the crystal was recorded using UV-vis NIR spectrophotometer with its lower cut off wavelength around 259nm. SHG measurements indicate that the SHG efficiency of the grown Cd{sup 2+} ion doped SA crystal at a fundamental wavelength of 1064 nm is approximately equal to KDP.

  2. Correlation of precursor and product ions in single-stage high resolution mass spectrometry. A tool for detecting diagnostic ions and improving the precursor elemental composition elucidation

    Energy Technology Data Exchange (ETDEWEB)

    Borràs, S. [Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain); Kaufmann, A., E-mail: anton.kaufmann@klzh.ch [Official Food Control Authority, Fehrenstrasse 15, 8032 Zürich (Switzerland); Companyó, R. [Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain)

    2013-04-15

    Highlights: ► We are describing a technique to spot ions which are derived from each other. ► Single stage high resolution data is used. ► This “in silicon” technique is compared to conventional precursor scan. ► Some applications for this technique are presented. -- Abstract: Monitoring of common diagnostic fragments is essential for recognizing molecules which are members of a particular compound class. Up to now, unit resolving tandem quadrupole mass spectrometers, operating in the precursor ion scan mode, have been typically used to perform such analysis. By means of high-resolution mass spectrometry (HRMS) a much more sensitive and selective detection can be achieved. However, using a single-stage HRMS instrument, there is no unequivocal link to the corresponding precursor ion, since such instrumentation does not permit a previous precursor selection. Thus, to address this limitation, an in silico approach to locate precursor ions, based on diagnostic fragments, was developed. Implemented as an Excel macro, the algorithm rapidly assembles and surveys exact mass data to provide a list of feasible precursor candidates according to the correlation of the chromatographic peak shape profile and other additional filtering criteria (e.g. neutral losses and isotopes). The macro was tested with two families of veterinary drugs, sulfonamides and penicillins, which are known to yield diagnostic product ions when fragmented. Data sets obtained from different food matrices (fish and liver), both at high and low concentration of the target compounds, were investigated in order to evaluate the capabilities and limitations of the reported approach. Finally, other possible applications of this technique, such as the elucidation of elemental compositions based on product ions and corresponding neutral losses, were also presented and discussed.

  3. Spontaneous Mass and Charge Losses from Single Multi-Megadalton Ions Studied by Charge Detection Mass Spectrometry

    Science.gov (United States)

    Keifer, David Z.; Alexander, Andrew W.; Jarrold, Martin F.

    2017-01-01

    Spontaneous mass and charge losses from individual multi-megadalton ions have been observed with charge detection mass spectrometry (CDMS) by trapping single hepatitis B virus (HBV) capsids for 3 s. Gradual increases in the oscillation frequency of single ions in the ion trap are attributed mainly to mass loss (probably solvent, water, and/or salt). The total mass lost during the 3 s trapping period peaks at around 20 kDa for 4 MDa HBV T = 4 capsids. Discrete frequency drops punctuate the gradual increases in the oscillation frequencies. The drops are attributed to a sudden loss of charge. In most cases a single positive charge is lost along with some mass (on average around 1000 Da). Charge loss occurs for over 40% of the trapped ions. It usually occurs near the beginning of the trapping event, and it occurs preferentially in regions of the trap with strong electric fields, indicating that external electric fields promote charge loss. This process may contribute to the decrease in m/z resolution that often occurs with megadalton ions.

  4. The nature of single-ion activity coefficients calculated from potentiometric measurements on cells with liquid junctions

    Energy Technology Data Exchange (ETDEWEB)

    Zarubin, Dmitri P., E-mail: dmitri.zarubin@mtu-net.ru [Department of Physical and Collod Chemistry, Moscow State University of Technology and Management, 73 Zemlyanoi Val, Moscow 109803 (Russian Federation)

    2011-08-15

    Highlights: > Problem of ionic activity coefficients, determined by potentiometry, is reconsidered. > They are found to be functions of mean activity coefficients and transport numbers of ions. > The finding is verified by calculations and comparing the results with reported data. > Calculations are performed for systems with single electrolytes and binary mixtures. - Abstract: Potentiometric measurements on cells with liquid junctions are sometimes used for calculations of single-ion activity coefficients in electrolyte solutions, the incidence of this being increased recently. As surmised by Guggenheim in the 1930s, such coefficients (of ions i), {gamma}{sub i}, are actually complicated functions of mean ionic activity coefficients, {gamma}{sub {+-}}, and transport numbers of ions, t{sub i}. In the present paper specific functions {gamma}{sub i}({gamma}{sub {+-}}, t{sub i}) are derived for a number of cell types with an arbitrary mixture of strong electrolytes in a one-component solvent in the liquid-junction system. The cell types include cells with (i) identical electrodes, (ii) dissimilar electrodes reversible to the same ions, (iii) dissimilar electrodes reversible to ions of opposite charge signs, (iv) dissimilar electrodes reversible to different ions of the same charge sign, and (v) identical reference electrodes and an ion-selective membrane permeable to ions of only one type. Pairs of functions for oppositely charged ions are found to be consistent with the mean ionic activity coefficients as would be expected for pairs of the proper {gamma}{sub i} quantities by definition of {gamma}{sub {+-}}. The functions are tested numerically on some of the reported {gamma}{sub i} datasets that are the more tractable. A generally good agreement is found with data reported for cells with single electrolytes HCl and KCl in solutions, and with binary mixtures in the liquid-junction systems of KCl from the reference solutions and NaCl and HCl from the test solutions. It

  5. Electrode property of single-walled carbon nanotubes in all-solid-state lithium ion battery using polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Y.; Ishii, Y.; Kawasaki, S., E-mail: kawasaki.shinji@nitech.ac.jp [Nagoya Institute of Technology, Gokiso, Showa, Nagoya, Aichi (Japan)

    2016-07-06

    Electrode properties of single-walled carbon nanotubes (SWCNTs) in an all-solid-state lithium ion battery were investigated using poly-ethylene oxide (PEO) solid electrolyte. Charge-discharge curves of SWCNTs in the solid electrolyte cell were successfully observed. It was found that PEO electrolyte decomposes on the surface of SWCNTs.

  6. Electrode property of single-walled carbon nanotubes in all-solid-state lithium ion battery using polymer electrolyte

    Science.gov (United States)

    Sakamoto, Y.; Ishii, Y.; Kawasaki, S.

    2016-07-01

    Electrode properties of single-walled carbon nanotubes (SWCNTs) in an all-solid-state lithium ion battery were investigated using poly-ethylene oxide (PEO) solid electrolyte. Charge-discharge curves of SWCNTs in the solid electrolyte cell were successfully observed. It was found that PEO electrolyte decomposes on the surface of SWCNTs.

  7. Possible wave formation and martensitic transformation of iron particles in copper single crystals during argon ion bombardment

    DEFF Research Database (Denmark)

    Thölén, Anders Ragnar; Li, Chang-Hai; Easterling, K.E.

    1983-01-01

    Thin single crystal copper specimens (thickness ~250 nm) containing coherent iron particles (diameter 40–50 nm) have been bombarded with argon ions (5, 80, and 330 keV). During this process some of the iron particles transform to martensite. The transformation was observed near the exposed surface...

  8. Supramolecular control over molecular magnetic materials: γ-cyclodextrin-templated grid of cobalt(II) single-ion magnets.

    Science.gov (United States)

    Nedelko, Natalia; Kornowicz, Arkadiusz; Justyniak, Iwona; Aleshkevych, Pavlo; Prochowicz, Daniel; Krupiński, Piotr; Dorosh, Orest; Ślawska-Waniewska, Anna; Lewiński, Janusz

    2014-12-15

    Single-ion magnets (SIMs) are potential building blocks of novel quantum computing devices. Unique magnetic properties of SIMs require effective separation of magnetic ions and can be tuned by even slight changes in their coordination sphere geometry. We show that an additional level of tailorability in the design of SIMs can be achieved by organizing magnetic ions into supramolecular architectures, resulting in gaining control over magnetic ion packing. Here, γ-cyclodextrin was used to template magnetic Co(II) and nonmagnetic auxiliary Li(+) ions to form a heterometallic {Co, Li, Li}4 ring. In the sandwich-type complex [(γ-CD)2Co4Li8(H2O)12] spatially separated Co(II) ions are prevented from superexchange magnetic coupling. Ac/dc magnetic and EPR studies demonstrated that individual Co(II) ions with positive zero-field splitting exhibit field-induced slow magnetic relaxation consistent with the SIMs' behavior, which is exceptional in complexes with easy-plane magnetic anisotropy.

  9. Delocalization in Cr3+ luminescence of clinochlore: A pressure-induced transition from single-ion emission to pair emission

    Science.gov (United States)

    O'Bannon, Earl; Williams, Quentin

    2017-10-01

    The luminescence spectra of Cr3+ in (Mg,Fe2+)5Al(Si3Al)O10(OH)8-clinochlore, a layered silicate compound, are reported to pressures of ∼25 GPa at 298 K: our results encompass emission from single-ions, paired neighbors and vibronic lines. A transition from sharp single Cr3+ ion (R-line) dominated emission to Cr-Cr pair (N-Line) dominated emission is observed under compression. Since Cr atoms are confined to a discrete layer within the structure, efficient Cr-Cr exchange only occurs within a single layer; the distance between the layers is too large for significant interlayer coupling to occur. This 2-dimensional, single-layer arrangement gives rise to three distinguishable Cr3+ nearest neighbor pairs. Neighbor lines are assigned based on ferromagnetic coupling of these three emitting pairs. We observe a decrease in the separation between the split components of the R-line under compression, confirming that the Cr sites become less distorted up to at least ∼11.0 GPa. An increase in overlap between eg orbitals of neighboring Cr-ions (corresponding to delocalization of the excited state) under compression also likely occurs. The R-to N-line transition is fully reversible and hysteresis is not observed, indicating that this transition is purely electronic in nature. The intensity transfer between the single-ion and paired-ion emission changes with a ∼1/4th power law as a function of the Cr-Cr separation.

  10. One-volt-driven superfast polymer actuators based on single-ion conductors

    Science.gov (United States)

    Kim, Onnuri; Kim, Hoon; Choi, U. Hyeok; Park, Moon Jeong

    2016-11-01

    The key challenges in the advancement of actuator technologies related to artificial muscles include fast-response time, low operation voltages and durability. Although several researchers have tackled these challenges over the last few decades, no breakthrough has been made. Here we describe a platform for the development of soft actuators that moves a few millimetres under 1 V in air, with a superfast response time of tens of milliseconds. An essential component of this actuator is the single-ion-conducting polymers that contain well-defined ionic domains through the introduction of zwitterions; this achieved an exceptionally high dielectric constant of 76 and a 300-fold enhancement in ionic conductivity. Moreover, the actuator demonstrated long-term durability, with negligible changes in the actuator stroke over 20,000 cycles in air. Owing to its low-power consumption (only 4 mW), we believe that this actuator could pave the way for cutting-edge biomimetic technologies in the future.

  11. Flexible single-walled carbon nanotube/polycellulose papers for lithium-ion batteries.

    Science.gov (United States)

    Wang, Jin; Li, Linlin; Wong, Chui Ling; Madhavi, Srinivasan

    2012-12-14

    Flexible and highly conductive single-walled carbon nanotube/polycellulose papers (SWCNT/PPs) were developed as current collectors for lithium-ion batteries by a simple and scalable process. The flexible electrodes based on SWCNT/PP conductors consisted of a unique three-dimensional interwoven structure of electrode materials and cellulose fibers with CNTs and exhibited flexibility, good electrochemical performance and excellent cyclic stability. Full cells using Li(4)Ti(5)O(12) and LiFePO(4) electrodes based on SWCNT/PPs showed a first discharge capacity of 153.5 mA h g(-1) with Coulombic efficiencies of 90.6% at 0.1 C and discharge capacity of 102.6 mA h g(-1) at high rate (10 C). Full cells based SWCNT/PP conductors showed higher capacities and lower electrochemical interfacial resistance compared to metallic current collectors. Half cells using anatase TiO(2) hierarchical spheres based on SWCNT/PP conductors also exhibited outstanding electrochemical performance, verifying the stability of SWCNT/PP conductors to various electrode materials. Our results demonstrated the potential versatility of composite electrodes and conductive SWCNT/PPs for flexible and portable micropower devices.

  12. Polymerized planar suspended lipid bilayers for single ion channel recordings: comparison of several dienoyl lipids.

    Science.gov (United States)

    Heitz, Benjamin A; Xu, Juhua; Jones, Ian W; Keogh, John P; Comi, Troy J; Hall, Henry K; Aspinwall, Craig A; Saavedra, S Scott

    2011-03-01

    The stabilization of suspended planar lipid membranes, or black lipid membranes (BLMs), through polymerization of mono- and bis-functionalized dienoyl lipids was investigated. Electrical properties, including capacitance, conductance, and dielectric breakdown voltage, were determined for BLMs composed of mono-DenPC, bis-DenPC, mono-SorbPC, and bis-SorbPC both prior to and following photopolymerization, with diphytanoyl phosphocholine (DPhPC) serving as a control. Poly(lipid) BLMs exhibited significantly longer lifetimes and increased the stability of air-water transfers. BLM stability followed the order bis-DenPC > mono-DenPC ≈ mono-SorbPC > bis-SorbPC. The conductance of bis-SorbPC BLMs was significantly higher than that of the other lipids, which is attributed to a high density of hydrophilic pores, resulting in relatively unstable membranes. The use of poly(lipid) BLMs as matrices for supporting the activity of an ion channel protein (IC) was explored using α-hemolysin (α-HL), a model IC. Characteristic i-V plots of α-HL were maintained following photopolymerization of bis-DenPC, mono-DenPC, and mono-SorbPC, demonstrating the utility of these materials for preparing more durable BLMs for single-channel recordings of reconstituted ICs.

  13. MeV single-ion beam irradiation of mammalian cells using the Surrey vertical nanobeam, compared with broad proton beam and X-ray irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Jeynes, J.C.G.; Merchant, M.J.; Kirkby, K.; Kirkby, N. [Surrey Ion Beam Center, Faculty of Engineering and Physical Science, University of Surrey, Guildford Surrey, GU2 7XH (United Kingdom); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: •Recently completed nanobeam at the Surrey Ion Beam Centre was used. •3.8-MeV single and broad proton beams irradiated Chinese hamster cells. •Cell survival curves were measured and compared with 300-kV X-ray irradiation. •Single ion irradiation had a lower survival part at ultra-low dose. •It implies hypersensitivity, bystander effect and cell cycle phase of cell death. -- Abstract: As a part of a systematic study on mechanisms involved in physical cancer therapies, this work investigated response of mammalian cells to ultra-low-dose ion beam irradiation. The ion beam irradiation was performed using the recently completed nanobeam facility at the Surrey Ion Beam Centre. A scanning focused vertical ion nano-beam was applied to irradiate Chinese hamster V79 cells. The V79 cells were irradiated in two different beam modes, namely, focused single ion beam and defocused scanning broad ion beam of 3.8-MeV protons. The single ion beam was capable of irradiating a single cell with a precisely controlled number of the ions to extremely low doses. After irradiation and cell incubation, the number of surviving colonies as a function of the number of the irradiating ions was measured for the cell survival fraction curve. A lower survival for the single ion beam irradiation than that of the broad beam case implied the hypersensitivity and bystander effect. The ion-beam-induced cell survival curves were compared with that from 300-kV X-ray irradiation. Theoretical studies indicated that the cell death in single ion irradiation mainly occurred in the cell cycle phases of cell division and intervals between the cell division and the DNA replication. The success in the experiment demonstrated the Surrey vertical nanobeam successfully completed.

  14. Single-color, in situ photolithography marking of individual CdTe/ZnTe quantum dots containing a single Mn{sup 2+} ion

    Energy Technology Data Exchange (ETDEWEB)

    Sawicki, K.; Malinowski, F. K.; Gałkowski, K.; Jakubczyk, T.; Kossacki, P.; Pacuski, W.; Suffczyński, J., E-mail: Jan.Suffczynski@fuw.edu.pl [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5 St., PL-02-093 Warsaw (Poland)

    2015-01-05

    A simple, single-color method for permanent marking of the position of individual self-assembled semiconductor Quantum Dots (QDs) at cryogenic temperatures is reported. The method combines in situ photolithography with standard micro-photoluminescence spectroscopy. Its utility is proven by a systematic magnetooptical study of a single CdTe/ZnTe QD containing a Mn{sup 2+} ion, where a magnetic field of up to 10 T in two orthogonal, Faraday and Voigt, configurations is applied to the same QD. The presented approach can be applied to a wide range of solid state nanoemitters.

  15. Fractioning electrodialysis: a current induced ion exchange process

    NARCIS (Netherlands)

    Galama, A.H.; Daubaras, G.; Burheim, O.S.; Rijnaarts, H.; Post, J.W.

    2014-01-01

    In desalination often multi ionic compositions are encountered. A preferential removal of multivalent ions over monovalent ions can be of interest to prevent scaling in the desalination process. Recently, a novel fractionating electrodialysis stack is described by Zhang et al., 2012 (in Sep. purify.

  16. Fractioning electrodialysis : a current induced ion exchange process

    NARCIS (Netherlands)

    Galama, A. H.; Daubaras, G.; Burheim, O. S.; Rijnaarts, H. H. M.; Post, J. W.

    2014-01-01

    In desalination often multi ionic compositions are encountered. A preferential removal of multivalent ions over monovalent ions can be of interest to prevent scaling in the desalination process. Recently, a novel fractionating electrodialysis stack is described by Zhang et al., 2012 (in Sep. purify.

  17. Dark-state suppression and optimization of laser cooling and fluorescence in a trapped alkaline-earth-metal single ion

    CERN Document Server

    Lindvall, T; Tittonen, I; Madej, A A; 10.1103/PhysRevA.86.033403

    2012-01-01

    We study the formation and destabilization of dark states in a single trapped 88Sr+ ion caused by the cooling and repumping laser fields required for Doppler cooling and fluorescence detection of the ion. By numerically solving the time-dependent density matrix equations for the eight-level system consisting of the sublevels of the 5s 2S1/2, 5p 2P1/2, and 4d 2D3/2 states, we analyze the different types of dark states and how to prevent them in order to maximize the scattering rate, which is crucial for both the cooling and the detection of the ion. The influence of the laser linewidths and ion motion on the scattering rate and the dark resonances is studied. The calculations are then compared with experimental results obtained with an endcap ion trap system located at the National Research Council of Canada and found to be in good agreement. The results are applicable also to other alkaline earth ions and isotopes without hyperfine structure.

  18. (55)Mn pulsed ENDOR spectroscopy of Mn(2+) ions in ZnO thin films and single crystal.

    Science.gov (United States)

    Böttcher, Rolf; Pöppl, Andreas; Lorenz, Michael; Friedländer, Stefan; Spemann, Daniel; Grundmann, Marius

    2014-08-01

    (55)Mn pulsed electron nuclear double resonance (ENDOR) experiments were performed at X-band on high spin S=5/2 Mn(2+) ions incorporated at zinc lattice sites in heteroepitaxial ZnO thin films. The films have been prepared by pulsed laser deposition and the manganese ions were doped during the growth process. We examine how the c/a lattice axes ratio of the ZnO films influences the (55)Mn hyperfine (hf) and nuclear quadrupole (nq) coupling parameters of the Mn(2+) probe ions. The results are compared with those obtained for Mn(2+) ions present as impurities in ZnO single crystals and revealed that the (55)Mn nq coupling monitors sensitively the structural distortions in the bonding environment of the Mn(2+) ions. The experiments provided the full axially symmetric (55)Mn hf and nq interaction tensors. The latter is found to be very sensitive to small axial distortions of the MnO4 tetrahedrons. In particular, the (55)Mn pulsed ENDOR spectra of the ZnO:Mn thin films are strongly subjected to strain effects in the nq coupling parameter indicating a variation of the local structural parameters for the heteroepitaxial films. In the analysis of the (55)Mn pulsed ENDOR spectra the axial and cubic zero field splitting of the Mn(2+) ions was taken into account and intensity effects in the ENDOR spectra due to the zero field splitting effects were discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Molecular dynamics study of radiation damage and microstructure evolution of zigzag single-walled carbon nanotubes under carbon ion incidence

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huan [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Tang, Xiaobin, E-mail: tangxiaobin@nuaa.edu.cn [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Jiangsu Key Laboratory of Nuclear Energy Equipment Materials Engineering, Nanjing (China); Chen, Feida; Huang, Hai; Liu, Jian [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Chen, Da [Department of Nuclear Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing (China); Jiangsu Key Laboratory of Nuclear Energy Equipment Materials Engineering, Nanjing (China)

    2016-07-01

    Highlights: • Various incident sites of CNTs are classified into three types for the first time. • Different ion energies and fluences are considered to study the radiation damage. • CNTs have ability to heal the radiation-induced damage at higher temperature. • Stability of a large-diameter tube excels in a slim one under the same conditions. - Abstract: The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

  20. Single potential electrodeposition of nanostructured battery materials for lithium-ion batteries

    Science.gov (United States)

    Mosby, James Matthew

    The increasing reliance on portable electronics is continuing to fuel research in the area of low power lithium-ion batteries, while a new surge in research for high power lithium-ion batteries has been sparked by the demand for plug-in hybrid electric vehicles (PHEV) and plug-in electric vehicles (PEV). To compete with current lead-acid battery chemistry, a few of the shortcomings of lithium-ion battery chemistry need to be addressed. The three main drawbacks of lithium-ion batteries for this application are: (1) low power density, (2) safety, and (3) the high cost of manufacturing. This dissertation covers the development of a low cost fabrication technique for an alternative anode material with high surface area geometries. The anode material is safer than the conventional anode material in lithium-ion batteries and the high surface area geometries permit higher power densities to be achieved. Electrodeposition is an inexpensive alternative method for synthesizing materials for electronics, energy conversion and energy storage applications relative to traditional solid state techniques. These techniques led to expensive device fabrication. Unlike most solid state synthesis routes, electrodeposition can usually be performed from common solutions and at moderate conditions. Three other benefits of using electrodeposition are: (1) it allows precise control of composition and crystallinity, (2) it provides the ability to deposit on complex shapes, and (3) it can deposit materials with nanoscale dimensions. The use of electrodeposition for alternative anode materials results in the deposition of the material directly onto the current collector that is used for the battery testing and applications without the need of additional binders and with excellent electrical contact. While this improves the characterization of the material and lowers the weight of the non-active materials within a battery, it also allows the anode to be deposited onto current collectors with

  1. Effect of magnesium ions and temperature on the sequence-dependent curvature of DNA restriction fragments

    Energy Technology Data Exchange (ETDEWEB)

    Stellwagen, Nancy C; Lu Yongjun, E-mail: nancy-stellwagen@uiowa.ed [Department of Biochemistry, University of Iowa, Iowa City, IA 52242 (United States)

    2010-12-15

    Transient electric birefringence has been used to quantify the curvature of two DNA restriction fragments, a 199-base-pair fragment taken from the origin of replication of the M13 bacteriophage and a 207-base-pair fragment taken from the VP1 gene in the SV40 minichromosome. Stable curvature in the SV40 and M13 restriction fragments is due to a series of closely spaced A tracts, runs of 4-6 contiguous adenine residues located within 40 or 60 base pair 'curvature modules' near the center of each fragment. The M13 and SV40 restriction fragments exhibit bends of {approx} 45{sup 0} in solutions containing monovalent cations and {approx} 60{sup 0} in solutions containing Mg{sup 2+} ions. The curvature is not localized at a single site but is distributed over the various A tracts in the curvature modules. Thermal denaturation studies indicate that the curvature in the M13 and SV40 restriction fragments remains constant up to 30 {sup 0}C in solutions containing monovalent cations, and up to 40 {sup 0}C in solutions containing Mg{sup 2+} ions, before beginning to decrease slowly with increasing temperature. Hence, stable curvature in these DNA restriction fragments exists at the biologically important temperature of 37 {sup 0}C.

  2. Forbidden M1 and E2 transitions in monovalent atoms and ions

    CERN Document Server

    Safronova, U I; Johnson, W R

    2016-01-01

    We carried out a systematic high-precision relativistic study of the forbidden magnetic-dipole and electric-quadrupole transitions in Ca+, Rb, Sr+, Cs, Ba+, Fr, Ra+, Ac2+, and Th3+. This work is motivated by the importance of these transitions for tests of fundamental physics and precision measurements. The relative importance of the relativistic, correlation, Breit correction, and contributions of negative-energy states is investigated. Recommended values of reduced matrix elements are presented together with their uncertainties. The matrix elements and resulting lifetimes are compared with other theoretical values and with experiment where available.

  3. Determination of trace inorganic anions in anionic surfactants by single-pump column-switching ion chromatography

    Institute of Scientific and Technical Information of China (English)

    Jia Jie Zhang; Hai Bao Zhu; Yan Zhu

    2012-01-01

    An ion chromatography method has been proposed for the determination of three common inorganic anions (chloride,nitrate and sulfate) in anionic surfactants using a single pump system.The new system consists of an ion exclusion column,a concentrator column,and an anion exchange column connected in series via two 6-ports valves in a Dionex ICS-2000 ion chromatograph.The valves were switched several times for removing surfactants,concentrating and separating the three anions.The chromatographic conditions were optimized.Detection limits (S/N =3) were in the range of 0.10-0.68 μg/L.The relative standard deviations (RSDs)of peak area were less than 4.6%.The recoveries were in the range of 84.1-112.6%.

  4. Single element of the matrix source of negative hydrogen ions: Measurements of the extracted currents combined with diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, D., E-mail: yordanov@phys.uni-sofia.bg; Lishev, St.; Shivarova, A. [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria)

    2016-02-15

    Combining measurements of the extracted currents with probe and laser-photodetachment diagnostics, the study is an extension of recent tests of factors and gas-discharge conditions stimulating the extraction of volume produced negative ions. The experiment is in a single element of a rf source with the design of a matrix of small-radius inductively driven discharges. The results are for the electron and negative-ion densities, for the plasma potential and for the electronegativity in the vicinity of the plasma electrode as well as for the currents of the extracted negative ions and electrons. The plasma-electrode bias and the rf power have been varied. Necessity of a high bias to the plasma electrode and stable linear increase of the extracted currents with the rf power are the main conclusions.

  5. Molecular dynamics of glycine ions in alanine doped TGS single crystal as probed by polarized laser raman spectroscopy

    Science.gov (United States)

    Bajpai, P. K.; Verma, A. L.

    2012-10-01

    Polarized Raman spectra of pure and alanine doped tri-glycine sulfate (TGS) single crystals at 12 K in different scattering geometries are analyzed. Sub species modes due to three crystallographically distinguishable glycine ions G (I), G (II) and G (III) are assigned. It is observed that alanine doping does not change the crystalline field and acts as local perturbation only. The major changes due to doping are observed in the relative intensities of different modes; most of the modes associated with G (I) and SO42- ions show reversal behavior in relative intensity at high doping concentration. The observed spectral changes are analyzed in terms of reorientation of G (I) ions with sub species modes of G (II)/ G (III) following the reorientation due to complex hydrogen bonding network.

  6. Potent neutralization of influenza A virus by a single-domain antibody blocking M2 ion channel protein.

    Directory of Open Access Journals (Sweden)

    Guowei Wei

    Full Text Available Influenza A virus poses serious health threat to humans. Neutralizing antibodies against the highly conserved M2 ion channel is thought to offer broad protection against influenza A viruses. Here, we screened synthetic Camel single-domain antibody (VHH libraries against native M2 ion channel protein. One of the isolated VHHs, M2-7A, specifically bound to M2-expressed cell membrane as well as influenza A virion, inhibited replication of both amantadine-sensitive and resistant influenza A viruses in vitro, and protected mice from a lethal influenza virus challenge. Moreover, M2-7A showed blocking activity for proton influx through M2 ion channel. These pieces of evidence collectively demonstrate for the first time that a neutralizing antibody against M2 with broad specificity is achievable, and M2-7A may have potential for cross protection against a number of variants and subtypes of influenza A viruses.

  7. Single-Ion Block Copoly(ionic liquid)s as Electrolytes for All-Solid State Lithium Batteries.

    Science.gov (United States)

    Porcarelli, Luca; Shaplov, Alexander S; Salsamendi, Maitane; Nair, Jijeesh R; Vygodskii, Yakov S; Mecerreyes, David; Gerbaldi, Claudio

    2016-04-27

    Polymer electrolytes have been proposed as replacement for conventional liquid electrolytes in lithium-ion batteries (LIBs) due to their intrinsic enhanced safety. Nevertheless, the power delivery of these materials is limited by the concentration gradient of the lithium salt. Single-ion conducting polyelectrolytes represent the ideal solution since their nature prevents polarization phenomena. Herein, the preparation of a new family of single-ion conducting block copolymer polyelectrolytes via reversible addition-fragmentation chain transfer polymerization technique is reported. These copolymers comprise poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) and poly(ethylene glycol) methyl ether methacrylate blocks. The obtained polyelectrolytes show low Tg values in the range of -61 to 0.6 °C, comparatively high ionic conductivity (up to 2.3 × 10(-6) and 1.2 × 10(-5) S cm(-1) at 25 and 55 °C, respectively), wide electrochemical stability (up to 4.5 V versus Li(+)/Li), and a lithium-ion transference number close to unity (0.83). Owing to the combination of all mentioned properties, the prepared polymer materials were used as solid polyelectrolytes and as binders in the elaboration of lithium-metal battery prototypes with high charge/discharge efficiency and excellent specific capacity (up to 130 mAh g(-1)) at C/15 rate.

  8. A transportable 40Ca+ single-ion clock with $7.7\\times 10^{-17}$ systematic uncertainty

    CERN Document Server

    Cao, Jian; Shang, Junjuan; Cui, Kaifeng; Yuan, Jinbo; Chao, Sijia; Wang, Shaomao; Shu, Hualin; Huang, Xueren

    2016-01-01

    A transportable optical clock refer to the $4s^2S_{1/2}-3d^2D_{5/2}$ electric quadrupole transition at 729 nm of single $^{40}Ca^+$ trapped in mini Paul trap has been developed. The physical system of $^{40}Ca^+$ optical clock is re-engineered from a bulky and complex setup to an integration of two subsystems: a compact single ion unit including ion trapping and detection modules, and a compact laser unit including laser sources, beam distributor and frequency reference modules. Apart from the electronics, the whole equipment has been constructed within a volume of 0.54 $m^3$. The systematic fractional uncertainty has been evaluated to be $7.7\\times 10^{-17}$, and the Allan deviation fits to be $2.3\\times {10}^{-14}/\\sqrt{\\tau}$ by clock self-comparison with a probe pulse time 20 ms.

  9. Measurement of the modal birefringence of single-mode K(+) ion-exchanged planar waveguides with polarimetric interferometry.

    Science.gov (United States)

    Qi, Z M; Itoh, K; Murabayashi, M

    2000-11-01

    The polarimetric interference pattern on the surface of single-mode planar waveguides made by potassium ion exchange in soda-lime glass substrates can be observed through a 45 degrees analyzer, which allows for the high-precision measurement of the modal birefringence of samples in a wide range of 0 to 5 x 10(-4). Using this method, believed to be new, we investigated the effects of exchange temperature and time on the modal birefringence of single-mode potassium ion-exchanged waveguides. The modal birefringence profile was achieved by measurement of the variation of the phase difference between the TE(0) and the TM(0) modes with hydrofluoric-acid-etching depth of the sample.

  10. Thermodynamic Properties of Random Transverse Field Mixed Spin System in the Presence of Single-Ion Anisotropy

    Institute of Scientific and Technical Information of China (English)

    ZHANGYa-Nan; YANShi-Lei

    2003-01-01

    We study the thermodynamic properties of random transverse field mixed spin system in the presence of single-ion anisotropy on a square lattice. By making use of the effective field theory and a cutting approximation, the detailed phase diagrams are described and some interesting results are found under trimodal random transverse field distribution. A small single-ion anisotropy can magnify magnetic ordering region at low temperatures and existence of a large transverse field can assist the occurrence of reentrant phenomena. With increasing disorder, second-order phase transitions are shown to change into first-order phase transitions. The trajectory of the tricritical point in the phase space as a function of disorder is presented. These indicate a strong correlation with the corresponding to trimodal transverse field distribution.

  11. Detecting single graphene layer by using fluorescence from high-speed Ar^7+ ion

    Science.gov (United States)

    Miyamoto, Yoshiyuki; Zhang, Hong

    2008-03-01

    A highly-charged-ion interacting with graphite causes structural change in nano-scales [1]. While when the ion's kinetic energy reaches few MeVs, the induced is not the structural change but electronic excitation. An experiment [2] showed fluorescence from Ar^7+ ions penetrating through carbon foil with kinetic energy of 2 MeV. Motivated by this experiment, we tested interaction between an Ar^7+ ion and a graphene sheet by the time-dependent density functional approach, and found that the electronic excitation in the Ar^ 7+ ion is also the case even when the incident kinetic energy is 500 KeV and the target thickness is only mono-atomic layer. This simulation suggests the possibility of detecting a suspended mono-atomic layer of graphene [3] by monitoring fluorescence from the penetrated Ar^7+ ions. We will discuss its importance for analyzing bombardment of solids by highly charged, high-speed ions and possible experiments according to the present result. References: [1] T. Meguro, et al., Appl. Phys. Lett 79, 3866 (2001). [2] S. Bashkin, H. Oona, E. Veje, Phys, Rev. A25, 417 (1982). [3] J. Mayer et al., Nature (London), 446, 60 (2007).

  12. Magnetic Properties of One-Dimensional Ferrimagnetic Mixed (1,3/2) Spin Chain with Single-Ion Anisotropy

    Institute of Scientific and Technical Information of China (English)

    Ekrem Aydiner

    2004-01-01

    @@ We have carried out Monte Carlo simulations to study the magnetic properties of a mixed S = 1 and S = 3/2ferrimagnetic system interacting antiferromagnetically on a one-dimensional spin chain with single-ion anisotropy.It has been shown that at sufficiently low temperatures, the system has magnetization plateaus near the ground state under an external field. Other interesting physical quantities such as the specific heat and the Neel order at low temperatures are also discussed.

  13. Synthesis of Large-Sized Single-Crystal Hexagonal Boron Nitride Domains on Nickel Foils by Ion Beam Sputtering Deposition.

    Science.gov (United States)

    Wang, Haolin; Zhang, Xingwang; Liu, Heng; Yin, Zhigang; Meng, Junhua; Xia, Jing; Meng, Xiang-Min; Wu, Jinliang; You, Jingbi

    2015-12-22

    Large-sized single-crystal h-BN domains with a lateral size up to 100 μm are synthesized on Ni foils by ion-beam sputtering deposition. The nucleation density of h-BN is dramatically decreased by reducing the concentrations of both active sites and species on the Ni surface through a brief in situ pretreatment of the substrate and optimization of the growth parameters, enabling the growth of large-sized domains.

  14. Correlation character of ionic current fluctuations: analysis of ion current through a voltage-dependent potassium single channel.

    Science.gov (United States)

    Tong-Han, Lan; Huang, Xi; Jia-Rui, Lin

    2005-10-03

    The gating of ion channels has widely been modeled by assuming the transition between open and closed states is a memoryless process. Nevertheless, the statistical analysis of an ionic current signal recorded from voltage dependence K(+) single channel is presented. Calculating the sample auto-correlation function of the ionic current based on the digitized signals, rather than the sequence of open and closed states duration time. The results provide evidence for the existence of memory. For different voltages, the ion channel current fluctuation has different correlation attributions. The correlations in data generated by simulation of two Markov models, on one hand, auto-correlation function of the ionic current shows a weaker memory, after a delayed period of time, the attribute of memory does not exist; on the other hand, the correlation depends on the number of states in the Markov model. For V(p)=-60 mV pipette potential, spectral analysis of ion channel current was conducted, the result indicates that the spectrum is not a flat spectrum, the data set from ionic current fluctuations shows considerable variability with a broad 1/f -like spectrum, alpha=1.261+/-0.24. Thus the ion current fluctuations give information about the kinetics of the channel protein, the results suggest the correlation character of ion channel protein nonlinear kinetics regardless of whether the channel is in open or closed state.

  15. Molecular dynamics study of radiation damage and microstructure evolution of zigzag single-walled carbon nanotubes under carbon ion incidence

    Science.gov (United States)

    Li, Huan; Tang, Xiaobin; Chen, Feida; Huang, Hai; Liu, Jian; Chen, Da

    2016-07-01

    The radiation damage and microstructure evolution of different zigzag single-walled carbon nanotubes (SWCNTs) were investigated under incident carbon ion by molecular dynamics (MD) simulations. The radiation damage of SWCNTs under incident carbon ion with energy ranging from 25 eV to 1 keV at 300 K showed many differences at different incident sites, and the defect production increased to the maximum value with the increase in incident ion energy, and slightly decreased but stayed fairly stable within the majority of the energy range. The maximum damage of SWCNTs appeared when the incident ion energy reached 200 eV and the level of damage was directly proportional to incident ion fluence. The radiation damage was also studied at 100 K and 700 K and the defect production decreased distinctly with rising temperature because radiation-induced defects would anneal and recombine by saturating dangling bonds and reconstructing carbon network at the higher temperature. Furthermore, the stability of a large-diameter tube surpassed that of a thin one under the same radiation environments.

  16. Diamond single crystal-surface modification under high- fluence ion irradiation

    Science.gov (United States)

    Anikin, V. A.; Borisov, A. M.; Kazakov, V. A.; Mashkova, E. S.; Palyanov, Yu N.; Popov, V. P.; Shmytkova, E. A.; Sigalaev, S. K.

    2016-09-01

    The modification of (111) face of synthetic diamond has been studied experimentally for high-fluence 30 keV argon bombardment. It has been found that ion irradiation leads to the electrically conductive layer formation the sheet resistance of which decreases more than 100 times while changing the temperature of the irradiated diamond from 70 to 400 oC. This effect, as well as significant changes of optical transmittance after ion irradiation are associated with ion-induced structural changes of irradiated diamond obtained by the methods of Raman spectroscopy.

  17. Motional Quantum State Engineering Via a Single Laser-ion Interaction

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shibiao

    2001-01-01

    We propose a scheme to prepare superpositions of several Fock states for the one-dimensional motion of a trapped ion. In the scheme the ion is simultaneously excited by N+1 laser beams, with the nth laser tuned to the nth upper vibrational sideband. After a short interaction time, a measurement of the internal state may project the vibrational motion onto a superposition of the first N+1 Fock states. The scheme can be easily generalized to synthesize entangled states for the two-dimensional ion motion.

  18. Characterization and Monte Carlo simulation of single ion Geiger mode avalanche diodes integrated with a quantum dot nanostructure

    Science.gov (United States)

    Sharma, Peter; Abraham, J. B. S.; Ten Eyck, G.; Childs, K. D.; Bielejec, E.; Carroll, M. S.

    Detection of single ion implantation within a nanostructure is necessary for the high yield fabrication of implanted donor-based quantum computing architectures. Single ion Geiger mode avalanche (SIGMA) diodes with a laterally integrated nanostructure capable of forming a quantum dot were fabricated and characterized using photon pulses. The detection efficiency of this design was measured as a function of wavelength, lateral position, and for varying delay times between the photon pulse and the overbias detection window. Monte Carlo simulations based only on the random diffusion of photo-generated carriers and the geometrical placement of the avalanche region agrees qualitatively with device characterization. Based on these results, SIGMA detection efficiency appears to be determined solely by the diffusion of photo-generated electron-hole pairs into a buried avalanche region. Device performance is then highly dependent on the uniformity of the underlying silicon substrate and the proximity of photo-generated carriers to the silicon-silicon dioxide interface, which are the most important limiting factors for reaching the single ion detection limit with SIGMA detectors. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  19. Single impacts of keV fullerene ions on free standing graphene: Emission of ions and electrons from confined volume

    Energy Technology Data Exchange (ETDEWEB)

    Verkhoturov, Stanislav V.; Geng, Sheng; Schweikert, Emile A., E-mail: schweikert@chem.tamu.edu [Department of Chemistry, Texas A& M University, College Station, Texas 77843-3144 (United States); Czerwinski, Bartlomiej [Institute of Condensed Matter and Nanosciences–Bio and Soft Matter (IMCN/BSMA), Université Catholique de Louvain, 1 Croix du Sud, B-1348 Louvain-la-Neuve (Belgium); Applied Physics, Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-971 87 Luleå (Sweden); Young, Amanda E. [Materials Characterization Facility, Texas A& M University, College Station, Texas 77843-3122 (United States); Delcorte, Arnaud [Institute of Condensed Matter and Nanosciences–Bio and Soft Matter (IMCN/BSMA), Université Catholique de Louvain, 1 Croix du Sud, B-1348 Louvain-la-Neuve (Belgium)

    2015-10-28

    We present the first data from individual C{sub 60} impacting one to four layer graphene at 25 and 50 keV. Negative secondary ions and electrons emitted in transmission were recorded separately from each impact. The yields for C{sub n}{sup −} clusters are above 10% for n ≤ 4, they oscillate with electron affinities and decrease exponentially with n. The result can be explained with the aid of MD simulation as a post-collision process where sufficient vibrational energy is accumulated around the rim of the impact hole for sputtering of carbon clusters. The ionization probability can be estimated by comparing experimental yields of C{sub n}{sup −} with those of C{sub n}{sup 0} from MD simulation, where it increases exponentially with n. The ionization probability can be approximated with ejecta from a thermally excited (3700 K) rim damped by cluster fragmentation and electron detachment. The experimental electron probability distributions are Poisson-like. On average, three electrons of thermal energies are emitted per impact. The thermal excitation model invoked for C{sub n}{sup −} emission can also explain the emission of electrons. The interaction of C{sub 60} with graphene is fundamentally different from impacts on 3D targets. A key characteristic is the high degree of ionization of the ejecta.

  20. Explorations of a series of second order nonlinear optical materials based on monovalent metal gold(III) iodates.

    Science.gov (United States)

    Huang, Chao; Hu, Chun-Li; Xu, Xiang; Yang, Bing-Ping; Mao, Jiang-Gao

    2013-10-07

    The syntheses, crystal structures, and characterizations of a series of monovalent metal gold(III) iodates, namely, α-NaAu(IO3)4, β-NaAu(IO3)4, RbAu(IO3)4, α-CsAu(IO3)4, β-CsAu(IO3)4, and AgAu(IO3)4 are reported. Their structures feature Au(IO3)4(-) anions that are separated by alkali metal ions or silver(I) ions. The Au(IO3)4(-) anions in the polar α-NaAu(IO3)4, RbAu(IO3)4, and α-CsAu(IO3)4 are polar with all four iodate groups being located only above (or below) the AuO4 square plane (cis- configuration). α-NaAu(IO3)4, RbAu(IO3)4, and α-CsAu(IO3)4 display moderate strong Second-Hamonic Generation (SHG) responses of 1.17 ×, 1.33 ×, and 1.17 × KTP (KTiOPO4), respectively, and all three materials are type-I phase-matchable. The Au(IO3)4(-) anions in centrysymmetric β-NaAu(IO3)4, β-CsAu(IO3)4, and AgAu(IO3)4 are nonpolar with the four iodate groups of the Au(IO3)4(-) anion being located both above and below the AuO4 square plane (trans- configuration). IR and UV spectra, luminescent and ferroelectric properties have also been measured. Theoretical calculations of their optical properties based on density functional theory (DFT) methods were performed by using the CASTEP total-energy code.

  1. Europium ion as a probe for binding sites to carrageenans

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Ana P.; Goncalves, Rogeria R.; Serra, Osvaldo A. [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo 14040-901 (Brazil); Zaniquelli, Maria Elisabete D. [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo 14040-901 (Brazil)], E-mail: medzaniquelli@ffclrp.usp.br; Wong, Kenneth [Laboratorio de Fisico-Quimica, Centro de Pesquisas de Paulinia, Rhodia Brasil, Paulinia, Sao Paulo (Brazil)

    2007-12-15

    Carrageenans, sulfated polysaccharides extracted from red algae, present a coil-helix transition and helix aggregation dependence on the type and concentration of counterions. In this study, we focus attention on a mixed valence counterion system: Eu{sup 3+}/Na{sup +} or K{sup +} with different gel-forming carrageenans: kappa, iota, and kappa-2. Results of stationary and time-dependent luminescence showed to be a suitable tool to probe ion binding to both the negatively charged sulfate group and the hydroxyl groups present in the biopolymer. For lower europium ion concentrations, a single longer decay emission lifetime was detected, which was attributed to the binding of europium ion to the carrageenan sulfate groups. An additional decay ascribed to europium binding to hydroxyl groups was observed above a threshold concentration, and this decay was dependent on the carrageenan charge density. Symmetry of the europium ion microenvironment was estimated by the ratio between the intensities of its emission bands, which has been shown to depend on the concentration of europium ions and on the specificity of the monovalent counterion bound to the carrageenan.

  2. Export of a single drug molecule in two transport cycles by a multidrug efflux pump.

    Science.gov (United States)

    Fluman, Nir; Adler, Julia; Rotenberg, Susan A; Brown, Melissa H; Bibi, Eitan

    2014-08-08

    Secondary multidrug transporters use ion concentration gradients to energize the removal from cells of various antibiotics. The Escherichia coli multidrug transporter MdfA exchanges a single proton with a single monovalent cationic drug molecule. This stoichiometry renders the efflux of divalent cationic drugs energetically unfavourable, as it requires exchange with at least two protons. Here we show that surprisingly, MdfA catalyses efflux of divalent cations, provided that they have a unique architecture: the two charged moieties must be separated by a long linker. These drugs are exchanged for two protons despite the apparent inability of MdfA to exchange two protons for a single drug molecule. Our results suggest that these drugs are transported in two consecutive transport cycles, where each cationic moiety is transported as if it were a separate substrate. We propose that secondary transport can adopt a processive-like mode of action, thus expanding the substrate spectrum of multidrug transporters.

  3. Media selection in ion-exchange chromatography in a single microplate.

    Science.gov (United States)

    Cabanne, Charlotte; Santarelli, Xavier

    2014-01-01

    High-throughput process development is more and more used in chromatography. Limitations are the tools provided by the manufacturers. Here, we describe a method to select chromatographic media for ion-exchange chromatography using a 96-well filter microplate.

  4. Single-ion magnet behaviour in mononuclear and two-dimensional dicyanamide-containing cobalt(ii) complexes.

    Science.gov (United States)

    Switlicka-Olszewska, Anna; Palion-Gazda, Joanna; Klemens, Tomasz; Machura, Barbara; Vallejo, Julia; Cano, Joan; Lloret, Francesc; Julve, Miguel

    2016-06-21

    Three cobalt(ii) complexes of formulae [Co(dca)2(bim)4] (), [Co(dca)2(bim)2]n () and [Co(dca)2(bmim)2]n () [dca = dicyanamide, bim = 1-benzylimidazole and bmim = 1-benzyl-2-methylimidazole] were prepared and structurally analyzed by single-crystal X-ray crystallography. Compound is a mononuclear species where the cobalt(ii) ion is six-coordinate with four bim molecules in the equatorial positions [Co-Nbim = 2.1546(15) and 2.1489(15) Å] and two trans-positioned dca ligands [Co-Ndca = 2.1575(18) Å] in the axial sites of a somewhat distorted octahedral surrounding. The structures of and consist of two-dimensional grids of cobalt(ii) ions where each metal atom is linked to the other four metal centres by single dca bridges exhibiting the μ1,5-dca coordination mode [Co-Ndca = 2.190(3)-2.220(3) () and 2.127(3)-2.153(3) Å ()]. Two trans-coordinated bim ()/bmim () molecules achieve the six-coordination around each cobalt(ii) ion [Co-Nbim = 2.128(3)-2.134(4) Å () and Co-Nbmim = 2.156(3)-2.163(39) Å ()]. The values of the cobalt-cobalt separation through the single dca bridges are 8.927(2) and 8.968(2) Å in and 8.7110(5) and 8.7158(5) Å in . Magnetic susceptibility measurements for in the temperature range of 2.0-300 K reveal that these compounds behave as magnetically isolated high-spin cobalt(ii) ions with a significant orbital contribution to the magnetic moment. Alternating current (ac) magnetic susceptibility measurements for show a frequency dependence of out-of-phase susceptibility under static applied fields in the range of 500-2500 G, a feature which is characteristic of the single-ion magnet behaviour (SIM) of the Co(ii) ion in them. The values of the energy barrier for the magnetic relaxation (Ea) are 5.45-7.74 (), 4.53-9.24 () and 11.48-15.44 cm(-1) (). They compare well with those previously reported for the analogous dca-bridged 2D compound [Co(dca)2(atz)2]n () (Ea = 5.1 cm(-1) under an applied static field of 1000 G), which was the subject of a

  5. Live cell calcium imaging at the single ion hit facility of GSI

    Energy Technology Data Exchange (ETDEWEB)

    Du Guanghua, E-mail: gh_du@impcas.ac.cn [Gesellschaft Fuer Schwerionenforschung (GSI), Planckstr. 1, Darmstadt D-64291 (Germany); E12, Physics Department, James-Franck-Str. 1, Garching D-85748 (Germany); Institute of Modern Physics, Nanchang Rd. 509, Lanzhou 730000 (China); Fischer, Bernd E.; Voss, Kay-Obbe [Gesellschaft Fuer Schwerionenforschung (GSI), Planckstr. 1, Darmstadt D-64291 (Germany)

    2011-10-15

    To study the fast intracellular calcium response after ion irradiation in living mammalian cells, a live cell calcium imaging set-up was constructed at the targeted cell irradiation facility at GSI. This work introduces the live cell calcium imaging system, shows its performance, an example of the ratio-metric calcium measurement and its application to on-line study calcium response to targeted ion irradiation in human cells.

  6. Neutralisation and binding of VHS virus by monovalent antibody fragments

    DEFF Research Database (Denmark)

    Cupit, P.M.; Lorenzen, Niels; Strachan, G.

    2001-01-01

    appeared to recognise a broader range of virus isolates. The variable domains of these two antibodies differ by only four residues (Lorenzen et al., 2000a. Fish Shellfish Immunol. 10, 129-142). To further study the mechanism of neutralisation, Fab fragments as well as a series of recombinant bacterial...... single chain antibody (scAb) fragments were generated from the three anti-VHSV Mabs and their variable domain genes, respectively. Fabs and scAbs derived from the neutralising Mabs were both able to neutralise the VHSV type 1 isolate DK-F1. In addition, a series of scAb fragments were produced using...... the 3F1H10 variable heavy (VH) chain and variable light (V kappa) chain domains but containing, either alone or in dual combination, each of the four different residues present in 3F1A2. The dissociation constants of Mabs 3F1H10 and 3F1A2 and their respective Fab and scAb fragments were measured...

  7. Phase transitions in the two-dimensional single-ion anisotropic Heisenberg model with long-range interactions

    Energy Technology Data Exchange (ETDEWEB)

    Moura, A.R., E-mail: armoura@infis.ufu.br

    2014-11-15

    In the present work, we investigate the effects of long-range interactions on the phase transitions of a two-dimensional Heisenberg model with single-ion anisotropy at zero and finite temperatures. The Hamiltonian is given by H=∑{sub i≠j}J{sub ij}(S{sub i}{sup x}S{sub j}{sup x}+S{sub i}{sup y}S{sub j}{sup y}+λS{sub i}{sup z}S{sub j}{sup z})+D∑{sub i}(S{sub i}{sup z}){sup 2}, where J{sub ij}=−J|r{sub j}−r{sub i}|{sup −p}(p≥3) is a long-range ferromagnetic interaction (J>0), 0≤λ≤1 is an anisotropic constant and D is the single-ion anisotropic constant. It is well-known that the single-ion anisotropy D creates a competition between an ordered state (favored by the exchange interaction) and a disordered state, even at zero temperature. For small values of D, the system has a spontaneous magnetization m{sub z}≠0, while in the large-D phase m{sub z}=0 because a state with 〈S{sup z}〉≠0 is energetically unfavorable. Therefore a phase transition takes a place in some critical value D{sub c} due to quantum fluctuations. For systems with short-range interaction D{sub c}≈6 J (depending of λ constant) but in our model we have found larger values of D due to the higher cost to flip a spin. Since low-dimensional magnetic systems with long range interaction can be ordered at finite temperature, we also have analyzed the thermal phase transitions (similar to the BKT transition). The model has been studied by using a Schwinger boson formalism as well as the self-consistent harmonic approximation (SCHA) and both methods provide according results. - Highlights: • We study the two-dimensional single-ion anisotropic ferromagnetic model with long-range interactions. • We show the quantum phase transition associated with the single-ion anisotropic constant. • We investigate the influence of the power-law exponent in the phase transitions. • We obtain a thermal phase transition similar to the BKT transition.

  8. Cluster-continuum quasichemical theory calculation of the lithium ion solvation in water, acetonitrile and dimethyl sulfoxide: an absolute single-ion solvation free energy scale.

    Science.gov (United States)

    Carvalho, Nathalia F; Pliego, Josefredo R

    2015-10-28

    Absolute single-ion solvation free energy is a very useful property for understanding solution phase chemistry. The real solvation free energy of an ion depends on its interaction with the solvent molecules and on the net potential inside the solute cavity. The tetraphenyl arsonium-tetraphenyl borate (TATB) assumption as well as the cluster-continuum quasichemical theory (CC-QCT) approach for Li(+) solvation allows access to a solvation scale excluding the net potential. We have determined this free energy scale investigating the solvation of the lithium ion in water (H2O), acetonitrile (CH3CN) and dimethyl sulfoxide (DMSO) solvents via the CC-QCT approach. Our calculations at the MP2 and MP4 levels with basis sets up to the QZVPP+diff quality, and including solvation of the clusters and solvent molecules by the dielectric continuum SMD method, predict the solvation free energy of Li(+) as -116.1, -120.6 and -123.6 kcal mol(-1) in H2O, CH3CN and DMSO solvents, respectively (1 mol L(-1) standard state). These values are compatible with the solvation free energy of the proton of -253.4, -253.2 and -261.1 kcal mol(-1) in H2O, CH3CN and DMSO solvents, respectively. Deviations from the experimental TATB scale are only 1.3 kcal mol(-1) in H2O and 1.8 kcal mol(-1) in DMSO solvents. However, in the case of CH3CN, the deviation reaches a value of 9.2 kcal mol(-1). The present study suggests that the experimental TATB scale is inconsistent for CH3CN. A total of 125 values of the solvation free energy of ions in these three solvents were obtained. These new data should be useful for the development of theoretical solvation models.

  9. Ground-state phase diagram of an (S, S') = (1, 2) spin-alternating chain with competing single-ion anisotropies

    Energy Technology Data Exchange (ETDEWEB)

    Tonegawa, T [Department of Mechanical Engineering, Fukui University of Technology, Fukui 910-8505 (Japan); Okamoto, K [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Sakai, T [Japan Atomic Energy Agency (JAEA), Spring-8, Hyogo 679-5148 (Japan); Kaburagi, M, E-mail: tonegawa@ccmails.fukui-ut.ac.j [Graduate School of Intercultural Studies, Kobe University, Kobe 657-8501 (Japan)

    2009-01-01

    Employing various numerical methods, we determine the ground-state phase diagram of an (S, S') = (1, 2) spin-alternating chain with antiferromagnetic nearest-neighboring exchange interactions and uniaxial single-ion anisotropies. The resulting phase diagram consists of eight kinds of phases including two phases which accompany the spontaneous breaking of the translational symmetry and a ferrimagnetic phase in which the ground-state magnetization varies continuously with the uniaxial single-ion anisotropy constants for the S=1 and S =2 spins. The appearance of these three phases is attributed to the competition between the uniaxial single-ion anisotropies of both spins.

  10. Ionic concentration- and pH-dependent electrophoretic mobility as studied by single colloid electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, I; Papadopoulos, P; Kremer, F [Institute for Experimental Physics I (MOP), University of Leipzig, Linnestrasse 5, 04103 Leipzig (Germany); Stober, G, E-mail: friedrich.kremer@physik.uni-leipzig.d [Institute of Atmospheric Physics, University of Rostock, Schlossstrasse 6, 18225 Kuehlungsborn (Germany)

    2010-12-15

    Optical tweezers are employed to measure separately the complex electrophoretic mobility of a single colloid and the complex electroosmotic response of the surrounding medium in a specially designed microfluidic cell. Using the very same colloid both quantities are determined in dependence on the concentration of the aqueous salt solution (10{sup -5}-10{sup -1} mol l{sup -1}), the valence of the ions (K{sup +}, Ca{sup 2+}) and the pH (2.5-8.5). A pronounced effect is observed for all these examined parameters. The dependence on ion concentration agrees qualitatively-for the monovalent case-with the predictions of the standard electrokinetic model.

  11. Interaction of singly and multiply charged ions with a lithium-fluoride surface

    CERN Document Server

    Wirtz, L

    2001-01-01

    Charge transfer between slow ions and an ionic crystal surface still poses a considerable challenge to theory due to the intrinsic many-body character of the system. For the neutralization of multiply charged ions in front of metal surfaces, the Classical Over the Barrier (COB) model is a widely used tool. We present an extension of this model to ionic crystal surfaces where the localization of valence electrons at the anion sites and the lack of cylindrical symmetry of the ion-surface system impede a simple analytical estimate of electron transfer rates. We use a classical trajectory Monte Carlo approach to calculate electron transfer rates for different charge states of the projectile ion. With these rates we perform a Monte Carlo simulation of the neutralization of slow Ne10+ ions in vertical incidence on an LiF surface. Capture of one or several electrons may lead to a local positive charge up of the surface. The projectile dynamics depends on the balance between the repulsion due to this charge and the a...

  12. Amorphization and recrystallization of single-crystalline hydrogen titanate nanowires by N{sup +} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Akshaya K.; Bandyopadyay, Malay K.; Chatterjee, Shyamal, E-mail: shyamal@iitbbs.ac.in [School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar 751007 (India); Facsko, Stefan [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Das, Siddhartha [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2014-06-21

    We report on the phase transformation of hydrogen titanate (H{sub 2}Ti{sub 3}O{sub 7}) nanowires induced by 50 keV N{sup +} ion irradiation at room temperature with fluences of 1 × 10{sup 15} ions/cm{sup 2} and 1 × 10{sup 16} ions/cm{sup 2}, respectively. Using transmission electron microscopy, the internal structure of the ion irradiated nanowires is analyzed. At low fluence, a transformation from crystalline H{sub 2}Ti{sub 3}O{sub 7} to amorphous TiO{sub 2} is observed. However, at higher fluence, a remarkable crystalline-amorphous TiO{sub 2} core-shell structure is formed. At this higher fluence, the recrystallization occurs in the core of the nanowire and the outer layer remains amorphous. The phase transformation and formation of core-shell structure are explained using the thermal spike model, radiation enhanced diffusion, and classical theory of nucleation and growth under non-equilibrium thermodynamics. X-ray photoelectron spectroscopy and Raman scattering reveal further insight into the structure of the nanowires before and after ion irradiation.

  13. EPR and optical absorption studies on Gd{sup 3+} ions in ammonium hydrogen malonate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kripal, Ram, E-mail: ram_kripal2001@rediffmail.co [EPR Laboratory, Department of Physics, University of Allahabad, Allahabad 211002 (India); Mishra, Indrajeet, E-mail: indrajeet_mishra47@rediffmail.co [EPR Laboratory, Department of Physics, University of Allahabad, Allahabad 211002 (India); Department of Physics, D.D.U. Government P.G. College, Saidabad, Allahabad (India)

    2010-01-01

    X-Band electron paramagnetic resonance (EPR) studies of Gd{sup 3+} ions in ammonium hydrogen malonate single crystals have been done at room temperature. Detailed EPR analysis indicates the presence of four physically equivalent but magnetically inequivalent sites. The zero-field splitting parameters and g factor are determined. The Gd{sup 3+} ion is in {sup 8}S state; its levels are split by the action of the crystalline electric field of monoclinic symmetry. The optical absorption spectra of Gd{sup 3+} ions in single crystals of ammonium hydrogen malonate are also recorded at room temperature. The energy levels of the 4f{sup 7} configuration are calculated and compared with those observed experimentally. The values of E{sup 1}=5854+-11, E{sup 2}=31+-0.36, E{sup 3}=592+-3.3 and zeta{sub 4f}=1595+-25 cm{sup -1} are found to give the best over-all agreement between experimentally observed and calculated levels.

  14. Analysis of trace inorganic anions in weak acid salts by single pump cycling-column-switching ion chromatography.

    Science.gov (United States)

    Huang, Zhongping; Ni, Chengzhu; Zhu, Zhuyi; Pan, Zaifa; Wang, Lili; Zhu, Yan

    2015-05-01

    The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts.

  15. Single-ion magnetic anisotropy and isotropic magnetic couplings in the metal-organic framework Fe2(dobdc).

    Science.gov (United States)

    Maurice, Rémi; Verma, Pragya; Zadrozny, Joseph M; Luo, Sijie; Borycz, Joshua; Long, Jeffrey R; Truhlar, Donald G; Gagliardi, Laura

    2013-08-19

    The metal-organic framework Fe2(dobdc) (dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate), often referred to as Fe-MOF-74, possesses many interesting properties such as a high selectivity in olefin/paraffin separations. This compound contains open-shell Fe(II) ions with open coordination sites which may have large single-ion magnetic anisotropies, as well as isotropic couplings between the nearest and next nearest neighbor magnetic sites. To complement a previous analysis of experimental data made by considering only isotropic couplings [Bloch et al. Science 2012, 335, 1606], the magnitude of the main magnetic interactions are here assessed with quantum chemical calculations performed on a finite size cluster. It is shown that the single-ion anisotropy is governed by same-spin spin-orbit interactions (i.e., weak crystal-field regime), and that this effect is not negligible compared to the nearest neighbor isotropic couplings. Additional magnetic data reveal a metamagnetic behavior at low temperature. This effect can be attributed to various microscopic interactions, and the most probable scenarios are discussed.

  16. A Nanophase-Separated, Quasi-Solid-State Polymeric Single-Ion Conductor: Polysulfide Exclusion for Lithium–Sulfur Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jinhong; Song, Jongchan; Lee, Hongkyung; Noh, Hyungjun; Kim, Yun-Jung; Kwon, Sung Hyun; Lee, Seung Geol; Kim, Hee-Tak

    2017-04-19

    Formation of soluble polysulfide (PS), which is a key feature of lithium sulfur (Li–S) batteries, provides a fast redox kinetic based on a liquid–solid mechanism; however, it imposes the critical problem of PS shuttle. Here, we address the dilemma by exploiting a solvent-swollen polymeric single-ion conductor (SPSIC) as the electrolyte medium of the Li–S battery. The SPSIC consisting of a polymeric single-ion conductor and lithium salt-free organic solvents provides Li ion hopping by forming a nanoscale conducting channel and suppresses PS shuttle according to the Donnan exclusion principle when being employed for Li–S batteries. The organic solvents at the interface of the sulfur/carbon composite and SPSIC eliminate the poor interfacial contact and function as a soluble PS reservoir for maintaining the liquid–solid mechanism. Furthermore, the quasi-solid-state SPSIC allows the fabrication of a bipolar-type stack, which promises the realization of a high-voltage and energy-dense Li–S battery.

  17. High-resolution spectroscopy of single Pr$^{3+}$ ions on the $^3$H$_4$-$^1$D$_2$ transition

    CERN Document Server

    Eichhammer, Emanuel; Götzinger, Stephan; Sandoghdar, Vahid

    2015-01-01

    Rare earth ions in crystals exhibit narrow spectral features and hyperfine-split ground states with exceptionally long coherence times. These features make them ideal platforms for quantum information processing in the solid state. Recently, we reported on the first high-resolution spectroscopy of single Pr$^{3+}$ ions in yttrium orthosilicate (YSO) nanocrystals. While in that work we examined the less explored $^3$H$_4$-$^3$P$_0$ transition at a wavelength of 488 nm, here we extend our investigations to the $^3$H$_4$-$^1$D$_2$ transition at 606 nm. In addition, we present measurements of the second-order autocorrelation function, fluorescence lifetime, and emission spectra of single ions as well as their polarization dependencies on both transitions; these data were not within the reach of the first experiments reported earlier. Furthermore, we show that by a proper choice of the crystallite, one can obtain narrower spectral lines and, thus, resolve the hyperfine levels of the excited state. We expect our re...

  18. Single-ion triblock copolymer electrolytes based on poly(ethylene oxide) and methacrylic sulfonamide blocks for lithium metal batteries

    Science.gov (United States)

    Porcarelli, Luca; Aboudzadeh, M. Ali; Rubatat, Laurent; Nair, Jijeesh R.; Shaplov, Alexander S.; Gerbaldi, Claudio; Mecerreyes, David

    2017-10-01

    Single-ion conducting polymer electrolytes represent the ideal solution to reduce concentration polarization in lithium metal batteries (LMBs). This paper reports on the synthesis and characterization of single-ion ABA triblock copolymer electrolytes comprising PEO and poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) blocks, poly(LiMTFSI). Block copolymers are prepared by reversible addition-fragmentation chain transfer polymerization, showing low glass transition temperature (-55 to 7 °C) and degree of crystallinity (51-0%). Comparatively high values of ionic conductivity are obtained (up to ≈ 10-4 S cm-1 at 70 °C), combined with a lithium-ion transference number close to unity (tLi+ ≈ 0.91) and a 4 V electrochemical stability window. In addition to these promising features, solid polymer electrolytes are successfully tested in lithium metal cells at 70 °C providing long lifetime up to 300 cycles, and stable charge/discharge cycling at C/2 (≈100 mAh g-1).

  19. Numerical simulation of thermal behavior of lithium-ion secondary batteries using the enhanced single particle model

    Science.gov (United States)

    Baba, Naoki; Yoshida, Hiroaki; Nagaoka, Makoto; Okuda, Chikaaki; Kawauchi, Shigehiro

    2014-04-01

    To understand the thermal behavior of lithium-ion secondary batteries, distributed information related to local heat generation across the entire electrode plane, which is caused by the electrochemical reaction that results from lithium-ion intercalation or deintercalation, is required. To accomplish this, we first developed an enhanced single particle (ESP) model for lithium-ion batteries that provides a cost effective, timely, and accurate method for estimating the local heat generation rates without excessive computation costs. This model accounts for all the physical processes, including the solution phase limitation. Next, a two-way electrochemical-thermal coupled simulation method was established. In this method, the three dimensional (3D) thermal solver is coupled with the quasi-3D porous electrode solver that is applied to the unrolled plane of spirally wound electrodes, which allows both thermal and electrochemical behaviors to be reproduced simultaneously at every computational time-step. The quasi-3D porous electrode solver implements the ESP model. This two-way coupled simulation method was applied to a thermal behavior analysis of 18650-type lithium-ion cells where it was found that temperature estimates of the electrode interior and on the cell can wall obtained via the ESP model were in good agreement with actual experimental measurements.

  20. Atomic parity violation in one single trapped and laser cooled radium ion: a probe of electroweak running

    Energy Technology Data Exchange (ETDEWEB)

    Giri, G.S.; Boell, O.; Jungmann, K.; Sahoo, B.K.; Timmermans, R.G.E.; Versolato, O.O.; Wansbeek, L.W.; Willmann, L. [KVI, University of Groningen (Netherlands)

    2009-07-01

    One single-trapped and laser cooled radium ion is an ideal candidate to investigate atomic parity non-conservation (APNC). APNC can serve as a low energy test of the Standard Model of particle physics. We aim for a precision measurement of the electroweak mixing angle, by probing the differential light shift of the 7S and 6D Zeeman sublevels. This shift is caused by the interaction of the ion with an off-resonant laser light field. With precision RF spectroscopy and subsequent electron shelving, the differential splitting can be determined to sub-Hertz accuracy. Recent calculations show that Ra{sup +} is a superior candidate for probing APNC. With an almost identical set-up and using the electron shelving technique, ultra-narrow transitions in this ion can be exploited for an all optical, high stability frequency standard clock. We have succeeded in the production and subsequent slowing down of radium isotopes around {sup 213}Ra. Further progress has been made in the development of ion traps and the necessary high precision optical laboratory. Laser spectroscopy of Ra{sup +} and the first ever trapping of this particle are being prepared.

  1. Obtaining Spheroplasts of Armored Dinoflagellates and First Single-Channel Recordings of Their Ion Channels Using Patch-Clamping

    Directory of Open Access Journals (Sweden)

    Ilya Pozdnyakov

    2014-09-01

    Full Text Available Ion channels are tightly involved in various aspects of cell physiology, including cell signaling, proliferation, motility, endo- and exo-cytosis. They may be involved in toxin production and release by marine dinoflagellates, as well as harmful algal bloom proliferation. So far, the patch-clamp technique, which is the most powerful method to study the activity of ion channels, has not been applied to dinoflagellate cells, due to their complex cellulose-containing cell coverings. In this paper, we describe a new approach to overcome this problem, based on the preparation of spheroplasts from armored bloom-forming dinoflagellate Prorocentrum minimum. We treated the cells of P. minimum with a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB, and found out that it could also induce ecdysis and arrest cell shape maintenance in these microalgae. Treatment with 100–250 µM DCB led to an acceptable 10% yield of P. minimum spheroplasts and was independent of the incubation time in the range of 1–5 days. We show that such spheroplasts are suitable for patch-clamping in the cell-attached mode and can form 1–10 GOhm patch contact with a glass micropipette, allowing recording of ion channel activity. The first single-channel recordings of dinoflagellate ion channels are presented.

  2. Obtaining spheroplasts of armored dinoflagellates and first single-channel recordings of their ion channels using patch-clamping.

    Science.gov (United States)

    Pozdnyakov, Ilya; Matantseva, Olga; Negulyaev, Yuri; Skarlato, Sergei

    2014-09-05

    Ion channels are tightly involved in various aspects of cell physiology, including cell signaling, proliferation, motility, endo- and exo-cytosis. They may be involved in toxin production and release by marine dinoflagellates, as well as harmful algal bloom proliferation. So far, the patch-clamp technique, which is the most powerful method to study the activity of ion channels, has not been applied to dinoflagellate cells, due to their complex cellulose-containing cell coverings. In this paper, we describe a new approach to overcome this problem, based on the preparation of spheroplasts from armored bloom-forming dinoflagellate Prorocentrum minimum. We treated the cells of P. minimum with a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), and found out that it could also induce ecdysis and arrest cell shape maintenance in these microalgae. Treatment with 100-250 µM DCB led to an acceptable 10% yield of P. minimum spheroplasts and was independent of the incubation time in the range of 1-5 days. We show that such spheroplasts are suitable for patch-clamping in the cell-attached mode and can form 1-10 GOhm patch contact with a glass micropipette, allowing recording of ion channel activity. The first single-channel recordings of dinoflagellate ion channels are presented.

  3. Quantum interferences in single ionization of He by highly charged dressed-ions impact

    Energy Technology Data Exchange (ETDEWEB)

    Monti, J M; Rivarola, R D [Instituto de Fisica Rosario (CONICET-UNR) and Facultad de Ciencias Exactas, IngenierIa y Agrimensura, Universidad Nacional de Rosario, Pellegrini 250, 2000 Rosario (Argentina); Fainstein, P D, E-mail: rivarola@fceia.unr.edu.ar [Comision Nacional de EnergIa Atomica, Centro Atomico Bariloche, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina)

    2011-06-15

    Ionization of He targets by impact of partially stripped ions is investigated by means of an extension to the continuum distorted wave-eikonal initial state model with a particular representation of the projectile potential. Structures appearing superimposed on the binary encounter peak are interpreted in terms of coherent interference of short- and long-range contributions of the perturbative projectile potential. The case of 600 keV u{sup -1}Au{sup 11+} ions impinging on He is presented and discussed.

  4. Quantum Dynamics of a Single Trapped Ion Interacting with Standing Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    LI Fei; HAI Wen-Hua; CHONG Gui-Shu; XIE Qiong-Tao

    2004-01-01

    A classically chaotic system consisting of a Paul trapped ion and a sequences of standing laser pulses is treated quantum-mechanically. Under the circumstance of time-dependence, we derive the transition probability from the ion's motional state n to n', and find, in the first-order approximation, the classically chaotic character disappears.Theoretical analysis and numerical calculations show that by regulating the phase parameter φ we can control the transition probability. When φ reaches some specific values, the transition from the state n to n' is forbidden and, for some laser periods, resonance occurs, which leads to the corresponding transitions between different motional states.

  5. Neutralizing antibody responses in macaques induced by human immunodeficiency virus type 1 monovalent or trivalent envelope glycoproteins.

    Directory of Open Access Journals (Sweden)

    Gerald V Quinnan

    Full Text Available A major goal of efforts to develop a vaccine to prevent HIV-1 infection is induction of broadly cross-reactive neutralizing antibodies (bcnAb. In previous studies we have demonstrated induction of neutralizing antibodies that did cross-react among multiple primary and laboratory strains of HIV-1, but neutralized with limited potency. In the present study we tested the hypothesis that immunization with multiple HIV-1 envelope glycoproteins (Envs would result in a more potent and cross-reactive neutralizing response. One Env, CM243(N610Q, was selected on the basis of studies of the effects of single and multiple mutations of the four gp41 glycosylation sites. The other two Envs included R2 (subtype B and 14/00/4 (subtype F, both of which were obtained from donors with bcnAb. Rhesus monkeys were immunized using a prime boost regimen as in previous studies. Individual groups of monkeys were immunized with either one of the three Envs or all three. The single N610Q and N615Q mutations of CM243 Env did not disrupt protein secretion, processing into, or reactivity with mAbs, unlike other single or multiple deglycosylation mutations. In rabbit studies the N610Q mutation alone or in combination was associated with an enhanced neutralizing response against homologous and heterologous subtype E viruses. In the subsequent monkey study the response induced by the R2 Env regimen was equivalent to the trivalent regimen and superior to the other monovalent regimens against the virus panel used for testing. The 14/00/4 Env induced responses superior to CM243(N610Q. The results indicate that elimination of the glycosylation site near the gp41 loop results in enhanced immunogenicity, but that immunization of monkeys with these three distinct Envs was not more immunogenic than with one.

  6. Electron Spin Resonance Study of Organic Interfaces in Ion Gel-Gated Rubrene Single-Crystal Transistors

    Science.gov (United States)

    Takahashi, Yuki; Tsuji, Masaki; Yomogida, Yohei; Takenobu, Taishi; Iwasa, Yoshihiro; Marumoto, Kazuhiro

    2013-04-01

    Organic interfaces of rubrene single crystals (RSCs) in ion gel-gated electric double-layer transistors (EDLTs) were investigated by electron spin resonance (ESR). The EDLTs were fabricated by laminating ion-gel films onto RSCs. Clear ESR signals due to field-injected holes in RSCs were successfully observed at low gate voltages, showing a high spin concentration due to the high capacitance of EDLTs. The analyses of anisotropic ESR signals and its gate-voltage dependence show that the bulk molecular orientation at RSCs' interfaces is preserved without forming deep trapping levels, which demonstrate that organic interfaces in RSC-EDLTs are clean and undamaged under a strong electric field in EDLTs.

  7. Single-crystalline LiFePO4 nanosheets for high-rate Li-ion batteries.

    Science.gov (United States)

    Zhao, Yu; Peng, Lele; Liu, Borui; Yu, Guihua

    2014-05-14

    The lithiation/delithiation in LiFePO4 is highly anisotropic with lithium-ion diffusion being mainly confined to channels along the b-axis. Controlling the orientation of LiFePO4 crystals therefore plays an important role for efficient mass transport within this material. We report here the preparation of single crystalline LiFePO4 nanosheets with a large percentage of highly oriented {010} facets, which provide the highest pore density for lithium-ion insertion/extraction. The LiFePO4 nanosheets show a high specific capacity at low charge/discharge rates and retain significant capacities at high C-rates, which may benefit the development of lithium batteries with both favorable energy and power density.

  8. Large area superconducting YBa 2Cu 3O 7-x films grown by single target ion beam sputtering

    Science.gov (United States)

    Gauzzi, Andrea; Lucía, Maria L.; Kellett, Bruce J.; James, Jonathan H.; Pavuna, Davor

    1991-10-01

    We have demonstrated, by using a simple single YBa 2Cu 3O 7- x target ion beam system that, with a sufficiently low power ion beam, preferential sputtering is avoided and high-quality YBa 2Cu 3O 7- x films are deposited over areas larger than ≈ 30 cm 2 in a reproducible way. As-deposited films on SrTiO 3 are 50-100 nmthick, c-oriented and show the following reproducible electrical properties (within the given variations): Tc0 =90±0.5 K, transitions widths less than 1 K, j inc(77 K)=1.0-1.2× 10 6 A cm -2, ϱ(300 K)=300±50μΩ cm, ϱ(300 K)/ ϱ(100 K)=2.9±0.1. The extrapolated residual resistivity ϱ res(O K) is between 0 and 5% of ϱ(300 K).

  9. Internal Friction Due to Localized Relaxation around Y-ions in Single Crystal Yttria-Stabilized Zirconia

    Science.gov (United States)

    Ohta, Michihiro; Kirimoto, Kenta; Nobugai, Kohji; Wigmore, J. Keith; Miyasato, Tatsuro

    2001-09-01

    The internal friction in single crystal yttria-stabilized zirconia (YSZ) doped with 9.5 mol% Y2O3 was measured for longitudinal sound waves in the frequency range from 10 Hz to 800 Hz using a vibrating reed technique. In the temperature range from 300 K to 700 K, observations of internal friction reveal two closely overlapping absorption peaks, confirming the existence of two relaxation modes in YSZ@. One of the peaks is due to diffusion relaxation, which is known to be responsible for long-range transport of O-ions. The second peak shows clearly the existence of localized relaxation, which is attributed to bound oxygen vacancies within the local structure which is formed around an Y-ion due to symmetry breaking. The absorption peak caused by the localized relaxation exhibits anisotropy resulting from the asymmetric local structure, and the strength of this peak changes with temperature reflecting the number of bound oxygen vacancies.

  10. Quantum Logic Operation with Single Trapped Ion Without Limitation of Lamb-Dicke Parameter

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rong; ZHU Shi-Qun

    2003-01-01

    By applying the nonlinear interaction between internal and external degrees of a trapped ion with theassistance of two pairs or three pairs of laser beams that are perpendicular to each other, the realization of quantumlogic operation without the limitation on the Lamb-Dicke parameter can be achieved when the lasers are tuned to thecarrier.

  11. Fluorescence-based high-throughput functional profiling of ligand-gated ion channels at the level of single cells.

    Directory of Open Access Journals (Sweden)

    Sahil Talwar

    Full Text Available Ion channels are involved in many physiological processes and are attractive targets for therapeutic intervention. Their functional properties vary according to their subunit composition, which in turn varies in a developmental and tissue-specific manner and as a consequence of pathophysiological events. Understanding this diversity requires functional analysis of ion channel properties in large numbers of individual cells. Functional characterisation of ligand-gated channels involves quantitating agonist and drug dose-response relationships using electrophysiological or fluorescence-based techniques. Electrophysiology is limited by low throughput and high-throughput fluorescence-based functional evaluation generally does not enable the characterization of the functional properties of each individual cell. Here we describe a fluorescence-based assay that characterizes functional channel properties at single cell resolution in high throughput mode. It is based on progressive receptor activation and iterative fluorescence imaging and delivers >100 dose-responses in a single well of a 384-well plate, using α1-3 homomeric and αβ heteromeric glycine receptor (GlyR chloride channels as a model system. We applied this assay with transiently transfected HEK293 cells co-expressing halide-sensitive yellow fluorescent protein and different GlyR subunit combinations. Glycine EC50 values of different GlyR isoforms were highly correlated with published electrophysiological data and confirm previously reported pharmacological profiles for the GlyR inhibitors, picrotoxin, strychnine and lindane. We show that inter and intra well variability is low and that clustering of functional phenotypes permits identification of drugs with subunit-specific pharmacological profiles. As this method dramatically improves the efficiency with which ion channel populations can be characterized in the context of cellular heterogeneity, it should facilitate systems

  12. A new strategy to stabilize oxytocin in aqueous solutions : I. The effects of divalent metal ions and citrate buffer

    NARCIS (Netherlands)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J. M.; Hinrichs, Wouter L. J.; Frijlink, Henderik W.

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The

  13. A new strategy to stabilize oxytocin in aqueous solutions : I. The effects of divalent metal ions and citrate buffer

    NARCIS (Netherlands)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J. M.; Hinrichs, Wouter L. J.; Frijlink, Henderik W.

    2011-01-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The effec

  14. Single and double charge exchange processes with low energy multicharged ions

    Energy Technology Data Exchange (ETDEWEB)

    Vernhet, D.; Chetioui, A.; Wohrer, K.; Politis, M.F.; Touati, A.; Rozet, J.P.; Bouisset, P.; Stephan, C.

    1987-04-01

    An original method is presented for extracting information on single and double capture processes in low velocity collisions with bare and one-electron projectiles. Experimental data are reported for P(l) distributions in single capture and for the percentage of double capture with respect to the single capture and for the percentage of double capture with respect to the single capture in 10q keV Ne/sup 9 +/ -> H/sub 2/ and Al/sup 13 +/ -> He systems (upsilon approx. = 0.4 a.u.). The preferential n state populated by double capture (after autoionization) is also deduced.

  15. Radiation-induced effects in MgO single crystal by 200 keV and 1 MeV Ni ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ryohei; Nakai, Yoshihiro; Hamaguchi, Dai [Kyoto Inst. of Tech. (Japan)] [and others

    1997-03-01

    MgO(100) single crystals were implanted with 1.0 MeV and 200 keV Ni ions between 10{sup 15} and 10{sup 17} ions/cm{sup 2} at room temperature. Before and after thermal annealing the radiation damage and the lattice location of implanted Ni ions were analyzed by using Rutherford backscattering spectrometry with channeling and optical absorption measurements. For 1.0 MeV Ni ions, the disorder of Mg atoms increased slowly with ion dose near surface region, while it increased sharply and saturated with ion dose from 2x10{sup 16} ions/cm{sup 2} near ion range. The radiation damage was recovered and implanted Ni ions diffused to the whole of crystal and occupied substitutional positions after 1400degC annealing. For 200 keV Ni ions, the disorder of Mg atoms increased with dose near ion range and had a maximum at about 5x10{sup 16} ions/cm{sup 2}. This tendency agrees with the behavior of color centers obtained from optical measurements. For thermal annealing the radiation damage did not change during 500degC annealing, but the aggregate centers appeared after 300degC annealing. (author)

  16. Mixed polyvalent-monovalent metal coating for carbon-graphite fibers

    Science.gov (United States)

    Harper-Tervet, J.; Tervet, F. W.; Humphrey, M. F. (Inventor)

    1982-01-01

    An improved coating of gasification catalyst for carbon-graphite fibers is provided comprising a mixture of a polyvalent metal such as calcium and a monovalent metal such as lithium. The addition of lithium provides a lighter coating and a more flexible coating when applied to a coating of a carboxyl containing resin such as polyacrylic acid since it reduces the crosslink density. Furthermore, the presence of lithium provides a glass-like substance during combustion which holds the fiber together resulting in slow, even combustion with much reduced evolution of conductive fragments. The coated fibers are utilized as fiber reinforcement for composites.

  17. Performance of single chamber biocatalyzed electrolysis with different types of ion exchange membranes

    NARCIS (Netherlands)

    Rozendal, R.A.; Hamelers, H.V.M.; Molenkamp, R.J.; Buisman, C.J.N.

    2007-01-01

    In this paper hydrogen production through biocatalyzed electrolysis was studied for the first time in a single chamber configuration. Single chamber biocatalyzed electrolysis was tested in two configurations: (i) with a cation exchange membrane (CEM) and (ii) with an anion exchange membrane (AEM). B

  18. State-Selective and Total Single-Capture Cross Sections for Fast Collisions of Multiply Charged Ions with Helium Atoms

    Science.gov (United States)

    Mančev, Ivan; Milojević, Nenad; Belkić, Dževad

    2013-11-01

    The four-body boundary corrected first Born approximation (CB1-4B) is used to calculate the single electron capture cross sections for collisions between fully stripped ions (He2+, Be4+, B5+ and C6+) and helium target at intermediate and high impact energies. The main goal of this study is to assess the usefulness of the CB1-4B method at intermediate and high impact energies for these collisions. Detailed comparisons with the measurements are carried out and the obtained theoretical cross sections are in reasonable agreement with the available experimental data.

  19. Optical Properties of Amorphous AlN Thin Films on Glass and Silicon Substrates Grown by Single Ion Beam Sputtering

    Science.gov (United States)

    Hajakbari, Fatemeh; Mojtahedzadeh Larijani, Majid; Ghoranneviss, Mahmood; Aslaninejad, Morteza; Hojabri, Alireza

    2010-09-01

    The structural and optical properties of aluminum nitride (AlN) films deposited on glass and silicon substrates by single ion beam sputtering technique have been investigated. The X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) study revealed the formation of the amorphous phase of AlN. The optical characteristics of films, such as refractive index, extinction coefficient, and average thickness, were calculated by Swanepoel's method using transmittance measurements. The refractive index and average roughness values of the films increased with film thickness. Moreover, it was found that thickness augmentation leads to a decrease in optical band gap energy calculated using Tauc's relation.

  20. Electron spin resonance study of the single-ion anisotropy in the pyrochlore antiferromagnet Gd2Sn2O7

    Science.gov (United States)

    Glazkov, V. N.; Smirnov, A. I.; Sanchez, J. P.; Forget, A.; Colson, D.; Bonville, P.

    2006-02-01

    Single-ion anisotropy is of importance for the magnetic ordering of the frustrated pyrochlore antiferromagnets Gd2Ti2O7 and Gd2Sn2O7. The anisotropy parameters for Gd2Sn2O7 were measured using the electron spin resonance technique. The anisotropy was found to be of the easy plane type, with the main constant D = 140 mK. This value is 35% smaller than the value of the corresponding anisotropy constant of the related compound Gd2Ti2O7.

  1. A trimetallic strategy towards ZnDyCr and ZnDyCo single-ion magnets.

    Science.gov (United States)

    Hu, Kong-Qiu; Jiang, Xiang; Wu, Shu-Qi; Liu, Cai-Ming; Cui, Ai-Li; Kou, Hui-Zhong

    2015-09-21

    Two cyano- and phenoxo-bridged octanuclear complexes ZnDyCo (complex ) and ZnDyCr (complex ) with diamagnetic Zn(ii) and Co(iii) are reported. Dy(iii) is surrounded by nine oxygen atoms of two [Zn(Me2valpn)] (Me2valpn(2-) = dianion of N,N'-2,2-dimethylpropylenebis(3-methoxysalicylideneimine)) and one water molecule. Magnetic studies reveal that both exhibit single-ion magnet (SIM) behavior with the energy barrier of 85.9 K for complex and 100.9 K for complex .

  2. Integration of biological ion channels onto optically addressable micro-fluidic electrode arrays for single molecule characterization.

    Energy Technology Data Exchange (ETDEWEB)

    Brozik, Susan Marie; Frink, Laura J. Douglas; Bachand, George David; Keller, David J. (University of New Mexico, Albuquerque, NM); Patrick, Elizabeth L.; Marshall, Jason A. (University of New Mexico, Albuquerque, NM); Ortiz, Theodore P. (University of New Mexico, Albuquerque, NM); Meyer, Lauren A. (University of New Mexico, Albuquerque, NM); Davis, Ryan W. (University of New Mexico, Albuquerque, NM); Brozik, James A. (University of New Mexico, Albuquerque, NM); Flemming, Jeb Hunter

    2004-12-01

    The challenge of modeling the organization and function of biological membranes on a solid support has received considerable attention in recent years, primarily driven by potential applications in biosensor design. Affinity-based biosensors show great promise for extremely sensitive detection of BW agents and toxins. Receptor molecules have been successfully incorporated into phospholipid bilayers supported on sensing platforms. However, a collective body of data detailing a mechanistic understanding of membrane processes involved in receptor-substrate interactions and the competition between localized perturbations and delocalized responses resulting in reorganization of transmembrane protein structure, has yet to be produced. This report describes a systematic procedure to develop detailed correlation between (recognition-induced) protein restructuring and function of a ligand gated ion channel by combining single molecule fluorescence spectroscopy and single channel current recordings. This document is divided into three sections: (1) reported are the thermodynamics and diffusion properties of gramicidin using single molecule fluorescence imaging and (2) preliminary work on the 5HT{sub 3} serotonin receptor. Thirdly, we describe the design and fabrication of a miniaturized platform using the concepts of these two technologies (spectroscopic and single channel electrochemical techniques) for single molecule analysis, with a longer term goal of using the physical and electronic changes caused by a specific molecular recognition event as a transduction pathway in affinity based biosensors for biotoxin detection.

  3. Evidence for charge exchange effects in electronic excitations in Al by slow singly charged He ions

    Energy Technology Data Exchange (ETDEWEB)

    Riccardi, P., E-mail: Pierfrancesco.riccardi@fis.unical.it [Dipartimento di Fisica, Università della Calabria and INFN Gruppo collegato di Cosenza, Via P. Bucci cubo 31C, 87036 – Arcavacata di Rende, Cosenza (Italy); Sindona, A. [Dipartimento di Fisica, Università della Calabria and INFN Gruppo collegato di Cosenza, Via P. Bucci cubo 31C, 87036 – Arcavacata di Rende, Cosenza (Italy); Dukes, C.A. [Laboratory for Astrophysics and Surface Physics, Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2016-09-01

    We report on experiments of secondary electron emission in the interaction of helium ions with aluminum surfaces. Comparison between the electron emission induced by the impact of {sup 3}He{sup +} and {sup 4}He{sup +} on Al illustrates similarities and differences between the two projectiles. The intensity of emission shows the same dependence on velocity for the two isotopes, showing that KEE yields for helium ions impact on Al are dominated by direct excitation of valence electrons and not by electron promotion. Electron promotion and charge transfer processes are unambiguously identified by the observation of Auger electron emission from Al, at energies below the excitation threshold of Al–Al collisions, indicating energy losses for the projectiles higher than those commonly considered.

  4. Blistering and cracking of LiTaO{sub 3} single crystal under helium ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Changdong; Lu, Fei; Ma, Yujie [Shandong University, School of Information Science and Engineering, Jinan, Shandong (China)

    2014-11-29

    Blistering and cracking in LiTaO{sub 3} surface are investigated after 200-keV helium ion implantation and subsequent post-implantation annealing. Rutherford backscattering/channeling is used to examine the lattice damage caused by ion implantation. Blistering is observed through optical microscopy in a dynamic heating process. Atomic force microscopy and scanning electron microscopy measurements are used to detect the LiTaO{sub 3} surface morphology. Experimental results show that blistering and flaking are dependent on implantation fluence, beam current, and also annealing temperature. We speculate that the surface cracking of He{sup +}-implanted LiTaO{sub 3} results from the implantation-induced stress and compression. (orig.)

  5. Exact Solution of Quantum Dynamics of a Cantilever Coupling to a Single Trapped Ultracold Ion

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; FENG Mang; WANG Ke-Lin

    2007-01-01

    The quantum behavior of a precooled cantilever can be probed highly efficiently by electrostatically coupling to a trapped ultracold ion, in which a fast cooling of the cantilever down to the ground vibrational state is possible.Within a simple model with an ultracold ion coupled to a cantilever with only few vibrational quanta, we solve the dynamics of the coupling system by a squeezed-state expansion technique, and can in principle obtain the exact solution of the time-evolution of the coupling system in the absence of the rotating-wave approximation. Comparing to the treatment under the rotating-wave approximation, we present a more accurate description of the quantum behavior of the cantilever.

  6. Effects of Metal Ions on Conductivity and Structure of Single DNA Molecule in Different Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Dong Ruixin

    2010-01-01

    Full Text Available Abstract We design a novel nano-gap electrode to measure the current of DNA molecule, by which the current–voltage characteristics of individual native DNA, Ag-DNA and Ni-DNA molecules are obtained, respectively. The results show that the voltage gap of Ag- and Ni-DNA is higher than that of native DNA, and the conductance is lower than native DNA in neutral environment. The structure transition from B- to Z-DNA is observed in the presence of high concentrations of nickel ions and Ag-DNA appears chaos state by STM image and U-V spectra characterization. But in alkaline environment, the conductance of Ni-DNA rises and the voltage gap decreases with the increasing of nickel ion concentration denotes that the conductive ability of Ni-DNA is higher than that of native DNA.

  7. Quantum Dynamics of a Single Trapped Ion Interacting with Standing Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    LIFei; HAIWen-Hua; CHONGGui-Shu; XIEQiong-Tao

    2004-01-01

    A classically chaotic system consisting of a Paul trapped ion and a sequences of standing laser pulses is treated quantum-mechanically. Under the circumstance of time-dependence, we derive the transition probability from the ion's motional state n to n', and find, in the first-order approximation, the classically chaotic character disappears.Theoretical analysis and numerical calculations show that by regulating the phase parameter Ф we can control thetransition probability. When Ф reaches some specific values, the transition from the state n to n' is forbidden and, for some laser periods, resonance occurs, which leads to the corresponding transitions between different motional states.The time-evolution of an initial motional state |ψz) just over one period is also studied in detail.

  8. Hyperfine-interaction-driven suppression of quantum tunneling at zero field in a holmium(III) single-ion magnet

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yan-Cong; Liu, Jun-Liang; Chen, Xiao-Ming; Tong, Ming-Liang [Key Lab. of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen Univ., Guangzhou (China); Wernsdorfer, Wolfgang [Institut Neel, CNRS and Universite Joseph Fournier, Grenoble (France); Institute of Nanotechnology, Karlsruhe Institute of Technology (Germany); Physikalisches Institut, Karlsruhe Institute of Technology (Germany); Liu, Dan; Chibotaru, Liviu F. [Theory of Nanomaterials Group and INPAC-Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven (Belgium)

    2017-04-24

    An extremely rare non-Kramers holmium(III) single-ion magnet (SIM) is reported to be stabilized in the pentagonal-bipyramidal geometry by a phosphine oxide with a high energy barrier of 237(4) cm{sup -1}. The suppression of the quantum tunneling of magnetization (QTM) at zero field and the hyperfine structures originating from field-induced QTMs can be observed even from the field-dependent alternating-current magnetic susceptibility in addition to single-crystal hysteresis loops. These dramatic dynamics were attributed to the combination of the favorable crystal-field environment and the hyperfine interactions arising from {sup 165}Ho (I=7/2) with a natural abundance of 100 %. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Fabrication of single-crystal silicon nanotubes with sub-10 nm walls using cryogenic inductively coupled plasma reactive ion etching.

    Science.gov (United States)

    Li, Zhiqin; Chen, Yiqin; Zhu, Xupeng; Zheng, Mengjie; Dong, Fengliang; Chen, Peipei; Xu, Lihua; Chu, Weiguo; Duan, Huigao

    2016-09-09

    Single-crystal silicon nanostructures have attracted much attention in recent years due in part to their unique optical properties. In this work, we demonstrate direct fabrication of single-crystal silicon nanotubes with sub-10 nm walls which show low reflectivity. The fabrication was based on a cryogenic inductively coupled plasma reactive ion etching process using high-resolution hydrogen silsesquioxane nanostructures as the hard mask. Two main etching parameters including substrate low-frequency power and SF6/O2 flow rate ratio were investigated to determine the etching mechanism in the process. With optimized etching parameters, high-aspect-ratio silicon nanotubes with smooth and vertical sub-10 nm walls were fabricated. Compared to commonly-used antireflection silicon nanopillars with the same feature size, the densely packed silicon nanotubes possessed a lower reflectivity, implying possible potential applications of silicon nanotubes in photovoltaics.

  10. Room temperature fluorescence and phosphorescence study on the interactions of iodide ions with single tryptophan containing serum albumins

    Science.gov (United States)

    Gałęcki, Krystian; Kowalska-Baron, Agnieszka

    2016-12-01

    In this study, the influence of heavy-atom perturbation, induced by the addition of iodide ions, on the fluorescence and phosphorescence decay parameters of some single tryptophan containing serum albumins isolated from: human (HSA), equine (ESA) and leporine (LSA) has been studied. The obtained results indicated that, there exist two distinct conformations of the proteins with different exposure to the quencher. In addition, the Stern-Volmer plots indicated saturation of iodide ions in the binding region. Therefore, to determine quenching parameter, we proposed alternative quenching model and we have performed a global analysis of each conformer to define the effect of iodide ions in the cavity by determining the value of the association constant. The possible quenching mechanism may be based on long-range through-space interactions between the buried chromophore and quencher in the aqueous phase. The discrepancies of the decay parameters between the albumins studied may be related with the accumulation of positive charge at the main and the back entrance to the Drug Site 1 where tryptophan residue is located.

  11. Single crystal silicon carbide detector of emitted ions and soft x rays from power laser-generated plasmas

    Science.gov (United States)

    Torrisi, L.; Foti, G.; Giuffrida, L.; Puglisi, D.; Wolowski, J.; Badziak, J.; Parys, P.; Rosinski, M.; Margarone, D.; Krasa, J.; Velyhan, A.; Ullschmied, U.

    2009-06-01

    A single-crystal silicon carbide (SiC) detector was used for measurements of soft x rays, electrons, and ion emission from laser-generated plasma obtained with the use of the Prague Asterix Laser System (PALS) at intensities of the order of 1016 W/cm2 and pulse duration of 300 ps. Measurements were performed by varying the laser intensity and the nature of the irradiated target. The spectra obtained by using the SiC detector show not only the photopeak due to UV and soft x-ray detection, but also various peaks due to the detection of energetic charged particles. Time-of-flight technique was employed to determine the ion kinetic energy of particles emitted from the plasma and to perform a comparison between SiC and traditional ion collectors. The detector was also employed by inserting absorber films of different thickness in front of the SiC surface in order to determine, as a first approximation, the mean energy of the soft x-ray emission from the plasma.

  12. Surgical cardiac denervation therapy for treatment of congenital ion channelopathies in pediatric patients: a contemporary, single institutional experience.

    Science.gov (United States)

    Costello, John P; Wilson, Jennifer K; Louis, Clauden; Peer, Syed M; Zurakowski, David; Nadler, Evan P; Qureshi, Faisal G; Jonas, Richard A; Greene, E Anne; Berul, Charles I; Moak, Jeffrey P; Nath, Dilip S

    2015-01-01

    Congenital ion channel disorders, including congenital long QT syndrome (LQTS), cause significant morbidity in pediatric patients. When medication therapy does not control symptoms or arrhythmias, more invasive treatment strategies may be necessary. This study examines our institution's clinical experience with surgical cardiac denervation therapy for management of these arrhythmogenic disorders in children. An institutional review board-approved retrospective review identified ten pediatric patients with congenital ion channelopathies who underwent surgical cardiac denervation therapy at a single institution between May 2011 and April 2014. Eight patients had a diagnosis of congenital LQTS, two patients were diagnosed with catecholaminergic polymorphic ventricular tachycardia (CPVT). All patients underwent sympathectomy and partial stellate ganglionectomy via video-assisted thoracoscopic surgery (VATS). Six of the ten patients had documented ventricular arrhythmias preoperatively, and 70% of the patients had preoperative syncope. The corrected QT interval decreased in 75% of patients with LQTS following sympathectomy. Postoperative arrhythmogenic symptoms were absent in 88% of congenital LQTS patients, but both patients with CPVT continued to have symptoms throughout the duration of follow-up. All patients were alive after a median follow-up period of 10 months. Surgical cardiac denervation therapy via VATS is a useful treatment strategy for congenital LQTS patients who fail medical management, and its potential benefit in the management of CPVT is unclear. A prospective comparison of the efficacy of surgical cardiac denervation therapy and implantable cardioverter-defibrillator use in congenital ion channelopathies is timely and crucial. © The Author(s) 2014.

  13. Enzymatically mediated bioprecipitation of heavy metals from industrial wastes and single ion solutions by mammalian alkaline phosphatase.

    Science.gov (United States)

    Chaudhuri, Gouri; Shah, Gaurav A; Dey, Pritam; S, Ganesh; Venu-Babu, P; Thilagaraj, W Richard

    2013-01-01

    The study was aimed at investigating the potential use of calf intestinal alkaline phosphatase (CIAP) enzyme in the removal of heavy metals (Cd(2+), Ni(2+), Co(2+) and Cr(3+/6+)) from single ion solutions as well as tannery and electroplating effluents. CIAP mediated bioremediation (white biotechnology) is a novel technique that is eco-friendly and cost effective unlike the conventional chemical technologies. Typical reactions containing the enzyme (CIAP) and p-nitrophenyl phosphate (pNPP) as substrate in Tris-HCl buffer (pH 8 and 11) and either single ion metal solutions (250 ppm and 1000 ppm) or effluents from tannery or electroplating industry were incubated at 37°C for 30 min, 60 min and 120 min. The inorganic phosphate (P(i)) generated due to catalytic breakdown of pNPP complexes free metal ions as metal-phosphate and the amount of metal precipitated was derived by estimating the reduction in the free metal ion present in the supernatant of reactions employing atomic absorption spectrophotometer (AAS). Better precipitation of metal was obtained at pH 11 than at pH 8 and between the two concentrations of different metals tested, an initial metal concentration of 250 ppm in the reaction gave more precipitation than with 1000 ppm. Experimental data showed that at pH 11, the percentage of removal of metal ions (for an initial concentration of 250 ppm) was in the following order: Cd(2+) (80.99%) > Ni(2+) (64.78%) > Cr(3+) > (46.15%) > Co(2+) (36.47%) > Cr(6+) (32.33%). The overall removal of Cr(3+) and Cr(6+) from tannery effluent was 32.77% and 37.39% respectively in 120 min at pH 11. Likewise, the overall removal of Cd(2+), Co(2+) and Ni(2+) from electroplating effluent was 50.42%, 13.93% and 38.64% respectively in 120 min at pH 11. The study demonstrates that bioprecipitation by CIAP may be a viable and environmental friendly method for clean-up of heavy metals from tannery and electroplating effluents.

  14. Serial incorporation of a monovalent GalNAc phosphoramidite unit into hepatocyte-targeting antisense oligonucleotides.

    Science.gov (United States)

    Yamamoto, Tsuyoshi; Sawamura, Motoki; Wada, Fumito; Harada-Shiba, Mariko; Obika, Satoshi

    2016-01-01

    The targeting of abundant hepatic asialoglycoprotein receptors (ASGPR) with trivalent N-acetylgalactosamine (GalNAc) is a reliable strategy for efficiently delivering antisense oligonucleotides (ASOs) to the liver. We here experimentally demonstrate the high systemic potential of the synthetically-accessible, phosphodiester-linked monovalent GalNAc unit when tethered to the 5'-terminus of well-characterised 2',4'-bridged nucleic acid (also known as locked nucleic acid)-modified apolipoprotein B-targeting ASO via a bio-labile linker. Quantitative analysis of the hepatic disposition of the ASOs revealed that phosphodiester is preferable to phosphorothioate as an interunit linkage in terms of ASGPR binding of the GalNAc moiety, as well as the subcellular behavior of the ASO. The flexibility of this monomeric unit was demonstrated by attaching up to 5 GalNAc units in a serial manner and showing that knockdown activity improves as the number of GalNAc units increases. Our study suggests the structural requirements for efficient hepatocellular targeting using monovalent GalNAc and could contribute to a new molecular design for suitably modifying ASO.

  15. [Safety and tolerability of monovalent measles and combined measles, mumps, rubella, and varicella vaccines].

    Science.gov (United States)

    Mentzer, D; Meyer, H; Keller-Stanislawski, B

    2013-09-01

    Although effective monovalent and combined measles vaccines have been available for several decades in Germany, measles outbreaks continue to occur leading to severe cases of measles and even death. Possible reasons for the low acceptance of the measles vaccination are concerns about adverse events and serious complications following vaccination. In this report, we have summarized and assessed all adverse events reported in Germany from 2001 to 2012 after vaccination with monovalent- and combined measles-containing vaccines. A total of 1,696 suspected adverse reaction reports describing 5,297 adverse events were sent to the Paul Ehrlich Institute (PEI) between 1 January 2001 and 31 December 2012. The calculated mean reporting rate was 5.7 reports per 100,000 vaccine doses released by the PEI. Analysis of the reports indicates that measles-containing vaccines are well tolerated with a constantly low rate of adverse events reported. Compared to the high rate of serious complications following wild-type measles infection, the benefit of measles-containing vaccines clearly outweighs the anticipated risks of adverse events.

  16. Defect engineering of single- and few-layer MoS2 by swift heavy ion irradiation

    Science.gov (United States)

    Madauß, Lukas; Ochedowski, Oliver; Lebius, Henning; Ban-d'Etat, Brigitte; Naylor, Carl H.; Johnson, A. T. Charlie; Kotakoski, Jani; Schleberger, Marika

    2017-03-01

    We have investigated the possibility to use swift heavy ion irradiation for nano-structuring supported and freestanding ultra-thin MoS2 samples. Our comprehensive study of the ion-induced morphological changes in various MoS2 samples shows that depending on the irradiation parameters a multitude of extended defects can be fabricated. These range from chains of nano-hillocks in bulk-like MoS2, and foldings in single and bilayer MoS2, to unique nano-incisions in supported and freestanding single layers of MoS2. Our data reveals that the primary mechanism responsible for the incisions in the ultrathin supported samples is the indirect heating by the SiO2 substrate. We thus conclude that an energy of less than 2 keV per nm track length is sufficient to fabricate nano-incisions in MoS2 which is compatible with the use of the smallest accelerators.

  17. Excited state dynamics of the Ho3+ ions in holmium singly doped and holmium, praseodymium-codoped fluoride glasses

    Science.gov (United States)

    Librantz, André Felipe Henriques; Jackson, Stuart D.; Jagosich, Fabio Henrique; Gomes, Laércio; Poirier, Gaël; Ribeiro, Sidney José Lima; Messaddeq, Younes

    2007-06-01

    The deactivation of the two lowest excited states of Ho3+ was investigated in Ho3+ singly doped and Ho3+, Pr3+-codoped fluoride (ZBLAN) glasses. We establish that 0.1-0.3mol% Pr3+ can efficiently deactivate the first excited (I75) state of Ho3+ while causing a small reduction of ˜40% of the initial population of the second excited (I65) state. The net effect introduced by the Pr3+ ion deactivation of the Ho3+ ion is the fast recovery of the ground state of Ho3+. The Burshstein model parameters relevant to the Ho3+→Pr3+ energy transfer processes were determined using a least squares fit to the measured luminescence decay. The energy transfer upconversion and cross relaxation parameters for 1948, 1151, and 532nm excitations of singly Ho3+-doped ZBLAN were determined. Using the energy transfer rate parameters we determine from the measured luminescence, a rate equation model for 650nm excitation of Ho3+-doped and Ho3+, Pr3+-doped ZBLAN glasses was developed. The rate equations were solved numerically and the population inversion between the I65 and the I75 excited states of Ho3+ was calculated to examine the beneficial effects on the gain associated with Pr3+ codoping.

  18. High ionic strength narrows the population of sites participating in protein ion-exchange adsorption: a single-molecule study.

    Science.gov (United States)

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P; Dominguez-Medina, Sergio; Kulla, Eliona; Kang, Marci K; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Dhamane, Sagar; Willson, Richard C; Landes, Christy F

    2014-05-23

    The retention and elution of proteins in ion-exchange chromatography is routinely controlled by adjusting the mobile phase salt concentration. It has repeatedly been observed, as judged from adsorption isotherms, that the apparent heterogeneity of adsorption is lower at more-eluting, higher ionic strength. Here, we present an investigation into the mechanism of this phenomenon using a single-molecule, super-resolution imaging technique called motion-blur Points Accumulation for Imaging in Nanoscale Topography (mbPAINT). We observed that the number of functional adsorption sites was smaller at high ionic strength and that these sites had reduced desorption kinetic heterogeneity, and thus narrower predicted elution profiles, for the anion-exchange adsorption of α-lactalbumin on an agarose-supported, clustered-charge ligand stationary phase. Explanations for the narrowing of the functional population such as inter-protein interactions and protein or support structural changes were investigated through kinetic analysis, circular dichroism spectroscopy, and microscopy of agarose microbeads, respectively. The results suggest the reduction of heterogeneity is due to both electrostatic screening between the protein and ligand and tuning the steric availability within the agarose support. Overall, we have shown that single molecule spectroscopy can aid in understanding the influence of ionic strength on the population of functional adsorbent sites participating in the ion-exchange chromatographic separation of proteins.

  19. The effect of the ammonium ion on activated-sludge settling properties

    DEFF Research Database (Denmark)

    Novak, John Thomas

    2001-01-01

    High levels of sodium in wastewater have been found to be detrimental to activated-sludge. settling and dewatering. Another potentially troublesome monovalent cation in activated-sludge systems is the ammonium ion. This study was conducted to determine if the ammonium ion could alter activated-sl...

  20. Influence of higher valent ions on flexible polyelectrolyte stiffness and counter-ion distribution.

    Science.gov (United States)

    Chremos, Alexandros; Douglas, Jack F

    2016-04-28

    We investigate the influence of counter-ion valency on the flexibility of highly charged flexible polymer chains using molecular dynamics simulations that include both salt and an explicit solvent. As observed experimentally, we find that divalent counter-ions greatly reduce the chain persistence length, lp, in comparison with monovalent counter-ions. On the other hand, polyelectrolyte chains having trivalent counter-ions adopt a much more compact conformation than polyelectrolytes having monovalent and divalent counter-ions. We demonstrate that the tendency of polyelectrolyte chains to become deformed by proximal high valence counter-ions is due to chain "coiling" around the counter-ions. In particular, we find that the number of contacts that the proximal counter-ions have with the polyelectrolyte dictates the extent of chain coiling. This ion-binding induced coiling mechanism influences not only the conformational properties of the polyelectrolyte, but also the counter-ion distribution around the chain. Specifically, we find that higher valent counter-ions lead both to a counter-ion enrichment in close proximity to the polyelectrolyte and to a significant reduction in the spatial extent of the diffuse counter-ion cloud around the polyelectrolyte.

  1. What Controls the Sign and Magnitude of Magnetic Anisotropy in Tetrahedral Cobalt(II) Single-Ion Magnets?

    Science.gov (United States)

    Vaidya, Shefali; Tewary, Subrata; Singh, Saurabh Kumar; Langley, Stuart K; Murray, Keith S; Lan, Yanhua; Wernsdorfer, Wolfgang; Rajaraman, Gopalan; Shanmugam, Maheswaran

    2016-10-03

    A family of mononuclear tetrahedral cobalt(II) thiourea complexes, [Co(L1)4](NO3)2 (1) and [Co(Lx)4](ClO4)2 where x = 2 (2), 3 (3), 4 (4) (where L1 = thiourea, L2 = 1,3-dibutylthiourea, L3 = 1,3-phenylethylthiourea, and L4 = 1,1,3,3-tetramethylthiourea), has been synthesized using a rationally designed synthetic approach, with the aim of stabilizing an Ising-type magnetic anisotropy (-D). On the basis of direct-current, alternating-current, and hysteresis magnetic measurements and theoretical calculations, we have identified the factors that govern the sign and magnitude of D and ultimately the ability to design a single-ion magnet for a tetrahedral cobalt(II) ion. To better understand the magnetization relaxation dynamics, particularly for complexes 1 and 2, dilution experiments were performed using their diamagnetic analogues, which are characterized by single-crystal X-ray diffraction with the general molecular formulas of [Zn(L1)4](NO3)2 (5) and [Zn(L2)4](ClO4)2 (6). Interestingly, intermolecular interactions are shown to play a role in quenching the quantum tunneling of magnetization in zero field, as evidenced in the hysteresis loop of 1. Complex 2 exhibits the largest Ueff value of 62 cm(-1) and reveals open hysteresis loops below 4 K. Furthermore, the influence of the hyperfine interaction on the magnetization relaxation dynamics is witnessed in the hysteresis loops, allowing us to determine the electron/nuclear spin S(Co) = (3)/2/I(Co) = (7)/2 hyperfine coupling constant of 550 MHz, a method ideally suited to determine the hyperfine coupling constant of highly anisotropic metal ions stabilized with large D value, which are otherwise hard to determine by conventional methods such as electron paramagnetic resonance.

  2. Single-Qubit-Gate Error below 0.0001 in a Trapped Ion

    Science.gov (United States)

    2011-01-01

    from the current state of the art (7 × 10−3 for laser-based [8] and 0.24 for microwave-based gates [9]) to similar levels. To determine the average...electrode trap structure [16]. The use of microwave radiation instead of optical stimulated- Raman transitions to drive qubit rotations suppresses deco ...higher powers. To investigate unintended laser light as a source of deco - herence, (e.g., from optical pumping), the ion is prepared in | ↓〉 and is allowed

  3. Triple-ion interactions for the construction of supramolecular capsules

    NARCIS (Netherlands)

    Oshovsky, G.; Reinhoudt, David; Verboom, Willem

    2006-01-01

    A novel type of [2+4] capsules based on triple-ion interactions was obtained. Four monovalent anions (bromide, nitrate, acetate, and tosylate) bring together two tetrakis(pyridiniummethyl)tetramethyl cavitands by pyridinium−anion−pyridinium interactions. ESI-MS experiments have confirmed the capsule

  4. Single top quark production in heavy ion collisions at the LHC

    CERN Document Server

    Baskakov, A V; Dudko, L V; Lokhtin, I P; Snigirev, A M

    2015-01-01

    The paper presents analysis of the single top quark production in PbPb collisions at the Large Hadron Collider at center-of-mass energy 5.5 TeV per nucleon pair. The analysis is performed with CompHEP and PYQUEN event generators. The neutron and proton content in the nuclei is taken into account. NLO precision has been implemented to simulate kinematic properties and rate of single top production. The modification of different characteristics of single top quark decay products due to interactions of jet partons in quark-gluon medium, and the specific charge asymmetry of top/anti-top quark yields due to the isospin effect are evaluated.

  5. Collective ion diffusion and localized single particle dynamics in pyridinium-based ionic liquids.

    Science.gov (United States)

    Burankova, Tatsiana; Hempelmann, Rolf; Wildes, Andrew; Embs, Jan P

    2014-12-11

    Quasielastic neutron scattering with polarized neutrons allows for an experimental separation of single-particle and collective processes, as contained in the incoherent and coherent scattering contributions. This technique was used to investigate the dynamical processes in the pyridinium-based ionic liquid 1-butylpyridinium bis(trifluoromethylsulfonyl)-imide. We observed two diffusion processes with different time scales. The slower diffusional process was present in both the coherent and the incoherent contribution, meaning that this process has at least a partial collective nature. The second faster localized process is only present in the incoherent scattering contribution. We conclude that it is a true single-particle process on a shorter time scale.

  6. Single-walled carbon nanotubes as stabilizing agents in red phosphorus Li-ion battery anodes

    KAUST Repository

    Smajic, Jasmin

    2017-08-16

    Phosphorus boasts extremely high gravimetric and volumetric capacities but suffers from poor electrochemical stability with significant capacity loss immediately after the first cycle. We propose to circumvent this issue by mixing amorphous red phosphorus with single-walled carbon nanotubes. Employing a non-destructive sublimation–deposition method, we have synthesized composites where the synergetic effect between red phosphorus and single-walled carbon nanotubes allows for a considerable improvement in the electrochemical stability of battery anodes. In contrast to the average 40% loss of capacity after 50 cycles for other phosphorus–carbon composites in the literature, our material shows losses of just 22% under analogous cycling conditions.

  7. Exchange interaction of strongly anisotropic tripodal erbium single-ion magnets with metallic surfaces

    DEFF Research Database (Denmark)

    Dreiser, Jan; Wäckerlin, Christian; Ali, Md. Ehesan

    2014-01-01

    on a Ni thin film on Cu(100) single-crystalline surfaces. X-ray magnetic circular dichroism (XMCD) measurements performed on Au(111) samples covered with molecular monolayers held at temperatures down to 4 K suggest that the easy axes of the strongly anisotropic molecules are randomly oriented...

  8. Light and molecular ions: the emergence of vacuum UV single-photon ionization in MS.

    Science.gov (United States)

    Hanley, Luke; Zimmermann, Ralf

    2009-06-01

    Thanks to recent technological advances and single-photon ionization's (SPI's) ability to detect all organics, the technique could become the long-sought universal soft ionization method. (To listen to a podcast about this feature, please go to the Analytical Chemistry Web site at pubs.acs.org/journal/ancham.).

  9. Titratable Macroions in Multivalent Electrolyte Solutions: Strong Coupling Dressed Ion Approach

    CERN Document Server

    Adzic, Natasa

    2016-01-01

    We present a theoretical description of the effect of polyvalent ions on the interaction between titratable macro-ions. The model system consists of two point-like macro-ions with dissociable sites, immersed in an asymmetric ionic mixture of monovalent and polyvalent salts. We formulate a {\\em dressed ion strong coupling theory}, based on the decomposition of the asymmetric ionic mixture into a weakly electrostatically coupled monovalent salt, and into polyvalent ions that are strongly electrostatically coupled to the titratable macro-ions. The charge of the macroions is not considered as fixed, but is allowed to respond to local bathing solution parameters (electrostatic potential, $pH$ of the solution, salt concentration) through a simple {\\em charge regulation} model. The approach presented, yielding an effective polyvalent-ion mediated interaction between charge-regulated macro-ions at various solution conditions, describes the strong coupling equivalent of the Kirkwood-Schumaker interaction.

  10. Microstructural evolution of reduced-activation martensitic steel under single and sequential ion irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Jin, Shuoxue; Li, Tiecheng; Zheng, Zhongcheng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yang, Feng; Xiong, Xuesong; Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-07-15

    Microstructural evolution of super-clean reduced-activation martensitic steels irradiated with single-beam (Fe{sup +}) and sequential-beam (Fe{sup +} plus He{sup +}) at 350 °C and 550 °C was studied. Sequential-beam irradiation induced smaller size and larger number density of precipitates compared to single-beam irradiation at 350 °C. The largest size of cavities was observed after sequential-beam irradiation at 550 °C. The segregation of Cr and W and depletion of Fe in carbides were observed, and the maximum depletion of Fe and enrichment of Cr occurred under irradiation at 350 °C.

  11. New insights into single-compound and binary adsorption of copper and lead ions on a treated sea mango shell: experimental and theoretical studies.

    Science.gov (United States)

    Sellaoui, Lotfi; Edi Soetaredjo, Felycia; Ismadji, Suryadi; Cláudio Lima, Éder; Dotto, Guilherme L; Ben Lamine, Abdelmottaleb; Erto, Alessandro

    2017-09-21

    Herein, adsorption isotherms of Pb(ii) and Cu(ii) ions on treated sea mango fruit in both single-compound and binary systems were experimentally realized at different temperatures in the range of 30-50 °C. Experimental results show that adsorption of Pb(ii) was more as compared to that of Cu(ii) ions; however, for both ions, a significant reduction in the adsorption capacity was observed in the binary system as compared to that in the single-compound systems. Moreover, under all the investigated conditions, adsorption seems to be promoted by an increase in temperature. To understand and interpret the experimental evidences, the Hill and competitive Hill models developed on the basis of the grand canonical ensemble were applied for the analysis of adsorption equilibrium data. These models contain some physicochemical parameters that allow an exhaustive analysis of the dynamics of single-compound and binary adsorptions. Based on the fitting results, in particular, through the evaluation of the number of ions bonded per site (n and ni), it was found that lead and copper ions interacted by inclined and horizontal positions on treated sea mango in single-compound and binary systems, respectively. In addition, based on the same parameters, a significant interaction between ions was retrieved. A study focused on the saturation adsorption capacity in single-compound and binary systems affirmed that the adsorbent was more selective for lead than for copper. The reduction of the adsorbed capacity ratio between the binary and single-compound systems (i.e. Qb/Qs) explained and confirmed that an inhibition effect between copper and lead ions at the same receptor site occurred. Finally, based on the energetic investigations, it was deduced that the adsorption energy represented the dominant factor promoting the greater adsorption of lead than that of copper in both systems.

  12. Fabrication of single TiO2 nanotube devices with Pt interconnections using electron- and ion-beam-assisted deposition

    Science.gov (United States)

    Lee, Mingun; Cha, Dongkyu; Huang, Jie; Ha, Min-Woo; Kim, Jiyoung

    2016-06-01

    Device fabrication using nanostructured materials, such as nanotubes, requires appropriate metal interconnections between nanotubes and electrical probing pads. Here, electron-beam-assisted deposition (EBAD) and ion-beam-assisted deposition (IBAD) techniques for fabrication of Pt interconnections for single TiO2 nanotube devices are investigated. IBAD conditions were optimized to reduce the leakage current as a result of Pt spreading. The resistivity of the IBAD-Pt was about three orders of magnitude less than that of the EBAD-Pt, due to low carbon concentration and Ga doping, as indicated by X-ray photoelectron spectroscopy analysis. The total resistances of single TiO2 nanotube devices with EBAD- or IBAD-Pt interconnections were 3.82 × 1010 and 4.76 × 108 Ω, respectively. When the resistivity of a single nanotube is low, the high series resistance of EBAD-Pt cannot be ignored. IBAD is a suitable method for nanotechnology applications, such as photocatalysis and biosensors.

  13. Observation of single-ion multiple-bit upsets in memories in space; Observation en vol, d'upsets multiples mono-ioniques, sur des memoires

    Energy Technology Data Exchange (ETDEWEB)

    Buchner, S.; Campbell, A.B.; Meehan, T.; McMorrow, D. [Naval Research Lab., Washington, DC (United States); Buchner, S. [SFA, Inc Largo, MD (United States); Dyer, C.; Sanderson, C.; Comber, C. [EDS Defense Limited, Hants (United Kingdom)

    1999-07-01

    Single-ion multiple-bit upsets (SIMBU) have been observed in 2 different types of memories aboard a spacecraft. There are 3 recognized mechanisms responsible for SIMBUs: 1) charge diffusing away from an ion track and collected by adjacent SEU-sensitive nodes (single event upset), 2) charge collected from an ion track passing through the circuit just below the surface and intersecting a number of memory cells in a straight line, and 3) ion strikes to control circuitry. All the SIMBUs from MPTB (microelectronics and photonics test-bed) have been attributed to one of the 3 mechanisms described above. Bit-maps of the memories are essential for determining the physical locations of the upsets. For this study the bit-maps have been obtained with pulsed lasers. (A.C.)

  14. A Single Pulse Beam Emittance Measurement for the CERN Heavy Ion Linac

    CERN Document Server

    Crescenti, M

    1995-01-01

    A new device for transverse emittance measurement has been installed in the 4.2 MeV/u filter region of the CERN Heavy Ion Linac (Linac 3). It allows to obtain pulse-to-pulse (every 1.2 sec) visualisation of the Linac 3 beam parameters in order to tune the machine and to match the beam for injection into the first circular accelerator, the PS Booster. The system is based on the "multi-slit" technique similar to the well-known "pepper pot" method. A plate with a series of horizontal or vertical slits is placed in the beam, defining positions in the phase plane. Particles pass through the slits and drift to a scintillator screen where they produce light. The screen is looked at by an externally triggered high resolution CCD camera. For each slit position the light intensity distribution, in the limit of infinitesimal slit aperture, is proportional to the angle distribution of the particles and therefore, provides the angular distribution in the phase plane. The video signal from the camera is digitised and the r...

  15. Single step purification of recombinant proteins using the metal ion-inducible autocleavage (MIIA) domain as linker for tag removal.

    Science.gov (United States)

    Ibe, Susan; Schirrmeister, Jana; Zehner, Susanne

    2015-08-20

    For fast and easy purification, proteins are typically fused with an affinity tag, which often needs to be removed after purification. Here, we present a method for the removal of the affinity tag from the target protein in a single step protocol. The protein VIC_001052 of the coral pathogen Vibrio coralliilyticus ATCC BAA-450 contains a metal ion-inducible autocatalytic cleavage (MIIA) domain. Its coding sequence was inserted into an expression vector for the production of recombinant fusion proteins. Following, the target proteins MalE and mCherry were produced as MIIA-Strep fusion proteins in Escherichia coli. The target proteins could be separated from the MIIA-Strep part simply by the addition of calcium or manganese(II) ions within minutes. The cleavage is not affected in the pH range from 5.0 to 9.0 or at low temperatures (6°C). Autocleavage was also observed with immobilized protein on an affinity column. The protein yield was similar to that achieved with a conventional purification protocol.

  16. Multiphysics simulation of ion concentration polarization induced by a surface-patterned nanoporous membrane in single channel devices.

    Science.gov (United States)

    Jia, Mingjie; Kim, Taesung

    2014-10-21

    Microfluidic devices utilize ion concentration polarization (ICP) phenomena for a variety of applications, but a comprehensive understanding of the generation of ICP is still necessary. Recently, the emergence of a novel single channel ICP (SC-ICP) device has stimulated further research on the mechanism of ICP generation, so that we developed a 2-D model of an SC-ICP device that integrates a nanoporous membrane on the bottom surface of the channel, allowing bulk flow over the membrane. We solved a set of coupled governing equations with appropriate boundary conditions to explore ICP numerically. As a result, we not only showed that the simulation results held a strong qualitative agreement with experimental results, but also found the distribution of ion concentrations in the SC-ICP device that has never been reported in previous studies. We confirmed again that the electrophoretic mobility (EPM) of counterions in the membrane is the most dominant factor determining the generation and strength of ICP, whereas the charge density of the membrane was dominant to the ICP strength only when a high EPM value was assumed. From the viewpoint of practical applications, an SC-ICP device with a long membrane under low buffer strength showed enhanced performance in the preconcentration of charged molecules. Therefore, we believe that the simulation results could not only provide sharp insight into ICP phenomena but also predict and optimize the performance of SC-ICP devices in various microfluidic applications.

  17. Charge transport and glassy dynamics of poly(ethylene oxide)-based single-ion conductors under geometrical confinement

    Science.gov (United States)

    Runt, James; Iacob, Ciprian

    2015-03-01

    Segmental and local dynamics as well as charge transport are investigated in a series of poly(ethylene oxide)-based single-ion conductors (ionomers) with varying counterions (Li +, Na +) confined in uni-directional nanoporous silica membranes. The dynamics are explored over a wide frequency and temperature range by broadband dielectric relaxation spectroscopy. Slowing of segmental dynamics and a decrease in dc conductivity (strongly coupled with segmental relaxation) of the confined ionomers are associated with surface effects - resulting from interfacial hydrogen bonding between the host nanoporous silica membrane and the guest ionomers. These effects are significantly reduced or eliminated upon pore surface modification through silanization. The primary transport properties for the confined ionomers decrease by about one decade compared to the bulk ionomer. A model assuming reduced mobility of an adsorbed layer at the pore wall/ionomer interface is shown to provide a quantitative explanation for the decrease in effective transport quantities in non-silanized porous silica membranes. Additionally, the effect of confinement on ion aggregation in ionomers by using X-ray scattering will also be discussed. Supported by the National Science Foundation, Polymers Program.

  18. Differential cross sections for single ionization of Li in collisions with fast protons and O$^{8+}$ ions

    CERN Document Server

    Gulyás, L; Kirchner, T

    2015-01-01

    We study the process of single ionization of Li in collisions with H$^+$ and O$^{8+}$ projectile ions at 6 MeV and 1.5-MeV/amu impact energies, respectively. Using the frameworks of the independent-electron model and the impact parameter picture, fully (FDCS) and doubly (DDCS) differential cross sections are evaluated in the continuum distorted-wave with eikonal initial-state approximation. Comparisons are made with the recent measurements of LaForge \\textit{et al} [J. Phys. B \\textbf{46} 031001 (2013)] for the DDCS and Hubele \\textit{et al} [Phys. Rev. Lett. \\textbf{110} 133201 (2013)] for the FDCS, respectively. For O$^{8+}$ impact inclusion of the heavy particle (NN) interaction in the calculations is crucial and effects of polarization due to the presence of the projectile ion have also to be taken into account for getting very good agreement with the measured data. Our calculation reproduces the satellite peak structure seen in the FDCS for the Li(2s) measurement, which we explain as being formed by a co...

  19. Single-particle detection of products from atomic and molecular reactions in a cryogenic ion storage ring

    Science.gov (United States)

    Krantz, C.; Novotný, O.; Becker, A.; George, S.; Grieser, M.; Hahn, R. von; Meyer, C.; Schippers, S.; Spruck, K.; Vogel, S.; Wolf, A.

    2017-04-01

    We have used a single-particle detector system, based on secondary electron emission, for counting low-energetic (∼keV/u) massive products originating from atomic and molecular ion reactions in the electrostatic Cryogenic Storage Ring (CSR). The detector is movable within the cryogenic vacuum chamber of CSR, and was used to measure production rates of a variety of charged and neutral daughter particles. In operation at a temperature of ∼ 6 K , the detector is characterised by a high dynamic range, combining a low dark event rate with good high-rate particle counting capability. On-line measurement of the pulse height distributions proved to be an important monitor of the detector response at low temperature. Statistical pulse-height analysis allows to infer the particle detection efficiency of the detector, which has been found to be close to unity also in cryogenic operation at 6 K.

  20. Modulational instability and localized modes in Heisenberg ferromagnetic chains with single-ion easy-axis anisotropy

    Science.gov (United States)

    Tang, Bing; Li, Guang-Ling; Fu, Mei

    2017-03-01

    A semiclassical theoretical study on the property of the modulational instability of corresponding linear spin-waves and the presence of nonlinear localized excitations in a discrete quantum ferromagnetic spin chain with single-ion easy-axis anisotropy is reported. We consider the Glauber coherent-state representation combined with the Dyson-Maleev transformation for local spin operators as the basic representation of the system, and derive the equation of motion by means of the Ehrenfest theorem. Using a modulational instability analysis of plane waves, we predict the existence regions of bright envelope solitons and intrinsic localized spin-wave modes. Besides, with the help of a semidiscrete multi-scale method, we obtain analytical solutions for the bright envelope soliton and intrinsic localized spin-wave mode. Moreover, we analyze their existence conditions, which agree with the results of modulational instability analysis.

  1. Fully differential cross sections in single ionization of helium by ion impact: Assessing the role of correlated wave functions

    Energy Technology Data Exchange (ETDEWEB)

    Ciappina, M.F. [Max Planck Institute for the Physics of Complex Systems, Noethnitzer Str. 38, D-01187, Dresden (Germany)], E-mail: ciappi@pks.mpg.de; Cravero, W.R. [CONICET and Departamento de Fisica, Universidad Nacional del Sur, Av. Alem 1253, B8000CPB, Bahia Blanca (Argentina)

    2008-02-15

    We study the effect of final state dynamic correlation in single ionization of atoms by ion impact analyzing fully differential cross sections (FDCS). We use a distorted wave model where the final state is represented by a {phi}{sub 2} type correlated function, solution of a non-separable three body continuum Hamiltonian. This final state wave function partially includes the correlation of electron-projectile and electron-recoil relative motion as coupling terms of the wave equation. A comparison of fully differential results using this model with other theories and experimental data reveals that inclusion of dynamic correlation effects have little influence on FDCS, and do not contribute to a better description of available data in the case of electronic emission out-of scattering plane.

  2. Thermal property of regioregular poly(3-hexylthiophene)/nanotube composites using modified single-walled carbon nanotubes via ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, A R [College of Nanoscale Science and Engineering, State University of New York, Albany, NY 12203 (United States); Huang, M [College of Nanoscale Science and Engineering, State University of New York, Albany, NY 12203 (United States); Bakhru, H [College of Nanoscale Science and Engineering, State University of New York, Albany, NY 12203 (United States); Chipara, M [Department of Physics and Geology, University of Texas Pan American, Edinburg, TX 78541-2999 (United States); Ryu, C Y [Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Ajayan, P M [Department of Material Science and Engineering, Rensselaer Polytechnic Institute, Troy and Rensselaer Nanotechnology Center, NY 12180 (United States)

    2006-12-28

    The effects of radiation-induced modifications on the thermal stability and phase transition behaviour of composites made of 1% pristine or ion irradiated single-walled carbon nanotubes (SWNTs) and poly(3-hexylthiophene) (P3HT) are reported. Thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Raman spectroscopy and electron spin resonance (ESR) were used to investigate the radiation-induced functionalization of carbon nanotubes and to assess the effect of ionizing radiation on the adhesion between macromolecular polymer and carbon nanotubes. Irradiation was used to introduce defects in a controlled way solely within pristine nanotubes before composite synthesis. The addition of irradiated SWNTs to a polymer matrix was found to enhance thermo-oxidative stability and phase transition behaviour. Further, ESR studies demonstrate the electronic interaction through charge transfer between filler and matrix. These results could have immense applications in nanotube composite processing. Based on the experimental data, a model for the interaction between polymeric chains and carbon nanotubes is proposed.

  3. International collaboration to assess the risk of Guillain Barre Syndrome following Influenza A (H1N1) 2009 monovalent vaccines

    NARCIS (Netherlands)

    Dodd, Caitlin N.; Romio, Silvana A.; Black, Steven; Vellozzi, Claudia; Andrews, Nick; Sturkenboom, Miriam; Zuber, Patrick; Hua, Wei; Bonhoeffer, Jan; Buttery, Jim; Crawford, Nigel; Deceuninck, Genevieve; de Vries, Corinne; De Wals, Philippe; Gutierrez-Gimeno, M. Victoria; Heijbel, Harald; Hughes, Hayley; Hur, Kwan; Hviid, Anders; Kelman, Jeffrey; Kilpi, Tehri; Chuang, S. K.; Macartney, Kristine; Rett, Melisa; Lopez-Callada, Vesta Richardson; Salmon, Daniel; Sanchez, Francisco Gimenez; Sanz, Nuria; Silverman, Barbara; Storsaeter, Jann; Thirugnanam, Umapathi; van der Maas, Nicoline; Yih, Katherine; Zhang, Tao; Izurieta, Hector

    2013-01-01

    Background: The global spread of the 2009 novel pandemic influenza A (H1N1) virus led to the accelerated production and distribution of monovalent 2009 Influenza A (H1N1) vaccines (pH1N1). This pandemic provided the opportunity to evaluate the risk of Guillain-Barre syndrome (GBS), which has been an

  4. In vitro neutralisation of rotavirus infection by two broadly specific recombinant monovalent llama-derived antibody fragments

    NARCIS (Netherlands)

    F. Aladin (Farah); A.W.C. Einerhand (Sandra); J. Bouma (Janneke); S. Bezemer (Sandra); P. Hermans (Pim); D. Wolvers (Danielle); K. Bellamy (Kate); L.G.J. Frenken (Leon); J. Gray (Jim); M. Iturriza-Gómara (Miren)

    2012-01-01

    textabstractRotavirus is the main cause of viral gastroenteritis in young children. Therefore, the development of inexpensive antiviral products for the prevention and/or treatment of rotavirus disease remains a priority. Previously we have shown that a recombinant monovalent antibody fragment (refe

  5. Polyelectrolyte-like behaviour of poly(ethylene-oxide) solutions with added monovalent salt

    Science.gov (United States)

    Lal, Jyotsana; Hakem, Ilhem-Faiza

    2004-03-01

    Solvent effects on the conformation of poly(ethylene-oxide) (PEO) and complexation of PEO by monovalent cations, have been examined by using small-angle neutron scattering. In methanol and acetonitrile, a big change in interchain interaction, osmotic compressibility and local chain conformation have been observed upon addition of small amounts of potassium iodide. The amplitude of the total intensity decreases significantly and a peak at a certain value of the wavevector q* appears as signature of a polyelectrolyte-like behaviour. With further addition of salt, the ionic strength of the solution increases and potassium binding becomes less favorable: the binding constant decreases with the ionic strength and PEO behaves as a neutral polymer with excluded volume. No association between PEO and potassium iodide was observed in aqueous solutions. Reference: I.F. Hakem and J. Lal. Europhysics letters, 64 (2), 204, 2003

  6. Negative Ion MALDI Mass Spectrometry of Polyoxometalates (POMs): Mechanism of Singly Charged Anion Formation and Chemical Properties Evaluation

    Science.gov (United States)

    Boulicault, Jean E.; Alves, Sandra; Cole, Richard B.

    2016-08-01

    MALDI-MS has been developed for the negative ion mode analysis of polyoxometalates (POMs). Matrix optimization was performed using a variety of matrix compounds. A first group of matrixes offers MALDI mass spectra containing abundant intact singly charged anionic adduct ions, as well as abundant in-source fragmentations at elevated laser powers. A relative ranking of the ability to induce POM fragmentation is found to be: DAN > CHCA > CNA > DIT> HABA > DCTB > IAA. Matrixes of a second group provide poorer quality MALDI mass spectra without observable fragments. Sample preparation, including the testing of salt additives, was performed to optimize signals for a model POM, POMc12, the core structure of which bears four negative charges. The matrix 9-cyanoanthracene (CNA) provided the best signals corresponding to singly charged intact POMc12 anions. Decompositions of these intact anionic species were examined in detail, and it was concluded that hydrogen radical-induced mechanisms were not prevalent, but rather that the observed prompt fragments originate from transferred energy derived from initial electronic excitation of the CNA matrix. Moreover, in obtained MALDI mass spectra, clear evidence of electron transfer to analyte POM species was found: a manifestation of the POMs ability to readily capture electrons. The affinity of polyanionic POMc12 toward a variety of cations was evaluated and the following affinity ranking was established: Fe3+ > Al3+ > Li+ > Ga3+ > Co2+ > Cr3+ > Cu2+ > [Mn2+, Mg2+] > [Na+, K+]. Thus, from the available cationic species, specific adducts are preferentially formed, and evidence is given that these higher affinity POM complexes are formed in the gas phase during the early stages of plume expansion.

  7. A New Radio Frequency Plasma Oxygen Primary Ion Source on Nano Secondary Ion Mass Spectrometry for Improved Lateral Resolution and Detection of Electropositive Elements at Single Cell Level.

    Science.gov (United States)

    Malherbe, Julien; Penen, Florent; Isaure, Marie-Pierre; Frank, Julia; Hause, Gerd; Dobritzsch, Dirk; Gontier, Etienne; Horréard, François; Hillion, François; Schaumlöffel, Dirk

    2016-07-19

    An important application field of secondary ion mass spectrometry at the nanometer scale (NanoSIMS) is the detection of chemical elements and, in particular, metals at the subcellular level in biological samples. The detection of many trace metals requires an oxygen primary ion source to allow the generation of positive secondary ions with high yield in the NanoSIMS. The duoplasmatron oxygen source is commonly used in this ion microprobe but cannot achieve the same quality of images as the cesium primary ion source used to produce negative secondary ions (C(-), CN(-), S(-), P(-)) due to a larger primary ion beam size. In this paper, a new type of an oxygen ion source using a rf plasma is fitted and characterized on a NanoSIMS50L. The performances of this primary ion source in terms of current density and achievable lateral resolution have been characterized and compared to the conventional duoplasmatron and cesium sources. The new rf plasma oxygen source offered a net improvement in terms of primary beam current density compared to the commonly used duoplasmatron source, which resulted in higher ultimate lateral resolutions down to 37 nm and which provided a 5-45 times higher apparent sensitivity for electropositive elements. Other advantages include a better long-term stability and reduced maintenance. This new rf plasma oxygen primary ion source has been applied to the localization of essential macroelements and trace metals at basal levels in two biological models, cells of Chlamydomonas reinhardtii and Arabidopsis thaliana.

  8. Thermal and radiative characteristics of oxyfluoride glass singly doped with lanthanide ions

    Institute of Scientific and Technical Information of China (English)

    Barbara; Gra(z)yna; DOMINIAK-DZIK; RYBA-ROMANOWSKI

    2010-01-01

    Rare earths-doped oxyfluoride glasses based on germanium oxide and lead fluoride were prepared from commercial raw materials.The glasses with general composition of 50GeO2-(50-x-y)PbO-yPbF2-xLnF3(Ln=Pr3+-Yb3+),contained different concentrations of optically active dopants(x=0.2 mol.% and 2 mol.%)and PbF2(y≤15 mol.%).The differential thermal analysis(DTA)was used to determine both thermal characteristic and thermal stability properties of the glasses in the function of the kind of dopant,its concentration,and a glass composition.Characteristic glass temperatures such as glass transition temperature(Tg),glass crystallization temperature(Tc)and temperature corresponding to the maximum of the crystallization rate(Tpc)were evaluated.On the basis of obtained results,the thermal stabilities of glasses under study were evaluated using various thermal stability criteria(Dietzel factor △T,Saad-Poulain factors H' and S').It was found that the increase in rare earth fluoride contents influenced thermal characteristics when the characteristic temperatures of the individual glass was shifted towards higher values.The effect of the PbF2 content and the kind of rare earth impurity on the glass stability was observed.Absorption spectra of lanthanide-doped glasses were measured at room temperature and used to determine the phenomenological intensity parameters Ωt and next,to estimate radiative properties of lanthanide ions in this matrix.Radiative transition probabilities of luminescent states of Ln3+,branching ratios and radiative lifetimes were determined.The variation of the Ωt along the lanthanide series was presented and discussed.

  9. Role of crystallographic anisotropy in the formation of surface layers of single NiTi crystals after ion-plasma alloying

    Energy Technology Data Exchange (ETDEWEB)

    Poletika, T. M., E-mail: poletm@ispms.tsc.ru; Girsova, S. L., E-mail: llm@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Meisner, L. L., E-mail: girs@ispms.tsc.ru; Meisner, S. N., E-mail: msn@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation); Shulepov, I. A., E-mail: iashulepov@tpu.ru [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    The structure of the surface and near-surface layers of single crystals of NiTi, differently oriented relative to the direction of ion beam treatment was investigated. The role of the crystallographic orientation in formation of structure of surface layers after ion-plasma alloying was revealed. It was found that the orientation effects of selective sputtering and channeling determine the thickness of the oxide and amorphous layers, the depth of penetration of ions and impurities, the distribution of Ni with depth.

  10. Single-ion-magnet behavior in a two-dimensional coordination polymer constructed from Co(II) nodes and a pyridylhydrazone derivative.

    Science.gov (United States)

    Liu, Xiangyu; Sun, Lin; Zhou, Huiliang; Cen, Peipei; Jin, Xiaoyong; Xie, Gang; Chen, Sanping; Hu, Qilin

    2015-09-21

    A novel two-dimensional (2D) coordination polymer, [Co(ppad)2]n (1), resulted from the assembly of Co(II) ions based on a versatile ligand termed N(3)-(3-pyridoyl)-3-pyridinecarboxamidrazone. Alternating/direct-current magnetic studies of compound 1 indicate that the spatially separated high-spin Co(II) ions act as single-ion magnets (SIMs). The present work represents the first case of a 2D Co(II)-based SIM composed of a monocomponent organic spacer.

  11. Optimization of large area YBa sub 2 Cu sub 3 O sub 7-x films by single target ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Gauzzi, A.; Lucia, M.L.; Affronte, M.; Pavuna, D. (Inst. for Micro- and Optoelectronics, Swiss Federal Inst. of Tech. (EPFL), Lausanne (Switzerland))

    1991-12-01

    We report on the in-situ growth over large area of high-quality homogeneous YBa{sub 2}Cu{sub 3}O{sub 7-x} films by single target ion beam sputtering. The '123' stoichiometry transfer to the substrates is obtained by using sufficiently low power ion beam and a grazing angle between the ion beam and the target. The as-deposited films show consistent homogeneity and reproducible superconducting properties ({Delta}Tc<1 K, j{sub c}(77K)>10{sup 6} A cm{sup -2} at 77K) over areas larger than {approx equal}30 cm{sup 2}. (orig.).

  12. Single-molecule TPM studies on the conversion of human telomeric DNA.

    Science.gov (United States)

    Chu, Jen-Fei; Chang, Ta-Chau; Li, Hung-Wen

    2010-04-21

    Human telomere contains guanine-rich (G-rich) tandem repeats of single-stranded DNA sequences at its 3' tail. The G-rich sequences can be folded into various secondary structures, termed G-quadruplexes (G4s), by Hoogsteen basepairing in the presence of monovalent cations (such as Na+ and K+). We developed a single-molecule tethered particle motion (TPM) method to investigate the unfolding process of G4s in the human telomeric sequence AGGG(TTAGGG)3 in real time. The TPM method monitors the DNA tether length change caused by formation of the G4, thus allowing the unfolding process and structural conversion to be monitored at the single-molecule level. In the presence of its antisense sequence, the folded G4 structure can be disrupted and converted to the unfolded conformation, with apparent unfolding time constants of 82 s and 3152 s. We also observed that the stability of the G4 is greatly affected by different monovalent cations. The folding equilibrium constant of G4 is strongly dependent on the salt concentration, ranging from 1.75 at 5 mM Na+ to 3.40 at 15 mM Na+. Earlier spectral studies of Na+- and K+-folded states suggested that the spectral conversion between these two different folded structures may go through a structurally unfolded intermediate state. However, our single-molecule TPM experiments did not detect any totally unfolded intermediate within our experimental resolution when sodium-folded G4 DNA molecules were titrated with high-concentration, excess potassium ions. This observation suggests that a totally unfolding pathway is likely not the major pathway for spectral conversion on the timescale of minutes, and that interconversion among folded states can be achieved by the loop rearrangement. This study also demonstrates that TPM experiments can be used to study conformational changes in single-stranded DNA molecules.

  13. Unique kinase catalytic mechanism of AceK with a single magnesium ion.

    Directory of Open Access Journals (Sweden)

    Quanjie Li

    Full Text Available Isocitrate dehydrogenase kinase/phosphatase (AceK is the founding member of the protein phosphorylation system in prokaryotes. Based on the novel and unique structural characteristics of AceK recently uncovered, we sought to understand its kinase reaction mechanism, along with other features involved in the phosphotransfer process. Herein we report density functional theory QM calculations of the mechanism of the phosphotransfer reaction catalysed by AceK. The transition states located by the QM calculations indicate that the phosphorylation reaction, catalysed by AceK, follows a dissociative mechanism with Asp457 serving as the catalytic base to accept the proton delivered by the substrate. Our results also revealed that AceK prefers a single Mg(2+-containing active site in the phosphotransfer reaction. The catalytic roles of conserved residues in the active site are discussed.

  14. Single photons, dileptons and hadrons from relativistic heavy ion collisions and quark-hadron phase transition

    Indian Academy of Sciences (India)

    Dinesh Kumar Srivastava

    2001-08-01

    The production of single photons in Pb+Pb collisions at the CERN SPS as measured by the WA98 experiment is analysed. A quark gluon plasma is assumed to be formed initially, which expands, cools, hadronizes, and undergoes freeze-out. A rich hadronic equation of state is used and the transverse expansion of the interacting system is taken into account. The recent estimates of photon production in quark-matter (at two loop level) along with the dominant reactions in the hadronic matter leading to photons are used. About half of the radiated photons are seen to have a thermal origin. The same treatment and the initial conditions provide a very good description to hadronic spectra measured by several groups and the intermediate mass dileptons measured by the NA50 experiment, lending a strong support to the conclusion that quark gluon plasma has been formed in these collisions. Predictions for RHIC and LHC energies are also given.

  15. CID of singly charged antioxidants applied in lubricants by means of a 3D ion trap and a linear ion trap-Orbitrap mass spectrometer.

    Science.gov (United States)

    Kassler, Alexander; Pittenauer, Ernst; Doerr, Nicole; Allmaier, Guenter

    2011-06-01

    The aim of this study was to investigate the fragmentation behavior induced by low-energy collision-induced dissociation (LE-CID) of four selected antioxidants applied in lubricants, by two different types of ion trap mass spectrometers: a three-dimensional ion trap (3D-IT) and a linear IT (LIT) Orbitrap MS. Two sterically hindered phenols and two aromatic amines were selected as model compounds representing different antioxidant classes and were characterized by positive-ion electrospray ionization (ESI) and LE-CID. Various types of molecular ions (e.g. [M](+•) , [M + H](+) , [M + NH(4) ](+) or [M + Na](+) ) were used as precursor ions generating a significant number of structurally relevant product ions. Furthermore, the phenolic compounds were analyzed by negative-ion ESI. For both IT types applied for fragmentation, the antioxidants exhibited the same unusual LE-CID behavior: (1) they formed stable radical product ions and (2) CC bond cleavages of aliphatic substituents were observed and their respective cleavage sites depended on the precursor ion selected. This fragmentation provided information on the type of structural isomer usually not obtainable for branched aliphatic substituents utilizing LE-CID. Comparing the two instruments, the main benefit of applying the LIT-Orbitrap was direct access to elemental composition of product ions enabling unambiguous interpretation of fragmentation trees not obtainable by the 3D-IT device (e.g. loss of isobaric neutrals). It should be emphasized that the types of product ions formed do not depend on the type of IT analyzer applied. For characterizing degradation products of antioxidants, the LIT-Orbitrap hybrid system, allowing the determination of accurate m/z values for product ions, is the method of choice.

  16. A permeation theory for single-file ion channels: One- and two-step models

    Science.gov (United States)

    Nelson, Peter Hugo

    2011-04-01

    How many steps are required to model permeation through ion channels? This question is investigated by comparing one- and two-step models of permeation with experiment and MD simulation for the first time. In recent MD simulations, the observed permeation mechanism was identified as resembling a Hodgkin and Keynes knock-on mechanism with one voltage-dependent rate-determining step [Jensen et al., PNAS 107, 5833 (2010)]. These previously published simulation data are fitted to a one-step knock-on model that successfully explains the highly non-Ohmic current-voltage curve observed in the simulation. However, these predictions (and the simulations upon which they are based) are not representative of real channel behavior, which is typically Ohmic at low voltages. A two-step association/dissociation (A/D) model is then compared with experiment for the first time. This two-parameter model is shown to be remarkably consistent with previously published permeation experiments through the MaxiK potassium channel over a wide range of concentrations and positive voltages. The A/D model also provides a first-order explanation of permeation through the Shaker potassium channel, but it does not explain the asymmetry observed experimentally. To address this, a new asymmetric variant of the A/D model is developed using the present theoretical framework. It includes a third parameter that represents the value of the "permeation coordinate" (fractional electric potential energy) corresponding to the triply occupied state n of the channel. This asymmetric A/D model is fitted to published permeation data through the Shaker potassium channel at physiological concentrations, and it successfully predicts qualitative changes in the negative current-voltage data (including a transition to super-Ohmic behavior) based solely on a fit to positive-voltage data (that appear linear). The A/D model appears to be qualitatively consistent with a large group of published MD simulations, but no

  17. Fine-tuning the local symmetry to attain record blocking temperature and magnetic remanence in a single-ion magnet.

    Science.gov (United States)

    Ungur, Liviu; Le Roy, Jennifer J; Korobkov, Ilia; Murugesu, Muralee; Chibotaru, Liviu F

    2014-04-22

    Remanence and coercivity are the basic characteristics of permanent magnets. They are also tightly correlated with the existence of long relaxation times of magnetization in a number of molecular complexes, called accordingly single-molecule magnets (SMMs). Up to now, hysteresis loops with large coercive fields have only been observed in polynuclear metal complexes and metal-radical SMMs. On the contrary, mononuclear complexes, called single-ion magnets (SIM), have shown hysteresis loops of butterfly/phonon bottleneck type, with negligible coercivity, and therefore with much shorter relaxation times of magnetization. A mononuclear Er(III) complex is presented with hysteresis loops having large coercive fields, achieving 7000 Oe at T=1.8 K and field variation as slow as 1 h for the entire cycle. The coercivity persists up to about 5 K, while the hysteresis loops persist to 12 K. Our finding shows that SIMs can be as efficient as polynuclear SMMs, thus opening new perspectives for their applications.

  18. Effective tuning of the ratio of red to green emission of Ho{sup 3+} ions in single LiLuF{sub 4} microparticle via codoping Ce{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei, E-mail: gaowei@xupt.edu.cn; Dong, Jun; Liu, Jihong; Yan, Xuewen

    2016-09-15

    Yb{sup 3+}/Ho{sup 3+} codoped LiLuF{sub 4} microparticles have been successfully prepared via a facile hydrothermal method. The crystal phase and morphology of LiLuF{sub 4} microparticles were inspected by x-ray diffraction and scanning electron microscope, respectively. The upconversion emission of single LiLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} microparticle was carefully studied by a confocal microscopy setup under NIR 980 nm excitation. With the increase of Ce{sup 3+} ion concentrations of 12%, the ratio of red to green emission of the Ho{sup 3+} ions of single LiLuF{sub 4} microparticle was boosted about 17-fold, and the output colors were tuned from green to red, which is due to the two efficient cross-relaxation between Ho{sup 3+} and Ce{sup 3+} ions enhances the red and suppresses the green in the emission processes. To investigate the optical properties of the single microparticle or nanoparticle through the confocal microscopy setup can effectively avoid the influence of surrounding particle or environment, and could provide more precise information for better exploring the emission mechanisms of rare earth ions. The tunable upconversion emission of Ho{sup 3+} in single LiLuF{sub 4} microparticle in this work will have great potential applications in the micro optoelectronic devices and color display applications. - Highlights: • The optical properties of the single LiLuF4: Yb3+/Ho3+/Ce3+ microparticle were studied. • The output colors of single LiLuF4 microparticle were tuned from green to red. • The upconversion mechanisms between Ho3+ and Ce3+ ions were discussed based on emission spectrum.

  19. Experimental validation of single pass ion cyclotron resonance absorption in a high speed flowing plasma applied to the variable specific impulse magnetoplasma rocket (VASIMR)

    Science.gov (United States)

    Davis, Christopher Nelson

    The topic of this thesis is the experimental characterization and analysis of single pass ion cyclotron resonance heating as applied to acceleration of ions for electric propulsion. The experimental work was done on the VX-10 experiment of the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) concept. In ion cyclotron resonance heating (ICRH) a RF wave is launched into a magnetized plasma where it then accelerates the ions by increasing their rotational speed around the magnetic field lines. The electric field vector of the right hand component of the wave will rotate around the field lines with a frequency oRF in the same direction as the ion's cyclotron motion about the field lines. Consequently, when oRF ≈ oci (where oci is the ion's cyclotron frequency) the force from the electric field of the wave on the ions will result in a continuous rotational energy gain. The perpendicular velocity of the ions generated by ICRH is then converted into axial velocity by the decreasing gradient of the axial magnetic field at the exhaust of the propulsion system from conservation of the magnet moment. This increase in axial velocity is predicted to cause a decrease in density due to conservation of current in the plasma. In order to characterize this density drop during ion cyclotron heating, a single channel interferometer system was developed and implemented on the VX-10. Interferometer density measurements were taken at three different locations on the VX-10 experiment upstream and downstream of the ion acceleration zone. Measurements were made of the density drop in both Helium and Deuterium plasma discharges during ICRH under a variety of operating conditions including magnetic field profile, gas flow rate and ICRH power pulse timing, and ICRH power. A clear measurement of a density drop was observed downstream of the ion resonance zone characteristic of ion acceleration and measurement of little change in density upstream of the resonance zone where no

  20. Dy3+ ions doped single and mixed alkali fluoro tungsten tellurite glasses for LASER and white LED applications

    Science.gov (United States)

    Annapurna Devi, Ch. B.; Mahamuda, Sk.; Venkateswarlu, M.; Swapna, K.; Srinivasa Rao, A.; Vijaya Prakash, G.

    2016-12-01

    A new-fangled series of Dy3+ ions doped Single and Mixed Alkali Fluoro Tungsten Tellurite Glasses have been prepared by using melt quenching technique and their spectroscopic behaviour was investigated by using XRD, optical absorption, photoluminescence and lifetime measurements. The bonding parameter studies reveal the ionic nature of the Dysbnd O bond in the present glasses. From the absorption spectra, the Judd-Ofelt (J-O) intensity parameters have been determined and in turn used to determine various radiative properties for the different emission transitions from the 4F9/2 fluorescent level. The photoluminescence spectra of all the glasses exhibit two intensified peaks in blue and yellow regions corresponding to the transitions 4F9/2 → 6H15/2 (483 nm) and 4F9/2 → 6H13/2 (575 nm) respectively. From the photoluminescence spectra, it is observed that the luminescence intensity is maximum for Dy3+ ion doped potassium combination of tungsten tellurite glass (TeWK:1Dy). The highest emission cross-section and branching ratio values observed for the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions suggest the possible laser action in the visible region from these glasses. By correlating the experimental lifetimes (τexp) measured from the decay spectral features with radiative lifetimes (τR), the quantum efficiencies (η) for all the glasses have been evaluated and found to be maximum for potassium combination tungsten tellurite (TeWK:1Dy) glass. The CIE colour chromaticity coordinates (x, y), (u, v), colour correlated temperature (CCT) and Y/B ratio were also estimated from the photoluminescence spectra for different compositions of glasses. The chromaticity colour coordinates evaluated for all the glasses fall within the white light region and white light emission can be tuned by varying the composition of the glass. From all these studies, it was concluded that 1 mol% of Dy3+ ions doped TeWK glass is more suitable for lasing and white-LED applications.

  1. Production of a double-humped ion velocity distribution function in a single-ended Q-machine

    DEFF Research Database (Denmark)

    Andersen, S.A.; Jensen, Vagn Orla; Michelsen, Poul

    1970-01-01

    An experimental method of producing a double-humped velocity distribution function for the ions in a Q-machine is described. The method is based on charge exchange processes between neutral ceasium and the ions in a ceasium plasma.......An experimental method of producing a double-humped velocity distribution function for the ions in a Q-machine is described. The method is based on charge exchange processes between neutral ceasium and the ions in a ceasium plasma....

  2. Improving the porosity and catalytic capacity of a zinc paddlewheel metal-organic framework (MOF) through metal-ion metathesis in a single-crystal-to-single-crystal fashion.

    Science.gov (United States)

    Yang, Jie; Wang, Xiaoqing; Dai, Fangna; Zhang, Liangliang; Wang, Rongming; Sun, Daofeng

    2014-10-06

    Zinc paddlewheel metal-organic frameworks (MOFs) frequently exhibit low stability or complete collapse upon the removal of axial ligands. Hence, there are very few reports on gas adsorption of zinc paddlewheel MOFs. In this work, the N2 and H2 adsorption measurements were carried out for a zinc MOF (namely, SDU-1) based on two types of paddlewheel secondary building units (SBUs): [Zn2(COO)3] and [Zn2(COO)4]. Because of the existence of inherent surface instability upon removal of solvates in zinc paddlewheel SBU, SDU-1 possesses a very low surface area. Through metal-ion metathesis in a single-crystal-to-single-crystal fashion, the Zn(2+) ions in SDU-1 were exchanged by Cu(2+) ions to generate Cu-SDU-1. Through the measurements of gas adsorption and catalytic test, the porosity and catalytic capacity of Cu-SDU-1 have been improved significantly, compared to SDU-1.

  3. Erratum : Critical Properties of Spin-1 Antiferromagnetic Heisenberg Chains with Bond Alternation and Uniaxial Single-Ion-Type Anisotropy (vol 69, pg 237, 2000)

    OpenAIRE

    飛田, 和男

    2008-01-01

    Original Paper :Critical Properties of Spin-1 Antiferromagnetic Heisenberg Chains with Bond Alternation and Uniaxial Single-Ion-Type AnisotropyWei Chen, Kazuo Hida and Bryan Clifford Sanctuary Journal of the Physical Society of Japan 69 (2000) pp.237-241

  4. Attraction between neutral dielectrics mediated by multivalent ions in an asymmetric ionic fluid

    Science.gov (United States)

    Kanduč, Matej; Naji, Ali; Forsman, Jan; Podgornik, Rudolf

    2012-11-01

    We study the interaction between two neutral plane-parallel dielectric bodies in the presence of a highly asymmetric ionic fluid, containing multivalent as well as monovalent (salt) ions. Image charge interactions, due to dielectric discontinuities at the boundaries, as well as effects from ion confinement in the slit region between the surfaces are taken fully into account, leading to image-generated depletion attraction, ion correlation attraction, and steric-like repulsive interactions. We investigate these effects by employing a combination of Monte Carlo simulation methods, including explicit-ion simulations (where all electrostatic interactions are simulated explicitly) and implicit-ion simulations (where monovalent ions are replaced by an effective screened electrostatic potential between multivalent ions), as well as an approximate analytical theory. The latter incorporates strong ion-image charge correlations, which develop in the presence of high valency ions in the mixture. We show that the implicit-ion simulations and the proposed analytical theory can describe the explicit simulation results on a qualitative level, while excellent quantitative agreement can be obtained for sufficiently large monovalent salt concentrations. The resultant attractive interaction between the neutral surfaces is shown to be significant, as compared with the usual van der Waals interactions between semi-infinite dielectrics, and can thus play an important role at the nano scale.

  5. Ion selectivity of alpha-hemolysin with a beta-cyclodextrin adapter. I. Single ion potential of mean force and diffusion coefficient.

    Science.gov (United States)

    Luo, Yun; Egwolf, Bernhard; Walters, D Eric; Roux, Benoît

    2010-01-21

    The alpha-hemolysin (alphaHL) is a self-assembling exotoxin that binds to the membrane of a susceptible host cell and causes its death. Experimental studies show that electrically neutral beta-cyclodextrin (betaCD) can insert into the alphaHL channel and significantly increase its anion selectivity. To understand how betaCD can affect ion selectivity, molecular dynamics simulations and potential of mean force (PMF) calculations are carried out for different alphaHL channels with and without the betaCD adapter. A multiscale approach based on the generalized solvent boundary potential is used to reduce the size of the simulated system. The PMF profiles reveal that betaCD has no anion selectivity by itself but can increase the Cl(-) selectivity of the alphaHL channel when lodged into the pore lumen. Analysis shows that betaCD causes a partial desolvation of ions and affects the orientation of nearby charged residues. The ion selectivity appears to result from increased electrostatic interaction between the ion and the channel due to a reduction in dielectric shielding by the solvent. These observations suggest a reasonable explanation of the ion selectivity and provide important information for further ion channel modification.

  6. Computation of methodology-independent single-ion solvation properties from molecular simulations. III. Correction terms for the solvation free energies, enthalpies, entropies, heat capacities, volumes, compressibilities, and expansivities of solvated ions.

    Science.gov (United States)

    Reif, Maria M; Hünenberger, Philippe H

    2011-04-14

    The raw single-ion solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions (finite or periodic system, system or box size) and treatment of electrostatic interactions (Coulombic, lattice-sum, or cutoff-based) used during these simulations. However, as shown by Kastenholz and Hünenberger [J. Chem. Phys. 124, 224501 (2006)], correction terms can be derived for the effects of: (A) an incorrect solvent polarization around the ion and an incomplete or/and inexact interaction of the ion with the polarized solvent due to the use of an approximate (not strictly Coulombic) electrostatic scheme; (B) the finite-size or artificial periodicity of the simulated system; (C) an improper summation scheme to evaluate the potential at the ion site, and the possible presence of a polarized air-liquid interface or of a constraint of vanishing average electrostatic potential in the simulated system; and (D) an inaccurate dielectric permittivity of the employed solvent model. Comparison with standard experimental data also requires the inclusion of appropriate cavity-formation and standard-state correction terms. In the present study, this correction scheme is extended by: (i) providing simple approximate analytical expressions (empirically-fitted) for the correction terms that were evaluated numerically in the above scheme (continuum-electrostatics calculations); (ii) providing correction terms for derivative thermodynamic single-ion solvation properties (and corresponding partial molar variables in solution), namely, the enthalpy, entropy, isobaric heat capacity, volume, isothermal compressibility, and isobaric expansivity (including appropriate standard-state correction terms). The ability of the correction scheme to produce methodology-independent single-ion solvation free energies based on atomistic simulations is tested in the case of Na(+) hydration, and the nature and magnitude of the correction terms for

  7. Surfactants at Single-Walled Carbon Nanotube-Water Interface: Physics of Surfactants, Counter-Ions, and Hydration Shell

    Science.gov (United States)

    Khare, Ketan S.; Phelan, Frederick R., Jr.

    Specialized applications of single-walled carbon nanotubes (SWCNTs) require an efficient and reliable method to sort these materials into monodisperse fractions with respect to their defining metrics (chirality, length, etc.) while retaining their physical and chemical integrity. A popular method to achieve this goal is to use surfactants that individually disperse SWCNTs in water and then to separate the resulting colloidal mixture into fractions that are enriched in monodisperse SWCNTs. Recently, experiments at NIST have shown that subtle point mutations of chemical groups in bile salt surfactants have a large impact on the hydrodynamic properties of SWCNT-surfactant complexes during ultracentrifugation. These results provide strong motivation for understanding the rich physics underlying the assembly of surfactants around SWCNTs, the structure and dynamics of counter ions around the resulting complex, and propagation of these effects into the first hydration shell. Here, all-atom molecular dynamics simulations are used to investigate the thermodynamics of SWCNT-bile salt surfactant complexes in water with an emphasis on the buoyant characteristics of the SWCNT-surfactant complexes. Simulation results will be presented along with a comparison with experimental data. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.

  8. Towards ion beam synthesis of single CdSe nanocrystal quantum dots in a SiO{sub 2} matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Hans Moritz; Kinzel, Joerg B.; Krenner, Hubert J. [Emmy Noether Group at Lehrstuhl Experimentalphysik 1, Universitaet Augsburg (Germany); Karl, Helmut [Lehrstuhl Experimentalphysik IV, Universitaet Augsburg (Germany); Wixforth, Achim [Lehrstuhl Experimentalphysik I, Universitaet Augsburg (Germany)

    2013-07-01

    II-VI compound semiconductor quantum dots (QDs) are a promising class of materials for applications in optical devices in the visible spectral domain. Here we show that in addition to traditional fabrication techniques such as molecular beam epitaxy or chemical synthesis, high fluence ion-beam implantation followed by a rapid thermal annealing step, can be readily applied to synthesize CdSe nanocrystals with superior optical properties within the thermal oxide on a Si wafer. In order to confine the implantation volume we employ chromium masks with arrays of nanoscale aperture openings with diameters smaller than 250 nm. We analyzed the such implanted and annealed samples by scanning electron microscopy and micro-photoluminescence spectroscopy. We observe a pronounced broadening and blue shift of the nanocrystal emission when decreasing the aperture diameter to <1000 nm. We attribute this behavior to a reduction of the mean nanocrystal size but increase of its size distribution. For the smallest aperture sizes used we observe a pronounced shell-filling behavior characteristic for single quantum dot nanoemitters.

  9. Exactly solved mixed spin-(1,1/2) Ising–Heisenberg diamond chain with a single-ion anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Lisnyi, Bohdan, E-mail: lisnyj@icmp.lviv.ua [Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 040 01 Košice (Slovakia); Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Street, 79011 L' viv (Ukraine); Strečka, Jozef, E-mail: jozef.strecka@upjs.sk [Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 040 01 Košice (Slovakia)

    2015-03-01

    The mixed spin-(1,1/2) Ising–Heisenberg diamond chain with a single-ion anisotropy is exactly solved through the generalized decoration–iteration transformation and the transfer-matrix method. The decoration–iteration transformation is first used for establishing a rigorous mapping equivalence with the corresponding spin-1 Blume–Emery–Griffiths chain, which is subsequently exactly treated within the transfer-matrix technique. Apart from three classical ground states the model exhibits three striking quantum ground states in which a singlet-dimer state of the interstitial Heisenberg spins is accompanied either with a frustrated state or a polarized state or a non-magnetic state of the nodal Ising spins. It is evidenced that two magnetization plateaus at zero and/or one-half of the saturation magnetization may appear in low-temperature magnetization curves. The specific heat may display remarkable temperature dependences with up to three and four distinct round maxima in a zero and non-zero magnetic field, respectively. - Highlights: • Mixed spin-(1,1/2) Ising–Heisenberg diamond chain is exactly solved. • Quantum ground states with a singlet-dimer state of the Heisenberg spins are found. • Magnetization curve displays intermediate plateaus at zero and half of full magnetization. • Thermal dependences of specific heat may display up to four distinct peaks.

  10. Critical Properties of the Bond-Diluted Mixed Transverse Ising Spin System with Single-Ion Anisotropy

    Institute of Scientific and Technical Information of China (English)

    YAN ShiLei; DENG LingLing; YANG ChuanZhang

    2001-01-01

    The critical properties of the bond-diluted mixed spin-1/2 and spin-1 transverse Ising system with singleion anisotropy are investigated by means of the effective field theory with correlations. Particular emphasis is given to the square lattice for which phase diagrams are obtained. If transverse field varies in the certain ranges we find that the tricritical point is obtained for the value of the bond concentration in a restricted region. We also observe that the reentrant phase transition may occur in the present system if single-ion anisotropy parameter is not large and if transverse field is small. On the other hand, for certain values of the system parameters, new induced magnetic ordering can be obtained. We find a number of interesting phenomena that are not predicted by previous literatures. The influence of the transverse field on the behaviours of the reentrant phase transition and induced magnetic ordering is discussed. A detailed description of the phase transition is presented.``

  11. A mixed-valence metallogrid [CoCo] with an unusual electronic structure and single-ion-magnet characterization.

    Science.gov (United States)

    Huang, Wei; Pan, Feifei; Wang, Zhenxing; Bai, Yan; Feng, Xuejun; Gu, Jiande; Ouyang, Zhong-Wen; Wu, Dayu

    2017-04-11

    The reaction of the multisite coordination ligand (H2L) with Co(Ac)2·4H2O in the absence of any base affords a homometallic tetranuclear mixed-valence complex, [Co4(L)4(CH3CO2)2(CH3OH)2]·Et2O (1). This mixed-valence metallogrid [Co4(L)4(CH3CO2)2 (CH3OH)2]·Et2O (1) has been theoretically and experimentally analyzed to assign the valence and spin state in the form of trans-[Co-Co-Co-Co]. HF-EPR reveals the presence of axial anisotropy (D = -34.4 cm(-1)) with a significant transverse component (E = 9.5 cm(-1)) in the local high spin cobalt centers. Slow magnetic relaxation effects were observed in the presence of a dc field, demonstrating field-induced single ion magnetic behavior, which is associated with the unusual electronic structure of Co(ii) within the metallogrid.

  12. On the structural origin of the single-ion magnetic anisotropy in LuFeO 3

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shi; Zhang, Xiaozhe; Paudel, Tula R.; Sinha, Kishan; Wang, Xiao; Jiang, Xuanyuan; Wang, Wenbin; Brutsche, Stuart; Wang, Jian; Ryan, Philip J.; Kim, Jong-Woo; Cheng, Xuemei; Tsymbal, Evgeny Y.; Dowben, Peter A.; Xu, Xiaoshan

    2016-03-16

    The electronic structure for the conduction bands of both hexagonal and orthorhombic LuFeO3 thin films have been measured using x-ray absorption spectroscopy at oxygen K (O K) edge. Dramatic differences in both the spectral features and the linear dichroism are observed. These differences in the spectra can be explained using the differences in crystal field splitting of the metal (Fe and Lu) electronic states and the differences in O 2p-Fe 3d and O 2p-Lu 5d hybridizations. While the oxidation states have not changed, the spectra are sensitive to the changes in the local environments of the Fe3+ and Lu3+ sites in the hexagonal and orthorhombic structures. Using the crystal-field splitting and the hybridizations that are extracted from the measured electronic structures and the structural distortion information, we derived the occupancies of the spin minority states in Fe3+, which are non-zero and uneven. The single ion anisotropy on Fe3+ sites is found to originate from these uneven occupancies of the spin minority states via spin–orbit coupling in LuFeO3.

  13. Development of an Ion Chromatography Method for Analysis of Organic Anions (Fumarate, Oxalate, Succinate, and Tartrate) in Single Chromatographic Conditions.

    Science.gov (United States)

    Kaviraj, Yarbagi; Srikanth, B; Moses Babu, J; Venkateswara Rao, B; Paul Douglas, S

    2015-01-01

    A single organic counterion analysis method was developed by using an ion chromatography separation technique and conductivity detector. This allows the rapid characterization of an API to support clinical studies and to fulfil the regulatory requirements for the quantitation of fumarate, oxalate, succinate, and tartrate counterions in active pharmaceutical ingredients (quetiapine fumarate, escitalopram oxalate, sumatriptan succinate, and tolterodine tartrate). The method was developed by using the Metrohm Metrosep A Supp 1 (250 × 4.0 mm, 5.0 µm particle size) column with a mobile phase containing an isocratic mixture of solution A: 7.5 mM sodium carbonate and 2.0 mM sodium bicarbonate in Milli-Q water and solution B: acetonitrile. The flow rate was set at 1.0 mL/min and the run time was 25 minutes. The developed method was validated as per ICH guidelines, and the method parameters were chosen to ensure the spontaneous quantitation of all four anions. The method was validated for all four anions to demonstrate the applicability of this method to common anions present in various APIs.

  14. A photoluminescence study of CuInSe2 single crystals ion implanted with 5 keV hydrogen

    Science.gov (United States)

    Yakushev, M. V.; Krustok, J.; Grossberg, M.; Volkov, V. A.; Mudryi, A. V.; Martin, R. W.

    2016-03-01

    CuInSe2 single crystals ion implanted with 5 keV hydrogen at doses from 3  ×  1014 to 1016 cm-2 are studied by photoluminescence (PL). The PL spectra before and after implantation reveal two bands, a main dominant band centred at 0.96 eV and a lower intensity band centred at 0.93 eV. Detailed analysis of the shape of these bands, their temperature and excitation intensity dependencies allow the recombination mechanisms to be identified as band-to-tail (BT) and band-to-impurity (BI), respectively. The implantation causes gradual red shifts of the bands increasing linearly with the dose. The average depth of potential fluctuations is also estimated to increase with the dose and saturates for doses above 1015 cm-2. A model is proposed which associates the potential fluctuations with the antisite defects copper on indium site and indium on copper site. The saturation is explained by full randomization of copper and indium atoms on the cation sub-lattice.

  15. Metal-Organic Frameworks (MOFs) as Multivalent Materials: Size Control and Surface Functionalization by Monovalent Capping Ligands.

    Science.gov (United States)

    Rijnaarts, Timon; Mejia-Ariza, Raquel; Egberink, Richard J M; van Roosmalen, Wies; Huskens, Jurriaan

    2015-07-13

    Control over particle size and composition are pivotal to tune the properties of metal organic frameworks (MOFs), for example, for biomedical applications. Particle-size control and functionalization of MIL-88A were achieved by using stoichiometric replacement of a small fraction of the divalent fumarate by monovalent capping ligands. A fluorine-capping ligand was used to quantify the surface coverage of capping ligand at the surface of MIL-88A. Size control at the nanoscale was achieved by using a monovalent carboxylic acid-functionalized poly(ethylene glycol) (PEG-COOH) ligand at different concentrations. Finally, a biotin-carboxylic acid capping ligand was used to functionalize MIL-88A to bind fluorescently labeled streptavidin as an example towards bioapplications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Higher cytotoxicity of divalent antibody-toxins than monovalent antibody-toxins

    Energy Technology Data Exchange (ETDEWEB)

    Won, JaeSeon; Nam, PilWon; Lee, YongChan [College of Life Sciences and Graduate School of Biotechnology, Korea University, 5-ga Anam-dong, Sungbuk-gu, Seoul 136-701 (Korea, Republic of); Choe, MuHyeon, E-mail: choemh@korea.ac.kr [College of Life Sciences and Graduate School of Biotechnology, Korea University, 5-ga Anam-dong, Sungbuk-gu, Seoul 136-701 (Korea, Republic of)

    2009-04-24

    Recombinant antibody-toxins are constructed via the fusion of a 'carcinoma-specific' antibody fragment to a toxin. Due to the high affinity and high selectivity of the antibody fragments, antibody-toxins can bind to surface antigens on cancer cells and kill them without harming normal cells [L.H. Pai, J.K. Batra, D.J. FitzGerald, M.C. Willingham, I. Pastan, Anti-tumor activities of immunotoxins made of monoclonal antibody B3 and various forms of Pseudomonas exotoxin, Proc. Natl. Acad. Sci. USA 88 (1991) 3358-3362]. In this study, we constructed the antibody-toxin, Fab-SWn-PE38, with SWn (n = 3, 6, 9) sequences containing n-time repeated (G{sub 4}S) between the Fab fragment and PE38 (38 kDa truncated form of Pseudomonas exotoxin A). The SWn sequence also harbored one cysteine residue that could form a disulfide bridge between two Fab-SWn-PE38 monomers. We assessed the cytotoxicity of the monovalent (Fab-SWn-PE38), and divalent ([Fab-SWn-PE38]{sub 2}) antibody-toxins. The cytotoxicity of the dimer against the CRL1739 cell line was approximately 18.8-fold higher than that of the monomer on the ng/ml scale, which was approximately 37.6-fold higher on the pM scale. These results strongly indicate that divalency provides higher cytotoxicity for an antibody-toxin.

  17. Independent adsorption of monovalent cations and cationic polymers at PE/PG lipid membranes

    Science.gov (United States)

    Khomich, Daria A.; Nesterenko, Alexey M.; Kostritskii, Andrei Yu; Kondinskaia, Diana A.; Ermakov, Yuri A.; Gurtovenko, Andrey A.

    2017-01-01

    Synthetic cationic polymers constitute a wide class of polymeric biocides. Commonly their antimicrobial effect is associated to their interaction with bacterial membranes. In the present study we analyze the interaction of various cationic polymers with model bacterial membranes comprised of a mixture of phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). We describe a polymer-membrane interaction as a process of modification of the surface charge. It is well known that small monovalent inorganic cations (Na+, K+) cannot overcharge the surface of a bilayer containing anionic lipids. In contrast, polycations are able to overcharge anionic membranes and demonstrate a very large input to the electric field distribution at the membrane-water interface. We aimed here to study the electrostatic effects associated with the interaction of polycations of different types with a model lipid membrane whose composition closely resembles that of bacterial membranes (PE:PG = 1:4). Four different cationic polymers (polyvinylamine, polyallylamine, poly-L-lysine and polyethylenimine) were adsorbed at a model PE/PG bilayer in MD simulations. Adsorption of sodium cations was inspected separately for PE/PG bilayers of different composition and cation’s binding parameters were determined. From computational experiments and consequent theoretical analysis we concluded that sodium adsorption at anionic binding sites does not depend on the presence of polycations. Therefore, we hypothesize that antimicrobial activity of the studied cationic polymers should depend on the ionic composition of the medium.

  18. Antigenic specificity of a monovalent versus polyvalent MOMP based Chlamydia pecorum vaccine in koalas (Phascolarctos cinereus).

    Science.gov (United States)

    Kollipara, Avinash; Wan, Charles; Rawlinson, Galit; Brumm, Jacqui; Nilsson, Karen; Polkinghorne, Adam; Beagley, Kenneth; Timms, Peter

    2013-02-06

    Chlamydia continues to be a major pathogen of koalas. The bacterium is associated with ocular, respiratory and urogenital tract infections and a vaccine is considered the best option to limit the decline of mainland koala populations. Over the last 20 years, efforts to develop a chlamydial vaccine in humans have focussed on the use of the chlamydial major outer membrane protein (MOMP). Potential problems with the use of MOMP-based vaccines relate to the wide range of genetic diversity in its four variable domains. In the present study, we evaluated the immune response of koalas vaccinated with a MOMP-based C. pecorum vaccine formulated with genetically and serologically diverse MOMPs. Animals immunised with individual MOMPs developed strong antibody and lymphocyte proliferation responses to both homologous as well as heterologous MOMP proteins. Importantly, we also showed that vaccine induced antibodies which effectively neutralised various heterologous strains of koala C. pecorum in an in vitro assay. Finally, we also demonstrated that the immune responses in monovalent as well as polyvalent MOMP vaccine groups were able to recognise whole chlamydial elementary bodies, illustrating the feasibility of developing an effective MOMP based C. pecorum vaccine that could protect against a range of strains. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  19. Impact of universal mass vaccination with monovalent inactivated hepatitis A vaccines – A systematic review

    Science.gov (United States)

    Stuurman, Anke L.; Marano, Cinzia; Bunge, Eveline M.; De Moerlooze, Laurence; Shouval, Daniel

    2017-01-01

    ABSTRACT The WHO recommends integration of universal mass vaccination (UMV) against hepatitis A virus (HAV) in national immunization schedules for children aged ≥1 year, if justified on the basis of acute HAV incidence, declining endemicity from high to intermediate and cost-effectiveness. This recommendation has been implemented in several countries. Our aim was to assess the impact of UMV using monovalent inactivated hepatitis A vaccines on incidence and persistence of anti-HAV (IgG) antibodies in pediatric populations. We conducted a systematic review of literature published between 2000 and 2015 in PubMed, Cochrane Library, LILACS, IBECS identifying a total of 27 studies (Argentina, Belgium, China, Greece, Israel, Panama, the United States and Uruguay). All except one study showed a marked decline in the incidence of hepatitis A post introduction of UMV. The incidence in non-vaccinated age groups decreased as well, suggesting herd immunity but also rising susceptibility. Long-term anti-HAV antibody persistence was documented up to 17 y after a 2-dose primary vaccination. In conclusion, introduction of UMV in countries with intermediate endemicity for HAV infection led to a considerable decrease in the incidence of hepatitis A in vaccinated and in non-vaccinated age groups alike. PMID:27786671

  20. Monovalency Unleashes the Full Therapeutic Potential of the DN-30 Anti-Met Antibody*

    Science.gov (United States)

    Pacchiana, Giovanni; Chiriaco, Cristina; Stella, Maria C.; Petronzelli, Fiorella; De Santis, Rita; Galluzzo, Maria; Carminati, Paolo; Comoglio, Paolo M.; Michieli, Paolo; Vigna, Elisa

    2010-01-01

    Met, the high affinity receptor for hepatocyte growth factor, is one of the most frequently activated tyrosine kinases in human cancer and a validated target for cancer therapy. We previously developed a mouse monoclonal antibody directed against the extracellular portion of Met (DN-30) that induces Met proteolytic cleavage (receptor “shedding”) followed by proteasome-mediated receptor degradation. This translates into inhibition of hepatocyte growth factor/Met-mediated biological activities. However, DN-30 binding to Met also results in partial activation of the Met kinase due to antibody-mediated receptor homodimerization. To safely harness the therapeutic potential of DN-30, its shedding activity must be disassociated from its agonistic activity. Here we show that the DN-30 Fab fragment maintains high affinity Met binding, elicits efficient receptor shedding and down-regulation, and does not promote kinase activation. In Met-addicted tumor cell lines, DN-30 Fab displays potent cytostatic and cytotoxic activity in a dose-dependent fashion. DN-30 Fab also inhibits anchorage-independent growth of several tumor cell lines. In mouse tumorigenesis assays using Met-addicted carcinoma cells, intratumor administration of DN-30 Fab or systemic delivery of a chemically stabilized form of the same molecule results in reduction of Met phosphorylation and inhibition of tumor growth. These data provide proof of concept that monovalency unleashes the full therapeutic potential of the DN-30 antibody and point at DN-30 Fab as a promising tool for Met-targeted therapy. PMID:20833723

  1. Monovalency unleashes the full therapeutic potential of the DN-30 anti-Met antibody.

    Science.gov (United States)

    Pacchiana, Giovanni; Chiriaco, Cristina; Stella, Maria C; Petronzelli, Fiorella; De Santis, Rita; Galluzzo, Maria; Carminati, Paolo; Comoglio, Paolo M; Michieli, Paolo; Vigna, Elisa

    2010-11-12

    Met, the high affinity receptor for hepatocyte growth factor, is one of the most frequently activated tyrosine kinases in human cancer and a validated target for cancer therapy. We previously developed a mouse monoclonal antibody directed against the extracellular portion of Met (DN-30) that induces Met proteolytic cleavage (receptor "shedding") followed by proteasome-mediated receptor degradation. This translates into inhibition of hepatocyte growth factor/Met-mediated biological activities. However, DN-30 binding to Met also results in partial activation of the Met kinase due to antibody-mediated receptor homodimerization. To safely harness the therapeutic potential of DN-30, its shedding activity must be disassociated from its agonistic activity. Here we show that the DN-30 Fab fragment maintains high affinity Met binding, elicits efficient receptor shedding and down-regulation, and does not promote kinase activation. In Met-addicted tumor cell lines, DN-30 Fab displays potent cytostatic and cytotoxic activity in a dose-dependent fashion. DN-30 Fab also inhibits anchorage-independent growth of several tumor cell lines. In mouse tumorigenesis assays using Met-addicted carcinoma cells, intratumor administration of DN-30 Fab or systemic delivery of a chemically stabilized form of the same molecule results in reduction of Met phosphorylation and inhibition of tumor growth. These data provide proof of concept that monovalency unleashes the full therapeutic potential of the DN-30 antibody and point at DN-30 Fab as a promising tool for Met-targeted therapy.

  2. Experimental research of heavy ion and proton induced single event effects for a Bi-CMOS technology DC/DC converter

    Science.gov (United States)

    Anlin, He; Gang, Guo; Shuting, Shi; Dongjun, Shen; Jiancheng, Liu; Li, Cai; Hui, Fan

    2015-11-01

    This paper tested and analyzed heavy ion and proton induced single event effects (SEE) of a commercial DC/DC converter based on a 600 nm Bi-CMOS technology. Heavy ion induced single event transients (SET) testing has been carried out by using the Beijing HI-13 tandem accelerator at China Institute of Atomic Energy. Proton test has been carried out by using the Canadian TRIUMF proton accelerator. Both SET cross section versus linear energy transfer (LET) and proton energy has been measured. The main study conclusions are: (1) the DC/DC is both sensitive to heavy ion and proton radiations although at a pretty large feature size (600 nm), and threshold LET is about 0.06 MeV·mg/cm2 (2) heavy ion SET saturation cross section is about 5 magnitudes order larger than proton SET saturation cross section, which is consistent with the theory calculation result deduced by the RPP model and the proton nuclear reaction model; (3) on-orbit soft error rate (SER) prediction showed, on GEO orbit, proton induced SERs calculated by the heavy ion derived model are 4-5 times larger than those calculated by proton test data.

  3. Synthesis, crystal growth, structural, spectral, thermal, mechanical, linear and nonlinear optical studies of organic single crystal 4-Iodo 4-nitrostilbene (IONS): A potential NLO material

    Energy Technology Data Exchange (ETDEWEB)

    Dinakaran, Paul M.; Kalainathan, S., E-mail: kalainathan@yahoo.com

    2013-12-16

    An organic nonlinear optical material 4-Iodo 4-nitrostilbene (IONS) has been synthesized and good optical quality single crystal was grown from ethyl methyl ketone solvent by the solution growth technique. Single and powder X-ray diffraction analyses reveals that the grown crystal belongs to monoclinic crystal system with noncentrosymmetric space group ‘P2{sub 1}’ and it has good crystalline nature. Functional groups and molecular structure of the title compound were confirmed by FTIR and {sup 1}H NMR respectively. The UV–Vis–NIR absorption study reveals no absorption in the visible region and the cut-off wavelength was found to be at 412.84 nm, TG/DTA, mass spectral analysis, photoluminescence and microhardness studies have been carried out for the grown crystals and results are discussed in detail. The second harmonic efficiency of the IONS was determined by Kurtz–Perry powder technique which reveals that the IONS crystal (3.1 V) has greater efficiency i.e., 143 times to that of KDP (21.7 mV). - Highlights: • The 4-Iodo 4-nitrostilbene (IONS) material has been synthesized by Wittig reaction. • The single crystal was grown for the first time with dimensions of 9.5 × 4 × 1.5 mm{sup 3}. • SHG efficiency of IONS is 143 times greater than that of KDP crystal. • The UV–Vis absorption study reveals that the transparency was found to be good. • IONS crystal is a potential candidate for optoelectronic applications.

  4. Magnetic properties of weakly exchange-coupled high spin Co(II) ions in pseudooctahedral coordination evaluated by single crystal X-band EPR spectroscopy and magnetic measurements.

    Science.gov (United States)

    Neuman, Nicolás I; Winkler, Elín; Peña, Octavio; Passeggi, Mario C G; Rizzi, Alberto C; Brondino, Carlos D

    2014-03-01

    We report single-crystal X-band EPR and magnetic measurements of the coordination polymer catena-(trans-(μ2-fumarato)tetraaquacobalt(II)), 1, and the Co(II)-doped Zn(II) analogue, 2, in different Zn:Co ratios. 1 presents two magnetically inequivalent high spin S = 3/2 Co(II) ions per unit cell, named A and B, in a distorted octahedral environment coordinated to four water oxygen atoms and trans coordinated to two carboxylic oxygen atoms from the fumarate anions, in which the Co(II) ions are linked by hydrogen bonds and fumarate molecules. Magnetic susceptibility and magnetization measurements of 1 indicate weak antiferromagnetic exchange interactions between the S = 3/2 spins of the Co(II) ions in the crystal lattice. Oriented single crystal EPR experiments of 1 and 2 were used to evaluate the molecular g-tensor and the different exchange coupling constants between the Co(II) ions, assuming an effective spin S′= 1/2. Unexpectedly, the eigenvectors of the molecular g-tensor were not lying along any preferential bond direction, indicating that, in high spin Co(II) ions in roughly octahedral geometry with approximately axial EPR signals, the presence of molecular pseudo axes in the metal site does not determine preferential directions for the molecular g-tensor. The EPR experiment and magnetic measurements, together with a theoretical analysis relating the coupling constants obtained from both techniques, allowed us to evaluate selectively the exchange coupling constant associated with hydrogen bonds that connect magnetically inequivalent Co(II) ions (|JAB(1/2)| = 0.055(2) cm(–1)) and the exchange coupling constant associated with a fumarate bridge connecting equivalent Co(II) ions (|JAA(1/2)| ≈ 0.25 (1) cm(–1)), in good agreement with the average J(3/2) value determined from magnetic measurements.

  5. Measurement of Uranium Isotopes in Particles of U3O8 by Secondary Ion Mass Spectrometry-Single-Stage Accelerator Mass Spectrometry (SIMS-SSAMS).

    Science.gov (United States)

    Fahey, Albert J; Groopman, Evan E; Grabowski, Kenneth S; Fazel, Kamron C

    2016-07-19

    A commercial secondary ion mass spectrometer (SIMS) was coupled to a ± 300 kV single-stage accelerator mass spectrometer (SSAMS). Positive secondary ions generated with the SIMS were injected into the SSAMS for analysis. This combined instrument was used to measure the uranium isotopic ratios in particles of three certified reference materials (CRM) of uranium, CRM U030a, CRM U500, and CRM U850. The ability to inject positive ions into the SSAMS is unique for AMS systems and allows for simple analysis of nearly the entire periodic table because most elements will readily produce positive ions. Isotopic ratios were measured on samples of a few picograms to nanograms of total U. Destruction of UH(+) ions in the stripper tube of the SSAMS reduced hydride levels by a factor of ∼3 × 10(4) giving the UH(+)/U(+) ratio at the SSAMS detector of ∼1.4 × 10(-8). These hydride ion levels would allow the measurement of (239)Pu at the 10 ppb level in the presence of U and the equivalent of ∼10(-10 236)U concentration in natural uranium. SIMS-SSAMS analysis of solid nuclear materials, such as these, with signals nearly free of molecular interferences, could have a significant future impact on the way some measurements are made for nuclear nonproliferation.

  6. A Robust Scheme for Two-Qubit Grover Quantum Search Alogrithm Based on the Motional and Internal States of a Single Cold Trapped Ion

    Institute of Scientific and Technical Information of China (English)

    秦涛; 高克林

    2003-01-01

    We propose a scheme to implement a two-qubit Grover quantum search algorithm.The novelty in the proposal is that the motional state is introduced into the computation and the internal state within a single cold trapped ion.The motional and internal states of the ion are manipulated as two qubits by the laser pulses to accomplish an example of a Grover algorithm based on the two qubits.The composite laser pulses that are applied to implement the Grover algorithm have been designed in detail.The issues concerning measurement and decoherence are discussed.

  7. Two-dimensional coordination polymers constructed using, simultaneously, linear and angular spacers and cobalt(II) nodes. New examples of networks of single-ion magnets.

    Science.gov (United States)

    Ion, Adrian E; Nica, Simona; Madalan, Augustin M; Shova, Sergiu; Vallejo, Julia; Julve, Miguel; Lloret, Francesc; Andruh, Marius

    2015-01-01

    Two novel bidimensional coordination polymers, [Co(azbbpy)(4,4'-bipy)0.5(DMF)(NCS)2]·MeOH (1) and [Co(azbbpy)(bpe)0.5(DMF)(NCS)2]·0.25H2O (2), resulted from the assembling of cobalt(II) ions by 1,3-bis(4-pyridyl)azulene, using either 4,4'-bipyridyl or 1,2-bis(4-pyridyl)ethylene as neutral spacers. The cobalt(II) nodes in 1 and 2 act as single-ion magnets (SIMs).

  8. Divalent Metal Ion Transport across Large Biological Ion Channels and Their Effect on Conductance and Selectivity

    Directory of Open Access Journals (Sweden)

    Elena García-Giménez

    2012-01-01

    Full Text Available Electrophysiological characterization of large protein channels, usually displaying multi-ionic transport and weak ion selectivity, is commonly performed at physiological conditions (moderate gradients of KCl solutions at decimolar concentrations buffered at neutral pH. We extend here the characterization of the OmpF porin, a wide channel of the outer membrane of E. coli, by studying the effect of salts of divalent cations on the transport properties of the channel. The regulation of divalent cations concentration is essential in cell metabolism and understanding their effects is of key importance, not only in the channels specifically designed to control their passage but also in other multiionic channels. In particular, in porin channels like OmpF, divalent cations modulate the efficiency of molecules having antimicrobial activity. Taking advantage of the fact that the OmpF channel atomic structure has been resolved both in water and in MgCl2 aqueous solutions, we analyze the single channel conductance and the channel selectivity inversion aiming to separate the role of the electrolyte itself, and the counterion accumulation induced by the protein channel charges and other factors (binding, steric effects, etc. that being of minor importance in salts of monovalent cations become crucial in the case of divalent cations.

  9. The influence of ions on water transport in nylon 6 films

    NARCIS (Netherlands)

    Reuvers, N.J.W.; Huinink, H.P.; Fischer, H.R.; Adan, O.C.G.

    2013-01-01

    Nylon 6 films are directly exposed to saline solutions containing mono-valent ions and the water uptake is measured with magnetic resonance imaging (MRI). Both the amount of water uptake and the rate of water uptake are studied. First, the films are exposed to solutions with different concentrations

  10. Synthesis of single-crystalline spinel LiMn2 O4 Nanorods for lithium-ion batteries with high rate capability and long cycle life.

    Science.gov (United States)

    Xie, Xiuqiang; Su, Dawei; Sun, Bing; Zhang, Jinqiang; Wang, Chengyin; Wang, Guoxiu

    2014-12-15

    The long-standing challenge associated with capacity fading of spinel LiMn2 O4 cathode material for lithium-ion batteries is investigated. Single-crystalline spinel LiMn2 O4 nanorods were successfully synthesized by a template-engaged method. Porous Mn3 O4 nanorods were used as self-sacrificial templates, into which LiOH was infiltrated by a vacuum-assisted impregnation route. When used as cathode materials for lithium-ion batteries, the spinel LiMn2 O4 nanorods exhibited superior long cycle life owing to the one-dimensional nanorod structure, single-crystallinity, and Li-rich effect. LiMn2 O4 nanorods retained 95.6 % of the initial capacity after 1000 cycles at 3C rate. In particular, the nanorod morphology of the spinel LiMn2 O4 was well-preserved after a long-term cycling, suggesting the ultrahigh structural stability of the single crystalline spinel LiMn2 O4 nanorods. This result shows the promising applications of single-crystalline spinel LiMn2 O4 nanorods as cathode materials for lithium-ion batteries with high rate capability and long cycle life. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Greater hydrogen ion-induced depression of tension and velocity in skinned single fibres of rat fast than slow muscles.

    Science.gov (United States)

    Metzger, J M; Moss, R L

    1987-12-01

    .v.l., suggesting that apparent positive co-operativity of tension development had increased in soleus and decreased in d.v.l. and s.v.l. fibres. 6. These results (1) demonstrate an increased resistance to H+ ion-mediated contractile dysfunction in slow- compared to fast-twitch single fibres, and (2) support the hypothesis that muscular fatigue resulting from short-term, intense muscular contraction may in part be related to elevated H+ ion concentration.

  12. Rapidity-dependent spectra from a single-freeze-out model of relativistic heavy-ion collisions

    Science.gov (United States)

    Biedroń, Bartłomiej; Broniowski, Wojciech

    2007-05-01

    An extension of the single-freeze-out model with thermal and geometric parameters dependent on the spatial rapidity, α∥, is used to describe the rapidity and transverse-momentum spectra of pions, kaons, protons, and antiprotons measured at the Relativistic Heavy Ion Collider at sNN=200GeV by the BRAHMS Collaboration. THERMINATOR is used to perform the necessary simulation, which includes all resonance decays. The result of the fit to the rapidity spectra in the range of the BRAHMS data is the expected growth of the baryon and strange chemical potentials with the magnitude of α∥, whereas the freeze-out temperature is kept fixed. The value of the baryon chemical potential at α∥~3, which is the relevant region for particles detected at the BRAHMS forward rapidity y~3, is about 200GeV, i.e., lies in the range of the values obtained for the highest SPS energy. The chosen geometry of the fireball has a decreasing transverse size as the magnitude of α∥ is increased, which also corresponds to decreasing transverse flow. This feature is verified by reproducing the transverse momentum spectra of pions and kaons at various rapidities. The strange chemical potential obtained from the fit to the K+/K- ratio is such that the local strangeness density in the fireball is compatible with zero. The resulting rapidity spectra of net protons are described qualitatively in the model. As a result of the study, the knowledge of the “topography” of the fireball is achieved, making other calculations possible. As an example, we give predictions for the rapidity spectra of hyperons.

  13. The interplay of long-range magnetic order and single-ion anisotropy in rare earth nickel germanides

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Z.

    1999-05-10

    This dissertation is concerned with the interplay of long-range order and anisotropy in the tetragonal RNi{sub 2}Ge{sub 2} (R = rare earth) family of compounds. Microscopic magnetic structures were studied using both neutron and x-ray resonant exchange scattering (XRES) techniques. The magnetic structures of Tb, Dy, Eu and Gd members have been determined using high-quality single-crystal samples. This work has correlated a strong Fermi surface nesting to the magnetic ordering in the RNi{sub 2}Ge{sub 2} compounds. Generalized susceptibility, {chi}{sub 0}(q), calculations found nesting to be responsible for both incommensurate ordering wave vector in GdNi{sub 2}Ge{sub 2}, and the commensurate structure in EuNi{sub 2}Ge{sub 2}. A continuous transition from incommensurate to commensurate magnetic structures via band filling is predicted. The surprisingly higher T{sub N} in EuNi{sub 2}Ge{sub 2} than that in GdNi{sub 2}Ge{sub 2} is also explained. Next, all the metamagnetic phases in TbNi{sub 2}Ge{sub 2} with an applied field along the c axis have been characterized with neutron diffraction measurements. A mixed phase model for the first metamagnetic structure consisting of fully-saturated as well as reduced-moment Tb ions is presented. The moment reduction may be due to moment instability which is possible if the exchange is comparable to the low-lying CEF level splitting and the ground state is a singlet. In such a case, certain Tb sites may experience a local field below the critical value needed to reach saturation.

  14. Field-Induced Co(II) Single-Ion Magnets with mer-Directing Ligands but Ambiguous Coordination Geometry.

    Science.gov (United States)

    Peng, Yan; Mereacre, Valeriu; Anson, Christopher E; Zhang, Yiquan; Bodenstein, Tilmann; Fink, Karin; Powell, Annie K

    2017-06-05

    Three air-stable Co(II) mononuclear complexes with different aromatic substituents have been prepared and structurally characterized by single-crystal X-ray diffraction. The mononuclear complexes [Co(H2L1)2]·2THF (1), [Co(HL2)2] (2), and [Co(H2L3)2]·CH2Cl2 (3) (where H3L1, H2L2, and H3L3 represent 3-hydroxy-naphthalene-2-carboxylic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, nicotinic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, and 2-hydroxy-benzoic acid (6-hydroxymethyl-pyridin-2-ylmethylene) hydrazide, respectively) feature a distorted mer octahedral coordination geometry. Detailed magnetic studies of 1-3 have been conducted using direct and alternating current magnetic susceptibility data. Field-induced slow magnetic relaxation was observed for these three complexes. There are few examples of such behavior in (distorted) octahedral coordination geometry (OC) Co(II) mononuclear complexes with uniaxial anisotropy. Analysis of the six-coordinate Co(II) mononuclear single-ion magnets (SIMs) in the literature using the SHAPE program revealed that they all show what is best described as distorted trigonal prismatic (TRP) coordination geometry, and in general, these show negative D zero-field splitting (ZFS) values. On the other hand, all the Co(II) mononuclear complexes displaying what is best approximated as distorted octahedral (OC) coordination geometry show positive D values. In the new Co(II) mononuclear complexes we describe here, there is an ambiguity, since the rigid tridentate ligands confer what is best described for an octahedral complex as a mer coordination geometry, but the actual shape of the first coordination sphere is between octahedral and trigonal prismatic. The negative D values observed experimentally and supported by high-level electronic structure calculations are thus in line with a trigonal prismatic geometry. However, a consideration of the rhombicity as indicated by the E value of the ZFS in conjunction with the

  15. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS: A New Tool for the Analysis of Toxicological Effects on Single Cell Level

    Directory of Open Access Journals (Sweden)

    Harald Jungnickel

    2016-02-01

    Full Text Available Single cell imaging mass spectrometry opens up a complete new perspective for strategies in toxicological risk assessment and drug discovery. In particular, time-of-flight secondary ion mass spectrometry (ToF-SIMS with its high spatial and depth resolution is becoming part of the imaging mass spectrometry toolbox used for single cell analysis. Recent instrumentation advancements in combination with newly developed cluster ion guns allow 3-dimensional reconstruction of single cells together with a spatially resolved compound location and quantification on nanoscale depth level. The exact location and quantification of a single compound or even of a set of compounds is no longer restricted to the two dimensional space within single cells, but is available for voxels, a cube-sized 3-dimensional space, rather than pixels. The information gathered from one voxel is further analysed using multivariate statistical methodology like maximum autocorrelation factors to co-locate the compounds of interest within intracellular organelles like nucleus, mitochondria or golgi apparatus. Furthermore, the cell membrane may be resolved, including adhering compounds and potential changes of the lipid patterns. The generated information can be used further for a first evaluation of intracellular target specifity of new drug candidates or for the toxicological risk assessment of environmental chemicals and their intracellular metabolites. Additionally, single cell lipidomics and metabolomics enable for the first time an in-depth understanding of the activation or inhibition of cellular biosynthesis and signalling pathways.

  16. Metal ion trend may be more predictive for malfunctioning metal-on-metal implants than a single measurement

    NARCIS (Netherlands)

    Smolders, J.M.; Hol, A.; Susante, J.L.C. van

    2013-01-01

    Forty-eight unilateral hip resurfacing arthroplasty patients were evaluated for cobalt and chromium levels. The metal ion trend of 42 well-functioning patients was compared with six sub-optimal functioning patients. Median metal ion levels were significantly higher for the sub-optimal group. For the

  17. Optical and electronic properties of single modulation doped GaAs/AlGaAs V-grooved quantum wire modified by ion implantation

    Institute of Scientific and Technical Information of China (English)

    HUANG Shaohua; CHEN Zhanghai; BAI Lihui; WANG Fangzhen; SHEN Xuechu

    2005-01-01

    Single GaAs/Al0.5Ga0.5As V-grooved quantum wire modified by selective ion-implantation and rapid thermally annealing was investigated by spatially-resolved microphotoluminescence and magneto-resistance measurement. Spatially-resolved photoluminescence results indicate that the ion-implantation induced quantum well intermixing raises significantly the electron subband energies of the side quantum wells and vertical quantum wells, and more efficient accumulation of electrons in the quantum wires is achieved. Furthermore, the polarization properties of the photoluminescence from the quantum wires show large linear polarization degree up to 63%. Magneto-transport investigation on the ion implanted quantum wire samples presents the quasi-one dimensional intrinsic motion of electrons, which is important for the design and optimization of one dimensional electronic devices.

  18. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Mohd F., E-mail: faisalt@petronas.com.my; Shaharun, Maizatul S. [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia); Shuib, Anis Suhaila, E-mail: anisuha@petronas.com.my; Borhan, Azry [Chemical Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia)

    2014-10-24

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  19. Paralytic poliomyelitis associated with Sabin monovalent and bivalent oral polio vaccines in Hungary.

    Science.gov (United States)

    Estívariz, Concepción F; Molnár, Zsuzsanna; Venczel, Linda; Kapusinszky, Beatrix; Zingeser, James A; Lipskaya, Galina Y; Kew, Olen M; Berencsi, György; Csohán, Agnes

    2011-08-01

    Historical records of patients with vaccine-associated paralytic poliomyelitis (VAPP) in Hungary during 1961-1981 were reviewed to assess the risk of VAPP after oral polio vaccine (OPV) administration. A confirmed VAPP case was defined as a diagnosis of paralytic poliomyelitis and residual paralysis at 60 days in a patient with an epidemiologic link to the vaccine. Archived poliovirus isolates were retested using polymerase chain reaction and sequencing of the viral protein 1 capsid region. This review confirmed 46 of 47 cases previously reported as VAPP. Three cases originally linked to monovalent OPV (mOPV) 3 and one case linked to mOPV1 presented after administration of bivalent OPV 1 + 3 (bOPV). The adjusted VAPP risk per million doses administered was 0.18 for mOPV1 (2 cases/11.13 million doses), 2.96 for mOPV3 (32 cases/10.81 million doses), and 12.82 for bOPV (5 cases/390,000 doses). Absence of protection from immunization with inactivated poliovirus vaccine or exposure to OPV virus from routine immunization and recent injections could explain the higher relative risk of VAPP in Hungarian children. In polio-endemic areas in which mOPV3 and bOPV are needed to achieve eradication, the higher risk of VAPP would be offset by the high risk of paralysis due to wild poliovirus and higher per-dose efficacy of mOPV3 and bOPV compared with trivalent OPV.

  20. Deposition kinetics of extracellular polymeric substances (EPS) on silica in monovalent and divalent salts.

    Science.gov (United States)

    Zhu, Pingting; Long, Guoyu; Ni, Jinren; Tong, Meiping

    2009-08-01

    The deposition kinetics of extracellular polymeric substances (EPS) on silica surfaces were examined in both monovalent and divalent solutions under a variety of environmentally relevant ionic strength and pH conditions by employing a quartz crystal microbalance with dissipation (DCM-D). Soluble EPS (SEPS) and bound EPS (BEPS) were extracted from four bacterial strains with different characteristics. Maximum favorable deposition rates (k(fa)) were observed for all EPS at low ionic strengths in both NaCl and CaCl2 solutions. With the increase of ionic strength, k(fa) decreased due to the simultaneous occurrence of EPS aggregation in solutions. Deposition efficiency (alpha; the ratio of deposition rates obtained under unfavorable versus corresponding favorable conditions) for all EPS increased with increasing ionic strength in both NaCl and CaCl2 solutions, which agreed with the trends of zeta potentials and was consistent with the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Comparison of alpha for SEPS and BEPS extracted from the same strain showed that the trends of alpha did not totally agree with trends of zeta potentials, indicating the deposition kinetics of EPS on silica surfaces were not only controlled by DLVO interactions, but also non-DLVO forces. Close comparison of alpha for EPS extracted from different sources showed alpha increased with increasing proteins to polysaccharides ratio. Subsequent experiments for EPS extracted from the same strain but with different proteins to polysaccharides ratios and from activated sludge also showed that alpha were largest for EPS with greatest proteins to polysaccharides ratio. Additional experiments for pure protein and solutions with different pure proteins to pure saccharides ratios further corroborated that larger proteins to polysaccharides ratio resulted in greater EPS deposition.

  1. Resonator QED experiments with single {sup 40}Ca{sup +} ions; Resonator-QED-Experimente mit einzelnen {sup 40}Ca{sup +}-Ionen

    Energy Technology Data Exchange (ETDEWEB)

    Lange, B.

    2006-12-20

    Combining an optical resonator with an ion trap provides the possibility for QED experiments with single or few particles interacting with a single mode of the electro-magnetic field (Cavity-QED). In the present setup, fluctuations in the count rate on a time scale below 30 seconds were purely determined by the photon statistics due to finite emission and detection efficiency, whereas a marginal drift of the system was noticeable above 200 seconds. To find methods to increase the efficiency of the photon source, investigations were conducted and experimental improvements of the setup implemented in the frame of this thesis. Damping of the resonator field and coupling of ion and field were considered as the most important factors. To reduce the damping of the resonator field, a resonator with a smaller transmissivity of the output mirror was set up. The linear trap used in the experiment allows for the interaction of multiple ions with the resonator field, so that more than one photon may be emitted per pump pulse. This was investigated in this thesis with two ions coupled to the resonator. The cross correlation of the emitted photons was measured with the Hanbury Brown-Twiss method. (orig.)

  2. Extraction and Analysis of Disperse Dyes from Colored Polyester Single Fibers Using Liquid Chromatography/Linear Ion Trap Tandem Mass Spectrometry.

    Science.gov (United States)

    Kato, Takao; Suzuki, Yasuhiro; Handa, Makoto

    2016-01-01

    Nine disperse dyes extracted from colored polyester threads and single fibers of manufactory-supplied textiles by using centrifugal filtration were analyzed using liquid chromatography/linear ion trap tandem mass spectrometry (LC/LIT-MS(n)). Based on diode array detector data, dimethylformamide (DMF) was found to be a more effective extraction solvent than acetonitrile/water (4:3, v/v) or methanol/water (1:1, v/v) mixtures. The precursor, [M+H](+) ions, were detected for the dyes extracted using DMF. The MS(2) and MS(3) spectra also matched those of the standard disperse dyes. Without relying on comparison clothes, disperse dyes extracted from the single fibers (5 mm in length) were successfully identified by LC/LIT-MS(n) and the custom-built database.

  3. Effects of the single-ion anisotropy on the striped antiferromagnetism of a frustrated Heisenberg model on a stacked square lattice

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Rengui, E-mail: rgzhu@mail.ahnu.edu.cn; Hu, Gangsan

    2013-06-15

    A frustrated Heisenberg model on a stacked square lattice in a striped antiferromagnetic spin order is studied by the Green's function approach. Besides the intra- and inter-layer exchange couplings, the single-ion anisotropy (J{sub s}) is also considered. The expressions of the spin spectrum gap (Δ), the transition temperature (T{sub N}) and the zero-temperature average spin (〈S{sup z}〉{sub 0}) are derived analytically. Their dependences on the single-ion anisotropy are investigated. We find they are all increasing functions of J{sub s}. We make a further estimation of the magnitude of J{sub s} according to the experimental temperature T{sub N}=138K of the pure compound LaFeAsO.

  4. Effect of VO2+ ions on the EPR and optical absorption investigations of lithium sulphate monohydrate single crystals for non linear optical applications

    Science.gov (United States)

    Juliet sheela, K.; Radha Krishnan, S.; Shanmugam, V. M.; Subramanian, P.

    2017-09-01

    Electron paramagnetic resonance (EPR) and optical absorption studies of VO2+ ions in Lithium Sulphate Monohydrate (LSMH) single crystal are carried out at room temperature. Single crystal rotations in each of the three mutually orthogonal crystalline planes, ac, ab, cb indicate three different vanadyl complexes. Three VO2+ ions of EPR spectra indicate among them, that two of them have (the intense two) entered the lattice substitutionally and the third one occupies the interstitial position. From the angular variation, the spin Hamiltonian parameters are evaluated. From the optical absorption spectrum containing four selected bands and EPR data, various bonding parameters are determined and the nature of bonding in the crystal is discussed. Also Second Harmonic Generation (SHG) studies are carried out to confirm the Non Linear Optical (NLO) properties of the given material.

  5. Simplification of physics-based electrochemical model for lithium ion battery on electric vehicle. Part I: Diffusion simplification and single particle model

    Science.gov (United States)

    Han, Xuebing; Ouyang, Minggao; Lu, Languang; Li, Jianqiu

    2015-03-01

    Now the lithium ion batteries are widely used in electrical vehicles (EV). The battery modeling and state estimation is of great significance. The rigorous physic based electrochemical model is too complicated for on-line simulation in vehicle. In this work, the simplification of physics-based model lithium ion battery for application in battery management system (BMS) on real electrical vehicle is proposed. Approximate method for solving the solid phase diffusion and electrolyte concentration distribution problems is introduced. The approximate result is very close to the rigorous model but fewer computations are needed. An extended single particle model is founded based on these approximated results and the on-line state of charge (SOC) estimation algorithm using the extended Kalman filter with this single particle model is discussed. This SOC estimation algorithm could be used in the BMS in real vehicle.

  6. Frequency measurement of the 2S(1/2)-2D(3/2) electric quadrupole transition in a single 171Yb+ ion.

    Science.gov (United States)

    Webster, Stephen; Godun, Rachel; King, Steven; Huang, Guilong; Walton, Barney; Tsatourian, Veronika; Margolis, Helen; Lea, Stephen; Gill, Patrick

    2010-03-01

    We report on precision laser spectroscopy of the 2S(1/2)(F = 0)-2D(3/2) (F = 2, m(F) = 0) clock transition in a single ion of 171Yb+. The absolute value of the transition frequency, determined using an optical frequency comb referenced to a hydrogen maser, is 688358979309310 +/- 9 Hz. This corresponds to a fractional frequency uncertainty of 1.3 x 10(-14).

  7. Analysis of "total toxaphene" and selected single congeners in biota by ion trap HRGC-EI-MS/MS using congener-optimized parent ion dissociations.

    Science.gov (United States)

    Skopp, Sonja; Oehme, Michael; Chu, Fong Lam; Yeboah, Faustinus; Chan, Hing Man

    2002-06-15

    A method for the quantification of selected toxaphene congeners as well as "total toxaphene" was developed based on electron ionization (EI) tandem (MS/MS) ion trap mass spectrometry (MS) and a combination of fragment ion dissociations. Congeners were separated by high-resolution gas chromatography. Compared to conventional EI low-resolution MS, a 5-20-fold gain in sensitivity could be obtained for octa- or nonachlorinated compounds such as toxaphene #26 and #62 (according to Parlar nomenclature), allowing for their detection in the low picogram range in biota. In addition, response factors for important congeners such as #26, #32, #40/41, #42, #44, #50, and #62 deviated not more than a factor of 2, which is much less as compared to negative ion chemical ionization. This reduces the risk for systematic errors when determining total toxaphene on the basis of a limited number of reference compounds or the technical mixture. Furthermore, chlordanes and polychlorinated biphenyls did not interfere when applying the proposed MS/MS technique. The applicability of the method was tested by determining both total toxaphene and levels of selected congeners in six Arctic wildlife samples collected from Nunavut, Canada, as well as by repetitive analyses of the SRM 1588 certified reference material.

  8. Radiation damage induced in Al{sub 2}O{sub 3} single crystal sequentially irradiated with reactor neutrons and 90 MeV Xe ions

    Energy Technology Data Exchange (ETDEWEB)

    Zirour, H. [Faculty of Physics, USTHB, BP. 32, El-Alia, Bab-Ezzouar, Algiers (Algeria); Izerrouken, M., E-mail: izerrouken@yahoo.com [Centre de Recherche Nucléaire de Draria, BP. 43, Sebbala, Draria, Algiers (Algeria); Sari, A. [Centre de Recherche Nucléaire de Berine, BP. 108, Ain-Oussara, Djelfa (Algeria)

    2016-06-15

    The present investigation reports the effect of 90 MeV Xe ion irradiation on neutron irradiated Al{sub 2}O{sub 3} single crystals. Three irradiation experiments were performed, with neutrons only, 90 MeV Xe ions only and with neutrons followed by 90 MeV Xe ions. Neutron and 90 MeV Xe ion irradiations were performed at NUR research reactor, Algiers, Algeria and at GANIL accelerator, Caen, France respectively. After irradiation, the radiation damage was investigated by Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), optical absorption measurements, and X-ray diffraction (XRD) techniques. Raman technique revealed that the concentration of the defects formed in Al{sub 2}O{sub 3} samples subsequently irradiated with neutrons and 90 MeV Xe ions is lower than that formed in Al{sub 2}O{sub 3} samples which were irradiated only with neutrons. This reveals the occurrence of ionization-induced recovery of the neutron damage. Furthermore, as revealed by XRD analysis, a new peak is appeared at about 2θ = 38.03° after irradiation at high fluence (>3 × 10{sup 13} Xe/cm{sup 2}). It can be assigned to the formation of new lattice plane.

  9. Test Standard Revision Update: JESD57, "Procedures for the Measurement of Single-Event Effects in Semiconductor Devices from Heavy-Ion Irradiation"

    Science.gov (United States)

    Lauenstein, Jean-Marie

    2015-01-01

    The JEDEC JESD57 test standard, Procedures for the Measurement of Single-Event Effects in Semiconductor Devices from Heavy-Ion Irradiation, is undergoing its first revision since 1996. In this talk, we place this test standard into context with other relevant radiation test standards to show its importance for single-event effect radiation testing for space applications. We show the range of industry, government, and end-user party involvement in the revision. Finally, we highlight some of the key changes being made and discuss the trade-space in which setting standards must be made to be both useful and broadly adopted.

  10. Analysis of Single-Event Effects in a Radiation-Hardened Low-Jitter PLL Under Heavy Ion and Pulsed Laser Irradiation

    Science.gov (United States)

    Chen, Zhuojun; Lin, Min; Ding, Ding; Zheng, Yunlong; Sang, Zehua; Zou, Shichang

    2017-01-01

    A radiation-hardened low-jitter phase-locked loop (PLL) with a low-mismatch charge pump and a robust voltage-controlled oscillator is designed in a 130 nm PD-SOI process. In order to evaluate the overall response to single-event effects, the accumulated phase jitter has been put forward, which can exclude the inherent noise floor and accumulate all the radiation-induced noise. Then the single-event sensitivity of the proposed PLL is comprehensively analyzed by heavy ion and pulsed laser tests.

  11. Cycle flux algebra for ion and water flux through the KcsA channel single-file pore links microscopic trajectories and macroscopic observables.

    Science.gov (United States)

    Oiki, Shigetoshi; Iwamoto, Masayuki; Sumikama, Takashi

    2011-01-31

    In narrow pore ion channels, ions and water molecules diffuse in a single-file manner and cannot pass each other. Under such constraints, ion and water fluxes are coupled, leading to experimentally observable phenomena such as the streaming potential. Analysis of this coupled flux would provide unprecedented insights into the mechanism of permeation. In this study, ion and water permeation through the KcsA potassium channel was the focus, for which an eight-state discrete-state Markov model has been proposed based on the crystal structure, exhibiting four ion-binding sites. Random transitions on the model lead to the generation of the net flux. Here we introduced the concept of cycle flux to derive exact solutions of experimental observables from the permeation model. There are multiple cyclic paths on the model, and random transitions complete the cycles. The rate of cycle completion is called the cycle flux. The net flux is generated by a combination of cyclic paths with their own cycle flux. T.L. Hill developed a graphical method of exact solutions for the cycle flux. This method was extended to calculate one-way cycle fluxes of the KcsA channel. By assigning the stoichiometric numbers for ion and water transfer to each cycle, we established a method to calculate the water-ion coupling ratio (CR(w-i)) through cycle flux algebra. These calculations predicted that CR(w-i) would increase at low potassium concentrations. One envisions an intuitive picture of permeation as random transitions among cyclic paths, and the relative contributions of the cycle fluxes afford experimental observables.

  12. Reentrant behaviors in the phase diagram of spin-1 planar ferromagnets with easy-axis single-ion anisotropy via the Devlin two-time Green function framework

    Science.gov (United States)

    Mercaldo, M. T.; Rabuffo, I.; De Cesare, L.; Caramico D'Auria, A.

    2017-10-01

    The Devlin two-time Green function framework is used to investigate the role played by the easy-axis single-ion anisotropy on the phase diagram of (d > 2) -dimensional spin-1 planar ferromagnets which exhibit a magnetic-field-induced quantum phase transition (QPT). In this scheme, the exchange anisotropy terms in the equations of motion are treated at the Tyablikov decoupling level while the crystal field anisotropy contribution is handled exactly. The emerging key result is a reentrant structure of the phase diagram close to the quantum critical point for a well defined window of values of the single-ion anisotropy parameter. This experimentally interesting feature was recently recovered by employing the Anderson-Callen decoupling (ACD) which is considered to provide meaningful results only for small values of the single-ion anisotropy parameter. In this context, our findings suggest that the simplest ACD treatment offers the possibility to have, at least qualitatively, a correct physical scenario of quantum criticality close to a field-induced QPT avoiding the limiting mathematical difficulties involved in the Devlin scheme.

  13. Effects of the single-ion anisotropy on magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1, 3/2) cylindrical Ising nanowire

    Science.gov (United States)

    Wang, Wei; Bi, Jiang-lin; Liu, Rui-jia; Chen, Xu; Liu, Jin-ping

    2016-10-01

    Monte Carlo simulation has been performed in detail to study magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1, 3/2) cylindrical Ising nanowire with core-shell structure. The ground phase diagrams are obtained for different single-ion anisotropies. The system can display rich phase transitions such as the second- and first-order phase transitions, the tricritical points and the compensation points. Especially, emphasis has been given to the effects of the single-ion anisotropy and the temperate on the magnetization, the internal energy, the specific heat, the compensation points and hysteresis loops of the system as well as two sublattices. A number of characteristic phenomena such as such as various types of magnetization curves and triple, duadruple as well as quintuple hysteresis loops behaviors have been observed for certain physical parameters, originating from the competitions among the anisotropies, temperature and the longitudinal magnetic field. It is found that the single-ion anisotropy and the temperature strongly affect the coercivity and the remanence of the system. A satisfactory agreement can be achieved from comparisons between our results and previous theoretical and experimental works.

  14. Effects of the random single-ion anisotropy and random magnetic field in the spin-3/2 Blume-Capel model

    Science.gov (United States)

    da Silva, W. P.; de Arruda, P. H. Z.; Tunes, T. M.; Godoy, M.; de Arruda, A. S.

    2017-01-01

    We have studied the effects of the random single-ion anisotropy and random magnetic field in the phase diagram and in the thermodynamic properties of the spin-3/2 Blume-Capel model via Curie-Weiss mean-field approximation. The phase diagrams were built in the planes temperature versus single-ion anisotropy, temperature versus magnetic field, temperature versus random parameters and the dependencies of magnetization were plotted versus temperature and single-ion anisotropy. These diagrams show that, in the space (D / J - T / J) , the type (first- or second-order) of the phase transition between the ferromagnetic and paramagnetic phases is dependent on the random parameters. Therefore, within these conditions the model presents tricritical behavior. For large values, and a certain critical value of the random parameters, the phase transition is only of second-order, but it is of first-order within the ordered phase, between the phase with m = 1 / 2 and m = 3 / 2 , which ends in a terminal critical point.

  15. H{sup −} ion implantation induced ten-fold increase of photoluminescence efficiency in single layer InAs/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Sreekumar, R.; Mandal, A. [Centre for Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra (India); Chakrabarti, S., E-mail: subho@ee.iitb.ac.in [Centre for Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra (India); Gupta, S.K. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India)

    2014-09-15

    We demonstrate a ten-fold increase in photoluminescence (PL) efficiency from 50 keV H{sup −} ion-implanted InAs/GaAs quantum dots (QDs) at a temperature of 8 K and/or 145 K. Enhancement occurred without post-annealing treatment. PL efficiency increased with increasing implantation fluence from 6×10{sup 12} ions/cm{sup 2} up to an optimum value of 2.4×10{sup 13} ions/cm{sup 2}, beyond which PL efficiency decreased drastically (up to a fluence of 2.4×10{sup 15} ions/cm{sup 2}). Passivation of non-radiative recombination centres (due to direct interaction of H{sup −} ions with lattice defects) and de-excitation of photo-generated carriers to QDs through quantum mechanical tunnelling via H{sup −} ion-induced defects (e-traps) that are created near the QD–cap layer interface, resulted in PL efficiency enhancement. Shallow e-traps with activation energy ∼90 meV and 30 meV created near the conduction band of GaAs cap layer for the samples implanted with H{sup −} of fluence 6×10{sup 12} and 2.4×10{sup 13} ions/cm{sup 2} respectively are identified using low temperature PL study. Contribution of de-trapped electrons from the e-traps to the QDs enhanced the PL efficiency at 145 K. Cross-section transmission electron microscopy and X-ray diffraction study revealed that the structural damage created by H{sup −} ions at the high fluence level of 2.4×10{sup 15} ions/cm{sup 2}, caused the degradation in PL efficiency. - Highlights: • Self-assembled single layer InAs/GaAs quantum dots. • Low energy hydrogen ion implantation. • PL efficiency enhancement for implanted samples. • Eradication of defects from dots and capping layers.

  16. Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiao-Guang; Kerr, John B.

    2004-07-11

    Network single ion conductors (NSICs) based on comb-branch polyepoxide ethers and lithium bis(allylmalonato) borate have been synthesized and thoroughly characterized by means of ionic conductivity measurements, electrochemical impedance and by dynamic mechanical analysis (DMA). The materials have been tested as battery electrolytes by cycling in symmetrical Li/Li half cells and in Li/V{sub 6}O{sub 13} full cells in which the NSIC was used as both binder and electrolyte in the cathode electrode and as the electrolyte separator membrane,. The substitution of the trimethylene oxide (TMO) unit into the side chains in place of ethylene oxide (EO) units increased the polymerion mobility (lower glass transition temperature). However, the ionic conductivity was nearly one and half orders of magnitude lower than the corresponding pure EO based single ion conductor at the same salt concentration. This effect may be ascribed to the lower dielectric constant of the TMO side chains that result in a lower concentration of free conducting lithium cations. For a highly cross-linked system (EO/Li=20), only 47 wt% plasticizing solvent (ethylene carbonate (EC)/ethyl methyl carbonate (EMC), 1/1 by wt) could be taken up and the ionic conductivity was only increased by one order of magnitude over the dry polyelectrolyte while for a less densely crosslinked system (EO/Li=80), up to 75 wt% plasticizer could be taken up and the ionic conductivity was increased by nearly two orders of magnitude. A Li/Li symmetric cell that was cycled at 85 C at a current density of 25{micro}Acm{sup -2} showed no concentration polarization or diffusional relaxation, consistent with a lithium ion transference number of one. However, both the bulk and interfacial impedances increased after 20 cycles, apparently due to continued cross-linking reactions within the membrane and on the surface of the lithium electrodes. A Li/V{sub 6}O{sub 13} full cell constructed using a single ion conductor gel (propylene

  17. Lanthanide ion and tetrathiafulvalene-based ligand as a "magic" couple toward luminescence, single molecule magnets, and magnetostructural correlations.

    Science.gov (United States)

    Pointillart, Fabrice; le Guennic, Boris; Cador, Olivier; Maury, Olivier; Ouahab, Lahcène

    2015-11-17

    The synthesis of molecules featuring different properties is a perpetual challenge for the chemists' community. The coexistence and even more the synergy of those properties open new perspectives in the field of molecular devices and molecular electronics. In that sense, coordination chemistry contributed to the development of new functional molecules through, for instance, single-molecule magnets (SMMs) and light emitting molecules with potential applications in high capacity data storage and OLEDs, respectively. The appealing combination of both electronic properties into one single object may offer the possibility to have magnetized luminescent entities at nanometric scale. To that end, lanthanides seem to be one of the key ingredients since their peculiar electronic structures endow them with specific magnetic and luminescence properties. Indeed, lanthanides cover a wide range of emission wavelengths, from infrared to UV, which add up to a large variety of magnetic behaviors, from the fully isotropic spin (e.g., Gd(III)) to highly anisotropic magnetic moments (e.g., Dy(III)). In lanthanide complexes, ligands play a fundamental role because on one hand they govern the orientation of the magnetic moment of anisotropic lanthanides and on the other hand they can sensitize efficiently the luminescence. The design of appropriate organic ligands to elaborate such chemical objects with the desired property appears to be essential but remains a perpetual challenge. In this Account, we describe the design of lanthanide-based complexes that emit light, behave as SMMs, or combine both properties. We have paid peculiar attention to the design of ligands based on the tetrathiafulvalene (TTF) moiety. TTF and its derivatives are well-known chemical entities, stable at different oxidation states, and employed mainly in the synthesis of molecular conductors and superconductors. In addition to their redox properties, TTF-based derivatives act as organic chromophores for the

  18. Stability of hybrid modes of a single-component electron plasma containing an admixture of background gas ions

    Science.gov (United States)

    Yeliseyev, Yu. N.

    2014-05-01

    The spectrum of eigenmodes of a waveguide completely filled with a cold electron plasma containing a small admixture of ions produced due to electron-impact ionization of background gas atoms is calculated numerically. The calculations were performed within the entire range of allowable values of the radial electric and longitudinal magnetic fields for both magnetized and unmagnetized ions by using the earlier derived nonlocal dispersion relation [Plasma Phys. Rep. 36, 563 (2010)]. The spectrum consists of three families of electron modes with frequencies equal to the Doppler-shifted upper and lower hybrid frequencies and modified ion cyclotron (MIC) modes. When the Doppler shift caused by electron rotation in the crossed electric and magnetic fields compensates for the hybrid frequency, the electron modes become low-frequency modes and interact with the ion modes. For m = 1, only the lower hybrid modes can be low-frequency ones, whereas at m ≥ 2, both lower and upper hybrid modes can be low-frequency ones. The spectrum of modes having the azimuthal number m = 2 is thoroughly analyzed. It is shown that, in this case, the lower hybrid modes behave similar to the m = 1 modes. The dispersion curves of the upper hybrid modes intersect with all harmonics of the MIC frequency (positive, negative, and zero) and are unstable in the vicinities of the intersections. The maximum value of the instability growth rate is several times higher than the ion plasma frequency. The MIC modes are unstable within a wide range of the field strengths, and their growth rates are two orders of magnitude slower. Instabilities are caused by the relative motion of electrons and ions (the transverse current) and the anisotropy of the ion distribution function.

  19. Effects of monovalent and divalent salts on the phospholipid and fatty acid compositions of a halotolerant Planococcus sp.

    Science.gov (United States)

    Miller, K J

    1986-09-01

    The phospholipid headgroup and fatty acid compositions of a halotolerant Planococcus sp. (strain A4a) were examined when cells were grown in the presence of high concentrations of a variety of salts. The fatty acid composition of Planococcus sp. strain A4a was altered primarily as a function of the osmolality of the growth medium. The phospholipid headgroup composition was influenced by both the osmolality of the growth medium and the nature of the cation species present. An increase in the cardiolipin/phosphatidylglycerol molar ratio was detected when cells were grown in the presence of high concentrations of monovalent cations.

  20. Single-molecule elasticity of single-stranded DNA, a model flexible polyelectrolyte

    Science.gov (United States)

    McIntosh, Dustin B.

    Understanding the structure of unfolded, flexible polyelectrolytes is important for our comprehension of basic processes in molecular biology (e.g., RNA and protein folding) and our ability to exploit the polymers in technology (e.g., in self-assembled nanostructures). Here, we investigate the structure of single single-stranded DNA molecules and their interactions with ions using magnetic tweezers. Our data reveal that single-stranded DNA is not well-described by ideal polymer models such as the Worm-Like Chain. At low force, we report the first experimental observation of a nonlinear elastic regime revealing the relevance of long-range excluded volume effects. At high force, the extension scales as a logarithm in monovalent salt. Molecular dynamics simulations indicate that this logarithmic regime is the result of ion-stabilized wrinkles at short-length scales along the polymer backbone. Addition of divalent salt to the buffer results in enhanced elasticity indicating increased wrinkling or polymer ''wrapping" around the divalent ions. Using a thermodynamic identity, we are able to count ions as they are released into the bulk upon polymer elongation. We find that ssDNA releases significantly more ions than dsDNA. We posit that the recently termed ''Snake-Like Chain" model (Ullner, J. Phys. Chem B (2003)) for flexible polyelectrolytes may explain these observations. As a first step towards characterizing biologically relevant nucleic acid structures, we measure the effects of base-stacking on ssDNA elasticity. We find that base-stacking in poly(dA) significantly enhances the rigidity of the polymer as evidenced by the low-force elasticity. The unstacking transition of poly(dA) at high force reveals that the intrinsic electrostatic tension on the molecule varies significantly more weakly on salt concentration than predictions from mean-field models. Further, we provide a model-independent estimate of the free energy difference between stacked and unstacked nucleic