WorldWideScience

Sample records for co2 cluster ion

  1. CO2 laser photolysis of clustered ions, (1)

    International Nuclear Information System (INIS)

    Ikezoe, Yasumasa; Soga, Takeshi; Suzuki, Kazuya; Ohno, Shin-ichi.

    1990-09-01

    Vibrational excitation and the following decomposition of cluster ions by CO 2 laser photons are studied. Characteristics of the cluster ion and the CO 2 laser photon are summarized in their relation to the photolysis of cluster ions. An apparatus was installed, which is composed of (1) corona discharge-jet expansion section (formation of cluster ions), (2) CO 2 laser section (photolysis of cluster ions), and (3) mass spectrometer section. Experimental results of ammonia cluster ions were described. Effects of repeller voltage, shape of repellers, and adiabatic cooling are examined on the formation of ammonia cluster ions by corona discharge-jet expansion method. Collisional dissociation of cluster ions was observed at high repeller voltages. Size distribution of the ammonia cluster ion is discussed in connection with the temperature of cluster ions. Intensity of CO 2 laser was related to decomposition yield of cluster ions. (author)

  2. CO2 laser photo-induced decomposition of ammoniated ammonium ions

    International Nuclear Information System (INIS)

    Ikezoe, Yasumasa; Soga, Takesi; Suzuki, Kazuya; Moriyama, Noboru; Ohno, Shin-ichi

    1995-01-01

    Photo-induced decomposition of ammoniated (clustered) ammonium ions was studied using a CO 2 laser to excite vibrational levels of the cluster ion. A tandem mass spectrometer (TMS) was installed with two quadrupole mass filters, a corona discharge ionization chamber, and a series of einzel lenses. Cluster ions of NH 4 + ·nNH 3 with n=1-7 were formed in TMS, and found to decompose at the frequency of 1077 cm -1 to an extent in proportional to laser intensity. CO 2 laser between 925 and 1055 do not decompose the cluster ions with laser intensities examined. (author)

  3. Indium tin oxide surface smoothing by gas cluster ion beam

    CERN Document Server

    Song, J H; Choi, W K

    2002-01-01

    CO sub 2 cluster ions are irradiated at the acceleration voltage of 25 kV to remove hillocks on indium tin oxide (ITO) surfaces and thus to attain highly smooth surfaces. CO sub 2 monomer ions are also bombarded on the ITO surfaces at the same acceleration voltage to compare sputtering phenomena. From the atomic force microscope results, the irradiation of monomer ions makes the hillocks sharper and the surfaces rougher from 1.31 to 1.6 nm in roughness. On the other hand, the irradiation of CO sub 2 cluster ions reduces the height of hillocks and planarize the ITO surfaces as smooth as 0.92 nm in roughness. This discrepancy could be explained by large lateral sputtering yield of the cluster ions and re-deposition of sputtered particles by the impact of the cluster ions on surfaces.

  4. IR photodissociation spectroscopy of (OCS){sub n}{sup +} and (OCS){sub n}{sup −} cluster ions: Similarity and dissimilarity in the structure of CO{sub 2}, OCS, and CS{sub 2} cluster ions

    Energy Technology Data Exchange (ETDEWEB)

    Inokuchi, Yoshiya, E-mail: y-inokuchi@hiroshima-u.ac.jp; Ebata, Takayuki [Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

    2015-06-07

    Infrared photodissociation (IRPD) spectra of (OCS){sub n}{sup +} and (OCS){sub n}{sup −} (n = 2–6) cluster ions are measured in the 1000–2300 cm{sup −1} region; these clusters show strong CO stretching vibrations in this region. For (OCS){sub 2}{sup +} and (OCS){sub 2}{sup −}, we utilize the messenger technique by attaching an Ar atom to measure their IR spectra. The IRPD spectrum of (OCS){sub 2}{sup +}Ar shows two bands at 2095 and 2120 cm{sup −1}. On the basis of quantum chemical calculations, these bands are assigned to a C{sub 2} isomer of (OCS){sub 2}{sup +}, in which an intermolecular semi-covalent bond is formed between the sulfur ends of the two OCS components by the charge resonance interaction, and the positive charge is delocalized over the dimer. The (OCS){sub n}{sup +} (n = 3–6) cluster ions show a few bands assignable to “solvent” OCS molecules in the 2000–2080 cm{sup −1} region, in addition to the bands due to the (OCS){sub 2}{sup +} ion core at ∼2090 and ∼2120 cm{sup −1}, suggesting that the dimer ion core is kept in (OCS){sub 3–6}{sup +}. For the (OCS){sub n}{sup −} cluster anions, the IRPD spectra indicate the coexistence of a few isomers with an OCS{sup −} or (OCS){sub 2}{sup −} anion core over the cluster range of n = 2–6. The (OCS){sub 2}{sup −}Ar anion displays two strong bands at 1674 and 1994 cm{sup −1}. These bands can be assigned to a C{sub s} isomer with an OCS{sup −} anion core. For the n = 2–4 anions, this OCS{sup −} anion core form is dominant. In addition to the bands of the OCS{sup −} core isomer, we found another band at ∼1740 cm{sup −1}, which can be assigned to isomers having an (OCS){sub 2}{sup −} ion core; this dimer core has C{sub 2} symmetry and {sup 2}A electronic state. The IRPD spectra of the n = 3–6 anions show two IR bands at ∼1660 and ∼2020 cm{sup −1}. The intensity of the latter component relative to that of the former one becomes stronger and stronger with

  5. Comprehensive cluster-theory analysis of the magnetic structures and excitations in CoCl2·2H2O

    DEFF Research Database (Denmark)

    Jensen, Jens; Larsen, Jacob; Hansen, Ursula B.

    2018-01-01

    The magnetic properties of CoCl2·2H2O are analyzed in the mean-field/random-phase approximation using a basis of clusters with four spins along the c-axis chains of Co ions. The model gives a unifying account of the bulk properties, the spin waves, and the higher-order cluster-spin excitations...... at a transverse field of 160 kOe and is found to agree closely with their observations....

  6. Carbon nanotube growth from catalytic nano-clusters formed by hot-ion-implantation into the SiO{sub 2}/Si interface

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Yasushi, E-mail: yhoshino@kanagawa-u.ac.jp [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Arima, Hiroki; Yokoyama, Ai; Saito, Yasunao; Nakata, Jyoji [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan)

    2012-07-01

    We have studied growth of chirality-controlled carbon nanotubes (CNTs) from hot-implantation-formed catalytic nano-clusters in a thermally grown SiO{sub 2}/Si substrate. This procedure has the advantage of high controllability of the diameter and the number of clusters by optimizing the conditions of the ion implantation. In the present study, Co{sup +} ions with ion dose of 8 Multiplication-Sign 10{sup 16} cm{sup -2} are implanted in the vicinity of the SiO{sub 2}/Si interface at 300 Degree-Sign C temperature. The implanted Co atoms located in the SiO{sub 2} layer has an amorphous-like structure with a cluster diameter of several nm. In contrast, implanted Co atoms in the Si substrate are found to take a cobalt silicide structure, confirmed by the high-resolution image of transmission electron microscope. CNTs are grown by microwave-plasma-enhanced chemical vapor deposition. We have confirmed a large amount of vertically-aligned multi-walled CNTs from the Co nano-clusters formed by the hot-ion-implantation near the SiO{sub 2}/Si interface.

  7. Irradiation characteristics of metal-cluster-complex ions containing diverse multi-elements with large mass differences

    International Nuclear Information System (INIS)

    Fujiwara, Yukio; Kondou, Kouji; Teranishi, Yoshikazu; Nonaka, Hidehiko; Saito, Naoaki; Fujimoto, Toshiyuki; Kurokawa, Akira; Ichimura, Shingo; Tomita, Mitsuhiro

    2007-01-01

    Tetrairidium dodecacarbonyl, Ir 4 (CO) 12 , is a metal cluster complex which has a molecular weight of 1104.9. Using a metal-cluster-complex ion source, the interaction between Ir 4 (CO) n + ions (n=0-12) and silicon substrates was studied at a beam energy ranging from 2keV to 10keV at normal incidence. By adjusting Wien-filter voltage, the influence of CO ligands was investigated. Experimental results showed that sputtering yield of silicon bombarded with Ir 4 (CO) n + ions at 10keV decreased with the number of CO ligands. In the case of 2keV, deposition tended to be suppressed by removing CO ligands from the impinging cluster ions. The influence of CO ligands was explained by considering changes in surface properties caused by the irradiation of Ir 4 (CO) n + ions. It was also found that the bombardment with Ir 4 (CO) 7 + ions at 2.5keV caused deposition on silicon target

  8. Dependence of energy per molecule on sputtering yields with reactive gas cluster ions

    International Nuclear Information System (INIS)

    Toyoda, Noriaki; Yamada, Isao

    2010-01-01

    Gas cluster ions show dense energy deposition on a target surface, which result in the enhancement of chemical reactions. In reactive sputtering with gas cluster ions, the energy per atom or molecule plays an important role. In this study, the average cluster size (N, the number of atoms or molecules in a cluster ion) was controlled; thereby the dependences of the energy per molecule on the sputtering yields of carbon by CO 2 cluster ions and that of Si by SF 6 /Ar mixed gas cluster ions were investigated. Large CO 2 cluster ions with energy per molecule of 1 eV showed high reactive sputtering yield of an amorphous carbon film. However, these ions did not cause the formation of large craters on a graphite surface. It is possible to achieve very low damage etching by controlling the energy per molecule of reactive cluster ions. Further, in the case of SF 6 /Ar mixed cluster ions, it was found that reactive sputtering was enhanced when a small amount of SF 6 gas (∼10%) was mixed with Ar. The reactive sputtering yield of Si by one SF 6 molecule linearly increased with the energy per molecule.

  9. Experimental Ion Mobility measurements in Ne-CO$_2$ and CO$_2$-N$_2$ mixtures

    CERN Document Server

    Encarnação, P.M.C.C.; Veenhof, R.; Neves, P.N.B.; Santos, F.P.; Trindade, A.M.F.; Borges, F.I.G.M.; Conde, C.A.N.

    2016-01-01

    In this paper we present the experimental results for the mobility, K0, of ions in neon-carbon dioxide (Ne-CO2) and carbon dioxide-nitrogen (CO2-N2) gaseous mixtures for total pressures ranging from 8–12 Torr, reduced electric fields in the 10–25 Td range, at room temperature. Regarding the Ne-CO2 mixture only one peak was observed for CO2 concentrations above 25%, which has been identified as an ion originated in CO2, while below 25% of CO2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 ± 0.05 and 1.07 ± 0.01 cm2V−1s−1 in the 10%-99% interval of CO2, and from 4.61 ± 0.19 to 3.00 ± 0.09 cm2V−1s−1 for the second peak observed (10%–25% of CO2). For the CO2-N2, the time-of-arrival spectra displayed only one peak for CO2 concentrations above 10%, which was attributed to ions originated in CO2, namely CO2+(CO2), with a second peak appearing for CO2 concentrations below 10%. This secon...

  10. Dependence of surface smoothing, sputtering and etching phenomena on cluster ion dosage

    CERN Document Server

    Song, J H; Choi, W K

    2002-01-01

    The dependence of surface smoothing and sputtering phenomena of Si (1 0 0) solid surfaces irradiated by CO sub 2 cluster ions on cluster-ion dosage was investigated using an atomic force microscope. The flux and total ion dosage of impinging cluster ions at the acceleration voltage of 50 kV were fixed at 10 sup 9 ions/cm sup 2 s and were scanned from 5x10 sup 1 sup 0 to 5x10 sup 1 sup 3 ions/cm sup 2 , respectively. The density of hillocks induced by cluster ion impact was gradually increased with the dosage up to 5x10 sup 1 sup 1 ions/cm sup 2 , which caused that the irradiated surface became rough from 0.4 to 1.24 nm in root-mean-square roughness (sigma sub r sub m sub s). At the boundary of the ion dosage of 10 sup 1 sup 2 ions/cm sup 2 , the density of the induced hillocks was decreased and sigma sub r sub m sub s was about 1.21 nm, not being deteriorated further. At the dosage of 5x10 sup 1 sup 3 ions/cm sup 2 , the induced hillocks completely disappeared and the surface became very flat as much as sigma...

  11. Observations of different core water cluster ions Y-(H2O)n (Y = O2, HOx, NOx, COx) and magic number in atmospheric pressure negative corona discharge mass spectrometry.

    Science.gov (United States)

    Sekimoto, Kanako; Takayama, Mitsuo

    2011-01-01

    Reliable mass spectrometry data from large water clusters Y(-)(H(2)O)(n) with various negative core ions Y(-) such as O(2)(-), HO(-), HO(2)(-), NO(2)(-), NO(3)(-), NO(3)(-)(HNO(3))(2), CO(3)(-) and HCO(4)(-) have been obtained using atmospheric pressure negative corona discharge mass spectrometry. All the core Y(-) ions observed were ionic species that play a central role in tropospheric ion chemistry. These mass spectra exhibited discontinuities in ion peak intensity at certain size clusters Y(-)(H(2)O)(m) indicating specific thermochemical stability. Thus, Y(-)(H(2)O)(m) may correspond to the magic number or first hydrated shell in the cluster series Y(-)(H(2)O)(n). The high intensity discontinuity at HO(-)(H(2)O)(3) observed was the first mass spectrometric evidence for the specific stability of HO(-)(H(2)O)(3) as the first hydrated shell which Eigen postulated in 1964. The negative ion water clusters Y(-)(H(2)O)(n) observed in the mass spectra are most likely to be formed via core ion formation in the ambient discharge area (760 torr) and the growth of water clusters by adiabatic expansion in the vacuum region of the mass spectrometers (≈1 torr). The detailed mechanism of the formation of the different core water cluster ions Y(-)(H(2)O)(n) is described. Copyright © 2010 John Wiley & Sons, Ltd.

  12. Co2+ ion exchange with NaY

    International Nuclear Information System (INIS)

    Garcia, I.; Solache-Rios, M.; Bulbulian, S.; Bosch, P.

    1993-01-01

    Co 2+ ion exchange from aqueous cobalt chloride-sodium chloride solutions with NaY zeolite has been investigated. The effect of contact time on the sorption of Co 2+ by dehydrated Y zeolite at 150 degrees C is unusual. A fast sorption uptake is observed in which 1.73 mequiv/g of zeolite of Na + ions is replaced by cobalt ions, followed by a desorption process where the uptake decreases to 1.56 mequiv/g of zeolite. This behavior is explained by the location and coordination of cobalt in Y zeolite sites. It is suggested that the maximum uptake corresponds to cobalt ions being simultaneously in two sites; tetrahedrally coordinated in the sodalite units and octahedrally coordinated in the large cavities. It is also suggested that the desorption process is a consequence of a reaction between Cl - ions and the tetrahedral species. 20 refs., 4 figs

  13. On the mechanism of water cluster-ion formation in carbon dioxide

    International Nuclear Information System (INIS)

    Warneck, P.; Rakshit, A.B.

    1981-01-01

    A drift chamber mass spectrometer has been used to study the formation of water cluster-ions in carbon dioxide containing traces of water vapour. The dominant reaction sequences were identified up to the fourth generation of daughter ions starting with CO 2 + . The subsequent reaction mechanism remains uncertain and several possibilities are discussed. The final ions are H 3 O + H 2 O and H 3 O + (H 2 O) 2 . The significance of the reaction schemes to the radiation chemistry of carbon dioxide is pointed out. (orig.)

  14. Photodissociation of Cr(CO) within methanol clusters: Observation of an isotope effect

    International Nuclear Information System (INIS)

    Peifer, W.R.; Garvey, J.F.

    1991-01-01

    Mixed van der Waals clusters containing Cr(CO) 6 and methanol are generated in the free-jet expansion of a pulsed beam of seeded helium and subjected to 248-nm multiphoton ionization (MPI), and the product ions are analyzed by time-of-flight mass spectrometry. The authors find that the multiphoton dissociation and ionization dynamics of solvated Cr(CO) 6 are strikingly different from those of the naked molecule. Two principle sequences of heterocluster ions are identified in the mass spectrum: a minor sequence with the empirical formula, S n Cr(CO) x + (x = 5,6), where S is a methanol molecule, and a major sequence with the empirical formula, S n Cr(CO) x + (x = 0,1,2). Implications are discussed regarding the general utility of MPI as a probe of the electronic structure and reactivity within van der Waals clusters

  15. Cluster ion beam facilities

    International Nuclear Information System (INIS)

    Popok, V.N.; Prasalovich, S.V.; Odzhaev, V.B.; Campbell, E.E.B.

    2001-01-01

    A brief state-of-the-art review in the field of cluster-surface interactions is presented. Ionised cluster beams could become a powerful and versatile tool for the modification and processing of surfaces as an alternative to ion implantation and ion assisted deposition. The main effects of cluster-surface collisions and possible applications of cluster ion beams are discussed. The outlooks of the Cluster Implantation and Deposition Apparatus (CIDA) being developed in Guteborg University are shown

  16. Fragmentation of cluster ions produced by electron impact ionization

    International Nuclear Information System (INIS)

    Parajuli, R.

    2001-12-01

    By studying fragmentation of dimer and cluster ions produced by electron impact ionization of a neutral cluster beam, it is possible to elucidate structure, stability and energetics of these species and the dynamics of the corresponding decay reactions. Fragmentation of carbon cluster ions formed from C 6 0 fullerenes, rare gas cluster ions and dimer ions and simple molecular cluster ions (oxygen and nitrogen) and dimer ions have been studied in this thesis using a high resolution two sector field mass spectrometer of reversed geometry and a NIER type electron impact ion source. Spontaneous decay reactions of triply and quadruply charged C 4 0 z + and C 4 1 z + cluster ions which are formed from C 6 0 fullerenes by electron impact ionization have been analyzed. A new but very weak decay reaction for the even-sized carbon clusters ions is observed, namely loss of C 3 . The odd-sized clusters ions preferentially decay by loss of carbon atoms and, to a lesser degree, trimers. A weak signal due to C 2 loss is observed for C 4 1 3 + ion. These decay channels are discussed in terms of the geometric structure of these metastable, relatively cold cluster ions. Measurements on metastable fragmentation of mass selected rare gas cluster ions (Ne, Ar, Kr) which are produced by electron impact ionization of a neutral rare gas cluster beam have been carried out. From the shape of the fragment ion peaks (MIKE scan technique) information about the distribution of kinetic energy that is released in the decay reaction can be deduced. In this study, the peak shape observed for cluster ions with sizes larger than five is Gaussian and thus from the peak width the mean kinetic energy release of the corresponding decay reactions can be calculated. Using finite heat bath theory, the binding energies of the decaying cluster ions are calculated from these data and have been compared to data in the literature where available. In addition to the decay reactions of cluster ions the metastable

  17. Properties of an ionised-cluster beam from a vaporised-cluster ion source

    International Nuclear Information System (INIS)

    Takagi, T.; Yamada, I.; Sasaki, A.

    1978-01-01

    A new type of ion source vaporised-metal cluster ion source, has been developed for deposition and epitaxy. A cluster consisting of 10 2 to 10 3 atoms coupled loosely together is formed by adiabatic expansion ejecting the vapour of materials into a high-vacuum region through the nozzle of a heated crucible. The clusters are ionised by electron bombardment and accelerated with neutral clusters toward a substrate. In this paper, mechanisms of cluster formation experimental results of the cluster size (atoms/cluster) and its distribution, and characteristics of the cluster ion beams are reported. The size is calculated from the kinetic equation E = (1/2)mNVsub(ej) 2 , where E is the cluster beam energy, Vsub(ej) is the ejection velocity, m is the mass of atom and N is the cluster size. The energy and the velocity of the cluster are measured by an electrostatic 127 0 energy analyser and a rotating disc system, respectively. The cluster size obtained for Ag is about 5 x 10 2 to 2 x 10 3 atoms. The retarding potential method is used to confirm the results for Ag. The same dependence on cluster size for metals such as Ag, Cu and Pb has been obtained in previous experiments. In the cluster state the cluster ion beam is easily produced by electron bombardment. About 50% of ionised clusters are obtained under typical operation conditions, because of the large ionisation cross sections of the clusters. To obtain a uniform spatial distribution, the ionising electrode system is also discussed. The new techniques are termed ionised-cluster beam deposition (ICBD) and epitaxy (ICBE). (author)

  18. A quadrupole ion trap as low-energy cluster ion beam source

    CERN Document Server

    Uchida, N; Kanayama, T

    2003-01-01

    Kinetic energy distribution of ion beams was measured by a retarding field energy analyzer for a mass-selective cluster ion beam deposition system that uses a quadrupole ion trap as a cluster ion beam source. The results indicated that the system delivers a cluster-ion beam with energy distribution of approx 2 eV, which corresponded well to the calculation results of the trapping potentials in the ion trap. Using this deposition system, mass-selected hydrogenated Si cluster ions Si sub n H sub x sup + were actually deposited on Si(111)-(7x7) surfaces at impact kinetic energy E sub d of 3-30 eV. Observation by using a scanning tunneling microscope (STM) demonstrated that Si sub 6 H sub x sup + cluster ions landed on the surface without decomposition at E sub d =3 eV, while the deposition was destructive at E sub d>=18 eV. (author)

  19. Communication: CO oxidation by silver and gold cluster cations: Identification of different active oxygen species

    International Nuclear Information System (INIS)

    Popolan, Denisia M.; Bernhardt, Thorsten M.

    2011-01-01

    The oxidation of carbon monoxide with nitrous oxide on mass-selected Au 3 + and Ag 3 + clusters has been investigated under multicollision conditions in an octopole ion trap experiment. The comparative study reveals that for both gold and silver cations carbon dioxide is formed on the clusters. However, whereas in the case of Au 3 + the cluster itself acts as reactive species that facilitates the formation of CO 2 from N 2 O and CO, for silver the oxidized clusters Ag 3 O x + (n= 1-3) are identified as active in the CO oxidation reaction. Thus, in the case of the silver cluster cations N 2 O is dissociated and one oxygen atom is suggested to directly react with CO, whereas a second kind of oxygen strongly bound to silver is acting as a substrate for the reaction.

  20. Communication: CO oxidation by silver and gold cluster cations: Identification of different active oxygen species

    Science.gov (United States)

    Popolan, Denisia M.; Bernhardt, Thorsten M.

    2011-03-01

    The oxidation of carbon monoxide with nitrous oxide on mass-selected Au3+ and Ag3+ clusters has been investigated under multicollision conditions in an octopole ion trap experiment. The comparative study reveals that for both gold and silver cations carbon dioxide is formed on the clusters. However, whereas in the case of Au3+ the cluster itself acts as reactive species that facilitates the formation of CO2 from N2O and CO, for silver the oxidized clusters Ag3Ox+ (n = 1-3) are identified as active in the CO oxidation reaction. Thus, in the case of the silver cluster cations N2O is dissociated and one oxygen atom is suggested to directly react with CO, whereas a second kind of oxygen strongly bound to silver is acting as a substrate for the reaction.

  1. Chemistry and kinetics of size-selected cobalt cluster cations at thermal energies. I. Reactions with CO

    Science.gov (United States)

    Guo, B. C.; Kerns, K. P.; Castleman, A. W., Jr.

    1992-06-01

    The chemistry and kinetics of size-selected Co+n cluster-ion (n=2-8) reactions with CO are studied using a selected ion drift tube affixed with a laser vaporization source operated under well-defined thermal conditions. All reactions studied in the present work are found to be association reactions. Their absolute rate constants, which are determined quantitatively, are found to have a strong dependence on cluster size. Similar to the cases of reactions with many other reactants such as H2 and CH4, Co+4 and Co+5 display a higher reactivity toward the CO molecule than do clusters of neighboring size. The multiple-collision conditions employed in the present work have enabled a determination of the maximum coordination number of CO molecules bound onto each Co+n cluster. It is found that the tetramer tends to bond 12 CO molecules, the pentamer 14 CO, hexamer 16 CO, and so on. The results are interpreted in terms of Lauher's calculation and the polyhedral skeletal electron pair theory. All the measured maximum coordination numbers correlate extremely well with the predictions of these theories, except for the trimer where the measured number is one CO less than the predicted value. The good agreement between experiment and theory enables one to gain some insight into the geometric structure of the clusters. Based on the present findings, the cobalt tetramer cation is interpreted to have a tetrahedral structure, the pentamer a trigonal bipyramid, and the hexamer an octahedral structure. Other cluster structures are also discussed.

  2. Experimental ion mobility measurements in Xe-CO2

    Science.gov (United States)

    Cortez, A. F. V.; Santos, M. A. G.; Veenhof, R.; Patra, R. N.; Neves, P. N. B.; Santos, F. P.; Borges, F. I. G. M.; Conde, C. A. N.

    2017-06-01

    Data on ion mobility is important to improve the performance of large volume gaseous detectors. In the present work the method, experimental setup and results for the ion mobility measurements in Xe-CO2 mixtures are presented. The results for this mixture show the presence of only one peak for all gas ratios of Xe-CO2, low reduced electric fields, E/N, 10-25 Td (2.4-6.1 kV·cm-1·bar-1), low pressures 6-8 Torr (8-10.6 mbar), at room temperature.

  3. A Cluster of CO2 Change Characteristics with GOSAT Observations for Viewing the Spatial Pattern of CO2 Emission and Absorption

    Directory of Open Access Journals (Sweden)

    Da Liu

    2015-11-01

    Full Text Available Satellite observations can be used to detect the changes of CO2 concentration at global and regional scales. With the column-averaged CO2 dry-air mole fraction (Xco2 data derived from satellite observations, the issue is how to extract and assess these changes, which are related to anthropogenic emissions and biosphere absorptions. We propose a k-means cluster analysis to extract the temporally changing features of Xco2 in the Central-Eastern Asia using the data from 2009 to 2013 obtained by Greenhouse Gases Observing Satellite (GOSAT, and assess the effects of anthropogenic emissions and biosphere absorptions on CO2 changes combining with the data of emission and vegetation net primary production (NPP. As a result, 14 clusters, which are 14 types of Xco2 seasonal changing patterns, are obtained in the study area by using the optimal clustering parameters. These clusters are generally in agreement with the spatial pattern of underlying anthropogenic emissions and vegetation absorptions. According to correlation analysis with emission and NPP, these 14 clusters are divided into three groups: strong emission, strong absorption, and a tendency of balancing between emission and absorption. The proposed clustering approach in this study provides us with a potential way to better understand how the seasonal changes of CO2 concentration depend on underlying anthropogenic emissions and vegetation absorptions.

  4. Mass Spectrum Analysis of CO2 and N2 Using Ion Beam Separator System

    International Nuclear Information System (INIS)

    Tjipto-Sujitno, BA; Darsono; Agus-Santoso

    2000-01-01

    The main purpose of this research is to study investigate the massspectrum profile of CO 2 and N 2 emitted from Penning ion source using ionbeam separator. Besides that, it is also identified the compositions of CO 2 and N 2 ion gas and their abundances through their mass spectrum profile,because as we know that these ions are consist of ion of atom or molecule aswell as the their abundances. To get these profiles, the ion beam acceleratedin accelerating tube are passed through magnet separator. After passing themagnet separator, the ion current beam was detected using microampere meter.By scanning the strength of magnetic field, it will be found the currentspectrum profile as a function of magnetic field. From this current spectrum,we can make a mass spectrum profile. From experiment done, it was found thatthe mass spectrum peak of CO 2 and N 2 were C + with m/z = (12.00 ± 0.10)amu, O 2 + = (31.96 ± 0.29) amu, CO 2 + = (43.93 ± 0.31) amu, N + (13.97 ± 0.33) amu, and N 2 + = (28.05 ± 0.18) amu. (author)

  5. Infrared Spectroscopy of Gas-Phase M+(CO2)n (M = Co, Rh, Ir) Ion-Molecule Complexes.

    Science.gov (United States)

    Iskra, Andreas; Gentleman, Alexander S; Kartouzian, Aras; Kent, Michael J; Sharp, Alastair P; Mackenzie, Stuart R

    2017-01-12

    The structures of gas-phase M + (CO 2 ) n (M = Co, Rh, Ir; n = 2-15) ion-molecule complexes have been investigated using a combination of infrared resonance-enhanced photodissociation (IR-REPD) spectroscopy and density functional theory. The results provide insight into fundamental metal ion-CO 2 interactions, highlighting the trends with increasing ligand number and with different group 9 ions. Spectra have been recorded in the region of the CO 2 asymmetric stretch around 2350 cm -1 using the inert messenger technique and their interpretation has been aided by comparison with simulated infrared spectra of calculated low-energy isomeric structures. All vibrational bands in the smaller complexes are blue-shifted relative to the asymmetric stretch in free CO 2 , consistent with direct binding to the metal center dominated by charge-quadrupole interactions. For all three metal ions, a core [M + (CO 2 ) 2 ] structure is identified to which subsequent ligands are less strongly bound. No evidence is observed in this size regime for complete activation or insertion reactions.

  6. Low-energy irradiation effects of gas cluster ion beams

    International Nuclear Information System (INIS)

    Houzumi, Shingo; Takeshima, Keigo; Mochiji, Kozo; Toyoda, Noriaki; Yamada, Isao

    2007-01-01

    A cluster-ion irradiation system with cluster-size selection has been developed to study the effects of the cluster size for surface processes using cluster ions. A permanent magnet with a magnetic field of 1.2 T is installed for size separation of large cluster ions. Trace formations at HOPG surface by the irradiation with size-selected Ar-cluster ions under acceleration energy of 30 keV were investigated by a scanning tunneling microscopy. Generation behavior of the crater-like traces is strongly affected by the number of constituent atoms (cluster size) of the irradiating cluster ion. When the incident cluster ion is composed of 100-3000 atoms, crater-like traces are observed on the irradiated surfaces. In contrast, such traces are not observed at all with the irradiation of the cluster-ions composed of over 5000 atoms. Such the behavior is discussed on the basis of the kinetic energy per constituent atom of the cluster ion. To study GCIB irradiation effects against macromolecule, GCIB was irradiated on DNA molecules absorbed on graphite surface. By the GCIB irradiation, much more DNA molecules was sputtered away as compared with the monomer-ion irradiation. (author)

  7. Detection of gold cluster ions by ion-to-ion conversion using a CsI-converter

    International Nuclear Information System (INIS)

    Nguyen, V.-T.; Novilkov, A.C.; Obnorskii, V.V.

    1997-01-01

    Gold cluster ions in the m/z range of 10 4 -2 x 10 6 u were produced by bombarding a thin film of gold with 252 Cf-fission fragments. The gold covering a C-Al substrate formed islets having a mean diameter of 44 A. Their size- and mass-distribution was determined by means of electron microscopy. The main task was to measure the m/z distribution of the cluster ions ejected from the sample surface. For this purpose we built a time-of-flight (TOF) mass spectrometer, which could be used as a linear TOF instrument or, alternatively, as a tandem-TOF instrument being equipped with an ion-to-ion converter. Combining the results obtained in both modes, it turned out that the linear TOF instrument equipped with micro-channel plates had a mean detection efficiency for 20 keV cluster ions of about 40%. In the tandem mode, the cluster ions hit a CsI converter with energies of 40z keV (z = charge state), from where secondary ions - mainly Cs + and (CsI) n Cs + cluster ions - were ejected. These ions were used to measure the TOF spectrum of the gold cluster ions. The detection efficiency of the cluster ions was found to vary in the available mass range from 99.7% to 96.5%. The complete mass distribution between 4 x 10 4 and 4 x 10 6 u was determined and compared with the corresponding mass distribution of the gold islets covering the substrate. (orig.)

  8. Ultrathin mesoporous Co_3O_4 nanosheets-constructed hierarchical clusters as high rate capability and long life anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wu, Shengming; Xia, Tian; Wang, Jingping; Lu, Feifei; Xu, Chunbo; Zhang, Xianfa; Huo, Lihua; Zhao, Hui

    2017-01-01

    Graphical abstract: Ultrathin mesoporous Co_3O_4 nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment. When tested as anode materials for LIBs, UMCN-HCs achieve high reversible capacity, good long cycling life, and rate capability. - Highlights: • UMCN-HCs show high capacity, excellent stability, and good rate capability. • UMCN-HCs retain a capacity of 1067 mAh g"−"1 after 100 cycles at 100 mA g"−"1. • UMCN-HCs deliver a capacity of 507 mAh g"−"1 after 500 cycles at 2 A g"−"1. - Abstract: Herein, Ultrathin mesoporous Co_3O_4 nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment at 600 °C in air. The products consist of cluster-like Co_3O_4 microarchitectures, which are assembled by numerous ultrathin mesoporous Co_3O_4 nanosheets. When tested as anode materials for lithium-ion batteries, UMCN-HCs deliver a high reversible capacity of 1067 mAh g"−"1 at a current density of 100 mA g"−"1 after 100 cycles. Even at 2 A g"−"1, a stable capacity as high as 507 mAh g"−"1 can be achieved after 500 cycles. The high reversible capacity, excellent cycling stability, and good rate capability of UMCN-HCs may be attributed to their mesoporous sheet-like nanostructure. The sheet-layered structure of UMCN-HCs may buffer the volume change during the lithiation-delithiation process, and the mesoporous characteristic make lithium-ion transfer more easily at the interface between the active electrode and the electrolyte.

  9. Effect of charge state and stoichiometry on the structure and reactivity of nickel oxide clusters with CO

    Science.gov (United States)

    Johnson, Grant E.; Reilly, Nelly M.; Castleman, A. W., Jr.

    2009-02-01

    The collision induced fragmentation and reactivity of cationic and anionic nickel oxide clusters with carbon monoxide were studied experimentally using guided-ion-beam mass spectrometry. Anionic clusters with a stoichiometry containing one more oxygen atom than nickel atom (NiO2-, Ni2O3-, Ni3O4- and Ni4O5-) were found to exhibit dominant products resulting from the transfer of a single oxygen atom to CO, suggesting the formation of CO2. Of these four species, Ni2O3- and Ni4O5- were observed to be the most reactive having oxygen transfer products accounting for approximately 5% and 10% of the total ion intensity at a maximum pressure of 15 mTorr of CO. Our findings, therefore, indicate that anionic nickel oxide clusters containing an even number of nickel atoms and an odd number of oxygen atoms are more reactive than those with an odd number of nickel atoms and an even number of oxygen atoms. The majority of cationic nickel oxides, in contrast to anionic species, reacted preferentially through the adsorption of CO onto the cluster accompanied by the loss of either molecular O2 or nickel oxide units. The adsorption of CO onto positively charged nickel oxides, therefore, is exothermic enough to break apart the gas-phase clusters. Collision induced dissociation experiments, employing inert xenon gas, were also conducted to gain insight into the structural properties of nickel oxide clusters. The fragmentation products were found to vary considerably with size and stoichiometry as well as ionic charge state. In general, cationic clusters favored the collisional loss of molecular O2 while anionic clusters fragmented through the loss of both atomic oxygen and nickel oxide units. Our results provide insight into the effect of ionic charge state on the structure of nickel oxide clusters. Furthermore, we establish how the size and stoichiometry of nickel oxide clusters influences their ability to oxidize CO, an important reaction for environmental pollution abatement.

  10. Mixed clusters from the coexpansion of C2F6 and n2 in a pulsed, supersonic expansion cluster ion source and beam deflection time-of-flight mass spectrometer: A first application

    Science.gov (United States)

    Thompson, Steven D.

    The following topics are discussed: (1) cluster ion genesis; (2) cluster ion detection; (3) Ion source; (4) pulse valve; (5) e-gun; (6) Ion optics; (7) a first order model; and (8) a modified Bakker's model.

  11. Doping effects of Co2+ ions on ZnO nanorods and their photocatalytic properties

    International Nuclear Information System (INIS)

    Qiu Xiaoqing; Li Guangshe; Sun Xuefei; Li Liping; Fu Xianzhi

    2008-01-01

    A series of Zn 1-x Co x O nanorods with dopant content ranging from x = 0.00 to 0.10 was prepared by a wet chemical method. All Zn 1-x Co x O samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersion x-ray line mapping analysis, and UV-visible absorption spectroscopy. It was found that Co 2+ ions were homogeneously substituted for Zn 2+ ions in ZnO nanorods. Rhodamine B degradation was used as a probe reaction to evaluate the effect of Co 2+ doping on ZnO nanorods and photocatalytic performance under UV light and visible light irradiation. Co 2+ ions acted as the trapping or recombination centers for electrons and holes, leading to a reduction in photodegradation efficiency under UV light illumination. Alternatively, Co 2+ ions enhanced the optical absorption and produced the photoinduced carriers under visible illumination in terms of two charge transfer transitions involving Co 2+ ions. Consequently, Co 2+ ions substituted in the lattice of ZnO nanorods significantly improved the visible light photocatalytic activity

  12. Gold cluster carbonyls: saturated adsorption of CO on gold cluster cations, vibrational spectroscopy, and implications for their structures.

    Science.gov (United States)

    Fielicke, André; von Helden, Gert; Meijer, Gerard; Pedersen, David B; Simard, Benoit; Rayner, David M

    2005-06-15

    We report on the interaction of carbon monoxide with cationic gold clusters in the gas phase. Successive adsorption of CO molecules on the Au(n)(+) clusters proceeds until a cluster size specific saturation coverage is reached. Structural information for the bare gold clusters is obtained by comparing the saturation stoichiometry with the number of available equivalent sites presented by candidate structures of Au(n)(+). Our findings are in agreement with the planar structures of the Au(n)(+) cluster cations with n < or = 7 that are suggested by ion mobility experiments [Gilb, S.; Weis, P.; Furche, F.; Ahlrichs, R.; Kappes, M. M. J. Chem. Phys. 2001, 116, 4094]. By inference we also establish the structure of the saturated Au(n)(CO)(m)(+) complexes. In certain cases we find evidence suggesting that successive adsorption of CO can distort the metal cluster framework. In addition, the vibrational spectra of the Au(n)(CO)(m)(+) complexes in both the CO stretching region and in the region of the Au-C stretch and the Au-C-O bend are measured using infrared photodepletion spectroscopy. The spectra further aid in the structure determination of Au(n)(+), provide information on the structure of the Au(n)(+)-CO complexes, and can be compared with spectra of CO adsorbates on deposited clusters or surfaces.

  13. Cluster Ions and Atmospheric Processes

    Science.gov (United States)

    D'Auria, R.; Turco, R. P.

    clusters in the middle and lower atmosphere and their role in aerosol formation; a thesis topic proposal, unpublished ms., June 14, 2001. D'Auria, R. and R. P. Turco, Ionic clusters in the polar winter stratosphere, Geophys. Res. Lett., 28, 3871-3874, 2001. Eisele, F. L., First tandem mass spectrometric measurements of tropospheric ions, J. Geophys. Res., 93, 716-724, 1988. Hamill, P., and R. P. Turco, Ion nucleation of NAT in ternary system polar stratospheric clouds, Trans. Amer. Geophys. Union, 81 (19, May 9, 2000) Suppl., S97, 2000. 1 Keesee, R. G. and A. W. Castleman, Jr., The chemical kinetic of aerosol formation, The strato- spheric aerosol layer, edited by R. C. Whitten, pp. 69-92, Springer-Verlag, New York, 1982. Tanner, D. J., and F. L. Eisele, Ions in oceanic and continental air mass, J. Geophis. Res., 96, 1023-1031, 1991. Thomson, J. J., Conduction of electricity through gases, Cambridge University Press, Cam- bridge, 1906. Viggiano, A. A. and F. Arnold, The first height measurements of the negative ion composition of the stratosphere, Planet Space sci., 29, 895, 1981. 2

  14. Structurally simple supported platinum clusters prepared from [Pt15(CO)30]2- on magnesium oxide

    NARCIS (Netherlands)

    Chang, J.R.; Koningsberger, D.C.; Gates, B.C.

    1992-01-01

    A G. Longoni-P. Chini (1976) cluster, [Pt15(CO)30]2-, was prepd. on MgO powder by a surface-mediated synthesis from Na2PtCl6 in the presence of CO. The formation of [Pt15(CO)30]2- and its decarbonylation at 120 Deg under vacuum were characterized by IR and x-ray spectra. The decarbonylated cluster

  15. Ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets-constructed hierarchical clusters as high rate capability and long life anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shengming [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Xia, Tian, E-mail: xiatian@hlju.edu.cn [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Wang, Jingping [Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Heilongjiang, Harbin 150001 (China); Lu, Feifei [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Xu, Chunbo [Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Heilongjiang, Harbin 150001 (China); Zhang, Xianfa; Huo, Lihua [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China); Zhao, Hui, E-mail: zhaohui98@yahoo.com [Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education, School of Chemistry, Chemical Engineering and Materials, Heilongjiang University, Heilongjiang, Harbin 150080 (China)

    2017-06-01

    Graphical abstract: Ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment. When tested as anode materials for LIBs, UMCN-HCs achieve high reversible capacity, good long cycling life, and rate capability. - Highlights: • UMCN-HCs show high capacity, excellent stability, and good rate capability. • UMCN-HCs retain a capacity of 1067 mAh g{sup −1} after 100 cycles at 100 mA g{sup −1}. • UMCN-HCs deliver a capacity of 507 mAh g{sup −1} after 500 cycles at 2 A g{sup −1}. - Abstract: Herein, Ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets-constructed hierarchical clusters (UMCN-HCs) have been successfully synthesized via a facile hydrothermal method followed by a subsequent thermolysis treatment at 600 °C in air. The products consist of cluster-like Co{sub 3}O{sub 4} microarchitectures, which are assembled by numerous ultrathin mesoporous Co{sub 3}O{sub 4} nanosheets. When tested as anode materials for lithium-ion batteries, UMCN-HCs deliver a high reversible capacity of 1067 mAh g{sup −1} at a current density of 100 mA g{sup −1} after 100 cycles. Even at 2 A g{sup −1}, a stable capacity as high as 507 mAh g{sup −1} can be achieved after 500 cycles. The high reversible capacity, excellent cycling stability, and good rate capability of UMCN-HCs may be attributed to their mesoporous sheet-like nanostructure. The sheet-layered structure of UMCN-HCs may buffer the volume change during the lithiation-delithiation process, and the mesoporous characteristic make lithium-ion transfer more easily at the interface between the active electrode and the electrolyte.

  16. ALMA Detects CO(3-2) within a Super Star Cluster in NGC 5253

    Science.gov (United States)

    Turner, Jean L.; Consiglio, S. Michelle; Beck, Sara C.; Goss, W. M.; Ho, Paul. T. P.; Meier, David S.; Silich, Sergiy; Zhao, Jun-Hui

    2017-09-01

    We present observations of CO(3-2) and 13CO(3-2) emission near the supernebula in the dwarf galaxy NGC 5253, which contains one of the best examples of a potential globular cluster in formation. The 0.″3 resolution images reveal an unusual molecular cloud, “Cloud D1,” that is coincident with the radio-infrared supernebula. The ˜6 pc diameter cloud has a linewidth, Δ v = 21.7 {km} {{{s}}}-1, that reflects only the gravitational potential of the star cluster residing within it. The corresponding virial mass is 2.5 × 105 {M}⊙ . The cluster appears to have a top-heavy initial mass function, with M * ≳ 1-2 {M}⊙ . Cloud D1 is optically thin in CO(3-2), probably because the gas is hot. Molecular gas mass is very uncertain but constitutes <35% of the dynamical mass within the cloud boundaries. In spite of the presence of an estimated ˜1500-2000 O stars within the small cloud, the CO appears relatively undisturbed. We propose that Cloud D1 consists of molecular clumps or cores, possibly star-forming, orbiting with more evolved stars in the core of the giant cluster.

  17. Incorporation of μ3-CO3 into an MnIII/MnIV Mn12 cluster: {[(cyclam)MnIV(μ-O)2MnIII(H2O)(μ-OH)]6(μ3-CO3)2}Cl8·24H2O

    Science.gov (United States)

    Levaton, Ben B.; Olmstead, Marilyn M.

    2010-01-01

    The centrosymmetric title cluster, hexa­aquadi-μ3-carbonato-hexa­cyclamhexa-μ2-hydroxido-dodeca-μ2-oxido-hexa­mang­an­ese(IV)hexa­manganese(III) octa­chloride tetra­cosa­hydrate, [Mn12(CO3)2O12(OH)6(C10H24N4)6(H2O)6]Cl8·24H2O, has two μ3-CO3 groups that not only bridge octahedrally coordinated MnIII ions but also act as acceptors to two different kinds of hydrogen bonds. The carbonate anion is planar within experimental error and has an average C—O distance of 1.294 (4) Å. The crystal packing is stabilized by O—H⋯Cl, O—H⋯O, N—H⋯Cl and N—H⋯O hydrogen bonds. Two of the four independent chloride ions are disordered over five positions, and eight of the 12 independent water mol­ecules are disordered over 21 positions. PMID:21587382

  18. Control of cluster ion sizes for efficient injection heating

    International Nuclear Information System (INIS)

    Enjoji, Hiroshi; Be, S.H.; Yano, Katsuki; Okamoto, Kosuke

    1976-01-01

    For heating of plasmas by injection of hydrogen cluster ions, the specific size (N/Z) approximately 10 2 molecules/charge is believed to be most desirable. A fundamental research to develop a practical method for tailoring large cluster ions into small suitable sizes has been carried out by using nitrogen cluster ions of the initial mean specific size (N/Z) 0 approximately 10 5 . The beam of neutral large clusters of total intensity 20 mAsub(eq) was led to an ionizer and then the large cluster ions are accelerated to 8.9 keV before entering the divider which disintegrates them into small fragments by multiple ionization. The mean specific size of disintegrated cluster ions (N/Z)' becomes smaller with increase in ionizing electron current of the divider. (N/Z)' becomes 10 3 approximately 10 4 at an electron current of 140 mA and an accelerating voltage of 680 V of the divider with its efficiency of 20 approximately 60%. Thus, the original large cluster ions are divided into small fragments of which the mean specific size is 1/20 approximately 1/100 of the initial value without much decrease in total intensity of the cluster ion beam

  19. Irradiation effects of Ar cluster ion beams on Si substrates

    International Nuclear Information System (INIS)

    Ishii, Masahiro; Sugahara, Gaku; Takaoka, G.H.; Yamada, Isao

    1993-01-01

    Gas-cluster ion beams can be applied to new surface modification techniques such as surface cleaning, low damage sputtering and shallow junction formation. The effects of energetic Ar cluster impacts on solid surface were studied for cluster energies of 10-30keV. Irradiation effects were studied by RBS. For Si(111) substrates, irradiated with Ar ≥500 clusters to a dose of 1x10 15 ion/cm 2 at acceleration voltage 15kV, 2x10 14 atoms/cm 2 implanted Ar atoms were detected. In this case, the energy per cluster atom was smaller than 30eV; at this energy, no significant implantation occurs in the case of monomer ions. Ar cluster implantation into Si substrates occurred due to the high energy density irradiation. (author)

  20. Influence of residual Ar+ in Ar cluster ion beam for DLC film formation

    International Nuclear Information System (INIS)

    Kitagawa, Teruyuki; Miyauchi, Kazuya; Toyoda, Noriaki; Kanda, Kazuhiro; Ikeda, Tokumi; Tsubakino, Harushige; Matsuo, Jiro; Matsui, Shinji; Yamada, Isao

    2003-01-01

    In order to study the influences of residual Ar monomer ion (Ar + ) on sp 2 content and hardness of diamond like carbon (DLC) films formed by Ar cluster ion beam assisted deposition, Ar cluster ion, Ar + and their mixed ions (Ar cluster ion and Ar + ) bombardments were performed during evaporation of C 60 . From near edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopy measurements, lower sp 2 content in the carbon films was obtained with Ar cluster ion bombardment than that with Ar + and mixed ion. Furthermore higher hardness and smooth surface were shown with Ar cluster ion bombardments. Therefore it was important to reduce Ar + in Ar cluster ion beams to obtain hard DLC films with flat surface

  1. Lithium formate ion clusters formation during electrospray ionization: Evidence of magic number clusters by mass spectrometry and ab initio calculations

    International Nuclear Information System (INIS)

    Shukla, Anil; Bogdanov, Bogdan

    2015-01-01

    Small cationic and anionic clusters of lithium formate were generated by electrospray ionization and their fragmentations were studied by tandem mass spectrometry (collision-induced dissociation with N 2 ). Singly as well as multiply charged clusters were formed in both positive and negative ion modes with the general formulae, (HCOOLi) n Li + , (HCOOLi) n Li m m+ , (HCOOLi) n HCOO − , and (HCOOLi) n (HCOO) m m− . Several magic number cluster (MNC) ions were observed in both the positive and negative ion modes although more predominant in the positive ion mode with (HCOOLi) 3 Li + being the most abundant and stable cluster ion. Fragmentations of singly charged positive clusters proceed first by the loss of a dimer unit ((HCOOLi) 2 ) followed by the loss of monomer units (HCOOLi) although the former remains the dominant dissociation process. In the case of positive cluster ions, all fragmentations lead to the magic cluster (HCOOLi) 3 Li + as the most abundant fragment ion at higher collision energies which then fragments further to dimer and monomer ions at lower abundances. In the negative ion mode, however, singly charged clusters dissociated via sequential loss of monomer units. Multiply charged clusters in both positive and negative ion modes dissociated mainly via Coulomb repulsion. Quantum chemical calculations performed for smaller cluster ions showed that the trimer ion has a closed ring structure similar to the phenalenylium structure with three closed rings connected to the central lithium ion. Further additions of monomer units result in similar symmetric structures for hexamer and nonamer cluster ions. Thermochemical calculations show that trimer cluster ion is relatively more stable than neighboring cluster ions, supporting the experimental observation of a magic number cluster with enhanced stability

  2. Raman spectroscopy of few-layer graphene prepared by C2–C6 cluster ion implantation

    International Nuclear Information System (INIS)

    Wang, Z.S.; Zhang, R.; Zhang, Z.D.; Huang, Z.H.; Liu, C.S.; Fu, D.J.; Liu, J.R.

    2013-01-01

    Few-layer graphene has been prepared on 300 nm-thick Ni films by C 2 –C 6 cluster ion implantation at 20 keV/cluster. Raman spectroscopy reveals significant influence of the number of atoms in the cluster, the implantation dose, and thermal treatment on the structure of the graphene layers. In particular, the graphene samples exhibit a sharp G peak at 1584 cm −1 and 2D peaks at 2711–2717 cm −1 . The I G /I 2D ratios higher than 1.70 and I G /I D ratio as high as 1.95 confirm that graphene sheets with low density of defects have been synthesized with much improved quality by ion implantation with larger clusters of C 4 –C 6

  3. Comparison of secondary ion emission yields for poly-tyrosine between cluster and heavy ion impacts

    International Nuclear Information System (INIS)

    Hirata, K.; Saitoh, Y.; Chiba, A.; Yamada, K.; Takahashi, Y.; Narumi, K.

    2010-01-01

    Emission yields of secondary ions necessary for the identification of poly-tyrosine were compared for incident ion impacts of energetic cluster ions (0.8 MeV C 8 + , 2.4 MeV C 8 + , and 4.0 MeV C 8 + ) and swift heavy monoatomic molybdenum ions (4.0 MeV Mo + and 14 MeV Mo 4+ ) with similar mass to that of the cluster by time-of-flight secondary ion mass analysis combined with secondary ion electric current measurements. The comparison revealed that (1) secondary ion emission yields per C 8 + impact increase with increasing incident energy within the energy range examined, (2) the 4.0 MeV C 8 + impact provides higher emission yields than the impact of the monoatomic Mo ion with the same incident energy (4.0 MeV Mo + ), and (3) the 2.4 MeV C 8 + impact exhibits comparable emission yields to that for the Mo ion impact with higher incident energy (14 MeV Mo 4+ ). Energetic cluster ion impacts effectively produce the characteristic secondary ions for poly-tyrosine, which is advantageous for highly sensitive amino acid detection in proteins using time-of-flight secondary ion mass analysis.

  4. Minimization of Ion-Solvent Clusters in Gel Electrolytes Containing Graphene Oxide Quantum Dots for Lithium-Ion Batteries.

    Science.gov (United States)

    Chen, Yen-Ming; Hsu, Shih-Ting; Tseng, Yu-Hsien; Yeh, Te-Fu; Hou, Sheng-Shu; Jan, Jeng-Shiung; Lee, Yuh-Lang; Teng, Hsisheng

    2018-03-01

    This study uses graphene oxide quantum dots (GOQDs) to enhance the Li + -ion mobility of a gel polymer electrolyte (GPE) for lithium-ion batteries (LIBs). The GPE comprises a framework of poly(acrylonitrile-co-vinylacetate) blended with poly(methyl methacrylate) and a salt LiPF 6 solvated in carbonate solvents. The GOQDs, which function as acceptors, are small (3-11 nm) and well dispersed in the polymer framework. The GOQDs suppress the formation of ion-solvent clusters and immobilize PF6- anions, affording the GPE a high ionic conductivity and a high Li + -ion transference number (0.77). When assembled into Li|electrolyte|LiFePO 4 batteries, the GPEs containing GOQDs preserve the battery capacity at high rates (up to 20 C) and exhibit 100% capacity retention after 500 charge-discharge cycles. Smaller GOQDs are more effective in GPE performance enhancement because of the higher dispersion of QDs. The minimization of both the ion-solvent clusters and degree of Li + -ion solvation in the GPEs with GOQDs results in even plating and stripping of the Li-metal anode; therefore, Li dendrite formation is suppressed during battery operation. This study demonstrates a strategy of using small GOQDs with tunable properties to effectively modulate ion-solvent coordination in GPEs and thus improve the performance and lifespan of LIBs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Utilizing Co2+/Co3+ Redox Couple in P2-Layered Na0.66Co0.22Mn0.44Ti0.34O2 Cathode for Sodium-Ion Batteries.

    Science.gov (United States)

    Wang, Qin-Chao; Hu, Enyuan; Pan, Yang; Xiao, Na; Hong, Fan; Fu, Zheng-Wen; Wu, Xiao-Jing; Bak, Seong-Min; Yang, Xiao-Qing; Zhou, Yong-Ning

    2017-11-01

    Developing sodium-ion batteries for large-scale energy storage applications is facing big challenges of the lack of high-performance cathode materials. Here, a series of new cathode materials Na 0.66 Co x Mn 0.66- x Ti 0.34 O 2 for sodium-ion batteries are designed and synthesized aiming to reduce transition metal-ion ordering, charge ordering, as well as Na + and vacancy ordering. An interesting structure change of Na 0.66 Co x Mn 0.66- x Ti 0.34 O 2 from orthorhombic to hexagonal is revealed when Co content increases from x = 0 to 0.33. In particular, Na 0.66 Co 0.22 Mn 0.44 Ti 0.34 O 2 with a P2-type layered structure delivers a reversible capacity of 120 mAh g -1 at 0.1 C. When the current density increases to 10 C, a reversible capacity of 63.2 mAh g -1 can still be obtained, indicating a promising rate capability. The low valence Co 2+ substitution results in the formation of average Mn 3.7+ valence state in Na 0.66 Co 0.22 Mn 0.44 Ti 0.34 O 2 , effectively suppressing the Mn 3+ -induced Jahn-Teller distortion, and in turn stabilizing the layered structure. X-ray absorption spectroscopy results suggest that the charge compensation of Na 0.66 Co 0.22 Mn 0.44 Ti 0.34 O 2 during charge/discharge is contributed by Co 2.2+ /Co 3+ and Mn 3.3+ /Mn 4+ redox couples. This is the first time that the highly reversible Co 2+ /Co 3+ redox couple is observed in P2-layered cathodes for sodium-ion batteries. This finding may open new approaches to design advanced intercalation-type cathode materials.

  6. Electron impact ionization of size selected hydrogen clusters (H2)N: ion fragment and neutral size distributions.

    Science.gov (United States)

    Kornilov, Oleg; Toennies, J Peter

    2008-05-21

    Clusters consisting of normal H2 molecules, produced in a free jet expansion, are size selected by diffraction from a transmission nanograting prior to electron impact ionization. For each neutral cluster (H2)(N) (N=2-40), the relative intensities of the ion fragments Hn+ are measured with a mass spectrometer. H3+ is found to be the most abundant fragment up to N=17. With a further increase in N, the abundances of H3+, H5+, H7+, and H9+ first increase and, after passing through a maximum, approach each other. At N=40, they are about the same and more than a factor of 2 and 3 larger than for H11+ and H13+, respectively. For a given neutral cluster size, the intensities of the ion fragments follow a Poisson distribution. The fragmentation probabilities are used to determine the neutral cluster size distribution produced in the expansion at a source temperature of 30.1 K and a source pressure of 1.50 bar. The distribution shows no clear evidence of a magic number N=13 as predicted by theory and found in experiments with pure para-H2 clusters. The ion fragment distributions are also used to extract information on the internal energy distribution of the H3+ ions produced in the reaction H2+ + H2-->H3+ +H, which is initiated upon ionization of the cluster. The internal energy is assumed to be rapidly equilibrated and to determine the number of molecules subsequently evaporated. The internal energy distribution found in this way is in good agreement with data obtained in an earlier independent merged beam scattering experiment.

  7. Properties of clusters in the gas phase: V. Complexes of neutral molecules onto negative ions

    International Nuclear Information System (INIS)

    Keesee, R.G.; Lee, N.; Castleman, A.W. Jr.

    1980-01-01

    Ion--molecules association reactions of the form A - (B)/sub n1/-+B=A - (B)/sub n/ were studied over a range of temperatures in the gas phase using high pressure mass spectrometry. Enthalpy and entropy changes were determined for the stepwise clustering reactions of (1) sulfur dioxide onto Cl - , I - , and NO 2 - with n ranging from one to three or four, and onto SO 2 - and SO 3 - with n equal to one; and (2) carbon dioxide onto Cl - , I - , NO 2 - , CO 3 - , and SO 3 - with n equal to one. From these data and earlier hydration results, the order of the magnitude of the enthalpy changes on the association of the first neutral for a series of negative ions was found to parallel the gas-phase basicity of those anions. For any given ion, the relative order of the addition enthalpies among the neutrals was found to be dependent on the polarizabilities of the neutrals and on the covalency in the ion-neutral bond. Dispersion of charge via covalent bonding was found to affect significantly the succeeding clustering steps

  8. Rapid thermal and swift heavy ion induced annealing of Co ion implanted GaN films

    International Nuclear Information System (INIS)

    Baranwal, V.; Pandey, A. C.; Gerlach, J. W.; Rauschenbach, B.; Karl, H.; Kanjilal, D.; Avasthi, D. K.

    2008-01-01

    Thin epitaxial GaN films grown on 6H-SiC(0001) substrates were implanted with 180 keV Co ions at three different fluences. As-implanted samples were characterized with secondary ion mass spectrometry and Rutherford backscattering spectrometry to obtain the Co depth profiles and the maximum Co concentrations. As-implanted samples were annealed applying two different techniques: rapid thermal annealing and annealing by swift heavy ion irradiation. Rapid thermal annealing was done at two temperatures: 1150 deg. C for 20 s and 700 deg. C for 5 min. 200 MeV Ag ions at two fluences were used for annealing by irradiation. Crystalline structure of the pristine, as-implanted, and annealed samples was investigated using x-ray diffraction, and the results were compared. Improvement of the crystalline quality was observed for rapid thermal annealed samples at the higher annealing temperature as confirmed with rocking curve measurements. The results indicate the presence of Co clusters in these annealed samples. Swift heavy ion irradiation with the parameters chosen for this study did not lead to a significant annealing

  9. Binding energies of cluster ions

    International Nuclear Information System (INIS)

    Parajuli, R.; Matt, S.; Scheier, P.; Echt, O.; Stamatovic, A.; Maerk, T.D.

    2002-01-01

    The binding energy of charged clusters may be measured by analyzing the kinetic energy released in the metastable decay of mass selected parent ions. Using finite heat bath theory to determine the binding energies of argon, neon, krypton, oxygen and nitrogen from their respective average kinetic energy released were carried out. A high-resolution double focussing two-sector mass spectrometer of reversed Nier-Johnson type geometry was used. MIKE ( mass-analysed ion kinetic energy) were measured to investigate decay reactions of mass-selected ions. For the inert gases neon (Ne n + ), argon (Ar n + ) and krypton (Kr n + ), it is found that the binding energies initially decrease with increasing size n and then level off at a value above the enthalpy of vaporization of the condensed phase. Oxygen cluster ions shown a characteristic dependence on cluster size (U-shape) indicating a change in the metastable fragmentation mechanism when going from the dimer to the decamer ion. (nevyjel)

  10. Major signal suppression from metal ion clusters in SFC/ESI-MS - Cause and effects.

    Science.gov (United States)

    Haglind, Alfred; Hedeland, Mikael; Arvidsson, Torbjörn; Pettersson, Curt E

    2018-05-01

    The widening application area of SFC-MS with polar analytes and water-containing samples facilitates the use of quick and simple sample preparation techniques such as "dilute and shoot" and protein precipitation. This has also introduced new polar interfering components such as alkali metal ions naturally abundant in e.g. blood plasma and urine, which have shown to be retained using screening conditions in SFC/ESI-TOF-MS and causing areas of major ion suppression. Analytes co-eluting with these clusters will have a decreased signal intensity, which might have a major effect on both quantification and identification. When investigating the composition of the alkali metal clusters using accurate mass and isotopic pattern, it could be concluded that they were previously not described in the literature. Using NaCl and KCl standards and different chromatographic conditions, varying e.g. column and modifier, the clusters proved to be formed from the alkali metal ions in combination with the alcohol modifier and make-up solvent. Their compositions were [(XOCH 3 ) n  + X] + , [(XOH) n  + X] + , [(X 2 CO 3 ) n  + X] + and [(XOOCOCH 3 ) n  + X] + for X = Na + or K + in ESI+. In ESI-, the clusters depended more on modifier, with [(XCl) n  + Cl] - and [(XOCH 3 ) n  + OCH 3 ] - mainly formed in pure methanol and [(XOOCH) n  + OOCH] - when 20 mM NH 4 Fa was added. To prevent the formation of the clusters by avoiding methanol as modifier might be difficult, as this is a widely used modifier providing good solubility when analyzing polar compounds in SFC. A sample preparation with e.g. LLE would remove the alkali ions, however also introducing a time consuming and discriminating step into the method. Since the alkali metal ions were retained and affected by chromatographic adjustments as e.g. mobile phase modifications, a way to avoid them could therefore be chromatographic tuning, when analyzing samples containing them. Copyright © 2018 Elsevier

  11. Nonlinear damage effect in graphene synthesis by C-cluster ion implantation

    International Nuclear Information System (INIS)

    Zhang Rui; Zhang Zaodi; Wang Zesong; Wang Shixu; Wang Wei; Fu Dejun; Liu Jiarui

    2012-01-01

    We present few-layer graphene synthesis by negative carbon cluster ion implantation with C 1 , C 2 , and C 4 at energies below 20 keV. The small C-clusters were produced by a source of negative ion by cesium sputtering with medium beam current. We show that the nonlinear effect in cluster-induced damage is favorable for graphene precipitation compared with monomer carbon ions. The nonlinear damage effect in cluster ion implantation shows positive impact on disorder reduction, film uniformity, and the surface smoothness in graphene synthesis.

  12. Theoretical study on the spectroscopic properties of CO3(*-).nH2O clusters: extrapolation to bulk.

    Science.gov (United States)

    Pathak, Arup K; Mukherjee, Tulsi; Maity, Dilip K

    2008-10-24

    Vertical detachment energies (VDE) and UV/Vis absorption spectra of hydrated carbonate radical anion clusters, CO(3)(*-).nH(2)O (n=1-8), are determined by means of ab initio electronic structure theory. The VDE values of the hydrated clusters are calculated with second-order Moller-Plesset perturbation (MP2) and coupled cluster theory using the 6-311++G(d,p) set of basis functions. The bulk VDE value of an aqueous carbonate radical anion solution is predicted to be 10.6 eV from the calculated weighted average VDE values of the CO(3)(*-).nH(2)O clusters. UV/Vis absorption spectra of the hydrated clusters are calculated by means of time-dependent density functional theory using the Becke three-parameter nonlocal exchange and the Lee-Yang-Parr nonlocal correlation functional (B3LYP). The simulated UV/Vis spectrum of the CO(3)(*-).8H(2)O cluster is in excellent agreement with the reported experimental spectrum for CO(3)(*-) (aq), obtained based on pulse radiolysis experiments.

  13. Fragmentation pathways of tungsten hexacarbonyl clusters upon electron ionization

    Energy Technology Data Exchange (ETDEWEB)

    Neustetter, M.; Jabbour Al Maalouf, E.; Denifl, S., E-mail: Stephan.Denifl@uibk.ac.at, E-mail: plimaovieira@fct.unl.pt [Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Limão-Vieira, P., E-mail: Stephan.Denifl@uibk.ac.at, E-mail: plimaovieira@fct.unl.pt [Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica (Portugal)

    2016-08-07

    Electron ionization of neat tungsten hexacarbonyl (W(CO){sub 6}) clusters has been investigated in a crossed electron-molecular beam experiment coupled with a mass spectrometer system. The molecule is used for nanofabrication processes through electron beam induced deposition and ion beam induced deposition techniques. Positive ion mass spectra of W(CO){sub 6} clusters formed by electron ionization at 70 eV contain the ion series of the type W(CO){sub n}{sup +} (0 ≤ n ≤ 6) and W{sub 2}(CO){sub n}{sup +} (0 ≤ n ≤ 12). In addition, a series of peaks are observed and have been assigned to WC(CO){sub n}{sup +} (0 ≤ n ≤ 3) and W{sub 2}C(CO){sub n}{sup +} (0 ≤ n ≤ 10). A distinct change of relative fragment ion intensity can be observed for clusters compared to the single molecule. The characteristic fragmentation pattern obtained in the mass spectra can be explained by a sequential decay of the ionized organometallic, which is also supported by the study of the clusters when embedded in helium nanodroplets. In addition, appearance energies for the dissociative ionization channels for singly charged ions have been estimated from experimental ion efficiency curves.

  14. Study of shallow junction formation by boron-containing cluster ion implantation of silicon and two-stage annealing

    Science.gov (United States)

    Lu, Xin-Ming

    Shallow junction formation made by low energy ion implantation and rapid thermal annealing is facing a major challenge for ULSI (ultra large scale integration) as the line width decreases down to the sub micrometer region. The issues include low beam current, the channeling effect in low energy ion implantation and TED (transient enhanced diffusion) during annealing after ion implantation. In this work, boron containing small cluster ions, such as GeB, SiB and SiB2, was generated by using the SNICS (source of negative ion by cesium sputtering) ion source to implant into Si substrates to form shallow junctions. The use of boron containing cluster ions effectively reduces the boron energy while keeping the energy of the cluster ion beam at a high level. At the same time, it reduces the channeling effect due to amorphization by co-implanted heavy atoms like Ge and Si. Cluster ions have been used to produce 0.65--2keV boron for low energy ion implantation. Two stage annealing, which is a combination of low temperature (550°C) preannealing and high temperature annealing (1000°C), was carried out to anneal the Si sample implanted by GeB, SiBn clusters. The key concept of two-step annealing, that is, the separation of crystal regrowth, point defects removal with dopant activation from dopant diffusion, is discussed in detail. The advantages of the two stage annealing include better lattice structure, better dopant activation and retarded boron diffusion. The junction depth of the two stage annealed GeB sample was only half that of the one-step annealed sample, indicating that TED was suppressed by two stage annealing. Junction depths as small as 30 nm have been achieved by two stage annealing of sample implanted with 5 x 10-4/cm2 of 5 keV GeB at 1000°C for 1 second. The samples were evaluated by SIMS (secondary ion mass spectrometry) profiling, TEM (transmission electron microscopy) and RBS (Rutherford Backscattering Spectrometry)/channeling. Cluster ion implantation

  15. Determination of the dissociation constant of molten Li/sub 2/CO/sub 3//Na/sub 2/CO/sub 3//K/sub 2/CO/sub 3/ using a stabilized zirconia oxide-ion indicator

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Yasuhiko; Tsuru, Kiyoshi; Oishi, Jun; Miyazaki, Yoshinori; Kodama, Teruo

    1985-09-01

    An Li/sub 2/CO/sub 3//Na/sub 2/CO/sub 3//K/sub 2/CO/sub 3/ eutectic melt has been selected as an example of a molten-carbonate system and the suitability of a stabilized zirconia-air electrode as an oxide-ion concentration indicator for this melt has been confirmed. With this indicator, the dissociation constant of the reaction CO/sub 3//sup 2 -/(l)=CO/sub 2/(g)+O/sup 2 -/(l) in this melt has been determined to be Ksub(d)=P sub(CO/sub 2/) (O/sup 2 -/)=4.03 x 10/sup -3/ Pa at 873 K. Reproducible measurements were obtained throughout the experiment and this method might find further application in the study of reactions related to the oxide ion in carbonate melts. (orig.).

  16. In situ study of the effects of heavy-ion irradiation on co-evaporated CoSi2 films

    International Nuclear Information System (INIS)

    Allen, C.W.; Smith, D.A.

    1990-11-01

    The in situ ion irradiation capability of Argonne's HVEM-Tandem User Facility has been employed to determine the effects of 1.5 MeV Kr + irradiation and 300 kV electron irradiation on the crystallization of as-deposited and of partially crystallized 40 nm thick films of CoSi 2 . Ion fluxes ranged from 8.5 x 10 14 to 6.8 x 10 15 m -2 s -1 for which beam heating effects may be neglected. The maximum electron flux at 300 kV was 0.8 x 10 23 m -2 s -1 . The maximum temperature at which crystalline CoSi 2 is amorphized by the ion irradiation of flux = 6.8 x 10 15 m -2 s -1 is between 250 and 280 K. At higher temperatures amorphous material crystallizes by growth of any preexisting crystals and by classical nucleation and growth, with radial growth rates which are proportional to ion flux. The average degree of transformation per ion is 4 x 10 -26 m 3 per ion. Thermally induced crystallization of as-deposited films occurs above approximately 420 K. For ion doses at least as low as 3.4 x 10 16 m -2 ion irradiation at 300 K promotes thermal crystallization at 450 K, by virtue of enhanced apparant nucleation and at large doses, by enhanced growth rate. 8 refs., 2 figs

  17. A study of defect cluster formation in vanadium by heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sekimura, Naoto; Shirao, Yasuyuki; Morishita, Kazunori [Tokyo Univ. (Japan)

    1996-10-01

    Formation of defect clusters in thin foils of vanadium was investigated by heavy ion irradiation. In the very thin region of the specimens less than 20 nm, vacancy clusters were formed under gold ion irradiation, while very few clusters were detected in the specimens irradiated with 200 and 400 keV self-ions up to 1 x 10{sup 16} ions/m{sup 2}. The density of vacancy clusters were found to be strongly dependent on ion energy. Only above the critical value of kinetic energy transfer density in vanadium, vacancy clusters are considered to be formed in the cascade damage from which interstitials can escape to the specimen surface in the very thin region. (author)

  18. The economics of CO2-EOR cluster developments in the UK Central North Sea

    International Nuclear Information System (INIS)

    Kemp, Alexander G.; Kasim, Sola

    2013-01-01

    Studies to date have generally shown that individual CO 2 -EOR offshore projects are uneconomic except under questionable assumptions. The present study is based on an interconnected cluster of nine oilfields in the Central North Sea linked to an onshore CO 2 collection hub by a set of existing and new pipelines. Monte Carlo simulation modelling was undertaken of the prospective returns to investments in CO 2 -EOR in the fields. Relatively high oil prices were employed for the study period (2020–2050) and two contrasting CO 2 transfer price scenarios, the first being the Carbon Price Floor (CPF) introduced by the UK Government and the second being relatively low negotiated prices reflecting recent and prospective levels under the EU-ETS. At CPF prices the investment returns were all found to be negative, but at prices averaging £10 per tonne positive returns were generally achieved. The study emphasises the importance of CO 2 prices and the taxation system in determining the viability of the investments. - Highlights: • Detailed modelling of CO 2 EOR in nine North Sea oil fields. • Overall investment risks are demonstrated to be very high. • Sharing of pipelines in network and cluster of CO 2 -EOR fields significantly reduces investment costs. • Range of plausible CO 2 prices paid by investor results in very wide range of returns from CO 2 -EOR. • CO 2 pricing and tax arrangements for EOR need further attention by policy makers

  19. Porous MnCo2O4 as superior anode material over MnCo2O4 nanoparticles for rechargeable lithium ion batteries

    Science.gov (United States)

    Baji, Dona Susan; Jadhav, Harsharaj S.; Nair, Shantikumar V.; Rai, Alok Kumar

    2018-06-01

    Pyro synthesis is a method to coat nanoparticles by uniform layer of carbon without using any conventional carbon source. The resultant carbon coating can be evaporated in the form of CO or CO2 at high temperature with the creation of large number of nanopores on the sample surface. Hence, a porous MnCo2O4 is successfully synthesized here with the same above strategy. It is believed that the electrolyte can easily permeate through these nanopores into the bulk of the sample and allow rapid access of Li+ ions during charge/discharge cycling. In order to compare the superiority of the porous sample synthesized by pyro synthesis method, MnCo2O4 nanoparticles are also synthesized by sol-gel synthesis method at the same parameters. When tested as anode materials for lithium ion battery application, porous MnCo2O4 electrode shows high capacity with long lifespan at all the investigated current rates in comparison to MnCo2O4 nanoparticles electrode.

  20. Acceleration of cluster and molecular ions by TIARA 3 MV tandem accelerator

    CERN Document Server

    Saitoh, Y; Tajima, S

    2000-01-01

    We succeeded in accelerating molecular and cluster ions (B sub 2 sub - sub 4 , C sub 2 sub - sub 1 sub 0 , O sub 2 , Al sub 2 sub - sub 4 , Si sub 2 sub - sub 4 , Cu sub 2 sub - sub 3 , Au sub 2 sub - sub 3 , LiF, and AlO) to MeV energies with high-intensity beam currents by means of a 3 MV tandem accelerator in the TIARA facility. These cluster ions were generated by a cesium sputter-type negative ion source. We tested three types of carbon sputter cathodes in which graphite powder was compressed with different pressures. The pressure difference affected the generating ratio of clusters generated to single atom ions extracted from the source and it appeared that the high-density cathode was suitable. We also investigated the optimum gas pressure for charge exchange in the tandem high-voltage terminal. Clusters of larger size tend to require lower pressure than do smaller ones. In addition, we were able to obtain doubly charged AlO molecular ions. (authors)

  1. Experimental investigations of hydrogen cluster ions

    International Nuclear Information System (INIS)

    Lumig, H.A. van.

    1978-01-01

    Experiments to obtain information about the structure and stability of small hydrogen cluster ions have been performed. Attenuation and fragmentation measurements are presented of hydrogen cluster ions colliding with nitrogen, argon, hydrogen and helium over fixed energy ranges. The total collision and differential fragmentation cross sections are tabulated. (C.F.)

  2. Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Nicholas B. [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln11]-amyloid β-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will

  3. Hard-X-ray photoelectron spectroscopy of NaxCoO2.yH2O

    International Nuclear Information System (INIS)

    Chainani, A.; Yokoya, T.; Takata, Y.; Tamasaku, K.; Taguchi, M.; Shimojima, T.; Kamakura, N.; Horiba, K.; Tsuda, S.; Shin, S.; Miwa, D.; Nishino, Y.; Ishikawa, T.; Yabashi, M.; Kobayashi, K.; Namatame, H.; Taniguchi, M.; Takada, K.; Sasaki, T.; Sakurai, H.; Takayama-Muromachi, E.

    2005-01-01

    We study the bulk electronic structure of Na x CoO 2 .yH 2 O using Hard X-ray (HX, hν = 5.95KeV) synchrotron photoelectron spectroscopy (PES). The Co 2p core level spectra show well-separated Co 3+ and Co 4+ ions. Cluster calculations suggest low spin Co 3+ and Co 4+ character, and a moderate on-site Coulomb correlation energy U dd ∼3-5.5eV. Photon-dependent valence band PES identifies Co 3d and O 2p derived states, in near agreement with band structure calculations. We discuss the importance of HX-PES for studying correlated transition metal oxides

  4. Some properties of ion and cluster plasma

    International Nuclear Information System (INIS)

    Gudzenko, L.I.; Derzhiev, V.I.; Yakovlenko, S.I.

    1982-01-01

    The aggregate of problems connected with the physics of ion and cluster plasma is qualitatively considered. Such a plasma can exist when a dense gas is ionized by a hard ionizer. The conditions for the formation of an ion plasma and the difference between its characteristics and those of an ordinary electron plasma are discussed; a solvated-ion model and the distribution of the clusters with respect to the number of solvated molecules are considered. The recombination rate of the positively and negatively charged clusters is roughly estimated. The parameters of a ball-lightning plasma are estimated on the basis of the cluster model

  5. Fischer-Tropsch synthesis: Support and cobalt cluster size effects on kinetics over Co/Al{sub 2}O{sub 3} and Co/SiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wenping Ma; Gary Jacobs; Dennis E. Sparks; Muthu K. Gnanamani; Venkat Ramana Rao Pendyala; Chia H. Yen; Jennifer L.S. Klettlinger; Thomas M. Tomsik; Burtron H. Davis [University of Kentucky, Lexington, KY (USA). Center for Applied Energy Research

    2011-02-15

    The influence of support type and cobalt cluster size (i.e., with average diameters falling within the range of 8-40 nm) on the kinetics of Fischer-Tropsch synthesis (FT) were investigated by kinetic tests employing a CSTR and two Co/{gamma}-Al{sub 2}O{sub 3} catalysts having different average pore sizes, and two Co/SiO{sub 2} catalysts prepared on the same support but having different loadings. A kinetic model -r{sub CO}=kP{sup a}{sub co}P{sup b}{sub H2}/(1 + mP{sub H2O}/P{sub H2}) that contains a water effect constant 'm' was used to fit the experimental data obtained with all four catalysts. Kinetic parameters suggest that both support type and average Co particle size impact FT behavior. Cobalt cluster size influenced kinetic parameters such as reaction order, rate constant, and the water effect parameter.Decreasing the average Co cluster diameter by about 30% led to an increase in the intrinsic reaction rate constant k, defined on a per g of catalyst basis, by 62-102% for the {gamma}-Al{sub 2}O{sub 3} and SiO{sub 2}-supported cobalt catalysts. Moreover, less inhibition by adsorbed CO and greater H{sub 2} dissociation on catalysts having smaller Co particles was suggested by the higher a and lower b values obtained for the measured reaction orders. Irrespective of support type, the catalysts having smaller average Co particles were more sensitive to water. Comparing the catalysts having strong interactions between cobalt and support (Co/Al{sub 2}O{sub 3}) to the ones with weak interactions (Co/SiO{sub 2}), the water effect parameters were found to be positive (indicating a negative influence on CO conversion) and negative (denoting a positive effect on CO conversion), respectively. Greater a and a/b values were observed for both Al{sub 2}O{sub 3}-supported Co catalysts, implying greater inhibition of the FT rate by strongly adsorbed CO on Co/Al{sub 2}O{sub 3} relative to Co/SiO{sub 2}. 78 refs., 4 figs., 3 tabs.

  6. Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

    Science.gov (United States)

    Kal, S.; Kasko, I.; Ryssel, H.

    1995-10-01

    The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (micrographs of the ion-beam mixed and unmixed CoSi2 films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

  7. Ion beam induced nanosized Ag metal clusters in glass

    International Nuclear Information System (INIS)

    Mahnke, H.-E.; Schattat, B.; Schubert-Bischoff, P.; Novakovic, N.

    2006-01-01

    Silver metal clusters have been formed in soda lime glass by high-energy heavy-ion irradiation at ISL. The metal cluster formation was detected with X-ray absorption spectroscopy (EXAFS) in fluorescence mode, and the shape of the clusters was imaged with transmission electron microscopy. While annealing in reducing atmosphere alone, leads to the formation of metal clusters in Ag-containing glasses, where the Ag was introduced by ion-exchange, such clusters are not very uniform in size and are randomly distributed over the Ag-containing glass volume. Irradiation with 600-MeV Au ions followed by annealing, however, results in clusters more uniform in size and arranged in chains parallel to the direction of the ion beam

  8. Renewable Formate from C-H Bond Formation with CO2: Using Iron Carbonyl Clusters as Electrocatalysts.

    Science.gov (United States)

    Loewen, Natalia D; Neelakantan, Taruna V; Berben, Louise A

    2017-09-19

    As a society, we are heavily dependent on nonrenewable petroleum-derived fuels and chemical feedstocks. Rapid depletion of these resources and the increasingly evident negative effects of excess atmospheric CO 2 drive our efforts to discover ways of converting excess CO 2 into energy dense chemical fuels through selective C-H bond formation and using renewable energy sources to supply electrons. In this way, a carbon-neutral fuel economy might be realized. To develop a molecular or heterogeneous catalyst for C-H bond formation with CO 2 requires a fundamental understanding of how to generate metal hydrides that selectively donate H - to CO 2 , rather than recombining with H + to liberate H 2 . Our work with a unique series of water-soluble and -stable, low-valent iron electrocatalysts offers mechanistic and thermochemical insights into formate production from CO 2 . Of particular interest are the nitride- and carbide-containing clusters: [Fe 4 N(CO) 12 ] - and its derivatives and [Fe 4 C(CO) 12 ] 2- . In both aqueous and mixed solvent conditions, [Fe 4 N(CO) 12 ] - forms a reduced hydride intermediate, [H-Fe 4 N(CO) 12 ] - , through stepwise electron and proton transfers. This hydride selectively reacts with CO 2 and generates formate with >95% efficiency. The mechanism for this transformation is supported by crystallographic, cyclic voltammetry, and spectroelectrochemical (SEC) evidence. Furthermore, installation of a proton shuttle onto [Fe 4 N(CO) 12 ] - facilitates proton transfer to the active site, successfully intercepting the hydride intermediate before it reacts with CO 2 ; only H 2 is observed in this case. In contrast, isoelectronic [Fe 4 C(CO) 12 ] 2- features a concerted proton-electron transfer mechanism to form [H-Fe 4 C(CO) 12 ] 2- , which is selective for H 2 production even in the presence of CO 2 , in both aqueous and mixed solvent systems. Higher nuclearity clusters were also studied, and all are proton reduction electrocatalysts, but none

  9. Fullerene nanostructure design with cluster ion impacts

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.; Narumi, K.

    2009-01-01

    Roč. 483, - (2009), s. 479-483 ISSN 0925-8388 R&D Projects: GA AV ČR IAA200480702; GA AV ČR IAA400100701; GA AV ČR(CZ) KAN400480701 Institutional research plan: CEZ:AV0Z10480505 Keywords : fullerene films, clusters C60+ * cluster ion implantation * patterning Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.135, year: 2009

  10. Comparison of Se and Te clusters produced by ion bombardment

    Directory of Open Access Journals (Sweden)

    Trzyna Małgorzata

    2017-01-01

    Full Text Available Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS. It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to ~ 1300 m/z. Local maxima or minima (magic numbers are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  11. Comparison of Se and Te clusters produced by ion bombardment

    Science.gov (United States)

    Trzyna, Małgorzata

    2017-01-01

    Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS). It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to 1300 m/z. Local maxima or minima (magic numbers) are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  12. 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...

  13. The local environment of cobalt in amorphous, polycrystalline and epitaxial anatase TiO{sub 2}:Co films produced by cobalt ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Yildirim, O. [Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, 01328 Dresden (Germany); Technische Universität Dresden, D-01062 Dresden (Germany); Cornelius, S.; Hübner, R.; Potzger, K. [Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, 01328 Dresden (Germany); Smekhova, A.; Zykov, G.; Gan' shina, E. A.; Granovsky, A. B. [Lomonosov Moscow State University (MSU), Faculty of Physics, 119991 Moscow (Russian Federation); Bähtz, C. [Helmholtz-Zentrum Dresden - Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstr. 400, 01328 Dresden (Germany); Rossendorf Beamline, European Synchrotron Radiation Facility, F-38043 Grenoble (France)

    2015-05-14

    Amorphous, polycrystalline anatase and epitaxial anatase TiO{sub 2} films have been implanted with 5 at. % Co{sup +}. The magnetic and structural properties of different microstructures of TiO{sub 2}:Co, along with the local coordination of the implanted Co atoms within the host lattice are investigated. In amorphous TiO{sub 2}:Co film, Co atoms are in the (II) oxidation state with a complex coordination and exhibit a paramagnetic response. However, for the TiO{sub 2}:Co epitaxial and polycrystalline anatase films, Co atoms have a distorted octahedral (II) oxygen coordination assigned to a substitutional environment with traces of metallic Co clusters, which gives a rise to a superparamagnetic behavior. Despite the incorporation of the implanted atoms into the host lattice, high temperature ferromagnetism is absent in the films. On the other hand, it is found that the concentration and size of the implantation-induced nanoclusters and the magnetic properties of TiO{sub 2}:Co films have a strong dependency on the initial microstructure of TiO{sub 2}. Consequently, metallic nanocluster formation within ion implantation prepared transition metal doped TiO{sub 2} can be suppressed by tuning the film microstructure.

  14. Group IIB-VIA semiconductor oxide cluster ions

    Science.gov (United States)

    Jayasekharan, Thankan

    2018-05-01

    Metal oxide cluster ions, MnOm± (M = Zn, Cd) and HgnOm- of various stoichiometry have been generated from solid IIB-VIA semiconductor oxides targets, (ZnO(s), CdO(s), and HgO(s)) by using pulse laser desorption ionization time of flight mass spectrometry with a laser of λ = 355 nm. Analysis of mass spectral data indicates the formation of stoichiometric cluster ions viz., (ZnO)n=1-30+ and (CdO)n=1-40+ along with -O bound anions, (ZnO)n=1-30O-, (CdO)n=1-40O- and (HgO)n=1-36O- from their respective solids. Further, metal oxoanions such as ZnOn=2,3-, CdOn=2,3,6-, and HgOn=2,3,6,7- have also been noted signifying the higher coordination ability of both Cd and Hg with O/O2/O3 species.

  15. Reactions of mixed silver-gold cluster cations AgmAun+ (m+n=4,5,6) with CO: Radiative association kinetics and density functional theory computations

    International Nuclear Information System (INIS)

    Neumaier, Marco; Weigend, Florian; Hampe, Oliver; Kappes, Manfred M.

    2006-01-01

    Near thermal energy reactive collisions of small mixed metal cluster cations Ag m Au n + (m+n=4, 5, and 6) with carbon monoxide have been studied in the room temperature Penning trap of a Fourier transform ion-cyclotron-resonance mass spectrometer as a function of cluster size and composition. The tetrameric species AgAu 3 + and Ag 2 Au 2 + are found to react dissociatively by way of Au or Ag atom loss, respectively, to form the cluster carbonyl AgAu 2 CO + . In contrast, measurements on a selection of pentamers and hexamers show that CO is added with absolute rate constants that decrease with increasing silver content. Experimentally determined absolute rate constants for CO adsorption were analyzed using the radiative association kinetics model to obtain cluster cation-CO binding energies ranging from 0.77 to 1.09 eV. High-level ab initio density functional theory (DFT) computations identifying the lowest-energy cluster isomers and the respective CO adsorption energies are in good agreement with the experimental findings clearly showing that CO binds in a ''head-on'' fashion to a gold atom in the mixed clusters. DFT exploration of reaction pathways in the case of Ag 2 Au 2 + suggests that exoergicities are high enough to access the minimum energy products for all reactive clusters probed

  16. Reactions of mixed silver-gold cluster cations AgmAun+ (m+n=4,5,6) with CO: Radiative association kinetics and density functional theory computations

    Science.gov (United States)

    Neumaier, Marco; Weigend, Florian; Hampe, Oliver; Kappes, Manfred M.

    2006-09-01

    Near thermal energy reactive collisions of small mixed metal cluster cations AgmAun+ (m +n=4, 5, and 6) with carbon monoxide have been studied in the room temperature Penning trap of a Fourier transform ion-cyclotron-resonance mass spectrometer as a function of cluster size and composition. The tetrameric species AgAu3+ and Ag2Au2+ are found to react dissociatively by way of Au or Ag atom loss, respectively, to form the cluster carbonyl AgAu2CO+. In contrast, measurements on a selection of pentamers and hexamers show that CO is added with absolute rate constants that decrease with increasing silver content. Experimentally determined absolute rate constants for CO adsorption were analyzed using the radiative association kinetics model to obtain cluster cation-CO binding energies ranging from 0.77to1.09eV. High-level ab initio density functional theory (DFT) computations identifying the lowest-energy cluster isomers and the respective CO adsorption energies are in good agreement with the experimental findings clearly showing that CO binds in a "head-on" fashion to a gold atom in the mixed clusters. DFT exploration of reaction pathways in the case of Ag2Au2+ suggests that exoergicities are high enough to access the minimum energy products for all reactive clusters probed.

  17. XPS investigation of monatomic and cluster argon ion sputtering of tantalum pentoxide

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Robin, E-mail: r.simpson@surrey.ac.uk [The Surface Analysis Laboratory, Department of Mechanical Engineering Sciences, University of Surrey (United Kingdom); Thermo Scientific, East Grinstead (United Kingdom); White, Richard G. [Thermo Scientific, East Grinstead (United Kingdom); Watts, John F.; Baker, Mark A. [The Surface Analysis Laboratory, Department of Mechanical Engineering Sciences, University of Surrey (United Kingdom)

    2017-05-31

    Highlights: • Ion beam induced oxide reduction from monatomic and gas cluster ion beam exposure are compared. • Lower relative level of preferential sputtering is shown in gas cluster ion beam depth profiling. • A lack of “steady state” is observed in gas cluster ion beam depth profiles of tantalum pentoxide. • Possible mechanisms behind the observed results, including temperature effects are proposed. - Abstract: In recent years, gas cluster ion beams (GCIB) have become the cutting edge of ion beam technology to sputter etch organic materials in surface analysis. However, little is currently known on the ability of argon cluster ions (Ar{sub n}{sup +}) to etch metal oxides and other technologically important inorganic compounds and no depth profiles have previously been reported. In this work, XPS depth profiles through a certified (European standard BCR-261T) 30 nm thick Ta{sub 2}O{sub 5} layer grown on Ta foil using monatomic Ar{sup +} and Ar{sub 1000}{sup +} cluster ions have been performed at different incident energies. The preferential sputtering of oxygen induced using 6 keV Ar{sub 1000}{sup +} ions is lower relative to 3 keV and 500 eV Ar{sup +} ions. Ar{sup +} ions exhibit a steady state O/Ta ratio through the bulk oxide but Ar{sub 1000}{sup +} ions show a gradual decrease in the O/Ta ratio as a function of depth. The depth resolution and etch rate is substantially better for the monatomic beam compared to the cluster beam. Higher O concentrations are observed when the underlying Ta bulk metal is sputtered for the Ar{sub 1000}{sup +} profiles compared to the Ar{sup +} profiles.

  18. Composition dependent selectivity in the coadsorption of H2O and CO on pure and binary silver-gold clusters

    Science.gov (United States)

    Fleischer, Irene; Popolan, Denisia M.; Krstić, Marjan; Bonačić-Koutecký, Vlasta; Bernhardt, Thorsten M.

    2013-04-01

    Small cationic gold clusters exhibit a strong affinity toward carbon monoxide. This prevents the coadsorption of water which would be the first step of a catalytic water gas shift chemistry on these clusters. In a gas phase ion trap experiment with mass selected AgnAum+ it was however possible to demonstrate that the replacement of gold by silver atoms in triatomic cluster ions liberates sites for H2O adsorption. The resulting observed coadsorption effect occurs at a cross-over in the molecular binding energies of carbon monoxide and water to these clusters determined by reaction kinetics measurements and first principles calculations.

  19. Photodissociation spectroscopy of the Mg + -CO2 complex and its isotopic analogs

    Science.gov (United States)

    Yeh, C. S.; Willey, K. F.; Robbins, D. L.; Pilgrim, J. S.; Duncan, M. A.

    1993-02-01

    Mg+-CO2 ion-molecule cluster complexes are produced by laser vaporization in a pulsed nozzle cluster source. The vibronic spectroscopy in these complexes is studied with mass-selected photodissociation spectroscopy in a reflectron time-of-flight mass spectrometer. Two excited electronic states are observed (2) 2Σ+ and 2Π. The 2Π state has a vibrational progression in the metal-CO2 stretching mode (ωe'=381.8 cm-1). The complexes are linear (Mg+-OCO) and are bound by the charge-quadrupole interaction. The dissociation energy (D0`) is 14.7 kcal/mol. Corresponding spectra are measured for each of the 24, 25, and 26 isotopes of magnesium. These results are compared to theoretical predictions made by Bauschlicher and co-workers.

  20. Alternative synthetic route for the heterometallic CO-releasing [Sb@Rh12(CO27]3− icosahedral carbonyl cluster and synthesis of its new unsaturated [Sb@Rh12(CO24]4− and dimeric [{Sb@Rh12Sb(CO25}2Rh(CO2PPh3]7− derivatives

    Directory of Open Access Journals (Sweden)

    Cristina Femoni

    2016-10-01

    Full Text Available The hetero-metallic [Sb@Rh12(CO27]3− cluster has been known as for over three decades thanks to Vidal and co-workers, and represents the first example of an E-centered (E=heteroatom icosahedral rhodium carbonyl cluster. However, its synthesis required high temperature (140–160 °C and elevated CO pressure (400 atm. Applying the redox condensation method for cluster preparation, we herein report a new synthetic, high-yield route for preparing [Sb@Rh12(CO27]3− under much milder conditions of temperature and pressure. Notably, when the same synthesis was carried out under N2 instead of CO atmosphere, the new isostructural but unsaturated derivative [Sb@Rh12(CO24]4− was obtained, for which we report the full X-ray structural characterization. This species represents one of the few examples of an icosahedral cluster disobeying the electron-counting Wade-Mingos rules, possessing less than the expected 170 cluster valence electrons (CVEs. Judging from IR monitoring, the two species can be obtained one from the other by switching between N2 and CO atmosphere, making [Sb@Rh12(CO27]3− a spontaneous CO-releasing molecule. Finally, the study of the chemical reactivity of [Sb@Rh12(CO27]3− with PPh3 allowed us to obtain the new [{Sb@Rh12Sb(CO25}2Rh(CO2PPh3]7− dimeric compound, for which we herein report the full X-ray structural and 31P NMR analyses.

  1. Photocatalytic properties of Co_3O_4/LiCoO_2 recycled from spent lithium-ion batteries using citric acid as leaching agent

    International Nuclear Information System (INIS)

    Santana, I.L.; Moreira, T.F.M.; Lelis, M.F.F.; Freitas, M.B.J.G.

    2017-01-01

    In this work, cobalt and lithium from the cathodes of spent lithium-ion batteries were recycled to synthesize a mixture of Co_3O_4 and LiCoO_2. The positive electrode was leached with citric acid in the green recycling. After being heated to 85 °C, the leaching solution formed a pink sol, and after being dried at 120 °C for 24 h, it formed a gel, which is a precursor material for Co_3O_4 and LiCoO_2 synthesis. A mixture of Co_3O_4 and LT-LiCoO_2 was obtained after the calcination of the precursor material at 450 °C for 3 h. The photocatalytic properties of the Co_3O_4 and LiCoO_2 were tested in the discoloration of methylene blue dye. The discoloration efficiency of methylene blue dye in the presence of Co_3O_4 and LiCoO_2 was 90% after 10 h and 100% after 24 h of heterogeneous catalysis. The contribution of this work is that it presents a means to produce valuable materials with photocatalytic properties from recycled batteries through a spent Li-ion battery recycling process without polluting the environment. - Highlights: • Synthesis a mixture of Co_3O_4/LiCoO_2 from spent Li-ion batteries. • Citric acid for leaching of the cathodes of the spent Li-ion batteries. • Co_3O_4/LiCoO_2 as catalysts in the photodegradation of the methylene blue dye.

  2. Structural study of CH4, CO2 and H2O clusters containing from several tens to several thousands of molecules

    Science.gov (United States)

    Torchet, G.; Farges, J.; de Feraudy, M. F.; Raoult, B.

    Clusters are produced during the free jet expansion of gaseous CH4, CO2 or H2O. For a given stagnation temperature To, the mean cluster size is easily increased by increasing the stagnation pressure p0. On the other hand, the cluster temperature does not depend on stagnation conditions but mainly on properties of the condensed gas. An electron diffraction analysis provides information about the cluster structure. Depending on whether the diffraction patterns exhibit crystalline lines or not, the structure is worked out either by using crystallographic methods or by constructing cluster models. When they contain more than a few thousand molecules, clusters show a crystalline structure identical to that of one phase, namely, the cubic phase, known in bulk solid: plastic phase (CH4), unique solid phase (CO2) or metastable cubic phase (H2O). When decreasing the cluster size, the studied compounds behave quite differently: CO2 clusters keep the same crystalline structure, CH4 clusters show the multilayer icosahedral structure wich has been found in rare gas clusters, and H2O clusters adopt a disordered structure different from the amorphous structures of bulk ice. Des agrégats sont produits au cours de la détente en jet libre des gaz CH4, CO2 ou H2O. Pour une température initiale donnée To, on accroît facilement la taille moyenne des agrégats en augmentant la pression initiale po . Par contre, la température des agrégats dépend principalement des propriétés du gaz condensé. Une analyse par diffraction électronique permet l'étude de la structure des agrégats. Selon que les diagrammes de diffraction contiennent ou non des raies cristallines, on a recours soit à des méthodes cristallographiques soit à la construction de modèles d'agrégats. Lorsqu'ils renferment plus de quelques milliers de molécules, les agrégats adoptent la structure cristalline de l'une des phases connues du solide massif et plus précisément la phase cubique : phase plastique pour

  3. Observation of ions with energies above 100 keV produced by the interaction of a 60-fs laser pulse with clusters

    International Nuclear Information System (INIS)

    Dobosz, S.; Schmidt, M.; Perdrix, M.; Meynadier, P.; Gobert, O.; Normand, D.; Ellert, K.; Blenski, T.; Faenov, A.Ya.; Magunov, A.I.; Pikuz, T.A.; Skobelev, I.Yu.; Andreev, N.E.

    1999-01-01

    The x-ray spectra of a plasma generated by heating CO 2 and Ar clusters with high-intensity femtosecond laser pulses with q las ≅10 18 W/cm 2 are investigated. Spatially resolved x-ray spectra of a cluster plasma are obtained for the first time. Photoionization absorption is observed to influence the spectral line profiles. The recorded features of the x-ray emission spectra definitely indicate the existence of a large relative number of excited ions (≅10 -2 -10 -3 ) with energies of 0.1-1 MeV in such a plasma. Possible mechanisms underlying the acceleration of ions to high energies are discussed. It is shown that the experimental results can be attributed to the influence of ponderomotive forces in standing waves generated by the reflection of laser radiation from the clusters

  4. Competition Between Co(NH3)63+ and Inner Sphere Mg2+ Ions in the HDV Ribozyme

    Science.gov (United States)

    Gong, Bo; Chen, Jui-Hui; Bevilacqua, Philip C.; Golden, Barbara L.; Carey, Paul R.

    2009-01-01

    Divalent cations play critical structural and functional roles in many RNAs. While the hepatitis delta virus (HDV) ribozyme can undergo self-cleavage in the presence of molar concentrations of monovalent cations, divalent cations such as Mg2+ are required for efficient catalysis under physiological conditions. Moreover, the cleavage reaction can be inhibited with Co(NH3)63+, an analog of Mg(H2O)62+. Here, the binding of Mg2+ and Co(NH3)63+ to the HDV ribozyme are studied by Raman microscopic analysis of crystals. Raman difference spectra acquired at different metal ion conditions reveal changes in the ribozyme. When Mg2+ alone is introduced to the ribozyme, inner sphere coordination of Mg(H2O)x2+ (x≤5) to non-bridging PO2− oxygen, and changes in base stretches and phosphodiester group conformation are observed. In addition, binding of Mg2+ induces deprotonation of a cytosine assigned to the general acid C75, consistent with solution studies. When Co(NH3)63+ alone is introduced, deprotonation of C75 is again observed, as are distinctive changes in base vibrational ring modes and phosphodiester backbone conformation. In contrast to Mg2+ binding, Co(NH3)63+ binding does not perturb PO2− group vibrations, consistent with its ability to make only outer sphere contacts. Surprisingly, competitive binding studies reveal that Co(NH3)63+ ions displace some inner sphere-coordinated magnesium species, including ions coordinated to PO2− groups or the N7 of a guanine, likely G1 at the active site. These observations contrast with the tenet that Co(NH3)63+ ions displace only outer sphere magnesium ions. Overall, our data support two classes of inner sphere Mg2+-PO2− binding sites: sites that Co(NH3)63+ can displace, and others it cannot. PMID:19888753

  5. Electrochemical potassium-ion intercalation in NaxCoO2: a novel cathode material for potassium-ion batteries.

    Science.gov (United States)

    Sada, Krishnakanth; Senthilkumar, Baskar; Barpanda, Prabeer

    2017-07-27

    Reversible electrochemical potassium-ion intercalation in P2-type Na x CoO 2 was examined for the first time. Hexagonal Na 0.84 CoO 2 platelets prepared by a solution combustion synthesis technique were found to work as an efficient host for K + intercalation. They deliver a high reversible capacity of 82 mA h g -1 , good rate capability and excellent cycling performance up to 50 cycles.

  6. Solvothermal Synthesis, Crystal Structure, and Magnetic Properties of [Co3(SDA)3(DMF)2]: 2-D Layered Metal-organic Framework Derived from 4,4'-Stilbenedicarboxylic Acid (H2SDA)

    International Nuclear Information System (INIS)

    Park, Gyung Se; Kim, Hyun Uk; Kim, Ki Moon; Lee, Gang Ho; Park, Sang Kyu

    2006-01-01

    A new 2-D coordination polymer has been synthesized and characterized by using a novel 4,4'-stilbene dicarboxylic acid and Co(ClO 4 ) 2 ·6H 2 O. The title complex has an unique Co 3 pin-wheel cluster in which central Co has octahedral geometry and two surrounding Co have tetrahedral geometry. The Co 3 pin-wheel clusters, the building unit, are linked through carboxylate oxygens to generate a 2-D layered coordination polymer in ABCABC packing mode. Variable-temperature magnetic susceptibility data of the title compound confirms the high spin splitting of Co with S=3/2. Syntheses of MOF by using SDA and other transition metal ions, Zn, Cd, and Mn, are on progress in this lab. Metal-organic frameworks (MOF) have attracted much more attention in the past decade owing to their various intriguing framework topologies and potential applications as functional materials in gas storage, separation, and catalysis. Because high framework stability is fundamental and essential property for many practical applications, multi-dentate linkers such as carboxylates have been extensively investigated for the formation of more rigid frameworks due to their ability to aggregate metal ions into M-O-C clusters called secondary building units (SBUs) rather than N-bound organic linkers such as 4,4-bipyridine (bipy)

  7. Co-clustering models, algorithms and applications

    CERN Document Server

    Govaert, Gérard

    2013-01-01

    Cluster or co-cluster analyses are important tools in a variety of scientific areas. The introduction of this book presents a state of the art of already well-established, as well as more recent methods of co-clustering. The authors mainly deal with the two-mode partitioning under different approaches, but pay particular attention to a probabilistic approach. Chapter 1 concerns clustering in general and the model-based clustering in particular. The authors briefly review the classical clustering methods and focus on the mixture model. They present and discuss the use of different mixture

  8. Oxygen, hydrogen, ethylene and CO 2 development in lithium-ion batteries

    Science.gov (United States)

    Holzapfel, M.; Würsig, A.; Scheifele, W.; Vetter, J.; Novák, P.

    Gas evolution has been examined for different types of battery-related electrode materials via in situ differential electrochemical mass spectrometry (DEMS). Besides standard graphite also a novel silicon-based negative electrode was examined and it was shown that the evolution of hydrogen and ethylene is considerably reduced on this material compared to graphite. Oxygen evolution was proven to happen on the oxidative reaction of a Li 2O 2 electrode, besides a certain oxidation of the electrolyte. The 4.5 V plateau upon the oxidation of Li[Ni 0.2Li 0.2Mn 0.6]O 2 was likewise proven to be linked to oxygen evolution. Also in this case electrolyte oxidation was shown to be a side reaction. Layered positive electrode materials Li(Ni,Co,Al)O 2 and Li(Ni,Mn,Co)O 2 were also examined. The influence of different parameters on the CO 2 evolution in lithium-ion batteries was shown up. The amount of CO 2 formation is increased by high temperatures and cell voltages, while the addition of vinylene carbonate (VC) decreases it. Li(Ni,Mn,Co)O 2 shows much less CO 2 evolution than Li(Ni,Co,Al)O 2.

  9. Visualization of DNA clustered damage induced by heavy ion exposure

    International Nuclear Information System (INIS)

    Tomita, M.; Yatagai, F.

    2003-01-01

    Full text: DNA double-strand breaks (DSBs) are the most lethal damage induced by ionizing radiations. Accelerated heavy-ions have been shown to induce DNA clustered damage, which is two or more DNA lesions induced within a few helical turns. Higher biological effectiveness of heavy-ions could be provided predominantly by induction of complex DNA clustered damage, which leads to non-repairable DSBs. DNA-dependent protein kinase (DNA-PK) is composed of catalytic subunit (DNA-PKcs) and DNA-binding heterodimer (Ku70 and Ku86). DNA-PK acts as a sensor of DSB during non-homologous end-joining (NHEJ), since DNA-PK is activated to bind to the ends of double-stranded DNA. On the other hand, NBS1 and histone H2AX are essential for DSB repair by homologous recombination (HR) in higher vertebrate cells. Here we report that phosphorylated H2AX at Ser139 (named γ-H2AX) and NBS1 form large undissolvable foci after exposure to accelerated Fe ions, while DNA-PKcs does not recognize DNA clustered damage. NBS1 and γ-H2AX colocalized with forming discrete foci after exposure to X-rays. At 0.5 h after Fe ion irradiation, NBS1 and γ-H2AX also formed discrete foci. However, at 3-8 h after Fe ion irradiation, highly localized large foci turned up, while small discrete foci disappeared. Large NBS1 and γ-H2AX foci were remained even 16 h after irradiation. DNA-PKcs recognized Ku-binding DSB and formed foci shortly after exposure to X-rays. DNA-PKcs foci were observed 0.5 h after 5 Gy of Fe ion irradiation and were almost completely disappeared up to 8 h. These results suggest that NBS1 and γ-H2AX can be utilized as molecular marker of DNA clustered damage, while DNA-PK selectively recognizes repairable DSBs by NHEJ

  10. METI/NEDO Projects on Cluster Ion Beam Process Technology

    International Nuclear Information System (INIS)

    Yamada, Isao; Matsuo, Jiro; Toyoda, Noriaki

    2003-01-01

    Since the initial study of gas cluster ion beams (GCIB) was started in the Ion Beam Engineering Experimental Laboratory of Kyoto University, more than 15 years have passed. Some of the results of that study have already been applied for industrial use. Unique characteristics of gas cluster ion bombardment have been found to offer potential for various other industrial applications. The impact of an accelerated cluster ion upon a target surface imparts very high energy densities into the impact area and produces non-linear effects that are not associated with the impacts of atomic ions. Among prospective applications for these effects are included shallow ion implantation, high rate sputtering, surface cleaning and smoothing, and low temperature thin film formation

  11. Ionization and fragmentation of water clusters by fast highly charged ions

    International Nuclear Information System (INIS)

    Adoui, L; Cassimi, A; Gervais, B; Grandin, J-P; Guillaume, L; Maisonny, R; Legendre, S; Tarisien, M; Lopez-Tarifa, P; Alcami, M; Martin, F; Politis, M-F; Penhoat, M-A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study the dissociative ionization of water clusters by impact of 12 MeV/u Ni 25+ ions. Cold target recoil ion momentum spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized water clusters. An unusual stability of the H 9 O + 4 ion is observed, which could be the signature of the so-called Eigen structure in gas-phase water clusters. From the analysis of coincidences between charged fragments, we conclude that charge mobility is very high and is responsible for the formation of protonated water clusters, (H 2 O) n H + , that dominate the mass spectrum. These results are supported by Car-Parrinello molecular dynamics and time-dependent density functional theory simulations, which also reveal the mechanisms of such mobility.

  12. One-step synthesis of SnCo nanoconfined in hierarchical carbon nanostructures for lithium ion battery anode.

    Science.gov (United States)

    Qin, Jian; Liu, Dongye; Zhang, Xiang; Zhao, Naiqin; Shi, Chunsheng; Liu, En-Zuo; He, Fang; Ma, Liying; Li, Qunying; Li, Jiajun; He, Chunnian

    2017-10-26

    A new strategy for the one-step synthesis of a 0D SnCo nanoparticles-1D carbon nanotubes-3D hollow carbon submicrocube cluster (denoted as SnCo@CNT-3DC) hierarchical nanostructured material was developed via a simple chemical vapor deposition (CVD) process with the assistance of a water-soluble salt (NaCl). The adopted NaCl not only acted as a cubic template for inducing the formation of the 3D hollow carbon submicrocube cluster but also provides a substrate for the SnCo catalysts impregnation and CNT growth, ultimately leading to the successful construction of the unique 0D-1D-3D structured SnCo@CNT-3DC during the CVD of C 2 H 2 . When utilized as a lithium-ion battery anode, the SnCo@CNT-3DC composite electrode demonstrated an excellent rate performance and cycling stability for Li-ion storage. Specifically, an impressive reversible capacity of 826 mA h g -1 after 100 cycles at 0.1 A g -1 and a high rate capacity of 278 mA h g -1 even after 1000 cycles at 5 A g -1 were achieved. This remarkable electrochemical performance could be ascribed to the unique hierarchical nanostructure of SnCo@CNT-3DC, which guarantees a deep permeation of electrolytes and a shortened lithium salt diffusion pathway in the solid phase as well as numerous hyperchannels for electron transfer.

  13. Oxide ion diffusion mechanism related to Co and Fe ions in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ using in-situ X-ray absorption spectroscopy

    Science.gov (United States)

    Itoh, Takanori; Imai, Hideto

    2018-03-01

    The time changes of the white line and pre-edge intensities of Co and Fe K-edge in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ (BSCF) were observed to estimate the oxide ion diffusion related to Co and Fe ions by using in - situ X-ray absorption spectroscopy (XAS) during oxidation. The 20 μm self-standing BSCF film was prepared for in - situ XAS measurements. The time changes of absorption were fitted to the exponential decay function with two terms. The longer relaxation time (τ), related to the oxide ion diffusion during the oxidation of BSCF, is dependent on temperature. The oxide ion diffusion coefficients (D) were calculated from the τ s estimated by in - situ XAS. The values of the activation energy (Ea) for D related to Co K-edge white line, Co pre-edge, and Fe pre-edge were 1.8-2.0 eV. The value of Ea for D related to Fe K-edge white line, however, was higher than other absorption values at approximately 2.3 eV. We discussed the oxide ion diffusion mechanism related to Co and Fe ions in BSCF using in - situ XAS.

  14. Ion induced electron emission statistics under Agm- cluster bombardment of Ag

    Science.gov (United States)

    Breuers, A.; Penning, R.; Wucher, A.

    2018-05-01

    The electron emission from a polycrystalline silver surface under bombardment with Agm- cluster ions (m = 1, 2, 3) is investigated in terms of ion induced kinetic excitation. The electron yield γ is determined directly by a current measurement method on the one hand and implicitly by the analysis of the electron emission statistics on the other hand. Successful measurements of the electron emission spectra ensure a deeper understanding of the ion induced kinetic electron emission process, with particular emphasis on the effect of the projectile cluster size to the yield as well as to emission statistics. The results allow a quantitative comparison to computer simulations performed for silver atoms and clusters impinging onto a silver surface.

  15. Formation of positive cluster ions Li(n) Br (n = 2-7) and ionization energies studied by thermal ionization mass spectrometry.

    Science.gov (United States)

    Veličković, S R; Đustebek, J B; Veljković, F M; Veljković, M V

    2012-05-01

    Clusters of the type Li(n)X (X = halides) can be considered as potential building blocks of cluster-assembly materials. In this work, Li(n)Br (n = 2-7) clusters were obtained by a thermal ionization source of modified design and selected by a magnetic sector mass spectrometer. Positive ions of the Li(n)Br (n = 4-7) cluster were detected for the first time. The order of ion intensities was Li(2)Br(+) > Li(4)Br(+) > Li(5)Br(+) > Li(6)Br(+) > Li(3)Br(+). The ionization energies (IEs) were measured and found to be 3.95 ± 0.20 eV for Li(2)Br, 3.92 ± 0.20 eV for Li(3)Br, 3.93 ± 0.20 eV for Li(4)Br, 4.08 ± 0.20 eV for Li(5)Br, 4.14 ± 0.20 eV for Li(6)Br and 4.19 ± 0.20 eV for Li(7)Br. All of these clusters have a much lower ionization potential than that of the lithium atom, so they belong to the superalkali class. The IEs of Li(n)Br (n = 2-4) are slightly lower than those in the corresponding small Li(n) or Li(n)H clusters, whereas the IEs of Li(n)Br are very similar to those of Li(n) or Li(n)H for n = 5 and 6. The thermal ionization source of modified design is an important means for simultaneously obtaining and measuring the IEs of Li(n)Br (n = 2-7) clusters (because their ions are hermodynamically stable with respect to the loss of lithium atoms in the gas phase) and increasingly contributes toward the development of clusters for practical applications. Copyright © 2012 John Wiley & Sons, Ltd.

  16. The quantitative analysis of silicon carbide surface smoothing by Ar and Xe cluster ions

    Science.gov (United States)

    Ieshkin, A. E.; Kireev, D. S.; Ermakov, Yu. A.; Trifonov, A. S.; Presnov, D. E.; Garshev, A. V.; Anufriev, Yu. V.; Prokhorova, I. G.; Krupenin, V. A.; Chernysh, V. S.

    2018-04-01

    The gas cluster ion beam technique was used for the silicon carbide crystal surface smoothing. The effect of processing by two inert cluster ions, argon and xenon, was quantitatively compared. While argon is a standard element for GCIB, results for xenon clusters were not reported yet. Scanning probe microscopy and high resolution transmission electron microscopy techniques were used for the analysis of the surface roughness and surface crystal layer quality. The gas cluster ion beam processing results in surface relief smoothing down to average roughness about 1 nm for both elements. It was shown that xenon as the working gas is more effective: sputtering rate for xenon clusters is 2.5 times higher than for argon at the same beam energy. High resolution transmission electron microscopy analysis of the surface defect layer gives values of 7 ± 2 nm and 8 ± 2 nm for treatment with argon and xenon clusters.

  17. Temperature study of magnetic resonance spectra of co-modified (Co,N-TiO2 nanocomposites

    Directory of Open Access Journals (Sweden)

    Guskos Nikos

    2016-06-01

    Full Text Available The (nCo,N-TiO2 (n = 1, 5 and 10 wt.% of Co nanocomposites were investigated by magnetic resonance spectroscopy in 4 K to 290 K range. Analyses of ferromagnetic/electron paramagnetic resonance (FMR/EPR spectra in terms of four Callen lineshape components revealed the existence of two types of magnetic centers, one derived from metallic cobalt nanoparticles in superparamagnetic (SPM phase and the other from cobalt clusters in the TiO2 lattice. Additionally, at low temperature the EPR spectrum arising from Ti3+ ions was also registered. Both relaxations of the Landau-Lifshitz type and the Bloch-Bloembergen type played an important role at high temperature in determining the linewidths and the latter relaxation was prevailing at low temperature. Analysis of the integrated intensity showed that the SPM signal is due to small size FM cobalt nanoparticles while the paramagnetic signal from Co clusters originates from those nanoparticles in which the concentration of magnetic polarons is below the percolation threshold.

  18. Decontamination of Metal Ions in Soil by Supercritical CO2 Extraction with Crown Ether

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihe; Park, Kwangheon [Kyunghee University, Yongin (Korea, Republic of)

    2015-05-15

    Previous decontamination methods have shortcomings in that they produce additional waste due to the usage of solutions with chemical toxicity. Hence, demand is strong for new decontamination methods that can guarantee effective decontamination while decreasing the chemical solution. In particular, methods using supercritical CO2 as a means of decontamination are currently in progress. This study examines the method of decontaminating metallic ions inside soil using supercritical CO2. This paper examined the effects of extracting metallic ions inside soil using supercritical CO2 and crown ether as the ligand. It was confirmed that extraction effectiveness increases following greater usage of ligand and co-ligand, with a drastic increase in extraction effectiveness when using extracts over a certain dose. Moreover, it was shown that if the usage of ligand and additive decreases, the extraction ratio also decreases.

  19. Decontamination of Metal Ions in Soil by Supercritical CO2 Extraction with Crown Ether

    International Nuclear Information System (INIS)

    Park, Jihe; Park, Kwangheon

    2015-01-01

    Previous decontamination methods have shortcomings in that they produce additional waste due to the usage of solutions with chemical toxicity. Hence, demand is strong for new decontamination methods that can guarantee effective decontamination while decreasing the chemical solution. In particular, methods using supercritical CO2 as a means of decontamination are currently in progress. This study examines the method of decontaminating metallic ions inside soil using supercritical CO2. This paper examined the effects of extracting metallic ions inside soil using supercritical CO2 and crown ether as the ligand. It was confirmed that extraction effectiveness increases following greater usage of ligand and co-ligand, with a drastic increase in extraction effectiveness when using extracts over a certain dose. Moreover, it was shown that if the usage of ligand and additive decreases, the extraction ratio also decreases

  20. Size dependent hcp-to-fcc transition temperature in Co nanoclusters obtained by ion implantation in silica

    International Nuclear Information System (INIS)

    Mattei, G.; Maurizio, C.; Fernandez, C Julian de; Mazzoldi, P.; Battaglin, G.; Canton, P.; Cattaruzza, E.; Scian, C.

    2006-01-01

    In this work we present in situ investigations on the increase of the hcp-to-fcc transition temperature for Co with respect to the bulk value (420 deg. C) when nanoclusters are considered. Starting from Co:SiO 2 composites obtained by ion implantation with average Co cluster size of about 5 nm, a transition temperature between 800 deg. C and 900 deg. C is found upon thermal annealing in vacuum by in situ transmission electron microscopy. Preliminary results on electron irradiation to promote the transition at lower temperatures are presented

  1. Coherent scattering of CO2 light from ion-acoustic waves

    International Nuclear Information System (INIS)

    Peratt, A.L.; Watterson, R.L.; Derfler, H.

    1977-01-01

    Scattering of laser radiation from ion-acoustic waves in a plasma is investigated analytically and experimentally. The formulation predicts a coherent component of the scattered power on a largely incoherent background spectrum when the acoustic analog of Bragg's law and Doppler shift conditions are satisfied. The experiment consists of a hybrid CO 2 laser system capable of either low power continuous wave or high power pulsed mode operation. A heterodyne light mixing scheme is used to detect the scattered power. The proportionality predicted by the theory is verified by scattering from externally excited acoustic and ion-acoustic waves; continuous wave and pulsed modes in each case. Measurement of the ion-acoustic dispersion relation by continuous wave scattering is also presented

  2. Effect of Co2+ Ions Doping on the Structural and Optical Properties of Magnesium Aluminate

    Science.gov (United States)

    Kanwal, Kiran; Ismail, Bushra; Rajani, K. S.; Kissinger, N. J. Suthan; Zeb, Aurang

    2017-07-01

    Cobalt-doped nanosized magnesium aluminate (Mg1-xCoxAl2O4) samples having different compositions ( x = 0.2, 0.4, 0.6, 0.8, 1.0) were synthesized by a chemical co-precipitation method. All samples were characterized by means of x-ray diffraction (XRD), scanning electron microscopy, Fourier transform infrared spectroscopy, ultra violet-visible spectroscopy, photoluminescence and diffused reflectance spectroscopy. The results of XRD revealed that the samples were spinel single phase cubic close packed crystalline materials. The lattice constant and x-ray density were found to be affected by the ionic radii of the doped metal cations. Using the Debye-Scherrer formula, the calculated crystalline size was found to be Co2+ ion concentration-dependent and varied between 32 nm and 40 nm. Nano-dimensions and phase of the Mg1-xCoxAl2O4 samples were analyzed and the replacement of Mg2+ ions with Co2+ ions was confirmed by elemental analysis. Three strong absorption bands at 540 nm, 580 nm and 630 nm were observed for the doped samples which are attributed to the three spin-allowed 4T1g (4F) → 4T2g, 4A2g, 4T1g (4P) electronic transitions of Co2+ at tetrahedral lattice sites. Nanophosphors have optical properties different from bulk because of spatial confinement and non-radiative relaxation. Decreases in particle size can increase the surface area and the defects, which can in turn increase the luminescent efficiency to make it very useful for tunable laser operations, persistent phosphorescence, color centers, photoconductivity and luminescence for display technology. MgAl2O4 was doped with Co2+ ions using a co-precipitation method and the optical absorption studies revealed that there is a decrease of band gap due to the increase of Co2+ content. The emission intensity of this phosphor is observed at 449 nm with a sharp peak attributed to the smaller size of the particles and the homogeneity of the powder.

  3. Lifetime and quenching of CO /a super 3 pi/ produced by recombination of CO2 ions in a helium afterglow.

    Science.gov (United States)

    Wauchop, T. S.; Broida, H. P.

    1972-01-01

    Demonstration that rapid dissociative recombination of CO2(+) in a flowing, helium afterglow is an efficient source of CO in the a super 3 pi metastable state. Ions produced by mixing CO2 with He(2 super 3 S) recombine to produce a CO metastable afterglow with a number density as great as 10 to the 9th per sq cm. Monitoring of the (a super 3 pi-X super 1 sigma) Cameron transition in CO was used to study the lifetime and quenching of CO (a super 3 pi) by CO2, N2, NO, and He. Recombination of CO2(+) also produces CO in the d super 3 delta and a' super 3 sigma states.

  4. Low temperature EPR investigation of Co{sup 2+} ion doped into rutile TiO{sub 2} single crystal: Experiments and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zerentürk, A. [Department of Physics, Marmara University, 34722 Kadıköy, Istanbul (Turkey); Açıkgöz, M., E-mail: muhammed.acikgoz@eng.bau.edu.tr [Bahcesehir University, Faculty of Engineering and Natural Sciences, Besiktas Campus, 34349 Besiktas, Istanbul (Turkey); Kazan, S.; Yıldız, F.; Aktaş, B. [Department of Physics, Gebze Technical University, 41400 Gebze, Kocaeli (Turkey)

    2017-02-01

    In this paper, we present the results of X-band EPR spectra of Co{sup 2+} ion doped rutile (TiO{sub 2}) which is one of the most promising memristor material. We obtained the angular variation of spectra in three mutually perpendicular planes at liquid helium (7–13 K) temperatures. Since the impurity ions have ½ effective spin and 7/2 nuclear spin, a relatively simple spin Hamiltonian containing only electronic Zeeman and hyperfine terms was utilized. Two different methods were used in theoretical analysis. Firstly, a linear regression analysis of spectra based on perturbation theory was studied. However, this approach is not sufficient for analyzing Co{sup +2} spectra and leads to complex eigenvectors for G and A tensors due to large anisotropy of eigenvalues. Therefore, all spectra were analyzed again with exact diagonalization of spin Hamiltonian and the high accuracy eigenvalues and eigenvectors of G and A tensors were obtained by taking into account the effect of small sample misalignment from the exact crystallographic planes due to experimental conditions. Our results show that eigen-axes of g and A tensors are parallel to crystallographic directions. Hence, our EPR experiments proves that Co{sup 2+} ions substitute for Ti{sup 4+} ions in lattice. The obtained principal values of g tensor are g{sub x}=2.110(6), g{sub y}=5.890(2), g{sub z}=3.725(7) and principal values of hyperfine tensor are A{sub x}=42.4, A{sub y}=152.7, A{sub z}=26 (in 10{sup −4}/cm). - Highlights: • X-band EPR spectra of Co{sup 2+} ion doped rutile (TiO{sub 2}) investigated at 7–13 K. • Two different methods were used in theoretical analysis. • The presence of two structurally equivalent centers for Co{sup 2+} ions observed. • It is concluded that impurity ions substitute for Ti{sup 4+} ion.

  5. A dual cryogenic ion trap spectrometer for the formation and characterization of solvated ionic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, Brett M.; Voss, Jonathan M.; Garand, Etienne, E-mail: egarand@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706 (United States)

    2015-11-28

    A new experimental approach is presented in which two separate cryogenic ion traps are used to reproducibly form weakly bound solvent clusters around electrosprayed ions and messenger-tag them for single-photon infrared photodissociation spectroscopy. This approach thus enables the vibrational characterization of ionic clusters comprised of a solvent network around large and non-volatile ions. We demonstrate the capabilities of the instrument by clustering water, methanol, and acetone around a protonated glycylglycine peptide. For water, cluster sizes with greater than twenty solvent molecules around a single ion are readily formed. We further demonstrate that similar water clusters can be formed around ions having a shielded charge center or those that do not readily form hydrogen bonds. Finally, infrared photodissociation spectra of D{sub 2}-tagged GlyGlyH{sup +} ⋅ (H{sub 2}O){sub 1−4} are presented. They display well-resolved spectral features and comparisons with calculations reveal detailed information on the solvation structures of this prototypical peptide.

  6. Eu/Tb ions co-doped white light luminescence Y2O3 phosphors

    International Nuclear Information System (INIS)

    Tu Dong; Liang Yujun; Liu Rong; Li Daoyi

    2011-01-01

    Y 2 O 3 :Eu 3+ , Tb 3+ phosphors with white emission are prepared with different doping concentration of Eu 3+ and Tb 3+ ions and synthesizing temperatures from 750 to 950 deg. C by the co-precipitation method. The resulted phosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The results of XRD indicate that the crystallinity of the synthesized samples increases with enhancing the firing temperature. The photoluminescence spectra indicate the Eu 3+ and Tb 3+ co-doped Y 2 O 3 phosphors show five main emission peaks: three at 590, 611 and 629 nm originate from Eu 3+ and two at 481 and 541 nm originate from Tb 3+ , under excitation of 250-320 nm irradition. The white light luminescence color could be changed by varying the excitation wavelength. Different concentrations of Eu 3+ and Tb 3+ ions were induced into the Y 2 O 3 lattice and the energy transfer from Tb 3+ →Eu 3+ ions in these phosphors was found. The Commission International de l'Eclairage (CIE) chromaticity shows that the Y 2 O 3 :Eu 3+ , Tb 3+ phosphors can obtain an intense white emission. - Highlights: → Novel phosphors Y 2 O 3 :Eu 3+ , Tb 3+ have been synthesized by co-precipitation method. → Samples emit white light with excellent color coordinates under UV excitation. → Luminescence color could be changed by varying the excitation wavelength. → Energy transfer from Tb 3+ →Eu 3+ ions in these phosphors was found.

  7. Synthesis and Characterization of Rh-Co Butterfly Clusters Capped by Functionally Substituted 1-Alkynes

    Institute of Scientific and Technical Information of China (English)

    朱保华; 胡斌; 张伟强; 边治国; 赵全义; 殷元骐; 孙杰

    2003-01-01

    By the reactions of [Rh2Co2(CO)12] 1 with functionally substituted alkyne ligands HC≡CR 2 (R = FeCp2) and 3 (R = 2-OH-C6H4COOCH2), respectively in n-hexane at room temperature, two new cluster derivatives [Rh2Co2(CO)6(μ-CO)4(μ4, η2-HC≡CR)] 4 (R = FeCp2) and 5 (R = 2-OH-C6H4COOCH2) were obtained respectively. The alkyne was inserted into the Co-Co bond of cluster 1 to give two butterfly clusters. Cluster 4 has been determined by single-crystal X-ray diffraction. Crystallographic data: C22H10Co2FeO10Rh2, Mr = 813.83, orthorhombic, space group P212121, a = 11.5318(7), b = 12.6572(7), c = 17.018(1) A。, V = 2483.9(3) A。3, Z = 4, Dc = 2.176 g/cm3, F(000) = 1568, μ = 3.233 mm-1, the final R = 0.0366 and wR = 0.0899 for 5367 observed reflections with I > 2σ(I). The two clusters have also been characterized by elemental analysis, IR and 1H-NMR spectroscopy.

  8. Formation and metastable decomposition of unprotonated ammonia cluster ions upon femtosecond ionization

    International Nuclear Information System (INIS)

    Buzza, S.A.; Wei, S.; Purnell, J.; Castleman, A.W. Jr.

    1995-01-01

    The formation and metastable dissociation mechanism of unprotonated ammonia cluster ions, (NH 3 ) + n , produced by multiphoton ionization (MPI) at 624 nm and a nominal pulse width of 350 fs, are investigated through a reflectron time-of-flight (TOF) mass spectrometric technique. Detection of the unprotonated ions after femtosecond and nanosecond multiphoton ionization under various intensity conditions is explained. The role of the energy of the ionizing photons, and the observation of these ions after femtosecond MPI is examined. The formation of the unprotonated series is found to be a function of intensity in the case of ionization on the nanosecond time scale, but not so for the femtosecond time domain. The results can be explained in terms of ionization mechanisms and ionizing pulse durations. The findings of the present study suggest that the unprotonated ions are trapped behind the barrier to intracluster proton transfer and/or concomitant NH 2 loss. The studies of metastable decomposition also reveal that the unprotonated ammonia cluster ions dissociate in the field-free region of the TOF by losing an NH 2 radical rather than via the evaporative loss of NH 3 as occurs for protonated clusters. Additionally, isotopic investigations of the unimolecular decay reveal a strong dependence on the conditions of cluster formation. The cluster formation condition dependence of the unimolecular decay is further investigated by altering formation temperatures and observing the consequences reflected by changes in the spontaneous metastable decay rate constant. This is a unique example of a cluster system whose metastable dissociation does not obey an evaporative ensemble model

  9. Gas-phase fragmentation of coordination compounds: loss of CO(2) from inorganic carbonato complexes to give metal oxide ions

    Science.gov (United States)

    Dalgaard; McKenzie

    1999-10-01

    Using electrospray ionization mass spectrometry, novel transition metal oxide coordination complex ions are proposed as the products of the collision-induced dissociation (CID) of some carbonato complex ions through the loss of a mass equivalent to CO(2). CID spectra of [(tpa)CoCO(3)](+) (tpa = tris(2-pyridylmethyl)methylamine), [(bispicMe(2)en)Fe(&mgr;-O)(&mgr;-CO(3))Fe(bispicMe(2)en)]2+ (bispicMe(2)en = N,N'-dimethyl-N,N'-bis(2-pyridylmethy)eth- ane-1, 2-diamine) and [(bpbp)Cu(2)CO(3)](+) (bpbp(-) = bis[(bis-(2-pyridylmethyl)amino)methyl]-4-tertbutylpheno-lato(1-)), show peaks assigned to the mono- and dinuclear oxide cations, [(tpa)CoO](+), [(bispicMe(2)en)(2)Fe(2)(O)(2)]2+ and [(bpbp)Cu(2)O](+), as the dominant species. These results can be likened to the reverse of typical synthetic reactions in which metal hydroxide compounds react with CO(2) to give metal carbonato compounds. Because of the lack of available protons in the gas phase, novel oxide species rather than the more common hydroxide ions are generated. These oxide ions are relevant to the highly oxidizing species proposed in oxygenation reactions catalysed by metal oxides and metalloenzymes. Copyright 1999 John Wiley & Sons, Ltd.

  10. Cluster ion-surface interactions: from meV to MeV energies

    Energy Technology Data Exchange (ETDEWEB)

    Nordlund, Kai; Meinander, Kristoffer; Jaervi, Tommi T.; Peltola, Jarkko; Samela, Juha [Accelerator Laboratory, University of Helsinki (Finland)

    2008-07-01

    The nature of cluster ion-surface interactions changes dramatically with the kinetic energy of the incoming cluster species. In this talk I review some of our recent work on the nature of cluster-surface interactions spanning an energy range from a few MeV/cluster to about 1 MeV/cluster and cluster sizes in the range of 10 - 1000 atoms/cluster. In the energy range of a few MeV/cluster ion, the kinetic energy of the incoming ion is insignificant compared to the energy gained when the surface potential energy at the cluster-surface interface is released and partly translated into kinetic energy. Even in this energy regime I show that surprisingly drastic effects can occur. When the energy of the incoming cluster is raised to a few eV/atom, the kinetic energy of the incoming cluster starts to affect the deposition. It will cause the cluster to entirely reform on impact. When the energy is raised to the range of keV's/cluster, the clusters start to penetrate the sample, fairly similar to conventional ion implantation. However, in dense targets the cluster ions may stick close to each other long enough to cause a significant enhancement of the heat spike in the material. Finally, I show that at kinetic energies around 1 MeV/cluster the cluster enhancement of the heat spike may lead to dramatic surface effects.

  11. Ion clusters, REB, and current sheath characteristics in focused discharges

    International Nuclear Information System (INIS)

    Bortolotti, A.; Brzosko, J.; DeChiara, P.; Kilic, H.; Mezzetti, F.; Nardi, V.; Powell, C.; Zeng, D.

    1990-01-01

    Small fluctuations in the current sheath characteristics (peak current density, FWHM of leading sheath, control parameters of sheath internal structure) are linked to wide fluctuations of ion and ion cluster emission from the pinch. Magnetic probe data are used for correlating variations of current sheath parameters with particle emission intensity, Z/M composition, particle energy spectrum. The emission of ion and ion clusters at 90 degrees from the axis of a plasma focus discharge is monitored simultaneously with the 0 degrees emission. The particle energy spectrum is analyzed with a Thomson (parabola) spectrometer (time resolution ∼ 1 nanosec). The cross-sectional structure of the REB at 180 degrees along the discharge axis is monitored via the deposition of collective-field accelerated ions on a target in the REB direction. Etched tracks of ion and ion clusters are in all cases recorded on CR-39 plates. Sharp peaks of the D + -ion spectrum at 90 degrees are found for E > 200 keV/unit charge in all focused discharges. These peaks are due to ion crossing of the azimuthal magnetic field of the pinch region, in a predominant ion cluster structure

  12. Layered double hydroxides for preparing CoMn_2O_4 nanoparticles as anodes of lithium ion batteries

    International Nuclear Information System (INIS)

    Pan, Xu; Ma, Jingjing; Yuan, Ruo; Yang, Xia

    2017-01-01

    In the field of lithium-ion batteries, CoMn_2O_4 as an anode material has attracted a wide attention because it inherited the splendid electrochemical performances of Mn and Co-based metal oxides. Compared to graphite, Co-based oxides have a higher capacity which is about twice of the graphite. Moreover, Mn-based oxides have lower operating voltages and manganese exists abundantly in nature. Layered double hydroxides (LDHs), similar with brucite structure, were used as precursor for CoMn_2O_4 nanoparticles in this work. Under high temperature process, the LDHs decomposed to CoMn_2O_4 nanoparticles. When evaluated as anode materials for lithium ion batteries, the CoMn_2O_4 nanoparticles behaved good electrochemical performance with the discharge and charge capacity of 733 mAh g"-"1 and 721 mAh g"-"1 at current density of 200 mA g"-"1 after 100 cycles. This method for preparing CoMn_2O_4 nanoparticles is easy, which may provide a way for synthesis of other bimetallic oxides and anodes of lithium ion batteries. - Highlights: • Layered double hydroxides were employed as precursors to synthesize CoMn_2O_4. • The CoMn_2O_4 nanoparticles behaved good electrochemical performance. • This study provides a guideline for preparing bimetallic oxides.

  13. Co-clustering for Weblogs in Semantic Space

    DEFF Research Database (Denmark)

    Zong, Yu; Xu, Guandong; Dolog, Peter

    2010-01-01

    Web clustering is an approach for aggregating web objects into various groups according to underlying relationships among them. Finding co-clusters of web objects in semantic space is an interesting topic in the context of web usage mining, which is able to capture the underlying user navigational...... interest and content preference simultaneously. In this paper we will present a novel web co-clustering algorithm named Co-Clustering in Semantic space (COCS) to simultaneously partition web users and pages via a latent semantic analysis approach. In COCS, we first, train the latent semantic space...... of weblog data by using Probabilistic Latent Semantic Analysis (PLSA) model, and then, project all weblog data objects into this semantic space with probability distribution to capture the relationship among web pages and web users, at last, propose a clustering algorithm to generate the co...

  14. Investigation of the alpha cluster model and the density matrix expansion in ion-ion collision

    International Nuclear Information System (INIS)

    Rashdan, M.B.M.

    1986-01-01

    This thesis deals with the investigation of the alpha cluster model (ACM) of brink and studies of the accuracy of the density matrix expansion (DME) approximation in deriving the real part of the ion-ion optical potential. the ACM is applied to calculate the inelastic 0 1 + →2 1 + charge form factor for electron scattering by 12 C to investigate the validity of this model for 12 C nucleus. it is found that the experimental curve can be fitted over the entire range of the momentum transfer by a generator - coordinate state for the 2 1 + state that consist of a superposition of two triangular ACM states with two different cluster separations and the same oscillator parameter

  15. Thermal responsive ion selectivity of uranyl peroxide nanocages: an inorganic mimic of K{sup +} ion channels

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yunyi; Sun, Xinyu; Liu, Tianbo [Department of Polymer Science, University of Akron, Akron, OH (United States); Szymanowski, Jennifer E.S.; Burns, Peter C. [Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN (United States)

    2016-06-06

    An actinyl peroxide cage cluster, Li{sub 48+m}K{sub 12}(OH){sub m}[UO{sub 2}(O{sub 2})(OH)]{sub 60} (H{sub 2}O){sub n} (m∼20 and n∼310; U{sub 60}), discriminates precisely between Na{sup +} and K{sup +} ions when heated to certain temperatures, a most essential feature for K{sup +} selective filters. The U{sub 60} clusters demonstrate several other features in common with K{sup +} ion channels, including passive transport of K{sup +} ions, a high flux rate, and the dehydration of U{sub 60} and K{sup +} ions. These qualities make U{sub 60} (a pure inorganic cluster) a promising ion channel mimic in an aqueous environment. Laser light scattering (LLS) and isothermal titration calorimetry (ITC) studies revealed that the tailorable ion selectivity of U{sub 60} clusters is a result of the thermal responsiveness of the U{sub 60} hydration shells. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. In situ tetrazole templated chair-like decanuclear azido-cobalt(II) SMM containing both tetra- and octa-hedral Co(II) ions.

    Science.gov (United States)

    Zhang, Yuan-Zhu; Gao, Song; Sato, Osamu

    2015-01-14

    An azido-bridged chair-like decanuclear cluster: [Co(II)10(bzp)8(Metz)2(N3)18]·4MeOH·3H2O (1, bzp = 2-benzoylpyridine and HMetz = 5-methyl-1H-tetrazole) was prepared with in situ tetrazolate anions as templates in a sealed system. 1 containing both octahedral and tetrahedral Co(II) ions exhibited slow relaxation of magnetization with an effective barrier of 26 K under an applied dc field of 1 kOe.

  17. A {sup 13}CO Detection in a Brightest Cluster Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Vantyghem, A. N.; McNamara, B. R.; Hogan, M. T. [Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Edge, A. C. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Combes, F.; Salomé, P. [LERMA, Observatoire de Paris, CNRS, UPMC, PSL Univ., 61 avenue de l’Observatoire, F-75014 Paris (France); Russell, H. R.; Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); McDonald, M. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Nulsen, P. E. J., E-mail: a2vantyg@uwaterloo.ca [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2017-10-20

    We present ALMA Cycle 4 observations of CO(1-0), CO(3-2), and {sup 13}CO(3-2) line emission in the brightest cluster galaxy (BCG) of RXJ0821+0752. This is one of the first detections of {sup 13}CO line emission in a galaxy cluster. Half of the CO(3-2) line emission originates from two clumps of molecular gas that are spatially offset from the galactic center. These clumps are surrounded by diffuse emission that extends 8 kpc in length. The detected {sup 13}CO emission is confined entirely to the two bright clumps, with any emission outside of this region lying below our detection threshold. Two distinct velocity components with similar integrated fluxes are detected in the {sup 12}CO spectra. The narrower component (60 km s{sup −1} FWHM) is consistent in both velocity centroid and linewidth with {sup 13}CO(3-2) emission, while the broader (130–160 km s{sup −1}), slightly blueshifted wing has no associated {sup 13}CO(3-2) emission. A simple local thermodynamic model indicates that the {sup 13}CO emission traces 2.1 × 10{sup 9} M {sub ⊙} of molecular gas. Isolating the {sup 12}CO velocity component that accompanies the {sup 13}CO emission yields a CO-to-H{sub 2} conversion factor of α {sub CO} = 2.3 M {sub ⊙} (K km s{sup −1}){sup −1}, which is a factor of two lower than the Galactic value. Adopting the Galactic CO-to-H{sub 2} conversion factor in BCGs may therefore overestimate their molecular gas masses by a factor of two. This is within the object-to-object scatter from extragalactic sources, so calibrations in a larger sample of clusters are necessary in order to confirm a sub-Galactic conversion factor.

  18. Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO2 transformation

    Science.gov (United States)

    Shanmugam, Ramasamy; Thamaraichelvan, Arunachalam; Ganesan, Tharumeya Kuppusamy; Viswanathan, Balasubramanian

    2017-02-01

    Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO2 to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO2 to CO at an applied potential of -0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO2 to various value added chemicals.

  19. Properties of ammonium ion-water clusters: analyses of structure evolution, noncovalent interactions, and temperature and humidity effects.

    Science.gov (United States)

    Pei, Shi-Tu; Jiang, Shuai; Liu, Yi-Rong; Huang, Teng; Xu, Kang-Ming; Wen, Hui; Zhu, Yu-Peng; Huang, Wei

    2015-03-26

    Although ammonium ion-water clusters are abundant in the biosphere, some information regarding these clusters, such as their growth route, the influence of temperature and humidity, and the concentrations of various hydrated clusters, is lacking. In this study, theoretical calculations are performed on ammonium ion-water clusters. These theoretical calculations are focused on determining the following characteristics: (1) the pattern of cluster growth; (2) the percentages of clusters of the same size at different temperatures and humidities; (3) the distributions of different isomers for the same size clusters at different temperatures; (4) the relative strengths of the noncovalent interactions for clusters of different sizes. The results suggest that the dipole moment may be very significant for the ammonium ion-water system, and some new stable isomers were found. The nucleation of ammonium ions and water molecules is favorable at low temperatures; thus, the clusters observed at high altitudes might not be present at low altitudes. High humidity can contribute to the formation of large ammonium ion-water clusters, whereas the formation of small clusters may be favorable under low-humidity conditions. The potential energy surfaces (PES) of these different sized clusters are complicated and differ according to the distribution of isomers at different temperatures. Some similar structures are observed between NH4(+)(H2O)n and M(H2O)n (where M represents an alkali metal ion or water molecule); when n = 8, the clusters begin to form the closed-cage geometry. As the cluster size increases, these interactions become progressively weaker. The successive binding energy at the DF-MP2-F12/VDZ-F12 level is better than that at the PW91PW91/6-311++G(3df, 3pd) level and is consistent with the experimentally determined values.

  20. Investigation of Thermal Stability of P2-NaxCoO2 Cathode Materials for Sodium Ion Batteries Using Real-Time Electron Microscopy.

    Science.gov (United States)

    Hwang, Sooyeon; Lee, Yongho; Jo, Eunmi; Chung, Kyung Yoon; Choi, Wonchang; Kim, Seung Min; Chang, Wonyoung

    2017-06-07

    Here, we take advantage of in situ transmission electron microscopy (TEM) to investigate the thermal stability of P2-type Na x CoO 2 cathode materials for sodium ion batteries, which are promising candidates for next-generation lithium ion batteries. A double-tilt TEM heating holder was used to directly characterize the changes in the morphology and the crystallographic and electronic structures of the materials with increase in temperature. The electron diffraction patterns and the electron energy loss spectra demonstrated the presence of cobalt oxides (Co 3 O 4 , CoO) and even metallic cobalt (Co) at higher temperatures as a result of reduction of Co ions and loss of oxygen. The bright-field TEM images revealed that the surface of Na x CoO 2 becomes porous at high temperatures. Higher cutoff voltages result in degrading thermal stability of Na x CoO 2 . The observations herein provide a valuable insight that thermal stability is one of the important factors to be considered in addition to the electrochemical properties when developing new electrode materials for novel battery systems.

  1. Spin-canting magnetization in an unusual Co4 cluster-based layer compound from a 2,3-dihydroxyquinoxaline ligand.

    Science.gov (United States)

    Yang, Chen-I; Chuang, Po-Hsiang; Lee, Gene-Hsiang; Peng, Shie-Ming; Lu, Kuang-Lieh

    2012-01-16

    The self-assembly of Co(O(2)CPh)(2) with a 2,3-dihydroxyquinoxaline (H(2)dhq) linker has revealed a new two-dimensional cluster-based compound, [Co(4)(OMe)(2)(O(2)CPh)(2)(dhq)(2)(MeOH)(2)](n), which shows spin-canted magnetization and a definite magnetic hysteresis loop.

  2. From molecular clusters to nanoparticles: second-generation ion-mediated nucleation model

    Directory of Open Access Journals (Sweden)

    F. Yu

    2006-01-01

    Full Text Available Ions, which are generated in the atmosphere by galactic cosmic rays and other ionization sources, may play an important role in the formation of atmospheric aerosols. In the paper, a new second-generation ion-mediated nucleation (IMN model is presented. The new model explicitly treats the evaporation of neutral and charged clusters and it describes the evolution of the size spectra and composition of both charged and neutral clusters/particles ranging from small clusters of few molecules to large particles of several micrometers in diameter. Schemes used to calculate the evaporation coefficients for small neutral and charged clusters are consistent with the experimental data within the uncertainty range. The present IMN model, which is size-, composition-, and type-resolved, is a powerful tool for investigating the dominant mechanisms and key parameters controlling the formation and subsequent growth of nanoparticles in the atmosphere. This model can be used to analyze simultaneous measurements of the ion-mobility spectra and particle size distributions, which became available only recently. General features of the spectra for ions smaller than the critical size, size-dependent fractions of charged nanoparticles, and asymmetrical charging of freshly nucleated particles predicted by the new IMN model are consistent with recent measurements. Results obtained using the second generation IMN model, in which the most recent thermodynamic data for neutral and charged H2SO4-H2O clusters were used, suggest that ion-mediated nucleation of H2SO4-H2O can lead to a significant production of new particles in the lower atmosphere (including the boundary layer under favorable conditions. It has been shown that freshly nucleated particles of few nanometers in size can grow by the condensation of low volatile organic compounds to the size of cloud condensation nuclei. In such cases, the chemical composition of nucleated particles larger than ~10 nm is dominated

  3. Enhancing visible light photocatalytic and photocharge separation of (BiO)_2CO_3 plate via dramatic I"− ions doping effect

    International Nuclear Information System (INIS)

    Liang, Lei; Cao, Jing; Lin, Haili; Guo, Xiaomin; Zhang, Meiyu; Chen, Shifu

    2016-01-01

    Highlights: • Novel I-(BiO)_2CO_3 was prepared by a facile chemical precipitation method. • I"− ions impurity level located on the top of valence band of (BiO)_2CO_3. • I"− ions doping largely improved photocatalytic activity of I-(BiO)_2CO_3. • I-(BiO)_2CO_3 displayed excellent photocharge separation efficiency. - Abstract: Novel I"− ions doped (BiO)_2CO_3 (I-(BiO)_2CO_3) photocatalysts were successfully synthesized via a facile chemical precipitation method. Under visible light (λ > 400 nm), I-(BiO)_2CO_3 displayed much higher activity for rhodamine B and dichlorophenol degradation than the undoped (BiO)_2CO_3. The pseudo-first-order rate constant k_a_p_p of RhB degradation over 15.0% I-(BiO)_2CO_3 was 0.54 h"−"1, which is 11.3 times higher than that of (BiO)_2CO_3. The doped I"− ions formed an impurity level on the top of valence band of (BiO)_2CO_3 and induced much more visible light to be absorbed. The enhanced photocurrent and surface photovoltage properties were detected, which strongly ensures the efficient separation of electrons and holes in I-(BiO)_2CO_3 system under visible light. It provides a facile way to improve the photocatalytic activity of the wide-band-gap (BiO)_2CO_3 via intense doping effect of I"− ions.

  4. Heavy-ion dominance near Cluster perigees

    Science.gov (United States)

    Ferradas, C. P.; Zhang, J.-C.; Kistler, L. M.; Spence, H. E.

    2015-12-01

    Time periods in which heavy ions dominate over H+ in the energy range of 1-40 keV were observed by the Cluster Ion Spectrometry (CIS)/COmposition DIstribution Function (CODIF) instrument onboard Cluster Spacecraft 4 at L values less than 4. The characteristic feature is a narrow flux peak at around 10 keV that extends into low L values, with He+ and/or O+ dominating. In the present work we perform a statistical study of these events and examine their temporal occurrence and spatial distribution. The observed features, both the narrow energy range and the heavy-ion dominance, can be interpreted using a model of ion drift from the plasma sheet, subject to charge exchange losses. The narrow energy range corresponds to the only energy range that has direct drift access from the plasma sheet during quiet times. The drift time to these locations from the plasma sheet is > 30 h, so that charge exchange has a significant impact on the population. We show that a simple drift/loss model can explain the dependence on L shell and MLT of these heavy-ion-dominant time periods.

  5. Magnetic and dielectric properties of alkaline earth Ca2+ and Ba2+ ions co-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Yang, C.; Liu, C.Z.; Wang, C.M.; Zhang, W.G.; Jiang, J.S.

    2012-01-01

    Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles, Bi 0.8 Ca 0.2−x Ba x FeO 3 (x=0–0.20), were prepared by a sol–gel method. The phase structure, grain size, dielectric and magnetic properties of the prepared samples were investigated. The results showed that the lattice structure of the nanoparticles transformed from rhombohedral (x=0) to orthorhombic (x=0.07–0.19) and then to tetragonal (x=0.20) with x increased. The dielectric properties of the nanoparticles were affected by the properties of the substitutional ions as well as the crystalline structure of the samples. The magnetic properties of the nanoparticles were greatly improved and the T N of the nanoparticles was obviously increased. All the Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles presented the high ratio of M r /M from 0.527 to 0.571 and large coercivity from 4.335 to 5.163 KOe. - Highlights: ► Ca 2+ and Ba 2+ ions co-doped BiFeO 3 nanoparticles were prepared using a sol–gel method. ► The magnetic properties of the nanoparticles are greatly improved. ► The Neel temperature (T N ) of the nanoparticles is greatly increased. ► Doped ions and crystal structure affect the dielectric properties of the nanoparticles.

  6. Synthesis, Characterizations, and Applications of Metal-Ions Incorporated High Quality MCM-41 Catalysts

    International Nuclear Information System (INIS)

    Lim, Steven S.; Haller, Gary L.

    2013-01-01

    Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically V 5+ , Co 2+ , and Ni 2+ -incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated

  7. Photocatalytic properties of Co{sub 3}O{sub 4}/LiCoO{sub 2} recycled from spent lithium-ion batteries using citric acid as leaching agent

    Energy Technology Data Exchange (ETDEWEB)

    Santana, I.L.; Moreira, T.F.M.; Lelis, M.F.F.; Freitas, M.B.J.G., E-mail: marcosbjg@gmail.com

    2017-04-01

    In this work, cobalt and lithium from the cathodes of spent lithium-ion batteries were recycled to synthesize a mixture of Co{sub 3}O{sub 4} and LiCoO{sub 2}. The positive electrode was leached with citric acid in the green recycling. After being heated to 85 °C, the leaching solution formed a pink sol, and after being dried at 120 °C for 24 h, it formed a gel, which is a precursor material for Co{sub 3}O{sub 4} and LiCoO{sub 2} synthesis. A mixture of Co{sub 3}O{sub 4} and LT-LiCoO{sub 2} was obtained after the calcination of the precursor material at 450 °C for 3 h. The photocatalytic properties of the Co{sub 3}O{sub 4} and LiCoO{sub 2} were tested in the discoloration of methylene blue dye. The discoloration efficiency of methylene blue dye in the presence of Co{sub 3}O{sub 4} and LiCoO{sub 2} was 90% after 10 h and 100% after 24 h of heterogeneous catalysis. The contribution of this work is that it presents a means to produce valuable materials with photocatalytic properties from recycled batteries through a spent Li-ion battery recycling process without polluting the environment. - Highlights: • Synthesis a mixture of Co{sub 3}O{sub 4}/LiCoO{sub 2} from spent Li-ion batteries. • Citric acid for leaching of the cathodes of the spent Li-ion batteries. • Co{sub 3}O{sub 4}/LiCoO{sub 2} as catalysts in the photodegradation of the methylene blue dye.

  8. Transmitted ion energy loss distributions to detect cluster formation in silicon

    International Nuclear Information System (INIS)

    Selen, L.J.M.; Loon, A. van; IJzendoorn, L.J. van; Voigt, M.J.A. de

    2002-01-01

    The energy loss distribution of ions transmitted through a 5.7±0.2 μm thick Si crystal was measured and simulated with the Monte Carlo channeling simulation code FLUX. A general resemblance between the measured and simulated energy loss distributions was obtained after incorporation of an energy dependent energy loss in the simulation program. The energy loss calculations are used to investigate the feasibility to detect the presence of light element dopant clusters in a host crystal from the shape of the energy loss distribution, with transmission ion channeling. A curved crystal structure is used as a model for a region in the host crystal with clusters. The presence of the curvature does have a large influence on the transmitted energy distribution, which offers the possibility to determine the presence of dopant clusters in a host crystal with transmission ion channeling

  9. An ion-neutral model to investigate chemical ionization mass spectrometry analysis of atmospheric molecules - application to a mixed reagent ion system for hydroperoxides and organic acids

    Science.gov (United States)

    Heikes, Brian G.; Treadaway, Victoria; McNeill, Ashley S.; Silwal, Indira K. C.; O'Sullivan, Daniel W.

    2018-04-01

    An ion-neutral chemical kinetic model is described and used to simulate the negative ion chemistry occurring within a mixed-reagent ion chemical ionization mass spectrometer (CIMS). The model objective was the establishment of a theoretical basis to understand ambient pressure (variable sample flow and reagent ion carrier gas flow rates), water vapor, ozone and oxides of nitrogen effects on ion cluster sensitivities for hydrogen peroxide (H2O2), methyl peroxide (CH3OOH), formic acid (HFo) and acetic acid (HAc). The model development started with established atmospheric ion chemistry mechanisms, thermodynamic data and reaction rate coefficients. The chemical mechanism was augmented with additional reactions and their reaction rate coefficients specific to the analytes. Some existing reaction rate coefficients were modified to enable the model to match laboratory and field campaign determinations of ion cluster sensitivities as functions of CIMS sample flow rate and ambient humidity. Relative trends in predicted and observed sensitivities are compared as instrument specific factors preclude a direct calculation of instrument sensitivity as a function of sample pressure and humidity. Predicted sensitivity trends and experimental sensitivity trends suggested the model captured the reagent ion and cluster chemistry and reproduced trends in ion cluster sensitivity with sample flow and humidity observed with a CIMS instrument developed for atmospheric peroxide measurements (PCIMSs). The model was further used to investigate the potential for isobaric compounds as interferences in the measurement of the above species. For ambient O3 mixing ratios more than 50 times those of H2O2, O3-(H2O) was predicted to be a significant isobaric interference to the measurement of H2O2 using O2-(H2O2) at m/z 66. O3 and NO give rise to species and cluster ions, CO3-(H2O) and NO3-(H2O), respectively, which interfere in the measurement of CH3OOH using O2-(CH3OOH) at m/z 80. The CO3-(H2O

  10. Interaction of multicharged ions with molecules (CO2, C60) by coincident electron spectroscopy

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.

    2001-01-01

    First results for the investigation of electron capture processes in collisions between multicharged ions and molecule targets using electron spectroscopy in coincidence with charged fragments, are presented. It is shown that a much more detailed investigation of the capture reaction can be achieved using molecular instead of heavy atomic targets provided that an analysis of the target dissociation is made. The collisional systems 18 O 8+ +Ar, CO 2 and C 60 have been studied at 80 keV. Non coincident electron spectra as well as first results of double or triple coincidence experiments are discussed. Kinetic energy distributions of the C n + fragments (n=1 to 8) produced in multiple capture processes from C 60 target are given. A detailed investigation of the double capture process with CO 2 molecule allows the measurement of kinetic energy release distributions (KERD) which characterize the dissociation of CO 2 2+ molecular ions; our results are found to be very similar to those measured in double photoionisation experiments. (orig.)

  11. Adsorption Isotherms of Cs+, Co2+, Zn2+ and Eu3+ on Zirconium Vanadate Ion-Exchanger

    International Nuclear Information System (INIS)

    Shady, S.A.; El-Ashery, S.M.; El-Naggar, I.M.

    2009-01-01

    Zirconium vanadate had been prepared by the dropwise addition of 0.1 M sodium vanadate and 0.1 M zirconyl chloride by molar ratio of zirconium/vanadium 2. Exchange isotherms for Cs + /H + , Co 2+ /H + ,Zn 2+ /H + and Eu 3+ /H + have been determined at 25, 40 and 60 degree C. Besides, it was proved that cesium, cobalt, zinc and europium are chemically adsorbed. Moreover, the heat of adsorption of these ions on zirconium vanadate had been calculated and indicated that zirconium vanadate is of endothermic behavior towards these ions

  12. Functionalized graphene oxide quantum dot-PVA hydrogel: a colorimetric sensor for Fe2+, Co2+ and Cu2+ ions

    Science.gov (United States)

    Baruah, Upama; Chowdhury, Devasish

    2016-04-01

    Functionalized graphene oxide quantum dots (GOQDs)-poly(vinyl alcohol) (PVA) hybrid hydrogels were prepared using a simple, facile and cost-effective strategy. GOQDs bearing different surface functional groups were introduced as the cross-linking agent into the PVA matrix thereby resulting in gelation. The four different types of hybrid hydrogels were prepared using graphene oxide, reduced graphene oxide, ester functionalized graphene oxide and amine functionalized GOQDs as cross-linking agents. It was observed that the hybrid hydrogel prepared with amine functionalized GOQDs was the most stable. The potential applicability of using this solid sensing platform has been subsequently explored in an easy, simple, effective and sensitive method for optical detection of M2+ (Fe2+, Co2+ and Cu2+) in aqueous media involving colorimetric detection. Amine functionalized GOQDs-PVA hybrid hydrogel when put into the corresponding solution of Fe2+, Co2+ and Cu2+ renders brown, orange and blue coloration respectively of the solution detecting the presence of Fe2+, Co2+ and Cu2+ ions in the solution. The minimum detection limit observed was 1 × 10-7 M using UV-visible spectroscopy. Further, the applicability of the sensing material was also tested for a mixture of co-existing ions in solution to demonstrate the practical applicability of the system. Insight into the probable mechanistic pathway involved in the detection process is also being discussed.

  13. Layered P2-Na 2/3 Co 1/2 Ti 1/2 O 2 as a high-performance cathode material for sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sabi, Noha; Doubaji, Siham; Hashimoto, Kazuki; Komaba, Shinichi; Amine, Khalil; Solhy, Abderrahim; Manoun, Bouchaib; Bilal, Essaid; Saadoune, Ismael

    2017-02-01

    Layered oxides are regarded as promising cathode materials for sodium-ion batteries. We present Na2/3Co1/2Ti1/2O2 as a potential new cathode material for sodium-ion batteries. The crystal features and morphology of the pristine powder were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The cathode material is evaluated in galvanostatic charge-discharge and galvanostatic intermittent titration tests, as well as ex-situ X-ray diffraction analysis. Synthesized by a high-temperature solid state reaction, Na2/3Co1/2Ti1/2O2 crystallizes in P2-type structure with P6(3)/mmc space group. The material presents reversible electrochemical behavior and delivers a specific discharge capacity of 100 mAh g(-1) when tested in Na half cells between 2.0 and 4.2 V (vs. Na+/Na), with capacity retention of 98% after 50 cycles. Furthermore, the electrochemical cycling of this titanium-containing material evidenced a reduction of the potential jumps recorded in the NaxCoO2 parent phase, revealing a positive impact of Ti substitution for Co. The ex-situ XRD measurements confirmed the reversibility and stability of the material. No structural changes were observed in the XRD patterns, and the P2-type structure was stable during the charge/discharge process between 2.0 and 4.2 V vs. Na+/Na. These outcomes will contribute to the progress of developing low cost electrode materials for sodium-ion batteries. (C) 2017 Elsevier B.V. All rights reserved.

  14. Effect of Nb and F Co-doping on Li1.2Mn0.54Ni0.13Co0.13O2 Cathode Material for High-Performance Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Lei Ming

    2018-04-01

    Full Text Available The Li1.2Mn0.54−xNbxCo0.13Ni0.13O2−6xF6x (x = 0, 0.01, 0.03, 0.05 is prepared by traditional solid-phase method, and the Nb and F ions are successfully doped into Mn and O sites of layered materials Li1.2Mn0.54Co0.13Ni0.13O2, respectively. The incorporating Nb ion in Mn site can effectively restrain the migration of transition metal ions during long-term cycling, and keep the stability of the crystal structure. The Li1.2Mn0.54−xNbxCo0.13Ni0.13O2−6xF6x shows suppressed voltage fade and higher capacity retention of 98.1% after 200 cycles at rate of 1 C. The replacement of O2− by the strongly electronegative F− is beneficial for suppressed the structure change of Li2MnO3 from the eliminating of oxygen in initial charge process. Therefore, the initial coulombic efficiency of doped Li1.2Mn0.54−xNbxCo0.13Ni0.13O2−6xF6x gets improved, which is higher than that of pure Li1.2Mn0.54Co0.13Ni0.13O2. In addition, the Nb and F co-doping can effectively enhance the transfer of lithium-ion and electrons, and thus improving rate performance.

  15. Ionization of water clusters by fast Highly Charged Ions: Stability, fragmentation, energetics and charge mobility

    International Nuclear Information System (INIS)

    Legendre, S; Maisonny, R; Capron, M; Bernigaud, V; Cassimi, A; Gervais, B; Grandin, J-P; Huber, B A; Manil, B; Rousseau, P; Tarisien, M; Adoui, L; Lopez-Tarifa, P; AlcamI, M; MartIn, F; Politis, M-F; Penhoat, M A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study dissociative ionization of water clusters by impact of fast Ni ions. Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized clusters. An unusual stability of the (H 2 O) 4 H ''+ ion is observed, which could be the signature of the so called ''Eigen'' structure in gas phase water clusters. High charge mobility, responsible for the formation of protonated water clusters that dominate the mass spectrum, is evidenced. These results are supported by CPMD and TDDFT simulations, which also reveal the mechanisms of such mobility.

  16. The mobilies of chiral molecular cluster ions in He gas

    International Nuclear Information System (INIS)

    Saito, Kazuyuki; Matoba, Shiro; Koizumi, Tetsuo; Kojima, Takao M; Tanuma, Hajime; Shiromaru, Haruo

    2012-01-01

    We measured the mobilities of Li + -(2-butanol) and Li + -(limonene) ions in He gas at room temperature using a drift tube mass spectrometer. The zero field mobilities of Li + -(2-Butanol) and Li + -(Limonene) were much lower than the polarization limit, indicating that the geometric collision cross-sections between the cluster ions and He atom were larger than the cross-sections predicted by the presence of a polarization force alone.

  17. Synthesis and Characterization of Rh—Co Butterfly Clusters Capped by Functionally Substituted 1—Alkynes

    Institute of Scientific and Technical Information of China (English)

    ZHUBao-Hua; SUNJie; 等

    2003-01-01

    By the reactions of [Rh2Co2(CO2)12]1 with functionaly substituted alkyne ligands HC≡CR 2(R=FeCp2) and 3(R=2-OH-C6H4COOCH2),respectively in n-hexane at room temperature,two new cluster derivatives [Rh2Co2(CO)6(μ-CO)4(μ4,η2-HC≡CR)] 4(R=FeCp2) and 5 (R=2-OH-C6H4COOCH2) were obtained respectively,The alkyne was inserted into the Co-Co bond of cluster 1 to give two butterfly clusters.Cluster 4 has been determined by single-crystal X-ray diffraction,Crystallographic data:C22H10Co2FeO18Rh2,Mr=813.83,orthorhombic ,space group P212121,a=11.53187(7),b=12.6572(7),c=17.018(1)°↑A,V=2483.9(3)°↑A3,Z=4,Dc=2.176 g/cm3,F(000)=1568,μ=3.233mm-1,the final R=0.0366 and wR=0.0899 for 5367 observed reflections with I>2σ(I).The two clusters have also been characterized by elemental analysis ,IR and 1H-NMR spectroscopy.

  18. Ion Internal Excitation and Co++ 2 Reactivity: Effect On The Titan, Mars and Venus Ionospheric Chemistry

    Science.gov (United States)

    Nicolas, C.; Zabka, J.; Thissen, R.; Dutuit, O.; Alcaraz, C.

    In planetary ionospheres, primary molecular and atomic photoions can be produced with substantial electronic and vibrational internal energy. In some cases, this is known to strongly affect both the rate constants and the branching ratio between the reac- tion products. A previous experimental study (Nicolas et al.) made at the Orsay syn- chrotron radiation facility has shown that many endothermic charge transfer reactions which were not considered in the ionospheric chemistry models of Mars, Venus and Earth have to be included because they are driven by electronic excitation of the parent ions. New measurements on two important reactions for Titan and Mars ionospheres, N+ + CH4 and O+ + CO2, will be presented. Branching ratios between products are very different when the parent atomic ions are prepared in their ground states, N+(3P) and O+(4S), or in their first electronic metastable states N+(1D) and O+(2D or P). 2 As the lifetime of these states are long enough, they survive during the mean time be- tween two collisions in the ionospheric conditions. So, the reactions of these excited states must be included in the ionospheric models. Absolute cross section measurements of the reactivity of stable doubly charged molec- ular ions CO++ and their implications for the Martian ionosphere will also be pre- 2 sented. The molecular dication CO++ production by VUV photoionisation and elec- 2 tron impact in the upper ionosphere of Mars is far from being negligible. However, to determine its concentration, it was necessary to evaluate the major loss channels of these ions. For this purpose, we measured the absolute reaction cross section of the sta- ble dications with CO2, the major neutral species of the Mars ionosphere. CO++ ions 2 were produced either by photoionisation or by electron impact, and a reaction cross section of 45 Å2 with 13CO2 was measured. The reaction leads to charge transfer or to collision induced dissociation. These results were integrated in a model

  19. Synthesis and chemistry of the open-cage cobaltaheteroborane cluster [{(η(5)-C5Me5)Co}2B2H2Se2]: a combined experimental and theoretical study.

    Science.gov (United States)

    Barik, Subrat Kumar; Dorcet, Vincent; Roisnel, Thierry; Halet, Jean-François; Ghosh, Sundargopal

    2015-08-28

    Reaction of [(η(5)-C5Me5)CoCl]2 with a two-fold excess of [LiBH4·thf] followed by heating with an excess of Se powder produces the dicobaltaselenaborane species [{(η(5)-C5Me5)Co}2B2H2Se2], , in good yield. The geometry of resembles a nido pentagonal [Co2B2Se2] bipyramid with a missing equatorial vertex. It can alternatively be seen as an open cage triple-decker cluster. Isolation of permits its reaction with [Fe2(CO)9] to give heterometallic diselenametallaborane [{(η(5)-C5Me5)Co}Fe(CO)3B2H2Se2], . The geometry of is similar to that of with one of the [(η(5)-C5Me5)Co] groups replaced by the isolobal, two-electron fragment [Fe(CO)3]. Both new compounds have been characterized by mass spectrometry, and by (1)H, (11)B and (13)C NMR spectroscopy. The structural architectures have been unequivocally established by crystallographic analysis. In addition, density functional theory calculations were performed to investigate the bonding and electronic properties. The large HOMO-LUMO gaps computed for both clusters are consistent with their thermodynamic stability. Natural bond order calculations predict the absence of metal-metal bonding interaction.

  20. Planar CoB18- Cluster: a New Motif for - and Metallo-Borophenes

    Science.gov (United States)

    Chen, Teng-Teng; Jian, Tian; Lopez, Gary; Li, Wan-Lu; Chen, Xin; Li, Jun; Wang, Lai-Sheng

    2016-06-01

    Combined Photoelectron Spectroscopy (PES) and theoretical calculations have found that anion boron clusters (Bn-) are planar and quasi-planar up to B25-. Recent works show that anion pure boron clusters continued to be planar at B27-,B30-,B35- and B36-. B35- and B36- provide the first experimental evidence for the viability of the two-dimensional (2D) boron sheets (Borophene). The 2D to three-dimensional (3D) transitions are shown to happen at B40-,B39- and B28-, which possess cage-like structures. These fullerene-like boron cage clusters are named as Borospherene. Recently, borophenes or similar structures are claimed to be synthesized by several groups. Following an electronic design principle, a series of transition-metal-doped boron clusters (M©Bn-, n=8-10) are found to possess the monocyclic wheel structures. Meanwhile, CoB12- and RhB12- are revealed to adopt half-sandwich-type structures with the quasi-planar B12 moiety similar to the B12- cluster. Very lately, we show that the CoB16- cluster possesses a highly symmetric Cobalt-centered drum-like structure, with a new record of coordination number at 16. Here we report the CoB18- cluster to possess a unique planar structure, in which the Co atom is doped into the network of a planar boron cluster. PES reveals that the CoB18- cluster is a highly stable electronic system with the first adiabatic detachment energy (ADE) at 4.0 eV. Global minimum searches along with high-level quantum calculations show the global minimum for CoB18- is perfectly planar and closed shell (1A1) with C2v symmetry. The Co atom is bonded with 7 boron atoms in the closest coordination shell and the other 11 boron atoms in the outer coordination shell. The calculated vertical detachment energy (VDE) values match quite well with our experimental results. Chemical bonding analysis by the Adaptive Natural Density Partitioning (AdNDP) method shows the CoB18- cluster is π-aromatic with four 4-centered-2-electron (4c-2e) π bonds and one 19

  1. Detection of CO emission in Hydra 1 cluster galaxies

    International Nuclear Information System (INIS)

    Huchtmeier, W.K.

    1990-01-01

    A survey of bright Hydra cluster spiral galaxies for the CO(1-0) transition at 115 GHz was performed with the 15m Swedish-ESO submillimeter telescope (SEST). Five out of 15 galaxies observed have been detected in the CO(1-0) line. The largest spiral galaxy in the cluster, NGC 3312, got more CO than any spiral of the Virgo cluster. This Sa-type galaxy is optically largely distorted and disrupted on one side. It is a good candidate for ram pressure stripping while passing through the cluster's central region. A comparison with global CO properties of Virgo cluster spirals shows a relatively good agreement with the detected Hydra cluster galaxies

  2. Upgrading the Lyon cluster ion accelerator by a radiofrequency quadrupole

    International Nuclear Information System (INIS)

    Moser, H.O.; Schempp, A.

    1987-02-01

    The design is presented of an RFQ with variable final energy suitable to post-accelerate cluster ions from the Lyon electrostatic cluster-ion accelerator in the mass ranges from 1 to 25 μ and 1 to 50 μ to kinetic energies of 1.32-2.5 MeV and 2.64-5.0 MeV for cw and pulsed operation, respectively. Furthermore, a beam line is described which matches the electrostatically preaccelerated beam to the RFQ by use of electrostatic quadrupole triplets. When used without RFQ this beam line serves to improve beam parameters on the target, such as the particle flux density or beam divergence. The estimated costs of this project are about DM 345 000.- or FF 1 200 000.- without VAT. (orig.) [de

  3. Low temperature EPR investigation of Co2+ ion doped into rutile TiO2 single crystal: Experiments and simulations

    Science.gov (United States)

    Zerentürk, A.; Açıkgöz, M.; Kazan, S.; Yıldız, F.; Aktaş, B.

    2017-02-01

    In this paper, we present the results of X-band EPR spectra of Co2+ ion doped rutile (TiO2) which is one of the most promising memristor material. We obtained the angular variation of spectra in three mutually perpendicular planes at liquid helium (7-13 K) temperatures. Since the impurity ions have ½ effective spin and 7/2 nuclear spin, a relatively simple spin Hamiltonian containing only electronic Zeeman and hyperfine terms was utilized. Two different methods were used in theoretical analysis. Firstly, a linear regression analysis of spectra based on perturbation theory was studied. However, this approach is not sufficient for analyzing Co+2 spectra and leads to complex eigenvectors for G and A tensors due to large anisotropy of eigenvalues. Therefore, all spectra were analyzed again with exact diagonalization of spin Hamiltonian and the high accuracy eigenvalues and eigenvectors of G and A tensors were obtained by taking into account the effect of small sample misalignment from the exact crystallographic planes due to experimental conditions. Our results show that eigen-axes of g and A tensors are parallel to crystallographic directions. Hence, our EPR experiments proves that Co2+ ions substitute for Ti4+ ions in lattice. The obtained principal values of g tensor are gx=2.110(6), gy=5.890(2), gz=3.725(7) and principal values of hyperfine tensor are Ax=42.4, Ay=152.7, Az=26 (in 10-4/cm).

  4. Co+ -ion implantation induced doping of nanocrystalline CdS thin films: structural, optical, and vibrational properties

    International Nuclear Information System (INIS)

    Chandramohan, S.; Sarangi, S.N.; Majumder, S.; Som, T.; Kanjilal, A.; Sathyamoorthy, R.

    2009-01-01

    Full text: Transition metal (Mn, Fe, Co and Ni) doped CdS nanostructures and nanocrystalline thin films have attracted much attention due to their anticipated applications in magneto-optical, non-volatile memory and future spintronics devices. Introduction of impurities in substitutional positions is highly desirable for such applications. Ion implantation is known to provide many advantages over conventional methods for efficient doping and possibility of its seamless integration with device processing steps. It is not governed by equilibrium thermodynamics and offers the advantages of high spatial selectivity and to overcome the solubility limits. In this communication, we report on modifications of structural morphological, optical, and vibrational properties of 90 keV Co + -ion implanted CdS thin films grown by thermal evaporation. Co + -ion implantation was performed in the fluence range of 0.1-3.6x10 16 ions cm -2 These fluences correspond to Co concentration in the range of 0.34-10.8 at % at the peak position of profile. Implantation was done at an elevated temperature of 573 K in order to avoid amorphization and to enhance the solubility of Co ions in the CdS lattice. Films were characterized by glancing angle X-ray diffraction (GAXRD), atomic force microscopy (AFM), optical absorption, and micro-Raman spectroscopy. Implantation does not lead to any secondary phase formation either in the form of impurity or the metallic clusters. However, implantation improves the crystalline quality of the samples and leads to supersaturation of Co ions in the CdS lattice. Thus, nanocrystalline CdS thin films can be considered as a good radiation- resistant material, which can be employed for prolonged use in solar cells for space applications. The optical band gap is found to decrease systematically with increasing ion fluence from 2.39 to 2.28 eV. Implantation leads to agglomeration of grains and a systematic increase in the surface roughness. Both GAXRD and micro

  5. (Electronic structure and reactivities of transition metal clusters)

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The following are reported: theoretical calculations (configuration interaction, relativistic effective core potentials, polyatomics, CASSCF); proposed theoretical studies (clusters of Cu, Ag, Au, Ni, Pt, Pd, Rh, Ir, Os, Ru; transition metal cluster ions; transition metal carbide clusters; bimetallic mixed transition metal clusters); reactivity studies on transition metal clusters (reactivity with H{sub 2}, C{sub 2}H{sub 4}, hydrocarbons; NO and CO chemisorption on surfaces). Computer facilities and codes to be used, are described. 192 refs, 13 figs.

  6. Extraction of Co ions from ion-exchange resin by supercritical carbon dioxide

    International Nuclear Information System (INIS)

    Ju, Min Su; Koh, Moon Sung; Yang, Sung Woo; Park, Kwang Heon; Kim, Hak Won; Kim, Hong Doo

    2005-01-01

    There are a number of liquid treatment processes for eliminating radioactive ionic contaminants in nuclear facilities. One of the most common treatment methods for aqueous streams is the use of ion exchange, which is a well-developed technique that has been employed for many years in the nuclear industry. More specifically speaking, systems that ion exchange method is applied to in nuclear power plants are liquid radioactive waste treatment system, chemical and volume control system, steam generator blowdown treatment system, and service water supply system. During the operation of nuclear power plants, radioactive contaminants such as Co-60, Mn-54, Fe-59 and Cs-137 are contained in liquid radioactive wastes. And the wastes containing small amount of uranium are generated in nuclear fuel cycle facilities. To treat the liquid radioactive waste, we usually install ion exchangers rather than evaporators due to their simplicity and effectiveness, and this trend is increasing. However, the ion exchange process produces large volume of spent organic resin, and has some problems of radiation damage and thermal instability. And the reuse of the resin is limited due to the degradation of ion-exchanging ability. For this reason, were should consider a better method to expand the lifetime of the resin or to reduce the volume of radioactive resin wastes by extracting radioactive contaminants located in the resin. Supercritical fluid CO 2 has many good points as a process solvent that include low viscosity, negligible surface tension, and variable selectivity. And supercritical fluids have physical properties of both liquid and gas such as good penetration with a high dissolution capability. Supercritical fluids have been widely used in extraction, purification, and recovery processes. A number of workers applied supercritical CO 2 solvent for cleaning of precision devices and waste treatments. Since supercritical CO 2 has its mild critical point at 31 and 73.8bar as .deg. C

  7. Chemical Bonding of Transition-Metal Co13 Clusters with Graphene.

    Science.gov (United States)

    Alonso-Lanza, Tomás; Ayuela, Andrés; Aguilera-Granja, Faustino

    2015-12-01

    We carried out density functional calculations to study the adsorption of Co13 clusters on graphene. Several free isomers were deposited at different positions with respect to the hexagonal lattice nodes, allowing us to study even the hcp 2d isomer, which was recently obtained as the most stable one. Surprisingly, the Co13 clusters attached to graphene prefer icosahedron-like structures in which the low-lying isomer is much distorted; in such structures, they are linked with more bonds than those reported in previous works. For any isomer, the most stable position binds to graphene by the Co atoms that can lose electrons. We find that the charge transfer between graphene and the clusters is small enough to conclude that the Co-graphene binding is not ionic-like but chemical. Besides, the same order of stability among the different isomers on doped graphene is kept. These findings could also be of interest for magnetic clusters on graphenic nanostructures such as ribbons and nanotubes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Gas cluster ion beam equipments for industrial applications

    International Nuclear Information System (INIS)

    Matsuo, J.; Takaoka, G.H.; Yamada, I.

    1995-01-01

    30 keV and 200 keV gas cluster ion beam equipments have been developed for industrial applications. A gas cluster source with a non-cooled nozzle was used for both the equipments. Sufficient monomer ion suppression was achieved by using an ExB filter and chromatic lenses mass filter with low extraction voltage. These equipments are suitable to be used for low-damage surface treatment of metals, insulators and semiconductors without heavy metal contamination. (orig.)

  9. Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO{sub 2} transformation

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, Ramasamy [Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625 009 (India); National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India); Thamaraichelvan, Arunachalam [Faculty of Allied Health Sciences, Chettinad Hospital & Research Institute, Kelambakkam, Tamilnadu 603 103 (India); Ganesan, Tharumeya Kuppusamy [Department of Chemistry, The American College, Madurai, Tamilnadu 625 002 (India); Viswanathan, Balasubramanian, E-mail: bvnathan@iitm.ac.in [National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India)

    2017-02-28

    Highlights: • On interaction with adsorbate CO{sub 2,} the adsorbent changes its configuration around the metal. • Electron transfer is faster in low coordinative environment of Cu. • CO formation is more favorable on Cu sites with even coordination number. • Cu at coordination number two has a over potential of −0.35 V. - Abstract: Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO{sub 2} to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO{sub 2} to CO at an applied potential of −0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO{sub 2} to various value added chemicals.

  10. Critical current densities and flux creep rate in Co-doped BaFe2As2 with columnar defects introduced by heavy-Ion irradiation

    International Nuclear Information System (INIS)

    Nakajima, Y.; Tsuchiya, Y.; Taen, T.; Yagyuda, H.; Tamegai, T.; Okayasu, S.; Sasase, M.; Kitamura, H.; Murakami, T.

    2010-01-01

    We report the formation of columnar defects in Co-doped BaFe 2 As 2 single crystals with different heavy-ion irradiations. The formation of columnar defects by 200 MeV Au ion irradiation is confirmed by transmission electron microscopy and their density is about 40% of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density J c is enhanced in the 200 MeV Au and 800 MeV Xe ion irradiated samples while J c is unchanged in the 200 MeV Ni ion irradiated sample. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe 2 As 2 and cuprate superconductors.

  11. Probing thin over layers with variable energy/cluster ion beams

    International Nuclear Information System (INIS)

    Spool, A.; White, R.

    2006-01-01

    A series of carbon-coated magnetic recording disks proved ideal for exploring sampling depth and ion formation trends as a function of variations in energy and cluster size (Au x ) of the primary ion beam, and variations in over coat thickness and type. Ion yield from the underlying metal layer increased with increasing energy and decreasing cluster size of the primary ions. The yields varied nearly linearly with over layer thickness. In contrast, M x Cs y depth profiles were unaffected by changes in the primary ion. The samples were fortuitously dosed with dinonyl phthalate, allowing a study similar to prior GSIMS work [I.S. Gilmore, M.P. Seah, J.E. Johnstone, in: A. Benninghoven, P. Bertrand, H.-N. Migeon, H.W. Werner (Eds.), Proceedings of the 12th International Conference on SIMS, Elsevier, Brussels, 2000, p. 801]. Ions prominent in the EI mass spectrum, including even electron ions, were more consistently enhanced at lower energies and higher cluster sizes than the primary (M + H) + ion. The total secondary ion count was inversely proportional to the film thickness. Secondary electrons, largely originating in the buried metal layer, may be inducing organic ion formation [A.M. Spool, Surf. Interface Anal. 36 (2004) 264

  12. Enhancement in anomalous Hall resistivity of Co/Pd multilayer and CoPd alloy by Ga+ ion irradiation

    KAUST Repository

    Guo, Zaibing

    2014-02-01

    In this paper, we report the effect of Ga+ ion irradiation on anomalous Hall effect (AHE) and longitudinal resistivity (ρxx) in [Co(3 Å)/Pd(5 Å)]80 multilayer and Co 42Pd58 alloy. 4- and 2-fold increases in anomalous Hall resistivity (ρAH) in the Co/Pd multilayer and CoPd alloy have been observed after irradiations at doses of 2.4 × 1015 and 3.3×10 15 ions/cm2, respectively. Skew scattering and side jump contributions to AHE have been analyzed based on the scaling relationship ρAH = aρxx + bρ2xx. For the Co/Pd multilayer, AHE is mainly affected by ion irradiation-induced interface diffusion and defects. For the CoPd alloy, the increase in doses above 1.5 × 1015 ions/cm2 induces a sign change in skew scattering, followed by the skew scattering contribution to AHE overwhelming the side jump contribution, this phenomenon should be attributed to irradiation-induced defects and modifications in chemical ordering. © Copyright EPLA, 2014.

  13. One-pot fabrication of graphene sheets decorated Co2P-Co hollow nanospheres for advanced lithium ion battery anodes

    International Nuclear Information System (INIS)

    Xie, Qingshui; Zeng, Deqian; Gong, Pingyun; Huang, Jian; Ma, Yating; Wang, Laisen; Peng, Dong-Liang

    2017-01-01

    Highlights: • Co 2 P-Co hollow nanospheres with graphene sheets decoration are prepared through one-pot solution approach. • Co 2 P-Co/graphene nanocomposites reveal greatly enhanced lithium storage performances than Co 2 P-Co counterparts. • The superb electrochemical performances derive from dual modification of graphene sheets and metal Co as well as their hollow configuration. - Abstract: The fabrication of Co 2 P-Co (Co-P composites) hollow nanospheres with graphene sheets decoration through one-pot solution approach is demonstrated and their potential as the anode materials for lithium ion batteries is assessed. A large specific capacity of 929 mA h g −1 can be retained for Co-P/graphene nanocomposites at 100 mA g −1 after 200 cycles. When cycled at a large current density of 2.0C, the Co-P/graphene nanocomposites deliver a decent reversible capacity of 567 mA h g −1 , which is much higher than the theoretical capacity of traditional graphite anode (372 mA h g −1 ). The obviously enhanced lithium storage properties of Co-P/graphene nanocomposites are put down to the dual modification of graphene sheets and metal Co as well as their hollow structures.

  14. Influence of Structure and Charge State on the Mechanism of CO Oxidation on Gold Clusters

    Science.gov (United States)

    Johnson, Grant; Burgel, Christian; Reilly, Nelly; Mitric, Roland; Kimble, Michele; Tyo, Eric; Castleman, A. W.; Bonacic-Koutecky, Vlasta

    2008-05-01

    Gas-phase reactivity experiments and high level theoretical calculations have been employed to study the interaction of both positively and negatively charged gold oxide clusters with carbon monoxide (CO). We demonstrate that for negatively charged clusters CO is oxidized to CO2 by an Eley-Ridel-like (ER-) mechanism involving the attack of CO on oxygen rather than gold. In contrast, for positively charged clusters, the oxidation reaction may also occur by a Langmuir-Hinshelwood-like (LH-) mechanism involving the initial binding of CO to a gold atom followed by subsequent migration to an oxygen site. The LH mechanism is made possible through the large energy gain associated with the adsorption of two CO molecules onto cationic gold clusters. Structure-reactivity relationships are also established which demonstrate that terminally bound oxygen atoms are the most active sites for CO oxidation. Bridge bonded oxygen atoms and molecularly bound O2 units are shown to be inert. We also establish an inverse relationship between the binding energy of CO to gold clusters and the energy of the clusters lowest unoccupied molecular orbital (LUMO).

  15. Electronic structure and dynamics of ordered clusters with ME or RE ions on oxide surface

    Energy Technology Data Exchange (ETDEWEB)

    Kulagin, N.A., E-mail: nkulagin@bestnet.kharkov.u [Kharkiv National University for Radio Electronics, Avenue Shakespeare 6-48, 61045 Kharkiv (Ukraine)

    2011-03-15

    Selected data of ab initio simulation of the electronic structure and spectral properties of either cluster with ions of iron, rare earth or actinium group elements have been presented here. Appearance of doped Cr{sup +4} ions in oxides, Cu{sup +2} in HTSC, Nd{sup +2} in solids has been discussed. Analysis of experimental data for plasma created ordered structures of crystallites with size of about 10{sup -9} m on surface of separate oxides are given, too. Change in the spectroscopic properties of clusters and nano-structures on surface of strontium titanate crystals discussed shortly using the X-ray line spectroscopy experimental results. - Research highlights: External influence and variation of technology induce changes in valence of nl ions in compounds. Wave function of cluster presented as anti-symmetrical set of ions wave functions. The main equation describes the self-consistent field depending on state of all electrons of cluster. Level scheme of Cr{sup 4+} ions in octo- and tetra-site corresponds to doped oxides spectra after treatment. Plasma treatment effects in appearance of systems of unit crystallites with size of about 10{sup -6}-10{sup -9} m.

  16. Electronic structure and dynamics of ordered clusters with ME or RE ions on oxide surface

    International Nuclear Information System (INIS)

    Kulagin, N.A.

    2011-01-01

    Selected data of ab initio simulation of the electronic structure and spectral properties of either cluster with ions of iron, rare earth or actinium group elements have been presented here. Appearance of doped Cr +4 ions in oxides, Cu +2 in HTSC, Nd +2 in solids has been discussed. Analysis of experimental data for plasma created ordered structures of crystallites with size of about 10 -9 m on surface of separate oxides are given, too. Change in the spectroscopic properties of clusters and nano-structures on surface of strontium titanate crystals discussed shortly using the X-ray line spectroscopy experimental results. - Research highlights: → External influence and variation of technology induce changes in valence of nl ions in compounds. → Wave function of cluster presented as anti-symmetrical set of ions wave functions. → The main equation describes the self-consistent field depending on state of all electrons of cluster. → Level scheme of Cr 4+ ions in octo- and tetra-site corresponds to doped oxides spectra after treatment. → Plasma treatment effects in appearance of systems of unit crystallites with size of about 10 -6 -10 -9 m.

  17. Size and composition dependence of the frozen structures in Co-based bimetallic clusters

    International Nuclear Information System (INIS)

    Li, Guojian; Wang, Qiang; Cao, Yongze; Du, Jiaojiao; He, Jicheng

    2012-01-01

    This Letter studies the size-dependent freezing of Co, Co–Ni, and Co–Cu clusters by using molecular dynamics with embedded atom method. Size effect occurs in these three types of clusters. The clusters with large sizes always freeze to form their bulk-like structures. However, the frozen structures for small sizes are generally related to their compositions. The icosahedral clusters are formed for Co clusters (for ⩽3.2 nm diameter) and also for Co–Ni clusters but at a larger size range (for ⩽4.08 nm). Upon the Co–Cu clusters, decahedral structure is obtained for small size (for 2.47 nm). The released energy induced the structural transformation plays a key role in the frozen structures. These results indicate that the preformed clusters with special structures can be tuned by controlling their compositions and sizes. -- Highlights: ► The size effect occurs in the Co, Co–Ni, and Co–Cu clusters. ► The clusters with large sizes always freeze to form their bulk-like structures. ► The frozen structures for small sizes are generally related to their compositions. ► Icosahedron is formed for Co and also for Co–Ni but at a larger size range. ► Upon the Co–Cu clusters, decahedral structure is obtained for small size.

  18. Effect of Temperature on the Kinetics of Sorption of Co2+ and Ni2+ Ions by a Sorbent Based on an Inositol Hexaphosphoric Acid Derivative

    Science.gov (United States)

    Yarusova, S. B.; Makarenko, N. V.; Gordienko, P. S.; Karpenko, M. A.; Novikova, E. S.

    2018-03-01

    Data on the effect temperature has on the kinetics of the removal of Co2+ and Ni2+ ions under static conditions by a sorbent based on a derivative of phytic acid fabricated from rice production waste are presented. It is shown that when the temperature is raised from 20 to 60°C, the sorption capacity of the sorbent based on phytic acid increases over the period of sorption and within 180 min reaches values of 1.4 mmol g-1 for Co2+ ions and 1.3 mmol g-1 for Ni2+ ions. It is established that for the investigated range of temperatures, order n of the sorption of Co2+ and Ni2+ ions is frame is best described by a kinetic model of a pseudo-second order, as is indicated by respective correlation coefficients.

  19. Charge transfer processes in collisions of H+ ions with H2, D2, CO, CO2 CH4, C2H2, C2H6 and C3H8 molecules below 10 keV

    International Nuclear Information System (INIS)

    Kusakabe, T.; Buenker, R.J.; Kimura, M.

    2002-01-01

    Charge transfer processes resulting from collisions of H + ions with H 2 , D 2 , CO, CO 2 CH 4 , C 2 H 2 , C 2 H 6 and C 3 H 8 molecules have been investigated in the energy range of 0.2 to 4.0 keV experimentally and theoretically. The initial growth rate method was employed in the experiment for studying the dynamics and cross sections. Theoretical analysis based on a molecular-orbital expansion method for H 2 , D 2 , CO, CH 4 and C 2 H 2 targets was also carried out. The present results for the H 2 , CO and CO 2 molecules by H + impact are found to be in excellent accord with most of previous measurements above 1 keV, but they show some differences below this energy where our result displays a stronger energy-dependence. For CH 4 , C 2 H 2 , C 2 H 6 and C 3 H 8 targets, both experimental and theoretical results indicate that if one assumes vibrationally excited molecular ions (CH 4 + , C 2 H 2 + , C 2 H 6 + and C 3 H 8 + ) formed in the exit channel, then charge transfer processes sometimes become more favorable since these vibrationally excited fragments meet an accidental resonant condition. This is a clear indication of the role of vibrational excited states for charge transfer, and is an important realization for general understanding. (author)

  20. Range of plasma ions in cold cluster gases near the critical point

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, G. [Cyclotron Institute, Texas A& M University, 77843 College Station, TX (United States); Quevedo, H.J. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Bonasera, A., E-mail: abonasera@comp.tamu.edu [Cyclotron Institute, Texas A& M University, 77843 College Station, TX (United States); Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Donovan, M.; Dyer, G.; Gaul, E. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Guardo, G.L. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Gulino, M. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Libera Universita' Kore, 94100 Enna (Italy); La Cognata, M.; Lattuada, D. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Palmerini, S. [Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Pizzone, R.G.; Romano, S. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Smith, H. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States); Trippella, O. [Department of Physics and Geology, University of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Perugia, Via A. Pascoli, 06123 Perugia (Italy); Anzalone, A.; Spitaleri, C. [Laboratori Nazionali del Sud-INFN, via S. Sofia 64, 95123 Catania (Italy); Ditmire, T. [Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, TX 78712 (United States)

    2017-05-18

    We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid–gas phase transition. - Highlights: • We present experimental results obtained at the UT Petawatt laser facility, Austin, TX. • The ion range is strongly modified for cluster gases as compared to its value in a homogeneous system. • Large fluctuations are found if the cluster gas is prepared near the liquid–gas phase transition region.

  1. Range of plasma ions in cold cluster gases near the critical point

    International Nuclear Information System (INIS)

    Zhang, G.; Quevedo, H.J.; Bonasera, A.; Donovan, M.; Dyer, G.; Gaul, E.; Guardo, G.L.; Gulino, M.; La Cognata, M.; Lattuada, D.; Palmerini, S.; Pizzone, R.G.; Romano, S.; Smith, H.; Trippella, O.; Anzalone, A.; Spitaleri, C.; Ditmire, T.

    2017-01-01

    We measure the range of plasma ions in cold cluster gases by using the Petawatt laser at the University of Texas-Austin. The produced plasma propagated in all directions some hitting the cold cluster gas not illuminated by the laser. From the ratio of the measured ion distributions at different angles we can estimate the range of the ions in the cold cluster gas. It is much smaller than estimated using popular models, which take only into account the slowing down of charged particles in uniform matter. We discuss the ion range in systems prepared near a liquid–gas phase transition. - Highlights: • We present experimental results obtained at the UT Petawatt laser facility, Austin, TX. • The ion range is strongly modified for cluster gases as compared to its value in a homogeneous system. • Large fluctuations are found if the cluster gas is prepared near the liquid–gas phase transition region.

  2. Recombination of cluster ions

    Science.gov (United States)

    Johnsen, Rainer

    1993-01-01

    Some of our recent work on molecular band emissions from recombination of molecular dimer ions (N4(+) and CO(+) CO) is discussed. Much of the experimental work was done by Y. S. Cao; the results on N4(+) recombination have been published. A brief progress report is given on our ongoing measurements of neutral products of recombination using the flowing-afterglow Langmuir-probe technique in conjunction with laser-induced fluorescence.

  3. Ternary CNTs@TiO2/CoO Nanotube Composites: Improved Anode Materials for High Performance Lithium Ion Batteries

    Science.gov (United States)

    Madian, Mahmoud; Ummethala, Raghunandan; Abo El Naga, Ahmed Osama; Ismail, Nahla; Rümmeli, Mark Hermann; Eychmüller, Alexander; Giebeler, Lars

    2017-01-01

    TiO2 nanotubes (NTs) synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li+ ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs)@TiO2/CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO2/CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO2 and TiO2/CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li+ ion diffusivity, promoting a strongly favored lithium insertion into the TiO2/CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability. PMID:28773032

  4. Ternary CNTs@TiO2/CoO Nanotube Composites: Improved Anode Materials for High Performance Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Mahmoud Madian

    2017-06-01

    Full Text Available TiO2 nanotubes (NTs synthesized by electrochemical anodization are discussed as very promising anodes for lithium ion batteries, owing to their high structural stability, high surface area, safety, and low production cost. However, their poor electronic conductivity and low Li+ ion diffusivity are the main drawbacks that prevent them from achieving high electrochemical performance. Herein, we report the fabrication of a novel ternary carbon nanotubes (CNTs@TiO2/CoO nanotubes composite by a two-step synthesis method. The preparation includes an initial anodic fabrication of well-ordered TiO2/CoO NTs from a Ti-Co alloy, followed by growing of CNTs horizontally on the top of the oxide films using a simple spray pyrolysis technique. The unique 1D structure of such a hybrid nanostructure with the inclusion of CNTs demonstrates significantly enhanced areal capacity and rate performances compared to pure TiO2 and TiO2/CoO NTs, without CNTs tested under identical conditions. The findings reveal that CNTs provide a highly conductive network that improves Li+ ion diffusivity, promoting a strongly favored lithium insertion into the TiO2/CoO NT framework, and hence resulting in high capacity and an extremely reproducible high rate capability.

  5. Layered double hydroxides for preparing CoMn{sub 2}O{sub 4} nanoparticles as anodes of lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xu; Ma, Jingjing; Yuan, Ruo, E-mail: yuanruo@swu.edu.cn; Yang, Xia, E-mail: xiayang2@swu.edu.cn

    2017-06-15

    In the field of lithium-ion batteries, CoMn{sub 2}O{sub 4} as an anode material has attracted a wide attention because it inherited the splendid electrochemical performances of Mn and Co-based metal oxides. Compared to graphite, Co-based oxides have a higher capacity which is about twice of the graphite. Moreover, Mn-based oxides have lower operating voltages and manganese exists abundantly in nature. Layered double hydroxides (LDHs), similar with brucite structure, were used as precursor for CoMn{sub 2}O{sub 4} nanoparticles in this work. Under high temperature process, the LDHs decomposed to CoMn{sub 2}O{sub 4} nanoparticles. When evaluated as anode materials for lithium ion batteries, the CoMn{sub 2}O{sub 4} nanoparticles behaved good electrochemical performance with the discharge and charge capacity of 733 mAh g{sup -1} and 721 mAh g{sup -1} at current density of 200 mA g{sup -1} after 100 cycles. This method for preparing CoMn{sub 2}O{sub 4} nanoparticles is easy, which may provide a way for synthesis of other bimetallic oxides and anodes of lithium ion batteries. - Highlights: • Layered double hydroxides were employed as precursors to synthesize CoMn{sub 2}O{sub 4}. • The CoMn{sub 2}O{sub 4} nanoparticles behaved good electrochemical performance. • This study provides a guideline for preparing bimetallic oxides.

  6. Chemisorption on size-selected metal clusters: activation barriers and chemical reactions for deuterium and aluminum cluster ions

    International Nuclear Information System (INIS)

    Jarrold, M.F.; Bower, J.E.

    1988-01-01

    The authors describe a new approach to investigating chemisorption on size-selected metal clusters. This approach involves investigating the collision-energy dependence of chemisorption using low-energy ion beam techniques. The method provides a direct measure of the activation barrier for chemisorption and in some cases an estimate of the desorption energy as well. They describe the application of this technique to chemisorption of deuterium on size-selected aluminum clusters. The activation barriers increase with cluster size (from a little over 1 eV for Al 10 + to around 2 eV for Al 27 + ) and show significant odd-even oscillations. The activation barriers for the clusters with an odd number of atoms are larger than those for the even-numbered clusters. In addition to chemisorption of deuterium onto the clusters, chemical reactions were observed, often resulting in cluster fragmentation. The main products observed were Al/sub n-1/D + , Al/sub n-2/ + , and Al + for clusters with n + and Al/sub n-1/D + for the larger clusters

  7. Tailoring optical properties of TiO2-Cr co-sputtered films using swift heavy ions

    Science.gov (United States)

    Gupta, Ratnesh; Sen, Sagar; Phase, D. M.; Avasthi, D. K.; Gupta, Ajay

    2018-05-01

    Effect of 100 MeV Au7+ ion irradiation on structure and optical properties of Cr-doped TiO2 films has been studied using X-ray photoelectron spectroscopy, soft X-ray absorption spectroscopy, UV-Visible spectroscopy, X-ray reflectivity, and atomic force microscopy. X-ray reflectivity measurement implied that film thickness reduces as a function of ion fluence while surface roughness increases. The variation in surface roughness is well correlated with AFM results. Ion irradiation decreases the band gap energy of the film. Swift heavy ion irradiation enhances the oxygen vacancies in the film, and the extra electrons in the vacancies act as donor-like states. In valence band spectrum, there is a shift in the Ti3d peak towards lower energies and the shift is equivalent to the band gap energy obtained from UV spectrum. Evidence for band bending is also provided by the corresponding Ti XPS peak which exhibits a shift towards lower energy due to the downward band bending. X-ray absorption studies on O Kand Cr L3,2 edges clearly indicate that swift heavy ion irradiation induces formation of Cr-clusters in TiO2 matrix.

  8. Efficient visible light photocatalytic NO{sub x} removal with cationic Ag clusters-grafted (BiO){sub 2}CO{sub 3} hierarchical superstructures

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xin [Chongqing Key Laboratory of Catalysis and Functional Organic Molecules, College of Environment and Resources, Engineering Research Center for Waste Oil Recovery Technology and Equipment of Ministry of Education, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 40067 (China); Zhang, Wendong [Department of Scientific Research Management, Chongqing Normal University, Chongqing 401331 (China); Deng, Hua [State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Ni, Zilin [Department of Scientific Research Management, Chongqing Normal University, Chongqing 401331 (China); Dong, Fan, E-mail: dfctbu@126.com [Chongqing Key Laboratory of Catalysis and Functional Organic Molecules, College of Environment and Resources, Engineering Research Center for Waste Oil Recovery Technology and Equipment of Ministry of Education, College of Environment and Resources, Chongqing Technology and Business University, Chongqing 40067 (China); Zhang, Yuxin, E-mail: zhangyuxin@cqu.edu.cn [College of Materials Science and Engineering, National Key Laboratory of Fundamental Science of Micro/Nano-Devices and System Technology, Chongqing University, Chongqing 400044 (China)

    2017-01-15

    Graphical abstract: The cationic Ag clusters-grafted (BiO){sub 2}CO{sub 3} hierarchical superstructures exhibits highly enhanced visible light photocatalytic air purification through an interfacial charge transfer process induced by Ag clusters. - Highlights: • Microstructural optimization and surface cluster-grafting were firstly combined. • Cationic Ag clusters were grafted on the surface of (BiO){sub 2}CO{sub 3} superstructures. • The Ag clusters-grafted BHS displayed enhanced visible light photocatalysis. • Direct interfacial charge transfer (IFCT) from BHS to Ag clusters was proposed. • The charge transfer process and the dominant reactive species were revealed. - Abstract: A facile method was developed to graft cationic Ag clusters on (BiO){sub 2}CO{sub 3} hierarchical superstructures (BHS) surface to improve their visible light activity. Significantly, the resultant Ag clusters-grafted BHS displayed a highly enhanced visible light photocatalytic performance for NOx removal due to the direct interfacial charge transfer (IFCT) from BHS to Ag clusters. The chemical and coordination state of the cationic Ag clusters was determined with the extended X-ray absorption fine structure (EXAFS) and a theoretical structure model was proposed for this unique Ag clusters. The charge transfer process and the dominant reactive species (·OH) were revealed on the basis of electron spin resonance (ESR) trapping. A new photocatalysis mechanism of Ag clusters-grafted BHS under visible light involving IFCT process was uncovered. In addition, the cationic Ag clusters-grafted BHS also demonstrated high photochemical and structural stability under repeated photocatalysis runs. The perspective of enhancing photocatalysis through combination of microstructural optimization and IFCT could provide a new avenue for the developing efficient visible light photocatalysts.

  9. Robustness of cluster synchronous patterns in small-world networks with inter-cluster co-competition balance

    International Nuclear Information System (INIS)

    Zhang, Jianbao; Ma, Zhongjun; Chen, Guanrong

    2014-01-01

    All edges in the classical Watts and Strogatz's small-world network model are unweighted and cooperative (positive). By introducing competitive (negative) inter-cluster edges and assigning edge weights to mimic more realistic networks, this paper develops a modified model which possesses co-competitive weighted couplings and cluster structures while maintaining the common small-world network properties of small average shortest path lengths and large clustering coefficients. Based on theoretical analysis, it is proved that the new model with inter-cluster co-competition balance has an important dynamical property of robust cluster synchronous pattern formation. More precisely, clusters will neither merge nor split regardless of adding or deleting nodes and edges, under the condition of inter-cluster co-competition balance. Numerical simulations demonstrate the robustness of the model against the increase of the coupling strength and several topological variations

  10. Robustness of cluster synchronous patterns in small-world networks with inter-cluster co-competition balance

    Science.gov (United States)

    Zhang, Jianbao; Ma, Zhongjun; Chen, Guanrong

    2014-06-01

    All edges in the classical Watts and Strogatz's small-world network model are unweighted and cooperative (positive). By introducing competitive (negative) inter-cluster edges and assigning edge weights to mimic more realistic networks, this paper develops a modified model which possesses co-competitive weighted couplings and cluster structures while maintaining the common small-world network properties of small average shortest path lengths and large clustering coefficients. Based on theoretical analysis, it is proved that the new model with inter-cluster co-competition balance has an important dynamical property of robust cluster synchronous pattern formation. More precisely, clusters will neither merge nor split regardless of adding or deleting nodes and edges, under the condition of inter-cluster co-competition balance. Numerical simulations demonstrate the robustness of the model against the increase of the coupling strength and several topological variations.

  11. Robustness of cluster synchronous patterns in small-world networks with inter-cluster co-competition balance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianbao [School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Ma, Zhongjun, E-mail: mzj1234402@163.com [School of Mathematics and Computing Science, Guilin University of Electronic Technology, Guilin 541004 (China); Chen, Guanrong [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

    2014-06-15

    All edges in the classical Watts and Strogatz's small-world network model are unweighted and cooperative (positive). By introducing competitive (negative) inter-cluster edges and assigning edge weights to mimic more realistic networks, this paper develops a modified model which possesses co-competitive weighted couplings and cluster structures while maintaining the common small-world network properties of small average shortest path lengths and large clustering coefficients. Based on theoretical analysis, it is proved that the new model with inter-cluster co-competition balance has an important dynamical property of robust cluster synchronous pattern formation. More precisely, clusters will neither merge nor split regardless of adding or deleting nodes and edges, under the condition of inter-cluster co-competition balance. Numerical simulations demonstrate the robustness of the model against the increase of the coupling strength and several topological variations.

  12. The smoke ion source: A device for the generation of cluster ions via inert gas condensation

    International Nuclear Information System (INIS)

    McHugh, K.M.; Sarkas, H.W.; Eaton, J.G.; Bowen, K.H.; Westgate, C.R.

    1989-01-01

    We report the development of an ion source for generating intense, continuous beams of both positive and negative cluster ions. This device is the result of the marriage of the inert gas condensation method with techniques for injecting electrons directly into expanding jets. In the preliminary studies described here, we have observed cluster ion size distributions ranging from n=1-400 for Pb n + and Pb n - and from n=12-5700 for Li n - . (orig.)

  13. Structural and magnetic properties of ion-beam bombarded Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.W.; Guo, J.Y.; Lin, S.R.; Ouyang, H. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402 (China); Tsai, C.J. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300 (China); Van Lierop, J. [Department of Physics and Astronomy, University of Manitoba, Winnipeg (Canada); Phuoc, N.N.; Suzuki, T. [Information Storage Materials Laboratory, Toyota Technological Institute, Nagoya 468-8511 (Japan)

    2007-12-15

    A series of [Pt(2 nm)/Co(2 nm)]{sub 10}/Pt(30 nm) multilayers were deposited by using an ion-beam technique. X-ray diffraction and transmission electron microscopy results have shown that as-deposited samples consist of h.c.p. Co and f.c.c. Pt phases. Disordered CoPt{sub 3} phases were developed with increasing End-Hall voltage (V{sub EH}) that induces greater ion-beam bombardment energy during deposition. This indicates that intermixing of Co and Pt increases with ion-beam bombardment. The coercivities (ranging from 100 Oe to 300 Oe) of Co/Pt multilayers decreased with increasing V{sub EH}. After annealing, the formation of CoPt{sub 3} was observed in these ion-beam bombarded samples, resulting in lower coercivities (H{sub c}{proportional_to} 50 Oe). The depressed transition temperature of CoPt{sub 3} for films deposited with the largest V{sub EH} was attributed to distorted CoPt{sub 3} structures that appeared with annealing. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Exchange Bias in Layered GdBaCo2O5.5 Cobaltite

    Science.gov (United States)

    Solin, N. I.; Naumov, S. V.; Telegin, S. V.; Korolev, A. V.

    2017-12-01

    It is established that excess oxygen content δ influences the exchange bias (EB) in layered GdBa-Co2O5 + δ cobaltite. The EB effect arises in p-type (δ > 0.5) cobaltite and disappears in n-type (δ training effect inherent in systems with EB has been studied. The results are explained in terms of exchange interaction between the FM and AFM phases. It is assumed that the EB originates from the coexistence of Co3+ and Co4+ ions that leads to the formation of monodomain FM clusters in the AFM matrix of cobaltite.

  15. Novel radial vanadium pentoxide nanobelt clusters for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanping; Zhong, Wenwu [Department of Physics and Electronic Engineering, Taizhou University, Taizhou, Zhejiang 318000 (China); Du, Yinxiao, E-mail: duyinxiao@zzia.edu.cn [Department of Mathematics and Physics, Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou 450015 (China); Yuan, Q.X. [Department of Mathematics and Physics, Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou 450015 (China); Wang, Xu [School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi' an 710071 (China); Jia, Renxu, E-mail: rxjia@mail.xidian.edu.cn [School of Microelectronics, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi' an 710071 (China)

    2015-06-05

    Highlights: • Radial V{sub 2}O{sub 5} nanobelt clusters were synthesized by a novel hydrothermal process. • The V{sub 2}O{sub 5} clusters are single crystallites with [0 1 0] growth direction. • Specific discharge capacity of V{sub 2}O{sub 5} is 134 mA h/g coupled with good cycle stability. - Abstract: This paper reports the synthesis, characterization and Li-ion intercalation properties of moundlily-like radial vanadium pentoxide (V{sub 2}O{sub 5}) nanobelt clusters. The V{sub 2}O{sub 5} nanobelt clusters was successfully synthesized by a novel soft template assisted hydrothermal process followed by thermal annealing. The as-prepared products were characterized by X-ray diffraction, thermogravimetric analysis, FT-IR spectrometry, scanning electron microscopy and high resolution transmission electron microscopy. The obtained V{sub 2}O{sub 5} possesses a single-crystalline structure with a preferred orientation along the [0 1 0] crystal plane. Electrochemical analysis shows that the specific discharge capacity of the V{sub 2}O{sub 5} nanobelt clusters reaches 134 mA h/g at a current density of 2 A/g coupled with good cycle stability.

  16. Cluster Ion Implantation in Graphite and Diamond

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2014-01-01

    Cluster ion beam technique is a versatile tool which can be used for controllable formation of nanosize objects as well as modification and processing of surfaces and shallow layers on an atomic scale. The current paper present an overview and analysis of data obtained on a few sets of graphite...... and diamond samples implanted by keV-energy size-selected cobalt and argon clusters. One of the emphases is put on pinning of metal clusters on graphite with a possibility of following selective etching of graphene layers. The other topic of concern is related to the development of scaling law for cluster...... implantation. Implantation of cobalt and argon clusters into two different allotropic forms of carbon, namely, graphite and diamond is analysed and compared in order to approach universal theory of cluster stopping in matter....

  17. Mass spectrometric probes of metal cluster distributions and metastable ion decay

    International Nuclear Information System (INIS)

    Parks, E.K.; Liu, K.; Cole, S.K.; Riley, S.J.

    1988-01-01

    The study of metal clusters has provided both an opportunity and a challenge to the application of mass spectrometry. These days the most often-used technique for cluster generation - laser vaporization - leads to extensive distributions of cluster sizes, from one to perhaps thousands of atoms, and most studies reported to date use excimer laser ionization and time-of-flight mass spectrometry for cluster detection. Our apparatus is a simple one-stage TOF design employing Wiley-McLauren spatial focusing and a one-meter drift tube. In a second apparatus employing a pulsed valve in the cluster source, we see asymmetric broadening of niobium cluster mass peaks under multiphoton ionization conditions, indicating metastable decay of parent cluster ions. Other studies of niobium clusters have shown no such asymmetric peaks. 2 figs

  18. Energetics and dynamics of the neutralization of clustered ions in ammonia and water vapour

    International Nuclear Information System (INIS)

    Sennhauser, E.S.; Armstrong, D.A.

    1978-01-01

    The energetics and dynamics of neutralization reactions of clustered ions in ammonia and water vapour have been analysed. Neutralization rate coefficients were calculated for the ions in ammonia and for H + .(H 2 O)sub(n) combining with various clustered anions in water vapour up to densities of 4 x 10 19 molecule cm -3 at 390 K. In the case of ammonia, calculations were also performed at 298 K. For all systems, fractional contributions of the neutralization coefficients for specific cluster sizes to the overall coefficient αsub(eff) were evaluated. The computed value of αsub(eff) for NH 3 was in reasonable agreement with experimental data in the [NH 3 ] range 0.3 to 4 x 10 19 molecule cm -3 , and general trends stemming from the effects of increasing ion mass were pointed out. Calculations of energies of individual cluster sizes indicate possible neutralization reaction mechanisms. With some exception, proton transfer is the only possible path and no H atoms should be formed. This is in general agreement with literature results for water vapour at approximately 390 K and with [H 2 O] >= 2 x 10 x 10 19 molecule cm -3 . (author)

  19. CO2 solubility in aqueous solutions containing Na+, Ca2+, Cl−, SO42− and HCO3-: The effects of electrostricted water and ion hydration thermodynamics

    International Nuclear Information System (INIS)

    Gilbert, Kimberly; Bennett, Philip C.; Wolfe, Will; Zhang, Tongwei; Romanak, Katherine D.

    2016-01-01

    Dissolution of CO 2 into deep subsurface brines for carbon sequestration is regarded as one of the few viable means of reducing the amount of CO 2 entering the atmosphere. Ions in solution partially control the amount of CO 2 that dissolves, but the mechanisms of the ion's influence are not clearly understood and thus CO 2 solubility is difficult to predict. In this study, CO 2 solubility was experimentally determined in water, NaCl, CaCl 2 , Na 2 SO 4, and NaHCO 3 solutions and a mixed brine similar to the Bravo Dome natural CO 2 reservoir; ionic strengths ranged up to 3.4 molal, temperatures to 140 °C, and CO 2 pressures to 35.5 MPa. Increasing ionic strength decreased CO 2 solubility for all solutions when the salt type remained unchanged, but ionic strength was a poor predictor of CO 2 solubility in solutions with different salts. A new equation was developed to use ion hydration number to calculate the concentration of electrostricted water molecules in solution. Dissolved CO 2 was strongly correlated (R 2  = 0.96) to electrostricted water concentration. Strong correlations were also identified between CO 2 solubility and hydration enthalpy and hydration entropy. These linear correlation equations predicted CO 2 solubility within 1% of the Bravo Dome brine and within 10% of two mixed brines from literature (a 10 wt % NaCl + KCl + CaCl 2 brine and a natural Na + , Ca 2+ , Cl − type brine with minor amounts of Mg 2+ , K + , Sr 2+ and Br − ). - Highlights: • Measured CO 2 solubility in Na + , Cl − , HCO 3 - , Ca 2+ and SO 4 2− solutions at high PCO 2 . • A new equation calculates electrostricted water (mol/kgw) from hydration number. • CO 2 solubility strongly correlates (R 2  = 0.96) to electrostricted water. • Ion electrostriction of water limits its availability for CO 2 caging and solvation. • Correlations predict CO 2 solubility of several mixed brines to within 1–9%.

  20. Co-Au core-shell nanocrystals formed by sequential ion implantation into SiO2

    International Nuclear Information System (INIS)

    Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S. G.; Foran, G. J.; Ridgway, M. C.

    2006-01-01

    Co-Au core-shell nanocrystals (NCs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . The NCs were investigated by means of transmission electron microscopy and extended x-ray absorption fine structure spectroscopy. The latter reveals a bond length expansion in the Co core compared to monatomic Co NCs. Concomitantly, a significant contraction of the bond length and a significant reduction of the effective Au-Au coordination number were observed in the Au shells. Increased Debye-Waller factors indicate significant strain in the NCs. These experimental results verify recent theoretical predictions

  1. Effect of Co2+ and Y3+ ions insertion on the microstructure development and magnetic properties of Ni0.5Zn0.5Fe2O4 powders synthesized using Co-precipitation method

    Science.gov (United States)

    Rashad, M. M.; Rayan, D. A.; Turky, A. O.; Hessien, M. M.

    2015-01-01

    Nanocrystalline Ni0.5Zn0.5-xCoxFe2-zYzO4 powders (x=0-0.3 and z from 0 to 0.3) have been synthesized via a facile co-precipitation technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) are utilized in order to study the effect of variation of cobalt and yttrium substitutions and its impact on crystalline size, lattice parameter, X-ray density, microstructure and magnetic properties of the formed powders. X-ray diffraction data indicated that, after doping, all samples consisted of the main spinel phase for the formed precursors precipitated at pH 10 annealed at 1000 oC for 2 h. The lattice parameter and the unit cell were decreased linearly with increasing Co content whereas they were increased with increasing the Y incorporation. Additionally, the porosity was increased with increasing Co concentration while it was decreased with increasing the Y insertion. The mean ionic radii and hopping and bond lengths was decreased with the value of Co2+ and they were increased with the value of Y3+ ion as well as both of Y3+ and Co2+ ions. The microstructures of the produced powders were found to be cubic like structure. The addition of Y3+ ion suppressed the grain size whereas addition of Co2+ ion enhanced the grain growth availably. An examination of the magnetic properties revealed an increase in saturation magnetization with increasing Co and Y concentrations incorporation up to x=0.3. Meanwhile, the formed powders exhibited superparamagnetic characteristics. A high saturation magnetization (77.0 emu/g) was achieved for Ni0.5Zn0.2Co0.3Fe2O4 sample annealed at 1000 oC for 2 h.

  2. Synergistic effects of iodine and silver ions co-implanted in 6H–SiC

    International Nuclear Information System (INIS)

    Kuhudzai, R.J.; Malherbe, J.B.; Hlatshwayo, T.T.; Berg, N.G. van der; Devaraj, A.; Zhu, Z.; Nandasiri, M.

    2015-01-01

    Motivated by the aim of understanding the release of fission products through the SiC coating of fuel kernels in modern high temperature nuclear reactors, a fundamental investigation is conducted to understand the synergistic effects of implanted silver (Ag) and iodine (I) in 6H–SiC. The implantation of the individual species, as well as the co-implantation of 360 keV ions of I and Ag at room temperature in 6H–SiC and their subsequent annealing behaviour has been investigated by Secondary Ion Mass Spectrometry (SIMS), Atom Probe Tomography (APT) and X-ray Photoelectron Spectroscopy (XPS). SIMS and APT measurements indicated the presence of Ag in the co-implanted samples after annealing at 1500 °C for 30 h in sharp contrast to the samples implanted with Ag only. In samples implanted with Ag only, complete loss of the implanted Ag was observed. However, for I only implanted samples, some iodine was retained. APT of annealed co-implanted 6H–SiC showed clear spatial association of Ag and I clusters in SiC, which can be attributed to the observed I assisted retention of Ag after annealing. Such detailed studies will be necessary to identify the fundamental mechanism of fission products migration through SiC coatings. - Highlights: • Co-implantation of Ag and I ions in 6H–SiC was performed. • Clear spatial association of Ag and I clusters observed after annealing. • Complete loss of Ag after high temperature annealing of silver only sample. • Iodine was retained in iodine only sample after high temperature annealing. • Iodine was found to play a role in the retention of Ag in the co-implanted samples.

  3. Advanced technology development reducing CO2 emissions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sup

    2010-09-15

    Responding to Korean government policies on green growth and global energy/ environmental challenges, SK energy has been developing new technologies to reduce CO2 emissions by 1) CO2 capture and utilization, 2) efficiency improvement, and 3) Li-ion batteries. The paper introduces three advanced technologies developed by SK energy; GreenPol, ACO, and Li-ion battery. Contributing to company vision, a more energy and less CO2, the three technologies are characterized as follows. GreenPol utilizes CO2 as a feedstock for making polymer. Advanced Catalytic Olefin (ACO) reduces CO2 emission by 20% and increase olefin production by 17%. Li-ion Batteries for automotive industries improves CO2 emission.

  4. Ion implantation induced conducting nano-cluster formation in PPO

    International Nuclear Information System (INIS)

    Das, A.; Patnaik, A.; Ghosh, G.; Dhara, S.

    1997-01-01

    Conversion of polymers and non-polymeric organic molecules from insulating to semiconducting materials as an effect of energetic ion implantation is an established fact. Formation of nano-clusters enriched with carbonaceous materials are made responsible for the insulator-semiconductor transition. Conduction in these implanted materials is observed to follow variable range hopping (VRH) mechanism. Poly(2,6-dimethyl phenylene oxide) [PPO] compatible in various proportion with polystyrene is used as a high thermal resistant insulating polymer. PPO has been used for the first time in the ion implantation study

  5. Uniform deposition of size-selected clusters using Lissajous scanning

    International Nuclear Information System (INIS)

    Beniya, Atsushi; Watanabe, Yoshihide; Hirata, Hirohito

    2016-01-01

    Size-selected clusters can be deposited on the surface using size-selected cluster ion beams. However, because of the cross-sectional intensity distribution of the ion beam, it is difficult to define the coverage of the deposited clusters. The aggregation probability of the cluster depends on coverage, whereas cluster size on the surface depends on the position, despite the size-selected clusters are deposited. It is crucial, therefore, to deposit clusters uniformly on the surface. In this study, size-selected clusters were deposited uniformly on surfaces by scanning the cluster ions in the form of Lissajous pattern. Two sets of deflector electrodes set in orthogonal directions were placed in front of the sample surface. Triangular waves were applied to the electrodes with an irrational frequency ratio to ensure that the ion trajectory filled the sample surface. The advantages of this method are simplicity and low cost of setup compared with raster scanning method. The authors further investigated CO adsorption on size-selected Pt n (n = 7, 15, 20) clusters uniformly deposited on the Al 2 O 3 /NiAl(110) surface and demonstrated the importance of uniform deposition.

  6. Uniform deposition of size-selected clusters using Lissajous scanning

    Energy Technology Data Exchange (ETDEWEB)

    Beniya, Atsushi; Watanabe, Yoshihide, E-mail: e0827@mosk.tytlabs.co.jp [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Hirata, Hirohito [Toyota Motor Corporation, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan)

    2016-05-15

    Size-selected clusters can be deposited on the surface using size-selected cluster ion beams. However, because of the cross-sectional intensity distribution of the ion beam, it is difficult to define the coverage of the deposited clusters. The aggregation probability of the cluster depends on coverage, whereas cluster size on the surface depends on the position, despite the size-selected clusters are deposited. It is crucial, therefore, to deposit clusters uniformly on the surface. In this study, size-selected clusters were deposited uniformly on surfaces by scanning the cluster ions in the form of Lissajous pattern. Two sets of deflector electrodes set in orthogonal directions were placed in front of the sample surface. Triangular waves were applied to the electrodes with an irrational frequency ratio to ensure that the ion trajectory filled the sample surface. The advantages of this method are simplicity and low cost of setup compared with raster scanning method. The authors further investigated CO adsorption on size-selected Pt{sub n} (n = 7, 15, 20) clusters uniformly deposited on the Al{sub 2}O{sub 3}/NiAl(110) surface and demonstrated the importance of uniform deposition.

  7. Glassy behavior in the layered perovskites La2−xSrxCoO4(1.1≤x≤1.3)

    International Nuclear Information System (INIS)

    Mukherjee, S.; Mukherjee, Rajarshi; Banerjee, S.; Ranganathan, R.; Kumar, Uday

    2012-01-01

    The glassy behavior of the phase segregated state in the layered cobaltite La 2−x Sr x CoO 4 has been studied. The role of the inter-cluster interactions as well as the disordered spins at the paramagnetic–ferromagnetic interface, behind the observed glassy behavior have been investigated. The disordered spins at the interface appear to be strongly pinned, and they contribute little to the observed glassy behavior. On the other hand, the inter-cluster interactions play the key role. Both the Co 4+ and Co 3+ ions are in the intermediate spin state. - Highlights: ► Phase segregated state of cobaltite La 2−x Sr x CoO 4 for (1.1≤x≤1.3) to find the origin of the observed glassy behavior. ► Result of the frequency dependent ac susceptibility measurement excludes the possibility of any spin glass phase, hints strong inter-cluster interactions. ► Relaxation experiments confirm the system to be a collection of clusters with two preferred sizes. ► The glassy behavior originates from strong inter-cluster interactions.

  8. Improvement of the cycling performance of LiCoO2 with assistance of cross-linked PAN for lithium ion batteries

    International Nuclear Information System (INIS)

    Yang, Xinhe; Shen, Lanyao; Wu, Bin; Zuo, Zicheng; Mu, Daobin; Wu, Borong; Zhou, Henghui

    2015-01-01

    Highlights: • Cross-linked PAN coating was prepared without damaging the surface of LiCoO 2 . • The coating layer owns good electronic conductivity and mechanical strength. • The cross-linked PAN coating layer is more sufficient than Al 2 O 3 coating. • It shows much improved cyclability than that of bare and Al 2 O 3 coated LiCoO 2 . - Abstract: LiCoO 2 has been widely used in lithium ion batteries for digital electronic products. However, the limited cycling performance under high cut-off voltage hinders its commercial application. Many metal oxides and/or phosphorus coating have been reported to improve the cycling performance of LiCoO 2 . In this paper, we report on cross-linked PAN coated LiCoO 2 composite as a cathode material for lithium ion batteries. The coating layer was obtained by intermolecular crosslinking of PAN polymer chain by heat treatment at high temperature in air. The air heating process avoids the possible damage arising from the carbon thermal reduction to the surface structure of LiCoO 2 . Electrochemical test indicates that the LiCoO 2 with the cross-linked PAN coating layer shows much improved cycle performance compared with that of bare and Al 2 O 3 coated LiCoO 2 . These findings might also open new avenues to explore polymer coating for other cathode materials of lithium ion batteries

  9. Magnetic and Moessbauer studies on GdCo3B2 and DyCo3B2

    International Nuclear Information System (INIS)

    Malik, S.K.; Umarji, A.M.; Shenoy, G.K.

    1984-10-01

    Magnetization and Moessbauer studies have been carried out on GdCo 3 B 2 and DyCo 3 B 2 . These compounds are magnetically ordered with Curie temperatures of 56 0 and 21 0 K respectively. The Co atoms are either nonmagnetic or carry a small moment in these compounds. The saturation moment of DyCo 3 B 2 at 5 0 K is smaller than the Dy 3+ free-ion value. From 161 Dy Moessbauer studies, the measured hyperfine magnetic field at the Dy site is also observed to be smaller than the free-ion value. 155 Gd Moessbauer measurements in GdCo 3 B 2 reveal the presence of large crystalline electric fields at the rare earth site. This causes the moment and the hyperfine field at the Dy site in DyCo 3 B 2 to be reduced from its free-ion value

  10. Observations on small anionic clusters in an electrostatic ion beam trap

    International Nuclear Information System (INIS)

    Eritt, Markus

    2008-01-01

    The term atomic cluster relates to compounds of at least two or three atoms. Thereby the physical properties are size dependent and the property transitions between single atoms and bulk material are not always smooth. Ion traps allow it to observe internal cluster properties independent from the influence of external forces. In this work the electron induced decay of singly negatively charged atomic clusters was observed. The dissociation cross section of the clusters is dominated by detachment of the only weakly bound outer electrons. For simple atoms at low electron energies a simple scaling law can be obtained that includes only the binding energies of the valence electrons. Nevertheless for larger sizes theoretical calculations predict so called ''giant resonances'' as dominant decay process in metal clusters. Due to mass limitations in storage rings exist so far only cross section measurements for simple anions and small negative molecules. In this work the electron detachment cross sections of small negatively charged carbon (C n - n=2-12), aluminium (Al n - n=2-7) and silver clusters (Ag n - n=1-11) were measured in an electrostatic ion beam trap. The classical scaling law, including only the binding energies of the valence electrons, turned out to be not sufficient, especially for larger clusters. In order to improve the correlation between measured and predicted values it was proposed to involve the influence of the cluster volume and the specific polarisability induced by long range coulomb interaction. For silver clusters the best agreement was obtained using a combination of the projected area reduced by the polarisability. The existence of ''giant resonances'' could not be confirmed. According to theory for clusters with a broad internal energy distribution, a power-law decay close to 1/time is expected. For some clusters the lifetime behaviour would be strongly quenched by photon emission. The thermionic evaporative decay of anionic aluminium and

  11. CoSi2 growth on Si(001) by reactive deposition epitaxy: Effects of high-flux, low-energy ion irradiation

    International Nuclear Information System (INIS)

    Lim, C. W.; Greene, J. E.; Petrov, I.

    2006-01-01

    CoSi 2 layers, CoSi 2 (parallel sign)(001) Si and [100] CoSi 2 (parallel sign)[100] Si , contain fourfold symmetric (111) twinned domains oriented such that (221) CoSi 2 (parallel sign)(001) Si and CoSi 2 (parallel sign)[110] Si . We demonstrate that high-flux low-energy (E Ar + =9.6 eV) Ar + ion irradiation during deposition dramatically increases the area fraction f u of untwinned regions from 0.17 in films grown under standard magnetically balanced conditions in which the ratio J Ar + /J Co of the incident Ar + to Co fluxes is 1.4 to 0.72 with J Ar + /J Co =13.3. TEM analyses show that the early stages of RDE CoSi 2 (001) film growth proceed via the Volmer-Weber mode with independent nucleation of both untwinned and twinned islands. Increasing J Ar + /J Co results in larger values of both the number density and area of untwinned with respect to twinned islands. The intense Ar + ion bombardment creates additional low-energy adsorption sites that favor the nucleation of untwinned islands while collisionally enhancing Co surface mobilities which, in turn, increases the probability of itinerant Co adatoms reaching these sites

  12. Structural Characterizations of Palladium Clusters Prepared by Polyol Reduction of [PdCl4]2Ions

    Directory of Open Access Journals (Sweden)

    Loredana Schiavo

    2016-01-01

    Full Text Available Palladium nanoparticles are of great interest in many industrial fields, ranging from catalysis and hydrogen technology to microelectronics, thanks to their unique physical and chemical properties. In this work, palladium clusters have been prepared by reduction of [PdCl4]2ions with ethylene glycol, in the presence of poly(N-vinyl-2-pyrrolidone (PVP as stabilizer. The stabilizer performs the important role of nucleating agent for the Pd atoms with a fast phase separation, since palladium atoms coordinated to the polymer side-groups are forced at short distances during nucleation. Quasispherical palladium clusters with a diameter of ca. 2.6 nm were obtained by reaction in air at 90°C for 2 hours. An extensive materials characterization by transmission electron microscopy (TEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, and other characterizations (TGA, SEM, EDS-SEM, and UV-Vis has been performed in order to evaluate the structure and oxidation state of nanopalladium.

  13. Observations of CO and OI in stars in globular clusters

    International Nuclear Information System (INIS)

    Wallerstein, G.; Pilachowski, C.

    1978-01-01

    Since studies at classification dispersion and early analyses of high dispersion spectra have yielded little quantitative data on the abundances of C, N, and O in globular clusters the authors have been endeavoring to establish their abundances in stars in several clusters. The problem has been approached in two ways, by observing the 2.3 micron CO bands and the 6300 A [OI] line in individual stars in globular clusters. (Auth.)

  14. Physicochemical properties of synthetic nano-birnessite and its enhanced scavenging of Co"2"+ and Sr"2"+ ions from aqueous solutions

    International Nuclear Information System (INIS)

    Metwally, S.S.; Ghaly, M.; El-Sherief, E.A.

    2017-01-01

    Nano-birnessite was prepared, characterized and used for removal of cobalt and strontium ions from aqueous solutions. Scanning electron microscope and atomic force microscope images indicated that the particles of the prepared material are presented in the nano-scale form, the grain size was found in a range of 58–95 nm. Specific surface area of the prepared nano-birnessite was determined and found to be 200.54 m"2/g. The Capacities of nano-birnessite for cobalt and strontium are 2.97 and 3.04 meq/g, respectively. The kinetic studies indicated that the sorption of the two ions obeys pseudo-second-order model and controlled by an intra-particle diffusion mechanism. The diffusivity of Co"2"+ and Sr"2"+ ions onto nano-birnessite was determined and indicated that the sorption is chemisorption process. Hence, nano-birnessite material is an efficient sorbent and can be used to decrease the influx of pollutants, such as; Co"2"+ and Sr"2"+ ions to the environment or their removal from contaminated media. - Graphical abstract: 3D AFM images for nano-birnessite. - Highlights: • Nano-birnessite was prepared using sol-gel method. • It was characterized using different analytical techniques. • Sorption of cobalt and strontium ions onto nano-birnessite was investigated. • Kinetic studies and some kinetic models were tested for the sorption process. • Nano-birnessite exhibited high sorption capacity compared to other sorbents obtained in the literature.

  15. LiCoO/sub 2/ structures by spray pyrolysis technique for rechargeable Li-ion battery

    International Nuclear Information System (INIS)

    Yilmaz, M.; Turgut, G.; Aydin, S.; Ertugrul, M.

    2012-01-01

    As the lithium-ion batteries have high energy density, Lithium-batteries have become a very attractive field of study for the researchers. Batteries' high energy density is up to the anode and cathode materials used in the batteries and the technique which is chosen for getting these materials. In this study, LiCoO/sub 2/, used for cathode active material in lithium ion batteries, has been prepared with spraying on a glass base by spray pyrolysis technique. LiCoO/sub 2 /was annealed at 600 deg. C for 3h in an air atmosphere; and crystal structures of the obtained samples were examined with XRD, the surface morphology of them was examined with SEM. Effect of annealing on crystallization has been investigated in prepared samples. (author)

  16. Enhancing visible light photocatalytic and photocharge separation of (BiO){sub 2}CO{sub 3} plate via dramatic I{sup −} ions doping effect

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Lei [College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, Anhui (China); Cao, Jing [College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, Anhui (China); Anhui Collaborative Innovation Center of Advanced Functional Composite, Huaibei, 235000, Anhui (China); Lin, Haili, E-mail: linhaili@mail.ipc.ac.cn [College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, Anhui (China); Guo, Xiaomin; Zhang, Meiyu [College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, Anhui (China); Chen, Shifu, E-mail: chshifu@chnu.edu.cn [College of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, Anhui (China); College of Chemistry and Materials Engineering, Anhui Science and Technology University, Fengyang, 233100, Anhui (China)

    2016-08-15

    Highlights: • Novel I-(BiO){sub 2}CO{sub 3} was prepared by a facile chemical precipitation method. • I{sup −} ions impurity level located on the top of valence band of (BiO){sub 2}CO{sub 3}. • I{sup −} ions doping largely improved photocatalytic activity of I-(BiO){sub 2}CO{sub 3}. • I-(BiO){sub 2}CO{sub 3} displayed excellent photocharge separation efficiency. - Abstract: Novel I{sup −} ions doped (BiO){sub 2}CO{sub 3} (I-(BiO){sub 2}CO{sub 3}) photocatalysts were successfully synthesized via a facile chemical precipitation method. Under visible light (λ > 400 nm), I-(BiO){sub 2}CO{sub 3} displayed much higher activity for rhodamine B and dichlorophenol degradation than the undoped (BiO){sub 2}CO{sub 3}. The pseudo-first-order rate constant k{sub app} of RhB degradation over 15.0% I-(BiO){sub 2}CO{sub 3} was 0.54 h{sup −1}, which is 11.3 times higher than that of (BiO){sub 2}CO{sub 3}. The doped I{sup −} ions formed an impurity level on the top of valence band of (BiO){sub 2}CO{sub 3} and induced much more visible light to be absorbed. The enhanced photocurrent and surface photovoltage properties were detected, which strongly ensures the efficient separation of electrons and holes in I-(BiO){sub 2}CO{sub 3} system under visible light. It provides a facile way to improve the photocatalytic activity of the wide-band-gap (BiO){sub 2}CO{sub 3} via intense doping effect of I{sup −} ions.

  17. blockcluster: An R Package for Model-Based Co-Clustering

    Directory of Open Access Journals (Sweden)

    Parmeet Singh Bhatia

    2017-02-01

    Full Text Available Simultaneous clustering of rows and columns, usually designated by bi-clustering, coclustering or block clustering, is an important technique in two way data analysis. A new standard and efficient approach has been recently proposed based on the latent block model (Govaert and Nadif 2003 which takes into account the block clustering problem on both the individual and variable sets. This article presents our R package blockcluster for co-clustering of binary, contingency and continuous data based on these very models. In this document, we will give a brief review of the model-based block clustering methods, and we will show how the R package blockcluster can be used for co-clustering.

  18. Controlled phase stability of highly Na-active triclinic structure in nanoscale high-voltage Na2-2xCo1+xP2O7 cathode for Na-ion batteries

    Science.gov (United States)

    Song, Hee Jo; Kim, Jae-Chan; Dar, Mushtaq Ahmad; Kim, Dong-Wan

    2018-02-01

    With the increasing demand for high energy density in energy-storage systems, a high-voltage cathode is essential in rechargeable Li-ion and Na-ion batteries. The operating voltage of a triclinic-polymorph Na2CoP2O7, also known as the rose form, is above 4.0 V (vs. Na/Na+), which is relatively high compared to that of other cathode materials. Thus, it can be employed as a potential high-voltage cathode material in Na-ion batteries. However, it is difficult to synthesize a pure rose phase because of its low phase stability, thus limiting its use in high-voltage applications. Herein, compositional-engineered, rose-phase Na2-2xCo1+xP2O7/C (x = 0, 0.1 and 0.2) nanopowder are prepared using a wet-chemical method. The Na2-2xCo1+xP2O7/C cathode shows high electrochemical reactivity with Na ions at 4.0 V, delivering high capacity and high energy density.

  19. Li ion transport in sputter deposited LiCoO{sub 2} thin films and glassy borate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stockhoff, Tobias; Gallasch, Tobias; Schmitz, Guido [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Materialphysik, Muenster (Germany)

    2010-07-01

    LiCoO{sub 2} membranes are key components of current battery technology. We investigate sputter-deposited thin films of these materials aiming at the application in all-solid-state thin film batteries. For this, LiCoO{sub 2} films (10-200 nm) were deposited onto ITO-coated glass substrates by ion beam sputtering. In addition, a part of these films are coated by an ion-conductive membrane of Li{sub 2}O-B{sub 2}O{sub 3} glasses in the thickness range of 50 to 300 nm. Structural, chemical and electrical properties of the layers are studied by means of TEM(EELS) and various electrical methods (cyclic voltammetry, chrono-amperometry/-potentiometry). Since the color of the LiCoO{sub 2} films changes from red-brown to grey during de-intercalation of Li and the substrate as well as the glassy membrane deposited on top are optical transparent, reversible Li de- and intercalation can be directly demonstrated and quantified by a measurement of light transmission through the layered system. Samples coated with an ion-conductive membrane reveal a characteristic delay in switching optical transparency which is due to the slower transport across the membrane. Varying the thickness of the glassy membrane, the d.c. ion-conductivity and permeation through the membrane is determined quantitatively. Using thin membranes in the range of a few tens of nanometers the critical current densities are way sufficient for battery applications.

  20. Reversible inactivation of CO dehydrogenase with thiol compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kreß, Oliver [Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany); Gnida, Manuel [Department of Chemistry, University of Paderborn, 33098 Paderborn (Germany); Pelzmann, Astrid M. [Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany); Marx, Christian [Institute of Biochemistry and Biophysics, Friedrich-Schiller-University of Jena, 07745 Jena (Germany); Meyer-Klaucke, Wolfram [Department of Chemistry, University of Paderborn, 33098 Paderborn (Germany); Meyer, Ortwin, E-mail: Ortwin.Meyer@uni-bayreuth.de [Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany)

    2014-05-09

    Highlights: • Rather large thiols (e.g. coenzyme A) can reach the active site of CO dehydrogenase. • CO- and H{sub 2}-oxidizing activity of CO dehydrogenase is inhibited by thiols. • Inhibition by thiols was reversed by CO or upon lowering the thiol concentration. • Thiols coordinate the Cu ion in the [CuSMo(=O)OH] active site as a third ligand. - Abstract: Carbon monoxide dehydrogenase (CO dehydrogenase) from Oligotropha carboxidovorans is a structurally characterized member of the molybdenum hydroxylase enzyme family. It catalyzes the oxidation of CO (CO + H{sub 2}O → CO{sub 2} + 2e{sup −} + 2H{sup +}) which proceeds at a unique [CuSMo(=O)OH] metal cluster. Because of changing activities of CO dehydrogenase, particularly in subcellular fractions, we speculated whether the enzyme would be subject to regulation by thiols (RSH). Here we establish inhibition of CO dehydrogenase by thiols and report the corresponding K{sub i}-values (mM): L-cysteine (5.2), D-cysteine (9.7), N-acetyl-L-cysteine (8.2), D,L-homocysteine (25.8), L-cysteine–glycine (2.0), dithiothreitol (4.1), coenzyme A (8.3), and 2-mercaptoethanol (9.3). Inhibition of the enzyme was reversed by CO or upon lowering the thiol concentration. Electron paramagnetic resonance spectroscopy (EPR) and X-ray absorption spectroscopy (XAS) of thiol-inhibited CO dehydrogenase revealed a bimetallic site in which the RSH coordinates to the Cu-ion as a third ligand ([Mo{sup VI}(=O)OH{sub (2)}SCu{sup I}(SR)S-Cys]) leaving the redox state of the Cu(I) and the Mo(VI) unchanged. Collectively, our findings establish a regulation of CO dehydrogenase activity by thiols in vitro. They also corroborate the hypothesis that CO interacts with the Cu-ion first. The result that thiol compounds much larger than CO can freely travel through the substrate channel leading to the bimetallic cluster challenges previous concepts involving chaperone function and is of importance for an understanding how the sulfuration step in

  1. Hydrogen constituents of the mesosphere inferred from positive ions - H2O, CH4, H2CO, H2O2, and HCN

    Science.gov (United States)

    Kopp, E.

    1990-01-01

    The concentrations in the mesosphere of H2O, CH4, H2CO, H2O2, and HCN were inferred from data on positive ion compositions, obtained from one mid-latitude and four high-latitude rocket flights. The inferred concentrations were found to agree only partially with the ground-based microwave measurements and/or model prediction by Garcia and Solomon (1985). The CH4 concentration was found to vary between 70 and 4 ppb in daytime and 900 and 100 ppbv at night, respectively. Unexpectedly high H2CO concentrations were obtained, with H2CO/H2O ratios between 0.0006 and 0.1, and a mean HCN volume mixing ratio of 6 x 10 to the -10th was inferred.

  2. Investigation of modulus hardening of various co-clusters in aged Al-Cu-Mg-Ag alloy by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Song [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiyi, E-mail: liuzhiyi@csu.edu.cn [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Ying, Puyou; Wang, Jian; Li, Junlin [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China)

    2016-06-21

    The modulus hardening capability of various co-clusters in a low Cu/Mg ratio Al-Cu-Mg-Ag alloy aged at 165 °C is investigated by quantitative atom probe tomography analysis. Prolonged aging from 5 min to 2 h leads to the simultaneous increase in the critical shear stress of both Mg-Ag and Cu-Mg co-clusters. Regardless of the higher shear modulus of Cu-Mg co-clusters, calculation results show that Mg-Ag co-clusters possess a greater modulus hardening capability than Cu-Mg co-clusters, suggesting its primary contribution to the rapid hardening at the early aging stage. As aging extends from 30 min to 2 h, the increment in the critical shear stress of Mg-Ag co-clusters is lower than that of Cu-Mg co-clusters due to the precipitation of high density Ω phase. In addition, the shear modulus of Mg-Ag co-clusters is generally independent on its size at each investigated condition.

  3. Investigation of modulus hardening of various co-clusters in aged Al-Cu-Mg-Ag alloy by atom probe tomography

    International Nuclear Information System (INIS)

    Bai, Song; Liu, Zhiyi; Ying, Puyou; Wang, Jian; Li, Junlin

    2016-01-01

    The modulus hardening capability of various co-clusters in a low Cu/Mg ratio Al-Cu-Mg-Ag alloy aged at 165 °C is investigated by quantitative atom probe tomography analysis. Prolonged aging from 5 min to 2 h leads to the simultaneous increase in the critical shear stress of both Mg-Ag and Cu-Mg co-clusters. Regardless of the higher shear modulus of Cu-Mg co-clusters, calculation results show that Mg-Ag co-clusters possess a greater modulus hardening capability than Cu-Mg co-clusters, suggesting its primary contribution to the rapid hardening at the early aging stage. As aging extends from 30 min to 2 h, the increment in the critical shear stress of Mg-Ag co-clusters is lower than that of Cu-Mg co-clusters due to the precipitation of high density Ω phase. In addition, the shear modulus of Mg-Ag co-clusters is generally independent on its size at each investigated condition.

  4. Relaxation effects in ionic mobility and cluster formation: negative ions in SF6 at high pressures

    International Nuclear Information System (INIS)

    Juarez, A M; De Urquijo, J; Hinojosa, G; Hernandez-Avila, J L; Basurto, E

    2010-01-01

    The relaxation effects of the ionic mobility and the formation of negative-ion clusters in SF 6 are studied in this work. For this purpose, we have measured the mobility of negative ions in SF 6 over the pressure range 100-800 Torr at a fixed value of density-normalized electric field, E/N, of 20 Td (1 Townsend = 10 -17 V cm 2 ). The data obtained show a clear dependence of the negative-ion drift velocity on drift distance. It is observed that the drift velocity (mobility) reaches a steady-state value only for drift distances above 2 cm, over the studied pressure range. In addition to this, we have observed that the ionic mobility depends strongly on the gas pressure. An explanation of this dependence of the ionic mobility on gas pressure is given in terms of a negative-ion clustering formation process. It was found that the assumption of a linear dependence of the cluster ion mass on pressure provides a satisfactory explanation for the observed mobilities.

  5. Interaction of multicharged ions with molecules (CO{sub 2}, C{sub 60}) by coincident electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Universite Paul Sabatier, Toulouse (France). Lab. CAR-IRSAMC

    2001-07-01

    First results for the investigation of electron capture processes in collisions between multicharged ions and molecule targets using electron spectroscopy in coincidence with charged fragments, are presented. It is shown that a much more detailed investigation of the capture reaction can be achieved using molecular instead of heavy atomic targets provided that an analysis of the target dissociation is made. The collisional systems {sup 18}O{sup 8+}+Ar, CO{sub 2} and C{sub 60} have been studied at 80 keV. Non coincident electron spectra as well as first results of double or triple coincidence experiments are discussed. Kinetic energy distributions of the C{sub n}{sup +} fragments (n=1 to 8) produced in multiple capture processes from C{sub 60} target are given. A detailed investigation of the double capture process with CO{sub 2} molecule allows the measurement of kinetic energy release distributions (KERD) which characterize the dissociation of CO{sub 2}{sup 2+} molecular ions; our results are found to be very similar to those measured in double photoionisation experiments. (orig.)

  6. Angular distributions of particles sputtered from multicomponent targets with gas cluster ions

    Energy Technology Data Exchange (ETDEWEB)

    Ieshkin, A.E. [Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Ermakov, Yu.A., E-mail: yuriermak@yandex.ru [Skobeltsyn Nuclear Physics Research Institute, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Chernysh, V.S. [Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation)

    2015-07-01

    The experimental angular distributions of atoms sputtered from polycrystalline W, Cd and Ni based alloys with 10 keV Ar cluster ions are presented. RBS was used to analyze a material deposited on a collector. It has been found that the mechanism of sputtering, connected with elastic properties of materials, has a significant influence on the angular distributions of sputtered components. The effect of non-stoichiometric sputtering at different emission angles has been found for the alloys under cluster ion bombardment. Substantial smoothing of the surface relief was observed for all targets irradiated with cluster ions.

  7. Temperature-Dependent Evolution of the Oxidation States of Cobalt and Platinum in Co 1–x Pt x Clusters under H 2 and CO + H 2 Atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bing; Khadra, Ghassan; Tuaillon-Combes, Juliette; Tyo, Eric C.; Pellin, Michael J.; Reinhart, Benjamin; Seifert, Sönke; Chen, Xinqi; Dupuis, Veronique; Vajda, Stefan

    2016-09-29

    Co1-xPtx clusters of 2.9-nm size with a range of atomically precise Pt/Co atomic ratios (x = 0, 0.25, 0.5, 0.75, 1) were synthesized using the mass-selected low-energy cluster beam deposition (LECBD) technique and soft-landed onto an amorphous alumina thin film prepared by atomic layer deposition (ALD). Utilizing ex situ X-ray photoemission spectroscopy (XPS), the oxidation state of the as-made clusters supported on Al2O3 was determined after both a 1-h-long exposure to air and aging for several weeks while exposed to air. Next, the aged duster samples were characterized by grazing-incidence X-ray absorption spectroscopy (GIXAS) and then pretreated with diluted hydrogen and further exposed to the mixture of diluted CO and H-2 up to 225 degrees C at atmospheric pressure, and the temperature-dependent evolutions of the particle size/shape and the oxidation states of the individual metal components within the dusters were monitored using in situ grazing-incidence small-angle X-ray scattering and X-ray absorption spectroscopy (GISAXS/GIXAS). The changes in the oxidation states of Co and Pt exhibited a nonlinear dependence on the Pt/Co atomic ratio of the dusters. For example, a low Pt/Co ratio (x <= 0.5) facilitates the formation of Co(OH)(2), whereas a high Pt/Co ratio (x = 0.75) stabilizes the Co3O4 composition instead through the formation of a Co-Pt core-shell structure where the platinum shell inhibits the reduction of cobalt in the core of the Co1-xPtx alloy dusters. The obtained results indicate methods for optimizing the composition and structure of binary alloy clusters for catalysis.

  8. Confined SnO2 quantum-dot clusters in graphene sheets as high-performance anodes for lithium-ion batteries

    OpenAIRE

    Zhu, Chengling; Zhu, Shenmin; Zhang, Kai; Hui, Zeyu; Pan, Hui; Chen, Zhixin; Li, Yao; Zhang, Di; Wang, Da-Wei

    2016-01-01

    Construction of metal oxide nanoparticles as anodes is of special interest for next-generation lithium-ion batteries. The main challenge lies in their rapid capacity fading caused by the structural degradation and instability of solid-electrolyte interphase (SEI) layer during charge/discharge process. Herein, we address these problems by constructing a novel-structured SnO2-based anode. The novel structure consists of mesoporous clusters of SnO2 quantum dots (SnO2 QDs), which are wrapped with...

  9. Liquid-Solid-Solution Assembly of CoFe2O4/Graphene Nanocomposite as a High-Performance Lithium-Ion Battery Anode

    International Nuclear Information System (INIS)

    Zhu, Yanfang; Lv, Xingbin; Zhang, Lili; Guo, Xiaodong; Liu, Daijun; Chen, Jianjun; Ji, Junyi

    2016-01-01

    Graphical abstract: CoFe 2 O 4 /rGO composites are fabricated via a liquid-solid-solution assemble strategy with a well controlled CoFe 2 O 4 size, the composite exhibits a high rate performance for lithium ion batteries anode. - Highlights: • Crumpled CoFe 2 O 4 @graphene composite with uniform CoFe 2 O 4 nanoparticles intimately anchored on graphene sheets was fabricated. • The novel fabrication strategy: liquid-solid-solution strategy where the CoFe 2 O 4 are nucleation and controlled growth at the oil/water interface. • High reversible specific capacity of 1102 mAh g −1 after 100 cycles and high rate capability of 410 mAh g −1 within 230 s charging. - Abstract: CoFe 2 O 4 /graphene composites were fabricated via a novel one-pot liquid-solid-solution (LSS) hydrothermal process. Through ions electrostatic adsorption onto graphene sheets and oil microemulsion encapsulation, CoFe 2 O 4 nanoparticles can be uniformly anchored on crumpled graphene sheets without aggregation, and the size distribution of CoFe 2 O 4 particles can be controlled by the microemulsion shell in the range of 50–100 nm. With the synergistic effect between CoFe 2 O 4 and graphene, the CoFe 2 O 4 /graphene hybrid exhibits a high reversible specific capacity of 1102 mAh g −1 at 0.2 A g −1 after 100 cycles, and a good cycling stability as well. Moreover, the composite has good rate capability. The specific capacity can reach a high value of 410 mAh g −1 even under a high current density of 6.4 A g −1 (corresponds to a charge time of ∼230 s), indicating its promising application as an anode material for lithium ion batteries.

  10. Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar"+ ions

    International Nuclear Information System (INIS)

    Okunev, V.D.; Samoilenko, Z.A.; Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S.J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J.; Wolny-Marszałek, M.; Jeżabek, M.; Varyukhin, V.N.; Antoshina, I.A.

    2016-01-01

    We show that cluster magnetism in ferromagnetic amorphous Fe_6_7Cr_1_8B_1_5 alloy is related to the presence of large, D=150–250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30–100 Å, α-(Fe, Cr) and Fe_3B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10–20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×10"1"8 ions/cm"2) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×10"1"8 ions/cm"2, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T)~T"2 is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×10"1"8 ions/cm"2, the transition to a dependence ρ(T)~T"1"/"2 is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×10"1"8 ions/cm"2, a return to the dependence ρ(T)~T"2 is observed. - Highlights: • The samples at high dose of ion irradiation become more homogeneous. • Gigantic increase in density of the samples (twice as much) is observed. • Ferromagnetism in large Fe–Cr clusters is restored. • Ferromagnetism of Fe–Cr clusters suppresses local superconductivity in them. • The participation of quantum defects in scattering of electrons is returned.

  11. Polar cap ion beams during periods of northward IMF: Cluster statistical results

    Directory of Open Access Journals (Sweden)

    R. Maggiolo

    2011-05-01

    Full Text Available Above the polar caps and during prolonged periods of northward IMF, the Cluster satellites detect upward accelerated ion beams with energies up to a few keV. They are associated with converging electric field structures indicating that the acceleration is caused by a quasi-static field-aligned electric field that can extend to altitudes higher than 7 RE (Maggiolo et al., 2006; Teste et al., 2007. Using the AMDA science analysis service provided by the Centre de Données de la Physique des Plasmas, we have been able to extract about 200 events of accelerated upgoing ion beams above the polar caps from the Cluster database. Most of these observations are taken at altitudes lower than 7 RE and in the Northern Hemisphere. We investigate the statistical properties of these ion beams. We analyze their geometry, the properties of the plasma populations and of the electric field inside and around the beams, as well as their dependence on solar wind and IMF conditions. We show that ~40 % of the ion beams are collocated with a relatively hot and isotropic plasma population. The density and temperature of the isotropic population are highly variable but suggest that this plasma originates from the plasma sheet. The ion beam properties do not change significantly when the isotropic, hot background population is present. Furthermore, during one single polar cap crossing by Cluster it is possible to detect upgoing ion beams both with and without an accompanying isotropic component. The analysis of the variation of the IMF BZ component prior to the detection of the beams indicates that the delay between a northward/southward turning of IMF and the appearance/disappearance of the beams is respectively ~2 h and 20 min. The observed electrodynamic characteristics of high altitude polar cap ion beams suggest that they are closely connected to polar cap auroral arcs. We discuss the implications of these Cluster observations above the polar cap on the magnetospheric

  12. Hierarchical Core/Shell NiCo2O4@NiCo2O4 Nanocactus Arrays with Dual-functionalities for High Performance Supercapacitors and Li-ion Batteries

    Science.gov (United States)

    Cheng, Jinbing; Lu, Yang; Qiu, Kangwen; Yan, Hailong; Xu, Jinyou; Han, Lei; Liu, Xianming; Luo, Jingshan; Kim, Jang-Kyo; Luo, Yongsong

    2015-07-01

    We report the synthesis of three dimensional (3D) NiCo2O4@NiCo2O4 nanocactus arrays grown directly on a Ni current collector using a facile solution method followed by electrodeposition. They possess a unique 3D hierarchical core-shell structure with large surface area and dual-functionalities that can serve as electrodes for both supercapacitors (SCs) and lithium-ion batteries (LIBs). As the SC electrode, they deliver a remarkable specific capacitance of 1264 F g-1 at a current density of 2 A g-1 and ~93.4% of capacitance retention after 5000 cycles at 2 A g-1. When used as the anode for LIBs, a high reversible capacity of 925 mA h g-1 is achieved at a rate of 120 mA g-1 with excellent cyclic stability and rate capability. The ameliorating features of the NiCo2O4 core/shell structure grown directly on highly conductive Ni foam, such as hierarchical mesopores, numerous hairy needles and a large surface area, are responsible for the fast electron/ion transfer and large active sites which commonly contribute to the excellent electrochemical performance of both the SC and LIB electrodes.

  13. Observations on small anionic clusters in an electrostatic ion beam trap

    Energy Technology Data Exchange (ETDEWEB)

    Eritt, Markus

    2008-10-02

    The term atomic cluster relates to compounds of at least two or three atoms. Thereby the physical properties are size dependent and the property transitions between single atoms and bulk material are not always smooth. Ion traps allow it to observe internal cluster properties independent from the influence of external forces. In this work the electron induced decay of singly negatively charged atomic clusters was observed. The dissociation cross section of the clusters is dominated by detachment of the only weakly bound outer electrons. For simple atoms at low electron energies a simple scaling law can be obtained that includes only the binding energies of the valence electrons. Nevertheless for larger sizes theoretical calculations predict so called ''giant resonances'' as dominant decay process in metal clusters. Due to mass limitations in storage rings exist so far only cross section measurements for simple anions and small negative molecules. In this work the electron detachment cross sections of small negatively charged carbon (C{sub n}{sup -} n=2-12), aluminium (Al{sub n}{sup -} n=2-7) and silver clusters (Ag{sub n}{sup -} n=1-11) were measured in an electrostatic ion beam trap. The classical scaling law, including only the binding energies of the valence electrons, turned out to be not sufficient, especially for larger clusters. In order to improve the correlation between measured and predicted values it was proposed to involve the influence of the cluster volume and the specific polarisability induced by long range coulomb interaction. For silver clusters the best agreement was obtained using a combination of the projected area reduced by the polarisability. The existence of ''giant resonances'' could not be confirmed. According to theory for clusters with a broad internal energy distribution, a power-law decay close to 1/time is expected. For some clusters the lifetime behaviour would be strongly quenched by photon

  14. Studies of the coagulation flotation of bentonite and its application to the removal of Co2+ ions and fission products, Ce and Eu

    International Nuclear Information System (INIS)

    Kobayashi, Koichi; Sato, Hiroshi; Kachi, Kosei; Nakamura, Masao; Sasaki, Tsunetaka

    1975-01-01

    The regions of dispersion, coagulation precipitation, coagulation flotation, and redispersion were determined for aqueous bentonite-cationic surfactant and bentonite-cationic surfactant-polyacrylamide(PAA) systems. The region of coagulation flotation was markedly extended by the addition of PAA to both the lower and higher concentration regions of the cationic surfactant, hexadecyldimethylbenzylammonium chloride(HDBAC), and to the lower concentration region of bentonite. The phenomenon of coagulation flotation was investigated in detail and was applied to the removal of Co 2+ ions and nuclear fission products, 144 Ce and 155 Eu, from an aqueous solution. The composition of the reagents for the maximum efficiency of bentonite flotation corresponded to that of the maximum efficiency of Co 2+ -ion flotation. The effect of the pH on the flotation efficiency was studied in particular. The maximum flotation efficiency of 96% was obtained at pH 11 for Co 2+ ions, 86% at pH 9.7 for 144 Ce, and 93% at pH 10.5 for 155 Eu. These radioactive elements were almost completely adsorbed on the surface of bentonite particles and were floated with them in the pH region of the maximum flotation efficiency. It was confirmed that Co 2+ ions could be floated also from an extremely low concentration (10 -9 mol/l) of Co 2+ ions with nearly the same efficiency of flotation and with the additives in the same condition. Co 2+ ions could also be effectively removed by using the step-by-step flotation, showing as high a flotation efficiency as 99.8%. (auth.)

  15. Measurement and Calculation of Absolute Single- and Multiple-Charge-Exchange Cross Sections for Feq+ Ions Impacting CO and CO2

    Energy Technology Data Exchange (ETDEWEB)

    Simcic, J. [Jet Propulsion Laboratory/Caltech; Schultz, David Robert [ORNL; Mawhorter, R. J. [Pomona College; Cadez, I. [Jozef Stefan Institute, Slovenia; Greenwood, J. B. [Queen' s University, Belfast; Chutjian, A. [Jet Propulsion Laboratory/Caltech; Lisse, Carey M. [Johns Hopkins University; Smith, S. J. [Indiana Wesleyan University, Marion

    2010-01-01

    Absolute cross sections are reported for single, double, and triple charge exchange of Feq+ (q=5- 13) ions with CO and CO2. The highly-charged Fe ions are generated in an electron cyclotron resonance ion source. Absolute data are derived from knowledge of the target gas pressure, target path length, and incident and charge-exchanged ion currents. Experimental results are compared with new calculations of these cross sections in the n-electron classical trajectory Monte-Carlo approximation, in which the ensuing radiative and non-radiative cascades are approximated with scaled hydrogenic transition probabilities and scaled Auger rates. The present data are needed in astrophysical applications of solar- and stellar-wind charge-exchange with comets, planetary atmospheres, and circumstellar clouds.

  16. Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi2S4) nanoparticles hybrid anode for high performance lithium ion capacitor.

    Science.gov (United States)

    Jagadale, Ajay; Zhou, Xuan; Blaisdell, Douglas; Yang, Sen

    2018-01-25

    Lithium ion capacitors possess an ability to bridge the gap between lithium ion battery and supercapacitor. The main concern of fabricating lithium ion capacitors is poor rate capability and cyclic stability of the anode material which uses sluggish faradaic reactions to store an electric charge. Herein, we have fabricated high performance hybrid anode material based on carbon nanofibers (CNFs) and cobalt-nickel sulfide (CoNi 2 S 4 ) nanoparticles via simple electrospinning and electrodeposition methods. Porous and high conducting CNF@CoNi 2 S 4 electrode acts as an expressway network for electronic and ionic diffusion during charging-discharging processes. The effect of anode to cathode mass ratio on the performance has been studied by fabricating lithium ion capacitors with different mass ratios. The surface controlled contribution of CNF@CoNi 2 S 4 electrode was 73% which demonstrates its excellent rate capability. Lithium ion capacitor fabricated with CNF@CoNi 2 S 4 to AC mass ratio of 1:2.6 showed excellent energy density of 85.4 Wh kg -1 with the power density of 150 W kg -1 . Also, even at the high power density of 15 kW kg -1 , the cell provided the energy density of 35 Wh kg -1 . This work offers a new strategy for designing high-performance hybrid anode with the combination of simple and cost effective approaches.

  17. A first-principles investigation of the effect of Pt cluster size on CO and NO oxidation intermediates and energetics

    International Nuclear Information System (INIS)

    Xu, Ye; Getman, Rachel B; Shelton, William Allison Jr.; Schneider, William F

    2008-01-01

    As catalysis research strives toward designing structurally and functionally well-defined catalytic centers containing as few active metal atoms as possible, the importance of understanding the reactivity of small metal clusters, and in particular of systematic comparisons of reaction types and cluster sizes, has grown concomitantly. Here we report density functional theory calculations (GGA-PW91) that probe the relationship between particle size, intermediate structures, and energetics of CO and NO oxidation by molecular and atomic oxygen on Ptx clusters (x = 1-5 and 10). The preferred structures, charge distributions, vibrational spectra, and energetics are systematically examined for oxygen (O2, 2O, and O), CO, CO2, NO, and NO2, for CO/NO co-adsorbed with O2, 2O, and O, and for CO2/NO2 co-adsorbed with O. The binding energies of oxygen, CO, NO, and the oxidation products CO2 and NO2 are all markedly enhanced on Ptx compared to Pt(111), and they trend toward the Pt(111) levels as cluster size increases. Because of the strong interaction of both the reactants and products with the Ptx clusters, deep energy sinks develop on the potential energy surfaces of the respective oxidation processes, indicating worse reaction energetics than on Pt(111). Thus the smallest Pt clusters are less effective for catalyzing CO and NO oxidation in their original state than bulk Pt. Our results further suggests that oxidation by molecular O2 is thermodynamically more facile than oxidation by atomic O on Ptx. Conditions and applications in which the Ptx clusters may be effective catalysts are discussed

  18. High intensive short laser pulse interaction with submicron clusters media

    International Nuclear Information System (INIS)

    Faenov, A. Ya

    2008-01-01

    The interaction of short intense laser pulses with structured targets, such as clusters, exhibits unique features, stemming from the enhanced absorption of the incident laser light compared to solid targets. Due to the increased absorption, these targets are heated significantly, leading to enhanced emission of x rays in the keV range and generation of electrons and multiple charged ions with kinetic energies from tens of keV to tens of MeV. Possible applications of these targets can be an electron/ion source for a table top accelerator, a neutron source for a material damage study, or an x ray source for microscopy or lithography. The overview of recent results, obtained by the high intensive short laser pulse interaction with different submicron clusters media will be presented. High resolution K and L shell spectra of plasma generated by superintense laser irradiation of micron sized Ar, Kr and Xe clusters have been measured with intensity 10"17"-10"19"W/cm"2"and a pulse duration of 30-1000fs. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance toward the higher charge states, which enhances both the X ray line yield and the ion kinetic energy. Irradiation of clusters, produced from such gas mixture, by a fs Ti:Sa laser pulses allows to enhance the soft X ray radiation of Heβ(665.7eV)and Lyα(653.7eV)of Oxygen in 2-8 times compare with the case of using as targets pure CO"2"or N"2"O clusters and reach values 2.8x10"10"(∼3μJ)and 2.7x10"10"(∼2.9μJ)ph/(sr·pulse), respectively. Nanostructure conventional soft X ray images of 100nm thick Mo and Zr foils in a wide field of view (cm"2"scale)with high spatial resolution (700nm)are obtained using the LiF crystals as soft X ray imaging detectors. When the target used for the ion acceleration studies consists of solid density clusters embedded into the background gas, its irradiation by high intensity laser light makes the target

  19. D2O laser pumped by an injection-locked CO2 laser for ion-temperature measurements

    International Nuclear Information System (INIS)

    Okada, Tatsuo; Ohga, Tetsuaki; Yokoo, Masakazu; Muraoka, Katsunori; Akazaki, Masanori.

    1986-01-01

    The cooperative Thomson scattering method is one of the various new techniques proposed for measuring the temperature of ions in nuclear fusion critical plasma, for which a high-performance FIR laser pumped by an injection-locked CO 2 laser is required. This report deals with D 2 O laser with a wavelength of 385 μm which is pumped by injection-locked single-mole TEA CO 2 laser composed of a driver laser and an output-stage laser. A small-sized automatic pre-ionization type laser is employed for the driver. The resonator of the driver laser consists of a plane grating of littrow arrangement and ZnSe plane output mirrors with reflection factor of 50 %. An aperture and ZnSe etalon are inserted in the resonator to produce single transverse- and longitudinal-mode oscillation, respectively. The output-stage laser is also of the automatic pre-ionization type. Theoretically, an injection power of 0.1 pW/mm 3 is required for a CO 2 laser. Single-mode oscillation of several hundred nW/mm 3 can be produced by the CO 2 laser used in this study. Tuning of the output-stage laser is easily controlled by the driver laser. High stability of the injection-locked operation is demonstrated. CO 2 laser beam is introduced into the D 2 O laser through a KCl window to excite D 2 O laser beam in the axial direction. Input and output characteristics of the D 2 O laser are shown. Also presented are typical pulse shapes from the D 2 O laser pumped by a free-running CO 2 laser pulse or by an injection-locked single-mode CO 2 laser pulse. (Nogami, K.)

  20. Pumping characteristics for H2, CO and gas mixture of H2 and CO of distributed ion pump for the SPring-8 storage ring

    International Nuclear Information System (INIS)

    Hirano, Nobuo; Kobari, Toshiaki; Matsumoto, Manabu

    1995-01-01

    Evacuation in the vacuum chamber of the deflection magnet part of the SPring-8 storage ring is planned to be performed with a non evaporable getter pump (NEG) as well as a distributed ion pump (DIP). Pumping characteristics for H 2 , CO and a gas mixture of H 2 and CO of DIP was investigated. The structure of the DIP constructed on a trial basis and an experimental setup to measure the DIP pumping characteristics were described. Pumping speed above 100 L/s per 1 m at the 10 -6 Pa device and pumping speed of about 500 L/s per 1 m at the 10 -7 Pa device were achieved for a gas mixture of H 2 and CO (37% and 55% CO). On the DIP saturated with CO, pumping speed for H 2 is about twice that of pumping speed for CO at the 10 -7 Pa device. Pumping speed for CO is about 1.5 times of the speed for N 2 at the 10 -6 Pa device. Pressure of 1.2 x 10 -8 Pa (9.0 x 10 -11 Torr) is achieved at a room temperature by baking at 150degC for 40 hr. Thus, it was confirmed that the DIP has sufficient pumping characteristics as a pump for the SPring-8 storage ring. (T.H.)

  1. Ligand induced structural isomerism in phosphine coordinated gold clusters revealed by ion mobility mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ligare, Marshall R.; Baker, Erin M.; Laskin, Julia; Johnson, Grant E.

    2017-01-01

    Structural isomerism in ligated gold clusters is revealed using electrospray ionization ion mobility spectrometry mass spectrometry. Phosphine ligated Au8 clusters are shown to adopt more “extended” type structures with increasing exchange of methyldiphenylphosphine (MePPh2) for triphenylphosphine (PPh3). These ligand-dependant structure-property relationships are critical to applications of clusters in catalysis.

  2. Observation of the inhomogeneous spatial distribution of MeV ions accelerated by the hydrodynamic ambipolar expansion of clusters

    International Nuclear Information System (INIS)

    Kanasaki, Masato; Jinno, Satoshi; Sakaki, Hironao; Faenov, Anatoly Ya.; Pikuz, Tatiana A.; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kando, Masaki; Sugiyama, Akira; Kondo, Kiminori; Matsui, Ryutaro; Kishimoto, Yasuaki; Morishima, Kunihiro; Watanabe, Yukinobu; Scullion, Clare; Smyth, Ashley G.; Alejo, Aaron; Doria, Domenico; Kar, Satyabrata; Borghesi, Marco

    2015-01-01

    An inhomogeneous spatial distribution of laser accelerated carbon/oxygen ions produced via the hydrodynamic ambipolar expansion of CO_2 clusters has been measured by using CR-39 detectors. An inhomogeneous etch pits spatial distribution has appeared on the etched CR-39 detector installed on the laser propagation direction, while homogeneous ones are appeared on those installed at 45° and 90° from the laser propagation direction. From the range of ions in CR-39 obtained by using the multi-step etching technique, the averaged energies of carbon/oxygen ions for all directions are determined as 0.78 ± 0.09 MeV/n. The number of ions in the laser propagation direction is about 1.5 times larger than those in other directions. The inhomogeneous etch pits spatial distribution in the laser propagation direction could originate from an ion beam collimation and modulation by the effect of electromagnetic structures created in the laser plasma. - Highlights: • A spatial distribution of ions due to hydrodynamic ambipolar expansion is measured. • The homogeneous ion energy distribution of 0.78 ± 0.09 MeV/n is measured by CR-39. • The number of ions in the laser axis is about 1.5 times larger than other directions.

  3. Decontamination of Metal Ions in Soil by Supercritical CO{sub 2} Extraction with Catecholamine Ligand

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihye; Kim, Hakwon; Park, Kwangheon [Kyunghee University, Yongin (Korea, Republic of)

    2015-10-15

    The role of fuel cladding and reactor vessels is to help prevent the leakage of radioactive materials, including the fission products. However, if these shielding materials are damaged by a severe disaster such as the Fukushima Accident, radioactive materials could leak outside of a power plant site. Indeed, after the Fukushima Accident, radioactive materials have been detected in air and water samples. The air and water pollution lead to soil pollution, which is particularly difficult to decontaminate, as soil pollution has several types that vary according to the characteristics of a pollutant or its area. The existing decontamination methods generate a secondary waste owing to use of chemical toxicity solvents. It is also disadvantageous due to the additional cost of handling them. Therefore, new effective decontamination methods that reduce the use of toxicity solvents are necessary. For example, using supercritical CO{sub 2} has been studied as a new decontamination method. This study examines the method of decontaminating metallic ions inside of the soil using supercritical CO{sub 2} and a catecholamine compound. This study examined the effects of extracting metallic ions inside the soil using supercritical CO{sub 2} and catecholamine as the ligand. Based on these results, it is evident that when only the extraction agent was used, there was no extraction effect and that only when the ligand, co-ligand, and additive were used together was there an extraction effect. Following this, the optimal extraction-agent ratio was confirmed using varying amounts of extraction agents. The most effective extraction ratio of ligand to co-ligand was 1:2 in E-9 when 0.3 ml of H{sub 2}O were added.

  4. One-pot synthesis of nitrogen and sulfur co-doped graphene supported MoS2 as high performance anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Liu, Qiuhong; Wu, Zhenjun; Ma, Zhaoling; Dou, Shuo; Wu, Jianghong; Tao, Li; Wang, Xin; Ouyang, Canbing; Shen, Anli; Wang, Shuangyin

    2015-01-01

    Highlights: • Nitrogen and sulfur co-doped graphene supported MoS 2 nanosheets were successfully prepared and used as anode materials for Li-ion batteries. • The as-prepared anode materials show excellent stability in Li-ion batteries. • The materials show high reversible capacity for lithium ion batteries. - Abstract: Nitrogen and sulfur co-doped graphene supported MoS 2 (MoS 2 /NS-G) nanosheets were prepared through a one-pot thermal annealing method. The as prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectra and electrochemical techniques. The MoS 2 /NS-G shows high reversible capacity about 1200 mAh/g at current density of 150 mA/g and excellent stability in Li-ion batteries. It was demonstrated the co-doping of graphene by N and S could significantly enhance the durability of MoS 2 as anode materials for Li-ion batteries

  5. Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries

    Science.gov (United States)

    Huang, Weifeng; Zhou, Jing; Li, Biao; Ma, Jin; Tao, Shi; Xia, Dingguo; Chu, Wangsheng; Wu, Ziyu

    2014-01-01

    Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V. PMID:24595232

  6. The formation of magnetic silicide Fe3Si clusters during ion implantation

    Science.gov (United States)

    Balakirev, N.; Zhikharev, V.; Gumarov, G.

    2014-05-01

    A simple two-dimensional model of the formation of magnetic silicide Fe3Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

  7. The formation of magnetic silicide Fe3Si clusters during ion implantation

    International Nuclear Information System (INIS)

    Balakirev, N.; Zhikharev, V.; Gumarov, G.

    2014-01-01

    A simple two-dimensional model of the formation of magnetic silicide Fe 3 Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field

  8. Xenon-ion-induced and thermal mixing of Co/Si bilayers and their interplay

    Science.gov (United States)

    Novaković, M.; Zhang, K.; Popović, M.; Bibić, N.; Hofsäss, H.; Lieb, K. P.

    2011-05-01

    Studies on ion-irradiated transition-metal/silicon bilayers demonstrate that interface mixing and silicide phase formation depend sensitively on the ion and film parameters, including the structure of the metal/Si interface. Thin Co layers e-gun evaporated to a thickness of 50 nm on Si(1 0 0) wafers were bombarded at room temperature with 400-keV Xe + ions at fluences of up to 3 × 10 16 cm -2. We used either crystalline or pre-amorphized Si wafers the latter ones prepared by 1.0-keV Ar-ion implantation. The as-deposited or Xe-ion-irradiated samples were then isochronally annealed at temperatures up to 700 °C. Changes of the bilayer structures induced by ion irradiation and/or annealing were investigated with RBS, XRD and HRTEM. The mixing rate for the Co/c-Si couples, Δ σ2/ Φ = 3.0(4) nm 4, is higher than the value expected for ballistic mixing and about half the value typical for spike mixing. Mixing of pre-amorphized Si is much weaker relative to crystalline Si wafers, contrary to previous results obtained for Fe/Si bilayers. Annealing of irradiated samples produces very similar interdiffusion and phase formation patterns above 400 °C as in the non-irradiated Co/Si bilayers: the phase evolution follows the sequence Co 2Si → CoSi → CoSi 2.

  9. Xenon-ion-induced and thermal mixing of Co/Si bilayers and their interplay

    International Nuclear Information System (INIS)

    Novakovic, M.; Zhang, K.; Popovic, M.; Bibic, N.; Hofsaess, H.; Lieb, K.P.

    2011-01-01

    Studies on ion-irradiated transition-metal/silicon bilayers demonstrate that interface mixing and silicide phase formation depend sensitively on the ion and film parameters, including the structure of the metal/Si interface. Thin Co layers e-gun evaporated to a thickness of 50 nm on Si(1 0 0) wafers were bombarded at room temperature with 400-keV Xe + ions at fluences of up to 3 x 10 16 cm -2 . We used either crystalline or pre-amorphized Si wafers the latter ones prepared by 1.0-keV Ar-ion implantation. The as-deposited or Xe-ion-irradiated samples were then isochronally annealed at temperatures up to 700 o C. Changes of the bilayer structures induced by ion irradiation and/or annealing were investigated with RBS, XRD and HRTEM. The mixing rate for the Co/c-Si couples, Δσ 2 /Φ = 3.0(4) nm 4 , is higher than the value expected for ballistic mixing and about half the value typical for spike mixing. Mixing of pre-amorphized Si is much weaker relative to crystalline Si wafers, contrary to previous results obtained for Fe/Si bilayers. Annealing of irradiated samples produces very similar interdiffusion and phase formation patterns above 400 o C as in the non-irradiated Co/Si bilayers: the phase evolution follows the sequence Co 2 Si → CoSi → CoSi 2 .

  10. Properties of ion implanted epitaxial CoSi2/Si(1 0 0) after rapid thermal oxidation

    International Nuclear Information System (INIS)

    Zhao, Q.T.; Kluth, P.; Xu, J.; Kappius, L.; Zastrow, U.; Wang, Z.L.; Mantl, S.

    2000-01-01

    Epitaxial CoSi 2 layers were grown on Si(1 0 0) using molecular beam allotaxy. Boron ion implantations and rapid thermal oxidation (RTO) were performed. During oxidation, SiO 2 formed on the surface of the CoSi 2 layers, and the silicides was pushed into the substrate. The diffusion of boron was slightly retarded during oxidation for the specimen with a 20 nm epitaxial CoSi 2 capping layer as compared to the specimen without CoSi 2 capping layer. The electrical measurements showed that the silicide has good Schottky contacts with the boron doped silicon layer after RTO. A nanometer silicide patterning process, based on local oxidation of silicide (LOCOSI) layer, was also investigated. It shows two back-to-back Schottky diodes between the two separated parts of the silicide

  11. Discussion of CoSA: Clustering of Sparse Approximations

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Derek Elswick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-07

    The purpose of this talk is to discuss the possible applications of CoSA (Clustering of Sparse Approximations) to the exploitation of HSI (HyperSpectral Imagery) data. CoSA is presented by Moody et al. in the Journal of Applied Remote Sensing (“Land cover classification in multispectral imagery using clustering of sparse approximations over learned feature dictionaries”, Vol. 8, 2014) and is based on machine learning techniques.

  12. Silvering substrates after CO2 snow cleaning

    Science.gov (United States)

    Zito, Richard R.

    2005-09-01

    There have been some questions in the astronomical community concerning the quality of silver coatings deposited on substrates that have been cleaned with carbon dioxide snow. These questions center around the possible existence of carbonate ions left behind on the substrate by CO2. Such carbonate ions could react with deposited silver to produce insoluble silver carbonate, thereby reducing film adhesion and reflectivity. Carbonate ions could be produced from CO2 via the following mechanism. First, during CO2 snow cleaning, a small amount of moisture can condense on a surface. This is especially true if the jet of CO2 is allowed to dwell on one spot. CO2 gas can dissolve in this moisture, producing carbonic acid, which can undergo two acid dissociations to form carbonate ions. In reality, it is highly unlikely that charged carbonate ions will remain stable on a substrate for very long. As condensed water evaporates, Le Chatelier's principle will shift the equilibrium of the chain of reactions that produced carbonate back to CO2 gas. Furthermore, the hydration of CO2 reaction of CO2 with H20) is an extremely slow process, and the total dehydrogenation of carbonic acid is not favored. Living tissues that must carry out the equilibration of carbonic acid and CO2 use the enzyme carbonic anhydrase to speed up the reaction by a factor of one million. But no such enzymatic action is present on a clean mirror substrate. In short, the worst case analysis presented below shows that the ratio of silver atoms to carbonate radicals must be at least 500 million to one. The results of chemical tests presented here support this view. Furthermore, film lift-off tests, also presented in this report, show that silver film adhesion to fused silica substrates is actually enhanced by CO2 snow cleaning.

  13. First multispacecraft ion measurements in and near the Earth’s magnetosphere with the identical Cluster ion spectrometry (CIS experiment

    Directory of Open Access Journals (Sweden)

    H. Rème

    2001-09-01

    Full Text Available On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS experiment measures the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+ from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmposition and DIstribution Function analyser (CIS1/CODIF, giving the mass per charge composition with medium (22.5° angular resolution, and a Hot Ion Analyser (CIS2/HIA, which does not offer mass resolution but has a better angular resolution (5.6° that is adequate for ion beam and solar wind measurements. Each analyser has two different sensitivities in order to increase the dynamic range. First tests of the instruments (commissioning activities were achieved from early September 2000 to mid January 2001, and the operation phase began on 1 February 2001. In this paper, first results of the CIS instruments are presented showing the high level performances and capabilities of the instruments. Good examples of data were obtained in the central plasma sheet, magnetopause crossings, magnetosheath, solar wind and cusp measurements. Observations in the auroral regions could also be obtained with the Cluster spacecraft at radial distances of 4–6 Earth radii. These results show the tremendous interest of multispacecraft measurements with identical instruments and open a new area in magnetospheric and solar wind-magnetosphere interaction physics.Key words. Magnetospheric physics (magnetopause, cusp and boundary layers; magnetopheric configuration and dynamics; solar wind - magnetosphere interactions

  14. Joint local and global consistency on interdocument and interword relationships for co-clustering.

    Science.gov (United States)

    Bao, Bing-Kun; Min, Weiqing; Li, Teng; Xu, Changsheng

    2015-01-01

    Co-clustering has recently received a lot of attention due to its effectiveness in simultaneously partitioning words and documents by exploiting the relationships between them. However, most of the existing co-clustering methods neglect or only partially reveal the interword and interdocument relationships. To fully utilize those relationships, the local and global consistencies on both word and document spaces need to be considered, respectively. Local consistency indicates that the label of a word/document can be predicted from its neighbors, while global consistency enforces a smoothness constraint on words/documents labels over the whole data manifold. In this paper, we propose a novel co-clustering method, called co-clustering via local and global consistency, to not only make use of the relationship between word and document, but also jointly explore the local and global consistency on both word and document spaces, respectively. The proposed method has the following characteristics: 1) the word-document relationships is modeled by following information-theoretic co-clustering (ITCC); 2) the local consistency on both interword and interdocument relationships is revealed by a local predictor; and 3) the global consistency on both interword and interdocument relationships is explored by a global smoothness regularization. All the fitting errors from these three-folds are finally integrated together to formulate an objective function, which is iteratively optimized by a convergence provable updating procedure. The extensive experiments on two benchmark document datasets validate the effectiveness of the proposed co-clustering method.

  15. Electrodeposited binder-free NiCo2O4@carbon nanofiber as a high performance anode for lithium ion batteries

    Science.gov (United States)

    Zhang, Jie; Chu, Ruixia; Chen, Yanli; Jiang, Heng; Zhang, Ying; Huang, Nay Ming; Guo, Hang

    2018-03-01

    Binder-free nickel cobaltite on a carbon nanofiber (NiCo2O4@CNF) anode for lithium ion batteries was prepared via a two-step procedure of electrospinning and electrodeposition. The CNF was obtained by annealing electrospun poly-acrylonitrile (PAN) in nitrogen (N2). The NiCo2O4 nanostructures were then grown on the CNF by electrodeposition, followed by annealing in air. Experimental results showed that vertically aligned NiCo2O4 nanosheets had uniformly grown on the surface of the CNF, forming an interconnected network. The NiCo2O4@CNF possessed considerable lithium storage capacity and cycling stability. It exhibited a high reversible capacity of 778 mAhg-1 after 300 cycles at a current density of 0.25 C (1 C = 890 mAg-1) with an average capacity loss rate of 0.05% per cycle. The NiCo2O4@CNF had considerable rate capacities, delivering a capacity of 350 mAhg-1 at a current density of 2.0 C. The outstanding electrochemical performance can be mainly attributed to the following: (1) The nanoscale structure of NiCo2O4 could not only shorten the diffusion path of lithium ions and electrons but also increase the specific surface area, providing more active sites for electrochemical reactions. (2) The CNF with considerable mechanical strength and electrical conductivity could function as an anchor for the NiCo2O4 nanostructure and ensure an efficient electron transfer. (3) The porous structure resulted in a high specific surface area and an effective buffer for the volume changes during the repeated charge-discharge processes. Compared with a conventional hydrothermal method, electrodeposition could significantly simplify the preparation of NiCo2O4, with a shorter preparation period and lower energy consumption. This work provides an alternative strategy to obtain a high performance anode for lithium ion batteries.

  16. Time-of-flight secondary ion mass spectrometry with energetic cluster ion impact ionization for highly sensitive chemical structure characterization

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, K., E-mail: k.hirata@aist.go.jp [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Saitoh, Y.; Chiba, A.; Yamada, K.; Narumi, K. [Takasaki Advanced Radiation Research Institute (TARRI), Japan Atomic Energy Agency (JAEA), Takasaki, Gumma 370-1292 (Japan)

    2013-11-01

    Energetic cluster ions with energies of the order of sub MeV or greater were applied to time-of-flight (TOF) secondary ion (SI) mass spectrometry. This gave various advantages including enhancement of SIs required for chemical structure characterization and prevention of charging effects in SI mass spectra for organic targets. We report some characteristic features of TOF SI mass spectrometry using energetic cluster ion impact ionization and discuss two future applications of it.

  17. Cluster ions and van der Waals molecules

    CERN Document Server

    Smirnov, Boris M

    1992-01-01

    This review discusses current ideas in the physics and chemistry of cluster ions and Van der Waals molecules as well as presenting numerical data on their parameters and the processes involving them. It is also a detailed reference on basic data relating to many species.

  18. Pleiades cluster. IV. The visit of a molecular CO cloud

    International Nuclear Information System (INIS)

    Breger, M.

    1987-01-01

    The location, size, and mass of the CO molecular cloud seen in the direction of the Pleiades cluster is determined from a study of the polarization and reddening of cluster members and nonmembers. Arguments are presented against both a foreground and background location of the molecular cloud, so that the cloud should be presently situated inside the cluster. Stellar reddening determinations with the appropriate value of R = 3.3 for the region, as well as star counts, lead to a determination of a total extinction of A(V) in the range of 1.0-1.6 mag for the central region of the CO cloud. The extinction determinations for cluster members and background stars indicate a mass of 20 solar masses for the CO cloud visiting the Pleiades cluster. 20 references

  19. Large clusters of co-expressed genes in the Drosophila genome.

    Science.gov (United States)

    Boutanaev, Alexander M; Kalmykova, Alla I; Shevelyov, Yuri Y; Nurminsky, Dmitry I

    2002-12-12

    Clustering of co-expressed, non-homologous genes on chromosomes implies their co-regulation. In lower eukaryotes, co-expressed genes are often found in pairs. Clustering of genes that share aspects of transcriptional regulation has also been reported in higher eukaryotes. To advance our understanding of the mode of coordinated gene regulation in multicellular organisms, we performed a genome-wide analysis of the chromosomal distribution of co-expressed genes in Drosophila. We identified a total of 1,661 testes-specific genes, one-third of which are clustered on chromosomes. The number of clusters of three or more genes is much higher than expected by chance. We observed a similar trend for genes upregulated in the embryo and in the adult head, although the expression pattern of individual genes cannot be predicted on the basis of chromosomal position alone. Our data suggest that the prevalent mechanism of transcriptional co-regulation in higher eukaryotes operates with extensive chromatin domains that comprise multiple genes.

  20. Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Okunev, V.D., E-mail: okunev@mail.fti.ac.donetsk.ua [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Samoilenko, Z.A. [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S.J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Wolny-Marszałek, M.; Jeżabek, M. [Institute of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Varyukhin, V.N. [Donetsk Physiko-Technical Institute, Ukrainian Academy of Sciences, av. Nauki 46, 03028 Kiev (Ukraine); Antoshina, I.A. [Obninsk State Technical University of Atomic Energy, 249020 Obninsk (Russian Federation)

    2016-02-01

    We show that cluster magnetism in ferromagnetic amorphous Fe{sub 67}Cr{sub 18}B{sub 15} alloy is related to the presence of large, D=150–250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30–100 Å, α-(Fe, Cr) and Fe{sub 3}B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10–20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×10{sup 18} ions/cm{sup 2}) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×10{sup 18} ions/cm{sup 2}, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T)~T{sup 2} is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×10{sup 18} ions/cm{sup 2}, the transition to a dependence ρ(T)~T{sup 1/2} is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×10{sup 18} ions/cm{sup 2}, a return to the dependence ρ(T)~T{sup 2} is observed. - Highlights: • The samples at high dose of ion irradiation become more homogeneous. • Gigantic increase in density of the samples (twice as much) is observed. • Ferromagnetism in large Fe–Cr clusters is restored. • Ferromagnetism of Fe–Cr clusters suppresses local superconductivity in them. • The participation of quantum defects in scattering of electrons is returned.

  1. Reaction of O+, CO+, and CH+ ions with atomic hydrogen

    International Nuclear Information System (INIS)

    Federer, W.; Villinger, H.; Howorka, F.; Lindinger, W.; Tosis, P.; Bassi, D.; Ferguson, E.

    1984-01-01

    Rate coefficients for reactions of the ions O + , CO + , and CH + with atomic hydrogen have been measured for the first time at 300 K. This provides basic data for the ion chemistry of planetary atmospheres, cometary atmospheres, and interstellar molecular clouds. The O + +H measurement supports quantal calculations of this reaction. The CO + +H reaction provides an example of partial spin nonconservation in a charge-transfer reaction occurring in a deep potential well. Reactions of the same ions with H 2 that have been measured elsewhere are also reported

  2. Experimental studies of the formation of cluster ions formed by corona discharge in an atmosphere containing SO2, NH3, and H2O

    DEFF Research Database (Denmark)

    Hvelplund, Preben; Pedersen, Jens Olaf Pepke; Støchkel, Kristian

    2013-01-01

    Abstract We report on studies of ion-induced nucleation in a corona discharge taking place in an atmosphere containing SO2, NH3, and H2O at standard temperature and pressure. Positive ions such as H3O+(H2O)n, NH4+(H2O)n, and H+(H2SO4)(H2O)n and negative ions such as HSO5-(H2O)n, SO4-(H2O)n, HSO4-(H......5-, which has been observed in many studies, in our experiments is contaminated by O2-(HNO3)(H2O) ions, and this may also have been the case in other experiments. Finally an ion with m/z = 232 (where m is the cluster mass in amu and z is the charge state), capable of attaching H2O...

  3. Wear Performance of Sequentially Cross-Linked Polyethylene Inserts against Ion-Treated CoCr, TiNbN-Coated CoCr and Al2O3 Ceramic Femoral Heads for Total Hip Replacement

    Directory of Open Access Journals (Sweden)

    Christian Fabry

    2015-02-01

    Full Text Available The aim of the present study was to evaluate the biotribology of current surface modifications on femoral heads in terms of wettability, polyethylene wear and ion-release behavior. Three 36 mm diameter ion-treated CoCr heads and three 36 mm diameter TiNbN-coated CoCr heads were articulated against sequentially cross-linked polyethylene inserts (X3 in a hip joint simulator, according to ISO 14242. Within the scope of the study, the cobalt ion release in the lubricant, as well as contact angles at the bearing surfaces, were investigated and compared to 36 mm alumina ceramic femoral heads over a period of 5 million cycles. The mean volumetric wear rates were 2.15 ± 0.18 mm3·million cycles−1 in articulation against the ion-treated CoCr head, 2.66 ± 0.40 mm3·million cycles−1 for the coupling with the TiNbN-coated heads and 2.17 ± 0.40 mm3·million cycles−1 for the ceramic heads. The TiNbN-coated femoral heads showed a better wettability and a lower ion level in comparison to the ion-treated CoCr heads. Consequently, the low volumes of wear debris, which is comparable to ceramics, and the low concentration of metal ions in the lubrication justifies the use of coated femoral heads.

  4. Electron induced formation and stability of molecular and cluster ions in gas phase and superfluid helium nanodroplets

    International Nuclear Information System (INIS)

    Aleem, M. A.

    2010-01-01

    -induced reactions of the molecules doped into superfluid helium nanodroplets. Pick up of more than one molecule has lead to the formation of ultracold neutral clusters inside the helium droplets. Electron attachment to He nanodroplets doped with ammonia has embarked a synthetic chemistry, forming hydrazine anions, followed by intermediate ion complexes at freezing temperature of 0.37 K of the helium environment. Also a concomitant solvation effect for hydrazine anions has been observed. Electron ionization of He droplets containing ammonia and water co-doped with fullerenes has shown unique sequence of the formation and fragmentation of cluster ions following electron-induced ionization processes. A novel ion-molecule reaction has been observed and established following electron ionization of water and fullerene co-doped into helium nanodroplets. (author)

  5. Physicochemical properties of synthetic nano-birnessite and its enhanced scavenging of Co{sup 2+} and Sr{sup 2+} ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Metwally, S.S., E-mail: sicosad@hotmail.com; Ghaly, M.; El-Sherief, E.A.

    2017-06-01

    Nano-birnessite was prepared, characterized and used for removal of cobalt and strontium ions from aqueous solutions. Scanning electron microscope and atomic force microscope images indicated that the particles of the prepared material are presented in the nano-scale form, the grain size was found in a range of 58–95 nm. Specific surface area of the prepared nano-birnessite was determined and found to be 200.54 m{sup 2}/g. The Capacities of nano-birnessite for cobalt and strontium are 2.97 and 3.04 meq/g, respectively. The kinetic studies indicated that the sorption of the two ions obeys pseudo-second-order model and controlled by an intra-particle diffusion mechanism. The diffusivity of Co{sup 2+} and Sr{sup 2+} ions onto nano-birnessite was determined and indicated that the sorption is chemisorption process. Hence, nano-birnessite material is an efficient sorbent and can be used to decrease the influx of pollutants, such as; Co{sup 2+} and Sr{sup 2+} ions to the environment or their removal from contaminated media. - Graphical abstract: 3D AFM images for nano-birnessite. - Highlights: • Nano-birnessite was prepared using sol-gel method. • It was characterized using different analytical techniques. • Sorption of cobalt and strontium ions onto nano-birnessite was investigated. • Kinetic studies and some kinetic models were tested for the sorption process. • Nano-birnessite exhibited high sorption capacity compared to other sorbents obtained in the literature.

  6. Pb3O4 type antimony oxides MSb2O4 (M = Co, Ni) as anode for Li-ion batteries

    International Nuclear Information System (INIS)

    Jibin, A.K.; Reddy, M.V.; Subba Rao, G.V.; Varadaraju, U.V.; Chowdari, B.V.R.

    2012-01-01

    Graphical abstract: Isostructural Pb 3 O 4 type MSb 2 O 4 (M = Co, Ni) compounds were investigated as possible anodes for lithium ion batteries. The reversible capacity is due to electrochemically active Sb and the transition metal and Li 2 O form an inactive matrix which buffers volume variations associated with alloying-de-alloying of antimony. Highlights: ► Isostructural MSb 2 O 4 (M = Co, Ni) were studied as anode for LIBs for first time. ► Li/MSb 2 O 4 (M = Co, Ni) cells displayed reversibility due to electrochemically active Sb. ► CoSb 2 O 4 showed good reversibility compared to NiSb 2 O 4 . - Abstract: Polycrystalline samples of isostructural MSb 2 O 4 (M = Co, Ni) have been prepared by solid state synthesis and lithium-storage is investigated as possible anode materials for lithium-ion batteries. The reaction mechanism of lithium with MSb 2 O 4 (M = Co, Ni) is explored by galvanostatic cycling, cyclic voltammogram and ex situ studies. Both CoSb 2 O 4 and NiSb 2 O 4 exhibit similar electrochemical behavior and show reversible capacity of 490 and 412 mAh g −1 respectively in the first cycle. Reversible alloying de-alloying of Li x Sb takes place in an amorphous matrix of M (Co, Ni) and Li 2 O during electrochemical cycling.

  7. Xenon-ion-induced and thermal mixing of Co/Si bilayers and their interplay

    Energy Technology Data Exchange (ETDEWEB)

    Novakovic, M. [VINCA Institute of Nuclear Sciences, 11001 Belgrade (Serbia); II. Physikalisches Institut, Georg-August-Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Zhang, K. [II. Physikalisches Institut, Georg-August-Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Popovic, M.; Bibic, N. [VINCA Institute of Nuclear Sciences, 11001 Belgrade (Serbia); II. Physikalisches Institut, Georg-August-Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Hofsaess, H. [II. Physikalisches Institut, Georg-August-Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Lieb, K.P., E-mail: plieb@gwdg.d [II. Physikalisches Institut, Georg-August-Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

    2011-05-01

    Studies on ion-irradiated transition-metal/silicon bilayers demonstrate that interface mixing and silicide phase formation depend sensitively on the ion and film parameters, including the structure of the metal/Si interface. Thin Co layers e-gun evaporated to a thickness of 50 nm on Si(1 0 0) wafers were bombarded at room temperature with 400-keV Xe{sup +} ions at fluences of up to 3 x 10{sup 16} cm{sup -2}. We used either crystalline or pre-amorphized Si wafers the latter ones prepared by 1.0-keV Ar-ion implantation. The as-deposited or Xe-ion-irradiated samples were then isochronally annealed at temperatures up to 700 {sup o}C. Changes of the bilayer structures induced by ion irradiation and/or annealing were investigated with RBS, XRD and HRTEM. The mixing rate for the Co/c-Si couples, {Delta}{sigma}{sup 2}/{Phi} = 3.0(4) nm{sup 4}, is higher than the value expected for ballistic mixing and about half the value typical for spike mixing. Mixing of pre-amorphized Si is much weaker relative to crystalline Si wafers, contrary to previous results obtained for Fe/Si bilayers. Annealing of irradiated samples produces very similar interdiffusion and phase formation patterns above 400 {sup o}C as in the non-irradiated Co/Si bilayers: the phase evolution follows the sequence Co{sub 2}Si {yields} CoSi {yields} CoSi{sub 2}.

  8. Self-Assembled Gold Nano-Ripple Formation by Gas Cluster Ion Beam Bombardment.

    Science.gov (United States)

    Tilakaratne, Buddhi P; Chen, Quark Y; Chu, Wei-Kan

    2017-09-08

    In this study, we used a 30 keV argon cluster ion beam bombardment to investigate the dynamic processes during nano-ripple formation on gold surfaces. Atomic force microscope analysis shows that the gold surface has maximum roughness at an incident angle of 60° from the surface normal; moreover, at this angle, and for an applied fluence of 3 × 10 16 clusters/cm², the aspect ratio of the nano-ripple pattern is in the range of ~50%. Rutherford backscattering spectrometry analysis reveals a formation of a surface gradient due to prolonged gas cluster ion bombardment, although the surface roughness remains consistent throughout the bombarded surface area. As a result, significant mass redistribution is triggered by gas cluster ion beam bombardment at room temperature. Where mass redistribution is responsible for nano-ripple formation, the surface erosion process refines the formed nano-ripple structures.

  9. CoFe2O4/carbon nanotube aerogels as high performance anodes for lithium ion batteries

    Directory of Open Access Journals (Sweden)

    Xin Sun

    2017-04-01

    Full Text Available High-performance lithium ion batteries (LIBs require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional (3D aerogels composed of cobalt ferrite (CoFe2O4, CFO nanoparticles (NPs and carbon nanotubes (CNTs are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co2+ and Fe3+ can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content (20 wt% delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g−1 at 0.1 A g−1 and a high specific capacity of 874 mAh g−1 after 160 cycles at 1 A g−1. This work provides a facile and low cost route to fabricate high performance anodes for LIBs. Keywords: Alginate, Aerogels, Cobalt ferrite, Anode, Lithium-ion battery

  10. Formation of ternary CaUO2(CO3)3(2-) and Ca2UO2(CO3)3(aq) complexes under neutral to weakly alkaline conditions.

    Science.gov (United States)

    Lee, Jun-Yeop; Yun, Jong-Il

    2013-07-21

    The chemical behavior of ternary Ca-UO2-CO3 complexes was investigated by using time-resolved laser fluorescence spectroscopy (TRLFS) in combination with EDTA complexation at pH 7-9. A novel TRLFS revealed two distinct fluorescence lifetimes of 12.7 ± 0.2 ns and 29.2 ± 0.4 ns for uranyl complexes which were formed increasingly dependent upon the calcium ion concentration, even though nearly indistinguishable fluorescence peak shapes and positions were measured for both Ca-UO2-CO3 complexes. For identifying the stoichiometric number of complexed calcium ions, slope analysis in terms of relative fluorescence intensity versus calcium concentration was employed in a combination with the complexation reaction of CaEDTA(2-) by adding EDTA. The formation of CaUO2(CO3)3(2-) and Ca2UO2(CO3)3(aq) was identified under given conditions and their formation constants were determined at I = 0.1 M Na/HClO4 medium, and extrapolated to infinitely dilute solution using specific ion interaction theory (SIT). As a result, the formation constants for CaUO2(CO3)3(2-) and Ca2UO2(CO3)3(aq) were found to be log β113(0) = 27.27 ± 0.14 and log β213(0) = 29.81 ± 0.19, respectively, providing that the ternary Ca-UO2-CO3 complexes were predominant uranium(vi) species at neutral to weakly alkaline pH in the presence of Ca(2+) and CO3(2-) ions.

  11. CO dissociation on magnetic Fen clusters

    KAUST Repository

    Jedidi, Abdesslem

    2014-01-01

    This work theoretically investigates the CO dissociation on Fen nanoparticles, for n in the range of 1-65, focusing on size dependence in the context of the initial step of the Fischer-Tropsch reaction. CO adsorbs molecularly through its C-end on a triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom is adsorbed on a triangular facet. In the most stable situation, the two adsorbed atoms remain close together, both having in common one shared first-neighbor iron atom. There is a partial spin quenching of the neighboring Fe atoms, which become more positively charged than the other Fe atoms. The shared surface iron atom resembles a metal-cation from a complex. Despite the small size of the iron cluster considered, fluctuations due to specific configurations do not influence properties for n > 25 and global trends seem significant.

  12. Structure investigation of metal ions clustering in dehydrated gel using x-ray anomalous dispersion effect

    CERN Document Server

    Soejima, Y; Sugiyama, M; Annaka, M; Nakamura, A; Hiramatsu, N; Hara, K

    2003-01-01

    The structure of copper ion clusters in dehydrated N-isopropylacrylamide/sodium acrylate (NIPA/SA) gel has been studied by means of small angle X-ray scattering (SAXS) method. In order to distinguish the intensity scattered by Cu ions, the X-ray anomalous dispersion effect around the Cu K absorption edge has been coupled with SAXS. It is found that the dispersion effect dependent on the incident X-ray energy is remarkable only at the momentum transfer q = 0.031 A sup - sup 1 , where a SAXS peak is observed. The results indicate that copper ions form clusters in the dehydrated gel, and that the mean size of clusters is the same as that of SA clusters produced by microphase separation. It is therefore naturally presumed that copper ions are adsorbed into the SA molecules. On the basis of the presumption, a mechanism is proposed for microphase-separation and clustering of Cu ions.

  13. Co2 and Co3 Mixed Cluster Secondary Building Unit Approach toward a Three-Dimensional Metal-Organic Framework with Permanent Porosity

    Directory of Open Access Journals (Sweden)

    Meng-Yao Chao

    2018-03-01

    Full Text Available Large and permanent porosity is the primary concern when designing metal-organic frameworks (MOFs for specific applications, such as catalysis and drug delivery. In this article, we report a MOF Co11(BTB6(NO34(DEF2(H2O14 (1, H3BTB = 1,3,5-tris(4-carboxyphenylbenzene; DEF = N,N-diethylformamide via a mixed cluster secondary building unit (SBU approach. MOF 1 is sustained by a rare combination of a linear trinuclear Co3 and two types of dinuclear Co2 SBUs in a 1:2:2 ratio. These SBUs are bridged by BTB ligands to yield a three-dimensional (3D non-interpenetrated MOF as a result of the less effective packing due to the geometrically contrasting SBUs. The guest-free framework of 1 has an estimated density of 0.469 g cm−3 and exhibits a potential solvent accessible void of 69.6% of the total cell volume. The activated sample of 1 exhibits an estimated Brunauer-Emmett-Teller (BET surface area of 155 m2 g−1 and is capable of CO2 uptake of 58.61 cm3 g−1 (2.63 mmol g−1, 11.6 wt % at standard temperature and pressure in a reversible manner at 195 K, showcasing its permanent porosity.

  14. Glassy behavior in the layered perovskites La{sub 2-x}Sr{sub x}CoO{sub 4}(1.1{<=}x{<=}1.3)

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S., E-mail: sanseb68@yahoo.co.in [Department of Physics, University of Burdwan, Burdwan 713104 (India); Mukherjee, Rajarshi [Department .of Physics, University of Burdwan, Burdwan 713104 (India); Banerjee, S.; Ranganathan, R. [Saha Institute of Nuclear Physics, Kolkata 700 064 (India); Kumar, Uday [Department of Physical Sciences, Indian Institute of Science Education and Research - Kolkata, Mohonpur 741252 (India)

    2012-03-15

    The glassy behavior of the phase segregated state in the layered cobaltite La{sub 2-x}Sr{sub x}CoO{sub 4} has been studied. The role of the inter-cluster interactions as well as the disordered spins at the paramagnetic-ferromagnetic interface, behind the observed glassy behavior have been investigated. The disordered spins at the interface appear to be strongly pinned, and they contribute little to the observed glassy behavior. On the other hand, the inter-cluster interactions play the key role. Both the Co{sup 4+} and Co{sup 3+} ions are in the intermediate spin state. - Highlights: Black-Right-Pointing-Pointer Phase segregated state of cobaltite La{sub 2-x}Sr{sub x}CoO{sub 4} for (1.1{<=}x{<=}1.3) to find the origin of the observed glassy behavior. Black-Right-Pointing-Pointer Result of the frequency dependent ac susceptibility measurement excludes the possibility of any spin glass phase, hints strong inter-cluster interactions. Black-Right-Pointing-Pointer Relaxation experiments confirm the system to be a collection of clusters with two preferred sizes. Black-Right-Pointing-Pointer The glassy behavior originates from strong inter-cluster interactions.

  15. Molecular dynamics simulations to examine structure, energetics, and evaporation/condensation dynamics in small charged clusters of water or methanol containing a single monatomic ion.

    Science.gov (United States)

    Daub, Christopher D; Cann, Natalie M

    2012-11-01

    We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at different temperatures and (2) those with a surrounding inert (Ar) gas of varying temperature. We examine these clusters over a range of sizes, from almost bare ions up to 40 solvent molecules. We report data on the evaporation and condensation of solvent from the clusters and argue that the observed temperature dependence of evaporation in the smallest clusters demonstrates that the presence of heated gas alone cannot, in most cases, solely account for bare ion production in electrospray ionization (ESI), neglecting the key contribution of the electric field. We also present our findings on the structure and energetics of the clusters as a function of size. Our data agree well with the abundant literature on hydrated ion clusters and offer some novel insight into the structure of methanol and ion clusters, especially those with a Cl(-) anion, where we observe the presence of chain-like structures of methanol molecules. Finally, we provide some data on the reparameterizations necessary to simulate ions in methanol using the separately developed Drude oscillator models for methanol and for ions in water.

  16. A theoretical investigation of the collective acceleration of cluster ions with accelerated potential waves

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Enjoji, Hiroshi; Kawaguchi, Motoichi; Noritake, Toshiya

    1984-01-01

    A theoretical treatment of the acceleration of cluster ions for additional heating of fusion plasma using the trapping effect in an accelerated potential wave is described. The conceptual design of the accelerator is the same as that by Enjoji, and the potential wave used is sinusoidal. For simplicity, collisions among cluster ions and the resulting breakups are neglected. The masses of the cluster ions are specified to range from 100 m sub(D) to 1000 m sub(D) (m sub(D): mass of a deuterium atom). Theoretical treatment is carried out only for the injection velocity which coincides with the phase velocity of the applied wave at the entrance of the accelerator. An equation describing the rate for successful acceleration of ions with a certain mass is deduced for the continuous injection of cluster ions. Computation for a typical mass distribution shows that more than 70% of the injected particles are effectively accelerated. (author)

  17. Binding energy and preferred adsorption sites of CO on gold and silver-gold cluster cations: adsorption kinetics and quantum chemical calculations.

    Science.gov (United States)

    Neumaier, Marco; Weigend, Florian; Hampe, Oliver; Kappes, Manfred M

    2008-01-01

    We revisit the reactivity of trapped pure gold (Au(n)+, n cations (Ag(m)Au(n)+, m + n carbon monoxide as studied in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The experimental results are discussed in terms of ab initio computations which provide a comprehensive picture of the chemical binding behaviour (like binding energy, adsorption sites, associated vibrational frequencies) of CO to the noble metal as a function of cluster size and composition. Starting from results for pure gold cluster cations for which an overall decrease of CO binding energy with increasing cluster size was experimentally observed--from about 1.09 +/- 0.1 eV (for n = 6) to below 0.65 +/- 0.1 eV (for n > 26) we demonstrate that metal--CO bond energies correlate with the total electron density and with the energy of the lowest unoccupied molecular orbital (LUMO) on the bare metal cluster cation as obtained by density functional theory (DFT) computations. This is a consequence of the predominantly sigma-donating character of the CO-M bond. Further support for this concept is found by contrasting the predictions of binding energies to the experimental results for small alloy cluster cations (Ag(m)Au(n)+, 4 < m + n < 7) as a function of composition. Here, binding energy drops with increasing silver content, while CO still binds always in a head-on fashion to a gold atom. Finally we show how the CO stretch frequency of Ag(m)Au(n)CO+ may be used to identify possible adsorption sites and pre-screen favorable isomers.

  18. Facile synthesis of single-crystal mesoporous CoNiO2 nanosheets assembled flowers as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Liu, Yanguo; Zhao, Yanyan; Yu, Yanlong; Ahmad, Mashkoor; Sun, Hongyu

    2014-01-01

    Highlights: • Mesoporous CoNiO 2 microflowers have been synthesized. • Li-ion batteries performance of CoNiO 2 has been investigated. • CoNiO 2 structure delivers high capacity, good cycling stability and high rate capability. • The electrochemical performance is attributed to the mesoporous nature and the 3D structure. • CoNiO 2 can be considered to be an attractive candidate as an electrode material for LIBs. - Abstract: Mesoporous CoNiO 2 microflowers assembled with single-crystal nanosheets were successfully synthesized by a hydrothermal method and subsequent annealing process and their lithium storage capacity were investigated. The structural and compositional analysis of the mesoporous CoNiO 2 microflowers has been studied by X-ray diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The Bruauer–Emmett–Teller specific surface area of CoNiO 2 microflowers has been calculated by the nitrogen isotherm curve and pore size distribution has been determined by the Barret–Joyner–Halenda method. It has been found that the as-prepared CoNiO 2 electrodes delivered satisfied capacity, good cycling stability and rate capability. The improved electrochemical performance is attributed to the mesoporous nature and the 3D assembled structure. Therefore, such a structure can be considered to be an attractive candidate as an electrode material for lithium-ion batteries

  19. Titanium Insertion into CO Bonds in Anionic Ti-CO2 Complexes.

    Science.gov (United States)

    Dodson, Leah G; Thompson, Michael C; Weber, J Mathias

    2018-03-22

    We explore the structures of [Ti(CO 2 ) y ] - cluster anions using infrared photodissociation spectroscopy and quantum chemistry calculations. The existence of spectral signatures of metal carbonyl CO stretching modes shows that insertion of titanium atoms into C-O bonds represents an important reaction during the formation of these clusters. In addition to carbonyl groups, the infrared spectra show that the titanium center is coordinated to oxalato, carbonato, and oxo ligands, which form along with the metal carbonyls. The presence of a metal oxalato ligand promotes C-O bond insertion in these systems. These results highlight the affinity of titanium for C-O bond insertion processes.

  20. Antiferromagnetic exchange coupling measurements on single Co clusters

    Science.gov (United States)

    Wernsdorfer, W.; Leroy, D.; Portemont, C.; Brenac, A.; Morel, R.; Notin, L.; Mailly, D.

    2009-03-01

    We report on single-cluster measurements of the angular dependence of the low-temperature ferromagnetic core magnetization switching field in exchange-coupled Co/CoO core-shell clusters (4 nm) using a micro-bridge DC superconducting quantum interference device (μ-SQUID). It is observed that the coupling with the antiferromagnetic shell induces modification in the switching field for clusters with intrinsic uniaxial anisotropy depending on the direction of the magnetic field applied during the cooling. Using a modified Stoner-Wohlfarth model, it is shown that the core interacts with two weakly coupled and asymmetrical antiferromagnetic sublattices. Ref.: C. Portemont, R. Morel, W. Wernsdorfer, D. Mailly, A. Brenac, and L. Notin, Phys. Rev. B 78, 144415 (2008)

  1. Are clusters important in understanding the mechanisms in atmospheric pressure ionization? Part 1: Reagent ion generation and chemical control of ion populations.

    Science.gov (United States)

    Klee, Sonja; Derpmann, Valerie; Wißdorf, Walter; Klopotowski, Sebastian; Kersten, Hendrik; Brockmann, Klaus J; Benter, Thorsten; Albrecht, Sascha; Bruins, Andries P; Dousty, Faezeh; Kauppila, Tiina J; Kostiainen, Risto; O'Brien, Rob; Robb, Damon B; Syage, Jack A

    2014-08-01

    It is well documented since the early days of the development of atmospheric pressure ionization methods, which operate in the gas phase, that cluster ions are ubiquitous. This holds true for atmospheric pressure chemical ionization, as well as for more recent techniques, such as atmospheric pressure photoionization, direct analysis in real time, and many more. In fact, it is well established that cluster ions are the primary carriers of the net charge generated. Nevertheless, cluster ion chemistry has only been sporadically included in the numerous proposed ionization mechanisms leading to charged target analytes, which are often protonated molecules. This paper series, consisting of two parts, attempts to highlight the role of cluster ion chemistry with regard to the generation of analyte ions. In addition, the impact of the changing reaction matrix and the non-thermal collisions of ions en route from the atmospheric pressure ion source to the high vacuum analyzer region are discussed. This work addresses such issues as extent of protonation versus deuteration, the extent of analyte fragmentation, as well as highly variable ionization efficiencies, among others. In Part 1, the nature of the reagent ion generation is examined, as well as the extent of thermodynamic versus kinetic control of the resulting ion population entering the analyzer region.

  2. Evaluation of secondary ion yield enhancement from polymer material by using TOF-SIMS equipped with a gold cluster ion source

    Energy Technology Data Exchange (ETDEWEB)

    Aimoto, K. [Department of Applied Physics, Faculty of Engineering, Seikei University, 3-3-1 Kichijioji-Kitamachi, Musashino-shi, Tokyo 180-8633 (Japan)]. E-mail: dm053502@cc.seikei.ac.jp; Aoyagi, S. [Department of Regional Development, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu-cho, Matsue-shi, Shimane 690-8504 (Japan); Kato, N. [Department of Applied Physics, Faculty of Engineering, Seikei University, 3-3-1 Kichijioji-Kitamachi, Musashino-shi, Tokyo 180-8633 (Japan); Iida, N. [ULVAC-PHI, Inc., 370 Enzo, Chigasaki, Kanagawa 253-0084 (Japan); Yamamoto, A. [ULVAC-PHI, Inc., 370 Enzo, Chigasaki, Kanagawa 253-0084 (Japan); Kudo, M. [Department of Applied Physics, Faculty of Engineering, Seikei University, 3-3-1 Kichijioji-Kitamachi, Musashino-shi, Tokyo 180-8633 (Japan)

    2006-07-30

    We investigated the enhancement of the secondary ion intensity in the TOF-SIMS spectra obtained by Au{sup +} and Au{sub 3} {sup +} bombardment in comparison with Ga{sup +} excitation using polymer samples with different molecular weight distributions. Since the polymer samples used in this experiment have a wide molecular weight distribution, the advantages of the gold cluster primary ion source over monoatomic ion could accurately be evaluated. It was observed that the degree of fragmentation decreased by the usage of cluster primary ion beam compared with monoatomic ion beam, which was observed as a shift of the intensity distribution in the spectra. It was also found out that the mass effect of Au{sup +} and Ga{sup +} as monoatomic primary ion, resulted in about 10-60 times of enhancement for both samples with different molecular distributions. On the other hand, the Au{sub 3} {sup +} bombardment caused intensity enhancement about 100-2600 compared with Ga{sup +} bombardment, depending on the mass range of the detected secondary ion species. The cluster primary ion effect of Au{sub 3} {sup +}, compared with Au{sup +}, therefore, was estimated to be about 10-45.

  3. Summary of Industry-Academia Collaboration Projects on Cluster Ion Beam Process Technology

    International Nuclear Information System (INIS)

    Yamada, Isao; Toyoda, Noriaki; Matsuo, Jiro

    2008-01-01

    Processes employing clusters of ions comprised of a few hundred to many thousand atoms are now being developed into a new field of ion beam technology. Cluster-surface collisions produce important non-linear effects which are being applied to shallow junction formation, to etching and smoothing of semiconductors, metals, and dielectrics, to assisted formation of thin films with nano-scale accuracy, and to other surface modification applications. In 2000, a four year R and D project for development of industrial technology began in Japan under funding from the New Energy and Industrial Technology Development Organization (NEDO). Subjects of the projects are in areas of equipment development, semiconductor surface processing, high accuracy surface processing and high-quality film formation. In 2002, another major cluster ion beam project which emphasized nano-technology applications has started under a contract from the Ministry of Economy and Technology for Industry (METI). This METI project involved development related to size-selected cluster ion beam equipment and processes, and development of GCIB processes for very high rate etching and for zero damage etching of magnetic materials and compound semiconductor materials. This paper describes summery of the results.

  4. Structure and reactivity of molybdenum oxide cluster ions in the gas phase

    International Nuclear Information System (INIS)

    Goncharov, V.B.; Fialko, E.F.

    2002-01-01

    A set of cluster ions of molybdenum oxides Mo x O y + (x = 1-5, y = 1-15) was prepared using a combination of the ionic cyclotron resonance method and Knudsen effusion source. Dependence of concentration of different molybdenum oxide ions on the time of retention and their interaction with carbon monoxide was studied. It is shown that Mo x O y + ions with x>3 contain cyclic fragment Mo 3 O 9 in their structure. Oxygen binding energies within ionic clusters Mo x O y + were estimated [ru

  5. Pre-equilibrium (exciton) model and the heavy-ion reactions with cluster emission

    CERN Document Server

    Betak, E

    2015-01-01

    We bring the possibility to include the cluster emission into the statistical pre-equilibrium (exciton) model enlarged for considering also the heavy ion collisions. At this moment, the calculations have been done without treatment of angular momentum variables, but all the approach can be straightforwardly applied to heavy-ion reactions with cluster emission including the angular momentum variables. The direct motivation of this paper is a possibility of producing the superdeformed nuclei, which are easier to be detected in heavy-ion reactions than in those induced by light projectiles (nucleons, deuterons, $\\alpha$-particles).

  6. Confined SnO2 quantum-dot clusters in graphene sheets as high-performance anodes for lithium-ion batteries.

    Science.gov (United States)

    Zhu, Chengling; Zhu, Shenmin; Zhang, Kai; Hui, Zeyu; Pan, Hui; Chen, Zhixin; Li, Yao; Zhang, Di; Wang, Da-Wei

    2016-05-16

    Construction of metal oxide nanoparticles as anodes is of special interest for next-generation lithium-ion batteries. The main challenge lies in their rapid capacity fading caused by the structural degradation and instability of solid-electrolyte interphase (SEI) layer during charge/discharge process. Herein, we address these problems by constructing a novel-structured SnO2-based anode. The novel structure consists of mesoporous clusters of SnO2 quantum dots (SnO2 QDs), which are wrapped with reduced graphene oxide (RGO) sheets. The mesopores inside the clusters provide enough room for the expansion and contraction of SnO2 QDs during charge/discharge process while the integral structure of the clusters can be maintained. The wrapping RGO sheets act as electrolyte barrier and conductive reinforcement. When used as an anode, the resultant composite (MQDC-SnO2/RGO) shows an extremely high reversible capacity of 924 mAh g(-1) after 200 cycles at 100 mA g(-1), superior capacity retention (96%), and outstanding rate performance (505 mAh g(-1) after 1000 cycles at 1000 mA g(-1)). Importantly, the materials can be easily scaled up under mild conditions. Our findings pave a new way for the development of metal oxide towards enhanced lithium storage performance.

  7. Field Observation of the Green Ocean Amazon. Neutral Cluster Air Ion Spectrometer (NAIS) Final Campaign Summary

    Energy Technology Data Exchange (ETDEWEB)

    Petaja, T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Backman, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Manninen, H. E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wimmer, D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-01

    The neutral cluster and air ion spectrometer (NAIS) was deployed to the T3 site for Intensive Operations Periods 1 and 2 (IOP1 and IOP2). The NAIS is an instrument that measures aerosol particle and ion number size distributions in the mobility diameter range of 0.8 to 42 nm, corresponding to electrical mobility range between 3.2 and 0.0013 cm2 V-1 s-1. New particle formation (NPF) events were detected using the NAIS at the T3 field site during IOP1 and IOP2. Secondary NPF is a globally important source of aerosol number. To fully explain atmospheric NPF and subsequent growth, we need to directly measure the initial steps of the formation processes in different environments, including rain forest. Particle formation characteristics, such as formation and growth rates, were used as indicators of the relevant processes and participating compounds in the initial formation. In a case of parallel ion and neutral cluster measurements, we estimated the relative contribution of ion-induced and neutral nucleation to the total particle formation.

  8. Chemical probes of metal cluster structure--Fe, Co, Ni, and Cu

    International Nuclear Information System (INIS)

    Parks, E.K.; Zhu, L.; Ho, J.; Riley, S.J.

    1992-01-01

    Chemical reactivity is one of the few methods currently available for investigating the geometrical structure of isolated transition metal clusters. In this paper we summarize what is currently known about the structures of clusters of four transition metals, Fe, Co, Ni, and Cu, in the size range from 13 to 180 atoms. Chemical probes used to determine structural information include reactions with H 2 (D 2 ), H 2 0, NH 3 and N 2 . Measurements at both low coverage and at saturation are discussed

  9. The formation of magnetic silicide Fe{sub 3}Si clusters during ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Balakirev, N. [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Zhikharev, V., E-mail: valzhik@mail.ru [Kazan National Research Technological University, K.Marx st. 68, Kazan 420015 (Russian Federation); Gumarov, G. [Zavoiskii Physico-Technical Institute of Russian Academy of Sciences, 10/7 Sibirskii trakt st., Kazan 420029 (Russian Federation)

    2014-05-01

    A simple two-dimensional model of the formation of magnetic silicide Fe{sub 3}Si clusters during high-dose Fe ion implantation into silicon has been proposed and the cluster growth process has been computer simulated. The model takes into account the interaction between the cluster magnetization and magnetic moments of Fe atoms random walking in the implanted layer. If the clusters are formed in the presence of the external magnetic field parallel to the implanted layer, the model predicts the elongation of the growing cluster in the field direction. It has been proposed that the cluster elongation results in the uniaxial magnetic anisotropy in the plane of the implanted layer, which is observed in iron silicide films ion-beam synthesized in the external magnetic field.

  10. Ion irradiation effects in structural and magnetic properties of Co/Cu multilayers

    International Nuclear Information System (INIS)

    Sakamoto, Isao; Okazaki, Satoshi; Koike, Masaki; Honda, Shigeo

    2012-01-01

    400 keV Ar ion (the Ar ion) and 50 keV He ion (the He ion) irradiations were performed in order to elucidate roles of Co/Cu interfacial structures in physical origins of giant magnetoresistance (GMR) in the [Co (2 nm)/Cu (2 nm)] 30 multilayers (MLs). The magnetoresistance (MR) ratio after the Ar ion irradiation decreases abruptly with increasing Ar ion fluence. On the other hand, the MR ratio after the He ion irradiation decreases slowly with increasing He ion fluence. The Ar ion irradiation induces the decrease in the difference (R max − R sat ) between the maximum resistance (R max ) and the saturated resistance (R sat ) under in-plane magnetic field and the increase in the R sat , although the effect of the He ion irradiation is not remarkable. The decrease in the (R max − R sat ) rather than the increase in the R sat seems to be effective for the decrease in the MR ratios after the Ar ion and the He ion irradiation. The increase in the R sat implies the mixing of Co atoms in Cu layers. The antiferromagnetic coupling fraction (AFF) estimated from the magnetization curves after the Ar ion and the He ion irradiation shows the similar behavior with the MR ratio as a function of ion fluence. Therefore, although the degrees of the irradiation effects by the Ar ion and the He ions are different, we suggest the relation between the GMR and the AFF affected by the ion-induced interfacial structures accompanied with the atomic mixing in the interfacial region.

  11. a Web-Based Interactive Platform for Co-Clustering Spatio-Temporal Data

    Science.gov (United States)

    Wu, X.; Poorthuis, A.; Zurita-Milla, R.; Kraak, M.-J.

    2017-09-01

    Since current studies on clustering analysis mainly focus on exploring spatial or temporal patterns separately, a co-clustering algorithm is utilized in this study to enable the concurrent analysis of spatio-temporal patterns. To allow users to adopt and adapt the algorithm for their own analysis, it is integrated within the server side of an interactive web-based platform. The client side of the platform, running within any modern browser, is a graphical user interface (GUI) with multiple linked visualizations that facilitates the understanding, exploration and interpretation of the raw dataset and co-clustering results. Users can also upload their own datasets and adjust clustering parameters within the platform. To illustrate the use of this platform, an annual temperature dataset from 28 weather stations over 20 years in the Netherlands is used. After the dataset is loaded, it is visualized in a set of linked visualizations: a geographical map, a timeline and a heatmap. This aids the user in understanding the nature of their dataset and the appropriate selection of co-clustering parameters. Once the dataset is processed by the co-clustering algorithm, the results are visualized in the small multiples, a heatmap and a timeline to provide various views for better understanding and also further interpretation. Since the visualization and analysis are integrated in a seamless platform, the user can explore different sets of co-clustering parameters and instantly view the results in order to do iterative, exploratory data analysis. As such, this interactive web-based platform allows users to analyze spatio-temporal data using the co-clustering method and also helps the understanding of the results using multiple linked visualizations.

  12. Mobility and molecular ions of dimethyl methyl phosphonate, methyl salicylate and acetone

    Science.gov (United States)

    Nowak, D. M.

    1983-06-01

    The mobilities of positive and negative reactant ions are reported for (H2O)nH(+); (H2O)2O2 and (H2O)2CO3(-) ion clusters. The formation of positive DMMP monomer and dimer is reported, and equilbria molecular reactions are reported. Acetone is reported as forming a dimer at 81 ppb with a reduced mobility (K sub o) of 1.82, Methyl salicylate is shown to form a protonated and hydrated positive monomer. Mixtures of DMMP and methyl salicylate with acetone showed a substantial change in DMMP ion clustering and little or no change in the methyl salicylate mobility spectra. Negative ions were not observed for DMMP, methyl salicylate, acetone and the mixtures under the conditions reported.

  13. Theoretical investigation of CO adsorption on Rhn (n = 3-13) clusters

    NARCIS (Netherlands)

    Shetty, S.G.; Strych, S.; Jansen, A.P.J.; Santen, van R.A.

    2009-01-01

    The adsorption of CO onto Rhn (n = 3–13) clusters has been investigated using the density functional approach. Stable active sites for CO adsorption such as top, bridge, and hollow have been identified on these clusters. Our results show that CO mostly prefers the bridge or top site, except on the

  14. Plasma diagnostics of the SIMPA Ecr ion source by X-ray spectroscopy, Collisions of H-like Neon ions with Argon clusters

    International Nuclear Information System (INIS)

    Adrouche, N.

    2006-09-01

    The first part of this thesis is devoted to the SIMPA ECR ion source characterization, first, I explored the ion source's capacities on the point of view of extracted currents for three elements, argon, krypton and neon. By analyzing the Bremsstrahlung spectra, I determined the electronic temperature in the plasma and the electronic and ionic densities. In a second time, I recorded high resolution X-spectra of argon and krypton plasma's. By taking into account the principal mechanisms of production of a K hole in the ions inside the plasma, I determined the ionic densities of the high charge states of argon. Lastly, I highlighted a correlation between the ions charge states densities with the intensities of extracted currents. The second part of the thesis is devoted to Ne 9+- argon clusters collisions. First, I presented simple and effective theoretical models allowing to describe the phenomena occurring during a collision, from the point of view of the projectile. I carried out a simulation for a collision of an ion Ne 9+ with an argon cluster of a given size, which has enabled us to know the energy levels populated during the electronic capture and to follow the number of electrons in each projectile shell. Lastly, I presented the first results of a collision between a Ne 9+ beam and argon clusters. These results, have enabled me by using projectile X-ray spectroscopy during the ions-clusters collision, to evidence a strong clustering of targets atoms and to highlight an electronic multi-capture in the projectile ion excited states. (author)

  15. Synthesis and electrochemical properties of Co-doped Li3V2(PO4)3 cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Kuang Quan; Zhao Yanming; An Xiaoning; Liu Jianmin; Dong Youzhong; Chen Ling

    2010-01-01

    Co-doped Li 3 V 2-x Co x (PO 4 ) 3 /C (x = 0.00, 0.03, 0.05, 0.10, 0.13 or 0.15) compounds were prepared via a solid-state reaction. The Rietveld refinement results indicated that single-phase Li 3 V 2-x Co x (PO 4 ) 3 /C (0 ≤ x ≤ 0.15) with a monoclinic structure was obtained. The X-ray photoelectron spectroscopy (XPS) analysis revealed that the cobalt is present in the +2 oxidation state in Li 3 V 2-x Co x (PO 4 ) 3 . XPS studies also revealed that V 4+ and V 3+ ions were present in the Co 2+ -doped system. The initial specific capacity decreased as the Co-doping content increased, increasing monotonically with Co content for x > 0.10. Differential capacity curves of Li 3 V 2-x Co x (PO 4 ) 3 /C compounds showed that the voltage peaks associated with the extraction of three Li + ions shifted to higher voltages with an increase in Co content, and when the Co 2+ -doping content reached 0.15, the peak positions returned to those of the unsubstituted Li 3 V 2 (PO 4 ) 3 phase. For the Li 3 V 1.85 Co 0.15 (PO 4 ) 3 /C compound, the initial capacity was 163.3 mAh/g (109.4% of the initial capacity of the undoped Li 3 V 2 (PO 4 ) 3 ) and 73.4% capacity retention was observed after 50 cycles at a 0.1 C charge/discharge rate. The doping of Co 2+ into V sites should be favorable for the structural stability of Li 3 V 2-x Co x (PO 4 ) 3 /C compounds and so moderate the volume changes (expansion/contraction) seen during the reversible Li + extraction/insertion, thus resulting in the improvement of cell cycling ability.

  16. Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Maji, Siuli; Kumar, Satendra; Sankaran, Kannan [Indira Ghandi Centre for Atomic Research, Tamil Nadu (India). Materials Chemistry Div.

    2017-10-01

    Luminescence from UO{sub 2}{sup 2+} (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y{sup 3+}; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

  17. Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

    International Nuclear Information System (INIS)

    Maji, Siuli; Kumar, Satendra; Sankaran, Kannan

    2017-01-01

    Luminescence from UO_2"2"+ (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y"3"+; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

  18. Study of radicals, clusters and transition state species by anion photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Arnold, D.W.

    1994-08-01

    Free radicals, elemental and van der Waals clusters and transition state species for bimolecular chemical reactions are investigated using anion photoelectron spectroscopy. Several low-lying electronic states of ozone have been identified via photoelectron spectroscopy of O 3 - . A characterization of these states is important to models for atmospheric ozone reaction kinetics. The fluoroformyloxyl radical, FCO 2 , has been investigated, providing vibrational frequencies and energies for two electronic states. The technique has also been employed to make the first direct observation and characterization of the NNO 2 molecule. Several electronic states are observed for this species which is believed to play a role as a reactive intermediate in the N + NO 2 reaction. The experimental results for all three of these radicals are supplemented by ab initio investigations of their molecular properties. The clusters investigations include studies of elemental carbon clusters (C 2 - - C 11 - ), and van der Waals clusters (X - (CO 2 ) n , X = I, Br, Cl; n ≤ 13 and I - (N 2 O) n=1--11 ). Primarily linear clusters are observed for the smaller carbon clusters, while the spectra of the larger clusters contain contribution from cyclic anion photodetachment. Very interesting ion-solvent interactions are observed in the X - (CO 2 )n clusters. The transition state regions for several bimolecular chemical reactions have also been investigated by photodetachment of a negative ion precursor possessing a geometry similar to that of the transition state species. These spectra show features which are assigned to motions of the unstable neutral complex existing between reactants and products

  19. Proximity gettering technology for advanced CMOS image sensors using carbon cluster ion-implantation technique. A review

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Kazunari; Kadono, Takeshi; Okuyama, Ryousuke; Shigemastu, Satoshi; Hirose, Ryo; Onaka-Masada, Ayumi; Koga, Yoshihiro; Okuda, Hidehiko [SUMCO Corporation, Saga (Japan)

    2017-07-15

    A new technique is described for manufacturing advanced silicon wafers with the highest capability yet reported for gettering transition metallic, oxygen, and hydrogen impurities in CMOS image sensor fabrication processes. Carbon and hydrogen elements are localized in the projection range of the silicon wafer by implantation of ion clusters from a hydrocarbon molecular gas source. Furthermore, these wafers can getter oxygen impurities out-diffused to device active regions from a Czochralski grown silicon wafer substrate to the carbon cluster ion projection range during heat treatment. Therefore, they can reduce the formation of transition metals and oxygen-related defects in the device active regions and improve electrical performance characteristics, such as the dark current, white spot defects, pn-junction leakage current, and image lag characteristics. The new technique enables the formation of high-gettering-capability sinks for transition metals, oxygen, and hydrogen impurities under device active regions of CMOS image sensors. The wafers formed by this technique have the potential to significantly improve electrical devices performance characteristics in advanced CMOS image sensors. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Generation of H2 and CO by solar thermochemical splitting of H2O and CO2 by employing metal oxides

    International Nuclear Information System (INIS)

    Rao, C.N.R.; Dey, Sunita

    2016-01-01

    Generation of H 2 and CO by splitting H 2 O and CO 2 respectively constitutes an important aspect of the present-day concerns with energy and environment. The solar thermochemical route making use of metal oxides is a viable means of accomplishing these reduction reactions. The method essentially involves reducing a metal oxide by heating and passing H 2 O or CO 2 over the nonstoichiometric oxide to cause reverse oxidation by abstracting oxygen from H 2 O or CO 2 . While ceria, perovskites and other oxides have been investigated for this purpose, recent studies have demonstrated the superior performance of perovskites of the type Ln 1−x A x Mn 1−y M y O 3 (Ln=rare earth, A=alkaline earth, M=various +2 and +3 metal ions), in the thermochemical generation of H 2 and CO. We present the important results obtained hitherto to point out how the alkaine earth and the Ln ions, specially the radius of the latter, determine the performance of the perovskites. The encouraging results obtained are exemplefied by Y 0.5 Sr 0.5 MnO 3 which releases 483 µmol/g of O 2 at 1673 K and produces 757 µmol/g of CO from CO 2 at 1173 K. The production of H 2 from H 2 O is also quite appreciable. Modification of the B site ion of the perovskite also affects the performance. In addition to perovskites, we present the generation of H 2 based on the Mn 3 O 4 /NaMnO 2 cycle briefly. - Graphical abstract: Ln 0.5 A 0.5 Mn 1−x M x O 3 (Ln=lanthanide; A=Ca, Sr; M=Al, Ga, Sc, Mg, Cr, Fe, Co) perovskites are employed for the two step thermochemical splitting of CO 2 and H 2 O for the generation of CO and H 2 . - Highlights: • Perovskite oxides based on Mn are ideal for the two-step thermochemical splitting of CO 2 and H 2 O. • In Ln 1−x A x MnO 3 perovskite (Ln=rare earth, A=alkaline earth) both Ln and A ions play major roles in the thermochemical process. • H 2 O splitting is also achieved by the use of the Mn 3 O 4 -sodium carbonate system. • Thermochemical splitting of CO 2 and H

  1. Ion-streaming induced order transition in three-dimensional dust clusters

    International Nuclear Information System (INIS)

    Ludwig, Patrick; Kählert, Hanno; Bonitz, Michael

    2012-01-01

    Dust dynamics simulations utilizing a dynamical screening approach are performed to study the effect of ion-streaming on the self-organized structures in a three-dimensional spherically confined complex (dusty) plasma. Varying the Mach number M, the ratio of ion drift velocity to the sound velocity, the simulations reproduce the experimentally observed cluster configurations in the two limiting cases: at M = 0 strongly correlated crystalline structures consisting of nested spherical shells (Yukawa balls) and, for M ⩾ 1, flow-aligned dust chains, respectively. In addition, our simulations reveal a discontinuous transition between these two limits. It is found that already a moderate ion drift velocity (M ≈ 0.1 for the plasma conditions considered here) destabilizes the highly ordered Yukawa balls and initiates an abrupt melting transition. The critical value of M is found to be independent of the cluster size. (paper)

  2. Electrochemical behavior of LiCoO2 as aqueous lithium-ion battery electrodes

    KAUST Repository

    Ruffo, Riccardo

    2009-02-01

    Despite the large number of studies on the behavior of LiCoO2 in organic electrolytes and its recent application as a positive electrode in rechargeable water battery prototypes, a little information is available about the lithium intercalation reaction in this layered compound in aqueous electrolytes. This work shows that LiCoO2 electrodes can be reversibly cycled in LiNO3 aqueous electrolytes for tens of cycles at remarkably high rates with impressive values specific capacity higher than 100 mAh/g, and with a coulomb efficiency greater than 99.7%. Stable and reproducible cycling measurements have been made using a simple cell design that can be easily applied to the study of other intercalation materials, assuming that they are stable in water and that their intercalation potential range matches the electrochemical stability window of the aqueous electrolyte. The experimental arrangement uses a three-electrode flooded cell in which another insertion compound acts as a reversible source and sink of lithium ions, i.e., as the counter electrode. A commercial reference electrode is also present. Both the working and the counter electrodes have been prepared as thin layers on a metallic substrate using the procedures typical for the study of electrodes for lithium-ion batteries in organic solvent electrolytes. © 2008 Elsevier B.V. All rights reserved.

  3. Ultrathin Nanosheet Assembled Sn0.91 Co0.19 S2 Nanocages with Exposed (100) Facets for High-Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Li, Bing; Gu, Peng; Zhang, Guangxun; Lu, Yao; Huang, Kesheng; Xue, Huaiguo; Pang, Huan

    2018-02-01

    Ultrathin 2D inorganic nanomaterials are good candidates for lithium-ion batteries, as well as the micro/nanocage structures with unique and tunable morphologies. Meanwhile, as a cost-effective method, chemical doping plays a vital role in manipulating physical and chemical properties of metal oxides and sulfides. Thus, the design of ultrathin, hollow, and chemical doped metal sulfides shows great promise for the application of Li-ion batteries by shortening the diffusion pathway of Li ions as well as minimizing the electrode volume change. Herein, ultrathin nanosheet assembled Sn 0.91 Co 0.19 S 2 nanocages with exposed (100) facets are first synthesized. The as-prepared electrode delivers an excellent discharge capacity of 809 mA h g -1 at a current density of 100 mA g -1 with a 91% retention after 60 discharge-charge cycles. The electrochemical performance reveals that the Li-ion batteries prepared by Sn 0.91 Co 0.19 S 2 nanocages have high capacity and great cycling stability. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Effect of co-doping Tm3+ ions on the emission properties of Dy3+ ions in tellurite glasses

    International Nuclear Information System (INIS)

    Sasikala, T.; Rama Moorthy, L.; Mohan Babu, A.; Srinivasa Rao, T.

    2013-01-01

    The present work reports the absorption, photoluminescence and decay properties of singly doped Dy 3+ and co-doped Dy 3+ /Tm 3+ ions in TeO 2 +ZnO+K 2 O+CaO (TZKC) glasses prepared by the melt quenching technique. The glassy nature of the host glass has been confirmed by X-ray diffraction analysis and the primary vibrational modes were determined from the Raman spectrum. Judd–Ofelt (JO) analysis has been used to calculate the radiative transition rates, branching ratios and radiative lifetime of the emitting 4 F 9/2 state. The effect of co-doping of different concentrations of Tm 3+ ions on the emission properties of Dy 3+ ions has been investigated. The decay profiles of the 4 F 9/2 level were fitted to double exponential as well as Inokuti–Hirayama (IH) model to determine the energy transfer rates between Dy 3+ and Tm 3+ ions. The energy transfer rates found to increase with the increase of Tm 3+ ions concentration. The chromaticity coordinates and color purity of the emitted light for all glasses were determined. - Graphical abstract: The graphical abstract shows the emission spectra of Dy 3+ , Tm 3+ and Dy 3+ /Tm 3+ co-doped TZKC glasses recorded by exciting at 355 nm wavelength. - Highlights: • Zinc tellurite glasses doped with Dy 3+ , Tm 3+ and Dy 3+ /Tm 3+ ions were prepared. • XRD, DTA and Raman spectral measurements were recorded to know the nature of host. • Energy transfer occurs from Dy 3+ ions to Tm 3+ ions. • The color purity of the emitted light was determined

  5. Co_3V_2O_8 Hexagonal Pyramid with Tunable Inner Structure as High Performance Anode Materials for Lithium Ion Battery

    International Nuclear Information System (INIS)

    Zhang, Qiang; Pei, Jian; Chen, Gang; Bie, Changfeng; Chen, Dahong; Jiao, Yang; Rao, Jiancun

    2017-01-01

    Co_3V_2O_8 hexagonal pyramid was successfully fabricated via a simple hydrothermal process and subsequent heat treatment. The inner structure of the hexagonal pyramid was further adjusted by controlling the size of Co_7V_4O_1_6(OH)_2(H_2O) precursors. Hierarchical Co_3V_2O_8 hexagonal pyramid with height of 1 μm were orderly constructed from 60–80 nm inter-connected particles, showing numerous interval voids. Benefiting from its unique structure, the as-prepared sample showed higher electrochemical performance as an anode material for lithium-ion batteries than that of another bulk sample with height of 5 μm and adhesive inner structure. When tested at a current density of 500 mA g"−"1, the hierarchical Co_3V_2O_8 hexagonal pyramid exhibited good rate capacity, high cycling stability, and excellent discharge capacity up to 712 mA h g"−"1, making it promising electrode materials for lithium-ion batteries.

  6. Ab initio study of small He cluster ions Hen+, n=2, 3, 4, 5, and low-lying Rydberg states of He4

    International Nuclear Information System (INIS)

    Staemmler, V.

    1990-01-01

    SCF and CEPA calculations are applied to study the structure of small He cluster ions, He n 3 , n=2, 3, 4, 5 and some low-lying Rydberg states of He 4 . The effect of electron correlation upon the equilibrium structures and binding energies is discussed. He 3 + has a linear symmetric equilibrium geometry with a bond length of 2.35 a 0 and a binding energy D e =0.165 eV with respect to He 2 + +He (experimentally: D 0 =0.17 eV which corresponds to D e ≅0.20 eV). He 4 + is a very floppy molecular ion with several energetically very similar geometrical configurations. Our CEPA calculations yield a T-shaped form with a He 3 + centre (R e =2.35 a 0 ) and one inductively bound He atom (4.39 a 0 from the central He atom of He 3 + ) as equilibrium structure. Its binding energy with respect to He 3 + +He is 0.031 eV. A linear symmetric configuration consisting of a He 2 + centre with a bond length of 2.10 a 0 and two inductively bound He atoms (4.20 a 0 from the centre of He 2 + ) is only 0.02-0.03 eV higher in energy. We expect that in larger He cluster ions structures with He 2 + and He 3 + centres and n-2 or n-3 inductively bound He atoms have nearly the same energies. In He 4 a low-lying metastable Rydberg state ( 3 π symmetry for linear He 4 * , 3 B 1 for the T-shaped form) exists which is slightly stronger bound with respect to He 3 * +He than the corresponding ion. (orig.)

  7. Dynamics of Neutral Cluster Growth and Cluster Ion Fragmentation for Toluene/Water, Aniline/Argon, and 4-Fluorostyrene/Argon Clusters: Covariance Mapping of the Mass Spectral Data

    National Research Council Canada - National Science Library

    Foltin, M

    1998-01-01

    .... To explore sensitivity of the parent ion/fragment ion correlation coefficient to cluster fragmentation, correlation coefficients are measured as a function of ionization photon energy as thresholds...

  8. Co-clustering Analysis of Weblogs Using Bipartite Spectral Projection Approach

    DEFF Research Database (Denmark)

    Xu, Guandong; Zong, Yu; Dolog, Peter

    2010-01-01

    Web clustering is an approach for aggregating Web objects into various groups according to underlying relationships among them. Finding co-clusters of Web objects is an interesting topic in the context of Web usage mining, which is able to capture the underlying user navigational interest...... and content preference simultaneously. In this paper we will present an algorithm using bipartite spectral clustering to co-cluster Web users and pages. The usage data of users visiting Web sites is modeled as a bipartite graph and the spectral clustering is then applied to the graph representation of usage...... data. The proposed approach is evaluated by experiments performed on real datasets, and the impact of using various clustering algorithms is also investigated. Experimental results have demonstrated the employed method can effectively reveal the subset aggregates of Web users and pages which...

  9. Confined SnO2 quantum-dot clusters in graphene sheets as high-performance anodes for lithium-ion batteries

    Science.gov (United States)

    Zhu, Chengling; Zhu, Shenmin; Zhang, Kai; Hui, Zeyu; Pan, Hui; Chen, Zhixin; Li, Yao; Zhang, Di; Wang, Da-Wei

    2016-01-01

    Construction of metal oxide nanoparticles as anodes is of special interest for next-generation lithium-ion batteries. The main challenge lies in their rapid capacity fading caused by the structural degradation and instability of solid-electrolyte interphase (SEI) layer during charge/discharge process. Herein, we address these problems by constructing a novel-structured SnO2-based anode. The novel structure consists of mesoporous clusters of SnO2 quantum dots (SnO2 QDs), which are wrapped with reduced graphene oxide (RGO) sheets. The mesopores inside the clusters provide enough room for the expansion and contraction of SnO2 QDs during charge/discharge process while the integral structure of the clusters can be maintained. The wrapping RGO sheets act as electrolyte barrier and conductive reinforcement. When used as an anode, the resultant composite (MQDC-SnO2/RGO) shows an extremely high reversible capacity of 924 mAh g−1 after 200 cycles at 100 mA g−1, superior capacity retention (96%), and outstanding rate performance (505 mAh g−1 after 1000 cycles at 1000 mA g−1). Importantly, the materials can be easily scaled up under mild conditions. Our findings pave a new way for the development of metal oxide towards enhanced lithium storage performance. PMID:27181691

  10. Anisotropic Coulomb Explosion of CO Ligands in Group 6 Metal Hexacarbonyls: Cr(CO)6, Mo(CO)6, W(CO)6.

    Science.gov (United States)

    Tanaka, Hiroki; Nakashima, Nobuaki; Yatsuhashi, Tomoyuki

    2016-09-08

    Multiple ionization and subsequent Coulomb explosion have been studied for many organic molecules and their clusters; however, the metal complexes, particularly the large Coulombic interactions expected between a metal and its ligands, have not yet been explored. In this study, the angular distribution of CO(+), oxygen, and carbon ions ejected from metal hexacarbonyls (M(CO)6, M: Cr, Mo, W) having Oh symmetry by Coulomb explosion in femtosecond laser fields (>1 × 10(14) W cm(-2)) is investigated. The emissions of oxygen ions are well-explained in terms of the geometric alignment along a line inclined 45° relative to the CO-M-CO axis in a M(CO)4 plane. Unlike the explosion behavior of the oxygen ions located on the outer part of the molecule, the explosion behavior of the carbon ions was affected by the laser intensity, kinetic energy, and metal. This finding that the emission trends of carbon sandwiched between oxygen and metal atoms were the opposite of those for oxygen was explained by the obstruction by oxygen, the deformation of structure in bending coordinates, and the strong interaction with charged metal. The anisotropic Coulomb explosion of metal complexes reflecting their structural symmetry and central metal charge is a promising candidate for use in the investigation of large Coulombic interactions at the molecular level.

  11. Co-clustering directed graphs to discover asymmetries and directional communities.

    Science.gov (United States)

    Rohe, Karl; Qin, Tai; Yu, Bin

    2016-10-21

    In directed graphs, relationships are asymmetric and these asymmetries contain essential structural information about the graph. Directed relationships lead to a new type of clustering that is not feasible in undirected graphs. We propose a spectral co-clustering algorithm called di-sim for asymmetry discovery and directional clustering. A Stochastic co-Blockmodel is introduced to show favorable properties of di-sim To account for the sparse and highly heterogeneous nature of directed networks, di-sim uses the regularized graph Laplacian and projects the rows of the eigenvector matrix onto the sphere. A nodewise asymmetry score and di-sim are used to analyze the clustering asymmetries in the networks of Enron emails, political blogs, and the Caenorhabditis elegans chemical connectome. In each example, a subset of nodes have clustering asymmetries; these nodes send edges to one cluster, but receive edges from another cluster. Such nodes yield insightful information (e.g., communication bottlenecks) about directed networks, but are missed if the analysis ignores edge direction.

  12. ALMA reveals sunburn: CO dissociation around AGB stars in the globular cluster 47 Tucanae

    Science.gov (United States)

    McDonald, I.; Zijlstra, A. A.; Lagadec, E.; Sloan, G. C.; Boyer, M. L.; Matsuura, M.; Smith, R. J.; Smith, C. L.; Yates, J. A.; van Loon, J. Th.; Jones, O. C.; Ramstedt, S.; Avison, A.; Justtanont, K.; Olofsson, H.; Blommaert, J. A. D. L.; Goldman, S. R.; Groenewegen, M. A. T.

    2015-11-01

    Atacama Large Millimetre Array observations show a non-detection of carbon monoxide around the four most luminous asymptotic giant branch (AGB) stars in the globular cluster 47 Tucanae. Stellar evolution models and star counts show that the mass-loss rates from these stars should be ˜1.2-3.5 × 10-7 M⊙ yr-1. We would naïvely expect such stars to be detectable at this distance (4.5 kpc). By modelling the ultraviolet radiation field from post-AGB stars and white dwarfs in 47 Tuc, we conclude that CO should be dissociated abnormally close to the stars. We estimate that the CO envelopes will be truncated at a few hundred stellar radii from their host stars and that the line intensities are about two orders of magnitude below our current detection limits. The truncation of CO envelopes should be important for AGB stars in dense clusters. Observing the CO (3-2) and higher transitions and targeting stars far from the centres of clusters should result in the detections needed to measure the outflow velocities from these stars.

  13. Heavy-ion induced desorption yields of cryogenic surfaces bombarded with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Evans, L; Kollmus, H; Küchler, D; Scrivens, R; Severin, D; Wengenroth, M; CERN. Geneva. ATS Department

    2011-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy-Ion Accelerator LINAC 3, has been used to study the dynamic outgassing of cryogenic surfaces. Two different targets, bare and goldcoated copper, were bombarded under perpendicular impact with 4.2 MeV/u Pb54+ ions. Partial pressure rises of H2, CH4, CO, and CO2 and effective desorption yields were measured at 300, 77, and 6.3 K using single shot and continuous ion bombardment techniques. We find that the heavy-ion-induced desorption yield is temperature dependent and investigate the influence of CO gas cryosorbed at 6.3 K. The gain in desorption yield reduction at cryogenic temperature vanishes after several monolayers of CO are cryosorbed on both targets. In this paper we describe the new cryogenic target assembly, the temperature-dependent pressure rise, desorption yield, and gas adsorption measurements.

  14. Pseudo-solid-solution CuCo2O4/C nanofibers as excellent anodes for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhang, Hang; Tang, Zhiyong; Zhang, Kang; Wang, Lei; Shi, Huimin; Zhang, Guanhua; Duan, Huigao

    2017-01-01

    Ternary transition metal oxides have received intense research interest as electrode materials for lithium ion batteries, due to their high specific capacity originating from the synergic effects of multiple metal active sites. Reducing the size of metal oxides nanoparticles and dispersing these nanoparticles in carbon matrix are considering effective strategies to improve the electrochemical performance of transition metal oxides. Ternary CuCo 2 O 4 nanoclusters ultra-uniformly dispersed in carbon nanofiber matrix forming a pseudo-solid-solution structure are successfully synthesized by a facile electrospinning method followed by an appropriate annealing process. As the anodic electrode for lithium ion batteries, the pseudo-solid-solution CuCo 2 O 4 /C electrode exhibits a high reversible specific capacity, improved rate capacity and excellent cycling stability. A discharge capacity of 865 mAh g −1 is obtained at the current density of 200 mA g −1 after 400 cycles. Surprisingly, the electrode still retains about 610 mAh g −1 after 800 cycles even at the current density of 600 mA g −1 . The superior lithium storage performance of the pseudo-solid-solution CuCo 2 O 4 /C composites is mainly attributed to the unique amorphous structure. The ultrafine CuCo 2 O 4 nanoclusters uniformly dispersed in carbon matrix can buffer the volume change and improve the conductivity of the metal oxide based electrode, guaranteeing the structure stability and fast electron transfer.

  15. Collision-Induced Dissociation Study of Strong Hydrogen-Bonded Cluster Ions Y-(HF) n (Y=F, O2) Using Atmospheric Pressure Corona Discharge Ionization Mass Spectrometry Combined with a HF Generator.

    Science.gov (United States)

    Sakamoto, Kenya; Sekimoto, Kanako; Takayama, Mitsuo

    2017-01-01

    Hydrogen fluoride (HF) was produced by a homemade HF generator in order to investigate the properties of strong hydrogen-bonded clusters such as (HF) n . The HF molecules were ionized in the form of complex ions associated with the negative core ions Y - produced by atmospheric pressure corona discharge ionization (APCDI). The use of APCDI in combination with the homemade HF generator led to the formation of negative-ion HF clusters Y - (HF) n (Y=F, O 2 ), where larger clusters with n ≥4 were not detected. The mechanisms for the formation of the HF, F - (HF) n , and O 2 - (HF) n species were discussed from the standpoints of the HF generator and APCDI MS. By performing energy-resolved collision-induced dissociation (CID) experiments on the cluster ions F - (HF) n ( n =1-3), the energies for the loss of HF from F - (HF) 3 , F - (HF) 2 , and F - (HF) were evaluated to be 1 eV or lower, 1 eV or higher, and 2 eV, respectively, on the basis of their center-of-mass energy ( E CM ). These E CM values were consistent with the values of 0.995, 1.308, and 2.048 eV, respectively, obtained by ab initio calculations. The stability of [O 2 (HF) n ] - ( n =1-4) was discussed on the basis of the bond lengths of O 2 H-F - (HF) n and O 2 - H-F(HF) n obtained by ab initio calculations. The calculations indicated that [O 2 (HF) 4 ] - separated into O 2 H and F - (HF) 3 .

  16. Evaluation of CNTs/MnO{sub 2} composite for adsorption of {sup 60}Co(II), {sup 65}Zn(II) and Cd(II) ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sharaf El-Deen, Sahar E.A.; Moussa, Saber I.; Mekawy, Zakaria A.; Shehata, Mohamed K.K.; Someda, Hanan H. [Atomic Energy Authority, Inshas (Egypt). Dept. of Nuclear Chemistry; Sadeek, Sadeek A. [Zagazig Univ. (Egypt). Dept. of Chemistry

    2017-03-01

    CNTs/MnO{sub 2} composite was synthesized by a co-precipitation method after preparation of carbon nanotubes (CNTs) using a chemical oxidation method and was characterized using Fourier transformer infrared (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The synthesized CNTs/MnO{sub 2} composite was used as a sorbent for the removal of some radionuclides ({sup 60}Co and {sup 65}Zn-radioisotopes) and Cd (II) ions from aqueous solutions. Different parameters affecting the removal process including pH, contact time and metal ion concentration were investigated. Isotherm and kinetic models were studied. Adsorption data was interpreted in terms of both Freundlich and Langmuir isotherms and indicated that the CNTs/MnO{sub 2} composite complied well with both Langmuir and Freundlich models for {sup 60}Co and Cd(II) ions and with the Freundlich model only for the {sup 65}Zn radioisotope. A pseudo-second-order model was effectively employed to describe the adsorption behavior of {sup 60}Co, {sup 65}Zn and Cd(II) ions. Desorption of {sup 60}Co and {sup 65}Zn and Cd(II) ions from loaded samples was studied using different eluents.

  17. Characteristics and properties of nano-LiCoO2 synthesized by pre-organized single source precursors: Li-ion diffusivity, electrochemistry and biological assessment.

    Science.gov (United States)

    Brog, Jean-Pierre; Crochet, Aurélien; Seydoux, Joël; Clift, Martin J D; Baichette, Benoît; Maharajan, Sivarajakumar; Barosova, Hana; Brodard, Pierre; Spodaryk, Mariana; Züttel, Andreas; Rothen-Rutishauser, Barbara; Kwon, Nam Hee; Fromm, Katharina M

    2017-08-22

    LiCoO 2 is one of the most used cathode materials in Li-ion batteries. Its conventional synthesis requires high temperature (>800 °C) and long heating time (>24 h) to obtain the micronscale rhombohedral layered high-temperature phase of LiCoO 2 (HT-LCO). Nanoscale HT-LCO is of interest to improve the battery performance as the lithium (Li + ) ion pathway is expected to be shorter in nanoparticles as compared to micron sized ones. Since batteries typically get recycled, the exposure to nanoparticles during this process needs to be evaluated. Several new single source precursors containing lithium (Li + ) and cobalt (Co 2+ ) ions, based on alkoxides and aryloxides have been structurally characterized and were thermally transformed into nanoscale HT-LCO at 450 °C within few hours. The size of the nanoparticles depends on the precursor, determining the electrochemical performance. The Li-ion diffusion coefficients of our LiCoO 2 nanoparticles improved at least by a factor of 10 compared to commercial one, while showing good reversibility upon charging and discharging. The hazard of occupational exposure to nanoparticles during battery recycling was investigated with an in vitro multicellular lung model. Our heterobimetallic single source precursors allow to dramatically reduce the production temperature and time for HT-LCO. The obtained nanoparticles of LiCoO 2 have faster kinetics for Li + insertion/extraction compared to microparticles. Overall, nano-sized LiCoO 2 particles indicate a lower cytotoxic and (pro-)inflammogenic potential in vitro compared to their micron-sized counterparts. However, nanoparticles aggregate in air and behave partially like microparticles.

  18. Recycling of cobalt from spent Li-ion batteries as β-Co(OH)2 and the application of Co3O4 as a pseudocapacitor

    Science.gov (United States)

    Barbieri, E. M. S.; Lima, E. P. C.; Lelis, M. F. F.; Freitas, M. B. J. G.

    2014-12-01

    This work has investigated recycling cobalt from the cathodes of spent Li-ion batteries as β-Co(OH)2, obtaining Co3O4. β-Co(OH)2 with a hexagonal structure by using chemical precipitation (CP) or electrochemical precipitation (EP). In addition, the study has investigated whether the charge density applied directly affects the β-Co(OH)2 morphology. Co3O4 is formed by heat-treating β-Co(OH)2 at 450 °C for 3 h (h) in an air atmosphere. After calcining, the Co3O4 shows a cubic structure and satisfactory purity grade, regardless of the route used for preparation via which it was obtained. Cyclic voltammetry (CV) is then used for electrochemical characterization of the Co3O4 composite electrodes. In the cathodic process, CoO2 undergoes reduction to CoOOH, which undergoes further reduction to Co3O4. In the anodic process, Co3O4 undergoes oxidation to CoOOH, which simultaneously undergoes further oxidation to CoO2. The composite electrodes containing Co3O4, carbon black, and epoxy resin show great reversibility, charge efficiency, and a specific capacitance of 13.0 F g-1 (1.0 mV s-1). The synthesis method of Co(OH)2 influences the charge efficiency of Co3O4 composite electrodes at a scan rate of 10.0 mV s-1. Therefore, in addition to presenting an alternative use for exhausted batteries, Co3O4 composites exhibit favorable characteristics for use as pseudocapacitors.

  19. Cobalt Coordination and Clustering in α-Co(OH)2 Revealed by Synchrotron X-ray Total Scattering

    International Nuclear Information System (INIS)

    Neilson, James R.; Kurzman, Joshua A.; Seshadri, Ram; Morse, Daniel E.

    2010-01-01

    Structures of layered metal hydroxides are not well described by traditional crystallography. Total scattering from a synthesis-controlled subset of these materials, as described here, reveals that different cobalt coordination polyhedra cluster within each layer on short length scales, offering new insights and approaches for understanding the properties of these and related layered materials. Structures related to that of brucite (Mg(OH) 2 ) are ubiquitous in the mineral world and offer a variety of useful functions ranging from catalysis and ion-exchange to sequestration and energy transduction, including applications in batteries. However, it has been difficult to resolve the atomic structure of these layered compounds because interlayer disorder disrupts the long-range periodicity necessary for diffraction-based structure determination. For this reason, traditional unit-cell-based descriptions have remained inaccurate. Here we apply, for the first time to such layered hydroxides, synchrotron X-ray total scattering methods - analyzing both the Bragg and diffuse components - to resolve the intralayer structure of three different α-cobalt hydroxides, revealing the nature and distribution of metal site coordination. The different compounds with incorporated chloride ions have been prepared with kinetic control of hydrolysis to yield different ratios of octahedrally and tetrahedrally coordinated cobalt ions within the layers, as confirmed by total scattering. Real-space analyses indicate local clustering of polyhedra within the layers, manifested in the weighted average of different ordered phases with fixed fractions of tetrahedrally coordinated cobalt sites. These results, hidden from an averaged unit-cell description, reveal new structural characteristics that are essential to understanding the origin of fundamental material properties such as color, anion exchange capacity, and magnetic behavior. Our results also provide further insights into the detailed

  20. Cobalt coordination and clustering in alpha-Co(OH)(2) revealed by synchrotron X-ray total scattering.

    Science.gov (United States)

    Neilson, James R; Kurzman, Joshua A; Seshadri, Ram; Morse, Daniel E

    2010-09-03

    Structures of layered metal hydroxides are not well described by traditional crystallography. Total scattering from a synthesis-controlled subset of these materials, as described here, reveals that different cobalt coordination polyhedra cluster within each layer on short length scales, offering new insights and approaches for understanding the properties of these and related layered materials. Structures related to that of brucite [Mg(OH)(2)] are ubiquitous in the mineral world and offer a variety of useful functions ranging from catalysis and ion-exchange to sequestration and energy transduction, including applications in batteries. However, it has been difficult to resolve the atomic structure of these layered compounds because interlayer disorder disrupts the long-range periodicity necessary for diffraction-based structure determination. For this reason, traditional unit-cell-based descriptions have remained inaccurate. Here we apply, for the first time to such layered hydroxides, synchrotron X-ray total scattering methods-analyzing both the Bragg and diffuse components-to resolve the intralayer structure of three different alpha-cobalt hydroxides, revealing the nature and distribution of metal site coordination. The different compounds with incorporated chloride ions have been prepared with kinetic control of hydrolysis to yield different ratios of octahedrally and tetrahedrally coordinated cobalt ions within the layers, as confirmed by total scattering. Real-space analyses indicate local clustering of polyhedra within the layers, manifested in the weighted average of different ordered phases with fixed fractions of tetrahedrally coordinated cobalt sites. These results, hidden from an averaged unit-cell description, reveal new structural characteristics that are essential to understanding the origin of fundamental material properties such as color, anion exchange capacity, and magnetic behavior. Our results also provide further insights into the detailed

  1. Fast sodium ion conductivity in supertetrahedral phosphidosilicates.

    Science.gov (United States)

    Johrendt, Dirk; Haffner, Arthur; Hatz, Anna Katharina; Moudrakovski, Igor; Lotsch, Bettina Valeska

    2018-04-03

    Fast sodium ion conductors are key components of sodium-based all-solid-state batteries which hold promise as safe systems for large-scale storage of electrical power. Here, we report the synthesis, crystal structure determination and Na+ ion conductivities of six new sodium ion conductors, the phosphidosilicates Na19Si13P25, Na23Si19P33, Na23Si28P45, Na23Si37P57, LT-NaSi2P3 and HT-NaSi2P3, which are entirely based on earth-abundant elements. The new structures exhibit SiP4 tetrahedra assembling interpenetrating networks of T3 to T5 supertetrahedral clusters which can be hierarchically assigned to sphalerite- or diamond-type structures. 23Na solid-state NMR spectra and geometrical pathway analysis indicate Na+ ion mobility between the supertetrahedral cluster networks. Electrochemical impedance spectroscopy revealed Na+ ion conductivities up to σ (Na+) = 4 ∙ 10-4 Scm-1 with an activation energy of Ea = 0.25 eV in HT-NaSi2P3 at 25 °C. The conductivities increase with the size of the supertetrahedral clusters due to the dilution of Na+ ions as the charge density of the anionic supertetrahedral networks decreases. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Enhancement in anomalous Hall resistivity of Co/Pd multilayer and CoPd alloy by Ga+ ion irradiation

    KAUST Repository

    Guo, Zaibing; Mi, Wenbo; Li, Jingqi; Cheng, Yingchun; Zhang, Xixiang

    2014-01-01

    /Pd multilayer and CoPd alloy have been observed after irradiations at doses of 2.4 × 1015 and 3.3×10 15 ions/cm2, respectively. Skew scattering and side jump contributions to AHE have been analyzed based on the scaling relationship ρAH = aρxx + bρ2xx. For the Co

  3. Absolute single-ion solvation free energy scale in methanol determined by the lithium cluster-continuum approach.

    Science.gov (United States)

    Pliego, Josefredo R; Miguel, Elizabeth L M

    2013-05-02

    Absolute solvation free energy of the lithium cation in methanol was calculated by the cluster-continuum quasichemical theory of solvation. Clusters with up to five methanol molecules were investigated using X3LYP, MP2, and MP4 methods with DZVP, 6-311+G(2df,2p), TZVPP+diff, and QZVPP+diff basis sets and including the cluster solvation through the PCM and SMD continuum models. Our calculations have determined a value of -118.1 kcal mol(-1) for the solvation free energy of the lithium, in close agreement with a value of -116.6 kcal mol(-1) consistent with the TATB assumption. Using data of solvation and transfer free energy of a pair of ions, electrode potentials and pKa, we have obtained the solvation free energy of 25 ions in methanol. Our analysis leads to a value of -253.6 kcal mol(-1) for the solvation free energy of the proton, which can be compared with the value of -263.5 kcal mol(-1) obtained by Kelly et al. using the cluster pair approximation. Considering that this difference is due to the methanol surface potential, we have estimated that it corresponds to -0.429 V.

  4. Low temperature growth of Co{sub 2}MnSi films on diamond semiconductors by ion-beam assisted sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Nishiwaki, M.; Ueda, K., E-mail: k-ueda@numse.nagoya-u.ac.jp; Asano, H. [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-05-07

    High quality Schottky junctions using Co{sub 2}MnSi/diamond heterostructures were fabricated. Low temperature growth at ∼300–400 °C by using ion-beam assisted sputtering (IBAS) was necessary to obtain abrupt Co{sub 2}MnSi/diamond interfaces. Only the Co{sub 2}MnSi films formed at ∼300–400 °C showed both saturation magnetization comparable to the bulk values and large negative anisotropic magnetoresistance, which suggests half-metallic nature of the Co{sub 2}MnSi films, of ∼0.3% at 10 K. Schottky junctions formed using the Co{sub 2}MnSi films showed clear rectification properties with rectification ratio of more than 10{sup 7} with Schottky barrier heights of ∼0.8 eV and ideality factors (n) of ∼1.2. These results indicate that Co{sub 2}MnSi films formed at ∼300–400 °C by IBAS are a promising spin source for spin injection into diamond semiconductors.

  5. Solar wind dependence of ion parameters in the Earth's magnetospheric region calculated from CLUSTER observations

    Directory of Open Access Journals (Sweden)

    M. H. Denton

    2008-03-01

    Full Text Available Moments calculated from the ion distributions (~0–40 keV measured by the Cluster Ion Spectrometry (CIS instrument are combined with data from the Cluster Flux Gate Magnetometer (FGM instrument and used to characterise the bulk properties of the plasma in the near-Earth magnetosphere over five years (2001–2005. Results are presented in the form of 2-D xy, xz and yz GSM cuts through the magnetosphere using data obtained from the Cluster Science Data System (CSDS and the Cluster Active Archive (CAA. Analysis reveals the distribution of ~0–40 keV ions in the inner magnetosphere is highly ordered and highly responsive to changes in solar wind velocity. Specifically, elevations in temperature are found to occur across the entire nightside plasma sheet region during times of fast solar wind. We demonstrate that the nightside plasma sheet ion temperature at a downtail distance of ~12 to 19 Earth radii increases by a factor of ~2 during periods of fast solar wind (500–1000 km s−1 compared to periods of slow solar wind (100–400 km s−1. The spatial extent of these increases are shown in the xy, xz and yz GSM planes. The results from the study have implications for modelling studies and simulations of solar-wind/magnetosphere coupling, which ultimately rely on in situ observations of the plasma sheet properties for input/boundary conditions.

  6. Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation

    Directory of Open Access Journals (Sweden)

    Ricardo Couto

    2015-01-01

    Full Text Available In this work, a supported ionic liquid membrane (SILM was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA] ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2 and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73 for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids.

  7. Moessbauer spectroscopic determination of magnetic moments of Fe3+ and Co2+ in substituted barium hexaferrite, Ba(Co,Ti)xFe(12-2x)O19

    International Nuclear Information System (INIS)

    Williams, J.M.; Adetunji, J.; Gregori, M.

    2000-01-01

    We report the distribution of magnetic moments of Fe 3+ and Co 2+ in Co 2+ -, Ti 4+ -substituted M-type barium hexaferrite, Ba(Co,Ti) x Fe (12-2x) O 19 , as a function of doping rate, x. The substitution, x, for iron has been varied with x=0, 0.25, 0.50, 0.70 and 0.85. The magnetic moments of Fe 3+ and Co 2+ were calculated from the combined results of Moessbauer measurements for Fe 3+ ions in the sublattices and neutron diffraction data for the total moments of Fe 3+ and Co 2+ . A comparison of the signs of the magnetic moments of Fe 3+ and Co 2+ ions enabled us to attribute spin directions of the Co 2+ ions in the sublattices of the substituted ferrite samples. The spin directions of Co 2+ are opposite to those of Fe 3+ in the 4f 2 and 2b sublattices. They are reversed from the original directions in the 4f 1 and 12K sublattices when the value of x≥0.70. A quantitative analysis shows that Co 2+ and Ti 4+ ions are preferably substituted into 4f 2 and 12K sublattices, respectively. In addition, while the hyperfine field of Fe 3+ in the 2b sublattice gives rise to the 2b-4f 2 interaction it is the partially substituted Co 2+ ions in the 4f 1 and 12K sublattices that contribute to the near neighbour 2a-4f 1 and 2b-12K types of interaction

  8. Ion beam induced modification of exchange interaction and spin-orbit coupling in the Co2FeSi Heusler compound

    International Nuclear Information System (INIS)

    Hamrle, J; Blomeier, S; Gaier, O; Hillebrands, B; Schneider, H; Jakob, G; Reuscher, B; Brodyanski, A; Kopnarski, M; Postava, K; Felser, C

    2007-01-01

    A Co 2 FeSi (CFS) film with L2 1 structure was irradiated with different fluences of 30 keV Ga + ions. Structural modifications were subsequently studied using the longitudinal (LMOKE) and quadratic (QMOKE) magneto-optical Kerr effect. Both the coercivity and the LMOKE amplitude were found to show a similar behaviour upon irradiation: they are nearly constant up to ion fluences of ∼6 x 10 15 ion cm -2 , while they decrease with further increasing fluences and finally vanish at a fluence of ∼9 x 10 16 ion cm -2 , when the sample becomes paramagnetic. However, contrary to this behaviour, the QMOKE signal nearly vanishes even for the smallest applied fluence of 3 x 10 14 ion cm -2 . We attribute this reduction of the QMOKE signal to an irradiation-induced degeneration of second or higher order spin-orbit coupling, which already happens at small fluences of 30 keV Ga + ions. On the other hand, the reduction of coercivity and LMOKE signal with high ion fluences is probably caused by a reduction of the exchange interaction within the film material

  9. Visualization of complex DNA damage along accelerated ions tracks

    Science.gov (United States)

    Kulikova, Elena; Boreyko, Alla; Bulanova, Tatiana; Ježková, Lucie; Zadneprianetc, Mariia; Smirnova, Elena

    2018-04-01

    The most deleterious DNA lesions induced by ionizing radiation are clustered DNA double-strand breaks (DSB). Clustered or complex DNA damage is a combination of a few simple lesions (single-strand breaks, base damage etc.) within one or two DNA helix turns. It is known that yield of complex DNA lesions increases with increasing linear energy transfer (LET) of radiation. For investigation of the induction and repair of complex DNA lesions, human fibroblasts were irradiated with high-LET 15N ions (LET = 183.3 keV/μm, E = 13MeV/n) and low-LET 60Co γ-rays (LET ≈ 0.3 keV/μm) radiation. DNA DSBs (γH2AX and 53BP1) and base damage (OGG1) markers were visualized by immunofluorecence staining and high-resolution microscopy. The obtained results showed slower repair kinetics of induced DSBs in cells irradiated with accelerated ions compared to 60Co γ-rays, indicating induction of more complex DNA damage. Confirming previous assumptions, detailed 3D analysis of γH2AX/53BP1 foci in 15N ions tracks revealed more complicated structure of the foci in contrast to γ-rays. It was shown that proteins 53BP1 and OGG1 involved in repair of DNA DSBs and modified bases, respectively, were colocalized in tracks of 15N ions and thus represented clustered DNA DSBs.

  10. A Au82Si18 liquid metal field-ion emitter for the production of Si ions: fundamental properties and mechanisms

    International Nuclear Information System (INIS)

    Bischoff, L.; Mair, G.L.R.; Aidinis, C.J.; Londos, C.A.; Akhmadaliev, C.; Ganetsos, Th.

    2004-01-01

    Focused silicon beams are useful for direct write applications, e.g., lithography on silicon without the undesirable effect of substrate contamination. However, since pure silicon is not amenable to liquid metal ion source (LMIS) manufacture, a suitable alloy containing silicon has to be produced. This paper covers almost all fundamental aspects of a Au 82 Si 18 eutectic, including the most detailed beam mass spectra reported to date of a AuSi source. A finding worthy of note in this investigation, manifested in the behaviour of the ion extraction voltage with temperature, is the abnormal behaviour of the surface tension coefficient of the alloy with temperature. An important deduction from this work, however, concerns the mechanisms responsible for the creation of doubly charged ions: reasons of self-consistency indicate that while Si 2+ is directly field evaporated, Au 2+ must form by the post-ionization of Au + . Finally, two different mechanisms seem to co-exist, as far as the production of cluster ions is concerned. While for cluster ions containing only a few atoms some sort of surface field-ionization mechanism might be responsible for their creation, for larger clusters, a droplet break-up mechanism, possibly by ion capture, seems very likely

  11. Enhanced Magnetization of Cobalt Defect Clusters Embedded in TiO2-δ Films.

    Science.gov (United States)

    Cortie, David L; Khaydukov, Yury; Keller, Thomas; Sprouster, David J; Hughes, Jacob S; Sullivan, James P; Wang, Xiaolin L; Le Brun, Anton P; Bertinshaw, Joel; Callori, Sara J; Aughterson, Robert; James, Michael; Evans, Peter J; Triani, Gerry; Klose, Frank

    2017-03-15

    High magnetizations are desirable for spintronic devices that operate by manipulating electronic states using built-in magnetic fields. However, the magnetic moment in promising dilute magnetic oxide nanocomposites is very low, typically corresponding to only fractions of a Bohr magneton for each dopant atom. In this study, we report a large magnetization formed by ion implantation of Co into amorphous TiO 2-δ films, producing an inhomogeneous magnetic moment, with certain regions producing over 2.5 μ B per Co, depending on the local dopant concentration. Polarized neutron reflectometry was used to depth-profile the magnetization in the Co:TiO 2-δ nanocomposites, thus confirming the pivotal role of the cobalt dopant profile inside the titania layer. X-ray photoemission spectra demonstrate the dominant electronic state of the implanted species is Co 0 , with a minor fraction of Co 2+ . The detected magnetizations have seldom been reported before and lie near the upper limit set by Hund's rules for Co 0 , which is unusual because the transition metal's magnetic moment is usually reduced in a symmetric 3D crystal-field environment. Low-energy positron annihilation lifetime spectroscopy indicates that defect structures within the titania layer are strongly modified by the implanted Co. We propose that a clustering motif is promoted by the affinity of the positively charged implanted species to occupy microvoids native to the amorphous host. This provides a seed for subsequent doping and nucleation of nanoclusters within an unusual local environment.

  12. Enhanced Magnetization of Cobalt Defect Clusters Embedded in TiO_2_-_δ Films

    International Nuclear Information System (INIS)

    Cortie, David L.; Khaydukov, Yury; Max Planck Society, Garching

    2017-01-01

    High magnetizations are desirable for spintronic devices that operate by manipulating electronic states using built-in magnetic fields. However, the magnetic moment in promising dilute magnetic oxide nanocomposites is very low, typically corresponding to only fractions of a Bohr magneton for each dopant atom. In this study, we report a large magnetization formed by ion implantation of Co into amorphous TiO_2_-_δ films, producing an inhomogeneous magnetic moment, with certain regions producing over 2.5 μ_B per Co, depending on the local dopant concentration. Polarized neutron reflectometry was used to depth-profile the magnetization in the Co:TiO_2_-_δ nanocomposites, thus confirming the pivotal role of the cobalt dopant profile inside the titania layer. X-ray photoemission spectra demonstrate the dominant electronic state of the implanted species is Co"0, with a minor fraction of Co"2"+. The detected magnetizations have seldom been reported before and lie near the upper limit set by Hund’s rules for Co"0, which is unusual because the transition metal’s magnetic moment is usually reduced in a symmetric 3D crystal-field environment. Low-energy positron annihilation lifetime spectroscopy indicates that defect structures within the titania layer are strongly modified by the implanted Co. We propose that a clustering motif is promoted by the affinity of the positively charged implanted species to occupy microvoids native to the amorphous host. This provides a seed for subsequent doping and nucleation of nanoclusters within an unusual local environment.

  13. Respective efficiencies of nuclear collisions and electronic excitations for precipitating Ag clusters in sol-gel films

    CERN Document Server

    Pivin, J C

    2002-01-01

    The growth of silver clusters in co-sputtered SiO sub 2 :Ag films under irradiation with increasing fluences of 1.5 MeV He or 3 MeV Au ions is investigated by recording spectra of optical extinction. The analysis of surface plasmon resonances in these very small clusters on basis of Mie theory permits to estimate more precisely their mean size than TEM images. A linear increase of the mean cluster size with the energy deposited by ions in electronic excitations and little effect of collision cascades are observed. The growth kinetics is ascribed to a process of desorption/re-adsorption of Ag atoms at the surface of clusters.

  14. Molecular dynamic simulation of interaction of low-energy Ar and Xe ions with copper clusters at graphite surface

    International Nuclear Information System (INIS)

    Kornich, G.V.; Lozovskaya, L.I.; Betts, G.; Zaporozhchenko, V.I.; Faupel, F.

    2005-01-01

    One conducted molecular and dynamic simulation of sputtering of isolated clusters consisting of 13, 27 and 195 Cu atoms from the (0001) graphite surface by 200 eV energy Ar and Xe ions. It is shown that the factors of reflection of Ar and Xe ions from copper clusters differ from one another insignificantly, though the energy of the reflected Xe ions is essentially lower than that of Ar ions. The values of the factor of cluster sputtering by Xe ions are higher in contrast to sputtering by Ar ions. One identified two mechanisms of cluster sputtering resulting in the maximum of sputtering intensity at the polar angles near the normal one, and in periodicity of maximums within the azimuth distributions of sputtering intensity with 60 deg period [ru

  15. Effect of Co{sup 2+} and Y{sup 3+} ions insertion on the microstructure development and magnetic properties of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} powders synthesized using Co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Rashad, M.M., E-mail: rashad133@yahoo.com [Central Metallurgical Research and Development Institute (CMRDI), P.O. Box 87, Helwan 11421, Cairo (Egypt); Rayan, D.A.; Turky, A.O. [Central Metallurgical Research and Development Institute (CMRDI), P.O. Box 87, Helwan 11421, Cairo (Egypt); Hessien, M.M. [Central Metallurgical Research and Development Institute (CMRDI), P.O. Box 87, Helwan 11421, Cairo (Egypt); Chemistry Department, Taif University (Saudi Arabia)

    2015-01-15

    Nanocrystalline Ni{sub 0.5}Zn{sub 0.5−x}Co{sub x}Fe{sub 2−z}Y{sub z}O{sub 4} powders (x=0–0.3 and z from 0 to 0.3) have been synthesized via a facile co-precipitation technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) are utilized in order to study the effect of variation of cobalt and yttrium substitutions and its impact on crystalline size, lattice parameter, X-ray density, microstructure and magnetic properties of the formed powders. X-ray diffraction data indicated that, after doping, all samples consisted of the main spinel phase for the formed precursors precipitated at pH 10 annealed at 1000 {sup o}C for 2 h. The lattice parameter and the unit cell were decreased linearly with increasing Co content whereas they were increased with increasing the Y incorporation. Additionally, the porosity was increased with increasing Co concentration while it was decreased with increasing the Y insertion. The mean ionic radii and hopping and bond lengths was decreased with the value of Co{sup 2+} and they were increased with the value of Y{sup 3+} ion as well as both of Y{sup 3+} and Co{sup 2+} ions. The microstructures of the produced powders were found to be cubic like structure. The addition of Y{sup 3+} ion suppressed the grain size whereas addition of Co{sup 2+} ion enhanced the grain growth availably. An examination of the magnetic properties revealed an increase in saturation magnetization with increasing Co and Y concentrations incorporation up to x=0.3. Meanwhile, the formed powders exhibited superparamagnetic characteristics. A high saturation magnetization (77.0 emu/g) was achieved for Ni{sub 0.5}Zn{sub 0.2}Co{sub 0.3}Fe{sub 2}O{sub 4} sample annealed at 1000 {sup o}C for 2 h. - Highlights: • Ni{sub 0.5}Zn{sub 0.5−x}Co{sub x}Fe{sub 2−z}Y{sub z}O{sub 4} powders were synthesized. • The porosity decreases with Y{sup 3+} and increases with Co{sup 2+}. • The bond lengths decrease with Co{sup 2

  16. Porous Hollow Superlattice NiMn2O4/NiCo2O4 Mesocrystals as a Highly Reversible Anode Material for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Lingjun Li

    2018-05-01

    Full Text Available As a promising high-capacity anode material for Li-ion batteries, NiMn2O4 always suffers from the poor intrinsic conductivity and the architectural collapse originating from the volume expansion during cycle. Herein, a combined structure and architecture modulation is proposed to tackle concurrently the two handicaps, via a facile and well-controlled solvothermal approach to synthesize NiMn2O4/NiCo2O4 mesocrystals with superlattice structure and hollow multi-porous architecture. It is demonstrated that the obtained NiCo1.5Mn0.5O4 sample is made up of a new mixed-phase NiMn2O4/NiCo2O4 compound system, with a high charge capacity of 532.2 mAh g−1 with 90.4% capacity retention after 100 cycles at a current density of 1 A g−1. The enhanced electrochemical performance can be attributed to the synergistic effects of the superlattice structure and the hollow multi-porous architecture of the NiMn2O4/NiCo2O4 compound. The superlattice structure can improve ionic conductivity to enhance charge transport kinetics of the bulk material, while the hollow multi-porous architecture can provide enough void spaces to alleviate the architectural change during cycling, and shorten the lithium ions diffusion and electron-transportation distances.

  17. Differential association of GABAB receptors with their effector ion channels in Purkinje cells.

    Science.gov (United States)

    Luján, Rafael; Aguado, Carolina; Ciruela, Francisco; Cózar, Javier; Kleindienst, David; de la Ossa, Luis; Bettler, Bernhard; Wickman, Kevin; Watanabe, Masahiko; Shigemoto, Ryuichi; Fukazawa, Yugo

    2018-04-01

    Metabotropic GABA B receptors mediate slow inhibitory effects presynaptically and postsynaptically through the modulation of different effector signalling pathways. Here, we analysed the distribution of GABA B receptors using highly sensitive SDS-digested freeze-fracture replica labelling in mouse cerebellar Purkinje cells. Immunoreactivity for GABA B1 was observed on presynaptic and, more abundantly, on postsynaptic compartments, showing both scattered and clustered distribution patterns. Quantitative analysis of immunoparticles revealed a somato-dendritic gradient, with the density of immunoparticles increasing 26-fold from somata to dendritic spines. To understand the spatial relationship of GABA B receptors with two key effector ion channels, the G protein-gated inwardly rectifying K + (GIRK/Kir3) channel and the voltage-dependent Ca 2+ channel, biochemical and immunohistochemical approaches were performed. Co-immunoprecipitation analysis demonstrated that GABA B receptors co-assembled with GIRK and Ca V 2.1 channels in the cerebellum. Using double-labelling immunoelectron microscopic techniques, co-clustering between GABA B1 and GIRK2 was detected in dendritic spines, whereas they were mainly segregated in the dendritic shafts. In contrast, co-clustering of GABA B1 and Ca V 2.1 was detected in dendritic shafts but not spines. Presynaptically, although no significant co-clustering of GABA B1 and GIRK2 or Ca V 2.1 channels was detected, inter-cluster distance for GABA B1 and GIRK2 was significantly smaller in the active zone than in the dendritic shafts, and that for GABA B1 and Ca V 2.1 was significantly smaller in the active zone than in the dendritic shafts and spines. Thus, GABA B receptors are associated with GIRK and Ca V 2.1 channels in different subcellular compartments. These data provide a better framework for understanding the different roles played by GABA B receptors and their effector ion channels in the cerebellar network.

  18. Neutron diffraction analysis and electrochemical performance of spinel Ni(Mn{sub 2−x}Co{sub x})O{sub 4} as anode materials for lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hu; Liu, Lei; Hu, Zhongbo [College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049 (China); Sun, Limei, E-mail: sunlm@ciae.ac.cn [Department of Nuclear and Physics, China Institute of Atomic Energy, Beijing 102413 (China); Han, Songbai; Liu, Yuntao; Chen, Dongfeng [Department of Nuclear and Physics, China Institute of Atomic Energy, Beijing 102413 (China); Liu, Xiangfeng, E-mail: liuxf@ucas.ac.cn [College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-05-15

    Highlights: • The reversible capacity and cyclability of Ni(Mn{sub 2−x}Co{sub x})O{sub 4} first increases and then decreases with increasing Co content. • Neutron diffraction and Rielveld refinements are applied to analyze the site occupancies of Mn, Co, O and Ni. • Excessive Co ions in 8a and 16d sites reduce the structure stability leading to poor electrochemical performance. - Abstract: The effects of Co substitution on the structure and electrochemical performances of spinel Ni(Mn{sub 2−x}Co{sub x})O{sub 4} (x = 0, 0.5, and 1.0) have been investigated. With the increase of Co content the lattice parameters decrease owing to the smaller ion radius of Co than Mn. The reversible capacity and cyclability of Ni(Mn{sub 2−x}Co{sub x})O{sub 4} first increase and then decrease with the increase of Co content and NiMn{sub 1.5}Co{sub 0.5}O{sub 4} shows the best electrochemical performance in compared to the other two samples. Neutron diffraction and Rielveld refinement are further applied to analyze the site occupancies of the elements of Mn, Co, O and Ni. A certain amount of Co ions substitution are favorable to enhance the electrochemical performance, but excessive Co ions in 8a and 16d sites reduce the stability of host structure which leads to the poor electrochemical performance.

  19. Ion clustering in aqueous salt solutions near the liquid/vapor interface

    Directory of Open Access Journals (Sweden)

    J.D. Smith

    2016-03-01

    Full Text Available Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions are used to study the effects of salts on the properties of the liquid/vapor interface. The simulations use the models which include both charge transfer and polarization effects. Pairing and the formation of larger ion clusters occurs both in the bulk and surface region, with a decreased tendency to form larger clusters near the interface. An analysis of the roughness of the surface reveals that the chloride salts, which have less tendency to be near the surface, have a roughness that is less than pure water, while the iodide salts, which have a greater surface affinity, have a larger roughness. This suggests that ions away from the surface and ions near the surface affect the interface in opposite ways.

  20. Oxidative Addition Reactions of I2 with [HIr4(CO10-n(PPh3 n(m-PPh2] (n = 1 and 2 and Crystal and Molecular Structure of [HIr4(m-I2(CO7 (PPh3(m-PPh2

    Directory of Open Access Journals (Sweden)

    Braga Dario

    2002-01-01

    Full Text Available The reactions of the cluster compounds [HIr4(CO10-n(PPh3 n(mu-PPh2] [n = 0, (1; 1, (2 and 2, (3] with I2 have been investigated. Compound 1 does not react, however, the presence of PPh3 in place of CO ligand(s activates the cluster. Both compounds 2 and 3 react with I2 under mild conditions to give [HIr4(mu-I2(CO7(PPh3(mu-PPh 2] (4, as the result of oxidative addition of I2 and dissociation of two CO ligands, or one CO and one PPh3 ligands, respectively. The molecular structure of 4, determined by an X-ray diffraction study, exhibits a butterfly arrangement of iridium atoms with the wings spanned by a mu-PPh2 ligand, the hinge bridged by a mu-H ligand, two hinge to wing tip edges bridged by iodine atoms and all metal atoms bearing two CO ligands, with the exception of one of the hinge atoms that contains a CO and a PPh3 ligands. This cluster exhibits the shortest average Irfraction three-quartersIr bond length [2.698(2 Å] observed so far for a derivative of 1 and this is in accord with the relatively high average oxidation state of its metal atoms (+1 for a carbonyl cluster compound.

  1. Investigations on carbon cluster formation in heavy ion irradiated polymers

    International Nuclear Information System (INIS)

    Tripathy, S.P.; Mishra, R.; Mawar, A.K.; Dwivedi, K.K.; Khathing, D.T.; Srivastava, A.; Avasthi, D.K.; Ghosh, S.; Fink, D.

    2000-01-01

    In polymers, the carbonaceous clusters are supposed to be responsible for the electrical conductivity. So, the irradiation of organic polymers namely polypropylene (8μ) and polyimide (50μ) by energetic heavy ions 28 Si and 58 Ni produce significant changes in the size of these clusters leading to the corresponding change in the band gap and other electrical properties as revealed by the UV-VIS spectroscopic examinations. (author)

  2. Mg-controlled formation of Mg–Ag co-clusters in initial aged Al–Cu–Mg–Ag alloys

    International Nuclear Information System (INIS)

    Bai, Song; Liu, Zhiyi; Zhou, Xuanwei; Xia, Peng; Zeng, Sumin

    2014-01-01

    Highlights: • The strongest age-hardening response was found in 0.81Mg alloy. • Quantitative APT study showed strong dependence of Mg–Ag co-clustering on Mg content. • A critical Mg content related to the greatest Mg–Ag co-clustering was revealed. • The evolution from Mg–Ag co-clusters to Ω phase was accelerated in 1.18Mg alloy. - Abstract: The effect of Mg variations on the number density, solute concentrations and sizes of Mg–Ag co-clusters at the early aging stage, as well as the age-hardening response of different Al–Cu–Mg–Ag alloys, was well investigated by a combination of Vickers hardness measurement, transmission electron microscopy (TEM) and atom probe tomography (APT). The strongest age-hardening response at 165 °C was found in 0.81Mg alloy, accompanied by the highest nucleation rate of Mg–Ag co-clusters after aging for 0.5 h. However, the least response was revealed in 0.39Mg alloy. By quantitative APT analysis, the observed trend in the total number density of Mg–Ag co-clusters suggested the following order: 0.81Mg alloy > 0.39Mg alloy > 1.18Mg alloy. This parabolic change in the total number density of Mg–Ag co-clusters with increasing Mg highlighted the existence of a critical Mg content, which contributed to the greatest nucleation kinetics of Mg–Ag co-clusters. As Mg increased from 0.39 to 0.81, the formation of small Mg–Ag co-clusters was significantly promoted, whereas the number density of large Mg–Ag co-clusters almost remained constant. Moreover, the remarkable enrichment of Cu within Mg–Ag co-clusters indicated that the accelerated evolution from Mg–Ag co-clusters to Ω phase was responsible for the lowest number density of Mg–Ag co-clusters in 1.18Mg alloy after aging at 165 °C for 0.5 h

  3. Ion-molecule interactions in crossed-beams. [N/sup +/-H/sub 2/; F/sup +/-H; CO/sub 2//sup +/-D/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S.G.

    1980-09-01

    Interactions of the ions N/sup +/, F/sup +/, and CO/sub 2//sup +/ with H/sub 2/ and/or its isotopes were examined using the crossed-beam technique in the low (< 4 eV) initial relative energy. For the reaction N/sup +/(/sup 3/P) + H/sub 2/ ..-->.. NH/sup +/ + H, complex formation dominates up to 1.9 eV and a substantial interaction occurs between all collision partners up to 3.6 eV. The distribution of N/sup +/ scattered nonreactively from H/sub 2/ also showed a long-lived complex channel below 1.9 eV. The reaction F/sup +/(/sup 3/P) + H/sub 2/ ..-->..FH/sup +/ + H proceeded by a direct reaction mechanism at 0.20 to 1.07 eV. The reaction CO/sub 2//sup +/ + D/sub 2/ ..-->.. DCO/sub 2//sup +/ + D gives asymmetric product distributions at 0.27 eV and above, indicating a direct reaction mechanism. Results indicated that there are probably barriers in the exit channels for DCO/sub 2//sup +/, DCO/sup +/, and D/sub 2/O/sup +/ products. The electronic state distributions of the N/sup +/, F/sup +/, and CO/sub 2//sup +/ beams was investigated using beam attenuation and total luminescence techniques.

  4. Single-, double-, and triple-photoionization cross sections of carbon monoxide (CO) and ionic fragmentation of CO+, CO2+, and CO3+

    International Nuclear Information System (INIS)

    Masuoka, T.; Nakamura, E.

    1993-01-01

    Single-, double-, and triple-photoionization processes of carbon monoxide (CO) have been studied in the photon-energy region of 37--100 eV by use of time-of-flight mass spectrometry and a photoion-photoion-coincidence method together with synchrotron radiation. The single-, double-, and triple-photoionization cross sections of CO are determined. Ion branching ratios and the partial cross sections for the individual ions respectively produced from the precursors CO + and CO 2+ are determined separately at excitation energies where the molecular and dissociative single- and double-photoionization processes compete. The threshold for the molecular double photoionization was found to be 41.3±0.2 eV. Furthermore, in single photoionization, the production of CO + is dominant whereas with double photoionization dissociation becomes dominant

  5. Structural characterization of layered Na0.5Co0.5Mn0.5O2 material as a promising cathode for sodium-ion batteries

    Science.gov (United States)

    Manikandan, Palanisamy; Heo, Seongwoo; Kim, Hyun Woo; Jeong, Hu Young; Lee, Eungje; Kim, Youngsik

    2017-09-01

    Layered Na0.5Co0.5Mn0.5O2 material is synthesized through a facile mixed hydroxy-carbonate route using (Co0.5Mn0.5)2(OH)2CO3 precursor and well characterized as a hexagonal layered structure under P63/mmc space group. The lattice parameters and unit cell volume (a = 2.8363 Å, c = 11.3152 Å and V = 78.83 Å3) are calculated by Rietveld refinement analysis. A flaky-bundle morphology is obtained to the layered Na0.5Co0.5Mn0.5O2 material with the hexagonal flake size ∼30 nm. Advanced transmission electron microscopic images are revealed the local structure of the layered Na0.5Co0.5Mn0.5O2 material with contrasting bright dots and faint dark dots corresponding to the Co/Mn and Na atoms. Two oxidation and reduction peaks are occurred in a cyclic voltammetric analysis corresponding to Co3+/Co4+ and Mn3+/Mn4+ redox processes. These reversible processes are attributed to the intercalation/de-intercalation of Na+ ions into the host structure of layered Na0.5Co0.5Mn0.5O2 material. Accordingly, the sodium cell is delivered the initial charge-discharge capacity 53/144 mAh g-1 at 0.5 C, which cycling studies are extended to rate capability test at 1 C, 3 C and 5C. Eventually, the Na-ion full-cell is yielded cathode charge-discharge capacity 55/52 mAh g-1 at 0.212 mA and exhibited as a high voltage cathode for Na-ion batteries.

  6. The reflection of hierarchical cluster analysis of co-occurrence matrices in SPSS

    NARCIS (Netherlands)

    Zhou, Q.; Leng, F.; Leydesdorff, L.

    2015-01-01

    Purpose: To discuss the problems arising from hierarchical cluster analysis of co-occurrence matrices in SPSS, and the corresponding solutions. Design/methodology/approach: We design different methods of using the SPSS hierarchical clustering module for co-occurrence matrices in order to compare

  7. Crystal structure and electronic states of Co and Gd ions in a Gd0.4Sr0.6CoO2.85 single crystal

    Science.gov (United States)

    Platunov, M. S.; Dudnikov, V. A.; Orlov, Yu. S.; Kazak, N. V.; Solovyov, L. A.; Zubavichus, Ya. V.; Veligzhanin, A. A.; Dorovatovskii, P. V.; Vereshchagin, S. N.; Shaykhutdinov, K. A.; Ovchinnikov, S. G.

    2016-02-01

    X-ray diffraction and X-ray absorption near edge structure (XANES) spectra have been measured at the Co K-edge and Gd L 3-edge in GdCoO3 and Gd0.4Sr0.6CoO2.85 cobaltites. The effect of Sr substitution on the crystal structure and electronic and magnetic states of Co3+ ions in a Gd0.4Sr0.6CoO2.85 single crystal has been analyzed. The XANES measurements at the Co K-edge have not showed a noticeable shift of the absorption edge with an increase in the concentration of Sr. This indicates that the effective valence of cobalt does not change. An increase in the intensity of absorption at the Gd L 3-edge is due to an increase in the degree of hybridization of the Gd(5 d) and O(2 p) states. The effect of hole doping on the magnetic properties results in the appearance of the ferromagnetic component and in a significant increase in the magnetic moment.

  8. Modelling of Krn+ Clusters. II. Photoabsorption Spectra of Small Clusters (n=2 - 5)

    Czech Academy of Sciences Publication Activity Database

    Kalus, R.; Paidarová, Ivana; Hrivňák, D.; Gadea, F. X.

    2004-01-01

    Roč. 298, 1/3 (2004), s. 155-166 ISSN 0301-0104 R&D Projects: GA ČR GA203/02/1204 Grant - others:Barrande Program(XE) 2003-024-1 Institutional research plan: CEZ:AV0Z4040901 Keywords : krypton * rare gases * cluster ions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.316, year: 2004

  9. Anion-Exchange Membrane Fuel Cells with Improved CO2 Tolerance: Impact of Chemically Induced Bicarbonate Ion Consumption.

    Science.gov (United States)

    Katayama, Yu; Yamauchi, Kosuke; Hayashi, Kohei; Okanishi, Takeou; Muroyama, Hiroki; Matsui, Toshiaki; Kikkawa, Yuuki; Negishi, Takayuki; Watanabe, Shin; Isomura, Takenori; Eguchi, Koichi

    2017-08-30

    Over the last few decades, because of the significant development of anion exchange membranes, increasing efforts have been devoted the realization of anion exchange membrane fuel cells (AEMFCs) that operate with the supply of hydrogen generated on-site. In this paper, ammonia was selected as a hydrogen source, following which the effect of conceivable impurities, unreacted NH 3 and atmospheric CO 2 , on the performance of AEMFCs was established. As expected, we show that these impurities worsen the performance of AEMFCs significantly. Furthermore, with the help of in situ attenuated total reflection infrared (ATR-IR) spectroscopy, it was revealed that the degradation of the cell performance was primarily due to the inhibition of the hydrogen oxidation reaction (HOR). This is attributed to the active site occupation by CO-related adspecies derived from (bi)carbonate adspecies. Interestingly, this degradation in the HOR activity is suppressed in the presence of both NH 3 and HCO 3 - because of the bicarbonate ion consumption reaction induced by the existence of NH 3 . Further analysis using in situ ATR-IR and electrochemical methods revealed that the poisonous CO-related adspecies were completely removed under NH 3 -HCO 3 - conditions, accompanied by the improvement in HOR activity. Finally, a fuel cell test was conducted by using the practical AEMFC with the supply of NH 3 -contained H 2 gas to the anode and ambient air to the cathode. The result confirmed the validity of this positive effect of NH 3 -HCO 3 - coexistence on CO 2 -tolerence of AEMFCs. The cell performance achieved nearly 95% of that without any impurity in the fuels. These results clearly show the impact of the chemically induced bicarbonate ion consumption reaction on the realization of highly CO 2 -tolerent AEMFCs.

  10. Surface Collisions of Small Cluster Ions at Incident Energies 10-102 eV

    Czech Academy of Sciences Publication Activity Database

    Herman, Zdeněk

    2004-01-01

    Roč. 233, - (2004), s. 361-371 ISSN 1387-3806 R&D Projects: GA MŠk ME 561 Grant - others:XE(CZ) EURATOM-IPP.CR Institutional research plan: CEZ:AV0Z4040901 Keywords : surface collisions * cluster ions * unimolecular dissociation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.235, year: 2004

  11. Study of radicals, clusters and transition state species by anion photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Don Wesley [Univ. of California, Berkeley, CA (United States)

    1994-08-01

    Free radicals, elemental and van der Waals clusters and transition state species for bimolecular chemical reactions are investigated using anion photoelectron spectroscopy. Several low-lying electronic states of ozone have been identified via photoelectron spectroscopy of O3-. A characterization of these states is important to models for atmospheric ozone reaction kinetics. The fluoroformyloxyl radical, FCO2, has been investigated, providing vibrational frequencies and energies for two electronic states. The technique has also been employed to make the first direct observation and characterization of the NNO2 molecule. Several electronic states are observed for this species which is believed to play a role as a reactive intermediate in the N + NO2 reaction. The experimental results for all three of these radicals are supplemented by ab initio investigations of their molecular properties. The clusters investigations include studies of elemental carbon clusters (C2- - C11-), and van der Waals clusters (X-(CO2)n, X = I, Br, Cl; n {le} 13 and I- (N2O)n=1--11). Primarily linear clusters are observed for the smaller carbon clusters, while the spectra of the larger clusters contain contribution from cyclic anion photodetachment. Very interesting ion-solvent interactions are observed in the X-(CO2)n clusters. The transition state regions for several bimolecular chemical reactions have also been investigated by photodetachment of a negative ion precursor possessing a geometry similar to that of the transition state species. These spectra show features which are assigned to motions of the unstable neutral complex existing between reactants and products.

  12. Carbon monoxide activation via O-bound CO using decamethylscandocinium-hydridoborate ion pairs.

    Science.gov (United States)

    Berkefeld, Andreas; Piers, Warren E; Parvez, Masood; Castro, Ludovic; Maron, Laurent; Eisenstein, Odile

    2012-07-04

    Ion pairs [Cp*(2)Sc](+)[HB(p-C(6)F(4)R)(3)](-) (R = F, 1-F; R = H, 1-H) were prepared and shown to be unreactive toward D(2) and α-olefins, leading to the conclusion that no back-transfer of hydride from boron to scandium occurs. Nevertheless, reaction with CO is observed to yield two products, both ion pairs of the [Cp*(2)Sc](+) cation with formylborate (2-R) and borataepoxide (3-R) counteranions. DFT calculations show that these products arise from the carbonyl adduct of the [Cp*(2)Sc](+) in which the CO is bonded to scandium through the oxygen atom, not the carbon atom. The formylborate 2-R is formed in a two-step process initiated by an abstraction of the hydride by the carbon end of an O-bound CO, which forms an η(2)-formyl intermediate that adds, in a second step, the borane at the carbon. The borataepoxide 3-R is suggested to result from an isomerization of 2-R. This unprecedented reaction represents a new way to activate CO via a reaction channel emanating from the ephemeral isocarbonyl isomer of the CO adduct.

  13. Infrared spectroscopy of ionic clusters

    International Nuclear Information System (INIS)

    Price, J.M.

    1990-11-01

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm -1 region. The species studied include: the hydrated hydronium ions, H 3 O + (H 2 O) 3 -10 , ammoniated ammonium ions, NH 4 + (NH 3 ) 1 -10 and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH 4 + (NH 3 ) n (H 2 O) m (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs

  14. Molecular growth in clusters of polycyclic aromatic hydrocarbons induced by collisions with ions

    International Nuclear Information System (INIS)

    Delaunay, Rudy

    2016-01-01

    This thesis concerns the experimental study of the interaction between low energy ions (keV range) and neutral isolated molecules or clusters of polycyclic aromatic hydrocarbons (PAH) in the gas phase. The use of ionising radiations on these complex molecular systems of astrophysical interest allowed to highlight processes of statistical fragmentation, corresponding to the redistribution of the energy through the degrees of freedom of the target, and non-statistical fragmentation, linked to binary collisions of the ions on the nuclei of the target. A mechanism of intermolecular growth in clusters of PAH is observed. It is associated to the ultrafast (≤ ps) formation of fragments inside the clusters following binary collisions. The presence of a molecular environment around the fragments formed during the interaction may initiate a process of reactivity between the fragments and the molecules of the clusters. More precisely, the study focusses on the importance of the electronic stopping power SE and the nuclear stopping power SN of the projectile ion. It shows that the molecular growth is enhanced when SN is higher than SE. This can be explained by the fact that the deposit of energy is mainly due to the interaction with the nuclei of the target. The process of growth has been observed for all the molecules of PAH studied during this thesis and also for nitrogenated analogues of the molecule of anthracene. This demonstrates that molecular growth may be efficiently induced by collisions of low energy ions with clusters of PAH. (author) [fr

  15. Active sites of ligand-protected Au25 nanoparticle catalysts for CO2 electroreduction to CO

    Science.gov (United States)

    Alfonso, Dominic R.; Kauffman, Douglas; Matranga, Christopher

    2016-05-01

    Recent experimental studies have reported the electrochemical reduction of carbon dioxide (CO2) into CO at atomically precise negatively charged Au25- nanoclusters. The studies showed CO2 conversion at remarkably low overpotentials, but the exact mechanisms and nature of the active sites remain unclear. We used first-principles density functional theory and continuum solvation models to examine the role of the cluster during electrochemical CO2 reduction and analyze the free energies of proposed intermediate species. Contrary to previous assumptions, our results show that the fully ligand protected cluster is not an active CO2 reduction catalyst because formation of the crucial carboxyl intermediate required very high electrochemical potentials. Instead, our calculations suggest that the reduction process likely occurs on a dethiolated gold site, and adsorbed carboxyl intermediate formation was significantly stabilized at dethiolated gold sites. These findings point to the crucial role of exposed metal sites during electrochemical CO2 reduction at gold nanocluster catalysts.

  16. Interaction of nanosecond laser pulse with tetramethyl silane (Si(CH34 clusters: Generation of multiply charged silicon and carbon ions

    Directory of Open Access Journals (Sweden)

    Purav M. Badani

    2011-12-01

    Full Text Available Present work reports significantly high levels of ionization, eventually leading to Coulomb explosion of Tetramethyl silane (TMS clusters, on interaction with laser pulses of intensity ∼109 W/cm2. Tetramethyl silane clusters, prepared by supersonic expansion were photoionized at 266, 355 or 532 nm and the resultant ions were detected using time-of-flight mass spectrometer. It is observed that wavelength of irradiation and the size of the cluster are crucial parameters which drastically affect the nature of charge species generated upon photoionization of cluster. The results show that clusters absorb significantly higher energy from the laser field at longer wavelengths (532 nm and generate multiply charged silicon and carbon ions which have large kinetic energies. Further, laser-cluster interaction at different wavelengths has been quantified and charge densities at 266, 355 and 532 nm are found to be 4x 1010, 5x 1010 and 5x 1011 charges/cm3 respectively. These unusual results have been rationalized based on dominance of secondary ionization processes at 532 nm ultimately leading to Coulomb explosion of clusters. In another set of experiments, multiply charged ions of Ar (up to +5 state and Kr (up to +6 state were observed when TMS doped inert gas clusters were photoionized at 532 and 355 nm. The extent of energy absorption at these two wavelengths is clearly manifested from the charge state of the atomic ions generated upon Coulomb disintegration of the doped cluster. These experiments thus demonstrate a novel method for generation of multiply charged atomic ions of inert gases at laser intensity of ∼ 109 W/cm2. The average size of the cluster exhibiting Coulomb explosion phenomena under giga watt intensity conditions has been estimated to be ∼ 6 nm. Experimental results obtained in the present work agree qualitatively with the model proposed earlier [D. Niu, H. Li, F. Liang, L. Wen, X. Luo, B. Wang, and H. Qu, J. Chem. Phys. 122, 151103

  17. Particle modeling of transport of α-ray generated ion clusters in air

    International Nuclear Information System (INIS)

    Tong, Lizhu; Nanbu, Kenichi; Hirata, Yosuke; Izumi, Mikio; Miyamoto, Yasuaki; Yamaguchi, Hiromi

    2006-01-01

    A particle model is developed using the test-particle Monte Carlo method to study the transport properties of α-ray generated ion clusters in a flow of air. An efficient ion-molecule collision model is proposed to simulate the collisions between ion and air molecule. The simulations are performed for a steady state of ion transport in a circular pipe. In the steady state, generation of ions is balanced with such losses of ions as absorption of the measuring sensor or pipe wall and disappearance by positive-negative ion recombination. The calculated ion current to the measuring sensor agrees well with the previous measured data. (author)

  18. The observation of the Ne-like ion resonance line satellites for CrXV ... Ni XIX CO2-laser produced plasma

    International Nuclear Information System (INIS)

    Khakhalin, S.Ya.; Faenov, A.Ya.; Skobelev, I.Yu.; Pikuz, S.A.; Nilsen, J.; Osterheld, A.

    1994-01-01

    We present an analysis of dielectronic satellite spectra of Ne-like ion resonance lines for elements from Cr to Ni. For these low-Z elements, we use spectra from strongly underionized CO 2 -laser produced plasma to minimize the emission from open L-shell ions. This simplifies the spectra and allows the identification of satellite lines caused by radiative transitions from autoionizing states of sodium like ions. Good agreement between the satellite structure calculations and the experimental emission spectra is obtained. (orig.)

  19. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Energy Technology Data Exchange (ETDEWEB)

    Rupprechter, G.; Kaichev, V.V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V.I

    2004-07-31

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H{sub 2} mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH{sub x}O species as precursors for C---O bond cleavage and that the formation of CH{sub x}O is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  20. Preparation and electrochemical properties of mesoporous NiCo2O4 double-hemisphere used as anode for lithium-ion battery.

    Science.gov (United States)

    Yang, Yue; Huang, Guo Yong; Sun, Hongyu; Ahmad, Mashkoor; Mou, Qinyao; Zhang, Hongmei

    2018-06-19

    NiCo 2 O 4 is a potential anode material for lithium ion battery due to its many advantages, such as high theoretical capacitance, low cost, and good electrochemical activity. In this study, mesoporous NiCo 2 O 4 double-hemisphere (3-5 μm) with high surface area (270.68 m 2 ·g -1 ) and excellent electrochemical performances has been synthesized through a facile precipitation method followed with thermal treatment process. The prepared NiCo 2 O 4 is pure phase and can be indexed as a face-centered-cubic with a typical spinel structure. Electrochemical tests show the prepared material has high specific capacities (910 mAh·g -1 at 100 mA·g -1 ), excellent cyclicity (908  mAh·g -1 at 100 mA·g -1 after 60 cycles) and remarkable high rate performance (after 100 cycles, 585 mAh·g -1 at 400 mAh·g -1 , 415 mAh·g -1 at 800 mAh·g -1 and 320 mAh·g -1 at 1600 mAh·g -1 with coulombic efficiencies of almost 100%). The excellent performances of prepared NiCo 2 O 4 are mainly caused by the unique double-hemisphere structure, which has large surface area, gives material more opportunity to contact with electrolyte and facilitates lithium ion spreading into the material along the radical direction, resulting in a promising application for next-generation lithium-ion batteries. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Synergistic effects of iodine and silver ions co-implanted in 6H-SiC

    Science.gov (United States)

    Kuhudzai, R. J.; Malherbe, J. B.; Hlatshwayo, T. T.; van der Berg, N. G.; Devaraj, A.; Zhu, Z.; Nandasiri, M.

    2015-12-01

    Motivated by the aim of understanding the release of fission products through the SiC coating of fuel kernels in modern high temperature nuclear reactors, a fundamental investigation is conducted to understand the synergistic effects of implanted silver (Ag) and iodine (I) in 6H-SiC. The implantation of the individual species, as well as the co-implantation of 360 keV ions of I and Ag at room temperature in 6H-SiC and their subsequent annealing behaviour has been investigated by Secondary Ion Mass Spectrometry (SIMS), Atom Probe Tomography (APT) and X-ray Photoelectron Spectroscopy (XPS). SIMS and APT measurements indicated the presence of Ag in the co-implanted samples after annealing at 1500 °C for 30 h in sharp contrast to the samples implanted with Ag only. In samples implanted with Ag only, complete loss of the implanted Ag was observed. However, for I only implanted samples, some iodine was retained. APT of annealed co-implanted 6H-SiC showed clear spatial association of Ag and I clusters in SiC, which can be attributed to the observed I assisted retention of Ag after annealing. Such detailed studies will be necessary to identify the fundamental mechanism of fission products migration through SiC coatings.

  2. Bitwise dimensional co-clustering for analytical workloads

    NARCIS (Netherlands)

    Baumann, Stephan; Boncz, Peter; Sattler, Kai Uwe

    2016-01-01

    Analytical workloads in data warehouses often include heavy joins where queries involve multiple fact tables in addition to the typical star-patterns, dimensional grouping and selections. In this paper we propose a new processing and storage framework called bitwise dimensional co-clustering (BDCC)

  3. Chromosomal aberrations induced by 12C6+ ions and 6Co γ-rays in mouse immature oocytes

    International Nuclear Information System (INIS)

    Zhang Hong; Duan Xin; Yuan Zhigang; Li Wenjian; Zhou Guangming; Zhou Qingming; Bing Liu; Min Fengling; Li Xiaoda; Xie Yi

    2006-01-01

    The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of 12 C 6+ ion or 6 Co γ-ray. Chromosomal aberrations were analyzed in metaphase II oocytes at 7 weeks after irradiation. The relative biological effectiveness (RBE) of 12 C 6+ ion was calculated with respect to 6 Co γ-ray for the induction of chromosomal aberrations. The 12 C 6+ ion and 6 Co γ-ray dose-response relationships for chromosomal aberrations were plotted by linear quadratic models. The data showed that there was a dose-related increase in frequency of chromosomal aberrations in all the treated groups compared to controls. The RBE values for 12 C 6+ ions relative to 6 Co γ-rays were 2.49, 2.29, 1.57, 1.42 or 1.32 for the doses of 0.5, 1.0, 2.0, 4.0 or 6.0 Gy, respectively. Moreover, a different distribution of the various types of aberrations has been found for 12 C 6+ ion and 6 Co γ-ray irradiations. The dose-response relationships for 12 C 6+ ion and 6 Co γ-ray exhibited positive correlations. The results from the present study may be helpful for assessing genetic damage following exposure of immature oocytes to ionizing radiation

  4. The model for solubility of CO2 in saline groundwater with complex ions and the application on Erdos basin

    International Nuclear Information System (INIS)

    Wang Lu; Yu Qingchun

    2014-01-01

    To obtain accurate solubility of CO 2 is one of problems that need solutions urgently in CO 2 sequestration within saline groundwater. However, there are few data published for solubility of CO 2 under geological sequestration conditions. In order to fill the gap of the experimental study, the solubility of CO 2 in five formations of Erdos Basin was explored in this research. Groundwater samples in five reservoirs were carried out through an observation well in the Erdos Basin. The chemical composition was determined and experiments measuring CO 2 solubility were carried out in the synthetic water samples. Krichevsky-Kasarnovsky equation was established to analyze the experimental data. The relationship between concentration of K + , Na + , Ca 2+ , Mg 2+ and the solubility of CO 2 was analyzed and an excellent liner fit was found, which quantifies the impact of ions on the solubility of cO 2 . Solubility data were compared to the model prediction over the temperature and pressure ranges of 318 ∼ 348 K and 8 ∼ 11 MPa. The average absolute deviation is 2.11%. The results can be used as a parameter for the evaluation of the CO 2 storage capacity in deep saline aquifer of Erdos Basin. (authors)

  5. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Science.gov (United States)

    Rupprechter, G.; Kaichev, V. V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V. I.

    2004-07-01

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H 2 mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH xO species as precursors for CO bond cleavage and that the formation of CH xO is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  6. Analysis of ligand-protein exchange by Clustering of Ligand Diffusion Coefficient Pairs (CoLD-CoP)

    Science.gov (United States)

    Snyder, David A.; Chantova, Mihaela; Chaudhry, Saadia

    2015-06-01

    NMR spectroscopy is a powerful tool in describing protein structures and protein activity for pharmaceutical and biochemical development. This study describes a method to determine weak binding ligands in biological systems by using hierarchic diffusion coefficient clustering of multidimensional data obtained with a 400 MHz Bruker NMR. Comparison of DOSY spectrums of ligands of the chemical library in the presence and absence of target proteins show translational diffusion rates for small molecules upon interaction with macromolecules. For weak binders such as compounds found in fragment libraries, changes in diffusion rates upon macromolecular binding are on the order of the precision of DOSY diffusion measurements, and identifying such subtle shifts in diffusion requires careful statistical analysis. The "CoLD-CoP" (Clustering of Ligand Diffusion Coefficient Pairs) method presented here uses SAHN clustering to identify protein-binders in a chemical library or even a not fully characterized metabolite mixture. We will show how DOSY NMR and the "CoLD-CoP" method complement each other in identifying the most suitable candidates for lysozyme and wheat germ acid phosphatase.

  7. Polyatomic ions in inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Ferguson, Jill Wisnewski; Dudley, Timothy J.; Sears, Kyle C.; McIntyre, Sally M.; Gordon, Mark S.; Houk, R.S.

    2009-01-01

    Several polyatomic ions in inductively coupled plasma-mass spectrometry are studied experimentally and by computational methods. Novel calculations based on spin-restricted open shell second order perturbation theory (ZAPT2) and coupled cluster (CCSD(T)) theory are performed to determine the energies, structures and partition functions of the ions. These values are combined with experimental data to evaluate a dissociation constant and gas kinetic temperature (T gas ) value. In our opinion, the resulting T gas value can sometimes be interpreted to deduce the location where the polyatomic ion of interest is generated. The dissociation of N 2 H + to N 2 + leads to a calculated T gas of 4550 to 4900 K, depending on the computational data used. The COH + to CO + system yields a similar temperature, which is not surprising considering the similar energies and structures of COH + and N 2 H + . The dissociation of H 2 CO + to HCO + leads to a much lower T gas ( 2 COH + to HCOH + generates a T gas value between those from the other H x CO + ions studied here. All of these measured T gas values correspond to formation of extra polyatomic ion in the interface or extraction region. The computations reveal the existence of isomers such as HCO + and COH + , and H 2 CO + and HCOH + , which have virtually the same m/z values and need to be considered in the interpretation of results.

  8. Cluster observations of the high-latitude magnetopause and cusp: initial results from the CIS ion instruments

    Directory of Open Access Journals (Sweden)

    J. M. Bosqued

    2001-09-01

    Full Text Available Launched on an elliptical high inclination orbit (apogee: 19.6 RE since January 2001 the Cluster satellites have been conducting the first detailed three-dimensional studies of the high-latitude dayside magnetosphere, including the exterior cusp, neighbouring boundary layers and magnetopause regions. Cluster satellites carry the CIS ion spectrometers that provide high-precision, 3D distributions of low-energy (<35 keV/e ions every 4 s. This paper presents the first two observations of the cusp and/or magnetopause behaviour made under different interplanetary magnetic field (IMF conditions. Flow directions, 3D distribution functions, density profiles and ion composition profiles are analyzed to demonstrate the high variability of high-latitude regions. In the first crossing analyzed (26 January 2001, dusk side, IMF-BZ < 0, multiple, isolated boundary layer, magnetopause and magnetosheath encounters clearly occurred on a quasi-steady basis for ~ 2 hours. CIS ion instruments show systematic accelerated flows in the current layer and adjacent boundary layers on the Earthward side of the magnetopause. Multi-point analysis of the magnetopause, combining magnetic and plasma data from the four Cluster spacecraft, demonstrates that oscillatory outward-inward motions occur with a normal speed of the order of ± 40 km/s; the thickness of the high-latitude current layer is evaluated to be of the order of 900–1000 km. Alfvénic accelerated flows and D-shaped distributions are convincing signatures of a magnetic reconnection occurring equatorward of the Cluster satellites. Moreover, the internal magnetic and plasma structure of a flux transfer event (FTE is analyzed in detail; its size along the magnetopause surface is ~ 12 000 km and it convects with a velocity of ~ 200 km/s. The second event analyzed (2 February 2001 corresponds to the first Cluster pass within the cusp when the IMF-BZ component was northward directed. The analysis of relevant CIS plasma

  9. Exploring the atmospheric chemistry of O2SO3- and assessing the maximum turnover number of ion-catalysed H2SO4 formation

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Kurtén, T.; Vehkamäki, H.

    2013-01-01

    molecule, but reaction (b) is in general much more probable. Although we are unable to assess the overall importance of this cycle in the real atmosphere due to the unknown influence of CO2 and NOx, we roughly estimate that ion-induced catalysis may contribute with several percent of H2SO4 levels......It has recently been demonstrated that the O2SO3- ion forms in the atmosphere as a natural consequence of ionizing radiation. Here, we present a density functional theory-based study of the reactions of O2SO3- with O-3. The most important reactions are (a) oxidation to O3SO3- and (b) cluster...... the two major sinks for O2SO3- is assessed, thereby providing a measure of the maximum turnover number of ion-catalysed SO2 oxidation, i.e. how many SO2 can be oxidized per free electron. The rate ratio between reactions (a) and (b) is significantly altered by the presence or absence of a single water...

  10. Solubility of NaNd(CO3)2.6H2O(c) in concentrated Na2CO3 and NaHCO3 solutions

    International Nuclear Information System (INIS)

    Rao, L.; Rai, D.; Felmy, A.R.; Fulton, R.W.; Novak, C.F.

    1996-01-01

    NaNd(CO 3 ) 2 x 6 H 2 O(c) was identified to be the final equilibrium solid phase in suspensions containing concentrated sodium carbonate (0.1 to 2.0 M) and sodium bicarbonate (0.1 to 1.0 M), with either NaNd(CO 3 ) 2 x 6 H 2 O(c) or Nd 2 (CO 3 ) 3 x xH 2 O(s) as initial solids. A thermodynamic model, based on Pitzer's specific into-interaction approach, was developed to interpret the solubility of NaNd(CO 3 ) 2 x 6 H 2 O(c) as functions of sodium carbonate and sodium bicarbonate concentrations. In this model, the solubility data of NaNd(CO 3 ) 2 x 6 H 2 O(c) were explained by assuming the formation of NdCO 3 + , Nd(CO 3 ) 2 - and Nd(CO 3 ) 3 3- species and invoking the specific ion interactions between Na + and Nd(CO 3 ) 3 3- . Ion interaction parameters for Na + -Nd(CO 3 ) 3 3- were developed to fit the solubility data. Based on the model calculations, Nd(CO 3 ) 3 3- was the predominant aqueous neodymium species in 0.1 to 2 M sodium carbonate and 0.1 to 1 M sodium bicarbonate solutions. The logarithm of the NaNd(CO 3 ) 2 x 6 H 2 O solubility product (NaNd(CO 3 ) 2 x 6 H 2 O(c)=Na + +Nd 3+ +2 CO 3 2- +6 H 2 O) was calculated to be -21.39. This model also provided satisfactory interpretation of the solubility data of the analogous Am(III) system in less concentrated carbonate and bicarbonate solutions. (orig.)

  11. Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Jiangang; Annis, James; /Fermilab

    2010-10-01

    Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. Google Earth (in sky mode) provides a highly interactive environment for visualizing the sky. By encoding the galaxy cluster information into a kml/kmz file, one can use Google Earth as a tool for examining galaxy clusters and fly across them freely. However, the resolution of the images provided by Google Earth is not very high. This is partially because the major imagery google earth used is from Sloan Digital Sky Survey (SDSS) (SDSS collaboration 2000) and the resolutions have been reduced to speed up the web transferring. To have higher resolution images, you need to add your own images in a way that Google Earth can understand. The SDSS co-added data are the co-addition of {approx}100 scans of images from SDSS stripe 82 (Annis et al. 2010). It provides the deepest images based on SDSS and reach as deep as about redshift 1.0. Based on the co-added images, we created color images in a way as described by Lupton et al. (2004) and convert the color images to Google Earth compatible images using wcs2kml (Brewer et al. 2007). The images are stored at a public server at Fermi National Accelerator Laboratory and can be accessed by the public. To view those images in Google Earth, you need to download a kmz file, which contains the links to the color images, and then open the kmz file with your Google Earth. To meet different needs for resolutions, we provide three kmz files corresponding to low, medium and high resolution images. We recommend the high resolution one as long as you have a broadband Internet connection, though you should choose to download any of them, depending on your own needs and Internet speed. After you open the downloaded kmz file with Google Earth (in sky mode), it takes about 5 minutes (depending on your Internet connection and the resolution of images you

  12. Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

    International Nuclear Information System (INIS)

    Hao, Jiangang; Annis, James

    2010-01-01

    Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. Google Earth (in sky mode) provides a highly interactive environment for visualizing the sky. By encoding the galaxy cluster information into a kml/kmz file, one can use Google Earth as a tool for examining galaxy clusters and fly across them freely. However, the resolution of the images provided by Google Earth is not very high. This is partially because the major imagery google earth used is from Sloan Digital Sky Survey (SDSS) (SDSS collaboration 2000) and the resolutions have been reduced to speed up the web transferring. To have higher resolution images, you need to add your own images in a way that Google Earth can understand. The SDSS co-added data are the co-addition of ∼100 scans of images from SDSS stripe 82 (Annis et al. 2010). It provides the deepest images based on SDSS and reach as deep as about redshift 1.0. Based on the co-added images, we created color images in a way as described by Lupton et al. (2004) and convert the color images to Google Earth compatible images using wcs2kml (Brewer et al. 2007). The images are stored at a public server at Fermi National Accelerator Laboratory and can be accessed by the public. To view those images in Google Earth, you need to download a kmz file, which contains the links to the color images, and then open the kmz file with your Google Earth. To meet different needs for resolutions, we provide three kmz files corresponding to low, medium and high resolution images. We recommend the high resolution one as long as you have a broadband Internet connection, though you should choose to download any of them, depending on your own needs and Internet speed. After you open the downloaded kmz file with Google Earth (in sky mode), it takes about 5 minutes (depending on your Internet connection and the resolution of images you want

  13. Formation and characterization of nanoparticles formed by sequential ion implantation of Au and Co into SiO2

    International Nuclear Information System (INIS)

    Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S.G.; Foran, G.J.; Ridgway, M.C.

    2007-01-01

    Nanoparticles (NPs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . After Au implantation and annealing, Co implantations were carried out at room temperature (RT) and 400 deg. C, respectively, with no subsequent annealing. The NPs were investigated by means of Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and extended X-ray absorption fine structure spectroscopy (EXAFS). TEM shows the formation of Co-Au core-shell NPs for the Co implantation at 400 deg. C. EXAFS measurements indicate significant strain in the NPs and a bond-length expansion of the Co-Co bonds in the NP core with a concomitant contraction of the Au-Au bonds in the Au shells. NPs are also observed by TEM for the Co implantation performed at RT, however, a lack of crystallinity is apparent from electron diffraction and EXAFS measurements

  14. Ion emission in solids bombarded with Aun+ (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range

    International Nuclear Information System (INIS)

    Wehbe, Nimer

    2006-06-01

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry

  15. Synthesis of hollandite-type Li yMn 1- xCo xO 2 (x = 0-0.15) by Li + ion-exchange in molten salt and the electrochemical property for rechargeable lithium battery electrodes

    Science.gov (United States)

    Kumagai, Naoaki; Oshitari, Satoru; Komaba, Shinichi; Kadoma, Yoshihiro

    The Li + ion-exchange reaction of K +-type α-K 0.14MnO 1.93·0.18H 2O and its Co-doped α-K 0.14(Mn 0.85Co 0.15)O 1.96·0.21H 2O with a large (2 × 2) tunnel structure has been investigated in a LiNO 3/LiCl molten salt at 300 °C. The Li + ion-exchanged products were examined by chemical analysis, X-ray diffraction, and scanning and transmission electron microscopic measurements. Almost all the K + ions and the hydrogens of water molecules in the (2 × 2) tunnel of α-MnO 2 and its Co-doped one were exchanged by Li + ions in the molten salt, resulting in Li +-type α-MnO 2 and its Co-doped one containing Li + ions as well as Li 2O (lithium oxide) in the (2 × 2) tunnel with maintaining the original hollandite structure. The electrochemical properties including charge-discharge cycling of the Li + ion-exchanged α-MnO 2 and its Co-doped samples have been investigated as insertion compounds in the search for new cathode materials for rechargeable lithium batteries. The Li + ion-exchanged α-MnO 2 and its Co-doped samples provided higher capacities than the K +-type parent materials on initial discharge and charge-discharge cyclings, probably due to the structural stabilization with the existence of Li 2O in the (2 × 2) tunnels.

  16. Implantation of energetic D{sup +} ions into carbon dioxide ices and implications for our solar system: formation of D{sub 2}O and D{sub 2}CO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Chris J.; Ennis, Courtney P.; Kaiser, Ralf I., E-mail: ralfk@hawaii.edu [Department of Chemistry, University of Hawai' i at Mānoa, Honolulu, HI 96822 (United States)

    2014-10-10

    Carbon dioxide (CO{sub 2}) ices were irradiated with energetic D{sup +} ions to simulate the exposure of oxygen-bearing solar system ices to energetic protons from the solar wind and magnetospheric sources. The formation of species was observed online and in situ by exploiting FTIR spectroscopy. Molecular products include ozone (O{sub 3}), carbon oxides (CO{sub 3}(C {sub 2v}, D {sub 3h}), CO{sub 4}, CO{sub 5}, CO{sub 6}), D2-water (D{sub 2}O), and D2-carbonic acid (D{sub 2}CO{sub 3}). Species released into the gas phase were sampled via a quadrupole mass spectrometer, and possible minor contributions from D2-formaldehyde (D{sub 2}CO), D4-methanol (CD{sub 3}OD), and D2-formic acid (DCOOD) were additionally identified. The feasibility of several reaction networks was investigated by determining their ability to fit the observed temporal column densities of 10 key species that were quantified during the irradiation period. Directly relevant to the CO{sub 2}-bearing ices of comets, icy satellites in the outer solar system, and the ice caps on Mars, this work illustrates for the first time that D2-water is formed as a product of the exposure of CO{sub 2} ices to D{sup +} ions. These findings provide strong support for water formation from oxygen-bearing materials via non-thermal hydrogen atoms, and predict reaction pathways that are likely to be unfolding on the surfaces of asteroids and the Moon.

  17. Infrared spectroscopy of ionic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Price, J.M. (California Univ., Berkeley, CA (USA). Dept. of Chemistry Lawrence Berkeley Lab., CA (USA))

    1990-11-01

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm{sup {minus}1} region. The species studied include: the hydrated hydronium ions, H{sub 3}O{sup +} (H{sub 2}O){sub 3 {minus}10}, ammoniated ammonium ions, NH{sub 4}{sup +}(NH{sub 3}){sub 1 {minus}10} and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH{sub 4}{sup +}(NH{sub 3}){sub n}(H{sub 2}O){sub m} (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs.

  18. Studies on bare and Mg-doped LiCoO2 as a cathode material for lithium ion batteries

    CSIR Research Space (South Africa)

    Reddy, MV

    2014-05-01

    Full Text Available at ScienceDirect Electrochimica Acta jo ur nal ho me p age: www.elsev ier .com/ locate /e lec tac ta Graphical Abstract Electrochimica Acta xxx (2013) xxx–xxx Studies on Bare and Mg-doped LiCoO2 as a cathode material for Lithium ion Batteries M.V. Reddy... for Lithium ion Batteries M.V. Reddy∗, Thor Wei Jie, Charl J. Jafta, Kenneth I. Ozoemena, Mkhulu K. Mathe, A. Sree Kumaran Nair, Soo Soon Peng, M. Sobri Idris, Geetha Balakrishna, Fabian I. Ezema, B.V.R. Chowdari • Layered compounds, Li...

  19. Effect of low-oxygen-concentration layer on iron gettering capability of carbon-cluster ion-implanted Si wafer for CMOS image sensors

    Science.gov (United States)

    Onaka-Masada, Ayumi; Nakai, Toshiro; Okuyama, Ryosuke; Okuda, Hidehiko; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Kurita, Kazunari; Sueoka, Koji

    2018-02-01

    The effect of oxygen (O) concentration on the Fe gettering capability in a carbon-cluster (C3H5) ion-implanted region was investigated by comparing a Czochralski (CZ)-grown silicon substrate and an epitaxial growth layer. A high Fe gettering efficiency in a carbon-cluster ion-implanted epitaxial growth layer, which has a low oxygen region, was observed by deep-level transient spectroscopy (DLTS) and secondary ion mass spectroscopy (SIMS). It was demonstrated that the amount of gettered Fe in the epitaxial growth layer is approximately two times higher than that in the CZ-grown silicon substrate. Furthermore, by measuring the cathodeluminescence, the number of intrinsic point defects induced by carbon-cluster ion implantation was found to differ between the CZ-grown silicon substrate and the epitaxial growth layer. It is suggested that Fe gettering by carbon-cluster ion implantation comes through point defect clusters, and that O in the carbon-cluster ion-implanted region affects the formation of gettering sinks for Fe.

  20. The observation of the Ne-like ion resonance line satellites for CrXV. Ni XIX CO[sub 2]-laser produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khakhalin, S.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Faenov, A.Ya. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Skobelev, I.Yu. (MISDC, NPO ' ' VNIIFTRI' ' , Mendeleevo (Russian Federation)); Pikuz, S.A. (P. N. Lebedev Physical Inst., Russian Academy of Science, Moscow (Russian Federation)); Nilsen, J. (Lawrence Livermore National Lab., Livermore, CA (United States)); Osterheld, A. (Lawrence Livermore National Lab., Livermore, CA (United States))

    1994-08-01

    We present an analysis of dielectronic satellite spectra of Ne-like ion resonance lines for elements from Cr to Ni. For these low-Z elements, we use spectra from strongly underionized CO[sub 2]-laser produced plasma to minimize the emission from open L-shell ions. This simplifies the spectra and allows the identification of satellite lines caused by radiative transitions from autoionizing states of sodium like ions. Good agreement between the satellite structure calculations and the experimental emission spectra is obtained. (orig.).

  1. Synthesis and characterization of Cr doped CoFe2O4

    Science.gov (United States)

    Verma, Kavita; Patel, K. R.; Ram, Sahi; Barbar, S. K.

    2016-05-01

    Polycrystalline samples of pure and Cr-doped cobalt ferrite (CoFe2O4 and CoCrFeO4) were prepared by solid state reaction route method. X-ray diffraction pattern infers that both the samples are in single phase with Fd3m space group. Slight reduction in the lattice parameter of CoCrFeO4 has been observed as compared to CoFe2O4. The dielectric dispersion has been explained on the basis of Fe2+ ↔ Fe3+ hopping mechanism. The polarizations at lower frequencies are mainly attributed to electronic exchange between Fe2+ ↔ Fe3+ ions on the octahedral site in the ferrite lattice. In the present system a part from n-type charge carrier (Fe3+/Fe2+), the presence of (Co3+/Co2+) ions give rise to p-type charge carrier. Therefore in addition to n-type charge carrier, the local displacement of p-type charge carrier in direction of external electric field also contributes to net polarization. However, the dielectric constant and loss tangent of CoCrFeO4 are found to be lower than CoFe2O4 and is attributed to the availability of ferrous ion. CoCrFeO4 have less amount of ferrous ion available for polarization as compared to that of CoFe2O4. The impedance spectra reveal a grain interior contribution to the conduction process.

  2. Ni–Fe–S Cubanes in CO2 Reduction Electrocatalysis

    DEFF Research Database (Denmark)

    Varley, J. B.; Hansen, H. A.; Ammitzbøll, Nadia Luciw

    2013-01-01

    In this work, we perform extensive mechanistic studies of CO2 (electro)reduction by analogs to the active sites of carbon monoxide dehydrogenase (CODH) enzymes. We explore structure–property relationships for different cluster compositions and interpret the results with a model for CO2...... electroreduction we recently developed and applied to transition metal catalysts. Our results validate the effectiveness of the CODH in catalyzing this important reaction and give insight into why specific cluster compositions were adopted by nature....

  3. Colorimetric detection and removal of radioactive Co ions using sodium alginate-based composite beads

    International Nuclear Information System (INIS)

    Kim, Daigeun; Jo, Ara; Yang, Hee-Man; Seo, Bum-Kyoung; Lee, Kune-Woo; Lee, Taek Seung

    2017-01-01

    Highlights: • Organic/inorganic hybridized alginate beads were newly synthesized via sol-gel chemistry. • Interaction between the azopyridine and metal ion is the main cause of Co ion detection. • The beads showed improved stability and least leakage of azopyridine during use. • Removal of Co ion was assessed by the ion-exchange of carboxylate groups in alginate. • The beads with dual functions of detection and removal of Co ion were successfully accomplished. - Abstract: We demonstrate a simple method for the visual determination and removal of Co ions using a bead-shaped, capturing probe based on hybridized sodium alginate. For Co ions, the designed protocol consisted of three main constituents: an azopyridine-based Co ion-probe for visual detection; sodium alginate as an adsorbent for the Co ion and a bead construct for removal and structure; silica as a linker for the probe and the alginate, leading to a robust structure. When the composite beads were exposed to Co ions, the yellow color of the beads turned to intensive violet and the color intensity was associated with the Co ion concentration. The color variation was quantified using red-green-blue (RGB) color values that were obtained with a scanner and evaluated with Photoshop. The technique achieved both visual recognition with obvious color change of the beads and efficient removal of the radioactive 60 Co ion. The sensing and removal of any radioactive isotope could be achieved with an appropriate sensing probe, to provide a simple and universal platform for remediation.

  4. Colorimetric detection and removal of radioactive Co ions using sodium alginate-based composite beads

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daigeun; Jo, Ara [Organic and Optoelectronic Materials Laboratory, Department of Organic Materials Engineering, Chungnam National University, Daejeon 34134 (Korea, Republic of); Yang, Hee-Man; Seo, Bum-Kyoung; Lee, Kune-Woo [Decontamination and Decommissioning Research Division, Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Lee, Taek Seung, E-mail: tslee@cnu.ac.kr [Organic and Optoelectronic Materials Laboratory, Department of Organic Materials Engineering, Chungnam National University, Daejeon 34134 (Korea, Republic of)

    2017-03-15

    Highlights: • Organic/inorganic hybridized alginate beads were newly synthesized via sol-gel chemistry. • Interaction between the azopyridine and metal ion is the main cause of Co ion detection. • The beads showed improved stability and least leakage of azopyridine during use. • Removal of Co ion was assessed by the ion-exchange of carboxylate groups in alginate. • The beads with dual functions of detection and removal of Co ion were successfully accomplished. - Abstract: We demonstrate a simple method for the visual determination and removal of Co ions using a bead-shaped, capturing probe based on hybridized sodium alginate. For Co ions, the designed protocol consisted of three main constituents: an azopyridine-based Co ion-probe for visual detection; sodium alginate as an adsorbent for the Co ion and a bead construct for removal and structure; silica as a linker for the probe and the alginate, leading to a robust structure. When the composite beads were exposed to Co ions, the yellow color of the beads turned to intensive violet and the color intensity was associated with the Co ion concentration. The color variation was quantified using red-green-blue (RGB) color values that were obtained with a scanner and evaluated with Photoshop. The technique achieved both visual recognition with obvious color change of the beads and efficient removal of the radioactive {sup 60}Co ion. The sensing and removal of any radioactive isotope could be achieved with an appropriate sensing probe, to provide a simple and universal platform for remediation.

  5. Generation of H{sub 2} and CO by solar thermochemical splitting of H{sub 2}O and CO{sub 2} by employing metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Rao, C.N.R., E-mail: cnrrao@jncasr.ac.in; Dey, Sunita

    2016-10-15

    Generation of H{sub 2} and CO by splitting H{sub 2}O and CO{sub 2} respectively constitutes an important aspect of the present-day concerns with energy and environment. The solar thermochemical route making use of metal oxides is a viable means of accomplishing these reduction reactions. The method essentially involves reducing a metal oxide by heating and passing H{sub 2}O or CO{sub 2} over the nonstoichiometric oxide to cause reverse oxidation by abstracting oxygen from H{sub 2}O or CO{sub 2}. While ceria, perovskites and other oxides have been investigated for this purpose, recent studies have demonstrated the superior performance of perovskites of the type Ln{sub 1−x}A{sub x}Mn{sub 1−y}M{sub y}O{sub 3} (Ln=rare earth, A=alkaline earth, M=various +2 and +3 metal ions), in the thermochemical generation of H{sub 2} and CO. We present the important results obtained hitherto to point out how the alkaine earth and the Ln ions, specially the radius of the latter, determine the performance of the perovskites. The encouraging results obtained are exemplefied by Y{sub 0.5}Sr{sub 0.5}MnO{sub 3} which releases 483 µmol/g of O{sub 2} at 1673 K and produces 757 µmol/g of CO from CO{sub 2} at 1173 K. The production of H{sub 2} from H{sub 2}O is also quite appreciable. Modification of the B site ion of the perovskite also affects the performance. In addition to perovskites, we present the generation of H{sub 2} based on the Mn{sub 3}O{sub 4}/NaMnO{sub 2} cycle briefly. - Graphical abstract: Ln{sub 0.5}A{sub 0.5}Mn{sub 1−x}M{sub x}O{sub 3} (Ln=lanthanide; A=Ca, Sr; M=Al, Ga, Sc, Mg, Cr, Fe, Co) perovskites are employed for the two step thermochemical splitting of CO{sub 2} and H{sub 2}O for the generation of CO and H{sub 2}. - Highlights: • Perovskite oxides based on Mn are ideal for the two-step thermochemical splitting of CO{sub 2} and H{sub 2}O. • In Ln{sub 1−x}A{sub x}MnO{sub 3} perovskite (Ln=rare earth, A=alkaline earth) both Ln and A ions play major roles

  6. Si clusters/defective graphene composites as Li-ion batteries anode materials: A density functional study

    International Nuclear Information System (INIS)

    Li, Meng; Liu, Yue-Jie; Zhao, Jing-xiang; Wang, Xiao-guang

    2015-01-01

    Highlights: • We study the interaction between Si clusters with pristine and defective graphene. • We find that the binding strength of Si clusters on graphene can be enhanced to different degrees after introducing various defects. • It is found that both graphene and Si cluster in the Si/graphene composites can preserve their Li uptake ability. - Abstract: Recently, the Si/graphene hybrid composites have attracted considerable attention due to their potential application for Li-ion batteries. How to effectively anchor Si clusters to graphene substrates to ensure their stability is an important factor to determine their performance for Li-ion batteries. In the present work, we have performed comprehensive density functional theory (DFT) calculations to investigate the geometric structures, stability, and electronic properties of the deposited Si clusters on defective graphenes as well as their potential applications for Li-ion batteries. The results indicate that the interfacial bonding between these Si clusters with the pristine graphene is quietly weak with a small adsorption energy (<−0.21 eV). Due to the presence of vacancy site, the binding strength of Si clusters on defective graphene is much stronger than that of pristine one, accompanying with a certain amount of charge transfer from Si clusters to graphene substrates. Moreover, the ability of Si/graphene hybrids for Li uptake is studied by calculating the adsorption of Li atoms. We find that both graphenes and Si clusters in the Si/graphene composites preserve their Li uptake ability, indicating that graphenes not only server as buffer materials for accommodating the expansion of Si cluster, but also provide additional intercalation sites for Li

  7. Electrochemical reaction mechanisms under various charge-discharge operating conditions for Li1.2Ni0.13Mn0.54Co0.13O2 in a lithium-ion battery

    Science.gov (United States)

    Konishi, Hiroaki; Hirano, Tatsumi; Takamatsu, Daiko; Gunji, Akira; Feng, Xiaoliang; Furutsuki, Sho; Okumura, Takefumi; Terada, Shohei; Tamura, Kazuhisa

    2018-06-01

    The potential in each state of charge (SOC) during charging of Li1.2Ni0.13Mn0.54Co0.13O2 is higher than that during discharging. In other words, the potential hysteresis occurs between charging and discharging. Furthermore, the potential in each SOC changes according to the charge-discharge operating conditions, indicating that the charge-discharge reaction mechanism is also affected. To clarify the effect of charge-discharge operating conditions on the electrochemical reaction, Li1.2Ni0.13Mn0.54Co0.13O2 was charged and discharged under various charge-discharge operating ranges, and open-circuit potential (OCP), crystal structure, and oxidation states of the transition metals were evaluated by electrochemical measurement, X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS). These results indicate that OCP, lattice parameters, and oxidation states of the transition metals of Li1.2Ni0.13Mn0.54Co0.13O2 in each SOC are not constant. The XRD results indicate that two phases, namely, LiNi0.33Mn0.33Co0.33O2-like and Li2MnO3-like, exist in Li1.2Ni0.13Mn0.54Co0.13O2. For the LiNi0.33Mn0.33Co0.33O2-like phase, the relationship between OCP, lattice parameters, and oxidation states of the transition metals in each SOC is not affected by the charge-discharge operating conditions, indicating that extraction and insertion of lithium ions for the LiNi0.33Mn0.33Co0.33O2-like phase progresses at almost the same potential. Although the extraction and insertion of lithium ions for the Li2MnO3-like phase progresses at almost the same potential in the low-SOC region, the OCP and lattice parameter in each SOC in the high-SOC region are not constant. Therefore, the extraction of lithium ions from the Li2MnO3-like phase in the high-SOC region causes the potential hysteresis of Li1.2Ni0.13Mn0.54Co0.13O2.

  8. High speed pulsed laser cutting of LiCoO2 Li-ion battery electrodes

    Science.gov (United States)

    Lutey, Adrian H. A.; Fortunato, Alessandro; Carmignato, Simone; Fiorini, Maurizio

    2017-09-01

    Laser cutting of Li-ion battery electrodes represents an alternative to mechanical blanking that avoids complications associated with tool wear and allows assembly of different cell geometries with a single device. In this study, laser cutting of LiCoO2 Li-ion battery electrodes is performed at up to 5m /s with a 1064nm wavelength nanosecond pulsed fiber laser with a maximum average power of 500W and a repetition rate of up to 2MHz . Minimum average cutting power for cathode and anode multi-layer films is established for 12 parameter groups with velocities over the range 1 - 5m /s , varying laser pulse fluence and overlap. Within the tested parameter range, minimum energy per unit cut length is found to decrease with increasing repetition rate and velocity. SEM analysis of the resulting cut edges reveals visible clearance widths in the range 20 - 50 μm , with cut quality found to improve with velocity due to a reduction in lateral heat conduction losses. Raman line map spectra reveal changes in the cathode at 60 μm from the cut edge, where bands at 486cm-1 and 595cm-1 , corresponding to the Eg and A1g modes of LiCoO2 , are replaced with a single wide band centered at 544cm-1 , and evidence of carbon black is no longer present. No changes in Raman spectra are observed in the anode. The obtained results suggest that further improvements in cutting efficiency and quality could be achieved by increasing the repetition rate above 2MHz , thereby improving ablation efficiency of the metallic conductor layers. The laser source utilized in the present study nonetheless represents an immediately available solution for repeatability and throughput that are superior to mechanical blanking.

  9. The Existence of a Designer Al=Al Double Bond in the LiAl2 H4- Cluster Formed by Electronic Transmutation.

    Science.gov (United States)

    Lundell, Katie A; Zhang, Xinxing; Boldyrev, Alexander I; Bowen, Kit H

    2017-12-22

    The Al=Al double bond is elusive in chemistry. Herein we report the results obtained via combined photoelectron spectroscopy and ab initio studies of the LiAl 2 H 4 - cluster that confirm the formation of a conventional Al=Al double bond. Comprehensive searches for the most stable structures of the LiAl 2 H 4 - cluster have shown that the global minimum isomer I possesses a geometric structure which resembles that of Si 2 H 4 , demonstrating a successful example of the transmutation of Al atoms into Si atoms by electron donation. Theoretical simulations of the photoelectron spectrum discovered the coexistence of two isomers in the ion beam, including the one with the Al=Al double bond. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Evidence for nanoscale two-dimensional Co clusters in CoPt{sub 3} films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Cross, J O [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Newville, M [Consortium for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637 (United States); Maranville, B B; Hellman, F [Department of Physics, University of California at San Diego, La Jolla, CA 92093 (United States); Bordel, C [Department of Physics, University of California at Berkeley, CA 94720 (United States); Harris, V G, E-mail: cbordel@berkeley.ed [Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States)

    2010-04-14

    The length scale of the local chemical anisotropy responsible for the growth-temperature-induced perpendicular magnetic anisotropy of face-centered cubic CoPt{sub 3} alloy films was investigated using polarized extended x-ray absorption fine structure (EXAFS). These x-ray measurements were performed on a series of four (111) CoPt{sub 3} films epitaxially grown on (0001) sapphire substrates. The EXAFS data show a preference for Co-Co pairs parallel to the film plane when the film exhibits magnetic anisotropy, and random chemical order otherwise. Furthermore, atomic pair correlation anisotropy was evidenced only in the EXAFS signal from the next neighbors to the absorbing Co atoms and from multiple scattering paths focused through the next neighbors. This suggests that the Co clusters are no more than a few atoms in extent in the plane and one monolayer in extent out of the plane. Our EXAFS results confirm the correlation between perpendicular magnetic anisotropy and two-dimensional Co segregation in CoPt{sub 3} alloy films, and establish a length scale on the order of 10 A for the Co clusters.

  11. Vacancy defect and defect cluster energetics in ion-implanted ZnO

    Science.gov (United States)

    Dong, Yufeng; Tuomisto, F.; Svensson, B. G.; Kuznetsov, A. Yu.; Brillson, Leonard J.

    2010-02-01

    We have used depth-resolved cathodoluminescence, positron annihilation, and surface photovoltage spectroscopies to determine the energy levels of Zn vacancies and vacancy clusters in bulk ZnO crystals. Doppler broadening-measured transformation of Zn vacancies to vacancy clusters with annealing shifts defect energies significantly lower in the ZnO band gap. Zn and corresponding O vacancy-related depth distributions provide a consistent explanation of depth-dependent resistivity and carrier-concentration changes induced by ion implantation.

  12. Influence of the manganese and cobalt content on the electrochemical performance of P2-Na0.67MnxCo1-xO2 cathodes for sodium-ion batteries.

    Science.gov (United States)

    Hemalatha, K; Jayakumar, M; Prakash, A S

    2018-01-23

    The resurgence of sodium-ion batteries in recent years is due to their potential ability to form intercalation compounds possessing a high specific capacity and energy density comparable to existing lithium systems. To comprehend the role of cobalt substitution in the structure and electrochemical performance of Na 0.67 MnO 2 , the solid solutions of P2-Na 0.67 Mn x Co 1-x O 2 (x = 0.25, 0.5, 0.75) are synthesized and characterized. The XRD-Rietveld analysis revealed that the Co-substitution in Na 0.67 MnO 2 decreases lattice parameters 'a' and 'c' resulting in the contraction of MO 6 octahedra and the enlargement of inter-layer 'd' spacing. XPS indicates that the isovalent cobalt substitution in Na 0.67 MnO 2 results in the partial/complete replacement of Jahn-Teller active trivalent manganese to form low-spin complexes of better structural stability. The Na-ion diffusion coefficient, D Na + , derived from cyclic voltammetry and impedance spectroscopy, confirmed the enhanced mass transport in Co-rich phases compared to Mn-rich phases. Furthermore, higher diffusion coefficient values are observed for Co 3+ /Co 4+ than for their Mn 3+ /Mn 4+ redox processes. In addition, Co-rich phases exhibit a high structural stability and superior capacity retention, whereas Mn-rich phases discharge higher capacities.

  13. Pore-scale imaging of capillary trapped supercritical CO2 as controlled by water-wet vs. CO2-wet media and grain shapes

    Science.gov (United States)

    Chaudhary, K.; Cardenas, M.; Wolfe, W. W.; Maisano, J. A.; Ketcham, R. A.; Bennett, P.

    2013-12-01

    The capillary trapping of supercritical CO2 (s-CO2) is postulated to comprise up to 90% of permanently trapped CO2 injected during geologic sequestration. Successive s-CO2/brine flooding experiments under reservoir conditions showed that water-wet rounded beads trapped 15% of injected s-CO2 both as clusters and as individual ganglia, whereas CO2¬-wet beads trapped only 2% of the injected s-CO2 as minute pockets in pore constrictions. Angular water-wet grains trapped 20% of the CO2 but flow was affected by preferential flow. Thus, capillary trapping is a viable mechanism for the permanent CO2 storage, but its success is constrained by the media wettability.

  14. CO Oxidation on the Au15Cu15 Cluster and the Role of Vacancies in the MgO(100) Support

    DEFF Research Database (Denmark)

    Ma, Li; Melander, Marko; Weckman, Timo

    2016-01-01

    analysis reveals that CO oxidation is very sensitive to the CO partial pressure, as the relatively strong CO binding leads readily to CO poisoning of the cluster surface sites and hinders CO2 formation. For low CO partial pressures, the catalytic reaction takes place already at 150 K for the cluster...

  15. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  16. Magnetism, structure and chemical order in small CoPd clusters: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Mokkath, Junais Habeeb, E-mail: Junais.Mokkath@kaust.edu.sa

    2014-01-15

    The structural, electronic and magnetic properties of small Co{sub m}Pd{sub n}(N=m+n=8,m=0−N) nanoalloy clusters are studied in the framework of a generalized-gradient approximation to density-functional theory. The optimized cluster structures have a clear tendency to maximize the number of nearest-neighbor CoCo pairs. The magnetic order is found to be ferromagnetic-like (FM) for all the ground-state structures. Antiferromagnetic-like spin arrangements were found in some low-lying isomers. The average magnetic moment per atom μ{sup ¯}{sub N} increases approximately linearly with Co content. A remarkable enhancement of the local Co moments is observed as a result of Pd doping. This is a consequence of the increase in the number of Co d holes, due to CoPd charge transfer, combined with the reduced local coordination. The influence of spin–orbit interactions on the cluster properties is also discussed. - Highlights: • This work analyses the structural and magnetic properties of CoPd nanoclusters. • The magnetic order is found to be ferromagnetic-like for all the ground-state structures. • The average magnetic moment per atom increases approximately linearly with Co content. • The influence of spin–orbit interactions on the cluster properties is discussed.

  17. Microwave-Assisted Synthesis of NiCo2O4 Double-Shelled Hollow Spheres for High-Performance Sodium Ion Batteries

    Science.gov (United States)

    Zhang, Xiong; Zhou, Yanping; Luo, Bin; Zhu, Huacheng; Chu, Wei; Huang, Kama

    2018-03-01

    The ternary transitional metal oxide NiCo2O4 is a promising anode material for sodium ion batteries due to its high theoretical capacity and superior electrical conductivity. However, its sodium storage capability is severely limited by the sluggish sodiation/desodiation reaction kinetics. Herein, NiCo2O4 double-shelled hollow spheres were synthesized via a microwave-assisted, fast solvothermal synthetic procedure in a mixture of isopropanol and glycerol, followed by annealing. Isopropanol played a vital role in the precipitation of nickel and cobalt, and the shrinkage of the glycerol quasi-emulsion under heat treatment was responsible for the formation of the double-shelled nanostructure. The as-synthesized product was tested as an anode material in a sodium ion battery, was found to exhibit a high reversible specific capacity of 511 mAh g-1 at 100 mA g-1, and deliver high capacity retention after 100 cycles. [Figure not available: see fulltext.

  18. CO Oxidation by Subnanometer AgxAu3–x Supported Clusters via Density Functional Theory Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Negreiros, Fabio R.; Sementa, Luca; Barcaro, Giovanni; Vajda, S.; Apra, Edoardo; Fortunelli, Alessandro

    2012-09-07

    The activity of AgxAu3–x/MgO(100) clusters in CO oxidation is investigated computationally via systematic sampling techniques. It is found that these subnanometer species transform after ligand adsorption into reaction complexes which catalyze CO oxidation through a variety of different mechanisms, occurring via both Langmuir–Hinshelwood and Eley–Rideal paths and in some cases directly involving the oxide support. The alloyed Ag2Au1 cluster is proposed as the best catalyst in terms of efficiency and robustness.

  19. Determination of interstellar pickup ion distributions in the solar wind with SOHO and Cluster

    Directory of Open Access Journals (Sweden)

    E. Möbius

    1996-05-01

    Full Text Available Over the last 10 years, the experimental basis for the study of the local interstellar medium has been substantially enhanced by the direct detection of interstellar pickup ions and of interstellar neutral helium within the heliosphere. Pickup ions can be studied for a wide range of interstellar species. However, currently the accuracy of the method to determine the parameters of the interstellar medium, namely neutral density, temperature and relative velocity, is hampered by two problems: (1 In most cases the crucial ionization rates are not available from simultaneous measurements and (2 the transport of the pickup ions in the interplanetary medium substantially modifies the measured spatial distribution of the ions. In this study we will discuss how the enhanced capabilities of the instrumentation on SOHO and Cluster in combination with ongoing efforts to model the pickup ion distributions will lead to a significant improvement over the coming years.

  20. ALICE HLT Cluster operation during ALICE Run 2

    Science.gov (United States)

    Lehrbach, J.; Krzewicki, M.; Rohr, D.; Engel, H.; Gomez Ramirez, A.; Lindenstruth, V.; Berzano, D.; ALICE Collaboration

    2017-10-01

    ALICE (A Large Ion Collider Experiment) is one of the four major detectors located at the LHC at CERN, focusing on the study of heavy-ion collisions. The ALICE High Level Trigger (HLT) is a compute cluster which reconstructs the events and compresses the data in real-time. The data compression by the HLT is a vital part of data taking especially during the heavy-ion runs in order to be able to store the data which implies that reliability of the whole cluster is an important matter. To guarantee a consistent state among all compute nodes of the HLT cluster we have automatized the operation as much as possible. For automatic deployment of the nodes we use Foreman with locally mirrored repositories and for configuration management of the nodes we use Puppet. Important parameters like temperatures, network traffic, CPU load etc. of the nodes are monitored with Zabbix. During periods without beam the HLT cluster is used for tests and as one of the WLCG Grid sites to compute offline jobs in order to maximize the usage of our cluster. To prevent interference with normal HLT operations we separate the virtual machines running the Grid jobs from the normal HLT operation via virtual networks (VLANs). In this paper we give an overview of the ALICE HLT operation in 2016.

  1. THE SLOAN DIGITAL SKY SURVEY CO-ADD: CROSS-CORRELATION WEAK LENSING AND TOMOGRAPHY OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Simet, Melanie; Dodelson, Scott; Kubo, Jeffrey M.; Annis, James T.; Hao Jiangang; Johnston, David; Lin, Huan; Soares-Santos, Marcelle; Reis, Ribamar R. R.; Seo, Hee-Jong

    2012-01-01

    The shapes of distant galaxies are sheared by intervening galaxy clusters. We examine this effect in Stripe 82, a 275 deg 2 region observed multiple times in the Sloan Digital Sky Survey (SDSS) and co-added to achieve greater depth. We obtain a mass-richness calibration that is similar to other SDSS analyses, demonstrating that the co-addition process did not adversely affect the lensing signal. We also propose a new parameterization of the effect of tomography on the cluster lensing signal which does not require binning in redshift, and we show that using this parameterization we can detect tomography for stacked clusters at varying redshifts. Finally, due to the sensitivity of the tomographic detection to accurately marginalize over the effect of the cluster mass, we show that tomography at low redshift (where dependence on exact cosmological models is weak) can be used to constrain mass profiles in clusters.

  2. Study of small carbon and semiconductor clusters using negative ion threshold photodetachment spectroscopy

    International Nuclear Information System (INIS)

    Arnold, C.C.

    1994-08-01

    The bonding and electronics of several small carbon and semiconductor clusters containing less than ten atoms are probed using negative ion threshold photodetachment (zero electron kinetic energy, or ZEKE) spectroscopy. ZEKE spectroscopy is a particularly advantageous technique for small cluster study, as it combines mass selection with good spectroscopic resolution. The ground and low-lying electronic states of small clusters in general can be accessed by detaching an electron from the ground anion state. The clusters studied using this technique and described in this work are C 6 - /C 6 , Si n - /Si n (n = 2, 3, 4), Ge 2 - /Ge 2 , In 2 P - /In 2 P,InP 2 - /InP 2 , and Ga 2 As - . The total photodetachment cross sections of several other small carbon clusters and the ZEKE spectrum of the I - ·CH 3 I S N 2 reaction complex are also presented to illustrate the versatility of the experimental apparatus. Clusters with so few atoms do not exhibit bulk properties. However, each specie exhibits bonding properties that relate to the type of bonding found in the bulk. C 6 , as has been predicted, exhibits a linear cumulenic structure, where double bonds connect all six carbon atoms. This double bonding reflects how important π bonding is in certain phases of pure carbon (graphite and fullerenes). The symmetric stretch frequencies observed in the C 6 - spectra, however, are in poor agreement with the calculated values. Also observed as sharp structure in total photodetachment cross section scans was an excited anion state bound by only ∼40 cm -1 relative to the detachment continuum. This excited anion state appears to be a valence bound state, possible because of the high electron affinity of C 6 , and the open shell of the anion

  3. Layered oxides-LiNi1/3Co1/3Mn1/3O2 as anode electrode for symmetric rechargeable lithium-ion batteries

    Science.gov (United States)

    Wang, Yuesheng; Feng, Zimin; Yang, Shi-Ze; Gagnon, Catherine; Gariépy, Vincent; Laul, Dharminder; Zhu, Wen; Veillette, René; Trudeau, Michel L.; Guerfi, Abdelbast; Zaghib, Karim

    2018-02-01

    High-performance and long-cycling rechargeable lithium-ion batteries have been in steadily increasing demand for the past decades. Nevertheless, the two dominant anodes at the moment, graphite and L4T5O12, suffer from a safety issue of lithium plating (operating voltage at ∼ 0.1 V vs. Li+/Li) and low capacity (175 mAh/g), respectively. Here, we report LiNi1/3Co1/3Mn1/3O2 as an alternative anode material which has a working voltage of ∼1.1 V and a capacity as high as 330 mAh/g at the current rate of C/15. Symmetric cells with both electrodes containing LiNi1/3Co1/3Mn1/3O2 can deliver average discharge voltage of 2.2 V. In-situ XRD, HRTEM and first principles calculations indicate that the reaction mechanism of a LiNi1/3Co1/3Mn1/3O2 anode is comprised mainly of conversion. Both the fundamental understanding and practical demonstrations suggest that LiNi1/3Co1/3Mn1/3O2 is a promising negative electrode material for lithium-ion batteries.

  4. Non-parametric co-clustering of large scale sparse bipartite networks on the GPU

    DEFF Research Database (Denmark)

    Hansen, Toke Jansen; Mørup, Morten; Hansen, Lars Kai

    2011-01-01

    of row and column clusters from a hypothesis space of an infinite number of clusters. To reach large scale applications of co-clustering we exploit that parameter inference for co-clustering is well suited for parallel computing. We develop a generic GPU framework for efficient inference on large scale...... sparse bipartite networks and achieve a speedup of two orders of magnitude compared to estimation based on conventional CPUs. In terms of scalability we find for networks with more than 100 million links that reliable inference can be achieved in less than an hour on a single GPU. To efficiently manage...

  5. Cr3+ and Nb5+ co-doped Ti2Nb10O29 materials for high-performance lithium-ion storage

    Science.gov (United States)

    Yang, Chao; Yu, Shu; Ma, Yu; Lin, Chunfu; Xu, Zhihao; Zhao, Hua; Wu, Shunqing; Zheng, Peng; Zhu, Zi-Zhong; Li, Jianbao; Wang, Ning

    2017-08-01

    Ti2Nb10O29 is an advanced anode material for lithium-ion batteries due to its large specific capacity and high safety. However, its poor electronic/ionic conductivity significantly limits its rate capability. To tackle this issue, a Cr3+-Nb5+ co-doping is employed, and a series of CrxTi2-2xNb10+xO29 compounds are prepared. The co-doping does not change the Wadsley-Roth shear structure but increases the unit-cell volume and decreases the particle size. Due to the increased unit-cell volumes, the co-doped samples show increased Li+-ion diffusion coefficients. Experimental data and first-principle calculations reveal significantly increased electronic conductivities arising from the formation of impurity bands after the co-doping. The improvements of the electronic/ionic conductivities and the smaller particle sizes in the co-doped samples significantly contribute to improving their electrochemical properties. During the first cycle at 0.1 C, the optimized Cr0.6Ti0.8Nb10.6O29 sample delivers a large reversible capacity of 322 mAh g-1 with a large first-cycle Coulombic efficiency of 94.7%. At 10 C, it retains a large capacity of 206 mAh g-1, while that of Ti2Nb10O29 is only 80 mAh g-1. Furthermore, Cr0.6Ti0.8Nb10.6O29 shows high cyclic stability as demonstrated in over 500 cycles at 10 C with tiny capacity loss of only 0.01% per cycle.

  6. ION INJECTION AT QUASI-PARALLEL SHOCKS SEEN BY THE CLUSTER SPACECRAFT

    International Nuclear Information System (INIS)

    Johlander, A.; Vaivads, A.; Khotyaintsev, Yu. V.; Retinò, A.; Dandouras, I.

    2016-01-01

    Collisionless shocks in space plasma are known to be capable of accelerating ions to very high energies through diffusive shock acceleration (DSA). This process requires an injection of suprathermal ions, but the mechanisms producing such a suprathermal ion seed population are still not fully understood. We study acceleration of solar wind ions resulting from reflection off short large-amplitude magnetic structures (SLAMSs) in the quasi-parallel bow shock of Earth using in situ data from the four Cluster spacecraft. Nearly specularly reflected solar wind ions are observed just upstream of a SLAMS. The reflected ions are undergoing shock drift acceleration (SDA) and obtain energies higher than the solar wind energy upstream of the SLAMS. Our test particle simulations show that solar wind ions with lower energy are more likely to be reflected off the SLAMS, while high-energy ions pass through the SLAMS, which is consistent with the observations. The process of SDA at SLAMSs can provide an effective way of accelerating solar wind ions to suprathermal energies. Therefore, this could be a mechanism of ion injection into DSA in astrophysical plasmas

  7. Clusters in Nuclei. Vol. 2

    International Nuclear Information System (INIS)

    Beck, Christian

    2012-01-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This second volume follows the successful Lect. Notes Phys. 818 (Vol.1), and comprises six extensive lectures covering the following topics: - Microscopic cluster models - Neutron halo and break-up reactions - Break-up reaction models for two- and three-cluster projectiles - Clustering effects within the di-nuclear model - Nuclear alpha-particle condensates - Clusters in nuclei: experimental perspectives By promoting new ideas and developments while retaining a pedagogical style of presentation throughout, these lectures will serve as both a reference and an advanced teaching manual for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  8. Clusters in Nuclei. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Christian (ed.) [Strasbourg Univ. (France). Inst. Pluridiciplinaire Hubert Curien

    2012-07-01

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This second volume follows the successful Lect. Notes Phys. 818 (Vol.1), and comprises six extensive lectures covering the following topics: - Microscopic cluster models - Neutron halo and break-up reactions - Break-up reaction models for two- and three-cluster projectiles - Clustering effects within the di-nuclear model - Nuclear alpha-particle condensates - Clusters in nuclei: experimental perspectives By promoting new ideas and developments while retaining a pedagogical style of presentation throughout, these lectures will serve as both a reference and an advanced teaching manual for future courses and schools in the fields of nuclear physics and nuclear astrophysics. (orig.)

  9. Thermodynamic modeling of the formation and stability of small tin clusters and their ions

    International Nuclear Information System (INIS)

    Kodlaa, A.; Suliman, A.

    2005-01-01

    Based on the results of previous quantum-chemical study of electronic structure properties for neutral and single positively and negatively charged thin clusters in the size range of N 2-17 atoms, and on the thermodynamic laws, we have studied the thermodynamic properties of tin clusters and their ions. The characteristic amounts (cohesive enthalpy, formation enthalpy, fragmentation enthalpy, entropy and free enthalpy) for the formation and stability of these clusters at different temperatures were calculated. From the results, which are presented and discussed in this work, one can observe the following: The tin clusters Sn N (N=2-17) and their cations Sn + N and anions Sn - N are formed in the gas phase, and this agrees with experimental results. The clusters Sn 3 and Sn 1 0 are the most stable clusters of all. Here we also, find a correspondence with the results of the experimental studies. Our results go beyond that since we have found Sn 1 5 is also specially stable. By this thermodynamic study we could evaluate approximately the formation and stability of small neutral, single positively and negatively charged tin clusters. It has also allowed us to study the effects of the temperature on the formation and stability of these clusters. The importance of such study is not only what mentioned above, but it is also the first thermodynamic study for modeling the formation and stability of small tin clusters. (author)

  10. Cluster observations of the high-latitude magnetopause and cusp: initial results from the CIS ion instruments

    Directory of Open Access Journals (Sweden)

    J. M. Bosqued

    Full Text Available Launched on an elliptical high inclination orbit (apogee: 19.6 RE since January 2001 the Cluster satellites have been conducting the first detailed three-dimensional studies of the high-latitude dayside magnetosphere, including the exterior cusp, neighbouring boundary layers and magnetopause regions. Cluster satellites carry the CIS ion spectrometers that provide high-precision, 3D distributions of low-energy (<35 keV/e ions every 4 s. This paper presents the first two observations of the cusp and/or magnetopause behaviour made under different interplanetary magnetic field (IMF conditions. Flow directions, 3D distribution functions, density profiles and ion composition profiles are analyzed to demonstrate the high variability of high-latitude regions. In the first crossing analyzed (26 January 2001, dusk side, IMF-BZ < 0, multiple, isolated boundary layer, magnetopause and magnetosheath encounters clearly occurred on a quasi-steady basis for ~ 2 hours. CIS ion instruments show systematic accelerated flows in the current layer and adjacent boundary layers on the Earthward side of the magnetopause. Multi-point analysis of the magnetopause, combining magnetic and plasma data from the four Cluster spacecraft, demonstrates that oscillatory outward-inward motions occur with a normal speed of the order of ± 40 km/s; the thickness of the high-latitude current layer is evaluated to be of the order of 900–1000 km. Alfvénic accelerated flows and D-shaped distributions are convincing signatures of a magnetic reconnection occurring equatorward of the Cluster satellites. Moreover, the internal magnetic and plasma structure of a flux transfer event (FTE is analyzed in detail; its size along the magnetopause surface is ~ 12 000 km and it convects with a velocity of ~ 200 km/s. The second event analyzed (2 February 2001 corresponds to the first Cluster pass within the cusp when the IMF-BZ component was northward directed. The analysis of

  11. SEPARATION OF Fe (III, Cr(III, Cu(II, Ni(II, Co(II, AND Pb(II METAL IONS USING POLY(EUGENYL OXYACETIC ACID AS AN ION CARRIER BY A LIQUID MEMBRANE TRANSPORT METHOD

    Directory of Open Access Journals (Sweden)

    La Harimu

    2010-06-01

    Full Text Available Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II  metal ions had been separated using poly(eugenyl oxyacetic acid as an ion carrier by bulk liquid membrane transport method. The effect of pH, polyeugenyl oxyacetic acid ion carrier concentration, nitric acid concentration in the stripping solution, transport time, and metal concentration were optimized. The result showed that the optimum condition for transport of metal ions was at pH 4 for ion Fe(III and at pH 5 for Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions. The carrier volumes were optimum with concentration of 1 x 10-3 M at 7.5 mL for Cr(III, Cu (II,  Ni(II, Co(II ions and at 8.5 mL for Fe(III and Pb(II ions. The concentration of HNO3 in stripping phase was optimum at 2 M for Fe(III and Cu(II ions, 1 M for Cr(III, Ni(II and Co(II ions, and 0.5 M for Pb(II ion. The optimum transport times were 36 h for Fe(III and Co(II ions, and 48 h for Cr(III, Cu (II, Ni(II, and Pb(II ions. The concentration of metal ions accurately transported were 2.5 x 10-4 M for Fe(III and Cr(III ions, and 1 M for Cu (II, Ni(II, Co(II, and Pb(II ions. Compared to other metal ions the transport of Fe(III was the highest with selectivity order of Fe(III > Cr(III > Pb(II > Cu(II > Ni(II > Co(II. At optimum condition, Fe(III ion was transported through the membrane at 46.46%.   Keywords: poly(eugenyl oxyacetic acid, transport, liquid membrane, Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions

  12. Facile synthesis and electrochemical performance of Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} nanocomposite for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    An, Bonan [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Ru, Qiang, E-mail: ruqiang@scnu.edu.cn [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Hu, Shejun; Song, Xiong; Li, Juan [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China)

    2014-12-15

    Graphical abstract: TEM of Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} composite and the discharge curves of pure Co{sub 3}O{sub 4}, pure Co{sub 2}SnO{sub 4} and Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} composite. - Highlights: • Novel Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} composite has been prepared by simple co-precipitation method. • Small spherical nanocrystals adhering to the surface of large polyhedral particles. • Formation mechanism is relate to solubility of Sn(OH){sub 6}{sup 2−} in high concentration OH{sup −} . • The composite shows better electrochemical performance than Co{sub 2}SnO{sub 4} and Co{sub 3}O{sub 4} - Abstract: A novel dispersed structure Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} composite has been successfully synthesized by a conventional co-precipitation method with certain amount of NaOH concentration. The obtained composite exhibits dispersed structure with small spherical nanocrystals adhering to the surface of large polyhedral particles, which has been studied as an anode material in lithium-ion battery. Galvanostatic charge–discharge and cyclic voltammetry has been conducted to measure the electrochemical properties of the material. The results show that Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} composite demonstrates good reversible capacity of 702.5 mA h g{sup −1} after 50 cycles at a current density of 100 mA h g{sup −1}, much better than that of pure Co{sub 3}O{sub 4} (375.1 mA h g{sup −1}) and pure Co{sub 2}SnO{sub 4} (194.1 mA h g{sup −1}). This material also presents improved rate performance with capacity retention of 71.1% when the current ranges from 100 mA g{sup −1} to 1000 mA g{sup −1}. The excellent electrochemical performance of the as-prepared dispersed structure Co{sub 2}SnO{sub 4}/Co{sub 3}O{sub 4} composite could be attributed to the good dispersibility of nanoparticles which can effectively alleviate the volume expansion and improve the conductivity, thus enhance the cycling stability.

  13. Synthesis of new dithiacobaltaborane clusters derived from arachno-6,8-S2B7H9

    International Nuclear Information System (INIS)

    Kang, S.O.; Sneddon, L.G.

    1988-01-01

    A series of air-stable dithiacobaltaborane clusters has been isolated from either the reaction of the arachno-S 2 B 7 H 8 - anion with cobalt chloride and pentamethylcyclopentadienide or the reaction of neutral arachno-6,8-S 2 B 7 H 9 with cobalt atoms and pentamethylcyclopentadiene. Thus, the reaction of arachno-S 2 B 7 H 8 - with CoCl 2 and C 5 (CH 3 ) 5 - in THF gave, as the major products, the triple-decker compound nido-4,6-η-C 5 (CH 3 ) 52 Co 2 -3,5-S 2 B 2 H 2 (I) and the 11-vertex cluster nido-8,10(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (III). Also isolated in smaller amounts were a chloride derivative of I, nido-1-Cl-4,6-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -3,5-S 2 B 2 H (II), two isomers of III, nido-3,10-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (IV) and nido-3,5-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -7,9-S 2 B 7 H 7 (V), and the eight-boron cluster nido-8-(η-C 5 (CH 3 ) 5 )Co-7,9-S 2 B 8 H 8 (VI). Other trace products of the reaction included the six-boron clusters nido-5,8-(η-C 5 (CH 3 ) 5 ) 2 Co 2 -6,9-S 2 B 6 H 6 (VII) and arachno-7-(η-C 5 (CH 3 ) 5 )Co-6,8-S 2 B 6 H 8 (VIII). Compound III was found to isomerize at 250 degree C to IV, which could then be converted to V at 300 degree C. The reaction of cobalt atoms with arachno-6,8-S 2 B 7 H 9 in the presence of pentamethylcyclopentadiene gave VIII as the major product; however, a number of other clusters including I, V, VI, and [(η-C 5 (CH 3 ) 5 ) 2 Co] + [(SB 10 H 10 ) 2 Co] - were isolated in trace amounts. 16 references, 6 figures, 3 tables

  14. Interaction of ion clusters with fusion plasmas: Scaling laws

    International Nuclear Information System (INIS)

    Arista, N.R.; Bringa, E.M.

    1997-01-01

    The interaction between large ion clusters or very intense ion beams with fusion plasma is studied using the dielectric function formalism with appropriate quantum corrections. The contributions from individual and collective modes to the energy loss are calculated. The general properties of the interference effects are characterized in terms of the relevant parameters, and simple scaling laws are obtained. In particular, the conditions for a maximum enhancement in the energy deposition are derived. The study provides a unified view and a general formulation of collective effects in the energy loss for low and high velocities of the beam particles. copyright 1997 The American Physical Society

  15. Ion-neutral Clustering of Bile Acids in Electrospray Ionization Across UPLC Flow Regimes

    Science.gov (United States)

    Brophy, Patrick; Broeckling, Corey D.; Murphy, James; Prenni, Jessica E.

    2018-02-01

    Bile acid authentic standards were used as model compounds to quantitatively evaluate complex in-source phenomenon on a UPLC-ESI-TOF-MS operated in the negative mode. Three different diameter columns and a ceramic-based microfluidic separation device were utilized, allowing for detailed descriptions of bile acid behavior across a wide range of flow regimes and instantaneous concentrations. A custom processing algorithm based on correlation analysis was developed to group together all ion signals arising from a single compound; these grouped signals produce verified compound spectra for each bile acid at each on-column mass loading. Significant adduction was observed for all bile acids investigated under all flow regimes and across a wide range of bile acid concentrations. The distribution of bile acid containing clusters was found to depend on the specific bile acid species, solvent flow rate, and bile acid concentration. Relative abundancies of each cluster changed non-linearly with concentration. It was found that summing all MS level (low collisional energy) ions and ion-neutral adducts arising from a single compound improves linearity across the concentration range (0.125-5 ng on column) and increases the sensitivity of MS level quantification. The behavior of each cluster roughly follows simple equilibrium processes consistent with our understanding of electrospray ionization mechanisms and ion transport processes occurring in atmospheric pressure interfaces. [Figure not available: see fulltext.

  16. Poly(hydroxyethyl methacrylate-co-methacryloylglutamic acid) nanospheres for adsorption of Cd2+ ions from aqueous solutions

    Science.gov (United States)

    Esen, Cem; Şenay, Raziye Hilal; Feyzioğlu, Esra; Akgöl, Sinan

    2014-02-01

    Poly(2-hydroxyethyl methacrylate-co- N-methacryloyl-( l)-glutamic acid) p(HEMA-MAGA) nanospheres have been synthesized, characterized, and used for the adsorption of Cd2+ ions from aqueous solutions. Nanospheres were prepared by surfactant free emulsion polymerization. The p(HEMA-MAGA) nanospheres were characterized by SEM, FTIR, zeta size, and elemental analysis. The specific surface area of nanospheres was found to be 1,779 m2/g. According to zeta size analysis results, average size of nanospheres is 147.3 nm with poly-dispersity index of 0.200. The goal of this study was to evaluate the adsorption performance of p(HEMA-MAGA) nanospheres for Cd2+ ions from aqueous solutions by a series of batch experiments. The Cd2+ concentration was determined by inductively coupled plasma-optical emission spectrometer. Equilibrium sorption experiments indicated a Cd2+ uptake capacity of 44.2 mg g-1 at pH 4.0 at 25 °C. The adsorption of Cd2+ ions increased with increasing pH and reached a plateau value at around pH 4.0. The data were successfully modeled with a Langmuir equation. A series of kinetics experiments was then carried out and a pseudo-second order equation was used to fit the experimental data. Desorption experiments which were carried out with nitric acid showed that the p(HEMA-MAGA) nanospheres could be reused without significant losses of their initial properties in consecutive adsorption and elution operations.

  17. Adsorption and Formation of Small Na Clusters on Pristine and Double-Vacancy Graphene for Anodes of Na-Ion Batteries.

    Science.gov (United States)

    Liang, Zhicong; Fan, Xiaofeng; Zheng, Weitao; Singh, David J

    2017-05-24

    Layered carbon is a likely anode material for Na-ion batteries (NIBs). Graphitic carbon has a low capacity of approximately 35 (mA h)/g due to the formation of NaC 64 . Using first-principles methods including van der Waals interactions, we analyze the adsorption of Na ions and clusters on graphene in the context of anodes. The interaction between Na ions and graphene is found to be weak. Small Na clusters are not stable on the surface of pristine graphene in the electrochemical environment of NIBs. However, we find that Na ions and clusters can be stored effectively on defected graphene that has double vacancies. In addition, the adsorption energy of small Na clusters near a double vacancy is found to decrease with increasing cluster size. With high concentrations of vacancies the capacity of Na on defective graphene is found to be as much as 10-30 times higher than that of graphitic carbon.

  18. Electron-induced chemistry in microhydrated sulfuric acid clusters

    Science.gov (United States)

    Lengyel, Jozef; Pysanenko, Andriy; Fárník, Michal

    2017-11-01

    We investigate the mixed sulfuric acid-water clusters in a molecular beam experiment with electron attachment and negative ion mass spectrometry and complement the experiment by density functional theory (DFT) calculations. The microhydration of (H2SO4)m(H2O)n clusters is controlled by the expansion conditions, and the electron attachment yields the main cluster ion series (H2SO4)m(H2O)nHSO4- and (H2O)nH2SO4-. The mass spectra provide an experimental evidence for the onset of the ionic dissociation of sulfuric acid and ion-pair (HSO4- ṡ ṡ ṡ H3O+) formation in the neutral H2SO4(H2O)n clusters with n ≥ 5 water molecules, in excellent agreement with the theoretical predictions. In the clusters with two sulfuric acid molecules (H2SO4)2(H2O)n this process starts as early as n ≥ 2 water molecules. The (H2SO4)m(H2O)nHSO4- clusters are formed after the dissociative electron attachment to the clusters containing the (HSO4- ṡ ṡ ṡ H3O+) ion-pair structure, which leads to the electron recombination with the H3O+ moiety generating H2O molecule and the H-atom dissociation from the cluster. The (H2O)nH2SO4- cluster ions point to an efficient caging of the H atom by the surrounding water molecules. The electron-energy dependencies exhibit an efficient electron attachment at low electron energies below 3 eV, and no resonances above this energy, for all the measured mass peaks. This shows that in the atmospheric chemistry only the low-energy electrons can be efficiently captured by the sulfuric acid-water clusters and converted into the negative ions. Possible atmospheric consequences of the acidic dissociation in the clusters and the electron attachment to the sulfuric acid-water aerosols are discussed.

  19. Mining Co-Location Patterns with Clustering Items from Spatial Data Sets

    Science.gov (United States)

    Zhou, G.; Li, Q.; Deng, G.; Yue, T.; Zhou, X.

    2018-05-01

    The explosive growth of spatial data and widespread use of spatial databases emphasize the need for the spatial data mining. Co-location patterns discovery is an important branch in spatial data mining. Spatial co-locations represent the subsets of features which are frequently located together in geographic space. However, the appearance of a spatial feature C is often not determined by a single spatial feature A or B but by the two spatial features A and B, that is to say where A and B appear together, C often appears. We note that this co-location pattern is different from the traditional co-location pattern. Thus, this paper presents a new concept called clustering terms, and this co-location pattern is called co-location patterns with clustering items. And the traditional algorithm cannot mine this co-location pattern, so we introduce the related concept in detail and propose a novel algorithm. This algorithm is extended by join-based approach proposed by Huang. Finally, we evaluate the performance of this algorithm.

  20. Formation of clusters (ions solvated with products of radiolysis) during irradiation of certain chloralkanes in the condensed phase

    International Nuclear Information System (INIS)

    Sukhov, F.F.; Karatun, A.A.; Slovokhotova, N.A.

    1983-01-01

    Using the infrared spectroscopy method, the radiolysis of the 2-chloropropane and 2-chloro-2-methylpropane was investigated in various phase states and in argon matrix at 15 and 77 K. A conclusion is drawn that the reaction of the radiation dehydrochlorination in the chloralkanes investigated occurs under certain conditions in the vicinity of ions, mostly; as this takes place, unique clusters composed of radiolysis products, i.e. ions solvated with complexes of alkane and hydrogen chloride are being formed. (author)

  1. Facile polyol synthesis of CoFe2O4 nanosphere clusters and investigation of their electrochemical behavior in different aqueous electrolytes

    Science.gov (United States)

    Malaie, K.; Ganjali, M. R.; Alizadeh, T.; Norouzi, P.

    2018-04-01

    CoFe2O4 nanosphere clusters (CFNCs) with good crystallinity were synthesized through a facile polyol process without using any surfactant or template. FESEM images show cobalt ferrite clusters with a diameter of 200-400 nm with nanospheres grown on the surface. The electrochemical behavior of the CFNCs was investigated in different electrolytes of KOH, K2SO4, and Na2SO3 in the negative potential window of - 0.3 to - 1.3 V for possible application in supercapacitor electrodes. CFNCs exhibited best performance in KOH electrolyte with a specific capacitance of 151 F g-1 in 5 mV s-1 and a cycling stability of 87% over 1000 voltammetric cycles. These studies indicate the potential application of the as-obtained CFNCs as negative electrodes in alkaline supercapacitors.

  2. Synthesis of LiNi0.65Co0.25Mn0.1O2 as cathode material for lithium-ion batteries by rheological phase method

    International Nuclear Information System (INIS)

    Cheng Cuixia; Tan Long; Hu Anzheng; Liu Haowen; Huang Xintang

    2010-01-01

    Research highlights: → In this paper, for the first time, rheological phase method, a simple and effective route, was applied to synthesis high capacity cathode material LiNi 0.65 Co 0.25 Mn 0.1 O 2 . → All of the results obtained by X-ray diffraction spectrometer, X-ray photoelectron spectrometer, charge-discharge tests and electrochemical impedance spectroscopy show that the rheological phase production have better properties than that of the report. - Abstract: Rheological phase (RP) method has been successfully applied to synthesize a promising cathode material LiNi 0.65 Co 0.25 Mn 0.1 O 2 . X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma and transmission electron microscope are used to investigate the structure, composition and morphology, respectively. XRD result shows that the as-prepared powder has a layered α-NaFeO 2 structure. XPS pattern reveals that the Ni ions have valences of 2+ and 3+, and the Co and Mn are 3+, 4+, respectively. The electrode consisting of the obtained powder presents the better electrochemical properties, which is attributed to the fewer amounts of Ni 2+ ions and the smaller particles. All the results suggest that the rheological phase method is a promising technique for the preparation of LiNi 0.65 Co 0.25 Mn 0.1 O 2 cathode material of lithium-ion batteries.

  3. CoCr wear particles generated from CoCr alloy metal-on-metal hip replacements, and cobalt ions stimulate apoptosis and expression of general toxicology-related genes in monocyte-like U937 cells

    Energy Technology Data Exchange (ETDEWEB)

    Posada, Olga M., E-mail: O.M.PosadaEstefan@leeds.ac.uk [Biomedical Engineering Department, University of Strathclyde, Wolfson Centre, Glasgow G4 0NW (United Kingdom); Gilmour, Denise [Pure and Applied Chemistry Department, University of Strathclyde, Thomas Graham Building, Glasgow G1 1XL (United Kingdom); Tate, Rothwelle J., E-mail: r.j.tate@strath.ac.uk [Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE (United Kingdom); Grant, M. Helen [Biomedical Engineering Department, University of Strathclyde, Wolfson Centre, Glasgow G4 0NW (United Kingdom)

    2014-11-15

    Cobalt-chromium (CoCr) particles in the nanometre size range and their concomitant release of Co and Cr ions into the patients' circulation are produced by wear at the articulating surfaces of metal-on-metal (MoM) implants. This process is associated with inflammation, bone loss and implant loosening and led to the withdrawal from the market of the DePuy ASR™ MoM hip replacements in 2010. Ions released from CoCr particles derived from a resurfacing implant in vitro and their subsequent cellular up-take were measured by ICP-MS. Moreover, the ability of such metal debris and Co ions to induce both apoptosis was evaluated with both FACS and immunoblotting. qRT-PCR was used to assess the effects on the expression of lymphotoxin alpha (LTA), BCL2-associated athanogene (BAG1), nitric oxide synthase 2 inducible (NOS2), FBJ murine osteosarcoma viral oncogene homolog (FOS), growth arrest and DNA-damage-inducible alpha (GADD45A). ICP-MS showed that the wear debris released significant (p < 0.05) amounts of Co and Cr ions into the culture medium, and significant (p < 0.05) cellular uptake of both ions. There was also an increase (p < 0.05) in apoptosis after a 48 h exposure to wear debris. Analysis of qRT-PCR results found significant up-regulation (p < 0.05) particularly of NOS2 and BAG1 in Co pre-treated cells which were subsequently exposed to Co ions + debris. Metal debris was more effective as an inducer of apoptosis and gene expression when cells had been pre-treated with Co ions. This suggests that if a patient receives sequential bilateral CoCr implants, the second implant may be more likely to produce adverse effects than the first one. - Highlights: • Effects of CoCr nanoparticles and Co ions on U937 cells were investigated. • Ions released from wear debris play an important role in cellular response, • Toxicity of Co ions could be related to NO metabolic processes and apoptosis. • CoCr particles were a more effective inducer of apoptosis after cell

  4. Intensities and cross sections of Ne, H2, N2, NO and O2 clusters in a molecular beam, ch. 4

    International Nuclear Information System (INIS)

    Deursen, A.P.J. van; Reuss, J.

    1976-01-01

    Molecular beams of Ne, H 2 , N 2 , NO, and O 2 clusters have been investigated. The temperature and pressure dependence of the ion signals have been measured for masses up to three times the monomer mass. (Auth.)

  5. Assessing Many-Body Effects of Water Self-Ions. I: OH-(H2O) n Clusters.

    Science.gov (United States)

    Egan, Colin K; Paesani, Francesco

    2018-04-10

    The importance of many-body effects in the hydration of the hydroxide ion (OH - ) is investigated through a systematic analysis of the many-body expansion of the interaction energy carried out at the CCSD(T) level of theory, extrapolated to the complete basis set limit, for the low-lying isomers of OH - (H 2 O) n clusters, with n = 1-5. This is accomplished by partitioning individual fragments extracted from the whole clusters into "groups" that are classified by both the number of OH - and water molecules and the hydrogen bonding connectivity within each fragment. With the aid of the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method, this structure-based partitioning is found to largely correlate with the character of different many-body interactions, such as cooperative and anticooperative hydrogen bonding, within each fragment. This analysis emphasizes the importance of a many-body representation of inductive electrostatics and charge transfer in modeling OH - hydration. Furthermore, the rapid convergence of the many-body expansion of the interaction energy also suggests a rigorous path for the development of analytical potential energy functions capable of describing individual OH - -water many-body terms, with chemical accuracy. Finally, a comparison between the reference CCSD(T) many-body interaction terms with the corresponding values obtained with various exchange-correlation functionals demonstrates that range-separated, dispersion-corrected, hybrid functionals exhibit the highest accuracy, while GGA functionals, with or without dispersion corrections, are inadequate to describe OH - -water interactions.

  6. Removal of Ni (II), Co (II) and Pb (II) ions from aqueous media using ...

    African Journals Online (AJOL)

    Removal of Ni (II), Co (II) and Pb (II) ions from aqueous media using Starch ... The results showed that 0.025 % loaded SSMNPs gave the optimal sorption ... constants (Lagergren and Pseudo-2nd-order) for Ni2+ and Co2+ adsorption were ... Langmuir correlation coefficients showed a better fit for the adsorption isotherms.

  7. Reprint of: Negative carbon cluster ion beams: New evidence for the special nature of C60

    Science.gov (United States)

    Liu, Y.; O'brien, S. C.; Zhang, Q.; Heath, J. R.; Tittel, F. K.; Curl, R. F.; Kroto, H. W.; Smalley, R. E.

    2013-12-01

    Cold carbon cluster negative ions are formed by supersonic expansion of a plasma created at the nozzle of a supersonic cluster beam source by an excimer laser pulse. The observed distribution of mass peaks for the Cn- ions for n > 40 demonstrates that the evidence previously given for the special stability of neutral C60 and the existence of spheroidal carbon shells cannot be an artifact of the ionization conditions.

  8. Enhancement of metal-nanoparticle precipitation by co-irradiation of high-energy heavy ions and laser in silica glass

    International Nuclear Information System (INIS)

    Okubo, N.; Umeda, N.; Takeda, Y.; Kishimoto, N.

    2003-01-01

    Simultaneous laser irradiation under ion irradiation is conducted to control nanoparticle precipitation in amorphous (a-)SiO 2 . Copper ions of 3 MeV and photons of 532 nm by Nd:YAG laser are irradiated to substrates of a-SiO 2 . The ion dose rate and total dose are set at 2-10 μA/cm 2 and 3.0 x 10 16 -3.0 x 10 17 ions/cm 2 , respectively, and the laser power density is 0.05-0.2 J/cm 2 pulse at 10 Hz. The laser is simultaneously irradiated with ions in the co-irradiation mode, and the result is compared to that in the sequential and ion-only irradiation. Cross-sectional TEM of the irradiated specimens is conducted after measuring optical absorption spectra. In the case of co-irradiation of intense laser power and high dose (0.2 J/cm 2 pulse and 3.0 x 10 17 ions/cm 2 ), Cu nanoparticles precipitate much more extensively than in the sequential irradiation, increasing both the particle diameter and the total Cu atoms in the nanoparticles. The optical absorption spectra show a surface plasmon peak of the nanoparticles. The precipitation enhancement in the co-irradiation mode suggests that the electronic energy is absorbed by the dynamic electronic states and promotes the Cu precipitation via enhancing the atomic migration

  9. 1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    International Nuclear Information System (INIS)

    Arévalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernández-Maldonado, Arturo J.

    2012-01-01

    The location of extraframework cations in Sr 2+ and Ba 2+ ion-exchanged SAPO-34 was estimated by means of 1 H and 23 Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO 2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO 2 adsorption performance. Highlights: ► Location of extraframework Sr 2+ or Ba 2+ cations was estimated by means of 1 H and 23 Na MAS NMR. ► Level of Sr 2+ or Ba 2+ ion exchange was limited by the presence of protons and sodium cations. ► Presence of ammonium cations in the supercages facilitated the exchange. ► Sr 2+ and Ba 2+ ion exchanged SAPOs are outstanding CO 2 adsorbents.

  10. Defects induced magnetic transition in Co doped ZnS thin films: Effects of swift heavy ion irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Shiv P., E-mail: shivpoojanbhola@gmail.com [Physics Department, University of Allahabad, Allahabad 211002 (India); Pivin, J.C. [CSNSM, IN2P3-CNRS, Batiment 108, F-91405 Orsay Campus (France); Patel, M.K; Won, Jonghan [Materials Science and Technology Division, MST-8, P.O.Box 1663, Mail Stop G755, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chandra, Ramesh [Nanoscience Laboratory, IIC, Indian Institute of Technology, Roorkee 247667 (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kumar, Lokendra [Physics Department, University of Allahabad, Allahabad 211002 (India)

    2012-07-15

    The effect of swift heavy ions (SHI) on magnetic ordering in ZnS thin films with Co ions substituted on Zn sites is investigated. The materials have been synthesized by pulsed laser deposition on substrates held at 600 Degree-Sign C for obtaining films with wurtzite crystal structure and it showed ferromagnetic ordering up to room temperature with a paramagnetic component. 120 MeV Ag ions have been used at different fluences of 1 Multiplication-Sign 10{sup 11} ions/cm{sup 2} and 1 Multiplication-Sign 10{sup 12} ions/cm{sup 2} for SHI induced modifications. The long range correlation between paramagnetic spins on Co ions was destroyed by irradiation and the material became purely paramagnetic. The effect is ascribed to the formation of cylindrical ion tracks due to the thermal spikes resulting from electron-phonon coupling. - Highlights: Black-Right-Pointing-Pointer Effect of swift heavy ions on magnetic ordering in Co doped ZnS thin films are presented. Black-Right-Pointing-Pointer Magnetization in the pristine films is composed of ferromagnetic and paramagnetic components. Black-Right-Pointing-Pointer The films become purely paramagnetic after swift heavy ions irradiation. Black-Right-Pointing-Pointer The magnetic transition is ascribed to the formation of ion track (or cylindrical defects) due to the thermal spikes.

  11. Structure and dynamics of ion clusters in linear octupole traps: Phase diagrams, chirality, and melting mechanisms

    International Nuclear Information System (INIS)

    Yurtsever, E.; Onal, E. D.; Calvo, F.

    2011-01-01

    The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.

  12. CO2 sequestration using principles of shell formation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Woo; Jang, Young-Nam [CO2 Sequestration Research Department, Korea Institute of Geoscience and Mineral Resources (Korea, Republic of); Lee, Si-Hyun; Lim, Kyoung-Soo; Jeong, Soon-Kwan [Energy Conservation Research Department of Clean Energy System Research Center, Korea Institute of Energy Research (Korea, Republic of)

    2011-06-15

    The biomimetic sequestration of carbon dioxide to reduce the CO2 emitted into the atmosphere is introduced in this paper. Bivalve shells are used as a good model of CO2 sequestration in this paper, because the shell is derived from the calcium ions and CO2 in seawater. Carbonic anhydrase, hemocyte from diseased shell (HDS) and extrapallial fluid (EFP) are involved in shell formation. This paper compares the soluble protein extracted from Crassostrea gigas with bovine carbonic anhydrase II in terms of their ability to promote CO2 hydration and the production of calcium precipitates. The result demonstrates that HDS has more functional groups to bind calcium ions in aqueous systems, and a different process of calcium precipitation, than does bovine carbonic anhydrase II. To understand molecular weight and secondary protein structure, mass-spectroscopic analysis (MALDI-TOF) and circular dichroism (CD) analysis were used. With regard to EPF, EPF related to shell formation is composed of several fractions and plays a role in sequestration of CO2.

  13. Ag clustering investigation in laser irradiated ion-exchanged glasses by optical and vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trave, E., E-mail: enrico.trave@unive.it [Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venezia, Dorsoduro 2137, I-30123 Venezia (Italy); Cattaruzza, E.; Gonella, F.; Calvelli, P. [Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venezia, Dorsoduro 2137, I-30123 Venezia (Italy); Quaranta, A. [Department of Materials Engineering and Industrial Technologies, University of Trento, via Mesiano 77, I-38050 Povo (Italy); Rahman, A.; Mariotto, G. [Department of Computer Science, University of Verona, Strada le Grazie 15, 37134 Verona (Italy)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We modify the properties of Ag{sup +} exchanged glasses by thermal and laser treatment. Black-Right-Pointing-Pointer The induced microstructural changes are analyzed by optical and Raman spectroscopy. Black-Right-Pointing-Pointer Ag-based species in the glass show a peculiar PL activity in the UV-Vis range. Black-Right-Pointing-Pointer Raman and OA analysis allow for determining the Ag cluster size evolution. Black-Right-Pointing-Pointer Laser processing leads to different cluster formation and fragmentation mechanisms. - Abstract: Ion exchange process is widely used to dope silicate glass layers with silver for several applications, ranging from light waveguide to nanostructured composite glass fabrication. The silver-doped structure and its physical properties depend on the preparation parameters as well as on subsequent treatments. In particular, laser irradiation of the ion exchanged glasses has been demonstrated to be an effective tool to control cluster size and size distribution. Nevertheless, a complete comprehension of the basic phenomena and a systematic characterization of these systems are still lacking. In this paper, an extended optical characterization is presented for soda-lime glass slides, doped with silver by Ag{sup +}-Na{sup +} ion exchange, thermally treated and irradiated with a Nd:YAG laser beam at different wavelengths, and for different energy density. The samples were characterized by various spectroscopic techniques, namely, optical absorption, photoluminescence and micro-Raman analysis. The availability of all these characterization techniques allowed pointing out a suitable scenario for the Ag clustering evolution as a function of the ion exchange, annealing and laser irradiation parameters.

  14. Revealing dynamically-organized receptor ion channel clusters in live cells by a correlated electric recording and super-resolution single-molecule imaging approach.

    Science.gov (United States)

    Yadav, Rajeev; Lu, H Peter

    2018-03-28

    The N-methyl-d-aspartate (NMDA) receptor ion-channel is activated by the binding of ligands, along with the application of action potential, important for synaptic transmission and memory functions. Despite substantial knowledge of the structure and function, the gating mechanism of the NMDA receptor ion channel for electric on-off signals is still a topic of debate. We investigate the NMDA receptor partition distribution and the associated channel's open-close electric signal trajectories using a combined approach of correlating single-molecule fluorescence photo-bleaching, single-molecule super-resolution imaging, and single-channel electric patch-clamp recording. Identifying the compositions of NMDA receptors, their spatial organization and distributions over live cell membranes, we observe that NMDA receptors are organized inhomogeneously: nearly half of the receptor proteins are individually dispersed; whereas others exist in heterogeneous clusters of around 50 nm in size as well as co-localized within the diffraction limited imaging area. We demonstrate that inhomogeneous interactions and partitions of the NMDA receptors can be a cause of the heterogeneous gating mechanism of NMDA receptors in living cells. Furthermore, comparing the imaging results with the ion-channel electric current recording, we propose that the clustered NMDA receptors may be responsible for the variation in the current amplitude observed in the on-off two-state ion-channel electric signal trajectories. Our findings shed new light on the fundamental structure-function mechanism of NMDA receptors and present a conceptual advancement of the ion-channel mechanism in living cells.

  15. Theoretical insight into Cobalt subnano-clusters adsorption on α-Al{sub 2}O{sub 3} (0001)

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fen-e [College of Chemical Engineering and Environment, North University of China, 030051 Taiyuan (China); Ren, Jun, E-mail: jun.ren@nuc.edu.cn [College of Chemical Engineering and Environment, North University of China, 030051 Taiyuan (China); Wang, Qiang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 030001 Taiyuan (China); Li, Debao, E-mail: dbli@sxicc.ac.cn [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 030001 Taiyuan (China); Hou, Bo; Jia, Litao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 030001 Taiyuan (China); Cao, Duanlin [College of Chemical Engineering and Environment, North University of China, 030051 Taiyuan (China)

    2017-02-15

    The investigation on the structural stability, nucleation, growth and interaction of cobalt cluster Con(n=2–7) on the α-Al{sub 2}O{sub 3}(0001) surface by using density functional theory methods has been reported. Energetically, the most favorable adsorption sites were identified and the strongest adsorption energy cluster is the tetrahedral Co{sub 4} cluster. On the other hand, the nucleation of Con(n=2–7) clusters on the surface is exothermic and thermodynamically favorable. Moreover, even-odd alternation was found with respect to clusters nucleation as a function of the number of cobalt atoms (for n=1–7). Meanwhile, the Co{sub n} clusters can be adsorbed on the surface stably owing to the charge transfer from Co atoms to Al and O atoms of the Al{sub 2}O{sub 3} substrate. In addition, we establish the crucial importance of monomer, dimer and trimer diffusion on the surface. The diffusion of the monomer cobalt from Al{sup (3)} to O{sup (5)} or O{sup (5)} to Al{sup (4)} site is quite easy on the Al{sub 2}O{sub 3}(0001) surface, whereas the diffusion of the Co{sub 2} dimer is thermodynamically unfavorable by compared with that of the Co adatom and Co{sub 3} trimer. - Graphical abstract: Diffusion process of Co adatom on the α-Al{sub 2}O{sub 3} (0001) surface, Al{sup (3)} site→O{sup (5)} site→Al{sup (4)} site. Potential energy surface for diffusion of a single Co atom from Al{sup (3)} to O{sup (5)} site, and from O{sup (5)} to Al{sup (4)} site on the surface. The activation energy of the two migration processes from Al{sup (3)} to O{sup (5)} and O{sup (5)} to Al{sup (4)} are 0.06 and 0.09 eV, respectively. This implies the monomer is quite mobile on the surface under typical growth conditions.

  16. Spatial distribution of ion energy related on electron density in a plasma channel generated in gas clusters by a femtosecond laser

    International Nuclear Information System (INIS)

    Nam, S. M.; Han, J. M.; Cha, Y. H.; Lee, Y. W.; Rhee, Y. J.; Cha, H. K.

    2008-01-01

    Neutron generation through Coulomb explosion of deuterium contained gas clusters is known as one of the very effective methods to produce fusion neutrons using a table top terawatt laser. The energy of ions produced through Coulomb explosions is very important factor to generate neutrons efficiently. Until the ion energy reaches around∼MeV level, the D D fusion reaction probability increases exponentially. The understanding of laser beam propagation and laser energy deposition in clusters is very important to improve neutron yields. As the laser beam propagates through clusters medium, laser energy is absorbed in clusters by ionization of molecules consisting clusters. When the backing pressure of gas increases, the average size of clusters increases and which results in higher energy absorption and earlier termination of laser propagation. We first installed a Michelson interferometer to view laser beam traces in a cluster plume and to measure spatial electron density profiles of a plasma channel which was produced by a laser beam. And then we measured the energy of ions distributed along the plasma channel with a translating slit to select ions from narrow parts of a plasma channel. In our experiments, methane gas was used to produce gas clusters at a room temperature and the energy distribution of proton ions for different gas backing pressure were measured by the time of flight method using dual micro channel plates. By comparing the distribution of ion energies and electron densities, we could understand the condition for effective laser energy delivery to clusters

  17. Modification of WC-Co Hard Metal by Ion Implantation with Ti+, AI+, N+, C+ and B+

    International Nuclear Information System (INIS)

    Rassoul, El.M.A.; Saleh, Z.A.; Waheed, A.F.; Abdel- Samad, S.M.; EI- Awadi, G.A.

    2010-01-01

    WC/Co hard metal was implanted by Ti + , AI + , N + , C + , and B + ions at a dose of 5x 10 17 ions/cm 2 at different energies ranging from 50 keV to 200 keV. The implanted layers were investigated by means of nano indentation, calotte measurements, SEM, X-ray diffraction XRD, tribometer and EDX. The maximum implanted zone was about 0.13 μm. The hardness of WC-Co was increased by a factor of 140% after its implantation by Ti, AI, and N and increased by a factor of 170 % after implantation by Ti + , AI + , C + , N + and B + ions as compared to the original value. Also friction coefficient of WC/Co was improved after ion implantation.

  18. The origin of the selectivity and activity of ruthenium-cluster catalysts for fuel-cell feed-gas purification: a gas-phase approach.

    Science.gov (United States)

    Lang, Sandra M; Bernhardt, Thorsten M; Krstić, Marjan; Bonačić-Koutecký, Vlasta

    2014-05-19

    Gas-phase ruthenium clusters Ru(n)(+) (n=2-6) are employed as model systems to discover the origin of the outstanding performance of supported sub-nanometer ruthenium particles in the catalytic CO methanation reaction with relevance to the hydrogen feed-gas purification for advanced fuel-cell applications. Using ion-trap mass spectrometry in conjunction with first-principles density functional theory calculations three fundamental properties of these clusters are identified which determine the selectivity and catalytic activity: high reactivity toward CO in contrast to inertness in the reaction with CO2; promotion of cooperatively enhanced H2 coadsorption and dissociation on pre-formed ruthenium carbonyl clusters, that is, no CO poisoning occurs; and the presence of Ru-atom sites with a low number of metal-metal bonds, which are particularly active for H2 coadsorption and activation. Furthermore, comprehensive theoretical investigations provide mechanistic insight into the CO methanation reaction and discover a reaction route involving the formation of a formyl-type intermediate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Cluster-assistant generation of multiply charged atomic ions in nanosecond laser ionization of seeded methyl iodide beam

    International Nuclear Information System (INIS)

    Luo Xiaolin; Niu Dongmei; Kong Xianglei; Wen Lihua; Liang Feng; Pei Kemei; Wang Bin; Li Haiyang

    2005-01-01

    The photoionization of methyl iodide beam seeded in argon and helium is studied by time-of-flight mass spectrometry using a 25 ns, 532 nm Nd-YAG laser with intensities in the range of 2 x 10 10 -2 x 10 11 W/cm 2 . Multiply charged ions of I q+ (q = 2-3) and C 2+ with tens of eV kinetic energies have been observed when laser interacts with the middle part of the pulsed molecular beam, whose peak profiles are independent on the laser polarization directions. Strong evidences show that these ions are coming from the Coulomb explosion of multiply charged CH 3 I clusters, and laser induced inverse bremsstrahlung absorption of caged electrons plays a key role in the formation of multiply charged ions

  20. Magnetic characterization of mixed phases in FeVO4sbnd Co3V2O8 system

    Science.gov (United States)

    Guskos, N.; Zolnierkiewicz, G.; Pilarska, M.; Typek, J.; Berczynski, P.; Blonska-Tabero, A.; Aidinis, K.

    2018-04-01

    Dynamic and static magnetic properties of four nFeVO4/(1-n)Co3V2O8 composites obtained in reactions between nFeVO4 and (1-n)Co3V2O8 (n = 0.82, 0.80, 0.78 and 0.76) have been investigated by dc magnetometry and electron paramagnetic resonance (EPR). All samples were diphase containing both the howardevansite-type and the lyonsite-type phases in different proportions. Dc magnetic susceptibility study showed the Curie-Weiss paramagnetic behavior with strong antiferromagnetic (AFM) interaction in the high-temperature range and the phase transition to the AFM state at low temperatures. The calculated effective magnetic moment could be justified by the presence of high spin Fe3+ and Co2+ ions. The appearance of hysteresis loop in isothermal magnetisation at low temperature indicates the existence of the ferromagnetic component in all four samples, but only 0.5% of all magnetic ions are involved in this phase. EPR spectra recorded in high-temperature range (T > 90 K) consisted of a single broad line centred at ∼3.2 kG. The fitting of observed spectra with two Gaussian lineshape functions allowed to study the temperature dependence of EPR parameters (resonance field, linewidth, integrated intensity). This analysis suggests that EPR signal arises from two spin subsystems: paramagnetic Fe3+ ions subjected to AFM interaction and AFM spin pairs/clusters of iron/cobalt visible only at high temperatures. At low temperatures two transitions to AFM states, due to the mixture of two structural phases, are registered in magnetic susceptibility measurements.

  1. Magnetism, structure and chemical order in small CoPd clusters: A first-principles study

    KAUST Repository

    Mokkath, Junais Habeeb

    2014-01-01

    The structural, electronic and magnetic properties of small ComPdn (N=m+n=8,m=0-N) nanoalloy clusters are studied in the framework of a generalized-gradient approximation to density-functional theory. The optimized cluster structures have a clear tendency to maximize the number of nearest-neighbor CoCo pairs. The magnetic order is found to be ferromagnetic-like (FM) for all the ground-state structures. Antiferromagnetic-like spin arrangements were found in some low-lying isomers. The average magnetic moment per atom μ̄N increases approximately linearly with Co content. A remarkable enhancement of the local Co moments is observed as a result of Pd doping. This is a consequence of the increase in the number of Co d holes, due to CoPd charge transfer, combined with the reduced local coordination. The influence of spin-orbit interactions on the cluster properties is also discussed. © 2013 Elsevier B.V.

  2. Synthesis of Li{sub 2}Si{sub 2}O{sub 5}-coated LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} cathode materials with enhanced high-voltage electrochemical properties for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shengjie; Wu, Hao; Huang, Ling; Xiang, Mingwu; Liu, Heng; Zhang, Yun, E-mail: y_zhang@scu.edu.cn

    2016-07-25

    Ni-rich ternary layered oxides, (LiNi{sub x} [M]{sub 1−x}O{sub 2}, x ≥ 0.5, M = Co and Mn), have become one of the mainstream cathode materials for next-generation lithium-ion batteries due to their high capacity and cost efficiency compared with LiCoO{sub 2}. However, the high-voltage operation of the Ni-rich oxides (>4.3 V) required for high capacity is inevitably accompanied with a rapid capacity decay over numerous cycles. In this work, we reported a surface coating of LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} with Li{sub 2}Si{sub 2}O{sub 5}via a facile and efficient synthetic approach, which involves the employment of silicic acid (H{sub 2}SiO{sub 3}) as remover to react with the surface residual lithium compounds (e.g. Li{sub 2}CO{sub 3} and LiOH) of LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} and consequent formation of a robust and complete Li{sup +}-conductive Li{sub 2}Si{sub 2}O{sub 5} protective coating layer. The structure and morphology of the coated cathode materials are fully characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Compared with the pristine LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2}, coating with the Li{sup +}-conductive Li{sub 2}Si{sub 2}O{sub 5} is found to be very effective for improving the rate capability of the LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} when evaluated at a high cut-off voltage up to 4.5 V. Specifically, 1 wt. % H{sub 2}SiO{sub 3}-treated LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} electrode exhibits high discharge specific capacities of 213.9 and 121.6 mAh g{sup −1} at 0.1 and 10 C, respectively, whereas the pristine electrode only shows 196.8 and 92.1 mAh g{sup −1}. Besides, the surface-modified LiNi{sub 0.6}Co{sub 0.2}Mn{sub 0.2}O{sub 2} electrode also manifests an enhanced long-term cycling stability (67% capacity retention after 200 cycles at 5 C), much better than the pristine

  3. Synthesis and characterization of BaAl{sub 2}O{sub 4}:Eu{sup 2+} co-doped with different rare earth ions

    Energy Technology Data Exchange (ETDEWEB)

    Lephoto, M.A. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Ntwaeaborwa, O.M., E-mail: ntwaeab@ufs.ac.za [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Pitale, Shreyas S.; Swart, H.C. [Department of Physics, University of the Free State, Private bag X 13, Phuthaditjaba 9866, P.O. Box 339, Bloemfontein, ZA 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth, ZA 6031 (South Africa); Mothudi, B.M. [Department of Physics, University of South Africa, P.O Box 392, Pretoria, ZA 6031 (South Africa)

    2012-05-15

    Combustion method was used in this study to prepare BaAl{sub 2}O{sub 4}:Eu{sup 2+} phosphors co-doped with different trivalent rare-earths (Re{sup 3+}=Dy{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Sm{sup 3+}, Ce{sup 3+}, Er{sup 3+}, Pr{sup 3+} and Tb{sup 3+}) ions at an initiating temperature of 600 Degree-Sign C. The phosphors were annealed at 1000 Degree-Sign C for 3 h. As confirmed from the X-ray diffraction (XRD) data, both as prepared and post annealed samples crystallized in the well known hexagonal structure of BaAl{sub 2}O{sub 4}. All samples exhibited bluish-green emission associated with the 4f{sup 6}5d{sup 1}{yields}4f{sup 7} transitions of Eu{sup 2+} at {approx}500 nm. Although the highest intensity was observed from Er{sup 3+} co-doping, the longest afterglow (due to trapping and detrapping of charge carriers) was observed from Nd{sup 3+} followed by Dy{sup 3+} co-doping. The traps responsible for the long afterglow were studied using thermoluminescence (TL) spectroscopy.

  4. Low temperature synthesis of layered NaxCoO2 and KxCoO2 from ...

    Indian Academy of Sciences (India)

    Unknown

    Layered oxides have interesting chemical and physical properties. .... composition of these crystalline phases were obtained from scanning electron microscopy ... 2.2a Cobalt estimation: About 50 mg of the compound was dissolved in 10 ml of 6 M ... images of the parent Na0⋅2CoO2 and those ion exchanged with H+, Li+ ...

  5. Experimental study of the dissociation of 100-600 KeV hydrogen cluster ions in an argon gas target

    International Nuclear Information System (INIS)

    Chevallier, M.; Clouvas, A.; Frischkorn, H.J.; Gaillard, M.J.; Poizat, J.C.; Remillieux, J.

    1985-09-01

    We have studied the break-up of accelerated hydrogen cluster ions passing through an argon gas target. The absolute dissociation cross section has been measured for a wide variety of H n + (odd masses only) cluster ions, with n between 5 and 23 and with projectile velocities ranging from 1.5 to 5 x 10 8 cm/s. We discuss the dissociation processes and the dependence of their cross-sections upon the cluster mass and velocity

  6. Gold chloride clusters with Au(III) and Au(I) probed by FT-ICR mass spectrometry and MP2 theory.

    Science.gov (United States)

    Lemke, Kono H

    2014-05-07

    Microsolvated clusters of gold chloride are probed by electrospray ionization mass spectrometry (ESI-MS) and scalar relativistic electronic structure calculations. Electrospray ionization of aqueous AuCl3 leads to mononuclear clusters of types [AuCl2](+)(H2O)n (n = 0-4), [AuOHCl](+)(H2O)n (n = 0-1) and [AuCl2](+)(HCl)2(H2O)n (n = 0-4). In addition, strong ion signals due to dinuclear [Au2Cl5-xOHx](+)(H2O)n (x = 0-1) are present in ESI mass spectra of aqueous AuCl3, with the abundance of individual dinuclear species controlled by the concentration-dependent variation of the precursor complexes [AuCl2-xOHx](+)(H2O)n and AuCl3. Equilibrium structures, energies and thermodynamic properties of mono- and dinuclear gold clusters have been predicted using MP2 and CCSD(T) theory, and these data have been applied to examine the influence of microsolvation on cluster stability. Specifically, results from CCSD(T) calculations indicate that non-covalently bound ion-neutral complexes Au(+)(Cl2)(H2O)n, with formal Au(I), are the dominant forms of mononuclear gold with n = 0-2, while higher hydrates (n > 2) are covalently bound [AuCl2](+)(H2O)n complexes in which gold exists as Au(III). MP2 calculations show that the lowest energy structure of dinuclear gold is an ion-molecule cluster [Au2Cl(Cl2)2](+) consisting of a single-bridged digold-chloronium ion bound end-on to two dichlorine ligands, with two higher energy isomers, single-bridged [Au2Cl3(Cl2)](+) and double-bridged [Au2Cl5](+) clusters. Finally, AuAu interactions in the singly-bridged clusters [Au2Cl(Cl2)2](+)(H2O)n and [Au2Cl3(Cl2)](+)(H2O)n are examined employing a wide range of computational tools, including natural bond order (NBO) analysis and localized orbital locator (LOL) profiles.

  7. Acetylene Black Induced Heterogeneous Growth of Macroporous CoV2O6 Nanosheet for High-Rate Pseudocapacitive Lithium-Ion Battery Anode.

    Science.gov (United States)

    Zhang, Lei; Zhao, Kangning; Luo, Yanzhu; Dong, Yifan; Xu, Wangwang; Yan, Mengyu; Ren, Wenhao; Zhou, Liang; Qu, Longbing; Mai, Liqiang

    2016-03-23

    Metal vanadates suffer from fast capacity fading in lithium-ion batteries especially at a high rate. Pseudocapacitance, which is associated with surface or near-surface redox reactions, can provide fast charge/discharge capacity free from diffusion-controlled intercalation processes and is able to address the above issue. In this work, we report the synthesis of macroporous CoV2O6 nanosheets through a facile one-pot method via acetylene black induced heterogeneous growth. When applied as lithium-ion battery anode, the macroporous CoV2O6 nanosheets show typical features of pseudocapacitive behavior: (1) currents that are mostly linearly dependent on sweep rate and (2) redox peaks whose potentials do not shift significantly with sweep rate. The macroporous CoV2O6 nanosheets display a high reversible capacity of 702 mAh g(-1) at 200 mA g(-1), excellent cyclability with a capacity retention of 89% (against the second cycle) after 500 cycles at 500 mA g(-1), and high rate capability of 453 mAh g(-1) at 5000 mA g(-1). We believe that the introduction of pseudocapacitive properties in lithium battery is a promising direction for developing electrode materials with high-rate capability.

  8. Removal of Cs+, Sr2+, and Co2+ ions from the mixture of organics and suspended solids aqueous solutions by zeolites

    International Nuclear Information System (INIS)

    Fang, Xiang Hong; Fang, Fang; Lu, Chun Hai; Zheng, Lei

    2017-01-01

    Serving as an excellent adsorbent and inorganic ion exchanger in the water purification field, zeolite 4A has in this work presented a strong capability for purifying radioactive waste, such as Sr 2+ , Cs + , and Co 2+ in water. During the processes of decontamination and decommissioning of suspended solids and organics in low-level radioactive wastewater, the purification performance of zeolite 4A has been studied. Under ambient temperature and neutral condition, zeolite 4A absorbed simulated radionuclides such as Sr 2+ , Cs + , and Co 2+ with an absorption rate of almost 90%. Additionally, in alkaline condition, the adsorption percentage even approached 98.7%. After conducting research on suspended solids and organics of zeolite 4A for the treatment of radionuclides, it was found that the suspended clay was conducive to absorption, whereas the absorption of organics in solution was determined by the species of radionuclides and organics. Therefore, zeolite 4A has considerable potential in the treatment of radioactive wastewater

  9. Detecting space-time disease clusters with arbitrary shapes and sizes using a co-clustering approach

    Directory of Open Access Journals (Sweden)

    Sami Ullah

    2017-11-01

    Full Text Available Ability to detect potential space-time clusters in spatio-temporal data on disease occurrences is necessary for conducting surveillance and implementing disease prevention policies. Most existing techniques use geometrically shaped (circular, elliptical or square scanning windows to discover disease clusters. In certain situations, where the disease occurrences tend to cluster in very irregularly shaped areas, these algorithms are not feasible in practise for the detection of space-time clusters. To address this problem, a new algorithm is proposed, which uses a co-clustering strategy to detect prospective and retrospective space-time disease clusters with no restriction on shape and size. The proposed method detects space-time disease clusters by tracking the changes in space–time occurrence structure instead of an in-depth search over space. This method was utilised to detect potential clusters in the annual and monthly malaria data in Khyber Pakhtunkhwa Province, Pakistan from 2012 to 2016 visualising the results on a heat map. The results of the annual data analysis showed that the most likely hotspot emerged in three sub-regions in the years 2013-2014. The most likely hotspots in monthly data appeared in the month of July to October in each year and showed a strong periodic trend.

  10. Morphology-controlled synthesis and electrochemical performance of NiCo{sub 2}O{sub 4} as anode material in lithium-ion battery application

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Shan; Lu, Lin; Zhang, Qing; Zheng, Hao; Liu, Lian; Yin, Shengyu; Wang, Shiquan, E-mail: wsqhao@126.com; Li, Guohua; Feng, Chuanqi [Hubei University, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for Synthesis and Applications of Organic Functional Molecules (China)

    2015-09-15

    Mixed-valence oxide precursors were synthesized by a solvothermal method using NiSO{sub 4}, CoSO{sub 4}, and NH{sub 4}HCO{sub 3} as raw materials. The precursors were heat-treated in a muffle furnace at 500 °C to obtain the products (NiCo{sub 2}O{sub 4}). The samples were characterized by X-ray diffractometer, thermogravimetric, energy-dispersive spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results show that dumbbells, microspheres, and particle-like NiCo{sub 2}O{sub 4} were successfully synthesized by changing the volume of solvent and solvothermal temperature. The NiCo{sub 2}O{sub 4} microspheres (prepared at 180 °C with 30 ml solvent) as anode material for lithium-ion battery, exhibit a reversible discharge capacity of 1160 mAh g{sup −1} and good cycling stability (729 mAh g{sup −1} after 50 cycles) at a constant current of 100 mA g{sup −1} in the voltage range of 0.01–3.0 V due to its high crystallinity and uniform porous morphology. Hence, the synthetic method could be extended to other high-capacity ternary metal oxide materials for lithium-ion battery application.

  11. Cluster observations of trapped ions interacting with magnetosheath mirror modes

    Directory of Open Access Journals (Sweden)

    J. Soucek

    2011-06-01

    Full Text Available Mirror modes are among the most intense low frequency plasma wave phenomena observed in the magnetosheaths of magnetized planets. They appear as large amplitude non-propagating fluctuations in the magnetic field magnitude and plasma density. These structures are widely accepted to represent a non-linear stage of the mirror instability, dominant in plasmas with large ion beta and a significant ion temperature anisotropy T⊥/T∥>1. It has long been recognized that the mirror instability both in the linear and non-linear stage is a kinetic process and that the behavior of resonant particles at small parallel velocities is crucial for its development and saturation. While the dynamics of the instability and the effect of trapped particles have been studied extensively in theoretical models and numerical simulations, only spurious observations of the trapped ions were published to date. In this work we used data from the Cluster spacecraft to perform the first detailed experimental study of ion velocity distribution associated with mirror mode oscillations. We show a conclusive evidence for the predicted cooling of resonant ions at small parallel velocities and heating of trapped ions at intermediate pitch angles.

  12. A study of CO2 precipitation method considering an ionic CO2 and Ca(OH)2 slurry

    International Nuclear Information System (INIS)

    Park, Sangwon; Jo, Hoyong; Kang, Dongwoo; Park, Jinwon

    2014-01-01

    CCS (carbon capture and storage) is the most popular technology used for the reduction of CO 2 in the post-combustion stage. However, the CCS process has some disadvantages including uncertainty about the stability of the land that is used to store the separated CO 2 . Consequently, CCU (carbon capture and utilization) technologies have recently received increased attention as a possible replacement for CCS. In this study, we utilized CO 2 fixation methods by using the metal carbonate mechanism. We selected 5 and 30 wt% MEA (mono-ethanolamine) solutions to rapidly make a carbonate and Ca(OH) 2 slurry. In all of the experiments, normal temperature and pressure conditions were maintained (except during desorption to check for residual CO 2 in the MEA solution). Consequently, most of the CO 2 was converted to carbonate. The MEA converted CO 2 to ionic CO 2 and rapidly created calcium carbonate. Also the formed solids that were observed were determined to be CaCO 3 and Ca(OH) 2 by X-ray diffractometry. Also, the MEA solution could be reused to absorb CO 2 . Therefore, we have confirmed the development of our suggested CCS process. This process has the ability not only to reuse emitted CO 2 , but it can also be employed to reuse construction wastes that include heavy metals. - Highlights: • We propose novel CO 2 conversion technology by utilizing an amine solution. • In this study, alkaline solutions were used to produce CO 2 precipitate. • The MEA (mono-ethanolamine) solution has a sufficient potential to fix CO 2 with metal sources under moderate condition. • Also, the Ca(OH) 2 slurry yielded enough Ca 2+ ions to make carbonate

  13. Correction of mass spectrometric isotope ratio measurements for isobaric isotopologues of O2, CO, CO2, N2O and SO2.

    Science.gov (United States)

    Kaiser, Jan; Röckmann, Thomas

    2008-12-01

    Gas isotope ratio mass spectrometers usually measure ion current ratios of molecules, not atoms. Often several isotopologues contribute to an ion current at a particular mass-to-charge ratio (m/z). Therefore, corrections have to be applied to derive the desired isotope ratios. These corrections are usually formulated in terms of isotope ratios (R), but this does not reflect the practice of measuring the ion current ratios of the sample relative to those of a reference material. Correspondingly, the relative ion current ratio differences (expressed as delta values) are first converted into isotopologue ratios, then into isotope ratios and finally back into elemental delta values. Here, we present a reformulation of this data reduction procedure entirely in terms of delta values and the 'absolute' isotope ratios of the reference material. This also shows that not the absolute isotope ratios of the reference material themselves, but only product and ratio combinations of them, are required for the data reduction. These combinations can be and, for carbon and oxygen have been, measured by conventional isotope ratio mass spectrometers. The frequently implied use of absolute isotope ratios measured by specially calibrated instruments is actually unnecessary. Following related work on CO2, we here derive data reduction equations for the species O2, CO, N2O and SO2. We also suggest experiments to measure the required absolute ratio combinations for N2O, SO2 and O2. As a prelude, we summarise historic and recent measurements of absolute isotope ratios in international isotope reference materials. Copyright 2008 John Wiley & Sons, Ltd.

  14. Fragmentation of CO2 into C+ + O+ + O, in collisions with protons

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.

    2000-01-01

    The fragmentation of CO 2 has been investigated in 25 keV H + + CO 2 collisions using an electron-ion-ion triple coincidence technique. In this letter we focus on the three-body fragmentation into the C + + O + + O final state. A comparison between the measured correlation of C + ,O + and O momenta and simple kinematic models allows us to demonstrate that in the present case, a rather unexpected two-step process with formation of a CO 2+ ion as an intermediate state occurs. This result is at variance with the conclusions of other authors achieved in collisions of photons and electrons with the dioxide molecule. Kinetic energy release distributions in the two steps of the dissociation process are also deduced from experiment; the distributions found for the fragmentation of CO 2+ into C + + O + are found to be very similar to those measured by other authors in collisions of various particles (photons, multi-charged ions) with CO molecules at high enough collision energy. (author). Letter-to-the-editor

  15. Charge-sign-clustering observed in high-multiplicity, high-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Takahashi, Y.; Gregory, J.C.; Hayashi, T.

    1989-01-01

    Charge-sign distribution in 200 GeV/amu heavy-ion collisions is studied with the Magnetic-Interferometric-Emulsion-Chamber (MAGIC) for central collision events in 16 O + Pb and 32 S + Pb interactions. Charge-sign clustering is observed in most of the fully-analyzed events. A statistical 'run-test' is performed for each measured event, which shows significant deviation from a Gaussian distribution (0,1) expected for random-charge distribution. Candidates of charge clusters have 5 - 10 multiplicity of like-sign particles, and are often accompanied by opposite-sign clusters. Observed clustering of identical charges is more significant in the fragmentation region than in the central region. Two-particle Bose-Einstein interference and other effects are discussed for the run-test examination. (author)

  16. Loading clusters composed of nanoparticles on ZrO{sub 2} support via a perovskite-type oxide of La{sub 0.95}Ce{sub 0.05}Co{sub 0.7}Cu{sub 0.3}O{sub 3} for ethanol synthesis from syngas and its structure variation with reaction time

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zhaoyu [Tianjin Key Laboratory of Applied Catalysis Science and Technology, School of Chemical Engineering, Tianjin University, Tianjin 300354 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300354 (China); Shi, Xiangpeng [Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300354 (China); Key Laboratory of Green Chemical Technology of Ministry of Education, School