Sample records for kev fullerene bombardment

  1. Probability of self-healing in damaged graphene bombarded by fullerene

    NASA Astrophysics Data System (ADS)

    Xu, Zhi-Cheng; Zhong, Wei-Rong

    2014-06-01

    Using non-equilibrium molecular dynamics method, we study the self-healing behavior of graphene after bombarded by fullerene (C60) through controlling the environmental temperature and the incident velocity of C60. The self-healing probability depends on the size of graphene, the velocity of fullerene (C60), and the temperature of heat baths. It is suggested that the self-healing in damaged graphene originates from thermal fluctuation. Our results can offer additional insights for further understanding self-healing mechanisms and bombardment phenomena in low dimensional materials. Additionally, controlling the bombardment between the graphene and the fullerene (C60) may also lead to some potential applications in the surface cleaning of graphene and the production of nanopore.

  2. Secondary ion emission under keV carbon cluster bombardment

    E-print Network

    Locklear, Jay Edward

    2006-10-30

    to be the product of both direct and recombination/rearrangement emission. Re-emitted projectile atoms in the form F- were found under C60F40+ bombardment. Two forms of re-emitted F- were found: One form in which F atoms retained a portion of the initial kinetic...

  3. Surface damage studies of ETFE polymer bombarded with low energy Si ions (?100 keV)

    NASA Astrophysics Data System (ADS)

    Minamisawa, Renato Amaral; De Almeida, Adelaide; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

    2007-08-01

    Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer.

  4. Chemical evolution of frozen methane by keV ion bombardment

    Microsoft Academic Search

    G. Foti; L. Calcagno; F. Z. Zhou; G. Strazzulla

    1987-01-01

    Frozen methane layers at low temperature (~10 K) have been irradiated with high energy ion beams (keV Ar+ and He+). Molecular emission of H2, CH4, C2H2, C2H4 and C2H6 has been detected as a function of ion fluence in the range 1014 ions\\/cm2. Most of the original carbon atoms are bound after ion bombardment to form a hydrogenated amorphous carbon

  5. Study of the surface activation of ETFE by low energy (keV) Si and N bombardment

    NASA Astrophysics Data System (ADS)

    Parada, M. A.; de Almeida, A.; Muntele, C.; Muntele, I.; Delalez, N.; Ila, D.

    2005-12-01

    The ethylenetetrafluoroethylene (ETFE) is a polymer formed by alternating ethylene and tetrafluoroethylene segments. It can be applied in the field of medical physics as intra venous catheters and as radiation dosimeters. The increasing application of polymeric materials in technological and scientific fields has motivated the use of surface treatments to modify the physical and chemical properties of polymer surfaces. When a material is exposed to ionizing radiation, it suffers damage leading to surface activation depending on the type, energy and intensity of the applied radiation. In order to determine the radiation damage and the surface activation mechanism ETFE films were bombarded with keV Si and N at various fluences. The bombarded film was also analyzed with optical absorption photospectrometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy showing quantitatively the chemical nature at the damage caused by the Si and N bombardment.

  6. Simulation of keV particle bombardment of covalent materials: An investigation of the yield dependence on incidence angle

    Microsoft Academic Search

    Roger Smith; Don E. Harrison; Barbara J. Garrison

    1990-01-01

    The dependence of the yield, Y, of ejected particles on the angle of incidence theta is investigated for the keV particle bombardment of Si by molecular dynamics simulations using many-body potentials to describe the atom\\/atom interactions and a Molière potential to describe the ion\\/atom interactions. Results are presented for the Si{110} and the dimer reconstructed Si{100}(2 × 1) surfaces. For

  7. Stability of Extraterrestrial Glycine under Energetic Particle Radiation Estimated from 2 keV Electron Bombardment Experiments

    NASA Astrophysics Data System (ADS)

    Maté, B.; Tanarro, I.; Escribano, R.; Moreno, M. A.; Herrero, V. J.

    2015-06-01

    The destruction of solid glycine under irradiation with 2 keV electrons has been investigated by means of IR spectroscopy. Destruction cross sections, radiolysis yields, and half-life doses were determined for samples at 20, 40, 90, and 300 K. The thickness of the irradiated samples was kept below the estimated penetration depth of the electrons. No significant differences were obtained in the experiments below 90 K, but the destruction cross section at 300 K was larger by a factor of 2. The radiolysis yields and half-life doses are in good accordance with recent MeV proton experiments, which confirms that electrons in the keV range can be used to simulate the effects of cosmic rays if the whole sample is effectively irradiated. In the low temperature experiments, electron irradiation leads to the formation of residues. IR absorptions of these residues are assigned to the presence CO2, CO, OCN?, and CN? and possibly to amide bands I to III. The protection of glycine by water ice is also studied. A water ice film of ?150 nm is found to provide efficient shielding against the bombardment of 2 keV electrons. The results of this study show also that current Monte Carlo predictions provide a good global description of electron penetration depths. The lifetimes estimated in this work for various environments ranging from the diffuse interstellar medium to the inner solar system, show that the survival of hypothetical primeval glycine from the solar nebula in present solar system bodies is not very likely.

  8. Sputtering of parent-like ions from large organic adsorbates on metals under keV ion bombardment

    NASA Astrophysics Data System (ADS)

    Delcorte, A.; Bertrand, P.

    1998-09-01

    Thin films of hydrocarbon molecules, unsaturated fatty acid and low molecular weight polystyrene deposited on different metal substrates (silver, copper and gold) were bombarded by 15 keV Ga ions and the secondary ions were mass- and energy-analysed by means of a time-of-flight secondary ion mass spectrometer. The samples were studied in order to evidence the effects of different substrates and coverages on the emission of the parent and cationised molecular ions, and to gain a better understanding of the large molecular ion emission processes. Ion beam degradation studies were realised for fundamental purposes too. In general, the kinetic energy distributions of metal-cationised molecules are broad in comparison with those of the parent ions, and of the smaller polystyrene fingerprint ions. In addition, the velocity distributions of the parent ions and of the metal-cationised molecules are similar. Parent ions of aromatic molecules are, on average, more energetic than those of aliphatic molecules. In the case of metal-cationised molecules, the three hypotheses of emission of a preformed complex, recombination in the selvedge and metastable decay of larger aggregates are critically reviewed in comparison with the experimental data. The recombination hypothesis cannot account for the whole set of observations. On the other hand, the very different evolutions of the parent ions and of the metal-cationised molecules in the degradation experiments cannot be explained solely in the frame of metastable decay reactions, although the kinetic energy measurements show that a significant fraction of the parent-like ions are produced in the vacuum. The augmentation of the secondary ion kinetic energy with increasing molecule size for triacontane monomers and dimers, and for silver-cationised polystyrene oligomers, is in disagreement with the sputtering by a single cascade atom, too. Finally, the discussion outlines the conditions that must be satisfied to model the experimental observations and proposes a view of the sputtering of these large molecular cations based on multiple collision processes and possible subsequent dissociation in the vacuum.

  9. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    SciTech Connect

    Siekhaus, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Teslich, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30keV gallium ions or 16kev cesium ions to depths much greater than the ions’ range, i.e. using steady state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U??Ga??, (UC)??Ga?? and U??Cs?, (UC)??Cs??, respectively.

  10. The temperature effect on the glycine decomposition induced by 2 keV electron bombardment in space analog conditions

    NASA Astrophysics Data System (ADS)

    Pilling, Sergio; Nair, Binu G.; Escobar, Antonio; Fraser, Helen; Mason, Nigel

    2014-03-01

    Glycine is the simplest proteinaceous amino acid that has been extensively detected in carbonaceous meteorites and was recently observed in the cometary samples returned to Earth by NASA's Stardust spacecraft. In space, such species is exposed to several radiation fields at different temperatures. In aqueous solutions, this species appears mainly as zwitterionic glycine (+NH3CH2COO-) however, in solid phase, it may be found in amorphous or crystalline forms. Here, we present an experimental study on the destruction of two zwitterionic glycine crystals ( ?- and ?-form) at two different temperatures (300 K and 14 K) by 2 keV electrons in an attempt to test the behavior and stability of this molecular species in different space environments. The samples were analyzed in situ by Fourier transform infrared spectrometry at electron fluences. The experiments were carried out under ultra-high vacuum conditions at the Molecular Physics Laboratory at the Open University at Milton Keynes, UK. The dissociation cross section of glycine is approximately 5 times higher for the 14 K samples when compared to the 300 K samples. In contrast, no significant differences emerged between the dissociation cross sections of ?- and ?-forms of glycine for fixed temperature experiments. We therefore conclude that the destruction cross section is more heavily dependent on temperature than the phase of the condensed glycine material. This may be associated with the opening of additional reaction routes in the frozen samples involving the trapped daughter species (e.g. CO2 and CO). The half-life of studied samples extrapolated to space conditions shows that glycine molecules on the surface of interstellar grains has less survivability and they are highly sensitive to ambient radiations, however, they can survive extended period of time in the solar system like environments. Survivability increases by a factor of 5 if the samples are at 300 K when compared to low temperature experiments at 14 K and is independent of the crystalline structure. In addition, this survival would increase if the molecular species were protected by several layers of other molecular species as trapped in comet mantles or embedded within regolith in asteroids/lunar surfaces. The understanding of the excitation and dissociation processes of organic compounds in space simulation is highly required to put constrains in the puzzle over the origin of life in the primitive Earth.

  11. The Fullerenes

    NASA Astrophysics Data System (ADS)

    Kroto, H. W.; Walton, D. R. M.

    1993-09-01

    1. The evolution of the football structure for the C60 molecule: a retrospective E. Osawa; 2. Dreams in a charcoal fire: predictions about giant fullerenes and graphite nanotubes D. E. H. Jones; 3. On the formation of the fullerenes R. F. Curl; 4. Production and discovery of fullerites: new forms of crystalline carbon W. Kratschmer and D. R. Huffman; 5. Systematics of fullerenes and related clusters P. W. Fowler; 6. The fullerenes: powerful carbon-based electron acceptors R. C. Haddon; 7. The carbon-bearing material in the outflows from luminous carbon-rich stars M. Jura; 8. Elemental carbon as interstellar dust C. T. Pillinger; 9. The pattern of additions to fullerenes R. Taylor; 10. Polyynes and the formation of fullerenes H. W. Kroto and D. R. M. Walton; 11. Hypothetical graphite structures with negative gaussian curvature A. L. Mackay and H. Terrones; 12. Fullerenes as an example of basic research in industry E. Wasserman; 13. Deltahedral views of fullerene polymorphism D. L. D. Caspar; 14. Geodesic domes and fullerenes.

  12. The Stability of Cosmic Fullerenes and Fullerenic Aggregates

    NASA Astrophysics Data System (ADS)

    Micelotta, E. R.; Cami, J.; Peeters, E.; Zettergren, H.; Schmidt, H. T.; Cederquist, H.; Jones, A. P.; Tielens, A. G. G. M.

    2014-02-01

    Establishing the stability of cosmic fullerenes and fullerenic aggregates is extremely relevant for a variety of reasons. For instance, the emission features of C60 and C70 fall in the same spectral region as the Un-identified InfraRed (UIR) bands, which they could contribute to. To be able to contribute to the UIR emission, however, fullerenes must be able to survive long enough against the destruction mechanisms operating in the interstellar medium. In this study we focus on the effects of collisional processing, i.e., the bombardment by energetic ions and electrons. A recent experimental/theoretical study has shown that ion collisions with C60 clusters result in the dissociation of the cluster with the simultaneous formation of covalent fullerene dimers, which could play a role as DIBs carriers. We present here our first results about the collisional processing of C60 molecules and clusters by H, He and C ions in interstellar shocks. We have adapted the models that have previously been developed to successfully treat the collisional processing of PAHs in space. The nature of the interaction and the similarities between PAHs and fullerenes make this approach appropriate. In addition, our study shows that the formation of covalent dimers following ion collisions with C60 clusters is compatible with the astrophysical conditions under consideration.

  13. Fullerene materials

    SciTech Connect

    Malhotra, R.; Ruoff, R.S.; Lorents, D.C. [SRI International, Menlo Park, CA (United States). Molecular Physics Lab.

    1995-04-01

    Fullerenes are all-carbon cage molecules. The most celebrated fullerene is the soccer-ball shaped C{sub 60}, which is composed of twenty hexagons and twelve pentagons. Because its structure is reminiscent of the geodesic domes of architect R. Buckminster Fuller, C{sub 60} is called buckminsterfullerene, and all the materials in the family are designated fullerenes. Huffman and Kraetschmer`s discovery unleashed activity around the world as scientists explored production methods, properties, and potential uses of fullerenes. Within a short period, methods for their production in electric arcs, plasmas, and flames were discovered, and several companies began selling fullerenes to the research market. What is remarkable is that in all these methods, carbon atoms assemble themselves into cage structures. The capability for self-assembly points to some inherent stability of these structures that allows their formation. The unusual structure naturally leads to unusual properties. Among them are ready solubility in solvents and a relatively high vapor pressure for a pure carbon material. The young fullerene field has already produced a surprising array of structures for the development of carbon-base materials having completely new and different properties from any that were previously possible.

  14. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1993-01-01

    A method of forming synthetic diamond on a substrate is disclosed. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond thickness on the substrate.

  15. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic diamond on a substrate. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond film thickness on the substrate.

  16. Rice transformation: bombardment

    Microsoft Academic Search

    Paul Christou

    1997-01-01

    Bombardment-based methodology is responsible for the effective genetic manipulation of major cereals including rice. Many groups reported significant advances on various aspects of rice molecular biology and genetic engineering using procedures based on bombardment technology. Molecular and genetic characterization of large numbers of these plants (more than 500 independent transgenic plants) provided information on structure, expression and stability of integrated

  17. Fullerenes in Allende Meteorite

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bada, J. L.; Winans, R. E.; Bunch, T. E.

    1994-01-01

    The detection of fullerenes in deposits from meteor impacts has led to renewed interest in the possibility that fullerenes are present in meteorites. Although fullerenes have not previously been detected in the Murchison and Allende meteorites, the Allende meteorite is known to contain several well-ordered graphite particles which are remarkably similar in size and appearance to the fullerene-related structures carbon onions and nanotubes. We report that fullerenes are in fact present in trace amounts in the Allende meteorite. In addition to fullerenes, we detected many polycyclic aromatic hydrocarbons (PAHs) in the Allende meteorite, consistent with previous reports. In particular, we detected benzofluoranthene and corannulene (C20H10), five-membered ring structures which have been proposed as precursors to the formation of fullerene synthesis, perhaps within circumstellar envelopes or other sites in the interstellar medium.

  18. Coalescence reactions of fullerenes

    NASA Astrophysics Data System (ADS)

    Yeretzian, Chahan; Hansen, Klavs; Diederich, François; Whetten, Robert L.

    1993-03-01

    This article reviews recent work in Los Angeles on elementary processes in fullerene vapors. The production of fullerene molecules typically involves extreme high-temperature conditions and processes which are poorly understood at date [1 3]. Once generated, these molecules may represent the most stable molecules known [4,5]. In a recent work [C. Yeretzian et al., Nature 359, 44 (1992)] we presented clear evidence for coalescence reactions between fullerene molecules. Mass spectrometric measurements on hot, dense vapors of small fullerenes (C60 and C70) reveal the formation of stable higher fullerenes which are multiples of the initial masses. These processes are shown to occur in the gas-phase rather than in the solid film and their dependences on laser fluence and He-gas pressure are investigated. Three distinct reactions are proposed—coalescence, emission and capture—to account for the observed distributions at higher fullerene sizes. Specifically, the heat of coalescence is released through emission of small, even-numbered fragments which, in a very dense vapor, are efficiently captured by other coalesced fullerenes. These findings have implications for the long-time stability of the fullerene vapor, and for the mechanism of fullerene formation and growth, and may open new ways to the synthesis of selected higher fullerenes and encapsulation compounds.

  19. Combustion method for producing fullerenes

    DOEpatents

    Howard, J.B.; McKinnon, J.T.

    1993-12-28

    A method for synthesizing fullerenes in flames is provided. Fullerenes are prepared by burning carbon-containing compounds in a flame and collecting the condensable. The condensable contain the desired fullerenes. Fullerene yields can be optimized and fullerene composition can be selectively varied. Fullerene yields and compositions are determined by selectively controlling flame conditions and parameters such as C/O ratio, pressure, temperature, residence time, diluent concentration and gas velocity. 4 figures.

  20. Combustion synthesis of fullerenes and fullerenic nanostructures

    E-print Network

    Goel, Anish

    2002-01-01

    Fullerenes are molecules comprised entirely of sp²-bonded carbon atoms arranged in pentagonal and hexagonal rings to form a hollow, closed-cage structure. Buckyballs, a subset which contains C?? and C??, are single-shell ...

  1. Extraterrestrial Helium Trapped in Fullerenes in the Sudbury Impact Structure

    Microsoft Academic Search

    Luann Becker; Robert J. Poreda; Jeffrey L. Bada

    1996-01-01

    Fullerenes (C60 and C70) in the Sudbury impact structure contain trapped helium with a ^3He\\/^4He ratio of 5.5 x 10-4 to 5.9 x 10-4. The ^3He\\/^4He ratio exceeds the accepted solar wind value by 20 to 30 percent and is higher by an order of magnitude than the maximum reported mantle value. Terrestrial nuclear reactions or cosmic-ray bombardment are not

  2. Cluster formation under bombardment with polyatomic projectiles R. Heinrich, A. Wucher *

    E-print Network

    Wucher, Andreas

    -sputtering of a polycrystalline silver surface under bombardment with 8-keV atomic silver ions and polyatomic silver cluster ionsCluster formation under bombardment with polyatomic projectiles R. Heinrich, A. Wucher * Institute on the detection of neutral atoms and clusters ejected from the surface. The primary ions are generated

  3. Secondary ion emission under keV carbon cluster bombardment 

    E-print Network

    Locklear, Jay Edward

    2006-10-30

    . It is well documented that secondary ion emission is enhanced using cluster projectiles compared to atomic projectiles. Previous studies of enhanced secondary ion yields with cluster projectiles have led to the present study dealing with the scope of C60 as a...

  4. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic hydrogen defect free diamond or diamond like films on a substrate. The method involves providing vapor containing fullerene molecules with or without an inert gas, providing a device to impart energy to the fullerene molecules, fragmenting at least in part some of the fullerene molecules in the vapor or energizing the molecules to incipient fragmentation, ionizing the fullerene molecules, impinging ionized fullerene molecules on the substrate to assist in causing fullerene fragmentation to obtain a thickness of diamond on the substrate.

  5. Conversion of fullerenes to diamonds

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1995-01-01

    A method of forming synthetic diamond or diamond-like films on a substrate surface. The method involves the steps of providing a vapor selected from the group of fullerene molecules or an inert gas/fullerene molecule mixture, providing energy to the fullerene molecules consisting of carbon-carbon bonds, the energized fullerene molecules breaking down to form fragments of fullerene molecules including C.sub.2 molecules and depositing the energized fullerene molecules with C.sub.2 fragments onto the substrate with farther fragmentation occurring and forming a thickness of diamond or diamond-like films on the substrate surface.

  6. Combustion energy of fullerene soot

    SciTech Connect

    Man, Naoki; Nagano, Yatsuhisa; Kiyobayashi, Tetsu; Sakiyama, Minoru (Osaka Univ., Toyonaka (Japan))

    1995-02-23

    The standard energy of combustion of fullerene soot generated in arc discharge was determined to be [minus]36.0 [+-] 0.5 kJ g[sup [minus]1] by oxygen-bomb combustion calorimetry. The value was much closer to those of C[sub 60] and C[sub 70] than that of graphite. This result provides an energetic reason for the remarkable yield of fullerenes in arc discharge and supports the mechanism of fullerene formation, where fullerenes are the lowest energy products. Fullerene onion formation is interpreted in terms of energy relaxation of the fullerene soot. 20 refs., 1 tab.

  7. Fullerenes formation in flames

    NASA Technical Reports Server (NTRS)

    Howard, Jack B.

    1993-01-01

    Fullerenes are composed of carbon atoms arranged in approximately spherical or ellipsoidal cages resembling the geodesic domes designed by Buckminster Fuller, after whom the molecules were named. The approximately spherical fullerene, which resembles a soccer ball and contains sixty atoms (C60), is called buckminsterfullerene. The fullerene containing seventy carbon atoms (C70) is approximately ellipsoidal, similar to a rugby ball. Fullerenes were first detected in 1985, in carbon vapor produced by laser evaporation of graphite. The closed shell structure, which has no edge atoms vulnerable to reaction, was proposed to explain the observed high stability of certain carbon clusters relative to that of others at high temperatures and in the presence of an oxidizing gas.

  8. Photodynamic therapy with fullerenes†

    PubMed Central

    Mroz, Pawel; Tegos, George P.; Gali, Hariprasad; Wharton, Tim; Sarna, Tadeusz; Hamblin, Michael R.

    2010-01-01

    Fullerenes are a class of closed-cage nanomaterials made exclusively from carbon atoms. A great deal of attention has been focused on developing medical uses of these unique molecules especially when they are derivatized with functional groups to make them soluble and therefore able to interact with biological systems. Due to their extended ?-conjugation they absorb visible light, have a high triplet yield and can generate reactive oxygen species upon illumination, suggesting a possible role of fullerenes in photodynamic therapy. Depending on the functional groups introduced into the molecule, fullerenes can effectively photoinactivate either or both pathogenic microbial cells and malignant cancer cells. The mechanism appears to involve superoxide anion as well as singlet oxygen, and under the right conditions fullerenes may have advantages over clinically applied photosensitizers for mediating photodynamic therapy of certain diseases. PMID:17973044

  9. Electron bombardment CCD camera

    Microsoft Academic Search

    Tadashi Maruno; Masahiko Shirai; Fumio Iwase; Naotaka Hakamata

    1998-01-01

    Two kinds of electron bombardment CCD (EB-CCD) camera are newly developed, employing an EB-CCD sensor made by Hamamatsu Photonics. The slow scan cooled CCD camera installs the full frame transfer type EB-CCD sensor with 512 X 512 pixel format and standard video rate camera installs the frame transfer type EB-CCD sensor with 658 X 490 pixel format. For slow scan

  10. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W. [Naval Research Lab., Washington, DC (United States)

    1996-04-05

    Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than a decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.

  11. Blistering and deuterium trapping induced by D + ion bombardment ES metal alloys

    NASA Astrophysics Data System (ADS)

    Navinšek, B.; Peternel, M.; Žabkar, A.; Erents, S. K.

    1980-10-01

    Four candidates for the first wall material in fusion devices, namely Inconel 600, Nimonic alloy PE 16, Hastelloy B, and stainless steel 316 L, have been studied from the point of view of deuterium trapping and blister formation. The measurements of deuterium re-emission during 36 keV D + bombardment at room temperature, and 33 keV D + bombardment at 77 K have been made. The re-emission from Inconel 600 has been observed to be higher than that from PE 16 at 300 K. All materials behave similarly at 77 K. Blistering was studied in detail for Inconel 600 and PE 16 alloy following 77 K bombardments. No surface changes were observed due to the bombardment at room temperature.

  12. Decomposition of indium nitride by ion bombardment with the formation of indium tungstate

    Microsoft Academic Search

    M. S. Wong; F. G. Karioris; L. Cartz

    1985-01-01

    Bombardment by Kr (3 MeV) ions of a fine powder of InN on a W substrate results in decomposition to indium and to the formation of indium tungstate In 0.4WO3 or InW3O9.By contrast, bombardments at 150 keV results in the decomposition but no further reaction. The formation of Indium tungstate is considered an ion mixing reaction induced by the 3

  13. Temperature dependent segregation of metals at Si–SiO2 interfaces during oxygen ion bombardment

    Microsoft Academic Search

    J. S. Williams; K. T. Short; A. E. White

    1997-01-01

    Rutherford backscattering and channeling techniques have been used to study temperature-dependent segregation of Cu, Au, and Pd at Si–SiO2 interfaces during high dose 15 keV O+ bombardment of Si. Results illustrate a strong tendency for metals to be retained in an amorphous Si layer adjacent to the continuous SiO2 layer formed by O+ bombardment of Si. The magnitude of segregation

  14. Electroluminescence in fullerene crystals

    Microsoft Academic Search

    A. T. Werner; Hugh J. Byrne; D. O'Brien; Siegmar Roth

    1994-01-01

    The observation of a broadband electroluminescent emission from fullerene crystals, with a spectral distribution comparable to that of the photoluminescence at high excitation densities is described. The emission intensity is highly nonlinearly dependent on the current. The response of the crystal to the application of an alternating current is investigated to determine the dynamic parameters of the emission process. In

  15. Geological occurrence of fullerenes

    SciTech Connect

    Buseck, P.R.; Tsipursky, S.J.; Wang, S. (Arizona State Univ., Tempe, AZ (United States)); Hettich, R. (Oak Ridge National Lab., TN (United States))

    1992-01-01

    Using HRTEM imaging, the authors found C[sub 60] and C[sub 70] fullerenes in shungite, a Precambrian carbon-rich rock from Karelia, Russia. Compositionally, shungite represents coals of the meta-anthracite rank, characterized by low ash and sulfur contents, low volatile yields, and high carbon contents. The shungite occurs within metamorphosed sediments. The overlying rocks consist of gray dolomitized sandstones and poorly sorted silts and clays; the underlying rocks are not exposed. The shungite consists of masses containing up to 99% carbon. Diabase is interstratified with shungite-bearing rocks, and the shungite concentration increases with proximity to the diabase. Their sample comes from inclusions in the diabase. In the HRTEM images the fullerenes appear round (presumably roughly spherical in three dimensions), with white rims and black centers, almost identical to images of synthetic C[sub 60] molecules. Following the HRTEM observations, the fullerene identities were confirmed, first by time-of-flight mass spectrometry and then by more precise laser ablation, laser desorption, and thermal desorption ionization plus Fourier transform (FT) mass spectrometry. These measurements verified that the fullerenes were not generated by the laser ionization event. HRTEM images show that locally they occur in ordered arrays that resemble crystals of synthetic C[sub 60]. FT mass spectra show that the C-13/C-12 isotopic ratios for C[sub 60] and C[sub 70] fall within the normal range of terrestrial isotopic values.

  16. Antigenicity of fullerenes: Antibodies specific for fullerenes and their characteristics

    PubMed Central

    Chen, B.-X.; Wilson, S. R.; Das, M.; Coughlin, D. J.; Erlanger, B. F.

    1998-01-01

    The recent interest in using Buckminsterfullerene (fullerene) derivatives in biological systems raises the possibility of their assay by immunological procedures. This, in turn, leads to the question of the ability of these unprecedented polygonal structures, made up solely of carbon atoms, to induce the production of specific antibodies. Immunization of mice with a C60 fullerene derivative conjugated to bovine thyroglobulin yielded a population of fullerene-specific antibodies of the IgG isotype, showing that the immune repertoire was diverse enough to recognize and process fullerenes as protein conjugates. The population of antibodies included a subpopulation that crossreacted with a C70 fullerene as determined by immune precipitation and ELISA procedures. These assays were made possible by the synthesis of water-soluble fullerene derivatives, including bovine and rabbit serum albumin conjugates and derivatives of trilysine and pentalysine, all of which were characterized as to the extent of substitution and their UV-Vis spectra. Possible interactions of fullerenes with the combining sites of IgG are discussed based on the physical chemistry of fullerenes and previously described protein-fullerene interactions. They remain to be confirmed by the isolation of mAbs for x-ray crystallographic studies. PMID:9724786

  17. Fullerenes with metals inside

    SciTech Connect

    Yan Chai; Ting Guo; Chagming Jin; Haufler, R.E.; Chibante, L.P.F.; Fure, J.; Lihong Wang; Alford, J.M.; Smalley, R.E. (Rice Univ., Houston, TX (United States))

    1991-10-03

    Fullerenes with a single lanthanum atom trapped on the inside of the carbon cage were produced by laser vaporization of a lanthanum oxide/graphite composite rod in a flow of argon gas at 1,200 C. When sublimed wit C{sub 60} and C{sub 70}, they formed an air-stable film containing principally LaC{sub 60}, LaC{sub 70}, LaC{sub 74}, and LaC{sub 82}. When dissolved in toluene and exposed to air, LaC{sub 82} was found to be uniquely stable. Evidence was also obtained for coalescence reactions between these fullerenes at high temperatures to form larger cages with as many as three lanthanum atoms inside. Indications have also been obtained for the successful production of KC{sub 60}, C{sub 59}B, and KC{sub 59}B where the boron has substituted for a carbon in the soccerball cage. The use of the {at} symbol is advocated for specifying such complex fullerenes as (K{at}C{sub 59}B).

  18. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Liu, Shengzhong (Woodridge, IL); Krauss, Alan R. (Naperville, IL); Pan, Xianzheng (Woodridge, IL)

    1997-01-01

    A method and system for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate.

  19. Chiral fullerenes from asymmetric catalysis.

    PubMed

    Maroto, Enrique E; Izquierdo, Marta; Reboredo, Silvia; Marco-Martínez, Juan; Filippone, Salvatore; Martín, Nazario

    2014-08-19

    Fullerenes are among the most studied molecules during the last three decades, and therefore, a huge number of chemical reactions have been tested on these new carbon allotropes. However, the aim of most of the reactions carried out on fullerenes has been to afford chemically modified fullerenes that are soluble in organic solvents or even water in the search for different mechanical, optical, or electronic properties. Therefore, although a lot of effort has been devoted to the chemical functionalization of these molecular allotropes of carbon, important aspects in the chemistry of fullerenes have not been properly addressed. In particular, the synthesis of chiral fullerenes at will in an efficient manner using asymmetric catalysis has not been previously addressed in fullerene science. Thus, despite the fact that the chirality of fullerenes has always been considered a fundamental issue, the lack of a general stereoselective synthetic methodology has restricted the use of enantiopure fullerene derivatives, which have usually been obtained only after highly expensive HPLC isolation on specific chiral columns or prepared from a pool of chiral starting materials. In this Account, we describe the first stereodivergent catalytic enantioselective syntheses in fullerene science, which have allowed the highly efficient synthesis of enantiomerically pure derivatives with total control of the stereochemical result using metallic catalysts and/or organocatalysts under very mild conditions. Density functional theory calculations strongly support the experimental findings for the assignment of the absolute configuration of the new stereocenters, which has also been ascertained by application of the sector rule and single-crystal X-ray diffraction. The use of the curved double bond of fullerene cages as a two-?-electron component in a variety of stereoselective cycloaddition reactions represents a challenging goal considering that, in contrast to most of the substituted olefins used in these reactions, pristine fullerene is a noncoordinating dipolarophile. The aforementioned features make the study of stereoselective 1,3-dipolar cycloadditions onto fullerenes a unique scenario to shed light onto important mechanistic aspects. On the other hand, the availability of achiral starting materials as well as the use of nonexpensive asymmetric catalysts should provide access to chiral fullerenes and their further application in a variety of different fields. In this regard, in addition to biomedical applications, chiral fullerenes are of interest in less-studied areas such as materials science, organic electronics, and nanoscience, where control of the order and morphology at the nanometer scale are critical issues for achieving better device efficiencies. PMID:25080165

  20. Temperature measurement of microcrystals heated by electron bombardment: W tips from 2800K to 3650K

    Microsoft Academic Search

    Vu Thien Binh; P. Heyde; M. Drechsler; R. Uzan

    1981-01-01

    For controlled heating of metal microcrystals up to the melting point, the end of the field emitter tips are bombarded by an electron beam (8 keV, 400 mu A, 200 mu m beam diameter). To measure local temperatures on small areas down to 2 mu m diameter a special one-wavelength micropyrometer was built. Using an optical microscope, an image of

  1. Dynamics Displayed by Energetic C60 Bombardment of Metal Overlayers on an Organic Substrate

    E-print Network

    Zbigniew, Postawa

    : Cluster bombardments of 15 keV C60 on metal-organic interfaces composed of silver atoms and octatetraene are sputtered predominantly by a rapid jetlike motion and the implantation of metal atoms and clusters in the underlying organic solid. Both of these processes negatively affect the information depth for cluster

  2. Magnetization of electron-bombarded iron--cobalt films

    SciTech Connect

    Chebotkevich, L.A.; Lifshits, V.G.; Nachinov, V.A.; Vorob'ev, Y.D.; Veter, V.V.; Ulmanis, U.A.

    1982-09-01

    Chromium-doped iron--cobalt films are bombarded by electrons with energies of 75 keV and 3.8 MeV. The dose and concentration dependence of the relative magnetization are investigated. Estimates are made for the contributions to the change in the magnetization and coercive field due to the following radiation effects: the change in the chemical composition, amorphization, the change in the thickness, and the formation of radiation defects. It is shown that the addition of chromium to Fe/sub 0.6/Co/sub 0.4/ films leads to a stronger decrease in the magnetization.

  3. Closed network growth of fullerenes.

    PubMed

    Dunk, Paul W; Kaiser, Nathan K; Hendrickson, Christopher L; Quinn, John P; Ewels, Christopher P; Nakanishi, Yusuke; Sasaki, Yuki; Shinohara, Hisanori; Marshall, Alan G; Kroto, Harold W

    2012-01-01

    Tremendous advances in nanoscience have been made since the discovery of the fullerenes; however, the formation of these carbon-caged nanomaterials still remains a mystery. Here we reveal that fullerenes self-assemble through a closed network growth mechanism by incorporation of atomic carbon and C(2). The growth processes have been elucidated through experiments that probe direct growth of fullerenes upon exposure to carbon vapour, analysed by state-of-the-art Fourier transform ion cyclotron resonance mass spectrometry. Our results shed new light on the fundamental processes that govern self-assembly of carbon networks, and the processes that we reveal in this study of fullerene growth are likely be involved in the formation of other carbon nanostructures from carbon vapour, such as nanotubes and graphene. Further, the results should be of importance for illuminating astrophysical processes near carbon stars or supernovae that result in C(60) formation throughout the Universe. PMID:22617295

  4. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    NASA Astrophysics Data System (ADS)

    Yu, L. D.; Sangwijit, K.; Prakrajang, K.; Phanchaisri, B.; Thongkumkoon, P.; Thopan, P.; Singkarat, S.; Anuntalabhochai, S.

    2014-05-01

    As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10-20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

  5. Metal ion bombardment of onion skin cell wall

    SciTech Connect

    Sangyuenyongpipat, S.; Vilaithong, T.; Yu, L.D.; Verdaguer, A.; Ratera, I.; Ogletree, D.F.; Monteiro, O.R.; Brown, I.G.

    2004-05-10

    Ion bombardment of living cellular material is a novel subfield of ion beam surface modification that is receiving growing attention from the ion beam and biological communities. Although it has been demonstrated that the technique is sound, in that an adequate fraction of the living cells can survive both the vacuum environment and energetic ion bombardment, there remains much uncertainty about the process details. Here we report on our observations of onion skin cells that were subjected to ion implantation, and propose some possible physical models that tend to support the experimental results. The ion beams used were metallic (Mg, Ti, Fe, Ni, Cu), mean ion energy was typically 30keV, and the implantation fluence was in the range 1014 1016 ions/cm2. The cells were viewed using Atomic Force Microscopy, revealing the formation of microcrater-like structures due to ion bombardment. The implantation depth profile was measured with Rutherford backscattering spectrometry and compared to the results of the TRIM, T-DYN and PROFILE computer codes.

  6. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, D.M.; Liu, S.; Krauss, A.R.; Pan, X.

    1997-04-15

    A method and system are disclosed for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate. 10 figs.

  7. Production Of Fullerenic Soot In Flames

    DOEpatents

    Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

    2000-12-19

    A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

  8. Production of fullerenic nanostructures in flames

    DOEpatents

    Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

    1999-01-01

    A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

  9. Effects of low and high energy ion bombardment on ETFE polymer

    NASA Astrophysics Data System (ADS)

    Minamisawa, R. A.; De Almeida, A.; Abidzina, V.; Parada, M. A.; Muntele, I.; Ila, D.

    2007-04-01

    The polymer ethylenetetrafluoroethylene (ETFE) is used as anti-adherent coatings for food packages and radiation dosimeters. In this work, we compare the damage induced in ETFE bombarded with 100 keV Si ions with that induced by 1 MeV proton bombardment. The damage depends on the type, energy and intensity of the irradiation. Irradiated films were analyzed with optical absorption photospectrometry, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy to determine the chemical nature of the structural changes caused by ion irradiation. Computer simulations were performed to evaluate the radiation damage.

  10. Electrochemically formed fullerene-based polymeric films

    Microsoft Academic Search

    Krzysztof Winkler; Alan L. Balch; W?odzimierz Kutner

    2006-01-01

    The recent results of investigations involving the electrochemical formation of polymers containing fullerenes and studies of their properties and applications are critically reviewed. From a structural point of view, these polymers can be divided into four main categories including (1) polymers with fullerenes physically incorporated into the foreign polymeric network without forming covalent bonds, (2) fullerene homopolymers formed via [2+2

  11. Ion bombardment in RF photoguns

    SciTech Connect

    Pozdeyev,E.; Kayran, D.; Litvinenko, V. N.

    2009-05-04

    A linac-ring eRHIC design requires a high-intensity CW source of polarized electrons. An SRF gun is viable option that can deliver the required beam. Numerical simulations presented elsewhere have shown that ion bombardment can occur in an RF gun, possibly limiting lifetime of a NEA GaAs cathode. In this paper, we analytically solve the equations of motion of ions in an RF gun using the ponderomotive potential of the Rf field. We apply the method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of ions produced in the gun can reach the cathode if no special precautions are taken. Also, the paper discusses possible mitigation techniques that can reduce the rate of ion bombardment.

  12. Ion bombardment in RF guns

    SciTech Connect

    Pozdeyev, E.; Kayran, D.; Litvinenko, V. N. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

    2009-08-04

    We use the ponderomotive potential of the RF field to study the motion of ions in an RF gun. We apply this method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of the ions produced in the gun can reach the cathode if no special precautions are taken. Also, we propose simple mitigation techniques that can reduce the rate of ion bombardment.

  13. Cereal transformation through particle bombardment

    NASA Technical Reports Server (NTRS)

    Casas, A. M.; Kononowicz, A. K.; Bressan, R. A.; Hasegawa, P. M.; Mitchell, C. A. (Principal Investigator)

    1995-01-01

    The review focuses on experiments that lead to stable transformation in cereals using microprojectile bombardment. The discussion of biological factors that affect transformation examines target tissues and vector systems for gene transfer. The vector systems include reporter genes, selectable markers, genes of agronomic interest, and vector constructions. Other topics include physical parameters that affect DNA delivery, selection of stably transformed cells and plant regeneration, and analysis of gene expression and transmission to the progeny.

  14. Fullerene materials: Synthesis and applications

    NASA Astrophysics Data System (ADS)

    Cassell, Alan Mitchell

    Chapter 1 describes the purification of gram quantities of Csb{70} using activated charcoal flash chromatography columns. A detailed procedure on the use of these columns as well as the analysis of the purified material is given. Chapter 2 describes the production and analysis of metal-containing fullerene soots produced by plasma arc discharge. A method for dispersing nanometer-sized metal particles in porous graphite rods is presented. The metal/graphite rods are then consumed in an arc discharge reactor to form the metal-containing fullerene soots. Transmission electron microscopy and powder X-ray diffraction analysis are used to characterize the soots. Chapter 3 describes the complexation of DNA with a fullerene ammonium salt. The fullerene ammonium salt/DNA complex is easily imagable using transmission electron microscopy. The formation of these DNA complexes, as well as the preparation for imaging is discussed. Also described is the preparation of a ammonium salt derivative of ferrocene which is complexed with DNA. Chapter 4 describes the self-assembly of fullerene ammonium salts. The salts assemble into vesicle and tubule type structures. Transmission electron microscopy, powder X-ray diffraction, and energy dispersive X-ray analysis is used to investigate the structures.

  15. Superconductivity in doped fullerenes

    SciTech Connect

    Hebard, A.F. (AT T Bell Labs., Murray Hill, NJ (United States))

    1992-11-01

    While there is not complete agreement on the microscopic mechanism of superconductivity in alkali-metal-doped C[sub 60], further research may well lead to the production of analogous materials that lose resistance at even higher temperatures. Carbon 60 is a fascinating and arrestingly beautiful molecule. With 12 pentagonal and 20 hexagonal faces symmetrically arrayed in a soccer-ball-like structure that belongs to the icosahedral point group, I[sub h], its high symmetry alone invites special attention. The publication in September 1990 of a simple technique for manufacturing and concentrating macroscopic amounts of this new form of carbon announced to the scientific community that enabling technology had arrived. Macroscopic amounts of C[sub 60] (and the higher fullerenes, such as C[sub 70] and C[sub 84]) can now be made with an apparatus as simple as an arc furnace powered with an arc welding supply. Accordingly, chemists, physicists and materials scientists have joined forces in an explosion of effort to explore the properties of this unusual molecular building block. 23 refs., 6 figs.

  16. Sputtering of cryogenic films of hydrogen by keV ions: Thickness dependence and surface morphology.

    E-print Network

    . Jørgen Schou1 and Noel Hilleret2 The solid hydrogen isotopes are the most volatile solids which exist in equilibrium with vacuum. For bombardment with 10 keV hydrogen ions the sputtering yield of these solids ranges at a temperature of 2-3 K, and the thickness ranged from a fraction of a monolayer up to several thousands

  17. 42nd Bombardment Squadron (Heavy). History of the 42nd Bombardment Squadron (Heavy) 1940 - 1944

    E-print Network

    United States Army Air Corps; United States Army Air Corps

    1946-01-01

    History of the 42d Bombardment Squadron (H). 1940 ? 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical Association..., IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the History of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force...

  18. 42nd Bombardment Squadron (Heavy). History of the 42nd Bombardment Squadron (Heavy) 1940 - 1944 

    E-print Network

    United States Army Air Corps; United States Army Air Corps

    1946-01-01

    History of the 42d Bombardment Squadron (H). 1940 ? 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical Association..., IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the History of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force...

  19. ELECTRON BOMBARDMENT OF BIOLOGICAL MATERIALS

    PubMed Central

    Whelden, Roy M.; Buchwald, Charles E.; Cooper, Franklin S.; Haskins, Caryl P.

    1940-01-01

    A study has been undertaken of the rate of inactivation of spores of the ascomycete fungus Aspergillus niger when bombarded in vacuum, with homogeneous beams of cathode rays of energies from 4 to 15 electron kv. and current densities of 1 x 10–7 to 3 x 10–6 amperes per square cm. These velocities and densities are in the range of those of showers of secondary electrons produced in biological materials irradiated with moderately soft x-rays, and so may be made to serve as quantitative indicators of the mechanics of x-ray action. Four qualitative effects are described. PMID:19873162

  20. Surface Erosion of Metal Molybdenum Bombarded with Energetic Hydrogen or Helium Ions

    Microsoft Academic Search

    Shuichi Okuda; Hideo Akimune

    1979-01-01

    A study has been made on the surface of polycrystalline molybdenum bombarded with H2+ or He+ at energies of 15-40 keV at dose rates of 0.6-2.1 mA\\/cm2 to doses below 38 C\\/cm2 at temperatures of 250-830°C. The results show that there is no qualitative difference between the erosion properties of H2+ and He+, but that the erosion yields of He+

  1. Secondary ion and electron yield measurements for surfaces bombarded with large molecular ions

    Microsoft Academic Search

    G. Westmacott; W. Ens; K. G. Standing

    1996-01-01

    Secondary-ion and secondary-electron emission yields from surfaces bombarded wish large molecular ions have been measured in a tandem time-of-flight mass spectrometer. The primary ions were produced by matrix-assisted laser desorption\\/ionization and ranged in mass from about 6000 to 110000 u, and in energy from 5 to 25 keV. The yields were measured for surfaces of stainless steel and CsI in

  2. Ion bombardment into inner wall surfaces of tubes and their biomedical applications

    NASA Astrophysics Data System (ADS)

    Iwaki, M.; Nakao, A.; Kaibara, M.; Sasabe, H.; Kaneko, S.; Nakajima, H.; Suzuki, Y.; Kusakabe, M.; Fujihana, T.

    1995-12-01

    A study has been made of ion bombardment into the inner wall surfaces of tubes to develop hybrid type, small diameter artificial vascular grafts. Substrates used were polystyrene with an inside diameter of 2 mm and segmented polyurethane (SPU) coated glass tube with an inside diameter of 1.5 mm. Ne-ion bombardment into inner wall surfaces of tubes was performed at an energy of 150 keV with an average fluence of 4 × 10 14 ions/cm 2 at an incident angle of about 88.3°. The surface modification of inner wall surfaces was examined by X-ray photoelectron spectroscopy, which showed the presence of amorphous carbon structures in the inner surfaces of Ne bombarded tubes. Endothelialization was performed on the Ne-bombarded SPU coated inner wall of a glass tube, although it could not be done without ion bombardment. A femoral artery has been replaced by the new artificial graft, and exposed to blood for 24 hours. The new graft demonstrated 100% patency. The development of artificial vascular grafts will be feasible by ion beam modification of inner wall surfaces of tubes.

  3. Effect of concurrent N2 ion bombardment

    E-print Network

    Zexian, Cao

    Effect of concurrent N2 ¿ and N¿ ion bombardment on the plasma-assisted deposition of carbon-cyclotron-wave resonance plasma assisted deposition of amorphous CN film, for which the variation of the film composition applied for the bombardment-assisted deposition are less than 200 eV so as to prevent the conceivable

  4. Stable transformation of papaya via microprojectile bombardment

    Microsoft Academic Search

    Maureen M. M. Fitch; Richard M. Manshardt; Dennis Gonsalves; Jerry L. Slightom; John C. Sanford

    1990-01-01

    Stable transformation of papaya (Carica papaya L.) has been achieved following DNA delivery via high velocity microprojectiles. Three types of embryogenic tissues, including immature zygotic embryos, freshly explanted hypocotyl sections, and somatic embryos derived from both, were bombarded with tungsten particles carrying chimeric NPTII and GUS genes. All tissue types were cultured prior to and following bombardment on half-strength MS

  5. Synthesis, properties and transformations of fullerene peroxides

    NASA Astrophysics Data System (ADS)

    Bulgakov, R. G.; Galimov, D. I.; Dzhemilev, U. M.

    2014-08-01

    Methods of synthesis, properties and transformations of fullerene peroxides are considered and systematized for the first time. It is shown that the chemistry of fullerene peroxides is a new approach to functionalization of fullerenes, which has been intensively developing since 2002. Methods of synthesis, mechanisms of formation and reactions of C60 and C70 alkyl peroxides with or without epoxide moieties are discussed. Transformations of fullerene peroxides affording a wide range of fullerene derivatives containing, as addends, halogen or sulfur atoms; epoxide, dioxolane, thiirane, crown ether, aziridine and dioxetane rings, as well as hydroxyl, alkoxyl and carbonyl groups, are considered. Special attention is focused on reactions constituting the basis of a new approach — so-called molecular surgery, which enables the synthesis of open-cage fullerene derivatives. It has been demonstrated that such compounds are good candidates for designing photovoltaic cells and carriers of drugs and radionuclides (for radiopharmaceuticals). The bibliography includes 130 references.

  6. Ion Bombardment Experiments Suggesting an Origin for Organic Particles in Pre-Cometary and Cometary Ices

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1997-01-01

    Simple molecules frozen as mantles of interstellar and circumstellar grains and incorporated into comets are subjected to ion bombardment in the form of cosmic rays, stellar flares, stellar winds, and ions accelerated in stellar wind shocks. The total expected dosage for the variety of situations range from 10 eV/molecule for interplanetary dust subjected to solar flares to 10(exp 6) eV/molecule for material in the T Tauri environment. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, we have bombarded frozen gases in the temperature range of 10 K to 30 K with 175 keV protons. After irradiation, removal of the ice by sublimation at an elevated temperature in vacuum reveals a fluffy residue. These experiments suggest that processes resulting in the formation of organic particles found in the coma of Comet Halley, "CHON", may have included ion bombardment. Also, the moderate energy (100 keV to 500 keV) shock accelerated ion environment of bipolar outflow of stars in the planetary nebula stage such as the Red Rectangle, could produce complex molecular species which emit the observed unidentified infrared bands at 3.3 micro-m, 6.2 micro-m, 7.7 micro-m, 8.6 micro-m, and 11.3 micro-m.

  7. C(240)-----The most Chemically Inert Fullerene?

    NASA Technical Reports Server (NTRS)

    Haddon, R. C.; Scuseria, G. E.; Smalley, R. E.

    1997-01-01

    The reactivity of the fullerenes is primarily a function of their strain, as measured by the pyramidalization angle or curvature of the conjugated carbon atoms. The development of faceting in the structure of large icosahedral fullerenes leads to a minimum in the value of the maximum fullerene pyramidalization angle that lies in the vicinity of C-240. On this basis it is argued that C-240 will be the most chemically inert fullerene. This observation explains the production of [10,10] single-walled nanotubes because a C-240 hemisphere is required for the nucleation of such tubes.

  8. Development of Advanced Alloys using Fullerenes

    NASA Technical Reports Server (NTRS)

    Sims, J.; Wasz, M.; O'Brien, J.; Callahan, D. L.; Barrera, E. V.

    1994-01-01

    Development of advanced alloys using fullerenes is currently underway to produce materials for use in the extravehicular mobility unit (EMU). These materials will be directed toward commercial usages as they are continually developed. Fullerenes (of which the most common is C(sub 60)) are lightweight, nanometer size, hollow molecules of carbon which can be dispersed in conventional alloy systems to enhance strength and reduce weight. In this research, fullerene interaction with aluminum is investigated and a fullerene-reinforced aluminum alloy is being developed for possible use on the EMU. The samples were manufactured using standard commercial approaches including powder metallurgy and casting. Alloys have been processed having 1.3, 4.0 and 8.0 volume fractions of fullerenes. It has been observed that fullerene dispersion is related to the processing approach and that they are stable for the processing conditions used in this research. Emphasis will be given to differential thermal analysis and wavelength dispersive analysis of the processed alloys. These two techniques are particularly useful in determining the condition of the fullerenes during and after processing. Some discussion will be given as to electrical properties of fullerene-reinforced materials. Although the aluminum and other advanced alloys with fullerenes are being developed for NASA and the EMU, the properties of these materials will be of interest for commercial applications where specific Dual-Use will be given.

  9. Toxicological Effects of Fullerenes on Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Schomaker, Justin; Snook, Renee; Howell, Carina

    2014-03-01

    The nematode species Caenorhabditis elegans is a useful genetic model organism due to its simplicity and the substantial molecular, genetic, and developmental knowledge about the species. In this study, this species was used to test the toxicological effects of C60 fullerene nanoparticles. In previous studies using rats, a solution of C60 fullerenes in olive oil proved to extend the life of the subjects. The purpose of this experiment was to subject C. elegans to varying concentrations of C60 fullerenes and observe their toxicological effects. Initial findings indicate a link between fullerene exposure and enlargement of the vulva as well as the formation of a small nodule at the base of the tail in some individuals. While the fullerenes are not lethally toxic in C. elegans, results will be presented that pertain to changes in life span and progeny of the nematodes exposed to varying concentrations of fullerenes as well as the mechanisms of toxicity. High magnification imaging via SEM and/or AFM will be used to characterize the fullerene nanoparticles. Testing the toxicity of fullerenes in a wide variety of organisms will lead to a more complete understanding of the effects of fullerenes on living organisms to ultimately understand their effects in humans. This work was supported by National Science Foundation grants DUE-1058829, DMR-0923047, DUE-0806660 and Lock Haven FPDC grants.

  10. Extraterrestrial Helium (He@C60) Trapped in Fullerenes in the Sudbury Impact Structure

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bada, J. L.; Poreda, R. J.; Bunch, T. E.

    1997-01-01

    Fullerenes (C60 and C70) have recently been identified in a shock-produced breccia (Onaping Formation) associated with the 1.85-Ga Sudbury Impact Crater. The presence of parts-per-million levels of fullerenes in this impact structure raises interesting questions about the processes that led to the formation of fullerenes and the potential for delivery of intact organic material to the Earth by a large bolide (e.g., asteroid or comet). Two possible scenarios for the presence of fullerenes in the Sudbury impact deposits are that (1) fullerenes are synthesized within the impact plume from the C contained in the bolide; or (2) fullerenes are already present in the bolide and survived the impact event. The correlation of C and trapped noble gas atoms in meteorites is well established. Primitive meteorites contain several trapped noble gas components that have anomalous isotopic compositions, some of which may have a presolar origin. Several C-bearing phases, including SiC, graphite, and diamond, have been recognized as carriers of trapped noble gases. It has also been suggested that fullerenes (C60 and C70) might be a carrier of noble gas components in carbonaceous chondrites. Recently, fullerenes have been detected in separate samples in the Allende meteorite. Carbon-60 is large enough to enclose the noble gases He, Ne, Ar, Kr, and Xe, but it is too small to contain diatomic gases such as N2 or triatomic gases such as CO2. Recent experimental work has demonstrated that noble gases of a specific isotopic composition can be introduced into synthetic fullerenes at high temperatures and pressures; these encapsulated gases can then be released by the breaking of one or more C bonds during step-heating under vacuum. These thermal-release patterns for He encapsulated within the C60 molecule (He@C60) are similar to the patterns for acid residues of carbonaceous chondrites, suggesting that fullerenes could be an additional carrier of trapped noble gases in acid residues of meteorites. Analysis and Results: In order to characterize the noble gas compositions of the Sudbury fullerenes, we undertook a systematic study of acid-resistant residues throughout the C-rich layer (Black member) of the Onaping Formation. Samples were demineralized and extracted using standard techniques. The Onaping extracts were analyzed using several techniques, including UV-Vis adsorption, electro spray mass spectrometry, and laser desorption (linear and reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The Sudbury fullerenes were then separated and purified using HPLC coupled with a photo diode array detector. The HPLC extracts containing the purified fullerenes were loaded into a metal tube furnace within a glove box under a N atmosphere in preparation for noble gas analyses. The 3-He and 4-He content of the fullerene extracts was measured using previously reported standard techniques . Discussion: Fullerenes (C60 and C70) in the Sudbury Impact Structure have been found to contain trapped He with a 3-He/4-He ratio greater than 5 x 10(exp -4). The 3-He/4-He ratio exceeds the accepted solar value by more than 30% and is more than 10x higher than the maximum reported mantle value. Terrestrial nuclear reactions or cosmic-my bombardment are not sufficient to generate such a high ratio. The 3-He/4-He ratios in the Sudbury fullerenes are similar to those determined for interplanetary dust particles. The greater-than-solar ratios of 3-He/4-He in the Sudbury fullerenes may indicate a presolar origin, although alternative mechanisms occurring in the ISM to explain these high ratios (e.g., spallation reactions, selective He implantation, etc.) cannot be entirely ruled out. We are currently attempting to isolate enough fullerene material to measure anomalous Ne (or Kr or Xe) contained within the C60 (e.g., the "pure" 22-Ne component) and thus determine whether the Sudbury fullerenes are indeed presolar in origin.

  11. Functionalized fullerenes in photodynamic therapy.

    PubMed

    Huang, Ying-Ying; Sharma, Sulbha K; Yin, Rui; Agrawal, Tanupriya; Chiang, Long Y; Hamblin, Michael R

    2014-09-01

    Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine CO60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT. PMID:25544837

  12. Electronic and vibrational spectroscopy of fullerene-based materials

    Microsoft Academic Search

    Mark R. Pederson; Dirk V. Porezag; Joe L. Feldman; Brian N. Davidson; Andrew A. Quong; T. Kohler; T. Frauenheim

    1995-01-01

    Recent work on the electronic and vibrational spectra of fullerenes and fullerene assembled materials is discussed. To aid in identifying the potentially useful polymeric phase of fullerene-based materials we compare various aspects of the spectra of the isolated and dimerized fullerene molecules. We discuss the core-level shifts of the spectra that are induced by polymerization and the changes in the

  13. Plasma ion source for in situ ion bombardment in a soft x-ray magnetic scattering diffractometer

    SciTech Connect

    Lengemann, Daniel; Engel, Dieter; Ehresmann, Arno [Institute of Physics, EP IV, University of Kassel, Heinrich-Plett-Str.40, 34132 Kassel (Germany) and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Str.40, 34132 Kassel (Germany)

    2012-05-15

    A new plasma ion source for in situ keV He ion bombardment of solid state samples or thin films was designed and built for ion fluences between 1 x 10{sup 12} and 1 x 10{sup 17} ions/cm{sup 2}. The system was designed to be mounted to different diffraction chambers for soft x-ray resonant magnetic scattering. Without breaking the vacuum due to He-ion bombardment, structural and magnetic modifications of the samples can be studied in situ and element specifically.

  14. Theory of Spontaneous Polarization of Endohedral Fullerenes

    NASA Astrophysics Data System (ADS)

    Clougherty, D. P.; Anderson, F. G.

    1998-04-01

    A pseudo-Jahn-Teller model describing central atom distortions is proposed for endohedral fullerenes of the form A@C60 where A is either a rare gas or a metal atom. A critical (dimensionless) coupling gc is found, below which the symmetric configuration is stable and above which inversion symmetry is broken. Vibronic parameters are given for selected endohedral fullerenes.

  15. Direct transformation of graphene to fullerene

    Microsoft Academic Search

    Andrey Chuvilin; Ute Kaiser; Elena Bichoutskaia; Nicholas A. Besley; Andrei N. Khlobystov

    2010-01-01

    Although fullerenes can be efficiently generated from graphite in high yield, the route to the formation of these symmetrical and aesthetically pleasing carbon cages from a flat graphene sheet remains a mystery. The most widely accepted mechanisms postulate that the graphene structure dissociates to very small clusters of carbon atoms such as C2, which subsequently coalesce to form fullerene cages

  16. Preparation of fullerene\\/glass composites

    Microsoft Academic Search

    Benjamin R. Mattes; Duncan W. McBranch; Jeanne M. Robinson; Aaron C. Koskelo; Steven P. Love

    1995-01-01

    Synthesis of fullerene\\/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these \\

  17. C NMR Investigations of Fullerene Black

    Microsoft Academic Search

    M. Kanowski; G. Buntkowsky; H. Werner; M. Wohlers; R. Schlögl; H.-M. Vieth; K. Lüders

    1994-01-01

    Solid-state C NMR measurements on differently treated fullerene black samples are reported. The results show that no significant amounts of C60 molecules are entrapped in fullerene black in a way that they are not accessible for conventionally used toluene extraction. The broad distribution of chemical shifts in the C MAS NMR spectra confirms the large abundance of bent carbon structures

  18. Gas storage using fullerene based adsorbents

    NASA Technical Reports Server (NTRS)

    Loutfy, Raouf O. (Inventor); Lu, Xiao-Chun (Inventor); Li, Weijiong (Inventor); Mikhael, Michael G. (Inventor)

    2000-01-01

    This invention is directed to the synthesis of high bulk density high gas absorption capacity adsorbents for gas storage applications. Specifically, this invention is concerned with novel gas absorbents with high gravimetric and volumetric gas adsorption capacities which are made from fullerene-based materials. By pressing fullerene powder into pellet form using a conventional press, then polymerizing it by subjecting the fullerene to high temperature and high inert gas pressure, the resulting fullerene-based materials have high bulk densities and high gas adsorption capacities. By pre-chemical modification or post-polymerization activation processes, the gas adsorption capacities of the fullerene-based adsorbents can be further enhanced. These materials are suitable for low pressure gas storage applications, such as oxygen storage for home oxygen therapy uses or on-board vehicle natural gas storage. They are also suitable for storing gases and vapors such as hydrogen, nitrogen, carbon dioxide, and water vapor.

  19. Fullerene–biomolecule conjugates and their biomedicinal applications

    PubMed Central

    Yang, Xinlin; Ebrahimi, Ali; Li, Jie; Cui, Quanjun

    2014-01-01

    Fullerenes are among the strongest antioxidants and are characterized as “radical sponges.” The research on biomedicinal applications of fullerenes has achieved significant progress since the landmark publication by Friedman et al in 1993. Fullerene–biomolecule conjugates have become an important area of research during the past 2 decades. By a thorough literature search, we attempt to update the information about the synthesis of different types of fullerene–biomolecule conjugates, including fullerene-containing amino acids and peptides, oligonucleotides, sugars, and esters. Moreover, we also discuss in this review recently reported data on the biological and pharmaceutical utilities of these compounds and some other fullerene derivatives of biomedical importance. While within the fullerene–biomolecule conjugates, in which fullerene may act as both an antioxidant and a carrier, specific targeting biomolecules conjugated to fullerene will undoubtedly strengthen the delivery of functional fullerenes to sites of clinical interest. PMID:24379667

  20. Study of the Ar LMM spectra by He + projectile at 1250 keV, 1500 keV and 2000 keV bombardment energies

    NASA Astrophysics Data System (ADS)

    Tóth, L.; Víkor, Gy.; Ricz, S.; Pelicon, P.; Miller, R.

    1994-03-01

    The influence of He + ion impact on the Ar LMM spectra was investigated at the ESA-21 electron spectrometer using three different ion energies. Observed line relative energies to the L 3M 2,3( 1D 2) line agree well with other results, but the relative intensities of five angular-isotropic lines deviate significantly from other measurements and theory. The angular dependence of energy shifts agrees with the quantum PCI theory of Barrachina and Macek, except for directions close to 180°, where a slight enhancement of energy shift was observed. Finally, the angular distributions of the L 2M 2,3( 1S 0), ( 1d 2) and ( 3P 0,1,2) line intensities were compared to the alignment theory of Sizov and Kabachnik.

  1. Erosion and modification of SO2 ice by ion bombardment of the surface of Io

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.; Garrett, J. W.; Boring, J. W.; Barton, L. A.; Brown, W. L.

    1984-01-01

    New measurements on the effect of slow ion bombardment of SO2 ice using Ar(+) in the 15-45 keV range are presented. Total yields for loss of SO2 are given along with the energy spectra of the ejected molecules and molecular fragments and information on the chemical changes induced by the ion bombardment. These data are used to estimate that the direct sputter ejection rate of sulfur into the Jovian plasma is of the order of 10 billion atoms/sq cm/s, that the erosion rate of fresh SO2 deposits due to sputtering is of the order of 0.001 cm/yr, and that a significant and possibly observable column density of SO3 can be produced in an SO2 front only for penetrating ion bombardment. Chemical activity occurs even in rather low-temperature SO2 ice bombardment by ions in the nuclear stopping region, and this activity is likely to increase with increasing temperature.

  2. Machine Phase Fullerene Nanotechnology: 1996

    NASA Technical Reports Server (NTRS)

    Globus, Al; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    NASA has used exotic materials for spacecraft and experimental aircraft to good effect for many decades. In spite of many advances, transportation to space still costs about $10,000 per pound. Drexler has proposed a hypothetical nanotechnology based on diamond and investigated the properties of such molecular systems. These studies and others suggest enormous potential for aerospace systems. Unfortunately, methods to realize diamonoid nanotechnology are at best highly speculative. Recent computational efforts at NASA Ames Research Center and computation and experiment elsewhere suggest that a nanotechnology of machine phase functionalized fullerenes may be synthetically relatively accessible and of great aerospace interest. Machine phase materials are (hypothetical) materials consisting entirely or in large part of microscopic machines. In a sense, most living matter fits this definition. To begin investigation of fullerene nanotechnology, we used molecular dynamics to study the properties of carbon nanotube based gears and gear/shaft configurations. Experiments on C60 and quantum calculations suggest that benzyne may react with carbon nanotubes to form gear teeth. Han has computationally demonstrated that molecular gears fashioned from (14,0) single-walled carbon nanotubes and benzyne teeth should operate well at 50-100 gigahertz. Results suggest that rotation can be converted to rotating or linear motion, and linear motion may be converted into rotation. Preliminary results suggest that these mechanical systems can be cooled by a helium atmosphere. Furthermore, Deepak has successfully simulated using helical electric fields generated by a laser to power fullerene gears once a positive and negative charge have been added to form a dipole. Even with mechanical motion, cooling, and power; creating a viable nanotechnology requires support structures, computer control, a system architecture, a variety of components, and some approach to manufacture. Additional information is contained within the original extended abstract.

  3. Fusion mechanism in fullerene-fullerene collisions -- The deciding role of giant oblate-prolate motion

    E-print Network

    Jan Handt; Ruediger Schmidt

    2015-03-09

    We provide answers to long-lasting questions in the puzzling behavior of fullerene-fullerene fusion: Why are the fusion barriers so exceptionally high and the fusion cross sections so extremely small? An ab initio nonadiabatic quantum molecular dynamics (NA-QMD) analysis of C$_{60}$+C$_{60}$ collisions reveals that the dominant excitation of an exceptionally "giant" oblate-prolate H$_g(1)$ mode plays the key role in answering both questions. From these microscopic calculations, a macroscopic collision model is derived, which reproduces the NA-QMD results. Moreover, it predicts analytically fusion barriers for different fullerene-fullerene combinations in excellent agreement with experiments.

  4. In-Situ atomic force microscopic observation of ion beam bombarded plant cell envelopes

    NASA Astrophysics Data System (ADS)

    Sangyuenyongpipat, S.; Yu, L. D.; Brown, I. G.; Seprom, C.; Vilaithong, T.

    2007-04-01

    A program in ion beam bioengineering has been established at Chiang Mai University (CMU), Thailand, and ion beam induced transfer of plasmid DNA molecules into bacterial cells ( Escherichia coli) has been demonstrated. However, a good understanding of the fundamental physical processes involved is lacking. In parallel work, onion skin cells have been bombarded with Ar + ions at energy 25 keV and fluence1-2 × 10 15 ions/cm 2, revealing the formation of microcrater-like structures on the cell wall that could serve as channels for the transfer of large macromolecules into the cell interior. An in-situ atomic force microscope (AFM) system has been designed and installed in the CMU bio-implantation facility as a tool for the observation of these microcraters during ion beam bombardment. Here we describe some of the features of the in-situ AFM and outline some of the related work.

  5. Characterizing Fullerene Nanoparticles in Aqueous Suspensions

    EPA Science Inventory

    Studies have indicated that fullerenes can form stable colloidal suspensions in water when introduced to the aqueous phase through solvent exchange, sonication, or extended mixing. The colloidal suspensions created using these techniques have effective aqueous phase concentratio...

  6. Ion bombardment and disorder in amorphous silicon

    SciTech Connect

    Sidhu, L.S.; Gaspari, F.; Zukotynski, S.

    1997-07-01

    The effect of ion bombardment during growth on the structural and optical properties of amorphous silicon are presented. Two series of films were deposited under electrically grounded and positively biased substrate conditions. The biased samples displayed lower growth rates and increased hydrogen content relative to grounded counterparts. The film structure was examined using Raman spectroscopy. The transverse optic like phonon band position was used as a parameter to characterize network order. Biased samples displayed an increased order of the amorphous network relative to grounded samples. Furthermore, biased samples exhibited a larger optical gap. These results are correlated and attributed to reduced ion bombardment effects.

  7. Inorganic nanotubes and fullerene-like nanoparticles

    Microsoft Academic Search

    R. Tenne

    2006-01-01

    Although graphite, with its anisotropic two-dimensional lattice, is the stable form of carbon under ambient conditions, on nanometre length scales it forms zero- and one-dimensional structures, namely fullerenes and nanotubes, respectively. This virtue is not limited to carbon and, in recent years, fullerene-like structures and nanotubes have been made from numerous compounds with layered two-dimensional structures. Furthermore, crystalline and polycrystalline

  8. Preparation of fullerene\\/glass composites

    Microsoft Academic Search

    B. R. Mattes; D. W. McBranch; J. M. Robinson; A. C. Koskelo; S. P. Love

    1995-01-01

    Synthesis of fullerene\\/glass composites is described. A direct method for preparing solid solutions of Cââ in silicon dioxide (SiOâ) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these ``guests`` in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results

  9. Superabsorbing Fullerenes: Spectral and Kinetic Characterization of Photoinduced Interactions in Perylenediimide-Fullerene-C60 Dyads

    E-print Network

    van Stokkum, Ivo

    light region of C60 and its derivatives impedes attaining very high efficiencies of solar energy in Perylenediimide-Fullerene-C60 Dyads Je´ro^me Baffreau, Ste´phanie Leroy-Lhez, Pie´trick Hudhomme, Michiel M state that is formed on the nanosecond time scale with a high yield. Fullerene-C60 1 still represents

  10. Symmetric nested complexes of fullerenes.

    PubMed

    Mar, Naveicy; Sansores, Luis Enrique; Muhl, Stephen; Ramos, Estrella; Salcedo, Roberto

    2015-04-01

    Large fullerenes such as C180 and C116 can be used as hosts for other molecules of the same family. Based on this idea, two complexes were designed, one in which C180 accepts a C60 molecule as a guest and the other in which C20 was placed inside C116. The behavior of these new assemblies was closer to that of a large endohedral complex rather than onion-like. There were marked differences between the systems. In the first system, there was minor interaction between the two cages but the association resulted in a more stable thermodynamic state. In the second system, there was strong electronic interchange between the cages, and the thermodynamic results suggest that such a combination might be useful for forming stable C20. PMID:25823391

  11. Electron yield of glow discharge cathode materials under helium ion bombardment

    NASA Astrophysics Data System (ADS)

    Szapiro, B.; Rocca, J. J.; Prabhuram, T.

    1988-08-01

    The secondary electron emission coefficient of materials for helium ion bombardment in the energy range 0.5-20 keV was measured for the surface conditions of cathodes in high voltage glow discharges. The materials studied are oxidized aluminum, oxidized magnesium, a molybdenum-aluminum oxide sintered composite, molybdenum, stainless steel, copper, gold, and graphite. Each sample was surface conditioned by operating it as cathode of a helium glow discharge shortly before the electron yield measurement. The results are relevant to the modeling of glow discharges and the design of cold cathode electron guns.

  12. Temperature-dependent change in the nature of glass fracture under electron bombardment

    NASA Astrophysics Data System (ADS)

    Kravchenko, A. A.

    1991-04-01

    We report the experimental discovery of a temperature-dependent change in the nature of glass fracture under low-energy (<10 keV) electron bombardment. This is shown to depend on the transition from the thermal-shock to the thermalfluctuation mechanism of fracture at the limiting temperature T1 = (Tg - 150) °C. The high-temperature cleavage fracture of K8 and TF1 glasses was studied and the threshold value of the critical power initiating cleavage fracture was determined (for the glasses studied ?thr = 50 70 W·sec·cm-2).

  13. Program fullerene: a software package for constructing and analyzing structures of regular fullerenes.

    PubMed

    Schwerdtfeger, Peter; Wirz, Lukas; Avery, James

    2013-06-30

    Fullerene (Version 4.4) is a general purpose open-source program that can generate any fullerene isomer, perform topological and graph theoretical analysis, as well as calculate a number of physical and chemical properties. The program creates symmetric planar drawings of the fullerene graph and generates accurate molecular 3D geometries by way of force-field optimization, serving as a good starting point for further quantum theoretical treatments. It includes a number of fullerene-to-fullerene transformations, such as Goldberg-Coxeter transforms, Stone-Wales transforms, Endo-Kroto, Yoshida-Fowler, and Brinkmann-Fowler vertex insertions. The program is written in standard Fortran and C++ and can easily be installed in a Linux or UNIX environment. PMID:23559399

  14. Production of high voltage by ion bombardment 

    E-print Network

    Phinney, Lucas Carter

    2003-01-01

    A beam of He+ ions was used to bombard a conductive target, allowing the target to build up a voltage. The voltage that built up on the target was measured by using a voltage divider circuit. The target was made out of niobium metal...

  15. Integrator for use in bombardment experiments.

    PubMed

    Takeda, M; Yasuda, K; Ikuta, S; Masuda, H

    1978-12-01

    A convenient integrator was developed for use in bombardment experiments with a charged particle accelerator such as a linac. In this device an irradiation dose is digitally displayed in the number of electrons per cm(2). Furthermore, a linac is controlled to deliver a preset dose by this integrator. PMID:18699049

  16. Room temperature oxidation of ion bombarded silicon

    NASA Astrophysics Data System (ADS)

    Ponpon, J. P.

    1985-10-01

    The room temperature oxidation of silicon surfaces under air ambient after ion bombardment either during dry etching or during ion implantation has been investigated. Depending on the amount of crystalline damage produced by the ion beams the oxidation kinetics was found to change from the crystalline-like to the amorphous-like behavior.

  17. Synthesis and spectroscopy studies of fullerenes and discovery of macroscopic quantities of doped fullerenes

    SciTech Connect

    Chai, Yan.

    1992-01-01

    Synthesis techniques of carbon arc and laser vaporization in the furnace for production of fullerenes have been developed. The optimum conditions for the high yields of fullerenes were tested and studied. A fullerene growth model was proposed to explain the formation of the fullerenes and the extraordinary high yield of C[sub 60]. The results of a test of this growth model was in agreement with the implications of the model. The electronic spectra of neutral C[sub 60] and C[sub 70] in the regions from 375 to 415 nm and 595 to 640 nm have been studied in a supersonically cooled molecular beam by resonant two-photon ionization spectroscopy method. Sharp spectal features were observed in both regions for C[sub 60] and in only the longer wavelength region for C[sub 70]. Neither molecule has the spectra that correspond to the diffuse interstellar bands. The first method to produce macroscopic quantities of internal metal-doped fullerenes was developed successfully and improved. Lanthanum-doped fullerenes were produced by laser vaporization of a lanthanum oxide/graphite composite rod in a flow of argon at 1200[degrees]C. Many properties of these endohedral complexes were investigated in detail. Similar results were obtained with yttrium-doped fullerenes, and double-doped endohedral fullerene complexes were first observed as a stable species in both sublimed film and toluene solution. Macroscopic quantities of other interesting metal-doped or B-doped fullerenes have been obtained and studied. Purification of these metal-doped fullerenes is in the process.

  18. Fullerenes in Meteorites and the Nature of Planetary Atmospheres

    Microsoft Academic Search

    Luann Becker; ROBERT J. POREDA; JOSEPH A. NUTH; FRANK T. FERGUSON; Feng Liang; W. Edward Billups

    We address the hypothesis that fullerenes are an important carrier phase for noble gases in carbonaceous chondrite meteorites. Unlike other proposed carbon carriers, nanodiamond, SiC, graphite and phaseQ, fullerenes are extractable in an organic solvent. It is this unique property, in fact, this may be why fullerene molecules or fullerene-related compounds were overlooked as a carrier phase of noble gases

  19. Volatile production in nonice materials on Solar System bodies with tenuous atmospheres by ion bombardment - Laboratory results

    NASA Astrophysics Data System (ADS)

    Hibbitts, C. A.; Thevuthasan, S.; Shutthanandan, V.; Orlando, T.; Hansen, G. B.; McCord, T. B.

    2003-05-01

    Volatiles, inferred to be trapped in nonice materials, have been discovered on the Jovian satellites and in IDPs [McCord et al., 1998; Hibbitts et al., 2000; Flynn et al., 2002]. In general, these types of volatiles may be produced through high-energy ion bombardment of Solar System bodies that have tenuous atmospheres, from the Moon to the Saturnian satellites and beyond. The surfaces of these bodies are continually bombarded by a combination of cosmic, solar, and planetary magnetospheric radiation including UV, keV protons and Helium nuclei, and more massive keV to MeV ions. The Moon's surface contains Fe-oxides that may release water products under bombardment by solar wind protons. Many classes of asteroids and the outer planets' satellites appear to contain clays or other OH-bearing materials that could release water-products as well under bombardment. Also, organic material, likely present on surfaces other than the Moon, may participate in bombardment reactions to form carbon monoxide or dioxide. Results from our laboratory experiments conducted at the Environmental Molecular Sciences Laboratory (EMSL) accelerator facility, Pacific Northwest National Laboratory (PNNL) show that volatiles are produced during MeV ion irradiation of these types of materials. We bombarded clays, oxyhydroxides, ilmenite, and carbon-doped samples with MeV hydrogen, deuterium, oxygen, and sulfur ions at current densities of 100 to 1000 namps ( 1E12 to 1E13 ions/cm2/sec) over several minutes. Ohmic heating and outgassing of trapped atmospheric gases was minimal at the lower flux levels. Most of the irradiation effects are non-thermal and are due to ionization and momentum transfer processes. Proton or deuteron bombardment of ilmenite produces water-related molecules that are quickly released into the vacuum chamber and detected by mass spectrometry. The bombardment of carbon-doped clays appears to produce CO. This process occurs independently of any reduction of FeO involved in micrometoroid impacts [Tsay et al., 1971].

  20. Fullerenes Can Induce Toxic Physical Changes of DNA

    Microsoft Academic Search

    Fabian Czerwinski; Lene B. Oddershede

    2008-01-01

    Fullerenes are fascinating symmetric carbon nanostructures. Nowadays, they are widely used because of their characteristic physical and chemical properties. Until now research has mainly been focused on commercial applications of fullerenes. Only a few investigations have addressed the potential biological hazards, one of which is that fullerenes are believed to alter the elastic properties of DNA upon binding. In our

  1. INFRARED STUDY OF FULLERENE PLANETARY NEBULAE

    SciTech Connect

    Garcia-Hernandez, D. A.; Acosta-Pulido, J. A.; Manchado, A. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38205 La Laguna (Spain); Villaver, E. [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Garcia-Lario, P. [Herschel Science Centre, European Space Astronomy Centre, Research and Scientific Support Department of ESA, Villafranca del Castillo, P.O. Box 78, E-28080 Madrid (Spain); Stanghellini, L.; Shaw, R. A. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Cataldo, F., E-mail: agarcia@iac.es, E-mail: amt@iac.es, E-mail: eva.villaver@uam.es, E-mail: Pedro.Garcia-Lario@sciops.esa.int, E-mail: shaw@noao.edu, E-mail: letizia@noao.edu, E-mail: franco.cataldo@fastwebnet.it [Istituto Nazionale di Astrofisica-Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy)

    2012-12-01

    We present a study of 16 planetary nebulae (PNe) where fullerenes have been detected in their Spitzer Space Telescope spectra. This large sample of objects offers a unique opportunity to test conditions of fullerene formation and survival under different metallicity environments because we are analyzing five sources in our own Galaxy, four in the Large Magellanic Cloud (LMC), and seven in the Small Magellanic Cloud (SMC). Among the 16 PNe studied, we present the first detection of C{sub 60} (and possibly also C{sub 70}) fullerenes in the PN M 1-60 as well as of the unusual {approx}6.6, 9.8, and 20 {mu}m features (attributed to possible planar C{sub 24}) in the PN K 3-54. Although selection effects in the original samples of PNe observed with Spitzer may play a potentially significant role in the statistics, we find that the detection rate of fullerenes in C-rich PNe increases with decreasing metallicity ({approx}5% in the Galaxy, {approx}20% in the LMC, and {approx}44% in the SMC) and we interpret this as a possible consequence of the limited dust processing occurring in Magellanic Cloud (MC) PNe. CLOUDY photoionization modeling matches the observed IR fluxes with central stars that display a rather narrow range in effective temperature ({approx}30,000-45,000 K), suggesting a common evolutionary status of the objects and similar fullerene formation conditions. Furthermore, the data suggest that fullerene PNe likely evolve from low-mass progenitors and are usually of low excitation. We do not find a metallicity dependence on the estimated fullerene abundances. The observed C{sub 60} intensity ratios in the Galactic sources confirm our previous finding in the MCs that the fullerene emission is not excited by the UV radiation from the central star. CLOUDY models also show that line- and wind-blanketed model atmospheres can explain many of the observed [Ne III]/[Ne II] ratios using photoionization, suggesting that possibly the UV radiation from the central star, and not shocks, is triggering the decomposition of the circumstellar dust grains. With the data at hand, we suggest that the most likely explanation for the formation of fullerenes and graphene precursors in PNe is that these molecular species are built from the photochemical processing of a carbonaceous compound with a mixture of aromatic and aliphatic structures similar to that of hydrogenated amorphous carbon dust.

  2. Synthesis of Fullerene-Fused Dioxanes/Dioxepanes: Ferric Perchlorate-Mediated One-Step Reaction of [60]Fullerene with Diols.

    PubMed

    Zhang, Xiao-Feng; Li, Fa-Bao; Wu, Jun; Shi, Ji-Long; Liu, Zhan; Liu, Li

    2015-06-19

    The facile one-step reaction of [60]fullerene with various diols in the presence of ferric perchlorate afforded a series of rare fullerene-fused dioxanes/dioxepanes. Nevertheless, the reaction of [60]fullerene with diethylene glycol, triethylene glycol, and tripropylene glycol promoted by ferric perchlorate unexpectedly generated fullerene-fused dioxanes instead of the anticipated fullerene-fused crown ethers. A plausible reaction mechanism is proposed to explain the formation of fullerene-fused dioxane/dioxepane products. PMID:25996442

  3. Liposomal Formulation of Amphiphilic Fullerene Antioxidants

    PubMed Central

    Zhou, Zhiguo; Lenk, Robert P.; Dellinger, Anthony; Wilson, Stephen R.; Sadler, Robert; Kepley, Christopher L.

    2010-01-01

    Novel amphiphilic fullerene[70] derivatives that are rationally designed to intercalate in lipid bilayers are reported, as well as its vesicular formulation with surprisingly high loading capacity up to 65% by weight. The amphiphilic C70 bisadduct forms uniform and dimensionally stable liposomes with auxiliary natural phospholipids as demonstrated by buoyant density test, particle size distribution and 31P NMR. The antioxidant property of fullerenes is retained in the bipolarly functionalized C70 derivative, Amphiphilic Liposomal Malonylfullerene[70] (ALM) as well as in its liposomal formulations, as shown by both electron paramagnetic resonance (EPR) studies and in vitro reactive oxygen species (ROS) inhibition experiments. The liposomally formulated ALM efficiently quenched hydroxyl radicals and superoxide radicals. In addition, the fullerene liposome inhibited radical-induced lipid peroxidation and maintained the integrity of the lipid bilayer structure. This new class of liposomally formulated, amphipathic fullerene compounds represents a novel drug delivery system for fullerenes and provides a promising pathway to treat oxidative stress-related diseases. PMID:20839887

  4. Fullerene (C60) films for solid lubrication

    SciTech Connect

    Bhushan, B.; Gupta, B.K.; Van Cleef, G.W.; Capp, C.E.; Coe, J.V. (Ohio State Univ., Columbus (United States))

    1993-10-01

    The advent of techniques for producing gram quantities of a new form of stable, pure, solid carbon, designated as fullerene, opens a profusion of possibilities to be explored in many disciplines including tribology. Fullerenes take the form of hollow geodesic domes, which are formed from a network of pentagons and hexagons with covalently bonded carbon atoms. The C60 molecule has the highest possible symmetry (icosahedral) and assumes the shape of a soccer ball. At room temperature, fullerene molecules pack in an fcc lattice bonded with weak van der Waals attractions. Fullerenes can be dissolved in solvents such as toluene and benzene and are easily sublimed. The low surface energy, high chemical stability, spherical shape, weak intermolecular bonding, and high load bearing capacity of C60 molecules offer potential for various mechanical and tribological applications. This paper describes the crystal structure and properties of fullerenes and proposes a mechanism for self-lubricating action. Sublimed films of C60 have been produced and friction and wear performance of these films in various operating environments are the subject of this paper. The results of this study indicate that C60, owing to its unique crystal structure and bonding, may be a promising solid lubricant. 31 refs.

  5. Cathode Ion Bombardment in RF Photoguns

    SciTech Connect

    Pozdeyev,E.; Kayran, D.; Litvinenko, V.

    2008-09-01

    In this paper, we use the method of rapid oscillating field to solve the equation of ion motion in an RF gun. We apply the method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of ions produced in the gun can reach the cathode if no special precautions are taken. Also, the paper proposes a simple mitigation recipe that can reduce the rate of ion bombardment.

  6. Electric dipole emission by fullerenes and buckyonions

    E-print Network

    Susana Iglesias-Groth

    2005-09-15

    We study the rotation rates and electric dipole emission of hydrogenated icosahedral fullerenes (single and multishell) in various phases of the interstellar medium. Using the formalism of Draine and Lazarian for the rotational dynamics of these molecules in various astrophysical environments, we find effective rotation rates in the range 1-65 GHz with a trend toward lower rotational frequency as the radius of the molecule increases. Owing to the moderately polar nature of the C--H bond, hydrogenated fullerenes (fulleranes) are expected to have a net dipole moment and produce electric dipole radiation. Adopting the same size distribution proposed for fullerenes in the study of the UV extinction bump (2175 \\AA) we predict the dipole electric emission of mixtures of fulleranes for various levels of hydrogenation. We find that these molecules could be the carriers of the anomalous microwave emission recently detected by Watson et al. in the Perseus molecular complex.

  7. Nanostructural magnetism of polymeric fullerene crystals

    SciTech Connect

    Sheka, E. F., E-mail: sheka@icp.ac.ru; Zaets, V. A. [Peoples Friendship University (Russian Federation); Ginzburg, I. Ya. [Russian Academy of Sciences, Institute for Problems of Chemical Physics (Russian Federation)

    2006-11-15

    The nature of magnetism in all-carbon crystals composed of polymeric layers of covalently bound fullerene (C{sub 60}) molecules is considered. The results of quantum-chemical calculations performed using the unrestricted Hartree-Fock approximation and the semiempirical AM1 method are presented. It is shown that the exchange integrals J of both a free C{sub 60} molecule and a monomer unit of the polymer are too large ensure the required magnetic susceptibility of the fullerene crystal. However, the J value exhibits an approximately n-fold decrease for an oligomer molecule consisting of n C{sub 60} units. Therefore, in the case of large n, the exchange integral can be reduced to a low level sufficient to provide for a significant magnetic susceptibility. A nanosize (scaly) model of the observed magnetism is proposed that is consistent with recent experimental data, which are indicative of a nanostructural character of magnetic fullerene samples.

  8. Fullerenes in an impact crater on the LDEF spacecraft

    NASA Technical Reports Server (NTRS)

    Radicati di Brozolo, F.; Bunch, T. E.; Fleming, R. H.; Macklin, J.

    1994-01-01

    The fullerenes C60 and C70 have been found to occur naturally on Earth and have also been invoked to explain features in the absorption spectra of interstellar clouds. But no definitive spectroscopic evidence exists for fullerenes in space and attempts to find fullerenes in carbonaceous chondrites have been unsuccessful. Here we report the observation of fullerenes associated with carbonaceous impact residue in a crater on the Long Duration Exposure Facility (LDEF) spacecraft. Laser ionization mass spectrometry and Raman spectroscopy indicate the presence of fullerenes in the crater and in adjacent ejecta. Man-made fullerenes survive experimental hypervelocity (approximately 6.1 km s-1) impacts into aluminium targets, suggesting that space fullerenes contained in a carbonaceous micrometeorite could have survived the LDEF impact at velocities towards the lower end of the natural particle encounter range (<13 km s-1). We also demonstrate that the fullerenes were unlikely to have formed as instrumental artefacts, nor are they present as contaminants. Although we cannot specify the origin of the fullerenes with certainty, the most plausible source is the chondritic impactor. If, alternatively, the impact produced the fullerenes in situ on LDEF, then this suggests a viable mechanism for fullerene production in space.

  9. Fullerenes in an impact crater on the LDEF spacecraft.

    PubMed

    Radicati di Brozolo, F; Bunch, T E; Fleming, R H; Macklin, J

    1994-05-01

    The fullerenes C60 and C70 have been found to occur naturally on Earth and have also been invoked to explain features in the absorption spectra of interstellar clouds. But no definitive spectroscopic evidence exists for fullerenes in space and attempts to find fullerenes in carbonaceous chondrites have been unsuccessful. Here we report the observation of fullerenes associated with carbonaceous impact residue in a crater on the Long Duration Exposure Facility (LDEF) spacecraft. Laser ionization mass spectrometry and Raman spectroscopy indicate the presence of fullerenes in the crater and in adjacent ejecta. Man-made fullerenes survive experimental hypervelocity (approximately 6.1 km s-1) impacts into aluminium targets, suggesting that space fullerenes contained in a carbonaceous micrometeorite could have survived the LDEF impact at velocities towards the lower end of the natural particle encounter range (<13 km s-1). We also demonstrate that the fullerenes were unlikely to have formed as instrumental artefacts, nor are they present as contaminants. Although we cannot specify the origin of the fullerenes with certainty, the most plausible source is the chondritic impactor. If, alternatively, the impact produced the fullerenes in situ on LDEF, then this suggests a viable mechanism for fullerene production in space. PMID:11541208

  10. Ion bombardment experiments suggesting an origin for organic particles in pre-cometary and cometary ices

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1989-01-01

    During the Giotto and Vega encounters with Comet Halley both organic particles called CHON and energetic ions were detected. The acceleration of ions to hundreds of keV in the vicinity of the bow shock and near the nucleus may be a demonstration of a situation occurring in the early solar system (perhaps during the T Tauri stage) that led to the formation of organic particles only now released. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, frozen gases were bombarded at 10 K with 175 keV protons with the result that fluffy solid material remains after sublimation of the ice. Initial experiments were carried out with a gas mixture in parts of 170 carbon monoxide, 170 argon, 25 water, 20 nitrogen, and 15 methane formulated to reflect an interstellar composition in experiments involving the freezing out of the products of a plasma. The plasma experiments resulted in a varnish-like film residue that exhibited luminescence when excited with ultraviolet radiation, while the ion bombardment created particulate material that was not luminescent.

  11. Chemical redox recovery of giant, small-gap and other fullerenes

    Microsoft Academic Search

    James W. Raebiger; John M. Alford; Robert D. Bolskar; Michael D. Diener

    2011-01-01

    A simple method for extracting otherwise insoluble fullerenes into organic solvents is presented. The fullerenes are reduced to anionic charge states by contact with zinc in the presence of an alkylphosphonium salt in tetrahydrofuran. The anionic fullerenes become soluble, and the non-fullerene carbon matrix is separated by filtration. The anionic fullerenes can then be precipitated from solution by the action

  12. A Highly-Ordered 3D Covalent Fullerene Framework.

    PubMed

    Minar, Norma K; Hou, Kun; Westermeier, Christian; Döblinger, Markus; Schuster, Jörg; Hanusch, Fabian C; Nickel, Bert; Ozin, Geoffrey A; Bein, Thomas

    2015-06-22

    A highly-ordered 3D covalent fullerene framework is presented with a structure based on octahedrally functionalized fullerene building blocks in which every fullerene is separated from the next by six functional groups and whose mesoporosity is controlled by cooperative self-assembly with a liquid-crystalline block copolymer. The new fullerene-framework material was obtained in the form of supported films by spin coating the synthesis solution directly on glass or silicon substrates, followed by a heat treatment. The fullerene building blocks coassemble with a liquid-crystalline block copolymer to produce a highly ordered covalent fullerene framework with orthorhombic Fmmm symmetry, accessible 7.5?nm pores, and high surface area, as revealed by gas adsorption, NMR spectroscopy, small-angle X-ray scattering (SAXS), and TEM. We also note that the 3D covalent fullerene framework exhibits a dielectric constant significantly lower than that of the nonporous precursor material. PMID:25958846

  13. Effects of ion and micrometeorite bombardment on mineral surfaces: application to Eros, the Moon, and Mercury

    NASA Astrophysics Data System (ADS)

    Baragiola, R. A.; Loeffler, M. J.; Dukes, C. A.; Chang, W. Y.; Fitz-Gerald, J. M.; McFadden, L. A.

    2004-11-01

    We study in the laboratory the effects of ion and micrometeorite bombardment on mineral surfaces of airless bodies such as asteroids, the Moon, and Mercury. We use 4 keV He and 1 keV H ions to simulate the solar wind and nanosecond laser pulses to simulate micrometeorite impacts. Related to the question of the origin of the Na exospheres around the Moon and Mercury, we studied sputtering of Na from plagioclase feldspars and from Na deposited on olivine and on albite. Chemical characterization of the samples is made by X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), secondary ion mass spectrometry (SIMS), and neutral mass spectrometry. We find that ion bombardment depletes Na from the surface of the feldspars but that the Na segregates back to the surface in a few hours at room temperature. Analysis of the removal of sodium adsorbed on the surface of olivine by He ion irradiation gives a sputtering cross section in line with what is expected for knock-on sputtering, and five orders of magnitude larger than for photo-stimulated desorption. We also determined that the energy distribution of the sputtered ions has a peak at a few eV and a long tail to about 50 eV. Regarding the interpretation of NEAR data from Eros we irradiated powders of olivine with nanosecond 248 nm laser pulses and studied reflectance changes in the visible and near-infrared and chemical changes with XPS. We have collected the ejecta on a quartz-crystal microbalance to quantify the amount of ejecta per pulse. The deposit was found to be crystalline olivine. When collected on a fine-grained olivine surface, it produced visible darkening. We will also report on experiments that serve to explain sulfur depletion at Eros by the solar wind and micrometeorite bombardment. Supported by NASA Cosmochemistry and NEAR Data Analysis Programs.

  14. Energy spectrum of C60 fullerene

    NASA Astrophysics Data System (ADS)

    Mironov, G. I.; Murzashev, A. I.

    2011-11-01

    The energy spectrum of the C60 fullerene has been calculated in terms of the Shubin-Vonsovskii-Hubbard model using an approximation of static fluctuations. Based on the spectrum, the optical absorption bands at 4.84, 5.88, and 6.30 eV observed experimentally have been successfully explained. It has been concluded that the model used is applicable for the calculation of the energy spectrum and the energy properties of other nanosystems, such as fullerenes of higher orders, carbon nanotubes, and grafen planes.

  15. Formalism of collective electron excitations in fullerenes

    NASA Astrophysics Data System (ADS)

    Verkhovtsev, A.; Korol, A. V.; Solov'yov, A. V.

    2012-10-01

    A formalism for the description of collective electron excitations in fullerenes by inelastic scattering of fast electrons within the plasmon resonance approximation is presented. Considering the system as a spherical shell of a finite width, we show that the differential cross section is defined by three plasmon excitations, namely two coupled modes of the surface plasmon and the volume plasmon. The interplay of the three plasmons appears due to the electron diffraction of the fullerene shell. Plasmon modes of different angular momenta provide dominating contributions to the differential cross section depending on the transferred momentum.

  16. Low activation energy fullerene molecular resist

    Microsoft Academic Search

    J. Manayam; M. Manickam; J. A. Preece; R. E. Palmer; A. P. G. Robinson

    2009-01-01

    Recently there has been significant interest in the field of molecular resists as a route to shrinking the trade-off between resolution, line width roughness and sensitivity for next generation lithography. We have previously presented initial results of a three component fullerene derivative based negative tone chemically amplified electron beam resist with sparse feature resolution of ~12 nm, half pitch resolution

  17. Endohedral fullerenes for organic photovoltaic devices

    Microsoft Academic Search

    Russel B. Ross; Claudia M. Cardona; Dirk M. Guldi; Shankara Gayathri Sankaranarayanan; Matthew O. Reese; Nikos Kopidakis; Jeff Peet; Bright Walker; Guillermo C. Bazan; Edward van Keuren; Brian C. Holloway; Martin Drees

    2009-01-01

    So far, one of the fundamental limitations of organic photovoltaic (OPV) device power conversion efficiencies (PCEs) has been the low voltage output caused by a molecular orbital mismatch between the donor polymer and acceptor molecules. Here, we present a means of addressing the low voltage output by introducing novel trimetallic nitride endohedral fullerenes (TNEFs) as acceptor materials for use in

  18. Amino acid and peptide derivatives of fullerene

    Microsoft Academic Search

    M. E. Vol'pin; Z. N. Parnes; V. S. Romanova

    1998-01-01

    A general method for the synthesis of amino acid and peptide derivatives of fullerene (ADF) was developed, and the physicochemical\\u000a properties of the compounds obtained were studied. ADF were shown to penetrate into liposomes and to exhibit adjuvant properties\\u000a and antiviral activity.

  19. Cobalt silicide formation induced by oxygen ion bombardment

    Microsoft Academic Search

    S. C. Edwards; R. A. Collins; G. Dearnaley

    1989-01-01

    Oxygen ion bombardment of the Co\\/Si and Co\\/SiOx\\/Si systems has been studied with regard to the effects on the ion-induced formation of cobalt silicides. Dose-dependence experiments have shown that with increasing total dose the phase formed upon post-bombardment annealing was Co2Si (rather than the expected disilicide). Similarly, samples annealed after bombardment at elevated temperatures were also found to result in

  20. Hydrodynamic model of wave-ordered structures formed by ion bombardment of solids

    NASA Astrophysics Data System (ADS)

    Rudy, A. S.; Smirnov, V. K.

    1999-10-01

    The model of a wave-ordered structures (WOS) formed by ion-bombardment on a surfaces of amorphous materials is put forward. The model is based on the assumption that amorphous layer under ion-bombardment may be considered as Newtonian fluid on a hard substrate in the field of external force. Within this approach the mathematical model of an amorphous layer is formulated as a boundary value problem for Navier-Stokes and continuity equations for incompressible liquid. Analysis of the problem results in two quasi-stationary spatial-periodic solutions governed by two control parameters: one of them a? is a capillary constant under a vertical ion beam incidence, normalized to layer thickness, another is an angle of incidence ?. In the general case a capillary constant a?(L,?) is a convex function of both variables viz. normalized spatial-period L and an angle of incidence ?. With energy E0=9 keV this function exhibits a local maximum at L=1.77,?=50.4? which is already global a?c=0.375 when E0=5 keV and (as judged by indirect measurements) becomes more convex with further energy reduction. Collation of a?(L,?) with experimental data reveals that the observed maximum value of capillary constant a?ob=0.367, which due to an inherent supercriticality is a little bit lower than a?c, falls at ?=55?, i.e., with energy diminution angular range should contract to this point. This outcome is consistent with our experimental results on N2+-Si system, manifesting that angular range reduces to a small vicinity of ?cin=55? when ion energy tends to minimum energy of WOS formation E0=1.5 keV.

  1. Compositional instability and elemental redistribution in Hg1-xCdxTe induced by low-energy ion bombardment

    NASA Astrophysics Data System (ADS)

    Zhang, Huadong; Xia, Yueyuan; Fang, Jiaxiong

    2000-12-01

    Monte Carlo simulations are used to study the compositional changes in the near surface layer of HG-xCdxTe crystal substrate induced by F+ and Ar+ ion bombardment in the energy range of 0.1 to 5keV. The effects of the crystal structure of the substrate and the total dose used in the bombardment are involved in the simulations. Due to the preferential sputtering for different elements in the substrate and the difference of the displacement energies for these elements, remarkable redistribution of the constituent elements in the material are observed. The possibility of forming p-n junction by using the Hg enrichment layer near the surface as a diffusion source is discussed.

  2. Study of endohedral doped C60 fullerene using model potentials

    NASA Astrophysics Data System (ADS)

    Umran, N. M.; Kaur, Narinder; Seema, K.; Kumar, Ranjan

    2015-05-01

    In this paper, we present a study of Si, Ge, Au and Tl doped endohedral fullerenes using model potentials. We have used Brenner potential, Lennard-Jones potential and Gupta potential to describe the C–C (Si, Ge), C–metal and metal–metal interaction, respectively. We have done total energy calculations to find out the minimum energy structures. In the case of Sin@C60 complex, a maximum of nine atoms can be doped inside the fullerene cage. The addition of a tenth Si atom leads to the breaking of the fullerene cage. Similarly for Ge, Au and Tl, a maximum of four, two and two atoms, respectively, can be doped inside the fullerene cage. It has been observed that the stability of fullerene decreases with an increase in the number of dopant atoms. These calculations prove the change of characteristics of fullerenes upon doping.

  3. Alignment strategies for fullerenes and their dimers using soft matter

    NASA Astrophysics Data System (ADS)

    Campbell, Katie

    The overall goal of this research was to achieve alignment of endohedral fullerene dimers defined as covalently linked pairs of fullerene cages where each fullerene cage encapsulates a spin-active atom. The first section will discuss polymer-fullerene interactions from the point of view of determining how various polymer functional groups enhance or hinder the miscibility of C60. In order to successfully incorporate fullerenes into a block copolymer system, we first need to understand the basic interactions that occur between polymers and fullerenes to anticipate the upper limit of fullerenes that may be incorporated in a given polymer and potential approaches to increase this quantity. In particular, studies conducted using wide angle x-ray scattering (WAXS) of vinyl polymer-fullerene blends indicated that an increasing number of phenyl rings in the vinyl side group of the polymer leads to an increase in the miscibility. In particular, poly(9-vinylphenanthrene) (P9VPh), having three phenyl rings in the side group, showed a 6-fold improvement in miscibility limit compared to the other systems studied, polystyrene (PS) and poly(2-vinylnaphathalene) (P2VN). The degree of increase in miscibility observed with P9VPh is attributed to the ability of the vinyl aromatic structure to essentially conform to the curvature of a fullerene molecule rather than the increased potential for pi-pi interactions. These results importantly suggest that a block copolymer system can be tuned to maximize fullerene content, particularly by considering the geometry of functional groups with respect to the fullerene cage and will be discussed further in Chapter III. Second, the use of block copolymers as templates for creating ordered arrays of fullerenes is discussed. The initial goal was to disperse the fullerenes in one block of a block copolymer system and by aligning the microphase separation structure, also align the incorporated fullerenes. There are several major challenges associated with incorporating fullerenes into a block copolymer including the limited miscibility discussed in Chapter III. Furthermore, overcoming the strong inter-fullerene interactions that lead to aggregation also proves to be challenging; aggregates can disrupt the microphase structure in a block copolymer and make alignment difficult to obtain. One potential method generically used to solubilize nanoparticles within a block copolymer is modification of the nanoparticles by grafting polymer chains to the surface to solubilize the nanoparticle in a specific block. As discussed in Chapter IV, the effects of nanoparticle size and concentration on the phase behavior of lamellar-forming dPS-PMMA systems as well as the location of the fullerene star within the dPS block were studied using neutron reflectivity (NR). The scheme above has the disadvantage that modification of the fullerene cage with polymer arms dilutes the overall quantity of fullerene in the system and in the case of endohedral systems, would dilute and severely limit the overall quantity of spins available for measurement in quantum computing. For this reason we chose to investigate the formation of monolayers of amphiphilic fullerene dimers at the air/water interface using the Langmuir technique. We also studied the behavior of these materials when transferred as monolayers and multilayers to solid substrates as Langmuir-Blodgett (LB) films. The fullerene dimers in this case were modified to have at least one hydrophilic, polyethylene glycol-based ligand to balance the inherently hydrophobic nature of the fullerene cage and allow for a molecule that more closely resembled typical LB materials. Results of these studies indicated that we can form stable, close-packed monolayers and also control the orientation of the dimer at the air/water interface as well as on solid substrates by tuning the ligand chemistry as shown in Chapter V. The final approach used to achieve alignment of fullerene materials involves the interaction of fullerenes with a chemically-modified substrate either covalently or non-covale

  4. Fullerene-based materials research and development. LDRD final report

    SciTech Connect

    Cahill, P A; Henderson, C C; Rohlfing, C M; Loy, D A; Assink, R A; Gillen, K T; Jacobs, S J; Dugger, M T

    1995-05-01

    The chemistry and physical properties of fullerenes, the third, molecular allotrope of carbon, have been studied using both experimental and computational techniques. Early computational work investigated the stability of fullerene isomers and oxides, which was followed by extensive work on hydrogenated fullerenes. Our work led to the first synthesis of a polymer containing C{sub 60} and the synthesis of the simplest hydrocarbon derivatives of C{sub 60} and C{sub 70}. The excellent agreement between theory and experiment ({plus_minus} 0.1 kcal/mol in the relative stability of isomers) has provided insight into the chemical nature of fullerenes and has yielded a sound basis for prediction of the structure of derivatized fullerenes. Such derivatives are the key to the preparation of fullerene-based materials.

  5. Optical limiting processes in derivatized fullerenes and porphyrins/phthalocyanines

    SciTech Connect

    Kohlman, R.; Klimov, V.; Shi, X. [and others

    1998-07-01

    The authors review their results from spectral studies of the ultrafast excited-state absorption in fullerenes and derivatized fullerenes. These results allow determination of both the spectral response of reverse saturable absorption (RSA) nonlinearities such as optical limiting (OL) in fullerenes, and the dynamical response for different morphologies. The authors have investigated the effects of thin film and various sol-gel glass environments on the nanosecond OL and femtosecond dynamics of derivatized fullerenes. These data provide evidence of decay pathways which compete with the intersystem crossing to a triplet from the initial singlet states. With appropriate processing, however, the OL response of derivatized-fullerene sol-gel glasses can be enhanced to approach that of the same molecule in solution, while significantly enhancing the optical damage threshold. The optical limiting of these derivatized fullerenes is compared with that of various porphyrin and phthalocyanine molecules.

  6. Fullerenes: An extraterrestrial carbon carrier phase for noble gases

    PubMed Central

    Becker, Luann; Poreda, Robert J.; Bunch, Ted E.

    2000-01-01

    In this work, we report on the discovery of naturally occurring fullerenes (C60 to C400) in the Allende and Murchison meteorites and some sediment samples from the 65 million-year-old Cretaceous/Tertiary boundary layer (KTB). Unlike the other pure forms of carbon (diamond and graphite), fullerenes are extractable in an organic solvent (e.g., toluene or 1,2,4-trichlorobenzene). The recognition of this unique property led to the detection and isolation of the higher fullerenes in the Kratschmer/Huffmann arc evaporated graphite soot and in the carbon material in the meteorite and impact deposits. By further exploiting the unique ability of the fullerene cage structure to encapsulate and retain noble gases, we have determined that both the Allende and Murchison fullerenes and the KTB fullerenes contain trapped noble gases with ratios that can only be described as extraterrestrial in origin. PMID:10725367

  7. Modulation transfer function and detective quantum efficiency of electron bombarded charge coupled device detector for low energy electrons

    SciTech Connect

    Horacek, Miroslav [Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Kralovopolska 147, CZ-61264 Brno (Czech Republic)

    2005-09-15

    The use of a thinned back-side illuminated charge coupled device chip as two-dimensional sensor working in direct electron bombarded mode at optimum energy of the incident signal electrons is demonstrated and the measurements of the modulation transfer function (MTF) and detective quantum efficiency (DQE) are described. The MTF was measured for energy of electrons 4 keV using an edge projection method and a stripe projection method. The decrease of the MTF for a maximum spatial frequency of 20.8 cycles/mm, corresponding to the pixel size 24x24 {mu}m, is 0.75{approx_equal}-2.5 dB, and it is approximately the same for both horizontal and vertical directions. DQE was measured using an empty image and the mixing factor method. Empty images were acquired for energies of electrons from 2 to 5 keV and for various doses, ranging from nearly dark image to a nearly saturated one. DQE increases with increasing energy of bombarded electrons and reaches 0.92 for electron energy of 5 keV. For this energy the detector will be used for the angle- and energy-selective detection of signal electrons in the scanning low energy electron microscope.

  8. Polythermal solubility of fullerenes in higher isomeric carboxylic acids

    Microsoft Academic Search

    K. N. Semenov; O. V. Arapov; A. K. Pyartman; V. A. Keskinov; V. V. Lishchuk; N. A. Charykov; N. I. Alekseev

    2007-01-01

    The solubility of individual fullerenes C60 and C70 and a fullerene mixture enriched in higher fullerenes (C60 38.8, C70 33.0, C76–78 5.6, C84 8.6, C90 2.6, and C96 3.3%) in higher isomeric carboxylic acids was studied within the 20–80C temperature range; the corresponding solubility\\u000a polytherms are presented.

  9. Aerosol Synthesis of Fullerene Nanocrystals in Controlled Flow Reactor Conditions

    Microsoft Academic Search

    J. Joutsensaari; P. P. Ahonen; E. I. Kauppinen; D. P. Brown; K. E. J. Lehtinen; J. K. Jokiniemi; B. Powels; G. Van Tendeloo

    2000-01-01

    Fullerene nanocrystals in the size range 30–300 nm were produced starting from atomized droplets of C60 in toluene. The experiments were carried out under well-controlled conditions in a laminar flow reactor at temperatures of 20–600°C. Particle transformation and crystallization mechanisms of polydisperse and monodisperse (size classified) fullerene aerosol particles were studied. The results show that fullerene particles are roughly spherical

  10. Supramolecular pentapeptide-based fullerene nanofibers: effect of molecular chirality.

    PubMed

    Insuasty, Alberto; Atienza, Carmen; López, Juan Luis; Martín, Nazario

    2015-06-16

    The supramolecular organization of new fullerene derivatives endowed with peptides as biomolecular templates affords ordered nanofibers of several micrometres length based on hydrogen bonds and ?-? interactions. PMID:26037709

  11. Ioninduced electron emission as a means of studying energy- and angle-dependent compositional changes of solids bombarded with reactive ions

    Microsoft Academic Search

    K. Wittmaack

    1999-01-01

    Ion-induced electron yields ? of n-type silicon bombarded with O+ and O+2 ions at energies between 1 and 12.5keV have been measured at impact angles ? between 0° (normal incidence) and 86°, both for sputter-cleaned samples and under conditions of stationary loading with oxygen. The electron yields were determined by target current measurements. To avoid yield deficits due to charging

  12. Ioninduced electron emission as a means of studying energy- and angle-dependent compositional changes of solids bombarded with reactive ions

    Microsoft Academic Search

    Y. Kataoka; K. Wittmaack

    1999-01-01

    Target current measurements were used to determine ion-induced electron yields ? of silicon bombarded with 2–10keV N+2 ions at impact angles ? between 0° (normal incidence) and 84°, both for sputter-cleaned samples and under conditions of full loading with nitrogen. At normal incidence, the electron yields of nitrogen saturated samples ?sat0 were much higher than the yields ?00 of clean

  13. Erratum: Ion bombardment into inner wall surfaces of tubes and their biomedical applications (Nuclear Instruments and Methods in Physics Research B (1995) 106 (618))

    NASA Astrophysics Data System (ADS)

    Iwaki, M.; Nakao, A.; Kaibara, M.; Sasabe, H.; Kaneko, S.; Nakajima, H.; Suzuki, Y.; Kusakabe, M.; Fujihana, T.

    1996-07-01

    A study has been made of ion bombardment into the inner wall surfaces of tubes to develop hybrid type, small diameter artificial vascular grafts. Substrates used were polystyrene with an inside diameter of 2 mm and segmented polyurethane (SPU) coated glass tube with an inside diameter of 1.5 mm. Ne-ion bombardment into inner wall surfaces of tubes was performed at an energy of 150 keV with an average fluence of 4 × 10 14 ions/cm 2 at an incident angle of about 88.3°. The surface modification of inner wall surfaces was examined by X-ray photoelectron spectroscopy, which showed the presence of amorphous carbon structures in the inner surfaces of Ne bombarded tubes. Endothelialization was performed on the Ne-bombarded SPU coated inner wall of a glass tube, although it could not be done without ion bombardment. A femoral artery has been replaced by the new artificial graft, and exposed to blood for 24 hours. The new graft demonstrated 100% patency. The development of artificial vascular grafts will be feasible by ion beam modification of inner wall surfaces of tubes.

  14. Transformation of cotton ( Gossypium hirsutum L.) via particle bombardment

    Microsoft Academic Search

    John J. Finer; Michael D. McMullen

    1990-01-01

    Embryogenic suspension cultures of cotton (Gossypium hirsutum L.) were subjected to particle bombardment, where high density particles carrying plasmid DNA were accelerated towards the embryogenic plant cells. The plasmid DNA coating the particles encoded hygromycin resistance. One to two weeks following bombardment, embryogenic cotton cells were placed in proliferation medium containing 100 µg\\/ml hygromycin. Clumps of tissue which grew in

  15. THE BEHAVIOUR OF CARBON STRIPPER FOILS UNDER HEAVY ION BOMBARDMENT

    E-print Network

    Boyer, Edmond

    bombarded whith 4.8 MeV A++ ions in a hydrocarbon-free vacuum environment has been investigated Graaff accelerator using a conventio- nal vacuum system. The foils, produced by evapora- tion from a carbon arc, were found to thicken consi- derably when bombarded at room temperature at current densities

  16. Formation of sputtered silver clusters under bombardment with SF

    E-print Network

    Wucher, Andreas

    Formation of sputtered silver clusters under bombardment with SFþ 5 ions S. Ghalab a , C. Staudt clusters and Agþ n cluster ions under bombardment of a silver surface with SFþ 5 and Xeþ projectile ions of Experimental Physics, University of Essen, D-45117 Essen, Germany b Cluster Physics Laboratory, Arifov

  17. Self sputtering yields of silver under bombardment with polyatomic projectiles

    E-print Network

    Wucher, Andreas

    Self sputtering yields of silver under bombardment with polyatomic projectiles A. Duvenbeck, M: Molecular dynamics simulations; Sputtering; Nonlinear effects; Cluster bombardment; Collisional Spikes 1 projectiles, i.e. clusters composed of several atoms. Andersen and Bay [1] as well as Thompson and Johar [2

  18. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 18 July 1942- 7 February 1943 

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Missions: 18 July 1942 ? 7 February 1943. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical... 42nd Bombardment Squadron (H) Missions: 18 July 1942 ? 7 February 1943. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical...

  19. Carbon and fullerene nanomaterials in plant system.

    PubMed

    Husen, Azamal; Siddiqi, Khwaja Salahuddin

    2014-01-01

    Both the functionalized and non functionalized carbon nanomaterials influence fruit and crop production in edible plants and vegetables. The fullerene, C60 and carbon nanotubes have been shown to increase the water retaining capacity, biomass and fruit yield in plants up to ~118% which is a remarkable achievement of nanotechnology in recent years. The fullerene treated bitter melon seeds also increase the phytomedicine contents such as cucurbitacin-B (74%), lycopene (82%), charantin (20%) and insulin (91%). Since as little as 50 ?g mL-1 of carbon nanotubes increase the tomato production by about 200%, they may be exploited to enhance the agriculture production in future. It has been observed that, in certain cases, non functionalized multi-wall carbon nanotubes are toxic to both plants and animals but the toxicity can be drastically reduced if they are functionalized. PMID:24766786

  20. Diamond films grown from fullerene precursors

    SciTech Connect

    Gruen, D.M.; Zuiker, C.D.; Krauss, A.R.

    1995-07-01

    Fullerene precursors have been shown to result in the growth of diamond films from argon microwave plasmas. In contradistinction to most diamond films grown using conventional methane-hydrogen mixtures, the fullerene-generated films are nanocrystalline and smooth on the nanometer scale. They have recently been shown to have friction coefficients approaching the values of natural diamond. It is clearly important to understand the development of surface morphology during film growth from fullerene precursors and to elucidate the factors leading to surface roughness when hydrogen is present in the chemical vapor deposition (CVD) gas mixtures. To achieve these goals, we are measuring surface reflectivity of diamond films growing on silicon substrates over a wide range of plasma processing conditions. A model for the interpretation of the laser interferometric data has been developed, which allows one to determine film growth rate, rms surface roughness, and bulk losses due to scattering and absorption. The rms roughness values determined by reflectivity are in good agreement with atomic force microscope (AFM) measurements. A number of techniques, including high-resolution transmission electron microscopy (HRTEM) and near-edge x-ray absorption find structure (NEXAFS) measurements, have been used to characterize the films. A mechanism for diamond-film growth involving the C{sub 2} molecule as a growth species will be presented. The mechanism is based on (1) the observation that the optical emission spectra of the fullerene- containing plasmas are dominated by the Swan bands of C{sub 2} and (2) the ability of C{sub 2} to insert directly into C-H and C-C bonds with low activation barriers, as shown by recent theoretical calculations of reactions of C{sub 2} with carbon clusters.

  1. Mass spectrometry of fluoroalkyl substituted fullerenes

    SciTech Connect

    McEwen, C.N.; Krusic, P.J.; Fagan, P.J. [E.I. du Pont de Nemours & Co., Wilmington, DE (United States)

    1994-12-31

    Mass spectrometry has played a significant role in the discovery of fullerenes and in the analysis of their chemical derivatives. Because these electron deficient spherical polyene structures readily attach electrons to produce stable anions, negative ionization methods are frequently used in the analysis of these materials by mass spectrometry. Addition of electron withdrawing substituents to buckminsterfullerene should increase the cross-section for electron attachment and make these compounds even more susceptible to analysis by negative ion mass spectrometry.

  2. Color-tunable photoluminescent fullerene nanoparticles.

    PubMed

    Jeong, Jinyoung; Jung, Juyeon; Choi, Mijin; Kim, Ju Whan; Chung, Sang J; Lim, Sujin; Lee, Han; Chung, Bong Hyun

    2012-04-17

    Highly water-soluble and color-tunable photoluminescent fullerene nanoparticles are synthesized by using tetraethylene glycol (TEG) and lithium hydroxide as a catalyst. The maximum PL emission changes depend on the contents of the remaining ?-conjugation in oxidized C(60), which is partially covalently conjugated with TEG. The PL behavior is attributed to an electronic transition change due to the distortion of symmetrical C(60). PMID:22431377

  3. Feasibility of fullerene waste as carbonaceous adsorbent

    Microsoft Academic Search

    Theodore G. Cleveland; Sanjay Garg; William G. Rixey

    1996-01-01

    This note investigates using the waste soot generated in fullerene manufacture as an adsorbent. Both oven-dried and air-activated samples of waste soot are compared with three commercially available powdered activated carbons (PACs): Nuchar-SA, HDH, and Calgon-RC. Three model compounds were chosen for adsorption tests--TCE, Benzene, and Phenol--representing a small branched molecule, a small nonpolar ring molecule, and relatively polar ring

  4. Enhanced optical limiting in derivatized fullerenes

    Microsoft Academic Search

    L. Smilowitz; D. McBranch; V. Klimov; J. M. Robinson; A. Koskelo; M. Grigorova; B. R. Mattes; H. Wang; F. Wudl

    1996-01-01

    We have observed enhanced optical limiting behavior in solutions of a derivatized fullerene (phenyl-Cââ-butyric acid cholesteryl ester) from 532 to 700nm. Transient absorption measurements determined the spectral and temporal regions of interest for optical limiting in Cââ and in Cââ derivatives that are due to a reverse saturable absorption mechanism and predicted enhanced limiting at longer wavelengths. Intensity-dependent transmission measurements

  5. Nanostructural magnetism of polymeric fullerene crystals

    Microsoft Academic Search

    E. F. Sheka; V. A. Zaets; I. Ya. Ginzburg

    2006-01-01

    The nature of magnetism in all-carbon crystals composed of polymeric layers of covalently bound fullerene (C60) molecules is considered. The results of quantum-chemical calculations performed using the unrestricted Hartree-Fock approximation\\u000a and the semiempirical AM1 method are presented. It is shown that the exchange integrals J of both a free C60 molecule and a monomer unit of the polymer are too

  6. Thermoelectricity in fullerene-metal heterojunctions.

    PubMed

    Yee, Shannon K; Malen, Jonathan A; Majumdar, Arun; Segalman, Rachel A

    2011-10-12

    Thermoelectricty in heterojunctions, where a single-molecule is trapped between metal electrodes, has been used to understand transport properties at organic-inorganic interfaces. (1) The transport in these systems is highly dependent on the energy level alignment between the molecular orbitals and the Fermi level (or work function) of the metal contacts. To date, the majority of single-molecule measurements have focused on simple small molecules where transport is dominated through the highest occupied molecular orbital. (2, 3) In these systems, energy level alignment is limited by the absence of electrode materials with low Fermi levels (i.e., large work functions). Alternatively, more controllable alignment between molecular orbitals and the Fermi level can be achieved with molecules whose transport is dominated by the lowest unoccupied molecular orbital (LUMO) because of readily available metals with lower work functions. Herein, we report molecular junction thermoelectric measurements of fullerene molecules (i.e., C(60), PCBM, and C(70)) trapped between metallic electrodes (i.e., Pt, Au, Ag). Fullerene junctions demonstrate the first strongly n-type molecular thermopower corresponding to transport through the LUMO, and the highest measured magnitude of molecular thermopower to date. While the electronic conductance of fullerenes is highly variable, due to fullerene's variable bonding geometries with the electrodes, the thermopower shows predictable trends based on the alignment of the LUMO with the work function of the electrodes. Both the magnitude and trend of the thermopower suggest that heterostructuring organic and inorganic materials at the nanoscale can further enhance thermoelectric performance, therein providing a new pathway for designing thermoelectric materials. PMID:21882860

  7. Optical Properties of Fullerene-Based Materials

    Microsoft Academic Search

    Ying Wang

    1993-01-01

    In this dissertation I have presented results of my optical studies of fullerene-based solids: pristine solid C_{60}, alkali-metal (M) doped C_{60} rm(M_6C_{60}) and phototransformed C_{60}.. Raman scattering and infrared spectroscopy were used to study the vibrational modes and it was found that modes observed experimentally were intramolecular modes whose frequencies were found in reasonable agreement with theoretical predictions for an

  8. Bombarding insulating foils with highly energetic ions

    NASA Astrophysics Data System (ADS)

    Lanzanò, G.; de Filippo, E.; Hagmann, S.; Rothard, H.; Volant, C.

    Insulating (MYLAR), semi-insulating (MYLAR-Au) and conducting foils have been bombarded by very energetic 64 MeV u-1 78Kr32+ ions. The velocity spectra of fast electrons emitted in the backward and forward directions have been measured and analyzed as a function of the elapsed time in the run. A shift of binary encounter and convoy electrons emitted in the forward direction toward lower velocities has been observed with insulating targets. No such shift occurs with metallic targets. The surface potential evolves with time (i.e. ion fluence) both at forward and backward emission angle. It is shown that strong bulk charging of insulating targets leads to a positive potential as high as 9 kV before charge breakdown.

  9. DDT_dgarciah_3: Searching for complex fullerene-based molecules in the prototype fullerene Planetary Nebula IC 418

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.

    2013-02-01

    The recent and unexpected detection of the most common fullerenes (C60 and C70) and proto-graphene in some Planetary Nebulae (PNe) raises the exciting possibility that other more complex fullerene-based molecules (e.g., carbon onions or multishell fullerenes, fullerene-adducts) might be ubiquitous in the Universe and continue to be serious candidates to explain many astrophysical phenomena. The presence of complex fullerene-based molecules such as carbon onions in the circumstellar shells of fullerene-containing PNe is strongly suggested by our recent analysis of the unusual diffuse interstellar bands detected towards two PNe where C60 had already been found. If complex fullerene-based molecules such as carbon onions are present in this peculiar class of stars, they could easily be detected in the far-IR range. Fullerene-containing PNe are usually very faint in the far-IR but our very recent detection of C60 fullerenes in PN IC 418 can now mitigate this unfortunate situation. Surprisingly, Herschel has not observed this very bright source - now considered the prototype fullerene-containing PN - as part of any approved program in previous cycles. Thus, a comprehensive far-IR study of the complex circumstellar environment where fullerenes and fullerene-based molecules may form is at present lacking. With this DDT proposal we aim at obtaining full range, high S/N, Herschel/PACS far-IR spectra of PN IC 418 to search for the spectral signatures of complex fullerene-based molecules such as multishell fullerenes (e.g., C60@C240, C240@C960), which are predicted to be detectable as relatively strong broad features in the far-IR range. If successful, these observations will constitute the first firm detection of the most complex molecules ever detected in space. In addition, we will search for the predicted hydrogenated amorphous carbon (HAC) associated feature at ~60 um to confirm/refute the HAC's processing/decomposition scenario as the preferred fullerene formation route in PNe.

  10. Electron emission from glow-discharge cathode materials due to neon and argon ion bombardment

    NASA Astrophysics Data System (ADS)

    Szapiro, B.; Rocca, J. J.

    1989-05-01

    The electron yields of 7 glow-discharge cathode materials under bombardment by neon and argon ions with energies between 1 and 20 keV were measured. The surfaces of the samples were conditioned by operating the materials as cold cathodes in a high-voltage glow discharge before the electron yield measurement. The materials studied are oxidized magnesium, oxidized aluminum, a molybdenum-aluminum oxide sintered composite, molybdenum, stainless steel, copper, and graphite. The dependence of electron yield on ion velocity was found to be approximately linear for all materials and gases, with the slopes being strongly material dependent. The corresponding glow-discharge current intensities were observed to have a supralinear dependence on the electron yield. The results are relevant to the design and modeling of cold cathode high-voltage glow discharges.

  11. Ultrabroadband terahertz field detection by proton-bombarded InP photoconductive antennas.

    PubMed

    Liu, Tze-An; Tani, Masahiko; Nakajima, Makoto; Hangyo, Masanori; Sakai, Kiyomi; Nakashima, Shin-Ichi; Pan, Ci-Ling

    2004-06-28

    Photoconductive (PC) antennas fabricated on InP bombarded with 180 keV protons of different dosages (InP:H+) all exhibit a useful bandwidth of about 30 THz, comparable to that of the LT-GaAs PC antenna. The peak signal current of the best InP: H+ device (dosage of 10;15 ions/cm;2) is slightly higher than that of the LT-GaAs one, while the signal-to-noise ratio (SNR) of the former is about half of that of the latter due to lower resistivity. This suggests that InP: H+ can be a good substrate for THz PC antennas with proper annealing and/or implantation recipe. PMID:19483812

  12. C 2H 4 insertion into ion-bombarded porous silica

    NASA Astrophysics Data System (ADS)

    Cerofolini, G. F.; Conti, G.; Garbasso, G. M.; Spaggiari, C.; Meda, L.

    1997-06-01

    A study via infrared and X-ray-photoelectron spectroscopies of ethylene reactions with porous silica during high-energy (300 keV) argon bombardment in a C 2H 4 atmosphere, followed by exposure to air at room temperature or heating at 500°C in a vacuum, is reported. This study has revealed in the as-prepared sample the presence of C?C, C?O, CH 2 and CH 3 groups. Aging at room temperature in a nitrogen atmosphere as well as in air produced an increase of CH 3 and C?O amount, while a heat treatment at 500°C produced the following: the disappearance of C?C and C?O groups, an increase in the CH 2 amount, and a decrease in the CH 3 amount. An interpretation for this behaviour is proposed. A previous conclusion concerning CO 2 addition to ion-bombarded porous silica, that approximately 10 2 oxygen-bridge vacancy per impinging ion are stabilized through the addition of gas molecules, is confirmed by the present work.

  13. Influence of primary ion bombardment conditions on the emission of molecular secondary ions

    NASA Astrophysics Data System (ADS)

    Kersting, R.; Hagenhoff, B.; Kollmer, F.; Möllers, R.; Niehuis, E.

    2004-06-01

    In order to further our understanding of the secondary ion emission behavior from organic surfaces, we have performed a systematic study on the influence of the primary ion parameters. As model sample Irganox 1010 on low density polyethylene (LDPE) was used. Both monoatomic (Ga, Cs, Au) and polyatomic (Au 2, Au 3, SF 5, C 60) primary ions were used. Additionally, the primary ion energy was varied. The data were evaluated by calculating secondary ion yields, disappearance cross sections and ion formation efficiencies (yield/damage cross section). The results show that heavier monoatomic ions are more efficient than lighter ones and that polyatomic primary ions are more efficient than monoatomic ones. Highest efficiency values are found for C 60 bombardment at 20 keV. Compared to Ga bombardment the efficiency gain in this case is more than 2000-fold. Additionally it can be shown that the higher efficiency is correlated with a softer ionization, i.e. less fragmentation. The results suggest a much more homogeneous energy distribution in the sample surface by polyatomic primary ions compared to monoatomic ones.

  14. Fullerene C60: Surface Energy and Interfacial Interactions in Aqueous Systems

    EPA Science Inventory

    The underlying mechanisms of fullerene-fullerene, fullerene-water, and fullerene-soil surface interactions in aqueous systems are not well understood. To advance our understanding of these interfacial interactions, the surface properties of Buckminsterfullerene (C60) and quartz s...

  15. FORMATION PROCESS OF EMPTY AND METAL-CONTAINING FULLERENE

    E-print Network

    Maruyama, Shigeo

    Engineering and b Engineering Research Institute, The University of Tokyo, Tokyo, Japan ABSTRACT The formationFORMATION PROCESS OF EMPTY AND METAL-CONTAINING FULLERENE MOLECULAR DYNAMICS AND FT-ICR STUDIES compared with empty fullerene formation simulation. FT-ICR mass spectrometer directly connected

  16. Three dimensional aromaticity, elemental boron and stuffed fullerenes

    SciTech Connect

    Jemmis, E.D. [Univ. of Hyderabad (India)

    1994-12-31

    An intriguing aspect of fullerenes is the large empty space within. It has been possible to use this space as a molecular container encapsulating neutral atoms and metal ions. A few atoms do not fill the available space. To stuff fullerenes a systematic chemical binding of atoms or molecules to the endohedral surface is needed.

  17. Nonlinear Optical Response in Higher Fullerenes Kikuo Harigaya

    E-print Network

    Harigaya, Kikuo

    Nonlinear Optical Response in Higher Fullerenes Kikuo Harigaya Physical Science Division these lines remain unchanged even though your preprint looks a bit ugly.) Nonlinear optical properties nonlinearities of higher fullerenes are a few times larger than those of C60. The magnitudes of nonlinearity tend

  18. Optical absorption spectra and geometric e ects in higher fullerenes

    E-print Network

    Harigaya, Kikuo

    Optical absorption spectra and geometric e ects in higher fullerenes (Running head: Optical absorption in higher fullerenes) Kikuo Harigaya and Shuji Abe Physical Science Division, Electrotechnical of their amplitudes at the pentagons. The oscillator strengths of projected absorption almost accord with those

  19. Nitrogen Adsorption by Activated Carbon Saturated with Fullerenes

    Microsoft Academic Search

    V. Grekhov; J. Kalnacs; A. Murashov; A. Vilken

    2010-01-01

    The ability of activated coal (AC) to capture and hold fullerenes is associated with the AC pore structure and considerably differs for different ACs. To reveal the nature of the AC holding capacity, the authors studied adsorption of nitrogen by AC samples at 77K after treatment by C60 fullerene. For measurements, an Autosorb-1 (Quantachrome Instrument Co., Florida, USA) device was

  20. Synthesis of fullerenic nanocapsules from bio-molecule carbonisation

    Microsoft Academic Search

    Shik Chi Tsang; Jieshan Qiu; Peter J. F Harris; Qi Jia Fu; Ning Zhang

    2000-01-01

    There has been great interest in the incorporation of foreign materials into fullerene structures (C60, nanotubes, nanoparticles, onions). This interest has been driven by the potential applications of the filled fullerenes, which lie in areas as diverse as optical, electronic, magnetic recording materials and nuclear medicine. In particular, the onion structures of extreme strength may offer excellent protection to their

  1. The development of a fullerene based hydrogen storage system

    Microsoft Academic Search

    E. L. Brosha; J. R. Davey; F. H. Garzon; S. Gottesfeld

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The project objective was to evaluate hydrogen uptake by fullerene substrates and to probe the potential of the hydrogen\\/fullerene system for hydrogen fuel storage. As part of this project, the authors have completed and tested a fully automated, computer

  2. Fullerene derivatives as electron donor for organic photovoltaic cells

    SciTech Connect

    Zhuang, Taojun; Wang, Xiao-Feng, E-mail: xf-wang@yz.yamagata-u.ac.jp, E-mail: ziruo@yz.yamagata-u.ac.jp; Sano, Takeshi; Kido, Junji [Department of Organic Device Engineering, Graduate School of Engineering, and Research Center for Organic Electronics (ROEL), Yamagata University, Yonezawa 992-8510 (Japan)] [Department of Organic Device Engineering, Graduate School of Engineering, and Research Center for Organic Electronics (ROEL), Yamagata University, Yonezawa 992-8510 (Japan); Hong, Ziruo, E-mail: xf-wang@yz.yamagata-u.ac.jp, E-mail: ziruo@yz.yamagata-u.ac.jp [Department of Organic Device Engineering, Graduate School of Engineering, and Research Center for Organic Electronics (ROEL), Yamagata University, Yonezawa 992-8510 (Japan) [Department of Organic Device Engineering, Graduate School of Engineering, and Research Center for Organic Electronics (ROEL), Yamagata University, Yonezawa 992-8510 (Japan); Department of Materials Science and Engineering, University of California, Los Angeles, California 90095 (United States); Yang, Yang [Department of Materials Science and Engineering, University of California, Los Angeles, California 90095 (United States)] [Department of Materials Science and Engineering, University of California, Los Angeles, California 90095 (United States)

    2013-11-11

    We demonstrated the performance of unconventional, all-fullerene-based, planar heterojunction (PHJ) organic photovoltaic (OPV) cells using fullerene derivatives indene-C{sub 60} bisadduct (ICBA) and phenyl C{sub 61}-butyric acid methyl ester as the electron donors with fullerene C{sub 70} as the electron acceptor. Two different charge generation processes, including charge generation in the fullerene bulk and exciton dissociation at the donor-acceptor interface, have been found to exist in such all-fullerene-based PHJ cells and the contribution to the total photocurrent from each process is strongly dependent on the thickness of fullerene donor. The optimized 5?nm ICBA/40?nm C{sub 70} PHJ cell gives clear external quantum efficiency responses for the long-wavelength photons corresponding to the dissociation of strongly bound Frenkel excitons, which is hardly observed in fullerene-based single layer reference devices. This approach using fullerene as a donor material provides further possibilities for developing high performance OPV cells.

  3. Storage of nuclear materials by encapsulation in fullerenes

    DOEpatents

    Coppa, Nicholas V. (Los Alamos, NM)

    1994-01-01

    A method of encapsulating radioactive materials inside fullerenes for stable long-term storage. Fullerenes provide a safe and efficient means of disposing of nuclear waste which is extremely stable with respect to the environment. After encapsulation, a radioactive ion is essentially chemically isolated from its external environment.

  4. FORMATION OF FULLERENES IN H-CONTAINING PLANETARY NEBULAE

    SciTech Connect

    GarcIa-Hernandez, D. A.; Manchado, A. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, 38200 La Laguna (Spain); GarcIa-Lario, P. [Herschel Science Centre, European Space Astronomy Centre, Research and Scientific Support Department of ESA, Villafranca del Castillo, P.O. Box 50727, E-28080 Madrid (Spain); Stanghellini, L.; Shaw, R. A. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Villaver, E. [Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Szczerba, R. [N. Copernicus Astronomical Center, Rabianska 8, 87-100 Torun (Poland); Perea-Calderon, J. V., E-mail: agarcia@iac.e, E-mail: amt@iac.e, E-mail: Pedro.Garcia-Lario@sciops.esa.in, E-mail: shaw@noao.ed, E-mail: letizia@noao.ed, E-mail: eva.villaver@uam.e, E-mail: szczerba@ncac.torun.p, E-mail: Jose.Perea@sciops.esa.in [European Space Astronomy Centre, INSA S. A., P.O. Box 50727, E-28080 Madrid (Spain)

    2010-11-20

    Hydrogen depleted environments are considered an essential requirement for the formation of fullerenes. The recent detection of C{sub 60} and C{sub 70} fullerenes in what was interpreted as the hydrogen-poor inner region of a post-final helium shell flash planetary nebula (PN) seemed to confirm this picture. Here, we present strong evidence that challenges the current paradigm regarding fullerene formation, showing that it can take place in circumstellar environments containing hydrogen. We report the simultaneous detection of polycyclic aromatic hydrocarbons (PAHs) and fullerenes toward C-rich and H-containing PNe belonging to environments with very different chemical histories such as our own Galaxy and the Small Magellanic Cloud. We suggest that PAHs and fullerenes may be formed by the photochemical processing of hydrogenated amorphous carbon. These observations suggest that modifications may be needed to our current understanding of the chemistry of large organic molecules as well as the chemical processing in space.

  5. Fullerenes Buckminster Fullerenes ("Buckyballs") have fascinated chemists since the original discovery of C60, leading

    E-print Network

    Weston, Ken

    metal ion, such as titanium, zirconium, or uranium directly from carbon vapor. The resulting M@C28 resulting from laser vaporization of a titanium-containing graphite target. Ti@C28 forms as the smallest. Titanium encapsulation offers an attractive route toward synthesis of the smallest fullerenes

  6. Production of Mg and Al Auger electrons by noble gas ion bombardment of Mg and Al surfaces

    NASA Technical Reports Server (NTRS)

    Ferrante, J.; Pepper, S. V.

    1976-01-01

    Relative production efficiencies of Mg and Al Auger electrons by He, Ne, Ar, Kr, and Xe ion bombardment are reported as a function of ion energy for energies not exceeding 3 keV. The experimental apparatus employed consisted of a LEED-Auger system equipped with an ion gun and a four-grid retarding-potential analyzer. It is found that: (1) the shape of the ion-excited Auger signal was independent of the rare gas and quite symmetric; (2) the Al signal was about an order of magnitude smaller than the Mg signal for a given bombarding species and ion-gun voltage; (3) no signal was observed for He(+) bombardment under any of the experimental conditions; (4) signal strengths were independent of temperature and ion dose; (5) the Auger production efficiencies differed by no more than a factor of two among the different gases - except for He(+) - on a given metal; (6) all the signal strengths increased with increasing ion-gun voltage, with no maximum exhibited; and (7) the apparent threshold energy for the Al signal was higher than that for the Mg signal. The differences between the results for the two metals are attributed to the fact that the Al 2p orbital lies deeper in energy and closer to the nucleus than the corresponding Mg orbital.

  7. Excitation of fullerene ions during grazing scattering from a metal surface

    SciTech Connect

    Wethekam, S.; Winter, H. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Brook-Taylor-Strasse 6, D-12489 Berlin (Germany)

    2007-09-15

    Angular distributions, fragmentation, and charge fractions are studied for grazing scattering of C{sub 60}{sup +} fullerenes with keV energies from a clean and flat Al(001) surface. At low energies for the motion along the surface normal, C{sub 60}{sup +} ions are scattered nearly elastically, whereas for larger normal energies energy loss is substantial. We compare our experimental results with classical trajectory simulations exploiting the Tersoff potential between atoms in the cluster and different types of interaction potentials for the cluster with the surface. The internal energy of scattered clusters is deduced from the analysis of fragments. We observe that the loss of kinetic energy for the motion along the surface normal is transferred to internal excitations of the cluster, whereas the energy transfer to the metal surface is negligible. The charge state distributions for scattered projectiles can be understood by a full neutralization of incident ions at the surface and subsequent delayed electron emission.

  8. Fullerene fine particles adhere to pollen grains and affect their autofluorescence and germination

    PubMed Central

    Aoyagi, Hideki; Ugwu, Charles U

    2011-01-01

    Adhesion of commercially produced fullerene fine particles to Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica pollen grains was investigated. The autofluorescence of pollen grains was affected by the adhesion of fullerene fine particles to the pollen grains. The degree of adhesion of fullerene fine particles to the pollen grains varied depending on the type of fullerene. Furthermore, germination of Camellia japonica pollen grains was inhibited by the adhesion of fullerene fine particles. PMID:24198486

  9. Cesium Ion Bombardment of Metal Surfaces

    NASA Astrophysics Data System (ADS)

    Tompa, Gary S.

    The steady state cesium coverage due to cesium ion bombardment of molybdenum and tungsten has been studied for the incident energy range below 500 eV. When a sample is exposed to a positive cesium ion beam, the work function decreases until steady state is reached with a total dose of less than (DBLTURN)1*10('16) ions/cm('2), for both tungsten and molybdenum. A steady state minimum work function surface is produced at an incident energy of (DBLTURN)100 eV for molybdenum and at an incident energy of (DBLTURN)45 eV for tungsten. Increasing the incident energy results in an increase in the work function corresponding to a decrease in the surface coverage of cesium. At incident energies less than that giving the minimum work function, the work function approaches that of cesium metal. At a given bombarding energy the cesium coverage of tungsten is uniformly less than that of molybdenum. The effects of hydrogen gas coadsorption have also been examined. Hydrogen coadsorption does not have a large effect on the steady state work functions. The largest shifts in the work function due to the coadsorption of hydrogen occur on the samples when there is no cesium present. A theory describing the steady state coverage has been developed and is used to make predictions for other materials. A simple sticking and sputtering relationship, not including implantation, cannot account for the steady state coverage. At low concentrations, cesium coverage of a target is proportional to the ratio of (1-(beta))/(gamma) where (beta) is the reflection coefficient and (gamma) is the sputter yield. High coverages are produced on molybdenum due to implantation and low backscattering, because molybdenum is lighter than cesium. For tungsten the high backscattering and low implantation result in low coverages. The implications of these results for negative hydrogen surface conversion sources are clear, molybdenum is a better material than tungsten since a much lower work function surface is maintained on molybdenum at converter operating energies.

  10. Determination of fullerene scattering length density: a critical parameter for understanding the fullerene distribution in bulk heterojunction organic photovoltaic devices.

    PubMed

    Clulow, Andrew J; Armin, Ardalan; Lee, Kwan H; Pandey, Ajay K; Tao, Chen; Velusamy, Marappan; James, Michael; Nelson, Andrew; Burn, Paul L; Gentle, Ian R; Meredith, Paul

    2014-02-11

    Fullerene derivatives are commonly used as electron acceptors in combination with (macro)molecular electron donors in bulk heterojunction (BHJ) organic photovoltaic (OPV) devices. Understanding the BHJ structure at different electron donor/acceptor ratios is critical to the continued improvement and development of OPVs. The high neutron scattering length densities (SLDs) of the fullerenes provide effective contrast for probing the distribution of the fullerene within the blend in a nondestructive way. However, recent neutron scattering studies on BHJ films have reported a wide range of SLDs ((3.6-4.4) × 10(-6) Å(-2)) for the fullerenes 60-PCBM and 70-PCBM, leading to differing interpretations of their distribution in thin films. In this article, we describe an approach for determining more precisely the scattering length densities of the fullerenes within a polymer matrix in order to accurately quantify their distribution within the active layers of OPV devices by neutron scattering techniques. PMID:24467334

  11. The effect of fullerenes and functionalized fullerenes on Daphnia magna phototaxis and swimming behavior.

    PubMed

    Brausch, Kathryn A; Anderson, Todd A; Smith, Philip N; Maul, Jonathan D

    2011-04-01

    The effects of carbon fullerenes (C(60) ) on the environment is a growing concern as the use of nanotechnology continues to increase. Previous studies have reported alteration in Daphnia magna behavior, including increased hopping frequency, heart rate, and appendage movement in response to tetrahydrofuran-solubilized C(60) and increased hopping rate and appendage movement in response to tetrahydrofuran-solubilized C(60) HxC(70) Hx exposure. The objective of the current study was to evaluate effects of water-stirred C(60) and sonicated carboxylic acid functionalized fullerenes (fC(60) ) on D. magna behavior. Behavioral endpoints are important because changes in behavior can influence predator avoidance behaviors, alter predation risk, and potentially lead to population-level effects in D. magna. To evaluate the potential effect of fullerenes on phototactic behavior, D. magna were exposed to 545.4?µg/L C(60) and 545.6?µg/L fC(60) , and vertical position was monitored. Daphnia magna were also exposed to 545.4?µg/L C(60) , 545.6?µg/L fC(60) , and 829.3?µg/L fC(60) , and swimming movements were recorded. Fullerenes altered the vertical migration response of D. magna to the addition of food, but D. magna vertical position response to predator cues was similar for fullerenes and controls. In addition, D. magna reduced swimming speed when exposed to C(60) , but other components of D. magna swimming behavior were not affected. This research supports previous findings and suggests that C(60) may influence D. magna behavior and highlights the need for further research on sublethal behavioral modifications in aquatic organisms in response to nanomaterials. PMID:21184527

  12. Leak decay method of helium bombardment leak testing

    NASA Technical Reports Server (NTRS)

    Garton, W. P.

    1972-01-01

    Method for verifying hermetic seal quality of small components is described. Procedure for using helium bombardment and examination with mass spectrometer is described. Technique eliminates errors in seal quality determination and checks quality of seals without contaminating products.

  13. Computer simulation of the single crystal surface modification and analysis at grazing low-energy ion bombardment

    NASA Astrophysics Data System (ADS)

    Umarov, F. F.; Dzhurakhalov, A. A.; Mukashev, K. M.

    2015-04-01

    The specific peculiarities of 0.5-10 keV Ne+, Ar+, Kr+, Be+ and Se+ ions scattering, sputtering and implantation processes at grazing ion bombardment of GaAs (001), Si(001), SiC(001) and Cu(100) surfaces and their possible application for the surface modification and analysis have been studied by computer simulation. Sputtering yields in the primary knock-on recoil atoms reghne versus the initial energy of incident ions (E0 = 0.5-5 keV) and angle of incidence (? = 0-30°) counted from a target surface have been calculated. The colliding particles mass ratio influence on the energy losses of scattering particles, sputtering yields and near-surface depth distributions of implanted particles is established, ft was shown that in the case of grazing ion bombardment the layer-by-layer sputtering is possible and its optimum are observed within the small angle range of the glancing angles near the threshold sputtering angle. Comparative studies of layer-by-layer sputtering for Si(001) and SiC(001) surfaces versus the initial energy of incident ions as well as an effective sputtering and sputtering threshold are discussed.

  14. Direct solid-phase hydrogenation of fullerenes

    Microsoft Academic Search

    Changming Jin; Robert Hettich; Robert Compton; David Joyce; James Blencoe; Timothy Burch

    1994-01-01

    Direct hydrogenation of C[sub 60] and C[sub 70] was achieved without the use of a catalyst by exposing solid-phase fullerenes to high-pressure hydrogen gas (500-850 bar) at temperatures ranging from 573 to 623 K. Efficient production of C[sub 60]H[sub x](x = 2-18) and C[sub 70]H[sub y] (y = 4-30) was identified by laser desorption Fourier transform mass spectrometry. Temperatures above

  15. Possible mechanisms of fullerene C?? antioxidant action.

    PubMed

    Chistyakov, V A; Smirnova, Yu O; Prazdnova, E V; Soldatov, A V

    2013-01-01

    Novel mechanism of antioxidant activity of buckminsterfullerene C?? based on protons absorbing and mild uncoupling of mitochondrial respiration and phosphorylation was postulated. In the present study we confirm this hypothesis using computer modeling based on Density Functional Theory. Fullerene's geroprotective activity is sufficiently higher than those of the most powerful reactive oxygen species scavengers. We propose here that C?? has an ability to acquire positive charge by absorbing inside several protons and this complex could penetrate into mitochondria. Such a process allows for mild uncoupling of respiration and phosphorylation. This, in turn, leads to the decrease in ROS production. PMID:24222918

  16. Enhanced optical limiting in derivatized fullerenes

    NASA Astrophysics Data System (ADS)

    Smilowitz, L.; McBranch, D.; Klimov, V.; Robinson, J. M.; Koskelo, A.; Grigorova, M.; Mattes, B. R.; Wang, H.; Wudl, F.

    1996-07-01

    We have observed enhanced optical limiting behavior in solutions of a derivatized fullerene (phenyl-C61-butyric acid cholesteryl ester) from 532 to 700 nm. Transient absorption measurements determined the spectral and temporal regions of interest for optical limiting in C60 and in C 60 derivatives that are due to a reverse saturable absorption mechanism and predicted enhanced limiting at longer wavelengths. Intensity-dependent transmission measurements made at several wavelengths confirmed these results. The increased solubility and the broadened ground-state absorption of the functionalized C60 make it suitable for use as an optical limiter in the red and the near infrared.

  17. Oxygen intake in ion irradiated fullerene films

    NASA Astrophysics Data System (ADS)

    Kumar, Amit; Khan, S. A.; Kumar, Manvendra; Agarwal, D. C.; Singh, Fouran; Tripathi, A.; Govind; Shivaprasad, S. M.; Salomon, J.; Pichon, L.; Pivin, J. C.; Avasthi, D. K.

    2008-04-01

    The present work reports the change in the oxygen content in energetic ion irradiated fullerene films. The oxygen contents in irradiated films have been studied using on-line elastic recoil detection analysis (ERDA) and off-line X-ray photo electron emission (XPS) and nuclear reaction analysis (NRA) techniques. The XPS and NRA techniques show that the oxygen content increases with ion fluence, whereas on-line ERDA measurements reveal that the oxygen content decreases with ion fluence. These experiments give clear evidence that oxygen content in irradiated films increases after exposure to the atmospheric oxygen.

  18. Process for the removal of impurities from combustion fullerenes

    DOEpatents

    Alford, J. Michael; Bolskar, Robert

    2005-08-02

    The invention generally relates to purification of carbon nanomaterials, particularly fullerenes, by removal of PAHs and other hydrocarbon impurities. The inventive process involves extracting a sample containing carbon nanomaterials with a solvent in which the PAHs are substantially soluble but in which the carbon nanomaterials are not substantially soluble. The sample can be repeatedly or continuously extracted with one or more solvents to remove a greater amount of impurities. Preferred solvents include ethanol, diethyl ether, and acetone. The invention also provides a process for efficiently separating solvent extractable fullerenes from samples containing fullerenes and PAHs wherein the sample is extracted with a solvent in which both fullerenes and PAHs are substantially soluble and the sample extract then undergoes selective extraction to remove PAHs. Suitable solvents in which both fullerenes and PAHs are soluble include o-xylene, toluene, and o-dichlorobenzene. The purification process is capable of treating quantities of combustion soot in excess of one kilogram and can produce fullerenes or fullerenic soot of suitable purity for many applications.

  19. Diffuse Interstellar Bands in (Proto-) Fullerene-Rich Environments

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.

    2014-02-01

    The recent infrared detection of fullerenes (C60 and C70) in Planetary Nebulae (PNe) and R Coronae Borealis (RCB) stars offers a beautiful opportunity for studying the diffuse interstellar bands (DIBs) in sources where fullerenes are abundant. Here we present for the first time a detailed inspection of the optical spectra of the hot RCB star DY Cen and two fullerene PNe (Tc 1 and M 1-20), which permits us to directly explore the fullerenes - DIB connection. The DIB spectrum of DY Cen (García-Hernández et al. 2012a) is remarkably different from that in fullerene PNe (García-Hernández & Díaz-Luis 2013). In particular, Tc 1 displays unusually strong 4428 Å and 6309 Å DIBs, which are normal (or not seen) in DY Cen. On the other hand, DY Cen displays an unusually strong 6284 Å DIB that is found to be normal in fullerene PNe. We also report the detection of new broad and unidentified features centered at 4000 Å and 6525 Å in DY Cen and Tc 1, respectively. We suggest that the new 4000 Å band seen in DY Cen may be related to the circumstellar proto-fullerenes seen at infrared wavelengths (García-Hernández et al. 2012a). However, the intense 4428 Å DIB (probably also the 6309 Å DIB and the new 6525 Å band) may be related to the presence of larger fullerenes (e.g., C80, C240, C320, and C540) and buckyonions (multishell fullerenes such as C60@C240 and C60@C240@C540) in the circumstellar envelope of Tc 1 (García-Hernández & Díaz-Luis 2013).

  20. Raman scattering and hydrogen-content analysis of amorphous hydrogenated carbon films irradiated with 200keV C sup + ions

    Microsoft Academic Search

    Leonilda A. Far-row; Barry J. Wilkens; Antoni S. Gozdz; Derrick L. Hart

    1990-01-01

    Amorphous hydrogenated diamondlike'' carbon films ({ital a}-C:H) have been modified by bombardment with 200-keV C{sup +} ions at four doses ranging from 10¹⁴ to 10¹⁷ cm⁻². Ratios of carbon to hydrogen in the resulting samples have been determined with use of elastic recoil detection (ERD) and Rutherford backscattering (RBS); hydrogen content is significantly reduced as the dose is increased. Raman

  1. Structural investigation of keV Ar-ion-induced surface ripples in Si by cross-sectional transmission electron microscopy

    E-print Network

    Nordlund, Kai

    O2, Ge, and GaAs, though rippling has been been observed recently in metals Ag and Cu as well.4 Amorphization of Si Refs. 15,16 by heavy ion such as Ar bombardment at keV energies occurs in a dose range 1014 have to be the same everywhere. This is a very relevant question be- cause quite recently ion-enhanced

  2. Fullerene synthesis by laser pyrolysis of hydrocarbons

    NASA Astrophysics Data System (ADS)

    Armand, X.; Herlin, N.; Voicu, I.; Cauchetier, M.

    1997-11-01

    A novel route for the synthesis of carbon soots containing fullerenes has been developed i.e. the pyrolysis of hydrocarbons in gas, vapour or aerosol phase, which are heated and decomposed through the absorption of IR photons emitted by a high power CW CO2 laser. Hydrocarbons such as benzene (+ cyclopentadiene), acetylene or ethylene have been tested, pure or mixed with an oxidizer agent (nitrous oxide or oxygen) and/or a sensitizer (sulfur hexafluoride). The fullerenes were identified in the soots obtained by using as precursor the benzene/oxygen or acetylene/oxygen mixture. When these compounds are produced in significant amounts they can be detected directly in the as-formed soots by Fourier Transform Infrared Spectroscopy (FTIR). For small quantities, a Soxhlet extraction procedure is necessary and the extracts are characterized by FTIR and by other methods which are more sensitive, like mass spectrometry or High Performance Liquid Chromatography (HPLC) coupled with ultraviolet-visible spectroscopy. The influence of the operating conditions is discussed.

  3. Interaction of C(60) fullerene with lipids.

    PubMed

    Cataldo, Franco

    2010-06-01

    Unsaturated lipids when exposed to air at room temperature undergo a slow autoxidation. When fullerene C(60) was dissolved in selected lipids (ethyl oleate, ethyl linoleate, linseed oil and castor oil) the spectrophotometric analysis shows that the oxidation is concentrated to C(60) which is converted to an epoxide C(60)O. Thus, fullerene C(60) displays antioxidant activity not only when dissolved in unsaturated lipids but also, more generally, when dissolved in unsaturated solvents subjected to autoxidation like, for example, in cyclohexene. The behaviour of C(60) in ethyl oleate has been compared with that of the known antioxidant TMPPD (N,N',N,N,'-tetramethyl-p-phenylenediamine) in ethyl oleate. The mechanism of the antioxidant action of C(60) in lipids has been proposed. The kinetics of C(60) oxidation in lipids was determined spectrophotometrically both at room temperature in the dark and under UV irradiation. The oxidized products derived from C(60) photo-oxidation in lipids have been identified. PMID:20338159

  4. Feasibility of fullerene waste as carbonaceous adsorbent

    SciTech Connect

    Cleveland, T.G.; Garg, S.; Rixey, W.G. [Univ. of Houston, TX (United States). Dept. of Civil and Environmental Engineering

    1996-03-01

    This note investigates using the waste soot generated in fullerene manufacture as an adsorbent. Both oven-dried and air-activated samples of waste soot are compared with three commercially available powdered activated carbons (PACs): Nuchar-SA, HDH, and Calgon-RC. Three model compounds were chosen for adsorption tests--TCE, Benzene, and Phenol--representing a small branched molecule, a small nonpolar ring molecule, and relatively polar ring molecule. Additionally, the effectiveness of total organic carbon (TOC) removal from wastewater was evaluated. Oven-dried soot performed poorly as compared to the commercial carbons, but activation of the waste soot for 60 min at 450 C in air resulted in an activated carbon (aFWS) with properties similar to those of commercially available PACs. The aFWS performed better than one would predict from the typical characterization measures of iodine number, molasses number, and methylene blue number. The data for phenol suggest some functional groups are created during the activation of the waste soot. These results show that large-scale fullerene manufacturing can be a zero-waste industry, because its primary waste product can be converted into a useful material.

  5. Fullerene and the origin of life.

    PubMed

    Goodman, Geoffrey; Gershwin, M Eric; Bercovich, Dani

    2012-10-01

    The role of carbon in the development of life and as the structural backbone of all organisms is universally accepted and an essential part of evolution. However, the molecular basis is largely unknown and the interactions of carbon with nitrogen and oxygen in space are enigmatic. In 1985, the previously unknown form of carbon, coined fullerene, was discovered. We hypothesize that by virtue of the unique properties of fullerene, this hollow, ultra-robust, large, purely carbon molecule was the earliest progenitor of life. It acted as a stable universal biologic template on which small molecules spontaneously assembled and then formed, by further assembly, a surface mantle (here termed rosasome) of larger molecules. We submit that this process, by its inherent flexibility, initiated evolution, allowing the emergence of parallel diverse rosasome lines responding selectively to varying spatial environments. For example, rosasomal lines mantled with nucleotide and peptide layers are conceived as primordial forerunners of the ubiquitous ribosome. Moreover, the parallel independent and interdependent evolution of rosasome lines would be more rapid than sequential development, refute precedence of either DNA or RNA, and explain the evolution of integration of two subunits with different structures and functions in ribosomes and of the triplet nature of the codon. Based on recent astronomical data, this hypothesis supports the concept that life is not a singularity. This concept also suggests a potential vehicle for therapeutics, biotechnology and genetic engineering. PMID:23193780

  6. Synthesis of [60]fullerene acetals and ketals: reaction of [60]fullerene with aldehydes/ketones and alkoxides.

    PubMed

    Wang, Guan-Wu; Li, Fa-Bao; Chen, Zhong-Xiu; Wu, Ping; Cheng, Bin; Xu, Yu

    2007-06-22

    The reaction of C(60) with propionaldehyde (butyraldehyde or phenylacetaldehyde) and MeONa-MeOH or EtONa-EtOH in anhydrous chlorobenzene in the presence of air at room temperature unexpectedly gave rare fullerene acetals 2aa-cb, while the reaction of C(60) with acetone (acetophenone, cyclohexanone, or cyclopentanone) and MeONa-MeOH or EtONa-EtOH under the same conditions afforded the uncommon fullerene ketals 4aa-db. A possible reaction mechanism for the formation of the fullerene acetals and ketals is proposed based on further experimental results. PMID:17523665

  7. Phase equilibria in the fullerene C 60 -fullerene C 70 -hexane- o -xylene-dimethylformamide system

    Microsoft Academic Search

    V. A. Keskinov; A. K. Pyartman; N. A. Charykov; O. V. Arapov; A. A. Pronkin; V. V. Lishchuk; V. V. Leonov

    2008-01-01

    The phase diagram of the hexane-o-xylene-dimethylformamide ternary liquid system was studied at T = 298.15 K. The diagram contained the regions of homogeneous solutions and two-phase liquid systems (systems with stratification),\\u000a phase I being enriched in dimethylformamide and phase II, in hexane. The distribution of fullerenes C60 and C70 was considered at various concentrations and simultaneous presence in sections at

  8. Phase equilibria in the fullerene C60-fullerene C70-hexane- o-xylene-dimethylformamide system

    Microsoft Academic Search

    V. A. Keskinov; A. K. Pyartman; N. A. Charykov; O. V. Arapov; A. A. Pronkin; V. V. Lishchuk; V. V. Leonov

    2008-01-01

    The phase diagram of the hexane- o-xylene-dimethylformamide ternary liquid system was studied at T = 298.15 K. The diagram contained the regions of homogeneous solutions and two-phase liquid systems (systems with stratification), phase I being enriched in dimethylformamide and phase II, in hexane. The distribution of fullerenes C60 and C70 was considered at various concentrations and simultaneous presence in sections

  9. Simple and Onion-type Fullerenes shells as resonators and amplifiers

    E-print Network

    Amusia, M Ya

    2009-01-01

    We discuss the influence of a single or double fullerenes shell upon photoionization and vacancy decay of an atom, stuffed inside the fullerenes construction. The main manifestations of this influence are additional structures in the photoionization cross-section and variation of the vacancy decay probability. The main mechanisms, with which fullerenes shells affect the processes in caged atoms is the scattering of the outgoing electrons by the fullerenes shell and modification of the photon beam due to fullerenes shell polarization. General consideration will be illustrated by numeric calculations where C60 and C240 will be chosen as fullerenes and Ar and Xe as caged atoms.

  10. Antibacterial Activity of Fullerene Water Suspensions: Effects of

    E-print Network

    Alvarez, Pedro J.

    Antibacterial Activity of Fullerene Water Suspensions: Effects of Preparation Method and Particle and tested for antibacterial activity using Bacillus subtilis as a test organism. All suspensions exhibited relatively strong antibacterial activity. Fractions containing smaller aggregates had greater antibacterial

  11. Production and Consumption of Reactive Oxygen Species by Fullerenes

    EPA Science Inventory

    Reactive oxygen species (ROS) are one of the most important intermediates in chemical, photochemical, and biological processes. To understand the environmental exposure and toxicity of fullerenes better, the production and consumption of ROS (singlet oxygen, superoxide, hydrogen ...

  12. Hydrogen storage in fullerenes and in an organic hydride

    SciTech Connect

    Wang, J.C.; Murphy, R.W.; Chen, F.C. [Oak Ridge National Lab., TN (United States). Energy Div.; Loutfy, R.O.; Veksler, E.; Li, W. [Materials and Electrochemical Research Corp., Tucson, AZ (United States)

    1998-05-29

    While the authors have demonstrated the importance and usefulness of thermal management to the hydrogen storage in fullerenes, their recent effort has concentrated on materials improvement and physical model development. In this paper, they report the results of this effort as follows: (1) Liquid phase hydrogenation of fullerenes indicated that more than 6 wt% capacity can be obtained at 180 C, 350--400 psi; (2) Dehydrogenation of fullerenes hydrides below 225 C was demonstrated using an Ir-based P-C-P pincer complex catalyst; (3) Cyclic hydrogenation and dehydrogenation tests of an organic hydride at 7 wt% capacity were conducted at 180--260 C; and (4) Physical models developed for fullerenes were determined to be applicable to this organic hydride (with much smaller activation energies).

  13. Particle bombardment effects on thin-film deposition: A review

    SciTech Connect

    Mattox, D.M.

    1989-05-01

    In many atomistic film deposition processes, concurrent energetic particle bombardment (ions, atoms, molecules, atom clusters) may occur inadvertently and uncontrollably or bombardment may be used to deliberately modify film properties. These energetic particles can arise from (i) the acceleration of charged particles, (ii) high-energy neutrals from reflection from bombarded surfaces, or (iii) charge exchange processes. Particle bombardment effects that can affect film formation and growth include (a) modifying the substrate surface (cleaning, defect formation), (b) momentum transfer processes in the surface region (sputtering, desorption, recoil implantation, defect formation), (c) addition of heat to the surface region, and (d) formation of secondary elelctrons that can affect chemical reactions. These in turn affect film properties such as adhesion, residual film stress, film morphology, density, grain size and orientation, surface coverage, pinhole density, and surface area. The understanding of these effects and how to use them advantageously is important to those utilizing processes where concurrent energetic particle bombardment is occurring or can be made to occur.

  14. Morphology of polymer\\/fullerene bulk heterojunction solar cells

    Microsoft Academic Search

    Harald Hoppe; Niyazi Serdar Sariciftci

    2006-01-01

    Within the different organic photovoltaic devices the conjugated polymer\\/fullerene bulk heterojunction approach is one of the foci of today's research interest. These devices are highly dependent on the solid state nanoscale morphology of the two components (donor\\/acceptor) in the photoactive layer. The need for finely phase separated polymer-fullerene blends is expressed by the limited exciton diffusion length present in organic

  15. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    DOEpatents

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  16. Pharmacokinetics of a Water-Soluble Fullerene in Rats

    Microsoft Academic Search

    PRABHU RAJAGOPALAN; FRED WUDL; RAYMOND F. SCHINAZI; DOUGLAS BOUDINOT

    1996-01-01

    Fullerenes are the recently discovered third allotropic form of carbon. The biological activities of these compounds are being studied for various purposes. The bis(monosuccinimide) derivative ofp,p*-bis(2-amino- ethyl)-diphenyl-C60 (MSAD-C60) is a water-soluble fullerene derivative. MSAD-C60 has been shown to have antiviral activity against human immunodeficiency virus types 1 and 2 in vitro and to have virucidal and anti-human immunodeficiency virus protease

  17. Fullerenes and interplanetary dust at the Permian-Triassic boundary.

    PubMed

    Poreda, Robert J; Becker, Luann

    2003-01-01

    We recently presented new evidence that an impact occurred approximately 250 million years ago at the Permian-Triassic boundary (PTB), triggering the most severe mass extinction in the history of life on Earth. We used a new extraterrestrial tracer, fullerene, a third carbon carrier of noble gases besides diamond and graphite. By exploiting the unique properties of this molecule to trap noble gases inside of its caged structure (helium, neon, argon), the origin of the fullerenes can be determined. Here, we present new evidence for fullerenes with extraterrestrial noble gases in the PTB at Graphite Peak, Antarctica, similar to PTB fullerenes from Meishan, China and Sasayama, Japan. In addition, we isolated a (3)He-rich magnetic carrier phase in three fractions from the Graphite Peak section. The noble gases in this magnetic fraction were similar to zero-age deep-sea interplanetary dust particles (IDPs) and some magnetic grains isolated from the Cretaceous-Tertiary boundary. The helium and neon isotopic compositions for both the bulk Graphite Peak sediments and an isolated magnetic fraction from the bulk material are consistent with solar-type gases measured in zero-age deep-sea sediments and point to a common source, namely, the flux of IDPs to the Earth's surface. In this instance, the IDP noble gas signature for the bulk sediment can be uniquely decoupled from fullerene, demonstrating that two separate tracers are present (direct flux of IDPs for (3)He vs. giant impact for fullerene). PMID:12804366

  18. Histopathology of fathead minnow (Pimephales promelas) exposed to hydroxylated fullerenes.

    PubMed

    Jovanovi?, Boris; Whitley, Elizabeth M; Pali?, Dušan

    2014-11-01

    Hydroxylated fullerenes are reported to be very strong antioxidants, acting to quench reactive oxygen species, thus having strong potential for important and widespread applications in innovative therapies for a variety of disease processes. However, their potential for toxicological side effects is still largely controversial and unknown. Effects of hydroxylated fullerenes C60(OH)24 on the fathead minnow (Pimephales promelas) were investigated microscopically after a 72-hour (acute) exposure by intraperitoneal injection of 20 ppm of hydroxylated fullerenes per gram of body mass. Cumulative, semi-quantitative histopathologic evaluation of brain, liver, anterior kidney, posterior kidney, skin, coelom, gills and the vestibuloauditory system revealed significant differences between control and hydroxylated fullerene-treated fish. Fullerene-treated fish had much higher cumulative histopathology scores. Histopathologic changes included loss of cellularity in the interstitium of the kidney, a primary site of haematopoiesis in fish, and loss of intracytoplasmic glycogen in liver. In the coelom, variable numbers of leukocytes, including many macrophages and fewer heterophils and rodlet cells, were admixed with the nanomaterial. These findings raise concern about in vivo administration of hydroxylated fullerenes in experimental drugs and procedures in human medicine, and should be investigated in more detail. PMID:23883179

  19. Implications of fullerene-60 upon in-vitro LDPE biodegradation.

    PubMed

    Sah, Aditi; Kapri, Anil; Zaidi, M G H; Negi, Harshita; Goel, Reeta

    2010-05-01

    Fullerene-60 nanoparticles were used for studying their influence upon the LDPE biodegradation efficiency of two potential polymer-degrading consortia comprising of three bacterial strains each. At a concentration of 0.01% (w/v) in minimal broth lacking dextrose, fullerene did not have any negative influence upon the consortial growth. However, fullerene was found to be detrimental for bacterial growth at higher concentrations (viz. 0.25%, 0.5% and 1%). Although, addition of 0.01% fullerene into the biodegradation assays containing 5 mg/ml LDPE subsided growth-curves significantly, but subsequent analysis of degraded products revealed enhanced biodegradation. Fourier transform infrared spectroscopy (FT-IR) revealed breakage and formation of chemical bonds along with introduction of nu C-O frequencies into hydrocarbon backbone of LDPE. Further, simultaneous thermogravimetric-differential thermogravimetry-differential thermal analysis (TG-DTG-DTA) revealed higher number of decomposition steps along with a 1,000-fold decrease in the heat of reactions (DeltaH) in fullerene-assisted biodegraded LDPE suggesting probable formation of multiple, macromolecular by-products. This is the first report whereby fullerene-60, which is otherwise considered toxic, has helped to alleviate polymer biodegradation process of bacterial consortia. PMID:20519915

  20. Effects of Two Fullerene Derivatives on Monocytes and Macrophages

    PubMed Central

    Pacor, Sabrina; Grillo, Alberto; ?or?evi?, Luka; Zorzet, Sonia; Da Ros, Tatiana; Prato, Maurizio

    2015-01-01

    Two fullerene derivatives (fullerenes 1 and 2), bearing a hydrophilic chain on the pyrrolidinic nitrogen, were developed with the aim to deliver anticancer agents to solid tumors. These two compounds showed a significantly different behaviour on human neoplastic cell lines in vitro in respect to healthy leukocytes. In particular, the pyrrolidinium ring on the fullerene carbon cage brings to a more active compound. In the present work, we describe the effects of these fullerenes on primary cultures of human monocytes and macrophages, two kinds of immune cells representing the first line of defence in the immune response to foreign materials. These compounds are not recognized by circulating monocytes while they get into macrophages. The evaluation of the pronecrotic or proapoptotic effects, analysed by means of analysis of the purinergic receptor P2X7 activation and of ROS scavenging activity, has allowed us to show that fullerene 2, but not its analogue fullerene 1, displays toxicity, even though at concentrations higher than those shown to be active on neoplastic cells. PMID:26090460

  1. A high resolution water soluble fullerene molecular resist for electron beam lithography.

    PubMed

    Chen, X; Palmer, R E; Robinson, A P G

    2008-07-01

    Traditionally, many lithography resists have used hazardous, environmentally damaging or flammable chemicals as casting solvent and developer. There is now a strong drive towards processes that are safer and more environmentally friendly. We report nanometre-scale patterning of a fullerene molecular resist film with electron beam lithography, using water as casting solvent and developer. Negative tone behaviour is demonstrated after exposure and development. The sensitivity of this resist to 20 keV electrons is 1.5 × 10(-2) C cm(-2). Arrays of lines with a width of 30-35 nm and pitches of 200 and 400 nm, and arrays of dots with a diameter of 40 nm and a pitch of 200 nm have been patterned at 30 keV. The etch durability of this resist was found to be ?2 times that of a standard novolac based resist. Initial results of the chemical amplification of this material for enhanced sensitivity are also presented. PMID:21828704

  2. Topographic and crystallographic characterization of a grazing-ion-bombarded GaAs(110) surface by time-of-flight ion-scattering spectrometry

    SciTech Connect

    Gayone, J.E.; Pregliasco, R.G.; Gomez, G.R.; Sanchez, E.A.; Grizzi, O. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8400 San Carlos de Bariloche, Rio Negro (Argentina)] [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Consejo Nacional de Investigaciones Cientificas y Tecnicas, 8400 San Carlos de Bariloche, Rio Negro (Argentina)

    1997-08-01

    We studied the topography and the atomic structure of a clean GaAs(110) surface by time-of-flight ion-scattering spectrometry (TOF-ISS). In a first series of measurements the surface was cleaned by standard cycles of ion bombardment and annealing (500 eV Ar{sup +}, 500{degree}C). This method was very efficient to remove surface contaminants but not to smooth out the damage produced in TOF-ISS experiments. A cleaning method consisting of grazing bombardment with 20 keV Ar{sup +} combined with annealing at 500{degree}C resulted in a clear improvement of the surface flatness. This was confirmed by measurements of electron energy distributions recorded under grazing proton bombardment and by a topographical analysis with an atomic force microscope. The crystallographic structure of the grazing ion bombarded surface was then studied by TOF-ISS. The quasisingle backscattered intensity measured for 5 keV Ne{sup +} presented strong variations with the incident and azimuthal angles which are consistent with the generally accepted relaxed GaAs(110) surface. From the comparison of critical angles measured and focusing regions calculated with a code recently developed we have obtained an As-Ga first interlayer spacing {Delta}Z=(0.66{plus_minus}0.08){Angstrom}, and the spacings between the first and second As layers {Delta}Z{sub 1,2}{sup As}=(2.25{plus_minus}0.08) {Angstrom} and between the first and second Ga layers {Delta}Z{sub 1,2}{sup Ga}=(1.57{plus_minus}0.1) {Angstrom}. {copyright} {ital 1997} {ital The American Physical Society}

  3. Fullerene Embedded Shape Memory Nanolens Array

    NASA Astrophysics Data System (ADS)

    Jeon, Sohee; Jang, Jun Young; Youn, Jae Ryoun; Jeong, Jun-Ho; Brenner, Howard; Song, Young Seok

    2013-11-01

    Securing fragile nanostructures against external impact is indispensable for offering sufficiently long lifetime in service to nanoengineering products, especially when coming in contact with other substances. Indeed, this problem still remains a challenging task, which may be resolved with the help of smart materials such as shape memory and self-healing materials. Here, we demonstrate a shape memory nanostructure that can recover its shape by absorbing electromagnetic energy. Fullerenes were embedded into the fabricated nanolens array. Beside the energy absorption, such addition enables a remarkable enhancement in mechanical properties of shape memory polymer. The shape memory nanolens was numerically modeled to impart more in-depth understanding on the physics regarding shape recovery behavior of the fabricated nanolens. We anticipate that our strategy of combining the shape memory property with the microwave irradiation feature can provide a new pathway for nanostructured systems able to ensure a long-term durability.

  4. Electron bombardment propulsion system characteristics for large space systems

    NASA Technical Reports Server (NTRS)

    Byers, D. C.; Rawlin, V. K.

    1976-01-01

    The results of an anlaysis of electron bombardment ion propulsion systems for use in the transportation and on-orbit operations of large space systems are presented. Using baseline technology from the ongoing primary propulsion program and other sources, preliminary estimates of the expected characteristics of key system elements such as thrusters and propellant storage systems were performed. Projections of expected thruster performance on argon are presented based on identified constraints which limit the achievable thrust and/or power density of bombardment thrusters. System characteristics are then evaluated as a function of thruster diameter and specific impulse.

  5. Changes in Agglomeration of Fullerenes During Ingestion and Excretion in Thamnocephalus Platuyrus

    EPA Science Inventory

    The crustacean Thamnocephalus platyurus was exposed to aqueous suspensions of fullerenes C60 and C70. Aqueous fullerene suspensions were formed by stirring C60 and C70 as received from a commercial vendor in deionized water (term...

  6. Synthesis of novel fullerene-functionalized polysulfones for optical limiting applications

    Microsoft Academic Search

    Annamaria Celli; Paola Marchese; Micaela Vannini; Corrado Berti; Ilaria Fortunati; Raffaella Signorini; Renato Bozio

    2011-01-01

    High-performance materials in the optical field, with special reference to optical limiting applications, can be obtained by combining nonlinear optical (NLO) active molecules with high optical quality hosts. An interesting method is the synthesis of fullerene–polymer systems. In this paper novel fullerene–polysulfone samples were obtained by direct fullerenation between a commercial sample of polysulfone and fullerene, using electrophilic aromatic substitution

  7. Effects of 70-keV electrons on two polyarylene ether ketones

    NASA Technical Reports Server (NTRS)

    Kingsbury, Kevin B.; Hawkins, Douglas S.; Orwoll, Robert A.; Kiefer, Richard L.; Long, Sheila A. T.

    1989-01-01

    Films prepared from two polyarylene ether ketones with the repeat units -PhC(O)PhC(O)-PhOPhXPhO- where X = C(CH3)2 or CH2 and Ph = C6H4, were bombarded with 70-keV electrons. The effects of irradiation were determined from the fraction of gel formed; the intrinsic viscosities, gel permeation chromatography, and NMR spectroscopy of the soluble portion of the irradiated films; and the changes in the IR spectra of the materials. In a Charlesby-Pinner analysis of the gel fractions of the polyarylene ether ketone with the isopropylidene group, the numbers of scission and cross-linking events per 100 eV (9649 kJ/mol) absorbed were found to be small with G(S) = 0.002 and G(X) = 0.009, respectively.

  8. The development of a fullerene based hydrogen storage system

    SciTech Connect

    Brosha, E.L.; Davey, J.R.; Garzon, F.H.; Gottesfeld, S.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The project objective was to evaluate hydrogen uptake by fullerene substrates and to probe the potential of the hydrogen/fullerene system for hydrogen fuel storage. As part of this project, the authors have completed and tested a fully automated, computer controlled system for measuring hydrogen uptake that is capable of handling both a vacuum of 1 x 10{sup -6} torr and pressures greater than 200 bars. The authors have first established conditions for significant uptake of hydrogen by fullerenes. Subsequently, hydrogenation and dehydrogenation of pure and catalyst-doped C60 was further studied to probe suitability for hydrogen storage applications. C60 {center_dot} H18.7 was prepared at 100 bar H2 and 400 C, corresponding to hydrogen uptake of 2.6 wt%. Dehydrogenation of C60 {center_dot} H18.7 was studied using thermogravimetric and powder x-ray diffraction analysis. The C60 {center_dot} H18.7 molecule was found to be stable up to 430 C in Ar, at which point the release of hydrogen took place simultaneously with the collapse of the fullerene structure. X-ray diffraction analysis performed on C60 {center_dot} H18.7 samples dehydrogenated at 454 C, 475 C, and 600 C showed an increasing volume fraction of amorphous material due to randomly oriented, single-layer graphine sheets. Evolved gas analysis using gas chromatography and mass spectroscopy confirmed the presence of both H{sub 2} and methane upon dehydrogenation, indicating decomposition of the fullerene. The remaining carbon could not be re-hydrogenated. These results provide the first complete evidence for the irreversible nature of fullerene hydrogenation and for limitations imposed on the hydrogenation/dehydrogenation cycle by the limited thermal stability of the molecular crystal of fullerene.

  9. Solubility of fullerenes in n -alkanoic acids C 2 –C 9

    Microsoft Academic Search

    K. N. Semenov; N. A. Charykov; A. K. Pyartman; V. A. Keskinov; V. V. Lishchuk; O. V. Arapov; N. I. Alekseev

    2007-01-01

    The solubility of fullerene C60 and a fullerene mixture [C60 (75%), C70 (24%), C76–80 (1%)] in linear alkanoic acids (C2–C9) was determined at 20°C. The solubilities of C60 and a fullerene mixture in carboxylic acids were examined in relation to the number of carbon atoms in the carboxylic acid.

  10. Ni-Catalyzed direct 1,4-difunctionalization of [60]fullerene with benzyl bromides.

    PubMed

    Si, Weili; Zhang, Xuan; Asao, Naoki; Yamamoto, Yoshinori; Jin, Tienan

    2015-04-14

    A new Ni-catalyzed direct 1,4-difunctionalization of [60]fullerene with various benzyl bromides has been developed. The use of a DMSO additive combined with a nickel catalyst is indispensable for the formation of 1,4-dibenzyl fullerenes with a variety of functional groups. The reaction proceeds through the formation of a fullerene monoradical species. PMID:25765232

  11. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, February 1944 - March 1945

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents February 1944 ? March 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  12. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, December 1944 - January 1945

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents December 1944 ? January 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  13. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, April 1944 - November 1944

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories April 1944 ? November 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  14. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 18 July 1942- 7 February 1943

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Missions: 18 July 1942 ? 7 February 1943. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical... Association, IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the missions of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from...

  15. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 5 March 1944 - 18 August 1944

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Missions: 5 March 1944 ? 18 August 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force... Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical Association, Maxwell...

  16. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 1 May 1946 - 31 July 1946

    E-print Network

    United States Army Air Corps; United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents 1 May 1946 ? 31 July 1946. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  17. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, April 1945 - November 1945

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents April 1945 ? November 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  18. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, April 1945 - November 1945 

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents April 1945 ? November 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  19. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 1 May 1946 - 31 July 1946 

    E-print Network

    United States Army Air Corps; United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents 1 May 1946 ? 31 July 1946. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  20. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, December 1944 - January 1945 

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents December 1944 ? January 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  1. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, February 1944 - March 1945 

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents February 1944 ? March 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  2. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, April 1944 - November 1944 

    E-print Network

    United States Army Air Corps

    1946-01-01

    42nd Bombardment Squadron (H) Monthly Squadron Histories April 1944 ? November 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943... - ) Air Force Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical...

  3. JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

    SciTech Connect

    Turrini, D.; Coradini, A.; Magni, G., E-mail: diego.turrini@ifsi-roma.inaf.it [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, 00133, Rome (Italy)

    2012-05-01

    The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.

  4. Stability of carbonaceous dust analogues and glycine under UV irradiation and electron bombardment.

    PubMed

    Maté, Belén; Tanarro, Isabel; Moreno, Miguel A; Jiménez-Redondo, Miguel; Escribano, Rafael; Herrero, Víctor J

    2014-01-01

    The effect of UV photon (120-200 nm) and electron (2 keV) irradiation of analogues of interstellar carbonaceous dust and of glycine were investigated by means of IR spectroscopy. Films of hydrogenated amorphous carbon (HAC), taken as dust analogues, were found to be stable under UV photon and electron bombardment. High fluences of photons and electrons, of the order of 10(19) cm(-2), were needed for a film depletion of a few percent. UV photons were energetically more effective than electrons for depletion and led to a certain dehydrogenation of the HAC samples, whereas electrons led seemingly to a gradual erosion with no appreciable changes in the hydrocarbon structure. The rates of change observed may be relevant over the lifetime of a diffuse cloud, but cannot account for the rapid changes in hydrocarbon IR bands during the evolution of some proto-planetary nebulae. Glycine samples under the same photon and electron fluxes decay at a much faster rate, but tend usually to an equilibrium value different from zero, especially at low temperatures. Reversible reactions re-forming glycine, or the build-up of less transparent products, could explain this behavior. CO2 and methylamine were identified as UV photoproducts. Electron irradiation led to a gradual disappearance of the glycine layers, also with formation of CO2. No other reaction products were clearly identified. The thicker glycine layers (a few hundred nm) were not wholly depleted, but a film of the order of the electron penetration depth (80 nm), was totally destroyed with an electron fluence of -1 x 10(18) cm(-2). A 60 nm ice layer on top of glycine provided only partial shielding from the 2 keV electrons. From an energetic point of view, 2 keV electrons are less efficient than UV photons and, according to literature data, much less efficient than MeV protons for the destruction of glycine. The use of keV electrons to simulate effects of cosmic rays on analogues of interstellar grains should be taken with care, due to the low penetration depths of electrons in many samples of interest. PMID:25302385

  5. Structures and electronic properties of fullerene-related compounds

    SciTech Connect

    Hettich, R.L.; Ying, Z.C.; Compton, R.N. [Oak Ridge National Lab., TN (United States)

    1995-12-31

    The synthesis and characterization of fullerene-related compounds has been the subject of active research both experimentally and theoretically since the discovery of C{sub 60}. For example, endohedral fullerenes M@C{sub n} (carbon clusters containing a {open_quotes}trapped{close_quotes} atom M within their cage) can be generated for several different early transition metals and noble gases. The properties of these species have been modelled theoretically, and indicate that these species may have unusual applications. Likewise, the covalent attachment of hydrocarbon functional groups to a fullerene also alters its properties, opening up new applications as well. The focus of this presentation is to describe how Fourier transform ion cyclotron resonance (FTICR) can be used not only for the detection and identification of fullerene-related compounds, but also the detailed structural interrogation of their properties. In particular, laser desorption FTICR was used to examine endohedral La@C{sub n} species and {gamma}-radiolysis fullerene products. Collisional dissociation and charge transfer processes were used to probe the structures and electronic properties of these nanoclusters in detail.

  6. Energy and photoinduced electron transfer in porphyrin-fullerene dyads

    SciTech Connect

    Kuciauskas, D.; Lin, S.; Seely, G.R.; Moore, A.L.; Moore, T.A.; Gust, D. [Arizona State Univ., Tempe, AZ (United States)] [Arizona State Univ., Tempe, AZ (United States); Drovetskaya, T.; Reed, C.A. [Univ. of Southern California, Los Angeles, CA (United States)] [Univ. of Southern California, Los Angeles, CA (United States); Boyd, P.D.W. [Univ. of Auckland (New Zealand)] [Univ. of Auckland (New Zealand)

    1996-09-26

    Time-resolved fluorescence and absorption techniques have been used to investigate energy and photoinduced electron transfer in a covalently linked free-base porphyrin-fullerene dyad and its zinc analogue. In toluene, the porphyrin first excited singlet states decay in about 20 ps by singlet-singlet energy transfer to the fullerene. The fullerene first excited singlet state is not quenched and undergoes intersystem crossing to the triplet, which exists in equilibrium with the porphyrin triplet state. In benzonitrile, photoinduced electron transfer from the porphyrin first excited singlet state to the fullerene competes with energy transfer. The fullerene excited singlet state is also quenched by electron transfer from the porphyrin. Overall, the charge-separated state is produced with a quantum yield approaching unity. This state lives for 290 ps in the free-base dyad and 50 ps in the zinc analog. These long lifetimes suggest that such dyads may be useful as components of more complex light-harvesting systems. 32 refs., 12 figs., 1 tab.

  7. The mechanism of oxidation of fullerenes with molecular oxygen

    SciTech Connect

    Wohlers, M.; Bauer, A.; Belz, Th [Fritz Haber Institute der Max Planck Gesellschaft, Berlin (Germany)] [and others

    1996-12-31

    The novel allotrope of carbon, fullerene is a molecular analogue to the other form of sp hybridised carbon, graphite. In our general attempt to understand the carbon-oxygen reaction at an atomic level we use fullerenes as reference compounds in oxidation studies as they will not exhibit influences of electronic defects on the reactivity. The van der Waals crystals of C{sub 60} and of C{sub 70} can be prepared by slow sublimation with single crystalline quality and in absence of any detectable phase impurity due to the molecular separation procedures for the sublimation precursors. It is equally convenient to work on thin films of fullerenes on e.g. silicon (100) surfaces, on large single crystals and on sublimed powder. Solid fullerenes are air-sensitive materials. They degrade quickly within minutes into a stage of reduced solubility and become eventually fully polymerized upon air/sunlight exposure at 300 K. This property is reminiscent on coal degradation, a process in which a variety of gases are released at low rates. We first investigate this initial step of reactivity of fullerenes with air using temperature-programmed methods.

  8. Fullerene oxidation and clustering in solution induced by light.

    PubMed

    Dattani, Rajeev; Gibson, Kirsty F; Few, Sheridan; Borg, Aaron J; DiMaggio, Peter A; Nelson, Jenny; Kazarian, Sergei G; Cabral, João T

    2015-05-15

    We investigate the environmental stability of fullerene solutions by static and dynamic light scattering, FTIR, NMR and mass spectroscopies, and quantum chemical calculations. We find that visible light exposure of fullerene solutions in toluene, a good solvent, under ambient laboratory conditions results in C60 oxidation to form fullerene epoxides, and subsequently causes fullerene clustering in solution. The clusters grow with time, even in absence of further illumination, and can reach dimensions from ?100 nm to the ?m scale over ?1 day. Static light scattering suggests that resulting aggregates are fractal, with a characteristic power law (d(f)) that increases from approximately 1.3 to 2.0 during light exposure. The clusters are bound by weak Coulombic interactions and are found to be reversible, disintegrating by mechanical agitation and thermal stress, and reforming over time. Our findings are relevant to the solution processing of composites and organic photovoltaics, whose reproducibility and performance requires control of fullerene solution stability under storage conditions. PMID:25646787

  9. Fullerene data mining using bibliometrics and database tomography

    PubMed

    Kostoff; Braun; Schubert; Toothman; Humenik

    2000-01-01

    Database tomography (DT) is a textual database analysis system consisting of two major components: (1) algorithms for extracting multiword phrase frequencies and phrase proximities (physical closeness of the multiword technical phrases) from any type of large textual database, to augment (2) interpretative capabilities of the expert human analyst. DT was used to derive technical intelligence from a fullerenes database derived from the Science Citation Index and the Engineering Compendex. Phrase frequency analysis by the technical domain experts provided the pervasive technical themes of the fullerenes database, and phrase proximity analysis provided the relationships among the pervasive technical themes. Bibliometric analysis of the fullerenes literature supplemented the DT results with author/journal/institution publication and citation data. Comparisons of fullerenes results with past analyses of similarly structured near-earth space, chemistry, hypersonic/supersonic flow, aircraft, and ship hydrodynamics databases are made. One important finding is that many of the normalized bibliometric distribution functions are extremely consistent across these diverse technical domains and could reasonably be expected to apply to broader chemical topics than fullerenes that span multiple structural classes. Finally, lessons learned about integrating the technical domain experts with the data mining tools are presented. PMID:10661546

  10. ON THE EXCITATION AND FORMATION OF CIRCUMSTELLAR FULLERENES

    SciTech Connect

    Bernard-Salas, J.; Jones, A. P. [Institut d'Astrophysique Spatiale, CNRS/Universite Paris-Sud 11, F-91405 Orsay (France); Cami, J.; Peeters, E.; Micelotta, E. R. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada); Groenewegen, M. A. T., E-mail: jbernard@ias.u-psud.fr [Royal Observatory of Belgium, Ringlaan 3, B-1180 Brussels (Belgium)

    2012-09-20

    We compare and analyze the Spitzer mid-infrared spectrum of three fullerene-rich planetary nebulae in the Milky Way and the Magellanic Clouds: Tc1, SMP SMC 16, and SMP LMC 56. The three planetary nebulae share many spectroscopic similarities. The strongest circumstellar emission bands correspond to the infrared active vibrational modes of the fullerene species C{sub 60} and little or no emission is present from polycyclic aromatic hydrocarbons. The strengths of the fullerene bands in the three planetary nebulae are very similar, while the ratios of the [Ne III]15.5 {mu}m/[Ne II]12.8 {mu}m fine structure lines, an indicator of the strength of the radiation field, are markedly different. This raises questions about their excitation mechanism and we compare the fullerene emission to fluorescent and thermal models. In addition, the spectra show other interesting and common features, most notably in the 6-9 {mu}m region, where a broad plateau with substructure dominates the emission. These features have previously been associated with mixtures of aromatic/aliphatic hydrocarbon solids. We hypothesize on the origin of this band, which is likely related to the fullerene formation mechanism, and compare it with modeled hydrogenated amorphous carbon that present emission in this region.

  11. The first stable lower fullerene: C{sub 36}

    SciTech Connect

    Piskoti, C.; Zettl, A. [Department of Physics, University of California, Berkeley, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    1998-08-01

    A new pure carbon material, presumably composed of thirty six carbon atom molecules, has been synthesized and isolated in milligram quantities. It appears as though these molecules have a closed cage structure making them the smallest member of a new class of molecules known as fullerenes, most notably of which is the soccer ball shaped C{sub 60}. However, unlike other known fullerenes, any closed, fullerene-like C{sub 36} cage will necessarily contain fused pentagon rings. Therefore, this molecule apparently violates the isolated pentagon rule, a criterion which requires isolated pentagons for stability in fullerene molecules. Striking parallels between this problem and the synthesis of other fused five member fused ring systems will be discussed. Also, it will be shown that certain biological structures known as clathrin behave in a manner which gives excellent predictions about fullerenes and nanotubes. These predictions help to explain the presence of abundant quantities of C{sub 36} in arced graphite soot. {copyright} {ital 1998 American Institute of Physics.}

  12. Enhancement of the 6.4 keV Line in the Inner Galactic Ridge: Proton-induced Fluorescence?

    NASA Astrophysics Data System (ADS)

    Nobukawa, K. K.; Nobukawa, M.; Uchiyama, H.; Tsuru, T. G.; Torii, K.; Tanaka, T.; Chernyshov, D. O.; Fukui, Y.; Dogiel, V. A.; Koyama, K.

    2015-07-01

    A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this scenario, the flux should symmetrically distribute between the east and west on the plane with respect to Sagittarius A* because the stellar mass distribution determined by infrared observations is nearly symmetric. This symmetry is confirmed for the highly ionized iron line as well as the continuum emission. However, a clear excess of the neutral iron line in the near east of the Galactic center compared to the near-west side is found. The flux distribution of the excess emission well correlates with the molecular column density. The X-ray spectrum of the excess emission is described by a power-law continuum plus a 6.4 keV line with a large equivalent width of ?1.3 keV, which is hardly explained by the low-energy electron bombardment scenario. The longitudinal and latitudinal distribution of the excess emission disfavors the X-ray irradiation, either by Sagittarius A* or by nearby X-ray binaries. Then, the low-energy proton bombardment is the most probable origin, although the high-energy density ?80 eV cm?3 in 0.1–1000 MeV is required and there is no conventional proton source in the vicinity.

  13. New weight-loss measurements of the chemical erosion yields of carbon materials under hydrogen ion bombardment

    NASA Astrophysics Data System (ADS)

    Balden, M.; Roth, J.

    2000-06-01

    Total erosion yields of graphite and carbon materials under hydrogen and deuterium bombardment measured with the weight-loss method are presented for ion energies between 15 eV and 8 keV in the temperature range 300 to above 1000 K. The temperature of the maximum of the chemical erosion increases from below 600 to above 850 K with ion energies from 15 to 300 eV. Chemical erosion yields obtained by weight-loss measurements exceed yields measured mass-spectrometrically always by a factor of about two. Collector experiments show that a fraction of the eroded particle sticks to walls and, therefore, reduces the yield measured by mass spectrometry. A synergistic effect of neutrals in the ion beam on the chemical erosion yield can be excluded.

  14. Thermally induced amorphous to crystalline transformation of argon ion bombarded GaAs studied with surface Brillouin and Raman scattering

    NASA Astrophysics Data System (ADS)

    Jakata, K.; Wamwangi, D. M.; Sumanya, C.; Mathe, B. A.; Erasmus, R. M.; Naidoo, S. R.; Comins, J. D.

    2012-09-01

    Surface Brillouin scattering (SBS) and Raman spectroscopy have been used to investigate the recrystallisation of an amorphous layer of GaAs created on single crystal (0 0 1) GaAs by ion bombardment with 100 keV argon ions with a fluence of 5 × 1016 ions/cm2 at a temperature of ˜65 °C. Samples were isochronally annealed and the light scattering measurements were performed after each annealing step. The SBS studies confirm structural changes resulting in continuous stiffening of the layer beginning above 200 °C and finally attaining a maximum value above 500 °C. The Raman studies show evidence of full recrystallisation above 500 °C, with the appearance of both LO and TO peaks indicating that the reformed layer is polycrystalline.

  15. A study of fullerene-quantum dot composite structure on substrates with a transparent electrode layer

    NASA Astrophysics Data System (ADS)

    Pavlov, S. I.; Kirilenko, D. A.; Nashchekin, A. V.; Sokolov, R. V.; Konnikov, S. G.

    2015-02-01

    We have studied the structure of films consisting of fullerene clusters and a related fullerene-based composite with incorporated quantum dots. The films were obtained by electrophoretic deposition from solution onto glass substrates with a transparent indium-doped tin oxide (ITO) electrode layer. The average cluster size, as measured by electron microscopy, amounts to 300 nm in pure fullerene films and 800 nm in the composite material. Electron diffraction measurements showed that pure fullerene clusters had an fcc lattice, while the introduction of quantum dots rendered the fullerene matrix predominantly amorphous.

  16. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source.

    PubMed

    Asaji, T; Ohba, T; Uchida, T; Minezaki, H; Ishihara, S; Racz, R; Muramatsu, M; Biri, S; Kitagawa, A; Kato, Y; Yoshida, Y

    2014-02-01

    A synthesis technology of endohedral fullerenes such as Fe@C60 has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C60 was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction. PMID:24593515

  17. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Asaji, T.; Ohba, T.; Uchida, T.; Minezaki, H.; Ishihara, S.; Racz, R.; Muramatsu, M.; Biri, S.; Kitagawa, A.; Kato, Y.; Yoshida, Y.

    2014-02-01

    A synthesis technology of endohedral fullerenes such as Fe@C60 has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C60 was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

  18. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

    SciTech Connect

    Asaji, T., E-mail: asaji@oshima-k.ac.jp; Ohba, T. [Oshima National College of Maritime Technology, 1091-1 Komatsu, Suo-oshima, Oshima, Yamaguchi 742-2193 (Japan)] [Oshima National College of Maritime Technology, 1091-1 Komatsu, Suo-oshima, Oshima, Yamaguchi 742-2193 (Japan); Uchida, T.; Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)] [Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Minezaki, H.; Ishihara, S. [Graduate School of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan)] [Graduate School of Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585 (Japan); Racz, R.; Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem Tér 18/c (Hungary)] [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem Tér 18/c (Hungary); Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)] [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    A synthesis technology of endohedral fullerenes such as Fe@C{sub 60} has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C{sub 60} was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

  19. Liposome Formulation of Fullerene-Based Molecular Diagnostic and Therapeutic Agents

    PubMed Central

    Zhou, Zhiguo

    2013-01-01

    Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compounds with very promising preclinical efficacy, pharmacokinetic and safety data. However, there is no clinical evaluation or human use except in fullerene-based cosmetic products for human skincare. This article summarizes recent advances in liposome formulation of fullerenes for the use in therapeutics and molecular imaging. PMID:24300561

  20. NEUTRON ACTIVATION CROSS SECTIONS AT 25 Kev

    Microsoft Academic Search

    Rex Booth; William Ball; Malcolm MacGregor

    1958-01-01

    Neutron activation cross sections have been measured at 25 kev for 31 ; isotopes. An Sb-Be photoneutron source was used, and thermal activations served ; to calibrate the beta- and gamma-detector efficiencies. The cross sections were ; measnred relative to iodine. A comparison was made between measured cross ; sections and predictions based on known low-energy resonance parameters. (auth);

  1. Neutron Activation Cross Sections at 25 kev

    Microsoft Academic Search

    Rex Booth; William P. Ball; Malcolm H. MacGregor

    1958-01-01

    Neutron activation cross sections have been measured at 25 kev for 31 isotopes. An Sb-Be photoneutron source was used, and thermal activations served to calibrate the beta- and gamma-detector efficiencies. The cross sections were measured relative to iodine. A comparison was made between measured cross sections and predictions based on known low-energy resonance parameters.

  2. Multilayer diffraction at 104 keV

    NASA Technical Reports Server (NTRS)

    Krieger, Allen S.; Blake, Richard L.; Siddons, D. P.

    1993-01-01

    We have measured the diffraction peak of a W:Si synthetic multilayer reflector at 104 keV using the High Energy Bonse-Hart Camera at the X-17B hard X-ray wiggler beam line of the National Synchrotron Light Source at Brookhaven National Laboratory. The characteristics of the diffraction peak are described and compared to theory.

  3. Exploration in metallic nitride fullerenes and oxometallic fullerenes: A new class of metallofullerenes

    NASA Astrophysics Data System (ADS)

    Mackey, Mary Alice

    2011-07-01

    Research groups around the world have taken an interest in the synthesis, purification, characterization, and functionalization of Metallic Nitride Fullerenes (MNFs) since their discovery in 1999. This dissertation details the discovery of another new class of molecules---Oxometallic Fullerenes (OMFs). There are many groups worldwide doing research on MNFs, and there is a large database of published MNF research, but we have had a unique opportunity to fill a research void on OMFs as at present no one else is doing research on these molecules; herein we take molecules that we discover and perform seminal research relating to them. MNF research is closely tied to this project; MNFs are a stepping stone because of their greater abundance and similar reactivity. Building off of previously developed techniques, we are able to create new methods for the separation and isolation of MNFs and OMFs. We studied the reactivity differences of various MNFs and OMFs in order to utilize Lewis acid chemistry as a tool for the enrichment and purification of both MNFs and OMFs, eventually resulting in a detailed separations technique. We have also begun studies to functionalize the carbon cage of endohedral metallofullerenes---this research includes using Lewis acids and various aromatic solvents via Friedel-Crafts reactions.

  4. TEM study of diamond films grown from fullerene precursors

    SciTech Connect

    Csencsits, R.; Gruen, D.M.; Krauss, A.R.; Zuiker, C.

    1995-11-01

    Transmission Electron Microscope (TEM) techniques are applied to study the microstructure of diamond films grown from fullerene precursors. Electron diffraction and electron energy loss spectra (EELS) collected from the diamond films correspond to that of bulk diamond. Microdiffraction, high resolution images and EELS help determine that the first diamond grains that nucleate from fullerene precursors generally form on a thin amorphous carbon interlayer and seldom directly on the silicon substrate. Grain size measurements reveal nanocrystalline diamond grains. Cross section TEM images show that the nanocrystalline diamond grains are equiaxed and not columnar nor dendritic. The microstructure of small equiaxed grains throughout the film thickness is believed responsible for the very smooth surfaces of diamond films grown from fullerene precursors.

  5. THE FORMATION OF COSMIC FULLERENES FROM AROPHATIC CLUSTERS

    SciTech Connect

    Micelotta, Elisabetta R.; Cami, Jan; Peeters, Els; Fanchini, Giovanni [Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7 (Canada)] [Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 3K7 (Canada); Jones, Anthony P.; Bernard-Salas, Jeronimo, E-mail: emicelot@uwo.ca [Institut d'Astrophysique Spatiale, CNRS/Universite Paris Sud, F-91405 Orsay (France)] [Institut d'Astrophysique Spatiale, CNRS/Universite Paris Sud, F-91405 Orsay (France)

    2012-12-10

    Fullerenes have recently been identified in space and they may play a significant role in the gas and dust budget of various astrophysical objects including planetary nebulae (PNe), reflection nebulae, and H II regions. The tenuous nature of the gas in these environments precludes the formation of fullerene materials following known vaporization or combustion synthesis routes even on astronomical timescales. We have studied the processing of hydrogenated amorphous carbon (a-C:H or HAC) nanoparticles and their specific derivative structures, which we name ''arophatics'', in the circumstellar environments of young, carbon-rich PNe. We find that UV-irradiation of such particles can result in the formation of fullerenes, consistent with the known physical conditions in PNe and with available timescales.

  6. Superextended Tetrathiafulvalene: Synthesis, Optoelectronic Properties, Fullerenes Complexation, and Photooxidation Study.

    PubMed

    Giguère, Jean-Benoît; Morin, Jean-François

    2015-07-01

    Superextended tetrathiafulvalene compounds were prepared by the substitution of gem-dichlorovinylene with 1,2-benzenedithiol. This strategy allowed for the efficient synthesis of a highly ?-extended 9,10-bis(benzo-1,3-dithiol-2-ylidene)-9,10-dihydroanthracene (sExTTF) moiety, which exhibits an intense light absorption in the visible spectrum and a reversible oxidation process. A macrocyclic host for fullerenes containing two sExTTF units was synthesized. Complexation studies revealed that fullerenes promote the photooxidation of the 1,3-dithiolylidene bond. This grants new insights into the nature of the low-energy band that appeared in several reports on fullerene complexation with hosts containing the 1,3-dithiolylidene moiety. PMID:26069942

  7. Ultralow thermal conductivity of fullerene derivatives

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojia; Liman, Christopher D.; Treat, Neil D.; Chabinyc, Michael L.; Cahill, David G.

    2013-08-01

    Recently, Duda [J. C. Duda, P. E. Hopkins, Y. Shen, and M. C. Gupta, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.110.015902 110, 015902 (2013)] reported that the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) has the lowest thermal conductivity ? ever observed in a fully dense solid, ? ? 0.03 W m-1 K-1. We have investigated a variety of phases and microstructures of PCBM and the closely related compound [6,6]-phenyl-C61-butyric acid n-butyl ester (PCBNB) and find that the thermal conductivities of PCBM and PCBNB films are mostly limited to the range 0.05 < ? < 0.06 W m-1 K-1 with a few samples having slightly higher ?. The conductivities we observe are ?70% larger than reported by Duda but are still “ultralow” in the sense that the thermal conductivity is a factor of ?3 below the conductivity predicted by the minimum thermal conductivity model using an estimate of the thermally excited modes per molecule.

  8. Endohedral fullerenes for organic photovoltaic devices.

    PubMed

    Ross, Russel B; Cardona, Claudia M; Guldi, Dirk M; Sankaranarayanan, Shankara Gayathri; Reese, Matthew O; Kopidakis, Nikos; Peet, Jeff; Walker, Bright; Bazan, Guillermo C; Van Keuren, Edward; Holloway, Brian C; Drees, Martin

    2009-03-01

    So far, one of the fundamental limitations of organic photovoltaic (OPV) device power conversion efficiencies (PCEs) has been the low voltage output caused by a molecular orbital mismatch between the donor polymer and acceptor molecules. Here, we present a means of addressing the low voltage output by introducing novel trimetallic nitride endohedral fullerenes (TNEFs) as acceptor materials for use in photovoltaic devices. TNEFs were discovered in 1999 by Stevenson et al. ; for the first time derivatives of the TNEF acceptor, Lu(3)N@C(80), are synthesized and integrated into OPV devices. The reduced energy offset of the molecular orbitals of Lu(3)N@C(80) to the donor, poly(3-hexyl)thiophene (P3HT), reduces energy losses in the charge transfer process and increases the open circuit voltage (Voc) to 260 mV above reference devices made with [6,6]-phenyl-C(61)-butyric methyl ester (C(60)-PCBM) acceptor. PCEs >4% have been observed using P3HT as the donor material. This work clears a path towards higher PCEs in OPV devices by demonstrating that high-yield charge separation can occur with OPV systems that have a reduced donor/acceptor lowest unoccupied molecular orbital energy offset. PMID:19202546

  9. Endohedral Fullerenes for Organic Photovoltaic Devices

    SciTech Connect

    Ross, R. B.; Cardona, C. M.; Guldi, D. M.; Sankaranarayanan, S. G.; Reese, M. O.; Kopidakis, N.; Peete, J.; Walker, B.; ZBazan, G. C.; Van Keuren, E.; Holloway,; B. C.; Drees, M.

    2009-03-01

    So far, one of the fundamental limitations of organic photovoltaic (OPV) device power conversion efficiencies (PCEs) has been the low voltage output caused by a molecular orbital mismatch between the donor polymer and acceptor molecules. Here, we present a means of addressing the low voltage output by introducing novel trimetallic nitride endohedral fullerenes (TNEFs) as acceptor materials for use in photovoltaic devices. TNEFs were discovered in 1999 by Stevenson et al.; for the first time derivatives of the TNEF acceptor, Lu{sub 3}N{at}C{sub 80}, are synthesized and integrated into OPV devices. The reduced energy offset of the molecular orbitals of Lu{sub 3}N{at}C{sub 80} to the donor, poly(3-hexyl)thiophene (P3HT), reduces energy losses in the charge transfer process and increases the open circuit voltage (V{sub oc}) to 260 mV above reference devices made with [6,6]-phenyl-C{sub 61}-butyric methyl ester (C{sub 60}-PCBM) acceptor. PCEs >4% have been observed using P3HT as the donor material. This work clears a path towards higher PCEs in OPV devices by demonstrating that high-yield charge separation can occur with OPV systems that have a reduced donor/acceptor lowest unoccupied molecular orbital energy offset.

  10. Unconventional Superconductivity of Alkali-doped Fullerenes

    NASA Astrophysics Data System (ADS)

    Potocnik, Anton; Krajnc, Andraz; Jeglic, Peter; Prassides, Kosmas; Rosseinsky, Matthew J.; Arcon, Denis

    2014-03-01

    The superconductivity of the alkali-doped fullerenes (A3C60, A = alkali metal) has been so far discussed within the standard theory of superconductivity developed by Bardeen, Cooper and Shrieffer (BCS), even thought, they exhibit relatively high critical temperatures (up to Tc = 32 K). However, after our recent high-pressure measurements on Cs3C60 such description became questionable. We have shown that the superconducting phase of A3C60, in fact, borders the antiferromagnetic insulating phase (AFI), commonly observed for high-temperature superconductors like cuprates or pnictides. In addition, we also increased the maximal Tc to 38 K. To investigate this peculiar superconductivity close to the border with AFI state we employed nuclear magnetic resonance technique on Cs3-xRbxC60 and on Cs3C60 at various high pressures. Our results could not be correctly explained either by the standard BCS or the extended BCS that includes electron-electron repulsion interaction - the Migdal-Eliashberg theory. Far better agreement is obtained by the Dynamical Mean Field Theory. Due to similarity with other unconventional superconductors these results could also be relevant to other unconventional high-temperature superconductors.

  11. Photodynamic therapy using glycol chitosan grafted fullerenes.

    PubMed

    Kwag, Dong Sup; Oh, Nam Muk; Oh, Young Taik; Oh, Kyung Taek; Youn, Yu Seok; Lee, Eun Seong

    2012-07-15

    Glycol chitosan (GC)-grafted fullerene (GC-g-C(60)) conjugates were developed for use in photodynamic therapy of tumor cells. GC-g-C(60) was synthesized in anhydrous benzene/dimethylsulfoxide (DMSO) co-solvent via the chemical conjugation of free amine groups of GC to CC double bonds of C(60). The GC-g-C(60) with 5×10(-4) C(60) molecules per one repeating unit of GC was soluble in water. As C(60) molecules conjugated to GC increased to 0.16 molecules per one repeating unit of GC, GC-g-C(60) started to form supramolecular assemblies (?30 nm) stabilized in phosphate buffer saline (PBS, 150 mM, pH 7.4). Upon 670 nm light illumination, photo-responsive properties of GC-g-C(60) allowed tremendous singlet oxygen generation in tumor cells for super phototoxicity. GC-g-C(60) also showed highly increased tumor accumulation ability for in vivo tumor of KB tumor-bearing nude mice. It is expected that our GC-g-C(60) conjugate may be a good candidate for in vivo photodynamic therapy in various malignant tumor cells. PMID:22537808

  12. plutonium isotopic analysis in the 30 KeV to 210 KeV range

    SciTech Connect

    Vo, Duc T.; Li, T. K. (Tien K.)

    2001-01-01

    Low-Energy Gamma-ray Spectroscopy (LEGS) is a nondestructive assay (NDA) technique developed in the 1980s. In 1999, it was modified to include a physical-based model for the energy dependent efficiency. It uses the gamma rays in the energy range from approximately 30 keV to 210 keV, except the 100-keV region. This energy region provides intense, well-separated gamma rays from the principal isotopes of plutonium. For applications involving small quantities (mg to g) of freshly separated plutonium in various chemical forms, it is ideally suited for accurate real-time or near real-time isotopic analysis. Since the last modification, LEGS has been incorporated into the FRAM code (Fixed-energy Response-function Analysis with Multiple efficiency), version 4. FRAM v4 is capable of analyzing the peaks in the whole energy range from 30 keV to 1 MeV, including the X-ray region. The new capability of analyzing the peaks in the 100-keV region greatly enhances the plutonium analysis in the 30 keV to 2 10 keV ranges of the traditional LEGS. We now can analyze both the freshly separated and aged plutonium with greater accuracy.

  13. Mapping fullerene crystallization in a photovoltaic blend: an electron tomography study

    NASA Astrophysics Data System (ADS)

    Bäcke, Olof; Lindqvist, Camilla; Diaz de Zerio Mendaza, Amaia; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R.; Müller, Christian; Olsson, Eva

    2015-04-01

    The formation of fullerene crystals represents a major degradation pathway of polymer/fullerene bulk-heterojunction thin films that inexorably deteriorates their photovoltaic performance. Currently no tools exist that reveal the origin of fullerene crystal formation vertically through the film. Here, we show that electron tomography can be used to study nucleation and growth of fullerene crystals. A model bulk-heterojunction blend based on a thiophene-quinoxaline copolymer and a fullerene derivative is examined after controlled annealing above the glass transition temperature. We image a number of fullerene nanocrystals, ranging in size from 70 to 400 nanometers, and observe that their center is located close to the free-surface of spin-coated films. The results show that the nucleation of fullerene crystals predominately occurs in the upper part of the films. Moreover, electron tomography reveals that the nucleation is preceded by more pronounced phase separation of the blend components.

  14. Theory of the Miscibility of Fullerenes in Random Copolymer Melts

    SciTech Connect

    Dadmun, Mark D [ORNL; Sumpter, Bobby G [ORNL; Schweizer, Kenneth [University of Illinois; Banerjee, Debapriya [University of Illinois, Urbana-Champaign

    2013-01-01

    We combine polymer integral equation theory and computational chemistry methods to study the interfacial structure, effective interactions, miscibility and spatial dispersion mechanism of fullerenes dissolved in specific random AB copolymer melts characterized by strong non-covalent electron donor-acceptor interactions with the nanofiller. A statistical mechanical basis is developed for designing random copolymers to optimize fullerene dispersion at intermediate copolymer compositions. Pair correlation calculations reveal a strong sensitivity of interfacial packing near the fullerene to copolymer composition and adsorption energy mismatch. The potential of mean force between fullerenes displays rich trends, often non-monotonic with copolymer composition, reflecting a non-additive competition between direct filler attractions and polymer-mediated bridging and steric stabilization. The spinodal phase diagrams are in qualitative agreement with recent solubility limit experimental observations on three systems, and testable predictions are made for other random copolymers. The distinctive non-monotonic variation of miscibility with copolymer composition is found to be primarily a consequence of composition-dependent, spatially short-range attractions between the A and B monomers with the fullerene. A remarkably rich, polymer-specific temperature dependence of the spinodal diagram is predicted which reflects the thermal sensitivity of spatial correlations which can result in fullerene miscibility either increasing or decreasing with cooling. The calculations are contrasted with a simpler effective homopolymer model and the random structure Flory-Huggins model. The former appears to be qualitatively reasonable but can incur large quantitative errors since it misses preferential packing of monomers near nanoparticles, while the latter appears to fail qualitatively due to its neglect of all spatial correlations.

  15. Single-fullerene manipulation inside a carbon nanotube

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Kirillova, I. V.; Saliy, I. N.; Slepchenkov, M. M.

    2011-03-01

    Here we are representing the results of the tight-binding molecular modeling of the process of the synthesis of the dimer (C28)2 and the retinoid-C60 linked molecules inside a carbon nanotube. The nanotube is located between two electrodes connected with a power source. The positively charged fullerene C60 moves from one end of the tube to the other. The motion of C60 is controlled by an external electric field. Moving fullerene C60 compresses the molecules located in one of the nanotube ends. The located molecules undergone axial compression moves toward each other. When the pressure created in the tube provides both the overlap of ?-electrons of the C28 fullerenes and the covalent bonds formation, the intermediate phase of the (C28)2 dimer is synthesized: (C28)2 [6 + 6]. The pressure becomes equal to ~35 TPa. After returning the fullerene C60 to the initial state, the (C28)2 dimer is izomerized with the reorientation in the tube field. So, (C28)2 transfers to the stable phase (C28)2 [1+1]. If the moving fullerene C60 compresses the retinol-molecule then synthesis of retinoid-C60 linked molecules takes place. In conclusion, the dimer/polymer synthesis inside the carbon nanotube is real, the dimers and polymers are stable and may be synthesized in the field of the holding potential nanotube, and the fullerene polymerization in the nanotube guarantees the absence of any additives in the final product. The motion of the atoms is determined by the classical molecular modeling method where Newton's equations of motion are integrated with a third-order Nordsieck predictor corrector. Time steps of 0.15-0.25 fs were used in the simulations.

  16. Protein interaction with hydrated C60 fullerene in aqueous solutions.

    PubMed

    Rozhkov, S P; Goryunov, A S; Sukhanova, G A; Borisova, A G; Rozhkova, N N; Andrievsky, G V

    2003-04-01

    Physicochemical effects of hydrated C(60) fullerenes (HyFn) on serum albumin molecules were studied using ESR spin labeling and differential scanning microcalorimetry. Molecular-colloidal solution of hydrated C(60) fullerenes and their small spherical fractal clusters in water (C(60)FWS), was shown to stabilize protein hydration, and decrease specific surface energy in water-protein matrix in salt solutions. The mechanism of HyFn interaction with protein is discussed in terms of HyFn induced formation of protein clusters and phase transition of hydration water. PMID:12659855

  17. Synthesis and characterizations of silver-fullerene C70 nanocomposite

    NASA Astrophysics Data System (ADS)

    Singhal, R.; Agarwal, D. C.; Mohapatra, S.; Mishra, Y. K.; Kabiraj, D.; Singh, F.; Avasthi, D. K.; Chawla, A. K.; Chandra, R.; Mattei, G.; Pivin, J. C.

    2008-09-01

    Films of C70 fullerene containing silver nanoparticles were synthesized by thermal codeposition. Optical absorption studies revealed that surface plasmon resonance of Ag nanoparticles occurs at unusually large wavelength, which showed a regular redshift from 521 to 581 nm with increase in metal content from 4.5% to 28%. It is explained by the Maxwell-Garnett theory considering the absorbing nature of fullerene matrix. Rutherford backscattering and transmission electron microscopy were performed to quantify metal content and the particle size, respectively. A better detection of low intensity vibrational modes of C70 in Raman scattering is observed due to surface enhanced Raman scattering.

  18. High-temperature phase diagram of the fullerene C60

    NASA Astrophysics Data System (ADS)

    Mederos, L.; Navascués, G.

    1994-07-01

    A density-functional approximation is used to study the high-temperature phase diagram of a system of fullerene C60 molecules which are considered as rigid spheres interacting via the Girifalco [J. Phys. Chem. 96, 858 (1992)] potential. We discuss the theoretical predictions together with the contradictory results given by computer simulations on the existence of a conventional liquid phase for the fullerene C60. Theory cannot definitively settle this point but the predictions for the melting and freezing lines are in quite good quantitative agreement with simulations results.

  19. Fullerenes: A New Carrier Phase for Noble Gases in Meteorites

    NASA Technical Reports Server (NTRS)

    Becker, Luann

    2004-01-01

    The major focus of our research effort has been to measure the noble gases encapsulated within fullerenes, a new carbon carrier phase and compare it to the myriad of components found in the bulk meteorite acid residues. We have concentrated on the carbonaceous chondrites (Allende, Murchison and Tagish Lake) since they have abundant noble gases, typically with a planetary signature that dominates the stepped-release of the meteorite bulk acid residue. They also contain an extractable fullerene component that can be isolated and purified from the same bulk material.

  20. Molecular dynamics simulations of hydrogen bombardment of tungsten carbide surfaces

    SciTech Connect

    Traeskelin, P.; Juslin, N.; Nordlund, K. [Association EURATOM-Tekes, Accelerator Laboratory, University of Helsinki, P.O. Box 43, FIN-00014 (Finland); Erhart, P. [Institut fuer Materialwissenschaft, Technische Universitaet Darmstadt, Petersenstrasse 23, D-64287 Darmstadt (Germany)

    2007-05-01

    The interaction between energetic hydrogen and tungsten carbide (WC) is of interest both due to the use of hydrogen-containing plasmas in thin-film manufacturing and due to the presence of WC in the divertor of fusion reactors. In order to study this interaction, we have carried out molecular dynamics simulations of the low-energy bombardment of deuterium impinging onto crystalline as well as amorphous WC surfaces. We find that prolonged bombardment leads to the formation of an amorphous WC surface layer, regardless of the initial structure of the WC sample. Loosely bound hydrocarbons, which can erode by swift chemical sputtering, are formed at the surface. Carbon-terminated surfaces show larger sputtering yields than tungsten-terminated surfaces. In both cumulative and noncumulative simulations, C is seen to sputter preferentially. Implications for mixed material erosion in ITER are discussed.

  1. Covalent dyads of porphyrin-fullerene and perylene-fullerene for organic photovoltaics: Spectroscopic and photocurrent studies

    NASA Astrophysics Data System (ADS)

    Wróbel, Danuta; Lewandowska, Kornelia

    2011-07-01

    Supermolecular complexes of zinc porphyrin or perylenediimide as covalent dyads with fullerene (C 60) in chloroform and as Langmuir-Blodgett layers on an Au substrate were studied. In our studies we have used following spectroscopic methods: electronic absorption, fluorescence and electron spin resonance in solution. Also infrared absorption spectra in a KBr pellet and reflectance-absorption in Langmuir-Blodgett layers were monitored. Photocurrent generation in a photoelectrochemical cell was also studied. The redistribution of charge both upon porphyrin linkage to C 60 and when the systems are deposited on the Au substrate was shown. Photocurrent examinations show a great influence of the fullerene presence on photoresponse of the systems.

  2. Storage of keV ion beams

    SciTech Connect

    Zajfman, Daniel; Bhushan, Kris G. [Department of Particle Physics, Weizmann Institute of Science, Rehovot, 76100 (Israel); Heber, Oded; Rappaport, Michael [Physics Services, Weizmann Institute of Science, Rehovot, 76100 (Israel)

    1999-01-15

    A new ion trap for storing fast (keV) ion beams is presented. The trap, which is electrostatic, stores the ions between two electrostatic mirrors. Two different examples of utilization of the trap are given. The first one required the extraction of the trapped particles after storage, in order to study their collision with an external target, while the second example measured the lifetime of the metastable He{sup -} levels. The advantage of storage using pure electrostatic fields is discussed.

  3. Multilayer, high resolution, ion-bombardment-tolerant electron resist system

    SciTech Connect

    Hunt, B.D.; Buhrman, R.A.

    1981-11-01

    A multilayer, high resolution electron resist system, which withstands ion bombardment, has been developed. This system consists of four layers which are, from top to bottom: AZ1350B, a thin metal interlayer, PMMA, and a copolymer of PMMA. The bottom two layers define the actual pattern dimensions. Two independent developers have been chosen for these two layers in order to obtain controllably undercut resist profiles ideal for liftoff applications, while maintaining high resolution in the upper PMMA layer. The top two layers of the four-level system serve to provide a protective metal coating which prevents crosslinking of the underlying polymer layer. This allows processing involving ion bombardment, such as ion milling or reactive ion etching. Without this protective metal layer, difficulty is often encountered in liftoff processing after ion bombardment, due to the presence of a thin crosslinked polymer layer which resists solvent penetration. This resist system has been used in conjunction with reactive ion beam oxidation to fabricate high quality, small area, niobium--lead alloy tunnel junctions in an edge geometry. Using a standard Cambridge EBMF-2 microfabricator, junctions with linewidths as small as 0.25 ..mu..m have been produced. With the edge geometry, this corresponds to junction areas smaller than 4 x 10/sup -10/ cm/sup 2/.

  4. Cobalt-catalyzed hydroalkylation of [60]fullerene with active alkyl bromides: selective synthesis of monoalkylated fullerenes.

    PubMed

    Lu, Shirong; Jin, Tienan; Bao, Ming; Yamamoto, Yoshinori

    2011-08-17

    The Co-catalyzed hydroalkylation of C(60) with reactive alkyl bromides 1 (RBr) in the presence of Mn reductant and H(2)O at ambient temperature gave the monoalkylated C(60) (2) in good to high yields. The use of CoLn/Mn/H(2)O under Ar atmosphere is crucial for the success of the present transformation. The reaction most probably proceeds through the Co(0 or I) complex-promoted generation of a radical (R(•)) followed by addition to C(60). This hydroalkylation method was applied to the synthesis of zinc porphyrin attached C(60) (2l), dendrimer attached C(60) (2m), and fullerene dimer (2n), which were not easily available through the previously known methods. PMID:21744823

  5. Sensitization of fullerenes by covalent attachment of a diketopyrrolopyrrole chromophore

    E-print Network

    Candea, George

    absorbs and then transfers the excitation energy to C60.10­13 Noteworthy are also conjugates for organic solar cell applications, we have synthesized triads of 3,6-dithien-2-yl-2,5-dialkylpyrrolo[3,4-c in photovoltaic devices containing fullerenes. Introduction In organic bulk heterojunction (BHJ) solar cells

  6. Fullerenes, fulleranes and polycyclic aromatic hydrocarbons in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bunch, T. E.

    1997-01-01

    In this paper, we confirm our earlier observations of fullerenes (C60 and C70) in the Allende meteorite (Becker et al., 1994a, 1995). Fullerene C60 was also detected in two separate C-rich (approximately 0.5-1.0%) dark inclusions (Heymann et al., 1987) that were hand picked from the Allende sample. The amounts of C60 detected were approximately 5 and approximately 10 ppb, respectively, which is considerably less than what was detected in the Allende 15/21 sample (approximately 100 ppb; Becker et al., 1994a, 1995). This suggests that fullerenes are heterogeneously distributed in the meteorite. In addition, we present evidence for fulleranes, (C60Hx), detected in separate samples by laser desorption (reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The LDMS spectra for the Allende extracts were remarkably similar to the spectra generated for the synthetic fullerane mixtures. Several fullerane products were synthesized using a Rh catalyst (Becker et al., 1993a) and separated using high-performance liquid chromatography (HPLC). Polycyclic aromatic hydrocarbons (PAHs) were also observed ppm levels) that included benzofluoranthene and corannulene, a cup-shaped molecule that has been proposed as a precursor molecule to the formation of fullerenes in the gas phase (Pope et al., 1993).

  7. Generating Fullerenes at Random Bor Plestenjak and Tomaz Pisanski

    E-print Network

    Plestenjak, Bor

    ;1. INTRODUCTION Fullerenes and other pure carbon cages remain a subject of active re- search. The mechanism that the presence of hydrogen and possibly carbon atoms lowers the activation energy and makes the SW to narrow the selection to a population of carbon cages with special properties. It is known that the SW

  8. Chromatographic fractionation of fullerenes containing noble gas atoms

    NASA Astrophysics Data System (ADS)

    Saunders, M.; Khong, A.; Shimshi, R.; Jiménez-Vázquez, H. A.; Cross, R. J.

    1996-01-01

    Buckminsterfullerence containing krypton atoms inside the cage was partially separated from empty fullerene via column chromatography. The krypton content of portions of the peak emerging from the column was determined by the pyrolytic release of the krypton followed by mass spectrometry. It was found that material emerging more slowly is about 30% enriched over a faster fraction.

  9. Radial distribution function of C60: Structure of fullerene

    Microsoft Academic Search

    Fang Li; D. Ramage; J. S. Lannin; J. Conceicao

    1991-01-01

    The structure of C60, fullerene clusters in the solid state has been obtained by a radial distribution function (rdf) determination. Neutron-diffraction measurements extending to Q values of 45 Å -1 yield rdf with thirteen distinct features at 300 K. This corresponds to the predicted number of groups of distances for the truncated icosohedral structure with thermal broadening. A comparison of

  10. Fullerene-based symmetry in Hibiscus rosa-sinensis pollen.

    PubMed

    Andrade, Kleber; Guerra, Sara; Debut, Alexis

    2014-01-01

    The fullerene molecule belongs to the so-called super materials. The compound is interesting due to its spherical configuration where atoms occupy positions forming a mechanically stable structure. We first demonstrate that pollen of Hibiscus rosa-sinensis has a strong symmetry regarding the distribution of its spines over the spherical grain. These spines form spherical hexagons and pentagons. The distance between atoms in fullerene is explained applying principles of flat, spherical, and spatial geometry, based on Euclid's "Elements" book, as well as logic algorithms. Measurements of the pollen grain take into account that the true spine lengths, and consequently the real distances between them, are measured to the periphery of each grain. Algorithms are developed to recover the spatial effects lost in 2D photos. There is a clear correspondence between the position of atoms in the fullerene molecule and the position of spines in the pollen grain. In the fullerene the separation gives the idea of equal length bonds which implies perfectly distributed electron clouds while in the pollen grain we suggest that the spines being equally spaced carry an electrical charge originating in forces involved in the pollination process. PMID:25003375

  11. Optical Spectroscopy of the Fullerenes C(60) and C(70)

    Microsoft Academic Search

    David J. Dick

    1996-01-01

    The fullerenes are a recently discovered third allotrope of carbon. The ability to produce these unusual molecules in gram quantities has led to intensive investigation of their properties. Optical spectroscopies provide powerful tools for investigating the electronic states of materials. We have used the techniques of resonant Raman scattering (RRS), electroabsorption (EA), cw and transient photomodulation (PM) and transient photoinduced

  12. Supersymmetry in spherical molecules and fullerenes under perpendicular magnetic fields.

    PubMed

    Jakubský, V; Kuru, S; Negro, J; Tristao, S

    2013-04-24

    Methods of supersymmetric quantum mechanics are used to obtain analytical solutions for massless Dirac electrons in spherical molecules, including fullerenes, in the presence of magnetic fields. The solutions for Dirac massive charges are also obtained via the solutions of the Dirac-Weyl equation. PMID:23553418

  13. Supersymmetry in spherical molecules and fullerenes under perpendicular magnetic fields

    NASA Astrophysics Data System (ADS)

    Jakubský, V.; Kuru, ?.; Negro, J.; Tristao, S.

    2013-04-01

    Methods of supersymmetric quantum mechanics are used to obtain analytical solutions for massless Dirac electrons in spherical molecules, including fullerenes, in the presence of magnetic fields. The solutions for Dirac massive charges are also obtained via the solutions of the Dirac-Weyl equation.

  14. Investigation of fullerenes for optoelectronic and photonic applications

    SciTech Connect

    Lee, H.W.H. [Lawrence Livermore National Lab., CA (United States)

    1995-12-31

    We present and discuss results outlining the use of fullerenes (mainly C{sub 60} and C{sub 70}) for optoelectronics and photonics. These applications are particularly compelling with the observation of such promising properties as photoluminescence, electroluminescence, large nonresonant optical nonlinearity, and superconductivity. We focus on nonlinear optical properties and their application to high-speed integrated all-optical switching. We present measurements on the dispersion and dynamics of the nonlinear optical coefficients in the near infrared and the figure-of-merit for photonic switching, indicating very favorable results. The first demonstration of photonic switching (all-optical logic gate, router, demultiplexor, etc.) using fullerene thin films as the nonlinear medium is presented. Our results show many advantages of fullerenes and fullerene devices, including the simplicity of processing into guided wave structures for nonlinear integrated optics, large nonlinear coefficients, effectively no latency, and potentially terabit/sec operation in the near infrared. Comparisons are made with the fiber optic switching approach.

  15. Hybrid uranium-oxalate fullerene topology cage clusters

    SciTech Connect

    Ling, Jie; Wallace, Christine M.; Szymanowski, Jennifer E.S.; Burns, Peter C

    2010-08-25

    Inorganic–organic hybrid cage clusters containing 36 and 60 uranyl peroxide polyhedra and 6 or 30 oxalate groups self-assemble in aqueous solution under ambient conditions. These clusters, which are derivatives of fullerene topologies, were crystallized for structure analysis, and are readily dissolved intact in water.

  16. Supramolecular gel-assisted formation of fullerene nanorods.

    PubMed

    Zhang, Chun; Wang, Jing; Wang, Jing-Jing; Li, Min; Yang, Xiang-Liang; Xu, Hui-Bi

    2012-11-19

    Gel it like it is: Fullerene nanorods (see figure) with a length of several micrometers, can be easily synthesized by a supramolecular gel-assisted self-assembly method (SGAS). The results presented here may be useful for the design and construction of new organic nanomaterials by SGAS. PMID:23112082

  17. Quenching and Sensitizing Fullerene Photoreactions by Natural Organic Matter

    EPA Science Inventory

    Effects of natural organic matter (NOM) on the photoreaction kinetics of fullerenes (i.e., C60 and fullerenol) were investigated using simulated sunlight and monochromatic radiation (365 nm). NOM from several sources quenched (slowed) the photoreaction of C60 aggregates in water ...

  18. Hydrogen peroxide production via electron bombardment on Europa: Laboratory studies

    Microsoft Academic Search

    K. P. Hand; R. W. Carlson

    2005-01-01

    Chemistry on the icy surface of Europa is heavily influenced by the 7.9e10 keV cm-2 s-1 incident particle flux resulting from the Jovian magnetic field. The majority (> 75%) of this energy is in the form of high energy (< 10 MeV) electrons. We have constructed a 1e-8 torr vacuum chamber equipped with a 100 keV electron gun and He-compressor

  19. Transformation of white spruce ( Picea glauca) somatic embryos by microprojectile bombardment

    Microsoft Academic Search

    V. R. Bommineni; R. N. Chibbar; R. S. S. Datla; E. W. T. Tsang

    1993-01-01

    Cotyledonary somatic embryos of white spruce [Picea glauca (Moench) Voss] were subjected to microprojectile bombardment with a gene construct containing a gus::nptll fusion gene. Somatic embryos were used to re-induce the embryogenic tissue after bombardments. Histochemical assay using X-gluc as a substrate showed that all the embryos (100%) were GUS positive 48 h after bombardment. However, only thirteen out of

  20. Electronic structure of the trimetal nitride fullerene Dy3 N@ C80

    Microsoft Academic Search

    H. Shiozawa; H. Rauf; T. Pichler; D. Grimm; X. Liu; M. Knupfer; M. Kalbac; S. Yang; L. Dunsch; B. Büchner; D. Batchelor

    2005-01-01

    We report on a detailed study of the electronic properties of the newly synthesized trimetal nitride fullerene Dy3N@C80 (isomer I) using high-energy spectroscopies as probes. From ultraviolet photoemission and C1s absorption spectroscopies we observe that the occupied and unoccupied electronic structures of the fullerene cage are very similar to those of other trimetal nitride fullerenes and hence both spectra exhibit

  1. Electrochemically formed two-component films comprised of fullerene and transition-metal components

    Microsoft Academic Search

    Krzysztof Winkler; Alan L. Balch

    2006-01-01

    This paper reviews the results of investigations into the electrochemical formation and properties of redox-active films formed from fullerenes and selected transition-metal complexes. These polymeric films are formed on the electrode surface during electroreduction of a solution containing a fullerene or a fullerene derivative and complexes of Pd(II), Pt(II), Rh(II) and Ir(I). The polymeric network is formed through covalent bonding

  2. One-pot selective synthesis of a fullerene bisadduct for organic solar cell applications.

    PubMed

    Zhang, Bolong; Subbiah, Jegadesan; Lai, Yu-Ying; White, Jonathan M; Jones, David J; Wong, Wallace W H

    2015-06-01

    A single isomer of fullerene bisadduct, PC61PF, was obtained from commercially available fullerene derivative, PC61BM, in one pot over two steps. The tether-directed remote functionalization approach provided a very simple and fast method to produce a single isomer of fullerene bisadduct with good yield and easy purification. Bulk heterojunction organic solar cells containing the bisadduct was fabricated and tested. PMID:25990490

  3. Modeling Charge Transfer in Fullerene Collisions via Real-Time Electron Dynamics

    SciTech Connect

    Jakowski, Jacek [ORNL; Irle, Stephan [ORNL; Morokuma, Keiji [ORNL; Sumpter, Bobby G [ORNL

    2012-01-01

    An approach for performing real-time dynamics of electron transfer in a prototype redox reaction that occurs in reactive collisions between neutral and ionic fullerenes is discussed. The quantum dynamical simulations show that the electron transfer occurs within 60 fs directly preceding the collision of the fullerenes, followed by structural changes and relaxation of electron charge. The consequences of real-time electron dynamics are fully elucidated for the far from equilibrium processes of collisions between neutral and multiply charged fullerenes.

  4. Pentacene:Fullerene Multilayer-Heterojunction Organic Photovoltaic Cells Fabricated by Alternating Evaporation Method

    Microsoft Academic Search

    Jun Sakai; Tetsuya Taima; Toshihiro Yamanari; Yuji Yoshida; Akihiko Fujii; Masanori Ozaki

    2010-01-01

    Novel small-molecule organic photovoltaic cell structures with pentacene and fullerene multilayers are reported. Pentacene is an attractive material for photovoltaic cells, but it tends to crystallize with molecular orientation during vacuum deposition. Therefore, thus far, it has been difficult to fabricate a bulk-heterojunction active layer with fullerenes by coevaporation, despite the demand for pentacene\\/fullerene bilayer heterojunction cells owing to their

  5. Synthesis and properties of novel water-soluble fullerene-glycine derivatives as new materials for cancer therapy.

    PubMed

    Jiang, Guichang; Yin, Fen; Duan, Jihua; Li, Guangtao

    2015-01-01

    Novel water-soluble fullerene-glycine derivatives were synthesized by means of simple organic chemistry. They are completely soluble in water, yielding a clear brown solution. The products were characterized by fourier transform infrared (FTIR), ultraviolet-visible spectroscopy (UV-Vis), (1)H NMR, (13)C NMR, thermogravimetric analyses (TGA), and scanning electron microscopy (SEM). The assembly behavior of water-soluble fullerene-glycine derivatives was investigated by SEM. The results show that the fullerene-glycine derivatives create morphology that is sphere-like. The cytotoxicity to cancer cell lines of the fullerene-glycine derivatives was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) and flow cytometry. The results show that fullerene-glycine derivatives exhibit mortality and apoptosis of the cells which increased with the increase of fullerene-glycine derivative concentration. The cytotoxicity mechanism of fullerene-glycine derivatives was investigated for the first time. Novel water-soluble fullerene-glycine derivatives were synthesized by means of simple organic chemistry. The products were characterized by FTIR, UV-Vis, (1)H NMR, (13)C NMR, TGA, and SEM. The bioactivities of fullerene-glycine derivative materials have been tested, and the results show that compared with the fullerene complex, the fullerene-glycine derivative materials exhibit mortality and apoptosis of the cells which increased with the increase of fullerene-glycine derivative concentration. SEM images showed the macrostructure of fullerene-glycine derivative materials was spheres. PMID:25578702

  6. Abstract Transgene loci in 16 transgenic oat (Avena sativa L.) lines produced by microprojectile bombard-

    E-print Network

    Pawlowski, Wojtek

    Abstract Transgene loci in 16 transgenic oat (Avena sativa L.) lines produced by microprojectile and rearrange- ments. Key words Genetic engineering · Oat (A. sativa L.) · Microprojectile bombardment · FISH

  7. Multisample probe for fast-atom bombardment / mass spectrometry.

    PubMed

    Siegel, M M; Tsao, R; Bouley, W; Kornas, T; Brubaker, G

    1993-06-01

    An inexpensive multisample fast-atom bombardment (FAB) probe assembly was designed for high-throughput analysis of samples on a VG ZAB-SE mass spectrometer. The system consists of a vacuum lock system and a FAB probe whose tip contains five or more sample wells. The probe enters the mass spectrometer source region perpendicular to the secondary ion beam axis, The probe is maintained at high voltage on contact with a spring clip attached to the screen plate of the source block. Sample throughput with the multisample probe is twice that of a coaxial probe, with about twice the sensitivity and no sample cross contamination. PMID:24235009

  8. Residual activity induced by ion bombardment on insulating samples

    NASA Astrophysics Data System (ADS)

    Shubeita, S. M.; dos Santos, C. E. I.; Filho, J. L. R.; Giulian, R.; Meira, L.; Silva, P. R.; Amaral, L.; Dias, J. F.; Yoneama, M. L.

    2005-10-01

    In this work we investigate some properties of the residual activity induced by protons impinging on quartz, mylar and other insulating materials. In particular, we discuss the time constant related to the decay of the emitted radiation after the primary ion beam is turned off. This radiation includes a continuum of bremsstrahlung and, in some cases, characteristic X-rays induced in the process as well. In general, the results indicate the presence of two time constants in the decaying process. Moreover, it appears that the residual activity has a strong dependence on the material specifications and on the conditions of the surface under bombardment. A simple mechanism for this process is suggested.

  9. Exploring the Early Bombardment of the Inner Solar System

    NASA Astrophysics Data System (ADS)

    Bottke, W.

    2014-04-01

    The early bombardment history of the Inner Solar System is recorded in a number of interesting places (e.g., the surprisingly high abundance of highly siderophile abundances found in the Earth, Moon, and Mars, the observed impact basins found on Mercury, the Moon and Mars, various properties of main belt asteroids and meteorites, etc.). To date, two dominant scenarios have been used to explain these constraints: (i) most impacts came from the tail end of a monotonically-decreasing impactor population created by planet formation processes, and (ii) most impacts were produced by a terminal cataclysm that caused a spike in the impactor flux starting ~4 Gy ago. Interestingly, using numerical studies linked to the available constraints, we find that both scenarios are needed to explain observations. For (i), we will show that leftover planetesimals from the terrestrial planet region were long-lived enough to hit various worlds long after the end of core formation. The record left behind can be used in interesting ways to probe the nature of terrestrial planet formation. For (ii), we will explore new applications of the so-called Nice model, which provides a plausible dynamical mechanism capable of creating a spike of comets/asteroid impactors. Our results suggest that many "late heavy bombardment" impactors came from an unexpected source, and that they possibly continued to hit Earth, Venus, and Mars well after basin formation terminated on the Moon. Interestingly, the history of the Hadean Earth (ca. 4.0-4.5 billion years ago) may be closely linked to this bombardment. With few known rocks older than ~3.8 Ga, the main constraints from this era come from ancient submillimeter zircon grains. Using our bombardment model, we will argue that the surface of the Hadean Earth was widely reprocessed by impacts through mixing and heating of its uppermost layers. This model not only may explains the Pb-Pb age distribution of ancient zircons but also the absence of most early terrestrial rocks. We predict life originating in the Hadean would need to be both hardy and mobile enough to survive these extreme conditions.

  10. Non-fullerene acceptors: exciton dissociation with PTCDA versus C60.

    PubMed

    Dutton, Gregory J; Robey, Steven W

    2015-06-28

    Extensive development of new polymer and small molecule donors has helped produce a steady increase in the efficiency of organic photovoltaic (OPV) devices. However, OPV technology would also benefit from the introduction of non-fullerene acceptors. Unfortunately, efforts to replace fullerenes have typically led to significantly reduced efficiencies. A number of possible explanations for reduced efficiencies with non-fullerene acceptors compared to fullerene acceptors have been suggested, including the formation of unfavorable morphologies in non-fullerene systems and/or favorable excitation/carrier delocalization in fullerenes. In addition, enhanced exciton dissociation associated with fundamental characteristics of the fullerene molecular electronic states has also been suggested. We used time-resolved two-photon photoemission (TR-2PPE) to directly compare exciton dissociation at interfaces between zinc phthalocyanine (ZnPc) interfaces and the non-fullerene acceptor, perylene tetracarboxylic dianhydride (PTCDA) versus dissociation measured at the analogous interface with C60, and thus help discriminate between these potential explanations. Exciton dissociation rates are comparable for phthalocyanine interfaces with both acceptors, allowing us to suggest a hierarchy for the importance of various effects producing higher efficiencies with fullerene acceptors. PMID:26027544

  11. Colloidal structure and stabilization mechanism of aqueous solutions of unmodified fullerene C{sub 60}

    SciTech Connect

    Khokhryakov, A. A., E-mail: art@nf.jinr.ru; Kyzyma, O. A. [Joint Institute for Nuclear Research (Russian Federation); Bulavin, L. A. [Shevchenko National University (Ukraine); Len, A. [Research Institute for Solid-State Physics and Optics (Hungary); Avdeev, M. V.; Aksenov, V. L. [Joint Institute for Nuclear Research (Russian Federation)

    2007-05-15

    Despite the inability of fullerenes to be directly dissolved in water, there are methods for preparing stable dispersions of fullerenes in water without any particular modifications of the fullerene or addition of stabilizers. The colloidal properties of such systems prepared by replacing the solvent and structural changes in them during coagulation have been studied. The coagulation dynamics has been investigated by spectroscopy and small-angle neutron scattering. The results obtained confirm the colloidal nature of such systems. During coagulation, particles retain a large volume of water around them, an indication of interaction between fullerene and water during solution stabilization.

  12. Effect of Self-Assembly of Fullerene Nano-Particles on Lipid Membrane

    PubMed Central

    Zhang, Saiqun; Mu, Yuguang; Zhang, John Z. H.; Xu, Weixin

    2013-01-01

    Carbon nanoparticles can penetrate the cell membrane and cause cytotoxicity. The diffusion feature and translocation free energy of fullerene through lipid membranes is well reported. However, the knowledge on self-assembly of fullerenes and resulting effects on lipid membrane is poorly addressed. In this work, the self-assembly of fullerene nanoparticles and the resulting influence on the dioleoylphosphtidylcholine (DOPC) model membrane were studied by using all-atom molecular dynamics simulations with explicit solvents. Our simulation results confirm that gathered small fullerene cluster can invade lipid membrane. Simulations show two pathways: 1) assembly process is completely finished before penetration; 2) assembly process coincides with penetration. Simulation results also demonstrate that in the membrane interior, fullerene clusters tend to stay at the position which is 1.0 nm away from the membrane center. In addition, the diverse microscopic stacking mode (i.e., equilateral triangle, tetrahedral pentahedral, trigonal bipyramid and octahedron) of these small fullerene clusters are well characterized. Thus our simulations provide a detailed high-resolution characterization of the microscopic structures of the small fullerene clusters. Further, we found the gathered small fullerene clusters have significant adverse disturbances to the local structure of the membrane, but no great influence on the global integrity of the lipid membrane, which suggests the prerequisite of high-content fullerene for cytotoxicity. PMID:24204827

  13. ETFE polymer bombarded with 1 MeV proton

    NASA Astrophysics Data System (ADS)

    Parada, M. A.; de Almeida, A.; Muntele, I.; Muntele, C.; Delalez, N.; Ila, D.

    2005-12-01

    The ethylenetetrafluoroethylene (ETFE) is a polymer formed by alternating ethylene and tetrafluoroethylene segments. It has high impact resistance and useful mechanical properties. ETFE can be used as components of pumps, valves, tie wraps, and electrical components. It can also be applied in the field of medical physics as intra venous catheters and as radiation dosimeter. When a material is exposed to the ionizing radiation, it suffers damage that depends on the type, energy and intensity of the radiation. In order to determine the radiation damage mechanism, ETFE films were bombarded with 1 MeV protons to the fluence between 1 × 10 11 and 1 × 10 16 protons/cm 2 and the chemical species emitted during the bombardment were measured with residual gas analysis (RGA) and show that HF gas is the entity preferentially emitted. Optical absorption photospectrometry (OAP) and attenuated total reflectometry fourier transform infrared (ATR-FTIR) shows quantitative chemical evidence of the damage. Our results show that damage is detectable at low proton fluence, but damage that can compromise the application in dosimetry occurs only for fluence greater than 10 14 protons/cm 2.

  14. Photoabsorption spectrum of the Xe@C60 endohedral fullerene

    NASA Astrophysics Data System (ADS)

    Chen, Zhifan; Msezane, A. Z.

    2012-07-01

    Photoabsorption spectrum of the Xe@C60 endohedral fullerene has been studied using the time-dependent-density-functional-theory (TDDFT), which represents the dynamical polarizability of an interacting electron system by an off-diagonal matrix element of the resolvent of the Liouvillian superoperator and solves the problem with the Lanczos algorithm. The method has been tested with the photoabsorption spectra for the free Xe atom and C60 fullerene. The result of the Xe atom encapsulated inside C60 confirms the three main peaks observed in the recent measurement in the energy region of the Xe 4 d giant resonance and indicates the possibility that the Auger decay of the Xe+ has been greatly suppressed if the ion is encapsulated inside C60. It is suggested to use the current theoretical result around 22 eV to check this possibility.

  15. Influence of Substrate on Crystallization in Polythiophene/fullerene Blends

    SciTech Connect

    C He; D Germack; J Kline; D Delongchamp; D Fischer; C Snyder; M Toney; J Kushmerick; L Richter

    2011-12-31

    The nanoscale morphology of the active layer in organic, bulk heterojunction (BHJ) solar cells is crucial to device performance. Often a combination of casting conditions and post deposition thermal treatment is used to optimize the morphology. In general, the development of microscopic crystals is deleterious, as the exciton diffusion length is {approx}10 nm. We find that the microscopic crystallization behavior in polythiophene/fullerene blends is strongly influenced by the substrate on which the BHJ is cast. With a silicon oxide substrate, the crystal nucleation density is high and significant crystallization occurs at a temperature of 140 C. On more hydrophobic substrates, significantly higher temperatures are required for observable crystallization. This difference is attributed to the interfacial segregation of the PCBM, controlled by the substrate surface energy. The substrate dependence of crystallization has significant implications on the fullerene crystal growth mechanisms and practical implications for device studies.

  16. Charge transfer in poly(3-octylthiophene) modified by fullerene derivative

    NASA Astrophysics Data System (ADS)

    Krinichnyi, V. I.; Demianets, Y. N.; Mironova, S. A.

    2008-06-01

    Magnetic, relaxation, and electronic dynamic parameters of paramagnetic centers stabilized in an initial and fullerene-modified poly(3-octylthiophene) (P3OT) were studied at the 3-cm (9.7 GHz) waveband EPR in wide (77-320 K) temperature region. Both the systems demonstrate sum spectrum of localized and mobile polarons, whose contribution depends on polymer treatment. Both spin susceptibility and spin-spin relaxation rate were shown to govern by dipole-dipole interaction of the mobile polarons. The spin-lattice and spin-spin relaxation times were determined separately by using the steady-state saturation method. It was shown that the treatment of the P3OT sample with fullerene molecules leads to the decrease in activation energy of spin susceptibility, dipole-dipole interaction, and interchain diffusion. This is accompanied by the acceleration of spin relaxation and increase in the system dimensionality.

  17. The electronic structures of graphite and fullerene, and their compounds

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shinji; Okino, Fujio; Touhara, Hidekazu; Liu, Ning; Nakajima, Toyohisa

    We report results of first-principles molecular orbital calculations on model clusters of graphite (C24), alkali graphite intercalation compounds (MC48: M = Li, Na, K, Rb, Cs), fullerene (C60), and fluorinated fullerenes (C60Fx,: X = 18, 36, 48). The calculated partial densities of states (pDOS) are compared with measured x-ray absorption near edge structure (XANES) spectra, x-ray photoelectron spectra (XPS), x-ray emission spectra (XES), and ultraviolet photoelectron spectra (UPS). In the case of graphite and its compounds, the calculated pDOS well reproduce features of the observed XANES and UPS spectra. The calculated pDOS and the observed XPS, UPS and XANES of C60Fx: (x = 0, 36, 48) are also in satisfactory accordance.

  18. Organic photodetectors based on phthalocyanine and fullerenes: dielectric properties.

    PubMed

    Sahu, Satyajit; Pal, Amlan J

    2009-01-01

    Fabrication and characterization of organic photodetectors based on copper phthalocyanine and fullerenes are presented. We study current-voltage and impedance characteristics of the devices under dark and varied illumination conditions. The current-voltage characteristics in the reverse bias show little or no dark current and large photocurrent. The results show that photocurrent in the devices is associated with a decrease in bulk resistance and an increase in dielectric constant of the active material. PMID:19441333

  19. Ultrafast spectroscopic investigation of a fullerene poly(3-hexylthiophene) dyad

    Microsoft Academic Search

    Natalie Banerji; Jason Seifter; Mingfeng Wang; Eric Vauthey; Fred Wudl; Alan J. Heeger

    2011-01-01

    We present the femtosecond spectroscopic investigation of a covalently linked dyad, PCB-P3HT, formed by a segment of the conjugated polymer P3HT (regioregular poly(3-hexylthiophene)) that is end capped with the fullerene derivative PCB ([6,6]-phenyl-C61-butyric acid ester), adapted from PCBM. The fluorescence of the P3HT segment in tetrahydrofuran (THF) solution is reduced by 64% in the dyad compared to a control compound

  20. New fullerene-based mixed materials: Synthesis and characterization

    Microsoft Academic Search

    D. McBranch; R. Kohlman; V. Klimov; M. Grigorova; X. Shi; L. Smilowitz; B. R. Mattes; H. Wang; F. Wudl

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors present results of broadband femtosecond transient absorption and broadband nanosecond optical limiting studies of Cââ and derivatized Cââ. They have investigated both solutions and solid-state mixed materials (sol-gel glass hosts doped with fullerene guests). They show

  1. Linear and nonlinear optical properties of [60]fullerene derivatives.

    PubMed

    Loboda, O; Zale?ny, R; Avramopoulos, A; Luis, J-M; Kirtman, B; Tagmatarchis, N; Reis, H; Papadopoulos, M G

    2009-02-12

    Using a wide variety of quantum-chemical methods we have analyzed in detail the linear and non-linear optical properties of [60]fullerene-chromophore dyads of different electron-donor character. The dyads are composed of [60]fullerene covalently linked with 2,1,3-benzothiadiazole and carbazole derivatives. Linear scaling calculations of molecular (hyper)polarizabilities were performed using wave function theory as well as density functional theory (DFT). Within the former approach, we used both semiempirical (PM3) and ab initio (Hartree-Fock and second-order Møller-Plesset perturbation theory) methods. Within the latter approach only the recently proposed long-range (LRC) schemes successfully avoid a large overshoot in the value obtained for the first hyperpolarizability (?). Calculations on model fullerene derivatives establish a connection between this overshoot and the electron-donating capability of the substituent. Substitution of 2,1,3-benzothiadiazole by the triphenylamine group significantly increases the electronic first and second hyperpolarizabilities as well as the two-photon absorption cross section. For [60]fullerene-chromophore dyads we have, additionally, observed that the double harmonic vibrational contribution to the static beta is much larger than its electronic counterpart. The same is true for the dc-Pockels ? as compared to the static electronic value, although the vibrational term is reduced in magnitude; for the intensity-dependent refractive index the vibrational and electronic terms are comparable. A nuclear relaxation treatment of vibrational anharmonicity for a model fulleropyrrolidine molecule yields a first-order contribution that is substantially more important than the double harmonic term for the static ?. PMID:19146443

  2. Organic photovoltaic cells based on conjugated polymer\\/fullerene composites

    Microsoft Academic Search

    Heejoo Kim; Jin Young Kim; Kwanghee Lee; Youngeup Jin; Hongsuk Suh

    2001-01-01

    We fabricated organic photovoltaic cells using poly[2-methoxy,5-(2?-ethylhexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) and fullerene derivative, [6,6]-phenylen C61-butyric acid methyl ester (PCBM), composites with various concentrations of the PCBM. The devices exhibit photoluminescence quenching and enhancement in photovoltaic response with increasing PCBM concentrations, both of which are associated with the photoinduced charge transfer characteristics of these materials. We also investigate the PCBM concentration dependence on

  3. Top-down formation of fullerenes in the interstellar medium

    NASA Astrophysics Data System (ADS)

    Berné, O.; Montillaud, J.; Joblin, C.

    2015-05-01

    Fullerenes have recently been detected in various circumstellar and interstellar environments, raising the question of their formation pathway. It has been proposed that they can form at the low densities found in the interstellar medium by the photo-chemical processing of large polycyclic aromatic hydrocarbons (PAHs). Following our previous work on the evolution of PAHs in the NGC 7023 reflection nebula, we evaluate, using photochemical modelling, the possibility that the PAH C66H20 (i.e. circumovalene) can lead to the formation of the C60 fullerene upon irradiation by ultraviolet photons. The chemical pathway involves full dehydrogenation of C66H20, folding into a floppy closed cage and shrinking of the cage by loss of C2 units until it reaches the symmetric C60 molecule. At 10'' from the illuminating star and with realistic molecular parameters, the model predicts that 100% of C66H20 is converted into C60 in ~105 yr, a timescale comparable to the age of the nebula. Shrinking appears to be the kinetically limiting step of the whole process. Hence, PAHs larger than C66H20 are unlikely to contribute significantly to the formation of C60, while PAHs containing between 60 and 66 C atoms should contribute to the formation of C60 with shorter timescales, and PAHs containing fewer than 60 C atoms will be destroyed. Assuming a classical size distribution for the PAH precursors, our model predicts that absolute abundances of C60 are up to several 10-4 of the elemental carbon, that is, less than a percent of the typical interstellar PAH abundance, which is consistent with observational studies. According to our model, once formed, C60 can survive much longer (> 107 yr for radiation fields below G0 = 104) than other fullerenes because of the remarkable stability of the C60 molecule at high internal energies. Hence, a natural consequence is that C60 is more abundant than other fullerenes in highly irradiated environments.

  4. Single or functionalized fullerenes interacting with heme group

    SciTech Connect

    Costa, Wallison Chaves; Diniz, Eduardo Moraes, E-mail: eduardo.diniz@ufma.br [Departamento de Física, Universidade Federal do Maranhão, Avenida dos Portugueses, 1966, CEP 65080-805, São Luís - MA (Brazil)

    2014-09-15

    The heme group is responsible for iron transportation through the bloodstream, where iron participates in redox reactions, electron transfer, gases detection etc. The efficiency of such processes can be reduced if the whole heme molecule or even the iron is somehow altered from its original oxidation state, which can be caused by interactions with nanoparticles as fullerenes. To verify how such particles alter the geometry and electronic structure of heme molecule, here we report first principles calculations based on density functional theory of heme group interacting with single C{sub 60} fullerene or with C{sub 60} functionalized with small functional groups (?CH{sub 3}, ?COOH, ?NH{sub 2}, ?OH). The calculations shown that the system heme + nanoparticle has a different spin state in comparison with heme group if the fullerene is functionalized. Also a functional group can provide a stronger binding between nanoparticle and heme molecule or inhibit the chemical bonding in comparison with single fullerene results. In addition heme molecule loses electrons to the nanoparticles and some systems exhibited a geometry distortion in heme group, depending on the binding energy. Furthermore, one find that such nanoparticles induce a formation of spin up states in heme group. Moreover, there exist modifications in density of states near the Fermi energy. Although of such changes in heme electronic structure and geometry, the iron atom remains in the heme group with the same oxidation state, so that processes that involve the iron might not be affected, only those that depend on the whole heme molecule.

  5. Computational studies on non-covalent interactions of carbon and boron fullerenes with graphene.

    PubMed

    Manna, Arun K; Pati, Swapan K

    2013-06-24

    First-principles DFT calculations are carried out to study the changes in structures and electronic properties of two-dimensional single-layer graphene in the presence of non-covalent interactions induced by carbon and boron fullerenes (C60, C70, C80 and B80). Our study shows that larger carbon fullerene interacts more strongly than the smaller fullerene, and boron fullerene interacts more strongly than that of its carbon analogue with the same nuclearity. We find that van der Waals interactions play a major role in governing non-covalent interactions between the adsorbed fullerenes and graphene. Moreover, a greater extent of van der Waals interactions found for the larger fullerenes, C80 and B80, relative to smaller C60, and consequently, results in higher stabilisation. We find a small amount of electron transfer from graphene to fullerene, which gives rise to a hole-doped material. We also find changes in the graphene electronic band structures in the presence of these surface-decorated fullerenes. The Dirac cone picture, such as that found in pristine graphene, is significantly modified due to the re-hybridisation of graphene carbon orbitals with fullerenes orbitals near the Fermi energy. However, all of the composites exhibit perfect conducting behaviour. The simulated absorption spectra for all of the graphene-fullerene hybrids do not exhibit a significant change in the absorption peak positions with respect to the pristine graphene absorption spectrum. Additionally, we find that the hole-transfer integral between graphene and C60 is larger than the electron-transfer integrals and the extent of these transfer integrals can be significantly tuned by graphene edge functionalisation with carboxylic acid groups. Our understanding of the non-covalent functionalisation of graphene with various fullerenes would promote experimentalists to explore these systems, for their possible applications in electronic and opto-electronic devices. PMID:23616400

  6. Atom penetration from a thin film into the substrate during sputtering by polyenergetic Ar{sup +} ion beam with mean energy of 9.4 keV

    SciTech Connect

    Kalin, B.A.; Gladkov, V.P.; Volkov, N.V.; Sabo, S.E. [Moscow Engineering Physics Inst. (Russian Federation)

    1995-12-31

    Penetration of alien atoms (Be, Ni) into Be, Al, Zr, Si and diamond was investigated under Ar{sup +} ion bombardment of samples having thermally evaporated films of 30--50 nm. Sputtering was carried out using a wide energy spectrum beam of Ar{sup +} ions of 9.4 keV to dose D = 1 {times} 10{sup 16}--10{sup 19} ion/cm{sup 2}. Implanted atom distribution in the targets was measured by Rutherford backscattering spectrometry (RBS) of H{sup +} and He{sup +} ions with energy of 1.6 MeV as well as secondary ion mass-spectrometry (SIMS). During the bombardment, the penetration depth of Ar atoms increases with dose linearly. This depth is more than 3--20 times deeper than the projected range of bombarding ions and recoil atoms. This is a deep action effect. The analysis shows that the experimental data for foreign atoms penetration depth are similar to the data calculated for atom migration through the interstitial site in a field of internal (lateral) compressive stresses created in the near-surface layer of the substrate as a result of implantation. Under these experimental conditions atom ratio r{sub i}/r{sub m} (r{sub i} -- radius of dopant, r{sub m} -- radius target of substrate) can play a principal determining role.

  7. Fullerene derivatives as electron acceptors for organic photovoltaic cells.

    PubMed

    Mi, Dongbo; Kim, Ji-Hoon; Kim, Hee Un; Xu, Fei; Hwang, Do-Hoon

    2014-02-01

    Energy is currently one of the most important problems humankind faces. Depletion of traditional energy sources such as coal and oil results in the need to develop new ways to create, transport, and store electricity. In this regard, the sun, which can be considered as a giant nuclear fusion reactor, represents the most powerful source of energy available in our solar system. For photovoltaic cells to gain widespread acceptance as a source of clean and renewable energy, the cost per watt of solar energy must be decreased. Organic photovoltaic cells, developed in the past two decades, have potential as alternatives to traditional inorganic semiconductor photovoltaic cells, which suffer from high environmental pollution and energy consumption during production. Organic photovoltaic cells are composed of a blended film of a conjugated-polymer donor and a soluble fullerene-derivative acceptor sandwiched between a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-coated indium tin oxide positive electrode and a low-work-function metal negative electrode. Considerable research efforts aim at designing and synthesizing novel fullerene derivatives as electron acceptors with up-raised lowest unoccupied molecular orbital energy, better light-harvesting properties, higher electron mobility, and better miscibility with the polymer donor for improving the power conversion efficiency of the organic photovoltaic cells. In this paper, we systematically review novel fullerene acceptors synthesized through chemical modification for enhancing the photovoltaic performance by increasing open-circuit voltage, short-circuit current, and fill factor, which determine the performance of organic photovoltaic cells. PMID:24749413

  8. Predicting morphologies of solution processed polymer:fullerene blends.

    PubMed

    Kouijzer, Sandra; Michels, Jasper J; van den Berg, Mauricio; Gevaerts, Veronique S; Turbiez, Mathieu; Wienk, Martijn M; Janssen, René A J

    2013-08-14

    The performance of solution processed polymer:fullerene thin film photovoltaic cells is largely determined by the nanoscopic and mesoscopic morphology of these blends that is formed during the drying of the layer. Although blend morphologies have been studied in detail using a variety of microscopic, spectroscopic, and scattering techniques and a large degree of control has been obtained, the current understanding of the processes involved is limited. Hence, predicting the optimized processing conditions and the corresponding device performance remains a challenge. We present an experimental and modeling study on blends of a small band gap diketopyrrolopyrrole-quinquethiophene alternating copolymer (PDPP5T) and [6,6]-phenyl-C71-butyric acid methyl ester ([70]PCBM) cast from chloroform solution. The model uses the homogeneous Flory-Huggins free energy of the multicomponent blend and accounts for interfacial interactions between (locally) separated phases, based on physical properties of the polymer, fullerene, and solvent. We show that the spinodal liquid-liquid demixing that occurs during drying is responsible for the observed morphologies. The model predicts an increasing feature size and decreasing fullerene concentration in the polymer matrix with increasing drying time in accordance with experimental observations and device performance. The results represent a first step toward a predictive model for morphology formation. PMID:23863101

  9. Continuous symmetry of C60 fullerene and its derivatives.

    PubMed

    Sheka, E F; Razbirin, B S; Nelson, D K

    2011-04-21

    Conventionally, the I(h) symmetry of fullerene C(60) is accepted, which is supported by numerous calculations. However, this conclusion results from the consideration of the molecule electron system, of its odd electrons in particular, in a closed-shell approximation without taking the electron spin into account. Passing to the open-shell approximation has led to both the energy and the symmetry lowering up to C(i). Seemingly contradicting to a high-symmetry pattern of experimental recording, particularly concerning the molecule electronic spectra, the finding is considered in this Article from the continuous symmetry viewpoint. Exploiting continuous symmetry measure and continuous symmetry level approaches, it was shown that formal C(i) symmetry of the molecule is by 99.99% I(h). A similar continuous symmetry analysis of the fullerene monoderivatives gives a reasonable explanation of a large variety of their optical spectra patterns within the framework of the same C(1) formal symmetry exhibiting a strong stability of the C(60) skeleton. TOC color pictures present chemical portrait of C(60) in terms of atomic chemical susceptibility (Sheka, E. Fullerenes: Nanochemistry, Nanomagnetism, Nanomedicine, Nanophotonics; CRC Press: Taylor and Francis Group, Boca Raton, 2011). PMID:21449547

  10. [70]fullerene-based materials for organic solar cells.

    PubMed

    Troshin, Pavel A; Hoppe, Harald; Peregudov, Alexander S; Egginger, Martin; Shokhovets, Sviatoslav; Gobsch, Gerhard; Sariciftci, N Serdar; Razumov, Vladimir F

    2011-01-17

    The synthesis, characterization and photovoltaic study of two novel derivatives of [70]fullerene, phenyl-C??-propionic acid propyl ester ([70]PCPP) and phenyl-C??-propionic acid butyl ester ([70]PCPB), are reported. [70]PCPP and [70]PCPB outperform the conventional material (6,6)-phenyl-C??-butyric acid methyl ester ([70]PCBM) in solar cells based on poly(2-methoxy-5-{3',7'-dimethyloctyloxy}-p-phenylene vinylene) (MDMO-PPV) as a donor polymer using chlorobenzene (CB) or dichlorobenzene (DCB) as solvents. AFM data suggest that improvement of the device efficiency should be attributed to the increased phase compatibility between the novel C?? derivatives and the polymer matrix. [70]PCPP and [70]PCBM showed more or less equally high performances in solar cells comprising poly(3-hexylthiophene) (P3HT) as a donor polymer. Optical modeling revealed that the application of [70]fullerene derivatives as acceptor materials in P3HT-based bulk heterojunction solar cells might give approximately 10?% higher short circuit current densities than using C??-based materials such as [60]PCBM. The high solubility of [70]PCPP and [70]PCPB and their good compatibility with the donor polymers suggest these fullerene derivatives as promising electron acceptor materials for use in efficient bulk heterojunction organic solar cells. PMID:21226221

  11. Alternative approaches to onion-like icosahedral fullerenes.

    PubMed

    Janner, A

    2014-03-01

    The fullerenes of the C60 series (C60, C240, C540, C960, C1500, C2160 etc.) form onion-like shells with icosahedral Ih symmetry. Up to C2160, their geometry has been optimized by Dunlap & Zope from computations according to the analytic density-functional theory and shown by Wardman to obey structural constraints derived from an affine-extended Ih group. In this paper, these approaches are compared with models based on crystallographic scaling transformations. To start with, it is shown that the 56 symmetry-inequivalent computed carbon positions, approximated by the corresponding ones in the models, are mutually related by crystallographic scalings. This result is consistent with Wardman's remark that the affine-extension approach simultaneously models different shells of a carbon onion. From the regularities observed in the fullerene models derived from scaling, an icosahedral infinite C60 onion molecule is defined, with shells consisting of all successive fullerenes of the C60 series. The structural relations between the C60 onion and graphite lead to a one-parameter model with the same Euclidean symmetry P63mc as graphite and having a c/a = ?(2) ratio, where ? = 1.618… is the golden number. This ratio approximates (up to a 4% discrepancy) the value observed in graphite. A number of tables and figures illustrate successive steps of the present investigation. PMID:24572318

  12. New fullerene-based mixed materials: Synthesis and characterization

    SciTech Connect

    McBranch, D.; Kohlman, R.; Klimov, V.; Grigorova, M.; Shi, X.; Smilowitz, L.; Mattes, B.R. [Los Alamos National Lab., NM (US); Wang, H.; Wudl, F. [Univ. of California, Santa Barbara, CA (US)

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors present results of broadband femtosecond transient absorption and broadband nanosecond optical limiting studies of C{sub 60} and derivatized C{sub 60}. They have investigated both solutions and solid-state mixed materials (sol-gel glass hosts doped with fullerene guests). They show that derivatized fullerenes provide enhanced solubility and processability, with a ground-state absorption extended into the infrared compared with C{sub 60}. They have extensively studied both the dynamic optical response and the excited-state absorption cross sections of solutions and solids for multiple wavelengths in the visible to near infrared. Wavelength-dependent studies show that the optical limiting response improves monotonically at longer wavelengths, demonstrating broadband limiting in all 6,6 mono-adducts and neat C{sub 60}. The authors report new approaches to processing sol-gel glass/fullerene composites to improve the optical limiting performance of solid-state materials to approach the response of solution limiters.

  13. Preparation of fluorescent mesoporous hollow silica-fullerene nanoparticles via selective etching for combined chemotherapy and photodynamic therapy.

    PubMed

    Yang, Yannan; Yu, Meihua; Song, Hao; Wang, Yue; Yu, Chengzhong

    2015-07-28

    Well-dispersed mesoporous hollow silica-fullerene nanoparticles with particle sizes of ?50 nm have been successfully prepared by incorporating fullerene molecules into the silica framework followed by a selective etching method. The fabricated fluorescent silica-fullerene composite with high porosity demonstrates excellent performance in combined chemo/photodynamic therapy. PMID:26041655

  14. AES Sputter Depth Profiling of Composition Microprofiles Induced by Low Energy Ion Bombardment in Binary Alloys

    E-print Network

    Zexian, Cao

    1 AES Sputter Depth Profiling of Composition Microprofiles Induced by Low Energy Ion Bombardment.5 Quantification of AES data for binary solids 26 2.6 Inelastic mean free path of electrons in iron silicides of composition depth profiles induced by ion bombardment 28 3.2 Sputter etching 31 3.3 Variation of AES signals

  15. The influence of ion bombardment intensity during deposition on nickel films microstructure

    Microsoft Academic Search

    N. Popovic; Z. Bogdanov; B. Goncic; S. Zec; Z. Rakocevic

    1999-01-01

    Nickel films were deposited from a vapour phase (e-gun source) onto amorphous glass substrates at room temperature during a simultaneous bombardment with nitrogen ions at low pressure (4 × 10?2 Pa). Under a constant partial pressure of nitrogen and negative substrate bias voltages the effect of bombardment intensity on the texture and morphology of Ni films (about 1 ?m) has

  16. Origin of the cataclysmic Late Heavy Bombardment period of the terrestrialplanets

    Microsoft Academic Search

    R. Gomes; H. F. Levison; K. Tsiganis; A. Morbidelli

    2005-01-01

    The petrology record on the Moon suggests that a cataclysmic spike in the cratering rate occurred ~700 million years after the planets formed; this event is known as the Late Heavy Bombardment (LHB). Planetary formation theories cannot naturally account for an intense period of planetesimal bombardment so late in Solar System history. Several models have been proposed to explain a

  17. Transgenic perennial ryegrass ( Lolium perenne) plants from microprojectile bombardment of embryogenic suspension cells

    Microsoft Academic Search

    Germán Spangenberg; Zeng-yu Wang; Xinli Wu; Jutta Nagel; Ingo Potrykus

    1995-01-01

    Transgenic forage-type perennial ryegrass (Lolium perenne L.) plants have been obtained by microprojectile bombardment of embryogenic suspension cells using a chimeric hygromycin phosphotransferase (hph) gene construct driven by rice Actl 5? regulatory sequences. Parameters for the bombardment of embryogenic suspension cultures with the particle inflow gun were partially optimized using transient expression assays of a chimeric ?-glucuronidase (gusA) gene driven

  18. An efficient particle bombardment system for the genetic transformation of asparagus ( Asparagus officinalis L.)

    Microsoft Academic Search

    Jose Luis Cabrera-Ponce; Liliana López; Nacyra Assad-Garcia; Consuelo Medina-Arevalo; Ana Maria Bailey; Luis Herrera-Estrella

    1997-01-01

    The microprojectile bombardment method was used to transfer DNA into embryogenic callus of asparagus (Asparagus officcinalis L.) and to produce stably transformed asparagus plants. Embryogenic callus, derived from UC 157 and UC72 asparagus cultivars, was bombarded with tungsten particles coated with plasmid DNA that contained genes encoding hygromycin phosphotransferase, phosphinothricin acetyl transferase and ß-glucuronidase. Putatively transformed calli were identified from

  19. Chemistry of acenes, [60]fullerenes, cyclacenes and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Pramanik, Chandrani

    2011-12-01

    In the present work, we studied the chemistries of acenes, cyclacenes, [60]fullerenes and CNTs. Acenes are well known organic semiconductors. Pentacene is a benchmark organic semiconductor due to low HOMO-LUMO gap and high charge carrier mobilities in its thin film. Its poor solubility and instability, however, limit its utility and overall cost effectiveness. We successfully synthesized several sulfur-functionalized acene derivatives that overcome these problems. However, we also encountered difficulties to aromatize some of these derivatives. To circumvent these problems, we studied some new synthetic routes to sulfur-functionalized anthracenes, pentacenes and nonacenes. Additionally, the electronic properties of substituted acenes were compared using high level DFT calculations. According to our unrestricted DFT calculations, significant spin characters associated with thio-substituted nonacenes are likely the reason for their instabilities and difficult syntheses. Our UV-Vis-NIR studies reveal acene characteristics in acene quinones and hydroxyacenes that are dissolved in concentrated sulfuric acid. Cyclacenes may be useful precursors to synthesize SWNTs with uniform dimensions. We explored the supramolecular assembly of a bis[60]fullerene adduct of a 2,3,9,10-tetrasubstituted pentacene as a method to produce a [24]cyclacene framework. To that end, we synthesized the bis[60]fullerene adduct of 2,3,9,10-tetraiodomethyl-6,13-diphenylpentacene. The synthesis of a cyclacene framework via intermolecular cycloaddition of bis[60]fullerene adducts requires further study. According to our unrestricted broken symmetry calculations for different functionalized [n]cyclacenes, HOMO-LUMO gaps and spin characters are impacted by the presence and location of alkylthio and/or arylthio functional groups on the [n]cyclacene skeleton. [60]Fullerene is known to form polysultone and chlorinated derivatives when treated with fuming sulfuric acid (FSA) and chlorosulfonic acid (CSA), respectively, at room temperature. Based on our preliminary study, we predict that MWNTs react with boiling CSA and they are unreactive toward boiling FSA. The CSA treated MWNTs showed less bundling and broken tips in their AFM and TEM images. We studied the self-assembly of carboxylated-SWNTs and polystyrene latex (PSL) particles on different substrates. We believe that carboxylated-SWNTs have stronger interactions with amino or carboxy terminated PSL than unsubstituted PSL particles. According to our SEM analysis, self-assembly of the nanocomposites is moderately substrate dependent.

  20. Fullerene Nanoparticles Exhibit Greater Retention in Freshwater Sediment than in Model Porous Media

    EPA Science Inventory

    Increasing production and use of fullerene-based nanomaterials underscore the need to determine their mobility in environmental transport pathways and potential ecological exposures. This study investigated the transport of two fullerenes (i.e., aqu/C(60) and water-soluble C(60) ...

  1. Computational studies of the binding mechanisms of fullerenes to human serum albumin.

    PubMed

    Li, Jinyu; Jiang, Lizhi; Zhu, Xiaolei

    2015-07-01

    Fullerene and its derivatives show promising prospects for applications in a vast array of biological systems. A key aspect concerning their biomedical applications is how they interact with proteins from molecular levels, which is still poorly understood. In the current study, we investigated the structural and thermodynamic basis of the interactions between two pharmacologically relevant fullerene derivatives and human serum albumin (HSA) using molecular docking, molecular dynamics simulations, and binding free energy calculations. Our results demonstrate that fullerenes steadily bind with HSA at the interfacial cavity formed by subdomains IIA and IIIA. In agreement with available experimental data, our simulations show that the global structure of HSA becomes more compact in the presence of fullerene, while local structural dynamics of the binding cavity behaves diversely depending on the chemical properties of bound fullerenes. Binding free energy calculations confirmed that the interactions between fullerenes and HSA are dominantly stabilized by van der Waals forces and they further allowed the identification of key residues involved in fullerene binding. The structural and energetic insights obtained from this work may help for the development of fullerene-based drug delivery devices and therapeutic agents with improved biological profile. PMID:26093686

  2. Phase equilibria in the system fullerene C 60 -hexane- o -xylene-dimethylformamide

    Microsoft Academic Search

    V. A. Keskinov; A. K. Pyartman; N. A. Charykov; O. V. Arapov; A. A. Pronkin; V. V. Lishchuk; V. V. Leonov

    2007-01-01

    Phase diagrams in ternary liquid systems hexane o-xylene DMF were studied at 298.15 333.15 K. Critical points in these systems were determined. The fullerene C60 distribution in the ternary liquid systems with constant and variable compositions of two organic phases was studied at variable\\u000a fullerene concentration.

  3. Testing for fullerenes in geologic materials: Oklo carbonaceous substances, Karelian shungites, Sudbury Black Tuff

    NASA Astrophysics Data System (ADS)

    Mossman, David; Eigendorf, Guenter; Tokaryk, Dennis; Gauthier-Lafaye, François; Guckert, Kristal D.; Melezhik, Victor; Farrow, Catharine E. G.

    2003-03-01

    Fullerenes have been reported from diverse geologic environments since their discovery in shungite from Karelian Russia. Our investigation is prompted by the presence of onionskin-like structures in some carbonaceous substances associated with the fossil nuclear fission reactors of Oklo, Gabon. The same series of extractions and the same instrumental techniques, laser desorption ionization and high-resolution mass spectroscopy (electron-impact mass spectroscopy), were employed to test for fullerenes in samples from three different localities: two sites containing putative fullerenes (Sudbury Basin and Russian Karelia) and one new location (Oklo, Gabon). We confirm the presence of fullerenes (C60 and C70) in the Black Tuff of the Onaping Formation impact breccia in the Sudbury Basin, but we find no evidence of fullerenes in shungite samples from various locations in Russian Karelia. Analysis of carbonaceous substances associated with the natural nuclear fission reactors of Oklo yields no definitive signals for fullerenes. If fullerenes were produced during sustained nuclear fission at Oklo, then they are present below the detection limit (˜100 fmol), or they have destabilized since formation. Contrary to some expectations, geologic occurrences of fullerenes are not commonplace.

  4. Importance of the Donor:Fullerene Intermolecular Arrangement for High-Efficiency Organic Photovoltaics

    E-print Network

    McGehee, Michael

    -accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solidImportance of the Donor:Fullerene Intermolecular Arrangement for High-Efficiency Organic of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis

  5. Polarons in linear chains of fullerenes V. A. Levashov, A. A. Remova, and V. R. Belosludova)

    E-print Network

    Levashov, Valentin

    Polarons in linear chains of fullerenes V. A. Levashov, A. A. Remova, and V. R. Belosludova´ksp. Teor. Fiz. 64, No. 8, 521­525 25 October 1996 Polaron states in linear chains of fullerenes are studied. A polaron band narrowing is examined. It is shown that the polymerization of C60 molecules in phase

  6. Solubilization of fullerene C60 in micellar solutions of different solubilizers.

    PubMed

    Torres, Vukosava Milic; Posa, Mihalj; Srdjenovic, Branislava; Simplício, Ana Luísa

    2011-01-01

    Fullerene (C(60)), the third carbon allotrope, is a classical engineered material with the potential application in biomedicine. However, extremely high hydrophobicity of fullerene hampers its direct biomedical evaluation and application. In this work, we investigated the solubilization of fullerene using 9 different solubility enhancers: Tween 20, Tween 60, Tween 80, Triton X-100, PVP, polyoxyethylene (10) lauryl ether, n-dodecyl trimethylammonium chloride, myristyl trimethylammonium bromide and sodium dodecyl sulphate and evaluated its antioxidant activity in biorelevant media. The presence of C(60) entrapped in surfactant micelles was confirmed by UV/VIS spectrometry. The efficacy of each modifier was evaluated by chemometric analysis using experimental data for investigating the relationship between solubilization and particle size distribution. Hierarchical clustering and principal component analysis was applied and showed that non-ionic surfactants provide better solubilization efficacy (>85%). A correlation was established (r=0.975) between the degree of solubilization and the surfactant structure. This correlation may be used for prediction of C(60) solubilization with non-tested solubility modifiers. Since the main potential biomedical applications of fullerene are based on its free radical quenching ability, we tested the antioxidant potential of fullerene micellar solutions. Lipid peroxidation tests showed that the micellar solutions of fullerene with Triton and polyoxyethylene lauryl ether kept high radical scavenging activity, comparable to that of aqueous suspension of fullerene and BHT. The results of this work provide a platform for further solubilization and testing of pristine fullerene and its hydrophobic derivatives in a biological benign environment. PMID:20828997

  7. Carbon Onion Films-Molecular Interactions of Multi-Layer Fullerenes Raed A. Alduhaileb,1

    E-print Network

    Ayres, Virginia

    Carbon Onion Films-Molecular Interactions of Multi-Layer Fullerenes Raed A. Alduhaileb,1 Virginia M-8550, Japan ABSTRACT The evolution of carbon onion structure from spherical to polyhedral is correlated-shell fullerenes, or carbon onions, are under investigation as a nano-property enabled solid lubricant

  8. Effects of high magnetic field on the morphology of carbon nanotubes and selective synthesis of fullerenes

    Microsoft Academic Search

    Haruo Yokomichi; Hiroyuki Sakima; Masaki Ichihara; Fumiko Sakai; Kikuo Itoh; Naoki Kishimoto

    1999-01-01

    Carbon nanotubes and fullerenes were synthesized by arc discharge in a He gas atmosphere under a high magnetic field up to 10 T. Morphology and the yield of these nanotubes were investigated by scanning electron microscopy and transmission electron microscopy (TEM). The yield and type of fullerenes were also evaluated by ultraviolet visual spectroscopy. TEM images revealed that thin collapsed

  9. Self-Assembled Fullerene-Derivative Monolayers on a Gold Substrate Using Phenanthroline-Au Interactions

    E-print Network

    Tao, Nongjian

    Self-Assembled Fullerene-Derivative Monolayers on a Gold Substrate Using Phenanthroline-ordered monolayers.5a A much less explored area in the field of self-assembly is the use of bipyridine (bpy of the final product, phenanthrolyl[60]fullerene, compound 1, in a 43% isolated yield. Spontaneous self-assembly

  10. Temperature Dependence of Solubility of Light Fullerenes in Some Essential Oils

    Microsoft Academic Search

    Konstantin N. Semenov; Nikolay A. Charykov; Viktor I. Namazbaev; Nikolay I. Alekseyev; Ekaterina G. Gruzinskaya; Viktor N. Postnov; Olga A. Krokhina

    2011-01-01

    Polythermal solubility of individual light fullerenes (C60, C70) and industrial fullerene mixture (60% ?60, 39% ?70, 1% ?76–90) in some essential oils (e.g., essential oil of coriander, cypress, hazel, carnation, cade (leafage), cade (wood), cedar) is investigated. Temperature dependences of solubility are presented and characterized.

  11. Changes in Agglomeration of Fullerenes During Ingestion and Excretion in Thamnocephalus Platyurus

    EPA Science Inventory

    The crustacean Thamnocephalus platyurus was exposed to aqueous suspensions of fullerenes C60 and C70. Aqueous fullerene suspensions were formed by stirring C60 and C70 as received from a commercial vendor in deionized water (termed aqu/C60 and aqu/C70) for approximately 100 d. Th...

  12. Computation of the ultraviolet absorption and electron inelastic scattering cross section of multishell fullerenes

    Microsoft Academic Search

    A. A. Lucas; L. Henrard; Ph. Lambin

    1994-01-01

    We develop a model in which the ultraviolet dielectric tensor of planar graphite is transported to the spherical geometry of a nanoscale multishell fullerene with a central cavity. This is accomplished by assigning to every point of the multishell fullerene a local dielectric tensor identical to that of graphite with its c axis aligned along the local radial direction. The

  13. Fullerenes as carriers of extinction, diffuse interstellar bands and anomalous microwave emission

    Microsoft Academic Search

    Susana Iglesias-Groth

    2008-01-01

    According to semiempirical models, photoabsorption by fullerenes (single and multishell) could explain the shape, width and peak energy of the most prominent feature of the interstellar absorption, the UV bump at 2175 Å. Other weaker transitions are predicted in the optical and near-infrared providing a potential explanation for diffuse interstellar bands. In particular, we find that several fullerenes could contribute

  14. From fullerenes to nanocrystals and nanocrystal arrays: Novel preparation and characterization methods

    Microsoft Academic Search

    Igor Vezmar

    1998-01-01

    The success of cluster physics and chemistry and the macroscopic isolation of fullerenes motivated the research of nanometer-size from assemblies based on other elements. In this work an alternative fullerene generation method, utilizing the annealing of an all-carbon precursor formed in the reaction of halocarbons with alkali metals, has been demonstrated. Furthermore, a novel method of nanocrystal processing has been

  15. Water-soluble fullerene materials for bioapplications: photoinduced reactive oxygen species generation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The photoinduced reactive oxygen species (ROS) generation from several water-soluble fullerenes was examined. Macromolecular or small molecular water-soluble fullerene complexes/derivatives were prepared and their 1O2 and O2•- generation abilities were evaluated by EPR spin-trapping methods. As a r...

  16. Navya Biomedical Technologies, LLC Developing Fullerenes to Image and Destroy Tumors

    E-print Network

    Jawitz, James W.

    Navya Biomedical Technologies, LLC Developing Fullerenes to Image and Destroy Tumors Navya, and commercializes novel proprietary polyhydroxy fullerenes to non-invasively image and destroy solid tumors into the tumor, which is then exposed to an in- frared laser. This treatment has shown a decrease in tumor size

  17. Energetic ion (>~50kev) and electron (>~40kev) bursts observed by ULYSSES near Jupiter

    Microsoft Academic Search

    G. C. Anagnostopoulos; A. Aggelis; I. Karanikola; P. K. Marhavilas

    2001-01-01

    A careful analysis of data collected by the HISCALE experiment on board Ulysses suggests that the quasi-periodic (Q-P) modulation of several or tens of minutes in flux and\\/or anisotropy\\/spectral observations is an almost permanent characteristic of the energetic (>~50 keV) ion population in the outer and the high latitude middle magnetosphere of Jupiter. In most cases a periodicity of ~5-20

  18. Adverse effects of fullerenes (nC60) spiked to sediments on Lumbriculus variegatus (Oligochaeta).

    PubMed

    Pakarinen, K; Petersen, E J; Leppänen, M T; Akkanen, J; Kukkonen, J V K

    2011-12-01

    Effects of fullerene-spiked sediment on a benthic organism, Lumbriculus variegatus (Oligochaeta), were investigated. Survival, growth, reproduction, and feeding rates were measured to assess possible adverse effects of fullerene agglomerates produced by water stirring and then spiked to a natural sediment. L. variegatus were exposed to 10 and 50 mg fullerenes/kg sediment dry mass for 28 d. These concentrations did not impact worm survival or reproduction compared to the control. Feeding activities were slightly decreased for both concentrations indicating fullerenes' disruptive effect on feeding. Depuration efficiency decreased in the high concentration only. Electron and light microscopy and extraction of the worm fecal pellets revealed fullerene agglomerates in the gut tract but not absorption into gut epithelial cells. Micrographs also indicated that 16% of the epidermal cuticle fibers of the worms were not present in the 50 mg/kg exposures, which may make worms susceptible to other contaminants. PMID:21852027

  19. Optical limiting and excited-state absorption in fullerene solutions and doped glasses

    NASA Astrophysics Data System (ADS)

    McBranch, Duncan W.; Smilowitz, Laura B.; Klimov, Victor I.; Koskelo, Aaron C.; Robinson, Jeanne M.; Mattes, Benjamin R.; Hummelen, Jan C.; Wudl, Fred; Withers, James C.; Borrelli, Nicholas F.

    1995-12-01

    We report the ground-state and excited-state optical absorption spectra in the visible and near infrared for several substituted fullerenes and higher fullerenes in toluene solutions. Based on these measurements, broadband predictions of the optical limiting performance of these molecules can be deduced. These predictions are then tested in the wavelength range from 532 nm to 700 nm in intensity-dependent transmission measurements. We observe optical limiting in all fullerenes measured; higher fullerenes show the greatest potential for limiting in the near infrared (650 - 1000 nm), while substituted C60 shows optimal limiting in the visible (450 - 700 nm). We observe dramatically reduced limiting for solid forms of C60 (thin films and C60-doped porous glasses), indicating that efficient optical limiting in fullerenes requires true molecular solutions.

  20. The interactions of high-energy, highly-charged ions with fullerenes

    SciTech Connect

    Ali, R.; Berry, H.G.; Cheng, S. [and others

    1996-03-01

    In 1985, Robert Curl and Richard Smalley discovered a new form of carbon, the fullerene, C{sub 60}, which consists of 60 carbon atoms in a closed cage resembling a soccer ball. In 1990, Kritschmer et al. were able to make macroscopic quantities of fullerenes. This has generated intense activity to study the properties of fullerenes. One area of research involves collisions between fullerenes and atoms, ions or electrons. In this paper we describe experiments involving interactions between fullerenes and highly charged ions in which the center-of-mass energies exceed those used in other work by several orders of magnitude. The high values of projectile velocity and charge state result in excitation and decay processes differing significantly from those seen in studies 3 at lower energies. Our results are discussed in terms of theoretical models analogous to those used in nuclear physics and this provides an interesting demonstration of the unity of physics.

  1. Plasma properties in electron-bombardment ion thrusters

    NASA Technical Reports Server (NTRS)

    Matossian, J. N.; Beattie, J. R.

    1987-01-01

    The paper describes a technique for computing volume-averaged plasma properties within electron-bombardment ion thrusters, using spatially varying Langmuir-probe measurements. Average values of the electron densities are defined by integrating the spatially varying Maxwellian and primary electron densities over the ionization volume, and then dividing by the volume. Plasma properties obtained in the 30-cm-diameter J-series and ring-cusp thrusters are analyzed by the volume-averaging technique. The superior performance exhibited by the ring-cusp thruster is correlated with a higher average Maxwellian electron temperature. The ring-cusp thruster maintains the same fraction of primary electrons as does the J-series thruster, but at a much lower ion production cost. The volume-averaged predictions for both thrusters are compared with those of a detailed thruster performance model.

  2. Plasma properties in electron-bombardment ion thrusters

    SciTech Connect

    Matossian, J.N.; Beattie, J.R.

    1987-05-01

    The paper describes a technique for computing volume-averaged plasma properties within electron-bombardment ion thrusters, using spatially varying Langmuir-probe measurements. Average values of the electron densities are defined by integrating the spatially varying Maxwellian and primary electron densities over the ionization volume, and then dividing by the volume. Plasma properties obtained in the 30-cm-diameter J-series and ring-cusp thrusters are analyzed by the volume-averaging technique. The superior performance exhibited by the ring-cusp thruster is correlated with a higher average Maxwellian electron temperature. The ring-cusp thruster maintains the same fraction of primary electrons as does the J-series thruster, but at a much lower ion production cost. The volume-averaged predictions for both thrusters are compared with those of a detailed thruster performance model. 20 references.

  3. Spontaneous Pattern Formation on Ion Bombarded Si(001)

    SciTech Connect

    Chason, Eric; Erlebacher, Jonah, Aziz, Michael J.; Floro, Jerrold A.; Sinclair, Michael B.

    1999-04-26

    Pattern formation on surfaces undergoing low-energy ion bombardment is a common phenomenon. Here, a recently developed in situ spectroscopic light scattering technique was used to monitor periodic ripple evolution on Si(001) during Ar(+) sputtering. Analysis of the rippling kinetics indicated that under high flux sputtering at low temperatures the concentration of mobile species on the surface is saturated, and, surprisingly, is both temperature and ion flux independent. This is due to an effect of ion collision cascades on the concentration of mobile species. This new understanding of surface dynamics during sputtering allowed us to measure straighforwardly the activation energy for atomic migration on the surface to be 1.2+0.1 eV. The technique is generalizable to any material, including high temperature and insulating materials for which surface migration energies are notoriously difficult to measure.

  4. Optical radiation from regions downstream of mercury bombardment thrusters

    NASA Technical Reports Server (NTRS)

    Milder, N. L.; Sovey, J. S.

    1972-01-01

    A 0.5 meter focal length, plane grating monochromator was used to measure the radiance of spectral radiation emanating from regions downstream of a mercury bombardment thruster. The wavelength range investigated was 2800 A. This radiation was due primarily to the radiative decay of excited mercury atoms exhausted from the thruster. Radiance values ranged from 10 to the minus 11th power to 10 to the minus 9th power W/sq cm sr, varying with wavelength. For resonant radiation, the spectral radiance may exceed 10 to the minus 8th power W/sq cm sr. From such radiance measurements, it was concluded that the thruster background radiation should not interfere with the control functions of a star tracker viewing through the thruster exhaust, provided that the tracker is designed to operate with a sufficiently small field of view.

  5. Uses of ion bombardment in thin-film deposition

    SciTech Connect

    Erck, R.A.; Fenske, G.R.; Erdemir, A.

    1990-10-01

    Use of plasma- and ion-beam-modified surfaces and surface coatings in continually expanding in engineering disciplines. The purpose of these modifications and treatments is to impart favorable properties, such as wear resistance and lubricity, to the surfaces, while at the same time retaining the strength or toughness of the bulk materials. Energetic-ion bombardment can be used to modify the structural and chemical properties of surfaces or applied coatings. Ion-implantation has been used for many years, and recently, other surface-modification techniques, among them ion-beam mixing and ion-beam-assisted deposition, have attracted attention because they permit application of highly adherent lubricious and wear-resistant films. In this paper, ion-beam techniques are described from the viewpoint of ion-surface interactions, and some avenues for the engineering of tribological surfaces are presented. 100 refs., 4 figs.

  6. Cationization of organometallo carbonyl compounds by fast ion bombardment

    NASA Astrophysics Data System (ADS)

    Siuzdak, Gary; Wendeborn, Sebastian V.; Nicolaou, K. C.

    1992-01-01

    Organodicobalt, organochromium, and organomolybdenum carbonyl complexes have been studied using fast ion bombardment mass spectrometry. It has been found that the addition of cesium iodide to the liquid matrix, m-NBA, can significantly enhance the ability to observed the precursor ions of these organometallics through charge localization. In most cases the [M + Cs]+ ions were more abundant than the radical cations M-, the protonated molecules [M + H]+, or the sodium cationized molecules [M + Na]+ which were either unobservable or less intense than those treated with the cesium iodide salt solution. The decomposition of the compounds took place primarily through the successive loss of carbonyls from the radical cation with some carbonyl loss observed through the protonated and cationized species. The FAB matrix ions produced when cesium iodide was added to m-NBA also allowed for internal calibration.

  7. Universality of Spectator Fragmentation at Relativistic Bombarding Energies

    E-print Network

    A. Schuettauf; W. D. Kunze; A. Woerner; M. Begemann-Blaich; Th. Blaich; D. R. Bowman; R. J. Charity; A. Cosmo; A. Ferrero; C. K. Gelbke; C. Gross; W. C. Hsi; J. Hubele; G. Imme; I. Iori; P. Kreutz; G. J. Kunde; V. Lindenstruth; M. A. Lisa; W. G. Lynch; U. Lynen; M. Mang; T. Moehlenkamp; A. Moroni; W. F. J. Mueller; M. Neumann; B. Ocker; C. A. Ogilvie; G. F. Peaslee; J. Pochodzalla; G. Raciti; Th. Rubehn; H. Sann; C. Schwarz; W. Seidel; V. Serfling; L. G. Sobotka; J. Stroth; L. Stuttge; S. Tomasevic; W. Trautmann; A. Trzcinski; M. B. Tsang; A. Tucholski; G. Verde; C. W. Williams; E. Zude; B. Zwieglinski

    1996-06-18

    Multi-fragment decays of 129Xe, 197Au, and 238U projectiles in collisions with Be, C, Al, Cu, In, Au, and U targets at energies between E/A = 400 MeV and 1000 MeV have been studied with the ALADIN forward-spectrometer at SIS. By adding an array of 84 Si-CsI(Tl) telescopes the solid-angle coverage of the setup was extended to \\theta_lab = 16 degree. This permitted the complete detection of fragments from the projectile-spectator source. The dominant feature of the systematic set of data is the Z_bound universality that is obeyed by the fragment multiplicities and correlations. These observables are invariant with respect to the entrance channel if plotted as a function of Z_bound, where Z_bound is the sum of the atomic numbers Z_i of all projectile fragments with Z_i \\geq 2. No significant dependence on the bombarding energy nor on the target mass is observed. The dependence of the fragment multiplicity on the projectile mass follows a linear scaling law. The reasons for and the limits of the observed universality of spectator fragmentation are explored within the realm of the available data and with model studies. It is found that the universal properties should persist up to much higher bombarding energies than explored in this work and that they are consistent with universal features exhibited by the intranuclear cascade and statistical multifragmentation models. PACS numbers: 25.70.Mn, 25.70.Pq, 25.75.-q

  8. Importance of the donor:fullerene intermolecular arrangement for high-efficiency organic photovoltaics.

    PubMed

    Graham, Kenneth R; Cabanetos, Clement; Jahnke, Justin P; Idso, Matthew N; El Labban, Abdulrahman; Ngongang Ndjawa, Guy O; Heumueller, Thomas; Vandewal, Koen; Salleo, Alberto; Chmelka, Bradley F; Amassian, Aram; Beaujuge, Pierre M; McGehee, Michael D

    2014-07-01

    The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b']dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) (13)C{(1)H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems. PMID:24932575

  9. Preparation, characterization and photocatalytic behavior of WO3-fullerene/TiO2 catalysts under visible light

    PubMed Central

    2011-01-01

    WO3-treated fullerene/TiO2 composites (WO3-fullerene/TiO2) were prepared using a sol-gel method. The composite obtained was characterized by BET surface area measurements, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, and UV-vis analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. Excellent photocatalytic degradation of a MO solution was observed using the WO3-fullerene, fullerene-TiO2, and WO3-fullerene/TiO2 composites under visible light. An increase in photocatalytic activity was observed, and WO3-fullerene/TiO2 has the best photocatalytic activity; it may attribute to the increase of the photo-absorption effect by the fullerene and the cooperative effect of the WO3. PMID:21774800

  10. Effect of nitrogen atomic percentage on N+-bombarded MWCNTs in cytocompatibility and hemocompatibility.

    PubMed

    Zhao, Mengli; Cao, Ye; Liu, Xiaoqi; Deng, Jianhua; Li, Dejun; Gu, Hanqing

    2014-01-01

    N+-bombarded multi-walled carbon nanotubes (N+-bombarded MWCNTs), with different nitrogen atomic percentages, were achieved by different N ion beam currents using ion beam-assisted deposition (IBAD) on MWCNTs synthesized by chemical vapor deposition (CVD). Characterizations of N+-bombarded MWCNTs were evaluated by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and contact angle. For comparison, the in vitro cytocompatibility of the N+-bombarded MWCNTs with different N atomic percentages was assessed by cellular adhesion investigation using human endothelial cells (EAHY926) and mouse fibroblast cells (L929), respectively. The results showed that the presence of nitrogen in MWCNTs accelerated cell growth and proliferation of cell culture. The higher nitrogen content of N+-bombarded MWCNTs, the better cytocompatibility. In addition, N+-bombarded MWCNTs with higher N atomic percentage displayed lower platelet adhesion rate. No hemolysis can be observed on the surfaces. These results proved that higher N atomic percentage led N+-bombarded MWCNTs to better hemocompatibility. PMID:24666845

  11. Effect of nitrogen atomic percentage on N+-bombarded MWCNTs in cytocompatibility and hemocompatibility

    NASA Astrophysics Data System (ADS)

    Zhao, Mengli; Cao, Ye; Liu, Xiaoqi; Deng, Jianhua; Li, Dejun; Gu, Hanqing

    2014-03-01

    N+-bombarded multi-walled carbon nanotubes (N+-bombarded MWCNTs), with different nitrogen atomic percentages, were achieved by different N ion beam currents using ion beam-assisted deposition (IBAD) on MWCNTs synthesized by chemical vapor deposition (CVD). Characterizations of N+-bombarded MWCNTs were evaluated by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and contact angle. For comparison, the in vitro cytocompatibility of the N+-bombarded MWCNTs with different N atomic percentages was assessed by cellular adhesion investigation using human endothelial cells (EAHY926) and mouse fibroblast cells (L929), respectively. The results showed that the presence of nitrogen in MWCNTs accelerated cell growth and proliferation of cell culture. The higher nitrogen content of N+-bombarded MWCNTs, the better cytocompatibility. In addition, N+-bombarded MWCNTs with higher N atomic percentage displayed lower platelet adhesion rate. No hemolysis can be observed on the surfaces. These results proved that higher N atomic percentage led N+-bombarded MWCNTs to better hemocompatibility.

  12. Effect of nitrogen atomic percentage on N+-bombarded MWCNTs in cytocompatibility and hemocompatibility

    PubMed Central

    2014-01-01

    N+-bombarded multi-walled carbon nanotubes (N+-bombarded MWCNTs), with different nitrogen atomic percentages, were achieved by different N ion beam currents using ion beam-assisted deposition (IBAD) on MWCNTs synthesized by chemical vapor deposition (CVD). Characterizations of N+-bombarded MWCNTs were evaluated by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and contact angle. For comparison, the in vitro cytocompatibility of the N+-bombarded MWCNTs with different N atomic percentages was assessed by cellular adhesion investigation using human endothelial cells (EAHY926) and mouse fibroblast cells (L929), respectively. The results showed that the presence of nitrogen in MWCNTs accelerated cell growth and proliferation of cell culture. The higher nitrogen content of N+-bombarded MWCNTs, the better cytocompatibility. In addition, N+-bombarded MWCNTs with higher N atomic percentage displayed lower platelet adhesion rate. No hemolysis can be observed on the surfaces. These results proved that higher N atomic percentage led N+-bombarded MWCNTs to better hemocompatibility. PMID:24666845

  13. Microanalysis of Ar and He bombarded biomedical polymer films

    Microsoft Academic Search

    M. Manso Silvan; R. Gago; A. Valsesia; J. M. Martínez Duart; F. Rossi

    2007-01-01

    Implantations onto polyethyleneglycol, polycaprolactone and polymethylmethacrylate, carried out with Ar and He ions at 25 and 100KeV with fluences of 5×1013cm?2, have been made with identical ion currents (20?A) but different sweep areas in order to take into account the effect of the ion flux on the composition and structure of these biopolymers. Vibrational (Fourier transformed infrared spectroscopy), microanalytical (Rutherford

  14. Hydrogen peroxide production via electron bombardment on Europa: Laboratory studies

    NASA Astrophysics Data System (ADS)

    Hand, K. P.; Carlson, R. W.

    2005-12-01

    Chemistry on the icy surface of Europa is heavily influenced by the 7.9e10 keV cm-2 s-1 incident particle flux resulting from the Jovian magnetic field. The majority (> 75%) of this energy is in the form of high energy (< 10 MeV) electrons. We have constructed a 1e-8 torr vacuum chamber equipped with a 100 keV electron gun and He-compressor cryostat in order to simulate the electron irradiation environment of Europa. Pure water films of approximately two micron thickness were grown at 100K and then either cooled (to 80K), warmed (to 120K) or left at 100K and subsequently irradiated with 10 keV electrons. Beam current was adjusted to fall between 0.1-5 microAmp based on the desired energy deposition rate. The production of hydrogen peroxide (H2O2) was monitored by observation of the 2850 cm-1 (3.5 micron) band. Production levels were found to lie within the range of 0.1% to 0.3% hydrogen peroxide by number relative to water. This is comparable to surface abundance measurements for peroxide on the surface of Europa (0.13%). This research is supported by the NASA Exobiology program and by the NASA Graduate Student Fellowship Program.

  15. Changes in a surface of polycrystalline aluminum upon bombardment with argon ions

    NASA Astrophysics Data System (ADS)

    Ashkhotov, O. G.; Ashkhotova, I. B.; Bliev, A. P.; Magkoev, T. T.; Krymshokalova, D. A.

    2014-10-01

    The interaction between argon ions and a natural oxide layer of polycrystalline aluminum is studied via Auger electron (AE) and electron energy loss (EEL) spectroscopy. It is found that bombardment with argon ions whose energy is lower than the Al2O3 sputtering threshold results in the accumulation of bombarding ions in interstitial surface voids, thus forming a supersaturated solid solution of target atoms and bombarding ions of argon and nitrogen entrapped by the ion beam from the residual gas of the working chamber of the spectrometer.

  16. Beyond fullerenes: design of nonfullerene acceptors for efficient organic photovoltaics.

    PubMed

    Li, Haiyan; Earmme, Taeshik; Ren, Guoqiang; Saeki, Akinori; Yoshikawa, Saya; Murari, Nishit M; Subramaniyan, Selvam; Crane, Matthew J; Seki, Shu; Jenekhe, Samson A

    2014-10-15

    New electron-acceptor materials are long sought to overcome the small photovoltage, high-cost, poor photochemical stability, and other limitations of fullerene-based organic photovoltaics. However, all known nonfullerene acceptors have so far shown inferior photovoltaic properties compared to fullerene benchmark [6,6]-phenyl-C60-butyric acid methyl ester (PC60BM), and there are as yet no established design principles for realizing improved materials. Herein we report a design strategy that has produced a novel multichromophoric, large size, nonplanar three-dimensional (3D) organic molecule, DBFI-T, whose ?-conjugated framework occupies space comparable to an aggregate of 9 [C60]-fullerene molecules. Comparative studies of DBFI-T with its planar monomeric analogue (BFI-P2) and PC60BM in bulk heterojunction (BHJ) solar cells, by using a common thiazolothiazole-dithienosilole copolymer donor (PSEHTT), showed that DBFI-T has superior charge photogeneration and photovoltaic properties; PSEHTT:DBFI-T solar cells combined a high short-circuit current (10.14 mA/cm(2)) with a high open-circuit voltage (0.86 V) to give a power conversion efficiency of 5.0%. The external quantum efficiency spectrum of PSEHTT:DBFI-T devices had peaks of 60-65% in the 380-620 nm range, demonstrating that both hole transfer from photoexcited DBFI-T to PSEHTT and electron transfer from photoexcited PSEHTT to DBFI-T contribute substantially to charge photogeneration. The superior charge photogeneration and electron-accepting properties of DBFI-T were further confirmed by independent Xenon-flash time-resolved microwave conductivity measurements, which correctly predict the relative magnitudes of the conversion efficiencies of the BHJ solar cells: PSEHTT:DBFI-T > PSEHTT:PC60BM > PSEHTT:BFI-P2. The results demonstrate that the large size, multichromophoric, nonplanar 3D molecular design is a promising approach to more efficient organic photovoltaic materials. PMID:25265412

  17. Extraction and purification of fullerenes: A comprehensive review

    SciTech Connect

    Theobald, J.; Perrut, M. [Separex Chimie Fine, Champigneulles (France); Weber, J.V. [Universite De Metz (France)] [and others

    1995-08-01

    This review summarizes the advances of the last four years in the field of fullerenes purification. Purification involves extraction from soots, which may be considered as a prepurification step, and separation by liquid chromatography, where the different stationary phases tested are listed. The authors also describe other purification techniques, like elution on molecular sieves or activated charcoal, gel permeation, and supercritical fluids purification. The authors purpose is to show the reader the general trends for obtaining pure C{sub 60} and C{sub 70}.

  18. Possible Mechanisms of Fullerene C60 Antioxidant Action

    PubMed Central

    Chistyakov, V. A.; Smirnova, Yu. O.; Prazdnova, E. V.; Soldatov, A. V.

    2013-01-01

    Novel mechanism of antioxidant activity of buckminsterfullerene C60 based on protons absorbing and mild uncoupling of mitochondrial respiration and phosphorylation was postulated. In the present study we confirm this hypothesis using computer modeling based on Density Functional Theory. Fullerene's geroprotective activity is sufficiently higher than those of the most powerful reactive oxygen species scavengers. We propose here that C60 has an ability to acquire positive charge by absorbing inside several protons and this complex could penetrate into mitochondria. Such a process allows for mild uncoupling of respiration and phosphorylation. This, in turn, leads to the decrease in ROS production. PMID:24222918

  19. Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling

    SciTech Connect

    Hoeink, V.; Schmalhorst, J.; Reiss, G. [Thin Films and Nanostructures, Department of Physics, Bielefeld University, P.O. Box 100131, 33501 Bielefeld (Germany); Weis, T.; Lengemann, D.; Engel, D.; Ehresmann, A. [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Kassel University, Heinrich-Plett-Strasse 40, D-34132 Kassel (Germany)

    2008-06-15

    Artificial ferrimagnets have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment (IB) induced patterning of the exchange bias coupling of a single layer reference electrode in magnetic tunnel junctions with He ions is possible. For applications as, e.g., special types of magnetic logic, a combination of the IB induced patterning of the exchange bias coupling and the implementation of an artificial ferrimagnet as reference electrode is desirable. Here, investigations for a pinned artificial ferrimagnet with a Ru interlayer, which is frequently used in magnetic tunnel junctions, are presented. It is shown that in this kind of samples the exchange bias can be increased or rotated by IB induced magnetic patterning with 10 keV He ions without a destruction of the antiferromagnetic interlayer exchange coupling. An IrMn/Py/Co/Cu/Co stack turned out to be more sensitive to the influence of IB than the Ru based artificial ferrimagnet.

  20. Study of boron neutron capture therapy used neutron source with protons bombarding a thick 9Be target.

    PubMed

    Yue, G; Chen, J; Song, R

    1997-06-01

    Neutron sources created by 4-, 3.5-, and 3-MeV protons striking a thick beryllium target were studied via the time-of-flight technique. Protons were accelerated by the Peking University 4.5 MV electrostatic accelerator. Two disk-shaped 9Be targets with thickness 1.5 and 3 mm were used in the measurements. The time-of-flight spectra were observed at zero degrees with respect to the incident proton beam. The analysis to these time-of-flight spectra is given. The time-of-flight spectra were converted to the energy spectra and compared to a neutron spectrum of 7Li(p, n)7 Be reaction with incident energy 2.5 MeV, which was also measured in this work. Restricted by the spectrometer itself, the threshold of the measurements is 400 keV. The results show that by using several MeV protons bombarding a thick beryllium target, reactions other than 9Be(p, n)9B produce significant contributions to the neutron yield with energy less than 1 MeV. PMID:9198018

  1. Polyamide 12/ fullerene C60 composites: Investigation on their mechanical and dielectric properties

    NASA Astrophysics Data System (ADS)

    Zuev, Vjacheslav V.

    2014-05-01

    The effect of fullerene C60 on mechanical properties of polymer nanocomposites based on PA12 was investigated. The nanocomposites were prepared by in situ polymerization. The Young's modulus and tensile strength of the polymer nanocomposites are improved by about 20% with loading of 0.02-0.08 wt.% the fullerene C60. Dielectric spectroscopy was used to investigate the influence of nanoparticles on the relaxation processes in polymer matrix. The segmental relaxation processes become faster with the fullerene C60 addition, an effect associated with a decrease of the glass transition temperature. In contrast, the secondary or ? relaxation process of PA12/ fullerene C60 nanocomposites was observed to slow down with addition of fullerene C60. These observations indicate that fullerene C60 as filler has an effect opposite to antiplasticizing that slow down the secondary relaxation (stiffening the material) in the glass state, while at the same time reducing the alpha relaxation time associated with cooperative segmental motions. It behaviour can be connected with inclusion complex formation between PA12 and fullerene C60.

  2. Fullerenes, PAH, Carbon Nanostructures, and Soot in Low Pressure Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Grieco, William J.; Lafleur, Arthur L.; Rainey, Lenore C.; Taghizadeh, Koli; VanderSande, John B.; Howard, Jack B.

    1997-01-01

    The formation of fullerenes C60 and C7O is known to occur in premixed laminar benzene/oxygen/argon flames operated at reduced pressures. High resolution transmission electron microscopy (HRTEM) images of material collected from these flames has identified a variety of multishelled nanotubes and fullerene 'onions' as well as some trigonous structures. These fullerenes and nanostructures resemble the material that results from commercial fullerene production systems using graphite vaporization. As a result, combustion is an interesting method for fullerenes synthesis. If commercial scale operation is to be considered, the use of diffusion flames might be safer and less cumbersome than premixed flames. However, it is not known whether diffusion flames produce the types and yields of fullerenes obtained from premixed benzene/oxygen flames. Therefore, the formation of fullerenes and carbon nanostructures, as well as polycyclic aromatic hydrocarbons (PAH) and soot, in acetylene and benzene diffusion flames is being studied using high performance liquid chromatography (HPLC) and high resolution transmission electron microscopy (HRTEM).

  3. Selective extraction of higher fullerenes using cyclic dimers of zinc porphyrins.

    PubMed

    Shoji, Yoshiaki; Tashiro, Kentaro; Aida, Takuzo

    2004-06-01

    Higher fullerenes (>/=C76) were selectively extracted from a fullerene mixture obtained from a combustion-based industrial production source by cyclic dimers of beta-unsubstituted porphyrin zinc complexes 2C5-2C7 with C5-C7 alkylene spacers as host molecules. Results of single extraction of the fullerene mixture with 2C5-2C7 together with a beta-substituted analogue of 2C6 (1C6) and spectroscopic titration of 2C6 and 1C6 with C60, C70, and C96 indicated that the host selectivity toward higher fullerenes is much dependent on the structure of the porphyrin units and the size of the host cavity. Sequential three-stage extraction of the fullerene mixture with the best-behaved 2C6 resulted in considerable enrichment in very rare fullerenes C102-C110 (<0.1 abs %) up to 82 abs % (C76-C114, 99 abs %) (356 nm) of total fullerenes. PMID:15161282

  4. Enhanced Fullerene Yield in Plasma-Aerosol Reactor at Cryogenic Boundary Temperature

    E-print Network

    Jouravlev, Mikhail

    2011-01-01

    We demonstrate remarkably enhanced yield of C60 fullerenes in an aerosol discharge chamber due to the additional presence of a strong spatial temperature gradient. The role of the temperature gradients in the increased yield of C60 and fullerene-like structures is discussed. The reaction is not fully reversible and carbon soot matter is formed as a secondary product in the form of carbon aerosol particles. The increasing concentration of C60 was easily recognized from the characteristic UV-spectra. The result of this paper will be useful for improvement of fullerene synthesis technology and for application to constructing new types of aerosol-plasma reactors.

  5. Synthesis of fullerene glycoconjugates via a copper-catalyzed Huisgen cycloaddition reaction.

    PubMed

    Isobe, Hiroyuki; Cho, Kaimei; Solin, Niclas; Werz, Daniel B; Seeberger, Peter H; Nakamura, Eiichi

    2007-10-25

    The synthesis of fullerene-carbohydrate conjugates using a copper-catalyzed [3+2] cycloaddition reaction to facilitate the union of an azido-functionalized sugar and a pentaalkynyl[60]fullerene is straightforward. Thus, fullerenes bearing five oligosaccharides such as Gb3-trisaccharide can be readily accessed. Nanometer-scale molecular architectures presenting as many as 15 sugar moieties in C5-symmetry are readily produced. The cycloaddition reaction proceeds quantitatively under mild conditions without the need to protect the sugar hydroxyl groups. PMID:17915889

  6. Ion peening and stress relaxation induced by low-energy atom bombardment of covalent solids

    SciTech Connect

    Koster, Monika; Urbassek, Herbert M.

    2001-06-01

    Using molecular-dynamics simulation, we study the buildup and relaxation of stress induced by low-energy ({le}150 eV) atom bombardment of a target material. The effect is brought out most clearly by using an initially compressed specimen. As target material, we employ Si, based on the Tersoff potential. By varying the bond strength in the potential, we can specifically study its effect on damage production and stress changes. We find that in general, stress is relaxed by the atom bombardment; only for low bombarding energies and strong bonds, atom bombardment increases stress. We rationalize this behavior by considering the role of energized atoms and of recoil-implanted target atoms.

  7. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 5 March 1944 - 18 August 1944 

    E-print Network

    United States Army Air Corps

    1946-01-01

    Historical Association, IRIS No. 44028. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air Force Historical Association, Maxwell...

  8. Binding of fullerenes and nanotubes to MscL

    NASA Astrophysics Data System (ADS)

    Hilder, Tamsyn A.; Ridone, Pietro; Nakayama, Yoshitaka; Martinac, Boris; Chung, Shin-Ho

    2014-07-01

    Multi-drug resistance is becoming an increasing problem in the treatment of bacterial infections and diseases. The mechanosensitive channel of large conductance (MscL) is highly conserved among prokaryotes. Evidence suggests that a pharmacological agent that can affect the gating of, or block the current through, MscL has significant potential as a new class of antimicrobial compound capable of targeting a range of pathogenic bacteria with minimal side-effects to infected patients. Using molecular dynamics we examine the binding of fullerenes and nanotubes to MscL and demonstrate that both are stable within the MscL pore. We predict that fullerenes will attenuate the flow of ions through MscL by reducing the pore volume available to water and ions, but nanotubes will prevent pore closure resulting in a permanently open pore. Moreover, we confirm experimentally that it is possible to attenuate the flow of ions through MscL using a C60-? cyclodextrin complex.

  9. Fullerene nanowires as a versatile platform for organic electronics

    PubMed Central

    Maeyoshi, Yuta; Saeki, Akinori; Suwa, Shotaro; Omichi, Masaaki; Marui, Hiromi; Asano, Atsushi; Tsukuda, Satoshi; Sugimoto, Masaki; Kishimura, Akihiro; Kataoka, Kazunori; Seki, Shu

    2012-01-01

    The development of organic semiconducting nanowires that act as charge carrier transport pathways in flexible and lightweight nanoelectronics is a major scientific challenge. We report on the fabrication of fullerene nanowires that is universally applicable to its derivatives (pristine C60, methanofullerenes of C61 and C71, and indene C60 bis-adduct), realized by the single particle nanofabrication technique (SPNT). Nanowires with radii of 8–11?nm were formed via a chain polymerization reaction induced by a high-energy ion beam. Fabrication of a poly(3-hexylthiophene) (P3HT): [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) bulk heterojunction organic photovoltaic cell including PC61BM nanowires with precisely-controlled length and density demonstrates how application of this methodology can improve the power conversion efficiency of these inverted cells. The proposed technique provides a versatile platform for the fabrication of continuous and uniform n-type fullerene nanowires towards a wide range of organic electronics applications. PMID:22934128

  10. Li-doped fullerene structures: a molecular modelling study

    NASA Astrophysics Data System (ADS)

    Nicolau, Dan V.

    2005-04-01

    Materials with exceptionally high contents of carbon are used in technologies with various degrees of added value, from quasi-amorphous materials for carbon electrodes used in e.g. lithium batteries to highly organized materials comprising e.g. nanotubes and fullerenes. The present study aims to test the feasibility of predicting the properties of carbon based materials using (i) molecular modelling and simulation techniques; (ii) application to fullerene as an idealized model of nano-pores in carbon materials; and (iii) available experimental data regarding the behaviour of carbon materials for lithium batteries as validation data. It has been found that the increase in the H/C atomic ratio has an ambivalent impact on the structural stability of lithium-doped carbon materials, with the ultimate lithium-doped material being the result of the 'tug of war' between the folding of the 'house-of-cards' structure due to increased flexibility of the idealized pore scaffold and the pore expansion due to the doping process coupled with the increase in structural flexibility. With regard to molecular motors, the simulations demonstrate that small numbers of hydrogenated defects may induce large enough structural changes to damage the smoothness of the surface of the nanogears, but the insertion of lithium atoms may stabilize this deleterious effect.

  11. Binding of fullerenes and nanotubes to MscL

    PubMed Central

    Hilder, Tamsyn A.; Ridone, Pietro; Nakayama, Yoshitaka; Martinac, Boris; Chung, Shin-Ho

    2014-01-01

    Multi-drug resistance is becoming an increasing problem in the treatment of bacterial infections and diseases. The mechanosensitive channel of large conductance (MscL) is highly conserved among prokaryotes. Evidence suggests that a pharmacological agent that can affect the gating of, or block the current through, MscL has significant potential as a new class of antimicrobial compound capable of targeting a range of pathogenic bacteria with minimal side-effects to infected patients. Using molecular dynamics we examine the binding of fullerenes and nanotubes to MscL and demonstrate that both are stable within the MscL pore. We predict that fullerenes will attenuate the flow of ions through MscL by reducing the pore volume available to water and ions, but nanotubes will prevent pore closure resulting in a permanently open pore. Moreover, we confirm experimentally that it is possible to attenuate the flow of ions through MscL using a C60-? cyclodextrin complex. PMID:25030051

  12. Back-bombardment compensation in microwave thermionic electron guns

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Jeremy M. D.; Madey, John M. J.

    2014-12-01

    The development of capable, reliable, and cost-effective compact electron beam sources remains a long-standing objective of the efforts to develop the accelerator systems needed for on-site research and industrial applications ranging from electron beam welding to high performance x-ray and gamma ray light sources for element-resolved microanalysis and national security. The need in these applications for simplicity, reliability, and low cost has emphasized solutions compatible with the use of the long established and commercially available pulsed microwave rf sources and L-, S- or X-band linear accelerators. Thermionic microwave electron guns have proven to be one successful approach to the development of the electron sources for these systems providing high macropulse average current beams with picosecond pulse lengths and good emittance out to macropulse lengths of 4-5 microseconds. But longer macropulse lengths are now needed for use in inverse-Compton x-ray sources and other emerging applications. We describe in this paper our approach to extending the usable macropulse current and pulse length of these guns through the use of thermal diffusion to compensate for the increase in cathode surface temperature due to back-bombardment.

  13. A plausible cause of the late heavy bombardment

    NASA Astrophysics Data System (ADS)

    Morbidelli, A.; Petit, J.-M.; Gladman, B.; Chambers, J.

    2001-03-01

    We show that at the end of the main accretional period of the terrestrial planets, a few percent of the initial planetesimal population in the 1-2~A.U zone is left on highly-inclined orbits in the inner solar system. The final depletion of this leftover population would cause an extended bombardment of all of the terrestrial planets, slowly decaying with a time scale of order 60~Ma. Because of the large impact velocities dictated by the high inclinations, these projectiles would produce craters much larger than those formed by asteroids of equal size on typical current Near-Earth asteroid orbits: on the Moon, basins could have been formed by bodies as small as 20~km in diameter, and 10~km craters could be produced by 400~m impactors. To account for the observed lunar crater record, the initial population of highly--inclined leftovers would need to be a few times that presently in the main asteroid belt, at all sizes, in agreement with the simulations of the primordial sculpting of both these populations. If a terminal lunar cataclysm (a spike in the crater record ~3.9 Ga ago) really occurred on the Moon, it was not caused by the highly--inclined leftover population, because of the monotonic decay of the latter.

  14. Comet impacts and chemical evolution on the bombarded earth

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Aggarwal, Hans

    1992-01-01

    Amino acids yields for previously published shock tube experiments are used with minimum Cretaceous-Tertiary (K/T) impactor mass and comet composition to predict AIB amino acid K/T boundary sediment column density. The inferred initial concentration of all amino acids in the K/T sea and in similar primordial seas just after 10 km comet impacts would have been at least 10 exp -7 M. However, sinks for amino acids must also be considered in calculating amino acid concentrations after comet impacts and in assessing the contribution of comets to the origin of life. The changing concentration of cometary amino acids due to ultraviolet light is compared with the equilibrium concentration of amino acids produced in the sea from corona discharge in the atmosphere, deposition in water, and degradation by ultraviolet light. Comets could have been more important than endogenous agents for initial evolution of amino acids. Sites favorable for chemical evolution of amino acids are examined, and it is concluded that chemical evolution could have occurred at or above the surface even during periods of intense bombardment of earth before 3.8 billion years ago.

  15. Experimental Investigation of Neutral Species from Micrometeoroid Bombardment

    NASA Astrophysics Data System (ADS)

    Collette, A.; Sternovsky, Z.; Rocha, J. R.; Munsat, T. L.; Horanyi, M.

    2014-12-01

    Surface-boundary exospheres exist in a balance between source and loss processes. An important area of uncertainty, highlighted by the MESSENGER observations of Mg and Ca at Mercury, and the recently concluded LADEE observations at the Moon, is the role of micrometeoroid bombardment as a source process for liberating surface species. Unlike sputtering or photon stimulated desorption processes, the physics of micrometeoroid impacts are still poorly understood; in particular, no comprehensive model exists to predict partitioning of impact products between ejecta fragments, charged particles, and neutrals. We present initial experiments at the IMPACT dust accelerator facility (University of Colorado Boulder) aimed at directly measuring the fraction of neutral species liberated in micrometeoroid impacts. Simulated micrometeoroids (micron- and submicron-sized iron spheres) are fired at targets containing refractory elements, including fused silica (SiO2), sapphire (Al2O3), and magnesium fluoride (MgF2). Total quantities of specific impact-generated neutral species are measured using a mass spectrometer, as a function of impactor speed and mass, and compared with well-established scaling laws for charged particle production.

  16. Electron emission from surfaces resulting from low energy positron bombardment

    NASA Astrophysics Data System (ADS)

    Mukherjee, S.; Shastry, K.; Weiss, A. H.

    2009-03-01

    Measurements of the energy distribution of electrons resulting from very low energy positron bombardment of a polycrystalline Au and Cu(100) surfaces provide evidence for a single step transition from an unbound scattering state to an image potential bound state. The primary positron energy threshold for secondary electron emission and cutoff in the secondary electron energy spectra are consistent with a process in which an incident positrons make a transition from a scattering state to a surface-image potential bound while transferring all of the energy difference to an outgoing secondary electron. Estimates of the probability of this process as a function of incident positron energy are also presented. Background free Auger spectra of the MVV transition in Cu and the OVV transition in Au were obtained by setting the incident positron beam energy below the secondary electron emission threshold. Auger electron emission resulted from the annihilation of surface state positrons with core electrons. The low energy tail associated with the low energy CVV Auger transitions in Cu and Au were found to have integrated intensity several times larger than Auger peak providing strong evidence for multi-electron Auger processes.

  17. Electron emission from surfaces resulting from low energy positron bombardment

    NASA Astrophysics Data System (ADS)

    Mukherjee, Saurabh

    Measurements of the secondary electron energy spectra resulting from very low energy positron bombardment of a polycrystalline Au and Cu (100) surfaces are presented that provide evidence for a single step transition from an unbound scattering state to an image potential bound state. The primary positron energy threshold for secondary electron emission and energy cutoff of the positron induced secondary electron energy peak are consistent with an Auger like process in which an incident positron make a transition from a scattering state to a surface-image potential bound while transferring all of the energy difference to an outgoing secondary electron. We term this process: the Auger mediated quantum sticking effect (AQSE). The intensities of the positron induced secondary electron peak are used to estimate the probability of this process as a function of incident positron energy. Positron annihilation induced Auger spectra (PAES) of Cu and Au are presented that are free of all primary beam induced secondary electron background. This background was eliminated by setting the positron beam energy below AQSE threshold. The background free PAES spectra obtained include the first measurements of the low energy tail of CVV Auger transitions all the way down to zero kinetic energy. The integrated intensity of this tail is several times larger than Auger peak itself which provides strong evidence for multi-electron Auger processes.

  18. Ion-assisted deposition of optical thin films - Low energy vs high energy bombardment

    Microsoft Academic Search

    J. R. McNeil; A. C. Barron; S. R. Wilson; W. C. Herrmann Jr.

    1984-01-01

    Oxygen ion-assisted deposition of SiO2 and TiO2 has been investigated as a function of ion energy (30-500 eV) and current density (0-300 microamps\\/sq cm) at the optic. It is shown that both low and high energy ion bombardment improve SiO2 film stoichiometry, although slightly greater improvement is realized for the low energy case. For TiO2 films, low energy bombardment improves

  19. Particle-In-Cell/Monte Carlo Simulation of Ion Back Bombardment in Photoinjectors

    SciTech Connect

    Qiang, Ji; Corlett, John; Staples, John

    2009-03-02

    In this paper, we report on studies of ion back bombardment in high average current dc and rf photoinjectors using a particle-in-cell/Monte Carlo method. Using H{sub 2} ion as an example, we observed that the ion density and energy deposition on the photocathode in rf guns are order of magnitude lower than that in a dc gun. A higher rf frequency helps mitigate the ion back bombardment of the cathode in rf guns.

  20. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 20 May 1943 - 5 March 1944

    E-print Network

    United States Army Air Corps

    1946-01-01

    Association, IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air... Association, IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air...

  1. Transgenic Italian ryegrass (Lolium multiflorum) plants from microprojectile bombardment of embryogenic suspension cells

    Microsoft Academic Search

    X. Ye; Z.-Y. Wang; X. Wu; I. Potrykus; G. Spangenberg

    1997-01-01

    Transgenic forage-type Italian ryegrass (Lolium multiflorum Lam.) plants have been obtained by microprojectile bombardment of embryogenic suspension cells using a chimeric hygromycin phosphotransferase (hph) gene construct driven by rice Act1 5' regulatory sequences. Parameters for the bombardment of embryogenic suspension cultures with the particle inflow gun were partially optimized using transient expression assays of a chimeric #-glucuronidase (gusA) gene driven

  2. Ion bombardment and its effects on the optical properties of metals

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1964-01-01

    An experimental program, to evaluate the change in total hemispherical emittance and solar absorptance of engineering metals used on spacecraft and in spacecraft instrumentation systems, is presented. Three materials, titanium alloy, pure aluminum, and electrolytic copper, were used in the experiment. Results show that emittance, absorptance, and alpha/epsilon ratio of the materials were changed by ion bombardment. The time before the change occurs depends upon the material used, the intensity of bombardment, and the environment assumed.

  3. Genetic transformation of Cavendish banana ( Musa spp. AAA group) cv 'Grand Nain' via microprojectile bombardment

    Microsoft Academic Search

    D. K. Becker; B. Dugdale; M. K. Smith; R. M. Harding; J. L. Dale

    2000-01-01

    An effective method has been developed for the stable transformation and regeneration of Cavendish banana (Musa spp. AAA group) cv 'Grand Nain' by microprojectile bombardment. Embryogenic cell suspensions were initiated using immature\\u000a male flowers as the explant. Cells were co-bombarded with the neomycin phosphotransferase (nptII) selectable marker gene under the control of a banana bunchy top virus (BBTV) promoter or

  4. Genetic transformation of Norway spruce (Picea abies (L.) Karst) using somatic embryo explants by microprojectile bombardment

    Microsoft Academic Search

    Dominique Robertson; Arthur K. Weissinger; Rhonda Ackley; Sarah Glover; Ronald R. Sederoff

    1992-01-01

    Stable transformation of Norway spruce tissue has been obtained following bombardment of mature somatic embryos with pRT99gus, a plasmid that contains neo coding for NPTII, and gusA, coding for ß-glucuronidase, both fused to the CaMV 35S promoter. At least 8 lines have been stably transformed (over 15 months in culture) following bombardment and selection on kanamycin. Polymerase chain reaction analyses

  5. Measurement of positional isotope exchange rates in enzyme catalyzed reactions by fast atom bombardment mass spectrometry 

    E-print Network

    Hilscher, Larry Wayne

    1985-01-01

    of the requiremer ts for the degree of MASTEP. QF SCIENCE August 1985 Major Subject: Chemistry MEASUREMENT OF POSITIONAL ISOTOPE EXCHANGE RATES IN ENZYME CATALYZED REACTIONS BY FAST ATOM BOMBARDMENT MASS SPECTROMETRY A Thesis LARRY NAYNE HILSCHER Approved...MEASUREMENT OF POSITIONAL ISOTOPE EXCHANGE RATES IN ENZYME CATALYZED REACTIONS BY FAST ATOM BOMBARDMENT MASS SPECTROMETRY A Thesis by LARRY NAYNE HILSCHER Submitted to the Gradu te College of Texas A&M University in partial fulfil" mert...

  6. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 20 May 1943 - 5 March 1944 

    E-print Network

    United States Army Air Corps

    1946-01-01

    Association, IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air... Association, IRIS No. 44028. Mission Reports, 18 July 1942 ? 10 August 1943. This copy of the missions of the 42 nd Bombardment Squadron was digitized from the microfilm copy (Air Force Historical Association, IRIS No. 44028) obtained from the Air...

  7. Production of transgenic gentian plants by particle bombardment of suspension-culture cells

    Microsoft Academic Search

    K. Hosokawa; R. Matsuki; Y. Oikawa; S. Yamamura

    2000-01-01

    Cell suspension cultures were established from leaf explants of gentian (Gentiana triflora×G. scabra) for the generation of transgenic plants by particle bombardment. The parameters for the bombardment of suspension culture\\u000a cells with a particle gun were examined by monitoring the transient expression of a gene for ?-glucuronidase driven by the\\u000a cauliflower mosaic virus (CaMV) 35S promoter. We found that prior

  8. Stable transformation of barley callus using biolistic® particle bombardment and the phosphinothricin acetyltransferase (bar) gene

    Microsoft Academic Search

    Carol M. Stiff; Andrzej Kilian; Huaping Zhou; David A. Kudrna; Andris Kleinhofs

    1995-01-01

    Suspension culture cells of barley (Hordeum vulgare L. cv. Klages) were collectec on filters and bombarded with gold particles carrying the Basta® resistance (bar) gene, or both bar and the ß-glucuronidase (uidA) genes in a Biolistic® Particle Accelerator. Filters carrying the bombarded tissues were selected on basal medium with increasing concentrations (maximum of 200 mg I-1) of phosphinothricin. Surviving calli

  9. A faux hawk fullerene with PCBM-like properties

    SciTech Connect

    San, Long K.; Bukovsky, Eric V.; Larson, Bryon W.; Whitaker, James B.; Deng, Shihu; Kopidakis, Nikos; Rumbles, Garry; Popov, Alexey A.; Chen, Yu-Sheng; Wang, Xue B.; Boltalina, Olga V.; Strauss, Steven H.

    2015-01-01

    Reaction of C60, C6F5CF2I, and SnH(n-Bu)3 produced, among other unidentified fullerene derivatives, the two new compounds 1,9-C60(CF2C6F5)H (1) and 1,9-C60(cyclo-CF2(2-C6F4)) (2). The highest isolated yield of 1 was 35% based on C60. Depending on the reaction conditions, the relative amounts of 1 and 2 generated in situ were as high as 85% and 71%, respectively, based on HPLC peak integration and summing over all fullerene species present other than unreacted C60. Compound 1 is thermally stable in 1,2-dichlorobenzene (oDCB) at 160 °C but was rapidly converted to 2 upon addition of Sn2(n-Bu)6 at this temperature. In contrast, complete conversion of 1 to 2 occurred within minutes, or hours, at 25 °C in 90/10 (v/v) PhCN/C6D6 by addition of stoichiometric, or sub-stoichiometric, amounts of proton sponge (PS) or cobaltocene (CoCp2). DFT calculations indicate that when 1 is deprotonated, the anion C60(CF2C6F5)? can undergo facile intramolecular SNAr annulation to form 2 with concomitant loss of F?. To our knowledge this is the first observation of a fullerene-cage carbanion acting as an SNAr nucleophile towards an aromatic C–F bond. The gas-phase electron affinity (EA) of 2 was determined to be 2.805(10) eV by low-temperature PES, higher by 0.12(1) eV than the EA of C60 and higher by 0.18(1) eV than the EA of phenyl-C61-butyric acid methyl ester (PCBM). In contrast, the relative E1/2(0/?) values of 2 and C60, ?0.01(1) and 0.00(1) V, respectively, are virtually the same (on this scale, and under the same conditions, the E1/2(0/?) of PCBM is ?0.09 V). Time-resolved microwave conductivity charge-carrier yield × mobility values for organic photovoltaic active-layer-type blends of 2 and poly-3-hexylthiophene (P3HT) were comparable to those for equimolar blends of PCBM and P3HT. The structure of solvent-free crystals of 2 was determined by single-crystal X-ray diffraction. The number of nearest-neighbor fullerene–fullerene interactions with centroid...centroid (?...?) distances of ? 10.34 Å is significantly greater, and the average ?...? distance is shorter, for 2 (10 nearest neighbors; ave. ?...? distance = 10.09 Å) than for solvent-free crystals of PCBM (7 nearest neighbors; ave. ?...? distance = 10.17 Å). Finally, the thermal stability of 2 was found to be far greater than that of PCBM.

  10. Ion and photon emission from keV cluster impacts on surfaces 

    E-print Network

    Yau, Alice Yau-Lic

    1992-01-01

    as SCANIIR (Surface Composition by Analysis of Neutral and Ion Impact Radiation) and Bombardment induced Light Emission (BLE) were developed to study the surface composition of complex solids [9-12]. Many difficulties were encountered in the process... bombardment was caused by the excitation of the spunered atoms as they left the surface. Radiation from electron bombardment originated in gas-phase collisions above the surface. Zivitz and Thomas [18] identified photon emission can be localized...

  11. The 1 keV to 200 keV X-ray Spectrum of NGC 2992 and NGC 3081

    E-print Network

    Volker Beckmann; Neil Gehrels; Jack Tueller

    2007-04-20

    The Seyfert 2 galaxies NGC 2992 and NGC 3081 have been observed by INTEGRAL and Swift. We report about the results and the comparison of the spectrum above 10 keV based on INTEGRAL IBIS/ISGRI, Swift/BAT, and BeppoSAX/PDS. A spectrum can be extracted in the X-ray energy band ranging from 1 keV up to 200 keV. Although NGC 2992 shows a complex spectrum below 10 keV, the hard tail observed by various missions exhibits a slope with photon index = 2, independent on the flux level during the observation. No cut-off is detectable up to the detection limit around 200 keV. In addition, NGC 3081 is detected in the INTEGRAL and Swift observation and also shows an unbroken Gamma = 1.8 spectrum up to 150 keV. These two Seyfert galaxies give further evidence that a high-energy cut-off in the hard X-ray spectra is often located at energies E_C >> 100 keV. In NGC 2992 a constant spectral shape is observed over a hard X-ray luminosity variation by a factor of 11. This might indicate that the physical conditions of the emitting hot plasma are constant, while the amount of plasma varies, due to long-term flaring activity.

  12. Large odd-numbered carbon clusters from fullerene-ozone reactions

    SciTech Connect

    McElvany, S.W.; Callahan, J.H.; Ross, M.M. (Naval Research Lab., Washington, DC (United States)); Lamb, L.D.; Huffman, D.R. (Univ. of Arizona, Tucson (United States))

    1993-06-11

    The odd-numbered carbon clusters C[sub 119], C[sub 129], and C[sub 139] have been observed in the mass spectra of toluene extracts of fullerene soots and of the products of ozone-fullerene reactions. Specifically, ozone-C[sub 60] reactions yield C[sub 119], ozone-C[sub 70] reactions yield C[sub 139], and ozone-(C[sub 60]/C[sub 70]) reactions produce C[sub 119], C[sub 129], and C[sub 139]. These unexpected species correspond to dimers of C[sub 60], C[sub 60]/C[sub 70], and C[sub 70], respectively, less one carbon atom, and are stable gas-phase ions with behavior similar to that of fullerenes. The results suggest a new route to functionalization and derivatization of fullerenes through controlled ozone-catalyzed cage-opening reactions. 11 refs., 3 figs.

  13. Temperature Field Measurement During the Arc-Discharge Fullerene Generation Process

    E-print Network

    Maruyama, Shigeo

    , Toshio Takagi, Yoshio Kaji and Mitsuru Inoue The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113 of fullerene Thermocouples Graphite AnodeGraphite Cathode He Stepping MotorStepping Motor Water Cooled Cylinder

  14. Nano-engineered materials based on fullerenes: synthesis and biomedical applications

    NASA Astrophysics Data System (ADS)

    Fierascu, Radu Claudiu; Dumitriu, Irina; Ion, Rodica Mariana; Neagu, Monica; Constantin, Carolina; Stavaru, Crina

    2010-11-01

    The nanoengineering of various materials for biomedical application has became in the last decade one of the most important research areas, due to the continuous struggle to find new and more efficient instruments for the therapy of cancer and other diseases. Attempts to obtain functionalized derivatives of fullerene seek the synthesis of watersoluble materials, in order to investigate their effects in physiological conditions. International studies on the biological properties of fullerenes and their derivatives, are now targeted towards anti-tumor effects, pharmacology and their involvement in oxidative stress. Their toxicity, demonstrated both in vitro and in vivo is important for characterization and selection of applications. Phototoxicity of some molecules of fullerenes has been identified as future therapeutic tool. The present paper describes the synthesis, characterization and some biomedical applications of some nanomaterials based on fullerenes.

  15. Evaluation of the physi- and chemisorption of hydrogen in alkali (Na, Li) doped fullerenes

    SciTech Connect

    Ward, Patrick [University of Tennessee, Knoxville (UTK); Teprovich, Jospeph A. [Savannah River National Laboratory (SRNL); Compton, Robert [ORNL; Affholter, Kathleen A [ORNL; Schwartz, Viviane [ORNL; Veith, Gabriel M [ORNL; Zidan, Ragiay [Savannah River National Laboratory (SRNL)

    2015-01-01

    Alkali doped fullerenes synthesized by two different solvent assisted mixing techniques are compared for their hydrogen uptake activity. In this study we investigated the interaction of hydrogen with alkali doped fullerenes via physisorption. In addition, we present the first mass spectrometric evidence for the formation of C60H60 via chemisorption. Hydrogen physisorption isotherms up to 1 atm at temperatures ranging from 77-303 K were measured demonstrating an increase in hydrogen uptake versus pure C60 and increased isosteric heats of adsorption for the lithium doped fullerene Li12C60. However, despite these improvements the low amount of physisorbed hydrogen at 1 atm and 77 K in these materials suggests that fullerenes do not possess enough accessible surface area to effectively store hydrogen due to their close packed crystalline nature.

  16. Modeling the self-assembly of functionalized fullerenes on solid surfaces using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Bubnis, Gregory J.

    Since their discovery 25 years ago, carbon fullerenes have been widely studied for their unique physicochemical properties and for applications including organic electronics and photovoltaics. For these applications it is highly desirable for crystalline fullerene thin films to spontaneously self-assemble on surfaces. Accordingly, many studies have functionalized fullerenes with the aim of tailoring their intermolecular interactions and controlling interactions with the solid substrate. The success of these rational design approaches hinges on the subtle interplay of intermolecular forces and molecule-substrate interactions. Molecular modeling is well-suited to studying these interactions by directly simulating self-assembly. In this work, we consider three different fullerene functionalization approaches and for each approach we carry out Monte Carlo simulations of the self-assembly process. In all cases, we use a "coarse-grained" molecular representation that preserves the dominant physical interactions between molecules and maximizes computational efficiency. The first approach we consider is the traditional gold-thiolate SAM (self-assembled monolayer) strategy which tethers molecules to a gold substrate via covalent sulfur-gold bonds. For this we study an asymmetric fullerene thiolate bridged by a phenyl group. Clusters of 40 molecules are simulated on the Au(111) substrate at different temperatures and surface coverage densities. Fullerenes and S atoms are found to compete for Au(111) surface sites, and this competition prevents self-assembly of highly ordered monolayers. Next, we investigate self-assembled monolayers formed by fullerenes with hydrogen-bonding carboxylic acid substituents. We consider five molecules with different dimensions and symmetries. Monte Carlo cooling simulations are used to find the most stable solid structures of clusters adsorbed to Au(111). The results show cases where fullerene-Au(111) attraction, fullerene close-packing, and hydrogen-bonding interactions can cooperate to guide self-assembly or compete to hinder it. Finally, we consider three bis-fullerene molecules, each with a different "bridging group" covalently joining two fullerenes. To effectively study the competing "standing-up" and "lying-down" morphologies, we use Monte Carlo simulations in conjunction with replica exchange and force field biasing methods. For clusters adsorbed to smooth model surfaces, we determine free energy landscapes and demonstrate their utility for rationalizing and predicting self-assembly.

  17. Spectroscopic and thermodynamic study of charge transfer interactions of retinol palmitate with [60]- and [70]fullerenes by absorption spectrometric method

    NASA Astrophysics Data System (ADS)

    Saha, Avijit; Mukherjee, Asok K.

    2005-04-01

    Retinol palmitate ( 1), which is commonly called 'Vitamin A palmitate', has been shown to form charge transfer (CT) complexes with a series of electron acceptors including [60]- and [70]fullerenes, and from the trends in CT transition energies the vertical ionization potential of 1 has been estimated to be 7.73 eV. Stoichiometries of the fullerene complexes have been shown to be 1(Vitamin 1): 1([70]fullerene) and 1(Vitamin 1): 2([60]fullerene). The enthalpies and entropies of formation of these two complexes have been determined by estimating the formation constants spectrophotometrically at five different temperatures. The complexation phenomenon may be utilised to dissolve the fullerenes in the non-toxic Vitamin A oil and the solution may be used for testing the biological activity of the fullerenes in vivo.

  18. Beyond nC60: strategies for identification of transformation products of fullerene oxidation in aquatic and biological samples

    PubMed Central

    Pycke, Benny F. G.; Chao, Tzu-Chiao; Herckes, Pierre; Westerhoff, Paul

    2013-01-01

    Owing to their exceptional properties and versatility, fullerenes are in widespread use for numerous applications. Increased production and use of fullerenes will inevitably result in accelerated environmental release. However, study of the occurrence, fate, and transport of fullerenes in the environment is complicated because a variety of surface modifications can occur as a result of either intentional functionalization or natural processes. To gain a better understanding of the effect and risk of fullerenes on environmental health, it is necessary to acquire reliable data on the parent compounds and their congeners. Whereas currently established quantification methods generally focus on analysis of unmodified fullerenes, we discuss in this review the occurrence and analysis of oxidized fullerene congeners (i.e., their corresponding epoxides and polyhydroxylated derivatives) in the environment and in biological specimens. We present possible strategies for detection and quantification of parent nanomaterials and their various derivatives. PMID:22644149

  19. A novel fullerene lipoic acid derivative: Synthesis and preparation of self-assembled monolayers on gold

    Microsoft Academic Search

    A. S. Viana; S. Leupold; C. Eberle; T. Shokati; F.-P. Montforts; L. M. Abrantes

    2007-01-01

    Synthesis and preparation of self-assembled monolayers of a novel fullerene lipoic acid derivative on gold are reported. The presence of densely packed SAMs was confirmed by ellipsometry and cyclic voltammetry. The electrochemical response of the modified electrode in organic media exhibits the first two redox peaks characteristic of the extended ?-electron system of fullerene. C60 surface coverage (1.4×10?10molcm?2) has been

  20. Gas-phase ion-molecule reactions of doubly charged fullerenes with oxygen

    Microsoft Academic Search

    James J. Stry; James F. Garvey

    1993-01-01

    The gas-phase ion-molecule chemistry of doubly charged fullerene cations (C[sub n][sup 2+] where n = 46, 48, ..., 60 and 70) with neutral oxygen molecules were investigated using a triple quadrupole mass spectrometer. In this paper, we report additions to the fullerene cage structure which result in the formation of C[sub n]O[sup 2+], C[sub n]O[sub 2][sup 2+], and C[sub n]O[sub

  1. Color tunable metal-cavity organic light-emitting diodes with fullerene layer

    Microsoft Academic Search

    Sijin Han; Changjun Huang; Zheng-Hong Lu

    2005-01-01

    Three primary colors, red, green, and blue have been obtained from a single-emission layer organic light-emitting diode (OLED) through optical design using a half-wavelength all-metal-cavity device. Fullerene is used as an electron transport layer to further enhance the electrical performance of the cavity device and the optical tuning of the cavity OLED. This fullerene layer results in a ~2 V

  2. Quantum information processing architecture with endohedral fullerenes in a carbon nanotube

    E-print Network

    Wan Li Yang; Zhen Yu Xu; Hua Wei; Mang Feng; Dieter Suter

    2010-03-06

    A potential quantum information processor is proposed using a fullerene peapod, i.e., an array of the endohedral fullerenes 15N@C60 or 31P@C60 contained in a single walled carbon nanotube (SWCNT). The qubits are encoded in the nuclear spins of the doped atoms, while the electronic spins are used for initialization and readout, as well as for two-qubit operations.

  3. Three-dimensional crystalline carbon: Stable polymers of C20 fullerene

    Microsoft Academic Search

    Susumu Okada; Yoshiyuki Miyamoto; Mineo Saito

    2001-01-01

    We report on a first-principles total-energy calculation that provides the energetics and electronic structure of stable polymerized fullerites consisting of the smallest fullerene C20. We find that the C20 fullerene has periodic three-dimensional covalent networks with orthorhombic and tetragonal symmetries. Both are found to be energetically stable and to be elemental semiconductors with a moderate energy gap of about 1.5

  4. A new application area for fullerenes: voltage stabilizers for power cable insulation.

    PubMed

    Jarvid, Markus; Johansson, Anette; Kroon, Renee; Bjuggren, Jonas M; Wutzel, Harald; Englund, Villgot; Gubanski, Stanislaw; Andersson, Mats R; Müller, Christian

    2015-02-01

    Fullerenes are shown to be efficient voltage-stabilizers for polyethylene, i.e., additives that increase the dielectric strength of the insulation material. Such compounds are highly sought-after because their use in power-cable insulation may considerably enhance the transmission efficiency of tomorrow's power grids. On a molal basis, fullerenes are the most efficient voltage stabilizers reported to date. PMID:25504254

  5. Optical limiting and excited-state absorption in fullerene solutions and doped glasses

    Microsoft Academic Search

    Duncan W. McBranch; Laura B. Smilowitz; V. Klimov; A. Koskelo; Jeanne M. Robinson; Ben R. Mattes; J. C. Hummelen; F. Wudl; James C. Withers; Nicholas F. Borrelli

    1995-01-01

    We report the ground-state and excited-state optical absorption spectra in the visible and near infrared for several substituted fullerenes and higher fullerenes in toluene solutions. Based on these measurements, broadband predictions of the optical limiting performance of these molecules can be deduced. These predictions are then tested in the wavelength range from 532 nm to 700 nm in intensity-dependent transmission

  6. Dedicated STEM for 200 to 40 keV operation

    Microsoft Academic Search

    N. Dellby; N. J. Bacon; P. Hrncirik; M. F. Murfitt; G. S. Skone; Z. S. Szilagyi; O. L. Krivanek

    2011-01-01

    A dedicated STEM developed for operation at primary energies from 200 keV to 40 keV and lower is described. It has a new cold field emission gun (CFEG) that gives a normalized brightness of 3 × 108 A\\/(m2 sr V), and excellent short-term and long-term stability. It includes two gun lenses (one electrostatic and one electromagnetic), a fast electrostatic beam

  7. Did Saturn's rings form during the Late Heavy Bombardment ?

    E-print Network

    Sebastien Charnoz; Alessandro Morbidelli; Luke H. Dones; Julien Salmon

    2008-11-02

    The origin of Saturn\\' s massive ring system is still unknown. Two popular scenarios - the tidal splitting of passing comets and the collisional destruction of a satellite - rely on a high cometary flux in the past. In the present paper we attempt to quantify the cometary flux during the Late Heavy Bombardment (LHB) to assess the likelihood of both scenarios. Our analysis relies on the so-called Nice model of the origin of the LHB (Tsiganis et al., 2005; Morbidelli et al., 2005; Gomes et al., 2005) and on the size distribution of the primordial trans-Neptunian planetesimals constrained in Charnoz & Morbidelli (2007). We find that the cometary flux on Saturn during the LHB was so high that both scenarios for the formation of Saturn rings are viable in principle. However, a more detailed study shows that the comet tidal disruption scenario implies that all four giant planets should have comparable ring systems whereas the destroyed satellite scenario would work only for Saturn, and perhaps Jupiter. This is because in Saturn\\'s system, the synchronous orbit is interior to the Roche Limit, which is a necessary condition for maintaining a satellite in the Roche zone up to the time of the LHB. We also discuss the apparent elimination of silicates from the ring parent body implied by the purity of the ice in Saturn \\' s rings. The LHB has also strong implications for the survival of the Saturnian satellites: all satellites smaller than Mimas would have been destroyed during the LHB, whereas Enceladus would have had from 40% to 70% chance of survival depending on the disruption model. In conclusion, these results suggest that the LHB is the sweet moment for the formation of a massive ring system around Saturn.

  8. Did Saturn's rings form during the Late Heavy Bombardment?

    NASA Astrophysics Data System (ADS)

    Charnoz, Sébastien; Morbidelli, Alessandro; Dones, Luke; Salmon, Julien

    2009-02-01

    The origin of Saturn's massive ring system is still unknown. Two popular scenarios—the tidal splitting of passing comets and the collisional destruction of a satellite—rely on a high cometary flux in the past. In the present paper we attempt to quantify the cometary flux during the Late Heavy Bombardment (LHB) to assess the likelihood of both scenarios. Our analysis relies on the so-called "Nice model" of the origin of the LHB [Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F., 2005. Nature 435, 459-461; Morbidelli, A., Levison, H.H., Tsiganis, K., Gomes, R., 2005. Nature 435, 462-465; Gomes, R., Levison, H.F., Tsiganis, K., Morbidelli, A., 2005. Nature 435, 466-469] and on the size distribution of the primordial trans-neptunian planetesimals constrained in [Charnoz, S., Morbidelli, A., 2007. Icarus 188, 468-480]. We find that the cometary flux on Saturn during the LHB was so high that both scenarios for the formation of Saturn rings are viable in principle. However, a more detailed study shows that the comet tidal disruption scenario implies that all four giant planets should have comparable ring systems whereas the destroyed satellite scenario would work only for Saturn, and perhaps Jupiter. This is because in Saturn's system, the synchronous orbit is interior to the Roche Limit, which is a necessary condition for maintaining a satellite in the Roche Zone up to the time of the LHB. We also discuss the apparent elimination of silicates from the ring parent body implied by the purity of the ice in Saturn's rings. The LHB has also strong implications for the survival of the saturnian satellites: all satellites smaller than Mimas would have been destroyed during the LHB, whereas Enceladus would have had from 40% to 70% chance of survival depending on the disruption model. In conclusion, these results suggest that the LHB is the "sweet moment" for the formation of a massive ring system around Saturn.

  9. Energy landscape of fullerene materials: A comparion of boron to boron nitride and carbon

    NASA Astrophysics Data System (ADS)

    de, Sandip

    2012-02-01

    After the discovery of the C60 fullerene some 25 years ago, many more hollow and endohedrally doped structures made out of various elements have been proposed theoretically. However, since no other fullerenes have been synthesized up to date, the question arises whether experimentalists have just not yet found a way to synthesize these theoretically predicted fullerenes, or whether they do not exist at all in nature. Following the theoretical discovery of the B80 fullerene by Szwacki et al, various other fullereneand stuffed fullerene structures were proposed but none of them could be synthesized in the laboratory yet. Using the minima hopping global geometry optimization method on the density functional potential energy surface we show that the energy landscape of boron clusters is glass like. Medium size boron clusters exhibit many structures which are lower in energy than the cages. This is in contrast to carbon and boron nitride systems which can be clearly identified as structure seekers. The differences in the potential energy landscape explain why carbon and boron nitride systems are found in nature whereas pure boron fullerenes have not been found. We thus present a methodology which can make predictions on the feasibility of the synthesis of new nano structures.

  10. Electronic Structure Evolution of Fullerene on CH3NH3PbI3

    NASA Astrophysics Data System (ADS)

    Wang, Chenggong; Wang, Congcong; Liu, Xiaoliang; Bi, Cheng; Shao, Yuchuan; Xiao, Zhengguo; Huang, Jinsong; Gao, Yongli

    2015-03-01

    The thickness dependence of fullerene on CH3NH3PbI3 perovskite film surface has been investigated by using ultraviolet photoemission spectroscopy (UPS), X-ray photoemission spectroscopy (XPS) and inverse photoemission spectroscopy (IPES). The lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) can be observed directly with IPES and UPS. It is observed that the HOMO level in fullerene shifts to lower binding energy. The XPS results show an initial shift of core levels to lower binding energy in the perovskite, which indicates that electrons transfer from the perovskite film to fullerene molecules. We observed that the WF of the perovskite is 5.0 eV and the VBM is 0.6 eV. The band gap of the perovskite is 1.66 eV, which is in accordance with previous reports. We also observed the HOMO level of C60 shifts to lower binding energy, indicating a band bending in the C60 region. The perovskite core levels show a strong initial shift to lower binding energy, indicating electron transfer from the perovskite film to fullerene molecules. The strongest electron transfer happened at 1/4 monolayer of fullerene, and further deposition reduced the transfer as forms fullerene forms C60 solid film. NSF CBET-1437656.

  11. Dual growth modes in ion bombarded Si surfaces

    SciTech Connect

    Dhillon, Prabhjeet Kaur; Sarkar, Subhendu [Department of Physics, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab - 140 001 (India)

    2012-06-05

    Morphological studies were done on Si (001) surfaces after rastering them with a 1 keV O{sub 2}{sup +} ion beam at an angle. The resulting mounded morphology was studied using atomic force microscopy (AFM) measurements. The roughness at different length scales were further extracted and quantified from AFM measurements using scaling analysis. Results indicate two growth regimes of the evolving surface which were evident from the power spectral density (PSD) and interface width analysis of the eroded surfaces. Initially the growth is unstable followed by a stable regime of the nanostructures evolved after about 35 minutes of erosion. Temporal studies done on these surfaces show the onset of shadowing at higher sputtering times thus indicating the breakdown of the growth model at these times.

  12. Formation of conductive layers on dielectric substrates by ion bombardment

    NASA Astrophysics Data System (ADS)

    Pichugin, V. F.; Frangulian, T. S.; Kryuchkov, Yu. Yu.; Feodorov, A. N.; Riabchikov, A. I.

    1993-06-01

    The effect of the insulator-conductor transition in magnesium oxide crystals implanted with Fe + ions at doses ranging from 10 16 to 10 17 ions/cm 2 (ion energy 70 keV) was investigated. It was found that the conductive state of MgO does not change on heating of the irradiated crystals up to 1300 K in vacuum. In contrast, heat treatment in air results in a decreasing value of the conductivity. The nature of point defects and their role in annealing processes are discussed on the basis of the optical absorption data. Supplementary data were obtained using the techniques of Rutherford backscattering and channeling of ?-particles. It was shown that changes of stoichiometric composition of the ion-implanted layers play an important role in the insulator-conductor transition.

  13. Electron impact ionization cross sections for C60 fullerene

    NASA Astrophysics Data System (ADS)

    Pal, Satyendra; Anshu; Singh, C.

    2011-06-01

    We have extended and generalized the modified Jain-Khare (JK) semiempirical formalism to the evaluation of partial differential and partial integral ionization cross sections for fullerenes. The differential cross sections corresponding to the production of singly, doubly and triply charged cations in the electron impact ionization of C60 were evaluated at incident electron energies of 100 and 200 eV. The partial integral ionization cross sections calculated in the energy range varying from ionization thresholds to 1000 eV revealed satisfactory agreement with the available experimental and theoretical data. The ionization rate coefficients corresponding to the various cations have also been evaluated using the presently calculated ionization cross sections and Maxwell-Boltzmann energy distributions.

  14. Tunable Porosities and Shapes of Fullerene-Like Spheres

    PubMed Central

    Dielmann, Fabian; Fleischmann, Matthias; Heindl, Claudia; Peresypkina, Eugenia V; Virovets, Alexander V; Gschwind, Ruth M; Scheer, Manfred

    2015-01-01

    The formation of reversible switchable nanostructures monitored by solution and solid-state methods is still a challenge in supramolecular chemistry. By a comprehensive solid state and solution study we demonstrate the potential of the fivefold symmetrical building block of pentaphosphaferrocene in combination with CuI halides to switch between spheres of different porosity and shape. With increasing amount of CuX, the structures of the formed supramolecules change from incomplete to complete spherically shaped fullerene-like assemblies possessing an Ih-C80 topology at one side and to a tetrahedral-structured aggregate at the other. In the solid state, the formed nano-sized aggregates reach an outer diameter of 3.14 and 3.56?nm, respectively. This feature is used to reversibly encapsulate and release guest molecules in solution. PMID:25759976

  15. Geometric and electronic structures of polymerized C32 fullerenes: Electronic structure tuning by fullerene and carbon nanotube filling

    NASA Astrophysics Data System (ADS)

    Maruyama, Mina; Okada, Susumu

    2015-06-01

    We report first-principles total-energy calculations providing the geometric and electronic structures of polymerized small fullerene C32, and C36- and carbon nanotube (CNT)-filled C32 polymers. We found that the pristine C32 polymer is a semiconductor with a direct bandgap of 1.5 eV, while the filled C32 polymers are metals with the carriers distributed on sp2 carbon atoms in the C32 cage. We also found that the C32 polymer possesses a pair of linear dispersion bands in their valence band because of the ? network topology, which is regarded as a graphene-like topology with an internal degree of freedom.

  16. Classical-trajectory Monte Carlo calculations of the electronic stopping cross section for keV protons and antiprotons impinging on hydrogen atoms

    SciTech Connect

    Custidiano, Ernesto R.; Jakas, Mario M. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, 38205 La Laguna, Tenerife (Spain)

    2005-08-15

    Using the classical-trajectory Monte Carlo (CTMC) method, the electronic stopping cross sections of hydrogen atoms by protons and antiprotons impact are calculated. The results show that the CTMC method compares fairly well with previous quantum mechanics calculations of the stopping cross sections for the same colliding pairs. It turns out therefore that the CTMC method constitutes a reliable and, computationally speaking, convenient alternative to calculate the stopping of ions in matter. The present results also show that the stopping appears to be particularly sensitive to the angular momentum (L) of the electron orbit. In the case of protons, the highest sensitivity to L becomes evident around the energy of the maximum stopping. While for antiprotons the largest sensitivity of the stopping to L is observed down at low bombarding energies, i.e., below 10 keV.

  17. Fullerene-enhanced accumulation of p,p'-DDE in agricultural crop species.

    PubMed

    De La Torre-Roche, Roberto; Hawthorne, Joseph; Deng, Yingqing; Xing, Baoshan; Cai, Wenjun; Newman, Lee A; Wang, Chen; Ma, Xingmao; White, Jason C

    2012-09-01

    The effect of C(60) fullerene exposure on the accumulation of dichlorodiphenyldichloroethylene (p,p'-DDE; DDT metabolite) by Cucurbita pepo L. (zucchini), Glycine max L. (soybean), and Solanum lycopersicum L. (tomato) was determined. The plants were grown in 125 mL jars of vermiculite amended with 0 or 40 mg of C(60) fullerenes. Prior to planting, the jars were amended with 40 mL solution containing 100 ng/mL of p,p'-DDE with 0 or 100 mg/L humic acid. During three weeks of growth, plants were watered with the same p,p'-DDE containing solutions. Total shoot p,p'-DDE levels in nonfullerene exposed tomato, soybean, and zucchini were 26.9, 131, and 675 ng, respectively; total root DDE content for the three plants was 402, 5970, and 5830 ng, respectively. Fullerenes increased the shoot p,p'-DDE content of zucchini by 29%; contaminant levels in soybean shoots were decreased by 48% but tomato shoot content was unaffected. The root and total plant p,p'-DDE content of all three species was significantly increased by fullerene exposure; enhanced contaminant uptake ranged from 30 to 65%. Humic acid, regardless of fullerene presence or plant type, significantly decreased the p,p'-DDE uptake. Fullerenes were detected in the roots of all plants but were not detected in plant shoots in the initial study. In a follow up study with zucchini designed to maximize biomass for extraction, over half the analyzed stems contained fullerenes at 60.5 to 4490 ng/g. These findings show that the carbon-based nanomaterials may significantly alter the accumulation and potentially the toxicity of cocontaminants in agricultural systems. PMID:22856886

  18. Localized depth distribution in the bombarded surface of Ag?Cu alloy

    NASA Astrophysics Data System (ADS)

    Wang, Wenmin; Wang, Zhenxia; Lu, Rongrong; Zhu, Fuying; Wu, Xiankang; Guo, Yingmei; Zhu, Jieqing

    1995-09-01

    Combined with electron microbeam techniques such as scanning electron microscopy and electron-induced X-ray emission, a helium microbeam is used to study the effect of Ar + ion bombardment on the surface of a binary alloy Ag 37Cu 63 by particle-induced X-ray emission and Rutherford backscattering. A pronounced change of the surface concentration and depth profile has been found at both Cu-enriched solid solution micro-region and Ag-enriched eutectic mixture micro-region on the alloy surface due to ion bombardment. The preferential sputtering of Ag and bombardment-induced surface segregation is suggested to be attributed to the composition change in the near-surface regions. A superposition of depth distributions determined from different micro-phase-regions is experimentally confirmed.

  19. Evolution of isolated copper clusters under low-energy argon ion bombardment

    NASA Astrophysics Data System (ADS)

    Shyrokorad, D. V.; Kornich, G. V.

    2014-12-01

    The molecular dynamics simulation of the evolution of clusters of copper in a vacuum under low-energy argon ion bombardment has been performed. The clusters consisting of 26, 78, and 390 atoms have been studied at a bombarding particle energy ranging from 1 to 800 eV. The potential of the interaction between copper atoms has been simulated using the embedded atom method, whereas the interaction of copper atoms with argon atoms has been described using the Ziegler-Biersack-Littmark potential. As a result of the simulation, time dependences of the temperature and potential energy and the numerical values of the sputtering coefficients of free clusters under the ion bombardment have been obtained.

  20. The influence of primary ion bombardment conditions on the secondary ion emission behavior of polymer additives

    NASA Astrophysics Data System (ADS)

    Kersting, R.; Hagenhoff, B.; Pijpers, P.; Verlaek, R.

    2003-01-01

    The secondary ion (SI) emission behavior of pure polymer systems is meanwhile well understood. However, common plastics not only consist of the polymer host material but also contain a variety of additives normally present in low concentrations only. In order to better understand the parameters governing the SI emission of these trace compounds we performed a systematic study on the influence of the analysis parameters (primary ion (PI) type, PI energy, electron bombardment for charge compensation, etc.) using model systems. Samples were prepared by spin coating (sub)monolayers of Irganox 1010 onto additive-free low density polyethylene (LDPE). The SI parameters yield, disappearance cross-section and efficiency (yield per damaged area) were determined for PI bombardment with Ga +, Cs +, and SF 5+. Furthermore the damaging influence of electron bombardment for charge compensation on the organic surface layers was investigated.

  1. 40 CFR 721.10271 - 3?H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3?-butanoic acid, 3?-phenyl-, methyl ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...fullerene-C60-Ih-3â²-butanoic acid, 3â²-phenyl-, methyl ester. 721.10271 Section...fullerene-C60-Ih-3?-butanoic acid, 3?-phenyl-, methyl ester. (a) Chemical...fullerene-C60-Ih-3?-butanoic acid, 3?-phenyl-, methyl ester,...

  2. 40 CFR 721.10271 - 3?H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3?-butanoic acid, 3?-phenyl-, methyl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...fullerene-C60-Ih-3â²-butanoic acid, 3â²-phenyl-, methyl ester. 721.10271 Section...fullerene-C60-Ih-3?-butanoic acid, 3?-phenyl-, methyl ester. (a) Chemical...fullerene-C60-Ih-3?-butanoic acid, 3?-phenyl-, methyl ester,...

  3. Effects of low-fluence swift iodine ion bombardment on the crystallization of ion-beam-synthesized silicon carbide

    SciTech Connect

    Intarasiri, S.; Yu, L. D.; Singkarat, S.; Hallen, A.; Lu, J.; Ottosson, M.; Jensen, J.; Possnert, G. [FNRF, Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Department of Microelectronics and Information Technology, Royal Institute of Technology, Electrum 229, S-164 40 Kista-Stockholm (Sweden); Department of Engineering Sciences, Uppsala University, SE-75 121 Uppsala (Sweden); Department of Materials Chemistry, Uppsala University, SE-75 121 Uppsala (Sweden); The Angstroem Laboratory, Division of Ion Physics, Uppsala University, SE-75 121 Uppsala (Sweden)

    2007-04-15

    Ion beam synthesis using high-fluence carbon ion implantation in silicon in combination with subsequent or in situ thermal annealing has been shown to be able to form nanocrystalline cubic SiC (3C-SiC) layers in silicon. In this study, a silicon carbide layer was synthesized by 40-keV {sup 12}C{sup +} implantation of a p-type (100) Si wafer at a fluence of 6.5x10{sup 17} ions/cm{sup 2} at an elevated temperature. The existence of the implanted carbon in Si substrate was investigated by time-of-flight energy elastic recoil detection analysis. The SiC layer was subsequently irradiated by 10-30 MeV {sup 127}I ions to a very low fluence of 10{sup 12} ions/cm{sup 2} at temperatures from 80 to 800 degree sign C to study the effect on the crystallization of the SiC layer. Infrared spectroscopy and Raman scattering measurement were used to monitor the formation of SiC and detailed information about the SiC film properties was obtained by analyzing the peak shape of the Si-C stretching mode absorption. The change in crystallinity of the synthesized layer was probed by glancing incidence x-ray diffraction measurement and transmission electron microscopy was also used to confirm the results and to model the crystallization process. The results from all these measurements showed in a coherent way that the synthesized structure was a polycrystalline layer with nanometer sized SiC crystals buried in a-Si matrix. The crystallinity of the SiC layer was enhanced by the low-fluence swift heavy ion bombardment and also favored by higher energy, higher fluence, and higher substrate temperature. It is suggested that electronic stopping plays a dominant role in the enhancement.

  4. Compact, maintainable 80-KeV neutral beam module

    DOEpatents

    Fink, Joel H. (Livermore, CA); Molvik, Arthur W. (Livermore, CA)

    1980-01-01

    A compact, maintainable 80-keV arc chamber, extractor module for a neutral beam system immersed in a vacuum of <10.sup.-2 Torr, incorporating a nested 60-keV gradient shield located midway between the high voltage ion source and surrounding grounded frame. The shield reduces breakdown or arcing path length without increasing the voltage gradient, tends to keep electric fields normal to conducting surfaces rather than skewed and reduces the peak electric field around irregularities on the 80-keV electrodes. The arc chamber or ion source is mounted separately from the extractor or ion accelerator to reduce misalignment of the accelerator and to permit separate maintenance to be performed on these systems. The separate mounting of the ion source provides for maintaining same without removing the ion accelerator.

  5. Catalytic properties of ion-bombarded non-metals

    NASA Astrophysics Data System (ADS)

    Wolf, G. K.; Zucholl, K.; Folger, H.

    1984-02-01

    Sputtering, ion implantation and ion beam mixing are useful new techniques for producing catalysts consisting of an active metal introduced in a non-active substrate. We studied the performance of implanted and ion beam mixed electrocatalysts containing platinum as the active component in graphite or RuO 2 substrates. The specimens were used as electrodes in electrochemical cells and their activity was studied for the oxidation of formic acid and methanol, the reduction of oxygen and the evolution of hydrogen. All reactions are important for fuel cells and hydrogen production. The intermixing of a thin Pt layer with a RuO 2 substrate by means of 150 keV Kr + beams did not change the activity, normalized to a standard Pt surface concentration, for formic acid oxidation and oxygen reduction. The activity for methanol oxidation, however, decreased with increasing mixing dose and was nearly zero for implanted Pt in RuO 2. For Pt on graphite substrates the activity for all reactions increased with the mixing dose up to 10 16{Kr +}/{cm 2}, and decreased or saturated above this value. The observed dependency of the activity on the individual chemical reaction as well as on the type of substrate was explained provisionally by a cooperation of small particle effects and metal-substrate interactions.

  6. Lifetime of 981-Kev State in Li-8

    E-print Network

    Throop, M. J.; Youngblood, David H.; Morrison, G. C.

    1971-01-01

    Axgonne National Laboratory, Axgonne, Illinois 60439 (Received 17 November 1970) The lifetime of the 981-keV state in Li produced in the D(Li,p)Li * reaction was mea- sured by the two-backing variant of the Doppler-shift attenuation method... of the Li' first excited state at 981 keV by means of the attenuated-Doppler-shift technique and a comparison of the result with pre- dictions of a shell-model calculation for the 1p shell. ' An upper limit of 35 fsec for this lifetime has been...

  7. The Smallest Stable Fullerene, M@C28 (M = Ti, Zr, U) Gregory S. Boebinger, National High Magnetic Field Laboratory

    E-print Network

    Weston, Ken

    The Smallest Stable Fullerene, M@C28 (M = Ti, Zr, U) Gregory S. Boebinger, National High Magnetic resulting from laser vaporization of a titanium-containing graphite target. Ti@C28 forms as the smallest fullerene. Note the close, but clear, separation between Ti@C28 and the smallest empty cage (C32), differing

  8. Electrochemistry of (Dihapto-Buckminster-Fullerene) Pentacarbonyl Tungsten(0): An Experiment for the Inorganic Chemistry Laboratory, Part III

    ERIC Educational Resources Information Center

    Igartua-Nieves, Elvin; Ocasio-Delgado, Yessenia; Rivera-Pagan, Jose; Cortes-Figueroa, Jose E.

    2007-01-01

    Cyclic voltammetry experiments on [60]fullerene, (C[subscript 60]), and (dihapto-[60]fullerene) pentacarbonyl tungsten(0), ([eta][superscript 2]-C[subscript 60])W(CO)[subscript 5], constitute an educational experiment for the inorganic chemistry laboratory with a primary objective to teach the chemical interpretation of a voltammogram, in…

  9. Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases

    E-print Network

    McGehee, Michael

    to bandgap widening associated primarily with changes in polymer conjugation length. We also observe an energetic offset of up to 350 meV associated with polymer:fullerene intermolecular interactions. The firstCharacterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions

  10. DNA-assisted photoinduced charge transfer between a cationic poly(phenylene vinylene) and a cationic fullerene.

    PubMed

    Park, Youngil; Liu, Zhongwei; Routh, Prahlad K; Kuo, Cheng-Yu; Park, Young-Shin; Tsai, Hsinhan; Martinez, Jennifer S; Shreve, Andrew P; Cotlet, Mircea; Wang, Hsing-Lin

    2015-06-28

    Water-soluble cationic conjugated poly(phenylene vinylene) (PPV) and cationic fullerene were complexed with negatively charged single stranded DNA and double stranded DNA via electrostatic interactions to achieve photoinduced charge transfer with efficiencies as high as those observed from oppositely charged, cationic PPV and anionic fullerene but with distinctly different quenching mechanisms. PMID:25894733

  11. The human immunodeficiency virus-reverse transcriptase inhibition activity of novel pyridine/pyridinium-type fullerene derivatives.

    PubMed

    Yasuno, Takumi; Ohe, Tomoyuki; Takahashi, Kyoko; Nakamura, Shigeo; Mashino, Tadahiko

    2015-08-15

    In the present study, we describe the synthesis of a novel set of pyridine/pyridinium-type fullerene derivatives. The products were assessed for human immunodeficiency virus-reverse transcriptase inhibition activities. All novel fullerene derivatives showed potent human immunodeficiency virus-reverse transcriptase inhibition without cytotoxicity. PMID:26081290

  12. Transient transformation of pollen and embryogenic tissues of white spruce ( Picea glauca (Moench.) Voss) resulting from microprojectile bombardment

    Microsoft Academic Search

    Ying-hong Li; Francine M. Tremblay; Armand Séguin

    1994-01-01

    Detailed analyses of the physical parameters inherent in the microprojectile bombardment technology necessary to produce optimum transient -glucuronidase (GUS) expression were undertaken in pollen and embryogenic tissues of white spruce. Higher helium pressure used for microprojectile bombardment resulted in lower GUS expression in pollen, but in higher GUS expression in embryogenic tissues. Modification of the osmoticum of the culture medium

  13. A sawtooth-like timeline for the first billion years of lunar bombardment A. Morbidelli a,n

    E-print Network

    Mojzsis, Stephen J.

    that the net number of basins formed on the Moon was $ 45250. From our expected bombardment timeline, we in revised form 26 July 2012 Accepted 27 July 2012 Editor: T.M. Harrison Available online 10 October 2012 South Pole Aitken a b s t r a c t We revisit the early evolution of the Moon's bombardment. Our work

  14. The effect of DNA\\/gold particle preparation technique, and particle bombardment device, on the transformation of barley ( Hordeum vulgare )

    Microsoft Academic Search

    W. A. Harwood; S. M. Ross; P. Cilento; J. W. Snape

    2000-01-01

    Immature embryos of the spring barley variety GoldenPromise, were bombarded with three different particledelivery systems and both transient and stabletransformation examined. In addition, a range oftechniques for the preparation of the DNA coated goldparticles was examined. Fertile transgenic barleyplants were obtained using three particle preparationtechniques which differed in the amount of gold andDNA used for each bombardment. However, only one

  15. Co-Exposure with Fullerene May Strengthen Health Effects of Organic Industrial Chemicals

    PubMed Central

    Róg, Tomasz; Cramariuc, Oana; Vanhala, Esa; Tornaeus, Jarkko; Taberman, Helena; Jänis, Janne; Alenius, Harri; Vattulainen, Ilpo; Laine, Olli

    2014-01-01

    In vitro toxicological studies together with atomistic molecular dynamics simulations show that occupational co-exposure with C60 fullerene may strengthen the health effects of organic industrial chemicals. The chemicals studied are acetophenone, benzaldehyde, benzyl alcohol, m-cresol, and toluene which can be used with fullerene as reagents or solvents in industrial processes. Potential co-exposure scenarios include a fullerene dust and organic chemical vapor, or a fullerene solution aerosolized in workplace air. Unfiltered and filtered mixtures of C60 and organic chemicals represent different co-exposure scenarios in in vitro studies where acute cytotoxicity and immunotoxicity of C60 and organic chemicals are tested together and alone by using human THP-1-derived macrophages. Statistically significant co-effects are observed for an unfiltered mixture of benzaldehyde and C60 that is more cytotoxic than benzaldehyde alone, and for a filtered mixture of m-cresol and C60 that is slightly less cytotoxic than m-cresol. Hydrophobicity of chemicals correlates with co-effects when secretion of pro-inflammatory cytokines IL-1? and TNF-? is considered. Complementary atomistic molecular dynamics simulations reveal that C60 co-aggregates with all chemicals in aqueous environment. Stable aggregates have a fullerene-rich core and a chemical-rich surface layer, and while essentially all C60 molecules aggregate together, a portion of organic molecules remains in water. PMID:25473947

  16. Optical and structural properties of fullerene films doped with cadmium telluride

    NASA Astrophysics Data System (ADS)

    Zakharova, I. B.; Ziminov, V. M.; Romanov, N. M.; Kvyatkovskii, O. E.; Makarova, T. L.

    2014-05-01

    Composite thin-film structures based on C60/CdTe were prepared by discrete vacuum evaporation in a quasi-closed volume and by vacuum evaporation from a Knudsen cell. The synthesized fullerene samples contained cadmium telluride with a content ranging from 1 to 50 wt %. The morphology and composition of the films were controlled using scanning electron microscopy and energy-dispersive X-ray analysis. The optimum geometry, the total energy, and the spectrum of excited states of the fullerene-cadmium telluride molecular complex were calculated by quantum-chemical methods. The spectral dependences of the photo-luminescence, Raman scattering, extinction coefficient, and refractive index were measured for different compositions. It was found that, in contrast to the spectra of pure fullerene, the luminescence and absorption spectra of the fullerene doped with cadmium telluride exhibit an additional peak in the wavelength range of 600-620 nm. These data were interpreted as the existence of dipole-allowed transitions in the spectrum of excited singlet states of the fullerene due to the interaction with cadmium telluride. The composite films had an increased resistance to degradation under the action of oxygen and water vapor.

  17. Formation of a new electric material: Fullerene/metal polycrystalline film

    SciTech Connect

    Xu, Bingshu; Tanaka, Shunichiro

    1997-07-01

    An investigation of the formation behavior and mechanism of onion like fullerene/metal polycrystalline film under electron beam irradiation is presented. Metallic nanoparticles of Al, Au and Pt having diameters of 1{approximately}35 nm, were supported on an amorphous carbon film with thickness of about 20 nm. The amorphous carbon film transformed into onion-like fullerene film under electron beam irradiation, with intensity about 10{sup 20} e/cm{sup 2}{center{underscore}dot}sec using high resolution transmission electron microscopy. The transformation mechanism and growth morphology have been investigated. It is found that the nucleation and growth process of onion-like fullerenes from amorphous carbon were divided into several steps: Firstly, a few elliptic shells of carbon were induced under Al, Au or Pt nanoparticles; secondly, a gradual reorganization took place into the structures composed of quasi-concentric spheroid or sphered graphite, i.e., onion like fullerenes, and finally, fullerenes were bonded to each other into a film.

  18. Skin intervention of fullerene-integrated nanoemulsion in structural and collagen regeneration against skin aging.

    PubMed

    Ngan, Cheng Loong; Basri, Mahiran; Tripathy, Minaketan; Abedi Karjiban, Roghayeh; Abdul-Malek, Emilia

    2015-04-01

    Despite the fact that intrinsic oxidative stress is inevitable, the extrinsic factor such as ultraviolet radiation enhances reactive oxygen species (ROS) generation resulting in premature skin aging. Nanoemulsion was loaded with fullerene, a strong free radical scavenger, and its efficacy to provide protection and regenerative effect against ROS-induced collagen breakdown in human skin was studied. Stable fullerene nanoemulsions were formulated using high shear homogenization and ultrasonic dispersion technique. An open trial was conducted using fullerene nanoemulsion on skin twice a day for 28 days. The mean collagen score significantly increased (P<0.05) from 36.53±4.39 to 48.69±5.46 with 33.29% increment at the end of the treatment. Biophysical characteristics of skin revealed that skin hydration was increased significantly (P<0.05) from 40.91±7.01 to 58.55±6.08 corneometric units (43.12% increment) and the water was able to contain within the stratum corneum without any increased in transepidermal water loss. In the in vitro safety evaluation, fullerene nanoemulsion showed no acute toxicity on 3T3 fibroblast cell line for 48h and no indication of potential dermal irritation. Hence, the fullerene nanoemulsion may assist in protecting collagen from breakdown with cosmeceutical benefit. PMID:25619806

  19. Creation and destruction of C{sub 60} and other fullerene solids. Final report

    SciTech Connect

    Huffman, D.R.

    1996-06-05

    The 1990 announcement of the Huffman-Kratschmer fullerene-production technique set off a world-wide explosion of research into the properties and potential applications of C{sub 60} and C{sub 70}. In the last five years, 4,000+ fullerene articles have appeared in the scientific literature dealing with these fascinating molecules and their condensed phases. They possess a complex chemistry reminiscent of the alkenes, and this has led to the syntheses of numerous new compounds and fullerene-based materials, with suggested applications ranging from medicine to photo-conducting polymers to rocket fuel. The work summarized in this report focused on the creation and destruction of fullerene-based materials, for the purpose of producing new materials of interest. This three year project was supported by a grant from the Advanced Energy Projects Division, Office of Basic Energy Sciences, U.S. Department of Energy (DE-FG03-93ER12133). Following are outlines of the work completed in each of the three years, a section devoted to the professional and educational development of those involved, a brief section on the outlook for fullerene-based materials, and an appendix listing the publications resulting from this project.

  20. Light-induced EPR study of charge transfer in poly(3-hexylthiophene)/fullerene bulk heterojunction

    NASA Astrophysics Data System (ADS)

    Krinichnyi, V. I.; Yudanova, E. I.; Denisov, N. N.

    2009-07-01

    The first results of the light-induced EPR study of magnetic, relaxation, and dynamic parameters of charge carriers background photoinduced by optical photons (1.7-3.4 eV) in poly(3-hexylthiophene)/fullerene bulk heterojunctions are described. All magnetic resonance parameters for positively charged polaron and negatively charged fullerene ion-radical in radical pairs photoinduced in the composite were determined separately by the steady-state microwave saturation method. Paramagnetic susceptibility of charge carriers reflects their activation dynamics and exchange interaction. A decay of long-living radical pairs depends on the spatial distance between photoinduced charge carriers. The one-dimensional polaron diffusion along the polymer chain and fullerene rotation near the main molecular axis was shown to follow activation Elliot hopping model and to be governed by photon energy. The difference in activation energies of the charge carriers' dynamics and in their dependence on the exciting photon energy proves their noninteracting character in the polymer/fullerene composite. Main magnetic, relaxation and dynamics parameters of charge carriers are governed by the photon energy band due to inhomogeneity of distribution of polymer and fullerene domains in the composite.

  1. Light-induced EPR study of charge transfer in poly(3-hexylthiophene)/fullerene bulk heterojunction.

    PubMed

    Krinichnyi, V I; Yudanova, E I; Denisov, N N

    2009-07-28

    The first results of the light-induced EPR study of magnetic, relaxation, and dynamic parameters of charge carriers background photoinduced by optical photons (1.7-3.4 eV) in poly(3-hexylthiophene)/fullerene bulk heterojunctions are described. All magnetic resonance parameters for positively charged polaron and negatively charged fullerene ion-radical in radical pairs photoinduced in the composite were determined separately by the steady-state microwave saturation method. Paramagnetic susceptibility of charge carriers reflects their activation dynamics and exchange interaction. A decay of long-living radical pairs depends on the spatial distance between photoinduced charge carriers. The one-dimensional polaron diffusion along the polymer chain and fullerene rotation near the main molecular axis was shown to follow activation Elliot hopping model and to be governed by photon energy. The difference in activation energies of the charge carriers' dynamics and in their dependence on the exciting photon energy proves their noninteracting character in the polymer/fullerene composite. Main magnetic, relaxation and dynamics parameters of charge carriers are governed by the photon energy band due to inhomogeneity of distribution of polymer and fullerene domains in the composite. PMID:19655902

  2. Light-induced EPR study of charge transfer in poly(3-hexylthiophene)/fullerene bulk heterojunction

    SciTech Connect

    Krinichnyi, V. I.; Yudanova, E. I.; Denisov, N. N. [Institute of Problems of Chemical Physics, RAS, Semenov Avenue 1, Chernogolovka 142432 (Russian Federation)

    2009-07-28

    The first results of the light-induced EPR study of magnetic, relaxation, and dynamic parameters of charge carriers background photoinduced by optical photons (1.7-3.4 eV) in poly(3-hexylthiophene)/fullerene bulk heterojunctions are described. All magnetic resonance parameters for positively charged polaron and negatively charged fullerene ion-radical in radical pairs photoinduced in the composite were determined separately by the steady-state microwave saturation method. Paramagnetic susceptibility of charge carriers reflects their activation dynamics and exchange interaction. A decay of long-living radical pairs depends on the spatial distance between photoinduced charge carriers. The one-dimensional polaron diffusion along the polymer chain and fullerene rotation near the main molecular axis was shown to follow activation Elliot hopping model and to be governed by photon energy. The difference in activation energies of the charge carriers' dynamics and in their dependence on the exciting photon energy proves their noninteracting character in the polymer/fullerene composite. Main magnetic, relaxation and dynamics parameters of charge carriers are governed by the photon energy band due to inhomogeneity of distribution of polymer and fullerene domains in the composite.

  3. Destruction of CO ice and formation of new molecules by irradiation with 28 keV O 6+ ions

    NASA Astrophysics Data System (ADS)

    de Barros, A. L. F.; Seperuelo Duarte, E.; Farenzena, L. S.; da Silveira, E. F.; Domaracka, A.; Rothard, H.; Boduch, P.

    2011-05-01

    The effect of solar wind on cometary ice was studied by using oxygen ions with energy near to that corresponding to their maximum abundance in space for bombarding CO ice. This gas was condensed on a CsI substrate at 14 K and irradiated by 28 keV 18O 6+ ions up to a final fluence of 1.3 × 10 16 cm -2. We have used a methodology in which the sputtering yields, the destruction rate of CO, and the rate of formation of new molecular species are determined by Fourier transform infrared spectroscopy (FTIR). In the current experiment, the condensation of a thin water ice film has prevented the CO sputtering. Quantities such as the dissociation yield, Yd (the number of ice molecules destroyed or dissociated per projectile impact), and the formation yield, Yf (the number of daughter molecules of a given species formed per projectile) are found to be more appropriate and useful than using an integrated or average cross section, since the projectiles are slowing down in the ice from their initial energy until zero velocity (implantation).

  4. Fullerene genesis by ion beams - II: Disclinations and the corranulene road

    NASA Astrophysics Data System (ADS)

    Chadderton, Lewis T.; Gamaly, Eugene G.

    1996-10-01

    A new defect-based model for the growth of the fullerene molecule, C 60, assembling from a hot, homogenous and dense ensemble of carbon atoms, or "primeval soup", is presented. Routes comprising swift open channels to fullerene pass through a succession of carbon clusters which are characterised by "magic" numbers related to high reactivity and maximization of the number of dangling bonds per cluster. There is a critical high temperature nucleation leap into three dimensions at the corranulene kernel C 20. This is determined by the appearance of a pentagon-based defect, the wedge disclination, which is then in turn responsible for the growth of C 60, multiple (or "hedge-hog") disclinations, higher order fullerenes, nested (and seeded) onion-like clusters and, ultimately, tiny crystalline stable polyhedra. Disclinations play a role in the development of three-dimensional aromatic molecules similar to that of screw dislocations in crystal growth.

  5. Fullerene/iron complexes obtained by laser synthesis from gas/aerosol phases

    NASA Astrophysics Data System (ADS)

    Alexandrescu, Rodica; Crunteanu, Aurelian; Morjan, Ion G.; Petcu, Stela; Voicu, Ion N.; Diamandescu, Lucian; Armand, Xavier; Herlin-Boime, Nathalie; Mayne, Martine; Reynaud, Cecile

    2001-06-01

    The preliminary results on the laser synthesis of carbonaceous nanoparticles, which exhibit some characteristic features of fullerene/iron complexes, are reported. The nanopowders were obtained by the laser pyrolysis of a gas phase mixture containing hydrocarbon and alternatively iron pentacarbonyl vapors or ferrocene aerosols. The vapors of iron pentacarbonyl were carried out in the reactor through the intermediate of a bubblier; in the runs using ferrocene, this one was solved in benzene and brought into the reaction zone as aerosol. The reactant mixture contained also nitrous oxide, as oxidizer, and sulphur hexafluoride as energy transfer agent. The as- synthesized powders were toluene extracted and characterized by different analytical methods, such as High Performance Liquid Chromatography (HPLC), IR transmission spectroscopy and Moessbauer spectroscopy. The identification of fullerene-metal complexes was performed by Moessbauer spectroscopy. The Moessbauer transmission spectrum has evidenced the formation of both fullerene phases with iron inside and outside the cage.

  6. Investigation of the Reactions and Distribution of Polycyclic Aromatic Hydrocarbons and Fullerenes in Extraterrestrial Material

    NASA Technical Reports Server (NTRS)

    Zare, Richard N.

    2005-01-01

    The work funded by this research grant includes four specific projects: (1) Mapping the spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in a variety of meteoritic samples and comparing this distribution with mineralogical features of the meteorite to determine whether a correlation exists between the two. (2) Developing a method for detection of fullerenes in extraterrestrial samples using microprobe laser-desorption laser-ionization mass spectrometry ( pL2MS) and utilizing this technique to investigate fullerene presence, while exploring the possibility of spatially mapping the fullerene distribution in these samples through in situ detection. (3) Investigating a possible formation pathway for meteoritic and ancient terrestrial kerogen involving the photochemical reactions of PAHs with alkanes under prebiotic and astrophysically relevant conditions. (4) Studying reaction pathways and identifying the photoproducts generated during the photochemical evolution of PAH-containing interstellar ice analogs as part of an ongoing collaboration with researchers at the Astrochemistry Lab at NASA Ames.

  7. Boosting activation of oxygen molecules on C60 fullerene by boron doping.

    PubMed

    Li, Qiao-Zhi; Zheng, Jia-Jia; Dang, Jing-Shuang; Zhao, Xiang

    2015-02-01

    The activation of oxygen molecules on boron-doped C60 fullerene (C59 B) and the subsequent water formation reaction are systematically investigated by using hybrid density functional calculations. Results indicate that C59 B shows a favorable ability to activate oxygen molecules both kinetically and thermodynamically. The oxygen molecule is first adsorbed on the boron atom, which is identified to be the most reactive site in C59 B for O2 adsorption because of its high positive charge and spin density. The adsorption structure C59 B?O2 can further isomerize to form two products with small reaction barriers. Water formation reactions upon these two structures are energetically favorable and suggest a four-electron mechanism for the oxygen reduction reaction catalyzed by C59 B. This work provides a reliable theoretical insight into the catalytic properties of boron-doped fullerene, which is believed to be helpful to explore fullerene catalysts. PMID:25399745

  8. C 36, a hexavalent building block for fullerene compounds and solids

    NASA Astrophysics Data System (ADS)

    Fowler, P. W.; Heine, T.; Rogers, K. M.; Sandall, J. P. B.; Seifert, G.; Zerbetto, F.

    1999-02-01

    Structures and energies are calculated at the DFTB level for C 36-based fullerenes, hydrides, oligomers and solids. The two fullerenes with minimal pentagon adjacencies are isoenergetic. The isomer implicated in recent experiments has C6 v broken symmetry, a small HOMO-LUMO gap and can gain or lose up to six electrons. C 36 forms stronger inter-cage bonds than larger fullerenes. A favoured ?-bonding pattern rationalises a dimer with ten times the stabilisation of (C 60) 2, a linear polymer, a 'superbenzene' oligomer, a 'supergraphite' layer and a hexagonal close-packed solid with a monomer stabilisation of 522 kJ mol -1 and a d-spacing (6.82 Å) compatible with the experiments.

  9. B 36N 36 fullerene-like nanocages: A novel material for drug delivery

    NASA Astrophysics Data System (ADS)

    Ganji, M. D.; Yazdani, H.; Mirnejad, A.

    2010-07-01

    We study interaction between B 36N 36 fullerene-like nanocage and glycine amino acid from the first- principles. Binding energy is calculated and glycine binding to the pure C 60 fullerene is compared. We also analyze the electronic structure and charge Mulliken population for the energetically most favorable complexes. Our results indicate that glycine can form stable bindings with B 36N 36 nanocage via their carbonyl oxygen (O) active site while, the C 60 fullerene might be unable to form stable bindings to glycine amino acid via their active sites, which is consistence with recent experimental and theoretical investigations. Thus, we arrive at the prediction that the B 36N 36 nanocage can be implemented as a novel material for drug delivery applications.

  10. Solvation of fullerene in a course grained water: A molecular dynamics simulation study

    NASA Astrophysics Data System (ADS)

    Patawane, Sanwardhini; Pant, Shashank; Choudhury, Niharendu

    2015-06-01

    We present a detailed molecular dynamics simulation investigation on hydration of C60 fullerene in a coarse-grained water-like solvent. Based on our recent study (J. Chem. Phys. 2013), which has demonstrated the capability of a coarse-grained, core-soft model of water to describe water-like anomalies, we report here the applicability of this model to describe hydration characteristic of C60 fullerenes. Molecular dynamics simulation has been performed in NVE ensemble and structural characteristics of water around C60 fullerene have been analyzed by calculating C60-water radial distribution function. The computational economy and simplicity of the coarse-grained model will allow us to investigate self-assembly processes that require simulations of a much larger system over a longer period of time.

  11. Ordering of fullerene and carbon nanotube thin films under energetic ion impact

    SciTech Connect

    Kumar, Amit [Institut NEEL, CNRS and Universite Joseph Fourier, 25 rue des Martyrs, BP166, 38042 Grenoble Cedex 9 (France); Avasthi, D. K. [Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, P.O. Box 10502, New Delhi 110067 (India); Pivin, J. C. [Centre Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3-CNRS, Batiment 108, 91405 Orsay Campus (France); Koinkar, P. M. [Center for International Cooperation in Engineering Education (CICEE), University of Tokushima, Tokushima 7708506 (Japan)

    2008-06-02

    We report the ordering of carbon nanostructures under energetic ion irradiation at low fluence (<5x10{sup 11} ions/cm{sup 2}). Fullerene thin films and multiwalled carbon nanotube (MWCNT) films were irradiated with 200 MeV Au and 60 MeV Ni ions at different ion fluences, respectively. The changes in the irradiated films have been investigated by means of Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction, and Raman spectroscopy. FTIR and Raman spectroscopy show the improvement of vibration strength in low fluence irradiated fullerene and MWCNT films. X-ray diffraction analysis on low fluence irradiated fullerene films revealed the structural order along the (220) atomic planes.

  12. Second-order susceptibility in asymmetric quantum wells and its control by proton bombardment

    E-print Network

    Fejer, Martin M.

    of the quantum well structure. We obtain the envelope functions, $,, in the effective mass approximation quantum well and the subband wave functions. The sample, grown on a semi-insulating GaAs substrateSecond-order susceptibility in asymmetric quantum wells and its control by proton bombardment S. J

  13. Concentration microproles in iron silicides induced by low energy ion bombardment

    E-print Network

    Zexian, Cao

    with low energy ions is of great interest in many areas as, e.g., sputter depth pro®ling or ion assisted thin ®lm deposition [1,2]. The surface-near region of a multi-component target will change under ionConcentration micropro®les in iron silicides induced by low energy Ar ion bombardment Zexian Cao

  14. Front-side bombarded metal plated CMOS electron sensors Hod Finkelstein1

    E-print Network

    Ginosar, Ran

    above are eliminated. The EBCCD is incorporated into the vacuum tube with the photocathode. The emitted, integrated over time and processed. The numerous stages of the detection process manifest themselves, amplified by electron-bombarded semiconductor (EBS) gain, on the order of one thousand, depending

  15. Incidence angle distributions of ions bombarding grounded surfaces in high density plasma reactors

    Microsoft Academic Search

    E. S Aydil; B. O. M Quiniou; J. T. C Lee; J. A Gregus; R. A Gottscho

    1998-01-01

    Ion incidence angle distribution on surfaces in plasma etching reactors determines the shape evolution of via holes and trenches through its effects on the spatial variation of ion fluxes along the walls of these microscopic features. We describe a novel retarding-field energy analyzer design that is capable of measuring the energy and the incidence angle distributions of ions bombarding grounded

  16. 1 Introduction Our sensory systems are constantly bombarded with a complex array of information

    E-print Network

    Shams, Ladan B.

    1 Introduction Our sensory systems are constantly bombarded with a complex array of information pertaining to our physical environment. Somehow, we are able to make sense of these inputs and structure our of the early sensory systems can be accounted for by the statistical regularities of the sensory environment

  17. Microprojectile bombardment of plant tissues increases transformation frequency by Agrobacterium tumefaciens.

    PubMed

    Bidney, D; Scelonge, C; Martich, J; Burrus, M; Sims, L; Huffman, G

    1992-01-01

    Bombardment of plant tissues with microprojectiles in an effective method of wounding to promote Agrobacterium-mediated transformation. Tobacco cv. Xanthi leaves and sunflower apical meristems were wounded by microprojectile bombardment prior to application of Agrobacterium tumefaciens strains containing genes within the T-DNA encoding GUS or NPTII. Stable kanamycin-resistant tobacco transformants were obtained using an NPTII construct from particle/plasmid, particle-wounded/Agrobacterium-treated or scalpel-wounded/Agrobacterium-treated potato leaves. Those leaves bombarded with particles suspended in TE buffer prior to Agrobacterium treatment produced at least 100 times more kanamycin-resistant colonies than leaves treated by the standard particle gun transformation protocol. In addition, large sectors of GUS expression, indicative of meristem cell transformation, were observed in plants recovered from sunflower apical explants only when the meristems were wounded first by particle bombardment prior to Agrobacterium treatment. Similar results in two different tissue types suggest that (1) particles may be used as a wounding mechanism to enhance Agrobacterium transformation frequencies, and (2) Agrobacterium mediation of stable transformation is more efficient than the analogous particle/plasmid protocol. PMID:1310058

  18. Apollo 12 Glass Spherule Ages and the Meteoroid Bombardment History of the Moon

    Microsoft Academic Search

    J. Levine; T. A. Becker; R. A. Muller; P. R. Renne

    2004-01-01

    With 5 g of soil collected by the Apollo 12 astronauts, we are continuing our study of the meteoroid bombardment history of the Moon and the inner solar system. The Moon, by virtue of its lack of water and air, preserves evidence of ancient meteoroid impacts that would quickly be eroded away or otherwise obscured on Earth. We use the

  19. Fertile transgenic Brachiaria ruziziensis (ruzigrass) plants by particle bombardment of tetraploidized callus.

    PubMed

    Ishigaki, Genki; Gondo, Takahiro; Suenaga, Kazuhiro; Akashi, Ryo

    2012-03-15

    We have produced transgenic plants of the tropical forage crop Brachiaria ruziziensis (ruzigrass) by particle bombardment-mediated transformation of multiple-shoot clumps and embryogenic calli. Cultures of multiple-shoot clumps and embryogenic calli were induced on solidified MS medium supplemented with 0.5mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 2mg/L 6-benzylaminopurine (BAP) or 4mg/L 2,4-D and 0.2mg/L BAP, respectively. Both cultures were bombarded with a vector containing an herbicide resistance gene (bar) as a selectable marker and the ?-glucuronidase (GUS) reporter gene. Sixteen hours after bombardment, embryogenic calli showed a significantly higher number of transient GUS expression spots per plate and callus than multiple-shoot clumps, suggesting that embryogenic callus is the more suitable target tissue. Following bombardment and selection with 10mg/L bialaphos, herbicide-resistant embryogenic calli regenerated shoots and roots in vitro, and mature transgenic plants have been raised in the greenhouse. Polymerase chain reaction (PCR) and DNA gel blot analysis verified that the GUS gene was integrated into the genome of the two regenerated lines. In SacI digests, the two transgenic lines showed two or five copies of GUS gene fragments, respectively, and integration at different sites. Histochemical analysis revealed stable expression in roots, shoots and inflorescences. Transgenic plants derived from diploid target callus turned out to be sterile, while transgenics from colchicine-tetraploidized callus were fertile. PMID:22236981

  20. Degradation of space exposed surfaces by hypervelocity dust bombardment, and refractory materials for space

    Microsoft Academic Search

    H. M. Ortner; F. J. Stadermann

    2009-01-01

    Dust particles with diameters below 100?m represent an important part of the space environment. Objects like satellites or spacecrafts, are constantly bombarded with particles of cosmic velocities of 10km\\/s and more. These hypervelocity impacts lead to evaporation of a large fraction of these particles and to the formation of craters on the material surfaces which exhibit diameters which are up

  1. An ultrahigh vacuum chamber for thermally stimulated conductivity measurements on ion bombarded cadmium sulphide thin films

    Microsoft Academic Search

    T. Ambridge

    1972-01-01

    An ultrahigh vacuum chamber has been constructed in which it is possible to carry out measurements of electrical conductivity and thermally stimulated conductivity on cadmium sulphide films, in order to observe and characterize the isolated defects introduced by low energy inert ion bombardment of the surface at low temperature. So that a clean surface is presented for investigation, the CdS

  2. Fast atom bombardment mass spectra of various peptides from sarcoplasmic calcium-binding protein.

    PubMed

    Aubagnac, J L; Salesse, A; Jauregui-Adell, J

    1988-10-01

    The sarcoplasmic calcium-binding protein of the crayfish Astacus leptodactylus is a calciprotein. The primary structure of this protein has been determined. Tryptic digestion of the denaturated protein followed by high-performance liquid chromatographic separation identified essentially eight peptides. The structure of these peptides has been confirmed after amino acid analysis by fast atom bombardment spectra in positive mode. PMID:3242705

  3. Sputtering of ions from Cu and Al by low energy oxygen ion bombardment

    NASA Technical Reports Server (NTRS)

    Eck, T. G.; Chen, L.-Y.; Hoffman, R. W.

    1992-01-01

    The sputtering of Cu(+) and Al(+) ions from copper and aluminum while the target surface is bombarded with low energy oxygen ions (20 to 500 eV), is investigated. Both the ion yield, as a function of oxygen ion energy, and the kinetic energy distribution of the sputtered ions at a given oxygen ion energy are determined.

  4. Nucleation enhancement of diamond films by ion bombarding and electron emitting effects

    Microsoft Academic Search

    Wang Wan-lu; Liao Ke-jun; Zhang Zhen-gang; Liao Mei-yong; M. C. Polo; G. Sanchez; J. Esteve

    1997-01-01

    Applying a proper negative bias-voltage onto the substrate, on which diamond film is deposited by chemical vapor deposition technique, can greatly improve the nucleation density. While nucleation enhancing, both the ion bombardment and electron emission may play an important role separately. However, for the highest nucleation density, both of the two effects must act together.

  5. Precision frequency trimming of SAW and STW resonators using Xe+ heavy ion bombardment

    Microsoft Academic Search

    Vladimir Shakirovich Aliev; I. D. Avramov

    1994-01-01

    A method for precision frequency trimming of surface acoustic wave (SAW) and surface transverse wave (STW) based resonant devices using a Xe+ heavy ion bombardment technique is described. The devices are downtrimmed in frequency in an in-situ monitoring process by means of a Kaufmann type ion source that allows first a rough and then a fine frequency trimming with an

  6. A review of electron bombardment thruster systems/spacecraft field and particle interfaces

    NASA Technical Reports Server (NTRS)

    Byers, D. C.

    1978-01-01

    Information on the field and particle interfaces of electron bombardment ion thruster systems was summarized. Major areas discussed were the nonpropellant particles, neutral propellant, ion beam, low energy plasma, and fields. Spacecraft functions and subsystems reviewed were solar arrays, thermal control systems, optical sensors, communications, science, structures and materials, and potential control.

  7. "Colour bombardment" - a human visual problem that interferes with the viewing of anaglyph stereo material.

    PubMed

    Barber, V C; Brett, D A

    1982-01-01

    One of the problems with the use of anaglyph stereo material is the human visual phenomenon called "colour bombardment". Certain individuals find it visually distressing to receive an image that is one colour in one eye, and another colour in the other eye, and nausea and/or vertigo are the results of even a brief exposure to such anaglyph material. The problem is not a stereo one, but is an example of the visual phenomenon called "binocular rivalry" ("retinal rivalry"). The incidence of colour bombardment was determined in the present study. Two hundred human subjects (100 male, 100 female) were given various tests, including exposure to red/green anaglyph stereo material. The recorded incidence of colour bombardment in this subject pool was 7.5%. In addition to those who suffered from colour bombardment, many of the other subjects saw the stereo material in more than a single colour. They found this sufficiently irritating as to predicate against the use of anaglyph stereo methods if satisfactory alternatives are available. PMID:7167763

  8. The surface structure of silver crystals after argon-ion bombardment

    Microsoft Academic Search

    G. Ogilvie

    1959-01-01

    Three single crystals of silver in the form of thin sheets with surfaces ; parallel to (111), (110), and (100), respectively, have been bombarded with argon ; ions at several energies in the range 12 to 4000 ev. Electron-diffraction ; patterns, taken by transmission and reflection, show short arcs and some streaks ; not present in the diagrams taken before

  9. Effect of ion bombardment on the surface magnetism of Fe3O4

    NASA Astrophysics Data System (ADS)

    Aeschlimann, M.; Bona, G. L.; Meier, F.; Stampanoni, M.; Zampieri, G.; Siegmann, H. C.

    1986-09-01

    We have found that ion bombardment produces dramatic changes in the surface magnetism of Fe3O4. The surface layer with irregular magnetic behavior is more than 50 Å thick. These findings are of importance for current studies of ferritelike sputtered thin films as well as magnetic alloys in general.

  10. Effect of ion bombardment on the surface magnetism of Fe3O4

    Microsoft Academic Search

    M. Aeschlimann; G. L. Bona; F. Meier; M. Stampanoni; G. Zampieri; H. C. Siegmann

    1986-01-01

    We have found that ion bombardment produces dramatic changes in the surface magnetism of Fe3O4. The surface layer with irregular magnetic behavior is more than 50 A? thick. These findings are of importance for current studies of ferritelike sputtered thin films as well as magnetic alloys in general.

  11. A note on the random walk theory of recoil movement in prolonged ion bombardment

    NASA Astrophysics Data System (ADS)

    Koponen, Ismo

    1994-09-01

    A characteristic function is derived for the probability distribution of final positions of recoil atoms in prolonged ion bombardment of dense matter. The derivation is done within the framework of Poissonian random walk theory using a jump distribution, which is somewhat more general than those studied previously.

  12. Angular resolved energy distributions of sputtered atoms at low bombarding energy

    Microsoft Academic Search

    A. Goehlich; D. Gillmann; H. F. Döbele

    2000-01-01

    In this contribution, measurements of energy distributions of sputtered metal atoms (tungsten and aluminum), released from polycrystalline metal targets by bombardment with noble gas ions (argon and xenon, respectively) in the energy range between 150 and 250 eV, are reported. Laser induced fluorescence spectroscopy in connection with a special designed detection geometry is applied to study energy distributions of atoms

  13. Water in the Moon: Implications for Lunar Formation, Differentiation, and Early Bombardment (Invited)

    Microsoft Academic Search

    J. Taylor

    2010-01-01

    Recent definitive discoveries that at least some lunar samples contain water indigenous to the Moon have great implications for lunar origin and subsequent differentiation and bombardment. Key observations pertinent to these issues are summarized here. (1) The water content of the lunar mantle varies considerably, from as low as undetectable (<100 ppb) to as high as tens of ppm, suggesting

  14. SPALLATION-FISSION COMPETITION IN ASTATINE COMPOUND NUCLEI FORMED BY HEAVY ION BOMBARDMENT

    Microsoft Academic Search

    T. D. Thomas; Glen Gordon; Robert Latimer; Glenn Seaborg

    1962-01-01

    Cross sections for neutron-evaporation reactions from compound nuclei ; produced by bombardment of gold with carbon ions and of platinum with nitrogen ; ions were determined. The magnitudes of the cross sections are considerably ; lower than would be predicted on the assumption that neutron emission is the only ; important mode of decay of the intermediate nuclei. This is

  15. Computer simulation of chemical erosion of graphite due to hydrogen ion bombardment

    Microsoft Academic Search

    J. H. Liang; M. Mayer; J. Roth; W. Eckstein

    2003-01-01

    Chemical erosion of graphite due to hydrogen ion bombardment has been investigated theoretically by applying a model of chemical erosion to the TRIDYN code. The model involves the formation of methane at the end of the ion track as well as the kinetic emission of hydrocarbons from the target surface. Model calculations were performed for ion energies ranging from 10

  16. Could the Lunar `Late Heavy Bombardment' Have Been Triggered by the Formation of Uranus and Neptune?

    E-print Network

    Levison, Harold F.

    Could the Lunar `Late Heavy Bombardment' Have Been Triggered by the Formation of Uranus and Neptune) of the Moon was triggered by the formation of Uranus and Neptune. As Uranus and Neptune formed, which we accreted about 6 #2; 10 21 g, if we assume that the Uranus-Neptune region initially contained 5 times

  17. DFAUTS CRS PAR BOMBARDEMENT IONIQUE DE COUCHES MINCES D'OR Par B. JOUFFREY,

    E-print Network

    Paris-Sud XI, Université de

    - ment des ions air, oxygène ou krypton. Leur éner- gie . est égale à 4 000 eV, la densité du courant dislocations. Abstract. 2014 The effects of ion bombardment on thin evaporated crystals of gold have been. At room temperature the main effect is theproduction of a great number of dislo- cation loops. Elongated

  18. Proton bombarded GaAlAs:GaAs light emitting diodes

    Microsoft Academic Search

    J. Heinen; H. Westermeier; W. Harth; K. H. Zschauer

    1976-01-01

    High-speed high-radiance luminescent diodes for optical transmission systems have been fabricated. Proton bombardment is used for confining the area of the active region. Modulation cutoff frequencies of 170 MHz and a radiance of 11 W\\/ sr. cm2at a diode current of 100 mA have been measured.

  19. Polaron pair mediated triplet generation in polymer/fullerene blends

    NASA Astrophysics Data System (ADS)

    Dimitrov, Stoichko D.; Wheeler, Scot; Niedzialek, Dorota; Schroeder, Bob C.; Utzat, Hendrik; Frost, Jarvist M.; Yao, Jizhong; Gillett, Alexander; Tuladhar, Pabitra S.; McCulloch, Iain; Nelson, Jenny; Durrant, James R.

    2015-03-01

    Electron spin is a key consideration for the function of organic semiconductors in light-emitting diodes and solar cells, as well as spintronic applications relying on organic magnetoresistance. A mechanism for triplet excited state generation in such systems is by recombination of electron-hole pairs. However, the exact charge recombination mechanism, whether geminate or nongeminate and whether it involves spin-state mixing is not well understood. In this work, the dynamics of free charge separation competing with recombination to polymer triplet states is studied in two closely related polymer-fullerene blends with differing polymer fluorination and photovoltaic performance. Using time-resolved laser spectroscopic techniques and quantum chemical calculations, we show that lower charge separation in the fluorinated system is associated with the formation of bound electron-hole pairs, which undergo spin-state mixing on the nanosecond timescale and subsequent geminate recombination to triplet excitons. We find that these bound electron-hole pairs can be dissociated by electric fields.

  20. Preparation and biodistribution of radiolabeled fullerene C60 nanocrystals

    NASA Astrophysics Data System (ADS)

    Nikoli?, Nadežda; Vranješ-Ðuri?, Sanja; Jankovi?, Drina; Ðoki?, Divna; Mirkovi?, Marija; Bibi?, Nataša; Trajkovi?, Vladimir

    2009-09-01

    The present study describes for the first time a procedure for the radiolabeling of fullerene (C60) nanocrystals (nanoC60) with Na 125I, as well as the biodistribution of radiolabeled nanoC60 (125I-nanoC60). The solvent exchange method with tetrahydrofuran was used to make colloidal water suspensions of radiolabeled nanoC60 particles. The radiolabeling procedure with the addition of Na 125I to tetrahydrofuran during dissolution of C60 gave a higher radiochemical yield of radiolabeled nanoC60 particles in comparison to the second option, in which Na 125I was added after C60 was dissolved. Using photon correlation spectroscopy and transmission electron microscopy, 125I-nanoC60 particles were found to have a crystalline structure and a mean diameter of 200-250 nm. The 125I-nanoC60 had a particularly high affinity for human serum albumin, displaying 95% binding efficiency after 1 h. Biodistribution studies of 125I-nanoC60 in rats indicated significant differences in tissue accumulation of 125I-nanoC60 and the radioactive tracer Na 125I. The higher accumulation of radiolabeled nanoC60 was observed in liver and spleen, while accumulation in thyroid, stomach, lungs and intestines was significantly lower in comparison to Na 125I. In addition to being useful for testing the biological distribution of nanoC60, the described radiolabeling procedure might have possible applications in cancer radiotherapy.

  1. Liquid phase deposition of silica: Thin films, colloids and fullerenes

    NASA Astrophysics Data System (ADS)

    Whitsitt, Elizabeth A.

    Little research has been done to explore liquid phase deposition (LPD) of silica on non-planar substrates. This thesis proves that the seeded growth of silica colloids from fullerene and surfactant micelles is possible via LPD, as is the coating of individual single walled carbon nanotubes (SWNTs) and carbon fibers. Working on the premise that a molecular growth mechanism (versus colloidal/gel deposition) is valid for LPD, nanostructured substrates and specific chemical functional groups should act as "seeds," or templates, for silica growth. Seeded growth is confirmed by reactions of the growth solution with a range of surfactants and with materials with distinctive surface moieties. LPD promises lower production costs and environmental impact as compared to present methods of coating technology, because it is an inherently simple process, using low temperatures and inexpensive air-stable reactants. Silica is ubiquitous in materials science. Its applications range from thixotropic additives for paint to gate dielectrics in the semiconductor industry. Nano-structured coatings and thin films are integral in today's electronics industry and will become more vital as the size of electronics shrinks. With the incorporation of nanoparticles in future devices, the ability to deposit quality coatings with finely tuned properties becomes paramount. The methods developed herein have applications in fabricating insulators for use in the future molecular scale electronics industry. Additionally, these silica nanoparticles have applications as templates for use in photonics and fuel cell membrane production and lend strength and durability to composites.

  2. Top-down formation of fullerenes in the interstellar medium

    E-print Network

    Berne, O; Joblin, C

    2015-01-01

    [Abridged] Fullerenes have been recently detected in various circumstellar and interstellar environments, raising the question of their formation pathway. It has been proposed that they can form by the photo-chemical processing of large polycyclic aromatic hydrocarbons (PAHs). Following our previous work on the evolution of PAHs in the NGC 7023 reflection nebula, we evaluate, using photochemical modeling, the possibility that the PAH C$_{66}$H$_{20}$ (i.e. circumovalene) can lead to the formation of C$_{60}$ upon irradiation by ultraviolet photons. The chemical pathway involves full dehydrogenation, folding into a floppy closed cage and shrinking of the cage by loss of C$_2$ units until it reaches the symmetric C$_{60}$ molecule. At 10" from the illuminating star and with realistic molecular parameters, the model predicts that 100\\% of C$_{66}$H$_{20}$ is converted into C$_{60}$ in $\\sim$ 10$^5$ years, a timescale comparable to the age of the nebula. Shrinking appears to be the kinetically limiting step of th...

  3. Polaron pair mediated triplet generation in polymer/fullerene blends

    PubMed Central

    Dimitrov, Stoichko D.; Wheeler, Scot; Niedzialek, Dorota; Schroeder, Bob C.; Utzat, Hendrik; Frost, Jarvist M.; Yao, Jizhong; Gillett, Alexander; Tuladhar, Pabitra S.; McCulloch, Iain; Nelson, Jenny; Durrant, James R.

    2015-01-01

    Electron spin is a key consideration for the function of organic semiconductors in light-emitting diodes and solar cells, as well as spintronic applications relying on organic magnetoresistance. A mechanism for triplet excited state generation in such systems is by recombination of electron-hole pairs. However, the exact charge recombination mechanism, whether geminate or nongeminate and whether it involves spin-state mixing is not well understood. In this work, the dynamics of free charge separation competing with recombination to polymer triplet states is studied in two closely related polymer-fullerene blends with differing polymer fluorination and photovoltaic performance. Using time-resolved laser spectroscopic techniques and quantum chemical calculations, we show that lower charge separation in the fluorinated system is associated with the formation of bound electron-hole pairs, which undergo spin-state mixing on the nanosecond timescale and subsequent geminate recombination to triplet excitons. We find that these bound electron-hole pairs can be dissociated by electric fields. PMID:25735188

  4. Fullerene derivatives induce premature senescence: A new toxicity paradigm or novel biomedical applications

    SciTech Connect

    Gao Jun [Biosciences Division, Los Alamos National Laboratory, M888, TA 43, HRL-2, Los Alamos, NM 87545 (United States); Wang, H.L. [Chemistry Division, Los Alamos National Laboratory, J567, TA 46, Los Alamos, NM 87545 (United States); Shreve, Andrew [Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, P.O. Box 1663, MS K771, Los Alamos, NM 87545 (United States); Iyer, Rashi, E-mail: rashi@lanl.go [Biosciences Division, Los Alamos National Laboratory, M888, TA 43, HRL-2, Los Alamos, NM 87545 (United States)

    2010-04-15

    Engineered fullerenes (C{sub 60}) are extensively used for commercial and clinical applications based on their unique physicochemical properties. Such materials have also been recognized as byproducts of many industrial activities. Functionalization of C{sub 60} may significantly influence the nature of its interactions with biological systems, impacting its applications and raising uncertainties about its health effects. In the present study, we compared the bioimpact of two chemically modified fullerene derivatives, hexa carboxyl fullerene adduct (Hexa-C{sub 60}) and tris carboxyl fullerene adduct (tris-C{sub 60}) to pristine fullerene C{sub 60} encapsulated with gamma (gamma)-cyclodextrin C{sub 60} (CD-C{sub 60}), using human cutaneous epithelial cells (HEK) to simulate possible applications and occupational dermal exposure route. We report, for the first time, the discovery of premature senescence as a potential endpoint of nanomaterial elicited biological effects, providing a new paradigm for nanoparticle-induced toxicity in human cells. Moreover, this response appeared to be functionalization specific, in that, only tris-C{sub 60} induced senescence. We investigated key biological responses, such as cellular viability, intracellular ROS generation, cell proliferation and cell cycle responses. Our results indicate that the often observed 'anti-apoptotic' function of fullerene derivatives may be independent of their 'ROS scavenging' role as previously reported. We discovered that the tris-C{sub 60}-induced responses were associated with G{sub 0}/G{sub 1} cell cycle arrest and cellular senescence. On further evaluation of the molecular mechanisms underlying the senescent response, a significant decrease in the expression levels of HERC5 was noted. HERC5 is a ubiquitin ligase of the HERC family and is implicated to be involved in innate immune responses to viral and bacterial infections.

  5. Hydrogen pumping and release by graphite under high flux plasma bombardment

    SciTech Connect

    Hirooka, Y.; Leung, W.K.; Conn, R.W.; Goebel, D.M.; LaBombard, B.; Nygren, R.; Wilson, K.L.

    1988-01-01

    Inert gas (helium or argon) plasma bombardment has been found to increase the surface gas adsorptivity of isotropic graphite (POCO-graphite), which can then getter residual gases in a high vacuum system. The inert gas plasma bombardment was carried out at a flux approx. = 1 x 10/sup 18/ ions s/sup -1/ cm/sup -2/ to a fluence of the order of 10/sup 21/ ions/cm/sup 2/ and at temperatures around 800/sup 0/C. The gettering capability of graphite can be easily recovered by repeating inert gas plasma bombardment. The activated graphite surface exhibits a smooth, sponge-like morphology with significantly increased pore openings, which correlates with the observed increase in the surface gas adsorptivity. The activated graphite surface has been observed to pump hydrogen plasma particles as well. From calibrated H-alpha measurements, the dynamic hydrogen retention capacity is evaluated to be as large as 2 x 10/sup 18/ H/cm/sup 2/ at temperatures below 100/sup 0/C and at a plasma bombarding energy of 300 eV. The graphite temperature was varied between 15 and 480/sup 0/C. Due to the plasma particle pumping capability, hydrogen recycling from the activated graphite surface is significantly reduced, relative to that from a pre-saturated surface. A pre-saturated surface was also observed to reproducibly pump a hydrogen plasma to a concentration of 9.5 x 10/sup 17/ H/cm/sup 2/. The hydrogen retention capacity of graphite is found to decrease with increasing temperature. A transient pumping mechanism associated with the sponge-like surface morphology is conjectured to explain the large hydrogen retention capacity. Hydrogen release behavior under helium and argon plasma bombardment was also investigated, and the result indicated the possibility of some in-pore retrapping effect. 43 refs., 11 figs.

  6. [C72]—Fullerene: Enumeration of Substitution Isomers Based on the Vertex, Edge and Facial Differentiation

    NASA Astrophysics Data System (ADS)

    Smolyakov, V. M.; Sokolov, D. V.; Nilov, D. Yu.; Grebeshkov, V. V.; Bolshakov, V. V.

    2010-11-01

    The paper discusses substitution isomers [C72]—fullerene by vertices, edges and faces. The derivation of isomers is based on the Polya theorem [1]. Formulas of symmetry Z, generating functions for identification of the number of substitution isomers of [C72]—fullerene, distribution of isomers over families ?(m) and depending on number m of places of substitution is established. Based on the models [2-5] an addictive assessment scheme of the properties of gaseous carbon clusters [C60]-[C100] is obtained, and calculations of gaseous carbon clusters ?fH° 298?, S° 298? not studied experimentally yet, are carried out.

  7. The readout of the fullerene-based quantum computing by a scanning tunneling microscope

    E-print Network

    M. Feng; G. J. Dong; B. Hu

    2006-10-11

    We consider to detect the electron spin of a doped atom, i.e., a nitrogen or a phosphorus, caged in a fullerene by currently available technique of the scanning tunneling microscope (STM), which actually corresponds to the readout of a qubit in the fullerene-based quantum computing. Under the conditions of polarized STM current and Coulomb blockade, we investigate the tunneling matrix elements involving the exchange coupling between the tunneling polarized electrons and the encapsulated polarized electron, and calculate the variation of the tunneling current with respect to different orientations of the encapsulated electron spin. The experimental feasibility of our scheme is discussed under the consideration of some imperfect factors.

  8. POLARON DYNAMICS. Long-lived photoinduced polaron formation in conjugated polyelectrolyte-fullerene assemblies.

    PubMed

    Huber, Rachel C; Ferreira, Amy S; Thompson, Robert; Kilbride, Daniel; Knutson, Nicholas S; Devi, Lekshmi Sudha; Toso, Daniel B; Challa, J Reddy; Zhou, Z Hong; Rubin, Yves; Schwartz, Benjamin J; Tolbert, Sarah H

    2015-06-19

    The efficiency of biological photosynthesis results from the exquisite organization of photoactive elements that promote rapid movement of charge carriers out of a critical recombination range. If synthetic organic photovoltaic materials could mimic this assembly, charge separation and collection could be markedly enhanced. We show that micelle-forming cationic semiconducting polymers can coassemble in water with cationic fullerene derivatives to create photoinduced electron-transfer cascades that lead to exceptionally long-lived polarons. The stability of the polarons depends on the organization of the polymer-fullerene assembly. Properly designed assemblies can produce separated polaronic charges that are stable for days or weeks in aqueous solution. PMID:26089510

  9. Theory of normal and superconducting properties of fullerene-based solids

    SciTech Connect

    Cohen, M.L.

    1992-10-01

    Recent experiments on the normal-state and superconducting properties of fullerene-based solids are used to constrain the proposal theories of the electronic nature of these materials. In general, models of superconductivity based on electron pairing induced by phonons are consistent with electronic band theory. The latter experiments also yield estimates of the parameters characterizing these type H superconductors. It is argued that, at this point, a ``standard model`` of phonons interacting with itinerant electrons may be a good first approximation for explaining the properties of the metallic fullerenes.

  10. Theory of normal and superconducting properties of fullerene-based solids

    SciTech Connect

    Cohen, M.L.

    1992-10-01

    Recent experiments on the normal-state and superconducting properties of fullerene-based solids are used to constrain the proposal theories of the electronic nature of these materials. In general, models of superconductivity based on electron pairing induced by phonons are consistent with electronic band theory. The latter experiments also yield estimates of the parameters characterizing these type H superconductors. It is argued that, at this point, a standard model'' of phonons interacting with itinerant electrons may be a good first approximation for explaining the properties of the metallic fullerenes.

  11. Strategies for quantifying C60 fullerenes in environmental and biological samples and implications for studies in environmental health and ecotoxicology

    PubMed Central

    Pycke, Benny F.G.; Benn, Troy M.; Herckes, Pierre; Westerhoff, Paul; Halden, Rolf U.

    2010-01-01

    Fullerenes are sphere-like molecules with unique physico-chemical properties, which render them of particular interest in biomedical research, consumer products and industrial applications. Human and environmental exposure to fullerenes is not a new phenomenon, due to a long history of hydrocarbon-combustion sources, and will only increase in the future, as incorporation of fullerenes into consumer products becomes more widespread for use as anti-aging, anti-bacterial or anti-apoptotic agents. An essential step in the determination of biological effects of fullerenes (and their surface-functionalized derivatives) is establishment of exposure-assessment techniques. However, in ecotoxicological studies, quantification of fullerenes is performed infrequently because robust, uniformly applicable analytical approaches have yet to be identified, due to the wide variety of sample types. Moreover, the unique physico-chemistry of fullerenes in aqueous matrices requires reassessment of conventional analytical approaches, especially in more complex biological matrices (e.g., urine, blood, plasma, milk, and tissue). Here, we present a review of current analytical approaches for the quantification of fullerenes and propose a consensus approach for determination of these nanomaterials in a variety of environmental and biological matrices. PMID:21359100

  12. Molecular packing and electronic processes in amorphous-like polymer bulk heterojunction solar cells with fullerene intercalation.

    PubMed

    Xiao, Ting; Xu, Haihua; Grancini, Giulia; Mai, Jiangquan; Petrozza, Annamaria; Jeng, U-Ser; Wang, Yan; Xin, Xin; Lu, Yong; Choon, Ng Siu; Xiao, Hu; Ong, Beng S; Lu, Xinhui; Zhao, Ni

    2014-01-01

    The interpenetrating morphology formed by the electron donor and acceptor materials is critical for the performance of polymer:fullerene bulk heterojunction (BHJ) photovoltaic (PV) cells. In this work we carried out a systematic investigation on a high PV efficiency (>6%) BHJ system consisting of a newly developed 5,6-difluorobenzo[c] thiadiazole-based copolymer, PFBT-T20TT, and a fullerene derivative. Grazing incidence X-ray scattering measurements reveal the lower-ordered nature of the BHJ system as well as an intermixing morphology with intercalation of fullerene molecules between the PFBT-T20TT lamella. Steady-state and transient photo-induced absorption spectroscopy reveal ultrafast charge transfer (CT) at the PFBT-T20TT/fullerene interface, indicating that the CT process is no longer limited by exciton diffusion. Furthermore, we extracted the hole mobility based on the space limited current (SCLC) model and found that more efficient hole transport is achieved in the PFBT-T20TT:fullerene BHJ as compared to pure PFBT-T20TT, showing a different trend as compared to the previously reported highly crystalline polymer:fullerene blend with a similar intercalation manner. Our study correlates the fullerene intercalated polymer lamella morphology with device performance and provides a coherent model to interpret the high photovoltaic performance of some of the recently developed weakly-ordered BHJ systems based on conjugated polymers with branched side-chain. PMID:24909640

  13. A keV string axion from high scale supersymmetry

    NASA Astrophysics Data System (ADS)

    Henning, Brian; Kehayias, John; Murayama, Hitoshi; Pinner, David; Yanagida, Tsutomu T.

    2015-02-01

    Various theoretical and experimental considerations motivate models with high-scale supersymmetry breaking. While such models may be difficult to test in colliders, we propose looking for signatures at much lower energies. We show that a keV line in the x-ray spectrum of galaxy clusters (such as the recently disputed 3.5-keV observation) can have its origin in a universal string axion coupled to a hidden supersymmetry breaking sector. A linear combination of the string axion and an additional axion in the hidden sector remains light, obtaining a mass of order 10 keV through supersymmetry breaking dynamics. In order to explain the x-ray line, the scale of supersymmetry breaking must be about 1 011 - 12 GeV . This motivates high-scale supersymmetry as in pure gravity mediation or minimal split supersymmetry and is consistent with all current limits. Since the axion mass is controlled by a dynamical mass scale, this mass can be much higher during inflation, avoiding isocurvature (and domain wall) problems associated with high-scale inflation. In an appendix, we present a mechanism for dilaton stabilization that additionally leads to O (1 ) modifications of the gaugino mass from anomaly mediation.

  14. Ultrafast 25 keV backlighting for experiments on Z.

    SciTech Connect

    Sefkow, Adam B.; Atherton, Briggs W.; Geissel, Matthias; Schollmeier, Marius; Pitts, Todd Alan; Rambo, Patrick K.; Schwarz, Jens; Kimmel, Mark W.

    2010-11-01

    To extend the backlighting capabilities for Sandia's Z-Accelerator, Z-Petawatt, a laser which can provide laser pulses of 500 fs length and up to 120 J (100TW target area) or up to 450 J (Z / Petawatt target area) has been built over the last years. The main mission of this facility focuses on the generation of high energy X-rays, such as tin Ka at 25 keV in ultra-short bursts. Achieving 25 keV radiographs with decent resolution and contrast required addressing multiple problems such as blocking of hot electrons, minimization of the source, development of suitable filters, and optimization of laser intensity. Due to the violent environment inside of Z, an additional very challenging task is finding massive debris and radiation protection measures without losing the functionality of the backlighting system. We will present the first experiments on 25 keV backlighting including an analysis of image quality and X-ray efficiency.

  15. Towards perfunctionalized dodecahedranes--en route to C20 fullerene.

    PubMed

    Wahl, Fabian; Weiler, Andreas; Landenberger, Peter; Sackers, Emmerich; Voss, Torsten; Haas, Alois; Lieb, Max; Hunkler, Dieter; Wörth, Jürgen; Knothe, Lothar; Prinzbach, Horst

    2006-08-16

    "One-pot" substitution of the twenty hydrogen atoms in pentagonal dodecahedrane (C(20)H(20)) by OH, F, Cl, and Br atoms is explored. Electrophilic insertion of oxygen atoms with DMDO and TFMDO as oxidizing reagents ended, far off the desired C(20)(OH)(20), in complex polyol mixtures (up to C(20)H(10)(OH)(10) decols, a trace of C(20)H(OH)(19)?). Perfluorination was successful in a NaF matrix but (nearly pure) C(20)F(20) could be secured only in very low yield. "Brute-force" photochlorination (heat, light, pressure, time) provided a mixture of hydrogen-free, barely soluble C(20)Cl(16) dienes in high yield and C(20)Cl(20) as a trace component. Upon electron-impact ionization of the C(20)Cl(16) material sequential loss of the chlorine atoms was the major fragmentation pathway furnishing, however, only minor amounts of chlorine-free C(20) (+) ions. "Brute-force" photobrominations delivered an extremely complex mixture of polybromides with C(20)HBr(13) trienes as the highest masses. The MS spectra exhibited exclusive loss of the Br substituents ending in rather intense singly, doubly, and triply charged C(20)H(4-0) (+(2+)(3+)) ions. The insoluble approximately C(20)HBr(13) fraction (C(20)Br(14) trienes as highest masses) obtained along a modified bromination protocol, ultimately allowed the neat mass selection of C(20) (-) ions. The C(20)Cl(16) dienes and C(20)H(0-3)Br(14-12) tri-/tetraenes, in spite of their very high olefinic pyramidalization, proved resistant to oxygen and dimerization (polymerization) but added CH(2)N(2) smoothly. Dehalogenation of the respective cycloaddition products through electron-impact ionization resulted in C(22-24)H(4-8) (+(2+)) ions possibly constituting bis-/tris-/tetrakis-methano-C(20) fullerenes or partly hydrogenated C(22), C(23), and C(24) cages. PMID:16807931

  16. Polythermal study of the solubility of fullerenes in pelargonic and caprylic acids

    Microsoft Academic Search

    K. N. Semenov; N. A. Charykov; A. K. Pyartman; V. A. Keskinov; O. V. Arapov; N. I. Alekseev; V. V. Lishchuk

    2007-01-01

    A polythermal study of the solubility of C60 and a fullerene mixture (60% C60 + 39% C70 + 1% C76–C90) in pelargonic and caprylic acids was carried out at 20–80C. The solubility polytherms are given and discussed.

  17. The solubility of fullerenes in butyric and enanthic acids at 20–80 °C

    Microsoft Academic Search

    K. N. Semenov; N. A. Charykov; A. K. Pyartman; V. A. Keskinov; O. V. Arapov; N. I. Alekseev; V. V. Lishchuk

    2008-01-01

    The polythermal solubility of C60 and fullerene mixture (60% C60, 39% C70, and 1% C76–90) in butyric and enanthic acids was studied over the temperature range 20–80 °C. The corresponding solubility polytherms are\\u000a given and characterized.

  18. Hiding and recovering electrons in a dimetallic endohedral fullerene: air-stable products from radical additions.

    PubMed

    Yamada, Michio; Kurihara, Hiroki; Suzuki, Mitsuaki; Saito, Masayoshi; Slanina, Zdenek; Uhlik, Filip; Aizawa, Toshihiro; Kato, Tatsuhisa; Olmstead, Marilyn M; Balch, Alan L; Maeda, Yutaka; Nagase, Shigeru; Lu, Xing; Akasaka, Takeshi

    2015-01-14

    Fullerenyl radicals can be generated by addition of a free radical to a fullerene surface, by nucleophilic addition followed by one-electron oxidation, or by thermal dissociation of singly bonded fullerene dimers. However, fullerenyl radicals are usually very reactive and generally cannot be isolated. On the contrary, we have found that the reactions of the dimetallic endofullerenes, La2@Ih-C80 and La2@D5h-C80, with 3-chloro-5,6-diphenyltriazine resulted in mono-addition of the triazinyl radical to the fullerene cages to yield isolable fullerenyl radicals. The unusual stability of these fullerenyl radicals arises from the confinement of the unpaired electron to an internal, metal-metal bonding orbital. Accordingly, the fullerene cage protects the radical center from other reactive species. Furthermore, we demonstrate that the fullerenyl radical adduct of La2@Ih-C80 reacts with toluene to afford additional benzylation. Interestingly, the benzylated derivative is diamagnetic in solution, while it forms a paramagnetic dimer when crystallized. PMID:25494409

  19. Fullerene-Polyhedral Oligosilsesquioxane Organic-Inorganic Hybrids and Applications as a Nanolayered Supercapacitor

    NASA Astrophysics Data System (ADS)

    Tu, Yingfeng; Ye, Chun; Zhang, Wenbin; Tsai, Chi-Chun; Sun, Bin; Li, Xiaohong; Cheng, Stephen Z. D.

    2009-03-01

    Fullerenes and polyhedral oligomeric silsesquioxane (POSS) organic-inorganic hybrid material was synthesized by esterification of methano[60]fullerene carboxylic acid (MFCA) with POSS-OH. The chemical structure was characterized and proven by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), SEC and UV-Vis spectroscopy. The material has high solubility (more than 10%) in solvents like toluene, THF, chloroform and hexane. The material has high thermal stability: only 1% of total mass lost at 350 C and 50% at 800 C. At high concentrations, the solution of fullerene-POSS can absorb nearly the full spectra of the UV-Vis region (200 nm-700 nm). Crystals can be grown from chloroform solution, and the crystal structure was determined by transmission electron microscopy (TEM) and x-ray diffraction as an orthorhombic structure with a = 2.10 nm, b = 1.06 nm and c = 3.71 nm. This indicates a bilayer structure. The alternating layered structure of fullerene (conductive) and POSS (insulating) in the crystal can be used for applications such as supercapacitors.

  20. Fullerene mixing effect on carrier formation in bulk-hetero organic solar cell

    NASA Astrophysics Data System (ADS)

    Moritomo, Yutaka; Yasuda, Takeshi; Yonezawa, Kouhei; Sakurai, Takeaki; Takeichi, Yasuo; Suga, Hiroki; Takahashi, Yoshio; Inami, Nobuyuki; Mase, Kazuhiko; Ono, Kanta

    2015-03-01

    Organic solar cells (OSCs) with a bulk-heterojunction (BHJ) are promising energy conversion devices, because they are flexible and environmental-friendly, and can be fabricated by low-cost roll-to-roll process. Here, we systematically investigated the interrelations between photovoltaic properties and the domain morphology of the active layer in OSCs based on films of poly-(9,9-dioctylfluorene-co-bithiophene) (F8T2)/[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) blend annealed at various temperatures (Tan). The scanning transmission X-ray microscopy (STXM) revealed that fullerene mixing (?Fullerene) in the polymer matrix decreases with increase in Tan while the domain size (L) is nearly independent of Tan. The TEM-S mapping image suggests that the polymer matrix consist of polymer clusters of several nm and fullerene. We found that the charge formation efficiency (?CF), internal quantum efficiency (?IQ), and power conversion efficiency (PCE) are dominantly determined by ?Fullerene. We interpreted these observations in terms of the polymer clusters within the polymer matrix.