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Sample records for intercalator displacement-based discovery

  1. DISPLACEMENT BASED SEISMIC DESIGN METHODS.

    SciTech Connect

    HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.

    2003-07-15

    A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.

  2. Displacement Based Seismic Design Criteria

    SciTech Connect

    Costello, J.F.; Hofmayer, C.; Park, Y.J.

    1999-03-29

    The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

  3. DISPLACEMENT BASED SEISMIC DESIGN CRITERIA

    SciTech Connect

    HOFMAYER,C.H.

    1999-03-29

    The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

  4. Harnessing DNA intercalation.

    PubMed

    Persil, Ozgül; Hud, Nicholas V

    2007-10-01

    Numerous small molecules are known to bind to DNA through base pair intercalation. Fluorescent dyes commonly used for nucleic acid staining, such as ethidium, are familiar examples. Biological and physical studies of DNA intercalation have historically been motivated by mutation and drug discovery research. However, this same mode of binding is now being harnessed for the creation of novel molecular assemblies. Recent studies have used DNA scaffolds and intercalators to construct supramolecular assemblies that function as fluorescent 'nanotags' for cell labeling. Other studies have demonstrated how intercalators can be used to promote the formation of otherwise unstable nucleic acid assemblies. These applications illustrate how intercalators can be used to facilitate and expand DNA-based nanotechnology. PMID:17825446

  5. Discovery

    ERIC Educational Resources Information Center

    de Mestre, Neville

    2010-01-01

    All common fractions can be written in decimal form. In this Discovery article, the author suggests that teachers ask their students to calculate the decimals by actually doing the divisions themselves, and later on they can use a calculator to check their answers. This article presents a lesson based on the research of Bolt (1982).

  6. Graphene spintronics: Intercalated boosters

    NASA Astrophysics Data System (ADS)

    Kralj, Marko

    2015-01-01

    Graphene is a candidate spintronics material, but its weak intrinsic spin-orbit coupling is problematic. Intercalating graphene on an iridium substrate with islands of lead is now shown to induce a strong, spatially varying spin-orbit coupling.

  7. Measurement of chest wall displacement based on terahertz wave

    NASA Astrophysics Data System (ADS)

    Li, Hui; Lv, Hao; Jiao, Teng; Lu, Guohua; Li, Sheng; Li, Zhao; Liu, Miao; Jing, Xijing; Wang, Jianqi

    2015-02-01

    Measurement of chest wall displacement is an important approach for measuring mechanics of chest wall, which has considerable significance for assessing respiratory system and diagnosing pulmonary diseases. However, existing optical methods for measuring chest wall displacement are inconvenient for some specific patients such as the female patients and the patients with bandaged chest. In this letter, we proposed a method for measuring chest wall displacement based on terahertz wave and established corresponding mathematic model and set up a terahertz measurement system. The main advantages of this method are that it can measure the chest wall displacement of the subjects without taking off clothes or arranging any markers. To validate this method and assess the performance of the terahertz system, in vitro, the displacement of a water module driven by a linear guide rail was measured by the terahertz system and compared with the actual displacement of the water module. The results showed that the waveforms measured with two methods have a good agreement, and the relative error is less than 5% and sufficiently good for measurement demands. In vivo, the synchronous experiment was performed on five human volunteers with the terahertz system and a respiratory belt transducer. The results demonstrate that this method has good performance and promising prospects for measuring chest wall displacement.

  8. Superconductivity in graphite intercalation compounds

    SciTech Connect

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P. M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  9. Superconductivity in graphite intercalation compounds

    DOE PAGESBeta

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P. M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic statesmore » and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.« less

  10. Efficiency Improvements to the Displacement Based Multilevel Structural Optimization Algorithm

    NASA Technical Reports Server (NTRS)

    Plunkett, C. L.; Striz, A. G.; Sobieszczanski-Sobieski, J.

    2001-01-01

    Multilevel Structural Optimization (MSO) continues to be an area of research interest in engineering optimization. In the present project, the weight optimization of beams and trusses using Displacement based Multilevel Structural Optimization (DMSO), a member of the MSO set of methodologies, is investigated. In the DMSO approach, the optimization task is subdivided into a single system and multiple subsystems level optimizations. The system level optimization minimizes the load unbalance resulting from the use of displacement functions to approximate the structural displacements. The function coefficients are then the design variables. Alternately, the system level optimization can be solved using the displacements themselves as design variables, as was shown in previous research. Both approaches ensure that the calculated loads match the applied loads. In the subsystems level, the weight of the structure is minimized using the element dimensions as design variables. The approach is expected to be very efficient for large structures, since parallel computing can be utilized in the different levels of the problem. In this paper, the method is applied to a one-dimensional beam and a large three-dimensional truss. The beam was tested to study possible simplifications to the system level optimization. In previous research, polynomials were used to approximate the global nodal displacements. The number of coefficients of the polynomials equally matched the number of degrees of freedom of the problem. Here it was desired to see if it is possible to only match a subset of the degrees of freedom in the system level. This would lead to a simplification of the system level, with a resulting increase in overall efficiency. However, the methods tested for this type of system level simplification did not yield positive results. The large truss was utilized to test further improvements in the efficiency of DMSO. In previous work, parallel processing was applied to the

  11. Thin flexible intercalation anodes

    SciTech Connect

    Levy, S.C.; Cieslak, W.R.; Klassen, S.E.; Lagasse, R.R.

    1994-10-01

    Poly(acrylonitrile) fibers have been pyrolyzed under various conditions to form flexible carbon yarns capable of intercalating lithium ions. These fibers have also been formed into both woven and non woven cloths. Potentiostatic, potentiodynamic and galvanostatic tests have been conducted with these materials in several electrolytes. In some tests, a potential hold was used after each constant current charge and discharge. These tests have shown some of these flexible materials to reversibly intercalate lithium ions to levels that are suitable for use as a practical battery anode.

  12. Graphite fiber intercalation: Dynamics of the bromine intercalation process

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Zinolabedini, R.

    1985-01-01

    The resistance of pitch-based graphite fibers was monitored, in situ, during a series of bromine intercalation experiments. The threshold pressure for the bromine intercalation of pitch-based fibers was estimated to be 102 torr. When the bromine atmosphere was removed from the reaction chamber, the resistivity of the intercalated graphite fibers increased consistently. This increase was attributed to loss of bromine from the perimeter of the fiber. The loss was confirmed by mapping the bromine concentration across the diameter of single intercalated fibers with either energy dispersive spectroscopy or scanning Auger microscopy. A statistical study comparing fibers intercalated in bromine vapor with fibers intercalated in bromine liquid showed that similar products were obtained with both methods of intercalation.

  13. Photofunctions of intercalation compounds

    SciTech Connect

    Ogawa, Makoto; Kuroda, Kazuyuki

    1995-03-01

    In this article, the authors review the studies on the photofunctions of intercalation compounds. (The structures and properties of host materials which have been used for immobilizing photoactive species have been summarized in the following section.) some of these studies are for the purpose of characterizing the properties of host materials and host-guest systems, and others are for the purpose of contributing to future practical applications. The well-defined layered structures as well as the ability to accommodate guest species on the surface of the layers are very useful for organizing photoactive species to evaluate and control the photofunctions. Table 1 summarizes the characteristics of typical host-guest systems studied for immobilizing photoactive species. Attention is mainly focused on the role of layered structure on the organization of photoactive species; the photofunctions of intercalation compounds are discussed only in connection with the microscopic structures. 321 refs.

  14. Intercalating oleylamines in graphite oxide.

    PubMed

    Yang, Kaikun; Liang, Si; Zou, Lianfeng; Huang, Liwei; Park, Cheol; Zhu, Lisheng; Fang, Jiye; Fu, Qiang; Wang, Howard

    2012-02-01

    Graphite oxide has been synthesized from raw graphite particles and been treated with various mass amounts of oleylamine as intercalants to form intercalation compounds. X-ray diffraction patterns reveal that the inter-sheet distances strongly depend on the graphite oxide to oleylamine mass ratios. The equilibrium-like behavior implies diffusion-dominated oleylamine adsorption on graphite oxide in solution and excluded volume intercalations among oleylamine-adsorbed graphite oxide during restacking. The intercalation compounds are soluble in organic solvents, and their applications in the fabrication of transparent and conductive coatings have been demonstrated. PMID:22229856

  15. Stacking interactions and DNA intercalation

    SciTech Connect

    Li, Dr. Shen; Cooper, Valentino R; Thonhauser, Prof. Timo; Lundqvist, Prof. Bengt I.; Langreth, David C.

    2009-01-01

    The relationship between stacking interactions and the intercalation of proflavine and ellipticine within DNA is investigated using a nonempirical van der Waals density functional for the correlation energy. Our results, employing a binary stack model, highlight fundamental, qualitative differences between base-pair base-pair interactions and that of the stacked intercalator base pair system. Most notable result is the paucity of torque which so distinctively defines the Twist of DNA. Surprisingly, this model, when combined with a constraint on the twist of the surrounding base-pair steps to match the observed unwinding of the sugar-phosphate backbone, was sufficient for explaining the experimentally observed proflavine intercalator configuration. Our extensive mapping of the potential energy surface of base-pair intercalator interactions can provide valuable information for future nonempirical studies of DNA intercalation dynamics.

  16. Durability of Intercalated Graphite Epoxy Composites in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Davidson, Michelle L.; Shively, Rhonda

    1996-01-01

    The electrical conductivity of graphite epoxy composites can be substantially increased by intercalating (inserting guest atoms or molecules between the graphene planes) the graphite fibers before composite formation. The resulting high strength, low density, electrically conducting composites have been proposed for EMI shielding in spacecraft. Questions have been raised, however, about their durability in the space environment, especially with respect to outgassing of the intercalates, which are corrosive species such as bromine. To answer those concerns, six samples of bromine intercalated graphite epoxy composites were included in the third Evaluation of Oxygen Interaction with Materials (EOIM-3) experiment flown on the Space Shuttle Discovery (STS-46). Changes in electrical conductivity, optical reflectance, surface texture, and mass loss for SiO2 protected and unprotected samples were measured after being exposed to the LEO environment for 42 hours. SiO2 protected samples showed no degradation, verifying conventional protection strategies are applicable to bromine intercalated composites. The unprotected samples showed that bromine intercalation does not alter the degradation of graphite-epoxy composites. No bromine was detected to have been released by the fibers allaying fears that outgassing could be disruptive to the sensitive electronics the EMI shield is meant to protect.

  17. Superconductivity in alkali metal intercalated iron selenides.

    PubMed

    Krzton-Maziopa, A; Svitlyk, V; Pomjakushina, E; Puzniak, R; Conder, K

    2016-07-27

    Alkali metal intercalated iron selenide superconductors A x Fe2-y Se2 (where A  =  K, Rb, Cs, Tl/K, and Tl/Rb) are characterized by several unique properties, which were not revealed in other superconducting materials. The compounds crystallize in overall simple layered structure with FeSe layers intercalated with alkali metal. The structure turned out to be pretty complex as the existing Fe-vacancies order below ~550 K, which further leads to an antiferromagnetic ordering with Néel temperature fairly above room temperature. At even lower temperatures a phase separation is observed. While one of these phases stays magnetic down to the lowest temperatures the second is becoming superconducting below ~30 K. All these effects give rise to complex relationships between the structure, magnetism and superconductivity. In particular the iron vacancy ordering, linked with a long-range magnetic order and a mesoscopic phase separation, is assumed to be an intrinsic property of the system. Since the discovery of superconductivity in those compounds in 2010 they were investigated very extensively. Results of the studies conducted using a variety of experimental techniques and performed during the last five years were published in hundreds of reports. The present paper reviews scientific work concerning methods of synthesis and crystal growth, structural and superconducting properties as well as pressure investigations. PMID:27248118

  18. Superconductivity in alkali metal intercalated iron selenides

    NASA Astrophysics Data System (ADS)

    Krzton-Maziopa, A.; Svitlyk, V.; Pomjakushina, E.; Puzniak, R.; Conder, K.

    2016-07-01

    Alkali metal intercalated iron selenide superconductors A x Fe2‑y Se2 (where A  =  K, Rb, Cs, Tl/K, and Tl/Rb) are characterized by several unique properties, which were not revealed in other superconducting materials. The compounds crystallize in overall simple layered structure with FeSe layers intercalated with alkali metal. The structure turned out to be pretty complex as the existing Fe-vacancies order below ~550 K, which further leads to an antiferromagnetic ordering with Néel temperature fairly above room temperature. At even lower temperatures a phase separation is observed. While one of these phases stays magnetic down to the lowest temperatures the second is becoming superconducting below ~30 K. All these effects give rise to complex relationships between the structure, magnetism and superconductivity. In particular the iron vacancy ordering, linked with a long-range magnetic order and a mesoscopic phase separation, is assumed to be an intrinsic property of the system. Since the discovery of superconductivity in those compounds in 2010 they were investigated very extensively. Results of the studies conducted using a variety of experimental techniques and performed during the last five years were published in hundreds of reports. The present paper reviews scientific work concerning methods of synthesis and crystal growth, structural and superconducting properties as well as pressure investigations.

  19. Superconductivity in intercalated molybdenum disulfide.

    NASA Technical Reports Server (NTRS)

    Somoano, R.; Hadek, V.; Rembaum, A.

    1972-01-01

    X-ray studies show the existence of two different types of expansions of the intercalated unit cell in both Na and K compounds. Two different phases are also indicated in the superconducting behavior of the K compound. All intercalated samples studied show a superconducting transition. K and Rb compounds become superconductors in the temperature range from 6.5 to 6.0 K. The Na compounds become superconductors at about 4.5 K. In all cases, the superconductivity disappears upon a short exposure of the sample to air. This phenomenon confirms that the superconductivity is due to the presence of the alkali metal.

  20. The Mechanics of Cell Intercalation

    NASA Astrophysics Data System (ADS)

    Mani, Madhav; Shraiman, Boris; Lecuit, Thomas

    2014-03-01

    Cell-intercalation involves the cytoskeleton-driven exchange of cellular neighbors. Developmental cues produce directional biases in the pattern of neighbor-exchanges, resulting in the alteration of tissue shape - morphogenesis. Focusing on cell-intercalation during early fly development, I will address both static and dynamical aspects. A quantitative correspondence is drawn between cytoskeletal levels, stresses and geometry. This construction of a constitutive law, relies on a novel image analysis tool that infers mechanical features of the cellular lattice from live imaging (from the Lecuit Lab, Marseilles). Building on our understanding of these static aspects, we construct a phenomenological, and physically-motivated, model for cytoskeletal remodeling based on temporal correlation analyses. This model predicts the qualitative phases of junctional states, insights into the T1 event that mediates intercalation, and several of the collective properties of cell-intercalation that have remained unaddressed so far - we go on to validate these predictions. We conclude with introducing the idea that tissue-wide anisotropies, central to morphogenesis and patterning in the embryo, can emerge as a consequences of the collective aspects of mechanical interactions.

  1. ASSESSMENT OF THE RELEVANCE OF DISPLACEMENT BASED DESIGN METHODS/CRITERIA TO NUCLEAR PLANT STRUCTURES.

    SciTech Connect

    HOFMAYER,C.; MILLER,C.; WANG,Y.; COSTELLO,J.

    2001-08-12

    Revisions to the USNRC Regulatory Guides and Standard Review Plan Sections devoted to earthquake engineering practice are currently in process. The intent is to reflect changes in engineering practice that have evolved in the twenty years that have passed since those criteria were originally published. Additionally, field observations of the effects of the Northridge (1994) and Kobe (1995) earthquakes have inspired some reassessment in the technical community about certain aspects of design practice. In particular, questions have arisen about the effectiveness of basing earthquake resistant designs on resistance to seismic forces and, then evaluating tolerability of the expected displacements. Therefore, a research effort was undertaken to examine the implications for NRC's seismic practice of the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The results of the NRC sponsored research on this subject are reported in this paper. A slow trend toward the utilization of displacement based methods for design was noted. However, there is a more rapid trend toward the use of displacement based methods for seismic evaluation of existing facilities. A document known as FEMA 273, has been developed and is being used as the basis for the design of modifications to enhance the seismic capability of existing non-nuclear facilities. The research concluded that displacement based methods, such as given in FEMA 273, may be useful for seismic margin studies of existing nuclear power stations. They are unlikely to be useful for the basic design of new stations since nuclear power stations are designed to remain elastic during a seismic event. They could, however, be useful for estimating the margins associated with that design.

  2. Intercalation of cyclic ketones into vanadyl phosphate

    SciTech Connect

    Zima, Vitezslav . E-mail: vitezslav.zima@upce.cz; Melanova, Klara; Benes, Ludvik; Trchova, Miroslava; Dybal, Jiri

    2005-01-15

    Intercalation compounds of vanadyl phosphate with cyclic ketones (cyclopentanone, cyclohexanone, 4-methylcyclohexanone, and 1,4-cyclohexanedione) were prepared from corresponding propanol or ethanol intercalates by a molecular exchange. The intercalates prepared were characterized using powder X-ray diffraction and thermogravimetric analysis. The intercalates are stable in dry environment and decompose slowly in humid air. Infrared and Raman spectra indicate that carbonyl oxygens of the guest molecules are coordinated to the vanadium atoms of the host layers. The local structure and interactions in the cyclopentanone intercalate have been suggested on the basis of quantum chemical calculations.

  3. Graphite fiber intercalation: Basic properties of copper chloride intercalated fibers

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Miller, J. D.

    1986-01-01

    In situ resistance measurements were used to follow the intercalation of copper chloride in pitch-based fibers. Subsequent single fiber resistivity measurements reveal a large range of resistivities, from 13 to 160 micro-ohms cm. Additional density measurements reveal a bimodal distribution of mass densities. The dense fibers have lower resistivities and correspond to the stage III compound identified by X-ray diffraction. Neither resistivity nor density correlate with diameter. Both energy dispersive spectroscopy and mass density data suggest that excess chlorine resides in the intercalated fiber, resulting in a stoichiometry of C4.9n CuCl2.5 (where n is the stage number) for the denser fibers. Finally, thermogravimetric analysis shows a 33 percent loss in mass upon heating to 700C. This loss in mass is attributed to loss of both chlorine and carbon.

  4. The mechanism of caesium intercalation of graphene

    NASA Astrophysics Data System (ADS)

    Petrović, M.; Šrut Rakić, I.; Runte, S.; Busse, C.; Sadowski, J. T.; Lazić, P.; Pletikosić, I.; Pan, Z.-H.; Milun, M.; Pervan, P.; Atodiresei, N.; Brako, R.; Šokčević, D.; Valla, T.; Michely, T.; Kralj, M.

    2013-11-01

    Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.

  5. The mechanism of caesium intercalation of graphene.

    PubMed

    Petrović, M; Šrut Rakić, I; Runte, S; Busse, C; Sadowski, J T; Lazić, P; Pletikosić, I; Pan, Z-H; Milun, M; Pervan, P; Atodiresei, N; Brako, R; Šokčević, D; Valla, T; Michely, T; Kralj, M

    2013-01-01

    Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials. PMID:24212475

  6. The alkaline earth intercalates of molybdenum disulfide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.; Samson, S.; Woollam, J. A.

    1975-01-01

    Molybdenum disulfide has been intercalated with calcium and strontium by means of the liquid ammonia technique. Chemical, X-ray, and superconductivity data are presented. The X-ray data reveal a lowering of crystal symmetry and increase of complexity of the structure upon intercalation with the alkaline earth metals. The Ca and Sr intercalates start to superconduct at 4 and 5.6 K, respectively, and show considerable anisotropy regarding the critical magnetic field.

  7. Alkali metal intercalates of molybdenum disulfide.

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.

    1973-01-01

    Study of some of the physicochemical properties of compounds obtained by subjecting natural molybdenite and single crystals of molybdenum disulfide grown by chemical vapor transport to intercalation with the alkali group of metals (Li, Na, K, Rb, and Cs) by means of the liquid ammonia technique. Reported data and results include: (1) the intercalation of the entire alkali metal group, (2) stoichiometries and X-ray data on all of the compounds, and (3) superconductivity data for all the intercalation compounds.

  8. Environmental stability of intercalated graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, J. R.; Jaworske, D. A.

    1985-01-01

    Graphite fibers intercalated with bromine, iodine monochloride, ferric chloride, and cupric chloride were subjected to stability tests under four environments which are encountered by engineering materials in the aerospace industry: ambient laboratory conditions, as would be experienced during handling operations and terrestrial applications; high vacuum, as would be experienced in space applications; high humidity, as would be experienced in marine applications; and high temperature, as would be experienced in some processing steps and applications. Monitoring the resistance of the fibers at ambient laboratory conditions revealed that only the ferric chloride intercalated fibers were unstable, due to absorption of water from the air. All four types of intercalated fibers were unstable, due to absorption of water from the air. All four types of intercalated fibers were stable for long periods under high vacuum. Ferric chloride, cupric chloride, and iodine monochloride intercalated fibers were sensitive to high humidity conditions. All intercalated fibers began to degrade above 250 C. The order of their thermal stability, from lowest to highest, was cupric chloride, iodine monochloride, bromine, and ferric chloride. Of the four types of intercalated fibers tested, the bromine intercalated fibers appear to have the most potential for application, based on environmental stability.

  9. Intercalation chemistry of zirconium 4-sulfophenylphosphonate

    SciTech Connect

    Svoboda, Jan; Zima, Vítězslav; Melánová, Klára; Beneš, Ludvík; Trchová, Miroslava

    2013-12-15

    Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4′-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules. - Graphical abstract: Nitrogen-containing organic compounds can be intercalated into the interlayer space of zirconium 4-sulfophenylphosphonate. - Highlights: • Zirconium 4-sulfophenylphosphonate was examined as a host material in intercalation chemistry. • A wide range of nitrogen-containing organic compounds were intercalated. • Possible arrangement of the intercalated species is described.

  10. Intercalation of lactones into vanadyl phosphate

    NASA Astrophysics Data System (ADS)

    Melánová, Klára; Beneš, Ludvík; Svoboda, Jan; Zima, Vítězslav

    2006-05-01

    Intercalates of vanadyl phosphate with α-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone, and ɛ-caprolactone were prepared by a displacement reaction of ethanol-intercalated VOPO4. As follows from the results of elemental analyses and thermogravimetry, intercalates contain about one molecule of the guest per formula unit. The diffractograms of the intercalates show a series of sharp (001) reflections, (200) reflection and some (hkl) lines with low intensity. The tetragonal lattice parameters of the intercalates were calculated. Both δ-valerolactone and ɛ-caprolactone intercalates are stable in air. The intercalates of lactones with side aliphatic chains are less stable. The CO stretching vibration in IR spectra of the intercalates prepared was shifted to lower wavenumbers in comparison with spectra of the pure guests, indicating that lactones are anchored to the host layers by their carbonyl oxygen. Analogously to the arrangement of γ-butyrolactone, also arrangement of molecules of other lactones in the interlayer space of the host layers was proposed.

  11. Triplex glue by synthesizing conjugated flexible intercalators.

    PubMed

    Pedersen, Erik B; Osman, Amany M A; Globisch, Daniel; Paramasivam, Manikandan; Cogoi, Susanna; Bomholt, Niels; Jørgensen, Per T; Xodo, Luigi E; Filichev, Vyacheslav V

    2008-01-01

    Bulge insertions of conjugated intercalators into the DNA triplex structure are found to give a dramatic contribution to the triplex stability. On the other hand insertions of conjugated intercalators are found to diminish quadruplex structures and in this way breaking down the self association of G-rich oligonucleotides under physiologically potassium ion conditions. A large number of intercalators are described here and they all result in dramatic increases of thermal stability of the corresponding triplexes. Another interesting aspect of conjugated intercalators is their use for assembling alternate strand triplexes. Targeting of neighbouring purine sequences on each their strand in the duplex DNA is a challenge for the 5'- 5' connectivity of the TFOs because of a large distance between the 5'-ends. The intercalator approach offers a linkage with the proper combination of flexibility and rigidity to produce alternate strand triplexes with higher stability than a similar wild type triplex of the same total length. PMID:18776241

  12. Displacement-based seismic design of flat slab-shear wall buildings

    NASA Astrophysics Data System (ADS)

    Sen, Subhajit; Singh, Yogendra

    2016-06-01

    Flat slab system is becoming widely popular for multistory buildings due to its several advantages. However, the performance of flat slab buildings under earthquake loading is unsatisfactory due to their vulnerability to punching shear failure. Several national design codes provide guidelines for designing flat slab system under gravity load only. Nevertheless, flat slab buildings are also being constructed in high seismicity regions. In this paper, performance of flat slab buildings of various heights, designed for gravity load alone according to code, is evaluated under earthquake loading as per ASCE/SEI 41 methodology. Continuity of slab bottom reinforcement through column cage improves the performance of flat slab buildings to some extent, but it is observed that these flat slab systems are not adequate in high seismicity areas and need additional primary lateral load resisting systems such as shear walls. A displacement-based method is proposed to proportion shear walls as primary lateral load resisting elements to ensure satisfactory performance. The methodology is validated using design examples of flat slab buildings with various heights.

  13. Displacement-Based Seismic Design Procedure for Framed Buildings with Dissipative Braces Part I: Theoretical formulation

    SciTech Connect

    Mazza, Fabio; Vulcano, Alfonso

    2008-07-08

    The insertion of steel braces equipped with dissipative devices proves to be very effective in order to enhance the performance of a framed building under horizontal seismic loads. Multi-level design criteria were proposed according to the Performance-Based Design, in order to get, for a specific level of the seismic intensity, a designated performance objective of the building (e.g., an assigned damage level of either the framed structure or non-structural elements). In this paper a design procedure aiming to proportion braces with hysteretic dampers in order to attain, for a specific level of the seismic intensity, a designated performance level of the building is proposed. Exactly, a proportional stiffness criterion, which assumes the elastic lateral storey-stiffness due to the braces proportional to that of the unbraced frame, is combined with the Direct Displacement-Based Design, in which the design starts from target deformations. A computer code has been prepared for the nonlinear static and dynamic analyses, using a step-by-step procedure. Frame members and hysteretic dampers are idealized by bilinear models.

  14. Displacement-Based Seismic Design Procedure for Framed Buildings with Dissipative Braces Part II: Numerical Results

    SciTech Connect

    Mazza, Fabio; Vulcano, Alfonso

    2008-07-08

    For a widespread application of dissipative braces to protect framed buildings against seismic loads, practical and reliable design procedures are needed. In this paper a design procedure based on the Direct Displacement-Based Design approach is adopted, assuming the elastic lateral storey-stiffness of the damped braces proportional to that of the unbraced frame. To check the effectiveness of the design procedure, presented in an associate paper, a six-storey reinforced concrete plane frame, representative of a medium-rise symmetric framed building, is considered as primary test structure; this structure, designed in a medium-risk region, is supposed to be retrofitted as in a high-risk region, by insertion of diagonal braces equipped with hysteretic dampers. A numerical investigation is carried out to study the nonlinear static and dynamic responses of the primary and the damped braced test structures, using step-by-step procedures described in the associate paper mentioned above; the behaviour of frame members and hysteretic dampers is idealized by bilinear models. Real and artificial accelerograms, matching EC8 response spectrum for a medium soil class, are considered for dynamic analyses.

  15. A complete solution of cartographic displacement based on elastic beams model and Delaunay triangulation

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Guo, Q.; Sun, Y.

    2014-04-01

    In map production and generalization, it is inevitable to arise some spatial conflicts, but the detection and resolution of these spatial conflicts still requires manual operation. It is become a bottleneck hindering the development of automated cartographic generalization. Displacement is the most useful contextual operator that is often used for resolving the conflicts arising between two or more map objects. Automated generalization researches have reported many approaches of displacement including sequential approaches and optimization approaches. As an excellent optimization approach on the basis of energy minimization principles, elastic beams model has been used in resolving displacement problem of roads and buildings for several times. However, to realize a complete displacement solution, techniques of conflict detection and spatial context analysis should be also take into consideration. So we proposed a complete solution of displacement based on the combined use of elastic beams model and constrained Delaunay triangulation (CDT) in this paper. The solution designed as a cyclic and iterative process containing two phases: detection phase and displacement phase. In detection phase, CDT of map is use to detect proximity conflicts, identify spatial relationships and structures, and construct auxiliary structure, so as to support the displacement phase on the basis of elastic beams. In addition, for the improvements of displacement algorithm, a method for adaptive parameters setting and a new iterative strategy are put forward. Finally, we implemented our solution on a testing map generalization platform, and successfully tested it against 2 hand-generated test datasets of roads and buildings respectively.

  16. Graphite intercalation compound with iodine as the major intercalate

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh; Kucera, Donald

    1994-01-01

    Halogenated graphite CBr(x)I(y) (I less than y/x less than 10) was made by exposing graphite materials to either pure Br2 or an I2/Br2/HBr mixture to initiate the reaction, and then to iodine vapor containing a small amount of Br2/HBr/IBr to complete the intercalation reaction. Wetting of the graphite materials by the I2/Br2/HBr mixture is needed to start the reaction, and a small amount of Br2/HBr/IBr is needed to complete the charge transfer between iodine and carbon. The interplanar spacings for the graphite materials need to be in the 3.35 to 3.41 A range. The X-ray diffraction data obtained from the halogenated HOPG indicate that the distance between the two carbon layers containing intercalate is 7.25 A. Electrical resistivity of the fiber product is from 3 to 6.5 times the pristine value, The presence of a small amount of isoprene rubber in the reaction significantly increased the iodine-to-bromine ratio in the product. In this reaction, rubber is known to generate HBr and to slowly remove bromine from the vapor. The halogenation generally caused a 22 percent to 25 percent weight increase. The halogens were found uniformly distributed in the product interior. However, although the surface contains very little iodine, it has high concentrations of bromine and oxygen. It is believed that the high concentrations of bromine and oxygen in this surface cause the halogenated fiber to be more resistant to structural damage during subsequent fluorination to fabricate graphite fluoride fibers.

  17. Electrochemical Li-Ion Intercalation in Octacyanotungstate-Bridged Coordination Polymer with Evidence of Three Magnetic Regimes.

    PubMed

    Long, Jérôme; Asakura, Daisuke; Okubo, Masashi; Yamada, Atsuo; Guari, Yannick; Larionova, Joulia

    2016-08-01

    Discovery of novel compounds capable of electrochemical ion intercalation is a primary step toward development of advanced electrochemical devices such as batteries. Although cyano-bridged coordination polymers including Prussian blue analogues have been intensively investigated as ion intercalation materials, the solid-state electrochemistry of the octacyanotungstate-bridged coordination polymer has not been investigated. Here, we demonstrate that an octacyanotungstate-bridged coordination polymer Tb(H2O)5[W(CN)8] operates as a Li(+)-ion intercalation electrode material. The detailed magnetic measurements reveal that the tunable amount of intercalated Li(+) ion in the solid-state redox reaction between paramagnetic [W(V)(CN)8](3-) and diamagnetic [W(IV)(CN)8](4-) in the framework enables the electrochemical control of different magnetic regimes. While the initial ferromagnetic long-range ordering is irreversibly lost upon lithium insertion, electrochemical switching between paramagnetic and short-range ordering regimes can be achieved. PMID:27420412

  18. Intercalated hybrid graphite fiber composite

    NASA Technical Reports Server (NTRS)

    Gaier, James R. (Inventor)

    1993-01-01

    The invention is directed to a highly conductive lightweight hybrid material and methods of producing the same. The hybrid composite is obtained by weaving strands of a high strength carbon or graphite fiber into a fabric-like structure, depositing a layer of carbon onto the structure, heat treating the structure to graphitize the carbon layer, and intercalating the graphitic carbon layer structure. A laminate composite material useful for protection against lightning strikes comprises at least one layer of the hybrid material over at least one layer of high strength carbon or graphite fibers. The composite material of the present invention is compatible with matrix compounds, has a coefficient of thermal expansion which is the same as underlying fiber layers, and is resistant to galvanic corrosion in addition to being highly conductive. These materials are useful in the aerospace industry, in particular as lightning strike protection for airplanes.

  19. Stability of Bromine Intercalated Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Gaier, J. R.

    1984-01-01

    Previous evidence suggested that bromine intercalation compounds of crystalline graphite spontaneously deintercalate when the bromine atmosphere is removed. However, results show that bromine intercalated P-100 graphite fibers are stable for long periods of time. They are stable under vacuum conditions, high humidity, and current densities up to 24,000 A/sq cm. They are thermally stable to 200 C, and at temperatures as high as 400 C still retain 80 percent of the conductivity gained by intercalation. At temperatures greater than 300 C, there is significant oxidative degradation of the fibers. The environmental stability shown by the bromine compound makes it a promising candidate for practical applications in aerospace technology.

  20. The intercalated cells of the amygdala.

    PubMed

    Millhouse, O E

    1986-05-01

    The intercalated cell groups, or massa intercalata, of the amygdala have been studied in rodent brains with Golgi methods. They also have been examined in gallocyanin-chromalum-, AChE-, and Timm-stained rat brains. The Golgi data indicate that the intercalated cells are not confined to a series of isolated cell clumps but form a neuronal net that covers the rostral half of the lateral-basolateral nuclear complex, stretches across a major portion of rostral amygdala, and continues rostrally beneath the anterior commissure. There are two general types of intercalated neuron--medium and large neurons. The medium intercalated neurons are more common. They have round to elongate somata, 9-18 microns in diameter, and round to bipolar dendritic trees, depending on their location. Most of the dendrites are spine-bearing, as are 20% of the somata. Their axons often have locally ramifying collaterals. The parent axons apparently terminate in either the lateral-basolateral or central nuclei and some of them appear to enter the external capsule. There is a unique medium intercalated neuron that has nearly spine-free, varicose dendrites and an axon that is typical of short axon (Golgi II) cells. There are two varieties of large intercalated neuron-spiny and aspiny. Most of them are aspiny, although they usually have a few spines scattered along their dendrites. Both varieties have elongate, sometimes round, somata that can be as much as 60 microns long. Their dendrites are long, thick, and have few branch points. Only the initial part of the large aspiny cell axon has been impregnated. The large spiny cell axons have several local collaterals; the destination of the parent axons is unknown. The intercalated cells occur along fiber bundles, which are probably afferent to them. The axons that travel among the intercalated cells give off short collaterals and boutons en passant. The sources of these fibers are not known. From the published experimental data, it is likely that they

  1. Effect of water intercalation on VOx layers in dodecylamine-intercalated vanadium oxide nanotubes

    NASA Astrophysics Data System (ADS)

    Kweon, Hyocheon; Lee, Kyu Won; Lee, Eun Mo; Park, Jitae; Kim, I.-M.; Lee, Cheol Eui; Jung, G.; Gedanken, A.; Koltypin, Yu.

    2007-07-01

    Dodecylamine-intercalated vanadium oxide nanotubes were obtained by distinct synthesis processes. Water intercalation in the nanotube structure was identified in a marked manner by the distortion of the VOx layers in the x-ray diffraction patterns and enhanced V4+O absorption in the Fourier-transform infrared spectra. Our electron spin resonance measurements sensitively reflect changes in the microscopic structure and magnetic interactions introduced by the water intercalation in the vanadium oxide nanotubes.

  2. A method to remove intercalates from bromine and iodine intercalated carbon fibers

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    1993-01-01

    Upon exposure to room-temperature fluorine, intercalated carbon fibers (containing either bromine alone or iodine and bromine together) become heavier and less stable. For Amoco P-100 graphitized carbon fibers which were intercalated with 18 percent bromine by weight, 1 hr of fluorine exposure results in a large weight increase, but causes only a small decrease in thermal stability. More than l hr of fluorine exposure time results in small additional increases in fiber weight, but significant further decreases in fiber thermal stability. Such phenomena do not occur if the fluorine exposure is at 250 C. These observations suggest the mechanism that at room temperature, fluorine is absorbed quickly by the intercalated fibers and intercalated slowly into the fibers. Most of the original intercalates are replaced by fluorine in the process of fluorine intercalation. Under an inert environment, the bromine intercalated fibers are much more thermally stable. After 800 C vacuum heating for two weeks, the brominated fibers lost about 45 percent of their bromine, and their resistivity increased from 64 omega-cm to a range of 95 to 170 micro omega-cm. This is still much lower than the 300 micro omega-cm value for pristine P-100. For practical purposes, in order to preserve their thermal stability, brominated fibers need to be protected from exposure to fluorine at room temperature, or to any intercalate at a temperature where, upon direct contact to graphite, an intercalation compound can easily be formed.

  3. Collecting duct intercalated cell function and regulation.

    PubMed

    Roy, Ankita; Al-bataineh, Mohammad M; Pastor-Soler, Núria M

    2015-02-01

    Intercalated cells are kidney tubule epithelial cells with important roles in the regulation of acid-base homeostasis. However, in recent years the understanding of the function of the intercalated cell has become greatly enhanced and has shaped a new model for how the distal segments of the kidney tubule integrate salt and water reabsorption, potassium homeostasis, and acid-base status. These cells appear in the late distal convoluted tubule or in the connecting segment, depending on the species. They are most abundant in the collecting duct, where they can be detected all the way from the cortex to the initial part of the inner medulla. Intercalated cells are interspersed among the more numerous segment-specific principal cells. There are three types of intercalated cells, each having distinct structures and expressing different ensembles of transport proteins that translate into very different functions in the processing of the urine. This review includes recent findings on how intercalated cells regulate their intracellular milieu and contribute to acid-base regulation and sodium, chloride, and potassium homeostasis, thus highlighting their potential role as targets for the treatment of hypertension. Their novel regulation by paracrine signals in the collecting duct is also discussed. Finally, this article addresses their role as part of the innate immune system of the kidney tubule. PMID:25632105

  4. Hydrogen intercalation under graphene on Ir(111)

    NASA Astrophysics Data System (ADS)

    Grånäs, Elin; Gerber, Timm; Schröder, Ulrike A.; Schulte, Karina; Andersen, Jesper N.; Michely, Thomas; Knudsen, Jan

    2016-09-01

    Using high resolution X-ray photoelectron spectroscopy and scanning tunneling microscopy we study the intercalation of hydrogen under graphene/Ir(111). The hydrogen intercalated graphene is characterized by a component in C 1s that is shifted -0.10 to -0.18 eV with respect to pristine graphene and a component in Ir 4f at 60.54 eV. The position of this Ir 4f component is identical to that of the Ir(111) surface layer with hydrogen atoms adsorbed, indicating that the atomic hydrogen adsorption site on bare Ir(111) and beneath graphene is the same. Based on co-existence of fully- and non-intercalated graphene, and the inability to intercalate a closed graphene film covering the entire Ir(111) surface, we conclude that hydrogen dissociatively adsorbs at bare Ir(111) patches, and subsequently diffuses rapidly under graphene. A likely entry point for the intercalating hydrogen atoms is identified to be where graphene crosses an underlying Ir(111) step.

  5. Organic intercalation of structure modified vermiculite.

    PubMed

    Wu, Nian; Wu, Limei; Liao, Libing; Lv, Guocheng

    2015-11-01

    The experiment used cationic surfactants of different chain lengths to intercalate structure modified vermiculites. The influences of structure modification, chain length and dosage of surfactants on the intercalation behavior of vermiculites were studied, and intercalation mechanism and features of interlayer chemical reactions were discussed. Results indicate that structure modified vermiculites with different layer charge have different intercalation behavior. The basal spacing of the organic intercalated modified vermiculite is the largest when acid concentration used in structure modification is 0.003 mol/L, and increases with increasing the chain length and dosage of the organics. Molecular dynamics simulation verifies that interlayer organics align almost parallel to structure layer of vermiculite, with alkyl chain stretching to the middle of interlayer space. -N(+) groups of the three surfactants locate above the leached [SiO4], which has stronger interaction with interlayer organic cations. Electrostatic force is the main interaction force between interlayer organics and structure layer of vermiculite, and then is Van der Waals force, no chemical bond formed. PMID:26196709

  6. Feasibility of intercalated graphite railgun armatures

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steven

    1990-01-01

    Graphite intercalation compounds may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have the desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations were performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading are addressed for the case of highly oriented pyrolytic graphite.

  7. Intercalation of Aldehydes into Vanadyl Phosphate

    NASA Astrophysics Data System (ADS)

    Melánová, Klára; Beneš, Ludvík.; Zima, Vítězslav; Votinský, Jiří

    2001-02-01

    Intercalates of VOPO4 with several aliphatic aldehydes, benzaldehyde, and 4-methylbenzaldehyde were prepared and characterized by thermogravimetric analysis, X-ray diffractometry, and IR and UV-vis spectroscopies. Aliphatic aldehyde intercalates are unstable and the guests undergo aldol condensation and oxidation. The arrangement of the guest molecules in the interlayer space of the host is discussed. A part of aliphatic aldehydes is anchored to the host layers by coordination of their carbonyl oxygen to the vanadium atom; the rest is probably bonded by weak van der Waals forces. In the benzaldehyde and 4-methylbenzaldehyde intercalates, all guest molecules are coordinated to the vanadium atoms with their benzene rings perpendicular to the sheets of the host.

  8. Demonstration of Einstein-Podolsky-Rosen Steering Using Single-Photon Path Entanglement and Displacement-Based Detection.

    PubMed

    Guerreiro, T; Monteiro, F; Martin, A; Brask, J B; Vértesi, T; Korzh, B; Caloz, M; Bussières, F; Verma, V B; Lita, A E; Mirin, R P; Nam, S W; Marsilli, F; Shaw, M D; Gisin, N; Brunner, N; Zbinden, H; Thew, R T

    2016-08-12

    We demonstrate the violation of an Einstein-Podolsky-Rosen steering inequality developed for single-photon path entanglement with displacement-based detection. We use a high-rate source of heralded single-photon path-entangled states, combined with high-efficiency superconducting-based detectors, in a scheme that is free of any postselection and thus immune to the detection loophole. This result conclusively demonstrates single-photon entanglement in a one-sided device-independent scenario, and opens the way towards implementations of device-independent quantum technologies within the paradigm of path entanglement. PMID:27563941

  9. Demonstration of Einstein-Podolsky-Rosen Steering Using Single-Photon Path Entanglement and Displacement-Based Detection

    NASA Astrophysics Data System (ADS)

    Guerreiro, T.; Monteiro, F.; Martin, A.; Brask, J. B.; Vértesi, T.; Korzh, B.; Caloz, M.; Bussières, F.; Verma, V. B.; Lita, A. E.; Mirin, R. P.; Nam, S. W.; Marsilli, F.; Shaw, M. D.; Gisin, N.; Brunner, N.; Zbinden, H.; Thew, R. T.

    2016-08-01

    We demonstrate the violation of an Einstein-Podolsky-Rosen steering inequality developed for single-photon path entanglement with displacement-based detection. We use a high-rate source of heralded single-photon path-entangled states, combined with high-efficiency superconducting-based detectors, in a scheme that is free of any postselection and thus immune to the detection loophole. This result conclusively demonstrates single-photon entanglement in a one-sided device-independent scenario, and opens the way towards implementations of device-independent quantum technologies within the paradigm of path entanglement.

  10. Metal Ion Intercalated graphitic as Transparent Electrodes

    NASA Astrophysics Data System (ADS)

    Wan, Jiayu; Bao, Wenzhong; Gu, Feng; Fuhrer, Michael; Hu, Liangbing; UMD Team

    To best utilize the performance of graphene based transparent electrodes, we novelized Li-ion intercalation in graphene, and achieved highest performance of carbon based transparent electrodes. Transmission as high as 91.7% with a sheet resistance of 3.0 ohm/sq is achieved for 19-layer LiC6, significantly higher than any other continuous transparent electrodes. The unconventional modification of ultrathin graphite optoelectronic properties is explained by the suppression of interband optical transitions and a small intraband Drude conductivity near the interband edge. To achieve low cost, large scale graphene-based transparent electrodes, we further developed Na-ion intercalated printed reduced graphene oxide (RGO) film. The larger layer-layer distance of RGO allows Na-ion intercalation, leading to simultaneously much higher DC conductivity and higher optical transmittance. Typical increase of transmittance from 36% to 79% and decrease of sheet resistance from 83 kohms/sq to 311 ohms/sq in the printed network was observed. This study demonstrated the great potential of metal-ion intercalation to improve the performance of graphene-based materials for transparent conductor applications.

  11. Mg intercalation into Ti2C building block

    NASA Astrophysics Data System (ADS)

    Yu, Xue-fang; Cheng, Jianbo; Liu, Zhenbo; Li, Qingzhong; Li, Wenzuo; Yang, Xin; Xiao, Bo

    2015-06-01

    Generally, intercalation occurs when foreign atoms intercalate into multi-layer structures, while adsorption occurs when foreign atoms interact with monolayer structures or surfaces. We performed an investigation on the Mg intercalation into Ti2C building block (MXene) from first-principles simulation. We found that Mg can favorably intercalate into MXene, forming the stable compound Ti2MgC, which corresponds to the stage I in the Li intercalation into graphite. Based on the evaluation of the average cell potential and the energy barrier of Mg diffusion for the most energetically stable structure, our results suggest that Ti2MgC is a potential anode for Mg ion batteries.

  12. Hexacyanoferrate-intercalated nickel zinc hydroxy double salts

    NASA Astrophysics Data System (ADS)

    Rajamathi, Jacqueline T.; Raviraj, N. H.; Ahmed, Mohammed F.; Rajamathi, Michael

    2009-12-01

    When anionic clay like nickel zinc hydroxyacetate was subjected to anion exchange reaction with either hexacyanoferrate(II) or hexacyanoferrate(III) ions, the complex anion intercalation was accompanied by auto redox reactions. In both the cases a mixture of hexacyanoferrate(II) and hexacyanoferrate(III) ions was found to be intercalated in the anionic clay. The mixed anion intercalated anionic clays could be oxidized by hydrogen peroxide to get pure hexacyanoferrate(III) intercalated anionic clay. Thermal decomposition of the intercalated anionic clays yields mixed oxides of Ni, Zn and Fe.

  13. Assessment of Soil-Structure Interaction in Seismic Bridge Pier Analysis Using Force and Displacement Based Approaches

    NASA Astrophysics Data System (ADS)

    Singh, R. N. P.; Vinayak, Hemant Kumar

    2015-11-01

    The seismic analysis carried out assuming foundation to be perfectly rigid and bonded to the soil underneath is far from truth and therefore, the soil-structure interaction effect on the dynamic behavior of the bridge pier should be considered. The assessment of soil-structure effect on the design force generated has been estimated using Force based, Capacity Spectrum and Direct Displacement based methods considering fixed and flexible foundations. For this purpose a single cantilever bridge pier of constant diameter with varying heights has been considered for the analysis in different type of soils and earthquake zones. The study has revealed that soil-Structure Interaction index is negative in some cases, especially in soft soil, implying base shear demand being greater than that of fixed base contrary to the traditional views.

  14. Phosphate-stabilized Lithium intercalation compounds

    SciTech Connect

    Richardson, Thomas J.

    2002-07-22

    Four manganese and iron phosphates with alluaudite or fillowite structures have been prepared by solid state reactions: Na2FeMn2(PO4)3, LiNaFeMn2(PO4)3, NaFe3(PO4)3, and Na2Mn3(PO4)3. LixNa2-xFeMn2(PO4)3 with x close to 2 was prepared from Na2FeMn2(PO4)3 by molten salt ion exchange. These materials are similar in stoichiometry to the phospho-olivines LiFe(Mn)PO4, but have a more complex structure that can accommodate mixed transition metal oxidation states. They are of interest as candidates for lithium battery cathodes because of their somewhat higher electronic conductivity, high intercalant ion mobility, and ease of preparation. Their performance as intercalation electrodes in non-aqueous lithium cells was, however, poor.

  15. Discovery Systems

    NASA Technical Reports Server (NTRS)

    Pell, Barney

    2003-01-01

    A viewgraph presentation on NASA's Discovery Systems Project is given. The topics of discussion include: 1) NASA's Computing Information and Communications Technology Program; 2) Discovery Systems Program; and 3) Ideas for Information Integration Using the Web.

  16. Guided Discoveries.

    ERIC Educational Resources Information Center

    Ehrlich, Amos

    1991-01-01

    Presented are four mathematical discoveries made by students on an arithmetical function using the Fibonacci sequence. Discussed is the nature of the role of the teacher in directing the students' discovery activities. (KR)

  17. Monte Carlo simulation of intercalated carbon nanotubes.

    PubMed

    Mykhailenko, Oleksiy; Matsui, Denis; Prylutskyy, Yuriy; Le Normand, Francois; Eklund, Peter; Scharff, Peter

    2007-01-01

    Monte Carlo simulations of the single- and double-walled carbon nanotubes (CNT) intercalated with different metals have been carried out. The interrelation between the length of a CNT, the number and type of metal atoms has also been established. This research is aimed at studying intercalated systems based on CNTs and d-metals such as Fe and Co. Factors influencing the stability of these composites have been determined theoretically by the Monte Carlo method with the Tersoff potential. The modeling of CNTs intercalated with metals by the Monte Carlo method has proved that there is a correlation between the length of a CNT and the number of endo-atoms of specific type. Thus, in the case of a metallic CNT (9,0) with length 17 bands (3.60 nm), in contrast to Co atoms, Fe atoms are extruded out of the CNT if the number of atoms in the CNT is not less than eight. Thus, this paper shows that a CNT of a certain size can be intercalated with no more than eight Fe atoms. The systems investigated are stabilized by coordination of 3d-atoms close to the CNT wall with a radius-vector of (0.18-0.20) nm. Another characteristic feature is that, within the temperature range of (400-700) K, small systems exhibit ground-state stabilization which is not characteristic of the higher ones. The behavior of Fe and Co endo-atoms between the walls of a double-walled carbon nanotube (DW CNT) is explained by a dominating van der Waals interaction between the Co atoms themselves, which is not true for the Fe atoms. PMID:17033783

  18. Superconducting graphite intercalation compounds with calcium

    NASA Astrophysics Data System (ADS)

    Emery, N.; Hérold, C.; Marêché, J.-F.; Lagrange, P.; Bellouard, C.; Lamura, G.; Di Gennaro, E.; Andreone, A.

    2008-04-01

    In the graphite-lithium-calcium system, four well-defined intercalation compounds were synthesised. Two of them, CaC 6 and Li 3Ca 2C 6, exhibit superconducting properties at 11.5 K and 11.15 K, respectively, the highest critical temperatures among those of graphite intercalation compounds. The samples are synthesised using a liquid-solid method allowing the preparation of pure bulk samples, auspicious for crystallographic and magnetic measurements. The crystal structure of CaC 6 was entirely specified; this compound crystallises in the R-3 m space group. The two-dimensional unit cell of Li 3Ca 2C 6 is hexagonal and commensurate with that of graphite and the intercalated sheets, very rich in metal, are seven-layered. The magnetic properties of these phases were studied with an applied field parallel and perpendicular to the graphene sheets. In both cases the magnetic phase diagram indicates that these compounds are type II superconducting materials slightly anisotropic in spite of their lamellar structure. In the case of CaC 6, in-plane magnetic penetration depth measurements show a clear exponential behaviour at low temperatures, consistent with an s-wave symmetry of the gap function, well fitted by the standard BCS theory in the dirty limit.

  19. EMI Shields made from intercalated graphite composites

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Terry, Jennifer

    1995-01-01

    Electromagnetic interference (EMI) shielding typically makes up about twenty percent of the mass of a spacecraft power system. Graphite fiber/polymer composites have significantly lower densities and higher strengths than aluminum, the present material of choice for EMI shields, but they lack the electrical conductivity that enables acceptable shielding effectiveness. Bromine intercalated pitch-based graphite/epoxy composites have conductivities fifty times higher than conventional structural graphite fibers. Calculations are presented which indicate that EMI shields made from such composites can have sufficient shielding at less than 20% of the mass of conventional aluminum shields. EMI shields provide many functions other than EMI shielding including physical protection, thermal management, and shielding from ionizing radiation. Intercalated graphite composites perform well in these areas also. Mechanically, they have much higher specific strength and modulus than aluminum. They also have shorter half thicknesses for x-rays and gamma radiation than aluminum. Thermally, they distribute infra-red radiation by absorbing and re-radiating it rather than concentrating it by reflection as aluminum does. The prospects for intercalated graphite fiber/polymer composites for EMI shielding are encouraging.

  20. Pristine and intercalated transition metal dichalcogenide superconductors

    NASA Astrophysics Data System (ADS)

    Klemm, Richard A.

    2015-07-01

    Transition metal dichalcogenides (TMDs) are quasi-two-dimensional layered compounds that exhibit strongly competing effects of charge-density wave (CDW) formation and superconductivity (SC). The weak van der Waals interlayer bonding between hexagonal layers of octahedral or trigonal prismatic TMD building blocks allows many polytypes to form. In the single layer 1 T polytype materials, one or more CDW states can form, but the pristine TMDs are not superconducting. The 2 H polytypes have two or more Fermi surfaces and saddle bands, allowing for dual orderings, which can be coexisting CDW and SC orderings, two SC gaps as in MgB2, two CDW gaps, and possibly even pseudogaps above the onset TCDW s of CDW orderings. Higher order polytypes allow for multiple CDW gaps and at least one superconducting gap. The CDW transitions TCDW s usually greatly exceed the superconducting transitions at their low Tc values, their orbital order parameters (OPs) are generally highly anisotropic and can even contain nodes, and the SC OPs can be greatly affected by their simultaneous presence. The properties of the CDWs ubiquitously seen in TMDs are remarkably similar to those of the pseudogaps seen in the high-Tc cuprates. In 2H-NbSe2, for example, the CDW renders its general s-wave SC OP orbital symmetry to be highly anisotropic and strongly reduces its Josephson coupling strength (IcRn) with the conventional SC, Pb. Hence, the pristine TMDs are highly "unconventional" in comparison with Pb, but are much more "conventional" than are the ferromagnetic superconductors such as URhGe. Applied pressure and intercalation generally suppress the TMD CDWs, allowing for enhanced SC formation, even in the 1 T polytype materials. The misfit intercalation compound (LaSe)1.14(NbSe2) and many 2 H -TMDs intercalated with organic Lewis base molecules, such as TaS2(pyridine)1/2, have completely incoherent c-axis transport, dimensional-crossover effects, and behave as stacks of intrinsic Josephson junctions

  1. Intercalation compounds and electrodes for batteries

    DOEpatents

    Chiang, Yet-Ming; Sadoway, Donald R.; Jang, Young-Il; Huang, Biyan

    2004-09-07

    This invention concerns intercalation compounds and in particular lithium intercalation compounds which have improved properties for use in batteries. Compositions of the invention include particulate metal oxide material having particles of multicomponent metal oxide, each including an oxide core of at least first and second metals in a first ratio, and each including a surface coating of metal oxide or hydroxide that does not include the first and second metals in the first ratio formed by segregation of at least one of the first and second metals from the core. The core may preferably comprise Li.sub.x M.sub.y N.sub.z O.sub.2 wherein M and N are metal atom or main group elements, x, y and z are numbers from about 0 to about 1 and y and z are such that a formal charge on M.sub.y N.sub.z portion of the compound is (4-x), and having a charging voltage of at least about 2.5V. The invention may also be characterized as a multicomponent oxide microstructure usable as a lithium intercalation material including a multiphase oxide core and a surface layer of one material, which is a component of the multiphase oxide core, that protects the underlying intercalation material from chemical dissolution or reaction. In a particular preferred example the multicomponent oxide may be an aluminum-doped lithium manganese oxide composition. Such aluminum-doped lithium manganese oxide compositions, having an orthorhombic structure, also form a part of the invention. In addition, the invention includes articles, particularly electrodes, for batteries formed from the compositions of the invention, and batteries including such electrodes. The invention further relates to a composite intercalation material comprising at least two compounds in which at least one compound has an orthorhombic structure Li.sub.x Al.sub.y Mn.sub.1-y O.sub.2, where y is nonzero, or a mixture of orthorhombic and monoclinic Li.sub.x Al.sub.y Mn.sub.1-y O.sub.2.

  2. Synthesis and stability of Br2, ICl and IBr intercalated pitch-based graphite fibers

    NASA Technical Reports Server (NTRS)

    Wessbecher, Dorothy E.; Forsman, William C.; Gaier, James R.

    1988-01-01

    The intercalation of halogens in pitch-based fiber is studied as well as the stability of the resultant intercalation compounds. It is found that IBr intercalates P-100 to yield a high-sigma GIC with attractive stability properties. During ICl intercalation, the presence of O2 interferes with the reaction and necessitates a higher threshold pressure for intercalation.

  3. Physics and chemistry of MoS2 intercalation compounds

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Somoano, R. B.

    1977-01-01

    An investigation is made of the physics and chemistry of MoS2 intercalation compounds. These compounds may be separated into two groups according to their stoichiometry, structure and superconducting properties. The first group consists of Na, Ca, and Sr intercalates, and the second group consists of K, Rb, and Cs intercalates. Particular attention is given to the structure of the electronic energy band and to the normal state and superconducting properties of these compounds.

  4. Tuning frictions between graphene layers via Li ion intercalation

    NASA Astrophysics Data System (ADS)

    Lu, Aijiang; Wan, Jiayu; Li, Teng; Hu, Liangbing; Univerisyt of Maryland, College Park Team

    Graphite intercalated with Li ions are widely studied and applied in Li ion batteries. It was revealed in experiments that, the Li ion intercalation leads to a phase transition of the graphite with about 10% volume expansion. The increased interlayer distance should contribute to decrease the frictions between the grahene layers, but the Li ion intercalation would take an opposite effect. In order to show the total effect of the Li ion interalation, we studied the frictions between graphene layers with and without lithiation, based on density functional theory (DFT). In a sandwich-like model, slipping of the middle sheet of the graphene was simulated. Displacements between layers were fixed and the other parts were relaxed, thus the energies were record to estimate the energy barriers accordingly. We found that the frictions between the graphene layers with the Li ion intercalation are higher than those without intercalation. The energy barrier appears correlated with the concentration of the intercalated ions. As the atomic ratio between lithium and carbon increases from 0 (no intercalation) to 1:6, the energy barriers increase from 0.01 eV/atom to 0.05 eV/atom or so. Such an interesting result indicates that, just via ion intercalation, we can effectively tune the friction between graphene layers. Tuning frictions between graphene layers via Li ion intercalation.

  5. Intercalation of Anionic Oxalato Complexes into Layered Double Hydroxides

    NASA Astrophysics Data System (ADS)

    Prevot, V.; Forano, C.; Besse, J. P.

    2000-09-01

    Intercalation compounds of layered double hydroxide (LDH), MII1-xMIIIx(OH)2Ax/y·nH2O (with MII=Zn, Cu and MIII=Al, Cr, Ga), with oxalato complexes of aluminium, gallium, chromium, copper, and beryllium, were obtained via anion-exchange processes. Powder X-ray diffraction indicated that the intercalation reactions were successful. The basal spacings measured after intercalation are near 0.98±0.02 nm, whatever the host matrix composition. Studies by FTIR spectroscopy confirmed the intercalation of the oxalato complex, too. In order to study the thermal decomposition of the exchanged products, TGA-coupled mass spectrometry was performed.

  6. Superconductivity in Li{sub 3}Ca{sub 2}C{sub 6} intercalated graphite

    SciTech Connect

    Emery, Nicolas; Herold, Claire . E-mail: Claire.Herold@lcsm.uhp-nancy.fr; Mareche, Jean-Francois; Bellouard, Christine; Loupias, Genevieve; Lagrange, Philippe

    2006-04-15

    In this paper, we report the discovery of superconductivity in Li{sub 3}Ca{sub 2}C{sub 6}. Several graphite intercalation compounds (GICs) with electron donors, are well known as superconductors [T. Enoki, S. Masatsugu, E. Morinobu, Graphite Intercalation Compounds and Applications, Oxford University Press, Oxford, 2003]. It is probably not astonishing, since it is generally admitted that low dimensionality promotes high superconducting transition temperatures. Superconductivity is lacking in pristine graphite, but after charging the graphene planes by intercalation, its electronic properties change considerably and superconducting behaviour can appear. Li{sub 3}Ca{sub 2}C{sub 6} is a ternary GIC [S. Pruvost, C. Herold, A. Herold, P. Lagrange, Eur. J. Inorg. Chem. 8 (2004) 1661-1667], for which the intercalated sheets are very thick and poly layered (five lithium layers and two calcium ones). It contains a great amount of metal (five metallic atoms for six carbon ones). Its critical temperature of 11.15 K is very close to that of CaC{sub 6} GIC [T.E. Weller, M. Ellerby, S.S. Saxena, R.P. Smith, N.T. Skipper, Nat. Phys. 1 (2005) 39-41; N. Emery, C. Herold, M. d'Astuto, V. Garcia, Ch. Bellin, J.F. Mareche, P. Lagrange, G. Loupias, Phys. Rev. Lett. 95 (2005) 087003] (11.5 K). Both CaC{sub 6} and Li{sub 3}Ca{sub 2}C{sub 6} GICs possess currently the highest transition temperatures among all the GICs.

  7. Intercalation of water into lithium. beta. -alumina

    SciTech Connect

    Dudney, N J; Bates, J B; Wang, J C; Brown, G M; Larson, B C; Engstrom, H

    1981-01-01

    Infrared absorption, neutron diffraction and weight loss techniques have been used to investigate the hydration of single crystals of Li ..beta..-alumina. The hydration is a reversible intercalation reaction. Up to approximately two water molecules per formula unit can penetrate the conduction plane. Other protonated species are formed from the dissociation of the molecular water. The rate of hydration is controlled by the diffusion of water in the conduction plane. A likely diffusion mechanism requires dissociation of the water and an interstitialcy motion of the oxygen.

  8. Lithium intercalation in porous carbon anodes

    SciTech Connect

    Tran, T.D.; Pekala, R.W.; Mayer, S.T.

    1994-11-23

    Carbon foams derived from the phase separation of polyacrylonitrile/solvent mixtures were investigated as lithium intercalation anodes for rechargeable lithium-ion batteries. The carbon foams have a bulk density of 0.35--0.5 g/cm{sup 3}, low surface area (< 50 m{sup 2}/g), and an average cell size of 5--10 {mu}m. Polyacrylonitrile-based carbon foams doped with phosphoric acid had capacity as high as 450 mAh/g. Carbon capacity increased with increasing phosphoric acid concentration in the doping solution. The doped porous carbon anodes exhibited good cyclability and excellent coulombic efficiency.

  9. Intercalation processes of copper complexes in DNA

    PubMed Central

    Galindo-Murillo, Rodrigo; García-Ramos, Juan Carlos; Ruiz-Azuara, Lena; Cheatham, Thomas E.; Cortés-Guzmán, Fernando

    2015-01-01

    The family of anticancer complexes that include the transition metal copper known as Casiopeínas® shows promising results. Two of these complexes are currently in clinical trials. The interaction of these compounds with DNA has been observed experimentally and several hypotheses regarding the mechanism of action have been developed, and these include the generation of reactive oxygen species, phosphate hydrolysis and/or base-pair intercalation. To advance in the understanding on how these ligands interact with DNA, we present a molecular dynamics study of 21 Casiopeínas with a DNA dodecamer using 10 μs of simulation time for each compound. All the complexes were manually inserted into the minor groove as the starting point of the simulations. The binding energy of each complex and the observed representative type of interaction between the ligand and the DNA is reported. With this extended sampling time, we found that four of the compounds spontaneously flipped open a base pair and moved inside the resulting cavity and four compounds formed stacking interactions with the terminal base pairs. The complexes that formed the intercalation pocket led to more stable interactions. PMID:25958394

  10. Lithium intercalation in porous carbon electrodes

    SciTech Connect

    Tran, T.D.; Feikert, J.; Pekala, R.W.

    1995-04-01

    Carbons derived from the phase separation of polyacrylonitrile/solvent mixtures were investigated as lithium intercalation anodes for rechargeable lithium-ion batteries. The carbon electrodes have a bulk density of 0.35-0.5 g/cm{sup 3}, relatively low surface areas (< 10 m{sup 2}/g), and micron-size cells. Pyrolysis temperature influences the reversible lithium intercalation and the irreversible capacity (associated with the formation of the passivating layer). Carbon electrodes pyrolyzed at 600{degrees}C have first-cycle capacity as high as 550 mAh/g as well as large irreversible capacity, 440 mAh/g. Electrodes prepared at 1050{degrees}C have reversible capacities around 270 mAh/g with relatively lower capacity losses (120 mAh/g). Doping the organic precursors with phosphoric acid, prior to pyrolysis at 1050{degrees}C, leads to carbon electrodes with reversible capacities as high as 450 mAh/g. The capacity of doped carbon increased with increasing phosphorus concentration in the samples. The doped carbon anodes exhibited good cycleability and excellent coulombic efficiency. The electrochemical performance is related to morphology, chemical composition, and local structural order.

  11. Plasmon characteristics in stage-1 graphene intercalation compounds

    NASA Astrophysics Data System (ADS)

    Acharya, Sidharth; Sharma, Raman

    2015-05-01

    We report the Plasmon characteristics in stage-1 graphene intercalation compounds (GIC's), using the massless Dirac fermion (MDF) gas approximation. With the discussion of the weak and the strong c-axis coupling at graphene-intercalant hetrojunction plasmon characteristics of GIC's are predicted. We have found a reasonable agreement between our results and the experimental results of Ritsko and Rice.

  12. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    PubMed Central

    Alattas, M.; Schwingenschlögl, U.

    2016-01-01

    A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy. PMID:27225324

  13. Metal intercalation-induced selective adatom mass transport on graphene

    DOE PAGESBeta

    Liu, Xiaojie; Wang, Cai -Zhuang; Hupalo, Myron; Lin, Hai -Qing; Ho, Kai -Ming; Thiel, Patricia A.; Tringides, Michael C.

    2016-03-29

    Recent experiments indicate that metal intercalation is a very effective method to manipulate the graphene-adatom interaction and control metal nanostructure formation on graphene. A key question is mass transport, i.e., how atoms deposited uniformly on graphene populate different areas depending on the local intercalation. Using first-principles calculations, we show that partially intercalated graphene, with a mixture of intercalated and pristine areas, can induce an alternating electric field because of the spatial variations in electron doping, and thus, an oscillatory electrostatic potential. As a result, this alternating field can change normal stochastic adatom diffusion to biased diffusion, leading to selective massmore » transport and consequent nucleation, on either the intercalated or pristine areas, depending on the charge state of the adatoms.« less

  14. Structural analysis of Li-intercalated hexagonal boron nitride

    SciTech Connect

    Sumiyoshi, A.; Hyodo, H.; Kimura, K.

    2012-03-15

    A structural investigation of Li-intercalated hexagonal boron nitride (Li-h-BNIC) was performed by synchrotron powder X-ray diffraction analysis and transmission electron microscopy. The host BN framework of Li-h-BNIC was expanded by Li-intercalation. The intralayer B-N bond length was increased by 2.48(1)% and the interlayer distance was expanded by 12.86(1)%. No superlattice structure of intercalated Li was observed. - Graphical abstract: XRD pattern fitting of the sample and schematic view of host h-BN lattice. Highlights: Black-Right-Pointing-Pointer Li-intercalated h-BN was investigated by synchrotron radiation powder XRD. Black-Right-Pointing-Pointer Lattice parameter of host h-BN lattice was increased by intercalation. Black-Right-Pointing-Pointer Increase ratio of B-N bond length was considerably larger than those of Li GICs.

  15. Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

    NASA Astrophysics Data System (ADS)

    Arízaga, Gregorio Guadalupe Carbajal

    2012-01-01

    Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn5(OH)8Cl2·2H2O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C.

  16. Superconductivity in the alkali metal intercalates of molybdenum disulphide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.

    1972-01-01

    The complete series of alkali metals, lithium through cesium, have been intercalated into molybdenum disulphide, using both the liquid ammonia and vapor techniques. All the intercalates with the exception of lithium yielded full superconducting transitions with onset temperatures of 6 K for AxMoS2(Ax=K,Rb,Cs) and 4 K for BxMoS2(Bx=Li,Na). The superconducting transition for lithium was incomplete down to 1.5 K. Stoichiometries and unit cell parameters have been determined for the intercalation compounds. Both rhombohedral and hexagonal polymorphs of MoS2 have been intercalated and found to exhibit the same superconductivity behavior. The nature of the extraneous superconducting transition of some intercalated samples on exposure to air was elucidated.

  17. Quasi-freestanding graphene on Ni(111) by Cs intercalation.

    PubMed

    Alattas, M; Schwingenschlögl, U

    2016-01-01

    A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy. PMID:27225324

  18. Quasi-freestanding graphene on Ni(111) by Cs intercalation

    NASA Astrophysics Data System (ADS)

    Alattas, M.; Schwingenschlögl, U.

    2016-05-01

    A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

  19. Homogeneity of pristine and bromine intercalated graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, J. R.; Marino, D.

    1985-01-01

    Wide variations in the resistivity of intercalated graphite fibers and to use these materials for electrical applications, their bulk properties must be established. The homogeneity of the diameter, the resistivity, and the mass density of 50 graphite fibers, before and after bromine intercalation was measured. Upon intercalation the diameter was found to expand by about 5%, the resistivity to decrease by a factor of five, and the density to increase by about 6%. Each individual fiber was found to have uniform diameter and resistivity over macroscopic regions for lengths as long as 7 cm. The ratio of pristine to intercalated resistivity increases as the pristine fiber diameter increases at a rate of 0.16 micron, but decreases with the increasing ratio of intercalated diameter to pristine diameter at a rate of 0.08.

  20. Intercalation of solid hydrogen into graphite under pressures

    NASA Astrophysics Data System (ADS)

    Lim, Jinhyuk; Yoo, Choong-Shik

    2016-08-01

    We present the Raman spectral evidence of pressure-induced intercalation of solid hydrogen into graphite to 60 GPa. The intercalation is evident by the emergence of two characteristic Raman bands of hydrogen (νo1 and νo2), which appear upon the solidification of hydrogen and disappear as all sp2-hybridized graphitic carbons convert to sp3-hybridized hexagonal diamond at 57 GPa. The νo1 and νo2 frequencies of intercalated hydrogen, 4250 and 4270 cm-1 at 10 GPa, are substantially higher than the νo of bulk hydrogen, 4228 cm-1 at the same pressure, indicating the presence of strong repulsive interactions between intercalated hydrogen molecules and graphite layers and, thereby, strong internal chemical pressures. Based on the spectral blue shift of intercalated hydrogen vibrons, we estimate the internal pressure to be ˜1 GPa at 10 GPa and ˜10 GPa at 50 GPa.

  1. Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

    NASA Astrophysics Data System (ADS)

    Gao, Xiaorui; Lei, Lixu; O'Hare, Dermot; Xie, Juan; Gao, Pengran; Chang, Tao

    2013-07-01

    Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg-Al and Mg-Fe layered double hydroxides (LDHs) have been synthesized by the calcination-rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV-vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO32- solutions imply that Mg3Al-VC LDH is a better controlled release system than Mg3Fe-VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and a diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO32- solution.

  2. Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

    SciTech Connect

    Gao, Xiaorui; Lei, Lixu; O'Hare, Dermot; Xie, Juan; Gao, Pengran; Chang, Tao

    2013-07-15

    Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg–Al and Mg–Fe layered double hydroxides (LDHs) have been synthesized by the calcination–rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV–vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO{sub 3}{sup 2−} solutions imply that Mg{sub 3}Al–VC LDH is a better controlled release system than Mg{sub 3}Fe–VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and a diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO{sub 3}{sup 2−} solution. - Graphical abstract: Vitamin C anions have been intercalated in the interlayer space of layered double hydroxide and released in CO{sub 3}{sup 2−} solution and deionised water. - Highlights: • Vitamin C intercalated Mg–Al and Mg–Fe layered double hydroxides were prepared. • Release property of vitamin C in aqueous CO{sub 3}{sup 2−} solution is better. • Avrami-Erofe’ev and first-order models provide better fit for release results. • Diffusion-controlled and ion exchange processes occur in deionised water. • An ion exchange process occurs in CO{sub 3}{sup 2−} solution.

  3. Influence of polymeric binder on the stability and intercalation/de-intercalation behaviour of graphite electrodes in non-aqueous solvents

    NASA Astrophysics Data System (ADS)

    Santhanam, R.; Noel, M.

    Cyclic voltammetric and scanning electron microscopic investigations on a highly-packed, crystalline, graphite electrode (HPC) and on a polypropylene composite graphite electrode (CPP) containing 20 wt.% polypropylene binder indicate that the latter has higher mechanical stability and higher electrochemical intercalation/de-intercalation activity. This holds for the intercalation of lithium (Li +) and tetrabutyl ammonium (TBA +) cations from dimethyl sulfoxide (DMSO) and dimethyl formamide (DMF), as well as for the intercalation of perchlorate (Cl0 4-) and fluoroborate (Bf 4-) anions from propylene carbonate (PC) and acetonitrile (AN). There is a linear correlation between the threshold potential for the beginning of intercalation ( Eth) and the intercalation/de-intercalation efficiency (IDE) for cationic intercalation. In the case of anionic intercalation, two distinct linear relationships for HPC and CPP electrodes are observed. Competitive oxidation processes reduce the IDE on the HPC electrode.

  4. Alkali-metal intercalation in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Béguin, F.; Duclaux, L.; Méténier, K.; Frackowiak, E.; Salvetat, J. P.; Conard, J.; Bonnamy, S.; Lauginie, P.

    1999-09-01

    We report on successful intercalation of multiwall (MWNT) and single wall (SWNT) carbon nanotubes with alkali metals by electrochemical and vapor phase reactions. A LiC10 compound was produced by full electrochemical reduction of MWNT. KC8 and CsC8-MWNT first stage derivatives were synthesized in conditions of alkali vapor saturation. Their identity periods and the 2×2 R 0° alkali superlattice are comparable to their parent graphite compounds. The dysonian shape of KC8 EPR line and the temperature-independent Pauli susceptibility are both characteristic of a metallic behavior, which was confirmed by 13C NMR anisotropic shifts. Exposure of SWNT bundles to alkali vapor led to an increase of the pristine triangular lattice from 1.67 nm to 1.85 nm and 1.87 nm for potassium and rubidium, respectively.

  5. Fabricating graphene devices from graphite intercalation compounds

    NASA Astrophysics Data System (ADS)

    Yagi, Ryuta; Shimomura, Midori; Tahara, Fumiya; Fukada, Seiya

    2013-03-01

    We report a method of making few-layer graphene flakes by mechanically exfoliating SbCl5-graphite intercalation compounds (GICS). The number of exfoliated graphene flakes had a peculiar distribution relevant to the stage structure of GICs. The carrier doping of the few-layer graphene flakes was about two orders of magnitude smaller than that expected from the stoichiometry of the GICs. The measured electric mobility was comparable to that made from pristine graphite. The EPMA measurement showed that inhomogeneous distribution of dopant near the surface of GIC was responsible for obtaining the virtually undoped graphene. Deintercalation of dopant would expand interlayer distance of each graphene layer, and thereby layer-number of exfoliated graphene depended stage number of GIC.

  6. Intercalation compounds involving inorganic layered structures

    PubMed

    Constantino; Barbosa; Bizeto; Dias

    2000-01-01

    Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts. PMID:10932103

  7. Carbonaceous materials as lithium intercalation anodes

    SciTech Connect

    Tran, T.D.; Feikert, J.H.; Mayer, S.T.; Song, X.; Kinoshita, K.

    1994-10-01

    Commercial and polymer-derived carbonaceous materials were examined as lithium intercalation anodes in propylene carbonate (pyrolysis < 1350C, carbons) and ethylene carbonate/dimethyl carbonate (graphites) electrolytes. The reversible capacity (180--355 mAh/g) and the irreversible capacity loss (15--200 % based on reversible capacity) depend on the type of binder, carbon type, morphology, and phosphorus doping concentration. A carbon-based binder was chosen for electrode fabrication, producing mechanically and chemically stable electrodes and reproducible results. Several types of graphites had capacity approaching LiC{sub 6}. Petroleum fuel green cokes doped with phosphorous gave more than a 20 % increase in capacity compared to undoped samples. Electrochemical characteristics are related to SEM, TEM, XRD and BET measurements.

  8. Intercalation of hexagonal boron nitride with potassium

    SciTech Connect

    Doll, G.L.; Speck, J.S.; Dresselhaus, G.; Dresselhaus, M.S. ); Nakamura, K.; Tanuma, S.

    1989-09-15

    We have performed photoluminescence, photoexcitation, and transmission electron microscopy measurements on boron nitride films grown by chemical vapor deposition and later reacted with potassium. After reaction, the potassium atoms were found to intercalate the BN host and to form a (2{times}2){ital R}0{degree} in-plane structure which is commensurate with the pristine BN lattice. Optical transitions with {similar to}2.7 eV onsets were found to occur within the {similar to}5-eV BN band gap and have been interpreted as {Gamma}-point transitions between the K(4{ital s}) band and the BN(2{ital p}) bands. The absence of an appreciable shift in the {ital E}{sub 2{ital g}{sub 2}} phonon frequency of the pristine and reacted films suggests that the charge transfer between the K and BN bands is very small.

  9. Synthesis and characterization of Mn intercalated Mg-Al hydrotalcite.

    PubMed

    Yang, Chengxue; Liao, Libing; Lv, Guocheng; Wu, Limei; Mei, Lefu; Li, Zhaohui

    2016-10-01

    Mn intercalated hydrotalcite was prepared using a reconstruction method. And Mn intercalation was confirmed by XRD, FTIR, and thermal analyses. The different valences of Mn were present as determined by XPS. Calcination slightly promoted the isomorphic replacement of Mn(2+) and Mn(3+) for Mg(2+) and Al(3+), especially the replacement of Mn(2+) for Mg(2+) and Al(3+), and to some extent, reduced Mn intercalation. Ultrasonic treatment significantly increased Mn intercalation in permanganate form (Mn(7+)), and promoted the replacement of Mn(2+) for Mg(2+) and Al(3+). XRF analysis showed that ultrasonic treatment decreased the unbalanced layer charge of Mn intercalated hydrotalcite, while prolonged calcination increased it. These results may provide guidance on the preparation and application of Mn intercalated hydrotalcite. Extended calcination time and ultrasonic vibration increased the interlayer spacing of hydrotalcite, as a result of reduction in layer charge. As the layer charge was not completely balanced after Mn intercalation, a certain amount of CO3(2-) was re-adsorbed into the interlayer space. Mn-hydrotalcites with different layer charges, different contents of Mn with varying valences are expected to have different performances in the process of adsorption, degradation, and catalysis. PMID:27380016

  10. Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

    SciTech Connect

    Arizaga, Gregorio Guadalupe Carbajal

    2012-01-15

    Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn{sub 5}(OH){sub 8}Cl{sub 2}{center_dot}2H{sub 2}O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 Degree-Sign C while the exothermic event in ZHN was 366 Degree-Sign C and in the LDH at 276 Degree-Sign C. - Graphical abstract: The zinc hydroxide chloride (ZHC) with formula Zn{sub 5}(OH){sub 8}Cl{sub 2}{center_dot}2H{sub 2}O was tested as intercalation matrix. In comparison with the well-known zinc hydroxide nitrate (ZHN) and layered double hydroxides (LDH), ZHC was the best matrix for thermal protection of Asp combustion, presenting exothermic peaks even at 452 Degree-Sign C, while the highest exothermic event in ZHN was at 366 Degree-Sign C, and in the LDH it was at 276 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Zinc hydroxide chloride (ZHC) was tested as intercalation matrix for the first time. Black-Right-Pointing-Pointer ZHC has higher chemical and thermal stability than zinc hydroxide nitrate and LDH. Black-Right-Pointing-Pointer NH{sub 3} molecules can be intercalated into ZHC. Black-Right-Pointing-Pointer The amino group of amino acids limits the intercalation by ion-exchange.

  11. Amine-intercalated α-zirconium phosphates as lubricant additives

    NASA Astrophysics Data System (ADS)

    Xiao, Huaping; Dai, Wei; Kan, Yuwei; Clearfield, Abraham; Liang, Hong

    2015-02-01

    In this study, three types of amines intercalated α-zirconium phosphate nanosheets with different interspaces were synthesized and examined as lubricant additives to a mineral oil. Results from tribological experiments illustrated that these additives improved lubricating performance. Results of rheological experiments showed that the viscosity of the mineral oil was effectively reduced with the addition of α-zirconium phosphate nanosheets. The two-dimensional structure, with larger interspaces, resulting from amine intercalation, exhibited improved effectiveness in reducing viscosity. This study demonstrates that the nanosheet structure of α-zirconium phosphates is effective in friction reduction. The manufacture of lubricants with tailored viscosity is possible by using different intercalators.

  12. Prediction of superconductivity in Li-intercalated bilayer phosphorene

    SciTech Connect

    Huang, G. Q.; Xing, Z. W.; Xing, D. Y.

    2015-03-16

    It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature T{sub c} can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor.

  13. Dissecting the Dynamic Pathways of Stereoselective DNA Threading Intercalation.

    PubMed

    Almaqwashi, Ali A; Andersson, Johanna; Lincoln, Per; Rouzina, Ioulia; Westerlund, Fredrik; Williams, Mark C

    2016-03-29

    DNA intercalators that have high affinity and slow kinetics are developed for potential DNA-targeted therapeutics. Although many natural intercalators contain multiple chiral subunits, only intercalators with a single chiral unit have been quantitatively probed. Dumbbell-shaped DNA threading intercalators represent the next order of structural complexity relative to simple intercalators, and can provide significant insights into the stereoselectivity of DNA-ligand intercalation. We investigated DNA threading intercalation by binuclear ruthenium complex [μ-dppzip(phen)4Ru2](4+) (Piz). Four Piz stereoisomers are defined by the chirality of the intercalating subunit (Ru(phen)2dppz) and the distal subunit (Ru(phen)2ip), respectively, each of which can be either right-handed (Δ) or left-handed (Λ). We used optical tweezers to measure single DNA molecule elongation due to threading intercalation, revealing force-dependent DNA intercalation rates and equilibrium dissociation constants. The force spectroscopy analysis provided the zero-force DNA binding affinity, the equilibrium DNA-ligand elongation Δxeq, and the dynamic DNA structural deformations during ligand association xon and dissociation xoff. We found that Piz stereoisomers exhibit over 20-fold differences in DNA binding affinity, from a Kd of 27 ± 3 nM for (Δ,Λ)-Piz to a Kd of 622 ± 55 nM for (Λ,Δ)-Piz. The striking affinity decrease is correlated with increasing Δxeq from 0.30 ± 0.02 to 0.48 ± 0.02 nm and xon from 0.25 ± 0.01 to 0.46 ± 0.02 nm, but limited xoff changes. Notably, the affinity and threading kinetics is 10-fold enhanced for right-handed intercalating subunits, and 2- to 5-fold enhanced for left-handed distal subunits. These findings demonstrate sterically dispersed transition pathways and robust DNA structural recognition of chiral intercalators, which are critical for optimizing DNA binding affinity and kinetics. PMID:27028636

  14. The intercalation of DNA double helices with doxorubicin and nogalamycin.

    PubMed

    Box, Vernon G S

    2007-07-01

    A variety of molecules bind to DNA in its major and minor grooves, and some, like the anthraquinoids, are known to form intercalates in which these molecules are inserted directly into the double helix, between the bases. Several researchers have pointed to an electron transfer mechanism (leading to ion pairing) as one of the factors that could hold the intercalated entities like doxorubicin in place, but the bulky anthraquinone nogalamycin did not seem to become engaged in electron transfer. The molecular modeling program STR3DI32 was used to investigate the stabilities of these intercalated anthraquinone before any possible electron transfer has occurred. PMID:17046298

  15. Intercalated samarium as an agent enabling the intercalation of oxygen under a monolayer graphene film on iridium

    NASA Astrophysics Data System (ADS)

    Afanas'eva, E. Yu.; Rut'kov, E. V.; Gall', N. R.

    2016-06-01

    Using thermal desorption time-of-flight mass spectrometry and thermionic methods, it is shown that oxygen does not intercalate under a graphene monolayer grown correctly on iridium, at least at temperatures of T = 300-400 K and exposures below 12000 L. However, if the graphene film on iridium is preliminary intercalated with samarium atoms (up to coverage of θSm = 0.2-0.45), the penetration of oxygen atoms under the graphene film is observed. The oxygen atoms in the intercalated state are chemically bonded to samarium atoms and remain under graphene up to high temperatures (~2150 K).

  16. Intercalation of a block co-polymer in kaolinite.

    PubMed

    Fafard, Jonathan; Detellier, Christian

    2015-07-15

    Intercalates of kaolinite/Polyethylene-block-poly (ethylene glycol) were successfully prepared by melt intercalation of the polymer with a kaolinite: dimethyl sulfoxide pre-intercalate. Powder X-ray diffraction gives an 11.05 Å d-spacing which remains after washing the material with water. Thermal gravimetric analysis and nuclear magnetic resonance confirm the presence of the polymer in the prepared material. Perturbation of the kaolinite hydroxyl stretch and the polymer's CH2 bending modes in the materials' infrared spectrum suggest strong interaction between the aluminol clay sheet and the ethylene glycol units in the polymer. Dipolar dephasing studies show both polymer blocks experience a significant loss in mobility in the prepared material, indicative of intercalation. The presence of highly hydrophobic polyethylene inside kaolinite is expected to drastically modify the nature of the interlayer space, and could be of interest for applications where retention or sequestration of hydrophobic species is required. PMID:25841062

  17. Kidney α-Intercalated Cells, NGAL and Urinary Tract Infection

    PubMed Central

    Chen, Lihe; Zhang, Wenzheng

    2016-01-01

    It is well known that kidney α-intercalated cells can acidify the urine and acidified urine can inhibit bacterial growth and other urinary organisms. However, regulation of acid-base balance rather than a dedicated function in preventing urinary tract infection has been assigned to α-intercalated cells. A series of studies, culminated by the publication of a paper (J Clin Invest. 2014 Jul 1;124(7):2963–76) from Dr. Barasch’s lab unearthed a novel mechanism by which α-intercalated cells function in the innate immune defense of urinary tract infection. This mechanism involves production and release of neutrophil gelatinase-associated lipocalin by α-intercalated cells to chelate the siderophore containing host iron to achieve bacteriostasis.

  18. Method for intercalating alkali metal ions into carbon electrodes

    DOEpatents

    Doeff, M.M.; Ma, Y.; Visco, S.J.; DeJonghe, L.

    1995-08-22

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  19. Method for intercalating alkali metal ions into carbon electrodes

    DOEpatents

    Doeff, Marca M.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard

    1995-01-01

    A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

  20. Graphitized needle cokes and natural graphites for lithium intercalation

    SciTech Connect

    Tran, T.D.; Spellman, L.M.; Pekala, R.W.; Goldberger, W.M.; Kinoshita, K.

    1996-05-10

    This paper examined effects of heat treatment and milling (before or after heat treatment) on the (electrochemical) intercalating ability of needle petroleum coke; natural graphite particles are included for comparison. 1 tab, 4 figs, 7 refs.

  1. Intercalation-driven reversible control of magnetism in bulk ferromagnets.

    PubMed

    Dasgupta, Subho; Das, Bijoy; Knapp, Michael; Brand, Richard A; Ehrenberg, Helmut; Kruk, Robert; Hahn, Horst

    2014-07-16

    An extension in magnetoelectric effects is proposed to include reversible chemistry-controlled magnetization variations. This ion-intercalation-driven magnetic control can be fully reversible and pertinent to bulk material volumes. The concept is demonstrated for ferromagnetic iron oxide where the intercalated lithium ions cause valence change and partial redistribution of Fe(3+) cations yielding a large and fully reversible change in magnetization at room temperature. PMID:24591165

  2. Effect of Diffusion on Lithium Intercalation in Titanium Dioxide

    NASA Astrophysics Data System (ADS)

    Koudriachova, Marina V.; Harrison, Nicholas M.; de Leeuw, Simon W.

    2001-02-01

    A new model of Li intercalation into rutile and anatase structured titania has been developed from first principles calculations. The model includes both thermodynamic and kinetic effects and explains the observed differences in intercalation behavior and their temperature dependence. The important role of strong local deformations of the lattice and elastic screening of interlithium interactions is demonstrated. In addition, a new phase of LiTiO2 is reported.

  3. Electronic Band Engineering of Epitaxial Graphene by Atomic Intercalation

    NASA Astrophysics Data System (ADS)

    Jayasekera, Thushari; Sandin, Andreas; Xu, Shu; Wheeler, Virginia; Gaskill, D. K.; Rowe, J. E.; Kim, K. W.; Dougherty, Daniel B.; Buongiorno Nardelli, M.

    2012-02-01

    Using calculations from first principles, we have investigated possible ways of engineering the electronic band structure of epitaxial graphene on SiC. In particular, intercalation of different atomic species, such as Hydrogen, Fluorine, Sodium, Germanium, Carbon and Silicon is shown to modify and tune the interface electronic properties and band alignments. Our results suggest that intercalation in graphene is quite different from that in graphite, and could provide a fundamentally new way to achieve electronic control in graphene electronics.

  4. Electronic properties of carbon fibers intercalated with copper chloride

    NASA Technical Reports Server (NTRS)

    Oshima, H.; Natarajan, V.; Woollam, J. A.; Yavrouian, A.; Haugland, E. J.; Tsuzuku, T.

    1984-01-01

    Copper chloride intercalated pitch-based carbon fibers are found to have electrical resistivities as low as 12.9 micro-ohm-cm, and are air- and thermally-stable at and above room temperature. This is therefore a good candidate system for conductor application. In addition, Shubnikov-deHaas quantum oscillatory effects were found, and electronic properties of the intercalated fiber are studied using magnetic fields to 20 tesla.

  5. Obtaining graphene nanoplatelets from various graphite intercalation compounds

    NASA Astrophysics Data System (ADS)

    Melezhyk, A.; Galunin, E.; Memetov, N.

    2015-11-01

    The work compares the exfoliation ability of different graphite materials (expanded graphite intercalation compound, thermally expanded and oxidatively intercalated graphites) and describes the properties of graphene nanoplatelets (GNPs) obtained dependently on intercalation/deintercalation conditions and reagents. Among the studied materials, the graphite intercalated with ammonium persulfate in sulfuric acid and expanded at 40 °C possesses the maximum ability for ultrasonic exfoliation in the presence of a surfactant. The exfoliation efficiency strongly depends on the content of water in sulfuric acid during the intercalation. The highest efficiency was achieved for the expanded graphite intercalation compound (EGIC) prepared in sulfuric acid containing diluted oleum, which may be explained by increased acidity of the medium and, correspondingly, redox potential of the persulfate compound. This is also related to increased amounts of oxygen groups in the GNPs obtained from the EGIC synthesized in 100% sulfuric acid and diluted oleum. Besides, the nature of surface groups on the GNPs strongly depends on the nature of a deintercalating reagent. Thus, the treatment of the EGIC with different nucleophilic molecules (such as water, ammonia, carbamide, hexamethylenetetramine, organic amines, etc.) can yield GNPs with various surface groups. The interaction between the EGIC and nucleophilic molecules does not only include the substitution of sulfate groups, but also redox reactions with participation of graphene layers. Depending on the nature of the nucleophile, those reactions can lead to the formation of different groups attached to the graphene surface. GNPs with almost pure surface were obtained when using ammonia and carbamide.

  6. Stochastic Terminal Dynamics in Epithelial Cell Intercalation

    NASA Astrophysics Data System (ADS)

    Eule, Stephan; Metzger, Jakob; Reichl, Lars; Kong, Deqing; Zhang, Yujun; Grosshans, Joerg; Wolf, Fred

    2015-03-01

    We found that the constriction of epithelial cell contacts during intercalation in germ band extension in Drosophila embryos follows intriguingly simple quantitative laws. The mean contact length < L > follows < L > (t) ~(T - t) α , where T is the finite collapse time; the time dependent variance of contact length is proportional to the square of the mean; finally the time dependent probability density of the contact lengths remains close to Gaussian during the entire process. These observations suggest that the dynamics of contact collapse can be captured by a stochastic differential equation analytically tractable in small noise approximation. Here, we present such a model, providing an effective description of the non-equilibrium statistical mechanics of contact collapse. All model parameters are fixed by measurements of time dependent mean and variance of contact lengths. The model predicts the contact length covariance function that we obtain in closed form. The contact length covariance function closely matches experimental observations suggesting that the model well captures the dynamics of contact collapse.

  7. Space Discovery.

    ERIC Educational Resources Information Center

    Blackman, Joan

    1998-01-01

    Describes one teacher's experience taking Space Discovery courses that were sponsored by the United States Space Foundation (USSF). These courses examine the history of space science, theory of orbits and rocketry, the effects of living in outer space on humans, and space weather. (DDR)

  8. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

    PubMed

    Banerjee, T; Banerjee, S; Sett, S; Ghosh, S; Rakshit, T; Mukhopadhyay, R

    2016-01-01

    DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time. PMID:27183010

  9. Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy

    PubMed Central

    Sett, S.; Ghosh, S.; Rakshit, T.; Mukhopadhyay, R.

    2016-01-01

    DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA—the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA—the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time. PMID:27183010

  10. Application of photochemical reaction in electrochemical detection of DNA intercalation.

    PubMed

    Pandey, P C; Weetall, H H

    1994-04-15

    A flow injection analysis (FIA) system for the detection of the compounds that intercalate within DNA is reported. A derivative of 9,10-anthraquinone has been used as the reference compound for photoelectrochemical detection. The sodium salts of 9,10-anthraquinone-2,6-disulfonic acid and 9,10-anthraquinone-2-sulfonic acid are photochemically activated and then reduced in the presence of an electron donor (glucose). The electrochemical signal is based on the measurement of the anodic current resulting from the oxidation of the reduced form of 9,10-anthraquinone. The reduced form of the 9,10-anthraquinone is oxidized through a mediated mechanism at the surface of a tetracyanoquinodimethane-(TCNQ)-modified graphite paste electrode covered by a Nucleopore membrane. TCNQ acts as an efficient mediator for the oxidation of reduced 9,10-anthraquinone. Cyclic voltammetry, photocyclic voltammetry, and the photoelectrochemical FIA response of 9,10-anthraquinone are reported. Experimental results show that these anthraquinones can be intercalated within the helix of double-stranded calf thymus DNA. The anthraquinone molecules that are intercalated within DNA cannot be oxidized due to their limited transport to the modified electrode surface. This results in a decrease in the anodic current at a constant concentration of anthraquinone after intercalation. There is a linear relation between the decrease in electrochemical response and the DNA concentration at a constant concentration of anthraquinone. The intercalated anthraquinone molecules can be completely replaced by another intercalating agent (i.e., ethidium bromide) that is more strongly intercalated within DNA, thereby regenerating the electrochemical response.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8210041

  11. The preliminary feasibility of intercalated graphite railgun armatures

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Gooden, Clarence E.; Yashan, Doreen; Naud, Steve

    1991-01-01

    Graphite intercalation compounds may provide an excellent material for the fabrication of electromagnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  12. The preliminary feasibility of intercalated graphite railgun armatures

    SciTech Connect

    Gaier, J.R. . Lewis Research Center); Gooden, C.E. ); Yashan, D. ); Naud, S. )

    1991-01-01

    This paper reports on graphite intercalation compounds which may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite.

  13. Intercalation of ethylene glycol into yttrium hydroxide layered materials.

    PubMed

    Xi, Yuanzhou; Davis, Robert J

    2010-04-19

    Intercalation of ethylene glycol into layered yttrium hydroxide containing nitrate counterions was accomplished by heating the reagents in a methanol solution of sodium methoxide under autogenous pressure at 413 K for 20 h. The resulting crystalline material had an expanded interlayer distance of 10.96 A, confirming the intercalation of an ethylene glycol derived species. Characterization of the material by FT-IR spectroscopy, thermogravimetric analysis, and the catalytic transesterification of tributyrin with methanol was consistent with direct bonding of ethylene glycolate anions (O(2)C(2)H(5)(-)) to the yttrium hydroxide layers, forming Y-O-C bonds. The layers of the material are proposed to be held together by H-bonding between the hydroxyls of grafted ethylene glycol molecules attached to adjacent layers. Glycerol can also be intercalated into yttrium hydroxide layered materials by a similar method. PMID:20302308

  14. The backside of graphene: manipulating adsorption by intercalation.

    PubMed

    Schumacher, Stefan; Wehling, Tim O; Lazić, Predrag; Runte, Sven; Förster, Daniel F; Busse, Carsten; Petrović, Marin; Kralj, Marko; Blügel, Stefan; Atodiresei, Nicolae; Caciuc, Vasile; Michely, Thomas

    2013-11-13

    The ease by which graphene is affected through contact with other materials is one of its unique features and defines an integral part of its potential for applications. Here, it will be demonstrated that intercalation, the insertion of atomic layers in between the backside of graphene and the supporting substrate, is an efficient tool to change its interaction with the environment on the frontside. By partial intercalation of graphene on Ir(111) with Eu or Cs we induce strongly n-doped graphene patches through the contact with these intercalants. They coexist with nonintercalated, slightly p-doped graphene patches. We employ these backside doping patterns to directly visualize doping induced binding energy differences of ionic adsorbates to graphene through low-temperature scanning tunneling microscopy. Density functional theory confirms these binding energy differences and shows that they are related to the graphene doping level. PMID:24131290

  15. Intercalation of paracetamol into the hydrotalcite-like host

    SciTech Connect

    Kovanda, Frantisek; Maryskova, Zuzana; Kovar, Petr

    2011-12-15

    Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg-Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 Degree-Sign C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals. - Graphical abstract: Molecular simulations showed disordered arrangement of paracetamol molecules in the interlayer; most of the interlayer water molecules are located near the hydroxide sheets. Black-Small-Square Highlights: Black-Right-Pointing-Pointer Paracetamol was intercalated in Mg-Al hydrotalcite-like host by rehydration/reconstruction procedure. Black-Right-Pointing-Pointer Paracetamol phenolic groups interact with positively charged sites in hydroxide sheets. Black-Right-Pointing-Pointer Molecular simulations showed disordered arrangement of guest molecules in the interlayer. Black-Right-Pointing-Pointer Slower release of paracetamol intercalated in the hydrotalcite-like host was observed.

  16. Preparation of graphite intercalation compounds containing oligo and polyethers

    NASA Astrophysics Data System (ADS)

    Zhang, Hanyang; Lerner, Michael M.

    2016-02-01

    Layered host-polymer nanocomposites comprising polymeric guests between inorganic sheets have been prepared with many inorganic hosts, but there is limited evidence for the incorporation of polymeric guests into graphite. Here we report for the first time the preparation, and structural and compositional characterization of graphite intercalation compounds (GICs) containing polyether bilayers. The new GICs are obtained by either (1) reductive intercalation of graphite with an alkali metal in the presence of an oligo or polyether and an electrocatalyst, or (2) co-intercalate exchange of an amine for an oligo or polyether in a donor-type GIC. Structural characterization of products using powder X-ray diffraction, Raman spectroscopy, and thermal analyses supports the formation of well-ordered, first-stage GICs containing alkali metal cations and oligo or polyether bilayers between reduced graphene sheets.Layered host-polymer nanocomposites comprising polymeric guests between inorganic sheets have been prepared with many inorganic hosts, but there is limited evidence for the incorporation of polymeric guests into graphite. Here we report for the first time the preparation, and structural and compositional characterization of graphite intercalation compounds (GICs) containing polyether bilayers. The new GICs are obtained by either (1) reductive intercalation of graphite with an alkali metal in the presence of an oligo or polyether and an electrocatalyst, or (2) co-intercalate exchange of an amine for an oligo or polyether in a donor-type GIC. Structural characterization of products using powder X-ray diffraction, Raman spectroscopy, and thermal analyses supports the formation of well-ordered, first-stage GICs containing alkali metal cations and oligo or polyether bilayers between reduced graphene sheets. Electronic supplementary information (ESI) available: Domain size, additional Raman spectra info, compositional calculation, and packing fractions. See DOI: 10.1039/c5

  17. Revisiting the domain model for lithium intercalated graphite

    SciTech Connect

    Krishnan, Sridevi; Brenet, Gilles; Caliste, Damien; Genovese, Luigi; Deutsch, Thierry; Pochet, Pascal

    2013-12-16

    In this Letter, we study the stability of the domain model for lithium intercalated graphite in stages III and II by means of Density Functional Theory and Kinetic Lattice Monte Carlo simulations. We find that the domain model is either thermodynamically or kinetically stable when compared to the standard model in stages III and II. The existence of domains in the intercalation sequence is well supported by recent high resolution transmission electron microscope observations in lithiated graphite. Moreover, we predict that such domain staging sequences leads to a wide range of diffusivity as reported in experiments.

  18. Layered Compounds and Intercalation Chemistry: An Example of Chemistry and Diffusion in Solids.

    ERIC Educational Resources Information Center

    Whittingham, M. Stanley; Chianelli, Russell R.

    1980-01-01

    Considers a few areas of oxide/sulfide and intercalation-type chemistry. Discusses synthesis of the disulfides of the metals of group IVB, VB, and VIB; the intercalation reaction between lithium and titanium disulfide; other intercalates; and sulfide catalysts. (CS)

  19. Discovery Scarp

    NASA Technical Reports Server (NTRS)

    1974-01-01

    One of the most prominent lobate scarps (Discovery Scarp), photographed by Mariner 10 during it's first encounter with Mercury, is located at the center of this image (extending from the top to near bottom). This scarp is about 350 kilometers long and transects two craters 35 and 55 kilometers in diameter. The maximum height of the scarp south of the 55-kilometer crater is about 3 kilometers. Notice the shallow older crater (near the center of the image) perched on the crest of the scarp. (FDS 17389 and 27399)

    The Mariner 10 mission, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, explored Venus in February 1974 on the way to three encounters with Mercury-in March and September 1974 and in March 1975. The spacecraft took more than 7,000 photos of Mercury, Venus, the Earth and the Moon.

    Image Credit: NASA/JPL/Northwestern University

  20. Intercalation of paracetamol into the hydrotalcite-like host

    NASA Astrophysics Data System (ADS)

    Kovanda, František; Maryšková, Zuzana; Kovář, Petr

    2011-12-01

    Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg-Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 °C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals.

  1. Intercalation of papain enzyme into hydrotalcite type layered double hydroxide

    NASA Astrophysics Data System (ADS)

    Zou, N.; Plank, J.

    2012-09-01

    Intercalation of proteolytic enzyme papain into hydrotalcite type LDH structure was achieved by controlled co-precipitation at pH=9.0 in the presence of papain. Characterization of the MgAl-papain-LDH phase was carried out using X-ray powder diffraction (XRD), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). According to XRD, papain was successfully intercalated. The d-value for the basal spacing of MgAl-papain-LDH was found at ˜5.3 nm. Consequently, original papain (hydrodynamic diameter ˜7.2 nm) attains a compressed conformation during intercalation.Formation of MgAl-papain-LDH was confirmed by elemental analysis and transmission electron microscopy (TEM). Under SEM, MgAl-papain-LDH phases appear as nanothin platelets which are intergrown to flower-like aggregates. Steric size and activity of the enzyme was retained after deintercalation from MgAl-LDH framework, as was evidenced by light scattering and UV/vis measurements. Thus, papain is not denatured during intercalation, and LDH is a suitable host structure which can provide a time-controlled release of the biomolecule.

  2. Exfoliation of Hexagonal Boron Nitride via Ferric Chloride Intercalation

    NASA Technical Reports Server (NTRS)

    Hung, Ching-cheh; Hurst, Janet; Santiago, Diana; Rogers, Richard B.

    2014-01-01

    Sodium fluoride (NaF) was used as an activation agent to successfully intercalate ferric chloride (FeCl3) into hexagonal boron nitride (hBN). This reaction caused the hBN mass to increase by approx.100 percent, the lattice parameter c to decrease from 6.6585 to between 6.6565 and 6.6569 ?, the x-ray diffraction (XRD) (002) peak to widen from 0.01deg to 0.05deg of the full width half maximum value, the Fourier transform infrared (FTIR) spectrum's broad band (1277/cm peak) to change shape, and new FTIR bands to emerge at 3700 to 2700 and 1600/cm. This indicates hBN's structural and chemical properties are significantly changed. The intercalated product was hygroscopic and interacted with moisture in the air to cause further structural and chemical changes (from XRD and FTIR). During a 24-h hold at room temperature in air with 100 percent relative humidity, the mass increased another 141 percent. The intercalated product, hydrated or not, can be heated to 750 C in air to cause exfoliation. Exfoliation becomes significant after two intercalation-air heating cycles, when 20-nm nanosheets are commonly found. Structural and chemical changes indicated by XRD and FTIR data were nearly reversed after the product was placed in hydrochloric acid (HCl), resulting in purified, exfoliated, thin hBN products.

  3. Kinetics of the Formation of Intercalation Compounds in Crystalline Graphite

    NASA Technical Reports Server (NTRS)

    Sharma, P. K.; Hickey, G. S.

    1995-01-01

    Crystalline graphite has a structure that can be best described as an ordered stack of flat aromatic layers. It is known to form intercalation compounds with bromine and nitric acid. Their formation was studied using thermal measurements and analytical techniques. Samples of graphite treated with either bromine or nitric acid were prepared by contacting these reagents with powdered graphite.

  4. Capacitive Sensing of Intercalated H2O Molecules Using Graphene.

    PubMed

    Olson, Eric J; Ma, Rui; Sun, Tao; Ebrish, Mona A; Haratipour, Nazila; Min, Kyoungmin; Aluru, Narayana R; Koester, Steven J

    2015-11-25

    Understanding the interactions of ambient molecules with graphene and adjacent dielectrics is of fundamental importance for a range of graphene-based devices, particularly sensors, where such interactions could influence the operation of the device. It is well-known that water can be trapped underneath graphene and its host substrate; however, the electrical effect of water beneath graphene and the dynamics of how the interfacial water changes with different ambient conditions has not been quantified. Here, using a metal-oxide-graphene variable-capacitor (varactor) structure, we show that graphene can be used to capacitively sense the intercalation of water between graphene and HfO2 and that this process is reversible on a fast time scale. Atomic force microscopy is used to confirm the intercalation and quantify the displacement of graphene as a function of humidity. Density functional theory simulations are used to quantify the displacement of graphene induced by intercalated water and also explain the observed Dirac point shifts as being due to the combined effect of water and oxygen on the carrier concentration in the graphene. Finally, molecular dynamics simulations indicate that a likely mechanism for the intercalation involves adsorption and lateral diffusion of water molecules beneath the graphene. PMID:26502269

  5. [Raman and infrared spectrograms of organic borate intercalated hydrotalcite].

    PubMed

    Zhang, Jing-Yu; Bai, Zhi-Min; Zhao, Dong

    2013-03-01

    The pattern of X-ray diffraction, the Raman and infrared spectra of organic borate intercalated hydrotalcite were discussed. The well crystallized zinc-aluminum layered double hydroxides (Zn-Al LDHs) intercalated by carbonate ions and borate ions were respectively prepared by co-precipitation method. Patterns of X-ray diffraction showed that the (003) reflection of borate-LDHs was sharp and symmetric and shifted to lower angle than that of carbonate-LDHs. The gallery height of borate-LDHs increased from 0. 28 nm to 0.42 nm after intercalation, indicating that interlayered carbonate ions were substituted by borate anions. The Raman and IR spectra showed that specific bands of carbonate ions in the borate-LDHs disappeared, but with the presence of B3O3(OH)4- X B4O5(OH)4(2-) and B(OH)4- in the interlayer galleries. The hydroxide interlayer anions had a significant influence on the band positions in Raman and infrared spectra of modes related to the hydroxyl group. Our results indicate that single phase and pure borate-pillared LDHs can be obtained using tributyl orthoborate as intercalating agents, and the change in the structure and nature of hydrotalcite can be detected precisely by Raman spectroscopy. PMID:23705437

  6. Tethered naphthalene diimide-based intercalators for DNA triplex stabilization

    PubMed Central

    Gianolio, Diego A.; Segismundo, Joanna M.; McLaughlin, Larry W.

    2000-01-01

    The synthesis and triplex stabilizing properties of oligodeoxyribonucleotides functionalized at the 5′- and/or 3′-termini with a naphthalene diimide-based (NDI) intercalator is described. The NDI intercalator was prepared in a single step from the corresponding dianhydride and was attached to the 5′-terminus of an oligodeoxyribonucleotide following a reverse coupling procedure. The DMT protecting group was removed and the sequence phosphitylated to generate the phosphoramidite derivative on the 5′-terminus of the support-bound oligodeoxyribonucleotide. The NDI intercalator with a free hydroxyl was then added in the presence of tetrazole. Attachment of the NDI to the 3′-terminus relied upon a tethered amino group that could be functionalized first with the naphthalene dianhydride, which was subsequently converted to the diimide. Using both procedures, an oligonucleotide conjugate was prepared having the NDI intercalator at both the 5′- and 3′-termini. Thermal denaturation studies were used to determine the remarkable gain in stability for triplexes formed when the NDI-conjugated oligonucleotide was present as the third strand in the complex. PMID:10773082

  7. Methotrexate intercalated ZnAl-layered double hydroxide

    SciTech Connect

    Chakraborty, Manjusha; Dasgupta, Sudip; Soundrapandian, Chidambaram; Chakraborty, Jui; Ghosh, Swapankumar; Mitra, Manoj K.; Basu, Debabrata

    2011-09-15

    The anticancerous drug methotrexate (MTX) has been intercalated into an ZnAl-layered double hydroxide (LDH) using an anion exchange technique to produce LDH-MTX hybrids having particle sizes in the range of 100-300 nm. X-ray diffraction studies revealed increases in the basal spacings of ZnAl-LDH-MTX hybrid on MTX intercalation. This was corroborated by the transmission electron micrographs, which showed an increase in average interlayer spacing from 8.9 A in pristine LDH to 21.3 A in LDH-MTX hybrid. Thermogravimetric analyses showed an increase in the decomposition temperature for the MTX molecule in the LDH-MTX hybrid indicating enhanced thermal stability of the drug molecule in the LDH nanovehicle. The cumulative release profile of MTX from ZnAl-LDH-MTX hybrids in phosphate buffer saline (PBS) at pH 7.4 was successfully sustained for 48 h following Rigter-Peppas model release kinetics via diffusion. - Graphical abstract: ZnAl-layered double hydroxide intercalated with methotrexate ({approx}34% loading) promises the possibility of use of ZnAl-LDH material as drug carrier and in controlled delivery. Highlights: > ZnAl-layered double hydroxide methotrexate nanohybrid has been synthesized. > XRD and TEM studies on nanohybrid revealed successful intercalation of methotrexate. > TG and CHN analyses showed {approx}34 wt% of methotrexate loading into the nanohybrid. > Possibility of use of ZnAl-LDH material as drug carrier and in delivery.

  8. Formation of intercalated illite and kaolinite in the meteoric environment

    SciTech Connect

    Stonecipher, S.A. )

    1990-05-01

    Intercalations of illite and kaolinite are common diagenetic products in many sandstones. Most literature references suggest that these intercalations formed by the progressive growth of illite within preexisting vermiform kaolinite. This process of illitization has been related to the progressive release of potassium from feldspars and micas during middle- to late-stage burial diagenesis. The application of similar time and process connotations to all intercalations of illite and kaolinite is not justified, however. Petrographic studies of sands of different origins have revealed intercalations of kaolinite and illite which appear to have resulted from the progressive growth of kaolinite on or in between the layers of preexisting clay or mica sheets. Expansion of degraded micas in confining pore spaces produced accordion-like structures. Similarly oriented layers in the accordion were infilled with kaolinite producing pseudovermiform booklets. In each case, the kaolinite appears to have formed early in the sand's diagenetic history before much compaction took place. Examples of this fabric will be shown from diverse settings. Provenance, age, and geographic location vary widely; however, in all cases, the sands were deposited in deltaic to shoreline environments which were subjected to extensive meteoric flushing during deposition and early burial. The kaolinite appears to have formed in response to leaching and dissolution of micas and clays in the meteoric environment. This interpretation raises a caveat for petrologists; the determination of which came first, the kaolinite or the intercalated clay, has serious implications not only for the timing and origin of the kaolinite, but also for the depositional setting of the enclosing sand.

  9. Technical Report-Final-Electrochemistry of Nanostructured Intercalation Hosts

    SciTech Connect

    Professor William H. Smyrl, Principal Investigator

    2009-03-09

    We have shown that: (1) Li+ ions are inserted reversibly, without diffusion control, up to the level of at least 4 moles Li+ ions per mole for V2O5, in the aerogel (ARG) form (500 m2/g specific surface area) and aerogel-like (ARG-L) form (200 m2/g specific surface area)(6,7,1,2); (2) polyvalent cations (Al+3, Mg+2, Zn+2) may be intercalated reversibly into V2O5 (ARG) with high capacity (approaching 4 equivalents/mole V2O5 (ARG)) for each (5); (3) dopant cations such as Ag+ and Cu+2 increase the conductivity of V2O5 (XRG) up to three orders of magnitude(3), they are electrochemically active – showing reduction to the metallic-state in parallel to intercalation of Li+ ions – but are not released to the electrolyte upon oxidation and Li+ ion release (Cu+2 ions are reduced to Cu metal and reoxidized to Cu+2 in Li+ ion insertion/release cycles, but the copper ions are not released to the electrolyte over more than 400 cycles of the XRG form); (4) we have shown that Cu+2 ion (dopant) and Zn+2 ions (chemical insertion and dopant) occupy the same intercalation site inV2O5 xerogel and aerogel(4); (5) the reversible intercalation of Zn+2, Mg+2, and Al+3 in the ARG(11) indicates that these cations are “mobile”, but that Cu+2 ions and Ag+ ions are “immobile” in the xerogel, i.e., the latter ions are not exchanged with the electrolyte in Li+ ion intercalation cycling(3).

  10. Multi-layer and multi-component intercalation at the graphene/Ir(111) interface

    NASA Astrophysics Data System (ADS)

    Bazarnik, Maciej; Decker, Régis; Brede, Jens; Wiesendanger, Roland

    2015-09-01

    We present a scanning tunneling microscopy study of Fe and Co intercalated at the graphene-Ir(111) interface. In the case of Fe, we investigate the morphology of the surface with respect to the annealing temperature, which activates the intercalation, and as a function of coverage. By increasing the coverage we show that it is possible to intercalate multilayers at the interface. Finally, we demonstrate that the successive intercalation of Co and Fe for the same sample leads to distinct adjacent intercalation areas.

  11. Dynamics of graphite fiber intercalation: In situ resistivity measurements with a four point probe

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.

    1984-01-01

    The dynamics of ferric chloride intercalation of single graphite fibers were studied, in situ, using a four point dc bridge. Measurements before, during and after the intercalation showed that the intercalation occurred within minutes at 200 C. Changes in fiber resistivity after exposure to air suggested hydration of the graphite intercalation compound. Deintercalation of the ferric chloride was initiated at temperatures in excess of 400 C. cycling the intercalant into and out of the graphite fiber gave no improvements in fiber resistivity. The activation energy of the ferric chloride intercalation reaction was found to be 17 + or - 4 kcal/mol 1 consistent with the concept of a preliminary nucleation step in the intercalation reaction.

  12. Materials discovery through crystal growth

    NASA Astrophysics Data System (ADS)

    zur Loye, Hans-Conrad

    2016-04-01

    The discovery of new materials and associated desirable properties has been a driving force behind chemical innovation for centuries. When we look at some of the many recent technological advances, and how widespread and significant their impact has been, we appreciate how much they have relied on new materials. The increase in hard drive storage capacity due to new giant magneto-resistive materials, the ever-shrinking cell phone due to improved microwave dielectric materials, the enhancement in lithium battery storage capacity due to new intercalation materials, or the improved capacitor due to new ferroelectric materials are all excellent examples. How were these materials discovered? While there is no single answer, in all cases there was a First-Material, the archetype in which the phenomenon was first observed, the one that led to further investigations and the subsequent preparation of improved 2nd or 3rd generation materials. It is this First-Material, the archetype, that was discovered - often via crystal growth.

  13. An advanced model framework for solid electrolyte intercalation batteries.

    PubMed

    Landstorfer, Manuel; Funken, Stefan; Jacob, Timo

    2011-07-28

    Recent developments of solid electrolytes, especially lithium ion conductors, led to all solid state batteries for various applications. In addition, mathematical models sprout for different electrode materials and battery types, but are missing for solid electrolyte cells. We present a mathematical model for ion flux in solid electrolytes, based on non-equilibrium thermodynamics and functional derivatives. Intercalated ion diffusion within the electrodes is further considered, allowing the computation of the ion concentration at the electrode/electrolyte interface. A generalized Frumkin-Butler-Volmer equation describes the kinetics of (de-)intercalation reactions and is here extended to non-blocking electrodes. Using this approach, numerical simulations were carried out to investigate the space charge region at the interface. Finally, discharge simulations were performed to study different limitations of an all solid state battery cell. PMID:21681301

  14. Lithium intercalation behavior of surface modified carbonaceous materials

    SciTech Connect

    Tran, T.D.; Murguia, L.X.; Song, X.; Kinoshita, K.

    1997-07-17

    The surface properties of several well-characterized commercial carbon materials were modified by thermal and chemical treatments. The reversible capacities for lithium intercalation of a sponge green coke and a fuel green coke for lithium intercalation increased by as much as 25% after heat treatment in both reducing (5% H{sub 2}/Ar) and oxidizing (CO{sub 2}) environments. The irreversible capacity loss increased significantly with CO{sub 2} treatment at 800{degrees}C. The trend of larger capacity losses with CO{sub 2} treatment is also observed with a synthetic graphite (SFG6) which was produced by heat treatment at about 3000{degrees}C. Carbon fibers that were first impregnated with LiOH solution followed by reaction with CO{sub 2} to form Li{sub 2}CO{sub 3} tended to show lower irreversible capacity losses.

  15. Multiparameter single-molecule fluorescence measurements of DNA intercalating fluorophores

    NASA Astrophysics Data System (ADS)

    Bowen, Benjamin P.; Enderlein, Jorg; Woodbury, Neal W. T.

    2003-06-01

    Experiments using single-molecules of TOTO-1 intercalated into dsDNA were performed to investigate the DNA sequence dependence on the fluorescence detectable with single-molecule fluorescence spectroscopy. Previous work has shown that there is a difference in the fluorescence lifetime when TOTO-1 is intercalated in poly-AT DNA or in poly-GC DNA. The fluorescence detected from single-molecules in this work for poly-GC and poly-AT DNA showed fluorescence lifetimes of 2.1 and 1.8 nsec, respectively. Analysis of the fluorescence intensity detected from single-molecules of TOTO-1 was performed by fluorescence cross-correlation spectroscopy. TOTO-1 is shown to spend large amounts of time in dark states. These dark states reduce the detectable fluorescence intensity to approximately 10 photons per millisecond on average.

  16. Controlling the photoconductivity: Graphene oxide and polyaniline self assembled intercalation

    SciTech Connect

    Vempati, Sesha; Ozcan, Sefika; Uyar, Tamer

    2015-02-02

    We report on controlling the optoelectronic properties of self-assembled intercalating compound of graphene oxide (GO) and HCl doped polyaniline (PANI). Optical emission and X-ray diffraction studies revealed a secondary doping phenomenon of PANI with –OH and –COOH groups of GO, which essentially arbitrate the intercalation. A control on the polarity and the magnitude of the photoresponse (PR) is harnessed by manipulating the weight ratios of PANI to GO (viz., 1:1.5 and 1:2.2 are abbreviated as PG1.5 and PG2.2, respectively), where ±PR = 100(R{sub Dark} – R{sub UV-Vis})/R{sub Dark} and R corresponds to the resistance of the device in dark or UV-Vis illumination. To be precise, the PR from GO, PANI, PG1.5, and PG2.2 are +34%, −111%, −51%, and +58%, respectively.

  17. DNA Intercalated Psoralen Undergoes Efficient Photoinduced Electron Transfer.

    PubMed

    Fröbel, Sascha; Reiffers, Anna; Torres Ziegenbein, Christian; Gilch, Peter

    2015-04-01

    The interaction of psoralens with DNA has been used for therapeutic and research purposes for decades. Still the photoinduced behavior of psoralens in DNA has never been observed directly. Femtosecond transient absorption spectroscopy is used here to gain direct insight into the photophysics of a DNA-intercalated psoralen (4'-aminomethyl-4,5',8-trimethyl-psoralen (AMT)). Intercalation reduces the excited singlet lifetime of AMT to 4 ps compared with 1400 ps for AMT in water. This singlet quenching prohibits the population of the triplet state that is accessed in free AMT. Instead, a DNA to AMT electron transfer takes place. The resulting radical pair decays primarily via charge recombination with a time constant of 30 ps. The efficient electron transfer observed here reveals a completely new aspect of the psoralen-DNA interaction. PMID:26262984

  18. Graphene on Mica - Intercalated Water Trapped for Life

    PubMed Central

    Ochedowski, O.; Bussmann, B. Kleine; Schleberger, M.

    2014-01-01

    In this work we study the effect of thermal processing of exfoliated graphene on mica with respect to changes in graphene morphology and surface potential. Mild annealing to temperatures of about 200°C leads to the removal of small amounts of intercalated water at graphene edges. By heating to 600°C the areas without intercalated water are substantially increased enabling a quantification of the charge transfer properties of the water layer by locally resolved Kelvin probe force microscopy data. A complete removal on a global scale cannot be achieved because mica begins to decompose at temperatures above 600°C. By correlating Kelvin probe force microscopy and Raman spectroscopy maps we find a transition from p-type to n-type doping of graphene during thermal processing which is driven by the dehydration of the mica substrate and an accumulation of defects in the graphene sheet. PMID:25132493

  19. Tissue tectonics: morphogenetic strain rates, cell shape change and intercalation

    PubMed Central

    Blanchard, Guy B.; Kabla, Alexandre J.; Schultz, Nora L.; Butler, Lucy C.; Sanson, Benedicte; Gorfinkiel, Nicole; Mahadevan, L.; Adams, Richard J.

    2016-01-01

    The dynamic reshaping of tissues during morphogenesis results from a combination of individual cell behaviours and collective cell rearrangements. However, a comprehensive framework to unambiguously measure and link cell behaviour to tissue morphogenesis is lacking. Here we introduce such a kinematic framework, bridging cell and tissue behaviours at an intermediate, mesoscopic, level of cell clusters or domains. By measuring domain deformation in terms of the relative motion of cell positions and the evolution of their shapes, we characterize the basic invariant quantities that measure fundamental classes of cell behaviour, namely tensorial rates of cell shape change and cell intercalation. In doing so we introduce an explicit definition of cell intercalation as a continuous process. We demonstrate how spatiotemporal mapping of strain rates in three models of tissue morphogenesis leads to new insight into morphogenetic mechanisms. Our quantitative approach has broad relevance for the precise characterisation and comparison of morphogenetic phenotypes. PMID:19412170

  20. Sonochemical intercalation of preformed gold nanoparticles into multilayered clays.

    PubMed

    Belova, Valentina; Möhwald, Helmuth; Shchukin, Dmitry G

    2008-09-01

    Multilayered Na (+)-montmorillonite clays intercalated with Au nanoparticles were synthesized by direct ultrasonic impregnation of preformed gold colloid into the clay matrix. The sonicated composite product then consists of Au nanoparticles homogeneously dispersed in the clay. The resulting clay/nano-Au composite was calcined at 800 degrees C and characterized by BET surface area analysis, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared measurements. Nearly spherical-shaped gold nanoparticles, with a size of 6 +/- 0.5 nm, are located in the pores of clay calcined at 800 degrees C. Their nanocomposites are thermally stable as was shown by thermogravimetric analysis. No aggregation of the gold nanoparticles was observed during calcination. The proposed ultrasonic intercalation approach is an universal one and can be employed for synthesis of catalytically active metal-clay nanocomposites stable at high temperatures with high dispersability of the metal nanoparticles in the clay matrix. PMID:18652497

  1. Intercalation of Trichloroethene by Sediment-Associated Clay Minerals

    SciTech Connect

    Matthieu, Donald E.; Brusseau, Mark; Johnson, G. R.; Artiola, J. L.; Bowden, Mark E.; Curry, J. E.

    2013-01-01

    The objective of this research was to examine the potential for intercalation of trichloroethene (TCE) by clay minerals associated with aquifer sediments. Sediment samples were collected from a field site inTucson, AZ. Two widely used Montmorillonite specimen clays were employed as controls. X-ray diffraction, conducted with a controlled-environment chamber, was used to characterize smectite interlayer dspacing for three treatments (bulk air-dry sample, sample mixed with synthetic groundwater, sample mixed with TCE-saturated synthetic groundwater). The results show that the d-spacing measured for the samples treated with TCE-saturated synthetic groundwater are larger (*26%) than those of the untreated samples for all field samples as well as the specimen clays. These results indicate that TCE was intercalated by the clay minerals, which may have contributed to the extensive elution tailing observed in prior miscible-displacement experiments conducted with this sediment.

  2. Controlling the photoconductivity: Graphene oxide and polyaniline self assembled intercalation

    NASA Astrophysics Data System (ADS)

    Vempati, Sesha; Ozcan, Sefika; Uyar, Tamer

    2015-02-01

    We report on controlling the optoelectronic properties of self-assembled intercalating compound of graphene oxide (GO) and HCl doped polyaniline (PANI). Optical emission and X-ray diffraction studies revealed a secondary doping phenomenon of PANI with -OH and -COOH groups of GO, which essentially arbitrate the intercalation. A control on the polarity and the magnitude of the photoresponse (PR) is harnessed by manipulating the weight ratios of PANI to GO (viz., 1:1.5 and 1:2.2 are abbreviated as PG1.5 and PG2.2, respectively), where ±PR = 100(RDark - RUV-Vis)/RDark and R corresponds to the resistance of the device in dark or UV-Vis illumination. To be precise, the PR from GO, PANI, PG1.5, and PG2.2 are +34%, -111%, -51%, and +58%, respectively.

  3. Technological hurdles to the application of intercalated graphite fibers

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1988-01-01

    Before intercalated graphite fibers can be developed as an effective power material, there are several technological hurdles which must be overcome. These include the environmental stability, homogeneity and bulk properties, connection procedures, and costs. Strides were made within the last several years in stability and homogeneity of intercalated graphite fibers. Bulk properties and connection procedures are areas of active research now. Costs are still prohibitive for all but the most demanding applications. None of these problems, however, appear to be unsolvable, and their solution may result in wide spread GOC application. The development of a relatively simple technology application, such as EMI shielding, would stimulate the solution of scale-up problems. Once this technology is developed, then more demanding applications, such as power bus bars, may be possible.

  4. Intercalated graphite fiber composites as EMI shields in aerospace structures

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1990-01-01

    The requirements for electromagnetic interference (EMI) shielding in aerospace structures are complicated over that of ground structures by their weight limitations. As a result, the best EMI shielding materials must blend low density, high strength, and high elastic modulus with high shielding ability. In addition, fabrication considerations including penetrations and joints play a major role. The EMI shielding properties are calculated for shields formed from pristine and intercalated graphite fiber/epoxy composites and compared to preliminary experimental results and to shields made from aluminum. Calculations indicate that EMI shields could be fabricated from intercalated graphite composites which would have less than 12 percent of the mass of conventional aluminum shields, based on mechanical properties and shielding properties alone.

  5. Intercalated graphite fiber composites as EMI shields in aerospace structures

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1992-01-01

    The requirements for electromagnetic interference (EMI) shielding in aerospace structures are more complicated than those for ground structures because of their weight limitations. As a result, the best EMI shielding materials must combine low density, high strength, and high elastic modulus with high shielding ability. EMI shielding characteristics were calculated for shields formed from pristine and intercalated graphite fiber/epoxy composites and compare to preliminary experimental results for these materials and to the characteristics of shields made from aluminum. Calculations indicate that effective EMI shields could be fabricated from intercalated graphite composites which would have less than 12 percent of the mass of conventional aluminum shields, based on mechanical properties and shielding characteristics alone.

  6. Controlled release of donepezil intercalated in smectite clays.

    PubMed

    Park, Jin Kuen; Choy, Young Bin; Oh, Jae-Min; Kim, Ju Young; Hwang, Seong-Ju; Choy, Jin-Ho

    2008-07-01

    The inorganic-organic hybrid for a drug delivery system was successfully realized by intercalating donepezil molecules into smectite clays (laponite XLG, saponite, and montmorillonite). According to the powder XRD patterns, TG profiles, and FT-IR spectra, it was confirmed that donepezil molecules were well stabilized in the interlayer space of clay via mono or double layer stacking. The adsorption amount and molecular structure of donepezil appeared to depend on the cation exchange capacity of the clay, which in turn, tailored the drug release patterns. Especially in the presence of a bulky cationic polymer (Eudragit E-100) in the release media, the release rate was found to be improved due to its effective replacement with intercalated donepezil molecules. Therefore, to formulate a complete drug delivery system, the hybrids were coated with Eudragit E-100 using a spray dryer, which also showed great enhancement in the release rate during a short period of time (180min). PMID:18502063

  7. INTERCALATION OF TRICHLOROETHENE BY SEDIMENT-ASSOCIATED CLAY MINERALS

    PubMed Central

    Matthieu, D.E.; Brusseau, M.L.; Johnson, G.R.; Artiola, J.L.; Bowden, M.L.; Curry, J.E.

    2012-01-01

    The objective of this research was to examine the potential for intercalation of trichloroethene (TCE) by clay minerals associated with aquifer sediments. Sediment samples were collected from a field site in Tucson, AZ. Two widely used Montmorillonite specimen clays were employed as controls. X-ray diffraction, conducted with a controlled-environment chamber, was used to characterize smectite interlayer d-spacing for three treatments (bulk air-dry sample, sample mixed with synthetic groundwater, sample mixed with TCE-saturated synthetic groundwater). The results show that the d-spacing measured for the samples treated with TCE-saturated synthetic groundwater are larger (~26%) than those of the untreated samples for all field samples as well as the specimen clays. These results indicate that TCE was intercalated by the clay minerals, which may have contributed to the extensive elution tailing observed in prior miscible-displacement experiments conducted with this sediment. PMID:22921434

  8. Poly(pyrrole)/MoS{sub 2} intercalation compounds

    SciTech Connect

    Wang, L.; Kanatzidis, M.G.

    1995-12-31

    It is known that polymer/MoS{sub 2} intercalation compounds can be prepared through methods such as polymerizing intercalated monomers in MoS{sub 2} or mixing a polymer solution with MoS{sub 2} single layers suspended in water. The latter method is easy to perform, but can only be applied to soluble polymers. We have developed an in-situ polymerization-encapsulation method which was used to insert poly(pyrrole), an insoluble conjugated polymer, into MoS{sub 2}. Synthesis, characterization and electrical properties of the poly(pyrrole)/MoS{sub 2} materials, prepared by this method, will be presented and compared with other related lamellar systems.

  9. Superconductivity in the Graphite Intercalation Compound BaC 6

    NASA Astrophysics Data System (ADS)

    Heguri, Satoshi; Kawade, Naoya; Fujisawa, Takumi; Yamaguchi, Akira; Sumiyama, Akihiko; Tanigaki, Katsumi; Kobayashi, Mototada

    2015-06-01

    Among many two-dimensional (2D) high TC superconductors, graphite intercalation compounds (GICs) are the most famous intercalation family, which are classified as typical electron-phonon mediated superconductors. We show unambiguous experimental facts that BaC 6 , the superconductivity of which has been missing for many years so far among various alkaline earth metal (Ca, Sr, and Ba) intercalted GICs, exhibits superconductivity at TC=65 mK . By adding this finding as the additional experimental point, a complete figure displaying the relationship between TC and interlayer distance (d ) for GICs is now provided, and their possible superconducting mechanisms raised so far are revisited. The present study settles a long-running debate between theories and experiments on the superconductivity in the first stage GICs.

  10. Graphene Made by Mechanical Exfoliation of Graphite Intercalation Compound

    NASA Astrophysics Data System (ADS)

    Fukada, Seiya; Shintani, Yumi; Shimomura, Midori; Tahara, Fumiya; Yagi, Ryuta

    2012-08-01

    We report a method of making few-layer graphene flakes by mechanically exfoliating SbCl5-graphite intercalation compounds (GICs). The number of layers of exfoliated graphene flakes had a particular distribution relevant to the stage structure of the GICs. The carrier doping of the few-layer graphene flakes was about two orders of magnitude smaller than that expected from the stoichiometry of the GICs. The measured electric mobility was comparable to that made from pristine graphite.

  11. Synthesis, Characterization, and Intercalation of Vanadyl Phosphate Modified with Manganese

    NASA Astrophysics Data System (ADS)

    Richtrová, Klára; Votinský, Jiří; Kalousová, Jaroslava; Beneš, Ludvík.; Zima, Vítěslav

    1995-05-01

    A yellow-brown crystalline solid, stable in air and having a variable composition of [Mn(H 2O] x(VO) 1- xPO 4 · 2H 2O (0 ≤ x ≤ 0.25), has been prepared by the reaction of solid V 2O 5 with a bolling aqueous solution of H 3PO 4 and KMnO 4. The elementary cell of this compound is tetragonal (space symmetry group either P4/ n or P 4/ nmm) with the following parameters for x = 0.25: a = 0.62034 nm, c = 1.3814 nm, V = 0.51359 nm 3, Z = 4, Mr = 199.44, Dcalc = 2.492 g/cm 3, and Dexp = 2.52 g/cm 3. The magnetic behavior of this substance indicates the presence of manganese atoms at the oxidation level of III. The paramagnetic centers formed by the Mn III atoms are not markedly magnetically coupled. The structure of the compound is probably derived from the original layered lattice of vanadyl phosphate hydrate VOPO 4 · 2H 2O by replacement of at most one quarter of the vanadyl groups (V VO) 3+ by [Mn III(H 2O)] 3+ groups. Upon being heated, the substance forms a monohydrate at first, then the anhydrous salt forms, and finally the water coordinated with manganese atoms escapes. The compound can be intercalated with foreign molecules and ions in the same way as vanadyl phosphate, and the results of intercalation experiments with methanol, ethanol, 1-propanol, l-butanol, 1-butylamine, 1-octylamine, formic acid, acetic acid, and pyridine, as well as those of oxidation-reduction intercalation with a solution of sodium iodide in acetone, are presented. The experimental conditions of the intercalations are described. The layered complexes formed have been identified by powder X-ray structure analysis, thermogravimetry, differential thermal analysis, and infrared absorption spectroscopy.

  12. Exfoliation and intercalation of montmorillonite by small peptides

    PubMed Central

    Block, Karin A.; Trusiak, Adrianna; Katz, Al; Alimova, Alexandra; Wei, Hui; Gottlieb, Paul; Steiner, Jeffrey C.

    2015-01-01

    Understanding structural changes in clay minerals induced by complexation with organic matter is relevant to soil science and agricultural applications. In this study, the effect of peptide storage in montmorillonite and the thermal stability of peptide-clay complexes was examined through characterization by X-ray diffraction (XRD), electron microscopy, UV absorption, and thermogravimetric analysis (TGA). XRD analysis of small peptide-montmorillonite clay complexes produced profiles consisting of reflections associated with the smectite 001 reflection and related peaks similar to that produced by a mixed layer clay mineral structure. Shifts in higher order diffraction maxima were attributed to disorder caused by the intercalation with the peptides. Increasing peptide concentrations resulted in greater shifts towards smaller 2θ from 6.37° (1.39 nm) to 5.45° (1.62 nm) as the interlayer space expanded. The expansion was accompanied by broadening of the 001 reflection (FWHM increases from 0.51 to 1.22° 2θ). The XRD line broadening was interpreted as caused by poorer crystallinity resulting from intercalation and tactoid exfoliation. SEM images revealed montmorillonite platelets with upwardly rolled edges that tend toward cylindrical structures with the production of tubules. High-resolution TEM images revealed bending of montmorillonite platelets, confirming exfoliation. The distribution of basal spacings in the micrographs was determined from the spatial frequencies obtained by Fourier analysis of density profiles. The distribution indicated the presence of discrete coherent crystallite domains. XRD and TGA results indicated that higher peptide concentrations resulted in a greater fraction of intercalated peptides and that surface adsorption of peptides mediated intercalation. Therefore, higher peptide concentration led to more stable organoclay complexes. However, UV absorption and TGA found that peptide adsorption onto montmorillonite had a finite limit at

  13. Crystal structures of superconducting sodium intercalates of hafnium nitride chloride

    SciTech Connect

    Oro-Sole, J.; Frontera, C.; Beltran-Porter, D.; Van Tendeloo, G.; Fuertes, A. . E-mail: amparo.fuertes@icmab.es

    2006-05-25

    Sodium intercalation compounds of HfNCl have been prepared at room temperature in naphtyl sodium solutions in tetrahydrofuran and their crystal structure has been investigated by Rietveld refinement using X-ray powder diffraction data and high-resolution electron microscopy. The structure of two intercalates with space group R3-bar m and lattice parameters a=3.58131(6)A, c=57.752(6)A, and a=3.58791(8)A, c=29.6785(17)A is reported, corresponding to the stages 2 and 1, respectively, of Na{sub x}HfNCl. For the stage 2 phase an ordered model is presented, showing two crystallographically independent [HfNCl] units with an alternation of the Hf-Hf interlayer distance along the c-axis, according with the occupation by sodium atoms of one out of two van der Waals gaps. Both stages 1 and 2 phases are superconducting with critical temperatures between 20 and 24K, they coexist in different samples with proportions depending on the synthesis conditions, and show a variation in c spacing that can be correlated with the sodium stoichiometry. High-resolution electron microscopy images of the host and intercalated samples show bending of the HfNCl bilayers as well as stacking faults in some regions, which coexist in the same crystal with ordered domains.

  14. Manipulate the Doping of Graphene at Nanoscale with Intercalated Oxygen

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Luo, Hong; Liu, Lei; Gu, Gong; Stradi, Daniele; Brandbyge, Mads

    2015-03-01

    We have created nanoscale p- and n-doped graphene regions side by side, by partially removing the oxygen between the graphene and the Cu foil growth substrate intercalated upon elongated air exposure. The Cu foil surface is almost exclusively (100) oriented, and the removal of intercalated oxygen is by thermal annealing. Scanning tunneling microscopy (STM) reveals a 0.72 × 0.72 nm square superlattice in the single layer (1L) graphene/O/Cu(100) structure, assigned to be Cu(2√{ 2} × 2√{ 2})R45°-O, which has not been reported so far. Graphene with intercalated oxygen underneath it is p-doped while the surrounding graphene areas, directly in contact with the copper surface, are n-doped. Comparing the scanning tunneling spectra (STS) of the two types of regions, we show a charge transfer-induced shift of the electronic structure. Such a shift is also observed between p- and n-doped twisted bilayer (2L) graphene regions, where the van Hove singularity (vHS) peaks are used as markers to precisely determine the energy shift. Across the boundaries between the p- and n-doped regions, the shift of the electronic structure is spatially resolved, showing the vanishing and reappearance of the vHS peaks. The experimental observations are consistent with first-principles calculations.

  15. Synthesis and characterization of intercalated few-layer graphenes

    NASA Astrophysics Data System (ADS)

    Sato, Shogo; Ichikawa, Hiroaki; Iwata, Nobuyuki; Yamamoto, Hiroshi

    2014-02-01

    Toward achieving room-temperature superconductivity, FeCl3-intercalated few-layer graphenes (FeCl3-FLGs) and Ca-intercalated few-layer graphenes (Ca-FLGs) were synthesized. FeCl3-FLGs were synthesized by the two-zone method and Ca-FLGs were synthesized using Ca-Li alloy. The Raman spectra of the FeCl3-FLGs showed a lower-intensity peak at 1607 cm-1 than that of the corresponding bare G. The peak at 1607 cm-1 suggested that the sample was stage 4-5 FeCl3-FLGs. The room-temperature electrical resistivity of FeCl3-FLGs was 2.65 × 10-5 Ω·m, which linearly decreased with decreasing temperature with a marked change occurring at approximately 200 K. From a XRD pattern of Ca-FLGs, we concluded that Ca is intercalated in FLGs. The room-temperature resistivity of Ca-FLGs was 3.45 × 10-5 Ω·m, which increased with decreasing temperature.

  16. Reversible Intercalation of Fluoride-Anion Receptor Complexes in Graphite

    NASA Technical Reports Server (NTRS)

    West, William C.; Whitacre, Jay F.; Leifer, Nicole; Greenbaum, Steve; Smart, Marshall; Bugga, Ratnakumar; Blanco, Mario; Narayanan, S. R.

    2007-01-01

    We have demonstrated a route to reversibly intercalate fluoride-anion receptor complexes in graphite via a nonaqueous electrochemical process. This approach may find application for a rechargeable lithium-fluoride dual-ion intercalating battery with high specific energy. The cell chemistry presented here uses graphite cathodes with LiF dissolved in a nonaqueous solvent through the aid of anion receptors. Cells have been demonstrated with reversible cathode specific capacity of approximately 80 mAh/g at discharge plateaus of upward of 4.8 V, with graphite staging of the intercalant observed via in situ synchrotron X-ray diffraction during charging. Electrochemical impedance spectroscopy and B-11 nuclear magnetic resonance studies suggest that cointercalation of the anion receptor with the fluoride occurs during charging, which likely limits the cathode specific capacity. The anion receptor type dictates the extent of graphite fluorination, and must be further optimized to realize high theoretical fluorination levels. To find these optimal anion receptors, we have designed an ab initio calculations-based scheme aimed at identifying receptors with favorable fluoride binding and release properties.

  17. Ferric chloride graphite intercalation compounds prepared from graphite fluoride

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    1994-01-01

    The reaction between graphite fluoride and ferric chloride was observed in the temperature range of 300 to 400 C. The graphite fluorides used for this reaction have an sp3 electronic structure and are electrical insulators. They can be made by fluorinating either carbon fibers or powder having various degrees of graphitization. Reaction is fast and spontaneous and can occur in the presence of air. The ferric chloride does not have to be predried. The products have an sp2 electronic structure and are electrical conductors. They contain first stage FeCl3 intercalated graphite. Some of the products contain FeCl2*2H2O, others contain FeF3 in concentrations that depend on the intercalation condition. The graphite intercalated compounds (GIC) deintercalated slowly in air at room temperature, but deintercalated quickly and completely at 370 C. Deintercalation is accompanied by the disappearing of iron halides and the formation of rust (hematite) distributed unevenly on the fiber surface. When heated to 400 C in pure N2 (99.99 vol %), this new GIC deintercalates without losing its molecular structure. However, when the compounds are heated to 800 C in quartz tube, they lost most of its halogen atoms and formed iron oxides (other than hematite), distributed evenly in or on the fiber. This iron-oxide-covered fiber may be useful in making carbon-fiber/ceramic-matrix composites with strong bonding at the fiber-ceramic interface.

  18. Ferrix Chloride-Graphite Intercalation Compounds Prepared From Graphite Flouride

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    1995-01-01

    The reaction between graphite fluoride and ferric chloride was observed in the temperature range of 300 to 400 C. The graphite fluorides used for this reaction have an sp(sup 3) electronic structure and are electrical insulators. They can be made by fluorinating either carbon fibers or powder having various degrees of graphitization. Reaction is fast and spontaneous and can occur in the presence of air. The ferric chloride does not have to be predried. The products have an sp(sup 2) electronic structure and are electrical conductors. They contain first-stage FeCl3 intercalated graphite. Some of the products contain FeCl2 (center dot) 2H2O, others contain FeF3, in concentrations that depend on the intercalation condition. The graphite intercalated compounds (GIC) deintercalated slowly in air at room temperature, but deintercalated quickly and completely at 370 C. Deintercalation is accompanied by the disappearance of iron halides and the formation of rust (hematite) distributed unevenly on the fiber surface. When heated to 400 C in pure N2 (99.99 vol%), this new GIC deintercalates without losing its molecular structure. However, when the compounds are exposed to 800 C N2, in a quartz tube, they lost most of their halogen atoms and formed iron oxides (other than hematite), distributed evenly in or on the fiber.

  19. Electrochemical Intercalation of Lithium Ions into Carbon Nanotube Bundles

    NASA Astrophysics Data System (ADS)

    Allen, J. L.; Sumanasekera, G. U.; Rao, A. M.; Fang, S.; Eklund, P. C.

    1998-03-01

    We have investigated the electrochemical intercalation of lithium ions into ropes of single-walled carbon nanotubes (SWNTs) in a standard three electrode cell. The SWNT mat pressed onto a Pt plate was the working electrode. Lithium was used at both the counter and reference electrodes, and 1M LiAsF6 in ethylene carbonate:diethyl carbonate (1:1 by volume) served as the electrolyte. Raman spectra of the SWNTs were recorded in situ as a function of electrochemical charge using 514.5 nm excitation. During galvanostatic intercalation, we observed a relatively steep decrease in voltage until a plateau at around 1.2 V is reached. We attribute this initial decrease to the intercalation of lithium into SWNT and a concurrent electron doping of the SWNT π band. In the Raman spectrum, as the voltage reaches 1.2 V, the tangential mode frequency down shifted from 1593 cm-1 to 1591 cm-1 consistent with electron addition to the π^* band. We speculate that surface reactions of the lithium doped SWNT and the electrolyte are occuring during the plateau. During the evolution of the plateau, the Raman signal of the tangential mode gradually diminishes without further downshift of the its frequency and eventually disappears completely. Cyclic voltammograms show a minimum at around 1.2 V and peaks at around 0.7 V and 1.7 V. The origin of this structure is not presently understood.

  20. Sodium-Ion Intercalation Mechanism in MXene Nanosheets.

    PubMed

    Kajiyama, Satoshi; Szabova, Lucie; Sodeyama, Keitaro; Iinuma, Hiroki; Morita, Ryohei; Gotoh, Kazuma; Tateyama, Yoshitaka; Okubo, Masashi; Yamada, Atsuo

    2016-03-22

    MXene, a family of layered compounds consisting of nanosheets, is emerging as an electrode material for various electrochemical energy storage devices including supercapacitors, lithium-ion batteries, and sodium-ion batteries. However, the mechanism of its electrochemical reaction is not yet fully understood. Herein, using solid-state (23)Na magic angle spinning NMR and density functional theory calculation, we reveal that MXene Ti3C2Tx in a nonaqueous Na(+) electrolyte exhibits reversible Na(+) intercalation/deintercalation into the interlayer space. Detailed analyses demonstrate that Ti3C2Tx undergoes expansion of the interlayer distance during the first sodiation, whereby desolvated Na(+) is intercalated/deintercalated reversibly. The interlayer distance is maintained during the whole sodiation/desodiation process due to the pillaring effect of trapped Na(+) and the swelling effect of penetrated solvent molecules between the Ti3C2Tx sheets. Since Na(+) intercalation/deintercalation during the electrochemical reaction is not accompanied by any substantial structural change, Ti3C2Tx shows good capacity retention over 100 cycles as well as excellent rate capability. PMID:26891421

  1. Intercalation of stable organic radicals into layered saponite clay.

    PubMed

    Hemme, Wilhelm L; Fujita, Wataru; Awaga, Kunio; Eckert, Hellmut

    2009-10-14

    2-(3- and 4-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-N-oxide (abbreviated as m- and p-MPYNN), the butyl derivative (m- and p-BuPYNN), 4-(N-ethylammonium)-2,2,5,5-tetramethylpiperidin-1-oxyl (ETEP) and N,N,N',N'-Tetramethyl-1,4-phenylenediamine radical cation (TMPD(+)) have been successfully intercalated into saponite clay. The amount of intercalated material has been determined via UV/VIS spectroscopy, elemental analysis and EPR spectroscopy, and the expansion of the layer distance from approximately 12.0 to ca. 15 A has been measured by X-ray powder diffraction. The magnetic properties of these materials, which result from the interplay of the modified intermolecular interactions between the guest species, and the additional interaction with the host lattice, have been characterized by magnetic susceptibility, EPR and solid state NMR measurements. While the (29)Si and (27)Al NMR spectra show little influence of the radical species on the local structural environments of the nuclei in the host lattice, the guest-host interaction manifests itself in significant line-broadening and (in some cases) resonance displacements of the (1)H NMR signals belonging to the molecular radical cations. In the case of TMPD(+) intercalates, the NMR and EPR data indicate predominant radical dimerization within the interlayer space. PMID:19771362

  2. Non-oxidative intercalation and exfoliation of graphite by Brønsted acids

    NASA Astrophysics Data System (ADS)

    Kovtyukhova, Nina I.; Wang, Yuanxi; Berkdemir, Ayse; Cruz-Silva, Rodolfo; Terrones, Mauricio; Crespi, Vincent H.; Mallouk, Thomas E.

    2014-11-01

    Graphite intercalation compounds are formed by inserting guest molecules or ions between sp2-bonded carbon layers. These compounds are interesting as synthetic metals and as precursors to graphene. For many decades it has been thought that graphite intercalation must involve host-guest charge transfer, resulting in partial oxidation, reduction or covalent modification of the graphene sheets. Here, we revisit this concept and show that graphite can be reversibly intercalated by non-oxidizing Brønsted acids (phosphoric, sulfuric, dichloroacetic and alkylsulfonic acids). The products are mixtures of graphite and first-stage intercalation compounds. X-ray photoelectron and vibrational spectra indicate that the graphene layers are not oxidized or reduced in the intercalation process. These observations are supported by density functional theory calculations, which indicate a dipolar interaction between the guest molecules and the polarizable graphene sheets. The intercalated graphites readily exfoliate in dimethylformamide to give suspensions of crystalline single- and few-layer graphene sheets.

  3. Magnetic field effects on superconductivity in alkali metal intercalates of MoS2

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Flood, D. J.; Wagoner, D. E.; Somoano, R. B.; Rembaum, A.

    1972-01-01

    The effects of a magnetic field on the superconducting transition in MoS2 intercalated with potassium and sodium were studied. It was found that the potassium intercalated MoS2 has better properties in a magnetic field. In zero magnetic field the transition to superconductivity begins near 6.4 K. Diagrams of the basic circuitry for superconducting transition studies, and charts showing critical magnetic field versus critical temperature for the intercalated MoS2 are included.

  4. High field superconductivity in alkali metal intercalates of MoS2

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Flood, D. J.; Wagoner, D. E.; Somoano, R. B.; Rembaum, A.

    1973-01-01

    In the search for better high temperature, high critical field superconductors, a class of materials was found which have layered structures and can be intercalated with various elements and compounds. Since a large number of compounds can be formed, intercalation provides a method of control of superconducting properties. They also provide the possible medium for excitonic superconductivity. Results of magnetic field studies are presented on alkali metal (Na, K, Rb, and Cs) intercalated MoS2 (2H polymorph).

  5. Superconductivity in Pd-intercalated charge-density-wave rare earth poly-tellurides RETe n

    NASA Astrophysics Data System (ADS)

    He, J. B.; Wang, P. P.; Yang, H. X.; Long, Y. J.; Zhao, L. X.; Ma, C.; Yang, M.; Wang, D. M.; Shangguan, X. C.; Xue, M. Q.; Zhang, P.; Ren, Z. A.; Li, J. Q.; Liu, W. M.; Chen, G. F.

    2016-06-01

    Charge density waves (CDWs) are periodic modulations of the conduction electron density in solids, which are generally considered to remove electrons from the Fermi level, and thus preclude a superconducting state. However, in a variety of CDW materials, such as the prototypical transition metal chalcogenides, superconductivity has also been observed at very low temperature (Yokoya et al 2001 Science 294 2518; Morosan et al 2006 Nat. Phys. 2 544; Kiss et al 2007 Nat. Phys. 3 720), in which, although the two electronic correlated states are believed to occur in different parts of Fermi surface sheets derived mainly from chalcogen p-states and transition metal d-states, the nature of the relationship between them has not yet been unambiguously determined. Here we report the discovery of superconductivity in Pd-intercalated RETe n (RE = rare earth; n = 2.5, 3) CDW systems, in which the chalcogen layers alone are responsible for both superconductivity and CDW instability. Our finding could provide an ideal model system for comprehensive study of the interplay between CDW and superconductivity due to the remarkable simplicity of the electronic structure of Te planes.

  6. Nickel hexacyanoferrate, a versatile intercalation host for divalent ions from nonaqueous electrolytes

    NASA Astrophysics Data System (ADS)

    Lipson, Albert L.; Han, Sang-Don; Kim, Soojeong; Pan, Baofei; Sa, Niya; Liao, Chen; Fister, Timothy T.; Burrell, Anthony K.; Vaughey, John T.; Ingram, Brian J.

    2016-09-01

    New energy storage chemistries based on Mg ions or Ca ions can theoretically improve both the energy density and reduce the costs of batteries. To date there has been limited progress in implementing these systems due to the challenge of finding a high voltage high capacity cathode that is compatible with an electrolyte that can plate and strip the elemental metal. In order to accelerate the discovery of such a system, model systems are needed that alleviate some of the issues of incompatibility. This report demonstrates the ability of nickel hexacyanoferrate to electrochemically intercalate Mg, Ca and Zn ions from a nonaqueous electrolyte. This material has a relatively high insertion potential and low overpotential in the electrolytes used in this study. Furthermore, since it is not an oxide based cathode it should be able to resist attack by corrosive electrolytes such as the chloride containing electrolytes that are often used to plate and strip magnesium. This makes it an excellent cathode for use in developing and understanding the complex electrochemistry of multivalent ion batteries.

  7. Tuning the properties of polymer bulk heterojunction solar cells by adjusting fullerene size to control intercalation

    SciTech Connect

    Cates, N.C.

    2010-02-24

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells.

  8. Solar flare discovery

    NASA Technical Reports Server (NTRS)

    Hudson, Hugh S.

    1987-01-01

    This paper considers the discoveries that have appreciably changed our understanding of the physics of solar flares. A total of 42 discoveries from all disciplines, ranging from Galileo's initial observation of faculae to the recent discovery of strong limb brightening in 10-MeV gamma-radiation, are identified. The rate of discovery increased dramatically over the past four decades as new observational tools became available. The assessment of significance suggests that recent discoveries -though more numerous - are individually less significant; perhaps this is because the minor early discoveries tend to be taken for granted.

  9. High-Temperature Intercalated Graphite Fiber Conductors Fabricated

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    2002-01-01

    Composites of intercalated graphite fibers show promise to significantly reduce the weight of electromagnetic interference shielding in spacecraft and aircraft. Bromine intercalated pitch-based fibers have been among the most heavily studied systems because of their attractive electrical and thermal conductivities and their stability over a wide range of environmental conditions. Previous studies found that the resistivity of bromineintercalated graphite fibers began to increase when the fibers were exposed to temperatures in excess of about 200 C in air for long periods of time. If the temperature was as high as 450 C, the resistivity increased dramatically within a few hours. It remained unclear, however, whether the increase was due to deintercalation of the bromine or to air oxidation of the fibers. Studies were initially directed toward determining the temperature at which bromine would deintercalate from the fibers, and perhaps become a hazard to both personnel and equipment. So the mass of bromine-intercalated graphite fibers was carefully monitored as it was heated in an inert atmosphere, since the fibers are known to oxidize at a lower temperature than they deintercalate. What was found was that the fibers, which are about 18-wt% bromine, did not lose any appreciable mass even at temperatures approaching 1000 C. X-ray diffraction studies showed that there were also no changes in the overall structure of the compound. Resistivity measurements indicated that there is some slight degradation in the electronic structure, in that the resistivity increased by a few percent. Overall, the results show that these materials may be suitable for applications at temperatures at least this high, provided oxygen is excluded. This may enable their use in carbon-ceramic, and perhaps even carbon-carbon composites.

  10. The intercalated nuclear complex of the primate amygdala.

    PubMed

    Zikopoulos, Basilis; John, Yohan J; García-Cabezas, Miguel Ángel; Bunce, Jamie G; Barbas, Helen

    2016-08-25

    The organization of the inhibitory intercalated cell masses (IM) of the primate amygdala is largely unknown despite their key role in emotional processes. We studied the structural, topographic, neurochemical and intrinsic connectional features of IM neurons in the rhesus monkey brain. We found that the intercalated neurons are not confined to discrete cell clusters, but form a neuronal net that is interposed between the basal nuclei and extends to the dorsally located anterior, central, and medial nuclei of the amygdala. Unlike the IM in rodents, which are prominent in the anterior half of the amygdala, the primate inhibitory net stretched throughout the antero-posterior axis of the amygdala, and was most prominent in the central and posterior extent of the amygdala. There were two morphologic types of intercalated neurons: spiny and aspiny. Spiny neurons were the most abundant; their somata were small or medium size, round or elongated, and their dendritic trees were round or bipolar, depending on location. The aspiny neurons were on average slightly larger and had varicose dendrites with no spines. There were three non-overlapping neurochemical populations of IM neurons, in descending order of abundance: (1) Spiny neurons that were positive for the striatal associated dopamine- and cAMP-regulated phosphoprotein (DARPP-32+); (2) Aspiny neurons that expressed the calcium-binding protein calbindin (CB+); and (3) Aspiny neurons that expressed nitric oxide synthase (NOS+). The unique combinations of structural and neurochemical features of the three classes of IM neurons suggest different physiological properties and function. The three types of IM neurons were intermingled and likely interconnected in distinct ways, and were innervated by intrinsic neurons within the amygdala, or by external sources, in pathways that underlie fear conditioning and anxiety. PMID:27256508

  11. Structural and electronic properties of sodium-intercalated C60

    NASA Astrophysics Data System (ADS)

    Rosseinsky, M. J.; Murphy, D. W.; Fleming, R. M.; Tycko, R.; Ramirez, A. P.; Siegrist, T.; Dabbagh, G.; Barrett, S. E.

    1992-04-01

    The synthesis and initial characterization of bulk Na(x)C60 (x = 2-6) and mixed alkali phase Na2AC60 (where A is K, Rb, or Cs) are reported. All of these phases have intercalated fcc structures. The Na6C60 structure has a Na4 cluster centered on the octahedral site. The Na2AC60 compounds superconduct for the larger A cations, but a crossover to nonsuperconducting behavior occurs with decreasing cation size and correlates with a minimum in the unit cell volume.

  12. Understanding Li diffusion in Li-intercalation compounds.

    PubMed

    Van der Ven, Anton; Bhattacharya, Jishnu; Belak, Anna A

    2013-05-21

    Intercalation compounds, used as electrodes in Li-ion batteries, are a fascinating class of materials that exhibit a wide variety of electronic, crystallographic, thermodynamic, and kinetic properties. With open structures that allow for the easy insertion and removal of Li ions, the properties of these materials strongly depend on the interplay of the host chemistry and crystal structure, the Li concentration, and electrode particle morphology. The large variations in Li concentration within electrodes during each charge and discharge cycle of a Li battery are often accompanied by phase transformations. These transformations include order-disorder transitions, two-phase reactions that require the passage of an interface through the electrode particles, and structural phase transitions, in which the host undergoes a crystallographic change. Although the chemistry of an electrode material determines the voltage range in which it is electrochemically active, the crystal structure of the compound often plays a crucial role in determining the shape of the voltage profile as a function of Li concentration. While the relationship between the voltage profile and crystal structure of transition metal oxide and sulfide intercalation compounds is well characterized, far less is known about the kinetic behavior of these materials. For example, because these processes are especially difficult to isolate experimentally, solid-state Li diffusion, phase transformation mechanisms, and interface reactions remain poorly understood. In this respect, first-principles statistical mechanical approaches can elucidate the effect of chemistry and crystal structure on kinetic properties. In this Account, we review the key factors that govern Li diffusion in intercalation compounds and illustrate how the complexity of Li diffusion mechanisms correlates with the crystal structure of the compound. A variety of important diffusion mechanisms and associated migration barriers are sensitive to

  13. Lithium Intercalation in Core-Shell Materials-Theoretical Analysis

    SciTech Connect

    Suthar, B; Subramanian, VR

    2014-03-04

    Core-shell composite structures are potential candidates for Li-ion battery electrodes as they can take advantage of materials with higher energy density and materials with higher cyclability. This paper derives an analytical solution for isotropic 1-dimensional diffusion with galvanostatic boundary condition in composite slab, cylinder and sphere using separation of variables method. A general interfacial condition has been used to represent the dynamics at the interface of the composite material rendering the solution useful for wide variety of battery materials. Using the derived analytical solution for diffusion, intercalation induced stresses were estimated for spherical core-shell materials. (C) 2014 The Electrochemical Society. All rights reserved.

  14. Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol

    SciTech Connect

    Worcester, D.L.; Hamacher, K.; Kaiser, H.; Kulasekere, R.; Torbet, J.

    1994-12-31

    Partitioning of small hydrophobic molecules into lipid bilayers containing cholesterol has been studied using the 2XC diffractometer at the University of Missouri Research Reactor. Locations of the compounds were determined by Fourier difference methods with data from both deuterated and undeuterated compounds introduced into the bilayers from the vapor phase. Data fitting procedures were developed for determining how well the compounds were localized. The compounds were found to be localized in a narrow region at the center of the hydrophobic layer, between the two halves of the bilayer. The structures are therefore intercalated structures with the long axis of the molecules in the plane of the bilayer.

  15. Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol.

    PubMed

    Worcester, D L; Hamacher, K; Kaiser, H; Kulasekere, R; Torbet, J

    1996-01-01

    Partitioning of small hydrophobic molecules into lipid bilayers containing cholesterol has been studied using the 2XC diffractometer at the University of Missouri Research Reactor. Locations of the compounds were determined by Fourier difference methods with data from both deuterated and undeuterated compounds introduced into the bilayers from the vapor phase. Data fitting procedures were developed for determining how well the compounds were localized. The compounds were found to be localized in a narrow region at the center of the hydrophobic layer, between the two halves of the bilayer. The structures are therefore intercalated structures with the long axis of the molecules in the plane of the bilayer. PMID:9031514

  16. Synthesis, characterization, and intercalation of vanadyl phsophate modified with manganese

    SciTech Connect

    Richtrova, K.; Votinsky, J.; Kalousova, J.

    1995-05-01

    A yellow-brown crystalline solid, stable in air and having a variable composition of [Mn(H{sub 2}O)]{sub x}(VO){sub 1-x}PO{sub 4}{center_dot}2H{sub 2}O (0 {le} x {le} 0.25), has been prepared by the reaction of solid V{sub 2}O{sub 5} with a boiling aqueous solution of H{sub 3}PO{sub 4} and KMnO{sub 4}. The elementary cell of this compound is tetragonal (space symmetry group either P4/n or P4/nmm) with the following parameters for x = 0.25; a = 0.62034 nm, c = 1.3813 nm, V = 0.51359 nm{sup 3}, Z = 4, M{sub r} = 199.44, D{sub calc} = 2.492 g/cm{sup 3}, and D{sub exp} = 2.52 g/cm{sup 3}. The magnetic behavior of this substance indicates the presence of manganese atoms at the oxidation level of III. The paramagnetic centers formed by the Mn{sub III} atoms are not markedly magnetically coupled. The structure of the compound is probably derived from the original layered lattice of vanadyl phosphate hydrate VOPO{sub 4}{center_dot}2H{sub 2}O by replacement of at most one quarter of the vanadyl groups (V{sup V}O){sup 3+} by [Mn{sup III}(H{sub 2}O)]{sup 3+} groups. Upon being heated, the substance forms a monohydrate at first, then the anhydrous salt forms, and finally the water coordinated with manganese atoms escapes. The compound can be intercalated with foreign molecules and ions in the same way as vanadyl phosphate, and the results of intercalation experiments with methanol, ethanol, 1-propanol, 1-butanol, 1-butylamine, 1-octylamine, formic acid, acetic acid, and pyridine, as well as those of oxidation-reduction intercalation with a solution of sodium intercalations are described. The layered complexes formed have been identified by powder X-ray structure analysis, thermogravimetry, differential thermal analysis, and infrared absorption spectroscopy.

  17. C-13 nuclear magnetic resonance in graphite intercalation compounds

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Resing, H. A.

    1985-01-01

    The C-13 NMR chemical shifts of graphite intercalation compounds have been calculated. For acceptor types, the shifts come mainly from the paramagnetic (Ramsey) intra-atomic terms. They are related to the gross features of the two-dimensional band structures. The calculated anisotropy is about - 140 ppm and is independent of the finer details such as charge transfer. For donor types, the carbon 2p pi orbitals are spin-polarized because of mixing with metal-conduction electrons, thus there is an additional dipolar contribution which may be correlated with the electronic specific heat. The general agreement with experimental data is satisfactory.

  18. The 13C nuclear magnetic resonance in graphite intercalation compounds

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Resing, H. A.

    1985-01-01

    The (13)C NMR chemical shifts of graphite intercalation compounds were calculated. For acceptor types, the shifts come mainly from the paramagnetic (Ramsey) intra-atomic terms. They are related to the gross features of the two-dimensional band structures. The calculated anisotropy is about -140 ppm and is independent of the finer details such as charge transfer. For donor types, the carbon 2p pi orbitals are spin-polarized because of mixing with metal conduction electrons, thus there is an additional dipolar contribution which may be correlated with the electronic specific heat. The general agreement with experimental data is satisfactory.

  19. Lithium intercalation reaction into the Keggin type polyoxomolybdates

    NASA Astrophysics Data System (ADS)

    Sonoyama, Noriyuki; Suganuma, Yoshiaki; Kume, Tomohiro; Quan, Zhen

    The electrochemical property of Keggin type hetero polyoxomolybdate K 3[PMo 12O 40] (KPM) as the cathode electrode material for lithium battery was examined. KPM showed charge-discharge performance in the potential region from 4.2 V to 1.5 V with capacity of over 200 mAh g -1. From the result of the ex situ XRD measurement, it is presumed that the electrochemical reaction of KPM proceeds via the lithium (de-)intercalation. The cycle performance of KPM is largely dependent on the charge-discharge potential range. The capacity fade caused by deep discharging seems to be concerned to the < to ® isomerization of KPM.

  20. Microscopic physical and chemical properties of graphite intercalation compounds

    SciTech Connect

    Eklund, P.C.

    1992-08-24

    Optical spectroscopy (Raman, FTIR and Reflection ) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

  1. Electron Beam Irradiated Intercalated CNT Yarns For Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Waters, Deborah L.; Gaier, James R.; Williams, Tiffany S.; Lopez Calero, Johnny E.; Ramirez, Christopher; Meador, Michael A.

    2015-01-01

    Multi-walled CNT yarns have been experimentally and commercially created to yield lightweight, high conductivity fibers with good tensile properties for application as electrical wiring and multifunctional tendons. Multifunctional tendons are needed as the cable structures in tensegrity robots for use in planetary exploration. These lightweight robust tendons can provide mechanical strength for movement of the robot in addition to power distribution and data transmission. In aerospace vehicles, such as Orion, electrical wiring and harnessing mass can approach half of the avionics mass. Use of CNT yarns as electrical power and data cables could reduce mass of the wiring by thirty to seventy percent. These fibers have been intercalated with mixed halogens to increase their specific electrical conductivity to that near copper. This conductivity, combined with the superior strength and fatigue resistance makes it an attractive alternative to copper for wiring and multifunctional tendon applications. Electron beam irradiation has been shown to increase mechanical strength in pristine CNT fibers through increased cross-linking. Both pristine and intercalated CNT yarns have been irradiated using a 5-megavolt electron beam for various durations and the conductivities and tensile properties will be discussed. Structural information obtained using a field emission scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy will correlate microstructural details with bulk properties.

  2. Resistivity of pristine and intercalated graphite fiber epoxy composites

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Hambourger, Paul D.; Slabe, Melissa E.

    1989-01-01

    Laminar composites were fabricated from pristine and bromine intercalated Amoco P-55, P-75, and P-100 graphite fibers and Hysol-Grafil EAG101-1 film epoxy. The thickness and r.f. eddy current resistivity of several samples were measured at grid points and averaged point by point to obtain final values. Although the values obtained this way have high precision (less than 3 percent deviation), the resistivity values appear to be 20 to 90 percent higher than resistivities measured on high aspect ratio samples using multi-point techniques, and by those predicted by theory. The temperature dependence of the resistivity indicates that the fibers are neither damaged nor deintercalated by the composite fabrication process. The resistivity of the composites is a function of sample thickness (i.e., resin content). Composite resistivity is dominated by fiber resistivity, so lowering the resistivity of the fibers, either through increased graphitization or intercalation, results in a lower composite resistivity. A modification of the simple rule of mixtures model appears to predict the conductivity of high aspect ratio samples measured along a fiber direction, but a directional dependence appears which is not predicted by the theory. The resistivity of these materials is clearly more complex than that of homogeneous materials.

  3. NLP-1: a DNA intercalating hypoxic cell radiosensitizer and cytotoxin

    SciTech Connect

    Panicucci, R.; Heal, R.; Laderoute, K.; Cowan, D.; McClelland, R.A.; Rauth, A.M.

    1989-04-01

    The 2-nitroimidazole linked phenanthridine, NLP-1 (5-(3-(2-nitro-1-imidazoyl)-propyl)-phenanthridinium bromide), was synthesized with the rationale of targeting the nitroimidazole to DNA via the phenanthridine ring. The drug is soluble in aqueous solution (greater than 25 mM) and stable at room temperature. It binds to DNA with a binding constant 1/30 that of ethidium bromide. At a concentration of 0.5 mM, NLP-1 is 8 times more toxic to hypoxic than aerobic cells at 37 degrees C. This concentration is 40 times less than the concentration of misonidazole, a non-intercalating 2-nitroimidazole, required for the same degree of hypoxic cell toxicity. The toxicity of NLP-1 is reduced at least 10-fold at 0 degrees C. Its ability to radiosensitize hypoxic cells is similar to misonidazole at 0 degrees C. Thus the putative targeting of the 2-nitroimidazole, NLP-1, to DNA, via its phenanthridine group, enhances its hypoxic toxicity, but not its radiosensitizing ability under the present test conditions. NLP-1 represents a lead compound for intercalating 2-nitroimidazoles with selective toxicity for hypoxic cells.

  4. Methotrexate intercalated ZnAl-layered double hydroxide

    NASA Astrophysics Data System (ADS)

    Chakraborty, Manjusha; Dasgupta, Sudip; Soundrapandian, Chidambaram; Chakraborty, Jui; Ghosh, Swapankumar; Mitra, Manoj K.; Basu, Debabrata

    2011-09-01

    The anticancerous drug methotrexate (MTX) has been intercalated into an ZnAl-layered double hydroxide (LDH) using an anion exchange technique to produce LDH-MTX hybrids having particle sizes in the range of 100-300 nm. X-ray diffraction studies revealed increases in the basal spacings of ZnAl-LDH-MTX hybrid on MTX intercalation. This was corroborated by the transmission electron micrographs, which showed an increase in average interlayer spacing from 8.9 Å in pristine LDH to 21.3 Å in LDH-MTX hybrid. Thermogravimetric analyses showed an increase in the decomposition temperature for the MTX molecule in the LDH-MTX hybrid indicating enhanced thermal stability of the drug molecule in the LDH nanovehicle. The cumulative release profile of MTX from ZnAl-LDH-MTX hybrids in phosphate buffer saline (PBS) at pH 7.4 was successfully sustained for 48 h following Rigter-Peppas model release kinetics via diffusion.

  5. An intercalation-locked parallel-stranded DNA tetraplex

    PubMed Central

    Tripathi, Shailesh; Zhang, Daoning; Paukstelis, Paul J.

    2015-01-01

    DNA has proved to be an excellent material for nanoscale construction because complementary DNA duplexes are programmable and structurally predictable. However, in the absence of Watson–Crick pairings, DNA can be structurally more diverse. Here, we describe the crystal structures of d(ACTCGGATGAT) and the brominated derivative, d(ACBrUCGGABrUGAT). These oligonucleotides form parallel-stranded duplexes with a crystallographically equivalent strand, resulting in the first examples of DNA crystal structures that contains four different symmetric homo base pairs. Two of the parallel-stranded duplexes are coaxially stacked in opposite directions and locked together to form a tetraplex through intercalation of the 5′-most A–A base pairs between adjacent G–G pairs in the partner duplex. The intercalation region is a new type of DNA tertiary structural motif with similarities to the i-motif. 1H–1H nuclear magnetic resonance and native gel electrophoresis confirmed the formation of a parallel-stranded duplex in solution. Finally, we modified specific nucleotide positions and added d(GAY) motifs to oligonucleotides and were readily able to obtain similar crystals. This suggests that this parallel-stranded DNA structure may be useful in the rational design of DNA crystals and nanostructures. PMID:25628357

  6. Intercalation of cellulase enzyme into a hydrotalcite layer structure

    NASA Astrophysics Data System (ADS)

    Zou, N.; Plank, J.

    2015-01-01

    A new inorganic-organic hybrid material whereby cellulase enzyme is incorporated into a hydrotalcite type layered double hydroxide (LDH) structure is reported. The Mg2Al-cellulase-LDH was synthesized via co-precipitation from Mg/Al nitrate at pH=9.6. Characterization was performed using X-ray powder diffraction (XRD), small angle X-ray scattering (SAXS), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). From XRD and SAXS measurements, a d-value of ~5.0 nm was identified for the basal spacing of the Mg2Al-cellulase-LDH. Consequently, the cellulase enzyme (hydrodynamic diameter ~6.6 nm) attains a slightly compressed conformation when intercalated. Formation of the LDH hybrid was also confirmed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mg2Al-cellulase-LDH phases appear as ~20 nm thin foils which are intergrown to flower-like aggregates. Activity of the enzyme was retained after deintercalation from the Mg2Al-LDH framework using anion exchange. Accordingly, cellulase is not denatured during the intercalation process, and LDH presents a suitable host structure for time-controlled release of the biomolecule.

  7. Modeling of alkyl quaternary ammonium cations intercalated into montmorillonite lattice

    SciTech Connect

    Daoudi, El Mehdi; Boughaleb, Yahia; El Gaini, Layla; Meghea, Irina; Bakasse, Mina

    2013-05-15

    Highlights: ► The modification of montmorillonites by three surfactants increases the basal spacing. ► The model proposed show a bilayer conformation for the surfactant ODTMA. ► The DODMA and TOMA surfactants adopt a paraffin type arrangement. ► Behavior of surfactants in interlayer space was confirmed by TGA and ATR analysis. - Abstract: The objective of this work was to study the conformation of the quaternary ammonium cations viz., octadecyl trimethyl ammonium (ODTMA), dioctadecyl dimethyl ammonium (DMDOA) and trioctadecyl methyl ammonium (TOMA) intercalated within montmorillonite. The modified montmorillonite was characterized by X-ray diffraction in small angle (SAXS), thermal analysis (TGA) and infrared spectroscopy of attenuated total reflection (ATR). The modification of organophilic montmorillonites by the three surfactants ODTMA, DMDOA and TOMA increases the basal spacing from their respective intercalated distances of 1.9 nm, 2.6 nm and 3.4 nm respectively. The increase in the spacing due to the basic organic modification was confirmed by the results of thermal analysis (TGA) and infrared spectroscopy (ATR), and also supported by theoretical calculations of longitudinal and transversal chain sizes of these alkyl quaternary ammonium cations.

  8. Two Dimensional Ice crystals intercalated between graphene and mica

    NASA Astrophysics Data System (ADS)

    Bampoulis, Pantelis; Siekman, Martin H.; Kooij, E. Stefan; Lohse, Detlef; Zandvliet, Harold J. W.; Poelsema, Bene; Mesa+ Institute for Nanotechnology Team

    The physics and chemistry of the interfacial contact between water and solid surfaces are of the highest fundamental and practical interest in environmental sciences, many biological systems and corrosion effects. Water intercalated between graphene and mica has recently received much interest, even amplified by intriguing intercalation effects and by the evolution of fractals. These confined water layers are argued to be ice-like at room temperature. Due to its good thermal isolation from the environment, as a result of poor perpendicular heat transport through both mica and graphene, this system is uniquely suited for studying the consequences of heat transport, due to latent heat effects, during growth and melting of 2D ice crystals. The enigmatic growth of ice crystals poses a longstanding fundamental problem and its solution is possibly hidden in influences of heat and particle transport. Indeed, we find that heat and particle transport play a crucial role in the growth of ice crystals under high-temperature and high supersaturation conditions.

  9. Membrane-intercalating conjugated oligoelectrolytes: impact on bioelectrochemical systems.

    PubMed

    Yan, Hengjing; Catania, Chelsea; Bazan, Guillermo C

    2015-05-20

    Conjugated oligoelectrolytes (COEs), molecules that are defined by a π-delocalized backbone and terminal ionic pendant groups, have been previously demonstrated to effectively reduce charge-injection/extraction barriers at metal/organic interfaces in thin-film organic-electronic devices. Recent studies demonstrate a spontaneous affinity of certain COEs to intercalate into, and align within, lipid bilayers in an ordered orientation, thereby allowing modification of membrane properties and the functions of microbes in bioelectrochemical and photosynthetic systems. Several reports have provided evidence of enhanced current generation and bioproduction. Mechanistic approaches suggest that COEs influence microbial extracellular electron transport to abiotic electrode surfaces via more than one proposed pathway, including direct electron transfer and meditated electron transfer. Molecular dynamics simulations as a function of molecular structure suggest that insertion of cationic COEs results in membrane thinning as the lipid phosphate head groups are drawn toward the center of the bilayer. Since variations in molecular structures, especially the length of the conjugated backbone, distribution of ionic groups, and hydrophobic substitutions, show an effect on their antimicrobial properties, preferential cell localization, and microbial selection, it is promising to further design novel membrane-intercalating molecules based on COEs for practical applications, including energy generation, environmental remediation, and antimicrobial treatment. PMID:25846107

  10. An intercalation-locked parallel-stranded DNA tetraplex

    DOE PAGESBeta

    Tripathi, S.; Zhang, D.; Paukstelis, P. J.

    2015-01-27

    DNA has proved to be an excellent material for nanoscale construction because complementary DNA duplexes are programmable and structurally predictable. However, in the absence of Watson–Crick pairings, DNA can be structurally more diverse. Here, we describe the crystal structures of d(ACTCGGATGAT) and the brominated derivative, d(ACBrUCGGABrUGAT). These oligonucleotides form parallel-stranded duplexes with a crystallographically equivalent strand, resulting in the first examples of DNA crystal structures that contains four different symmetric homo base pairs. Two of the parallel-stranded duplexes are coaxially stacked in opposite directions and locked together to form a tetraplex through intercalation of the 5'-most A–A base pairs betweenmore » adjacent G–G pairs in the partner duplex. The intercalation region is a new type of DNA tertiary structural motif with similarities to the i-motif. 1H–1H nuclear magnetic resonance and native gel electrophoresis confirmed the formation of a parallel-stranded duplex in solution. Finally, we modified specific nucleotide positions and added d(GAY) motifs to oligonucleotides and were readily able to obtain similar crystals. This suggests that this parallel-stranded DNA structure may be useful in the rational design of DNA crystals and nanostructures.« less

  11. Anion-Intercalating Cathodes for High-Energy-Density Cells

    NASA Technical Reports Server (NTRS)

    West, William

    2006-01-01

    A report discusses physicochemical issues affecting a fluoride-intercalating cathode that operates in conjunction with a lithium ion-intercalating anode in a rechargeable electrochemical cell described in a cited prior report. The instant report also discusses corresponding innovations made in solvent and electrolyte compositions since the prior report. The advantages of this cell, relative to other lithium-ion-based cells, are said to be greater potential (5 V vs. 4 V), and greater theoretical cathode specific capacity (0.9 to 2.2 A-h/g vs. about 0.18 A-h/g). The discussion addresses a need for the solvent to be unreactive toward the lithium anode and to resist anodic oxidation at potentials greater than about 4.5 V vs. lithium; the pertinent innovation is the selection of propylene carbonate (PC) as a solvent having significantly more stability, relative to other solvents that have been tried. The discussion also addresses the need for an electrolyte additive, denoted an anion receptor, to complex the fluoride ion; the pertinent innovation is the selection of tris(hexafluoroisopropyl) borate as a superior alternative to the prior anion receptor, which was tris(pentafluorophenyl) borate.

  12. Sulfuric Acid Intercalated Graphite Oxide for Graphene Preparation

    NASA Astrophysics Data System (ADS)

    Hong, Yanzhong; Wang, Zhiyong; Jin, Xianbo

    2013-12-01

    Graphene has shown enormous potential for innovation in various research fields. The current chemical approaches based on exfoliation of graphite via graphite oxide (GO) are potential for large-scale synthesis of graphene but suffer from high cost, great operation difficulties, and serious waste discharge. We report a facile preparation of graphene by rapid reduction and expansion exfoliation of sulfuric acid intercalated graphite oxide (SIGO) at temperature just above 100°C in ambient atmosphere, noting that SIGO is easily available as the immediate oxidation descendent of graphite in sulfuric acid. The oxygenic and hydric groups in SIGO are mainly removed through dehydration as catalyzed by the intercalated sulfuric acid (ISA). The resultant consists of mostly single layer graphene sheets with a mean diameter of 1.07 μm after dispersion in DMF. This SIGO process is reductant free, easy operation, low-energy, environmental friendly and generates graphene with low oxygen content, less defect and high conductivity. The provided synthesis route from graphite to graphene via SIGO is compact and readily scalable.

  13. Sulfuric Acid Intercalated Graphite Oxide for Graphene Preparation

    PubMed Central

    Hong, Yanzhong; Wang, Zhiyong; Jin, Xianbo

    2013-01-01

    Graphene has shown enormous potential for innovation in various research fields. The current chemical approaches based on exfoliation of graphite via graphite oxide (GO) are potential for large-scale synthesis of graphene but suffer from high cost, great operation difficulties, and serious waste discharge. We report a facile preparation of graphene by rapid reduction and expansion exfoliation of sulfuric acid intercalated graphite oxide (SIGO) at temperature just above 100°C in ambient atmosphere, noting that SIGO is easily available as the immediate oxidation descendent of graphite in sulfuric acid. The oxygenic and hydric groups in SIGO are mainly removed through dehydration as catalyzed by the intercalated sulfuric acid (ISA). The resultant consists of mostly single layer graphene sheets with a mean diameter of 1.07 μm after dispersion in DMF. This SIGO process is reductant free, easy operation, low-energy, environmental friendly and generates graphene with low oxygen content, less defect and high conductivity. The provided synthesis route from graphite to graphene via SIGO is compact and readily scalable. PMID:24310650

  14. An intercalation-locked parallel-stranded DNA tetraplex

    SciTech Connect

    Tripathi, S.; Zhang, D.; Paukstelis, P. J.

    2015-01-27

    DNA has proved to be an excellent material for nanoscale construction because complementary DNA duplexes are programmable and structurally predictable. However, in the absence of Watson–Crick pairings, DNA can be structurally more diverse. Here, we describe the crystal structures of d(ACTCGGATGAT) and the brominated derivative, d(ACBrUCGGABrUGAT). These oligonucleotides form parallel-stranded duplexes with a crystallographically equivalent strand, resulting in the first examples of DNA crystal structures that contains four different symmetric homo base pairs. Two of the parallel-stranded duplexes are coaxially stacked in opposite directions and locked together to form a tetraplex through intercalation of the 5'-most A–A base pairs between adjacent G–G pairs in the partner duplex. The intercalation region is a new type of DNA tertiary structural motif with similarities to the i-motif. 1H–1H nuclear magnetic resonance and native gel electrophoresis confirmed the formation of a parallel-stranded duplex in solution. Finally, we modified specific nucleotide positions and added d(GAY) motifs to oligonucleotides and were readily able to obtain similar crystals. This suggests that this parallel-stranded DNA structure may be useful in the rational design of DNA crystals and nanostructures.

  15. Duplex-Selective Ruthenium-based DNA Intercalators

    PubMed Central

    Shade, Chad M.; Kennedy, Robert D.; Rouge, Jessica L.; Rosen, Mari S.; Wang, Mary X.; Seo, Soyoung E.; Clingerman, Daniel J.

    2016-01-01

    We report the design and synthesis of small molecules that exhibit enhanced luminescence in the presence of duplex rather than single-stranded DNA. The local environment presented by a well-known [Ru(dipyrido[2,3-a:3',2'-c]phenazine)L2]2+-based DNA intercalator was modified by functionalizing the bipyridine ligands with esters and carboxylic acids. By systematically varying the number and charge of the pendant groups, it was determined that decreasing the electrostatic interaction between the intercalator and the anionic DNA backbone reduced single-strand interactions and translated to better duplex specificity. In studying this class of complexes, a single RuII complex emerged that selectively luminesces in the presence of duplex DNA with little to no background from interacting with single stranded DNA. This complex shows promise as a new dye capable of selectively staining double versus single-stranded DNA in gel electrophoresis, which cannot be done with conventional SYBR dyes. PMID:26119581

  16. Controlled Sequestration of DNA Intercalated Drug by Polymer-Surfactant Supramolecular Assemblies.

    PubMed

    Mora, Aruna K; Singh, Prabhat K; Nath, Sukhendu

    2016-05-01

    Triblock copolymer and surfactant based supramolecular assemblies have been used for the controlled sequestration of the DNA intercalator. The triblock copolymer micelles do not affect the molecules that are intercalated in the DNA. However, on addition of charged surfactant to the triblock copolymer micellar solution, sequestration of the intercalated molecules from DNA to the polymer-surfactant supramolecular assemblies takes place. Such sequestration of the intercalated molecules in the polymer-surfactant supramolecular assemblies has been explained on the basis of the charged surface formed in the polymer micelles due to the addition of surfactants. Sequestration of the intercalated molecules from the DNA to the polymer-surfactant supramolecular assemblies has been monitored through the ground state absorption, steady state, and time-resolved emission measurements. It is shown that the extent of sequestration of the intercalated molecules can be finely tuned by tuning the concentration of the surfactant in the triblock copolymer solution. Quantitative sequestration of the intercalated molecules by the supramolecular assemblies has been achieved. Such controlled sequestration of the DNA intercalated molecules by polymer-surfactant supramolecular assemblies can be used to study the binding of drug with DNA and may be useful in applications like detoxification in the case of drug overdose. PMID:27077791

  17. Melamine/Stearic Acid Composite Nanowires and Vesicles with an Intercalated Nanostructure Prepared through NCCM Method

    NASA Astrophysics Data System (ADS)

    Guo, Juan; Chen, Dao-yong

    2012-12-01

    A solvent-non-solvent method invented in our laboratory for preparing non-covalently connected micelles (NCCM) was used to intercalate melamine (MA) molecules into stearic acid (SA) bilayers to form the composite nanoparticles with an intercalated nanostructure in which a melamine bilayer is sandwiched between two stearic acid bilayers, NCCM method helps to sufficiently mix the two components in nanospace and meanwhile inhibits the strong tendency of self-crystallization of MA, leading to the intercalation. Although the nanoparticles have a regular inner structure, the primary MA/SA nanoparticles have an irregular morphology. Regular nanoparticles were obtained through annealing the suspension of the primary nanoparticles. Through annealing at different temperatures, the MA/SA composite nanowires and vesicles with an intercalated structure were prepared respectively. It is proposed that the morphological change results from the change in the intercalated structure.

  18. Adsorption and intercalation of Cs atoms on epitaxial graphene on Ir(111)

    NASA Astrophysics Data System (ADS)

    Lazic, Predrag; Petrovic, Marin; Srut, Iva; Pletikosic, Ivo; Milun, Milorad; Pervan, Petar; Runte, Sven; Busse, Carsten; Michely, Thomas; Sokcevic, Damir; Brako, Radovan; Atodiresei, Nicolae; Sadowski, Jurek; Pan, Zhi-Hu; Valla, Tonica; Kralj, Marko

    2013-03-01

    From the experimental studies of surface adsorption of Cs atoms and their intercalation under epitaxial graphene on Ir(111) it is known that both - adsorbed and intercalated phase of Cs atoms coexist. However, adsorbed phase is realized as a diluted superlattice adlayer of Cs atom while intercalated phase is a dense Cs layer. The preference for intercalated phase at large Cs layer densities can not be obtained from the DFT calculations with semilocal (GGA) functionals. Only after the van der Waals interaction is taken into account the agreement with experiment is achieved. From the results of calculations it follows that the main energy contribution responsible for the switching of preference from adsorption to intercalation is the graphene delamination energy from the Ir(111) surface which is dominantly of the van der Waals nature.

  19. Dual Element Intercalation into 2D Layered Bi₂Se₃ Nanoribbons.

    PubMed

    Chen, Karen P; Chung, Frank R; Wang, Mengjing; Koski, Kristie J

    2015-04-29

    We demonstrate the intercalation of multiple zero-valent atomic species into two-dimensional (2D) layered Bi2Se3 nanoribbons. Intercalation is performed chemically through a stepwise combination of disproportionation redox reactions, hydrazine reduction, or carbonyl decomposition. Traditional intercalation is electrochemical thus limiting intercalant guests to a single atomic species. We show that multiple zero-valent atoms can be intercalated through this chemical route into the host lattice of a 2D crystal. Intermetallic species exhibit unique structural ordering demonstrated in a variety of superlattice diffraction patterns. We believe this method is general and can be used to achieve a wide variety of new 2D materials previously inaccessible. PMID:25851420

  20. Transient analysis of intercalation electrodes for parameter estimation

    NASA Astrophysics Data System (ADS)

    Devan, Sheba

    An essential part of integrating batteries as power sources in any application, be it a large scale automotive application or a small scale portable application, is an efficient Battery Management System (BMS). The combination of a battery with the microprocessor based BMS (called "smart battery") helps prolong the life of the battery by operating in the optimal regime and provides accurate information regarding the battery to the end user. The main purposes of BMS are cell protection, monitoring and control, and communication between different components. These purposes are fulfilled by tracking the change in the parameters of the intercalation electrodes in the batteries. Consequently, the functions of the BMS should be prompt, which requires the methodology of extracting the parameters to be efficient in time. The traditional transient techniques applied so far may not be suitable due to reasons such as the inability to apply these techniques when the battery is under operation, long experimental time, etc. The primary aim of this research work is to design a fast, accurate and reliable technique that can be used to extract parameter values of the intercalation electrodes. A methodology based on analysis of the short time response to a sinusoidal input perturbation, in the time domain is demonstrated using a porous electrode model for an intercalation electrode. It is shown that the parameters associated with the interfacial processes occurring in the electrode can be determined rapidly, within a few milliseconds, by measuring the response in the transient region. The short time analysis in the time domain is then extended to a single particle model that involves bulk diffusion in the solid phase in addition to interfacial processes. A systematic procedure for sequential parameter estimation using sensitivity analysis is described. Further, the short time response and the input perturbation are transformed into the frequency domain using Fast Fourier Transform

  1. Copper-Intercalated Birnessite as a Water Oxidation Catalyst.

    PubMed

    Thenuwara, Akila C; Shumlas, Samantha L; Attanayake, Nuwan H; Cerkez, Elizabeth B; McKendry, Ian G; Frazer, Laszlo; Borguet, Eric; Kang, Qing; Zdilla, Michael J; Sun, Jianwei; Strongin, Daniel R

    2015-11-24

    We report a synthetic method to increase the catalytic activity of birnessite toward water oxidation by intercalating copper in the interlayer region of the layered manganese oxide. Intercalation of copper, verified by XRD, XPS, ICP, and Raman spectroscopy, was accomplished by exposing a suspension of birnessite to a Cu(+)-bearing precursor molecule that underwent disproportionation in solution to yield Cu(0) and Cu(2+). Electrocatalytic studies showed that the Cu-modified birnessite exhibited an overpotential for water oxidation of ∼490 mV (at 10 mA/cm(2)) and a Tafel slope of 126 mV/decade compared to ∼700 mV (at 10 mA/cm(2)) and 240 mV/decade, respectively, for birnessite without copper. Impedance spectroscopy results suggested that the charge transfer resistivity of the Cu-modified sample was significantly lower than Cu-free birnessite, suggesting that Cu in the interlayer increased the conductivity of birnessite leading to an enhancement of water oxidation kinetics. Density functional theory calculations show that the intercalation of Cu(0) into a layered MnO2 model structure led to a change of the electronic properties of the material from a semiconductor to a metallic-like structure. This conclusion from computation is in general agreement with the aforementioned impedance spectroscopy results. X-ray photoelectron spectroscopy (XPS) showed that Cu(0) coexisted with Cu(2+) in the prepared Cu-modified birnessite. Control experiments using birnessite that was decorated with only Cu(2+) showed a reduction in water oxidation kinetics, further emphasizing the importance of Cu(0) for the increased activity of birnessite. The introduction of Cu(0) into the birnessite structure also increased the stability of the electrocatalyst. At a working current of 2 mA, the Cu-modified birnessite took ∼3 times longer for the overpotential for water oxdiation to increase by 100 mV compared to when Cu was not present in the birnessite. PMID:26477450

  2. Dry synthesis of lithium intercalated graphite powders and carbon fibers

    SciTech Connect

    Sacci, Robert L; Adamczyk, Leslie A; Veith, Gabriel M; Dudney, Nancy J

    2014-01-01

    Herein we describe the direct synthesis of lithium intercalated graphite by heating under vacuum or ball milling under pressurized Ar(g). Both methods allow for stoichometric control of Li-C ratio in batter-grade graphites and carbon fibers prior formation of a solid electrolyte interphase. The products' surface chemistries, as probed by XPS, suggest that LiC6 are extremely reactive with trace amounts of moisture or oxygen. The open circuit potential and SEM data show that the reactivity of the lithiated battery-grade graphite and the carbon fiber can be related to the density of edge/defect sites on the surfaces. Preliminary results of spontaneous SEI formation on Li-graphite in electrolyte are also given.

  3. Dielectric properties of halloysite and halloysite-formamide intercalate

    NASA Astrophysics Data System (ADS)

    Adamczyk, M.; Rok, M.; Wolny, A.; Orzechowski, K.

    2014-01-01

    Due to a high increase in electromagnetic pollution, the protection from non-ionizing electromagnetic radiation (EMR) represents an important problem of contemporary environmental science. We are searching for natural materials with the potential for EMR screening. We have discovered that hydro-halloysite has interesting properties as an EMR absorber. Unfortunately, it is a very unstable material. Drying it for even a short period of time leads to the loss of desired properties. In the paper, we have demonstrated that the intercalation of halloysite (the process of introducing guest molecules into the mineral structure) makes it possible to recover the ability to absorb an electromagnetic wave and obtain a promising material for electromagnetic field shielding applications.

  4. Intercalation of graphene on iridium with samarium atoms

    NASA Astrophysics Data System (ADS)

    Afanas'eva, E. Yu.; Rut'kov, E. V.; Gall, N. R.

    2016-07-01

    Intercalation of graphene on Ir (111) with Sm atoms is studied by methods of thermal desorption spectroscopy and thermionic emission. It is shown that adsorption of samarium at T = 300 K on graphene to concentrations of N ≤ 6 × 1014 atoms cm-2 followed by heating of the substrate leads to practically complete escape of adsorbate underneath the graphene layer. At N > 6 × 1014 atoms cm-2 and increasing temperature, a fraction of adsorbate remains on graphene in the form of two-dimensional "gas" and samarium islands and are desorbed in the range of temperatures of 1000-1200 K. Samarium remaining under the graphene is desorbed from the surface in the temperature range 1200-2150 K. Model conceptions for the samarium-graphene-iridium system in a wide temperature range are developed.

  5. Morphology and Structure of Amino-fatty Acid Intercalated Montmorillonite

    NASA Astrophysics Data System (ADS)

    Reyes, Larry; Sumera, Florentino

    2015-04-01

    Natural clays and its modified forms have been studied for their wide range of applications, including polymer-layered silicate, catalysts and adsorbents. For nanocomposite production, montmorillonite (MMT) clays are often modified with organic surfactants to favor its intermixing with the polymer matrix. In the present study, Na+-montmorillonite (Na+-MMT) was subjected to organo-modification with a protonated 12-aminolauric acid (12-ALA). The amount of amino fatty acid surfactants loaded was 25, 50, 100 and 200% the cation exchange capacity (CEC) of Na+-MMT (25CEC-AMMT, 50CEC-AMMT, 100CEC-AMMT and 200CEC-AMMT). Fatty acid-derived surfactants are an attractive resource of intercalating agents for clays due to their renewability and abundance. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to determine the occurrence of intercalation of 12-ALA and their molecular structure in the clay's silicates. XRD analysis revealed that the interlayer spacing between the alumino-silicate layers increased from 1.25 nm to 1.82 nm with increasing ALA content. The amino fatty acid chains were considered to be in a flat monolayer structure at low surfactant loading, and a bilayered to a pseudotrilayered structure at high surfactant loading. On the other hand, FTIR revealed that the alkyl chains adopt a gauche conformation, indicating their disordered state based on their CH2symmetric and asymmetric vibrations. Thermogravimetric analyses (TGA) allows the determination of the moisture and organic content in clays. Here, TGA revealed that the surfactant in the clay was thermally stable, with Td ranging from 353° C to 417° C. The difference in the melting behavior of the pristine amino fatty acids and confined fatty acids in the interlayer galleries of the clay were evaluated by Differential Scanning Calorimerty (DSC). The melting temperatures (Tm) of the amino fatty acid in the clay were initially found to be higher than those of the free

  6. Dielectric properties of halloysite and halloysite-formamide intercalate

    SciTech Connect

    Adamczyk, M. Rok, M.; Wolny, A.; Orzechowski, K.

    2014-01-14

    Due to a high increase in electromagnetic pollution, the protection from non-ionizing electromagnetic radiation (EMR) represents an important problem of contemporary environmental science. We are searching for natural materials with the potential for EMR screening. We have discovered that hydro-halloysite has interesting properties as an EMR absorber. Unfortunately, it is a very unstable material. Drying it for even a short period of time leads to the loss of desired properties. In the paper, we have demonstrated that the intercalation of halloysite (the process of introducing guest molecules into the mineral structure) makes it possible to recover the ability to absorb an electromagnetic wave and obtain a promising material for electromagnetic field shielding applications.

  7. Water Intercalation for Seamless, Electrically Insulating, and Thermally Transparent Interfaces.

    PubMed

    Wang, Yanlei; Xu, Zhiping

    2016-01-27

    The interface between functional nanostructures and host substrates is of pivotal importance in the design of their nanoelectronic applications because it conveys energy and information between the device and environment. We report here an interface-engineering approach to establish a seamless, electrically insulating, while thermally transparent interface between graphene and metal substrates by introducing water intercalation. Molecular dynamics simulations and first-principles calculations are performed to demonstrate this concept of design, showing that the presence of the interfacial water layer helps to unfold wrinkles formed in the graphene membrane, insulate the electronic coupling between graphene and the substrate, and elevate the interfacial thermal conductance. The findings here lay the ground for a new class of nanoelectronic setups through interface engineering, which could lead to significant improvement in the performance of nanodevices, such as the field-effect transistors. PMID:26720217

  8. Many electron correlations in stage-1 graphene intercalation compounds

    SciTech Connect

    Acharya, Sidharth Sharma, Raman

    2015-05-15

    Many electron correlations in stage-1 graphene intercalation compounds (GICs) are studied in generalized-random-phase-approximation. With this approximation, we are able to study short range exchange and correlation effects in GICs. These exchange correlations leads to BCS superconducting states in which one electron correlates with another via its correlation hole to form a stable pair of electrons known as Cooper pair. Cooper pair energies are calculated as the excitations in S(q,ω) following a method similar to exciton energy calculations. Short range effects governing local field correction G(q,ω) are studied for all wave vectors and frequencies. We have found a reasonable agreement between our results and the earlier theoretical results.

  9. Gas insulated transmission line having low inductance intercalated sheath

    DOEpatents

    Cookson, Alan H.

    1978-01-01

    A gas insulated transmission line including an outer sheath, an inner conductor disposed within the outer sheath, and an insulating gas between the inner conductor and the outer sheath. The outer sheath comprises an insulating tube having first and second ends, and having interior and exterior surfaces. A first electrically conducting foil is secured to the interior surface of the insulating tube, is spirally wound from one tube end to the second tube end, and has a plurality of overlapping turns. A second electrically conducting foil is secured to the exterior surface of the insulating tube, and is spirally wound in the opposite direction from the first electrically conducting foil. By winding the foils in opposite directions, the inductances within the intercalated sheath will cancel each other out.

  10. An enhanced hydrogen adsorption enthalpy for fluoride intercalated graphite compounds.

    PubMed

    Cheng, Hansong; Sha, Xianwei; Chen, Liang; Cooper, Alan C; Foo, Maw-Lin; Lau, Garret C; Bailey, Wade H; Pez, Guido P

    2009-12-16

    We present a combined theoretical and experimental study on H(2) physisorption in partially fluorinated graphite. This material, first predicted computationally using ab initio molecular dynamics simulation and subsequently synthesized and characterized experimentally, represents a novel class of "acceptor type" graphite intercalated compounds that exhibit significantly higher isosteric heat of adsorption for H(2) at near ambient temperatures than previously demonstrated for commonly available porous carbon-based materials. The unusually strong interaction arises from the semi-ionic nature of the C-F bonds. Although a high H(2) storage capacity (>4 wt %) at room temperature is predicted not to be feasible due to the low heat of adsorption, enhanced storage properties can be envisaged by doping the graphitic host with appropriate species to promote higher levels of charge transfer from graphene to F(-) anions. PMID:19928879

  11. STS-92 Discovery Launch

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Viewed from across the waters of Banana Creek, clouds of smoke and steam are illuminated by the flames from Space Shuttle Discovery'''s perfect on-time launch at 7:17 p.m. EDT. Discovery carries a crew of seven on a construction flight to the International Space Station. Discovery also carries a payload that includes the Integrated Truss Structure Z-1, first of 10 trusses that will form the backbone of the Space Station, and the third Pressurized Mating Adapter that will provide a Shuttle docking port for solar array installation on the sixth Station flight and Lab installation on the seventh Station flight. Discovery'''s landing is expected Oct. 22 at 2:10 p.m. EDT.

  12. Computational drug discovery

    PubMed Central

    Ou-Yang, Si-sheng; Lu, Jun-yan; Kong, Xiang-qian; Liang, Zhong-jie; Luo, Cheng; Jiang, Hualiang

    2012-01-01

    Computational drug discovery is an effective strategy for accelerating and economizing drug discovery and development process. Because of the dramatic increase in the availability of biological macromolecule and small molecule information, the applicability of computational drug discovery has been extended and broadly applied to nearly every stage in the drug discovery and development workflow, including target identification and validation, lead discovery and optimization and preclinical tests. Over the past decades, computational drug discovery methods such as molecular docking, pharmacophore modeling and mapping, de novo design, molecular similarity calculation and sequence-based virtual screening have been greatly improved. In this review, we present an overview of these important computational methods, platforms and successful applications in this field. PMID:22922346

  13. Advantages of GPU technology in DFT calculations of intercalated graphene

    NASA Astrophysics Data System (ADS)

    Pešić, J.; Gajić, R.

    2014-09-01

    Over the past few years, the expansion of general-purpose graphic-processing unit (GPGPU) technology has had a great impact on computational science. GPGPU is the utilization of a graphics-processing unit (GPU) to perform calculations in applications usually handled by the central processing unit (CPU). Use of GPGPUs as a way to increase computational power in the material sciences has significantly decreased computational costs in already highly demanding calculations. A level of the acceleration and parallelization depends on the problem itself. Some problems can benefit from GPU acceleration and parallelization, such as the finite-difference time-domain algorithm (FTDT) and density-functional theory (DFT), while others cannot take advantage of these modern technologies. A number of GPU-supported applications had emerged in the past several years (www.nvidia.com/object/gpu-applications.html). Quantum Espresso (QE) is reported as an integrated suite of open source computer codes for electronic-structure calculations and materials modeling at the nano-scale. It is based on DFT, the use of a plane-waves basis and a pseudopotential approach. Since the QE 5.0 version, it has been implemented as a plug-in component for standard QE packages that allows exploiting the capabilities of Nvidia GPU graphic cards (www.qe-forge.org/gf/proj). In this study, we have examined the impact of the usage of GPU acceleration and parallelization on the numerical performance of DFT calculations. Graphene has been attracting attention worldwide and has already shown some remarkable properties. We have studied an intercalated graphene, using the QE package PHonon, which employs GPU. The term ‘intercalation’ refers to a process whereby foreign adatoms are inserted onto a graphene lattice. In addition, by intercalating different atoms between graphene layers, it is possible to tune their physical properties. Our experiments have shown there are benefits from using GPUs, and we reached an

  14. Single-molecule kinetics and footprinting of DNA bis-intercalation: the paradigmatic case of Thiocoraline.

    PubMed

    Camunas-Soler, Joan; Manosas, Maria; Frutos, Silvia; Tulla-Puche, Judit; Albericio, Fernando; Ritort, Felix

    2015-03-11

    DNA bis-intercalators are widely used in molecular biology with applications ranging from DNA imaging to anticancer pharmacology. Two fundamental aspects of these ligands are the lifetime of the bis-intercalated complexes and their sequence selectivity. Here, we perform single-molecule optical tweezers experiments with the peptide Thiocoraline showing, for the first time, that bis-intercalation is driven by a very slow off-rate that steeply decreases with applied force. This feature reveals the existence of a long-lived (minutes) mono-intercalated intermediate that contributes to the extremely long lifetime of the complex (hours). We further exploit this particularly slow kinetics to determine the thermodynamics of binding and persistence length of bis-intercalated DNA for a given fraction of bound ligand, a measurement inaccessible in previous studies of faster intercalating agents. We also develop a novel single-molecule footprinting technique based on DNA unzipping and determine the preferred binding sites of Thiocoraline with one base-pair resolution. This fast and radiolabelling-free footprinting technique provides direct access to the binding sites of small ligands to nucleic acids without the need of cleavage agents. Overall, our results provide new insights into the binding pathway of bis-intercalators and the reported selectivity might be of relevance for this and other anticancer drugs interfering with DNA replication and transcription in carcinogenic cell lines. PMID:25690887

  15. Thermodynamic Complexing of Monocyclopentadienylferrum (II) Intercalates with Double-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Mykhailenko, O. V.; Prylutskyy, Yu I.; Komarov, I. V.; Strungar, A. V.

    2016-03-01

    By employing the methods of molecular mechanics, semi-empirical quantum-chemical PM3 and Monte-Carlo, the positioning of monocyclopentadienylferrum (II) molecules in double-walled (5,5)@(10,10) carbon nanotubes (CNT) depending on their concentration and temperature has been studied. The molecules have been found out to form stable bonds with CNT walls, with a tendency between intercalate stability and the CNT structure. The temperature growth (over ~500 K) causes gradual bond ruining followed by extrusion of interwall intercalate. Further temperature increase up to 600-700 K is characterised with intercalate external surface desorption, stabilising the whole system and keeping the interwall intercalate only. The CNT's UV-spectrum (5,5)@(10,10) depending on the intercalate concentration and association constant of the "double-walled CNT-intercalate" system have been calculated. A combination of unique optical, electrical and magnetic behaviour of cyclopentadienyl complexes with their ability to form high-stable intercalate with CNT opens a prospect of their applying in nanotechnology.

  16. Fabrication and Resistivity of IBr Intercalated Vapor-Grown Carbon Fiber Composites

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Smith, Jaclyn M.; Gahl, Gregory K.; Stevens, Eric C.; Gaier, Elizabeth M.

    1998-01-01

    Composites using vapor-crown carbon fibers (VGCF), the most conductive of the carbon fiber types, are attractive for applications where low density, high strength, and at least moderate conductivity are required, such as electromagnetic interference shielding covers for spacecraft. The conductivity can be enhanced another order of magnitude by intercalation of the VGCF. If a high Z intercalate is used, the protection of components from ionizing radiation can be enhanced also. Thus, the intercalation of VGCF with IBr is reported. Since composite testing is required to verify properties, the intercalation reaction optimization, stability of the intercalation compound, scale-up of the intercalation reaction, composite fabrication, and resistivity of the resulting composites is also reported. The optimum conditions for low resistivity and uniformity for the scaled up reaction (20-30 g of product) were 114 C for at least 72 hr, yielding a fiber with a resistivity of 8.7+/-2 micro-Omega-cm. The thermal stability of these fibers was poor, with degradation occurring at temperatures as low as 40 C in air, though they were insensitive to water vapor. Composite resistivity was 20-30 micro-Omega-cm, as measured by contactless conductivity measurements, about a factor of five higher than would be expected from a simple rule of mixtures. The addition of 1.0 percent Br2, intercalated microfibers increased the resistivity of the composites by more than 20 percent.

  17. Carbon dioxide intercalation in Na-fluorohectorite clay at near-ambient conditions

    NASA Astrophysics Data System (ADS)

    Fossum, Jon Otto; Hemmen, Henrik; Rolseth, Erlend G.; Fonseca, Davi; Lindbo Hansen, Elisabeth; Plivelic, Tomas

    2012-02-01

    A molecular dynamics study by Cygan et al.[1] shows the possibility of intercalation and retention of CO2 in smectite clays at 37 ^oC and 200 bar, which suggests that clay minerals may prove suitable for carbon capture and carbon dioxide sequestration. In this work we show from x-ray diffraction measurements that gaseous CO2 intercalates into the interlayer space of the synthetic smectite clay Na-fluorohectorite. The mean interlayer distance of the clay when CO2 is intercalated is 12.5 å at -20 C and 15 bar. The magnitude of the expansion of the interlayer upon intercalation is indistinguishable from that of the dehydrated-monohydrated intercalation of H2O, but this possibility is ruled out by careful repeating the measurements exposing the clay to nitrogen gas. The dynamics of the CO2 intercalation process displays a higher intercalation rate at increased pressure, and the rate is several orders of magnitude slower than that of water or vapor at ambient pressure and temperature.[4pt] [1] Cygan, R. T.; Romanov, V. N.; Myshakin, E. M. Natural materials for carbon capture; Techincal report SAND2010-7217; Sandia National Laboratories: Albuquerque, New Mexico, November, 2010.

  18. Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

    SciTech Connect

    Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de; Mercante, Luiza A.; Soriano, Stéphane; Andruh, Marius; Vieira, Méri D.; Vaz, Maria G.F.

    2015-08-15

    In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar space of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.

  19. Single-molecule kinetics and footprinting of DNA bis-intercalation: the paradigmatic case of Thiocoraline

    PubMed Central

    Camunas-Soler, Joan; Manosas, Maria; Frutos, Silvia; Tulla-Puche, Judit; Albericio, Fernando; Ritort, Felix

    2015-01-01

    DNA bis-intercalators are widely used in molecular biology with applications ranging from DNA imaging to anticancer pharmacology. Two fundamental aspects of these ligands are the lifetime of the bis-intercalated complexes and their sequence selectivity. Here, we perform single-molecule optical tweezers experiments with the peptide Thiocoraline showing, for the first time, that bis-intercalation is driven by a very slow off-rate that steeply decreases with applied force. This feature reveals the existence of a long-lived (minutes) mono-intercalated intermediate that contributes to the extremely long lifetime of the complex (hours). We further exploit this particularly slow kinetics to determine the thermodynamics of binding and persistence length of bis-intercalated DNA for a given fraction of bound ligand, a measurement inaccessible in previous studies of faster intercalating agents. We also develop a novel single-molecule footprinting technique based on DNA unzipping and determine the preferred binding sites of Thiocoraline with one base-pair resolution. This fast and radiolabelling-free footprinting technique provides direct access to the binding sites of small ligands to nucleic acids without the need of cleavage agents. Overall, our results provide new insights into the binding pathway of bis-intercalators and the reported selectivity might be of relevance for this and other anticancer drugs interfering with DNA replication and transcription in carcinogenic cell lines. PMID:25690887

  20. Thermodynamic Complexing of Monocyclopentadienylferrum (II) Intercalates with Double-Walled Carbon Nanotubes.

    PubMed

    Мykhailenko, О V; Prylutskyy, Yu I; Кomarov, І V; Strungar, А V

    2016-12-01

    By employing the methods of molecular mechanics, semi-empirical quantum-chemical РМ3 and Monte-Carlo, the positioning of monocyclopentadienylferrum (II) molecules in double-walled (5,5)@(10,10) carbon nanotubes (CNT) depending on their concentration and temperature has been studied. The molecules have been found out to form stable bonds with CNT walls, with a tendency between intercalate stability and the CNT structure. The temperature growth (over ~500 K) causes gradual bond ruining followed by extrusion of interwall intercalate. Further temperature increase up to 600-700 K is characterised with intercalate external surface desorption, stabilising the whole system and keeping the interwall intercalate only. The CNT's UV-spectrum (5,5)@(10,10) depending on the intercalate concentration and association constant of the "double-walled CNT-intercalate" system have been calculated. A combination of unique optical, electrical and magnetic behaviour of cyclopentadienyl complexes with their ability to form high-stable intercalate with CNT opens a prospect of their applying in nanotechnology. PMID:26951128

  1. A new way to synthesize superconducting metal-intercalated C60 and FeSe

    PubMed Central

    Takahei, Yuuki; Tomita, Keitaro; Itoh, Yugo; Ashida, Keishi; Lee, Ji-Hyun; Nishimoto, Naoki; Kimura, Takumi; Kudo, Kazutaka; Nohara, Minoru; Kubozono, Yoshihiro; Kambe, Takashi

    2016-01-01

    Doping with the optimum concentration of carriers (electrons or holes) can modify the physical properties of materials. Therefore, improved ways to achieve carrier doping have been pursued extensively for more than 50 years. Metal-intercalation is one of the most important techniques for electron doping of organic / inorganic solids, and has produced superconductors from insulators and metallic solids. The most successful examples are metal-intercalated graphite and C60 superconductors. Metal intercalation has been performed using solid-reaction and liquid solvent techniques. However, precise control of the quantity of intercalants in the target solids can be difficult to achieve using these methods, as that quantity depends largely on the initial conditions. Here we report an electrochemical method for metal-intercalation, and demonstrate the preparation of superconductors using organic and inorganic materials (C60 and FeSe). The metal atoms are effectively intercalated into the spaces in C60 and FeSe solids by supplying an electric current between electrodes in a solvent that includes electrolytes. The recorded superconducting transition temperatures, Tc’s, were the same as those of metal-intercalated C60 and FeSe prepared using solid-reaction or liquid solvent techniques. This technique may open a new avenue in the search for organic / inorganic superconductors. PMID:26732250

  2. Strong DNA deformation required for extremely slow DNA threading intercalation by a binuclear ruthenium complex.

    PubMed

    Almaqwashi, Ali A; Paramanathan, Thayaparan; Lincoln, Per; Rouzina, Ioulia; Westerlund, Fredrik; Williams, Mark C

    2014-10-01

    DNA intercalation by threading is expected to yield high affinity and slow dissociation, properties desirable for DNA-targeted therapeutics. To measure these properties, we utilize single molecule DNA stretching to quantify both the binding affinity and the force-dependent threading intercalation kinetics of the binuclear ruthenium complex Δ,Δ-[μ-bidppz-(phen)4Ru2]4+ (Δ,Δ-P). We measure the DNA elongation at a range of constant stretching forces using optical tweezers, allowing direct characterization of the intercalation kinetics as well as the amount intercalated at equilibrium. Higher forces exponentially facilitate the intercalative binding, leading to a profound decrease in the binding site size that results in one ligand intercalated at almost every DNA base stack. The zero force Δ,Δ-P intercalation Kd is 44 nM, 25-fold stronger than the analogous mono-nuclear ligand (Δ-P). The force-dependent kinetics analysis reveals a mechanism that requires DNA elongation of 0.33 nm for association, relaxation to an equilibrium elongation of 0.19 nm, and an additional elongation of 0.14 nm from the equilibrium state for dissociation. In cells, a molecule with binding properties similar to Δ,Δ-P may rapidly bind DNA destabilized by enzymes during replication or transcription, but upon enzyme dissociation it is predicted to remain intercalated for several hours, thereby interfering with essential biological processes. PMID:25245944

  3. A new way to synthesize superconducting metal-intercalated C60 and FeSe.

    PubMed

    Takahei, Yuuki; Tomita, Keitaro; Itoh, Yugo; Ashida, Keishi; Lee, Ji-Hyun; Nishimoto, Naoki; Kimura, Takumi; Kudo, Kazutaka; Nohara, Minoru; Kubozono, Yoshihiro; Kambe, Takashi

    2016-01-01

    Doping with the optimum concentration of carriers (electrons or holes) can modify the physical properties of materials. Therefore, improved ways to achieve carrier doping have been pursued extensively for more than 50 years. Metal-intercalation is one of the most important techniques for electron doping of organic / inorganic solids, and has produced superconductors from insulators and metallic solids. The most successful examples are metal-intercalated graphite and C60 superconductors. Metal intercalation has been performed using solid-reaction and liquid solvent techniques. However, precise control of the quantity of intercalants in the target solids can be difficult to achieve using these methods, as that quantity depends largely on the initial conditions. Here we report an electrochemical method for metal-intercalation, and demonstrate the preparation of superconductors using organic and inorganic materials (C60 and FeSe). The metal atoms are effectively intercalated into the spaces in C60 and FeSe solids by supplying an electric current between electrodes in a solvent that includes electrolytes. The recorded superconducting transition temperatures, Tc's, were the same as those of metal-intercalated C60 and FeSe prepared using solid-reaction or liquid solvent techniques. This technique may open a new avenue in the search for organic / inorganic superconductors. PMID:26732250

  4. A new way to synthesize superconducting metal-intercalated C60 and FeSe

    NASA Astrophysics Data System (ADS)

    Takahei, Yuuki; Tomita, Keitaro; Itoh, Yugo; Ashida, Keishi; Lee, Ji-Hyun; Nishimoto, Naoki; Kimura, Takumi; Kudo, Kazutaka; Nohara, Minoru; Kubozono, Yoshihiro; Kambe, Takashi

    2016-01-01

    Doping with the optimum concentration of carriers (electrons or holes) can modify the physical properties of materials. Therefore, improved ways to achieve carrier doping have been pursued extensively for more than 50 years. Metal-intercalation is one of the most important techniques for electron doping of organic / inorganic solids, and has produced superconductors from insulators and metallic solids. The most successful examples are metal-intercalated graphite and C60 superconductors. Metal intercalation has been performed using solid-reaction and liquid solvent techniques. However, precise control of the quantity of intercalants in the target solids can be difficult to achieve using these methods, as that quantity depends largely on the initial conditions. Here we report an electrochemical method for metal-intercalation, and demonstrate the preparation of superconductors using organic and inorganic materials (C60 and FeSe). The metal atoms are effectively intercalated into the spaces in C60 and FeSe solids by supplying an electric current between electrodes in a solvent that includes electrolytes. The recorded superconducting transition temperatures, Tc’s, were the same as those of metal-intercalated C60 and FeSe prepared using solid-reaction or liquid solvent techniques. This technique may open a new avenue in the search for organic / inorganic superconductors.

  5. Strong DNA deformation required for extremely slow DNA threading intercalation by a binuclear ruthenium complex

    PubMed Central

    Almaqwashi, Ali A.; Paramanathan, Thayaparan; Lincoln, Per; Rouzina, Ioulia; Westerlund, Fredrik; Williams, Mark C.

    2014-01-01

    DNA intercalation by threading is expected to yield high affinity and slow dissociation, properties desirable for DNA-targeted therapeutics. To measure these properties, we utilize single molecule DNA stretching to quantify both the binding affinity and the force-dependent threading intercalation kinetics of the binuclear ruthenium complex Δ,Δ-[μ‐bidppz‐(phen)4Ru2]4+ (Δ,Δ-P). We measure the DNA elongation at a range of constant stretching forces using optical tweezers, allowing direct characterization of the intercalation kinetics as well as the amount intercalated at equilibrium. Higher forces exponentially facilitate the intercalative binding, leading to a profound decrease in the binding site size that results in one ligand intercalated at almost every DNA base stack. The zero force Δ,Δ-P intercalation Kd is 44 nM, 25-fold stronger than the analogous mono-nuclear ligand (Δ-P). The force-dependent kinetics analysis reveals a mechanism that requires DNA elongation of 0.33 nm for association, relaxation to an equilibrium elongation of 0.19 nm, and an additional elongation of 0.14 nm from the equilibrium state for dissociation. In cells, a molecule with binding properties similar to Δ,Δ-P may rapidly bind DNA destabilized by enzymes during replication or transcription, but upon enzyme dissociation it is predicted to remain intercalated for several hours, thereby interfering with essential biological processes. PMID:25245944

  6. The effect of drug-DNA interactions on the intercalation site formation

    NASA Astrophysics Data System (ADS)

    Miroshnychenko, K. V.; Shestopalova, A. V.

    The problem of intercalation site formation in the undistorted B-DNA of different length and sequence was considered. Three models of DNA intercalation targets were proposed that accounted for the binding features of intercalators ethidium, daunomycin and 9-amino[N-(2-dimethylamino)ethyl]-acridine-4-carboxamide (9-amino-DACA). The automated docking of ligands into the constructed DNA-targets produced correct structures of complexes for ethidium and daunomycin when asymmetrically unwound DNA was used as target. To obtain the correct structure of 9-amino-DACA-DNA complex, the manual docking was applied. The results of docking of ligands into different DNA-targets indicate that, upon formation of the intercalation target, it is sufficient to take into account only the most significant unwinding in one particular helical step: in the intercalation step (for ethidium and 9-amino-DACA) or in the adjacent helical step (for daunomycin). The unwinding or overwinding of subsequent helical steps could be refined later during the optimization of the obtained intercalation complex. The unwinding of the DNA helical step on the large angle produces the 5‧-North/3‧-South asymmetry of sugar conformations in this step. The value of the total unwinding of the DNA in the intercalation complex was found to be dependent on the sequence and length of the DNA-target.

  7. The intercalation of bicyclic and tricyclic carboxylates into layered double hydroxides

    NASA Astrophysics Data System (ADS)

    Khan, Aamir I.; Williams, Gareth R.; Hu, Gang; Rees, Nicholas H.; O'Hare, Dermot

    2010-12-01

    Twenty-four nanocomposites built from layered double hydroxides and bicyclic and tricyclic carboxylates have been synthesised for the first time. Eight carboxylates were successfully intercalated into [LiAl 2(OH) 6]Cl· yH 2O, [Ca 2Al(OH) 6]NO 3· yH 2O, and [Mg 2Al(OH) 6]NO 3· yH 2O, and the products fully characterised. Guest species incorporated include 1-adamantane carboxylate (1- AC) and 5-norbornene-2- endo-3- exo-dicarboxylate. In some cases, carbonate anions were co-intercalated with the organic guest, and in others poorly crystalline aluminium hydroxides formed as by-products. Sharper resonances were observed in the 13C solid-state NMR spectra of the 1- AC intercalates than in the spectrum of pure 1- AC, suggesting increased order in the arrangement of the cyclic cages in the intercalates. Where possible, time-resolved in situ X-ray diffraction was employed to study the nanoscopic steps involved in the intercalation reactions. These investigations showed that the reactions are one-step processes, proceeding directly to the fully exchanged intercalate with no intermediate phases. The intercalation processes were found to be nucleation controlled.

  8. Antibiotic drug discovery.

    PubMed

    Wohlleben, Wolfgang; Mast, Yvonne; Stegmann, Evi; Ziemert, Nadine

    2016-09-01

    Due to the threat posed by the increase of highly resistant pathogenic bacteria, there is an urgent need for new antibiotics; all the more so since in the last 20 years, the approval for new antibacterial agents had decreased. The field of natural product discovery has undergone a tremendous development over the past few years. This has been the consequence of several new and revolutionizing drug discovery and development techniques, which is initiating a 'New Age of Antibiotic Discovery'. In this review, we concentrate on the most significant discovery approaches during the last and present years and comment on the challenges facing the community in the coming years. PMID:27470984

  9. Discovery and Classification in Astronomy

    NASA Astrophysics Data System (ADS)

    Dick, Steven J.

    2013-10-01

    Preface; Abbreviations; Introduction: the natural history of the heavens and the natural history of discovery; Part I. Entrée: 1. The Pluto affair; Part II. Narratives of Discovery: 2. Moons, rings, and asteroids: discovery in the realm of the planets; 3. In Herschel's gardens: nebulous discoveries in the realm of the stars; 4. Dwarfs, giants, and planets (again!): the discovery of the stars themselves; 5. Galaxies, quasars, and clusters: discovery in the realm of the galaxies; Part III. Patterns of Discovery: 6. The structure of discovery; 7. The varieties of discovery; 8. Discovery and classification; Part IV. Drivers of Discovery: 9. Technology and theory as drivers of discovery; Part V. The Synthesis of Discovery: 10. Luxuriant gardens and the master narrative; 11. The meaning of discovery; Appendix I; Appendix II.

  10. Cerium Oxide Nanoclusters on Graphene/Ru(0001): Intercalation of Oxygen via Spillover.

    PubMed

    Novotny, Zbynek; Netzer, Falko P; Dohnálek, Zdenek

    2015-08-25

    Cerium oxide is an important catalytic material known for its ability to store and release oxygen, and as such, it has been used in a range of applications, both as an active catalyst and as a catalyst support. Using scanning tunneling microscopy and Auger electron spectroscopy, we investigated oxygen interactions with CeOx nanoclusters on a complete graphene monolayer-covered Ru(0001) surface at elevated temperatures (600-725 K). Under oxidizing conditions (PO2 = 1 × 10(-7) Torr), oxygen intercalation under the graphene layer is observed. Time dependent studies demonstrate that the intercalation proceeds via spillover of oxygen from CeOx nanoclusters through the graphene (Gr) layer onto the Ru(0001) substrate and extends until the Gr layer is completely intercalated. Atomically resolved images further show that oxygen forms a p(2 × 1) structure underneath the Gr monolayer. Temperature dependent studies yield an apparent kinetic barrier for the intercalation of 1.21 eV. This value correlates well with the theoretically determined value for the reduction of small CeO2 clusters reported previously. At higher temperatures, the intercalation is followed by a slower etching of the intercalated graphene (apparent barrier of 1.60 eV). Vacuum annealing of the intercalated Gr leads to the formation of carbon monoxide, causing etching of the graphene film, demonstrating that the spillover of oxygen is not reversible. In agreement with previous studies, no intercalation is observed on a complete graphene monolayer without CeOx clusters, even in the presence of a large number of point defects. These studies demonstrate that the easily reducible CeOx clusters act as intercalation gateways capable of efficiently delivering oxygen underneath the graphene layer. PMID:26230753

  11. Synthesis of reduced graphene oxide intercalated ZnO quantum dots nanoballs for selective biosensing detection

    NASA Astrophysics Data System (ADS)

    Chen, Jing; Zhao, Minggang; Li, Yingchun; Fan, Sisi; Ding, Longjiang; Liang, Jingjing; Chen, Shougang

    2016-07-01

    ZnO quantum dots (QDs), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) are always used in sensors due to their excellent electrochemical characteristics. In this work, ZnO QDs were intercalated by rGO sheets with cross-linked MWCNTs to construct intercalation nanoballs. A MWCNTs/rGO/ZnO QDs 3D hierarchical architecture was fabricated on supporting Ni foam, which exhibited excellent mechanical, kinetic and electrochemical properties. The intercalation construction can introduce strong interfacial effects to improve the surface electronic state. The selectively determinate of uric acid, dopamine, and ascorbic acid by an electrode material using distinct applied potentials was realized.

  12. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    NASA Technical Reports Server (NTRS)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  13. Unique properties of α-NaFeO{sub 2}: De-intercalation of sodium via hydrolysis and the intercalation of guest molecules into the extract solution

    SciTech Connect

    Monyoncho, Evans; Bissessur, Rabin

    2013-07-15

    Graphical abstract: - Highlights: • Facile de-intercalating Na from NaFeO2. • Formation of layered sodium hydrogen carbonate hydrate. • Intercalation chemistry on layered sodium hydrogen carbonate hydrate. - Abstract: We report on a versatile method for the de-intercalation of Na from α-NaFeO{sub 2} by using water to produce α-Na{sub 1−x}FeO{sub 2}, where x ≈ 1. This de-intercalation technique provides an excellent route to ion exchange Na with other metal ions in α-NaFeO{sub 2}. The hydrolysis mechanism is provided. We show that the extracted solution captures CO{sub 2} from the atmosphere leading to the formation of sodium hydrogen carbonate hydrate crystals. The lamellar structure of the hydrate crystals was confirmed by powder X-ray diffraction, and were found Na-deficient via elemental analysis. Intercalation of guest molecules such as polymers, alcohols, and inorganic ions into the gallery space of the newly formed sodium hydrogen carbonate hydrate crystals was demonstrated by the use of powder X-ray diffraction technique. The reported materials were also characterized by Mössbauer spectroscopy, thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy.

  14. Drug discovery in academia.

    PubMed

    Verkman, A S

    2004-03-01

    Drug discovery and development is generally done in the commercial rather than the academic realm. Drug discovery involves target discovery and validation, lead identification by high-throughput screening, and lead optimization by medicinal chemistry. Follow-up preclinical evaluation includes analysis in animal models of compound efficacy and pharmacology (ADME: administration, distribution, metabolism, elimination) and studies of toxicology, specificity, and drug interactions. Notwithstanding the high-cost, labor-intensive, and non-hypothesis-driven aspects of drug discovery, the academic setting has a unique and expanding niche in this important area of investigation. For example, academic drug discovery can focus on targets of limited commercial value, such as third-world and rare diseases, and on the development of research reagents such as high-affinity inhibitors for pharmacological "gene knockout" in animal models ("chemical genetics"). This review describes the practical aspects of the preclinical drug discovery process for academic investigators. The discovery of small molecule inhibitors and activators of the cystic fibrosis transmembrane conductance regulator is presented as an example of an academic drug discovery program that has yielded new compounds for physiology research and clinical development. PMID:14761879

  15. Decades of Discovery

    DOE R&D Accomplishments Database

    2011-06-01

    For the past two-and-a-half decades, the Office of Science at the U.S. Department of Energy has been at the forefront of scientific discovery. Over 100 important discoveries supported by the Office of Science are represented in this document.

  16. Serendipity and Scientific Discovery.

    ERIC Educational Resources Information Center

    Rosenman, Martin F.

    1988-01-01

    The discovery of penicillin is cited in a discussion of the role of serendipity as it relates to scientific discovery. The importance of sagacity as a personality trait is noted. Successful researchers have questioning minds, are willing to view data from several perspectives, and recognize and appreciate the unexpected. (JW)

  17. Friends' Discovery Camp

    ERIC Educational Resources Information Center

    Seymour, Seth

    2008-01-01

    This article features Friends' Discovery Camp, a program that allows children with and without autism spectrum disorder to learn and play together. In Friends' Discovery Camp, campers take part in sensory-rich experiences, ranging from hands-on activities and performing arts to science experiments and stories teaching social skills. Now in its 7th…

  18. "Eureka, Eureka!" Discoveries in Science

    ERIC Educational Resources Information Center

    Agarwal, Pankaj

    2011-01-01

    Accidental discoveries have been of significant value in the progress of science. Although accidental discoveries are more common in pharmacology and chemistry, other branches of science have also benefited from such discoveries. While most discoveries are the result of persistent research, famous accidental discoveries provide a fascinating…

  19. Drug-nucleic acid interactions: conformational flexibility at the intercalation site.

    PubMed Central

    Berman, H M; Neidle, S; Stodola, R K

    1978-01-01

    The conformational features of the intercalation site in polynucleotides were examined. We found that, for all the crystal structures of drug-dinucleoside complexes studied thus far, two torsion angles differ from those found in A RNA (phi and chi) and that alternate sugar puckering is not a prerequisite for intercalation. This intercalation geometry, which is the basis of helix axis displacement in a polymer, would necessitate conformational changes in the adjacent nucleotides. The base-turn angle is less sensitive to the conformation of the backbone than it is to small alterations in the base-pairing geometry. We postulate that this angle is dependent on the nature of the intercalating drug. PMID:273246

  20. Optimization of the Thermoelectric Figure of Merit in Crystalline C60 with Intercalation Chemistry.

    PubMed

    Kim, Jeong Yun; Grossman, Jeffrey C

    2016-07-13

    Crystalline C60 is an appealing candidate material for thermoelectric (TE) applications due to its extremely low thermal conductivity and potentially high electrical conductivity with metal atom intercalation. We investigate the TE properties of crystalline C60 intercalated with alkali and alkaline earth metals using both classical and quantum mechanical calculations. For the electronic structure, our results show that variation of intercalated metal atoms has a large impact on energy dispersions, which leads to broad tunability of the power factor. For the thermal transport, we show that dopants introduce strong phonon scattering into crystalline C60, leading to considerably lower thermal conductivity. Taking both into account, our calculations suggest that appropriate choice of metal atom intercalation in crystalline C60 could yield figures of merit near 1 at room temperature. PMID:27322341

  1. A micrographic and gravimetric study of intercalation and deintercalation of graphite fibers

    NASA Technical Reports Server (NTRS)

    Hung, C. C.

    1985-01-01

    Intercalation and deintercalation of Union Carbide P-100 graphite fibers with liquid and vaporous bromine was studied gravimetrically and microscopically. The mass of the bromine intercalated fibers was found to be 17 to 20 percent greater than their pristine counterpart. This variation decreased to 17 to 18 percent after heating in air for 3 days at 200 C and to 14.5 to 18 percent after 6 days of 260 C heating. The fiber length did not change throughout the experiment. The fiber diameter increased during intercalation and decreased slightly upon deintercalation but was not affected by heating to 260 C for 3 days in air. Comparing the mass and volume data to those with highly oriented pyrolitic graphite or natural single crystal graphite suggested the possibility that the intercalated P-100 fibers could be mostly stage 4.

  2. Novel alkylimidazolium/vanadium pentoxide intercalation compounds with excellent adsorption performance for methylene blue

    NASA Astrophysics Data System (ADS)

    Kong, AiGuo; Ding, Yong Jie; Wang, Ping; Zhang, Heng Qiang; Yang, Fan; Shan, Yong Kui

    2011-02-01

    Novel alkylimidazolium-intercalated V 2O 5 compounds were synthesized by a redox reaction between iodide ion and V 2O 5. The X-ray photoelectron spectroscopy and the diffuse reflectance UV-vis spectrometry experiments reveal that the vanadium in the intercalated V 2O 5 products was partially reduced by an iodide ion and the resultant iodine can be removed in the final products. The transmission electron microscope observation and X-ray diffraction analysis testify that the prepared alkylimidazolium/V 2O 5 intercalation compounds have typical lamellar structure with different d100 interlayer spacing values and the special straw-like nanofiber morphology with the length of 0.5-10 μm. Systematic investigation indicates that new intercalation compounds possess the extraordinary adsorption performance for methylene blue in an aqueous solution.

  3. Fabrication of a single layer graphene by copper intercalation on a SiC(0001) surface

    SciTech Connect

    Yagyu, Kazuma; Tochihara, Hiroshi; Tomokage, Hajime; Suzuki, Takayuki; Tajiri, Takayuki; Kohno, Atsushi; Takahashi, Kazutoshi

    2014-02-03

    Cu atoms deposited on a zero layer graphene grown on a SiC(0001) substrate, intercalate between the zero layer graphene and the SiC substrate after the thermal annealing above 600 °C, forming a Cu-intercalated single layer graphene. On the Cu-intercalated single layer graphene, a graphene lattice with superstructure due to moiré pattern is observed by scanning tunneling microscopy, and specific linear dispersion at the K{sup ¯} point as well as a characteristic peak in a C{sub 1s} core level spectrum, which is originated from a free-standing graphene, is confirmed by photoemission spectroscopy. The Cu-intercalated single layer graphene is found to be n-doped.

  4. Reversible chemochromic MoO3 nanoribbons through zerovalent metal intercalation.

    PubMed

    Wang, Mengjing; Koski, Kristie J

    2015-03-24

    Molybdenum trioxide (α-MoO3) is a 2D layered oxide with use in electrochromic and photochromic devices owing to its ability to reversibly change color between transparent and light blue with electrochemical or hydrogen intercalation. Despite its significant application potential, MoO3 performance is largely limited by the destructiveness of these intercalation techniques, insignificant coloration, and slow color response. We demonstrate a reversible chemochromic method, using intercalation of zerovalent metals into α-MoO3 nanoribbons (Sn, ∼2 at. %; Co, ∼4 at. %), to chemically alter MoO3 from transparent white to a deep blue indigo, resulting in enhanced coloration and chemically tunable optical properties. We present two strategies to reversibly tune the color response of MoO3 nanoribbons. Chromism can be reversed (i) by complete oxidative deintercalation with hydrogen peroxide or iodine or (ii) through a temperature-driven disorder-order phase transition of the intercalated zerovalent metal. PMID:25734624

  5. Strain-enhanced superconductivity of Mo X2(X =S or Se) bilayers with Na intercalation

    NASA Astrophysics Data System (ADS)

    Zhang, Jun-Jie; Gao, Bin; Dong, Shuai

    2016-04-01

    Mo X2(X =S or Se) is a semiconductor family with two-dimensional structure. And a recent calculation predicted the superconductivity in the electron-doped MoS2 monolayer. In this work, the electronic structure and lattice dynamics of Mo X2 bilayers with monolayer Na intercalated have been calculated. According to the electron-phonon interaction, it is predicted that these bilayers can be transformed from indirect-gap semiconductors to superconductors by Na intercalation. More interestingly, the biaxial tensile strain can significantly enhance the superconducting temperature up to ˜10 K in Na-intercalated MoS2. In addition, the phonon mean free path at room temperature is also greatly improved in Na-intercalated MoSe2, which is advantageous for related applications.

  6. Gd(III) complexes intercalated into hydroxy double salts as potential MRI contrast agents.

    PubMed

    Jin, Miao; Spillane, Dominic E M; Geraldes, Carlos F G C; Williams, Gareth R; Bligh, S W Annie

    2015-12-21

    The ion exchange intercalation of two Gd-based magnetic resonance imaging contrast agents into hydroxy double salts (HDSs) is reported. The presence of Gd(3+) diethylenetriaminepentaacetate and Gd(3+) diethylenetriaminepenta(methylenephosphonate) complexes in the HDS lattice after intercalation was confirmed by microwave plasma-atomic emission spectroscopy. The structural aspects of the HDS-Gd composites were studied by X-ray diffraction, with the intercalates having an interlayer spacing of 14.5-18.6 Å. Infrared spectroscopy confirmed the presence of characteristic vibration peaks associated with the Gd(3+) complexes in the intercalation compounds. The proton relaxivities of the Gd(3+) complex-loaded composites were 2 to 5-fold higher in longitudinal relaxivity, and up to 10-fold higher in transverse relaxivity, compared to solutions of the pure complexes. These data demonstrate that the new composites reported here are potentially potent MRI contrast agents. PMID:26568157

  7. Synthesis of new oligothiophene derivatives and their intercalation compounds: Orientation effects

    USGS Publications Warehouse

    Ibrahim, M.A.; Lee, B.-G.; Park, N.-G.; Pugh, J.R.; Eberl, D.D.; Frank, A.J.

    1999-01-01

    The orientation dependence of intercalated oligothiophene derivatives in vermiculite and metal disulfides MS2 (M = Mo, Ti and Zr) on the pendant group on the thiophene ring and the host material was studied by X-ray diffraction (XRD) and solid state nuclear magnetic resonance spectroscopy. Amino and nitro derivatives of bi-, ter- and quarter-thiophenes were synthesized for the first time. The amino-oligothiophenes were intercalated into vermiculite by an exchange reaction with previously intercalated octadecylammonium vermiculite and into MS2 by the intercalation-exfoliation technique. Analysis of the XRD data indicates that a monolayer of amino-oligothiophene orients perpendicularly to the silicate surface in vermiculite and lies flat in the van der Waals gap of MS2.

  8. Periodic arrays of intercalated atoms in twisted bilayer graphene: An ab initio investigation

    NASA Astrophysics Data System (ADS)

    Miwa, R. H.; Venezuela, P.; Morell, Eric Suárez

    2015-09-01

    We have performed an ab initio investigation of transition metals (TMs =Mo ,Ru ,Co ,andPt ) embedded in twisted bilayer graphene (tBG) layers. Our total energy results reveal that, triggered by the misalignment between the graphene layers, Mo and Ru atoms may form a quasiperiodic (triangular) array of intercalated atoms. In contrast, the formation of those structures is not expected for the other TMs, the Co and Pt atoms. The net magnetic moment (m ) of Mo and Ru atoms may be quenched upon intercalation, depending on the stacking region (AA or AB). For instance, we find a magnetic moment of 0.3 μB(1.8 μB) for Ru atoms intercalated between the AA (AB) regions of the stacked twisted layers. Through simulated scanning tunneling microscopy (STM) images, we verify that the presence of intercalated TMs can be identified by the formation of bright (hexagonal) spots lying on the graphene surface.

  9. Preparation of titanate nanosheets and nanoribbons by exfoliation of amine intercalated titanates.

    PubMed

    Jeffery, A Anto; Pradeep, A; Rajamathi, Michael

    2016-05-14

    Amine intercalated titanates were synthesized by direct exchange of potassium ions of K2Ti4O9 by alkyl ammonium ions of various alkyl chain lengths. These intercalated solids exfoliate well in alcohols of different alkyl chain lengths and non-polar solvents such as toluene and hexane to yield colloidal dispersions of titanate nanosheets. The longer the alkyl chain of the intercalated amine the better the exfoliation of the intercalated titanate in long chain alcohols and non-polar solvents. While non-uniform rectangular nanosheets were obtained when aggressive sonication was employed for exfoliating the solids, nanoribbons were obtained when the exfoliation was carried out by gently stirring the solids in the solvent. PMID:27089839

  10. Selective intercalation of o-phenylene diamine into molybdenum oxide layers

    SciTech Connect

    Shao Ke Cao Huiqun; Qiu Qi

    2009-03-05

    o-Phenylene diamine molecules were intercalated into molybdenum oxide layers by an in situ co-precipitation method. The structure and composition of the intercalated material were studied by X-ray diffraction (XRD), infrared spectroscopy (IR) and elemental analysis. XRD data evidenced a layered structure with a spacing of 18 A, which corresponds to an organic-inorganic hybrid-layered structure. IR and UV-vis spectra indicated the polymerization of o-phenylene between the molybdenum oxide layers. It was also observed that compared with aniline molecules, o-phenylene diamine molecules can be selectively intercalated into molybdenum oxide layers. We provide evidence that affinity for o-phenylene diamine to form intermolecular polymers is the reason for its selective intercalation. The polymer chain structure of o-phenylene diamine makes it a preferential guest species compared with aniline. We believe that this opens a new way to create organic-inorganic hybrid structures.