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Sample records for lithium fluoride crystals

  1. Luminescence from Edge Fracture in Shocked Lithium Fluoride Crystals

    SciTech Connect

    Turley, W. D.; Stevens, G. D.; Capelle, G. A.; Grover, M.; Holtkamp, D. B.; LaLone, B. M.; Veeser, L. R.

    2013-01-01

    Light emitted from a [100] lithium fluoride crystal was characterized under shock wave compression to 28GPa followed by complete stress release at the edges. The light was examined using time-gated optical spectrometry and imaging, time-resolved optical emission measurements, and hydrodynamic modeling. The shock arrival at the circumference of the crystal was delayed relative to the center so that the two regions could be studied at different times. The majority of the light emission originated when the shock waves released at the circumference of the crystal. Unlike previously reported results for shocked lithium fluoride, we found that the light spectrum is not strictly broad band, but has spectral lines associated with atomic lithium in addition to a broad band background. Also, the emission spectrum depends strongly on the gas surrounding the sample. Based on our observations, the line emission appears to be related to fracture of the lithium fluoride crystal from the shock wave releasing at the edges. Experimenters frequently utilize lithium fluoride crystals as transparent windows for observing shock compressed samples. Because of the experimental geometries used, the shock wave in such cases often reaches the circumference of the window at nearly the same moment as when it reaches the center of the sample-window interface. Light generated at the circumference could contaminate the measurement at the interface when this light scatters into the observed region. This background light may be reduced or avoided using experimental geometries which delay the arrival of the shock wave at the edges of the crystal.

  2. Reduction of precursor decay anomaly in single crystal lithium fluoride

    NASA Astrophysics Data System (ADS)

    Sano, Yukio

    2000-08-01

    The purpose of this study is to reveal that the precursor decay anomaly in single crystal lithium fluoride is reduced by Sano's decay curve [Y. Sano, J. Appl. Phys. 85, 7616 (1999)], which is much smaller in slope than Asay's decay curve [J. R. Asay, G. R. Fowles, G. E. Duvall, M. H. Miles, and R. F. Tinder, J. Appl. Phys. 43, 2132 (1972)]. To this end, strain, particle, velocity, and stress in a precursor and near the leading edge of the follower changing with time along Sano's decay curve are first analyzed quantitatively. The analysis verified the existence of degenerate contraction waves I and II and a subrarefaction wave R', and the decay process [Y. Sano, J. Appl. Phys. 77, 3746 (1995)] caused in sequence by evolving followers C, I, II, R', Rb. Next, inequalities relating decay rates qualitatively to plastic strain rates at the leading edge of the follower, which are derived using the properties of the followers, are incorporated into the analysis. Calculation results showed that the plastic strain rates were reduced by low decay rates. This indicates that the precursor decay anomaly might be greatly reduced by Sano's decay curve.

  3. Void control in the crystallization of lithium fluoride

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Perry, William D.

    1991-01-01

    The effect of tungsten-coated graphite fibers on the radiant heat transfer characteristics of salt-fiber composites was studied by measuring the onset of melting as a function of applied furnace power. As the fiber concentration was increased from 0 to 5.40 percent fiber by weight, the furnace temperature required to melt the lithium fluoride also increased. Upon cooling, each of the crystalline salt-fiber composites were cut open with a diamond saw to expose the void. Optical photographs of the voids revealed a trend in void location and size, with the largest void, and the least change in the outer dimension of the boule upon cooling, occurring in the sample with the most fiber.

  4. Fluorescent detection of single tracks of alpha particles using lithium fluoride crystals

    NASA Astrophysics Data System (ADS)

    Bilski, P.; Marczewska, B.

    2017-02-01

    Lithium fluoride single crystals were successfully used for fluorescent imaging of single tracks of alpha particles. This was realized with a standard wide-field fluorescent microscope equipped with a 100× objective. Alpha particles create F2 and F3+ color centers in LiF crystals. The subsequent illumination with the blue light (wavelength around 445 nm), excites these centers and produces fluorescence with a broad band peaked at 670 nm. The observed tracks of alpha particles have diameter of about 500 nm. Focusing of the microscope at different depths in a LiF crystal, enables imaging changes of shape and position of tracks, allowing for visualization of their paths. These encouraging results are the first step towards practical application of LiF as fluorescent nuclear track detectors.

  5. Factors Affecting the Plasticity of Sodium Chloride, Lithium Fluoride, and Magnesium Oxide Single Crystals. 1

    NASA Technical Reports Server (NTRS)

    Stearns, Carl A.; Pack, Ann E.; Lad, Robert A.

    1959-01-01

    A study was made of the relative magnitude of the effects of various factors on the ductility of single crystals of sodium chloride (NaCl), lithium fluoride (LiF), and magnesium oxide (MgO). Specimen treatments included water-polishing, varying cleavage rate, annealing, quenching, X-irradiation, surface coating, aging, and combinations of some of these treatments. The mechanical behavior of the crystals was studied in flexure and in compression, the latter study being performed at both constant strain rate and constant load. Etch-pit studies were carried out to provide some pertinent information on the results of pretreatment on the dislocation concentration and distribution in the vicinity of the surface. The load deformation curves for these ionic single crystals show an initial region of very low slope which proved to be due to anelastic deformation. The extent of initial anelastic deformation is modified by specimen pretreatment in a way that suggests that this deformation is the result of expansion of cleaved-in dislocation loops, which can contract on the removal of the stress. The effects of the various pretreatments on the load and deflection at fracture are in accord with the prediction one might make with regard to their effect on the nucleation of fatal surface cracks. For NaCl, increases in ductility are always accompanied by increases in strength. The creep constants for NaCl are a function of treatments which affect the bulk structure but are not a function of treatments which only affect the surface.

  6. Optical characterization of femtosecond laser induced active channel waveguides in lithium fluoride crystals

    NASA Astrophysics Data System (ADS)

    Chiamenti, I.; Bonfigli, F.; Gomes, A. S. L.; Michelotti, F.; Montereali, R. M.; Kalinowski, H. J.

    2014-01-01

    We successfully realized broad-band light-emitting color center waveguides buried in LiF crystals by using femtosecond laser pulses. The characterization of the waveguides was performed by optical microscopy, photoluminescence spectra, loss measurements and near-field profiling. The experimental results show that the direct-writing fabrication process induces low-index contrast active channel waveguides: their wavelength-dependent refractive index changes, estimated from 10-3 to 10-4 depending on the writing conditions, allow supporting few modes at visible and near-infrared wavelengths.

  7. Optical characterization of femtosecond laser induced active channel waveguides in lithium fluoride crystals

    SciTech Connect

    Chiamenti, I.; Kalinowski, H. J.; Bonfigli, F.; Montereali, R. M.; Gomes, A. S. L.; Michelotti, F.

    2014-01-14

    We successfully realized broad-band light-emitting color center waveguides buried in LiF crystals by using femtosecond laser pulses. The characterization of the waveguides was performed by optical microscopy, photoluminescence spectra, loss measurements and near-field profiling. The experimental results show that the direct-writing fabrication process induces low-index contrast active channel waveguides: their wavelength-dependent refractive index changes, estimated from 10{sup −3} to 10{sup −4} depending on the writing conditions, allow supporting few modes at visible and near-infrared wavelengths.

  8. Optical spectroscopy and imaging of colour centres in lithium fluoride crystals and thin films irradiated by 3 MeV proton beams

    NASA Astrophysics Data System (ADS)

    Piccinini, M.; Ambrosini, F.; Ampollini, A.; Carpanese, M.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Vincenti, M. A.; Montereali, R. M.

    2014-05-01

    Lithium fluoride is a well-known dosimeter material and it is currently under investigation also for high-resolution radiation imaging detectors based on colour centre photoluminescence. In order to extend their applications, proton beams of 3 MeV energy, produced by a linear accelerator, were used to irradiate LiF crystals and thin films in the fluence range of 1010-1015 protons/cm2. The irradiation induces the formation of colour centres, mainly the primary F centre and the aggregate F2 and F3+ defects, which are stable at room temperature. By optical pumping in the blue spectral region, the F2 and F3+ centres emit broad photoluminescence bands in the visible spectral range. By conventional fluorescence microscopy, the integrated photoluminescence intensity was carefully measured in LiF crystals and thin films as a function of the irradiation fluence: a linear optical response was obtained in a large range of fluence, which is dependent on the used LiF samples. Colour centres concentrations were estimated in LiF crystals by optical absorption spectroscopy. It was possible to record the transversal proton beam intensity profile by acquiring the photoluminescence image of the irradiated spots on LiF films.

  9. Fabrication of nanoscale patterns in lithium fluoride crystal using a 13.5 nm Schwarzschild objective and a laser produced plasma source.

    PubMed

    Wang, Xin; Mu, Baozhong; Jiang, Li; Zhu, Jingtao; Yi, Shengzhen; Wang, Zhanshan; He, Pengfei

    2011-12-01

    Lithium fluoride (LiF) crystal is a radiation sensitive material widely used as EUV and soft x-ray detector. The LiF-based detector has high resolution, in principle limited by the point defect size, large field of view, and wide dynamic range. Using LiF crystal as an imaging detector, a resolution of 900 nm was achieved by a projection imaging of test meshes with a Schwarzschild objective operating at 13.5 nm. In addition, by imaging of a pinhole illuminated by the plasma, an EUV spot of 1.5 μm diameter in the image plane of the objective was generated, which accomplished direct writing of color centers with resolution of 800 nm. In order to avoid sample damage and contamination due to the influence of huge debris flux produced by the plasma source, a spherical normal-incidence condenser was used to collect EUV radiation. Together with a description of experimental results, the development of the Schwarzschild objective, the influence of condenser on energy density and the alignment of the imaging system are also reported.

  10. Fluoride glass: Crystallization, surface tension

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.

    1988-01-01

    Fluoride glass was levitated acoustically in the ACES apparatus on STS-11, and the recovered sample had a different microstructure from samples cooled in a container. Further experiments on levitated samples of fluoride glass are proposed. These include nucleation, crystallization, melting observations, measurement of surface tension of molten glass, and observation of bubbles in the glass. Ground experiments are required on sample preparation, outgassing, and surface reactions. The results should help in the development and evaluation of containerless processing, especially of glass, in the development of a contaminent-free method of measuring surface tensions of melts, in extending knowledge of gas and bubble behavior in fluoride glasses, and in increasing insight into the processing and properties of fluoride glasses.

  11. Fluoride laser crystals: old and new

    NASA Astrophysics Data System (ADS)

    Jenssen, Hans P.; Cassanho, Arlete

    2006-02-01

    The development of oxide and fluoride materials as gain materials of choice for solid state lasers ranges from early materials such as Calcium Fluoride and Calcium Tungstate crystals to the now ubiquitous Nd hosts YLF, YAG and Vanadate. Among Tunable laser materials, MgF II - an early favorite, gave way to superior oxides such as Alexandrite and Ti:Sapphire only to be followed by development of still newer tunable fluoride media, notably, fluoride colquiriites such as Cr-doped LiSAF and LiCaF. Newer fluoride crystals, such as Barium Yttrium Fluoride BaY II F 8 (BYF), KY 3F 10 (KYF) and the tunable Cr doped LiCaGaF 6 are attractive laser materials, but their growth has not been optimized. Key advantages of two of these new crystals are discussed. Crystal growth results for BYF and Cr:LiCaGaF 6 as well as some material characterization are presented.

  12. Surface crystallization of a fluoride glass

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Doremus, Robert H.

    1983-01-01

    Growth of crystals on the surface of a Zr-Ba-La fluoride glass was observed by optical and scanning electron microscopy. Small, dark crystal nucleated rapidly and grew to a size of about 10 microns; then they stopped growing, and wrinkled regions emerged, covering the entire crystal surface.

  13. Neutron Fading Characteristics of Copper Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)

    DTIC Science & Technology

    2008-05-21

    Fading Characteristics of Copper-Doped Lithium Fluoride (LiF: MCP) Thermoluminescent Dosimeters (TLDs)" Name of Candidate: L T Jeffrey A. Delzer Master...Lithium Fluoride Thermoluminescent Dosimeters beyond brief excerpts is with the permission of the copyright owner, and will save and hold harmless...Thesis: Author: Thesis directed by: ABSTRACT "Neutron Fading Characteristics of Copper-Doped Lithium Fluoride (LiF: MCP) Thermoluminescent

  14. Crystallization of lithium borate glasses

    NASA Technical Reports Server (NTRS)

    Goktas, A. A.; Neilson, G. F.; Weinberg, M. C.

    1992-01-01

    The glass-forming ability and crystallization behavior of lithium borate compositions, in the diborate-to-metaborate-range, were studied. In particular, the nature and sequence of formation of crystalline phases and the tendency toward devitrification were investigated as functions of temperature, thermal history and batch composition. It was found that the sequence of crystalline phase formation was sensitive to all of the three latter factors, and it was observed that under certain conditions metastable defect structures of the metaborate can appear.

  15. Formation of lithium fluoride/metal nanocomposites for energy storage through solid state reduction of metal fluorides

    SciTech Connect

    Amatucci, GG; Pereira, N; Badway, F; Sina, M; Cosandey, F; Ruotolo, M; Cao, C

    2011-12-01

    In order to utilize high energy metal fluoride electrode materials as direct replacement electrode materials for lithium ion batteries in the future, a methodology to prelithiate the cathode or anode must be developed. Herein, we introduce the use of a solid state Li(3)N route to achieve the lithiation and mechanoreduction of metal fluoride based nanocomposites. The resulting prelithiation was found to be effective with the formation of xLiF:Me structures of very fine nanodimensions analogous to what is found by electrochemical lithiation. Physical and electrochemical properties of these nanocomposites for the bismuth and iron lithium fluoride systems are reported. (C) 2011 Elsevier B.V. All rights reserved.

  16. Spatial diagnostics of the laser induced lithium fluoride plasma

    SciTech Connect

    Baig, M. A.; Qamar, Aisha; Fareed, M. A.; Anwar-ul-Haq, M.; Ali, Raheel

    2012-06-15

    We present spatial characteristics of the lithium fluoride plasma generated by the fundamental and second harmonic of a Nd:YAG laser. The plume emission has been recorded spatially using five spectrometers covering the spectral region from 200 nm to 720 nm. The electron density is measured from the Stark broadened line profile of the line at 610.37 nm, whereas the plasma temperature has been determined using the Boltzmann plot method including all the observed spectral lines of lithium. Both the plasma parameters; electron density and plasma temperature decrease with the increase of the distance from the target surface. The thermal conduction towards the target, the radiative cooling of the plasma, and the conversion of thermal energy into kinetic energy are the main mechanisms responsible for the spatially decrease of the plasma parameters.

  17. Optical Restoration of Lead Fluoride Crystals

    SciTech Connect

    Spilker, A.; Cole, P. L.; Forest, T. A.; Mestari, M.; Naeem, S.; LeBaron, N.; Bertin, P.; Camacho, C. Munoz; Roche, J.

    2009-03-10

    Due to its relatively high resistance to high radiation, lead fluoride (PbF{sub 2}) crystals are becoming an increasingly popular material of choice for electromagnetic calorimetry, such as for experiments requiring the measurement of high-energy photons in Hall A of Jefferson Lab. For our studies we irradiated the PbF{sub 2} crystals using an electron linear accelerator (LINAC) followed by exposing the crystals to blue light so as to restore the nominal optical properties. This technique of optical bleaching with blue light affords an efficient and low-cost means for reversing the deleterious effects of optical transmission loss in radiation-damaged lead fluoride crystals. Whereas earlier experiments irradiated the PbF{sub 2} samples with 1.1 and 1.3 MeV gammas from {sup 60}Co, we used pulsed beams of energetic electrons from the tunable 25-MeV LINAC at Idaho Accelerator Center of Idaho State University in Pocatello, Idaho. A 20-MeV beam of electrons was targeted onto four separate 19 cm length samples of lead fluoride over periods of 1, 2, and 4 hours yielding doses between 7 kGy and 35 kGy. Samples were then bleached with blue light of wavelength 410-450 nm for periods between 19.5 and 24 hours. We performed this process twice - radiation, bleaching, radiation, and then followed by bleaching again - for each of these four PbF{sub 2} samples. We shall discuss the efficacy of blue light curing on samples that have undergone two cycles of electron irradiation and optical bleaching.

  18. Effects of Systemic Fluoride and in vitro Fluoride Treatment on Enamel Crystals

    PubMed Central

    Chen, H.; Czajka-Jakubowska, A.; Spencer, N.J.; Mansfield, J.F.; Robinson, C.; Clarkson, B.H.

    2008-01-01

    Systemically administered fluoride at a concentration of 75 ppm increases the surface roughness of developing enamel crystals in rats, which may be significant in advancing our understanding of the biological mechanism of fluorosis. Thus, the aim of this study was to investigate whether the increased surface roughness may be a result of surface restructuring by the direct action of fluoride at the crystal surface. We examined the fluoride dose-dependent roughening of enamel crystal surfaces in vivo, in the rat, and whether this roughening could be mimicked by the in vitro treatment of rat enamel crystals with neutral pH fluoride solutions. Our results showed that enamel crystal surface roughness increased after treatment with increasing fluoride ion concentrations, whether applied in vitro or administered systemically. This suggests a mechanism, alongside others, for the increased surface roughness of crystals in fluorotic enamel. PMID:17062747

  19. Crystallization of heavy metal fluoride glasses

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Bruce, Allan J.; Doremus, R. H.; Moynihan, C. T.

    1984-01-01

    The kinetics of crystallization of a number of fluorozirconate glasses were studied using isothermal and dynamic differential scanning calorimetry and X-ray diffraction. The addition of the fluorides LiF, NaF, AlF3, LaF3 to a base glass composition of ZrF4-BaF2 reduced the tendency to crystallize, probably by modifying the viscosity-temperature relation. ZrF4-BaF2-LaF3-AlF3-NaF glass was the most stable against devitrification and perhaps is the best composition for optical fibers with low scattering loss. Some glasses first crystallize out into metastable beta-BaZr2F10 and beta-BaZrF6 phases, which transform into the most stable alpha-phases when heated to higher temperatures. The size of the crystallites was estimated to be about 600 A from X-ray diffraction.

  20. Zirconium fluoride glass - Surface crystals formed by reaction with water

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

    1984-01-01

    The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

  1. Synthesis and Crystallization Behavior of Fluoride Glasses

    DTIC Science & Technology

    1989-08-22

    metal fluoride glasses. Exploration of synthesis conditions for converting precursors to multicomponent oxide gels for conversion to heavy metal fluoride...glasses. Exploration of chemistries and conditions for converting multicomponent oxide gels to heavy metal fluoride glasses. Exploration of...chemical approaches to passivating the surfaces of heavy metal fluoride glasses. Exploration of the possibility of developing a computer model to describe

  2. Materials corrosion in molten lithium fluoride-sodium fluoride-potassium fluoride eutectic salt

    NASA Astrophysics Data System (ADS)

    Olson, Luke Christopher

    Static corrosion studies were undertaken to determine the compatibility of several candidate high temperature materials for a heat transfer loop in a molten alkali fluoride eutectic salt, LiF-NaF-KF: 46.5-11.5-42 mol % (commonly referred to as FLiNaK), as well as a molten chloride near eutectic salt, KCl-MgCl2: 68-32 mol %. Several high temperature alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, Nb-1Zr, a nearly pure Ni alloy Ni-201, and a C/SiSiC ceramic were exposed to molten FLiNaK at 850°C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion occurred predominantly from dealloying of Cr from the Cr bearing alloys, an effect that was particularly pronounced at the grain boundaries. Corrosion was noted to occur from selective attack of the Si phase in the C/SiSiC ceramic. Alloy weight-loss/area due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys' weight-loss/area was also found to correlate to the concentration of carbon present in the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. The corrosion mechanisms for the chloride based salt were found to be similar to those observed in FLiNaK, but the chemical attack was found to be less aggressive. Sulfamate Ni electroplating and Mo plasma spraying of Fe-Ni-Cr alloy coupons was investigated to mitigate Cr dissolution. A chemical vapor deposited pyrolytic carbon and SiC coating was also investigated to protect the C/SiSiC composites. Results indicate that Ni-plating has the potential to provide protection against alloy corrosion in molten fluoride salts. Furthermore, the presence of a chromium-oxide interlayer at the interface of the Ni-plating and alloy substrate can further improve the efficacy of the Ni-plating. The pyrolytic carbon and SiC coating on the C/SiSiC composites

  3. Radiation and phase change of lithium fluoride in an annulus

    NASA Technical Reports Server (NTRS)

    Lund, Kurt O.

    1993-01-01

    A one-dimensional thermal model is developed to evaluate the effect of radiation on the phase change of lithium-fluoride (LiF) in an annular canister under gravitational and microgravitational conditions. Specified heat flux at the outer wall of the canister models focused solar flux; adiabatic and convective conditions are considered for the inner wall. A two-band radiation model is used for the combined-mode heat transfer within the canister, and LiF optical properties relate metal surface properties in vacuum to those in LiF. For axial gravitational conditions, the liquid LiF remains in contact with the two bounding walls, whereas a void gap is used at the outer wall to model possible microgravitational conditions. For the adiabatic cases, exact integrals are obtained for the time required for complete melting of the LiF. Melting was found to occur primarily from the outer wall in the 1-g model, whereas it occurred primarily from the inner wall in the mu-g model. For the convective cases, partially melted steady-state conditions and fully melted conditions are determined to depend on the source flux level, with radiation extending the melting times.

  4. Hot filament technique for measuring the thermal conductivity of molten lithium fluoride

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Perry, William D.

    1990-01-01

    Molten salts, such as lithium fluoride, are attractive candidates for thermal energy storage in solar dynamic space power systems because of their high latent heat of fusion. However, these same salts have poor thermal conductivities which inhibit the transfer of heat into the solid phase and out of the liquid phase. One concept for improving the thermal conductivity of the thermal energy storage system is to add a conductive filler material to the molten salt. High thermal conductivity pitch-based graphite fibers are being considered for this application. Although there is some information available on the thermal conductivity of lithium fluoride solid, there is very little information on lithium fluoride liquid, and no information on molten salt graphite fiber composites. This paper describes a hot filament technique for determining the thermal conductivity of molten salts. The hot filament technique was used to find the thermal conductivity of molten lithium fluoride at 930 C, and the thermal conductivity values ranged from 1.2 to 1.6 W/mK. These values are comparable to the slightly larger value of 5.0 W/mK for lithium fluoride solid. In addition, two molten salt graphite fiber composites were characterized with the hot filament technique and these results are also presented.

  5. Nuclear quantum effects in water exchange around lithium and fluoride ions.

    PubMed

    Wilkins, David M; Manolopoulos, David E; Dang, Liem X

    2015-02-14

    We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the exchange processes are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due to the lighter mass of lithium and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium.

  6. Nuclear quantum effects in water exchange around lithium and fluoride ions

    SciTech Connect

    Wilkins, David M.; Manolopoulos, David E.; Dang, Liem X.

    2015-02-14

    We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the exchange processes are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due to the lighter mass of lithium and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium.

  7. Nuclear quantum effects in water exchange around lithium and fluoride ions

    SciTech Connect

    Wilkins, David M.; Manolopoulos, David; Dang, Liem X.

    2015-02-14

    We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the water exchange reactions are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due to the lighter mass of lithium, and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium. LXD was supported by US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.

  8. Observations of the freeze/thaw performance of lithium fluoride by motion picture photography

    NASA Technical Reports Server (NTRS)

    Jaworske, D. A.; Perry, W. D.

    1991-01-01

    To gain direct observation of the molten salt phase change, a novel containerless technique was developed where the high surface tension of lithium fluoride was used to suspend a bead of the molten salt inside a specially designed wire cage. By varying the current passing through the wire, the cage also served as a variable heat source. In this way, the freeze/thaw performance of the lithium fluoride could be photographed by motion picture photography without the influence of container walls. The motion picture photography of the lithium fluoride sample revealed several zones during the phase change, a solid zone and a liquid zone, as expected, and a slush zone that was predicted by thermal analysis modeling.

  9. Crystallization, Optical and Chemical Properties of Fluoride Glasses

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.

    1985-01-01

    Fluoride glasses have great promise as infrared optical components, especially fibers, because they are transparent to 8 micrometers and higher. In order to optimize properties, different glass compositions are needed. Some are hard to form in a container, and may possibly be formable in a containerless furnace. Understanding of crystallization with and without a container could lead to glasses with optimum properties. Chemical durability (attack by water) can limit or extend the applicability of fluoride glasses. Progress to date is given.

  10. Zero-gravity growth of a sodium chloride-lithium fluoride eutectic mixture

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Yeh, C. W.; Yue, B. K.

    1982-01-01

    Continuous and discontinuous lithium fluoride fibers embedded in a sodium chloride matrix were produced in space and on Earth, respectively. The production of continuous fibers in a eutectic mixture was attributed to the absence of convective current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and Earth-grown ingots were made with a light microscope and a spectrometer. It was found that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of lithium fluoride fibers along the growth direction.

  11. Effects of light exposure on irradiated barium fluoride crystals

    SciTech Connect

    Wuest, C.R.; Mauger, G.J.

    1993-04-20

    Small barium fluoride crystals have been irradiated using cobalt-60 gamma rays under various illumination conditions to establish the effect of photo-bleaching of the radiation-induced color centers. This paper describes results of a few different experiments conducted at LLNL over the past few weeks.

  12. Mechanical and optical response of [100] lithium fluoride to multi-megabar dynamic pressures

    NASA Astrophysics Data System (ADS)

    Davis, Jean-Paul; Knudson, Marcus D.; Shulenburger, Luke; Crockett, Scott D.

    2016-10-01

    An understanding of the mechanical and optical properties of lithium fluoride (LiF) is essential to its use as a transparent tamper and window for dynamic materials experiments. In order to improve models for this material, we applied iterative Lagrangian analysis to ten independent sets of data from magnetically driven planar shockless compression experiments on single crystal [100] LiF to pressures as high as 350 GPa. We found that the compression response disagreed with a prevalent tabular equation of state for LiF that is commonly used to interpret shockless compression experiments. We also present complementary data from ab initio calculations performed using the diffusion quantum Monte Carlo method. The agreement between these two data sets lends confidence to our interpretation. In order to aid in future experimental analysis, we have modified the tabular equation of state to match the new data. We have also extended knowledge of the optical properties of LiF via shock-compression and shockless compression experiments, refining the transmissibility limit, measuring the refractive index to ˜300 GPa, and confirming the nonlinear dependence of the refractive index on density. We present a new model for the refractive index of LiF that includes temperature dependence and describe a procedure for correcting apparent velocity to true velocity for dynamic compression experiments.

  13. Mechanical and optical response of [100] lithium fluoride to multi-megabar dynamic pressures

    SciTech Connect

    Davis, Jean -Paul; Knudson, Marcus D.; Shulenburger, Luke; Crockett, Scott D.

    2016-10-26

    An understanding of the mechanical and optical properties of lithium fluoride (LiF) is essential to its use as a transparent tamper and window for dynamic materials experiments. In order to improve models for this material, we applied iterative Lagrangian analysis to ten independent sets of data from magnetically driven planar shockless compression experiments on single crystal [100] LiF to pressures as high as 350 GPa. We found that the compression response disagreed with a prevalent tabular equation of state for LiF that is commonly used to interpret shockless compression experiments. We also present complementary data from ab initio calculations performed using the diffusion quantum Monte Carlo method. The agreement between these two data sets lends confidence to our interpretation. In order to aid in future experimental analysis, we have modified the tabular equation of state to match the new data. We have also extended knowledge of the optical properties of LiF via shock-compression and shockless compression experiments, refining the transmissibility limit, measuring the refractive index to ~300 GPa, and confirming the nonlinear dependence of the refractive index on density. Lastly, we present a new model for the refractive index of LiF that includes temperature dependence and describe a procedure for correcting apparent velocity to true velocity for dynamic compression experiments.

  14. Mechanical and optical response of [100] lithium fluoride to multi-megabar dynamic pressures

    DOE PAGES

    Davis, Jean -Paul; Knudson, Marcus D.; Shulenburger, Luke; ...

    2016-10-26

    An understanding of the mechanical and optical properties of lithium fluoride (LiF) is essential to its use as a transparent tamper and window for dynamic materials experiments. In order to improve models for this material, we applied iterative Lagrangian analysis to ten independent sets of data from magnetically driven planar shockless compression experiments on single crystal [100] LiF to pressures as high as 350 GPa. We found that the compression response disagreed with a prevalent tabular equation of state for LiF that is commonly used to interpret shockless compression experiments. We also present complementary data from ab initio calculations performedmore » using the diffusion quantum Monte Carlo method. The agreement between these two data sets lends confidence to our interpretation. In order to aid in future experimental analysis, we have modified the tabular equation of state to match the new data. We have also extended knowledge of the optical properties of LiF via shock-compression and shockless compression experiments, refining the transmissibility limit, measuring the refractive index to ~300 GPa, and confirming the nonlinear dependence of the refractive index on density. Lastly, we present a new model for the refractive index of LiF that includes temperature dependence and describe a procedure for correcting apparent velocity to true velocity for dynamic compression experiments.« less

  15. Mechanical response of lithium fluoride under off-principal dynamic shock-ramp loading

    DOE PAGES

    Seagle, Christopher T.; Davis, Jean-Paul; Knudson, Marcus D.

    2016-10-26

    Single crystal lithium fluoride (LiF), oriented [100], was shock loaded and subsequently shocklessly compressed in two experiments at the Z Machine. We employed velocimetry measurements in order to obtain an impactor velocity, shock transit times, and in-situ particle velocities for LiF samples up to ~1.8 mm thick. We also performed a dual thickness Lagrangian analysis on the in-situ velocimetry data to obtain the mechanical response along the loading path of these experiments. Finally, we observed an elastic response on one experiment during initial shockless compression from 100 GPa before yielding. The relatively large thickness differences utilized for the dual samplemore » analyses (up to ~1.8 mm) combined with a relative timing accuracy of ~0.2 ns resulted in an uncertainty of less than 1% on density and stress at ~200 GPa peak loading on one experiment and <4% on peak loading at ~330 GPa for another. The stress-density analyses from these experiments compare favorably with recent equation of state models for LiF.« less

  16. Mechanical response of lithium fluoride under off-principal dynamic shock-ramp loading

    SciTech Connect

    Seagle, Christopher T.; Davis, Jean-Paul; Knudson, Marcus D.

    2016-10-26

    Single crystal lithium fluoride (LiF), oriented [100], was shock loaded and subsequently shocklessly compressed in two experiments at the Z Machine. We employed velocimetry measurements in order to obtain an impactor velocity, shock transit times, and in-situ particle velocities for LiF samples up to ~1.8 mm thick. We also performed a dual thickness Lagrangian analysis on the in-situ velocimetry data to obtain the mechanical response along the loading path of these experiments. Finally, we observed an elastic response on one experiment during initial shockless compression from 100 GPa before yielding. The relatively large thickness differences utilized for the dual sample analyses (up to ~1.8 mm) combined with a relative timing accuracy of ~0.2 ns resulted in an uncertainty of less than 1% on density and stress at ~200 GPa peak loading on one experiment and <4% on peak loading at ~330 GPa for another. The stress-density analyses from these experiments compare favorably with recent equation of state models for LiF.

  17. Test beam results of a cerium fluoride crystal matrix

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Bourotte, J.; Beckers, T.; Chipaux, M.; Commichau, V.; Dafinei, I.; Depasse, P.; Djambazov, L.; Dydak, U.; El Mamouni, H.; Fay, J.; Felcini, M.; Goyot, M.; Haguenauer, M.; Hillemans, H.; Hofer, H.; Ille, B.; Kirn, T.; Kryn, D.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Martin, J. P.; Maurelli, G.; Mattioli, M.; Melnikov, I.; Nessi-Tedaldi, F.; Pacciani, L.; Pirro, S.; Raghavan, R.; Ren, D.; Reynaud, M.; Röser, U.; Sahuc, P.; Schmitz, D.; Schneegans, M.; Schwenke, J.; Soric, I.; Viertel, G.; von Gunten, H. P.; Walder, J. P.; Waldmeier-Wicki, S.

    1995-11-01

    A Cerium Fluoride matrix of 3 × 3 towers with Silicon photodiode readout has been tested in electron and pion beams from 10 to 150 GeV energy. The matrix was assembled with a selection of crystals out of a total of over 40 large crystals (up to 20 cm long and 3 cm × 3 cm in cross section) from various producers. Despite less than optimal geometry and crystal quality, an energy resolution of 0.5% for energies ≥ 50 GeV has been obtained. Fast shaping amplifier prototypes were tested and their performance was found to be appropriate for operation in an LHC-like environment.

  18. Ytterbium-doped borate fluoride laser crystals and lasers

    DOEpatents

    Schaffers, Kathleen I.; DeLoach, Laura D.; Payne, Stephen A.; Keszler, Douglas A.

    1997-01-01

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM'(BO.sub.3)F, where M, M' are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO.sub.3 F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator.

  19. Ytterbium-doped borate fluoride laser crystals and lasers

    DOEpatents

    Schaffers, K.I.; DeLoach, L.D.; Payne, S.A.; Keszler, D.A.

    1997-10-14

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM{prime}(BO{sub 3})F, where M, M{prime} are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO{sub 3}F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator. 6 figs.

  20. Lithium-cation conductivity and crystal structure of lithium diphosphate

    SciTech Connect

    Voronin, V.I.; Sherstobitova, E.A.; Blatov, V.A.; Shekhtman, G.Sh.

    2014-03-15

    The electrical conductivity of lithium diphosphate Li{sub 4}P{sub 2}O{sub 7} has been measured and jump-like increasing of ionic conductivity at 913 K has been found. The crystal structure of Li{sub 4}P{sub 2}O{sub 7} has been refined using high temperature neutron diffraction at 300–1050 K. At 913 K low temperature triclinic form of Li{sub 4}P{sub 2}O{sub 7} transforms into high temperature monoclinic one, space group P2{sub 1}/n, a=8.8261(4) Å, b=5.2028(4) Å, c=13.3119(2) Å, β=104.372(6)°. The migration maps of Li{sup +} cations based on experimental data implemented into program package TOPOS have been explored. It was found that lithium cations in both low- and high temperature forms of Li{sub 4}P{sub 2}O{sub 7} migrate in three dimensions. Cross sections of the migrations channels extend as the temperature rises, but at the phase transition point have a sharp growth showing a strong “crystal structure – ion conductivity” correlation. -- Graphical abstract: Crystal structure of Li{sub 4}P{sub 2}O{sub 7} at 950 K. Red balls represent oxygen atoms; black lines show Li{sup +} ion migration channels in the layers perpendicular to [001] direction. Highlights: • Structure of Li{sub 4}P{sub 2}O{sub 7} has been refined using high temperature neutron diffraction. • At 913 K triclinic form of Li{sub 4}P{sub 2}O{sub 7} transforms into high temperature monoclinic one. • The migration maps of Li{sup +} implemented into program package TOPOS have been explored. • Cross sections of the migrations channels at the phase transition have a sharp growth.

  1. Quantum monte carlo study of the energetics of small hydrogenated and fluoride lithium clusters.

    PubMed

    Moreira, N L; Brito, B G A; Rabelo, J N Teixeira; Cândido, Ladir

    2016-06-30

    An investigation of the energetics of small lithium clusters doped either with a hydrogen or with a fluorine atom as a function of the number of lithium atoms using fixed-node diffusion quantum Monte Carlo (DMC) simulation is reported. It is found that the binding energy (BE) for the doped clusters increases in absolute values leading to a more stable system than for the pure ones in excellent agreement with available experimental measurements. The BE increases for pure, remains almost constant for hydrogenated, and decreases rapidly toward the bulk lithium for the fluoride as a function of the number of lithium atoms in the clusters. The BE, dissociation energy as well as the second difference in energy display a pronounced odd-even oscillation with the number of lithium atoms. The electron correlation inverts the odd-even oscillation pattern for the doped in comparison with the pure clusters and has an impact of 29%-83% to the BE being higher in the pure cluster followed by the hydrogenated and then by the fluoride. The dissociation energy and the second difference in energy indicate that the doped cluster Li3 H is the most stable whereas among the pure ones the more stable are Li2 , Li4 , and Li6 . The electron correlation energy is crucial for the stabilization of Li3 H. © 2016 Wiley Periodicals, Inc.

  2. Improving lithium therapeutics by crystal engineering of novel ionic cocrystals.

    PubMed

    Smith, Adam J; Kim, Seol-Hee; Duggirala, Naga K; Jin, Jingji; Wojtas, Lukasz; Ehrhart, Jared; Giunta, Brian; Tan, Jun; Zaworotko, Michael J; Shytle, R Douglas

    2013-12-02

    Current United States Food and Drug Administration (FDA)-approved lithium salts are plagued with a narrow therapeutic window. Recent attempts to find alternative drugs have identified new chemical entities, but lithium's polypharmacological mechanisms for treating neuropsychiatric disorders are highly debated and are not yet matched. Thus, re-engineering current lithium solid forms in order to optimize performance represents a low cost and low risk approach to the desired therapeutic outcome. In this contribution, we employed a crystal engineering strategy to synthesize the first ionic cocrystals (ICCs) of lithium salts with organic anions. We are unaware of any previous studies that have assessed the biological efficacy of any ICCs, and encouragingly we found that the new speciation did not negatively affect established bioactivities of lithium. We also observed that lithium ICCs exhibit modulated pharmacokinetics compared to lithium carbonate. Indeed, the studies detailed herein represent an important advancement in a crystal engineering approach to a new generation of lithium therapeutics.

  3. F 3 - molecular ions in fluoride crystals

    NASA Astrophysics Data System (ADS)

    Radzhabov, E. A.

    2016-02-01

    The UV absorption spectra of F 3 - molecular ions in LaF3, SrF2, CaF2, and BaF2 crystals doped with rare-earth elements are studied. Comparison of radiation-colored and additively colored crystals reveals the absorption bands of F 3 - hole centers in the region near 6 eV. Nonempirical calculations of optical transitions agree well with experimental results.

  4. Spectral Diversity Crystalline Fluoride Lasers,

    DTIC Science & Technology

    1981-01-01

    2 4.-. i1.34 I R TUNABLE Table IX XeF Pumoe TM3 +: YLF :1 .Tm:YLF exhibits nearly ideal parameters for high energy operation aa3x10-20cm 2 ESAT 0cm e...host crystal, lithium yttrium fluoride, LiYF*4 ( YLF )" 1..0 Introductin Within the realm of crystalline laser materials,. the class of fluorides...on the host crystal, lithium yttrium fluoride, LiYF4 - often shortened as YLF . Tables I and 12 show the mechanical, thermal, and optical properties

  5. Crystal nucleation in lithium borate glass

    NASA Technical Reports Server (NTRS)

    Smith, Gary L.; Neilson, George F.; Weinberg, Michael C.

    1988-01-01

    Crystal nucleation measurements were made on three lithium borate compositions in the vicinity of Li2O-2Br2O3. All nucleation measurements were performed at 500 C. Certain aspects of the nucleation behavior indicated (tentatively) that it proceeded by a homogeneous mechanism. The steady state nucleation rate was observed to have the largest value when the Li2O concentration was slightly in excess of the diborate composition. The change in nucleation rate with composition is controlled by the variation of viscosity as well as the change in free energy with composition. The variation of nucleation rate is explained qualitatively in these terms.

  6. Optical properties of lithium niobate single crystals

    NASA Astrophysics Data System (ADS)

    Palatnikov, M. N.; Sidorov, N. V.; Biryukova, I. V.; Kalinnikov, V. T.; Bormanis, K.

    2005-01-01

    Studies of thermal and -irradiation effects on the optical properties in congruous lithium niobate single crystals containing Y, Mg, Gd, B, and Zn dopants including samples with double dopants Y, Mg and Gd, Mg are reported. Formation of defects at irradiation and thermal treatment of the samples is explored by electron absorption spectra. Considerable increase of absorption with the dose of -radiation is observed at 500 nm. The changes of absorption examined under different conditions are explained by creation and destruction of Nb4+ defects.

  7. Spectroscopic Investigation of Ce(3+) Doped Fluoride Crystals

    NASA Technical Reports Server (NTRS)

    Reinhart, Donald H.; Armagan, Guzin; Marsh, Waverly; Barnes, James; Chai, B. H. T.

    1995-01-01

    Doping of the trivalent rare-earth cerium ion into fluoride crystals is of interest in producing turnable ultra-violet solid state lasers. These lasers are desirable for many applications in medicine, industry, and scientific research, including remote sensing. High absorption and stimulated emission cross sections of the dipole allowed 4f-5d transitions show promise in cerium as a laser ion in crystals. Several research groups have already reported the observation of stimulated emission of cerium in LiYF4, LiSrAlF6, and LiCaAlF6. However, the color center formation in the crystals due to the excited state absorption of ultra-violet pump light adds difficulty to achieving laser action. We have investigated the spectroscopic properties of cerium such as absorption and emission spectra, and lifetimes in four different fluoride crystals, including LiCaAlF6, LiSrAlF6, KyF4 and LiYF4. We have derived the polarized absorption and stimulated emission cross sections from transmission and fluorescence emission measurements for each of the host crystals. we have measured the lifetime of the lowest 5d level; moreover, investigated the temperature dependence of this lifetime and color center formation. Our results on absorption and stimulated emission cross sections for LiCaAlF6 and LiSrAlF6 are similar to the results already published.

  8. Magnesium oxide doping reduces acoustic wave attenuation in lithium metatantalate and lithium metaniobate crystals

    NASA Technical Reports Server (NTRS)

    Croft, W.; Damon, R.; Kedzie, R.; Kestigian, M.; Smith, A.; Worley, J.

    1970-01-01

    Single crystals of lithium metatantalate and lithium metaniobate, grown from melts having different stoichiometries and different amounts of magnesium oxide, show that doping lowers temperature-independent portion of attenuation of acoustic waves. Doped crystals possess optical properties well suited for electro-optical and photoelastic applications.

  9. Shrinkage void formation and its effect on freeze and thaw processes of lithium and lithium-fluoride for space applications

    NASA Technical Reports Server (NTRS)

    Yang, Jae Y.; El-Genk, Mohamed S.

    1991-01-01

    The effects of shrinkage void forming during freezing of lithium and lithium fluoride on subsequent thaw processes are investigated using a numerical scheme that is based on a single (solid/liquid) cell approach. Results show that a void forming at the wall appreciably reduces the solid-liquid interface velocity, during both freeze and thaw, and causes a substantial rise in the wall temperature during thaw. However, in the case of Li, the maximum wall temperature was much lower than the melting temperature of PWC-11, which is used as the structure material in the SP-100 system. Hence, it is concluded that a formation of hot spots is unlikely during the startup or restart of the SP-100 system.

  10. An investigation of voids formation mechanisms and their effects on freeze and thaw processes of lithium and lithium fluoride

    NASA Technical Reports Server (NTRS)

    El-Genk, Mohamed S.; Yang, Jae-Young

    1991-01-01

    The mechanisms of void formation during the cooldown and freezing of lithium coolant within the primary loop of SP-100 type systems are investigated. These mechanisms are: (1) homogeneous nucleation; (2) heterogeneous nucleation; (3) normal segregation of helium gas dissolved in liquid lithium; and (4) shrinkage of lithium during freezing. To evaluate the void formation potential due to segregation, a numerical scheme that couples the freezing and mass diffusion processes in both the solid and liquid regions is developed. The results indicated that the formation of He bubbles is unlikely by either homogeneous or heterogeneous nucleation during the cooldown process. However, homogeneous nucleation of He bubbles following the segregation of dissolved He in liquid lithium ahead of the solid-liquid interface is likely to occur. Results also show that total volume of He void is insignificant when compared to that of shrinkage voids. In viewing this, the subsequent research focuses on the effects of shrinkage void forming during freezing of lithium on subsequent thaw processes are investigated using a numerical scheme that is based on a single (solid/liquid) cell approach. The cases of lithium-fluoride are also investigated to show the effect of larger volume shrinkage upon freezing on the freeze and thaw processes. Results show that a void forming at the wall appreciably reduces the solid-liquid interface velocity, during both freeze and thaw, and causes a substantial rise in the wall temperature during thaw. However, in the case of Li, the maximum wall temperature was much lower than the melting temperature of PWC-11, which is used as the structure material in the SP-100 system. Hence, it is included that a formation of hot spots is unlikely during the startup or restart of the SP-100 system.

  11. Carbon Nanohorns Carried Iron Fluoride Nanocomposite with ultrahigh rate lithium ion storage properties

    PubMed Central

    Fan, Lishuang; Li, Bingjiang; Zhang, Naiqing; Sun, Kening

    2015-01-01

    Novel hierarchical carbon nanohorns (CNHs) carried iron fluoride nanocomposites have been constructed by direct growth of FeF3·0.33H2O nanoparticles on CNHs. In the FeF3·0.33H2O@CNHs nanocomposite, the mesopore CNHs play the role as conductive matrix and robust carrier to support the FeF3·0.33H2O nanoparticles. The intimate conductive contact between the two components can build up an express way of electron transfer for rapid Li+ insertion/extraction. The CNHs can not only suppress the growth and agglomeration of FeF3·0.33H2O during the crystallization process, but also sever as an “elastic confinement” to support FeF3·0.33H2O. As was to be expected, the hierarchical FeF3·0.33H2O@CNHs nanocomposite exhibits impressive rate capability and excellent cycle performance. Markedly, the nanocomposite proves stable, ultrahigh rate lithium ion storage properties of 81 mAh g−1 at charge/discharge rate of 50 C (a discharge/charge process only takes 72 s). The integration of high electron conductivity, confined nano sized FeF3·0.33H2O (~5 nm), hierarchical mesopores CNHs and the “elastic confinement” support, the FeF3·0.33H2O@CNHs nanocomposite demonstrates excellent ultrahigh rate capability and good cycling properties. PMID:26173994

  12. Viscosity of molten lithium, thorium and beryllium fluorides mixtures

    NASA Astrophysics Data System (ADS)

    Merzlyakov, Alexander V.; Ignatiev, Victor V.; Abalin, Sergei S.

    2011-12-01

    Considering development of Molten Salt Fast Reactor (MSFR) concept, following Molten Salt fluorides mixtures have been chosen as an object for viscosity studies in this work (in mol%): 78LiF-22ThF 4; 71LiF-27ThF 4-2BeF 2 and 75LiF-20ThF 4-5BeF 2. Additionally, the effect of the 3 mol% CeF 3 additives on viscosity of the molten 75LiF-20ThF 4-5BeF 2 (mol%) salt mixture has been investigated experimentally. The method of torsional oscillations of cylindrical crucible filled by molten fluorides mixture has been chosen for kinematic viscosity measurement at temperatures up to 800-850 °C. In temperature ranges, where melts behave as normal liquids, dependences on viscosity vs. temperature are received: ν = А exp [B/T(K)], where ν - kinematic viscosity, m 2/s; T - temperature, K. The kinematic viscosity Rout mean squares (RMS) estimated in the assumption about dispersion homoscedasticity is (0.04-0.12) × 10 -6 (m 2/s). Discrepancies left in the data of viscosity for molten mixtures of LiF, BeF 2 and ThF 4 received by different researchers need further investigations in this area to be continued.

  13. Efficient holmium:yttrium lithium fluoride laser longitudinally pumped by a semiconductor laser array

    NASA Technical Reports Server (NTRS)

    Hemmati, H.

    1987-01-01

    Optical pumping of a holmium:yttrium lithium floride (Ho:YLF) crystal with a 790-nm continuous-wave diode-laser array has generated 56 mW of 2.1-micron laser radiation with an optical-to-optical conversion slope efficiency of 33 percent while the crystal temperature is held at 77 K. The lasing threshold occurs at 7 mW of input power, and laser operation continues up to a crystal temperature of 124 K.

  14. An experimental analysis of a doped lithium fluoride direct absorption solar receiver

    NASA Technical Reports Server (NTRS)

    Kesseli, James; Pollak, Tom; Lacy, Dovie

    1988-01-01

    An experimental analysis of two key elements of a direct absorption solar receiver for use with Brayton solar dynamic systems was conducted. Experimental data are presented on LiF crystals doped with dysprosium, samarium, and cobalt fluorides. In addition, a simulation of the cavity/window environment was performed and a posttest inspection was conducted to evaluate chemical reactivity, transmissivity, and condensation rate.

  15. X-ray refractive-index measurement in silicon and lithium fluoride

    NASA Astrophysics Data System (ADS)

    Deutsch, Moshe; Hart, Michael

    1984-07-01

    The refractive indices n of silicon and lithium fluoride were measured noninterferometrically with Mo Kα¯ and Ag Kα¯ x rays to a sub-part-per-billion accuracy. This high accuracy allows experimental determination of the real dispersion correction f' to +/-2 millielectron accuracy. The f' values obtained are in excellent agreement with the best interferometric measurements, part of which are less accurate than the present results. The predictions of both the Cromer-Liberman and the modified Hönl theories are found to deviate significantly from the measured f' values, thus indicating the need for modification of the wave functions or, more likely, the exchange potential used.

  16. Polyethylene-supported polyvinylidene fluoride-cellulose acetate butyrate blended polymer electrolyte for lithium ion battery

    NASA Astrophysics Data System (ADS)

    Liu, Jiansheng; Li, Weishan; Zuo, Xiaoxi; Liu, Shengqi; Li, Zhao

    2013-03-01

    The polyethylene (PE)-supported polymer membranes based on the blended polyvinylidene fluoride (PVDF) and cellulose acetate butyrate (CAB) are prepared for gel polymer electrolyte (GPE) of lithium ion battery. The performances of the prepared membranes and the resulting GPEs are investigated by scanning electron microscopy, electrochemical impedance spectroscopy, linear potential sweep, and charge-discharge test. The effect of the ratio of PVDF to CAB on the performance of the prepared membranes is considered. It is found that the GPE based on the blended polymer with PVDF:CAB = 2:1 (in weight) has the largest ionic conductivity (2.48 × 10-3 S cm-1) and shows good compatibility with anode and cathode of lithium ion battery. The LiCoO2/graphite battery using this GPE exhibits superior cyclic stability at room temperature, storage performance at elevated temperature, and rate performance.

  17. Fluoride Inhibition of Enolase: Crystal Structure and Thermodynamics

    SciTech Connect

    Qin, Jie; Chai, Geqing; Brewer, John M.; Lovelace, Leslie L.; Lebioda, Lukasz

    2010-12-03

    Enolase is a dimeric metal-activated metalloenzyme which uses two magnesium ions per subunit: the strongly bound conformational ion and the catalytic ion that binds to the enzyme-substrate complex inducing catalysis. The crystal structure of the human neuronal enolase-Mg{sub 2}F{sub 2}P{sub i} complex (enolase fluoride/phosphate inhibitory complex, EFPIC) determined at 1.36 {angstrom} resolution shows that the combination of anions effectively mimics an intermediate state in catalysis. The phosphate ion binds in the same site as the phosphate group of the substrate/product, 2-phospho-d-glycerate/phosphoenolpyruvate, and induces binding of the catalytic Mg{sup 2+} ion. One fluoride ion bridges the structural and catalytic magnesium ions while the other interacts with the structural magnesium ion and the ammonio groups of Lys 342 and Lys 393. These fluoride ion positions correspond closely to the positions of the oxygen atoms of the substrate's carboxylate moiety. To relate structural changes resulting from fluoride, phosphate, and magnesium ions binding to those that are induced by phosphate and magnesium ions alone, we also determined the structure of the human neuronal enolase-Mg{sub 2}Pi complex (enolase phosphate inhibitory complex, EPIC) at 1.92 {angstrom} resolution. It shows the closed conformation in one subunit and a mixture of open and semiclosed conformations in the other. The EPFIC dimer is essentially symmetric while the EPIC dimer is asymmetric. Isothermal titration calorimetry data confirmed binding of four fluoride ions per dimer and yielded K{sub b} values of 7.5 x 10{sup 5} {+-} 1.3 x 10{sup 5}, 1.2 x 10{sup 5} {+-} 0.2 x 10{sup 5}, 8.6 x 10{sup 4} {+-} 1.6 x 10{sup 4}, and 1.6 x 10{sup 4} {+-} 0.7 x 10{sup 4} M{sup -1}. The different binding constants indicate negative cooperativity between the subunits; the asymmetry of EPIC supports such an interpretation.

  18. Effects of fluoride on the interactions between amelogenin and apatite crystals.

    PubMed

    Tanimoto, K; Le, T; Zhu, L; Chen, J; Featherstone, J D B; Li, W; DenBesten, P

    2008-01-01

    Fluorosed enamel is more porous and less mineralized, possibly related to altered amelogenin-modulated crystal growth. The purpose of this study was to examine the role of fluoride in interactions between amelogenin and apatite crystals. Recombinant human amelogenin (rh174) was bound to carbonated hydroxyapatite containing various amounts of fluoride, and analyzed by protein assay, SDS PAGE, and AFM. Interactions between rh174 and fluoride were assayed by isothermal titration calorimetry (ITC). The initial binding rate of rh174, as well as total amount of rh174 bound to fluoride-containing carbonated hydroxyapatite, was greater than that in the control carbonated hydroxyapatite. Fluoride in solution at physiologic (5.3 micromolar, or 0.1 ppm) concentrations showed no significant effect on binding, but higher fluoride levels significantly decreased protein binding. ITC showed no interactions between fluoride and rh174. These results suggest that fluoride incorporation into the crystal lattice alters the crystal surface to enhance amelogenin binding, with no direct interactions between fluoride and amelogenin.

  19. Fluoride crystals: materials for near-infrared solid state lasers

    NASA Astrophysics Data System (ADS)

    Parisi, Daniela; Veronesi, Stefano; Volpi, Azzurra; Gemmi, Mauro; Tonelli, Mauro; Cassanho, Arlete; Jenssen, Hans P.

    2013-07-01

    In this work we present an overview of the best 2μm laser results obtained in Tm-doped fluoride hosts LiYF4(YLF), LiLuF4 (LLF) and BaY2F8 (BYF) and we report on the growth, spectroscopy and first laser test emission of a novel mixed material BaYLuF8 (BYLF), interesting as a variant of BYF material with a partial substitution of Y3+ ions by Lu3+. The novel host is interesting mainly because indications are that the mixed crystal would be sturdier than BYF. The addition of Lutetium would improve the thermo-mechanical properties going into the direction of high power applications, as suggest from works on YLF and its isomorph LLF. A detailed description of Czochralski growth of fluoride laser materials is provided, focusing on the growth parameters of the novel BYLF:Tm3+12% material grown. With regard of spectroscopy analysis, we report on the results obtained with BYLF host. Detailed absorption, fluorescence and lifetime measurements have been performed focusing on the 3H4 and 3F4 manifolds, the pumping and upper laser level. Moreover diode pumped CW laser emission at 2 μm has been achieved in BYLF: Tm3+12% sample obtaining a slope efficiency of about 28% with respect to the absorbed power.

  20. Broadband X-ray edge-enhancement imaging of a boron fibre on lithium fluoride thin film detector

    NASA Astrophysics Data System (ADS)

    Nichelatti, E.; Bonfigli, F.; Vincenti, M. A.; Cecilia, A.; Vagovič, P.; Baumbach, T.; Montereali, R. M.

    2016-10-01

    The white beam (∼6-80 keV) available at the TopoTomo X-ray beamline of the ANKA synchrotron facility (KIT, Karlsruhe, Germany) was used to perform edge-enhancement imaging tests on lithium fluoride radiation detectors. The diffracted X-ray image of a microscopic boron fibre, consisting of tungsten wire wrapped by boron cladding, was projected onto lithium fluoride thin films placed at several distances, from contact to 1 m . X-ray photons cause the local formation of primary and aggregate colour centres in lithium fluoride; these latter, once illuminated under blue light, luminesce forming visible-light patterns-acquired by a confocal laser scanning microscope-that reproduce the intensity of the X-ray diffracted images. The tests demonstrated the excellent performances of lithium fluoride films as radiation detectors at the investigated photon energies. The experimental results are here discussed and compared with those calculated with a model that takes into account all the processes that concern image formation, storing and readout.

  1. Conversion Reaction Mechanisms in Lithium Ion Batteries: Study of the Binary Metal Fluoride Electrodes

    SciTech Connect

    Wang, Feng; Robert, Rosa; Chernova, Natasha A.; Pereira, Nathalie; Omenya, Fredrick; Badway, Fadwa; Hua, Xiao; Ruotolo, Michael; Zhang, Ruigang; Wu, Lijun; Volkov, Vyacheslav; Su, Dong; Key, Baris; Whittingham, M. Stanley; Grey, Clare P.; Amatucci, Glenn G.; Zhu, Yimei; Graetz, Jason

    2015-10-15

    Materials that undergo a conversion reaction with lithium (e.g., metal fluorides MF{sub 2}: M = Fe, Cu, ...) often accommodate more than one Li atom per transition-metal cation, and are promising candidates for high-capacity cathodes for lithium ion batteries. However, little is known about the mechanisms involved in the conversion process, the origins of the large polarization during electrochemical cycling, and why some materials are reversible (e.g., FeF{sub 2}) while others are not (e.g., CuF{sub 2}). In this study, we investigated the conversion reaction of binary metal fluorides, FeF{sub 2} and CuF{sub 2}, using a series of local and bulk probes to better understand the mechanisms underlying their contrasting electrochemical behavior. X-ray pair-distribution-function and magnetization measurements were used to determine changes in short-range ordering, particle size and microstructure, while high-resolution transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) were used to measure the atomic-level structure of individual particles and map the phase distribution in the initial and fully lithiated electrodes. Both FeF{sub 2} and CuF{sub 2} react with lithium via a direct conversion process with no intercalation step, but there are differences in the conversion process and final phase distribution. During the reaction of Li{sup +} with FeF{sub 2}, small metallic iron nanoparticles (<5 nm in diameter) nucleate in close proximity to the converted LiF phase, as a result of the low diffusivity of iron. The iron nanoparticles are interconnected and form a bicontinuous network, which provides a pathway for local electron transport through the insulating LiF phase. In addition, the massive interface formed between nanoscale solid phases provides a pathway for ionic transport during the conversion process. These results offer the first experimental evidence explaining the origins of the high lithium reversibility in FeF{sub 2}. In contrast

  2. New UV instrumentation enabled by enhanced broadband reflectivity lithium fluoride coatings

    NASA Astrophysics Data System (ADS)

    Fleming, Brian T.; Quijada, Manuel A.; France, Kevin; Hoadley, Keri; Del Hoyo, Javier; Kruczek, Nicholas

    2015-08-01

    We present the results of a preliminary aging study of new enhanced broadband reflectivity lithium fluoride mirror coatings under development at the thin films laboratory at GSFC. These coatings have demonstrated greater than 80% reflectivity from the Lyman ultraviolet (~1020 Å) to the optical, and have the potential to revolutionize far-ultraviolet instrument design and capabilities. This work is part of a concept study in preparation for the fight qualification of these new coatings in a working astronomical environment. We outline the goals for TRL advancement, and discuss the instrument capabilities enabled by these high reflectivity broadband coatings on potential future space missions. We also present the early design of the first space experiment to utilize these coatings, the proposed University of Colorado sounding rocket payload SISTINE, and show how these new coatings make the science goals of SISTINE attainable on a suborbital platform.

  3. Organic photovoltaic devices with the bilayer cathode interfacial structure of pyromellitic dianhydride and lithium fluoride

    NASA Astrophysics Data System (ADS)

    Nam, Eunkyoung; Oh, Seungsik; Jung, Donggeun; Kim, Hyoungsub; Chae, Heeyeop; Yi, Junsin

    2012-10-01

    In this study, we fabricated and characterized an organic photovoltaic (OPV) device with a pyromellitic dianhydride (PMDA)/lithium fluoride (LiF) cathode interfacial layer between poly(3-hexylthiophene-2,5-diyl)(P3HT)+[6,6]-phenyl C61 butyric acid methyl ester (PCBM) and Al. Compared to the OPV device with a LiF-only cathode interfacial layer having a power conversion efficiency (PCE) of 2.7%, the OPV device with the bilayer cathode interfacial structure [PMDA (0.3 nm)/LiF (0.7 nm)] exhibited a reduced resistance and a PCE value enhanced to 3.9% under an illumination condition of 100 mW cm-2 (AM1.5). The observed improvement of the OPV characteristics was attributed to the reduced leakage current of the device by the bilayer cathode interfacial layer.

  4. Effect of Copper Oxide, Titanium Dioxide, and Lithium Fluoride on the Thermal Behavior and Decomposition Kinetics of Ammonium Nitrate

    NASA Astrophysics Data System (ADS)

    Vargeese, Anuj A.; Mija, S. J.; Muralidharan, Krishnamurthi

    2014-07-01

    Ammonium nitrate (AN) is crystallized along with copper oxide, titanium dioxide, and lithium fluoride. Thermal kinetic constants for the decomposition reaction of the samples were calculated by model-free (Friedman's differential and Vyzovkins nonlinear integral) and model-fitting (Coats-Redfern) methods. To determine the decomposition mechanisms, 12 solid-state mechanisms were tested using the Coats-Redfern method. The results of the Coats-Redfern method show that the decomposition mechanism for all samples is the contracting cylinder mechanism. The phase behavior of the obtained samples was evaluated by differential scanning calorimetry (DSC), and structural properties were determined by X-ray powder diffraction (XRPD). The results indicate that copper oxide modifies the phase transition behavior and can catalyze AN decomposition, whereas LiF inhibits AN decomposition, and TiO2 shows no influence on the rate of decomposition. Possible explanations for these results are discussed. Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Energetic Materials to view the free supplemental file.

  5. Crystal structures of a double-barrelled fluoride ion channel

    PubMed Central

    Stockbridge, Randy B.; Kolmakova-Partensky, Ludmila; Shane, Tania; Koide, Akiko; Koide, Shohei; Miller, Christopher; Newstead, Simon

    2016-01-01

    To contend with hazards posed by environmental fluoride, microorganisms export this anion through F--specific ion channels of the Fluc family1–4. Since the recent discovery of Fluc channels, numerous idiosyncratic features of these proteins have been unearthed, including extreme selectivity for F- over Cl- and dual-topology dimeric assembly5–6. To understand the chemical basis for F- permeation and how the antiparallel subunits convene to form a F--selective pore, we solved crystal structures of two bacterial Fluc homologues in complex with three different monobody inhibitors, with and without F- present, to a maximum resolution of 2.1 Å. The structures reveal a surprising “double-barrelled” channel architecture in which two F- ion pathways span the membrane and the dual-topology arrangement includes a centrally coordinated cation, most likely Na+. F- selectivity is proposed to arise from the very narrow pores and an unusual anion coordination that exploits the quadrupolar edges of conserved phenylalanine rings. PMID:26344196

  6. Note: Accuracy of velocity correction for impact of a laser-accelerated miniature flyer with lithium fluoride shock-compressed along the [100] axis

    SciTech Connect

    Wakabayashi, Kunihiko; Matsumura, Tomoharu; Nakayama, Yoshio; Koshi, Mitsuo

    2011-02-15

    We performed miniature flyer impact experiments to investigate the relationship between the apparent (u{sub a}) and actual (u{sub A}) particle velocities measured by a velocity interferometer in single-crystal lithium fluoride (LiF) that was shock-compressed along the [100] axis. The miniature flyer was accelerated to velocities in the range 652.5-1937.6 m/s by a tabletop pulsed laser. An empirical relationship of u{sub a}= (1.2749 {+-} 0.0102)u{sub A} was obtained. The obtained relationship agreed well with the results of a previous study within the experimental errors and its uncertainty was less than {+-}1%. This result indicates that the present experimental technique is effective for measuring the relationship between u{sub a} and u{sub A} of shocked transparent materials with a comparable accuracy to conventional methods.

  7. Lithium-fluoride flashover ion source cleaned with a glow discharge and irradiated with vacuum-ultraviolet radiation

    SciTech Connect

    Burns, E.J.T.; Woodworth, J.R.; Bieg, K.W.; Mehlhorn, T.A.; Stygar, W.A.; Sweeney, M.A.

    1988-01-01

    We have studied methods of varying the ion species generated by a lithium-fluoride overcoated anode in a 0.5-MV magnetically insulated ion diode. We found that cleaning the anode surface with a 13.6-MHz rf glow discharge or illuminating the anode with a pulsed soft x-ray, vacuum-ultraviolet (XUV) radiation source just before the accelerator pulse significantly altered the ion species of the ion beam produced by the diode. The glow-discharge plasma removed adsorbates (carbon, hydrogen, and oxygen) from the surface of the LiF flashover source. The ions seen were lithium and hydrogen. Unfortunately, the diode impedance with a lithium-fluoride anode was high and the ion efficiency was low; however, XUV irradiation of the surface dramatically lowered the impedance by desorbing neutrals from the ion source via photon-stimulated desorption. Current densities of ten times the Child--Langmuir space-charge limit were achieved under XUV irradiation. In particular, ion currents increased by over a factor of 3 when 12 mJ/cm/sup 2/ of XUV radiation was used. However, with XUV irradiation the largest fraction of ions were fluorine, oxygen, carbon, and hydrogen, not lithium.

  8. Precise, reproducible nano-domain engineering in lithium niobate crystals

    SciTech Connect

    Boes, Andreas Sivan, Vijay; Ren, Guanghui; Yudistira, Didit; Mitchell, Arnan; Mailis, Sakellaris; Soergel, Elisabeth

    2015-07-13

    We present a technique for domain engineering the surface of lithium niobate crystals with features as small as 100 nm. A film of chromium (Cr) is deposited on the lithium niobate surface and patterned using electron beam lithography and lift-off and then irradiated with a wide diameter beam of intense visible laser light. The regions patterned with chromium are domain inverted while the uncoated regions are not affected by the irradiation. With the ability to realize nanoscale surface domains, this technique could offer an avenue for fabrication of nano-photonic and phononic devices.

  9. Lithium niobate single-crystal and photo-functional device

    DOEpatents

    Gopalan, Venkatraman; Mitchell, Terrence E.; Kitamura, Kenji; Furukawa, Yasunori

    2001-01-01

    Provided are lithium niobate single-crystal that requires a low voltage of not larger than 10 kV/nm for its ferroelectric polarization inversion and of which the polarization can be periodically inverted with accuracy even at such a low voltage, and a photo-functional device comprising the crystal. The crystal has a molar fraction of Li.sub.2 O/(Nb.sub.2 O.sub.5 +Li.sub.2 O) of falling between 0.49 and 0.52. The photo-functional device can convert a laser ray being incident thereon.

  10. Polyelectrolyte effects on the crystallization phenomena of the lithium carbonate

    NASA Astrophysics Data System (ADS)

    Watamura, Hiroto; Marukawa, Hironobu; Hirasawa, Izumi

    2013-06-01

    Anionic polyelectrolyte effects on the lithium carbonate crystallization phenomena were investigated. Li2CO3 crystals were obtained by reactive crystallization with seed crystals. Polyelectrolytes were dissolved into the reactive field before the reaction. Obtained crystals were observed with scanning electron microscopy (SEM) and crystal size and agglomeration degree were measured by the SEM images. The results show that Li2CO3 crystallized different shape and size from absence of polyelectrolyte in those reactive fields. Especially polyacrylic acid (PAA) improved on the agglomeration of the crystals and shaped them high aspect needles. Thus other experimental conditions including PAA molecular weight and concentration, reaction time, supersaturation by Li concentration were investigated in addition. As a result, obtained crystals were not different in each PAA molecular weight reactive fields. Meanwhile PAA concentration has optimum range. Li2CO3 formed less agglomeration and higher aspect around 1 g/l. In the concentration, Li2CO3 did not agglomerate regardless of aging time and Li concentration. Moreover crystals became rectangle shape in higher Li concentration.(020) face intensity of the rectangle shape crystals increased according to XRD pattern. PAA affected the facial growth. These results may provide a method of morphological change and clearly crystallization of Li2CO3.

  11. Electrospun montmorillonite modified poly(vinylidene fluoride) nanocomposite separators for lithium-ion batteries

    SciTech Connect

    Fang, Changjiang; Yang, Shuli; Zhao, Xinfei; Du, Pingfan; Xiong, Jie

    2016-07-15

    Highlights: • Composite separators of PVDF and MMT for lithium-ion batteries were electrospun. • Thermal dimensional stability and tensile property of composite separators get improved. • Presence of montmorillonite promotes electrical properties of PVDF fibrous separators. • Batteries consisting of PVDF/MMT-5% separator achieve the best performance. - Abstract: Composite separators of poly(vinylidene fluoride) (PVDF) with different contents of montmorillonite (MMT) for Li-ion batteries have been fabricated by electrospinning. The morphology, function group, crystallinity, and mechanical properties of membranes were investigated by scanning electron microscope (SEM), Fourier Transform infrared spectra (FT-IR), differential scanning calorimetry (DSC), and tensile test, respectively. Interlayer spacing of MMT in polymer was characterized by X-ray diffraction (XRD). In addition, the results of electrochemical measurements suggest that PVDF/MMT-5% composite membrane has maximum ionic conductivity of 4.2 mS cm{sup −1}, minimum interfacial resistance of 97 Ω, and excellent electrochemical stability. The cell comprising PVDF/MMT-5% composite membrane shows higher capacity and more stable cycle performance than the one using commercial Celgard PP membrane.

  12. Crystal Structures of Diaryliodonium Fluorides and their Implications for Fluorination Mechanisms.

    PubMed

    Lee, Yong Sok; Chun, Joong-Hyun; Hodošček, Milan; Pike, Victor

    2017-01-31

    The radiofluorination of diaryliodonium salts is of value for producing radiotracers for positron emission tomography. We report crystal structures for two diaryliodonium fluorides. Whereas diphenyliodon um fluoride (1a) exists as a tetramer bridged by four fluoride ions, 2-methylphenyl(phenyl)iodonium fluoride (2a) forms a fluoride-bridged dimer that is further halogen-bonded to two other monomers. We discuss the topological relationships between the two and their implications for fluorination in solution. Both radiofluorination and NMR spectroscopy show that thermolysis of 2a gives 2-fluorotoluene and fluorobenzene in a 2 to 1 ratio that is in good agreement with the ratio observed from the radiofluorination of 2-methylphenyl(phenyl)iodonium chloride (2b). The constancy of the product ratio affirms that the fluorinations occur via the same two rapidly interconverting transition states whose energy difference dictates chemoselectivity. The quantum chemical studies with density functional theory at the level of B3LYP/DGDZVP provide deeper insight into the role of 'ortho effect' in the mechanism of fluorination. By utilizing the crystal structures of 1a and 2a, the mechanisms of fluoroarene formation from diaryliodonium fluorides in their monomeric, homodimeric, heterodimeric, and tetrameric states were also investigated. According to this analysis, we propose that oligomerization energy dictates whether the fluorination occurs through a monomeric or an oligomeric pathway.

  13. A EPR Investigation of Atomic Silver and Divalent Silver in Irradiated Single Crystal of Potassium Fluoride Doped with Silver Fluoride

    NASA Astrophysics Data System (ADS)

    Yu, Cheng

    The electron paramagnetic resonance absorption spectra of a singly ionized diatomic fluoride molecule -ion F_2^-, atomic silver Ag^0 and divalent silver Ag ^{2+} contained in single crystals of potassium fluoride have been re-examined at X-band wavelengths. The F_2^- and Ag^0 centers are produced simultaneously by gamma-irradiation at liquid nitrogen temperature. The divalent silver Ag^{2+} centers are formed by subsequently warming the irradiated samples to room temperature for a few hours and then cooling to 77 K. All field strength positions of resonance absorption lines observed at low temperatures have been satisfactorily predicted by computer simulation. The high degree of resolution exhibited by the spectra is due in part to the large nuclear magnetic moment of fluorine and in part to the fact that spectral lines in KF are narrow compared to those of similar systems in other alkali halide crystals. For an atomic silver, the hexafluoride cluster is cubic. By contrast, the divalent silver center is tetragonally distorted along a crystal cube edge as a consequence of the Jahn-Teller effect. Unexpected splittings of the central lines in the resonance absorption spectrum of divalent silver are observed and interpreted as being due to second order perturbation effects.

  14. Origin of electronic transport of lithium phthalocyanine iodine crystal

    SciTech Connect

    Koike, Noritake; Oda, Masato; Shinozuka, Yuzo

    2013-12-04

    The electronic structures of Lithium Phthalocyanine Iodine are investigated using density functional theory. Comparing the band structures of several model crystals, the metallic conductivity of highly doped LiPcI{sub x} can be explained by the band of doped iodine. These results reveal that there is a new mechanism for electronic transport of doped organic semiconductors that the dopant band plays the main role.

  15. Origins of Large Voltage Hysteresis in High-Energy-Density Metal Fluoride Lithium-Ion Battery Conversion Electrodes.

    PubMed

    Li, Linsen; Jacobs, Ryan; Gao, Peng; Gan, Liyang; Wang, Feng; Morgan, Dane; Jin, Song

    2016-03-02

    Metal fluorides and oxides can store multiple lithium ions through conversion chemistry to enable high-energy-density lithium-ion batteries. However, their practical applications have been hindered by an unusually large voltage hysteresis between charge and discharge voltage profiles and the consequent low-energy efficiency (<80%). The physical origins of such hysteresis are rarely studied and poorly understood. Here we employ in situ X-ray absorption spectroscopy, transmission electron microscopy, density functional theory calculations, and galvanostatic intermittent titration technique to first correlate the voltage profile of iron fluoride (FeF3), a representative conversion electrode material, with evolution and spatial distribution of intermediate phases in the electrode. The results reveal that, contrary to conventional belief, the phase evolution in the electrode is symmetrical during discharge and charge. However, the spatial evolution of the electrochemically active phases, which is controlled by reaction kinetics, is different. We further propose that the voltage hysteresis in the FeF3 electrode is kinetic in nature. It is the result of ohmic voltage drop, reaction overpotential, and different spatial distributions of electrochemically active phases (i.e., compositional inhomogeneity). Therefore, the large hysteresis can be expected to be mitigated by rational design and optimization of material microstructure and electrode architecture to improve the energy efficiency of lithium-ion batteries based on conversion chemistry.

  16. Fluoride incorporation into apatite crystals delays amelogenin hydrolysis

    PubMed Central

    DenBesten, Pamela; Zhu, Li; Li, Wu; Tanimoto, Kotaro; Liu, Haichuan; Witkowska, Halina Ewa

    2012-01-01

    Enamel fluorosis has been related to an increase in the amount of amelogenin in fluorosed enamel as compared to normal enamel in the maturation stage. In this study we tested the hypothesis that fluoride incorporated into carbonated apatite alters amelogenin hydrolysis. Recombinant human amelogenin (rh174) was allowed to bind to 0.15 mg of carbonated hydroxyapatite (CAP) or fluoride-containing carbonated hydroxyapatite (F-CAP) synthesized to contain 100, 1000 or 4000 ppm F-. After 3 h digestion with recombinant human MMP20 or KLK4, bound protein was characterized by reverse-phase HPLC. Proteolytic fragments formed after 24 h digestion of amelogenin, were identified by LC tandem mass spectrometry (LCMS/MS). The hydrolysis of amelogenin bound to F100-CAP by both MMP20 and KLK4 was significantly reduced in a dose dependent manner as compared to CAP. After 24 h hydrolysis, the number of cleavage sites in bound amelogenin by MMP20 were similar in CAP and F100-CAP, whereas there were 24 fewer cleavage sites identified for the KLK4 hydrolysis on F100-CAP as compared to CAP. These results suggest that the reduced hydrolysis of amelogenins in fluorosed enamel may be partially due to the increased fluoride content in fluoride containing apatite, contributing to the hypomineralized enamel matrix phenotype observed in fluorosed enamel. PMID:22243219

  17. Divalent fluoride doped cerium fluoride scintillator

    DOEpatents

    Anderson, David F.; Sparrow, Robert W.

    1991-01-01

    The use of divalent fluoride dopants in scintillator materials comprising cerium fluoride is disclosed. The preferred divalent fluoride dopants are calcium fluoride, strontium fluoride, and barium fluoride. The preferred amount of divalent fluoride dopant is less than about two percent by weight of the total scintillator. Cerium fluoride scintillator crystals grown with the addition of a divalent fluoride have exhibited better transmissions and higher light outputs than crystals grown without the addition of such dopants. These scintillators are useful in radiation detection and monitoring applications, and are particularly well suited for high-rate applications such as positron emission tomography (PET).

  18. Fluoride incorporation into apatite crystals delays amelogenin hydrolysis.

    PubMed

    DenBesten, Pamela K; Zhu, Li; Li, Wu; Tanimoto, Kotaro; Liu, Haichuan; Witkowska, Halina E

    2011-12-01

    Enamel fluorosis has been related to an increase in the amount of amelogenin in fluorosed enamel compared with normal enamel in the maturation stage. In this study we tested the hypothesis that fluoride incorporated into carbonated apatite alters amelogenin hydrolysis. Recombinant human amelogenin (rh174) was allowed to bind to 0.15 mg of carbonated hydroxyapatite (CAP) or to fluoride-containing carbonated hydroxyapatite (F-CAP) synthesized to contain 100, 1,000, or 4,000 ppm F(-). After 3 h of digestion with recombinant human matrix metalloproteinase 20 (MMP20) or kallikrein-related peptidase 4 (KLK4), bound protein was characterized by reverse-phase high-performance liquid chromatography (HPLC). Proteolytic fragments of amelogenin formed after 24h of digestion with MMP20 of KLK 4 were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The hydrolysis, by both MMP20 and KLK4, of amelogenin bound to F100-CAP was significantly reduced in a dose-dependent manner compared with the hydrolysis of amelogenin bound to CAP. After 24 h of hydrolysis, a similar number of MMP20 cleavage sites was found for amelogenin bound to CAP and amelogenin bound to F100-CAP; however, 24 fewer KLK4 cleavage sites were identified for amelogenin bound to F100-CAP than for amelogenin bound to CAP. These results suggest that the reduced hydrolysis of amelogenins in fluorosed enamel may be partially caused by the increased fluoride content in fluoride-containing apatite, contributing to the hypomineralized enamel matrix phenotype observed in fluorosed enamel.

  19. Effect of chloride incorporation on the crystallization of zirconium-barium-lanthanum-aluminum fluoride glass

    NASA Technical Reports Server (NTRS)

    Neilson, G. F.; Smith, G. L.; Weinberg, M. C.

    1985-01-01

    One aspect of the influence of preparation procedure on the crystallization behavior of a zirconium-barium-lanthanum-aluminum fluoride glass was studied. The crystallization pattern of this glass may be affected by the chlorine concentration within it. In particular, when such glasses are heated at low temperatures, the alpha-Ba-Zr-F6 crystalline phase forms only in those glasses which contain chloride.

  20. Liquid crystal deposition on poled, single crystalline lithium niobate

    NASA Astrophysics Data System (ADS)

    Bharath, S. C.; Pimputkar, K. R.; Pronschinske, A. M.; Pearl, T. P.

    2008-01-01

    For the purpose of elucidating the mechanisms for molecular organization at poled ferroelectric surfaces, single crystalline lithium niobate (LN), 'Z-cut' along the (0 0 0 1) plane, has been prepared and characterized and subsequently exposed to liquid crystal molecules. As a model system we chose to study the anchoring of 4- n-octyl-4'-cyanobiphenyl (8CB) to LN. Liquid crystalline films are of interest because of their useful electronic and optical properties as well as chemical sensing attributes. Low-energy electron diffraction (LEED), atomic force microscopy (AFM), surface contact angle measurements (CA), and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface of lithium niobate as well as the nature of 8CB films grown on the surface. Atomically flat LN surfaces were prepared as a support for monolayer thick, 8CB molecular domains. 8CB liquid crystal molecules were deposited by an ambient vaporization technique and the films were analyzed using XPS and CA. Understanding electrostatic anchoring mechanisms and thin film organization for this molecule on uniformly poled surfaces allows for a fuller appreciation of how molecular deposition of other polarizable molecules on periodically poled and patterned poled lithium niobate surfaces would occur.

  1. Structural changes of conversion metal fluoride cathodes in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Sina, Mahsa

    Currently, cathode materials for Li-ion batteries are based on intercalation processes where, during charge and discharge processes, Li intercalates into the crystal lattice while maintaining the host crystal structure. More recently, new cathode materials have been introduced based on conversion reactions involving phase transformation and complete reduction of the host transition metal. In addition, conversion reactions involve two or more Li ions with a resulting much higher capacity than obtainable for intercalation materials. However, mechanism of phase transformation and cycling reversibility are at present still poorly understood. In this study transmission electron microscopy (TEM) techniques including selected area electron diffraction (SAED) pattern, annular dark field (ADF) STEM image, and electron energy loss spectroscopy (EELS) with nanoscale spatial resolution were used to study the phase evolution and structural changes of iron fluorides (FeFe2, FeO0.7F 1.3, FeF3) after various discharge/charge cycles. Additionally, the changes of the Fe valence states upon cycling were determined using EELS by measuring the L3/L2 intensity ratio of Fe-L edge. The structural transformations of FeO0.7F1.3 during the first lithiation show that litiahation contains two regions. The first region, lithiation is an intercalation reaction with reduction of Fe 3+ to Fe2+. The second region of lithiation involves a conversion reaction, with the formation of metallic Fe, LiF, and Li 0.7Fe2+0.5O0.7F0.3 (rocksalt type) phases. The first delithiation process follows a different conversion reaction path compared to the first lithiation reaction involving the formation an amorphous rutile-type phase along with with the rocksalt-type phase. Interestingly, upon full recharge (delithiated electrode), the measured average Fe valence state returns back to its initial value of Fe2.7+. The growth of a solid electrolyte interphase (SEI) layer formation at the electrode

  2. Capillary electrophoresis with contactless conductivity detection for the quantification of fluoride in lithium ion battery electrolytes and in ionic liquids-A comparison to the results gained with a fluoride ion-selective electrode.

    PubMed

    Pyschik, Marcelina; Klein-Hitpaß, Marcel; Girod, Sabrina; Winter, Martin; Nowak, Sascha

    2017-02-01

    In this study, an optimized method using capillary electrophoresis (CE) with a direct contactless conductivity detector (C(4) D) for a new application field is presented for the quantification of fluoride in common used lithium ion battery (LIB) electrolyte using LiPF6 in organic carbonate solvents and in ionic liquids (ILs) after contacted to Li metal. The method development for finding the right buffer and the suitable CE conditions for the quantification of fluoride was investigated. The results of the concentration of fluoride in different LIB electrolyte samples were compared to the results from the ion-selective electrode (ISE). The relative standard deviations (RSDs) and recovery rates for fluoride were obtained with a very high accuracy in both methods. The results of the fluoride concentration in the LIB electrolytes were in very good agreement for both methods. In addition, the limit of detection (LOD) and limit of quantification (LOQ) values were determined for the CE method. The CE method has been applied also for the quantification of fluoride in ILs. In the fresh IL sample, the concentration of fluoride was under the LOD. Another sample of the IL mixed with Li metal has been investigated as well. It was possible to quantify the fluoride concentration in this sample.

  3. Spectroscopy and Excitation Dynamics of the Trivalent Lanthanides THULIUM(3+) and HOLMIUM(3+) in Yttrium Lithium Fluoride.

    NASA Astrophysics Data System (ADS)

    Walsh, Brian Michael

    A detailed study of the spectroscopy and excitation dynamics of the trivalent lanthanides Tm^ {3+} and Ho^{3+} in Yttrium Lithium Fluoride, LiYF_4 (YLF), has been done. YLF is a very versatile laser host that has been used to produce laser action at many different wavelengths when doped with trivalent lanthanides. Since the early 1970's YLF has been the subject of many studies, the main goal of which has been to produce long wavelength lasers in the eye safe 2mum region. This study concentrates on a presentation and analysis of the spectroscopic features, and the temporal evolution of excitation energy in YLF crystals doped with Tm^{3+ } and Ho^{3+} ions. Absorption spectroscopy is studied to identify wavelength regions where energy can be absorbed in Holmium YLF and Thulium YLF, and to determine their respective absorption cross sections. These measurements are applied in the Judd-Ofelt theory to determine radiative transition rates of spontaneous emission. Luminescence spectroscopy is studied under cw diode laser excitation at 785nm. The effect of dopant ion concentration and excitation power on the observed luminescence are considered in these measurements. An analysis of these measurements have been used to determine channels of energy transfer between Tm^ {3+} and Ho^{3+} ions (cross relaxation, upconversion, and resonant energy transfer). The temporal response of Tm and Ho in singly and co-doped YLF to pulsed laser excitation with a Ti:Al_2O_3 laser and a CoMgF_2 laser tuned to various wavelengths have also been studied. The energy transfer mechanisms of cross relaxation, upconversion, and resonant energy transfer between Tm^ {3+} and Ho^{3+} ions have been modeled, and the model parameters extracted by a fitting procedure to the measured temporal response curves. Rate equation approaches to modeling are presented that result in predictions of rate constants for energy transfer processes, as well as more conventional approaches to modeling such as the Forster

  4. Ammonium Fluoride Mediated Synthesis of Anhydrous Metal Fluoride-Mesoporous Carbon Nanocomposites for High-Performance Lithium Ion Battery Cathodes.

    PubMed

    Chun, Jinyoung; Jo, Changshin; Sahgong, Sunhye; Kim, Min Gyu; Lim, Eunho; Kim, Dong Hyeon; Hwang, Jongkook; Kang, Eunae; Ryu, Keun Ah; Jung, Yoon Seok; Kim, Youngsik; Lee, Jinwoo

    2016-12-28

    Metal fluorides (MFx) are one of the most attractive cathode candidates for Li ion batteries (LIBs) due to their high conversion potentials with large capacities. However, only a limited number of synthetic methods, generally involving highly toxic or inaccessible reagents, currently exist, which has made it difficult to produce well-designed nanostructures suitable for cathodes; consequently, harnessing their potential cathodic properties has been a challenge. Herein, we report a new bottom-up synthetic method utilizing ammonium fluoride (NH4F) for the preparation of anhydrous MFx (CuF2, FeF3, and CoF2)/mesoporous carbon (MSU-F-C) nanocomposites, whereby a series of metal precursor nanoparticles preconfined in mesoporous carbon were readily converted to anhydrous MFx through simple heat treatment with NH4F under solventless conditions. We demonstrate the versatility, lower toxicity, and efficiency of this synthetic method and, using XRD analysis, propose a mechanism for the reaction. All MFx/MSU-F-C prepared in this study exhibited superior electrochemical performances, through conversion reactions, as the cathode for LIBs. In particular, FeF3/MSU-F-C maintained a capacity of 650 mAh g(-1)FeF3 across 50 cycles, which is ∼90% of its initial capacity. We expect that this facile synthesis method will trigger further research into the development of various nanostructured MFx for use in energy storage and other applications.

  5. N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide-electrospun polyvinylidene fluoride composite electrolytes: characterization and lithium cell studies.

    PubMed

    Zhou, Yundong; Wang, Xiaoen; Zhu, Haijin; Armand, Michel; Forsyth, Maria; Greene, George W; Pringle, Jennifer M; Howlett, Patrick C

    2017-01-18

    Using the organic ionic plastic crystal N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C2mpyr][FSI]) with electrospun nanofibers, LiFSI doped [C2mpyr][FSI]-PVdF composites were developed as solid state, self-standing electrolyte membranes. Different lithium salt concentration were investigated, with 10 mol% LiFSI found to be optimal amongst those assessed. Composites with different weight ratios of plastic crystal and polymer were prepared and 10 wt% polymer gave the highest conductivity. In addition, the effects of PVdF incorporation on the morphological, thermal, and structural properties of the organic ionic plastic crystal were investigated. Ion mobilities were also studied using solid-state nuclear magnetic resonance techniques. The electrolytes were then assembled into lithium symmetric cells and cycled galvanostatically at 0.13 mA cm(-2) at both ambient temperature and at 50 °C, for more than 500 cycles.

  6. Effect of fluoride on the morphology of calcium phosphate crystals grown on acid-etched human enamel.

    PubMed

    Fan, Y; Sun, Z; Moradian-Oldak, J

    2009-01-01

    The aim of this study was to examine the effect of fluoride ion concentration on the morphology of calcium phosphate crystals grown on acid-etched enamel as a model for tooth enamel erosion. Samples were immersed in calcification solution for 16 h and changes in crystal morphology were monitored by field emission scanning electron microscopy. Without fluoride, plate-like octacalcium phosphate crystals (20 nm thick, 2-10 microm wide) were formed. With 1-10 mg/l fluoride, arrays of denser needle-like nanocrystals (20-30 nm wide, >500 nm in length) were formed. We conclude that there is a minimal fluoride concentration (1 mg/l) that dramatically affects the morphology of calcium phosphate crystals grown on etched enamel in vitro.

  7. Effect of Fluoride on the Morphology of Calcium Phosphate Crystals Grown on Acid-Etched Human Enamel

    PubMed Central

    Fan, Y.; Sun, Z.; Moradian-Oldak, J.

    2009-01-01

    The aim of this study was to examine the effect of fluoride ion concentration on the morphology of calcium phosphate crystals grown on acid-etched enamel as a model for tooth enamel erosion. Samples were immersed in calcification solution for 16 h and changes in crystal morphology were monitored by field emission scanning electron microscopy. Without fluoride, plate-like octacalcium phosphate crystals (20 nm thick, 2–10 μm wide) were formed. With 1–10 mg/l fluoride, arrays of denser needle-like nanocrystals (20–30 nm wide, >500 nm in length) were formed. We conclude that there is a minimal fluoride concentration (1 mg/l) that dramatically affects the morphology of calcium phosphate crystals grown on etched enamel in vitro. PMID:19321991

  8. Conductivity degradation of polyvinylidene fluoride composite binder during cycling: Measurements and simulations for lithium-ion batteries

    SciTech Connect

    Grillet, Anne M.; Humplik, Thomas; Stirrup, Emily K.; Roberts, Scott A.; Barringer, David A.; Snyder, Chelsea M.; Janvrin, Madison R.; Apblett, Christopher A.

    2016-07-02

    The polymer-composite binder used in lithium-ion battery electrodes must both hold the electrodes together and augment their electrical conductivity while subjected to mechanical stresses caused by active material volume changes due to lithiation and delithiation. We have discovered that cyclic mechanical stresses cause significant degradation in the binder electrical conductivity. After just 160 mechanical cycles, the conductivity of polyvinylidene fluoride (PVDF):carbon black binder dropped between 45–75%. This degradation in binder conductivity has been shown to be quite general, occurring over a range of carbon black concentrations, with and without absorbed electrolyte solvent and for different polymer manufacturers. Mechanical cycling of lithium cobalt oxide (LiCoO2) cathodes caused a similar degradation, reducing the effective electrical conductivity by 30–40%. Mesoscale simulations on a reconstructed experimental cathode geometry predicted the binder conductivity degradation will have a proportional impact on cathode electrical conductivity, in qualitative agreement with the experimental measurements. Lastly, ohmic resistance measurements were made on complete batteries. Direct comparisons between electrochemical cycling and mechanical cycling show consistent trends in the conductivity decline. This evidence supports a new mechanism for performance decline of rechargeable lithium-ion batteries during operation – electrochemically-induced mechanical stresses that degrade binder conductivity, increasing the internal resistance of the battery with cycling.

  9. Conductivity degradation of polyvinylidene fluoride composite binder during cycling: Measurements and simulations for lithium-ion batteries

    DOE PAGES

    Grillet, Anne M.; Humplik, Thomas; Stirrup, Emily K.; ...

    2016-07-02

    The polymer-composite binder used in lithium-ion battery electrodes must both hold the electrodes together and augment their electrical conductivity while subjected to mechanical stresses caused by active material volume changes due to lithiation and delithiation. We have discovered that cyclic mechanical stresses cause significant degradation in the binder electrical conductivity. After just 160 mechanical cycles, the conductivity of polyvinylidene fluoride (PVDF):carbon black binder dropped between 45–75%. This degradation in binder conductivity has been shown to be quite general, occurring over a range of carbon black concentrations, with and without absorbed electrolyte solvent and for different polymer manufacturers. Mechanical cycling ofmore » lithium cobalt oxide (LiCoO2) cathodes caused a similar degradation, reducing the effective electrical conductivity by 30–40%. Mesoscale simulations on a reconstructed experimental cathode geometry predicted the binder conductivity degradation will have a proportional impact on cathode electrical conductivity, in qualitative agreement with the experimental measurements. Lastly, ohmic resistance measurements were made on complete batteries. Direct comparisons between electrochemical cycling and mechanical cycling show consistent trends in the conductivity decline. This evidence supports a new mechanism for performance decline of rechargeable lithium-ion batteries during operation – electrochemically-induced mechanical stresses that degrade binder conductivity, increasing the internal resistance of the battery with cycling.« less

  10. Generation of ionizing radiation from lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Orlikov, L. N.; Orlikov, N. L.; Arestov, S. I.; Mambetova, K. M.; Shandarov, S. M.

    2017-01-01

    The work done experimentally explores generation of electron and x-ray radiation in the process of heating and cooling monolithic and iron-doped crystals of lithium niobate. Iron doping to the concentrations in the range of 1023 m3 was carried out by adding ferric oxide into the melt during the process of crystal growth. The research into radiation generation was performed at 1-10 Pa. The speed of heating from -10 to 1070 C was 10-20 degrees a minute. Current pulses appeared at 17, 38, 56, 94, 98, 100, 105, 106, 1070 C with the interval of 1-3 minutes. The obtained electron current increased in direct proportion to the crystal surface area. The maximum current was 3mA at the design voltage 11 kV on the crystal with 14,5x10,5x10 mm3 surface area. The article describes the possibility to control the start of generation by introducing priming pulse. The results achieved are explained by the domain repolarization while heating the crystal and the appearance of electric field local strength. Bias and overcharge currents contribute to the appearance of electric strength, which stimulates breakdown and plasma formation. X-ray radiation appears both at the stage of discharge formation and during electron deceleration on gas and target material.

  11. Growth of lithium triborate crystals. II. Experimental results

    NASA Astrophysics Data System (ADS)

    Parfeniuk, C.; Samarasekera, I. V.; Weinberg, F.; Edel, J.; Fjeldsted, K.; Lent, B.

    1996-02-01

    In Part I [C. Parfeniuk, I.V. Samarasekera and F. Weinberg, J. Crystal Growth 158 (1996) 514], a mathematical model of the flux growth of lithium triborate (LBO) crystals was used to calculate the temperature distribution and fluid flow in the melt during growth. In this report the model results are related to experimental observations. Temperature measurements in the melt, for different crucible rotation rates, are compared to the corresponding temperatures determined from the model. Direct observations of fluid flow in the melt, using a transparent glycerol/water solution as a physical model, are related to the calculated flow paths and velocities. As the LBO crystal grows, the rejected MoO 3 flux concentrates ahead of the interface leading to the formation of eutectic phases. The factors leading to the formation of these phases are examined, using flow velocity values determined from the model. A number of LBO crystals were grown, first using convenient growth parameters, and then using parameters determined from the model results. The size and quality of the crystals obtained are discussed and related to the growth conditions.

  12. Crystallization of lithium disilicate glass using variable frequency microwave processing

    NASA Astrophysics Data System (ADS)

    Mahmoud, Morsi Mohamed

    The lithium disilicate (LS2) glass system provides the basis for a large number of useful glass-ceramic products. Microwave processing of materials such as glass-ceramics offers unique benefits over conventional processing techniques. Variable frequency microwave (VFM) processing is an advanced processing technique developed to overcome the hot spot and the arcing problems in microwave processing. In general, two main questions are addressed in this dissertation: (1) How does microwave energy couple with a ceramic material to create heat? and, (2) Is there a "microwave effect" and if so what are the possible explanations for the existence of that effect? The results of the present study show that VFM processing was successfully used to crystallize LS2 glass at a frequency other than 2.45 GHz and without the aid of other forms of energy (hybrid heating). Crystallization of LS2 glass using VFM heating occurred in a significantly shorter time and at a lower temperature as compared to conventional heating. Furthermore, the crystallization mechanism of LS2 glass in VFM heating was not exactly the same as in conventional heating. Although LS2 crystal phase (Orthorhombic Ccc2) was developed in the VFM crystallized samples as well as in the conventionally crystallized samples as x-ray diffraction (XRD) confirmed, the structural units of SiO4 tetrahedra (Q species) in the VFM crystallized samples were slightly different than the ones in conventionally crystallized samples as the Raman spectroscopy revealed. Moreover, the observed reduction in the crystallization time and apparent temperature in addition to the different crystallization mechanism observed in the VFM process both provided experimental evidence to support the presence of the microwave effect in the LS2 crystallization process. Also, the molecular orbital model was successfully used to predict the microwave absorption in LS2 glass and glass-ceramic. This model was consistent with experiments and indicated that

  13. Neutron beam test of barium fluoride crystal for dark matter direct detection

    NASA Astrophysics Data System (ADS)

    Guo, C.; Ma, X. H.; Wang, Z. M.; Bao, J.; Dai, C. J.; Guan, M. Y.; Liu, J. C.; Li, Z. H.; Ren, J.; Ruan, X. C.; Yang, C. G.; Yu, Z. Y.; Zhong, W. L.

    2016-10-01

    In order to test the capabilities of Barium Fluoride (BaF2) crystal for dark matter direct detection, nuclear recoils are studied with mono-energetic neutron beam. The energy spectra of nuclear recoils, quenching factors for elastic scattering neutrons and discrimination capability between neutron inelastic scattering events and γ events are obtained for various recoil energies of the F content in BaF2.

  14. Mode-locking optimization with a real-time feedback system in a Nd:yttrium lithium fluoride laser cavity.

    PubMed

    Marengoni, C; Canova, F; Batani, D; Benocci, R; Librizzi, M; Narayanan, V; Gomareschi, M; Lucchini, G; Kilpio, A; Shashkov, E; Stuchebrukhov, I; Vovchenko, V; Chernomyrdin, V; Krasuyk, I; Hall, T; Bittanti, S

    2007-01-01

    We present a control system, which allows an automatic optimization of the pulse train stability in a mode-locked laser cavity. In order to obtain real-time corrections, we chose a closed loop approach. The control variable is the cavity length, mechanically adjusted by gear system acting on the rear cavity mirror, and the controlled variable is the envelope modulation of the mode-locked pulse train. Such automatic control system maintains the amplitude of the mode-locking pulse train stable within a few percent rms during the working time of the laser. Full implementation of the system on an Nd:yttrium lithium fluoride actively mode-locked laser is presented.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  16. Shock compression experiments on Lithium Deuteride single crystals.

    SciTech Connect

    Knudson, Marcus D.; Desjarlais, Michael Paul; Lemke, Raymond W.

    2014-10-01

    S hock compression exper iments in the few hundred GPa (multi - Mabr) regime were performed on Lithium Deuteride (LiD) single crystals . This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17 - 32 km/s. Measurements included pressure, density, and temperature between %7E200 - 600 GPa along the Principal Hugoniot - the locus of end states achievable through compression by large amplitude shock waves - as well as pressure and density of re - shock states up to %7E900 GPa . The experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  17. Electrical conduction in nanodomains in congruent lithium tantalate single crystal

    SciTech Connect

    Cho, Yasuo

    2014-01-27

    The electrical current flow behavior was investigated for nanodomains formed in a thin congruent lithium tantalate (LiTaO{sub 3}) single-crystal plate. When the nanodomains were relatively large, with diameters of about 100 nm, current flow was detected along the domain wall. However, when they were about 40 nm or smaller, the current flowed through the entire nanodomain. Schottky-like rectifying behavior was observed. Unlike the case of LiNbO{sub 3}, optical illumination was not required for current conduction in LiTaO{sub 3}. A clear temperature dependence of the current was found indicating that the conduction mechanism for nanodomains in LiTaO{sub 3} may involve thermally activated carrier hopping.

  18. Optical properties of Eu2+ doped antipervoskite fluoride single crystals

    NASA Astrophysics Data System (ADS)

    Daniel, D. Joseph; Nithya, R.; Ramasamy, P.; Madhusoodanan, U.

    2013-02-01

    Single crystals of pure and Eu2+ doped LiBaF3 have been grown from melt by using a vertical Bridgman-Stockbarger method. Absorption and luminescence spectra for pure and rare-earth-doped LiBaF3 were studied. At ambient conditions the photoluminescence spectra consisted of sharp lines peaked at ˜359 nm attributed to the 6P7/2→8S7/2 transitions in the 4f7 electronic configuration of Eu2+ and a broad band extending between 370 and 450 nm attributed to Eu2+ trapped exciton recombination. The effect of 60Co gamma irradiation has also been investigated.

  19. Dissolution of Alkali Fluoride and Chloride Crystals in Water Studied by Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Fukushima, N.; Tamura, Y.; Ohtaki, H.

    1991-02-01

    The dissolution of cubic crystals of NaF, KF, CsF, LiCl, NaCl, and KCl consisting of 32 cations and 32 anions in an isolated box containing 216 water molecules was studied at 298 K by molecular dynamics simulations. The ion-ion, ion-water and water-water interactions were described in terms of the Tosi-Fumi, Kistenmacher-Popkie-Clementi, and Matsuoka-Clementi-Yoshimine potentials, respectively. During the simulation periods of 12 ps for NaF, CsF and LiCl and 20 ps for KF, NaCl and KCl cations did not dissolve, while anions dissolved from the CsF, LiCl and NaCl crystals but not from the NaF, KF and KCl crystals. The mass effect in the dissolution of CsF was examined by giving the ceasium ions the atomic weight of the fluoride ion (18.998). In case of the "light" caesium ions in the crystal fluctuated less far and again fluoride ions but no caesium ions were dissolved.

  20. [Study on Spectral Characteristics of Two Kinds of Home-Made Novel Yb-Doped Fluoride Laser Crystals].

    PubMed

    Xu, Wen-bin; Chai, Lu; Shi, Jun-kai; Song, You-jian; Hu, Ming-lie; Wang, Qing-yue; Su, Liang-bi; Jiang, Da-peng; Xu, Jun

    2015-09-01

    Yb-doped fluoride crystals are of important another Yb-doped laser materials besides Yb-doped oxide, which are becoming one of interests for developing tunable lasers and ultrafast lasers. In this paper, the systematic and contrastive experiments of the optical spectral characteristics are presented for two types of home-made novel Yb-doped fluoride laser crystals, namely, Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal. The fluorescent features of Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal are apparently different by the fluorescence experiment. The physical mechanism of these fluorescence spectra were analyzed and proposed. The influence of doping concentrations of active Yb(3+) ions or co-doping Y ions on the absorption of Yb-doped CaF2-SrF2 mixed crystal and co-doped Yb, Y:CaF2 single crystal was experimentally investigated, and the optimal values of doping concentrations of active Yb(3+) ions or co-doping Y ions in the two types of fluoride laser crystals were obtained. Continuous-wave laser operation for the two novel fluoride laser crystals has been achieved in three-mirror-folded resonator using a laser diode as the pump source. Therein, the laser operation for the co-doped Yb, Y:CaF2 crystal is demonstrated for the first time. For the two types of fluoride laser crystals (four samples), the input-output power relational curves, the optical slope efficiencies and the laser spectra were demonstrated by the laser experiments. By comparisons between the two types of fluoride laser crystals in the absorbability, fluorescence and laser spectra, laser threshold and slope efficiency of the continuous-wave laser operation, the results show that the best one of the four samples in spectral and laser characteristics is co-doped 3at%Yb, 6at% Y:CaF2 single crystal, which has an expected potential in the application. The research results provide available references for improving further laser performance of Yb

  1. In-Situ Crystallization of a Lithium Disilicate Glass--Effect of Pressure on Crystal Growth Rate

    NASA Technical Reports Server (NTRS)

    Fuss, T.; Ray, C. S.; Lesher, C. E.; Day, D. E.

    2006-01-01

    Crystallization of a Li2O.2SiO2 (LS2) glass subjected to a uniform hydrostatic pressure of 4.5 GPa and 6 GPa was investigated up to a temperature of 750 C. The density of the compressed glass is about 2% greater at 4.5 GPa than at 1 atm and, depending upon the processing temperature, up to 10% greater at 6 GPa. Crystal growth rates investigated as a function of temperature and pressure show that lithium disilicate crystal growth is an order of magnitude slower at 4.5 GPa than 1 atm resulting in a shift of +45 C (plus or minus 10 C) in the growth rate curve at high pressure compared to 1 atm condition. At 6 GPa lithium disilicate crystallization is suppressed entirely, while a new high pressure lithium metasilicate crystallizes at temperatures 95 C (plus or minus 10 C) higher than those reported for lithium disilicate crystallization at 1 atm. The decrease in crystal growth rate with increasing pressure for lithium disilicate glass up to 750 C is related to an increase in viscosity with pressure associated with fundamental changes in glass structure accommodating densification.

  2. On the existence of ``l-threonine formate'', ``l-alanine lithium chloride'' and ``bis l-alanine lithium chloride'' crystals

    NASA Astrophysics Data System (ADS)

    Petrosyan, A. M.; Ghazaryan, V. V.; Fleck, M.

    2013-03-01

    We argue that the recently reported crystals "L-threonine formate" as well as "L-alanine lithium chloride" and "bis L-alanine lithium chloride" actually are the well-known crystals L-threonine and L-alanine, respectively.

  3. Growth, spectral and crystallization perfection studies of semi organic non linear optical crystal - L-alanine lithium chloride

    NASA Astrophysics Data System (ADS)

    Redrothu, Hanumantharao; Kalainathan, S.; Bhagavannarayana, G.

    2012-06-01

    Single crystals of L-alanine lithium chloride single crystals were successfully grown using slow evaporation solution growth technique at constant temperature (303K). The formation of the new crystal has been confirmed by single-crystal X-ray diffraction, FT-IR studies. The crystalline perfection was analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. The powder second harmonic generation (SHG) has been confirmed by Nd: YAG laser. The results have been discussed in detail.

  4. Refinement of the crystal structure of lithium-bearing uvite

    SciTech Connect

    Rozhdestvenskaya, I. V. Frank-Kamenetskaya, O. V.; Kuznetsova, L. G.; Bannova, I. I.; Bronzova, Yu. M.

    2007-03-15

    The crystal structure of a natural calcium tourmaline, i.e., uvite with a high lithium content (0.51 au per formula (aupf) at the Y site, is refined to R = 0.019, R{sub w} = 0.020, and S = 1.11. It is shown that, in nature, there exist uvites in which the charge balance in the case where the Z site is occupied by trivalent cations is provided by the replacement of part of the divalent magnesium cations at the Y site by univalent cations, divalent calcium cations at the X site by sodium cations, and univalent anions at the W site by oxygen anions. The W site is found to be split into two sites, namely, the W1 and W11 sites (the W1-W11 distance is 0.14 A), which are partially occupied by the fluorine and oxygen anions, respectively. An analysis of the results obtained in this study and the data available in the literature on the crystal structure of uvites allows the conclusion that uvite can be considered a superspecies and that the nomenclature of this mineral group needs refinement with the use of structural data.

  5. Growth and characterization of Cu (II) doped negatively soluble lithium sulfate monohydrate crystals

    NASA Astrophysics Data System (ADS)

    Boopathi, K.; Ramasamy, P.; Bhagavannarayana, G.

    2014-01-01

    Single crystals of pure and Cu (II) doped negatively soluble lithium sulfate monohydrate have been grown by slow evaporation solution technique. In the present work, to improve the crystalline quality of lithium sulfate monohydrate crystal, metal dopant was incorporated into the pure crystals. The as grown crystals are clear, transparent and the sizes of the crystals were up to 18×12×3 mm3 and 50×15×5 mm3. The presence of metal dopant has been confirmed by energy dispersive spectroscopy, atomic absorption spectroscopy analysis. Single crystal and powder X-ray diffraction studies were carried out to ascertain lattice parameters and identify different phase nature. Optical transmission spectrum of the grown crystals was recorded. FT-IR and thermal analysis were carried out to investigate the functional group and thermal behavior of the grown crystals respectively. The grown crystal was subjected to Vickers micro hardness, HRXRD, piezoelectric, laser damage threshold measurements and second harmonic generation efficiency studies.

  6. The Effects of Gravity on the Crystallization Behavior of Heavy Metal Fluoride Glasses

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Smith, Guy A.

    2004-01-01

    Heavy metal fluoride glasses are used in such applications as fiber lasers and laser amplifiers. ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) is one of the more commonly used heavy metal fluoride glasses. ZBLAN is an infrared transmitter and has a theoretical attenuation coefficient of 0.002 db/km. However, due to impurities and small crystallites this attenuation coefficient has not been achieved to date. ZBLAN is a fragile glass which can lead to rapid crystallization, if the glass is not cooled rapidly to below the glass transition temperature or if the glass is reheated near the crystallization temperature for any period of time. Studies carried on at Marshall Space Flight Center and the University of Alabama in Huntsville since 1993 have shown that heating ZBLAN glass at the crystallization temperature in reduced gravity results in a suppression of crystallization when compared to ZBLAN processed in unit gravity. These studies utilized NASA's KC-135 aircraft and the Conquest sounding rocket. In the first series of experiments, short lengths of ZBLAN fiber were heated to the crystallization temperature in reduced gravity on board the KC- 135 and the Conquest sounding rocket and compared with fibers heated in unit gravity. The fibers processed in reduced gravity showed no evidence of crystallization when studied with x-ray diffraction and scanning electron microscopy. However, the fibers processed in unit gravity were completely crystallized. Subsequent experiments included heating small pieces of ZBLAN glass at the crystallization temperature while viewing with a video camera to follow the crystallization phenomenon. In this experiment crystallization was observed in reduced gravity, however, it was suppressed when compared to heating in unit gravity. In the most recent experiment on board the KC-135, rapid thermal analysis of ZBLAN was performed. A mechanism to explain the observations has been proposed. This mechanism is based on shear thinning whereby, the glass

  7. Determining the sign of a polar surface of lithium niobate crystal by UV reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Paranin, V. D.; Pantelei, E.

    2017-01-01

    We propose to reveal the + Z and- Z surfaces of a polar cut lithium niobate crystal by measuring its UV reflection spectrum. By the example of a congruent lithium niobate, it is shown that the intensities of light reflection from polar crystal surfaces of different signs in the region of 190—260 nm differ by up to several percent. The depth of short-wave radiation penetration into surface layers of the crystal in the spectral range of intrinsic absorption is estimated. It is shown that the proposed method can be used for determining the surface signs of polar crystal layers with thicknesses from several dozen to several hundred microns.

  8. Twin defects in thick stoichiometric lithium tantalate crystals prepared by a vapor transport equilibration method

    NASA Astrophysics Data System (ADS)

    Yang, Jinfeng; Sun, Jun; Xu, Jingjun; Li, Qinglian; Shang, Jifang; Zhang, Ling; Liu, Shiguo; Huang, Cunxin

    2016-01-01

    The twins were observed and investigated in vapor transport equilibration (VTE) treated lithium tantalate crystals by burying congruent lithium tantalate crystals (CLT) in a Li-rich polycrystalline powder. Twins and their etched patterns were observed under an optical polarizing microscope, and the geometry of the twins was discussed. Twin composition planes were the { 01 1 bar 2 } planes. The cause of twinning was analyzed and verified by experiment. The results indicate that the emergence of twins is due to sintering stress, which arises from sintered Li-rich polycrystalline powders at high temperature. 3.2 mm thick stoichiometric lithium tantalate (SLT) crystals without twins were obtained by setting corundum crucibles over the top of the crystals to make crystals free from the sintering stress. In addition, cracks were observed at the intersection of twin bands, and the stress caused by the dislocation pile-up was considered to be the reason for the formation of cracks.

  9. Sulfonic Acid- and Lithium Sulfonate-Grafted Poly(Vinylidene Fluoride) Electrospun Mats As Ionic Liquid Host for Electrochromic Device and Lithium-Ion Battery.

    PubMed

    Zhou, Rui; Liu, Wanshuang; Leong, Yew Wei; Xu, Jianwei; Lu, Xuehong

    2015-08-05

    Electrospun polymer nanofibrous mats loaded with ionic liquids (ILs) are promising nonvolatile electrolytes with high ionic conductivity. The large cations of ILs are, however, difficult to diffuse into solid electrodes, making them unappealing for application in some electrochemical devices. To address this issue, a new strategy is used to introduce proton conduction into an IL-based electrolyte. Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) copolymer is functionalized with sulfonic acid through covalent attachment of taurine. The sulfonic acid-grafted P(VDF-HFP) electrospun mats consist of interconnected nanofibers, leading to remarkable improvement in dimensional stability of the mats. IL-based polymer electrolytes are prepared by immersing the modified mats in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(+)BF4(-)). It is found that the SO3(-) groups can have Lewis acid-base interactions with the cations (BMIM(+)) of IL to promote the dissociation of ILs, and provide additional proton conduction, resulting in significantly improved ionic conductivity. Using this novel electrolyte, polyaniline-based electrochromic devices show higher transmittance contrast and faster switching behavior. Furthermore, the sulfonic acid-grafted P(VDF-HFP) electrospun mats can also be lithiated, giving additional lithium ion conduction for the IL-based electrolyte, with which Li/LiCoO2 batteries display enhanced C-rate performance.

  10. Growth of high quality bulk size single crystals of inverted solubility lithium sulphate monohydrate

    SciTech Connect

    Silambarasan, A.; Rajesh, P. Ramasamy, P.

    2015-06-24

    The paper summarizes the processes of growing large lithium sulfate monohydrate (LSMH) single crystals. We have established a procedure to grow high quality bulk size single crystals of inverted solubility LSMH by a newly developed unidirectional crystallization technique called the Sankeranarayenan - Ramasamy (SR) method. The convective flow of crystal growth processes from solution and the conditions of growing crystals of various aspects were discussed. Good quality LSMH single crystal is grown of the size 20 mmX80 mm without cracks, localized-defects and inclusions. The as-grown crystals are suitable for piezoelectric and nonlinear optical applications.

  11. Lithium

    USGS Publications Warehouse

    Jaskula, B.W.

    2010-01-01

    In 2009, lithium consumption in the United States was estimated to have been about 1.2 kt (1,300 st) of contained lithium, a 40-percent decrease from 2008. The United States was estimated to be the fourth largest consumer of lithium, and remained the leading importer of lithium carbonate and the leading producer of value-added lithium materials. Only one company, Chemetall Foote Corp. (a subsidiary of Chemetall GmbH of Germany), produced lithium compounds from domestic resources. In 2009, world lithium consumption was estimated to have been about 18.7 kt (20,600 st) of lithium contained in minerals and compounds.

  12. Lithium

    USGS Publications Warehouse

    Jaskula, B.W.

    2011-01-01

    In 2010, lithium consumption in the United States was estimated to have been about 1 kt (1,100 st) of contained lithium, a 23-percent decrease from 2009. The United States was estimated to be the fourth largest consumer of lithium. It remained the leading importer of lithium carbonate and the leading producer of value-added lithium materials. Only one company, Chemetall Foote Corp. (a subsidiary of Chemetall GmbH of Germany), produced lithium compounds from domestic resources. In 2010, world lithium consumption was estimated to have been about 21 kt (22,000 st) of lithium contained in minerals and compounds, a 12-percent increase from 2009.

  13. Lithium-free transition metal monoxides for positive electrodes in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Jung, Sung-Kyun; Kim, Hyunchul; Cho, Min Gee; Cho, Sung-Pyo; Lee, Byungju; Kim, Hyungsub; Park, Young-Uk; Hong, Jihyun; Park, Kyu-Young; Yoon, Gabin; Seong, Won Mo; Cho, Yongbeom; Oh, Myoung Hwan; Kim, Haegyeom; Gwon, Hyeokjo; Hwang, Insang; Hyeon, Taeghwan; Yoon, Won-Sub; Kang, Kisuk

    2017-01-01

    Lithium-ion batteries based on intercalation compounds have dominated the advanced portable energy storage market. The positive electrode materials in these batteries belong to a material group of lithium-conducting crystals that contain redox-active transition metal and lithium. Materials without lithium-conducting paths or lithium-free compounds could be rarely used as positive electrodes due to the incapability of reversible lithium intercalation or the necessity of using metallic lithium as negative electrodes. These constraints have significantly limited the choice of materials and retarded the development of new positive electrodes in lithium-ion batteries. Here, we demonstrate that lithium-free transition metal monoxides that do not contain lithium-conducting paths in their crystal structure can be converted into high-capacity positive electrodes in the electrochemical cell by initially decorating the monoxide surface with nanosized lithium fluoride. This unusual electrochemical behaviour is attributed to a surface conversion reaction mechanism in contrast with the classic lithium intercalation reaction. Our findings will offer a potential new path in the design of positive electrode materials in lithium-ion batteries.

  14. Instability of Polyvinylidene Fluoride-Based Polymeric Binder in Lithium-Ion Cells: Final Report

    SciTech Connect

    Garcia, M.; Nagasubramanian, G.; Tallant, D.R.; Roth, E.P.

    1999-05-01

    Thermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100 degree C involving the solid electrolyte interface (SEI) layer and the LiPF(6) salt in the electrolyte (EC-PC:DEC/IM LiPF(6)). These reactions could account for the thermal runaway observed in these cells beginning at 100 degree C. Exothermic reactions were also observed in the 200 degree C to 300 degree C region between the intercalated lithium anodes, the LiPF(6) salt, and the PVDF. These reactions were followed by a high-temperature reaction region, 300 degree C to 400 degree C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medium. Cathode exothermic reactions with the PVDF binder were observed above 200 degree C and increased with the state of charge (decreasing Li content). The stability of the PVDF binder as a function of electrochemical cycling was studied using FTIR. The infrared spectra from the extracts of both electrodes indicate that PVDF is chemically modified by exposure to the lithium cell electrolyte (as well as electrochemical cycling) in conjunction with NMP extraction. Preconditioning of PVDF to dehydrohalogenation, which may be occurring by reaction with LiPf(6), makes the PVDF susceptible to attack by a range of nucleophiles.

  15. Impact of Nanosilicates on Poly(vinylidene fluoride) Crystal Polymorphism: Part 1. Melt-crystallization at High Supercooling

    SciTech Connect

    Ince-Gunduz, B.; Alpern, R; Amare, D; Crawford, J; Dolan, B; Jones, S; Kobylarz, R; Reveley, M; Cebe, P

    2010-01-01

    Polymorphism of poly(vinylidene fluoride), PVDF, in the presence of Lucentite STN organically modified silicate (OMS) is investigated for PVDF nanocomposites melt-crystallized at high supercooling temperatures where neat PVDF crystallizes exclusively in the alpha crystalline phase. Nanocomposites were prepared from solution with 0-1.0 wt% OMS composition. Here we observed that clay addition promotes gamma phase formation in nanocomposites melt-crystallized at high supercooling (i.e., at low crystallization temperature), whereas previously we showed that even small amount of nanosilicates resulted in beta phase formation in cold-crystallized PVDF nanocomposites. Wide-angle X-ray scattering (WAXS), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) studies showed that {alpha}- and {gamma}-phases co-existed in nanocomposites containing up to 0.1 wt% OMS, and the amount of {alpha}-crystals substantially diminished for higher OMS content. Formation of {gamma}-crystal phase was confirmed with morphologic observation of spherulites of low-birefringence using polarizing optical and atomic force microscopies, and their crystalline structures were verified by FTIR and Raman microscopic spectroscopy. We also address in this work the ambiguities in assessing PVDF crystallographic phases, and correct the phase identification errors which have persisted up to this point in the literature based on melting point confusion. The crystal phase identification for PVDF nanocomposites is discussed and clarified, based on X-ray scattering, vibrational spectra, and thermal analysis. For reference, we provide a vibrational band list, indicating the close, or overlapping bands, of the three phases of PVDF: {alpha}, {beta} and {gamma}.

  16. Polishing test of a poly-crystal calcium fluoride lens: toward the development of TMT WFOS

    NASA Astrophysics Data System (ADS)

    Ozaki, Shinobu; Miyazaki, Satoshi; Tsuzuki, Toshihiro; Tanaka, Yoko

    2016-08-01

    Wide-Field Optical Spectrograph (WFOS) is one of the first-light instruments of Thirty Meter Telescope (TMT), and developed in an international collaboration led by University of California Santa Cruz. It covers the wavelength range from 310 nm to 1 μm which is divided at around 550 nm by a dichroic mirror. Calcium Fluoride (CaF2) is very useful to reduce aberration and has good transmittance even at 310 nm. Because a large mono-crystal CaF2 is difficult to be manufactured, we might have to use a poly-crystal CaF2. Comparing a mono-crystal, the poly-crystal is expected to have worse optical index homogeneity and larger surface figure error after polishing. Those effects on an image quality are unclear. To verify those effects, we conducted a polishing test of a small poly-crystal CaF2 lens as a first step. As a result, we found figure error around the boundary. The figure error is 139 nm PV and 26 nm RMS. Comparing a Zemax simulation, it is confirmed that the figure error does not have significant effect on the image quality.

  17. Ferroelectric properties of vinylidene fluoride/tetrafluoroethylene copolymer thin films consisting of needle-like crystals

    NASA Astrophysics Data System (ADS)

    Nakagawa, Yuuta; Hashizume, Yoichiro; Nakajima, Takashi; Okamura, Soichiro

    2016-05-01

    Unique ferroelectric vinylidene fluoride (VDF)/tetrafluoroethylene (TeFE) copolymer thin films consisting of needle-like crystals were formed using Au-sputtered substrates. The VDF/TeFE films with a mixing ratio of 80:20 mol % were melted at 170 °C for 30 min and then recrystallized at 116 °C for 300 min. The molecules in the resultant needle-like crystals had a β-phase form and showed 200/110 orientation, while the direction of each needle-like crystal was random in-plane. The remanent polarization of the 450-nm-thick VDF/TeFE films consisting of the needle-like crystals were estimated to be 62 mC/m2 from the electric displacement vs electric field (D-E) hysteresis measurement at the applied field of 156 MV/m and the frequency of 10 Hz. The remanent polarization of 62 mC/m2 was approximately 50% larger than that of conventional VDF/TeFE films consisting of plate-like crystals.

  18. Low operating voltage n-channel organic field effect transistors using lithium fluoride/PMMA bilayer gate dielectric

    SciTech Connect

    Kumar, S.; Dhar, A.

    2015-10-15

    Highlights: • Alternative to chemically crosslinking of PMMA to achieve low leakage in provided. • Effect of LiF in reducing gate leakage through the OFET device is studied. • Effect of gate leakage on transistor performance has been investigated. • Low voltage operable and low temperature processed n-channel OFETs were fabricated. - Abstract: We report low temperature processed, low voltage operable n-channel organic field effect transistors (OFETs) using N,N′-Dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C{sub 8}) organic semiconductor and poly(methylmethacrylate) (PMMA)/lithium fluoride (LiF) bilayer gate dielectric. We have studied the role of LiF buffer dielectric in effectively reducing the gate leakage through the device and thus obtaining superior performance in contrast to the single layer PMMA dielectric devices. The bilayer OFET devices had a low threshold voltage (V{sub t}) of the order of 5.3 V. The typical values of saturation electron mobility (μ{sub s}), on/off ratio and inverse sub-threshold slope (S) for the range of devices made were estimated to be 2.8 × 10{sup −3} cm{sup 2}/V s, 385, and 3.8 V/decade respectively. Our work thus provides a potential substitution for much complicated process of chemically crosslinking PMMA to achieve low leakage, high capacitance, and thus low operating voltage OFETs.

  19. Thin-film encapsulation of organic electronic devices based on vacuum evaporated lithium fluoride as protective buffer layer

    NASA Astrophysics Data System (ADS)

    Peng, Yingquan; Ding, Sihan; Wen, Zhanwei; Xu, Sunan; Lv, Wenli; Xu, Ziqiang; Yang, Yuhuan; Wang, Ying; Wei, Yi; Tang, Ying

    2017-03-01

    Encapsulation is indispensable for organic thin-film electronic devices to ensure reliable operation and long-term stability. For thin-film encapsulating organic electronic devices, insulating polymers and inorganic metal oxides thin films are widely used. However, spin-coating of insulating polymers directly on organic electronic devices may destroy or introduce unwanted impurities in the underlying organic active layers. And also, sputtering of inorganic metal oxides may damage the underlying organic semiconductors. Here, we demonstrated that by utilizing vacuum evaporated lithium fluoride (LiF) as protective buffer layer, spin-coated insulating polymer polyvinyl alcohol (PVA), and sputtered inorganic material Er2O3, can be successfully applied for thin film encapsulation of copper phthalocyanine (CuPc)-based organic diodes. By encapsulating with LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films, the device lifetime improvements of 10 and 15 times can be achieved. These methods should be applicable for thin-film encapsulation of all kinds of organic electronic devices. Moisture-induced hole trapping, and Al top electrode oxidation are suggest to be the origins of current decay for the LiF/PVA/LiF trilayer and LiF/Er2O3 bilayer films encapsulated devices, respectively.

  20. Photoluminescence of radiation-induced color centers in lithium fluoride thin films for advanced diagnostics of proton beams

    SciTech Connect

    Piccinini, M. Ampollini, A.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Vincenti, M. A.; Montereali, R. M.; Ambrosini, F.; Nichelatti, E.

    2015-06-29

    Systematic irradiation of thermally evaporated 0.8 μm thick polycrystalline lithium fluoride films on glass was performed by proton beams of 3 and 7 MeV energies, produced by a linear accelerator, in a fluence range from 10{sup 11} to 10{sup 15} protons/cm{sup 2}. The visible photoluminescence spectra of radiation-induced F{sub 2} and F{sub 3}{sup +} laser active color centers, which possess almost overlapping absorption bands at about 450 nm, were measured under laser pumping at 458 nm. On the basis of simulations of the linear energy transfer with proton penetration depth in LiF, it was possible to obtain the behavior of the measured integrated photoluminescence intensity of proton irradiated LiF films as a function of the deposited dose. The photoluminescence signal is linearly dependent on the deposited dose in the interval from 10{sup 3} to about 10{sup 6 }Gy, independently from the used proton energies. This behavior is very encouraging for the development of advanced solid state radiation detectors based on optically transparent LiF thin films for proton beam diagnostics and two-dimensional dose mapping.

  1. White light upconversion emission in Yb3+/ Er3+/ Tm3+ codoped oxy-fluoride lithium tungsten tellurite glass ceramics

    NASA Astrophysics Data System (ADS)

    Ansari, Ghizal F.; Mahajan, S. K.

    2012-02-01

    The bright white upconversion emission ( tri-colour UC) is generated in Er/Tm/Yb tri -doped oxy-fluoride lithium tungsten tellurite (TWLOF)glass ceramics containing crystalline phase LiYbF4 under the excitation of 980nm laser diode. The most appropriate combination of rare-earth ions (2mol% YbF3 1mol% ErF3 and 1mol%TmF3 )of glass ceramic sample has been determined to tune the primary colour (RGB and generate white light emission. By varying the pump power, intense and weak blue (487nm, 437nm), green (525nm and 545nm) and red (662nm) emission are simultaneously observed at room temperature. The dependence of upconversion emission intensity suggest that a theephoton process is responsible for the blue emission of Tm3+ ions and red emission due to both Tm3+ and Er3+ ions , while green emission originated from two photon processes in Er3+ ions. Also tri colour upconvesion and energy transfer in this glass ceramics sample were studied under 808nm laser diode excitation. The Upconversion mechanisms and Tm3+ ions plays role of both emitter and activator (transfer energy to Er) were discussed.

  2. Lithium

    USGS Publications Warehouse

    Jaskula, B.W.

    2012-01-01

    In 2011, world lithium consumption was estimated to have been about 25 kt (25,000 st) of lithium contained in minerals and compounds, a 10-percent increase from 2010. U.S. consumption was estimated to have been about 2 kt (2,200 st) of contained lithium, a 100-percent increase from 2010. The United States was estimated to be the fourth-ranked consumer of lithium and remained the leading importer of lithium carbonate and the leading producer of value-added lithium materials. One company, Chemetall Foote Corp. (a subsidiary of Chemetall GmbH of Germany), produced lithium compounds from domestic brine resources near Silver Peak, NV.

  3. Lithium

    USGS Publications Warehouse

    Ober, J.A.

    2006-01-01

    In 2005, lithium consumption in the United States was at 2.5 kt of contained lithium, nearly 32% more than the estimate for 2004. World consumption was 14.1 kt of lithium contained in minerals and compounds in 2003. Exports from the US increased slightly compared with 2004. Due to strong demand for lithium compounds in 2005, both lithium carbonate plants in Chile were operating at or near capacity.

  4. Crystal and electronic structures of neptunium nitrides synthesized using a fluoride route.

    PubMed

    Silva, G W Chinthaka; Weck, Philippe F; Kim, Eunja; Yeamans, Charles B; Cerefice, Gary S; Sattelberger, Alfred P; Czerwinski, Kenneth R

    2012-02-15

    A low-temperature fluoride route was utilized to synthesize neptunium mononitride, NpN. Through the development of this process, two new neptunium nitride species, NpN(2) and Np(2)N(3), were identified. The NpN(2) and Np(2)N(3) have crystal structures isomorphous to those of UN(2) and U(2)N(3), respectively. NpN(2) crystallizes in a face-centered cubic CaF(2)-type structure with a space group of Fm3m and a refined lattice parameter of 5.3236(1) Å. The Np(2)N(3) adopts the body-centered cubic Mn(2)O(3)-type structure with a space group of Ia3. Its refined lattice parameter is 10.6513(4) Å. The NpN synthesis at temperatures ≤900 °C using the fluoride route discussed here was also demonstrated. Previous computational studies of the neptunium nitride system have focused exclusively on the NpN phase because no evidence was reported experimentally on the presence of NpN(x) systems. Here, the crystal structures of NpN(2) and Np(2)N(3) are discussed for the first time, confirming the experimental results by density functional calculations (DFT). These DFT calculations were performed within the local-density approximation (LDA+U) and the generalized-gradient approximation (GGA+U) corrected with an effective Hubbard parameter to account for the strong on-site Coulomb repulsion between Np 5f electrons. The effects of the spin-orbit coupling in the GGA+U calculations have also been investigated for NpN(2) and NpN.

  5. Crystal and Electronic Structures of Neptunium Nitrides Synthesized Using a Fluoride Route

    SciTech Connect

    Silva, G W Chinthaka M; Weck, Dr. Phil F.; Eunja, Dr. Kim; Yeamans, Dr. Charles B.; Cerefice, Gary S.; Sattelberger, Alfred P; Czerwinski, Ken R.

    2012-01-01

    A low-temperature fluoride route was utilized to synthesize neptunium mononitride, NpN. Through the development of this process, two new neptunium nitride species, NpN{sub 2} and Np{sub 2}N{sub 3}, were identified. The NpN{sub 2} and Np{sub 2}N{sub 3} have crystal structures isomorphous to those of UN{sub 2} and U{sub 2}N{sub 3}, respectively. NpN{sub 2} crystallizes in a face-centered cubic CaF{sub 2}-type structure with a space group of Fm3m and a refined lattice parameter of 5.3236(1) {angstrom}. The Np{sub 2}N{sub 3} adopts the body-centered cubic Mn{sub 2}O{sub 3}-type structure with a space group of Ia{bar 3}. Its refined lattice parameter is 10.6513(4) {angstrom}. The NpN synthesis at temperatures {le} 900 C using the fluoride route discussed here was also demonstrated. Previous computational studies of the neptunium nitride system have focused exclusively on the NpN phase because no evidence was reported experimentally on the presence of NpN{sub x} systems. Here, the crystal structures of NpN{sub 2} and Np{sub 2}N{sub 3} are discussed for the first time, confirming the experimental results by density functional calculations (DFT). These DFT calculations were performed within the local-density approximation (LDA+U) and the generalized-gradient approximation (GGA+U) corrected with an effective Hubbard parameter to account for the strong on-site Coulomb repulsion between Np 5f electrons. The effects of the spin-orbit coupling in the GGA+U calculations have also been investigated for NpN{sub 2} and NpN.

  6. Effect of Preparation Methods on Crystallization Behavior and Tensile Strength of Poly(vinylidene fluoride) Membranes

    PubMed Central

    Liu, Jie; Lu, Xiaolong; Wu, Chunrui

    2013-01-01

    Poly(vinylidene fluoride) (PVDF) membranes were prepared by non solvent induced phase separation (NIPS), melt spinning and the solution-cast method. The effect of preparation methods with different membrane formation mechanisms on crystallization behavior and tensile strength of PVDF membranes was investigated. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and X-ray diffraction (XRD) were employed to examine the crystal form of the surface layers and the overall membranes, respectively. Spherulite morphologies and thermal behavior of the membranes were studied by polarized light optical microscopy (PLO) and differential scanning calorimetry (DSC) separately. It was found that the crystallization behavior of PVDF membranes was closely related to the preparation methods. For membranes prepared by the NIPS method, the skin layers had a mixture of α and β phases, the overall membranes were predominantly α phase, and the total crystallinity was 60.0% with no spherulite. For melt spinning membranes, the surface layers also showed a mixture of α and β phases, the overall membranes were predominantly α phase. The total crystallinity was 48.7% with perfect spherulites. Whereas the crystallization behavior of solution-cast membranes was related to the evaporation temperature and the additive, when the evaporation temperature was 140 °C with a soluble additive in the dope solution, obvious spherulites appeared. The crystalline morphology of PVDF exerted a great influence on the tensile strength of the membranes, which was much higher with perfect spherulites. PMID:24957064

  7. Tunable Bloch surface waves in anisotropic photonic crystals based on lithium niobate thin films.

    PubMed

    Kovalevich, Tatiana; Ndao, Abdoulaye; Suarez, Miguel; Tumenas, Saulius; Balevicius, Zigmas; Ramanavicius, Arunas; Baleviciute, Ieva; Häyrinen, Markus; Roussey, Matthieu; Kuittinen, Markku; Grosjean, Thierry; Bernal, Maria-Pilar

    2016-12-01

    We present an original type of one-dimensional photonic crystal that includes one anisotropic layer made of a lithium niobate thin film. We demonstrate the versatility of such a device sustaining different Bloch surface waves (BSWs), depending on the orientation of the incident wave. By varying the orientation of the illumination of the multilayer, we measured an angle variation of 7° between the BSWs corresponding to the extraordinary and the ordinary index of the lithium niobate thin film. The potential of such a platform opens the way to novel tunable and active planar optics based on the electro- and thermo-optical properties of lithium niobate.

  8. [H 3tren] 3+ templated iron fluorides; synthesis, crystal structures and Mössbauer studies

    NASA Astrophysics Data System (ADS)

    Ali, Amor Ben; Grenèche, Jean-Marc; Leblanc, Marc; Maisonneuve, Vincent

    2009-09-01

    The hydrothermal synthesis, using tris-(2-ethylamino)amine ( tren) as a template, and the crystal structures of three new hybrid iron fluorides, (H 3O) 2·[H 3tren] 2·(FeF 6) 2·(FeF 5(H 2O))·2H 2O ( I), [H 3tren] 2·(FeF 6) 2·(FeF 2(H 2O) 4)·8H 2O ( II) and [H 3tren] 2·(FeF 6)·(F) 3·H 2O ( III), are reported. I, II, and III are triclinic ( P-1), monoclinic ( P2 1/ c) and orthorhombic ( I222), respectively. The structure of I is built up from isolated FeF 6 and FeF 5(H 2O) distorted octahedra separated by triprotonated [H 3tren] 3+ cations, disordered H 3O + cations and H 2O molecules. In II, Fe IIIF 6 and neutral [Fe IIF 2(H 2O) 4] octahedra form, together with [H 3tren] 3+ cations, infinite (100) layers separated by extra water molecules. The structure of III consists of isolated and disordered FeF 6 octahedra, fluoride anions F - connected to [H 3tren] 3+ cations and extra fluoride anions F - disordered with H 2O molecules. All [H 3tren] 3+ cations have a "spider" type conformation. 57Fe Mössbauer characterization shows that +III valence state can only be considered for iron cations in I and III and preliminary Mössbauer results are consistent with the presence of both +II and +III valences for iron cations in II, in agreement with the crystallographic results.

  9. Microporous gel electrolytes based on amphiphilic poly(vinylidene fluoride-co-hexafluoropropylene) for lithium batteries

    NASA Astrophysics Data System (ADS)

    Yu, Shicheng; Chen, Lie; Chen, Yiwang; Tong, Yongfen

    2012-03-01

    Poly(vinylidene fluoride-co-hexafluoropropylene) grafted poly(poly(ethylene glycol) methyl ether methacrylate) (PVDF-HFP-g-PPEGMA) is simply prepared by single-step synthesis directly via atom transfer radical polymerization (ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA) from poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Thermal, mechanical, swelling and electrochemical properties, as well as microstructures of the prepared polymer electrolytes, are evaluated and the effects of the various contents and average molecular weights of PEGMA on those properties are also been investigated. By phase inversion technique, the copolymer membranes tend to form well-defined microporous morphology with the increase of content and average molecular weight of PEGMA, due to the competition and cooperation between the hydrophilic PEGMA segments and hydrophobic PVDF-HFP. When these membranes are gelled with 1 M LiCF3SO3 in ethylene carbonate (EC)/propylene carbonate (PC) (1:1, v/v), their saturated electrolyte uptakes (up to 323.5%) and ion conductivities (up to 2.01 × 10-3 S cm-1) are dramatically improved with respect to the pristine PVDF-HFP, ascribing to the strong affinity of the hydrophilic PEGMA segments with the electrolytes. All the polymer electrolytes are electrochemically stable up to 4.7 V versus Li/Li+, and show good mechanical properties. Coin cells based on the polymer electrolytes show stable charge-discharge cycles and deliver discharge capacities to LiFePO4 is up to 156 mAh g-1.

  10. Growth of lithium triborate single crystals from molten salt solution under various temperature gradients

    NASA Astrophysics Data System (ADS)

    Guretskii, S. A.; Ges, A. P.; Zhigunov, D. I.; Ignatenko, A. A.; Kalanda, N. A.; Kurnevich, L. A.; Luginets, A. M.; Milovanov, A. S.; Molchan, P. V.

    1995-12-01

    Single crystals of lithium triborate LiB 3O 5 (LBO) have been grown by the top-seeded solution growth method with B 2O 3 as a solvent using different temperature gradients in the zone of crystallization. Optical and nonlinear optical properties of LBO single crystals have been investigated. The influence of post-growth thermal treatment in oxygen atmosphere on the optical properties has been studied.

  11. Effect of additives on size and shape of lithium carbonate crystals

    NASA Astrophysics Data System (ADS)

    Taborga, P.; Brito, I.; Graber, T. A.

    2017-02-01

    Generally, properties such internal structure, shape, and size distribution influence the reactivity, fluidity and wettability of the crystals, and may be modified by the use of additives such as polyelectrolytes or surfactants. The aim of this study was to investigate the effect of different additives on the size and morphology of lithium carbonate crystals obtained by reactive crystallization from solutions of LiCl and Na2CO3. The additives used were: polyethylenimine (PEI), polyethylene glycol (PEG), poly (4-styrenesulfonic acid), (P4SA), polyacrylic acid (PAA), sodium dodecyl sulfate (SDS), and sodium dodecyl benzenesulfonate (SDBS). Obtained crystals were observed using scanning electron microscopy, the crystal size distribution was determined by a size image analyzer, and the crystal structure were analyzed by X-ray diffraction. The results showed that the presence of PEI, PEG and P4SA, increased the length of the lithium carbonate particles. The presence of SDS decreases the crystals size. Using SDBS as additive, the crystals had a needle-like shape, Finally PAA allowed the production of Li2CO3 spherulites. Crystal structure of lithium carbonate did not change in the presence of the tested additives.

  12. High index fluoride materials for 193nm immersion lithography

    NASA Astrophysics Data System (ADS)

    Nawata, T.; Inui, Y.; Masada, I.; Nishijima, E.; Satoh, H.; Fukuda, T.

    2006-03-01

    We tried to investigate various kinds of metal fluoride materials which have higher gravity than CaF II and cubic crystal system, and we found out barium lithium fluoride (BaLiF 3) and potassium yttrium fluoride (KY 3F 10) as candidates for the last lens material. We have developed unique Czochralski (CZ) machines and techniques for the growth of large calcium fluoride single crystals. And we applied these technologies to the growth of fluoride high index materials. We have succeeded to grow the large BaLiF 3 single crystal with 120mm in diameter and a KY 3F 10 single crystal, and measured their basic properties such as refractive index, VUV transmittance, birefringence, and so on. As a result of our basic research, we found out that BaLiF 3 single crystal is transparent at VUV region, and the refractive index at 193nm is 1.64, and KY 3F 10 single crystal has the index of 1.59 at the wavelength of 193nm which is slightly higher than fused silica. We expect that these fluoride high index materials are useful for the last lens material of the next generation immersion lithography.

  13. Elastic properties of poly(vinyldene fluoride) (PVDF) crystals: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Pei, Yong; Zeng, Xiao Cheng

    2011-05-01

    We computed structural and elastic properties of totally nine phases of poly(vinyldene fluoride) (PVDF) crystals using the density-functional theory (DFT) method with and without inclusion of the dispersion corrections. In addition to the four known crystalline forms, mechanic properties of five theoretically predicted crystalline forms of PVDF are also investigated. The all-trans form Ip exhibits the largest cohesive energy, bulk, and Young's modulus among the nine crystalline forms. The DFT calculations suggest that the δ crystalline forms (IIIau, IIIpu, IIIpd, and IIIad) possess poor chain rigidity among the nine PVDF crystalline forms. In contrast, a change of relative orientation of PVDF chains does not lead to significant change in cohesive energy and mechanic properties. A comparison of the cohesive energies of nine crystalline forms of PVDF suggests that the theoretically proposed crystalline forms of PVDF are quite stable.

  14. Cation-controlled crystal growth of silver stearate: cryo-TEM investigation of lithium vs sodium stearate.

    PubMed

    Dong, Jingshan; McCormick, Alon V; Davis, H Ted; Whitcomb, David R

    2010-02-16

    Cryo-TEM, SAXS, and light microscopy techniques were used to probe the morphology and kinetics of silver stearate self-assembly and crystallization from the reaction of silver nitrate with lithium stearate. Unlike the reaction of sodium stearate with silver nitrate, which proceeds via micelle aggregation, the lithium stearate forms vesicles that drastically change the reaction kinetics of the silver stearate nucleation and self-assembly process. In addition, even with excess silver nitrate present, only about 80% of the lithium stearate can be converted to silver stearate. The presence of the residual lithium stearate inhibits the silver stearate crystal growth process. Consequently, no silver stearate micelle aggregates of any significant size form, unlike the system utilizing sodium stearate. Instead, significantly smaller silver stearate crystals result from lithium stearate compared to the silver stearate crystals from sodium stearate and provide an opportunity to further control silver stearate self-assembly and crystal growth.

  15. Freestanding manganese dioxide nanosheet network grown on nickel/polyvinylidene fluoride coaxial fiber membrane as anode materials for high performance lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Luo, Zhongping; Xiao, Qizhen; Sun, Tianlei; Lei, Gangtie; Li, Zhaohui; Li, Xiaojing

    2015-11-01

    A novel manganese dioxide (MnO2) nanosheet network grown on nickel/polyvinylidene fluoride (Ni/PVDF) coaxial fiber membrane is successfully fabricated by a three-step route: the polyvinylidene fluoride fiber membrane is prepared by electrospinning method, and then the Ni(shell)/PVDF(core) coaxial fiber membrane with core-shell structure can be obtained by the electroless deposition, and finally the manganese dioxide nanosheet network grown on Ni/PVDF coaxial fiber membrane can be achieved by using a simple hydrothermal treatment. This as-prepared binder-free and flexible composite membrane is directly used as anode for lithium ion batteries. The excellent electrochemical performance of the composite membrane can be attributed to the unique combinative effects of nanosized MnO2 network and conductive Ni/PVDF fiber matrix as well as the porous structure of composite fiber membrane.

  16. Lithium

    USGS Publications Warehouse

    Ober, J.

    1998-01-01

    The lithium industry can be divided into two sectors: ore concentrate producers and chemical producers. Ore concentrate producers mine lithium minerals. They beneficiate the ores to produce material for use in ceramics and glass manufacturing.

  17. Optimizing the performance of bandpass photon detectors for inverse photoemission: Transmission of alkaline earth fluoride window crystals

    SciTech Connect

    Thiede, Christian Schmidt, Anke B.; Donath, Markus

    2015-08-15

    Bandpass photon detectors are widely used in inverse photoemission in the isochromat mode at energies in the vacuum-ultraviolet spectral range. The energy bandpass of gas-filled counters is usually formed by the ionization threshold of the counting gas as high-pass filter and the transmission cutoff of an alkaline earth fluoride window as low-pass filter. The transmission characteristics of the window have, therefore, a crucial impact on the detector performance. We present transmission measurements in the vacuum-ultraviolet spectral range for alkaline earth fluoride window crystals in the vicinity of the transmission cutoff as a function of crystal purity, surface finish, surface contamination, temperature, and thickness. Our findings reveal that the transmission characteristics of the window crystal and, thus, the detector performance depend critically on these window parameters.

  18. Study on effect of poly (ethylene oxide) addition and in-situ porosity generation on poly (vinylidene fluoride)-glass ceramic composite membranes for lithium polymer batteries

    NASA Astrophysics Data System (ADS)

    Shubha, Nageswaran; Prasanth, Raghavan; Hng, Huey Hoon; Srinivasan, Madhavi

    2014-12-01

    The effect of blending polyethylene oxide with poly (vinylidene fluoride)-lithium aluminum germanium phosphate (LAGP) composite and in-situ porosity generation on the electrochemical performance of polymer electrolytes based on non-woven fibrous mats is studied. Electrospinning process parameters are controlled to get a fibrous membrane consisting of bead-free, multilayered, three dimensional network structure of ultrafine fibers. The electrospun membranes are subjected to a preferential polymer dissolution process to prepare a highly porous structure. The membranes show high surface roughness with uniformly sized and distributed pores on the fibers. The membranes with good mechanical strength, thermal stability and high porosity exhibit high swelling when activated with liquid electrolyte. The prepared composite polymer electrolytes show high ionic conductivity. The addition of the glass ceramic improves the mechanical and thermal stability, while blending and in-situ porosity generation improves the ionic conductivity, charge-discharge performance, cycling stability, interface properties and compatibility with lithium electrode.

  19. Growth, Structural And Optical Studies On Bis L-alanine Lithium Chloride (BLALC) Single Crystal

    NASA Astrophysics Data System (ADS)

    Rose, A. S. J. Lucia; Selvarajan, P.; Perumal, S.

    2011-10-01

    Bis L-alanine Lithium Chloride (BLALC) single crystals were grown successfully by solution method with slow evaporation technique at room temperature. Crystals of size 15 x 9 x 4 mm3 have been obtained in 28 days. The grown crystals were colourless and transparent. Single crystal X-ray diffraction (XRD) study showed that BLALC belongs to orthorhombic system with a non-centro-symmetric space group P212121. The crystallinity of BLALC crystal was confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. The functional groups of the grown crystals have been identified by FTIR studies. UV-visible transmittance spectrum was recorded to study the optical transparency of BLALC crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz-Perry powder technique.

  20. RETRACTED: Crystal growth and spectroscopic characterization of Aloevera amino acid added lithium sulfate monohydrate: A non-linear optical crystal

    NASA Astrophysics Data System (ADS)

    Manimekalai, R.; Antony Joseph, A.; Ramachandra Raja, C.

    2014-03-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal. This article has been retracted at the request of authors. According to the author we have reported Aloevera Amino Acid added Lithium sulphate monohydrate [AALSMH] crystal is a new nonlinear optical crystal. From the recorded high performance liquid chromatography spectrum, by matching the retention times with the known compounds, the amino acids present in our extract are identified as homocystine, isoleucine, serine, leucine and tyrosine. From the thin layer chromatography and colorimetric estimation techniques, presence of isoleucine was identified and it was also confirmed by NMR spectrum. From the above studies, we came to conclude that AALSMH is new nonlinear optical crystal. After further investigation, lattice parameter values of AALSMH are coinciding with lithium sulphate. Therefore we have decided to withdraw our paper. Sorry for the inconvenience and time spent.

  1. Dynamics of dipolar defects in rare earth-doped alkaline-earth fluoride crystals

    NASA Astrophysics Data System (ADS)

    Charnock, Forrest Taylor

    Alkaline-earth fluoride crystals such as SrF2 provide an excellent sample material for investigating the physics of point defects in crystal lattices. High quality crystals are easily grown, and they readily accept many dopant ions into the lattice, particularly rare earth ions. Rare earth dopant ions (typically trivalent) occupy substitutional sites in the lattice by replacing a Sr2+ ion. Due to the extra charge of the rare earth ion, charge compensation is often provided by an extra fluoride ion (F--) located in a nearby interstitial position. If located in the nearest-neighbor (nn) interstitial position, it forms a defect with C4n symmetry; if located in the next-nearest-neighbor (nnn) intersitial position, it forms a defect with C3n symmetry. Given sufficient thermal energy, this interstitial F ion can move to adjacent interstitial sites and hence reorient the defect. The rate w at which the ion moves from one interstitial site to another is well described by a simple Arrhenius expression: w=n0e-E/kT , where n0 is the attack frequency of the F-- and E is the activation energy. This motion can profoundly affect both the electronic polarizability of the material and the polarization of light emitted or absorbed by the rare earth ion. This thesis describes the normal mode motion of interstitial ions which may occupy either nn or nnn interstitial sites. Using electron paramagnetic resonance (EPR), I observed the relative populations of nn and nnn defects in SrF2 doped with Gd3+ as a function of temperature. These measurements show that dipolar reorientation of the nnn F occurs through the nn interstitial position. Not all interstitial F-- motion is thermally driven. Fluorescence depolarization measurements of SrF2:Pr3+ indicate that optically stimulating a Pr3+ may induce interstitial motion of a nn F--. Such motion was confirmed by showing that nn defects in SrF2:Pr3+ may be polarized at very low temperatures when the sample is illuminated with resonant light. I

  2. Non-Isothermal Calorimetric Studies of the Crystallization of Lithium Disilicate Glass

    NASA Technical Reports Server (NTRS)

    Ray, C. S.; Day, D. E.; Huang, W.; Narayan, K. Lakshmi; Cull, T. S.; Kelton, K. F.

    1996-01-01

    The influence of preannealing treatments on the polymorphic crystallization of lithium disilicate glasses is examined. As expected, glasses heated at different rates through the temperature range where there is significant nucleation develop widely different numbers of nuclei. This can dramatically influence the stability and transformation characteristics of the annealed glass. Non-isothermal differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements are demonstrated to be useful to probe the nucleation behavior. The first systematic investigations of particle size effects on the non-isothermal transformation behavior are presented and discussed. Based on DTA and microscopy experiments, we show that small particles of lithium disilicate glasses crystallize primarily by surface crystallization. The relative importance of surface versus volume crystallization is examined by varying particle size, by introducing nucleating agents and by exposing glasses to atmospheres of different water content. These data are analyzed quantitatively using a numerical model developed in a second paper following in this volume.

  3. Microraman and Photorefractivity Study of Hafnium-Doped Lithium Niobate Crystals

    NASA Astrophysics Data System (ADS)

    Galinetto, Pietro; Rossella, Francesco; Minzioni, Paolo; Razzari, Luca; Cristiani, Ilaria; Degiorgio, Vittorio; Kokanyan, Edvard P.

    We present an investigation of the properties of HfO2-doped lithium niobate crystals, in view of their possible utilization as low-photorefractivity crystals for wavelength converters operating at room temperature. MicroRaman measurements indicate that the linewidth of a specific mode can be used as a local indicator of crystal composition, and show that the grown crystals present very good uniformity. The mechanism by which the photorefractivity is strongly reduced when the HfO2 concentration is above 4 mol% is studied by combining measurements of birefringence variation, under green-light illumination, with electrical phototransport data.

  4. Method of forming single crystals of beta silicon carbide using liquid lithium as a solvent

    DOEpatents

    Lundberg, Lynn B.

    1982-01-01

    A method of growing single crystals of beta SiC from solution using molten lithium as a solvent for polycrystalline SiC feed material. Reasonable growth rates are accomplished at temperatures in the range of about 1330.degree. C. to about 1500.degree. C.

  5. Impact of ionic liquid-modified multiwalled carbon nanotubes on the crystallization behavior of poly(vinylidene fluoride).

    PubMed

    Xing, Chenyang; Zhao, Liping; You, Jichun; Dong, Wenyong; Cao, Xiaojun; Li, Yongjin

    2012-07-19

    The impact of pristine multiwalled carbon nanotubes (MWCNTs), an ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and the ionic liquid-modified MWCNTs (IL-MWCNTs) on the crystallization behavior of melt-crystallized poly(vinylidene fluoride) (PVDF) has been investigated. Pristine MWCNTs accelerate crystallization of PVDF as an efficient nucleation agent, while the formed crystals are mainly nonpolar α crystal form with few polar β crystals. Incorporation of only ionic liquid results in depression of the PVDF melt crystallization rate due to the miscibility of IL with PVDF but leads to a higher content of polar crystals (β and γ forms) than MWCNTs. The ionic liquid and MWCNTs show significant synergetic effects on both the nucleation and the formation of polar crystals for PVDF by melt crystallization. Addition of IL-MWCNTs not only improves the MWCNTs dispersion in PVDF matrix but also increases the overall crystallization rate of PVDF drastically. More important, the melt-crystallized PVDF nanocomposites with IL-MWCNTs show 100% polar polymorphs but no α crystal forms. To the best of our knowledge, this is the first report on the achievements of full polar crystal form in the melt-crystallized PVDF without mechanical deformation or electric field. The IL to MWCNTs ratio and the IL-MWCNTs loading content effects on the crystallization behavior of PVDF in the nanocomposites were also studied. It is considered that the specific interactions between >CF2 with the planar cationic imidazolium ring wrapped on the MWCNTs surface lead to the full zigzag conformations of PVDF; thus, nucleation in polar crystals (β and γ forms) lattice is achieved and full polar crystals are obtained by subsequent crystal growth from the nuclei.

  6. One-Step Synthesis of Titanium Oxyhydroxy-Fluoride Rods and Research on the Electrochemical Performance for Lithium-ion Batteries and Sodium-ion Batteries

    NASA Astrophysics Data System (ADS)

    Li, Biao; Gao, Zhan; Wang, Dake; Hao, Qiaoyan; Wang, Yan; Wang, Yongkun; Tang, Kaibin

    2015-10-01

    Titanium oxyhydroxy-fluoride, TiO0.9(OH)0.9F1.2 · 0.59H2O rods with a hexagonal tungsten bronze (HTB) structure, was synthesized via a facile one-step solvothermal method. The structure, morphology, and component of the products were characterized by X-ray powder diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), inductively coupled plasma optical emission spectroscopy (ICP-OES), ion chromatograph, energy-dispersive X-ray (EDX) analyses, and so on. Different rod morphologies which ranged from nanoscale to submicron scale were simply obtained by adjusting reaction conditions. With one-dimension channels for Li/Na intercalation/de-intercalation, the electrochemical performance of titanium oxyhydroxy-fluoride for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) was also studied. Electrochemical tests revealed that, for LIBs, titanium oxyhydroxy-fluoride exhibited a stabilized reversible capacity of 200 mAh g-1 at 25 mA g-1 up to 120 cycles in the electrode potential range of 3.0-1.2 V and 140 mAh g-1 at 250 mA g-1 up to 500 cycles, especially; for SIBs, a high capacity of 100 mAh g-1 was maintained at 25 mA g-1 after 115 cycles in the potential range of 2.9-0.5 V.

  7. Influence of sodium fluoride (NaF) on the crystallization and spectral properties of L-tyrosine

    NASA Astrophysics Data System (ADS)

    Thenmozhi, M.; Suguna, K.; Sekar, C.

    2011-12-01

    L-Tyrosine (C 9H 11NO 3) is an essential amino acid in living organisms. It is also a building unit in protein, takes part in bio-synthesis of hormones, neurotransmitters, pigments and one of the organic chemical constituents of urinary stones. L-Tyrosine has been crystallized in silica gel by double diffusion technique with and without the addition of NaF. The crystals had rosette-like shape. In case of fluoride addition, two types of crystals have formed: rosette like crystallites, at the gel-solution interface and reticulate type crystallites beneath the interface. XRD results confirmed that both the products are of L-tyrosine with identical crystal structures. Crystal structure, morphology, thermal and spectral properties are analyzed using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR) and UV-vis transmittance studies. The TG-DTA results suggest that the thermal stability of L-tyrosine has markedly improved due to fluoride doping. Optical band gap energy of NaF grown L-tyrosine crystallite is estimated as 4.28 eV. Second harmonic generation efficiency test indicates that L-tyrosine crystals can be used for application in nonlinear optical devices.

  8. Zirconium dioxide nanofilled poly(vinylidene fluoride-hexafluoropropylene) complexed with lithium trifluoromethanesulfonate as composite polymer electrolyte for electrochromic devices

    SciTech Connect

    Puguan, John Marc C.; Chinnappan, Amutha; Kostjuk, Sergei V.; Kim, Hern

    2015-09-15

    Highlights: • Successful synthesis of electrolyte by blending PVdF-HFP, ZrO{sub 2} and LiCF{sub 3}SO{sub 3}. • ZrO{sub 2} increased electrolyte conductivity by two orders of magnitude. • ZrO{sub 2} doubled bulk mechanical strength of electrolyte in terms of Young’s modulus. • Electrolytes gave a optimum optical transmittance of 52.6%. - Abstract: Poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) polymer electrolyte containing zirconium dioxide nanocrystals (ZrO{sub 2}-NC) and lithium trifluoromethanesulfonate (LiCF{sub 3}SO{sub 3}) has been synthesized using the conventional solution casting method. The addition of ZrO2-NC into the polymeric substrate gave remarkable properties in terms of the electrolyte’s ionic conductivity as well as its bulk mechanical strength. The enhanced amorphicity of the polymeric substrate due to ZrO{sub 2} and the nanofiller’s high dielectric constant make an excellent combination to increase the ionic conductivity (above 10{sup −4} S cm{sup −1}). Increasing the nanofiller content raises the ionic conductivity of the electrolyte by two orders of magnitude of which the optimum is 2.65 × 10{sup −4} S cm{sup −1} at 13.04 wt% ZrO{sub 2}-NC loading. Also, the Young’s modulus, an indicator of electrolyte’s mechanical stability, dramatically increased to 207 MPa upon loading 13.04 wt% ZrO{sub 2}-NC. Using UV–vis spectroscopy, the electrolytes with 13.04% ZrO{sub 2}-NC scanned from 200–800 nm wavelengths exhibited a maximum optical transmittance of 52.6% at 10 μm film thickness. The enhanced conductivity, high mechanical strength and reasonable optical transmittance shown by our composite polymer electrolyte make an excellent electrolyte for future energy saving smart windows such as electrochromic devices.

  9. Shape of isolated domains in lithium tantalate single crystals at elevated temperatures

    SciTech Connect

    Shur, V. Ya. Akhmatkhanov, A. R.; Baturin, I. S.; Chezganov, D. S.; Lobov, A. I.; Smirnov, M. M.

    2013-12-09

    The shape of isolated domains has been investigated in congruent lithium tantalate (CLT) single crystals at elevated temperatures and analyzed in terms of kinetic approach. The obtained temperature dependence of the growing domain shape in CLT including circular shape at temperatures above 190 °C has been attributed to increase of relative input of isotropic ionic conductivity. The observed nonstop wall motion and independent domain growth after merging in CLT as opposed to stoichiometric lithium tantalate have been attributed to difference in wall orientation. The computer simulation has confirmed applicability of the kinetic approach to the domain shape explanation.

  10. Growth and characterization of pure and semiorganic nonlinear optical Lithium Sulphate admixtured l-alanine crystal

    NASA Astrophysics Data System (ADS)

    Vela, T.; Selvarajan, P.; Freeda, T. H.; Balasubramanian, K.

    2013-04-01

    Lithium sulphate admixtured l-alanine (LSLA) salt was synthesized and the solubility of the commercially available l-alanine and the synthesized LSLA sample was determined in de-ionized water at various temperatures. In accordance with the solubility data, the saturated aqueous solutions of l-alanine and lithium admixtured l-alanine were prepared separately and the single crystals of the samples were grown by the solution method with a slow evaporation technique. Studying single x-ray diffraction shows that pure and LSLA crystal belong to the orthorhombic system with a non-centrosymmetric space group P212121. Using the powder x-ray diffraction study, the crystallinity of the grown crystals is confirmed and the diffraction peaks are indexed. The various functional groups present in the pure and LSLA crystal are elucidated from Fourier transform infrared spectroscopy study. UV-visible transmittance is recorded to study the optical transmittance range for the grown crystals. The powder second harmonic generation test confirms the nonlinear optical property of the grown crystals. From the microhardness test, the hardness of the grown crystals is estimated. The dielectric behaviour, such as the dielectric constant and the loss of the sample, are measured as a function of temperature and frequency. The ac conductivity of the grown crystals is also studied and the activation energy is calculated.

  11. Lithium

    MedlinePlus

    ... bipolar disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Lithium ... Lithium is also sometimes used to treat depression, schizophrenia (a mental ... emotions), disorders of impulse control (inability to resist the urge ...

  12. Structure and properties of quartz crystals grown from fluoride solutions: I. The morphology of basal pinacoid habit

    SciTech Connect

    Chuvyrov, A. N.; Mazitov, R. M.

    2008-09-15

    The mechanism of growth of quartz crystals from fluoride media has been investigated. It is shown by different independent methods (selective etching, X-ray diffraction analysis, optical microscopy) that the faceted forms of autonomous growth regions (trigonal pyramids formed on nonsingular crystal faces) are unstable and degenerate during growth. This degeneracy is accompanied by torsion deformation of autonomous growth regions and, as a result, formation of a series of hollow helical channels at boundaries of autonomous growth regions, whose axes make an angle of {approx}16{sup o} with the OZ axis, and their projections on the XOY plane are directed along the +X axes.

  13. Change in the structural imperfection of lithium niobate crystals doped with zinc

    SciTech Connect

    Litvinova, V. A. Litvinova, M. N.

    2015-01-15

    The changes in the degree of structural imperfection of lithium niobate (LiNbO{sub 3}) single crystals with an increase in the Li content and doping with zinc (to 1 wt %) have been investigated by the nonlinear optics methods and Raman spectroscopy. The conversion of broadband IR radiation in LiNbO{sub 3} crystals under noncritical (90°) phase-matching condition with vector interactions implemented is investigated. It is shown that the conversion efficiency, spectral width, and the position of maximum in the converted radiation spectrum depend on the ratio R = Li/Nb in LiNbO{sub 3} crystal and the impurity concentration.

  14. Growth and characterization of new semiorganic nonlinear optical and piezoelectric lithium sulfate monohydrate oxalate single crystals

    SciTech Connect

    Yadav, Harsh; Sinha, Nidhi; Kumar, Binay

    2015-04-15

    Highlights: • A new semiorganic single crystal of LSO grown by slow evaporation technique. • Morphological studies of the LSO crystal deduced by BFDH law. • In the UV–vis spectrum wide transparent region and large band gap were found. • SHG is equal to KDP crystal and d{sub 33} was found to be equal to 6pC/N. • Grown crystal belongs to softer category. - Abstract: New semiorganic crystal of lithium sulfate monohydrate oxalate (LSO) for nonlinear application was synthesized by controlled slow evaporation method. The growth rate of various planes of the grown crystal was estimated by morphological study. Single crystal XRD analysis confirmed that the crystal belongs to triclinic lattice with space group P1. High transparency (∼95%) with large band gap (4.57 eV) was analyzed by UV–vis studies. FTIR and Raman spectroscopy were used to identify various functional groups present in the LSO crystal. SHG efficiency was found to be equal to the KDP crystal. Thermal stability (up to 117.54 °C) and melting point (242 °C) of the crystal were studied by TG-DTA. In dielectric measurements, the value of dielectric constant decreases with increase in frequency. Hardness studies confirmed soft nature of crystals. The piezoelectric coefficient was found to be 6pC/N along [0 0 1].

  15. Ultrathin two-dimensional atomic crystals as stable interfacial layer for improvement of lithium metal anode.

    PubMed

    Yan, Kai; Lee, Hyun-Wook; Gao, Teng; Zheng, Guangyuan; Yao, Hongbin; Wang, Haotian; Lu, Zhenda; Zhou, Yu; Liang, Zheng; Liu, Zhongfan; Chu, Steven; Cui, Yi

    2014-10-08

    Stable cycling of lithium metal anode is challenging due to the dendritic lithium formation and high chemical reactivity of lithium with electrolyte and nearly all the materials. Here, we demonstrate a promising novel electrode design by growing two-dimensional (2D) atomic crystal layers including hexagonal boron nitride (h-BN) and graphene directly on Cu metal current collectors. Lithium ions were able to penetrate through the point and line defects of the 2D layers during the electrochemical deposition, leading to sandwiched lithium metal between ultrathin 2D layers and Cu. The 2D layers afford an excellent interfacial protection of Li metal due to their remarkable chemical stability as well as mechanical strength and flexibility, resulting from the strong intralayer bonds and ultrathin thickness. Smooth Li metal deposition without dendritic and mossy Li formation was realized. We showed stable cycling over 50 cycles with Coulombic efficiency ∼97% in organic carbonate electrolyte with current density and areal capacity up to the practical value of 2.0 mA/cm(2)and 5.0 mAh/cm(2), respectively, which is a significant improvement over the unprotected electrodes in the same electrolyte.

  16. Identification of electron and hole traps in lithium tetraborate (Li{sub 2}B{sub 4}O{sub 7}) crystals: Oxygen vacancies and lithium vacancies

    SciTech Connect

    Swinney, M. W.; McClory, J. W.; Petrosky, J. C.; Yang Shan; Brant, A. T.; Halliburton, L. E.; Adamiv, V. T.; Burak, Ya. V.; Dowben, P. A.

    2010-06-15

    Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to identify and characterize electrons trapped by oxygen vacancies and holes trapped by lithium vacancies in lithium tetraborate (Li{sub 2}B{sub 4}O{sub 7}) crystals. Our study includes a crystal with the natural abundances of {sup 10}B and {sup 11}B and a crystal highly enriched with {sup 10}B. The as-grown crystals contain isolated oxygen vacancies, lithium vacancies, and copper impurities, all in nonparamagnetic charge states. During an irradiation at 77 K with 60 kV x-rays, doubly ionized oxygen vacancies trap electrons while singly ionized lithium vacancies and monovalent copper impurities trap holes. The vacancies return to their preirradiation charge states when the temperature of the sample is increased to approximately 90 K. Hyperfine interactions with {sup 10}B and {sup 11}B nuclei, observed between 13 and 40 K in the radiation-induced EPR and ENDOR spectra, provide models for the two vacancy-related defects. The electron trapped by an oxygen vacancy is localized primarily on only one of the two neighboring boron ions while the hole stabilized by a lithium vacancy is localized on a neighboring oxygen ion with nearly equal interactions with the two boron ions adjacent to the oxygen ion.

  17. Interdomain region in single-crystal lithium niobate bimorph actuators produced by light annealing

    SciTech Connect

    Kubasov, I. V. Timshina, M. S.; Kiselev, D. A.; Malinkovich, M. D.; Bykov, A. S.; Parkhomenko, Yu. N.

    2015-09-15

    The interdomain region of a bidomain strucrture formed in 127°-cut lithium niobate single crystals using light annealing has been studied by optical and scanning probe microscopies. A periodic subdomain structure on the 180° macrodomain wall is visualized by piezoresponse force microscopy. The piezoresponse signal (polarization) is shown to be a power-law function of the domain width with an exponent n = 0.53.

  18. Three Dimensional Positron Annihilation Momentum Spectroscopy of Lithium Tetraborate Crystals

    DTIC Science & Technology

    2013-03-21

    defect analysis and will complement other characterization methods such as X-ray fluorescence (XRF), cathodoluminescence, thermoluminescence , and...candidate for high-sensitivity thermoluminescence dosimetry applications. Figure 5 shows a diagram of the basic structural component of the crystal

  19. Pyroelectric field assisted ion migration induced by ultraviolet laser irradiation and its impact on ferroelectric domain inversion in lithium niobate crystals

    SciTech Connect

    Ying, C. Y. J.; Mailis, S.; Daniell, G. J.; Steigerwald, H.; Soergel, E.

    2013-08-28

    The impact of UV laser irradiation on the distribution of lithium ions in ferroelectric lithium niobate single crystals has been numerically modelled. Strongly absorbed UV radiation at wavelengths of 244–305 nm produces steep temperature gradients which cause lithium ions to migrate and result in a local variation of the lithium concentration. In addition to the diffusion, here the pyroelectric effect is also taken into account which predicts a complex distribution of lithium concentration along the c-axis of the crystal: two separated lithium deficient regions on the surface and in depth. The modelling on the local lithium concentration and the subsequent variation of the coercive field are used to explain experimental results on the domain inversion of such UV treated lithium niobate crystals.

  20. Growth and characterization of lithium yttrium borate single crystals

    SciTech Connect

    Singh, A. K.; Singh, S. G.; Tyagi, M.; Desai, D. G.; Sen, Shashwati

    2014-04-24

    Single crystals of 0.1% Ce doped Li{sub 6}Y(BO{sub 3}){sub 3} have been grown using the Czochralski technique. The photoluminescence study of these crystals shows a broad emission at ∼ 420 nm corresponding to Ce{sub 3+} emission from 5d→4f energy levels. The decay profile of this emission shows a fast response of ∼ 28 ns which is highly desirable for detector applications.

  1. Electro-Spun Poly(vinylidene fluoride) Nanofiber Web as Separator for Lithium Ion Batteries: Effect of Pore Structure and Thickness.

    PubMed

    Lim, Seung-Gyu; Jo, Hye-Dam; Kim, Chan; Kim, Hee-Tak; Chang, Duck-Rye

    2016-01-01

    Electro-spun nanofiber web is highly attractive as a separator for lithium ion batteries because of its high electrical properties. In moving toward wider battery applications of the nanofiber separators, a deeper understanding on the structure and property relationship is highly meaningful. In this regard, we prepared electro-spun poly(vinylidene fluoride) (PVdF) webs with various thicknesses (10.5~100 µm) and investigated their structures and electrochemical performances. As the thickness of the web is decreased, a decrease of porosity and an increase of pore size are resulted in. For the 10.5 µm-thick separator, a minor short-circuit was detected, stressing the importance of reducing pore-size on prevention of short-circuit. However, above the thickness of 21 µm, well-connected, submicron-sized pores are generated, and, with lowering the separator thickness, discharge capacity and rate capability are enhanced owing to the lowered area-specific resistance.

  2. XRD, TEM, IR, Raman and NMR Spectroscopy of In Situ Crystallization of Lithium Disilicate Glass

    NASA Technical Reports Server (NTRS)

    Fuss, T.; Mogus-Milankovic, A.; Ray, C. S.; Lesher, C. E.; Youngman, R.; Day, D. E.

    2006-01-01

    The structure of a Li2O-2SiO2 (LS2) glass was investigated as a function of pressure and temperature up to 6 GPa and 750 C respectively, using XRD, TEM, IR, Raman and NMR spectroscopy. Glass densified at 6 GPa has an average Si-O-Si bond angle approx.7deg lower than that found in glass processed at 4.5 GPa. At 4.5 GPa, lithium disilicate crystallizes from the glass, while at 6 GPa a new high pressure form of lithium metasilicate crystallizes. The new phase, while having lithium metasilicate crystal symmetry, contains at least 4 different Si sites. NMR results for 6 GPa sample indicate the presence of Q4 species with (Q(sup 4))Si-O-Si(Q(sup 4)) bond angles of approx.157deg. This is the first reported occurrence of Q(sup 4) species with such large bond angles in alumina free alkali silicate glass. No five- or six- coordinated Si are found.

  3. Decomposition of the fluoroethylene carbonate additive and the glue effect of lithium fluoride products for the solid electrolyte interphase: an ab initio study.

    PubMed

    Okuno, Yukihiro; Ushirogata, Keisuke; Sodeyama, Keitaro; Tateyama, Yoshitaka

    2016-03-28

    Additives in the electrolyte solution of lithium-ion batteries (LIBs) have a large impact on the performance of the solid electrolyte interphase (SEI) that forms on the anode and is a key to the stability and durability of LIBs. We theoretically investigated effects of fluoroethylene carbonate (FEC), a representative additive, that has recently attracted considerable attention for the enhancement of cycling stability of silicon electrodes and the improvement of reversibility of sodium-ion batteries. First, we intensively examined the reductive decompositions by ring-opening, hydrogen fluoride (HF) elimination to form a vinylene carbonate (VC) additive and intermolecular chemical reactions of FEC in the ethylene carbonate (EC) electrolyte, by using density functional theory (DFT) based molecular dynamics and the blue-moon ensemble technique for the free energy profile. The results show that the most plausible product of the FEC reductive decomposition is lithium fluoride (LiF), and that the reactivity of FEC to anion radicals is found to be inert compared to the VC additive. We also investigated the effects of the generated LiF on the SEI by using two model systems; (1) LiF molecules distributed in a model aggregate of organic SEI film components (SFCs) and (2) a LiF aggregate interfaced with the SFC aggregate. DFT calculations of the former system show that F atoms form strong bindings with the Li atoms of multiple organic SFC molecules and play as a joint connecting them. In the latter interface system, the LiF aggregate adsorbs the organic SFCs through the F-Li bindings. These results suggest that LiF moieties play the role of glue in the organic SFC within the SEI film. We also examined the interface structure between a LiF aggregate and a lithiated silicon anode, and found that they are strongly bound. This strong binding is likely to be related to the effectiveness of the FEC additive in the electrolyte for the silicon anode.

  4. Micro-buried spiral zone plate in a lithium niobate crystal

    NASA Astrophysics Data System (ADS)

    Tian, Zhen-Nan; Hua, Jian-Guan; Hao, Juan; Yu, Yan-Hao; Chen, Qi-Dai; Sun, Hong-Bo

    2017-01-01

    We present a micro-buried spiral zone plate (MBSZP) in the lithium niobate crystal fabricated with femtosecond laser direct writing technology. The microstructures of the MBSZP are buried under the surface of the crystal, which ensures the stability of the optical performance in various refractive index environments. The optical performances of imaging and focusing capabilities were demonstrated. In addition, the experiment showed good agreement with simulation results based on the optical wave propagation method. This novel optical element will have important applications in multistate information encoding, optical manipulation, quantum communication, and computation, especially in high integration, contact coupling, and variable refractive index environments.

  5. One-Step Synthesis of Titanium Oxyhydroxy-Fluoride Rods and Research on the Electrochemical Performance for Lithium-ion Batteries and Sodium-ion Batteries.

    PubMed

    Li, Biao; Gao, Zhan; Wang, Dake; Hao, Qiaoyan; Wang, Yan; Wang, Yongkun; Tang, Kaibin

    2015-12-01

    Titanium oxyhydroxy-fluoride, TiO0.9(OH)0.9F1.2 · 0.59H2O rods with a hexagonal tungsten bronze (HTB) structure, was synthesized via a facile one-step solvothermal method. The structure, morphology, and component of the products were characterized by X-ray powder diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), inductively coupled plasma optical emission spectroscopy (ICP-OES), ion chromatograph, energy-dispersive X-ray (EDX) analyses, and so on. Different rod morphologies which ranged from nanoscale to submicron scale were simply obtained by adjusting reaction conditions. With one-dimension channels for Li/Na intercalation/de-intercalation, the electrochemical performance of titanium oxyhydroxy-fluoride for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) was also studied. Electrochemical tests revealed that, for LIBs, titanium oxyhydroxy-fluoride exhibited a stabilized reversible capacity of 200 mAh g(-1) at 25 mA g(-1) up to 120 cycles in the electrode potential range of 3.0-1.2 V and 140 mAh g(-1) at 250 mA g(-1) up to 500 cycles, especially; for SIBs, a high capacity of 100 mAh g(-1) was maintained at 25 mA g(-1) after 115 cycles in the potential range of 2.9-0.5 V.

  6. Single crystal growth by gel technique and characterization of lithium hydrogen tartrate

    NASA Astrophysics Data System (ADS)

    Ahmad, Nazir; Ahmad, M. M.; Kotru, P. N.

    2015-02-01

    Single crystal growth of lithium hydrogen tartrate by gel encapsulation technique is reported. Dependence of crystal count on gel density, gel pH, reactant concentration and temperature are studied and the optimum conditions for these crystals are worked out. The stoichiometric composition of the grown crystals is determined using EDAX/AES and CH analysis. The grown crystals are characterized by X-ray diffraction, FTIR and Uv-Visible spectroscopy. It is established that crystal falls under orthorhombic system and space group P222 with the cell parameters as: a=10.971 Å, b=13.125 Å and c=5.101 Å; α=90.5o, β=γ=90°. The morphology of the crystals as revealed by SEM is illustrated. Crystallite size, micro strain, dislocation density and distortion parameters are calculated from the powder XRD results of the crystal. UV-vis spectroscopy shows indirect allowed transition with an optical band gap of~4.83 eV. The crystals are also shown to have high transmittance in the entire visible region. Dependence of dielectric constant, dielectric loss and conductivity on frequency of the applied ac field is analyzed. The frequency-dependent real part of the complex ac conductivity is found to follow the universal dielectric response: σac (ω)~ωs. The trend in the variation of frequency exponent with frequency corroborates the fact that correlated barrier hopping is the dominant charge-transport mechanism in the present system.

  7. Poly(vinylidene fluoride)/SiO2 composite membranes prepared by electrospinning and their excellent properties for nonwoven separators for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Ma, Xilan; Cao, Chuanbao; Li, Jili; Zhu, Youqi

    2014-04-01

    PVdF/SiO2 composite nonwoven membranes exhibiting high safety (thermal stability), high ionic conductivity and excellent electrochemical performances are firstly prepared by electrospinning poly(vinylidene fluoride) (PVdF) homopolymer and silicon dioxide (SiO2) sol synchronously for the separators of lithium-ion batteries (LIBs). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and hot oven tests show that the PVdF/SiO2 composite nonwoven membranes are thermally stable at a high temperature of 400 °C while the commercial Celgard 2400 PP membrane exhibits great shrinkage at 130 °C, indicating a superior thermal stability of PVdF/SiO2 composite nonwoven membranes than that of Celgard membrane. Moreover, the composite membrane exhibits fairly high ionic conductivity (7.47 × 10-3 S cm-1) that significantly improves the performance of LIBs. The PVdF/SiO2 composite membranes are also evaluated to have higher level of porosity (75-85%) and electrolyte uptake (571-646 wt%), lower interfacial resistance compared to the Celgard separator. The lithium-ion cell (using LiFePO4 cathode) assembled with the composite membrane exhibits more stable cycle performance, higher discharge capacity (159 mAh g-1) and excellent capacity retention which proves that they are promising candidates for separators of high performance rechargeable LIBs.

  8. Poly(vinylidene fluoride) (PVDF) Binder Degradation in Li-O2 Batteries: A Consideration for the Characterization of Lithium Superoxide.

    PubMed

    Papp, Joseph K; Forster, Jason D; Burke, Colin M; Kim, Hyo Won; Luntz, Alan C; Shelby, Robert M; Urban, Jeffrey J; McCloskey, Bryan D

    2017-02-27

    We show that a common Li-O2 battery cathode binder, poly(vinylidene fluoride) (PVDF), degrades in the presence of reduced oxygen species during Li-O2 discharge when adventitious impurities are present. This degradation process forms products that exhibit Raman shifts (∼1133 and 1525 cm(-1)) nearly identical to those reported to belong to lithium superoxide (LiO2), complicating the identification of LiO2 in Li-O2 batteries. We show that these peaks are not observed when characterizing extracted discharged cathodes that employ poly(tetrafluoroethylene) (PTFE) as a binder, even when used to bind iridium-decorated reduced graphene oxide (Ir-rGO)-based cathodes similar to those that reportedly stabilize bulk LiO2 formation. We confirm that for all extracted discharged cathodes on which the 1133 and 1525 cm(-1) Raman shifts are observed, only a 2.0 e(-)/O2 process is identified during the discharge, and lithium peroxide (Li2O2) is predominantly formed (along with typical parasitic side product formation). Our results strongly suggest that bulk, stable LiO2 formation via the 1 e(-)/O2 process is not an active discharge reaction in Li-O2 batteries.

  9. Closely packed x-poly(ethylene glycol diacrylate) coated polyetherimide/poly(vinylidene fluoride) fiber separators for lithium ion batteries with enhanced thermostability and improved electrolyte wettability

    NASA Astrophysics Data System (ADS)

    Zhai, Yunyun; Xiao, Ke; Yu, Jianyong; Ding, Bin

    2016-09-01

    The x-polyethylene glycol diacrylate (x-PEGDA) coated polyetherimide/polyvinylidene fluoride (PEI/PVdF) membranes are obtained by the facile combination of dip-coating and free radical polymerization of PEGDA on the electrospun PEI/PVdF fiber membranes. Successful cross-linking of PEGDA increases the average fibers diameter from 553 to 817 nm and reduces the packing density, which not only increases the tensile strength of x-PEGDA coated PEI/PVdF membranes, but also decreases the average pore diameter. Besides, the x-PEGDA coated PEI/PVdF membranes are endowed with good wettability, high electrolyte uptake, high ionic conductivity and improved electrochemical stability window because of the good affinity of PEI and PEGDA with liquid electrolyte. Benefiting from the synergetic effect of PEI and PVdF, the x-PEGDA coated PEI/PVdF membranes exhibit excellent thermal stability and nonflammability, which are beneficial for enhancing the safety of lithium ion batteries. More importantly, the x-PEGDA coated PEI/PVdF membranes based Li/LiFePO4 cell exhibits comparable cycling stability with capacity retention of 95.9% after 70 cycles and better rate capability compared with the Celgard membrane based cell. The results clearly demonstrate that the x-PEGDA coated PEI/PVdF membranes are the promising separator candidate with improved wettability and safety for next-generation lithium ion batteries.

  10. Kagomé lattices as cathode: Effect of particle size and fluoride substitution on electrochemical lithium insertion in sodium- and ammonium Jarosites

    NASA Astrophysics Data System (ADS)

    Sandineni, Prashanth; Yaghoobnejad Asl, Hooman; Choudhury, Amitava

    2016-10-01

    Highly crystalline sodium and ammonium Jarosites, NaFe3(SO4)2(OH)6 and NH4Fe3(SO4)2(OH)6, have been synthesized employing hydrothermal synthesis routes. The structures consist of anionic layers of vertex-sharing FeO6 octahedra and SO4 tetrahedral units with interlayer space occupied by Na and ammonium ions, respectively. The corner-sharing FeO6 octahedral units form six and three rings similar to hexagonal tungsten bronze sheets also known as kagomé lattice. These sodium and ammonium Jarosites are thermally stable up to 400 °C and undergo facile electrochemical lithium insertion through the reduction of Fe3+ to Fe2+. Galvanostatic charge-discharge indicates that up to 2.25 and 2 lithium ions per formula unit can be inserted at an average voltage of 2.49 and 2.26 V to the sodium and the ammonium Jarosites, respectively, under slow discharge rate of C/50. The cycle-life and experimental achievable capacity show strong dependence on particle sizes and synthesis conditions. A small amount of fluoride substitution improves both achievable capacity and average voltage.

  11. Origin of UV-induced poling inhibition in lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Steigerwald, H.; Lilienblum, M.; von Cube, F.; Ying, Y. J.; Eason, R. W.; Mailis, S.; Sturman, B.; Soergel, E.; Buse, K.

    2010-12-01

    Short-term exposure of the +z face of LiNbO3 crystals to focused UV laser light leads to persistent inhibition of ferroelectric domain reversal at the irradiated area, a phenomenon referred to as “poling inhibition.” Different types of crystals (stoichiometric, congruent, or Mg-doped ones) are exposed, creating the so-called “latent state” and domain growth during subsequent electric-field poling is visualized. The latent state is robust against thermal annealing up to 250°C and uniform illumination. With the tip of a scanning force microscope the coercive field is mapped, showing not only the expected resistance against domain reversal in the UV-irradiated region but also easier poling adjacent to the UV-irradiated section. These results and theoretical estimates point to the following mechanism of poling inhibition: the UV light-induced heating results in a local reduction of the lithium concentration, via thermodiffusion. The required charge compensation is provided by UV-excited free electrons/holes. After cooling, the lithium ions become immobile, and the reduced lithium concentration causes a strong local increase in the coercive field in the exposed area, while the increased Li concentration next to this area reduces the coercive field.

  12. Effect of lithium chloride on spectral, optical, thermal and mechanical behaviour of bis thiourea zinc acetate crystals.

    PubMed

    Ruby Nirmala, L; Thomas Joseph Prakash, J

    2012-11-01

    Single crystals of pure bis thiourea zinc acetate (BTZA) and lithium chloride (LiCl) doped BTZA have been synthesized and grown successfully from aqueous solutions by slow evaporation technique. The single crystals thus grown were characterized by different techniques such as single crystal XRD, AAS, FT-IR, UV-Vis, TG/DTA and SHG test. The single crystal XRD study proved that the dopant has not changed the structure of the parent crystal. The AAS study confirmed the presence of lithium in the doped crystal. The FTIR study ascertained the metal coordination of lithium chloride doped BTZA through thiourea. The optical behavior of the doped crystal has been examined by UV spectral analysis. Thermal studies TGA & DTA of the doped crystal have been investigated and found that the doped crystal is thermally more stable than the pure crystal. The SHG test using Nd: YAG Laser confirmed the NLO activity of the pure and doped crystal. The obtained results are presented and discussed.

  13. Growth and properties of Lithium Salicylate single crystals

    SciTech Connect

    Zaitseva, N; Newby, J; Hull, G; Saw, C; Carman, L; Cherepy, N; Payne, S

    2009-02-13

    An attractive feature of {sup 6}Li containing fluorescence materials that determines their potential application in radiation detection is the capture reaction with slow ({approx}< 100 keV) neutrons: {sup 6}Li + n = {sup 4}He + {sup 3}H + 4.8MeV. The use of {sup 6}Li-salicylate (LiSal, LiC{sub 6}H{sub 5}O{sub 3}) for thermal neutron detection was previously studied in liquid and polycrystalline scintillators. The studies showed that both liquid and polycrystalline LiSal scintillators could be utilized in pulse shape discrimination (PSD) techniques that enable separation of neutrons from the background gamma radiation. However, it was found that the efficiency of neutron detection using LiSal in liquid solutions was severely limited by its low solubility in commonly used organic solvents like, for example, toluene or xylene. Better results were obtained with neutron detectors containing the compound in its crystalline form, such as pressed pellets, or microscopic-scale (7-14 micron) crystals dispersed in various media. The expectation drown from these studies was that further improvement of pulse height, PSD, and efficiency characteristics could be reached with larger and more transparent LiSal crystals, growth of which has not been reported so far. In this paper, we present the first results on growth and characterization of relatively large, a cm-scale size, single crystals of LiSal with good optical quality. The crystals were grown both from aqueous and anhydrous (methanol) media, mainly for neutron detection studies. However, the results on growth and structural characterization may be interesting for other fields where LiSal, together with other alkali metal salicylates, is used for biological, medical, and chemical (as catalyst) applications.

  14. Selective crystallization with preferred lithium-ion storage capability of inorganic materials

    PubMed Central

    2012-01-01

    Lithium-ion batteries are supposed to be a key method to make a more efficient use of energy. In the past decade, nanostructured electrode materials have been extensively studied and have presented the opportunity to achieve superior performance for the next-generation batteries which require higher energy and power densities and longer cycle life. In this article, we reviewed recent research activities on selective crystallization of inorganic materials into nanostructured electrodes for lithium-ion batteries and discuss how selective crystallization can improve the electrode performance of materials; for example, selective exposure of surfaces normal to the ionic diffusion paths can greatly enhance the ion conductivity of insertion-type materials; crystallization of alloying-type materials into nanowire arrays has proven to be a good solution to the electrode pulverization problem; and constructing conversion-type materials into hollow structures is an effective approach to buffer the volume variation during cycling. The major goal of this review is to demonstrate the importance of crystallization in energy storage applications. PMID:22353373

  15. Structural, optical and dielectric studies of novel non-linear Bisglycine Lithium Nitrate piezoelectric single crystal

    NASA Astrophysics Data System (ADS)

    Dalal, Jyoti; Sinha, Nidhi; Kumar, Binay

    2014-11-01

    The novel non-linear semiorganic Bisglycine Lithium Nitrate (BGLiN) single crystals were grown by slow evaporation technique. The structural analysis revealed that it belongs to non-centrosymmetric orthorhombic structure. The presence of various functional groups in the grown crystal was confirmed by FTIR and Raman analysis. Surface morphology of the grown crystal was studied by scanning electron microscopy. The optical studies show that crystal has good transmittance (more than 80%) in the entire visible region and a wide band gap (5.17 eV). The optical constants such as extinction coefficient (K), the reflectance (R) and refractive index (n) as a function of photon energy were calculated from the optical measurements. With the help of these optical constants the electric susceptibility (χc) and both the real (εr) and imaginary (εi) parts of the dielectric constants were also calculated which are required to develop optoelectronic devices. In photoluminescence studies, a broad emission band centered at 404 nm was found in addition to a small band at 352 nm. A broad transition (from 29 to 33 °C) was observed with low dielectric constant value. A high piezoelectric charge coefficient (d33) of 14 pC/N was measured at room temperature which implies its usefulness for various sensor applications. The second harmonic generation efficiency of crystal was found to be 1.5 times to that of KDP. From thermo gravimetric analysis and differential thermal analysis, thermal stability and melting point (246 °C) were investigated. The dielectric behavior, optical characterization, piezoelectric behavior and the non-linear optical properties of the Bisglycine Lithium Nitrate single crystals were reported for the first time which established the usefulness of these crystals for various piezo- and opto-electronics applications.

  16. The photorefractive characteristics of bismuth-oxide doped lithium niobate crystals

    SciTech Connect

    Zheng, Dahuai; Yao, Jiaying; Kong, Yongfa; Liu, Shiguo; Zhang, Ling; Chen, Shaolin; Xu, Jingjun

    2015-01-15

    Bismuth-doped lithium niobate (LN:Bi) crystals were grown by Czochralski method and their optical damage resistance, photorefraction, absorption spectra, and defect energy levels were investigated. The experimental results indicate that the photorefractive properties of LN:Bi were enhanced as compared with congruent one, the photorefractive response time was greatly shortened, the photorefractive sensitivity was increased, and the diffraction efficiency of near-stoichiometric LN:Bi (SLN:Bi) reached 31.72% and 49.08% at 532 nm and 488 nm laser, respectively (light intensity of 400 mW/cm{sup 2}). An absorption peak at about 350 nm was observed in the absorption spectrum of LN:Bi. And the defect energy levels simulation indicates new defect levels appear in the forbidden gap of LN:Bi crystals. Therefore bismuth can act as photorefractive centers in LN crystals.

  17. Single crystal growth from separated educts and its application to lithium transition-metal oxides

    NASA Astrophysics Data System (ADS)

    Freund, F.; Williams, S. C.; Johnson, R. D.; Coldea, R.; Gegenwart, P.; Jesche, A.

    2016-10-01

    Thorough mixing of the starting materials is the first step of a crystal growth procedure. This holds true for almost any standard technique, whereas the intentional separation of educts is considered to be restricted to a very limited number of cases. Here we show that single crystals of α-Li2IrO3 can be grown from separated educts in an open crucible in air. Elemental lithium and iridium are oxidized and transported over a distance of typically one centimeter. In contrast to classical vapor transport, the process is essentially isothermal and a temperature gradient of minor importance. Single crystals grow from an exposed condensation point placed in between the educts. The method has also been applied to the growth of Li2RuO3, Li2PtO3 and β-Li2IrO3. A successful use of this simple and low cost technique for various other materials is anticipated.

  18. Single crystal growth from separated educts and its application to lithium transition-metal oxides

    PubMed Central

    Freund, F.; Williams, S. C.; Johnson, R. D.; Coldea, R.; Gegenwart, P.; Jesche, A.

    2016-01-01

    Thorough mixing of the starting materials is the first step of a crystal growth procedure. This holds true for almost any standard technique, whereas the intentional separation of educts is considered to be restricted to a very limited number of cases. Here we show that single crystals of α-Li2IrO3 can be grown from separated educts in an open crucible in air. Elemental lithium and iridium are oxidized and transported over a distance of typically one centimeter. In contrast to classical vapor transport, the process is essentially isothermal and a temperature gradient of minor importance. Single crystals grow from an exposed condensation point placed in between the educts. The method has also been applied to the growth of Li2RuO3, Li2PtO3 and β-Li2IrO3. A successful use of this simple and low cost technique for various other materials is anticipated. PMID:27748402

  19. Low temperature dc electrical conduction in reduced lithium niobate single crystals

    NASA Astrophysics Data System (ADS)

    Dhar, Ajay; Singh, Nidhi; Singh, Rajiv K.; Singh, Ramadhar

    2013-01-01

    The direct current (dc) electrical conductivity of unreduced and reduced lithium niobate (LiNbO3) single crystals has been measured at room temperature (˜300 K). The dc conductivity and activation energy show strong dependence on the degree of oxygen reduction in LiNbO3 single crystals. The dc conductivity exhibits a peak as a function of increasing degree of oxygen reduction. These results have been analysed assuming small polaron hopping conduction between Nb4+ and Nb5+ ion sites. The temperature dependence of dc conductivity of reduced LiNbO3 single crystal, exhibiting the highest dc conductivity, has been examined in the temperature range 77-373 K. The observed dc conductivity data has been analyzed and explained in terms of Mott’s variable range hopping (VRH) conduction model involving a single phonon hopping process.

  20. Strong tendency of homeotropic alignment and anisotropic lithium ion conductivity of sulfonate functionalized zwitterionic imidazolium ionic liquid crystals.

    PubMed

    Rondla, Rohini; Lin, Joseph C Y; Yang, C T; Lin, Ivan J B

    2013-09-17

    Here, we report the first attempt to investigate the liquid crystal (LC) behavior of SO3(-) functionalized imidazolium zwitterionic (SO3(-)ImZI) salts, which display homeotropic alignment on a glass slide without the aid of any aligning approach. Doping lithium salt to ImZI salts lowers the melting temperatures and raises the clearing temperatures substantially to form room temperature ImZILCs. Excellent anisotropic lithium ion conductivity is achieved; which is strengthened by their tendency for homeotropic alignment.

  1. Solid sampling determination of magnesium in lithium niobate crystals by graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Dravecz, Gabriella; Laczai, Nikoletta; Hajdara, Ivett; Bencs, László

    2016-12-01

    The vaporization/atomization processes of Mg in high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS) were investigated by evaporating solid (powder) samples of lithium niobate (LiNbO3) optical single crystals doped with various amounts of Mg in a transversally heated graphite atomizer (THGA). Optimal analytical conditions were attained by using the Mg I 215.4353 nm secondary spectral line. An optimal pyrolysis temperature of 1500 °C was found for Mg, while the compromise atomization temperature in THGAs (2400 °C) was applied for analyte vaporization. The calibration was performed against solid (powered) lithium niobate crystal standards. The standards were prepared with exactly known Mg content via solid state fusion of the oxide components of the matrix and analyte. The correlation coefficient (R value) of the linear calibration was not worse than 0.9992. The calibration curves were linear in the dopant concentration range of interest (0.74-7.25 mg/g Mg), when dosing 3-10 mg of the powder samples into the graphite sample insertion boats. The Mg content of the studied 19 samples was in the range of 1.69-4.13 mg/g. The precision of the method was better than 6.3%. The accuracy of the results was verified by means of flame atomic absorption spectrometry with solution sample introduction after digestion of several crystal samples.

  2. Photo-written three-dimensional optical circuits in iron doped lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Zhao, Jianlin; Xu, Honglai; Ma, Yanghua; Yang, Dexing

    2006-02-01

    We present our experimental results on fabricating optical waveguides by laser micromachining, structure-light illuminating, and optical spatial dark solitons in iron doped lithium niobate (LiNbO 3:Fe) crystals. After that we propose a novel approach to fabricate three-dimensional (3-D) optical circuits in LiNbO 3 crystals by combining the three light-induction techniques listed above. By employing laser micromachining, a curved and a Y-branches waveguides are successfully fabricated. With binary and SLM-prepared optical masks, Y-branches and gradient planar waveguides are experimentally demonstrated. By utilizing one-dimensional (1-D) optical spatial dark solitons, planar, Y-branches, and square channel waveguides are formed. The results show that each of the three methods can be employed to write optical waveguides in LiNbO3 crystals. By combing the three methods, 3-D light circuits can be created in 45 °-cut bulk crystals by several procedures. Initially, a quasi-planar optical circuit is created in a thin layer of the crystal by structure-light illuminating with an optical mask. Then, a planar circuit is generated by utilizing a 1-D dark soltion. And then, form multi-layer planar circuits are formed by altering the positions of the crystal or writing beam. Finally, laser micromachining is used to link the different layers to form a 3-D light circuit. Furthermore, functional 3-D integrated optical system may be implemented by using the proposed approach.

  3. Refractive index changes in lithium niobate crystals by high-energy particle radiation

    SciTech Connect

    Peithmann, Konrad; Zamani-Meymian, Mohammad-Reza; Haaks, Matz; Maier, Karl; Andreas, Birk; Breunig, Ingo

    2006-10-15

    Irradiation of lithium niobate crystals with 41 MeV {sup 3}He ions causes strong changes of the ordinary and extraordinary refractive indexes. We present a detailed study of this effect. Small fluence of irradiation already yields refractive index changes about 5x10{sup -4}; the highest values reach 3x10{sup -3}. These index modulations are stable up to 100 degree sign C and can be erased thermally, for which temperatures up to 500 degree sign C are required. A direct correlation between the refractive index changes and the produced lattice vacancies is found.

  4. EPR and optical absorption study of Cu2+ doped lithium sulphate monohydrate (LSMH) single crystals

    NASA Astrophysics Data System (ADS)

    Sheela, K. Juliet; Krishnan, S. Radha; Shanmugam, V. M.; Subramanian, P.

    2016-05-01

    EPR study of Cu2+ doped NLO active Lithium Sulphate monohydrate (Li2SO4.H2O) single crystals were grown successfully by slow evaporation method at room temperature. The principal values of g and A tensors indicate existence of orthorhombic symmetry around the Cu2+ ion. From the direction cosines of g and A tensors, the locations of Cu2+ in the lattice have been identified as interstitial site. Optical absorption confirms the rhombic symmetry and ground state wave function of the Cu2+ ion in a lattice as dx2-y2.

  5. Mode analysis of photonic crystal L3 cavities in self-suspended lithium niobate membranes

    SciTech Connect

    Diziain, Séverine Geiss, Reinhard; Zilk, Matthias; Schrempel, Frank; Kley, Ernst-Bernhard; Pertsch, Thomas; Tünnermann, Andreas

    2013-12-16

    We report on a multimodal analysis of photonic crystal L3 cavities milled in lithium niobate free-standing membranes. The classical L3 cavity geometry is compared to an L3 cavity containing a second lattice superimposed on the primary one. Those two different geometries are investigated in terms of vertical radiation and quality (Q) factor for each mode of the cavities. Depending on the cavity geometry, some modes undergo an enhancement of their vertical radiation into small angles while other modes experience a higher Q factor. Experimental characterizations are corroborated by three-dimensional finite difference time domain simulations.

  6. Coadsorption of lithium and oxygen on W(1 1 2): nanosized facets versus single crystals.

    PubMed

    Suchorski, Y; Hupalo, M S

    2011-05-01

    Coadsorption of lithium and oxygen on a nanosized W-tip is studied using field ion appearance energy spectroscopy (FIAES). Binding energies of coadsorbed Li-adatoms are derived locally for chosen atomic sites on (1 1 2) facets for different oxygen and Li-coverages. Independently, the binding energies of Li-adatoms in coadsorbed Li/oxygen layers are determined for macroscopic W(1 1 2) single crystal samples from the adsorption isobars in adsorption-desorption equilibrium experiments and compared with the local nm-scale measurements. The comparison reveals a very good agreement of results obtained by two different methods on differing length scales.

  7. Isothermal Analysis of the Crystallization Kinetics in Lithium Disilicate Glass using Trans Temp Furnace

    NASA Technical Reports Server (NTRS)

    Fuss, T.; Ray, C. S.; Day, D. E.

    2006-01-01

    Crystallization kinetics for lithium disilicate, Li2O2SiO2, (LS2) glass has been studied extensively by nonisothermal methods, but only a few studies on the isothermal crystallization kinetics of LS2 are available. In the present research, isothermal crystallization experiments or the LS2 glass were conducted in a Trans Temp furnace between 600 and 635 C, and selected properties such as the activation energy for crystallization (E), crystal growth index or Avrami parameter (n), the concentration of quenched-in nuclei in the starting glass (Ni) and the crystal nucleation rate (I) were measured. The crystal nucleation rate (I) was measured at only one selected temperature of 452 C, at this time. This commercial furnace has a 13 cm long isothermal heating zone (+/- 1 C) that allows precise heat treatment of relatively large samples. By placing a thermocouple within approx. 2 mm of the sample, it was possible to detect the heat of crystallization in the form of an isothermal crystallization exotherm during isothermal heat treatment of the sample. The values of E (318 plus or minus 10 kJ/mol), n (3.6 plus or minus 0.l), and N(sub i) (1.6 x 10(exp l2) m(sup -3)) calculated by analyzing these isotherms using the standard Johnson-Mehl-Avrami (JMA) equation were reproducible and in agreement with the literature values. The value of I, 1.9 x 10(exp 10) m(sup -3) s(sup -1) at 452 C, is an order of magnitude higher than the reported value for LS2.

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

    PubMed

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

    2016-06-14

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    PubMed Central

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

    2016-01-01

    Long-term durability is a major obstacle limiting the widespread use of lithium-ion batteries in heavy-duty applications and others demanding extended lifetime. As one of the root causes of the degradation of battery performance, the electrode failure mechanisms are still unknown. In this paper, we reveal the fundamental fracture mechanisms of single-crystal silicon electrodes over extended lithiation/delithiation cycles, using electrochemical testing, microstructure characterization, fracture mechanics and finite element analysis. Anisotropic lithium invasion causes crack initiation perpendicular to the electrode surface, followed by growth through the electrode thickness. The low fracture energy of the lithiated/unlithiated silicon interface provides a weak microstructural path for crack deflection, accounting for the crack patterns and delamination observed after repeated cycling. On the basis of this physical understanding, we demonstrate how electrolyte additives can heal electrode cracks and provide strategies to enhance the fracture resistance in future lithium-ion batteries from surface chemical, electrochemical and material science perspectives. PMID:27297565

  11. Polymeric ionic liquid-plastic crystal composite electrolytes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Li, Xiaowei; Zhang, Zhengxi; Li, Sijian; Yang, Li; Hirano, Shin-ichi

    2016-03-01

    In this work, composite polymer electrolytes (CPEs), that is, 80%[(1-x)PIL-(x)SN]-20%LiTFSI, are successfully prepared by using a pyrrolidinium-based polymeric ionic liquid (P(DADMA)TFSI) as a polymer host, succinonitrile (SN) as a plastic crystal, and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a lithium salt. XRD and DSC measurements confirm that the as-obtained CPEs have amorphous structures. The 80%[50%PIL-50%SN]-20%LiTFSI (50% SN) electrolyte reveals a high room temperature ionic conductivity of 5.74 × 10-4 S cm-1, a wide electrochemical window of 5.5 V, as well as good mechanical strength with a Young's modulus of 4.9 MPa. Li/LiFePO4 cells assembled with the 50% SN electrolyte at 0.1C rate can deliver a discharge capacity of about 150 mAh g-1 at 25 °C, with excellent capacity retention. Furthermore, such cells are able to achieve stable discharge capacities of 131.8 and 121.2 mAh g-1 at 0.5C and 1.0C rate, respectively. The impressive findings demonstrate that the electrolyte system prepared in this work has great potential for application in lithium ion batteries.

  12. Resonance laser-plasma excitation of coherent terahertz phonons in the bulk of fluorine-bearing crystals under high-intensity femtosecond laser irradiation

    SciTech Connect

    Potemkin, F V; Mareev, E I; Khodakovskii, N G; Mikheev, P M

    2013-08-31

    The dynamics of coherent phonons in fluorine-containing crystals was investigated by pump-probe technique in the plasma production regime. Several phonon modes, whose frequencies are overtones of the 0.38-THz fundamental frequency, were simultaneously observed in a lithium fluoride crystal. Phonons with frequencies of 1 and 0.1 THz were discovered in a calcium fluoride crystal and coherent phonons with frequencies of 1 THz and 67 GHz were observed in a barium fluoride crystal. Furthermore, in the latter case the amplitudes of phonon mode oscillations were found to significantly increase 15 ps after laser irradiation. (interaction of laser radiation with matter)

  13. Fluoridated Water

    MedlinePlus

    ... Genetics Services Directory Cancer Prevention Overview Research Fluoridated Water On This Page What is fluoride, and where is it found? What is water fluoridation? When did water fluoridation begin in the ...

  14. Fluoridation Basics

    MedlinePlus

    ... Water Fluoridation Journal Articles for Community Water Fluoridation Water Fluoridation Basics Recommend on Facebook Tweet Share Compartir ... because of tooth decay. History of Fluoride in Water In the 1930s, scientists examined the relationship between ...

  15. Fluoride-modified electrical properties of lead borate glasses and electrochemically induced crystallization in the glassy state

    SciTech Connect

    M'Peko, Jean-Claude; Souza, Jose E. de; Rojas, Seila S.; Hernandes, Antonio C.

    2008-02-15

    Lead fluoroborate glasses were prepared by the melt-quenching technique and characterized in terms of (micro)structural and electrical properties. The study was conducted on as prepared as well as temperature- and/or electric field-treated glass samples. The results show that, in the as-prepared glassy-state materials, electrical conductivity improved with increasing the PbF{sub 2} glass content. This result involves both an increase of the fluoride charge carrier density and, especially, a decrease of the activation energy from a glass structure expansion improving charge carrier mobility. Moreover, for the electric field-treated glass samples, surface crystallization was observed even below the glass transition temperature. As previously proposed in literature, and shown here, the occurrence of this phenomenon arose from an electrochemically induced redox reaction at the electrodes, followed by crystallite nucleation. Once nucleated, growth of {beta}-PbF{sub 2} crystallites, with the indication of incorporating reduced lead ions (Pb{sup +}), was both (micro)structurally and electrically detectable and analyzed. The overall crystallization-associated features observed here adapt well with the floppy-rigid model that has been proposed to further complete the original continuous-random-network model by Zachariasen for closely addressing not only glasses' structure but also crystallization mechanism. Finally, the crystallization-modified kinetic picture of the glasses' electrical properties, through application of polarization/depolarization measurements originally combined with impedance spectroscopy, was extensively explored.

  16. Emission cross sections and energy extraction for the mid-infrared transitions of Er, Tm, and Ho in oxide and fluoride crystals

    SciTech Connect

    Chase, L.L.; Payne, S.A.; Smith, L.K.; Kway, W.L.; Krupke, W.F.

    1991-04-01

    Emission cross sections have been measured for the transitions between the two lowest spin orbit multiplets of Er, Tm, and Ho in several fluoride and oxide crystals. Properties affecting energy extraction efficiency are summarized and pulsed extraction performance is calculated for several of these quasi-three-level laser media. 4 refs., 9 figs.

  17. 5 d-4 f luminescence of Nd3+, Gd3+, Er3+, Tm3+, and Ho3+ ions in crystals of alkaline earth fluorides

    NASA Astrophysics Data System (ADS)

    Radzhabov, E. A.; Prosekina, E. A.

    2011-09-01

    The vacuum ultraviolet emission spectra of alkaline-earth fluoride (CaF2, SrF2, BaF2) crystals with rare earth impurity ions (Nd, Gd, Er, Tm, Ho) have been investigated. The main luminescence bands are described well by the transitions from the lowest excited 5 d state to different 4 f levels of rare earth ions.

  18. A graphene loading heterogeneous hydrated forms iron based fluoride nanocomposite as novel and high-capacity cathode material for lithium/sodium ion batteries

    NASA Astrophysics Data System (ADS)

    Shen, Yongqiang; Wang, Xianyou; Hu, Hai; Jiang, Miaoling; Yang, Xiukang; Shu, Hongbo

    2015-06-01

    A graphene loading heterogeneous hydrated forms iron based fluoride (abbreviated as FeF3·xH2O/G) nanocomposite is successfully designed and synthesized for the first time by a sol-gel method. It found that the FeF3·xH2O nanoparticles distribute randomly on the surface of the graphene, stacking together to form a nanocomposite with high specific surface and abundant mesporous structure. The FeF3·xH2O was consisted of FeF3·3H2O and FeF2.5·0.5H2O with pyrochlore phase structure and FeF3·0.33H2O with hexagonal-tungsten-bronze-type structure (HTB). The FeF3·xH2O/G was used as cathode materials of rechargeable lithium/sodium batteries, respectively. It has been found that it can deliver a large reversible capacity exceeding 200 mAh g-1 and excellent cyclic performance with a residual capacity of 183 mAh g-1 after 100 cycles at 0.2C and 149 mAh g-1 after 200 cycles at 1C, especially, an outstanding rate performance exceeding 130 mAh g-1 at 5C in the voltage range of 1.5-4.5 V for Li-ion batteries. Moreover, when FeF3·xH2O/G is used as cathode material of Na-ion batteries, it exhibits also a high reversible capacity of 101 mAh g-1 after 30 cycles in the voltage range of 1.0-4.0 V at 0.1C. Therefore, FeF3·xH2O/G will a promising cathode material for high-performance lithium/sodium ion batteries.

  19. Anomalous dielectric relaxation in lithium-potassium tantalate crystals

    NASA Astrophysics Data System (ADS)

    Doussineau, P.; Farssi, Y.; Frénois, C.; Levelut, A.; Toulouse, J.; Ziolkiewicz, S.

    1994-08-01

    In order to describe the unusual dielectric properties observed in Ki{1-χ}Li{χ}TaO3. crystals a new approchh is proposed. The dynamical Glauber theory, previously applied to spinglasses, is modifiéd by the introduction of the spectral distribution of the random interactions between the dipoles associated with the Li+ ions. Moreover, the dipole corrélations are taken into account by the Onsager réaction field. As a result, the calculated dielectric constant reproduces well the unusual features of the Argand diagrams and, in particular, their finite slope at low frequencies and infinite slope at high frequencies (strophoidal shape). The temperature dépendance of some parameters shows, however, the limits of a spin-glass type model in describing the collective behaviour of randomly distributed dipoles in a highly polarizable medium. Une nouvelle approche est présentée qui permet de décrire les propriétés diélectriques particulières de cristaux mixtes de Ki{1-χ}Li{χ}TaO3. Elle s'appuie sur la théorie dynamique de Glauber, déjà utilisée pour les verres de spins, et modifiée par l'introduction d'une distribution spectrale spécifique aux interactions aléatoires des dipôles électriques associés aux ions Li+. En outre, les corrélations entre dipôles sont prises en compte par le champ de réaction d'Onsager. II s'ensuit que la constante diélectrique complexe ainsi calculée reproduit fidèlement les particularités des diagrammes d'Argand, telles que la pente finie aux basses fréquences et la pente infinie aux hautes fréquences (forme strophoïdale). La dépendance en température de certains paramètres déterminés par le calcul montre les limites de l'analogie avec les verres de spins et met en évidence le rôle d'un réseau très polarisable dans le comportement collectif d'une assemblée de dipôles électriques.

  20. Realisation of an all solid state lithium battery using solid high temperature plastic crystal electrolytes exhibiting liquid like conductivity.

    PubMed

    Shekibi, Youssof; Rüther, Thomas; Huang, Junhua; Hollenkamp, Anthony F

    2012-04-07

    Replacement of volatile and combustible electrolytes in conventional lithium batteries is desirable for two reasons: safety concerns and increase in specific energy. In this work we consider the use of an ionic organic plastic crystal material (IOPC), N-ethyl-N-methylpyrrolidinium tetrafluoroborate, [C2mpyr][BF(4)], as a solid-state electrolyte for lithium battery applications. The effect of inclusion of 1 to 33 mol% lithium tetrafluoroborate, LiBF(4), into [C2mpyr][BF(4)] has been investigated over a wide temperature range by differential scanning calorimetry (DSC), impedance spectroscopy, cyclic voltammetry and cycling of full Li|LiFePO(4) batteries. The increases in ionic conductivity by orders of magnitude observed at higher temperature are most likely associated with an increase in Li ion mobility in the highest plastic phase. At concentrations >5 mol% LiBF(4) the ionic conductivity of these solid-state composites is comparable to the ionic conductivity of room temperature ionic liquids. Galvanostatic cycling of Li|Li symmetrical cells showed that the reversibility of the lithium metal redox reaction at the interface of this plastic crystal electrolyte is sufficient for lithium battery applications. For the first time we demonstrate an all solid state lithium battery incorporating solid electrolytes based on IOPC as opposed to conventional flammable organic solvents.

  1. Calcium fluoride window mounting

    NASA Astrophysics Data System (ADS)

    Berger, D. Douglas

    1982-10-01

    A technique has been developed for joining a large calcium fluoride crystal to a stainless-steel flange by means of a silver transition ring. The process involves both vacuum brazing using a copper-silver alloy and air brazing using silver chloride. This paper describes the procedure used in fabricating a high-vacuum leak-tight calcium fluoride window assembly.

  2. A Novel Coupled Resonator Photonic Crystal Design in Lithium Niobate for Electrooptic Applications

    DOE PAGES

    Ozturk, Birol; Yavuzcetin, Ozgur; Sridhar, Srinivas

    2015-01-01

    High-aspect-ratio photonic crystal air-hole fabrication on bulk Lithium Niobate (LN) substrates is extremely difficult due to its inherent resistance to etching, resulting in conical structures and high insertion losses. Here, we propose a novel coupled resonator photonic crystal (CRPC) design, combining a coupled resonator approach with that of Bragg gratings. CRPC design parameters were optimized by analytical calculations and FDTD simulations. CRPC structures with optimized parameters were fabricated and electrooptically tested on bulk LN annealed proton exchange waveguides. Low insertion loss and large electrooptic effect were observed with the fabricated devices, making the CRPC design a promising structure for electroopticmore » device applications.« less

  3. Crystallization, Microstructure, and Viscosity Evolutions in Lithium Aluminosilicate Glass-Ceramics

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Wheaton, Bryan; Geisinger, Karen; Credle, Allen; Wang, Jie

    2016-11-01

    Lithium aluminosilicate glass-ceramics have found widespread commercial success in areas such as consumer products, telescope mirrors, fireplace windows, etc. However, there is still much to learn regarding the fundamental mechanisms of crystallization, especially related to the evolution of viscosity as a function of the crystallization (ceramming) process. In this study, the impact of phase assemblage and microstructure on the viscosity was investigated using high temperature X-ray diffraction (HTXRD), beam bending viscometry (BBV), and transmission electron microscopy (TEM). Results from this study provide a first direct observation of viscosity evolution as a function of ceramming time and temperature. Sharp viscosity increases due to phase separation, nucleation and phase transformation are noticed through BBV measurement. A near-net shape ceramming can be achieved in TiO2-containing compositions by keeping the glass at a high viscosity (> 109 Pa.s) throughout the whole thermal treatment.

  4. A thermodynamic and crystal structure study of thermally aged lithium ion cells

    NASA Astrophysics Data System (ADS)

    Maher, Kenza; Yazami, Rachid

    2014-09-01

    Lithium ion batteries in the coin-cell form factor (2032) initially charged to 4.2 V at ambient temperature are stored at 60 °C and 70 °C for up to 8 weeks. The cells discharge capacity (Qd) and thermodynamic properties, including open-circuit potential (OCP), entropy (ΔS) and enthalpy (ΔH) are measured after each completed ageing week. Post-mortem analysis of aged anodes and cathodes is investigated by X-ray diffractometry (XRD) and Raman Scattering spectrometry (RS) in an attempt to correlate thermodynamic data to changes in the crystal structure characteristics. It is found that degradation of the electrode materials' crystal structure accounts for most of the observed changes in the cells' thermodynamics with well quantified and distinct contributions from anode and cathode.

  5. Local Lattice Structure and Dopant Occupancy of Doped Lithium Niobate Crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Zhigang; Xue, Dongfeng

    We present a systematic study of the local distortions produced upon doping metal ions to lithium niobate (LiNbO3, LN) single crystals. The impurity bond length can be predicted by a radial force constant model, when the dopant ions substitute for Li+ or Nb5+ ions in the LN crystallographic frame. From the viewpoint of constituent chemical bonds, the lattice energy can be described as the function of bond valence on the basis of Born-Haber cycle for the formation of an ionic oxide MmOn. The dopant occupancy in the LN matrix can be determined by comparing the deviation of its lattice energy in different locations at both Li+ and Nb5+ sites, on the basis of the bond length relaxation of impurity ions, which can agree well with the experiment results. The effect of impurity ions on the property modification of LN crystals is also discussed according to our calculated results.

  6. The H+ related defects in near-stoichiometric lithium niobate crystals investigated by domain reversal

    NASA Astrophysics Data System (ADS)

    Yan, Wenbo; Kong, Yongfa; Shi, Lihong; Xie, Xiang; Li, Xiaochun; Xu, Jingjun; Lou, Cibo; Liu, Hongde; Zhang, Wanlin; Zhang, Guangyin

    2004-07-01

    Domain reversal and heat treatment were carried out on near-stoichiometric lithium niobate crystals and H+ related defect structure of this crystal was studied through infrared absorption spectra. It is found that the position and halfwidth of some deconvoluted peaks of absorption band change apparently during domain reversal and heat treatment. According to these experimental results, a more suitable model about the location of Li-vacancy in LiNbO3 is introduced. In this model, the four Li vacancies, charge-compensating an anti-site Nb5+ ion (Nb4+Li), occupy two types of lattice positions: three of them at the nearest Li-sites Nb4+Li and the other one at a nearer Li-site above the same oxygen plane with Nb4+Li.

  7. Bending waveguides made in x-cut lithium niobate crystals for technological applications

    NASA Astrophysics Data System (ADS)

    Guarepi, V.; Perrone, C.; Aveni, M.; Videla, F.; Torchia, GA

    2015-12-01

    In this paper we analyse the performance of several designs of integrated optical deviators made in x-cut lithium niobate crystals by means of femtosecond laser writing using the double line approach. Straight and bent guiding structures have been designed and implemented using this technique. Well-confined propagation modes at communication wavelengths (1.55 μm) were conducted in these structures with acceptable overall losses (less than 2 dB cm-1). Further, a discussion about the optical propagation losses for curved and straight deviators devices is included in this work. At a low aperture angle (less than 0.2°), as expected, low losses were determined for both structures; however, a weak output light was observed for large angles (greater than 0.2°) in the straight optical circuits. In contrast, a smooth variation of the output was measured for the bent structures. The results presented in this paper support the possibility of the technological implementation of integrated optical circuits for optical communications fabricated with ultrashort laser writing in lithium niobate crystals. In addition, some hypotheses of loss mechanisms that are normally not considered are discussed in order to explain the differences between the measured values and predictions obtained by calculating with the usual models.

  8. Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator.

    PubMed

    Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F; Joh, Han-Ik; Jo, Seong Mu

    2016-11-11

    Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB.

  9. Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator

    NASA Astrophysics Data System (ADS)

    Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F.; Joh, Han-Ik; Jo, Seong Mu

    2016-11-01

    Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB.

  10. Effect of the Crystallization Process on the Marginal and Internal Gaps of Lithium Disilicate CAD/CAM Crowns

    PubMed Central

    Kim, Jae-Hong; Oh, Seunghan; Uhm, Soo-Hyuk

    2016-01-01

    The aim of this study is to quantify the effect of the crystallization process on lithium disilicate ceramic crowns fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system and to determine whether the effect of crystallization is clinically acceptable by comparing values of fit before and after the crystallization process. The mandibular right first molar was selected as the abutment for the experiments. Fifteen working models were prepared. Lithium disilicate crowns appropriate for each abutment were prepared using a commercial CAD/CAM system. Gaps in the marginal area and 4 internal areas of each crown were measured twice—before and after crystallization—using the silicone replica technique. The mean values of fit before and after crystallization were analyzed using a paired t-test to examine whether the conversion that occurred during crystallization affected marginal and internal gaps (α = 0.05). Gaps increased in the marginal area and decreased in the internal areas after crystallization. There were statistically significant differences in all of the investigated areas (P < 0.05). None of the values for marginal and internal fit of lithium disilicate CAD/CAM crowns after crystallization exceeded 120 μm, which is the clinically acceptable threshold. PMID:27123453

  11. The H+ related defects involved in domain reversal for both near-stoichiometric and heavily Mg-doped lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Yan, W.; Kong, Y.; Shi, L.; Yao, J.; Chen, S.; Sun, L.; Zhao, D.; Xu, J.; Zhang, G.

    2005-02-01

    Domain reversal was performed on both near-stoichiometric and heavily Mg-doped lithium niobate crystals. H+ related defect structures in these two types of crystals were studied through the infrared absorption spectra. It is found that the intensity of some decomposed peaks of absorption band change apparently during domain reversal for near-stoichiometric lithium niobate crystals but not for heavily Mg-doped lithium niobate crystals. According to these experimental results, distinct models about H+ related defect structure in LiNbO3 lattice were supposed for them. Nb4+Li and Mg3-Nb were considered as the centers of H+ related defect complex for near-stoichiometric and heavily Mg-doped lithium niobate crystals respectively. Different behavior of them was used to explain the difference of infrared absorption spectra during domain reversal between two types of crystals.

  12. Two-dimensional mapping of electro-optic phase retardation in lithium niobate crystals by digital holography.

    PubMed

    de Angelis, M; De Nicola, S; Finizio, A; Pierattini, G; Ferraro, P; Grilli, S; Paturzo, M; Sansone, L; Alfieri, D; De Natale, P

    2005-07-01

    We demonstrate accurate two-dimensional mapping of the phase retardation induced by the electro-optic effect in lithium niobate crystals. Off-axis digital holography is used to investigate congruent z-cut crystals. The spatially resolved optical path difference is interferometrically measured while a linearly rising voltage ramp is applied to the crystal. This procedure provides information on the uniformity of crystals' electro-optic properties and offers the ability to detect the presence of defects that is of fundamental importance for reliable processing of photonic devices.

  13. Growth, spectroscopic, dielectric and nonlinear optical studies of semi organic nonlinear optical crystal - L-Alanine lithium chloride

    NASA Astrophysics Data System (ADS)

    Hanumantharao, Redrothu; Kalainathan, S.

    2012-02-01

    A new and efficient semi organic nonlinear optical crystal (NLO) from the amino acid family L-alanine lithium chloride (LAL) has been grown by slow evaporation technique from aqueous solution. The functional groups were identified from NMR spectral studies. Mass spectral analysis shows the molecular ion mass. Dielectric studies has been done for the grown crystal and relative SHG efficiency is measured by Kurtz and Perry method and found to about 0.43 times that of standard potassium dihydrogen phosphate (KDP) crystals. The compound crystallized in non-centrosymmetric space group Pna21. The results have been discussed in detail.

  14. Growth, spectroscopic, dielectric and nonlinear optical studies of semi organic nonlinear optical crystal--L-alanine lithium chloride.

    PubMed

    Hanumantharao, Redrothu; Kalainathan, S

    2012-02-01

    A new and efficient semi organic nonlinear optical crystal (NLO) from the amino acid family L-alanine lithium chloride (LAL) has been grown by slow evaporation technique from aqueous solution. The functional groups were identified from NMR spectral studies. Mass spectral analysis shows the molecular ion mass. Dielectric studies has been done for the grown crystal and relative SHG efficiency is measured by Kurtz and Perry method and found to about 0.43 times that of standard potassium dihydrogen phosphate (KDP) crystals. The compound crystallized in non-centrosymmetric space group Pna21. The results have been discussed in detail.

  15. Charge carrier accumulation in lithium fluoride thin films due to Li-ion absorption by titania (100) subsurface.

    PubMed

    Li, Chilin; Gu, Lin; Guo, Xiangxin; Samuelis, Dominik; Tang, Kun; Maier, Joachim

    2012-03-14

    The thermodynamically required redistribution of ions at given interfaces is being paid increased attention. The present investigation of the contact LiF/TiO(2) offers a highly worthwhile example, as the redistribution processes can be predicted and verified. It consists in Li ion transfer from LiF into the space charge zones of TiO(2). We not only can measure the resulting increase of lithium vacancy conductivity in LiF, we also observe a transition from n- to p-type conductivity in TiO(2) in consistency with the generalized space charge model.

  16. Optical and mechanical properties of MgO crystals implanted with lithium ions

    NASA Astrophysics Data System (ADS)

    Savoini, B.; Cáceres, D.; Vergara, I.; González, R.; da Silva, R. C.; Alves, E.; Chen, Y.

    2004-03-01

    Defect profile induced by implantation of Li+ ions with an energy of 175 keV and a fluence of 1×1017ions/cm2 in MgO single crystals was characterized by Rutherford backscattering and optical absorption measurements. Several absorption bands at 5.0, 3.49, 2.16, and 1.27 eV, identical to those found in neutron irradiated crystals, were observed and have been previously associated with oxygen vacancies and higher-order point defects involving oxygen vacancies. Despite the high fluence of Li+ ions, no evidence was found for the formation of Li nanocolloids during implantation. Nanoindentation experiments demonstrated that both the hardness and Young's modulus were higher in the implanted layer than in the sample before implantation. The maximum values were H=(17.4±0.4) and E=(358±9) GPa, respectively, at a contact depth of ≈165 nm. Thermal annealings in flowing argon at increasing temperatures improved the crystalline quality of the implanted layer. After annealing at 500 K, two extinction bands at ≈2.75 and 3.80 eV emerged. These bands are attributed to Mie scattering from metallic lithium nanocolloids with either a face-centered- or a body-centered-cubic structure. The latter band was almost absent by 950 K. The former reached a maximum intensity after the thermal treatment at 1050 K and disappeared by 1250 K. The behavior of these bands can be satisfactorily explained by the Maxwell-Garnett theory. The decrease in hardening cannot be correlated with the thermal destruction of the absorption bands at 5.0, 3.49, 2.16, and 1.27 eV, but rather with the annihilation of both lithium and oxygen interstitials. Lithium outdiffusion from the implanted region takes place at temperatures of ≈1100 K. It is concluded that the hardening observed in the implanted region was primarily due to the extraordinarily large concentration of both lithium and oxygen interstitials.

  17. Crystal structure of a lithium salt of a glucosyl derivative of lithocholic acid.

    PubMed

    Gubitosi, Marta; Meijide, Francisco; D'Annibale, Andrea; Vázquez Tato, José; Jover, Aida; Galantini, Luciano; Travaglini, Leana; di Gregorio, Maria Chiara; Pavel, Nicolae V

    2016-09-01

    The crystal structure of a Li(+) salt of a glucosyl derivative of lithocholic acid (lithium 3α-(α-d-glucopyranosyl)-5β-cholan-24-oate) has been solved. The crystal belongs to the orthorhombic system, P212121 spatial group, and includes acetone and water in the structure with a 1:1:2 stoichiometry. Monolayers, having a hydrophobic interior and hydrophilic edges, are recognized in the crystal structure. Li(+) is coordinated to three hydroxyl groups of three different glucose residues, with two of them belonging to the same monolayer. A fourth molecule, located in this monolayer, is involved in the coordination of the cation through the carboxylate ion by an electrostatic interaction, thus completing a distorted tetrahedron. All Li(+)-oxygen distances values are very close to the sum of the ionic radius of Li(+) and van der Waals radius of oxygen. Each steroid molecule is linked to other five steroid molecules through hydrogen bonds. Water and acetone are also involved in the hydrogen bond network. A hierarchical organization can be recognized in the crystal, the helical assembly along 21 screw axes being left-handed.

  18. Development of a versatile high temperature top seeded solution growth unit for growing cesium lithium borate crystals.

    PubMed

    Reddy, Babu; Elizabeth, Suja; Bhat, H L; Karnal, A K

    2009-01-01

    The design and fabrication of a state of the art high temperature top seeded solution growth (HTTSSG) unit with seed and crucible rotation options is discussed. Crystals from solid solutions of high viscosity could be grown using the setup. The fabricated setup is used to grow high optical quality single crystals of cesium lithium borate with dimensions 50x40x40 mm(3) for frequency conversion of ir to UV laser through harmonic generation.

  19. Lithium vanadyl oxalatophosphite: Influence of the water content on the crystal structures and the dehydration scheme

    SciTech Connect

    Auguste, S.; Alonzo, V.; Bataille, T.; Le Pollès, L.; Cañón-Mancisidor, W.; Venegas-Yazigi, D.; Le Fur, E.

    2014-03-15

    Two new lithium vanadyl oxalatophosphites have been synthesized by hydrothermal treatment. The respective formula are Li{sub 2}(VOHPO{sub 3}){sub 2}C{sub 2}O{sub 4} 6H{sub 2}O (1) and Li{sub 2}(VOHPO{sub 3}){sub 2}C{sub 2}O{sub 4} 4H{sub 2}O (2). The structures of the compounds have been determined by single crystal X-ray diffraction. Compound 1 crystallizes in triclinic symmetry in space group P-1, a=6.3592(2) Å, b=8.0789(3) Å, c=9.1692(3) Å, α=64.390(2), β=87.277(2)°, γ=67.624(2) and, compound 2 in monoclinic symmetry, space group P2{sub 1}/a, a=6.3555(2) Å b=12.6368(7) Å c=9.0242(4) Å β=105.167(3)°. The vanadium phosphite framework consists of infinite chains of corner-sharing vanadium octahedra and hydrogenophosphite tetrahedra. The oxalate groups ensure the connection between the chains. The lithium ions and the water molecules are located between the anionic [(VO){sub 2}(HPO{sub 3}){sub 2}C{sub 2}O{sub 4}]{sup 2−} layers. Thermal behavior of both compounds was carefully studied by combining thermogravimetric analyses and thermal dependant X-ray diffraction in order to study the thermal stability of the layered oxalatophosphites and to see the influence of the decomposition of the carbon-based anions into the final lithium vanadyl phosphate. Various intermediate phases were evidenced and for both compounds the final product was LiVOPO{sub 4}. -- Graphical abstract: Two new lithium vanadyl oxalatophosphites layered compounds, Li{sub 2} (VOHPO{sub 3}){sub 2}C{sub 2}O{sub 4} 6H{sub 2}O (1) and Li{sub 2} (VOHPO{sub 3}){sub 2}C{sub 2}O{sub 4} 4H{sub 2}O (2) have been hydrothermally synthesized. Lithium ions and water molecules are located between the anionic [(VO){sub 2}(HPO{sub 3}){sub 2}C{sub 2}O{sub 4}]{sup 2−} layers. Thermal behaviors were carefully studied by thermogravimetric and thermal dependant X-ray diffraction. Various intermediate phases were evidenced and for both compounds the final product was LiVOPO{sub 4}. Highlights: • The first

  20. Some Lower Valence Vanadium Fluorides: Their Crystal Distortions, Domain Structures, Modulated Structures, Ferrimagnetism, and Composition Dependence.

    ERIC Educational Resources Information Center

    Hong, Y. S.; And Others

    1980-01-01

    Describes some contemporary concepts unique to the structure of advanced solids, i.e., their crystal distortions, domain structures, modulated structures, ferrimagnetism, and composition dependence. (Author/CS)

  1. [Study on the vacuum ultraviolet transmittance of barium fluoride crystals at different temperature].

    PubMed

    Peng, Ru-Yi; Fu, Li-Ping; Tao, Ye

    2014-03-01

    Two VUV-grade BaF2 windows with 0.5 mm-thick and 1 mm-thick respectively were selected to study the transmittance variety with the temperature. The results show that the cutoff wavelength of BaF2 crystals will shift towards the long wave with the increase in temperature. In a certain temperature range, BaF2 crystals can depress 130.4 nm radiation well, and also has a high transmittance at 135.6 nm. Compared with the reported method in which SrF2 crystals can be applied to suppress 130.4 nm stray light by heating, BaF2 crystal can inhibit the 130. 4 nm emission line completely, and thus reduce the power consumption of the device at the same time. This indicates that BaF2 crystals can play an important role in the ionosphere optical remote sensing detection.

  2. Investigation of pyroelectric electron emission from monodomain lithium niobate single crystals

    NASA Astrophysics Data System (ADS)

    Bourim, El Mostafa; Moon, Chang-Wook; Lee, Seung-Woon; Kyeong Yoo, In

    2006-09-01

    The behaviors of thermally stimulated electron emission from pyroelectric monodomain lithium niobate single crystal (LiNbO 3) were investigated by utilizing a Si p-n junction photodiode as electron detector and a receptive electron beam resist (E-beam resist) as electron collector. In high vacuum (10 -6 Torr), the pyroelectric electron emission (PEE) was found to depend on the exposed emitting polar crystal surface (+ Z face or - Z face) and was significantly influenced by the emitter-electron receiver gap distances. Thus, the PEE from + Z face was detected during heating and was activated, in small gaps (<2 mm), by field emission effect on which was superposed an intense field ionization effect that primed intermittent runway ionizations (plasma breakdown into a glow discharge). In large gaps (>2 mm) the emission was simply mastered by field emission effect. Whereas, The PEE from - Z face was detected during cooling and was solely due to the field ionization effect. Therewith, for small gaps (<2 mm) the emission was governed by intermittent runway ionization ignitions resulting from a high ionization degree leading to dense plasma formation, and for large gaps (>2 mm) PEE was governed by field ionization generating a soft and continuous plasma ambient atmosphere. Significant decrease of electron emission current was observed from + Z face after successive thermal cycles. A fast and fully emission recovery was established after a brief exposure of crystal to a poor air vacuum of 10 -1 Torr.

  3. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    SciTech Connect

    Knudson, Marcus D.; Desjarlais, Michael P.; Lemke, Raymond W.

    2014-10-01

    Shock compression experiments in the few hundred GPa (multi-Mabr) regime were performed on Lithium Deuteride (LiD) single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ~200-600 GPa along the Principal Hugoniot – the locus of end states achievable through compression by large amplitude shock waves – as well as pressure and density of re - shock states up to ~900 GPa. Lastly, the experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  4. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    NASA Astrophysics Data System (ADS)

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-01

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ˜190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ˜920 GPa. The experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.

  5. Integrated opto-microfluidics platforms in lithium niobate crystals for sensing applications

    NASA Astrophysics Data System (ADS)

    Bettella, G.; Pozza, G.; Zaltron, A.; Ciampolillo, M. V.; Argiolas, N.; Sada, C.; Chauvet, M.; Guichardaz, B.

    2015-02-01

    In micro-analytical chemistry and biology applications, droplet microfluidic technology holds great promise for efficient lab-on-chip systems where higher levels of integration of different stages on the same platform is constantly addressed. The possibility of integration of opto-microfluidic functionalities in lithium niobate (LiNbO3) crystals is presented. Microfluidic channels were directly engraved in a LiNbO3 substrate by precision saw cutting, and illuminated by optical waveguides integrated on the same substrate. The morphological characterization of the microfluidic channel and the optical response of the coupled optical waveguide were tested. In particular, the results indicate that the optical properties of the constituents dispersed in the fluid flowing in the microfluidic channel can be monitored in situ, opening to new compact optical sensor prototypes based on droplets generation and optical analysis of the relative constituents.

  6. Fabrication and Characterization of Linear Terahertz Detector Arrays Based on Lithium Tantalate Crystal

    NASA Astrophysics Data System (ADS)

    Li, Weizhi; Wang, Jun; Gou, Jun; Huang, Zehua; Jiang, Yadong

    2015-01-01

    Two samples of 30-pixel linear terahertz detector arrays (TDAs) were fabricated based on lithium tantalate (LT) crystals. Pixel readout circuit (ROC) was designed to extract the weak current signal of TDAs. A test platform was established for performance evaluation of TDA+ROC components. By using a 2.52THz laser as radiation source, the test results reveal that average voltage responsivities of the components were larger than 7000V/W and non-uniformity no more than 2.1%. Average noise equivalent power ( NEP) of one sample was measured to be 1.5×10-9 W/Hz1/2, which is low enough and desirable for high performance THz detector.

  7. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    SciTech Connect

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mabr) regime were performed on Lithium Deuteride (LiD) single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ~200-600 GPa along the Principal Hugoniot – the locus of end states achievable through compression by large amplitude shock waves – as well as pressure and density of re - shock states up to ~900 GPa. Lastly, the experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  8. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    DOE PAGES

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mabr) regime were performed on Lithium Deuteride (LiD) single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ~200-600 GPa along the Principal Hugoniot – the locus of end states achievable through compression by large amplitude shock waves – as well as pressure and density of re - shock states up to ~900 GPa. Lastly, the experimental measurements are compared with recent density functional theorymore » calculations as well as a new tabular equation of state developed at Los Alamos National Labs.« less

  9. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    DOE PAGES

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17–32 km/s. Measurements included pressure, density, and temperature between ~190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ~920 GPa. As a result, the experimental measurements are compared with density functional theory calculations, tabular equation ofmore » state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.« less

  10. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    SciTech Connect

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17–32 km/s. Measurements included pressure, density, and temperature between ~190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ~920 GPa. As a result, the experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.

  11. Fabrication and investigation of TIPE waveguide lenses based on lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Volkov, V. A.; Vyrelkin, V. P.; Gan'shin, V. A.; Kvasha, M. Iu.; Korkishko, Iu. N.

    1987-06-01

    The titanium-interdiffused-proton-exchange (TIPE) process for fabricating waveguide lenses is briefly characterized, and a simpler version of the process is proposed. In this process, a single-mode (wavelength, 0.63 micron) Ti:LiNbO3 waveguide is diffused onto the Y-section of lithium niobate at 980 C for 6 hr. An SiO-SiO2 film is then deposited on the crystal surface which serves as a mask for proton-exchange diffusion. Proton exchange diffusion is carried out in the melts of some stable acid salts, making it possible to fabricate TIPE waveguides in open crucibles in air rather than inside evacuated containers. Experimental results are presented for three hyperbolic structures fabricated by the process described here.

  12. Trace phase formation, crystallization kinetics and crystallographic evolution of a lithium disilicate glass probed by synchrotron XRD technique

    PubMed Central

    Huang, Saifang; Huang, Zhaohui; Gao, Wei; Cao, Peng

    2015-01-01

    X-ray diffraction technique using a laboratory radiation has generally shown limitation in detectability. In this work, we investigated the in situ high-temperature crystallization of a lithium disilicate glass-ceramic in the SiO2–Li2O–CaO–P2O5–ZrO2 system with the aid of synchrotron radiation. The formation of lithium metasilicate and other intermediate phases in trace amount was successfully observed by synchrotron X-ray diffraction (SXRD). The crystallization mechanism in this glass was thus intrinsically revised to be the co-nucleation of lithium metasilicate and disilicate, instead of the nucleation of lithium disilicate only. The phase content, crystallite size and crystallographic evolutions of Li2Si2O5 in the glass-ceramic as a function of annealing temperature were studied by performing Rietveld refinements. It is found that the growth of Li2Si2O5 is constrained by Li2SiO3 phase at 580–700°C. The relationship between the crystallographic evolution and phase transition was discussed, suggesting a common phenomenon of structural response of Li2Si2O5 along its c axis to other silicon-related phases during glass crystallization. PMID:25778878

  13. Crystal structure and chemistry of lithium-bearing trioctahedral micas-3T

    USGS Publications Warehouse

    Brigatti, M.F.; Kile, D.E.; Poppi, L.

    2003-01-01

    Chemical analyses and crystal structure refinements were performed on lithian siderophyllite-3T crystals from granitic pegmatites of the anorogenic Pikes Peak batholith (Colorado) to characterize the crystal chemistry and relations with trioctahedral lithium-bearing micas showing different stacking sequences. Chemical data show that the studied samples fall on the siderophyllite-polylithionite join, closer to the siderophyllite end-member. Single-crystal X-ray refinements were carried out on three samples (two of which were taken from core and rim of the same crystal) in space-group P31 12 (the agreement factor, Robs, varies between 0.034 and 0.036). Mean bond distances and mean electron counts of M1, M2 and M3 octahedral sites indicate an ordered cation distribution with M1 and M3 positions substantially larger than M2. In the sample with the largest iron content, the M2 mean electron count increases as well as the mean distance, whereas remains smaller than or . The tetrahedral cation-oxygen atom mean distances range from 1.614 to 1.638 A and from 1.663 to 1.678 A for T1 and T2 sites, respectively, being consistent with Al3+ enrichment in the T2 sites. The tetrahedral rotation angle, α, is generally small (3.1 ≤ α ≤ 4.6) and decreases with siderophyllite content. As Fe increases, the T1 tetrahedron becomes flatter (112.4 ≤ t1 ≤ 110.5??), whereas T2 tetrahedron distortion appears unchanged (110.7 ≤ T2 ≤ 110.9).

  14. Integrated RF photonic devices based on crystal ion sliced lithium niobate

    NASA Astrophysics Data System (ADS)

    Stenger, Vincent; Toney, James; Pollick, Andrea; Busch, James; Scholl, Jon; Pontius, Peter; Sriram, Sri

    2013-03-01

    This paper reports on the development of thin film lithium niobate (TFLN™) electro-optic devices at SRICO. TFLN™ is formed on various substrates using a layer transfer process called crystal ion slicing. In the ion slicing process, light ions such as helium and hydrogen are implanted at a depth in a bulk seed wafer as determined by the implant energy. After wafer bonding to a suitable handle substrate, the implanted seed wafer is separated (sliced) at the implant depth using a wet etching or thermal splitting step. After annealing and polishing of the slice surface, the transferred film is bulk quality, retaining all the favorable properties of the bulk seed crystal. Ion slicing technology opens up a vast design space to produce lithium niobate electro-optic devices that were not possible using bulk substrates or physically deposited films. For broadband electro-optic modulation, TFLN™ is formed on RF friendly substrates to achieve impedance matched operation at up to 100 GHz or more. For narrowband RF filtering functions, a quasi-phase matched modulator is presented that incorporates domain engineering to implement periodic inversion of electro-optic phase. The thinness of the ferroelectric films makes it possible to in situ program the domains, and thus the filter response, using only few tens of applied volts. A planar poled prism optical beam steering device is also presented that is suitable for optically switched true time delay architectures. Commercial applications of the TFLN™ device technologies include high bandwidth fiber optic links, cellular antenna remoting, photonic microwave signal processing, optical switching and phased arrayed radar.

  15. Crystal chemistry, chemical stability, and electrochemical properties of layered oxide cathodes of lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Choi, Jeh Won

    capability is found to bear a clear relationship to the chemical lithium extraction rate, which decreases with decreasing Co content due to an increasing cation disorder. Additionally, the lithium extraction rate is found to influence the structure of the chemically delithiated end members HxNi 0.5-yMn0.5-yCo2yO2; the structure changes from P3 to O1 to O3 with decreasing Co content 2y. A comparison of the chemical stability of the Na0.75-xCoO 2 system shows that it maintains the theoretical value of the oxidation state of cobalt during chemical sodium extraction to low sodium contents of (0.75-x) ≈ 0.3, while Li1-xCoO2 incorporates protons for (1-x) < 0.5. The differences between two systems are discussed based on the crystal structure and the position of Co3+/4+:3d band relative to the top of the O2-:2p band.

  16. Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator

    PubMed Central

    Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F.; Joh, Han-Ik; Jo, Seong Mu

    2016-01-01

    Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB. PMID:27833132

  17. Isomeric ionic lithium isonicotinate three-dimensional networks and single-crystal-to-single-crystal rearrangements generating microporous materials.

    PubMed

    Abrahams, Brendan F; Dharma, A David; Grannas, Martin J; Hudson, Timothy A; Maynard-Casely, Helen E; Oliver, Graham R; Robson, Richard; White, Keith F

    2014-05-19

    Reaction between LiOH and isonicotinic acid (inicH) in the appropriate solvent or mixture of solvents affords a family of variously solvated forms of a simple ionic lithium salt, viz., Li(+)inic(-)·S (where S = 0.5 morpholine, 0.5 dioxane, 0.25 n-hexanol, 0.5 N-methylpyrrolidinone, 0.5 N,N-dimethylformamide, 0.5 n-propanol, 0.5 cyclohexanol, 0.5 pyridine, 0.5 t-butanol, 0.5 ethanol, and 0.5 methanol). Three-dimensional Li(+)inic(-) frameworks containing solvent-filled channels are present in all of these except for the MeOH and EtOH solvates. The nondirectional character of the electrostatic interactions between the Li(+) and inic(-) ions bestows an element of "plasticity" upon the framework, manifested in the observation of no less than five different framework structures within the family. Unusual single-crystal-to-single-crystal transformations accompany desolvation of Li(+)inic(-)·S in which the Li(+)inic(-) framework undergoes a major rearrangement (from a structure containing "8484 chains" to one with "6666 chains"). The "before and after" structures are strongly suggestive of the mechanism and the driving force for these solid state framework rearrangements: processes which further demonstrate the "plasticity" of the ionic Li(inic) framework. A solid-state mechanism for these desolvation processes that accounts very satisfactorily for the formation of the channels and for the diverse geometrical/topological aspects of the transformation is proposed. The reverse process allows the regeneration of the solvated 8484 form. When the 6666 Li(+)inic(-) form is immersed in carbon disulfide, a single-crystal-to-single-crystal transformation occurs to generate Li(+)inic(-)·0.25CS2. The hydrate, Li(+)inic(-)·2H2O which consists of discrete Li(inic)·H2O chains obtained by recrystallizing the salt from water, can also be obtained by hydration of the 6666 form. A dense 3D network with the formula, Li(inic) can be obtained in a reversible process by the removal of the

  18. Optimal Fluoridation

    PubMed Central

    Lee, John R.

    1975-01-01

    Optimal fluoridation has been defined as that fluoride exposure which confers maximal cariostasis with minimal toxicity and its values have been previously determined to be 0.5 to 1 mg per day for infants and 1 to 1.5 mg per day for an average child. Total fluoride ingestion and urine excretion were studied in Marin County, California, children in 1973 before municipal water fluoridation. Results showed fluoride exposure to be higher than anticipated and fulfilled previously accepted criteria for optimal fluoridation. Present and future water fluoridation plans need to be reevaluated in light of total environmental fluoride exposure. PMID:1130041

  19. Investigation of High-Energetic Transitions in Some Pr3+-Doped Fluoride and Oxide Crystals

    DTIC Science & Technology

    2001-01-01

    3 ÷ (YAP) and LiYF4:Pr 3÷ ( YLF ) crystals investigated in this work were grown by the Czochralski method and contained 0.75at% and 3at% Pr...DISCUSSION The optical properties of Pr3÷ ions in the investigated YAP, YLF and KPLF crystals were previously investigated in spectral ranges of typical...the lower-lying multiplets is observed in the blue, green and red spectral ranges. The lifetimes of the luminescent 3p0 multiplet for YAP, YLF and KPLF

  20. Dynamics recording of holographic gratings in a photochromic crystal of calcium fluoride

    NASA Astrophysics Data System (ADS)

    Borisov, Vladimir N.; Barausova, Ekaterina V.; Veniaminov, Andrey V.; Andervaks, Alexandr E.; Shcheulin, Alexandr S.; Ryskin, Alexandr I.

    2016-08-01

    Dynamics of diffraction efficiency was monitored during recording a holographic grating in additively coloured CaF2 photochromic crystal at 180-200°C. Reciprocity failure revealed in the study was attributed to diffusion playing the crucial role in grating formation: recording at larger laser power goes faster but requires more energy. The efficiency of a recorded hologram is found to depend on the temperature; maximum diffraction is measured at the temperature far below that of recording, supposedly because of dramatic distortions suffered by the crystal along with exposure.

  1. Application of electrochemical quartz crystal microbalance to lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Kwon, Kyungjung

    An electrochemical quartz crystal microbalance (EQCM) was used in an investigation of the corrosion of aluminum and of the formation of the solid electrolyte interphase (SEI) on carbon in electrolytes appropriate for lithium-ion batteries. Aluminum corrosion in some electrolytes such as LiN(CF3SO 2)2/propylene carbonate was examined and a corrosion mechanism was suggested. The behavior of the carbon electrode in LiClO4 or LiPF 6/EC+DMC was examined by combining electrochemical methods with EQCM. A difficulty encountered in this use of the EQCM was a monotonic decrease in crystal resonant frequency with time. It was determined that this was due to a change in the viscosity of the electrolyte. Viscosities of some electrolytes that contained ethylene carbonate (EC) and dimethyl carbonate (DMC) were measured and they increased when in contact with carbon, nickel, and aluminum electrodes but did not change with time when stored in glass vials. The SO density in LiClO4/EC+DMC was estimated to be about 1.3 g/cm3 by combining the EQCM and ellipsometry.

  2. Development of fluorides for high power laser optics

    SciTech Connect

    Ready, J.F.; Vora, H.

    1980-07-01

    The laser-assisted thermonuclear fusion program has significant needs for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride (LiF) possesses a combination of optical properties which are of potential use. Single-crystalline LiF is limited by low mechanical strength. In this program, we investigated the technique of press-forging to increase the mechanical strength. LiF single crystals were press-forged over the temperature range 300 to 600/sup 0/C to produce fine-grained polycrystalline material.

  3. Systemic fluoride.

    PubMed

    Sampaio, Fábio Correia; Levy, Steven Marc

    2011-01-01

    There is substantial evidence that fluoride, through different applications and formulas, works to control caries development. The first observations of fluoride's effects on dental caries were linked to fluoride naturally present in the drinking water, and then from controlled water fluoridation programs. Other systemic methods to deliver fluoride were later suggested, including dietary fluoride supplements such as salt and milk. These systemic methods are now being questioned due to the fact that many studies have indicated that fluoride's action relies mainly on its post-eruptive effect from topical contact with the tooth structure. It is known that even the methods of delivering fluoride known as 'systemic' act mainly through a topical effect when they are in contact with the teeth. The effectiveness of water fluoridation in many geographic areas is lower than in previous eras due to the widespread use of other fluoride modalities. Nevertheless, this evidence should not be interpreted as an indication that systemic methods are no longer relevant ways to deliver fluoride on an individual basis or for collective health programs. Caution must be taken to avoid excess ingestion of fluoride when prescribing dietary fluoride supplements for children in order to minimize the risk of dental fluorosis, particularly if there are other relevant sources of fluoride intake - such as drinking water, salt or milk and/or dentifrice. Safe and effective doses of fluoride can be achieved when combining topical and systemic methods.

  4. Two-dimensional correlation infrared spectroscopic study on the crystallization and gelation of poly(vinylidene fluoride) in cyclohexanone.

    PubMed

    Peng, Yun; Sun, Bingjie; Wu, Peiyi

    2008-03-01

    Poly(vinylidene fluoride) (PVDF) converts easily into a thermo-reversible gel through crystallization by standing at room temperature in cyclohexanone. In this study, the Fourier transform infrared (FT-IR) spectra were measured continuously at room temperature during the conversion of the solution into a gel. The IR difference spectra derived from these spectra by absorbance subtraction clearly indicate the presence of PVDF alpha-crystallites in the gel due to the presence of absorption bands corresponding to the TG+TG- conformation of the alpha-phase. In the time interval from 25 to 45 min after the beginning of the experiment, the IR bands of PVDF increased dramatically, indicating the conversion of polymer chains from random statistical coils to the ordered TG+TG- conformation (alpha-form). In the time interval from 45 to 90 min, the IR bands of PVDF increased slowly, reflecting no further crystallization. Using two-dimensional (2D) IR analysis, it could be shown that the nu(C=O) absorption band of cyclohexanone changed during the gelation process. During the conformational ordering process (25-45 min), the nu(C=O) absorption band of the cyclohexanone dimer (1707 cm(-1)) decreased while the corresponding band of the monomer at 1718 cm(-1) increased. Furthermore, a new band at 1695 cm(-1) increased, which could be assigned to C=O groups of the solvent interacting with the CF2 groups in the polymer chain. The bands of the crystalline PVDF share positive cross-peaks with the bands of cyclohexanone, which indicates that the chain of PVDF changed prior to the cyclohexanone molecules during the conformational ordering process. However, these positive cross-peaks disappeared during the crystallization process, which means that the chain of PVDF changed synchronously with the solvent molecules. As for the bands of PVDF chains, the band at 762 cm(-1) varied prior to the bands at 873 cm(-1) and 796 cm(-1) during the conformational ordering process. The 762 cm(-1

  5. Optical properties of Eu{sup 2+} doped antipervoskite fluoride single crystals

    SciTech Connect

    Daniel, D. Joseph; Ramasamy, P.; Nithya, R.; Madhusoodanan, U.

    2013-02-05

    Single crystals of pure and Eu{sup 2+} doped LiBaF{sub 3} have been grown from melt by using a vertical Bridgman-Stockbarger method. Absorption and luminescence spectra for pure and rare-earth-doped LiBaF{sub 3} were studied. At ambient conditions the photoluminescence spectra consisted of sharp lines peaked at {approx}359 nm attributed to the {sup 6}P7/2{yields}{sup 8}S7/2 transitions in the 4f{sub 7} electronic configuration of Eu{sup 2+} and a broad band extending between 370 and 450 nm attributed to Eu{sup 2+} trapped exciton recombination. The effect of {sup 60}Co gamma irradiation has also been investigated.

  6. Visible laser operation of Pr3+-doped fluoride crystals pumped by a 469 nm blue laser.

    PubMed

    Xu, Bin; Camy, Patrice; Doualan, Jean-Louis; Cai, Zhiping; Moncorgé, Richard

    2011-01-17

    We report continuous-wave (CW) laser operation of Pr3+-doped LiLuY4, LiYF4 and KY3F10 single crystals in the Red, Orange and Green spectral regions by using a new pumping scheme. The pump source is an especially developed compact, slightly tunable and intracavity frequency-doubled diode-pumped Nd:YAG laser delivering a CW output power of 0.9W at 469.12 nm. At this pump wavelength, efficient room temperature laser emissions corresponding to the 3P0→3F2, 3P0→3H6 and 3P1→3H5 Pr3+ transitions are observed. While a maximum slope efficiency of 45% is obtained in the red with Pr:LiYF4, the demonstration is made for the first time of the orange laser operation of Pr:KY3F10 at about 610 nm.

  7. Raman spectra of lithium niobate crystals heavily doped with zinc and magnesium

    NASA Astrophysics Data System (ADS)

    Sidorov, N. V.; Palatnikov, M. N.

    2016-12-01

    We have examined the Raman spectra of heavily doped lithium niobate single crystals (at close-to-threshold concentrations of doping cations): LiNbO3:Zn (4.5 mol % ZnO), LiNbO3:Mg (5.01 mol %):Fe (0.005 mol %), LiNbO3:Mg (5.1 mol %), and LiNbO3:Mg (5.3 mol % MgO). Low-intensity lines with frequencies at 209, 230, 298, 694, and 880 cm-1 have been revealed for the first time. Analysis of the data from the literature on lattice dynamics calculations from first principles (ab initio) does not make it possible to unambiguously state that these lines correspond to fundamental vibrations of the A2 symmetry species, which are forbidden for the C3 V 6 ( R3c) space group. At the same time, ab initio calculations unambiguously indicate that the experimentally observed low-intensity "superfluous" lines with the frequencies at 104 and 119 cm-1 cannot correspond to vibrations of the A2 symmetry species. It is most likely that they correspond to two-particle states of acoustic phonons with a total wave vector equal to zero.

  8. Preparation and Crystal Structure of Lithium Nitride Chloride Li 4NCl

    NASA Astrophysics Data System (ADS)

    Marx, Rupert

    1997-02-01

    Li4NCl was prepared from Li3N and dry OH-free LiCl at 450°C. It is found to be the more nitrogen-rich of two compounds in the quasi-binary system Li3-2xN1-xClx. Following unit cell indexing using laboratory X-ray powder data, the previously unknown structure of the title compound was solved from neutron powder diffraction data recorded using the flat-cone and powder diffractometer E2 at the Berlin BERII reactor. Li4NCl crystallizes in the hexagonal rhombohedral space groupRoverline3=m(No. 166),a=366.225(4),c=1977.18(4) pm with three formula units per unit cell. Its structure comprises a 1:1-ordering variant of a cubic close anion packing, N3-and Cl-forming layers perpendicular to [001]. Li atoms occupy all the triangular voids of the N layers and all the NCl3-tetrahedral holes. Nitrogen is in lithium nitride-like hexagonal bipyramidal coordination by Li, the equatorial six-membered ring being slightly puckered, while Cl is in distorted octahedral coordination. Calculation of the Madelung part of the lattice energy shows that the nitrogen hexagonal bipyramidal coordination polyhedron, peculiar for Li4NCl and the Li3N parent structure, is in agreement with a simple ionic picture and does not imply any covalent bonding.

  9. The crystal structure and microtwinning of ferro-pedrizite, a new lithium amphibole

    NASA Astrophysics Data System (ADS)

    Aksenov, S. M.; Rastsvetaeva, R. K.; Konovalenko, S. I.; Ananyev, S. A.; Chukanov, N. V.; Miroshkina, A. E.

    2015-07-01

    The structure of ferro-pedrizite—a new lithium mineral of the amphibole supergroup—has been studied by single-crystal X-ray diffraction. Fe2+ ions dominate over Mg in the chemical composition of this mineral. The parameters of the monoclinic unit cell are a = 9.3716(4) Å, b = 17.649(1) Å, c = 5.2800(6) Å, and β = 102.22(1)°. The experimental set of intensities contains a large number of significant reflections (~10%), which violate the Clattice. Consideration of pseudomerohedral twinning (matrix [1 0 0/00/-3/4 0]) allowed us to solve and refine the structure within the sp. gr. C2/ m to the final value R = 3.9% in the anisotropic approximation of atomic displacements using 4843 I > 2σ( I). The twin components are found to be 0.681(3)/0.319(3). Twinning has been revealed for the first time in amphiboles of the pedrizite family. The idealized formula of ferro-pedrizite ( Z = 2) is determined as NaLi2(Al2Li)[Si8O22](OH)2.

  10. Prediction of different crystal structure phases in metal borides: A lithium monoboride analog to MgB2

    NASA Astrophysics Data System (ADS)

    Kolmogorov, Aleksey N.; Curtarolo, Stefano

    2006-05-01

    Modern compound prediction methods can efficiently screen large numbers of crystal structure phases and direct the experimental search for new materials. One of the most challenging problems in alloy theory is the identification of stable phases with a never seen prototype; such predictions do not always follow rational strategies. While performing ab initio data mining of intermetallic compounds we made an unexpected discovery: even in such a well-studied class of systems as metal borides there are previously unknown layered phases comparable in energy to the existing ones. With ab initio calculations we show that the new metal-sandwich (MS) lithium monoboride phases are marginally stable under ambient conditions but become favored over the known stoichiometric compounds under moderate pressures. The MS lithium monoboride exhibits electronic features similar to those in magnesium diboride and is expected to be a good superconductor.

  11. Hydrothermal synthesis and crystal structure of a new lithium copper bismuth oxide, LiCuBiO4

    NASA Astrophysics Data System (ADS)

    Kumada, Nobuhiro; Nakamura, Ayumi; Miura, Akira; Takei, Takahiro; Azuma, Masaki; Yamamoto, Hajime; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2017-01-01

    A new lithium copper bismuth oxide, LiCuBiO4 was prepared by hydrothermal reaction using NaBiO30.1*4H2O. The crystal structural model of this compound was refined by using synchrotron X-ray powder diffraction data. This bismuthate has the LiCuSbO4 related structure with the orthorhombic cell (Space group: Pnma) of a=10.9096(9), b=5.8113(5) and c=5.0073(4) Å, and the final R-factors were Rwp=4.84 and Rp=3.58%. This compound is the first example of a lithium copper bismuthate containing Bi5+. An antiferromagnetic ordering of Cu2+ moment was observed at 6 K.

  12. Growth and photorefractive properties of Mg, Fe co-doped near-stoichiometric lithium tantalate single crystals

    NASA Astrophysics Data System (ADS)

    Hsu, W. T.; Chen, Z. B.; You, C. A.; Huang, S. W.; Liu, J. P.; Lan, C. W.

    2010-07-01

    Mg, Fe co-doped near-stoichiometric lithium tantalate (SLT) crystals were successfully grown by the zone-leveling Czochralski (ZLCz) technique and the holographic properties were measured by the two-beam coupling method. The fundamental optical properties of crystals were measured by employing the UV-vis-NIR spectrometer and Fourier transformation infrared spectrophotometer as well. By the chemical analysis, the Li/Ta, Mg/Ta and Fe/Ta ratios of the crystals were obtained and the Li/Ta ratios of the crystals were all close to the theoretical limitation of 0.98. In the holographic properties, the recording time constant, erasing time constant, dynamic range, and sensitivity decreased with light intensity; but the maximum diffraction efficiency showed an opposite trend. Furthermore, the diffraction efficiency, dynamic range and sensitivity of the crystals were improved with a relatively higher Fe/Ta ratio. In comparison with Mn-LT crystals, the Mg, Fe co-doped SLT crystal showed the superior photorefractive properties indicating that it could be a promising new material for lifetime holographic data storage.

  13. Test beam results with a sampling calorimeter of cerium fluoride scintillating crystals and tungsten absorber plates for calorimetry at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Becker, R.; Dissertori, G.; Djambazov, L.; Donegà, M.; Dröge, M.; Haller, C.; Horisberger, U.; Lustermann, W.; Nessi-Tedaldi, F.; Quittnat, M.; Pandolfi, F.; Peruzzi, M.; Schönenberger, M.; Cavallari, F.; Dafinei, I.; Diemoz, M.; D`Imperio, G.; del Re, D.; Gelli, S.; Jorda Lope, C.; Meridiani, P.; Micheli, F.; Nuccetelli, M.; Organtini, G.; Paramatti, R.; Pellegrino, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Soffi, L.; Tabarelli de Fatis, T.; Martelli, A.; Monti, V.; Pastrone, N.; Trapani, P. P.; Candelise, V.; Della Ricca, G.

    2016-07-01

    A sampling calorimeter using cerium fluoride scintillating crystals as active material, interleaved with absorber plates made of tungsten, and read out by wavelength-shifting fibres has been tested with high-energy electron beams at the CERN SPS H4 beam line, as well as with lower-energy beams at the INFN Frascati Beam Test Facility in Italy. Energy resolution studies revealed a low stochastic term (< 10 % /√{ E }). This result, combined with high radiation hardness of the material used, marks this sampling calorimeter as a good candidate for the detectors' forward regions during the high luminosity phase of LHC.

  14. Lithium diffusion in congruent LiNbO3 single crystals at low temperatures probed by neutron reflectometry.

    PubMed

    Hüger, E; Rahn, J; Stahn, J; Geue, T; Heitjans, P; Schmidt, H

    2014-02-28

    The self-diffusion of lithium in congruent LiNbO3 single crystals was investigated at low temperatures between 379 and 523 K by neutron reflectometry. From measurements on (6)LiNbO3 (amorphous film)/(nat)LiNbO3 (single crystal) samples, Li self-diffusivities were determined in single crystals down to extremely low values of 1 × 10(-25) m(2) s(-1) on small length scales of 1-10 nm. The measured diffusivities are in excellent agreement with (extrapolated) literature data obtained by experiments based on Secondary Ion Mass Spectrometry and Impedance Spectroscopy. The tracer diffusivities can be described by a single Arrhenius line over ten orders of magnitude with an activation enthalpy of 1.33 eV, which corresponds to the migration energy of a single Li vacancy. A deviation from the Arrhenius behaviour at low temperatures, e.g., due to defect cluster formation is not observed.

  15. Fluoride evaporation and crystallization behavior of CaF2-CaO-Al2O3-(TiO2) slag for electroslag remelting of Ti-containing steels

    NASA Astrophysics Data System (ADS)

    Shi, Cheng-bin; Cho, Jung-wook; Zheng, Ding-li; Li, Jing

    2016-06-01

    To elucidate the behavior of slag films in an electroslag remelting process, the fluoride evaporation and crystallization of CaF2-CaO-Al2O3-(TiO2) slags were studied using the single hot thermocouple technique. The crystallization mechanism of TiO2-bearing slag was identified based on kinetic analysis. The fluoride evaporation and incubation time of crystallization in TiO2-free slag are found to considerably decrease with decreasing isothermal temperature down to 1503 K. Fish-bone and flower-like CaO crystals precipitate in TiO2-free slag melt, which is accompanied by CaF2 evaporation from slag melt above 1503 K. Below 1503 K, only near-spherical CaF2 crystals form with an incubation time of less than 1 s, and the crystallization is completed within 1 s. The addition of 8.1wt% TiO2 largely prevents the fluoride evaporation from slag melt and promotes the slag crystallization. TiO2 addition leads to the precipitation of needle-like perovskite (CaTiO3) crystals instead of CaO crystals in the slag. The crystallization of perovskite (CaTiO3) occurs by bulk nucleation and diffusion-controlled one-dimensional growth.

  16. Microstructure and defects probed by Raman spectroscopy in lithium niobate crystals and devices

    SciTech Connect

    Fontana, Marc D.; Bourson, Patrice

    2015-12-15

    Raman microprobe applied on LiNbO{sub 3} (LN) crystals and derived materials or devices is shown to be a tool to detect either local variations or changes of the whole structure. Position, width, or intensity of one Raman line can be used as markers of a structural change. Indeed, each Raman line can be assigned to a peculiar ionic motion and is differently sensitive to application of strain, temperature change, and electric field. Some vibrational modes are especially associated to the site of Li ion, or Nb ion, or still oxygen octahedron, so that they can be affected by the introduction of dopant ion on one or another site. Therefore, Raman Spectroscopy (RS) can be used as a site spectroscopy to describe the mechanism of doping incorporation in the LN lattice, allowing the optimization of some linear and non-linear optical properties according to the dopant concentration and substitution site. The composition or the content of non-stoichiometry related defects could be derived from the width of some lines. Any damage or local disorder can be detected by a line broadening. The quality or preservation of the structure after chemical treatment, or laser pulses, can be thus checked. The structure of ion-implanted or proton-exchanged wave-guides and periodically poled lithium niobate as well can be imaged from frequency shift or intensity change of some lines. RS is thus a useful way to control the structure of LN and/or to optimize the preparation parameters and its properties.

  17. Study of beryllium and beryllium-lithium complexes in single-crystal silicon.

    NASA Technical Reports Server (NTRS)

    Crouch, R. K.; Robertson, J. B.; Gilmer, T. E., Jr.

    1972-01-01

    When beryllium is thermally diffused into silicon, it gives rise to acceptor levels 191 and 145 meV above the valence band. Quenching and annealing studies indicate that the 145-meV level is due to a more complex beryllium configuration than the 191-meV level. When lithium is thermally diffused into a beryllium-doped silicon sample, it produces two new acceptor levels at 106 and 81 meV. Quenching and annealing studies indicate that these new levels are due to lithium forming a complex with the defects responsible for the 191- and 145-meV beryllium levels, respectively. Electrical measurements imply that the lithium impurity ions are physically close to the beryllium impurity atoms. The ground state of the 106-meV beryllium-lithium level is split into two levels, presumably by internal strains. Tentative models are proposed to explain these results.

  18. An insight into crystal, electronic, and local structures of lithium iron silicate (Li2FeSiO4) materials upon lithium extraction

    NASA Astrophysics Data System (ADS)

    Kamon-in, O.; Klysubun, W.; Limphirat, W.; Srilomsak, S.; Meethong, N.

    2013-05-01

    Recently, orthosilicate, Li2MSiO4 (where M=transition metal) materials have been attracting considerable attention for potential use as a new generation cathode for Li-ion batteries due to their safety, low toxicity, and low cost characteristics. In addition, the presence of two Li+ ions in the molecule offers a multiple electron-charge transfer (M2+/M3+ and M3+/M4+ redox couples), thus allowing a high achievable capacity of more than 320 mA h/g per M unit. Good electrochemical properties of Li2FeSiO4 have been reported through several approaches such as downsizing of the particles, carbon-coating, etc. However, in addition to electrochemical performance, fundamental understanding regarding crystal, electronic and local structure changes during charge/discharge processes is also important and needs more rigorous investigation. In this work, lithium iron silicates (Li2FeSiO4/C) in space group of Pnma: a=10.6671(3) Å, b=6.2689(2) Å, and c=5.0042(2) Å have been prepared by solid-state reaction. The synthesized as well as chemical delithiated samples have been characterized by XRD, HRTEM, AAS and XAS techniques. We will show the results focusing on Fe K-edge XANES, EXAFS, HRTEM and XRD of the Li2-xFeSiO4 samples and discuss how the crystal, electronic, and local structure changes upon Li+ de-intercalation.

  19. Dentifrice Fluoride

    NASA Astrophysics Data System (ADS)

    Rakita, Philip E.

    2004-05-01

    The effectiveness of the fluoride ion in lowering the incidence of dental caries is a major factor in the field of dental health. Observations and research studies in the first half of the 20th century have lead to the widespread adoption of fluoridated water and the use of inorganic fluoride compounds in oral care products, such as toothpaste and dental rinses. This article provides a brief review of the types of compounds used and the chemistry involved.

  20. Bulk crystal growth, optical, mechanical and ferroelectric properties of new semiorganic nonlinear optical and piezoelectric Lithium nitrate monohydrate oxalate single crystal

    NASA Astrophysics Data System (ADS)

    Dalal, Jyoti; Kumar, Binay

    2016-01-01

    New semiorganic nonlinear optical single crystals of Lithium nitrate oxalate monohydrate (LNO) were grown by slow evaporation solution technique. Single crystal X-ray diffraction study indicated that LNO crystal belongs to the triclinic system with space group P1. Various functional groups present in the material were identified by FTIR and Raman analysis. UV-vis study showed the high transparency of crystals with a wide band gap 5.01 eV. Various Optical constants i.e. Urbach energy (Eu), extinction coefficient (K), refractive index, optical conductivity, electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data which have applications in optoelectronic devices. A sharp emission peak was found at 438 nm in photoluminescence measurement, which revealed suitability of crystal for fabricating violet lasers. In dielectric studies, a peak has been observed at 33 °C which is due to ferroelectric to paraelectric phase transition. Piezoelectric charge coefficients (d33 = 9.2 pC/N and g33) have been calculated, which make it a suitable for piezoelectric devices applications. In ferroelectric studies, a saturated loop was found in which the values of coercive field and remnant polarization were found to be 2.18 kV/cm and 0.39 μC/cm2, respectively. Thermal behavior was studied by TGA and DSC studies. The relative SHG efficiency of LNO was found to be 1.2 times that of KDP crystal. In microhardness study, Meyer's index value was found to be 1.78 which revealed its soft nature. These optical, dielectric, piezoelectric, ferroelectric, mechanical and non-linear optical properties of grown crystal establish the usefulness of this material for optoelectronics, non-volatile memory and piezoelectric devices applications.

  1. Bottled Water and Fluoride

    MedlinePlus

    ... Fluoridation Journal Articles for Community Water Fluoridation Bottled Water Recommend on Facebook Tweet Share Compartir Consumers drink ... questions about bottled water and fluoride. Does bottled water contain fluoride? Bottled water products may contain fluoride, ...

  2. Role of surface ligands in the nanoparticle assemblies: a case study of regularly shaped colloidal crystals composed of sodium rare earth fluoride.

    PubMed

    Feng, Wei; Sun, Ling-Dong; Yan, Chun-Hua

    2011-04-05

    Assembly of nanoparticles is a promising route to fabricate devices from nanomaterials. Colloidal crystals are well-defined three-dimensional assemblies of nanoparticles with long-range ordered structures and crystalline symmetries. Here, we use a solvent evaporation induced assembly method to obtain colloidal crystals composed of polyhedral sodium rare earth fluoride nanoparticles. The building blocks exhibit the same crystalline orientation in each colloidal crystal as indicated in electron diffraction patterns. The driving force of the oriented assembly is ascribed to the facet-selected capping of oleic acid molecules on {110} facets of the nanoparticles, and the favorable coordination behavior of OA molecules is explained by the steric hindrance determined adsorption based on the studies of the surface atomic structure of nanocrystals and molecular mechanics simulation of OA molecules. The capping ligands also provide hydrophobic interactions between nanoparticles and further direct the oriented assembly process to construct a face-centered cubic structure. These results not only provide a new type of building block for colloidal crystals, but also clarify the important role of surface ligands, which determine the packed structure and orientations of nanoparticles in the assemblies.

  3. A study of beryllium and beryllium-lithium complexes in single crystal silicon

    NASA Technical Reports Server (NTRS)

    Crouch, R. K.; Robertson, J. B.; Gilmer, T. E., Jr.

    1972-01-01

    When beryllium is thermally diffused into silicon, it gives rise to acceptor levels 191 MeV and 145 meV above the valence band. Quenching and annealing studies indicate that the 145-MeV level is due to a more complex beryllium configuration than the 191-MeV level. When lithium is thermally diffused into a beryllium-doped silicon sample, it produces two acceptor levels at 106 MeV and 81 MeV. Quenching and annealing studies indicate that these levels are due to lithium forming a complex with the defects responsible for the 191-MeV and 145-MeV beryllium levels, respectively. Electrical measurements imply that the lithium impurity ions are physically close to the beryllium impurity atoms. The ground state of the 106-MeV beryllium level is split into two levels, presumably by internal strains. Tentative models are proposed.

  4. Variation and fractionation of lithium isotope ratios within single tourmaline crystals in the pegmatites of the Black Hills, SD

    NASA Astrophysics Data System (ADS)

    Gross, M.; Nabelek, P. I.

    2012-12-01

    Lithium isotopes are quickly becoming a valuable geochemical tool, providing insight into a broad range of studies. Li isotopes have been utilized in studies with subjects ranging from mantle processes to planetary accretion on stars. Yet, as an emerging technique, a number of uncertainties remain to be resolved. Two basic questions must be answered in order to apply isotope studies in a meaningful way: How do isotopes fractionate from each other and what do the isotope ratios mean? Previous studies on intra-crystal Li isotope signatures in tourmaline are extremely limited. One study showed roughly homogenous isotope profile using secondary ion mass spectroscopy (SIMS) analysis (Ludwig et al. 2011). If Li isotopes are in fact variable within individual crystals, however, it has implications for previous models of pegmatite formation reached using Li isotopes, as well as the root cause of Li isotope fractionation in tourmaline. For this study, tourmaline samples were collected from several texturally different pegmatite localities in the Black Hills, SD. Lithium concentrations and isotope ratios were measured along numerous points in a tourmaline crystal to discern how they change within a single crystal. The tourmaline was dissolved by an alkali fusion technique. Concentrations were determined at the University of Missouri using a Perkin-Elmer Optima 3300 Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Isotope measurements were performed at University of Maryland-College Park by a Nu Plasma Multi-collector ICP-MS. The procedure followed the three-column cation exchange chromatography method. Additionally, elemental mapping was performed on one sample using the JEOL JXA-8200 Superprobe at Washington University in St. Louis. Results of this research reveal that extreme fractionation of Li is possible within single tourmaline crystals. The δ7Li values measured are among the highest measured in rocks, though the average for each crystal falls

  5. Enhanced electroactive and mechanical properties of poly(vinylidene fluoride) by controlling crystallization and interfacial interactions with low loading polydopamine coated BaTiO₃.

    PubMed

    Jia, Nan; Xing, Qian; Liu, Xu; Sun, Jing; Xia, Guangmei; Huang, Wei; Song, Rui

    2015-09-01

    Poly(vinylidene fluoride) (PVDF) is a semi-crystalline polymer and the polar β-phase of PVDF shows superb electroactive properties. In order to enhance the β-phase of PVDF, extreme low content of BaTiO3 nanoparticles (BT-NPs) coated with polydopamine (Pdop) were incorporated into PVDF matrix by solution casting. The β-phase of the resulting PVDF nanocomposites film was dramatically increased and the d33 value reached 34.3±0.4 pCN(-1). It is found that the Pdop layer could improve the dispersibility and stability of the BT NPs in solution and endow the BT NPs good dispersity in the PVDF matrix. Moreover, the interfacial interaction between PVDF chains and the surface of BT-Pdop nanoparticles (BT-Pdop NPs) were revealed, in which the CF2 groups on PVDF could interact with the electron-rich plane of aromatic ring of Pdop moiety. This interaction, led to the increase of the crystallization activation energy as derived from the DSC nonisothermal crystallization measurement. The α-β crystal transformation, organization of interfacial interactions as well as the prevention of agglomeration of BT-NPs confer the improvement of mechanical and thermal properties of PVDF, such as toughness, tensile strength, elongation at break, and thermal conductivity.

  6. Inhibition of Maize Root H+-ATPase by Fluoride and Fluoroaluminate Complexes.

    PubMed Central

    Facanha, A. R.; De Meis, L.

    1995-01-01

    Vesicles derived from maize roots retain a membrane-bound H+-ATPase that is able to pump H+ at the expense of ATP hydrolysis. The H+ pumping and the ATPase activity of these vesicles are inhibited by lithium fluoride and by the complex formed between fluoride and aluminum. The inhibition promoted by lithium fluoride increases as the MgCl2 concentration in the medium is increased from 2 to 20 mM. The inhibitory activity of both lithium fluoride and aluminum fluoride increases as the temperature of the medium is increased from 20 to 35[deg]C. Inorganic phosphate (10-40 mM) inhibits the H+ -ATPase at pH 6.5 but not at pH 7.0, and at both pH values, it antagonizes the inhibition promoted by lithium fluoride and fluoroaluminate complexes. PMID:12228469

  7. Crystal and mol­ecular structures of two silver(I) amidinates, including an unexpected co-crystal with a lithium amidinate

    PubMed Central

    Wang, Sida; Harmgarth, Nicole; Liebing, Phil; Edelmann, Frank T.

    2016-01-01

    The silver(I) amidinates bis­[μ-N 1,N 2-bis­(propan-2-yl)benzamidinato-κ2 N 1:N 2]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(NiPr)2}]2 (1), and bis­(μ-N 1,N 2-di­cyclohexyl-3-cyclo­propyl­propynamidinato-κ2 N 1:N 2)disilver(I), [Ag2(C18H27N2)2] or [Ag{cyclo-C3H5–C≡C–C(NCy)2}]2 (2a), exist as centrosymmetric dimers with a planar Ag2N4C2 ring and a common linear coordination of the metal atoms in the crystalline state. Moiety 2a forms a co-crystal with the related lithium amidinate, namely bis­(μ-N 1,N 2-di­cyclo­hexyl-3-cyclo­propyl­propynamidinato-κ2 N 1:N 2)disilver(I) bis­(μ-N 1,N 2-di­cyclo­hexyl-3-cyclo­propyl­propynamidinato-κ3 N 1,N 2:N 1)bis­(tetra­hydro­furan-κO)lithium(I) toluene monosolvate, [Ag2(C18H27N2)2][Li2(C18H27N2)2(C4H8O)2]·C7H8 or [Ag{cyclo-C3H5–C≡C–C(NCy)2}]2[Li{cyclo-C3H5–C≡C–C(NCy)2}(THF)]2·C7H8, composed as 2a × 2b × toluene. The lithium moiety 2b features a typical ladder-type dimeric structure with a distorted tetra­hedral coordination of the metal atoms. In the silver(I) derivatives 1 and 2a, the amidinate ligand adopts a μ-κN:κN′ coordination, while it is a μ-κN:κN:κN′-coordination in the case of lithium derivative 2b. PMID:27980831

  8. Crystal and mol-ecular structures of two silver(I) amidinates, including an unexpected co-crystal with a lithium amidinate.

    PubMed

    Wang, Sida; Harmgarth, Nicole; Liebing, Phil; Edelmann, Frank T

    2016-12-01

    The silver(I) amidinates bis-[μ-N(1),N(2)-bis-(propan-2-yl)benzamidinato-κ(2)N(1):N(2)]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(N (i) Pr)2}]2 (1), and bis-(μ-N(1),N(2)-di-cyclohexyl-3-cyclo-propyl-propynamidinato-κ(2)N(1):N(2))disilver(I), [Ag2(C18H27N2)2] or [Ag{cyclo-C3H5-C≡C-C(NCy)2}]2 (2a), exist as centrosymmetric dimers with a planar Ag2N4C2 ring and a common linear coordination of the metal atoms in the crystalline state. Moiety 2a forms a co-crystal with the related lithium amidinate, namely bis-(μ-N(1),N(2)-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ(2)N(1):N(2))disilver(I) bis-(μ-N(1),N(2)-di-cyclo-hexyl-3-cyclo-propyl-propynamidinato-κ(3)N(1),N(2):N(1))bis-(tetra-hydro-furan-κO)lithium(I) toluene monosolvate, [Ag2(C18H27N2)2][Li2(C18H27N2)2(C4H8O)2]·C7H8 or [Ag{cyclo-C3H5-C≡C-C(NCy)2}]2[Li{cyclo-C3H5-C≡C-C(NCy)2}(THF)]2·C7H8, composed as 2a × 2b × toluene. The lithium moiety 2b features a typical ladder-type dimeric structure with a distorted tetra-hedral coordination of the metal atoms. In the silver(I) derivatives 1 and 2a, the amidinate ligand adopts a μ-κN:κN' coordination, while it is a μ-κN:κN:κN'-coordination in the case of lithium derivative 2b.

  9. Fabrication of polarization-independent waveguides deeply buried in lithium niobate crystal using aberration-corrected femtosecond laser direct writing

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Qi, Jia; Liu, Zhengming; Liao, Yang; Chu, Wei; Cheng, Ya

    2017-01-01

    Writing optical waveguides with femtosecond laser pulses provides the capability of forming three-dimensional photonic circuits for manipulating light fields in both linear and nonlinear manners. To fully explore this potential, large depths of the buried waveguides in transparent substrates are often desirable to facilitate achieving vertical integration of waveguides in a multi-layer configuration, which, however, is hampered by rapidly degraded axial resolution caused by optical aberration. Here, we show that with the correction of the spherical aberration, polarization-independent waveguides can be inscribed in a nonlinear optical crystal lithium niobate (LN) at depths up to 1400 μm, which is more than one order of magnitude deeper than the waveguides written with aberration uncorrected femtosecond laser pulses. Our technique is beneficial for applications ranging from miniaturized nonlinear light sources to quantum information processing.

  10. Fabrication of polarization-independent waveguides deeply buried in lithium niobate crystal using aberration-corrected femtosecond laser direct writing

    PubMed Central

    Wang, Peng; Qi, Jia; Liu, Zhengming; Liao, Yang; Chu, Wei; Cheng, Ya

    2017-01-01

    Writing optical waveguides with femtosecond laser pulses provides the capability of forming three-dimensional photonic circuits for manipulating light fields in both linear and nonlinear manners. To fully explore this potential, large depths of the buried waveguides in transparent substrates are often desirable to facilitate achieving vertical integration of waveguides in a multi-layer configuration, which, however, is hampered by rapidly degraded axial resolution caused by optical aberration. Here, we show that with the correction of the spherical aberration, polarization-independent waveguides can be inscribed in a nonlinear optical crystal lithium niobate (LN) at depths up to 1400 μm, which is more than one order of magnitude deeper than the waveguides written with aberration uncorrected femtosecond laser pulses. Our technique is beneficial for applications ranging from miniaturized nonlinear light sources to quantum information processing. PMID:28112246

  11. Fabrication of polarization-independent waveguides deeply buried in lithium niobate crystal using aberration-corrected femtosecond laser direct writing.

    PubMed

    Wang, Peng; Qi, Jia; Liu, Zhengming; Liao, Yang; Chu, Wei; Cheng, Ya

    2017-01-23

    Writing optical waveguides with femtosecond laser pulses provides the capability of forming three-dimensional photonic circuits for manipulating light fields in both linear and nonlinear manners. To fully explore this potential, large depths of the buried waveguides in transparent substrates are often desirable to facilitate achieving vertical integration of waveguides in a multi-layer configuration, which, however, is hampered by rapidly degraded axial resolution caused by optical aberration. Here, we show that with the correction of the spherical aberration, polarization-independent waveguides can be inscribed in a nonlinear optical crystal lithium niobate (LN) at depths up to 1400 μm, which is more than one order of magnitude deeper than the waveguides written with aberration uncorrected femtosecond laser pulses. Our technique is beneficial for applications ranging from miniaturized nonlinear light sources to quantum information processing.

  12. Enhanced Cherenkov phase matching terahertz wave generation via a magnesium oxide doped lithium niobate ridged waveguide crystal

    NASA Astrophysics Data System (ADS)

    Takeya, K.; Minami, T.; Okano, H.; Tripathi, S. R.; Kawase, K.

    2017-01-01

    When combined with a nonlinear waveguide crystal, Cherenkov phase matching allows for highly effective generation of high power and broadband terahertz (THz) waves. Using a ridged Lithium Niobate (LiNbO3) waveguide coupled with a specially designed silicon lens, we successfully generated THz waves with intensity of approximately three orders of magnitude stronger than those from conventional photoconductive antenna. The broadband spectrum was from 0.1 THz to 7 THz with a maximum dynamic range of 80 dB. The temporal shape of time domain pulse is a regular single cycle which could be used for high depth resolution time of flight tomography. The generated THz wave can also be easily monitored by compact room-temperature THz camera, enabling us to determine the spatial characteristics of the THz propagation.

  13. PARAMAGNETIC RELAXATION IN CRYSTALS.

    DTIC Science & Technology

    CRYSTALS, PARAMAGNETIC RESONANCE, RELAXATION TIME , CRYSTAL DEFECTS, QUARTZ, GLASS, STRAIN(MECHANICS), TEMPERATURE, NUCLEAR SPINS, HYDROGEN, CALCIUM COMPOUNDS, FLUORIDES, COLOR CENTERS, PHONONS, OXYGEN.

  14. Lithium ion diffusion in Li β-alumina single crystals measured by pulsed field gradient NMR spectroscopy

    SciTech Connect

    Chowdhury, Mohammed Tareque Takekawa, Reiji; Iwai, Yoshiki; Kuwata, Naoaki; Kawamura, Junichi

    2014-03-28

    The lithium ion diffusion coefficient of a 93% Li β-alumina single crystal was measured for the first time using pulsed field gradient (PFG) NMR spectroscopy with two different crystal orientations. The diffusion coefficient was found to be 1.2 × 10{sup −11} m{sup 2}/s in the direction perpendicular to the c axis at room temperature. The Li ion diffusion coefficient along the c axis direction was found to be very small (6.4 × 10{sup −13} m{sup 2}/s at 333 K), which suggests that the macroscopic diffusion of the Li ion in the β-alumina crystal is mainly two-dimensional. The diffusion coefficient for the same sample was also estimated using NMR line narrowing data and impedance measurements. The impedance data show reasonable agreement with PFG-NMR data, while the line narrowing measurements provided a lower value for the diffusion coefficient. Line narrowing measurements also provided a relatively low value for the activation energy and pre-exponential factor. The temperature dependent diffusion coefficient was obtained in the temperature range 297–333 K by PFG-NMR, from which the activation energy for diffusion of the Li ion was estimated. The activation energy obtained by PFG-NMR was smaller than that obtained by impedance measurements, which suggests that thermally activated defect formation energy exists for 93% Li β-alumina single crystals. The diffusion time dependence of the diffusion coefficient was observed for the Li ion in the 93% Li β-alumina single crystal by means of PFG-NMR experiments. Motion of Li ion in fractal dimension might be a possible explanation for the observed diffusion time dependence of the diffusion coefficient in the 93% Li β–alumina system.

  15. Optimization of the idler wavelength tunable cascaded optical parametric oscillator based on chirp-assisted aperiodically poled lithium niobate crystal

    NASA Astrophysics Data System (ADS)

    Tao, Chen; Rong, Shu; Ye, Ge; Zhuo, Chen

    2016-01-01

    We present the numerical results for the optimization of the pump-to-idler conversion efficiencies of nanosecond idler wavelength tunable cascaded optical parametric oscillators (OPO) in different wavelength tuning ranges, where the primary signals from the OPO process are recycled to enhance the pump-to-idler conversion efficiencies via the simultaneous difference frequency generation (DFG) process by monolithic aperiodically poled, magnesium oxide doped lithium niobate (APMgLN) crystals. The APMgLN crystals are designed with different chirp parameters for the DFG process to broaden their thermal acceptance bandwidths to different extents. The idler wavelength tuning of the cascaded OPO is realized by changing the temperature of the designed APMgLN crystal and the cascaded oscillation is achieved in a single pump pass singly resonant linear cavity. The pump-to-idler conversion efficiencies with respect to the pump pulse duration and ratio of OPO coefficient to DFG coefficient are calculated by numerically solving the coupled wave equations. The optimal working conditions of the tunable cascaded OPOs pumped by pulses with energies of 350 μJ and 700 μJ are compared to obtain the general rules of optimization. It is concluded that the optimization becomes the interplay between the ratio of OPO coefficient to DFG coefficient and the pump pulse duration when the idler wavelength tuning range and the pump pulse energy are fixed. Besides, higher pump pulse energy is beneficial for reaching higher optimal pump-to-idler conversion efficiency as long as the APMgLN crystal is optimized according to this pump condition. To the best of our knowledge, this is the first numerical analysis of idler wavelength tunable cascaded OPOs based on chirp-assisted APMgLN crystals. Project supported by the National Natural Science Foundation of China (Grant No. 61505236), the Innovation Program of Shanghai Institute of Technical Physics, China (Grant No. CX-2), and the Program of Shanghai

  16. The Effect of Chain Structures on the Crystallization Behavior and Membrane Formation of Poly(Vinylidene Fluoride) Copolymers

    PubMed Central

    Ma, Wenzhong; Yuan, Haoge; Wang, Xiaolin

    2014-01-01

    The crystallization behaviors of two copolymers of PVDF were studied, and the effect of copolymerized chains on the crystallization behavior was investigated. The results indicated that both copolymers had a lowered crystallization temperature and crystallinity. The crystallization rate was improved by the copolymer with symmetrical units in PVDF chains, but hindered by asymmetrical units, compared with the neat PVDF. The symmetrical units in PVDF chains favored the β-crystals with fiber-like structures. According to the solubility parameter rule, methyl salicylate (MS) can be chosen as a diluent for PVDF copolymers. Both diluted systems had liquid-liquid (L-L) regions in the phase diagrams, which was due to the lowered crystallization temperature. PMID:24957175

  17. Water fluoridation and osteoporotic fracture.

    PubMed

    Hillier, S; Inskip, H; Coggon, D; Cooper, C

    1996-09-01

    Osteoporotic fractures constitute a major public health problem. These fractures typically occur at the hip, spine and distal forearm. Their pathogenesis is heterogeneous, with contributions from both bone strength and trauma. Water fluoridation has been widely proposed for its dental health benefits, but concerns have been raised about the balance of skeletal risks and benefits of this measure. Fluoride has potent effects on bone cell function, bone structure and bone strength. These effects are mediated by the incorporation of fluoride ions in bone crystals to form fluoroapatite, and through an increase in osteoblast activity. It is believed that a minimum serum fluoride level of 100 ng/ml must be achieved before osteoblasts will be stimulated. Serum levels associated with drinking water fluoridated to 1 ppm are usually several times lower than this value, but may reach this threshold at concentrations of 4 ppm in the drinking water. Animal studies suggest no effect of low-level (0-3 ppm) fluoride intake on bone strength, but a possible decrease at higher levels. Sodium fluoride has been used to treat established osteoporosis for nearly 30 years. Recent trials of this agent, prescribed at high doses, have suggested that despite a marked increase in bone mineral density, there is no concomitant reduction in vertebral fracture incidence. Furthermore, the increase in bone density at the lumbar spine may be achieved at the expense of bone mineral in the peripheral cortical skeleton. As a consequence, high dose sodium fluoride (80 mg daily) is not currently used to treat osteoporosis. At lower doses, recent trials have suggested a beneficial effect on both bone density and fracture. The majority of epidemiological evidence regarding the effect of fluoridated drinking water on hip fracture incidence is based on ecological comparisons. Although one Finnish study suggested that hip fracture rates in a town with fluoridated water were lower than those in a matching town

  18. Lithium batteries. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-07-01

    Federally funded research on design, development, components, testing corrosion, electrolytes, sealing, hazards of lithium cells are presented. Batteries studied include lithium organic cells, lithium sulfur cells, lithium water air cells, and lithium nickel fluoride cells. Applications cover use in spacecraft, electric vehicles, off peak energy storage, and forklift trucks. This updated bibliography contains 151 citations, 57 of which are new entries to the previous edition.

  19. Structure, ion transport, and relaxation dynamics of polyethylene oxide/poly (vinylidene fluoride co-hexafluoropropylene)—lithium bis(trifluoromethane sulfonyl) imide blend polymer electrolyte embedded with ionic liquid

    NASA Astrophysics Data System (ADS)

    Das, S.; Ghosh, A.

    2016-03-01

    We have studied structure, ion transport, and relaxation dynamics in polyethylene oxide/poly (vinylidene fluoride-hexafluoropropylene)-lithium bis(trifluoromethane)sulfonimide blend polymer electrolytes embedded with 1-propyl-3-methyleimidazoliuum bis(trifluromethyle-sulfonyl)imide ionic liquid. Structural property and ion-polymer interaction of polymer electrolytes have been studied using X-ray diffraction and Raman spectroscopy. The addition of ionic liquid decreases glass transition temperature and reduces crystalline phase in the polymer matrix. It is also observed that surface becomes smooth with increase of ionic liquid content. The temperature dependence of the Li ion conductivity follows Vogel-Tammann-Fulcher type behaviour when a sufficient amount of ionic liquid is added to polymer matrix. The electric modulus has been studied using Havriliak-Negami function for the understanding of ion dynamics. The modulus data have been analyzed using non-exponential Kohlrausch-Williams-Watts function. It is observed that the non-exponential parameter β is quite lower than unity, suggesting existence of a non-exponential relaxation. The temperature dependence of the relaxation time also follows Vogel-Tammann-Fulcher relation for compositions with higher ionic liquid content.

  20. EPR and ENDOR Studies of Point Defects in Lithium Tetraborate Crystals

    DTIC Science & Technology

    2012-12-14

    Thermoluminescence (TL), photoluminescence (PL), photoluminescence excitation (PLE), and optical absorption (OA) are also used. An intrinsic hole trap associated...with lithium vacancies is characterized with EPR and ENDOR and its thermal stability is determined using thermoluminescence . A “perturbed” hole...Tetraborate…………... 40 3.1. Introduction……………………………………………………………… 40 3.2. Thermoluminescence Results…………………………………………… 41 3.3. Electron Paramagnetic

  1. HEATS OF FORMATION OF THE FLUOBORATES OF LITHIUM, SODIUM AND POTASSIUM.

    DTIC Science & Technology

    FLUOBORATES , *THERMOCHEMISTRY, * LITHIUM COMPOUNDS, *SODIUM COMPOUNDS, *POTASSIUM COMPOUNDS, THERMOCHEMISTRY, THERMOCHEMISTRY, THERMOCHEMISTRY, HEAT OF FORMATION, HEAT OF SOLUTION, FLUORIDES, CALORIMETRY, UNITED KINGDOM.

  2. Functionalization of borate networks by the incorporation of fluoride: Syntheses, crystal structures; and nonlinear optical properties of novel actinide fluoroborates

    SciTech Connect

    Wang, Shuao; Alekseev, Evgeny V.; Diwu, Juan; Miller, Hannah M.; Oliver, Allen G.; Liu, Guokui; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.

    2011-06-14

    The boric acid flux reactions of uranyl nitrate with sodium, potassium, rubidium, or thallium fluoride result in the formation of a novel family of uranyl(VI) fluoroborate materials. These compounds are Na[(UO₂)B₅O₈(OH)F]·H₂O (NaUBOF-1), K[(UO₂)B₅O₈(OH)F] (KUBOF-1), K₁₁[(UO₂)₆B₂₄O₃₆F₂₂)](H₂BO₃) (KUBOF-2), Rb[(UO₂)B₅O₈(OH)F] (RbUBOF-1), and Tl[(UO₂)B₅O₈(OH)F] (TlUBOF-1). A new neptunium(VI) fluoroborate that is isotypic with NaUBOF-1, Na[(NpO₂)B₅O₈(OH)F]·H₂O (NaNpBOF-1), was synthesized via the boric acid flux reaction of neptunium(VI) nitrate with sodium fluoride. These new actinide fluoroborates share a common structural motif consisting of a linear actinyl (U(Np)O₂2+) cation surrounded by BO₃ triangles and BO₄ tetrahedra to create an U(Np)O₈ hexagonal bipyramidal environment around uranium or neptunium. The borate anions bridge between actinyl units to create layers. B–F bonds were formed during the reactions to yield BO₃F tetrahedral units. The BO3F tetrahedra and additional BO₃ triangles extend from the actinyl polyborate layers and are directed approximately perpendicular to the layers. A novel actinyl borate layered topology was found in K₁₁[(UO₂)₆B₂₄O₃₆F₂₂)](H₂BO₃) (KUBOF-2). Except for K[(UO₂)B₅O₈(OH)F] (KUBOF-1) and K₁₁[(UO₂)₆B₂₄O₃₆F₂₂)](H₂BO₃) (KUBOF-2), all of the other actinide fluoroborate phases adopt noncentrosymmetric space groups. Tl[(UO₂)B₅O₈(OH)F] (TlUBOF-1), which can be obtained as a pure phase, displays second-harmonic generation of 532-nm light from 1064-nm light.

  3. Tip-induced domain growth on the non-polar cuts of lithium niobate single-crystals

    SciTech Connect

    Alikin, Denis O.; Ievlev, Anton; Turigin, Anton P.; Lobov, Alexei; Kalinin, Sergei V; Shur, Vladimir Ya.

    2015-05-05

    Currently ferroelectric materials with designed domain structures are considered as a perspective material for new generation of photonic, data storage and data processing devices. Application of external electric field is the most convenient way of the domain structure formation. Lots of papers are devoted to investigation of the domain kinetics on polar surface of crystals while the forward growth remains one of the most mysterious stages due to lack of experimental methods allowing to study it. Here we performed tip-induced polarization reversal on X- and Y-non-polar cuts in single-crystal of congruent lithium niobate allows us to study the forward growth with high spatial resolution. The revealed difference in the shape and length of domains induced on X- and Y-cuts is beyond previously developed theoretical approaches used for the theoretical consideration of the domains growth at non-polar ferroelectric surfaces. Lastly, to explain experimental results we used kinetic approach with anisotropy of screening efficiency along different crystallographic directions.

  4. Tip-induced domain growth on the non-polar cuts of lithium niobate single-crystals

    DOE PAGES

    Alikin, Denis O.; Ievlev, Anton; Turigin, Anton P.; ...

    2015-05-05

    Currently ferroelectric materials with designed domain structures are considered as a perspective material for new generation of photonic, data storage and data processing devices. Application of external electric field is the most convenient way of the domain structure formation. Lots of papers are devoted to investigation of the domain kinetics on polar surface of crystals while the forward growth remains one of the most mysterious stages due to lack of experimental methods allowing to study it. Here we performed tip-induced polarization reversal on X- and Y-non-polar cuts in single-crystal of congruent lithium niobate allows us to study the forward growthmore » with high spatial resolution. The revealed difference in the shape and length of domains induced on X- and Y-cuts is beyond previously developed theoretical approaches used for the theoretical consideration of the domains growth at non-polar ferroelectric surfaces. Lastly, to explain experimental results we used kinetic approach with anisotropy of screening efficiency along different crystallographic directions.« less

  5. 127I NQR and spectroscopic investigation of impurity-doped and mixed lithium iodate Li 1- xH xIO 3 crystals

    NASA Astrophysics Data System (ADS)

    Barabash, A.; Gavrilko, T.; Eshimov, K.; Baran, J.; Ratajczak, H.

    2004-12-01

    The 127I NQR, IR absorption and Raman spectra of impurity-doped and mixed lithium iodate Li 1- xH xIO 3 crystals grown from water solutions with different LiIO 3/HIO 3 ratios were investigated depending on the content of the impurity hydrogen x. The NQR results suggested that, at small concentration of doping iodic acid x<0.22, the lattice dynamics of the crystal grown from water solution changes significantly though the crystal retains hexagonal symmetry. Spectroscopic studies are compatible with average hexagonal symmetry of the grown doped crystals. From the results of Raman studies at room temperature and 100 K, the concentration range of hydrogen dopant 0.22< x<0.36 was found where disordered solid solution crystals Li 1- xH xIO 3 are formed.

  6. Periodic domain inversion in x-cut single-crystal lithium niobate thin film

    NASA Astrophysics Data System (ADS)

    Mackwitz, P.; Rüsing, M.; Berth, G.; Widhalm, A.; Müller, K.; Zrenner, A.

    2016-04-01

    We report the fabrication of periodically poled domain patterns in x-cut lithium niobate thin-film. Here, thin films on insulator have drawn particular attention due to their intrinsic waveguiding properties offering high mode confinement and smaller devices compared to in-diffused waveguides in bulk material. In contrast to z-cut thin film lithium niobate, the x-cut geometry does not require back electrodes for poling. Further, the x-cut geometry grants direct access to the largest nonlinear and electro-optical tensor element, which overall promises smaller devices. The domain inversion was realized via electric field poling utilizing deposited aluminum top electrodes on a stack of LN thin film/SiO2 layer/Bulk LN, which were patterned by optical lithography. The periodic domain inversion was verified by non-invasive confocal second harmonic microscopy. Our results show domain patterns in accordance to the electrode mask layout. The second harmonic signatures can be interpreted in terms of spatially, overlapping domain filaments which start their growth on the +z side.

  7. Growth of hollow nickel fluoride whiskers

    SciTech Connect

    Petrov, S. V.; Orekhov, Yu. F.; Fedorov, P. P.

    2009-07-15

    Hollow nickel fluoride whiskers have been obtained by condensation from the vapor phase onto a platinum substrate in a flow of hydrogen fluoride. Crystals up to 5 mm in length have a square cross section with a 300 {+-} 30-{mu}m side. The wall thickness is 85 {+-} 20 {mu}m.

  8. Molecular packing and magnetic properties of lithium naphthalocyanine crystals: hollow channels enabling permeability and paramagnetic sensitivity to molecular oxygen

    PubMed Central

    Pandian, Ramasamy P.; Dolgos, Michelle; Marginean, Camelia; Woodward, Patrick M.; Hammel, P. Chris; Manoharan, Periakaruppan T.; Kuppusamy, Periannan

    2009-01-01

    The synthesis, structural framework, magnetic and oxygen-sensing properties of a lithium naphthalocyanine (LiNc) radical probe are presented. LiNc was synthesized in the form of a microcrystalline powder using a chemical method and characterized by electron paramagnetic resonance (EPR) spectroscopy, magnetic susceptibility, powder X-ray diffraction analysis, and mass spectrometry. X-Ray powder diffraction studies revealed a structural framework that possesses long, hollow channels running parallel to the packing direction. The channels measured approximately 5.0 × 5.4 Å2 in the two-dimensional plane perpendicular to the length of the channel, enabling diffusion of oxygen molecules (2.9 × 3.9 Å2) through the channel. The powdered LiNc exhibited a single, sharp EPR line under anoxic conditions, with a peak-to-peak linewidth of 630 mG at room temperature. The linewidth was sensitive to surrounding molecular oxygen, showing a linear increase in pO2 with an oxygen sensitivity of 31.2 mG per mmHg. The LiNc microcrystals can be further prepared as nano-sized crystals without the loss of its high oxygen-sensing properties. The thermal variation of the magnetic properties of LiNc, such as the EPR linewidth, EPR intensity and magnetic susceptibility revealed the existence of two different temperature regimes of magnetic coupling and hence differing columnar packing, both being one-dimensional antiferromagnetic chains but with differing magnitudes of exchange coupling constants. At a temperature of ∼50 K, LiNc crystals undergo a reversible phase transition. The high degree of oxygen-sensitivity of micro- and nano-sized crystals of LiNc, combined with excellent stability, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy. PMID:19809598

  9. A study of the piezoelectric resonance in metal organic NLO single crystals: Sodium D-isoascorbate monohydrate and Lithium L-ascorbate dihydrate

    NASA Astrophysics Data System (ADS)

    Saripalli, Ravi Kiran; Raghavendra Rao, K.; Sanath Kumar, R.; Bhat, H. L.; Elizabeth, Suja

    2016-05-01

    Large single crystals of Sodium D-isoacsorbate monohydrate and Lithium L-ascorbate dehydrate were grown using solution growth technique. Dielectric constant and dielectric loss were monitored as a function of frequency at different temperatures. These are typically characterized by strong resonance peaks. The piezoelectric coefficients d31, elastic coefficient (S11) and electromechanical coupling coefficient (k31) were estimated by resonance-antiresonance method. The temperature dependence of the resonance-peaks frequencies was studied.

  10. Photorefractive effect in iron-doped lithium niobate crystals induced by femtosecond pulses of 1.5 {mu}m wavelength

    SciTech Connect

    Beyer, O.; Breunig, I.; Kalkum, F.; Buse, K.

    2006-01-30

    Illumination of iron-doped lithium crystals (LiNbO{sub 3}:Fe) with femtosecond pulses of 1.5 {mu}m wavelength results in large refractive index changes {delta}n in the order of 10{sup -3}. The sign of the refractive index changes depends on the polarization of the recording light. The results can be very useful for fabrication of tailored holographic components for telecommunication.

  11. Electrical conductivity of MgO crystals implanted with lithium ions

    NASA Astrophysics Data System (ADS)

    Tardío, M.; Ramírez, R.; González, R.; Chen, Y.; Alves, E.

    2002-05-01

    MgO single crystals were implanted with a fluence of 1×10 17 Li +/cm 2 with 175 keV. Using ac and dc techniques, the electrical conductivity of these crystals was investigated in the temperature range 296-440 K. The electrical conductivity of the implanted region was 14 orders of magnitude higher than the unimplanted area. Measurements at different temperatures suggest a thermally activated process with an activation energy of about 0.33 eV. In the implanted area, electrical contacts are found to be ohmic whereas contacts are blocking in unimplanted crystals. Removal of thin layers of the implanted region by immersing the crystal in hot phosphoric acid suggests that the enhancement in conductivity in the implanted region is associated with the intrinsic defects created by the implantation, rather than with the Li ions.

  12. Combining piracetam and lithium salts: ionic co-crystals and co-drugs?

    PubMed

    Braga, Dario; Grepioni, Fabrizia; Maini, Lucia; Capucci, Davide; Nanna, Saverio; Wouters, Johan; Aerts, Luc; Quéré, Luc

    2012-08-25

    Mechanochemical reaction of solid piracetam with the inorganic salts LiCl and LiBr yields ionic co-crystals which are also co-drugs, characterized by markedly different thermal properties with respect to pure components, also depending on the method for preparation and/or conditions of measurements; single crystal and powder X-ray diffraction at variable temperatures, DSC, TGA, hot stage microscopy (HSM) and intrinsic dissolution rate have been used to fully characterize the solid products.

  13. Photonic Crystal Fabrication in Lithium Nobate via Pattern Transfer Through Wet and Dry Etched Chromium Mask

    DTIC Science & Technology

    2012-10-02

    sizes is important to the development of optoelectronic devices. This paper reports a fabrication process to dry etch X -cut LN at a submicron scale using...mission of light depending on the desired application. Production of photonic crystals in X -cut LN requires efficient and reliable fabrication...deposition of LiF during the etching process.7,8 In fabrication of dry-etched LN photonic crystals, the fab - rication methods can be summarized as the

  14. Deformation, Stress Relaxation, and Crystallization of Lithium Silicate Glass Fibers Below the Glass Transition Temperature

    NASA Technical Reports Server (NTRS)

    Ray, Chandra S.; Brow, Richard K.; Kim, Cheol W.; Reis, Signo T.

    2004-01-01

    The deformation and crystallization of Li(sub 2)O (center dot) 2SiO2 and Li(sub 2)O (center dot) 1.6SiO2 glass fibers subjected to a bending stress were measured as a function of time over the temperature range -50 to -150 C below the glass transition temperature (Tg). The glass fibers can be permanently deformed at temperatures about 100 C below T (sub)g, and they crystallize significantly at temperatures close to, but below T,, about 150 C lower than the onset temperature for crystallization for these glasses in the no-stress condition. The crystallization was found to occur only on the surface of the glass fibers with no detectable difference in the extent of crystallization in tensile and compressive stress regions. The relaxation mechanism for fiber deformation can be best described by a stretched exponential (Kohlrausch-Williams-Watt (KWW) approximation), rather than a single exponential model.The activation energy for stress relaxation, Es, for the glass fibers ranges between 175 and 195 kJ/mol, which is considerably smaller than the activation energy for viscous flow, E, (about 400 kJ/mol) near T, for these glasses at normal, stress-free condition. It is suspected that a viscosity relaxation mechanism could be responsible for permanent deformation and crystallization of the glass fibers below T,

  15. Photoreduction of metal nanostructures on periodically proton exchanged MgO-doped lithium niobate crystals

    SciTech Connect

    Balobaid, Laila; Craig Carville, N.; Collins, Liam; Rodriguez, Brian J.; Manzo, Michele; Gallo, Katia

    2013-10-28

    Local reactivity on periodically proton exchanged lithium niobate (PPE:LN) surfaces is a promising route for the fabrication of regularly spaced nanostructures. Here, using MgO-doped PPE:LN templates, we investigate the influence of the doping on the nanostructure formation as a function of the proton exchange (PE) depth. The deposition is found to occur preferentially along the boundary between MgO-doped LN and the PE region when the PE depth is at least 1.73 μm, however, for shallower depths, deposition occurs across the entire PE region. The results are found to be consistent with an increased photoconductivity of the MgO-doped LN.

  16. Theoretical exploration of various lithium peroxide crystal structures in a Li-air battery

    SciTech Connect

    Lau, Kah; Qiu, Dantong; Luo, Xiangyi; Greeley, Jeffrey; Curtiss, Larry; Lu, Jun; Amine, Khalil

    2015-01-14

    We describe a series of metastable Li₂O₂ crystal structures involving different orientations and displacements of the O₂²⁻ peroxy ions based on the known Li₂O₂ crystal structure. Within the vicinity of the chemical potential ΔG ~ 0.20 eV/Li from the thermodynamic ground state of the Li₂O₂ crystal structure (i.e., Föppl structure), all of these newly found metastable Li₂O₂ crystal structures are found to be insulating and high-k materials, and they have a common unique signature of an O₂²⁻ O-O vibration mode (ω ~ 799–865 cm⁻¹), which is in the range of that commonly observed in Li-air battery experiments, regardless of the random O₂²⁻ orientations and the symmetry in the crystal lattice. From XRD patterns analysis, the commercially available Li₂O₂ powder is confirmed to be the thermodynamic ground state Föppl-like structure. However, for Li₂O₂ compounds that are grown electrochemically under the environment of Li-O₂ cells, we found that the XRD patterns alone are not sufficient for structural identification of these metastable Li₂O₂ crystalline phases due to the poor crystallinity of the sample. In addition, the commonly known Raman signal of O₂²⁻ vibration mode is also found to be insufficient to validate the possible existence of these newly predicted Li₂O₂ crystal structures, as all of them similarly share the similar O₂²⁻ vibration mode. However considering that the discharge voltage in most Li-O₂ cells are typically several tenths of an eV below the thermodynamic equilibrium for the formation of ground state Föppl structure, the formation of these metastable Li₂O₂ crystal structures appears to be thermodynamically feasible.

  17. Theoretical exploration of various lithium peroxide crystal structures in a Li-air battery

    DOE PAGES

    Lau, Kah; Qiu, Dantong; Luo, Xiangyi; ...

    2015-01-14

    We describe a series of metastable Li₂O₂ crystal structures involving different orientations and displacements of the O₂²⁻ peroxy ions based on the known Li₂O₂ crystal structure. Within the vicinity of the chemical potential ΔG ~ 0.20 eV/Li from the thermodynamic ground state of the Li₂O₂ crystal structure (i.e., Föppl structure), all of these newly found metastable Li₂O₂ crystal structures are found to be insulating and high-k materials, and they have a common unique signature of an O₂²⁻ O-O vibration mode (ω ~ 799–865 cm⁻¹), which is in the range of that commonly observed in Li-air battery experiments, regardless of themore » random O₂²⁻ orientations and the symmetry in the crystal lattice. From XRD patterns analysis, the commercially available Li₂O₂ powder is confirmed to be the thermodynamic ground state Föppl-like structure. However, for Li₂O₂ compounds that are grown electrochemically under the environment of Li-O₂ cells, we found that the XRD patterns alone are not sufficient for structural identification of these metastable Li₂O₂ crystalline phases due to the poor crystallinity of the sample. In addition, the commonly known Raman signal of O₂²⁻ vibration mode is also found to be insufficient to validate the possible existence of these newly predicted Li₂O₂ crystal structures, as all of them similarly share the similar O₂²⁻ vibration mode. However considering that the discharge voltage in most Li-O₂ cells are typically several tenths of an eV below the thermodynamic equilibrium for the formation of ground state Föppl structure, the formation of these metastable Li₂O₂ crystal structures appears to be thermodynamically feasible.« less

  18. On the strain-induced structural evolution upon uniaxial stretching of Poly(VinyliDene Fluoride): influence of secondary crystals and crystalline relaxation

    NASA Astrophysics Data System (ADS)

    Defebvin, Juliette; Barrau, Sophie; Stoclet, Grégory; Lefebvre, Jean-Marc; Polymer Engineering Science Team

    2015-03-01

    Development of more efficient piezoelectric devices tends to innovate and create materials able to combine flexibility and electro-mechanical conversion. Poly(vinylidene fluoride) (PVDF) is a semi-crystalline polymer that exhibits interesting piezoelectric properties. Besides PVDF is able to convert a mechanical solicitation into an electric energy and vice versa. However these physical properties are highly dependent on the polymer crystal structure. PVDF presents at least two main crystalline forms. The most common phase is the α-phase that is non-polar. On the other hand, the β phase is the most polar one and it can be obtained by a stretching of the α-phase. Knowing the influence of the drawing conditions on the strain-induced structural evolution is thus of prime interest. To assess this point the strain-induced structural evolution of PVDF, stretched under different conditions, has been followed in-situ by means of WAXS/SAXS experiments. As a main result, this study shows that drawing conditions strongly affect both the α to β phase conversion degree and the crystalline morphology. Moreover the key role played by the crystalline relaxation of PVDF on the strain-induced structural evolution is also highlighted for the first time.

  19. Crystal field disorder effects in the optical spectra of Nd{sup 3+} and Yb{sup 3+}-doped calcium lithium niobium gallium garnets laser crystals and ceramics

    SciTech Connect

    Lupei, V.; Lupei, A.; Gheorghe, C.; Gheorghe, L.; Achim, A.; Ikesue, A.

    2012-09-15

    The optical spectroscopic properties of RE{sup 3+} (Nd, 1 at. % or Yb, 1 to 10 at. %)-doped calcium-lithium-niobium-gallium garnet (CLNGG) single crystals and ceramics in the 10 K-300 K range are analyzed. In these compositionally disordered materials, RE{sup 3+} substitute Ca{sup 2+} in dodecahedral sites and the charge compensation is accomplished by adjusting the proportion of Li{sup +}, Nb{sup 5+}, and Ga{sup 3+} to the doping concentration. The crystals and ceramics show similar optical spectra, with broad and structured (especially at low temperatures) bands whose shape depends on temperature and doping concentration. At 10 K, the Nd{sup 3+4}I{sub 9/2}{yields}{sup 4}F{sub 3/2,5/2} and Yb{sup 3+2}F{sub 7/2}{yields}{sup 2}F{sub 5/2} absorption bands, which show prospect for diode laser pumping, can be decomposed in several lines that can be attributed to centers with large differences in the crystal field. The positions of these components are the same, but the relative intensity depends on the doping concentration and two main centers dominate the spectra. Non-selective excitation evidences broad emission bands, of prospect for short-pulse laser emission, whereas the selective excitation reveals the particular emission spectra of the various centers. The modeling reveals that the nonequivalent centers correspond to RE{sup 3+} ions with different cationic combinations in the nearest octahedral and tetrahedral coordination spheres, and the most abundant two centers have 4Nb and, respectively, 3Nb1Li in the nearest octahedral sphere. At 300 K, the spectral resolution is lost. It is then inferred that the observed optical bands are envelopes of the spectra of various structural centers, whose resolution is determined by the relative contribution of the temperature-dependent homogeneous broadening and the effects of crystal field disordering (multicenter structure, inhomogeneous broadening). The relevance of spectroscopic properties for selection of pumping

  20. MAS-NMR investigations of the crystallization behaviour of lithium aluminum silicate (LAS) glasses containing P 2O 5 and TiO 2 nucleants

    NASA Astrophysics Data System (ADS)

    Ananthanarayanan, A.; Kothiyal, G. P.; Montagne, L.; Revel, B.

    2010-06-01

    Lithium aluminum silicate (LAS) glass of composition (mol%) 20.4Li 2O-4.0Al 2O 3-68.6SiO 2-3.0K 2O-2.6B 2O 3-0.5P 2O 5-0.9TiO 2 was prepared by melt quenching. The glass was then nucleated and crystallized based on differential thermal analysis (DTA) data and was characterized by 29Si, 31P, 11B and 27Al MAS-NMR. XRD and 29Si NMR showed that lithium metasilicate (Li 2SiO 3) is the first phase to c form followed by cristobalite (SiO 2) and lithium disilicate (Li 2Si 2O 5). 29Si MAS-NMR revealed a change in the network structure already for the glasses nucleated at 550 °C. Since crystalline Li 3PO 4, as observed by 31P MAS-NMR, forms concurrently with the silicate phases, we conclude that crystalline Li 3PO 4 does not act as a nucleating agent for lithium silicate phases. Moreover, 31P NMR indicates the formation of M-PO 4 ( M=B, Al or Ti) complexes. The presence of BO 3 and BO 4 structural units in all the glass/glass-ceramic samples is revealed through 11B MAS-NMR. B remains in the residual glass and the crystallization of silicate phases causes a reduction in the number of alkali ions available for charge compensation. As a result, the number of trigonally coordinated B (BO 3) increases at the expense of tetrahedrally coordinated B (BO 4). The 27Al MAS-NMR spectra indicate the presence of tetrahedrally coordinated Al species, which are only slightly perturbed by the crystallization.

  1. Development of dye-sensitized solar cells composed of liquid crystal embedded, electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers as polymer gel electrolytes.

    PubMed

    Ahn, Sung Kwang; Ban, Taewon; Sakthivel, P; Lee, Jae Wook; Gal, Yeong-Soon; Lee, Jin-Kook; Kim, Mi-Ra; Jin, Sung-Ho

    2012-04-01

    In order to overcome the problems associated with the use of liquid electrolytes in dye-sensitized solar cells (DSSCs), a new system composed of liquid crystal embedded, polymer electrolytes has been developed. For this purpose, three types of DSSCs have been fabricated. The cells contain electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVdF-co-HFP) polymer gel electrolyte, with and without doping with the liquid crystal E7 and with a liquid electrolyte. The morphologies of the newly prepared DSSCs were explored using field emission scanning electron microscopy (FE-SEM). Analysis of the FE-SEM images indicate that the DSSC composed of E7 embedded on e-PVdF-co-HFP polymer gel electrolyte has a greatly regular morphology with an average diameter. The ionic conductivity of E7 embedded on e-PVdF-co-HFP polymer gel electrolyte was found to be 2.9 × 10(-3) S/cm at room temperature, a value that is 37% higher than that of e-PVdF-co-HFP polymer gel electrolyte. The DCCS containing the E7 embedded, e-PVdF-co-HFP polymer gel electrolyte was observed to possess a much higher power conversion efficiency (PCE = 6.82%) than that of an e-PVdF-co-HFP nanofiber (6.35%). In addition, DSSCs parameters of the E7 embedded, e-PVdF-co-HFP polymer gel electrolyte (V(oc) = 0.72 V, J(sc) = 14.62 mA/cm(2), FF = 64.8%, and PCE = 6.82% at 1 sun intensity) are comparable to those of a liquid electrolyte (V(oc) = 0.75 V, J(sc) = 14.71 mA/cm(2), FF = 64.9%, and PCE = 7.17%, both at a 1 sun intensity).

  2. Piezoelectric and ferroelectric properties of lead-free niobium-rich potassium lithium tantalate niobate single crystals

    SciTech Connect

    Li, Jun; Li, Yang; Zhou, Zhongxiang; Guo, Ruyan; Bhalla, Amar S.

    2014-01-01

    Graphical abstract: - Highlights: • Lead-free K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} single crystals were grown using the top-seeded melt growth method. • The piezoelectric and ferroelectric properties of as-grown crystals were systematically investigated. • The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N. • The coercive fields of P–E hysteresis loops are quite small, about or less than 1 kV/mm. - Abstract: Lead-free potassium lithium tantalate niobate single crystals with the composition of K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} (abbreviated as KLTN, x = 0.51, 0.60, 0.69, 0.78) were grown using the top-seeded melt growth method. Their piezoelectric and ferroelectric properties in as-grown crystals have been systematically investigated. The phase transitions and Curie temperatures were determined from dielectric and pyroelectric measurements. Piezoelectric coefficients and electromechanical coupling factors in thickness mode, length-extensional mode and longitudinal mode were obtained. The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N are comparable to the lead-based PZT composition. The polarization versus electric field hysteresis loops show saturated shapes. In short, lead-free niobium-rich KLTN system possesses comparable properties to those in important lead-based piezoelectric material nowadays.

  3. Lithium-bearing fluor-arfvedsonite from Hurricane Mountain, New Hampshire: A crystal-chemical study

    USGS Publications Warehouse

    Hawthorne, F.C.; Oberti, R.; Ottolini, L.; Foord, E.E.

    1996-01-01

    The structures of two crystals of Li-bearing fluor-arfvedsonite (1) (K0.32Na0.68)Na2(Li0.48Fe 2+2.83Mn2+0.10Zn 0.06Fe3+1.46Ti0.07) (Si7.88Al0.12)O22[Fu1.15(OH) 0.85] and (2) (K0.25Na0.75)Na2(Li0.48Fe 2+2.84Mn2+0.11Zn 0.05Fe3+1.45Ti0.07)(Si 7.89Al0.11)O22[F1.35(OH) 0.65] from a granitic pegmatite, Hurricane Mountain, New Hampshire, have been refined to R indices of 1.5(1.6)% based on 1380(1387) reflections measured with MoK?? X-radiation. The unit cell parameters are (1) a 9.838(4), b 17.991(6), c 5.315(2) A??, 103.78(3)??, V 913.7 A??3 and (2) a 9.832(3), b 17.990(7), c 5.316(3) A??, ?? 103.79(3)??, V 913.2 A??3. Site-scattering refinement shows Li to be completely ordered at the M(3) site in these crystals. The amphibole composition is intermediate between fluor-arfvedsonite and fluor-ferro-leakeite with a small component (???10%) of fluor-ferro-ferri-nybo??ite. These amphibole crystals project into miarolitic cavities in a pegmatitic phase of a riebeckite granite. The early-crystallizing amphibole is close to fluor-ferro-leakeite in composition, but becomes progressively depleted in Li and F as crystals project out into miarolitic cavities; the final amphibole to crystallize is a fibrous Li-poor riebeckite. Li plays a significant role in late-stage fractionation involving the crystallization of alkali amphibole in peralkaline granitic environments.

  4. Photoselective Vaporesection of the Prostate with an End-firing Lithium Triborate Crystal Laser

    PubMed Central

    Wang, Xin; Liu, Ming; Zhang, Yao-Guang; Zhu, Sheng-Cai; Wan, Ben; Wang, Jian-Ye

    2017-01-01

    Background: Photoselective vaporization of the prostate is a technique that is widely used for the treatment of benign prostatic hyperplasia (BPH) and has pronounced advantages compared to the traditional transurethral resection of the prostate. Following the recent introduction of end-firing lithium triborate lasers, we have created a new technique called photoselective vaporesection of the prostate (PVRP). This study described our initial experience using the PVRP technique for the treatment of BPH. Methods: This prospective study included a total of 35 patients with BPH who underwent PVRP from August 2013 to July 2014. The chief clinical parameters were obtained and evaluated during the perioperative period and follow-up, including the International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum urinary flow rate, and prostate volume. All variables were evaluated for statistically significant differences compared to baseline values using the analysis of variance. Results: The mean subgroup IPSS and QoL scores significantly improved during follow-up; the respective decreases in IPSS storage score, IPSS voiding score, IPSS nocturia score, and QoL score were 75.3%, 83.6%, 51.4%, and 71.7%, respectively (all P < 0.001 compared with baseline). Three patients were diagnosed with prostate cancer based on postoperative pathological examinations. There were no serious perioperative complications. Conclusion: The PVRP technique demonstrates satisfactory short-term clinical outcomes and perioperative safety in the treatment of BPH. PMID:28303843

  5. Controlled parallel crystallization of lithium disilicate and diopside using a combination of internal and surface nucleation

    NASA Astrophysics Data System (ADS)

    Rampf, Markus; Dittmer, Marc; Ritzberger, Christian; Höland, Wolfram

    2016-10-01

    In the mid-19th century, Dr. Donald Stookey identified the importance and usability of nucleating agents and mechanisms for the development of glass-ceramic materials. Today, a number of various internal and surface mechanisms as well as combinations thereof have been established in the production of glass-ceramic materials. In order to create new innovative material properties the present study focuses on the precipitation of CaMgSiO6 as a minor phase in Li2Si2O5 based glass-ceramics. In the base glass of the SiO2-Li2O-P2O5-Al2O3-K2O-MgO-CaO system P2O5 serves as nucleating agent for the internal precipitation of Li2Si2O5 crystals while a mechanical activation of the glass surface by means of ball milling is necessary to nucleate the minor CaMgSi2O6 crystal phase. For a successful precipitation of CaMgSi2O6 a minimum ratio of MgO and CaO in the range between 1.4 mol% and 2.9 mol% in the base glasses was determined. The nucleation and crystallization of both crystal phases takes place during sintering a powder compact. Dependent on the quality of the sintering process the dense Li2Si2O5-CaMgSi2O6 glass-ceramics show a mean biaxial strength of up to 392 ± 98 MPa. The microstructure of the glass-ceramics is formed by large (5-10 µm) bar like CaMgSi2O6 crystals randomly embedded in a matrix of small (≤ 0.5 µm) plate like Li2Si2O5 crystals arranged in an interlocking manner. While there is no significant influence of the minor CaMgSi2O6 phase on the strength of the material, the translucency of the material decreases upon precipitation of the minor phase.

  6. Nucleation and Crystallization as Induced by Bending Stress in Lithium Silicate Glass Fibers

    NASA Technical Reports Server (NTRS)

    Reis, Signo T.; Kim, Cheol W.; Brow, Richard K.; Ray, Chandra S.

    2003-01-01

    Glass Fibers of Li2O.2SiO2 (LS2) and Li2O.1.6SiO2 (LS1.6) compositions were heated near, but below, the glass transition temperature for different times while subjected to a constant bending stress of about 1.2 GPa. The nucleation density and the crystallization tendency estimated by differential thermal analysis (DTA) of a glass sample in the vicinity of the maximum of the bending stress increased relative to that of stress-free glass fibers. LS2 glass fibers were found more resistant to nucleation and crystallization than the Ls1.6 glass fibers. These results are discussed in regards to shear thinning effects on glass stability.

  7. Electro-optic properties of indium/erbium-codoped lithium niobate crystal for integrated optics

    NASA Astrophysics Data System (ADS)

    Du, Wan-Ying; Zhang, Zi-Bo; Ren, Shuai; Wong, Wing-Han; Yu, Dao-Yin; Pun, Edwin Yue-Bun; Zhang, De-Long

    2017-02-01

    Clamped and unclamped electro-optic coefficients γ13 and γ33 of In3+/Er3+-codoped LiNbO3 crystals, which were grown by Czochralski method from the melts containing 0.5 mol% Er2O3 while varied In2O3 contents of 0.0, 0.5, 1.0 and 1.5 mol%, were measured by Mach-Zehnder interferometry. The results show that In3+/Er3+ codoping does not cause change of γ13 and γ33, and both γ13 and γ33 can be regarded as unchanged in the studied In3+ concentration range of 0-2.6 mol% (in crystal) within the experimental error of 3%. The small doping effect is desired in light of the electro-optic application of the crystal. A qualitative, comprehensible explanation for the small effect is given on the basis of the EO coefficient model of LiNbO3 and doping effect on the defect structure of LiNbO3.

  8. Theoretical study of Ti0 and Pb+ centers in alkali halide and alkaline earth fluoride type crystals

    NASA Astrophysics Data System (ADS)

    Andriessen, J.; Postma, H.

    1987-04-01

    A theoretical study has been carried out on the hfi of Pb+ defects in KCl, CaF2 and BaF2 using an earlier developed crystal field model. Experimental results can be explained in the same way as was done for Tl0 in KCl. However some parameters seem to have a less physical meaning than in the case of Tl0. A new method is in progress using the ASW band structure procedure in order to estimate genuine solid state effects. Preliminary results are encouraging.

  9. Study of structural and ferromagnetic resonance properties of spinel lithium ferrite (LiFe{sub 5}O{sub 8}) single crystals

    SciTech Connect

    Pachauri, Neha; Khodadadi, Behrouz; Mewes, Tim; Althammer, Matthias; Singh, Amit V.; Gupta, Arunava; Loukya, B.; Datta, Ranjan; Iliev, Milko; Bezmaternykh, Leonard; Gudim, Irina

    2015-06-21

    The effect of B-site cation ordering on the room temperature structural and ferromagnetic resonance (FMR) properties of single crystal spinel lithium ferrite (LiFe{sub 5}O{sub 8}, LFO) have been investigated. A detailed microstructural analysis is done through X-ray diffraction, polarized Raman spectroscopy, and transmission electron microscopy (TEM) to examine the effect of post-annealing on the B-site cation ordering. The X-ray diffraction pattern of the as-grown crystal indicates a disordered state of the crystal. However, the annealed sample shows additional superlattice reflections corresponding to the ordered phase. This ordering is further confirmed by Raman spectra and TEM images, which reveal ordering of Li and Fe ions at the octahedral sites contrasting with the relatively high degree of octahedral site disorder in the as-grown crystal. To study the effect of B-site ordering on the magnetic properties and FMR linewidth, vibrating sample magnetometry and broadband FMR measurements have been performed for both the ordered and disordered phases of lithium ferrite. The value of saturation magnetization for both phases is ∼290 emu/cm{sup 3}. A single mode FMR profile is observed for both phases with little distortion. The linewidth characteristics of the ordered and disordered phases of lithium ferrite phases are compared, and it is observed that the linewidth is independent of the cation ordering. Both the phases exhibit a low linewidth (∼26 Oe at 30 GHz) and the effective damping parameter for the as-grown and annealed samples is determined to be 0.0021 ± 0.0001.

  10. The missing hydrate AlF3·6H2Odbnd [Al(H2O)6]F3: Ionothermal synthesis, crystal structure and characterization of aluminum fluoride hexahydrate

    NASA Astrophysics Data System (ADS)

    Wang, Guangmei; Mudring, Anja-Verena

    2016-11-01

    AlF3 is a strong Lewis acid and several hydrates of it are known, namely the monohydrate, the trihydrate (of which two polymorphs have been described) and the nonohydrate, which forms in the abundance of water, as well as a more complex fluoride of composition Al0.82□0.18F2.46(H2O)0.54 whose structure has been related to the ReO3 type. The monohydrate features edge connected [AlF6] octahedra, in the tri- and nonahydrate mixed F/O coordination of aluminum is observed. Here we report on a new aluminium fluoride hydrate, AlF3·6H2O, which could be obtained via ionothermal synthesis in the ionic liquid n-hexyl-pyridinium tetrafluoroborate. The ionic liquid serves in the synthesis of AlF3·6H2O as the reaction partner (fluoride source) and solvent. Overmore it controls the water activity allowing access to the missing AlF3·6H2O. Single-crystal X-ray diffraction analysis of AlF3·6H2O shows that it crystallizes in the anti-Li3Bi-type of structure according to F3[Al(H2O)6] (Fm-3m, a = 893.1(2) pm, Z = 4) featuring hexaaqua aluminium(III) cations and isolated fluoride anions. The compound was further characterized by powder X-ray diffraction, TG/DTA, IR analyses.

  11. Frequency non-degenerate sequential excitation of the impurity trapped exciton in strontium fluoride crystals doped with ytterbium

    NASA Astrophysics Data System (ADS)

    Senanayake, Pubudu S.; Wells, Jon-Paul R.; Reid, Michael F.; Hughes-Currie, Rosa B.; Berden, Giel; Reeves, Roger J.; Meijerink, Andries

    2015-04-01

    We model the dynamic behaviour observed for impurity-trapped excitons in SrF2:Yb2+ using transient photoluminescence enhancement induced via a two-frequency, sequential excitation process employing an UV optical parametric amplifier synchronized to an IR free electron laser (FEL). We observe sharp transitions interpreted as a change of state of the localized hole and broad bands interpreted as a change of state of the delocalized electron. Our modeling indicates that the 4f crystal-field interaction is 25% smaller than in CaF2. The photoluminescence enhancement transients are analyzed across a range of excitation frequencies using a system of rate equations. The temporal behavior is explained in terms of intra-excitonic relaxation, local lattice heating by the FEL, and liberation of electrons from trap states.

  12. Investigation of Nd3+ ions spectroscopic and laser properties in SrF2 fluoride single crystal

    NASA Astrophysics Data System (ADS)

    Alimov, O. K.; Basiev, T. T.; Doroshenko, M. E.; Fedorov, P. P.; Konyushkin, V. A.; Nakladov, A. N.; Osiko, V. V.

    2012-03-01

    The laser properties of SrF2:Nd3+ crystal with neodymium ions concentration of 0.5 at.% were investigated under diode laser pumping. Using temperature tuning of laser diode pumping wavelength two different lines centered at about 1037 nm and 1044 nm attributed to oscillation of different optical centers were obtained. The maximum lasing slope efficiency of 37% was obtained. The absorption and fluorescence spectra of different individual and clustered Nd3+ ions optical centers were observed depending on Nd3+ concentration. The lifetimes of the high symmetry L-centers were measured and found to be two orders of magnitude longer than that for clustered M-centers at room temperature. The lifetimes of M-centers at different temperatures were measured and microparameter of ion-ion interaction in Nd-pairs was determined.

  13. Frequency non-degenerate sequential excitation of the impurity trapped exciton in strontium fluoride crystals doped with ytterbium

    SciTech Connect

    Senanayake, Pubudu S.; Hughes-Currie, Rosa B.; Wells, Jon-Paul R.; Reid, Michael F.; Berden, Giel; Reeves, Roger J.; Meijerink, Andries

    2015-04-07

    We model the dynamic behaviour observed for impurity-trapped excitons in SrF{sub 2}:Yb{sup 2+} using transient photoluminescence enhancement induced via a two-frequency, sequential excitation process employing an UV optical parametric amplifier synchronized to an IR free electron laser (FEL). We observe sharp transitions interpreted as a change of state of the localized hole and broad bands interpreted as a change of state of the delocalized electron. Our modeling indicates that the 4f crystal-field interaction is 25% smaller than in CaF{sub 2}. The photoluminescence enhancement transients are analyzed across a range of excitation frequencies using a system of rate equations. The temporal behavior is explained in terms of intra-excitonic relaxation, local lattice heating by the FEL, and liberation of electrons from trap states.

  14. Graphite Fluoride Fiber Composites For Heat Sinking

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh; Long, Martin; Stahl, Mark

    1989-01-01

    Graphite fluoride fiber/polymer composite materials consist of graphite fluoride fibers in epoxy, polytetrafluoroethylene, or polyimide resin. Combines high electrical resistivity with high thermal conductivity and solves heat-transfer problems of many electrical systems. Commercially available in powder form, for use as dry lubricant or cathode material in lithium batteries. Produced by direct fluorination of graphite powder at temperature of 400 to 650 degree C. Applications include printed-circuit boards for high-density power electronics, insulators for magnetic-field cores like those found in alternators and transformers, substrates for thin-film resistors, and electrical-protection layers in aircraft de-icers.

  15. Fluoride absorption: independence from plasma fluoride levels

    SciTech Connect

    Whitford, G.M.; Williams, J.L.

    1986-04-01

    The concept that there are physiologic mechanisms to homeostatically regulate plasma fluoride concentrations has been supported by results in the literature suggesting an inverse relationship between plasma fluoride levels and the absorption of the ion from the gastrointestinal tract of the rat. The validity of the relationship was questioned because of possible problems in the experimental design. The present work used four different methods to evaluate the effect of plasma fluoride levels on the absorption of the ion in rats: (i) the percentage of the daily fluoride intake that was excreted in the urine; (ii) the concentration of fluoride in femur epiphyses; (iii) the net areas under the time-plasma fluoride concentration curves after intragastric fluoride doses; and (iv) the residual amounts or fluoride in the gastrointestinal tracts after the intragastric fluoride doses. None of these methods indicated that plasma fluoride levels influence the rate or the degree or fluoride absorption. It was concluded that, unless extremely high plasma fluoride levels are involved (pharmacologic or toxic doses), the absorption of the ion is independent of plasma levels. The results provide further evidence that plasma fluoride concentrations are not homeostatically regulated.

  16. Substitution mechanisms and location of Co2+ ions in congruent and stoichiometric lithium niobate crystals derived from electron paramagnetic resonance data

    NASA Astrophysics Data System (ADS)

    Grachev, V. G.; Hansen, K.; Meyer, M.; Kokanyan, E. P.; Malovichko, G. I.

    2017-03-01

    Electron paramagnetic resonance (EPR) spectra and their angular dependencies were measured for Co2+ trace impurities in stoichiometric samples of lithium niobate doped with rhodium. It was found that Co2+ substitutes for Li+ in the dominant axial center (CoLi) and that the principal substitution mechanism in stoichiometric lithium niobate is 4Co2+ ↔ 3Li+  +  Nb5+. The four Co2+ ions can occupy the nearest possible cation sites by occupying a Nb site and its three nearest-neighbor Li sites, creating a trigonal pyramid with C3 symmetry, as well as non-neighboring sites (e.g. a CoNb–CoLi pair at the nearest sites on the C3 axis with two nearby isolated single Co2+ ions substituted for Li+). In congruent crystals and samples with Li content enriched by vapor transport equilibrium treatment the excess charge of the Co2+ centers is compensated by lithium vacancies located rather far from the Co2+ ions for the dominant axial center or in the nearest neighborhood for low-symmetry satellite centers (the Co2+ ↔ 2Li+ substitution mechanism). The use of exact numerical diagonalization of the spin-Hamiltonian matrices explains all the details of the EPR spectra and gives a value for hyperfine interaction A || that is several times smaller than that obtained using perturbation formulae. The refined values of A and g-tensor components can be used as reliable cornerstones for ab initio and cluster calculations.

  17. Desired crystal oriented LiFePO4 nanoplatelets in situ anchored on a graphene cross-linked conductive network for fast lithium storage.

    PubMed

    Wang, Bo; Liu, Anmin; Abdulla, Wael Al; Wang, Dianlong; Zhao, X S

    2015-05-21

    Electron transfer and lithium ion diffusion rates are the key factors limiting the lithium ion storage in anisotropic LiFePO4 electrodes. In this work, we employed a facile solvothermal method to synthesize a "platelet-on-sheet" LiFePO4/graphene composite (LFP@GNs), which is LiFePO4 nanoplatelets in situ grown on graphene sheets with highly oriented (010) facets of LiFePO4 crystals. Such a two-phase contact mode with graphene sheets cross-linked to form a three-dimensional porous network is favourable for both fast lithium ion and electron transports. As a result, the designed LFP@GNs displayed a high rate capability (∼56 mA h g(-1) at 60 C) and long life cycling stability (∼87% capacity retention over 1000 cycles at 10 C). For comparison purposes, samples ex situ modified with graphene (LFP/GNs) as well as pure LiFePO4 platelets (LFP) were also prepared and investigated. More importantly, the obtained LFP@GNs can be used as a basic unit for constructing more complex structures to further improve electrochemical performance, such as coating the exposed LFP surface with a thin layer of carbon to build a C@LFP@GN composite to further enhance its cycling stability (∼98% capacity retention over 1000 cycles at 10 C).

  18. Three-Dimensional (3D) Bicontinuous Hierarchically Porous Mn2O3 Single Crystals for High Performance Lithium-Ion Batteries.

    PubMed

    Huang, Shao-Zhuan; Jin, Jun; Cai, Yi; Li, Yu; Deng, Zhao; Zeng, Jun-Yang; Liu, Jing; Wang, Chao; Hasan, Tawfique; Su, Bao-Lian

    2015-10-06

    Bicontinuous hierarchically porous Mn2O3 single crystals (BHP-Mn2O3-SCs) with uniform parallelepiped geometry and tunable sizes have been synthesized and used as anode materials for lithium-ion batteries (LIBs). The monodispersed BHP-Mn2O3-SCs exhibit high specific surface area and three dimensional interconnected bimodal mesoporosity throughout the entire crystal. Such hierarchical interpenetrating porous framework can not only provide a large number of active sites for Li ion insertion, but also good conductivity and short diffusion length for Li ions, leading to a high lithium storage capacity and enhanced rate capability. Furthermore, owing to their specific porosity, these BHP-Mn2O3-SCs as anode materials can accommodate the volume expansion/contraction that occurs with lithium insertion/extraction during discharge/charge processes, resulting in their good cycling performance. Our synthesized BHP-Mn2O3-SCs with a size of ~700 nm display the best electrochemical performance, with a large reversible capacity (845 mA h g(-1) at 100 mA g(-1) after 50 cycles), high coulombic efficiency (>95%), excellent cycling stability and superior rate capability (410 mA h g(-1) at 1 Ag(-1)). These values are among the highest reported for Mn2O3-based bulk solids and nanostructures. Also, electrochemical impedance spectroscopy study demonstrates that the BHP-Mn2O3-SCs are suitable for charge transfer at the electrode/electrolyte interface.

  19. Three-Dimensional (3D) Bicontinuous Hierarchically Porous Mn2O3 Single Crystals for High Performance Lithium-Ion Batteries

    NASA Astrophysics Data System (ADS)

    Huang, Shao-Zhuan; Jin, Jun; Cai, Yi; Li, Yu; Deng, Zhao; Zeng, Jun-Yang; Liu, Jing; Wang, Chao; Hasan, Tawfique; Su, Bao-Lian

    2015-10-01

    Bicontinuous hierarchically porous Mn2O3 single crystals (BHP-Mn2O3-SCs) with uniform parallelepiped geometry and tunable sizes have been synthesized and used as anode materials for lithium-ion batteries (LIBs). The monodispersed BHP-Mn2O3-SCs exhibit high specific surface area and three dimensional interconnected bimodal mesoporosity throughout the entire crystal. Such hierarchical interpenetrating porous framework can not only provide a large number of active sites for Li ion insertion, but also good conductivity and short diffusion length for Li ions, leading to a high lithium storage capacity and enhanced rate capability. Furthermore, owing to their specific porosity, these BHP-Mn2O3-SCs as anode materials can accommodate the volume expansion/contraction that occurs with lithium insertion/extraction during discharge/charge processes, resulting in their good cycling performance. Our synthesized BHP-Mn2O3-SCs with a size of ~700 nm display the best electrochemical performance, with a large reversible capacity (845 mA h g-1 at 100 mA g-1 after 50 cycles), high coulombic efficiency (>95%), excellent cycling stability and superior rate capability (410 mA h g-1 at 1 Ag-1). These values are among the highest reported for Mn2O3-based bulk solids and nanostructures. Also, electrochemical impedance spectroscopy study demonstrates that the BHP-Mn2O3-SCs are suitable for charge transfer at the electrode/electrolyte interface.

  20. [Fluoride emission from different soil minerals at high temperatures].

    PubMed

    Wu, W; Xie, Z; Xu, J; Liu, C

    2001-03-01

    The emission characteristics of fluoride pollutants from montmorillonite, kaolinite, vermiculite, geothite and allophane were studied to elucidate the mechanism of fluoride-releasing from soils during brick and tile making at high temperatures from 300 degrees C to 1000 degrees C. The rate of fluoride emission varied with temperature, mineral type, heating time, specific surface area and cations added to minerals. The escape of crystalline water resulting from crystal lattice collapse at a certain high temperature was found to affect the rate of fluoride emission. Calcium compounds could decrease fluoride emission rate from montmorillonite. At 800 degrees C, the rate of fluoride emission from Ca-treated montmorillonite decreased by 59.6% compared to untreated montmorillonite. The order for fluoride-fixing capacity of the 5 calcium compounds at 800 degrees C was as follows: CaCO3 > CaO > Ca3(PO4)2 > Ca(OH)2 > CaSO4.

  1. Thermal conductivity of γ-irradiated LiF single crystals

    NASA Astrophysics Data System (ADS)

    Basiev, T. T.; Konyushkin, V. A.; Kuznetsov, S. V.; Osiko, V. V.; Popov, P. A.; Fedorov, P. P.

    2008-08-01

    The thermal conductivity of γ-irradiated lithium fluoride (LiF) single crystals has been studied using the method of stationary longitudinal heat flux in a temperature range of 50 300 K. An increase in the irradiation dose to 2 × 109 rad is accompanied by a monotonic decrease in the thermal conductivity by 10% at 300 K and by a factor of 10 at 50 K. This increase in the irradiation dose also leads to an increase in the microhardness of LiF crystals from 140 to 222.5 kgf/mm2.

  2. Spectroscopic properties of long-lifetime Tm3+ optical centers in Ca-Sr-Ba fluorides in the form of single crystals and ceramics at the 1G4-3H5 magnetic dipole allowed transition

    NASA Astrophysics Data System (ADS)

    Doroshenko, M. E.; Papashvili, A. G.; Martynova, K. A.; Konyushkin, V. A.; Nakladov, A. N.; Osiko, V. V.

    2017-02-01

    The spectroscopic properties of new long-lifetime Tm3+ tetragonal optical centers at low (77 K) temperature were investigated using a site-selective time-resolved technique. The absorption and excitation spectra at the 3H6-1G4 transition and the fluorescence spectra at the 1G4-3H5 transition were measured in CaF2, SrF2, and BaF2 single crystals. The appearance of additional weak lines in the excitation and fluorescence spectra in hot-formed ceramics produced from the same crystals was observed. These lines were attributed to the recently observed long-lifetime tetragonal optical centers with a modified local environment formed in fluoride ceramics.

  3. A5RE4X[TO4]4 crystal growth: Fluoride flux synthesis of Na5Ln4F[GeO4]4 (Ln=Pr, Nd), the first quaternary germanate oxyfluorides

    NASA Astrophysics Data System (ADS)

    Latshaw, Allison M.; Wilkins, Branford O.; Morrison, Gregory; Smith, Mark D.; zur Loye, Hans-Conrad

    2016-07-01

    Crystals of Na5Pr4F[GeO4]4 and Na5Nd4F[GeO4]4 were synthesized using a eutectic sodium fluoride, sodium chloride flux. Both compounds crystallize in the tetragonal space group I-4 with lattice parameters of a=12.1173(4) Å and c=5.6795(2) Å (Pr) and of a=12.0642(17) Å and c=5.6674(11) Å (Nd). The structure of the reported compounds is three-dimensional with face and corner sharing lanthanide polyhedra which edge and corner share with isolated germanium tetrahedra. These novel compositions represent the first example of quaternary germanium containing oxyfluorides.

  4. Fracture behavior of lithium single crystal in the framework of (semi-)empirical force field derived from first-principles

    NASA Astrophysics Data System (ADS)

    Groh, Sébastien; Alam, Masud

    2015-06-01

    An approach to derive, from first-principles data, accurate and reliable potentials in the modified embedded-atom method in view of modeling the mechanical behavior of metals is presented in this work and applied to the optimization of a potential representative of lithium (Li). Although the theoretical background of the modified embedded-atom method was considered in this work, the proposed method is general and it can be applied to any other functional form. The main feature of the method is to introduce several path transformations in the material database that are critical for plastic and failure behavior. As part of the potential validation, path transformations different from the ones used for the parameterization procedure are considered. Applied in the case of Li, the material database was enriched with the generalized stacking fault energy curve along the  <1 1 1>  -direction on the {1 1 0}-plane, and with the traction-separation behavior of a {1 0 0}-surface. The path transformations used to enrich the material database were initially derived from first-principles calculations. For validation, the generalized stacking fault energy curves along the  <1 1 1>  -direction on the {1 1 2}- and {1 2 3}-planes were considered for plasticity, while traction-separation behavior of {1 1 0} and {1 1 1}-planes were considered for failure behavior. As part of the validation procedure, the predictions made in the MEAM framework were validated by first-principles data. The final potential accurately reproduced basic equilibrium properties, elastic constants, surface energies in agreement with first-principles predictions, and transition energy between different crystal structures. Furthermore, generalized stacking fault energy curves along the  <1 1 1>  -direction on the {1 1 0}, {1 1 2}, and {1 2 3}-planes, and tensile cohesive stress, characteristic length of fracture, and work of separation of a

  5. Inheritance of Crystallographic Orientation during Lithiation/Delithiation Processes of Single-Crystal α-Fe2O3 Nanocubes in Lithium-Ion Batteries.

    PubMed

    Ma, Xiaowei; Zhang, Manyu; Liang, Chongyun; Li, Yuesheng; Wu, Jingjing; Che, Renchao

    2015-11-04

    Iron oxides are very promising anode materials based on conversion reactions for lithium-ion batteries (LIBs). During conversion processes, the crystal structure and composition of the electrode material are drastically changed. Surprisingly, in our study, inheritance of a crystallographic orientation was found during lithiation/delithiation processes of single-crystal α-Fe2O3 nanocubes by ex situ transmission electron microscopy. Single-crystal α-Fe2O3 was first transformed into numerous Fe nanograins embedded in a Li2O matrix, and then the conversion between Fe and FeO nanograins became the main reversible electrochemical reaction for energy storage. Interestingly, these Fe/FeO nanograins had almost the same crystallographic orientation, indicating that the lithiated/delithiated products can inherit the crystallographic orientation of single-crystal α-Fe2O3. This finding is important for understanding the detailed electrochemical conversion processes of iron oxides, and this feature may also exist during lithiation/delithiation processes of other transition-metal oxides.

  6. Fluoride and Water (For Parents)

    MedlinePlus

    ... Your 1- to 2-Year-Old Fluoride and Water KidsHealth > For Parents > Fluoride and Water A A ... to 19-year-olds continue Fluoride and the Water Supply For more than 60 years, water fluoridation ...

  7. Fluoride and Water (For Parents)

    MedlinePlus

    ... Your 1- to 2-Year-Old Fluoride and Water KidsHealth > For Parents > Fluoride and Water Print A ... to 19-year-olds continue Fluoride and the Water Supply For more than 60 years, water fluoridation ...

  8. Lithium niobate explosion monitor

    DOEpatents

    Bundy, C.H.; Graham, R.A.; Kuehn, S.F.; Precit, R.R.; Rogers, M.S.

    1990-01-09

    Monitoring explosive devices is accomplished with a substantially z-cut lithium niobate crystal in abutment with the explosive device. Upon impact by a shock wave from detonation of the explosive device, the crystal emits a current pulse prior to destruction of the crystal. The current pulse is detected by a current viewing transformer and recorded as a function of time in nanoseconds. In order to self-check the crystal, the crystal has a chromium film resistor deposited thereon which may be heated by a current pulse prior to detonation. This generates a charge which is detected by a charge amplifier. 8 figs.

  9. Lithium niobate explosion monitor

    DOEpatents

    Bundy, Charles H.; Graham, Robert A.; Kuehn, Stephen F.; Precit, Richard R.; Rogers, Michael S.

    1990-01-01

    Monitoring explosive devices is accomplished with a substantially z-cut lithium niobate crystal in abutment with the explosive device. Upon impact by a shock wave from detonation of the explosive device, the crystal emits a current pulse prior to destruction of the crystal. The current pulse is detected by a current viewing transformer and recorded as a function of time in nanoseconds. In order to self-check the crystal, the crystal has a chromium film resistor deposited thereon which may be heated by a current pulse prior to detonation. This generates a charge which is detected by a charge amplifier.

  10. How Does Fluoride Work?

    MedlinePlus

    ... Work? A A A There's fluoride in your toothpaste and even in your water. But how does ... enamel from plaque and sugars. By using fluoride toothpaste, for instance, everyone can enjoy some cavity protection. ...

  11. Unique 1D Co3O4 crystallized nanofibers with (220) oriented facets as high-performance lithium ion battery anode material

    PubMed Central

    Tan, Yanli; Gao, Qiuming; Li, Zeyu; Tian, Weiqian; Qian, Weiwei; Yang, Chunxiao; Zhang, Hang

    2016-01-01

    A novel one-step hydrothermal and calcination strategy was developed to synthesize the unique 1D oriented Co3O4 crystal nanofibers with (220) facets on the carbon matrix derived from the natural, abundant and low cost wool fibers acting as both carbon precursor and template reagent. The resultant W2@Co3O4 nanocomposite exhibited very high specific capacity and favorable high-rate capability when used as anode material of lithium ion battery. The high reversible Li+ ion storage capacity of 986 mAh g−1 was obtained at 100 mA g−1 after 150 cycles, higher than the theoretical capacity of Co3O4 (890 mAh g−1). Even at the higher current density of 1 A g−1, the electrode could still deliver a remarkable discharge capacity of 720 mAh g−1 over 150 cycles. PMID:27217201

  12. Complex investigations of structural and optical homogeneities of low-photorefractivity lithium niobate crystals by the conoscopy and photoinduced and Raman light scattering methods

    NASA Astrophysics Data System (ADS)

    Sidorov, N. V.; Pikoul, O. Yu.; Kruk, A. A.; Teplyakova, N. A.; Yanichev, A. A.; Palatnikov, M. N.

    2015-02-01

    Using photoinduced light scattering, conoscopy, and Raman spectroscopy methods, we have studied stoichiometric lithium niobate crystals and congruent crystals that were doped with Mg(0.078, 0.89 mas %), Zn(0.03, 0.52, 0.62), Cu(0.015), B(0.12), Gd(0.51), Y(0.46), Gd(0.23):Mg(0.75), Mg(0.86):Fe(0.0036), Ta(1.13):Mg(0.011), and Y(0.24):Mg(0.63) cations. It has been found that, depending on the kind of the pattern of photoinduced light scattering, investigated specimens can be divided into three groups. We have shown that the asymmetry of the indicatrix of photoinduced light scattering of LiNbO3 crystals is caused by birefringence of exciting laser radiation as it propagates perpendicularly to the polar axis of the crystal, whereas the asymmetry of the Raman spectrum arises due to the occurrence of spontaneous polarization, the vector of which is directed along the polar axis, and by birefringence. The pattern of the photoinduced light scattering depends on the difference of the refractive indices Δ n = n o - n e of the ordinary ( n o ) and extraordinary ( n e ) rays and their energies E. If En o {ie259-1} En e , the proportion of the photoinduced light scattering has the shape of a three-layer round spot. For equal energies, the pattern has the shape of a symmetric figure-eight. At En o < En e , the figure-eight is asymmetric. In this case, its large "lobe" is directed in the positive direction of the polar axis of the crystal.

  13. Gd(3+)-Yb(3+) Exchange Interactions in LiYb(x)Y(1-x)F4 Single Crystals

    DTIC Science & Technology

    2001-01-01

    fluorolanthanate phases," Inorg. Chem. 9, pp. 1096-1101, 1970. 6. L. E. Misiak, P. Mikolajczak and M. Subotowicz, "Lithium rare-earth fluoride crystal growth and...of Gd 34 in LiYF 4 determined by EPR," Solid State Commun. 45, pp. 1093-1098, 1983. 8. S. K. Misra, M. Kahrizi, P. Mikolajczak and L. E. Misiak, "EPR...and P. Mikolajczak , "EPR of Gd34 -doped single crystals of LiYbxY_,-F 4," Phys. Rev. B 38, pp. 8673-8682, 1988. 10. M. R. St. John and R. J. Myers

  14. High-pressure synthesis and crystal structure of the lithium borate HP-LiB{sub 3}O{sub 5}

    SciTech Connect

    Neumair, Stephanie C.; Vanicek, Stefan; Kaindl, Reinhard; Toebbens, Daniel M.; Wurst, Klaus; Huppertz, Hubert

    2011-09-15

    The new lithium borate HP-LiB{sub 3}O{sub 5} was synthesized under high-pressure/high-temperature conditions of 6 GPa and 1050 deg. C in a multianvil press with a Walker-type module. The compound crystallizes in the space group Pnma (no. 62) with the lattice parameters a=829.7(2), b=759.6(2), and c=1726.8(4) pm (Z=16). The high-pressure compound HP-LiB{sub 3}O{sub 5} is built up from a three-dimensional network of BO{sub 4} tetrahedra and BO{sub 3} groups, which incorporates Li{sup +} ions in channels along the b-axis. Band assignments of measured IR- and Raman spectra were done via quantum-mechanical calculations. Additionally, the thermal behavior of HP-LiB{sub 3}O{sub 5} was investigated. - Graphical abstract: The new high-pressure compound HP-LiB{sub 3}O{sub 5} is built up from a three-dimensional network of BO4 tetrahedra and BO{sub 3} groups, which incorporates Li{sup +} ions in channels along the b-axis. In this paper, the synthesis, the crystal structure, and the properties of HP-LiB{sub 3}O{sub 5} are described. Highlights: > Synthesis of a new lithium borate with the composition HP-LiB{sub 3}O{sub 5} at high pressure. > In contrast to the non-centrosymmetric phase LiB{sub 3}O{sub 5}, this high-pressure phase is centrosymmetric. > First example of ternary alkali borates exhibiting threefold bridging oxygen atoms.

  15. Low-temperature crystal structure, specific heat, and dielectric properties of lithium tetraborate Li2B4O7

    NASA Astrophysics Data System (ADS)

    Senyshyn, A.; Schwarz, B.; Lorenz, T.; Adamiv, V. T.; Burak, Ya. V.; Banys, J.; Grigalaitis, R.; Vasylechko, L.; Ehrenberg, H.; Fuess, H.

    2010-11-01

    Coherent neutron powder diffraction experiments were carried out together with specific heat, dilatometry, and dielectric spectroscopy studies on Li2B4O7 enriched with B11 isotope to 99.3% at low temperatures. Neither traces of phase transformations nor discontinuous changes in physical properties were observed. Negative thermal expansion, anomalous thermal behavior of selected interatomic distances/angles, isotropic displacement parameters on specific sites as well as dielectric constant were discussed in terms of dynamic lithium disorder.

  16. Synthesis of complex fluorides for optical applications

    NASA Astrophysics Data System (ADS)

    Stepleton, Seth Eugene

    Large single crystals of alkali metal fluorides are desirable for many reasons. Fluoride laser crystals have a wide transmission range and on account of their low phonon energies, many efficient laser emissions have been obtained from 285 nm to 4.34 microm.1,2 Inorganic fluoride single crystals feature large bandgaps, very wide optical transmittance ranges from vacuum-ultraviolet (VUV) to mid-IR wavelength regions, lower refractive indices than those of oxides, and typically lower phonon energies (which drastically reduce multiphonon relaxation rates of rare earth ions).3 The main goal of this work was to investigate the hydrothermal synthesis of alkali metal fluorides. Melt techniques have been used thoroughly to research a variety of fluoride systems and showed many phases that were inaccessible due to incongruent melting or phase stability. The existence of these phases was shown but never characterized or grown as a crystalline material. Solution growth in supercritical water was an ideal way to attempt the synthesis of novel compounds and phases. New synthetic routes to known phases and compounds also arose as a part of this work. Optically clear colorless crystals of K2BeF4 were synthesized up to 2 mm in size, and showed no phase transitions up to 1029 K, which suggests paraelectricitys at room temperature, contradicting previous reports.4 Attempts to incorporate a rare earth ion into the fluoroberyllate lattice proved unsuccessful however reactions between beryllium fluoride and lanthanide fluorides could be exploited as a synthetic route to single crystal rare earth fluorides. Hydrothermal reactions with KF produced crystals of three different phases: hexagonal KY2F7, trigonal KYF4 and orthorhombic K2YF5. All were optically clear, colorless crystals, with the K2YF5 crystals growing the largest. This compound is beneficial due to its application as a radiation dosimeter and laser host. 5,6 Optical quality colorless crystals of RbY2F7 and CsY2F7 up to 4 mm in

  17. STS lithium/CF(x) battery

    NASA Technical Reports Server (NTRS)

    Gnacek, Dee

    1991-01-01

    Lithium carbon fluoride batteries are used on Space Shuttle Rocket Boosters and external tanks. These batteries have been extremely successful in terms of mission reliability with the exception of cell yield variances. The function/system and battery descriptions are given. A description is given of the battery range safety system.

  18. Thermal and structural study of the crystal phases and mesophases in the lithium and thallium(i) propanoates and pentanoates binary systems: formation of mixed salts and stabilization of the ionic liquid crystal phase.

    PubMed

    Martínez Casado, F J; Ramos Riesco, M; da Silva, I; Labrador, A; Redondo, M I; García Pérez, M V; López-Andrés, S; Rodríguez Cheda, J A

    2010-08-12

    The temperature and enthalpy vs composition phase diagrams of the binary systems [xC(2)H(5)CO(2)Li + (1 - x)C(2)H(5)CO(2)Tl], and [x(n-C(4)H(9)CO(2)Li) + (1 - x)n-C(4)H(9)CO(2)Tl], where x is the mole fraction, were determined by DSC. Both binary systems display the formation of one 2:1 mixed salt each (at x = 0.667) that appear as a peritectic (incongruent melting) at T(fus) = 512.0 K, and T(fus) = 461.1 K, with Delta(fus)H(m) = 13.76 and 8.08 kJ.mol(-1) for Li-Tl (I) propanoates, and n-pentanoate mixed salts, respectively. The thermotropic liquid crystal of the thallium(I) n-pentanoate transforms into a more stable liquid-crystal phase, which appears in the phase diagram between 380 and 488 K and for x = 0 up to x = 0.56. The crystal structure of thallium(I) propanoate and of the two mixed salts were obtained via X-ray synchrotron radiation diffraction measurements. These compounds present a bilayered structure similar to the two pure lithium salts previously found by our group.

  19. Crystal structure of [bis-(2,6-diiso-propyl-phen-yl) phosphato-κO]tris-(methanol-κO)lithium methanol monosolvate.

    PubMed

    Minyaev, Mikhail E; Nifant'ev, Ilya E; Tavtorkin, Alexander N; Korchagina, Sof'ya A; Zeynalova, Shadana Sh

    2015-05-01

    Crystals of the title compound, [Li{OOP(O-2,6-(i)Pr2C6H3)2}(CH3OH)3]·CH3OH or [Li(C24H34O4P)(CH3OH)3]·CH3OH, have been formed in the reaction between HOOP(O-2,6-(i)Pr2C6H3)2 and LiOH in methanol. The title compound is of inter-est as it represents the first reported crystal structure of the family of lithium phosphate diesters. The {Li(CH3OH)3[O2P(O-(i)Pr2C6H3)2]} unit displays the Li atom in a slightly distorted tetra-hedral coordination environment and exhibits one intra-molecular O-H⋯O hydrogen bond between a coordinating methanol mol-ecule and the terminal non-coordinating O atom of the phosphate group. The unit is connected with two non-coordinating methanol mol-ecules through two inter-molecular O-H⋯O hydrogen bonds, and with a neighbouring unit through two other O-H⋯O inter-actions. These inter-molecular hydrogen bonds lead to the formation of infinite chains along [100]. There are no significant inter-actions between the chains.

  20. Containerless processing of fluoride glass

    NASA Technical Reports Server (NTRS)

    Doremus, Robert H.

    1990-01-01

    Ground-based experiments on glass formation, crystallization, surface tension, vaporization, and chemical durability of a zirconium-barium-lanthanum (ZBL) fluoride glass are summarized. In a container large, columnar grains grew out from the container-glass interface during cooling. The main crystalline phase was alpha BaZrF6. A ZBL glass sphere was levitated acoustically during Shuttle flight STS-11. The glass was melted and then cooled while being levitated (containerless). Crystallization in the recovered sample was very fine and mainly beta BaZr2F10, showing the influence of the container on the nucleation and microstructure of crystallization in the glass. Glass formation should be easier for a containerless glass than in a container.

  1. Solvothermal indium fluoride chemistry: Syntheses and crystal structures of K{sub 5}In{sub 3}F{sub 14}, beta-(NH{sub 4}){sub 3}InF{sub 6} and [NH{sub 4}]{sub 3}[C{sub 6}H{sub 21}N{sub 4}]{sub 2}[In{sub 4}F{sub 21}

    SciTech Connect

    Jayasundera, Anil C.A.; Goff, Richard J.; Li Yang; Finch, Adrian A.; Lightfoot, Philip

    2010-02-15

    The solvothermal syntheses and crystal structures of three indium fluorides are presented. K{sub 5}In{sub 3}F{sub 14} (1) and beta-(NH{sub 4}){sub 3}InF{sub 6} (2) are variants on known inorganic structure types chiolite and cryolite, respectively, with the latter exhibiting a complex and apparently novel structural distortion. [NH{sub 4}]{sub 3}[C{sub 6}H{sub 21}N{sub 4}]{sub 2}[In{sub 4}F{sub 21}] (3) represents a new hybrid composition displaying a unique trimeric metal fluoride building unit. - Graphical abstract: Solvothermal synthesis has been used to prepare three indium fluorides, including a novel hybrid material containing a unique [In{sub 3}F{sub 15}] trimer templated by tren.

  2. Some electronic and magnetic properties of Fluoride ion in Fluoride structure nanocrystals

    NASA Astrophysics Data System (ADS)

    Imtani, Ali Nasir

    2012-01-01

    We have investigated the effects of the environment potential around Fluoride ion on some important electronic and magnetic properties such as dipole polarisability, moment of oscillator strengths S(k) and magnetic susceptibility. The theoretical procedure is based on the variational-perturbation theory with two parameter trial functions incorporated in an ionic model. We estimate these properties in four cases for Fluoride ion; free ion, ion under different potentials, ion in the crystals and ion in nanocrystal, CdF2, CaF2, PbF2, SrF2 and BaF2. Our results indicate that these properties vary with ion environments and the free state of Fluoride ion has higher values and there is linearity behaviour of these properties with lattice constant. For Fluoride ion in nanocrystal, we have found that there is an extra parameter that can also affect the dipole polarisability, the number of ions in the structure.

  3. Holographic recording in a doubly doped lithium niobate crystal with two wavelengths: a blue laser diode and a green laser

    NASA Astrophysics Data System (ADS)

    Komori, Yuichi; Ishii, Yukihiro

    2010-08-01

    A doubly-doped LiNbO3 (LN) crystal has been well used as a nonvolatile two-wavelength recording material. By using two levels of the crystal, two-kind holograms can be recorded on one crystal; a hologram is recorded with a 405-nm blue laser diode (LD) for a deep Mn level, and another hologram is with a 532-nm green laser for a shallow Fe level. The recording capacity doubles. A 780-nm LD is non-volatile reconstructing source since the LD line is insensitive to both levels. Multiplexed reconstructed images are demonstrated by using a sharp angular selectivity of a volume LN crystal keeping Bragg condition with spherical reconstructions.

  4. Fluoride and Oral Health.

    PubMed

    O'Mullane, D M; Baez, R J; Jones, S; Lennon, M A; Petersen, P E; Rugg-Gunn, A J; Whelton, H; Whitford, G M

    2016-06-01

    The discovery during the first half of the 20th century of the link between natural fluoride, adjusted fluoride levels in drinking water and reduced dental caries prevalence proved to be a stimulus for worldwide on-going research into the role of fluoride in improving oral health. Epidemiological studies of fluoridation programmes have confirmed their safety and their effectiveness in controlling dental caries. Major advances in our knowledge of how fluoride impacts the caries process have led to the development, assessment of effectiveness and promotion of other fluoride vehicles including salt, milk, tablets, toothpaste, gels and varnishes. In 1993, the World Health Organization convened an Expert Committee to provide authoritative information on the role of fluorides in the promotion of oral health throughout the world (WHO TRS 846, 1994). This present publication is a revision of the original 1994 document, again using the expertise of researchers from the extensive fields of knowledge required to successfully implement complex interventions such as the use of fluorides to improve dental and oral health. Financial support for research into the development of these new fluoride strategies has come from many sources including government health departments as well as international and national grant agencies. In addition, the unique role which industry has played in the development, formulation, assessment of effectiveness and promotion of the various fluoride vehicles and strategies is noteworthy. This updated version of 'Fluoride and Oral Health' has adopted an evidence-based approach to its commentary on the different fluoride vehicles and strategies and also to its recommendations. In this regard, full account is taken of the many recent systematic reviews published in peer reviewed literature.

  5. Mild hydrothermal crystal growth of new uranium(IV) fluorides, Na3.13Mg1.43U6F30 and Na2.50Mn1.75U6F30: Structures, optical and magnetic properties

    NASA Astrophysics Data System (ADS)

    Yeon, Jeongho; Smith, Mark D.; Tapp, Joshua; Möller, Angela; zur Loye, Hans-Conrad

    2016-04-01

    Two new uranium(IV) fluorides, Na3.13Mg1.43U6F30 (1) and Na2.50Mn1.75U6F30 (2), were synthesized through an in situ mild hydrothermal route, and were structurally characterized by single crystal X-ray diffraction. The compounds exhibit complex crystal structures composed of corner- or edge-shared UF9 and MF6 (M=Mg, Mn) polyhedra, forming hexagonal channels in the three-dimensional framework, in which ordered or disordered divalent metal and sodium atoms reside. The large hexagonal voids contain the nearly regular M(II)F6 octahedra and sodium ions, whereas the small hexagonal cavities include M(II) and sodium ions on a mixed-occupied site. Magnetic susceptibility measurements yielded effective magnetic moments of 8.36 and 11.6 μB for 1 and 2, respectively, confirming the presence and oxidation states of U(IV) and Mn(II). The large negative Weiss constants indicate the spin gap between a triplet and a singlet state in the U(IV). Magnetization data as a function of applied fields revealed that 2 exhibits paramagnetic behavior due to the nonmagnetic singlet ground state of U(IV) at low temperature. UV-vis diffuse reflectance and X-ray photoelectron spectroscopy data were also analyzed.

  6. Preferential growth orientation of laser-patterned LiNbO{sub 3} crystals in lithium niobium silicate glass

    SciTech Connect

    Komatsu, T.; Koshiba, K.; Honma, T.

    2011-02-15

    Dots and lines consisting of LiNbO{sub 3} crystals are patterned on the surface of 1CuO-40Li{sub 2}O-32Nb{sub 2}O{sub 5}-28SiO{sub 2} (mole ratio) glass by irradiations of continuous-wave Nd:YAG laser (wavelength: {lambda}=1064 nm), diode laser ({lambda}=795 nm), and Yb:YVO{sub 4} fiber laser ({lambda}=1080 nm), and the feature of laser-patterned LiNbO{sub 3} crystal growth is examined from linearly polarized micro-Raman scattering spectrum measurements. LiNbO{sub 3} crystals with the c-axis orientation are formed at the edge parts of the surface and cross-section of dots. The growth direction of an LiNbO{sub 3} along the laser scanning direction is the c-axis. It is proposed that the profile of the temperature distribution in the laser-irradiated region and its change along laser scanning would be one of the most important conditions for the patterning of crystals with a preferential growth orientation. Laser irradiation giving a narrow width is also proposed to be one of the important factors for the patterning of LiNbO{sub 3} crystal lines with homogeneous surface morphologies. -- Graphical abstract: Polarized optical microscope observations for the surface and cross-section of the dot obtained by LD laser ({lambda}=795 nm) irradiations of P=1.4 W and t=20 s in Cu-LNS glass. Schematic model for the orientation of LiNbO{sub 3} crystals at the edge parts of the surface and cross-section of the dot is also shown. Display Omitted Research highlights: > Dots and lines with LiNbO{sub 3} crystals are patterned on the glass surface by laser irradiations. > LiNbO{sub 3} crystals with the c-axis orientation are formed at the edge parts of the surface and cross-section of dots. > The profile of the temperature distribution in the laser-irradiated region is one of the most important conditions for the patterning of highly oriented crystals.

  7. Lithium Ion Mobility in Lithium Phosphidosilicates: Crystal Structure, (7) Li, (29) Si, and (31) P MAS NMR Spectroscopy, and Impedance Spectroscopy of Li8 SiP4 and Li2 SiP2.

    PubMed

    Toffoletti, Lorenzo; Kirchhain, Holger; Landesfeind, Johannes; Klein, Wilhelm; van Wüllen, Leo; Gasteiger, Hubert A; Fässler, Thomas F

    2016-12-05

    The need to improve electrodes and Li-ion conducting materials for rechargeable all-solid-state batteries has drawn enhanced attention to the investigation of lithium-rich compounds. The study of the ternary system Li-Si-P revealed a series of new compounds, two of which, Li8 SiP4 and Li2 SiP2 , are presented. Both phases represent members of a new family of Li ion conductors that display Li ion conductivity in the range from 1.15(7)×10(-6) Scm(-1) at 0 °C to 1.2(2)×10(-4) Scm(-1) at 75 °C (Li8 SiP4 ) and from 6.1(7)×10(-8) Scm(-1) at 0 °C to 6(1)×10(-6) Scm(-1) at 75 °C (Li2 SiP2 ), as determined by impedance measurements. Temperature-dependent solid-state (7) Li NMR spectroscopy revealed low activation energies of about 36 kJ mol(-1) for Li8 SiP4 and about 47 kJ mol(-1) for Li2 SiP2 . Both compounds were structurally characterized by X-ray diffraction analysis (single crystal and powder methods) and by (7) Li, (29) Si, and (31) P MAS NMR spectroscopy. Both phases consist of tetrahedral SiP4 anions and Li counterions. Li8 SiP4 contains isolated SiP4 units surrounded by Li atoms, while Li2 SiP2 comprises a three-dimensional network based on corner-sharing SiP4 tetrahedra, with the Li ions located in cavities and channels.

  8. Fluorides and non-fluoride remineralization systems.

    PubMed

    Amaechi, Bennett T; van Loveren, Cor

    2013-01-01

    Caries develops when the equilibrium between de- and remineralization is unbalanced favoring demineralization. De- and remineralization occur depending on the degree of saturation of the interstitial fluids with respect to the tooth mineral. This equilibrium is positively influenced when fluoride, calcium and phosphate ions are added favoring remineralization. In addition, when fluoride is present, it will be incorporated into the newly formed mineral which is then less soluble. Toothpastes may contain fluoride and calcium ions separately or together in various compounds (remineralization systems) and may therefore reduce demineralization and promote remineralization. Formulating all these compounds in one paste may be challenging due to possible premature calcium-fluoride interactions and the low solubility of CaF2. There is a large amount of clinical evidence supporting the potent caries preventive effect of fluoride toothpastes indisputably. The amount of clinical evidence of the effectiveness of the other remineralization systems is far less convincing. Evidence is lacking for head to head comparisons of the various remineralization systems.

  9. Structural and photoluminescence studies on europium-doped lithium tetraborate (Eu:Li2B4O7) single crystal grown by microtube Czochralski (μT-Cz) technique

    NASA Astrophysics Data System (ADS)

    A, Kumaresh; R, Arun Kumar; N, Ravikumar; U, Madhusoodanan; B, S. Panigrahi; K, Marimuthu; M, Anuradha

    2016-05-01

    Rare earth europium (Eu3+)-doped lithium tetraborate (Eu:Li2B4O7) crystal is grown from its stoichiometric melt by microtube Czochralski pulling technique (μT-Cz) for the first time. The grown crystals are subjected to powder x-ray diffraction (PXRD) analysis which reveals the tetragonal crystal structure of the crystals. UV-vis-NIR spectral analysis is carried out to study the optical characteristics of the grown crystals. The crystal is transparent in the entire visible region, and the lower cutoff is observed to be at 304 nm. The existence of BO3 and BO4 bonding structure and the molecular associations are analyzed by Fourier transform infrared (FTIR) spectroscopy. The results of excitation and emission-photoluminescence spectra of europium ion incorporated in lithium tetraborate (LTB) single crystal reveal that the observations of peaks at 258, 297, and 318 nm in the excitation spectra and peaks at 579, 591, 597, 613, and 651 nm are observed in the emission spectra. The chromaticity coordinates are calculated from the emission spectra, and the emission intensity of the grown crystal is characterized through a CIE 1931 (Commission International d’Eclairage) color chromaticity diagram. Project supported by the Department of Science and Technology-Science and Engineering Research Board (Grant No. SR/S2/LOP-0012/2011), the Government of India for Awarding Major Research Project, the University Grants Commission-Department of Atomic Research-Consortium for Scientific Research (Grant No. CSR-KN/CSR-63/2014-2015/503), and the Kalpakkam and Indore, India.

  10. PRODUCTION OF THORIUM FLUORIDE

    DOEpatents

    Zachariasen, W.H.

    1959-08-11

    A process is presented for producing anhydrous thorium fluoride comprising the step of contacting a saturated aqueous solution of thorium nitrate with an aqueous solution of hydrofluoric acid having a concentration of about 45 to 50% by weight at a temperature above 70 deg C whereby anhydrous thorium fluoride precipitates.

  11. Effects of Gravity on Processing Heavy Metal Fluoride Fibers

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Workman, Gary L.; Smith, Guy A.

    1997-01-01

    The effects of gravity on the crystal nucleation of heavy metal fluoride fibers have been studied in preliminary experiments utilizing NASA's KC-135 reduced gravity aircraft and a microgravity sounding rocket flight. Commercially produced fibers were heated to the crystallization temperature in normal and reduced gravity. The fibers processed in normal gravity showed complete crystallization while the fibers processed in reduced gravity did not show signs of crystallization.

  12. Characterization of pore and crystal structure of synthesized LiBOB with varying quality of raw materials as electrolyte for lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Lestariningsih, Titik; Ratri, Christin Rina; Wigayati, Etty Marty; Sabrina, Qolby

    2016-02-01

    Characterization of pore structure and crystal structure of the LiB(C2O4)2H2O or LIBOB compound has been performed in this study. These recent years, research regarding LiBOB electrolyte salt have been performed using analytical-grade raw materials, therefore this research was aimed to synthesized LiBOB electrolyte salt using the cheaper and abundant technical-grade raw materials. Lithium hydroxide (LiOH), oxalic acid dihydrate (H2C2O4.2H2O), and boric acid (H3BO3) both in technical-grade and analytical-grade quality were used as raw materials for the synthesis of LiBOB. Crystal structure characterization results of synthesized LiBOB from both technical-grade and analytical-grade raw materials have shown the existence of LiBOB and LiBOB hydrate phase with orthorombic structure. These results were also confirmed by FT-IR analysis, which showed the functional groups of LiBOB compounds. SEM analysis results showed that synthesized LiBOB has spherical structure, while commercial LiBOB has cylindrical structure. Synthesized LiBOB has a similar pore size of commercial LiBOB, i.e. 19 nm (mesoporous material). Surface area of synthesized LiBOB from analytical-grade raw materials and technical-grade materials as well as commercial LIBOB were 88.556 m2/g, 41.524 m2/g, and 108.776 m2/g, respectively. EIS analysis results showed that synthesized LiBOB from technical-grade raw materials has lower conductivity than synthesized LiBOB from analytical-grade raw materials.

  13. Refinement of the crystal structure of calcium-lithium-aluminum tourmaline from the pegmatite vein in the Sangilen Upland (Tuva Republic)

    SciTech Connect

    Rozhdestvenskaya, I. V. Bronzova, Yu. M.; Frank-Kamenetskaya, O. V.; Zolotarev, A. A.; Kuznetsova, L. G.; Bannova, I. I.

    2008-03-15

    The crystal structure of a natural calcium-lithium-aluminum tourmaline, which has the unique composition (Ca{sub 0.62}Na{sub 0.32}{open_square}{sub 0.06})(Al{sub 1.08}Li{sub 0.99}Fe{sub 0.66}{sup 2+} Mg{sub 0.24}Ti{sub 0.03})Al{sub 6}[Si{sub 6}O{sub 18}](BO{sub 3}){sub 3}(OH{sub 2.28}O{sub 0.72}) . (F{sub 0.84}O{sub 0.16}), is refined (R = 0.019, R{sub w} = 0.022, S = 1.47). It is found that the O(1)(W) site is split into two sites, O(1) and O(11), which are incompletely occupied by fluorine and oxygen anions, respectively, and that the O(3)(V) site contains bivalent oxygen anions. The solid solution studied is close in composition to the liddicoatite mineral species and differs from the latter one by the Li: Al ratio in the Y octahedra and the presence of bivalent oxygen anions in the O(3) site. The tourmaline studied differs from the hypothetical oxyliddicoatite by the population of the O(1)(W) site by fluorine and accommodation of additional oxygen anions in the O(3)(V) site.

  14. Refinement of the crystal structure of calcium-lithium-aluminum tourmaline from the pegmatite vein in the Sangilen Upland (Tuva Republic)

    SciTech Connect

    Rozhdestvenskaya, I. V. Bronzova, Yu. M.; Frank-Kamenetskaya, O. V.; Zolotarev, A. A.; Kuznetsova, L. G.; Bannova, I. I.

    2008-03-15

    The crystal structure of a natural calcium-lithium-aluminum tourmaline, which has the unique composition (Ca{sub 0.62}Na{sub 0.32}{open_square}{sub 0.06})(Al{sub 1.08}Li{sub 0.99}Fe{sub 0.66}{sup 2+} Mg{sub 0.24}Ti{sub 0.03})Al{sub 6}[Si{sub 6}O{sub 18}](BO{sub 3}){sub 3}(OH{sub 2.28}O{sub 0.72}) {center_dot} (F{sub 0.84}O{sub 0.16}), is refined (R = 0.019, R{sub w} = 0.022, S = 1.47). It is found that the O(1)(W) site is split into two sites, O(1) and O(11), which are incompletely occupied by fluorine and oxygen anions, respectively, and that the O(3)(V) site contains bivalent oxygen anions. The solid solution studied is close in composition to the liddicoatite mineral species and differs from the latter one by the Li: Al ratio in the Y octahedra and the presence of bivalent oxygen anions in the O(3) site. The tourmaline studied differs from the hypothetical oxyliddicoatite by the population of the O(1)(W) site by fluorine and accommodation of additional oxygen anions in the O(3)(V) site.

  15. Indium fluoride glass fibers

    NASA Astrophysics Data System (ADS)

    Saad, Mohammed

    2012-03-01

    Fluoride glasses are the only material that transmit light from ultraviolet to mid-infrared and can be drawn into industrial optical fibers. The mechanical and optical properties of new indium fluoride glass fibers have been investigated. Multimode fiber 190 microns, has very high mechanical strength greater than 100 kpsi and optical loss as low as 45 dB/km between 2 and 4 microns. Unlike chalcogenide glass fibers, indium fluoride fiber has a wide transmission window from 0.3 to 5.5 microns without any absorption peak. Indium fluoride glass fibers are the technology of choice for all application requiring transmission up to 5 micron such as infrared contour measure (IRCM) and chemical sensing. Furthermore, Indium fluoride glasses have low phonon energy and can be heavily doped and co-doped whit rare-earth elements. Therefore they are very promising candidates for infrared fiber lasers.

  16. The Effect of Crystal Face of Fe2O3 on the Electrochemical Performance for Lithium-ion Batteries

    PubMed Central

    Chen, Minmin; Zhao, Enyue; Yan, Qingbo; Hu, Zhongbo; Xiao, Xiaoling; Chen, Dongfeng

    2016-01-01

    Fe2O3 nanorods exposing (001) and (010) plane as well as Fe2O3 nanosheets exposing (001) plane have been successfully synthesized. Fe2O3 nanosheets exhibit better cycle performance and rate capabilities than that of Fe2O3 nanorods. The discharge capacity of Fe2O3 nanosheets can stabilize at 865 mAh/g at the rate of 0.2 C (1C = 1000 mA/g) and 570 mAh/g at the rate of 1.2 C after 80 cycles, which increased by 90% and 79% compared with 456 mAh/g and 318 mAh/g of Fe2O3 nanorods. In comparison with (010) plane, the (001) plane of hematite possesses larger packing density of Fe3+ and O2−, which is responsible for the superior electrochemical performances of Fe2O3 nanosheets than that of Fe2O3 nanorods. In addition, potentiostatic intermittent titration (PITT) results show the diffusion coefficients of Li+ (DLi) of Fe2O3 nanosheets is higher than that of Fe2O3 nanorods. The higher diffusion coefficients of Li+ is favorable for the excellent lithium-storage capabilities and rate capability of Fe2O3 nanosheets. Inspired by our results, we can design and synthesize Fe2O3 or other electrodes with high performances according to their structure features in future. PMID:27380891

  17. The Effect of Crystal Face of Fe2O3 on the Electrochemical Performance for Lithium-ion Batteries

    NASA Astrophysics Data System (ADS)

    Chen, Minmin; Zhao, Enyue; Yan, Qingbo; Hu, Zhongbo; Xiao, Xiaoling; Chen, Dongfeng

    2016-07-01

    Fe2O3 nanorods exposing (001) and (010) plane as well as Fe2O3 nanosheets exposing (001) plane have been successfully synthesized. Fe2O3 nanosheets exhibit better cycle performance and rate capabilities than that of Fe2O3 nanorods. The discharge capacity of Fe2O3 nanosheets can stabilize at 865 mAh/g at the rate of 0.2 C (1C = 1000 mA/g) and 570 mAh/g at the rate of 1.2 C after 80 cycles, which increased by 90% and 79% compared with 456 mAh/g and 318 mAh/g of Fe2O3 nanorods. In comparison with (010) plane, the (001) plane of hematite possesses larger packing density of Fe3+ and O2‑, which is responsible for the superior electrochemical performances of Fe2O3 nanosheets than that of Fe2O3 nanorods. In addition, potentiostatic intermittent titration (PITT) results show the diffusion coefficients of Li+ (DLi) of Fe2O3 nanosheets is higher than that of Fe2O3 nanorods. The higher diffusion coefficients of Li+ is favorable for the excellent lithium-storage capabilities and rate capability of Fe2O3 nanosheets. Inspired by our results, we can design and synthesize Fe2O3 or other electrodes with high performances according to their structure features in future.

  18. Crystal Structures of Beryllium Fluoride-Free and Beryllium Fluoride-Bound CheY in Complex with the Conserved C-Terminal Peptide of CheZ Reveal Dual Binding Modes Specific to CheY Conformation

    SciTech Connect

    Guhaniyogi,J.; Robinson, V.; Stock, A.

    2006-01-01

    Chemotaxis, the environment-specific swimming behavior of a bacterial cell is controlled by flagellar rotation. The steady-state level of the phosphorylated or activated form of the response regulator CheY dictates the direction of flagellar rotation. CheY phosphorylation is regulated by a fine equilibrium of three phosphotransfer activities: phosphorylation by the kinase CheA, its auto-dephosphorylation and dephosphorylation by its phosphatase CheZ. Efficient dephosphorylation of CheY by CheZ requires two spatially distinct protein-protein contacts: tethering of the two proteins to each other and formation of an active site for dephosphorylation. The former involves interaction of phosphorylated CheY with the small highly conserved C-terminal helix of CheZ (CheZ{sub C}), an indispensable structural component of the functional CheZ protein. To understand how the CheZ{sub C} helix, representing less than 10% of the full-length protein, ascertains molecular specificity of binding to CheY, we have determined crystal structures of CheY in complex with a synthetic peptide corresponding to 15 C-terminal residues of CheZ (CheZ{sub 200-214}) at resolutions ranging from 2.0 Angstroms to 2.3 Angstroms. These structures provide a detailed view of the CheZC peptide interaction both in the presence and absence of the phosphoryl analog, BeF{sub 3}{sup -}. Our studies reveal that two different modes of binding the CheZ{sub 200-214} peptide are dictated by the conformational state of CheY in the complex. Our structures suggest that the CheZ{sub C} helix binds to a 'meta-active' conformation of inactive CheY and it does so in an orientation that is distinct from the one in which it binds activated CheY. Our dual binding mode hypothesis provides implications for reverse information flow in CheY and extends previous observations on inherent resilience in CheY-like signaling domains.

  19. A Study of Mechanochemical Doping of Fluoride Crystals with a Fluorite Structure by Er3+ Ions via Electron Paramagnetic Resonance Spectra

    NASA Astrophysics Data System (ADS)

    Irisova, I. A.; Rodionov, A. A.; Tayurskii, D. A.; Yusupov, R. V.

    2014-05-01

    Using electron paramagnetic resonance (EPR) spectroscopy, we have shown that, upon mecha- noactivated doping of powders of compounds CaF2, SrF2, and BaF2 with Er3+ ions, impurity centers of single erbium ions with cubic symmetry are formed. Investigations of dependences of EPR spectra intensities on the particle size show that the process of mechanochemical doping with Er3+ ions proceeds differently for CaF2, SrF2, and BaF2 host matrices. In the case of CaF2, impurity centers are localized in a very thin near-surface layer of CaF2 particles, in SrF2, the impurity is distributed over the volume of particles, while, in BaF2, there is a layer of a finite thickness for which the probability of doping in the course of mechanosynthesis is very small and the impurity of the rare-earth element is localized in the core of large particles. These data can be explained assuming that the result of mechanosynthesis of particles of fluorides with a fluorite structure doped with Er3+ ions at room temperature is governed by two processes—mechanoactivated diffusion of rare-earth ions into particles and segregation of impurity ions at grain boundaries. In this case, the typical scales for compounds CaF2, SrF2, and BaF2 considerably differ from each other.

  20. Continuous tuning of a microlaser-pumped optical parametric generator by use of a cylindrical periodically poled lithium niobate crystal.

    PubMed

    Fève, Jean-Philippe; Boulanger, Benoît; Ménaert, Bertrand; Pacaud, Olivier

    2003-06-15

    An optical parametric generator with a cylindrical periodically poled LiNbO3 crystal and a Nd:YAG commercial microchip pump laser yields continuous tuning of the emitted wavelengths over a broad spectral range (1.42-1.7 microm and 2.8-4.2 microm), with large efficiency, a high repetition rate, and low divergence, in a compact and stable device.

  1. Controlled synthesis of series NixCo3-xO4 products: Morphological evolution towards quasi-single-crystal structure for high-performance and stable lithium-ion batteries.

    PubMed

    Zhou, Yu; Liu, Yong; Zhao, Wenxia; Wang, Hai; Li, Baojun; Zhou, Xiang; Shen, Hui

    2015-06-24

    Transition metal oxides are very promising alternative anode materials for high-performance lithium-ion batteries (LIBs). However, their conversion reactions and concomitant volume expansion cause the pulverization, leading to poor cycling stability, which limit their applications. Here, we present the quasi-single-crystal Ni(x)Co(3-x)O4 hexagonal microtube (QNHM) composed of continuously twinned single crystal submicron-cubes as anode materials for LIBs with high energy density and long cycle life. At the current density of 0.8 A g(-1), it can deliver a high discharge capacities of 1470 mAh g(-1) over 100 cycles (105% of the 2nd cycle) and 590 mAh g(-1) even after 1000 cycles. To better understand what underlying factors lead our QNHMs to achieve excellent electrochemical performance, a series of Ni(x)Co(3-x)O4 products with systematic shape evolution from spherical to polyhedral, and cubic particles as well as circular microtubes consisted of spheres and square microtubes composed of polyhedra have been synthesized. The excellent electrochemical performance of QNHMs is attributed to the unique stable quasi-single-crystal structure, which can both provide efficient electrical transport pathway and suppress the electrode pulverization. It is important to note that such quasi-single-crystal structure would be helpful to explore other high-energy lithium storage materials based on alloying or conversion reactions.

  2. Controlled synthesis of series NixCo3-xO4 products: Morphological evolution towards quasi-single-crystal structure for high-performance and stable lithium-ion batteries

    PubMed Central

    Zhou, Yu; Liu, Yong; Zhao, Wenxia; Wang, Hai; Li, Baojun; Zhou, Xiang; Shen, Hui

    2015-01-01

    Transition metal oxides are very promising alternative anode materials for high-performance lithium-ion batteries (LIBs). However, their conversion reactions and concomitant volume expansion cause the pulverization, leading to poor cycling stability, which limit their applications. Here, we present the quasi-single-crystal NixCo3-xO4 hexagonal microtube (QNHM) composed of continuously twinned single crystal submicron-cubes as anode materials for LIBs with high energy density and long cycle life. At the current density of 0.8 A g−1, it can deliver a high discharge capacities of 1470 mAh g−1 over 100 cycles (105% of the 2nd cycle) and 590 mAh g−1 even after 1000 cycles. To better understand what underlying factors lead our QNHMs to achieve excellent electrochemical performance, a series of NixCo3-xO4 products with systematic shape evolution from spherical to polyhedral, and cubic particles as well as circular microtubes consisted of spheres and square microtubes composed of polyhedra have been synthesized. The excellent electrochemical performance of QNHMs is attributed to the unique stable quasi-single-crystal structure, which can both provide efficient electrical transport pathway and suppress the electrode pulverization. It is important to note that such quasi-single-crystal structure would be helpful to explore other high-energy lithium storage materials based on alloying or conversion reactions. PMID:26103885

  3. Hydrogen, lithium, and lithium hydride production

    DOEpatents

    Brown, Sam W; Spencer, Larry S; Phillips, Michael R; Powell, G. Louis; Campbell, Peggy J

    2014-03-25

    A method of producing high purity lithium metal is provided, where gaseous-phase lithium metal is extracted from lithium hydride and condensed to form solid high purity lithium metal. The high purity lithium metal may be hydrided to provide high purity lithium hydride.

  4. Quantitative determination of lattice fluoride effects on the solubility and crystallinity of carbonated apatites with incorporated fluoride.

    PubMed

    Yan, G; Moribe, K; Otsuka, M; Papangkorn, K; Higuchi, W I

    2013-01-01

    The purpose of this study was to evaluate quantitatively the effects of fluoride on the solubility and crystallinity of carbonated apatites (CAPs) after its incorporation into the crystal lattice using the metastable equilibrium solubility (MES) distribution method. Fluoride-incorporated CAPs (F-CAPs) of two different carbonate levels (3 and 5%) and fluoride contents from 0 to 20,000 µg/g were synthesized. X-ray diffraction experiments and Rietveld analysis were conducted to obtain crystallite microstrain and unit cell parameters. Acetate buffer MES solution media were prepared at two solution fluoride concentrations (0.2 and 2.0 mg/l) and at two pHs (5.0 and 5.7). The unit cell a-axis values of the F-CAPs were found to decrease as the fluoride content increased, consistent with the fluoride being incorporated into the crystal lattice. The fluoride concentrations in the MES solution media were high enough to provide a 'swamping' effect such that the fluoride released from the F-CAPs during dissolution was minimal in changing the solution fluoride concentration. Employing the MES distribution superposition method, it was shown that the surface complex possessing the fluorapatite (FAP) stoichiometry [Ca10(PO4)6F2] accounted for the MES distribution behavior of all experiments. In addition, the mean pIFAP [the value of -log(aCa(10)aPO4(6)aF(2)) calculated from the ionic activity product based on FAP stoichiometry of the MES dissolution media in which 50% of the F-CAPs had dissolved] correlated well with the crystallite microstrain parameters of the F-CAPs. The incorporated fluoride in the F-CAPs showed only modest effects on F-CAP crystallinity and solubility.

  5. Electrical Relaxation in Calcium Fluoride Doped with Thorium and Zirconium.

    DTIC Science & Technology

    1986-09-01

    9, 1055 (1976). 4. M. Ouwerkerk , F. F. Veldkamp, N. H. Andersen, and J . Schoonman, Solid State Ionics, 16, 125 (1985). 5. S. F. Matar, J . M. Reau, P...AD-Al?2 366 ELECTRICAL RELAXATION IN CALCIUM FLUORIDE DOPED WITH L1/ THORIUM AND ZIRCONIUM(U) NAYRL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS J J ...Fluoride Doped with Thorium and Zirconium by John J . Fontanella & Mary C. Wintersgill Prepared for Publication in Crystal Lattice Defects and Amorphous

  6. The structure and properties of quartz crystals grown from fluoride solutions: Part II. The burgers vector of the growth screw superdislocations

    SciTech Connect

    Chuvyrov, A. N.; Mazitov, R. M.; Kalimgulov, A. R.; Lebedev, Yu. A.

    2009-07-15

    The birefringence method is used to investigate the distribution of microstresses around screw superdislocations with a hollow core in quartz crystals and to determine the Burgers vector and core size. The core size was found to be 5 x 10{sup -7} m; this value was confirmed independently by studying the light diffraction on hollow cores in different quartz cuts.

  7. Formation of color centers in a thin layer of LiF crystals under VUV radiation from a barrier discharge

    NASA Astrophysics Data System (ADS)

    Milyutina, E. V.; Petrovskii, A. F.; Rakevich, A. L.; Martynovich, E. F.

    2014-05-01

    Under radiation from a barrier discharge, luminescent color centers are formed in a surface layer of lithium fluoride crystal served as a dielectric barrier. Analysis of the damping kinetics and luminescence spectra has revealed these centers to be F {3/+} and F 2 centers. Structural defects are mainly formed via the photon-induced mechanism (i.e., defects are formed due to the generation of electron-hole pairs as a result of absorption of photons of barrier-discharge radiation). Barrier discharge in different gases can be successfully used to form thin layers containing luminescence centers on the surface of transparent insulators for various scientific and practical applications.

  8. Phase transformation mechanism in lithium manganese nickel oxide revealed by single-crystal hard X-ray microscopy

    NASA Astrophysics Data System (ADS)

    Kuppan, Saravanan; Xu, Yahong; Liu, Yijin; Chen, Guoying

    2017-02-01

    Understanding the reaction pathway and kinetics of solid-state phase transformation is critical in designing advanced electrode materials with better performance and stability. Despite the first-order phase transition with a large lattice mismatch between the involved phases, spinel LiMn1.5Ni0.5O4 is capable of fast rate even at large particle size, presenting an enigma yet to be understood. The present study uses advanced two-dimensional and three-dimensional nano-tomography on a series of well-formed LixMn1.5Ni0.5O4 (0<=x<=1) crystals to visualize the mesoscale phase distribution, as a function of Li content at the sub-particle level. Inhomogeneity along with the coexistence of Li-rich and Li-poor phases are broadly observed on partially delithiated crystals, providing direct evidence for a concurrent nucleation and growth process instead of a shrinking-core or a particle-by-particle process. Superior kinetics of (100) facets at the vertices of truncated octahedral particles promote preferential delithiation, whereas the observation of strain-induced cracking suggests mechanical degradation in the material.

  9. Phase transformation mechanism in lithium manganese nickel oxide revealed by single-crystal hard X-ray microscopy

    DOE PAGES

    Kuppan, Saravanan; Xu, Yahong; Liu, Yijin; ...

    2017-02-01

    Understanding the reaction pathway and kinetics of solid-state phase transformation is critical in designing advanced electrode materials with better performance and stability. Despite the first-order phase transition with a large lattice mismatch between the involved phases, spinel LiMn1.5Ni0.5O4 is capable of fast rate even at large particle size, presenting an enigma yet to be understood. The present study uses advanced two-dimensional and three-dimensional nano-tomography on a series of well-formed LixMn1.5Ni0.5O4 (0 ≤ x ≤ 1) crystals to visualize the mesoscale phase distribution, as a function of Li content at the sub-particle level. Inhomogeneity along with the coexistence of Li-rich andmore » Li-poor phases are broadly observed on partially delithiated crystals, providing direct evidence for a concurrent nucleation and growth process instead of a shrinking-core or a particle-by-particle process. As a result, superior kinetics of (100) facets at the vertices of truncated octahedral particles promote preferential delithiation, whereas the observation of strain-induced cracking suggests mechanical degradation in the material.« less

  10. Phase transformation mechanism in lithium manganese nickel oxide revealed by single-crystal hard X-ray microscopy

    PubMed Central

    Kuppan, Saravanan; Xu, Yahong; Liu, Yijin; Chen, Guoying

    2017-01-01

    Understanding the reaction pathway and kinetics of solid-state phase transformation is critical in designing advanced electrode materials with better performance and stability. Despite the first-order phase transition with a large lattice mismatch between the involved phases, spinel LiMn1.5Ni0.5O4 is capable of fast rate even at large particle size, presenting an enigma yet to be understood. The present study uses advanced two-dimensional and three-dimensional nano-tomography on a series of well-formed LixMn1.5Ni0.5O4 (0≤x≤1) crystals to visualize the mesoscale phase distribution, as a function of Li content at the sub-particle level. Inhomogeneity along with the coexistence of Li-rich and Li-poor phases are broadly observed on partially delithiated crystals, providing direct evidence for a concurrent nucleation and growth process instead of a shrinking-core or a particle-by-particle process. Superior kinetics of (100) facets at the vertices of truncated octahedral particles promote preferential delithiation, whereas the observation of strain-induced cracking suggests mechanical degradation in the material. PMID:28145406

  11. Preparation and physical characteristics of a lithium-beryllium-substituted fluorapatite

    SciTech Connect

    Lexa, D.

    1999-01-01

    A lithium-beryllium-substituted fluorapatite, Li{sub 0.50}Be{sub 0.25}Ca{sub 4.50}(PO{sub 4}){sub 3}F, has been prepared by means of a high-temperature reaction between lithium beryllium fluoride, Li{sub 2}BeF{sub 4}, and tricalcium phosphate, Ca{sub 3}(PO{sub 4}){sub 2}. This material has potential application as a waste form for radioactive and toxic fluoride salts. Monitoring of the reaction progress by differential scanning calorimetry indicated that the reaction was initiated by melting of the fluoride salt and that it was fast and complete. While reactive sintering of lithium beryllium fluoride with tricalcium phosphate led to a rather porous product, melting of the reactants with subsequent solidification readily produced a substituted fluorapatite with a near-theoretical bulk density.

  12. Fluoride in diet

    MedlinePlus

    ... broken through the gums have changes in the enamel that covers the teeth. Faint white lines or ... regarding fluoride intake from reconstituted infant formula and enamel fluorosis: a report of the American Dental Association ...

  13. Other Fluoride Products

    MedlinePlus

    ... relatively infrequent, generally at 3 to 12–month intervals, fluoride gel poses little risk for dental fluorosis, ... many hours. Varnishes must be reapplied at regular intervals with at least 2 applications per year required ...

  14. How Does Fluoride Work?

    MedlinePlus

    ... Fluoride is a natural element found in the earth's crust as well as in water and air. ... Activity: Teeth What Are Dentures? Contact Us Print Resources Send to a Friend Permissions Guidelines About KidsHealth ...

  15. Surfactant-assisted hydrothermal crystallization of nanostructured lithium metasilicate (Li{sub 2}SiO{sub 3}) hollow spheres: (I) Synthesis, structural and microstructural characterization

    SciTech Connect

    Ortiz-Landeros, J.

    2011-05-15

    Lithium metasilicate (Li{sub 2}SiO{sub 3}) was successfully synthesized using a hydrothermal process in the presence of different surfactants with cationic, non-ionic and anionic characters. The samples obtained were compared to a sample prepared by the conventional solid-state reaction method. The structural and microstructural characterizations of different Li{sub 2}SiO{sub 3} powders were performed using various techniques. Diffraction analyses revealed the successful crystallization of pure Li{sub 2}SiO{sub 3} single phase by hydrothermal technique, even without further heat-treatments and independent of the surfactant used. Electron microscopy analyses revealed that Li{sub 2}SiO{sub 3} powders were composed of uniform micrometric particles with a hollow sphere morphology and nanostructured walls. Finally, different thermal analyses showed that Li{sub 2}SiO{sub 3} samples preserved their structure and microstructure after further thermal treatments. Specific aspects regarding the formation mechanism of the spherical aggregates under hydrothermal conditions are discussed, and there is a special emphasis on the effect of the synthesis pathway on the morphological characteristics. -- Graphical abstract: Li{sub 2}SiO{sub 3} was synthesized using a hydrothermal process in the presence of different surfactants. Li{sub 2}SiO{sub 3} powders were composed of uniform micrometric particles with a hollow sphere morphology and nanostructured walls. Display Omitted Highlights: {yields} Pure Li{sub 2}SiO{sub 3} was synthesized by the hydrothermal method. {yields} Surfactant addition produced microstructural and morphological variations. {yields} TEM reveled the generation of nanostructured hollow spheres.

  16. Eu{sub 3}F{sub 4}S{sub 2}: Synthesis, crystal structure, and magnetic properties of the mixed-valent europium(II,III) fluoride sulfide EuF{sub 2}.(EuFS){sub 2}

    SciTech Connect

    Grossholz, Hagen; Hartenbach, Ingo; Kotzyba, Gunter; Poettgen, Rainer; Trill, Henning; Mosel, Bernd D.; Schleid, Thomas

    2009-11-15

    Using the method to synthesize rare-earth metal(III) fluoride sulfides MFS (M=Y, La, Ce-Lu), in some cases we were able to obtain mixed-valent compounds such as Yb{sub 3}F{sub 4}S{sub 2} instead. With Eu{sub 3}F{sub 4}S{sub 2} another isotypic representative has now been synthesized. Eu{sub 3}F{sub 4}S{sub 2} (tetragonal, I4/mmm, a=400.34(2), c=1928.17(9) pm, Z=2) is obtained from the reaction of metallic europium, elemental sulfur, and europium trifluoride in a molar ratio of 5:6:4 within seven days at 850 deg. C in silica-jacketed gas-tightly sealed platinum ampoules. The single-phase product consists of black plate-shaped single crystals with a square cross section, which can be obtained from a flux using equimolar amounts of NaCl as fluxing agent. The crystal structure is best described as an intergrowth structure, in which one layer of CaF{sub 2}-type EuF{sub 2} is followed by two layers of PbFCl-type EuFS when sheeted parallel to the (001) plane. Accordingly there are two chemically and crystallographically different europium cations present. One of them (Eu{sup 2+}) is coordinated by eight fluoride anions in a cubic fashion, the other one (Eu{sup 3+}) exhibits a monocapped square antiprismatic coordination sphere with four F{sup -} and five S{sup 2-} anions. Although the structural ordering of the different charged europium cations is plausible, a certain amount of charge delocalization with some polaron activity has to take place, which is suggested by the black color of the title compound. Temperature dependent magnetic susceptibility measurements of Eu{sub 3}F{sub 4}S{sub 2} show Curie-Weiss behavior with an experimental magnetic moment of 8.19(5) mu{sub B} per formula unit and a paramagnetic Curie temperature of 0.3(2) K. No magnetic ordering is observed down to 4.2 K. In accordance with an ionic formula splitting like (Eu{sup II})(Eu{sup III}){sub 2}F{sub 4}S{sub 2} only one third of the europium centers in Eu{sub 3}F{sub 4}S{sub 2} carry permanent

  17. Process for converting magnesium fluoride to calcium fluoride

    DOEpatents

    Kreuzmann, A.B.; Palmer, D.A.

    1984-12-21

    This invention is a process for the conversion of magnesium fluoride to calcium fluoride whereby magnesium fluoride is decomposed by heating in the presence of calcium carbonate, calcium oxide or calcium hydroxide. Magnesium fluoride is a by-product of the reduction of uranium tetrafluoride to form uranium metal and has no known commercial use, thus its production creates a significant storage problem. The advantage of this invention is that the quality of calcium fluoride produced is sufficient to be used in the industrial manufacture of anhydrous hydrogen fluoride, steel mill flux or ceramic applications.

  18. Lithium nephrotoxicity.

    PubMed

    Oliveira, Jobson Lopes de; Silva Júnior, Geraldo Bezerra da; Abreu, Krasnalhia Lívia Soares de; Rocha, Natália de Albuquerque; Franco, Luiz Fernando Leonavicius G; Araújo, Sônia Maria Holanda Almeida; Daher, Elizabeth de Francesco

    2010-01-01

    Lithium has been widely used in the treatment of bipolar disorder. Its renal toxicity includes impaired urinary concentrating ability and natriuresis, renal tubular acidosis, tubulointerstitial nephritis progressing to chronic kidney disease and hypercalcemia. The most common adverse effect is nephrogenic diabetes insipidus, which affects 20-40% of patients within weeks of lithium initiation. Chronic nephropathy correlates with duration of lithium therapy. Early detection of renal dysfunction should be achieved by rigorous monitoring of patients and close collaboration between psychiatrists and nephrologists. Recent experimental and clinical studies begin to clarify the mechanisms by which lithium induces changes in renal function. The aim of this study was to review the pathogenesis, clinical presentation, histopathological aspects and treatment of lithium-induced nephrotoxicity.

  19. The future of water fluoridation and other systemic fluorides.

    PubMed

    Horowitz, H S

    1990-02-01

    School and community water fluoridation, salt fluoridation, and use of dietary fluoride supplements have abundant scientific support as effective caries-preventive methods. Because caries has declined greatly in many developed countries from use of topical fluorides, the absolute caries reduction will be considerably smaller when systemic fluoride methods are implemented now than it was 20 to 40 years ago. For countries with most of the population living in cities with communal water supplies, community fluoridation is the most logical approach from the standpoints of cost-effectiveness and total caries-preventive impact. In countries with a mostly rural population without central water supplies, salt fluoridation is more practical. Dietary fluoride supplements can be recommended only for regions where neither water fluoridation nor salt fluoridation is possible, or as a temporary measure. Although divergent views exist concerning the relative caries-preventive effects of pre-eruptive and post-eruptive fluoride administration, the effectiveness of systemic fluoride methods for preventing dental caries remains unchallenged. Persuasive scientific and public health arguments exist to justify implementing and sustaining their use. The future of these methods will be influenced by the findings of new clinical and epidemiological research. Social, political, economic, and educational factors will be of equal, if not greater, importance. Perceptions of the current severity of dental caries as a health problem and of risks associated with preventing the problem may affect the future uses of systemic fluorides more than will recommendations of scientists.

  20. Morphology memory but reconstructing crystal structure: porous hexagonal GeO2 nanorods for rechargeable lithium-ion batteries.

    PubMed

    Wei, Wei; Jia, Fangfang; Qu, Peng; Huang, Zhongning; Wang, Hua; Guo, Lin

    2017-03-17

    Hexagonal GeO2, with high theoretical reversible capacity and low operating voltage, is regarded as a promising anode material for Li ion batteries. Being similar to other alloy type anode materials, the practical application of GeO2 is confronted with large volume change and fast capacity fading during lithiation/delithiation cycles. Constructing unique GeO2 nanostructures is proposed as an effective strategy to address this issue of fast capacity degradation. However, the controllable synthesis of GeO2 nanomaterials is challenged due to the fast hydrolysis of Ge precursors in aqueous solution. In this work, we report a simple strategy to synthesize GeO2 nanorods by using orthorhombic Ca2Ge7O16 nanorods as the sacrificial template with HNO3 as the etching agent. With the morphology memory of orthorhombic Ca2Ge7O16 nanorods, the as-prepared porous hexagonal GeO2 nanorods exhibit excellent electrochemical performance with a high capacity of 747 mA h g(-1) after 50 cycles, which should be attributed to the porous and one dimensional nanostructure of GeO2 nanorods. This facile 'morphology memory but restructuring crystal structure' method could be extended to the controllable preparation of other GeO2 nanostructures, and achieve more efficient anode materials.

  1. Temperature insensitive, high-power cascaded optical parametric oscillator based on an aperiodically poled lithium niobate crystal.

    PubMed

    Chen, Tao; Jiang, Peipei; Wu, Bo; Shu, Rong; Hu, Chengzhi; Shen, Yonghang

    2014-11-03

    We report a novel temperature insensitive, APMgLN-based, high-power cascaded optical parametric oscillator (OPO) pumped by an Ytterbium-doped fiber laser. A monolithic APMgLN crystal was designed to compensate the phase mismatches for the nonlinear conversions from the pump to the idler and the primary signal to the idler simultaneously in a wide temperature range. Efficient parametric conversion with pump-to-idler conversion efficiency over 15% and slope efficiency higher than 20% was realized from 25 °C to 55 °C. The idler wavelength was down-shifted from 3.82 μm to 3.78 μm accordingly during the temperature rise. The highest idler power of 4.1 W at 3.8 μm under the pump power of 26.5 W was recorded which was improved by ~32% in pump-to-idler conversion efficiency when compared with the PPMgLN-based conventional OPO, in which the highest idler output power was 3.1W under the same pump and thermal condition.

  2. A 3.90 V iron-based fluorosulphate material for lithium-ion batteries crystallizing in the triplite structure

    SciTech Connect

    Barpanda, P.; Ati, M.; Melot, B.C.; Rousse, G.; Chotard, J-N.; Doublet, M-L.; Sougrati, M.T.; Corr, S.A.; Jumas, J-C.; Tarascon, J-M.

    2011-11-17

    Li-ion batteries have empowered consumer electronics and are now seen as the best choice to propel forward the development of eco-friendly (hybrid) electric vehicles. To enhance the energy density, an intensive search has been made for new polyanionic compounds that have a higher potential for the Fe{sup 2+}/Fe{sup 3+} redox couple. Herein we push this potential to 3.90 V in a new polyanionic material that crystallizes in the triplite structure by substituting as little as 5 atomic per cent of Mn for Fe in Li(Fe{sub 1-{delta}}Mn{delta})SO{sub 4}F. Not only is this the highest voltage reported so far for the Fe{sup 2+}/Fe{sup 3+} redox couple, exceeding that of LiFePO{sub 4} by 450 mV, but this new triplite phase is capable of reversibly releasing and reinserting 0.7-0.8 Li ions with a volume change of 0.6% (compared with 7 and 10% for LiFePO{sub 4} and LiFeSO{sub 4}F respectively), to give a capacity of {approx}125 mA h g{sup -1}.

  3. Fluoride content of infant foods.

    PubMed

    Steele, Jaime L; Martinez-Mier, E Angeles; Sanders, Brian J; Jones, James E; Jackson, Richard D; Soto-Rojas, Armando E; Tomlin, Angela M; Eckert, George J

    2014-01-01

    Excessive fluoride consumption during the first 2 years of life is associated with an increased risk of dental fluorosis. Estimates of fluoride intake from various sources may aid in determining a child's risk for developing fluorosis. This study sought to assess the fluoride content of commercially available foods for infants, and to guide dentists who are advising parents of young children about fluoride intake. Three samples each of 20 different foods (including fruits and vegetables, as well as chicken, turkey, beef/ham, and vegetarian dinners) from 3 manufacturers were analyzed (in duplicate) for their fluoride content. Among the 360 samples tested, fluoride concentration ranged from 0.007-4.13 μg fluoride/g food. All foods tested had detectable amounts of fluoride. Chicken products had the highest mean levels of fluoride, followed by turkey products. Consuming >1 serving per day of the high fluoride concentration products in this study would place children over the recommended daily fluoride intake. Fluoride from infant foods should be taken into account when determining total daily fluoride intake.

  4. The effect of fluoride on the developing tooth.

    PubMed

    Robinson, C; Connell, S; Kirkham, J; Brookes, S J; Shore, R C; Smith, A M

    2004-01-01

    This review aims to outline the effects of fluoride on the biological processes involved in the formation of tooth tissues, particularly dental enamel. Attention has been focused on mechanisms which, if compromised, could give rise to dental fluorosis. The literature is extensive and often confusing but a much clearer picture is emerging based on recent more detailed knowledge of odontogenesis. Opacity, characteristic of fluorotic enamel, results from incomplete apatite crystal growth. How this occurs is suggested by other changes brought about by fluoride. Matrix proteins, associated with the mineral phase, normally degraded and removed to permit final crystal growth, are to some extent retained in fluorotic tissue. Fluoride and magnesium concentrations increase while carbonate is reduced. Crystal surface morphology at the nano-scale is altered and functional ameloblast morphology at the maturation stage also changes. Fluoride incorporation into enamel apatite produces more stable crystals. Local supersaturation levels with regard to the fluoridated mineral will also be elevated facilitating crystal growth. Such changes in crystal chemistry and morphology, involving stronger ionic and hydrogen bonds, also lead to greater binding of modulating matrix proteins and proteolytic enzymes. This results in reduced degradation and enhanced retention of protein components in mature tissue. This is most likely responsible for porous fluorotic tissue, since matrix protein removal is necessary for unimpaired crystal growth. To resolve the outstanding problems of the role of cell changes and the precise reasons for protein retention more detailed studies will be required of alterations to cell function, effect on specific protein species and the nano-chemistry of the apatite crystal surfaces.

  5. Permeability and fluoride release of lining materials containing amine fluorides.

    PubMed

    Nordbö, H; Eriksen, H M

    1976-11-01

    The addition of amine fluorides to a copal recin (Copalite) and a chlorine caoutchouc varnish (Pergut S-40) has been studied. The permeability of Copalite films was only slightly increased whereas the excellent film-forming qualities of Pergut S-40 were destroyed by the addition of fluorides. A high fluoride release was found initially from test films of the materials but within 2-3 weeks a decrease to very low fluoride levels was observed.

  6. MOLTEN FLUORIDE NUCLEAR REACTOR FUEL

    DOEpatents

    Barton, C.J.; Grimes, W.R.

    1960-01-01

    Molten-salt reactor fuel compositions consisting of mixtures of fluoride salts are reported. In its broadest form, the composition contains an alkali fluoride such as sodium fluoride, zirconium tetrafluoride, and a uranium fluoride, the latter being the tetrafluoride or trifluoride or a mixture of the two. An outstanding property of these fuel compositions is a high coeffieient of thermal expansion which provides a negative temperature coefficient of reactivity in reactors in which they are used.

  7. [Lithium nephropathy].

    PubMed

    Kaczmarczyk, Ireneusz; Sułowicz, Władysław

    2013-01-01

    Lithium salts are the first-line drug therapy in the treatment of uni- and bipolar disorder since the sixties of the twentieth century. In the mid-70s, the first information about their nephrotoxicity appeared. Lithium salts have a narrow therapeutic index. Side effects during treatment are polyuria, polydipsia and nephrogenic diabetes insipidus. Accidental intoxication can cause acute renal failure requiring renal replacement therapy while receiving long-term lithium salt can lead to the development of chronic kidney disease. The renal biopsy changes revealed a type of chronic tubulointerstitial nephropathy. The imaging studies revealed the presence of numerous symmetric microcysts. Care of the patient receiving lithium should include regular determination of serum creatinine, creatinine clearance and monitoring of urine volume. In case of deterioration of renal function reducing the dose should be considered.

  8. Lithium toxicity

    MedlinePlus

    ... Lithonate Note: Lithium is also commonly found in batteries, lubricants, high performance metal alloys, and soldering supplies. ... Kidney failure Memory problems Movement disorders Problems ... your body Psychosis (disturbed thought processes, unpredictable ...

  9. Synthesis of SnO2 versus Sn crystals within N-doped porous carbon nanofibers via electrospinning towards high-performance lithium ion batteries.

    PubMed

    Wang, Hongkang; Lu, Xuan; Li, Longchao; Li, Beibei; Cao, Daxian; Wu, Qizhen; Li, Zhihui; Yang, Guang; Guo, Baolin; Niu, Chunming

    2016-04-14

    The design of tin-based anode materials (SnO2 or Sn) has become a major concern for lithium ion batteries (LIBs) owing to their different inherent characteristics. Herein, particulate SnO2 or Sn crystals coupled with porous N-doped carbon nanofibers (denoted as SnO2/PCNFs and Sn/PCNFs, respectively) are fabricated via the electrospinning method. The electrochemical behaviors of both SnO2/PCNFs and Sn/PCNFs are systematically investigated as anodes for LIBs. When coupled with porous carbon nanofibers, both SnO2 nanoparticles and Sn micro/nanoparticles display superior cycling and rate performances. SnO2/PCNFs and Sn/PCNFs deliver discharge capacities of 998 and 710 mA h g(-1) after 140 cycles (at 100, 200, 500 and 1000 mA g(-1) each for 10 cycles and then 100 cycles at 100 mA g(-1)), respectively. However, the Sn/PCNF electrodes show better cycling stability at higher current densities, delivering higher discharge capacities of 700 and 550 mA h g(-1) than that of SnO2/PCNFs (685 and 424 mA h g(-1)) after 160 cycles at 200 and 500 mA g(-1), respectively. The different superior electrochemical performance is attributed to the introduction of porous N-doped carbon nanofibers and their self-constructed networks, which, on the one hand, greatly decrease the charge-transfer resistance due to the high conductivity of N-doped carbon fibers; on the other hand, the porous carbon nanofibers with numerous voids and flexible one-dimensional (1D) structures efficiently alleviate the volume changes of SnO2 and Sn during the Li-Sn alloying-dealloying processes. Moreover, the discussion of the electrochemical behaviors of SnO2vs. Sn would provide new insights into the design of tin-based anode materials for practical applications, and the current strategy demonstrates great potential in the rational design of metallic tin-based anode materials.

  10. Synthesis and effect of electrode heat-treatment on the superior lithium storage performance of Co3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Jingjing; Huang, Tao; Yu, Aishui

    2015-01-01

    Single-crystal Co3O4 nanoparticles are produced via a novel lysine-assisted hydrothermal process. When used as anode materials for lithium-ion batteries, a heat-treatment process is first introduced to decrease the initial irreversible loss and enhance the cyclability of Co3O4 nanoparticle-based electrodes using a polyvinylidene fluoride (PVDF) binder. Heat-treated electrodes exhibit improved lithium storage properties relative to those that are unheated. In particular, Co3O4 electrodes heated at 200 °C have the highest capacity and best reversibility: 1000 mA h g-1 with 95.2% capacity retention after 170 cycles at a current density of 100 mA g-1. Even when cycled at a high rate of 1000 mA g-1, a reversible capacity up to 600 mA h g-1 can still be maintained after 500 cycles. These improvements are explained based on the results from thermal analysis, transmission electron microscopy, scanning electron microscopy, nanoscratch tests, and electrochemical impedance spectroscopy measurements. Heat treatment not only improves binder distribution and adhesion to both Co3O4 particles and the substrate but also ensures high interfacial conductivity and keeps the active material particles and carbon black electrically connected, thereby leading to superior electrochemical performance. The results suggest that the heat-treated Co3O4 electrode may be a promising anode for next-generation lithium-ion batteries.

  11. X-ray diffraction studies of phase transformations in heavy-metal fluoride glasses

    NASA Technical Reports Server (NTRS)

    Bansal, N. P.; Doremus, R. H.

    1985-01-01

    Powder X-ray diffraction and differential scanning calorimetry studies of the crystallization properties of five ZrF4-based glass compositions have indicated that the crystalline phase in Zr-Ba-La-Pb fluoride glass is beta-BaZrF6; no such identification of crystal phases was obtainable, however, for the other glasses. Reversible polymorphic phase transformations occur in Zr-Ba-La-Li and Zr-Ba-La-Na fluoride glasses, upon heating to higher temperatures.

  12. Multiple Fluorine-Substituted Phosphate Germanium Fluorides and Their Thermal Stabilities.

    PubMed

    Huang, Xia; Liu, Biao; Zhuang, Rong-Chuan; Pan, Yuanming; Mi, Jin-Xiao; Huang, Ya-Xi

    2016-12-05

    Anhydrous compounds are crucially important for many technological applications, such as achieving high performance in lithium/sodium cells, but are often challenging to synthesize under hydrothermal conditions. Herein we report that a modified solvo-/hydro-fluorothermal method with fluoride-rich and water-deficient condition is highly effective for synthesizing anhydrous compounds by the replacement of hydroxyl groups and water molecules with fluorine. Two anhydrous phosphate germanium fluorides, namely, Na3[GeF4(PO4)] and K4[Ge2F9(PO4)], with chainlike structures involving multiple fluorine substitutions, were synthesized using the modified solvo-/hydro-fluorothermal method. The crystal structure of Na3[GeF4(PO4)] is constructed by the common single chains ∞(1){[GeF4(PO4)](3-)} built from alternating GeO2F4 octahedra and PO4 tetrahedra. For K4[Ge2F9(PO4)], it takes the same single chain in Na3[GeF4(PO4)] as the backbone but has additional flanking GeOF5 octahedra via an O-corner of the PO4 groups, resulting in a dendrite zigzag single chain ∞(1){[Ge2F9(PO4)](4-)}. The multiple fluorine substitutions in these compounds not only force them to adopt the low-dimensional structures because of the "tailor effect" but also improve their thermal stabilities. The thermal behavior of Na3[GeF4(PO4)] was investigated by an in situ powder X-ray diffraction experiment from room temperature to 700 °C. The modified solvo-/hydro-fluorothermal method is also shown to be effective in producing the most germanium-rich compounds in the germanophosphate system.

  13. Stabilization of Th{sup 3+} ions into mixed-valence thorium fluoride

    SciTech Connect

    Dubois, Marc; Dieudonne, Belto; Mesbah, Adel; Bonnet, Pierre; El-Ghozzi, Malika; Renaudin, Guillaume; Avignant, Daniel

    2011-01-15

    The unusual oxidation state +3 of the thorium has been stabilized into a lithium containing non-stoichiometric mixed-valence (III/IV) thorium fluorinated phase with formula Li{sub 2+x}Th{sub 12}F{sub 50} (0crystal X-ray diffraction and high resolution synchrotron powder diffraction. In these phases, the Li{sup +} ions can be divided into two groups and are located either in locked positions or in open channels of the three dimensional framework. The amount of Li{sup +} ions in open channels can be variable, so that the afore mentioned single phase may be considered as an insertion compound. The Li{sup +} insertion is accompanied by the simultaneous reduction of a part of the Th{sup 4+} ions, resulting in a mixed-valence III/IV thorium fluoride. The electrochemical insertion of Li{sup +} ions into the open channels of the host matrix has been carried out at 60 {sup o}C, using an alkylcarbonate PC-LiClO{sub 4} 1 M electrolyte. The Li{sup +} and Th{sup 3+} contents, both in the starting composition and the Li{sup +} inserted ones, were investigated by high resolution solid state {sup 7}Li NMR and EPR, respectively. -- Graphical abstract: Electrochemical insertion of Li{sup +} ions into mixed-valence III/IV thorium fluoride and EPR spectra for the raw and inserted compounds. Display Omitted

  14. Small molecule fluoride toxicity agonists.

    PubMed

    Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

    2015-04-23

    Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride.

  15. Small Molecule Fluoride Toxicity Agonists

    PubMed Central

    Nelson1, James W.; Plummer, Mark S.; Blount, Kenneth F.; Ames, Tyler D.; Breaker, Ronald R.

    2015-01-01

    SUMMARY Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch-reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. PMID:25910244

  16. Heavy Metal Fluoride Glasses.

    DTIC Science & Technology

    1987-04-01

    relatively low refractive Indices in the visible range of about 1.5-1.9 and fairly good chemical resistance towards water and weak acids. Their...particularly interesting to compare with crystalline fluorides (Refs. 25, 37) such as 7800 spinel-type Li2NiF4 ; 7700 rutile-type NiF2 ; 7500 perovskite-type

  17. Ferrimyoglobin-Fluoride.

    ERIC Educational Resources Information Center

    Russo, Steven O.; Hanania, George I. H.

    1990-01-01

    Described is an experiment which is designed to investigate the reaction of the protein ferrimyoglobin with fluoride. The activity uses readily available apparatus and the technique of optical absorbance for measurement of concentrations. Experimental design, procedures, and treatment of the equilibrium data are detailed. (CW)

  18. Fluorine (soluble fluoride)

    Integrated Risk Information System (IRIS)

    Fluorine ( soluble fluoride ) ; CASRN 7782 - 41 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for No

  19. Advantages of liquid fluoride thorium reactor in comparison with light water reactor

    NASA Astrophysics Data System (ADS)

    Bahri, Che Nor Aniza Che Zainul; Majid, Amran Ab.; Al-Areqi, Wadeeah M.

    2015-04-01

    Liquid Fluoride Thorium Reactor (LFTR) is an innovative design for the thermal breeder reactor that has important potential benefits over the traditional reactor design. LFTR is fluoride based liquid fuel, that use the thorium dissolved in salt mixture of lithium fluoride and beryllium fluoride. Therefore, LFTR technology is fundamentally different from the solid fuel technology currently in use. Although the traditional nuclear reactor technology has been proven, it has perceptual problems with safety and nuclear waste products. The aim of this paper is to discuss the potential advantages of LFTR in three aspects such as safety, fuel efficiency and nuclear waste as an alternative energy generator in the future. Comparisons between LFTR and Light Water Reactor (LWR), on general principles of fuel cycle, resource availability, radiotoxicity and nuclear weapon proliferation shall be elaborated.

  20. Advantages of liquid fluoride thorium reactor in comparison with light water reactor

    SciTech Connect

    Bahri, Che Nor Aniza Che Zainul Majid, Amran Ab.; Al-Areqi, Wadeeah M.

    2015-04-29

    Liquid Fluoride Thorium Reactor (LFTR) is an innovative design for the thermal breeder reactor that has important potential benefits over the traditional reactor design. LFTR is fluoride based liquid fuel, that use the thorium dissolved in salt mixture of lithium fluoride and beryllium fluoride. Therefore, LFTR technology is fundamentally different from the solid fuel technology currently in use. Although the traditional nuclear reactor technology has been proven, it has perceptual problems with safety and nuclear waste products. The aim of this paper is to discuss the potential advantages of LFTR in three aspects such as safety, fuel efficiency and nuclear waste as an alternative energy generator in the future. Comparisons between LFTR and Light Water Reactor (LWR), on general principles of fuel cycle, resource availability, radiotoxicity and nuclear weapon proliferation shall be elaborated.

  1. Navy Lithium Battery Safety

    DTIC Science & Technology

    2010-07-14

    lithium -sulfur dioxide (Li-SO2), lithium - thionyl chloride (Li- SOCL2), and lithium -sulfuryl chloride (Li-S02CL2...and 1980’s with active primary cells: Lithium -sulfur dioxide (Li-SO2) Lithium - thionyl chloride (Li-SOCL2) Lithium -sulfuryl chloride (Li-S0 CL ) 2 2...DISTRIBUTION A. Approved for public release; distribution unlimited. NAVY LITHIUM BATTERY SAFETY John Dow1 and Chris Batchelor2 Naval

  2. Mapping of fluoride endemic areas and assessment of fluoride exposure.

    PubMed

    Viswanathan, Gopalan; Jaswanth, A; Gopalakrishnan, S; Siva ilango, S

    2009-02-15

    The prevalence of fluorosis is mainly due to the consumption of more fluoride through drinking water. It is necessary to find out the fluoride endemic areas to adopt remedial measures to the people on the risk of fluorosis. The objectives of this study are to estimate the fluoride exposure through drinking water from people of different age group and to elucidate the fluoride endemic areas through mapping. Assessment of fluoride exposure was achieved through the estimation fluoride level in drinking water using fluoride ion selective electrode method. Google earth and isopleth technique were used for mapping of fluoride endemic areas. From the study it was observed that Nilakottai block of Dindigul district in Tamil Nadu is highly fluoride endemic. About 88% of the villages in this block have fluoride level more than the prescribed permissible limit in drinking water. Exposure of fluoride among different age groups was calculated in this block, which comprises 32 villages. The maximum estimated exposure doses were 0.19 mg/kg/day for infants, 0.17 mg/kg/day for children and 0.10 mg/kg/day for adults. When compared with adequate intake of minimal safe level exposure dose of 0.01 mg/kg/day for infants and 0.05 mg/kg/day for other age groups, a health risk due to fluorosis to the people in Nilakottai block has become evident. From the results, the people in Nilakottai block are advised to consume drinking water with fluoride level less than 1 mg/l. It has been recommended to the government authorities to take serious steps to supply drinking water with low fluoride concern for the fluorosis affected villages.

  3. Dynamics of photo-induced changes in the elastic characteristics of lithium niobate crystals doped with Jahn-Teller Fe2+ ions

    NASA Astrophysics Data System (ADS)

    Golenishchev-Kutuzov, A. V.; Golenishchev-Kutuzov, V. A.; Kalimullin, R. I.; Semennikov, A. V.

    2017-02-01

    The effect of admixture Jahn-Teller Fe2+ ions on the elastic characteristics of lithium niobate was studied. The appearance of photostrains and a change in elastic moduli under the influence of laser radiation was established, thus enabling the creation of device elements with optically controlled elastic characteristics.

  4. Effect of water fluoridation on the development of medial vascular calcification in uremic rats.

    PubMed

    Martín-Pardillos, Ana; Sosa, Cecilia; Millán, Ángel; Sorribas, Víctor

    2014-04-06

    Public water fluoridation is a common policy for improving dental health. Fluoride replaces the hydroxyls of hydroxyapatite, thereby improving the strength of tooth enamel, but this process can also occur in other active calcifications. This paper studies the effects of water fluoridation during the course of vascular calcification in renal disease. The effect of fluoride was studied in vitro and in vivo. Rat aortic smooth muscle cells were calcified with 2mM Pi for 5 days. Fluoride concentrations of 5-10 μM--similar to those found in people who drink fluoridated water--partially prevented calcification, death, and osteogene expression in vitro. The anticalcifying mechanism was independent of cell activity, matrix Gla protein, and fetuin A expressions, and it exhibited an IC50 of 8.7 μM fluoride. In vivo, however, fluoridation of drinking water at 1.5mg/L (concentration recommended by the WHO) and 15 mg/L dramatically increased the incipient aortic calcification observed in rats with experimental chronic kidney disease (CKD, 5/6-nephrectomy), fed a Pi-rich fodder (1.2% Pi). Fluoride further declined the remaining renal function of the CKD animals, an effect that most likely overwhelmed the positive effect of fluoride on calcification in vitro. Ultrastructural analysis revealed that fluoride did not modify the Ca/P atomic ratio, but it was incorporated into the lattice of in vivo deposits. Fluoride also converted the crystallization pattern from plate to rode-like structures. In conclusion, while fluoride prevents calcification in vitro, the WHO's recommended concentrations in drinking water become nephrotoxic to CKD rats, thereby aggravating renal disease and making media vascular calcification significant.

  5. Space-charge at the lithium-lithium chloride interface

    NASA Astrophysics Data System (ADS)

    Jamnik, J.; Gaberscek, M.; Meden, A.; Pejovnik, S.

    1991-06-01

    The electrical properties of the passive layer formed on lithium as the product of the corrosion reaction in thionyl chloride are discussed. The passive layer is regarded as a thin layer of an ionic crystal placed between two party blocking electrodes (i.e., lithium and liquid electrolyte). After a short review of thermodynamic properties of the system, a model for description of the electric properties of the static space-charge regions is presented. On this basis, a comment on and partial reinterpretation of impedance measurements of the passive layer is given. The suggested approach leads to the conclusion that the quality of Li/SOCl2 batteries decisively depends on the properties of the lithium passive layer interface. Finally, experiments to confirm the model are suggested.

  6. Health Effects Associated with Water Fluoridation.

    ERIC Educational Resources Information Center

    Richmond, Virginia L.

    1979-01-01

    Discussion is presented concerning fluoridation of water supplies. Correlation between fluoride in drinking water and improved dental health is reviewed. Relationship is expressed between fluoridation and reduced tooth decay. Use of fluoride in treating skeletal disorders is discussed. Author advocates fluoridating water supplies. (SA)

  7. 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.

  8. Plasma and Brain Pharmacokinetics of Previously Unexplored Lithium Salts

    PubMed Central

    Smith, Adam J.; Kim, Seol-Hee; Tan, Jun; Sneed, Kevin B.; Sanberg, Paul R.; Borlongan, Cesar V.; Shytle, R. Douglas

    2014-01-01

    Despite its narrow therapeutic window, lithium is still regarded as the gold standard comparator and benchmark treatment for mania. Recent attempts to find new drugs with similar therapeutic activities have yielded new chemical entities. However, these potential new drugs have yet to match the many bioactivities attributable to lithium's efficacy for the treatment of neuropsychiatric diseases. Consequently, an intense effort for re-engineering lithium therapeutics using crystal engineering is currently underway. We sought to improve the likelihood of success of these endeavors by evaluating the pharmacokinetics of previously unexplored lithium salts with organic anions (lithium salicylate and lithium lactate). We report that these lithium salts exhibit profoundly different pharmacokinetics compared to the more common FDA approved salt, lithium carbonate, in rats. Remarkably, lithium salicylate produced elevated plasma and brain levels of lithium beyond 48 hours post-dose without the sharp peak that contributes to the toxicity problems of current lithium therapeutics. These findings could be important for the development of the next generation of lithium therapeutics. PMID:25045517

  9. Magnesium fluoride recovery method

    DOEpatents

    Gay, Richard L.; McKenzie, Donald E.

    1989-01-01

    A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag containing the same and having a radioactivity level of at least about 7000 pCi/gm. The slag is ground to a particle size of about 200 microns or less. The ground slag is contacted with an acid under certain prescribed conditions to produce a liquid product and a particulate solid product. The particulate solid product is separated from the liquid and treated at least two more times with acid to produce a solid residue consisting essentially of magnesium fluoride substantially free of uranium and having a residual radioactivity level of less than about 1000 pCi/gm. In accordance with a particularly preferred embodiment of the invention a catalyst and an oxidizing agent are used during the acid treatment and preferably the acid is sulfuric acid having a strength of about 1.0 Normal.

  10. Crystal growth of a series of lithium garnets Ln3Li 5Ta 2O 12 ( Ln=La, Pr, Nd): Structural properties, Alexandrite effect and unusual ionic conductivity

    NASA Astrophysics Data System (ADS)

    Roof, Irina P.; Smith, Mark D.; Cussen, Edmund J.; zur Loye, Hans-Conrad

    2009-02-01

    We report the single crystal structures of a series of lanthanide containing tantalates, Ln3Li 5Ta 2O 12 ( Ln=La, Pr, Nd) that were obtained out of a reactive lithium hydroxide flux. The structures of Ln3Li 5Ta 2O 12 were determined by single crystal X-ray diffraction, where the Li + positions and Li + site occupancies were fixed based on previously reported neutron diffraction data for isostructural compounds. All three oxides crystallize in the cubic space group Ia3¯d (No. 230) with lattice parameters a=12.7735(1), 12.6527(1), and 12.5967(1) Å for La 3Li 5Ta 2O 12, Pr 3Li 5Ta 2O 12, and Nd 3Li 5Ta 2O 12, respectively. A UV-Vis diffuse reflectance spectrum of Nd 3Li 5Ta 2O 12 was collected to explain its unusual Alexandrite-like optical behavior. To evaluate the transport properties of Nd 3Li 5Ta 2O 12, the impedance data were collected in air in the temperature range 300⩽ T(°C)⩽500.

  11. Visualization of lithium ions by annular bright field imaging.

    PubMed

    Oshima, Yoshifumi; Lee, Soyeon; Takayanagi, Kunio

    2016-10-14

    The detection of lithium ions is required for characterization of lithium ion batteries, since the movement of lithium ions in the battery is one of the key ways to improve the performance. Annular bright field (ABF) imaging enables us to visualize individual lithium atomic columns simultaneously with heavy elements. Furthermore, it has been found that the number of lithium ions at the column is countable when the specimen is thin. These results suggest that movement of lithium ions in the material can be observed by taking consecutive ABF images during operation or in situ ABF observation. Actually, the spinel structure of L2V4O crystals was directly observed to be transformed into the defective NaCl structure at the moment when lithium ions were extracted from the original position during electron beam irradiation. We clarify the features of ABF imaging by comparing it with HAADF imaging in order to understand what information can be obtained by ABF imaging directly.

  12. MEASUREMENT OF INFRARED SPECTRA AND CHEMICAL BONDING OF INORGANIC COMPOUNDS.

    DTIC Science & Technology

    CHROMATES, SELENIUM COMPOUNDS, PERMANGANATES, FLUOBORATES , LITHIUM FLUORIDES, BELGIUM...CRYSTAL STRUCTURE, SODIUM CHLORIDE, LITHIUM COMPOUNDS, BARIUM COMPOUNDS, ALKALINE EARTH COMPOUNDS, ALKALI METAL COMPOUNDS, SULFATES, PERCHLORATES

  13. Magnesium batteries: Towards a first use of graphite fluorides

    NASA Astrophysics Data System (ADS)

    Giraudet, Jérôme; Claves, Daniel; Guérin, Katia; Dubois, Marc; Houdayer, Axel; Masin, Francis; Hamwi, André

    Graphite fluorides obtained by fluorination of graphite at room temperature and after a subsequent re-fluorination treatment were characterised by X-ray diffraction and 19F MAS NMR. Their electrochemical performances as cathode materials in magnesium batteries have been investigated. Four different electrolytes (0.5 or 1 M Mg(ClO 4) 2 in ACN, DMSO, PC and THF) were used for these tests. The specific energy and power densities were estimated for all media. A comparison of the performances between lithium and magnesium batteries was realised. The effect, on the electrochemical performances, of a re-fluorination treatment at 250 °C was also studied.

  14. Amelogenin-assisted ex vivo remineralization of human enamel: Effects of supersaturation degree and fluoride concentration.

    PubMed

    Fan, Yuwei; Nelson, James R; Alvarez, Jason R; Hagan, Joseph; Berrier, Allison; Xu, Xiaoming

    2011-05-01

    The formation of organized nanocrystals that resemble enamel is crucial for successful enamel remineralization. Calcium, phosphate and fluoride ions, and amelogenin are important ingredients for the formation of organized hydroxyapatite (HAP) crystals in vitro. However, the effects of these remineralization agents on the enamel crystal morphology have not been thoroughly studied. The objective of this study was to investigate the effects of fluoride ions, supersaturation degree and amelogenin on the crystal morphology and organization of ex vivo remineralized human enamel. Extracted third molars were sliced thin and acid-etched to provide the enamel surface for immersion in different remineralization solutions. The crystal morphology and mineral phase of the remineralized enamel surface were analyzed by field emission-scanning electron microscopy, attenuated total reflection-Fourier transformed infrared and X-ray diffraction. The concentration of fluoride and the supersaturation degree of hydroxyapatite had significant effects on the crystal morphology and crystal organization, which varied from plate-like loose crystals to rod-like densely packed nanocrystal arrays. Densely packed arrays of fluoridated hydroxyapatite nanorods were observed under the following conditions: σ(HAP)=10.2±2.0 with 1.5±0.5 mg l(-1) fluoride and 40±10 μg ml(-1) amelogenin, pH 6.8±0.4. A phase diagram summarizes the conditions that form dense or loose hydroxyapatite nanocrystal structures. This study provides the basis for the development of novel dental materials for caries management.

  15. Amelogenin-assisted ex vivo remineralization of human enamel: effects of supersaturation degree and fluoride concentration

    PubMed Central

    Fan, Yuwei; Nelson, James R.; Alvarez, Jason R.; Hagan, Joseph; Berrier, Allison; Xu, Xiaoming

    2011-01-01

    The formation of organized nanocrystals that resemble enamel is crucial for successful enamel remineralization. Calcium, phosphate and fluoride ions and amelogenin are important ingredients for the formation of organized hydroxyapatite (HAP) crystals in vitro. However, the effects of these remineralization agents on the enamel crystal morphology have not been thoroughly studied. The objective of this study was to investigate the effects of fluoride ions, supersaturation degree and amelogenin on the crystal morphology and organization of ex vivo remineralized human enamel. Extracted third molars were sliced thin and acid-etched to provide the enamel surface for immersion in different remineralization solutions. The crystal morphology and mineral phase of the remineralized enamel surface were analyzed by FE-SEM, ATR-FTIR and XRD. The concentration of fluoride and supersaturation degree of hydroxyapatite had significant effects on the crystal morphology and crystal organization, which varied from plate-like loose crystals to rod-like densely packed nanocrystal arrays. Densely packed arrays of fluoridated hydroxyapatite nanorods were observed under the following conditions: σ(HAP) = 10.2±2.0 with fluoride 1.5±0.5 mg/L and amelogenin 40±10 µg/mL, pH 6.8±0.4. A phase diagram summarized the conditions that form dense or loose hydroxyapatite nanocrystal structures. This study provides the basis for the development of novel dental materials for caries management. PMID:21256987

  16. [Water fluoridation and public health].

    PubMed

    Barak, Shlomo

    2003-11-01

    Fluoridation in Israel was first mooted in 1973 and finally incorporated into law in November 2002 obligating the Ministry of Health to add fluoride to the nation's water supply. Epidemiology studies in the USA have shown that the addition of one part per million of fluoride to the drinking water reduced the caries rate of children's teeth by 50% to 60% with no side effects. Both the WHO in 1994 and the American Surgeon General's report of 2000 declared that fluoridation of drinking water was the safest and most efficient way of preventing dental caries in all age groups and populations. Opposition to fluoridation has arisen from "antifluoridation" groups who object to the "pollution" of drinking water by the addition of chemicals and mass medication in violation of the "Patient's Rights" law and the Basic Law of Human Dignity and Liberty. A higher prevalence of hip fractures in elderly osteoporotic women and osteosarcoma in teenagers has been reported in areas where excess fluoride exists in the drinking water. However, none of the many independent professional committees reviewing the negative aspects of fluoridation have found any scientific evidence associating fluoridation with any ill-effects or health problems. In Israel, where dental treatment is not included in the basket of Health Services, fluoridation is the most efficient and cheapest way of reducing dental disease, especially for the poorer members of the population.

  17. Novel heterocyclic thiosemicarbazones derivatives as colorimetric and "turn on" fluorescent sensors for fluoride anion sensing employing hydrogen bonding.

    PubMed

    Ashok Kumar, S L; Saravana Kumar, M; Sreeja, P B; Sreekanth, A

    2013-09-01

    Two novel heterocyclic thiosemicarbazone derivatives have been synthesized, and characterized, by means of spectroscopic and single crystal X-ray diffraction methods. Their chromophoric-fluorogenic response towards anions in competing solvent dimethyl sulfoxide (DMSO) was studied. The receptor shows selective recognition towards fluoride anion. The binding affinity of the receptors with fluoride anion was calculated using UV-visible and fluorescence spectroscopic techniques.

  18. Radiation effects in fluoride glasses

    NASA Astrophysics Data System (ADS)

    Tanimura, K.; Sibley, W. A.; Suscavage, M.; Drexhage, M.

    1985-12-01

    Radiation-induced defects in Zr-based fluoride glasses have been characterized using optical absorption and electron spin resonance (ESR) techniques. The optical absorption bands due to interstitial fluorine atoms, the F2(-), FC1(-), C12(-) centers, and Zr(3+) centers have been identified by correlating optical absorption and ESR measurements. Polarized bleaching experiments indicate that the hole-type centers, and the Zr(3+) centers have anisotropic defect configurations. X-ray excitation at 14 K generates a broad, asymmetric emission band at 337 nm (3.68 eV), which is assigned to a localized-excited state similar to that for self-trapped excitons in halide crystals. The intensity of the X-ray induced emission provides further evidence that radiolysis defect production occurs in this material. The optical tail of the radiation-induced Zr(3+) absorption affects infrared transmission. Evidence is presented that the CC14 reactive-atmosphere process introduces a significant amount of Cl(-) (about 5 percent) in the glass.

  19. Lithium in 2012

    USGS Publications Warehouse

    Jaskula, B.W.

    2013-01-01

    In 2012, estimated world lithium consumption was about 28 kt (31,000 st) of lithium contained in minerals and compounds, an 8 percent increase from that of 2011. Estimated U.S. consumption was about 2 kt (2,200 st) of contained lithium, the same as that of 2011. The United States was thought to rank fourth in consumption of lithium and remained the leading importer of lithium carbonate and the leading producer of value-added lithium materials. One company, Rockwood Lithium Inc., produced lithium compounds from domestic brine resources near Silver Peak, NV.

  20. Drinking water fluoridation and bone.

    PubMed

    Allolio, B; Lehmann, R

    1999-01-01

    Drinking water fluoridation has an established role in the prevention of dental caries, but may also positively or negatively affect bone. In bone fluoride is incorporated into hydroxylapatite to form the less soluble fluoroapatite. In higher concentrations fluoride stimulates osteoblast activity leading to an increase in cancellous bone mass. As optimal drinking water fluoridation (1 mg/l) is widely used, it is of great interest, whether long-term exposition to artificial water fluoridation has any impact on bone strength, bone mass, and -- most importantly -- fracture rate. Animal studies suggest a biphasic pattern of the effect of drinking water fluoridation on bone strength with a peak strength at a bone fluoride content of 1200 ppm followed by a decline at higher concentrations eventually leading to impaired bone quality. These changes are not paralleled by changes in bone mass suggesting that fluoride concentrations remain below the threshold level required for activation of osteoblast activity. Accordingly, in most epidemiological studies in humans bone mass was not altered by optimal drinking water fluoridation. In contrast, studies on the effect on hip fracture rate gave conflicting results ranging from an increased fracture incidence to no effect, and to a decreased fracture rate. As only ecological studies have been performed, they may be biased by unknown confounding factors -- the so-called ecological fallacy. However, the combined results of these studies indicate that any increase or decrease in fracture rate is likely to be small. It has been calculated that appropriately designed cohort studies to solve the problem require a sample size of >400,000 subjects. Such studies will not be performed in the foreseeable future. Future investigations in humans should, therefore, concentrate on the effect of long-term drinking water fluoridation on bone fluoride content and bone strength.

  1. Crystal growth of a series of lithium garnets Ln{sub 3}Li{sub 5}Ta{sub 2}O{sub 12} (Ln=La, Pr, Nd): Structural properties, Alexandrite effect and unusual ionic conductivity

    SciTech Connect

    Roof, Irina P.; Smith, Mark D.; Cussen, Edmund J.; Loye, Hans-Conrad zur

    2009-02-15

    We report the single crystal structures of a series of lanthanide containing tantalates, Ln{sub 3}Li{sub 5}Ta{sub 2}O{sub 12} (Ln=La, Pr, Nd) that were obtained out of a reactive lithium hydroxide flux. The structures of Ln{sub 3}Li{sub 5}Ta{sub 2}O{sub 12} were determined by single crystal X-ray diffraction, where the Li{sup +} positions and Li{sup +} site occupancies were fixed based on previously reported neutron diffraction data for isostructural compounds. All three oxides crystallize in the cubic space group Ia3-bard (No. 230) with lattice parameters a=12.7735(1), 12.6527(1), and 12.5967(1) A for La{sub 3}Li{sub 5}Ta{sub 2}O{sub 12}, Pr{sub 3}Li{sub 5}Ta{sub 2}O{sub 12}, and Nd{sub 3}Li{sub 5}Ta{sub 2}O{sub 12}, respectively. A UV-Vis diffuse reflectance spectrum of Nd{sub 3}Li{sub 5}Ta{sub 2}O{sub 12} was collected to explain its unusual Alexandrite-like optical behavior. To evaluate the transport properties of Nd{sub 3}Li{sub 5}Ta{sub 2}O{sub 12}, the impedance data were collected in air in the temperature range 300{<=}T(deg. C){<=}500. - Graphical abstract: Crystal structure of garnets Ln{sub 3}Li{sub 5}Ta{sub 2}O{sub 12} (Ln=La, Pr, Nd). TaO{sub 6} polyhedra are shown in yellow and Ln{sup 3+} are shown as light blue spheres. Octahedrally and tetrahedrally coordinated Li{sup +} ions are shown in green and brown, respectively. Oxygen atoms are omitted for clarity.

  2. Fluoride Content in Alcoholic Drinks.

    PubMed

    Goschorska, Marta; Gutowska, Izabela; Baranowska-Bosiacka, Irena; Rać, Monika Ewa; Chlubek, Dariusz

    2016-06-01

    The aim of the study was to determine the role of alcoholic drinks as a potential source of dietary fluoride by means of measuring fluoride levels in selected alcoholic drinks available on the Polish market that are also diverse in terms of the percentage content of ethanol. The study was conducted on 48 types of drinks with low, medium, and high alcohol content available on the Polish market and offered by various manufacturers, both Polish and foreign. Fluoride concentrations in individual samples were measured by potentiometric method with a fluoride ion-selective electrode. The highest fluoride levels were determined in the lowest percentage drinks (less than 10 % v/v ethanol), with the lowest fluoride levels observed in the highest percentage drinks (above 40 % v/v ethanol). In terms of types of alcoholic drinks, the highest fluoride levels were determined in beers and wines, while the lowest levels were observed in vodkas. These data confirm the fact that alcoholic beverages need to be considered as a significant source of fluoride delivered into the body.

  3. WET FLUORIDE SEPARATION METHOD

    DOEpatents

    Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

    1958-11-25

    The separation of U/sup 233/ from thorium, protactinium, and fission products present in neutron-irradiated thorium is accomplished by dissolving the irradiated materials in aqueous nitric acid, adding either a soluble fluoride, iodate, phosphate, or oxalate to precipltate the thorium, separating the precipltate from the solution, and then precipitating uranlum and protactinium by alkalizing the solution. The uranium and protactinium precipitate is removcd from the solution and dissolved in nitric acid. The uranyl nitrate may then be extracted from the acid solution by means of ether, and the protactinium recovered from the aqueous phase.

  4. Caries management with fluoride agents.

    PubMed

    Lam, Anty; Chu, C H

    2012-11-01

    Dental caries is the single most common, chronic oral disease of childhood. It is progressive and cumulative, and becomes more complex over time. The Surgeon General's Report on Oral Health revealed that more than 51 million school hours are lost each year as a result of dental problems. Contemporary caries management philosophy has changed from the traditional surgical approach to a medical model that emphasizes prevention. Among various strategies for caries prevention or reduction, fluoride therapy has been highly promoted. Various in-office and over-the-counter fluoride products are available for caries prevention. Dental professionals should identify and assess the caries risk level of patients and optimize the use of fluorides in caries management. Since multiple sources of fluoride exposure exist, a coordinated approach to fluoride delivery is essential.

  5. Low-temperature crystal structure, specific heat, and dielectric properties of lithium tetraborate Li{sub 2}B{sub 4}O{sub 7}

    SciTech Connect

    Senyshyn, A.; Fuess, H.; Schwarz, B.; Ehrenberg, H.; Lorenz, T.; Adamiv, V. T.; Burak, Ya. V.; Banys, J.; Grigalaitis, R.

    2010-11-15

    Coherent neutron powder diffraction experiments were carried out together with specific heat, dilatometry, and dielectric spectroscopy studies on Li{sub 2}B{sub 4}O{sub 7} enriched with {sup 11}B isotope to 99.3% at low temperatures. Neither traces of phase transformations nor discontinuous changes in physical properties were observed. Negative thermal expansion, anomalous thermal behavior of selected interatomic distances/angles, isotropic displacement parameters on specific sites as well as dielectric constant were discussed in terms of dynamic lithium disorder.

  6. Determination of Stability Constants of Hydrogen and Aluminum Fluorides with a Fluoride-Selective Electrode

    SciTech Connect

    Baumann, E.W.

    2003-01-06

    The ability to directly determine free fluoride ion concentration (or mean activity) simplifies gathering and interpretation of experimental data for studies of metal complexes. In this work, the new lanthanum fluoride electrode was used to measure free fluoride ion in an investigation of the hydrogen-fluoride and aluminum-fluoride systems in NH4NO3.

  7. Urinary Fluoride Concentration in Children with Disabilities Following Long-Term Fluoride Tablet Ingestion

    ERIC Educational Resources Information Center

    Liu, Hsiu-Yueh; Chen, Jung-Ren; Hung, Hsin-Chia; Hsiao, Szu-Yu; Huang, Shun-Te; Chen, Hong-Sen

    2011-01-01

    Urine is the most commonly utilized biomarker for fluoride excretion in public health and epidemiological studies. Approximately 30-50% of fluoride is excreted from urine in children. Urinary fluoride excretion reflects the total fluoride intake from multiple sources. After administering fluoride tablets to children with disabilities, urinary…

  8. Fluorination Induced the Surface Segregation of High Voltage Spinel on Lithium-Rich Layered Cathodes for Enhanced Rate Capability in Lithium Ion Batteries.

    PubMed

    Jin, Yi-Chun; Duh, Jenq-Gong

    2016-02-17

    This study is aimed to explore the effect of fluoride doping and the associated structural transformation on lithium-rich layered cathode materials. The polymeric fluoride source is first adopted for synthesizing lithium intercalated oxide through a newly developed organic precipitation process. A heterostructured spinel/layered composite cathode material is obtained after appreciable fluorination and a superior rate capability is successfully achieved. The fluoride dopant amount and the surface spinel phase are evidenced and systematically examined by various structural spectroscopy and electrochemical analysis. It appears the reversible Ni(2+/4+) redox couple at high voltage regime around 4.8 V because of the formation of spinel LiNi1/2Mn3/2O4 phase. The mechanism of "layer to spinel" phase transformation is discussed in detail.

  9. 49 CFR 173.163 - Hydrogen fluoride.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned...

  10. 49 CFR 173.163 - Hydrogen fluoride.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned...

  11. 49 CFR 173.163 - Hydrogen fluoride.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned...

  12. 49 CFR 173.163 - Hydrogen fluoride.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned...

  13. 49 CFR 173.163 - Hydrogen fluoride.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned...

  14. Lithium-associated hyperthyroidism.

    PubMed

    Siyam, Fadi F; Deshmukh, Sanaa; Garcia-Touza, Mariana

    2013-08-01

    Goiters and hypothyroidism are well-known patient complications of the use of lithium for treatment of bipolar disease. However, the occurrence of lithium-induced hyperthyroidism is a more rare event. Many times, the condition can be confused with a flare of mania. Monitoring through serial biochemical measurement of thyroid function is critical in patients taking lithium. Hyperthyroidism induced by lithium is a condition that generally can be controlled medically without the patient having to discontinue lithium therapy, although in some circumstances, discontinuation of lithium therapy may be indicated. We report on a patient case of lithium-associated hyperthyroidism that resolved after discontinuation of the medication.

  15. Fluoride-induced chronic renal failure.

    PubMed

    Lantz, O; Jouvin, M H; De Vernejoul, M C; Druet, P

    1987-08-01

    Renal fluoride toxicity in human beings is difficult to assess in the literature. Although experimental studies and research on methoxyflurane toxicity have shown frank renal damage, observations of renal insufficiency related to chronic fluoride exposure are scarce. We report a case of fluoride intoxication related to potomania of Vichy water, a highly mineralized water containing 8.5 mg/L of fluoride. Features of fluoride osteosclerosis were prominent and end-stage renal failure was present. The young age of the patient, the long duration of high fluoride intake, and the absence of other cause of renal insufficiency suggest a causal relationship between fluoride intoxication and renal failure.

  16. Protactinium distribution in a fluoride melt in the presence of solid oxide phases

    SciTech Connect

    Alekseev, V.A.; Ziv, V.S.; Morozova, Z.E.

    1989-01-01

    Measurements have been made on protactinium distributions between molten lithium and sodium fluorides and solid lanthanum or zirconium oxides as affected by time, amount of solid, and amount of gas (air of argon) at 1023 K. Protactinium can be extracted quantitatively from LiF-NaF melts by the two oxides. It is found that all the regularities previously reported for actinoid distributions in halide liquids in the presence of oxides apply to protactinium.

  17. Strontium-90 fluoride data sheet

    SciTech Connect

    Fullam, H.T.

    1981-06-01

    This report is a compilation of available data and appropriate literature references on the properties of strontium-90 fluoride and nonradioactive strontium fluoride. The objective of the document is to compile in a single source pertinent data to assist potential users in the development, licensing, and use of /sup 90/SrF/sub 2/-fueled radioisotope heat sources for terrestrial power conversion and thermal applications. The report is an update of the Strontium-90 Fluoride Data Sheet (BNWL-2284) originally issued in April 1977.

  18. Molten fluoride fuel salt chemistry

    SciTech Connect

    Toth, L.M.; Del Cul, G.D.; Dai, S.; Metcalf, D.H.

    1994-09-01

    The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Fission product behavior is described along with processing experience. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known about molten fluoride behavior, processing and recycle of the fuel components is a necessary factor if future systems are to be established.

  19. EPR of radiation defects in lithium-oxyfluoride glass ceramics

    NASA Astrophysics Data System (ADS)

    Fedotovs, A.; Rogulis, U.; Sarakovskis, A.; Dimitrocenko, L.

    2010-11-01

    We studied oxyfluoride composites based on lithium silicate glasses with yttrium fluorides and rare-earth dopants. The electron paramagnetic resonance (EPR) has been used to obtain information about radiation induced defects in these materials. Spectra have been measured before and after X-ray irradiation at room temperature and at liquid nitrogen temperature. Fluoride crystallites within samples were created by means of thermal treatment at specific temperatures. EPR spectra of radiation induced defects in oxyfluoride glass ceramics, in which crystallites have not been yet created, show no explicit hfs interaction of fluorine nuclei. However, in glass ceramics, which already contains fluoride crystallites, the hfs characteristic to fluorine nuclei appears in the EPR spectra. EPR hyperfine structure could be explained within a model of an F-type centre in YF3 crystalline phase.

  20. A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} crystal growth: Fluoride flux synthesis of Na{sub 5}Ln{sub 4}F[GeO{sub 4}]{sub 4} (Ln=Pr, Nd), the first quaternary germanate oxyfluorides

    SciTech Connect

    Latshaw, Allison M.; Wilkins, Branford O.; Morrison, Gregory; Smith, Mark D.; Loye, Hans-Conrad zur

    2016-07-15

    Crystals of Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} were synthesized using a eutectic sodium fluoride, sodium chloride flux. Both compounds crystallize in the tetragonal space group I-4 with lattice parameters of a=12.1173(4) Å and c=5.6795(2) Å (Pr) and of a=12.0642(17) Å and c=5.6674(11) Å (Nd). The structure of the reported compounds is three-dimensional with face and corner sharing lanthanide polyhedra which edge and corner share with isolated germanium tetrahedra. These novel compositions represent the first example of quaternary germanium containing oxyfluorides. - Graphical abstract: Structural image of the first examples of quaternary germanate oxyfluorides. Display Omitted - Highlights: • Molten flux growth of crystals of two lanthanide germanate oxyfluorides. • Expansion of the A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} family into germanate oxyfluorides. • Synthesis of Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4}.

  1. Fluorination utilizing thermodynamically unstable fluorides and fluoride salts thereof

    DOEpatents

    Bartlett, Neil; Whalen, J. Marc; Chacon, Lisa

    2000-12-12

    A method for fluorinating a carbon compound or cationic carbon compound utilizes a fluorination agent selected from thermodynamically unstable nickel fluorides and salts thereof in liquid anhydrous hydrogen fluoride. The desired carbon compound or cationic organic compound to undergo fluorination is selected and reacted with the fluorination agent by contacting the selected organic or cationic organic compound and the chosen fluorination agent in a reaction vessel for a desired reaction time period at room temperature or less.

  2. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    NASA Astrophysics Data System (ADS)

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-08-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4‑δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4‑δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF.

  3. Mechanisms for the Crystallization of ZBLAN

    NASA Technical Reports Server (NTRS)

    Ethridge, Edwin C.; Tucker, Dennis S.; Kaukler, William; Antar, Basil

    2003-01-01

    The objective of this ground based study is to test the hypothesis that shear thinning (the non-Newtonian response of viscosity to shear rate) is a viable mechanism to explain the observation of enhanced glass formation in numerous low-g experiments. In 1-g, fluid motion results from buoyancy forces and surface tension driven convection. This fluid flow will introduce shear in undercooled liquids in 1-g. In low-g it is known that fluid flows are greatly reduced so that the shear rate in fluids can be extremely low. It is believed that some fluids may have weak structure in the absence of flow. Very small shear rates could cause this structure to collapse in response to shear resulting in a lowering of the viscosity of the fluid. The hypothesis of this research is that: Shear thinning in undercooled liquids decreases the viscosity, increasing the rate of nucleation and crystallization of glass forming melts. Shear in the melt can be reduced in low-g, thus enhancing undercooling and glass formation. The viscosity of a model glass (lithium di-silicate, L2S) often used for crystallization studies has been measured at very low shear rates using a dynamic mechanical thermal analyzer. Our results are consistent with increasing viscosity with a lowering of shear rates. The viscosity of L2S may vary as much as an order of magnitude depending on the shear rate in the temperature region of maximum nucleation and crystal growth. Classical equations for nucleation and crystal growth rates, are inversely related to the viscosity and viscosity to the third power respectively. An order of magnitude variation in viscosity (with shear) at a given temperature would have dramatic effects on glass crystallization Crystallization studies with the heavy metal fluoride glass ZBLAN (ZrF2-BaF2-LaF3-AlF3-NaF) to examine the effect of shear on crystallization are being initiated. Samples are to be melted and quenched under quiescent conditions at different shear rates to determine the effect

  4. Do Fluoride Ions Protect Teeth?

    ERIC Educational Resources Information Center

    Parkin, Christopher

    1998-01-01

    Begins with the procedure and results from an investigation on the effect of fluoride on the reaction between eggshell (substitute teeth) and dilute ethanoic acid. Describes an elegantly modified and improvised apparatus. (DDR)

  5. Changing of optical absorption and scattering coefficients in nonlinear-optical crystal lithium triborate before and after interaction with UV-radiation

    NASA Astrophysics Data System (ADS)

    Demkin, Artem S.; Nikitin, Dmitriy G.; Ryabushkin, Oleg A.

    2016-04-01

    In current work optical properties of LiB3O5 (LBO) crystal with ultraviolet (UV) (λ= 266 nm) induced volume macroscopic defect (track) are investigated using novel piezoelectric resonance laser calorimetry technique. Pulsed laser radiation of 10 W average power at 532 nm wavelength, is consecutively focused into spatial regions with and without optical defect. For these cases exponential fitting of crystal temperature kinetics measured during its irradiation gives different optical absorption coefficients α1 = 8.1 • 10-4 cm-1 (region with defect) and α =3.9ṡ10-4 cm-1 (non-defected region). Optical scattering coefficient is determined as the difference between optical absorption coefficients measured for opaque and transparent lateral facets of the crystal respectively. Measurements reveal that scattering coefficient of LBO in the region with defect is three times higher than the optical absorption coefficient.

  6. A new approach to prepare nanoscopic rare earth metal fluorides: the fluorolytic sol-gel synthesis of ytterbium fluoride.

    PubMed

    Schmidt, L; Dimitrov, A; Kemnitz, E

    2014-06-25

    A new approach for the preparation of approx. 5 nm sized ytterbium fluoride nanoparticles based on the fluorolytic sol-gel route is reported. DLS, TEM, IR and XRD were used to characterize the particles as well as the aging behavior of the sols. Furthermore, a new Yb(III) complex was isolated from the precursor solution and characterized by X-ray single crystal structure determination.

  7. Molten salt lithium cells

    DOEpatents

    Raistrick, Ian D.; Poris, Jaime; Huggins, Robert A.

    1983-01-01

    Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in the temperature range of about 400.degree.-500.degree. C. Such high temperature operation accelerates corrosion problems and a substantial amount of energy is lost through heat transfer. The present invention provides an electrochemical cell (10) which may be operated at temperatures between about 100.degree.-170.degree. C. Cell (10) comprises an electrolyte (16), which preferably includes lithium nitrate, and a lithium or lithium alloy electrode (12).

  8. Molten salt lithium cells

    DOEpatents

    Raistrick, I.D.; Poris, J.; Huggins, R.A.

    1980-07-18

    Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in the temperature range of about 400 to 500/sup 0/C. Such high temperature operation accelerates corrosion problems and a substantial amount of energy is lost through heat transfer. The present invention provides an electrochemical cell which may be operated at temperatures between about 100 to 170/sup 0/C. The cell is comprised of an electrolyte, which preferably includes lithium nitrate, and a lithium or lithium alloy electrode.

  9. Molten salt lithium cells

    DOEpatents

    Raistrick, Ian D.; Poris, Jaime; Huggins, Robert A.

    1982-02-09

    Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in the temperature range of about 400.degree.-500.degree. C. Such high temperature operation accelerates corrosion problems and a substantial amount of energy is lost through heat transfer. The present invention provides an electrochemical cell (10) which may be operated at temperatures between about 100.degree.-170.degree. C. Cell (10) comprises an electrolyte (16), which preferably includes lithium nitrate, and a lithium or lithium alloy electrode (12).

  10. Covalent versus ionic bonding in alkalimetal fluoride oligomers.

    PubMed

    Bickelhaupt, F M; Solà, M; Guerra, C Fonseca

    2007-01-15

    The most polar bond in chemistry is that between a fluorine and an alkalimetal atom. Inspired by our recent finding that other polar bonds (C--M and H--M) have important covalent contributions (i.e., stabilization due to bond overlap), we herein address the question if covalency is also essential in the F--M bond. Thus, we have theoretically studied the alkalimetal fluoride monomers, FM, and (distorted) cubic tetramers, (FM)4, with M=Li, Na, K, and Rb, using density functional theory at the BP86/TZ2P level. Our objective is to determine how the structure and thermochemistry (e.g., F--M bond lengths and strengths, oligomerization energies, etc.) of alkalimetal fluorides depend on the metal atom, and to understand the emerging trends in terms of quantitative Kohn-Sham molecular orbital theory. The analyses confirm the extreme polarity of the F--M bond (dipole moment, Voronoi deformation density and Hirshfeld atomic charges), and they reveal that bond overlap-derived stabilization (ca. -6, -6, and -2 kcal/mol) contributes only little to the bond strength (-136, -112, and -114 kcal/mol) and the trend therein along Li, Na, and K. According to this and other criteria, the F--M bond is not only strongly polar, but also has a truly ionic bonding mechanism. Interestingly, the polarity is reduced on tetramerization. For the lithium and sodium fluoride tetramers, the F4 tetrahedron is larger than and surrounds the M4 cluster (i.e., F--F>M--M). But in the potassium and rubidium fluoride tetramers, the F4 tetrahedron is smaller than and inside the M4 cluster (i.e., F--F

  11. Intergranular fracture of lithium fluoride-22 percent calcium fluoride hypereutectic salt at 800 K

    NASA Technical Reports Server (NTRS)

    Raj, Subramanium V.; Whittenberger, J. Daniel

    1990-01-01

    Substantial strain-hardening was noted during the initial stages of deformation in constant-velocity compression tests conducted on as-cast samples of the LiF-22 mol pct CaF2 hypereutectic salt at 800 K. The deformed specimens exhibited extensive grain-boundary cracking and cavitation, suggesting that such cracking, in conjunction with interfacial sliding, is important for cavity nucleation at grain boundaries and at the LiF-CaF2 interfaces. Cavity growth and interlinkage occur through the preferential failure of the weaker LiF phase.

  12. Holographic data storage crystals for the LDEF

    NASA Technical Reports Server (NTRS)

    Callen, W. Russell; Gaylord, Thomas K.

    1993-01-01

    Crystals of lithium niobate were passively exposed to the space environment of the Long Duration Exposure Facility (LDEF). Three of the four crystals contained volume holograms. Although the crystals suffered the surface damage characteristic of that suffered by other components on the Georgia Tech tray, the crystals remained suitable for the formation of volume holograms.

  13. Complete sets of elastic constants and photoelastic coefficients of pure and MgO-doped lithium niobate crystals at room temperature

    SciTech Connect

    Andrushchak, A. S.; Laba, H. P.; Yurkevych, O. V.; Mytsyk, B. G.; Solskii, I. M.; Kityk, A. V.; Sahraoui, B.

    2009-10-01

    This paper presents the results of ultrasonic measurements of LiNbO{sub 3} and LiNbO{sub 3}:MgO crystals. The tensors of piezoelectric coefficients, elastic stiffness constants, and elastic compliances are determined for both crystals at room temperature. Combining these data with the results of piezo-optical measurements, a complete set of photoelastic tensor coefficients is also calculated. Doping of LiNbO{sub 3} crystals by MgO does not lead to a considerable modification of their elastic and photoelastic properties. However, LiNbO{sub 3}:MgO is characterized by a considerably higher resistance with respect to powerful light radiation, making it promising for future application in acousto-optic devices that deal with superpowerful laser radiation. Presented here are the complete tensor sets of elastic constants and photoelastic coefficients of LiNbO{sub 3} and LiNbO{sub 3}:MgO crystals that may be used for a geometry optimization of acousto-optical interaction providing the best diffraction efficiency of acousto-optical cells made of these materials.

  14. A Novel Fluoride Route for the Synthesis of Aluminosilicate Nanotubes

    PubMed Central

    Chemmi, Atika; Brendlé, Jocelyne; Marichal, Claire; Lebeau, Bénédicte

    2013-01-01

    In this work we present a novel method for synthesis of aluminosilicate nanotubes: the fluoride route. F-containing imogolite (F-IMO) exhibits an improved crystallization rate and improved yield. The structure of F-IMO was investigated and compared with F-free imogolite (IMO) by means of X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR) confirming imogolite structure. Solid state nuclear magnetic resonance (NMR) analyses show an increased crystallization rate for F-IMO and confirm the incorporation of fluorine ion in the structure. PMID:28348325

  15. Polymorphism Control of Poly(vinylidene fluoride)

    NASA Astrophysics Data System (ADS)

    Zheng, Jianfen; He, Aihua; Li, Junxing; Han, Charles C.

    2008-03-01

    Poly(vinylidene fluoride) (PVDF) is well-known for its polymorphism, and can exhibit five different polymorphs depending on its processing conditions. The α-phase is the most common and stable polymorph and the β-phase is the most important one due to its piezoelectric and pyroelectric properties. Polymorphism control of PVDF has been realized through electrospinning. PVDF fibrous membranes with fiber diameter in the range of 100 nm to several micrometers were produced by electrospinning and the crystal phase of electrospun PVDF fibers can be adjusted at the same time. Through the control of electrospinning parameters such as the solvent and electrospinning temperature, PVDF fibrous membranes containing mainly α- or β- or γ-phase could be fabricated successfully.

  16. Sub-2 nm Thick Fluoroalkylsilane Self-Assembled Monolayer-Coated High Voltage Spinel Crystals as Promising Cathode Materials for Lithium Ion Batteries

    PubMed Central

    Zettsu, Nobuyuki; Kida, Satoru; Uchida, Shuhei; Teshima, Katsuya

    2016-01-01

    We demonstrate herein that an ultra-thin fluoroalkylsilane self-assembled monolayer coating can be used as a modifying agent at LiNi0.5Mn1.5O4−δcathode/electrolyte interfaces in 5V-class lithium-ion batteries. Bare LiNi0.5Mn1.5O4−δ cathode showed substantial capacity fading, with capacity dropping to 79% of the original capacity after 100 cycles at a rate of 1C, which was entirely due to dissolution of Mn3+ from the spinel lattice via oxidative decomposition of the organic electrolyte. Capacity retention was improved to 97% on coating ultra-thin FAS17-SAM onto the LiNi0.5Mn1.5O4 cathode surface. Such surface protection with highly ordered fluoroalkyl chains insulated the cathode from direct contact with the organic electrolyte and led to increased tolerance to HF. PMID:27553901

  17. Chronic fluoride toxicity: dental fluorosis.

    PubMed

    Denbesten, Pamela; Li, Wu

    2011-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2-3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface. With more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the dose-related decrease in cycles of ameloblast modulation from ruffle-ended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As further

  18. Acute toxicity of ingested fluoride.

    PubMed

    Whitford, Gary Milton

    2011-01-01

    This chapter discusses the characteristics and treatment of acute fluoride toxicity as well as the most common sources of overexposure, the doses that cause acute toxicity, and factors that can influence the clinical outcome. Cases of serious systemic toxicity and fatalities due to acute exposures are now rare, but overexposures causing toxic signs and symptoms are not. The clinical course of systemic toxicity from ingested fluoride begins with gastric signs and symptoms, and can develop with alarming rapidity. Treatment involves minimizing absorption by administering a solution containing calcium, monitoring and managing plasma calcium and potassium concentrations, acid-base status, and supporting vital functions. Approximately 30,000 calls to US poison control centers concerning acute exposures in children are made each year, most of which involve temporary gastrointestinal effects, but others require medical treatment. The most common sources of acute overexposures today are dental products - particularly dentifrices because of their relatively high fluoride concentrations, pleasant flavors, and their presence in non-secure locations in most homes. For example, ingestion of only 1.8 ounces of a standard fluoridated dentifrice (900-1,100 mg/kg) by a 10-kg child delivers enough fluoride to reach the 'probably toxic dose' (5 mg/kg body weight). Factors that may influence the clinical course of an overexposure include the chemical compound (e.g. NaF, MFP, etc.), the age and acid-base status of the individual, and the elapsed time between exposure and the initiation of treatment. While fluoride has well-established beneficial dental effects and cases of serious toxicity are now rare, the potential for toxicity requires that fluoride-containing materials be handled and stored with the respect they deserve.

  19. Chronic Fluoride Toxicity: Dental Fluorosis

    PubMed Central

    DenBesten, Pamela; Li, Wu

    2012-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2–3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface; with more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix/mineral interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the doserelated decrease in cycles of ameloblast modulation from ruffleended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As

  20. Lithium Battery Diaper Ulceration.

    PubMed

    Maridet, Claire; Taïeb, Alain

    2016-01-01

    We report a case of lithium battery diaper ulceration in a 16-month-old girl. Gastrointestinal and ear, nose, and throat lesions after lithium battery ingestion have been reported, but skin involvement has not been reported to our knowledge.

  1. Properties of heterogeneous apatites containing magnesium, fluoride, and carbonate.

    PubMed

    Okazaki, M; LeGeros, R Z

    1996-11-01

    Biological apatites present in the mineral phases of normal and pathological calcifications contain magnesium, Mg, and carbonate, CO3. As a consequence of fluctuations in the composition of the micro-environment, these apatites may sometimes form by heterogeneous precipitation. The purpose of this study was to investigate the properties of (Mg, CO3)-apatites formed heterogeneously in the presence of fluoride, F. Two types of fluoridated (Mg, CO3)-apatites formed from solutions with low and high levels of Mg were prepared at 80 degrees C, pH 7.4. We prepared FMgCO3-MgCO3AP (Type 1) by adding the F-containing solution to those containing calcium, Mg, and phosphate ions during the first half of the precipitation period. We prepared MgCO3-FMgCO3Ap (Type 2) by adding the F-containing solution during the final half of the period. The apatites were analyzed by x-ray diffraction (XRD), infrared absorption spectroscopy, and scanning electron microscopy (SEM). SEM and XRD analyses showed evidence of mixed crystals in the heterogeneous apatites. The presence of Mg inhibits, while F promotes, apatite crystal growth. In addition, Mg incorporation increased with increasing fluoride concentration. The extent of dissolution in acid buffer of both types of heterogeneous apatites increased with Mg: Type 1 > Type 2. These results suggest that the crystal and dissolution properties of heterogeneous fluoridated (Mg, CO3)-apatites are greatly affected by the mode of F incorporation and Mg concentrations in the environment.

  2. Hydrothermal scandium fluoride chemistry: syntheses and crystal structures of [C 2N 2H 10][ScF 5], [NH 4] 2[Sc 3F 11] and [H 3O][C 6N 2H 16][ScF 6]ṡH 2O

    NASA Astrophysics Data System (ADS)

    Stephens, Nicholas F.; Lightfoot, Philip

    2006-02-01

    The hydrothermal syntheses and crystal structures of three new scandium fluorides are reported. [enH 2][ScF 5] 1 exhibits continuous chains of vertex linked ScF 6 octahedra, which adopt two differing conformations (eclipsed and staggered). [NH 4] 2[Sc 3F 11] 2, displays a three-dimensional framework structure composed of edge and corner-shared ScF 7 pentagonal bipyramids interlinked via octahedral scandium centres. This structure encloses 'butterfly'-shaped channels, and may be regarded as an 'expanded' version of the KSc 2F 7 structure, derived by insertion of the additional octahedral unit between neighbouring pentagonal bipyramidal chains. [H 3O][C 6N 2H 16][ScF 6]ṡH 2O 3 is composed of isolated ScF 6 octahedra hydrogen-bonded to trans-1,4-diaminocyclohexane cations and water molecules/hydronium cations. Crystal data for 1: tetragonal, space group P4/ncc, a=13.035(2) Å, c=8.142(2) Å; for 2: orthorhombic, space group Cmmm, a=18.501(12) Å, b=6.613(5) Å, c=4.025(3) Å; for 3: monoclinic, space group P2 1/n, a=9.543(2) Å, b=6.704(1) Å, c=9.873(2) Å, β=90.349(5)°.

  3. EFFECT OF LASER LIGHT ON MATTER. LASER PLASMAS: Laser damage resistance of a lithium niobate-tantalate bicrystal system

    NASA Astrophysics Data System (ADS)

    Skvortsov, L. A.; Stepantsov, E. S.

    1993-11-01

    The laser damage resistance of a bicrystal system prepared by solid-phase diffusive joining of specially prepared crystals of lithium niobate and lithium tantalate has been studied. This has been the first such study. The damage resistance of the interface is at least twice that of the lithium niobate surface. The damage resistance of the bicrystal is determined by the damage resistance of the lithium tantalate surface and is greater than 600 MW/cm2.

  4. Lithium Batteries: A Practical Application of Chemical Principles

    NASA Astrophysics Data System (ADS)

    Treptow, Richard S.

    2003-09-01

    In recent years batteries have emerged in the marketplace that take advantage of the unique properties of lithium. Lithium metal is an attractive choice to serve as a battery anode because it is easily oxidized and it produces an exceptionally high amount of electrical charge per unit-weight. The electrolytes used in lithium batteries contain lithium salts dissolved in polar organic solvents. A variety of substances can serve as the battery cathode. They include inorganic solids, liquids, and dissolved gas. The cell potentials of lithium-metal batteries can be calculated from thermodynamic principles. These open-circuit voltages can be compared to the operating voltages of batteries delivering a current. Some lithium batteries employ intercalation compounds as their cathodes. These solids have layered or tunneled crystal structures into which lithium ions insert during the reduction process. When an intercalation cathode is paired with a lithiated-graphite anode, the resulting battery has the advantage of being rechargeable. It is known as a lithium-ion battery because no lithium metal is present.

  5. Lithium Cell Reactions.

    DTIC Science & Technology

    1985-02-01

    Page 1. INVESTIGATION OF CHEMICAL, ELECTROCHEMICAL AND PARASITIC REACTIONS IN LITHIUM - THIONYL CHLORIDE CELLS ....... ................. 1 1.1 INTRODUCTION...OF LITHIUM - THIONYL CHLORIDE CELLS. ................ 56 1.4.1 Carbon Limited Overdischarge...............56 1.4.1.1 Background... LITHIUM THIONYL - CHLORIDE CELLS. .. ............ ...... 101 1.5.1 Background. ....... ............ .... 101 1.5.2 Microphotography

  6. Lithium Cell Reactions.

    DTIC Science & Technology

    1983-12-01

    SUPPLEMENTARY NOTES It. KEY WORDS (Continue on reverse .,ide if necessary and Identify by block number) Batteries Thionyl Chloride Batteries Lithium ...Batteries Lithium Cells Primary Batteries Thionyl Chloride Cells Non Rechargeable Batteries Electrochemical Reactions 20. ABSTRACT (Continue on reverse...INVESTIGATION OF CHEMICAL, ELECTROCHEMICAL AND PARASITIC REACTIONS IN LITHIUM - THIONYL CHLORIDE CELLS .......................................... 1 1.0 IN TRO D UC

  7. [Natural fluorides. The distinction between technically produced and naturally occurring fluorides in caries prophylaxis].

    PubMed

    Newesely, H

    1977-06-01

    In the controversial discussion of the bio-availability of fluoride in caries prophylaxis by fluoridation, fluorides coming from the geochemical circulation to the biochemical circulation are sometimes differentiated from synthetic fluorides introduced into fluoride medication. The question as to whether such a differentiation is essential can be answered from the physical-chemical point of view. This requires a wide field of scientific research starting with geochemistry and the knowledge of fluoride deposits, sedimentology, hydrology, technology of inorganic and organic fluorine compounds, thermodynamics of dissolved fluorides, up to biocrystallography and biochemistry of fluorine.

  8. Ferroelectric domain engineering and micro-structuring of lithium niobate

    NASA Astrophysics Data System (ADS)

    Mailis, Sakellaris

    2010-11-01

    This paper discusses a number of recently developed all optical and optically assisted methods for ferroelectric domain engineering in lithium niobate and their impact on the micro-structuring of this optical ferroelectric crystal. Optical radiation is used to change the response of lithium niobate crystals to externally applied electric field encouraging or inhibiting ferroelectric domain inversion in a simultaneous or latent manner. Optically assisted poling processes have the advantage of producing ferroelectric domains with arbitrary shapes free from crystal symmetry restrictions which is very important for fabricating surface micro/nano-structures in this material.

  9. High-fluoride groundwater.

    PubMed

    Rao, N Subba

    2011-05-01

    Fluoride (F(-)) is essential for normal bone growth, but its higher concentration in the drinking water poses great health problems and fluorosis is common in many parts of India. The present paper deals with the aim of establishment of facts of the chemical characteristics responsible for the higher concentration of F(-) in the groundwater, after understanding the chemical behavior of F(-) in relation to pH, total alkalinity (TA), total hardness (TH), carbonate hardness (CH), non-carbonate hardness (NCH), and excess alkalinity (EA) in the groundwater observed from the known areas of endemic fluorosis zones of Andhra Pradesh that have abundant sources of F(-)-bearing minerals of the Precambrians. The chemical data of the groundwater shows that the pH increases with increase F(-); the concentration of TH is more than the concentration of TA at low F(-) groundwater, the resulting water is represented by NCH; the TH has less concentration compared to TA at high F(-) groundwater, causing the water that is characterized by EA; and the water of both low and high concentrations of F(-) has CH. As a result, the F(-) has a positive relation with pH and TA, and a negative relation with TH. The operating mechanism derived from these observations is that the F(-) is released from the source into the groundwater by geochemical reactions and that the groundwater in its flowpath is subjected to evapotranspiration due to the influence of dry climate, which accelerates a precipitation of CaCO(3) and a reduction of TH, and thereby a dissolution of F(-). Furthermore, the EA in the water activates the alkalinity in the areas of alkaline soils, leading to enrichment of F(-). Therefore, the alkaline condition, with high pH and EA, and low TH, is a more conducive environment for the higher concentration of F(-) in the groundwater.

  10. Microcratering in Polyvinylidene Fluoride

    NASA Astrophysics Data System (ADS)

    Shu, Anthony John

    Dust is defined as macroparticles as small as a few molecules up to several micrometers in diameter. In the context of space exploration, it was originally seen only as a technical obstacle to applications; dust can damage instrument surfaces, coat mating surfaces preventing proper seals, and impair or obstruct measurements. Because of the ubiquity of dust in the solar system and its role in the origin of planets and other bodies, the study of dust and related phenomena has evolved to a scientific subdiscipline which can provide us insight into the origins and evolution of our solar system. In order to facilitate this, a hypervelocity dust accelerator has been built at the University of Colorado at Boulder and is being used to probe impact phenomena, dust mitigation techniques, dust detection techniques, and more. One such dust detector is a Polyvinylidene Fluoride (PVDF) dust detector. The PVDF dust detector is very lightweight and consumes little power. Due to these properties, PVDF detectors can potentially be used on any spacecraft to gain information on the local dust environment. It is not fully understood how this PVDF dust detector signal is generated, so at present can only be used as a dust counter. In this thesis I discuss the importance of the study of dust phenomena, describe the accelerator experiment, and describe a study conducted to determine the underlying physical principles of PVDF dust detectors. This included measuring crater size scaling laws, measuring the detailed shape of craters, and applying this data to simulations of the signals being generated by PVDF detectors.

  11. Lithium use in batteries

    USGS Publications Warehouse

    Goonan, Thomas G.

    2012-01-01

    Lithium has a number of uses but one of the most valuable is as a component of high energy-density rechargeable lithium-ion batteries. Because of concerns over carbon dioxide footprint and increasing hydrocarbon fuel cost (reduced supply), lithium may become even more important in large batteries for powering all-electric and hybrid vehicles. It would take 1.4 to 3.0 kilograms of lithium equivalent (7.5 to 16.0 kilograms of lithium carbonate) to support a 40-mile trip in an electric vehicle before requiring recharge. This could create a large demand for lithium. Estimates of future lithium demand vary, based on numerous variables. Some of those variables include the potential for recycling, widespread public acceptance of electric vehicles, or the possibility of incentives for converting to lithium-ion-powered engines. Increased electric usage could cause electricity prices to increase. Because of reduced demand, hydrocarbon fuel prices would likely decrease, making hydrocarbon fuel more desirable. In 2009, 13 percent of worldwide lithium reserves, expressed in terms of contained lithium, were reported to be within hard rock mineral deposits, and 87 percent, within brine deposits. Most of the lithium recovered from brine came from Chile, with smaller amounts from China, Argentina, and the United States. Chile also has lithium mineral reserves, as does Australia. Another source of lithium is from recycled batteries. When lithium-ion batteries begin to power vehicles, it is expected that battery recycling rates will increase because vehicle battery recycling systems can be used to produce new lithium-ion batteries.

  12. Frequency doubling crystals

    DOEpatents

    Wang, Francis; Velsko, Stephan P.

    1989-01-01

    A systematic approach to the production of frequency conversion crystals is described in which a chiral molecule has attached to it a "harmonic generating unit" which contributes to the noncentrosymmetry of the molecule. Certain preferred embodiments of such harmonic generating units include carboxylate, guanadyly and imidazolyl units. Certain preferred crystals include L-arginine fluoride, deuterated L-arginine fluoride, L-arginine chloride monohydrate, L-arginine acetate, dithallium tartrate, ammonium N-acetyl valine, N-acetyl tyrosine and N-acetyl hydroxyproline. Chemical modifications of the chiral molecule, such as deuteration, halogenation and controlled counterion substitution are available to adapt the dispersive properties of a crystal in a particular wavelength region.

  13. Fluoride Glass Fibres For Telecommunications

    NASA Astrophysics Data System (ADS)

    Maze, Gwenael; Cardin, Vincent; Poulain, Marcel

    1983-09-01

    Zirconium fluoride glasses are the best known and the most stable beryllium-free glasses. They offer numerous potential uses for I.R.-transmitting fibres and ultra-long repeaterless optical wave-guides. Various problems arise in the manufacturing of fluoride glass fibres, essentially because of the steep viscosity profile and the devitrification phenomena. This paper discusses the processes for manufacturing step-index preforms and for drawing fibres. Optical quality preforms have been obtained and fibres have been drawn over more than 1 km. A spectral loss measurement system has been constructed using fluoride glass optical components. Several curves showing the optical attenuation versus wavelength are presented and discussed. These fibres are now available for optical transmission in infra-red systems.

  14. Reciprocated suppression of polymer crystallization toward improved solid polymer electrolytes: Higher ion conductivity and tunable mechanical properties

    SciTech Connect

    Bi, Sheng; Sun, Che-Nan; Zawodzinski, Thomas A.; Ren, Fei; Keum, Jong Kahk; Ahn, Suk-Kyun; Li, Dawen; Chen, Jihua

    2015-08-06

    Solid polymer electrolytes based on lithium bis(trifluoromethanesulfonyl) imide and polymer matrix were extensively studied in the past due to their excellent potential in a broad range of energy related applications. Poly(vinylidene fluoride) (PVDF) and polyethylene oxide (PEO) are among the most examined polymer candidates as solid polymer electrolyte matrix. In this paper, we study the effect of reciprocated suppression of polymer crystallization in PVDF/PEO binary matrix on ion transport and mechanical properties of the resultant solid polymer electrolytes. With electron and X-ray diffractions as well as energy filtered transmission electron microscopy, we identify and examine the appropriate blending composition that is responsible for the diminishment of both PVDF and PEO crystallites. Laslty, a three-fold conductivity enhancement is achieved along with a highly tunable elastic modulus ranging from 20 to 200 MPa, which is expected to contribute toward future designs of solid polymer electrolytes with high room-temperature ion conductivities and mechanical flexibility.

  15. Anhydrous hydrogen fluoride electrolyte battery. [Patent application

    DOEpatents

    Not Available

    1972-06-26

    It is an object of the invention to provide a primary cell or battery using ammonium fluoride--anhydrous hydrogen fluoride electrolyte having improved current and power production capabilities at low temperatures. It is operable at temperatures substantially above the boiling point of hydrogen fluoride. (GRA)

  16. A Manual for Rural School Fluoridation.

    ERIC Educational Resources Information Center

    Sprouse, Larman W.; Brooks, John

    The product of a 1972 Dental Health Branch contract with the U.S. Public Health Service, this manual is designed to aid in the development of school fluoridation programs and presents: background information on general concepts relating to the action of fluoride on teeth; discussions dealing with community and school fluoridation studies; and the…

  17. The Effect of Fluoride in Osteoporosis.

    ERIC Educational Resources Information Center

    Hedlund, L. R.; Gallagher, J. C.

    1987-01-01

    This article discusses the effect of fluoride on bone tissue and the possible role of fluoride in the treatment of osteoporosis. At present, fluoride treatment should be restricted to clinical trials until its risks and benefits have been further evaluated. (Author/MT)

  18. METHOD OF PREPARING METAL FLUORIDES

    DOEpatents

    Katz, J.J.; Sheft, I.

    1959-08-11

    A method is presented for preparing the halides of elements which are relatively non-reactive with halogenating agents. The method involves reacting a mixture of an oxygen containing salt of a difficulty halogenated metal with an oxygen containing salt of an easily halogenated metal with a halogenating agent. Accordingly plutonium tetrafluoride is produced by reacting a mixture of plutonium dioxide and uranium octaoxide with bromine trifluoride. The reaction proceeds smoothly at moderate temperatures and the resulting plutonium trifluoride may be readily separated from many impurities which form volatile fluorides by volatilizing these volatile fluorides from the reaction chamber.

  19. Crystal structure and characterization of a novel layered copper-lithium phosphonate with antiferromagnetic intrachain Cu(II)···Cu(II) interactions

    NASA Astrophysics Data System (ADS)

    Abdelbaky, Mohammed S. M.; Amghouz, Zakariae; Blanco, David Martínez; García-Granda, Santiago; García, José R.

    2017-04-01

    Novel metal phosphonate [CuLi(PPA)] [H3PPA=3-phosphonopropionic acid] was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. It crystallizes in the space group C2/c, with cell parameters a=21.617(2) Å, b=4.9269(2) Å, c=14.342(1) Å, β=132.3(2)°, and Z=8. Its framework is built up from a main trimer, acting as a secondary building unit (SBU), which is formed by vertex-shared between two {LiO4} and one {Cu(1)O4} polyhedra. These units repeat along b-axis forming infinite inorganic chains, these chains are in turn cross-linked by corner sharing with {Cu(2)O4} polyhedra to produce inorganic layers lying in the bc-plane. The neighboring layers are connected through the PPA ligand, leading to a 3D pillared-layered structure. The topological analysis reveals that the compound exhibits 3,4,10-c net. Finally, magnetic susceptibility measurement of this compound over the temperature range of 2-300 K reveals the occurrence of weak antiferromagnetic intrachain interactions.

  20. Single crystal micromechanical resonator and fabrication methods thereof

    DOEpatents

    Olsson, Roy H.; Friedmann, Thomas A.; Homeijer, Sara Jensen; Wiwi, Michael; Hattar, Khalid Mikhiel; Clark, Blythe; Bauer, Todd; Van Deusen, Stuart B.

    2016-12-20

    The present invention relates to a single crystal micromechanical resonator. In particular, the resonator includes a lithium niobate or lithium tantalate suspended plate. Also provided are improved microfabrication methods of making resonators, which does not rely on complicated wafer bonding, layer fracturing, and mechanical polishing steps. Rather, the methods allow the resonator and its components to be formed from a single crystal.

  1. The synergetic effect of lithium polysulfide and lithium nitrate to prevent lithium dendrite growth

    NASA Astrophysics Data System (ADS)

    Li, Weiyang; Yao, Hongbin; Yan, Kai; Zheng, Guangyuan; Liang, Zheng; Chiang, Yet-Ming; Cui, Yi

    2015-06-01

    Lithium metal has shown great promise as an anode material for high-energy storage systems, owing to its high theoretical specific capacity and low negative electrochemical potential. Unfortunately, uncontrolled dendritic and mossy lithium growth, as well as electrolyte decomposition inherent in lithium metal-based batteries, cause safety issues and low Coulombic efficiency. Here we demonstrate that the growth of lithium dendrites can be suppressed by exploiting the reaction between lithium and lithium polysulfide, which has long been considered as a critical flaw in lithium-sulfur batteries. We show that a stable and uniform solid electrolyte interphase layer is formed due to a synergetic effect of both lithium polysulfide and lithium nitrate as additives in ether-based electrolyte, preventing dendrite growth and minimizing electrolyte decomposition. Our findings allow for re-evaluation of the reactions regarding lithium polysulfide, lithium nitrate and lithium metal, and provide insights into solving the problems associated with lithium metal anodes.

  2. Unusual hydrogen bonding in L-cysteine hydrogen fluoride.

    PubMed

    Minkov, V S; Ghazaryan, V V; Boldyreva, E V; Petrosyan, A M

    2015-08-01

    L-Cysteine hydrogen fluoride, or bis(L-cysteinium) difluoride-L-cysteine-hydrogen fluoride (1/1/1), 2C3H8NO2S(+)·2F(-)·C3H7NO2S·HF or L-Cys(+)(L-Cys···L-Cys(+))F(-)(F(-)...H-F), provides the first example of a structure with cations of the 'triglycine sulfate' type, i.e. A(+)(A···A(+)) (where A and A(+) are the zwitterionic and cationic states of an amino acid, respectively), without a doubly charged counter-ion. The salt crystallizes in the monoclinic system with the space group P2(1). The dimeric (L-Cys···L-Cys(+)) cation and the dimeric (F(-)···H-F) anion are formed via strong O-H···O or F-H···F hydrogen bonds, respectively, with very short O···O [2.4438 (19) Å] and F···F distances [2.2676 (17) Å]. The F···F distance is significantly shorter than in solid hydrogen fluoride. Additionally, there is another very short hydrogen bond, of O-H···F type, formed by a L-cysteinium cation and a fluoride ion. The corresponding O···F distance of 2.3412 (19) Å seems to be the shortest among O-H···F and F-H···O hydrogen bonds known to date. The single-crystal X-ray diffraction study was complemented by IR spectroscopy. Of special interest was the spectral region of vibrations related to the above-mentioned hydrogen bonds.

  3. Ternary metal fluorides as high-energy cathodes with low cycling hysteresis

    PubMed Central

    Wang, Feng; Kim, Sung-Wook; Seo, Dong-Hwa; Kang, Kisuk; Wang, Liping; Su, Dong; Vajo, John J.; Wang, John; Graetz, Jason

    2015-01-01

    Transition metal fluorides are an appealing alternative to conventional intercalation compounds for use as cathodes in next-generation lithium batteries due to their extremely high capacity (3–4 times greater than the current state-of-the-art). However, issues related to reversibility, energy efficiency and kinetics prevent their practical application. Here we report on the synthesis, structural and electrochemical properties of ternary metal fluorides (M1yM21-yFx: M1, M2=Fe, Cu), which may overcome these issues. By substituting Cu into the Fe lattice, forming the solid–solution CuyFe1-yF2, reversible Cu and Fe redox reactions are achieved with surprisingly small hysteresis (<150 mV). This finding indicates that cation substitution may provide a new avenue for tailoring key electrochemical properties of conversion electrodes. Although the reversible capacity of Cu conversion fades rapidly, likely due to Cu+ dissolution, the low hysteresis and high energy suggest that a Cu-based fluoride cathode remains an intriguing candidate for rechargeable lithium batteries. PMID:25808876

  4. Ternary metal fluorides as high-energy cathodes with low cycling hysteresis

    DOE PAGES

    Wang, Feng; Kim, Sung -Wook; Seo, Dong -Hwa; ...

    2015-03-26

    In this study, transition metal fluorides are an appealing alternative to conventional intercalation compounds for use as cathodes in next-generation lithium batteries due to their extremely high capacity (3–4 times greater than the current state-of-the-art). However, issues related to reversibility, energy efficiency and kinetics prevent their practical application. Here we report on the synthesis, structural and electrochemical properties of ternary metal fluorides (M1yM21-yFx: M1, M2 = Fe, Cu), which may overcome these issues. By substituting Cu into the Fe lattice, forming the solid–solution CuyFe1-yF2, reversible Cu and Fe redox reactions are achieved with surprisingly small hysteresis (<150 mV). This findingmore » indicates that cation substitution may provide a new avenue for tailoring key electrochemical properties of conversion electrodes. In conclusion, although the reversible capacity of Cu conversion fades rapidly, likely due to Cu+ dissolution, the low hysteresis and high energy suggest that a Cu-based fluoride cathode remains an intriguing candidate for rechargeable lithium batteries.« less

  5. Ternary metal fluorides as high-energy cathodes with low cycling hysteresis

    SciTech Connect

    Wang, Feng; Kim, Sung -Wook; Seo, Dong -Hwa; Kang, Kisuk; Wang, Liping; Su, Dong; Vajo, John J.; Wang, John; Gratez, Jason

    2015-03-26

    In this study, transition metal fluorides are an appealing alternative to conventional intercalation compounds for use as cathodes in next-generation lithium batteries due to their extremely high capacity (3–4 times greater than the current state-of-the-art). However, issues related to reversibility, energy efficiency and kinetics prevent their practical application. Here we report on the synthesis, structural and electrochemical properties of ternary metal fluorides (M1yM21-yFx: M1, M2 = Fe, Cu), which may overcome these issues. By substituting Cu into the Fe lattice, forming the solid–solution CuyFe1-yF2, reversible Cu and Fe redox reactions are achieved with surprisingly small hysteresis (<150 mV). This finding indicates that cation substitution may provide a new avenue for tailoring key electrochemical properties of conversion electrodes. In conclusion, although the reversible capacity of Cu conversion fades rapidly, likely due to Cu+ dissolution, the low hysteresis and high energy suggest that a Cu-based fluoride cathode remains an intriguing candidate for rechargeable lithium batteries.

  6. Total fluoride intake and excretion in children up to 4 years of age living in fluoridated and non-fluoridated areas.

    PubMed

    Zohoori, F V; Buzalaf, M A R; Cardoso, C A B; Olympio, K P K; Levy, F M; Grizzo, L T; Mangueira, D F B; Sampaio, F C; Maguire, A

    2013-10-01

    Fractional fluoride retention is important during the early years of life when considering the risk of development of dental fluorosis. This study aimed to measure fractional fluoride retention in young children. The objectives were to investigate the relationships between fractional fluoride retention and total daily fluoride intake, age, and body mass index (BMI). Twenty-nine healthy children, up to 4 yr of age, participated; 14 lived in a fluoridated area (0.64 μg ml(-1) of fluoride in drinking water) and 15 lived in a non-fluoridated area (0.04 μg ml(-1) of fluoride in drinking water). The total daily fluoride intake of each child was calculated from the daily dietary fluoride intake and toothpaste ingestion (if fluoride toothpaste was used). Total daily fluoride excretion was measured by collecting voided urine and faeces over a 24-h period, and fractional fluoride retention was calculated by dividing the amount of fluoride retained in the body (total daily fluoride intake minus total daily fluoride excretion) by the total daily fluoride intake. Nine children were excluded from data analysis because of suspected invalid samples. Mean (range) fractional fluoride retention for the remaining 20 children was 0.61 (0.06-0.98). There were no statistically significant correlations between fractional fluoride retention and either age or BMI. However, fractional fluoride retention was correlated with total daily fluoride intake: fractional fluoride retention = 1 - exp (-C × total daily fluoride intake), where C = 28.75 (95% CI = 19.75-37.75). The wide variation in fluoride retention in young children could have important implications when recommendations for fluoride use are being considered.

  7. PVDF-HFP/ether-modified polysiloxane membranes obtained via airbrush spraying as active separators for application in lithium ion batteries.

    PubMed

    Seidel, S M; Jeschke, S; Vettikuzha, P; Wiemhöfer, H-D

    2015-08-04

    Improved hybrid polymer electrolyte membranes are introduced based on ether-modified polysiloxanes and poly(vinylidene fluoride-co-hexafluoropropylene) yielding a safe separator membrane, which is able to be sprayed directly onto lithium ion battery active materials, with an active role for enhanced ion transport.

  8. Calcium fluoride formation on sound enamel using fluoride solutions with and without lactate.

    PubMed

    Harding, A M; Zero, D T; Featherstone, J D; McCormack, S M; Shields, C P; Proskin, H M

    1994-01-01

    The formation of calcium (Ca) fluoride (CaF2) on bovine enamel blocks during clinically relevant treatment times using neutral fluoride (F) solutions (0.26 mol/l F) with and without 0.1 mol/l lactate was investigated. Uncoated and pellicle-coated blocks were evaluated for alkali-soluble (1 mol/l KOH, three consecutive 24-hour treatments) Ca, PO4, and F after treatment by the F solutions for 0, 5, 15, 30, and 60 min. There was an overall time-related increase in F recovery, while Ca tended to remain at baseline levels. Less F was recovered from the pellicle-coated blocks. The addition of lactate to the F treatment solution did not result in an overall increase in alkali-soluble F recovery, but did result in the formation of cuboidal shaped crystals which closely approached the morphology of pure CaF2. A 1:2 stoichiometric ratio Ca:2F (mol:mol) was not established based on chemical analyses. The ultrastructural and elemental composition of surface deposits on the samples, as determined using scanning electron microscopy, X-ray diffraction, and energy-dispersive spectroscopy, established the presence of CaF2 after 24-hour F treatments; however, it was not possible to directly demonstrate the formation of CaF2 after clinically relevant treatment times.

  9. The role of fluoride in erosion therapy.

    PubMed

    Huysmans, Marie-Charlotte; Young, Alix; Ganss, Carolina

    2014-01-01

    The role of fluoride in erosion therapy has long been questioned. However, recent research has yielded positive results. In this chapter, an overview of the literature is provided regarding the application of fluorides in the prevention and treatment of erosion and erosive wear. The results are presented and discussed for different fluoride sources such as monovalent and polyvalent fluorides, and for different vehicles such as toothpastes, solutions and rinses, as well as varnishes and gels. It is concluded that fluoride applications are very likely to be of use in the preventive treatment of erosive wear. Most promising are high-concentration, acidic formulations and the polyvalent fluoride sources, with the best evidence available for stannous fluoride. However, the evidence base for clinical effectiveness is still small.

  10. Special Report: Fluoridation of Water.

    ERIC Educational Resources Information Center

    Hileman, Bette

    1988-01-01

    Reviews the controversy regarding water fluoridation in the United States during the last 50 years. Discusses the current status; benefits; and health risks including skeletal fluorosis, kidney disease, hypersensitivity, mutagenic effects, birth defects, and cancer. Presents statistics and anecdotal accounts. (CW)

  11. Electron Collisions with Hydrogen Fluoride

    NASA Astrophysics Data System (ADS)

    Itikawa, Yukikazu

    2017-03-01

    Cross section data are reviewed for electron collisions with hydrogen fluoride. Collision processes considered are total scattering, elastic scattering, excitations of rotational, vibrational, and electronic states, ionization, and dissociative electron attachment. After a survey of the literature, recommended values of the cross sections are determined, as far as possible.

  12. Method of recycling lithium borate to lithium borohydride through diborane

    DOEpatents

    Filby, Evan E.

    1976-01-01

    This invention provides a method for the recycling of lithium borate to lithium borohydride which can be reacted with water to generate hydrogen for utilization as a fuel. The lithium borate by-product of the hydrogen generation reaction is reacted with hydrogen chloride and water to produce boric acid and lithium chloride. The boric acid and lithium chloride are converted to lithium borohydride through a diborane intermediate to complete the recycle scheme.

  13. Fissure seal or fluoride varnish?

    PubMed

    Deery, Christopher

    2016-09-01

    Data sourcesCochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, the US National Institutes of Health Trials Register and the World Health Organization (WHO) Clinical Trials Registry PlatformStudy selectionRandomised controlled trials (RCTs) with at least 12 months follow-up, in which fissure sealants, or fissure sealants together with fluoride varnishes, were compared with fluoride varnishes alone for preventing caries in occlusal surfaces of permanent teeth of children and adolescents.Data extraction and synthesisTwo reviewers independently screened search results, extracted data and assessed risk of bias of included studies. Studies were grouped and analysed on the basis of sealant material type (resin-based sealant and glass ionomer-based sealant, glass ionomer and resin-modified glass ionomer) and different follow-up periods. Odds ratio were calculated for caries or no caries on occlusal surfaces of permanent molar teeth. Mean differences were calculated for continuous outcomes and data. Evidence quality was assessed using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) methods.ResultsEight RCTs involving a total of 1747 children aged five to ten years of age were included. Three trials compared resin-based fissure sealant versus fluoride varnish. Results from two studies (358 children) after two years were combined. Sealants prevented more caries, pooled odds ratio (OR) = 0.69 (95%CI; 0.50 to 0.94). One trial with follow-up at four and nine years found that the caries-preventive benefit for sealants was maintained, with 26% of sealed teeth and 55.8% of varnished teeth having developed caries at nine years. Evidence for glass-ionomer sealants was of low quality. One split-mouth trial analysing 92 children at two-year follow-up found a significant difference in favour of resin-based fissure sealant together with fluoride varnish compared with fluoride varnish only (OR

  14. Fluoride in groundwater: toxicological exposure and remedies.

    PubMed

    Jha, S K; Singh, R K; Damodaran, T; Mishra, V K; Sharma, D K; Rai, Deepak

    2013-01-01

    Fluoride is a chemical element that is found most frequently in groundwater and has become one of the most important toxicological environmental hazards globally. The occurrence of fluoride in groundwater is due to weathering and leaching of fluoride-bearing minerals from rocks and sediments. Fluoride when ingested in small quantities (<0.5 mg/L) is beneficial in promoting dental health by reducing dental caries, whereas higher concentrations (>1.5 mg/L) may cause fluorosis. It is estimated that about 200 million people, from among 25 nations the world over, may suffer from fluorosis and the causes have been ascribed to fluoride contamination in groundwater including India. High fluoride occurrence in groundwaters is expected from sodium bicarbonate-type water, which is calcium deficient. The alkalinity of water also helps in mobilizing fluoride from fluorite (CaF2). Fluoride exposure in humans is related to (1) fluoride concentration in drinking water, (2) duration of consumption, and (3) climate of the area. In hotter climates where water consumption is greater, exposure doses of fluoride need to be modified based on mean fluoride intake. Various cost-effective and simple procedures for water defluoridation techniques are already known, but the benefits of such techniques have not reached the rural affected population due to limitations. Therefore, there is a need to develop workable strategies to provide fluoride-safe drinking water to rural communities. The study investigated the geochemistry and occurrence of fluoride and its contamination in groundwater, human exposure, various adverse health effects, and possible remedial measures from fluoride toxicity effects.

  15. Structural diversity in lithium carbides

    NASA Astrophysics Data System (ADS)

    Lin, Yangzheng; Strobel, Timothy A.; Cohen, R. E.

    2015-12-01

    The lithium-carbon binary system possesses a broad range of chemical compounds, which exhibit fascinating chemical bonding characteristics, which give rise to diverse and technologically important properties. While lithium carbides with various compositions have been studied or suggested previously, the crystal structures of these compounds are far from well understood. In this work, we present the first comprehensive survey of all ground state (GS) structures of lithium carbides over a broad range of thermodynamic conditions, using ab initio density functional theory (DFT) crystal structure searching methods. Thorough searches were performed for 29 stoichiometries ranging from Li12C to LiC12 at 0 and 40 GPa. Based on formation enthalpies from optimized van der Waals density functional calculations, three thermodynamically stable phases (Li4C3 , Li2C2 , and LiC12) were identified at 0 GPa, and seven thermodynamically stable phases (Li8C , Li6C , Li4C , Li8C3 , Li2C , Li3C4 , and Li2C3 ) were predicted at 40 GPa. A rich diversity of carbon bonding, including monomers, dimers, trimers, nanoribbons, sheets, and frameworks, was found within these structures, and the dimensionality of carbon connectivity existing within each phase increases with increasing carbon concentration. We find that the well-known composition LiC6 is actually a metastable one. We also find a unique coexistence of carbon monomers and dimers within the predicted thermodynamically stable phase Li8C3 , and different widths of carbon nanoribbons coexist in a metastable phase of Li2C2 (Imm2). Interesting mixed sp2-sp3 carbon frameworks are predicted in metastable phases with composition LiC6.

  16. Determining the optimal fluoride concentration in drinking water for fluoride endemic regions in South India.

    PubMed

    Viswanathan, Gopalan; Jaswanth, A; Gopalakrishnan, S; Siva Ilango, S; Aditya, G

    2009-10-01

    Fluoride ion in drinking water is known for both beneficial and detrimental effects on health. The prevalence of fluorosis is mainly due to the intake of large quantities of fluoride through drinking water owing to more than 90% bioavailability. The objective of this study is to predict optimal fluoride level in drinking water for fluoride endemic regions by comprising the levels of fluoride and other water quality parameters in drinking water, prevalence of fluorosis, fluoride intake through water, food and beverages such as tea and coffee and also considering the progressive accumulation of fluoride in animal bones, by comparing with non fluoride endemic areas comprise of the same geological features with the aid of regression analysis. Result of this study shows that increase of fluoride level above 1.33 mg/l in drinking water increases the community fluorosis index (CFI) value more than 0.6, an optimum index value above which fluorosis is considered to be a public health problem. Regression plot between water fluoride and bone fluoride levels indicates that, every increase of 0.5mg/l unit of water fluoride level increases the bone fluoride level of 52 mg/kg unit within 2 to 3 years. Furthermore, the consumption of drinking water containing more than 0.65 mg/l of fluoride can raise the total fluoride intake per day more than 4 mg, which is the optimum fluoride dose level recommended for adults by the Agency for Toxic Substances and Disease Registry. From the result, the people in fluoride endemic areas in South India are advised to consume drinking water with fluoride level within the limit of 0.5 to 0.65 mg/l to avoid further fluorosis risk.

  17. Global affordability of fluoride toothpaste

    PubMed Central

    Goldman, Ann S; Yee, Robert; Holmgren, Christopher J; Benzian, Habib

    2008-01-01

    Objective Dental caries remains the most common disease worldwide and the use of fluoride toothpaste is a most effective preventive public health measure to prevent it. Changes in diets following globalization contribute to the development of dental caries in emerging economies. The aim of this paper is to compare the cost and relative affordability of fluoride toothpaste in high-, middle- and low-income countries. The hypothesis is that fluoride toothpaste is not equally affordable in high-, middle- and low-income countries. Methods Data on consumer prices of fluoride toothpastes were obtained from a self-completion questionnaire from 48 countries. The cost of fluoride toothpaste in high-, middle- and low-income countries was compared and related to annual household expenditure as well as to days of work needed to purchase the average annual usage of toothpaste per head. Results The general trend seems to be that the proportion of household expenditure required to purchase the annual dosage of toothpaste increases as the country's per capita household expenditure decreases. While in the UK for the poorest 30% of the population only 0.037 days of household expenditure is needed to purchase the annual average dosage (182.5 g) of the lowest cost toothpaste, 10.75 days are needed in Kenya. The proportion of annual household expenditure ranged from 0.02% in the UK to 4% in Zambia to buy the annual average amount of lowest cost toothpaste per head. Conclusion Significant inequalities in the affordability of this essential preventive care product indicate the necessity for action to make it more affordable. Various measures to improve affordability based on experiences from essential pharmaceuticals are proposed. PMID:18554382

  18. Dynamics of Fluoride Bioavailability in the Biofilms of Different Oral Surfaces after Amine Fluoride and Sodium Fluoride Application

    PubMed Central

    Naumova, Ella A.; Dickten, Christoph; Jung, Rico; Krauss, Florian; Rübesamen, Henrik; Schmütsch, Katharina; Sandulescu, Tudor; Zimmer, Stefan; Arnold, Wolfgang H.

    2016-01-01

    It was the aim of this study to investigate differences in fluoride bioavailability in different oral areas after the application of amine fluoride (AmF) and sodium fluoride (NaF). The null hypothesis suggested no differences in the fluoride bioavailability. The tongue coating was removed and biofilm samples from the palate, oral floor and cheeks were collected. All subjects brushed their teeth with toothpaste containing AmF or NaF. Specimens were collected before, as well as immediately after and at 30 and 120 minutes after tooth brushing. The fluoride concentration was determined. The area under the curve was calculated for each location and compared statistically. In the tongue coating, fluoride concentration increased faster after NaF application than after AmF application. After 30 minutes, the fluoride concentration decreased and remained stable until 120 minutes after AmF application and returned to baseline after NaF application. The difference between the baseline and the endpoint measurements was statistically significant. The fluoride concentration in the tongue coating remained at a higher level compared with the baseline for up to 120 minutes post-brushing. This may indicate that the tongue coating is a major reservoir for fluoride bioavailability. The results also indicate an unequal fluoride distribution in the oral cavity. PMID:26727989

  19. Formation of phosphate-containing calcium fluoride at the expense of enamel, hydroxyapatite and fluorapatite.

    PubMed

    Christoffersen, J; Christoffersen, M R; Arends, J; Leonardsen, E S

    1995-01-01

    During the caries process complex reactions involving calcium, phosphate, hydrogen and fluoride ions as main species take place. In this study the precipitation and dissolution reactions occurring in suspensions of enamel, hydroxyapatite (HAP) and fluorapatite (FAP) on addition of fluoride were investigated under well-defined conditions. pH and pF were monitored; calcium and phosphate concentrations were measured at selected times; the solid phases were examined by infra-red, X-ray diffraction and transmission electron microscopy. Precipitation of phosphate-containing calcium fluoride crystals, CaF2(P), can cause severe reduction in the calcium ion concentration and release of hydrogen ions from the precipitated phosphate. These reactions result in considerable dissolution of enamel, HAP and even of FAP. More of the added mineral dissolves with 50 mmol/l fluoride than with 10 mmol/l fluoride, mainly due to the greater reduction in calcium ion concentration. This work shows that phosphate-containing calcium fluoride is most likely an important compound to be considered in the caries process.

  20. Crystal structure of μ-fluorido-bis­{(η4-cyclo­octa­diene)[hexa­fluorido­anti­monato(V)]platinum(II)} hexa­fluorido­anti­monate(V) hydrogen fluoride 0.75-solvate1

    PubMed Central

    Seppelt, Konrad; Friedemann, Roland

    2016-01-01

    In the complex cation of the binuclear solvated title salt, [Pt2F(SbF6)2(C8H12)2]SbF6·0.75HF, an F atom bridges the two platinum(II) atoms with a bond angle of 123.3 (2)°. The corresponding Pt—F bond lengths are in the range of other fluorine-bridged binuclear platinum(II) complexes. Two of the three SbF6 − anions each coordinate with one F atom to one platinum(II) atom. Including the η4-bound cyclo­octa­diene (COD) ligands, the overall coordination sphere of each platinum(II) atom is square-planar. The third SbF6 − anion is not bound to the complex. Hydrogen fluoride is present in the crystal structure as a solvent disordered over three positions, each with an occupancy of 0.25. F⋯F distances of 2.5512 (7), 2.6076 (8) and 3.2215 (10) Å to surrounding SbF6 − anions are indicative of F—H⋯F hydrogen-bonding inter­actions although no H atoms could be localized for the disordered solvent mol­ecules. The resulting hydrogen-bonded network is three-dimensional. PMID:26870575