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Sample records for atoms li na

  1. Structure determination in 55-atom Li-Na and Na-K nanoalloys.

    Science.gov (United States)

    Aguado, Andrés; López, José M

    2010-09-01

    The structure of 55-atom Li-Na and Na-K nanoalloys is determined through combined empirical potential (EP) and density functional theory (DFT) calculations. The potential energy surface generated by the EP model is extensively sampled by using the basin hopping technique, and a wide diversity of structural motifs is reoptimized at the DFT level. A composition comparison technique is applied at the DFT level in order to make a final refinement of the global minimum structures. For dilute concentrations of one of the alkali atoms, the structure of the pure metal cluster, namely, a perfect Mackay icosahedron, remains stable, with the minority component atoms entering the host cluster as substitutional impurities. At intermediate concentrations, the nanoalloys adopt instead a core-shell polyicosahedral (p-Ih) packing, where the element with smaller atomic size and larger cohesive energy segregates to the cluster core. The p-Ih structures show a marked prolate deformation, in agreement with the predictions of jelliumlike models. The electronic preference for a prolate cluster shape, which is frustrated in the 55-atom pure clusters due to the icosahedral geometrical shell closing, is therefore realized only in the 55-atom nanoalloys. An analysis of the electronic densities of states suggests that photoelectron spectroscopy would be a sufficiently sensitive technique to assess the structures of nanoalloys with fixed size and varying compositions. PMID:20831313

  2. Calculation of the elastic collision properties of Na and Li atoms at ultracold temperature

    Institute of Scientific and Technical Information of China (English)

    Zhang Ji-Cai; Zhang Ying; Du Bing-Ge; Sun Jin-Feng

    2009-01-01

    This paper firstly reports a theoretical study of elastic scattering properties in a mixture of 23Na and 7Li atoms at cold and ultracold temperatures in detail.Based on the new constructed accurate singlet X1∑+g and the triplet a3∑+u states interatomic potentials for 23Na7Li mixture,it calculates the scattering lengths and the effective ranges by three computational methods,and obtains good agreements.Using the mass scaling method,it also calculates 23Na6Li scattering lengths and s-wave and total elastic cross sections,whose rich resonance structures were found and interpreted in terms of quasibound diatomic levels trapped behind a centrifugal barrier.

  3. Construction of embedded-atom-method interatomic potentials for alkaline metals (Li, Na, and K) by lattice inversion

    International Nuclear Information System (INIS)

    The lattice-inversion embedded-atom-method interatomic potential developed previously by us is extended to alkaline metals including Li, Na, and K. It is found that considering interatomic interactions between neighboring atoms of an appropriate distance is a matter of great significance in constructing accurate embedded-atom-method interatomic potentials, especially for the prediction of surface energy. The lattice-inversion embedded-atom-method interatomic potentials for Li, Na, and K are successfully constructed by taking the fourth-neighbor atoms into consideration. These angular-independent potentials markedly promote the accuracy of predicted surface energies, which agree well with experimental results. In addition, the predicted structural stability, elastic constants, formation and migration energies of vacancy, and activation energy of vacancy diffusion are in good agreement with available experimental data and first-principles calculations, and the equilibrium condition is satisfied. (atomic and molecular physics)

  4. Construction of embedded-atom-method interatomic potentials for alkaline metals (Li, Na, and K) by lattice inversion

    Institute of Scientific and Technical Information of China (English)

    Yuan Xiao-Jian; Chen Nan-Xian; Shen Jiang

    2012-01-01

    The lattice-inversion embedded-atom-method interatomic potential developed previously by us is extended to alkaline metals including Li,Na,and K.It is found that considering interatomic interactions between neighboring atoms of an appropriate distance is a matter of great significance in constructing accurate embedded-atom-method interatomic potentials,especially for the prediction of surface energy.The lattice-inversion embedded-atom-method interatomic potentials for Li,Na,and K are successfully constructed by taking the fourth-neighbor atoms into consideration.These angular-independent potentials markedly promote the accuracy of predicted surface energies,which agree well with experimental results.In addition,the predicted structural stability,elastic constants,formation and migration energies of vacancy,and activation energy of vacancy diffusion are in good agreement with available experimental data and first-principles calculations,and the equilibrium condition is satisfied.

  5. Interaction of antiprotons with Rb atoms and a comparison of antiproton stopping powers of the atoms H, Li, Na, K, and Rb

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Fischer, Nicolas; Saenz, Alejandro

    Ionization and excitation cross sections as well as electron-energy spectra and stopping powers of the alkali metal atoms Li, Na, K, and Rb colliding with antiprotons were calculated using a time-dependent channel-coupling approach. An impact-energy range from 0.25 to 4000 keV was considered. The...... target atoms are treated as effective one-electron systems using a model potential. The results are compared with calculated cross sections for antiproton-hydrogen atom collisions....

  6. Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

    DEFF Research Database (Denmark)

    Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.;

    2002-01-01

    We measure angle differential cross sections (DCS) in Li+ + Na --> Li + Na+ electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target...... quantum scattering amplitudes are derived by the eikonal method. The resulting angle-differential electron transfer cross sections and their diffraction patterns agree with the experimental level-to-level results over most scattering angles in the energy range....

  7. First-principles study of ternary graphite compounds cointercalated with alkali atoms (Li, Na, and K) and alkylamines towards alkali ion battery applications

    Science.gov (United States)

    Ri, Gum-Chol; Yu, Chol-Jun; Kim, Jin-Song; Hong, Song-Nam; Jong, Un-Gi; Ri, Mun-Hyok

    2016-08-01

    First-principles calculations were carried out to investigate the structural, energetic, and electronic properties of ternary graphite compounds cointercalated with alkali atoms (AM = Li, Na, and K) and normal alkylamine molecules (nCx; x = 1, 2, 3, 4), denoted as AM-nCx-GICs. From the optimization of the orthorhombic unit cells for the crystalline compounds, it was found that, with the increase in the atomic number of alkali atoms, the layer separations decrease in contrast to AM-GICs, while the bond lengths between alkali atoms and graphene layer, and nitrogen atom of alkylamine increase. The calculated formation energies and interlayer binding energies of AM-nC3-GICs indicate that the compounds is increasingly stabilized from Li to K, and the energy barriers for migration of alkali atoms suggest that alkali cation with larger ionic radius diffuses more smoothly in graphite, being similar to AM-GICs. Through the analysis of electronic properties, it was established that more extent of electronic charge is transferred from more electropositive alkali atom to the carbon ring of graphene layer, and the hybridization of valence electron orbitals between alkylamine molecules and graphene layer is occurred.

  8. Determination of Ca, Mg, Na, Cd, Cu, Fe, K, Li and Zn in acid mine and reference water samples by inductively coupled plasma atomic fluorescence spectrometry

    Science.gov (United States)

    Sanzolone, R.F.; Meier, A.L.

    1986-01-01

    An inductively coupled plasma atomic fluorescence spectrometric (ICP-AFS) method was used for the determination of nine elements in natural water. Reference and acid mine water samples were analysed by this method to demonstrate its usefulness for hydrogeochemical exploration. The elements were determined in two groups based on the compatibility of operating conditions and consideration of element abundance levels in natural water. Ca, Mg and Na were determined as a group using one set of instrumental conditions and a 1 + 99 dilution of the sample, and Cd, Cu, Fe, K, Li and Zn were determined using another set of conditions and the undiluted sample. The detection limits for the elements are as follows: Ca, 1.4; Mg, 1.7; Na, 2.0; Cd, 1.8; Cu, 6.2; Fe, 15.8; K, 3.5; Li, 0.3; and Zn, 1.2 ng m1-1. Each element has a linear range spanning about four orders of magnitude. The method has good precision and accuracy, as shown by statistics on replicate analyses and by the agreement between values obtained and those recommended for the reference water samples, and also those obtained by atomic absorption spectrometry for the acid mine water samples.

  9. Structural and electronic properties of AB- and AA-stacking bilayer-graphene intercalated by Li, Na, Ca, B, Al, Si, Ge, Ag, and Au atoms

    Science.gov (United States)

    Tayran, Ceren; Aydin, Sezgin; Çakmak, Mehmet; Ellialtıoğlu, Şinasi

    2016-04-01

    The structural and electronic properties of X (=Li, Na, Ca, B, Al, Si, Ge, Ag, and Au)-intercalated AB- and AA-stacking bilayer-graphene have been investigated by using ab initio density functional theory. It is shown that Boron (Lithium)-intercalated system is energetically more stable than the others for the AB (AA) stacking bilayer-graphene systems. The structural parameters, electronic band structures, and orbital nature of actual interactions are studied for the relaxed stable geometries. It is seen that the higher the binding energy, the smaller is the distance between the layers, in these systems. The electronic band structures for these systems show that different intercalated atoms can change the properties of bilayer-graphene differently. For qualitative description of the electronic properties, the metallicities of the systems are also calculated and compared with each other. The Mulliken analysis and electron density maps clearly indicate that the interactions inside a single layer (intralayer interactions) are strong and highly covalent, while the interactions between the two layers (interlayer interactions) are much weaker.

  10. Measurement of surface phonon dispersion relations for LiF, NaF, and KCl through energy-analysed inelastic scattering of a helium atomic beam

    International Nuclear Information System (INIS)

    A crystal surface terminates abruptly one dimension of lattice periodicity, constituting a lattice defect with concomitant localized modes of vibration, termed surface phonons. Such surface phonons have previously been investigated in the long wavelength, non-dispersive regime. The present work reports the first observation of surface phonons in the short wavelength, dispersive range. The data allow for the first time a surface phonon dispersion curve to be plotted completely from origin to edge of the surface Brillouin zone. Measurements were made of phonons along the (anti GAMMA anti M) and (anti GAMMA anti X) azimuths of the LiF(001) surface and along the azimuth of NaF(001) and KC1(001) surfaces. The results are in substantial agreement with theoretical predictions, although for LiF the measured Rayleigh dispersion curve at M lies appreciably below the theoretical value, possibly reflecting the effects of surface relaxation. (orig.)

  11. Endurance testing with Li/Na electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Ong, E.T.; Remick, R.J.; Sishtla, C.I. [Institute of Gas Technology, Des Plaines, IL (United States)

    1996-12-31

    The Institute of Gas Technology (IGT), under subcontract to M-C Power Corporation under DOE funding, has been operating bench-scale fuel cells to investigate the performance and endurance issues of the Li/Na electrolyte because it offers higher ionic conductivity, higher exchange current densities, lower vapor pressures, and lower cathode dissolution rates than the Li/K electrolyte. These cells have continued to show higher performance and lower decay rates than the Li/K cells since the publication of our two previous papers in 1994. In this paper, test results of two long-term 100-cm{sup 2} bench scale cells are discussed. One cell operated continuously at 160 mA/cm{sup 2} for 17,000 hours with reference gases (60H{sub 2}/20CO{sub 2}/20H{sub 2}O fuel at 75% utilization and 30CO{sub 2}/70 air oxidant humidified at room temperature at 50% utilization). The other cell operated at 160 mA/cm{sup 2} for 6900 hours at 3 atm with system gases (64H{sub 2}/16CO{sub 2}/20H{sub 2}O at 75% utilization and an M-C Power system-defined oxidant at 40% utilization). Both cells have shown the highest performance and longest endurance among IGT cells operated to date.

  12. High performance MCFC using Li/Na electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Donado, R.A.; Ong, E.T.; Sishtla, C.I.

    1995-08-01

    The substitution of a lithium/ sodium carbonate (Li/Na) mixture for the lithium/potassium carbonate (Li/K) electrolyte used in MCFCs holds the promise of higher ionic conductivity, higher exchange current density at both electrodes, lower vapor pressure, and lower cathode dissolution rates. However, when the substitution is made in cells optimized for use with the Li/K electrolyte, the promised increase in performance is not realized. As a consequence the literature contains conflicting data with regard to the performance, compositional stability, and chemical reactivity of the Li/Na electrolyte. Experiments conducted at the Institute of Gas Technology (IGT) concluded that the source of the problem is the different wetting characteristics of the two electrolytes. Electrode pore structures optimized for use with Li/K do not work well with Li/Na. Using proprietary methods and materials, IGT was able to optimize a set of electrodes for the Li/Na electrolyte. Experiments conducted in bench-scale cells have confirmed the superior performance of the Li/Na electrolyte compared to the Li/K electrolyte. The Li/Na cells exhibited a 5 to 8 percent improvement in overall performance, a substantial decrease in the rate of cathode dissolution, and a decreased decay rate. The longest running cell has logged over 13,000 hours of operation with a decay rate of less than 2 mV/1000 hours.

  13. Comparative Computational Study of the Energetics of Li, Na, and Mg Storage in Amorphous and Crystalline Silicon

    OpenAIRE

    Legrain, Fleur; Malyi, Oleksandr I.; Manzhos, Sergei

    2014-01-01

    To assess the potential of amorphous Si (a-Si) as an anode for Li, Na, and Mg-ion batteries, the energetics of Li, Na, and Mg atoms in a-Si are computed from first-principles and compared to those in crystalline Si (c-Si). It is shown that Si preamorphization increases the average anode voltage and reduces the volume expansion of the anode during the insertion of the metal atoms. Analysis of computed formation energies of Li, Na, and Mg defects in a-Si and c-Si suggests that the energetics of...

  14. Atomistic Conversion Reaction Mechanism of WO3 in Secondary Ion Batteries of Li, Na, and Ca.

    Science.gov (United States)

    He, Yang; Gu, Meng; Xiao, Haiyan; Luo, Langli; Shao, Yuyan; Gao, Fei; Du, Yingge; Mao, Scott X; Wang, Chongmin

    2016-05-17

    Intercalation and conversion are two fundamental chemical processes for battery materials in response to ion insertion. The interplay between these two chemical processes has never been directly seen and understood at atomic scale. Here, using in situ HRTEM, we captured the atomistic conversion reaction processes during Li, Na, Ca insertion into a WO3 single crystal model electrode. An intercalation step prior to conversion is explicitly revealed at atomic scale for the first time for Li, Na, Ca. Nanoscale diffraction and ab initio molecular dynamic simulations revealed that after intercalation, the inserted ion-oxygen bond formation destabilizes the transition-metal framework which gradually shrinks, distorts and finally collapses to an amorphous W and Mx O (M=Li, Na, Ca) composite structure. This study provides a full atomistic picture of the transition from intercalation to conversion, which is of essential importance for both secondary ion batteries and electrochromic devices. PMID:27071488

  15. Transport properties derived from ion-atom collisions: 6Li-6Li+ and 6Li-7Li+ Cases

    Science.gov (United States)

    Bouledroua, Moncef; Bouchelaghem, Fouzia; LPR Team

    2014-10-01

    This investigation treats quantum-mechanically the ion- atom collisions and computes the transport coefficients, such as the coefficients of mobility and diffusion. For the case of lithium, the calculations start by determining the gerade and ungerade potential curves through which ionic lithium approaches ground lithium. Then, by considering the isotopic effects and nuclear spins, the elastic and charge-transfer cross sections are calculated for the case of 6Li+and7Li+ colliding with 6Li. Finally, the temperature-dependent diffusion and mobility coefficients are analyzed, and the results are contrasted with those obtained from literature. The main results of this work have been recently published in. This work has been realized within the frames of the CNEPRU Project D01120110036 of the Algerian Ministry of Higher Education.

  16. A personal thermoluminescence dosimeter using LiF:Mg,Cu,Na,Si detectors for photon fields

    International Nuclear Information System (INIS)

    A new personal thermoluminescence (TL) dosimeter for photon fields using LiF:Mg,Cu,Na,Si TL detector was developed by taking advantage of its dosimetric properties including energy dependencies. Solid pellet type LiF:Mg,Cu,Na,Si detector was developed and fabricated at Korea Atomic Energy Research Institute (KAERI) and has been studied on its dosimetric properties such as TL grow curve, dose response, energy response and reusability. Its dosimetric properties show the feasibility of application of LiF:Mg,Cu,Na,Si TL detector to personal dosimetry fields. A new dosimeter using LiF:Mg,Cu,Na,Si TL detector was designed and tested through irradiation experiments. This multi-element TL dosimeter allows the measurement of a personal dose equivalent Hp(d) in photon fields. Based on the experimental results of the proposed dosimeter, it was demonstrated that a personal TL dosimeter using sintered LiF:Mg,Cu,Na,Si TL detector is appropriate to estimate personal dose equivalent for wide range energy of photon fields

  17. Laser trapping of 21Na atoms

    International Nuclear Information System (INIS)

    This thesis describes an experiment in which about four thousand radioactive 21Na (tl/2 = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped 21Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of 21Na → 21Ne + Β+ + ve, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, 21Na atoms were produced by bombarding 24Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The 21Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined

  18. Effect of Li atoms in solid solution on recrystallization and texture development in model Al-0.8%Li alloy

    International Nuclear Information System (INIS)

    In this work the influence of Li atoms in solid solution on plastic deformation, recrystallization and texture development in model Al-0.8%Li alloy was investigated. It was stated that Li atoms lead to shear band formation during cold rolling. Moreover, in compare with traditional aluminium alloys, the interactions between grain boundaries and Li atoms causes a continuous recrystallization and the formation of a different texture. (author)

  19. Effect of Li atoms in solid solution on recrystallization and texture development in model Al-0.8%Li alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowska, M.; Mizera, J.; Wawrzykowski, J.W. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw (Poland)

    1995-12-31

    In this work the influence of Li atoms in solid solution on plastic deformation, recrystallization and texture development in model Al-0.8%Li alloy was investigated. It was stated that Li atoms lead to shear band formation during cold rolling. Moreover, in compare with traditional aluminium alloys, the interactions between grain boundaries and Li atoms causes a continuous recrystallization and the formation of a different texture. (author). 6 refs, 6 figs.

  20. Insights into stability, electronic properties, defect properties and Li ions migration of Na, Mg and Al-doped LiVPO4F for cathode materials of lithium ion batteries: A first-principles investigation

    Science.gov (United States)

    Lv, Xiaojun; Xu, Zhenming; Li, Jie; Chen, Jiangan; Liu, Qingsheng

    2016-07-01

    The effects of Na, Mg and Al doping on the structure, electronic property, defect property and Li ions migration of LiVPO4F were investigated by the first-principles method. Calculations show that the processes of forming Li0.875Na0.125VPO4F, α- and β-LiMg0.375V0.75PO4F, α- and β-LiAl0.125V0.875PO4F are all feasible. Na, Mg and Al doping significantly improve the electrical conductivity of LiVPO4F and simultaneously maintain their structural stability attributing to the reduction of band gaps through variations of V-3d spin up orbitals. Li vacancy defects of LiVPO4F are not ignorable, and vacancy defects with a lower activation energy for Li atom are far more likely to occur than Frenkel defects for Li and vacancy defects for other atoms. For pristine LiVPO4F, path D along [0.012 0 . 17 ̅ 0.572] direction is found to have the lowest activation energy of 0.418 eV, suggesting that anisotropic nature of Li ion conduction and LiVPO4F is a one-dimensional (1D)-ion conductor. The corresponding diffusion coefficient was estimated to be 2.82×10-9 cm2/s, which is in good agreement with those experimental values.

  1. Toward Triplet Ground State NaLi Molecules

    Science.gov (United States)

    Ebadi, Sepehr; Jamison, Alan; Rvachov, Timur; Jing, Li; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    The NaLi molecule is expected to have a long lifetime in the triplet ground-state due to its fermionic nature, large rotational constant, and weak spin-orbit coupling. The triplet state has both electric and magnetic dipole moments, affording unique opportunities in quantum simulation and ultracold chemistry. We have mapped the excited state NaLi triplet potential by means of photoassociation spectroscopy. We report on this and our further progress toward the creation of the triplet ground-state molecules using STIRAP. NSF, ARO-MURI, Samsung, NSERC.

  2. Li and Na Co-decorated carbon nitride nanotubes as promising new hydrogen storage media

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu Sheng [Center of Clean Energy and Quantum Structures, and School of Physics and Engineering, Zhengzhou University, Zhengzhou, Henan, 450052 (China); College of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou, Henan, 450011 (China); Li, Meng; Wang, Fei; Sun, Qiang [Center of Clean Energy and Quantum Structures, and School of Physics and Engineering, Zhengzhou University, Zhengzhou, Henan, 450052 (China); Jia, Yu, E-mail: jiayu@zzu.edu.cn [Center of Clean Energy and Quantum Structures, and School of Physics and Engineering, Zhengzhou University, Zhengzhou, Henan, 450052 (China)

    2012-01-09

    The capacity of Li and Na co-decorated carbon nitride nanotube (CNNT) for hydrogen storage is studied using first-principles density functional theory. The results show that with two H{sub 2} molecules attached to per Li and four H{sub 2} molecules per Na the Li and Na co-decorated CNNT gains a gravimetric density of H{sub 2} as high as 9.09 wt% via electrostatic interaction without the clustering of the deposited metal atoms (at T=0 K). The average adsorption energy of hydrogen molecule is in the range of 0.09–0.22 eV/H{sub 2}, which is suitable for practical hydrogen storage at ambient temperatures. -- Highlights: ► Li and Na co-decorated carbon nitride nanotubes as hydrogen storage media. ► The gravimetric density of H{sub 2} is 9.09 wt%. ► The average adsorption energy of hydrogen molecule is 0.09–0.22 eV/H{sub 2}. ► It can operate under ambient thermodynamic conditions.

  3. On the hyperfine structures of the ground state(s) in the ${}^{6}$Li and ${}^{7}$Li atoms

    CERN Document Server

    Frolov, Alexei M

    2016-01-01

    Hyperfine structure of the ground $2^{2}S-$states of the three-electron atoms and ions is investigated. By using our recent numerical values for the doublet electron density at the atomic nucleus we determine the hyperfine structure of the ground (doublet) $2^{2}S-$state(s) in the ${}^{6}$Li and ${}^{7}$Li atoms.

  4. Three Dimensional Thermoluminescence Emission Spectra of the LiF:Mg,Cu,Na,Si Thermoluminescent Materials

    International Nuclear Information System (INIS)

    A new sintered pellet-type LiF: Mg,Cu,Na,Si TL detector which has a high sensitivity and good reusability, named KLT-300 (KAERI LiF:Mg,Cu,Na,Si TL detector), was recently developed by the variation of dopant concentrations and the parameters for the preparation procedure at the Korea Atomic Energy Research Institute (KAERI). To establish a possibility for an improvement in the dosimetric properties of the LiF: Mg, Cu, Na, Si TL detectors, a study to understand the mechanism of the TL for the TL material is essential. The simple model of the mechanism of the TL comprises of three steps: the trapping of the charge carriers during an irradiation with ionizing radiation, the release of the charge carriers out of the traps due to thermal heating, and the capture of the charge carriers in the luminescent centers under a photon emission. The TL glow curve, the emitted light as a function of the temperature, can give some information on the trapping centers of the TL material, but cannot give the information for step. To understand the mechanism of a TL for a TL material, the information for step should be provided. A possible technique to obtain information for the step in the TL mechanism is the measurement of the light emission during a heating of the sample as a function of the temperature and wavelength (three-dimensional TL spectra). In this paper, the TL spectra for the four kinds of samples which had a different composition of the dopants: LiF: Mg,Cu,Na,Si (MCNS); LiF: Mg,Cu (MC); LiF: Mg,Na,Si (MNS) and LiF: Cu,Na,Si (CNS) were presented for the study. The detailed results of the analysis for the three-dimensional TL spectra of the LiF: Mg,Cu,Na,Si TL materials which have various concentrations of the dopants is reported as a comprehensive study to understand the TL mechanism for the material. The TL spectra were fitted by Gaussian curves to establish the components of the spectra

  5. Epitaxial thin film growth of LiH using a liquid-Li atomic template

    Energy Technology Data Exchange (ETDEWEB)

    Oguchi, Hiroyuki, E-mail: oguchi@nanosys.mech.tohoku.ac.jp [Department of Nanomechanics, Tohoku University, Sendai 980-8579 (Japan); Micro System Integration Center (muSIC), Tohoku University, Sendai 980-0845 (Japan); Ikeshoji, Tamio; Orimo, Shin-ichi [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577 (Japan); Ohsawa, Takeo; Shiraki, Susumu; Hitosugi, Taro [Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577 (Japan); Kuwano, Hiroki [Department of Nanomechanics, Tohoku University, Sendai 980-8579 (Japan)

    2014-11-24

    We report on the synthesis of lithium hydride (LiH) epitaxial thin films through the hydrogenation of a Li melt, forming abrupt LiH/MgO interface. Experimental and first-principles molecular dynamics studies reveal a comprehensive microscopic picture of the crystallization processes, which sheds light on the fundamental atomistic growth processes that have remained unknown in the vapor-liquid-solid method. We found that the periodic structure that formed, because of the liquid-Li atoms at the film/MgO-substrate interface, serves as an atomic template for the epitaxial growth of LiH crystals. In contrast, films grown on the Al{sub 2}O{sub 3} substrates indicated polycrystalline films with a LiAlO{sub 2} secondary phase. These results and the proposed growth process provide insights into the preparation of other alkaline metal hydride thin films on oxides. Further, our investigations open the way to explore fundamental physics and chemistry of metal hydrides including possible phenomena that emerge at the heterointerfaces of metal hydrides.

  6. Epitaxial thin film growth of LiH using a liquid-Li atomic template

    International Nuclear Information System (INIS)

    We report on the synthesis of lithium hydride (LiH) epitaxial thin films through the hydrogenation of a Li melt, forming abrupt LiH/MgO interface. Experimental and first-principles molecular dynamics studies reveal a comprehensive microscopic picture of the crystallization processes, which sheds light on the fundamental atomistic growth processes that have remained unknown in the vapor-liquid-solid method. We found that the periodic structure that formed, because of the liquid-Li atoms at the film/MgO-substrate interface, serves as an atomic template for the epitaxial growth of LiH crystals. In contrast, films grown on the Al2O3 substrates indicated polycrystalline films with a LiAlO2 secondary phase. These results and the proposed growth process provide insights into the preparation of other alkaline metal hydride thin films on oxides. Further, our investigations open the way to explore fundamental physics and chemistry of metal hydrides including possible phenomena that emerge at the heterointerfaces of metal hydrides

  7. Quantum phase transition and entanglement in Li atom system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By use of the exact diagonalization method, the quantum phase transition and en- tanglement in a 6-Li atom system are studied. It is found that entanglement appears before the quantum phase transition and disappears after it in this exactly solvable quantum system. The present results show that the von Neumann entropy, as a measure of entanglement, may reveal the quantum phase transition in this model.

  8. Atomic resolution of Lithium Ions in LiCoO

    Energy Technology Data Exchange (ETDEWEB)

    Shao-Horn, Yang; Croguennec, Laurence; Delmas, Claude; Nelson, Chris; O' Keefe, Michael A.

    2003-03-18

    LiCoO2 is the most common lithium storage material for lithium rechargeable batteries, used widely to power portable electronic devices such as laptop computers. Lithium arrangements in the CoO2 framework have a profound effect on the structural stability and electrochemical properties of LixCoO2 (0 < x < 1), however, probing lithium ions has been difficult using traditional X-ray and neutron diffraction techniques. Here we have succeeded in simultaneously resolving columns of cobalt, oxygen, and lithium atoms in layered LiCoO2 battery material using experimental focal series of LiCoO2 images obtained at sub-Angstrom resolution in a mid-voltage transmission electron microscope. Lithium atoms are the smallest and lightest metal atoms, and scatter electrons only very weakly. We believe our observations of lithium to be the first by electron microscopy, and that they show promise to direct visualization of the ordering of lithium and vacancy in LixCoO2.

  9. Theoretical study on the correlation between the nature of atomic Li intercalation and electrochemical reactivity in TiS2 and TiO2.

    Science.gov (United States)

    Kim, Yang-Soo; Kim, Hee-Jin; Jeon, Young-A; Kang, Yong-Mook

    2009-02-12

    The electronic structures of LiTiS(2) and LiTiO(2) (having alpha-NaFeO(2) structure) have been investigated using discrete variational Xalpha molecular orbital methods. The alpha-NaFeO(2) structure is the equilibrium structure for LiCoO(2), which is widely used as a commercial cathode material for lithium secondary batteries. This study especially focused on the charge state of Li ions and the magnitude of covalency around Li ions. When the average voltage of lithium intercalation was calculated using pseudopotential methods, the average intercalation voltage of LiTiO(2) (2.076 V) was higher than that of LiTiS(2) (1.958 V). This can be explained by the differences in Mulliken charge of lithium and the bond overlap population between the intercalated Li ions and anion in LiTiO(2) as well as LiTiS(2). The Mulliken charge, which is the ionicity of Li atom, was approximately 0.12 in LiTiS(2), and the bond overlap population (BOP) indicating the covalency between Ti and S was about 0.339. When compared with the BOP (0.6) of C-H, which is one of the most famous example of covalent bonding, the intercalated Li ions in LiTiS(2) tend to form a quite strong covalent bond with the host material. In contrast, the Mulliken charge of lithium was about 0.79, which means that Li is fully ionized and the BOP, the covalency between Ti and O, was 0.181 in LiTiO(2). Because of the high ionicity of Li and the weak covalency between Ti and the nearest anion, LiTiO(2) has a higher intercalation voltage than LiTiS(2). PMID:19138089

  10. Hydrogen storage properties of Na-Li-Mg-Al-H complex hydrides

    International Nuclear Information System (INIS)

    Lightweight complex hydrides have attracted attention for their high storage hydrogen capacity. NaAlH4 has been widely studied as a hydrogen storage material for its favorable reversible operating temperature and pressure range for automotive fuel cell applications. The increased understanding of NaAlH4 has led to an expanded search for high capacity materials in mixed alkali and akali/alkaline earth alanates. In this study, promising candidates in the Na-Li-Mg-Al-H system were evaluated using a combination of experimental chemistry, atomic modeling, and thermodynamic modeling. New materials were synthesized using solid state and solution based processing methods. Their hydrogen storage properties were measured experimentally, and the test results were compared with theoretical modeling assessments

  11. Theoretical study of 'Mixed' ligands superhalogens: Cl-M-NO3 (M = Li, Na, K)

    Science.gov (United States)

    Zhao, Xinghua; Liu, Weihui; Wang, Jiesheng; Li, Chun; Yuan, Guang

    2016-08-01

    MCl2-, M(NO3)2-, and (Cl-M-NO3)- (M = Li, Na, K) species are systematically investigated using the density functional theory. In all the cases studied, the vertical detachment energies (VDEs) exceed the electron affinity of chlorine atom, leading to the conclusion that MCl2-, M(NO3)2- and (Cl-M-NO3)- are superhalogens. The VDEs of (Cl-M-NO3)- are between that of MCl2- and M(NO3)2-, showing that replacing one ligand with a larger electronegative ligand leads to the higher VDE. Superhalogens with suitable VDEs can be built by using different ligands.

  12. Na+ and Li+ NASICON Superionic Conductors Thick Films

    Science.gov (United States)

    Perthuis, H.; Velasco, G.; Colomban, Ph.

    1984-05-01

    For microionic applications, superionic conductors have been elaborated in the form of thick films, using silk-screen printable powders. Na3Zr2Si2PO12, Na3.1Zr1.55Si2.3P0.7O11 and Li0.8Zr1.8Ta0.2(PO4)3 compositions are synthesized by a sol-gel process involving hydrolysis-polycondensation reactions of metal-organic alcoholic solutions. A thermal treatment (600°C-800°C) allows to obtain very fine particles (Inks are prepared with these powders, an organic binder, volatile fluidifying agents and mineralizers. The layers, about 50 μm in thickness, are achieved by successive deposits and sinterings (950°C-1050°C) onto alumina substrates. Films conductivity is determined by the complex impedance method. Values measured at 300°C (Na+: σ˜10-2 Ω-1cm-1, EA{=}0.25 eV, Li+: σ˜5 10-4 Ω-1cm-1, EA{=}0.5 eV) reach those obtained with well-densified ceramics. An anisotropic behaviour related to microstructure is pointed out.

  13. Na-Li-[V3O8] insertion electrodes: Structures and diffusion pathways

    International Nuclear Information System (INIS)

    The potential insertion-electrode compounds Na1.2[V3O8] (NaV) and Na0.7Li0.7[V3O8] (NaLiV) were synthesized from mixtures of Na2CO3, Li2CO3 and V2O5, which were melted at 750o and subsequently cooled to room temperature. The structures of NaV and LiV contain sheets of polymerized (VO n ) polyhedra, which are topologically identical to the sheet of polymerized polyhedra in Li1.2[V3O8] (LiV). Vanadium occurs in three different coordination environments: [2+3] V(1), [2+2+2] V(2) and [1+4+1] V(3). Calculated bond-valence sums indicate that V4+ occurs preferentially at the V(3) site, which agrees with the general observation that [6]-coordinated V4+ prefers [1+4+1]-rather than [2+2+2]-coordination. The M-cations Na and Li occur at three distinct sites, M(1), M(2) and M(3) between the vanadate sheets. The M(1)-site is fully occupied and has octahedral coordination. The M(2) sites are partly occupied in NaV and NaLiV, in which they occur in [4]- and [6]-coordination, respectively. Li partly occupies the M(3) site in NaLiV, in which it occurs in [3]-coordination. The M(2) and M(3) sites in NaLiV occur closer to the vanadate sheets than the M(2) sites in NaV and LiV. The shift in these cation positions is a result of the larger distance between the vanadate sheets in NaLiV than in LiV, which forces interstitial Li to move toward one of the vanadate sheets to satisfy its coordination requirements. Bond-valence maps for the interstitial cations Na and Li are presented for NaV, NaLiV and LiV. These maps are used to determine other potential cation positions in the interlayer and to map the regions of the structure where the Na and Li have their bond-valence requirements satisfied. These regions are potential pathways for Na and Li diffusion in these structures, and are used to explain chemical diffusion properties of Na and Li in the Na-Li-[V3O8] compounds. - Graphical abstract: Bond-valence map for Li in Na0.7Li0.7[V3O8]. Contour lines representing the bond-valence sum of 1

  14. The interaction of atoms with LiF(001) revisited

    CERN Document Server

    Miraglia, J E

    2016-01-01

    Pairwise additive potentials for multielectronic atoms interacting with a LiF(001) surface are revisited by including an improved description of the electron density associated with the different lattice sites, as well as non-local electron density contributions. Within this model, the electron distribution around each ionic site of the crystal is described by means of an onion approach that accounts for the influence of the Madelung potential. From such densities, binary interatomic potentials are then derived by using well-known non-local functionals for the kinetic, exchange and correlation terms. Rumpling and long-range contributions due to projectile polarization and van der Waals forces are also included in an analogous fashion. We apply this pairwise additive approximation to evaluate the interaction potential between closed-shell - He, Ne, Ar, Kr, and Xe - and open-shell - N, S, and Cl - atoms and the LiF surface, analyzing the relative importance of the different contributions. The performance of the...

  15. Electron-Stimulated Emission of Na Atoms from NaCl Nanocube Corners

    OpenAIRE

    Ceresoli, D.; Zykova-Timan, T.; Tosatti, E.

    2006-01-01

    We performed first principles density functional calculations and simulations of magic-size neutral NaCl nanocubes, and computed the the extraction of a Na neutral corner atom after donating an electron. The atomic structure of the resulting Na corner vacancy is presented.

  16. Synthesis, crystal structures and optical properties of two congruent-melting isotypic diphosphates: LiM3P2O7 (M=Na, K)

    International Nuclear Information System (INIS)

    Two new isotypic diphosphates, LiNa3P2O7 (1) and LiK3P2O7 (2), have been synthesized by conventional solid-state reaction. The single-crystal X-ray structural analyses have shown that they crystallize in the orthorhombic space group C2221 (No. 20) with the unit cells: a=5.4966(2) Å, b=9.1365(4) Å, c=12.2764(5) Å for compound 1 and a=6.0373(14) Å, b=9.339(2) Å, c=13.292(3) Å for compound 2. The LiM3P2O7 (M=Na, K) consist of two-dimensional [LiP2O7]3− layers, which are composed by LiO4 tetrahedral and diphosphate groups, the Na or K atoms are filled in the interlayers and balance the charge. Second harmonic generation (SHG) on powder samples have been measured using Kurtz and Perry techniques. Thermal analyses, IR spectroscopy, UV–vis–NIR diffuse reflectance spectra, and band structure calculations are performed on the reported compounds. - Graphical Abstract: LiM3P2O7 (M=Na, K) consists of a two-dimensional infinite [LiP2O7]3− layer, which is composed by LiO4 tetrahedra and diphosphate groups. Highlights: ► LiNa3P2O7 and LiK3P2O7 are new compounds in the Li2O–M2O (M=Na, K)–P2O5 systems. ► Crystal structures of LiNa3P2O7 and LiK3P2O7 consist of two-dimensional [LiP2O7]3− layers. ► LiNa3P2O7 and LiK3P2O7 are congruent melting compounds.

  17. Application of an electro-optical modulator in inelastic collision studies with laser-excited Na*(3p) atoms

    International Nuclear Information System (INIS)

    In atomic collision experiments with laser-excited target atoms it is often desirable to maximize the fraction f* of excited atoms. In the case of Na atoms pumped by a single mode CW dye laser radiation several effects including hyperfine pumping limit f* to about 10%. Using two side-bands of laser radiation, produced by means of an electro-optical modulator (phase modulation of laser radiation by a LiTaO3 crystal in a microwave field) transitions from both hyperfine ground states of Na can be pumped simultaneously. In this way a significant increase of the fraction of excited Na atoms in the 32P states to typically 30% could be achieved. The advantage of using an electro-optical modulator is demonstrated for the case of state-selective single electron capture studies of the He2+-Na*(3p) collision system. (author)

  18. Atomic structure and one-dimensional ionic conductivity of LiB3O5

    International Nuclear Information System (INIS)

    X-ray diffraction and electrophysical investigations into lithium triborate (LiB3O5) are presented. Specification of the atomic model is performed using the least square method in the full-matrix variant with regard to the atom thermal oscillation anisotropy in harmonic approximation. The results of investigations conducted allow one to conclude that conductivity in LiB3O5 is conditioned by Li+ ion mobility

  19. LiCl(NaCl)-CeCl3-H2O systems at 25 deg C

    International Nuclear Information System (INIS)

    It has been found by the method of isothermal solubility that aqueous ternary systems LiCl(NaCl)-CeCl3-H2O at 25 deg C refer to the eutonic type with crystallization of the initial components LiClxH2O, NaCl, and CeCl3x7H2O

  20. Competition between Alkalide Characteristics and Nonlinear Optical Properties in OLi3-M-Li3O (M=Li, Na and K) Complexes

    CERN Document Server

    Srivastava, Ambrish Kumar

    2016-01-01

    Alkalides possess enhanced nonlinear optical (NLO) responses due to localization of excess electrons on alkali metals. We have proposed a new class of alkalides by sandwiching alkali atoms (M) between two Li3O superalkali clusters at MP2/6-311++G(d,p) level. We notice a competition between alkalide characteristics and NLO properties in OLi3-M-Li3O (M=Li, Na and K) isomers. For instance, the atomic charge on M (qM) in D2h structure is -0.58e for M=Li and its first static mean hyperpolarizablity (\\b{eta}o) is 1 a.u., but in C2v structure, qM=-0.12e and \\b{eta}o= 3.4*103 a.u. More interestingly, the \\b{eta}o value for M=K (C2v) increases to 1.9*104 a.u. in which qM=0.24e. These findings may provide new insights into the design of alkalides, an unusual class of salts and consequently, lead to further researches in this direction.

  1. Investigation of energy stability, geometric structure, force fields, and vibrational spectra of LiNaF2, LiMgF3, and LiAlF4 molecules by means of MO LCAO SCF method

    International Nuclear Information System (INIS)

    By the MO LCAO SCF method with Huzinaga-Dumming and McLean-Chandler two-exponent basis sets, supplemented by d-functions on the Period III atoms, ab initio calculations have been performed for the equilibrium geometric parameters, coefficients of the quadratic force field, vibrational frequencies and intensities in the IR spectra, dipole moments, ionization potentials (according to the Koopmans theorem), Mulliken populations, and enthalpy and entropy of complexation of the molecules LiNaF2, LiMgF3, and LiAlF4. A study has been made of the effects on the calculated results when the basis is extended by inclusion of polarization and diffuse functions on the fluorine atoms. The calculated characteristics are compared with the available experimental data. A reassignment has been performed for certain frequencies in the IR spectrum of LiNaF2, as assigned previously by S.J. Syvin, B.N. Syvin, and A Snelson, J. Phys. Chem., 74, No. 25, 4338 (1970). Certain frequencies of low-intensity vibrations have been predicted in the IR spectra, frequencies not yet found experimentally

  2. Synthèse et étude structrale de lyonsite-type (Na0,4,Li0,6(Fe,Li2(MoO43

    Directory of Open Access Journals (Sweden)

    Amira Souilem

    2015-06-01

    Full Text Available The new compound (Na0.4,Li0.6(Fe,Li2(MoO43 was synthesized by cooling from the melt. Its anionic framework is built up from two distinct MO6 octahedra, each containing disordered Li+ and Fe3+ ions in 0.6:0.4 and 0.7:0.3 ratios, and two MoO4 tetrahedra, which link by vertex-sharing of their O atoms. These tetrameric units are further linked by sharing edges between octahedra and by formation of M—O—Mo (M = Fe/Li bridges, forming ribbons propagating in the [100] direction. The ribbons are cross-linked in both the b- and c-axis directions, giving rise to a three-dimensional framework having [100] tunnels in which the monovalent Na+/Li+ cations (0.4:0.6 ratio lie. Bond-valence calculations are consistent with the disorder model for the cations. The structure of the title compound, which is isotypic with Li3Fe(MoO43 and Li3Ga(MoO43, is compared briefly with those of LiFeMo2O8 and Li1.6Mn2.2(MoO43.

  3. Synthèse et étude structrale de lyonsite-type (Na0,4,Li0,6)(Fe,Li2)(MoO4)3.

    Science.gov (United States)

    Souilem, Amira; Zid, Mohamed Faouzi; Driss, Ahmed

    2015-06-01

    The new compound (Na0.4,Li0.6)(Fe,Li2)(MoO4)3 was synthesized by cooling from the melt. Its anionic framework is built up from two distinct MO6 octa-hedra, each containing disordered Li(+) and Fe(3+) ions in 0.6:0.4 and 0.7:0.3 ratios, and two MoO4 tetra-hedra, which link by vertex-sharing of their O atoms. These tetra-meric units are further linked by sharing edges between octa-hedra and by formation of M-O-Mo (M = Fe/Li) bridges, forming ribbons propagating in the [100] direction. The ribbons are cross-linked in both the b- and c-axis directions, giving rise to a three-dimensional framework having [100] tunnels in which the monovalent Na(+)/Li(+) cations (0.4:0.6 ratio) lie. Bond-valence calculations are consistent with the disorder model for the cations. The structure of the title compound, which is isotypic with Li3Fe(MoO4)3 and Li3Ga(MoO4)3, is compared briefly with those of LiFeMo2O8 and Li1.6Mn2.2(MoO4)3. PMID:26090130

  4. Synthesis and crystal structure of alkali metal uranium sulfides, Li2US3 and Na2US3

    International Nuclear Information System (INIS)

    New mixed uranium sulfides, A2US3 (A=Li,Na), in which uranium is in a tetravalent state, have been synthesized. In the disordered state, the compounds are written as A(A1/3,U2/3)S2 which have a hexagonal (R anti 3m) structure the same as the lanthanide homologue, ALnS2 (Ln=trivalent lanthanides). In the ordered state, the compounds take on a monoclinic (C2/m) structure in which the atom arrangement is very close to the above hexagonal structure. The partial ordering is realized by the coexistence of the two phases. The lattice parameters of hexagonal Li2US3 are a=3.898 and c=18.391 A, while those of monoclinic Li2US3 are a=6.747, b=11.679, c=6.537 A and β=110.2 . The lattice parameters of hexagonal Na2US3 are a=4.036 and c=19.780 A. Those of monoclinic Na2US3 are a=6.990, b=12.105, c=6.992 A and β=109.5 . The molar ratios of the hexagonal and monoclinic phases are 52.2:47.8 for Li2US3 and 68.0:32.0 for Na2US3, respectively. The atom parameters of uranium and sulfur were obtained by Rietveld calculation of the observed X-ray peaks. The atom separations are discussed in relation to the crystal radii of the component ions. (orig.)

  5. Thermoluminescent characteristics of newly developed LiF:Mg,Cu,Na,Si TL detectors

    International Nuclear Information System (INIS)

    Recently, a new sintered pellet-type LiF:Mg,Cu,Na,Si TL detector which has a high sensitivity and good reusability, named KLT-300(KAERI LiF:Mg,Cu,Na,Si TL detector), was developed by the variation of the dopants concentrations and the parameters of the preparation procedure at KAERI(Korea Atomic Energy Research Institute). In this study, the thermoluminescent characteristics of the newly developed TL detectors were investigated. The sensitivity of the TL detector was compared with that of the TLD-100 by light integration. The dose linearity of the detector was tested from 10-6 Gy up to 30 Gy. The dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 keV to 662 keV. The result shows that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively was 0.0054. Lower limit of detection for the detector was investigated at 70 nGy by the Harshaw 4500 TLD reader and the residual signal of the TL detector was found to be 0.57%

  6. Understanding charge transfer of Li+ and Na+ ions scattered from metal surfaces with high work function

    Science.gov (United States)

    Chen, Lin; Wu, Wen-Bin; Liu, Pin-Yang; Xiao, Yun-Qing; Li, Guo-Peng; Liu, Yi-Ran; Jiang, Hao-Yu; Guo, Yan-Ling; Chen, Xi-Meng

    2016-08-01

    For Li+ and Na+ ions scattered from high work function metal surfaces, efficient neutralization is observed, and it cannot be explained by the conventional free electron model. In order to explain these experimental data, we investigate the velocity-dependent neutral fraction with the modified Brako–Newns (BN) model. The calculated results are in agreement with the experimental data. We find that the parallel velocity effect plays an important role in neutralizing the Li+ and Na+ ions for large angle scattering. The nonmonotonic velocity behavior of neutral fraction is strongly related to the distance-dependent coupling strength between the atomic level and metal states. Project supported by the National Natural Science Foundation of China (Grant Nos. 11405078 and 11474140), the Fundamental Research Funds for the Central Universities, China (Grant Nos. lzujbky-2014-169 and lzujbky-2015-244), the Project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, the State Education Ministry, and the National Students’ Innovation and Entrepreneurship Training Program (Grant Nos. 201410730069 and 201510730078).

  7. Thermoluminescence properties of LiF:Mg,Cu,Na,Si pellets in radiation dosimetry

    International Nuclear Information System (INIS)

    Sintered LiF:Mg,Cu,Na,Si thermoluminescence (TL) pellets have been developed for application in radiation dosimetry. LiF:Mg,Cu,Na,Si pellets were made from TL powders using a sintering process, that is, pressing and heat treatment. These pellets have a diameter of 4.5 mm, and a thickness of 0.8 mm are blue in colour and have a mass of 28 mg each. After 400 pellets have been produced they were irradiated with 137Cs gamma radiation and samples having a sensitivity within a ±5% standard deviation were selected for experimental use. In the present study, the physical and dosimetric properties of LiF:Mg,Cu,Na,Si TL pellets were investigated for their emission spectrum, dose response, energy response and fading characteristics. Photon irradiation for the experiments was carried out using X ray beams and a 137Cs gamma source at the Korea Atomic Energy Research Institute. The average energies and the dose were in the range of 20-662 keV and 10-6-102 Gy respectively. The glow curves were measured with a manual type thermoluminescence dosimetry reader (system 310, Teledyne) at a constant nitrogen flux and a linear heating rate. For a constant heating rate of 5 deg. C.s-1, the main dosimetric peak of the glow curve appeared at 234 deg. C, its activation energy was 2.34 eV and the frequency factor was 1.00x1023. The TL emission spectrum appeared at the blue region centred at 410 nm. A linearity of photon dose response was maintained up to 100 Gy. The photon energy responses relative to the 137Cs response were within ±20% in the overall photon energy region. No fading of the TL sensitivity of the pellets stored at room temperature was found over the course of a year. Therefore LiF:Mg,Cu,Na,Si TL pellets can be used for personal dosimetry, but more research is needed to improve the characteristics for repeated use. (author)

  8. Energetics of a Li Atom adsorbed on B/N doped graphene with monovacancy

    Science.gov (United States)

    Rani, Babita; Jindal, V. K.; Dharamvir, Keya

    2016-08-01

    We use density functional theory (DFT) to study the adsorption properties and diffusion of Li atom across B/N-pyridinic graphene. Regardless of the dopant type, B atoms of B-pyridinic graphene lose electron density. On the other hand, N atoms (p-type dopants) have tendency to gain electron density in N-pyridinic graphene. Higher chemical reactivity and electronic conductivity of B/N-pyridinic graphene are responsible for stronger binding of Li with the substrates as compared to pristine graphene. The binding energy of Li with B/N-pyridinic graphene exceeds the cohesive energy of bulk Li, making it energetically unfavourable for Li to form clusters on these substrates. Li atom gets better adsorbed on N-pyridinic graphene due to an additional p-p hybridization of the orbitals while Li on B-pyridinic prefers the ionic bonding. Also, significant distortion of N-pyridinic graphene upon Li adsorption is a consequence of the change in bonding mechanism between Li atom and the substrate. Our results show that bonding character and hence binding energies between Li and graphene can be tuned with the help of B/N doping of monovacancy defects. Further, the sites for most stable adsorption are different for the two types of doped and defective graphene, leading to greater Li uptake capacity of B-pyridinic graphene near the defect. In addition, B-pyridinic graphene offering lower diffusion barrier, ensures better Li kinetics. Thus, B-pyridinic graphene presents itself as a better anode material for LIBs as compared to N-pyridinic graphene.

  9. Adsorption of Na, Mg, and Al atoms on BN nanotubes

    International Nuclear Information System (INIS)

    Adsorption of three metals (Na, Mg, and Al) on the surface of BN nanotubes (BNNT) has been investigated by using density functional theory. Adsorption energies for Na and Al atoms have been calculated to be about − 0.22 to − 0.61 eV, respectively. Upon the metal adsorption, energy gap between highest occupied and lowest unoccupied orbitals of the tube is dramatically decreased, resulting in enhanced electrical conductivity. However, in the case of Mg atom, the low adsorption energy cannot change electronic property of the tube. The semi-conductive BNNT transform to n-type semiconductor after adsorption of Na atom. The metal adsorption modifies work function of the BNNT and consequently the field-emission current densities of metal-BNNT may be significantly enhanced. - Highlights: ► Adsorption of Na, Mg, and Al atoms on the BN nanotubes (BNNT) was studied. ► Adsorption energies for Na and Al atoms are about − 0.22 to − 0.61 eV, respectively. ► Energy gap of the tube dramatically decreases upon the metals adsorption. ► Semiconductor BNNT transform to n-type ones upon adsorption of Na and Al atoms. ► The field-emission current densities of metal-BNNT may be significantly enhanced.

  10. Adsorption of Na, Mg, and Al atoms on BN nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Beheshtian, Javad [Department of Chemistry, Shahid Rajaee Teacher Training University, P.O. Box: 16875-163, Tehran (Iran, Islamic Republic of); Peyghan, Ali Ahmadi, E-mail: ahmadi.iau@gmail.com [Young Researchers Club, Islamic Azad University, Islamshahr Branch, Tehran (Iran, Islamic Republic of); Bagheri, Zargham [Physics group, Science department, Islamic Azad University, Islamshahr Branch, P.O. Box: 33135-369, Islamshahr, Tehran (Iran, Islamic Republic of)

    2012-12-30

    Adsorption of three metals (Na, Mg, and Al) on the surface of BN nanotubes (BNNT) has been investigated by using density functional theory. Adsorption energies for Na and Al atoms have been calculated to be about - 0.22 to - 0.61 eV, respectively. Upon the metal adsorption, energy gap between highest occupied and lowest unoccupied orbitals of the tube is dramatically decreased, resulting in enhanced electrical conductivity. However, in the case of Mg atom, the low adsorption energy cannot change electronic property of the tube. The semi-conductive BNNT transform to n-type semiconductor after adsorption of Na atom. The metal adsorption modifies work function of the BNNT and consequently the field-emission current densities of metal-BNNT may be significantly enhanced. - Highlights: Black-Right-Pointing-Pointer Adsorption of Na, Mg, and Al atoms on the BN nanotubes (BNNT) was studied. Black-Right-Pointing-Pointer Adsorption energies for Na and Al atoms are about - 0.22 to - 0.61 eV, respectively. Black-Right-Pointing-Pointer Energy gap of the tube dramatically decreases upon the metals adsorption. Black-Right-Pointing-Pointer Semiconductor BNNT transform to n-type ones upon adsorption of Na and Al atoms. Black-Right-Pointing-Pointer The field-emission current densities of metal-BNNT may be significantly enhanced.

  11. Some properties of atomic beam produced by laser induced ablation of Li target

    International Nuclear Information System (INIS)

    Pulsed atomic beams produced in vacuum by laser induced ablation from a lithium target are analyzed by laser induced fluorescence (LIF). The 1-mixing processes induced in the n = 9, 10 Li Rydberg states by collisions with CO2 molecules illustrate the application of the method. Resolution is limited by the 1 mm diameter of the probe laser beam. Combining LIF and absorption measurements gives nLi as a function of time at various distances from the target surface. The investigation of the Li-C02 1-mixing process in a heat pipe oven proved impossible due to the high reactivity of Li with C02. This problem was solved by renewing the Li atoms at each laser shot. Values obtained for n = 9, n = 10 are k = 17 x 10-8 and 15 x 10-8 cc/sec, respectively

  12. Molecular dynamics simulations of LiCl association and NaCl association in water by means of ABEEM/MM

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Constrained molecular dynamics simulations have been used to investigate the LiCl and NaCl ionic association in water in terms of atom-bond electronegativity equalization method fused into molecular mechanics (ABEEM/MM). The simulations make use of the seven-site fluctuating charge and flexible ABEEM-7P water model, based on which an ion-water interaction potential has been constructed. The mean force and the potential of mean force for LiCl and NaCl in water, the charge distributions, as well as the structural and dynamical properties of contact ion pair dissociation have been investigated. The results are reasonable and informative. For LiCl ion pair in water, the solvent-separated ion pair configurations are more stable than contact ion pair configurations. The calculated PMF for NaCl in water indicates that contact ion pair and solvent-separated ion pair configurations are of comparable stability.

  13. Theoretical prediction of the fundamental properties for the ternary Li2PtH6 and Na2PtH6

    International Nuclear Information System (INIS)

    Li2PtH6 and Na2PtH6 are good candidate for hydrogen storage. The structural, elastic, electronic and optical properties of Li2PtH6 and Na2PtH6 compounds have been investigated using pseudo-potential plane–wave method based on the density functional theory. Computed lattice constant and H atom positional parameter at equilibrium agree well with the available experimental data. A quadratic pressure dependence of the elastic stiffness is found. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature are numerically estimated in the framework of the Voigt–Reuss–Hill approximation for Li2PtH6 and Na2PtH6 polycrystalline aggregate. The analyses of the band structure indicates that Li2PtH6 and Na2PtH6 are indirect gap semiconductors. The static dielectric constant and static refractive index are inversely proportional to the fundamental gap. Highlights: ► We predict elastic moduli, energy gaps and optical parameters. ► Electron effective mass is anisotropic. ► Li2PtH6 and Na2PtH6 are indirect gap semiconductors. ► The contribution to the optical spectra from main transitions are predicted.

  14. Synchrotron-Radiation X-Ray Investigation of Li+/Na+ Intercalation into Prussian Blue Analogues

    Directory of Open Access Journals (Sweden)

    Yutaka Moritomo

    2013-01-01

    Full Text Available Prussian blue analogies (PBAs are promising cathode materials for lithium ion (LIB and sodium ion (SIB secondary batteries, reflecting their covalent and nanoporous host structure. With use of synchrotron-radiation (SR X-ray source, we investigated the structural and electronic responses of the host framework of PBAs against Li+ and Na+ intercalation by means of the X-ray powder diffraction (XRD and X-ray absorption spectroscopy (XAS. The structural investigation reveals a robust nature of the host framework against Li+ and Na+ intercalation, which is advantageous for the stability and lifetime of the batteries. The spectroscopic investigation identifies the redox processes in respective plateaus in the discharge curves. We further compare these characteristics with those of the conventional cathode materials, such as, LiCoO2, LiFePO4, and LiMn2O4.

  15. Dosimetric properties of sintered LiF : Mg,Cu,Na,Si TL detectors

    International Nuclear Information System (INIS)

    Selected dosimetric properties of sintered LiF : Mg,Cu,Na,Si detectors were studied. Solid LiF : Mg,Cu,Na,Si pellets of diameters 4.5 mm and thickness 0.9 mm, dark blue in colour, were obtained by cold pressing and sintering the powder at 820 deg. C. The dosimetric properties of the newly developed detectors were studied and compared with the properties of LiF : Mg,Cu,P pellets (MCP-N). The annealing conditions were the same as those used for MCP-N detectors. X-ray exposures were performed at the KAERI,Taejon,Korea, while other irradiation and readout were carried out at the INP in Krakow, Poland. The glow-curve structure of LiF : Mg,Cu,Na,Si pellets is found to be comparable to that of MCP-N (LiF : Mg,Cu,P) detectors but the absolute sensitivity is about 50% lower. The photon energy response after doses of X-rays of energy about 100 keV shows a decrease, similar to that in LiF : Mg,Cu,P. For lower energies the response is higher than that for LiF : Mg,Cu,P due to the presence of high-Z elements (Na,Cu, and Si). The relative TL efficiency after doses of alpha particles from an 214 Am source of the sintered LiF : Mg,Cu,Na,Si detectors is similar to that of MCP-N (LiF : Mg,Cu,P)

  16. Systems Li, Na parallel F, CrO4 and Li, Cs parallel F, CrO4

    International Nuclear Information System (INIS)

    Ternary mutual systems of lithium and sodium chromates and fluorides, of lithium and cesium fluorides and chromates are studied. It is shown that not reaction heat effect (in Li, Cs parallel F, CrO4 it is higher than in Li, Na parallel F, CrO4 system, and the shift is more in the latter), but the salt solubility and melting point are decisive for equilibrium shift in ternary reciprocal systems. This statement is confirmed on the example of lithium and potassium chromate and halide (F-,Cl-, Br-, I-) reciprocal systems

  17. SOME PROPERTIES OF ATOMIC BEAM PRODUCED BY LASER INDUCED ABLATION OF Li TARGET

    OpenAIRE

    Harnafi, M.; Dubreuil, B.

    1987-01-01

    In this experiment, pulsed atomic beams produced in vacuum by laser induced ablation from lithium target are analyzed by laser-induced fluorescsence (LIF). As an application of this atomic beam production technique, the l-mixing processes induced in the n = 9, 10 Li Rydberg states by collisions with CO2 molecules have been investigated.

  18. Associative ionization of two laser excited Na atoms

    International Nuclear Information System (INIS)

    An investigation into the associative ionization of two sodium atoms excited by polarized laser beams is described. It was possible to excite the Na atoms in a velocity-selective way by exploiting the Doppler effect. The excitation of Na to the 32P3/2, F=3 level is discussed on the basis of so-called saturation curves. Experiments with seven different combinations of polarization of the two exciting laser beams are described and the results discussed. 86 refs.; 53 figs.; 6 tabs

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

    Science.gov (United States)

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

    2016-01-01

    Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1–10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential. PMID:27159324

  20. New-concept Batteries Based on Aqueous Li+/Na+ Mixed-ion Electrolytes

    OpenAIRE

    Liang Chen; Qingwen Gu; Xufeng Zhou; Saixi Lee; Yonggao Xia; Zhaoping Liu

    2013-01-01

    Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li+/Na+ mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. On...

  1. Synthèse et étude structrale de lyonsite-type (Na0,4,Li0,6)(Fe,Li2)(MoO4)3

    OpenAIRE

    Amira Souilem; Mohamed Faouzi Zid; Ahmed Driss

    2015-01-01

    The new compound (Na0.4,Li0.6)(Fe,Li2)(MoO4)3 was synthesized by cooling from the melt. Its anionic framework is built up from two distinct MO6 octa­hedra, each containing disordered Li+ and Fe3+ ions in 0.6:0.4 and 0.7:0.3 ratios, and two MoO4 tetra­hedra, which link by vertex-sharing of their O atoms. These tetra­meric units are further linked by sharing edges between octa­hedra and by formation of M—O—Mo (M = Fe/Li) bridges, forming ribbons propagating in the [100] direction. The ribbons a...

  2. Dependence of thermoluminescence in LiF:Mg,Cu,Na,Si phosphor on Na dopant concentration and thermal treatment

    International Nuclear Information System (INIS)

    A new phosphor, LiF:Mg,Cu,Na,Si, has been developed in this laboratory for thermoluminescence. The thermoluminescence dependence on the concentration of Na dopant between 0 mol% and 0.45 mol% and thermal treatment between 240 deg. C and 310 deg. C was investigated. With an increase of Na concentration, the TL sensitivity and the main peak increase when the annealing temperature is less than 300 deg. C. With an increase of annealing temperature, the position of the main glow peak shifts markedly towards higher temperatures, irrespective of Na concentrations. The height of the main peak depends strongly on the annealing temperature. TL sensitivity remains stable at annealing temperatures from 260 deg. C to 300 deg. C for 0 mol% Na concentration, from 250 deg. C to 300 deg. C for 0.05 mol% N concentration, from 260 deg. C to 290 deg. C for 0.1 mol% Na concentration, from 260 deg. C to 280 deg. C for 0.2 mol% Na concentration, from 250 deg.C to 270 deg. C for 0.35 mol% Na concentration, or from 260 deg. C to 280 deg. C for 0.45 mol% Na concentration. The ratio of the intensity annealed at 310 deg. C to the intensity annealed at 260 deg. C seems to be reduced with an increase of Na concentration. Thermal susceptibility of LiF:Mg,Cu,Na,Si appears to be associated with the Na concentration. The lower the Na concentration, the less sensitive the TL is to annealing temperature. The optimum Na dopant concentration was found to be 0%

  3. Electronic excitation of Na atom by electron impact

    International Nuclear Information System (INIS)

    Electronic excitation of the 3s-3p transition in the Na atom was studied by intermediate energy electron impact spectroscopy. Differential Cross Sections (DCS) and Generalized Oscillator Strenghts (GOS) were determined experimentally for 1 KeV electrons. Theoretical results within the First Born Approximation as well as Glauber theory, were also performed. (A.C.A.S.)

  4. Luminescence characteristics of Eu and Ti doped LiNaF2 phosphor

    Science.gov (United States)

    Puppalwar, S. P.; Dhoble, S. J.; Lochab, S. P.; Kumar, A.

    2012-08-01

    Polycrystalline low Z phosphors (Zeff = 9.54) LiNaF2:Eu and LiNaF2:Ti prepared by standard solid state diffusion method are studied for their photoluminescence (PL) and thermoluminescence (TL) characteristics. The PL emission spectra of the phosphors suggest the presence of Eu3+ and Ti4+ in the host compound occupying two different lattice sites. The intense emission observed in the spectrum of Eu doped phosphor is assigned to electronic transitions 5D0 →7F2 in Eu3+ ions. In Ti4+ doped phosphor the observed emission in the range 350-390 nm attributed to Ti4+ ions. The TL glow curves of these LiNaF2 phosphors exposed to γ-rays from 137Cs for different exposures are discussed for the first time. The thermoluminescence (TL) response in the 0.1-5.3 Gy dose range increased linearly with the increase in radiation dose. The whole glow curve displays a remarkable stability upon storage at room temperature. The TL sensitivity of the phosphors is compared with standard commercial TLD phosphor CaSO4:Dy and is found to be 5.37 times less in LiNaF2:Eu and 9.25 times less in LiNaF2:Ti phosphor.

  5. Plasmon response in K, Na and Li clusters: systematics using the separable random-phase approximation with pseudo-Hamiltonians

    International Nuclear Information System (INIS)

    The systematics of the plasmon response in spherical K, Na and Li clusters in a wide size region (8≤N≤440) is studied. We have considered two simplifying approximations whose validity has been established previously. First, a separable approach to the random-phase approximation is used. This involves an expansion of the residual interaction into a sum of separable terms until convergence is reached. Second, the electron-ion interaction is modelled by using the pseudo-Hamiltonian jellium model (MHJM) which includes nonlocal effects by means of realistic atomic pseudo-Hamiltonians. In cases where nonlocal effects are negligible the Structure Averaged Jellium Model (SAJM) has been used. Good agreement with available experimental data is achieved for K, Na (using the SAJM) and small Li clusters (invoking the PHJM). The trends for peak position and width are generally well reproduced, even up to details of the Landau fragmentation in several clusters. Less good agreement, however, is found for large Li clusters. This remains an open question

  6. Circular magnetic dichroism of the Fa center adsorption in KCl doped with Li and Na

    International Nuclear Information System (INIS)

    The spin-orbit structure of FA in KCl:Li and KCl:Na have been studied by means of the magnetic circular dichroism. Due to their C4V, symmetry the FA centers have two different spin-orbit parameters, Δ* and Δ*, which only in the KCl:Li case follow the relation: Δ* F A centers have been determined using the method of moment

  7. First-principles study of diffusion of Li, Na, K and Ag in ZnO

    Science.gov (United States)

    Huang, Gui-Yang; Wang, Chong-Yu; Wang, Jian-Tao

    2009-08-01

    Based on ab initio total energy calculations, Li, Na and Ag interstitials are found to be stable with at least a 1.56 eV energy barrier to transform to a zinc substitutional site in ZnO, whereas K interstitial has a relatively small energy barrier at 0.79 eV. The isolated dopant substitutional defects (LiZn, NaZn, KZn and AgZn) are found to be rather stable, with at least a 3.4 eV energy barrier to transform to an interstitial site. All of the dopant interstitials (Lii, Nai, Ki and Agi) are fast diffusers. The diffusion of Li interstitial is isotropic, whereas the diffusion of Na, K and Ag interstitials is highly anisotropic. Fundamental processes of the vacancy-assisted mechanisms are systematically investigated and specific values of the energy barriers are obtained.

  8. Li2O(Na2O)-CoO-V2O5 systems

    International Nuclear Information System (INIS)

    Equilibrium phase composition of the systems: Li2O-CoO-V2O5 and Na2O-CoO-V2O5 at subsolidus temperatures has been studied. Formation of solid solution Li1-xCox/2VO3 (0≤ x ≤ 0.20) and binary orthovanadate LiCoVO4 in lithium-containing system is shown. No ternary compounds have been revealed in sodium-containing system. The relevant diagrams of phase ratios are plotted and their triangulation is performed. 18 refs

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

    Science.gov (United States)

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

    2015-06-10

    In the past decades, Li ion batteries are widely considered to be the most promising rechargeable batteries for the rapid development of mobile devices and electric vehicles. There arouses great interest in Na ion batteries, especially in the field of static grid storage due to their much lower production cost compared with Li ion batteries. However, the fundamental mechanism of Li and Na ion transport in nanoscale electrodes of batteries has been rarely experimentally explored. This insight can guide the development and optimization of high-performance electrode materials. In this work, single nanowire devices with multicontacts are designed to obtain detailed information during the electrochemical reactions. This unique platform is employed to in situ investigate and compare the transport properties of Li and Na ions at a single nanowire level. To give different confinement for ions and electrons during the electrochemical processes, two different configurations of nanowire electrode are proposed; one is to fully immerse the nanowire in the electrolyte, and the other is by using photoresist to cover the nanowire with only one end exposed. For both configurations, the conductivity of nanowire decreases after intercalation/deintercalation for both Li and Na ions, indicating that they share the similar electrochemical reaction mechanisms in layered electrodes. However, the conductivity degradation and structure destruction for Na ions is more severe than those of Li ions during the electrochemical processes, which mainly results from the much larger volume of Na ions and greater energy barrier encountered by the limited layered spaces. Moreover, the battery performances of coin cells are compared to further confirm this conclusion. The present work provides a unique platform for in situ electrochemical and electrical probing, which will push the fundamental and practical research of nanowire electrode materials for energy storage applications. PMID:25989463

  10. Thermodynamic assessment of the (LiF + UF3) and (NaF + UF3) systems

    International Nuclear Information System (INIS)

    Highlights: ► Thermodynamic description of the LiF–UF3 and NaF–UF3 liquid solutions. ► Experimental investigation of the (LiF + UF3) and (NaF + UF3) systems using differential scanning-calorimetry (DSC). ► Calculating the effect of increasing amounts of UF4 in the (LiF + UF3) and (NaF + UF3) systems. - Abstract: In this article new thermodynamic descriptions of the (LiF + UF3) and the (NaF + UF3) systems based on new calorimetric data are presented. The experimental investigations were carried out using differential scanning calorimetry (DSC) to obtain phase transition temperatures between (0 and 60) mol% of UF3. On the basis of these measurements a thermodynamic assessment of the (LixU1-x)F3-2x and (NaxU1-x)F3-2x liquid solutions, using the quasi-chemical model was achieved. UF3 undergoes a disproportionation at higher temperatures to UF4 and U metal which had a significant impact on the transition temperatures in the (LiF + UF3) system. For this reason the influence of the presence of up to 15 mol% of UF4 in this system was calculated and compared to the experimental results. The final thermodynamic description was corrected for the pure binary system.

  11. Valence photodetachment of Li- and Na- using relativistic many-body techniques

    International Nuclear Information System (INIS)

    The multiconfiguration Tamm-Dancoff technique (MCTD) is applied to study photodetachment of negative ions of lithium and sodium. A cusplike structure is found in the photodetachment cross section just below the first detachment-plus-excitation threshold of Li- (Li 2p), and of Na- (Na 3p), in qualitative agreement with existing theoretical and experimental results. The current work emphasizes the importance of correlation in the form of configuration interaction in the photodetachment process and demonstrates the utility of MCTD in dealing with highly correlated systems.

  12. Valence photodetachment of Li- and Na- using relativistic many-body techniques

    Science.gov (United States)

    Jose, J.; Pradhan, G. B.; Radojević, V.; Manson, S. T.; Deshmukh, P. C.

    2011-05-01

    The multiconfiguration Tamm-Dancoff technique (MCTD) is applied to study photodetachment of negative ions of lithium and sodium. A cusplike structure is found in the photodetachment cross section just below the first detachment-plus-excitation threshold of Li- (Li 2p), and of Na- (Na 3p), in qualitative agreement with existing theoretical and experimental results. The current work emphasizes the importance of correlation in the form of configuration interaction in the photodetachment process and demonstrates the utility of MCTD in dealing with highly correlated systems.

  13. Vrijeme latencije kao indikator iskrivljavanja odgovora na upitnicima ličnosti

    OpenAIRE

    Parmač, Maja; Galić, Zvonimir; Jerneić, Željko

    2009-01-01

    Cilj istraživanja bio je provjeriti model disimulacije na česticama upitnika ličnosti koji su postavili Holden, Kroner, Fakken i Popham (1992). Model objašnjava procese koji se nalaze u osnovi razlika u vremenima odgovaranja iskrenih ispitanika i ispitanika koji iskrivljavaju svoje odgovore. Temeljna je pretpostavka modela da ispitanici prilikom odgovaranja na upitnik ličnosti uspoređuju čestice upitnika s trenutnom kognitivnom shemom te da postoji interakcija te sheme i socijalne poželjnosti...

  14. Transmission channels through Na and Al atom wire

    DEFF Research Database (Denmark)

    Kobayashi, N.; Brandbyge, Mads; Tsukada, M.

    First-principles calculations of the transmission channels of single-atom-width Na and Al atom wires bridged between metallic jellium electrodes are presented. For the Na wire, a single channel contributes to the conduction with an almost full quantization value, 2e(2)/h. The conductance is...... insensitive to the geometrical change since the Fermi energy is located above the onset energy of the channel showing the quantization of conductance. On the other hand, for the Al wire. three channels contribute to the conduction. The Fermi energy is placed just at the onset of the second and the third...... channels, and the channel transmissions are very sensitive to the geometrical changes of the wires. (C) 1999 Elsevier Science B.V. All rights reserved....

  15. Dilithium disodium nickel(II cyclohexaphosphate dodecahydrate, Li2Na2NiP6O18·12H2O

    Directory of Open Access Journals (Sweden)

    Sonia Abid

    2012-08-01

    Full Text Available The crystal structure of Li2Na2NiP6O18·12H2O is characterized by the presence of six-membered P6O186− phosphate ring anions (internal symmetry -1 having a chair conformation and three different cations, viz. Li+, Na+ and Ni2+, to counterbalance the anionic charge. All atoms are in general positions except for nickel, which lies on a special position with site symmetry 2. Lithium has a tetrahedral environment (LiO4, and sodium and nickel have octahedral environments [NaO6 and Ni(H2O6, respectively]. The P6O18 rings are linked via corner sharing by NaO6 octahedra and LiO4 tetrahedra to form a three-dimensional framework presenting tunnels running along [010] in which the six-coordinated Ni2+ cations are located. The structure is stabilized by a network of O—H...O hydrogen bonds.

  16. A combined NaI(Tl)+LiI(Eu) detector for environmental, geological and security applications

    International Nuclear Information System (INIS)

    A device based on a combined NaI(Tl)+LiI(Eu) detection system for environmental monitoring, geological neutron logging, as well as security (explosives detection) applications is presented. It allows the user to simultaneously obtain both a gamma amplitude spectrum, as well as the time distribution of the moment of detection of thermal neutrons

  17. Density functional study of electronic structure, elastic and optical properties of MNH2 (M=Li, Na, K, Rb)

    International Nuclear Information System (INIS)

    We report a systematic first principles density functional study on the electronic structure, elastic and optical properties of nitrogen based solid hydrogen storage materials LiNH2, NaNH2, KNH2, and RbNH2. The ground state structural properties are calculated by using standard density functional theory, and also dispersion corrected density functional theory. We find that van der Waals interactions are dominant in LiNH2 whereas they are relatively weak in other alkali metal amides. The calculated elastic constants show that all the compounds are mechanically stable and LiNH2 is found to be a stiffer material among the alkali metal amides. The melting temperatures are calculated and follow the order RbNH2 2 2 2. The electronic band structure is calculated by using the Tran–Blaha modified Becke–Johnson potential and found that all the compounds are insulators, with a considerable band gap. The [NH2]− derived states completely dominate in the entire valence band region while the metal atom states occupy the conduction band. The calculated band structure is used to analyze the different interband optical transitions occurring between valence and conduction bands. Our calculations show that these materials have considerable optical anisotropy. (paper)

  18. Dynamic dipole polarizabilities of the Li atom and the Be+ ion

    International Nuclear Information System (INIS)

    The dynamic dipole polarizabilities for Li atoms and Be+ ions in the 2 2S and 2 2P states are calculated using the variational method with a Hylleraas basis. The present polarizabilities represent the definitive values in the nonrelativistic limit. Corrections due to relativistic effects are also estimated. Analytic representations of the polarizabilities for frequency ranges encompassing the n=3 excitations are presented. The recommended polarizabilities for 7Li and 9Be+ are 164.11±0.03 a03 and 24.489±0.004 a03, respectively.

  19. Glass transition temperature and conductivity in Li2O and Na2O doped borophosphate glasses

    Science.gov (United States)

    Ashwajeet, J. S.; Sankarappa, T.; Ramanna, R.; Sujatha, T.; Awasthi, A. M.

    2015-08-01

    Two alkali doped Borophosphate glasses in the composition, (B2O3)0.2. (P2O5)0.3. (Na2O)(0.5-x). (Li2O)x, where x = 0.05 to 0.50 were prepared by standard melt quenching method at 1200K. Non-crystalline nature was confirmed by XRD studies. Room temperature density was measured by Archimedes principle. DC conductivity in the temperature range from 300K to 575K has been measured. Samples were DSC studied in the temperature range from 423K to 673K and glass transition temperature was determined. Glass transition temperature passed through minima for Li2O con.2centration between 0.25 and 0.30 mole fractions. Activation energy of conduction has been determined by analyzing temperature variation of conductivity determining Arrhenius law. Conductivity passed through minimum and activation passed through maximum for Li2O content from 0.25 to 0.30 mole fractions. Glass transition temperature passed through minimum for the same range of Li2O content. These results revealed mixed alkali effect taking place in these glasses. It is for the first time borophosphate glasses doped with Li2O and Na2O have been studied for density and dc conductivity and, the mixed alkali effect (MAE) has been observed.

  20. Catalytic effect of fullerene and formation of nanocomposites with complex hydrides: NaAlH4 and LiAlH4

    International Nuclear Information System (INIS)

    Research highlights: → Catalytic effect of fullerenes on the reversible hydrogen storage → Hydrogen storage properties of alkali metal hydrides and fullerene mix forming nanocomposites → Novel ways of intercalating Na and Li atoms into C60 → Destabilization of hydrides → Potential to enable the formation of other high capacity hydrogen storage materials - Abstract: Carbonaceous nanomaterials utilized as scaffolds, catalysts, and additives in conjunction with complex metal hydrides have shown remarkable hydrogen sorption properties. Our studies have confirmed fullerene-C60 is an excellent catalyst for temperature induced hydrogen desorption for both NaAlH4 and LiAlH4. Fullerene-containing complex metal hydride composites comprised of fullerene-C60 with NaAlH4 or LiAlH4 desorbed hydrogen at elevated temperature and go onto form alkali metal fullerides and aluminum metal as final products. The as-prepared composites exhibit rapid hydrogen desorption at onset temperatures of 130 deg. C and 150 deg. C, and released hydrogen content of 5.9 and 2.2 wt.% (LiAlH4 and NaAlH4, respectively) relative to the composite. The resultant alkali metal fulleride containing composites have been characterized and are capable of reversible hydrogen storage. A series of desorption/absorption experiments on the Na-C60 and Li-C60 based composites demonstrate a 1.5 wt.% and a 1.2 wt.% reversible capacity, respectively. The complex metal hydride-C60 systems were characterized by PCT, XRD, FT-IR, and TGA-RGA and demonstrate the formation of fulleride material similar to traditional hydrofullerenes which appear to be responsible for the observed reversible hydrogen storage.

  1. Effect of divalent impurities on some physical properties of LiF and NaF

    International Nuclear Information System (INIS)

    The ionic thermo-currents technique is applied to the study of impurity vacancy dipoles in LiF and NaF doped with several divalent cations. In LiF only one ITC band is observed whatever the impurity studied. In NaF on the contrary two ITC bands are present, one corresponding to the one observed in LiF, the other one, intense in the case of small impurities, at lower temperature. A parallel EPR study in the case of Mn2+ doped samples shows that the band observed in LiF and the corresponding one in NaF are due to the relaxation of dipoles formed by the association of an impurity and a vacancy in the next nearest position. The knowledge of the properties of the dipoles allows to show that the room temperature ionic conductivity of LiF is conditioned by the equilibrium: M++ □+ → M++ + □+. It is also shown that the isolated cation vacancy originating from this dissociation is responsible for the enhancement of γ-ray coloration of LiF doped with divalent cation impurities. A paramagnetic center ascribed to the presence of Mn0 isolated in the lattice is also studied. The value of the hyperfine interaction and its temperature dependence are in good agreement with both the theory and the other experimental results. Finally it is shown that the disappearance of dipoles by annealing is related to the formation of complexes involving OH- ions, probably of the M(OH)2 type, with the two OH- ions occupying a single fluorine site. (author)

  2. Nuclear magnetic resonance study of sulfate reorientations in LiNaSO4

    International Nuclear Information System (INIS)

    A nuclear magnetic resonance study of the sulfate ion reorientations in β-LiNaSO4 has been carried out. The influence of the SO4 reorientational jumps on the quadrupolar interactions of 7Li nuclei was investigated by a jump reorientational model, which has not previously been applied to sulfates. The activation energy required for the SO4 reorientations was found to be 0.19 eV. It was also revealed that the SO4 reorientational disorder should be associated with a small anomaly of a heat capacity at around 600 K, which was previously observed experimentally. (paper)

  3. Nuclear magnetic resonance study of sulfate reorientations in LiNaSO4

    Science.gov (United States)

    Shakhovoy, R. A.; Rakhmatullin, A.; Deschamps, M.; Sarou-Kanian, V.; Bessada, C.

    2016-05-01

    A nuclear magnetic resonance study of the sulfate ion reorientations in β-LiNaSO4 has been carried out. The influence of the SO4 reorientational jumps on the quadrupolar interactions of 7Li nuclei was investigated by a jump reorientational model, which has not previously been applied to sulfates. The activation energy required for the SO4 reorientations was found to be 0.19 eV. It was also revealed that the SO4 reorientational disorder should be associated with a small anomaly of a heat capacity at around 600 K, which was previously observed experimentally.

  4. Study of the interface between Na-rich and Li-rich phases in a Na-inserted spinel Li4Ti5O12 crystal for an electrode of a sodium-ion battery.

    Science.gov (United States)

    Kitta, Mitsunori; Kataoka, Riki; Kohyama, Masanori

    2016-07-20

    Spinel lithium titanate (LTO; Li4Ti5O12) is one of the promising materials for negative electrodes of sodium-ion batteries (SIBs). The stable charge-discharge performance of SIB cells using LTO electrodes depends on the reversible Na insertion-extraction mechanism of LTO, where the spinel lattice is expanded with Na insertion, and two phases, Na-inserted LTO (Na-LTO) and Li-inserted LTO (Li-LTO) phases, are generated. These phases are confirmed using X-ray diffraction (XRD), while the mechanism of the two-phase coexistence with different lattice volumes is yet unclear. Here, we investigate the detailed morphology of the coexisting Na-LTO and Li-LTO phases using in situ XRD measurements and high-resolution transmission electron microscopy (TEM) observation. Na-LTO (a = 8.74 Å) and Li-LTO (a = 8.36 Å) phases are confirmed in both the electrochemically formed Na-inserted LTO electrode and the single-crystalline LTO thin specimen. We observed that the Na-LTO/Li-LTO interface is parallel to the (001) plane, and contains an inevitable lattice mismatch along the interface, while the expansion of the Na-LTO phase can be partially relaxed normal to the interface. We observed that the Na-LTO/Li-LTO interface has interface layers of lattice disordering with a 1-2 nm width, relaxing the lattice mismatch, as opposed to results from the previous scanning TEM observation. How the different lattice volumes at the two-phase interface are relaxed should be the key issue in investigation of the mechanism of Na insertion and extraction in LTO electrodes. PMID:27391208

  5. Band gap opening in silicene on MgBr2(0001) induced by Li and Na

    KAUST Repository

    Zhu, Jiajie

    2014-11-12

    Silicene consists of a monolayer of Si atoms in a buckled honeycomb structure and is expected to be well compatible with the current Si-based technology. However, the band gap is strongly influenced by the substrate. In this context, the structural and electronic properties of silicene on MgBr2(0001) modified by Li and Na are investigated by first-principles calculations. Charge transfer from silicene (substrate) to substrate (silicene) is found for substitutional doping (intercalation). As compared to a band gap of 0.01 eV on the pristine substrate, strongly enhanced band gaps of 0.65 eV (substitutional doping) and 0.24 eV (intercalation) are achieved. The band gap increases with the dopant concentration.

  6. Destabilized LiBH4-NaAlH4 Mixtures Doped with Titanium Based Catalysts

    DEFF Research Database (Denmark)

    Shi, Qing; Yu, Xuebin; Feidenhans'l, Robert;

    2008-01-01

    hydrogen release temperature compared to the undoped system and that of titanium doped LiAlH4 and NaAlH4 systems. Three dehydrogenation steps with a total of 3.5 wt% released hydrogen are observed for samples with a 2:3 molar ratio, when heated to similar to 210 degrees C under a constant heating ramp in a...... 1 bar helium atmosphere. A slow hydrogen release is also observed at room temperature in the freshly ball-milled powders due to decomposition of the formed LiAlH4. X-ray powder diffraction spectra shows that the first dehydrogenation step is completed after a couple of days at room temperature. Li...

  7. First-principles prediction of MgB2-like NaBC: A more promising high-temperature superconducting material than LiBC

    Science.gov (United States)

    Miao, Rende; Huang, Guiqin; Yang, Jun

    2016-05-01

    Crystal structure, lattice dynamics, and superconducting properties for sodium borocarbides NaB1+xC1-x are investigated with first-principles calculations. Based on crystal structure analysis by particle swarm optimization methodology, NaBC is predicted to crystallize in the layered P63 / mmc crystal structure as LiBC. However, it is different from LiBC, in that Na atoms are effectively ionized, with no longitudinal covalence exist between Na and B-C layers, just as in the case of MgB2. Therefore, Na1-xBC is more similar to MgB2 than Li1-xBC as a potential high-temperature superconductor. Further more, we suggest that the slight hole doping of NaBC through partial substitution of C by B atoms can also produce cause superconductivity. The phonon spectra for NaBC and NaB1.1C0.9 are obtained within the virtual-crystal approximation treatment. There is a remarkable softening of the in-plane B-C bond-stretching modes for NaB1.1C0.9 in certain regions of the Brillouin zone, while other phonon bands show no obvious softening behavior. This conspicuous softening of the in-plane B-C bond-stretching modes indicates a strong electron-phonon coupling for them. The obtained total electron-phonon coupling strength λ for NaB1.1C0.9 is 0.73, and superconducting transition temperature TC is predicted to be 35 K (μ* = 0.1). This indicates that NaB1+xC1-x is potentially high-temperature superconducting and hole doping of NaBC could produce high-temperature superconductivity. In addition, we conjecture that, to design a MgB2-like high TC superconducting material, the longitudinal covalent bonds between the metal cations and graphite-like layers need be excluded.

  8. Collision processes of Li3+ with atomic hydrogen: cross section database

    International Nuclear Information System (INIS)

    Using the available experimental and theoretical data, as well as established cross section scaling relationships, a cross section database for excitation, ionization and charge exchange in collisions of Li3+ ion with ground state and excited hydrogen atoms has been generated. The critically assessed cross sections are represented by analytic fit functions that have correct asymptotic behavior both at low and high collision energies. The derived cross sections are also presented in graphical form. (author)

  9. Organic anodes and sulfur/selenium cathodes for advanced Li and Na batteries

    Science.gov (United States)

    Luo, Chao

    To address energy crisis and environmental pollution induced by fossil fuels, there is an urgent demand to develop sustainable, renewable, environmental benign, low cost and high capacity energy storage devices to power electric vehicles and enhance clean energy approaches such as solar energy, wind energy and hydroenergy. However, the commercial Li-ion batteries cannot satisfy the critical requirements for next generation rechargeable batteries. The commercial electrode materials (graphite anode and LiCoO 2 cathode) are unsustainable, unrenewable and environmental harmful. Organic materials derived from biomasses are promising candidates for next generation rechargeable battery anodes due to their sustainability, renewability, environmental benignity and low cost. Driven by the high potential of organic materials for next generation batteries, I initiated a new research direction on exploring advanced organic compounds for Li-ion and Na-ion battery anodes. In my work, I employed croconic acid disodium salt and 2,5-Dihydroxy-1,4-benzoquinone disodium salt as models to investigate the effects of size and carbon coating on electrochemical performance for Li-ion and Na-ion batteries. The results demonstrate that the minimization of organic particle size into nano-scale and wrapping organic materials with graphene oxide can remarkably enhance the rate capability and cycling stability of organic anodes in both Li-ion and Na-ion batteries. To match with organic anodes, high capacity sulfur and selenium cathodes were also investigated. However, sulfur and selenium cathodes suffer from low electrical conductivity and shuttle reaction, which result in capacity fading and poor lifetime. To circumvent the drawbacks of sulfur and selenium, carbon matrixes such as mesoporous carbon, carbonized polyacrylonitrile and carbonized perylene-3, 4, 9, 10-tetracarboxylic dianhydride are employed to encapsulate sulfur, selenium and selenium sulfide. The resulting composites exhibit

  10. A study on tritium separation from LiPb by permeation into Na or NaK and cold trapping

    International Nuclear Information System (INIS)

    The tritium separation and recovery method discussed in this report appears to be a very promising technique for a LiPb self cooled blanket where an intermediate loop is required for safety reasons anyway. This technique can be also of interest for a water cooled LiPb blanket if a tritium purification unit exists in the water loop. Considerable work has been done on cold trapping of hydrogen from Na flows for the fast breeder technology. More work is needed in respect to fusion blanket applications, especially, on hydrogen removal from cold traps by thermal hydride decomposition. This report summarizes the state of the art on the precipitation and decomposition processes and discusses practical experiences with cold traps. Some ideas on a fusion blanket cold trap are outlined and a research program covering the more fundamental aspects for the next future is proposed. (orig.)

  11. Theoretical Study on Cyclopeptides as the Nanocarriers for Li+, Na+, K+ and F−, Cl−, Br−

    Directory of Open Access Journals (Sweden)

    Lili Liu

    2015-01-01

    Full Text Available The interaction process between a series of cyclopeptide compounds cyclo(Glyn  (n=4,6,8 and monovalent ions (Li+, Na+, K+, F−, Cl−, and Br− was studied using theoretical calculation. The mechanism of combination between the cyclo(Glyn and ions was discussed through binding energy, Mulliken electron population, and hydrogen bond. It was found that for the same cyclopeptide the binding energy has the order of cyclo(Glyn–Li+ > cyclo(Glyn–Na+ > cyclo(Glyn–K+ and cyclo(Glyn–F− > cyclo(Glyn–Br− > cyclo(Glyn–Cl−. The binding energy manifests the stable complex of cyclo(Glyn and ions can be formed, and the different energy shows the potential use of cyclo(Glyn as nanocarriers for metal ions or the extractant for ions separation.

  12. Crystal structure, spectroscopy and thermodynamic properties of MIVWO6(MI - Li, Na)

    International Nuclear Information System (INIS)

    In the present work lithium (sodium) vanadium tungsten oxides with brannerite structure is refined by the Rietveld method (space group C2/m, Z=2). IR and Raman spectroscopy was used to assign vibrational bands and determine structural particularities. The diffuse reflectance spectra allow to calculate bandgap for MIVWO6(MI - Li, Na). The temperature dependences of heat capacity have been measured first in the range from 7 to 350 K for these compounds and then between 330 and 640 K, respectively, by precision adiabatic vacuum and dynamic calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity Cpo(T), enthalpy Ho(T)-Ho(0), entropy So(T)-So(0) and Gibbs function Go(T)-Ho(0), for the range from T→0 to 640 K. The differential scanning calorimetry was applied to measure decomposition temperature of compounds under study. - Graphical abstract: Fragment of the structure of Li(Na)VWO6.

  13. Structural and optical properties of the M@C59X cages (X=N, B and M=Li, Na)

    Indian Academy of Sciences (India)

    Mojtaba Yaghobi; Alireza Adabinezhad

    2016-01-01

    Using B3LYP/6-31G* density functional level of theory, the structural and optical properties of the C60 and M@C59X cages have been investigated. Results indicate that the charge on C atoms and band gap of C60 cage are changed dramatically with the substitution of one B or N atom at one of the C sites and the Li and Na atom encapsulations in the C60 cage. The Mulliken analyses show that the charge is transferred completely between the alkali atoms and the C59X cage. The substitutional and encapsulation doping (SED) reduce the optical gaps of the C60 cage. Also, the oscillator strengths of the absorption peaks are dependent on dopant types.

  14. Magnetoplastic effect in irradiated NaCl and LiF crystals

    International Nuclear Information System (INIS)

    Impact of low doses of X-ray radiation on magnetoplastic effect is alkali-halide crystals, consisting in detachment of dislocations from paramagnetic centers under effect of external magnetic field is studied. The measurements of LiF crystals and three types of NaCl crystals, differing in the admixture content were conducted. Dependence of the dislocations medium run on the sample rotation frequency in the magnetic field proved to be especially sensitive to low doses

  15. Corrosion of Nickel Exposed to LiF-NaF Molten Salt

    Czech Academy of Sciences Publication Activity Database

    Král, Lubomír; Čermák, Jiří; Matal, O.; Šimo, T.; Nesvadba, L.

    Ostrava : TANGER, spol. s r.o., 2011, paper no. 882. ISBN 978-80-87294-22-2. [Anniversary International Conference on Metallurgy and Materials METAL 2011/20th./. Brno (CZ), 18.05.2011-20.05.2011] R&D Projects: GA MPO 2A-1TP1/067 Institutional research plan: CEZ:AV0Z20410507 Keywords : corrosion * molten salts * nickel * LiF–NaF Subject RIV: JG - Metallurgy

  16. Energy response and dose linearity of LiF:Mg, Cu, Na, Si TL detector

    International Nuclear Information System (INIS)

    The photon energy response of LiF : Mg, Cu, Na, Si thermoluminescence detector was measured using X-ray generator(20-118 keV) and 137Cs irradiator and its relative energy response appeared to be 0.825 for 20 keV photon normalized to that of 137Cs photon. The dose response was linear within the range of 10-4Gy - 20Gy, but shows sublinearity above 50Gy

  17. The Electrochemical Behaviour of Uranium in LiF-NaF Molten Salt

    Institute of Scientific and Technical Information of China (English)

    WANG; Chang-shui; LIU; Yi

    2012-01-01

    <正>The reduction mechanism in molten LiF-NaF eutectic containing UF4 was investigated by cyclic voltammetry and chronopotentiometry in 1 073 K. Two redox peaks have been observed in the cyclic voltammograms and two platforms have also occurred in the chronopotentiogram which indicates that the reduction process of U4+ consists of two steps. The number of electrons exchanged at each step has been

  18. Structure Refinement of Cs-rich Na-Li Beryl and Analysis of Its Typomorphic Characteristics of Configurations

    Institute of Scientific and Technical Information of China (English)

    LIU Yan; DENG Jun; LI Guowu; SHI Guanghai

    2007-01-01

    The tabular beryl found in Huya Country, Sichuan Province is a rare and special member among beryls. Chemical analysis reveals that the beryl is a new type of Cs-rich Na-Li beryl, and the content of alkalis (Li2O, Na2O, K2O, Rb2O, Cs2O) is up to 2.41%. The CCD system on the SMART APEX four circle single crystal diffractometer was used in this experiment to determine the structure of the sample accurately. The beryl belongs to the hexagonal system; its space group is P6/mcc. The dimensions of the unit cell are as follows: a = 0.91961(3) nm, c = 0.91969(7) nm, c/a= 1.0000, V= 0.67357nm3, γ = 120°, a = 90°, β = 90°. The accurate atomic coordinates of alkali metal ions and other crystallographic parameters are also obtained: Z = 2, the calculated density D = 2.754 g/cm3 and final R ( Ⅰ> 2 σ (Ⅰ))= 0.046 for 5597 reflections. The crystal structure was described by coordination polyhedron. Based on the data gained, a three-dimensional graph of the crystal structure of tabular beryl was made with the ATOMS 6.0 software. The refinement of crystal structure indicates that there are two main reasons for the cause of the tabular configuration: (1) The substitution of Be by Li into the tetrahedral framework weakened the stacked six-sided rings [Si6O1s]12- of the tetrahedral Si; (2) Alkalis (mainly Na and Cs) are too large to substitute in four-fold or six-fold coordination within the structure and are accommodated in the vacant channel. The accommodation of these alkalis strengthened the structure of six-sided rings of the tetrahedral Si. And other alkali metal ions and free volatile molecules such as H2O and CO2 occupy variable positions in the channel. The equation of the electrovalence is Li++Na+→Be2+. According to structural and compositional differences, the monoclinic crystal of tabular beryl is considered to be a new member of the beryl group. Chemical constraints of the environment, namely, the bulk-rock chemistry and the fluid-phase composition and

  19. Environmentally-friendly aqueous Li (or Na)-ion battery with fast electrode kinetics and super-long life

    OpenAIRE

    Dong, Xiaoli; Chen, Long; Liu, Jingyuan; Haller, Servane; Wang, Yonggang; Xia, Yongyao

    2016-01-01

    Current rechargeable batteries generally display limited cycle life and slow electrode kinetics and contain environmentally unfriendly components. Furthermore, their operation depends on the redox reactions of metal elements. We present an original battery system that depends on the redox of I−/I3 − couple in liquid cathode and the reversible enolization in polyimide anode, accompanied by Li+ (or Na+) diffusion between cathode and anode through a Li+/Na+ exchange polymer membrane. There are n...

  20. Thermodynamic investigation of the (LiF + NaF + CaF2 + LaF3) system

    International Nuclear Information System (INIS)

    Highlights: → Thermodynamic description of the liquid phases in the (LiF + NaF + CaF2 + LaF3) system. → DSC measurements for the systems (LiF + CaF2 + LaF3), (NaF + CaF2 + LaF3), and (LiF + NaF + CaF2 + LaF3). → Improved encapsulation technique for fluoride salts show better agreement to theory. → Similar extrapolation with quasi-chemical model and classical polynomial model. - Abstract: In this work a thermodynamic assessment of the (LiF + NaF + CaF2 + LaF3) system is reported. For the thermodynamic modeling of the liquid phase, the classical polynomial model, and the modified quasi-chemical model were used in parallel and compared. The extrapolation to higher order systems was done according to the Toop mathematical formalism. Furthermore, differential-scanning calorimetry data of the ternary (LiF + CaF2 + LaF3), (NaF + CaF2 + LaF3), and the quaternary (LiF + NaF + CaF2 + LaF3) mixtures are presented. Good agreement between the experimental data and the thermodynamic assessment was obtained.

  1. The crystal structure of synthetic simmonsite, Na2LiAlF6

    International Nuclear Information System (INIS)

    The structure of the synthetic fluoroperovskite, Na2LiAlF6 (simmonsite), has been determined by powder X-ray diffraction using the Rietveld method of structure refinement. The compound adopts space group P21/n [no. 14; a=5.2842(1); b=5.3698(1); c=7.5063(2) A; β=89.98(1) deg.; Z=4), and is a member of the cryolite (Na2NaAlF6) structural group characterized by ordering of the B-site cations (Li, Al) and tilting of the BF6 octahedra according to the tilt scheme a-b-c+. Rotations of the B-site polyhedra are less (PHILi=14.9 deg.; PHIAl=17.0 deg.) than those found in cryolite (PHINa=18.6; PHIAl=23.5 deg.) because of the larger difference in the ionic radii of the B-site cations in cryolite as compared to those in simmonsite. Na at the A-site is displaced from the special position resulting in 10- and 8-fold coordination in simmonsite and cryolite, respectively. By analogy with the synthetic compound, naturally occurring simmonsite is considered to adopt space group P21/n (no. 14) and not the P21(no. 4) or P21/m(no. 11) space groups

  2. The structures and vibrations of H2 monolayers on NaCl, MgO and LiF: similarities and differences

    International Nuclear Information System (INIS)

    A new low-temperature target manipulator (TS approx. = 7 K) has made it possible to extend diffractive and inelastic time-of-flight He atom scattering to the investigation of the structures and external vibrations of the monolayers H2/NaCl, H2/MgO and H2/LiF. On NaCl, H2 forms a (1 x 1) monolayer, whereas in the other systems a series of ordered increasingly compressed structures develops with increasing coverage. On MgO these structures are assigned to c(2 x 2), c(4 x 2) and c(6 x 2) phases. On LiF the most stable structure is, in analogy to H2/MgO, proposed to be close to c(8 x 2) with a 5% misfit with respect to the LiF substrate. For p-H2/NaCl, single and overtone vibrational excitations are observed up to the second overtone as well as combinations of a parallel nearly dispersionless mode, at 7.0 meV, and a new dispersive branch with 8.5 meV at the zone boundary. On MgO and LiF three collective vibrations are found. On MgO two non-dispersive perpendicularly polarized modes at 8.5 and 10.5 meV and a dispersive parallel mode at a lower energy are identified. On LiF only one non-dispersive mode at 10.5 meV and two dispersive unassigned modes at lower energies are found. The results for all three systems are compared, and they lead to some general conclusions about dynamical processes on cryogenic films of H2 on ionic crystals

  3. X-ray diffraction analysis of LiCu2O2 crystals with additives of silver atoms

    International Nuclear Information System (INIS)

    Silver-containing LiCu2O2 crystals up to 4 × 8 × 8 mm in size were grown by the crystallization of 80(1-x)CuO · 20xAgNO3 · 20Li2CO3 (0 ≤ x ≤ 0.5) mixture melt. According to the X-ray spectral and Rietveld X-ray diffraction data, the maximum amount of silver incorporated in the LiCu2O2 structure is about 4 at % relative to the copper content. It was established that silver atoms occupy statistically crystallographic positions of lithium atoms. The incorporation of silver atoms is accompanied by a noticeable increase in parameter c of the LiCu2O2 rhombic unit cell, a slight increase in parameter a, and a slight decrease in parameter b

  4. A further study of crystallization of lithium perchlorate from LiClO₄-NaCl-H₂O system

    Directory of Open Access Journals (Sweden)

    Goran Tadic

    2010-11-01

    Full Text Available The aim of this paper is to define feasible process pathways of fractional crystallization of NaCl and LiClO₄·3H₂0 from LiClO₄-NaCl-H₂O system using the information on the equilibrium of the LiClO₄-NaCl-H₂O system at different temperatures, as well as the information on the composition of the starting solution obtained by electrolysis and double exchange with LiCl. The paper also synthesizes a feasible process structure that can be applied for the process of fractional crystallization, and gives a simulation of the process by calculating the material balance of the process. The parameters of relevant process paths that were obtained prove that the process presented in this paper is feasible in practice and applicable in industry.

  5. Structure factors and phonon dispersion in liquid Li0.61Na0.39 alloy

    Indian Academy of Sciences (India)

    Arun Pratap; Kirit N Lad; K G Raval

    2004-08-01

    The phonon spectra for liquid Li and Na have been computed through the phenomenological model of Bhatia and Singh for disordered systems like liquids and glasses and the obtained results have been compared with the available data obtained by inelastic neutron scattering (INS) and inelastic X-ray scattering (IXS) experiments. The effective pair potentials and their space derivatives are important ingredients in the computation of the dispersion curves. The pair potentials are obtained using the pseudo-potential theory. The empty core model proposed by Ashcroft is widely used for pseudo-potential calculations for alkali metals. But, it is thought to be unsuitable for Li because of its simple 1s electronic structure. However, it can be used with an additional term known as Born–Mayer (BM) core term. The influence of the BM core term on the phonon dispersion is discussed. The same pseudo-potential formalism has been employed to obtain the dispersion relation in liquid Li0.61Na0.39 alloy. Apart from the phonon spectra, the Ashcroft–Langreth structure factors in the alloy are derived in the Percus–Yevick approximation.

  6. New development of highly sensitive sintered LiF;Mg,Cu,Na,Si TL detector

    International Nuclear Information System (INIS)

    A highly sensitive pellet-type LiF:Mg,Cu,Na,Si TL detector has been newly developed. The TL sensitivity of this new TL detector was about 30 times higher than that of the TLD-100 by light integration measurements. The optimum concentrations of dopants for a pellet-type LiF:Mg,Cu,Na,Si TL detector were investigated as Mg: 0.2 mol%, Cu: 0.05 mol%, Na: 0.9 mol% and Si: 0.9 mol%. The observed glow curve structure of the detector was suitable for practical TLD on the grounds of its significantly low level of ratio namely, height of the high temperature peak / height of the main dosimetric peak (P5/P4). Reusability study of the detector was carried out for 10 cycles of reuse. The results show that the coefficients of variation for each detector separately did not exceed 0.016, and for all 10 detectors collectively was 0.0054

  7. The role of residual Na + and Li + on the thermal transformation of Ba-exchanged zeolite A

    Science.gov (United States)

    Marocco, Antonello; Dell'Agli, Gianfranco; Esposito, Serena; Pansini, Michele

    2011-05-01

    This work intends to critically review the data concerning the variations of reactivity of Ba-exchanged zeolite A precursor with Na + and Li + content originally present in the zeolite framework. The main results were the following: a) obtaining a fully monoclinic celsian from Ba-exchanged zeolite A bearing Na + residual content ranging between 0.20 and 0.74 meq/g required a 5-22 h thermal treatment at 1300 °C; b) obtaining a fully monoclinic celsian from Ba-exchanged zeolite A bearing the not further reducible Na + residual content (about 0.20 meq/g) and Li + contents ranging from 0.11 to 0.37 meq/g required a 4-10 h thermal treatment at 1000-1100 °C. New insight into the mechanism through which Na + and Li + develop their mineralizing action on the thermal transformation of Ba-exchanged zeolite A was attained.

  8. Emergence of superconductivity in (NH3)yMxMoSe2 (M: Li, Na and K)

    Science.gov (United States)

    Miao, Xiao; Nishiyama, Saki; Zheng, Lu; Goto, Hidenori; Eguchi, Ritsuko; Ota, Hiromi; Kambe, Takashi; Terashima, Kensei; Yokoya, Takayoshi; Nguyen, Huyen T. L.; Kagayama, Tomoko; Hirao, Naohisa; Ohishi, Yasuo; Ishii, Hirofumi; Liao, Yen-Fa; Kubozono, Yoshihiro

    2016-01-01

    We report syntheses of new superconducting metal-doped MoSe2 materials (MxMoSe2). The superconducting MxMoSe2 samples were prepared using a liquid NH3 technique, and can be represented as ‘(NH3)yMxMoSe2’. The Tcs of these materials were approximately 5.0 K, independent of x and the specific metal atom. X-ray diffraction patterns of (NH3)yNaxMoSe2 were recorded using polycrystalline powders. An increase in lattice constant c showed that the Na atom was intercalated between MoSe2 layers. The x-independence of c was observed in (NH3)yNaxMoSe2, indicating the formation of a stoichiometric compound in the entire x range, which is consistent with the x-independence of Tc. A metallic edge of the Fermi level was observed in the photoemission spectrum at 30 K, demonstrating its metallic character in the normal state. Doping of MoSe2 with Li and K also yielded superconductivity. Thus, MoSe2 is a promising material for designing new superconductors, as are other transition metal dichalcogenides. PMID:27404919

  9. A semiclassical study of laser-induced atomic fluorescence from Na2, K2 and NaK

    Science.gov (United States)

    Yuan, J.-M.; Bhattacharyya, D. K.; George, T. F.

    1982-01-01

    A semiclassical treatment of laser-induced atomic fluorescence for the alkali-dimer systems Na2, K2 and NaK is presented. The variation of the fluorescence intensity with the frequency of the exciting laser photon is studied and a comparison of theoretical results with a set of experimental data is presented.

  10. Explicitly correlated wave functions for atoms and singly charged ions from Li through Sr: Variational and Diffusion Monte Carlo results

    Science.gov (United States)

    Buendía, E.; Gálvez, F. J.; Maldonado, P.; Sarsa, A.

    2014-11-01

    Total energies calculated from explicitly correlated wave functions for the ground state of the atoms Li to Sr and their singly charged anions and cations are obtained. Accurate all electron, non-relativistic Variational and Diffusion Monte Carlo energies are reported. The quality of the results, when comparing with exact estimations and experimental electron affinities and ionization potential is similar for all of the atoms studied. The parameterization of the explicitly correlated wave functions for all of the atomic systems studied is provided.

  11. Hyperspherical Calculations on Electron Affinity and Geometry for Li-and Na-

    Institute of Scientific and Technical Information of China (English)

    HAN Hui-Li; ZHANG Xian-zhou; SHI Ting-Yun

    2007-01-01

    Using a model potential to describe the interaction between the core and the valence electron,we perform hyperspherical calculations for electron affinity and geometry of the weakly bound Li-and Na-systems.In ourcalculation.channel functions are expanded in terms of B-splines.Using the special properties of B-splines,we make the knot distributions more precisely,characterizing the behaviour of channel functions.This improves the convergence greatly.Our results are in good agreement with the other theoretical and experimental values.

  12. Paramagnetic centres in X-irradiated LiNaSO4 single crystals

    International Nuclear Information System (INIS)

    The EPR and optical absorption spectra of paramagnetic centers produced by X-irradiation in LiNaSO4 single crystals were investigated. 7 EPR lines are observed at room temperature and 6 more lines at LNT. The angular dependences of line positions at LNT are studied and the principal g-factor values are defined. The comparison with published data permitted to assign six the most anisotropic lines to ion-radical SO4- with different orientations in the lattice; two lines to ion-radical SO2-; slightly anisotropic doublet line to O3- ozonide ion; isotropic line with g = 2.0045 to ion radical SO3-. (author)

  13. M@B40 (M = Li, Na, K) serving as a potential promising novel NLO nanomaterial

    Science.gov (United States)

    Shakerzadeh, Ehsan; Biglari, Zeinab; Tahmasebi, Elham

    2016-06-01

    Density functional theory (DFT) calculations have carried out to investigate the nonlinear optical response of the B40 fullerene by interaction with the alkali metals (Li, Na, K). The results reveal that the interacted fullerenes are energetically favorable. The B40 electronic properties are strongly sensitive to the interaction with the alkali metals. Furthermore, the adsorption of the alkali metals over the B40 hexagonal ring remarkably enhances the first hyperpolarizability up to 23111.72 a.u. Therefore, the B40 fullerene interacted with the alkali metals could be introduced as a promising innovative nonlinear optical boron-based nanomaterial.

  14. Electron spin resonance study of Na_{1-x}Li_xV_2O_5

    OpenAIRE

    Lohmann, M.; von Nidda, H. -A. Krug; Loidl, A.; Morre, E.; Dischner, M.; Geibel, C

    1999-01-01

    We measured X-band electron-spin resonance of single crystalline sodium vanadate doped with lithium, Na_{1-x}Li_xV_2O_5 for 0 < x < 1.3% . The phase transition into a dimerized phase that is observed at 34 K in the undoped compound, was found to be strongly suppressed upon doping with lithium. The spin susceptibility was analyzed to determine the transition temperature and the energy gap with respect to the lithium content. The transition temperature Tsp is suppressed following a square depen...

  15. Terahertz reflection spectroscopy of aqueous NaCl and LiCl solutions

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Merbold, Hannes

    2010-01-01

    We present spectroscopic measurements of the full dielectric function of aqueous solutions of sodium chloride and lithium chloride at concentrations approaching their solubility limits at room temperature. We find that the dielectric properties of the two salts are rather different at THz...... frequencies. Whereas both the real and imaginary part of the permittivity of NaCl increases with concentration,we see that the imaginary part of the permittivity of LiCl (related to the absorption)decreases with increasing salt concentration. We relate these changes to the behavior...

  16. Mg-8Li,Mg-8Li-0.5Ce和Mg-8Li-1Ce合金在0.7mol·L~(-1)NaCl溶液中电化学性能的研究%The Electrochemical Performances of Mg-8Li,Mg-8Li-0.5Ce and Mg-8Li-1Ce Alloys in 0.7 mol·L~(-1) NaCl Solution

    Institute of Scientific and Technical Information of China (English)

    吕艳卓; 徐岩; 王学新; 张毅; 陆天虹

    2011-01-01

    采用真空熔炼法制备了铸态Mg-8Li,Mg-8Li-0.5Ce和Mg-8Li-1Ce三种Mg-Li合金.采用Tafel极化曲线、恒电势氧化法和电化学阻抗谱法,研究了Mg,Mg-8Li,Mg-8Li-0.5Ce和Mg-8Li-1Ce电极作为Mg-H2O2半燃料电池的阳极材料在0.7 mol·L-1 NaCl溶液中的电化学行为.采用扫描电镜观测了电极放电前后的表面形貌.研究结果表明:在四种金属电极中,Mg-8Li-1Ce电极的腐蚀电位最正(-1.49 V),Mg电极的腐蚀电位最负(-1.66 V);在0.7 mol·L-1 NaCl溶液中,电极的电氧化活性排列顺序表示为:Mg-8Li〉Mg-8Li-1Ce〉Mg〉Mg-8Li-0.5Ce,在-1.0 V电位下,Mg-8Li电极的放电电流密度约为40 mA·cm-2.表明Mg-8Li电极的电氧化活性最好,Li元素对Mg电极起到了"活化"作用.%Mg-8Li,Mg-8Li-0.5Ce and Mg-8Li-1Ce alloys were prepared using vacuum induction melting method.The electrochemical performances of Mg,Mg-8Li,Mg-8Li-0.5Ce and Mg-8Li-1Ce electrodes as the anodes of Mg-H2O2 semi-fuel cells in 0.7 moloL-1 NaCl solution were investigated by means of poten-tiodynamic polarization,potentiostatic discharge and electrochemical impedance spectroscopy measure-ments.The surface morphology of the electrodes was observed by scanning electron microscopy.The results showed that the corrosion potential of Mg-8Li-1Ce(-1.49 V) is the most positive and the corrosion poten-tial of Mg(-1.66 V) is the most negative among the four electrodes.The electro-oxidation activity of the electrodes in 0.7 moloL-1 NaCl solution follows the sequence: Mg-8LiMg-8Li-1CeMgMg-8Li-0.5Ce.The current density of Mg-8Li electrode discharged at-1.0 V reached around 40 mAocm-2.The electro-oxidation activity of Mg-8Li is the highest among the four electrodes and the Li element "activated" Mg electrode.

  17. Automatic Tuning Matching Cycler (ATMC) in situ NMR spectroscopy as a novel approach for real-time investigations of Li- and Na-ion batteries

    Science.gov (United States)

    Pecher, Oliver; Bayley, Paul M.; Liu, Hao; Liu, Zigeng; Trease, Nicole M.; Grey, Clare P.

    2016-04-01

    We have developed and explored the use of a new Automatic Tuning Matching Cycler (ATMC) in situ NMR probe system to track the formation of intermediate phases and investigate electrolyte decomposition during electrochemical cycling of Li- and Na-ion batteries (LIBs and NIBs). The new approach addresses many of the issues arising during in situ NMR, e.g., significantly different shifts of the multi-component samples, changing sample conditions (such as the magnetic susceptibility and conductivity) during cycling, signal broadening due to paramagnetism as well as interferences between the NMR and external cycler circuit that might impair the experiments. We provide practical insight into how to conduct ATMC in situ NMR experiments and discuss applications of the methodology to LiFePO4 (LFP) and Na3V2(PO4)2F3 cathodes as well as Na metal anodes. Automatic frequency sweep 7Li in situ NMR reveals significant changes of the strongly paramagnetic broadened LFP line shape in agreement with the structural changes due to delithiation. Additionally, 31P in situ NMR shows a full separation of the electrolyte and cathode NMR signals and is a key feature for a deeper understanding of the processes occurring during charge/discharge on the local atomic scale of NMR. 31P in situ NMR with "on-the-fly" re-calibrated, varying carrier frequencies on Na3V2(PO4)2F3 as a cathode in a NIB enabled the detection of different P signals within a huge frequency range of 4000 ppm. The experiments show a significant shift and changes in the number as well as intensities of 31P signals during desodiation/sodiation of the cathode. The in situ experiments reveal changes of local P environments that in part have not been seen in ex situ NMR investigations. Furthermore, we applied ATMC 23Na in situ NMR on symmetrical Na-Na cells during galvanostatic plating. An automatic adjustment of the NMR carrier frequency during the in situ experiment ensured on-resonance conditions for the Na metal and

  18. Borophene as an extremely high capacity electrode material for Li-ion and Na-ion batteries.

    Science.gov (United States)

    Zhang, Xiaoming; Hu, Junping; Cheng, Yingchun; Yang, Hui Ying; Yao, Yugui; Yang, Shengyuan A

    2016-08-18

    "Two-dimensional (2D) materials as electrodes" is believed to be the trend for future Li-ion and Na-ion battery technologies. Here, by using first-principles methods, we predict that the recently reported borophene (2D boron sheets) can serve as an ideal electrode material with high electrochemical performance for both Li-ion and Na-ion batteries. The calculations are performed on two experimentally stable borophene structures, namely β12 and χ3 structures. The optimized Li and Na adsorption sites are identified, and the host materials are found to maintain good electric conductivity before and after adsorption. Besides advantages including small diffusion barriers and low average open-circuit voltages, most remarkably, the storage capacity can be as high as 1984 mA h g(-1) in β12 borophene and 1240 mA h g(-1) in χ3 borophene for both Li and Na, which are several times higher than the commercial graphite electrode and are the highest among all the 2D materials discovered to date. Our results highly support that borophenes can be appealing anode materials for both Li-ion and Na-ion batteries with extremely high power density. PMID:27502997

  19. The effect of Nb2O5 and ZrO2 additions on the behaviour of Li/MgO and Li/Na/MgO catalysts for the oxidative coupling of methane

    OpenAIRE

    McNamara, D J; Korf, S.J.; Seshan, K.; Ommen, van, B.; Ross, J.R.H.

    1991-01-01

    Incorporation of Nb2O5 or ZrO2 into both Li/MgO and Li/Na/MgO systems produced ternary and quaternary catalysts, respectively, capable of attaining optimal C2 yields and selectivities at lower temperatures relative to the unpromoted materials. The degree of enhancement effected by these metal oxide additives was compared to that produced by Li/MgO and Li/Na/MgO catalysts promoted with SnO2 or Co3O4. At reaction temperatures < 700°C, the Li/Co/MgO ternary system showed marked differences in be...

  20. Comparative study of LiF:Mg,Cu,Na,Si and Li2B4O7:Cu,Ag,P TL detectors

    International Nuclear Information System (INIS)

    Recently, two new types of 'tissue equivalent' thermoluminescent detectors (TLDs) have aroused attention: LiF:Mg,Cu,Na,Si and Li2B4O7:Cu,Ag,P. In this work the characteristics of both detectors were compared with the characteristics of the well-known type LiF:Mg,Ti detector, TLD-100. The following properties were investigated: The glow curve structures, relative sensitivity, batch homogeneity and uniformity, detection threshold, reproducibility of the response, linearity in the wide dose range and fading. Also, the energy dependence for medium and low energy X-rays was determined in the range of mean energies between 33 and 116 keV. The results confirmed 'tissue equivalency' of both new types in the investigated range of photon energies. LiF:Mg,Cu,Na,Si detector has very high sensitivity (∼75 times higher than that of TLD-100) and is convenient for use in a very low range of doses. Li2B4O7:Cu,Ag,P detector shows some improvements in comparison with the previously prepared types of lithium borate. The most important is the five times higher sensitivity than that of TLD-100. This detector is also very promising, especially in medical dosimetry. (authors)

  1. Multiple Electron Capture Processes in Slow Collisions of Ar9+ Ions with Na Atoms

    Institute of Scientific and Technical Information of China (English)

    ZhuXiaolong; ShaShan; LiuHuiping; WeiBaoren; MaXinwen; WangZhengling; CaoShiping; QianDongbing; YangZhihu

    2003-01-01

    Slow collisions of highly charged ions with neutral atoms and molecules are of great importance in basic atomic collision physics, Recently, we built a new research facility for atomic physics at the Institute of Modern Physics. We report here the multiple electron transfer processes in collisions of Ar9+ with Na gas target at energy of 180 keV.

  2. Raman spectroscopic study of molten SmCl3-ACl systems (A=Li,Na,K)

    International Nuclear Information System (INIS)

    Raman spectra of molten SmCl3-ACl systems (A=Li, Na, K) were measured at different compositions and temperatures. The spectra showed polarized peaks centered at about 256 cm-1 in the whole range of concentration and depolarized peaks at about 120 cm-1 in the low concentration range of SmCl3. These Raman shifts were identified as the totally symmetric stretching vibration υ1 and the degenerate bending vibration υ5 of octahedral SmCl63- complex anion, respectively. Peak splitting of the isotropic component was recognized clearly in the reduced Raman spectra of mixtures. Clustering of complex anions is thought to occur in the melts. However, the clustering might be restrained when the SmCl3 concentration became relatively low by adding LiCl, NaCl or KCl. The υ5 peak was the strongest at the SmCl3 concentration of 25 mol% in the SmCl3-KCl system among the three systems. The temperature effect on the Raman shift, reflecting the structural change, was negligibly small between 823 K and 1023 K. (orig.)

  3. Transport properties of molten-salt reactor fuel mixtures: the case of Na, Li, Be/F and Li, Be, Th/F salts

    International Nuclear Information System (INIS)

    In this paper we have compiled transport properties information, available, on two types of FLiBe based salt mixtures (Na,Li,Be/F and Li,Be,Th/F) that are presently of importance in the design of innovative molten-salt burner reactors. Estimated and/or experimental values measured (particularly, from prior US and Russian studies, as well our recent studies) are given for the following properties: viscosity, thermal conductivity, phase transition behaviour, heat capacity, density and thermal expansion. (author)

  4. l- and n-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO2

    International Nuclear Information System (INIS)

    The pulsed Li atomic beam produced in our experiment is based on controlled transversely-excited-atmospheric CO2 laser-induced ablation of a Li metal target. The atomic beam is propagated in vacuum or in CO2 gas at low pressure. Atoms in the beam are probed by laser-induced fluorescence spectroscopy. This allows the determination of time-of-flight and velocity distributions. Li Rydberg states (n=5--13) are populated in the beam by two-step pulsed-laser excitation. The excited atoms interact with CO2 molecules. l- and n-changing cross sections are deduced from the time evolution of the resonant or collision-induced fluorescence following this selective excitation. l-changing cross sections of the order of 104 A2 are measured; they increase with n as opposed to the plateau observed for Li/sup */ colliding with a diatomic molecule. This behavior is qualitatively well explained in the framework of the free-electron model. n yields n' changing processes with large cross sections (10--100 A2) are also observed even in the case of large electronic energy change (ΔE/sub nn'/>103 cm/sup -1/). These results can be interpreted in terms of resonant-electronic to vibrational energy transfers between Li Rydberg states and CO2 vibrational modes

  5. l- and n-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO2

    Science.gov (United States)

    Dubreuil, B.; Harnafi, M.

    1989-07-01

    The pulsed Li atomic beam produced in our experiment is based on controlled transversely-excited-atmospheric CO2 laser-induced ablation of a Li metal target. The atomic beam is propagated in vacuum or in CO2 gas at low pressure. Atoms in the beam are probed by laser-induced fluorescence spectroscopy. This allows the determination of time-of-flight and velocity distributions. Li Rydberg states (n=5-13) are populated in the beam by two-step pulsed-laser excitation. The excited atoms interact with CO2 molecules. l- and n-changing cross sections are deduced from the time evolution of the resonant or collision-induced fluorescence following this selective excitation. l-changing cross sections of the order of 104 AṦ are measured; they increase with n as opposed to the plateau observed for Li* colliding with a diatomic molecule. This behavior is qualitatively well explained in the framework of the free-electron model. n-->n' changing processes with large cross sections (10-100 AṦ) are also observed even in the case of large electronic energy change (ΔEnn'>103 cm-1). These results can be interpreted in terms of resonant-electronic to vibrational energy transfers between Li Rydberg states and CO2 vibrational modes.

  6. High-temperature nuclear magnetic resonance study of phase transition kinetics in LiNaSO4

    International Nuclear Information System (INIS)

    A new high-temperature NMR technique for measurements of the phase transition kinetics in solids has been developed. The technique allows measuring the time evolution of the volume of the appearing phase at controlled cooling rates. Developed method was applied to study the phase transition kinetics in the superionic conductor LiNaSO4. It was revealed that the phase transition in LiNaSO4 is governed by the diffusion-controlled growth of nuclei (“germs”). An effect of the crystallite rearrangement in the LiNaSO4 powder after cooling through the phase transition was also revealed. This effect was studied by means of high-temperature XRD and NMR

  7. Hydrogenation of Olefins Catalyzed by Highly Active Titanocene/NaH or n-BuLi Catalyst Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of the substituents on the cyclopentadienyl ring and the reducing agents on the catalytic activity and the stability of titanocene/NaH or n-BuLi systems for the hydrogenation of olefins were investigated. For the catalyst systems composed of titanocene/NaH or n-BuLi, the nature and the number of the substituents on the cyclopentadienyl ring control the catalytic behavior of those two systems. The effect of the reducing agent on the catalytic activity is relatively small. In addition, the characters of the hydrogenation of various olefins catalyzed respectively by Cp2TiCl2/NaH or n-BuLi systems were compared.

  8. The structure of Na2UCl6 and Li2UCl6 from multiphase powder neutron profile refinement

    International Nuclear Information System (INIS)

    The structures of Na2UCl6 and Li2UCl6 have been determined by powder neutron diffraction at room temperature in the presence of NaCl and LiCl respectively as impurity. Na2UCl6 crystallizes in space group P3-barm1, with a = 11.8062(9), c = 6.3243(2) A and Z = 3. The best description of Li2UCl6 was found in space group P63/mmc, a = 11.1915(5), c = 6.0356(1) A and Z = 3, with uranium and lithium ions disordered over the available octahedral sites. The results give the first illustration of the relative ease of analysing a two-phase mixture using a Rietveld profile program adapted to refine simultaneously more than one phase. (Auth.)

  9. Ab initio study of spectroscopic properties of bimetallic molecules MeB (where Me=Li, Na, K, Br, Cs, Fr) using CCSD(T) and MRCI methods

    International Nuclear Information System (INIS)

    For our study we have chosen a series of diatomic molecules MeB (where Me = Li, Na, K, Rb, Cs, Fr). These molecules present experimentally unknown species, hence we were motivated to predict theoretically potential energy curves, equilibrium bond lengths, harmonic frequencies, constants of anharmonicity, dipole moments and dissociation energies for the ground and low-lying excited states using high level ab initio techniques. Based on previous state averaged MRCI calculations in ANO-S basis set of NaB and KB molecules, we have focused on four lowest-lying electronic states, ground state 3Π and excited states 1Σ+, 1Π and 3Σ+. All four states dissociate to the atoms in ground states 2P1/2(B) and 2S1/2(Me). 3Π, 1Σ+, 1Π and 3Σ+ electronic states we investigated employing CCSD(T) method using relativistic ANO-RCC basis set. Our calculations include scalar relativistic effects via the second order one-component (spin-free) Douglas-Kroll-Hess Hamiltonian. Relativistic effects become remarkable in the case of heavy atoms, hence properties of CsB and FrB molecules may differ from trend of properties in row from LiB to FrB. Spectroscopic properties of particular state were obtained from the analysis of the potential energy curves using VIBROT and DUNHAM programs.

  10. The Competitive Influence of Li+, Na+, K+, Ag+, and H+ on the Fragmentation of a PEGylated Polymeric Excipient

    Science.gov (United States)

    Wei, Juan; Bristow, Anthony W. T.; O'Connor, Peter B.

    2015-01-01

    The collisionally activated dissociation (CAD) and electron capture dissociation (ECD) of doubly charged tocopheryl polyethylene glycol succinate (TPGS) have been examined. Li+, Na+, K+, Ag+, and H+ were selected in the study, and the competitive influence of each ion was investigated by fragmenting TPGS attached with two different cations, [M + X1 + X2]2+ (X1 and X2 refer to Li+, Na+, K+, Ag+, H+). For metallic adducts, CAD results show that the dissociation of ionic adducts from the precursor is most likely depending on the binding strength, where the affinity of each ion to the TPGS is in the order of Ag+ ≈ Li+ ˃ Na+ ˃ K+. Introducing more strongly bound adducts increases fragmentation. During ECD, however, the silver cation is lost most easily compared with the other alkali metal ions, but silver also shows a dominant role in producing fragmentations. Moreover, the charge carriers are lost in an order (Ag+ ˃ Na+ ˃ K+ ≥ Li+ where the loss of Ag is most easily) that appears to correlate with the standard reduction potential of the metallic ions (Ag+ ˃ Na+ ˃ K+ ˃ Li+). The ECD results suggest that the reduction potential of the charge carrier could be an important factor influencing the fragmentation, where the ion with a high reduction potential is more effective in capturing electrons, but may also be lost easily before leading to any fragmentation. Finally, a proton has the weakest binding with the TPGS according to the CAD results, and its dissociation in ECD follows the order of the reduction potential (Ag+ ˃ H+ ˃ Na+ ˃ K+ > Li+).

  11. Thermal Decomposition of Anhydrous Alkali Metal Dodecaborates M2B12H12 (M = Li, Na, K)

    OpenAIRE

    Liqing He; Hai-Wen Li; Etsuo Akiba

    2015-01-01

    Metal dodecaborates M2/nB12H12 are regarded as the dehydrogenation intermediates of metal borohydrides M(BH4)n that are expected to be high density hydrogen storage materials. In this work, thermal decomposition processes of anhydrous alkali metal dodecaborates M2B12H12 (M = Li, Na, K) synthesized by sintering of MBH4 (M = Li, Na, K) and B10H14 have been systematically investigated in order to understand its role in the dehydrogenation of M(BH4)n. Thermal decomposition of M2B12H12 indicates m...

  12. Adiabatic Channel Capture Theory Applied to Cold Atom-Molecule Reactions: Li + CaH -> LiH + Ca at 1 K

    CERN Document Server

    Tscherbul, Timur V

    2014-01-01

    We use quantum and classical adiabatic capture theories to study the chemical reaction Li + CaH -> LiH + Ca. Using a recently developed ab initio potential energy surface, which provides an accurate representation of long-range interactions in the entrance reaction channel, we calculate the adiabatic channel potentials by diagonalizing the atom-molecule Hamiltonian as a function of the atom-molecule separation. The resulting adiabatic channel potentials are used to calculate both the classical and quantum capture probabilities as a function of collision energy, as well as the temperature dependencies of the partial and total reaction rates. The calculated reaction rate agrees well with the measured value at 1 K [V. Singh et al., Phys. Rev. Lett. 108, 203201 (2012)], suggesting that the title reaction proceeds without an activation barrier. The calculated classical adiabatic capture rate agrees well with the quantum result in the multiple partial wave regime of relevance to the experiment. Significant differen...

  13. Dosimetric properties of the newly developed KLT-300 (LiF:Mg,Cu,Na,Si) TL detector

    International Nuclear Information System (INIS)

    The dosimetric properties of the newly developed KLT-300 (KAERI LiF:Mg,Cu,Na,Si TL detector) in KAERI (Korea Atomic Energy Research Institute) were investigated. The sensitivity of the TL detector was about 30 times higher than that of the TLD-100 by light integration. In the study of the dose linearity of the detector, the dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 to 662 keV. The results show that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively it was 0.0054. IEC Standard requires that the coefficient of variation shall not exceed 0.075. So, the reproducibility of this new TL detector sufficiently satisfied the IEC requirements. A detection threshold of the detector was investigated and found to be 70 nGy by Harshaw 4500 TLD Reader

  14. Dosimetric properties of the newly developed KLT-300 (LiF:Mg,Cu,Na,Si) TL detector.

    Science.gov (United States)

    Lee, J I; Kim, J L; Chang, S Y; Chung, K S; Choe, H S

    2004-01-01

    The dosimetric properties of the newly developed KLT-300 (KAERI LiF:Mg,Cu,Na,Si TL detector) in KAERI (Korea Atomic Energy Research Institute) were investigated. The sensitivity of the TL detector was about 30 times higher than that of the TLD-100 by light integration. In the study of the dose linearity of the detector, the dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 to 662 keV. The results show that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively it was 0.0054. IEC Standard requires that the coefficient of variation shall not exceed 0.075. So, the reproducibility of this new TL detector sufficiently satisfied the IEC requirements. A detection threshold of the detector was investigated and found to be 70 nGy by Harshaw 4500 TLD Reader. PMID:15856584

  15. Mixed lithium-sodium (LiNaCO3) and lithium-potassium (LiKCO3) carbonates for low temperature electrochemical applications: Structure, electronic properties and surface reconstruction from ab-initio calculations

    Science.gov (United States)

    Ricca, Chiara; Ringuedé, Armelle; Cassir, Michel; Adamo, Carlo; Labat, Frédéric

    2016-05-01

    The structural, electronic and surface properties of the mixed lithium-sodium (LiNaCO3) and lithium-potassium (LiKCO3) carbonates were studied through periodic calculations performed at the density functional theory (DFT) level, using three different exchange-correlation functionals. The hybrid functional PBE0 was found to be the best one to describe both geometric and electronic features of bulk LiNaCO3 and LiKCO3. Polar (001) and non-polar (110) low index surfaces were taken into account, the first one being found the most stable in both cases, after reconstruction. Both introduction of vacancies (R1) and octopolar terminations (R2) of (001), exposing Li ((001)Li) or Na ((001)Na) were described in detail. The computed stability order for the reconstructed surfaces in gas phase is: (001)R1Na > > (001)R1Li > (001)R2Na ≈ (001)R2Li. The obtained information, in particular regarding the electronic and surface properties, could be used in future to help understanding the role of mixed carbonates as component of oxide-carbonate electrolytes for low temperature solid oxide fuel cells (LT-SOFCs) applications, especially as reasonable starting points for dynamics calculations of liquid molten carbonates based systems.

  16. Chemically modified STM tips for atomic-resolution imaging of ultrathin NaCI films

    Institute of Scientific and Technical Information of China (English)

    Zhe Li[1; Koen Schouteden[1; Violeta lancu[1; Ewald Janssens[1; Peter Lievens[1; Chris Van Haesendonck[1; Jorge I. Cerda[2

    2015-01-01

    Cl-functionalized scanning tunneling microscopy (STM) tips are fabricated by modifying a tungsten STM tip in situ on islands of ultrathin NaCI(100) films on Au(111) surfaces. The functionalized tips are used to achieve clear atomic- resolution imaging of NaCI(100) islands. In comparison with bare metal tips, the chemically modified tips yield drastically enhanced spatial resolution as well as contrast reversal in STM topographs, implying that Na atoms, rather than C1 atoms, are imaged as protrusions. STM simulations based on a Green's function formalism reveal that the experimentally observed contrast reversal in the STM topographs is due to the highly localized character of the Cl-pz states at the tip apex. An additional remarkable characteristic of the modified tips is that in dI/dV maps, a Na atom appears as a ring with a diameter that depends crucially on the tip-sample distance.

  17. Bibliographical review about Na/Li geo-thermometry and lithium isotopes applied to worldwide geothermal waters. Final report

    International Nuclear Information System (INIS)

    This study is performed within the framework of the FP6 European project HITI (High Temperature Instruments for supercritical geothermal reservoir characterization and exploitation). This research project, co-funded by EU and the different partners, aims to provide geophysical and geochemical sensors and methods to evaluate deep geothermal wells up to supercritical conditions (T > 370 deg. C), which are more cost-effective than those of the conventional wells. A deep geothermal well is currently being drilled for this purpose into the Krafla area, Iceland, as part of the IDDP ('Iceland Deep Drilling Project') and with joint funding from Icelandic industry and science Institutes. Another deep well will be drilled in the Reykjanes peninsula, Iceland, within the framework of the same project. This study, a bibliographical review about the Na/Li geo-thermometer and lithium isotopes applied on the world geothermal waters, is the first step of the task envisaged by BRGM to use and validate the sodium-lithium (Na-Li) chemical geo-thermometer on Icelandic geothermal waters at temperatures ranging from 25 to 500 deg. C. In this study, more than 120 temperature and chemical data from world geothermal and oil-fields, sedimentary basins, oceanic ridges, emerged rifts and island arcs have been collected and investigated. These additional data have allowed to confirm and refine the three existing Na/Li thermometric relationships. Moreover, a new Na/Li thermometric relationship relative to the processes of seawater or dilute seawater-basalt interaction occurring in the oceanic ridges and emerged rifts is proposed. Even if the running of Na/Li is still poorly understood, the existence of a new thermometric relationship confirms that the Na/Li ratios not only depend on the temperature but also on other parameters such as the fluid salinity and origin, or the nature of the reservoir rocks in contact with the geothermal fluids. For most of the geothermal waters in contact with

  18. Vanadium dioxide - Reduced graphene oxide composite as cathode materials for rechargeable Li and Na batteries

    Science.gov (United States)

    Mahadi, Nurulhuda Binti; Park, Jae-Sang; Park, Jae-Ho; Chung, Kyung Yoon; Yi, Su Youl; Sun, Yang-Kook; Myung, Seung-Taek

    2016-09-01

    In this study, a metastable form of vanadium dioxide, denoted as VO2(B), has been successfully synthesized under solvothermal condition. However, the as-received VO2(B) suffers from fast capacity fading and poor high-rate performance. In order to overcome these problems, the as-received VO2(B) is solvothermally treated with reduced graphene oxide (rGO) to produce VO2(B)/rGO composite. As a result, the resulting electric conductivity of the VO2(B)/rGO composite is improved to ∼10-4 cm S-1 (from ∼10-7 S cm-1 for the as-received VO2(B)). Electrochemical data of the VO2(B)/rGO composite, tested in both Li and Na cells, shows markedly enhanced electrochemical performance compared to bare VO2(B). The effect of electro-conducting rGO is more evident at high rates.

  19. Modern battery electrolytes: ion-ion interactions in Li+/Na+ conductors from DFT calculations.

    Science.gov (United States)

    Jónsson, Erlendur; Johansson, Patrik

    2012-08-14

    Sodium-ion batteries, the sodium counterpart of the ubiquitous lithium-ion batteries, are currently being developed as a complementary technology to assure resource availability. As battery electrolytes tend to be one of the more limiting parts of any battery for both performance and life-length, chemical and physical data on sodium-ion battery electrolytes are important for rational development. Here the cation-anion interaction, a key property of any salt used in an electrolyte, of a number of salts is probed using numerous DFT methods via the ion-pair dissociation reaction: AlkAn ⇌ Alk(+) + An(-), where An(-) is any anion and Alk(+) is Na(+) or Li(+), the latter used here for a straight-forward literature and methodology comparison. Furthermore, the applicability of different DFT functionals for these types of calculations is benchmarked vs. a robust higher accuracy method (G4MP2). PMID:22751486

  20. Simmonsite, Na2LiAlF6, a new mineral from the Zapot amazonite-topazzinnwaldite pegmatite, Hawthorne, Nevada, U.S.A

    Science.gov (United States)

    Foord, E.E.; O'Connor, J. T.; Hughes, J.M.; Sutley, S.J.; Falster, A.U.; Soregaroli, A.E.; Lichte, F.E.; Kile, D.E.

    1999-01-01

    Simmonsite, Na2LiAlF6, a new mineral of pegmatitic-hydrothermal origin, occurs in a late-stage breccia pipe structure that cuts the Zapot amazonite-topaz-zinnvvaldite pegmatite located in the Gillis Range, Mineral Co., Nevada, U.S.A. The mineral is intimately intergrown with cryolite, cryolithionite and trace elpasolite. A secondary assemblage of other alumino-fluoride minerals and a second generation of cryolithionite has formed from the primary assemblage. The mineral is monoclinic, P21 or P21/m, a = 7.5006(6) A??, b = 7.474(1) A??, c = 7.503(1) A??, ??= 90.847(9) ??, V=420.6(1) A??3, Z = 4. The four strongest diffraction maxima [d(A??), likl, I/I100] are (4.33, 111 and 111, 100); (1.877, 400 and 004, 90); (2.25, 13T, 113, 131 and 311, 70); and (2.65, 220, 202, 022, 60). Simmonsite is pale buff cream with white streak, somewhat greasy, translucent to transparent, Mohs hardness of 2.5-3, no distinct cleavage, subconchoidal fracture, no parting, not extremely brittle, Dm is 3.05(2) g/cm3, and Dc is 3.06(1) g/cm3. The mineral is biaxial, very nearly Isotropie, N is 1.359(1) for ?? = 589 nm, and birefringence is 0.0009. Electron microprobe analyses gave (wt%) Na = 23.4, Al = 13.9, F = 58.6, Li = 3.56 (calculated), with a total of 99.46. The empirical formula (based on 6 F atoms) is Na1.98Li1.00 ooAl|ooF6. The crystal structure was not solved, presumably because of unit-cell scale twinning, but similarities to the perovskite-type structure exist. The mineral is named for William B. Simmons, Professor of Mineralogy and Petrology, University of New Orleans, New Orleans.

  1. Structural and impurity phase transitions of LiNaSO{sub 4}:RE probed using cathodo-thermoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Maghrabi, M [Department of Physics, Hashemite University, PO Box 150459, Zarqa 13115 (Jordan); Finch, A A [School of Geography and Geosciences, University of St Andrews, Fife KY16 9AL (United Kingdom); Townsend, P D [Science and Technology, University of Sussex, Brighton, BN1 9QH (United Kingdom)], E-mail: muf.mug@hu.edu.jo

    2008-11-12

    Spectrally resolved cathodo-thermoluminescence spectra of rare earth (RE) doped LiNaSO{sub 4} measured from 20 to 673 K reveal several anomalies in the RE emission lines and intensities. The low (20-300 K) temperature data show a discontinuous change in intensity at {approx}170 K that is either a marked intensity enhancement or a drop truncating the entire spectrum. Such an effect on the host luminescence has previously been assigned to a transition between cubic and hexagonal polymorphs of ice nanoparticle inclusions. Similar, but less profound anomalies are seen above room temperature (300-673 K) where the changes take the form of either a discontinuity in intensity at {approx}480 K or reduced intensity in the range 430-530 K. There are changes in the relative intensities of different emission lines of the same dopant in this temperature range. Such high temperature variations are ascribed to structural phase changes within the LiNaSO{sub 4} crystals. The behaviours may result from Li-poor surfaces or twin boundaries behaving like Na{sub 2}SO{sub 4}. This phase change is suggested in the open literature for LiNaSO{sub 4} but not yet fully documented, perhaps because the effects span a wide range of temperatures or due to experimental features inherent in most luminescence facilities.

  2. Electronic structures of efficient MBiO3 (M = Li, Na, K, Ag) photocatalyst

    Science.gov (United States)

    Wen-Liu, Zhou; Zong-Yan, Zhao

    2016-03-01

    In order to deepen the understanding of the relationship between fundamental properties (including: microstructure and composition) and photocatalytic performance, four bismuthate compounds, including: LiBiO3, NaBiO3, KBiO3, and AgBiO3, are regarded as research examples in the present work, because they have particular crystal structures and similar compositions. Using density functional theory calculations, their structural, electronic, and optical properties are investigated and compared systematically. First of all, the calculated results of crystal structures and optical properties are in agreement with available published experimental data. Based on the calculated results, it is found that the tunneled or layered micro-structural properties lead to the stronger interaction between bismuth and oxygen, and the weaker interaction between alkaline-earth metal and [BiO6] octahedron, resulting in the feature of multi-band gaps in the cases of LiBiO3, NaBiO3, and KBiO3. This conclusion is supported by the case of AgBiO3, in which the feature of multi-band gaps disappears, due to the stronger interaction between the noble metal and [BiO6] octahedron. These properties have significant advantages in the photocatalytic performance: absorbing low energy photons, rapidly transferring energy carriers. Furthermore, the features of electronic structures of bismuthate compounds are well reflected by the absorption spectra, which could be confirmed by experimental measurements in practice. Combined with the calculated results, it could be considered that the crystal structures and compositions of the photocatalyst determine the electronic structures and optical properties, and subsequently determine the corresponding photocatalytic performance. Thus, a novel Bi-based photocatalyst driven by visible-light could be designed by utilizing specific compositions to form favorable electronic structures or specific micro-structures to form a beneficial channel for energy carriers

  3. Assessment of the release of atomic Na from a burning black liquor droplet using quantitative PLIF

    Energy Technology Data Exchange (ETDEWEB)

    Saw, Woei L.; Nathan, Graham J. [Centre for Energy Technology, The Environment Institute, School of Mechanical Engineering, The University of Adelaide, SA 5005 (Australia); Ashman, Peter J.; Alwahabi, Zeyad T. [Centre for Energy Technology, The Environment Institute, School of Chemical Engineering, The University of Adelaide, SA 5005 (Australia)

    2009-07-15

    The quantitative measurement of atomic sodium (Na) release, at high concentration, from a burning black liquor droplet has been demonstrated using a planar laser-induced fluorescence (PLIF) technique, corrected for fluorescence trapping. The local temperature of the particle was measured to be approximately 1700 C, at a height of 10 mm above a flat flame burner. The PLIF technique was used to assess the temporal release of atomic Na from the combustion of black liquor and compare it with the Na concentration in the remaining smelt. A first-order model was made to provide insight using a simple Plug Flow Reactor model based on the independently measured concentration of residual Na in the smelt as a function of time. This model also required the dilution ratio of the combustion products in the flat flame entrained into the plume gas from the black liquor particle to be estimated. The key findings of these studies are: (i) the peak concentration of atomic Na from the combustion of the black liquor droplets is around 1.4 ppm; (ii) very little atomic Na is present during the drying, devolatilisation or char combustion stages; and (iii) the presence of atomic Na during smelt phase dominates over that from the other combustion stages. (author)

  4. Native defects affecting the Li atom distribution tune the optical emission of ZnO:Li epitaxial thin film

    International Nuclear Information System (INIS)

    It is found that the oxygen vacancy (VO) defect concentration affecting the separation between individual species in LiZn-Lii complex influences the optical emission property of Li0.06Zn0.94O epitaxial thin film grown by pulsed laser deposition. The film grown under low oxygen partial pressure (n-type conductivity)/higher partial pressure (resistive-type) has broad emission at ∼2.99 eV/∼2.1 eV and a narrower emission at 3.63 eV/3.56 eV, respectively. First principle based mBJLDA electronic structure calculation suggests that the emission at 2.99 eV is due to the LiZn-Lii pair complex and the emission at 2.1 eV is when the component species are away from each other

  5. Native defects affecting the Li atom distribution tune the optical emission of ZnO:Li epitaxial thin film

    Science.gov (United States)

    Sahu, R.; Dileep, K.; Loukya, B.; Datta, R.

    2014-02-01

    It is found that the oxygen vacancy (VO) defect concentration affecting the separation between individual species in LiZn-Lii complex influences the optical emission property of Li0.06Zn0.94O epitaxial thin film grown by pulsed laser deposition. The film grown under low oxygen partial pressure (n-type conductivity)/higher partial pressure (resistive-type) has broad emission at ˜2.99 eV/˜2.1 eV and a narrower emission at 3.63 eV/3.56 eV, respectively. First principle based mBJLDA electronic structure calculation suggests that the emission at 2.99 eV is due to the LiZn-Lii pair complex and the emission at 2.1 eV is when the component species are away from each other.

  6. Characterization of Precipitation in Al-Li Alloy AA2195 by means of Atom Probe Tomography and Transmission Electron Microscopy

    KAUST Repository

    Khushaim, Muna

    2015-05-19

    The microstructure of the commercial alloy AA2195 was investigated on the nanoscale after conducting T8 tempering. This particular thermomechanical treatment of the specimen resulted in the formation of platelet-shaped T 1 Al 2 CuLi / θ ′ Al 2 Cu precipitates within the Al matrix. The electrochemically prepared samples were analyzed by scanning transmission electron microscopy and atom probe tomography for chemical mapping. The θ ′ platelets, which are less than 2 nm thick, have the stoichiometric composition consistent with the expected Al 2 Cu equilibrium composition. Additionally, the Li distribution inside the θ ′ platelets was found to equal the same value as in the matrix. The equally thin T 1 platelet deviates from the formula (Al 2 CuLi) in its stoichiometry and shows Mg enrichment inside the platelet without any indication of a higher segregation level at the precipitate/matrix interface. The deviation from the (Al 2 CuLi) stoichiometry cannot be simply interpreted as a consequence of artifacts when measuring the Cu and Li concentrations inside the T 1 platelet. The results show rather a strong hint for a true lower Li and Cu contents, hence supporting reasonably the hypothesis that the real chemical composition for the thin T 1 platelet in the T8 tempering condition differs from the equilibrium composition of the thermodynamic stable bulk phase.

  7. Analysis of the glow curves obtained from LiF:Mg,Cu,Na,Si TL materials using the general order kinetics model

    International Nuclear Information System (INIS)

    Three-dimensional thermoluminescence (TL) spectra based on temperature, wavelength and intensity for newly developed LiF:Mg,Cu,Na,Si TL material at the Korea Atomic Energy Research Institute were measured and analysed. The glow curves were obtained by integration of luminescence intensity over all wavelengths at each temperature, and various trapping parameters related to the traps were determined by analysing these curves. A computerised glow curve deconvolution method which was based on the general order kinetics model was used for the glow curve analysis. The glow curves of LiF:Mg,Cu,Na,Si TL material were deconvoluted to six isolated glow curves which have peak temperatures at 333, 374, 426, 466, 483 and 516 K. The main glow peak of peak temperature at 466 K had activation energy of 2.06 eV and a kinetic order of 1.05. This TL material was also found to have three recommendation centres, 1.80 eV, 2.88 eV and 3.27 eV by analysis of the TL spectra. (author)

  8. The structural behaviour of Na2U6Cl6 and Li2UCl6 observed by neutron powder diffraction

    International Nuclear Information System (INIS)

    The structural behaviour of the Na2U6Cl6 and Li2UCl6 is studied as a function of temperature by neutron powder diffraction. The high temperature structures of compound are presented. The Na2U6Cl6 up to 711 K, crystallizes in a trigonal unit cell, with space group P-3m1. The lattice constants at 711 K are: a = b = 11.951(7), c = 6.568(5) A. It is shown that at room temperature the Li2UCl6 crystallizes in hexagonal unit cell, with space group P63/mmc. The unit cell constants are: a = b = 11.174(1), c 18.104(3) A. In the room temperature structure, the sublattices of uranium and lithium ions are disordered. The high temperature structures of Li2UCl6 have been determined. It is shown that above 640 K the Li2UCl6 crystallizes in a trigonal unit cell (space group P-3c1). At 711 K the lattice cell constants are: a = b = 11.483(4), c = 12.693(5) A. It has been found that in contrast to room temperature phase, the sublattice of uranium ions is ordered in a manner similar to Na2U6Cl6 . The structural and electrical properties of both compounds are discussed. (author)

  9. Utjecaj spola, tjelesne mase pri klanju i proizvodne sezone na &zikalno-kemijska svojstva mesa janjadi ličke pramenke

    OpenAIRE

    Kaić, dr.sc. Ana; Mioč, prof.dr.sc. Boro; Kasap, dipl.ing.agr., Ante; Živković, Leopold

    2014-01-01

    Cilj ovog istraživanja bio je utvrditi utjecaj spola, tjelesne mase pri klanju i proizvodne sezone na vrijednosti pH, boju, gubitak mesnog soka i osnovni kemijski sastav mesa janjadi ličke pramenke. Janjad ličke pramenke je uzgojena na obiteljskom poljoprivrednom gos- podarstvu u Ličko-senjskoj županiji tijekom 2010. i 2011. godine. Odabrana janjad je bila ujednačene zastupljenosti po spolu i zaklana s navršenih 5 mjeseci. Statistički značajne razlike između muške i ženske janjadi li...

  10. A comparative first-principles study of the lithiation, sodiation, and magnesiation of black phosphorus for Li-, Na-, and Mg-ion batteries.

    Science.gov (United States)

    Hembram, K P S S; Jung, Hyun; Yeo, Byung Chul; Pai, Sung Jin; Lee, Heon Ju; Lee, Kwang-Ryeol; Han, Sang Soo

    2016-08-01

    Using first-principles calculations, we describe and compare atomistic lithiation, sodiation, and magnesiation processes in black phosphorous with a layered structure similar to graphite for Li-, Na-, and Mg-ion batteries because graphite is not considered to be an electrode material for Na- and Mg-ion batteries. The three processes are similar in that an intercalation mechanism occurs at low Li/Na/Mg concentrations, and then further insertion of Li/Na/Mg leads to a change from the intercalation mechanism to an alloying process. Li and Mg show a columnar intercalation mechanism and prefer to locate in different phosphorene layers, while Na shows a planar intercalation mechanism and preferentially localizes in the same layer. In addition, we compare the mechanical properties of black phosphorous during lithiation, sodiation, and magnesiation. Interestingly, lithiation and sodiation at high concentrations (Li2P and Na2P) lead to the softening of black phosphorous, whereas magnesiation shows a hardening phenomenon. In addition, the diffusion of Li/Na/Mg in black phosphorus during the intercalation process is an easy process along one-dimensional channels in black phosphorus with marginal energy barriers. The diffusion of Li has a lower energy barrier in black phosphorus than in graphite. PMID:27425818

  11. Magnetic control of ultra-cold $^6$Li and $^{174}$Yb($^3P_2$) atom mixtures with Feshbach resonances

    CERN Document Server

    Petrov, Alexander; Kotochigova, Svetlana

    2015-01-01

    We theoretically evaluate the feasibility to form magnetically-tunable Feshbach molecules in collisions between fermionic $^6$Li atoms and bosonic metastable $^{174}$Yb($^3$P$_2$) atoms. In contrast to the well-studied alkali-metal atom collisions, collisions with meta-stable atoms are highly anisotropic. Our first-principle coupled-channel calculation of these collisions reveals the existence of broad Feshbach resonances due to the combined effect of anisotropic-molecular and atomic-hyperfine interactions. In order to fit our predictions to the specific positions of experimentally-observed broad resonance structures \\cite{Deep2015} we optimized the shape of the short-range potentials by direct least-square fitting. This allowed us to identify the dominant resonance by its leading angular momentum quantum numbers and describe the role of collisional anisotropy in the creation and broadening of this and other resonances.

  12. Determination of Na and Fe in high level liquid waste by closure atom absorption spectrum

    International Nuclear Information System (INIS)

    A method of measuring Na and Fe in High Level Liquid Waste (HLLW) by gloved fire atom absorption spectrometry was established. High Level Liquid Waste (HLLW) could be directly measured. The stabilization of the method is good. The operation is convenience and fast. The precision (RSD) of Na and Fe is better than 2% and 4% respectively. The precision (RSD) of Na and Fe is better than 2% and 4% respectively. The standard added-recovery for Na and Fe is 98.7% and 96.8% respectively. The results are well agreed with that obtained by other method and passed through F test. (authors)

  13. Simultaneous size and luminescence control of NaYF4:Yb3+/RE3+ (RE = Tm, Ho) microcrystals via Li+ doping

    Science.gov (United States)

    Lin, Hao; Xu, Dekang; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

    2015-07-01

    Enhancement of upconversion (UC) luminescence is imperative for the applications of UC microcrystals (MCs). In this work, NaYF4:Yb3+/RE3+ (RE = Tm, Ho) MCs via Li+ doping were successfully prepared by a simple hydrothermal process with the assistance of citric acid. The UC luminescence intensities of NaYF4:Yb3+/RE3+ (RE = Tm, Ho) are significantly enhanced via Li+ doping at different concentrations. Compared to Li+-absent sample, UC luminescence intensities of blue emission (477 nm) and red emission (649 nm) in NaYF4:Yb3+/Tm3+ MCs via 15 mol% Li+ doping are improved by 10 and 9 times, respectively; UC luminescence intensities of green emission (538 nm) and red emission (644 nm) in NaYF4:Yb3+/Ho3+ MCs via 15 mol% Li+ doping are improved by 12 and 3 times, respectively. The mechanism of the enhancement via Li+ doping is discussed in details, which may be attributed to the fact that Li+ doping can cause the distortion of the local symmetry around RE ions. Our results indicate that the enhanced UC luminescence of NaYF4:Yb3+/RE3+ (RE = Tm, Ho) MCs via Li+ doping may have potential applications in optoelectronic devices such as solar cells and plasma display panel.

  14. Fluorescence studies on 20Na and excited neon atoms in proton-induced plasmas

    International Nuclear Information System (INIS)

    In this thesis, an experimental study on the application of the optical fluorescence technique for the detection of excited and ground-state atoms in a neon plasma produced by 20-MeV protons is presented. By making use of a continuous-wave dye laser tuned to the D2-line of sodium, the 20Na atoms, produced via the reaction 20Ne(p,h)20Na, were excited and the intensity of the fluorescence light measured for several positions in the reaction vessel. From the time dependence of the fluorescence signal after a period of production by the proton beam, the diffusion of the 20Na atoms through the reaction vessel could be studied. Using single-mode operation of the dye laser the absorption line shape of the 23Na D-lines and the isotope shift of the 20Na D-lines with respect to the 23Na D-lines were determined. The proton beam was used as a well-defined excitation source to study the kinetic behaviour of neon atoms in the 1S2, 1S4 and 1S5 states. To learn the effect of plasma conditions on the results of the experiments, the electron density and the electron temperature in the plasma were measured

  15. Understanding Li-ion battery processes at the atomic to nano-scale.

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Yongjie (Rice University, Houston, TX); Subramanian, Arunkumar; Hudak, Nicholas; Sullivan, John Patrick; Shaw, Michael J.; Huang, Jian Yu

    2010-05-01

    Reducing battery materials to nano-scale dimensions may improve battery performance while maintaining the use of low-cost materials. However, we need better characterization tools with atomic to nano-scale resolution in order to understand degradation mechanisms and the structural and mechanical changes that occur in these new materials during battery cycling. To meet this need, we have developed a micro-electromechanical systems (MEMS)-based platform for performing electrochemical measurements using volatile electrolytes inside a transmission electron microscope (TEM). This platform uses flip-chip assembly with special alignment features and multiple buried electrode configurations. In addition to this platform, we have developed an unsealed platform that permits in situ TEM electrochemistry using ionic liquid electrolytes. As a test of these platform concepts, we have assembled MnO{sub 2} nanowires on to the platform using dielectrophoresis and have examined their electrical and structural changes as a function of lithiation. These results reveal a large irreversible drop in electronic conductance and the creation of a high degree of lattice disorder following lithiation of the nanowires. From these initial results, we conclude that the future full development of in situ TEM characterization tools will enable important mechanistic understanding of Li-ion battery materials.

  16. Spectroscopic and Physical Properties of Mn2+ spin probe in ROP2O5-ZnO-Pb3O4 (R=Li, Na and K Glasses

    Directory of Open Access Journals (Sweden)

    S. Sreehari Sastry

    2015-04-01

    Full Text Available RO-P2O5-ZnO-Pb3O4 (R=Li, Na and K glasses containing 0.1concentrations of MnO have been prepared. The structural, optical and physical properties of prepared glasses are studied by XRD, UV-Visible, EPR and FTIR techniques. The nature of local symmetry and structural information of the neighboring atoms of dopant ions (Mn2+ in the host matrix have been understood by evaluating the crystal field strength (Dq and Racah (B & C parameters. The combined analysis of optical absorption and EPR spectroscopy has indicated that the manganese ions exist in Mn2+ (in octahedral local coordination sites. FTIR results showed that PO4 are the main structural unit of the glass system and the manganese ions are located in the glass matrix network.

  17. X-ray and MAS NMR characterization of the thermal transformation of Li(Na)-Y zeolite to lithium aluminosilicates

    International Nuclear Information System (INIS)

    The high temperature thermal transformation of Li-exchanged Na-Y zeolite has been investigated by X-ray diffraction and /sup 29/Si MAS NMR studies. At 7000C, the zeolite was transformed into an amorphous phase and upon further heating to 8000C, formation of lithium aluminosilicate with high-quartz structure, in addition to an amorphous phase, was noted. When heated above 9000C, the high-quartz structure was transformed into a β-spodumene related solid solution. X-ray and MAS NMR studies indicate the β-spodumene solid solution formed has the composition close to (Li/sub 0.23/Na/sub 0.06/)A iota /sub 0.29/Si/sub 0.71/O/sub 2/, which is in agreement with chemical analysis

  18. TL characteristics of Ce3+-doped NaLi2PO4 TLD phosphor

    International Nuclear Information System (INIS)

    Ce3+-doped NaLi2PO4 orthophosphate (with different impurity concentrations, i.e., 0.01-0.3 mol%) was prepared by a solid state reaction method. Formation of the material was confirmed using powder X-ray diffraction analysis. TL intensity was found to be the highest for the material having impurity concentration 0.2 mol% after annealing it at around 600 K for 1 h and subsequently quenching to room temperature. A typical glow curve consists of three peaks at around 454, 493 and 570 K (dosimetry peak). Good sensitivity (∼8 times more than that of TLD-100), low fading (∼15 % in 2 months), low-Z material (Zeff ≈ 10.8), very wide dose response (i.e., 0.1 Gy-1.0 kGy of γ rays) make the material a 'good' thermoluminescent dosimeter (TLD) phosphor suitable for personnel, medical and environmental dosimetry of high-energy radiation using TL. It could also be used during cancer therapy and sterilization of food where high doses are needed to be monitored. (author)

  19. Thermoluminescence emission spectra for the LiF:Mg,Cu,Na,Si thermoluminescent materials with various concentrations of the dopants (3-D measurement).

    Science.gov (United States)

    Lee, J I; Lee, D; Kim, J L; Chang, S Y

    2006-01-01

    The thermoluminescence (TL) emission spectra from LiF TL materials, called KLT-300 (LiF:Mg,Cu,Na,Si) with various dopant concentrations are measured and analysed. These KLT-300 materials were developed by the Korea Atomic Energy Research Institute (KAERI) to achieve an enhancement of the thermal stability in TL readings. Six types of samples are prepared with different dopant concentrations in the following ranges; Mg (0-0.20 mol%), Cu (0-0.05 mol%), Na and Si (0-0.9 mol%). The spectra measurements are carried out for the six types of samples using a TL emission spectra measurement device. The spectra measurement device consists of a monochromator, photomultiplier tube and temperature control unit to thermally stimulate the samples. The measured data shows the light emission during heating of the sample as a function of temperature and wavelength (three-dimensional TL spectra). The spectra were analysed using a method of deconvolution based on gaussian curve. The wavelength of a main peak of the emission spectra changes depending on the existence of the Cu dopant, while intensity of the spectra rapidly changes with the Cu dopant concentrations. The 385 nm emission is mainly observed in all the spectra from the samples with the Cu dopant, but in those from the samples without the Cu dopant a very weak 401 nm emission is mainly observed. However, any change in the wavelength at a main peak of the TL emission spectra from the sample materials with Na and Si dopants is not observed but that in the intensity at a peak of the spectra is observed. PMID:16644972

  20. Thermoluminescence emission spectra for the LiF:Mg,Cu,Na,Si thermoluminescent materials with various concentrations of the dopants (3-D measurement)

    International Nuclear Information System (INIS)

    The thermoluminescence (TL) emission spectra from LiF TL materials, called KLT-300 (LiF:Mg,Cu,Na,Si) with various dopant concentrations are measured and analysed. These KLT-300 materials were developed by the Korea Atomic Energy Research Inst. (KAERI) to achieve an enhancement of the thermal stability in TL readings. Six types of samples are prepared with different dopant concentrations in the following ranges; Mg (0-0.20 mol%), Cu (0-0.05 mol%), Na and Si (0-0.9 mol%). The spectra measurements are carried out for the six types of samples using a TL emission spectra measurement device. The spectra measurement device consists of a monochromator, photomultiplier tube and temperature control unit to thermally stimulate the samples. The measured data shows the light emission during heating of the sample as a function of temperature and wavelength (three-dimensional TL spectra). The spectra were analysed using a method of deconvolution based on gaussian curve. The wavelength of a main peak of the emission spectra changes depending on the existence of the Cu dopant, while intensity of the spectra rapidly changes with the Cu dopant concentrations. The 385 nm emission is mainly observed in all the spectra from the samples with the Cu dopant, but in those from the samples without the Cu dopant a very weak 401 nm emission is mainly observed. However, any change in the wavelength at a main peak of the TL emission spectra from the sample materials with Na and Si dopants is not observed but that in the intensity at a peak of the spectra is observed. (authors)

  1. Determination of Li, Na, K and Cs in UO2 by flame ASS/flame AES with prion TBP levextrel resin chromatographic separation

    International Nuclear Information System (INIS)

    An analytical method for the determination of Li, Na, K and Cs in uranium dioxide is developed. The uranium dioxide powder is dissolved in nitric acid, then the sample solution is passed through a TBP levextrel chromatographic column. 5.5 mol · l-1 HNO3 is used as eluent. The eluate is analysed by air-C2H2AAS for Li, Na and K, and air-C2H2 AES for Cs, respectively. The concentration range determined Li, Na, K and Cs in UO2 is 2 x 10-6-20 x 10-6 for 0.5 g sample. The recovery is from 96% to 103% and RSD is 3%, 5%, 7% and 6% for Li, Na, K and Cs, respectively. This method is simple and reliant. It was accepted as a national standard analytical method in China now

  2. Using atomic diffraction of Na from material gratings to measure atom-surface interactions

    International Nuclear Information System (INIS)

    In atom optics a material structure is commonly regarded as an amplitude mask for atom waves. However, atomic diffraction patterns formed using material gratings indicate that material structures also operate as phase masks. In this study a well collimated beam of sodium atoms is used to illuminate a silicon nitride grating with a period of 100 nm. During passage through the grating slots atoms acquire a phase shift due to the van der Waals (vdW) interaction with the grating walls. As a result the relative intensities of the matter-wave diffraction peaks deviate from those expected for a purely absorbing grating. Thus a complex transmission function is required to explain the observed diffraction envelopes. An optics perspective to the theory of atomic diffraction from material gratings is put forth in the hopes of providing a more intuitive picture concerning the influence of the vdW potential. The van der Waals coefficient C3=2.7±0.8 meV nm3 is determined by fitting a modified Fresnel optical theory to the experimental data. This value of C3 is consistent with a van der Waals interaction between atomic sodium and a silicon nitride surface

  3. Dependence of the glow curve structure for a new KLT-300 (LiF:Mg, Cu, Na, Si) TL detector on the dopants concentration

    International Nuclear Information System (INIS)

    A new TL detector KLT-300 (KAERI LiF TL detector doped with Mg, Cu, Na, Si) for personal and medical monitoring purposes was recently developed at KAERI (Korea Atomic Energy Research Institute). The main parameters in preparation of the detector were the concentration of the dopants. In this research, the investigation of the glow curve structure for KLT-300 was performed with respect to the various concentrations of the Mg (0-0.25 mol%), Cu (0-0.07 mol%), Na and Si (0-1.5 mol%) dopants. With increasing the Cu concentration, the intensity of the main peak was very rapidly intensified and reached the maximum at a concentration of 0.05 mol% and then the high temperature peak was very rapidly reduced. The dependence of the main peak intensity on the Mg concentration exhibits a sharp maximum at 0.2 mol%. The intensity of the high temperature peak tends to slightly rise with an increasing Mg concentration. With increasing Na and Si concentrations, the main peak intensity was slightly intensified and reached a maximum at 0.9 mol%. (author)

  4. Environmentally-friendly aqueous Li (or Na)-ion battery with fast electrode kinetics and super-long life.

    Science.gov (United States)

    Dong, Xiaoli; Chen, Long; Liu, Jingyuan; Haller, Servane; Wang, Yonggang; Xia, Yongyao

    2016-01-01

    Current rechargeable batteries generally display limited cycle life and slow electrode kinetics and contain environmentally unfriendly components. Furthermore, their operation depends on the redox reactions of metal elements. We present an original battery system that depends on the redox of I(-)/I3 (-) couple in liquid cathode and the reversible enolization in polyimide anode, accompanied by Li(+) (or Na(+)) diffusion between cathode and anode through a Li(+)/Na(+) exchange polymer membrane. There are no metal element-based redox reactions in this battery, and Li(+) (or Na(+)) is only used for charge transfer. Moreover, the components (electrolyte/electrode) of this system are environment-friendly. Both electrodes are demonstrated to have very fast kinetics, which gives the battery a supercapacitor-like high power. It can even be cycled 50,000 times when operated within the electrochemical window of 0 to 1.6 V. Such a system might shed light on the design of high-safety and low-cost batteries for grid-scale energy storage. PMID:26844298

  5. Doping Li and K into Na2ZrO3 Sorbent to Improve Its CO2 Capture Capability

    Science.gov (United States)

    Duan, Yuhua

    Carbon dioxide is one of the major combustion products which once released into the air can contribute to global climate change. Solid sorbents have been reported in several previous studies to be promising candidates for CO2 sorbent applications due to their high CO2 absorption capacities at moderate working temperatures. However, at a given CO2 pressure, the turnover temperature (Tt) of an individual solid capture CO2 reaction is fixed and may be outside the operating temperature range (ΔTo) for a particularly capture technology. In order to shift such Tt for a solid into the range of ΔTo, its corresponding thermodynamic property must be changed by changing its structure by reacting (mixing) with other materials or doping with other elements. As an example, by combining thermodynamic database searching with ab initio thermodynamics calculations, in this work, we explored the Li- and K-doping effects on the Tt shifts of Na2ZrO3 at different doping levels. The obtained results showed that compared to pure Na2ZrO3, the Li- and K-doped mixtures Na2-αMαZrO3 (M =Li, K) have lower Tt and higher CO2 capture capacities.

  6. Using Atomic Diffraction of Na from Material Gratings to Measure Atom-Surface Interactions

    CERN Document Server

    Perreault, J D; Savas, T A; Perreault, John D.; Cronin, Alexander D.

    2003-01-01

    In atom optics a material structure is commonly regarded as an amplitude mask for atom waves. However, atomic diffraction patterns formed using material gratings indicate that material structures also operate as phase masks. In this study a well collimated beam of sodium atoms is used to illuminate a silicon nitride grating with a period of 100 nm. During passage through the grating slots atoms acquire a phase shift due to the van der Waals interaction with the grating walls. As a result the relative intensities of the matter-wave diffraction peaks deviate from those expected for a purely absorbing grating. Thus a complex transmission function is required to explain the observed diffraction envelopes. An optics perspective to the theory of atomic diffraction from material gratings is put forth in the hopes of providing a more intuitive picture concerning the influence of the vdW potential. The van der Waals coefficient $C_{3} = 2.7\\pm 0.8{meV nm}^{3}$ is determined by fitting a modified Fresnel optical theory...

  7. Efficient plasma-enhanced method for layered LiNi1/3Co1/3Mn1/3O2 cathodes with sulfur atom-scale modification for superior-performance Li-ion batteries

    Science.gov (United States)

    Jiang, Qianqian; Chen, Ning; Liu, Dongdong; Wang, Shuangyin; Zhang, Han

    2016-05-01

    In order to improve the electrochemical performance of LiNi1/3Co1/3Mn1/3O2 as a lithium insertion positive electrode material, atom-scale modification was realized to obtain the layered oxysulfide LiNi1/3Co1/3Mn1/3O2-xSx using a novel plasma-enhanced doping strategy. The structure and electrochemical performance of LiNi1/3Co1/3Mn1/3O2-xSx are investigated systematically, which confirms that the S doping can make the structure stable and benefit the electrochemical performance. The phys-chemical characterizations indicate that oxygen atoms in the initial LiNi1/3Co1/3Mn1/3O2 have been partially replaced by S atoms. It should be pointed out that the atom-scale modification does not significantly alter the intrinsic structure of the cathode. Compared to the pristine material, the LiNi1/3Co1/3Mn1/3O2-xSx shows a superior performance with a higher capacity (200.4 mA h g-1) and a significantly improved cycling stability (maintaining 94.46% of its initial discharge capacity after 100 cycles). Moreover, it has an excellent rate performance especially at elevated performance, which is probably due to the faster Li+ transportation after S doping into the layered structure. All the results show that the atom-scale modification with sulfur atoms on LiNi1/3Co1/3Mn1/3O2, which significantly improved the electrochemical performance, offers a novel anionic doping strategy to realize the atom-scale modification of electrode materials to improve their electrochemical performance.In order to improve the electrochemical performance of LiNi1/3Co1/3Mn1/3O2 as a lithium insertion positive electrode material, atom-scale modification was realized to obtain the layered oxysulfide LiNi1/3Co1/3Mn1/3O2-xSx using a novel plasma-enhanced doping strategy. The structure and electrochemical performance of LiNi1/3Co1/3Mn1/3O2-xSx are investigated systematically, which confirms that the S doping can make the structure stable and benefit the electrochemical performance. The phys

  8. Calorimetric measurements on Li{sub 4}C{sub 60} and Na{sub 4}C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Akira; Miyazaki, Yuji [Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Michałowski, Paweł P.; Gracia-Espino, Eduardo; Wågberg, Thomas, E-mail: Thomas.wagberg@physics.umu.se [Department of Physics, Umeå University, S-90187 Umeå (Sweden); Sundqvist, Bertil [Department of Physics, Umeå University, S-90187 Umeå (Sweden); State Key Laboratory for Superhard Materials, Jilin University, Changchun 130012 (China)

    2015-04-28

    We show specific heat data for Na{sub 4}C{sub 60} and Li{sub 4}C{sub 60} in the range 0.4-350 K for samples characterized by Raman spectroscopy and X-ray diffraction. At high temperatures, the two different polymer structures have very similar specific heats both in absolute values and in general trend. The specific heat data are compared with data for undoped polymeric and pristine C{sub 60}. At high temperatures, a difference in specific heat between the intercalated and undoped C{sub 60} polymers of 100 J K{sup −1} mol{sup −1} is observed, in agreement with the Dulong-Petit law. At low temperatures, the specific heat data for Li{sub 4}C{sub 60} and Na{sub 4}C{sub 60} are modified by the stiffening of vibrational and librational molecular motion induced by the polymer bonds. The covalent twin bonds in Li{sub 4}C{sub 60} affect these motions to a somewhat higher degree than the single intermolecular bonds in Na{sub 4}C{sub 60}. Below 1 K, the specific heats of both materials become linear in temperature, as expected from the effective dimensionality of the structure. The contribution to the total specific heat from the inserted metal ions can be well described by Einstein functions with T{sub E} = 386 K for Li{sub 4}C{sub 60} and T{sub E} = 120 K for Na{sub 4}C{sub 60}, but for both materials we also observe a Schottky-type contribution corresponding to a first approximation to a two-level system with ΔE = 9.3 meV for Li{sub 4}C{sub 60} and 3.1 meV for Na{sub 4}C{sub 60}, probably associated with jumps between closely spaced energy levels inside “octahedral-type” ionic sites. Static magnetic fields up to 9 T had very small effects on the specific heat below 10 K.

  9. Efficient plasma-enhanced method for layered LiNi1/3Co1/3Mn1/3O2 cathodes with sulfur atom-scale modification for superior-performance Li-ion batteries.

    Science.gov (United States)

    Jiang, Qianqian; Chen, Ning; Liu, Dongdong; Wang, Shuangyin; Zhang, Han

    2016-06-01

    In order to improve the electrochemical performance of LiNi1/3Co1/3Mn1/3O2 as a lithium insertion positive electrode material, atom-scale modification was realized to obtain the layered oxysulfide LiNi1/3Co1/3Mn1/3O2-xSx using a novel plasma-enhanced doping strategy. The structure and electrochemical performance of LiNi1/3Co1/3Mn1/3O2-xSx are investigated systematically, which confirms that the S doping can make the structure stable and benefit the electrochemical performance. The phys-chemical characterizations indicate that oxygen atoms in the initial LiNi1/3Co1/3Mn1/3O2 have been partially replaced by S atoms. It should be pointed out that the atom-scale modification does not significantly alter the intrinsic structure of the cathode. Compared to the pristine material, the LiNi1/3Co1/3Mn1/3O2-xSx shows a superior performance with a higher capacity (200.4 mA h g(-1)) and a significantly improved cycling stability (maintaining 94.46% of its initial discharge capacity after 100 cycles). Moreover, it has an excellent rate performance especially at elevated performance, which is probably due to the faster Li(+) transportation after S doping into the layered structure. All the results show that the atom-scale modification with sulfur atoms on LiNi1/3Co1/3Mn1/3O2, which significantly improved the electrochemical performance, offers a novel anionic doping strategy to realize the atom-scale modification of electrode materials to improve their electrochemical performance. PMID:27189799

  10. Atomic/Molecular Layer Deposition of Lithium Terephthalate Thin Films as High Rate Capability Li-Ion Battery Anodes.

    Science.gov (United States)

    Nisula, Mikko; Karppinen, Maarit

    2016-02-10

    We demonstrate the fabrication of high-quality electrochemically active organic lithium electrode thin films by the currently strongly emerging combined atomic/molecular layer deposition (ALD/MLD) technique using lithium terephthalate, a recently found anode material for lithium-ion battery (LIB), as a proof-of-the-concept material. Our deposition process for Li-terephthalate is shown to well comply with the basic principles of ALD-type growth including the sequential self-saturated surface reactions, a necessity when aiming at micro-LIB devices with three-dimensional architectures. The as-deposited films are found crystalline across the deposition temperature range of 200-280 °C, which is a trait highly desired for an electrode material but rather unusual for hybrid inorganic-organic thin films. Excellent rate capability is ascertained for the Li-terephthalate films with no conductive additives required. The electrode performance can be further enhanced by depositing a thin protective LiPON solid-state electrolyte layer on top of Li-terephthalate; this yields highly stable structures with capacity retention of over 97% after 200 charge/discharge cycles at 3.2 C. PMID:26812433

  11. Unusual phase behavior in the piezoelectric perovskite system, Li(x)Na(1-x)NbO3.

    Science.gov (United States)

    Peel, Martin D; Ashbrook, Sharon E; Lightfoot, Philip

    2013-08-01

    The system Li(x)Na(1-x)NbO3 has been studied by using a combination of X-ray and neutron powder diffraction and (23)Na solid-state NMR spectroscopy. For x = 0.05 we confirm a single polar orthorhombic phase. For 0.08 ≤ x ≤ 0.20 phase mixtures of this orthorhombic phase, together with a rhombohedral phase, isostructural with the low-temperature ferroelectric polymorph of NaNbO3, are observed. The relative fractions of these two phases are shown to be critically dependent on synthetic conditions: the rhombohedral phase is favored by higher annealing temperatures and rapid cooling. We also observe that the orthorhombic phase transforms slowly to the rhombohedral phase on standing in air at ambient temperature. For 0.25 ≤ x ≤ 0.90 two rhombohedral phases coexist, one Na-rich and the other Li-rich. In this region the phase behavior is independent of reaction conditions. PMID:23855830

  12. Calculation of inelastic helium atom scattering from H2/ NaCl(001)

    DEFF Research Database (Denmark)

    Bruch, L.W.; Hansen, Flemming Yssing; Traeger, F.

    2011-01-01

    The one-phonon inelastic low energy helium atom scattering theory is adapted to cases where the target monolayer is a p(1 × 1) commensurate square lattice. Experimental data for para-H2/NaCl(001) are re-analyzed and the relative intensities of energy loss peaks in the range 6 to 9 meV are determi...

  13. X-ray diffraction analysis of LiCu{sub 2}O{sub 2} crystals with additives of silver atoms

    Energy Technology Data Exchange (ETDEWEB)

    Sirotinkin, V. P., E-mail: irotinkin.vladimir@mail.ru; Bush, A. A.; Kamentsev, K. E. [Moscow State Technical University of Radio Engineering, Electronics, and Automation (Russian Federation); Dau, H. S. [People’s Friendship University of Russia (Russian Federation); Yakovlev, K. A. [Moscow State Technical University of Radio Engineering, Electronics, and Automation (Russian Federation); Tishchenko, E. A. [People’s Friendship University of Russia (Russian Federation)

    2015-09-15

    Silver-containing LiCu{sub 2}O{sub 2} crystals up to 4 × 8 × 8 mm in size were grown by the crystallization of 80(1-x)CuO · 20{sub x}AgNO{sub 3} · 20Li{sub 2}CO{sub 3} (0 ≤ x ≤ 0.5) mixture melt. According to the X-ray spectral and Rietveld X-ray diffraction data, the maximum amount of silver incorporated in the LiCu{sub 2}O{sub 2} structure is about 4 at % relative to the copper content. It was established that silver atoms occupy statistically crystallographic positions of lithium atoms. The incorporation of silver atoms is accompanied by a noticeable increase in parameter c of the LiCu{sub 2}O{sub 2} rhombic unit cell, a slight increase in parameter a, and a slight decrease in parameter b.

  14. In situ diffusion measurements in solids using short-lived radioactive tracers of {sup 8}Li and {sup 20}Na

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, HIronobu, E-mail: hironobu.ishiyama@kek.jp [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Jeong, S.C.; Watanabe, Y.X.; Hirayama, Y.; Imai, N.; Miyatake, H.; Oyaizu, M.; Katayama, I. [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Sataka, M.; Osa, A.; Otokawa, Y.; Matsuda, M.; Makii, H.; Nishio, K.; Sato, T.K. [Japan Atomic Energy Agency (JAEA), 2-4 Shirane, Tokai, Ibaraki 319-1195 (Japan); Nakao, A. [Nishina Accelerator-based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0839 (Japan)

    2013-12-15

    We are developing in situ diffusion measurements in solids using short-lived radioactive ion beams provided from an isotope separator on-line (ISOL). We examined the feasibility of a new in situ nanoscale diffusion measurement method using a radioactive {sup 8}Li tracer by computer simulations. Under moderate experimental conditions, we have found that the detection limit of lithium diffusion coefficient can be improved to a low value of 1×10{sup -12}cm{sup 2}/s. Also, in situ sodium diffusion measurement in Na battery materials can be applicable using a radioactive {sup 20}Na tracer. We found Na diffusion coefficients can be measured, ranging from 10{sup -6} to 10{sup -10}cm{sup 2}/s by computer simulations.

  15. Experimental studies on interactions of molten LiF-NaF salt with some candidate structural materials for components of advanced nuclear reactors

    International Nuclear Information System (INIS)

    Interaction of molten 60 LiF - 40 NaF (% mol) salt with candidate structural materials for components of advanced nuclear reactors has been studied using electron probe microanalysis (EPMA) and inductively coupled plasma atomic emission spectrometry (ICP-OES). The corrosion of structural materials (stainless steel, Ni base alloy, nickel), which was induced by the molten salt melt, has been examined in dependence on the time of exposure at operating temperature of 680 deg C. The above choice of the two analytical techniques made it possible to assess on the whole the extent of corrosion. The corrosion phenomena in structural materials were investigated using EPMA. Corrosion-released elements dissolved in solidified molten salt were determined after salt dissolution by means of ICP-OES. The LiF-NaF melt produced corrosion, which proved as a surficial modification of a structural material and a trace contamination of the melt itself. The X-ray maps by EPMA with its 1-μm lateral resolution revealed compositional changes in structural materials, such as, e. g. regular depletion of Cr in alloy A686 to the depth of 10 - 25 μm. While the lateral resolution of LA-ICP-MS with the applied laser spot diameter of 25 μm was not exactly adequate to mapping of the corroded material section and, consequently, yielded less information in comparison with EPMA, this technique was quite sufficient for the mapping of elemental content changes in solidified salt profile. Finally, nickel was proved to be the most resistant material. It was concluded that: (i) EPMA study, involving semi-quantitative elemental mapping / content profiling and detailed spot quantitative analyses makes it possible to obtain quantitative assessment of the corrosion process; (ii) qualitative profiles are provided by LA-ICP-MS, which needs further development on quantification procedure based on matched calibration samples. (author)

  16. A comparative study of the different sample decomposition procedures for three common lithium minerals: a scheme for the accurate elemental analysis of Li, Na, K, Rb, Cs, Mg, Ca, Mn, Al, Fe, and Ti using FAAS and ICP-AES

    International Nuclear Information System (INIS)

    An attempt is made for analysis of elemental composition of lithium minerals of standard samples (NBS) available in the laboratory and few samples of lithium minerals collected from field areas of southern region, Bangalore. Common lithium minerals are spodumene, petalite and lepidolite and Li2O values ranges from 4% to 8%. Lithium is considered as one of the important source for fusion technology and having accurate determination of lithium and associated elements viz. Na, K, Rb, Cs, Mg etc may be useful in atomic energy. Literature survey indicates that there is no well defined methodology documented for the elemental characterization of spodumene, lepidolite and petalite using FAAS and ICP-AES

  17. Spontaneous doping of two-dimensional NaCl films with Cr atoms: aggregation and electronic structure

    OpenAIRE

    Li, Zhe; Hsin-Yi Tiffany, Chen; Schouteden, Koen; Janssens, Ewald; Van Haesendonck, Chris; Lievens, Peter; Pacchioni, Gianfranco

    2015-01-01

    Scanning tunneling microscopy (STM) experiments combined with density functional theory (DFT) calculations reveal that deposited Cr atoms replace either Na or Cl ions, forming substituting dopants in ultrathin NaCl/Au(111) films. The Cr dopants exchange electrons with the support thus changing the electronic properties of the film and in particular the work function. The Cr atoms spontaneously aggregate near the edges of the bilayer (2L) NaCl islands, forming a new phase in the insulator with...

  18. Adsorption/desorption kinetics of Na atoms on reconstructed Si (111)-7 x 7 surface

    International Nuclear Information System (INIS)

    Self-assembled nanostructures on a periodic template are fundamentally and technologically important as they put forward the possibility to fabricate and pattern micro/nano-electronics for sensors, ultra high-density memories and nanocatalysts. Alkali-metal (AM) nanostructure grown on a semiconductor surface has received considerable attention because of their simple hydrogen like electronic structure. However, little efforts have been made to understand the fundamental aspects of the growth mechanism of self-assembled nanostructures of AM on semiconductor surfaces. In this paper, we report organized investigation of kinetically controlled room-temperature (RT) adsorption/desorption of sodium (Na) metal atoms on clean reconstructed Si (111)-7 x 7 surface, by X-ray photoelectron spectroscopy (XPS). The RT uptake curve shows a layer-by-layer growth (Frank-vander Merve growth) mode of Na on Si (111)-7 x 7 surfaces and a shift is observed in the binding energy position of Na (1s) spectra. The thermal stability of the Na/Si (111) system was inspected by annealing the system to higher substrate temperatures. Within a temperature range from RT to 350 oC, the temperature induced mobility to the excess Na atoms sitting on top of the bilayer, allowing to arrange themselves. Na atoms desorbed over a wide temperature range of 370 oC, before depleting the Si (111) surface at temperature 720 oC. The acquired valence-band (VB) spectra during Na growth revealed the development of new electronic-states near the Fermi level and desorption leads the termination of these. For Na adsorption up to 2 monolayers, decrease in work function (-1.35 eV) was observed, whereas work function of the system monotonically increases with Na desorption from the Si surface as observed by other studies also. This kinetic and thermodynamic study of Na adsorbed Si (111)-7 x 7 system can be utilized in fabrication of sensors used in night vision devices.

  19. Versatile Coordination Mode of LiNaB8O13 and α- and β-LiKB8O13 via the Flexible Assembly of Four-Connected B5O10 and B3O7 Groups.

    Science.gov (United States)

    An, Donghai; Kong, Qingrong; Zhang, Min; Yang, Yun; Li, Danni; Yang, Zhihua; Pan, Shilie; Chen, Huimin; Su, Zhi; Sun, Yi; Mutailipu, Miriding

    2016-01-19

    Three new alkali-metal mixed borates, LiNaB8O13, α-LiKB8O13, and β-LiKB8O13, containing a (3)∞[B8O13] three-dimensional network have been successfully synthesized. Their fundamental building block is [B8O16](8-) formed by the vertex-sharing [B5O10](5-) and [B3O7](5-) groups, which are topologically identical when they are considered as four-connected nodes. The viewpoints give us a feasible way to investigate the versatile structure assembly of borates with a complex network. PMID:26692328

  20. Hydrogen storage of type MBH{sub 4}(H{sub 2})n M = Li, Na, K, Rb, Cs; Almacenadores de hidrogeno del tipo MBH{sub 4}(H{sub 2})n M = Li, Na, K, Rb, Cs

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Castro, Maria Esther [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)] e-mail: esther.sanchez@cinvestav.edu.mx; Sanchez-Vazquez, Mario [Centro de Investigacion en Materiales Avanzados, S.C., Apodaca, Nuevo Leon (Mexico)

    2009-09-15

    Interest has recently been increasing in finding new sources of energy other than fossil fuels. Hydrogen has potential with respect to oil, it does not contaminate the environment or produce greenhouse gases. Nevertheless, finding materials capable of storing hydrogen is not trivial, since certain aspects must be addressed, such as reversible hydrogen storage with high gravimetric and volumetric density, manipulated at moderate temperatures and pressures. To contribute to the search for new materials, we are interested in studying the structures of type MBH{sub 4}, which have a boron atom and a M metal. The boron has a lighter mass and is surrounded by four hydrogen atoms. LiBH{sub 4}, for example, is already being used as a source of hydrogen by disassociating the B-H bonds. On the other hand, the M atom is positive and can house molecular hydrogen in its coordination sphere. Our studies, using mp{sup 2}/def2-TZVP computational methods, show that this type of structures (MBH4) can coordinate in the M atom from three (when M = Li) to nine (when M = Cs) hydrogen molecules. [Spanish] Recientemente, el interes por encontrar nuevas fuentes de energia diferentes al combustible fosil ha ido en aumento. El hidrogeno tiene un potencial con respecto al petroleo, no contamina el medio ambiente ni produce gases invernadero. Sin embargo, encontrar materiales capaces de almacenar hidrogeno no es trivial, ya que se deben cuidar aspectos como: almacenar reversiblemente hidrogeno con alta densidad gravimetrica y volumetrica, y manipularlos a temperaturas y presiones moderadas. A fin de contribuir con la busqueda de nuevos materiales, es de nuestro interes estudiar a las estructuras del tipo MBH4. Estas estructuras tienen la caracteristica de tener un atomo de boro y un metal M. El boro es de masa ligera y esta rodeado de cuatro atomos de hidrogeno. El LiBH{sub 4} por ejemplo ya se esta utilizando como fuente de hidrogenos al disociar los enlaces B-H. Por otra parte, el atomo M es

  1. Conductivity of p(AAc) Cryogel and Its Li+, Na+, and K+ Salts for NH3 Sensing

    Science.gov (United States)

    Sahiner, Nurettin; Demirci, Sahin; Sel, Kivanc

    2016-04-01

    Poly(acrylic acid) [p(AAc)] cryogel has been synthesized by a cryopolymerization technique under cryogenic conditions. The synthesized p(AAc) cryogel was treated with LiOH, NaOH, and KOH to generate corresponding salt forms of carboxylic acid groups within the p(AAc) cryogel network for activation as p(AAc)-Li+, p(AAc)-Na+, and p(AAc)-K+, respectively. The synthesized p(AAc)-based cryogels were characterized via Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The room-temperature electrical conductivity of the p(AAc), p(AAc)-Li+, p(AAc)-Na+, and p(AAc)-K+ cryogels was measured as 10-11 S cm-1, 10-10 S cm-1, 10-9 S cm-1, and 10-8 S cm-1, respectively. Furthermore, the p(AAc) cryogel and its salt forms were tested as sensor materials for NH3 gas by exposing them to NH3 vapor for 60 min under ambient conditions. Upon exposure to NH3 vapor, it was found that the conductivity of the bare p(AAc) and p(AAc)-K+ cryogels increased by up to 105- and 102-fold, respectively, compared with their NH3 unexposed states. The increase in conductivity for the other salt forms of p(AAc) cryogel was about 60-fold compared with their bare form. The conductivity increase for the p(AAc) and p(AAc)-K+ cryogels was therefore further investigated by changing the NH3 vapor exposure time, revealing that these materials could be used as sensors for NH3. It was further found that a 5 min NH3 gas exposure time was sufficient for p(AAc)-K+ cryogel to generate a detectable response via a change in the conductivity of the matrix.

  2. Viscosity of LiF–NaF–KF eutectic and effect of cerium trifluoride and uranium tetrafluoride additions

    International Nuclear Information System (INIS)

    Highlights: • Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) is measured. • Method of torsional oscillations damping of a cylinder filled with the melt is used. • Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. • Addition of CeF3 or UF4 significantly increased the liquidus temperature of eutectic. • Addition of CeF3 and UF4 decreased the viscosity of the eutectic at low temperatures. - Abstract: Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) has been measured in the temperature range 727–1144 K by the method of torsional oscillations damping of a cylinder with the liquid under study. Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. The volume fraction of the clusters in the eutectic as a function of its temperature was estimated. The kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (in mol%) with additions of (1) 5 and 10 mol% CeF3 as well as (2) 20 mol% UF4 and 10 mol% CeF3 was also measured. It is experimentally proved that the addition of 5 mol% CeF3 significantly reduces the viscosity at low temperatures and slightly increases it – at high temperatures. Reduction of viscosity at low temperatures can be explained by the fact that the molecules of CeF3 destroy clusters. Additions of 20 mol% UF4 also decreased kinematic viscosity of the molten salt mixture compared to pure 46.5LiF–11.5NaF–42KF eutectic (in mol%). Note, that all additions used significantly increased the liquidus temperature of the molten salt mixture. Particularly, additions of 20 mol% UF4 without and with 10 mol% CeF3 increased the liquidus temperature up to 923 and 1023 K, respectively

  3. Viscosity of LiF–NaF–KF eutectic and effect of cerium trifluoride and uranium tetrafluoride additions

    Energy Technology Data Exchange (ETDEWEB)

    Merzlyakov, Alexander; Ignatiev, Victor, E-mail: Ignatev_VV@nrcki.ru; Abalin, Sergei

    2014-10-15

    Highlights: • Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) is measured. • Method of torsional oscillations damping of a cylinder filled with the melt is used. • Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. • Addition of CeF{sub 3} or UF{sub 4} significantly increased the liquidus temperature of eutectic. • Addition of CeF{sub 3} and UF{sub 4} decreased the viscosity of the eutectic at low temperatures. - Abstract: Kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (mol%) has been measured in the temperature range 727–1144 K by the method of torsional oscillations damping of a cylinder with the liquid under study. Found that the kinematic viscosity of this eutectic has some deviations from the exponential law, that may be explained by the existence of clusters in the melt. The volume fraction of the clusters in the eutectic as a function of its temperature was estimated. The kinematic viscosity of the 46.5LiF–11.5NaF–42KF eutectic (in mol%) with additions of (1) 5 and 10 mol% CeF{sub 3} as well as (2) 20 mol% UF{sub 4} and 10 mol% CeF{sub 3} was also measured. It is experimentally proved that the addition of 5 mol% CeF{sub 3} significantly reduces the viscosity at low temperatures and slightly increases it – at high temperatures. Reduction of viscosity at low temperatures can be explained by the fact that the molecules of CeF{sub 3} destroy clusters. Additions of 20 mol% UF{sub 4} also decreased kinematic viscosity of the molten salt mixture compared to pure 46.5LiF–11.5NaF–42KF eutectic (in mol%). Note, that all additions used significantly increased the liquidus temperature of the molten salt mixture. Particularly, additions of 20 mol% UF{sub 4} without and with 10 mol% CeF{sub 3} increased the liquidus temperature up to 923 and 1023 K, respectively.

  4. Optimization and Calculation of TbCl3-ACl (A=Li, Na, K, Rb, Cs) Phase Diagrams

    Institute of Scientific and Technical Information of China (English)

    Sun Yimin; Zhang Jing; Guan Mingyun; Qiao Zhiyu

    2005-01-01

    By using CALPHAD (Calculation of Phase Diagram) technique the optimization and calculation of the binary systems of TbCl3-ACl (A= Li, Na, K, Rb, Cs) were carried out. For describing the Gibbs free energy of liquid phase in these systems the new modified quasichemical model in the pair-approximation for short-range ordering was used. From measured phase equilibria data and experimental integral properties the TbCl3-ACl phase diagrams were optimized and calculated. A set of thermodynamic functions was optimized based on an interactive computer-assisted analysis. The calculated phase diagrams and thermodynamic data are self-consistent.

  5. A first principles study of structural stability, electronic structure and mechanical properties of ABeH3 (A = Li, Na)

    International Nuclear Information System (INIS)

    Ab initio calculations are performed to investigate the structural stability, electronic structure and mechanical properties of ABeH3 (A = Li, Na) for three different crystal structures, namely orthorhombic (Pnma), monoclinic (P21/c) and triclinic (P-1) phase. Among the considered structures monoclinic (P21/c) phase is found to be the most stable one for all the three hydrides at ambient condition. The electronic structure reveals that these materials are wide band gap semiconductors. The calculated elastic constants indicate that these materials are mechanically stable at ambient condition

  6. Rotationally inelastic collisions of LiH with He: Quasiclassical dynamics of atom-rigid rotor trajectories

    International Nuclear Information System (INIS)

    Rotationally inelastic cross sections for the LiH--He collision system are computed classically using a previously derived ab initio potential energy surface [D. M. Silver, J. Chem. Phys. 72, 6445 (1980)]. The LiH is in its ground vibronic state and is initially taken to be in its j = 1 rotational state. The He is in its ground electronic state. The system is treated as an atom-rigid rotor interaction. The results are compared with previously computed cross sections derived from the same ab initio potential energy surface using the coupled states approximation for quantum mechanical scattering [E. F. Jendrek and M. H. Alexander, J. Chem. Phys. 72, 6452 (1980)]. The theoretical total cross sections are averaged over a temperature distribution and are then compared with experimental measurements of corresponding cross sections for a rotationally resolved LiH beam ( j = 1) incident on a He gas target in thermal equilibrium at room temperature [P. J. Dagdigian and B. E. Wilcomb, J. Chem. Phys. 72, 6462 (1980)]. The agreement between classical, quantum and experimental results is discussed

  7. Characterization of charge-exchange collisions between ultracold $\\rm{^6Li}$ atoms and $\\rm{^{40}Ca^+}$ ions

    CERN Document Server

    Saito, R; Sasakawa, M; Nakai, R; Raoult, M; Silva, H Da; Dulieu, O; Mukaiyama, T

    2016-01-01

    We investigate the energy dependence and the internal-state dependence of the charge-exchange collision cross sections in a mixture of $^6$Li atoms and $^{40}$Ca$^+$ ions in the collision energy range from 0.2 mK to 1 K. Deliberately excited ion micromotion is used to control the collision energy of atoms and ions. The energy dependence of the charge-exchange collision cross section obeys the Langevin model in the temperature range of the current experiment, and the measured magnitude of the cross section is correlated to the internal state of the $^{40}$Ca$^+$ ions. Revealing the relationship between the charge-exchange collision cross sections and the interaction potentials is an important step toward the realization of the full quantum control of the chemical reactions at an ultralow temperature regime.

  8. Confocal and Atomic Force Microscopies of Color Centers Produced by Ultrashort Laser Irradiation in LiF Crystals

    Science.gov (United States)

    Courrol, Lilia Coronato; Martinez, Oscar; Samad, Ricardo Elgul; Gomes, Laércio; Ranieri, Izilda Márcia; Baldochi, Sonia Licia; de Freitas, Anderson Zanardi; Junior, Nilson Dias Vieira

    2008-04-01

    We report properties of the spatial and spectral distribution of color centers produced in LiF single crystals by ultrashort high intensity laser pulses (60 fs, 10 GW) using confocal spectral microscopy and atomic force microscopy. We could identify a large amount of F centers that gave rise to aggregates such as F2, F4, F2+ and F3+ distributed in cracked shape brownish areas. We have taken a 3D image using confocal microscopy of the sample (luminescent image) and no difference is observed in the different planes. The atomic force microscopy image clearly shows the presence of defects on the modified surface. The formation of micrometer or sub-micrometer voids, filaments and void strings was observed and related to filamentation process.

  9. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    Energy Technology Data Exchange (ETDEWEB)

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  10. Utječe li bračno stanje na doživljeni stres i mentalnu čvrstoću kod studenata sestrinstva i kriminalistike?

    OpenAIRE

    Puljizević, Nikolina; Miloslavić, Tihana; Perinić-Lewis, Ana; Novokmet, Natalija; Havaš Auguštin, Dubravka; Sindik, Joško

    2014-01-01

    Cilj: Zanimanje medicinske sestre / medicinskog tehničara i zanimanje kriminalista izrazito su specifična i podložna visokoj razini stresa na radnom mjestu. Zanimljivo je kako se studenti uz rad na preddiplomskom stručnom studiju Sestrinstva Sveučilišta u Dubrovniku i studenti diplomskog specijalističkog stručnog studija kriminalistike na Visokoj policijskoj školi u Zagrebu nose sa svakodnevnim stresom. Cilj istraživanja bio je utvrditi postoje li razlike u dvama aspektima doživljenog stre...

  11. First principles study of hydrogen storage material NaBH4 and LiAlH4 compounds: electronic structure and optical properties

    Science.gov (United States)

    Ghellab, T.; Charifi, Z.; Baaziz, H.; Uğur, Ş.; Uğur, G.; Soyalp, F.

    2016-04-01

    A comprehensive study of structure, phase stability, optical and electronic properties of LiAlH4 and NaBH4 light-metal hydrides is presented. The calculations are carried out within density functional theory using the full potential linear augmented plane wave method. The exchange-correlation potential is treated within the local density approximation and the generalized gradient approximation (GGA) to calculate the total energy. Furthermore, the Engel-Vosko GGA approach is employed to compute electronic and optical properties such as reflectivity spectra. The phases α, β and γ of LiAlH4 and NaBH4 hydrides are investigated, the phase transition from the β to the high-pressure γ phase is determined for NaBH4 and is accompanied by a 1% volume decrease. For LiAlH4, no phase transition is detected. The materials under consideration are classified as wide band gap compounds. From the analysis of the structures at different phases, it is deduced that the hydrides show strong covalent interaction between B (Al) and H in the [BH4]- ([AlH4]-) anions and ionic bonding character between [BH4]- and Na+ for NaBH4, and [AlH4]- and Li+ for LiAlH4. The complex dielectric function, absorption coefficient and the reflectivity spectra are also computed and analyzed in different phases.

  12. Structural phase stability, electronic structure and mechanical properties of alkali metal hydrides AMH4 (A=Li, Na; M=B, AL)

    Science.gov (United States)

    Santhosh, M.; Rajeswarapalanichamy, R.

    2016-01-01

    The structural stability of Alkali metal hydrides AMH4 (A=Li, Na; M=B, Al) is analyzed among the various crystal structures, namely hexagonal (P63mc), tetragonal (P42/nmc), tetragonal (P-421c), tetragonal (I41/a), orthorhombic (Pnma) and monoclinic (P21/c). It is observed that, orthorhombic (Pnma) phase is the most stable structure for LiBH4, monoclinic (P21/c) for LiAlH4, tetragonal (P42/nmc) for NaBH4 and tetragonal (I41/a) for NaAlH4 at normal pressure. Pressure induced structural phase transitions are observed in LiBH4, LiAlH4, NaBH4 and NaAlH4 at the pressures of 4 GPa, 36.1 GPa, 26.5 GPa and 46 GPa respectively. The electronic structure reveals that these metal hydrides are wide band gap insulators. The calculated elastic constants indicate that these metal hydrides are mechanically stable at normal pressure.

  13. Hydrogen storage in LiH: A first principle study

    Science.gov (United States)

    Banger, Suman; Nayak, Vikas; Verma, U. P.

    2014-04-01

    First principles calculations have been performed on the Lithium hydride (LiH) using the full potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory. We have extended our calculations for LiH+2H and LiH+6H in NaCl structure. The structural stability of three compounds have been studied. It is found that LiH with 6 added Hydrogen atoms is most stable. The obtained results for LiH are in good agreement with reported experimental data. Electronic structures of three compounds are also studied. Out of three the energy band gap in LiH is ˜3.0 eV and LiH+2H and LiH+6H are metallic.

  14. Direct Growth of Bismuth Film as Anode for Aqueous Rechargeable Batteries in LiOH, NaOH and KOH Electrolytes

    OpenAIRE

    Wenhua Zuo; Pan Xu; Yuanyuan Li; Jinping Liu

    2015-01-01

    As promising candidates for next-generation energy storage devices, aqueous rechargeable batteries are safer and cheaper than organic Li ion batteries. But due to the narrow voltage window of aqueous electrolytes, proper anode materials with low redox potential and high capacity are quite rare. In this work, bismuth electrode film was directly grown by a facile hydrothermal route and tested in LiOH, NaOH and KOH electrolytes. With low redox potential (reduction/oxidation potentials at ca. −0....

  15. Elastic Scattering between Ultracold 23Na and 85Rb Atoms in the Triplet State

    Institute of Scientific and Technical Information of China (English)

    HU Qiu-Bo; ZHANG Yong-Sheng; SUN Jin-Feng; YU Ke

    2011-01-01

    @@ The elastic scattering Properties between ultracold 23Na and 85Rd atoms for the triplet state(a3∑u+ )are researched.The s-wave scattering lengts of 23Na and 85Rb are calculate by the Numerov ana semtc asstc method with two kinds of interatomic potentials, which are the interpolation potential and Lennard-Jones potential(LJ12,6)by the same phase 4φ Shape resonances appear clearly in the l= 5 partial waves for the a- Lu state.Moreover, the s-wave scattering cross section, total cross section and energy positions of shape resonances are also discussed.%The elastic scattering properties between ultracold 23Na and 85 Rb atoms for the triplet state (a3Σu+ ) are researched. The s-wave scattering lengths of 23Na and 85Rb are calculated by the Numerov and semiclassical method with two kinds of interatomic potentials, which are the interpolation potential and Lennard-Jones potential (LJ12,6) by the same phase φ. Shape resonances appear clearly in the l= 5 partial waves for the a3 Σu+state. Moreover, the s-wave scattering cross section, total cross section and energy positions of shape resonances are also discussed.

  16. Effects of alkaline cations (M+ = Li+, Na+, K+, Cs+) on the electrochemical synthesis of polyaniline in nitric acid electrolyte

    Institute of Scientific and Technical Information of China (English)

    WU Kezhong; WANG Xindong; MENG Xu

    2005-01-01

    The effects of alkaline cations (M+ = Li+, Na+, K+, Cs+) on the electrochemical synthesis of polyaniline were cartied out under cyclovoltammetric conditions using nitrates of Li+, Na+, K+, and Cs+ as the supporting electrolytes. The results show that the oxidation potentials of aniline in the electrolytes decrease as the protonation extent of aniline decreases from the first scan, which is caused by the decrease of the ionic radius of alkaline metal ions at the same concentration of alkaline cations. With the scan number increasing, the deposit charge Q as the characteristic growth function also depends on the protonation of aniline, and it increases with the ionic radius of alkaline cations increasing. SEM images show the effect of alkaline cations on the morphology of polyaniline. It is clear that the ionic mobility of alkaline cations is further lower than that of H+. Alkaline cations and counter-ions were the species responsible for the enhancement of Pani electrosynthesis. Therefore, this is exactly what SEM images show: a relatively rough fibrous structure in the case of Pani-H+ suggesting a sponge-like structure and a highly orderly fiber-like structure in the case of Pani-M+.

  17. Efeito da adição de Na2O na viscosidade e devitrificação do vidro obtido a partir de cinzas volantes e Li2O Influence of Na2O on the viscosity and devitrification behavior of glasses obtained from fly ashes and Li2O

    Directory of Open Access Journals (Sweden)

    Etney Neves

    1998-07-01

    Full Text Available Glass-ceramic materials can be produced by the addition of LiO2 to fly ashes disposible in Southern Brazil. These glass-ceramics are based on the Al2O3-SiO2-Li 2O system. The high viscosity of the obtained glasses, however, makes forming useful articles with these materials difficult. In this study we investigate the effect of adding low cost Na2CO3 on the melt viscosity and on the nature of the developed crystalline phases. It was intended that the ultimate crystalline phase (LiAlSi3O8 should not be altered. With additions up to 3 wt. % Na2CO3, the viscosity was apparently lowered and no new crystalline phase were detected.

  18. Međufazna sinteza FePO4 različitih morfologija i utjecaj morfologije na elektrokemijska svojstva LiFePO4/C

    OpenAIRE

    Luo, Y.-H.; He, N.; Wang, Y.-C.; Cao, W.-G.; Feng, P.

    2015-01-01

    U ovom je radu korištena metoda međufazne sinteze za pripravu FePO4 različitih morfologija te je istraživan učinak morfologije na pripravu i elektrokemijska svojstva LiFePO4/C. Rezultati su pokazali da je FePO4 pri temperaturi obrade 30 °C amorfan, a pri 80 °C monoklinski. LiFePO4/C je pripravljen iz dvaju prekursora oblika polukružne šupljine s kristalnom strukturom olivina. LiFePO4/C proizveden iz monoklinski strukturiranog prekursora pokazao je sitniju morfologiju i bolja elektrokemijska s...

  19. Comparative and complementary characterization of precipitate microstructures in Al-Mg-Si(-Li) alloys by transmission electron microscopy, energy dispersive X-ray spectroscopy and atom probe tomography

    International Nuclear Information System (INIS)

    Highlights: • Microalloying addition of Li enhances the age-hardening response of Al-Mg-Si alloys. • Size and number density of nanoclusters or precipitates are increased by Li addition. • Mg and Si contents within the aggregates are inversely decreased by Li addition. • Microalloying Li accelerates heterogeneous nucleation of such Mg-Si aggregates. - Abstract: In this study, comparative and complementary characterization of precipitate microstructures by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and atom probe tomography (APT) has been performed for Al-0.55 wt%Mg-0.89 wt%Si(-0.043 wt%Li) alloys aged at 433 K for 1.2 ks (under aging) and 36 ks (peak aging). Quantitative estimation of nanometer-scale clusters (nanoclusters) and β″ precipitates by TEM and APT revealed that microalloying addition of Li increases the size and number density of these Mg-Si aggregates, resulting in the enhanced age-hardening response. Positive evidence by APT for the segregation of Li suggests that heterogeneous nucleation of such Mg-Si aggregates with the aid of Li is attributed to the modified precipitate microstructures and thus improved mechanical strength of this alloy system

  20. Comparative and complementary characterization of precipitate microstructures in Al-Mg-Si(-Li) alloys by transmission electron microscopy, energy dispersive X-ray spectroscopy and atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Koshino, Yuki [Department of Mechanical Engineering and Materials Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Kozuka, Masaya [Materials Research Laboratory, Kobe Steel, Ltd., 1-5-5 Takatsukadai, Nishi-ku, Kobe 651-2271 (Japan); Hirosawa, Shoichi, E-mail: hirosawa@ynu.ac.jp [Department of Mechanical Engineering and Materials Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Aruga, Yasuhiro [Materials Research Laboratory, Kobe Steel, Ltd., 1-5-5 Takatsukadai, Nishi-ku, Kobe 651-2271 (Japan)

    2015-02-15

    Highlights: • Microalloying addition of Li enhances the age-hardening response of Al-Mg-Si alloys. • Size and number density of nanoclusters or precipitates are increased by Li addition. • Mg and Si contents within the aggregates are inversely decreased by Li addition. • Microalloying Li accelerates heterogeneous nucleation of such Mg-Si aggregates. - Abstract: In this study, comparative and complementary characterization of precipitate microstructures by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and atom probe tomography (APT) has been performed for Al-0.55 wt%Mg-0.89 wt%Si(-0.043 wt%Li) alloys aged at 433 K for 1.2 ks (under aging) and 36 ks (peak aging). Quantitative estimation of nanometer-scale clusters (nanoclusters) and β″ precipitates by TEM and APT revealed that microalloying addition of Li increases the size and number density of these Mg-Si aggregates, resulting in the enhanced age-hardening response. Positive evidence by APT for the segregation of Li suggests that heterogeneous nucleation of such Mg-Si aggregates with the aid of Li is attributed to the modified precipitate microstructures and thus improved mechanical strength of this alloy system.

  1. Electron momentum spectroscopy and linear combination of atomic orbitals calculation of bulk Na sub 2 O

    CERN Document Server

    Mikajlo, E A; Ford, M J

    2003-01-01

    This paper presents an experimental measurement of the electronic structure of Na sub 2 O in the solid phase using electron momentum spectroscopy and compares the results with ab initio calculations performed within the linear combination of atomic orbitals (LCAO) approximation. While Hartree-Fock (HF) can reproduce elastic properties we find it overestimates splitting of the oxygen valence bands by around 30% and the width of the O 2p band by a factor of 2. Our experimental values are 15.85 +- 0.2 and 0.6 +- 0.2 eV for these two quantities, respectively. Density functional methods are significantly better, with the hybrid functional PBE0 predicting the oxygen bandgap to within the experimental error. PBE0 also gives the best estimate of the Na core level energies. In contrast, HF performs best for the splitting between the oxygen and sodium bands. Our experimental values of 32.85 +- 0.2 and 27.45 +- 0.2 eV for the Na 2p-Na 2s and O 2p-Na 2p splittings agree well with previous measurements. Distribution of el...

  2. Discrete Li-occupation versus pseudo-continuous Na-occupation and their relationship with structural change behaviors in Fe2(MoO4)3

    OpenAIRE

    Ji-Li Yue; Yong-Ning Zhou; Si-Qi Shi; Zulipiya Shadike; Xuan-Qi Huang; Jun Luo; Zhen-Zhong Yang; Hong Li; Lin Gu; Xiao-Qing Yang; Zheng-Wen Fu

    2015-01-01

    The key factors governing the single-phase or multi-phase structural change behaviors during the intercalation/deintercalation of guest ions have not been well studied and understood yet. Through systematic studies of orthorhombic Fe2(MoO4)3 electrode, two distinct guest ion occupation paths, namely discrete one for Li and pseudo-continuous one for Na, as well as their relationship with single-phase and two-phase modes for Na1 and Li1, respectively during the intercalation/deintercalation pro...

  3. Thermal analysis and phase diagrams of the LiF BiF3 e NaF BiF3 systems

    International Nuclear Information System (INIS)

    Investigations of the binary systems LiF-BiF3 and NaF-BiF3 were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF3) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF3 to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF3 were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF4, decomposes into LiF and a liquid phase. The NaF-BiF3 system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF3) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF4 was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF4, NaBiF4 and a solid solution of NaF and BiF3 called I. The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

  4. Quantum and Classical Molecular Dynamics of Ionic Liquid Electrolytes for Na/Li-based Batteries: Molecular Origins of the Conductivity Behavior.

    Science.gov (United States)

    Vicent-Luna, Jose Manuel; Ortiz-Roldan, Jose Manuel; Hamad, Said; Tena-Zaera, Ramon; Calero, Sofia; Anta, Juan Antonio

    2016-08-18

    Compositional effects on the charge-transport properties of electrolytes for batteries based on room-temperature ionic liquids (RTILs) are well-known. However, further understanding is required about the molecular origins of these effects, in particular regarding the replacement of Li by Na. In this work, we investigate the use of RTILs in batteries, by means of both classical molecular dynamics (MD), which provides information about structure and molecular transport, and ab initio molecular dynamics (AIMD), which provides information about structure. The focus has been placed on the effect of adding either Na(+) or Li(+) to 1-methyl-1-butyl-pyrrolidinium [C4 PYR](+) bis(trifluoromethanesulfonyl)imide [Tf2 N](-) . Radial distribution functions show excellent agreement between MD and AIMD, which ensures the validity of the force fields used in the MD. This is corroborated by the MD results for the density, the diffusion coefficients, and the total conductivity of the electrolytes, which reproduce remarkably well the experimental observations for all studied Na/Li concentrations. By extracting partial conductivities, it is demonstrated that the main contribution to the conductivity is that of [C4 PYR](+) and [Tf2 N](-) . However, addition of Na(+) /Li(+) , although not significant on its own, produces a dramatic decrease in the partial conductivities of the RTIL ions. The origin of this indirect effect can be traced to the modification of the microscopic structure of the liquid as observed from the radial distribution functions, owing to the formation of [Na(Tf2 N)n ]((n-1)-) and [Li(Tf2 N)n ]((n-1)-) clusters at high concentrations. This formation hinders the motion of the large ions, hence reducing the total conductivity. We demonstrate that this clustering effect is common to both Li and Na, showing that both ions behave in a similar manner at a microscopic level in spite of their distinct ionic radii. This is an interesting finding for extending Li-ion and Li

  5. A density functional theory study on size-dependent structures, stabilities, and electronic properties of bimetallic MnAgm (M=Na, Li; n + m ≤ 7) clusters

    International Nuclear Information System (INIS)

    The equilibrium geometries, relative stabilities, and electronic properties of MnAgm(M=Na, Li; n + m ≤ 7) as well as pure Agn, Nan, Lin (n ≤ 7) clusters are systematically investigated by means of the density functional theory. The optimized geometries reveal that for 2 ≤ n ≤ 7, there are significant similarities in geometry among pure Agn, Nan, and Lin clusters, and the transitions from planar to three-dimensional configurations occur at n = 7, 7, and 6, respectively. In contrast, the first three-dimensional (3D) structures are observed at n + m = 5 for both NanAgm and LinAgm clusters. When n + m ≥ 5, a striking feature is that the trigonal bipyramid becomes the main subunit of LinAgm. Furthermore, dramatic odd—even alternative behaviours are obtained in the fragmentation energies, second-order difference energies, highest occupied and lowest unoccupied molecular orbital energy gaps, and chemical hardness for both pure and doped clusters. The analytic results exhibit that clusters with an even electronic configuration (2, 4, 6) possess the weakest chemical reactivity and more enhanced stability. (atomic and molecular physics)

  6. Density functional investigation of metal encapsulated X-C12Si8 heterofullerene (X=Li+, Na+, K+, Be2+, Mg2+, Ca2+, Al3+, Ga3+)

    International Nuclear Information System (INIS)

    The stability and the possible application of our recently reported SiC heterofullerenes inspire the investigation of their further stabilization through ion encapsulation. The endohedral complexes X-C12Si8, where X=Li+, Na+, K+, Be2+, Mg2+, Ca2+, Al3+, and Ga3+, are probed at the MPWB1K/6-311G* and B3LYP/6-311G* levels of theory. The optimized geometries show the expanding or contracting capability of C12Si8 in order to accommodate metal ion guests. The inclusion energies indicate the stability of the complexes compared to the components. Meanwhile, the calculated binding energies show the stabilization of C12Si8 through the inclusion of Be2+, Mg2+, Al3+, and Ga3+. The host-guest interaction that is probed through NBO atomic charges supports the obtained results. This study refers to 'metal ion encapsulation' as a strategy for stabilization of SiC heterofullerenes.

  7. Charge-transfer energy in closed-shell ion-atom interactions. [for H and Li ions in He

    Science.gov (United States)

    Alvarez-Rizzatti, M.; Mason, E. A.

    1975-01-01

    The importance of charge-transfer energy in the interactions between closed-shell ions and atoms is investigated. Ab initio calculations on H(plus)-He and Li(plus)-He are used as a guide for the construction of approximate methods for the estimation of the charge-transfer energy for more complicated systems. For many alkali ion-rate gas systems the charge-transfer energy is comparable to the induction energy in the region of the potential minimum, although for doubly charged alkaline-earth ions in rare gases the induction energy always dominates. Surprisingly, an empirical combination of repulsion energy plus asymptotic induction energy plus asymptotic dispersion energy seems to give a fair representation of the total interaction, especially if the repulsion energy is parameterized, despite the omission of any explicit charge-transfer contribution. More refined interaction models should consider the charge-transfer energy contribution.

  8. Liquidus temperatures of Na3AlF6-AlF3-CaF2-KF-LiF-Al2O3 melts

    Directory of Open Access Journals (Sweden)

    Peng J.P.

    2014-01-01

    Full Text Available Temperatures for the primary crystallization of Na3AlF6-AlF3-CaF2-KF-LiF-Al2O3 system adopted in aluminum electrolysis process were determined by thermal analysis. An empirical equation was derived to describe the liquidus temperatures for the primary crystallization of this multicomponent electrolyte system: t/℃=1011 + 0.7w(AlF3 - 0.232w(AlF32 - 7.65w(Al2O3 + 0.523w(Al2O32 - 8.96w(LiF + 0.043w(LiF2 - 3.32w(KF - 0.12w(KF2 - 3.28w(CaF2 +0.037w(CaF22 + 0.091w(AlF3w(LiF + 0.074w(AlF3w(KF + 0.084w(AlF3w(CaF2 - 0.27w(Al2O3w(LiF, where w(AlF3 denotes the mass fraction of excess aluminum fluoride with respect to cryolite. While w(Al2O3 ranges from 2% to 4%, w(LiF, w(KF and w(CaF2 from 0 to 7%, and the molar ratio of NaF/AlF3 from 2.2 to 3.

  9. Ultrathin atomic layer deposited ZrO2 coating to enhance the electrochemical performance of Li4Ti5O12 as an anode material

    International Nuclear Information System (INIS)

    Atomic layer deposition (ALD) was used to deposit ZrO2 directly on Li4Ti5O12 electrode to improve its electrochemical performance. The thickness of the deposited ZrO2 was controlled by adjusting ALD cycles from 0 to 1, 2, 5, 10 and 50. The Li4Ti5O12 electrodes with and without ZrO2 coating were characterized by scanning electron microscope, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscope, cyclic voltammetry (CV) and galvanostatic charge-discharge test. The CV result indicated that ZrO2 coating with 2, 5 and 10 ALD cycles could effectively reduce the electrochemical polarization of the Li4Ti5O12 electrode. Charge-discharge test revealed that the Li4Ti5O12 electrodes with 1-, 2- and 5-cycle ZrO2 coating exhibited higher specific capacity, better cycling performance and rate capability than the pristine Li4Ti5O12 in a voltage range of 0.1–2.5 V. However, ZrO2 coating with more than 5 ALD cycles could lead to degraded performance of Li4Ti5O12. Mechanism for the enhanced electrochemical performance of Li4Ti5O12 was explored by electrochemical impedance spectroscopy, and the reason was attributed to the suppressed formation of solid electrolyte interphase and the improved electron transport by ultrathin ZrO2 coating

  10. Plasmon Enhanced Electron and Atom Emission from a Spherical Sodium Cluster: Na91-

    International Nuclear Information System (INIS)

    The photoabsorption cross section of the negatively charged, spherical Na91- cluster shows a broad collective resonance at ℎω=2.65 eV, the decay of which can lead to two final channels: atom and electron emission. The branching ratio between the two channels was measured to increase linearly with photon energy over the unexpectedly broad energy range of 1.2 eV, which is attributed to the cluster close-quote s incipient valence band width. The femtosecond time scales of the processes involved are discussed. copyright 1996 The American Physical Society

  11. The calculation of photoionization angular distribution parameter β of atomic Na

    Institute of Scientific and Technical Information of China (English)

    刘锦超; 蒲丰年; 刘汉奎; 郭建军; 程延松; 杨向东

    1999-01-01

    The differential cross sections and angular distribution parameter of the photoionization processes 2p~63s→2p~53skl of atomic Na have been calculated by using many-body perturbation theory. In the calculation, the resonant structure of the excitation process 2s→3p has been included. The electron correlation interaction was analyzed by using the effective diagram method. The summation of specific classes of these diagrams is to an infinite order. The results of calculations are compared with experimental data, which are in good agreement with the experiment.

  12. Alkali-metal ion coordination in uranyl(VI) poly-peroxo complexes in solution, inorganic analogues to crown-ethers. Part 2. Complex formation in the tetramethyl ammonium-, Li(+)-, Na(+)- and K(+)-uranyl(VI)-peroxide-carbonate systems.

    Science.gov (United States)

    Zanonato, Pier Luigi; Szabó, Zoltán; Vallet, Valerie; Di Bernardo, Plinio; Grenthe, Ingmar

    2015-10-01

    The constitution and equilibrium constants of ternary uranyl(vi) peroxide carbonate complexes [(UO2)p(O2)q(CO3)r](2(p-q-r)) have been determined at 0 °C in 0.50 M MNO3, M = Li, K, and TMA (tetramethyl ammonium), ionic media using potentiometric and spectrophotometric data; (17)O NMR data were used to determine the number of complexes present. The formation of cyclic oligomers, "[(UO2)(O2)(CO3)]n", n = 4, 5, 6, with different stoichiometries depending on the ionic medium used, suggests that Li(+), Na(+), K(+) and TMA ions act as templates for the formation of uranyl peroxide rings where the uranyl-units are linked by μ-η(2)-η(2) bridged peroxide-ions. The templating effect is due to the coordination of the M(+)-ions to the uranyl oxygen atoms, where the coordination of Li(+) results in the formation of Li[(UO2)(O2)(CO3)]4(7-), Na(+) and K(+) in the formation of Na/K[(UO2)(O2)(CO3)]5(9-) complexes, while the large tetramethyl ammonium ion promotes the formation of two oligomers, TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-). The NMR spectra demonstrate that the coordination of Na(+) in the five- and six-membered oligomers is significantly stronger than that of TMA(+); these observations suggest that the templating effect is similar to the one observed in the synthesis of crown-ethers. The NMR experiments also demonstrate that the exchange between TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-) is slow on the (17)O chemical shift time-scale, while the exchange between TMA[(UO2)(O2)(CO3)]6(11-) and Na[(UO2)(O2)(CO3)]6(11-) is fast. There was no indication of the presence of large clusters of the type identified by Burns and Nyman (M. Nyman and P. C. Burns, Chem. Soc. Rev., 2012, 41, 7314-7367) and possible reasons for this and the implications for the synthesis of large clusters are briefly discussed. PMID:26331776

  13. Enhanced thermopower in an intergrowth cobalt oxide Li0.48Na0.35CoO2

    International Nuclear Information System (INIS)

    We report the measurements of thermopower, electrical resistivity and thermal conductivity in a complex cobalt oxide Li0.48Na0.35CoO2, whose crystal structure can be viewed as an intergrowth of the O3 phase of LixCoO2 and the P2 phase of NayCoO2 along the c-axis. The compound shows a large room-temperature thermopower of ∼180 μV K-1, which is substantially higher than those of LixCoO2 and NayCoO2. The figure of merit for the polycrystalline sample increases rapidly with increasing temperature, and achieves nearly 10-4 K-1 at 300 K, suggesting that the LixNayCoO2 system is a promising candidate for thermoelectric applications. (letter to the editor)

  14. Charge-exchange, ionization and excitation in low-energy Li$^{+}-$ Ar, K$^{+}-$ Ar, and Na$^{+}-$He collisions

    CERN Document Server

    Lomsadze, Ramaz A; Kezerashvili, RomanYa; Schulz, Michael

    2016-01-01

    Absolute cross sections are measured for charge-exchange, ionization, and excitation within the same experimental setup for the Li$^{+}-$Ar, K$^{+}-$ Ar, and Na$^{+}-$ He collisions in the ion energy range $0.5-10$ keV. Results of our measurements along with existing experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. The experimental results show that the charge-exchange processes are realized with high probabilities and electrons are predominately captured in ground states. The cross section ratio for charge exchange, ionization and excitation processes roughly attains the value $10:2:1$, respectively. The contributions of various partial inelastic channels to the total ionization cross sections are estimated and a primary mechanism for the process is defined. The energy-loss spectrum, in addition, is applied to estimate the relative contribution of different inelastic channels and to determine the mechanisms for the ionization and f...

  15. Electrochemical behaviours of lanthanide fluorides in the electrolysis system with LiF-NaF-Kf salt

    International Nuclear Information System (INIS)

    As a part of partitioning studies, the experiments of cyclic voltammetry and electrolytic reduction with the liquid bismuth cathode were conducted to investigate electrochemical behaviours of lanthanide elements in the electrorefining system employing LiF-NaF-KF eutectic salt as the electrolyte. The cyclic voltammograms for NdF3 and GdF3 were obtained at various potential scan rates, respectively. The cathodic and anodic peak currents of the elements increased in proportion to the square root of the potential scan rate. According to changes of the potential difference between the coupled cathodic and anodic peaks, reversibilities of the reduction-oxidation reactions in this system were evaluated. In addition, further behaviours of electrochemical reaction of the elements were examined through electrolytic tests of the system using liquid bismuth as the cathode at fixed current densities. (author)

  16. The solubility of lanthanum, samarium, and holmium oxides in eutectic melt LiF-NaF-KF

    International Nuclear Information System (INIS)

    With the method of isothermal saturation, the solubilities of La2O3, Sm2O3, and Ho2O3 in the eutectic melt LiF-NaF-KF are investigated. It is shown that the solubility of oxides of REE at the same temperature increases in the following sequence: Ho2O32O32O3. The temperature dependence in the temperature range 873-1073 K is satisfactorily approximated by the equation of line in coordinates: ln S - 1/T. Dissolution of the studied oxides obeys a mixed physical-chemical mechanism. The contribution of the chemical mechanism to the solubility increases in the sequence: Ho2O32O32O3.

  17. Subsolidus phase relations in the systems M2+-M2+O-V2O5 (M+-Li, Na, K, Rb, Cs; M2+-Mg, Ca)

    International Nuclear Information System (INIS)

    One studied phase composition of M2O(M2CO3)-MgO-V2O5 and M2O(M2CO3)-CaO-V2O5 systems, where M-Li, Na, K, Rb, Cs under the subsolidus temperatures. One synthesized 20 binary vanadates 5 ones of which (Rb2CaV2O7, Cs2CaV2O7, LiMg4(VO4)3, RbCaVO4 and CsCaVO4) were prepared for the first time. Paper presents summary table of structural characteristics of all binary vanadates. For 14 ones of them one presents structure and parameters of lattice (for 6 vanadates data were obtained for the first time). One shows formation of terminal solid solution based on calcium orthovanadate. One studied phase diagrams of 6 systems (M+-Li, Na, K, Rb, Cs; M2+-Mg, Ca)

  18. Synthesis and photoluminescence characterization of Ce3+ and Dy3+ activated ALa(WO4)2(A = Na and Li) novel phosphors

    Indian Academy of Sciences (India)

    Parag Nimishe; S J Dhoble

    2011-08-01

    In this paper, we report the synthesis of Ce3+ and Dy3+ activated alkali lanthanide tungstates, ALa(WO4)2(where A = Na and Li), prepared by solid state reaction method. The prepared phosphors were characterized by X-ray diffraction and photoluminescence techniques. The NaLa(WO4)2:Dy3+ and LiLa(WO4)2:Dy3+ phosphors show two emission peaks at around 574 and 486 nm (exc = 354 nm). NaLa(WO4)2:Ce3+ and LiLa(WO4)2:Ce3+ show two emission peaks at around 378 and 425 nm (exc = 350 nm). Excitation wavelengths of Ce3+ and Dy3+ activated alkali lanthanide tungstates are in near UV region i.e. Hg free excitation. These characterizations of phosphors are applicable for solid state lighting. Accordingly, Ce3+ and Dy3+ activated NaLa(WO4)2 and LiLa(WO4)2 may be the promising materials for solid state lighting applications.

  19. Phase Stability and Ionic Conductivity of NASICON-Like Phases in ScPO4-Na3PO4-Li3PO4 Ternary System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Phase formation in ternary system of complex Sc, Na and Li phosphates was studied at 950 ℃ and synthesis of new phases of definite composition was carried out. Obtained specimens were investigated with X-ray powder diffraction, infrared and impedance spectroscopy. Compositions of fields of homogeneity with NASICON-like structure were discovered. Temperature dependency of ionic conductivity was measured.

  20. Density functional theory study of Li, Na, and Mg intercalation and diffusion in MoS2 with controlled interlayer spacing

    Science.gov (United States)

    Shuai, Jing; Deog Yoo, Hyun; Liang, Yanliang; Li, Yifei; Yao, Yan; Grabow, Lars C.

    2016-06-01

    Layered materials, such as the transition metal dichalcogenide molybdenum disulfide (MoS2), are promising materials for ion storage in electrodes of rechargeable batteries. To extend the application range of these materials to ions beyond lithium-ions, we used van der Waals corrected density functional theory simulations to study the intercalation and diffusion of lithium (Li), sodium (Na), and magnesium (Mg) in the 2H structure of MoS2 as a function of interlayer spacing. All three species exhibit an optimal intercalation energy, which is reached at about 11% expansion for Li and Mg, and 23% expansion for Na. Similarly, the slow diffusion kinetics of large Na and divalent Mg-ions can be improved by layer expansion. When the interlayer spacing is increased by about 35% from its equilibrium value, the diffusion of Na and Mg-ions becomes more facile than the diffusion of small, monovalent Li-ions, with diffusion barriers similar to those of Li in graphene. Our results indicate that interlayer expansion is a promising technique to improve intercalation kinetics and thermodynamics for large and/or multivalent ions in MoS2, which can be a major limitation to battery performance. The rationalization of our results in terms of bonding geometries forms the basis of a battery electrode design framework with applications for a wide range of layered materials.

  1. Heat capacities and latent heats of LiNO/sub 3/, NaNO/sub 3/, and KNO/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Y.; Sakamoto, R.; Kamimoto, M.

    1988-11-01

    Enthalpies of fusion and transition together with heat capacities in both solid and liquid phases have been measured on LiNO/sub 3/, NaNO/sub 3/, and KNO/sub 3/, with a high accuracy by differential scanning calorimetry (DSC). Polynomial expressions of heat capacities are given.

  2. Electrochemical studies of the molten system K2NbF7-Na2O-Nb-(LiF-NaF-KF)(eut) at 700 degrees C

    DEFF Research Database (Denmark)

    Rosenkilde, C.; Vik, A.; Østvold, T.; Christensen, Erik; Bjerrum, Niels

    2000-01-01

    indications of the coexistence of the oxygen rich Nb(V)OF complexes and O-2(-) ions in FLINAK at n(O)(0)/n(Nb)(0) > 4 have been found. An equilibrium/sampling/analysis technique was also used to study this system without Nb metal added. The results mainly agree with the results of the voltammetric studies......Various voltammetric methods have been used to study FLINAK (LiF-NaF-KF eutectic melt 46.5-11.5-42 mol %) melts containing about 1 mol % niobium-fluoro and -oxofluoro complexes with Nh in oxidation states (V) and (IV) at 700 degrees C and varying amounts of Na2O in the range 0

  3. Electrochemical preparation of carbon films with a Mo2C interlayer in LiCl-NaCl-Na2CO3 melts

    International Nuclear Information System (INIS)

    Highlights: • The electrodeposition of carbon films with a Mo2C interlayer. • Carbon diffusion engenders the formation of Mo2C interlayer. • The Mo2C interlayer has a good adhesion. - Abstract: The electrodeposition of carbon films with a Mo2C interlayer was investigated in LiCl-NaCl-Na2CO3 melts at 900 °C. Cyclic voltammetry was applied to study the electrochemical reaction mechanism on Mo and Pt electrodes, indicating that, two reduction reactions including carbon deposition and carbon monoxide evolution, may take place on the two electrodes simultaneously during the cathodic sweep. Carbon films with a continuous Mo2C interlayer were prepared by constant voltage electrolysis, showing a good adhesion between Mo substrate and carbon films. The carbon films with a Mo2C interlayer were characterized using X-ray diffraction measurement, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The results reveal that carbon materials deposited on the electrodes are mainly composed of graphite and carbon diffusion in Mo (or Mo2C) leads to the formation and growth of Mo2C interlayer

  4. Electrochemical preparation of carbon films with a Mo{sub 2}C interlayer in LiCl-NaCl-Na{sub 2}CO{sub 3} melts

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jianbang; Wang, Shuai; Zhang, Feng; Zhang, Long; Jiao, Handong [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083 (China); Zhu, Hongmin [Department of Metallurgy, Materials Science, and Materials Processing, Tohoku University, Sendai 980-8579 (Japan); Jiao, Shuqiang, E-mail: sjiao@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing, 100083 (China)

    2015-08-30

    Highlights: • The electrodeposition of carbon films with a Mo{sub 2}C interlayer. • Carbon diffusion engenders the formation of Mo{sub 2}C interlayer. • The Mo{sub 2}C interlayer has a good adhesion. - Abstract: The electrodeposition of carbon films with a Mo{sub 2}C interlayer was investigated in LiCl-NaCl-Na{sub 2}CO{sub 3} melts at 900 °C. Cyclic voltammetry was applied to study the electrochemical reaction mechanism on Mo and Pt electrodes, indicating that, two reduction reactions including carbon deposition and carbon monoxide evolution, may take place on the two electrodes simultaneously during the cathodic sweep. Carbon films with a continuous Mo{sub 2}C interlayer were prepared by constant voltage electrolysis, showing a good adhesion between Mo substrate and carbon films. The carbon films with a Mo{sub 2}C interlayer were characterized using X-ray diffraction measurement, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The results reveal that carbon materials deposited on the electrodes are mainly composed of graphite and carbon diffusion in Mo (or Mo{sub 2}C) leads to the formation and growth of Mo{sub 2}C interlayer.

  5. Novel Rechargeable M3V2(PO4)3//Zinc (M = Li, Na) Hybrid Aqueous Batteries with Excellent Cycling Performance

    Science.gov (United States)

    Zhao, H. B.; Hu, C. J.; Cheng, H. W.; Fang, J. H.; Xie, Y. P.; Fang, W. Y.; Doan, T. N. L.; Hoang, T. K. A.; Xu, J. Q.; Chen, P.

    2016-05-01

    A rechargeable hybrid aqueous battery (ReHAB) containing NASICON-type M3V2(PO4)3 (M = Li, Na) as the cathodes and Zinc metal as the anode, working in Li2SO4-ZnSO4 aqueous electrolyte, has been studied. Both of Li3V2(PO4)3 and Na3V2(PO4)3 cathodes can be reversibly charge/discharge with the initial discharge capacity of 128 mAh g‑1 and 96 mAh g‑1 at 0.2C, respectively, with high up to 84% of capacity retention ratio after 200 cycles. The electrochemical assisted ex-XRD confirm that Li3V2(PO4)3 and Na3V2(PO4)3 are relative stable in aqueous electrolyte, and Na3V2(PO4)3 showed more complicated electrochemical mechanism due to the co-insertion of Li+ and Na+. The effect of pH of aqueous electrolyte and the dendrite of Zn on the cycling performance of as designed MVP/Zn ReHABs were investigated, and weak acidic aqueous electrolyte with pH around 4.0–4.5 was optimized. The float current test confirmed that the designed batteries are stable in aqueous electrolytes. The MVP//Zn ReHABs could be a potential candidate for future rechargeable aqueous battery due to their high safety, fast dynamic speed and adaptable electrochemical window. Moreover, this hybrid battery broadens the scope of battery material research from single-ion-involving to double-ions -involving rechargeable batteries.

  6. Semiclassical Calculation of Recurrence Spectra of Li Rydberg Atom in Crossed Electric and Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    WANG De-Hua; DING Shi-Liang

    2003-01-01

    Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the closed-orbit theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases; others persist till much higher f . As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.

  7. Semiclassical Calculation of Recurrence Spectra of Li Rydberg Atom in Crossed Electric and Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    WANGDe-Hua; DINGShi-Liang

    2003-01-01

    Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the dosed-orblt theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases, others persist till much higher f. As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.

  8. Crystallization behavior of (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses

    International Nuclear Information System (INIS)

    The crystallization behavior of the (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of β-spodumene. The isothermal crystallization kinetics of β-spodumene from the (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of β-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na2O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na2O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li2O.xNa2O.Al2O3.4SiO2 glasses.

  9. Electrochemical Behavior of Europium(III)-Europium(II) in LiF-NaF-KF Molten Salt

    International Nuclear Information System (INIS)

    The transformation of Eu(III) to Eu(II) was confirmed in a fluoride eutectic, LiF-NaF-KF (46.5-11.5-42.0 mol%, FLiNaK) molten salt during a treatment of high temperature as high as 1023 K. The coexistence of Eu(III)-Eu(II) was characterized by X-ray photoelectron spectroscopy (XPS) and voltammetry method, and their concentrations were measured. The electrochemical behavior of Eu(III) and Eu(II) in the fluoride salt was investigated. The mechanism of the electrode reaction was determined using cyclic voltammetry (CV) and square wave voltammetry (SWV). The results indicated a one-electron exchange process, corresponding to the reduction of Eu(III) to Eu(II) and the oxidation of Eu(II) to Eu(III). This process is reversible and diffusion-controlled. The diffusion coefficients (D) of Eu(III) and Eu(II) were determined using the conventional CV by changing the scanning rate and a modified method by changing the area of the working electrode successively. The values obtained by these two different methods were consistent. The temperature dependence of diffusion coefficient was investigated, and the activation energies of diffusion process were calculated to be 38.9 ± 4.6 kJ mol-1 for Eu(III) and 34.7 ± 1.6 kJ mol-1 for Eu(II), respectively

  10. Structure and properties of a rapidly solidified Al-Li-Mn-Zr alloy for high-temperature applications: Part II. spray atomization and deposition processing

    Science.gov (United States)

    Baram, Joseph

    1991-10-01

    A new Al-Li alloy containing 2.3 wt pct Li, 6.5 wt pct Mn, and 0.65 wt pet Zr for high-temperature applications has been processed by a rapid solidification (RS) technique (as compacts by spray atomization and deposition) and then thermomechanically treated by hot extrusion. As-received and thermomechanically treated deposits were characterized by X-ray diffraction and scanning electron microscopy (SEM). Phase analyses in the as-processed materials revealed the presence of two Mn phases (Al4Mn and Al6Mn), one Zr phase (Al3Zr), two Li phases (the stable AlLi and the metastable Al3Li), and the aAl solid solution with high excess in Mn solubility (up to close the nominal composition in the as-atomized powders). As-deposited and extruded pieces were given heating treatments at 430 °C and 530 °C. A two-step aging treatment was practiced, to check for the optimal (for tensile properties) aging procedure, which was found to be the following: solutioning at 430 °C for 1 hour and water quenching + a first-step aging at 120 °C for 12 hours + a second-step aging at 175 °C for 15 hours. The mechanical properties, at room and elevated temperatures, of the hot extruded deposits are compared, following the optimal solutioning and aging treatments. The room-temperature (RT) strength of the proposed alloy is distinctly better for the as-deposited specimens (highest yield strength, 320 MPa) than for the as-atomized (highest yield strength, 215 MPa), though less than 65 pct of the RT strength is conserved at 250 °C. Ultimate strengths are quite comparable (in the 420 to 470 MPa range). Ductilities at RTs are in the low 1.5 to 2.5 pct range and show no improvement over other Al-Li alloys.

  11. Atom Diffraction Reveals the Impact of Atomic Core Electrons on Atom-Surface Potentials

    International Nuclear Information System (INIS)

    We measured ratios of van der Waals potential coefficients (C3) for different atoms (Li, Na, K, and Rb) interacting with the same surface by studying atom diffraction from a nanograting. These measurements are a sensitive test of atomic structure calculations because C3 ratios are strongly influenced by core electrons and only weakly influenced by the permittivity and geometry of the surface. Our measurement uncertainty of 2% in the ratio C3K/C3Na is close to the uncertainty of the best theoretical predictions, and some of these predictions are inconsistent with our measurement.

  12. Structures of Li-Doped Alkali Clusters are Dictated by AO-Hybridization

    CERN Document Server

    Alexandrova, Anastassia N

    2012-01-01

    Hybridization of atomic orbitals is a widely appreciated phenomenon whose impact on the structure and properties of, for example, organic molecules is well-established. Here, we demonstrate that hybridization also dramatically impacts the shapes of small alkali metal clusters. The seemingly similar and valence-iso-electronic LiNa4- and LiK4- clusters adopt very different global minimum structures: LiNa4- is a planar C2v (1A1) species distorted from the perfect pentagon due to the pseudo Jahn-Teller effect, and LiK4- is a planar square D4h (1A1g) species with Li being in the centre. This effect is rooted in the different degrees of the 2s-2p hybridization in Li in response to binding to Na versus K. Li inside the Na cluster exhibits a strong 2s-2p mixing, to achieve stronger covalent bonding. In contrast, Li inside of the K cluster does not show any hybridization, and the LiK4- cluster is reminiscent of an ionic salt. These differences are tied to the relative electronegativities of Li, Na, and K, and overlap ...

  13. Experimental study of phase equilibria in the (AgNO3 + LiNO3 + NaNO3) ternary system

    International Nuclear Information System (INIS)

    Highlights: • Alkali nitrates are potential materials for the storage of thermal energy. • Phase diagrams of alkali nitrate systems are essential for a better use. • We are interested in the phase diagram of the (Ag, Li, Na)NO3 system. • A new set of thermodynamic parameters of ternary liquid was obtained. -- Abstract: Seven sections, in the ternary phase diagram (AgNO3 + LiNO3 + NaNO3) were studied at atmospheric pressure by means of differential thermal analysis (DTA) and differential scanning calorimetry (DSC): X(AgNO3) = 0.1 and 0.8, X(AgNO3)/X(LiNO3) = 3/2 and 2/3, X(LiNO3) = 0.2, and X(NaNO3) = 0.258 and 0.3. The results exhibit two invariant reactions: a eutectoïd at T = 380 K and a eutectic at T = 440 K

  14. Corrosion behaviour of Ti3SiC2 with LiF-NaF-KF molten salt

    International Nuclear Information System (INIS)

    Background: Recently, the molten salt reactor (MSR), a generation IV fission reactor candidate, has drawn much attention because of its intrinsic safety. However, the harsh service environment of the MSR, especially the corrosion environment, raises many challenges in terms of applying structural materials, such as intergranular cracking and embrittlement. MAX phases materials are promising structural materials that can be used in MSRs. However, the corrosion behaviour of these materials in molten LiF-NaF-KF (FLiNaK) is yet to be evaluated. Purpose: The present work is a preliminary investigation of the corrosion behaviour of MAX phase materials in molten fluoride salts and aims to understand the corrosion mechanism of MAX phases to enable their application in next generation MSR. Methods: We choose two common MAX phases: Ti3SiC2 and Ti3AlC2 as experiment subject. The corrosion tests were performed at 850℃ for 144 h in airtight graphite crucibles under an argon cover gas. Results and Conclusion: The corrosion of these two MAX phases in molten FLiNaK salt mainly showed as the corrosion of element A and then left us mostly cubic TiCx. The difference was that Ti3AlC2 lost Al entirely, however, the loss of Si in Ti3SiC2 occurred only 150 μm depth below the surface. The weight loss data showed that Ti3SiC2 had a much better corrosion resistance than Ti3AlC2. (authors)

  15. Effects of laser energy and wavelength on the analysis of LiFePO4 using laser assisted atom probe tomography

    International Nuclear Information System (INIS)

    The effects of laser wavelength (355 nm and 532 nm) and laser pulse energy on the quantitative analysis of LiFePO4 by atom probe tomography are considered. A systematic investigation of ultraviolet (UV, 355 nm) and green (532 nm) laser assisted field evaporation has revealed distinctly different behaviors. With the use of a UV laser, the major issue was identified as the preferential loss of oxygen (up to 10 at%) while other elements (Li, Fe and P) were observed to be close to nominal ratios. Lowering the laser energy per pulse to 1 pJ/pulse from 50 pJ/pulse increased the observed oxygen concentration to nearer its correct stoichiometry, which was also well correlated with systematically higher concentrations of 16O2+ ions. Green laser assisted field evaporation led to the selective loss of Li (∼33% deficiency) and a relatively minor O deficiency. The loss of Li is likely a result of selective dc evaporation of Li between or after laser pulses. Comparison of the UV and green laser data suggests that the green wavelength energy was absorbed less efficiently than the UV wavelength because of differences in absorption at 355 and 532 nm for LiFePO4. Plotting of multihit events on Saxey plots also revealed a strong neutral O2 loss from molecular dissociation, but quantification of this loss was insufficient to account for the observed oxygen deficiency. - Highlights: • Laser wavelength and pulse energy affect accuracy of APT analysis of LiFePO4. • Oxygen deficiency observed for UV laser; stronger at higher laser energies. • Selective loss of Li with green laser due to dc evaporation. • Saxey plots reveal prevalent formation of O2 neutrals. • Quantification of molecular dissociations cannot account for O deficiency

  16. Effects of laser energy and wavelength on the analysis of LiFePO{sub 4} using laser assisted atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Santhanagopalan, Dhamodaran [Department of NanoEngineering, University of California San Diego, CA 92093 (United States); Schreiber, Daniel K. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Perea, Daniel E. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Martens, Richard L. [Central Analytical Facility, University of Alabama, Tuscaloosa, AL 35487 (United States); Janssen, Yuri [Department of Chemistry, Stony Brook University, Stony Brook, NY 11790-3400 (United States); Khalifah, Peter [Department of Chemistry, Stony Brook University, Stony Brook, NY 11790-3400 (United States); Department of Chemistry, Brookhaven National Laboratory, Upton, NY 11793-5000 (United States); Meng, Ying Shirley, E-mail: shirleymeng@ucsd.edu [Department of NanoEngineering, University of California San Diego, CA 92093 (United States)

    2015-01-15

    The effects of laser wavelength (355 nm and 532 nm) and laser pulse energy on the quantitative analysis of LiFePO{sub 4} by atom probe tomography are considered. A systematic investigation of ultraviolet (UV, 355 nm) and green (532 nm) laser assisted field evaporation has revealed distinctly different behaviors. With the use of a UV laser, the major issue was identified as the preferential loss of oxygen (up to 10 at%) while other elements (Li, Fe and P) were observed to be close to nominal ratios. Lowering the laser energy per pulse to 1 pJ/pulse from 50 pJ/pulse increased the observed oxygen concentration to nearer its correct stoichiometry, which was also well correlated with systematically higher concentrations of {sup 16}O{sub 2}{sup +} ions. Green laser assisted field evaporation led to the selective loss of Li (∼33% deficiency) and a relatively minor O deficiency. The loss of Li is likely a result of selective dc evaporation of Li between or after laser pulses. Comparison of the UV and green laser data suggests that the green wavelength energy was absorbed less efficiently than the UV wavelength because of differences in absorption at 355 and 532 nm for LiFePO{sub 4}. Plotting of multihit events on Saxey plots also revealed a strong neutral O{sub 2} loss from molecular dissociation, but quantification of this loss was insufficient to account for the observed oxygen deficiency. - Highlights: • Laser wavelength and pulse energy affect accuracy of APT analysis of LiFePO{sub 4}. • Oxygen deficiency observed for UV laser; stronger at higher laser energies. • Selective loss of Li with green laser due to dc evaporation. • Saxey plots reveal prevalent formation of O{sub 2} neutrals. • Quantification of molecular dissociations cannot account for O deficiency.

  17. Je li Austro – Ugarska bila osuđena na propast?

    OpenAIRE

    Suppan, Arnold

    2015-01-01

    Autor analizira društvene i političke prilike u Habsburškoj Monarhij i te međunarodne odnose u drugoj polovici 19. i na početku 19. st. Donosi podatke o slijedu zbivanja koja su dovela do odluke o pokretanju rata Monarhije protiv Srbije 1914. i time izbijanja Prvog svjetskog rata te o razvoju prilika na ratištima, u društvenim i političkim odnosima u zemlji i svijetu koji su 1918. god. doveli do raspada Habsburške Monarhije.

  18. Conditioning of Waste LiCl Salt from Pyrochemical Process Using Zeolite A

    International Nuclear Information System (INIS)

    The electrolytic (LiCl-Li2O) reduction process (Advanced spent fuel Conditioning Process; ACP) and the electrorefining process, which are being developed by the Korea Atomic Energy Research Institute (KAERI), are to generate two types of molten salt wastes such as a LiCl salt and a LiCl-KCl eutectic salt, respectively. These waste salts must meet certain criteria for a disposal. A conditioning process composed of an immobilization and then a thermal treatment, for LiCl salt waste from the ACP has been developed using zeolite A. The immobilization of molten LiCl salt waste was conducted in a blender by mixing it with zeolite A at 923 K, producing a salt-loaded zeolite (SLZ). During the immobilization, the zeolite A was transformed to zeolite Li-A [Li2Al2Si2O80], with some minor phases such as a Li-type sodalite [Li8Cl2-Sod; Li8(AlSiO4)6Cl2] and Nepheline for some zeolite-rich condition. In order to obtain a final ceramic waste form with Na-type sodalite [Na8Cl2-Sod; Na8(AlSiO4)6Cl2], the very highly leach-resistant crystal phase, the SLZ with r (=LiCl/zeolite) < 0.3 should be treated in a high temperature furnace above 1173 K, which was independent from an addition of glass frit during a mixing. (authors)

  19. On the molybdenum tellurates of Li+, Na+, Rb+, Cs+ and NH4+

    International Nuclear Information System (INIS)

    The heteropoly compounds often crystallize with a high water content and are thus capable of forming hydrogen bridges. These hydrogen bridges have until now attracted undeservedly little attention in the literature. This is all the more surprising considering the already mentioned fact that some polywolframates have remarkable physiological properties (antifumoural or antiviral effects), as do molybdates and vanadates. The hydrogen bridge bonds undoubtedly play a capital role in the interactions with the biologic substrate. The aim of the study was the preparation, chemical and spectroscopic characterisation (in particular IR and 125Te-NMR spectroscopy) and X-ray structural analysis of molybdenum tellurates. Further the proton acceptor behaviour of the ANDERSON-EVANS anion was examined. The oxygen atoms surrounding the Mo-atoms and the Te atom are uni-, bi- or trivalent. This raises the question whether the different covalences influence the hydrogen bridge bonding behaviour of the ANDERSON-EVANS anion ([TeMo6O24]6-). (orig./BBR)

  20. Thermal analysis and phase diagrams of the LiF BiF{sub 3} e NaF BiF{sub 3} systems; Analise termica e diagramas de fase dos sistemas LiF-BiF{sub 3} e NaF-BiF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Gerson Hiroshi de Godoy

    2013-07-01

    Investigations of the binary systems LiF-BiF{sub 3} and NaF-BiF{sub 3} were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF{sub 3}) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF{sub 3} to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF{sub 3} were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF{sub 4}, decomposes into LiF and a liquid phase. The NaF-BiF{sub 3} system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF{sub 3}) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF{sub 4} was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF{sub 4}, NaBiF{sub 4} and a solid solution of NaF and BiF{sub 3} called {sup I.} The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

  1. Multi-reference Hartree-Fock configuration interaction calculations of LiH and Be using a new double-zeta atomic base.

    Science.gov (United States)

    de Cerqueira Sobrinho, Antonio Moreira; de Andrade, Micael Dias; Nascimento, Marco Antônio Chaer; Malbouisson, Luiz Augusto Carvalho

    2014-08-01

    In this work, we propose new double-zeta atomic bases for the Li and Be atoms. These were obtained by applying the Hartree-Fock-Gauss generalized simulated annealing (GSA) method-a modified form of the GSA algorithm. The new bases were generated through optimization of the atomic electronic energy functional with regards to the linear combination of atomic orbitals-molecular orbital (LCAO-MO) coefficients, and exponent and contraction coefficients of the primitive Gaussian functions, simultaneously. These new bases were tested by performing calculations of the ground state energy of the Be atom, and the ground state energy and permanent electrical dipole moment of the LiH molecule, using the multi-reference Hartree-Fock (HF) configuration interaction method-a multi-reference method based on multiple HF solutions. In addition, multi-reference HF configuration interaction calculations were performed for the Be atom using the standard double-zeta, triple-zeta and polarized double-zeta bases. With the new double-zeta bases and with reduced multi-reference HF bases, it was possible to obtain lower energies than those obtained with the full configuration interaction calculations using the standard double-zeta bases and dipole moment values in close agreement with experimental values. PMID:25102937

  2. Application of potential harmonic expansion method to BEC: Thermodynamic properties of trapped 23Na atoms

    Indian Academy of Sciences (India)

    Anasuya Kundu; Barnali Chakrabarti; Tapan Kumar Das

    2005-07-01

    We adopt the potential harmonics expansion method for an ab initio solution of the many-body system in a Bose condensate containing interacting bosons. Unlike commonly adopted mean-field theories, our method is capable of handling two-body correlation properly. We disregard three- and higher-body correlations. This simplification is ideally suited to dilute Bose Einstein condensates, whose number density is required to be so small that the interparticle separation is much larger than the range of two-body interaction to avoid three- and higher-body collisions, leading to the formation of molecules and consequent instability of the condensate. In our method we can incorporate realistic finite range interactions. We calculate energies of low-lying states of a condensate containing 23Na atoms and some thermodynamical properties of the condensate.

  3. Cluster self-organization of intermetallic systems: Quasi-spherical nanocluster precursors with internal Friauf polyhedra (A-172) and icosahedra (B-137) in the Li19Na8Ba15 (hP842) crystal structure

    International Nuclear Information System (INIS)

    A combinatorial and topological analysis of Li19Na8Ba15 (hP842, a = 20 A, c = 93 A, V = 33552 A3, P3-bar) has been performed using computer methods (the TOPOS program package). Two types of crystal-forming quasi-spherical nanoclusters about 20 A in diameter with internal Friauf polyhedra (A-172) and icosahedra (B-137) have been established by the complete decomposition of the 3D factor graph of the structure into cluster substructures. Each type of nanoclusters forms close-packed 2D layers 36, which alternate along the c axis. The B-137 and A-172 nanoclusters are composed of three layers and have shell compositions (1 + 12 + 32 + 92) and (1 + 16 + 59 + 103) with local symmetries 3 and 3-bar, respectively; they were revealed for the first time in crystal structures as cluster precursors. The icosahedral B-137 nanocluster contains a 104-atom quasicrystal approximant (Samson cluster).

  4. Core-shell Si@TiO2 nanosphere anode by atomic layer deposition for Li-ion batteries

    Science.gov (United States)

    Bai, Ying; Yan, Dong; Yu, Caiyan; Cao, Lina; Wang, Chunlei; Zhang, Jinshui; Zhu, Huiyuan; Hu, Yong-Sheng; Dai, Sheng; Lu, Junling; Zhang, Weifeng

    2016-03-01

    Silicon (Si) has been regarded as next-generation anode for high-energy lithium-ion batteries (LIBs) due to its high Li storage capacity (4200 mA h g-1). However, the mechanical degradation and resultant capacity fade critically hinder its practical application. In this regard, we demonstrate that nanocoating of Si spheres with a 3 nm titanium dioxide (TiO2) layer via atomic layer deposition (ALD) can utmostly balance the high conductivity and the good structural stability to improve the cycling stability of Si core material. The resultant sample, Si@TiO2-3 nm core-shell nanospheres, exhibits the best electrochemical performance of all with a highest initial Coulombic efficiency and specific charge capacity retention after 50 cycles at 0.1C (82.39% and 1580.3 mA h g-1). In addition to making full advantage of the ALD technique, we believe that our strategy and comprehension in coating the electrode and the active material could provide a useful pathway towards enhancing Si anode material itself and community of LIBs.

  5. Liquidus temperatures of Na3AlF6-AlF3-CaF2-KF-LiF-Al2O3 melts

    OpenAIRE

    Peng J.P.; Di Y.Z.; Wang Y.W.; Bai Y.B.; Feng N.X.

    2014-01-01

    Temperatures for the primary crystallization of Na3AlF6-AlF3-CaF2-KF-LiF-Al2O3 system adopted in aluminum electrolysis process were determined by thermal analysis. An empirical equation was derived to describe the liquidus temperatures for the primary crystallization of this multicomponent electrolyte system: t/℃=1011 + 0.7w(AlF3) - 0.232w(AlF3)2 - 7.65w(Al2O3) + 0.523w(Al2O3)2 - 8.96w(LiF) + 0.043w(LiF)2 - 3.32w(KF) - 0.12w(KF)2 - 3.28w(CaF2) +0.037w(CaF2)2 + 0.09...

  6. Hyperfine splitting and isotope shift of 22Na, 23Na by high resolution laser spectroscopy at the atomic D2-line

    International Nuclear Information System (INIS)

    The hyperfine structure of D2 optical line in 22Na and 23Na has been investigated using high resolution laser spectroscopy of a well-collimated atomic beam. The hyperfine splitting constants A and B for the excited 3p2P3/2 level for both investigated sodium isotopes have been obtained. They are as follows: A(22)=7.31(4) MHz, B(22)=4.71(28) MHz, A(23)=18.572(24) MHz, B(23)=2.723(55) MHz. With these data, using the high precision MCHFF calculations for the electric field gradient at the nucleus, the electric quadrupole moment of 22Na has been deduced: Qs(22)=+0.185(11) b. The sign of Qs(22), determined for the first time, indicates a prolate nuclear deformation. Precise value of the isotope shift 22,23Na in D2-line has also been obtained

  7. Electronic properties and structural phase transition in A4 [M4O4] (A=Li, Na, K and Rb; M=Ag and Cu): A first principles study

    Science.gov (United States)

    Umamaheswari, R.; Yogeswari, M.; Kalpana, G.

    2013-02-01

    Self-consistent scalar relativistic band structure calculations for AMO (A=Li, Na, K and Rb; M=Ag and Cu) compounds have been performed using the tight-binding linear muffin-tin orbital (TB-LMTO) method within the local density approximation (LDA). At ambient conditions, these compounds are found to crystallize in tetragonal KAgO-type structure with two different space group I-4m2 and I4/mmm. Nowadays, hypothetical structures are being considered to look for new functional materials. AMO compounds have stoichiometry similar to eight-electron half-Heusler materials of type I-I-VI which crystallizes in cubic (C1b) MgAgAs-type structure with space group F-43m. For all these compounds, by interchanging the positions of atoms in the hypothetical cubic structure, three phases (α, β and γ) are formed. The energy-volume relation for these compounds in tetragonal KAgO-type structure and cubic α, β and γ phases of related structure have been obtained. Under ambient conditions these compounds are more stable in tetragonal KAgO-type (I4/mmm) structure. The total energies calculated within the atomic sphere approximation (ASA) were used to determine the ground state properties such as equilibrium lattice parameters, c/a ratio, bulk modulus, cohesive energy and are compared with the available experimental results. The results of the electronic band structure calculations at ambient condition show that LiCuO and NaMO are indirect band gap semiconductors whereas KMO and RbMO are direct band gap semiconductors. At high pressure the band gap decreases and the phenomenon of band overlap metallization occur. Also these compounds undergo structural phase transition from tetragonal I-4m2 phase to cubic α-phase and transition pressures were calculated.

  8. Partial exchange of the Li+, Na+ and K+ alkaline cations in the HNi(PO4).H2O layered compound

    International Nuclear Information System (INIS)

    The exchange of the Li+(1), Na+(2) and K+(3) alkaline cations in the layered HNi(PO4).H2O was carried out starting from a methanolic solution containing the Li(OH).H2O hydroxide for (1) and the M(OH) (M=Na and K) hydroxides together with the (C6H13NH2)0.75HNiPO4.H2O phases for (2) and (3). The compounds are stable until, approximately, 280oC for (1) and 400 deg. C for phases (2) and (3), respectively. The IR spectra show the bands belonging to the water molecule and the (PO4)3- oxoanion. The diffuse reflectance spectra indicate the existence of Ni(II), d8, cations in slightly distorted octahedral geometry. The calculated Dq and Racah (B and C) parameters have a mean value of Dq=765, B=905 and C=3895cm-1, respectively, in accordance with the values obtained habitually for this octahedral Ni(II) cation. The study of the exchange process performed by X-ray powder diffraction indicates that the exchange of the Li+ cation in the lamellar HNi(PO4).H2O phase is the minor rapid reaction, whereas the exchange of the Na+ and K+ cations needs the presence of the intermediate (C6H13NH2)0.75HNiPO4.H2O intercalate in order to obtain the required product with the sodium and potassium ions. The Scanning electronic microscopy (SEM) images show a mean size of particle of 5μm. The Li+ exchanged compound exhibits small ionic conductivity (Ωcm-1 is in the 10-8-10-9 range) probably restrained by the methanol solvent. Magnetic measurements carried out from 5K to room temperature indicate antiferromagnetic coupling as the major interaction in the three phases. Notwithstanding the Li and K phases show a weak ferromagnetism at low temperatures

  9. Band gap modification and ferroelectric properties of Bi0.5(Na,K0.5TiO3-based by Li substitution

    Directory of Open Access Journals (Sweden)

    Ngo Duc Quan

    2014-01-01

    Full Text Available We report on the reduction of band gap in Bi0.5(Na0.82-xLixK0.180.5(Ti0.95Sn0.05O3 from 2.99 eV to 2.84 eV due to the substitutions of Li+ ions to Na+ sites. In addition, the lithium substitution samples exhibit an increasing of the maximal polarizations from 21.8 to 25.7 μC/cm2. The polarization enhancement of ferroelectric and reduction of the band gaps are strongly related to the Li substitution concentration as evaluated via the electronegative between A-site and oxygen and tolerance factor. The results are promising for photovoltaic and photocatalytic applications.

  10. Characterization of Anthraquinone-DerivedRedox Switchable Ionophores and Their Complexes with Li+, Na+, K+, Ca+, and Mg+ Metal Ions

    Directory of Open Access Journals (Sweden)

    Vaishali Vyas

    2011-01-01

    Full Text Available Anthraquinone derived redox switchable ionophores 1,5 bis (2-(2-(2-ethoxy ethoxy ethoxyanthracene-9,10-dione (V1 and 1,8-bis(2-(2-(2-ethoxyethoxyethoxy anthracene—9,10-dione (V2 have been used for isolation, extraction and liquid membrane transport studies of Li+, Na+, K+, Ca2+ and Mg2+ metal ions. These isolated complexes were characterized by melting point determination, CV and IR, 1H NMR spectral analysis. Ionophore V2 shows maximum shift in reduction potential (ΔE with Ca(Pic2. The observed sequence for the shifting in reduction potential (ΔE between V2 and their complexes is V2 calcium picrate (42 mV > V2 potassium picrate (33 mV > V2 lithium picrate (25 mV > V2 sodium picrate (18 mV > V2 magnesium picrate (15 mV. These findings are also supported by results of extraction, back extraction and transport studies. Ionophore V2 complexed with KPic and showed much higher extractability and selectivity towards K+ than V1. These synthetic ionophores show positive and negative cooperativity towards alkali and alkaline earth metal ions in reduced and oxidized state. Hence, this property can be used in selective separation and enrichment of metal ions using electrochemically driven ion transport.

  11. Vibrational investigation and phase transitions in the KMnF3 doped perovskite crystals (Li'+, Na+, Rb+ and Cs+)

    International Nuclear Information System (INIS)

    The influence of substitution of Li+, Na+, Rb+ and Cs+ ions in the archetype KMnF3 perovskite crystal was studied by the Raman method. The Raman spectra of (K1-xAx)MnF3 mixed crystals (x≤0.15) were recorded in the range between 30 and 300 K and interpreted in terms of a 'one-mode' behaviour. Attention was paid to evidence of the static and dynamical disorder. From this point of view the behaviour of hard Raman modes versus temperature has been studied together with two unexpected broad Raman bands in the normally inactive ideal cubic phase. The existence of these two broad peaks in the theoretically inactive cubic phase and also the persistence of the hard Raman modes of the tetragonal phase in cubic symmetry suggest the existence of a large structural disorder far above the cubic-to-tetragonal phase transition. The results of Raman investigations are discussed in the more general framework of structural disorder in perovskite systems. (author)

  12. Compatibility of ZrN and HfN with molten LiCl-KCl-NaCl-UCl3

    International Nuclear Information System (INIS)

    The reaction kinetics of ZrN and HfN immersed in a quaternary salt of composition of 28.5% LiCl-36.3% KCl-29.4% NaCl-5.8% UCl3 (in weight percent) were assessed. Coupons of ZrN and HfN were exposed to the quaternary salt at 525-900 oC for 4-485 h. The reaction kinetics of the salt-refractory interactions were assessed through physical and microstructural characterization including scanning electron microscopy, X-ray diffraction and mass spectrometry. The results indicated that ZrN and HfN lose weight under all conditions investigated. While multiple mechanisms were evident, it is proposed that dissolution and oxidation were the dominant reactions that influence the weight loss. For the overall reaction, negative apparent activation energy values of -46 and -28 kJ/mol were observed in ZrN and HfN, respectively. These seemingly anomalous activation energies were associated with the simultaneous occurrence of electrochemical dissolution and surface oxide formation.

  13. Statistics of electron and exciton production for grazing impact of keV hydrogen atoms on a LiF(001) surface

    Science.gov (United States)

    Winter, H.; Lederer, S.; Maass, K.; Mertens, A.; Aumayr, F.; Winter, HP

    2002-08-01

    The energy loss of kilo-electronvolt hydrogen atoms for scattering from a LiF(001) surface under a grazing angle of incidence is measured in coincidence with the number of emitted electrons. The combined time-of-flight and electron number distributions show discrete features which are attributed to specific numbers for emitted electrons and production of surface excitons. The distributions are fairly well reproduced in terms of binomial distributions. The corresponding probabilities for electron and exciton production can consistently be related to a model where the formation of negative hydrogen atoms via local electron capture from halogen lattice sites is considered as a precursor for both processes.

  14. Performance testing of personnel extremity dosimeters by Korean LiF: Mg, Cu, Na, Si TLD(KLT-300)

    International Nuclear Information System (INIS)

    Full text: As the needs and opportunities for utilization of atomic energy and radiation are increasing, the related industries, medicines, environments are developing and the relevant organizations and companies are also becoming diverse. In result, the types and kinds of the radiation related to occupational environments are becoming diversified. For the whole body dosimeters, the methodology and criteria for the performance evaluation and safety regulations and laws have been prepared in some detail, but for the extremity dosimeters, those are not prepared yet in Korea. The extremity dosimeters are required when the extremity part of our body, such as hand, elbow, and arm below the elbow, the foot, knee, and leg below the knee are exposed to the radiation in specific work environments. The dosimeter irradiation conditions are clearly discriminated between the whole body exposure condition and the extremity exposure condition. By the investigation and analysis of the management status and dose evaluation methods of the extremity dosimeters for the local absorbed dose, the personnel monitoring system of the extremity dosimeter services in Korea can be diagnosed, and the performance testing criteria and procedures can be established. Therefore, this study presents the performance testing results of extremity dosimeters on the finger and arm/leg phantoms by the procedures recommended in the ANSI (American National Standard) N13.32 using KLT-300 TL materials (LiF:Mg,Cu,Nas,Si) which were developed in Korea Atomic Energy Research Institute (KAERI). The results show that the performance index for the two types of phantoms are sufficiently satisfied with the prescribed tolerance level in the all of the test categories listed in the ANSI N13.32. These results and procedures used in this study can be applicable for regulatory body to establish the standard criteria for acceptable performance and testing conditions for personnel extremity dosimeters services in the

  15. Crystal growth of Na co-doped Ce:LiCaAlF single crystals and their optical, scintillation and physical properties

    Czech Academy of Sciences Publication Activity Database

    Yokota, Y.; Fujimoto, Y.; Yanagida, T.; Takahashi, H.; Yonetani, M.; Hayashi, K.; Park, I.; Kawaguchi, N.; Fukuda, K.; Yamaji, A.; Fukazawa, Y.; Nikl, Martin; Yoshikawa, A.

    2011-01-01

    Roč. 11, č. 11 (2011), 4775–4779. ISSN 1528-7483 Grant ostatní: AVČR(CZ) M100100910 Institutional research plan: CEZ:AV0Z10100521 Keywords : LiCaAlF 6 * Ce- doped * Na-codoped * fluoride * neutron scintillator * micro-pulling down method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.720, year: 2011

  16. THE EFFECT OF HYDROGEN DURING STRESS CORROSION CRACKING AND CORROSION FATIGUE OF Al-Li-Cu ALLOYS IN 3.5 % NaCl SOLUTIONS

    OpenAIRE

    Magnin, T; RebiÈre, M.

    1987-01-01

    Stress corrosion cracking and corrosion fatigue tests at imposed strain rate are conducted on an industrial Al-Li-Cu alloy in a 3.5 % NaCl solution at imposed potential. In the condition of the tests and for short fatigue lifetimes, the anodic dissolution is shown to play the predominant role during corrosion-fatigue at free corrosion potential. Nevertheless a marked hydrogen embrittlement is observed at cathodic potentials during corrosion fatigue of specimens containing superficial microcra...

  17. Huntington hastalığına bağlı psikotik bozukluk ve tedaviye dirençli obsesif kompulsif bozukluk

    OpenAIRE

    Nurhan FISTIKCI; SAATCİOĞLU, Ömer; ERTEN, Evrim; YILMAZ, Görkem; ÇALCI, Çağrı; Keyvan, Ali

    2015-01-01

    Huntington hastalığına bağlı gelişen psikiyatrik sorunların başında psikotik belirtiler, homisid ve özkıyım gelmektedir. Bu olguda, Huntington hastalığına bağlı psikotik bozukluk ve eşlik eden tedaviye dirençli obsesif kompulsif bozukluk tanısı olan bir hasta sunulmuştur.Anahtar kelimeler: Huntington hastalığı, Obsesif kompulsif bozukluk, Psikoz

  18. Effects of Er{sup 3+} and Yb{sup 3+} doping on structural and non-linear optical properties of LiNaSO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Palmero, I.C. [Departamento de Fisica Basica, Electronica y Sistemas, Universidad de La Laguna, E-38200, San Cristobal de la Laguna, Santa Cruz de Tenerife (Spain); Gonzalez-Silgo, C. [Departamento de Fisica Fundamental II, Electronica y Sistemas, Universidad de La Laguna, E-38200, San Cristobal de la Laguna, Santa Cruz de Tenerife (Spain); Torres, M.E. [Departamento de Fisica Basica, Electronica y Sistemas, Universidad de La Laguna, E-38200, San Cristobal de la Laguna, Santa Cruz de Tenerife (Spain); Marrero-Lopez, D. [Departamento de Quimica Inorganica, Electronica y Sistemas, Universidad de La Laguna, E-38200, San Cristobal de la Laguna, Santa Cruz de Tenerife (Spain); Rivera-Lopez, Fernando [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, E-38200, San Cristobal de la Laguna, Santa Cruz de Tenerife (Spain)], E-mail: frivera@ull.es; Haro-Gonzalez, P. [Departamento de Fisica Fundamental y Experimental, Electronica y Sistemas, Universidad de La Laguna, E-38200, San Cristobal de la Laguna, Santa Cruz de Tenerife (Spain); Solans, X. [Departament de Cristallografia, Universitat de Barcelona, E-08028, Barcelona (Spain)

    2008-05-15

    We have characterized LiNaSO{sub 4} crystals doped with rare earth (RE) (Er{sup 3+} and Yb{sup 3+}) to give new insights about their structural properties relations. The samples were analyzed by X-ray single crystal diffraction and differential thermal analysis. The non-centrosymmetry was confirmed second-harmonic generation. Inductively coupled plasma (ICP) and emission experiments confirmed the nominal concentrations of the REs. Crystallographic data and two empirical models were employed to understand the structural modifications by substitution of the Na site which reduces, monotonically, the non-linear optical coefficients and the temperature of the phase transition in these crystals.

  19. Dielectric and electromechanical properties of LiNbO3-modified (BiNa)TiO3-(BaCa)TiO3 lead-free piezoceramics

    Science.gov (United States)

    Zaman, Arif; Hussain, Ali; Malik, Rizwan Ahmed; Maqbool, Adnan; Nahm, Sahn; Kim, Myong-Ho

    2016-05-01

    The dielectric and electromechanical properties of LiNbO3-modified (1-x) [0.91Na0.5Bi0.5TiO3-0.09Ba0.70Ca0.30TiO3]-xLiNbO3 (abbreviated as (BiNa)TiO3-(BaCa)TiO3-LN) lead-free piezoceramics were investigated. The electrical properties revealed that the addition of LiNbO3 (LN) induces a phase transition from a non-ergodic relaxor to an ergodic relaxor in the (BiNa)TiO3-(BaCa)TiO3-LN system. A large electrostrain of ~0.418% with a normalized strain of ~690 pm V-1 at 6 kV mm-1 was observed at the coexistence of the non-ergodic relaxor and ergodic relaxor phases for LN 0.020, where a field-assisted reversible phase transition between metastable ferroelectric and stable ergodic relaxor phases occurs. Subsequently, a gradual enhancement in the temperature stability of the dielectric constant was observed. At 3 mol.% LN, a nearly constant temperature and a frequency-invariant permittivity of ɛ r ~ 3300 over a broad temperature range of 147 °C-306 °C was observed along with small losses from room temperature up to 400 °C.

  20. Enhancement of green emission by the codoping A+ (A = Li, Na, K) in Ca2BO3Cl:Tb3+ phosphor

    International Nuclear Information System (INIS)

    Tb3+-doped Ca2BO3Cl compounds with different charge compensation approaches are synthesized by a high-temperature solid-state reaction method, and the luminescent properties and Commission Internationale de l'Eclairage (CIE) chromaticity coordinates are systematically characterized. Ca2BO3Cl:Tb3+ can produce green emission under 376 nm radiation excitation. With codoped A+ (A = Li, Na, K) as charge compensators, the relative emission intensities of Ca2BO3Cl:Tb3+ are enhanced by about 1.61, 1.97, and 1.81 times compared with those of the direct charge balance, which is considered to be due to the effect of the difference in ion radius on the crystal field. The CIE chromaticity coordinates of Ca2BO3Cl:Tb3+, A+ (A = Li, Na, K) are (0.335, 0.584), (0.335, 0.585), and (0.335, 0.585), corresponding to the hues of green. Therefore, A+ (A = Li, Na, K) may be the optimal charge compensator for Ca2BO3Cl:Tb3+. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. The approach to chaos in ultracold atomic and molecular physics: statistics of near-threshold bound states for Li+CaH and Li+CaF

    CERN Document Server

    Frye, Matthew D; Vaillant, Christophe L; Green, Dermot G; Hutson, Jeremy M

    2015-01-01

    We calculate near-threshold bound states for the highly anisotropic systems Li+CaH and Li+CaF and perform statistical analysis on the resulting level positions to compare with the predictions of random matrix theory. For Li+CaH with total angular momentum $J=0$ we find fully chaotic behavior in both the nearest-neighbor spacing distribution and the level number variance. However, for $J>0$ we find different behavior due to the presence of a nearly conserved quantum number. Li+CaF ($J=0$) also shows apparently reduced levels of chaotic behavior despite its stronger effective coupling. We suggest this may indicate the development of another good quantum number relating to a bending motion of the complex. However, continuously varying the rotational constant over a wide range shows unexpected structure in the degree of chaotic behavior, including a dramatic reduction around the rotational constant of CaF. This demonstrates the complexity of the relationship between coupling and chaotic behaviour.

  2. Synthesis and Performance of LiMnO2 as Cathodes for Li-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shi-xi; LIU Han-xing; OUYANG Shi-xi; LI Qiang

    2003-01-01

    Two structure types of LiMnO2 were synthesized by sol-gel method and ion-exchange method respectively.The results indicate that orthorhombic phase LiMnO2 is more stable than layered LiMnO2,o-LiMnO2 can be synthesized directly by sol-gel methods followed by heat-treated in argon,but layered LiMnO2 was obtained only by indirect methods such as ion-exchange method.In this paper,we first synthesized layered NaMnO2 by the sol-gel method,and then obtained layered LiMnO2 by the ion-exchange method.The phase constitution,chemical composition,and images of the products were tested by XRD,AAS (atomic absorption spectroscopy) and SEM.The electrochemical performances of the two structural types of LiMnO2 are obviously different during the initial few cycles,but later they both have a good capacity-retaining ability.The capacity of layered structure LiMnO2 is higher than that of o-LiMnO2.

  3. S-wave and p-wave scattering in a cold gas of Na and Rb atoms

    CERN Document Server

    Ouerdane, H

    2008-01-01

    Using improved experimentally based $X{}^1\\Sigma^+$ and $a{}^3\\Sigma^+$ molecular potentials of NaRb, published recently by Pashov {\\it et al.} [Phys. Rev. A {\\bf 72}, 062505 (2005)], we apply the variable phase method to compute new data for low energy scattering of $^{23}$Na atoms by $^{85}$Rb atoms and $^{87}$Rb atoms. These are scattering lengths and volumes, numbers of bound states and effective ranges. From an analysis of the contributions of s-wave and p-wave scatterings to the elastic cross section we estimate temperatures below which only s-wave scattering is dominant. We supply evidence for the existence of a near zero energy p-wave bound state supported by the singlet molecular potential.

  4. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  5. Surface Passivation of MoO3 Nanorods by Atomic Layer Deposition Towards High Rate Durable Li Ion Battery Anodes

    KAUST Repository

    Ahmed, Bilal

    2015-06-03

    We demonstrate an effective strategy to overcome the degradation of MoO3 nanorod anodes in Lithium (Li) ion batteries at high rate cycling. This is achieved by conformal nanoscale surface passivation of the MoO3 nanorods by HfO2 using atomic layer deposition (ALD). At high current density such as 1500 mA/g, the specific capacity of HfO2 coated MoO3 electrodes is 68% higher than bare MoO3 electrodes after 50 charge/discharge cycles. After 50 charge/discharge cycles, HfO2 coated MoO3 electrodes exhibited specific capacity of 657 mAh/g, on the other hand, bare MoO3 showed only 460 mAh/g. Furthermore, we observed that HfO2 coated MoO3 electrodes tend to stabilize faster than bare MoO3 electrodes because nanoscale HfO2 layer prevents structural degradation of MoO3 nanorods. Additionally, the growth temperature of MoO3 nanorods and the effect of HfO2 layer thickness was studied and found to be important parameters for optimum battery performance. The growth temperature defines the microstructural features and HfO2 layer thickness defines the diffusion coefficient of Li–ions through the passivation layer to the active material. Furthermore, ex–situ HRTEM, X–ray photoelectron spectroscopy (XPS), Raman spectroscopy and X–ray diffraction was carried out to explain the capacity retention mechanism after HfO2 coating.

  6. Theoretical atomic collision physics

    Energy Technology Data Exchange (ETDEWEB)

    Lane, N.F. (Rice Univ., Houston, TX (USA) Rice Univ., Houston, TX (USA). Quantum Inst.)

    1990-01-01

    The theoretical atomic physics at Rice University focuses on obtaining a better understanding of the mechanisms that control inelastic collisions between excited atoms and atoms, molecules and ions. Particular attention is given to systems and processes that are of potential importance to advanced energy technologies. In the current year, significant progress has been made in quantitative studies of: quenching of low-Rydberg Na atoms in thermal energy collisions with He, Ne and Ar atoms; selective excitation resulting from charge transfer in collisions of highly stripped ions of He, Li, C, and with Li, Na and He atoms and H{sub 2} molecules at keV energies; differential elastic and single, and double electron transfer in He{sup ++} collisions with He at keV energies; inelastic electron-transfer in ultra-low-energy-energy (T=8 to 80K) collisions between {sup 3}He{sup +} and {sup 4}He and {sup 4}He{sup +} and {sup 3}He; a formalism for ionization by electron impact of ions in dense, high temperature plasmas.

  7. Resonant collisions of Na nS and nD Rydberg atoms

    International Nuclear Information System (INIS)

    A large enhancement in the resonant collisional energy-transfer process Na(ns)+Na(ns) →Na[(n-1)p]+Na(nl) or Na(ns)+Na(ns)→Na(np)+Na[(n-1)l] is observed when the initial ns state lies midway between (n-1)p and an nl state or between np and an (n-1)l state. This resonance condition, achieved by the electric field tuning of the levels, leads to large cross sections approx.109 A2 and narrow linewidths approx.1 GHz. These cross sections and linewidths are comparable to the previously observed resonant process Na(ns)+Na(ns)→Na[(n-1)p]+Na (np). We have also observed a similar collisional energy transfer starting from a completely different initial state, i.e., Na(15d)+Na(15d)→Na(16f)+Na (15p). In this case the enhancement in the cross section (approx.108 A2) is observed at a relatively low electric field approx.17 V/cm

  8. Structure and properties of a rapidly solidified Al-Li-Mn-Zr Alloy for high-temperature applications: Part I. inert gas atomization processing

    Science.gov (United States)

    Ruhr, Michael; Baram, Joseph

    1991-10-01

    A new Al-Li alloy containing 2.3 wt pct Li, 6.5 wt pct Mn, and 0.65 wt pet Zr, for high-temperature applications, has been processed by a rapid solidification (RS) technique (as powders by inert gas atomization) and then thermomechanically treated by hot isostatic pressing (hipping) and hot extrusion. As-received and thermomechanically treated powders (of various size fractions) were characterized by X-ray diffraction and scanning and transmission electron microscopy (SEM and TEM, respectively). Phase analyses in the as-processed materials revealed the presence of two Mn phases (Al4Mn and Al6Mn), one Zr phase (Al3Zr), two Li phases (the stable AlLi and the metastable Al3Li), and the αAl solid solution with high excess in Mn solubility (up to close the nominal composition in the as-atomized powders). Extruded pieces were solutionized at 370 °C and 530 °C for various soaking times (2 to 24 hours). A variety of aging treatments was practiced to check for the optimal (for tensile properties) aging procedure, which was found to be the following: solutioning at 370 °C for 2 hours and water quenching + 1 pct mechanical stretching + one step aging at 120 °C for 3 hours. The mechanical properties, at room and elevated temperatures, of the “hipped” and hot extruded powders are compared following the optimal solutioning and aging treatments. The results indicate that Mn is indeed a favorable alloying element for rapidly solidified Al-Li alloys to retain about 85 to 95 pct of the room-temperature tensile properties even at 250 °C, though room-temperature strength is not satisfactory in itself. However, specific moduli are by 20 to 25 pet higher than those of the 2024 series duralumin-type alloys. Ductilities at room temperatures are in the low 1 to 2.5 pct range and show no improvement over other Al-Li alloys.

  9. Atoms

    International Nuclear Information System (INIS)

    Completed by recent contributions on various topics (atoms and the Brownian motion, the career of Jean Perrin, the evolution of atomic physics since Jean Perrin, relationship between scientific atomism and philosophical atomism), this book is a reprint of a book published at the beginning of the twentieth century in which the author addressed the relationship between atomic theory and chemistry (molecules, atoms, the Avogadro hypothesis, molecule structures, solutes, upper limits of molecular quantities), molecular agitation (molecule velocity, molecule rotation or vibration, molecular free range), the Brownian motion and emulsions (history and general features, statistical equilibrium of emulsions), the laws of the Brownian motion (Einstein's theory, experimental control), fluctuations (the theory of Smoluchowski), light and quanta (black body, extension of quantum theory), the electricity atom, the atom genesis and destruction (transmutations, atom counting)

  10. Effects of Laser Energy and Wavelength on the Analysis of LiFePO4 Using Laser Assisted Atom Probe Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Santhanagopalan, Dhamodaran; Schreiber, Daniel K.; Perea, Daniel E.; Martens, Rich; Janssen, Yuri; Kalifah, Peter; Meng, Ying S.

    2015-01-21

    The effects of laser wavelength (355 nm and 532 nm) and laser pulse energy on the quantitative accuracy of atom probe tomography (APT) examinations of LiFePO4 (LFP) are considered. A systematic investigation of ultraviolet (UV, 355 nm) and green (532 nm) laser assisted APT of LFP has revealed distinctly different behaviors. With the use of UV laser the major issue was identified as the preferential loss of oxygen (up to 10 at. %) while other elements (Li, Fe and P) were observed to be close to nominal ratios. Lowering the laser energy per pulse to 1 pJ increased the observed oxygen concentration to near its correct stoichiometry and was well correlated with systematically higher concentrations of 16O2+ ions. This observation supports the premise that lower laser energies lead to a higher probability of oxygen molecule ionization. Conversely, at higher laser energies the resultant lower effective electric field reduces the probability of oxygen molecule ionization. Green laser assisted field evaporation led to the selective loss of Li (~50% deficiency) and correct ratios of the remaining elements, including the oxygen concentration. The loss of Li is explained by selective dc evaporation of lithium between laser pulses and relatively negligible oxygen loss as neutrals during green-laser pulsing. Lastly, plotting of multihit events on a Saxey plot for the straight-flight path data (green laser only) revealed a surprising dynamic recombination process for some molecular ions mid-flight.

  11. Corrosion of alloys in a chloride molten salt (NaCl-LiCl) for solar thermal technologies

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Vidal, Judith C.; Tirawat, Robert

    2016-12-01

    Next-generation solar power conversion systems in concentrating solar power (CSP) applications require high-temperature advanced fluids in the range of 600-800 degrees C. Current commercial CSP plants use molten nitrate salt mixtures as the heat transfer fluid and the thermal energy storage (TES) media while operating with multiple hours of energy capacity and at temperatures lower than 565 degrees C. At higher temperatures, the nitrates cannot be used because they decompose. Molten chloride salts are candidates for CSP applications because of their high decomposition temperatures and good thermal properties; but they can be corrosive to common alloys used in vessels, heat exchangers, and piping at these elevated temperatures. In this article, we present the results of the corrosion evaluations of several alloys in eutectic 34.42 wt% NaCl - 65.58 wt% LiCl at 650-700 degrees C in nitrogen atmosphere. Electrochemical evaluations were performed using open-circuit potential followed by a potentiodynamic polarization sweep. Corrosion rates were determined using Tafel slopes and Faraday's law. A temperature increase of as little as 50 degrees C more than doubled the corrosion rate of AISI stainless steel 310 and Incoloy 800H compared to the initial 650 degrees C test. These alloys exhibited localized corrosion. Inconel 625 was the most corrosion-resistant alloy with a corrosion rate of 2.80+/-0.38 mm/year. For TES applications, corrosion rates with magnitudes of a few millimeters per year are not acceptable because of economic considerations. Additionally, localized corrosion (intergranular or pitting) can be catastrophic. Thus, corrosion-mitigation approaches are required for advanced CSP plants to be commercially viable.

  12. Direct Growth of Bismuth Film as Anode for Aqueous Rechargeable Batteries in LiOH, NaOH and KOH Electrolytes

    Directory of Open Access Journals (Sweden)

    Wenhua Zuo

    2015-10-01

    Full Text Available As promising candidates for next-generation energy storage devices, aqueous rechargeable batteries are safer and cheaper than organic Li ion batteries. But due to the narrow voltage window of aqueous electrolytes, proper anode materials with low redox potential and high capacity are quite rare. In this work, bismuth electrode film was directly grown by a facile hydrothermal route and tested in LiOH, NaOH and KOH electrolytes. With low redox potential (reduction/oxidation potentials at ca. −0.85/−0.52 V vs. SCE, respectively and high specific capacity (170 mAh·g−1 at current density of 0.5 A·g−1 in KOH electrolyte, Bi was demonstrated as a suitable anode material for aqueous batteries. Furthermore, by electrochemical impedance spectroscopy (EIS analysis, we found that with smaller Rs and faster ion diffusion coefficient, Bi electrode film in KOH electrolyte exhibited better electrochemical performance than in LiOH and NaOH electrolytes.

  13. Influence of alkali metals (Na, Li, Rb) on the performance of electrostatic spray-assisted vapor deposited Cu2ZnSn(S,Se)4 solar cells

    Science.gov (United States)

    Altamura, Giovanni; Wang, Mingqing; Choy, Kwang-Leong

    2016-02-01

    Electrostatic Spray-Assisted Vapor Deposition (ESAVD) is a non-vacuum and cost-effective method to deposit metal oxide, various sulphide and chalcogenide at large scale. In this work, ESAVD was used to deposit Cu2ZnSn(S1-xSex)4 (CZTSSe) absorber. Different alkali metals like Na, Li and Rb were incorporated in CZTSSe compounds to further improve the photovoltaic performances of related devices. In addition, to the best of our knowledge, no experimental study has been carried out to test the effect of Li and Rb incorporation in CZTSSe solar cells. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and glow discharge spectroscopy have been used to characterize the phase purity, morphology and composition of as-deposited CZTSSe thin films. Photovoltaic properties of the resulting devices were determined by completing the solar cells as follows: Mo/CZTSSe/CdS/i-ZnO/Al:ZnO/Ni/Al. The results showed that Li, Na and Rb incorporation can increase power conversion efficiency of CZTS devices up to 5.5%. The introduction of a thiourea treatment, has improved the quality of the absorber|buffer interface, pushed the device efficiency up to 6.3% which is at the moment the best reported result for ESAVD deposited CZTSSe solar cells.

  14. Influence of alkali metals (Na, Li, Rb) on the performance of electrostatic spray-assisted vapor deposited Cu2ZnSn(S,Se)4 solar cells.

    Science.gov (United States)

    Altamura, Giovanni; Wang, Mingqing; Choy, Kwang-Leong

    2016-01-01

    Electrostatic Spray-Assisted Vapor Deposition (ESAVD) is a non-vacuum and cost-effective method to deposit metal oxide, various sulphide and chalcogenide at large scale. In this work, ESAVD was used to deposit Cu2ZnSn(S1-xSex)4 (CZTSSe) absorber. Different alkali metals like Na, Li and Rb were incorporated in CZTSSe compounds to further improve the photovoltaic performances of related devices. In addition, to the best of our knowledge, no experimental study has been carried out to test the effect of Li and Rb incorporation in CZTSSe solar cells. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and glow discharge spectroscopy have been used to characterize the phase purity, morphology and composition of as-deposited CZTSSe thin films. Photovoltaic properties of the resulting devices were determined by completing the solar cells as follows: Mo/CZTSSe/CdS/i-ZnO/Al:ZnO/Ni/Al. The results showed that Li, Na and Rb incorporation can increase power conversion efficiency of CZTS devices up to 5.5%. The introduction of a thiourea treatment, has improved the quality of the absorber(|)buffer interface, pushed the device efficiency up to 6.3% which is at the moment the best reported result for ESAVD deposited CZTSSe solar cells. PMID:26916212

  15. A new high sensitivity thermoluminescent phosphor with low residual signal and good stability to heat treatment: LiF:Mg,Cu,Na,Si

    International Nuclear Information System (INIS)

    The preliminary investigations are reported on the characteristics of a new, high-sensitivity thermoluminescence phosphor material (LiF:Mg,Cu,Na,Si) prepared in this laboratory. The main dosimetric peak of this phosphor occurs at 197 deg. C at a heating rate of 1 deg. C s-1. The glow curve shape shows minimal differences and sensitivity remains stable when annealed in the range from 250 to 280 deg. C for 10 min. Its TL sensitivity to gamma radiation is about 30 times higher than that of TLD-100 with a residual signal 0.2% following a 260 deg. C readout at a heating rate of 15 deg. C s-1. This negligible residual signal renders LiF;Mg,Cu,Na,Si usable in unannealed form. Its TL response at both 260 deg. C and 280 deg. C are reproducible within a coefficient of variation of 2% over ten re-use cycles without systematic decrease. It retains the main advantages of LiF:Mg,Cu,P phosphor, and has a lower residual signal and a better stability to heat treatment. (author)

  16. Laser-induced reversion of $\\delta^{'}$ precipitates in an Al-Li alloy: Study on temperature rise in pulsed laser atom probe

    CERN Document Server

    Khushaim, Muna; Al-Kassab, Talaat

    2015-01-01

    The influence of tuning the laser energy during the analyses on the resulting microstructure in a specimen utilizing an ultra-fast laser assisted atom probe was demonstrated by a case study of a binary Al-Li alloy. The decomposition parameters, such as the size, number density, volume fraction and composition of $\\delta^{'}$ precipitates, were carefully monitored after each analysis. A simple model was employed to estimate the corresponding specimen temperature for each value of the laser energy. The results indicated that the corresponding temperatures for the laser energy in the range of 10 to 80 pJ are located inside the miscibility gap of the binary Al-Li phase diagram and fall into the metastable equilibrium field. In addition, the corresponding temperature for a laser energy of 100 pJ was in fairly good agreement with reported range of $\\delta^{'}$ solvus temperature, suggesting a result of reversion upon heating due to laser pulsing.

  17. Enhanced Lithium Ion Transport by Superionic Pathways Formed on the Surface of Two-dimensional Structured Li0.85Na0.15V3O8 for High-Performance Lithium Ion Batteries

    International Nuclear Information System (INIS)

    Highlights: • Li0.85Na0.15V3O8 nanosheet with superionic conductive layer was constructed. • LixV2O5 surface layer provides facile pathways for lithium migration. • LixV2O5-Li0.85Na0.15V3O8 composite displays good high rate capability. - Abstract: Poor ion transport and rate capability are the main challenges for LiV3O8 as cathode material for lithium ion batteries. Here we report a novel strategy for enhancing lithium ion transport by building superionic pathways on the surface of Li0.85Na0.15V3O8 nanosheet. The two-dimensional Li0.85Na0.15V3O8 nanoparticle with an ion conductive layer of LixV2O5 on its surface is constructed by a modified sol–gel strategy with carefully controlled sodium incorporation and elements stoichiometry. Ultrathin LixV2O5 surface layer not only provides facile pathways for lithium migration, but also increases the structure stability during cycling. The LixV2O5-Li0.85Na0.15V3O8 composite displays good high rate capability of 172.3 mAh g−1 at 5C and excellent cycling stability of 98.9% over fifty cycles. This superior electrochemical property is attributed to the occupation of lithium site by Na+ in LiV3O8 host crystals and the surface superionic pathways of LixV2O5 phase. Therefore, the advantages of both high ion transport and the structure stabilization in present study put forward a new strategy for achieving high-performance LiV3O8 electrode material with tailored nanoarchitecture

  18. The compressibility mechanism of Li3Na3In2F12 garnet

    DEFF Research Database (Denmark)

    Grzechnik, Andrzej; Balic Zunic, Tonci; Makovicky, Emil;

    2006-01-01

    The high pressure behaviour of Li3Na3In2F12 garnet (Ia¯3d, Z = 8) is studied up to 9.2 GPa at room temperature in diamond anvil cells using xray diffraction. Its equation of state to 9.2 GPa and the pressure dependences of the structural parameters to 4.07 GPa are determined from synchrotron angle......-dispersive powder and laboratory single-crystal data, respectively. No indication of any structural phase transition in this material has been found up to 9.2 GPa. The fitting of the Murnaghan equation of state yields B0 = 36.2(5) GPa, B0 = 5.38(18), and V0 = 2051.76(0.69) °A 3. The compressibility mechanism of Li3...

  19. Theoretical study on the structure and dehydrogenation mechanism of mixed metal amidoborane, Na[Li(NH{sub 2}BH{sub 3})]{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kun; Zhang, Jian-Guo, E-mail: zjgbit@bit.edu.cn; He, Piao

    2013-12-25

    Highlights: •The systematic study of its structure and electronic structure in gas and solid phase. •The gas phase structures indicate that Li{sup +} cation and Na{sup +} cation acts as very different roles in the dehydrogenation. •Potential energy curves of dehydrogenation were obtained by CCSD(T) method. •Obtained the dehydrogenation rates similar to the experimental values. -- Abstract: This study is based on the synthesis of a mixed metal amidoborane, Na[Li(NH{sub 2}BH{sub 3})]{sub 2} (SLAB), the first example of an inorganic sodium–lithium compound. This paper is the first systematic study of its structure and dehydrogenation mechanism, and the results obtained were consistent with the experimental results. The first principle method was used to study the structure of SLAB in solid phase, while the second Moller–Plesset Perturbation Theory was used for gas-phase kinetic studies. Potential energy curves were obtained by CCSD(T) method. Three mechanistic pathways were designed to study its dehydrogenation, which include A pathway (without the cleavage of N–B bond (S and S′ pathways)), B pathway (with the cleavage of the intramolecular N–B bond before dehydrogenation), and D pathway (with the formation of direct dihydrogen bonds). Na{sup +} cation movement was proved to play a very important role in the hydrogen-transfer process. Finally, a possible dissociation pathway (A pathway) was confirmed and dehydrogenation rates similar to the experimental values were obtained.

  20. Investigation into the structure of ceramic Li{sub x}Na{sub 1-x}Ta{sub 0.1}Nb{sub 0.9}O{sub 3} solid solutions by X-ray analysis and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sidorov, N. V., E-mail: sidorov@chemy.kolasc.net.ru; Palatnikov, M. N.; Teplyakova, N. A.; Obryadina, E. Yu.; Alyoshina, L. A. [Russian Academy of Sciences, Tananaev Institute of Chemistry and Technology of Rare Earth Elements and Mineral Raw Materials, Kola Science Center (Russian Federation); Evdokimova, N. A.; Feklistova, E. P. [Petrozavodsk State University (Russian Federation)

    2013-07-15

    The structure of ceramic solid solutions Li{sub x}Na{sub 1-x}Ta{sub 0.1}Nb{sub 0.9}O{sub 3} has been investigated by full-profile X-ray diffraction analysis and Raman spectroscopy. It is shown that their structure for all x values is similar to the NaNbO{sub 3} structure. The structure of NaTa{sub 0.1}Nb{sub 0.9}O{sub 3} solid solutions (x = 0) is characterized by the sp. gr. Pbcm, and the structure of Li{sub x}Na{sub 1-x}Ta{sub 0.1}Nb{sub 0.9}O{sub 3} solid solutions with x = 0.05, 0.1, and 0.16 is characterized by the sp. gr. P2{sub 1}ma. The unit-cell parameters decrease with an increase in x. At x = 0, doubled values of the parameter c and, correspondingly, the unit-cell volume are observed in the antiferroelectric phase. This fact is confirmed by the form of the vibrational spectrum in the region of stretching modes of oxygen atoms along the polar axis.

  1. Measurements of atomic transition probabilities in highly ionized atoms by fast ion beams

    International Nuclear Information System (INIS)

    A summary is given of the beam-foil method by which level lifetimes and transition probabilities can be determined in atoms and ions. Results are presented for systems of particular interest for fusion research, such as the Li, Be, Na, Mg, Cu and Zn isoelectronic sequences. The available experimental material is compared to theoretical transition probabilities. (author)

  2. Physicochemical properties of the system (LiF + NaF + KF(eut.) + Na7Zr6F31): Phase equilibria, density and volume properties, viscosity and surface tension

    International Nuclear Information System (INIS)

    Highlights: • The investigated properties were studied in the entire concentration range. • Based on the thermal analysis and XRD the estimation of phase equilibria was deduced. • Density and viscosity increase with increasing content of Na7Zr6F31 in the system. • Surface tension decreases with increasing content of Na7Zr6F31 in the system. • Significant changes in concentration range (0 to 20) mol% of Na7Zr6F31 are discussed. - Abstract: The aims of the study were to investigate the physicochemical properties, such as the phase equilibria (by the means of thermal analysis), density (by Archimedean method of hydrostatic weighing), viscosity (by torsion pendulum method) and surface tension (by maximum bubble pressure method), of the (LiF + NaF + KF(eut.) + Na7Zr6F31) fluoride system. The obtained data show significant deviation from the ideal/additive behaviour, particularly in the concentration range from (0 to 20) mol% of Na7Zr6F31 while the data sets correspond each other very well. In this range a sharp increase in temperature of primary crystallisation together with volume expansion, positive deviation from “additive” behaviour of viscosity and negative deviation from “additive” behaviour of surface tension were observed. These significant changes are discussed and indicate complicated interactions of the components in the melt

  3. Complexing in the 1,10-phenanthroline-LiClO4 (NaClO4)-acetone system from the IR spectroscopy data

    International Nuclear Information System (INIS)

    Quantum-chemical calculations were made for optimized geometries, frequencies and normal vibration intensities of molecule 1,10-phenanthroline and sodium cations of 1:1 and 1:2 stoichiometry. The calculated data permitted reference of spectral components. Concentration changes in IR spectra of the system 1,10-phenanthroline-LiClO4 (NaClO4)-acetone-d6 were interpreted. Existence of 1:1 and 1:2 stoichiometry complexes in the systems was confirmed spectroscopically

  4. Investigation of heterogeneous equilibria in the system uranosilicate MHSiUO6·nH2O - aqueous solvent (M=Li, Na, K)

    International Nuclear Information System (INIS)

    State of mineral-like compounds of MHSiUO6·nH2O (M=Li, Na, K) composition in aqueous solutions at 298 K is investigated. Taking experimental data on solubility as a basis quantitative model of the system crystalline uranosilicate - aqueous solution is proposed. This model could be a basis for calculation of Gibbs formation functions and solubility product. Gibbs formation functions of silicic acid and other ionic-molecular forms of existence of Si(IV) in solution are calculated. Using the proposed model solubility of uranosilicates in aqueous solutions (in the region, which are not investigated experimentally) is forecasted

  5. Thermodynamic properties of aqueous ternary solutions relevant to chemical heat pumps: Final report. [LiNO/sub 3/-KNO/sub 3/-NaNO/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Ally, M.R.

    1987-03-01

    Polynomial expressions are developed that correlate experimental vapor-liquid-equilibrium (VLE) and specific enthalpy concentration data for a newly developed ternary absorption fluid (LiNO/sub 3/-KNO/sub 3/-NaNO/sub 3/). The development of these expressions are an important step toward using existing ORNL computer software to evaluate heat pump performance. A canned least-square-fit program, POLFIT.BAS, was invoked to obtain the polynomial coefficients. Results show that the maximum deviation between correlated and actual values is less than 3% for vapor pressure and enthalpy. This is considered sufficiently accurate for heat pump cycle performance studies.

  6. Quantum-chemical analysis of lithium, sodium, and potassium cations coordination with the dimethylsulfoxide molecules (MOH - H2O - DMSO, M = Li, Na, K)

    International Nuclear Information System (INIS)

    A model study of super base media in the MOH - H2O - DMSO systems (M=Li, Na, K; DMSO=dimethyl sulfoxide) is made using the Hartree-Fock quantum-chemical method within the 6-31 G(d) basis set. The structure and energy of the anion complexes formed in the systems are considered. It is shown that within the models in question, the hydroxide anion is stabilized in the form of two complexes, viz., OH-·H2O and OH-·2H2O

  7. Electrochemical reduction and electrocrystallization process of B(Ⅲ) in the LiF-NaF-KF-KBF4 molten salt

    Institute of Scientific and Technical Information of China (English)

    LI Jun; LI Bing

    2007-01-01

    The mechanisms of the electrochemical reduction and nucleation process of B(Ⅲ) on the platinum electrode in the LiF-NaF-KF-KBF4 molten salt at 700℃ were first investigated using cyclic voltammetry and chronoamperometry techniques.It was found that the electrochemical reduction of B(Ⅲ) occurs in single-step charge transfer: B(Ⅲ) + 3e → B,and the cathode process is reversible.The electrocrystallization process of B(Ⅲ) is instantaneous.

  8. Experimental determination of calcite solubility in H2O-KCl-NaCl-LiCl solutions at 700 °C and 8 kbar

    OpenAIRE

    Eguchi, James Hiro

    2014-01-01

    Understanding the interactions between calcite and aqueous solutions is important when studying the deep carbon cycle. The present study investigates the solubility of calcite in salt-H2O fluids at 700 °C and 8 kbar. The investigated salts included NaCl, KCl, LiCl, and CsCl. All experiments were conducted in a piston cylinder apparatus. The results show that calcite solubility increases with increasing concentration of any individual salt. The data were successfully fit to simple functions of...

  9. Hydrogen storage of a novel combined system of LiNH2-NaMgH3: synergistic effects of in situ formed alkali and alkaline-earth metal hydrides.

    Science.gov (United States)

    Li, Yongtao; Fang, Fang; Song, Yun; Li, Yuesheng; Sun, Dalin; Zheng, Shiyou; Bendersky, Leonid A; Zhang, Qingan; Ouyang, Liuzhang; Zhu, Min

    2013-02-01

    Bimetallic hydride NaMgH(3) is used for the first time as a vehicle to enhance hydrogen release and uptake from LiNH(2). The combination of NaMgH(3) with LiNH(2) at a molar ratio of 1 : 2 can release about 4.0 wt% of hydrogen without detectable NH(3) emission in the temperature range of 45 °C to 325 °C and exhibiting superior dehydrogenation as compared to individual NaH and/or MgH(2) combined with LiNH(2). A high capacity retention of about 75% resulting from the introduction of NaMgH(3) is also achieved in LiNH(2) as well as re-hydrogenation under milder conditions of 180 °C and 5 MPa H(2) pressure. These significant improvements are attributed to synergistic effects of in situ formed NaH and MgH(2)via the decomposition of NaMgH(3) where a succession of competing reactions from the cyclic consumption/recovery of NaH are involved and serve as a "carrier" for the ultra-rapid conveyance of the N-containing species between the [NH(2)](-) amide and the resulting [NH](2-) imide complexes. PMID:23165760

  10. LiCuS, an intermediate phase in the electrochemical conversion reaction of CuS with Li: A potential environment-friendly battery and solar cell material

    Science.gov (United States)

    Beleanu, Andreea; Kiss, Janos; Baenitz, Michael; Majumder, Mayukh; Senyshyn, Anatoliy; Kreiner, Guido; Felser, Claudia

    2016-05-01

    The crystal structure of a ternary sulfide with the approximate composition LiCuS, which is a promising candidate for environment-friendly battery and solar cell materials is reported. The crystal structure was solved by a combination of neutron and X-ray powder diffraction data, and 7Li solid-state NMR analysis. A yellow powder, Li1.1Cu0.9S, was obtained by the reaction of CuS with a slight excess of Li metal. The compound crystallizes in the Na3AgO2 structure type in the space group Ibam. An idealized crystal structure of Li1.1Cu0.9S can be derived from the cubic Li2S structure by moving a part of the Li along the c axis so that these Li atoms become linearly coordinated by S. All the metal sites are occupied by randomly mixed Li and Cu atoms; however, there is a strong preference for linear coordination by Cu. The density functional theory calculations show that Li1.1Cu0.9S is a direct band-gap semiconductor with an energy gap of 1.95 eV in agreement with experimental data.

  11. High-temperature corrosion behavior of Ni–16Mo–7Cr–4Fe superalloy containing yttrium in molten LiF–NaF–KF salt

    International Nuclear Information System (INIS)

    Highlights: • Traces of yttrium were doped in Ni–16Mo–7Cr–4Fe nickel-base superalloy. • High-temperature corrosion resistance is improved by proper yttrium addition. • Synchrotron radiation X-ray fluorescence with high sensitivity was adopted. - Abstract: The corrosion tests of a Ni–16Mo–7Cr–4Fe superalloy containing various yttrium contents were performed in molten FLiNaK (LiF–NaF–KF: 46.5–11.5–42 mol%) salt at 850 °C for 620 h, with the goals of investigating the effects of yttrium on the corrosion resistance of Ni–16Mo–7Cr–4Fe alloy and understanding the corrosion mechanisms. The addition of an appropriate amount of yttrium promotes the formation of a Y-rich layer near the surface and inhibits the diffusion of the susceptive elements

  12. High-temperature corrosion behavior of Ni–16Mo–7Cr–4Fe superalloy containing yttrium in molten LiF–NaF–KF salt

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiao-li; He, Shang-ming, E-mail: heshangming@sinap.ac.cn; Zhou, Xing-tai; Huai, Ping; Li, Zhi-jun; Li, Ai-guo; Yu, Xiao-han, E-mail: yuxiaohan@sinap.ac.cn

    2015-09-15

    Highlights: • Traces of yttrium were doped in Ni–16Mo–7Cr–4Fe nickel-base superalloy. • High-temperature corrosion resistance is improved by proper yttrium addition. • Synchrotron radiation X-ray fluorescence with high sensitivity was adopted. - Abstract: The corrosion tests of a Ni–16Mo–7Cr–4Fe superalloy containing various yttrium contents were performed in molten FLiNaK (LiF–NaF–KF: 46.5–11.5–42 mol%) salt at 850 °C for 620 h, with the goals of investigating the effects of yttrium on the corrosion resistance of Ni–16Mo–7Cr–4Fe alloy and understanding the corrosion mechanisms. The addition of an appropriate amount of yttrium promotes the formation of a Y-rich layer near the surface and inhibits the diffusion of the susceptive elements.

  13. Recommended atomic data for collisional-radiative model of Li-like ions and gain calculation for Li-like Al ions in the recombining plasma

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, T. [Okayama Univ. (Japan). Faculty of Engineering; Kawachi, T.; Nishihara, K.; Fujimoto, T.

    1995-09-01

    We have assessed atomic data for lithium-like ions for the purpose of constructing a reliable collisional-radiative model. We show several examples of the atomic data for aluminum and oxygen ions, and comparison of data from several sources is done in detail. For ions with nuclear charge z, the scaling formulas and fitting parameters, which are based on the data of oxygen ions, are presented. By use of these data, we have constructed two collisional-radiative models: the one for aluminum ions and the one for ions according to the scaling for z. The population inversion and the amplification gain of the soft x-ray laser lines in the recombining aluminum plasma are calculated for several electron temperatures. We also examine the effects of ion collisions for {Delta}n=0 transitions on the excited level populations.

  14. Electron emission and exciton production of LiF surfaces by grazing impact of hydrogen neutral atoms

    International Nuclear Information System (INIS)

    We put forward an alternative mechanism to understand the physics underlying the electron emission and exciton formation occurring during grazing collision of neutral hydrogen on LiF(001) surfaces. Instead of visualizing the negative ion formation as the precursor, we propose the formation of excited H(n=2) as a catalyzer to produce excitons and electrons

  15. Growth structure, and electrophysical properties of single crystals of A2TiGeO5 (A = Li and Na)

    International Nuclear Information System (INIS)

    Monocrystals of Li2TiGeO5 (1) were grown by the method of solution-in-melt crystallization during lithium titanate-germanate solution cooling in mixed solvent containing 80 wt.% of Li2MoO4 and 20 wt.% of Li2WO4 in the temperature range 968-958 deg C at a rate of 0.05 deg/h. By the X-ray diffraction method crystal structure of 1 was refined: a = 6.614 (4), c 4.435 (4) A, sp.gr. P4/nmm, Z = 2, ρ(calcld.) = 3.67 g/cm3. The Li-O distances for centrally symmetric octahedrons of LiO6 lie in the range of 2.049 (1) - 2.545 (2) A. Ionic conductivity of crystal 1 measured in the range of temperatures 250-600 deg C is anisotropic: it equals 10-4-10-5 S/cm along axis a at 400 deg C, being 3-4 orders less along axis c

  16. Two-step resonance ionization spectroscopy of Na atomic beam using cw and pulsed lasers

    International Nuclear Information System (INIS)

    Two-step photoionization of sodium atomic beam has been carried out using a cw and a pulsed dye lasers. Sodium ions have been detected by a time of flight method in order to reduce background noise. With a proper power of the pulsed dye laser the sodium atomic beam has been irradiated by a resonant cw dye laser. The density of the sodium atomic beam is estimated to be 103 cm-3 at the ionization area. (author)

  17. β-Xenophyllite-type Na4Li0.62Co5.67Al0.71(AsO46

    Directory of Open Access Journals (Sweden)

    Riadh Marzouki

    2013-10-01

    Full Text Available The title compound, tetrasodium lithium cobalt aluminium hexa(orthoarsenate, was synthesized by a solid state reaction route. In the crystal structure, Co2+ ions are partially substituted by Al3+ in an octahedral environment [M1 with site symmetry 2/m; occupancy ratio Co:Al = 0.286 (10:0.714 (10]. The charge compensation is ensured by Li+ cations sharing a tetrahedral site with Co2+ ions [M2 with site symmetry 2; occupancy ratio Co:Li = 0.690 (5:0.310 (5]. The anionic unit is formed by two octahedra and three tetrahedra linked only by corners. The CoM1M2As2O19 units associate to an open three-dimensional framework containing tunnels propagating along the a-axis direction. One Na+ cation is located in the periphery of the tunnels while the other two are situated in the centres: all Na+ cations exhibit half-occupancy. The structure of the studied material is compared with those of various related minerals reported in the literature.

  18. Simultaneous desorption behavior of M borohydrides and Mg2FeH6 reactive hydride composites (M = Mg, then Li, Na, K, Ca)

    Science.gov (United States)

    Chaudhary, Anna-Lisa; Li, Guanqiao; Matsuo, Motoaki; Orimo, Shin-ichi; Deledda, Stefano; Sørby, Magnus H.; Hauback, Bjørn C.; Pistidda, Claudio; Klassen, Thomas; Dornheim, Martin

    2015-08-01

    Combinations of complex metal borohydrides ball milled with the transition metal complex hydride, Mg2FeH6, are analysed and compared. Initially, the Reactive Hydride Composite (RHC) of Mg2+ cation mixtures of Mg2FeH6 and γ-Mg(BH4)2 is combined in a range of molar ratios and heated to a maximum of 450 °C. For the molar ratio of 6 Mg2FeH6 + Mg(BH4)2, simultaneous desorption of the two hydrides occurred, which resulted in a single event of hydrogen release. This single step desorption occurred at temperatures between those of Mg2FeH6 and γ-Mg(BH4)2. Keeping this anionic ratio constant, the desorption behavior of four other borohydrides, Li-, Na-, K-, and Ca-borohydrides was studied by using materials ball milled with Mg2FeH6 applying the same milling parameters. The mixtures containing Mg-, Li-, and Ca-borohydrides also released hydrogen in a single event. The Mass Spectrometry (MS) results show a double step reaction within a narrow temperature range for both the Na- and K-borohydride mixtures. This phenomenon, observed for the RHC systems at the same anionic ratio with all five light metal borohydride mixtures, can be described as simultaneous hydrogen desorption within a narrow temperature range centered around 300 °C.

  19. A3V2(PO4)3 (A = Na or Li) probed by in situ X-ray absorption spectroscopy

    Science.gov (United States)

    Pivko, Maja; Arcon, Iztok; Bele, Marjan; Dominko, Robert; Gaberscek, Miran

    2012-10-01

    Two stable modifications of A3V2(PO4)3 (A = Na or Li) were synthesized by citric acid assisted modified sol-gel synthesis. The obtained samples were phase pure Li3V2(PO4)3 and Na3V2(PO4)3 materials embedded in a carbon matrix. The samples were tested as half cells against lithium or sodium metal. Both samples delivered about 90 mAh g-1 at a C/10 cycling rate. The change of vanadium oxidation state and changes in the local environment of redox center for both materials were probed by in-situ X-ray absorption spectroscopy. Oxidation state of vanadium was determined by energy shift of the absorption edge. The reversible change of valence from trivalent to tetravalent oxidation state was determined in the potential window used in our experiments. Small reversible changes in the interatomic distances due to the relaxation of the structure in the process of alkali metal extraction and insertion were observed. Local environment (vanadium-oxygen bond distances) after 1st cycle were found to be the same as in the starting material. Both structures have been found very rigid without significant changes during alkali metal extraction.

  20. Experimental search for the permanent electric dipole moment of an Na atom using special capacitor in the shape of Dewar flask

    CERN Document Server

    You, Pei-Lin

    2010-01-01

    Since the time of Rutherford it was commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, so that all kinds of atoms do not have permanent electric dipole moment (EDM). In the fact, the idea is untested hypothesis. Using two special capacitors containing Sodium vapor we find the electric susceptibility Xe of Na atoms is directly proportional to its density N, and inversely to the absolute temperature T, as polar molecules. Xe=A+B/T, where A is approximately to zero, B=126.6 (K) and N=1.49*1020 m-3. A ground state neutral Na atom has a large permanent EDM: d( Na)=1.28*10-8e.cm. The non-zero observation of EDM in any non-degenerate system will be a direct proof of time-reversal violation in nature, and new example of CP violation occurred in Na atoms. We work out the most linear Stark shift of Na atoms is only 0.0033nm, and so its linear Stark effect has not been observed till now! The experimental Na material with purity 0.9995 is supplied by Strem Chemic...

  1. Order of oxygen and fluorine in the oxyfluorides Na/sub 2/WO/sub 2/F/sub 4/, LiW/sub 3/O/sub 9/F, and NaMoO/sub 3/F

    Energy Technology Data Exchange (ETDEWEB)

    Chaminade, J.P.; Moutou, J.M.; Villeneuve, G.; Couzi, M.; Pouchard, M.: Hagenmuller, P.

    1986-11-01

    Crystal structures of complex oxyfluorides Na/sub 2/WO/sub 2/F/sub 4/, LiW/sub 3/O/sub 9/F, and NaMoO/sub 3/F have been previously determined by X-ray diffraction but without assigning the specific position of oxygen or fluorine. Using various techniques such as /sup 19/F nuclear magnetic resonance, Raman spectroscopy, electrostatic energy and site potential calculations, analysis of the local balance between charge of neighboring ions, clear evidence has been given of an ordered oxygen-fluorine distribution within the anionic sublattices which is proposed. The accuracy of each method used has been discussed for each phase.

  2. Klasar og klasaframtök. Hvernig getur klasaframtakið Álklasinn leitt til aukinnar samkeppnishæfni í áliðnaði á Íslandi?

    OpenAIRE

    Anna María Einarsdóttir 1965

    2016-01-01

    Áliðnaður ásamt þeirri orku sem hann notar er grunnatvinnuvegur á Íslandi. Um þessar mundir gengur áliðnaður í gegnum miklar breytingar sem tengjast verði á áli, en hægst hefur á vexti eftirspurnar eftir áli í Kína vegna þess að dregið hefur úr hagvexti þar í landi. Umframeftirspurn er eftir áli í heiminum utan Kína og ef Kínverjar hætta að auka framleiðsluna má búast við að markaðurinn verði fljótur að jafna sig. Samkeppnishæfni getur aukist þegar samlegðaráhrif verða af staðbundinni eða...

  3. Klasar og klasaframtök: Hvernig getur klasaframtakið Álklasinn leitt til aukinnar samkeppnishæfni í áliðnaði á Íslandi?

    OpenAIRE

    Anna María Einarsdóttir 1965

    2016-01-01

    Áliðnaður ásamt þeirri orku sem hann notar er grunnatvinnuvegur á Íslandi. Um þessar mundir gengur áliðnaður í gegnum miklar breytingar sem tengjast verði á áli, en hægst hefur á vexti eftirspurnar eftir áli í Kína vegna þess að dregið hefur úr hagvexti þar í landi. Umframeftirspurn er eftir áli í heiminum utan Kína og ef Kínverjar hætta að auka framleiðsluna má búast við að markaðurinn verði fljótur að jafna sig. Samkeppnishæfni getur aukist þegar samlegðaráhrif verða af staðbundinni eða...

  4. High-pressure crystallography and compression behavior of the alkali-scandium-germanate end-members LiScGe2O6 and NaScGe2O6

    International Nuclear Information System (INIS)

    Synthetic single-crystal samples of the monoclinic pyroxene-type compounds LiScGe2O6 and NaScGe2O6 have been investigated by means of in-situ high-pressure Raman spectroscopy and X-ray diffraction techniques. Crystal-structure investigations at hydrostatic high-pressure conditions were carried out in addition to 10−4 GPa measurements using the diamond-anvil cell technique up to ∼9.5 GPa. Both samples, LiScGe2O6 (space group P21/c, a=9.9999(8) Å, b=9.1040(2) Å, c=5.4610(2) Å, β=109.240(2)° at 10−4 GPa) and NaScGe2O6 (space group C2/c, a=10.1678(5) Å, b=9.1583(5) Å, c=5.5672(3) Å, β=107.257(3)° at 10−4 GPa), did not undergo any compression-induced change of symmetry as confirmed by single-crystal diffraction patterns. Series of high-pressure Raman spectra confirm the absence of any symmetry-related structural phase transition with band positions shifting in a smooth fashion on increasing pressure. High-precision lattice parameters, as determined from X-ray diffraction profile analyzes, were used to monitor both the compressibilities of lattice directions and the evolution of the unit-cell volume with pressure. The experimental data was fitted using a third-order Birch–Murnaghan equation-of-state approach and parameterized fits yield V0=469.60(11) Å3, K0=85.6(1.3) GPa and K′=5.9(4) for LiScGe2O6 and V0=495.95(19) Å3, K0=79(3) GPa and K′=3.9(1.1) for NaScGe2O6. The systematic comparison of volume properties and compression behavior shows that both pyroxene-type compounds follow established trend lines with similar slopes in comparing volumes versus bulk moduli, and confirm that the position of trend lines in this systematics describing variations with M1 critically depend on the type of M2 and T cations, independent on the space-group symmetry. - Graphical abstract: Polyhedral model of the LiScGe2O6 crystal structure at 9.51 GPa. Red and blue: crystallographic distinctive germanium-tetrahedral chains; Green: scandium-octahedral chains; Purple

  5. High-pressure crystallography and compression behavior of the alkali-scandium-germanate end-members LiScGe{sub 2}O{sub 6} and NaScGe{sub 2}O{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Hofer, Gregor [Institut für Mineralogie und Kristallographie, Universität Wien, Althanstrasse 14, A-1090 Wien (Austria); Labor für Kristallographie, Eidgenössisch-Technische Hochschule Zürich, Vladimir-Prelog-Weg 1-5/10, CH-8093 Zürich (Switzerland); Kuzel, Johann; Scheidl, Katharina S. [Institut für Mineralogie und Kristallographie, Universität Wien, Althanstrasse 14, A-1090 Wien (Austria); Redhammer, Günther [Fachbereich Materialforschung und Physik, Universität Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg (Austria); Miletich, Ronald, E-mail: ronald.miletich-pawliczek@univie.ac.at [Institut für Mineralogie und Kristallographie, Universität Wien, Althanstrasse 14, A-1090 Wien (Austria)

    2015-09-15

    Synthetic single-crystal samples of the monoclinic pyroxene-type compounds LiScGe{sub 2}O{sub 6} and NaScGe{sub 2}O{sub 6} have been investigated by means of in-situ high-pressure Raman spectroscopy and X-ray diffraction techniques. Crystal-structure investigations at hydrostatic high-pressure conditions were carried out in addition to 10{sup −4} GPa measurements using the diamond-anvil cell technique up to ∼9.5 GPa. Both samples, LiScGe{sub 2}O{sub 6} (space group P2{sub 1}/c, a=9.9999(8) Å, b=9.1040(2) Å, c=5.4610(2) Å, β=109.240(2)° at 10{sup −4} GPa) and NaScGe{sub 2}O{sub 6} (space group C2/c, a=10.1678(5) Å, b=9.1583(5) Å, c=5.5672(3) Å, β=107.257(3)° at 10{sup −4} GPa), did not undergo any compression-induced change of symmetry as confirmed by single-crystal diffraction patterns. Series of high-pressure Raman spectra confirm the absence of any symmetry-related structural phase transition with band positions shifting in a smooth fashion on increasing pressure. High-precision lattice parameters, as determined from X-ray diffraction profile analyzes, were used to monitor both the compressibilities of lattice directions and the evolution of the unit-cell volume with pressure. The experimental data was fitted using a third-order Birch–Murnaghan equation-of-state approach and parameterized fits yield V{sub 0}=469.60(11) Å{sup 3}, K{sub 0}=85.6(1.3) GPa and K′=5.9(4) for LiScGe{sub 2}O{sub 6} and V{sub 0}=495.95(19) Å{sup 3}, K{sub 0}=79(3) GPa and K′=3.9(1.1) for NaScGe{sub 2}O{sub 6}. The systematic comparison of volume properties and compression behavior shows that both pyroxene-type compounds follow established trend lines with similar slopes in comparing volumes versus bulk moduli, and confirm that the position of trend lines in this systematics describing variations with M1 critically depend on the type of M2 and T cations, independent on the space-group symmetry. - Graphical abstract: Polyhedral model of the LiScGe{sub 2}O{sub 6

  6. JE LI NAM POTREBNA TARIFA REVIZIJSKIH USLUGA - OSVRT NA POSTOJEĆE STANJE I PERSPEKTIVE U BUDUĆNOSTI

    OpenAIRE

    Zenzerović, Robert

    2012-01-01

    Svrha rada jest ukazati na prijeko potrebna unapređenja kvalitete revizije financijskih izvještaja u Republici Hrvatskoj uspostavom minimalne cijene revizije u okviru tarife koja bi rezultirala zaustavljanjem degradacije revizije kao profesije. Glavni je cilj u funkciji svrhe istraživanja, a to je utvrditi determinante revizijskih naknada u Republici Hrvatskoj i analizirati razlike zaračunatih naknada u odnosu na visinu naknada koje bi bile zaračunate da je na snazi tarifa revizijskih usluga....

  7. Collisional stability of localized Yb(${}^3\\mathrm{P}_2$) atoms immersed in a Fermi sea of Li

    CERN Document Server

    Konishi, Hideki; Ueda, Shinya; Takahashi, Yoshiro

    2016-01-01

    We establish an experimental method for a detailed investigation of inelastic collisional properties between ytterbium (Yb) in the metastable ${}^3\\mathrm{P}_2$ state and ground state lithium (Li). By combining an optical lattice and a direct excitation to the ${}^3\\mathrm{P}_2$ state we achieve high selectivity on the collisional partners. Using this method we determine inelastic loss coefficients in collisions between $^{174}$Yb(${}^3\\mathrm{P}_2$) with magnetic sublevels of $m_J=0$ and $-2$ and ground state $^6$Li to be $(4.4\\pm0.3)\\times10^{-11}~\\mathrm{cm}^3/\\mathrm{s}$ and $(4.7\\pm0.8)\\times10^{-11}~\\mathrm{cm}^3/\\mathrm{s}$, respectively. Absence of spin changing processes in Yb(${}^3\\mathrm{P}_2$)-Li inelastic collisions at low magnetic fields is confirmed by inelastic loss measurements on the $m_J=0$ state. We also demonstrate that our method allows us to look into loss processes in few-body systems separately.

  8. Theoretical assessment of the electro-optical features of the group III nitrides (B12N12, Al12N12 and Ga12N12) and group IV carbides (C24, Si12C12 and Ge12C12) nanoclusters encapsulated with alkali metals (Li, Na and K)

    Science.gov (United States)

    Tahmasebi, Elham; Shakerzadeh, Ehsan; Biglari, Zeinab

    2016-02-01

    Density functional theory (DFT) calculations have been carried out to study the influence of alkali metals (Li, Na and K) encapsulation within the group III nitrides (B12N12, Al12N12 and Ga12N12) and the group IV carbides (C24, Si12C12and Ge12C12) nanoclusters. The encapsulation of Li, Na and K atoms is found to narrow the HOMO-LUMO gaps of the considered clusters. The electronic properties of these clusters, especially the group III nitrides nanoclusters, are strongly sensitive to interaction with the alkali metals. Moreover it is observed that the encapsulation of alkali metals enhances the first hyperpolarizabilities of B12N12 nanocluster. Surprisingly, due to the alkali metals encapsulation within B12N12 nanocluster, the first hyperpolarizability values are remarkably increased to 8505.49 and 122,503.76 a.u. for Na@B12N12 and K@B12N12, respectively. Also the TD-DFT calculations at both CAM-B3LYP/6-311+G(d) and PBE0/6-311+G(d) levels of theory are also performed to investigate the origin of first hyperpolarizabilities.

  9. Asymptotics-based CI models for atoms:Properties, exact solution of a minimal model for Li to Ne, and application to atomic spectra

    OpenAIRE

    Friesecke, G.; Goddard, B.D.

    2009-01-01

    Configuration-interaction (CI) models are approximations to the electronic Schrödinger equation which are widely used for numerical electronic structure calculations in quantum chemistry. Based on our recent closed-form asymptotic results for the full atomic Schrödinger equation in the limit of fixed electron number and large nuclear charge [SIAM J. Math. Anal., 41 (2009), pp. 631-664], we introduce a class of CI models for atoms which reproduce, at fixed finite model dimension, the correct S...

  10. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of 21Na with improved laser trapping techniques

    International Nuclear Information System (INIS)

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive 21Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of 21Na to the experiment. Efficient manipulation of the 21Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of 21Na. She measured the 3S1/2(F=1,m=0)-3S1/2(F=2,m=0) atomic level splitting of 21Na to be 1,906,471,870±200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms

  11. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of {sup 21}Na with improved laser trapping techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Mary A.

    1999-05-24

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive {sup 21}Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of {sup 21}Na to the experiment. Efficient manipulation of the {sup 21}Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of {sup 21}Na. She measured the 3S{sub 1/2}(F=1,m=0)-3S{sub 1/2}(F=2,m=0) atomic level splitting of {sup 21}Na to be 1,906,471,870{+-}200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.

  12. Pd nanoparticles on ZnO-passivated porous carbon by atomic layer deposition: an effective electrochemical catalyst for Li-O2 battery.

    Science.gov (United States)

    Luo, Xiangyi; Piernavieja-Hermida, Mar; Lu, Jun; Wu, Tianpin; Wen, Jianguo; Ren, Yang; Miller, Dean; Zak Fang, Zhigang; Lei, Yu; Amine, Khalil

    2015-04-24

    Uniformly dispersed Pd nanoparticles on ZnO-passivated porous carbon were synthesized via an atomic layer deposition (ALD) technique, which was tested as a cathode material in a rechargeable Li-O2 battery, showing a highly active catalytic effect toward the electrochemical reactions-in particular, the oxygen evolution reaction. Transmission electron microscopy (TEM) showed discrete crystalline nanoparticles decorating the surface of the ZnO-passivated porous carbon support in which the size could be controlled in the range of 3-6 nm, depending on the number of Pd ALD cycles performed. X-ray absorption spectroscopy (XAS) at the Pd K-edge revealed that the carbon-supported Pd existed in a mixed phase of metallic palladium and palladium oxide. The ZnO-passivated layer effectively blocks the defect sites on the carbon surface, minimizing the electrolyte decomposition. Our results suggest that ALD is a promising technique for tailoring the surface composition and structure of nanoporous supports for Li-O2 batteries. PMID:25829367

  13. SnO2 anode surface passivation by atomic layer deposited HfO2 improves li-ion battery performance

    KAUST Repository

    Yesibolati, Nulati

    2014-03-14

    For the first time, it is demonstrated that nanoscale HfO2 surface passivation layers formed by atomic layer deposition (ALD) significantly improve the performance of Li ion batteries with SnO2-based anodes. Specifically, the measured battery capacity at a current density of 150 mAg -1 after 100 cycles is 548 and 853 mAhg-1 for the uncoated and HfO2-coated anodes, respectively. Material analysis reveals that the HfO2 layers are amorphous in nature and conformably coat the SnO2-based anodes. In addition, the analysis reveals that ALD HfO2 not only protects the SnO2-based anodes from irreversible reactions with the electrolyte and buffers its volume change, but also chemically interacts with the SnO2 anodes to increase battery capacity, despite the fact that HfO2 is itself electrochemically inactive. The amorphous nature of HfO2 is an important factor in explaining its behavior, as it still allows sufficient Li diffusion for an efficient anode lithiation/delithiation process to occur, leading to higher battery capacity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Electrochemical investigation on the redox chemistry of niobium in LiCl-KCl-KF-Na2O melts

    DEFF Research Database (Denmark)

    Gillesberg, Bo; Bjerrum, Niels; Barner, Jens H. Von;

    1997-01-01

    The system LiCl-KCl-KF-1 mole percent K2NbF7 (molar ration F-/Nb = 8) has been investigated in-the temperature range 370 to 725 degrees C by cyclic and square wave voltammetry. In the temperature range from 370 to 520 degrees C Nb(V) was reduced to Nb(III) in two reversible steps: Nb(V) --> Nb(IV...

  15. Two-stage magneto-optical trapping and narrow-line cooling of $^6$Li atoms to high phase-space density

    CERN Document Server

    Sebastian, Jimmy; Li, Ke; Gan, Huat Chai Jaren; Li, Wenhui; Dieckmann, Kai

    2014-01-01

    We report an experimental study of peak and phase-space density of a two-stage magneto-optical trap (MOT) of 6-Li atoms, which exploits the narrower $2S_{1/2}\\rightarrow 3P_{3/2}$ ultra-violet (UV) transition at 323 nm following trapping and cooling on the more common D2 transition at 671 nm. The UV MOT is loaded from a red MOT and is compressed to give a high phase-space density up to $3\\times 10^{-4}$. Temperatures as low as 33 $\\mu$K are achieved on the UV transition. We study the density limiting factors and in particular find a value for the light-assisted collisional loss coefficient of $1.3 \\pm0.4\\times10^{-10}\\,\\textrm{cm}^3/\\textrm{s}$ for low repumping intensity.

  16. Trajectory dependent energy loss in grazing collisions of keV He atoms from a LiF(0 0 1) surface

    International Nuclear Information System (INIS)

    Angular distributions for scattering of 12 keV He atoms from a LiF(0 0 1) surface under a grazing angle of incidence were recorded in coincidence with the projectile energy loss and the number of electrons emitted from the target surface during the collision. For scattering along the low indexed 〈1 1 0〉 and 〈1 0 0〉 directions of the crystal surface collisional rainbow peaks were observed. For scattering along a 〈1 1 0〉 direction the resulting rainbow peaks can be attributed to scattering from strings of anions which form active sites for charge exchange and emission of electrons. The data can be interpreted by trajectory computer simulations where charge transfer takes place from F− sites

  17. MIOPIJA I POROD. Smiju li umjerena i visoka miopija rodilje utjecati na način dovršenja poroda?

    OpenAIRE

    Petrović, Oleg; Prodan, Mirko; Lončarek, Karmen; Zaputović, Sanja; Sindik, Nebojša

    2009-01-01

    Cilj rada. Mnogi oftalmolozi i opstetričari još uvijek za dovršenje trudnoće odnosno poroda u žena s visokom miopijom preporučuju carski rez ili instrumentalni vaginalni porod, iako za to nema valjanih medicinskih dokaza. Budući da je u zdravstvenoj ustanovi autora došlo do promjene doktrine prema kojoj visoka miopija više nije predstavljala indikaciju za elektivni carski rez, cilj rada bio je istražiti je li spomenuta promjena imala ikakve implikacije glede zdravlja, osobito vida rodilje i p...

  18. Dielectric and piezoelectric properties of Bi0.5(Na0.82K0.18)0.5 TiO3–LiSbO3 lead-free piezoelectric ceramics

    Indian Academy of Sciences (India)

    Zhou Chong-Rong; Chai Li-Yuan

    2011-07-01

    The (1–)Bi0.5(Na0.82K0.18)0.5TiO3–LiSbO3 ( = 0−0.03) lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method and the effect of LiSbO3 addition on microstructure and electrical properties of the ceramics was investigated. The results of XRD measurement show that Li+ and Sb5+ diffuse into the Bi0.5(Na0.82K0.18)0.5TiO3 lattices to form a solid solution with a pure perovskite structure. The LiSbO3 addition has no remarkable effect on the crystal structure. However, a significant change in grain size took place. Simultaneously, with increasing amount of LiSbO3, the temperature for a antiferroelectric to paraelectric phase transition clearly increases. The piezoelectric constant 33 and the electromechanical coupling factor p show an obvious improvement by adding small amount of LiSbO3, which shows optimum values of 33 = 175 pC/N and p = 0.36 at = 0.01.

  19. Charging Induced Emission of Neutral Atoms from NaCl Nanocube Corners

    OpenAIRE

    Ceresoli, Davide; Zykova-Timan, Tatyana; Tosatti, Erio

    2008-01-01

    Detachment of neutral cations/anions from solid alkali halides can in principle be provoked by donating/subtracting electrons to the surface of alkali halide crystals, but generally constitutes a very endothermic process. However, the amount of energy required for emission is smaller for atoms located in less favorable positions, such as surface steps and kinks. For a corner ion in an alkali halide cube the binding is the weakest, so it should be easier to remove that atom, once it is neutral...

  20. Comparison of the hydrodynamic and Dirac models of the dispersion interaction between graphene and H, He${}^{\\ast}$, or Na atoms

    CERN Document Server

    Churkin, Yu V; Klimchitskaya, G L; Yurova, V A

    2010-01-01

    The van der Waals and Casimir-Polder interaction of different atoms with graphene is investigated using the Dirac model which assumes that the energy of quasiparticles is linear with respect to the momentum. The obtained results for the van der Waals coefficients of hydrogen atoms and molecules and atoms of metastable He${}^{\\ast}$ and Na as a function of separation are compared with respective results found using the hydrodynamic model of graphene. It is shown that, regardless of the value of the gap parameter, the Dirac model leads to much smaller values of the van der Waals coefficients than the hydrodynamic model. The experiment on quantum reflection of metastable He${}^{\\ast}$ and Na atoms on graphene is proposed which is capable to discriminate between the two models of the electronic structure of graphene. In this respect the parameters of the phenomenological potential for both these atoms interacting with graphene described by different models are determined.

  1. Preparation and characterization of phosphate glass system A2MnMP2O10 (A = Li, Na, K and (M = W, Mo

    Directory of Open Access Journals (Sweden)

    Moutataouia M.

    2013-09-01

    Full Text Available New materials based glassy phosphates and transition elements A2MnMP2O10 (A = Li, Na, K and (M = Mo, W were prepared by direct fusion of the mixture of the reactants followed by quenching in the air. Analysis by X-ray diffraction showed that the obtained materials are amorphous. Differential scanning calorimetry DSC was used to determine the glass transition (Tg and crystallization (Tc temperatures. The thermal stability of tungsten glasses is higher than that of molybdenum ones. Tungsten plays, certainly, a role of cross-linking polyphosphate groups by creating more covalent new bonds P-O-W and W-O-W. Moreover, it has been shown that lithium glasses are more stable than sodium and potassium, probably due to the potassium hygroscopy. Raman analysis confirms that the studied glasses have similar structures and the predominant structural units are PO4, P2O7 and MO6 polyhedra (M = W, Mo, Mn.

  2. The solubilities of BeO, MgO and CaO in molten LiF-NaF-KF eutectic

    International Nuclear Information System (INIS)

    The solubilities of BeO, MgO and CaO in molten LiF-NaF-KF eutectic were determined at the temperatures between 600 and 800 deg C. The dissolution equilibrium of these oxides was found to be reached after a week of equilibration at 600 deg C. The heat of solutions, ΔH, obtained were (2.89 ± 0.17) x 10-4, (2.72 ± 0.25) x 10-4 and (2.09 ± 0.21) x 10-4 J/mol for BeO, MgO and CaO, respectively. The solubilities were markedly affected by the residual oxide ion concentration in the eutectic. (author)

  3. ESTUDIO DEL EFECTO DE ISOTÓPO DE HIDRÓGENO EN LOS COMPLEJOS M–H•••H–F (M=Li, Na

    Directory of Open Access Journals (Sweden)

    Andrés Reyes

    2009-06-01

    Full Text Available Se estudió teóricamente el efecto de isotópo de hidrógeno sobre la geometría, la distribución de carga electrónica, la estabilidad relativa y la energía de formación de complejos lineales tipo M–X···Y–F y todos sus isotopólogos de hidrógeno (M=Li, Na; X, Y= H, D, T. Estos estudios fueron realizados con el paquete computacional APMO a un nivel de teoría Hartree-Fock electrónico y nuclear. Los resultados obtenidos están de acuerdo con resultados reportados por otros autores que usan métodos de estructura electrónica convencional.  

  4. Spectroscopic investigations of Cu2+ in Li2O–Na2O–B2O3–Bi2O3 glasses

    Indian Academy of Sciences (India)

    N Srinivasa Rao; M Purnima; Shashidhar Bale; K Siva Kumar; Syed Rahman

    2006-08-01

    Pure and copper doped glasses with composition, Li2O–(40–)Na2O–50B2O3–10Bi2O3, have been prepared over the range 0 < < 40. The electron paramagnetic resonance (EPR) spectra of Cu2+ ions of these glasses have been recorded in the X-band at room temperature. Spin Hamiltonian parameters have been calculated. The molecular bonding coefficients, 2 and 2, have been calculated by recording the optical absorption spectra in the wavelength range 200–1200 nm. It has been observed that the site symmetry around Cu2+ ions is tetragonally distorted octahedral. The density and glass transition temperature variation with alkali content shows non-linear behaviour. The IR studies show that the glassy system contains BO3 and BO4 units in the disordered manner.

  5. First principles and crystal field calculations of the spectral, structural and electric properties of (Na, Li)VSi2O6 clinopyroxenes crystals

    International Nuclear Information System (INIS)

    In the present paper we report on the results of theoretical modeling of the structural, spectral and electronic properties of (Na, Li)VSi2O6 clinopyroxenes crystals. At first, the semi-empirical model of crystal field theory, namely, the exchange charge model was employed for modeling the crystal field parameters (CFP), taking into account the effects of the covalent bond formation between the V3+ and O2– ions. The calculated CFP values were used for diagonalization of the crystal field Hamiltonian matrix in a complete basis set spanned by all 25 wave functions of the LS terms of the 3d2 electron configuration. The second approach, the ab initio density functional theory (DFT)-based calculations, was employed for the structural optimization, analysis of the band structure, density of the states and the pressure effects of the considered compounds. All obtained results are discussed and compared with available experimental data. (paper)

  6. Ali stanje lišajske flore že kaže na spremembo kakovosti zraka v Šaleški dolini po izgradnji čistilnih naprav v termoelektrarni Šoštanj?

    OpenAIRE

    Savšek, Simona; Ambrožič, Tomaž; Stopar, Bojan; Turk, Goran; Poličnik, Helena; Franc BATIČ

    2016-01-01

    Lišaje zaradi njihove specifične biologije pogosto uporabljamo kot bioindikatorje kvalitete zraka. Njihova steljka je brez pravih tkiv in organov, nimajo razvite kutikule in korenin. Vse, kar potrebujejo za svojo rast in razvoj, črpajo iz zraka. Epifitske lišaje uporabljamo za (1) sledenje vnosa težkih kovin v okolje, saj se težke kovine v njih kopičijo, ter (2) za sledenje splošne onesnaženosti zraka, saj lišaji na območjih večjega onesnaženja začnejo propadati. Na območju Šaleške doline smo...

  7. Band gap modification and ferroelectric properties of Bi{sub 0.5}(Na,K){sub 0.5}TiO{sub 3}-based by Li substitution

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Ngo Duc [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam); International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam); Hung, Vu Ngoc [International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam); Quyet, Nguyen Van [Hanautech Co., Ltd., 832, Tamnip-dong, Yuseong-gu, Daejeon (Korea, Republic of); Chung, Hoang Vu [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet street, Hanoi (Viet Nam); Dung, Dang Duc, E-mail: dung.dangduc@hust.edu.vn [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam)

    2014-01-15

    We report on the reduction of band gap in Bi{sub 0.5}(Na{sub 0.82-x}Li{sub x}K{sub 0.18}){sub 0.5}(Ti{sub 0.95}Sn{sub 0.05})O{sub 3} from 2.99 eV to 2.84 eV due to the substitutions of Li{sup +} ions to Na{sup +} sites. In addition, the lithium substitution samples exhibit an increasing of the maximal polarizations from 21.8 to 25.7 μC/cm{sup 2}. The polarization enhancement of ferroelectric and reduction of the band gaps are strongly related to the Li substitution concentration as evaluated via the electronegative between A-site and oxygen and tolerance factor. The results are promising for photovoltaic and photocatalytic applications.

  8. Preparation of phosphors AEu(MoO4)2 (A=Li, Na, K and Ag) by sol-gel method

    International Nuclear Information System (INIS)

    A series of double molybdates phosphors AEu(MoO4)2 (A=Li, Na, K and Ag) have been prepared by sol-gel method. Their crystal structure and luminescent properties have also been investigated in a comparable way. The crystallization processes of the phosphor precursors were characterized by X-ray diffraction (XRD) and thermogravimetry-differential thermal analysis (TG-DTA). Field emission scanning electron microscopy (FE-SEM) was also used to characterize the shape and size distribution of the phosphors. Samples except KEu(MoO4)2 showed tetragonal scheelite structure in the range of our experiments, and no phase transition appeared. Phosphor KEu(MoO4)2 possessed two structures, and the phase transition took place at about 800 C. All samples with high purity could be obtained at about 500 C for 5 hours, and they all showed intense red light peaked at 616 nm originated from 5D0→7F2 emission of Eu3+ under the excitation of 465 nm or 394 nm light. The excitation spectra of phosphors AEu(MoO4)2 (A = Li, Na, and K) are composed of a strong broad charge transfer (CT) band and some sharp lines, and the relative intensity of CT band, the two strongest absorption lines at 395 nm and 465 nm are comparative, so these three phosphors are good red phosphor candidates for violet or blue LEDs. For the excitation spectrum of phosphor AgEu(MoO4)2, intensities of CT band and the absorption line at 395 nm are much weaker than that of line at 465 nm, thus phosphor AgEu(MoO4)2 is only suit for GaN-based blue LED. (orig.)

  9. Li and Na storage behavior of bowl-like hollow Co3O4 microspheres as an anode material for lithium-ion and sodium-ion batteries

    International Nuclear Information System (INIS)

    Highlights: • A unique bowl-like hollow spherical Co3O4 structure is prepared through a simple, low-cost and mass-yield method. • Such a bowl-like hollow Co3O4 microsphere demonstrates extraordinary rate and cycling performance for Li-storage. • The sodium-storage behavior of Co3O4 is investigated for the first time. - Abstract: Bowl-like hollow Co3O4 microspheres are prepared via a simple and low-cost route by thermally treating Co-containing resorcinol-formaldehyde composites gel in air. Scanning electron microscopy, transmission electron microscope and N2 adsorption-desorption measurements demonstrate that these bowl-like hollow Co3O4 microspheres are composed of hollow inner cavities and outer shell walls (70 nm thickness), on which a considerable amount of mesopores centered around 5-17 nm size are distributed. When employed as the anode material for lithium-ion batteries, these bowl-like hollow Co3O4 microspheres exhibit extraordinary cycling performance (111% retention after 50 cycles owing to capacity rise), fairly high rate capacity (650 mAh g−1 at 5 C) and enhanced lithium storage capacity. Meanwhile, the Na-storage behavior of Co3O4 as an anode material of Na-ion batteries is initially investigated based on such a hollow structure and it exhibits similar feature of discharge/charge profiles and a high initial discharge capacity but relatively moderate capacity retention compared with the Li-storage performance

  10. A self-injected, diode-pumped, solid-state ring laser for laser cooling of Li atoms

    International Nuclear Information System (INIS)

    We have constructed a solid-state light source for experiments with laser cooled lithium atoms based on a Nd:Y V O4 ring laser with second-harmonic generation. Unidirectional lasing, an improved mode selection, and a high output power of the ring laser were achieved by weak coupling to an external cavity which contained the lossy elements required for single frequency operation. Continuous frequency tuning is accomplished by controlling two piezoelectric transducers (PZTs) in the internal and the external cavities simultaneously. The light source has been utilized to trap and cool fermionic lithium atoms into the quantum degenerate regime

  11. A self-injected, diode-pumped, solid-state ring laser for laser cooling of Li atoms

    Energy Technology Data Exchange (ETDEWEB)

    Miake, Yudai; Mukaiyama, Takashi, E-mail: muka@ils.uec.ac.jp [Institute for Laser Science, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); O’Hara, Kenneth M. [Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300 (United States); Gensemer, Stephen [CSIRO Manufacturing Flagship, Lindfield, NSW 2070 (Australia)

    2015-04-15

    We have constructed a solid-state light source for experiments with laser cooled lithium atoms based on a Nd:Y V O{sub 4} ring laser with second-harmonic generation. Unidirectional lasing, an improved mode selection, and a high output power of the ring laser were achieved by weak coupling to an external cavity which contained the lossy elements required for single frequency operation. Continuous frequency tuning is accomplished by controlling two piezoelectric transducers (PZTs) in the internal and the external cavities simultaneously. The light source has been utilized to trap and cool fermionic lithium atoms into the quantum degenerate regime.

  12. A self-injected, diode-pumped, solid-state ring laser for laser cooling of Li atoms

    Science.gov (United States)

    Miake, Yudai; Mukaiyama, Takashi; O'Hara, Kenneth M.; Gensemer, Stephen

    2015-04-01

    We have constructed a solid-state light source for experiments with laser cooled lithium atoms based on a Nd:Y V O4 ring laser with second-harmonic generation. Unidirectional lasing, an improved mode selection, and a high output power of the ring laser were achieved by weak coupling to an external cavity which contained the lossy elements required for single frequency operation. Continuous frequency tuning is accomplished by controlling two piezoelectric transducers (PZTs) in the internal and the external cavities simultaneously. The light source has been utilized to trap and cool fermionic lithium atoms into the quantum degenerate regime.

  13. The (Na,Li)FeGe2O6 clinopyroxene-type series: a temperature-dependent single-crystal X-ray diffraction and 57Fe Mössbauer spectroscopic study

    Science.gov (United States)

    Redhammer, Günther J.; Tippelt, Gerold

    2016-01-01

    Pyroxene-type compounds along the solid solution series LiFeGe2O6 ( P21/ c space group symmetry) and NaFeGe2O6 ( C2/ c) have been synthesized at 1273-1373 K and investigated by single-crystal X-ray diffraction at 298 K and between 105 and 298 K for Li0.4Na0.6FeGe2O6 in order to study structural variations associated with the chemical- and temperature-driven P21/ c ⇔ C2/ c phase transition. 57Fe Mössbauer spectroscopy, differential thermal analysis, and determination of thermal expansion coefficients from high-temperature powder X-ray diffraction data complete the investigations. The C2/ c phase is stabilized with increasing Na+ content and temperature, and the phase boundary is found at 789 K in pure LiFeGe2O6, decreasing to 109 K in the compound Li0.3Na0.7FeGe2O6. From the available data, a T- X structural phase diagram is constructed. The P21/ c ⇔ C2/ c phase transition is accompanied by distinct variations in lattice parameters, rearrangements in M2 site coordination as well as changes in tetrahedral site chain kinking. Also, chemical strain and the thermal expansion tensor change in size and orientation with Li+ by Na+ replacement. The study will provide a detailed description of the observed variations in bond lengths, bond angles, and distortion parameters.

  14. Phase development, densification and dielectric properties of (0.95-xNa0.5K0.5NbO3 - 0.05LiTaO3 - x LiSbO3 lead-free piezoelectric ceramics

    Directory of Open Access Journals (Sweden)

    Pornsuda Bomlai

    2008-08-01

    Full Text Available Lead-free piezoelectric ceramics in the system (0.95-x Na0.5K0.5NbO3 - 0.05LiTaO3 - x LiSbO3, x = 0-0.1, were synthesized by a reaction-sintering method. The effects of the content of LiSbO3, and the sintering temperature on phase-development, microstructure and dielectric properties of the samples were investigated. Additions of LiSbO3 produced a change in crystal system from orthorhombic to tetragonal. The additive reduced the temperature at which secondary recrystallisation occurred, and also affected average grain size and dielectric constant. A sintering temperature of 1050oC (for 2 h was the optimum for this system in order to achieve a high density and high dielectric constant. A maximum dielectric constant of 1510 was recorded for the x = 0.04 composition.

  15. Crystallization behavior of (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Cheng, Chih-Wei; Chang, Kuo-Ming [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.t [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao-Li 36003, Taiwan (China)

    2010-07-02

    The crystallization behavior of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED) and energy dispersive spectroscopy (EDS). The crystalline phase was composed of {beta}-spodumene. The isothermal crystallization kinetics of {beta}-spodumene from the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses has also been studied by a quantitative X-ray diffraction method. The activation energy of {beta}-spodumene formation decreases from 359.2 to 317.8 kJ/mol when the Na{sub 2}O content increases from 0 to 0.4 mol and it increases from 317.8 to 376.9 kJ/mol when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The surface nucleation and plate-like growth were dominant in the crystallization of the (1 - x)Li{sub 2}O.xNa{sub 2}O.Al{sub 2}O{sub 3}.4SiO{sub 2} glasses.

  16. The Correlation of the NA Measurements by Counting 28Si Atoms

    International Nuclear Information System (INIS)

    An additional value of the Avogadro constant was obtained by counting the atoms in isotopically enriched Si spheres. With respect to the previous determination, the spheres were etched and repolished to eliminate metal contaminations and to improve the roundness. In addition, all the input quantities—molar mass, lattice parameter, mass, and volume—were remeasured aiming at a smaller uncertainty. In order to make the values given in Andreas et al. [Metrologia 48, S1 (2011)] and Azuma et al. [Metrologia 52, 360 (2015)] usable for a least squares adjustment, we report about the estimate of their correlation

  17. High-energy X-ray powder diffraction and atomic-pair distribution-function studies of charged/discharged structures in carbon-hybridized Li2MnSiO4 nanoparticles as a cathode material for lithiumion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Moriya, Maki; Miyahara, Masahiko; Hokazono, Mana; Sasaki, Hirokazu; Nemoto, Atsushi; Katayama, Shingo; Akimoto, Yuji; Hirano, Shin-ichi; Ren, Yang

    2014-10-01

    The stable cycling performance with a high discharge capacity of similar to 190 mAh g(-1) in a carbon-hybridized Li2MnSiO4 nanostructured powder has prompted an experimental investigation of the charged/discharged structures using synchrotron-based and laboratory-based X-rays and atomic-pair distributionfunction (PDF) analyses. A novel method of in-situ spray pyrolysis of a precursor solution with glucose as a carbon source enabled the successful synthesis of the carbon-hybridized Li2(M)nSiO(4) nanoparticles. The XRD patters of the discharged (lithiated) samples exhibit a long-range ordered structure characteristic of the (beta) Li2MnSiO4 crystalline phase (space group Pmn2(1)) which dissipates in the charged (delithiated) samples. However, upon discharging the long-range ordered structure recovers in each cycle. The disordered structure, according to the PDF analysis, is mainly due to local distortions of the MnO4 tetrahedra which show a mean Mn-O nearest neighbor distance shorter than that of the long-range ordered phase. These results corroborate the notion of the smaller Mn3+/Mn4+ ionic radii in the Li extracted phase versus the larger Mn2+ ionic radius in Li inserted phase. Thus Li extraction/insertion drives the fluctuation between the disordered and the long-range ordered structures. (C) 2014 Elsevier B.V. All rights reserved.

  18. Atomic-spectrometric determination of lithium, sodium, potassium and strontium in high-pure scandium

    International Nuclear Information System (INIS)

    Determination of lithium, sodium and potassium in strontium by flame photometry with atomic-absorption spectrophotometer is described. Scandium effect on value of Li, K. Na analytical signal in flame is studied. It is shown, that the base understates analytical signals. Determination of strontium by flame photometry is impossible. Determination of strontium (1x10-13 kg/ml) by atomic-absorption method with electrothermal atomization is possible

  19. Analysis and manipulation of atomic and molecular collisions using laser light

    International Nuclear Information System (INIS)

    Optical collisions in a crossed beam experiment are examined for the atomic collision pairs LiHe, LiNe, NaNe. Differential cross sections are measured in order to probe the quality of quantum chemical calculated and spectroscopical determined molecular potentials. The linear polarization of the excitation laser is used to manipulate the contrast of the differential cross sections for NaNe. Using elliptical polarized light total control over the angular position and the contrast of the interference pattern is demonstrated. Differential cross sections for the collision pairs LiH2 and LiD2 show a pronounced oscillatory structure, which for the first time is observed for atom-molecule optical collisions. (orig.)

  20. Transition probabilities for lines of Cr II, Na II and Sb I by laser produced plasma atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Absolute transition probabilities for lines of Cr II, Na II and Sb I were determined by emission spectroscopy of laser induced plasmas. The plasma was produced focusing the emission of a pulsed Nd-Yag laser on solid samples containing the atom in study. The light arising from the plasma region was collected by and spectrometer. the detector used was a time-resolved optical multichannel analyzer (OMA III EG and G). The wavelengths of the measured transitions range from 2000 to 4100 A. The spectral resolution of the system was 0.2 A. The method can be used in insulators materials as Cl Na crystals and in metallic samples as Al-Cr and Sn-Sb alloys. To avoid self-absorption effects the alloys were made with low Sb or Cr content. Relative transition probabilities have been determined from measurements of emission-line intensities and were placed on an absolute scale by using, where possible, accurate experimental lifetime values form the literature or theoretical data. From these measurements, values for plasma temperature (8000-24000K), electron densities (approx 10 ''16 cm''-3) and self-absorption coefficients have been obtained

  1. Transition probabilities for lines of Cr II, Na II and Sb I by laser produced plasma atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Absolute transition probabilities for lines of CR II, Na II and Sb I were determined by emission spectroscopy of laser induced plasmas. the plasma was produced focusing the emission of a pulsed Nd-Yag laser on solid samples containing the atom in study. the light arising from the plasma region was collected by and spectrometer. the detector used was a time-resolved optical multichannel analyzer (OMA III EG and G). The wavelengths of the measured transitions range from 2000 sto 4100 A. The spectral resolution of the system was 0. 2 A. The method can be used in insulators materials as Cl Na crystals and in metallic samples as Al-Cr and Sn-Sn alloys. to avoid self-absorption effects the alloys were made with low Sb or Cr content. Relative transition probabilities have been determined from measurements of emission-line intensities and were placed on an absolute scale by using, where possible, accurate experimental lifetime values form the literature or theoretical data. From these measurements, values for plasma temperature (8000-24000 K), electron densities (∼∼ 10''16 cm ''-3) and self-absorption coefficients have been obtained. (Author) 56 refs

  2. New examples of metalloaromatic Al-clusters: (Al4M4)Fe(CO)3 (M=Li, Na and K) and (Al4M4)2Ni: Rationalization for possible synthesis

    CERN Document Server

    Datta, A; Datta, Ayan; Pati, Swapan K.

    2005-01-01

    Ab-initio calculations reveal that all-metal antiaromatic molecules like Al4M4 (M=Li, Na and K) can be stabilized in half-sandwich complex: (Al4M4)Fe(CO)3 and full-sandwich complexes of the type: (Al4M4)2Ni. The formation of the full-sandwich complex [(Al4M4)2Ni] from its organometallic precursor depends on the stability of the organic-inorganic hybrid (C4H4) Ni (Al4Li4).

  3. Core-core and core-valence correlation energy atomic and molecular benchmarks for Li through Ar

    International Nuclear Information System (INIS)

    We have established benchmark core-core, core-valence, and valence-valence absolute coupled-cluster single double (triple) correlation energies (±0.1%) for 210 species covering the first- and second-rows of the periodic table. These species provide 194 energy differences (±0.03 mEh) including ionization potentials, electron affinities, and total atomization energies. These results can be used for calibration of less expensive methodologies for practical routine determination of core-core and core-valence correlation energies

  4. Core-core and core-valence correlation energy atomic and molecular benchmarks for Li through Ar.

    Science.gov (United States)

    Ranasinghe, Duminda S; Frisch, Michael J; Petersson, George A

    2015-12-01

    We have established benchmark core-core, core-valence, and valence-valence absolute coupled-cluster single double (triple) correlation energies (±0.1%) for 210 species covering the first- and second-rows of the periodic table. These species provide 194 energy differences (±0.03 mEh) including ionization potentials, electron affinities, and total atomization energies. These results can be used for calibration of less expensive methodologies for practical routine determination of core-core and core-valence correlation energies. PMID:26646872

  5. Core-core and core-valence correlation energy atomic and molecular benchmarks for Li through Ar

    Energy Technology Data Exchange (ETDEWEB)

    Ranasinghe, Duminda S.; Frisch, Michael J.; Petersson, George A., E-mail: gpetersson@wesleyan.edu [Hall-Atwater Laboratories of Chemistry, Wesleyan University, Middletown, Connecticut 06459-0180 (United States)

    2015-12-07

    We have established benchmark core-core, core-valence, and valence-valence absolute coupled-cluster single double (triple) correlation energies (±0.1%) for 210 species covering the first- and second-rows of the periodic table. These species provide 194 energy differences (±0.03 mE{sub h}) including ionization potentials, electron affinities, and total atomization energies. These results can be used for calibration of less expensive methodologies for practical routine determination of core-core and core-valence correlation energies.

  6. Preparation and Electrochemical Characterization of Aluminium Liquid Battery Cells With Two Different Electrolytes (NaCl-BaCl2-AlF3-NaF and LiF-AlF3-BaF2).

    Science.gov (United States)

    Napast, Viktor; Moškon, Jože; Homšak, Marko; Petek, Aljana; Gaberšček, Miran

    2015-01-01

    The possibility of preparation of operating rechargeable liquid battery cells based on aluminium and its alloys is systematically checked. In all cases we started from aluminium as the negative electrode whereas as the positive electrode three different metals were tested: Pb, Bi and Sn. Two types of electrolytes were selected: Na(3)AlF(6) -AlF(3) - BaCl(2) - NaCl and Li(3)AlF(3) - BaF(2). We show that some of these combinations allowed efficient separation of individual liquid layers. The cells exhibited expected voltages, relatively high current densities and could be charged and discharged several times. The capacities were relatively low (120 mAh in the case of Al-Pb system), mostly due to unoptimised cell construction. Improvements in various directions are possible, especially by hermetically sealing the cells thus preventing salt evaporation. Similarly, solubility of aluminium in alloys can be increased by optimising the composition of positive electrode. PMID:26680707

  7. Electrothermal atomization atomic absorption spectrometric determination of trace metals in uranium-plutomium fuel materials

    International Nuclear Information System (INIS)

    Atomic absorption spectrometric methods using the electrothermal mode of atomization developed for the determination of Ag, Be, Ca, Cd, Cr, Co, Cu, Fe, Li, Mn, Na, Ni, Sn and Zn in (U, Pu) solution with 4% plutonium have been described. The carbon rod atomizer has been adapted for glove box operation to enable handling of plutonium containing solution samples. Multielement solution standards with graded concentrations of the analytes and fixed concentration of the matrix are used in the standardization process. Nanogram to sub-nanogram quantities of the analytes have been determined with a precision of better than 9% RSD using 5 μl of the sample aliquots. (orig.)

  8. Effect of the (n, α) Nuclear Reaction of B10 and Li6 on the Retention of Nuclear Recoil Atoms in Solids

    International Nuclear Information System (INIS)

    The increase of initial retention in reactor-irradiated solid cobaltic complexes, chromates and dichromates can be achieved by mixing the compounds with highly powdered boron compounds (α - annealing). The thermal neutron ''fission'' products of B10 and particularly the a-particles can penetrate the crystal lattice of the material under examination and by introducing defects into it help to recombine the recoil interstitials with their parent vacancies. Potassium chromate seems to increase the Cr51 retention up to 12% when it is bombarded by neutrons in mixtures with powdered boric acid. Ammonium chromate and potassium dichromate did not show any increase. Trisethylenediamine cobalt (III) nitrate in mixtures with ammonium hydrogen tetraborate showed an increase of retention about 15% for a dose given from the n,a reaction of 20 Mrad. Lithium carbonate was also used in mixtures with potassium chromate, dichromate and ammonium chromate. An increase of about 9% in retention was achieved in potassium chromate. Ammonium chromate in mixtures with lithium carbonate showed an increase of 3.5% due to the n,a reaction while potassium dichromate showed an increase of 2%. The introduction of defects by the products of the n, α reaction of B10 and Li6 affects the isothermal annealing, increasing the irregularities as the dose due to the ''fission'' products increases. The dose was calculated from the Q of the nuclear reaction, and it was assumed that all of it was absorbed by the lattice. By microscopic examinations the size of microcrystals of boron and lithium compounds was found to be about a few microns, which allowed the ''fission'' products to cross the parent lattice and come into the examined material. (author)

  9. Experimental studies of collisions of excited Li(4p) atoms with C2H4, C2H6, C3H8 and theoretical interpretation of the Li-C2H4 system

    International Nuclear Information System (INIS)

    Collisions of excited Li(4p) states with C2H4, C2H6 and C3H8 are studied experimentally using far-wing scattering state spectroscopy techniques. High-level ab initio quantum mechanical studies of the Li-C2H4 system are conducted to explain the results of the experiment for this system. The recent and present works indicate that knowledge of the internal structure of the perturber (C2H4, C2H6 and C3H8) is essential to fully understand the interaction between the metal and the hydrocarbon molecules. The ab initio calculation shows that the Li(4d) (with little probability under the experimental conditions) and the Li(4p) can be formed directly through the laser pumping. It also shows that the Li(4s) and Li(3d) states can be formed through an electronic diabatic coupling involving a radiationless process. However, the Li(3p), Li(3s) and Li(2p) states can only be formed through a secondary diabatic coupling which is a much less probable process than the primary one. The calculation limited to two C2v sections of the potential energy surfaces (PESs) shows peculiar multi-state crossings that we have never seen in other lithium complexes we studied

  10. Experimental search for the permanent electric dipole moment of an Na atom using special capacitor in the shape of Dewar flask

    OpenAIRE

    You, Pei-Lin

    2010-01-01

    Since the time of Rutherford it was commonly believed that with no electric field, the nucleus of an atom is at the centre of the electron cloud, so that all kinds of atoms do not have permanent electric dipole moment (EDM). In the fact, the idea is untested hypothesis. Using two special capacitors containing Sodium vapor we find the electric susceptibility Xe of Na atoms is directly proportional to its density N, and inversely to the absolute temperature T, as polar molecules. Xe=A+B/T, wher...

  11. Atomic Layer Deposited MoS2 as a Carbon and Binder Free Anode in Li-ion Battery

    International Nuclear Information System (INIS)

    Molybdenum sulfide is deposited by atomic layer deposition (ALD) using molybdenum hexacarbonyl and hydrogen sulfide. Film growth is studied using in-situ quartz crystal microbalance, ex-situ X-ray reflectivity and ellipsometry. Deposition chemistry is further investigated with in-situ Fourier transform infrared spectroscopy. Self-limiting nature of the reaction is observed, typical of ALD. Saturated growth rate of 2.5 Å per cycle at 170 °C is obtained. As-deposited films are found amorphous in nature. As-grown films are tested as lithium-ion battery anode under half cell configuration. Electrochemical charge-discharge measurements demonstrate a stable cyclic performance with good capacity retention. Discharge capacity of 851 mAh g−1 is obtained after 50 cycles which corresponds to 77% of capacity retention of the initial capacity

  12. The phase transformation and crystallization kinetics of (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses

    International Nuclear Information System (INIS)

    The phase transformation and crystallization kinetics of (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na2O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na2O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 ± 22.2 to 284.0 ± 10.8 kJ mol-1 when the Na2O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 ± 10.8 to 446.0 ± 23.2 kJ mol-1 when the Na2O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li2O-xNa2O-Al2O3-4SiO2 glasses.

  13. The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Li, Wang-Long [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Cheng, Chih-Wei [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-Kung Road, Kaohsiung 80782, Taiwan (China); Chang, Kuo-Ming; Chen, Yong-Feng [Department of Electrical Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Hsi, Chi-Shiung, E-mail: chsi@nuu.edu.tw [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China)

    2010-09-01

    The phase transformation and crystallization kinetics of (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses have been studied by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED) analysis. The crystallization temperature at the exothermic peak increases from 1171 to 1212 K when the Na{sub 2}O content increases from 0 to 0.6 mol. The crystalline phase is composed of spodumene crystallization when the Na{sub 2}O content increases from 0 to 0.6 mol. The activation energy of spodumene crystallization decreases from 444.0 {+-} 22.2 to 284.0 {+-} 10.8 kJ mol{sup -1} when the Na{sub 2}O content increases from 0 to 0.4 mol. Moreover, the activation energy increases from 284.0 {+-} 10.8 to 446.0 {+-} 23.2 kJ mol{sup -1} when the Na{sub 2}O content increases from 0.4 to 0.6 mol. The crystallization parameters m and n approach 2, indicating that the surface nucleation and two-dimensional growth are dominant in (1 - x)Li{sub 2}O-xNa{sub 2}O-Al{sub 2}O{sub 3}-4SiO{sub 2} glasses.

  14. Atomic layer deposited cobalt oxide: An efficient catalyst for NaBH{sub 4} hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Dip K.; Manna, Joydev; Dhara, Arpan; Sharma, Pratibha; Sarkar, Shaibal K., E-mail: shaibal.sarkar@iitb.ac.in [Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)

    2016-01-15

    Thin films of cobalt oxide are deposited by atomic layer deposition using dicobalt octacarbonyl [Co{sub 2}(CO){sub 8}] and ozone (O{sub 3}) at 50 °C on microscope glass substrates and polished Si(111) wafers. Self-saturated growth mechanism is verified by x-ray reflectivity measurements. As-deposited films consist of both the crystalline phases; CoO and Co{sub 3}O{sub 4} that gets converted to pure cubic-Co{sub 3}O{sub 4} phase upon annealing at 500 °C under ambient condition. Elemental composition and uniformity of the films is examined by x-ray photoelectron spectroscopy and secondary ion-mass spectroscopy. Both as-deposited and the annealed films have been successfully tested as a catalyst for hydrogen evolution from sodium borohydride hydrolysis. The activation energy of the hydrolysis reaction in the presence of the as-grown catalyst is found to be ca. 38 kJ mol{sup −1}. Further implementation of multiwalled carbon nanotube, as a scaffold layer, improves the hydrogen generation rate by providing higher surface area of the deposited catalyst.

  15. Synthesis and X-ray Powder Diffraction Characterization of A New Niobate Crystal NaBa2 Li0.6 Nb4.8 Zn0.2 O15

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new niobate compound was synthesized for the first time in Na2 O-BaO-Li2 O-ZnO-Nb2 O5 system by solid state reaction.The new compound was studied by X- ray diffraction, electron probe, X- ray microanalysis, chemical analysis and SEM.The result of X-ray powder diffraction shows that NaBa2 Li0.6 Nb4.8 Zn0.2 O15 belongs to orthorhombic tungsten bronze structure, with .space group Pba2 ( 32 ) and lattice parameters a =12.6115(2)(A), b = 12.4981 (2)(A), C = 3.9479(3)(A).The X-ray powder diffraction lines of the compound were well indexed.

  16. Synthesis and photoluminescence of Sm3+ doped alkali alkaline earth borate hosts NaBa4 (BO3)3 and LiSr4(BO3)3

    International Nuclear Information System (INIS)

    In this paper we report the photoluminescence of Sm3+ doped alkali alkaline borate hosts NaBa4 (BO3)3 and LiSr4 (BO3)3. For the synthesis of alkali alkaline borate hosts NaBa4 (BO3)3 and LiSr4 (BO3)3 doped with different concentrations of Sm3+ ions, we used the novel combustion technique. The phase purity of the hosts was confirmed by the powder XRD technique. The photoluminescence of the phosphors were carried out within 300 to 700 nm wavelength range. The phosphor shows intense orange red (602 nm) emission for near UV excitation. The FTIR spectra of the phase pure hosts have also been reported. (author)

  17. Study of NaCl:Mn{sup 2+} nanostructures in the Suzuki phase by optical spectroscopy and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mejía-Uriarte, E.V., E-mail: elsi.mejia@ccadet.unam.mx [Laboratorio de Fotónica de Microondas, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, AP 70-186, C.P. 04510, D.F. México (Mexico); Kolokoltsev, O. [Laboratorio de Fotónica de Microondas, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, AP 70-186, C.P. 04510, D.F. México (Mexico); Navarrete Montesinos, M. [Instituto de Ingeniería, Universidad Nacional Autónoma de México, D.F. México (Mexico); Camarillo, E.; Hernández A, J.; Murrieta S, H. [Instituto de Física, Universidad Nacional Autónoma de México, AP 20-364, C.P. 01000, D.F. México (Mexico)

    2015-04-15

    NaCl:Mn{sup 2+} nanostructures in the Suzuki phase have been studied by fluorescence (emission and excitation) spectroscopy and atomic force microscopy (AFM) as a function of temperature. The “as-grown” samples give rise to two broad emission bands that peak at 508 (green emission) and 610 nm (red emission). The excitation spectrum shows peaks at 227 nm and 232 nm for emission wavelengths at 508 nm and 610 nm, respectively. When the samples are heated continuously from room temperature up to 220 °C, the green emission (associated to the excitation peak at 227 nm) disappears at a temperature close to 120 °C, whilst only the red emission remains, which is characteristic of manganese ions. AFM images on the (0 0 1) surface (freshly cleaved) show several conformations of nanostructures, such as disks of 20–50 nm in diameter. Particularly, the images also reveal nanostructures with rectangular shape of ~280×160 nm{sup 2} and ~6 nm height; these are present only in samples with green emission associated to the Suzuki phase. Then, the evidence suggests that this topographic configuration might be related to the interaction with the first neighbors and the next neighbors, according to the configuration that has been suggested for the Suzuki phase. - Highlights: • NaCl:Mn{sup 2+} single crystals in the Suzuki phase contain rectangular nanostructures. • Double emission of manganese ions: green (508 nm) and red (610 nm) bands. • The excitation peak at 227 nm is attributed to rectangular nanostructures. • The green emission band associated to Suzuki phase is extinguished at 120 °C.

  18. A density functional theory study on size-dependent structures, stabilities, and electronic properties of bimetallic MnAgm (M=Na, Li; n + m ≤ 7) clusters

    Institute of Scientific and Technical Information of China (English)

    Sun Hao-Ran; Kuang Xiao-Yu; Li Yan-Fang; Shao Peng; Zhao Ya-Ru

    2012-01-01

    The equilibrium geometries,relative stabilities,and electronic properties of MnAgm(M=-Na,Li; n +-m ≤ 7) as well as pure Agn,Nan,Lin (n ≤ 7) clusters are systematically investigated by means of the density functional theory.The optimized geometries reveal that for 2 ≤ n ≤ 7,there are significant similarities in geometry among pure Agn,Nan,and Lin clusters,and the transitions from planar to three-dimensional configurations occur at n =7,7,and 6,respectively.In contrast,the first three-dimensional (3D) structures are observed at n + m =5 for both NanAgm and LinAgm clusters.When n + m ≥ 5,a striking feature is that the trigonal bipyramid becomes the main subunit of LinAgm.Furthermore,dramatic odd-even alternative behaviours are obtained in the fragmentation energies,secondorder difference energies,highest occupied and lowest unoccupied molecular orbital energy gaps,and chemical hardness for both pure and doped clusters.The analytic results exhibit that clusters with an even electronic configuration (2,4,6) possess the weakest chemical reactivity and more enhanced stability.

  19. Improving luminescent property of SrIn2O4:Eu3+ by co-doped A+ (A =Li, Na, K) or Sm3+*

    Institute of Scientific and Technical Information of China (English)

    Wang Zhi-Jun; Li Pan-Lai; Yang Zhi-Ping; Guo Qing-Lin

    2013-01-01

    A series of SrIn2O4:Eu3+ phosphors are synthesized by a high temperature solid-state method,and their luminescent properties are investigated.They can be excited by 395-nm radiation,and produce red emission (619 nm); however,they have a low absorption of near-ultraviolet light with the wavelength of 400 nm-405 nm.When co-doped with A+ (A =Li,Na,K),the emission intensity of SrIn2O4:Eu3+ is significantly enhanced,but its emission and excitation spectral profile is unchanged.With co-doping Sm3+,not only is the emission intensity of SrIn2O4:Eu3+ enhanced,but also the absorption is broadened and strengthened in the range of 400 nm-405 nm.The effect of Sm3+-doped content on the emission intensity of SrIn2O4:Eu3+,Sm3+ is investigated,and the optimal Sm3+ content is 0.02 mol.

  20. Calculating models of mass action concentrations for NaBr(aq), LiNO3(aq),HNO3(aq), and KF(aq) binary solutions

    Institute of Scientific and Technical Information of China (English)

    Hanjie Guo; Weijie Zhao; Xuemin Yang

    2007-01-01

    The calculating models of mass action concentrations for electrolyte aqueous solutions NaBr-H2O, LiNO3-H2O, HNO3-H2O,and KF-H2O have been developed at 298.15 K and their molalities ranging from 0.1 mol/kg to saturation according to the ion and molecule coexistence theory as well as mass action law. The calculated mass action concentration is based on pure species as the standard state and the mole fraction as the concentration unit, and the reported activities are usually based on infinite dilution as the standard state and molality as the concentration unit. Hence, the calculated mass action concentration must be transformed to the same standard state and concentration unit. The transformation coefficients between calculated mass action concentrations and reported activities of the same component fluctuate in a very narrow range. Thus, the transformed mass action concentrations not only agree well with reported activities, but also strictly obey mass action law. The calculated results show that the new developed models can embody the intrinsic structure of investigated four electrolyte aqueous solutions. The results also indicate that mass action law has its widespread applicability to electrolyte binary aqueous solutions.

  1. Investigations on vanadyl doped ARbB4O7 (A=Li, Na, K) glasses by EPR and optical studies

    International Nuclear Information System (INIS)

    EPR and optical absorption investigations are carried out at room temperature on vanadyl doped ARbB4O7 (A=Li, Na, K) glasses. These results indicate that the VO2+ ion enters the glass matrix into a tetragonally compressed octahedral site. The spin-Hamiltonian parameters calculated from the EPR spectra for the three glass systems LRB, NRB and KRB are: gparallel=1.948, gorthogonal=1.976, Aparallel=157x10-4, Aorthogonal=58x10-4cm-1; gparallel=1.948, gorthogonal=1.977, Aparallel=157x10-4, Aorthogonal58x10-4cm-1 and gparallel=1.948, gorthogonal=1.979, Aparallel=157x10-4, Aorthogonal59x10-4cm-1, respectively. The optical spectrum exhibits three characteristic bands for all these glasses suggesting C4v symmetry. The crystal field and tetragonal field parameters evaluated using the optical data for the three systems LRB, NRB and KRB are: Dq=1666, Ds=-3339, Dt=450cm-1; Dq=1666, Ds=-3329, Dt=441cm-1 and Dq=1666, Ds=-3219 and Dt=507cm-1, respectively. The bonding parameters indicate a moderately covalent bond between the metal ions and ligands

  2. Remote Control Effect of Li+, Na+, K+ Ions on the Super Energy Transfer Process in ZnMoO4:Eu3+, Bi3+ Phosphors

    Science.gov (United States)

    Ran, Weiguang; Wang, Lili; Tan, Lingling; Qu, Dan; Shi, Jinsheng

    2016-06-01

    Luminescent properties are affected by lattice environment of luminescence centers. The lattice environment of emission centers can be effectively changed due to the diversity of lattice environment in multiple site structure. But how precisely control the doped ions enter into different sites is still very difficult. Here we proposed an example to demonstrate how to control the doped ions into the target site for the first time. Alkali metal ions doped ZnMoO4:Bi3+, Eu3+ phosphors were prepared by the conventional high temperature solid state reaction method. The influence of alkali metal ions as charge compensators and remote control devices were respectively observed. Li+ and K+ ions occupy the Zn(2) sites, which impede Eu and Bi enter the adjacent Zn(2) sites. However, Na+ ions lie in Zn(1) sites, which greatly promoted the Bi and Eu into the adjacent Zn(2) sites. The Bi3+ and Eu3+ ions which lie in the immediate vicinity Zn(2) sites set off intense exchange interaction due to their short relative distance. This mechanism provides a mode how to use remote control device to enhance the energy transfer efficiency which expected to be used to design efficient luminescent materials.

  3. Influence of the A/B nonstoichiometry, composition modifiers, and preparation methods on properties of Li- and Ta-modified (K,Na)NbO3 ceramics

    Science.gov (United States)

    Morozov, Maxim I.; Hoffmann, Michael J.; Benkert, Katrin; Schuh, Carsten

    2012-12-01

    Properties of Li- and Ta- modified (K,Na)NbO3 piezoceramics with the base composition near the orthorhombic-tetragonal phase boundary have been investigated with respect to variation of temperature, stoichiometry, compositional homogeneity, atmosphere of thermal treatment, and dopants (Ba, Mn). Although the influence of the most of the abovementioned factors has already been reported in the literature, the paper focuses on several aspects of the composition—property relationships that still remain controversial or poorly elucidated. In particular, we show that improvement of compositional homogeniety in these ceramics emphasizes the instability of piezoelectric response with respect to variation of temperature in the vicinity of the orthorhombic-tetragonal phase transition. Ba dopant is shown to suppress conductivity in ceramics sintered in air, though it makes conductivity more sensitive to variation of the oxygen partial pressure. Mn dopant is shown to suppress conductivity and strongly reduce the influence of the oxygen partial pressure on conductivity of the ceramics. Finally, we show that chemical modifications to the ceramic composition, such as Mn dopant or variation of nonstoichiometry affect the piezoelectric response mainly by the shift of the orthorhombic-tetragonal phase transition temperature.

  4. Remote Control Effect of Li(+), Na(+), K(+) Ions on the Super Energy Transfer Process in ZnMoO4:Eu(3+), Bi(3+) Phosphors.

    Science.gov (United States)

    Ran, Weiguang; Wang, Lili; Tan, Lingling; Qu, Dan; Shi, Jinsheng

    2016-01-01

    Luminescent properties are affected by lattice environment of luminescence centers. The lattice environment of emission centers can be effectively changed due to the diversity of lattice environment in multiple site structure. But how precisely control the doped ions enter into different sites is still very difficult. Here we proposed an example to demonstrate how to control the doped ions into the target site for the first time. Alkali metal ions doped ZnMoO4:Bi(3+), Eu(3+) phosphors were prepared by the conventional high temperature solid state reaction method. The influence of alkali metal ions as charge compensators and remote control devices were respectively observed. Li(+) and K(+) ions occupy the Zn(2) sites, which impede Eu and Bi enter the adjacent Zn(2) sites. However, Na(+) ions lie in Zn(1) sites, which greatly promoted the Bi and Eu into the adjacent Zn(2) sites. The Bi(3+) and Eu(3+) ions which lie in the immediate vicinity Zn(2) sites set off intense exchange interaction due to their short relative distance. This mechanism provides a mode how to use remote control device to enhance the energy transfer efficiency which expected to be used to design efficient luminescent materials. PMID:27278286

  5. Remote Control Effect of Li+, Na+, K+ Ions on the Super Energy Transfer Process in ZnMoO4:Eu3+, Bi3+ Phosphors

    Science.gov (United States)

    Ran, Weiguang; Wang, Lili; Tan, Lingling; Qu, Dan; Shi, Jinsheng

    2016-01-01

    Luminescent properties are affected by lattice environment of luminescence centers. The lattice environment of emission centers can be effectively changed due to the diversity of lattice environment in multiple site structure. But how precisely control the doped ions enter into different sites is still very difficult. Here we proposed an example to demonstrate how to control the doped ions into the target site for the first time. Alkali metal ions doped ZnMoO4:Bi3+, Eu3+ phosphors were prepared by the conventional high temperature solid state reaction method. The influence of alkali metal ions as charge compensators and remote control devices were respectively observed. Li+ and K+ ions occupy the Zn(2) sites, which impede Eu and Bi enter the adjacent Zn(2) sites. However, Na+ ions lie in Zn(1) sites, which greatly promoted the Bi and Eu into the adjacent Zn(2) sites. The Bi3+ and Eu3+ ions which lie in the immediate vicinity Zn(2) sites set off intense exchange interaction due to their short relative distance. This mechanism provides a mode how to use remote control device to enhance the energy transfer efficiency which expected to be used to design efficient luminescent materials. PMID:27278286

  6. Influence of current density on the erosion of a graphite cathode and electrolytic formation of carbon nanotubes in molten NaCl and LiCl

    International Nuclear Information System (INIS)

    The electrochemical deposition of sodium and lithium from their respective molten chlorides onto a graphite cathode as the first step of carbon nanotube electrolytic production has been investigated. It has been shown that in the case of both sodium and lithium, as the cathodic current density increases, the cathode weight first increases and then decreases, i.e. the dependence of cathode weight change vs. cathodic current density passes through a maximum. The value of cathodic current density corresponding to the maximum increase in the cathode weight in the case of sodium is approximately 4 times as high as that in the case of lithium, which is explained by a higher solubility of sodium metal in molten sodium chloride compared to that of lithium metal in molten lithium chloride. The higher sodium metal solubility causes a higher electronic conductivity of the molten electrolyte, while the ratio of intercalated to dissolved sodium will be lower as compared to lithium. Curved multi-walled carbon nanotubes of an outer diameter of 20-50 nm with a wall thickness of 5-10 nm (molten NaCl) and of 20-100 nm with a wall thickness of 5-40 nm (molten LiCl) have been synthesized.

  7. Rules on intrapair and interpair correlation energy for Cl,Cl~- and MCl(M=H,Li,Na,K)

    Institute of Scientific and Technical Information of China (English)

    韦吉崇; 禚淑苹; 居冠之

    2001-01-01

    According to the calculation results of the intrapair and interpair correlation energy for the title systems, it has been found that the intrapair correlation energy of K shell of Cl is almost a constant and both the intrashell and intershell correlation energy of K and L shell changes little. It has also been found that in MCI series compounds the value of Cl correlation energy contribution depends on the ionicity of MCI compounds, i.e., the Cl correlation energy contribution increases with the increase of the ionic bond strength of the compound and this value is always less than the correlation energy of Cl" anion but always larger than that of Cl atom. These rules are helpful for the estimation of the correlation energy of ionic compounds and the energy changes of chemical reactions.

  8. Rules on intrapair and interpair correlation energy for Cl, Cl- and MCl (M=H, Li, Na, K)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    According to the calculation results of the intrapair and interpair correlation energy for the title systems, it has been found that the intrapair correlation energy of K shell of Cl is almost a constant and both the intrashell and intershell correlation energy of K and L shell changes little. It has also been found that in MCl series compounds the value of Cl correlation energy contribution depends on the ionicity of MCl compounds, i.e., the Cl correlation energy contribution increases with the increase of the ionic bond strength of the compound and this value is always less than the correlation energy of Cl- anion but always larger than that of Cl atom. These rules are helpful for the estimation of the correlation energy of ionic compounds and the energy changes of chemical reactions.

  9. State of difficultly soluble uranosilicates of MIHSiUO6·nH2O composition in saturated aqueous solutions (M+=Li+, Na+, K+, Rb+, Cs+, NH4+)

    International Nuclear Information System (INIS)

    Solubility of uranosilicates of MIHSiUO6·nH2O (M+=Li+, Na+, K+, Rb+, Cs+, NH4+) series is investigated experimentally in aqueous solutions at 25 Deg C. Equilibrium constants of dissolution reactions of uranosilicates in acid and neutral media are calculated using data obtained, composition of equilibrium solutions is investigated, standard Gibbs' formation functions are calculated using data on solubility. Forecasting of behaviour in different conditions of compounds investigated is presented

  10. Evaluation of nanocrystalline Sn3N4 derived from ammonolysis of Sn(NEt2)4as a negative electrode material for Li-ion and Na-ion batteries

    OpenAIRE

    Li, Xianji; Hector, Andrew L.; John R. Owen; Shah, S. Imran U.

    2016-01-01

    Bulk nanocrystalline Sn3N4 powders were synthesised by a two step ammonolysis process followed by washing with dilute acid. Their performance as Li-ion and Na-ion battery negative electrodes was assessed by galvanostatic cycling in half cells vs. the metal, giving good performance in both cases and remarkable stability in the sodium cells. The effect of carboxymethyl cellulose and sodium alginate binders was examined and the latter found to give superior performance. Capacity and stability we...

  11. Effect of MnO doping on the structure, microstructure and electrical properties of the (K,Na,Li)(Nb,Ta,Sb)O{sub 3} lead-free piezoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rubio-Marcos, F., E-mail: fernando.rubio-marcos@unilim.fr [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Marchet, P. [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Vendrell, X. [Grup de Quimica de l' Estat Solid, Departament de Quimica Inorganica, Universitat de Barcelona, 08028 Barcelona (Spain); Romero, J.J. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Remondiere, F. [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Mestres, L. [Grup de Quimica de l' Estat Solid, Departament de Quimica Inorganica, Universitat de Barcelona, 08028 Barcelona (Spain); Fernandez, J.F. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain)

    2011-09-01

    Highlights: {center_dot} MnO doping effects on structure and properties of (K,Na,Li)(Nb,Ta,Sb)O{sub 3} piezoceramics. {center_dot} The structure changes towards an orthorhombic symmetry for higher MnO concentrations. {center_dot} High doping levels induce a tetragonal tungsten-bronze secondary phase. {center_dot} Mn{sup 2+} doping modifies the phase transition temperature and the piezoelectric properties. {center_dot} Manganese doping increases the mechanical quality factor Q{sub m}. - Abstract: Mn{sup 2+}-doped (K,Na,Li)(Nb,Ta,Sb)O{sub 3} lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn{sup 2+} doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O{sub 3} structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn{sup 2+} ions incorporate into the perovskite structure in different off ways depending on their concentration.

  12. Domain formation and polarization reversal under atomic force microscopy-tip voltages in ion-sliced LiNbO{sub 3} films on SiO{sub 2}/LiNbO{sub 3} substrates

    Energy Technology Data Exchange (ETDEWEB)

    Gainutdinov, R. V.; Volk, T. R. [Shubnikov Institute of Crystallography RAS, 119333 Moscow (Russian Federation); Zhang, H. H. [Jinan Jingzheng Electronics Co., Ltd., 250101 Jinan (China)

    2015-10-19

    We report on studies on writing of micro- and nanodomains and specified domain patterns by AFM-tip voltages U{sub DC} in thin (0.5 μm thick) ion-sliced LiNbO{sub 3} films embedded to SiO{sub 2}/LiNbO{sub 3} substrates. A peculiar feature is an overlapping of domains as the distance between them decreases. Piezoelectric hysteresis loops were measured in a wide range of U{sub DC} pulse durations. Domain dynamics and characteristics of hysteresis loops reveal marked distinctions from those observed so far in LiNbO{sub 3} films and bulk crystals.

  13. Thermal conductivity and dielectric functions of alkali chloride XCl (X = Li, Na, K and Rb): a first-principles study

    Science.gov (United States)

    Xu, M.; Yang, J. Y.; Liu, L. H.

    2016-07-01

    The macroscopic physical properties of solids are fundamentally determined by the interactions among microscopic electrons, phonons and photons. In this work, the thermal conductivity and infrared–visible–ultraviolet dielectric functions of alkali chlorides and their temperature dependence are fully investigated at the atomic level, seeking to unveil the microscopic quantum interactions beneath the macroscopic properties. The microscopic phonon–phonon interaction dominates the thermal conductivity which can be investigated by the anharmonic lattice dynamics in combination with Peierls–Boltzmann transport equation. The photon–phonon and electron–photon interaction intrinsically induce the infrared and visible–ultraviolet dielectric functions, respectively, and such microscopic processes can be simulated by first-principles molecular dynamics without empirical parameters. The temperature influence on dielectric functions can be effectively included by choosing the thermally equilibrated configurations as the basic input to calculate the total dipole moment and electronic band structure. The overall agreement between first-principles simulations and literature experiments enables us to interpret the macroscopic thermal conductivity and dielectric functions of solids in a comprehensive way.

  14. Cathodic behaviour and oxoacidity reactions of samarium (III) in two molten chlorides with different acidity properties: The eutectic LiCl–KCl and the equimolar CaCl2–NaCl melt

    International Nuclear Information System (INIS)

    Highlights: ► The E1/2rev, k0, and α, of the Sm(III)/Sm(II) system have been calculated for the first time. ► DSm(III) has been calculated avoiding the meniscus effect. Sm(III) diffuses slower in CaCl2–NaCl than in LiCl–KCl. ► Sm(III) is more solvated in LiCl–KCl than in CaCl2–NaCl. ► The solubility of SmOCl is higher in the equimolar CaCl2–NaCl than in the eutectic LiCl–KCl. ► Sm2O3 is a stronger oxobase in CaCl2–NaCl than in LiCl–KCl, leading in both melts to the formation of SmOCl. -- Abstract: This work presents a study on the chemical and electrochemical properties of Sm(III) solutions in two molten chloride mixtures with different acidity properties: (i) the eutectic LiCl–KCl, in the temperature range 673–823 K and (ii) the equimolar CaCl2–NaCl melt at 823 K. In both media and on a W inert electrode, the electro-reduction of Sm(III) takes place via one step Sm(III)/Sm(II). The second system Sm(II)/Sm(0) has not been observed within the electrochemical windows, because of the prior reduction of Li(I) and Na(I) from the solvent, which inhibits the electro-extraction of Sm species from the salts on the inert substrate. On the W electrode, the electro-reduction of Sm(III) to Sm(II) takes place in a quasi-reversible electrochemical mode. Accurate values of the reversible half wave potential, the intrinsic rate constant of charge transfer, k0, and the charge transfer coefficient, α, have been calculated for the first time in both molten chlorides, by simulation of the cyclic voltammograms and logarithmic analysis of the convoluted curves. The diffusion coefficient of Sm(III) has been also calculated by different electrochemical techniques, avoiding the meniscus effect by modification of the immersion dept of the working electrode in stages. The values of the diffusion coefficient indicate that Sm(III) diffuses slower in the equimolar CaCl2–NaCl than in the eutectic LiCl–KCl. This behaviour can be explained by the different

  15. LiB 3O 5 crystal structure at 20, 227 and 377 °C

    Science.gov (United States)

    Shepelev, Yu. F.; Bubnova, R. S.; Filatov, S. K.; Sennova, N. A.; Pilneva, N. A.

    2005-10-01

    Crystal structure of LiB 3O 5 (a framework of [B 3O 5] - rings and Li atoms located in interspaces) was refined at high temperatures using single-crystal X-ray diffraction, Mo Kα-radiation, anharmonic approximation, orthorhombic; Pna2 1; Z=4; 20 °C ( a=8.444, b=7.378, c=5.146 Å, 1411 F( hkl), R=0.022); 227 °C ( a=8.616, b=7.433, c=5.063 Å, 1336 F( hkl), R=0.026), 377 °C ( a=8.746, b=7.480, c=5.013 Å, 1193 F( hkl), R=0.035). A high mobility of Li atoms and their highly asymmetric vibrations are revealed. Ellipsoid of Li thermal vibrations is oviform. Li is shifted on heating to 0.26 Å mainly along a-axis causing high thermal expansion in this direction; Li temperature factors are multiplied by 4 on heating. Rigid boron-oxygen groups in LiB 3O 5 remain practically stable on heating similar to α-Na 2B 8O 13 and α-CsB 5O 8. At the same time these groups rotate relative to each other like hinges leading to extremely anisotropic thermal expansion ( α a=101, α b=31, α c=-71, α v=60×10 -6 °C -1, 20-530 °C, HTXRPD data).

  16. Electron impact ionization and excitation of laser-excited atoms: investigation by means of electron spectrometry

    International Nuclear Information System (INIS)

    We have measured the electron spectra following the excitation and ionization of laser-excited atoms by impact of 1.5 keV electrons: 2p excitation and 2s ionization of Na(3p3/2), 1s excitation of Li(2p3/2) and 5p ionization of Ba(6s5d 1,3D). Except for Ba the intensities of ejected electrons are directly proportional to the cross sections of Auger and autoionizing states. Theoretical excitation cross sections (Na 2p, Li 1s) are obtained in first Born approximation including the full relaxation of the atomic electrons. Relative ionization cross sections (Na 2s, Ba 5p) are evaluated in sudden approximation as a two-step process: pure 2s(5p) ionization plus relaxation of the rest of the atomic electrons. The experimental spectra are compared to theoretical spectra

  17. Prediction of Setschenow constants of N-heteroaromatics in NaCl solutions based on the partial charge on the heterocyclic nitrogen atom.

    Science.gov (United States)

    Yang, Bin; Li, Zhongjian; Lei, Lecheng; Sun, Feifei; Zhu, Jingke

    2016-02-01

    The solubilities of 19 different kinds of N-heteroaromatic compounds in aqueous solutions with different concentrations of NaCl were determined at 298.15 K with a UV-vis spectrophotometry and titration method, respectively. Setschenow constants, Ks, were employed to describe the solubility behavior, and it is found that the higher ring numbers of N-heteroaromatics gave rise to the lower values of Ks. Moreover, Ks showed a good linear relationship with the partial charge on the nitrogen atom (QN) for either QN > 0 or QN NaCl solution for QN 0. PMID:26490915

  18. Oscillation Frequencies for Simultaneous Trapping of Heteronuclear Alkali Atoms

    CERN Document Server

    Kaur, Kiranpreet; Arora, Bindiya

    2016-01-01

    We investigate oscillation frequencies for simultaneous trapping of more than one type of alkali atoms in a common optical lattice. For this purpose, we present numerical results for magic trapping conditions, where the oscillation frequencies for two different kind of alkali atoms using laser lights in the wavelength range 500-1200 nm are same. These wavelengths will be of immense interest for studying static and dynamic properties of boson-boson, boson-fermion, fermion-fermion, and boson-boson-boson mixtures involving different isotopes of Li, Na, K, Rb, Cs and Fr alkali atoms. In addition to this, we were also able to locate a magic wavelength around 808.1 nm where all the three Li, K, and Rb atoms are found to be suitable for oscillating at the same frequency in a common optical trap.

  19. Formation and Characterization of Li0.24+2xLa0.59-xMxTiO3-LaPO4 (M=K, Na) System

    Institute of Scientific and Technical Information of China (English)

    Liu Huiyong; Wang Wenji

    2005-01-01

    Li0.24+2xLa0.59-xMxTiO3-LaPO4 (M=K, Na) fast ionic conductor was synthesized by high temperature solid state reaction. A.C. Impedance measurements show that the compositions of system have better conductivities in low doping content of Na+ and K+, as the doping content increases, the conductivity goes down in Na+ doping system. But in doping K+ system, the conductivity goes down and then goes up with the increasing content of K+. The activation energies of different doped ions are about 20 kJ·mol-1 in the temperature range of 25~400 ℃. X-ray powder diffraction shows that the doped Na+ and K+ would not affect the structure of compositions in the system. The main phase is Li0.24+2xLa0.59-xMxTiO3 perovskite solid solution, LaPO4 as a second phase also can be found. With increasing the content of M (x>0.04), unknown phase appears. IR measurement also indicates that the structure of compositions in the system would not be affected by doping alkali ion.

  20. Mixed alkali effect in Li2O-Na2O-B2O3 glasses containing Fe2O3-An EPR and optical absorption study

    International Nuclear Information System (INIS)

    This paper reports the interesting results on mixed alkali effect (MAE) in xLi2O-(30-x)Na2O-69.5B2O3 (5 ≤ x ≤ 28) glasses containing Fe2O3 studied by electron paramagnetic resonance (EPR) and optical absorption techniques. The EPR spectra in these glasses exhibit three resonance signals at g = 7.60, 4.20 and 2.02. The resonance signal at g = 7.60 has been attributed to Fe3+ ions in axial symmetry sites whereas the resonance signal at g = 4.20 is due to isolated Fe3+ ions in rhombic symmetry site. The resonance signal at g = 2.02 is due to Fe3+ ions coupled by exchange interaction. It is interesting to observe that the number of spins participating in resonance (N) and its paramagnetic susceptibility (χ) exhibits the mixed alkali effect with composition. The present study also gives an indication that the size of alkali ions we choose in mixed alkali glasses is also an important contributing factor in showing the mixed alkali effect. It is observed that the variation of N with temperature obeys Boltzmann law. A linear relationship is observed between 1/χ and T in accordance with Curie-Weiss law. The paramagnetic Curie temperature (θ p) is negative for the investigated sample, which suggests that the iron ions are antiferromagnetically coupled by negative super exchange interactions at very low temperatures. The optical absorption spectra exhibit only one weak band corresponding to the transition 6A1g(S) →4A1g(G); 4Eg(G) at 446 nm which is a characteristic of Fe3+ ions in octahedral symmetry

  1. Investigations on vanadyl doped ARbB{sub 4}O{sub 7} (A=Li, Na, K) glasses by EPR and optical studies

    Energy Technology Data Exchange (ETDEWEB)

    Ravikumar, R.V.S.S.N. [Department of Chemistry, Pondicherry University, Pondicherry 605 014 (India)]. E-mail: rvssn@yahoo.co.in; Chandrasekhar, A.V. [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Reddy, Y.P. [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Department of Physics, Sri Padmavathy Mahila Viswa Vidyalayam (Women' s University), Tirupati 517 502 (India); Komatsu, R. [Department of Advanced Materials Science and Engineering, Yamaguchi University, Tokiwadai, Ube 755-8611 (Japan); Ikeda, K. [Department of Advanced Materials Science and Engineering, Yamaguchi University, Tokiwadai, Ube 755-8611 (Japan); Yamauchi, J. [Department of Chemistry, Kyoto University, Sakyo-Ku, Kyoto 606-8501 (Japan); Sambasiva Rao, P. [Department of Chemistry, Pondicherry University, Pondicherry 605 014 (India)

    2007-05-15

    EPR and optical absorption investigations are carried out at room temperature on vanadyl doped ARbB{sub 4}O{sub 7} (A=Li, Na, K) glasses. These results indicate that the VO{sup 2+} ion enters the glass matrix into a tetragonally compressed octahedral site. The spin-Hamiltonian parameters calculated from the EPR spectra for the three glass systems LRB, NRB and KRB are: g{sub parallel}=1.948, g{sub orthogonal}=1.976, A{sub parallel}=157x10{sup -4}, A{sub orthogonal}=58x10{sup -4}cm{sup -1}; g{sub parallel}=1.948, g{sub orthogonal}=1.977, A{sub parallel}=157x10{sup -4}, A{sub orthogonal}58x10{sup -4}cm{sup -1} and g{sub parallel}=1.948, g{sub orthogonal}=1.979, A{sub parallel}=157x10{sup -4}, A{sub orthogonal}59x10{sup -4}cm{sup -1}, respectively. The optical spectrum exhibits three characteristic bands for all these glasses suggesting C{sub 4v} symmetry. The crystal field and tetragonal field parameters evaluated using the optical data for the three systems LRB, NRB and KRB are: Dq=1666, Ds=-3339, Dt=450cm{sup -1}; Dq=1666, Ds=-3329, Dt=441cm{sup -1} and Dq=1666, Ds=-3219 and Dt=507cm{sup -1}, respectively. The bonding parameters indicate a moderately covalent bond between the metal ions and ligands.

  2. Enhanced high-rate electrochemical performance of Li3V1.8Mn0.2(PO4)3 by atomic doping of Mn(III)

    International Nuclear Information System (INIS)

    Mn(III) doped Li3V2-xMnx(PO4)3/C (x = 0.2) is prepared by sol-gel method. Mn(III) is well substituted the position of V in Li3V2(PO4)3 (LVP) without any Mn-contained impurity phase. The crystal structure and morphology in Mn-substituted Li3V2(PO4)3 are studied by X-ray diffraction patterns (XRD), XPS and scanning and high-resolution transmission electronic microscopy (SEM and HRTEM). Mn(III) substitution increases the electrochemical performance of Li3V2(PO4)3 at high cut-off voltage of 4.8 V. Li3V1.8Mn(III)0.2(PO4)3 delivers 185 mAh g−1 at 0.1 C, close to the theoretical capacity of Li3V2(PO4)3, and delivers initial capacities of 130 and 126 mAh g−1 at 5 C and 10 C-rate, remaining 95% and 97% of the initial capacities after 100 cycles when charged to 4.8 V. Mn(III) plays an important role in maintaining the three-dimensional (3D) solid framework structure to provide an improved cycle life at higher cut-off voltage of 4.8 V and improving the high-rate performance of Li3V2(PO4)3

  3. Na{sub 2}EDTA-assisted hydrothermal synthesis and electrochemical performance of LiFePO{sub 4} powders with rod-like and block-like morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Juan, E-mail: juanwang168@gmail.com [Shaanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi' an University of Architecture and Technology, Xi' an 710055 (China); Zheng, Siqi; Yan, Hao; Zhang, Haipeng [Shaanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi' an University of Architecture and Technology, Xi' an 710055 (China); Hojamberdiev, Mirabbos [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama, Kanagawa 226-8503 (Japan); Ren, Bing; Xu, Yunhua [Shaanxi Key Laboratory of Nanomaterials and Nanotechnology, Xi' an University of Architecture and Technology, Xi' an 710055 (China)

    2015-06-15

    Nano and micro-sized LiFePO{sub 4} were synthesized by disodium ethylenediamine tetraacetate (Na{sub 2}EDTA) – assisted hydrothermal synthesis method with the pH of synthesizing solution in the range from 2 to 8. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and electrochemical performance experiments. The obtained results showed that the pH of synthesizing solution played a key role in the formation of the final products with different morphologies, including rod-like and block-like structures and so on. The formation mechanism and the influence of Na{sub 2}EDTA on the morphology of LiFePO{sub 4} micro- and nanocrystals were investigated as a function of pH value. The results of electrochemical performance measurement revealed that the charge/discharge cycling characteristics of the samples were varied by tailoring their morphologies. Particularly, the block-like LiFePO{sub 4} particles with the average size of 200–600 nm present the highest initial discharge capacity of 141 mAh/g at 0.1C rate, and cycling stability of this sample is optimal among all the obtained products owing to its good diffusion properties. It also exhibits an excellent rate capability with high discharge capacities of more than 93.2 mAh/g at 5C after 80 cycles. The present study offers a simple way to synthesize and design high performance cathode materials for lithium-ion batteries by the methods of morphology control without carbon coating or doping with supervalent cations. - Highlights: • Nano and micro-sized LiFePO{sub 4} were synthesized by a hydrothermal synthesis method. • Effect of the pH of synthesizing solution on the formation of LiFePO{sub 4} was studied. • The block-like LiFePO{sub 4} particles present the highest initial discharge capacity. • The rate capability of the block-like LiFePO{sub 4} is more than 93.2 m

  4. Anion Coordination Interactions in Solvates with the Lithium Salts LiDCTA and LiTDI

    Energy Technology Data Exchange (ETDEWEB)

    McOwen, Dennis W.; Delp, Samuel A.; Paillard, Elie; Herriot, Cristelle; Han, Sang D.; Boyle, Paul D.; Sommer, Roger D.; Henderson, Wesley A.

    2014-04-17

    Lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) and lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI) are two salts proposed for lithium battery electrolyte applications, but little is known about the manner in which the DCTA- and TDI- anions coordinate Li+ cations. To explore this in-depth, crystal structures are reported here for two solvates with LiDCTA: (G2)1:LiDCTA and (G1)1:LiDCTA with diglyme and monoglyme, respectively, and seven solvates with LiTDI: (G1)2:LiTDI, (G2)2:LiTDI, (G3)1:LiTDI, (THF)1:LiTDI, (EC)1:LiTDI, (PC)1:LiTDI and (DMC)1/2:LiTDI with monoglyme, diglyme, triglyme, tetrahydrofuran, ethylene carbonate, propylene carbonate and dimethyl carbonate, respectively. These latter solvate structures are compared with the previously reported acetonitrile (AN)2:LiTDI structure. The solvates indicate that the LiTDI salt is much less associated than the LiDCTA salt and that the ions in LiTDI, when aggregated in solvates, have a very similar TDI-...Li+ cation mode of coordination through both the anion ring and cyano nitrogen atoms. Such coordination facilitates the formation of polymeric ion aggregates, instead of dimers. Insight into such ion speciation is instrumental for understanding the electrolyte properties of aprotic solvent mixtures with these salts.

  5. Neutron diffraction study of the atomic structure of cubic sodium-tungsten bronze (Na{sub 0.69}WO{sub 3}) single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Isakov, I. V., E-mail: ngkolin48@mail.ru; Kalyukanov, A. I. [Karpov Institute of Physical Chemistry (Obninsk Branch) (Russian Federation); Volkov, V. L. [Institute of Solid-State Chemistry (Russian Federation); Ozerov, R. P.; Fykin, L. E. [Karpov Institute of Physical Chemistry (Obninsk Branch) (Russian Federation)

    2011-05-15

    The atomic structure of a single crystal of one of four Na{sub 0.69}WO{sub 3} phases, which exist below 293 K, has been refined from neutron diffraction data (WWR-c reactor at the Karpov Institute of Physical Chemistry, Obninsk Branch; {lambda} = 1.168 Angstrom-Sign ; {lambda}/2 contribution < 0.8%; sin{theta}/{lambda} {<=} 0.810; T = 288 K; crystal sphere Empty-Set = 4.4 mm; cubic unit cell with a = 7.672 Angstrom-Sign , sp. gr. Im3, z = 8, {mu} = 1.9 mm{sup -1}). The Na{sub 0.69}WO{sub 3} atomic structure has been refined (198 independent reflections) taking into account the anisotropy of thermal vibrations (R{sub w} = 4.0%). The stoichiometric coefficient Na(0.69) is also refined. A structural distortion is revealed, which is characterized by the displacement of oxygen atoms (0, 0.2609(2), 0.2391(2)) from the ideal perovskite positions (0, 1/4, 1/4); this displacement doubles the ideal perovskite lattice period. The oxygen displacements can be described as rotations of oxygen octahedra by 3.58 Degree-Sign around the [111] direction. The structure remains cubic because the octahedra rotations with respect to all three perovskite cubic axes are identical.

  6. Neutron diffraction study of the atomic structure of cubic sodium-tungsten bronze (Na0.69WO3) single crystal

    International Nuclear Information System (INIS)

    The atomic structure of a single crystal of one of four Na0.69WO3 phases, which exist below 293 K, has been refined from neutron diffraction data (WWR-c reactor at the Karpov Institute of Physical Chemistry, Obninsk Branch; λ = 1.168 Å; λ/2 contribution −1). The Na0.69WO3 atomic structure has been refined (198 independent reflections) taking into account the anisotropy of thermal vibrations (Rw = 4.0%). The stoichiometric coefficient Na(0.69) is also refined. A structural distortion is revealed, which is characterized by the displacement of oxygen atoms (0, 0.2609(2), 0.2391(2)) from the ideal perovskite positions (0, 1/4, 1/4); this displacement doubles the ideal perovskite lattice period. The oxygen displacements can be described as rotations of oxygen octahedra by 3.58° around the [111] direction. The structure remains cubic because the octahedra rotations with respect to all three perovskite cubic axes are identical.

  7. Phase Transition and High Piezoactivity of Sb Doped (Na0.53K0.435Li0.035)Nb0.94Ta0.06O3 Lead-Free Ceramics

    Institute of Scientific and Technical Information of China (English)

    QI Peng; WANG Jin-Feng; MING Bao-Qua; WANG Chun-Ming; LIANG Xing-Hua

    2007-01-01

    Lead-free piezoelectric ceramics with the composition of (Nao0.53K0.435Li0.035)Nb0.94-xSbxTa0.06O3(NKLNST)are synthesized by a conventional solid-state sintering process.An MPB-like region between orthorhombic and pseudocubic phases is found in this system.The density,piezoelectric and dielectric properties are enhanced greatly in this region.A composition (Na0.53K0.435Li0.035)(Nb0.86Sb0.08Tao.06)O3 is found to have excellent electrical properties:d33=320pC/N,kp=49%and kt=43%,as well as relatively low loss,tan δ=4.2%,and high relative density higher than 96%.which indicare that this ceramics is a promising lead-free piezoceramicsreplacing for lead zirconate titanate.

  8. Structural characteristics of Mg-doped (1-x)(K0.5Na0.5)NbO3-xLiSbO3 lead-free ceramics as revealed by Raman spectroscopy

    International Nuclear Information System (INIS)

    This paper presents a Raman spectroscopic study of compositional-change-induced structure variation and of the related mechanism of Mg doping in LiSbO3 (LS)-modified (K0.5Na0.5)NbO3 (KNN) ceramics. With increasing LS content from 0 to 0.06, a discontinuous shift towards higher wavenumbers was found for the band position of the A1g(v1) stretching mode of KNN, accompanied by a clearly nonlinear broadening of this band and a decrease in its intensity. Such morphological changes in the Raman spectrum result from two factors: (i) changes in polarizability/binding strength of the O-Nb-O vibration upon incorporation of Li ions in the KNN perovskitic structure and (ii) a polymorphic phase transition (PPT) from orthorhombic to tetragonal (O → T) phase at x > 0.04. Upon increasing the amount, w, of Mg dopant incorporated into the (1-x)KNN-xLS ceramic structure, the intensity of the Raman bands are enhanced, while the peak position and the full width at half maximum of the A1g(v1) mode was found to experience a clear dependence on both w and x. Raman characterization revealed that the mechanism of Mg doping is strongly correlated with the concentration of Li in the perovskite structure: Mg2+ ions will preferentially replace Li+ ions for low Mg doping while replace K/Na ions for higher doping of Mg. The PPT O → T was also found to be altered by the introduction of Mg and the critical value of LS concentration, xO-T, for incipient O → T transition in the KNN-xLS-wMT system was strongly dependent on Mg content, with xO→T being roughly equal to 0.04 + 2w, for the case of dilute Mg alloying. (paper)

  9. Synthesis and Absorption Properties of New Na Specific Adsorbent Li1+xAlxTi2-x(PO4)3

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new kind of adsorbent Li1+xAlxTi2-x(PO4)3 was synthesized by solid state reaction method. The influence of the content of doping aluminum on the adsorbent Li1+xAlxTi2-x(PO4)3was investigated by XRD, while the morphology of powders was observed by SEM. The investigation of the adsorption properties showed that the adsorbent can selectively adsorb sodium with the adsorption capacity of 11.76 mg/g. The optimum conditions of adsorption are at pH 10.0-11.0 in LiCl solution.

  10. Implementing quantum electrodynamics with ultracold atomic systems

    CERN Document Server

    Kasper, V; Jendrzejewski, F; Oberthaler, M K; Berges, J

    2016-01-01

    We discuss the experimental engineering of model systems for the description of QED in one spatial dimension via a mixture of bosonic $^{23}$Na and fermionic $^6$Li atoms. The local gauge symmetry is realized in an optical superlattice, using heteronuclear boson-fermion spin-changing interactions which preserve the total spin in every local collision. We consider a large number of bosons residing in the coherent state of a Bose-Einstein condensate on each link between the fermion lattice sites, such that the behavior of lattice QED in the continuum limit can be recovered. The discussion about the range of possible experimental parameters builds, in particular, upon experiences with related setups of fermions interacting with coherent samples of bosonic atoms. We determine the atomic system's parameters required for the description of fundamental QED processes, such as Schwinger pair production and string breaking. This is achieved by benchmark calculations of the atomic system and of QED itself using function...

  11. Electric properties of textured (K$_{0.44}$Na$_{0.52}$Li$_{0.04}$)(Nb$_{0.86}Ta$_{0.10}$Sb$_{0.04}$)O$_3$ thick film prepared by screen printing method

    Indian Academy of Sciences (India)

    FANG FU; JIWEI ZHAI; ZHENGKUI XU

    2016-08-01

    Textured (K$_{0.44}$Na$_{0.52}$Li$_{0.04}$) (Nb$_{0.86}$Ta$_{0.10}$Sb$_{0.04}$)O$_3$ thick film was fabricated by the screen printing method with plate-like NaNbO3 particles as template. Thick film with 75% grain orientation was prepared. Remnant polarization and coercive field observed from the P–E loops of textured thick film were 3.6 $\\mu$C cm$^{−2}$ and 21 kV cm$^{−1}$, respectively. Textured (K$_{0.44}$Na$_{0.52}$Li$_{0.04}$) (Nb$_{0.86}$Ta$_{0.10}$Sb$_{0.04}$)O$_{3}$ thick film exhibited diffusion behaviour by analysing the temperature dependence of permittivity and loss tangent. The result of leakage current density showed a conduction mechanism of Schottky emission. Piezoelectric (PZT) properties of the thick film were characterized by the relationship of unipolar strain and applied electric field and the PZT constant $d^∗_{33}$ of textured thick film reached to 150 pm V$^{−1}$. Nonlinear PZT property of the thick film was investigated by Rayleigh law.

  12. Luminescence properties of a new red emitting Eu3+-doped alkaline-earth fluoborate phosphor: BaCa(1-2x)BO3F:xEu3+, xM+ (M=Li, Na, K)

    Institute of Scientific and Technical Information of China (English)

    SUN Jiayue; LAI Jinli; SUN Jianfeng; DU Haiyan

    2011-01-01

    A series of new red-emitting BaCa1-2xBO3F:xEu3+, xM+ (M=Li, Na, K) phosphors were synthesized by the solid-reaction method.X-ray diffraction (XRD), diffuse reflection (UV-vis) and photoluminescence spectra were utilized to characterize the crystallization process,structure and luminescence properties of the as-synthesized phosphors. The XRD results indicated that the sample began to crystallize at 800 ℃,and single-phase BaCaBO3F was fully obtained after annealing at 1000 C. The charge compensated behaviors were investigated in this paper by considering different cations like Li+, Na+ and K- acting as the charge compensator. The as-prepared phosphors had better emission properties, and the two characteristic emission lines peaking at 590 and 615 nm could be obtained upon 394, 463 and 532 nm excitation with the chromaticity coordinates of (0.596, 0.391), which were due to 5D0-7F1 and 5D0-TF2 transitions of Eu3+ ions. Further, the concentration quenching and corresponding luminescence mechanisms of BaCa1-2xBO3F:xEu3+, xNa+ phosphors were also discussed.

  13. First-principles calculation of the effects of Li-doping on the structure and piezoelectricity of (K0.5Na0.5)NbO3 lead-free ceramics.

    Science.gov (United States)

    Yang, D; Wei, L L; Chao, X L; Yang, Z P; Zhou, X Y

    2016-03-01

    The crystal structures of the lead-free piezoelectric ceramics (K0.5Na0.5)NbO3 and (K0.5Na0.5)0.94Li0.06NbO3 prepared by a solid-state method were investigated using first-principles calculations. The calculated values of piezoelectricity were in good agreement with the experimental data. We found that the primary contribution to piezoelectricity in this material comes from the hybridization of the O 2p and Nb 4d orbitals, which causes a change in the Nb-O bond length and the distortion of the Nb-O octahedral structure. Analysis of the band structure and the total density of states revealed that Li-doped (K0.5Na0.5)NbO3 enhances hybridization of the O 2p and Nb 4d orbitals. This hybridization enhancement further reduces the Nb-O1 bond length and enhances the distortion of the Nb-O octahedron along the [001] direction, which may be the main reason for the improvement of the piezoelectric properties. In addition, the piezoelectric coefficients are calculated here, which show the same trend as the experimental results. PMID:26906892

  14. A many-body model to study proteins. I. Applications to MLnm+ complexes, Mm+=Li+, Na+, K+, Mg2+, Ca2+, and Zn2+, L=H2O, CH3OH, HCONH2, n=1-6, and to small hydrogen bonded systems

    Science.gov (United States)

    Masella, Michel; Cuniasse, Philippe

    2003-07-01

    A new model to study proteinic systems including a many-body polarization and a hydrogen bond energy contribution is presented. This model represents an extension of an earlier water many-body model [M. Masella and J.-P. Flament, J. Chem. Phys. 107 9105 (1997)]. As in this earlier model, the new model is developed to reproduce quantum computations on small molecular aggregates, and, in this first paper, we focus our efforts in developing an accurate potential to describe interactions among all nonbonded atoms occurring in proteins, and among those atoms and six cations of biological interest: Li+, Na+, K+, Mg2+, Ca2+, and Zn2+. Intramolecular degrees of freedom are described as in classical two-body force fields. In the present paper, the new model is applied to investigate the properties of small ion-neutral [M,Ln]m+ complexes and of small hydrogen-bonded systems. The results showed that this model is able to reproduce most of the theoretical quantum predictions and experimental data published until now regarding those systems.

  15. Electrothermal atomic absorption spectrometric determination of lithium, sodium, potassium and copper in uranium without preliminary chemical separation

    International Nuclear Information System (INIS)

    Graphite furnace atomization is used for the direct determination of Li (0.25-4 ppm), Na (8-70 ppm), K (20-300 ppm) and Cu (0.5-25 ppm) in uranium dissolved in nitric acid, with relative standard deviations of 4-9%. Only iron seriously depresses the signals from the alkali metals. (Auth.)

  16. Electrochemical behavior of lanthanum and yttrium ions in two molten chlorides with different oxoacidic properties: The eutectic LiCl-KCl and the equimolar mixture CaCl2-NaCl

    Directory of Open Access Journals (Sweden)

    Castrillejo Y.

    2003-01-01

    Full Text Available The electrochemical behavior of LaCl3 and YCl3 was studied in two molten chloride mixtures with different oxoacidic properties, the eutectic LiCl-KCl and the equimolar CaCl2-NaCl melt at different temperatures. The stable oxidation states of both elements have been found to be (III and (0 in both melts, and it was found that both La(III and Y(III cations were less solvated by the chloride ions in the calcium-based melt, which was explained by the stability of CaCl4 2- ions in that melt. Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry and chronoamperometry were used in order to study the reaction mechanism and the transport parameters of electro active species at a tungsten electrode. The results showed that in the eutectic LiCl-KCl, the electro crystallization of lanthanum and yttrium seems to be the controlling electrochemical step while in CaCl2-NaCl this phenomenon has not been observed. That was explained in terms of the differences in the physicochemical properties of the systems, especially interfacial tensions. In the eutectic LiCl-KCl chronoamperometric studies indicated instantaneous and three dimensional nucleation and crystal growth of lanthanum and yttrium whatever the applied over potential of the rare earth metal is, whereas in the equimolar mixture CaCl2-NaCl, the corresponding electrochemical exchanges were found to be quasi-reversible, and the values of the kinetic parameters, K0 and α,were obtained for both reactions. Mass transport towards the electrode is a simple diffusion process, and the diffusion coefficients have been calculated. The validity of the Arrhenius law was also verified by plotting the variation of the logarithm of the diffusion coefficient versus 1/T.

  17. Enhancement of persistent luminescence of ZnTa{sub 2}O{sub 6}:Pr{sup 3+} by addition Li{sup +}, Na{sup +}, K{sup +} and Cs{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Noto, Luyanda L., E-mail: NotoLL@ufs.ac.za; Ntwaeaborwa, Orileng M.; Yagoub, Mubarak Y.A.; Swart, Hendrik C., E-mail: SwartHC@ufs.ac.za

    2015-10-15

    Graphical abstract: The incorporation of the alkali metals (Li, Na, K and Cs) as co-dopants in ZnTa{sub 2}O{sub 6}:Pr{sup 3+} phosphor improved the lifetime of the persistent emission by increasing the quantity of the electron trapping centres. - Highlights: • ZnTa{sub 2}O{sub 6}:Pr{sup 3+} was co-doped with Li{sup +}, Na{sup +}, K{sup +} or Cs{sup +} ions. • Phase pure samples were synthesised. • Enhancement of the persistent emission was achieved by co-doping. • Corresponding electron trapping centres were quantified by a TL reader. - Abstract: Enhancement of the persistent emission was achieved by co-doping ZnTa{sub 2}O{sub 6}:Pr{sup 3+} with Li{sup +}, Na{sup +}, K{sup +} or Cs{sup +} ions. Phase pure samples were synthesised and it was confirmed by the X-ray diffraction pattern which matches that of the standard data. Incorporation of the co-dopant ions introduced strain into the phosphor, which increased with an increase in the ionic radius of the co-dopant ion. The scanning electron microscope image shows that the particles were agglomerated, and the surface images obtained using the Time of flight secondary ion mass spectroscopy showed that the dopant and the co-dopant ions in the phosphor were homogeneously distributed. The persistent emission was enhanced by the co-dopant ions as shown by the lifetime values calculated from the phosphorescence decay curves, and the corresponding electron trapping centres were quantified by thermoluminescence reader.

  18. Experimental limits on the velocities of sodium atoms sputtered from solid surfaces by hydrogen ions. [Na cloud production around Io

    Science.gov (United States)

    Stoner, J. O., Jr.

    1976-01-01

    Optical emission at 589.0 nm by sodium atoms sputtered from solid targets by hydrogen molecular ions was observed, and no accompanying broadening or shifts of this line could be detected relative to that from a laboratory lamp. This allowed an upper limit of about 500,000 cm/sec on the mean speed of ejected sodium atoms to be calculated. The results are consistent with the hypothesis that the atomic sodium cloud surrounding Io is produced by this mechanism.

  19. Cyclic voltammetric study of the reduction of U(III) to uranium metal in molten LiCl-NaCl-CaCl2-BaCl2-UCl3

    International Nuclear Information System (INIS)

    Cyclic voltammetry was used to investigate the electrochemistry of the reduction of UCl3 to uranium metal in molten LiCl-NaCl-CaCl2-BaCl2 (49.7-8.0-26.5-15.8 mol %) containing dissolved UCl3. The purpose of the study was to obtain information on the kinetics of the reaction, which will be used in the design of electrorefining equipment for the reprocessing of core and blanket fuel discharged from the Integral Fast Reactor (IFR). The electrorefining operation employs the above salt as the electrolyte and a liquid cadmium pool as the anode

  20. Structure, microstructure and electrical properties of new lead-free (1-x)(Li0.12Na0.88)NbO3-xBaTiO3 (0 to x to 40) piezoelectric ceramics

    OpenAIRE

    Mitra, Supratim; Kulkarni, Ajit R

    2014-01-01

    A new lead-free (1-x)Li0.12Na0.88NbO3-xBaTiO3 (0 to x to 40) piezoelectric ceramics have been prepared using conventional ceramics processing route. Structural analysis revealed an existence of morphotropic phase boundary (MPB), separating orthorhombic and tetragonal phases, between the BaTiO3 content, x = 10-12.5. A partial phase diagram has been established based on temperature-dependent permittivity data for this new system and a nearly vertical temperature-independent MPB is observed. An ...

  1. The effect of sintering and poling processing on the phase structure of Li0.058(Na0.51K0.49)0.942NbO3 lead-free ceramics

    International Nuclear Information System (INIS)

    The phase structure of lead-free Li0.058(Na0.51K0.49)0.942NbO3 (KNNLN) ceramics can be affected by the stress as well as the external electric field. A high piezoelectric constant was obtained in KNNLN ceramics by adjusting the cooling-down speed of the sintering. The {2 0 0} reflection X-ray diffraction lines were measured to accurately identify the room-temperature crystal structure of the as-sintered samples. Dielectric measurements were performed to observe the differences in the phase structure of KNNLN ceramics before and after poling.

  2. Optical absorption and electron spin resonance studies of Cu2+ in Li2O–Na2O–B2O3–As2O3 glasses

    Indian Academy of Sciences (India)

    N Srinivasa Rao; Shashidhar Bale; M Purnima; K Siva Kumar; Syed Rahman

    2005-10-01

    The local structure around Cu2+ ion has been examined by means of electron spin resonance and optical absorption measurements in Li2O–(40 – )Na2O–50B2O3–10As2O3 glasses. The site symmetry around Cu2+ ions is tetragonally distorted octahedral. The ground state of Cu2+ is $d_{x^2–y^2}$. The glass exhibited broad absorption band near infrared region and small absorption band around 548 nm, which was assigned to the ${}^{2}B_{1g} \\rightarrow {}^{2}E_{g}$ transition.

  3. LiB3O5 crystal structure at 20, 227 and 377 deg. C

    International Nuclear Information System (INIS)

    Crystal structure of LiB3O5 (a framework of [B3O5]- rings and Li atoms located in interspaces) was refined at high temperatures using single-crystal X-ray diffraction, MoKα-radiation, anharmonic approximation, orthorhombic; Pna21; Z=4; 20 deg. C (a=8.444, b=7.378, c=5.146 A, 1411 F(hkl), R=0.022); 227 deg. C (a=8.616, b=7.433, c=5.063 A, 1336 F(hkl), R=0.026), 377 deg. C (a=8.746, b=7.480, c=5.013 A, 1193 F(hkl), R=0.035). A high mobility of Li atoms and their highly asymmetric vibrations are revealed. Ellipsoid of Li thermal vibrations is oviform. Li is shifted on heating to 0.26 A mainly along a-axis causing high thermal expansion in this direction; Li temperature factors are multiplied by 4 on heating. Rigid boron-oxygen groups in LiB3O5 remain practically stable on heating similar to α-Na2B8O13 and α-CsB5O8. At the same time these groups rotate relative to each other like hinges leading to extremely anisotropic thermal expansion (αa =101, αb =31, αc =-71, αv =60x10-6 deg. C-1, 20-530 deg. C, HTXRPD data). - Graphical abstract: Li anharmonic thermal vibrations in LiB3O5 crystal structures. Display Omitted

  4. Momentum densities and Compton profiles of alkali-metal atoms

    International Nuclear Information System (INIS)

    It is assumed that the dynamics of valence electrons of alkali-metal atoms can be well accounted for by a quantum-defect theoretic model while the core electrons may be supposed to move in a self-consistent field. This model is used to study the momentum properties of atoms from 3Li to 37Rb. The numerical results obtained for the momentum density, moments of momentum density and Compton profile are found to be in good agreement with the results of more detailed configuration-interaction calculations for the atom 3Li. Similar results for 11Na, 19K and 37Rb are compared with the corresponding Hartree-Fock-Roothan values only, for want of data from other realistic calculations. (author)

  5. Nano-sized Li-Fe composite oxide prepared by a self-catalytic reverse atom transfer radical polymerization approach as an anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    A novel Self-catalytic Reverse Atom Transfer Radical Polymerization (RATRP) approach that can provide the radical initiator and the catalyst by the system itself is used to synthesize a nano-sized Li-Fe composite oxide powder in large scale. Its crystalline structure and morphology have been characterized by X-ray diffraction and scanning electron microscopy. The results reveal that the composite is composed of nano-sized LiFeO2 and Fe3O4. Its electrochemical properties are evaluated by charge/discharge measurements. The results show that the Li-Fe composite oxide is an excellent anode material for lithium-ion batteries with good cycling performance (1249 mAh g-1 at 100th cycle) and outstanding rate capability (967 mAh g-1 at 5 C). Such a self-catalytic RATRP approach provides a way to synthesize nano-sized iron oxide-based anode materials industrially with preferable electrochemical performance and can also be applied in other polymer-related area.

  6. First-principles determination of the structure of NaN and NaN- clusters with up to 80 atoms.

    Science.gov (United States)

    Aguado, Andrés; Kostko, Oleg

    2011-04-28

    We have performed an extensive computational search for the global minimum (GM) structures of both neutral and anionic sodium clusters with up to 80 atoms. The theoretical framework combines basin hopping unbiased optimizations based on a Gupta empirical potential (EP) and subsequent reoptimization of many candidate structures at the density functional theory level. An important technical point is that the candidates are selected based on cluster shape descriptors rather than the relative stabilities of the EP model. An explicit comparison of the electronic density of states of cluster anions to experimental photoemission spectra suggests that the correct GM structures have been identified for all but two sizes (N = 47 and 70). This comparison validates the accuracy of the proposed methodology. Furthermore, our GM structures either match or improve over the results of previous works for all sizes. Sodium clusters are seen to accommodate strain very efficiently because: (a) many structures are based on polyicosahedral packing; (b) others are based on Kasper polyhedra and show polytetrahedral order; (c) finally, some (N + 1)-atom structures are obtained by incorporating one adatom into the outermost atomic shell of a compact N-atom cluster, at the cost of increasing the bond strain. GM structures of neutrals and anions differ for most sizes. Cluster stabilities are analyzed and shown to be dominated by electron shell closing effects for the smaller clusters and by geometrical packing effects for the larger clusters. The critical size separating both regimes is around 55 atoms. Some implications for the melting behavior of sodium clusters are discussed. PMID:21528957

  7. Production of NaCa$^+$ molecular ions in the ground state from cold atom-ion mixtures by photoassociation via an intermediate state

    CERN Document Server

    Gacesa, Marko; Michels, H Harvey; Côté, Robin

    2016-01-01

    We present a theoretical analysis of optical pathways for formation of cold Ca($^1$S)Na$^+$($^1$S) molecular ions via an intermediate state. The formation schemes are based on ab initio potential energy curves and transition dipole moments calculated using effective-core-potential methods of quantum chemistry. In the proposed approach, starting from a mixture of cold trapped Ca$^+$ ions immersed into an ultracold gas of Na atoms, (NaCa)$^+$ molecular ions are photoassociated in the excited E$^{1}\\Sigma^+$ electronic state and allowed to spontaneously decay either to the ground electronic state or an intermediate state from which the population is transferred to the ground state via an additional optical excitation. By analyzing all possible pathways, we find that the efficiency of a two-photon scheme, via either B$^{1}\\Sigma^+$ or C$^{1}\\Sigma^+$ potential, is sufficient to produce significant quantities of ground state (NaCa)$^+$ molecular ions. A single-step process results in lower formation rates that wou...

  8. Production of NaCa+ molecular ions in the ground state from cold atom-ion mixtures by photoassociation via an intermediate state

    Science.gov (United States)

    Gacesa, Marko; Montgomery, John A.; Michels, H. Harvey; Côté, Robin

    2016-07-01

    We present a theoretical analysis of optical pathways for formation of cold ground-state (NaCa) + molecular ions via an intermediate state. The formation schemes are based on ab initio potential energy curves and transition dipole moments calculated using effective-core-potential methods of quantum chemistry. In the proposed approach, starting from a mixture of cold trapped Ca+ ions immersed into an ultracold gas of Na atoms, (NaCa) + molecular ions are photoassociated in the excited E +1Σ electronic state and allowed to spontaneously decay either to the ground electronic state or an intermediate state from which the population is transferred to the ground state via an additional optical excitation. By analyzing all possible pathways, we find that the efficiency of a two-photon scheme, via either the B +1Σ or C +1Σ potential, is sufficient to produce significant quantities of ground-state (NaCa) + molecular ions. A single-step process results in lower formation rates that would require either a high-density sample or a very intense photoassociation laser to be viable.

  9. Effect of paramagnetic manganese ions doping on frequency and high temperature dependence dielectric response of layered Na1.9Li0.1Ti3O7 ceramics

    Indian Academy of Sciences (India)

    Dharmendra Pal; J L Pandey

    2010-12-01

    The manganese doped layered ceramic samples (Na1.9Li0.1)Ti3O7 : XMn(0.01 ≤ X ≤ 0.1) have been prepared using high temperature solid state reaction. The room temperature electron paramagnetic resonance (EPR) investigations exhibit that at lower percentage of doping the substitution of manganese ions occur as Mn3+ at Ti4+ sites, whereas for higher percentage of doping Mn2+ ions occupy the two different interlayer sodium/lithium sites. In both cases, the charge compensation mechanism should operate to maintain the overall charge neutrality of the lattice. The manganese doped derivatives of layered Na1.9Li0.1Ti3O7 (SLT) ceramics have been investigated through frequency dependence dielectric spectroscopy in this work. The results indicate that the dielectric losses in these ceramics are the collective contribution of electric conduction, dipole orientation and space charge polarization. Smeared peaks in temperature dependence of permittivity plots suggest diffuse nature of high temperature ferroelectric phase transition. The light manganese doping in SLT enhances the dielectric constant. However, manganese doping decreases dielectric loss due to inhibition of domain wall motion, enhances electronhopping conduction, and impedes the interlayer ionic conduction as well. Manganese doping also gives rise to contraction of interlayer space.

  10. [6-chloro-3-pyridylmethyl-3H]neonicotinoids as high-affinity radioligands for the nicotinic acetylcholine receptor: preparation using NaB3H4 and LiB3H4

    International Nuclear Information System (INIS)

    NaB3H4 and LiB3H4 at 78% and 97% isotopic enrichments, respectively, were used in the synthesis of 3H-labeled 1-(6-chloro-3-pyridyl)-methyl-2-nitromethyleneimidazolidine (CH-IMI) and N'-[(6-chloro-3-pyridyl)methyl]-n''-cyano-n'-methylacetamidine (acetamiprid) (two very potent insecticides) and of 1-(6-chloro-3-pyridyl)methyl-2-iminoimidazolidine (desnitro-IMI) (a metabolite of the commercial insecticides imidacloprid). 6-Chloronicotinoyl chloride was treated with either NaB3H4 in methanol or LiB3H4 in tetrahydrofuran and the resulting alcohol transformed to 2-chloro-5-chloromethylpyridine, which was then coupled to N-cyano-N'-methylacetamidine to give [3H] acetamiprid (45 Ci/mmol). 2-Chloro-5-chloro[3H]methylpyridine was also reacted with ethylenediamine and the product was either refluxed in absolute ethanol with 1,1-bis(methylthio)-2-nitro-ethylene to provide [3H]CH-IMI or reacted in toluene with a solution of cyanogen bromide to produce [3H] desnitro-IMI (each 55 Ci/mmol. (author)

  11. Thermodynamic properties of LiNO{sub 3}-NaNO{sub 3}-KNO{sub 3}-2KNO{sub 3}{center_dot}Mg(NO{sub 3}){sub 2} system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tao; Mantha, Divakar [Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487-0202 (United States); Reddy, Ramana G., E-mail: rreddy@eng.ua.edu [Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487-0202 (United States)

    2013-01-10

    Highlights: Black-Right-Pointing-Pointer Novel LiNO{sub 3}-NaNO{sub 3}-KNO{sub 3}-2KNO{sub 3}{center_dot}Mg(NO{sub 3}){sub 2} quaternary system was developed. Black-Right-Pointing-Pointer The melting point of the salt mixture was determined. Black-Right-Pointing-Pointer The heat capacity of the salt mixture was determined. Black-Right-Pointing-Pointer The enthalpy, entropy and Gibbs energies as function of temperature were deduced. - Abstract: A novel low melting eutectic salt was predicted in the LiNO{sub 3}-NaNO{sub 3}-KNO{sub 3}-2KNO{sub 3}{center_dot}Mg(NO{sub 3}){sub 2} quaternary system using thermodynamic modeling. The melting point of the eutectic salt was predicted to be 374.90 K. Differential scanning calorimetry (DSC) was used to experimentally determine the melting point and specific heat capacity of the quaternary system. The mixture was measured to be completely melted at 373.90 {+-} 0.78 K which is in an excellent agreement with the predicted value. The measured heat capacity data as function of temperature are fit to polynomial function. Subsequently, the thermodynamic properties such as enthalpy, entropy and Gibbs energies of this novel quaternary eutectic salt were deduced as function of temperature.

  12. Preparation and Characterization of (K0.5Na0.50.94-2xLi0.06SrxNb0.98Sb0.02O3 Lead-free Piezoelectric Ceramics

    Directory of Open Access Journals (Sweden)

    CHU Rui-Qing, HAO Ji-Gong, XU Zhi-Jun, ZANG Guo-Zhong

    2010-07-01

    Full Text Available Lead-free (K0.5Na0.50.94-2xLi0.06SrxNb0.98Sb0.02O3 (KNLSN-Srx; x=0-0.03 piezoelectric ceramics were prepared by conventional solid-state sintering process. The sintering characteristic, the microstructure, dielectric, piezoelectric and ferroelectric properties of KNLSN-Srx ceramics were investigated. XRD results show that all samples exhibite a pure perovskite phase with tetragonal symmetry, indicating that the Sr2+ has diffused into the KNLSN lattices to form a solid solution. The grain size of KNLSN-Srx ceramics was increased with the increasing of Sr-doping level. The proper sintering temperature of KNLSN-Srx ceramics shifted to higher temperature with increasing the content of Sb. Higher d33 and kp, lower tanδ and Qm were obtained as Li, Sr and Sb were added into KNN ceramics. The comprehensive good properties of doped (K0.5Na0.5NbO3 ceramics were obtained when Sr content was 2mol% (d33=130pC/N, kp=34.5%, tanδ=4.2%.

  13. A new mass value for 7Li

    CERN Document Server

    Nagy, Sz; Suhonen, M; Schuch, R; Blaum, K; Björkhage, M; Bergström, I; 10.1103/PhysRevLett.96.163004

    2012-01-01

    A high-accuracy mass measurement of 7Li was performed with the Smiletrap Penning trap mass spectrometer via a cyclotron frequency comparison of Li3+ and H2+. A new atomic mass value of 7Li has been determined to be 7.016,003,425,6,(45)u with a relative uncertainty of 0.63 ppb. It has uncovered a discrepancy as large as 14 sigma (1.1 micro u) deviation relative to the literature value given in the Atomic-Mass Evaluation AME 2003. The importance of the improved and revised 7Li mass value, for calibration purposes in nuclear-charge radii and atomic mass measurements of the neutron halos 9Li and 11Li, is discussed.

  14. β-Xenophyllite-type Na4Li0.62Co5.67Al0.71(AsO4)6

    OpenAIRE

    Riadh Marzouki; Wafa Frigui; Abderrahmen Guesmi; Mohamed Faouzi Zid; Ahmed Driss

    2013-01-01

    The title compound, tetrasodium lithium cobalt aluminium hexa(orthoarsenate), was synthesized by a solid state reaction route. In the crystal structure, Co2+ ions are partially substituted by Al3+ in an octahedral environment [M1 with site symmetry 2/m; occupancy ratio Co:Al = 0.286 (10):0.714 (10)]. The charge compensation is ensured by Li+ cations sharing a tetrahedral site with Co2+ ions [M2 with site symmetry 2; occupancy ratio Co:Li = 0.690 (5):0.310 (5)]. The ani...

  15. Solid sampling determination of lithium and sodium additives in microsamples of yttrium oxyorthosilicate by high-resolution continuum source graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Laczai, Nikoletta; Kovács, László; Péter, Ágnes; Bencs, László

    2016-03-01

    Solid sampling high resolution continuum source graphite furnace atomic absorption spectrometry (SS-HR-CS-GFAAS) methods were developed and studied for the fast and sensitive quantitation of Li and Na additives in microsamples of cerium-doped yttrium oxyorthosilicate (Y2SiO5:Ce) scintillator materials. The methods were optimized for solid samples by studying a set of GFAAS conditions (i.e., the sample mass, sensitivity of the analytical lines, and graphite furnace heating programs). Powdered samples in the mass range of 0.099-0.422 mg were dispensed onto graphite sample insertion boats, weighed and analyzed. Pyrolysis and atomization temperatures were optimized by the use of single-element standard solutions of Li and Na (acidified with 0.144 mol/L HNO3) at the Li I 610.353 nm and Na I 285.3013 nm analytical lines. For calibration purposes, the method of standard addition with Li and Na solutions was applied. The correlation coefficients (R values) of the calibration graphs were not worse than 0.9678. The limit of detection for oxyorthosilicate samples was 20 μg/g and 80 μg/g for Li and Na, respectively. The alkaline content of the solid samples were found to be in the range of 0.89 and 8.4 mg/g, respectively. The accuracy of the results was verified by means of analyzing certified reference samples, using methods of standard (solution) addition calibration.

  16. Reflectance spectroscopy of low atomic weight and Na-rich minerals: Borates, hydroxides, nitrates, nitrites, and peroxides

    Science.gov (United States)

    Cloutis, E.; Berg, B.; Mann, P.; Applin, D.

    2016-01-01

    We have measured reflectance spectra (0.35-20 μm) of a suite of minerals and synthetic compounds that contain low-Z (⩽Na) elements as the major cation and/or the major anion in oxides/oxyhydroxides, and are relevant to planetary geology and astrobiology. The suite comprises Na-borates, Na-, K-, Ca-hydroxides, nitrates, nitrites, and peroxides. Na-borate spectra exhibit B-O fundamental vibrations between 7 and 14 μm, and overtones/combinations of these bands in the 1.55, 1.75, 2.15, and 2.25 μm regions. Na-, K-, and Ca-hydroxide reflectance spectra are characterized by OH and metal-OH fundamental vibrations near 3, 8, and 18 μm, and a number of overtone and combination absorption bands at shorter wavelengths, and a characteristic metal-OH band near 2.35 μm. The nitrate and nitrite spectra exhibit fundamental N-O vibrations in the 7-14 μm region and numerous combinations and overtones that are still detectable to as low as ∼1.8 μm. Na-peroxide is largely spectrally featureless below 24 μm, making its detection problematic, while H-peroxide has many OH-related absorption features below 2.5 μm that differ in position from those of H2O ice and liquid. The results of this study indicate that the borates, hydroxides, nitrates, nitrite, and hydrogen peroxide can all be uniquely identified using characteristic absorption features that are present below 2.5 μm. However, some of these features are weak, and their detectability will depend on the types and abundances of any accessory phases that may be present.

  17. First principles study of nanostructured TiS2 electrodes for Na and Mg ion storage

    Science.gov (United States)

    Li, S. N.; Liu, J. B.; Liu, B. X.

    2016-07-01

    The development of competitive Na- and Mg-ion batteries (NIBs and MIBs) with performance comparable to Li-ion batteries is hindered by the major challenge of finding advanced electrode materials. In this work, nanostructured TiS2 electrodes including nanosheets, nanoribbons and nanotubes are shown by first principles calculations to achieve improved Na and Mg ion diffusion as compared with the bulk phase. Comparative studies between Li, Na, and Mg reveal that the diffusion kinetics of Na ions would especially benefit from the nanostructure design of TiS2. More specifically, the Na ion diffusivity turns out to be considerably higher than Li ion diffusivity, which is opposite to that observed in bulk TiS2. However, in the case of Mg ions, fast diffusion is still beyond attainment since a relatively high degree of interaction is expected between Mg and the S atoms. Edge-induced modifications of diffusion properties appear in both Na and Mg ions, while the mobility of Li ions along the ribbon edges may not be as appealing. Effects of the curvature of nanotubes on the adsorption strength and ion conductivity are also explored. Our results highlight the nanostructure design as a rich playground for exploring electrodes in NIBs and MIBs.

  18. A low temperature ultrahigh vacuum scanning tunneling microscope with high-NA optics to probe optical interactions at the atomic scale

    Science.gov (United States)

    Zhang, Haigang; Smerdon, Joseph; Suzer, Ozgun; Kersell, Heath; Guest, Jeffrey

    2015-03-01

    The optical and photophysical properties of single molecules/atoms, defects, and nanoscale structures at surfaces hinge on structure at the atomic scale. In order to characterize and control this structure and unravel these correlations, we are developing a low temperature (LT) laser-coupled ultrahigh vacuum (UHV) scanning tunneling microscope (LT Laser UHV STM) based on the Pan-style STM scanner with integrated high-numerical-aperture (NA) optics for single particle spectroscopy measurements under the STM tip. Using slip-stick inertial piezo steppers, the sample stage can be coarsely translated in X and Y directions. For optical measurements, high-NA optics behind and above the sample focus laser excitation on and collect photons emitted from the tip-sample junction. The STM is cooled by a liquid helium bath surrounded by a liquid nitrogen jacket for operation near 5 K; two separate ultrahigh vacuum chambers are used for sample preparation and STM measurements, respectively. We will describe our progress in demonstrating this instrument and plans for experiments studying the correlation between structure and optical function in nanoscale systems. U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  19. Observation of excited level populations of Li-like aluminium ions in a recombining plasma: role of atomic processes involving doubly excited levels of Be-like ions

    International Nuclear Information System (INIS)

    An aluminium slab target was irradiated by multiple pulses of Nd:glass laser light with the irradiance of 1.5x1012 W cm-2. After the laser irradiation, a laser-produced aluminium plasma was observed in its recombining phase using a spectrometer whose relative sensitivity was calibrated. We measured relative intensities of the resonance series lines and the lines of the 2p2P-nd2D and 2p2P-ns2S series of the Li-like aluminium ions and derived the excited level populations of the upper levels. >From the slope of the population distribution of the high-lying excited levels and the transition from the series lines to the continuum, the electron temperature and the electron density were estimated to be 8 eV and 3.5x1025 m-3. A comparison of the experimental population distribution with a collisional-radiative (CR) model calculation indicates that recombination of the excited Li-like ions through doubly excited levels of the Be-like ions plays an important role in the population kinetics of the Li-like ions. (author)

  20. AI-Li/SiCp composites and Ti-AI alloy powders and coatings prepared by a plasma spray atomization (PSA) technique

    Science.gov (United States)

    Khor, K. A.; Boey, F. Y. C.; Murakoshi, Y.; Sano, T.

    1994-06-01

    There has been increasing use of Al-Li alloys in the aerospace industry, due mainly to the low density and high elastic modulus of this material. However, the problem of low ductility and fracture toughness of this material has limited its present application to only weight- and stiffness-critical components. Development of Al-Li/ceramic composites is currently being investigated to enhance the service capabilities of this material. The Ti-Al alloy is also of interest to aerospace-type applications, engine components in particular, due to its attractive high-temperature properties. Preparation of fine powders by plasma melting of composite feedstock and coatings formed by plasma spraying was carried out to examine the effect of spray parameters on the microstructure and properties of these materials. Characterization of the powders and coatings was performed using the scanning electron microscope and image analyzer. Examination of the plasma-sprayed powders and coatings has shown that in the Al-Li/SiC composite there is melting of both materials to form a single composite particle. The SiC reinforcement was in the submicron range and contributed to additional strengthening of the composite body, which was formed by a cold isostatic press and consolidated by hot extrusion or hot forging processes. The plasma-sprayed Ti-Al powder showed four categories of microstructures: featureless, dendritic, cellular, and martensite-like.

  1. Measurement of the electric quadrupole moments of $^{26-29}$Na

    CERN Document Server

    Keim, M; Klein, A; Neugart, R; Neuroth, M; Wilbert, S; Lievens, P; Vermeeren, L; Brown, B A

    2000-01-01

    The nuclear electric quadrupole moments of the isotopes $^{26}$Na, $^{27}$Na, $^{28}$Na and $^{29}$Na were measured by $\\beta$-NMR spectroscopy in single crystals of LiNbO$_3$ and NaNO$_3$. High degrees of nuclear polarization were produced by optical pumping of the sodium atoms in a fast beam with a collinear laser beam.The polarized nuclei were implanted into the crystals and NMR signals were observed in the $\\beta$-decay asymmetries. Preparatory measurements also yielded improved values for the magnetic moments of $^{27-31}$Na and confirmed the spin $I=3/2$for $^{31}$Na. The results are discussed in comparison with large-basis shell-model calculations.

  2. Three-Photon Resonant Six-Wave Mixing with Phase-Conjugation Geometry in Na Atomic Vapour

    Institute of Scientific and Technical Information of China (English)

    ZUO Zhan-Chun; SUN Jiang; MI Xin; YU Zu-He; JIANG Qian; WU Ling-An; FU Pan-Ming

    2005-01-01

    @@ We report a three-photon resonant six-wave mixing (SWM) with phase- conjugation geometry. It has advantages that phase matching condition is not critical and the generation of SWM signal is efficient. This technique provides a new spectroscopic tool for studying the highly excited atomic or molecular states with high resolution.The feasibility of this technique is demonstrated in sodium vapour.

  3. X-ray Absorption Spectroscopy Characterization of a Li/S Cell

    Directory of Open Access Journals (Sweden)

    Yifan Ye

    2016-01-01

    Full Text Available The X-ray absorption spectroscopy technique has been applied to study different stages of the lithium/sulfur (Li/S cell life cycle. We have investigated how speciation of S in Li/S cathodes changes upon the introduction of CTAB (cetyltrimethylammonium bromide, CH3(CH215N+(CH33Br− and with charge/discharge cycling. The introduction of CTAB changes the synthesis reaction pathway dramatically due to the interaction of CTAB with the terminal S atoms of the polysulfide ions in the Na2Sx solution. For the cycled Li/S cell, the loss of electrochemically active sulfur and the accumulation of a compact blocking insulating layer of unexpected sulfur reaction products on the cathode surface during the charge/discharge processes make the capacity decay. A modified coin cell and a vacuum-compatible three-electrode electro-chemical cell have been introduced for further in-situ/in-operando studies.

  4. Noble gas, alkali and alkaline atoms interacting with a gold surface

    CERN Document Server

    Łach, Grzegorz; Jentschura, Ulrich D; 10.1142/S0217751X1004961X

    2013-01-01

    The attractive branch of the interaction potentials with the surface of gold have been computed for a large variety of atomic systems: the hydrogen atom, noble gases (He, Ne, Ar, Kr, Xe), alkali atoms (Li, Na, K, Rb, Cs) and alkaline atoms (Be, Mg, Ca, Sr, Ba). The results include highly accurate dynamic polarizabilities for the helium atom calculated using a variational method and explicitly correlated wavefunctions. For other atoms considered we used the data available in the literature. The interaction potentials include both the effects of retardation of the electromagnetic interactions and a realistic representation of the optical response function of gold (beyond the approximation of a perfect conductor). An explicit comparison of our result to the interaction between an atom and a perfect conductor is given.

  5. Temperature dependence of energy dissipation on NaCl(001) in non-contact atomic force microscopy

    Science.gov (United States)

    Langewisch, G.; Fuchs, H.; Schirmeisen, A.

    2010-08-01

    The dissipative tip-sample interactions are measured by dynamic force spectroscopy for silicon tips on NaCl(001) in ultrahigh vacuum in the attractive and repulsive force regimes. Force and dissipation versus distance curves were obtained for different sample temperatures ranging from 35 to 285 K. Detailed comparison in different distance regimes shows that neither the force nor energy dissipation exhibits a systematic variation with sample temperature.

  6. Može li pornografija pozitivno utjecati na žensku seksualnost? Utjecaj učestalog konzumiranja pornografije na spolni život mladih obrazovanih žena: kvalitativno istraživanje

    OpenAIRE

    Brajdić Vuković, Marija; Došen, Karmen; Ghazzawi, Lejla; Tarokić, Sonja

    2013-01-01

    Istraživanja utjecaja pornografije (seksualno eksplicitnih sadržaja) na seksualni život i zadovoljstvo uglavnom se usredotočuju na negativne posljedice konzumacije. Primjetan je i nedostatak interesa za utjecaj učestale ženske konzumacije pornografije na žensku seksualnost, pogotovo kad je on pozitivan. Ovaj se rad bavi stavovima, motivacijom i obrascima korištenja pornografije u žena mlađe životne dobi koje pornografiju učestalo koriste za vlastito seksualno zadovoljenje. Temelji se na kvali...

  7. Effect of poling temperature on piezoelectric coefficient in (Na0.52K0.4425Li0.0375)(Nb0.86Ta0.06Sb0.08)O3 ceramics

    International Nuclear Information System (INIS)

    The influence of poling temperature (Tp) on d33 and d33* of (Na0.52K0.4425Li0.0375)(Nb0.86Ta0.06Sb0.08)O3 ceramics is investigated. No notable stress is induced as there is not apparent phase transition on cooling when the ceramics are poled below orthorhombic-tetragonal phase transition temperature (To-t). However, stress emerges by phase transition when poled above To-t leading to degrade d33. Consequently, the ceramics poled near To-t exhibit the best d33 of 350 pC N-1. In addition, d33*, derived from intrinsic and extrinsic contributions, remains about the same with Tp because the ultrafine, lamellar domains could easily respond to an external electric field. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Studies of the local distortions and the EPR parameters for Cu{sup 2+} in xLi{sub 2}O-(30-x)Na{sub 2}O-69.5B{sub 2}O glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Chang-Chun; Wu, Shao-Yi; Kuang, Min-Quan; Hu, Xian-Fen; Li, Guo-Liang [Univ. of Electronic Science and Technology of China, Chengdu (China). Dept. of Applied Physics

    2016-07-01

    The local distortions and electron paramagnetic resonance (EPR) parameters for Cu2+ in lithium sodium borate (LNB) glasses xLi{sub 2}O.(30-x).Na{sub 2}O.69.5B{sub 2}O{sub 3} (5 ≤ x ≤ 25 mol%) are theoretically studied at various concentrations x in a consistent way. Owing to the Jahn-Teller effect, the [CuO{sub 6}]{sup 10-} clusters are found to experience the significant tetragonal elongations of 16% along C{sub 4} axis. Despite the nearly unchanging observed g factors, measured d-d transition band (or cubic field parameter Dq) shows remarkable linear increases with concentration x, whose influences on g {sub parallel} and g {sub perpendicular} {sub to} are actually cancelled by the linearly increasing covalency factor N and relative elongation ratio η with x. The almost unvarying hyperfine structure constants are attributed to the fact that the influences of the linearly increasing N and the linearly decreasing core polarisation constant κ largely cancel one another. The microscopic mechanisms of the above concentration dependences for these quantities are illustrated from mixed alkali effect (modification of B{sub 2}O{sub 3} network by transforming some BO{sub 3} units into BO{sub 4} ones with variations in modifier Li{sub 2}O concentration).

  9. Double layer effects in electrocatalysis: the oxygen reduction reaction and ethanol oxidation reaction on Au(111), Pt(111) and Ir(111) in alkaline media containing Na and Li cations.

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Pietro P.; Strmcnik, Dusan; Jirkovsky, Jakub S.; Connell, Justin G.; Stamenkovic, Vojislav; Markovic, Nenad

    2016-03-15

    Oxygen reduction and ethanol oxidation reactions were studied on Au(111), Pt(111) and Ir(111) in alkaline solutions containing sodium and/or lithium cations. By keeping the same (111) surface orientation and exploring oxophilicity trends and non-covalent interactions between OHad and alkali metal cations (AMCn+), we were able to gain deep insights into the multiple roles that OHad plays in these important electrocatalytic reactions. Cyclic voltammetry experiments revealed that OHad formation initiates at distinct electrode potentials, governed by the oxophilicity of the specific metal surface, with further OHad adlayer stabilization by non-covalent alkali-cation interactions and affecting the formation of a “true oxide” layer at higher electrode potentials. Although OHad is a simple spectator for the ORR, it promotes the ethanol oxidation reaction (EOR) at lower potentials and act as spectator at high OHad coverages. By changing the alkali metal cation at the interface (Li+) on more oxophilic surfaces, it was possible to promote the EOR even more, relative to Na+, without changing the product distribution for the reaction. This cation effect suggests that OHad---Li+(H2O)x clusters can stabilize the ethoxide adlayer, thus improving the EOR activity. Our results indicate the importance of the entire electrochemical interface in determining the electrocatalytic activity during reaction.

  10. A comparative study of the different sample decomposition procedures for three common lithium minerals: a scheme for the accurate elemental analysis of Li, Na, K, Rb, Cs, Mg, Ca, Mn, Al, Fe, and Ti using FAAS and ICP-AES

    International Nuclear Information System (INIS)

    An analytical procedure is developed for the elemental analysis of some lithium minerals and validated using standard reference samples of National Bureau of Standard, subsequently applied to natural lithium minerals obtained from field areas of southern region, Bangalore. The common lithium minerals are spodumene, petalite and lepidolite, and the Li2O content ranges from 4% to 8%. Three different sample decomposition procedures such as (i) fusion with ammonium bi-fluoride (ii) a mixture of ammonium bi-fluoride and ammonium sulphate and (iii) acid digestion with hydrofluoric acid and nitric acid mixture were studied and compared. Fusion with ammonium bi-fluoride was studied earlier. The elements Li, Na, K, Rb and Cs in the samples are determined by FAAS, and ICP-AES was used for other elements (Al, Fe, Mn, Mg, Ca, Ti, Be, Nb) determination. The results obtained for three international reference materials, such as, Spodumene NBS 181, Petalite, NBS 182 and Lepidolite NBS 183 are in good agreement with the recommended values, which indicates the accuracy of the proposed scheme of analysis. Authors have also estimated the values for Al, Fe, Mn, Mg, Ca, Na and K for these reference materials which were not reported earlier. The advantages of fusion with ammonium bi fluoride alone or a mixture of ammonium bi fluoride and ammonium sulphate are: (i) no alkali metal is contributed from the flux, (ii) majority of other refractory minerals which are present in minor or trace quantities were are also decomposed completely. Therefore, it gives an indication of the presence of other associated pegmatite minerals during the analysis. The proposed method is accurate and reproducibility is characterized by 2 to 5% RSD, depending on the concentration of the elements in the sample. (author)

  11. Exergy analysis of a novel air-cooled non-adiabatic absorption refrigeration cycle with NH3–NaSCN and NH3–LiNO3 refrigerant solutions

    International Nuclear Information System (INIS)

    Graphical abstract: A methodology based on the second law of thermodynamic has been carried out in the analysis of an air-cooled type ammonia/salt absorption refrigeration system. Simulation results show that Low grade energy is applicable for NH3/NaSCN and NH3/LiNO3 absorption refrigeration system under air cooling condition and relatively high exergetic efficiency can be obtained. - Highlights: • We analyze an absorption refrigeration cycle driven by low grade energy. • Modified Methodology in entropy calculation is presented. • New exergy calculation method of ammonia/salt solution is presented. • Exergy analysis under air-cooled condition is carried out. • Influence of non-adiabatic absorber to exergetic efficiency is analyzed. - Abstract: This paper presents a methodology of exergy analysis for ammonia-lithium nitrate and ammonia-sodium thiocyanate absorption refrigeration cycle which applies a novel air-cooled type non-adiabatic absorber to improve both the coefficient of performance and exegetic efficiency of the system under air cooling condition. A modified entropy calculation method for NH3/NaSCN and NH3/LiNO3 solutions is presented in this literature and different results are obtained comparing to previous research. In addition to the variation of solution temperature and pressure from specific working state to the reference state, the variation of solution concentration, which was always neglected by previous researchers in ammonia/salt solution exergy calculation, has been taken into account while analyzing the least potential of ammonia/salt solution for doing useful work, and a corresponding approach for specific exergy calculation is presented. The effects of generator temperature, absorber outlet temperature, absorber efficiency and other system parameters on system exergetic efficiency have been discussed in this study. Analysis results indicate that relatively high system performance can be obtained by air-cooled type ammonia

  12. Li-promoted sodium zirconate as a CO{sub 2} absorbent at high temperatures; Zirconato de sodio promovido con Li como absorbente de CO{sub 2} a alta temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Guzman Velderrain, V.; Barraza Jimenez, D.; Lardizabal Gutierrez, D.; Delgado Vigil, D.; Salinas Gutierrez, J.; Lopez Ortiz, A.; Collins-Martinez, V. [Centro de Investigacion en Materiales Avanzados S. C., Chihuahua, Chihuahua (Mexico)]. E-mail: virginia.collins@cimav.edu.mx

    2009-09-15

    In processes to produce hydrogen from fossil fuels, CO{sub 2} capture at high temperatures has played a crucial role in their conversion into energy-efficient processes. One example is steam reformer methane improved with absorption (SER), where CO{sub 2} capture at high temperatures (600 degrees Celsius) provides an energy savings of {approx_equal} 23% over conventional reformer processes (SMR). An important part of this concept is solid CO{sub 2} absorption, which must have adequate absorption capacity and rapid absorption/regeneration kinetics. Recently, synthetic CO{sub 2} absorbents have been developed that consist of mixed Li oxides. Previous studies conducted in our laboratory report that the absorption/regeneration properties of sodium zirconate (Na{sub 2}ZrO{sub 3}) are higher than Li-oxides. The objective of the present work is to increase the absorption capacity of Na{sub 2}ZrO{sub 3} at high temperatures without significantly affecting the kinetics of its absorption and regeneration, with Li promotion. The Na{sub 2}ZrO{sub 3} was synthesized by reaction in a solid state and impregnated with LiNO{sub 3} at different Li/Na ratios: 0, 0.03, 0.05, 0.1 and 0.25 (NZ, NZL3, NZL5, NZL10, NZL25). The characterization consisted of XRD and SEM. The evaluation as an absorbent was performed with TGA at 600 degrees Celsius in 80% CO{sub 2} (absorption) and 800 degrees Celsius in air (regeneration). While XRD shows only the Na{sub 2}ZrO{sub 3} structure in all the samples, the promoted samples present a signal shift with respect to Na{sub 2}ZrO{sub 3}, which is attributed to the substitution of Na atoms with Li. The TGA results indicate that the addition of Li to the Na{sub 2}ZrO{sub 3} structure does not significantly modify the absorption or regeneration kinetics. As the Li contents in the Na{sub 2}ZrO{sub 3} increase, the amount of CO{sub 2} capture increases up to a limit between 10 and 25% mol of Li. This is due to the displaced sodium presumably tending to form

  13. Transition probabilities for lines of Cr II, Na II and Sb I by laser produced plasma atomic emission spectroscopy; Probabilidades de transicion de algunos niveles de Cr II, Na II y Sb I medediante espectroscopia de plasma producidos por laser

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A. M.; Ortiz, M.; Campos, J.

    1995-07-01

    Absolute transition probabilities for lines of CR II, Na II and Sb I were determined by emission spectroscopy of laser induced plasmas. the plasma was produced focusing the emission of a pulsed Nd-Yag laser on solid samples containing the atom in study. the light arising from the plasma region was collected by and spectrometer. the detector used was a time-resolved optical multichannel analyzer (OMA III EG and G). The wavelengths of the measured transitions range from 2000 sto 4100 A. The spectral resolution of the system was 0. 2 A. The method can be used in insulators materials as Cl Na crystals and in metallic samples as Al-Cr and Sn-Sn alloys. to avoid self-absorption effects the alloys were made with low Sb or Cr content. Relative transition probabilities have been determined from measurements of emission-line intensities and were placed on an absolute scale by using, where possible, accurate experimental lifetime values form the literature or theoretical data. From these measurements, values for plasma temperature (8000-24000 K), electron densities ({approx}{approx} 10''16 cm ''-3) and self-absorption coefficients have been obtained. (Author) 56 refs.

  14. Mikrobna proizvodnja antioksidativnih dodataka hrani na čvrstoj podlozi od kore šipka (Punica granatum) i lišća grma Larrea tridentata

    OpenAIRE

    Aguilar, Cristóbal Noé; Aguilera-Carbo, Antonio; Robledo, Armando; Ventura, Janeth; Belmares, Ruth; Martinez, Diego; Rodríguez-Herrera, Raul; Contreras, Juan

    2008-01-01

    U radu je istražena mogućnost primjene lišća grma Larrea tridentata i kore šipka (Punica granatum) kao sirovina za dodatak čvrstim podlogama te proizvodnju antioksidanasa. U središtu je istraživanja kinetička procjena fizikalno-kemijskih promjena tih taninima bogatih sirovina, ističući promjenu udjela polifenolnih spojeva tijekom procesa. Za proces je upotrijebljen soj plijesni Aspergillus niger GH1, koji je praćen tijekom 96 sati. Određen je udio proteina, sirovih vlakana, lipida, te ukupnih...

  15. Quantitative analysis of sodium di-uranate for Al, Ca, Fe, Mg, Mn, Na by flame-atomic absorption spectrometric method

    International Nuclear Information System (INIS)

    Nuclear Fuel Complex (NFC) receives Sodium Di-Uranate (SDU) from Uranium Corporation of India Limited (UCIL) for producing sinterable UO2 pellets for manufacturing fuel sub assemblies. Several impurities present in ore find their way into SDU during its conversion. Stringent specification have been laid down by the reactor designs for achieving the optimum performance of the fuel and several impurity element like Al, Ca, Fe, Mg, Mn, Na among others affects severely performance of UO2 fuel. Most of the impurity including the above mentioned elements are generally analysed by ICP-OES method. However, determination of Al, Ca, Fe, Mg, Mn and Na by ICP-OES requires lot of dilution as they are present at high levels in SDU. Apart from introducing dilution error, dilution process is very tedious and time consuming work and not a preferred choice in an industrial lab like control lab where large analytical load exists and time bound analysis is a requirement. To avoid these difficulties a simple and reliable Flame Atomic absorption spectrometric technique has been developed for regular analysis. Present method involves dissolution of SDU sample in Conc. HNO3 and after the complete dissolution the sample solution has been evaporated to near dryness on a hot plate. Subsequently sample solution has been brought into 4N HNO3 medium

  16. Quantum effects in the case of (6)Li+ and (7)Li+ ions evolving in a neutral (6)Li gas at a wide range of temperatures.

    Science.gov (United States)

    Bouchelaghem, F; Bouledroua, M

    2014-02-01

    This work deals with the quantum-mechanical calculation of the temperature-dependent mobility of ionic lithium atoms diffusing in their parent gas. The computation of the quantal phase shifts in connection with the gerade and ungerade potential-energy curves, through which Li(+) approaches Li(2s), leads to the computation of the charge-transfer and diffusion cross sections. The behavior of the coefficients of diffusion and mobility with temperature is also examined. Throughout this work, the isotopic effects in the (6)Li(+)-(6)Li and (7)Li(+)-(6)Li collisions are emphasized. PMID:24326775

  17. RETRACTED: Crystal structures of XnB12H12 (X = Li, K, Ca) and hydrogen storage property of Na-(Li, K, Ca)-B-H system from first principles calculation

    Science.gov (United States)

    YaJuan, Guo; JianFeng, Jia; XiaoHua, Wang; Ying, Ren; HaiShun, Wu

    2013-02-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor-in-Chief.The Authors have plagiarized part of a paper that had already appeared in: V. Ozolins, E. H. Majzoub and C. Wolverton, First-Principles Prediction of Thermodynamically Reversible Hydrogen Storage Reactions in the Li-Mg-Ca-B-H System, J. Am. Chem. Soc. 131 (2009) 230-237; DOI:http://dx.doi.org/10.1021/ja8066429.One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  18. Charge transfer activation energy for alkali atoms on Re and Ta

    Science.gov (United States)

    Gładyszewski, Longin

    1993-09-01

    Ion and atom desorption energies for five alkali metals on Re and Ta were determined using the ion thermal emission noise method. The activation energies for the charge transfer process in the adsorbed state were calculated using a special energetic balance equation, which describes the surface ionization and thermal desorption effect. Energies for desorption of Li, Na, K, Rb and Cs from Re and Ta surfaces were determined by measuring the time autocorrelation function of the ion thermoemission current fluctuations.

  19. ISKANJE NEPOKRITIH DELOV TERENA V PODATKIH LiDAR

    OpenAIRE

    Osojnik, Monika

    2013-01-01

    LiDAR je sodobna tehnologija daljinskega zaznavanja, ki s pomočjo laserske svetlobe omogoča hitro in natančno zajemanje podatkov o zemeljskem površju in objektih na njem. Zaradi slabe odbojnosti svetlobe na vodnih področjih in zaradi ovir, ki zakrivajo okolico, sistemi LiDAR pogosto ne zajamejo celovite slike površja. Zaradi kasnejših prostorskih analiz, temelječih na podatkih LiDAR, je smiselno takšne dele v podatkih LiDAR pravočasno odkriti in odpraviti. V tem diplomskem delu predstavlja...

  20. Lithiotantite, ideally LiTa3O8

    Directory of Open Access Journals (Sweden)

    Aba C. Persiano

    2012-05-01

    Full Text Available Lithiotantite (lithium tritantalum octaoxide and lithiowodginite are natural dimorphs of LiTa3O8, corresponding to the laboratory-synthesized L-LiTa3O8 (low-temperature form and M-LiTa3O8 (intermediate-temperature form phases, respectively. Based on single-crystal X-ray diffraction data, this study presents the first structure determination of lithiotantite from a new locality, the Murundu mine, Jenipapo District, Itinga, Minas Gerais, Brazil. Lithiotantite is isotypic with LiNb3O8 and its structure is composed of a slightly distorted hexagonal close-packed array of O atoms stacked in the [-101] direction, with the metal atoms occupying half of the octahedral sites. There are four symmetrically non-equivalent cation sites, with three of them occupied mainly by (Ta5+ + Nb5+ and one by Li+. The four distinct octahedra share edges, forming two types of zigzag chains (A and B extending along the b axis. The A chains are built exclusively of (Ta,NbO6 octahedra (M1 and M2, whereas the B chains consist of alternating (Ta,NbO6 and LiO6 octahedra (M3 and M4, respectively. The average M1—O, M2—O, M3—O and M4—O bond lengths are 2.011, 2.004, 1.984, and 2.188 Å, respectively. Among the four octahedra, M3 is the least distorted and M4 the most. The refined Ta contents at the M1, M2 and M3 sites are 0.641 (2, 0.665 (2, and 0.874 (2, respectively, indicating a strong preference of Ta5+ for M3 in the B chain. The refined composition of the crystal investigated is Li0.96Mn0.03Na0.01Nb0.82Ta2.18O8.

  1. GRUČENJE PODATKOV LiDAR

    OpenAIRE

    Založnik, Boštjan

    2014-01-01

    Cilje diplomske naloge je raziskati možnosti uporabe algoritmov gručenja za obdelavo podatkov LiDAR. Prvi del diplomske naloge predstavlja podatke LiDAR in algoritme gručenja. S senzorji LiDAR, pritrjenimi na letala ali helikopterje, je omogočeno hitro in natančno modeliranje površja. Metode gručenje predstavljajo enega izmed pristopov za detekcijo objektov na površju. Gručenje je vrsta nenadzorovane klasifikacije podatkov. Za učinkovito implementacijo algoritmov gručenja so po...

  2. Improvement orange–red emitting by codoping A{sup +} (A=Li, Na, K) in Ca{sub 2}BO{sub 3}Cl:Sm{sup 3+}phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhijun, E-mail: wangzhijunmail@yahoo.com.cn [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Li, Panlai; Zhang, Xing; Li, Qingxuan; Li, Ting; Yang, Zhiping; Guo, Qinglin [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2013-04-01

    Sm{sup 3+} doped Ca{sub 2}BO{sub 3}Cl with different charge compensation approaches are synthesized by a high temperature solid state reaction method, and systematically characterized by the luminescent properties and the CIE chromaticity coordinates. All the samples show the characteristics orange–red emission of Sm{sup 3+} ion with good CIE chromaticity coordinates. When codoped Li{sup +}, Na{sup +}, K{sup +} as charge compensators, the relative emission intensities of Ca{sub 2}BO{sub 3}Cl:Sm{sup 3+} are increased to 1.57, 1.99 and 1.78 times that of the direct charge balance. The difference is considered to be due to the different ion radii effect on the crystal field of Sm{sup 3+} ions. The results indicate that Na{sup +} ion may be the optimal compensation charge for Ca{sub 2}BO{sub 3}Cl:Sm{sup 3+}.

  3. The start-up and observation of the Li target in the EVEDA Li test loop

    International Nuclear Information System (INIS)

    Highlights: • The EVEDA Li test loop (ELTL) is a major Japanese activity for the validation of the Li target facility for the IFMIF. • The first operational results of the Li target in the ELTL are obtained. • The start-up procedure of the Li target was examined and consequently achieved. • The Li target whose velocity was 20 m/s in pressurized and vacuum conditions was observed by image devices and confirmed to be stable. - Abstract: Engineering Validation and Engineering Design Activities (EVEDA) for the International Fusion Materials Irradiation Facility (IFMIF) have been carried out under the “Broader Approach” (BA) agreement. As a major activity for the Li target facility, the EVEDA Li test loop (ELTL) was constructed at the Japan Atomic Energy Agency's Oarai site to validate the hydraulic conditions of the IFMIF Li target. This paper presents the first operational results of the Li target in the ELTL. A series of tests were performed to check the operational performance of the Li target. The conclusions are as follows: (1) the start-up procedure of the Li target was examined and consequently achieved the Li target and (2) the Li target whose velocity was 20 m/s under pressurized and vacuum conditions was observed by image devices and confirmed to be stable

  4. Transition metal NaMF3 compounds as model systems for studying the feasibility of ternary Li-M-F and Na-M-F single phases as cathodes for lithium–ion and sodium–ion batteries

    International Nuclear Information System (INIS)

    The high electronegativity of fluorine suggests that fluorides may enable cathode materials for lithium–ion and sodium–ion batteries with higher voltage profiles for insertion or larger capacities for conversion. Iron has traditionally been studied as a redox center in fluorine-based cathodes, but the other metals have rarely been investigated. We demonstrate that the NaMF3 series (M = Mn, Fe, Co, Ni, Cu) offers a convenient means to compare the feasibility of the first row transition metals employed as fluorine-based cathodes for sodium–ion and lithium–ion batteries. NaFeF3 was found to be the only electrochemically active compound, which is able to undergo reversible Na+ reinsertion. This is ascribed to: (i) the chemical nature of the charged state FeF3 which is the only fluorine acceptor and chemically the most stable compound among the other MF3 and (ii) the existence of two FeF3 polymorphs with closer structural resemblance to the parent NaFeF3, which may contribute to the rigidity of the parent NaFeF3 structure during desodiation

  5. Momentum densities and Compton profiles of alkali-metal atoms

    Indian Academy of Sciences (India)

    Pranab Sarkar; Anupam Sarkar; S N Roy; B Talukdar

    2003-03-01

    It is assumed that the dynamics of valence electrons of alkali-metal atoms can be well accounted for by a quantum-defect theoretic model while the core electrons may be supposed to move in a self-consistent field. This model is used to study the momentum properties of atoms from 3Li to 37Rb. The numerical results obtained for the momentum density, moments of momentum density and Compton profile are found to be in good agreement with the results of more detailed configuration-interaction calculations for the atom 3Li. Similar results for 11Na, 19K and 37Rb are compared with the corresponding Hartree–Fock–Roothaan values only, for want of data from other realistic calculations.

  6. New intermetallic phases in the Cu-Li-Sn system. The lithium-rich phases Li3CuSn and Li6Cu2Sn3

    International Nuclear Information System (INIS)

    The Li-rich ternary intermetallic compounds with the idealized end-member compositions Li3CuSn (CSD-427099) and Li6Cu2Sn3 (CSD-427100) were synthesized from the pure elements by induction melting in Ta crucibles and annealing at 400 circle C. Both powder and single-crystal XRD investigations were performed. Li3CuSn crystallizes in space group P6/mmm [a=4.5769(2), c=8.461(2) Aa; wR2=0.073 for 180 unique F2-values and 25 free variables]. All atoms are located along [00z], [1/3 2/3 z] and [2/3 1/3 z]; individual sites are arranged in layers parallel to (00.1). One site is fully, one partially occupied by Sn atoms. Fully but mixed occupation with Cu and Li atoms was found for one site. The remaining electron-density distribution resulting from the strong anisotropic displacement parallel to the c axis is considered in four further sites, which are mixed occupied with (Li, Cu, □), but modelled solely by Li atoms. The crystal structure exhibits analogies with that of Li2CuSn (F anti 43m); comparable layers occur parallel to {111} but the stacking sequence and packing density differs adopting cubic symmetry. In Li6Cu2Sn3 [space group R anti 32/m, a=4.5900(2), c=30.910(6) Aa; wR2=0.039 for 253 unique F2-values for 25 free variables] all atoms are arranged again at (00z), (1/3 2/3 z) and (2/3 1/3 z). Three sites are fully occupied (two by Sn atoms, a further one by Li atoms). Three additional positions are mixed occupied by Cu and Li atoms. The crystal structure is closely related to that of the binary phases Li13Sn5 and Li5Sn2; the substitution of Li by Cu atoms and vice versa is evident. The structural relationship to Li13Ag5Si6, which is permeable for Li ions, makes the title compound interesting as anode material in Li-ion batteries.

  7. Thermodynamic properties of Li, Pb and Li17Pb83 with molecular dynamics simulations

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: In this work, new EAM potentials for Li, Pb and Li–Pb alloy have been constructed. Based on these potentials, the structural, thermodynamic and diffusion properties of Li, Pb and Li17Pb83 have been studied with molecular dynamics simulations. The calculated radial distribution functions and static structure factors agree well with previous reported data. The partial radial distribution functions indicate that liquid Li17Pb83 shows a hetero-coordination tendency and the partial Bhatia–Thornton structure factor SCC(q) suggests the concentration fluctuation in Li17Pb83 is not large. As comparing to the self-diffusion coefficients, the component diffusion coefficients are much smaller for Li atoms, and almost the same for Pb atoms. Density, enthalpy, capacity, melting point, latent heat of fusion and surface tension are also in reasonable agreement with the literature data within the experimental error

  8. Spatial atomic layer deposition on flexible porous substrates: ZnO on anodic aluminum oxide films and Al{sub 2}O{sub 3} on Li ion battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Kashish [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States); Routkevitch, Dmitri; Varaksa, Natalia [InRedox, Longmont, Colorado 80544 (United States); George, Steven M., E-mail: Steven.George@Colorado.Edu [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 and Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States)

    2016-01-15

    Spatial atomic layer deposition (S-ALD) was examined on flexible porous substrates utilizing a rotating cylinder reactor to perform the S-ALD. S-ALD was first explored on flexible polyethylene terephthalate polymer substrates to obtain S-ALD growth rates on flat surfaces. ZnO ALD with diethylzinc and ozone as the reactants at 50 °C was the model S-ALD system. ZnO S-ALD was then performed on nanoporous flexible anodic aluminum oxide (AAO) films. ZnO S-ALD in porous substrates depends on the pore diameter, pore aspect ratio, and reactant exposure time that define the gas transport. To evaluate these parameters, the Zn coverage profiles in the pores of the AAO films were measured using energy dispersive spectroscopy (EDS). EDS measurements were conducted for different reaction conditions and AAO pore geometries. Substrate speeds and reactant pulse durations were defined by rotating cylinder rates of 10, 100, and 200 revolutions per minute (RPM). AAO pore diameters of 10, 25, 50, and 100 nm were utilized with a pore length of 25 μm. Uniform Zn coverage profiles were obtained at 10 RPM and pore diameters of 100 nm. The Zn coverage was less uniform at higher RPM values and smaller pore diameters. These results indicate that S-ALD into porous substrates is feasible under certain reaction conditions. S-ALD was then performed on porous Li ion battery electrodes to test S-ALD on a technologically important porous substrate. Li{sub 0.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} electrodes on flexible metal foil were coated with Al{sub 2}O{sub 3} using 2–5 Al{sub 2}O{sub 3} ALD cycles. The Al{sub 2}O{sub 3} ALD was performed in the S-ALD reactor at a rotating cylinder rate of 10 RPM using trimethylaluminum and ozone as the reactants at 50 °C. The capacity of the electrodes was then tested versus number of charge–discharge cycles. These measurements revealed that the Al{sub 2}O{sub 3} S-ALD coating on the electrodes enhanced the capacity stability. This S

  9. Facebook’ta Bulunma Amacı ve Facebook Reklamlarına Duyulan İlgi Arasındaki İlişki

    OpenAIRE

    Ay, Arş. Grv. Ufuk

    2014-01-01

    Bu araştırmada Facebook’ta bulunma amaçları ile Facebook reklamlarına duyulan ilgi arasında bir ilişki olup olmadığı ölçülmüştür. Bu amaçla internet üzerinden 283 kişiye anket uygulanmıştır. Araştırmanın bulguları Facebook’ta bulunma amaçları olarak tanımlanan “sosyal arama” ve “sosyal tarama” değişkenleriyle Facebook reklamlarına duyulan ilgi arasında anlamlı ilişkiler olduğunu destekler niteliktedir.

  10. First-Principles Study of LiPON Solid Electrolyte

    Science.gov (United States)

    Santosh, K. C.; Xiong, Ka; Cho, Kyeongjae

    2011-03-01

    There has been much interest in the thin-film solid electrolyte for solid state battery and ionics applications. LiPON is a representative material developed by Oak Ridge National Laboratory. In this work, we use first principles calculations based on the density functional theory to investigate the Li- ion migration mechanisms of LiPON family materials. We investigate atomic structures, electronic structures and defect formation energies of these materials. To determine the migration path of Li diffusion, the activation energies are calculated. This study helps us to understand fundamental mechanisms of Li-ion migration and to improve Li ion conductivity in the solid electrolytes.

  11. A quem confiamos os recursos comuns - estado, comunidade ou mercado? - lições aprendidas com o manejo da pesca na Amazônia

    Directory of Open Access Journals (Sweden)

    Antonio Oviedo

    2003-12-01

    Full Text Available A ausência de práticas de manejo sustentável da base comum de recursos naturais é decorrente de várias causas, tais como: insegurança fundiária, instituições locais pouco representativas, políticas públicas inadequadas para a gestão participativa e ausência de incentivos e créditos adequados. Este modelo de exploração dos recursos comuns tem provocado a degradação ambiental e conflitos sociais entre os diversos usuários do recurso. Este artigo trata do uso e conservação da base comum de recursos naturais, visando fornecer subsídios para uma avaliação da gestão ambiental na Amazônia e do papel das estruturas institucionais. O artigo apresenta experiências de gestão ambiental da pesca na Amazônia, com ênfase na participação das comunidades locais organizadas, as quais apontam novas possibilidades para os processos de tomada de decisão, fortalecendo um sistema descentralizado, e configurando um marco regulatório da gestão ambiental participativa.

  12. Pressure-induced non-superconducting phase of β-Na0.33V2O5 and the mechanism of high-pressure phase transitions in β-Na0.33V2O5 and β-Li0.33V2O5 at room temperature

    Science.gov (United States)

    Grzechnik, A.; Ueda, Y.; Yamauchi, T.; Hanfland, M.; Hering, P.; Potapkin, V.; Friese, K.

    2016-01-01

    The crystal structure of β-Na0.33V2O5 (C2/m, Z  =  6) has been studied on compression to 19 GPa at room temperature using synchrotron single-crystal diffraction in a diamond anvil cell. The vanadate bronze undergoes a phase transition to a non-superconducting phase at about 12 GPa due to changes of polyhedral connectivities in the vanadate framework and due to ordering of the Na+ cations. This novel structure (Cm, Z  =  6) is interpreted as an intermediate stage in the sequence of pressure-induced transformations in the β-A 0.33V2O5 bronzes (A: Li, Na) at room temperature. This study reveals the close relation between the loss of the two-leg ladder V-V system and non-superconducting state of the β-A 0.33V2O5 materials.

  13. Je li sustav sporta pravedan?

    OpenAIRE

    Perman, Biserka

    2011-01-01

    Pod pojmom morala, etike i ferpleja u sportu, obično se misli na provedbu trenažnog procesa i natjecanja kroz poštovanje pravila igre, suparnika, organizatora, voditelja i sudaca, kroz primjenu standarda korištenih sredstava, sprava i pribora koji se koriste u natjecanjima te izbjegavanje i sprječavanje upotrebe nedozvoljenih stimulativnih sredstava, odnosno dopinga. No, postavlja se pitanje je li sam sustav sporta u startu postavljen pravedno i moralno. Pojavljuje li se neravnopravnost i dis...

  14. Lições em engenharia social: a lógica da matriz de projeto na cooperação internacional

    OpenAIRE

    Catarina Morawska Vianna

    2014-01-01

    Este artigo explora os princípios da engenharia social que embasam o trabalho das agências internacionais de desenvolvimento. A partir de um relato etnográfico de um treinamento na Catholic Agency for Overseas Development, a agência católica de desenvolvimento internacional da Inglaterra e País de Gales, será apresentado o pensamento lógico da matriz de projeto a partir do qual os técnicos da organização são incitados a operar. Argumenta-se que o fracasso crônico dos projetos, em geral atribu...

  15. (6)Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Alam, T.M.; Boyle, T.J.; Brow, R.K.; Conzone, S.

    1999-02-08

    {sup 6}Li and {sup 7}Li solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the local coordination environment of lithium in a series of xLi{sub 2}O {center_dot} (1-x)P{sub 2}O{sub 5} glasses, where 0.05 {le} x {le} 0.55. Both the {sup 6}Li and {sup 7}Li show chemical shift variations with changes in the Li{sub 2}O concentration, but the observed {sup 6}Li NMR chemical shifts closely approximate the true isotropic chemical shift and can provide a measure of the lithium bonding environment. The {sup 6}Li NMR results indicate that in this series of lithium phosphate glasses the Li atoms have an average coordination between four and five. The results for the metaphosphate glass agree with the coordination number and range of chemical shifts observed for crystalline LiPO{sub 3}. An increase in the {sup 6}Li NMR chemical shift with increasing Li{sub 2}O content was observed for the entire concentration range investigated, correlating with increased cross-linking of the phosphate tetrahedral network by O-Li-O bridges. The {sup 6}Li chemical shifts were also observed to vary monotonically through the anomalous glass transition temperature (T{sub g}) minimum. This continuous chemical shift variation shows that abrupt changes in the Li coordination environment do not occur as the Li{sub 2}O concentration is increased, and such abrupt changes can not be used to explain the T{sub g} minimum.

  16. Theoretical atomic and molecular physics: Progress report, July 1, 1988 through June 30, 1989

    International Nuclear Information System (INIS)

    The theoretical atomic and molecular physics program at Rice University emphasizes fundamental questions regarding the structure and collision dynamics of various atomic and molecular systems with some attention given to atomic processes at surfaces. Our activities have been centered on continuing the projects initiated last year as well as beginning some new studies. These include: differential elastic and charge-transfer scattering and alignment and orientation of the excited electron cloud in ion-atom, atom-atom and ion-molecule collisions, using a molecular-orbital representation and both semiclassical and quantal methods; quenching of low-lying Rydberg states of a sodium atom in a collision with a rare-gas atom, using a semiclassical representation; so far, target atoms He, Ne and Ar have been studied; chemiionization and ion-pair formation in a collision of a Li atom with a metastable He atom at intermediate collision energies, using a combination of quantal and semi-classical methods; Penning ionization of alkali atoms Na and K, using advanced Cl and Stieltjes imaging methods; radiative and nonradiative charge-transfer in He+ + H collisions at ultra-low collision energies, using quantal methods; elastic and inelastic processes in electron-molecule collisions, using the continuum-multiple-scattering method; and inelastic collision processes in dense, high-temperature plasmas. Selected highlights of our research progress are briefly summarized in this paper

  17. MULTIPLY CHARGED IONS COLLISIONS WITH ATOMS INTO EXCITED STATES

    Institute of Scientific and Technical Information of China (English)

    PanGuangyan

    1990-01-01

    The emission spectra in collisions between Ions and Atoms have been measured by an Optical Multichannel Analysis System (OMA).The experimental results demonstrate that there are two channels of excitation in collision between single charged ions and atoms and three channels of excitation in collision between double charged ions and atoms.Emission cross cestions and excitation cross sections have been obtained.K.Kadota et al and R.Shingal et al suggested that,under the appropriate conditions,the H42+-Li and He2++Na collision systems can be used efficiently to produce a laser of Lyman-α(30,4nm) and Lyman-β(25.6nm)lines via cascade to He+(2P)state.

  18. Flexible High-Performance Lead-Free Na0.47K0.47Li0.06NbO3 Microcube-Structure-Based Piezoelectric Energy Harvester.

    Science.gov (United States)

    Gupta, Manoj Kumar; Kim, Sang-Woo; Kumar, Binay

    2016-01-27

    Lead-free piezoelectric nano- and microstructure-based generators have recently attracted much attention due to the continuous demand of self-powered body implantable devices. We report the fabrication of a high-performance flexible piezoelectric microgenerator based on lead-free inorganic piezoelectric Na0.47K0.47Li0.06NbO3 (NKLN) microcubes for the first time. The composite generator is fabricated using NKLN microcubes and polydimethylsiloxane (PDMS) polymer on a flexible substrate. The flexible device exhibits excellent performance with a large recordable piezoelectric output voltage of 48 V and output current density of 0.43 μA/cm(2) under vertical compressive force of 2 kgf, for which an energy conversion efficiency of about 11% has been achieved. Piezoresponse and ferroelectric studies reveal that NKLN microcubes exhibited high piezoelectric charge coefficient (d33) as high as 460 pC/N and a well-defined hysteresis loops with remnant polarization and coercive field of 13.66 μC/cm(2) and 19.45 kV/cm, respectively. The piezoelectric charge generation mechanism from NKLN microgenerator are discussed in the light of the high d33 and alignment of electric dipoles in polymer matrix and dielectric constant of NKLN microcubes. It has been demonstrated that the developed power generator has the potential to generate high electric output power under mechanical vibration for powering biomedical devices in the near future. PMID:26735739

  19. Calculation of NaCl, KCl and LiCl Salts Activity Coefficients in Polyethylene Glycol (PEG4000)-Water System Using Modified PHSC Equation of State, Extended Debye-Hückel Model and Pitzer Model

    Science.gov (United States)

    Marjani, Azam

    2016-07-01

    For biomolecules and cell particles purification and separation in biological engineering, besides the chromatography as mostly applied process, aqueous two-phase systems (ATPS) are of the most favorable separation processes that are worth to be investigated in thermodynamic theoretically. In recent years, thermodynamic calculation of ATPS properties has attracted much attention due to their great applications in chemical industries such as separation processes. These phase calculations of ATPS have inherent complexity due to the presence of ions and polymers in aqueous solution. In this work, for target ternary systems of polyethylene glycol (PEG4000)-salt-water, thermodynamic investigation for constituent systems with three salts (NaCl, KCl and LiCl) has been carried out as PEG is the most favorable polymer in ATPS. The modified perturbed hard sphere chain (PHSC) equation of state (EOS), extended Debye-Hückel and Pitzer models were employed for calculation of activity coefficients for the considered systems. Four additional statistical parameters were considered to ensure the consistency of correlations and introduced as objective functions in the particle swarm optimization algorithm. The results showed desirable agreement to the available experimental data, and the order of recommendation of studied models is PHSC EOS > extended Debye-Hückel > Pitzer. The concluding remark is that the all the employed models are reliable in such calculations and can be used for thermodynamic correlation/predictions; however, by using an ion-based parameter calculation method, the PHSC EOS reveals both reliability and universality of applications.

  20. Phase transitions and optical characterization of lead-free piezoelectric (K0.5Na0.5)0.96Li0.04(Nb 0.8Ta0.2)O3 thin films

    KAUST Repository

    Yao, Yingbang

    2013-06-01

    Lead-free piezoelectric thin films, (K0.5Na0.5) 0.96Li0.04(Nb0.8Ta0.2)O 3, were epitaxially grown on MgO(001) and Nb-doped SrTiO 3(001) substrates using pulsed laser deposition. The optimum deposition temperature was found to be 600 C. Two types of in-plane orientations were observed in the films depending on the substrates used. The transmittance and photoluminescence spectra as well as the dielectric and ferroelectric properties of the films were measured. The measured band-gap energy was found to be decreased with the deposition temperature. The dielectric constant decreased from 550 to 300 as the frequency increased from 100 Hz to 1 MHz. The measured remnant polarization and coercive field were 4 μC/cm2 and 68 kV/cm, respectively. The phase transitions of the films were studied by Raman spectroscopy. Two distinct anomalies originating from the cubic-to-tetragonal (TC-T ~ 300 C) and tetragonal-to-orthorhombic (TT-O ~ 120 C) phase transitions were observed. Our results show that Raman spectroscopy is a powerful tool in identifying the phase transitions in ferroelectric thin films. © 2013 Elsevier B.V.

  1. Simultaneous melting of shell and core atoms, a molecular dynamics study of lithium–copper nanoalloys

    International Nuclear Information System (INIS)

    Melting of nanoalloys originates from the alloy surface and gradually propagates into the interior region. The thermal stability of Li cores and Cu shells nanoalloy with size of 3.5 nm is studied through molecular dynamics and embedded atom method with the use of potential energy, Lindemann index, and radial distribution function. Results show that the shell and core Li atoms are melted in two steps: first, some Li atoms in the core migrate to the nanoalloy surface and maintain a typical solid state despite that the system temperature is higher than the bulk melting point of Li because of Li solidification in the solid–liquid interface; second, the shell and core Li atoms are simultaneously melted at high temperatures. A comparative study of Li@Cu nanoalloys with different Li atomic numbers shows that thermal stability is enhanced with the decreasing number of Li atoms within the nanoalloys because of weak binding for Cu thin shells

  2. Novel synergistic 0.9LiMn0.9Fe0.1PO4·0.1Na3V2(PO4)2F3/C nano-hybrid cathode with enhanced electrochemical performance for lithium-ion batteries

    Science.gov (United States)

    Zhang, Zhijian; Hu, Guorong; Cao, Yanbing; Duan, Jianguo; Du, Ke; Peng, Zhongdong

    2016-01-01

    The nanostructured 0.9LiMn0.9Fe0.1PO4·0.1Na3V2(PO4)2F3/C composites are successfully synthesized by a facile solvothermal method followed by mechanical activation and subsequent carbonthermal reduction process. Behaviours of bi-phase co-existence and element mutual-substitution have been investigated by XRD, TEM/EDX and FTIR. The result shows that the composites have dual phase boundaries including the semi-coherent phase interface and incoherent phase interface, as well as the advantage of Na3V2(PO4)2F3 acting as ionic conductor. Due to the multifunctional phase and (Mn,Fe)-V mutual doping as well as nano-carbon continual conducting network, enhanced Li+ migration and charge transfer of nano-hybrid is obtained. Compared with pristine one, the 0.9LiMn0.9Fe0.1PO4·0.1Na3V2(PO4)2F3/C composites exhibit high rate capability and cycling ability, showing 125.5, 106.4 mAh g-1 at 1.0 C, 3.0 C at room temperature, respectively, with high capacity retention up to 93.9% after 600th at 2 C.

  3. Atomic Layer Deposition of Al2O3-Ga2O3 Alloy Coatings for Li[Ni0.5Mn0.3Co0.2]O2 Cathode to Improve Rate Performance in Li-Ion Battery.

    Science.gov (United States)

    Laskar, Masihhur R; Jackson, David H K; Guan, Yingxin; Xu, Shenzhen; Fang, Shuyu; Dreibelbis, Mark; Mahanthappa, Mahesh K; Morgan, Dane; Hamers, Robert J; Kuech, Thomas F

    2016-04-27

    Metal oxide coatings can improve the electrochemical stability of cathodes and hence, their cycle-life in rechargeable batteries. However, such coatings often impose an additional electrical and ionic transport resistance to cathode surfaces leading to poor charge-discharge capacity at high C-rates. Here, a mixed oxide (Al2O3)1-x(Ga2O3)x alloy coating, prepared via atomic layer deposition (ALD), on Li[Ni0.5Mn0.3Co0.2]O2 (NMC) cathodes is developed that has increased electron conductivity and demonstrated an improved rate performance in comparison to uncoated NMC. A "co-pulsing" ALD technique was used which allows intimate and controlled ternary mixing of deposited film to obtain nanometer-thick mixed oxide coatings. Co-pulsing allows for independent control over film composition and thickness in contrast to separate sequential pulsing of the metal sources. (Al2O3)1-x(Ga2O3)x alloy coatings were demonstrated to improve the cycle life of the battery. Cycle tests show that increasing Al-content in alloy coatings increases capacity retention; whereas a mixture of compositions near (Al2O3)0.5(Ga2O3)0.5 was found to produce the optimal rate performance. PMID:27035035

  4. Structure and electrical resistance of (Al{sub 5,5}Cu{sub 1}){sub 200-X}Li{sub X} layers; Struktur und elektrischer Widerstand von (Al{sub 5,5}Cu{sub 1}){sub 100-X}Li{sub X}-Schichten

    Energy Technology Data Exchange (ETDEWEB)

    Lang, M.

    2005-11-29

    In the framework of the present thesis thew transition from amorphous AlCuLi layers ionto the quasi-crystalline phase should be studied. For this the atomic structure and the electrical resistance on in-situ produced amorphous (Al{sub 5,5}Cu{sub 1}){sub 100-X}Li{sub X} layers in the temperature range 2 KLi{sub X} the atoms position into the Friedel minima of the pairing potential. Up to about 26 at% this occurs mainly via a hybridization effect of the electrons from the valence band into the unoccupied Cu d-states. Above 26 at% Li this is reached increasingly by an increasement of the atomic-number density. In order to reach a decreasing of the atomic volume The Li losses its outer electron and decreases by this its radius. The maximum in the interference function I(K) at larger K values shifts parallely to the diameter of the Fermi sphere 2k{sub F} and is by this to be recognized as electronically induced. Electronic transport properties are shown, which could also be observed in other systems (NaSn,AlCuFe). In the range of more than 50 at% Li the density anomaly vanishes again and the atoms lie also without change of the volume near the Friedel minima. However the alloy losses thereby stability. The system behaves here similarly as comparable noble-metal polyvalent-element alloys.

  5. The conversion of a room temperature NaK loop to a high temperature MHD facility for Li/V blanket testing

    International Nuclear Information System (INIS)

    The Vanadium/Lithium system has been the recent focus of ANL's Blanket Technology Pro-ram, and for the last several years, ANL's Liquid Metal Blanket activities have been carried out in direct support of the ITER (International Thermonuclear Experimental Reactor) breeding blanket task area. A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the Near the development of insulator coatings. Design calculations, Hua and Gohar, show that an electrically insulating layer is necessary to maintain an acceptably low magneto-hydrodynamic (MHD) pressure drop in the current ITER design. Consequently, the decision was made to convert Argonne's Liquid Metal EXperiment (ALEX) from a 200 degrees C NaK facility to a 350 degrees C lithium facility. The upgraded facility was designed to produce MHD pressure drop data, test section voltage distributions, and heat transfer data for mid-scale test sections and blanket mockups at Hartmann numbers (M) and interaction parameters (N) in the range of 103 to 105 in lithium at 350 degrees C. Following completion of the upgrade work, a short performance test was conducted, followed by two longer multiple-hour, MHD tests, all at 230 degrees C. The modified ALEX facility performed up to expectations in the testing. MHD pressure drop and test section voltage distributions were collected at Hartmann numbers of 1000

  6. Conversion of a room temperature NaK loop to a high temperature MHD facility for Li/V blanket testing

    International Nuclear Information System (INIS)

    The Vanadium/Lithium system has been the recent focus of ANL's Blanket Technology Program, and for the last several years, ANL's Liquid Metal Blanket activities have been carried out in direct support of the ITER (International Thermonuclear Experimental Reactor) breeding blanket task area. A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the development of insulator coatings. Design calculations, Hua and Gohar, show that an electrically insulating layer is necessary to maintain an acceptably low magnetohydrodynamic (MHD) pressure drop in the current ITER design. Consequently, the decision was made to convert Argonne's Liquid Metal EXperiment (ALEX) from a 200 degree C NaK facility to a 350 degree C lithium facility. The upgraded facility was designed to produce MHD pressure drop data, test section voltage distributions, and heat transfer data for mid-scale test sections and blanket mockups at Hartmann numbers (M) and interaction parameters (N) in the range of 103 to 105 in lithium at 350 degree C. Following completion of the upgrade work, a short performance test was conducted, followed by two longer, multiple-hour, MHD tests, all at 230 degree C. The modified ALEX facility performed up to expectations in the testing. MHD pressure drop and test section voltage distributions were collected at Hartmann numbers of 1000. 4 refs., 2 figs

  7. Free energetics of carbon nanotube association in aqueous inorganic NaI salt solutions: Temperature effects using all-atom molecular dynamics simulations.

    Science.gov (United States)

    Ou, Shu-Ching; Cui, Di; Wezowicz, Matthew; Taufer, Michela; Patel, Sandeep

    2015-06-15

    In this study, we examine the temperature dependence of free energetics of nanotube association using graphical processing unit-enabled all-atom molecular dynamics simulations (FEN ZI) with two (10,10) single-walled carbon nanotubes in 3 m NaI aqueous salt solution. Results suggest that the free energy, enthalpy and entropy changes for the association process are all reduced at the high temperature, in agreement with previous investigations using other hydrophobes. Via the decomposition of free energy into individual components, we found that solvent contribution (including water, anion, and cation contributions) is correlated with the spatial distribution of the corresponding species and is influenced distinctly by the temperature. We studied the spatial distribution and the structure of the solvent in different regions: intertube, intratube and the bulk solvent. By calculating the fluctuation of coarse-grained tube-solvent surfaces, we found that tube-water interfacial fluctuation exhibits the strongest temperature dependence. By taking ions to be a solvent-like medium in the absence of water, tube-anion interfacial fluctuation shows similar but weaker dependence on temperature, while tube-cation interfacial fluctuation shows no dependence in general. These characteristics are discussed via the malleability of their corresponding solvation shells relative to the nanotube surface. Hydrogen bonding profiles and tetrahedrality of water arrangement are also computed to compare the structure of solvent in the solvent bulk and intertube region. The hydrophobic confinement induces a relatively lower concentration environment in the intertube region, therefore causing different intertube solvent structures which depend on the tube separation. This study is relevant in the continuing discourse on hydrophobic interactions (as they impact generally a broad class of phenomena in biology, biochemistry, and materials science and soft condensed matter research), and

  8. High-energy collision-induced dissociation of [M+Na]+ ions desorbed by fast atom bombardment of ceramides isolated from the starfish Distolasterias nipon.

    Science.gov (United States)

    Yoo, Ji Sun; Park, Taeseong; Bang, Geul; Lee, Chulhyun; Rho, Jung-Rae; Kim, Young Hwan

    2013-02-01

    Ten ceramides and four cerebrosides were extracted from the starfish Distolasterias nipon by solvent extraction, silica gel column chromatography and reversed-phase high-performance liquid chromatography. Structural identification was conducted using tandem mass spectrometry of monosodiated ions desorbed by fast atom bombardment. The complete structures of four cerebrosides were determined by a previously reported method. The high-energy collision-induced dissociation (CID) spectral characteristics of ceramides with various structures depend on the number and positions of double bonds on both the N-acyl and sphingoid chains, the presence of a hydroxyl group or a double bond at the C-4 position of the sphingoid chain and the presence of an α-hydroxy group on the N-acyl chain. The high-energy CID of the monosodiated ion, [M+Na](+), of each ceramide molecular species generated abundant ions, providing information on the composition of the fatty acyl chains and sphingoid long-chain bases. Each homologous ion series along the fatty acyl group and aliphatic chain of the sphingoid base was used for locating the double-bond positions of both chains and hydroxyl groups on the sphingoid base chain. The double-bond positions were also confirmed by the m/z values of abundant allylic even- and odd-electron ions, and the intensity ratio of the T ion peak relative to the O ion peak. This technique could determine the complete structures of ceramides and cerebrosides in an extract mixture and has great potential for determining other sphingolipids isolated from various biological sources. PMID:23378088

  9. NMR spin-lattice relaxation study of 7Li and 93Nb nuclei in Ti- or Fe-doped LiNbO3:Mg single crystals

    Directory of Open Access Journals (Sweden)

    Tae Ho Yeom

    2016-04-01

    Full Text Available In this study, to understand the effects of paramagnetic impurities, we investigated the temperature dependent of the spin-lattice relaxation times of pure LiNbO3, LiNbO3:Mg, LiNbO3:Mg/Ti, LiNbO3:Mg/Fe, and LiNbO3:Mg/Fe (thermally treated at 500°C single crystals. The results for the LiNbO3:Mg single crystals doped with Fe3+ or Ti3+ are discussed with respect to the site distribution and atomic mobility of Li and Nb. In addition, the effects of a thermal treatment on LiNbO3:Mg/Fe single crystals were examined based on the T1 analysis of 7Li and 93Nb. It was found that the presence of impurities in the crystals induced systematic changes of activation energies concerning atomic mobility.

  10. LiHo(PO34

    Directory of Open Access Journals (Sweden)

    Mokhtar Férid

    2009-02-01

    Full Text Available Lithium holmium(III polyphosphate(V, LiHo(PO34, belongs to the type I of polyphosphates with general formula ALn(PO34, where A is a monovalent cation and Ln is a trivalent rare earth cation. In the crystal structure, the polyphosphate chains spread along the b-axis direction, with a repeat period of four tetrahedra and 21 internal symmetry. The Li and Ho atoms are both located on twofold rotation axes and are surrounded by four and eight O atoms, leading to a distorted tetrahedral and dodecahedral coordination, respectively. The HoO8 polyhedra are isolated from each other, the closest Ho...Ho distance being 5.570 (1 Å.

  11. Mevlâna ve Kierkegaard’da Birey Tanrı İlişkisi The Relationship between the Individual and God in Mevlana and Kierkegaard

    Directory of Open Access Journals (Sweden)

    Vefa TAŞDELEN

    2013-07-01

    ını oluşturur. Onlar başlıca bu ilişkiyi tesis etme, insanın hayatına bireysel ve toplumsal düzeyde bir anlam katma ve düzen getirme amacını güderler. Yalnız peygamberler değil filozoflar da bu ilişki üzerinde durmuş, onun nasıl mümkün olabileceği hususunda görüşler öne sürmüş, bu şekilde “iman” konusuna felsefi bir derinlik kazandırmaya çalışmışlardır. Bu tutum felsefe tarihi boyunca genellikle Tanrı varlığının kanıtlanması, ruhun ölümsüzlüğünün temellendirilmesi şeklinde kendini göstermiştir. Mevlâna ve Kierkegaard, Tanrı’nın kanıtlanamayacağı konusunda hemfikirdirler. Onlara göre Tanrı için kanıt aramak iman açısında yetkinlik değil kusur, tamlık değil eksikliktir. İman, temelini Tanrı’nın kanıtlanabilir oluşunda değil kanıtlanamaz oluşunda, bilinebilir oluşunda değil bilinemez oluşunda bulur. Akıl bu konuyu anlamakta, dil bu konuyu anlatmakta yetersizdir. Mevlana ve Kierkegaard, birey ve Tanrı arasındaki ilişkiyi rasyonel bir zeminde değil, Tanrı’nın insana, insanın Tanrı’ya yönelimi doğrultusunda daha çok bir gönül ilişkisi olarak kurmak isterler. Kierkegaard için iman iki varoluş arasındaki sevgide ifadesini bulur. Mevlana’da ise kendi varlığını sevgilinin varlığında yeniden keşfetmede ortaya çıkar. Onlar Tanrı’dan insana gelen, insandan Tanrı’ya dönen, Tanrı’dan yine insana gelen, insandan insana, aşama aşama tüm varlığa, tüm evrene doğru yansıyan bir sevgi sarmalından söz ederler. Sonuçta inanma hali, varlığa karşı derin ve içtenlikli bir sevgi duymaya, yaratılanı yaratandan ötürü sevmeye, hoş ve güzel görmeye dönüşür. Bu yönelim temelini, imanın bir “aşk hali” olarak algılanmasında bulur. Çalışmamızda, Mevlana’nın ve Kierkegaard’un inanma tutumu, bu “aşk hali” bağlamında değerlendirilmeye çalışılacaktır.

  12. Investigation of hydrogen absorption in Li7VN4 and Li7MnN4.

    Science.gov (United States)

    He, Guang; Herbst, J F; Ramesh, T N; Pinkerton, F E; Meyer, M S; Nazar, Linda

    2011-05-21

    The hydrogen storage properties of Li(7)VN(4) and Li(7)MnN(4) were investigated both by experiment and by density functional theory calculations. Li(7)VN(4) did not sorb hydrogen under our experimental conditions. Li(7)MnN(4) was observed to sorb 7 hydrogen atoms through the formation of LiH, Mn(4)N, and ammonia gas. An applied pressurized mixture of H(2)/Ar and H(2)/N(2) gases was helpful to mitigate the release of NH(3) but could not prevent its formation. The introduction of N(2) also caused weight gain of the sample by re-nitriding the absorbed products LiH and Mn(4)N, which correlated with the presence of Li(2)NH, LiNH(2), and Mn(2)N detected by X-ray diffraction. While our observed results for Li(7)VN(4) and Li(7)MnN(4) differ in detail, they are in overall qualitative agreement with our theoretical work, which strongly suggests that both compounds are unlikely to form quaternary hydrides. PMID:21455525

  13. Effects of A-site non-stoichiometry on the structural and electrical properties of 0.96K0.5Na0.5NbO3-0.04LiSbO3 lead-free piezoelectric ceramics

    Institute of Scientific and Technical Information of China (English)

    Zhao Jing-Bo; Du Hong-Liang; Qu Shao-Bo; Zhang Hong-Mei; Xu Zhuo

    2011-01-01

    Effects of A-site non-stoichiometry on the structural and electrical properties of 0.96K0.5+xNa0.5+xNbO30.04LiSbO3 lead-free piezoelectric ceramics were examined for 0 < x < 0.02. The piezoelectric coefficients exhibited a maximum, d33 = 187 pC/N at x = 0.0075, coinciding with the maximum of the grain size and the apparent density at x = 0.0075. The apparent density and the piezoelectric coefficients decreased with increasing x at higher x which was likely due to the crystal geometrical distortion of 0.96K0.5+xNa0.5+xNbO3-0.04LiSbO3. In addition, super-large grains were found and this may be due to liquid phase sintering. Excess (K++Na+) attracted a sum of space charges to keep the charge neutral, resulting in charge leakage during the course of ceramic polarization, influencing the piezoelectric and ferroelectric properties. These findings are of importance for guiding the design of K0.5Na0.5NbO3-based lead-free ceramics with enhanced electrical properties.

  14. Electron and positron scattering from atoms

    International Nuclear Information System (INIS)

    Four distinct projects carried out are discussed. First, differential and integrated cross sections for the elastic scattering of low- and intermediate-energy (3-300 eV) positrons and electrons by argon atoms are calculated. Higher transport cross sections, representing moments of 1 - (cos theta)/sup n/, for these systems are also obtained for n = 1-4. Model potentials are used to represent the interactions between positrons or electrons and argon atoms. For each impact energy, the phase shifts of the lower partial waves are obtained exactly by numerical integration of the radial equation. Second, closed form expressions for the contributions of higher partial waves (2 ell > n-3) to the elastic scattering amplitude for various long range interactions, which fall off as r/sup -n/ as r → ∞, are obtained for n ranging from 3 to 8. Third, the differential and total cross sections for the formation of positronium in its ground state from Li and Na atoms by the impact of intermediate-energy positrons are calculated in the first Born and the distorted wave Born approximations. Finally, formation of positronium (Ps) in different states by the impact of intermediate energy (20-500 eV) positrons on atomic hydrogen are calculated using the first Born approximation (FBA) and the distorted-wave Born approximation

  15. Li2Se as a Neutron Scintillator

    International Nuclear Information System (INIS)

    We show that Li2Se:Te is a potential neutron scintillator material based on density functional calculations. Li2Se exhibits a number of properties favorable for efficient neutron detection, such as a high Li concentration for neutron absorption, a small effective atomic mass and a low density for reduced sensitivity to background gamma rays, and a small band gap for a high light yield. Our calculations show that Te doping should lead to the formation of deep acceptor complex VLi-TeSe, which can facilitate efficient light emission, similar to the emission activation in Te doped ZnSe

  16. Isotopic effects on stereodynamics for the two reactions: H + LiH+(v = 0, j = 0) --> H2 + Li+ and H+ + LiH(v = 0, j = 0) --> H2(+) + Li.

    Science.gov (United States)

    Li, Xiaohu; Wang, Meishan; Pino, Ilaria; Yang, Chuanlu; Wu, Jicheng

    2010-07-28

    The isotopic effects on stereodynamic properties for the title reactions occurring on the two lowest-lying electronic potential energy surfaces (PESs) of LiH(2)(+) are investigated in detail by means of the quasi-classical trajectory (QCT) method at a collision energy of 0.5 eV, using the ab initio potential energy surfaces (PESs) of Martinazzo et al. (J. Chem. Phys., 2003, 119, 11241). The corresponding reactions comprise: (i) H/D/T + LiH(+) --> HH/HD/HT + Li(+) and H + LiH(+)/LiD(+)/LiT(+) --> HH/HD/HT + Li(+); (ii) H(+)/D(+)/T(+) + LiH --> HH(+)/HD(+)/HT(+) + Li and H(+) + LiH/LiD/LiT --> HH(+)/HD(+)/HT(+) + Li. Differential cross sections (DCSs) and alignments of the product rotational angular momentum for all of these reactions are reported. The results illustrate that the reason for the abnormal behavior of the DCSs for the title reactions reported in the previous work is ascribed to the sensitive role of the projectile atomic mass, and indicate that the long-range interactions play a more important role than the mass factor in ion-molecule reactions. The current topic for this special mass combination system shows some new features of the stereodynamics differing from the previous studies for "typical" mass-combination reactions. PMID:20498910

  17. Electrochemical properties of LiPON films made from a mixed powder target of Li{sub 3}PO{sub 4} and Li{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Naoki; Inaba, Tadashi, E-mail: e0913@mosk.tytlabs.co.jp; Shiga, Tohru

    2012-01-01

    Lithium phosphorus oxynitride (LiPON) films were prepared by radio frequency magnetron sputtering. In order to control the atomic composition of the films, a mixture of Li{sub 3}PO{sub 4} and Li{sub 2}O powders was used as the sputtering target. The ionic conductivity of the films showed a maximum (6.4 Multiplication-Sign 10{sup -6} S/cm) when the molar ratio of Li{sub 3}PO{sub 4} to Li{sub 2}O in the target was 1:2. The films formed from a target not containing Li{sub 2}O showed good durability in air at the expense of slightly poorer ionic conductivity. This is probably due to the amount of Li in the film being significantly less which effectively suppressed absorption of CO{sub 2} in air.

  18. Electrochemical properties of LiPON films made from a mixed powder target of Li3PO4 and Li2O

    International Nuclear Information System (INIS)

    Lithium phosphorus oxynitride (LiPON) films were prepared by radio frequency magnetron sputtering. In order to control the atomic composition of the films, a mixture of Li3PO4 and Li2O powders was used as the sputtering target. The ionic conductivity of the films showed a maximum (6.4 × 10−6 S/cm) when the molar ratio of Li3PO4 to Li2O in the target was 1:2. The films formed from a target not containing Li2O showed good durability in air at the expense of slightly poorer ionic conductivity. This is probably due to the amount of Li in the film being significantly less which effectively suppressed absorption of CO2 in air.

  19. Effects of SrTiO3 on dielectric and piezoelectric properties of K0.48Na0.48Li0.04Nb0.96Ta0.04O3-based piezoceramics

    International Nuclear Information System (INIS)

    Highlights: ► Sodium potassium niobate based piezoceramics modified with SrTiO3 (ST) were prepared. ► Crystal structure, microstructure and dielectric properties of ceramics were investigated. ► Addition of ST more than 3 mol% changed ferroelectric behavior from normal to relaxor. ► Coexistence of two structures in ceramic with 1 mol% ST enhanced piezoelectric constant. - Abstract: In this study, (100 − x) K0.48Na0.48Li0.04Nb0.96Ta0.04O3 − xSrTiO3 (0 ≤ x ≤ 10) ceramics were fabricated via normal sintering of synthesized powder by using solid state reaction. All ceramics revealed pure perovskite structure, indicating formation of solid solution between KNNLT and ST up to 10%. With increasing x, the crystal structure of ceramics changed from orthorhombic to tetragonal and finally pseudocubic symmetry when x = 10. Ceramic containing 1% ST had orthorhombic and tetragonal symmetries, simultaneously. Investigation of the variation of dielectric constant of ceramics versus temperature revealed that for ceramic with x = 1, polymorphic phase transition (PPT) temperature between orthorhombic and tetragonal is less than room temperature. Thus coexistence of two different structures in this ceramic is due to vicinity of its composition to morphotropic phase boundary (MPB). As a result, the maximum piezoelectric constant was measured for this ceramic. Ceramics containing 5 and 7.5% ST tend to appear relaxor ferroelectric behavior which is because of chemical inhomogeneities in both A- and B-sites of the ABO3 perovskite structure.

  20. Structure characteristics and electrochemical properties of LiMn2O4 modified by LiCoO2

    Institute of Scientific and Technical Information of China (English)

    Zhenping Cai; Mingxun Li; Shigang Lu; Weihua Jin

    2005-01-01

    In order to improve the cycle performance of LiMn2O4, the modified LiMn2O4 was prepared by solid-state reactions using LiMn2O4 and LiCoO2 as precursors. XRD and EDS were used to study the structure properties of the modified LiMn2O4. The electrochemical properties of the modified LiMn2O4 were also investigated. The results show that Li and Co atoms could insert into the LiMn2O4 crystal lattice and a newly formed spinel phase, modified LiMn2O4 was obtained. The modified LiMn2O4 exhibits excellent cycle ability at room and elevated temperatures compared to pure LiMn2O4. The improved electrochemical stability of the modified LiMn2O4 attributes to the entrance of Li and Co ions inserted into the spinel crystal structure.

  1. The Mass Attenuation Coefficients, Electronic, Atomic, and Molecular Cross Sections, Effective Atomic Numbers, and Electron Densities for Compounds of Some Biomedically Important Elements at 59.5 keV

    OpenAIRE

    Burcu Akça; Erzeneoğlu, Salih Z.

    2014-01-01

    The mass attenuation coefficients for compounds of biomedically important some elements (Na, Mg, Al, Ca, and Fe) have been measured by using an extremely narrow collimated-beam transmission method in the energy 59.5 keV. Total electronic, atomic, and molecular cross sections, effective atomic numbers, and electron densities have been obtained by using these results. Gamma-rays of 241Am passed through compounds have been detected by a high-resolution Si(Li) detector and by using energy dispers...

  2. Role of Li in the low temperature synthesis of monoclinic celsian from (Ba, Li)-exchanged zeolite-A precursor

    Science.gov (United States)

    Ferone, Claudio; Esposito, Serena; Dell'Agli, Gianfranco; Pansini, Michele

    2005-11-01

    A sample of exhaustively Ba-exchanged zeolite-A was subjected to Li-exchange to obtain four samples of zeolite Ba-A bearing different Li amounts. These samples were subjected to thermal treatments at temperatures ranging from 200 to 1100 °C for times up to 28 hours. Samples of fully monoclinic celsian bearing an amount of impurities of 0.62 weight % Na 2O and 0.17 weight % Li 2O, 0.60 Na 2O weight % and 0.29 Li 2O weight %, and 0.67 Na 2O weight % and 0.55 Li 2O weight % were obtained after thermal treatments lasting 10 hours at 1100 °C, 4 hours at 1100 °C, and 4 hours at 1000 °C, respectively.

  3. Development of LiF:Mg,Cu,Si TL material (new KLT-300) with a low-residual signal and high-thermal stability.

    Science.gov (United States)

    Lee, J I; Kim, J L; Rahman, M S; Chang, S Y; Chung, K S; Choe, H S

    2007-01-01

    LiF-based thermoluminescence (TL) materials have been widely used for radiation dosimetry due to their attractive features. LiF:Mg,Cu,P is one of the most sensitive tissue-equivalent TL materials, approximately 40 times more sensitive than LiF:Mg,Ti (TLD-100), but it has two main drawbacks: a thermal loss of the TL sensitivity when annealed at temperatures>240 degrees C, and a relatively high-residual signal. Recently, LiF:Mg,Cu,Na,Si TL material was developed to overcome these drawbacks at the Korea Atomic Energy Research Institute, but it provided only marginal improvements in reducing the residual signal. The newly developed LiF:Mg,Cu,Si TL material has a significantly lower residual signal and a better stability to thermal treatments. In this article, the preparation method and some dosimetric properties (sensitivity and residual signal) of the new LiF:Mg,Cu,Si TL material are presented. At the end of the preparation procedures, a dual-step annealing method is introduced and this has proved as a very efficient method to reduce the high-temperature peak and is the cause of residual signal. Therefore, the high-temperature peak in the glow curve was significantly reduced. The sensitivity is approximately 20 times higher than that of TLD-100 and the residual signal was estimated to be approximately 0.04%. PMID:16968712

  4. Development of LiF:Mg,Cu,Si TL material (new KLT-300) with a low-residual signal and high-thermal stability

    International Nuclear Information System (INIS)

    LiF-based thermoluminescence (TL) materials have been widely used for radiation dosimetry due to their attractive features. LiF:Mg,Cu,P is one of the most sensitive tissue-equivalent TL materials, ∼40 times more sensitive than LiF:Mg,Ti (TLD-100), but it has two main drawbacks: a thermal loss of the TL sensitivity when annealed at temperatures >240 deg. C, and a relatively high-residual signal. Recently, LiF:Mg,Cu,Na,Si TL material was developed to overcome these drawbacks at the Korea Atomic Energy Research Inst., but it provided only marginal improvements in reducing the residual signal. The newly developed LiF:Mg,Cu,Si TL material has a significantly lower residual signal and a better stability to thermal treatments. In this article, the preparation method and some dosimetric properties (sensitivity and residual signal) of the new LiF:Mg,Cu,Si TL material are presented. At the end of the preparation procedures, a dual-step annealing method is introduced and this has proved as a very efficient method to reduce the high-temperature peak and is the cause of residual signal. Therefore, the high-temperature peak in the glow curve was significantly reduced. The sensitivity is ∼20 times higher than that of TLD-100 and the residual signal was estimated to be ∼0.04%. (authors)

  5. H2 adsorption in Li-decorated porous graphene

    International Nuclear Information System (INIS)

    Porous graphene (PG) has been decorated with Li atoms and subsequently studied the hydrogen (H2) adsorption characteristics, by using Density Functional Theory (DFT)-based calculations. A 2×2 PG has been decorated with eight Li atoms. Upto four H2 molecules get adsorbed on each Li atom. The maximum H2 storage capacity that could be achieved in 2×2PG-8Li is 8.95 wt% which is higher than the U.S. DOE’s revised target for the on-board vehicles. The average H2 adsorption binding energy is 0.535 eV/H2, which lies between 0.2-0.6 eV/H2 that is required for achieving adsorption and desorption at near ambient conditions. Thus, Li-decorated PG could be a viable option for on-board automobile applications

  6. Modified Li chains as atomic switches

    KAUST Repository

    Wunderlich, Thomas

    2013-09-06

    We present electronic structure and transport calculations for hydrogen and lithium chains, using density functional theory and scattering theory on the Green\\'s function level, to systematically study impurity effects on the transmission coefficient. To this end we address various impurity configurations. Tight-binding results allow us to interpret our the findings. We analyze under which circumstances impurities lead to level splitting and/or can be used to switch between metallic and insulating states. We also address the effects of strongly electronegative impurities.

  7. CuLi2Sn and Cu2LiSn: Characterization by single crystal XRD and structural discussion towards new anode materials for Li-ion batteries

    International Nuclear Information System (INIS)

    The stannides CuLi2Sn (CSD-427095) and Cu2LiSn (CSD-427096) were synthesized by induction melting of the pure elements and annealing at 400 °C. The phases were reinvestigated by X-ray powder and single-crystal X-ray diffractometry. Within both crystal structures the ordered CuSn and Cu2Sn lattices form channels which host Cu and Li atoms at partly mixed occupied positions exhibiting extensive vacancies. For CuLi2Sn, the space group F-43m. was verified (structure type CuHg2Ti; a=6.295(2) Å; wR2(F²)=0.0355 for 78 unique reflections). The 4(c) and 4(d) positions are occupied by Cu atoms and Cu+Li atoms, respectively. For Cu2LiSn, the space group P63/mmc was confirmed (structure type InPt2Gd; a=4.3022(15) Å, c=7.618(3) Å; wR2(F²)=0.060 for 199 unique reflections). The Cu and Li atoms exhibit extensive disorder; they are distributed over the partly occupied positions 2(a), 2(b) and 4(e). Both phases seem to be interesting in terms of application of Cu–Sn alloys as anode materials for Li-ion batteries. - Highlights: • First single crystal investigation of CuLi2Sn and Cu2LiSn clarifies contradictions from literature. • Lithium atoms are ordered in channels, which is interesting for application as anode materials for lithium ion batteries. • Structural relationships to binary Cu–Sn-phases are shown. • Close structural relationship between both ternary phases exists

  8. New rock salt-related oxides Li{sub 3}M{sub 2}RuO{sub 6} (M=Co, Ni): Synthesis, structure, magnetism and electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Laha, S. [Departamento de Químicas Inorganica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012 (India); Morán, E., E-mail: emoran@quim.ucm.es [Departamento de Químicas Inorganica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Sáez-Puche, R.; Alario-Franco, M.Á.; Dos santos-Garcia, A.J. [Departamento de Químicas Inorganica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Gonzalo, E.; Kuhn, A.; García-Alvarado, F. [Universidad CEU San Pablo, Facultad de Farmacia, Departamento de Química, 28668 Boadilla del Monte, Madrid (Spain); Sivakumar, T.; Tamilarasan, S.; Natarajan, S.; Gopalakrishnan, J. [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012 (India)

    2013-07-15

    We describe the synthesis, crystal structure, magnetic and electrochemical characterization of new rock salt-related oxides of formula, Li{sub 3}M{sub 2}RuO{sub 6} (M=Co, Ni). The M=Co oxide adopts the LiCoO{sub 2} (R-3m) structure, where sheets of LiO{sub 6} and (Co{sub 2}/Ru)O{sub 6} octahedra are alternately stacked along the c-direction. The M=Ni oxide also adopts a similar layered structure related to Li{sub 2}TiO{sub 3}, where partial mixing of Li and Ni/Ru atoms lowers the symmetry to monoclinic (C2/c). Magnetic susceptibility measurements reveal that in Li{sub 3}Co{sub 2}RuO{sub 6}, the oxidation states of transition metal ions are Co{sup 3+} (S=0), Co{sup 2+} (S=1/2) and Ru{sup 4+} (S=1), all of them in low-spin configuration and at 10 K, the material orders antiferromagnetically. Analogous Li{sub 3}Ni{sub 2}RuO{sub 6} presents a ferrimagnetic behavior with a Curie temperature of 100 K. The differences in the magnetic behavior have been explained in terms of differences in the crystal structure. Electrochemical studies correlate well with both magnetic properties and crystal structure. Li-transition metal intermixing may be at the origin of the more impeded oxidation of Li{sub 3}Ni{sub 2}RuO{sub 6} when compared to Li{sub 3}Co{sub 2}RuO{sub 6}. Interestingly high first charge capacities (between ca. 160 and 180 mAh g{sup −1}) corresponding to ca. 2/3 of theoretical capacity are reached albeit, in both cases, capacity retention and cyclability are not satisfactory enough to consider these materials as alternatives to LiCoO{sub 2}. - Graphical abstract: Two new rock salt related oxides of formula, Li{sub 3}M{sub 2}RuO{sub 6}, (M=Co, Ni) have been prepared. The M=Co oxide adopts the LiCoO{sub 2} (R-3m) structure and the M=Ni oxide adopts a similar layered structure related to Li{sub 2}TiO{sub 3,} monoclinic (C2/c), with partial mixing of Li and Ni/Ru atoms. For Li{sub 3}Co{sub 2}RuO{sub 6}, oxidation state for Ru is 4+ and antiferromagnetic (AFM) order is

  9. New rock salt-related oxides Li3M2RuO6 (M=Co, Ni): Synthesis, structure, magnetism and electrochemistry

    International Nuclear Information System (INIS)

    We describe the synthesis, crystal structure, magnetic and electrochemical characterization of new rock salt-related oxides of formula, Li3M2RuO6 (M=Co, Ni). The M=Co oxide adopts the LiCoO2 (R-3m) structure, where sheets of LiO6 and (Co2/Ru)O6 octahedra are alternately stacked along the c-direction. The M=Ni oxide also adopts a similar layered structure related to Li2TiO3, where partial mixing of Li and Ni/Ru atoms lowers the symmetry to monoclinic (C2/c). Magnetic susceptibility measurements reveal that in Li3Co2RuO6, the oxidation states of transition metal ions are Co3+ (S=0), Co2+ (S=1/2) and Ru4+ (S=1), all of them in low-spin configuration and at 10 K, the material orders antiferromagnetically. Analogous Li3Ni2RuO6 presents a ferrimagnetic behavior with a Curie temperature of 100 K. The differences in the magnetic behavior have been explained in terms of differences in the crystal structure. Electrochemical studies correlate well with both magnetic properties and crystal structure. Li-transition metal intermixing may be at the origin of the more impeded oxidation of Li3Ni2RuO6 when compared to Li3Co2RuO6. Interestingly high first charge capacities (between ca. 160 and 180 mAh g−1) corresponding to ca. 2/3 of theoretical capacity are reached albeit, in both cases, capacity retention and cyclability are not satisfactory enough to consider these materials as alternatives to LiCoO2. - Graphical abstract: Two new rock salt related oxides of formula, Li3M2RuO6, (M=Co, Ni) have been prepared. The M=Co oxide adopts the LiCoO2 (R-3m) structure and the M=Ni oxide adopts a similar layered structure related to Li2TiO3, monoclinic (C2/c), with partial mixing of Li and Ni/Ru atoms. For Li3Co2RuO6, oxidation state for Ru is 4+ and antiferromagnetic (AFM) order is found below 10 K while for the analogous Li3Ni2RuO6 , Ru oxidation state is 5+ and a ferrimagnetic (FM) behavior with a Curie temperature of 100 K is found. Electrochemical studies correlate well with both

  10. Dispersion coefficients for H and He interactions with alkali-metal and alkaline-earth-metal atoms

    International Nuclear Information System (INIS)

    The van der Waals coefficients C6, C8, and C10 for H and He interactions with the alkali-metal (Li, Na, K, and Rb) and alkaline-earth-metal (Be, Mg, Ca, and Sr) atoms are determined from oscillator strength sum rules. The oscillator strengths were computed using a combination of ab initio and semiempirical methods. The dispersion parameters generally agree with close to exact variational calculations for Li-H and Li-He at the 0.1% level of accuracy. For larger systems, there is agreement with relativistic many-body perturbation theory estimates of C6 at the 1% level. These validations for selected systems attest to the reliability of the present dispersion parameters. About half the present parameters lie within the recommended bounds of the Standard and Certain compilation [J. Chem. Phys. 83, 3002 (1985)

  11. Nuclear magnetic resonance studies of atomic motion in borohydride-based materials: Fast anion reorientations and cation diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Skripov, A.V., E-mail: skripov@imp.uran.ru; Soloninin, A.V.; Babanova, O.A.; Skoryunov, R.V.

    2015-10-05

    Highlights: • Solid solutions LiBH{sub 4}–LiI: extremely fast BH{sub 4} reorientations down to low T. • LiLa(BH{sub 4}){sub 3}Cl: Li-ion diffusive jumps and BH{sub 4} reorientations at the same frequency scale. • Dramatic acceleration of B{sub 12}H{sub 12} reorientations in the disordered phase of Na{sub 2}B{sub 12}H{sub 12}. • Fast Na-ion diffusion in the disordered phase of Na{sub 2}B{sub 12}H{sub 12}. - Abstract: Two basic types of thermally activated atomic jump motion are known to exist in solid borohydrides and the related systems: the reorientations of complex anions ([BH{sub 4}]{sup −}, [B{sub 12}H{sub 12}]{sup 2−}) and the translational diffusion of metal cations or complex anions. This paper reviews recent progress in nuclear magnetic resonance (NMR) studies of these jump processes in complex hydrides, such as solid solutions of halide anions in borohydrides, bimetallic borohydrides and borohydride–chlorides, borohydride–amides, and B{sub 12}H{sub 12}-based compounds. The emphasis is put on the systems showing fast-ion conductivity. For these systems, we discuss a possible relation between the reorientational motion of complex anions and the translational motion of metal cations.

  12. Li2Se:Te as a neutron scintillator

    International Nuclear Information System (INIS)

    We show that Li2Se:Te is a potential neutron scintillator material based on density functional calculations. Li2Se exhibits a number of properties favorable for efficient neutron detection, such as a high Li concentration for neutron absorption, a small effective atomic mass and a low density for reduced sensitivity to background gamma rays, and a small band gap for a high light yield. Our calculations show that Te doping should lead to the formation of deep acceptor complex VLi–TeSe, which can facilitate efficient light emission, similar to the emission activation in Te doped ZnSe. - Highlights: • Te doped Li2Se is proposed as a promising neutron scintillator based on density functional calculations. • Li2Se has a high Li concentration, a low density, and a small band gap, favorable for neutron detection. • Li2Se can be activated by VLi–TeSe

  13. Effects of the addition of Li0.8Ni0.2Nb0.96O3 on the structure and electrical properties of K0.48Na0.52NbO3 lead-free piezoceramics

    International Nuclear Information System (INIS)

    Highlights: • A new solid solution system of K0.48Na0.52NbO3–Li0.8Ni0.2Nb0.96O3 was investigated. • Li0.8Ni0.2Nb0.96O3 was found to act as a sintering aid. • The Ni2+ ions were confirmed to enter the B-sites and lead to the formation of the secondary phase. • Qm was improved significantly by increasing Li0.8Ni0.2Nb0.96O3 content. - Abstract: Lead-free K0.48Na0.52NbO3 (KNN) ceramics doped with Li0.8Ni0.2Nb0.96O3 (LNN) were prepared by the mixed oxide method. The structure, microstructure, and electrical properties of the ceramics were investigated systematically. All the samples exhibited the main orthorhombic perovskite phase structure, and the secondary phase K5.75Nb10.85O30 was detected when x ≥ 0.010. Our work revealed that the Ni2+ ions entered into the B-site and lead to the formation of small amounts of the secondary phase. Moreover, the addition of LNN increased the density of the KNN ceramics. With increasing addition of LNN, the TC increased while the TO-T decreased, respectively. The ceramic doped with 2 mol% LNN exhibited optimum electrical properties with Pr of 23.92 μC/cm2, d33 of 110 ± 3 pC/N, kp of 27.15% and kt of 27.75%. The Qm increased significantly with increasing LNN content, and the maximum value of 195 is obtained at x = 0.035

  14. Excitation and charge transfer in low-energy hydrogen atom collisions with neutral atoms: Theory, comparisons, and application to Ca

    CERN Document Server

    Barklem, Paul S

    2016-01-01

    A theoretical method for the estimation of cross sections and rates for excitation and charge transfer processes in low-energy hydrogen atom collisions with neutral atoms, based on an asymptotic two-electron model of ionic-covalent interactions in the neutral atom-hydrogen atom system, is presented. The calculation of potentials and non-adiabatic radial couplings using the method is demonstrated. The potentials are used together with the multi-channel Landau-Zener model to calculate cross sections and rate coefficients. The main feature of the method is that it employs asymptotically exact atomic wavefunctions, which can be determined from known atomic parameters. The method is applied to Li+H, Na+H, and Mg+H collisions, and the results compare well with existing detailed full-quantum calculations. The method is applied to the astrophysically important problem of Ca+H collisions, and rate coefficients are calculated for temperatures in the range 1000-20000 K.

  15. Grazing incidence collisions of ions and atoms with surfaces: from charge exchange to atomic diffraction

    International Nuclear Information System (INIS)

    This thesis reports two studies about the interaction with insulating surfaces of keV ions or atoms under grazing incidence. The first part presents a study of charge exchange processes occurring during the interaction of singly charged ions with the surface of NaCl. In particular, by measuring the scattered charge fraction and the energy loss in coincidence with electron emission, the neutralization mechanism is determined for S+, C+, Xe+, H+, O+, Kr+, N+, Ar+, F+, Ne+ and He+. These results show the importance of the double electron capture as neutralization process for ions having too much potential energy for resonant capture and not enough for Auger neutralization. We have also studied the ionisation of the projectile and of the surface, and the different Auger-like neutralization processes resulting in electron emission, population of conduction band or excited state. For oxygen scattering, we have measured an higher electron yield in coincidence with scattered negative ion than with scattered atom suggesting the transient formation above the surface of the oxygen doubly negative ion. The second study deals with the fast atom diffraction, a new phenomenon observed for the first time during this work. Due to the large parallel velocity, the surface appears as a corrugated wall where rows interfere. Similarly to the Thermal Atom Scattering the diffraction pattern corresponds to the surface potential and is sensitive to vibrations. We have study the H-NaCl and He-LiF atom-surface potentials in the 20 meV - 1 eV range. This new method offers interesting perspectives for surface characterisation. (author)

  16. Structural evolution upon decomposition of the LiAlH4 + LiBH4 system

    International Nuclear Information System (INIS)

    Highlights: • The desorption mechanism of LiBH4 + LiAlH4 was studied by in situ SR-PXD • The formation of unidentified intermediate was proved by experimental evidences. • This intermediate is based on Li, B, Al, H atoms. - Abstract: In the present work we focus the attention on the phase structural transformations occurring upon the desorption process of the LiBH4 + LiAlH4 system. This study is conducted by means of manometric–calorimetric, in situ Synchrotron Radiation Powder X-ray Diffraction (SR-PXD) and exsitu Solid State Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) measurements. The desorption reaction is characterized by two main dehydrogenation steps starting at 320 and 380 °C, respectively. The first step corresponds to the decomposition of LiAlH4 into Al and H2via the formation of Li3AlH6 whereas the second one refers to the dehydrogenation of LiBH4 (molten state). In the range 328–380 °C, the molten LiBH4 reacts with metallic Al releasing hydrogen and forming an unidentified phase which appears to be an important intermediate for the desorption mechanism of LiBH4–Al-based systems. Interestingly, NMR studies indicate that the unknown intermediate is stable up to 400 °C and it is mainly composed of Li, B, Al and H. In addition, the NMR measurements of the annealed powders (400 °C) confirm that the desorption reaction of the LiBH4 + Al system proceeds via an amorphous boron compound

  17. An Analytical Model for Adsorption and Diffusion of Atoms/Ions on Graphene Surface

    Directory of Open Access Journals (Sweden)

    Yan-Zi Yu

    2015-01-01

    Full Text Available Theoretical investigations are made on adsorption and diffusion of atoms/ions on graphene surface based on an analytical continuous model. An atom/ion interacts with every carbon atom of graphene through a pairwise potential which can be approximated by the Lennard-Jones (L-J potential. Using the Fourier expansion of the interaction potential, the total interaction energy between the adsorption atom/ion and a monolayer graphene is derived. The energy-distance relationships in the normal and lateral directions for varied atoms/ions, including gold atom (Au, platinum atom (Pt, manganese ion (Mn2+, sodium ion (Na1+, and lithium-ion (Li1+, on monolayer graphene surface are analyzed. The equilibrium position and binding energy of the atoms/ions at three particular adsorption sites (hollow, bridge, and top are calculated, and the adsorption stability is discussed. The results show that H-site is the most stable adsorption site, which is in agreement with the results of other literatures. What is more, the periodic interaction energy and interaction forces of lithium-ion diffusing along specific paths on graphene surface are also obtained and analyzed. The minimum energy barrier for diffusion is calculated. The possible applications of present study include drug delivery system (DDS, atomic scale friction, rechargeable lithium-ion graphene battery, and energy storage in carbon materials.

  18. Resolving all atoms of an alkali halide via nanomodulation of the thin NaCl film surface using the Au(111) reconstruction

    OpenAIRE

    Lauwaet, Koen; Schouteden, Koen; Janssens, Ewald; Van Haesendonck, Chris; Lievens, Peter; Trioni, M. I.; Giordano, L.; Pacchioni, G.

    2012-01-01

    We investigated the local influence of the Au(111) herringbone reconstruction on the properties of thin adsorbed NaCl films using cryogenic scanning tunneling microscopy (STM) and spectroscopy. Depending on the local hcp versus fcc character of the reconstruction, NaCl adsorption gives rise to a different shift of the Au(111) surface state toward the Fermi level, in agreement with ab initio calculations. Such lateral modulation may allow for tunable nanostructuring of thin insulating films, w...

  19. Analyzing the reasons of LiNa defeated in 2012 WTA Stuttgart Grand Prix 1/4 final%2012年WTA斯图加特大奖赛1/4决赛李娜失利的原因分析

    Institute of Scientific and Technical Information of China (English)

    俞婧; 胡凯; 俞姝

    2012-01-01

    By using video observation and mathematical statistics, the paper makes a technical statistical analysis of LiNa and Radwanska in Stuttgart Grand Prix 1/4 final. The research demonstrates that: too much unforced faults, few winning points and a lower rate of break by himslef are the main reasons lead to LiNa losing in the game. It also shows that: the three indicators of success rate of serve , Ace ball, Double faults are not the real reasons for the failure of the LiNa. In addition , The winning points is an important factor in the game of Lina department also in- duced by the reason of failure and net score a little underdogs need to strengthen.%运用录像观察和数理统计等研究方法,对2012年wTA顶级巡回赛斯图加特保时捷大奖赛四分之一决赛中李娜与拉德万斯卡的技战术进行统计分析。研究显示:非受迫性失误过多,自身破发率低是李娜失利的主要原因。同时指出:一发球成功率、ACES球、双发失误三项指标并非孥娜失利的真正原因所在。制胜分是李娜维系比赛的重要因素也是诱发失误的原因,李娜网前得分稍处下风需加强。

  20. New intermetallic phases in the Cu-Li-Sn system. The lithium-rich phases Li{sub 3}CuSn and Li{sub 6}Cu{sub 2}Sn{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Fuertauer, Siegfried; Flandorfer, Hans [Wien Univ. (Austria). Inst. fuer Anorganische Chemie (Materialchemie); Effenberger, Herta S. [Wien Univ. (Austria). Inst. fuer Mineralogie und Kristallographie

    2016-04-01

    The Li-rich ternary intermetallic compounds with the idealized end-member compositions Li{sub 3}CuSn (CSD-427099) and Li{sub 6}Cu{sub 2}Sn{sub 3} (CSD-427100) were synthesized from the pure elements by induction melting in Ta crucibles and annealing at 400 {sup circle} C. Both powder and single-crystal XRD investigations were performed. Li{sub 3}CuSn crystallizes in space group P6/mmm [a=4.5769(2), c=8.461(2) Aa; wR{sub 2}=0.073 for 180 unique F{sup 2}-values and 25 free variables]. All atoms are located along [00z], [1/3 2/3 z] and [2/3 1/3 z]; individual sites are arranged in layers parallel to (00.1). One site is fully, one partially occupied by Sn atoms. Fully but mixed occupation with Cu and Li atoms was found for one site. The remaining electron-density distribution resulting from the strong anisotropic displacement parallel to the c axis is considered in four further sites, which are mixed occupied with (Li, Cu, □), but modelled solely by Li atoms. The crystal structure exhibits analogies with that of Li{sub 2}CuSn (F anti 43m); comparable layers occur parallel to {111} but the stacking sequence and packing density differs adopting cubic symmetry. In Li{sub 6}Cu{sub 2}Sn{sub 3} [space group R anti 32/m, a=4.5900(2), c=30.910(6) Aa; wR{sub 2}=0.039 for 253 unique F{sup 2}-values for 25 free variables] all atoms are arranged again at (00z), (1/3 2/3 z) and (2/3 1/3 z). Three sites are fully occupied (two by Sn atoms, a further one by Li atoms). Three additional positions are mixed occupied by Cu and Li atoms. The crystal structure is closely related to that of the binary phases Li{sub 13}Sn{sub 5} and Li{sub 5}Sn{sub 2}; the substitution of Li by Cu atoms and vice versa is evident. The structural relationship to Li{sub 13}Ag{sub 5}Si{sub 6}, which is permeable for Li ions, makes the title compound interesting as anode material in Li-ion batteries.